scholarly journals Isolation and Characterization of a Vibrio vulnificus Mutant Deficient in Both Extracellular Metalloprotease and Cytolysin

2001 ◽  
Vol 69 (9) ◽  
pp. 5943-5948 ◽  
Author(s):  
Jong-Jin Fan ◽  
Chung-Ping Shao ◽  
Ya-Chi Ho ◽  
Chun-Keung Yu ◽  
Lien-I Hor
Keyword(s):  
Type Strain ◽  
Alimentary Tract ◽  
Wild Type Strain ◽  
Vibrio Vulnificus ◽  
Wild Type ◽  
Allelic Exchange ◽  
Isolation And Characterization

ABSTRACT We isolated a Vibrio vulnificus mutant that was deficient in both metalloprotease and cytolysin by allelic exchange. The virulence of this mutant in mice and its cytotoxicity for HEp-2 cells were comparable to those of the wild-type strain, indicating that neither factor was essential for these properties. The cytolysin, but not the protease, seemed to be important for causing damage in the alimentary tract of the mice.

scholarly journals Biochemical genetics of Neurospora nuclease I: Isolation and characterization of nuclease (nuc) mutants

1983 ◽  
Vol 41 (3) ◽  
pp. 271-286 ◽  
Author(s):  
A. M. Forsthoefel ◽  
N. C. Mishra
Keyword(s):  
Nucleic Acids ◽  
Type Strain ◽  
Wild Type Strain ◽  
Extracellular Enzymes ◽  
Spontaneous Mutation ◽  
Subsequent Paper ◽  
Wild Type ◽  
Isolation And Characterization ◽  
Phosphorus Source

SUMMARYIsolation and characterization of five new nuclease (nuc) deficient mutants ofNeurosporahave been described. The new mutants are unable to utilize nucleic acids as the sole phosphorus source and possess growth characteristics similar to thosenuc(nuc-1andnuc-2) mutants described previously. Two new mutants (nuc-4andnuc-5) were able to use RNA or predigested DNA (but not intact DNA) as phosphorus source and showed temperature sensitive growth at 37 °C. Based on the data from complementation and genetic analyses the five new nuc mutants (nuc-3, nuc-4, nuc-5, nuc-6andnuc-7) were found nonallelic to each other and to previously describednuc(nuc-1andnuc-2) mutants; the newnucmutants mapped to the right ofarg-12on linkage group II. On biochemical analyses, thesenucmutants were found to possess a lower level of extracellular nucleases and alkaline phosphatase as compared to the wild type strain. The ds DNase activity of the new mutants was only about 2–12% of that of the wild type strain; thus, the low level of these extracellular enzymes in thenucmutants causes their inability to utilize nucleic acids as the sole phosphorus source. Wild type levels of these enzymes were restored in the complementing heterokaryons capable of full growth on the DNA medium. Data from intercrosses, mutagen sensitivity and spontaneous mutation-frequency studies (as discussed in a subsequent paper) indicated the involvement of thenucgenes in DNA repair and recombination.

Isolation and characterization of a mutator strain of Streptomyces ambofaciens ATCC23877 exhibiting an increased level of genetic instability

1996 ◽  
Vol 42 (6) ◽  
pp. 562-570 ◽  
Author(s):  
Dominique Vandewiele ◽  
Jean-Nicolas Volff ◽  
Bertrand Aigle ◽  
Jean-Marc Simonet ◽  
Bernard Decaris
Keyword(s):  
Genetic Instability ◽  
Type Strain ◽  
Wild Type Strain ◽  
Genomic Analysis ◽  
Wild Type ◽  
Mutator Strain ◽  
Isolation And Characterization ◽  
Streptomyces Ambofaciens ◽  
In The Wild

