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排序方式: 共有181条查询结果,搜索用时 31 毫秒
141.
Cheryl A. Kerfeld Stephanie Yoshida Kimberlee T. Tran Todd O. Yeates Duilio Cascio Hervé Bottin Catherine Berthomieu Miwa Sugiura Alain Boussac 《Journal of biological inorganic chemistry》2003,8(7):707-714
The iron-containing superoxide dismutase (FeSOD) from the thermophilic cyanobacterium Thermosynechococcus elongatus has been isolated. The protein crystallizes readily and we have determined the structure to 1.6 A resolution. This is the first structural characterization of an FeSOD isolated from a cyanobacterium and one of the highest resolution FeSOD structures determined to date. The activity of the T. elongatus FeSOD has been measured both at 25 degrees C and 50 degrees C and it has been spectroscopically characterized. The T. elongatus FeSOD EPR spectra at pH 5.1, 7.5 and 10.0 are similar. This indicates that no change in the geometry of the Fe(III) site occurs over a wide range of pH. This is in contrast to the other FeSODs described in the literature. 相似文献
142.
Some species of the genus Amanita are economically important gourmet mushrooms, while others cause dramatic poisonings or even deaths every year in China and in many other countries. A DNA barcode is a short segment or a combination of short segments of DNA sequences that can distinguish species rapidly and accurately. To establish a standard DNA barcode for poisonous species of Amanita in China, three candidate markers, the large subunit nuclear ribosomal RNA (nLSU), the internal transcribed spacer (ITS), and the translation elongation factor 1 alpha (tef1 α) were tested using the eukaryotic general primers for their feasibility as barcodes to identify seven species of lethal fungi and two species of edible ones which can easily be confused with the lethal ones known from China. In addition, A.phalloides—a European and North American species closely related to one of the seven taxa, A.subjunquillea was also included. PCR amplification and sequencing success rate, intra and inter specific variation and rate of species identification were considered as main criteria for evaluation of the candidate DNA barcodes. Although the nLSU had high PCR and sequencing success rates (100% and 100% respectively), occasional overlapping occurred between the intra and inter specific variations. The PCR amplification and sequencing success rates of ITS were 100% and 85.7% respectively. ITS showed high sequence variation among species group and low variation within a given species. There was a relatively high PCR amplification and sequencing success rate for tef1 α (85.7% and 100% respectively), and its intra and inter specific variation was higher than that of ITS or nLSU. All three candidate markers showed hight species resolution. ITS and tef1 α had a more clearly defined barcode gap than nLSU. Our study showed that the tef1 α and nLSU can be proposed as supplementary barcodes for the genus Amanita, while ITS can be used as a primary barcode marker considering that the ITS region may become a universal barcode marker for the fungal kingdom. 相似文献
143.
YU Ya-Ying- SHAO Gao-Neng- SHENG Zhong-Hua- JIANG Han-Wei- HE Ji-Wai- SUN Yuan-Yuan- CA Yi-Cong- HU Pei-Song- TANG Shao-Qing 《Plant Diversity》2015,37(6):871-880
Genetic diversity of 434 rice accessions collected from 16 countries, including 345 fragrance rice varieties and 89 non fragrance rice varieties, have been analyzed. A total of 573 alleles were detected by using 77 simple sequence repeats (SSR) primer pairs covering all rice 12 chromosomes. The value of allelic polymorphism information content (PIC) ranged from 0090 to 0845, with an average of 0516 per locus; Gene diversity (GD) varied from 0091 to 0859, with an average of 0573; The mean value of major allele frequencies (MAF) was 0540, covering from 0251 to 0953. In addition, 434 rice accessions are divided into three sub populations by cluster and population structure analysis, and FST between sub populations showed a mean of -0116, ranging from -0623 to 0494; The score of genetic distance calculated by Nei′s method appeared from 0207 to 0355. Major allele frequencies within each sub population distributed from 0408 to 0746, and gene diversity level from 0354 to 0699, while PIC from 0320 to 0658. Sequencing 6 mitochondrion genes in 18 rice varieties exhibited no different in 5 genes, whereas Mit4 contains a 3 SNPs in the gene body, which acts as an important marker to understanding the relationship between Indica/Japonica differentiation and the evolution of fragrant gene. Finally, genetic diversity and mitochondrion gene sequencing would help to know about the origin of fragrant resource and benefit rice breeding. 相似文献
144.
