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61.
Kunie Yoshikawa Takehiko Nohmi Rumiko Miyata Motoi Ishidate Jr. Naoki Ozawa Masakazu Isobe Tadashi Watabe Tuneo Kada Takashi Kawachi 《Mutation research》1982,96(2-3)
Comparison studies for detecting differences between liver microsome and S9 preparations from 4 strains (Donryu, Fischer, Sprague-Dawley, Wistar) of young male rats were carried out with pretreatment of the animals by inducers such as PCBs and PB plus 5,6-BF. Each microsome fraction was assayed for the enzymic activity of metabolism of model substrates such as aniline, benzophetamine, BP, DMN and 7-ethoxycoumarin. The hepatic S9 sample was also compared, as regards its metabolizing ability to activate 9 pre-mutagens (2AA, AAF, o-AAT, BP, DAB, DMBA, DMN, m-PDA, quinoline) to directly acting mutagens in the Salmonella/hepatic S9 activation test by using TA98, TA100 and TA1537 strains with or without cytochrome P450 inhibitors (SKF-525A, metyrapone, 7,8-benzoflavone).In the enzymic assay with PCBs-induced microsomes, BP hydroxylation revealed a strain-specific difference: the microsomes from Fischer and Wistar rats were more effective for metabolizing BP than those from the other strains of rat. The effect of induction by PB plus 5,6-BF for Fischer rats showed relatively higher enzymic activity in the same induction group. Other microsomes prepared from rats with and without induction by PB plus 5,6-BF did not show a clear-cut strain dependency in the enzymic activities assayed.In the mutation experiments with hepatic S9 samples, the examination of DAB and quinoline revealed a marked strain difference when S9 samples prepared from PCBs-pretreated and PB-plus-5,6-BF-induced rats were used: the S9 sample from Fischer rats was available for activating the two pre-mutagens to directly acting mutagens. No marked difference in the metabolic activation of the remaining 7-pre-mutagens was observed on other S9 preparations.In examinations of mutagenicity activities with the use of three inhibitors, the two S9 preparations made with the two induction methods showed inhibition profiles closely similar to each other. However, there were minor differences in the profiles by these inhibitors.From these findings it was concluded that Fischer rat-liver S9 is useful for detecting mutagens in the metabolic activation test, when induction by PB plus 5,6-BF was used in the Ames Salmonella test. 相似文献
62.
Dissociability of the monomer ribosomes prepared from dry and imbibed pine (Pinus thunbergii) seed embryos was analyzed in sucrose density gradient containing a high salt buffer. Abnormal dissociation into the subunits
was observed with the ribosome preparation from dry seed embryos when compared with that from imbibed seed embryos, i.e. each
subunit peak was broader and localized at a lower site in sucrose density gradient. This indicates some change(s) in ribosomes
during imbibition of seeds. These ribosomal changes also progressedin vitro. That is, after incubation of ribosome preparation from dry seed embryos in a high salt buffer for 5 min at 30 C or in a
low salt buffer for 15 hr at 0 C, complete dissociation into the normal subunits was observed. No difference was found between
polyacrylamide gel electrophoresis patterns of ribosomal RNA from dry and imbibed seed embryos. These results suggest some
alteration in the protein components of ribosome during imbibition of pine seeds.
This paper is dedicated to Prof. Shyogo Sawamura, Utsunomiya University on his retirement in March, 1979. 相似文献
63.
K. Goshima 《Experimental cell research》1975,92(2)
- 1. 1. Single myocardial cells from fetal mouse heart beat spontaneously in monolayer culture. In standard medium they maintained a constant beating rate for at least 5 h. After the beating rate of individual cells had been accelerated for a short time by electrical stimulation, the original beating rate could be immediately restored by interrupting the stimulation. Quiescent myocardial cells from neonatal mouse atrium could be induced to beat by electrical stimulation and most of them ceased to beat again immediately by interrupting the stimulation.
- 2. 2. After the spontaneous beating of individual myocardial cells had been stopped or slowed down for a short time by incubation in medium of low temperature or high potassium or low calcium concentration, the original beating rate could be restored by replacing the cells in the original, normal medium.
- 3. 3. After the spontaneous beating of individual myocardial cells had been stopped by adding a metabolic inhibitor, such as 2,4-dinitrophenol or 2-deoxyglucose, the original beating rate could be restored by replacing the cells in the original, normal medium.
