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1.
2.
Hidenori Shinkawa Masanori Sugiyama Yuji Hatada Takeshi Ohuchi Masao Udagawa Osamu Nimi 《Biotechnology letters》1991,13(8):537-542
Summary The bald mutants from streptomycin (SM)-producingStreptomyces griseus 2247 obtained by incubation at high temperature (36° C), designated as HT strains, lost resistance to their own antibiotic and scarcely produced the antibiotic. Although SM susceptibility in the mutant was due to loss of SM 6-phosphotransferase activity produced in the cell, the gene coding for the enzyme cloned from an HT strain was surely expressed inS. lividans 1326 as a host. Northern blot analysis showed that the corresponding RNA is not detected in the mutant, indicating that though the gene encoding SM 6-phosphotransferase, at least, the structural gene is not deleted in the cell, the expression is silent. 相似文献
3.
The maximal micellar solubility, distribution and apparent monomer activity of cholesterol in taurine-conjugated cholate and chenodeoxycholate micellar solutions were studied to clarify the different modulating effect of these bile salt species on cholesterol uptake in an intestinal lumen. The maximal micellar solubility was significantly greater in taurochenodeoxycholate. The intermicellar cholesterol monomer concentration was not significantly different between the two kinds of micellar solution. However, the apparent cholesterol monomer activity determined using an artificial organic phase (polyethylene disc) was significantly higher in taurocholate than that in taurochenodeoxycholate. A linear relationship between the intermicellar cholesterol concentration and the apparent cholesterol monomer activity was found, with the slope depending upon the bile salt species. It is concluded that the difference in partitioning of cholesterol from taurocholate and taurochenodeoxycholate micelles into a fixed organic phase may contribute in part to the different regulating effects of these bile salts on the uptake of cholesterol in the intraluminal phase. 相似文献
4.
Cerebral Blood Flow and Oxidative Metabolism in Conscious Fischer-344 Rats of Different Ages 总被引:1,自引:1,他引:0
Hidenori Takei Wendy R. Fredericks Edythe D. London Stanley I. Rapoport 《Journal of neurochemistry》1983,40(3):801-805
Abstract: The cerebral metabolic rates for O2 and for glucose were measured in conscious, fasted male Fischer-344 rats at the ages of 3, 12, and 24 months, and cerebral blood flow was determined with 14 C-iodoantipyrine. The metabolic rates for oxygen and glucose were obtained by multiplying blood flow by the O2 and glucose concentration differences, respectively, between blood in the femoral artery and in the superior sagittal sinus. Mean cerebral blood flow and the metabolic rates for oxygen and glucose did not differ significantly (p > 0.05) between 3 and 12 or between 12 and 24 months. Nor did the arteriovenous differences for O2 and for glucose change significantly with age. Because the superior sagittal sinus drains blood mainly from the cerebral cortex, the results indicate that average cerebral cortical oxidative metabolism, and the coupling ratios between the cerebral metabolic rate for oxygen and cerebral blood flow and between the cerebral metabolic rate for glucose and cerebral blood flow, do not change significantly with age in the Fischer-344 rat. 相似文献
5.
Diurnal K+ and Anion Transport in Phaseolus Pulvinus 总被引:1,自引:0,他引:1
Diurnal movement of Phaseolus leaf is caused by deformationof the laminar pulvinus located at the joint of the leaf bladeand the petiole. The plants were cultured in solutions withvarious ion compositions, and changes of K+, Na+, Ca2+, Mg2+,Cl, NO3 and P1 concentrations both in the upperand lower parts of the laminar pulvinus were measured. Culturein 10 mM KCl solution caused an increase in K+ and Clconcentrations both in the upper and lower parts without anysignificant change in the concentration of NO3; culturein 10 mM KNO3 solution caused an increase in K+ and NO3concentration without any significant change in the concentrationof Cl; and culture in 10 mM KH2PO4 solution caused anincrease in K+ and P1 concentrations without any significantchange in the concentrations of NO3- and Cl. K+ moved from the upper to lower parts or from the lower toupper parts diurnally in all plants cultured in any solutionmentioned above. The main inorganic anion that accompanied thisK+ movement was Cl in KCl solution, and NO3 inKNO3 solution. When the seedlings were cultured in distilledwater or in KH2PO4 solution, neither Cl NO3 norP1 accompanied this K+ movement. In these cases, mainly H+ and/ororganic anions are supposed to move in exchange for and/or incombination with K+ movement. (Received November 8, 1982; Accepted June 13, 1983) 相似文献
6.
