79 results on '"C. D. Knight"'
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2. Lysine (protein) requirements of lactating sows
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Casey Neill, J. Connor, C. D. Knight, Kevin J Touchette, Pariat Srichana, James L Usry, G. L. Allee, and Laura L Greiner
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lysine ,General Veterinary ,040301 veterinary sciences ,Lysine ,0402 animal and dairy science ,Randomized block design ,lactation ,04 agricultural and veterinary sciences ,Non Ruminant Nutrition ,Biology ,Body weight ,040201 dairy & animal science ,0403 veterinary science ,Animal science ,medicine.anatomical_structure ,Research council ,Lactation ,sow ,medicine ,AcademicSubjects/SCI00960 ,Animal Science and Zoology ,Parity (mathematics) - Abstract
Five experiments were conducted to evaluate the lysine (Lys) requirements of lactating sows. All diets were formulated to be isocaloric 3.46 Mcal ME/kg and met or exceeded National Research Council recommendations. In all studies, sow feed intake, body weight loss/gain, subsequent reproduction, and litter growth rate (LGR) were evaluated. The data were analyzed as randomized complete block design using generalized linear model in SAS with parity as a block. Two hundred and sixty-four primiparous sows (PIC Camborough 22) were randomly allotted to one of five lactation treatments (total Lys of 0.95%, 1.05%, 1.15%, 1.25%, and 1.35%) in Exp. 1 from August 2005 through October 2005. As daily total dietary Lys intake increased from 52.10 to 77.53 g, piglet ADG and daily litter gain linearly improved (P < 0.01). From February 2007 through April 2007, 336 multiparous sows (parity 4 and older, PIC Camborough 29) were randomly allotted to one of five lactation treatments (total Lys 0.85%, 0.95%, 1.05%, 1.15%, or 1.25%) in Exp. 2. As dietary total Lys increased from 0.85% to 1.25% of the diet, there were no significant differences in litter performance, such as ADG, daily litter gain, and the number of pigs weaned. Experiment 3 was conducted from October 2008 through January 2009. Two hundred and seventy-nine primiparous gilts (PIC Camborough 29) were randomly allotted to one of five lactation treatments (total Lys 1.14%, 1.25%, 1.35%, 1.46%, and 1.57%). Actual total Lys intakes increased from 56.74 to 77.12 g/d. Feeding total dietary Lys quadratically decreased (P < 0.01) weaning-to-estrus interval and increased percentage bred by 10 d (P = 0.02). In Exp. 4, 200 sows (parity 4 and older, PIC Camborough 29) were randomly allotted to one of five treatments (0.85%, 0.95%, 1.05%, 1.15%, or 1.25% total Lys) from January 2008 through March 2008. As dietary total Lys increased from 42.40 to 66.15 g/d, sow body weight and LGRs were not influenced by dietary total Lys intakes. In Exp. 5, 324 parity 3 sows (PIC Camborough 29) were randomly allotted to one of five treatments (0.77%, 0.92%, 1.08%, 1.23%, and 1.38% total Lys) from August 2009 through October 2009. As daily dietary total Lys intake increased from 39.44 to 67.32 g, the percentage of sows bred by 10 d increased (P = 0.02), as well as the LGR. A broken-line quadratic regression analysis demonstrated that the total Lys requirement for LGR for parity 1 females is calculated as 72.68 − [6.04 × (3.55 − LGR)] and for parity 3+ females as 92.03 − [11.9 × (4.24 − LGR)].
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- 2020
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3. The use of feed-grade amino acids in lactating sow diets
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Kevin J Touchette, Casey Neill, J. Connor, Pairat Srichana, Laura L Greiner, James L Usry, G. L. Allee, and C. D. Knight
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0301 basic medicine ,Litter (animal) ,Biology ,Biochemistry ,03 medical and health sciences ,chemistry.chemical_compound ,Animal science ,Valine ,Lactation ,medicine ,Weaning ,Animal nutrition ,lcsh:SF1-1100 ,chemistry.chemical_classification ,Meal ,Amino acid ratio ,Methionine ,lcsh:Veterinary medicine ,Research ,0402 animal and dairy science ,L-lysine ,04 agricultural and veterinary sciences ,040201 dairy & animal science ,Amino acid ,030104 developmental biology ,medicine.anatomical_structure ,chemistry ,Sow ,lcsh:SF600-1100 ,Animal Science and Zoology ,lcsh:Animal culture ,Food Science ,Biotechnology - Abstract
Background The use of feed grade amino acids can reduce the cost of lactation feed. With changing genetics, increasing feed costs, and higher number of pigs weaned with heavier wean weights further evaluation of higher inclusion levels of feed-grade amino acid in lactation diets than previously published is warranted. Two experiments (Exp.) were conducted to determine the optimal inclusion level of L-lysine HCl to be included in swine lactation diets while digestible lysine levels remain constant across dietary treatments and allowing feed grade amino acids to be added to the diet to maintain dietary ratios relative to lysine to maximize litter growth rate and sow reproductive performance. Furthermore, the studies were to evaluate minimal amino acid ratios relative to lysine that allows for optimal litter growth rate and sow reproductive performance. Results Exp. 1: Increasing L-lysine HCl resulted in similar gilt feed intake, litter, and reproductive performance. Average litter gain from birth to weaning was 2.51, 2.49, 2.59, 2.43, and 2.65 kg/d when gilts were fed 0.00, 0.075, 0.150, 0.225, and 0.30% L-lysine HCl, respectively. Exp. 2: The average litter gain from birth to weaning was 2.68, 2.73, 2.67, 2.70, and 2.64 kg/d (P
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- 2018
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4. The impact of feeding supplemental chelated trace minerals on shell quality, tibia breaking strength, and immune response in laying hens
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Megharaja K. Manangi, C. D. Knight, M. Vazques-Añon, S. Carter, and J. D. Richards
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Methionine ,chemistry.chemical_element ,Manganese ,Zinc ,Breaking strength ,chemistry.chemical_compound ,Immune system ,Animal science ,chemistry ,Biochemistry ,Animal Science and Zoology ,Chelation ,Tibia ,Eggshell - Abstract
SUMMARY The objective of this study was to investigate the impact of long-term inclusion of the trace elements zinc, copper, and manganese chelated with the hydroxy analogue of methionine on layer performance, eggshell quality, tibia breaking strength, and immune response. A total of 216 Hy-Line W-36 laying hens were allocated to 6 treatments with 36 pens/treatment and 1 hen/cageusingarandomizedcompleteblockdesign.Therewere6treatmentswithsupplemental Zn-Cu-Mn, as follows: T1 0-0-0 ppm, T2 20-5-20 ppm as sulfates, T3 20-5-20 ppm as chelates, T4 40-10-40 ppm as sulfates, T5 40-10-40 ppm as chelates, and T6 80-10-80 as sulfates. The feeding of dietary treatments started at wk 24 pullet age and measurements of the key parameters were made from wk 44 to 80. Overall results (one-way ANOVA) indicated a significant treatment effect (P 0.05) response to T1 and T6 but different (P < 0.05) from T2. Factorial analysis of the data showed an improvement in shell breaking strength (P < 0.05 at wk 68), shell thickness (P = 0.08 at wk 68; P = 0.03 at wk 74), tibia breaking strength (P = 0.07) and antibody (Ab) titers to SRBCs (P < 0.05 at wk 63; 1 wk after secondary antigen challenge) in hens fed chelated trace mineral when compared to inorganic trace minerals. In summary, feeding laying hens’ diets containing supplemental chelated trace minerals showed improvements in eggshell thickness and immune response when compared to inorganic salts at specific time points measured during the latter part of the laying cycle.
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- 2015
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5. Relationship of Delayed-Type Hypersensitivity and Acquired Cellular Resistance in Experimental Airborne Tuberculosis
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Shapiro, C. D. Knight, Harding, G. E., and Smith, D. W.
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- 1974
6. Effect of carbohydrase and protease on growth performance and gut health of young broilers fed diets containing rye, wheat, and feather meal
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Frances Yan, Julia J. Dibner, C. D. Knight, and Mercedes Vazquez-Anon
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0301 basic medicine ,Male ,Lutein ,Glycoside Hydrolases ,Clostridium perfringens ,medicine.medical_treatment ,Carbohydrase ,medicine.disease_cause ,Feed conversion ratio ,03 medical and health sciences ,chemistry.chemical_compound ,Ileum ,medicine ,Animals ,Food science ,Asymptomatic Infections ,Poultry Diseases ,Triticum ,Protease ,biology ,Feather meal ,Secale ,digestive, oral, and skin physiology ,0402 animal and dairy science ,food and beverages ,04 agricultural and veterinary sciences ,General Medicine ,Feathers ,040201 dairy & animal science ,Animal Feed ,Small intestine ,Enteritis ,Diet ,030104 developmental biology ,medicine.anatomical_structure ,chemistry ,Dietary Supplements ,biology.protein ,Clostridium Infections ,Animal Science and Zoology ,Animal Nutritional Physiological Phenomena ,Digestion ,Chickens ,Peptide Hydrolases - Abstract
An experiment was conducted to characterize a gut health challenge model consisting of a diet containing rye, wheat, and feather meal and a mild mixed-species Eimeria challenge, and to evaluate the effect of carbohydrase and protease on growth performance and gut health of young broilers. The study included 4 treatments: negative control, carbohydrase alone, protease alone, and combination of carbohydrase and protease. Each test diet was fed to 18 battery pens of broilers with 8 male birds per pen from 0 to 22 d of age. Carbohydrase improved body weight, feed intake, and feed conversion ratio (FCR) on d 7, 14, and 21(P < 0.01). Protease increased body weight on d 7 and 21 and improved 0 to 7 d FCR (P < 0.05). More lymphocyte infiltration was observed in small intestine mucosa of negative control birds on d 8, carbohydrase supplementation lessened this. Both carbohydrase and protease reduced digesta viscosity on d 22 with the carbohydrase effect being the greater of the two, and the combination effect was not different from the carbohydrase effect alone (P < 0.01). Ileal Clostridium perfringens of 15-day-old broilers was decreased by carbohydrase, a further reduction was achieved by combining carbohydrase with protease (P = 0.01). Liver vitamin E concentration on d 15 (P < 0.01) and 22 (P = 0.02) was increased by carbohydrase, and the carbohydrase effect was greater in the presence of protease on d 22 (P = 0.04). Plasma α-1-acid glycoprotein level and liver Zn and Cu concentrations of broilers were reduced by carbohydrase on d 15 (P < 0.01). Broilers fed carbohydrase had higher levels of plasma zeaxanthin on d 22 and higher levels of plasma lutein on d 15 and 22 (P < 0.01). In summary, a rye wheat based diet containing feather meal when fed to broilers in addition to a mild Eimeria challenge induced subclinical enteritis characterized by digestion inefficiency, dysbacteriosis, inflammation, and gut barrier failure; carbohydrase and protease could be effective tools to improve growth performance and gut health of broilers suffering from this type of subclinical enteritis.
