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The large intestinal systems of fowl and swine recover nutrients from ileal indigesta by a strategically different manner. Indigesta with fowl enter a short colon where retro-peristalsis using urine from the urodeum carries small particulates and solutes into both ceca while coarse materials collect in the cloaca. Fowl repetitively add fine and soluble materials into both ceca to continue fermentation until complexity of the remainder exceeds microbial action, then contents apart from faeces are entirely evacuated. Indigesta with swine initially enter a short cecum followed by a lengthy progression through to the rectal ampulla. Wall out-pocketings of circular muscle or haustrae occur throughout the length of the pig's cecum and helicoidal colon. Each pocket carries contents acquired earlier in the cecum. Motility collects fines and solutes into haustrae during their progression through the colon whereas coarse particulates assemble in the core. Haustrae contents continually ferment during movement to the distal colon with resulting volatile fatty acids (VFA) and electrolytes being absorbed. Mucin loosely covers the lumen surface in caeca as well as helicoidal colon that may capture microbes from active intestinal contents as well as release others to sustain fermentation. The microbial community continually modifies to accommodate fibre complexity as encountered. Resistant starches (RS) and simple oligosaccharides rapidly ferment to yield VFA while encouraging butyric acid in the cecum and anterior colon, whereas non-starch polysaccharides (NSP) complexity requires extended durations through the remaining colon that enhance acetic acid. Residual fibre eventually results in undue complexity for fermentation and consolidates at termination of the colon. These compact pellets are placed on core contents to form faeces having a nodular surface. Acetic, propionic, and butyric acids represent the bulk of VFA and are derived from non-digestible carbohydrates. Fibrolytic enzymes, when supplemented to feed, may increase the proportion of oligosaccharides and simpler NSP to further the rate as well as extent of fermentation. Active absorption of VFA by mucosal enterocytes employs its ionized form together with Na+, whereas direct membrane passage occurs when non-dissociated. Most absorbed VFA favour use by the host with a portion of butyric acid together with by-products from protein digestion being retained to reform mucin and sustain mucosal integrity.

Fat added to poultry and swine feeds often contains abundant free fatty acids (FFA) that can impair digestible energy (DE). Placement of the fatty acid (FA) hydrocarbon chain in the helix core reformed from amylose creates a complex of both nutrients. Resulting modifications create a new structure termed the V-helix that becomes resistant to α-amylase. Granules in grain naturally contain minimal amounts of these complexes with more being generated during food manufacturing when moisture and heat release amylose in the presence of FFA. A paucity of FFA usually exists in complete feeds without sources of poor-quality fat. Animal fats and by-product meals from rendering are prominent in their saturated FFA content which favorably complex within the helix. V-helix-FA complexes may arise during their concurrent encounter of FFA together with amylose during feed manufacture, particularly pelleting. FFA in the gastrointestinal tract (GIT) are speculated to further form complexes when present together with amylose. Although amylose may be dissolved in the gastric and small intestinal milieu, FFA separately coalesce into hydrophobic fat droplets along with other dietary lipids. Formation of complexes is likely restricted until FFA are released into the aqueous phase during fat digestion. Although α-amylase may be prominent, V-helix-FA complexes being resistant to enzymic attack pass into the large intestine. Subsequent microbial catabolism of V-helices may generate volatile fatty acids that are absorbed by the mucosa; however, an inability to use FFA once released leads to their excretion and basis for decreased DE. Immature microbial populations with young animals usually lack the capacity to fully catabolize the V-helix, further extending the loss in DE.

An experiment was conducted to evaluate the effects of two commercial phytases on performance and bone mineralization of male broilers from two commercial strains when included into a diet marginal in both calcium (Ca) and non-phytate phosphorus (npP). Male chicks from two broiler strains (Strains 1 and 2; 320 of each) were placed on fresh bedding across 64 pens (10 birds/pen with 8 replicates/treatment). All birds were fed a corn-soybean meal diet (22% CP, 3,086kcal/kg) adequate in all nutrients except Ca and npP. Dietary treatments were arranged as a 2×4 factorial using 2npP/Ca combinations and four dietary treatments: 1) standard (0.45% npP, 1.0% Ca), 2) marginal (0.35% npP, 0.87% Ca), 3) marginal+500 FTU Phytase A, and 4) marginal+500FTU Phytase B. All diets were pelleted at 79°C, crumbled and provided from 0 to 21 days of age. Individual body weights and feed consumption were recorded at 21d of age and 24 birds per treatment were sacrificed for tibia breaking strength.Chicks of Strain 2 were 1.7g heavier (P0.05) in body weight at 21d of age. Body weight, body weight gain, feed consumption and bone strength were significantly decreased (P

