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991.
JH Lin MJ Gunter JE Manson KM Rexrode NR Cook P Kraft BB Cochrane RT Chlebowski GY Ho SM Zhang 《PloS one》2012,7(7):e42079
Background
Estrogen and androgen have been linked to the regulation of circulating hepatocyte growth factor (HGF), an adipose tissue-derived cytokine. It is possible that the CYP19A1 gene which alters sex hormones production may influence HGF levels. We examined the association between the CYP19A1 gene variants and plasma HGF concentrations.Design
We evaluated 45 common and putative functional variants of CYP19A1 and circulating levels of HGF among 260 postmenopausal women who later developed colorectal cancer from the Women''s Health Initiative Observational Cohort. As the distribution of HGF levels was highly skewed, we transformed HGF concentrations for all women into a log-, ranked-, or normal score-scale value. Multiple linear regression with adjustment for age was used to evaluate the associations.Results
We observed an association between the rs7172156, rs1008805, rs6493494, rs749292, and rs11636639 variants and HGF levels in ranked and normal score scales (corrected p values ≤0.02), although the association of these 5 SNPs with log-scale HGF was not significant (corrected p values ≥0.16). The associations remained unchanged after additional adjustment for hormone therapy use and estradiol levels. These 5 SNPs, which were in linkage disequilibrium (pairwise D′≥97%, r2≥56%), constituted a block with 2 common haplotypes accounting for 82% frequency. The most common haplotype, TCCCA, was associated with lower ranked- or normal score-transformed HGF levels (corrected p values ≤0.001), whereas the second most common haplotype, CTTCA, was associated with higher ranked- or normal score-transformed HGF levels (corrected p values ≤0.02).Conclusion
Our findings of a potential association between the CYP19A1 variants and circulating HGF levels warrant confirmation in studies with larger sample size. 相似文献992.
993.
994.
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
995.
Montiel R Solórzano E Díaz N Álvarez-Sandoval BA González-Ruiz M Cañadas MP Simões N Isidro A Malgosa A 《PloS one》2012,7(5):e36371
Ancient DNA (aDNA) analysis can be a useful tool in bacterial disease diagnosis in human remains. However, while the recovery of Mycobacterium spp. has been widely successful, several authors report unsuccessful results regarding ancient treponemal DNA, casting doubts on the usefulness of this technique for the diagnosis of ancient syphilis. Here, we present results from an analysis of four newborn specimens recovered from the crypt of "La Ermita de la Soledad" (XVI-XVII centuries), located in the province of Huelva in the southwest of Spain. We extracted and analyzed aDNA in three independent laboratories, following specific procedures generally practiced in the aDNA field, including cloning of the amplified DNA fragments and sequencing of several clones. This is the most ancient case, reported to date, from which detection of DNA from T. pallidum subspecies pallidum has been successful in more than one individual, and we put forward a hypothesis to explain this result, taking into account the course of the disease in neonate individuals. 相似文献
996.
Chang HH Tai TS Lu B Iannaccone C Cernadas M Weinblatt M Shadick N Miaw SC Ho IC 《PloS one》2012,7(3):e33067
PTPN22 is a tyrosine phosphatase and functions as a damper of TCR signals. A C-to-T single nucleotide polymorphism (SNP) located at position 1858 of human PTPN22 cDNA and converting an arginine (R620) to tryptophan (W620) confers the highest risk of rheumatoid arthritis among non-HLA genetic variations that are known to be associated with this disease. The effect of the R-to-W conversion on the phosphatase activity of PTPN22 protein and the impact of the minor T allele of the C1858T SNP on the activation of T cells has remained controversial. In addition, how the overall activity of PTPN22 is regulated and how the R-to-W conversion contributes to rheumatoid arthritis is still poorly understood. Here we report the identification of an alternative splice form of human PTPN22, namely PTPN22.6. It lacks the nearly entire phosphatase domain and can function as a dominant negative isoform of the full length PTPN22. Although conversion of R620 to W620 in the context of PTPN22.1 attenuated T cell activation, expression of the tryptophan variant of PTPN22.6 reciprocally led to hyperactivation of human T cells. More importantly, the level of PTPN22.6 in peripheral blood correlates with disease activity of rheumatoid arthritis. Our data depict a model that can reconcile the conflicting observations on the functional impact of the C1858T SNP and also suggest that PTPN22.6 is a novel biomarker of rheumatoid arthritis. 相似文献
997.
