cloning and characterization of the pseudomonas aeruginosa zwf gene encoding glucose-6-phosphate dehydrogenase, an enzyme important in resistance to methyl viologen (paraquat).in this study, we cloned the pseudomonas aeruginosa zwf gene, encoding glucose-6-phosphate dehydrogenase (g6pdh), an enzyme that catalyzes the nad+- or nadp+-dependent conversion of glucose-6-phosphate to 6-phosphogluconate. the predicted zwf gene product is 490 residues, which could form a tetramer with a molecular mass of approximately 220 kda. g6pdh activity and zwf transcription were maximal in early logarithmic phase when inducing substrates such as glycerol, glucose, or gluconate were abun ...19989537370
molecular analysis of the gene encoding f420-dependent glucose-6-phosphate dehydrogenase from mycobacterium smegmatis.the gene fgd, which codes for f420-dependent glucose-6-phosphate dehydrogenase (fgd), was cloned from mycobacterium smegmatis, and its sequence was determined and analyzed. a homolog of fgd which has a very high similarity to the m. smegmatis fgd-derived amino acid sequence was identified in mycobacterium tuberculosis. fgd showed significant homology with f420-dependent n5,n10-methylene-tetrahydromethanopterin reductase (mer) from methanogenic archaea and with several hypothetical proteins from ...19989555906
design and evaluation of pcr primers for analysis of bacterial populations in wine by denaturing gradient gel electrophoresis.denaturing gradient gel electrophoresis (dgge) of pcr-amplified ribosomal dna (rdna) is routinely used to compare levels of diversity of microbial communities and to monitor population dynamics. while using pcr-dgge to examine the bacteria in wine fermentations, we noted that several commonly used pcr primers for amplifying bacterial 16s rdna also coamplified yeast, fungal, or plant dna present in samples. unfortunately, amplification of nonbacterial dna can result in a masking of bacterial popu ...200314602643
real-time quantitative pcr (qpcr) and reverse transcription-qpcr for detection and enumeration of total yeasts in wine.real-time pcr, or quantitative pcr (qpcr), has been developed to rapidly detect and quantify the total number of yeasts in wine without culturing. universal yeast primers were designed from the variable d1/d2 domains of the 26s rrna gene. these primers showed good specificity with all the wine yeasts tested, and they did not amplify the most representative wine species of acetic acid bacteria and lactic acid bacteria. numerous standard curves were constructed with different strains and species g ...200617088381
magnetospirillum bellicus sp. nov., a novel dissimilatory perchlorate-reducing alphaproteobacterium isolated from a bioelectrical reactor.previously isolated dissimilatory perchlorate-reducing bacteria (dprb) have been primarily affiliated with the betaproteobacteria. enrichments from the cathodic chamber of a bioelectrical reactor (ber) inoculated from creek water in berkeley, ca, yielded a novel organism most closely related to a previously described strain, wd (99% 16s rrna gene identity). strain vdy(t) has 96% 16s rrna gene identity to both magnetospirillum gryphiswaldense and magnetospirillum magnetotacticum, and along with s ...201020495050
genome sequence of a cellulose-producing bacterium, gluconacetobacter hansenii atcc 23769.the gram-negative bacterium gluconacetobacter hansenii is considered a model organism for studying cellulose synthesis. we have determined the genome sequence of strain atcc 23769.201020543071
continuous control of the flow in biochemical pathways through 5' untranslated region sequence modifications in mrna expressed from the broad-host-range promoter pm.the inducible pm promoter integrated into broad-host-range plasmid rk2 replicons can be fine-tuned continuously between the uninduced and maximally induced levels by varying the inducer concentrations. to lower the uninduced background level while still maintaining the inducibility for applications in, for example, metabolic engineering and synthetic (systems) biology, we report here the use of mutations in the pm dna region corresponding to the 5' untranslated region of mrna (utr). five utr var ...201121335387
genome sequences of the high-acetic acid-resistant bacteria gluconacetobacter europaeus lmg 18890t and g. europaeus lmg 18494 (reference strains), g. europaeus 5p3, and gluconacetobacter oboediens 174bp2 (isolated from vinegar).bacteria of the genus gluconacetobacter are usually involved in the industrial production of vinegars with high acetic acid concentrations. we describe here the genome sequence of three gluconacetobacter europaeus strains, a very common bacterial species from industrial fermentors, as well as of a gluconacetobacter oboediens strain.201121441523
Complete genome sequence of NBRC 3288, a unique cellulose-nonproducing strain of Gluconacetobacter xylinus isolated from vinegar.Gluconacetobacter xylinus is involved in the industrial production of cellulose. We have determined the genome sequence of G. xylinus NBRC 3288, a cellulose-nonproducing strain. Comparative analysis of genomes of G. xylinus NBRC 3288 with those of the cellulose-producing strains clarified the genes important for cellulose production in Gluconacetobacter.201122123756
