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131.
Tick-borne fever, caused by a rickettsia-like organism, Cytoecetes phagocytophila, is transmitted by the sheep tick Ixodes ricinus. An electron microscopic technique was developed to examine I ricinus for C phagocytophila infection. Infected and uninfected ticks were obtained from a laboratory maintained tick culture. All stages of I ricinus collected from one field site were examined; 44 per cent of nymphae and 32 per cent of adults were infected with C phagocytophila, but larvae were uninfected. This supports the previously held theory of transtadial, but not transovarial transmission of tick-borne fever. 相似文献
132.
James H. Tidwell Carl D. Webster Shawn D. Coyle Greg Schulmeister 《Journal of the World Aquaculture Society》1998,29(1):79-83
Juvenile largemouth bass Micropterus salmoides , trained to accept artificial diets, were stocked into six 0.04-ha ponds at stocking densities of either 6,175 or 12,350 fish/ha. Fish were fed a floating custom-formulated diet, containing 44% protein, once daily to satiation for 12 mo (May 1994–May 1995). At final harvest, the total yield of fish was significantly greater (P < 0.05) and feed conversion ratio (FCR) was significantly lower, for bass stocked at the higher density (4,598 kg/ha and 2.3, respectively) than when stocked at the lower density (2,354 kg/ha and 3.3, respectively). There was no significant difference (P > 0.05) in average weight, length, or survival of bass stocked at the two densities. Averaged over the study period, there were no significant differences (P > 0.05) in total ammonia-nitrogen (TAN), nitrite-nitrogen, or un-ionized ammonia concentrations in ponds in which bass were stocked at the two densities. These data indicate that largemouth bass of the size used in this study are amenable to pond culture at densities of at least 12,350 fish/ha and that higher stocking densities may be possible. 相似文献
133.
The concentrations of total steroid oestrogen, measured as oestradiol‐17β, in the peripheral plasma of four maturing pullets were determined by radioimmunoassay. The concentrations fluctuated but showed an overall increase to reach maximum values some 2 to 3 weeks before the first egg was laid. 相似文献
134.
135.
Pharyngeal rhabdomyosarcoma in a dog 总被引:1,自引:0,他引:1
136.
137.
Severe granulomatous lesions in cervical muscles and lymph nodes, associated with the use of an oil-based erysipelas vaccine, caused considerable economic loss at slaughter in 1400 pigs from the one herd. The condition was reproduced experimentally using the same vaccine, and in a less severe form with another commercially available oil-based erysipelas vaccine. 相似文献
138.
The spontaneous behaviour and the apparent digestibility of dry matter and fibre and transit times of digesta were compared in four normal horses and four crib-biters. A technique was developed for measuring total gut transit times (TGTT) by using single-stool analysis of the passage of radio-opaque polyethylene markers. Longer TGTT were recorded in the crib-biters than in the normal horses but the orocaecal transit times did not differ. The crib-biters rested less than the normal horses. 相似文献
139.
The Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko), has become a perennial, serious pest of wheat (Triticum aestivum L.) in the western United States. Current methodologies used to enhance RWA resistance in wheat germplasm could benefit from
an understanding of the biochemical mechanisms underlying resistance to RWA. This study was initiated to identify specific
polypeptides induced by RWA feeding that may be associated with RWA resistance. The effects of RWA feeding on PI 140207 (a
RWA-resistant spring wheat) and Pavon (a RWA-susceptible spring wheat) were examined by visualizing, silver-stained denatured
leaf proteins separated by two-dimensional polyacrylamide gel electrophoresis. Comparisons of protein profiles of noninfested
and RWA-infested Pavon and PI 140207 revealed a 24-kilodalton-protein complex selectively inhibited in Pavon that persisted
in PI 140207during RWA attack. No other significant qualitative or quantitative differences were detected in RWA-induced alterations
of protein profiles. These results suggest that RWA feeding selectively inhibit synthesis and accumulation of proteins necessary
for normal metabolic functions in susceptible plants.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
140.