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Physiological Control and Regulation of the Rhodobacter capsulatus cbb Operons 总被引:1,自引:0,他引:1 下载免费PDF全文
George C. Paoli Padungsri Vichivanives F. Robert Tabita 《Journal of bacteriology》1998,180(16):4258-4269
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GTP cyclohydrolase I (GTPCH) is a key enzyme in the de novo synthesis of tetrahydrobiopterin. Previously, the Drosophila melanogaster GTPCH gene has been shown to be expressed from two different promoters (P1 and P2). In our study, the 5′-flanking DNA regions required
for P1 and P2 promoter activities were characterized using transient expression assay. The DNA regions between −98 and +31,
and between −73 and +35 are required for efficient P1 and P2 promoter activities, respectively. The regions between −98 and
−56 and between −73 and −41 may contain critical elements required for the expression of GTPCH in Drosophila. By aligning the nucleotide sequences in the P1 and P2 promoter regions of the Drosophila melanogaster and Drosophila virilis GTPCH genes, several conserved elements including palindromic sequences in the regions critical for P1 and P2 promoter activities
were identified. Western blot analysis of transgenic flies transformed using P1 or P2 promoter-lacZ fusion plasmids further
revealed that P1 promoter expression is restricted to the late pupae and adult developmental stages but that the P2 promoter
driven expression of GTPCH is constitutive throughout fly development. In addition, X-gal staining of the embryos and imaginal discs of transgenic flies
suggests that the P2 promoter is active from stage 13 of embryo and is generally active in most regions of the imaginal discs
at the larval stages. 相似文献
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A phenanthrene-degrading Mycobacterium sp. strain 6PY1 was grown in an aqueous/organic biphasic culture system with phenanthrene as sole carbon source. Its capacity
of degradation was studied during sequential inoculum enrichments, reaching complete phenanthrene degradation at a maximim
rate of 7 mg l−1 h−1. Water–oil emulsions and biofilm formation were observed in biphasic cultures after four successive enrichments. The factors
influencing interfacial area in the emulsions were: the initial phenanthrene concentration, the initial inoculum size, and
the silicone oil volume fraction. The results showed that the interfacial area was mainly dependent on the silicone oil/mineral
salts medium ratio and the inoculum size. 相似文献
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This study was designed to identify rhizobial strains specific to greengram expressing higher tolerance against insecticides,
fipronil and pyriproxyfen, and synthesizing plant growth regulators even amid insecticide-stress. Of the 50 bradyrhizobial
isolates, the Bradyrhizobium sp. strain MRM6 showed tolerance up to 1,600 μg mL−1 against each of fipronil and pyriproxyfen. The tolerant Bradyrhizobium sp. (vigna) produced plant growth promoting substances in substantial amounts, both in the presence and absence of insecticides. The
strain MRM6 was further used to investigate its impact on greengram grown in soils treated with 200 (the recommended dose),
400 and 600 μg kg−1 soil of fipronil and 1,300 (the recommended dose), 2,600 and 3,900 μg kg−1 soil of pyriproxyfen. Fipronil at 600 μg kg−1 soils and pyriproxyfen at 3,900 μg kg−1 soils had greatest toxic effects and decreased plant biomass, symbiotic efficiency, nutrient uptake and seed yield of greengram
plants. The Bradyrhizobium sp. (vigna) inoculant when used with fipronil and pyriproxyfen significantly increased the measured parameters compared to the plants
grown in soils treated solely with the same concentration of each insecticide. This study inferred that the Bradyrhizobium sp. (vigna) strain MRM6 may be exploited as bio-inoculant to increase the productivity of greengram exposed to insecticide-stressed
soils. 相似文献
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Mineralization of diuron has not been previously demonstrated despite the availability of some bacteria to degrade diuron
