共查询到20条相似文献,搜索用时 31 毫秒
1.
V. N. Verbenko L. V. Kuznetsova E. P. Krupyan V. I. Shalguev 《Russian Journal of Genetics》2009,45(10):1192-1199
Plasmids pKS5 and pKSrec30 carrying normal and mutant alleles of the Deinococcus recA gene controlled by the lactose promoter slightly increase radioresistance of Escherichia coli cells with mutations in genes recA and ssb. The RecA protein of D. radiodurans is expressed in E. coli cells, and its synthesis can be supplementary induced. The radioprotective effect of the xenologic protein does not exceed
1.5 fold and yields essentially to the contribution of plasmid pUC19-recA1.1 harboring the E. coli recA
+ gene in the recovery of resistance of the ΔrecA deletion mutant. These data suggest that the expression of D. radiodurans recA gene in E. coli cells does not complement mutations at gene recA in the chromosome possibly due to structural and functional peculiarities of the D. radiodurans RecA protein. 相似文献
2.
In Shigella and enteroinvasive Escherichia coli (EIEC), the etiologic agents of shigellosis in humans, the determinants responsible for entry of bacteria into and dissemination within epithelial cells are encoded by a virulence plasmid. To understand the evolution of the association between the virulence plasmid and the chromosome, we performed a phylogenetic analysis using the sequences of four chromosomal genes (trpA, trpB, pabB, and putP) and three virulence plasmid genes (ipaB, ipaD, and icsA) of a collection of 51 Shigella and EIEC strains. The phylogenetic tree derived from chromosomal genes showed a typical star phylogeny, indicating a fast diversification of Shigella and EIEC groups. Phylogenetic groups obtained from the chromosomal and plasmidic genes were similar, suggesting that the virulence plasmid and the chromosome share similar evolutionary histories. The few incongruences between the trees could be attributed to exchanges of fragments of different plasmids and not to the transfer of an entire plasmid. This indicates that the virulence plasmid was not transferred between the different Shigella and EIEC groups. These data support a model of evolution in which the acquisition of the virulence plasmid in an ancestral E. coli strain preceded the diversification by radiation of all Shigella and EIEC groups, which led to highly diversified but highly specialized pathogenic groups. 相似文献
3.
4.
Huan-Mei Li Lian-Tai Yan Cai-Fang Sun Jin-Jin Yuan-Gao Qing Hong Li Shun-Peng 《World journal of microbiology & biotechnology》2011,27(6):1323-1329
A bacterial strain K9 capable of degrading malachite green was isolated from the sludge of the wastewater treatment system
of a chemical plant. It was identified preliminarily as Pseudomonas sp. Strain K9 was also able to degrade other triphenylmethane dyes, such as Crystal Violet and Basic Fuchsin. The gene tmr2, encoding the triphenylmethane reductase, was cloned from strain K9, and functionally expressed in E. coli. A 5946-bp DNA fragment including the tmr2 gene was cloned from the genomic DNA of strain K9 by chromosome walking. Its sequence analysis showed that tmr2 was associated with a typical mobile element ISPpu12 consisting of tnpA (encoding a transposase), lspA (encoding a lipoprotein signal peptidase) and orf1 (encoding a putative MerR family regulator), orf2 (encoding a CDF family heavy metal/H+ antiporter). This association was also found in another malachite green-degrading strain Pseudomonas sp. MDB-1, which indicated that the tmr2 gene might be a horizontally transferable gene. 相似文献
5.
Background
The Brucella genome contains an insertion sequence (IS) element called IS711 or IS6501, which is specific to the genus. The copy number of IS711 varies in the genome of the different Brucella species, ranging from 7 in B. abortus, B. melitensis and B. suis to more than 30 in B. ovis and in Brucella strains isolated from marine mammals. At present, there is no experimental evidence of transposition of IS711, but the occurrence of this element with a high copy number in some species, and the isolation of Brucella strains with "ectopic" copies of IS711 suggested that this IS could still transpose. 相似文献6.
It was shown that IS element ISPpyl isolated earlier in the permafrost strain Psychrobacter maritimus MR29-12 has a high level of functional activity in cells of the heterologous host Escherichia coli K-12. ISPpyl can be translocated in E. coli cells by itself and mobilize adjacent genes and can also form composite transposons flanked by two copies of this element. Apart from translocations between different plasmids, the composite ISPpyl-containing transposon Tn5080a is capable of translocation from the plasmid into the E. coli chromosome with high frequency and from the chromosome into the plasmid. Among products of Tn5080a transposition into plasmid R388, simple insertions were predominantly formed together with cointegrates. Upon mobilization of adjacent genes with the use of one ISPpyl copy, only cointegrates arise. 相似文献
7.