ehrlichia chaffeensis tandem repeat proteins and ank200 are type 1 secretion system substrates related to the repeats-in-toxin exoprotein family.ehrlichia chaffeensis has type 1 and 4 secretion systems (t1ss and t4ss), but the substrates have not been identified. potential substrates include secreted tandem repeat protein (trp) 47, trp120, and trp32, and the ankyrin repeat protein, ank200, that are involved in molecular host-pathogen interactions including dna binding and a network of protein-protein interactions with host targets associated with signaling, transcriptional regulation, vesicle trafficking, and apoptosis. in this study we ...201122919588
quantification of natural populations of gluconacetobacter diazotrophicus and herbaspirillum spp. in sugar cane (saccharum spp.) using differente polyclonal antibodies.the species gluconacetobacter diazotrophicus, herbaspirillum seropedicae and h. rubrisubalbicans are endophytic n2-fixing [diazotrophic] bacteria which colonise not only roots, but also the aerial tissue of sugar cane. however, the technique most commonly used to quantify the populations of these microbes in plants is by culturing serial dilutions of macerates of plant tissues in n free semi-solid media which are only semi-selective for the species/genera [the most probable number (mpn) techniqu ...200924031435
establishing a role for bacterial cellulose in environmental interactions: lessons learned from diverse biofilm-producing proteobacteria.bacterial cellulose (bc) serves as a molecular glue to facilitate intra- and inter-domain interactions in nature. biosynthesis of bc-containing biofilms occurs in a variety of proteobacteria that inhabit diverse ecological niches. the enzymatic and regulatory systems responsible for the polymerization, exportation, and regulation of bc are equally as diverse. though the magnitude and environmental consequences of bc production are species-specific, the common role of bc-containing biofilms is to ...201526635751
bacterial cellulose biosynthesis: diversity of operons, subunits, products, and functions.recent studies of bacterial cellulose biosynthesis, including structural characterization of a functional cellulose synthase complex, provided the first mechanistic insight into this fascinating process. in most studied bacteria, just two subunits, bcsa and bcsb, are necessary and sufficient for the formation of the polysaccharide chain in vitro. other subunits - which differ among various taxa - affect the enzymatic activity and product yield in vivo by modulating (i) the expression of the bios ...201526077867
the structural and functional basis of catalysis mediated by nad(p)h:acceptor oxidoreductase (ferb) of paracoccus denitrificans.ferb from paracoccus denitrificans is a soluble cytoplasmic flavoprotein that accepts redox equivalents from nadh or nadph and transfers them to various acceptors such as quinones, ferric complexes and chromate. the crystal structure and small-angle x-ray scattering measurements in solution reported here reveal a head-to-tail dimer with two flavin mononucleotide groups bound at the opposite sides of the subunit interface. the dimers tend to self-associate to a tetrameric form at higher protein c ...201424817153
bacterial exopolysaccharides: functionality and prospects.diverse structural, functional and valuable polysaccharides are synthesized by bacteria of all taxa and secreted into the external environment. these polysaccharides are referred to as exopolysaccharides and they may either be homopolymeric or heteropolymeric in composition and of diverse high molecular weights (10 to 1000 kda). the material properties of exopolysaccharides have revolutionized the industrial and medical sectors due to their retinue of functional applications and prospects. these ...201223203046
determinants of cofactor specificity for the glucose-6-phosphate dehydrogenase from escherichia coli: simulation, kinetics and evolutionary studies.glucose 6-phosphate dehydrogenases (g6pdhs) from different sources show varying specificities towards nad+ and nadp+ as cofactors. however, it is not known to what extent structural determinants of cofactor preference are conserved in the g6pdh family. in this work, molecular simulations, kinetic characterization of site-directed mutants and phylogenetic analyses were used to study the structural basis for the strong preference towards nadp+ shown by the g6pdh from escherichia coli. molecular dy ...201627010804
a mechanistic explanation linking adaptive mutation, niche change, and fitness advantage for the wrinkly spreader.experimental evolution studies have investigated adaptive radiation in static liquid microcosms using the environmental bacterium pseudomonas fluorescens sbw25. in evolving populations a novel adaptive mutant known as the wrinkly spreader arises within days having significant fitness advantage over the ancestral strain. a molecular investigation of the wrinkly spreader has provided a mechanistic explanation linking mutation with fitness improvement through the production of a cellulose-based bio ...201424551477
