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111.
When Rhodopseudomonas capsulata B10 grows in media with different organic compounds, the hydrogenase activity estimated both by the evolution and uptake of H2 is lowest in cells taken from the middle of the exponential growth phase, and highest in cells from the beginning of the stationary phase. Cells grown in a medium containing malate have a higher hydrogenase activity than those cultivated in a medium with lactate or other compounds (900 and 20 nmoles of H2 per 1 min per 1 mg of protein, respectively). In the experiments with chloramphenicol (10(-5) M), organic compounds (not CO2) were shown to repress hydrogenase synthesis. When the cells were incubated in a medium without an organic substrate or in its presence, the exogenous H2 or H2 evolved as the result of nitrogenase action causes an increase in the activity of hydrogenase. 相似文献
112.
Hydrogen photoproduction by Rhodobacter sphaeroides immobilised on polyurethane foam 总被引:1,自引:0,他引:1
H2 photoproduction by Rhodobacter sphaeroides GL-1 immobilised on polyurethane foam in a continuous flow photobioreactor was shown to occur for prolonged periods. Under optimal conditions (300 W m–2; dilution rate 0.023 h–1) the rate of H2 production was 0.21 ml h–1 ml–1 foam matrix with an efficiency for lactic acid to H2 conversion of 86%. The duration of the process (35 days of operation) showed no major limitations. © Rapid Science Ltd. 1998 相似文献
113.
André M Siqueira Lucas I Coutinho Rafael L Gurgel Willian CS Su Luiz M Carvalho Silvana G Benzecry Aline CC Alencar Márcia AA Alexandre Maria Gra?as C Alecrim Marcus VG Lacerda 《Memórias do Instituto Oswaldo Cruz》2014,109(5):540-545
Plasmodium vivax is the most widespread parasite causing malaria, being
especially prevalent in the Americas and Southeast Asia. Children are one of the
most affected populations, especially in highly endemic areas. However, there are
few studies evaluating the therapeutic response of infants with vivax malaria.
This study retrospectively evaluated the parasitaemia clearance in children
diagnosed with vivax malaria during the first five days of exclusive treatment
with chloroquine (CQ). Infants aged less than six months old had a significantly
slower parasitaemia clearance time compared to the group of infants and children
between six months and 12 years old (Kaplan-Meier survival analysis; Wilcoxon
test; p = 0.004). The impaired clearance of parasitaemia in younger children with
vivax malaria is shown for the first time in Latin America. It is speculated that
CQ pharmacokinetics in young children with vivax malaria is distinct, but this
specific population may also allow the detection of CQ-resistant parasites during
follow-up, due to the lack of previous immunity. 相似文献
114.
Sergey Kosourov Hannu Leino Gayathri Murukesan Fiona Lynch Kaarina Sivonen Anatoly A. Tsygankov Eva-Mari Aro Yagut Allahverdiyeva 《Applied and environmental microbiology》2014,80(18):5807-5817
We have investigated two approaches to enhance and extend H2 photoproduction yields in heterocystous, N2-fixing cyanobacteria entrapped in thin alginate films. In the first approach, periodic CO2 supplementation was provided to alginate-entrapped, N-deprived cells. N deprivation led to the inhibition of photosynthetic activity in vegetative cells and the attenuation of H2 production over time. Our results demonstrated that alginate-entrapped ΔhupL cells were considerably more sensitive to high light intensity, N deficiency, and imbalances in C/N ratios than wild-type cells. In the second approach, Anabaena strain PCC 7120, its ΔhupL mutant, and Calothrix strain 336/3 films were supplemented with N2 by periodic treatments of air, or air plus CO2. These treatments restored the photosynthetic activity of the cells and led to a high level of H2 production in Calothrix 336/3 and ΔhupL cells (except for the treatment air plus CO2) but not in the Anabaena PCC 7120 strain (for which H2 yields did not change after air treatments). The highest H2 yield was obtained by the air treatment of ΔhupL cells. Notably, the supplementation of CO2 under an air atmosphere led to prominent symptoms of N deficiency in the ΔhupL strain but not in the wild-type strain. We propose that uptake hydrogenase activity in heterocystous cyanobacteria not only supports nitrogenase activity by removing excess O2 from heterocysts but also indirectly protects the photosynthetic apparatus of vegetative cells from photoinhibition, especially under stressful conditions that cause an imbalance in the C/N ratio in cells. 相似文献
115.