In Streptomyces ambofaciens ATCC23877, 0.7% of pigment-defective mutants (Pig−) can be observed in the progeny of wild-type colonies. A mutator (Mut−) strain was isolated from the offspring of the wild-type strain. The Mut− strain produced colonies that sported nonpigmented papillae. Furthermore, the frequency of Pig− colonies obtained in the progeny of this strain was fivefold higher than in the wild-type strain. This strain showed the same level of sensitivity to ultraviolet light and mitomycin C as the wild-type strain. This Mut− phenotype was found to be reversible at high frequency (3 × 10−3). Genomic analysis using pulsed-field gel electrophoresis (PFGE) showed that the Pig− mutants arisen from the Mut− strain were less frequently rearranged (32% were deleted) compared with the mutants arising from the wild type (59% were deleted). Moreover, the Pig− papillae mutants possessed no visible rearrangement as revealed by PFGE analyses.Key words: Streptomyces, genetic instability, mutator strain, papillae.

scholarly journals Characterization of a Wild-Type Strain ofFrancisella TularensisIsolated from a Cat

2004 ◽  
Vol 16 (5) ◽  
pp. 374-381 ◽  
Author(s):  
Thomas J. Inzana ◽  
Gretchen E. Glindemann ◽  
Gerald Snider ◽  
Susan Gardner ◽  
Lisa Crofton ◽  
...  
Keyword(s):  
Type Strain ◽  
Wild Type Strain ◽  
Wild Type

scholarly journals Regulation and Characterization of a Newly Deduced Cell Wall Hydrolase Gene (cwlJ) Which Affects Germination of Bacillus subtilis Spores

1998 ◽  
Vol 180 (6) ◽  
pp. 1375-1380 ◽  
Author(s):  
Shu Ishikawa ◽  
Kunio Yamane ◽  
Junichi Sekiguchi
Keyword(s):  
Bacillus Subtilis ◽  
Type Strain ◽  
Wild Type Strain ◽  
Catalytic Domain ◽  
Slow Release ◽  
Dipicolinic Acid ◽  
Northern Hybridization ◽  
Predicted Amino Acid Sequence ◽  
Wild Type

ABSTRACT The predicted amino acid sequence of Bacillus subtilis ycbQ (renamed cwlJ) exhibits high similarity to those of the deduced C-terminal catalytic domain of SleBs, the specific cortex-hydrolyzing enzyme of B. cereus and the deduced one of B. subtilis. We constructed acwlJ::lacZ fusion in the B. subtilischromosome. The β-galactosidase activity and results of Northern hybridization and primer extension analyses of the cwlJgene indicated that it is transcribed by EςE RNA polymerase. cwlJ-deficient spores responded to bothl-alanine and AGFK, the A 580 values of spore suspensions decreased more slowly than in the case of the wild-type strain, and the mutant spores released less dipicolinic acid than did those of the wild-type strain during germination. However, the mutant spores released only slightly less hexosamine than did the wild-type spores. In contrast, B. subtilis sleB spores did not release hexosamine at a significant level. While cwlJand sleB spores were able to germinate, CJSB (cwlJ sleB) spores could not germinate but exhibited initial germination reactions, e.g., partial decrease inA 580 and slow release of dipicolinic acid. CJSB spores became slightly gray after 6 h in the germinant, but their refractility was much greater than that of sleB mutant spores. The roles of the sleB and cwlJmutations in germination and spore maturation are also discussed.

scholarly journals Characterization of melanin produced by a wild-type strain of Bacillus thuringiensis

2004 ◽  
Vol 50 (4) ◽  
pp. 183-188 ◽  
Author(s):  
Yuehua Chen ◽  
Yinyue Deng ◽  
Jinhong Wang ◽  
Jun Cai ◽  
Gaixin Ren
Keyword(s):  
Bacillus Thuringiensis ◽  
Type Strain ◽  
Wild Type Strain ◽  
Wild Type

Purification and characterization of a β-glucosidase from Streptomyces lividans 66

1990 ◽  
Vol 36 (1) ◽  
pp. 53-56 ◽  
Author(s):  
Anca Mihoc ◽  
Dieter Kluepfel
Keyword(s):  
High Performance Liquid Chromatography ◽  
Molecular Sieve ◽  
Type Strain ◽  
High Performance ◽  
Wild Type Strain ◽  
Streptomyces Lividans ◽  
Wild Type ◽  
Purification And Characterization ◽  
Anion Exchange Column

