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排序方式: 共有113条查询结果,搜索用时 31 毫秒
61.
Celia Méndez-García Victoria Mesa Richard R Sprenger Michael Richter María Suárez Diez Jennifer Solano Rafael Bargiela Olga V Golyshina ángel Manteca Juan Luis Ramos José R Gallego Irene Llorente Vitor AP Martins dos Santos Ole N Jensen Ana I Peláez Jesús Sánchez Manuel Ferrer 《The ISME journal》2014,8(6):1259-1274
Macroscopic growths at geographically separated acid mine drainages (AMDs) exhibit distinct populations. Yet, local heterogeneities are poorly understood. To gain novel mechanistic insights into this, we used OMICs tools to profile microbial populations coexisting in a single pyrite gallery AMD (pH ∼2) in three distinct compartments: two from a stratified streamer (uppermost oxic and lowermost anoxic sediment-attached strata) and one from a submerged anoxic non-stratified mat biofilm. The communities colonising pyrite and those in the mature formations appear to be populated by the greatest diversity of bacteria and archaea (including ‘ARMAN'' (archaeal Richmond Mine acidophilic nano-organisms)-related), as compared with the known AMD, with ∼44.9% unclassified sequences. We propose that the thick polymeric matrix may provide a safety shield against the prevailing extreme condition and also a massive carbon source, enabling non-typical acidophiles to develop more easily. Only 1 of 39 species were shared, suggesting a high metabolic heterogeneity in local microenvironments, defined by the O2 concentration, spatial location and biofilm architecture. The suboxic mats, compositionally most similar to each other, are more diverse and active for S, CO2, CH4, fatty acid and lipopolysaccharide metabolism. The oxic stratum of the streamer, displaying a higher diversity of the so-called ‘ARMAN''-related Euryarchaeota, shows a higher expression level of proteins involved in signal transduction, cell growth and N, H2, Fe, aromatic amino acids, sphingolipid and peptidoglycan metabolism. Our study is the first to highlight profound taxonomic and functional shifts in single AMD formations, as well as new microbial species and the importance of H2 in acidic suboxic macroscopic growths. 相似文献
62.
63.
The classical concept of linear pathways is being increasingly challenged by network representations, which emphasize the
importance of interactions between components of a biological system, and motivates for adopting a system‐level approach in
biology. We have developed a dynamical system that integrates quantitative, dynamic and topological representation of network of
ERK5 (Extracellular signal‐regulated kinases 5), JNK(c‐Jun N‐terminal kinases) and P38 kinase cascades. We have observered that,
the transient activation of ERK5, JNK1 and P38β kinase, and the persistent activation of JNK2, JNK3 and P38 δ
kinase does not get affected due to the cross‐talks between ERK5, JNK and P38 kinase cascades. But it is due to the cross ‐ talks,
the transiently activated P38α kinase become inactivated, and the transiently activated P38γ kinase become
persistently activated. The impacts of one‐way cross‐talks between the cascades are insignificant and differ from the impact of
two‐way cross‐talks. We generate a hypothesis that, signaling pathways should be studied as a system by considering the
cross‐talks between the two adjacent cascades. 相似文献
64.
Vidhan Jain Henry B Armah Jon E Tongren Renée M Ned Nana O Wilson Sara Crawford Pradeep K Joel Mrigendra P Singh Avinash C Nagpal AP Dash Venkatachalam Udhayakumar Neeru Singh Jonathan K Stiles 《Malaria journal》2008,7(1):1-15
Background
Knowledge on insecticide resistance in target species is a basic requirement to guide insecticide use in malaria control programmes. Malaria transmission in the Mekong region is mainly concentrated in forested areas along the country borders, so that decisions on insecticide use should ideally be made at regional level. Consequently, cross-country monitoring of insecticide resistance is indispensable to acquire comparable baseline data on insecticide resistance.Methods
A network for the monitoring of insecticide resistance, MALVECASIA, was set up in the Mekong region in order to assess the insecticide resistance status of the major malaria vectors in Cambodia, Laos, Thailand, and Vietnam. From 2003 till 2005, bioassays were performed on adult mosquitoes using the standard WHO susceptibility test with diagnostic concentrations of permethrin 0.75% and DDT 4%. Additional tests were done with pyrethroid insecticides applied by the different national malaria control programmes.Results
Anopheles dirus s.s., the main vector in forested malaria foci, was susceptible to permethrin. However, in central Vietnam, it showed possible resistance to type II pyrethroids. In the Mekong delta, Anopheles epiroticus was highly resistant to all pyrethroid insecticides tested. It was susceptible to DDT, except near Ho Chi Minh City where it showed possible DDT resistance. In Vietnam, pyrethroid susceptible and tolerant Anopheles minimus s.l. populations were found, whereas An. minimus s.l. from Cambodia, Laos and Thailand were susceptible. Only two An. minimus s.l. populations showed DDT tolerance. Anopheles vagus was found resistant to DDT and to several pyrethroids in Vietnam and Cambodia.Conclusion
This is the first large scale, cross-country survey of insecticide resistance in Anopheles species in the Mekong Region. A unique baseline data on insecticide resistance for the Mekong region is now available, which enables the follow-up of trends in susceptibility status in the region and which will serve as the basis for further resistance management. Large differences in insecticide resistance status were observed among species and countries. In Vietnam, insecticide resistance was mainly observed in low or transmission-free areas, hence an immediate change of malaria vector control strategy is not required. Though, resistance management is important because the risk of migration of mosquitoes carrying resistance genes from non-endemic to endemic areas. Moreover, trends in resistance status should be carefully monitored and the impact of existing vector control tools on resistant populations should be assessed. 相似文献65.
