The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
James P Collins - One of the best experts on this subject based on the ideXlab platform.
-
mortality rates differ among amphibian populations exposed to three strains of a lethal ranavirus
Ecohealth, 2009Co-Authors: Trent K Bollinger, Danna M. Schock, James P CollinsAbstract:Infectious diseases are a growing threat to biodiversity, in many cases because of synergistic effects with habitat loss, environmental contamination, and climate change. Emergence of pathogens as new threats to host populations can also arise when novel combinations of hosts and pathogens are unintentionally brought together, for example, via commercial trade or wildlife relocations and reintroductions. Chytrid fungus (Batrachochytrium dendrobatidis) and amphibian ranaviruses (family Iridoviridae) are pathogens implicated in global amphibian declines. The emergence of disease associated with these pathogens appears to be at least partly related to recent translocations over large geographic distances. We experimentally examined the outcomes of novel combinations of host populations and pathogen strains using the amphibian ranavirus Ambystoma tigrinum virus (ATV) and barred tiger salamanders (Ambystoma mavortium, formerly considered part of the Ambystoma tigrinum complex). One salamander population was highly resistant to lethal infections by all ATV strains, including its own strain, and mortality rates differed among ATV strains according to salamander population. Mortality rates in novel pairings of salamander population and ATV strain were not predictable based on knowledge of mortality rates when salamander populations were exposed to their own ATV strain. The underlying cause(s) for the differences in mortality rates are unknown, but local selection pressures on salamanders, viruses, or both, across the range of this widespread host–pathogen system are a plausible hypothesis. Our study highlights the need to minimize translocations of amphibian ranaviruses, even among conspecifc host populations, and the importance of considering intraspecific variation in endeavors to manage wildlife diseases.
-
spatial and temporal patterns of Ambystoma tigrinum virus atv prevalence in tiger salamanders Ambystoma tigrinum nebulosum
Diseases of Aquatic Organisms, 2009Co-Authors: Jesse L. Brunner, Amy L. Greer, James P CollinsAbstract:Amphibian ranaviruses have been documented as causes of mass mortality in amphib- ian populations throughout the world. The temporal and spatial dynamics of ranavirus infections when epidemics are not apparent remains unclear. To address this question, we collected tissue sam- ples from 2003 to 2006 in 4 geographically separated tiger salamander Ambystoma tigrinum nebulo- sum host populations on the Kaibab Plateau in northern Arizona. We tested for Ambystoma tigrinum virus (ATV), a lethal ranavirus of tiger salamanders, calculated ATV prevalence for each sampling date, and examined temporal and spatial patterns by quantifying the annual level of ATV synchrony among populations using the intraclass correlation coefficient. Salamander populations were com- monly infected with ATV. We observed no morbidity or mortality in these populations even as ATV prevalence values varied from 0 to 57%. Infection prevalence across the landscape was more similar within a given year than between years. There was no statistically significant spatial pattern in preva- lence across the landscape. Our findings highlight the need to explore new hypotheses regarding the population level impact of these pathogens on amphibian communities.
-
Transmission dynamics of the amphibian ranavirus Ambystoma tigrinum virus.
Diseases of aquatic organisms, 2007Co-Authors: Jesse L. Brunner, Danna M. Schock, James P CollinsAbstract:Transmission is central to pathogen fitness and strongly influences the impact of pathogens on host populations. Particularly important to transmission dynamics is the distinction between direct transmission requiring close physical contact (e.g. bumping, fighting, or coughing) and indirect transmission from environmental sources such as contaminated substrates. We present data from 4 experiments addressing the form, routes, and timing of transmission of Ambystoma tigrinum virus (ATV) among tiger salamanders Ambystoma tigrinum nebulosum. Our data suggest that ATV is efficiently transmitted by direct interactions between live animals (bumping, biting and cannibalism) as well as by necrophagy and indirectly via water and fomites. Determining which form of transmission is most important in nature is essential for understanding transmission at the population level. Our experiments also revealed an important temporal aspect of infectiousness: larval salamanders become infectious soon after exposure to ATV and their propensity to infect others increases with time. These results begin to clarify the mechanisms and dynamics of ATV transmission and lead to key questions that need to be addressed in future research.
