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51.
New host and geographical records are reported for the nematode Lappetascaris lutjani Rasheed, 1965, parasitizing the marine fish Trachipterus arawatae Clark, 1881 in Brazilian waters. Morphometric data and illustrations of the parasites are included. 相似文献
52.
Kanegusuku M Benassi JC Pedrosa RC Yunes RA Filho VC Maia AA de Souza MM Delle Monache F Niero R 《Zeitschrift für Naturforschung. C, Journal of biosciences》2002,57(3-4):272-276
Rubus imperialis, Artemia salina, 3-O-methylellagic-4'-O-alpha-rhamnose Acid Screening of different extracts, fractions and compounds from Rubus imperialis Chum. Schl. (Rosaceae) has been conduced using the brine shrimp microwell cytotoxicity assay. Three parts of the plant (methanolic extract from leaves, roots and stems), three fractions from roots (hexane, ethyl acetate and butanol) and three isolated compounds (niga-ichigoside F1, 23-hydroxytormentic acid, ellagic acid derivative) were tested. The most promising material (LC50 <1000 microg/ml) were the methanolic extract and ethyl acetate fraction from roots. However, there was little correlation observed in the degree of toxicities observed between the isolated compounds. On the other hand, the cytotoxicity and in vivo assays confirmed the hypoglycemic activity of methanolic extract and validated the Brazilian popular use of R. imperialis as an antidiabetic agent. 相似文献
53.
Aldehyde oxidase (AO) and xanthine oxidase (XO) are cytosolic enzymes that have been involved in some pathological conditions and play an important role in the biotransformation of drugs and xenobiotics. The increasing interest in these enzymes demands for a simple and rapid procedure for their purification. This paper describes for the first time a method that allows simultaneous purification of both enzymes from the same batch of rat livers. It involves few steps, is reproducible and offers high enzyme yields with high specific activities. The rat liver homogenate was fractionated by heat denaturation and by ammonium sulphate precipitation to give a crude extract containing both enzymes. This extract was chromatographed on an Hydroxyapatite column that completely separated AO from XO. Further purification of XO by anion exchange chromatography on a Q-Sepharose Fast Flow column resulted in a highly purified (1200-fold) preparation, with a specific activity of 3.64 U/mg and with a 20% yield. AO was purified about 1000-fold at a yield of 15%, with a specific activity of 3.48 U/mg, by affinity chromatography on Benzamidine-Sepharose 6B. The purified enzymes gave single bands of approximately 300 kDa on a polyacrylamide gel gradient electrophoresis and displayed the characteristic absorption spectra of highly purified enzymes. 相似文献
54.
Stationary phase mutagenesis: mechanisms that accelerate adaptation of microbial populations under environmental stress 总被引:4,自引:1,他引:3
Kivisaar M 《Environmental microbiology》2003,5(10):814-827
Microorganisms are exposed to constantly changing environmental conditions. In a growth-restricting environment (e.g. during starvation), mutants arise that are able to take over the population by a process known as stationary phase mutation. Genetic adaptation of a microbial population under environmental stress involves mechanisms that lead to an elevated mutation rate. Under stressful conditions, DNA synthesis may become more erroneous because of the induction of error-prone DNA polymerases, resulting in a situation in which DNA repair systems are unable to cope with increasing amounts of DNA lesions. Transposition may also increase genetic variation. One may ask whether the rate of mutation under stressful conditions is elevated as a result of malfunctioning of systems responsible for accuracy or are there specific mechanisms that regulate the rate of mutations under stress. Evidence for the presence of mutagenic pathways that have probably been evolved to control the mutation rate in a cell will be discussed. 相似文献
55.
Brandalise M Maia IG Borecký J Vercesi AE Arruda P 《Journal of bioenergetics and biomembranes》2003,35(3):203-209
An Arabidopsis thaliana cDNA clone encoding a plant uncoupling mitochondrial protein (AtPUMP1) was overexpressed in transgenic tobacco plants. Analysis of the AtPUMP1 mRNA content in the transgenic lines, determined by Northernblot, revealed variable levels of transgene expression. Antibody probing ofWestern blots of mitochondrial proteins from three independent transgenic lines showed significant accumulation of AtPUMP1 in this organelle. Overproduction of AtPUMP1 in transgenic tobacco plants led to a significantincrease in tolerance to oxidative stress promoted by exogenous hydrogen peroxide as compared to wild-type control plants. These results provide thefirst biological evidence for a role of PUMP in protection of plant cells against oxidative stress damage. 相似文献
56.