145.
目的:探讨SOCS-3在非酒精性脂肪肝病(NAFLD)发病中的作用以及吡格列酮的干预作用。方法:29只雄性SD大鼠随机分为正常对照组(8只),高脂饮食组(21只)。饲养8周后,从高质饮食组随机抽取5只大鼠证实造模成功后,将该组余下的16只大鼠继续以高脂饲料喂养,并随机分为NAFLD对照组(8只);吡格酮干预组(8只),予以吡格列酮3mg·kg^-1·d^-1灌胃。16周末,处死所有大鼠,检测血糖、血胰岛素、血脂、肝脏SOCS-3mRNA和SREBP-lcmRNA表达及肝脏病理学。结果:与正常对照组相比,NAFLD组血糖、血胰岛素、血脂、肝脏脂肪变水平及肝组织SOCS-3mRNA、SREBPlCmRNA表达显著上调。吡格列酮干预组sOCS.3mRNA、SREBP-1cmRNA表达较NAFLD组下调,且血糖、血胰岛素、血脂、肝脏脂肪变水平下降。SOCS-3mRNA表达水平与胰岛素抵抗指数、SREBP.1cmRNA表达水平、肝脂肪变成显著正相关。结论:SOCS-3可能通过胰岛素抵抗及上调肝组织SREBP-lcmRNA表达参与NAFLD发病,吡格列酮能抑制肝脏SOCS-3的表达,对NAFLD有一定治疗作用。 相似文献
146.
147.
Gordon C. Cannon Sabine Heinhorst Cheryl A. Kerfeld 《Biochimica et Biophysica Acta - Proteins and Proteomics》2010,1804(2):382-392
Cyanobacteria and some chemoautotrophic bacteria are able to grow in environments with limiting CO2 concentrations by employing a CO2-concentrating mechanism (CCM) that allows them to accumulate inorganic carbon in their cytoplasm to concentrations several orders of magnitude higher than that on the outside. The final step of this process takes place in polyhedral protein microcompartments known as carboxysomes, which contain the majority of the CO2-fixing enzyme, RubisCO. The efficiency of CO2 fixation by the sequestered RubisCO is enhanced by co-localization with a specialized carbonic anhydrase that catalyzes dehydration of the cytoplasmic bicarbonate and ensures saturation of RubisCO with its substrate, CO2. There are two genetically distinct carboxysome types that differ in their protein composition and in the carbonic anhydrase(s) they employ. Here we review the existing information concerning the genomics, structure and enzymology of these uniquely adapted carbonic anhydrases, which are of fundamental importance in the global carbon cycle. 相似文献
148.
Martin A Short Naomi Campanale Sara Litwak Claude CA Bernard 《Cell Adhesion & Migration》2011,5(5):373-381
Bone marrow has been proposed as a possible source of cells capable of replacing injured neural cells in diseases such as Multiple Sclerosis (MS). Previous studies have reported conflicting results regarding the transformation of bone marrow cells into neural cells in vivo. This study is a detailed analysis of the fate of bone marrow derived cells (BMDC) in the CNS of C57Bl/6 mice with and without experimental autoimmune encephalomyelitis using flow cytometry to identify GFP-labeled BMDC that lacked the pan-hematopoietic marker CD45 and co-expressed neural markers polysialic acid-neural cell adhesion molecule or A2B5. A small number of BMDC displaying neural markers and lacking CD45 expression was identified within both the non-inflamed and inflamed CNS. However, the majority of BMDC exhibited a hematopoietic phenotype.Key words: bone marrow, transplantation, transdifferentiation, central nervous system, green fluorescence protein, experimental autoimmune encephalomyelitis, multiple sclerosis 相似文献
149.
