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排序方式: 共有160条查询结果,搜索用时 609 毫秒
31.
Distinctive gut microbiota of honey bees assessed using deep sampling from individual worker bees 总被引:2,自引:0,他引:2
Surveys of 16S rDNA sequences from the honey bee, Apis mellifera, have revealed the presence of eight distinctive bacterial phylotypes in intestinal tracts of adult worker bees. Because previous studies have been limited to relatively few sequences from samples pooled from multiple hosts, the extent of variation in this microbiota among individuals within and between colonies and locations has been unclear. We surveyed the gut microbiota of 40 individual workers from two sites, Arizona and Maryland USA, sampling four colonies per site. Universal primers were used to amplify regions of 16S ribosomal RNA genes, and amplicons were sequenced using 454 pyrotag methods, enabling analysis of about 330,000 bacterial reads. Over 99% of these sequences belonged to clusters for which the first blastn hits in GenBank were members of the known bee phylotypes. Four phylotypes, one within Gammaproteobacteria (corresponding to "Candidatus Gilliamella apicola") one within Betaproteobacteria ("Candidatus Snodgrassella alvi"), and two within Lactobacillus, were present in every bee, though their frequencies varied. The same typical bacterial phylotypes were present in all colonies and at both sites. Community profiles differed significantly among colonies and between sites, mostly due to the presence in some Arizona colonies of two species of Enterobacteriaceae not retrieved previously from bees. Analysis of Sanger sequences of rRNA of the Snodgrassella and Gilliamella phylotypes revealed that single bees contain numerous distinct strains of each phylotype. Strains showed some differentiation between localities, especially for the Snodgrassella phylotype. 相似文献
33.
Daw-Yang Hwang Stefan Kohl Xueping Fan Asaf Vivante Stefanie Chan Gabriel C. Dworschak Julian Schulz Albertien M. van Eerde Alina C. Hilger Heon Yung Gee Tracie Pennimpede Bernhard G. Herrmann Glenn van de Hoek Kirsten Y. Renkema Christoph Schell Tobias B. Huber Heiko M. Reutter Neveen A. Soliman Natasa Stajic Radovan Bogdanovic Elijah O. Kehinde Richard P. Lifton Velibor Tasic Weining Lu Friedhelm Hildebrandt 《Human genetics》2015,134(8):905-916
34.
Helen J. Mosson Elaine H. Richards Gay C. Marris John P. Edwards 《Physiological Entomology》2000,25(3):296-302
Serum from larvae of Lacanobia oleracea L. (Lepidoptera; Noctuidae) parasitized by Eulophus pennicornis (Hymenoptera; Eulophidae) and from normal non‐parasitized larvae is capable of agglutinating rabbit, sheep, calf, goat, chicken, horse and human erythrocytes, but not yeast. Studies with a range of inhibitory carbohydrates showed that serum lectins(s) had specificity for sugars containing galactose and for rhamnose, and for the glycosubstances fetuin and asialofetuin. Lectin activity is heat‐labile and is not dependent on calcium. Parasitism by E. pennicornis caused an increase in the agglutination titre of the serum from larvae of L. oleracea but not an increase in specific activity (titre per mg protein per ml). However, when venom from the venom gland of female wasps was injected into L. oleracea larvae, both the agglutinating activity and the specific activity of the larval serum increased. The possible causes of this increase are discussed. It is suggested that venom contains antigenic components which, when injected into the haemocoel of the L. oleracea larva, may be increasing lectin synthesis and/or release into the serum. 相似文献
35.
Good knowledge on the interactions between climatic variables and malaria can be very useful for predicting outbreaks and preparedness interventions. We investigated clinical malaria transmission patterns and its temporal relationship with climatic variables in Tubu village, Botswana. A 5-year retrospective time series data analysis was conducted to determine the transmission patterns of clinical malaria cases at Tubu Health Post and its relationship with rainfall, flood discharge, flood extent, mean minimum, maximum and average temperatures. Data was obtained from clinical records and respective institutions for the period July 2005 to June 2010, presented graphically and analysed using the Univariate ANOVA and Pearson cross-correlation coefficient tests. Peak malaria season occurred between October and May with the highest cumulative incidence of clinical malaria cases being recorded in February. Most of the cases were individuals aged >5 years. Associations between the incidence of clinical malaria cases and several factors were strong at lag periods of 1 month; rainfall (r = 0.417), mean minimum temperature (r = 0.537), mean average temperature (r = 0.493); and at lag period of 6 months for flood extent (r = 0.467) and zero month for flood discharge (r = 0.497). The effect of mean maximum temperature was strongest at 2-month lag period (r = 0.328). Although malaria transmission patterns varied from year to year the trends were similar to those observed in sub-Saharan Africa. Age group >5 years experienced the greatest burden of clinical malaria probably due to the effects of the national malaria elimination programme. Rainfall, flood discharge and extent, mean minimum and mean average temperatures showed some correlation with the incidence of clinical malaria cases. 相似文献
36.
