bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of DIVA vaccines and their companion diagnostic tests to foreign animal disease eradication
Authors: Pasick John 
Published: July 2005

AbstractThe risk of foreign animal disease introduction continues to exist despite Canada's strict regulations concerning the importation of animals and animal products. Given the rapidity with which these diseases can spread, especially in areas with dense livestock populations, eradication efforts which rely solely on quarantine and stamping-out measures can present a formidable undertaking. This, combined with growing economic and ethical considerations, has led to renewed interest in the use of vaccination as a tool in controlling foreign animal disease outbreaks. Vaccination has effects at the individual and population levels. Efficacious vaccines reduce or prevent clinical signs without necessarily preventing virus replication. They may also increase the dose of virus needed to establish an infection and/or reduce the level and duration of virus shedding following infection. Vaccine effectiveness within a population is a function of its ability to reduce virus transmission. Transmission is best described by the reproductive ratio, R, which is defined as the average number of new infections caused by one infectious individual. By helping to reduce the R-value below 1, vaccination can be an effective adjunct in abbreviating an outbreak. Nevertheless, vaccination can also complicate serological surveillance activities that follow eradication, if the antibody response induced by vaccination is indistinguishable from that which follows infection. This disadvantage can be overcome by the use of DIVA vaccines and their companion diagnostic tests. The term DIVA (differentiating infected from vaccinated individuals) was coined in 1999 by J. T. van Oirschot of the Central Veterinary Institute, in the Netherlands. It is now generally used as an acronym for ‘differentiating infected from vaccinated animals’. The term was originally applied to the use of marker vaccines, which are based on deletion mutants of wild-type microbes, in conjunction with a differentiating diagnostic test. The DIVA strategy has been extended to include subunit and killed whole-virus vaccines. This system makes possible the mass vaccination of a susceptible animal population without compromising the serological identification of convalescent individuals. The DIVA approach has been applied successfully to pseudorabies and avian influenza eradication, and has been proposed for use in foot-and-mouth disease and classical swine fever eradication campaigns. This paper will survey current vaccine technology, the host immune response, and companion diagnostic tests that are available for pseudorabies, foot-and-mouth disease, classical swine fever and avian influenza.
Cytotoxic T lymphocytes in protection against equine infectious anemia virus
Authors: McGuire Travis C. , Fraser Darrilyn G. , Mealey Robert H. 
Published: July 2005

AbstractCytotoxic T lymphocytes (CTL) are associated with virus control in horses infected with equine infectious anemia virus (EIAV). Early in infection, control of the initial viremia coincides with the appearance of CTL and occurs before the appearance of neutralizing antibody. In carrier horses, treatment with immunosuppressive drugs results in viremia before a change in serum neutralizing antibody occurs. Clearance of initial viremia caused by other lentiviruses, including human immunodeficiency virus-1 and simian immunodeficiency virus, is also associated with CTL and not neutralizing antibody. In addition, depletion of CD8+cells prior to infection of rhesus monkeys with simian immunodeficiency prevents clearance of virus and the same treatment of persistently infected monkeys results in viremia. Cats given adoptive transfers of lymphocytes from vaccinated cats were protected and the protection was MHC-restricted, occurred in the absence of antiviral humoral immunity, and correlated with the transfer of cells with feline immunodeficiency virus-specific CTL and T-helper lymphocyte activities. Therefore, a lentiviral vaccine, including one for EIAV, needs to induce CTL. Based on initial failures to induce CTL to EIAV proteins by any means other than infection, we attempted to define an experimental system for the evaluation of methods for CTL induction. CTL epitopes restricted by the ELA-A1 haplotype were identified and the MHC class I molecule presenting these peptides was identified. This was done by expressing individual MHC class I molecules from cDNA clones in target cells. The target cells were then pulsed with peptides and used with effector CTL stimulated with the same peptides. In a preliminary experiment, immunization of three ELA-A1 haplotype horses with an Env peptide restricted by this haplotype resulted in CTL in peripheral blood mononuclear cells (PBMC) which recognized the Env peptide and virus-infected cells, but the CTL response was transient. Nevertheless there was significant protection against clinical disease following EIAV challenge of these immunized horses when compared with three control horses given the same virus challenge. These data indicated that responses to peptides in immunized horses needed to be enhanced. Optimal CTL responses require help from CD4+T lymphocytes, and experiments were done to identify EIAV peptides which stimulated CD4+T lymphocytes in PBMC from infected horses with different MHC class II types. Two broadly cross-reactive Gag peptides were identified which stimulated only an interferon γ response by CD4+T lymphocytes, which indicated a T helper 1 response is needed for CTL stimulation. Such peptides should facilitate CTL responses; however, other problems in inducing protection against lentiviruses remain, the most significant of them being EIAV variants that can escape both CTL and neutralizing antibody. A possible solution to CTL escape variants is the induction of high-avidity CTL to multiple EIAV epitopes.
Efficacy and safety of a feline immunodeficiency virus vaccine
Authors: Huang Chengjin , Conlee Douglas , Loop Jennifer , Champ Deborah , Gill Mike , Chu Hsien-Jue (Steve) 
Published: July 2005