into 3,4-dichloroaniline (3,4-DCA) and others that can mineralize 3,4-DCA. A bacterial co-culture of Arthrobacter sp. N4 and Delftia acidovorans W34, which respectively degraded diuron (20 mg l−1) to 3,4-DCA and mineralized 3,4-DCA, were able to mineralize diuron. Total diuron mineralization (20 mg l−1) was achieved with free cells in co-culture. When the bacteria were immobilized (either one bacteria or both), the degradation
rate was higher. Best results were obtained with free Arthrobacter sp. N4 cells co-cultivated with immobilized cells of D. acidovorans W34 (mineralization of diuron in 96 h, i.e., 0.21 mg l−1 h−1 vs. 0.06 mg l−1 h−1 with free cells in co-culture). 相似文献
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Changhai Wang Yiyun Wang Qiao Su Xiaorong Gao 《Biotechnology and Bioprocess Engineering》2007,12(2):180-183
A transient expression system for a unicellular marine green alga,Chlorella sp.MACC/C95, was developed using a reporter GUS gene coded for by plasmid pBI121. The results demonstrated a high transformation efficiency
could be achieved by using electroporation to deliver DNA into intact cells and the CaMV35S promoter to drive the foreign
gene expression inChlorella sp.MACC/C95. The use of a carrier DNA coupled with osmosis treatment improved the transformation efficiency, while linearization of the
plasmid had minor effects. Investigation of the effects of DNA concentration and growth phases ofChlorella sp.MACC/C95 on transformation efficiency indicated that the highest level of transient expression was observed when 6 μg mL−1 of plasmid DNA and cells 2–6 days old were used. 相似文献
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Cardoso PG Ribeiro JB Teixeira JA de Queiroz MV de Araújo EF 《Journal of industrial microbiology & biotechnology》2008,35(3):159-166
The pectin lyase (PL) is an industrially important enzyme since it is used for maceration and clarification in the process
of fruit juice production in food industries. In order to increase the yields of pectin lyase we cloned the plg1 (pectin lyase 1) from Penicillium griseoroseum gene under the control of the strong constitutive promoter of the glyceraldehyde-3-phosphate dehydrogenase gene (gpdA) and the terminator region of the tryptophan synthetase (trpC) gene from Aspergillus nidulans (plasmid pAN52-Plg1) and transformed this construct into the P. griseoroseum strain PG63. One of the pAN52-Plg1 multi-copy transformants (strain 105) grown in culture medium containing glucose or sugar
cane juice showed PL activities of 4,804 or 5,202 U ml−1 respectively, which represented 57- and 132-fold increases. In addition, the apparent specific activity of PL produced by
this strain was much higher than the one observed for a commercial pectinase preparation. Evaluation of the extracellular
proteins in the culture supernatant of strain 105 by SDS-PAGE showed the presence of a clear and strong band of approximately
40 kDa that probably corresponds to PL. The enzyme yields reported here demonstrate that the system we developed is able to
express pectin lyase at levels comparable to, or exceeding, previously reported data. 相似文献
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Takada M Nomura N Okada H Nakajima-Kambe T Nakahara T Uchiyama H 《Biotechnology letters》2005,27(12):871-874
Expression of the desulfurization genes (dsz) in Mycobacterium sp. G3 is repressed by sulfate, which is the product of biodesulfurization. An expression clone, pSMTABC, was constructed by placing the dsz genes downstream of the hsp60 promoter and the constructed plasmid was electroporated into G3. The recombinant strain G3-1 desulfurized dibenzothiophene in the presence of 0.5 mM sulfate while the Dsz phenotype was completely repressed in the wild-type strain. However, there was no significant increase in the amount of desulfurization enzymes in G3-1. In addition, G3 had superior separation of diesel oil–water separation activity compared to E. coli, which is superior to desulfurizing rhodococci. 相似文献
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Adjei MD Deck J Heinze TM Freeman JP Williams AJ Sutherland JB 《Journal of industrial microbiology & biotechnology》2007,34(3):219-224