37.
Tumor suppressor Tsc1 is a new Hsp90 co‐chaperone that facilitates folding of kinase and non‐kinase clients 下载免费PDF全文
Elijah Marris Diana M Dunn Adam R Blanden Ryan L Murphy Nicholas Rensing Oleg Shapiro Barry Panaretou Chrisostomos Prodromou Stewart N Loh David H Gutmann Dimitra Bourboulia Gennady Bratslavsky Michael Wong Mehdi Mollapour 《The EMBO journal》2017,36(24):3650-3665
The tumor suppressors Tsc1 and Tsc2 form the tuberous sclerosis complex (TSC), a regulator of mTOR activity. Tsc1 stabilizes Tsc2; however, the precise mechanism involved remains elusive. The molecular chaperone heat‐shock protein 90 (Hsp90) is an essential component of the cellular homeostatic machinery in eukaryotes. Here, we show that Tsc1 is a new co‐chaperone for Hsp90 that inhibits its ATPase activity. The C‐terminal domain of Tsc1 (998–1,164 aa) forms a homodimer and binds to both protomers of the Hsp90 middle domain. This ensures inhibition of both subunits of the Hsp90 dimer and prevents the activating co‐chaperone Aha1 from binding the middle domain of Hsp90. Conversely, phosphorylation of Aha1‐Y223 increases its affinity for Hsp90 and displaces Tsc1, thereby providing a mechanism for equilibrium between binding of these two co‐chaperones to Hsp90. Our findings establish an active role for Tsc1 as a facilitator of Hsp90‐mediated folding of kinase and non‐kinase clients—including Tsc2—thereby preventing their ubiquitination and proteasomal degradation. 相似文献
38.
S. Hodge N. Curtis C. J. Vink J. Marris S. D. J. Brown 《Arthropod-Plant Interactions》2017,11(5):691-701
When studying arthropod visitors of flowers, the sampling unit (individual flowers, groups of flowers, areas of plants, timed visits, etc.) depends upon the aim of the study and the sampling method employed. In this study, arthropods using flowers of the ice plant, Carpobrotus edulis, were recorded on the sand dunes at New Brighton in the south island of New Zealand. Of 3600 flowers, only 10% contained invertebrates and only 478 specimens were recorded in total. Of 32 arthropod species observed on this exotic plant, we consider at least 20 to be native to New Zealand and five species are probably New Zealand endemics. Based on an occupation rate of individual flowers of 10%, a binomial model indicated that a sample of 100 flowers would have <0.003% chance of containing no specimens, and 96% chance that 5–16 flowers would contain some animals. Species accumulation models (e.g. bootstrap, Chao and rarefaction) and models examining the likelihood of recording rare species indicated that after examining 2000 flowers, 80% of arthropod species would be recorded, and that only the rarest species in our study would fall below an 80% statistical power of detection. The results suggest that for this flower–invertebrate system, a scheme that involved 20 independent samples, each consisting of 100 flowers, would provide a good chance of (1) avoiding totally empty samples (2) collecting a high proportion of the total species present and (3) recording all but the very rarest species that occur in this system. 相似文献
39.
Suppression of proliferative defects associated with processing-defective lamin A mutants by hTERT or inactivation of p53 总被引:1,自引:0,他引:1
Kudlow BA Stanfel MN Burtner CR Johnston ED Kennedy BK 《Molecular biology of the cell》2008,19(12):5238-5248
Hutchinson-Gilford progeria syndrome (HGPS) is a rare, debilitating disease with early mortality and rapid onset of aging-associated pathologies. It is linked to mutations in LMNA, which encodes A-type nuclear lamins. The most frequent HGPS-associated LMNA mutation results in a protein, termed progerin, with an internal 50 amino acid deletion and, unlike normal A-type lamins, stable farnesylation. The cellular consequences of progerin expression underlying the HGPS phenotype remain poorly understood. Here, we stably expressed lamin A mutants, including progerin, in otherwise identical primary human fibroblasts to compare the effects of different mutants on nuclear morphology and cell proliferation. We find that expression of progerin leads to inhibition of proliferation in a high percentage of cells and slightly premature senescence in the population. Expression of a stably farnesylated mutant of lamin A phenocopied the immediate proliferative defects but did not result in premature senescence. Either p53 inhibition or, more surprisingly, expression of the catalytic subunit of telomerase (hTERT) suppressed the early proliferative defects associated with progerin expression. These findings lead us to propose that progerin may interfere with telomere structure or metabolism in a manner suppressible by increased telomerase levels and possibly link mechanisms leading to progeroid phenotypes to those of cell immortalization. 相似文献
40.
Gilaad G. Kaplan Elijah Dixon Remo Panaccione Andrew Fong Li Chen Mieczyslaw Szyszkowicz Amanda Wheeler Anthony MacLean W. Donald Buie Terry Leung Steven J. Heitman Paul J. Villeneuve 《CMAJ》2009,181(9):591-597