The small intestinal mucosa acts to recover nutrients from the lumen while providing a barrier against potential hazards. Its unstirred water layer (USWL) at the lumen interface involves membrane associated mucin linearly protruding from underlying microvilli that entangles secretory mucin released from local goblet cells. Both mucin sources are dominated by repetitive O-glycosylated areas dependant on threonine, serine, glycine, and proline. Secretory mucin differs from membrane attached mucin by further employing multiple cystines that interconnect these areas into a net-like molecular sieve. All of the glycosylated areas have ionizable acidic groups credited with reducing pH from that in the lumen to create a micro environment favoring enzymes finalizing digestion while optimizing nutrient terms for absorption. Erosion of the USWL and/or abuse of the membrane due to lumen threats require continuous repair. The aforementioned amino acids are necessary in substantial amounts while vitamin B6 collaborates with vitamin A as meaningful cofactors for mucin synthesis. Marginal inadequacies of these nutrients during inordinate demand are expected to impair mucin replacement. In turn, marginal increases in feed conversion likely occur while fostering the probability of necrotic enteritis together with gizzard erosions. Abuse of the absorptive membrane is of particular concern from fatty acid hydroperoxides because of their continual presence in feed and inability of the USWL to provide protection. These hydroperoxides threaten membrane integrity by their inclusion in micelles during digestive events with fat thereby permitting transit through the USWL. Once coalesced with membrane phospholipids, structural aberrations are visualized as interfering with nutrient recovery while enabling leakage of cell contents to potentiate wet excreta. Inclusion of dietary vitamin E along with vitamin A into micelles with fatty acid hydroperoxides provides relief by quenching further peroxidation. Assuring cystine, threonine, glycine, and serine that are directly available as such together with vitamins A, E, and B6 represents one approach toward optimizing maintenance of the intestinal mucosa. [ABSTRACT FROM AUTHOR]

White striping (WS) is an alteration of breast and thigh muscles of broiler chickens characterized by the presence of white striations parallel to the direction of muscle fibers. This study was performed to evaluate the prevalence and the predisposing factors to WS in commercial broilers of different weight reared in northern Italy. Fifty seven broiler flocks, including animals of medium- and heavy-weight, were grossly evaluated at slaughter for the presence of WS. For each flock, breeding data (mean BW at slaughter, ADG, sex, color of skin and fat, genetic line, age, antibiotic treatment, and prevalence of deep pectoral myopathy) were collected and statistically analyzed to assess their correlation with WS. Histology of breast fillets affected by different grades of WS was performed to evaluate potential differences between medium- and heavy-weight broilers. The overall prevalence of WS in medium- and heavy-weight broilers (mean BW 2.59 ± 0.13 kg and 3.64 ± 0.34 kg, respectively) was 70.2 ± 7.9% and 82.51 ± 8.5%, respectively, while the percentage of severe WS was 13.3 ± 7.1% and 25.7 ± 12.8%, respectively. A strong correlation was found between presence of WS, BW at slaughter, and ADG (Pearson correlation = 0.69, P < 0.01; Pearson correlation = 0.67, P < 0.01). WS also closely correlated with the prevalence of deep pectoral myopathy (Spearman's Rho slaughterhouse 1 = 0.74, Spearman's Rho slaughterhouse 2 = 0.51, P < 0.01). No correlation was found between genetics or sanitary status of the flock and WS. Histology confirmed that breasts with WS lesions were affected by a polyphasic degenerative and necrotizing myopathy, and that the lesions, as expected, were more severe in heavy-weight broilers. In conclusion, WS is a major concern in commercial meat poultry reared in Italy, affecting more severely heavier broilers, and it is mainly related to the BW and ADG of animals. [ABSTRACT FROM AUTHOR]