Mycobacterium sp. 7E1B1W and seven other mycobacterial strains known to degrade hydrocarbons were investigated to determine their ability
to metabolize the piperazine ring, a substructure found in many drugs. Cultures were grown at 30°C in tryptic soy broth and
dosed with 3.1 mM N-phenylpiperazine hydrochloride; samples were removed at intervals and extracted with ethyl acetate. Two metabolites were
purified from each of the extracts by high-performance liquid chromatography; they were identified by mass spectrometry and
1H nuclear magnetic resonance spectroscopy as N-(2-anilinoethyl)acetamide and N-acetyl-N′-phenylpiperazine. The results show that mycobacteria have the ability to acetylate piperazine rings and cleave carbon-nitrogen
bonds. 相似文献
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Yoon SH Li C Kim JE Lee SH Yoon JY Choi MS Seo WT Yang JK Kim JY Kim SW 《Biotechnology letters》2005,27(22):1829-1832
E. coli was metabolically engineered to produce vanillin by expression of the fcs and ech genes from Amycolatopsis sp. encoding feruloyl-CoA synthetase and enoyl-CoA hydratase/aldolase, respectively. Vanillin production was optimized by
leaky expression of the genes, under the IPTG-inducible trc promoter, in complex 2YT medium. Supplementation with glucose, fructose, galactose, arabinose or glycerol severely decreased
vanillin production. The highest vanillin production of 1.1 g l−1 was obtained with cultivation for 48 h in 2YT medium with 0.2% (w/v) ferulate, without IPTG and no supplementation of carbon
sources. 相似文献
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Desulfurization of dibenzothiophene by Bacillus subtilis recombinants carrying dszABC and dszD genes
The desulfurization (dsz) genes from Rhodococcus erythropolis DS-3 were successfully integrated into the chromosomes of Bacillus subtilis ATCC 21332 and UV1 using an integration vector pDGSDN, yielding two recombinant strains, B. subtilis M29 and M28 in which the integrated dsz genes were expressed efficiently under the promoter, Pspac. The dibenzothiophene (DBT) desulfurization efficiency of M29 was 16.2 mg DBT l−1 h−1 at 36 h, significantly higher than that of R. erythropolis DS−3 and B. subtilis M28 and also showed no product inhibition. The interfacial tension of the supernatant fermented by M29 varied from 48 mN m−1 to 4.2 mN m−1, lower than that of the recombinant strain, M28, reveals that the biosurfactant secreted from M29 may have an important function in the DBT desulfurization process. 相似文献
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George C. Paoli Nancy Strom Morgan F. R. Tabita Jessup M. Shively 《Archives of microbiology》1995,164(6):396-405
Rhodobacter capsulatus fixes CO2 via the Calvin reductive pentose phosphate pathway and, like some other nonsulfur purple bacteria, is known to synthesize
two distinct structural forms of ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO). Cosmid clones that hybridized
to form I (cbbLcbbS) and form II (cbbM) RubisCO gene probes were isolated from a genomic library of R. capsulatus strain SB1003. Southern blotting and hybridization analysis with gene-specific probes derived from Rhodobacter sphaeroides revealed that R. capsulatus cbbM is clustered with genes encoding other enzymes of the Calvin cycle, including fructose 1,6/sedoheptulose 1,7-bisphosphatase
(cbbF), phosphoribulokinase (cbbP), transketolase (cbbT), glyceraldehyde-3-phosphate dehydrogenase (cbbG), and fructose 1,6-bisphosphate aldolase (cbbA), as well as a gene (cbbR) encoding a divergently transcribed LysR-type regulatory protein. Surprisingly, a cosmid clone containing the R. capsulatus form I RubisCO genes (cbbL and cbbS) failed to hybridize to the other cbb structural gene probes, unlike the situation with the closely related organism R. sphaeroides. The form I and form II RubisCO genes were cloned into pUC-derived vectors and were expressed in Escherichia coli to yield active recombinant enzyme in each case. Complementation of a RubisCO-deletion strain of R. sphaeroides to photosynthetic growth by R. capsulatus cbbLcbbS or cbbM was achieved using the broad host-range vector, pRK415, and R. sphaeroides expression vector pRPS-1.
