162 results on '"Spencer JL"'
Search Results
2. Ecological considerations in the sustainable development of terrestrial biofuel crops
- Author
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Raghu, S, Spencer, JL, Davis, AS, and Wiedenmann, RN
- Published
- 2011
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3. Correlations of genetic resistance of chickens to Marek's disease viruses with vaccination protection and in vivo response to phytohemaglutinin
- Author
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Gavora, JS, Spencer, JL, Okada, I, Grunder, AA, Griffin, PS, and Sally, E.
- Published
- 1990
- Full Text
- View/download PDF
4. Breeding for immune responsiveness and disease resistance1
- Author
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Spencer Jl and Gavora Js
- Subjects
Vaccination ,Natural selection ,Immune system ,Resistance (ecology) ,business.industry ,General Medicine ,Disease ,Plant disease resistance ,Heritability ,Biology ,business ,Selection (genetic algorithm) ,Biotechnology - Abstract
Summary Animal production efficiency, and product volume and quality can be greatly increased by reducing disease losses. Genetic variation, a prerequisite for successful selection, has been found in animals and poultry exposed to a variety of viral, bacterial and parasitic infections. Breeding for disease resistance can play a significant role alone or in combination with other control measures including disease eradication, vaccination and medication. Feasibility of simultaneously improving resistance to specific diseases and production traits has been demonstrated. However, selection for specific resistance to all diseases of animals and poultry is impossible. Development of general disease resistance through indirect selection primarily on immune response traits may be the best long-term strategy but its applicability is presently limited by insufficient understanding of resistance mechanisms. Another hindrance may be negative genetic correlations among various immune response functions: phagocytosis, cell mediated and humoral immunity. To better assess the feasibility of increasing general disease resistance by indirect selection we must obtain estimates of heritability for immune response, disease resistance, and economic production traits, as well as genetic correlations among these traits. The present level of disease resistance in farm animals resulted from natural selection and from correlated responses to selection for production traits while the influence of artificial selection for resistance was minimal. Future research should be directed towards developing and applying breeding techniques that will increase resistance to diseases without compromising production efficiency and product quailty. This will require cooperation of immunogeneticists, veterinarians and animal and poultry breeders. Significant progress in the improvement of resistance to diseases may result from the application of new techniques of molecular genetics and cell manipulation.
- Published
- 2009
5. Carbohydrate intolerance and kidney stones in children in the Goldfields
- Author
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Baldwin, DN, primary, Spencer, JL, additional, and Jeffries-Stokes, CA, additional
- Published
- 2003
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6. Progress towards eradication of lymphoid leukosis viruses ‐ A review
- Author
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Spencer Jl
- Subjects
General Immunology and Microbiology ,Food Animals ,Virus transmission ,Immunology ,Animal Science and Zoology ,Congenital transmission ,Flock ,Biology ,Virology ,Virus ,Horizontal transmission - Abstract
More than 20 years have now elapsed since technology was developed for producing chickens free of infection with exogenous lymphoid leukosis virus (LLV). However, it is only in recent years that commercial poultry breeders have initiated programmes to reduce the prevalence of infection in their stocks. This review considers advances that make large scale eradication feasible, even though methods for detecting infection and thus breaking the cycle of virus transmission are not completely effective. Congenital transmission of LLV occurs before eggs are incubated. Although chickens infected in this manner shed virus throughout their lives in faeces, saliva and remnants of cornified cells from skin, horizontal spread is slow. Nevertheless, horizontal transmission is important since it frequently results in persistent low level infections that are difficult to detect. Since horizontally infected dams are often erratic in congenitally transmitting virus, the prevalence of hens in a flock that have the potential for congenital transmission may be markedly higher than the actual rate of such transmission. Naturally infected chickens may have generalised infections, but even in these there are localised sites within certain organs that are prone to production of complete virus particles. While LLVs are usually considered avirulent at the cellular level, myocardial cells from some adult chickens may contain intracytoplasmic viral matrix inclusion bodies that are accompanied by swelling of these cells. Myocardial lesions may be one of many factors that contribute to reduced egg and meat production associated with subclinical LLV infections. While the enzyme-linked immunosorbent assay for group specific viral antigen in egg albumen appears to be the most efficient method for detecting dams that congenitally transmit virus, no combination of test procedures has proven 100% effective in identifying infected chickens. Rearing newly-hatched chickens in small isolated groups for 6 to 8 weeks would allow infection to spread among those in direct contact and this should facilitate identification of infected groups. Management practices applied by the poultry industry to maintain flocks free of mycoplasmas and other pathogens should be adequate for the control of LLV.
- Published
- 1984
7. Theory, Characteristics, and Operating Parameters of Portable Optical Emission Spectrometers for the On-Site Sorting and Identification of Steels
- Author
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Spencer, JL
- Abstract
Portable optical emission spectrometers are evolving as important tools for the on-site sorting and identification of metals. Their analytical precision and accuracy, while not quite as good as laboratory systems, are more than adequate for sorting mixes and most grade verification requirements. The intentions of this paper are to provide a brief review of the technology and history of emission spectrometers, and then to describe parameters, operation, capabilities and limitations of the device for plain carbon, low alloy, and stainless steels.
- Published
- 1987
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8. Theory, Characteristics, and Operating Parameters of Portable Optical Emission Spectrometers for the On-Site Sorting and Identification of Steels
- Author
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Wolfenden, A, primary and Spencer, JL, additional
- Published
- 1987
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9. Marek's Disease Herpesvirus: In Vivo and in vitro Infection of Kidney Cells of Different Genetic Strains of Chickens
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Spencer Jl
- Subjects
Infectivity ,Kidney ,General Immunology and Microbiology ,viruses ,Biology ,Quantitative correlation ,Virology ,In vitro ,Marek's disease herpesvirus ,medicine.anatomical_structure ,Food Animals ,In vivo ,Cell culture ,medicine ,Animal Science and Zoology - Abstract
SUMMARY Cell culture techniques showed kidney cells from genetically susceptible S-strain chickens exposed to JM-virus to have higher concentrations of Marek's disease (MD) herpesvirus than did those from pen-mates of the relatively resistant C-, K-, and PDRC-strains. There was quantitative correlation between numbers of focal lesions and MD infectivity of cultures. However, factors affecting in vivo infection did not influence in vitro sensitivity. Cultured cells derived from unexposed genetically susceptible or resistant strains of chickens were equally sensitive to MD herpesvirus in vitro. The data provide circumstantial evidence that the cytopathogenic herpesvirus was the etiological agent of MD.
- Published
- 1969
10. Correlations of genetic resistance of chickens to Marek's disease viruses with vaccination protection and in vivoresponse to phytohemaglutinin
- Author
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Gavora, JS, Spencer, JL, Okada, I, Grunder, AA, Griffin, PS, and Sally, E.
- Published
- 1990
- Full Text
- View/download PDF
11. Corn Rootworm: Biology, Ecology, Behavior, and Integrated Management.
- Author
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Meinke LJ and Spencer JL
- Abstract
Species of the beetle genus Diabrotica (Coleoptera: Chrysomelidae) are native to North and South America, with their greatest diversity occurring in neotropical areas [...].
- Published
- 2024
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12. Movement Ecology of Adult Western Corn Rootworm: Implications for Management.
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Sappington TW and Spencer JL
- Abstract
Movement of adult western corn rootworm, Diabrotica virgifera virgifera LeConte, is of fundamental importance to this species' population dynamics, ecology, evolution, and interactions with its environment, including cultivated cornfields. Realistic parameterization of dispersal components of models is needed to predict rates of range expansion, development, and spread of resistance to control measures and improve pest and resistance management strategies. However, a coherent understanding of western corn rootworm movement ecology has remained elusive because of conflicting evidence for both short- and long-distance lifetime dispersal, a type of dilemma observed in many species called Reid's paradox. Attempts to resolve this paradox using population genetic strategies to estimate rates of gene flow over space likewise imply greater dispersal distances than direct observations of short-range movement suggest, a dilemma called Slatkin's paradox. Based on the wide-array of available evidence, we present a conceptual model of adult western corn rootworm movement ecology under the premise it is a partially migratory species. We propose that rootworm populations consist of two behavioral phenotypes, resident and migrant . Both engage in local, appetitive flights, but only the migrant phenotype also makes non-appetitive migratory flights, resulting in observed patterns of bimodal dispersal distances and resolution of Reid's and Slatkin's paradoxes.
- Published
- 2023
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13. Soybean Foliage Consumption Reduces Adult Western Corn Rootworm (Diabrotica virgifera virgifera)(Coleoptera: Chrysomelidae) Survival and Stimulates Flight.