Clostridium perfringens A (CPA) entering the gastrointestinal system depends on favorable conditions to develop and subsequently extend pathogenicity. Reduction in digestive dynamics progressing from the duodenum decreases lumen oxygen, leading to anaerobic conditions in the distal lumen that favor CPA. When nutritional support is concurrently provided, an expanding population threatens the mucosa. Dietary nonstarch polysaccharides that increase viscosity further impair oxygen transfer from the mucosa, improving the ability of CPA to thrive. Incompletion of feed digestion early in the small intestine along with endogenous N provide additional support for population expansion. Glucosidase versatility with mucin elicited by distal CPA concurrently erodes the villus unstirred water layer at the apex, providing access to underlying binding sites for colonization. Proteolytic destruction within the lamina propria supports colonization to create subclinical necrotic enteritis. Eventual vascular entry of CPA and toxins provides a portal path for instituting cholangiohepatitis. Liver condemnations from inspection detect acute flock infection compared with preceding marginal losses in nutrient absorption that decrease feed efficiency. Enterocyte lysis by coccidia enable CPA access to binding sites, thereby extending villus necrosis and further impairing feed conversion. Loss of BW and increased mortality follow as mucosa involvement proceeds. In practice, supplemental feed hemicellulases that reduce digesta viscosity minimize a favorable environment for CPA, while superimposing a combination of amylase, phytase, and protease avoids nutritional support. Physical dynamics of the small intestine together with characteristics of feed that modify digesta viscosity and nutritional availability are central to establishing transient CPA as a pathogen. [ABSTRACT FROM AUTHOR]

During sporulation in Bacillus subtilis, the onset of activity of the late forespore-specific sigma factor σG coincides with completion of forespore engulfment by the mother cell. At this stage, the forespore becomes a free protoplast, surrounded by the mother cell cytoplasm and separated from it by two membranes that derive from the asymmetric division septum. Continued gene expression in the forespore, isolated from the surrounding medium, relies on the SpoIIIA-SpoIIQ secretion system assembled from proteins synthesised both in the mother cell and in the forespore. The membrane protein insertase SpoIIIJ, of the YidC/Oxa1/Alb3 family, is involved in the assembly of the SpoIIIA-SpoIIQ complex. Here we show that SpoIIIJ exists as a mixture of monomers and dimers stabilised by a disulphide bond. We show that residue Cys134 within transmembrane segment 2 (TM2) of SpoIIIJ is important to stabilise the protein in the dimeric form. Labelling of Cys134 with a Cys-reactive reagent could only be achieved under stringent conditions, suggesting a tight association at least in part through TM2, between monomers in the membrane. Substitution of Cys134 by an Ala results in accumulation of the monomer, and reduces SpoIIIJ function in vivo. Therefore, SpoIIIJ activity in vivo appears to require dimer formation. [ABSTRACT FROM AUTHOR]

Two highly similar RNA polymerase sigma subunits, σF and σG, govern the early and late phases of forespore-specific gene expression during spore differentiation in Bacillus subtilis. σF drives synthesis of σG but the latter only becomes active once engulfment of the forespore by the mother cell is completed, its levels rising quickly due to a positive feedback loop. The mechanisms that prevent premature or ectopic activation of σG while discriminating between σF and σG in the forespore are not fully comprehended. Here, we report that the substitution of an asparagine by a glutamic acid at position 45 of σG (N45E) strongly reduced binding by a previously characterized anti-sigma factor, CsfB (also known as Gin), in vitro, and increased the activity of σG in vivo. The N45E mutation caused the appearance of a sub-population of pre-divisional cells with strong activity of σG. CsfB is normally produced in the forespore, under σF control, but sigGN45E mutant cells also expressed csfB and did so in a σG-dependent manner, autonomously from σF. Thus, a negative feedback loop involving CsfB counteracts the positive feedback loop resulting from ectopic σG activity. N45 is invariant in the homologous position of σG orthologues, whereas its functional equivalent in σF proteins, E39, is highly conserved. While CsfB does not bind to wildtype σF, a E39N substitution in σF resulted in efficient binding of CsfB to σF. Moreover, under certain conditions, the E39N alteration strongly restrains the activity of sF in vivo, in a csfB-dependent manner, and the efficiency of sporulation. Therefore, a single amino residue, N45/E39, is sufficient for the ability of CsfB to discriminate between the two foresporespecific sigma factors in B. subtilis. [ABSTRACT FROM AUTHOR]

