scholarly journals Cloning, Identification, and Characterization of therpoS-Like Sigma FactorrpoXfromVibrio alginolyticus

2009 ◽  
Vol 2009 ◽  
pp. 1-9 ◽  
Author(s):  
Jing-jing Zhao ◽  
Chang Chen ◽  
Lv-ping Zhang ◽  
Chao-qun Hu
Keyword(s):  
Hydrogen Peroxide ◽  
Survival Rate ◽  
Sigma Factor ◽  
Biofilm Formation ◽  
Phase Variation ◽  
Wild Type ◽  
Switching Rate ◽  
Gene Encoding ◽  
Identification And Characterization

Vibrio alginolyticusZJ-51 displays phase variation between opaque/rugose colonies (Op) and translucent/smooth colonies (Tr). These colony variants show great differences in biofilm formation and motility. In this study, a gene encoding for anrpoS-like sigma factor,rpoX, has been cloned and characterized. The absence ofrpoXdid not affect colony switching rate but did decrease biofilm formation in both the Op and the Tr variants. When challenged with hydrogen peroxide, theΔrpoXin the Op background showed a slightly higher survival rate compared with the wild type, whereas survival was decreased in the Tr background. Deletion ofrpoXin the Tr background resulted in a higher ability to resist ethanol challenges and to survive hyperosmolarity challenges, and in the Op background the opposite phenotype was observed. This indicates that therpoXgene is involved in biofilm formation and stress response but the effects are controlled by colony phase variation inV. alginolyticus.

scholarly journals Identification and Characterization of the Bacillus thuringiensis phaZ Gene, Encoding New Intracellular Poly-3-Hydroxybutyrate Depolymerase

2006 ◽  
Vol 188 (21) ◽  
pp. 7592-7599 ◽  
Author(s):  
Chi-Ling Tseng ◽  
Hui-Ju Chen ◽  
Gwo-Chyuan Shaw
Keyword(s):  
Bacillus Thuringiensis ◽  
Wild Type ◽  
Gene Encoding ◽  
Significant Similarity ◽  
Phb Depolymerase ◽  
New Type ◽  
Identification And Characterization

ABSTRACTA gene that codes for a novel intracellular poly-3-hydroxybutyrate (PHB) depolymerase has now been identified in the genome ofBacillus thuringiensissubsp.israelensisATCC 35646. This gene, previously annotated as a hypothetical 3-oxoadipate enol-lactonase (PcaD) gene and now designatedphaZ, encodes a protein that shows no significant similarity with any known PHB depolymerase. Purified His-tagged PhaZ could efficiently degrade trypsin-activated native PHB granules as well as artificial amorphous PHB granules and release 3-hydroxybutyrate monomer as a hydrolytic product, but it could not hydrolyze denatured semicrystalline PHB. In contrast, purified His-tagged PcaD ofPseudomonas putidawas unable to degrade trypsin-activated native PHB granules and artificial amorphous PHB granules. TheB. thuringiensisPhaZ was inactive againstp-nitrophenylpalmitate, tributyrin, and triolein. Sonication supernatants of the wild-typeB. thuringiensiscells exhibited a PHB-hydrolyzing activity in vitro, whereas those prepared from aphaZmutant lost this activity. ThephaZmutant showed a higher PHB content than the wild type at late stationary phase of growth in a nutrient-rich medium, indicating that this PhaZ can function as a PHB depolymerase in vivo. PhaZ contains a lipase box-like sequence (G-W-S102-M-G) but lacks a signal peptide. A purified His-tagged S102A variant had lost the PHB-hydrolyzing activity. Taken together, these results indicate thatB. thuringiensisharbors a new type of intracellular PHB depolymerase.

Identification and characterization of the gene encoding the Acidobacterium capsulatum major sigma factor

Gene ◽  
2006 ◽  
Vol 376 (1) ◽  
pp. 144-151 ◽  
Author(s):  
Zakee L. Sabree ◽  
Veit Bergendahl ◽  
Mark R. Liles ◽  
Richard R. Burgess ◽  
Robert M. Goodman ◽  
...  
Keyword(s):  
Sigma Factor ◽  
Gene Encoding ◽  
Identification And Characterization

scholarly journals Identification and Characterization of theErwinia amylovora rpoS Gene: RpoS Is Not Involved in Induction of Fireblight Disease Symptoms

