Distribution and Recent Reduction of Gelidium Beds in Toyama Bay, Japan

The distribution and recent reduction of Gelidium beds, i.e. mat-like beds dominated by the agarophyte G. elegans Kützing in Toyama Bay (Sea of Japan), in which 95% of the coastline is protected artificially, are reported. Gelidium beds were common in shallow waters (usually < 10 m deep); most of the large beds (> 1 ha) were restricted to the inner coasts of the bay. In calm and eutrophic areas, however, G. elegans was heavily colonized by epiphytes. In the last decade, two beds were buried in situ and beds in their vicinity were damaged by the stagnation of coastal water and/or sedimentation by silts which accompanied land reclamation. At the other two beds monitored since 1988, Gelidium declined a few times but most prominently in 1998, when episodic long summer rain was recorded. This is the first report, not only on the current status of Gelidium beds other than for the central Pacific Coast of Honshu in Japan, but also concerning reduction of the beds caused by both anthropogenic and natural events.     

Partial Asymmetric Synthesis in α-Alkylation of Enamine with Electrophilic Olefin

About 30 dipeptides and some tripeptides were led to new benzimidazole derivatives by incorporating their carboxyl groups into benzimidazole ring by the reaction with o-phenylenediamine. The ring closure to benzimidazole was well achieved by heating mildly at a moderate temperature in acetic acid.

Some benzimidazole derivatives of peptides had remarkable phytotoxicities.     

I-Region genetic restrictions imposed upon the recognition of KLH by murine T-cell clones

Data presented in this paper show that the recognition of keyhole limpet hemocyanin by murine T-cell clones is restricted by products of the I region. These data have been obtained by genetic mapping studies as well as by the use of monoclonal la-specific antibodies which inhibit the ability of antigen-presenting cells to effectively present antigen to such T-cell clones. Use of heterozygous antigen-presenting cells derived from crosses between B6.C-H-2 ^bm12 and B10.A(4R) mice have allowed us to show that both trans-complementing I-A products are used for restriction of recognition of KLH. These data were confirmed using monoclonal Ia antibodies to inhibition recognition of KLH by the same T-cell clones. Thus, we have shown that there exist hybrid molecules formed by free combinatorial association of products encoded within the I-A subregion which restrict the recognition of soluble antigen. Additionally, we have shown that the molecule formed by complementation between the alpha chain encoded within the I-E region and a beta chain encoded within the A region (A_e) can function effectively in presenting KLH to certain murine T-cell clones. These results support the hypothesis that the recognition of individual antigenic epitopes within large multideterminant antigens is under the control of Ir genes.     

Isolation and Partial Characterization of the Major Seed Protein from Nicotiana tabacum,and Accumulation during Development

During the seed development of Nicotiana tabacum, appreciable accumulation of the soluble protein fraction started to occur at around the 6th day after anthesis and finally reached 12% on the basis of dry weight when seed maturation was accomplished. In the soluble fraction of mature seeds, four protein fractions were observed on analytical ultracentrifugation, and the protein having a sedimentation coefficient of 11.7S was the major one. The 11.7S protein was isolated and SDS-polyacrylamide gel electrophoresis indicated that the protein consisted of at least five subunits with molecular weights of 49,000, 31,000, 29,000, 21,000 and 19,000. The 11.7S protein was rich in glutamic acid or glutamine and arginine, and the presence of carbohydrate was confirmed.

During development, all of the five subunits started to appear during the period between the 12th and 15th day after anthesis.