共查询到20条相似文献,搜索用时 15 毫秒
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Cristina Mendes Rute Felix Ana-Margarida Sousa Joana Lamego Derek Charlwood Virgílio E do Rosário João Pinto Henrique Silveira 《BMC evolutionary biology》2010,10(1):9
Background
Immune responses to parasites, which start with pathogen recognition, play a decisive role in the control of the infection in mosquitoes. Peptidoglycan recognition proteins (PGRPs) are an important family of pattern recognition receptors that are involved in the activation of these immune reactions. Pathogen pressure can exert adaptive changes in host genes that are crucial components of the vector's defence. The aim of this study was to determine the molecular evolution of the three short PGRPs (PGRP-S1, PGRP-S2 and PGRP-S3) in the two main African malaria vectors - Anopheles gambiae and Anopheles arabiensis. 相似文献3.
A. How Kit L. Boureau L. Stammitti-Bert D. Rolin E. Teyssier P. Gallusci 《Plant molecular biology》2010,74(3):201-213
The Enhancer of Zeste (E(z)) Polycomb group (PcG) proteins, which are encoded by a small gene family in Arabidopsis thaliana, have been shown to participate to the control of flowering and seed development. For the time being, little is known about
the function of these proteins in other plants. In tomato E(z) proteins are encoded by at least two genes namely SlEZ1 and SlEZ2 while a third gene, SlEZ3, is likely to encode a truncated non-functional protein. The analysis of the corresponding mRNA demonstrates that these two
genes are differentially regulated during plant and fruit development. We also show that SlEZ1 and SlEZ2 are targeted to the
nuclei. These results together with protein sequence analysis makes it likely that both proteins are functional E(z) proteins.
The characterisation of SlEZ1 RNAi lines suggests that although there might be some functional redundancy between SlEZ1 and SlEZ2 in most plant organs,
the former protein is likely to play specific function in flower development. 相似文献
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Alethia A. Hostetter Michelle L. Miranda Victoria J. DeRose Karen L. McFarlane Holman 《Journal of biological inorganic chemistry》2011,16(8):1177-1185
[ImH][trans-RuIIICl4(DMSO)(Im)] (where DMSO is dimethyl sulfoxide and Im is imidazole) (NAMI-A) is an antimetastatic prodrug currently in phase
II clinical trials. The mechanisms of action of this and related Ru-based anticancer agents are not well understood, but several
cellular targets have been suggested. Although Ru has been observed to bind to DNA following in vitro NAMI-A exposure, little
is known about Ru–DNA interactions in vivo and even less is known about how this or related metallodrugs might influence cellular
RNA. In this study, Ru accumulation in cellular RNA was measured following treatment of Saccharomyces cerevisiae with NAMI-A. Drug-dependent growth and cell viability indicate relatively high tolerance, with approximately 40% cell death
occurring at 6 h for 450 μM NAMI-A. Significant dose-dependent accumulation of Ru in cellular RNA was observed by inductively coupled plasma mass spectrometry
measurements on RNA extracted from yeast treated with NAMI-A. In vitro, binding of Ru species to drug-treated model DNA and
RNA oligonucleotides at pH 6.0 and 7.4 was characterized by matrix-assisted laser desorption/ionization time-of-flight mass
spectrometry in the presence and absence of the reductant ascorbate. The extent of Ru–nucleotide interactions increases slightly
with lower pH and significantly in the presence of ascorbate, with differences in observed species distribution. Taken together,
these studies demonstrate the accumulation of aquated and reduced derivatives of NAMI-A on RNA in vitro and in cellulo, and
enhanced binding with nucleic acid targets in a tumorlike acidic, reducing environment. To our knowledge, this is also the
first study to characterize NAMI-A treatment of S. cerevisiae, a genetically tractable model organism. 相似文献
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Several Gram-negative bacterial pathogens have developed type III secretion systems (T3SSs) to deliver virulence proteins
directly into eukaryotic cells in a process essential for many diseases. The type III secretion processes require customized
chaperones with high specificity for binding partners, thus providing the secretion to occur. Due to the very low sequence
similarities among secretion chaperones, annotation and discrimination of a great majority of them is extremely difficult
and a task with low scores even if genes are encountered that codify for small (<20 kDa) proteins with low pI and a tendency
to dimerise. Concerning about this, herein, we present structural features on two hypothetical T3SSs chaperones belonging
to plant pathogen Xanthomonas axonopodis pv. citri and suggest how low resolution models based on Small Angle X-ray Scattering patterns can provide new structural insights
that could be very helpful in their analysis and posterior classification. 相似文献
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Huiming Duan Sirajo Umar Yiping Hu Jinchun Chen 《World journal of microbiology & biotechnology》2009,25(10):1779-1783