- 4. 4. Both single myocardial cells and cell clusters showed arrhythmia, including flutter and fibrillation, in medium of low potassium or high calcium concentration. After a short period of arrhythmia, the original beating rate could be restored by replacing the cells in the original, normal medium. The arrhythmia of cell clusters produced in either low potassium or high calcium medium was also corrected immediately by addition of quinidine sulfate.
64.
The mechanism by which dihydroconiferyl alcohol (DCA) stimulatesindole-3-acetic acid (IAA)-induced elongation of cucumber hypocotylsections was studied. Although DCA did not affect the uptakeof IAA-5-3H by hypocotyl sections, the endogenous level of IAA-5-3Hin DCA-treated sections was much higher than in DCA untreatedones. IAA-5-3H in the incubation medium was degraded in thepresence of hypocotyl sections, and this degradation of IAAwas inhibited by DCA. An in vitro experiment with horseradishperoxidase revealed that DCA inhibited the IAA degrading activityof the oxidase, as did caffeic acid and ferulic acid. Theseresults suggested that DCA enhances IAA-induced cucumber hypocotylelongation by acting as an antioxidant of IAA. (Received June 4, 1975; ) 相似文献
65.
66.
A versatile, two-step chromatographic method using DEAE-Toyopearl(Toyo Soda, Japan) is described for purifying photosystem IIreaction center complex from digitonin extracts of spinach thylakoidmembranes. The method is very simple and brings about an approximatefour-fold increase in the specific activity, on a chlorophyllbasis, of 2,4-dichlorophenol-indophenol photoreduction with1,5-diphenylcarbazide (to about 2,000 µ electron equivalentsper mg chlorophyll per h), with an approximate 40 percent recoveryin chlorophyll. The SDS-polyacrylamide gel electrophoresis performedin the presence of 4 M urea in the analyzing gel shows fourpolypeptide bands of the photosystem II reaction center of about47, 43, 30 and 9 kilodaltons. The absorption and fluorescence properties, as well as the pigmentand chemical compositions and the above mentioned polypeptideprofile of the purified complex are essentially identical withthose of the preparations isolated by the previously describedmethod (Satoh 1982). The digitonin solubilization of thylakoid membranes destroysthe water splitting machinery, so that the purified complexshows no oxygen evolving activity, even although 0.60.7atoms of manganese per 50 chlorophyll molecules still remain. (Received March 19, 1985; Accepted July 19, 1985) 相似文献
67.
68.
Satsuki Tsuji Naoki Shibata Hayato Sawada Masayuki Ushio 《Molecular ecology resources》2020,20(5):1323-1332
Recent advances in environmental DNA (eDNA) analysis using high‐throughput sequencing (HTS) enable evaluation of intraspecific genetic diversity in a population. As the intraspecific genetic diversity provides invaluable information for wildlife conservation and management, there is an increasing demand to apply eDNA analysis to population genetics and the phylogeography by quantitative evaluation of intraspecific diversity. However, quantitative evaluations of intraspecific genetic diversity using eDNA is not straightforward because the number of eDNA sequence reads obtained by HTS may not be an index of the quantity of eDNA. In this study, to quantitatively evaluate genetic diversity using eDNA analysis, we applied a quantitative eDNA metabarcoding method using the internal standard DNAs. We targeted Ayu (Plecoglossus altivelis altivelis) and added internal standard DNAs with known copy numbers to each eDNA sample obtained from three rivers during the library preparation process. The sequence reads of each Ayu haplotype were successfully converted to DNA copy numbers based on the relationship between the copy numbers and sequence reads of the internal standard DNAs. In all rivers, the calculated copy number of each haplotype showed a significant positive correlation with the haplotype frequency estimated by a capture‐based survey. Furthermore, estimates of genetic indicators such as nucleotide diversity based on the eDNA copy numbers were comparable with those estimated based on a capture‐based study. Our results demonstrate that eDNA analysis with internal standard DNAs enables reasonable quantification of intraspecific genetic diversity, and this method could thus be a promising tool in the field of population genetics and phylogeography. 相似文献
69.
70.
Molecular and Cellular Biochemistry - The aims of this study were to investigate the impact of caloric restriction (CR) on cardiac senescence in an animal model of diabetes and examine the signal... 相似文献