- Author
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Spencer JL, Mabry TR, Levine E, and Isard SA
- Subjects
- Adaptation, Physiological, Animals, Herbivory, Larva, Plants, Genetically Modified, Glycine max, Zea mays, Coleoptera genetics
- Abstract
Western corn rootworm, Diabrotica virgifera virgifera LeConte, biology is tied to the continuous availability of its host (corn, Zea mays L.). Annual rotation of corn with a nonhost, like soybean (Glycine max (L.) Merrill) was a reliable tactic to manage western corn rootworm. Behavioral resistance to annual crop rotation (rotation resistance) allowed some eastern U.S. Corn Belt populations to circumvent rotation by laying eggs in soybean and in cornfields. When active in soybean, rotation-resistant adults commonly consume foliage, in spite of detrimental effects on beetle survival. Rotation-resistant beetle activity in soybean is enabled by the expression of certain proteinases and an adapted gut microbiota that provide limited protection from soybean antiherbivore defenses. We investigated the effects of corn and soybean herbivory on rotation-resistant female survival and initiation of flight using mortality assays and wind tunnel flight tests. Among field-collected females tested with mortality assays, beetles from collection sites in a cornfield survived longer than those from collection sites in a soybean field. However, reduced survival due to soybean herbivory could be restored by consuming corn tissues. Field-collected beetles that fed on a soybean tissue laboratory diet or only water were more likely to fly in a wind tunnel than corn-feeding beetles. Regardless of collection site and laboratory diet, 90.5% of beetles that flew oriented their flights upwind. Diet-related changes in the probability of flight provide a proximate mechanism for interfield movement that facilitates restorative feeding and the survival of females previously engaged in soybean herbivory., (© The Author(s) 2021. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
- Published
- 2021
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14. Accurate crystal structures and chemical properties from NoSpherA2.
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Kleemiss F, Dolomanov OV, Bodensteiner M, Peyerimhoff N, Midgley L, Bourhis LJ, Genoni A, Malaspina LA, Jayatilaka D, Spencer JL, White F, Grundkötter-Stock B, Steinhauer S, Lentz D, Puschmann H, and Grabowsky S
- Abstract
The relationship between the structure and the properties of a drug or material is a key concept of chemistry. Knowledge of the three-dimensional structure is considered to be of such importance that almost every report of a new chemical compound is accompanied by an X-ray crystal structure - at least since the 1970s when diffraction equipment became widely available. Crystallographic software of that time was restricted to very limited computing power, and therefore drastic simplifications had to be made. It is these simplifications that make the determination of the correct structure, especially when it comes to hydrogen atoms, virtually impossible. We have devised a robust and fast system where modern chemical structure models replace the old assumptions, leading to correct structures from the model refinement against standard in-house diffraction data using no more than widely available software and desktop computing power. We call this system NoSpherA2 (Non-Spherical Atoms in Olex2). We explain the theoretical background of this technique and demonstrate the far-reaching effects that the improved structure quality that is now routinely available can have on the interpretation of chemical problems exemplified by five selected examples., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)
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- 2020
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15. Replication of Zika Virus in Human Prostate Cells: A Potential Source of Sexually Transmitted Virus.
- Author
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Spencer JL, Lahon A, Tran LL, Arya RP, Kneubehl AR, Vogt MB, Xavier D, Rowley DR, Kimata JT, and Rico-Hesse RR
- Subjects
- Americas, Flow Cytometry, Humans, Male, Microscopy, Fluorescence, Real-Time Polymerase Chain Reaction, Virus Cultivation, Zika Virus isolation & purification, Zika Virus Infection virology, Epithelial Cells virology, Mesenchymal Stem Cells virology, Prostate virology, Viral Tropism, Virus Replication, Zika Virus physiology
- Abstract
Background: While Zika virus (ZIKV) is mainly transmitted by mosquitoes, numerous cases of sexual transmission have been reported during recent outbreaks. Little is known about which host cell types or entry factors aid in mediating this sexual transmission., Methods: In this study, we investigated ZIKV cell tropism by infecting 2 types of human prostate cells with 3 contemporary ZIKV isolates from persons infected in the Americas. We used real-time quantitative polymerase chain reaction and immunofluorescence analyses to measure infection and flow cytometry to detect entry factor expression., Results: Here we show that ZIKV infects, replicates, and produces infectious virus in prostate stromal mesenchymal stem cells, epithelial cells, and organoids made with a combination of these cells. We also show that prostate cells express several well-characterized flavivirus attachment factors. In contrast, dengue virus does not infect or does not replicate in these prostate cells, although it is known to use similar receptors., Conclusions: Our results indicate that ZIKV favors infection of stromal cells more so than epithelial cells in organoids, possibly indicating a preference for stem cells in general. Overall, these results suggest that ZIKV replication occurs in the human prostate and can account for ZIKV secretion in semen, thus leading to sexual transmission., (© The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)
- Published
- 2018
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16. Selinene Volatiles Are Essential Precursors for Maize Defense Promoting Fungal Pathogen Resistance.
- Author
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Ding Y, Huffaker A, Köllner TG, Weckwerth P, Robert CAM, Spencer JL, Lipka AE, and Schmelz EA
- Subjects
- Biological Assay, Biosynthetic Pathways drug effects, Biosynthetic Pathways genetics, Chromosome Mapping, Fusarium drug effects, Gene Expression Regulation, Plant drug effects, Genetic Linkage, Herbivory drug effects, Plant Diseases microbiology, Plant Proteins metabolism, Plant Roots drug effects, Plant Roots parasitology, RNA, Messenger genetics, RNA, Messenger metabolism, Zea mays enzymology, Zea mays genetics, Disease Resistance drug effects, Fusarium physiology, Plant Diseases immunology, Sesquiterpenes pharmacology, Volatile Organic Compounds pharmacology, Zea mays immunology, Zea mays microbiology
- Abstract
To ensure food security, maize ( Zea mays ) is a model crop for understanding useful traits underlying stress resistance. In contrast to foliar biochemicals, root defenses limiting the spread of disease remain poorly described. To better understand belowground defenses in the field, we performed root metabolomic profiling and uncovered unexpectedly high levels of the sesquiterpene volatile β-selinene and the corresponding nonvolatile antibiotic derivative β-costic acid. The application of metabolite-based quantitative trait locus mapping using biparental populations, genome-wide association studies, and near-isogenic lines enabled the identification of terpene synthase21 ( ZmTps21 ) on chromosome 9 as a β-costic acid pathway candidate gene. Numerous closely examined β-costic acid-deficient inbred lines were found to harbor Zmtps21 pseudogenes lacking conserved motifs required for farnesyl diphosphate cyclase activity. For biochemical validation, a full-length ZmTps21 was cloned, heterologously expressed in Escherichia coli , and demonstrated to cyclize farnesyl diphosphate, yielding β-selinene as the dominant product. Consistent with microbial defense pathways, ZmTps21 transcripts strongly accumulate following fungal elicitation. Challenged field roots containing functional ZmTps21 alleles displayed β-costic acid levels over 100 μg g
-1 fresh weight, greatly exceeding in vitro concentrations required to inhibit the growth of five different fungal pathogens and rootworm larvae ( Diabrotica balteata ). In vivo disease resistance assays, using ZmTps21 and Zmtps21 near-isogenic lines, further support the endogenous antifungal role of selinene-derived metabolites. Involved in the biosynthesis of nonvolatile antibiotics, ZmTps21 exists as a useful gene for germplasm improvement programs targeting optimized biotic stress resistance., (© 2017 American Society of Plant Biologists. All Rights Reserved.)- Published
- 2017
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17. Transition metal complexes of the pyridylphosphine ligand o-C 6 H 4 (CH 2 PPy 2 ) 2 .
- Author
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Vaughan TF and Spencer JL
- Abstract
The synthesis and coordination behaviour of the pyridylphosphine ligand o-C
6 H4 (CH2 PPy2 )2 (Py = 2-pyridyl) are reported. The phosphine selenide was synthesised and the1 JPSe value of 738 Hz indicates the phosphorus atoms have a similar basicity to PPh3 . The ligand reacts with platinum(ii) and palladium(ii) complexes to give simple diphosphine complexes of the type [MX2 (PP)] (M = Pt, X = Cl, I, Me, Et; M = Pd, X = Cl, Me). When the ligand is reacted with chloromethyl(hexa-1,5-diene)platinum the [PtClMe(PP)] complex results, from which a series of unsymmetrical platinum complexes of the type [PtMeL(PP)]+ (L = PPh3 , PTA, SEt2 and pyridine) can be made. This enabled the comparison of the cis and trans influences of a range of ligands. The following cis influence series was compiled based on31 P NMR data of these complexes: Py ≈ Cl > SEt2 > PTA > PPh3 . Reaction of [PtClMe(PP)] with NaCH(SO2 CF3 )2 and carbon monoxide slowly formed an acyl complex, where the CO had inserted in the Pt-Me bond. Attempts to achieve P,P,N chelation, through abstracting the chloride ligand in [PtClMe(PP)], were unsuccessful. When the ligand reacted with platinum(0), palladium(0) and silver(i) complexes the bis-chelated complexes [M(PP)2 ] (M = Pt, Pd) and [Ag(PP)2 ]+ were formed respectively. Reaction of the ligand with [Ir(COD)(μ-Cl)]2 formed [IrCl(PP)(COD)]. When the chloride ligand was abstracted, the pyridyl nitrogens were able to interact with the iridium centre facilitating the isomerisation of the 1,2,5,6-η4 -COD ligand to a 1-κ-4,5,6-η3 -C8 H12 ligand. The X-ray crystal structure of [Ir(1-κ-4,5,6-η3 -C8 H12 )(PPN)]BPh4 confirmed the P,P,N chelation mode of the ligand. In solution, this complex displayed hemilabile behaviour, with the pyridyl nitrogens exchanging at a rate faster than the NMR time scale at room temperature.- Published
- 2016
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18. Patterns of differential gene expression in adult rotation-resistant and wild-type western corn rootworm digestive tracts.