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- 2016
7. Interference Drag Modeling and Experiments for a High-Reynolds-Number Transonic Wing
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Frank K. Lu, Christopher J. Roy, Joseph A. Schetz, Eric M. Braun, and Kyle C. D. Knight
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Engineering ,Drag coefficient ,business.industry ,K-epsilon turbulence model ,Aerospace Engineering ,Mechanics ,Flow separation ,Drag ,Parasitic drag ,Wave drag ,Drag divergence Mach number ,Aerospace engineering ,business ,Reynolds-averaged Navier–Stokes equations - Abstract
Multidisciplinary Design Optimization (MDO) studies show the Strut/Truss Braced Wing (SBW/TBW) concept has the potential to save a significant amount of fuel over conventional designs. For the SBW/TBW concept to achieve these reductions, the interference drag at the wing strut juncture must be small compared to other drag sources. Computational Fluid Dynamics (CFD) studies have indicated that the interference drag is small enough to be manageable. However, the RANS formulation and turbulence models used in these studies have not been validated for high Reynolds number transonic junction flows. This study assesses turbulence models by comparing flow separation characteristics obtained from experiment and CFD. The test model used is a NACA 0012 wing of aspect ratio 2 at Mach number of 0.76 and a Reynolds number of 6 million with varying angle of attack. The CFD study involved an 18.8 million cell structured grid of the wind tunnel test section using the ANSYS Fluent 12.0 solver. The k-ω SST turbulence model was the main turbulence model employed. Experiments were conducted in a high Reynolds number transonic Ludwieg tunnel. The wing was tested at different Mach numbers and inlet conditions to account for some of the experimental variations. Porous walls eliminate shock reflection across the tunnel. Surface oil flow visualization is used to indicate the interference flow patterns. The assessment shows CFD overpredicts separation and therefore interference drag, likely due to deficiencies in the turbulence model. Nomenclature
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- 2012
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8. Microbial Imprinting in Gut Development and Health
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J. D. Richards, Julia J. Dibner, and C. D. Knight
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Vertebrate ,Biology ,Gut flora ,biology.organism_classification ,Germline ,Immune system ,Evolutionary biology ,biology.animal ,Immunology ,Animal Science and Zoology ,Epigenetics ,Imprinting (psychology) ,Stem cell ,Adult stem cell - Abstract
SUMMARY The microbial community of the gastrointestinal system has an enormous impact on the vertebrate host. The relationship begins at birth or hatch and evolves to a stable ecosystem in which diverse, and unique, niches are created and inhabited by microorganisms. These microbial populations tend to be similar within a host species (and even across host species), but each system is a unique construct resulting from its individual history of mutual influence. The development of the system, both microbial and host, begins in the perinatal animal. The timing of this developmental process is suggestive of imprinting, the process of epigenetic evolution of somatic stem cells. (Imprinted changes are thought not to involve the germ line, i.e., are not inherited by the next generation of the host animal, but are genetic changes that can be passed on to the daughter cells of the imprinted proliferative stem cell.) This review briefly discusses the development of the gastrointestinal system, including both the microbiota and its perinatal host. The effects of the microflora on enteric and immune cells are described. Effects of attempts to restrict contact between the mucosal immune system and the microbiota are addressed, along with further data that would be required to demonstrate that the effects of the gut microbiota on mucosal immune development are restricted to an ontogenetic window. Finally, the consequences of a failure to achieve a relationship of mutual tolerance between the microbiota and the host and some mechanisms to facilitate this process are discussed.
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- 2008
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9. Effect of Methionine Source and Dietary Crude Protein Level on Growth Performance, Carcass Traits and Nutrient Retention in Chinese Color-feathered Chicks
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C. T. Zheng, G. L. Song, M. V찼zquez A챰처n, G. F. Yi, P. B. Xi, Y. C. Lin, Z. Y. Jiang, and C. D. Knight
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Methionine ,Thigh muscle ,Protein level ,Biology ,Feed conversion ratio ,Breast muscle ,Whole body composition ,chemistry.chemical_compound ,Nutrient ,Starter ,chemistry ,Animal Science and Zoology ,Food science ,Food Science - Abstract
A total of 1,200 LinNan Chinese color-feathered chicks were used to study the effects of methionine source [DL-2-hydroxy-4-methylthio-butanoic acid (HMTBa) or DL-methionine (DLM)] and dietary crude protein (CP) level on growth performance, carcass traits, and whole-body nitrogen and fat retention. The trial was designed as a 2x2 factorial arrangement, including two CP levels (adequate and low) and two methionine sources (HMTBa and DL-methionine). Diets were formulated for three phases, starter (0-21 d), grower (21-42 d), and finisher (42-63 d). Chicks fed HMTBa had higher daily gain and improved feed efficiency than DLM during the grower phase (p 0.05). Chicks fed low-CP diets grew slower, used feed less efficiently during the grower, finisher phase and overall. On d 42, regardless of dietary CP levels, birds fed HMTBa had higher carcass weights, breast and thigh weights than DLM-fed birds (p
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- 2007
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10. Determining the Methionine Activity of Mintrex Organic Trace Minerals in Broiler Chicks by Using Radiolabel Tracing or Growth Assay
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J. D. Richards, J. A. Hume, C. A. Atwell, C. D. Knight, Julia J. Dibner, and G. F. Yi
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Male ,Methionine ,Duodenum ,Chemistry ,Inorganic chemistry ,Broiler ,General Medicine ,Animal Feed ,Diet ,Trace Elements ,Bioavailability ,chemistry.chemical_compound ,Jejunum ,Trace Minerals ,Liver ,Isotope Labeling ,Dietary Supplements ,Animals ,Animal Nutritional Physiological Phenomena ,Animal Science and Zoology ,Muscle, Skeletal ,Chickens ,Pancreas ,Nuclear chemistry - Abstract
Mintrex Zn, Mintrex Cu, and Mintrex Mn organic trace minerals contain 16% Zn, 15% Cu, and 13% Mn with 80, 78, and 76% 2-hydroxy-4-(methylthio)butanoic acid (HMTBA) by weight as the organic ligand, respectively. Our objective was to determine if HMTBA from Mintrex was fully available as a Met source. In experiment 1, thirty-six broilers (7 to 10 d old) were orally gavaged with methyl-(14)C-labeled HMTBA, either as free HMTBA (Alimet feed supplement) or Zn bis(-2-hydroxy-4-methylthiobutyrate) (Mintrex Zn). Radiolabel incorporation from either source into protein was measured as a marker of bioavailable Met activity. Results demonstrated that the HMTBA from Mintrex Zn was equally available as free HMTBA to support protein synthesis. In experiment 2, five hundred seventy-six 1-d-old broilers were allotted to 12 dietary treatments (TRT) for a 21-d growth assay. A TSAA-deficient diet containing 0.70% total TSAA (TRT 1) was supplemented with 0.05, 0.10, 0.15, and 0.20% free HMTBA (TRT 2 to 5) to establish the standard Met response curve. Treatment 6 was analogous to TRT 2 but had an additional 160 ppm Zn, 80 ppm Cu, and 160 ppm Mn as sulfates. Treatments 7 to 12 were identical to TRT 2 but supplemented with 40 or 160 ppm Zn from Mintrex Zn, 20 or 80 ppm Cu from Mintrex Cu, or 40 or 160 ppm Mn from Mintrex Mn, respectively. For TRT 1 through 6, growth performance increased due to increasing Met addition (P < 0.01) but not to increasing inorganic trace minerals. For Mintrex Zn, Cu, and Mn (TRT 7 to 12), there was a linear increase in cumulative gain:feed ratio (P < 0.04), and for Mintrex Zn and Mn, there was a linear increase in cumulative gain (P < 0.03) to increasing Mintrex addition. A 1-slope broken-line model was used to calculate bioavailable Met activity from Mintrex for comparison with actual intake values. Results indicated that HMTBA from Mintrex was fully available as a Met source.
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- 2007
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11. Evidence for 2-Hydroxy-4(Methylthio) Butanoic Acid and dl-Methionine Having Different Dose Responses in Growing Broilers
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C. D. Knight, Mercedes Vazquez-Anon, Thomas R. Hampton, S Ritcher, Ricardo Gonzalez-Esquerra, Jeffre D. Firman, and E Saleh
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Male ,Random allocation ,Dose-Response Relationship, Drug ,Methionine metabolism ,business.industry ,Nutritional Requirements ,Broiler ,Nutritional Status ,Nutritional status ,General Medicine ,Weight Gain ,Meat and bone meal ,Biotechnology ,Random Allocation ,Methionine ,Animal science ,Animals ,Animal Nutritional Physiological Phenomena ,Animal Science and Zoology ,business ,Chickens ,DL-methionine ,Mathematics - Abstract
The objective of this study was to compare the gain-response curve to dietary levels of 2-hydroxy-4(methylthio) butanoic acid (HMTBA) and DL-Met (DLM) across 4 floor pen trials in which different diets were used. Six replicates of 38 or 41 birds per pen (trials 1 to 2 and 3 to 4, respectively) were used in a 2 x 3 factorial arrangement. A control with 12 replicates was also included. The 2 Met sources were fed at 3 equimolar levels equally spaced, with the highest level added at requirements from 1 to 48, 49, 43, or 49 d for trials 1, 2, 3, and 4, respectively. Commercial-type TSAA-deficient control diets contained sorghum, wheat, corn, or corn plus meat and bone meal for trials 1, 2, 3, and 4, respectively. Performance improved at all times for most parameters after supplementing with HMTBA or DLM (P0.05). No differences were found in the birds fed HMTBA or DLM at any age and trial (P0.05), except for trial 1, in which 17-d-old birds performed better when fed HMTBA than DLM (P0.05). In each trial, linear, quadratic, and exponential regressions were conducted upon the gain response of birds fed HMTBA and DLM separately. Equations with better goodness of fit were used to compare the estimated gain responses to feeding HMTBA vs. DLM. In 3 trials, the shape of the gain-response curve differed when feeding HMTBA vs. DLM. In trials 3 and 4, feeding HMTBA at commercial levels resulted in greater gain responses than DLM (P0.05), whereas, in trials 2 and 4, at very deficient levels, DLM-fed birds outperformed those fed HMTBA (P0.05). When the 4 trials were combined, the dose-response curve with the best goodness of fit was linear for HMTBA and quadratic for DLM. It can be concluded that the 2 Met sources have a different dose-response form, HMTBA could outperform DLM at commercial levels, and DLM could outperform HMTBA at deficient levels.
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- 2006
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12. Estimation of the true ileal digestible lysine and sulfur amino acid requirement and comparison of the bioefficacy of 2-hydroxy-4-(methylthio)butanoic acid and DL-methionine in eleven- to twenty-six-kilogram nursery pigs1,2
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G. F. Yi, P. Srichana, K. R. Perryman, C. D. Knight, B. W. Ratliff, G. L. Allee, and A. M. Gaines
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Methionine ,Relative efficacy ,Kilogram ,Chemistry ,Sulfur Amino Acids ,Animal feed ,Stereochemistry ,Lysine ,General Medicine ,chemistry.chemical_compound ,Animal science ,Genetics ,Animal Science and Zoology ,Digestion ,DL-methionine ,Food Science - Abstract
Three experiments were conducted to determine the true ileal digestible (TID) Lys and sulfur AA (SAA) requirement and to compare the bioefficacy of 2-hydroxy-4-(methylthio)butanoic acid (HMTBA) and dl-MET as Met sources in nursery pigs. Experiment 1 included 2 studies: 1 was 662 nursery pigs (Triumph 4 x PIC C22; initial BW 12.2 +/- 0.18 kg) allotted to 1 of 5 dietary treatments with TID Lys concentrations ranging from 1.10 to 1.50%; and the second study was 665 nursery pigs (Triumph 4 x PIC C22; initial BW 12.3 +/- 0.18 kg) allotted to 1 of 5 dietary treatments with TID SAA concentration ranging from 0.63 to 0.90%. In Exp. 2, 638 nursery pigs (Triumph 4 x PIC C22; initial BW 13.0 +/- 0.16 kg) were allotted to the same 5 SAA dietary treatments as in Exp. 1. In Exp. 3, 1,232 pigs (Triumph 4 x PIC C22; initial BW 11.0 +/- 0.30 kg) were allotted to 1 of 7 dietary treatments. The basal diet (diet 1) was supplemented with high concentrations of synthetic AA but no Met; this resulted in a dietary concentration of TID Lys of 1.30% and TID SAA of 0.50%. Diets 2 to 7 were the basal diet supplemented with 3 equimolar levels of HMTBA or dl-MET to provide TID SAA concentrations of 0.56, 0.62, and 0.68%, respectively. In Exp. 1, increasing TID Lys from 1.10 to 1.50% increased ADG (quadratic; P < 0.05) and improved G:F (linear; P < 0.002). The pooled data of Exp. 1 (SAA study) and Exp. 2 indicated that increasing TID SAA from 0.63 to 0.90% increased ADG (quadratic; P < 0.01) and improved G:F (quadratic; P < 0.01). Various methods of analyzing the growth response surface indicated that the optimal TID Lys concentration ranged from 1.28 to 1.32% for ADG (Exp. 1), and the optimal TID SAA concentration ranged from 0.73 to 0.77% for ADG and 0.80 to 0.83% for G:F (pooled Exp. 1 and 2), respectively. In Exp. 3, increasing TID SAA concentrations from 0.50 to 0.68% resulted in a linear improvement of ADG (P < 0.001), ADFI (P < 0.05), and G:F (P < 0.001). The best fit comparison of HMTBA and dl-MET was determined by the Schwartz Bayesian Information Criteria index, which indicated the average relative efficacy of HMTBA vs. dl-MET was 111%, with 95% confidence interval of 83 to 138%, within the range of TID SAA tested. Thus, the TID Lys and SAA requirements of modern lean-genotype pigs from 11- to 26-kg were greater than the 1998 NRC recommendations, and both HMTBA and dl-MET as Met sources can supply equimolar amounts of Met activity.