Farzana Ashrafi Neela L. Nonaka M. H. Rahman S. Suzuki 《World journal of microbiology & biotechnology》2009,25(6):1095-1101
The transferability of the tetracycline (TC) resistance gene tet(M) from marine bacteria to human enteric bacteria was examined by a filter-mating method. Vibrio spp., Lactococcus garvieae, Bacillus spp., Lactobacillus sp., and Paenibacillus sp. were used as donors, and Escherichia coli JM109 and Enterococcus faecalis JH2-2 were used as recipients. The combination of Vibrio spp. and E. coli resulted in 5/68 positive transconjugants with a transfer rate of 10−7 to 10−3; however, no transfer was observed with E. faecalis. In case of L. garvieae and E. faecalis, 6/6 positive transconjugants were obtained with a transfer rate of 10−6 to 10−5; however, no transfer was observed with E. coli. The tet(M) gene of Bacillus, Lactobacillus, and Paenibacillus were not transferred to either E. coli or E. faecalis. tet(M) transfer was confirmed in positive E. coli and E. faecalis transconjugants by polymerase chain reaction (PCR) and Southern hybridization. All the donor strains did not harbor plasmids,
while they all harbored transposon Tn916. In the transconjugants, the transposon was not detected by PCR, suggesting the possible transfer of tet(M) from the marine bacterial chromosome to the recipient chromosome. This is the first report to show that tet(M) can be transferred from marine bacteria to human enteric bacteria in a species-specific manner. 相似文献
8.
Albermann C 《Biotechnology letters》2011,33(2):313-319
The heterologous synthesis of lycopene in non-carotenogenic Escherichia coli required the introduction of the biosynthesis genes crtE, crtB, and crtI. Recombinant E. coli strains, expressing each lycopene biosynthesis gene from Pantoea ananatis using multi-copy plasmid or single-copies after stable chromosomal integration, were cultivated and the formation of lycopene
was investigated. The different expression conditions significantly influenced the lycopene formation as well as the growth
behaviour. High plasmid expression levels of crtI with a single copy background of crtE and crtB in E. coli led to a predominate synthesis of tetradehydrolycopene at 253 μg g−1 (cdw). 相似文献
9.
Lee YK Yoon BD Yoon JH Lee SG Song JJ Kim JG Oh HM Kim HS 《Applied microbiology and biotechnology》2007,75(3):567-572
The srfA operon is required for the nonribosomal biosynthesis of the cyclic lipopeptide, surfactin. The srfA operon is composed of the four genes, srfAA, srfAB, srfAC, and srfAD, encoding the surfactin synthetase subunits, plus the sfp gene that encodes phosphopantetheinyl transferase. In the present study, 32 kb of the srfA operon was amplified from Bacillus subtilis C9 using a long and accurate PCR (LA-PCR), and ligated into a pIndigoBAC536 vector. The ligated plasmid was then transformed
into Escherichia coli DH10B. The transformant ET2 showed positive signals to all the probes for each open reading frame (ORF) region of the srfA operon in southern hybridization, and a reduced surface tension in a culture broth. Even though the surface-active compound
extracted from the E. coli transformant exhibited a different R
f value of 0.52 from B. subtilis C9 or authentic surfactin (R
f = 0.63) in a thin layer chromatography (TLC) analysis, the transformant exhibited a much higher surface-tension-reducing
activity than the wild-type strain E. coli DH10B. Thus, it would appear that an intermediate metabolite of surfactin was expressed in the E. coli transformant harboring the srfA operon. 相似文献
10.
Sundin GW 《Current microbiology》2002,45(1):63-69
We report the linkage of the strA-strB streptomycin-resistance genes with Class 1 integron sequences on pSTR1, a 75-kb multiple antibiotic-resistance plasmid from
Shigella flexneri. strA-strB had previously been detected only within Tn5393, a Tn3-family transposon, and on small nonconjugative broad-host-range plasmids such as RSF1010. The geographic range of Tn5393 was also extended to Pseudomonas spp. isolated from apple trees in New Zealand and soil in the USA. Comparative sequence analyses indicated that strA-strB from Tn5393 and nonconjugative plasmids constitute distinct recent lineages with strA-strB from pSTR1 intermediate between the other two. The carriage of strA-strB within an integron, a transposon, and on broad-host-range plasmids has facilitated the world-wide dissemination of this determinant
among at least 21 bacterial genera.
Received: 8 August 2001 / Accepted: 26 November 2001 相似文献
11.