- Author
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Chu CC, Zavala JA, Spencer JL, Curzi MJ, Fields CJ, Drnevich J, Siegfried BD, and Seufferheld MJ
- Abstract
The western corn rootworm (WCR,Diabrotica virgifera virgifera LeConte) is an important pest of corn. Annual crop rotation between corn and soybean disrupts the corn-dependent WCR life cycle and is widely adopted to manage this pest. This strategy selected for rotation-resistant (RR) WCR with reduced ovipositional fidelity to corn. Previous studies revealed that RR-WCR adults exhibit greater tolerance of soybean diets, different gut physiology, and host-microbe interactions compared to rotation-susceptible wild types (WT). To identify the genetic mechanisms underlying these phenotypic changes, a de novo assembly of the WCR adult gut transcriptome was constructed and used for RNA-sequencing analyses of RNA libraries from different WCR phenotypes fed with corn or soybean diets. Global gene expression profiles of WT- and RR-WCR were similar when feeding on corn diets, but different when feeding on soybean. Using network-based methods, we identified gene modules transcriptionally correlated with the RR phenotype. Gene ontology enrichment analyses indicated that the functions of these modules were related to metabolic processes, immune responses, biological adhesion, and other functions/processes that appear to correlate to documented traits in RR populations. These results suggest that gut transcriptomic divergence correlated with brief soybean feeding and other physiological traits may exist between RR- and WT-WCR adults.
- Published
- 2015
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19. Emergence and Abundance of Western Corn Rootworm (Coleoptera: Chrysomelidae) in Bt Cornfields With Structured and Seed Blend Refuges.
- Author
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Hughson SA and Spencer JL
- Subjects
- Animals, Bacillus thuringiensis Toxins, Female, Insecticide Resistance, Male, Population Density, Glycine max, Agriculture methods, Bacterial Proteins, Coleoptera, Endotoxins, Hemolysin Proteins, Zea mays
- Abstract
To slow evolution of western corn rootworm (Diabrotica virgifera virgifera LeConte) resistance to Bt (Bacillus thuringiensis Berliner) corn hybrids, non-Bt "refuges" must be planted within or adjacent to Bt cornfields, allowing susceptible insects to develop without exposure to Bt toxins. Bt-susceptible adults from refuges are expected to find and mate with resistant adults that have emerged from Bt corn, reducing the likelihood that Bt-resistant offspring are produced. The spatial and temporal distribution of adults in four refuge treatments (20, 5, and 0% structured refuges and 5% seed blend) and adjacent soybean fields was compared from 2010 to 2012. Adult emergence (adults/trap/day) from refuge corn in structured refuge treatments was greater than that from Bt corn, except during the post-pollination period of corn phenology when emergence from refuge and Bt plants was often the same. Abundance of free-moving adults was greatest in and near refuge rows in structured refuge treatments during vegetative and pollination periods. By post-pollination, adult abundance became evenly distributed. In contrast, adult abundance in 5% seed blends and 0% refuges was evenly distributed, or nearly so, across plots throughout the season. The persistent concentration of adults in refuge rows suggests that structured refuge configurations may not facilitate the expected mixing of adults from refuge and Bt corn. Seed blends produce uniform distributions of adults across the field that may facilitate mating between Bt and refuge adults and ultimately delay the evolution of Bt resistance., (© The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)
- Published
- 2015
- Full Text
- View/download PDF
20. Crystal structure of bis-[1,3-bis-(di-phenyl-phosphan-yl)propane-κ(2) P,P']platinum(II) dichloride chloro-form penta-solvate.
- Author
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Anderson BG, Hoyte SA, and Spencer JL
- Abstract
In the title compound, [Pt{Ph2P(CH2)3PPh2}2]Cl2·5CHCl3, the Pt(II) cations, located on a centre of inversion, is coordinated by two chelating diphosphane ligands in a geometry which is close to square-planar. The chelate rings adopt a chair conformation. The Pt(II) cations are arranged in layers separated by Cl(-) anions as well as CHCl3 solvent mol-ecules. While this complex has been reported previously [Anderson et al. (1983 ▶). Inorg. Chim. Acta, 76, L251-L252], this is the first time a structure has been determined.
- Published
- 2015
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21. Modeling a western corn rootworm, Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae), maturation delay and resistance evolution in Bt corn.
- Author
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Kang JK, Krupke CH, Murphy AF, Spencer JL, Gray ME, and Onstad DW
- Subjects
- Animals, Coleoptera growth & development, Computer Simulation, Female, Larva, Male, Pest Control, Biological, Sex Ratio, Bacillus thuringiensis genetics, Coleoptera drug effects, Insecticide Resistance, Plants, Genetically Modified, Zea mays genetics
- Abstract
Background: Emergence delay and female-skewed sex ratios among adults of Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) from Bt corn have been reported in field studies. The authors used a simulation model to study the effect of a maturation delay and a female-skewed sex ratio for D. v. virgifera emerging from Bt corn on the evolution of Bt resistance., Results: The effect of skewed toxin mortality in one sex on evolution of Bt resistance was insignificant. An emergence delay among resistant beetles from Bt corn slowed resistance evolution. A shift in the time of emergence for homozygous susceptible beetles from Bt corn did not have a significant effect on the evolution of Bt resistance in D. v. virgifera., Conclusion: This simulation study suggested that skewed toxin mortality in one sex and an emergence delay for beetles in Bt corn are not major concerns for managing resistance by D. v. virgifera to single-toxin or pyramided Bt corn., (© 2013 Society of Chemical Industry.)
- Published
- 2014
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22. The coordination chemistry of pentafluorophenylphosphino pincer ligands to platinum and palladium.
- Author
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Anderson BG and Spencer JL
- Abstract
The synthesis of electron-poor PCP pincer ligands 1,3-((C6F5)2PO)2C6H4, 1,3-((C6F5)2PCH2)2C6H4, and 1-((C6F5)2PO)-3-(tBu2PCH2)C6H4, and their coordination chemistry to platinum and palladium is described. The most electron-poor ligand 1,3-((C6F5)2PO)2C6H4 (POCOPH) reacts with Group 10 metal chloride precursors to form a range of unusual cis, trans-dimers of the type κ(2)-P,P-[(POCOPH)MCl(L)]2 (M = Pt, Pd; L = Cl, Me), which undergo metallation to form [(POCOP)MCl] pincer complexes only under prolonged thermolysis. The formation of such cis,trans-dimers during pincer complex formation can be mitigated through the use of starting materials with more strongly binding ancillary ligands, improving the overall rate of ligand metallation. Carbonyl complexes of the type [(PCP)M(CO)](+) were synthesised from the pincer chloride complexes by halide abstraction, and displayed large ν(C-O) values, from 2170-2111 cm(-1), confirming the electron-poor nature of the compounds. The [(PCP)Pd(CO)](+) complexes also demonstrated the ability to reversibly bind carbon monoxide both in solution and the solid state, with the rate of decarbonylation increasing with increasing wavenumber for the C-O stretch., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2014
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23. Differential effects of RNAi treatments on field populations of the western corn rootworm.
- Author
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Chu CC, Sun W, Spencer JL, Pittendrigh BR, and Seufferheld MJ
- Subjects
- Animals, Base Sequence, Gastrointestinal Tract metabolism, Genes, Insect, Genetic Variation, Larva genetics, Molecular Sequence Data, Glycine max, Cathepsin L genetics, Coleoptera genetics, Insect Proteins genetics, Pest Control, Biological, RNA Interference
- Abstract
RNA interference (RNAi) mediated crop protection against insect pests is a technology that is greatly anticipated by the academic and industrial pest control communities. Prior to commercialization, factors influencing the potential for evolution of insect resistance to RNAi should be evaluated. While mutations in genes encoding the RNAi machinery or the sequences targeted for interference may serve as a prominent mechanism of resistance evolution, differential effects of RNAi on target pests may also facilitate such evolution. However, to date, little is known about how variation of field insect populations could influence the effectiveness of RNAi treatments. To approach this question, we evaluated the effects of RNAi treatments on adults of three western corn rootworm (WCR; Diabrotica virgifera virgifera LeConte) populations exhibiting different levels of gut cysteine protease activity, tolerance of soybean herbivory, and immune gene expression; two populations were collected from crop rotation-resistant (RR) problem areas and one from a location where RR was not observed (wild type; WT). Our results demonstrated that RNAi targeting DvRS5 (a highly expressed cysteine protease gene) reduced gut cysteine protease activity in all three WCR populations. However, the proportion of the cysteine protease activity that was inhibited varied across populations. When WCR adults were treated with double-stranded RNA of an immune gene att1, different changes in survival among WT and RR populations on soybean diets occurred. Notably, for both genes, the sequences targeted for RNAi were the same across all populations examined. These findings indicate that the effectiveness of RNAi treatments could vary among field populations depending on their physiological and genetic backgrounds and that the consistency of an RNAi trait's effectiveness on phenotypically different populations should be considered or tested prior to wide deployment. Also, genes that are potentially subjected to differential selection in the field should be avoided for RNAi-based pest control., (Published by Elsevier Inc.)
