Biomedical subjects

Takeru Ishige

Publications and source records attributed to Takeru Ishige.

6 recordsLinked to original sources

PubMed2006

Two-component systems of Corynebacterium glutamicum: deletion analysis and involvement of the PhoS-PhoR system in the phosphate starvation response.

Corynebacterium glutamicum contains genes for 13 two-component signal transduction systems. In order to test for their essentiality and involvement in the adaptive response to phosphate (Pi) starvation, a set of 12 deletion mutants was constructed. One of the mutants was specifically impaired in its ability to grow under Pi limitation, and therefore the genes lacking in this strain were named phoS (encoding the sensor kinase) and phoR (encoding the response regulator). DNA microarray analyses with the C. glutamicum wild type and the DeltaphoRS mutant supported a role for the PhoRS system in the adaptation to Pi starvation. In contrast to the wild type, the DeltaphoRS mutant did not induce the known Pi starvation-inducible (psi) genes within 1 hour after a shift from Pi excess to Pi limitation, except for the pstSCAB operon, which was still partially induced. This indicates an activator function for PhoR and the existence of at least one additional regulator of the pst operon. Primer extension analysis of selected psi genes (pstS, ugpA, phoR, ushA, and nucH) confirmed the microarray data and provided evidence for positive autoregulation of the phoRS genes.

Bacterial Proteins↗

PubMed2005

Whole organism biocatalysis.

The use of biocatalysts for the industrial synthesis of chemicals has been attracting much attention as an environment-friendly synthetic method. Microbial cells play a leading role in 'chemo-enzymatic synthesis' because of their great diversity. Several microbes with unique catalytic abilities have been found through intensive screening and put to practical use. Besides, advanced molecular biological techniques are powerful tools for developing more satisfactory biocatalysts.

Bacteria↗

PubMed2003

Wax ester production by bacteria.

The enzymological and genetic aspects of microbial metabolism of hydrocarbons have been extensively revealed. Such molecular information is useful for understanding the bioremediation of oil spill environments and production of hydrocarbon-specific fine chemicals.

Bacteria↗

PubMed2003

The phosphate starvation stimulon of Corynebacterium glutamicum determined by DNA microarray analyses.

The phosphate (P(i)) starvation stimulon of Corynebacterium glutamicum was characterized by global gene expression analysis by using DNA microarrays. Hierarchical cluster analysis of the genes showing altered expression 10 to 180 min after a shift from P(i)-sufficient to P(i)-limiting conditions led to identification of five groups comprising 92 genes. Four of these groups included genes which are not directly involved in P metabolism and changed expression presumably due to the reduced growth rate observed after the shift or to the exchange of medium. One group, however, comprised 25 genes, most of which are obviously related to phosphorus (P) uptake and metabolism and exhibited 4- to >30-fold-greater expression after the shift to P(i) limitation. Among these genes, the RNA levels of the pstSCAB (ABC-type P(i) uptake system), glpQ (glycerophosphoryldiester phosphodiesterase), ugpAEBC (ABC-type sn-glycerol 3-phosphate uptake system), phoH (unknown function), nucH (extracellular nuclease), and Cgl0328 (5'-nucleotidase or related esterase) genes were increased, and pstSCAB exhibited a faster response than the other genes. Transcriptional fusion analyses revealed that elevated expression of pstSCAB and ugpAEBC was primarily due to transcriptional regulation. Several genes also involved in P uptake and metabolism were not affected by P(i) starvation; these included the genes encoding a PitA-like P(i) uptake system and a putative Na(+)-dependent P(i) transporter and the genes involved in the metabolism of pyrophosphate and polyphosphate. In summary, a global, time-resolved picture of the response of C. glutamicum to P(i) starvation was obtained.

Bacterial Proteins↗

PubMed2002

Wax ester production from n-alkanes by Acinetobacter sp. strain M-1: ultrastructure of cellular inclusions and role of acyl coenzyme A reductase.

Acinetobacter sp. strain M-1 accumulated a large amount of wax esters from an n-alkane under nitrogen-limiting conditions. Under the optimized conditions with n-hexadecane as the substrate, the amount of hexadecyl hexadecanoate in the cells reached 0.17 g/g of cells (dry weight). Electron microscopic analysis revealed that multilayered disk-shaped intracellular inclusions were formed concomitant with wax ester formation. The contribution of acyl-CoA reductase to wax ester synthesis was evaluated by gene disruption analysis.

Acinetobacter↗

PubMed2002

Two acyl-CoA dehydrogenases of Acinetobacter sp. strain M-1 that uses very long-chain n-alkanes.

Two genes encoding acyl-CoA dehydrogenases, acdA and acdB, arranged in tandem, were found in the chromosomal DNA of Acinetobacter sp. strain M-1. AcdA was purified from the parental strain and AcdB was purified from an Escherichia coli strain expressing the cloned gene. The substrate specificities of the two enzymes suggest that AcdA is a medium-chain acyl-CoA dehydrogenase and that AcdB is a long-chain acyl-CoA dehydrogenase. Characterization of n-alkane metabolism in Acinetobacter sp. strain M-1 has revealed parallel pathways as well as enzymes with overlapping specificities in a single pathway. The two acyl-CoA dehydrogenases described here provide another example of the physiological complexity underlying n-alkane utilization.

Journal Article↗