AbstractFel-O-Vax FIV is an inactivated virus vaccine designed as an aid in the prevention of infection of cats, 8 weeks or older, by feline immunodeficiency virus (FIV). It contains two genetically distinct FIV strains. The efficacy of this vaccine was demonstrated in a vaccination–challenge study designed to meet various regulatory requirements for registering the vaccine. Eight-week-old kittens were vaccinated with an immunogenicity vaccine which contained minimal release levels of FIV antigens formulated with a proprietary adjuvant system. Twelve months later, all vaccinates and controls were challenged with a heterologous FIV strain. Following the vigorous challenge exposure, cats were monitored for FIV viremia. It was found that 16% of the vaccinated cats developed viremia while 90% of the controls became persistently infected with FIV, which demonstrated that the vaccine was efficacious and the protective immunity lasted for at least 12 months. The safety of the vaccine was demonstrated by a field safety trial in which only 22 mild reactions of short duration were observed following administering 2051 doses of two pre-licensing serials of Fel-O-Vax FIV to cats of various breeds, ages and vaccination histories. Thus, Fel-O-Vax FIV is safe and efficacious for the prevention of FIV infection in cats.
Feline immunodeficiency virus diagnosis after vaccination
Authors: Andersen Philip R. , Tyrrell Phyllis 
Published: July 2005

AbstractPrior to the widespread use of vaccination for the control of feline immunodeficiency virus (FIV) infection, diagnosis was made by the detection of antibodies against FIV. A number of commercial animal side tests perform quite well for this determination, with positive predictive values between 91 and 100% and negative predictive values between 96 and 100%. Furthermore, results of these tests could be confirmed by western blot analysis of FIV test-positive sera. Currently, a killed whole virus FIV vaccine has been made available to practitioners. Vaccinated cats seroconvert by ELISA and western blot, making presently available diagnostic tests, which rely on antibody detection, useless in cats after vaccination. The advisory panels of the American Association of Feline Practitioners and Academy of Feline Medicine both recommend testing for feline leukemia virus antigen and FIV antibody before vaccination.
An overview of transmissible spongiform encephalopathies
Authors: Takemura K. , Kahdre M. , Joseph D. , Yousef A. , Sreevatsan S. 
Published: July 2005

AbstractTransmissible spongiform encephalopathies (TSEs) are fatal neurodegenerative disorders of humans and animals associated with an accumulation of abnormal isoforms of prion protein (PrP) in nerve cells. The pathogenesis of TSEs involves conformational conversions of normal cellular PrP (PrPc) to abnormal isoforms of PrP (PrPSc). While the protein-only hypothesis has been widely accepted as a causal mechanism of prion diseases, evidence from more recent research suggests a possible involvement of other cellular component(s) or as yet undefined infectious agent(s) in PrP pathogenesis. Although the underlying mechanisms of PrP strain variation and the determinants of interspecies transmissibility have not been fully elucidated, biochemical and molecular findings indicate that bovine spongiform encephalopathy in cattle and new-variant Creutzfeldt–Jakob disease in humans are caused by indistinguishable etiological agent(s). Cumulative evidence suggests that there may be risks of humans acquiring TSEs via a variety of exposures to infected material. The development of highly precise ligands is warranted to detect and differentiate strains, allelic variants and infectious isoforms of these PrPs. This article describes the general features of TSEs and PrP, the current understanding of their pathogenesis, recent advances in prion disease diagnostics, and PrP inactivation.
Can artificial sweeteners help control body weight and prevent obesity?
Authors: Benton David 
Published: July 2005

