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Cap liners were found to be a major source of plasticizer contamination of high-purity extraction solvents. Plasticizer concentrations found ranged from 0.1–5 ppm; this can produce substantial interference in biological analysis because of the rather high concentration factors obtained in the final extracts. 相似文献
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KR N’Guessan BRD Aboua J Tison-Rosebery A Ouattara EP Kouamelan 《African Journal of Aquatic Science》2018,43(2):131-140
The ecology and taxonomy of the epilithic diatom flora of the Agnéby River, Ivory Coast were studied in 2012. Ten sites were investigated and diatoms were sampled on glass slides immersed for a period of 30 days during the wet and dry seasons. Physico-chemical parameters were measured at each site while sampling diatoms. Five taxa were largely dominant: Planothidium comperei CE Wetzel, N’Guessan and Tison-Rosebery, Eolimna minima (Grunow) Lange-Bertalot, Planothidium piaficum (JR Carter and Denny) CE Wetzel and Ector, Cocconeis schroederi Foged and Cocconeis scutellum var. parva (Grunow in Van Heurck) Cleve. Electrical conductivity, temperature, dissolved oxygen, nitrite and phosphorus were found to influence the distribution of taxa. 相似文献
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Maureen A Sartor Dana C Dolinoy Tamara R Jones Justin A Colacino Mark EP Prince Thomas E Carey Laura S Rozek 《Epigenetics》2011,6(6):777-787
Oncogenic human papillomaviruses (HPV) are associated with nearly all cervical cancers and are increasingly important in the etiology of oropharyngeal tumors. HPV-associated head and neck squamous cell carcinomas (HNSCC) have distinct risk profiles and appreciate a prognostic advantage compared to HPV-negative HNSCC. Promoter hypermethylation is widely recognized as a mechanism in the progression of HNSCC, but the extent to which this mechanism is consistent between HPV(+) and HPV(−) tumors is unknown. To investigate the epigenetic regulation of gene expression in HPV-induced and carcinogen-induced cancers, we examined genome-wide DNA methylation and gene expression in HPV(+) and HPV(−) SCC cell lines. We used two platforms: the Illumina Infinium Methylation BeadArray and tiling arrays, and confirmed illustrative examples with pyrosequencing and quantitative PCR. These analyses indicate that HPV(+) cell lines have higher DNA methylation in genic and LINE-1 regions than HPV(−) cell lines. Differentially methylated loci between HPV(+) and HPV(−) cell lines significantly correlated with HPV-typed HNSCC primary tumor DNA methylation levels. Novel findings include higher promoter methylation of polycomb repressive complex 2 target genes in HPV(+) cells compared to HPV(−) cells and increased expression of DNMT3A in HPV(+) cells. Additionally, CDKN2A and KRT8 were identified as interaction hubs among genes with higher methylation and lower expression in HPV(−) cells. Conversely, RUNX2, IRS-1 and CCNA1 were major hubs with higher methylation and lower expression in HPV(+) cells. Distinct HPV(+) and HPV(−) epigenetic profiles should provide clues to novel targets for development of individualized therapeutic strategies.Key words: epigenetics, human papillomavirus, HNSCC, DNA methylation, squamous cell carcinoma, gene expression, microarrays, illumina infinium humanmethylation27 beadarray 相似文献
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Fellow travellers: a concordance of colonization patterns between mice and men in the North Atlantic region 总被引:1,自引:0,他引:1
EP Jones K Skirnisson TH McGovern MTP Gilbert E Willerslev JB Searle 《BMC evolutionary biology》2012,12(1):1-8
Background
In the Calvin cycle of eubacteria, the dephosphorylations of both fructose-1, 6-bisphosphate (FBP) and sedoheptulose-1, 7-bisphosphate (SBP) are catalyzed by the same bifunctional enzyme: fructose-1, 6-bisphosphatase/sedoheptulose-1, 7-bisphosphatase (F/SBPase), while in that of eukaryotic chloroplasts by two distinct enzymes: chloroplastic fructose-1, 6-bisphosphatase (FBPase) and sedoheptulose-1, 7-bisphosphatase (SBPase), respectively. It was proposed that these two eukaryotic enzymes arose from the divergence of a common ancestral eubacterial bifunctional F/SBPase of mitochondrial origin. However, no specific affinity between SBPase and eubacterial FBPase or F/SBPase can be observed in the previous phylogenetic analyses, and it is hard to explain why SBPase and/or F/SBPase are/is absent from most extant nonphotosynthetic eukaryotes according to this scenario.Results
Domain analysis indicated that eubacterial F/SBPase of two different resources contain distinct domains: proteobacterial F/SBPases contain typical FBPase domain, while cyanobacterial F/SBPases possess FBPase_glpX domain. Therefore, like prokaryotic FBPase, eubacterial F/SBPase can also be divided into two evolutionarily distant classes (Class I and II). Phylogenetic analysis based on a much larger taxonomic sampling than previous work revealed that all eukaryotic SBPase cluster together and form a close sister group to the clade of epsilon-proteobacterial Class I FBPase which are gluconeogenesis-specific enzymes, while all eukaryotic chloroplast FBPase group together with eukaryotic cytosolic FBPase and form another distinct clade which then groups with the Class I FBPase of diverse eubacteria. Motif analysis of these enzymes also supports these phylogenetic correlations.Conclusions
There are two evolutionarily distant classes of eubacterial bifunctional F/SBPase. Eukaryotic FBPase and SBPase do not diverge from either of them but have two independent origins: SBPase share a common ancestor with the gluconeogenesis-specific Class I FBPase of epsilon-proteobacteria (or probably originated from that of the ancestor of epsilon-proteobacteria), while FBPase arise from Class I FBPase of an unknown kind of eubacteria. During the evolution of SBPase from eubacterial Class I FBPase, the SBP-dephosphorylation activity was acquired through the transition ??from specialist to generalist??. The evolutionary substitution of the endosymbiotic-origin cyanobacterial bifunctional F/SBPase by the two light-regulated substrate-specific enzymes made the regulation of the Calvin cycle more delicate, which contributed to the evolution of eukaryotic photosynthesis and even the entire photosynthetic eukaryotes. 相似文献29.
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