| isolation and enzymic properties of levansucrase secreted by acetobacter diazotrophicus srt4, a bacterium associated with sugar cane. | acetobacter diazotrophicus, a nitrogen-fixing bacterium associated with sugar cane, secretes a levansucrase (sucrose-2,6-beta-d-fructan 6-beta-d-fructosyltransferase; ec 2.4.1.10). this enzyme is constitutively expressed and represents more than 70% of the total proteins secreted by strain srt4. the purified protein consists of a single 58 kda polypeptide with an isoelectric point of 5.5. its activity is optimal at ph 5.0. it catalyses transfructosylation from sucrose to a variety of acceptors i ... | 1995 | 7619044 |
| differentiation of capsular polysaccharides from acetobacter diazotrophicus strains isolated from sugarcane. | capsular polysaccharides (cpss) from six representative strains of acetobacter diazotrophicus were isolated and fractionated by gel filtration and anion-exchange chromatography. purified cpss obtained in the non-adsorbed fraction of a deae-sephadex a-25 column were qualitatively and quantitatively analyzed for sugar composition. uronic acid and amino sugars were not detected in all purified cpss. basically the cpss of a. diazotrophicus are composed of rhamnose, mannose, galactose and glucose. th ... | 1995 | 7651237 |
| molecular characterization of the levansucrase gene from the endophytic sugarcane bacterium acetobacter diazotrophicus srt4. | the acetobacter diazotrophicus srt4 gene encoding levansucrase (ec 2.4.1.10) (isda) was isolated from a genomic library. the nucleotide sequence of a 2.3 kb dna fragment sufficient for complementation of a levansucrase-deficient mutant (obtained by ems treatment) was determined. the isda gene (1751 bp) coded for a polypeptide of molecular mass 64.9 kda with an isoelectric point of 5.2. the n-terminal amino acid sequence of the extracellular levansucrase indicated the presence of a precursor prot ... | 1996 | 8704949 |
| structure of the repeating oligosaccharide from the lipopolysaccharide of the nitrogen-fixing bacterium acetobacter diazotrophicus strain pal 5. | acetobacter diazotrophicus is an acid-tolerant nitrogen-fixing bacterium found in roots, rhizosphere, stems, and leaves of sugar cane (saccharum officinarum) cultivated in brazil. the o-polysaccharide from the lipopolysaccharide of the root isolate strain pal 5 has been determined by a combination of methylation analysis and two-dimensional high field nmr spectroscopy. the pentasaccharide repeat has the structure: [formula: see text] minor resonances in the nmr spectra are consistent with the pr ... | 1997 | 9098959 |
| coffea arabica l., a new host plant for acetobacter diazotrophicus, and isolation of other nitrogen-fixing acetobacteria. | acetobacter diazotrophicus was isolated from coffee plant tissues and from rhizosphere soils. isolation frequencies ranged from 15 to 40% and were dependent on soil ph. attempts to isolate this bacterial species from coffee fruit, from inside vesicular-arbuscular mycorrhizal fungi spores, or from mealybugs (planococcus citri) associated with coffee plants were not successful. other acid-producing diazotrophic bacteria were recovered with frequencies of 20% from the coffee rhizosphere. these n2-f ... | 1997 | 9293018 |
| nucleotide sequence of the nifh gene coding for nitrogen reductase in the acetic acid bacterium acetobacter diazotrophicus. | the nifh gene sequence of the nitrogen-fixing bacterium acetobacter diazotrophicus was determined with the use of the polymerase chain reaction and universal degenerate oligonucleotide primers. the gene shows highest pair-wise similarity to the nifh gene of azospirillum brasilense. the phylogenetic relationships of the nifh gene sequences were compared with those inferred from 16s rrna gene sequences. knowledge of the sequence of the nifh gene contributes to the growing database of nifh gene seq ... | 1998 | 9489028 |
| life in grasses: diazotrophic endophytes. | n2-fixing bacteria such as azoarcus spp., herbaspirillum spp, and acetobacter diazotrophicus can infect the interior of gramineous plants without causing symptoms of plant disease but do not survive in soil. like phytopathogens, they can penetrate into central tissues and spread systemically. there is no evidence for an endosymbiosis in living plant cells; however, the bacteria are physiologically active in the plant apoplast. | 1998 | 9587190 |
| effect of high sugar concentration on nitrogenase activity of acetobacter diazotrophicus. | acetobacter diazotrophicus is a nitrogen-fixing bacterium that growth inside sugar cane plant tissue where the sucrose concentration is approximately 10%. the influence of high sugar content on nitrogenase was measured in the presence of oxygen and of nitrogen added in the form of ammonium and amino acids. in all parameters analyzed, 10% sucrose protected nitrogenase against inhibition by oxygen, ammonium, some amino acids, and also to some extent by salt stress. the oxygen concentration at whic ... | 1998 | 9871014 |
| substitution of asp-309 by asn in the arg-asp-pro (rdp) motif of acetobacter diazotrophicus levansucrase affects sucrose hydrolysis, but not enzyme specificity. | beta-fructofuranosidases share a conserved aspartic acid-containing motif (arg-asp-pro; rdp) which is absent from alpha-glucopyranosidases. the role of asp-309 located in the rdp motif of levansucrase (ec 2.4.1.10) from acetobacter diazotrophicus srt4 was studied by site-directed mutagenesis. substitution of asp-309 by asn did not affect enzyme secretion. the kcat of the mutant levansucrase was reduced 75-fold, but its km was similar to that of the wild-type enzyme, indicating that asp-309 plays ... | 1999 | 9895294 |
| phylogenetic identification of two major nitrogen-fixing bacteria associated with sugarcane. | acetobacter diazotrophicus and herbaspirillum seropedicae were identified by genetic methods based on 16s rrna sequences. a specific pcr method in combination with probing was developed for a. diazotrophicus. the pcr system includes four primers, of which the primers named ac (ctgtttcccgcaagggac) and di (gcgccccattgctgggtt) generated an 445 bp amplicon in all of the 11 a. diazotrophicus strains tested. the phylogenetic position of h. seropedicae was determined. h. seropedicae forms with oxalobac ... | 1998 | 9924818 |
| purification and enzymic properties of the fructosyltransferase of streptococcus salivarius atcc 25975. | the recombinant fructosyltransferase (ftf) of streptococcus salivarius was expressed in escherichia coli and purified to electrophoretic homogeneity after a combination of adsorption, ion-exchange and gel-filtration chromatography. the n-terminal signal sequence of the ftf was removed by e. coli at the same site as in its natural host. the purified ftf exhibited maximum activity at ph 6.0 and 37 degrees c, was activated by ca2+, but inhibited by the metal ions cu2+, zn2+, hg2+ and fe3+. the enzy ... | 1999 | 10393084 |
| levansucrase from acetobacter diazotrophicus srt4 is secreted via periplasm by a signal-peptide-dependent pathway. | acetobacter diazotrophicus srt4 secretes a constitutive levansucrase (lsda) (ec 2.4.1.10) that is responsible for sucrose utilization. immunogold electron microscopical studies revealed that lsda accumulates in the periplasm before secretion. the periplasmic and extracellular forms of the enzyme were purified to homogeneity. both proteins exhibited similar physical and biochemical characteristics indicating that lsda adopts its final conformation in the periplasm. the n-terminal sequence of matu ... | 1999 | 10441728 |