Received: 6 June 1995 / Accepted: 29 September 1995 相似文献
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Schwedock J Harmer TL Scott KM Hektor HJ Seitz AP Fontana MC Distel DL Cavanaugh CM 《Archives of microbiology》2004,182(1):18-29
Chemoautotrophic endosymbionts residing in Solemya velum gills provide this shallow water clam with most of its nutritional requirements. The cbb gene cluster of the S. velum symbiont, including cbbL and cbbS, which encode the large and small subunits of the carbon-fixing enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO), was cloned and expressed in Escherichia coli. The recombinant RubisCO had a high specific activity, 3 mol min–1 mg protein –1, and a K
CO2 of 40.3 M. Based on sequence identity and phylogenetic analyses, these genes encode a form IA RubisCO, both subunits of which are closely related to those of the symbiont of the deep-sea hydrothermal vent gastropod Alviniconcha hessleri and the photosynthetic bacterium Allochromatium vinosum. In the cbb gene cluster of the S. velum symbiont, the cbbLS genes were followed by cbbQ and cbbO, which are found in some but not all cbb gene clusters and whose products are implicated in enhancing RubisCO activity post-translationally. cbbQ shares sequence similarity with nirQ and norQ, found in denitrification clusters of Pseudomonas stutzeri and Paracoccus denitrificans. The 3 region of cbbO from the S. velum symbiont, like that of the three other known cbbO genes, shares similarity to the 3 region of norD in the denitrification cluster. This is the first study to explore the cbb gene structure for a chemoautotrophic endosymbiont, which is critical both as an initial step in evaluating cbb operon structure in chemoautotrophic endosymbionts and in understanding the patterns and forces governing RubisCO evolution and physiology. 相似文献
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Population Dynamics of Two Toluene Degrading Bacterial Species in a Contaminated Stream 总被引:4,自引:0,他引:4
Toluene uptake by a benthic biofilm community was previously shown to vary seasonally from 0.03 m hr−1 in winter to 0.2 m hr−1 in summer in a solvent-contaminated stream of the Aberjona watershed. We used quantitative PCR to estimate the population
dynamics of previously isolated species of toluene-degrading Xanthobacter autotrophicus and Mycobacterium sp. in both toluene-contaminated and uncontaminated reaches of the stream, and to estimate their relative roles in overall
biodegradation rate. Quantification using specific 16S rDNA primers for X. autotrophicus and Mycobacterium sp. showed that populations of both species were much larger in the toluene-contaminated than the toluene-free reach, in
agreement with earlier culture-based investigations. A relatively brief bloom of X. autotrophicus occurred in the contaminated reach in the summer, while Mycobacterium sp. populations occurred at elevated densities for more than 5 months. Calculations showed that Mycobacterium, previously thought to be less important than Xanthobacter in annual toluene degradation based on single time-point CFU estimates, appears actually more important because of this longer
persistence. 相似文献
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Abdelhay A Magnin JP Gondrexon N Baup S Willison J 《Applied microbiology and biotechnology》2008,79(5):881-888
In the present paper, the degradation of phenanthrene, a model polycyclic aromatic hydrocarbon compound, by the Mycobacterium strain 6PY1 was optimized in a biphasic culture medium. The optimization and modeling were performed using the design of
experiments methodology. The temperature, the silicone oil/mineral salts medium volume ratio, and the initial cell concentration,
were used as the central composite design parameters. In all experiments, the phenanthrene was degraded to undetectable levels.
Response surface methodology was successfully employed to derive an empirical model describing the rate and time of degradation
and to deduce the optimal degradation conditions. As a result of the optimization processes, the optimal responses for the
degradation rate, the volumetric degradation rate, and the 90% degradation time were estimated to be 0.172 mg h−1, 22 mg l−1 h−1, and 18 h, respectively. 相似文献
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Andreazza R Okeke BC Pieniz S Brandelli A Lambais MR Camargo FA 《Biological trace element research》2011,143(2):1182-1192
Environmental copper contamination is a serious human health problem. Copper reductase is produced by microorganisms to facilitate
copper uptake by ATPases into the cells increasing copper biosorption. This study assessed the reduction of Cu(II) by cell-free
extracts of a highly copper-resistant bacterium, Pseudomonas sp. strain NA, isolated from vineyard soil contaminated with copper. Both intact cells and cell-free extract of Pseudomonas sp. strain NA displayed substantial reduction of Cu(II). Intact cells reduced more then 80 mg L−1 of Cu(II) from medium amended with 200 mg L−1 of copper after 24 h of incubation. Cell-free extract of the isolate reduced more than 65% of the Cu(II) at initial copper
concentration of 200 mg L−1 after 24 h. Soluble protein production was high at 72 h of incubation at 100 mg L−1 of copper, with more then 60 μg L−1 of total soluble protein in cell-free extract recorded. Cu(II) reduction by isolate NA was increased when copper concentration
increased for both intact cells and cell-free extract. Results indicate that Pseudomonas sp. strain NA produces copper reductase enzyme as the key mechanism of copper biotransformation. 相似文献