Creutzfeldt-Jakob disease (CJD) is the most frequent human Prion-related disorder (PrD). The detection of 14-3-3 protein in the cerebrospinal fluid (CSF) is used as a molecular diagnostic criterion for patients clinically compatible with CJD. However, there is a pressing need for the identification of new reliable disease biomarkers. The pathological mechanisms leading to accumulation of 14-3-3 protein in CSF are not fully understood, however neuronal loss followed by cell lysis is assumed to cause the increase in 14-3-3 levels, which also occurs in conditions such as brain ischemia. Here we investigated the relation between the levels of 14-3-3 protein, Lactate dehydrogenase (LDH) activity and expression of the prion protein (PrP) in CSF of sporadic and familial CJD cases. Unexpectedly, we found normal levels of LDH activity in CJD cases with moderate levels of 14-3-3 protein. Increased LDH activity was only observed in a percentage of the CSF samples that also exhibited high 14-3-3 levels. Analysis of the PrP expression pattern in CSF revealed a reduction in PrP levels in all CJD cases, as well as marked changes in its glycosylation pattern. PrP present in CSF of CJD cases was sensitive to proteases. The alterations in PrP expression observed in CJD cases were not detected in other pathologies affecting the nervous system, including cases of dementia and tropical spastic paraparesis/HTLV-1 associated myelopathy (HAM/TSP). Time course analysis in several CJD patients revealed that 14-3-3 levels in CSF are dynamic and show a high degree of variability during the end stage of the disease. Post-mortem analysis of brain tissue also indicated that 14-3-3 protein is upregulated in neuronal cells, suggesting that its expression is modulated during the course of the disease. These results suggest that a combined analysis of 14-3-3 and PrP expression pattern in CSF is a reliable biomarker to confirm the clinical diagnosis of CJD patients and follow disease progression. 相似文献
998.
999.
The origin of litter chemical complexity during decomposition 总被引:4,自引:0,他引:4
The chemical complexity of decomposing plant litter is a central feature shaping the terrestrial carbon (C) cycle, but explanations of the origin of this complexity remain contentious. Here, we ask: How does litter chemistry change during decomposition, and what roles do decomposers play in these changes? During a long‐term (730 days) litter decomposition experiment, we tracked concurrent changes in decomposer community structure and function and litter chemistry using high‐resolution molecular techniques. Contrary to the current paradigm, we found that the chemistry of different litter types diverged, rather than converged, during decomposition due to the activities of decomposers. Furthermore, the same litter type exposed to different decomposer communities exhibited striking differences in chemistry, even after > 90% mass loss. Our results show that during decomposition, decomposer community characteristics regulate changes in litter chemistry, which could influence the functionality of litter‐derived soil organic matter (SOM) and the turnover and stabilisation of soil C. 相似文献
1000.
Nancy E. Gillette E. Matthew Hansen Constance J. Mehmel Sylvia R. Mori Jeffrey N. Webster Nadir Erbilgin David L. Wood 《Agricultural and Forest Entomology》2012,14(4):367-375
- 1 DISRUPT Micro‐Flake Verbenone Bark Beetle Anti‐Aggregant flakes (Hercon Environmental, Inc., Emigsville, Pennsylvania) were applied in two large‐scale tests to assess their efficacy for protecting whitebark pine Pinus albicaulis Engelm. from attack by mountain pine beetle Dendroctonus ponderosae Hopkins (Coleoptera: Scolytinae) (MPB). At two locations, five plots of equivalent size and stand structure served as untreated controls. All plots had early‐ to mid‐outbreak beetle populations (i.e. 7.1–29.2 attacked trees/ha). Verbenone was applied at 370 g/ha in both studies. Intercept traps baited with MPB aggregation pheromone were placed near the corners of each plot after the treatment in order to monitor beetle flight within the plots. Trap catches were collected at 7‐ to 14‐day intervals, and assessments were made at the end of the season of stand structure, stand composition and MPB attack rate for the current and previous years.
- 2 Applications of verbenone flakes significantly reduced the numbers of beetles trapped in treated plots compared with controls at both sites by approximately 50% at the first collection date.
- 3 The applications also significantly reduced the proportion of trees attacked in both Wyoming and Washington using the proportion of trees attacked the previous year as a covariate in the model for analysis of current year attack rates; in both sites, the reduction was ≥ 50%.
- 4 The flake formulation of verbenone appears to have promise for area‐wide treatment by aerial application when aiming to control the mountain pine beetle in whitebark pine forests.