| identification, sequencing and structural analysis of a nifa-like gene of acetobacter diazotrophicus. | a recombinant plasmid, pad101, containing a dna fragment of acetobacter diazotrophicus strain pal5 was isolated by its ability to restore nif+ phenotype to a nifa- ntrc- double mutant of azotobacter vinelandii. hybridization with the nifa genes of azospirillum brasilense located the nifa gene more precisely to specific fragments of pad101. dna sequencing of appropriate subclones of pad101 revealed that the nifa gene was adjacent to the nifb gene in a. diazotrophicus, and the 5' end of the nifb g ... | 1999 | 10530336 |
| description of gluconacetobacter sacchari sp. nov., a new species of acetic acid bacterium isolated from the leaf sheath of sugar cane and from the pink sugar-cane mealy bug. | a new species of the genus gluconacetobacter, for which the name gluconacetobacter sacchari sp. nov. is proposed, was isolated from the leaf sheath of sugar cane and from the pink sugar-cane mealy bug, saccharicoccus sacchari, found on sugar cane growing in queensland and northern new south wales, australia. the nearest phylogenetic relatives in the alpha-subclass of the proteobacteria are gluconacetobacter liquefaciens and gluconacetobacter diazotrophicus, which have 98.8-99.3% and 97.9-98.5% 1 ... | 1999 | 10555349 |
| the respiratory system and diazotrophic activity of acetobacter diazotrophicus pal5. | the characteristics of the respiratory system of acetobacter diazotrophicus pal5 were investigated. increasing aeration (from 0.5 to 4.0 liters of air min(-1) liter of medium(-1)) had a strong positive effect on growth and on the diazotrophic activity of cultures. cells obtained from well-aerated and diazotrophically active cultures possessed a highly active, membrane-bound electron transport system with dehydrogenases for nadh, glucose, and acetaldehyde as the main electron donors. ethanol, suc ... | 1999 | 10559164 |
| molecular detection of gluconacetobacter sacchari associated with the pink sugarcane mealybug saccharicoccus sacchari (cockerell) and the sugarcane leaf sheath microenvironment by fish and pcr. | molecular tools for the detection of the newly described acetic acid bacterium gluconacetobacter sacchari from the pink sugarcane mealybug, saccharicoccus sacchari cockerell (homiptera: pseudococcidae), and in the sugarcane leaf sheath microenvironment were developed. g. sacchari specific 16s rrna-targeted oligonucleotide primers were designed and used in pcr amplification of g. sacchari dna directly from mealybugs, and in a nested pcr to detect low numbers of the bacteria from sugarcane leaf sh ... | 2000 | 10620720 |
| natural endophytic occurrence of acetobacter diazotrophicus in pineapple plants. | the presence of endophytic acetobacter diazotrophicus was tested for pineapple plants (ananas comosus [l.] merr.) grown in the field. diazotrophic bacteria were isolated from the inner tissues of surface sterilized roots, stems, and leaves of pineapple plants. phenotypic tests permitted the selection of presumptive nitrogen-fixing a. diazotrophicus isolates. restriction fragment length polymorphisms (rflps) of small subunit (ssu) rdna using total dna digested with endonuclease sphi and with endo ... | 2000 | 10790517 |
| functional bradyrhizobium japonicum nifa expression under a hybrid nptii-nifh promoter in e. coli and acetobacter diazotrophicus srt4. | a hybrid promoter consisting of the in tandem fusion of the tn5 nptii and the klebsiella pneumoniae nifh promoters was constructed to study the functionality of the nif genes transcriptional activator nifa from bradyrhizobium japonicum in two different host bacteria. beta-galactosidase experiments in e. coli revealed that the hybrid nptii-nifh promoter can behave as a constitutive or a nifa-inducible promoter depending on the aeration conditions. expression of the b. japonicum nifa from the hybr ... | 1998 | 10932742 |
| azospirillum, a free-living nitrogen-fixing bacterium closely associated with grasses: genetic, biochemical and ecological aspects. | azospirillum represents the best characterized genus of plant growth-promoting rhizobacteria. other free-living diazotrophs repeatedly detected in association with plant roots, include acetobacter diazotrophicus, herbaspirillum seropedicae, azoarcus spp. and azotobacter. four aspects of the azospirillum-plant root interaction are highlighted: natural habitat, plant root interaction, nitrogen fixation and biosynthesis of plant growth hormones. each of these aspects is dealt with in a comparative ... | 2000 | 10978548 |
| structural levansucrase gene (lsda) constitutes a functional locus conserved in the species gluconacetobacter diazotrophicus. | levansucrase (ec 2.4.1.10) was identified as a constitutive exoenzyme in 14 gluconacetobacter diazotrophicus strains recovered from different host plants in diverse geographical regions. the enzyme, consisting of a single 60-kda polypeptide, hydrolysed sucrose to synthesise oligofructans and levan. sugar-cane-associated strains of the most abundant genotype (electrophoretic type 1) showed maximal values of levansucrase production. these values were three-fold higher than those of the isolates re ... | 2000 | 10985751 |
| cloning and sequencing of the levansucrase gene from acetobacter xylinum nci 1005. | the levansucrase gene (lsxa) was cloned from the genomic dna of acetobacter xylinum nci 1005, and the nucleotide sequence of the lsxa gene (1,293 bp) was determined. the deduced amino acid sequence of the lsxa gene showed 57.4% and 46.2% identity with the levansucrases from zymomonas mobilis and erwinia amylovora, respectively, while only 35.2% identity with that from acetobacter diazotrophicus. the gene product of lsxa (lsxa) that was overproduced in e. coli coded for a polypeptide of molecular ... | 2000 | 10997873 |
| binding of soluble glycoproteins from sugarcane juice to cells of acetobacter diazotrophicus. | sugarcane produces two different pools of glycoproteins containing a heterofructan as glycidic moiety, tentatively defined as high-molecular mass (hmmg) and mid-molecular mass (mmmg) glycoproteins. both kinds of glycoproteins can be recovered in sugarcane juice. fluorescein-labelled glycoproteins are able to bind to acetobacter diazotrophicus cells, a natural endophyte of sugarcane. this property implies the aggregation of bacterial cells in liquid culture after addition of hmmg or mmmg. anionic ... | 2000 | 11032311 |
| the carbon source influences the energetic efficiency of the respiratory chain of n2-fixing acetobacter diazotrophicus. | acetobacter diazotrophicus is a diazotrophic bacterium that colonizes sugarcane tissues. glucose is oxidized to gluconate in the periplasm prior to uptake and metabolism. a membrane-bound glucose dehydrogenase quinoenzyme [which contains pyrroloquinoline quinone (pqq) as the prosthetic group] is involved in that oxidation. gluconate is oxidized further via the hexose monophosphate pathway and tricarboxylic acid cycle. a. diazotrophicus pal3 was grown in a chemostat with atmospheric nitrogen as t ... | 2000 | 11092633 |
| characterization of a major cluster of nif, fix, and associated genes in a sugarcane endophyte, acetobacter diazotrophicus. | a major 30.5-kb cluster of nif and associated genes of acetobacter diazotrophicus (syn. gluconacetobacter diazotrophicus), a nitrogen-fixing endophyte of sugarcane, was sequenced and analyzed. this cluster represents the largest assembly of contiguous nif-fix and associated genes so far characterized in any diazotrophic bacterial species. northern blots and promoter sequence analysis indicated that the genes are organized into eight transcriptional units. the overall arrangement of genes is most ... | 2000 | 11092875 |
