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1.
Biotechnol Prog ; 32(4): 1017-28, 2016 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-27037961

RESUMO

This study investigates synthesis of poly(3-hydroxybutyrate)/diethylene glycol copolymers (P3HB/DEG) by Cupriavidus eutrophus B-10646 cells as related to DEG concentration in the medium and the time when it is added to the culture of cells synthesizing P3HB. The study determines the limits of physiological effect of DEG on C. eutrophus cells, showing that at DEG concentrations above 30 g/L, it inhibits cell growth, decreasing cell concentration and total P3HB/DEG yield and inducing an increase in the degree of saturation of fatty acids in lipids of cell cytoplasmic membrane. A series of copolymers containing different molar fractions of DEG (between 0.13 and 3.0 mol%) have been synthesized and their physicochemical, physical/mechanical, and biological properties have been investigated as related to the chemical composition and proportions of DEG monomers of the polymers. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1017-1028, 2016.


Assuntos
Cupriavidus/metabolismo , Etilenoglicóis/metabolismo , Hidroxibutiratos/metabolismo , Poliésteres/metabolismo , Animais , Proliferação de Células , Sobrevivência Celular , Células Cultivadas , Físico-Química , Cupriavidus/citologia , Cupriavidus/crescimento & desenvolvimento , Etilenoglicóis/química , Hidroxibutiratos/química , Camundongos , Células NIH 3T3 , Poliésteres/química
2.
FEMS Microbiol Lett ; 353(1): 32-9, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24822276

RESUMO

Cupriavidus metallidurans CH34 has long been known for its temperature-induced mutagenesis and mortality phenotype (TIMM), for which a genetic origin has been suggested repeatedly. In this report, we present microscopic-based evidences that the TIMM process actually starts with a septation defect, leading to aberrant cell morphologies. Moreover, the septation defect of CH34 could be induced by NaOCl, thus showing that the TIMM phenotype may be part of a more general stress response. Sequence analysis of a TIMM survivor exhibiting a recurrent recognizable lysA mutation ruled out the possibility of a genetic ground linking TIMM survival and peptidoglycan synthesis.


Assuntos
Divisão Celular/efeitos dos fármacos , Cupriavidus/citologia , Cupriavidus/efeitos dos fármacos , Hipoclorito de Sódio/farmacologia , Temperatura , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Carboxiliases/genética , Carboxiliases/metabolismo , Cupriavidus/genética
3.
Metallomics ; 6(3): 421-36, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24407051

RESUMO

Cupriavidus metallidurans strain CH34 accomplishes a high level of transition metal resistance by a combination of rather unspecific transition metal import and controlled efflux of surplus metals. Using the plasmid-free mutant strain AE104 that possesses only a limited number of metal efflux systems, cellular metal pools were identified as counterparts of these transport reactions. At low zinc concentrations strain AE104 took up Zn(II) until the zinc content reached an optimum level of 70,000 Zn(II) per cell in the exponential phase of growth, whereas a ΔzupT mutant lacking the zinc importer ZupT contained only 20,000 Zn(II)/cell, possibly the minimum zinc content. Mutant and parent cells accumulated up to 125,000 Zn(II) per cell at high (100 µM) external zinc concentrations (optimum zinc content). When the mutant strain Δe4, which has all the known genes for zinc efflux systems deleted, was cultivated in the presence of zinc concentrations close to its upper tolerance level (10 µM), these cells contained 250,000 Zn(II) per cell, probably the maximum zinc content. Instead of zinc, 120,000 cobalt or cadmium ions could also fill-up parts of this zinc pool, showing that it is in fact an undefined pool of divalent transition metal cations bound with low substrate specificity. Even when the cells contained sufficient numbers of total zinc, the zinc importer ZupT was required for important cellular processes, indicating the presence of a pool of tightly bound zinc ions, which depends on ZupT for efficient replenishment. The absence of ZupT led to the formation of inclusion bodies, perturbed oxidative stress resistance and decreased efficiency in the synthesis of the zinc-dependent subunit RpoC of the RNA polymerase, leading to RpoC accumulation. Moreover, when a czc allele for a zinc-exporting transenvelope efflux system CzcCBA was constitutively expressed in a ΔzupT mutant, this led to the disappearance of the CzcA protein and the central subunit of the protein complex, and to the loss of metal resistance. This phenomenon occurred only if the ΔzupT cells had been cultivated for several transfers in solid culture medium, which generated severe zinc starvation. Thus, two zinc pools appear to exist in C. metallidurans: one pool of at least 20,000 tightly bound Zn(II) ions, in addition to a second pool of up to 200,000 cations bound loosely and with low substrate specificity.