AbstractThe possible role played by artificial sweeteners in the long-term maintenance of body weight is considered. Although artificial sweeteners can play a role in a short-term energy-controlled diet, the evidence that they are helpful over a longer period is limited. In those in the recommended weight range there is evidence of compensation; that is, the consumption of low-energy foods is followed by an increased energy intake to make up the lost energy. Energy compensation is more likely in those not displaying dietary restraint. The desire to remove sugar from the diet reflects an assumption that its intake is associated with obesity. However, the consumption of energy-dense food, that almost entirely reflects a high fat and low water content, is the best predictor of obesity. Diets offering a high proportion of energy in the form of carbohydrate tend to contain low levels of fat. There are several reports that the use of artificial sweeteners leads to an increased consumption of fat. The weak ability of fat to satisfy hunger makes it easy to overeat fatty foods; in contrast, carbohydrates promote a feeling of ‘fullness’. Various short-term studies have found that carbohydrate consumed as a liquid, rather than a solid, is more likely to result in weight gain.
Paired immunoglobulin‐like receptors and their MHC class I recognition
Authors: Takai Toshiyuki 
Published: July 2005

SummaryThe immunoglobulin‐like receptors provide positive and negative regulation of immune cells upon recognition of various ligands, thus enabling those cells to respond properly to extrinsic stimuli. Murine paired immunoglobulin‐like receptor (PIR)‐A and PIR‐B, a typical receptor pair of the immunoglobulin‐like receptor family, are expressed on a wide range of cells in the immune system, such as B cells, mast cells, macrophages and dendritic cells, mostly in a pair‐wise fashion. The PIR‐A requires the homodimeric Fc receptor common γ chain for its efficient cell‐surface expression and for the delivery of an activation signal. In contrast, PIR‐B inhibits receptor‐mediated activation signals in vitro upon engagement with other activating‐type receptors, such as the antigen receptor on B cells and the high‐affinity Fc receptor for immunoglobulin E on mast cells. Recent identification of major histocompatibility complex (MHC) class I molecules as the physiological ligands for PIR has enabled us to attribute various immunological phenotypes observed in PIR‐B‐deficient mice to the consequences of the absence of a balanced interaction between PIR and MHC class I molecules expressed ubiquitously. Thus, PIR‐A and PIR‐B constitute a novel and physiologically important MHC class I recognition system.
Toll‐like receptors‐2, ‐3 and ‐4 expression patterns on human colon and their regulation by mucosal‐associated bacteria
Authors: Furrie Elizabeth , Macfarlane Sandra , Thomson George , Macfarlane George T. ,   Microbiology & Gut Biology Group, Tayside Tissue & Tumour Bank
Published: July 2005