A large number of proteins are known to reside at specific subcellular locations in bacterial cells. However, the molecular mechanisms by which many of these proteins are anchored at these locations remains unclear. During endospore formation in Bacillus subtilis, several integral membrane proteins are located specifically at the interface of the two adjacent cells of the developing sporangium, the mother cell and forespore. The mother cell membrane protein SpoIIIAH recognizes the cell-cell interface through an interaction with the forespore membrane protein SpolIQ, and then the other proteins are positioned there by the SpoIIIAH-SpoIIQ complex. In this study, we investigated the molecular mechanisms underlying the formation of the SpoIIIAH-SpoIIQ complex. Using gel filtration chromatography and isothermal titration calorimetry, we measured the binding parameters that characterize the SpoIIIAH-SpoIIQ interaction in vitro. We also demonstrated that the interaction of SpoIIIAH and SpoIIQ is governed by their YscJ and degenerate LytM domains, respectively. Therefore, the LytM domain of SpoIIQ provides the positional cue that dictates the localization of mother cell membrane proteins to the mother cell-forespore interface. [ABSTRACT FROM AUTHOR]

Sporulation in Bacillus subtilis involves two cells that follow separate but coordinately regulated developmental programs. Late in sporulation, the developing spore (the forespore) resides within a mother cell. The regulation of the forespore transcription factor σG that acts at this stage has remained enigmatic. σG activity requires eight mother-cell proteins encoded in the spoIIIA operon and the forespore protein SpoIIQ. Several of the SpoIIIA proteins share similarity with components of specialized secretion systems. One of them resembles a secretion ATPase and we demonstrate that the ATPase motifs are required for σG activity. We further show that the SpoIIIA proteins and SpoIIQ reside in a multimeric complex that spans the two membranes surrounding the forespore. Finally, we have discovered that these proteins are all required to maintain forespore integrity. In their absence, the forespore develops large invaginations and collapses. Importantly, maintenance of forespore integrity does not require σG. These results support a model in which the SpoIIIASpoIIQ proteins form a novel secretion apparatus that allows the mother cell to nurture the forespore, thereby maintaining forespore physiology and σG activity during spore maturation. [ABSTRACT FROM AUTHOR]

Experimentation examined if Gly and Ser (Gly + Ser) and Pro from gelatin inclusion in low and high CP feeds would relieve impaired performance of broilers after vaccination for coccidiosis. Broilers in floor pens were fed 20-18-16% or 23-20-18% CP cornsoybean meal regimens from 0 to 8 wk of age such that 1 or more of the most limiting essential amino acid levels were similar across treatments and considered adequate respectiye of age. Gelatin was included in diets at 2%, which contributed Gly + Ser and Pro levels comparable to using 5% meat meal. Half of the chicks were spray-vaccinated with live oocysts before placement and received nonmedicated feed, whereas the other half received coccidiostat-medicated (salinomycin) feed to 6 wk of age. Vaccination adversely affected live performance in the first 3 wk, which could not be fully compensated to the level of birds receiving coccidiostat by the end of experimentation. Inclusion of gelatin mitigated vaccination response through the first 3 wk, while improving overall live performance of birds fed low CP diets. Gelatin had no effect on carcass composition, but the low CP regimen increased abdominal fat and reduced carcass and breast meat relative to high CP feeds. Vaccination also reduced overall carcass weight; however, part yields were not affected. Males were generally more sensitive to treatments than females. The conditionally essential amino acids Gly + Ser and Pro may be important factors in recovery from live anticoccidial vaccines. [ABSTRACT FROM AUTHOR]

