共查询到20条相似文献,搜索用时 0 毫秒
1.
Hydrogen exchange rates for backbone amide protons of oxidized Pseudomonas aeruginosa cytochrome c-551 (P. aeruginosa cytochrome c) have been measured in the presence of low concentrations of the denaturant guanidine hydrochloride. Analysis of the data
has allowed identification of submolecular unfolding units known as foldons. The highest-energy foldon bears similarity to
the proposed folding intermediate for P. aeruginosa cytochrome c. Parallels are seen to the foldons of the structurally homologous horse cytochrome c, although the heme axial methionine-bearing loop has greater local stability in P. aeruginosa cytochrome c, in accord with previous folding studies. Regions of low local stability are observed to correspond with regions that interact
with redox partners, providing a link between foldon properties and function.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
2.
Tianlei Ying Fangfang Zhong Jin Xie Yanjiao Feng Zhong-Hua Wang Zhong-Xian Huang Xiangshi Tan 《Journal of bioenergetics and biomembranes》2009,41(3):251-257
Conformational transitions in cytochrome c (cyt c) are being realized to be responsible for its multi-functions. Among a number of conformational transitions in cyt c, the alkaline transition has attracted much attention. The cDNA of human cyt c is cloned by RT-PCR and a high-effective expression system for human cyt c has been developed in this study. The equilibrium and kinetics of the alkaline transition of human cyt c have been systematically investigated for the first time, and compared with those of yeast and horse cyt c from an evolutionary perspective. The pKa value for the alkaline transition of human cyt c is apparently higher than that of yeast and horse. Kinetic studies suggest that it is increasingly difficult for the alkaline
transition of cyt c from yeast, horse and human. Molecular modeling of human cyt c shows that the omega loop where the lysine residue is located apparently further away from heme in human cyt c than in yeast iso-1 and horse heart cyt c. These results regarding alkaline conformational transition provide valuable information for understanding the molecular
basis for the biological multi-functions of cyt c. 相似文献
3.
There are three most important bacterial causative agents of serious infections that could be misused for warfare purposes:
Bacillus anthracis (the causative agent of anthrax) is the most frequently mentioned one; however, Fracisella tularensis (causing tularemia) and Yersinia pestis (the causative agent of plague) are further bacterial agents enlisted by Centers for Disease Control and Prevention into the category A of potential biological weapons. This review intends to summarize basic information about these bacterial
agents. Military aspects of their pathogenesis and the detection techniques suitable for field use are discussed. 相似文献
4.
5.
6.
Fang Wang Lijuan Lian Yunfeng Liu Yuman Zhang Rongxiang Fang Qinglin Liu 《中国科学:生命科学英文版》2018,61(12):1599-1601
7.
Kliphuis AM Janssen M van den End EJ Martens DE Wijffels RH 《Journal of applied phycology》2011,23(6):935-947
Respiration and photosynthesis are two important processes in microalgal growth that occur simultaneously in the light. To
know the rates of both processes, at least one of them has to be measured. To be able to measure the rate of light respiration
of Chlorella sorokiniana, the measurement of oxygen uptake must be fast, preferably in the order of minutes. We measured the immediate post-illumination
respiratory O2 uptake rate (OUR) in situ, using fiber-optic oxygen microsensors, and a small and simple extension of the cultivation system. This method enables rapid
and frequent measurements without disturbing the cultivation and growth of the microalgae. Two batch experiments were performed
with C. sorokiniana in a short light-path photobioreactor, and the OUR was measured at different time points. The net oxygen production rate
(net OPR) was measured online. Adding the OUR and net OPR gives the gross oxygen production rate (gross OPR), which is a measure
for the oxygen evolution by photosynthesis. The gross OPR was 35–40% higher than the net OPR for both experiments. The respiration
rate is known to be related to the growth rate, and it is suggested that faster algal growth leads to a higher energy (ATP)
requirement, and as such, respiratory activity increases. This hypothesis is supported by our results, as the specific OUR
is highest in the beginning of the batch culture when the specific growth rate is highest. In addition, the specific OUR decreases
toward the end of the experiments until it reaches a stable value of around 0.3 mmol O2 h−1 g−1. This value for the specific OUR is equal to the maintenance requirement of C. sorokiniana as determined in an independent study of (Zijffers et al. 2010 (in press)). This suggests that respiration could fulfill
the maintenance requirements of the microalgal cells. 相似文献
8.