Assuntos
Proteínas de Bactérias/genética , Proteínas de Transporte/genética , Cupriavidus/genética , Cupriavidus/metabolismo , Deleção de Genes , Zinco/metabolismo , Proteínas de Bactérias/metabolismo , Cádmio/metabolismo , Proteínas de Transporte/metabolismo , Cobalto/metabolismo , Cupriavidus/citologia , RNA Polimerases Dirigidas por DNA/metabolismo , Regulação Bacteriana da Expressão Gênica , Estresse Oxidativo
4.
J Basic Microbiol ; 54(4): 306-14, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23564035

RESUMO

Cupriavidus metallidurans CH34 and Pseudomonas putida mt2 were used as cadmium (Cd) resistant and sensitive bacteria, respectively to study the effect of Cd on physicochemical surface properties which include the study of surface charge and hydrophobicity which are subjected to vary under stress conditions. In this research work, effective concentration 50 (EC50 ) was calculated to exclude the doubt that dead cells were also responding and used as reference point to study the changes in cell surface properties in the presence of Cd. EC50 of C. metallidurans CH34 was found to be 2.5 and 0.25 mM for P. putida mt2. The zeta potential analysis showed that CH34 cells were slightly less unstable than mt2 cells as CH34 cells exhibited -8.5 mV more negative potential than mt2 cells in the presence of Cd in growth medium. Cd made P. putida mt2 surface to behave as intermediate hydrophilic (θw = 25.32°) while C. metallidurans CH34 as hydrophobic (θw = 57.26°) at their respective EC50 . Although belonging to the same gram-negative group, both bacteria behaved differently in terms of changes in membrane fluidity. Expression of trans fatty acids was observed in mt2 strain (0.45%) but not in CH34 strain (0%). Similarly, cyclopropane fatty acids were observed more in mt2 strain (0.06-0.14%) but less in CH34 strain (0.01-0.02%). Degree of saturation of fatty acids decreased in P. putida mt2 (36.8-33.75%) while increased in C. metallidurans CH34 (35.6-39.3%). Homeoviscous adaptation is a survival strategy in harsh environments which includes expression of trans fatty acids and cyclo fatty acids in addition to altered degree of saturation. Different bacteria show different approaches to homeoviscous adaptation.


Assuntos
Cádmio/farmacologia , Cupriavidus/efeitos dos fármacos , Pseudomonas putida/efeitos dos fármacos , Físico-Química , Cupriavidus/química , Cupriavidus/citologia , Ácidos Graxos/química , Interações Hidrofóbicas e Hidrofílicas , Fluidez de Membrana , Fosfolipídeos/química , Pseudomonas putida/química , Pseudomonas putida/citologia , Estereoisomerismo , Estresse Fisiológico , Propriedades de Superfície
5.
Appl Environ Microbiol ; 77(6): 2161-4, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21257807

RESUMO

The beta-rhizobium Cupriavidus taiwanensis forms indeterminate nodules on Mimosa pudica. C. taiwanensis bacteroids resemble free-living bacteria in terms of genomic DNA content, cell size, membrane permeability, and viability, in contrast to bacteroids in indeterminate nodules of the galegoid clade. Bacteroid differentiation is thus unrelated to nodule ontogeny.


Assuntos
Cupriavidus/citologia , Mimosa/microbiologia , Nódulos Radiculares de Plantas/microbiologia
6.
Proc Natl Acad Sci U S A ; 107(11): 4919-24, 2010 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-20194784

RESUMO

The toxic fermentation inhibitors in lignocellulosic hydrolysates pose significant problems for the production of second-generation biofuels and biochemicals. Among these inhibitors, 5-(hydroxymethyl)furfural (HMF) and furfural are specifically notorious. In this study, we describe the complete molecular identification and characterization of the pathway by which Cupriavidus basilensis HMF14 metabolizes HMF and furfural. The identification of this pathway enabled the construction of an HMF and furfural-metabolizing Pseudomonas putida. The genetic information obtained furthermore enabled us to predict the HMF and furfural degrading capabilities of sequenced bacterial species that had not previously been connected to furanic aldehyde metabolism. These results pave the way for in situ detoxification of lignocellulosic hydrolysates, which is a major step toward improved efficiency of utilization of lignocellulosic feedstock.


Assuntos
Cupriavidus/metabolismo , Furaldeído/análogos & derivados , Redes e Vias Metabólicas , Cupriavidus/citologia , Cupriavidus/genética , Cupriavidus/crescimento & desenvolvimento , Elementos de DNA Transponíveis/genética , Furaldeído/metabolismo , Genes Bacterianos/genética , Mutagênese/genética , Oxirredutases/metabolismo , Fenótipo , Pseudomonas putida/metabolismo
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