Uwe Thissen Suzan Wopereis Sjoerd AA van den Berg Ivana Bobeldijk Robert Kleemann Teake Kooistra Ko Willems van Dijk Ben van Ommen Age K Smilde 《BMC bioinformatics》2009,10(1):52
Background
In the fields of life sciences, so-called designed studies are used for studying complex biological systems. The data derived from these studies comply with a study design aimed at generating relevant information while diminishing unwanted variation (noise). Knowledge about the study design can be used to decompose the total data into data blocks that are associated with specific effects. Subsequent statistical analysis can be improved by this decomposition if these are applied on selected combinations of effects. 相似文献116.
Various methods currently used in microbiology for determining taxonomic state of bacteria are discussed. The main focus is aimed at identifying and gene typing of lactic acid bacteria, used as starter cultures for industrial process of production of sour milk products, meat products, and probiotics. 相似文献
117.
The proto-oncogenic protein c-Cbl was discovered as the cellular form of v-Cbl, a retroviral transforming protein. This was followed over the years by important discoveries, which identified c-Cbl and other Cbl-family proteins as key players in several signaling pathways. c-Cbl has donned the role of a multivalent adaptor protein, capable of interacting with a plethora of proteins, and has been shown to positively influence certain biological processes. The identity of c-Cbl as an E3 ubiquitin ligase unveiled the existence of an important negative regulatory pathway involved in maintaining homeostasis in protein tyrosine kinase (PTK) signaling. Recent years have also seen the emergence of novel regulators of Cbl, which have provided further insights into the complexity of Cbl-influenced pathways. This review will endeavor to provide a summary of current studies focused on the effects of Cbl proteins on various biological processes and the mechanism of these effects. The major sections of the review are as follows: Structure and genomic organization of Cbl proteins; Phosphorylation of Cbl; Interactions of Cbl; Localization of Cbl; Mechanism of effects of Cbl: (a) Ubiquitylation-dependent events: This section elucidates the mechanism of Cbl-mediated downregulation of EGFR and details the PTK and non-PTKs targeted by Cbl. In addition, it addresses the functional requirements for E3 Ubiquitin ligase activity of Cbl and negative regulation of Cbl-mediated downregulation of PTKs, (b) Adaptor functions: This section discusses the mechanisms of adaptor functions of Cbl in mitogen-activated protein kinase (MAPK) activation, insulin signaling, regulation of Ras-related protein 1 (Rap1), PI-3' kinase signaling, and regulation of Rho-family GTPases and cytoskeleton; Biological functions: This section gives an account of the diverse biological functions of Cbl and includes the role of Cbl in transformation, T-cell signaling and thymus development, B-cell signaling, mast-cell degranulation, macrophage functions, bone development, neurite growth, platelet activation, muscle degeneration, and bacterial invasion; Conclusions and perspectives. 相似文献
118.
The XI International Rotifer Symposium was held during 11–18 March, 2006 at the National Autonomous University of Mexico Campus Iztacala located at the North Mexico City (Mexico). These triennial international meetings, first organized in Austria by Late Ruttner-Kolisko in September 1976, are gradually becoming the focal point of discussion and collaboration from rotifer workers across the world. The present XI symposium was attended by 125 participants from 20 nations. During this meeting, different themes of rotifer research from morphology to molecular biology were considered. In addition, there were four invited lectures and four workshops covering different themes of the symposium. During the last 30 years, rotifer research has witnessed gradual shift from the conventional morphological taxonomy to molecular and evolutionary systematics. While the basic rotifer ecological studies continue today, applied areas such as ecotoxicology and aquaculture have taken key roles in the recent meetings. The international rotifer meetings provide ample opportunities not only for exchange of ideas and recent research, but also for material and in establishing inter-personal relationships. Over the last 30 years, the number of participants attending the rotifer meetings has increased. 相似文献
119.
土壤中棉花黄萎病菌SYBR Green Ⅰ荧光RT-PCR定量检测技术研究 总被引:3,自引:1,他引:2
为实现田间土壤棉花黄萎病菌的早期检测,建立了土壤中棉花黄萎病菌的SYBR GreenⅠ荧光定量PCR检测方法.以含342bp PCR扩增产物的阳性质粒为参考,构建了标准曲线,并对该曲线的特异性、敏感性、可重复性进行了评价.结果表明,该方法具有快速、特异性强、敏感度高等特点.检测范围在3.8×103-3.8×108cop... 相似文献
120.
Visualization and analysis of molecular networks are both central to systems biology. However, there still exists a large technological gap between them, especially when assessing multiple network levels or hierarchies. Here we present RedeR, an R/Bioconductor package combined with a Java core engine for representing modular networks. The functionality of RedeR is demonstrated in two different scenarios: hierarchical and modular organization in gene co-expression networks and nested structures in time-course gene expression subnetworks. Our results demonstrate RedeR as a new framework to deal with the multiple network levels that are inherent to complex biological systems. RedeR is available from http://bioconductor.org/packages/release/bioc/html/RedeR.html. 相似文献