| 1. |
Steiner P,
Sauer U,
( 2003 ) Overexpression of the ATP-dependent helicase RecG improves resistance to weak organic acids in Escherichia coli. PMID : 12898065 : DOI : 10.1007/s00253-003-1405-5 Abstract >>
Increased resistance to several weak organic acids was conferred on Escherichia coli by overexpression of the ATP-dependent helicase RecG and, to a lesser extent, by overexpressing the helicase RuvAB. This property of helicases was identified by reproducible selection of recG-bearing clones from genomic libraries of the acetate-resistant species Acetobacter aceti and Staphylococcus capitis. We show that overexpression of RecG from both species, but also from E. coli, increased the maximum biomass concentration attained by E. coli cultures that were grown in the presence of various weak organic acids and uncouplers. Furthermore, overexpression of RecG from A. aceti significantly improved the maximum growth rates of E. coli under weak organic acid challenge. Based on the known role of RecG in DNA replication/repair, our data provide a first indication that weak organic acids negatively affect DNA replication and/or repair, and that these negative effects may be counteracted by helicase activity.
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2. |
Hanada T,
Kashima Y,
Kosugi A,
Koizumi Y,
Yanagida F,
Udaka S,
( 2001 ) A gene encoding phosphatidylethanolamine N-methyltransferase from Acetobacter aceti and some properties of its disruptant. PMID : 11826972 : DOI : 10.1271/bbb.65.2741 Abstract >>
Phosphatidylcholine (PC) is a major component of membranes not only in eukaryotes, but also in several bacteria, including Acetobacter. To identify the PC biosynthetic pathway and its role in Acetobacter sp., we have studied Acetobacter aceti IFO3283, which is characterized by high ethanol oxidizing ability and high resistance to acetic acid. The pmt gene of A. aceti, encoding phosphatidylethanolamine N-methyltransferase (Pmt), which catalyzes methylation of phosphatidylethanolamine (PE) to PC, has been cloned and sequenced. One recombinant plasmid that complemented the PC biosynthesis was isolated from a gene library of the genomic DNA of A. aceti. The pmt gene encodes a polypeptide with molecular mass of either 25125, 26216, or 29052 for an about 27-kDa protein. The sequence of this gene showed significant similarity (44.3% identity in the similar sequence region) with the Rhodobacter sphaeroides pmtA gene which is involved in PE N-methylation. When the pmt gene was expressed in E. coli, which lacks PC, the Pmt activity and PC formation were clearly demonstrated. A. aceti strain harboring an interrupted pmt allele, pmt::Km, was constructed. The pmt disruption was confirmed by loss of Pmt and PC, and by Southern blot analyses. The null pmt mutant contained no PC, but tenfold more PE and twofold more phosphatidylglycerol (PG). The pmt disruptant did not show any dramatic effects on growth in basal medium supplemented with ethanol, but the disruption caused slow growth in basal medium supplemented with acetate. These results suggest that the lack of PC in the A. aceti membrane may be compensated by the increases of PE and PG by an unknown mechanism, and PC in A. aceti membrane is related to its acetic acid tolerance.
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3. |
Starks CM,
Francois JA,
MacArthur KM,
Heard BZ,
Kappock TJ,
( 2007 ) Atomic-resolution crystal structure of thioredoxin from the acidophilic bacterium Acetobacter aceti. PMID : 17192591 : DOI : 10.1110/ps.062519707 PMC : PMC2222842 Abstract >>
The crystal structure of thioredoxin (AaTrx) from the acetic acid bacterium Acetobacter aceti was determined at 1 A resolution. This is currently the highest resolution crystal structure available for any thioredoxin. Thioredoxins facilitate thiol-disulfide exchange, a process that is expected to be slow at the low pH values encountered in the A. aceti cytoplasm. Despite the apparent need to function at low pH, neither the active site nor the surface charge distribution of AaTrx is notably different from that of Escherichia coli thioredoxin. Apparently the ancestral thioredoxin was sufficiently stable for use in A. aceti or the need to interact with multiple targets constrained the variation of surface residues. The AaTrx structure presented here provides a clear view of all ionizable protein moieties and waters, a first step in understanding how thiol-disulfide exchange might occur in a low pH cytoplasm, and is a basis for biophysical studies of the mechanism of acid-mediated unfolding. The high resolution of this structure should be useful for computational studies of thioredoxin function, protein structure and dynamics, and side-chain ionization.
