Germination stimulant from root exudates of Vigna unguiculata

Root exudate of Vigna unguiculata was extracted from a soil system consisting of charcoal and vermiculite. Germination stimulating activity for Striga gesnerioides was found in extracts of the soil system, and an active compound was isolated. The chemical structure of the active ingredient was determined to be (+)-4-O-acetylorobanchol, based on analysis of the spectral data of 1-D and 2-D NMR together with nuclear Overhauser effect (NOE) experiments. Application of the active compound to the seeds of S. gesnerioides at a concentration of 0.35 × 10⁻⁹ mol/disk led to 69% germination. The germination observed with application of GR-24, a positive control, at 0.57 × 10⁻¹⁰ mol/disk was 80%.     

Virulence phenotypes of Shigella flexneri 2a avirulent mutant 24570 can be complemented by the plasmid-coded positive regulator virF gene

Avirulent mutation of an opaque colony variant of Shigella flexneri 2a designated 24570 has been believed to be linked with the glpK locus of the chromosome. However, avirulent phenotypes of the 24570 strain could be complemented by the invasion plasmid-coded virF gene, a positive regulator for invasion genes. The 24570 strain had a DNA structural alteration upstream of the virF gene.     

Interactions of microorganisms with rare earth ions and their utilization for separation and environmental technology

In recent years, rare earth elements (REEs) have been widely used in various modern technological devices and the global demand for REE has been increasing. The increased demand for REEs has led to environmental exposure or water pollution from rare earth metal mines and various commercial products. Therefore, the development of a safe technology for the separation and adsorption of REEs is very important from the perspective of green chemistry and environmental pollution. In this review, the application and mechanisms of microorganisms for the removal and extraction of REEs from aqueous solutions are described. In addition, the advantages in using microorganisms for REE adsorption and future studies on this topic are discussed.     

Synthesis and Secretion of Acid Phosphatase in Halotolerant Zygosaccharomyces rouxii

Changes in the contents of defensive substances against the active oxygen in water-stressed spinach plants were examined. The contents of ascorbate peroxidase (AP; EC 1.11.1.7), glutathione reductase (GR; EC 1.6.4.2) and α-tocopherol increased remarkably in water-stressed spinach leaves, while those of Superoxide dismutase (SOD; EC 1.15.1.1), dehydroascorbate reductase (EC 1.8.5.1), ascorbate and glutathione changed little. The content of α-tocopherol in chloroplast thylakoid membranes isolated from water-stressed leaves was higher than that from normal leaves. It is, therefore, conceivable that GR, AP and α-tocopherol might be related to the tolerance of plants to water deficiency.     

Isolation and Biological Activity of Cyl-2, a Metabolite of Cylindrocladium scoparium

Three metabolites designated Cyl–1, –2 and –3 were isolated as plant growth regulators from culture filtrate of Cylindrocladium scoparium Morgan, a phytopathogenic fungus. Cy1–2 was obtained as pure crystals, and it revealed marked inhibitory activity on the root growth of lettuce seedlings. Cyl–1 showed inhibition on the same organ, while Cyl–3 showed promotion.     

Synthesis and Bioactivity of Novel Acetylenic Compounds

The synthesis of novel acetylenic ketone compounds and anti-inflammatory and antimicrobial activities are herein described.     

Polarographic Behavior of Thiolated Natural and Synthetic Polymers

Polarographic protein waves were studied by using model samples. Two samples were prepared by thiolation of natural and synthetic polymers which show no catalytic wave in the ammoniacal cobalt buffer. The one was made from bacterial α-amylase by thiolation with N-acetylhomocysteine and the other was made from polyvinylalcohol by esterification with thioglycolic acid. These thiolated polymers showed typical double waves similar to protein waves both in cobaltous and cobaltic media though minute differences were present between the waves of thiolated polyvinylalcohol and those of proteins.     

On the Activity of Alkaline Phosphatase in Intestinal Mucosa from Casein-fed Rats

A novel optical activity of lutein was studied in dodecyltrimethylammonium bromide (DTAB) solution by the measurement of circular dichroism and absorbance. The surfactant was found to bring about the circular dichroism activity of the lutein below the critical micelle concentration (CMC) in a different way from that by sodium dodecyl sulfate (SDS). This phenomenon was interpreted by the card-pack model of the lutein aggregate in which lutein molecule was slightly shifted each other. The above optical activity abruptly became strong just before the CMC of DTAB. This seems to correspond to the transition from the polymeric aggregate of the lutein to the oligomeric one. Such an optical activity disappeared beyond the CMC on the incorporation of the lutein molecules into the surfactant micelles. The molar binding ratios of DTAB to the lutein were determined to be 130 to 210 on the basis of the lutein concentration dependence of the DTAB concentration showing the arbitrary ellipticity. These ratios were clearly larger than those for SDS. On the other hand, filtration measurement showed that the size of the lutein-DTAB complex was larger than 2 μm in diameter. These phenomena were discussed assuming the possible model of the aggregate as a comparative study of the anionic and cationic surfactants causing the novel optical activity of this aggregate.