1998 ◽  
Vol 180 (24) ◽  
pp. 6789-6792 ◽  
Author(s):  
M. Anderson ◽  
C. E. Pollitt ◽  
I. S. Roberts ◽  
J. A. Eastgate
Keyword(s):  
Sigma Factor ◽  
Erwinia Amylovora ◽  
Environmental Stresses ◽  
Alternative Sigma Factor ◽  
Gene Encoding ◽  
Disease Symptoms ◽  
Highly Sensitive ◽  
Identification And Characterization ◽  
Sigma Factor Rpos

ABSTRACT The Erwinia amylovora rpoS gene, encoding the alternative sigma factor RpoS, has been cloned and characterized. Though highly sensitive to a number of environmental stresses, anE. amylovora rpoS mutant was not compromised in its ability to grow or cause disease symptoms within apple seedlings or in an overwintering model.

Molecular characterization of three mutations in katG affecting the activity of hydroperoxidase I of Escherichia coli

1990 ◽  
Vol 68 (7-8) ◽  
pp. 1037-1044 ◽  
Author(s):  
Peter C. Loewen ◽  
Jacek Switala ◽  
Mark Smolenski ◽  
Barbara L. Triggs-Raine
Keyword(s):  
Escherichia Coli ◽  
Specific Activity ◽  
Polymerase Chain Reaction Amplification ◽  
Protein A ◽  
Wild Type ◽  
Wild Type Enzyme ◽  
Gene Encoding ◽  
Reaction Amplification ◽  
Mutant Genes

Hydroperoxidase I (HPI) of Escherichia coli is a bifunctional enzyme exhibiting both catalase and peroxidase activities. Mutants lacking appreciable HPI have been generated using nitrosoguanidine and the gene encoding HPI, katG, has been cloned from three of these mutants using either classical probing methods or polymerase chain reaction amplification. The mutant genes were sequenced and the changes from wild-type sequence identified. Two mutants contained G to A changes in the coding strand, resulting in glycine to aspartate changes at residues 119 (katG15) and 314 (katG16) in the deduced amino acid sequence of the protein. A third mutant contained a C to T change resulting in a leucine to phenylalanine change at residue 139 (katG14). The Phe139-, Asp119-, and Asp314-containing mutants exhibited 13, < 1, and 18%, respectively, of the wild-type catalase specific activity and 43, 4, and 45% of the wild-type peroxidase specific activity. All mutant enzymes bound less protoheme IX than the wild-type enzyme. The sensitivities of the mutant enzymes to the inhibitors hydroxylamine, azide, and cyanide and the activators imidazole and Tris were similar to those of the wild-type enzyme. The mutant enzymes were more sensitive to high temperature and to β-mercaptoethanol than the wild-type enzyme. The pH profiles of the mutant catalases were unchanged from the wild-type enzyme.Key words: catalase, hydroperoxidase I, mutants, sequence analysis.

scholarly journals Identification and characterization of YLR328W, theSaccharomyces cerevisiaestructural gene encoding NMN adenylyltransferase. Expression and characterization of the recombinant enzyme

FEBS Letters ◽  
1999 ◽  
Vol 455 (1-2) ◽  
pp. 13-17 ◽  
Author(s):  
Monica Emanuelli ◽  
Francesco Carnevali ◽  
Maria Lorenzi ◽  
Nadia Raffaelli ◽  
Adolfo Amici ◽  
...  
Keyword(s):  
Recombinant Enzyme ◽  
Gene Encoding ◽  
Identification And Characterization

scholarly journals Identification and Characterization of OscR, a Transcriptional Regulator Involved in Osmolarity Adaptation in Vibrio cholerae

2009 ◽  
Vol 191 (13) ◽  
pp. 4082-4096 ◽  
Author(s):  
Nicholas J. Shikuma ◽  
Fitnat H. Yildiz
Keyword(s):  
Vibrio Cholerae ◽  
Biofilm Formation ◽  
Transcriptional Regulator ◽  
Dependent Manner ◽  
Genome Wide ◽  
Low Salt ◽  
Adaptation Response ◽  
Matrix Production ◽  
Identification And Characterization