- Published
- 2014
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24. Synthesis and characterisation of novel o-xylene-based P,E ligands.
- Author
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Allan KM and Spencer JL
- Abstract
A range of novel hybrid ligands of the type, o-C6H4(CH2PBu(t)2)(CH2E) (E = P(C6F5)2, SBu(t), SPh, S(O)Bu(t), NR2, SiPh2H), have been synthesised in two or three steps from the common substrate, o-C6H4{CH2PBu(t)2(BH3)}(CH2Cl). The initial step involved treatment of the substrate with the appropriate nucleophilic reagent, or preparation of a Grignard reagent from o-C6H4{CH2PBu(t)2(BH3)}(CH2Cl) and reaction with the appropriate electrophile. In most cases, this versatile strategy produced air-stable crystalline ligand precursors. Phosphine deprotection was achieved via one of three methods, dependent upon the properties of the second functional group. An alternative synthesis of the known ligand, o-C6H4(CH2PBu(t)2)(CH2PPh2), is also presented.
- Published
- 2014
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25. STRAP PTM: Software Tool for Rapid Annotation and Differential Comparison of Protein Post-Translational Modifications.
- Author
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Spencer JL, Bhatia VN, Whelan SA, Costello CE, and McComb ME
- Subjects
- Amino Acid Sequence, Humans, Molecular Sequence Data, Peptides chemistry, Tandem Mass Spectrometry, Molecular Sequence Annotation, Protein Processing, Post-Translational, Software
- Abstract
The identification of protein post-translational modifications (PTMs) is an increasingly important component of proteomics and biomarker discovery, but very few tools exist for performing fast and easy characterization of global PTM changes and differential comparison of PTMs across groups of data obtained from liquid chromatography-tandem mass spectrometry experiments. STRAP PTM (Software Tool for Rapid Annotation of Proteins: Post-Translational Modification edition) is a program that was developed to facilitate the characterization of PTMs using spectral counting and a novel scoring algorithm to accelerate the identification of differential PTMs from complex data sets. The software facilitates multi-sample comparison by collating, scoring, and ranking PTMs and by summarizing data visually. The freely available software (beta release) installs on a PC and processes data in protXML format obtained from files parsed through the Trans-Proteomic Pipeline. The easy-to-use interface allows examination of results at protein, peptide, and PTM levels, and the overall design offers tremendous flexibility that provides proteomics insight beyond simple assignment and counting.
- Published
- 2013
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26. Aerosol transmission of an avian influenza H9N2 virus with a tropism for the respiratory tract of chickens.
- Author
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Guan J, Fu Q, Chan M, and Spencer JL
- Subjects
- Administration, Intranasal veterinary, Administration, Oral, Aerosols administration & dosage, Animals, Chick Embryo, Cloaca virology, Influenza in Birds virology, Oropharynx virology, Polymerase Chain Reaction veterinary, Poultry Diseases virology, Specific Pathogen-Free Organisms, Tropism, Chickens, Influenza A Virus, H9N2 Subtype physiology, Influenza in Birds transmission, Poultry Diseases transmission, Respiratory System virology
- Abstract
A low pathogenic avian influenza virus (LPAI H9N2) was administered to 3-wk-old chickens by aerosol exposure, intranasal inoculation, and by oral inoculation. Tests for virus were by in ovo assay and by real-time reverse-transcriptase PCR. The aerosol dosage was determined by aerosolizing virus into a chamber when it was empty and when it contained chickens. Air was collected and the amount of virus inhaled was estimated to be about 18% of the total body uptake. In transmission studies, tests for virus were conducted on oropharyngeal or cloacal swabs. The 50% infectious dose (ID50) for aerosolized virus was about 2 log 10 and 5 log 10 lower than by nasal or oral inoculation, respectively. The recovery rate was higher from swabs of the oropharyngeal region than from the cloacal region (P < 0.05). For horizontal transmission studies, uninfected chickens were held in isolators with seeders that had been inoculated intranasally with the H9N2 virus. Chickens exposed by indirect contact were separated by screens from the seeders. In another isolator those directly exposed were intermingled with the seeders. During the 10-day test period, none of the chickens developed symptoms of disease, but infection was detected as early as 4 and 7 days in the indirectly and directly exposed groups, respectively. These findings suggested that aerosol transmission of viruses similar to LPAI H9N2 could efficiently occur, at least over short distances.
- Published
- 2013
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27. Wing shape and size of the western corn rootworm (Coleoptera: Chrysomelidae) is related to sex and resistance to soybean-maize crop rotation.
- Author
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Mikac KM, Douglas J, and Spencer JL
- Subjects
- Animals, Female, Male, Midwestern United States, Phenotype, Sex Characteristics, Wings, Animal anatomy & histology, Agriculture methods, Coleoptera anatomy & histology, Coleoptera genetics, Glycine max growth & development, Zea mays growth & development
- Abstract
The western corn rootworm, Diabrotica virgifera virgifera LeConte, is a major pest of maize in the United States and more recently, Europe. Understanding the dispersal dynamics of this species will provide crucial information for its management. This study used geometric morphometric analysis of hind wing venation based on 13 landmarks in 223 specimens from nine locations in Illinois, Nebraska, Iowa, and Missouri, to assess whether wing shape and size differed between rotated and continuously grown maize where crop rotation-resistant and susceptible individuals are found, respectively. Before assessing differences between rotation-resistant and susceptible individuals, sexual dimorphism was investigated. No significant difference in wing (centroid) size was found between males and females; however, females had significantly different shaped (more elongated) wings compared with males. Wing shape and (centroid) size were significantly larger among individuals from rotated maize where crop-rotation resistance was reported; however, cross-validation of these results revealed that collection site resistance status was an only better than average predictor of shape in males and females. This study provides preliminary evidence of wing shape and size differences in D. v. virgifera from rotated versus continuous maize. Further study is needed to confirm whether wing shape and size can be used to track the movement of rotation-resistant individuals and populations as a means to better inform management strategies.
- Published
- 2013
- Full Text
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28. Information governance. The price of data sharing.
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Spencer JL
- Subjects
- European Union, Humans, State Medicine, United Kingdom, Health Information Management, Medical Record Linkage
- Published
- 2013
29. Gut bacteria facilitate adaptation to crop rotation in the western corn rootworm.
- Author
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Chu CC, Spencer JL, Curzi MJ, Zavala JA, and Seufferheld MJ
- Subjects
- Acetates, Animals, Base Sequence, Cluster Analysis, Coleoptera physiology, Cyclopentanes, Cysteine Proteinase Inhibitors analysis, DNA, Ribosomal genetics, Herbivory physiology, Host-Pathogen Interactions physiology, Kaplan-Meier Estimate, Metagenome genetics, Molecular Sequence Data, Oxylipins, Plant Leaves chemistry, Sequence Analysis, DNA, United States, Adaptation, Physiological physiology, Coleoptera microbiology, Cysteine Proteinase Inhibitors metabolism, Insecticide Resistance physiology, Metagenome physiology, Glycine max chemistry, Zea mays parasitology
- Abstract
Insects are constantly adapting to human-driven landscape changes; however, the roles of their gut microbiota in these processes remain largely unknown. The western corn rootworm (WCR, Diabrotica virgifera virgifera LeConte) (Coleoptera: Chrysomelidae) is a major corn pest that has been controlled via annual rotation between corn (Zea mays) and nonhost soybean (Glycine max) in the United States. This practice selected for a "rotation-resistant" variant (RR-WCR) with reduced ovipositional fidelity to cornfields. When in soybean fields, RR-WCRs also exhibit an elevated tolerance of antiherbivory defenses (i.e., cysteine protease inhibitors) expressed in soybean foliage. Here we show that gut bacterial microbiota is an important factor facilitating this corn specialist's (WCR's) physiological adaptation to brief soybean herbivory. Comparisons of gut microbiota between RR- and wild-type WCR (WT-WCR) revealed concomitant shifts in bacterial community structure with host adaptation to soybean diets. Antibiotic suppression of gut bacteria significantly reduced RR-WCR tolerance of soybean herbivory to the level of WT-WCR, whereas WT-WCR were unaffected. Our findings demonstrate that gut bacteria help to facilitate rapid adaptation of insects in managed ecosystems.
- Published
- 2013
- Full Text
- View/download PDF
30. Heparan sulfate-protein binding specificity.
- Author
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Nugent MA, Zaia J, and Spencer JL
- Subjects
- Animals, Antithrombin III chemistry, Antithrombin III metabolism, Fibroblast Growth Factors chemistry, Fibroblast Growth Factors metabolism, Heparitin Sulfate chemistry, Humans, Leukocyte Elastase antagonists & inhibitors, Leukocyte Elastase metabolism, Protein Binding, Proteins chemistry, Heparitin Sulfate metabolism, Proteins metabolism
- Abstract
Heparan sulfate (HS) represents a large class of linear polysaccharides that are required for the function of all mammalian physiological systems. HS is characterized by a repeating disaccharide backbone that is subject to a wide range of modifications, making this class of macromolecules arguably the most information dense in all of biology. The majority of HS functions are associated with the ability to bind and regulate a wide range of proteins. Indeed, recent years have seen an explosion in the discovery of new activities for HS where it is now recognized that this class of glycans functions as co-receptors for growth factors and cytokines, modulates cellular uptake of lipoproteins, regulates protease activity, is critical to amyloid plaque formation, is used by opportunistic pathogens to enter cells, and may even participate in epigenetic regulation. This review will discuss the current state of understanding regarding the specificity of HS-protein binding and will describe the concept that protein binding to HS depends on the overall organization of domains within HS rather than fine structure.
