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821.
A sero‐epidemiological study on canine leptospirosis was conducted in house, stray, farm and hunting dogs, as well as in suspect cases of clinical canine leptospirosis. Serum samples were collected from apparently healthy (vaccinated and non‐vaccinated), house dogs. A questionnaire was administered to the owners to elicit information on risk factors for leptospirosis. The microscopic agglutination test was used to screen for leptospirosis using 17 international serovars. Reciprocal titres of between 100 and <800 were considered as evidence of past exposure while reciprocal titres of 800 or greater were classified as suggestive of acute/current infection. Of a total of 419 serum samples tested, 61 (14.6%) were seropositive for Leptospira agglutinins, 23 (5.5%) had mixed infections and 16 (3.8%) had current infection. Amongst 50 suspected cases of clinical leptospirosis, 24 (48.0%) were seropositive and only 13 (26.0%) had current infection compared with 10 (6.3%) and three (1.9%) of 160 apparently healthy house dogs respectively. The difference was statistically significant (P < 0.05; χ2). Twelve (25.5%) of 47 hunting dogs, 10 (20.4%) of 49 farm dogs and five (4.4%) of 113 stray dogs were seropositive (P < 0.05; χ2). Overall, a total of nine serovars were detected with serovars mankarso, icterohaemorrhagiae RGA, autumnalis and copenhageni being involved in 29 (47.5%), 20 (32.8%), 25 (41.0%) and 10 (16.4%) respectively in 61 seropositive dogs (P < 0.05; χ2). Serovar mankarso was most predominant in seropositive apparently healthy dogs, 37.8% (14/37), suspected clinical cases of leptospirosis, 62.5% (15/24) compared with serovar icterohaemorrhagiae with a frequency of 21.6% (8/37) and 50.0% (12/24), the difference being statistically significant (P < 0.05; χ2). Although all vaccines used for prevention of canine leptospirosis in the country contain serovars canicola and icterohaemorrhagiae, serovar mankarso was mostly associated with infection and disease and may be a good candidate for inclusion in the vaccine used locally. The public health risk posed to owners of dogs infected with Leptospira cannot be over‐emphasized considering the zoonotic nature of the disease.  相似文献   
822.
ObjectiveTo compare the recovery after anaesthesia with isoflurane, sevoflurane and desflurane in dogs undergoing magnetic resonance imaging (MRI) of the brain.Study designProspective, randomized clinical trial.AnimalsThirty‐eight dogs weighing 23.7 ± 12.6 kg.MethodsFollowing pre‐medication with meperidine, 3 mg kg?1 administered intramuscularly, anaesthesia was induced intravenously with propofol (mean dose 4.26 ± 1.3 mg kg?1), the trachea was intubated, and an inhalational anaesthetic agent was administered in oxygen. The dogs were randomly allocated to one of three groups: group I (n = 13) received isoflurane, group S (n = 12) received sevoflurane and group D (n = 13) received desflurane. Parameters recorded included cardiopulmonary data, body temperature, end‐tidal anaesthetic concentration, duration of anaesthesia, and recovery times and quality. Qualitative data were compared using chi‐squared and Fisher's exact tests and quantitative data with anova and Kruskal–Wallis test. Post‐hoc comparisons for quantitative data were undertaken with the Mann–Whitney U‐test.ResultsThe duration of anaesthesia [mean and standard deviation (SD)] in group I was: 105.3 (27.48) minutes, group S: 120.67 (19.4) minutes, and group D: 113.69 (26.68) minutes (p = 0.32). Times to extubation [group I: 8 minutes, (interquartile range 6–9.5), group S: 7 minutes (IQR 5–7), group D: 5 minutes (IQR 3.5–7), p = 0.017] and to sternal recumbency [group I: 11 minutes (IQR 9.5–13.5), group S: 9.5 minutes (IQR 7.25–11.75), group D: 7 minutes (range 3.5–11.5), p = 0.048] were significantly different, as were times to standing. One dog, following sevoflurane, had an unacceptable quality of recovery, but most other recoveries were calm, with no significant difference between groups.Conclusions and clinical relevanceAll three agents appeared suitable for use. Dogs’ tracheas were extubated and the dogs recovered to sternal recumbency most rapidly after desflurane. This may be advantageous for animals with some neurological diseases and for day case procedures.  相似文献   
823.