Hidenori Tachida 《Journal of genetics》1996,75(1):33-48
Models of the theory of nearly neutral mutation incorporate a continuous distribution of mutation effects in contrast to the theory of purely neutral mutation which allows no mutations with intermediate effects. Previous studies of one such model, namely the house-of-cards mutation model, assumed normal distribution of mutation effect. Here I study the house-of-cards mutation model in random-mating finite populations using the weak-mutation approximation, paying attention to the effects of the distribution of mutant effects. The average selection coefficient, substitution rate and average heterozygosity in the equilibrium and transient states were studied mainly by computer simulation. The main findings are: (i) Very rapid decrease of the substitution rate and very slow approach to equilibrium as selection becomes stronger are characteristics of assuming normal distribution of mutant effect. If the right tail of the mutation distribution decays more rapidly than that of the normal distribution, the decrease of substitution rate becomes slower and equilibrium is achieved more quickly. (ii) The dispersion index becomes smaller or larger than 1 depending on the time and the intensity of selection, (iii) LetN be the population size. When selection is strong the ratio of 4N times the substitution rate to the average heterozygosity, which is expected to be 1 under neutrality, is larger than 1 in earlier generations but becomes less than 1 in later generations. These findings show the importance of the distribution of mutant effect and time in determination of the behaviour of various statistics frequently used in the study of molecular evolution. 相似文献
7.
Hidenori Sassa Takeshi Nishio Yasuo Kowyama Hisashi Hirano Takato Koba Hiroshi Ikehashi 《Molecular & general genetics : MGG》1996,250(5):547-557
Stylar riboncleases (RNases) are associated with gametophytic self-incompatibility in two plant families, the Solanaceae and the Rosaceae. The self-incompatibility-associated RNases (S-RNases) of both the Solanaceae and the Rosaceae were recently reported to belong to the T2 RNase gene family, based on the presence of two well-conserved sequence motifs. Here, the cloning and characterization of S-RNase genes from two species of Rosaceae, apple (Malus × domestica) and Japanese pear (Pyrus serotina) is described and these sequences are compared with those of other T2-type RNases. The S-RNases of apple specifically accumulated in styles following maturation of the flower bud. Two cDNA clones for S-RNases from apple, and PCR clones encoding a further two apple S-RNases as well as two Japanese pear S-RNases were isolated and sequenced. The deduced amino acid sequences of the rosaceous S-RNases contained two conserved regions characteristic of the T2/S-type RNases. The sequences showed a high degree of diversity, with similarities ranging from 60.4% to 69.2%. Interestingly, some interspecific sequence similarities were higher than those within a species, possibly indicating that diversification of S-RNase alleles predated speciation in the Rosaceae. A phylogenetic tree of members of the T2/S-RNase superfamily in plants was obtained. The rosaceous S-RNases formed a new lineage in the tree that was distinct from those of the solanaceous S-RNases and the S-like RNases. The findings suggested that self-incompatibility mechanisms in Rosaceae and Solanaceae are similar but arose independently in the course of evolution. 相似文献
8.