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4. |
Francois JA,
Starks CM,
Sivanuntakorn S,
Jiang H,
Ransome AE,
Nam JW,
Constantine CZ,
Kappock TJ,
( 2006 ) Structure of a NADH-insensitive hexameric citrate synthase that resists acid inactivation. PMID : 17087502 : DOI : 10.1021/bi061083k DOI : 10.1021/bi061083k Abstract >>
Acetobacter aceti converts ethanol to acetic acid, and strains highly resistant to both are used to make vinegar. A. aceti survives acetic acid exposure by tolerating cytoplasmic acidification, which implies an unusual adaptation of cytoplasmic components to acidic conditions. A. aceti citrate synthase (AaCS), a hexameric type II citrate synthase, is required for acetic acid resistance and, therefore, would be expected to function at low pH. Recombinant AaCS has intrinsic acid stability that may be a consequence of strong selective pressure to function at low pH, and unexpectedly high thermal stability for a protein that has evolved to function at approximately 30 degrees C. The crystal structure of AaCS, complexed with oxaloacetate (OAA) and the inhibitor carboxymethyldethia-coenzyme A (CMX), was determined to 1.85 A resolution using protein purified by a tandem affinity purification procedure. This is the first crystal structure of a "closed" type II CS, and its active site residues interact with OAA and CMX in the same manner observed in the corresponding type I chicken CS.OAA.CMX complex. While AaCS is not regulated by NADH, it retains many of the residues used by Escherichia coli CS (EcCS) for NADH binding. The surface of AaCS is abundantly decorated with basic side chains and has many fewer uncompensated acidic charges than EcCS; this constellation of charged residues is stable in varied pH environments and may be advantageous in the A. aceti cytoplasm.
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5. |
Constantine CZ,
Starks CM,
Mill CP,
Ransome AE,
Karpowicz SJ,
Francois JA,
Goodman RA,
Kappock TJ,
( 2006 ) Biochemical and structural studies of N5-carboxyaminoimidazole ribonucleotide mutase from the acidophilic bacterium Acetobacter aceti. PMID : 16819818 : DOI : 10.1021/bi060465n Abstract >>
N5-carboxyaminoimidazole ribonucleotide (N5-CAIR) mutase (PurE) catalyzes the reversible interconversion of acid-labile compounds N5-CAIR and 4-carboxy-5-aminoimidazole ribonucleotide (CAIR). We have examined PurE from the acidophilic bacterium Acetobacter aceti (AaPurE), focusing on its adaptation to acid pH and the roles of conserved residues His59 and His89. Both AaPurE and Escherichia coli PurE showed quasi-reversible acid-mediated inactivation, but wt AaPurE was much more stable at pH 3.5, with a > or = 20 degrees C higher thermal unfolding temperature at all pHs. His89 is not essential and does not function as part of a proton relay system. The kcat pH-rate profile was consistent with the assignment of pK1 to unproductive protonation of bound nucleotide and pK2 to deprotonation of His59. A 1.85 A resolution crystal structure of the inactive mutant H59N-AaPurE soaked in CAIR showed that protonation of CAIR C4 can occur in the absence of His59. The resulting species, modeled as isoCAIR [4(R)-carboxy-5-iminoimidazoline ribonucleotide], is strongly stabilized by extensive interactions with the enzyme and a water molecule. The carboxylate moiety is positioned in a small pocket proposed to facilitate nucleotide decarboxylation in the forward direction (N5-CAIR --> CAIR) [Meyer, E., Kappock, T. J., Osuji, C., and Stubbe, J. (1999) Biochemistry 38, 3012-3018]. Comparisons with model studies suggest that in the reverse (nonbiosynthetic) direction PurE favors protonation of CAIR C4. We suggest that the essential role of protonated His59 is to lower the barrier to decarboxylation by stabilizing a CO2-azaenolate intermediate.
