Chemotactic activity of hemocytes derived from two marine neritid gastropod molluscs, Nerita albicilla and Heminerita japonica, to Vibrio parahaemolyticus and Escherichia coli strains.

Hemocytes of two marine neritid gastropods, Nerita albicilla and Heminerita japonica, were attracted chemotactically to live Vibrio parahaemolyticus and Escherichia coli strains. Chemotactic attraction of N. albicilla hemocytes was enhanced in the presence of N. albicilla plasma, while that of H. japonica hemocytes was not enhanced in the presence of H. japonica plasma. Chemotactic activity of the hemocytes seems to participate in the rapid elimination of V. parahaemolyticus from these gastropods.     

Plasma-dependent chemotactic activity of hemocytes derived from a juvenile estuarine gastropod mollusc, Clithon retropictus, to Vibrio parahaemolyticus and Escherichia coli strains.

Hemocytes of adult Clithon retropictus were attracted chemotactically to live Vibrio parahaemolyticus and Escherichia coli strains. The chemotaxis was stimulated by the plasma of adult C. retropictus. Hemocytes of the juvenile specimen were attracted chemotactically to V. parahaemolyticus and E. coli strains in the presence of the plasma of the juvenile and only to E. coli strain in the absence of the plasma. These evidences suggest that hemocytes of juvenile C. retropictus might be defective to recognize V. parahaemolyticus strains and that the hemocytes would display full activities in the presence of the plasma factor(s).     

Detection of aflatoxin B1 in imported food products into Japan by enzyme-linked immunosorbent assay and high performance liquid chromatography.

In order to detect the presence of aflatoxin B1 (AFB1), the use of the enzyme-linked immunosorbent assay (ELISA) and recovery test was evaluated. The detection limit of ELISA for AFB1 was 1 pg/assay and the recovery from maize spiked with AFB1 exceeded 80%. AFB1 was detected by ELISA in seven out of twelve samples of imported food products including peanut, almond, red pepper, cocoa bean, black pepper, buckwheat, walnut, adlay, soybean, popcorn, and pistachio nut, and by high performance liquid chromatography (HPLC) in four of the samples. However, the content of AFB1 in these samples was less than 10 ng/g of the minimum value authorized by the Japanese sanitation law. These results demonstrate that ELISA is more sensitive than HPLC and imported food products are broadly contaminated with AFB1.     

In vitro attachment of Vibrio parahaemolyticus to hemocytes of two gastropod molluscs.

Vibrio parahaemolyticus D-3 was observed to attach to hemocytes of a marine gastropod mollusc, Nerita albicilla, regardless of the presence of N. albicilla serum. The organism attached to hemocytes of an estuarine gastropod, Clithon retropictus, in the presence of C. retropictus serum while the attachment to the hemocytes was decreased significantly in the absence of the serum. These evidences suggest that N. albicilla hemocytes would facilitate the clearance of V. parahaemolyticus from the alimentary tract of the mollusc and that C. retropictus hemocytes would protect C. retropictus against the invasion of V. parahaemolyticus to hemocoel of the mollusc.     

Investigations on the radioactive contamination of crop plants as a result of H-bomb detonation (Part 1) Radioactive contamination of crop plants and soils

Since radioactive rain-out covered Japan in March-May 1954, due to the H-bomb detonation at Bikini atoll, the authors started assaying the possibie radioactive contamination of crop plants grown at Tokyo district.     

Asparagine test in relation with the nitrogen nutritional status of crop plants III

During the course of the previous studies (1, 2) of this series dynamics of asparagine appearance in crop plants was investigated and it was found that its appearance has, definitely, direct relation with the nitrogen nutritional status of crop plants. It was also clarified that its appearance is initiated, mostly, by the starting of the panicle formation and the resultant breaking down and transportation of complex nitrogenous compounds. The simultaneous study of asparagine and nitrate appearance revealed that the nitrate has no direct relation with the panicle formation and asparagine appearance. In the first experiment on rice, we did not try nitrate test together with the asparagine test. The surface layer (less than 1 cm) of the rice soil, even in the waterlogged condition gets oxidised gradually and nitrogen exists mainly as nitrate. Moreover, there has been some mention that the rice roots possess an oxidative atmosphere (3,4,5) around it and soils having less amount of easily decomposable organic matter or high water percolating capacity do not get completely reduced under waterlogging, it is supposed that nitrate which is by nitrification from ammonia may appear specially around the roots. It seemed necessary to include nitrate test in this experiment along with the asparagine test. In addition, to study the role of different sources of nitrogen towards the appearance of asparagine, the experiment was designed to have provision of topdressing in the NH⁴, NH⁴+NO³, NO³ and urea forms. It is expected that the result on the topdressing would bring more and more practicality to the asparagine test.