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- 2006
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13. Effect of Supplementing 2-Hydroxy-4-(Methylthio) Butanoic Acid and DL-methionine in Corn-soybean-cottonseed Meal Diets on Growth Performance and Carcass Quality of Broilers
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C. D. Knight, G. F. Yi, Yulan Liu, G. L. Song, M. Vazquez-Anon, J. W. Huang, and Yongqing Hou
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Meal ,Methionine ,digestive, oral, and skin physiology ,Broiler ,food and beverages ,Factorial experiment ,Biology ,Feed conversion ratio ,chemistry.chemical_compound ,Starter ,chemistry ,medicine ,Animal Science and Zoology ,Food science ,medicine.symptom ,Cottonseed meal ,Weight gain ,Food Science - Abstract
This experiment was conducted to compare the effects of feeding DL-2-hydroxy-4-(methylthio)butanoic acid (HMTBA) and DL-methionine (DLM) supplemented corn-soybean-cottonseed meal diets on growth performance, carcass composition, and muscle color of broilers. The trial was designed as a 2×3×2 factorial experiment, including two methionine (Met) sources (HMTBA and DLM), three equimolar graded levels of Met supplementation (i.e., 0.08, 0.16, and 0.24% in the starter diet and 0.07, 0.14, and 0.21% in the grower and finisher diets, respectively), and two sexes (male and female). Additionally, one basal diet for each sex was formulated to be limiting in Met to test the dosage response of increasing supplemental Met levels. Four hundred and twenty 10-d-old broilers were randomly allotted to 14 treatments (seven each for males and females), with five replicate pens per treatment and six chicks per pen. There was no difference (p>0.05) between the two Met sources in growth performance and muscle deposition of broilers throughout the whole experimental period (d 10 to 49). With the increasing Met supplementation levels, average daily gain was increased (quadratic; p
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- 2006
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14. Estimation of the ideal ratio of true ileal digestible sulfur amino acids:lysine in 8- to 26-kg nursery pigs1,2
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B. W. Ratliff, D. C. Kendall, G. F. Yi, K. R. Perryman, C. D. Knight, P. Srichana, G. L. Allee, and A. M. Gaines
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Meal ,Animal science ,Biochemistry ,Chemistry ,Sulfur Amino Acids ,Lysine ,Genetics ,Lysine metabolism ,Animal Science and Zoology ,General Medicine ,Body weight ,Digestion ,Food Science - Abstract
Four experiments were conducted to determine the ideal ratio of true ileal digestible (TID) sulfur AA to Lys (SAA:LYS) in nursery pigs at two different BW ranges using both DL-Met and 2-hydroxy-4-(methylthio)-butanoic acid (HMTBA) as Met sources. In Exp. 1, 1,549 nursery pigs (Triumph 4 x PIC Camborough 22; initial BW 8.3 +/- 0.08 kg) were allotted to one of nine dietary treatments. The basal diet (Diet 1) was a semicomplex corn-soybean meal-based diet (1.32% TID Lys) with no supplemental HMTBA or DL-Met (47.7% TID SAA:LYS). Diets 2 to 9 consisted of the basal diet supplemented with four equimolar levels of DL-Met or HMTBA (52.7, 57.7, 62.7, and 67.7% TID SAA:LYS). In Exp. 2, 330 nursery pigs (Triumph 4 x PIC Camborough 22; initial BW 11.4 +/- 0.10 kg) were allotted to one of nine dietary treatments. The basal diet (Diet 1) was a corn-soybean meal-based diet (1.15% TID Lys) with no supplemental HMTBA or DL-Met (49% TID SAA:LYS). Diets 2 to 9 consisted of the basal diet supplemented with four equimolar levels of DL-Met or HMTBA (54, 59, 64, and 69% TID SAA:LYS). In Exp. 3, 1,544 nursery pigs (Triumph 4 x PIC Camborough 22; initial BW 12.4 +/- 0.13 kg) were allotted to one of nine dietary treatments as in Exp. 2. In Exp. 4, 343 nursery pigs (Genetiporc; initial BW 12.8 +/- 0.56 kg) were allotted to one of six dietary treatments. The basal diet (Diet 1) was a corn-soybean meal-based diet (1.05% TID Lys) with no supplemental DL-Met (49% TID SAA:LYS). Diets 2 to 5 consisted of the basal diet supplemented with four levels of DL-Met (54, 59, 64, and 69% TID SAA:LYS), and Diet 6 was the basal diet supplemented with one equimolar level of HMTBA to satisfy 59% TID SAA:LYS ratio. In all experiments, increasing the TID SAA:LYS ratio resulted in quadratic improvements in ADG (P < or = 0.09) and G:F (P < or = 0.05). Three different methods were used to estimate the optimal TID SAA:LYS ratio for each experiment. The two-slope broken-line regression model, x-intercept value of the broken-line and quadratic curve, and 95% of upper asymptote across the four experiments indicated that the average optimal TID SAA:LYS ratios were 59.3, 60.1, and 57.7% for ADG and 60.6, 61.7, and 60.1% for G:F, respectively. Thus, the optimal TID SAA:LYS ratio for 8- to 26-kg pigs based on the average value of these three estimates was 59.0% for ADG and 60.8% for G:F.
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- 2005
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15. Mass spectrometry in the exploration of Mars
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Catherine Fenselau, Richard Caprioli, A. O. Nier, W. B. Hanson, A. Seiff, M. B. Mcelroy, N. W. Spencer, R. J. Duckett, T. C. D. Knight, W. S. Cook, K. Biemann, J. Oro, P. Toulmin, L. E. Orgel, D. M. Anderson, P. G. Simmonds, D. Flory, A. V. Diaz, D. R. Rushneck, J. A. Biller, and Tobias Owen
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Chemistry ,Mars Exploration Program ,Mass spectrometry ,Spectroscopy ,Astrobiology - Published
- 2003
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16. Efficacy of an equine joint supplement, and the synergistic effect of its active ingredients (chelated trace minerals and natural eggshell membrane), as demonstrated in equine, swine, and an osteoarthritis rat model
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Jenea Lunnemann, Joseph L. Evans, C. D. Knight, Karen Wedekind, Nancy K Keith, Laura L Greiner, Cindy A Atwell, Roy H Sorbert, Thomas R. Hampton, Josie A Coverdale, Robert Harrell, and Junmei Zhao
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Active ingredient ,Veterinary medicine ,Open Access Animal Physiology ,Trace Minerals ,business.industry ,Rat model ,Medicine ,Food science ,Osteoarthritis ,Eggshell membrane ,business ,medicine.disease - Abstract
Karen J Wedekind,1 Josie A Coverdale,2 Thomas R Hampton,1 Cindy A Atwell,1 Roy H Sorbet,3 Jenea Lunnemann,1 Robert J Harrell,1 Laura Greiner,4 Nancy K Keith,5 Joseph L Evans,1 Junmei Zhao,1 Chris D Knight1 1Novus International, Inc., St Charles, MO, USA; 2Department of Animal Science, Texas A&M University, College Station, TX, USA; 3Certus International, Inc., Chesterfield, MO, USA; 4Innovative Swine Solution, Carthage, IL, USA; 5Keith Associates, Springfield, MO, USA Purpose: To determine the efficacy of an equine joint supplement STEADFAST® and/or its active components (Natural Eggshell Membrane [NEM®] and chelated trace minerals [CTM]) in horses with naturally occurring osteoarthritis or in a chemically induced osteoarthritis rat model. In addition, the efficacy of CTM vs inorganic trace minerals (ITM) (Zn, Mn, and Cu) in reducing culling rates in swine was evaluated. Methods: Horse trial: 16 mature horses with existing lameness were fed test joint supplement or placebo for 42 d. Lameness (American Association Equine Practitioner scoring system), serum biomarkers (C-terminal cross-linked telopeptide type II collagen [CTXII] and N-propeptide type IIA collagen [PIIANP]), and synovial fluid WBC were assessed biweekly. Rat trial: A chemically induced (monoiodoacetate [MIA]) osteoarthritis rat model was utilized. Rats were fed either negative control or joint supplement at 1% or 2% inclusion in Exp 1 (n=54) for 56 d. In Exp 2 (n=48), rats were fed control, NEM, CTM, or NEM + CTM for 42 d (28 d prefeed + Exp period). Rats were injected with MIA d29. Pain, knee swelling, and CTXII were measured post-MIA injection. Sow trial: Two farms with 6,400 sows each were fed ITM or 50:50 blend of ITM:CTM at equal TM levels for ~3 yr. Treatments were initiated at weaning through entry into the breeding herd. Sows remained on treatment until culled. Sow retention rate and reasons for removal were measured. Results: In horse and rat trials, chondromodulating effects of the joint supplement were observed: increased cartilage synthesis (PIIANP) or decreased cartilage degradation (CTXII). CTM + NEM decreased pain, swelling, and CTXII, compared to control and/or CTM or NEM alone (P30% with CTM supplementation (P
- Published
- 2015
17. Further evaluation of waves and turbulence encountered by the Galileo Probe during descent in Jupiter's atmosphere
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John D. Mihalov, Donn B. Kirk, Tony C. D. Knight, and Alvin Seiff
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Jupiter ,Atmosphere ,Physics ,Geophysics ,Gravitational wave ,Turbulence ,Galileo Probe ,Atmospheric instability ,General Earth and Planetary Sciences ,Aerodynamics ,Descent (aeronautics) ,Geodesy - Abstract
Data from the Galileo Probe in Jupiter descent indicated descent velocity oscillations as large as ±5 m/s on a height scale of a few km, which suggested gravity waves in the atmosphere between 4 and 20 bars (Seiff et al., 1998), an important observation for atmospheric stability and dynamics. But we now find these velocity fluctuations to be inconsistent with simultaneous measurements of mean accelerations, which were relatively steady. This conflict is resolved in favor of the accelerometers. The velocity fluctuations can be explained from digital uncertainties in the slow rate of pressure rise. However, the accelerometers did record higher frequency perturbations of up to 0.1g. Attributed to turbulence, these imply turbulent velocities from 0.3 to 5 m/s at scales of 10 to 40 m. However, they were at least partly a result of unsteady parachute aerodynamics.
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- 1999
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18. A specific member of the Cab multigene family can be efficiently targeted and disrupted in the moss Physcomitrella patens
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M. Chakhparonian, C. Ivascu, Didier G. Schaefer, Vincenzo E. A. Russo, David J. Cove, Jean-Pierre Zryd, A. H. Hofmann, C. D. Knight, and Antonio C. Codón
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DNA, Plant ,Physcomitrella ,Molecular Sequence Data ,Genes, Plant ,Physcomitrella patens ,Polymerase Chain Reaction ,Transformation, Genetic ,Sequence Homology, Nucleic Acid ,Gene cluster ,Genetics ,Gene family ,Coding region ,Amino Acid Sequence ,Molecular Biology ,Gene ,Base Sequence ,biology ,food and beverages ,Gene targeting ,Sequence Analysis, DNA ,biology.organism_classification ,Bryopsida ,Blotting, Southern ,Multigene Family ,Mutagenesis, Site-Directed ,Homologous recombination - Abstract
The analysis of phenotypic change resulting from gene disruption following homologous recombination provides a powerful technique for the study of gene function. This technique has so far been difficult to apply to plants because the frequency of gene disruption following transformation with constructs containing DNA homologous to genomic sequences is low (0.01 to 0.1%). It has recently been shown that high rates of gene disruption (up to 90%) can be achieved in the moss Physcomitrella patens using genomic sequences of unknown function. We have used this system to examine the specificity of gene disruption in Physcomitrella using a member of the Cab multigene family. We have employed the previously characterised Cab gene ZLAB1 and have isolated segments of 13 other closely related members of the Cab gene family. In the 199-bp stretch sequenced, the 13 new members of the Cab family show an average of 8.5% divergence from the DNA sequence of ZLAB1. We observed 304 silent substitutions and 16 substitutions that lead to a change in the amino acid sequence of the protein. We cloned 1029 bp of the coding region of ZLAB1 (including 177 of the 199 bp with high homology to the 13 new Cab genes) into a vector containing a selectable hygromycin resistance marker, and used this construct to transform P. patens. In three of nine stable transformants tested, the construct had inserted in, and disrupted, the ZLAB1 gene. There was no discernible phenotype associated with the disruption. We have therefore shown that gene disruption is reproducible in P. patens and that the requirement for sequence homology appears to be stringent, therefore allowing the role of individual members of a gene family to be analysed in land plants for the first time.
