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Biomedical subjects

A Kiba

Publications and source records attributed to A Kiba.

7 recordsLinked to original sources
PubMed2003

Overexpression of Bax inhibitor suppresses the fungal elicitor-induced cell death in rice (Oryza sativa L) cells.

Treatment of suspension-cultured cells of rice (Oryza sativa L.) with cell wall extract of rice blast fungus (Magnaporthe grisea) elicits a rapid generation of H2O2, alkalinization of culture medium, and eventual cell death. To elucidate genes involved in these processes, we exploited SAGE (Serial Analysis of Gene Expression) technique for the molecular analysis of cell death in suspension-cultured cells treated with the elicitor. Among the downregulated genes in the elicitor-treated cells, a BI-1 gene coding for Bax inhibitor was identified. Transgenic rice cells overexpressing Arabidopsis BI-1 gene showed sustainable cell survival when challenged with M. grisea elicitor. Thus, the plant Bax inhibitor plays a functional role in regulating cell death in the rice cell culture system.

Apoptosis↗
PubMed2001

Production of antimicrobial defensin in Nicotiana benthamiana with a potato virus X vector.

A recombinant plasmid, pTXS.TH, was constructed to express the gene-encoding wasabi (Wasabia japonica) defensin with the potato virus X (PVX) vector. pTXS.TH allows the expression of defensin in the host Nicotiana benthamiana, and the defensin protein WT1 can be purified from virus-infected leaves by heat treatment and affinity chromatography. WT1 exhibits strong antifungal activity toward the phytopathogenic fungi Magnaporthe grisea (50% inhibitory concentration [IC50] = 5 microg/ml) and Botrytis cinerea (IC50 = 20 microg/ml) but is weakly active against the phytopathogenic bacterium Pseudomonas cichorii. This virus-mediated expression system is a rapid and efficient method to produce and characterize antimicrobial proteins in plants. It is particularly useful for the study of proteins that are difficult to produce with other expression systems.

Anti-Infective Agents↗
PubMed1999

The role of Xmsx-2 in the anterior-posterior patterning of the mesoderm in Xenopus laevis.

Many molecules are involved in defining mesodermal patterning of the Xenopus embryo. In this paper, evidence is provided that a member of the msx family of genes, the Xmsx-2 gene, is involved in anterior-posterior patterning of the mesoderm. A comparison of its sequence to another previously cloned msx-2 Xenopus homolog, Xhox-7.1' [45] showed that they are closely related. The Xmsx-2 gene is first expressed at midgastrulation predominantly in the dorsal part of the embryo. It showed a complex pattern of spatial expression, consistent with a role in patterning of the anterior-posterior axis. This inference is confirmed by gain-of-function experiments in which overexpressed msx-2 mRNA in developing Xenopus embryos resulted in embryos lacking anterior structures. Analysis of markers in mutant embryos showed that genes involved in ventral-posterior patterning such as Xhox-3, Xwnt-8, and Xvent-1 were upregulated, confirming the posteriorized nature of the embryos. We believe that the Xmsx-2 gene is involved in refining the patterning of the anterior-posterior part of the dorsal mesoderm after the initial signals determining the dorsal or ventral nature of the mesoderm have been specified.

Amino Acid Sequence↗
PubMed1999

Induction of defense responses by synthetic glycopeptides that have a partial structure of the elicitor in the spore germination fluid of Mycosphaerella pinodes.

A high molecular weight elicitor (> 70 kDa) from spore germination fluid of a pea pathogen, Mycosphaerella pinodes, has a partial structure of beta-D-Glc-(1-->6)-alpha-D-Man-(1-->6)-D-Man, which is O-glycosidically attached to serine in the protein moiety. To elucidate the minimum structure for the elicitor activity to pea plants, the effects of nine glycopeptides including beta-D-Glc-(1-->6)-alpha-D-Man-(1-->6)-D-Man-O-Ser (No. 1) to [beta-D-Glc-(1-->6)-alpha-D-Man-(1-->6)-D-Man]3-O-Ser3-Pro3 (No. 9) on the infection by M. pinodes, superoxide generation and ATPase activity were measured. The glycopeptides [beta-D-Glc-(1-->6)-alpha-D-Man-(1-->6)-D-Man]-O-Ser2-Pro2 (No. 3) to No. 9 induced rejection reaction of pea tissue against M. pinodes. The glycopeptides No. 3 to No. 9 also induced superoxide generation on uninjured pea leaves. Moreover, the glycopeptides No. 3 to No. 9 induced in vitro the activation of cell wall-bound ATPase and superoxide generation system in the protein fraction solubilized from pea cell wall. The results indicate that the synthetic glycopeptides, No. 3 to No. 9, are available to analyze the signal transduction cascade leading to defense responses and the receptor for the elicitor.

Amino Acid Sequence↗