Recovery of Salmonella from shell eggs.   总被引：1，自引：0，他引：1  

P Stephenson  F B Satchell  G Allen  W H Andrews 《Journal of the Association of Official Analytical Chemists》1991,74(5):821-826

A preenrichment procedure and a direct selective enrichment procedure were compared for recovery of Salmonella artificially inoculated into liquid whole egg, egg yolk, and egg albumen. For liquid whole egg and egg yolk, the 2 procedures were comparable. With egg albumen, however, preenrichment in lactose broth gave significantly higher recoveries than did direct selective enrichment in either selenite cystine or tetrathlonate broths. The lactose preenrichment procedure was used to determine the survival of S. enteritidis in egg yolk and egg albumen over a period of 7 days. As shown by most probably number determinations, counts of S. enteritidis inoculated into egg albumen decreased by 3 log units, whereas those in egg yolk did not change significantly. It is recommended, therefore, that only the egg yolk be examined for this pathogen. In a comparison of 5 different preenrichment media (lactose broth, brain heart infusion broth, trypticase soy broth, buffered peptone water, and nutrient broth), lactose broth was somewhat less productive than the other 4 media for the recovery of Salmonella from egg yolks. Trypticase soy broth gave the highest recovery.  相似文献   

MCPA (4-Chloro-2-ethylphenoxyacetate) resistance in hemp-nettle (Galeopsis tetrahit L.)     

Weinberg T  Stephenson GR  McLean MD  Hall JC 《Journal of agricultural and food chemistry》2006,54(24):9126-9134

The physiological basis for MCPA resistance in a hemp-nettle (Galeopsis tetrahit L.) biotype, obtained from a MCPA-resistant field population, was investigated. Dose-response studies revealed that the resistance factor for MCPA, based on GR50 comparisons of total dry weight of resistant (R) and susceptible (S) plants, was 3.3. Resistance factors for fluroxypyr, dicamba, 2,4-D, glyphosate, and chlorsulfuron were 8.2, 1.7, 1.6, 0.7, and 0.6, respectively. MCPA resistance was not due to differences in absorption, because both R and S biotypes absorbed 54% of applied [14C]MCPA 72 h after treatment. However, R plants exported less (45 vs 58% S) recovered 14C out of treated leaves to the apical meristem (6 vs 13% S) and root (32 vs 38% S). In both biotypes, approximately 20% of the 14C recovered in planta was detected as MCPA metabolites. However, less of the 14C recovered in the roots of R plants was MCPA. Therefore, two different mechanisms protect R hemp-nettle from MCPA phytotoxicity: a lower rate of MCPA translocation and a higher rate of MCPA metabolism in the roots. In support of these results, genetic studies indicated that the inheritance of MCPA resistance is governed by at least two nuclear genes with additive effects.  相似文献   

The equine immune response to Streptococcus equi subspecies zooepidemicus during uterine infection   总被引：1，自引：0，他引：1  

Causey RC  Weber JA  Emmans EE  Stephenson LA  Homola AD  Knapp KR  Crowley IF  Pelletier DC  Wooley NA 《Veterinary journal (London, England : 1997)》2006,172(2):248-257

The purpose of this study was to describe strain-specific immune responses to Streptococcus equi subspecies zooepidemicus (S. zooepidemicus) during uterine infection in horses. Five isolates of S. zooepidemicus were differentiated into four strains antigenically by bactericidal testing in blood of 12 horses, and genetically by pulsed-field gel electrophoresis. Eight healthy mares were then divided into two groups, each inoculated with one strain intrauterinely on three successive oestrous cycles followed by a second strain for three successive cycles, first and second strains being reversed for each group. Immune responses to both strains were assessed by bactericidal testing and immunoblotting over eight cycles. Both techniques indicated that immune responses to each strain arose at different times. Immunoblots showed greater binding to the first inoculated strain than to the second (P < 0.05). These data confirm that immune responses to S. zooepidemicus during uterine infection are partly strain-specific.  相似文献   

Assessing disease risk at the wildlife–livestock interface: A study of Sierra Nevada bighorn sheep     

Deana L. Clifford  Brant A. Schumaker  Thomas R. Stephenson  Vernon C. Bleich  Maya L. Cahn  Ben J. Gonzales  Walter M. Boyce  Jonna A.K. Mazet   《Biological conservation》2009,142(11):2559-2568