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- 1999
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19. Early Feeding and Development of the Immune System in Neonatal Poultry
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F. J. Ivey, M. L. Kitchell, C. D. Knight, A. C. Downs, Julia J. Dibner, and C. A. Atwell
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Immunoglobulin A ,animal structures ,Animal science ,Immune system ,Starter ,biology ,Nutritional content ,biology.protein ,Broiler ,Germinal center ,Initial treatment ,Animal Science and Zoology ,Early feeding - Abstract
The objective of this research was to evaluate the effect of early feeding on the development of the immune system in broiler chicks. A hydrated nutritional supplement formulated specifically for the first 2 to 3 days of post-hatch life was provided to the chicks on the day of hatch and the 2 subsequent days. The nutritional content of this supplement was optimized to achieve maximum performance at 6 wk following ad libitum consumption of starter feed and water. Control hatchlings received neither feed nor water. After the initial treatment, all birds were fed the same corn-soy diet ad libitum. Immune development was assessed by measuring bursa weight, biliary immunoglobulin A (IgA) levels, appearance of germinal centers in the cecal tonsils, and resistance to an oral challenge with coccidial oocysts. Data indicate that provision of the optimum balance of nutrients immediately after hatch result in heavier bursa weights, earlier appearance of biliary IgA and germinal centers, and an improved resistance to disease challenge.
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- 1998
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20. The clouds of Jupiter: Results of the Galileo Jupiter Mission Probe Nephelometer Experiment
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K. Rages, Boris Ragent, Tony C. D. Knight, Philip Avrin, Gerald W. Grams, P. Yanamandra-Fisher, David S. Colburn, and Glenn S. Orton
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Atmospheric Science ,Particle number ,Galileo Probe ,Soil Science ,Astrophysics ,Aquatic Science ,Oceanography ,Jupiter ,Atmosphere ,chemistry.chemical_compound ,Exploration of Jupiter ,Geochemistry and Petrology ,Ammonium hydrosulfide ,Earth and Planetary Sciences (miscellaneous) ,Astrophysics::Galaxy Astrophysics ,Earth-Surface Processes ,Water Science and Technology ,Physics ,Ecology ,Nephelometer ,Paleontology ,Astronomy ,Forestry ,Geophysics ,chemistry ,Space and Planetary Science ,Particle ,Astrophysics::Earth and Planetary Astrophysics - Abstract
The results of the nephelometer experiment conducted aboard the probe of the Galileo mission to Jupiter are presented. The tenuous clouds and sparse particulate matter in the relatively particle-free 5-μm “hot spot” region of the probe's descent were documented from about 0.46 bar to about 12 bars. Three regions of apparent coherent structure were noted, in addition to many indications of extremely small particle concentrations along the descent path. From the first valid measurement at about 0.46 bar down to about 0.55 bar, a feeble decaying lower portion of a cloud, corresponding with the predicted ammonia particle cloud, was encountered. A denser, but still very modest, particle structure was present in the pressure regime extending from about 0.76 bar to a distinctive base at 1.34 bars and is compatible with the expected ammonium hydrosulfide cloud. No massive water cloud was encountered, although below the second structure, a small, vertically thin layer at about 1.65 bars may be detached from the cloud above, but may also be water condensation, compatible with reported measurements of water abundance from other Galileo Mission experiments. A third small signal region, extending from about 1.9 to 4.5 bars, exhibited quite weak but still distinctive structure and, although the identification of the light scatterers in this region is uncertain, may also be a water cloud, perhaps associated with lateral atmospheric motion and/or reduced to a small mass density by atmospheric subsidence or other causes. Rough descriptions of the particle size distributions and cloud properties in these regions have been derived, although they may be imprecise because of the small signals and experimental difficulties. These descriptions document the small number densities of particles, the moderate particle sizes, generally in the slightly submicron to few micron range, and the resulting small optical depths, mass densities due to particles, column particle number loading, and column mass loading in the atmosphere encountered by the Galileo probe during its descent.
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- 1998
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21. Thermal structure of Jupiter's atmosphere near the edge of a 5-μm hot spot in the north equatorial belt
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T. C. D. Knight, Richard E. Young, David H. Atkinson, Gerald Schubert, Robert C. Blanchard, John D. Mihalov, Leslie A. Young, Donn B. Kirk, Frank S. Milos, and Alvin Seiff
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Atmospheric Science ,Ecology ,Atmospheric wave ,Atmosphere of Jupiter ,Galileo Probe ,Paleontology ,Soil Science ,Forestry ,Aquatic Science ,Oceanography ,Atmospheric sciences ,Atmosphere ,Jupiter ,Geophysics ,Space and Planetary Science ,Geochemistry and Petrology ,Earth and Planetary Sciences (miscellaneous) ,Tropopause ,Stratosphere ,Geology ,Earth-Surface Processes ,Water Science and Technology ,Exosphere - Abstract
Thermal structure of the atmosphere of Jupiter was measured from 1029 km above to 133 km below the 1-bar level during entry and descent of the Galileo probe. The data confirm the hot exosphere observed by Voyager (∼900 K at 1 nanobar). The deep atmosphere, which reached 429 K at 22 bars, was close to dry adiabatic from 6 to 16 bars within an uncertainty ∼0.1 K/km. The upper atmosphere was dominated by gravity waves from the tropopause to the exosphere. Shorter waves were fully absorbed below 300 km, while longer wave amplitudes first grew, then were damped at the higher altitudes. A remarkably deep isothermal layer was found in the stratosphere from 90 to 290 km with T ∼ 160 K. Just above the tropopause at 260 mbar, there was a second isothermal region ∼25 km deep with T ∼ 112 K. Between 10 and 1000 mbar, the data substantially agree with Voyager radio occultations. The Voyager 1 equatorial occultation was similar in detail to the present sounding through the tropopause region. The Voyager IRIS average thermal structure in the north equatorial belt (NEB) approximates a smoothed fit to the present data between 0.03 and 400 mbar. Differences are partly a result of large differences in vertical resolution but may also reflect differences between a hot spot and the average NEB. At 15 4 bars, probe descent velocities derived from the data are consistently unsteady, suggesting the presence of large-scale turbulence or gravity waves. However, there was no evidence of turbulent temperature fluctuations >0.12 K. A conspicuous pause in the rate of decrease of descent velocity between 1.1 and 1.35 bars, where a disturbance was also detected by the two radio Doppler experiments, implies strong vertical flow in the cloud seen by the probe nephelometer. At p < 0.6 bar, measured temperatures were ∼3 K warmer than the dry adiabat, possible evidence of radiative warming. This could be associated with a tenuous cloud detected by the probe nephelometer above the 0.51 bar level. For an ammonia cloud to form at this level, the required abundance is ∼0.20 × solar.
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- 1998
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22. Studying plant development in mosses: the transgenic route
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C. D. Knight
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Genetics ,Transformation (genetics) ,Ceratodon purpureus ,biology ,Physiology ,Extrachromosomal DNA ,Transgene ,Mutant ,Plant Science ,Genetically modified crops ,Physcomitrella patens ,biology.organism_classification ,Gene - Abstract
The current status of transgenic studies in mosses is reviewed with particular attention being given to the mosses Physcomitrella patens and Ceratodon purpureus. This paper reviews the advantages of using mosses as models for higher plants in the study of plant development, and includes developmental processes, already partially characterized at the genetic level by mutant analysis, for which transgenic studies may be applicable. The P. patens transformation process is being studied in this laboratory and details are given for a class of transformants which contain extrachromosomal plasmid DNA. Publications which present the nucleic acid and/or protein sequence for nuclear, chloroplast and mitochondrial genes are reviewed. Areas of research in which transgenic studies promise to complement existing cell biological and physiological approaches are discussed. These include the measurement of calcium levels in mutant and wild-type transformants expressing the apoaequorin gene and a role for phytochrome gene expression in the establishment of polarity.
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- 1994
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23. Performance, carcass composition, and blood hormones and metabolites of finishing pigs treated with porcine somatotropin in hot and cold environments
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H. B. Hedrick, B. A. Becker, Clifton A. Baile, C D Knight, J J Veenhuizen, and G. W. Jesse
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Male ,Meat ,Swine ,Calorimetry ,Fatty Acids, Nonesterified ,Weight Gain ,Blood Urea Nitrogen ,Body Temperature ,Protein content ,Eating ,Animal science ,Insulin-Like Growth Factor II ,Reduced fat ,Genetics ,Animals ,Insulin-Like Growth Factor I ,Carcass composition ,Chemistry ,Respiration ,Temperature ,Rectal temperature ,General Medicine ,Recombinant Proteins ,Thyroxine ,Adipose Tissue ,Growth Hormone ,Body Composition ,Triiodothyronine ,Animal Science and Zoology ,Composition (visual arts) ,Respiration rate ,Body Temperature Regulation ,Food Science ,Hormone - Abstract
Two experiments were conducted to assess the ability for recombinant porcine somatotropin (rpST)-treated pigs to perform and cope with the demands of hot and cold environments. In the first experiment, finishing pigs were exposed to either a thermoneutral (TN; 18 to 21 degrees C) or a hot environment (H; 27 to 35 degrees C) for 35 d. In the second experiment, pigs were exposed to a TN or cold environment (C; 5 to 15 degrees C). The rpST delivered by a 6-wk prolonged-release system had no effect on ADG, whereas both H and C reduced ADG by 29.4 and 11.8%, respectively. In the first experiment, rpST-treated pigs consumed 17.6% less feed than control pigs, whereas rpST-treated pigs in H consumed 24.4% less feed than rpST-treated pigs in TN. Overall feed/gain ratios through the first 4 wk of both studies were improved by 21.8 and 14%, respectively, by rpST (P < .05) and were 24.3% poorer in C (P < .05) than in H. The changes in blood concentrations of pST, IGF-I, and IGF-II associated with rpST were not influenced by the different environments. Total body composition of rpST-treated pigs had increased amounts of protein (P < .05) and decreased amounts of fat (P < .05); H further reduced fat (P < .05). The C resulted in reduced protein content (P < .05). No evidence of thermal imbalance due to rpST was found as assessed by rectal temperature, respiration rate, and heat production estimated by indirect calorimetry and chemical analysis.