-
sensitivity of a diagnostic test for amphibian ranavirus varies with sampling protocol
Journal of Wildlife Diseases, 2007Co-Authors: Amy L. Greer, James P CollinsAbstract:Field samples are commonly used to estimate disease prevalence in wild populations. Our confidence in these estimates requires understanding the sensitivity and specificity of the diagnostic tests. We assessed the sensitivity of the most commonly used diagnostic tests for amphibian Ranavirus by infecting salamanders (Ambystoma tigrinum; Amphibia, Caudata) with Ambystoma tigrinum virus (ATV) and then sampling euthanized animals (whole animal) and noneuthanized animals (tail clip) at five time intervals after exposure. We used a standard polymerase chain reaction (PCR) protocol to screen for ATV. Agreement between test results from whole-animal and tail-clip samples increased with time postexposure. This indicates that the ability to identify infected animals increases following exposure, leading to a more accurate estimate of prevalence in a population. Our results indicate that tail-clip sampling can underestimate the true prevalence of ATV in wild amphibian populations.
-
Susceptibility of the Endangered California Tiger Salamander, Ambystoma californiense, to Ranavirus Infection
Journal of wildlife diseases, 2007Co-Authors: Angela M. Picco, Jesse L. Brunner, James P CollinsAbstract:Emerging infectious diseases are implicated in the declines and extinctions of amphibians worldwide. Ranaviruses in the family Iridoviridae are a global concern and have caused amphibian die-offs in wild populations in North America, Europe, South America, and in commercial populations in Asia and South America. The movement of amphibians for bait, food, pets, and research provides a route for the introduction of ranaviruses into naive and potentially endangered species. In this report, we demonstrate that the California tiger salamander, Ambystoma californiense, is susceptible to Ambystoma tigrinum virus (ATV). This virus has not been previously reported in California tiger salamander, but observed mortality in experimentally infected animals suggests that California tiger salamander populations could be adversely affected by an ATV introduction.
Gerard Strecker - One of the best experts on this subject based on the ideXlab platform.
-
structure of six 3 deoxy d glycero d galacto nonulosonic acid kdn containing oligosaccharide alditols released from oviduct secretions of Ambystoma maculatum characterization of the sequence fucosyl alpha 1 2 fucosyl alpha 1 3 fucosyl alpha 1 4 3 deo
FEBS Journal, 1995Co-Authors: Mariedominique Fontaine, Jeanmichel Wieruszeski, Yves Plancke, Florence Delplace, Gerard StreckerAbstract:: The O-linked acidic oligosaccharides of the jelly coat surrounding the eggs of Ambystoma maculatum were analyzed by NMR spectroscopy. The structures of the major oligosaccharides were established as follows where Kdn represents 3-deoxy-D-glycero-D-galacto-nonulsonic acid and GalNAc-ol is N-acetylgalactosaminitol: [sequence: see text] As shown for five other amphibian species, the structures of these carbohydrate chains appear to be species specific and can afford a basis for molecular taxonomy. These new sequences also reflect the occurrence of specific fucosyltransferase activities that are characteristic of Ambystoma maculatum.
-
structure of six 3 deoxy d glycero d galacto nonulosonic acid kdn containing oligosaccharide alditols released from oviduct secretions of Ambystoma maculatum
FEBS Journal, 1995Co-Authors: Mariedominique Fontaine, Jeanmichel Wieruszeski, Yves Plancke, Florence Delplace, Gerard StreckerAbstract:TheO-linked acidic oligosaccharides of the jelly coat surrounding the eggs of Ambystoma maculatum were analyzed by NMR spectroscopy. The structures of the major oligosaccharides were established as follows where Kdn represents 3-deoxy-d-glycero-d-galacto-nonulosonic acid and GalNAc-ol is N-acetylgalactosaminitol: As shown for five other amphibian species, the structures of these carbohydrate chains appear to be species specific and can afford a basis for molecular taxonomy. These new sequences also reflect the occurrence of specific fucosyltransferase activities that are characteristic of Ambystoma maculatum.