| transfer of acetobacter oboediens sokollek et al 1998 and acetobacter intermedius boesch et al. 1998 to the genus gluconacetobacter as gluconacetobacter oboediens comb. nov. and gluconacetobacter intermedius comb. nov. | acetobacter oboediens sokollek et al. 1998 and acetobacter intermedius boesch et al. 1998 are transferred to the genus gluconacetobacter as gluconacetobacter oboediens comb. nov. and gluconacetobacter intermedius comb. nov. because, on the basis of their 16s rrna gene sequences, the type strains of both species are located in the cluster of the genus gluconacetobacter along with those of gluconacetobacter xylinus, gluconacetobacter europaeus, gluconacetobacter hansenii, gluconacetobacter liquefa ... | 2000 | 11155999 |
| fructo-oligosaccharides production by the gluconacetobacter diazotrophicus levansucrase expressed in the methylotrophic yeast pichia pastoris. | levansucrase (lsda) (ec 2.4.1.10) from gluconacetobacter diazotrophicus (formerly acetobacter diazotrophicus) yields high levels of fructo-oligosaccharides (fos) from sucrose. a dna fragment encoding the precursor lsda lacking the first 57 amino acids was fused to the pho1 signal sequence under the control of the pichia pastoris-alcohol oxidase 1 (aox1) promoter. methanol induction of a p. pastoris strain harboring a single copy of the lsda expression cassette integrated in the genome resulted i ... | 2001 | 11166804 |
| comparison of benefit to sugarcane plant growth and 15n2 incorporation following inoculation of sterile plants with acetobacter diazotrophicus wild-type and nif- mutants strains. | the ability of the nitrogen-fixing bacterial endophyte acetobacter diazotrophicus strain pal5 to enhance the growth of sugarcane sp70-1143 was evaluated in the growth chamber, greenhouse, and field by comparing plants inoculated with wild-type and nif mutant mad3a in two independent experiments. the wild-type and nif mutant strains colonized sugarcane plants equally and persisted in mature plants. in n-deficient conditions, sugarcane plants inoculated with a. diazotrophicus pal5 generally grew b ... | 2001 | 11277433 |
| further observations on the interaction between sugar cane and gluconacetobacter diazotrophicus under laboratory and greenhouse conditions. | sugar cane (saccharum spp.) variety sp 70-1143 was inoculated with gluconacetobacter diazotrophicus strain pal5 (atcc 49037) in two experiments. in experiment 1 the bacteria were inoculated into a modified, low sucrose ms medium within which micropropagated plantlets were rooted. after 10 d there was extensive anatomical evidence of endophytic colonization by g. diazotrophicus, particularly in lower stems, where high numbers of bacteria were visible within some of the xylem vessels. the identity ... | 2001 | 11413211 |
| novel nitrogen-fixing acetic acid bacteria, gluconacetobacter johannae sp. nov. and gluconacetobacter azotocaptans sp. nov., associated with coffee plants. | diazotrophic bacteria were isolated, in two different years, from the rhizosphere and rhizoplane of coffee (coffea arabica l.) plants cultivated in mexico; they were designated as type dor and type sad isolates. they showed characteristics of the family acetobacteraceae, having some features in common with gluconacetobacter (formerly acetobacter) diazotrophicus, the only known n2-fixing species of the acetic acid bacteria, but they differed from this species with regard to several characteristic ... | 2001 | 11491326 |
| glutamine synthetase from acetobacter diazotrophicus: properties and regulation. | glutamine synthetase from acetobacter diazotrophicus, an endophyte originally isolated from sugarcane, was studied as a step in the identification of mechanisms underlying the role of a. diazotrophicus as a major supplier of fixed nitrogen to its host plant. the enzyme was purified and partially characterized. it was also shown that the enzyme is regulated by adenylylation in response to the nitrogen source. interestingly, there is no upregulation of the synthesis of the enzyme under diazotrophi ... | 2001 | 11520611 |
| response of the endophytic diazotroph gluconacetobacter diazotrophicus on solid media to changes in atmospheric partial o(2) pressure. | gluconacetobacter diazotrophicus is an n(2)-fixing endophyte isolated from sugarcane. g. diazotrophicus was grown on solid medium at atmospheric partial o(2) pressures (po(2)) of 10, 20, and 30 kpa for 5 to 6 days. using a flowthrough gas exchange system, nitrogenase activity and respiration rate were then measured at a range of atmospheric po(2) (5 to 60 kpa). nitrogenase activity was measured by h(2) evolution in n(2)-o(2) and in ar-o(2), and respiration rate was measured by co(2) evolution in ... | 2001 | 11571174 |
| energy generation by extracellular aldose oxidation in n(2)-fixing gluconacetobacter diazotrophicus. | gluconacetobacter diazotrophicus pal3 was grown in a chemostat with n(2) and mixtures of xylose and gluconate. xylose was oxidized to xylonate, which was accumulated in the culture supernatants. biomass yields and carbon from gluconate incorporated into biomass increased with the rate of xylose oxidation. by using metabolic balances it is demonstrated that extracellular xylose oxidation led n(2)-fixing g. diazotrophicus cultures to increase the efficiency of energy generation. | 2002 | 11916732 |
| molecular cloning and expression in escherichia coli of an exo-levanase gene from the endophytic bacterium gluconacetobacter diazotrophicus srt4. | gluconacetobacter diazotrophicus produces levan from sucrose by a secreted levansucrase (lsda). a levanase-encoding gene ( lsdb), starting 51 bp downstream of the lsda gene, was cloned from strain srt4. the lsdb gene (1605 bp) encodes a protein (calculated molecular mass 58.4 kda) containing a putative 36-amino-acid signal peptide at the n-terminus. the deduced amino acid sequence shares 34%, 33%, 32%, and 29% identities with levanases from actinomyces naeslundii, bacillus subtilis, paenibacillu ... | 2002 | 12029520 |
| evidence for protection of nitrogenase from o(2) by colony structure in the aerobic diazotroph gluconacetobacter diazotrophicus. | gluconacetobacter diazotrophicus is an endophytic diazotroph of sugarcane which exhibits nitrogenase activity when growing in colonies on solid media. nitrogenase activity of g. diazotrophicus colonies can adapt to changes in atmospheric partial pressure of oxygen (po(2)). this paper investigates whether colony structure and the position of g. diazotrophicus cells in the colonies are components of the bacterium's ability to maintain nitrogenase activity at a variety of atmospheric po(2) values. ... | 2002 | 12177323 |
| a nitrogen-fixing endophyte of sugarcane stems (a new role for the apoplast). | the intercellular spaces of sugarcane (saccharum officinarum l.) stem parenchyma are filled with solution (determined by cryoscanning microscopy), which can be removed aseptically by centrifugation. it contained 12% sucrose (suc; ph 5.5.) and yielded pure cultures of an acid-producing bacterium (approximately 104 bacteria/ml extracted fluid) on n-poor medium containing 10% suc (ph 5.5). this bacterium was identical with the type culture of acetobacter diazotrophicus, a recently discovered n2-fix ... | 1994 | 12232271 |
| gluconacetobacter diazotrophicus, a sugar cane endosymbiont, produces a bacteriocin against xanthomonas albilineans, a sugar cane pathogen. | gluconacetobacter diazotrophicus in liquid culture secretes proteins into the medium. both medium containing gluconacetobacter protein and a solution of this protein after acetone precipitation appeared to inhibit the growth of xanthomonas albilineans in solid culture. this apparent inhibition of bacterial growth has, in fact, been revealed to be lysis of bacterial cells, as demonstrated by transmission electron microscopy. fractionation of the gluconacetobacter protein mixture in size-exclusion ... | 2002 | 12234008 |