ROBIN ENGLER CHRISTOPHE F. RANDIN WILFRIED THUILLER STEFAN DULLINGER NIKLAUS E. ZIMMERMANN MIGUEL B. ARAÚJO PETER B. PEARMAN GWENAËLLE LE LAY CHRISTIAN PIEDALLU CÉCILE H. ALBERT PHILIPPE CHOLER GHEORGHE COLDEA XAVIER
De LAMO THOMAS DIRNBÖCK JEAN‐CLAUDE GÉGOUT DANIEL GÓMEZ‐GARCÍA JOHN‐ARVID GRYTNES EINAR HEEGAARD FRIDE HØISTAD DAVID NOGUÉS‐BRAVO SIGNE NORMAND MIHAI PUŞCAŞ MARIA‐TERESA SEBASTIÀ ANGELA STANISCI JEAN‐PAUL THEURILLAT MANDAR R. TRIVEDI PASCAL VITTOZ ANTOINE GUISAN 《Global Change Biology》2011,17(7):2330-2341
Continental‐scale assessments of 21st century global impacts of climate change on biodiversity have forecasted range contractions for many species. These coarse resolution studies are, however, of limited relevance for projecting risks to biodiversity in mountain systems, where pronounced microclimatic variation could allow species to persist locally, and are ill‐suited for assessment of species‐specific threat in particular regions. Here, we assess the impacts of climate change on 2632 plant species across all major European mountain ranges, using high‐resolution (ca. 100 m) species samples and data expressing four future climate scenarios. Projected habitat loss is greater for species distributed at higher elevations; depending on the climate scenario, we find 36–55% of alpine species, 31–51% of subalpine species and 19–46% of montane species lose more than 80% of their suitable habitat by 2070–2100. While our high‐resolution analyses consistently indicate marked levels of threat to cold‐adapted mountain florae across Europe, they also reveal unequal distribution of this threat across the various mountain ranges. Impacts on florae from regions projected to undergo increased warming accompanied by decreased precipitation, such as the Pyrenees and the Eastern Austrian Alps, will likely be greater than on florae in regions where the increase in temperature is less pronounced and rainfall increases concomitantly, such as in the Norwegian Scandes and the Scottish Highlands. This suggests that change in precipitation, not only warming, plays an important role in determining the potential impacts of climate change on vegetation. 相似文献
150.
CA Campbell AR Horvath 《The Clinical biochemist. Reviews / Australian Association of Clinical Biochemists》2012,33(4):149-160
Timely release and communication of critical test results may have significant impact on medical decisions and subsequent patient outcomes. Laboratories therefore have an important responsibility and contribution to patient safety. Certification, accreditation and regulatory bodies also require that laboratories follow procedures to ensure patient safety, but there is limited guidance on best practices. In Australasia, no specific requirements exist in this area and critical result reporting practices have been demonstrated to be heterogeneous worldwide.Recognising the need for agreed standards and critical limits, the AACB started a quality initiative to harmonise critical result management throughout Australasia. The first step toward harmonisation is to understand current laboratory practices. Fifty eight Australasian laboratories responded to a survey and 36 laboratories shared their critical limits. Findings from this survey are compared to international practices reviewed in various surveys conducted elsewhere. For the successful operation of a critical result management system, critical tests and critical limits must be defined in collaboration with clinicians. Reporting procedures must include how critical results are identified; who can report and who can receive critical results; what is an acceptable timeframe within which results must be delivered or, if reporting fails, what escalation procedures should follow; what communication channels or systems should be used; what should be recorded and how; and how critical result procedures should be maintained and evaluated to assess impact on outcomes.In this paper we review the literature of current standards and recommendations for critical result management. Key elements of critical result reporting are discussed in view of the findings of various national surveys on existing laboratory practices, including data from our own survey in Australasia. Best practice recommendations are made that laboratories are expected to follow in order to provide high quality and safe service to patients. 相似文献