-
primary structure of acidic oligosaccharide alditols derived from the jelly coat of Ambystoma tigrinum
FEBS Journal, 1995Co-Authors: Emmanuel Maes, Yves Plancke, Florence Delplace, Gerard StreckerAbstract:Eleven O-glycosidic carbohydrate units derived from the jelly coat of Ambystoma tigrinum were analyzed by 1H-NMR spectroscopy. As previously shown for four other amphibian species, the glycans display a remarkable species specificity. As a characteristic feature, 3-deoxy-d-glycero -d-galacto -nonulo-sonic acid (Kdn) was found difucosylated at C4 and C5, and α-Gal attached to C3 of GalNAc-ol. The most representative carbohydrate units are:
-
structure of three kdn containing oligosaccharide alditols released from oviducal secretions of Ambystoma tigrinum characterization of the carbohydrate sequence fuc α1 5 fuc α1 4 kdn α2 3 6
FEBS Letters, 1995Co-Authors: Emmanuel Maes, Jeanmichel Wieruszeski, Yves Plancke, Gerard StreckerAbstract:Oligosaccharide-alditols released by reductive β-elimination from the egg jelly coat of Ambystoma tigrinum were analyzed by 1H NMR spectroscopy. As observed for five other amphibian species, these carbohydrate chains are highly species-specific, and should support the species-specificity of gamete interaction. The carbohydrate chains of Ambystoma tigrinum are characterized by the presence of a new type of sequence: Fuc (α1–5) [(Fuc (α1–4)] Kdn (α2–3/6).
Andrew Storfer - One of the best experts on this subject based on the ideXlab platform.
-
transcriptional response of mexican axolotls to Ambystoma tigrinum virus atv infection
BMC Genomics, 2008Co-Authors: Jennifer D Cotter, Andrew Storfer, Robert B Page, Christopher K Beachy, Randal S VossAbstract:Background Very little is known about the immunological responses of amphibians to pathogens that are causing global population declines. We used a custom microarray gene chip to characterize gene expression responses of axolotls (Ambystoma mexicanum) to an emerging viral pathogen, Ambystoma tigrinum virus (ATV).
-
effects of atrazine and iridovirus infection on survival and life history traits of the long toed salamander Ambystoma macrodactylum
Environmental Toxicology and Chemistry, 2006Co-Authors: Diane Denise Forson, Andrew StorferAbstract:Environmental contaminants and emerging infectious diseases are implicated as factors contributing to global amphibian declines. However, few studies have tested the interaction of these factors. We exposed six-week-old, larval long-toed salamanders (Ambystoma macrodactylum) to Ambystoma tigrinum virus (ATV; 0 or 10(3.5) plaque-forming units/ml) and sublethal concentrations of atrazine (0, 1.84, 18.4, and 184 microg/L) in a 4 x 2 factorial design for 30 d. We tested the effects of atrazine and virus on mass and snout-vent length (SVL) at metamorphosis and larval period as well as on rates of mortality and viral infectivity. We confirmed ATV transmission to A. macrodactylum via polymerase chain reaction, but infection rates were lower than expected, consistent with the theory predicting lower pathogen transmission to nonnative hosts. Larvae exposed to both atrazine and ATV had lower levels of mortality and ATV infectivity compared to larvae exposed to virus alone, suggesting atrazine may compromise virus efficacy. The highest atrazine level (184 microg/L) accelerated metamorphosis and reduced mass and SVL at metamorphosis significantly relative to controls. Exposure to ATV also significantly reduced SVL at metamorphosis. The present study suggests moderate concentrations of atrazine may ameliorate effects of ATV on long-toed salamanders, whereas higher concentrations initiate metamorphosis at a smaller size, with potential negative consequences to fitness.
Randal S Voss - One of the best experts on this subject based on the ideXlab platform.