| evidence for conformational protection of nitrogenase against oxygen in gluconacetobacter diazotrophicus by a putative fesii protein. | the mechanisms protecting nitrogenase in gluconacetobacter diazotrophicus from damage by oxygen were studied. evidence is provided suggesting that in g. diazotrophicus these mechanisms include respiratory protection as well as conformational protection in which a putative fesii shethna protein is involved. | 2002 | 12270840 |
| isolation and characterization of the glnd gene of gluconacetobacter diazotrophicus, encoding a putative uridylyltransferase/uridylyl-removing enzyme. | the glnd gene of gluconacetobacter diazotrophicus was isolated by complementation of the azotobacter vinelandii glnd (nfrx) mutant strain mv17 using a plafr3 cosmid library. the 5 kb chromosomal dna region encoding the glnd gene on cosmid pad401 was identified by introduction of deletions as well as subcloning of restriction fragments followed by subsequent dna sequencing. three open reading frames were identified with the deduced amino acid sequence of orf1 showing significant homologies to kno ... | 2002 | 12384297 |
| effect of some abiotic factors on the biological activity of gluconacetobacter diazotrophicus. | the effect of some abiotic factors, dryness, heat and salinity on the growth and biological activity of gluconacetobacter diazotrophicus, and the influence of a salt stress on some enzymes involved in carbon metabolism of these bacteria is studied under laboratory conditions. | 2003 | 12911701 |
| identification of three genes encoding p(ii)-like proteins in gluconacetobacter diazotrophicus: studies of their role(s) in the control of nitrogen fixation. | in our studies on the regulation of nitrogen metabolism in gluconacetobacter diazotrophicus, an endophytic diazotroph of sugarcane, three glnb-like genes were identified and their role(s) in the control of nitrogen fixation was studied. sequence analysis revealed that one p(ii) protein-encoding gene, glnb, was adjacent to a glna gene (encoding glutamine synthetase) and that two other p(ii) protein-encoding genes, identified as glnk1 and glnk2, were located upstream of amtb1 and amtb2, respective ... | 2003 | 13129958 |
| crystallization and preliminary x-ray diffraction analysis of levansucrase (lsda) from gluconacetobacter diazotrophicus srt4. | the endophytic bacterium gluconacetobacter diazotrophicus srt4 secretes a constitutively expressed levansucrase (lsda; ec 2.4.1.10), which converts sucrose to fructo-oligosaccharides and levan. fully active lsda was purified to high homogeneity by non-denaturing reversed-phase hplc and was crystallized at room temperature by the hanging-drop vapour-diffusion method using ammonium sulfate and ethanol as precipitants. the crystals are extremely sensitive, but native data have been collected to 2.5 ... | 2004 | 14684923 |
| population dynamics of gluconacetobacter diazotrophicus in sugarcane cultivars and its effect on plant growth. | different experiments have estimated that the contribution of biological nitrogen fixation (bnf) is largely variable among sugarcane cultivars. which bacteria are the most important in sugarcane-associated bnf is unknown. however, gluconacetobacter diazotrophicus has been suggested as a strong candidate responsible for the bnf observed. in the present study, bacteria-free micropropagated plantlets of five sugarcane cultivars were inoculated with three g. diazotrophicus strains belonging to diffe ... | 2003 | 14722690 |
| a type ii protein secretory pathway required for levansucrase secretion by gluconacetobacter diazotrophicus. | the endophytic diazotroph gluconacetobacter diazotrophicus secretes a constitutively expressed levansucrase (lsda, ec 2.4.1.10) to utilize plant sucrose. lsda, unlike other extracellular levansucrases from gram-negative bacteria, is transported to the periplasm by a signal-peptide-dependent pathway. we identified an unusually organized gene cluster encoding at least the components lsdg, -o, -e, -f, -h, -i, -j, -l, -m, -n, and -d of a type ii secretory system required for lsda translocation acros ... | 2004 | 15262940 |
| a putative new endophytic nitrogen-fixing bacterium pantoea sp. from sugarcane. | to isolate and identify endophytic nitrogen-fixing bacteria in sugarcane growing in cuba without chemical fertilizers. | 2004 | 15281930 |
| indole-3-acetic acid biosynthesis is deficient in gluconacetobacter diazotrophicus strains with mutations in cytochrome c biogenesis genes. | gluconacetobacter diazotrophicus is an endophyte of sugarcane frequently found in plants grown in agricultural areas where nitrogen fertilizer input is low. recent results from this laboratory, using mutant strains of g. diazotrophicus unable to fix nitrogen, suggested that there are two beneficial effects of g. diazotrophicus on sugarcane growth: one dependent and one not dependent on nitrogen fixation. a plant growth-promoting substance, such as indole-3-acetic acid (iaa), known to be produced ... | 2004 | 15292139 |
| occurrence of gluconacetobacter diazotrophicus in tropical and subtropical plants of western ghats, india. | endophytic bacteria were isolated from the tissues of surface sterilized roots, stems, and leaves of fifty different crop plants. phenotypic, biochemical tests and species-specific pcr assay permitted identification of four isolates of gluconacetobacter diazotrophicus from root tissues of carrot (daucus carota l.), raddish (raphanus sativus l.), beetroot (beta vulgaris l.) and coffee (coffea arabica l.). further the plant growth promoting traits such as nitrogenase activity, production of phytoh ... | 2004 | 15462523 |
| influence of carbon and nitrogen sources on growth, nitrogenase activity, and carbon metabolism of gluconacetobacter diazotrophicus. | the effects of different carbon and nitrogen sources on the growth, nitrogenase activity, and carbon metabolism of gluconacetobacter diazotrophicus were investigated. the amino acids asparagine, aspartic acid, and glutamic acid affected microbial growth and nitrogenase activity. several enzymatic activities involved in the tricarboxylic acid cycle were affected by the carbon source used. in addition, glucose and gluconate significantly increased the oxygen consumption (respiration rate) of whole ... | 2004 | 15644929 |
| crystal structure of levansucrase from the gram-negative bacterium gluconacetobacter diazotrophicus. | the endophytic gram-negative bacterium gluconacetobacter diazotrophicus srt4 secretes a constitutively expressed levansucrase (lsda, ec 2.4.1.10), which converts sucrose into fructooligosaccharides and levan. the enzyme is included in gh (glycoside hydrolase) family 68 of the sequence-based classification of glycosidases. the three-dimensional structure of lsda has been determined by x-ray crystallography at a resolution of 2.5 a (1 a=0.1 nm). the structure was solved by molecular replacement us ... | 2005 | 15869470 |
| natural association of gluconacetobacter diazotrophicus and diazotrophic acetobacter peroxydans with wetland rice. | the family acetobacteraceae currently includes three known nitrogen-fixing species, gluconacetobacter diazotrophicus, g. johannae and g. azotocaptans. in the present study, acetic acid-producing nitrogen-fixing bacteria were isolated from four different wetland rice varieties cultivated in the state of tamilnadu, india. most of these isolates were identified as g. diazotrophicus on the basis of their phenotypic characteristics and pcr assays using specific primers for that species. based on 16s ... | 2005 | 15900973 |
| nitrogenase proteins from gluconacetobacter diazotrophicus, a sugarcane-colonizing bacterium. | gluconacetobacter diazotrophicus pal-5 grew well and expressed nitrogenase activity in the absence of nh4+ and at initial o2 concentrations greater than 5% in the culture atmosphere. g. diazotrophicus nitrogenase consisted of two components, gd1 and gd2, which were difficult to separate but were purified individually to homogeneity. their compositions were very similar to those of azotobacter vinelandii nitrogenase, however, all subunits were slightly smaller in size. the purified gd1 protein co ... | 2005 | 15925553 |