- Published
- 1993
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24. Comparison of hydrated sodium calcium aluminosilicate and yeast cell wall on counteracting aflatoxicosis in broiler chicks
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R. B. Shirley, Mercedes Vazquez-Anon, M. Kitchell, F. Uraizee, Junmei Zhao, J. D. Dibner, M. Officer, and C. D. Knight
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Sodium ,Hydrated Sodium Calcium Aluminosilicate ,chemistry.chemical_element ,Food Contamination ,Calcium ,Animal science ,Blood serum ,Aflatoxins ,Cell Wall ,Yeasts ,medicine ,Animals ,Poultry Diseases ,Chromatography ,Broiler ,Mycotoxicosis ,General Medicine ,Animal Feed ,Diet ,Blood chemistry ,chemistry ,Liver ,Dietary Supplements ,Alkaline phosphatase ,Animal Science and Zoology ,Aluminum Silicates ,Animal Nutritional Physiological Phenomena ,medicine.symptom ,Weight gain ,Chickens - Abstract
The objective of this research was to determine the efficacy of 2 types of adsorbents [hydrated sodium calcium aluminosilicates (HSCAS) vs. a combination of clay and yeast cell wall] in preventing aflatoxicosis in broilers. A total of 275 one-day-old birds were randomly divided into 11 treatments, with 5 replicate pens per treatment and 5 chicks per pen. The 11 treatments included 3 diets without any adsorbent containing either 0, 1, or 2 mg/kg of aflatoxin B1 (AFB1) plus 8 additional treatments employing 2 dietary levels of AFB1 (1 or 2 mg/kg), 2 different adsorbents [Solis (SO) and MTB-100 (MTB)], and 2 different levels of each absorbent (0.1 and 0.2%) in a 2×2×2 factorial arrangement. Solis is a mixture of different HSCAS and MTB is a combination of clay and yeast cell wall. Feed and water were provided ad libitum throughout the 21-d study period. Body weight gain and feed intake were depressed and relative liver weight was increased in chicks fed AFB1 compared with the positive control (P
- Published
- 2010
25. Effect of a hot environment on performance, carcass characteristics, and blood hormones and metabolites of pigs treated with porcine somatotropin
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H. B. Hedrick, Clifton A. Baile, G. W. Jesse, Frances C. Buonomo, B. A. Becker, and C D Knight
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Blood Glucose ,Male ,Hot Temperature ,Meat ,Swine ,Biology ,Weight Gain ,Feed conversion ratio ,Blood Urea Nitrogen ,Body Temperature ,Eating ,Random Allocation ,Animal science ,Insulin-Like Growth Factor II ,Genetics ,Animals ,Insulin-Like Growth Factor I ,Serum Albumin ,Drug Implants ,Respiration ,Humidity ,General Medicine ,Recombinant Proteins ,Growth Hormone ,Triiodothyronine ,Female ,Animal Science and Zoology ,Food Science ,Hormone - Abstract
A study was conducted to compare the effects of a single 100-mg recombinant porcine somatotropin (rpST) implant on performance, carcass characteristics, and blood hormones and metabolites of 40 finishing pigs exposed to either a thermoneutral (TN; 18 to 21 degrees C) or hot environment (H; 27 to 35 degrees C) for 28 or 35 d. Pigs in H gained at a slower rate (P less than .01) than pigs in TN. Control and rpST-treated pigs gained at similar rates in respective environments. The rpST-treated pigs consumed 13% less feed (P less than .01) than the control pigs in both environments, and pigs in H consumed 19% less feed (P less than .01) than pigs in TN. Feed efficiency for rpST-treated pigs was 15% better (P less than .01) than that for control pigs; environment had no effect on feed efficiency. When slaughtered, pigs treated with rpST had less (P less than .01) leaf fat and less (P less than .01) 10th rib backfat than control pigs. Pigs in H had a lower (P less than .01) final BW and less leaf fat and backfat than pigs in TN. The rpST and H had various effects on blood hormones and metabolites. The results demonstrated that the benefits of this form of rpST treatment achieved under TN were also achieved in H with no interactions between the hormone and environment.
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- 1992
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26. Reviews
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Nigel Collins, Ann Dolan, Bob Fairbrother, Angela Dixon, John Woodcock, Sheila Turner, Carolyn A. Mulley, C. D. Knight, David Necklen, Janet Bennett, E. T. Hitchen, Jan Dick, A. E. Flaherty, Chris Atkinson, David Harding, Pat Hill-Cottingham, John A. Barker, Monica Hale, Mike Fullen, James B. Heale, Stewart M. Evans, Jonathan Cowie, Alan Morris, Adrian Twiner, Paula Williams, Heather Murray, Sarah McKenzie, Dave Dennis, Barry Meatyard, and Andrew Powell
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General Agricultural and Biological Sciences ,Education - Published
- 1991
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27. The performance and carcass composition responses of finishing swine to a range of porcine somatotropin doses in a 1-week delivery system1
- Author
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C. D. Knight, T. R. Kasser, G. H. Swenson, R. L. Hintz, M. J. Azain, R. O. Bates, T. R. Cline, J. D. Crenshaw, G. L. Cromwell, H. B. Hedrick, S. J. Jones, D. H. Kropf, A. J. Lewis, D. C. Mahan, F. M. McKeith, C. L. McLaughlin, J. L. Nelssen, J. E. Novakofski, M. W. Orcutt, and N. A. Parrett
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Longissimus muscle ,Meal ,Animal science ,Chemistry ,Genetics ,food and beverages ,Animal Science and Zoology ,General Medicine ,Delivery system ,Palatability ,Carcass composition ,Food Science - Abstract
Four experiments using 580 barrows and 580 gilts (Study 1) and seven experiments using 500 barrows and 500 gilts (Study 2) were conducted at various geographical locations in the United States to determine the dose response of a pelleted form of porcine somatotropin (pST) relative to ADG, feed/gain (F/G), and percentage of carcass protein. Average initial weights for Studies 1 and 2 were 67.6 and 72.6 kg, respectively, and four pigs/pen were slaughtered when they achieved weights of 106.5 to 111.0 kg. In Study 1, pigs were implanted subcutaneously with pelleted pST doses of 0, 12, 24, 36, or 48 mg/wk and self-fed a corn-soybean meal diet containing 13.75% CP. Study 2 included two control groups self-fed a diet containing either 13.75 or 17% CP with added lysine. The pST-treated pigs were administered 12, 24, or 36 mg/wk, and all were offered the 17% CP diet. The pST treatments in Study 1 resulted in a linear reduction (P less than .05) in average daily feed intake (ADFI) and a quadratic (P less than .05) improvement in F/G and percentage of carcass protein. The pST treatments in Study 2 resulted in a linear reduction in ADFI (P less than .05), a linear improvement in F/G, and a quadratic increase in the percentage of carcass protein (P less than .05). Average daily gain was not affected in either study with this form of pST. The greatest increase in efficiency of lean gain was observed with the 36-mg dose for both Study 1 (9.4%) and Study 2 (10.8%). In Study 1, the force required to shear cores of the longissimus muscle was increased linearly with pST treatment (P less than .05). There was a similar linear increase in Study 2 with pST treatment (P less than .05); however, there was also an effect of sex (P less than .05) on shear force (gilts greater than barrows) that was similar in magnitude to that observed for pST treatment. Differences in sensory evaluation because of pST were minor and of the same magnitude as those observed between barrows and gilts. It was therefore concluded that weekly administration of pST improved F/G and percentage of carcass protein with no detrimental effects on palatability of cooked lean pork.
- Published
- 1991
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28. The polarity of gravitropism in the moss Physcomitrella patens is reversed during mitosis and after growth on a clinostat
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C. D. Knight and David J. Cove
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Physiology ,Cell morphogenesis ,Gravitropism ,Mutant ,Plant Science ,Biology ,Physcomitrella patens ,biology.organism_classification ,Cell biology ,Botany ,Protonema ,Mitosis ,Clinostat ,Tropism - Abstract
We report two situations in which the polarity of gravitropism of single protonemal cells of the moss Physcomitrella patens is reversed. Dark-grown protonemata of wild-type P. patens grow negatively gravitropically. Time-lapse video-microscopy reveals that a temporary reversal of growth polarity occurs during mitotic division which is independent of the cells’ growth rate. A transitory reversal of growth direction is also observed when the unidirectional gravitropic stimulus is interrupted by a period of growth on a clinostat. A third situation, in which a mutant class responds by growing positively gravitropically, has been described previously (Jenkins, Courtice & Cove, 1986). These observations are discussed in terms of possible mechanisms for cell morphogenesis and tropic growth.
- Published
- 1991
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29. A multiple regression model approach to contrast the performance of 2-hydroxy-4-methylthio butanoic acid and DL-methionine supplementation tested in broiler experiments and reported in the literature
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Mercedes Vazquez-Anon, I. G. Yi, C. D. Knight, D. Kratzer, and Ricardo Gonzalez-Esquerra
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Male ,Databases, Factual ,Weight Gain ,Feed conversion ratio ,Models, Biological ,Animal science ,Methionine ,Linear regression ,medicine ,Animals ,DL-methionine ,Mathematics ,Control treatment ,Dose-Response Relationship, Drug ,Broiler ,Contrast (statistics) ,Regression analysis ,General Medicine ,Dietary Supplements ,Multivariate Analysis ,Animal Science and Zoology ,Animal Nutritional Physiological Phenomena ,Female ,medicine.symptom ,Weight gain ,Chickens - Abstract
The purpose of this paper was to compile all available literature comparing the relative performance of 2-hydroxy-4-methylthio butanoic acid (HMTBA) with DL-methionine (DLM) in broiler chickens and using multiple regression techniques, to estimate the predicted dose responses and relative performance of the 2 Met compounds for gain and feed conversion (FC). A database was developed that contained all available broiler studies in which HMTBA and DLM were both present in the same study; weight gain was recorded; Met addition, age of birds, and duration of study were defined; and an unsupplemented control treatment was present. Sixty-two references complied with these criteria and included 100 experiments with 427 observations for HMTBA and 411 for DLM. Multiple regression analysis of the database was used to identify the experimental and dietary conditions that contributed to the gain and FC responses of each source of Met activity. All identified variables contributed similarly to each Met source prediction model and both gain and FC models described a quadratic dose response. Under the average conditions of the database, the predicted responses for gain and FC models did not significantly differ between HMTBA and DLM. However, a trend was observed (P less than or equal to 0.1) for the peak gain response for HMTBA to be numerically greater than DLM, suggesting benefits of HMTBA over DLM in the region of supplementation that is commercially relevant. The experimental and nutritional conditions that contribute to the response to HTMBA and DLM were identified and are discussed in the paper. This statistical approach provided a means to summarize the results obtained from a multitude of studies conducted over the last 5 decades and has provided a meaningful estimate of the relative performance of the 2 sources of Met activity. The lack of differences between the 2 predicted models under experimental and commercial conditions supports an overall conclusion of equal performance of DLM and HTMBA when compared on an equal molar basis.
- Published
- 2006
30. Wind speeds measured in the deep jovian atmosphere by the Galileo probe accelerometers
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T. C. D. Knight, Gerald Schubert, R. E. Young, Alvin Seiff, Donn B. Kirk, David H. Atkinson, Robert C. Blanchard, and John D. Mihalov
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Multidisciplinary ,Meteorology ,Astrophysics::High Energy Astrophysical Phenomena ,Atmosphere of Jupiter ,Galileo Probe ,Jovian ,Wind speed ,Atmosphere ,symbols.namesake ,Circulation (fluid dynamics) ,Wind shear ,Physics::Space Physics ,symbols ,Astrophysics::Solar and Stellar Astrophysics ,Doppler effect ,Physics::Atmospheric and Oceanic Physics ,Geology - Abstract
The atmosphere of Jupiter has a complex circulation which, until recently, has been observable only at the cloud tops1,2; the mechanisms driving the winds, and the nature of the interior circulation, remained unknown3. Recent analyses4,5,6 of the radio signal from the Galileo probe, obtained during its descent into the jovian atmosphere, have suggested a vigorous interior circulation below the 4-bar level. Here we report an independent measurement of the winds below the cloud tops, making use of the data obtained by the two accelerometers on the descending probe. We find evidence for two distinct wind regimes, in general agreement with the Doppler radio measurements: a region of wind shear between 1 and 4 bar, where the wind speed increases dramatically with depth; and then a region of constant high-velocity winds down to at least the 17-bar level.
