Zoogeographical aspects of rocky-intertidal molluscan fauna of the Pacific coasts of Japan

Intertidal molluscan faunas were studied on the exposed rocky shores of the Pacific coasts of Japan (excluding Hokkaido) to determine distribution patterns and latitudinal gradients of taxa. Collections were made at spring low tide in 1980. Five types of distribution patterns were found: tropical, tropical-temperate, warm-temperate, temperate, and boreal. Many examples of parallel species displacement, the term which Thorson (1957) proposed and generalized, were found. Latitudinal gradients of molluscan taxon were observed. Frequency of the Archaeogastropoda in gastropods increases northward, while frequency of the Mesogastropoda and the Neogastropoda decreases. Frequency of predatory gastropods decreases northward, and that of herbivorous ones increases. Commonness indices show that the molluscan fauna of the study sites situated within the wide area between the Kanto and Kyushu are closely related with each other, and they can be regarded as one province. The Tohoku district is less related with this region, and the Okinawa district is the least related.     

Relationship between the growth and survival of larval Pacific bluefin tuna, Thunnus orientalis

We tested the hypothesis that a large body size and rapid growth rate affect the survival of larval Pacific bluefin tuna, Thunnus orientalis (PBT), and analyzed larval growth in relation to environmental conditions. Seven high density larval patches of PBT were tracked with reference buoys in the northwestern Pacific Ocean for 28–171 h in May–June from 2004 to 2008. The otolith radii and daily growth rates of the survivor larvae (collected on later tracking days of each tracking session) tended to be larger and more rapid, respectively, than those of original larvae (collected on earlier tracking days). A large body size was found to positively affect the survival of larval PBT, as did a rapid growth rate, even at an early larval stage (7 days after hatching). Generalized linear modeling showed that the otolith radius was influenced positively by the sea temperature, stratification parameter and food density, while the growth rate was influenced positively by the sea temperature and food density.     

Do bumble bee queens choose nest sites to maximize foraging rate? Testing models of nest site selection

We proposed “foundress-max” hypothesis that a bumble bee foundress chooses her nest site to maximize her energy intake rate from nectar. To examine the hypothesis, we estimated the maximum energy intake rate at each site in the study area and compared the distribution of the maximum energy intake rates with those of actual nest sites. We also calculated rank correlations of the maximum energy intake rate with the number of nest-searching foundresses at 54 sites. The nest locations supported the foundress-max hypothesis, but the number of nest-searching foundresses did not. This could be attributed to the density of food sites: many food sites may attract many foundresses. Therefore, we subsequently proposed “foundress-sum” hypothesis that a foundress chooses her nest site to maximize the sum of energy intake rates. The nest locations supported the foundress-max hypothesis more than the foundress-sum hypothesis. A profitable food site would affect foundresses’ nest site selection.     

Cadmium,copper, and zinc in carrots in Japan

Cadmium (Cd), copper (Cu), and zinc (Zn) in carrots obtained from different regions throughout Japan were assessed in a baseline study on the contents of trace metals in foods. These three metals were measured by flameless atomic absorption spectrophotometry. The geometric mean contents (with one geometric standard deviation indicated in parentheses) of Cd, Cu, and Zn were 0.02 (2.2), 0.7 (2.1), and 2.4 (1.6) mg?kg^?1 wet weight in carrots obtained in Japan. While there was a close relationship among the contents of the three metals in the carrots grown in Cambisols and Gleysols, a significant relationship was recognized only between the contents of Cd and Zn in those grown in Andosols and Fluvic Gleysols. Cd and Zn are classified as 2B metals in the periodic table of elements, and the authors speculate that the similarity of the metal characteristics between Cd and Zn may be responsible for the close relationship in the contents of the two metals, with no relation to the soil type.     

Immunoblot detection of enzyme proteins of peroxisomal β-oxidation in fibroblasts,amniocytes, and chorionic villous cells. Possible marker for prenatal diagnosis of Zellweger's syndrome

The amounts of enzyme proteins of peroxisomal β-oxidation in fibroblasts and chorionic villous cells from infants with Zellweger syndrome and in fibroblasts, amniocytes, and chorionic villi from healthy controls were measured by immunoblot analysis. Immunoreactive proteins of peroxisomal acyl-CoA oxidase and 3-ketoacyl-CoA thiolase were absent in fibroblasts and chorionic villous cells from the patients, yet these enzyme proteins were present in fibroblasts, cultured amniocytes, and chorionic villi from the normal controls. These results show that immunoblot analysis of peroxisomal β-oxidation enzymes in amniocytes and chorionic villous cells is of potential value for the prenatal detection of Zellweger syndrome.     

Photochemical nitrosation of dimethylamine in aqueous solution containing nitrite

Dimethylamine was found to be nitrosated photochemically in aqueous solution containing nitrite both by the irradiation with a high pressure mercury lamp and by the exposure to sunlight to give nitrosodimethylamine, a well-known carcinogen. The nitrosation occurred more readily at alkaline pH than at acidic and neutral pH. These findings suggest that nitrosodimethylamine is produced photochemically under natural environmental conditions.