| design, development, and use of molecular primers and probes for the detection of gluconacetobacter species in the pink sugarcane mealybug. | molecular tools for the species-specific detection of gluconacetobacter sacchari, gluconacetobacter diazotrophicus, and gluconacetobacter liquefaciens from the pink sugarcane mealybug (psmb) saccharicoccus sacchari cockerell (homiptera: pseudococcidae) were developed and used in polymerase chain reactions (pcr) and in fluorescence in situ hybridizations (fish) to better understand the microbial diversity and the numerical significance of the acetic acid bacteria in the psmb microenvironment. the ... | 2005 | 16047097 |
| history on the biological nitrogen fixation research in graminaceous plants: special emphasis on the brazilian experience. | this review covers the history on biological nitrogen fixation (bnf) in graminaceous plants grown in brazil, and describes research progress made over the last 40 years, most of which was coordinated by johanna döbereiner. one notable accomplishment during this period was the discovery of several nitrogen-fixing bacteria such as the rhizospheric (beijerinckia fluminensis and azotobacter paspali), associative (azospirillum lipoferum, a. brasilense, a. amazonense) and the endophytic (herbaspirillu ... | 2005 | 16127558 |
| antagonism of gluconacetobacter diazotrophicus (a sugarcane endosymbiont) against xanthomonas albilineans (pathogen) studied in alginate-immobilized sugarcane stalk tissues. | xanthomonas albilineans, a pathogenic bacterium that produces leaf scald disease of sugarcane, secretes a xanthan-like gum that invades both xylem and phloem of the host. xanthan production has been verified after experimental infection of stalk segments of healthy plants. moreover, gluconacetobacter diazotrophicus is a nitrogen-fixing endosymbiont of sugarcane plants that antagonizes with x. albilineans by impeding the production of the bacterial gum. the physiological basis of this antagonism ... | 2005 | 16233803 |
| isolation from gluconacetobacter diazotrophicus cell walls of specific receptors for sugarcane glycoproteins, which act as recognition factors. | glycoproteins from sugarcane stalks have been isolated from plants field-grown by size-exclusion chromatography. some of these glycoproteins, previously labelled with fluorescein isothiocyanate, are able to bind to the cell wall of the sugarcane endophyte, n2-fixing gluconacetobacter diazotrophicus, and largely removed after washing the bacterial cells with sucrose. this implies that sugarcane glycoproteins use beta-(1-->2)-fructofuranosyl fructose domains in their glycosidic moiety to bind to s ... | 2005 | 16233885 |
| antagonism among gluconacetobacter diazotrophicus strains in culture media and in endophytic association. | in this study the antagonistic activity among 55 gluconacetobacter diazotrophicus strains, belonging to 13 electrophoretic types (ets), in culture media was analyzed. antagonistic effects were seen only in strains belonging to two ets named et-1 and et-3. two out of 29 et-1 strains, and 3 out of 7 et-3 strains of g. diazotrophicus showed antagonistic effects against many other strains belonging to all the ets of this species analyzed, and against closely related strains of gluconacetobacter spec ... | 2005 | 16329972 |
| limited genetic diversity in the endophytic sugarcane bacterium acetobacter diazotrophicus. | acetobacter diazotrophicus isolates that originated from different sugarcane cultivars growing in diverse geographic regions of mexico and brazil were shown to have limited genetic diversity. measurements of polymorphism in the electrophoretic mobilities of metabolic enzymes revealed that the mean genetic diversity per enzyme locus (among the four electrophoretic types distinguished) was 0.064. the results of the genetic analysis indicate that the genetic structure of a. diazotrophicus is clonal ... | 1994 | 16349254 |
| nitrogen compounds in the apoplastic sap of sugarcane stem: some implications in the association with endophytes. | several nitrogen compounds were identified and quantified in the apoplastic and symplastic sap of sugarcane stems. the sap of stems was composed mainly of soluble sugars, which constituted 95% of the total organic compounds detected. sap also contained nitrogen compounds, with amino acids (50-70% of n) and proteins (20-30% of n), being the main nitrogenous substances, as well as inorganic forms as ammonium, nitrite and nitrate, in low concentrations (<20% of n). serine, proline, alanine and aspa ... | 2006 | 16360806 |
| glucose metabolism in batch and continuous cultures of gluconacetobacter diazotrophicus pal 3. | periplasmic glucose oxidation (by way of a pyrrolo-quinoline-quinone [pqq]-linked glucose dehydrogenase [gdh]) was observed in continuous cultures of gluconacetobacter diazotrophicus regardless of the carbon source (glucose or gluconate) and the nitrogen source (n(2) or nh(3)). its synthesis was stimulated by conditions of high energetic demand (i.e., n(2)-fixation) and/or c-limitation. under c-excess conditions, pqq-gdh synthesis increased with the glucose concentration in the culture medium. i ... | 2006 | 16479355 |
| symbiosome-like intracellular colonization of cereals and other crop plants by nitrogen-fixing bacteria for reduced inputs of synthetic nitrogen fertilizers. | it has been forecast that the challenge of meeting increased food demand and protecting environmental quality will be won or lost in maize, rice and wheat cropping systems, and that the problem of environmental nitrogen enrichment is most likely to be solved by substituting synthetic nitrogen fertilizers by the creation of cereal crops that are able to fix nitrogen symbiotically as legumes do. in legumes, rhizobia present intracellularly in membrane-bound vesicular compartments in the cytoplasm ... | 2005 | 16512210 |
| further evidence that the n(inf2)-fixing endophytic bacterium from the intercellular spaces of sugarcane stems is acetobacter diazotrophicus. | nitrogen-fixing bacteria, isolated from the sugar solution in intercellular spaces of sugarcane stems, were compared with the type strain of acetobacter diazotrophicus (pal-5) and found to be congruent with it in all characters studied. these characters were 37 morphological and biochemical tests, cellular fatty acid composition, and nitrogenase activity. the nitrogenase activity was measured by acetylene reduction and h(inf2) evolution and found to be unusual in that the h(inf2) evolution was s ... | 1995 | 16535026 |
| genetic structure of acetobacter diazotrophicus populations and identification of a new genetically distant group. | a total of 55 isolates of acetobacter diazotrophicus recovered from diverse sucrose-rich host plants and from mealybugs associated with sugarcane plants were characterized by the electrophoretic mobilities of 12 metabolic enzymes. we identified seven different electrophoretic types (ets), six of which are closely related within a genetic distance of 0.195 and exhibit high dna-dna homology. the seventh et was largely divergent, separated at a genetic distance of 0.53, and had only 54% dna homolog ... | 1995 | 16535102 |
| n-fertilizer saving by the inoculation of gluconacetobacter diazotrophicus and herbaspirillum sp. in micropropagated sugarcane plants. | colonization of micropropagated sugarcane plants by gluconacetobacter diazotrophicus and herbaspirillum sp. was confirmed by a dot-immunoblot assay. in all, a 45-day short-term and 180-day long-term experiments conducted on micropropagated sugarcane plants of co 86032, a sugar rich popular variety in south india, indicated the usefulness of these diazotrophs as plant growth promoting bacteria. co-inoculation of these two bacteria enhanced the biomass considerably under n-limited condition in the ... | 2006 | 16765840 |
