Biomedical subjects

Noboru Takiguchi

Publications and source records attributed to Noboru Takiguchi.

22 records · Page 2Linked to original sources

PubMed2002

Accumulation of inorganic polyphosphate in phoU mutants of Escherichia coli and Synechocystis sp. strain PCC6803.

The biological process for phosphate (P(i)) removal is based on the use of bacteria capable of accumulating inorganic polyphosphate (polyP). We obtained Escherichia coli mutants which accumulate a large amount of polyP. The polyP accumulation in these mutants was ascribed to a mutation of the phoU gene that encodes a negative regulator of the P(i) regulon. Insertional inactivation of the phoU gene also elevated the intracellular level of polyP in Synechocystis sp. strain PCC6803. The mutant could remove fourfold more P(i) from the medium than the wild-type strain removed.

Bacterial Proteins↗

PubMed2002

Cloning and characterization of extracellular metal protease gene of the algicidal marine bacterium Pseudoalteromonas sp. strain A28.

The gene (empI) encoding an extracellular metal protease was isolated from a Pseudoalteromonas sp. strain A28 DNA library. The recombinant EmpI protein was expressed in E. coli and purified. Paper-disk assays showed that the purified protease had potent algicidal activity. A skim milk-polyacrylamide gel electrophoresis protease assay showed that the 38-kDa band of protease activity, which co-migrated with purified EmpI and was sensitive to 1,10-phenathroline, was detected in the extracellular supernatant of A28.

Cloning, Molecular↗

PubMed2002

Isolation and characterization of cbbL and cbbS genes encoding form I ribulose-1,5-bisphosphate carboxylase/oxygenase large and small subunits in Nitrosomonas sp. strain ENI-11.

The cbbL and cbbS genes encoding form I ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) large and small subunits in the ammonia-oxidizing bacterium Nitrosomonas sp. strain ENI-11 were cloned and sequenced. The deduced gene products, CbbL and CbbS, had 93 and 87% identity with Thiobacillus intermedius CbbL and Nitrobacter winogradskyi CbbS, respectively. Expression of cbbL and cbbS in Escherichia coli led to the detection of RubisCO activity in the presence of 0.1 mM isopropyl-beta-D-thiogalactopyranoside (IPTG). To our knowledge, this is the first paper to report the genes involved in the carbon fixation reaction in chemolithotrophic ammonia-oxidizing bacteria.

Ammonia↗

PubMed2002

Behavioral responses of the ciliated protozoan Paramecium caudatum to 2,4-dichlorophenoxyacetic acid and its analogues.

We found that the ciliated protozoan Paramecium caudatum ON-1 was repelled by 2,4-dichlorophenoxyacetic acid (2,4-D). P. caudatum was also repelled by phenoxyacetic acid, while it was attracted to benzoic acid. No significant behavioral response was detected with 2,4-dichlorophenol (2,4-DP) and phenol. These results suggested that the substitution of-OH of phenol with -OCH2COOH, but not the chlorination of phenol, was important for eliciting the avoiding response to 2,4-D in P. caudatum. Electrophysiological analysis revealed that 2,4-D and phenoxyacetic acid were able to trigger the action potential in P. caudatum, whereas 2,4-DP and phenol failed to elicit electrical responses in this organism. Well test assays suggested that the avoiding reactions allowed P. caudatum to escape from the harm caused by this herbicide.

Journal Article↗