We constructed a Pichia pastoris expression vector with two strongly inducible promoters (an alcohol oxidase 1 promoter and a formaldehyde dehydrogenase 1
promoter) based on pPIC9 k. To test the function of these promoters, the vector was used to co-express two genes that encode
for green fluorescent protein (GFP) and a portion of a gelatin gene (an intra- and extracellular protein). The gelatin gene
was placed under the control of PAOX1, while the GFP was under the control of PFLD1. The two proteins were simultaneously expressed upon induction with 0.5% (v/v) methanol. The two promoters functioned effectively
and their coexistence on one vector did not affect their efficiency in protein expression. Thus, it was possible to simultaneously
induce the expression of at least two proteins from one vector, using two different promoters. 相似文献
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Telomeric DNA-binding proteins (TBPs) are crucial components that regulate the structure and function of eukaryotic telomeres and are evolutionarily conserved. We have identified two homologues of AtTBP1 (for Arabidopsis thaliana telomeric DNA binding protein 1), designated as AtTBP2 and AtTRP2, which encode proteins that specifically bind to the telomeric DNA of this plant. These proteins show extensive homology with other known plant TBPs. The isolated C-terminal segments of these proteins were capable of sequence-specific binding to duplex telomeric plant DNA in vitro. DNA bending assays using the Arabidopsis TBPs revealed that AtTBP1 and AtTBP2 have DNA-bending abilities comparable to that of the human homologue hTRF1, and higher than those of AtTRP1 and AtTRP2. 相似文献
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Castillo Ruiz RA Herrera C Ghislain M Gebhardt C 《Molecular genetics and genomics : MGG》2005,274(2):168-179
Defence-response (DR) genes are candidates for the genetic functions underlying quantitative resistance to plant pathogens.
The organization of three DR gene families encoding phenylalanine ammonia lyase (PAL), acidic PR-(pathogenesis-related) protein
5, and basic PR-5, or osmotin-like (OSM), proteins was studied in the potato genome. A bacterial artificial chromosome (BAC)
library containing ~50,000 clones was constructed from high-molecular weight genomic DNA of the diploid potato clone PD59,
a hybrid between Solanum tuberosum and S. phureja. BAC clones carrying one or more copies of the DR genes were identified and characterized by Southern hybridization, sequence
analysis and genetic mapping. PAL, acidic PR-5 and OSM (basic PR-5) genes were all organized into gene families of varying complexity. The PAL gene family consisted of at least 16 members, several of which were physically linked. Four acidic PR-5 homologous were localized to a 45-kb segment on potato chromosome XII. One of these, PR-5/319, codes for the acidic thaumatin-like protein C found in intercellular fluids of potato. Nine OSM genes were organized at two loci: eight form a 90-kb cluster on chromosome VIII, and a single gene was found on chromosome
XI. The topology of a phylogenetic tree based on PR-5 and OSM protein sequences from Solanaceae suggests a mode of evolution
for these gene families. The results will form the basis for further studies on the potential role of these defence-related
loci in quantitative resistance to pathogens. 相似文献
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Background
Large fractions of all fully sequenced genomes code for proteins of unknown function. Annotating these proteins of unknown function remains a critical bottleneck for systems biology and is crucial to understanding the biological relevance of genome-wide changes in mRNA and protein expression, protein-protein and protein-DNA interactions. The work reported here demonstrates that de novo structure prediction is now a viable option for providing general function information for many proteins of unknown function. 相似文献12.
Abdullah I. Abdallah Nicola J. Commander Martin J. Woodward Steve Spencer C. Anthony Hart Craig Winstanley 《Current microbiology》2003,46(4):0241-0245
Protein sequences from characterized type III secretion (TTS) systems were used as probes in silico to identify several TTS
gene homologs in the genome sequence of Brucella suis biovar 1 strain 1330. Four of the genes, named flhB, fliP, fliR, and fliF on the basis of greatest homologies to known flagellar apparatus proteins, were targeted in PCR and hybridization assays
to determine their distribution among other Brucella nomen species and biovars. The results indicated that flhB, fliP, fliR and fliF are present in Brucella melitensis, Brucella ovis, and Brucella suis biovars 1, 2 and 3. Similar homologos have been reported previously in Brucella abortus. Using RT-PCR assays, we were unable to detect any expression of these genes. It is not yet known whether the genes are the
cryptic remnants of a flagellar system or are actively involved in a process contributing to pathogenicity or previously undetected
motility, but they are distributed widely in Brucella and merit further study to determine their role.
