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861.
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863.
Titration of State 4 rat-liver mitochondria at pH 7.2 with the uncoupler 3,5-di-tert-butyl-4-hydroxybenzylidenemalononitrile (SF 6847) at various concentrations of mitochondria and using various substrates indicates that under optimal conditions less than 0.2 molecule of 3,5-di-tert-butyl-4-hydroxybenzylidenemalononitrile per respiratory chain is sufficient to induce complete uncoupling. This result suggests that there is not a stoichiometric relationship between uncoupler molecules and cytochrome c oxidase, involved in oxidative phosphorylation, or between the former and phosphorylation assemblies. Experiments on the release by 3,5-di-tert-butyl-4-hydroxybenzylidenemalononitrile of azide-inhibited respiration of State 3 mitochondria and titrations with 5-chloro-3-tert-butyl-2'-chloro-4'-nitrosalicylanilide (S13) of State 4 mitochondria at various mitochondrial concentrations confirm this conclusion. 相似文献
864.
Pregnant A/J female mice, which had drunk tap water or a 0.05% caffeine solution for 8-19 weeks after weaning, were each injected sc with 150 or 250 mg/kg caffeine once on day 13 of gestation. After 150 mg/kg caffeine the frequencies at term of fetal death, external malformation, and subcutaneous hematomas were significantly lower in the caffeine- than water-drinking group. After 250 mg/kg caffeine the frequency of fetal death but not of malformations and hematomas was lower in the group with caffeine pretreatment. These findings were explained by assuming that long-term ingestion of caffeine induced and increased rate of degradation of caffeine administered during pregnancy. 相似文献
865.
866.
Naoko Arashida Takeshi Terada Takuya Okimi Yo Kikuchi Shuhei Hashiro 《Bioscience, biotechnology, and biochemistry》2018,82(10):1683-1693
Gram-negative bacterial quorum sensing is mainly regulated by an extracellularly produced N-acylhomoserine lactone (AHL). AHL consists of a lactone ring and an acyl chain, which generally varies from C4 to C18 in length and affords species-specific variety. In this study, we developed an ultra-high performance liquid chromatography tandem mass spectrometry system and detected two kinds of long chain AHLs with chain length C20 from the reverse-phase thin layer chromatography-fractionated cultured supernatant of the marine photosynthetic bacterium Rhodovulum sulfidophilum. By fragmentation search analysis to detect compounds with a homoserine lactone ring moiety for data dependent acquisition, a minor AHL, presumed to be 3-OH-C18-homoserine lactone (HSL), was also found. Among the detected C20-HSLs, 3-OH-C20-HSL was structurally identified and 3-OH-C20:1-HSL was strongly suggested. To our knowledge, this is the first report to show a novel AHL with the longest C20 acyl side chain found to date.
Abbreviations: AGC: automatic gain control; AHL: N-acylhomoserine lactone; CD: cyclodextrin; CID: collision induced dissociation; DDA: data dependent acquisition; EPI: enhanced product ion; FISh: fragment ion search; HCD: high energy collisional dissociation; HSL: homoserine lactone; IT: injection time; LC: liquid chromatography; MS: mass spectrometry; PRM: parallel reaction monitoring; RP: reverse phase; SRM: selected reaction monitoring; TLC: thin layer chromatography; UHPLC: ultra high performance liquid chromatography 相似文献
867.
868.
Nguyen Cong Thuan Keisuke Koba Midori Yano Akiko Makabe Co Thi Kinh Akihiko Terada Sakae Toyoda Naohiro Yoshida Yotaro Tanaka Masanori Katsuyama Muneoki Yoh 《Limnology》2018,19(1):115-126
Rivers are important sources of N2O emissions into the atmosphere. Nevertheless, N2O production processes in rivers are not well identified. We measured concentrations and isotopic ratios of N2O, NH4 +, NO2 ?, and NO3 ? in surface water to identify the microbial processes of N2O production along the Tama River in Japan. We also measured the functional gene abundance of nitrifiers and denitrifiers (amoA-bacteria, nirK, nirS, nosZ clade I, nosZ clade II) together with concentrations of dissolved organic carbon (DOC) and fluorescence intensities of protein and humic components of dissolved organic matter (DOM) to support the elucidation of N2O production processes. The observed nitrogen (δ15N) and oxygen (δ18O) of N2O were within the expected isotopic range of N2O produced by nitrate reduction, indicating that N2O was dominantly produced by denitrification. The positive significant correlation between N2ONet concentration and nirK gene abundance implied that nitrifiers and denitrifiers are contributors to N2O production. Fluorescence intensities of protein and humic components of DOM and concentrations of DOC did not show significant correlations with N2O concentrations, which suggests that DOC and abundance of DOM components do not control dissolved N2O. Measurement of isotope ratios of N2O and its substrates was found to be a useful tool to obtain evidence of denitrification as the main source of N2O production along the Tama River. 相似文献
869.
Summary Transport of benzenesulfonic acid derivatives through the rat erythrocyte membrane was studied. The transport properties, such as pH-dependence and effects of reagents reacting with amino-groups, were similar to those of anions like Cl– through the human erythrocyte membrane. The rate of transport of anions through rat erythrocyte membranes is higher than through those of other mammals, such as guinea pig and bovine erythrocyte membranes. This relatively high rate of transport makes the rat erythrocyte membrane suitable for use in comparative studies on the transports of slowly penetrating substances, such as organic anions. The transport velocities of benzenesulfonic acid derivatives were compared with their physico-chemical properties. It was shown that the hydrophobicity has no effect on the transport, but the electronic property has a significant effect: the transport rate is mainly dependent on thee
– donor capacities. This feature is the inverse to the well-known inhibitory effect of these derivatives on other anion transport: the inhibition is mainly dependent on thee
– acceptor capacities. It is suggested that the transport is regulated by the binding capacity of anions to the transport site. 相似文献
870.