An intracellular β-1, 4-D-glucosidase (EC 3.2.1.21) was isolated from the mutant strain HP-3 of Streptomyces lividans 66 which produced about 12 times more enzyme than the wild-type strain. The purification was carried out by anion exchange column chromatography followed by high-performance liquid chromatography on DEAE and on molecular sieve columns. The enzyme is glycosylated and has an apparent Mr of 51 000 and a pI of 4.3. Its activity was optimal at pH 6.5 and at a temperature of 40 °C. The Km and the Vmax on cellobiose were 3.1 mM and 65.6 μmol min−1 mg−1 of enzyme. Key words: β-glucosidase, Streptomyces lividans, purification, characterization.

scholarly journals Mutation of waaC, Encoding Heptosyltransferase I in Campylobacter jejuni 81-176, Affects the Structure of both Lipooligosaccharide and Capsular Carbohydrate

2006 ◽  
Vol 188 (9) ◽  
pp. 3273-3279 ◽  
Author(s):  
Margaret I. Kanipes ◽  
Erzsebet Papp-Szabo ◽  
Patricia Guerry ◽  
Mario A. Monteiro
Keyword(s):  
Campylobacter Jejuni ◽  
Type Strain ◽  
Insertional Mutagenesis ◽  
Lipid A ◽  
Wild Type Strain ◽  
Capsular Polysaccharide ◽  
Resonance Spectroscopy ◽  
Gas Liquid Chromatography ◽  
Wild Type ◽  
Isolation And Characterization

ABSTRACT Campylobacter jejuni 81-176 lipooligosaccharide (LOS) is composed of two covalently linked domains: lipid A, a hydrophobic anchor, and a nonrepeating core oligosaccharide, consisting of an inner and outer core region. We report the isolation and characterization of the deepest rough C. jejuni 81-176 mutant by insertional mutagenesis into the waaC gene, encoding heptosyltransferase I that catalyzes the transfer of the first l-glycero-d-manno-heptose residue to 3-deoxy-d-manno-octulosonic residue (Kdo)-lipid A. Tricine gel electrophoresis, followed by silver staining, showed that site-specific mutation in the waaC gene resulted in the expression of a severely truncated LOS compared to wild-type strain 81-176. Gas-liquid chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy showed that the waaC LOS species lacked all sugars distal to Kdo-lipid A. Parallel structural studies of the capsular polysaccharides of the wild-type strain 81-176 and waaC mutant revealed loss of the 3-O-methyl group in the waaC mutant. Complementation of the C. jejuni mutant by insertion of the wild-type C. jejuni waaC gene into a chromosomal locus resulted in LOS and capsular structures identical to those expressed in the parent strain. We also report here the presence of O-methyl phosphoramidate in wild-type strain 81-176 capsular polysaccharide.

scholarly journals Isolation and Characterization of Burkholderia cenocepacia Mutants Deficient in Pyochelin Production: Pyochelin Biosynthesis Is Sensitive to Sulfur Availability

2004 ◽  
Vol 186 (2) ◽  
pp. 270-277 ◽  
Author(s):  
Kate L. Farmer ◽  
Mark S. Thomas
Keyword(s):  
Wild Type Strain ◽  
Opportunistic Pathogen ◽  
Burkholderia Cenocepacia ◽  
Wild Type ◽  
Iron Starvation ◽  
Gene Encoding ◽  
Isolation And Characterization ◽  
Putative Operon ◽  
Green Fluorescent

ABSTRACT The opportunistic pathogen Burkholderia cenocepacia produces the yellow-green fluorescent siderophore, pyochelin. To isolate mutants which do not produce this siderophore, we mutagenized B. cenocepacia with the transposon mini-Tn5Tp. Two nonfluorescent mutants were identified which were unable to produce pyochelin. In both mutants, the transposon had integrated into a gene encoding an orthologue of CysW, a component of the sulfate/thiosulfate transporter. The cysW gene was located within a putative operon encoding other components of the transporter and a polypeptide exhibiting high homology to the LysR-type regulators CysB and Cbl. Sulfate uptake assays confirmed that both mutants were defective in sulfate transport. Growth in the presence of cysteine, but not methionine, restored the ability of the mutants to produce pyochelin, suggesting that the failure to produce the siderophore was the result of a depleted intracellular pool of cysteine, a biosynthetic precursor of pyochelin. Consistent with this, the wild-type strain did not produce pyochelin when grown in the presence of lower concentrations of sulfate that still supported efficient growth. We also showed that whereas methionine and certain organosulfonates can serve as sole sulfur sources for this bacterium, they do not facilitate pyochelin biosynthesis. These observations suggest that, under conditions of sulfur depletion, cysteine cannot be spared for production of pyochelin even under iron starvation conditions.