-
transcriptional response of mexican axolotls to Ambystoma tigrinum virus atv infection
BMC Genomics, 2008Co-Authors: Jennifer D Cotter, Andrew Storfer, Robert B Page, Christopher K Beachy, Randal S VossAbstract:Background Very little is known about the immunological responses of amphibians to pathogens that are causing global population declines. We used a custom microarray gene chip to characterize gene expression responses of axolotls (Ambystoma mexicanum) to an emerging viral pathogen, Ambystoma tigrinum virus (ATV).
Bertram L Jacobs - One of the best experts on this subject based on the ideXlab platform.
-
Characterization of a PKR inhibitor from the pathogenic ranavirus, Ambystoma tigrinum virus, using a heterologous vaccinia virus system.
Virology, 2017Co-Authors: Trung Huynh, James K Jancovich, Latha Tripuraneni, Michael C. Heck, Jeffrey Langland, Bertram L JacobsAbstract:Ambystoma tigrinum virus (ATV) (family Iridoviridae, genus Ranavirus) was isolated from diseased tiger salamanders (Ambystoma tigrinum stebbinsi) from the San Rafael Valley in southern Arizona, USA in 1996. Genomic sequencing of ATV, as well as other members of the genus, identified an open reading frame that has homology to the eukaryotic translation initiation factor, eIF2α (ATV eIF2α homologue, vIF2αH). Therefore, we asked if the ATV vIF2αH could also inhibit PKR. To test this hypothesis, the ATV vIF2αH was cloned into vaccinia virus (VACV) in place of the well-characterized VACV PKR inhibitor, E3L. Recombinant VACV expressing ATV vIF2αH partially rescued deletion of the VACV E3L gene. Rescue coincided with rapid degradation of PKR in infected cells. These data suggest that the salamander virus, ATV, contains a novel gene that may counteract host defenses, and this gene product may be involved in the presentation of disease caused by this environmentally important pathogen.
-
Transmission of the Ambystoma tigrinum virus to alternative hosts.
Diseases of aquatic organisms, 2001Co-Authors: James K Jancovich, Elizabeth W. Davidson, Bertram L Jacobs, April Seiler, James P CollinsAbstract:Ambystoma tigrinum virus (ATV) is a lethal virus originally isolated from Sonora tiger salamanders Ambystoma tigrinum stebbinsi in the San Rafael Valley in southern Arizona. USA. ATV is implicated in several salamander epizootics. We attempted to transmit ATV experimentally to fish and amphibians by injection, water bath exposure, or feeding to test whether ATV can cause clinical signs of infection or be recovered from exposed individuals that do not show clinical signs. Cell culture and polymerase chain reaction of the viral major capsid protein gene were used for viral detection. Salamanders and newts became infected with ATV and the virus was recovered from these animals, but virus could not be recovered from any of the frogs or fish tested. These results suggest that ATV may only infect urodeles and that fish and frogs may not be susceptible to ATV infection.
-
isolation of a lethal virus from the endangered tiger salamander Ambystoma tigrinum stebbinsi
Diseases of Aquatic Organisms, 1997Co-Authors: James K Jancovich, Elizabeth W. Davidson, Frank J Morado, Bertram L Jacobs, James P CollinsAbstract:The Sonora tlger salamander Ambystoma tignnuni stebb~nsi Lowe is a genetically d~stinct race restricted to about 30 small ponds in the San Rafael Valley 111 southern Arizona, USA, which was added recently to the USA Federal List of Endangered Species Populations of these salamanders periodically expenence decimating epizootics. Virus was ~solated from diseased salamanders using fish cell cultures, injected into healthy laboratory-reared salamanders, and then reisolated in cell culture. Electron microscopy of thin sections from dying salamanders revealed abundant enveloped and nonenveloped icosahedral virus particles approximately 160 to 180 nm in diameter in the cytoplasm of skin and liver cells and free in the intercellular spaces. This virus, believed to be an iridovirus based on viral morphology and host pathology, was demonstrated to be the primary pathogen in these epizootics, and is the first lethal epizootic virus reported from salamanders. We have named the virus Ambystoma tigrinum Virus (ATV). Hemolytic bacteria were isolated from sick individuals, but we were unable to induce the disease by exposing salamanders to isolated bacteria at concentrations up to 10' ml-'