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6. |
Francois JA,
Kappock TJ,
( 2007 ) Alanine racemase from the acidophile Acetobacter aceti. PMID : 16843006 : DOI : 10.1016/j.pep.2006.05.016 Abstract >>
Acetobacter aceti converts ethanol to acetic acid, and survives acetic acid exposure by tolerating cytoplasmic acidification. Alanine racemase (Alr) is a pyridoxal 5' phosphate (PLP) -dependent enzyme that catalyzes the interconversion of the d- and l-isomers of alanine and has a basic pH optimum. Since d-alanine is essential for peptidoglycan biosynthesis, Alr must somehow function in the acidic cytoplasm of A. aceti. We report the partial purification of native A. aceti Alr (AaAlr) and evidence that it is a rather stable enzyme. The C-terminus of AaAlr has a strong resemblance to the ssrA-encoded protein degradation signal, which thwarted initial protein expression experiments. High-activity AaAlr forms lacking a protease recognition sequence were expressed in Escherichia coli and purified. Biophysical and enzymological experiments confirm that AaAlr is intrinsically acid-resistant, yet has the catalytic properties of an ordinary Alr.
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7. |
Nakano S,
Fukaya M,
Horinouchi S,
( 2006 ) Putative ABC transporter responsible for acetic acid resistance in Acetobacter aceti. PMID : 16391084 : DOI : 10.1128/AEM.72.1.497-505.2006 PMC : PMC1352267 Abstract >>
Two-dimensional gel electrophoretic analysis of the membrane fraction of Acetobacter aceti revealed the presence of several proteins that were produced in response to acetic acid. A 60-kDa protein, named AatA, which was mostly induced by acetic acid, was prepared; aatA was cloned on the basis of its NH2-terminal amino acid sequence. AatA, consisting of 591 amino acids and containing ATP-binding cassette (ABC) sequences and ABC signature sequences, belonged to the ABC transporter superfamily. The aatA mutation with an insertion of the neomycin resistance gene within the aatA coding region showed reduced resistance to acetic acid, formic acid, propionic acid, and lactic acid, whereas the aatA mutation exerted no effects on resistance to various drugs, growth at low pH (adjusted with HCl), assimilation of acetic acid, or resistance to citric acid. Introduction of plasmid pABC101 containing aatA under the control of the Escherichia coli lac promoter into the aatA mutant restored the defect in acetic acid resistance. In addition, pABC101 conferred acetic acid resistance on E. coli. These findings showed that AatA was a putative ABC transporter conferring acetic acid resistance on the host cell. Southern blot analysis and subsequent nucleotide sequencing predicted the presence of aatA orthologues in a variety of acetic acid bacteria belonging to the genera Acetobacter and Gluconacetobacter. The fermentation with A. aceti containing aatA on a multicopy plasmid resulted in an increase in the final yield of acetic acid.