The levels of selected mycotoxins and mold contamination of Ontario field-dried hay from 10 performance horse farms were examined. The farm owner, trainer or manager was questioned regarding their opinion of the quality of the hay. Half of the hay sampled showed potentially significant levels of mycotoxins, mold and actinomycete contamination. Subjective opinion did not correlate to objective analysis. Deoxynivalenol (vomitoxin), T 2 toxin and zearalenone were measured with vomitoxin present in the highest amounts. Vomitoxin is among the mycotoxins most frequently found as contaminants in cereal crops, in temperate climates, in North America. It can be concluded that the levels found in this study could potentially have an influence on the health of horses consuming such hay.  相似文献   
824.
825.
We examined variation at four isozyme and seven microsatellite loci in natural populations of Brassica oleracea L. on the coast of Dorset. All loci were polymorphic, and the diversity index of isozyme loci was similar to that of the microsatellites. Both microsatellites and isozymes showed significant spatial differentiation of genetic variation, but the scale differed between the marker types. Significant non-random mating at isozyme loci was detected within small groups of about five plants, in which adjacent individuals were separated by less than 5 m. On the other hand, non-random mating at microsatellite loci was only detected within the Dorset region as a whole. FST was significant for all loci and there was evidence of isolation by distance at both microsatellite and isozyme loci. From these data we infer that there is low but significant amounts of gene flow among B. oleracea populations in Dorset. The differences in the genetic structure between the two types of marker may be due to higher mutation rates at the microsatellite loci; however, the data suggest that stepwise gain or loss of single repeat units is not the principal mechanism.  相似文献   
826.
Canada was the largest durum wheat (Triticum turgidum var durum) producer in 1994, and in recent years supplied over 70% of world export trade in durum. Breeding for pasta quality is, therefore, a primary objective in Canadian durum breeding programs. Control of cultivar registration and stringent grading standards ensure that durum of consistent high quality is produced for domestic and export markets. The objectives of breeding programs include: improvement of traits related to production concerns, such as grain yield, disease resistance and sprouting resistance, and those related to end-use quality, such as protein concentration and quality; milling quality factors, such as semolina yield; colour of the wheat, semolina and pasta; and cooking quality. Selection and testing for quality begins at very early generations and becomes more stringent for advanced inbred lines. Selection is practised at the F1 or F2, where appropriate, using monoclonal antibodies to identify desirable gamma gliadins (γ-45 ) or low molecular weight glutenin subunits (LMW 2) that have been shown to be related to end-use quality. Grain from early generation yield trials, starting at F4, is screened for protein concentration and pigment content by Near Infrared reflectance, and for gluten strength by sodium dodecyl sulphate (SDS) sedimentation and micro-mixograph. Promising lines entered into multi-location yield trials are screened with more time-consuming procedures to fully assess suitability for pasta processing. These tests include semolina yield, ash and colour, and predictions of gluten strength such as mixograph and alveograph, and cooking quality. Candidate cultivars with quality equal to or better than the mean of the check cultivars can be proposed for registration after three years in the Durum Cooperative Test. It takes approximately 10 years from performing a cross to registrating a new cultivar. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   
827.