M Lundervold EJ Milner-Gulland CJ O'Callaghan C Hamblin A Corteyn AP Macmillan 《Acta veterinaria Scandinavica》2004,45(4):211-224
The results of a serological survey of livestock in Kazakhstan, carried out in 1997–1998, are reported. Serum samples from
958 animals (cattle, sheep and goats) were tested for antibodies to foot and mouth disease (FMD), bluetongue (BT), epizootic
haemorrhagic disease (EHD), rinderpest (RP) and peste des petits ruminants (PPR) viruses, and to Brucella spp. We also investigated the vaccination status of livestock and related this to changes in veterinary provision since independence
in 1991. For the 2 diseases under official surveillance (FMD and brucellosis) our results were similar to official data, although
we found significantly higher brucellosis levels in 2 districts and widespread ignorance about FMD vaccination status. The
seroprevalence for BT virus was 23%, and seropositive animals were widespread suggesting endemicity, despite the disease not
having being previously reported. We found a few seropositives for EHDV and PPRV, which may suggest that these diseases are
also present in Kazakhstan. An hierarchical model showed that seroprevalence to FMD and BT viruses were clustered at the farm/village
level, rather than at a larger spatial scale. This was unexpected for FMD, which is subject to vaccination policies which
vary at the raion (county) level. 相似文献
66.
Jordi Corominas Jorge AP Marchesi Anna Puig-Oliveras Manuel Revilla Jordi Estellé Estefania Alves Josep M Folch Maria Ballester 《遗传、选种与进化》2015,47(1)
Background
In previous studies on an Iberian x Landrace cross, we have provided evidence that supported the porcine ELOVL6 gene as the major causative gene of the QTL on pig chromosome 8 for palmitic and palmitoleic acid contents in muscle and backfat. The single nucleotide polymorphism (SNP) ELOVL6:c.-533C > T located in the promoter region of ELOVL6 was found to be highly associated with ELOVL6 expression and, accordingly, with the percentages of palmitic and palmitoleic acids in longissimus dorsi and adipose tissue. The main goal of the current work was to further study the role of ELOVL6 on these traits by analyzing the regulation of the expression of ELOVL6 and the implication of ELOVL6 polymorphisms on meat quality traits in pigs.Results
High-throughput sequencing of BAC clones that contain the porcine ELOVL6 gene coupled to RNAseq data re-analysis showed that two isoforms of this gene are expressed in liver and adipose tissue and that they differ in number of exons and 3’UTR length. Although several SNPs in the 3’UTR of ELOVL6 were associated with palmitic and palmitoleic acid contents, this association was lower than that previously observed with SNP ELOVL6:c.-533C > T. This SNP is in full linkage disequilibrium with SNP ELOVL6:c.-394G > A that was identified in the binding site for estrogen receptor alpha (ERα). Interestingly, the ELOVL6:c.-394G allele is associated with an increase in methylation levels of the ELOVL6 promoter and with a decrease of ELOVL6 expression. Therefore, ERα is clearly a good candidate to explain the regulation of ELOVL6 expression through dynamic epigenetic changes in the binding site of known regulators of ELOVL6 gene, such as SREBF1 and SP1.Conclusions
Our results strongly suggest the ELOVL6:c.-394G > A polymorphism as the causal mutation for the QTL on pig chromosome 8 that affects fatty acid composition in pigs.Electronic supplementary material
The online version of this article (doi:10.1186/s12711-015-0111-y) contains supplementary material, which is available to authorized users. 相似文献67.