scholarly journals Characterization of emeA, anorA Homolog and Multidrug Resistance Efflux Pump, inEnterococcus faecalis

2001 ◽  
Vol 45 (12) ◽  
pp. 3574-3579 ◽  
Author(s):  
Brandie M. Jonas ◽  
Barbara E. Murray ◽  
George M. Weinstock
Keyword(s):  
Drug Resistance ◽  
Multidrug Resistance ◽  
Type Strain ◽  
Deletion Mutant ◽  
Wild Type Strain ◽  
Efflux Pump ◽  
Wild Type ◽  
Type Gene ◽  
Encoding Genes

ABSTRACT We hypothesized that multidrug resistance efflux pumps (MDRs) may be contributing to the drug resistance of enterococci. We recently identified potential MDR-encoding genes in the Enterococcus faecalis V583 genome. Among the putative MDRs, we found a gene that encodes a NorA homolog and have characterized this enterococcal MDR in the present study. A mutant from which the enterococcal NorA homolog has been deleted has reduced resistance to several NorA substrates. Complementation of the deletion mutant with the wild-type gene verified the involvement of this enterococcal gene in resistance to ethidium bromide (EtBr) and norfloxacin. Known MDR inhibitors (reserpine, lansoprazole, and verapamil) inhibit the efflux of EtBr and norfloxacin in wild-type strain OG1RF. A fluorescence assay with EtBr allowed us to quantitate the efflux capability of the enterococcal NorA pump. On the basis of these results, we have named this enterococcal gene emeA (enterococcal multidrug resistance efflux).

scholarly journals Characterization of Human Bactericidal Antibodies to Bordetella pertussis

1999 ◽  
Vol 67 (3) ◽  
pp. 1424-1431 ◽  
Author(s):  
Alison A. Weiss ◽  
Paula S. Mobberley ◽  
Rachel C. Fernandez ◽  
ChrisAnna M. Mink
Keyword(s):  
Immune Response ◽  
Bactericidal Activity ◽  
Bordetella Pertussis ◽  
Type Strain ◽  
Wild Type Strain ◽  
Resistance Mechanism ◽  
Wild Type ◽  
Occupationally Exposed ◽  
Bactericidal Activities

ABSTRACT The Bordetella pertussis BrkA protein protects against the bactericidal activity of complement and antibody; however, some individuals mount an immune response that overcomes this bacterial defense. To further characterize this process, the bactericidal activities of sera from 13 adults with different modes of exposure toB. pertussis (infected as adults, occupational exposure, immunized with an acellular vaccine, or no identified exposure) against a wild-type strain and a BrkA complement-sensitive mutant were evaluated. All of the sera killed the BrkA mutant, suggesting past exposure to B. pertussis or cross-reactive organisms. Several samples had no or minimal activity against the wild type. All of the sera collected from the infected and occupationally exposed individuals but not all of the sera from vaccinated individuals had bactericidal activity against the wild-type strain, suggesting that some types of exposure can induce an immune response that can overcome the BrkA resistance mechanism. Adsorbing serum with the wild-type strain removed the bactericidal antibodies; however, adsorbing the serum with a lipopolysaccharide (LPS) mutant or an avirulent (bvg mutant) strain did not always result in loss of bactericidal activity, suggesting that antibodies to either LPS orbvg-regulated proteins could be bactericidal. All the samples, including those that lacked bactericidal activity, contained antibodies that recognized the LPS of B. pertussis. Bactericidal activity correlated best with the presence of the immunoglobulin G3 (IgG3) antibodies to LPS, the IgG subtype that is most effective at fixing complement.

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