SummaryThe colonic epithelium provides an interface between the host and micro‐organisms colonising the gastrointestinal tract. Molecular recognition of bacteria is facilitated through Toll‐like receptors (TLR). The colonic epithelium expresses relatively high levels of mRNA for TLR3 and less for TLR2 and ‐4. Little is known of the expression patterns and mode of induction of expression for these pattern recognition receptors in human colon. The aim of this study was to investigate their localization in the gut and induction of expression in epithelial cell lines by mucosal bacteria. TLR2 and ‐4 were expressed only in crypt epithelial cells, expression was lost as the cells matured and moved towards the gut lumen. In contrast, TLR3 was only produced in mature epithelial cells. HT29 and CACO‐2 had different levels of expression for TLR1–4. Co‐culture of HT29 cells with different mucosal isolates showed that they were highly responsive to bacterial challenge, with up‐regulation of mRNA for TLR1–4. In contrast, CACO‐2 cells were refractive to bacterial challenge, showing little difference in mRNA levels. TLR3 was induced in HT29 only by Gram‐positive commensals with up‐regulation of both mRNA and protein and an enhancement of the antiviral immune response. This pattern of expression allows induction of responsiveness to bacteria only by the crypt epithelium so that tolerance to commensal organisms can be maintained. In contrast, mature columnar epithelium is able to respond to viral pathogens, which are not part of the normal gut commensal microbiota.
Necrotizing activity of five Botrytis cinerea endopolygalacturonases produced in Pichia pastoris
Authors: Kars Ilona , Krooshof Geja H. , Wagemakers Lia , Joosten Rob , Benen Jacques A.E. , Van Kan Jan A.L. 
Published: July 2005

SummaryFive Botrytis cinerea endopolygalacturonase enzymes (BcPGs) were individually expressed in Pichia pastoris, purified to homogeneity and biochemically characterized. While the pH optima of the five enzymes were similar (approximately pH 4.5) the maximum activity of individual enzymes differed significantly. For hydrolysis of polygalacturonic acid (PGA), the Vmax,app ranged from 10 to 900 U mg−1, while the Km,app ranged from 0.16 to 0.6 mg ml−1. Although all BcPGs are true endopolygalacturonases, they apparently have different modes of action. PGA hydrolysis by BcPG1, BcPG2 and BcPG4 leads to the transient accumulation of oligomers with DP < 7, whereas PGA hydrolysis by BcPG3 and BcPG6 leads to the immediate accumulation of monomers and dimers. The necrotizing activity (NA) of all BcPGs was tested separately in tomato, broad bean and Arabidopsis thaliana. They showed different NAs on these plants. BcPG1 and BcPG2 possessed the strongest NA as tissue collapse was observed within 10 min after infiltration of broad bean leaves. The amino acid (aa) D192A substitution in the active site of BcPG2 not only abolished enzyme activity but also the NA, indicating that the NA is dependent on enzyme activity. Furthermore, deletion of the Bcpg2 gene in B. cinerea resulted in a strong reduction in virulence on tomato and broad bean. Primary lesion formation was delayed by approximately 24 h and the lesion expansion rate was reduced by 50–85%. These data indicate that BcPG2 is an important virulence factor for B. cinerea.
Virus‐induced gene silencing in tomato fruit
Authors: Fu Da‐Qi , Zhu Ben‐Zhong , Zhu Hong‐Liang , Jiang Wei‐Bo , Luo Yun‐Bo 
Published: July 2005

SummaryVirus‐induced gene silencing (VIGS) is a powerful tool for the study of gene function in plants. Here we report that either by syringe‐infiltrating the tobacco rattle virus (TRV)‐vector into the surface, stem or carpopodium of a tomato fruit attached to the plant or by vacuum‐infiltrating into a tomato fruit detached from the plant, TRV can efficiently spread and replicate in the tomato fruit. Although VIGS can be performed in tomato fruit by all of the means mentioned above, the most effective method is to inject the TRV‐vector into the carpopodium of young fruit attached to the plant about 10 days after pollination. Several reporter genes related to ethylene responses and fruit ripening, includingLeCTR1andLeEILsgenes, were also successfully silenced by this method during fruit development. In addition, we found that the silencing of theLeEIN2gene results in the suppression of tomato fruit ripening. The results of our study indicate that the application of VIGS techniques by the described methods can be successfully applied to tomato fruit and is a valuable tool for studying functions of the relevant genes during fruit developing.
ROSINA (RSI), a novel protein with DNA‐binding capacity, acts during floral organ development in Antirrhinum majus
Authors: Roccaro Mario , Li Yubin , Masiero Simona , Saedler Heinz , Sommer Hans 
Published: July 2005

