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1.
Both Km and Vmax values of cytochrome c oxidase for cytochrome c were elevated in oleic acid-incorporated mitochondria, whereas the amount of oleic acid incorporated into submitochondrial particles was smaller than that into mitochondria and the fatty acid had little effect on the enzyme activity. The degree of change in the bulk membrane fluidity was, however, almost the same in mitochondria and submitochondrial particles. Solubilized cytochrome c oxidase was insensitive to the effect of oleic acid. Oleic acid may act as a modifier of the interaction between cytochrome c oxidase and membrane lipids. 相似文献
2.
From siliceous shales (Lower Carboniferous, Rheinisches Schiefergebirge), in direct neighborhood to a bed of allodapic limestone, the following fluontized radiolarian fauna has been extracted by chemical transformation of originally calcified skeletons:Albaillella cartalla, Latentifistula turgida, Eostylodktya cf. eccentrica, Tetragregnon sycamorensis sycamorensis, Belowea variabilis, Callela? hexactinia, Entactinia tortispina and Entactinia variospina. The limestone bed has been dated by calcareous foraminifera as being mid Visean in age (V 2b-3a, Cf 5-foraminiferal zone). The diagenetic calcification took place after the selective dissolution of the skeletons and was in itself not selective. 相似文献
3.
Zoospores of the marine chytrid Rhizophydium littoreum are attracted to a variety of substances common to their environment. In general, carbohydrates and polysaccharides elicited strong concentration-dependent positive responses. There was no direct correlation between all substances used as foods and those stimulating positive responses. The chemotactic activities of this organism should, however, tend to bring it toward concentrated food sources. 相似文献
4.
Enhanced secretion of Escherichia coli beta-lactamase by a spontaneous erythromycin-resistant mutant of Bacillus subtilis 总被引:1,自引:0,他引:1
An extracellular-protease-deficient mutant, ME142, was isolated from Bacillus subtilis as a spontaneous erythromycin-resistant (Eryr) clone. This mutant showed conditional sporulation and only sporulated normally in the absence of erythromycin. In the presence of the antibiotic, sporulation was greatly reduced. Production of extracellular proteases by ME142 also exhibited conditional deficiency, possibly due to pleiotropic effects of the sporulation deficiency. The production of protease was 2-10% that of the wild-type level in the presence of erythromycin. ME142 showed poor competence for transformation even in the absence of erythromycin; however, derivatives of ME142 were isolated which had the same Eryr phenotype but which exhibited normal competence. One such mutant, ME162, was used as a host for the secretion of Escherichia coli beta-lactamase. The amount of beta-lactamase in the culture supernatants of ME162 increased significantly when the cells were cultured with erythromycin, suggesting that proteolysis of the beta-lactamase in the supernatants of ME162 was greatly reduced as compared to that in the supernatants of the wild-type strain. 相似文献
5.
Isolation of Com1, a New Gene Required to Complete Meiotic Double-Strand Break-Induced Recombination in Saccharomyces Cerevisiae 总被引:1,自引:1,他引:0 下载免费PDF全文
We have designed a screen to isolate mutants defective during a specific part of meiotic prophase I of the yeast Saccharomyces cerevisiae. Genes required for the repair of meiotic double-strand breaks or for the separation of recombined chromosomes are targets of this mutant hunt. The specificity is achieved by selecting for mutants that produce viable spores when recombination and reductional segregation are prevented by mutations in SPO11 and SPO13 genes, but fail to yield viable spores during a normal Rec(+) meiosis. We have identified and characterized a mutation com1-1, which blocks processing of meiotic double-strand breaks and which interferes with synaptonemal complex formation, homologous pairing and, as a consequence, spore viability after induction of meiotic recombination. The COM1/SAE2 gene was cloned by complementation, and the deletion mutant has a phenotype similar to com1-1. com1/sae2 mutants closely resemble the phenotype of rad50S, as assayed by phase-contrast microscopy for spore formation, physical and genetic analysis of recombination, fluorescence in situ hybridization to quantify homologous pairing and immunofluorescence and electron microscopy to determine the capability to synapse axial elements. 相似文献
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Ender A. Finol Cristina H. Amon 《Computer methods in biomechanics and biomedical engineering》2013,16(4):319-328
In continuing the investigation of AAA hemodynamics, unsteady flow-induced stresses are presented for pulsatile blood flow through the double-aneurysm model described in Part I. Physiologically realistic aortic blood flow is simulated under pulsatile conditions for the range of time-average Reynolds numbers 50 h Re m h 300. Hemodynamic disturbance is evaluated for a modified set of indicator functions which include wall pressure ( p w ), wall shear stress ( w ), Wall Shear Stress Gradient (WSSG), time-average wall shear stress ( w *), and time-average Wall Shear Stress Gradient WSSG *. At peak flow, the highest shear stress and WSSG levels are obtained at the distal end of both aneurysms, in a pattern similar to that of steady flow. The maximum values of wall shear stresses and wall shear stress gradients are evaluated as a function of the time-average Reynolds number resulting in a fourth order polynomial correlation. A comparison between numerical predictions for steady and pulsatile flow is presented, illustrating the importance of considering time-dependent flow for the evaluation of hemodynamic indicators. 相似文献
8.
Spines are the major element of radiolarian skeletons; they are usually solid or, rarely, hollow. Subcylindrical hollow spines and other hollow structures of radiolarian skeletons appeared in the Middle Cambrian. Later, hollow skeletal structures repeatedly developed in the evolution of all radiolarian classes of the subphylum Polycystina throughout the Phanerozoic to the Recent. The analysis of appearance and distribuion in the Phanerozoic of morphotypes with hollow spines has shown that the formation of hollow skeletal structures allowed better adaptation for the planktonic mode of life and could become a key adaptation in struggle for life under stressful conditions. 相似文献
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Ryuji Asano Amon Nagami Yuki Fukumoto Futoshi Yazama Hideyuki Ito Isao Sakata Akihiro Tai 《Bioorganic & medicinal chemistry》2013,21(8):2298-2304
Three new water-soluble chlorin derivatives 3, 5 and 8 for potential use as photosensitizers in photodynamic therapy (PDT) for cancer were synthesized from photoprotoporphyrin IX dimethyl ester (1). The in vivo biodistribution and clearance of chlorin derivatives 3, 5 and 8 were investigated in tumor-bearing mice. Iminodiacetic acid derivative 8 showed the greatest tumor-selective accumulation among the new chlorin derivatives with maximum accumulation in tumor tissue at 3 h after intravenous injection and rapid clearance from normal tissues within 24 h after injection. The in vivo therapeutic efficacy of PDT using 8 was evaluated by measuring tumor growth rates in tumor-bearing mice with 660 nm light-emitting diode irradiation at 3 h after injection of 8. Tumor growth was significantly inhibited by PDT using 8. These results indicate that iminodiacetic acid derivative 8 is useful as a new photosensitizer to overcome the disadvantages of photosensitizers that are currently in clinical use. 相似文献