structure determination and functional analysis of a chromate reductase from gluconacetobacter hansenii.environmental protection through biological mechanisms that aid in the reductive immobilization of toxic metals (e.g., chromate and uranyl) has been identified to involve specific nadh-dependent flavoproteins that promote cell viability. to understand the enzyme mechanisms responsible for metal reduction, the enzyme kinetics of a putative chromate reductase from gluconacetobacter hansenii (gh-chrr) was measured and the crystal structure of the protein determined at 2.25 å resolution. gh-chrr cat ...201222879982
structure and functional characterization of pyruvate decarboxylase from gluconacetobacter diazotrophicus.bacterial pyruvate decarboxylases (pdc) are rare. their role in ethanol production and in bacterially mediated ethanologenic processes has, however, ensured a continued and growing interest. pdcs from zymomonas mobilis (zmpdc), zymobacter palmae (zppdc) and sarcina ventriculi (svpdc) have been characterized and zmpdc has been produced successfully in a range of heterologous hosts. pdcs from the acetobacteraceae and their role in metabolism have not been characterized to the same extent. examples ...201425369873
metagenome-wide association of microbial determinants of host phenotype in drosophila melanogaster.animal-associated bacteria (microbiota) affect host behaviors and physiological traits. to identify bacterial genetic determinants of microbiota-responsive host traits, we employed a metagenome-wide association (mgwa) approach in two steps. first, we measured two microbiota-responsive host traits, development time and triglyceride (tag) content, in drosophila melanogaster flies monoassociated with each of 41 bacterial strains. the effects of monoassociation on host traits were not confined to pa ...201425271286
uv-b radiation stress causes alterations in whole cell protein profile and expression of certain genes in the rice phyllospheric bacterium enterobacter cloacae.among the different types of uv radiation, uv-b radiation (280-315 nm) has gained much attention mainly due to its increasing incidence on the earth's surface leading to imbalances in natural ecosystems. this study deals with the effects of uv-b radiation on the proteome and gene expression in a rice phyllospheric bacterium, enterobacter cloacae. of the five bacteria isolated from rice leaves, e. cloacae showed the highest level of resistance to uv-b and total killing occurred after 8 h of conti ...201627672388
a molecular description of cellulose biosynthesis.cellulose is the most abundant biopolymer on earth, and certain organisms from bacteria to plants and animals synthesize cellulose as an extracellular polymer for various biological functions. humans have used cellulose for millennia as a material and an energy source, and the advent of a lignocellulosic fuel industry will elevate it to the primary carbon source for the burgeoning renewable energy sector. despite the biological and societal importance of cellulose, the molecular mechanism by whi ...201526034894
16s rrna in situ hybridization followed by flow cytometry for rapid identification of acetic acid bacteria involved in submerged industrial vinegar production.acetic acid bacteria are involved in many biotechnological processes such as vitamin c, gluconic acid, miglitol or acetic acid production, and others. for a technologist trying to control the industrial process, the ability to follow the microbiological development of the process is thus of importance. during the past few years hybridization in a combination with flow cytometry has often been used for this purpose. since vinegar is a liquid, it is an ideal matrix for flow cytometry analysis. in ...201627904400
dying for good: virus-bacterium biofilm co-evolution enhances environmental fitness.commonly used in biotechnology applications, filamentous m13 phage are non-lytic viruses that infect e. coli and other bacteria, with the potential to promote horizontal gene transfer in natural populations with synthetic biology implications for engineering community systems. using the e. coli strain tg1, we have investigated how a selective pressure involving elevated levels of toxic chromate, mimicking that found in some superfund sites, alters population dynamics following infection with eit ...201225114551
identification and characterization of non-cellulose-producing mutants of gluconacetobacter hansenii generated by tn5 transposon mutagenesis.the acs operon of gluconacetobacter is thought to encode acsa, acsb, acsc, and acsd proteins that constitute the cellulose synthase complex, required for the synthesis and secretion of crystalline cellulose microfibrils. a few other genes have been shown to be involved in this process, but their precise role is unclear. we report here the use of tn5 transposon insertion mutagenesis to identify and characterize six non-cellulose-producing (cel(-)) mutants of gluconacetobacter hansenii atcc 23769. ...201324013627
