Generic indicators for loss of resilience before a tipping point leading to population collapse     

Dai L  Vorselen D  Korolev KS  Gore J 《Science (New York, N.Y.)》2012,336(6085):1175-1177

Theory predicts that the approach of catastrophic thresholds in natural systems (e.g., ecosystems, the climate) may result in an increasingly slow recovery from small perturbations, a phenomenon called critical slowing down. We used replicate laboratory populations of the budding yeast Saccharomyces cerevisiae for direct observation of critical slowing down before population collapse. We mapped the bifurcation diagram experimentally and found that the populations became more vulnerable to disturbance closer to the tipping point. Fluctuations of population density increased in size and duration near the tipping point, in agreement with the theory. Our results suggest that indicators of critical slowing down can provide advance warning of catastrophic thresholds and loss of resilience in a variety of dynamical systems.  相似文献   

Paternal and maternal effects on the response of seed germination to high temperatures in Eucalyptus globulus     

Kieren D. Rix  Alistair J. Gracie  Bradley M. Potts  Phillip H. Brown  Cameron J. Spurr  Peter L. Gore 《Annals of Forest Science》2012,69(6):673-679

Context

High temperature stress in nurseries germinating Eucalyptus globulus seed is an important problem affecting germination synchrony and rate. Where there is a risk of high-temperature stress, then the choice of female parent may be important. This issue is particularly relevant to the production of full-sib families from mass-supplementary pollination where there may be opportunities for seed producers to manipulate the directionality of the crossing done in seed orchards.

Aims

This study aimed to quantify the maternal versus paternal influence of seed sensitivity to high temperature stress during germination.

Methods

A diallel crossing scheme involving four genotypes was used to test the relative importance of male and female genetic influences on the germination and development of E. globulus seed and their response to high temperature stress. Seed was germinated at optimum (25°C) and supra-optimal (32°C and 37°C) temperatures, and six traits describing the proportion and rate of seed germination and early seedling development were assessed.

Results

Both paternal and maternal effects affected the germination response, arguing for at least some influence of the nuclear genotype of the embryo. However, the response to high temperature stress was more influenced by the maternal than paternal parent.

Conclusion

Both the male and female genotype may affect various aspects of seed germination and early seedling development independent of seed size; however, some facets of the germination response will be mainly affected by the female parent.  相似文献   

Amphibian emergency medicine.     

Leigh Ann Clayton  Stacey R Gore 《Veterinary Clinics of North America: Exotic Animal Practice》2007,10(2):587-620

General concepts of amphibian emergency medicine are presented, including a review of patient selection, appropriate history, and helpful equipment. Physical examination procedures, general treatment, and diagnostic techniques are discussed. This is followed by a review of conditions commonly observed in amphibians and specific treatment options.  相似文献   

Metabolic adaptations associated with irreversible glucose loss are different to those observed during under-nutrition     

Meier S  Gore PJ  Barnett CM  Cursons RT  Phipps DE  Watkins KA  Verkerk GA 《Domestic animal endocrinology》2008,34(3):269-277

In this study the hypothesis that irreversible glucose loss results in an 'uncoupling' of the somatotrophic axis (increasing plasma GH levels and decreasing plasma IGF-I) was tested. During periods of negative energy balance the somatotrophic axis respond by increasing plasma GH and decreasing plasma IGF-I levels. In turn, elevated GH repartitions nutrient by increasing lipolysis and protein synthesis, and decreases protein degradation. Irreversible glucose loss was induced using sub-cutaneous injections of phloridizin. Seven non-lactating cows were treated with 8g/day phloridizin (PHZ) and seven control animals (CTRL, 0g/day), while being restricted to a diet of 80% maintenance. PHZ treatment increased urinary glucose excretion (P<0.001), resulting in hypoglycemia (P<0.001). As a response to this glucose loss, the PHZ treated animals had elevated plasma NEFA (P<0.005) and BHBA (P<0.001) levels. Average plasma insulin concentrations were not altered with PHZ treatment (P=0.059). Plasma GH was not different between the two groups (P>0.1), whereas plasma IGF-I levels decreased significantly (P<0.001) with PHZ treatment. The decline in plasma IGF-I concentrations was mirrored by a decrease in the abundance of hepatic IGF-I mRNA (P=0.005), in addition the abundance of hepatic mRNA for both growth hormone receptors (GHR(tot) and GHR(1A)) was also decreased (P<0.05). Therefore, the irreversible glucose loss resulted in a partial 'uncoupling' of the somatotrophic axis, as no increase in plasma GH levels occurred although plasma IGF-I levels, hepatic IGF-I mRNA declined, and the abundance of liver GH receptor mRNA declined.  相似文献   

