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991.
992.
Oxidative stress contributes to cancer pathologies and to apoptosis. Marine algae exhibit cytotoxic, antiproliferative and apoptotic effects; their metabolites have been used to treat many types of cancer. We investigated in culture extracts of Petalonia fascia, Jania longifurca and Halimeda tuna to determine their effects on mouse neuroblastoma cell line, NA2B. NA2B cells were treated with algae extracts, and the survival and proliferation of NA2B cells were assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The effects of algae extracts on oxidative stress in NA2B cells also were investigated using nitric oxide synthase (NOS) immunocytochemistry and apoptosis was assessed using terminal deoxynucleotidyl transferase dUTP nick end labeling. We observed significant neurite inhibition with moderate damage by the neurotoxicity-screening test (NST) at IC50 dilutions of the extracts. MTT demonstrated that J. longifurca extracts were more toxic than P. fascia and H. tuna extracts. We found an increase of endothelial and inducible NOS immunostaining for oxidative stress and TUNEL analysis revealed increased apoptosis after application of extract. Our findings suggest that the algae we tested may have potential use for treatment of cancer. 相似文献
993.
Statistical tests for Hardy–Weinberg equilibrium are important elementary tools in genetic data analysis. X‐chromosomal variants have long been tested by applying autosomal test procedures to females only, and gender is usually not considered when testing autosomal variants for equilibrium. Recently, we proposed specific X‐chromosomal exact test procedures for bi‐allelic variants that include the hemizygous males, as well as autosomal tests that consider gender. In this study, we present the extension of the previous work for variants with multiple alleles. A full enumeration algorithm is used for the exact calculations of tri‐allelic variants. For variants with many alternate alleles, we use a permutation test. Some empirical examples with data from the 1,000 genomes project are discussed. 相似文献
994.
The time-course of micronucleated polychromatic erythrocytes (MPCE) in mouse bone marrow and peripheral blood, induced by an acute 0.1 Gy dose of X-rays, was determined using flow cytometric analysis, which made frequent sampling possible and allowed use of a dose low enough not to affect erythroid cell proliferation. The frequency of MPCE (fMPCE) began to increase in the bone marrow at 10 h after irradiation and reached a maximum at 28 h after irradiation. In the peripheral blood fMPCE began to increase at 20 h after irradiation and peaked at about 40 h after irradiation. The time-course found is discussed on the basis of data on the differentiation of erythroid cells. The results indicate that the micronuclei registered in polychromatic erythrocytes may originate from lesions induced not only during the last cell cycle but also during earlier ones. After an acute dose of 1.0 Gy of X-rays the maximum fMPCE was delayed both in bone marrow and peripheral blood reflecting an effect on the cell cycle progression of erythroblasts. 相似文献
995.
北美CHIHUAHUAN荒漠啮齿动物群落动态:Ⅲ.变量的频次分布和预测 总被引:2,自引:2,他引:0
本文用X^2方和柯尔莫哥洛夫检验分析了北美Chihuahuan荒漠啮齿动物群落6个生态学变量的频次分布,并用移动平均和指数平滑方法拟合了这些变理的动态变化。结果显示:1)结合种群密度、生物量、物种均匀性和生物量均匀性服从正态分布;2)物种数和物种多样性的频次为向右偏斜的分布,无法用常见的理论分布来近似表示;3)单移动平均和双移动平均分别较好地描述了和的种多样性和物种均匀性;4)其余4个变量可用单指 相似文献
996.
997.
K. Gasiorowski K. Szyba J. Urban M. Cieslak-Golonka S. M. Zakeeruddin M. Grätzel D. M. Fraser 《Biometals》1995,8(3):257-262
Five novel tris-(4,4-substituted-2,2-bipyridine) complexes of the group VIII metals [Fe(II), Ru(II) and Os(II)] (all having been previously examined electrochemically with respect to their ability to act as electron-transfer mediators for redox enzymes) were assayed in the Ames test to evaluate their mutagenic activity. For the bipyridine complexes, some complexes did exhibit mutagenic activity in the circumstances of this test, whereas others did not. this is comparable to the results known from the literature for ferrocene mediators. There was no specific correlation with the identities of the metal and ligand type; the possible explanations of the results are discussed in this paper. It seems probable that the penetration of the whole compound inside bacterial cells depends on the organic part of a complex, with only then the possible genotoxic activity of the complex being revealed. In view of our mutagenic test results, such complexes found to be mutagenic should not be taken into consideration as components of implanted glucose sensors in future in vivo experiments. 相似文献
998.
