Hexane soluble non-volatiles in flowering to fruiting stages of Fatsia japonica

The n-hexane soluble non-volatile fraction of the acetone extracts from the flower buds, the flowers and the immature and the mature fruits of Fatsia japonica were all found to contain fatty acids, fatty acid methyl esters, squalene, β-amyrin and sterols. At all the stages between budding to the mature fruit, the major fatty acids were palmitic and linoleic acids and the major phytosterol was stigmasterol. In addition steryl and β-amyrenyl esters were found in the flowers and the immature and the mature fruits, but these esters were not present in the flower buds. Sitosteryl ester was the major constituent of the steryl ester fraction in the fruiting stages. Phytol was found in only the flowering stage and triglycerides in only the mature fruits. The variations in the lipid constituents is discussed in relation to the stages from budding to the mature fruit.     

Light regime in relation to plant population geometry

A beam-emission experiment using a Monte Carlo technqiue was attempted in a computer model for the random distribution (RD) of foliage. The RD foliage consisted of 500 leaves of the same size, their individual areas being just 1/100 of the unit land area; i.e., a leaf area index (LAI) of RD foliage was equal to 5. Satisfactory agreement of light transmission under a uniform overcast sky was obtained between the observed values in the RD foliage and theoretical anticipations for any leaf inclination angle and/or leaf area density. This result demonstrated the usefulness of the Monte Carlo technique adopted in this experiment. The Monte Carlo experiment was also applied to a patch-like population. For such a foliage, additional effect of lateral incidence were worth noting in contrast with the microclimates in the corresponding infinite foliage. For every leaf inclination angle the mean light flux density below the middle stratum within a patch-like population was not further attenuate with increasing LAI.     

A specific heterotypic cell adhesion activity between members of carcinoembryonic antigen family, W272 and NCA, is mediated by N-domains

The Ca(2+)-independent homotypic and heterotypic cell adhesion activities of a carcinoembryonic antigen (CEA) family member, W272 (CGM6), whose cDNA has recently been isolated from libraries of human peripheral leukocytes of apparently normal subjects (Arakawa, F., Kuroki, Mo., Misumi, Y., Oikawa, S., Nakazato, H., and Matsuoka, Y. (1990) Biochem. Biophys. Res. Commun. 166, 1063-1071) and spleen of chronic myelogenous leukemia patients (Berling, B., Kolbinger, F., Grunert, F., Thompson, J. A., Brombacher, F., Buchegger, F., von Kleist, S., and Zimmermann, W. (1990) Cancer Res. 50, 6534-6539) has been examined. Chinese hamster ovary cells transfected with the cDNA for W272, CEA, nonspecific cross-reacting antigen (NCA), and various antigens containing chimeric N-domain have been used. The W272 producers did not show homotypic binding at all but bound only to the cells expressing NCA and a chimeric CEA whose N-domain is substituted by that of NCA, indicating the major contribution of N-domain of NCA in the specific binding. The importance of the N-terminal region of NCA N-domain for the W272-NCA binding has been shown by detailed analysis using COS-1 cells producing various NCA whose N-domain are chimera of that of NCA and CEA. The strict heterotypic nature of the W272-NCA adhesion strongly suggests that the cell adhesion activities exhibited by CEA family members are not the fortuitous activity but the specific one which have some important physiological roles.     

Growth requirements and long-term subcultivation of bovine granulosa cells cultured in a serum-free medium

Summary We have developed an improved serum-free medium to optimize the cell growth of bovine granulosa cells. The cells on collagen-coated culture plates proliferated extensively in a nutrient medium supplemented with insulin, heparin binding growth factor-2 (HBGF-2), lipoprotein, and bovine serum albumin (BSA). The cell doubling time at logarithmic phase and final cell density at confluent cultures were equal to those of cultures grown in the presence of medium supplemented with optimal concentration (10%) of fetal bovine serum (FBS). Whereas HBGF-2 or insulin alone had a small mitogenic effect of granulosa cells, lipoprotein or BSA did not. When lipoprotein, BSA, or insulin was added together with HBGF-2, synergistic cell proliferation was observed in all combinations. Insulin or lipoprotein had an additive mitogenic stimulation of these cells in the presence of BSA. After granulosa cells were subcultivated in a serum-containing medium until three generations [8.5 cumulative population doubling level (CPDL)], subsequent subcultivation of the cells in a complete serum-free medium could be achieved up to six generations (14.4 CPDL). These results demonstrate that this serum-free medium can support the optimal cell growth and long-term subcultivation of bovine granulosa cells.     