complete genome sequence of gluconacetobacter hansenii strain nq5 (atcc 53582), an efficient producer of bacterial cellulose.this study reports the release of the complete nucleotide sequence of gluconacetobacter hansenii strain nq5 (atcc 53582). this strain was isolated by r. malcolm brown, jr. in a sugar mill in north queensland, australia, and is an efficient producer of bacterial cellulose. the elucidation of the genome will contribute to the study of the molecular mechanisms necessary for cellulose biosynthesis.201627516505
engineering control of bacterial cellulose production using a genetic toolkit and a new cellulose-producing strain.bacterial cellulose is a strong and ultrapure form of cellulose produced naturally by several species of the acetobacteraceae its high strength, purity, and biocompatibility make it of great interest to materials science; however, precise control of its biosynthesis has remained a challenge for biotechnology. here we isolate a strain of komagataeibacter rhaeticus (k. rhaeticus igem) that can produce cellulose at high yields, grow in low-nitrogen conditions, and is highly resistant to toxic chemi ...201627247386
gqqa, a novel protein in komagataeibacter europaeus involved in bacterial quorum quenching and cellulose formation.we report on the functional screening and identification of an active quorum quenching (qq) gene in the komagataeibacter europaeus strain cect 8546, which is a member of the acetic acid bacteria (aab).201627221658
complete genome sequence of a gluconacetobacter hansenii atcc 23769 isolate, ay201, producer of bacterial cellulose and important model organism for the study of cellulose biosynthesis.the cellulose producer and model organism used for the study of cellulose biosynthesis, gluconacetobacter hansenii ay201, is a variant of g. hansenii atcc 23769. we report here the complete nucleotide sequence of g. hansenii ay201, information which may be utilized to further the research into understanding the genes necessary for cellulose biosynthesis.201627516506
detc-based bacterial cellulose bio-curatives for topical treatment of cutaneous leishmaniasis.the treatment of leishmaniasis still relies on drugs with potentially serious adverse effects. herein, we tested a topical formulation of bacterial cellulose (bc) membranes containing diethyldithiocarbamate (detc), a superoxide dismutase 1 inhibitor. leishmania-infected macrophages exposed to bc-detc resulted in parasite killing, without pronounced toxic effects to host cells. this outcome was associated with lower sod1 activity and higher production of superoxide and cytokine mediators. topical ...201627922065
isolation and characterization of two cellulose morphology mutants of gluconacetobacter hansenii atcc23769 producing cellulose with lower crystallinity.gluconacetobacter hansenii, a gram-negative bacterium, produces and secrets highly crystalline cellulose into growth medium, and has long been used as a model system for studying cellulose synthesis in higher plants. cellulose synthesis involves the formation of β-1,4 glucan chains via the polymerization of glucose units by a multi-enzyme cellulose synthase complex (csc). these glucan chains assemble into ordered structures including crystalline microfibrils. acsa is the catalytic subunit of the ...201525790428
what's inside that seed we brew? a new approach to mining the coffee is a critically important agricultural commodity for many tropical states and is a beverage enjoyed by millions of people worldwide. recent concerns over the sustainability of coffee production have prompted investigations of the coffee microbiome as a tool to improve crop health and bean quality. this review synthesizes literature informing our knowledge of the coffee microbiome, with an emphasis on applications of fruit- and seed-associated microbes in coffee production and processing. ...201526162877
the phytohormone ethylene enhances cellulose production, regulates crp/fnrkx transcription and causes differential gene expression within the bacterial cellulose synthesis operon of komagataeibacter (gluconacetobacter) xylinus atcc 53582.komagataeibacter (formerly gluconacetobacter) xylinus atcc 53582 is a plant-associated model organism for bacterial cellulose (bc) biosynthesis. this bacterium inhabits the carposphere where it interacts with fruit through the bi-directional transfer of phytohormones. the majority of research regarding k. xylinus has been focused on identifying and characterizing structural and regulatory factors that control bc biosynthesis, but its ecophysiology has been generally overlooked. ethylene is a phy ...201526733991
the effect of bacterial cellulose membrane compared with collagen membrane on guided bone regeneration.this study was to evaluate the effects of bacterial cellulose (bc) membranes as a barrier membrane on guided bone regeneration (gbr) in comparison with those of the resorbable collagen membranes.201526816579
