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991.
Estimation of the number of adult grasshoppers, Mecostethus magister, was made by means of the mark-and-recapture method. The birth and death rates are possible to be estimated at the same time, but the immigration and the emigration rate are inevitably involved in these respectively. The immigration and emigration rates must be made clear to know the true birth and death rates. For this purpose the movement of the marked males in 1963 was analyzed. The grasshoppers dominantly moved in the directions of N, NW and W, and the difference in frequency among the movement directions was not so large. The distribution of the dispersal-distance relationship of each quadrate on each released day was fitted approximately to normal distribution. It could be concluded that almost all of the grasshoppers moved within the range of about 31–35m. The emigration rate from the quadrate (12×12m2) was about 0.73–0.77 and the difference in the rate among the released days was small. From these values the emigration rate from the station (84×60m2) was estimated as 0.21–0.23. Subtracting the emigration rate from the death-and-emigration rate, the true death rate was calculated. The death rate was very low until the number of males reached to the peak, then increased gradually. Supposing that immigration rate was equal to the emigration rate, the true birth rate was also estimated. But the presumption might not be pertinent, for the value of birth rates became negative. 相似文献
992.
993.
Summary As is expected, a fast growing mutant on casein medium produced larger amount of protease than its parent or sister cultures. As a rule, the mutant yielded protease in a later stage of growth in contrast to its sister strain which produced it at an earlier stage. The heterocaryon between slow growing strains produced protease early as well as late, and the activity increased far beyond the productions limit of each component strain. Upon measuring the nuclear ratios during cultivation, the effect was considered to be due to heterocaryotic vigor or a kind of heterosis. The heterozygous diploid between slow growers also yielded protease as well as the heterocaryon. When fast grower and slow grower were paired, the resulting diploid showed the highest activity of the enzyme among these strains.With 4 Figures in the Text 相似文献
994.
The mammalian target of rapamycin (mTOR) partner,raptor, binds the mTOR substrates p70 S6 kinase and 4E-BP1 through their TOR signaling (TOS) motif 总被引:12,自引:0,他引:12
Nojima H Tokunaga C Eguchi S Oshiro N Hidayat S Yoshino K Hara K Tanaka N Avruch J Yonezawa K 《The Journal of biological chemistry》2003,278(18):15461-15464
The mammalian target of rapamycin (mTOR) controls multiple cellular functions in response to amino acids and growth factors, in part by regulating the phosphorylation of p70 S6 kinase (p70S6k) and eukaryotic initiation factor 4E-binding protein 1 (4E-BP1). Raptor (regulatory associated protein of mTOR) is a recently identified mTOR binding partner that also binds p70S6k and 4E-BP1 and is essential for TOR signaling in vivo. Herein we demonstrate that raptor binds to p70S6k and 4E-BP1 through their respective TOS (conserved TOR signaling) motifs to be required for amino acid- and mTOR-dependent regulation of these mTOR substrates in vivo. A point mutation of the TOS motif also eliminates all in vitro mTOR-catalyzed 4E-BP1 phosphorylation and abolishes the raptor-dependent component of mTOR-catalyzed p70S6k phosphorylation in vitro. Raptor appears to serve as an mTOR scaffold protein, the binding of which to the TOS motif of mTOR substrates is necessary for effective mTOR-catalyzed phosphorylation in vivo and perhaps for conferring their sensitivity to rapamycin and amino acid sufficiency. 相似文献
995.
Transverse cortical microtubule (CMT) arrays in lettuce root epidermal cells randomize soon after a shift from pH 6.0 to pH 4.0, and this randomization is essential for root hair initiation. We investigated the hormonal regulation of CMT randomization. At pH 4.0, 1 micro M of the auxin competitive inhibitor 2-(p-chlorophenoxy)-2-methylpropionic acid (PCIB), 0.1 micro M of the ethylene biosynthesis inhibitor aminoethoxyvinylglycine (AVG) or 0.1 micro M of the ethylene action inhibitor Ag(+) suppressed CMT randomization and root hair initiation. At pH 6.0, addition of 0.1 micro M indole-3-acetic acid (IAA) or 1 micro M of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) induced CMT randomization and root hair initiation. Culturing with 0.1 micro M IAA plus 0.1 micro M AVG, or 1 micro M ACC plus 1 micro M PCIB also induced these phenomena. ACC (1 micro M) plus 100 micro M PCIB inhibited CMT randomization and root hair initiation, but 1 micro M AVG with 0.1 micro M Ag(+) and 0.1 micro M IAA induced them. These results suggest that auxin is essential for CMT randomization. As a higher concentration of PCIB was required to suppress CMT randomization when ACC was added, the greater amount of ethylene produced at pH 4.0 may promote the induction by auxin of CMT randomization in hair-forming cells. 相似文献
996.
Experiments were conducted using female golden hamsters to identify the presence of nerve growth factor (NGF) and its receptors NTRK1 and TNFRSF1B in the uteri of female animals and regulation on their expression by estrogen and progesterone. NGF and its receptor NTRK1 were immunolocalized to luminal epithelial cells, glandular cells, and stromal cells. TNFRSF1B was immunolocalized in luminal epithelial and glandular cells, with no staining found in stromal cells of the uterine horns of normal cyclic golden hamsters. Strong immunostaining of NGF and its receptors NTRK1 and TNFRSF1B was observed in uteri on the day of proestrus as compared to the other stages of the estrous cycle. Results of immunoblot analysis of NGF revealed that there was a positive correlation between uterine NGF expression and plasma concentrations of estradiol-17beta. To clarify the effects of estrogen and progesterone on NGF, NTRK1, and TNFRSF1B expression, adult female golden hamsters were ovariectomized and treated with estradiol-17beta and/or progesterone. Immunoblot analysis and immunohistochemistry indicated that estradiol-17beta stimulated expression of NGF and its two receptors in the uterus. Treatment with progesterone also increased NGF and NTRK1 expression in the uterus. However, no additive effect of these steroids on expression of NGF and its receptors was observed. Changes in uterine weights induced by estradiol-17beta and/or progesterone showed the same profile with that of NGF, suggesting that a proliferative act of NGF may be involved in uterine growth. These results suggest that NGF may play important roles in action of steroids on uterine function. 相似文献
997.
