THE TRANSMISSION OF TWO NEW AUSTRALIAN SEROTYPES OF BLUETONGUE VIRUS TO SHEEP     

K. R. E. SQUIRE  M. F. UREN  T. D. ST  GEORGE 《Australian veterinary journal》1981,57(6):301-301

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Interactions Between Nutrition and Reproduction in the Pig     

JR Cosgrove    ST Charlton    SJ Cosgrove    W. Zak  GR Foxcroft 《Reproduction in domestic animals》1995,30(4):193-200

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Association of Pythium coloratum and Pythium sulcatum with cavity spot disease of carrots in Western Australia     

K. A. EL-TARABILY  G. E. ST. J. HARDY  & K. SIVASITHAMPARAM 《Plant pathology》1996,45(4):727-735

All 170 Pythium isolates from carrot cavity spot lesions from a field in Western Australia were found to belong to either P. coloratum or P. sulcatum . All isolates of P. coloratum produced large, brownish-black, water-soaked and depressed lesions on mature carrots inoculated with agar plugs colonized by the pathogen. In comparison, only a few isolates of P. sulcatum produced lesions and these were small. In glasshouse trials, P. coloratum produced substantial and numerous lesions at an inoculum density of 0.5% (weight of millet seed-based inoculum/weight of soil), whilst P. sulcatum produced few and small lesions at inoculum densities of 0.8 and 1% and none at 0.5%. This is the first record of P. coloratum as a causal agent of cavity spot of carrots.  相似文献   

The early development of disease caused by Phytophthora cinnamomi in Eucalyptus marginata and Eucalyptus calophylla grooving in rehabilitated bauxite mined areas     

G. E. ST J. HARDY  I. J. COLQUHOUN  P. NIELSEN 《Plant pathology》1996,45(5):944-954

The soil-borne plant pathogen Phytophthora cinnamomi is widely distributed in the jarrah ( Eucalyptus marginata ) forest of Western Australia. Infested areas of the forest are mined for bauxite and the presence of the pathogen could after the survival of trees re-established after mining. Monitoring of 21 revegetated bauxite mined areas found that survival of jarrah and marri ( Eucalyptus calophylla ) trees was high (85–92% and 93–99%, respectively) after 5–7 years but P. cinnamomi was recovered from dead trees. To identify trees for more detailed study, plant symptoms of stress such as suppressed growth, wilting, yellowing of crown, coppice and epicormic growth and visible stem lesions were used. Over a period of 15 months, 30 E. marginata and 28 E. calophylla were carefully excavated and examined for lesions and the presence of P. cinnamomi. P. cinnamomi was consistently isolated from the lignotuber and collar regions of both hosts but never from the roots alone, except in one instance from E. calophylla where it was isolated from a non-lesioned root. In E. calophylla , the lignotuber appears to be very susceptible to invasion by P. cinnamomi in contrast to the roots which appear resistant. The invasion of the pathogen into the lignotuber and collar regions of both species was consistently associated with ponding of water around the plants. This ponding persists for many hours to days after rain and appears to provide an infection court for P. cinnamomi. Development of rehabilitation procedures to reduce this ponding will minimize the risk of tree deaths caused by this pathogen.  相似文献   

The ability of Phytophthora cinnamomi to infect through unwounded and wounded periderm tissue of Eucalyptus matginata     

E. O'GARA  G. E. ST. J. HARDY  J. A. McCOMB 《Plant pathology》1996,45(5):955-963

Unwounded and wounded periderm tissue of 1-year old stems of Eucalyptus marginata were infected and lesioned after 5 days'exposure to either mycelium or motile zoospores of Phytophthora cinnamomi. Lesions produced by P. cinnamomi were longer in wounded than in unwounded stems. The inclusion of non-sterile mine site soil with inocula in the unwounded treatments did not affect the rate or extent to which P. cinnamomi colonized E. marginata stem tissue. The ability of P. cinnamomi zoospores to infect unwounded suberized woody tissue of E. marginata , has important implications for mine site rehabilitation in P. cinnamomi infested areas. This is the first study to demonstrate clearly that zoospores of P. cinnamomi can infect and invade unwounded suberized tissue.  相似文献   

EXPERIMENTAL INFECTION OF CULICOIDES WITH A BLUETONGUE VIRUS ISOLATED IN AUSTRALIA     

H.A. STANDFAST  T.D. ST  GEORGE  D.H. CYBINSKI  A.L. DYCE  C.A. McCAUGHAN 《Australian veterinary journal》1978,54(9):457-458

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Use of Vaginal Electrical Resistance to Diagnose Oestrus,Dioestrus and Early Pregnancy in Synchronized Tropically Adapted Beef Heifers     

CD Hockey  ST Norman  JM Morton  D Boothby  NJ Phillips  MR McGowan 《Reproduction in domestic animals》2010,45(4):629-636

