Maintenance of DeltapH by a butanol-tolerant mutant of Clostridium beijerinckii.

The isolation of Clostridium beijerinckii mutants that are more tolerant of butanol than the wild-type offered the opportunity to investigate whether the membrane activities which are required for maintaining the transmembrane DeltapH (the difference in pH between the cellular interior and exterior) are sensitive targets of butanol toxicity. The DeltapH was measured by the accumulation of [14C]benzoate using late-exponential-phase cells which were suspended in citrate/phosphate buffer at pH 5 (to maximize the DeltapH component of the protonmotive force) and supplemented with glucose and Mg2+. The DeltapH of the butanol-tolerant tolerant mutant, strain BR54, of C.

Accumulation of methylglyoxal in the gingival crevicular fluid of chronic periodontitis patients.

Background, Aims: Methylglyoxal (MG), a toxic product of cellular metabolism, is elevated in tissues and fluids in a number of human diseases. A cross-sectional study was undertaken to determine whether MG accumulates in the gingival crevicular fluid (GCF) of chronic periodontitis patients.

Methods: GCF samples were collected for 30 s each from three teeth with pocket depths greater than 3 mm (DD sites), from 14 chronic periodontitis patients.

Clostridium beijerinckii and Clostridium difficile detoxify methylglyoxal by a novel mechanism involving glycerol dehydrogenase.

In contrast to gram-negative bacteria, little is known about the mechanisms by which gram-positive bacteria degrade the toxic metabolic intermediate methylglyoxal (MG). Clostridium beijerinckii BR54, a Tn1545 insertion mutant of the NCIMB 8052 strain, formed cultures that contained significantly more (free) MG than wild-type cultures. Moreover, BR54 was more sensitive to growth inhibition by added MG than the wild type, suggesting that it has a reduced ability to degrade MG.

A new insertion sequence, ISCb1, from Clostridium beijernickii NCIMB 8052.

The NCIMB 8052 strain of Clostridium beijerinckii contains nine copies of a novel insertion sequence, ISCb1, belonging to the IS4 family. The 1764 bp element has 18 bp inverted repeats at its extremities, and generates 11 bp target repeats upon insertion. It contains a 1365 bp ORF whose predicted product (455 amino acids) resembles bacterial transposases.

Butanol tolerance of Clostridium beijerinckii NCIMB 8052 associated with down-regulation of gldA by antisense RNA.

Strain BR54 of Clostridium beijerinckii was derived from the wild type strain, NCIMB 8052, by mutagenesis with Tn1545 and selection for butanol tolerance. It harbours a single copy of Tn 1545 in a 435 bp intergenic region separating two convergently transcribed genes, accC and gldA. The former encodes biotin carboxylase (E.