- Published
- 2013
- Full Text
- View/download PDF
31. Abnormally high digestive enzyme activity and gene expression explain the contemporary evolution of a Diabrotica biotype able to feed on soybeans.
- Author
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Curzi MJ, Zavala JA, Spencer JL, and Seufferheld MJ
- Abstract
Western corn rootworm (Diabrotica virgifera) (WCR) depends on the continuous availability of corn. Broad adoption of annual crop rotation between corn (Zea mays) and nonhost soybean (Glycine max) exploited WCR biology to provide excellent WCR control, but this practice dramatically reduced landscape heterogeneity in East-central Illinois and imposed intense selection pressure. This selection resulted in behavioral changes and "rotation-resistant" (RR) WCR adults. Although soybeans are well defended against Coleopteran insects by cysteine protease inhibitors, RR-WCR feed on soybean foliage and remain long enough to deposit eggs that will hatch the following spring and larvae will feed on roots of planted corn. Other than documenting changes in insect mobility and egg laying behavior, 15 years of research have failed to identify any diagnostic differences between wild-type (WT)- and RR-WCR or a mechanism that allows for prolonged RR-WCR feeding and survival in soybean fields. We documented differences in behavior, physiology, digestive protease activity (threefold to fourfold increases), and protease gene expression in the gut of RR-WCR adults. Our data suggest that higher constitutive activity levels of cathepsin L are part of the mechanism that enables populations of WCR to circumvent soybean defenses, and thus, crop rotation. These new insights into the mechanism of WCR tolerance of soybean herbivory transcend the issue of RR-WCR diagnostics and management to link changes in insect gut proteolytic activity and behavior with landscape heterogeneity. The RR-WCR illustrates how agro-ecological factors can affect the evolution of insects in human-altered ecosystems.
- Published
- 2012
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32. Hot-injection synthesis of iron/iron oxide core/shell nanoparticles for T2 contrast enhancement in magnetic resonance imaging.
- Author
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Herman DA, Ferguson P, Cheong S, Hermans IF, Ruck BJ, Allan KM, Prabakar S, Spencer JL, Lendrum CD, and Tilley RD
- Subjects
- Contrast Media chemistry, Ferric Compounds chemistry, Hot Temperature, Nanoparticles ultrastructure, Nanotechnology methods, Contrast Media chemical synthesis, Ferric Compounds chemical synthesis, Magnetic Resonance Imaging methods, Nanoparticles chemistry
- Abstract
Here we report a new, bench-top synthesis for iron/iron oxide core/shell nanoparticles via the thermal decomposition of Fe(η(5)-C(6)H(3)Me(4))(2). The iron/iron oxide core/shell nanoparticles are superparamagnetic at room temperature and show improved negative contrast in T(2)-weighted MR imaging compared to pure iron oxides nanoparticles, and have a transverse relaxivity (r(2)) of 332 mM(-1) s(-1).
- Published
- 2011
- Full Text
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33. Dynamics of enzymatic digestion of elastic fibers and networks under tension.
- Author
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Araújo AD, Majumdar A, Parameswaran H, Yi E, Spencer JL, Nugent MA, and Suki B
- Subjects
- Algorithms, Animals, Animals, Newborn, Anisotropy, Aorta cytology, Cells, Cultured, Elasticity, Extracellular Matrix enzymology, Kinetics, Models, Biological, Models, Chemical, Muscle, Smooth, Vascular cytology, Pancreatic Elastase metabolism, Rats, Rats, Sprague-Dawley, Stress, Mechanical, Elastin chemistry, Elastin metabolism, Extracellular Matrix metabolism, Muscle, Smooth, Vascular metabolism
- Abstract
We study the enzymatic degradation of an elastic fiber under tension using an anisotropic random-walk model coupled with binding-unbinding reactions that weaken the fiber. The fiber is represented by a chain of elastic springs in series along which enzyme molecules can diffuse. Numerical simulations show that the fiber stiffness decreases exponentially with two distinct regimes. The time constant of the first regime decreases with increasing tension. Using a mean field calculation, we partition the time constant into geometrical, chemical and externally controllable factors, which is corroborated by the simulations. We incorporate the fiber model into a multiscale network model of the extracellular matrix and find that network effects do not mask the exponential decay of stiffness at the fiber level. To test these predictions, we measure the force relaxation of elastin sheets stretched to 20% uniaxial strain in the presence of elastase. The decay of force is exponential and the time constant is proportional to the inverse of enzyme concentration in agreement with model predictions. Furthermore, the fragment mass released into the bath during digestion is linearly related to enzyme concentration that is also borne out in the model. We conclude that in the complex extracellular matrix, feedback between the local rate of fiber digestion and the force the fiber carries acts to attenuate any spatial heterogeneity of digestion such that molecular processes manifest directly at the macroscale. Our findings can help better understand remodeling processes during development or in disease in which enzyme concentrations and/or mechanical forces become abnormal.
- Published
- 2011
- Full Text
- View/download PDF
34. Innovation. Europe flies the flag for new ideas.
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Spencer JL
- Subjects
- Delivery of Health Care economics, Efficiency, Organizational, Europe, Financing, Government organization & administration, State Medicine, Delivery of Health Care organization & administration, Diffusion of Innovation, Quality of Health Care
- Published
- 2011
35. Seeds of change: corn seed mixtures for resistance management and integrated pest management.
- Author
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Onstad DW, Mitchell PD, Hurley TM, Lundgren JG, Porter RP, Krupke CH, Spencer JL, DiFonzo CD, Baute TS, Hellmich RL, Buschman LL, Hutchison WD, and Tooker JF
- Subjects
- Animals, Humans, Behavior, Animal, Insect Control, Insecticide Resistance, Plants, Genetically Modified, Seeds, Zea mays genetics
- Abstract
The use of mixtures of transgenic insecticidal seed and nontransgenic seed to provide an in-field refuge for susceptible insects in insect-resistance-management (IRM) plans has been considered for at least two decades. However, the U.S. Environmental Protection Agency has only recently authorized the practice. This commentary explores issues that regulators, industry, and other stakeholders should consider as the use of biotechnology increases and seed mixtures are implemented as a major tactic for IRM. We discuss how block refuges and seed mixtures in transgenic insecticidal corn, Zea mays L., production will influence integrated pest management (IPM) and the evolution of pest resistance. We conclude that seed mixtures will make pest monitoring more difficult and that seed mixtures may make IRM riskier because of larval behavior and greater adoption of insecticidal corn. Conversely, block refuges present a different suite of risks because of adult pest behavior and the lower compliance with IRM rules expected from farmers. It is likely that secondary pests not targeted by the insecticidal corn as well as natural enemies will respond differently to block refuges and seed mixtures.
- Published
- 2011
- Full Text
- View/download PDF
36. Oviposition behaviors in relation to rotation resistance in the western corn rootworm.
- Author
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Knolhoff LM, Glas JJ, Spencer JL, and Berenbaum MR
- Subjects
- Agriculture methods, Animals, Cues, Diet, Female, Locomotion, Volatile Organic Compounds, Coleoptera physiology, Host Specificity, Oviposition, Glycine max parasitology, Zea mays parasitology
- Abstract
Across a large area of the midwestern United States Corn Belt, the western corn rootworm beetle (Diabrotica virgifera virgifera LeConte, Coleoptera: Chrysomelidae) exhibits behavioral resistance to annual crop rotation. Resistant females exhibit increased locomotor activity and frequently lay eggs in soybean (Glycine max L.) fields, although they also lay eggs in fields of corn (Zea mays L.) and other locations. The goals of this study were (1) to determine whether there were any differences in ovipositional behavior and response to plant cues between individual rotation-resistant and wild-type females in the laboratory and (2) to examine the roles of, and interaction between, host volatiles, diet, and locomotor behavior as they related to oviposition. Because rootworm females lay eggs in the soil, we also examined the influence of host plant roots on behavior. In the first year of the study, rotation-resistant beetles were significantly more likely to lay eggs in the presence of soybean foliage and to feed on soybean leaf discs than wild-type females, but this difference was not observed in the second year. Oviposition by rotation-resistant females was increased in the presence of soybean roots, but soybean herbivory did not affect ovipositional choice. Conversely, ovipositional choice of wild-type females was not affected by the presence or identity of host plant roots encountered, and wild-type females consuming soybean foliage were more likely to lay eggs., (© 2010 Entomological Society of America)
- Published
- 2010
- Full Text
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37. Cellular and subcellular localization of estrogen and progestin receptor immunoreactivities in the mouse hippocampus.