A leaf beetle, Crioceris sp. (Coleoptera: Chrysomelidae), was introduced into Australia as a biological control agent of bridal creeper (Asparagus asparagoides L. Druce) during October 2002. Rearing of Crioceris sp. is labour intensive therefore all releases of Crioceris sp. have been under 1000 individuals, which may be too low to ensure establishment if high mortality and high competition
with other agents occurs. The aim of this study is to understand how the presence of two well-established biocontrol agents,
a rust fungus (Puccinia myrsiphylli (Thuem) Wint [Basidiomycota: Uredinales]) and a leafhopper (Zygina sp. [Hemiptera: Cicadellidae]), might influence Crioceris sp. establishment. Crioceris sp. neonate larvae were placed on bridal creeper plants with or without the leafhopper and/or rust. The number of larvae
that pupated was reduced by 38 and 65% in the presence of the rust fungus and leafhopper, respectively and by 45% in the presence
of both agents. As the area infected by the rust increased the area damaged by the leafhopper decreased. The rust appeared
to be negatively impacted by the presence of the leafhopper. In a second experiment, female Crioceris sp. adults were given a choice between uninfested bridal creeper plants and those infested with the rust or the leafhopper.
The females preferred to lay their eggs on plants without leafhoppers but did not seem to be deterred by the presence of the
rust. Consequently, the performance and impact of Crioceris sp. on bridal creeper may be reduced if populations overlap with the other biocontrol agents in the field. 相似文献
9.
S. Rehman A. S. Shawl A. Kour R. Andrabi P. Sudan P. Sultan V. Verma G. N. Qazi 《Applied Biochemistry and Microbiology》2008,44(2):203-209
The medicinal plant, Nothapodytes foetida, contains a number of important alkaloids like camptothecin (an anticancer drug molecule), but its concentration is less
to meet the existing demand of this important molecule, in an effort for accessible availability of camptothecin. An endophyte
(designated ZP5SE) was isolated from the seed of Nothapodytes foetida and was examined as a potential source of anticancer drug lead compound, i.e., camptothecin, when grown in Sabouraud liquid
culture media under shake flask conditions. The presence of an anticancer compound (camptothecin) in this fungus was confirmed
by chromatographic and spectroscopic methods in comparison with authentic camptothecin. Isolated endophyte (Neurospora crassa) producing camptothecin may become an easily accessible source for the production of a precursor anticancer drug molecule
in the future at a large scale.
Published in Russian in Prikladnaya Biokhimiya i Mikrobiologiya, 2008, Vol. 44, No. 2, pp. 225–231.
The text was submitted by the authors in English. 相似文献
10.
N. Yu. Markelova 《Microbiology》2010,79(6):777-779
Interaction of Bdellovibrio bacteriovorus 100NCJB with bacteria Campylobacter jejuni (strains 1, 2, 3, 4, and 5) and Helicobacter pylori, strain TX30a, was confirmed. The results indicate that lytic activity of bdellovibrios both in liquid media and cells attached
to a surface was observed. The potential use of the antimicrobial activity of predatory bacteria for environmental bioprotection
and public health is discussed. 相似文献
11.
Moslem Papizadeh Mohammad Roayaei Ardakani Gholamhossein Ebrahimipour Hossein Motamedi 《World journal of microbiology & biotechnology》2010,26(7):1195-1200
Oil-polluted soils were sampled from National Iranian South Oil Company (NISOC) for isolation and screening of C–S and not
C–C targeted Dibenzothiophene (DBT) degrading microorganisms. Microbacterium sp. NISOC-06, a C–S targeted DBT degrading bacterium, was selected and its desulfurization ability was studied in aqueous phase and water-gasoline
biphasic systems. The 16srRNA gene was amplified using universal eubacteria-specific primers, PCR product was sequenced and
the sequence of nearly 1,500 bp 16srDNA was studied. Based on Gas Chromatography results Microbacterium sp. NISOC-06 utilized 94.8% of 1 mM DBT during the 2 weeks of incubation. UV Spectrophotometry and biomass production measurements showed
that the Microbacterium sp. NISOC-06 was not able to utilize DBT as a carbon source. There was no accumulation of phenolic compounds as Gibb’s assay showed. Biomass
production in a biphasic system for which DBT-enriched gasoline was used as the sulfur source indicated the capability of
Microbacterium sp. NISOC-06 to desulfurize gasoline. 相似文献
12.
