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排序方式: 共有116条查询结果,搜索用时 62 毫秒
81.
Raksha Bhoora Linda Franssen Marinda C. Oosthuizen Alan J. Guthrie Erich Zweygarth Barend L. Penzhorn Frans Jongejan Nicola E. Collins 《Veterinary parasitology》2009
A molecular epidemiological survey of the protozoal parasites that cause equine piroplasmosis was conducted using samples collected from horses and zebra from different geographical locations in South Africa. A total of 488 samples were tested for the presence of Theileria equi and/or Babesia caballi using the reverse line blot hybridization assay. Ten percent of the samples hybridized to the Theileria/Babesia genus-specific probe and not to the B. caballi or T. equi species-specific probes, suggesting the presence of a novel species or genotype. The small subunit of rRNA gene (18S; ∼1600 bp) was amplified and sequenced from 33 of these 488 samples. Sequences were compared with published sequences from the public sequence databases. Twelve distinct T. equi and six B. caballi 18S rRNA sequences were identified. Alignments demonstrated extensive sequence variation in the V4 hypervariable region of the 18S rRNA gene within T. equi. Sequence variation was also found in B. caballi 18S rRNA genes, although there was less variation than observed for T. equi. Phylogenetic analysis based on 18S rRNA gene sequences revealed three T. equi clades and two B. caballi clades in South Africa. The extent of sequence heterogeneity detected within T. equi and B. caballi 18S rRNA genes was unexpected since concerted evolution is thought to maintain homogeneity within repeated gene families, including rRNA genes, in eukaryotes. The findings reported here show that careful examination of variants of the 18S rRNA gene of T. equi and B. caballi is required prior to the development of molecular diagnostic tests to detect these parasites in horses. Species-specific probes must be in designed in regions of the gene that are both conserved within and unique to each species. 相似文献
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Resistance to intestinal coccidiosis following DNA immunization with the cloned 3-1E Eimeria gene plus IL-2, IL-15, and IFN-gamma 总被引:5,自引:0,他引:5
A cloned Eimeria acervulina gene (3-1E) was used to vaccinate chickens in ovo against coccidiosis, both alone and in combination with genes encoding interleukin (IL)-1, IL-2, IL-6, IL-8, IL-15, IL-16, IL-17, IL-18, or interferon (IFN)-gamma. Vaccination efficacy was assessed by increased serum anti-3-1E antibody titers, reduced fecal oocyst shedding, and enhanced body weight gain following experimental infection with E. acervulina. When used alone, anti-3-1E antibody titers were transiently, but reproducibly, increased at 2 wk and 3 wk posthatching in a dose-dependent manner. Similarly, significantly reduced oocyst shedding and increased weight gain were observed at relatively high-dose 3-1E vaccinations (> or =25 microg/egg). Combined immunization with the 3-1E and IL-1, IL-2, IL-15, or IFN-gamma genes induced higher serum antibody responses compared with immunization with 3-1E alone. Following parasite infection, chickens hatched from embryos given the 3-1E gene plus the IL-2 or IL-15 genes displayed significantly reduced oocyst shedding compared with those given 3-1E alone, while 3-1E plus IL-15 or IFN-gamma significantly increased weight gain compared with administration of 3-1E alone. Taken together, these results indicate that in ovo immunization with a recombinant Eimeria gene in conjunction with cytokine adjuvants stimulates protective intestinal immunity against coccidiosis. 相似文献
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Brigitte Moser Jochen A. G. Jaeger Ulrike Tappeiner Erich Tasser Beatrice Eiselt 《Landscape Ecology》2007,22(3):447-459
Patch-based landscape metrics can be biased by the boundaries and the extent of a reporting unit if the boundaries fragment
patches. We call this the “boundary problem”. The effective mesh size m
eff is a convenient method to quantify landscape fragmentation, that is based on the probability that two points chosen randomly
in a region will be connected, e.g., not be separated by roads, railroads, or urban development. The cutting-out (CUT) procedure,
used in the original computation of m
eff, suffers from the boundary problem because the boundaries of the reporting units are considered to be additional barriers.
Therefore, m
eff will be underestimated, particularly if reporting units are embedded within the broader landscape. In this paper, we present
a solution to overcome this limitation by a new method called “cross-boundary connections” (CBC) procedure. It attributes
the connections between two points that are located in different reporting units to both reporting units. We systematically
compare the CBC procedure to the CUT procedure and show that the boundary problem is intrinsic to the CUT procedure, while
the CBC procedure is independent of the size and administrative boundaries of reporting units. In addition, we elucidate the
superior performance of the new procedure in the case study of South Tyrol where m
eff is being used for sustainability reporting on the level of municipalities. The new CBC procedure eliminates the bias due
to the boundaries and the size of reporting units in measuring landscape fragmentation through m
eff. 相似文献
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Haerdi-Landerer C Steiner A Linke B Wahl D Schneider E Hehli M Frei R Auer JA 《Veterinary surgery : VS》2002,31(6):582-588
OBJECTIVE: To compare the mechanical properties of 2 configurations of a veterinary fixation system (VFS) for large animal long bones with dynamic compression plating (DCP). SAMPLE POPULATION: Eighteen pairs of Canevasit tubes (Canevasit; Amsler und Frei, Schinznach Dorf, Switzerland) (length, 170 mm; diameter, 47.5 mm; cortex thickness, 10 mm), aligned with a 10-mm gap, and stabilized with 2 DCP or 2 VFS implants. METHODS: Three groups (n = 6) were compared. Group 1 Canevasit tubes were stabilized with two 10-hole, broad 4.5-mm stainless steel DCP applied with both plates centered over the gap, in orthogonal planes parallel to the long axis of the tubes and staggered to allow bicortical fixation with ten 4.5-mm, 52-mm-long cortex screws each. Group 2 tubes were stabilized similarly with 2 VFS implants, each composed of a stainless steel rod (length, 167 mm; diameter, 8 mm), and 10 clamps were applied in alternating fashion left and right on the rod and fixed bicortically with ten 4.5-mm, 52-mm-long, cortex screws. Group 3 tubes were stabilized similarly, but using only 6 clamps/rod. All groups were tested initially in torsion within elastic limits and subsequently in 4-point bending, with 1 implant on the tension side, until gap closure occurred. RESULTS: None of the constructs failed, but all had plastic deformation after 4-point bending. No statistically significant differences were found among the 3 groups in torsional stiffness. Double DCP fixation was significantly stiffer and stronger in 4-point bending, compared with both configurations of double VFS fixation. CONCLUSIONS: The plate design was favored in this study. The VFS system may have to be adapted before further tests are conducted. Test modalities have to be chosen closer to clinical conditions (real bone, cyclic loading, closed gap). CLINICAL RELEVANCE: The veterinary fixation system has not yet proven its advantages for large animal long bone fracture repair. From the pure mechanical point of view, double DCP is the favored method for the treatment mentioned. 相似文献