Keitaro Kiyosawa 《Physiologia plantarum》1996,97(1):180-184
Movements of ions are considered to be governed by the electroneutrality rule. Therefore, a cation moving across the cell membrane into the cell either passively or actively should move together with its counterion, an anion, in equal amounts of charge or in exchange for another cation inside the cell. This means that the net influx of the cation in question should be affected by the permeability of its counterion and/or another cation inside the cell. To examine osmotic and ionic regulation in Chara cells, cell fragments of Chara having a lower osmotic pressure than normal (L-cell fragments) were prepared. The L-cell fragments were individually put into various dilute electrolyte solutions and their osmotic potentials were measured with a turgor balance. Concentrations of K+, Na+, Ca2+, Mg2+, Cl?, NO?3. and SO2?4. in the external electrolyte solutions in which L-cells had been incubated were also analysed by ion chromatography. The results showed that in 0.5 mM KCL + 0.1 mM CaCl2 solution, Chara L-cell fragments absorbed K+ and Cl? to maintain electroneutrality and then regained their osmotic potential very rapidly. When the anion was Cl, the cation absorbed at the highest rate was K+ On the other hand, when the cation was K, the anion absorbed at the highest rate was Cl, Other ions Ca2+, SO2?4 and NO?3 showed much less permeability than K+ and Cl ?for the Chara plasma membrane. The conclusion from these findings was that due to the constraint of electroneutral transport, the uptake rate of a salt into L-cells is limited by the permeability of the least permeable ion. 相似文献
9.
Naoko Miyano-Kurosaki Hideki Nakashima Koji Ichiyama Kazuhiko Inazawa Hidenori Tabata Hideyuki Tanabe Kiyotaka Ohnishi Hiroshi Mizusawa Yukako Ohshiro Naoki Yamamoto 《Microbiology and immunology》1994,38(10):813-818
A subclonal cl.1–14 cell was established from a monocytic cell line U937 by a limiting dilution method. The anti-HIV-1 activity of some antiviral compounds was evaluated in HIV-1-infected cl.1–14 cells. The results demonstrated that although AZT was a potent inhibitor of HIV-1 replication in cl.1–14 cells, its 50% effective concentration (EC50) values was 80 times higher than that in HIV-1 infected MT-4 cells; the EC50 of AZT was 0.16 μM and 0.002 μM in cl.1–14 and MT-4 cells, respectively. In contrast, the anti-HIV-1 activity of ddA, ddI and ddC in cl.1–14 cells was comparable to that in MT-4 cells. The antiviral activity of nevirapine, dextran sulfate, curdlan sulfate and T22 did not differ significantly between the cl. 1–14 and MT-4 cells. The antiviral activity of several compounds in the HIV-1-infected cl.1–14 cells was similar to that in the HIV-1jr -fl -infected human peripheral macrophages. Our results suggest that cl.1–14 cell cultures are very useful for estimating antiviral activity and more advantageous than the use of peripheral blood macrophages. 相似文献
10.
Nakazawa Miki; Hayashi Hidenori; Yoshida Yuhji; Manabe Katsushi 《Plant & cell physiology》1993,34(1):83-91
Peptide fragments were obtained by limited proteolysis withtrypsin and Staphylococcus aureus V 8 protease from either thePR or the PFR form of 121-kDa phytochrome purified from etiolatedpea (Pisum sativum L.) shoots. Patterns of bands after polyacrylamidegel electrophoresis in the presence of SDS of the digests weredifferent, with some bands appearing preferentially when thedigestions were carried out with the PR or the PFR form. Amino-terminalsequences of the fragments were analyzed to determine the exactlocations of the amino-termini of the fragments within the aminoacid sequence of the apoprotein of pea phytochrome. The aminoacid compositions of some of the sequenced fragments were determinedin order to confirm the carboxy-terminal amino acids. Threecleavage regions were identified as kinetically favored sitesof cleavage of PFR (Arg-746 to Lys-752, around Glu-877 and aroundArg-1010), whereas only one was identified for PR (Glu-38 toArg-62). Regions of Glu-255, Arg-383, Arg-583 to Glu-620 andLys-1093 to Glu-1115 were also identified as potential sitesof proteolytic cleavage in both forms of the phytochrome. Othercleavage sites, the specificities of which have not yet beendetermined, are Glu-404, Glu-695 and Lys-1045. Surface-exposed parts of phytochrome in the PR and PFR formsare discussed. (Received June 13, 1992; Accepted October 27, 1992) 相似文献