- Author
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Mitterling KL, Spencer JL, Dziedzic N, Shenoy S, McCarthy K, Waters EM, McEwen BS, and Milner TA
- Subjects
- Animals, CA1 Region, Hippocampal metabolism, Estrous Cycle physiology, Female, Hippocampus ultrastructure, Interneurons metabolism, Interneurons ultrastructure, Intracellular Space metabolism, Male, Mice, Mice, Inbred C57BL, Neuroglia metabolism, Neuroglia ultrastructure, Neurons metabolism, Pyramidal Cells metabolism, Pyramidal Cells ultrastructure, Sex Characteristics, Estrogen Receptor alpha metabolism, Estrogen Receptor beta metabolism, Hippocampus metabolism, Receptors, Progesterone metabolism
- Abstract
Estrogen receptor-alpha (ERalpha), estrogen receptor-beta (ERbeta), and progestin receptor (PR) immunoreactivities are localized to extranuclear sites in the rat hippocampal formation. Because rats and mice respond differently to estradiol treatment at a cellular level, the present study examined the distribution of ovarian hormone receptors in the dorsal hippocampal formation of mice. For this, antibodies to ERalpha, ERbeta, and PR were localized by light and electron immunomicroscopy in male and female mice across the estrous cycle. Light microscopic examination of the mouse hippocampal formation showed sparse nuclear ERalpha and PR immunoreactivity (-ir) most prominently in the CA1 region and diffuse ERbeta-ir primarily in the CA1 pyramidal cell layer as well as in a few interneurons. Ultrastructural analysis additionally revealed discrete extranuclear ERalpha-, ERbeta-, and PR-ir in neuronal and glial profiles throughout the hippocampal formation. Although extranuclear profiles were detected in all animal groups examined, the amount and types of profiles varied with sex and estrous cycle phase. ERalpha-ir was highest in diestrus females, particularly in dendritic spines, axons, and glia. Similarly, ERbeta-ir was highest in estrus and diestrus females, mainly in dendritic spines and glia. Conversely, PR-ir was highest during proestrus, mostly in axons. Except for very low levels of extranuclear ERbeta-ir in mossy fiber terminals in mice, the labeling patterns in the mice for all three antibodies were similar to the ultrastructural labeling found previously in rats, suggesting that regulation of these receptors is well conserved across the two species.
- Published
- 2010
- Full Text
- View/download PDF
38. A human surfactant peptide-elastase inhibitor construct as a treatment for emphysema.
- Author
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Guarnieri F, Spencer JL, Lucey EC, Nugent MA, and Stone PJ
- Subjects
- Animals, Disease Models, Animal, Emphysema pathology, Female, Humans, Mice, Mice, Inbred C57BL, Molecular Structure, Pancreatic Elastase metabolism, Peptides chemical synthesis, Protease Inhibitors chemical synthesis, Substrate Specificity, Surface-Active Agents chemical synthesis, Emphysema drug therapy, Pancreatic Elastase antagonists & inhibitors, Peptides therapeutic use, Protease Inhibitors therapeutic use, Surface-Active Agents therapeutic use
- Abstract
Two million Americans suffer from pulmonary emphysema, costing $2.5 billion/year and contributing to 100,000 deaths/year. Emphysema is thought to result from an imbalance between elastase and endogenous inhibitors of elastase, leading to tissue destruction and a loss of alveoli. Decades of research have still not resulted in an effective treatment other than stopping cigarette smoking, a highly addictive behavior. On the basis of our previous work, we hypothesize that small molecule inhibitors of human neutrophil elastase are ineffective because of rapid clearance from the lungs. To develop a long-acting elastase inhibitor with a lung pharmacodynamic profile that has minimal immunogenicity, we covalently linked an elastase inhibitor, similar to a trifluoro inhibitor that was used in clinical trials, to a 25-amino-acid fragment of human surfactant peptide B. We used this construct to prevent human neutrophil elastase-induced emphysema in a rodent model. The elastase inhibitor alone, although in a 70-fold molar excess to elastase in a mixture with <0.6% residual elastase activity, provided no protection from elastase-induced emphysema. Covalently combining an endogenous peptide from the target organ with a synthetic small molecule inhibitor is a unique way of endowing an active compound with the pharmacodynamic profile needed to create in vivo efficacy.
- Published
- 2010
- Full Text
- View/download PDF
39. Infectious bursal disease virus as a surrogate for studies on survival of various poultry viruses in compost.
- Author
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Guan J, Chan M, Brooks BW, and Spencer JL
- Subjects
- Animals, Chlorocebus aethiops, Polymerase Chain Reaction methods, Polymerase Chain Reaction veterinary, Vero Cells, Infectious bursal disease virus physiology, Poultry virology, Soil, Soil Microbiology
- Abstract
Infectious bursal disease virus (IBDV) is resistant to many environmental stresses and often persists on farms for months. This study investigated survival of a vaccine strain of IBDV in the bursa of Fabricius and splenic tissue from experimentally infected chickens and in splenic tissue and manure that had been inoculated with the virus. The specimens buried in compost were contained within nylon mesh bags, and the tissues were enclosed within the abdominal cavity of chicken carcasses. Extracts of composted specimens were inoculated into Vero cell cultures, and real-time reverse transcriptase PCR was used to quantify the virus in the cultures. By day 7 in compost, the temperature had been slightly above 55 C for 2.6 days and IBDV had been inactivated in specimens that had been inoculated with virus but had survived in tissues that had been taken from infected chickens. By day 14, the temperature had been above 55 C for 8.8 days and the virus was inactivated in all specimens. The results suggest that composting of poultry carcasses and manure would help to break the cycle of infection with IBDV and that the virus could be valuable as a surrogate for predicting the inactivation of less resistant viruses during composting.
- Published
- 2010
- Full Text
- View/download PDF
40. The fate of recombinant plasmids during composting of organic wastes.
- Author
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Guan J, Chan M, and Spencer JL
- Subjects
- Animals, Chickens, DNA, Recombinant analysis, Soil analysis, Soil Microbiology, Temperature, Transgenes, Escherichia coli genetics, Manure analysis, Manure microbiology, Plasmids analysis, Refuse Disposal methods
- Abstract
Composting was investigated as a means for safe disposal of organic waste containing bacteria that carry transgenes in recombinant plasmids. To generate model recombinant plasmids, a mobile IncQ plasmid, RSF1010, and a non-mobile plasmid, pGFP, were genetically modified to carry a DNA segment encoding both green fluorescent protein and kanamycin resistance and were designated as RSF1010-GFPK and pGFPK. Escherichia coli (E. coli) C600 harboring these plasmids were inoculated into chicken manure specimens that were placed in compost at 20 and 60 cm from the bottom of a 1.0-m high compost bin. Control specimens were held at ambient temperature. By day 10, compost temperatures at the lower and upper levels of the bin had reached 45.3 and 61.5 degrees C, respectively, and at both levels the target E. coli had been inactivated and the plasmids had lost their capacity to be transformed or mobilized. Furthermore, based on real time Polymerase chain reaction (PCR), the transgene fragments along with the host chromosomal DNA fragment from specimens at the upper level had been degraded beyond the detection limit. However, at the lower level where temperatures remained below 48 degrees C these fragment persisted to day 21. At ambient temperatures (0-8 degrees C), the E. coli, plasmids and the transgene fragments persisted in manure specimens throughout the 21 day test period. The study showed the potential for composting as a safe procedure for disposal of bacteria carrying transgenes in recombinant plasmids.
- Published
- 2010
- Full Text
- View/download PDF
41. BDNF variant Val66Met interacts with estrous cycle in the control of hippocampal function.
- Author
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Spencer JL, Waters EM, Milner TA, Lee FS, and McEwen BS
- Subjects
- Animals, Behavior, Animal, Brain-Derived Neurotrophic Factor chemistry, Brain-Derived Neurotrophic Factor genetics, Female, Genotype, Mice, Brain-Derived Neurotrophic Factor physiology, Estrus physiology, Hippocampus physiology, Methionine genetics, Valine genetics
- Abstract
Natural fluctuations in circulating estradiol are associated with behavioral changes, including severe disturbances in mood and cognition in some women. Common genetic variation in some of the molecular mediators of estradiol effects on these behaviors, in brain regions such as the hippocampus, may explain individual variation in estradiol effects on behavior. We tested whether the common human variant BDNF Val66Met interacts with estradiol in the control of hippocampal function in cycling female mice homozygous for the wild-type Val or BDNF Met variant. BDNF Met increased anxiety behavior, impaired memory, and increased expression of BDNF and its receptor TrkB in the hippocampal formation. BDNF Met also dramatically altered the fluctuation of spatial memory, hippocampal Akt phosphorylation, and PSD-95 protein expression across the estrous cycle. The variant BDNF Val66Met should therefore be considered as a strong candidate for mediating genetic differences in ovarian steroid-related behavioral changes and disorders.
