Disruption and phenotypic analysis of six open reading frames from chromosome VII of Saccharomyces cerevisiae reveals one essential gene

Six open reading frames (ORFs) located on chromosome VII of Saccharomyces cerevisiae (YGR205w, YGR210c, YGR211w, YGR241c, YGR243w and YGR244c) were disrupted in two different genetic backgrounds using short-flanking homology (SFH) gene replacement. Sporulation and tetrad analysis showed that YGR211w, recently identified as the yeast ZPR1 gene, is an essential gene. The other five genes are non-essential, and no phenotypes could be associated to their inactivation. Two of these genes have recently been further characterized: YGR241c (YAP1802) encodes a yeast adaptor protein and YGR244c (LSC2) encodes the b-subunit of the succinyl-CoA ligase. For each ORF, a replacement cassette with long flanking regions homologous to the target locus was cloned in pUG7, and the cognate wild-type gene was cloned in pRS416

Clusters of 5S rRNAs in the intergenic region of ubiquitin genes in Tetrahymena pyriformis

Here, we report the molecular analysis of two independent 5S rRNA clusters found in the intergenic region of two ubiquitin genomic clones isolated from Tetrahymena pyriformis. Each cluster contains two 120-bp-long coding regions organized in tandem with 142/145-bp-long spacers

O INKHOUK: Apontamentos sobre “a luta pela estrutura sobre o estilo"

O Inkhouk foi entre 1920 e 1924 uma das mais significativas manifestações organizacionais dos grupos de vanguarda soviética; o presente artigo pretende refletir sobre o papel do Inkhouk e como integrado num Estado moderno e numa dinâmica revolucionária essa curta experiência institucional demonstrou que não só era possível aos artistas manterem coletivamente uma reflexão crítica e continuada sobre a linguagem inovadora e de rutura que estavam a desenvolver nas suas obras e nos seus métodos como também demonstrou que era possível aferir como a revolução política e a sua dimensão quotidiana transformara radicalmente o significado social e simbólico do trabalho artístico de vanguarda. O Inkhouk foi o momento em que o ativismo modernista se colocou em pausa reflexiva sem nunca se desligar do turbilhão dos acontecimentos.Palavras-chave: Modernismo; Revolução, Vanguarda; Construtivismo, Suprematismo.DOI: 10.5965/2175234606122014041

Characterization and expression analysis of the cytochrome bd oxidase operon from Desulfovibrio gigas

Abstract: Although classified as anaerobic, Desulfovibrio gigas contains a functional canonical membrane respiratory chain, including a cytochrome bd quinol oxidase as its terminal element. In the present study, we report the identification of the operon cydAB encoding the two subunits of cytochrome bd from this bacterium. Two hypothetical promoter regions and sequences resembling transcriptional regulators-binding sites have been identified. Amino acid sequence analysis revealed a high similarity to cytochrome bd from other organisms, presenting the conserved residues typical from these proteins. Reverse transcription polymerase chain reaction (RT-PCR) and Northern blot analysis confirmed the operon transcription. Gene expression was assessed by real-time RT-PCR in cells grown in different media and under exposure to oxygen and nitric oxide. mRNA levels were slightly enhanced in the presence of 150 mu M NO. However, in the presence of 10 mu M NO, a decrease was observed of the steady-state population of cydAB mRNA. No considerable effect was observed in the presence of fumarate/sulfate medium, 60 mu M O-2 or 10 mu M NO

A novel membrane-bound Ech [NiFe] hydrogenase in Desulfovibrio gigas

Abstract: In the present study, we report the identification of an operon with six coding regions for a multisubunit membrane-bound [NiFe] hydrogenase in the genome of Desulfovibrio gigas. Sequence analysis of the deduced polypeptides reveals a high similarity to subunits of proteins belonging to the family of Ech hydrogenases. The operon is organised similarly to the operon coding for the Ech hydrogenase from Methanosarcina barkeri, suggesting that both encode very similar hydrogenases. Expression of the operon was detected by Northern blot and RT-PCR analyses, and the presence of the encoded proteins was examined by Western blotting. The possible role of this hydrogenase is discussed, relating it with a potential function in the H-2 cycling as a mechanism for energy conservation in D. gigas. The present study provides therefore valuable insights into the open question of the energy conserving mechanism in D. giga

