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排序方式: 共有76条查询结果,搜索用时 15 毫秒
41.
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
42.
43.
Flávia C Rodrigues-Lisoni Paulo PeitlJr Alessandra Vidotto Giovana M Polachini José V Maniglia Juliana Carmona-Raphe Bianca R Cunha Tiago Henrique Caique F Souza Rodrigo AP Teixeira Erica E Fukuyama Pedro MichaluartJr Marcos B de Carvalho Sonia M Oliani Head Neck Genome Project GENCAPO Eloiza H Tajara 《BMC medical genomics》2010,3(1):14
Background
The development and progression of cancer depend on its genetic characteristics as well as on the interactions with its microenvironment. Understanding these interactions may contribute to diagnostic and prognostic evaluations and to the development of new cancer therapies. Aiming to investigate potential mechanisms by which the tumor microenvironment might contribute to a cancer phenotype, we evaluated soluble paracrine factors produced by stromal and neoplastic cells which may influence proliferation and gene and protein expression.Methods
The study was carried out on the epithelial cancer cell line (Hep-2) and fibroblasts isolated from a primary oral cancer. We combined a conditioned-medium technique with subtraction hybridization approach, quantitative PCR and proteomics, in order to evaluate gene and protein expression influenced by soluble paracrine factors produced by stromal and neoplastic cells.Results
We observed that conditioned medium from fibroblast cultures (FCM) inhibited proliferation and induced apoptosis in Hep-2 cells. In neoplastic cells, 41 genes and 5 proteins exhibited changes in expression levels in response to FCM and, in fibroblasts, 17 genes and 2 proteins showed down-regulation in response to conditioned medium from Hep-2 cells (HCM). Nine genes were selected and the expression results of 6 down-regulated genes (ARID4A, CALR, GNB2L1, RNF10, SQSTM1, USP9X) were validated by real time PCR.Conclusions
A significant and common denominator in the results was the potential induction of signaling changes associated with immune or inflammatory response in the absence of a specific protein.44.
S Çolakoğlu A Aktaş S Raimondo AP Türkmen BZ Altunkaynak E Odacı 《Biotechnic & histochemistry》2014,89(2):136-144
We investigated the effects of diclofenac sodium (DS) on development of the optic nerve in utero. Pregnant female rats were separated into three groups: control, saline treated and DS treated. Offspring of these animals were divided into 4-week-old and 20-week-old groups. At the end of the 4th and 20th weeks of postnatal life, the animals were sacrificed, and right optic nerves were excised and sectioned for ultrastructural and stereological analyses. We demonstrated that both DS and saline produced structural and morphometric changes in the total axon number and density of axons, but decreased the myelin sheath thickness in male optic nerves. All ultrastructural and morphometric features were well developed in 20-week-old rats. We showed that development of the optic nerve continues during the early postnatal period and that some compensation for exposure to deleterious agents in utero may occur during early postnatal life. 相似文献
45.
Network analysis of temporal functionalities of the gut induced by perturbations in new-born piglets
Nirupama Benis Dirkjan Schokker Maria Suarez-Diez Vitor AP Martins dos Santos Hauke Smidt Mari A Smits 《BMC genomics》2015,16(1)
Background
Evidence is accumulating that perturbation of early life microbial colonization of the gut induces long-lasting adverse health effects in individuals. Understanding the mechanisms behind these effects will facilitate modulation of intestinal health. The objective of this study was to identify biological processes involved in these long lasting effects and the (molecular) factors that regulate them. We used an antibiotic and the same antibiotic in combination with stress on piglets as an early life perturbation. Then we used host gene expression data from the gut (jejunum) tissue and community-scale analysis of gut microbiota from the same location of the gut, at three different time-points to gauge the reaction to the perturbation. We analysed the data by a new combination of existing tools. First, we analysed the data in two dimensions, treatment and time, with quadratic regression analysis. Then we applied network-based data integration approaches to find correlations between host gene expression and the resident microbial species.Results
The use of a new combination of data analysis tools allowed us to identify significant long-lasting differences in jejunal gene expression patterns resulting from the early life perturbations. In addition, we were able to identify potential key gene regulators (hubs) for these long-lasting effects. Furthermore, data integration also showed that there are a handful of bacterial groups that were associated with temporal changes in gene expression.Conclusion
The applied systems-biology approach allowed us to take the first steps in unravelling biological processes involved in long lasting effects in the gut due to early life perturbations. The observed data are consistent with the hypothesis that these long lasting effects are due to differences in the programming of the gut immune system as induced by the temporary early life changes in the composition and/or diversity of microbiota in the gut.Electronic supplementary material
The online version of this article (doi:10.1186/s12864-015-1733-8) contains supplementary material, which is available to authorized users. 相似文献46.
