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Summary Spacing and kinship of the Formosan squirrel, Callosciurus erythraeus thaiwanensis, were studied in two different habitats. One, native habitat in the woods of Kenting, southern Formosa, was rich in available food throughout the year and had several species of predators. The other, a site in Kamakura, central Japan where squirrels had been introduced, had relatively scanty food and few potential predators. 1. Home ranges among males and between sexes overlapped extensively in both habitats. 2. Females occupied exclusive home ranges in Kamakura but had small overlapping home ranges in Ken-ting. 3. Most males disappeared from their natal areas at 1 year old in both habitats (86% in Kamakura and 93% in Ken-ting), but less females disappeared (36% in Kamakura and 35% in Ken-ting). 4. In Kamakura, daughters settled adjacent to the mother or inherited the home range of the mother, but never shared the mother's home range. In Ken-ting, 35% of daughters shared the home range with their mothers. 5. Tolerance among female kin in Ken-ting was probably facilitated by the richness of available food throughout the year, and functioned to reduce predation risk via alarm calling and mobbing. 相似文献
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Toshifumi Takao Noriko Tominaga Yasutsugu Shimonishi Saburo Hara Takashi Inoue Akio Miyama 《Biochemical and biophysical research communications》1984,125(3):845-851
A heat-stable enterotoxin was isolated and purified from the culture supernatant of by reversed-phase high-performance liquid chromatography. The amino acid sequence of the purified toxin was determined to be as follows: Gln-Ala-Cys(X)-Asp-Pro-Pro-Ser-Pro-Pro-Ala-Glu-Val-Ser-Ser-Asp-Trp-Asp-Cys-Cys-Asp-Val-Cys-Cys-Asn-Pro-Ala-Cys-Ala-Gly-Cys (X: not determined). The C-terminal sequence containing 6 half-cystine residues was highly homologous to that of heat-stable enterotoxin of enterotoxigenic 相似文献
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Purification and properties of pyridine nucleotide-independent L-lactate dehydrogenase from Polyporus circinatus 总被引:1,自引:1,他引:0 下载免费PDF全文
Cell extracts of Polyporus circinatus grown on lactate catalyze the reduction of 2,6-dichlorophenolindophenol by l-lactate without the participation of nicotinamide adenine dinucleotide or nicotinamide adenine dinucleotide phosphate. The enzyme has been purified 78-fold and was homogenous by disc gel electrophoresis. The optimal pH was found to be 6.7. The Michaelis constant for l-lactate was 5.9 x 10(-4) M and the oxalate inhibition constant was 1.5 x 10(-4) M. The nature of the prosthetic group is discussed. 相似文献
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One hundred and eighteen algal isolates comprising seven classes were obtained from a range of sites from polluted rivers running through Cu or Zn mining regions, and from unpolluted rivers. All the isolates were tested for photosynthetic activity when exposed to Cu, Cd or Zn. The tolerance levels of Bacillariophyceae, Charophyceae, Cyanophyceae and Chlorophyceae to Cu showed significant positive correlations with Cu concentrations in the field. However the distribution of metal sensitivities of the algae from the sites with the same metal concentration was broad. Both Bacillariophyceae and Charophyceae had a number of strains whose sensitivity to Cu differed more widely in relation to Cu levels in the environment than Cyanophyceae and Chlorophyceae. Cyanophyceae were sensitive to all three metals, whether or not isolates were obtained from polluted sites, whereas Chlorophyceae tended to have high tolerance even in isolates from unpolluted sites. For Cd and Zn the correlation between tolerance levels and concentrations in the field was not so clear as for Cu. The occurrence of Cu tolerance was shown in 4 diatom species and one Charophyceae, whereas metal resistance occurred in some Chlorophyceae. Cu-tolerant isolates tended also to be Zn-tolerant in Bacillariophyceae, and Cd-resistant isolates tended also to be Zn-resistant in Chlorophyceae. 相似文献
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Koichi Rikimaru Hitomi Toda Noriko Tachikawa Nobuyuki Kamata Shoji Enomoto 《In vitro cellular & developmental biology. Plant》1990,26(9):849-856
Summary A novel protein-free synthetic medium has been developed for the culture of human squamous cell carcinoma cells. This medium,
designated PF86-1, supports the serial subcultivation of six out of nine human squamous cell carcinoma cell lines in a protein-free,
chemically defined condition without the adapting culture from serum-containing conditions. These cell lines growing in PF86-1
exhibited nearly equal potency to grow in massive culture without noticeable changes in morphology but presented a significantly
decreased level of colony forming efficiency when compared with the cells cultured in serum-containing media, suggesting the
implication of some autocrine mechanism. Interestingly, this medium supported the growth of normal human squamous cells of
oral mucosa and skin for more than 2 mo. in the primary explant culture in spite of high levels of calcium ion concentration,
where the overgrowth of fibroblasts as contaminant was not observed. These results suggest that PF86-1 supports the growth
of cells derived from epidermal tissues selectively and provides the same defined condition for growth of malignant and nonmalignant
human squamous cells. It seems, therefore, that PF86-1 allows investigations on the products of squamous cell carcinoma cells
or on the differences of growth mechanisms between normal and neoplastic human squamous cells. 相似文献