Background
Alpha (α)-hemolysin is a pore forming cytolysin and serves as a virulence factor in intestinal and extraintestinal pathogenic strains of E. coli. It was suggested that the genes encoding α-hemolysin (hlyCABD) which can be found on the chromosome and plasmid, were acquired through horizontal gene transfer. Plasmid-encoded α-hly is associated with certain enterotoxigenic (ETEC), shigatoxigenic (STEC) and enteropathogenic E. coli (EPEC) strains. In uropathogenic E. coli (UPEC), the α-hly genes are located on chromosomal pathogenicity islands. Previous work suggested that plasmid and chromosomally encoded α-hly may have evolved independently. This was explored in our study. 相似文献12.
13.
Joong-Chul Lee Jeong-Heon Cha Dennis B. Zerbv George C. Stewart 《Current microbiology》2003,47(2):0146-0152
The divIVB operon of Bacillus subtilis includes the cell shape-associated mre genes, including the membrane-associated proteins MreC and MreD. TnphoA mutagenesis was utilized to analyze a topological model for MreC. MreC has a short cytoplasmic amino terminus, a single membrane-spanning domain, and a large carboxy terminal domain which lies externally to the outer leaflet of the cell membrane. Expression of the B. subtilis MreB protein, or the Mre C and D proteins, results in a morphological conversion of the Escherichia coli host cells from a rod to a roughly spherical cell, morphologically similar to mre-negative mutants of E. coli. Immunolocalization of the MreC protein in B. subtilis revealed that this protein is found at the midcell division site of the bacterial cells, consistent with the postulated role of the Mre proteins in the regulation of septum-specific peptidoglycan synthesis. RID= ID= <E5>Correspondence to: </E5>G.C. Stewart; <E5>email:</E5> stewart@vet.ksu.edu Received: 5 August 2002 / Accepted: 7 October 2002 相似文献
14.
Brzuszkiewicz E Thürmer A Schuldes J Leimbach A Liesegang H Meyer FD Boelter J Petersen H Gottschalk G Daniel R 《Archives of microbiology》2011,193(12):883-891
The genome sequences of two Escherichia coli O104:H4 strains derived from two different patients of the 2011 German E. coli outbreak were determined. The two analyzed strains were designated E. coli GOS1 and GOS2 (German outbreak strain). Both isolates comprise one chromosome of approximately 5.31 Mbp and two putative plasmids. Comparisons of the 5,217
(GOS1) and 5,224 (GOS2) predicted protein-encoding genes with various E. coli strains, and a multilocus sequence typing analysis revealed that the isolates were most similar to the entero-aggregative
E. coli (EAEC) strain 55989. In addition, one of the putative plasmids of the outbreak strain is similar to pAA-type plasmids of
EAEC strains, which contain aggregative adhesion fimbrial operons. The second putative plasmid harbors genes for extended-spectrum
β-lactamases. This type of plasmid is widely distributed in pathogenic E. coli strains. A significant difference of the E. coli GOS1 and GOS2 genomes to those of EAEC strains is the presence of a prophage encoding the Shiga toxin, which is characteristic
for enterohemorrhagic E. coli (EHEC) strains. The unique combination of genomic features of the German outbreak strain, containing characteristics from
pathotypes EAEC and EHEC, suggested that it represents a new pathotype Entero-Aggregative-Haemorrhagic E
scherichia
c
oli (EAHEC). 相似文献
15.
16.
Makoto Urata Jun Tsuchimoto Kinya Yasui Masaaki Yamaguchi 《Development genes and evolution》2009,219(7):377-382
Deuterostomes comprise a monophyletic group of animals that include chordates, xenoturbellids, and the Ambulacraria, which
consists of echinoderms and hemichordates. The ancestral chordate probably had 14 Hox genes aligned linearly along the chromosome, with the posterior six genes showing an independent duplication compared to
protostomes. In contrast, ambulacrarians are characterized by a duplication of the posterior Hox genes, resulting in three genes known as Hox11/13a, Hox11/13b, and Hox11/13c. Here, we isolated 12 Hox genes from the hemichordate Balanoglossus misakiensis and found an extra Hox gene that has not been reported in hemichordates. The extra B. misakiensis gene was suggested to be Hox8 from paralog-characteristic residues in its hexapepetide motif and homeodomain and a comparison with Strongylocentrotus purpuratus Hox genes. Our data suggest that the ancestor of echinoderms and hemichordates may have had a full complement of 12 Hox genes. 相似文献
17.