SummaryPetal and stamen identity of the Antirrhinum majus flower is under the genetic control of the floral homeotic gene DEFICIENS (DEF). To isolate factors involved in the regulation of DEF gene activity, a promoter segment of this B‐function gene, containing cis‐acting regulatory elements, was used to identify the novel trans‐acting factor ROSINA (RSI). RSI does not show an extended similarity with any gene product present in the database. Rather RSI constitutes a protein that contains domains similar to known proteins from organisms of different phyla. The capacity of RSI to bind a sequence element of the DEF promoter, its spatial and temporal expression pattern together with the phenotype of RSI‐RNAi interference plants as well as RSI over‐expression in Arabidopsis thaliana suggest that RSI is a putative regulator of DEF gene activity in A. majus.
Confocal microscopy of whole ovules for analysis of reproductive development: the elongate1 mutant affects meiosis II
Authors: Barrell Philippa J. , Grossniklaus Ueli 
Published: July 2005

SummaryAnalysis of female meiosis (megasporogenesis) and embryo sac development (megagametogenesis) in angiosperms is technically challenging because the cells are enclosed within the nucellus and ovule tissues of the female flower. This is in contrast to male sporogenesis and gametogenesis where development can readily be observed through the easily dissectable developing anthers. Observation of embryo sac development is a particular problem in crassinucellate ovules such as those of maize. To overcome the problems in observing reproductive development, we developed a simple Feulgen staining procedure optimized for use with confocal microscopy to observe reproductive progression in the crassinucellate ovules of maize. The procedure greatly facilitates the observation of nuclei and cell structures of all stages of megasporogenesis and embryo sac development. The high resolution obtained using the technique enabled us to readily visualize chromosomes from individual cells within ovule tissue samples of maize. A propidium iodide staining technique was also used and compared with the Feulgen‐based technique. Static cytometry of relative DNA content of individual nuclei was possible using Imaris software on both Feulgen and propidium iodide‐stained samples. The techniques also proved successful for the observation of Arabidopsis and Hieracium aurantiacum female gametophyte and seed development, demonstrating the general applicability of the techniques. Using both staining methods, we analysed the maize meiotic mutant elongate1, which produces functional diploid instead of haploid embryo sacs. The precise defect in meiosis from which diploid embryo sacs arise in elongate1 has not previously been reported. We used confocal microscopy followed by static cytometry using Imaris software to show that the defect by which diploid embryo sacs arise in the maize mutant elongate1 is the absence of meiosis II with one of the dyad cells directly initiating megagametogenesis.
The role of abiotic conditions in shaping the long‐term patterns of a high‐elevation Argentine ant invasion
Authors: Krushelnycky Paul D. , Joe Stephanie M. , Medeiros Arthur C. , Daehler Curtis C. , Loope Lloyd L. 
Published: July 2005

ABSTRACTAnalysis of long‐term patterns of invasion can reveal the importance of abiotic factors in influencing invasion dynamics, and can help predict future patterns of spread. In the case of the invasive Argentine ant (Linepithema humile), most prior studies have investigated this species’ limitations in hot and dry climates. However, spatial and temporal patterns of spread involving two ant populations over the course of 30 years at a high elevation site in Hawaii suggest that cold and wet conditions have influenced both the ant's distribution and its rate of invasion. In Haleakala National Park on Maui, we found that a population invading at lower elevation is limited by increasing rainfall and presumably by associated decreasing temperatures. A second, higher elevation population has spread outward in all directions, but rates of spread in different directions appear to have been strongly influenced by differences in elevation and temperature. Patterns of foraging activity were strongly tied to soil temperatures, supporting the hypothesis that variation in temperature can influence rates of spread. Based on past patterns of spread, we predicted a total potential range that covers nearly 50% of the park and 75% of the park's subalpine habitats. We compared this rough estimate with point predictions derived from a degree‐day model for Argentine ant colony reproduction, and found that the two independent predictions match closely when soil temperatures are used in the model. The cold, wet conditions that have influenced Argentine ant invasion at this site are likely to be influential at other locations in this species’ current and future worldwide distribution.