Isolation and characterization of the Streptococcus mutans gtfC gene, coding for synthesis of both soluble and insoluble glucans.

Pseudomonas syringae pv. phaseolicola is the causal agent of the “halo blight” disease of beans. A key component in the development of the disease is a nonhost-specific toxin, Nδ-(N'-sulphodiaminophosphinyl)-ornithyl-alanyl-homoarginine, known as phaseolotoxin. The homoarginine residue in this molecule has been suggested to be the product of Larginine:lysine amidinotransferase activity, previously detected in extracts of P. syringae pv. phaseolicola grown under conditions of phaseolotoxin production. We report the isolation and characterization of an amidinotransferase gene (amtA) from P. syringae pv. phaseolicola coding for a polypeptide of 362 residues (41.36 kDa) and showing approximately 40% sequence similarity to Larginine:inosamine-phosphate amidinotransferase from three species of Streptomyces spp. and 50.4% with an Larginine:glycine amidinotransferase from human mitochondria. The cysteine, histidine, and aspartic acid residues involved in substrate binding are conserved. Furthermore, expression of the amtA and argK genes and phaseolotoxin production occurs at 18°C but not at 28°C. An amidinotransferase insertion mutant was obtained that lost the capacity to synthesize homoarginine and phaseolotoxin. These results show that the amtA gene isolated is responsible for the amidinotransferase activity detected previously and that phaseolotoxin production depends upon the activity of this gene.

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Isolation and characterization of the gene coding for cytosolic phosphoenolpyruvate carboxykinase (GTP) from the rat.

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.80.12.3656 ◽

1983 ◽

Vol 80 (12) ◽

pp. 3656-3660 ◽

Cited By ~ 119

Author(s):

H. Yoo-Warren ◽

J. E. Monahan ◽

J. Short ◽

H. Short ◽

A. Bruzel ◽

...

Keyword(s):

Phosphoenolpyruvate Carboxykinase ◽

Isolation And Characterization ◽

Gene Coding

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Isolation and characterization of Streptococcus mutans in heart valve and dental plaque specimens from a patient with infective endocarditis

Journal of Medical Microbiology ◽

10.1099/jmm.0.46609-0 ◽

2006 ◽

Vol 55 (8) ◽

pp. 1135-1140 ◽

Cited By ~ 63

Author(s):

Ryota Nomura ◽

Kazuhiko Nakano ◽

Hirotoshi Nemoto ◽

Kazuyo Fujita ◽

Satoko Inagaki ◽

...

Keyword(s):

Infective Endocarditis ◽

Dental Caries ◽

Oral Cavity ◽

Streptococcus Mutans ◽

Heart Valve ◽

Dental Plaque ◽

Biochemical Properties ◽

Oral Streptococci ◽

Isolation And Characterization

Streptococcus mutans, known to be an aetiologic agent of dental caries, also causes infective endocarditis (IE), although a comparison of isolates from the oral cavity and infected heart valve of the same patient has not been reported. In the present study, infected heart valve and dental plaque samples from a patient with IE were analysed. Broad-range PCR with DNA sequencing revealed that 50 clones from the dental plaque isolates were composed of oral streptococci and periodontopathic bacteria, whereas only Streptococcus mutans was detected in 50 clones from the heart valve. Eighteen strains of Streptococcus mutans were isolated from dental plaque and seven from the heart valve, and the biochemical properties of each were in accordance with those of Streptococcus mutans. DNA fingerprinting analysis revealed that all the oral isolates of Streptococcus mutans had similar patterns, which were different from those of the isolates from the infected heart valve. Western blotting using glucosyltransferase (GTF)-specific antiserum showed that the seven strains from the heart valve lacked the three types of intact GTF. In addition, the sucrose-dependent adhesion rates of these isolates were significantly lower than those of the oral isolates (P<0.001). Furthermore, the isolates from the heart valve were less susceptible to erythromycin and kanamycin. These results indicate that the properties of the Streptococcus mutans strains isolated from the infected valve were different from those of typical oral strains, which may be related to the effects of IE.

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Isolation and characterization of regulatory mutants from Schizosaccharomyces pombe involved in thiamine-regulated gene expression.

Genetics ◽

10.1093/genetics/130.3.445 ◽

1992 ◽

Vol 130 (3) ◽

pp. 445-449

Author(s):

A M Schweingruber ◽

H Fankhauser ◽

J Dlugonski ◽

C Steinmann-Loss ◽

M E Schweingruber

Keyword(s):

Acid Phosphatase ◽

Schizosaccharomyces Pombe ◽

Mrna Levels ◽

Wild Type ◽

Transcription Control ◽

Isolation And Characterization ◽

Gene Coding ◽

Thiamine Transport ◽

Regulated Gene Expression

Abstract Mutants from Schizosaccharomyces pombe deficient in the regulation of thiamine-repressible acid phosphatase have been isolated. Mutants expressing derepressed levels of the enzyme in the presence and absence of thiamine map in three genes, tnr1, tnr2 and tnr3. mRNA levels of the pho4 gene (coding for thiamine repressible acid phosphatase) and another thiamine-regulatable gene, thi3 (coding for a thiamine biosynthetic enzyme and corresponding to nmt1) are constitutively synthesized in the mutants. The mutants also exhibit constitutive thiamine transport which is thiamine repressible in wild type. The tnr3 mutants reveal a 10-20-fold higher intracellular thiamine level than tnr1 and tnr2 mutants and wild type. Mutants expressing repressed levels of thiamine-repressible acid phosphatase map in gene thi1. No or little amounts of pho4- and nmt1-specific mRNA can be detected. These mutants are impaired in thiamine uptake and are thiamine auxotrophic due to the inability to synthesize the thiazole moiety of the thiamine molecule. All tested tnr and thi1 alleles are recessive, and thi1 mutations are epistatic over tnr mutations. We assume that the thi1 and tnr genes are involved in thiamine-mediated transcription control.

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