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Sara Sánchez-Moreno Sean Smukler Howard Ferris Anthony T. O’Geen Louise E. Jackson 《Biology and Fertility of Soils》2008,44(5):727-744
The aim of this paper was to assess biodiversity among different habitats of an organic farm and the relationships between
some soil properties, nematode taxonomic diversity, and soil food web condition. Eight habitats were studied in the farm:
ponds, ditches, a riparian corridor, hedgerows, and four agricultural fields (mustard, oats, fallow, and legumes). The undisturbed
riparian corridor had higher soil and concentrations, and potentially mineralizable N and higher abundances of bacterivore nematodes and longer food webs. Canonical
correlation analysis showed associations between habitats and nematode trophic groups: predatory and bacterial-feeding nematodes
in the riparian corridor and hedgerows, omnivore nematodes in the ponds and ditches, and fungal-feeding nematodes in the legume
field. Soil chemical and physical properties mirrored the aboveground farm patterns and were more similar among habitats that
were or had been cultivated, compared to the riparian corridor. Soil food web indices, based on functional analysis of nematode
faunal composition, reflected the aboveground landscape heterogeneity. Discriminant analysis indicated that soil food web
indices separated the two most disturbed habitats (ponds and tailwater ditches) from the two least disturbed habitats (the
riparian corridor and hedgerows). The indices correlated with soil functioning as inferred by soil properties. Abundance of
nematode taxa was not associated with aboveground landscape patterns. The complexity of the soil food web may have been influenced
by (1) environmental factors that differed between years, (2) different time periods since disturbance in the various habitats,
and (3) movement of nutrients and organisms by water flow between habitats in the farmscale. 相似文献
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Ghaemi A Soleimanjahi H Bamdad T Soudi S Arefeian E Hashemi SM Ebtekar M 《Comparative immunology, microbiology and infectious diseases》2007,30(4):197-210
Previously, we have reported that the injection of an expression vector containing Herpes simplex virus (HSV) Glycoprotein D-1 (gD-1) generated a significant antibody response in mice and protected them against HSV lethal challenge. We tested its potential to induce antibody and cell mediated immune responses in latently infected mice. Positive control group (KOS) and HSV gD-1 vaccinated mice demonstrated protection against a lethal ocularly challenge of 10(5.5) plaque-forming units (pfu)/eye of wild HSV-1 versus negative control groups. For neutralizing antibody titers, delayed-type hypersensitivity (DTH), lymphocyte proliferation responses, clinical evaluation and survival following lethal challenge, no considerable difference was observed between mice vaccinated with DNA plasmid and those vaccinated with KOS. KOS-vaccinated mice demonstrated the ability to completely prevent latency whereas DNA vaccinated group showed some degree of protection and displayed less latency than negative control groups and had considerably high levels of IFN-gamma and strong CTL responses versus negative control groups. It can be concluded that although immunization with the DNA vaccine is more effective in both protecting mice and induction of immune response, however it could not completely block the latent infection in sensory nerves. 相似文献
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Sara J. Bruce BVMS W.G. GUILFORD BVSc PhD Duncan I. Hedderley Miho Mccauley 《Veterinary radiology & ultrasound》1999,40(5):472-476
Ten healthy dogs were fed 30 1.5 mm and 10 5 mm radiopaque markers (BIPS, MedID, Grand Rapids) mixed with sufficient quantities of a high fibre diet to meet 25% of their estimated daily caloric requirements. Abdominal radiographs were made at two hour intervals until 90% of the small and large markers had left the colon. The mean residence times (MRT) of each size of marker in the proximal, distal and total colon were calculated using kinetic analysis. The MRT's of the small markers were 4.9 hours (SD 4.4), 7.1 hours (SD 3.3) and 12.0 hours (SD 7.1) respectively. The MRT's of the large markers were not significantly different from the small markers except in the proximal colon where they were significantly shorter (3.2 hours, SD 2.3). Reference colonic filling and colonic transit curves for both sizes of markers were constructed. These may be useful to detect abnormal colonic transit in dogs. 相似文献