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- 1997
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31. Estimation of the ideal ratio of true ileal digestible sulfur amino acids:lysine in 8- to 26-kg nursery pigs
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A M, Gaines, G F, Yi, B W, Ratliff, P, Srichana, D C, Kendall, G L, Allee, C D, Knight, and K R, Perryman
- Subjects
Amino Acids, Sulfur ,Ileum ,Swine ,Lysine ,Body Weight ,Animals ,Animal Nutritional Physiological Phenomena ,Digestion ,Animal Feed ,Diet - Abstract
Four experiments were conducted to determine the ideal ratio of true ileal digestible (TID) sulfur AA to Lys (SAA:LYS) in nursery pigs at two different BW ranges using both DL-Met and 2-hydroxy-4-(methylthio)-butanoic acid (HMTBA) as Met sources. In Exp. 1, 1,549 nursery pigs (Triumph 4 x PIC Camborough 22; initial BW 8.3 +/- 0.08 kg) were allotted to one of nine dietary treatments. The basal diet (Diet 1) was a semicomplex corn-soybean meal-based diet (1.32% TID Lys) with no supplemental HMTBA or DL-Met (47.7% TID SAA:LYS). Diets 2 to 9 consisted of the basal diet supplemented with four equimolar levels of DL-Met or HMTBA (52.7, 57.7, 62.7, and 67.7% TID SAA:LYS). In Exp. 2, 330 nursery pigs (Triumph 4 x PIC Camborough 22; initial BW 11.4 +/- 0.10 kg) were allotted to one of nine dietary treatments. The basal diet (Diet 1) was a corn-soybean meal-based diet (1.15% TID Lys) with no supplemental HMTBA or DL-Met (49% TID SAA:LYS). Diets 2 to 9 consisted of the basal diet supplemented with four equimolar levels of DL-Met or HMTBA (54, 59, 64, and 69% TID SAA:LYS). In Exp. 3, 1,544 nursery pigs (Triumph 4 x PIC Camborough 22; initial BW 12.4 +/- 0.13 kg) were allotted to one of nine dietary treatments as in Exp. 2. In Exp. 4, 343 nursery pigs (Genetiporc; initial BW 12.8 +/- 0.56 kg) were allotted to one of six dietary treatments. The basal diet (Diet 1) was a corn-soybean meal-based diet (1.05% TID Lys) with no supplemental DL-Met (49% TID SAA:LYS). Diets 2 to 5 consisted of the basal diet supplemented with four levels of DL-Met (54, 59, 64, and 69% TID SAA:LYS), and Diet 6 was the basal diet supplemented with one equimolar level of HMTBA to satisfy 59% TID SAA:LYS ratio. In all experiments, increasing the TID SAA:LYS ratio resulted in quadratic improvements in ADG (Por = 0.09) and G:F (Por = 0.05). Three different methods were used to estimate the optimal TID SAA:LYS ratio for each experiment. The two-slope broken-line regression model, x-intercept value of the broken-line and quadratic curve, and 95% of upper asymptote across the four experiments indicated that the average optimal TID SAA:LYS ratios were 59.3, 60.1, and 57.7% for ADG and 60.6, 61.7, and 60.1% for G:F, respectively. Thus, the optimal TID SAA:LYS ratio for 8- to 26-kg pigs based on the average value of these three estimates was 59.0% for ADG and 60.8% for G:F.
- Published
- 2005
32. Impact of glutamine and Oasis hatchling supplement on growth performance, small intestinal morphology, and immune response of broilers vaccinated and challenged with Eimeria maxima
- Author
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Julia J. Dibner, G. L. Allee, G. F. Yi, and C. D. Knight
- Subjects
Male ,Protozoan Vaccines ,Glutamine ,Intestinal morphology ,Biology ,Feed conversion ratio ,Interferon-gamma ,Animal science ,Immune system ,Animals ,Intestinal Diseases, Parasitic ,Hatchling ,Poultry Diseases ,Coccidiosis ,General Medicine ,Anatomy ,biology.organism_classification ,Animal Feed ,Diet ,Intestines ,Eimeria maxima ,Interleukin-2 ,Animal Science and Zoology ,Eimeria ,Female ,Chickens - Abstract
Seven hundred and twenty hatchling broilers were allotted to 12 treatment groups. Groups 1 and 2 were fasted for 48 h posthatch; groups 3 and 4 were fasted for 48 h followed by ad libitum access to a 1% glutamine (Gln) diet; groups 5 and 6 had ad libitum access to a common diet; groups 7 and 8 had access to a 1% Gln diet posthatch; groups 9 and 10 were fed regular Oasis hatchling supplement; and groups 11 and 12 were fed Oasis sprayed with 1% Gln for the first 48 h posthatch. The birds in treatment groups 2, 4, 6, 8, 10, 11, and 12 were vaccinated with Eimeria maxima posthatch, and all birds were orally challenged with high dose E. maxima on d 22. During the first 2 wk, birds in group 7 had the highest gain and feed efficiency among treatments (P0.01). Compared with birds in the nonGln groups, birds in the Gln group had higher gain, feed efficiency, and livability (P0.05). Among the Fast (groups 1 to 4), Feed (groups 5 to 8), and Oasis (groups 9 to 12) groups, birds in the Feed groups had the highest gain during d 0 to 21 (P0.01). During d 22 to 28, birds in the Fast groups had the lowest BW and livability (P0.01), and the nonvaccinated birds had lower gain and feed efficiency relative to vaccinated birds (P0.01). Birds in the Feed and Oasis groups had higher villus height (VH) of mid small intestine than Fast groups at d 2 and 7 (P0.05), and nonvaccinated birds had higher VH than vaccinated birds (P0.01) at d 7 after hatch. On d 14, there were differences in serum interferon-gamma (P0.05) levels among treatments. During d 22 to 28, vaccinated birds had lower lesion scores in the mid small intestine than nonvaccinated birds (P0.01), and birds in the Feed or Oasis groups had lower lesion scores compared with the Fast groups (P0.02). These results indicated the importance of immediate access to feed posthatch, the beneficial effects of feeding Oasis hatching supplement and Gln after hatch, as well as the necessity of the vaccination program against coccidiosis challenge.
- Published
- 2005
33. Reply: dl-2-Hydroxy-4-(Methylthio)Butanoic Acid from any Commercial Source is Fully Available as a Source of Methionine Activity
- Author
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J. D. Richards, C. D. Knight, and Julia J. Dibner
- Subjects
chemistry.chemical_compound ,Methionine ,chemistry ,Stereochemistry ,Animal Science and Zoology ,General Medicine - Published
- 2007
- Full Text
- View/download PDF
34. Structure of the Atmosphere of Jupiter: Galileo Probe Measurements
- Author
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Alvin Seiff, Gerald Schubert, Richard E. Young, T. C. D. Knight, Ulf von Zahn, Jerry Wang, Robert C. Blanchard, Donn B. Kirk, Frank S. Milos, Gerald A. Lehmacher, and John D. Mihalov
- Subjects
Physics ,Convection ,Multidisciplinary ,Atmosphere of Jupiter ,Galileo Probe ,Lapse rate ,Atmospheric sciences ,Atmosphere ,Jupiter ,Temperature gradient ,Physics::Space Physics ,Astrophysics::Earth and Planetary Astrophysics ,Physics::Atmospheric and Oceanic Physics ,Exosphere - Abstract
Temperatures and pressures measured by the Galileo probe during parachute descent into Jupiter's atmosphere essentially followed the dry adiabat between 0.41 and 24 bars, consistent with the absence of a deep water cloud and with the low water content found by the mass spectrometer. From 5 to 15 bars, lapse rates were slightly stable relative to the adiabat calculated for the observed H2/He ratio, which suggests that upward heat transport in that range is not attributable to simple radial convection. In the upper atmosphere, temperatures of >1000 kelvin at the 0.01-microbar level confirmed the hot exosphere that had been inferred from Voyager occultations. The thermal gradient increased sharply to 5 kelvin per kilometer at a reconstructed altitude of 350 kilometers, as was recently predicted. Densities at 1000 kilometers were 100 times those in the pre-encounter engineering model.
- Published
- 1996
35. The moss, Physcomitrella patens, transformed with apoaequorin cDNA responds to cold shock, mechanical perturbation and pH with transient increases in cytoplasmic calcium
- Author
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T L Wang, Anthony J. Trewavas, Marc R. Knight, A J Russell, C D Knight, and D J Cove
- Subjects
Cytoplasm ,DNA, Complementary ,Aequorin ,chemistry.chemical_element ,Calcium ,Physcomitrella patens ,chemistry.chemical_compound ,Transformation, Genetic ,Coelenterazine ,Complementary DNA ,Genetics ,Calcium metabolism ,biology ,Renilla-luciferin 2-monooxygenase ,Wild type ,Hydrogen-Ion Concentration ,biology.organism_classification ,Bryopsida ,Recombinant Proteins ,Cold Temperature ,chemistry ,Luminescent Measurements ,biology.protein ,Biophysics ,Animal Science and Zoology ,Stress, Mechanical ,Apoproteins ,Agronomy and Crop Science ,Biotechnology - Abstract
The gene for apoaequorin has been used previously to indicate cytosolic calcium changes in higher plants. Here we report the transformation of the moss Physcomitrella patens with the cDNA for apoaequorin. Stable transformants were obtained in the wild type which reconstitute the calcium-sensitive luminescent protein aequorin in vivo after incubation in coelenterazine, and continue to grow normally. The wild type responds to cold-shock (0-10 degrees C) with increases in cytosolic calcium. Mechanical perturbation, in the form of touch, also induces transient increases in cytosolic calcium. A smaller response to pH, distinct from the touch response and exhibiting different kinetics, can also be detected.
- Published
- 1996
36. The feeding value of soybeans fed to rats, chickens, catfish and dairy cattle is not altered by genetic incorporation of glyphosate tolerance
- Author
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Stephen R. Padgette, Mark W. Naylor, Bruce G. Hammond, Roy L. Fuchs, C. D. Knight, Edwin H. Robinson, John L. Vicini, and Gary F. Hartnell
- Subjects
Male ,animal structures ,Rumen ,Food Handling ,Nitrogen ,Soybean meal ,Glycine ,Medicine (miscellaneous) ,Biology ,Feed conversion ratio ,Rats, Sprague-Dawley ,Random Allocation ,Animal science ,Animals ,Lactation ,Pancreas ,Dairy cattle ,Meal ,Nutrition and Dietetics ,business.industry ,Herbicides ,Body Weight ,Broiler ,food and beverages ,biology.organism_classification ,Animal Feed ,Biotechnology ,Rats ,Ictaluridae ,Milk ,Liver ,Ictalurus ,Body Composition ,Cattle ,Female ,Soybeans ,business ,Chickens ,Nutritive Value ,Catfish - Abstract
Animal feeding studies were conducted with rats, broiler chickens, catfish and dairy cows as part of a safety assessment program for a soybean variety genetically modified to tolerate in-season application of glyphosate. These studies were designed to compare the feeding value (wholesomeness) of two lines of glyphosate-tolerant soybeans (GTS) to the feeding value of the parental cultivar from which they were derived. Processed GTS meal was incorporated into the diets at the same concentrations as used commercially; diary cows were fed 10 g/100 g cracked soybeans in the diet, a level that is on the high end of what is normally fed commercially. In a separate study, laboratory rats were fed 5 and 10 g unprocessed soybean meal 100 g diet. The study durations were 4 wk (rats and dairy cows), 6 wk (broilers) and 10 wk (catfish). Growth, feed conversion (rats, catfish, broilers), fillet composition (catfish), and breast muscle and fat pad weights (broilers) were compared for animals fed the parental and GTS lines. Milk production, milk composition, rumen fermentation and nitrogen digestibility were also compared for dairy cows. In all studies, measured variables were similar for animals fed both GTS lines and the parental line, indicating that the feeding value of the two GTS lines is comparable to that of the parental line. These studies support detailed compositional analysis of the GTS seeds, which showed no meaningful differences between the parental and GTS lines in the concentrations of important nutrients and antinutrients. They also confirmed the results of other studies that demonstrated the safety of the introduced protein, a bacterial 5-enolpyruvyl-shikimate-3-phosphate synthase from Agrobacterium sp. strain CP4.