Gonipterus scutellatus is a significant insect pest of eucalypts in most countries where that genus has been introduced, but is usually only of minor significance in its native Australia. Because of this, much of the research on its biology and host preferences has been done outside Australia. This fact has the potential to produce misleading results as the insect may be forced to choose less preferred hosts, if normally preferred species are unavailable. In part of its native range, in Tasmania, oviposition of G. scutellatus was recorded on seven naturally co-occurring Eucalyptus species that were planted in even aged, replicated plots. Among the seven species were the economically important species, E. globulus and E. viminalis, which have been previously reported as highly preferred hosts. Within plots, oviposition occurred most commonly on three peppermint species (E. pulchella, E. tenuiramis and E. amygdalina) and was rare or absent on the other species (E. globulus, E. viminalis, E. ovata and E. obliqua). Of the peppermints, E. pulchella was the most preferred species for oviposition at this site. A low percentage of peppermints in mixed forest (containing these seven species) immediately adjacent to plots was always matched by low numbers of G. scutellatus eggs within plots; but high percentages of peppermints outside plots could either be matched by high or low numbers of eggs within plots. In the discussion, we suggest that previous studies of G. scutellatus host range may have been limited because the insect was not exposed to hosts it naturally encounters.  相似文献   
828.
The karyotype and chromosomal characteristics of the yellowtail kingfish Seriola lalandi lalandi were investigated by examining metaphase spreads from kidney cells of 4-month-old fish artificially bred using wild-captured broodstock from the coast of South Australia. A total of 80 mitotic metaphases from 10 individual fish were analysed, with 52 spreads having a mode of 2 n =48 chromosomes, representing 65% of the metaphases observed. The diploid consisted of two metacentric, two submetacentric, six subtelocentric and 38 telocentric chromosomes, with the fundamental number of chromosome arms being 52. The total haploid chromosome length was approximately 44.412 μm. This study shows that the karyotype of S. lalandi lalandi differs from those reported previously for other Seriola species in having one pair of metacentric chromosomes.  相似文献   
829.
In this study, the effects of three commonly used chemicals, dimethyl sulphoxide (DMSO), ethylene glycol (EG), propylene glycol (PG) and their combinations with trehalose, were evaluated on the cryopreservation of D‐larvae of the blue mussel Mytilus galloprovincialis. The larvae were harvested 30 h post‐fertilization at 21 °C and cryopreserved using a standard protocol in 5%, 10% or 15% of DSMO, EG and PG either as single chemical solutions or in combination with 0.2 M trehalose. Among these cryoprotectants, 5% DMSO resulted in the highest post‐thaw survival rate of 55.3±7.8%, although it did not significantly differ from those with 10% and 15% EG. The addition of 0.2 M trehalose did not improve the post‐thaw larval survival rates in all the combinations assessed. The cryo‐effects on subsequent development were evaluated using the D‐larvae frozen with 5% DMSO. The results showed that cryopreservation affected both larval survival and growth in this species. The relative daily mortality rate was significantly higher in treated than control groups over the period from 3 h post‐thaw to day 11 post‐fertilization. On day 6 post‐fertilization, the average larval length in the treated group was significantly smaller than that in the control. From day 11 post‐fertilization, and onwards, differences in these two traits were not significant between treated and control groups. On day 21 post‐fertilization, about 80% of the larvae in both treated and control groups developed eyes and the normalized survival rate in the treated group was 12.5%.  相似文献   
830.
Since the 1950s, pesticide resistance has been identified in many species. This paper considers the role of resistance action groups and notes that they were all formed in response to resistance problems occurring. Data now exist on the strategies which are most effective and the paper aims to bring together information from the fields of weeds, pests and diseases. Pesticide mixtures, sequences or rotations have been demonstrated as having a clear role in resistance management strategies. Resistance management would be improved if there was agreement on uniform test methodology and interpretation of results. The industry must work together to agree what constitutes an anti-resistance strategy, whether this is for prevention or cure, and to ensure that this is then included within regulatory frameworks. Future developments such as patch treatment, biotechnology and biocontrol are discussed. It is concluded that, to date, there has been little discussion between specialists in the field of resistance to herbicides, fungicides or insecticides and it is clear there are significant advantages to be had from more interaction. ©1997 SCI  相似文献   
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