Kanho H Yaoya S Itani T Nakane T Kawahara N Takase Y Masuda K Kuroyanagi M 《Bioscience, biotechnology, and biochemistry》2004,68(10):2032-2039
Hairy roots of medicinal morning glory (Pharbitis nil) showed potent glucosylation activity against umbelliferone and aesculetin, so the glucosylation activity against several phenolic compounds was tested. Some coumarin derivatives and flavone derivatives having phenolic hydroxyl groups were incubated with the hairy roots. The coumarin derivatives and flavone derivatives almost disappeared from the culture medium in half a day. In the case of the coumarin derivatives, a 7-hydroxyl group was easily glucosylated. A methyl group at C-8 somewhat decreased the glucosylation to a hydroxyl group at C-7 of the coumarin skeleton. The 4-hydroxy coumarin derivatives were changed to acetophenone-type glucosides by incubation with the hairy roots through decarboxylation. Several flavonol derivatives were tested for glucosylation by the hairy roots. 3-Hydroxy flavone, 3.6-dihydroxyflavone and 3,7-dihydroxyflavone were glucosylated to give 3-glucosylated derivatives. Of these, 3,6-dihydroxyflavone was highly glucosylated, but not 3-hydroxyflavone or 3,7-dihydroxyflavone to the same degree. In the case of the flavones, a 3-hydroxy group could be predominantly glucosylated, and hydroxyl groups on the A and B ring of the flavones affected glucosylation by the hairy roots. 相似文献
998.
Kazuyoshi Sato Koichi Ishida Osamu Mutsushika Shoichi Shimizu 《Bioscience, biotechnology, and biochemistry》2013,77(12):3451-3421
´-Aminolevulinic acid (´-ALA) synthases from Protaminobacter ruber and Rhodopseudomonas spheroides were highly purified and characterized. The molecular weights of the ´-ALA synthases from P. ruber and R. spheroides were estimated to be 97,000 and 87,000, respectively. The optimum pH was about 8.0 for both enzymes. The P. ruber-enzyme showed Kms of 1.05 mM for glycine and 0.77 μM for pyridoxal-5’-phosphate (PLP), while the R. spheroides-enzyme showed Kms of 8.33 mM for glycine and 15 ´M for PLP. The P. ruber-enzyme was less stable during storage at 4°C or 37°C than the R. spheroides-enzyme. As to the effects of end-products, the P. ruber-enzyme was not inhibited by hemin, while the R.spheroides-enzyme was considerably inhibited by hemin. A higher concentration of vitamin B12 stimulated the reaction of the ´-ALA synthases, especially the P. ruber-enzyme. 相似文献
999.
Hideki Yamaguchi Nachi Yoshida Miho Takanashi Yuumi Ito Kiyoko Fukami Kazuyoshi Yanagihara Masakazu Yashiro Ryuichi Sakai 《PloS one》2014,9(1)
Scirrhous gastric carcinoma (SGC) has the worst prognosis of all gastric cancers, owing to its rapid expansion by invasion and frequent peritoneal dissemination. Due to the increased proliferation of stromal fibroblasts (SFs) that occurs within SGC lesions and the peritoneal metastatic sites, SFs have been proposed to support the progression of this disease. However, the biological and molecular basis and the pathological role of the intercellular interaction between SGC cells and SFs remain largely unknown. In this study, we investigated the role of SFs in the invasion of the extracellular matrix (ECM) by SGC cells. When SGC cells were cocultured with SFs derived from SGC tissue on three-dimensional (3D) Matrigel, they were attracted together to form large cellular aggregates that invaded within the Matrigel. Time-lapse imaging revealed that this process was associated with extensive contraction and remodeling of the ECM. Immunofluorescence and biochemical analysis showed that SGC cells stimulate phosphorylation of myosin light chain and actomyosin-mediated mechanical remodeling of the ECM by SFs. By utilizing this assay system for inhibitor library screening, we have identified several inhibitors that potently suppress the cooperation between SGC cells and SFs to form the invasive structures. Among them, a Src inhibitor dasatinib impaired the interaction between SGC cells and SFs both in vitro and in vivo and effectively blocked peritoneal dissemination of SGC cells. These results indicate that SFs mediate mechanical remodeling of the ECM by SGC cells, thereby promoting invasion and peritoneal dissemination of SGC. 相似文献
1000.
Chiho Taniguchi Takehiro Sugawara Sakura Onoue Kazuyoshi Kawahara 《Microbiology and immunology》2019,63(8):334-337
Lipid A in lipopolysaccharide (LPS) of Escherichia coli mutant strains was modified by the introduction of myristoyltransferase gene cloned from Klebsiella pneumoniae. When the gene was introduced into the mutant having lipid A containing only 3‐hydroxymyristic acids, it produced lipid A with two additional myristic acids (C14:0). When the same gene was introduced into the mutant with pentaacylated lipid A containing one lauric acid (C12:0), C12:0 was replaced by C14:0. IL‐6‐inducing activity of LPS with modified lipid A structure suggested that C12:0 in lipid A could be replaced by C14:0 without changing the immunostimulating activity. 相似文献