Received: 11 February 2002 / Accepted: 13 June 2002 相似文献
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Elizabeth Fullam Akane Kawamura Helen Wilkinson Areej Abuhammad Isaac Westwood Edith Sim 《The protein journal》2009,28(6):281-293
Arylamine N-acetyltansferase (NAT) from Mycobacterium tuberculosis (TBNAT) is a potential drug target for anti-tubercular therapy. Recombinant TBNAT is much less soluble and is produced in
lower yields than the closely related NAT from Mycobacterium marinum (MMNAT). In order to explore MMNAT as a model for TBNAT in drug discovery, we compare the two mycobacterial NAT enzymes.
Two site-directed mutants of MMNAT have been prepared and characterised: MMNAT71, Tyr → Phe and MMNAT209, Met → Thr, in which
residues within 6 Å of the active-site cysteine have been replaced with the corresponding residue from TBNAT. Two chimeric
proteins have also been produced in which the third domain of MMNAT has been replaced by the third domain of TBNAT and vice
versa. The activity profile of the chimeric proteins suggests a role for the third domain in the evolutionary divergence of
NAT between these closely related mycobacterial species. 相似文献
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Zhehao Chen Mengting Li Ye Yuan Jiangqin Hu Yanjun Yang Jiliang Pang Lilin Wang 《Plant Cell, Tissue and Organ Culture》2017,131(1):107-118
Auxin receptors TIR1/AFBs play an essential role in a series of signaling network cascades. These F-box proteins have also been identified to participate in different stress responses via the auxin signaling pathway in Arabidopsis. Cucumber (Cucumis sativus L.) is one of the most important crops worldwide, which is also a model plant for research. In the study herein, two cucumber homologous auxin receptor F-box genes CsTIR and CsAFB were cloned and studied for the first time. The deduced amino acid sequences showed a 78% identity between CsTIR and AtTIR1 and 76% between CsAFB and AtAFB2. All these proteins share similar characteristics of an F-box domain near the N-terminus, and several Leucine-rich repeat regions in the middle. Arabidopsis plants ectopically overexpressing CsTIR or CsAFB were obtained and verified. Shorter primary roots and more lateral roots were found in these transgenic lines with auxin signaling amplified. Results showed that expression of CsTIR/AFB genes in Arabidopsis could lead to higher seeds germination rates and plant survival rates than wild-type under salt stress. The enhanced salt tolerance in transgenic plants is probably caused by maintaining root growth and controlling water loss in seedlings, and by stabilizing life-sustaining substances as well as accumulating endogenous osmoregulation substances. We proposed that CsTIR/AFB-involved auxin signal regulation might trigger auxin mediated stress adaptation response and enhance the plant salt stress resistance by osmoregulation. 相似文献
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Microbial bioreduction of radionuclides has been the subject of much recent interest, in particular as a method for the in
situ bioremediation of uranium contaminated sites. However, there have been very few studies investigating the microbially
mediated redox transformations of plutonium. The redox chemistry of Pu is complicated, but the dominant environmental oxidation
state is insoluble Pu(IV). However, microbial reduction of Pu(IV) to more soluble Pu(III) may enhance migration of Pu in the
environment. In this study we investigated the effect of two model metal-reducing bacteria, Geobacter sulfurreducens and Shewanella oneidensis, on the redox speciation of Pu. Our results show that in all cases, the presence of bacterial cells enhanced removal of Pu
from solution. UV/Visible spectra of cells and precipitates formed (dissolved in 1 M HCl), showed that the sorbed and precipitated
Pu was mainly Pu(IV), but Pu(III) was also present. The results suggest that the mechanism of interaction between Pu(IV) and
the two microorganisms is initial sorption to the cell surface, followed by slow reduction. Although both bacteria could reduce
Pu(IV) to Pu(III), there was no increase in the solution concentrations of Pu. This suggests that the potential reduction
of sorbed Pu(IV) in sediments that have been stimulated to bioremediate U(VI) may not result in problematic mobilization of
Pu(III). 相似文献
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Ant-gardens represent a special type of association between ants and epiphytes. Frequently, two ant species can share the