Experimental infection of pregnant goats with bovine viral diarrhea virus (BVDV) 1 or 2     

Thomas Passler  Kay P Riddell  Misty A Edmondson  Manuel F Chamorro  John D Neill  Bruce W Brodersen  Heather L Walz  Patricia K Galik  Yijing Zhang  Paul H Walz 《Veterinary research》2014,45(1):38

Infections with bovine viral diarrhea virus (BVDV) of the genus pestivirus, family Flaviviridae, are not limited to cattle but occur in various artiodactyls. Persistently infected (PI) cattle are the main source of BVDV. Persistent infections also occur in heterologous hosts such as sheep and deer. BVDV infections of goats commonly result in reproductive disease, but viable PI goats are rare. Using 2 BVDV isolates, previously demonstrated to cause PI cattle and white-tailed deer, this study evaluated the outcome of experimental infection of pregnant goats. Pregnant goats (5 goats/group) were intranasally inoculated with BVDV 1b AU526 (group 1) or BVDV 2 PA131 (group 2) at approximately 25–35 days of gestation. The outcome of infection varied considerably between groups. In group 1, only 3 does became viremic, and 1 doe gave birth to a stillborn fetus and a viable PI kid, which appeared healthy and shed BVDV continuously. In group 2, all does became viremic, 4/5 does aborted, and 1 doe gave birth to a non-viable PI kid. Immunohistochemistry demonstrated BVDV antigen in tissues of evaluated fetuses, with similar distribution but reduced intensity as compared to cattle. The genetic sequence of inoculated viruses was compared to those from PI kids and their dam. Most nucleotide changes in group 1 were present during the dam’s acute infection. In group 2, a similar number of mutations resulted from fetal infection as from maternal acute infection. Results demonstrated that BVDV may cause reproductive disease but may also be maintained in goats.  相似文献   

EGFR activation mediates inhibition of axon regeneration by myelin and chondroitin sulfate proteoglycans     

Koprivica V  Cho KS  Park JB  Yiu G  Atwal J  Gore B  Kim JA  Lin E  Tessier-Lavigne M  Chen DF  He Z 《Science (New York, N.Y.)》2005,310(5745):106-110

Inhibitory molecules associated with myelin and the glial scar limit axon regeneration in the adult central nervous system (CNS), but the underlying signaling mechanisms of regeneration inhibition are not fully understood. Here, we show that suppressing the kinase function of the epidermal growth factor receptor (EGFR) blocks the activities of both myelin inhibitors and chondroitin sulfate proteoglycans in inhibiting neurite outgrowth. In addition, regeneration inhibitors trigger the phosphorylation of EGFR in a calcium-dependent manner. Local administration of EGFR inhibitors promotes significant regeneration of injured optic nerve fibers, pointing to a promising therapeutic avenue for enhancing axon regeneration after CNS injury.  相似文献   

Angioinvasive lymphoma (lymphomatoid granulomatosis) in a cat,with cutaneous and ocular metastasis     

Rebecca Bacon  Vinay Shivanna  Misty Gore  Jamie Henningson  Charan Ganta 《Journal of veterinary diagnostic investigation》2021,33(2):340