At an early stage during Bacillus subtilis endospore development the bacterium divides asymmetrically to produce two daughter cells. The smaller cell (forespore) differentiates into the endospore, while the larger cell (mother cell) becomes a terminally differentiated cell that nurtures the developing forespore. During development the mother cell engulfs the forespore to produce a protoplast, surrounded by two bilayer membranes, which separate it from the cytoplasm of the mother cell. The activation of σ[supG], which drives late gene expression in the forespore. follows forespore engulfment and requires expression of the spolllA locus in the mother cell. One of the spolllA-encoded proteins SpolllAH is targeted specifically to the membrane surrounding the forespore, through an interaction of its C-terminal extracellular domain with the C-terminal extracellular domain of the forespore membrane protein SpollQ. We identified a homologous relationship between the C-terminal domain of SpolllAH and the YscJ/FliF protein family, members of which form multimeric rings involved in type Ill secretion systems and flagella. If Sp0IIIAH forms a similar ring structure, it may also form a channel between the mother cell and forespore membranes. To test this hypothesis we developed a compartmentalized biotinylation assay, which we used to show that the C-terminal extracellular domain of Sp0IIIAH is accessible to enzymatic modification from the forespore cytoplasm. These and other results lead us to suggest that Sp0IIIAH forms part of a channel between the forespore and mother cell that is required for the activation of σ[supG]. [ABSTRACT FROM AUTHOR]

Objective: To estimate the long-term effects of cancer survivorship on the employment of older workers.Data Sources: Primary data for 504 subjects who were 55-65 in 2002 and were working when diagnosed with cancer in 1997-1999, and secondary data for a comparison group of 3,903 similarly aged workers in the Health and Retirement Study (HRS) in 2002.Study Design: Three employment outcomes (working, working full time, usual hours per week) were compared between the two groups. Both Probit/Tobit regressions and propensity score matching were used to adjust for potentially confounding differences between groups. Sociodemographic characteristics, baseline employment characteristics, and the presence of other health conditions were included as covariates.Data Collection Methods: Four telephone interviews were conducted annually with cancer survivors identified from tumor registries at four large hospitals in Pennsylvania and Maryland. Many of the questions were taken from the HRS to facilitate comparisons.Principal Findings: Cancer survivors of both genders worked an average of 3-5 hours less per week than HRS controls. For females, we found significant effects of survivorship on the probability of working, the probability of working full-time, and hours. For males, survivorship affected the probability of full-time employment and hours without significantly reducing the probability of working. For both genders, these effects were primarily attributable to new cancers. There were no significant effects on the employment of cancer-free survivors.Conclusions: Survivors with recurrences or second primary tumors may particularly benefit from employment support services and workplace accommodation. Reassuringly, any long-term effects on the employment of cancer-free survivors are fairly small. [ABSTRACT FROM AUTHOR]

The current research was designed to determine the effect of phytase and glucanase on the energy value of corn and soybean meal (SBM) separately for broilers at various ages. The treatments were arranged as a 2 × 2 × 2 factorial, with 0 or 500 phytase units/kg or with 0 or 500 units of glucanase/kg, supplemented to either corn or SBM, with each combination represented by 6 cages of 10 birds. Diets of pure corn and soybean meal were not supplemented with additional nutrients, and were fed for 3-d periods beginning at 7, 14, or 21 d of age, representing the immature, transitional, and mature digestive tract, respectively. Each experiment was per- formed on a different group of birds from the same hatch. At the end of each experimental period, the broilers were euthanized and the contents of the ileum, duodenum and jejunum (pooled), and pancreas were removed for analysis. The ileal samples were analyzed for acid-insoluble ash and gross energy to determine the ileal-digestible energy (IDE) of the feedstuffs. The pancreas and duodenal-jejunal samples were analyzed for proteolytic and amylase activity to determine the influence of practical levels of phytate on enzyme activity. Results showed that neither phytase nor glucanase influenced enzyme activity in the digesta or pancreas, suggesting that practical levels of phytate did not influence the activity of proteolytic enzymes or amylase. Phytase did not influence the IDE value of either corn or SBM, and improved DM digestibility of the feed only for corn fed at 21 to 23 d. Glucanase improved IDE in both the corn and SBM diets at all ages, and improved DM digestibility in corn diets at all ages and SBM diets fed at 14 to 16 d. The IDE and DM digestibility of corn and the digesta and pancreatic enzyme activities increased with age, whereas the IDE of SBM was similar among age groups. The relative effect of glucanase on IDE of both feedstuffs was similar among age groups. [ABSTRACT FROM AUTHOR]