- Published
- 1996
37. Utilization of supplemental agency nurses in an Army medical center
- Author
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F D, Anderson, J P, Maloney, C D, Knight, and B M, Jennings
- Subjects
Adult ,Male ,Attitude of Health Personnel ,Personnel Staffing and Scheduling ,Nursing Staff, Hospital ,Hospitals, Military ,Job Satisfaction ,United States ,Military Nursing ,Surveys and Questionnaires ,Workforce ,Humans ,Female ,Registries ,Morale ,Quality of Health Care - Abstract
The purpose of this study was to describe the perceived impact of supplemental agency nurses upon the quality of patient care, unit cohesiveness, and morale of permanently assigned personnel at an Army medical center. The study population consisted of 28 agency nurses and 138 permanently assigned nursing staff. The study was descriptive and exploratory in nature, utilizing the method of content analysis. Major themes that emerged from data analysis included economic, professional nursing, and patient care issues. Perceptions were that agency nurses provided the institution with necessary labor, but that the agency nurses had greater flexibility of hours and control over their practice. Permanently assigned nursing staff reported that the use of agency services hindered continuity of patient care, at times reduced the quality of care, negatively affected morale among personnel, and impacted adversely upon the time available for mission-related training.
- Published
- 1996
38. Prevention of seromas in mastectomy wounds. The effect of shoulder immobilization
- Author
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C D, Knight and F D, Griffen
- Subjects
medicine.medical_specialty ,medicine.medical_treatment ,Modified Radical Mastectomy ,law.invention ,Immobilization ,Mastectomy, Modified Radical ,Postoperative Complications ,Randomized controlled trial ,law ,medicine ,Humans ,Prospective Studies ,Range of Motion, Articular ,Prospective cohort study ,Aged ,Aged, 80 and over ,business.industry ,Shoulder Joint ,Incidence (epidemiology) ,Exudates and Transudates ,Middle Aged ,Surgery ,body regions ,Anesthesia ,Cohort ,Female ,business ,Range of motion ,Complication ,Mastectomy - Abstract
Objective: To determine if postoperative shoulder immobilization decreases the incidence of postmastectomy seromas. Design and Setting: A prospective randomized trial of three surgeons' experiences at a community hospital. Patients: Thirty-eight patients who underwent modified radical mastectomy from March 1991 through February 1993. Main Outcome Measures: Incidence of postmastectomy seromas and time required for patients to gain 110° of shoulder abduction after surgery. Results: Thirteen (72%) of 18 wounds in the maximum range of motion cohort developed seromas (72%) compared with one (6%) of 17 in the minimum range of motion cohort ( P =.0005). The average time required for the patients with maximum range of motion to gain 110° of shoulder abduction was 2.6 weeks, whereas the patients with minimum range of motion required an average of 5.0 weeks ( P =.0127). Conclusion: Postmastectomy shoulder immobilization significantly decreases the incidence of wound seromas. Although this protocol resulted in a delay in return to normal shoulder mobility, no patients sustained longterm musculoskeletal dysfunction. (Arch Surg. 1995;130:99-101)
- Published
- 1995
39. Effect of intermittent periods of high environmental temperature on broiler performance responses to sources of methionine activity
- Author
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Julia J. Dibner, C. A. Atwell, C. D. Knight, and C. W. Wuelling
- Subjects
Male ,Methionine ,Hot Temperature ,Sulfur Amino Acids ,Broiler ,Drinking ,General Medicine ,Weight Gain ,chemistry.chemical_compound ,Eating ,Animal science ,Environmental temperature ,chemistry ,Biochemistry ,Food, Fortified ,Animals ,Animal Science and Zoology ,Chickens - Abstract
The objective of these experiments was to study the effect of intermittent high temperature (IHT) on performance of broilers fed different sources of methionine activity. Two 20-d experiments were conducted in which individually caged 28-d-old cockerels were exposed to a 5-d period of constant high temperature (HT, 30 to 32 C) followed by an equal period of thermoneutral (TN) temperatures (22 C) with the 10-d temperature cycle repeated twice. Birds held at 22 C were TN controls. Grower diets contained 3,275 kcal/kg ME and 20% CP and were supplemented with either 2-hydroxy-4-(methylthio)butanoic acid (HMB, Alimet Feed Supplement) or DL-Met up to a maximum of .88 to .90% total sulfur amino acids (TSAA). In Experiment 1, gain:feed but not average daily gain was greater (P < .05) for HMB than DL-Met birds subjected to IHT (.451 vs .413, respectively), but no treatment differences were observed for TN birds. Results of Experiment 2 demonstrated a linear response to HMB and DL-Met dose in TN (P < .01); however, only HMB-supplemented birds responded similarly in IHT (P < .01). These results are consistent with lower availability of DL-Met as a result of IHT. In vitro experiments indicated that capacity for uptake of DL-Met into intestinal epithelial cells was reduced in heat-stressed birds. Uptake of D-Met was more severely affected than was L-Met. Consequently, a third performance experiment compared the ability of D-Met and L-Met to support growth under conditions of HT. The results indicated that the effect of HT on broiler performance was mediated through reduced utilization of D-Met.
- Published
- 1994
40. Effects of a porcine somatotropin implant on tissue mineral status of finishing pigs exposed to a thermoneutral or cold environment
- Author
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B. A. Becker, David R. Ledoux, Clifton A. Baile, and C D Knight
- Subjects
Male ,medicine.medical_specialty ,Swine ,Kidney ,Weight Gain ,Crossbreed ,Bone and Bones ,Animal science ,Environmental temperature ,Internal medicine ,Genetics ,medicine ,Animals ,Tissue Distribution ,Drug Implants ,Minerals ,Chemistry ,Liver and kidney ,Muscles ,Myocardium ,Temperature ,Kidney metabolism ,Myocardium metabolism ,General Medicine ,Recombinant Proteins ,Liver metabolism ,Endocrinology ,Liver ,Growth Hormone ,Animal Science and Zoology ,Female ,Implant ,Spleen ,Food Science - Abstract
An experiment was conducted with 24 crossbred (Landrace x Yorkshire x Duroc) finishing pigs (mean BW 85 kg) to study the effects of a single 100-mg recombinant porcine somatotropin (rpST) implant on the tissue mineral status of pigs exposed to either a thermoneutral (TN; 18 to 21 degrees C, 50 to 55% RH) or cold (C; 5 to 15 degrees C, 50 to 70% RH) environment until BW averaged 110 kg. The implants used in this study delivered an average 2.4 to 2.5 mg of rpST/d during the course of the study. Control pigs were implanted with a placebo. All diets were supplemented with minerals at levels that either met or exceeded the requirements of an 85-kg pig. At slaughter (mean BW 110 kg), tissues were collected and analyzed for selected macro- and microminerals. Pigs treated with rpST had higher (P < .05) Ca concentrations and total Ca in liver and kidney and higher (P < .05) Ca concentrations in muscle. Total P, Mg, Na, and K were all higher (P < .05) in the liver and kidneys of rpST-treated pigs. In general, rpST had little influence on Cu, Zn, and Fe in tissues. No consistent trend was evident in the response of tissue minerals to environmental temperature. Results indicated that pigs treated with rpST and supplemented with adequate minerals accumulated more minerals in certain tissues than did pigs not given rpST.
- Published
- 1993
41. Ovariectomy and inhibin immunoneutralization acutely increase follicle-stimulating hormone-beta messenger ribonucleic acid concentrations: evidence for a nontranscriptional mechanism
- Author
-
Margaret A. Shupnik, J A Aloi, C D Knight, Alan C. Dalkin, M Yasin, Susan E. Kirk, John C. Marshall, and Daniel J. Haisenleder
- Subjects
Messenger ribonucleic acid ,Male ,endocrine system ,medicine.medical_specialty ,Pituitary gland ,Time Factors ,Transcription, Genetic ,medicine.drug_class ,Ovariectomy ,Biology ,Follicle-stimulating hormone ,Endocrinology ,Neutralization Tests ,Reference Values ,Internal medicine ,medicine ,Animals ,Inhibins ,RNA, Messenger ,Beta (finance) ,Antiserum ,Messenger RNA ,Luteinizing Hormone ,Rats ,Kinetics ,medicine.anatomical_structure ,Glycoprotein Hormones, alpha Subunit ,Pituitary Gland ,Follicle Stimulating Hormone, beta Subunit ,Female ,Gonadotropin ,Follicle Stimulating Hormone ,hormones, hormone substitutes, and hormone antagonists ,Hormone - Abstract
After ovariectomy (ovx), FSH beta mRNA levels and serum FSH increase 2- to 3-fold within 12 h, and this persists in the presence of a GnRH antagonist. As a fall in plasma estradiol and progesterone appears to regulate FSH beta via increased GnRH secretion, it is thought that the acute (by 2 h) changes in FSH beta mRNA after ovx reflect falling levels of plasma inhibin. The current study addressed the following questions. 1) Does a reduction of circulating inhibin (via passive immunoneutralization or gonadectomy) increase FSH beta mRNA levels? 2) If so, are the acute increases in FSH beta mRNA associated with changes in the transcription rate? Adult male and female rats received 0.5 ml antiinhibin antiserum, iv, and were killed 2 or 12 h later. A second group of rats was gonadectomized; some received a GnRH antagonist and were killed at various intervals between 2 h and 7 days later. In adult males, no change in gonadotropin mRNA levels was observed after either addition of inhibin antiserum or removal of the testes. In contrast, in adult female rats, both ovx and inhibin antiserum increased FSH beta mRNA levels (2-fold) within 2 h, and a similar increase occurred in the presence of a GnRH antagonist. To determine if the increase in FSH beta resulted from increased mRNA synthesis, adult female rats were ovx, and half received a GnRH antagonist. Animals were killed 2 or 12 h later, and transcription rates were measured by nuclear run-off assay in pituitaries pooled from three rats. The transcription rate of the alpha-subunit, although not altered by ovx, was decreased in animals receiving the GnRH antagonist. Transcription of the LH beta gene was increased within 2 h after ovx, a change that was abolished by the GnRH antagonist. mRNA concentrations of either alpha or LH beta do not increase acutely after ovx, suggesting that GnRH regulates alpha and LH beta gene transcription and 12 h or more of mRNA synthesis are required to increase cytoplasmic concentrations. The FSH beta gene transcription rate was unchanged in both ovx and GnRH antagonist-treated animals, but serum FSH increased at 12 h. These data indicate that the rapid GnRH-independent increase in FSH beta mRNA levels seen immediately after ovx is not associated with altered mRNA synthesis and suggest that inhibin may also regulate FSH beta gene expression through nontranscriptional mechanisms.
- Published
- 1993
42. The Galileo Probe Atmosphere Structure Instrument
- Author
-
Alvin Seiff and T. C. D. Knight
- Subjects
biology ,Atmosphere of Jupiter ,Galileo Probe ,Venus ,Mars Exploration Program ,Atmospheric temperature ,biology.organism_classification ,Atmosphere ,Jupiter ,Atmospheric instability ,Environmental science ,Astrophysics::Earth and Planetary Astrophysics ,Physics::Atmospheric and Oceanic Physics ,Remote sensing - Abstract
The Galileo Probe Atmosphere Structure Instrument will make in-situ measurements of the temperature and pressure profiles of the atmosphere of Jupiter, starting at about 10−10 bar level, when the Probe enters the upper atmosphere at a velocity of 48 km s−1, and continuing through its parachute descent to the 16 bar level. The data should make possible a number of inferences relative to atmospheric and cloud physical processes, cloud location and internal state, and dynamics of the atmosphere. For example, atmospheric stability should be defined, from which the convective or stratified nature of the atmosphere at levels surveyed should be determined and characterized, as well as the presence of turbulence and/or gravity waves. Because this is a rare opportunity, sensors have been selected and evaluated with great care, making use of prior experience at Mars and Venus, but with an eye to special problems which could arise in the Jupiter environment. The temperature sensors are similar to those used on Pioneer Venus; pressure sensors are similar to those used in the Atmosphere Structure Experiment during descent of the Viking Landers (and by the Meteorology Experiment after landing on the surface); the accelerometers are a miniaturized version of the Viking accelerometers. The microprocessor controlled experiment electronics serve multiple functions, including the sequencing of experiment operation in three modes and performing some on-board data processing and data compression.