- Published
- 2010
- Full Text
- View/download PDF
42. A computational approach for deciphering the organization of glycosaminoglycans.
- Author
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Spencer JL, Bernanke JA, Buczek-Thomas JA, and Nugent MA
- Subjects
- Algorithms, Animals, Binding Sites, Cell Line, Cells, Cultured, Disaccharides analysis, Disaccharides metabolism, Epithelial Cells chemistry, Epithelial Cells cytology, Fibroblasts chemistry, Fibroblasts cytology, Fourier Analysis, Glycosaminoglycans analysis, Glycosaminoglycans metabolism, Heparin Lyase metabolism, Heparitin Sulfate analysis, Heparitin Sulfate chemistry, Heparitin Sulfate metabolism, Hexuronic Acids analysis, Hexuronic Acids chemistry, Molecular Structure, Rats, Spectroscopy, Fourier Transform Infrared, Structure-Activity Relationship, Disaccharides chemistry, Glycosaminoglycans chemistry, Models, Chemical, Software
- Abstract
Background: Increasing evidence has revealed important roles for complex glycans as mediators of normal and pathological processes. Glycosaminoglycans are a class of glycans that bind and regulate the function of a wide array of proteins at the cell-extracellular matrix interface. The specific sequence and chemical organization of these polymers likely define function; however, identification of the structure-function relationships of glycosaminoglycans has been met with challenges associated with the unique level of complexity and the nontemplate-driven biosynthesis of these biopolymers., Methodology/principal Findings: To address these challenges, we have devised a computational approach to predict fine structure and patterns of domain organization of the specific glycosaminoglycan, heparan sulfate (HS). Using chemical composition data obtained after complete and partial digestion of mixtures of HS chains with specific degradative enzymes, the computational analysis produces populations of theoretical HS chains with structures that meet both biosynthesis and enzyme degradation rules. The model performs these operations through a modular format consisting of input/output sections and three routines called chainmaker, chainbreaker, and chainsorter. We applied this methodology to analyze HS preparations isolated from pulmonary fibroblasts and epithelial cells. Significant differences in the general organization of these two HS preparations were observed, with HS from epithelial cells having a greater frequency of highly sulfated domains. Epithelial HS also showed a higher density of specific HS domains that have been associated with inhibition of neutrophil elastase. Experimental analysis of elastase inhibition was consistent with the model predictions and demonstrated that HS from epithelial cells had greater inhibitory activity than HS from fibroblasts., Conclusions/significance: This model establishes the conceptual framework for a new class of computational tools to use to assess patterns of domain organization within glycosaminoglycans. These tools will provide a means to consider high-level chain organization in deciphering the structure-function relationships of polysaccharides in biology.
- Published
- 2010
- Full Text
- View/download PDF
43. Degradation of foot-and-mouth disease virus during composting of infected pig carcasses.
- Author
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Guan J, Chan M, Grenier C, Brooks BW, Spencer JL, Kranendonk C, Copps J, and Clavijo A
- Subjects
- Animals, Chickens, Foot-and-Mouth Disease Virus genetics, Foot-and-Mouth Disease Virus physiology, Manure, RNA, Viral genetics, Skin virology, Soil, Swine, Temperature, Time Factors, Tissue Culture Techniques, Wood, Foot-and-Mouth Disease virology, Foot-and-Mouth Disease Virus isolation & purification, Medical Waste Disposal methods, Virus Inactivation
- Abstract
The objective of this study was to investigate the inactivation and degradation of foot-and-mouth disease (FMD) virus during composting of infected pig carcasses as measured by virus isolation in tissue culture and by real-time reverse transcriptase polymerase chain reaction (RRT-PCR). Three FMD-infected pig carcasses were composted in a mixture of chicken manure and wood shavings in a biocontainment level 3 facility. Compost temperatures had reached 50 degrees C and 70 degrees C by days 10 and 19, respectively. Under these conditions, FMD virus was inactivated in specimens in compost by day 10 and the viral RNA was degraded in skin and internal organ tissues by day 21. In comparison, at ambient temperatures close to 20 degrees C, FMD virus survived to day 10 in the skin tissue specimen from the pig that had the highest initial level of viral RNA in its tissues and the viral RNA persisted to day 21. Similarly, beta-actin mRNA, tested as a PCR control, persisted to day 21 in specimens held at ambient temperatures, but it was degraded in the remnants of tissues recovered from compost on day 21. Results from this study provide evidence that composting could be used for safe disposal of pig carcasses infected with FMD virus.
- Published
- 2010
44. Refuge or reservoir? The potential impacts of the biofuel crop Miscanthus x giganteus on a major pest of maize.
- Author
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Spencer JL and Raghu S
- Subjects
- Animals, Biomass, Female, Insecta growth & development, Life Cycle Stages, Male, Oviposition, Biofuels, Crops, Agricultural metabolism, Crosses, Genetic, Insecta physiology, Pest Control, Biological, Poaceae metabolism, Zea mays parasitology
- Abstract
Background: Interest in the cultivation of biomass crops like the C4 grass Miscanthus x giganteus (Miscanthus) is increasing as global demand for biofuel grows. In the US, Miscanthus is promoted as a crop well-suited to the Corn Belt where it could be cultivated on marginal land interposed with maize and soybean. Interactions (direct and indirect) of Miscanthus, maize, and the major Corn Belt pest of maize, the western corn rootworm, (Diabrotica virgifera virgifera LeConte, WCR) are unknown. Adding a perennial grass/biomass crop to this system is concerning since WCR is adapted to the continuous availability of its grass host, maize (Zea mays)., Methodology/principal Findings: In a greenhouse and field study, we investigated WCR development and oviposition on Miscanthus. The suitability of Miscanthus for WCR development varied across different WCR populations. Data trends indicate that WCR populations that express behavioural resistance to crop rotation performed as well on Miscanthus as on maize. Over the entire study, total adult WCR emergence from Miscanthus (212 WCR) was 29.6% of that from maize (717 WCR). Adult dry weight was 75-80% that of WCR from maize; female emergence patterns on Miscanthus were similar to females developing on maize. There was no difference in the mean no. of WCR eggs laid at the base of Miscanthus and maize in the field., Conclusions/significance: Field oviposition and significant WCR emergence from Miscanthus raises many questions about the nature of likely interactions between Miscanthus, maize and WCR and the potential for Miscanthus to act as a refuge or reservoir for Corn Belt WCR. Responsible consideration of the benefits and risks associated with Corn Belt Miscanthus are critical to protecting an agroecosystem that we depend on for food, feed, and increasingly, fuel. Implications for European agroecosystems in which Miscanthus is being proposed are also discussed in light of the WCR's recent invasion into Europe.
- Published
- 2009
- Full Text
- View/download PDF
45. Estrogen receptor alpha and beta specific agonists regulate expression of synaptic proteins in rat hippocampus.
- Author
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Waters EM, Mitterling K, Spencer JL, Mazid S, McEwen BS, and Milner TA
- Subjects
- Analysis of Variance, Animals, Estradiol analogs & derivatives, Estradiol pharmacology, Estrogen Receptor alpha metabolism, Estrogen Receptor beta metabolism, Estrogens pharmacology, Female, Hippocampus drug effects, Immunohistochemistry, Neurons drug effects, Neurons metabolism, Ovariectomy, Rats, Rats, Sprague-Dawley, Estrogen Receptor alpha agonists, Estrogen Receptor beta agonists, Hippocampus metabolism, Membrane Proteins metabolism, Nerve Tissue Proteins metabolism
- Abstract
Changes in hippocampal CA1 dendritic spine density and synaptic number across the estrous cycle in female rats correlate with increased hippocampal-dependent cognitive performance in a manner that is dependent on estrogen receptors (ERs). Two isoforms of the estrogen receptor, alpha and beta are present in the rat hippocampus and distinct effects on cognitive behavior have been described for each receptor. The present study generated a profile of synaptic proteins altered by administration of estradiol benzoate, the ERalpha selective agonist PPT (1,3,5-tris (4-hydroxyphenyl)-4-propyl-1H-pyrazole) and the ERbeta selective agonist DPN (2,3-bis (4-hydroxyphenyl) propionitrile) alone and in combination in comparison to vehicle in the CA1 region of the dorsal hippocampus. In the stratum radiatum, estradiol, DPN, and PPT increased PSD-95 and AMPA-type glutamate receptor subunit GluR1. Only DPN administration regulated expression of AMPA receptor subunits GluR2 and GluR3, increasing and decreasing levels respectively. DPN also increased GluR2 expression in the other lamina of the CA1. These results support previous reports that estradiol and isoform specific agonists differentially activate ERalpha and ERbeta to regulate protein expression. The distinct effects of DPN and PPT administration on synaptic proteins suggest that the desired therapeutic outcome of estrogen may be accomplished by using specific estrogen receptor agonists. Moreover, the effects of estradiol treatment on PSD-95 expression are consistent with a growing body of evidence that this postsynaptic protein is a key marker of estrogen action related to spine synapse formation.
- Published
- 2009
- Full Text
- View/download PDF
46. Synthesis and characterization of the dinuclear polyhydrides [Os(2)H(7)(PPh(i)Pr(2))(4)](+) and [Os(2)H(6)(PPh(i)Pr(2))(4)].