GV Pavlova AA Vergun EY Rybalkina PR Butovskaya AP Ryskov 《Cell cycle (Georgetown, Tex.)》2015,14(2):200-205
Random amplified polymorphic DNA (RAPD) analysis was adapted for genomic identification of cell cultures and evaluation of DNA stability in cells of different origin at different culture passages. DNA stability was observed in cultures after no more than 5 passages. Adipose-derived stromal cells demonstrated increased DNA instability. RAPD fragments from different cell lines after different number of passages were cloned and sequenced. The chromosomal localization of these fragments was identified and single-nucleotide variations in RAPD fragments isolated from cell lines after 8–12 passages were revealed. Some of them had permanent localization, while most variations demonstrated random distribution and can be considered as de novo mutations. 相似文献
68.
Sankaranarayanan TM Banu M Pandurangan A Sivasanker S 《Bioresource technology》2011,102(22):10717-10723
Mixtures of sunflower oil and a straight run gas oil in the diesel fuel range were hydroprocessed over sulfided NiO(3%)-MoO3(12%)-γ-Al2O3 incorporating 0, 15 or 30 wt.% zeolite beta (BEA). The studies were carried out at 320-350 °C; 30-60 bars, and weight hourly space velocities (WHSV), 1-4 h(-1). Catalyst containing 30% BEA achieved nearly 100 % conversion of the vegetable oil into hydrocarbons at 330 °C, 60 bars and a WHSV of 2 h(-1) compared to 95.5% by the Ni-Mo-γ-alumina catalyst without BEA. Hydroprocessing with blends containing oleic acid revealed that the catalysts were able to transform the acid into hydrocarbons. An analysis of the ratios of the n-C18 and n-C17 paraffins formed from the vegetable oil at different process conditions revealed that the catalyst containing 15% BEA was most active for hydrodeoxygenation. The gas oil-hydrodesulfurization activity of the Ni-Mo-Al2O3 was enhanced by the addition of BEA by more than 10%. 相似文献
69.
David Lee Tjaart AP de Beer Roman A Laskowski Janet M Thornton Christine A Orengo 《BMC structural biology》2011,11(1):2
Background
The Midwest Center for Structural Genomics (MCSG) is one of the large-scale centres of the Protein Structure Initiative (PSI). During the first two phases of the PSI the MCSG has solved over a thousand protein structures. A criticism of structural genomics is that target selection strategies mean that some structures are solved without having a known function and thus are of little biomedical significance. Structures of unknown function have stimulated the development of methods for function prediction from structure. 相似文献70.
Sambandam Ravikumar Sivalingam Shyamala Pandurangan Muthuraman 《Preparative biochemistry & biotechnology》2013,43(2):122-137
A thermostable isoenzyme (T80) of xylose isomerase from the eukaryote xerophyte Cereus pterogonus was purified to homogeneity by precipitation with ammonium sulfate and column chromatography on Dowex-1 ion exchange, with Sephadex G-100 gel filtration, resulting in an approximately 25.55-fold increase in specific activity and a final yield of approximately 17.9%. Certain physiochemical and kinetic properties (Km and Vmax) of the T80 xylose isomerase isoenzyme were investigated. The molecular mass of the purified T80 isoenzyme was 68 kD determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Polyclonal antibodies against the purified T80 isoenzyme recognized a single polypeptide band on Western blots. The activation energy required for the thermal denaturation of the isoenzyme was determined to be 61.84 KJ mol?1. The use of differential scanning calorimetry established the melting temperature of the CPXI isoenzyme to be 80°C, but when studied with added metal ions, melting temperature increases to more than the normal. Fluorescence spectroscopy of T80 isoenzymes yielded an emission peak with λem at 320 nm and 340 nm, respectively, confirming the presence of Trp residue in these proteins. Electron paramagnetic resonance (EPR) analysis at liquid nitrogen temperature established the presence of Mn2+ and Co2+ associated with each isoenzyme. These enzyme species exhibited different thermal and pH stabilities compared to their mesophilic counterparts and offered greater efficiency in functioning as a potential alternate catalytic converter of glucose in the production of high-fructose corn syrup (HFCS) for the sweetener industry and for ethanol production. 相似文献