The primary objective of this study was to determine whether a single measurement of intravaginal electrical resistance (VER), using the commercially available Ovatec^® probe, can discriminate between dioestrus and oestrus in Bos indicus females, which had been treated to synchronize oestrus. Santa Gertrudis heifers (n = 226) received one of three oestrous synchronization treatments: double PGF_2α 10 days apart, 8‐day controlled internal drug release (CIDR) treatment or CIDR pre‐synchronization + PGF_2α 10 days after CIDR removal. The heifers were inseminated within 12 h following observed oestrus, or, if not observed, at a fixed time approximately 80 h, following the last synchronization treatment. They were palpated per rectum for signs of pregnancy 9 weeks after artificial insemination (AI). Vaginal electrical resistance measurements were taken at the completion of synchronization treatments (presumed dioestrus), immediately prior to AI (oestrus), and then at 3 and 9 weeks post‐AI. Mean VER differed between presumed dioestrus and oestrus (113.7 vs 87.4, p < 0.001). The area under the receiver operating characteristics (ROC) curve was 0.925, indicating that VER was highly discriminatory between dioestrus and oestrus. Vaginal electrical resistance at time of AI was negatively associated with odds of conception when all inseminations were included in the analyses [odds ratio (OR) = 0.97; 95% CI 0.95–1.00; p = 0.018], but not when fixed time AIs were excluded (OR = 1.00; 95% CI 0.97–1.03; p = 0.982). Mean VER readings differed between pregnant and non‐pregnant animals at both 3 weeks (120.5 vs 96.7, p < 0.001) and 9 weeks (124.0 vs 100.3, p < 0.001) post‐AI. However, 3‐ and 9‐week VER measurements were not highly discriminatory between pregnancy and non‐pregnancy (area under ROC curve = 0.791 and 0.736, respectively). Mean VER at time of AI for animals diagnosed in oestrus differed between each of the oestrous synchronization treatments (84.7, 73.6 and 78.9, groups 1–3 respectively, p < 0.001). These findings suggest that measurement of VER may improve accuracy of oestrus diagnoses when selecting cattle for AI following oestrous synchronization programmes involving tropically adapted cattle.  相似文献   

Coupling ecosystem and individual‐based models to simulate the influence of environmental variability on potential growth and survival of larval sprat (Sprattus sprattus L.) in the North Sea     

UTE DAEWEL  MYRON A. PECK  WILFRIED KÜHN  MICHAEL A. ST. JOHN  IRINA ALEKSEEVA  CORINNA SCHRUM 《Fisheries Oceanography》2008,17(5):333-351

To investigate the impact of changing environmental conditions in the North Sea on the distribution and survival of early life stages of a marine fish species, we employed a suite of coupled model components: (i) an Eulerian coupled hydrodynamic/ecosystem (Nutrients, Phyto‐, Zooplankton, Detritus) model to provide both 3‐D fields of hydrographical properties, and spatially and temporally variable prey fields; (ii) a Lagrangian transport model to simulate temporal changes in cohort distribution; and (iii) an individual‐based model (IBM) to depict foraging, growth and survival of fish early life stages. In this application, the IBM was parameterized for sprat (Sprattus sprattus L.) and included non‐feeding (egg and yolk‐sac larval) stages as well as foraging and growth subroutines for feeding (post‐yolk sac) larvae. Sensitivity analyses indicated that the angle of visual acuity, assimilation efficiency and the maximum food consumption rate were the most critical intrinsic model parameters. As an example, we applied this model system for 1990 in the North Sea. Results included not only information concerning the interplay of temperature and prey availability on larval fish survival and growth but also information on mechanisms underlying larval fish aggregation within frontal zones. The good agreement between modelled and in situ estimates of sprat distribution and growth rates in the German Bight suggested that interconnecting these different models provided an expedient tool to scrutinize basic processes in fish population dynamics.  相似文献   

旋毛虫感染兔血清抗体消长规律的研究   总被引：1，自引：0，他引：1  

张北民  张惠英 《中国兽医寄生虫病》2000,8(2):16-18

应用旋毛虫肌幼虫干燥冷浸可溶性抗原与聚醛化聚苯乙烯（ＰＡＰＳ）载体微球共价交联制成快诊试剂,对旋毛虫感染兔血清进行检测,初步探明其血清抗体的消长规律。实验显示,以１６０００条肌幼虫／只经口饲喂感染１０只兔,于第７天可检出抗体,并分别于感染后第４５￣４９天先后达到抗体最高水平,然后维持一段时间（２０￣３０天左右）,以后逐渐缓缓下降。此结果与旋毛虫肌幼虫感染宿主后的生活周期相吻合。肌幼虫在肠道内发育为  相似文献   

Variations in the drift of larval cod (Gadus morhua L.) in the Baltic Sea: combining field observations and modelling     

RÜdiger Voss  Hans-Harald Hinrichsen  & Mike ST John 《Fisheries Oceanography》1999,8(3):199-211

Coupled three-dimensional (3-D) physical oceanographic modelling and field sampling programmes were carried out in May 1988 and August 1991 to investigate the potential drift of larval cod ( Gadus morhua L.) in the Bornholm Basin of the Baltic Sea. The goals were to predict the transport of cod larvae, thus aiding the identification of physical processes influencing larval retention/dispersal. Numerical simulations were performed using a 3-D eddy-resolving baroclinic model based on the Bryan–Cox–Semtner code adapted for the Baltic Sea. Within the Bornholm Basin, the model was initialized with ground truth data of physical parameters obtained on the research cruises, and all simulations were forced with actual wind data. Outside the basin, generalized hydrographic features of the Baltic Sea were utilized by incorporation of simulated hydrographic fields from previous model runs typical for the time periods considered. Larval drift was simulated either by incorporation of passive drifters, or as the initial horizontal distribution of larvae implemented into the model. Drift model simulations of larval transport agreed relatively well with field observations. The influence of variations in the vertical distribution on a smaller scale, i.e. vertical deviations of ± 6 m from the observed mean centre of mass, on the drift was examined, revealing no significant differences in the drift of larvae depending on their vertical distribution. The different wind forcing during the investigated time periods was linked to a retention situation in May 1988 and to a dispersal situation in August 1991. Finally, observed spatial distribution patterns of 1-group cod based on Baltic Young Fish Surveys (BYFS) were compared with their predicted transport in the larval phase and examined with respect to recruitment.  相似文献