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8. |
Trcek J,
( 2005 ) Quick identification of acetic acid bacteria based on nucleotide sequences of the 16S-23S rDNA internal transcribed spacer region and of the PQQ-dependent alcohol dehydrogenase gene. PMID : 16261863 : DOI : 10.1016/j.syapm.2005.05.001 Abstract >>
Acetic acid bacteria (AAB) are well known for oxidizing different ethanol-containing substrates into various types of vinegar. They are also used for production of some biotechnologically important products, such as sorbose and gluconic acids. However, their presence is not always appreciated since certain species also spoil wine, juice, beer and fruits. To be able to follow AAB in all these processes, the species involved must be identified accurately and quickly. Because of inaccuracy and very time-consuming phenotypic analysis of AAB, the application of molecular methods is necessary. Since the pairwise comparison among the 16S rRNA gene sequences of AAB shows very high similarity (up to 99.9%) other DNA-targets should be used. Our previous studies showed that the restriction analysis of 16S-23S rDNA internal transcribed spacer region is a suitable approach for quick affiliation of an acetic acid bacterium to a distinct group of restriction types and also for quick identification of a potentially novel species of acetic acid bacterium (Trcek & Teuber 2002; Trcek 2002). However, with the exception of two conserved genes, encoding tRNAIle and tRNAAla, the sequences of 16S-23S rDNA are highly divergent among AAB species. For this reason we analyzed in this study a gene encoding PQQ-dependent ADH as a possible DNA-target. First we confirmed the expression of subunit I of PQQ-dependent ADH (AdhA) also in Asaia, the only genus of AAB which exhibits little or no ADH-activity. Further we analyzed the partial sequences of adhA among some representative species of the genera Acetobacter, Gluconobacter and Gluconacetobacter. The conserved and variable regions in these sequences made possible the construction of A. acetispecific oligonucleotide the specificity of which was confirmed in PCR-reaction using 45 well-defined strains of AAB as DNA-templates. The primer was also successfully used in direct identification of A. aceti from home made cider vinegar as well as for revealing the misclassification of strain IFO 3283 into the species A. aceti.
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9. |
Okamoto-Kainuma A,
Yan W,
Fukaya M,
Tukamoto Y,
Ishikawa M,
Koizumi Y,
( 2004 ) Cloning and characterization of the dnaKJ operon in Acetobacter aceti. PMID : 16233640 : DOI : 10.1016/S1389-1723(04)70216-9 Abstract >>
The dnaKJ operon of Acetobacter aceti was cloned and sequenced. The profile of the gene configuration was similar to that of other alpha-proteobacteria. In the DnaK and DnaJ proteins of A. aceti, the characteristic domains/motifs reported in other organisms were well conserved. This operon was transcribed in response to a temperature shift and exposure to ethanol/acetic acid. The overexpression of this operon in A. aceti resulted in improved growth compared to the control strain at high temperature or in the presence of ethanol, suggesting a correlation to resistance against stressors present during fermentation, although the overexpression did not increase the resistance to acetic acid.
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10. |
Settembre EC,
Chittuluru JR,
Mill CP,
Kappock TJ,
Ealick SE,
( 2004 ) Acidophilic adaptations in the structure of Acetobacter aceti N5-carboxyaminoimidazole ribonucleotide mutase (PurE). PMID : 15388921 : DOI : 10.1107/S090744490401858X Abstract >>
The crystal structure of Acetobacter aceti PurE was determined to a resolution of 1.55 A and is compared with the known structures of the class I PurEs from a mesophile, Escherichia coli, and a thermophile, Thermotoga maritima. Analyses of the general factors that increase protein stability are examined as potential explanations for the acid stability of A. aceti PurE. Increased inter-subunit hydrogen bonding and an increased number of arginine-containing salt bridges appear to account for the bulk of the increased acid stability. A chain of histidines linking two active sites is discussed in the context of the proton transfers catalyzed by the enzyme.
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11. |
Nakano S,
Fukaya M,
Horinouchi S,
( 2004 ) Enhanced expression of aconitase raises acetic acid resistance in Acetobacter aceti. PMID : 15183880 : DOI : 10.1016/j.femsle.2004.05.007 Abstract >>
Acetobacter spp. are used for industrial vinegar production because of their high ability to oxidize ethanol to acetic acid and high resistance to acetic acid. Two-dimensional gel electrophoretic analysis of a soluble fraction of Acetobacter aceti revealed the presence of several proteins whose production was enhanced, to various extents, in response to acetic acid in the medium. A protein with an apparent molecular mass of 100 kDa was significantly enhanced in amount by acetic acid and identified to be aconitase by NH2-terminal amino acid sequencing and subsequent gene cloning. Amplification of the aconitase gene by use of a multicopy plasmid in A. aceti enhanced the enzymatic activity and acetic acid resistance. These results showed that aconitase is concerned with acetic acid resistance. Enhancement of the aconitase activity turned out to be practically useful for acetic acid fermentation, because the A. aceti transformant harboring multiple copies of the aconitase gene produced a higher concentration of acetic acid with a reduced growth lag-time.