Nutrient needs central to satisfactory egg incubation well-being undergo several major changes from fertilization until the reliance of the chick on feed. Glucose is central, with the initiation of incubation until the chorioallantois accesses O2 to use for fatty acid oxidation. Nutrient recovery from albumen and yolk is largely commensurate with body assembly through to completion of the embryo by 14 d. Remaining albumen mixes with the amniotic fluid and is orally consumed until initiation of emergence. A portion of the albumen is absorbed by the small intestine to expand body glycogen reserves. The residual not absorbed contains digestive enzyme contributions and enters the yolk sac through its stalk at the jejunum and ileum. Interaction of the albumen-amnion digestive enzyme mixture with yolk sac contents leads to diverse alterations that influence subsequent use of lipids. Rapid removal of very low-density lipoprotein en- sues, until pipping with triglycerides, expanding body fat depots while cholesterol deposits in the liver. A concurrent translocation of Ca from shell mineralizes the skeletal system while also crossing yolk sac villi for deposition on phosvitin-based granules accruing in its lumen. Loss of chorioallantois with pipping and the start of pulmonary respiration predispose a dependence on glycolysis to support emergence. Small intestinal villi progressively reorient their enterocytes from macromolecule transfer to competence at digestion and absorption after hatching. Mobilization of body fat complements contributions from the yolk sac to provide fatty acids for generating energy, heat, and water while also combining with hepatic cholesterol for membrane expansion and continued development. Calcified granules evacuate the yolk sac to further skeletal mineralization in the absence of shell contributions. Egg mass, its interior quality, and turning during early incubation directly influence the ability of the embryo to access nutrients and provide resources to support emergence and the transition of the chick to self-sufficiency. [ABSTRACT FROM AUTHOR]

Tryptophan requirements of broiler males from 42 to 56 d of age were studied. Ross × Ross 308 chicks were placed in an open-sided house, and provided common starter and grower diets from 0 to 42 d of age. Subsequently, a corn, soybean meal, corn gluten meal, and gelatin combination of feedstuffs provided 0.12% Trp to which 0.04% increments of L-Trp were supplemented at the expense of an isonitrogenous amount of L-Glu to 0.24%. Birds that received diets containing 0.12% Trp exhibited aberrant behavior based on the spillage of considerable amounts of feed from the trough and contamination of adjacent waterers with floor litter. There were reductions in body weight gain, feed conversion, and carcass and breast fillets weights and yields with dietary Trp at 0.12%, but these were not affected at Trp levels at or above 0.16%. Exponential regression analyses showed that body weight gain improved as Trp increased, with maximum overall performance being attained at 0.17%, whereas chilled carcass weight maximized at 0.16% dietary Trp. Nitrogen retention measured using the same experimental feeds and sample birds at 48 to 49 d of age was unaffected by dietary Trp. Plasma uric acid, albumin, total protein, and aspartate-transferase measured concurrently with nitrogen retention were not altered; however, blood glucose was reduced in broilers fed 0.12% dietary Trp. Overall results suggest that broiler males need approximately 0.17% dietary Trp between 42 and 56 d of age, which closely agrees with the NRC (1994) recommendation of 0.16% Trp estimated from modeling for this feeding period. [ABSTRACT FROM AUTHOR]

Five hundred broiler males were grown to 56 d and processed under common terms. Front halves were deboned 24 h postmortem to obtain breast fillets, and CIELAB light reflectance was measured on the skin side of each fillet 24 h later. All fillets were bagged and frozen (-20° C) for 5 ma Then the fillets exhibiting the lowest (dark), median (normal), and highest (pale) L* values 48 h postmortem were thawed (3 d at 4°C) and cooked (internal temperature 80°C). Thawing reduced the L* value in the pale fillets and increased it in the dark ones, and cooking further increased L* value and reduced the differences in L*, a*, and b* between groups. Thawing and cooking losses were not affected by initial L* value until they were combined. Total losses increased with initial L*, which was in parallel with a lower increase in thickness after cooking. [ABSTRACT FROM AUTHOR]