| respiratory system of gluconacetobacter diazotrophicus pal5. evidence for a cyanide-sensitive cytochrome bb and cyanide-resistant cytochrome ba quinol oxidases. | in highly aerobic environments, gluconacetobacter diazotrophicus uses a respiratory protection mechanism to preserve nitrogenase activity from deleterious oxygen. here, the respiratory system was examined in order to ascertain the nature of the respiratory components, mainly of the cyanide sensitive and resistant pathways. the membranes of g. diazotrophicus contain q(10), q(9) and pqq in a 13:1:6.6 molar ratios. uv(360 nm) photoinactivation indicated that ubiquinone is the electron acceptor for ... | 2006 | 16934215 |
| solubilization of zinc compounds by the diazotrophic, plant growth promoting bacterium gluconacetobacter diazotrophicus. | gluconacetobacter diazotrophicus an endophytic diazotroph also encountered as rhizosphere bacterium is reported to possess different plant growth promoting characteristics. in this study, we assessed the zinc solubilizing potential of g. diazotrophicus under in vitro conditions with different zn compounds using glucose or sucrose as carbon sources. g. diazotrophicus showed variations in their solubilization potential with the strains used and the zn compounds tested. g. diazotrophicus pal5 effic ... | 2007 | 16956644 |
| solubilization of insoluble zinc compounds by gluconacetobacter diazotrophicus and the detrimental action of zinc ion (zn2+) and zinc chelates on root knot nematode meloidogyne incognita. | to examine the zinc (zn) solubilization potential and nematicidal properties of gluconacetobacter diazotrophicus. methods and results: atomic absorption spectrophotometer, differential pulse polarography and gas chromatography coupled mass spectrometry were used to estimate the total zn and zn(2+) ions and identify the organic acids present in the culture supernatants. the effect of culture filtrate of zn-amended g. diazotrophicus pal5 on meloidogyne incognita in tomato was examined under gnotob ... | 2007 | 17309498 |
| enumeration, isolation and identification of diazotrophs from korean wetland rice varieties grown with long-term application of n and compost and their short-term inoculation effect on rice plants. | this study has been aimed (i) to isolate and identify diazotrophs from korean rice varieties; (ii) to examine the long-term effect of n and compost on the population dynamics of diazotrophs and (iii) to realize the shot-term inoculation effect of these diazotrophs on rice seedlings. | 2007 | 17381741 |
| effects of the inoculation of burkholderia vietnamensis and related endophytic diazotrophic bacteria on grain yield of rice. | during a survey of endophytic diazotrophic bacteria associated with different rice varieties in tamilnadu, some "endophytes" were obtained. thirteen bacterial isolates from surface-sterilized roots and shoots were obtained in pure culture, which produced indole acetic acid (iaa) and reduced acetylene to ethylene. polymerase chain reaction (pcr) amplification confirmed the presence of nif-h gene in all the isolates. morphological, biochemical, and molecular characteristics indicated that all of t ... | 2008 | 17406771 |
| ecological occurrence of gluconacetobacter diazotrophicus and nitrogen-fixing acetobacteraceae members: their possible role in plant growth promotion. | gluconacetobacter diazotrophicus has a long-standing history of bacterial-plant interrelationship as a symbiotic endophyte capable of fixing atmospheric nitrogen. in low nitrogen fertilized sugarcane fields it plays a significant role and its occurrence was realised in most of the sugarcane growing countries. in this mini review, the association of g. diazotrophicus with sugarcane, other crop plants and with various hosts is discussed. the factors affecting survival in the rhizosphere and the pu ... | 2008 | 17574542 |
| insights into polymer versus oligosaccharide synthesis: mutagenesis and mechanistic studies of a novel levansucrase from bacillus megaterium. | a novel levansucrase was identified in the supernatant of a cell culture of bacillus megaterium dsm319. in order to test for the contribution of specific amino acid residues to levansucrase catalysis, the wild-type enzyme along with 16 variants based on sequence alignments and structural information were heterologously produced in escherichia coli. the purified enzymes were characterized kinetically and the product spectrum of each variant was determined. comparison of the x-ray structures of th ... | 2007 | 17608626 |
| validation of a tn5 transposon mutagenesis system for gluconacetobacter diazotrophicus through characterization of a flagellar mutant. | gluconacetobacter diazotrophicus is a nitrogen-fixing bacterium, which was originally isolated from the interior of sugarcane plants. the genome of strain pal5 of g. diazotrophicus has been completely sequenced and a next step is the functional characterization of its genes. the aim of this study was to establish an efficient mutagenesis method, using the commercial tn5 transposon ez::tn5<kan-2>tnp transposome (epicentre). up to 1 x 10(6) mutants per microgram of transposome were generated in a ... | 2008 | 18060666 |
| zinc metal solubilization by gluconacetobacter diazotrophicus and induction of pleomorphic cells. | gluconacetobacter diazotrophicus strain pal5 exhibited a minimum inhibitory concentration value of 11 mm in an lgi medium amended with zncl2. when an lgi medium was amended with zn metal, solubilization halos were observed in a plate assay, and further solubilization was confirmed in a broth assay. the maximum solubilization was recorded after 120 h with a 0.1% zn metal amendment. during solubilization, the culture growth and ph of the broth were indirectly correlated. using a fourier transform ... | 2007 | 18062225 |
| recent advances in nitrogen-fixing acetic acid bacteria. | nitrogen is an essential plant nutrient, widely applied as n-fertilizer to improve yield of agriculturally important crops. an interesting alternative to avoid or reduce the use of n-fertilizers could be the exploitation of plant growth-promoting bacteria (pgpb), capable of enhancing growth and yield of many plant species, several of agronomic and ecological significance. pgpb belong to diverse genera, including azospirillum, azotobacter, herbaspirillum, bacillus, burkholderia, pseudomonas, rhiz ... | 2008 | 18177965 |
| the pqq-alcohol dehydrogenase of gluconacetobacter diazotrophicus. | the oxidation of ethanol to acetic acid is the most characteristic process in acetic acid bacteria. gluconacetobacter diazotrophicus is rather unique among the acetic acid bacteria as it carries out nitrogen fixation and is a true endophyte, originally isolated from sugar cane. aside its peculiar life style, ga. diazotrophicus, possesses a constitutive membrane-bound oxidase system for ethanol. the alcohol dehydrogenase complex (adh) of ga. diazotrophicus was purified to homogeneity from the mem ... | 2008 | 18321602 |
| protein expression profile of gluconacetobacter diazotrophicus pal5, a sugarcane endophytic plant growth-promoting bacterium. | this is the first broad proteomic description of gluconacetobacter diazotrophicus, an endophytic bacterium, responsible for the major fraction of the atmospheric nitrogen fixed in sugarcane in tropical regions. proteomic coverage of g. diazotrophicus pal5 was obtained by two independent approaches: 2-de followed by maldi-tof or tof-tof ms and 1-de followed by chromatography in a c18 column online coupled to an esi-q-tof or esi-it mass spectrometer. the 583 identified proteins were sorted into fu ... | 2008 | 18340630 |