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12. |
Fukaya M,
Takemura H,
Okumura H,
Kawamura Y,
Horinouchi S,
Beppu T,
( 1990 ) Cloning of genes responsible for acetic acid resistance in Acetobacter aceti. PMID : 2156811 : DOI : 10.1128/jb.172.4.2096-2104.1990 PMC : PMC208709 Abstract >>
Five acetic acid-sensitive mutants of Acetobacter aceti subsp. aceti no. 1023 were isolated by mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine. Three recombinant plasmids that complemented the mutations were isolated from a gene bank of the chromosome DNA of the parental strain constructed in Escherichia coli by using cosmid vector pMVC1. One of these plasmids (pAR1611), carrying about a 30-kilobase-pair (kb) fragment that conferred acetic acid resistance to all five mutants, was further analyzed. Subcloning experiments indicated that a 8.3-kb fragment was sufficient to complement all five mutations. To identify the mutation loci and genes involved in acetic acid resistance, insertional inactivation was performed by insertion of the kanamycin resistance gene derived from E. coli plasmid pACYC177 into the cloned 8.3-kb fragment and successive integration into the chromosome of the parental strain. The results suggested that three genes, designated aarA, aarB, and aarC, were responsible for expression of acetic acid resistance. Gene products of these genes were detected by means of overproduction in E. coli by use of the lac promoter. The amino acid sequence of the aarA gene product deduced from the nucleotide sequence was significantly similar to those of the citrate synthases (CSs) of E. coli and other bacteria. The A. aceti mutants defective in the aarA gene were found to lack CS activity, which was restored by introduction of a plasmid containing the aarA gene. A mutation in the CS gene of E. coli was also complemented by the aarA gene. These results indicate that aarA is the CS gene.
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13. |
Quintero Y,
Poblet M,
Guillamón JM,
Mas A,
( 2009 ) Quantification of the expression of reference and alcohol dehydrogenase genes of some acetic acid bacteria in different growth conditions. PMID : 19200331 : DOI : 10.1111/j.1365-2672.2008.04046.x Abstract >>
The aim of this study was to develop a reliable system to analyse the expression of the pyrroloquinoline quinone (PQQ)-alcohol dehydrogenase (ADH) and test its ability to predict the growth and oxidative activity of some acetic acid bacteria (AAB). Specific primers were designed for use in RT-PCR to quantify ADH expression and several housekeeping genes in four species of AAB. 16S rRNA gene was selected as an internal control. The relative expression of adhA was measured in Acetobacter aceti, Acetobacter pasteurianus, Gluconacetobacter hansenii and Gluconobacter oxydans grown in two media that had glucose or ethanol as the carbon source. AAB adhA expression was shown to be related to the two Acetobacter species' ability to oxidise and grow on ethanol, whereas G. oxydans were unable to grow on ethanol and the growth of Ga. hansenii was not related to adhA expression. The differential expression of ADH could be a marker to analyse both growth and oxidation ability in some AAB, especially those of the genus Acetobacter. Several housekeeping genes were tested in AAB and after growth in different media and it was evident that only the ribosomal coding genes were adequate as reference genes for RT-PCR.
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14. |
Okamoto-Kainuma A,
Ehata Y,
Ikeda M,
Osono T,
Ishikawa M,
Kaga T,
Koizumi Y,
( 2008 ) Hydrogen peroxide resistance of Acetobacter pasteurianus NBRC3283 and its relationship to acetic acid fermentation. PMID : 18838821 : DOI : 10.1271/bbb.80136 Abstract >>
The bacterium Acetobacter pasteurianus can ferment acetic acid, a process that proceeds at the risk of oxidative stress. To understand the stress response, we investigated catalase and OxyR in A. pasteurianus NBRC3283. This strain expresses only a KatE homolog as catalase, which is monofunctional and growth dependent. Disruption of the oxyR gene increased KatE activity, but both the katE and oxyR mutant strains showed greater sensitivity to hydrogen peroxide as compared to the parental strain. These mutant strains showed growth similar to the parental strain in the ethanol oxidizing phase, but their growth was delayed when cultured in the presence of acetic acid and of glycerol and during the acetic acid peroxidation phase. The results suggest that A. pasteurianus cells show different oxidative stress responses between the metabolism via the membrane oxidizing pathway and that via the general aerobic pathway during acetic acid fermentation.