pinus flexilis and picea engelmannii share a simple and consistent needle endophyte microbiota with a potential role in nitrogen fixation.conifers predominantly occur on soils or in climates that are suboptimal for plant growth. this is generally attributed to symbioses with mycorrhizal fungi and to conifer adaptations, but recent experiments suggest that aboveground endophytic bacteria in conifers fix nitrogen (n) and affect host shoot tissue growth. because most bacteria cannot be grown in the laboratory very little is known about conifer-endophyte associations in the wild. pinus flexilis (limber pine) and picea engelmannii (eng ...201425071746
protection and restitution of gut barrier by probiotics: nutritional and clinical implications.probiotics are beneficial bacteria present in various dietary components and many of these colonize in the human and animal intestine. in the gut probiotics help the host by assisting in maintenance of normal mucosal homeostasis. probiotics not only help maintain normal function of the gut mucosa, but also protect mucosa from injurious factors such as toxins, allergens and pathogens. the beneficial effect of probiotics is mediated by multiple mechanisms, including cytoprotection, cell proliferat ...201324353483
antimicrobial brazilian propolis (epp-af) containing biocellulose membranes as promising biomaterial for skin wound healing.among remarkable discoveries concerning propolis, such as antifungal, antiviral, and antioxidant activities, its anti-inflammatory, and mainly its antibacterial, properties deserve special attention when skin wound healing is concerned. based on this and knowing the distinctive performance of bacterial (bc) membranes on wound healing, in this work it is proposed to demonstrate the potent antimicrobial activity and wound healing properties of a novel propolis containing biocellulose membrane. the ...201323840264
production of bacterial cellulose by gluconacetobacter hansenii uac09 using coffee cherry husk.the work is aimed to investigate the suitability of underutilized coffee cherry husk (cch) for the production and optimization of bacterial cellulose (bc) by gluconacetobacter hansenii uac09 and to study the physico-mechanical properties of bc films. cch extract was used as a carbon source in various concentrations along with other nutritional components such as nitrogen (corn steep liquor, urea) and additives (ethyl alcohol, acetic acid). concentration of cch extract at 1:1 (w/v) along with 8% ...201124425978
production of bacterial cellulose by gluconacetobacter hansenii uac09 using coffee cherry husk.the work is aimed to investigate the suitability of underutilized coffee cherry husk (cch) for the production and optimization of bacterial cellulose (bc) by gluconacetobacter hansenii uac09 and to study the physico-mechanical properties of bc films. cch extract was used as a carbon source in various concentrations along with other nutritional components such as nitrogen (corn steep liquor, urea) and additives (ethyl alcohol, acetic acid). concentration of cch extract at 1:1 (w/v) along with 8% ...201124425978
cellulose crystallinity index: measurement techniques and their impact on interpreting cellulase performance.although measurements of crystallinity index (ci) have a long history, it has been found that ci varies significantly depending on the choice of measurement method. in this study, four different techniques incorporating x-ray diffraction and solid-state 13c nuclear magnetic resonance (nmr) were compared using eight different cellulose preparations. we found that the simplest method, which is also the most widely used, and which involves measurement of just two heights in the x-ray diffractogram, ...201020497524
genome sequence and plasmid transformation of the model high-yield bacterial cellulose producer gluconacetobacter hansenii atcc 53582.bacterial cellulose is a strong, highly pure form of cellulose that is used in a range of applications in industry, consumer goods and medicine. gluconacetobacter hansenii atcc 53582 is one of the highest reported bacterial cellulose producing strains and has been used as a model organism in numerous studies of bacterial cellulose production and studies aiming to increased cellulose productivity. here we present a high-quality draft genome sequence for g. hansenii atcc 53582 and find that in add ...201627010592
structure of the cellulose synthase complex of gluconacetobacter hansenii at 23.4 å resolution.bacterial crystalline cellulose is used in biomedical and industrial applications, but the molecular mechanisms of synthesis are unclear. unlike most bacteria, which make non-crystalline cellulose, gluconacetobacter hansenii extrudes profuse amounts of crystalline cellulose. its cellulose synthase (acsa) exists as a complex with accessory protein acsb, forming a 'terminal complex' (tc) that has been visualized by freeze-fracture tem at the base of ribbons of crystalline cellulose. the catalytic ...201627214134
Displaying items 1 - 42 of 42