Kateryna Zelena Holger Zorn Manfred Nimtz Ralf Günter Berger 《Archives of microbiology》2009,191(5):397-402
For the heterologous expression of the msp2 gene from the edible mushroom Marasmius scorodonius in Escherichia coli the cDNA encoding the extracellular Msp2 peroxidase was cloned into the pBAD III expression plasmid. Expression of the protein
with or without signal peptide was investigated in E. coli strains TOP10 and LMG194. Different PCR products were amplified for expression of the native target protein or a protein
with a signal peptide. Omitting the native stop codon and adding six His-residues resulted in a fusion protein amenable to
immune detection and purification by immobilised metal affinity chromatography. In E. coli the recombinant protein was produced in high yield as insoluble inclusion bodies. The influence of different parameters on
MsP2 refolding was investigated. Active enzyme was obtained by glutathione-mediated oxidation in a medium containing urea,
Ca2+, and hemin. 相似文献
18.
Soo Jin Lee Eun Kyoung Oh Young Hoon Oh Jong In Won Sung Ok Han Jin Won Lee 《Biotechnology and Bioprocess Engineering》2010,15(5):770-776
Ethanol is generally toxic to microorganisms, and intracellular and extracellular accumulation of ethanol inhibits cell growth
and metabolism. In this study, pyruvate decarboxylase (pdc) and alcohol dehydrogenase (adhB) were cloned into pET-32a vector
and then introduced into E. coli BL21 to produce ethanol. Heat shock genes (BEM1 and SOD2) from Saccharomyces cerevisiae were inserted into recombinant ethanolic E. coli using pET28_a vector to improve ethanol shock resistance. Three different strains were constructed: Ethanolic E. coli (adhB and pdc genes inserted using pET32_a vector), BEM1 gene-inserted E. coli (BEM1 inserted using pET_28a), and SOD2-inserted E. coli (SOD2 inserted using pET28_a). Construction of these three different strains allowed comparison of the functions of these
heat shock genes as well as their roles in ethanol tolerance. The toxicity of ethanol in recombinant ethanolic E. coli was tested by measuring cell growth in response to various ethanol concentrations. The results show that SOD2-inserted E. coli showed higher ethanol resistance than ethanolic E. coli. 相似文献
19.
Yoon SH Kim JE Lee SH Park HM Choi MS Kim JY Lee SH Shin YC Keasling JD Kim SW 《Applied microbiology and biotechnology》2007,74(1):131-139
The lycopene synthetic pathway was engineered in Escherichia coli using the carotenoid genes (crtE, crtB, and crtI) of Pantoea agglomerans and Pantoea ananatis. E. coli harboring the P. agglomerans crt genes produced 27 mg/l of lycopene in 2YT medium without isopropyl-beta-d-thiogalactopyranoside (IPTG) induction, which was twofold higher than that produced by E. coli harboring the P. ananatis crt genes (12 mg/l lycopene) with 0.1 mM IPTG induction. The crt genes of P. agglomerans proved better for lycopene production in E. coli than those of P. ananatis. The crt genes of the two bacteria were also compared in E. coli harboring the mevalonate bottom pathway, which was capable of providing sufficient carotenoid building blocks, isopentenyl
diphosphate (IPP) and dimethylallyl diphosphate (DMAPP), with exogenous mevalonate supplementation. Lycopene production significantly
increased using the mevalonate bottom pathway and 60 mg/l of lycopene was obtained with the P. agglomerans crt genes, which was higher than that obtained with the P. ananatis crt genes (35 mg/l lycopene). When crtE among the P. ananatis crt genes was replaced with P. agglomerans crtE or Archaeoglobus fulgidus gps, both lycopene production and cell growth were similar to that obtained with P. agglomerans
crt genes. The crtE gene was responsible for the observed difference in lycopene production and cell growth between E. coli harboring the crt genes of P. agglomerans and P. ananatis. As there was no significant difference in lycopene production between E. coli harboring P. agglomerans
crtE and A. fulgidus gps, farnesyl diphosphate (FPP) synthesis was not rate-limiting in E. coli.
Sang-Hwal Yoon and Ju-Eun Kim: These authors contributed equally to this work. 相似文献
20.
R. A. Komakhin V. V. Komakhina N. A. Milyukova A. A. Zhuchenko 《Russian Journal of Genetics》2012,48(1):23-31
To study and induce meiotic recombination in plants, we generated and analyzed transgenic tomato hybrids F1-RecA and F1-NLS-recA-LicBM3 expressing, respectively, the recA gene of Escherichia coli and the NLS-recA-licBM3 gene. It was found that the recA and NLS-recA-licBM3 genes are inherited through the maternal and paternal lineages, they have no selective influence on the pollen and are contained
in tomato F1-RecA and F1-NLS-RecA-LicBM3 hybrids outside the second chromosome in the hemizygous state. The comparative analysis of the meiotic recombination
frequency (rf) in the progenies of the transgenic and nontransgenic hybrids showed that only the expression of the recA gene of E. coli in cells of the F1-RecA plants produced a 1.2–1.5-fold increase in the frequency of recombination between some linked marker
genes of the second chromosome of tomato. 相似文献