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61.
Hayden KJ  Rizzo D  Tse J  Garbelotto M 《Phytopathology》2004,94(10):1075-1083
ABSTRACT The timely and accurate detection of pathogens is a critical aid in the study of the epidemiology and biology of plant diseases. In the case of regulated organisms, the availability of a sensitive and reliable assay is essential when trying to achieve early detection of the pathogen. We developed and tested a real-time, nested polymerase chain reaction (PCR) assay for the detection of Phytophthora ramorum, causal agent of sudden oak death. This technique then was implemented as part of a widespread environmental screen throughout California. The method here described is sensitive, detecting less than 12 fg of pathogen DNA, and is specific for P. ramorum when tested across 21 Phytophthora spp. Hundreds of symptomatic samples from 33 sites in 14 California counties were assayed, resulting in the discovery of 10 new host species and 23 infested areas, including 4 new counties. With the exception of a single host, PCR-based discovery of new hosts and infested areas always was confirmed by traditional pathogen isolations and inoculation studies. Nonetheless, molecular diagnostics were key in early pathogen detection, and steered the direction of further research on this newly discovered and generalist Phytophthora species.  相似文献   
62.
Organisms in the genus Anaplasma are obligate intracellular pathogens that multiply in both vertebrate and invertebrate hosts. The type species, Anaplasma marginale, causes bovine anaplasmosis and infects erythrocytes of the vertebrate host and undergoes a complex developmental cycle in ticks which serve as biological vectors. Infected cattle, wild ruminants and ticks can all serve as reservoirs of A. marginale. In this study, hunter killed Iberian red deer (Cervus elaphus hispanicus) from the region of Castilla-La Mancha in southwestern Spain were tested for Anaplasma infection. We found that 10% of the deer examined were seropositive for Anaplasma. Three A. marginale strains were subsequently obtained from salivary glands of Hyalomma marginatum that were removed from these deer, and the sequence of the major surface protein (msp)4 gene was determined for each strain and used for phylogenetic studies. Maximum parsimony analyses of msp4 sequences from H. marginatum ticks in comparison with New World cattle and bison isolates reported previously, suggested different origins for these Spanish A. marginale strains. The results of this study demonstrated that Iberian red deer are naturally infected with Anaplasma, and may therefore serve as a wildlife reservoir of the pathogen. Although the link between deer infection and the strains of A. marginale identified in ticks was not established, H. marginatum and Rhipicephalus bursa were identified as potential biological vectors for A. marginale in this region and may effect transmission of A. marginale between deer and cattle populations.  相似文献   
63.
OBJECTIVE: To determine whether there was an association between hypertensive retinopathy and high systolic, diastolic, and mean arterial blood pressures in cats. ANIMALS: 181 cats. PROCEDURE: Systolic, diastolic, and mean arterial blood pressures were measured by use of a noninvasive oscillometric technique. The range of blood pressure measurements in healthy cats from various age groups was determined. Associations among systolic, diastolic, and mean arterial blood pressure; hypertensive retinopathy; hyperthyroidism; left ventricular cardiac hypertrophy; chronic renal failure; and serum biochemical abnormalities were determined. RESULTS: All blood pressure measurements increased with age in healthy cats. The frequency of hypertensive retinopathy also increased with age and with blood pressure, and hypertensive retinopathy was particularly found in cats with systolic blood pressures > 168 mm Hg. There was an increased risk for hypertensive retinopathy in cats that were female, > 10 years old, and neutered. The risk of chronic renal failure also increased as blood pressure, particularly systolic blood pressure, increased. CONCLUSIONS AND CLINICAL RELEVANCE: Hypertensive retinopathy was common in cats > or = 10 years of age and was associated with systolic blood pressures > 168 mm Hg when measured by the noninvasive oscillometric technique.  相似文献   
64.
OBJECTIVE: To evaluate the long-term risks and benefits of early-age gonadectomy, compared with traditional-age gonadectomy, among dogs adopted from a large animal shelter. DESIGN: Retrospective cohort study. ANIMALS: 1,842 dogs. PROCEDURE: Dogs underwent gonadectomy and were adopted from an animal shelter before 1 year of age; follow-up was available for as long as 11 years after surgery. Adopters completed a questionnaire about their dogs' behavior and medical history. When possible, the dogs' veterinary records were reviewed. Associations between the occurrence of 56 medical and behavioral conditions and dogs' age at gonadectomy were evaluated. RESULTS: Among female dogs, early-age gonadectomy was associated with increased rate of cystitis and decreasing age at gonadectomy was associated with increased rate of urinary incontinence. Among male and female dogs with early-age gonadectomy, hip dysplasia, noise phobias, and sexual behaviors were increased, whereas obesity, separation anxiety, escaping behaviors, inappropriate elimination when frightened, and relinquishment for any reason were decreased. CONCLUSIONS AND CLINICAL RELEVANCE: Because early-age gonadectomy appears to offer more benefits than risks for male dogs, animal shelters can safely gonadectomize male dogs at a young age and veterinary practitioners should consider recommending routine gonadectomy for client-owned male dogs before the traditional age of 6 to 8 months. For female dogs, however, increased urinary incontinence suggests that delaying gonadectomy until at least 3 months of age may be beneficial.  相似文献   
65.