Eight hundred broiler males were grown to 56 d and processed under common terms while maintaining individual identity. Front halves were deboned 24 h postmortem (PM) to obtain breast fillets, and CIELAB light reflectance was immediately measured on the skin side of each fillet. Fillets were bagged and held at 4°C for 24 h, and then 20 fillets exhibiting the darkest (47.3 to 57.5), lightest (71.1 to 76.4), and median (63.7 to 64.0) L&ast; values were selected and trimmed to best define the pectoralis major. Remeasurement of light reflectance at 48 h PM revealed decreased L&ast; values solely associated with fillets having the highest L&ast; at 24 h. One-half of the fillets representing each category was frozen (4 d at -20°C) and thawed (3 d at 4°C). The L&ast; value, after thawing, decreased from the 48 h PM value, which equivalently occurred in for all L&ast; categories. Although 48 h PM fillets from each L&ast; category were of similar weights, their lengths and widths increased with L&ast; value. Exudate lost with thawing increased with L&ast; value and paralleled decreases in length and width to equalize dimensions among sources. [ABSTRACT FROM AUTHOR]

An experiment was conducted using Ross × Ross 308 males to estimate the proportion of dietary valine needed to optimize performance in broilers from 42 to 56 d of age. All birds received common feeds from 0 to 42 d, and then experimental diets were given to 56 d of age. A diet consisting of corn, soybean meal, and corn gluten meal (17% CP, 3.25 kcal of ME/g) having 0.60% valine served as basal feed. All other essential amino acids were above recommended levels. Successive additions of 0.07% of L-valine were isonitrogenously substituted for L-glutamic acid up to a total of 0.81%. Regression analysis (95% of response) indicated that valine at 0.72% of the diet maximized body weight gain, whereas 0.73% optimized feed conversion. Depot fat removed from the abdominal cavity after processing was unaltered, and weights of resultant chilled carcasses maximized at 0.73% valine in parallel with final live weight. The amount of fillets recovered from chilled carcasses optimized at 0.73% valine; however, the incidence of distinctive blood streaks in the meat (splash) progressively increased with valine as did the level of redness apart from streaking, based on light reflectance. Given lysine at 0.85%, a ratio of 0.86 with valine appears to be adequate. The presently determined requirement of 0.73% total valine (0.67% digestible) for broiler males from 42 to 56 d of age is slightly higher than the 0.70% recommended by the NRC. [ABSTRACT FROM AUTHOR]

Determines the methionine and cystine requirements of slow- and fast-feathering broiler males from three to six weeks old. Whole carcass yield of slow- and fast-feathering broiler males at six week of age after receiving feeds; Effect of increasing dietary cystine on live performance of slow-feathering birds; Composition of the common feed and sulfur amino acid-deficient basal diet.

Determines the methionine and cystine requirements of slow- and fast-feathering male broilers from zero to three weeks old. Effect of differences in feathering rate on broiler's need for cysteine; Composition of sulfur amino acid-deficient corn-soybean meal basal diet; Nitrogen balance of slow- and fast-feathering male broilers.

Examines arginine need of male broilers between the ages of 42 to 56 days, in conjunction with dietary protein approaching a previously advocated ideal amino acid pattern. Suggestion that additional amounts of arginine would be needed for immunological and connective tissue challenges.

Investigates the region of GerE required for promoter activation in bacillus subtilis. Description of GerE; Effects of single alanine substitutions on transcription; Classification of the transcriptional activators in bacteria.

Examines the effects of single base pair substitutions in the high affinity GerE protein binding site on the sigK promoter in Bacillus subtilis. Production of a protein that binds with equal affinity to two sites that differ by one base pair; Identification of the nucleotide sequence that signals recognition and binding by GerE; Mutagenesis of the DNA binding region of GerE.

Presents a speech by the mayor of Alexandria, Virginia, discussing the problems posed by the growth of open-air drug market in the city's housing projects. Lessons from the death of Corporal Charles Hill in a crack house that the housing authority was powerless to shut down; Flaws in the country's policy on the presence of a known crack house in public housing; Call for exercise of common sense and judicial responsibility.

Cites a study which examined the effects of single alanine substitutions, in an attempt to determine SpoOA activities in the bacterium Bacillus subtilis. What SpoOA is; Isolation of the derivatives of sigH mutants of SpoOA; Results of the study.