ABSTRACT Vibrio cholerae is a facultative human pathogen. In its aquatic habitat and as it passes through the digestive tract, V. cholerae must cope with fluctuations in salinity. We analyzed the genome-wide transcriptional profile of V. cholerae grown at different NaCl concentrations and determined that the expression of compatible solute biosynthesis and transporter genes, virulence genes, and genes involved in adhesion and biofilm formation is differentially regulated. We determined that salinity modulates biofilm formation, and this response was mediated through the transcriptional regulators VpsR and VpsT. Additionally, a transcriptional regulator controlling an osmolarity adaptation response was identified. This regulator, OscR (osmolarity controlled regulator), was found to modulate the transcription of genes involved in biofilm matrix production and motility in a salinity-dependent manner. oscR mutants were less motile and exhibited enhanced biofilm formation only under low-salt conditions.

scholarly journals Slipped strand mispairing in the gene encoding sialidase NanH3 in Gardnerella spp

2020 ◽  
Author(s):  
Shakya P. Kurukulasuriya ◽  
Mo H. Patterson ◽  
Janet E. Hill
Keyword(s):  
Cell Wall ◽  
Biofilm Formation ◽  
Gene Sequence ◽  
Phase Variation ◽  
Cell Wall Proteins ◽  
Vaginal Microbiome ◽  
Gene Encoding ◽  
Reading Frame ◽  
Sialidase Activity ◽  
Mucosal Surfaces

AbstractCell wall proteins with sialidase activity are involved in carbohydrate assimilation, adhesion to mucosal surfaces, and biofilm formation. Gardnerella spp. inhabit the human vaginal microbiome and encode up to three sialidase enzymes, two of which are suspected to be cell wall associated. Here we demonstrate that the gene encoding extracellular sialidase NanH3 is found almost exclusively in G. piotii and closely related Gardnerella genome sp. 3, and its presence correlates with sialidase positive phenotype in a collection of 112 Gardnerella isolates. The nanH3 gene sequence includes a homopolymeric repeat of cytosines that varies in length within cell populations, indicating that this gene is subject to slipped-strand mispairing, a mechanisms of phase variation in bacteria. Variation in the length of the homopolymer sequence results in encoding of either the full length sialidase protein or truncated peptides lacking the sialidase domain due to introduction of reading-frame shifts and premature stop codons. Phase variation in NanH3 may be involved in immune evasion or modulation of adhesion to host epithelial cells, and formation of biofilms characteristic of the vaginal dysbiosis known as bacterial vaginosis.

Characterization of yeast V-ATPase mutants lacking Vph1p or Stv1p and the effect on endocytosis

2002 ◽  
Vol 205 (9) ◽  
pp. 1209-1219 ◽  
Author(s):  
Natalie Perzov ◽  
Vered Padler-Karavani ◽  
Hannah Nelson ◽  
Nathan Nelson
Keyword(s):  
Sucrose Gradient ◽  
Ph Sensor ◽  
Wild Type ◽  
Gene Encoding ◽  
Yeast Saccharomyces Cerevisiae ◽  
Vacuolar Acidification ◽  
Atpase Subunits ◽  
Immunological Assays ◽  
Gradient Fractionation

SUMMARYSubunit a of V-ATPase in the yeast Saccharomyces cerevisiae, in contrast to its other subunits, is encoded by two genes VPH1 and STV1. While disruption of any other gene encoding the V-ATPase subunits results in growth arrest at pH 7.5, null mutants of Vph1p or Stv1p can grow at this pH. We used a polyclonal antibody to yeast Stv1p and a commercially available monoclonal antibody to Vph1p for analysis of yeast membranes by sucrose gradient fractionation, and two different vital dyes to characterize the phenotype of vph1 ▵ and stv1 ▵mutants as compared to the double mutant and the wild-type cells. Immunological assays of sucrose gradient fractions revealed that the amount of Stv1p was elevated in the vph1 ▵ strain, and that vacuoles purified by this method with no detectable endosomal contamination contain an assembled V-ATPase complex, but with much lower activity than the wild type. These results suggest that Stv1p compensates for the loss of Vph1p in the vph1 ▵ strain. LysoSensor Green DND-189 was used as a pH sensor to demonstrate unexpected changes in vacuolar acidification in stv1▵ as the Vph1p-containing V-ATPase complex is commonly considered to acidify the vacuoles. In the vph1 ▵ strain, the dye revealed slight but definite acidification of the vacuole as well. The lipophilic dye FM4-64 was used as an endocytic marker. We show that the null V-ATPase mutants, as well as the vph1 ▵ one, markedly slow down endocytosis of the dye.

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