Siefert JL Larios-Sanz M Nakamura LK Slepecky RA Paul JH Moore ER Fox GE Jurtshuk P 《Current microbiology》2000,41(2):84-88
The phylogeny of 11 pigmented, aerobic, spore-forming isolates from marine sources was studied. Forty-two biochemical characteristics
were examined, and a 16S rDNA sequence was obtained for each isolate. In a phylogenetic tree based on 16S sequencing, four
isolates (NRRL B-14850, NRRL B-14904, NRRL B-14907, and NRRL B-14908) clustered with B. subtilis and related organisms; NRRL B-14907 was closely related to B. amyloliquefaciens. NRRL B-14907 and NRRL B-14908 were phenotypically similar to B. amyloliquefaciens and B. pumilus, respectively. Three strains (NRRL B-14906, NRRL B-14910, and NRRL B-14911) clustered in a clade that included B. firmus, B. lentus, and B. megaterium. NRRL B-14910 was closely related phenotypically and phylogenetically to B. megaterium. NRRL B-14905 clustered with the mesophilic round spore-producing species, B. fusiformis and B. sphaericus; the isolate was more closely related to B. fusiformis. NRRL B-14905 displayed characteristics typical of the B. sphaericus-like organisms. NRRL B-14909 and NRRL B-14912 clustered with the Paenibacillus species and displayed characteristics typical of the genus. Only NRRL B-14851, an unusually thin rod that forms very small
spores, may represent a new Bacillus species.
Received: 8 December 1999 / Accepted: 14 February 2000 相似文献
57.
Green M 《Culture, medicine and psychiatry》2000,24(4):403-430
This paper explores the changing institutional context of health servicedelivery in rural Tanzania through an anthropological analysis of thekinds of healing strategies pursued by men and women when they are ill.In some rural districts popular dissatisfaction with state medicalprovision is not manifested in a rejection of the allopathic medicinewith which it is associated, but in increased reliance on an emerginginformal sector of private medical provision. Although this sectorprovides a valued and accessible service to certain categories ofclients it delivers poor quality treatment, serving to reinforce thecyclical relationship between poverty and ill health. Despite the bestintentions of major public sector reforms neither government nor otheragencies are able to meet rural demand for health services. Reliance onthe parallel market for medical provision is likely to continue, atleast in the short term, with negative consequences for health. 相似文献
58.
59.
ApoE and clusterin cooperatively suppress Abeta levels and deposition: evidence that ApoE regulates extracellular Abeta metabolism in vivo 总被引:9,自引:0,他引:9
DeMattos RB Cirrito JR Parsadanian M May PC O'Dell MA Taylor JW Harmony JA Aronow BJ Bales KR Paul SM Holtzman DM 《Neuron》2004,41(2):193-202
Apolipoprotein E (apoE) and clusterin can influence structure, toxicity, and accumulation of the amyloid-beta (Abeta) peptide in brain. Both molecules may also be involved in Abeta metabolism prior to its deposition. To assess this possibility, we compared PDAPP transgenic mice that develop age-dependent Abeta accumulation in the absence of apoE or clusterin as well as in the absence of both proteins. apoE(-/-) and clusterin(-/-) mice accumulated similar Abeta levels but much less fibrillar Abeta. In contrast, apoE(-/-)/clusterin(-/-) mice had both earlier onset and markedly increased Abeta and amyloid deposition. Both apoE(-/-) and apoE(-/-)/clusterin(-/-) mice had elevated CSF and brain interstitial fluid Abeta, as well as significant differences in the elimination half-life of interstitial fluid Abeta measured by in vivo microdialysis. These findings demonstrate additive effects of apoE and clusterin on influencing Abeta deposition and that apoE plays an important role in regulating extracellular CNS Abeta metabolism independent of Abeta synthesis. 相似文献
60.
Pedro Paulo de Abreu Manso Barbara C. E. P. Dias de Oliveira Patrícia Carvalho de Sequeira Yuli Rodrigues Maia de Souza Jessica Maria dos Santos Ferro Igor José da Silva Luzia Fátima Gon?alves Caputo Priscila Tavares Guedes Alexandre Araujo Cunha dos Santos Marcos da Silva Freire Myrna Cristina Bonaldo Marcelo Pelajo-Machado 《PLoS neglected tropical diseases》2015,9(9)
The yellow fever (YF) 17D vaccine is one of the most effective human vaccines ever created. The YF vaccine has been produced since 1937 in embryonated chicken eggs inoculated with the YF 17D virus. Yet, little information is available about the infection mechanism of YF 17DD virus in this biological model. To better understand this mechanism, we infected embryos of Gallus gallus domesticus and analyzed their histopathology after 72 hours of YF infection. Some embryos showed few apoptotic bodies in infected tissues, suggesting mild focal infection processes. Confocal and super-resolution microscopic analysis allowed us to identify as targets of viral infection: skeletal muscle cells, cardiomyocytes, nervous system cells, renal tubular epithelium, lung parenchyma, and fibroblasts associated with connective tissue in the perichondrium and dermis. The virus replication was heaviest in muscle tissues. In all of these specimens, RT-PCR methods confirmed the presence of replicative intermediate and genomic YF RNA. This clearer characterization of cell targets in chicken embryos paves the way for future development of a new YF vaccine based on a new cell culture system. 相似文献