Major surface protein (MSP) 1a of the genus type species Anaplasma marginale (Rickettsiales: Anaplasmataceae) together with MSP1b forms the MSP1 complex. MSP1a has been shown to be involved in adhesion, infection and tick transmission of A. marginale, as well as to contribute to protective immunity in cattle. A differential antibody response to MSP1a and MSP1b was observed in cattle immunized with A. marginale derived from bovine erythrocytes (anti-MSP1a response) or cultured tick cells (anti-MSP1b response). In this study, we further characterized the MSP1a antibody response of cattle using several immunogens, including recombinant MSP1a (rMSP1a) protein, erythrocyte- or tick cell culture-derived A. marginale, or a combination of tick cell culture-derived A. marginale and rMSP1a. The MSP1a antibody response to all these immunogens was directed primarily against the N-terminal region of MSP1a that contains tandemly repeated peptides, whereas low antibody levels were detected against the C-terminal portion. Linear B-cell epitopes of MSP1a were mapped using synthetic peptides representing the entire sequence of the protein that were prepared by SPOT synthesis technology. Only two peptides in the N-terminal repeats were recognized by sera from immunized cattle. These peptides shared the sequence SSAGGQQQESS, which is likely to contain the linear B-cell epitope that was recognized by the pools of bovine sera. The average differential of antibody titers against MSP1a minus those against MSP1b correlated with lower percent reductions in PCV. A preferential antibody response to MSP1a was observed in cattle immunized with erythrocyte-derived, cell culture-derived plus rMSP1a or rMSP1a alone, and the percent reduction PCV was significantly lower in these cattle as compared with the other immunization groups. These results provide insight into the bovine antibody response against A. marginale and the role of MSP1a in protection of cattle against A. marginale infection.  相似文献   
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68.
Cardio-facio-cutaneous (CFC) syndrome is a sporadic developmental disorder involving characteristic craniofacial features, cardiac defects, ectodermal abnormalities, and developmental delay. We demonstrate that heterogeneous de novo missense mutations in three genes within the mitogen-activated protein kinase (MAPK) pathway cause CFC syndrome. The majority of cases (18 out of 23) are caused by mutations in BRAF, a gene frequently mutated in cancer. Of the 11 mutations identified, two result in amino acid substitutions that occur in tumors, but most are unique and suggest previously unknown mechanisms of B-Raf activation. Furthermore, three of five individuals without BRAF mutations had missense mutations in either MEK1 or MEK2, downstream effectors of B-Raf. Our findings highlight the involvement of the MAPK pathway in human development and will provide a molecular diagnosis of CFC syndrome.  相似文献   
69.
Fishing, trophic cascades, and the process of grazing on coral reefs   总被引:1,自引:0,他引:1  
Since the mass mortality of the urchin Diadema antillarum in 1983, parrotfishes have become the dominant grazer on Caribbean reefs. The grazing capacity of these fishes could be impaired if marine reserves achieve their long-term goal of restoring large consumers, several of which prey on parrotfishes. Here we compare the negative impacts of enhanced predation with the positive impacts of reduced fishing mortality on parrotfishes inside reserves. Because large-bodied parrotfishes escape the risk of predation from a large piscivore (the Nassau grouper), the predation effect reduced grazing by only 4 to 8%. This impact was overwhelmed by the increase in density of large parrotfishes, resulting in a net doubling of grazing. Increased grazing caused a fourfold reduction in the cover of macroalgae, which, because they are the principal competitors of corals, highlights the potential importance of reserves for coral reef resilience.  相似文献   
70.
A high mortality outbreak of respiratory mycoplasmosis occurred in goats in Mexico. The clinicopathologic presentation resembled contagious caprine pleuropneumonia caused by Mycoplasma capricolum subspecies capripneumoniae. By using a battery of polymerase chain reaction assays, the mycoplasma associated with this outbreak was identified as Mycoplasma mycoides subsp. capri.  相似文献   
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