Giovanni La Penna Sara Furlan Lucia Banci 《Journal of biological inorganic chemistry》2007,12(2):180-193
Nuclear magnetic resonance experiments performed on yeast mitochondrial cytochrome c (Cytc), a paradigmatic electron transfer protein, reveal that the two oxidation states have similar structures, but different mobility:
despite the few structural differences compared with the reduced form, the oxidized form displays a larger unfolding propensity.
Molecular dynamics simulations performed on both NMR reduced and NMR oxidized forms show that the reduced form has a larger
solvent-accessible surface area (SASA). Starting from this observation, a molecular statistical approach was then applied
in order to correlate the molecular surface to molecular mobility. Simulations started from biased initial conditions corresponding
to different molecular sizes were combined with the maximal constrained entropy method. The NMR structure of oxidized Cytc is more suited to expose a smaller SASA than the NMR structure of the reduced form, but the accessible conformational landscape
at 300 K around the NMR oxidized structure is flatter than for the NMR reduced structure. Protein configurations of smaller
SASA and size display larger plasticity when they resemble the NMR oxidized structure, whereas they are more rigid when they
resemble the NMR reduced structure. Implications of the results for the protein properties during its functional process are
discussed.
Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users. 相似文献
13.
Nataša Tomášková Rastislav Varhač Gabriel Žoldák Lenka Olekšáková Dagmar Sedláková Erik Sedlák 《Journal of biological inorganic chemistry》2007,12(2):257-266
The alkaline isomerization of horse heart ferricytochrome c (cyt c) has been studied by electronic absorption spectroscopy in the presence of the Hofmeister series of anions: chloride, bromide,
rhodanide and perchlorate. The anions significantly affect the apparent pK
a value of the transition in a concentration-dependent manner according to their position in the Hofmeister series. The Soret
region of the absorption spectra is not affected by the presence of the salts and shows no significant structural perturbation
of the heme crevice. In the presence of perchlorate and rhodanide anions, the cyanide exchange rate between the bulk solvent
and the binding site is increased. These results imply higher flexibility of the protein structure in the presence of chaotropic
salts. The thermal and isothermal denaturations monitored by differential scanning calorimetry and circular dichroism, respectively,
showed a decrease in the conformational stability of cyt c in the presence of the chaotropic salts. A positive correlation between the stability, ΔG, of cyt c and the apparent pK
a values that characterize the alkaline transition indicates the presence of a thermodynamic linkage between these conformational
transitions. In addition, the rate constant of the cyanide binding and the partial molar entropies of anions negatively correlate
with the pK
a values. This indicates the important role of anion-induced solvent reorganization on the structural flexibility of cyt c in the alkaline transitions.
Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users. 相似文献
14.
Septobasidium parviflorae sp. nov. on Pinus parviflora is described and illustrated. This species is characterized by its whitish-gray, gray to dark gray-colored fungus body with
an indeterminate margin, hyphal strands, and cylindrical basidia with long sterigmata. This is the first report of Septobasidium occurring on a member of the genus Pinus in Japan. 相似文献
15.
Falk Zakrzewski Torsten Wenke Daniela Holtgräwe Bernd Weisshaar Thomas Schmidt 《BMC plant biology》2010,10(1):8
Background
Repetitive DNA is a major fraction of eukaryotic genomes and occurs particularly often in plants. Currently, the sequencing of the sugar beet (Beta vulgaris) genome is under way and knowledge of repetitive DNA sequences is critical for the genome annotation. We generated a c 0 t-1 library, representing highly to moderately repetitive sequences, for the characterization of the major B. vulgaris repeat families. While highly abundant satellites are well-described, minisatellites are only poorly investigated in plants. Therefore, we focused on the identification and characterization of these tandemly repeated sequences. 相似文献16.
O. V. Golovanova V. I. Konenkov A. V. Shevchenko M. V. Smolnikova 《Russian Journal of Genetics》2009,45(8):981-986
Based on population analysis of the DRB1, DQA1, DQB1 and TNFA allele frequency distribution patterns, regional features of immunogenetic structure of the population of West Siberia were
investigated. Statistically significant linkage disequilibrium within the HLA class II region, as well as between the TNFA and DRB1, DQA1, and DQB1 was demonstrated. Population frequency distribution patterns of two- and multilocus haplotypes were examined. 相似文献
17.
18.
19.