- Published
- 1992
- Full Text
- View/download PDF
43. Galileo Probe Nephelometer Experiment
- Author
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C. E. Carlston, C. A. Privette, J. P. Martin, T. C. D. Knight, J. G. Waring, B. Ragent, and P. Avrin
- Subjects
Physics ,Nephelometer ,Particle number ,Atmosphere of Jupiter ,Galileo Probe ,Cloud physics ,Computational physics ,law.invention ,Jupiter ,Orbiter ,law ,Particle ,Astrophysics::Earth and Planetary Astrophysics ,Remote sensing - Abstract
The objective of the Nephelometer Experient aboard the Probe of the Galileo mission is to explore the vertical structure and microphysical properties of the clouds and hazes in the atmosphere of Jupiter along the descent trajectory of the Probe (nominally from 0.1 to > 10 bars). The measurements, to be obtained at least every kilometer of the Probe descent, will provide the bases for inferences of mean particle sizes, particle number densities (and hence, opacities, mass densities, and columnar mass loading) and, for non-highly absorbing particles, for distinguishing between solid and liquid particles. These quantities, especially the location of the cloud bases, together with other quantities derived from this and other experiments aboard the Probe, will not only yield strong evidence for the composition of the particles, but, using thermochemical models, for species abundances as well. The measurements in the upper troposphere will provide ‘ground truth’ data for correlation with remote sensing instruments aboard the Galileo Orbiter vehicle. The instrument is carefully designed and calibrated to measure the light scattering properties of the particulate clouds and hazes at scattering angles of 5.8°, 16°, 40°, 70°, and 178°. The measurement sensitivity and accuracy is such that useful estimates of mean particle radii in the range from about 0.2 to 20 μ can be inferred. The instrument will detect the presence of typical cloud particles with radii of about 1.0 μ, or larger, at concentrations of less than 1 cm3.
- Published
- 1992
- Full Text
- View/download PDF
44. Genetic analysis of a mutant class of Physcomitrella patens in which the polarity of gravitropism is reversed
- Author
-
C. D. Knight, David J. Cove, and T. S. Futers
- Subjects
Genotype ,Polarity (physics) ,Genetic Linkage ,Mutant ,Gravitropism ,Mutagenesis (molecular biology technique) ,Plant Development ,Cell Separation ,Physcomitrella patens ,medicine.disease_cause ,Genetics ,medicine ,Protonema ,Molecular Biology ,Genes, Dominant ,Mutation ,biology ,Genetic Complementation Test ,Plants ,biology.organism_classification ,Complementation ,Phenotype ,Mutagenesis ,Gravitation - Abstract
In the moss Physcomitrella patens, single-cell protonemata and multicellular gametophores respond to reorientation relative to the gravity vector by growing negatively gravitropically. A mutant class in which the protonemata, but not the gametophores, respond by growing towards gravity has been identified. In this paper, we describe the isolation of additional mutants of this class. Complementation and segregation ratio analyses were carried out on these mutants, which indicate that a single gene may mutate to switch the polarity of gravitropism.
- Published
- 1991
45. Stable transformation of the moss Physcomitrella patens
- Author
-
Didier G. Schaefer, David J. Cove, Jean-Pierre Zryd, and C. D. Knight
- Subjects
Physcomitrella ,Mitosis ,Physcomitrella patens ,Polyethylene Glycols ,chemistry.chemical_compound ,Plasmid ,Transformation, Genetic ,Species Specificity ,Kanamycin ,Genetics ,Molecular Biology ,Gene ,Plant Physiological Phenomena ,Southern blot ,biology ,Protoplasts ,DNA ,Plants ,biology.organism_classification ,genomic DNA ,Transformation (genetics) ,Blotting, Southern ,Meiosis ,chemistry ,Hygromycin B ,Plasmids - Abstract
We report the stable transformation of Physcomitrella patens to either G418 or hygromycin B resistance following polyethylene glycol-mediated direct DNA uptake by protoplasts. The method described in this paper was used successfully in independent experiments carried out in our two laboratories. Transformation was assessed by the following criteria: selection of antibiotic-resistant plants, mitotic and meiotic stability of phenotypes after removal of selective pressure and stable transmission of the character to the offspring; Southern hybridisation analysis of genomic DNA to show integration of the plasmid DNA; segregation of the resistance gene following crosses with antibiotic-sensitive strains; and finally Southern hybridisation analysis of both resistant and sensitive progeny. In addition to stable transformants, a heterogeneous class of unstable transformants was obtained.
- Published
- 1991
46. Developmental genetic studies of the moss, Physcomitrella patens
- Author
-
D J, Cove, W, Kammerer, C D, Knight, M J, Leech, C R, Martin, and T L, Wang
- Subjects
Cytokinins ,Gene Expression Regulation ,Genetic Techniques ,Indoleacetic Acids ,Light ,Mutation ,Plant Development ,Plants ,Genes, Plant ,Gravitation - Abstract
The development of the haploid gametophyte stage of Physcomitrella patens presents excellent opportunities for the detailed study of plant morphogenesis at the cellular level. The filamentous protonema undergoes a number of developmental transitions that can be observed directly in living material using time-lapse video microscopy and that can be manipulated both by treatment with phytohormones and by environmental stimuli. Mutants affecting these processes can be isolated and can be analysed using conventional as well as parasexual methods. Molecular biological techniques are now being established since these will be essential if the mechanisms that bring about morphogenetic processes are to be understood at the molecular level. A technique for genetic transformation has been devised and is being exploited to attempt to tag developmentally-relevant genes using maize transposons. Changes in gene activity associated with developmental transitions and in response to treatment with phytohormones and environmental stimuli are being studied using cDNA library subtraction techniques. Heterologous genes involved in the control of transcription and of the cell cycle are being used to probe the P. patens genome to identify possible homologues involved in developmental regulation.
- Published
- 1991
47. The relative effectiveness of 2-hydroxy-4-(methylthio) butanoic acid and DL-methionine in young swine
- Author
-
C. W. Wuelling, C. D. Knight, C. A. Atwell, Francis J. Ivey, and Julia J. Dibner
- Subjects
medicine.medical_specialty ,Swine ,Lysine ,Cystine ,Weaning ,Biology ,Zea mays ,chemistry.chemical_compound ,Methionine ,Animal science ,Leucine ,Internal medicine ,Genetics ,medicine ,Protein biosynthesis ,Animals ,Potency ,Cells, Cultured ,General Medicine ,Milk Proteins ,Animal Feed ,Whey Proteins ,medicine.anatomical_structure ,Endocrinology ,Liver ,chemistry ,Cell culture ,Protein Biosynthesis ,Hepatocyte ,Food, Fortified ,Animal Science and Zoology ,Food Science - Abstract
We compared the effectiveness of 2-hydroxy-4-(methylthio) butanoic acid (HMB) and DL-methionine (DLM) as sources of L-methionine activity in methionine-deficient primary cultures of pig liver cells and methionine-deficient early-weaned pigs. Viable hepatocytes were obtained from minced pig liver and maintained in a high density, differen- tiated, nonproliferation cell culture system. Culture medium was supplemented with HMB, DLM, or L- methionine, and cells were pulse-dosed with L- ( 14 C(U))leucine for 24 h to determine the level of protein synthesis. Leucine incorporation per milligram of protein indicated a six-to eightfold increase in protein synthesis ( P < .01) with methionine levels between 5 and 10 mM, regardless of source of methionine activity. Two 24-pen replicate methionine dose titrations were conducted with 95 early-weaned commercial crossbred pigs. The pelleted corn, dried whey, and porcine plasma basal diet contained 1.5% lysine, .23% methionine, and .48% cystine and was supplemented with 0, .05, or .10% methionine activity as DLM or HMB for 21 d. There was a 134, 104, and 61% increase ( P < .01) in cumulative ADG for each successive week on study with a 30 and 19% improvement in feed/gain ( P < .01) after 7 and 14 d. Performance responses due to source of methionine activity did not differ and slope ratio potency determi- nations (gain vs intake of methionine source) of HMB vs DLM indicated a 119, 111, and 95% relative activity for cumulative weekly performance. These results support the hypothesis that HMB and DLM provide equimolar levels of methionine activity in swine.
- Published
- 1998
- Full Text
- View/download PDF
48. The Effects of Intestinal Escherichia Coli 263, Intravenous Infusion of Escherichia Coli 263 Culture Filtrate and Iron Dextran Supplementation on Iron Metabolism in the Young Pig
- Author
-
D. M. Forsyth, K. C. Klasing, and C. D. Knight
- Subjects
Blood Glucose ,Dose ,Swine ,Iron ,Bacterial Toxins ,Biological Availability ,medicine.disease_cause ,Microbiology ,Andrology ,Escherichia coli ,Genetics ,medicine ,Animals ,Infusions, Parenteral ,Secretion ,Escherichia coli Infections ,Swine Diseases ,Chemistry ,General Medicine ,Mononuclear phagocyte system ,Metabolism ,Intestines ,Organ Specificity ,Shock (circulatory) ,Food, Fortified ,Circulatory system ,Iron-Dextran Complex ,Animal Science and Zoology ,medicine.symptom ,Food Science ,Blood sampling - Abstract
An experiment using 32 pigs in a 2(3) factorial arrangement of treatments was used to determine the effects on the (1) level of iron dextran supplementation, (2) iv infusion of an Escherichia coli 263 culture filtrate and (3) presence of E. coli 263 in a ligated intestinal segment, on the ability of the young pig to limit systemic Fe availability. Iron dextran was administered im 3 d postpartum. Culture filtrate was infused iv, E. coli were injected into ligated intestines and blood sampling was started at 14 d postpartum. Blood was taken every 2 h for 22 h, after which pigs were euthanized and livers, spleens and kidneys were removed. Pigs receiving 400 mg of iron dextran (HiFe) exhibited greater serum Fe (SFe) and lower total Fe-binding capacity (TIBC) than pigs injected with 100 mg Fe (LoFe). The effects of the E. coli culture filtrate infusion appeared to be associated with endotoxin-induced circulatory shock. The presence of E. coli in the intestine increased TIBC in LoFe pigs, but not in HiFe pigs. The increase in TIBC coincided with the time of maximal fluid secretion into the intestine. Intestinal E. coli also caused an increase in liver Fe content, particularly in HiFe pigs. These data suggest that intestinal E. coli can cause a shift of Fe from the plasma to the reticuloendothelial system, and pigs receiving high supplemental dosages of Fe are less able to limit the availability of Fe to microorganisms.
- Published
- 1984
- Full Text
- View/download PDF
49. The Viking Seismic Experiment
- Author
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T. C. D. Knight, W. F. Miller, Don L. Anderson, M. Fafi Toksöz, A. R. Lazarewicz, Gary V. Latham, George H. Sutton, Yosio Nakamura, Robert L. Kovach, and Frederick K. Duennebier
- Subjects
Seismometer ,Background noise ,Multidisciplinary ,Wind gust ,Mars Exploration Program ,Induced seismicity ,Geology ,Seismology ,Noise (radio) ,Remote sensing - Abstract
A three-axis short-period seismometer is now operating on Mars in the Utopia Planitia region. The noise background correlates well with wind gusts. Although no quakes have been detected in the first 60 days of observation, it is premature to draw any conclusions about the seismicity of Mars. The instrument is expected to return data for at least 2 years.
- Published
- 1976
- Full Text
- View/download PDF
50. Relationship of Delayed-Type Hypersensitivity and Acquired Cellular Resistance in Experimental Airborne Tuberculosis
- Author
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D.W. Smith, C. D. Knight Shapiro, and Gherry E. Harding
- Subjects
Male ,Tuberculosis ,Guinea Pigs ,Tuberculin ,Bacille Calmette Guerin ,Mycobacterium tuberculosis ,medicine ,Animals ,Immunology and Allergy ,Hypersensitivity, Delayed ,Tuberculosis, Pulmonary ,Analysis of Variance ,Immunity, Cellular ,biology ,Tuberculin Test ,Hypersensitivity skin testing ,business.industry ,biology.organism_classification ,medicine.disease ,Tuberculin Purified Protein Derivative ,Infectious Diseases ,Delayed hypersensitivity ,Immunology ,BCG Vaccine ,Female ,business ,Immunologic memory - Published
- 1974
- Full Text
- View/download PDF
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