Project description:Investigation of partial genome gene expression level changes in a Desulfovibrio africanus during exponential and stationary phase growth in the presence and absence of 5 ug/L Hg2+ (as HgNO3). Desulfovibrio africanus is a known mercury methylating bacteria
2012-06-07 | GSE32580 | GEO
Project description:Investigating the mercury-methylating microorganisms in urban sewage and biofilms in three areas: Guangzhou Zhongxin, Zhucun, and Panyu
Project description:The glucose dual-affinity transport system (low- and high-affinity) is a conserved strategy exerted by microorganisms to cope with the naturally fluctuating availability of nutrients in the environment. The glucose sensing and uptaking process were believed to be tightly involved in cellulases expression regulation in cellulolytic fungi. However, both the identities and functions of the major molecular components of this evolutionarily conserved system in filamentous fungi remain elusive. Here, we conducted a systematic identification and characterization of the glucose dual-affinity transport system in the model fungus Neurospora crassa. Using RNA sequencing coupled with functional transport analyses, we were able to assign GLT-1 (Km = 18.42 ± 3.38 mM) and HGT-1/-2 (Km = 16.13 ± 0.95 µM and 98.97 ± 22.02 µM) to low- and high-affinity glucose transport systems, respectively. The high-affinity transporters hgt-1/-2 were able to complement a moderate growth defect under high glucose when glt-1 was deleted. Simultaneous deletion of hgt-1/-2 led to extensive derepression of genes for plant cell wall deconstruction on cellulose. This suppression by HGT-1/-2 was connected to both carbon catabolite repression (CCR) and the cyclic adenosine monophosphate-protein kinase A pathway. Alteration of a residue conserved across taxa for hexose-transporters was found to result in a loss of glucose-transporting function, whereas CCR signal transduction was retained, indicating a dual function for HGT-1/-2 as “transceptors”. In this study, GLT-1 and HGT-1/-2 are identified as the key components of the glucose dual-affinity transport system, which play diverse roles in glucose transport and carbon metabolism. Given their wide conservation across fungal species, the glucose dual-affinity transport components and their pleiotropic roles revealed in this study would shed extensive new light on the molecular basis of nutrient transport, signaling, and plant cell wall degradation in fungi.
2017-01-04 | GSE78952 | GEO
Project description:Studies of DOC on mercury-methylating microbial communities and MeHg production
Project description:Gene expression analysis of GI human norovirus (HuNoV) replicon in human gastric tumor cells (HGT-NV), IFN-cured population of replicon-harboring HGT-1 cells (HGT-Cured) and wild-type parental HGT-1 cells (HGT) to provide insight into the cellular factors promoting human norovirus replication in vitro.
Project description:Horizontal gene transfer (HGT) is the major mechanism responsible for spread of antibiotic resistance. Antibiotic treatment has been suggested to promote HGT, either by directly affecting the conjugation process itself or by selecting for conjugations subsequent to DNA transfer. However, recent research suggests that the effect of antibiotic treatment on plasmid conjugation frequencies, and hence the spread of resistance plasmids, may have been overestimated. We addressed the question by quantifying transfer proteins and conjugation frequencies of a blaCTX-M-1 encoding IncI1 resistance plasmid in Escherichia coli MG1655 in the presence and absence of therapeutically relevant concentrations of cefotaxime (CTX). Analysis of the proteome by iTRAQ labeling and liquid chromatography tandem mass spectrometry revealed that Tra proteins were significantly up regulated in the presence of CTX. The up-regulation of the transfer machinery was confirmed at the transcriptional level for five selected genes. The CTX treatment did not cause induction of the SOS39 response as revealed by absence of significantly regulated SOS associated proteins in the proteome and no significant up-regulation of recA and sfiA genes. The frequency of plasmid conjugation, measured in an antibiotic free environment, increased significantly when the donor was pre-grown in broth containing CTX compared to growth without this drug, regardless of whether blaCTX-M-1 was located on the plasmid or in trans on the chromosome. The results shows that antibiotic treatment can affect expression of a plasmid conjugation machinery and subsequent DNA transfer.
Project description:Treatment of severely refractory Crohn’s disease (CD) patients remains a clinical challenge. Recent studies show the efficacy of autologous hematopoietic stem cell transplant (HSCT) in these severely compromised patients. HSCT is thought to eliminate auto-reactive cells; however, no specific studies of immune reconstitution in CD patients are available. We studied a group of CD patients (n=18) receiving autologous HSCT and non-IBD patients (n=19) to elucidate the mechanism of interaction with the microorganisms.
Project description:Investigation of partial genome gene expression level changes in a Desulfovibrio africanus during exponential and stationary phase growth in the presence and absence of 5 ug/L Hg2+ (as HgNO3). Desulfovibrio africanus is a known mercury methylating bacteria A 3 chip study using total RNA recovered from three separate cultures of Desulfovibrio africanus with 5 ug/L Hg during exponential phase growth, three seperate cultures of Desulfovibrio africanus with 5 ug/L Hg during stationary phase growth, three cultures of Desulfovibrio africanus without Hg during exponential phase growth, and Desulfovibrio africanus without Hg during stationary phase growth. Each chip measures the expression level of 4,585 genes and intergenic regions from Desulfovibrio africanus strain Walvis Bay on a custom Nimblegen format with 75-mer probes with tiled in 4-plex format.