Lymphomatoid granulomatosis (LYG) is a rare variant of an angioinvasive T-cell lymphoproliferative disorder that primarily affects the lungs, with common sites of metastasis including the skin and subcutis. In humans, it is a B-cell lymphoproliferative disorder associated with Epstein-Barr virus infection. Our case is a 7-y-old, spayed female, domestic longhair cat that decompensated and was euthanized following an initial diagnosis of angioinvasive lymphoma from a skin biopsy. Autopsy revealed nodules in the lungs and subcutis, and corneal thickening and cloudiness. Histologic examination of cutaneous nodules, lungs, and eye showed similar angioinvasive cellular infiltrates and pattern to that of the original skin biopsy, consistent with a diagnosis of LYG. The neoplastic cells displayed CD3-positive immunoreactivity in the skin, eye, and lung, and PCR for antigen receptor rearrangement (PARR) showed T-cell clonality in all tissues tested. This is the third case of LYG to be reported in cats and is the only case in which PARR analysis and immunophenotyping immunohistochemical staining was performed. LYG with ocular involvement has not been reported previously in cats, to our knowledge. Our case demonstrates the necessity for considering LYG when presented with a cat with respiratory signs in conjunction with subcutaneous nodules and ocular lesions.  相似文献   

Retraction     

Case RB  Chang YP  Smith SB  Gore J  Cozzarelli NR  Bustamante C 《Science (New York, N.Y.)》2005,307(5714):1409

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Three-year duration of immunity in cats following vaccination against feline rhinotracheitis virus, feline calicivirus, and feline panleukopenia virus     

Gore TC  Lakshmanan N  Williams JR  Jirjis FF  Chester ST  Duncan KL  Coyne MJ  Lum MA  Sterner FJ 《Veterinary therapeutics : research in applied veterinary medicine》2006,7(3):213-222

Forty-two seronegative cats received an initial vaccination at 8 weeks of age and a booster vaccination at 12 weeks. All cats were kept in strict isolation for 3 years after the second vaccination and then were challenged with feline calicivirus (FCV) or sequentially challenged with feline rhinotracheitis virus (FRV) followed by feline panleukopenia virus (FPV). For each viral challenge, a separate group of 10 age-matched, nonvaccinated control cats was also challenged. Vaccinated cats showed a statistically significant reduction in virulent FRV-associated clinical signs (P = .015), 100% protection against oral ulcerations associated with FCV infection (P < .001), and 100% protection against disease associated with virulent FPV challenge (P < .005). These results demonstrated that the vaccine provided protection against virulent FRV, FCV, and FPV challenge in cats 8 weeks of age or older for a minimum of 3 years following second vaccination.  相似文献   

Natural Colonization of Rice by Arbuscular Mycorrhizal Fungi in Different Production Areas   总被引：1，自引：0，他引：1  

Lina Bernaola  Grace Cange  Michael O. Way  Jeffrey Gore  Jarrod Hardke  Michael Stout 《水稻科学》2018,25(3):169-174

Interactions between plants and soil microorganisms can influence the other interactions in which plants participate, including interactions with herbivores. Many fungi, including arbuscular mycorrhizal fungi(AMF), form symbiotic relationships with the roots they inhabit, and potentially alter defense against pests. The objective of this study was to document the extent of root colonization by AMF on non-flooded rice plants grown under conditions typical of commercial fields. We hypothesized that AMF naturally colonized rice plants in different rice producing field locations. Rice plant samples were collected from areas across the southern United States, including Texas, Mississippi, Arkansas and two research stations in Louisiana. We quantified the amount of AMF colonization in insecticide-free rice plants over three consecutive years(2014–2016). The results revealed natural colonization of AMF in all rice producing areas. In all the three years of survey, rice-AMF associations were the greatest in Arkansas followed by Mississippi and Texas. This research will help draw attention to natural colonization of AMF in rice producing areas that can impact future rice research and production by facilitating agricultural exploitation of the symbiosis.  相似文献