| a comparative proteomic analysis of gluconacetobacter diazotrophicus pal5 at exponential and stationary phases of cultures in the presence of high and low levels of inorganic nitrogen compound. | a proteomic view of g. diazotrophicus pal5 at the exponential (e) and stationary phases (s) of cultures in the presence of low (l) and high levels (h) of combined nitrogen is presented. the proteomes analyzed on 2d-gels showed 131 proteins (42e+32s+29h+28l) differentially expressed by g. diazotrophicus, from which 46 were identified by combining mass spectrometry and bioinformatics tools. proteins related to cofactor, energy and dna metabolisms and cytoplasmic ph homeostasis were differentially ... | 2008 | 18662807 |
| transcriptional regulation and signal-peptide-dependent secretion of exolevanase (lsdb) in the endophyte gluconacetobacter diazotrophicus. | gluconacetobacter diazotrophicus utilizes plant sucrose with a constitutively expressed levansucrase (lsda), producing extracellular levan, which may be degraded under energetically unfavored conditions. reverse transcriptase-pcr analysis revealed that lsda and the downstream exolevanase gene (lsdb) form an operon. lsdb transcription was induced during growth with low fructose concentrations (0.44 to 33 mm) and repressed by glucose. transport of lsdb to the periplasm involved n-terminal signal p ... | 2009 | 19139238 |
| identification and characterization of gluconacetobacter diazotrophicus mutants defective in the solubilization of phosphorus and zinc. | gluconacetobacter diazotrophicus is a plant-growth-promoting bacterium, which is able to colonize sugarcane and other plant species of economic importance. the potentially beneficial effects promoted by this bacterium on plants are nitrogen-fixation, production of phythormones, action against pathogens and mineral nutrient solubilization. in this study, the molecular mechanisms associated with phosphorus and zinc solubilization were analyzed. a transposon mutant library was constructed and scree ... | 2009 | 19340412 |
| gluconacetobacter diazotrophicus elicits a sugarcane defense response against a pathogenic bacteria xanthomonas albilineans. | a new role for the plant growth-promoting nitrogen-fixing endophytic bacteria gluconacetobacter diazotrophicus has been identified and characterized while it is involved in the sugarcane-xanthomonas albilineans pathogenic interactions. living g.diazotrophicus possess and/or produce elicitor molecules which activate the sugarcane defense response resulting in the plant resistance to x. albilineans, in this particular case controlling the pathogen transmission to emerging agamic shoots. a total of ... | 2006 | 19516988 |
| glycine betaine enhances growth of nitrogen-fixing bacteria gluconacetobacter diazotrophicus pal5 under saline stress conditions. | in this study, the effect of glycine betaine as osmoprotectant compound for gluconacetobacter diazotrophicus pal5 was evaluated by kinetic growth parameters. batch fermentation assays were performed employing media supplemented with different sodium chloride concentrations to simulate saline stress conditions. salt concentrations of 50-300 mm led to decreased cell concentrations, while the maximum specific growth rates and cell productivities were reduced at concentrations above 100-mm nacl. sal ... | 2009 | 19688374 |
| complete genome sequence of the sugarcane nitrogen-fixing endophyte gluconacetobacter diazotrophicus pal5. | gluconacetobacter diazotrophicus pal5 is an endophytic diazotrophic bacterium that lives in association with sugarcane plants. it has important biotechnological features such as nitrogen fixation, plant growth promotion, sugar metabolism pathways, secretion of organic acids, synthesis of auxin and the occurrence of bacteriocins. | 2009 | 19775431 |
| proteome of gluconacetobacter diazotrophicus co-cultivated with sugarcane plantlets. | gluconacetobacter diazotrophicus is a micro-aerobic bacterium able to fix atmospheric nitrogen in endophytic mode. a proteomic approach was used to analyze proteins differentially expressed in the presence and absence of sugarcane plantlets. two-dimensional gel electrophoresis (2-de) showed 42 spots with altered levels of expression. analysis of these spots by matrix-assisted laser desorption ionization time-of-flight in tandem (maldi-tof-tof) identified 38 proteins. differentially expressed pro ... | 2010 | 20026003 |
| the membrane-bound quinohemoprotein alcohol dehydrogenase from gluconacetobacter diazotrophicus pal5 carries a [2fe-2s] cluster. | gluconacetobacter diazotrophicus stands out among the acetic acid bacteria as it fixes dinitrogen and is a true endophyte. it has a set of constitutive enzymes to oxidize ethanol and acetaldehyde which is upregulated during n(2)-dependent growth. the membrane-bound alcohol dehydrogenase (adh) is a heterodimer (subunit i approximately 72 kda, subunit ii approximately 44 kda) and constitutes an important component of this organism. adh of ga. diazotrophicus is a typical quinohemoprotein with one p ... | 2010 | 20148520 |
| colonization of sorghum and wheat by seed inoculation with gluconacetobacter diazotrophicus. | colonization of sorghum and wheat after seed inoculation with gluconacetobacter diazotrophicus strains pal 5 and uap 5541/prgs561 (containing the marker gene gusa) was studied by colony counting and microscopic observation of plant tissues. inoculum levels as low as 10(2) cfu per seed were enough for root colonization and further spreading in aerial tissues. rhizoplane colonization was around 7 log cfu g(-1) (fresh weight). g. diazotrophicus was found inside sorghum and wheat roots with populati ... | 2010 | 20361236 |
| symbiosome-like intracellular colonization of cereals and other crop plants by nitrogen-fixing bacteria for reduced inputs of synthetic nitrogen fertilizers. | it has been forecast that the challenge of meeting increased food demand and protecting environmental quality will be won or lost in maize, rice and wheat cropping systems, and that the problem of environmental nitrogen enrichment is most likely to be solved by substituting synthetic nitrogen fertilizers by the creation of cereal crops that are able to fix nitrogen symbiotically as legumes do. in legumes, rhizobia present intracellularly in membrane-bound vesicular compartments in the cytoplasm ... | 2005 | 20549443 |
| monitoring the colonization of sugarcane and rice plants by the endophytic diazotrophic bacterium gluconacetobacter diazotrophicus marked with gfp and gusa reporter genes. | to evaluate the colonization process of sugarcane plantlets and hydroponically grown rice seedlings by gluconacetobacter diazotrophicus strain pal5 marked with the gusa and gfp reporter genes. | 2010 | 20666985 |
| antioxidant pathways are up-regulated during biological nitrogen fixation to prevent ros-induced nitrogenase inhibition in gluconacetobacter diazotrophicus. | gluconacetobacter diazotrophicus, an endophyte isolated from sugarcane, is a strict aerobe that fixates n(2). this process is catalyzed by nitrogenase and requires copious amounts of atp. nitrogenase activity is extremely sensitive to inhibition by oxygen and reactive oxygen species (ros). however, the elevated oxidative metabolic rates required to sustain biological nitrogen fixation (bnf) may favor an increased production of ros. here, we explored this paradox and observed that ros levels are, ... | 2010 | 20697694 |
