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排序方式: 共有103条查询结果,搜索用时 15 毫秒
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The Anti-Endotoxin Activity of Taurolin in Experimental Animals 总被引:2,自引:1,他引:1
Taurolin, a broad spectrum bactericidal agent, protected experimental animals from the lethal effects of Escherichia coli and Bacteroides fragilis endotoxin. Taurolin also prevented the pyrexic response of rabbits to TAB vaccine. Results suggest that Taurolin exerts its antiendotoxic effect by direct reaction with the endotoxin molecule. 相似文献
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Rabbit burrows in three different habitats in an arid area showed characteristic variations and differences. Burrows in stony soil were generally cooler and more humid than burrows in sand and gravel soil. The temperature of the burrows in sand and gravel showed similar characteristics but the humidity in the gravel burrows was almost always significantly less than that of the sand burrows. Air and ground temperatures were significantly correlated but air and ground humidities showed a less significant correlation. Seasonal differences in microclimate within and between the three types of burrows were pronounced and are thought to cause differences in the survival of rabbits in arid areas. 相似文献
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ANNE-LISE VARNIER LISA SANCHEZ PARUL VATSA LESLIE BOUDESOCQUE ANGELA GARCIA-BRUGGER FANJA RABENOELINA ALEXANDER SOROKIN JEAN-HUGUES RENAULT SERGE KAUFFMANN ALAIN PUGIN CHRISTOPHE CLEMENT FABIENNE BAILLIEUL & STEPHAN DOREY 《Plant, cell & environment》2009,32(2):178-193
Rhamnolipids produced by the bacteria Pseudomonas aeruginosa are known as very efficient biosurfactant molecules. They are used for a wide range of industrial applications, especially in food, cosmetics and pharmaceutical formulations as well as in bioremediation of pollutants. In this paper, the role of rhamnolipids as novel molecules triggering defence responses and protection against the fungus Botrytis cinerea in grapevine is presented. The effect of rhamnolipids was assessed in grapevine using cell suspension cultures and vitro-plantlets. Ca2+ influx, mitogen-activated protein kinase activation and reactive oxygen species production form part of early signalling events leading from perception of rhamnolipids to the induction of plant defences that include expression of a wide range of defence genes and a hypersensitive response (HR)-like response. In addition, rhamnolipids potentiated defence responses induced by the chitosan elicitor and by the culture filtrate of B. cinerea . We also demonstrated that rhamnolipids have direct antifungal properties by inhibiting spore germination and mycelium growth of B. cinerea . Ultimately, rhamnolipids efficiently protected grapevine against the fungus. We propose that rhamnolipids are acting as microbe-associated molecular patterns (MAMPs) in grapevine and that the combination of rhamnolipid effects could participate in grapevine protection against grey mould disease. 相似文献
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Abstract: Complete skulls of giant marine reptiles of the Late Jurassic are rare, and so the discovery of the 1.8‐m‐long skull of a pliosaur from the Kimmeridge Clay Formation (Kimmeridgian) of Westbury, Wiltshire, UK, is an important find. The specimen shows most of the cranial and mandibular anatomy, as well as a series of pathological conditions. It was previously referred to Pliosaurus brachyspondylus, but it can be referred reliably only to the genus Pliosaurus, because species within the genus are currently in need of review. The new specimen, together with another from the same locality, also referred to P. brachyspondylus, will be crucial in that systematic revision, and it is likely that the genus Pliosaurus will be found to include several genera. The two Westbury Pliosaurus specimens share many features, including the form of the teeth, but marked differences in the snout and parietal crest suggest sexual dimorphism; the present specimen is probably female. The large size of the animal, the extent of sutural fusion and the pathologies suggest this is an ageing individual. An erosive arthrotic condition of the articular glenoids led to prolonged jaw misalignment, generating a suite of associated bone and dental pathologies. Further damage to the jaw joint may have been the cause of death. 相似文献
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DAVID M. LESLIE JR. R. TERRY BOWYER JONATHAN A. JENKS 《The Journal of wildlife management》2008,72(6):1420-1433