A chemotaxis operon in the bacterium Desulfovibrio gigas is induced under several growth conditions

Abstract: The chemosensory system of bacteria controls their motility and behaviour in different environments. In the present study, we report the identification of the first chemotaxis operon in Desulfovibrio gigas. Amino acid sequence analysis revealed seven coding regions for polypeptides with a high similarity to chemotaxis proteins from other organisms. D. gigas chemotaxis operon has a similar genetic organisation to chemotaxis operons found in the sequenced genomes of Desulfovibrio desulfuricans and Desulfovibrio vulgaris. Control of gene expression was assessed by real-time reverse transcription-PCR in cells grown under different conditions. mRNA levels were enhanced in the presence of thiosulfate and sulfite and decreased upon exposure to NO. No effect was observed in the presence of O-2, NaNO2, pyruvate or fumarate. These results show that the expression of the chemotaxis operon is enhanced in the presence of thiosulfate and sulfite indicating that under these compounds a chemotactic response seems to be triggered in D. gigas

Sequencing of a 9.9 kb segment on the right arm of yeast chromosome VII reveals four open reading frames, including PFK1, the gene coding for succinyl-CoA synthetase (beta-chain) and two ORFs sharing homology with ORFs of the yeast chromosome VIII

A 9.9 kb DNA fragment from the right arm of chromosome VII of Saccharomyces cerevisiae has been sequenced and analysed. The sequence contains four open reading frames (ORFs) longer than 100 amino acids. One gene, PFK1, has already been cloned and sequenced and the other one is the probable yeast gene coding for the beta-subunit of the succinyl-CoA synthetase. The two remaining ORFs share homology with the deduced amino acid sequence (and their physical arrangement is similar to that) of the YHR161c and YHR162w ORFs from chromosome VIII

Deletion of flavoredoxin gene in Desulfovibrio gigas reveals its participation in thiosulfate reduction

Abstract: The gene encoding Desulfovibrio gigas flavoredoxin was deleted to elucidate its physiological role in the sulfate metabolism. Disruption of flr gene strongly inhibited the reduction of thiosulfate and exhibited a reduced growth in the presence of sulfite with lactate as electron donor. The growth with sulfate was not however affected by the lack of this protein. Additionally, flr mutant cells revealed a decrease of about 50% in the H-2 consumption rate using thiosulfate as electron acceptor. Altogether, our results show in vivo that during sulfite respiration, trithionate and thiosulfate are produced and that flavoredoxin is specific for thiosulfate reduction

Characterisation of the 11Kb DNA region adjacent to the gene encoding Desulfovibrio gigas flavoredoxin

Abstract: Flavoredoxin is an FMN binding protein that functions as an electron carrier in the sulphate metabolism of Desulfovibrio gigas. The neighbouring DNA regions of the gene encoding flavoredoxin were sequenced and characterised. Transcript analysis of the flavoredoxin gene resulted in a positive band corresponding to the size of the coding region, suggesting that flavoredoxin is encoded by a monocystronic unit, as previously suggested by sequence analysis

Structure of Tetrahymena CCTθ gene and its expression under colchicine treatment

We report here the cloning and the characterization of the Tetrahymena pyriformis chaperonin-containing-TCP1 theta gene (TpCCTθ), an orthologue of the mouse chaperonin gene CCTθ. TpCCTθ gene is interrupted by eight introns, ranging in size between 91 and 419 nucleotides, and encodes a protein consisting of 540 amino acid residues (59.1 kDa), with a putative pI of 5.73. The amino acid sequence of TpCCTθ reveals 39.4–46.0% identity with the sequences of Candida albicans and mouse CCTθ subunits and 28.0–32.6% identity with the other TpCCT subunits known so far. We have studied the expression of this gene in exponentially growing Tetrahymena cells and in cells treated with colchicine for different times. The steady-state levels of CCTθ mRNA rapidly decrease in the first 30 min of colchicine treatment. Interestingly, treatment for subsequent 60 min gives expression levels higher than those found in exponentially growing cells.info:eu-repo/semantics/publishedVersio