| molecular and catalytic properties of the aldehyde dehydrogenase of gluconacetobacter diazotrophicus, a quinoheme protein containing pyrroloquinoline quinone, cytochrome b, and cytochrome c. | several aldehyde dehydrogenase (aldh) complexes have been purified from the membranes of acetic acid bacteria. the enzyme structures and the chemical nature of the prosthetic groups associated with these enzymes remain a matter of debate. we report here on the molecular and catalytic properties of the membrane-bound aldh complex of the diazotrophic bacterium gluconacetobacter diazotrophicus. the purified aldh complex is a heterodimer comprising two subunits of 79.7 and 50 kda, respectively. reve ... | 2010 | 20802042 |
| gluconacetobacter diazotrophicus levansucrase is involved in tolerance to nacl, sucrose and desiccation, and in biofilm formation. | gluconacetobacter diazotrophicus is a nitrogen-fixing bacterium and endophyte of sugarcane, which expresses levansucrase, a fructosyltransferase exoenzyme with sucrose hydrolytic and levan biosynthetic activities. as a result of their physical properties, the levan can provide protection against stress caused by abiotic or biotic factors and participate in the formation of biofilms. in this study, we investigated the construction and function of a levansucrase-defective mutant of g. diazotrophic ... | 2010 | 21103984 |
| quantitative proteomic analysis of the interaction between the endophytic plant-growth-promoting bacterium gluconacetobacter diazotrophicus and sugarcane. | gluconacetobacter diazotrophicus is a plant-growth-promoting bacterium that colonizes sugarcane. in order to investigate molecular aspects of the g. diazotrophicus-sugarcane interaction, we performed a quantitative mass spectrometry-based proteomic analysis by (15)n metabolic labeling of bacteria, root samples, and co-cultures. overall, more than 400 proteins were analyzed and 78 were differentially expressed between the plant-bacterium interaction model and control cultures. a comparative analy ... | 2011 | 21190439 |
| two genome sequences of the same bacterial strain, gluconacetobacter diazotrophicus pal 5, suggest a new standard in genome sequence submission. | gluconacetobacter diazotrophicus pal 5 is of agricultural significance due to its ability to provide fixed nitrogen to plants. consequently, its genome sequence has been eagerly anticipated to enhance understanding of endophytic nitrogen fixation. two groups have sequenced the pal 5 genome from the same source (atcc 49037), though the resulting sequences contain a surprisingly high number of differences. therefore, an optical map of pal 5 was constructed in order to determine which genome assemb ... | 2010 | 21304715 |
| high levan accumulation in transgenic tobacco plants expressing the gluconacetobacter diazotrophicus levansucrase gene. | bacterial levansucrase (ec 2.4.1.10) converts sucrose into non-linear levan consisting of long β(2,6)-linked fructosyl chains with β(2,1) branches. bacterial levan has wide food and non-food applications, but its production in industrial reactors is costly and low yielding. here, we report the constitutive expression of gluconacetobacter diazotrophicus levansucrase (lsda) fused to the vacuolar targeting pre-pro-peptide of onion sucrose:sucrose 1-fructosyltransferase (1-sst) in tobacco, a crop th ... | 2011 | 21540065 |
| exopolysaccharide production is required for biofilm formation and plant colonization by the nitrogen-fixing endophyte gluconacetobacter diazotrophicus. | the genome of the endophytic diazotrophic bacterial species gluconacetobacter diazotrophicus strain pal5 (pal5) revealed the presence of a gum gene cluster. in this study, the gumd gene homologue, which is predicted to be responsible for the first step in eps production, was insertionally inactivated and the resultant mutant (mgd) was functionally studied. the mutant mgd presented normal growth and nitrogen (n2) fixation levels, but did not produce eps when grown on different carbon sources. mgd ... | 2011 | 21809982 |
| The active (ADHa) and inactive (ADHi) forms of the PQQ-alcohol dehydrogenase from Gluconacetobacter diazotrophicus differ in their respective oligomeric structures and redox state of their corresponding prosthetic groups. | The membrane-bound alcohol dehydrogenase of Gluconacetobacter diazotrophicus contains one pyrroloquinoline quinone moiety (PQQ), one [2Fe-2S] cluster and four c-type cytochromes. Here, we describe a novel and inactive enzyme. ADHi, similarly to ADHa is a heterodimer of 72 and 44 kDa subunits and contains the expected prosthetic groups. However, ADHa showed a threefold molecular mass as compared to ADHi. Noteworthy, the PQQ, the [2Fe-2S] and most of the cytochromes in purified ADHi is in the oxid ... | 2011 | 22188488 |
| Recombinant Gluconacetobacter diazotrophicus containing Cry1Ac gene codes for 130-kDa toxin protein. | Recombinant Gluconacetobacter diazotrophicus containing Cry1Ac gene from Bacillus thuringiensis var. kurstaki borne on pKT230, shuttle vector, was generated. PCR amplification of Cry1Ac gene present in recombinant G. diazotrophicus yielded a 278-bp DNA product. The nitrogenase assay has revealed that the recombinant G. diazotrophicus in sugarcane stem produced similar levels of nitrogenase compared to wild-type G. diazotrophicus. The presence of 130-kDa protein in apoplastic fluid from sugarcane ... | 2011 | 21934327 |
| the shifts of diazotrophic communities in spring and summer associated with coral galaxea astreata, pavona decussata, and porites lutea. | the coral holobiont often resides in oligotrophic waters; both coral cells and their symbiotic dinoflagellates possess ammonium assimilation enzymes and potentially benefit from the nitrogen fixation of coral-associated diazotrophs. however, the seasonal dynamics of coral-associated diazotrophs are not well characterized. here, the seasonal variations of diazotrophic communities associated with three corals, galaxea astreata, pavona decussata, and porites lutea, were studied using nifh gene ampl ... | 2016 | 27920768 |
| microbial inoculation improves growth of oil palm plants (elaeis guineensis jacq.). | introduction of diazotrophic rhizobacteria to oil palm tissues during the in vitro micropropagation process establishes an early associative interaction between the plant cells and bacteria. in the association, the diazotrophs provide the host plants with phytohormones and fixed nitrogen. this study was conducted to observe growth of bacterised tissue cultured oil palm plants under ex vitro conditions after 280 days of growth. root dry weight, shoot dry weight, root volume, bacterial colonisatio ... | 2009 | 24575180 |
| 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 ... | 2009 | 24031435 |
| drought tolerance conferred to sugarcane by association with gluconacetobacter diazotrophicus: a transcriptomic view of hormone pathways. | sugarcane interacts with particular types of beneficial nitrogen-fixing bacteria that provide fixed-nitrogen and plant growth hormones to host plants, promoting an increase in plant biomass. other benefits, as enhanced tolerance to abiotic stresses have been reported to some diazotrophs. here we aim to study the effects of the association between the diazotroph gluconacetobacter diazotrophicus pal5 and sugarcane cv. sp70-1143 during water depletion by characterizing differential transcriptome pr ... | 2014 | 25489849 |
| diversity of bacteria nesting the plant cover of north sinai deserts, egypt. | north sinai deserts were surveyed for the predominant plant cover and for the culturable bacteria nesting their roots and shoots. among 43 plant species reported, 13 are perennial (e.g. fagonia spp., pancratium spp.) and 30 annuals (e.g. bromus spp., erodium spp.). eleven species possessed rhizo-sheath, e.g. cyperus capitatus, panicum turgidum and trisetaria koelerioides. microbiological analyses demonstrated: the great diversity and richness of associated culturable bacteria, in particular nitr ... | 2012 | 25685397 |
| 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 ... | 2014 | 25369873 |