本文通过对烧伤病室隔离区不动杆菌无硝生物型感染流行病学调查,发现烧伤病人创面本菌的定植或感染高达42.59%,均为耐药菌株;对氨苄青霉素,头孢唑啉耐花分别达100%、95.7%。通过质粒图谱及限制性内切酶指纹图分析确定流行株菌质粒为22K、b26kb两种、是通过手接触与空气传播的。 相似文献
999.
Stephen F. Norton 《Environmental Biology of Fishes》1995,44(1-3):61-78
Synopsis One of the major goals of an ecomorphological analysis is to correlate patterns of interspecific differences in morphology with patterns of interspecific differences in ecology. Information derived from functional morphological studies may provide a mechanistic framework supporting the correlation, but the move from a correlational relationship to a causal relationship requires experimental evidence that the interspecific morphological differences create performance differences and therefore ecological differences. The goal of this study was to examine ecomorphological relationships in the diets of cottid fishes (Scorpaeniformes: Cottidae) from the northeastern Pacific by using functional classifications of predators (based on their mode of attack) and of prey (based on their anti-predator defenses). The proposed ecomorphological relationships were tested by examining capture success among the cottids in attacks on prey with different escape abilities. As predicted on functional morphological grounds, both multivariate and univariate analyses indicated that the gravimetric importance of elusive prey (i.e. fishes, shrimp, mysids, and octopods) was greater in cottid species with a larger relative mouth size. Supporting a causal link between morphology and ecology, performance tests indicated that larger-mouthed cottids had significantly higher capture success on Heptacarpus shrimp than did smaller-mouthed species. As predicted, there were no differences in capture success among predators regardless of their attack style or ecomorphological patterns in attack on crabs (Cancer and Petrolisthes spp.) when the crabs were presented on a sand surface (i.e. easy prey). Several difficulties still exist when trying to apply a functional group approach to ecomorphology. These include the behavioral plasticity of the predators, the confounding factor of evolutionary history in identifying correlated ecomorphological features, multiple morphological solutions to common functional problems, the limitations of traditional dietary studies during extremes of prey abundance, and an inadequate understanding of the anti- predator defenses of most prey, including modifications that occur during ontogeny or in different habitats. 相似文献
1000.
Akiyoshi Utsunomiya Daniel Elío-Calvo Armando Alberto Benitez Reyes Ernesto Sanzetenea Castro Enrique Rodríguez Carolina Tress Jenny I. Zamora de Corzo Erika Hannover Akemi Kai Kazumichi Tamura Naomi Higa 《Microbiology and immunology》1995,39(11):845-851
A total of 1,234 fecal samples from diarrhea cases were examined for etiological bacterial agents at medical facilities in La Paz and Sucre, Bolivia. Eighty strains of Shigella spp., 39 strains of Salmonella spp., 29 strains of Vibrio cholerae, and 222 strains of enteropathogenic Escherichia coli (139 EPEC, 55 ETEC, 29 EIEC, and 1 EHEC) were isolated. With regard to the serovars of Shigella, S. flexneri 2a, 3a, and 1b were predominant. In the case of Salmonella, S. enteritidis was the most common, followed by S. typhi, S. poona, and S. paratyphi B. Out of 29 cholera strains, 25 belonged to biovar El Tor, serovar Ogawa while the remaining 4 were serovar Inaba. Among 55 strains of ETEC serotypes, 5 showed ST producers but none showed LT producers. Likewise, among 55 strains of enterohemorrhagic serotypes, only one strain (O157:H7) produced verocytotoxin (VT 2). The results of drug sensitivity tests revealed the predominance of Shigella, EPEC, and ETEC strains resistant to aminobenzil-penicillin (ABPC) and trimethoprim. Since diarrheal patients in Bolivia are treated mainly with ABPC or sulfamethoxazole/trimethoprim (SXT) and rarely with gentamicin, kanamycin, or other drugs, it is possible that ABPC- and SXT-resistant strains will increase and persist in the near future. 相似文献