- Author
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Anderson BG, Hoyte SA, and Spencer JL
- Abstract
The dinuclear osmium polyhydride [Os(2)H(7)(PPh(i)Pr(2))(4)][HC(SO(2)CF(3))(2)] (1) was synthesized by the protonation of [OsH(6)(PPh(i)Pr(2))(2)] with bis(trifluoromethylsulfonyl)methane. Treatment with amine bases was not able to deprotonate 1, but reaction with potassium hydride gave the corresponding neutral polyhydride [Os(2)H(6)(PPh(i)Pr(2))(4)] (2). Single crystal X-ray diffraction revealed that 1 and 2 both crystallize in the P2(1)/c space group and are classical polyhydrides containing similar Os(mu-H)(3)Os cores with Os-Os distances of 2.5431(1) A and 2.5448(2) A, respectively. These structures represent rare examples of dinuclear osmium polyhydrides with six or more hydride ligands.
- Published
- 2009
- Full Text
- View/download PDF
47. Under-report and underdiagnosis of chronic respiratory diseases in an African country.
- Author
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Martins P, Rosado-Pinto J, do Céu Teixeira M, Neuparth N, Silva O, Tavares H, Spencer JL, Mascarenhas D, Papoila AL, Khaltaev N, and Annesi-Maesano I
- Subjects
- Adult, Asthma diagnosis, Asthma epidemiology, Bronchitis, Chronic diagnosis, Bronchitis, Chronic epidemiology, Cabo Verde epidemiology, Cross-Sectional Studies, Emphysema diagnosis, Emphysema epidemiology, Female, Forced Expiratory Volume, Humans, Male, Middle Aged, Prevalence, Risk Factors, Smoking adverse effects, Spirometry, Surveys and Questionnaires, Tuberculosis diagnosis, Tuberculosis epidemiology, Pulmonary Disease, Chronic Obstructive diagnosis, Pulmonary Disease, Chronic Obstructive epidemiology
- Abstract
Background: Chronic respiratory diseases (CRD) are greatly underestimated. The aim of this study was to assess the burden associated with reported CRD and chronic obstructive pulmonary disease, as defined on the basis of various standardized criteria, by estimating their point prevalence in a sample of individuals attending the Primary Health Care (PHC) level and Emergency Room (ER) Departments in Cape Verde (CV) archipelago. The second aim of the study was to identify factors related to airways obstruction and reported CRD in this population., Methods: A cross-sectional study was carried out in CV during 2 weeks. Outpatients aged more than 20 years seeking care at PHC level and ER answered a standardized questionnaire and were subjected to spirometry, independently of their complaint. Two criteria for airways obstruction were taken into account: forced expiratory volume (FEV(1)) <80% of the predicted value and FEV(1)/forced vital capacity (FVC) ratio <0.70., Results: A total of 274 individuals with a satisfactory spirometry were included. 22% of the individuals had a FEV(1) < 80%. Individuals older than 46 years had a higher risk of having airways obstruction. Asthma diagnosis (11%) had a clear association with airways obstruction. Smoking was a risk factor for a lower FEV(1). Working in a dust place and cooking using an open fire were both related to chronic bronchitis and asthma diagnosis., Conclusion: Under-report and underdiagnosis of chronic respiratory conditions seem to be a reality in CV just as in other parts of the world. To improve diagnosis, our results reinforce the need of performing a spirometry.
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- 2009
- Full Text
- View/download PDF
48. Survival of avian influenza and Newcastle disease viruses in compost and at ambient temperatures based on virus isolation and real-time reverse transcriptase PCR.
- Author
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Guan J, Chan M, Grenier C, Wilkie DC, Brooks BW, and Spencer JL
- Subjects
- Animal Feed, Animals, Chick Embryo, Feces virology, Hot Temperature, Soil Microbiology, Influenza A virus physiology, Newcastle disease virus physiology, Reverse Transcriptase Polymerase Chain Reaction, Soil analysis, Virus Inactivation
- Abstract
In four composting experiments, survival of avian influenza (AI) and Newcastle disease (ND) viruses was assessed by virus isolation in embryonated chicken eggs (ECEs) and by real-time reverse transcriptase-polymerase chain reaction. Specimens contained in nylon mesh bags consisted of 20-g samples of chicken manure, used litter, or feed that had been inoculated with allantoic fluid containing an AI virus (H6N2, Expt. 1) or an ND vaccine virus (Expt. 2). Other specimens consisted of 20-g samples of infected ECEs that had been homogenized and mixed with corn silage. As a control, allantoic fluid diluted in phosphate-buffered saline was contained in sealed vials. Except for the feed, in which the AI virus was inactivated soon after the specimen was inoculated, on day 0 the specimens buried in compost or placed outside at ambient temperatures contained at least 5.0 log10 of virus and 7.7 log10 of viral RNA. By day 7, temperatures in compost ranged from 50 C to 65 C, and viruses had been killed in all specimens in bags. In comparison, viruses in sealed vials remained viable to day 10. Viral RNA in mesh-bag specimens had been degraded to nondetectable levels by day 10, but it was still detected in sealed vials on day 21. In specimens that were held at ambient temperatures (13 C-28 C), the viruses in mesh-bag specimens were inactivated by day 21, but their RNA was still detected. In comparison, the viruses in sealed vials survived to day 21. In Expts. 3 and 4, viruses were inactivated in carcass specimens and in whole ECEs during composting. In an in vitro experiment, the time required for a 1-log10 reduction of viruses was significantly shorter (P < 0.05) in water extracts from compost than in phosphate buffers at temperatures of 25 C to 45 C. This study provided evidence that microbial activity during composting contributed to the rapid killing of AI and ND viruses and to the degradation of their viral RNA.
- Published
- 2009
- Full Text
- View/download PDF
49. Estrous cycle regulates activation of hippocampal Akt, LIM kinase, and neurotrophin receptors in C57BL/6 mice.
- Author
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Spencer JL, Waters EM, Milner TA, and McEwen BS
- Subjects
- Analysis of Variance, Animals, Behavior, Animal, Disks Large Homolog 4 Protein, Estradiol metabolism, Female, Gene Expression Regulation physiology, Guanylate Kinases, Hippocampus anatomy & histology, Intracellular Signaling Peptides and Proteins metabolism, Maze Learning drug effects, Membrane Proteins metabolism, Mice, Mice, Inbred C57BL, Progesterone metabolism, Synaptophysin metabolism, Estrous Cycle physiology, Hippocampus metabolism, Lim Kinases metabolism, Maze Learning physiology, Oncogene Protein v-akt metabolism, Receptors, Nerve Growth Factor metabolism
- Abstract
Estradiol modulates dendritic spine morphology and synaptic protein expression in the rodent hippocampus, as well as hippocampal-dependent learning and memory. In the rat, these effects may be mediated through nongenomic steroid signaling such as estradiol activation of the Akt and LIM kinase (LIMK) pathways, in addition to genomic signaling involving estradiol upregulation of brain-derived neurotrophic factor expression (BDNF). Due to the many species differences between mice and rats, including differences in the hippocampal response to estradiol, it is unclear whether estradiol modulates these pathways in the mouse hippocampus. Therefore, we investigated whether endogenous fluctuations of gonadal steroids modulate hippocampal activation of the Akt, LIMK, and the BDNF receptor TrkB in conjunction with spatial memory in female C57BL/6 mice. We found that Akt, LIMK, and TrkB were activated throughout the dorsal hippocampal formation during the high-estradiol phase, proestrus. Cycle phase also modulated expression of the pre- and post-synaptic markers synaptophysin and post-synaptic density 95. However, cycle phase did not influence performance on an object placement test of spatial memory, although this task is known to be sensitive to the complete absence of ovarian hormones. The findings suggest that endogenous estradiol and progesterone produced by the ovaries modulate specific signaling pathways governing actin remodeling, cell excitability, and synapse formation.
- Published
- 2008
- Full Text
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50. Development of methods for detection and quantification of avian influenza and Newcastle disease viruses in compost by real-time reverse transcription polymerase chain reaction and virus isolation.
- Author
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Guan J, Chan M, Ma B, Grenier C, Wilkie DC, Pasick J, Brooks BW, and Spencer JL
- Subjects
- Animals, Feces virology, Influenza A virus genetics, Manure virology, Newcastle disease virus genetics, RNA, Viral chemistry, RNA, Viral isolation & purification, Reverse Transcriptase Polymerase Chain Reaction methods, Soil analysis, Specific Pathogen-Free Organisms, Chickens, Influenza A virus isolation & purification, Newcastle disease virus isolation & purification, Reverse Transcriptase Polymerase Chain Reaction veterinary, Soil Microbiology
- Abstract
Composting has been used for disposal of poultry carcasses and manure following outbreaks caused by avian influenza virus (AIV) and Newcastle disease virus (NDV), but methods are needed to test for survival of the viruses in compost to ensure biosecurity. Methods developed in the present study include extracting viruses from compost and purifying viral RNA. The extracted viruses were detected by virus isolation using embryonated chicken eggs, and the purified RNA was detected by real-time reverse transcription PCR (RRT-PCR). The virus isolation and the RRT-PCR methods were evaluated with 3 compost preparations that were produced from chicken manure mixed with corn silage, wood shavings, or wheat straw. The detection limits of both methods were 1,700 and 1,000 embryo lethal doses of AIV and NDV per gram of compost, respectively. The copy number of viral RNA quantified by RRT-PCR was highly correlated with the amount of virus in compost. The results suggested that the RRT-PCR method may be used as an alternative to the virus isolation method for rapid detection and accurate quantification of AIV and NDV in compost.
- Published
- 2008
- Full Text
- View/download PDF
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