same nest in a phenomenon known as ‘parabiosis’, but the exact nature (i.e., mutualistic or parasitic) of this interaction
is the subject of debate. We thus attempted to clarify the mutual costs and benefits for each partner (ants and plants) in
the Crematogaster levior/Camponotus femoratus ant-garden parabiosis. The ants’ response to experimental foliar damage to the epiphytes and to the host tree as well as
their behavior and interactions during prey capture were investigated to see if the purported parasitic status of Cr. levior could be demonstrated in either the ant-ant or in the ant-plant interactions. The results show that both species take part
in protecting the epiphytes, refuting the role of Cr. levior as a parasite of the ant-garden mutualism. During capture of large prey Ca. femoratus took advantage from the ability of Cr. levior to discover prey; by following Cr. levior trails Ca. femoratus workers discover the prey in turn and usurp them during agonistic interactions. Nevertheless, the trade-off between the costs
and benefits of this association seems then to be favorable to both species because it is known that Cr. levior benefits from Ca. femoratus building the common carton nests and furnishing protection from vertebrates. Consequently, parabiosis can then be defined
as the only mutualistic association existing between ant species, at least in ant-gardens.
Received 31 August 2006 ; revised 8 December 2006 ; accepted 12 December 2006 相似文献
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Malgorzata Brindell Iwona Stawoska Justyna Supel Andrzej Skoczowski Grazyna Stochel Rudi van Eldik 《Journal of biological inorganic chemistry》2008,13(6):909-918
A systematic study of the reduction of (ImH)[trans-RuCl(4)(dmso)(Im)] (NAMI-A; dmso is dimethyl sulfoxide, Im is imidazole), a promising antimetastasing agent, by L: -ascorbic acid under physiological conditions is reported. Under blood plasma conditions (pH 7.4, 0.1-0.15 M NaCl , 37 degrees C) the rapid reduction of trans-[Ru(III)Cl(4)(dmso)(Im)](-) results in the formation of trans-[Ru(II)Cl(4)(dmso)(Im)](2-) within seconds, and is followed by successive dissociation of the chloride ligands, whereas neither dmso nor imidazole ligands are released during the reaction. Under our experimental conditions, the formation of the ascorbate dianion is the rate-determining step, and once it has formed it reacts rapidly with NAMI-A. Moreover, the NAMI-A complex is very unstable at physiological pH (7.4); therefore, the hydrolysis of NAMI-A cannot be excluded as a competing reaction. During hydrolysis, aquated derivatives via stepwise dissociation of chloride and dmso ligands are formed, and most of these species have a higher redox potential and are expected to be even more easily reduced by ascorbic acid. Thus, it is very likely that the reduced form of NAMI-A or the reduction products of its hydrolytic derivatives react with albumin. The reaction of reduced NAMI-A with human serum albumin leads to the formation of stable adducts, with a binding efficiency very similar to that of the parent complex, viz., 3.2 +/- 0.3 and 4.0 +/- 0.4 mol of Ru(II) and Ru(III) per mole of albumin, respectively, however with a significantly higher reactivity. 相似文献
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A new plant expression vector (pBSbtCry1Ac-GNA) containing two insect resistant genes, a synthetic chimeric gene SbtCry1Ac encoding the insecticidal protein CrylAc and a gene GNA encoding snowdrop lectin (Galanthus nivalis agglutinin) was constructed. Transgenic tobacco plants containing these two genes were obtained through Agrobacterium-mediated transformation of tobacco leaf discs. Results from PCR detection and genomic DNA Southern blot analysis indicated
that both SbtCrylAc gene and GNA gene were integrated into the genome of these plants. Results of Western blot analysis indicated that these two proteins
were expressed in the analyzed plants. Bioassays of Myzus persicae and Helicoverpa assulta on detached leaves of transformed tobacco plants were carried out. The average aphid inhibition rate of these plants tested
at 12 d post-infestation was 71.9 %. The average H. assulta mortality of these plants tested at 6 d post-infestation was up to 89.8 %. The kanamycin resistance of the T1 progeny of these transgenic plants was analyzed and a typical 3:1 segregation was observed. 相似文献