Immunocytochemical studies on the pancreatic endocrine cells in the Japanese newt (Cynopus pyrrhogaster)]

Pancreatic endocrine cells were examined by light and electron microscopic immunocytochemistry to discuss the co-localization of peptides in one cell type. A cells were irregular in shape with an occasional long cytoplasmic process, and contained glucagon-immunoreactive granules with various contours. These granules were 160-300nm in diameter with various density, and also immunoreactive to anti-human pancreatic polypeptide (PP) serum. A part of them were further immunoreactive to anti-somatostatin serum. B cells were round to elliptical in shape, and often aggregated around the capillaries. Granules of B cells were round to irregular in shape, 270-410 nm in diameter, and immunoreactive to anti-insulin serum. D cells were irregular in shape with meager cytoplasm, and contained somatostatin-immunoreactive granules. These granules were ovoid or teardrop in shape, 140-250nm in longitudinal diameter, and immunoreactive to both anti-somatostatin and anti-human PP sera. PP cells were round to spindle-shaped, and contained human PP-immunoreactive round granules 150-35nm in diameter. These findings reveal the existence of at least 4 types of endocrine cells secreting glucagon, insulin, somatostatin, and PP, respectively, in the newt pancreas, and suggest the co-localization of some of these peptides in one cell type.     

Impact of whitefish on an enclosure ecosystem in a shallow eutrophic lake: changes in nutrient concentrations,phytoplankton and zoobenthos

Large bag-type (75 m³) and tube-type (105 m³) enclosures were set up in the shallow eutrophic Lake Suwa and were each stocked with exotic planktivorous whitefish (Coregonus lavaretus maraena). The release of whitefish caused the increase in nutrient concentration in the tube-type enclosure whereas no such increase was observed in the bag-type enclosure. Bottom sediment seemed to be an important source of chironomid food for whitefish. The proportion of phytoplankton measuring<10μm and 20–40μm, which respectively corresponded toOchromonas spp. andCryptomonas sp., were lower in the fish enclosures than in the control, which might have been caused by high grazing pressure by rotifers. The predation by whitefish might have affected the species composition of phytoplankton through reducing copepod predation on rotifers, not through reducing the densities of cladocerans which directly feed on phytoplankton as many investigators have reported. The phytoplankton biomass was not affected much by the release of fish. Possible reasons are that the increase in density of rotifers reduced the biomass of available phytoplankton and also that inedible Cyanophyceae were in the decreasing phase of their seasonal succession and could not increase successfully in spite of elevated nutrient levels.     

Impact of whitefish on an enclosure ecosystem in a shallow eutrophic lake: selective feeding of fish and predation effects on the zooplankton communities

Bag-type enclosures (75 m³) with bottom sheets and tube-type enclosures (105 m³) open to the bottom sediment were stocked with exotic whitefish (Coregonus lavaretus maraena) to study their predation effects on the plankton community. The fish fed mainly on adult chironomids during the period of their emergence (earlier part of the experimental period). Thereafter, the food preference was shifted to larvae of chironomids and crustacean zooplankters. The predation effects on the plankton community were not evident in the bag-type enclosures where zooplankton densities were consistently low. The fish reduced the crustacean populations composed ofBosmina fatalis, B. longirostris andCyclops vicinus in the tube-type enclosures where the prey density was high (above ca. 50 individuals 1⁻¹). The results suggested that the intensity of predation depended on the prey density. Rotifers increased in the fish enclosure, probably becauseCoregonus reduced the predation pressure byCyclops vicinus on rotifers and allowed the latter to increase. In the fish enclosures, no marked changes in species composition were observed. Zooplankton predated by the fish seemed to be distributed near the walls of the enclosures. Problems of enclosure experiments for examining the effects of fish predation on pelagic zooplankton communities are discussed.