Engelmann M Wolf G Putzke J Bloom FE Raber J Landgraf R Spina MG Horn TF 《Amino acids》2004,26(1):37-43
Summary. Neurons of the hypothalamo-neurohypophyseal system (HNS) are known to contain high amounts of neuronal nitric oxide (NO) synthase (nNOS). NO produced by those neurons is commonly supposed to be involved as modulator in the release of the two nonapeptides vasopressin (AVP) and oxytocin into the blood stream. Previous studies showed that forced swimming fails to increase the release of AVP into the blood stream while its secretion into the hypothalamus is triggered. We investigated here whether hypothalamically acting NO contributes to the control of the AVP release into blood under forced swimming conditions. Intracerebral microdialysis and in situ hybridization were employed to analyze the activity of the nitrergic system within the supraoptic nucleus (SON), the hypothalamic origin of the HNS. A 10-min forced swimming session failed to significantly alter the local NO release as indicated both by nitrite and, the main by-product of NO synthesis, citrulline levels in microdialysis samples collected from the SON. Microdialysis administration of NO directly into the SON increased the concentration of AVP in plasma samples collected during simultaneous forced swimming. In an additional experiment the effect of the defined stressor exposure on the concentration of mRNA coding for nNOS within the SON was investigated by in situ hybridization. Forced swimming increased the expression of nNOS mRNA at two and four hours after onset of the stressor compared to untreated controls. Taken together, our results imply that NO within the SON does not contribute to the regulation of the secretory activity of HNS neurons during acute forced swimming. Increased nNOS mRNA in the SON after forced swimming and the increase in AVP release in the presence of exogenous NO under forced swimming points to a possible role of NO in the regulation of the HNS under repeated stressor exposure.Current address: Departments of Behavioral Neuroscience and Neurology, Oregon Health & Science University, Portland, OR 97239, U.S.A. 相似文献
47.
Putzke C Hanley PJ Schlichthörl G Preisig-Müller R Rinné S Anetseder M Eckenhoff R Berkowitz C Vassiliou T Wulf H Eberhart L 《American journal of physiology. Cell physiology》2007,293(4):C1319-C1326
Volatile anesthetics have been shown to activate various two-pore (2P) domain K+ (K2P) channels such as TASK-1 and TREK-1 (TWIK-related acid-sensitive K+ channel), and mice deficient in these channels are resistant to halothane-induced anesthesia. Here, we investigated whether K2P channels were also potentially important targets of intravenous anesthetics. Whole cell patch-clamp techniques were used to determine the effects of the commonly used intravenous anesthetics etomidate and propofol on the acid-sensitive K+ current in rat ventricular myocytes (which strongly express TASK-1) and selected human K2P channels expressed in Xenopus laevis oocytes. In myocytes, etomidate decreased both inward rectifier K+ (Kir) current (IK1) and acid-sensitive outward K+ current at positive potentials, suggesting that this drug may inhibit TASK channels. Indeed, in addition to inhibiting guinea pig Kir2.1 expressed in oocytes, etomidate inhibited human TASK-1 (and TASK-3) in a concentration-dependent fashion. Propofol had no effect on human TASK-1 (or TASK-3) expressed in oocytes. Moreover, we showed that, similar to the known effect of halothane, sevoflurane and the purified R-(–)- and S-(+)-enantiomers of isoflurane, without stereoselectivity, activated human TASK-1. We conclude that intravenous and volatile anesthetics have dissimilar effects on K2P channels. Human TASK-1 (and TASK-3) are insensitive to propofol but are inhibited by supraclinical concentrations of etomidate. In contrast, stimulatory effects of sevoflurane and enantiomeric isoflurane on human TASK-1 can be observed at clinically relevant concentrations. volatile anesthetics; etomidate; propofol; ion channels 相似文献
48.
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49.
Protein evolution in different cellular environments: cytochrome b in sharks and mammals 总被引:4,自引:0,他引:4
DNA sequences for the mitochondrial cytochrome b gene were determined for
13 species of sharks. Rates and patterns of amino acid replacement are
compared for sharks and mammals. Absolute rates of cytochrome b evolution
are six times slower in sharks than in mammals. Bivariate plots of the
number of nonsynonymous and silent transversions are indistinguishable in
the two groups, however, suggesting that the differences in amino acid
replacement rates are due primarily to differences in DNA substitution
rates. Patterns of amino acid replacement are also similar in the two
groups. Conserved and variable regions occur in the same parts of the
cytochrome b gene, and there is little evidence that the types of amino
acid changes are significantly different between the groups. Similarity in
the relative rates and patterns of protein change between the two groups
prevails despite dramatic differences in the cellular environments of
sharks and mammals. Poor penetrance of physiological differences through to
rates of protein evolution provides support for the neutral theory and
suggests that, for cytochrome b, patterns of evolution have been relatively
constant throughout much of vertebrate history.
相似文献
50.
Distribution of the molossinus allele of Sry, the testis-determining gene, in wild mice 总被引:3,自引:0,他引:3
Nagamine CM; Shiroishi T; Miyashita N; Tsuchiya K; Ikeda H; Takao N; Wu XL; Jin ML; Wang FS; Kryukov AP 《Molecular biology and evolution》1994,11(6):864-874
When the Y chromosome of the laboratory inbred mouse strain C57BL/6 (B6) is
replaced by the Y of certain strains of Mus musculus domesticus, testis
determination fails and all XY fetuses develop either as hermaphrodites or
XY females (XY sex reversal). This suggests the presence of at least two
alleles of Sry, the male-determining gene on the Y:M. m. domesticus and B6.
The B6 Y chromosome is derived from the Japanese house mouse, M. m.
molossinus and therefore carries a molossinus Sry allele. As a first step
to determine how the molossinus Sry allele evolved, its distribution
pattern was determined in wild mice. The cumulative data of 96 M. musculus
samples obtained from 58 geographical locations in Europe, North Africa,
and Asia show the molossinus Sry allele is restricted to Japan and the
neighboring Asian mainland and confirm that Japanese M. m. molossinus mice
were derived in part from a race of M. m. musculus from Korea or Manchuria.
Sry polymorphisms, as illustrated by the molossinus Sry allele, can serve
as molecular markers for studies on the evolution of wild M. musculus
populations and can help determine the role sex determination plays in
speciation.
相似文献