Abstract: Fecal nitrogen (FN) has been applied widely as an index of dietary quality in studies of nutritional ecology of free-ranging and captive vertebrate herbivores, particularly ruminants. Three related articles in the Journal of Wildlife Management (JWM; Leslie and Starkey 1985, 1987; Hobbs 1987) have been cited (n = 150) in 87 publications and 39 peer-reviewed journals. The critique by Hobbs (1987) and the reply by Leslie and Starkey (1987) on limitations and appropriate applications of FN have been used to justify use of FN or negate its value as a nutritional proxy. We undertook a retrospective analysis of FN applications since 1985, largely because we sensed that methodological cautions noted in the 3 JWM publications were not being followed, leading to faulty conclusions and management applications, and that application protocols needed updating. From January 1986 through July 2007, the 107 species-by-continent applications of FN, citing the 3 JWM publications singly or in any combination, were diverse; FN was used in various ways on 5 continents and for 50 wild and domestic species. Cumulative rates of departure from recommended FN applications increased in recent years, largely in studies that compare different species while failing to fully acknowledge that differences likely reflected digestive capabilities rather than differences in some aspect of dietary intake. Post-1985 research on plant secondary compounds (e.g., tannins) has refined limitations to the application of FN, permitting more straightforward protocols than were possible in 1985. Although use does not necessarily reflect value, the number of published applications during the past 22 years indicates that peer reviewers from a variety of scientific disciplines view FN as a suitable proxy for nutritional status, which can be used to contrast study units when carefully defined by the study design. Any index can have shortcomings, and there are still circumstances when application of FN is problematic. Precise prediction of intake with FN under field conditions is still hampered by inherent variability, but contrasts of comparable study units and species can be appropriate. Published protocols for FN, as amended herein, should be adhered to, and conclusions are strengthened by the use of multiple nutritional indices. 相似文献
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JAMES R. ALLEN LESLIE E. MCINENLY EVELYN H. MERRILL MARK S. BOYCE 《The Journal of wildlife management》2008,72(8):1798-1804
Abstract: Stratification is commonly used to improve sampling efficiency of aerial surveys of ungulate populations with strata typically based on a priori information, such as preflight animal observations or vegetation attributes as surrogates for animal densities. We evaluated the usefulness of stratifying survey units for elk (Cervus elaphus) in the Rocky Mountain foothills of Alberta, Canada, using a resource selection function (RSF). We compared precision and design efficiency (DEFF) of population estimates from stratification approaches based on an RSF model to the past approach using amount of forest cover. We used a sample of telemetry relocations taken over a 3-year period from 165 elk, rarified to times of the day and months of the year when aerial surveys are conducted, to develop the RSF. We then used the top RSF model, based on Akaike's Information Criterion, to derive the average RSF value for an 8-km2 survey unit. Using survey data from the first year, we evaluated binning schemes to define RSF-oriented strata based on poststratification and showed that Jenks natural breaks in the RSF values provided the greatest improvement in DEFF and increased precision, compared to 2 other stratification schemes. We then used this approach with data from 2 additional surveys to find that stratification by RSF consistently improves relative precision and design efficiency of elk population estimates, whether we employ pre- or poststratification. Where a RSF is available it could be used as a surrogate for animal densities when conducting stratified sampling for population surveys. 相似文献
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VESSEY J KEVIN; RAPER C DAVID JR; HENRY LESLIE TOLLEY 《Journal of experimental botany》1990,41(12):1579-1584
Net uptake of by non-nodulated soybean plants [Glycme max(L ) Merr cv Ransom] growing in flowing hydroponicculture was measured daily during a 63 d period of reproductivedevelopment between the first florally inductive photopenodand late seed growth Removal of from a replenished solution containing 10 mol m was determined by ion chromatography Uptake of continued throughout reproductive development The net uptakerate of cycled between maxima and minima with a periodicity of oscillation of 3 to 7 d during the floralstage and about 6 d during the fruiting stage. Coupled withincreasing concentrations of carbon and C:N ratios in tissues,the oscillations in net uptake rates of are evidence that the demand for carbohydrate by reproductiveorgans is contingent on the availability of nitrogen in theshoot pool rather than that the demand for nitrogen followsthe flux of carbohydrate into reproductive tissues. Key words: Nitrate uptake rate, carbon-nitrogen partitioning, Glycme max (L ) Merrill 相似文献