Analysis of the sexual development-promoting region of Schizophyllum commune TRP1 gene.

This study aims to elucidate the mechanism of sexual development of basidiomycetous mushrooms from mating to fruit body formation. Sequencing analysis showed the TRP1 gene of basidiomycete Schizophyllum commune encoded an enzyme with three catalytic regions of GAT (glutamine amidotransferase), IGPS (indole-3-glycerol phosphate synthase), and PRAI (5-phosphoribosyl anthranilate isomerase); among these three regions, the trp1 mutant (Trp(-)) had a missense mutation (L→F) of a 338th amino acid residue of the TRP1 protein within the IGPS region. To investigate the function of IGPS region related to sexual development, dikaryons with high, usual, and no expression of the IGPS region of TRP1 gene were made.

Isolation of novel bacteria and actinomycetes using soil-extract agar medium.

Novel bacteria were discovered using an isolation technique consisting of (i) selection of microorganisms that grew on soil-extract agar medium, but not on conventional media, and (ii) detection of small microbial colonies with a microscope. Three bacterial strains thus isolated were provisionally designated Shinshu-th1, -th2, -th 3, and five actinomycete strains, Shinshu-MS-01, -02, -03, -04, -05, respectively. Sequence analysis of their 16S rDNA showed that th1 had 95--96% homology with three unculturable bacteria, and th2 had 96% similarity to Bradyrhizobium sp.

Rare bacterium of new genus isolated with prolonged enrichment culture.

Dynamic change in microbial flora was monitored with an oxygen electrode. The 1st phase microorganisms, which first grew well in LB medium, were followed by the 2nd phase microorganisms, which supposedly assimilated microbial cells of the 1st phase and their metabolites. In a similar way, a change in microbial flora was observed from the 1st phase to the 4th phase in 84 hr.

Effects of indole and caffeine on cAMP in the ind1 and cfn1 mutant strains of Schizophyllum commune during sexual development.

The ind1 and cfn1 mutations of Schizophyllum commune express resistance to high concentrations of indole and caffeine respectively, and also affect sexual development. To clarify molecular events caused by the mutations, it was investigated how cAMP levels in S. commune strains respond to externally supplied indole and caffeine.

Activities of Mesoderm-Inducing Factors Secreted by Mammalian Cells in Culture : (mesoderm-induction/activin A/EDF/TGF-β family/embryonic induction).

We have examined the activities of several mesoderm-inducing factors contained in the culture fluids of phorbol ester (4beta-phorbol 12-myristate 13-acetate;PMA)-stimulated human cell lines. Mesoderm induction was assayed by examining the differentiation of mesoderm tissues reacted with presumptive ectoderm of the Cynops blastula. The assay system also examined erythroid differentiation activity (EDF activity) in order to test the relationship between mesoderm induction and activin A (EDF).

Mesodermal induction in early amphibian embryos by activin A (erythroid differentiation factor).

Recently the mesoderm-inducing effects of the transforming growth factor β (TGF-β) family of proteins have been widely examined. In an attemt to elucidate the functions of these proteins, porcine inhibin A and activin A (erythroid differentiation factor; EDF) were examined. Treatment of explants with activin A led to differentiation of mesodermal derivatives such as mesenchyme, notochord, blood cells and muscle, but inhibin A had a much lesser effect.

Significance of an Increase of Intracellular Adenosine Concentration for Dormancy in Starfish Blastulae: (starfish embryos/blastula/adenosine/dormancy).

Adenosine at concentrations greater than 6 μg/ml halted embryonic development of the starfish Asterina pectinifera specifically at the 256-cell stage which corresponds to the onset of blastulation. When a fertilized egg was cultured continuously in sea water containing adenosine from fertilization, a gradual increase in intracellular concentrations of free adenosine was observed before a cessation of development took place. On the other hand, intracellular concentrations of ATP, ADP and AMP in the embryo cultured in sea water containing adenosine were nearly the same as those of an embryo cultured in sea water without adenosine.