Tests whether base pair substitutions in the -10 region of a sigmaB-dependent promoter could signal its utilization by sigmaE-RNA polymerase in bacteria. Changes in specificity upon amino acid substitutions in sigmaE; Mutagenesis and expression of sigE.

Describes the cloning and characterization of spoVR, a gene from Bacillus subtilis involved in spore cortex formation. Increase in the proportion of phase-dark spores; Decrease in the accumulation of dipicolinate; Initiation of the expression of spoVR.

Endospore formation in Bacillus subtilis is a morphologically complex process in which the bacterium divides into two compartments (forespore and mother cell) that follow different developmental paths. Compartment-specific transcription in the forespore is initiated by RNA polymerase containing σF, and results in the forespore-speciflc production of σG, which directs most of the subsequent forespore-speciflc transcription. The activity of σF is thought to be restricted to the forespore by the sigma factor antagonist SpollAB. We used antibodies against SpollAB to monitor its accumulation during sporulation. We found that SpollAB accumulates early after the initiation of sporulation, and that it was present in the mother-cell compartment 2h after σF became active in the forespore. SpollAB disappeared preferentially from the forespore during development, and its disappearance from the forespore compartment correlated with the activation of σG in that compartment, raising the possibility that SpollAB may be involved regulating σG activity. We tested whether SpollAB could antagonize σG activity by replacing the σH-dependent promoter that drives expression of spolllG, the structural gene for σG, with a σH-dependent promoter. This resulted in a lytic phenotype that was supressed by the simultaneous expression of a plasmid-borne copy of spollAB. This suggests that SpollAB can suppress this effect of σG Moreover, these cells formed spores efficiently. Since σG the forespore by the σF-dependent transcription of its structural gene that normally occurs in wild-type cells, the forespore-specific activity of σG required for Sporulation appears to have resulted from expression of SpollAB. [ABSTRACT FROM AUTHOR]

The transcriptional regulator Spo0A activates transcription from two types of promoters. One type of promoter is used by RNA polymerase containing σA, whereas the other type is used by RNA polymerase containing σH. There are Spo0A-binding sites near the -35 region of both types of promoters. It has been reported that some transcriptional regulators that bind near the -35 regions of promoters directly interact with the sigma subunit of RNA polymerase. Therefore, we looked for evidence that Spo0A interacts with both sigma factors by searching for single amino acid substitutions in these factors that specifically prevent expression from Spo0A-dependent promoters, but that do not decrease activity of Spo0A-independent promoters. Two such amino acid substitutions were isolated in σA and one was isolated in σH. The amino acid substitutions in σA prevented expression from the Spo0A-activated promoters, spollG and spollE, but expression was not impaired from the Spo0A-independent, σA-dependent promoter tms or from the Spo0A-activated, σH-dependent promoter, spollA. The amino acid substitution in σH prevented expression from the spollA promoter but not from the Spo0A-independent promoter, citGp2, which is used by σH-RNA polymerase. All of these amino acid substitutions occur in the carboxyl terminus of the sigma factors. These amino acid substitutions may define the sites of contact between the sigma factors and Spo0A. The ability of response regulators such as Spo0A to interact with multiple sigma factors may increase the variety of responses made by bacteria using a limited number of transcription factors. [ABSTRACT FROM AUTHOR]

The allergy preventive effect of extensively (N) and partially (PH) hydrolysed cows' milk formulas compared with a regular formula (RM) was assessed in 155 infants with a family history of allergy. No cows' milk was given during the first nine months of life and no egg and fish up to 12 months of age. Breast feeding mothers avoided the same foods. At weaning the infants were randomised to one of the formula groups. The cumulative incidence of atopic symptoms at 18 months was 51, 64, and 84% in the N, PH, and RM groups, respectively. From 6 to 18 months there were significantly less cumulative atopic symptoms in the N group compared with the RM group, and significantly less than the PH group up to 6 (N = 25%; PH = 46%) and 9 months (N = 34%, PH = 58%). At 9 months significantly fewer infants in the N group (10%) than in the PH group (33%) had a positive skin prick test to eggs. The findings support an allergy preventive effect of an extensively hydrolysed formula, but not of a partially hydrolysed formula, during the first 18 months of life of high risk infants. [ABSTRACT FROM AUTHOR]