Despite evidence that domestic sheep diseases threaten the persistence of bighorn sheep populations, the economic consequences of restricting domestic sheep grazing has polarized the debate, with some arguing that disease risk posed by domestic sheep has been exaggerated and grazing restrictions should be eased. We constructed a model to assess how different management strategies (grazing allotment closures, grazing time reductions, and reduced probability of stray domestic sheep) affect the risk of respiratory disease transmission from domestic sheep to endangered Sierra Nevada bighorn sheep, and to predict population-level impacts of an outbreak. Even when management strategies reduced risk of interspecies contact to less than 2% per year, our model predicted a 50% probability of a catastrophic respiratory disease outbreak during the next 10 bighorn sheep generations. If an outbreak occurs in the near future, the model predicts that the smallest Sierra Nevada bighorn sheep population would have a 33% probability of quasi-extinction. To eliminate all risk of contact and potential disease transmission, domestic sheep cannot be grazed on allotments that overlap with areas utilized by Sierra Nevada bighorn sheep. Where wildlife and domestic animal populations share limited habitat, and there is documented evidence of a substantial disease threat and extinction risk, stakeholders must recognize that the only way to eliminate contact and risk of disease transmission is to give priority to one species or the other. If conservation is the priority, difficult decisions will need to be made to balance trade-offs between economic livelihoods and species conservation.  相似文献   

Infertility associated with the absence of endometrial progesterone receptors in a bitch          下载免费PDF全文

JC Dockweiler  B Cossic  CG Donnelly  RO Gilbert  E Buckles  SH Cheong 《Reproduction in domestic animals》2017,52(1):174-178

A three‐year‐old intact female Old English sheepdog was presented for evaluation of infertility. A uterine biopsy was performed during dioestrus, and the microscopic appearance was inconsistent with progesterone stimulation; the glands were sparse, simple and failed to show coiling, while the glandular epithelium was cuboidal instead of columnar. There was very little evidence of glandular activity. Due to the inappropriate appearance of the glands for the stage of the cycle, immunohistochemistry for progesterone receptors was performed. No progesterone receptor‐positive immunoreactivity was identified in the endometrial luminal epithelium, glandular epithelium or stroma. Weak intranuclear immunoreactivity was identified within the smooth muscle cells of the myometrium. The absence of progesterone receptors within the endometrial glands is the most likely explanation for the abnormal appearance of the endometrium and for this bitch's infertility. To our knowledge, this is the first report of endometrial progesterone receptor absence in a bitch.  相似文献   

Screening for dilated cardiomyopathy in great danes in the United kingdom     

HM Stephenson  S Fonfara  J López-Alvarez  P Cripps  J Dukes-McEwan 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2012,26(5):1140-1147

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Buffer zone and windbreak effects on spray drift deposition in a simulated wetland     

Brown RB  Carter MH  Stephenson GR 《Pest management science》2004,60(11):1085-1090

The amount of agricultural spray that drifts into a wetland from an adjacent crop field is influenced by vegetation along the field boundary or any intentional setback distance (buffer zone) between the sprayer and the edge of the arable field. In this study, spray tracer drift deposits were measured in a simulated wetland area under different conditions of wind speed and buffer zone width. The effect of an artificial windbreak at the upwind edge of the simulated wetland was also evaluated. A level of tolerance of 0.1% of the in-swath spray deposition was established as a no-effect level for the response of aquatic plants to common herbicides. Our results indicate that a vegetated 10-m field margin (eg a fencerow) alone provides adequate protection from herbicide drift into a wetland area under wind conditions normally considered acceptable for spraying. For high winds (> 4m s(-1)) when field spraying would not normally be advised, adequate protection was afforded by the same 10-m margin plus a dense windbreak (25% porosity) or by the margin plus a 20-m buffer zone.  相似文献   

Septicaemia and septic arthritis in a neonatal calf caused by Lactococcus lactis     

Wichtel ME  Fenwick SG  Hunter J  Stephenson A  Martin D  Wichtel JJ 《The Veterinary record》2003,153(1):22-23

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Lay TB testing     

Stephenson RS 《The Veterinary record》2003,153(5):156

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Development of an enzyme-linked immunosorbent assay for the detection of dicamba   总被引：4，自引：0，他引：4  

Clegg BS  Stephenson GR  Hall JC 《Journal of agricultural and food chemistry》2001,49(5):2168-2174

A competitive indirect enzyme-linked immunosorbent assay (CI-ELISA) was developed to quantitate the herbicide dicamba (3,6-dichloro-2-methoxybenzoic acid) in water. The CI-ELISA has a detection limit of 2.3 microg L(-1) and a linear working range of 10--10000 microg L(-1) with an IC(50) value of 195 microg L(-1). The dicamba polyclonal antisera did not cross-react with a number of other herbicides tested but did cross-react with a dicamba metabolite, 5-hydroxydicamba, and structurally related chlorobenzoic acids. The assay was used to estimate quantitatively dicamba concentrations in water samples. Water samples were analyzed directly, and no sample preparation was required. To improve detection limits, a C(18) (reversed phase) column concentration step was devised prior to analysis, and the detection limits were increased by at least by 10-fold. After the sample preconcentration, the detection limit, IC(50), and linear working range were 0.23, 19.5, and 5-200 microg L(-1), respectively. The CI-ELISA estimations in water correlated well with those from gas chromatography-mass spectrometry (GC-MS) analysis (r(2) = 0.9991). This assay contributes to reducing laboratory costs associated with the conventional GC-MS residue analysis techniques for the quantitation of dicamba in water.  相似文献