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15. |
Mullins EA,
Francois JA,
Kappock TJ,
( 2008 ) A specialized citric acid cycle requiring succinyl-coenzyme A (CoA):acetate CoA-transferase (AarC) confers acetic acid resistance on the acidophile Acetobacter aceti. PMID : 18502856 : DOI : 10.1128/JB.00405-08 PMC : PMC2447011 Abstract >>
Microbes tailor macromolecules and metabolism to overcome specific environmental challenges. Acetic acid bacteria perform the aerobic oxidation of ethanol to acetic acid and are generally resistant to high levels of these two membrane-permeable poisons. The citric acid cycle (CAC) is linked to acetic acid resistance in Acetobacter aceti by several observations, among them the oxidation of acetate to CO2 by highly resistant acetic acid bacteria and the previously unexplained role of A. aceti citrate synthase (AarA) in acetic acid resistance at a low pH. Here we assign specific biochemical roles to the other components of the A. aceti strain 1023 aarABC region. AarC is succinyl-coenzyme A (CoA):acetate CoA-transferase, which replaces succinyl-CoA synthetase in a variant CAC. This new bypass appears to reduce metabolic demand for free CoA, reliance upon nucleotide pools, and the likely effect of variable cytoplasmic pH upon CAC flux. The putative aarB gene is reassigned to SixA, a known activator of CAC flux. Carbon overflow pathways are triggered in many bacteria during metabolic limitation, which typically leads to the production and diffusive loss of acetate. Since acetate overflow is not feasible for A. aceti, a CO(2) loss strategy that allows acetic acid removal without substrate-level (de)phosphorylation may instead be employed. All three aar genes, therefore, support flux through a complete but unorthodox CAC that is needed to lower cytoplasmic acetate levels.
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16. |
Inoue T,
Sunagawa M,
Mori A,
Imai C,
Fukuda M,
Takagi M,
Yano K,
( 1989 ) Cloning and sequencing of the gene encoding the 72-kilodalton dehydrogenase subunit of alcohol dehydrogenase from Acetobacter aceti. PMID : 2722742 : DOI : 10.1128/jb.171.6.3115-3122.1989 PMC : PMC210023 Abstract >>
A genomic library of Acetobacter aceti DNA was constructed by using a broad-host-range cosmid vector. Complementation of a spontaneous alcohol dehydrogenase-deficient mutant resulted in the isolation of a plasmid designated pAA701. Subcloning and deletion analysis of pAA701 limited the region that complemented the deficiency in alcohol dehydrogenase activity of the mutant. The nucleotide sequence of this region was determined and showed that this region contained the full structural gene for the 72-kilodalton dehydrogenase subunit of the alcohol dehydrogenase enzyme complex. The predicted amino acid sequence of the gene showed homology with sequences of methanol dehydrogenase structural genes of Paracoccus denitrificans and Methylobacterium organophilum.
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17. |
Li L,
Wieme A,
Spitaels F,
Balzarini T,
Nunes OC,
Manaia CM,
Van Landschoot A,
De Vuyst L,
Cleenwerck I,
Vandamme P,
( 2014 ) Acetobacter sicerae sp. nov., isolated from cider and kefir, and identification of species of the genus Acetobacter by dnaK, groEL and rpoB sequence analysis. PMID : 24763601 : DOI : 10.1099/ijs.0.058354-0 Abstract >>
Five acetic acid bacteria isolates, awK9_3, awK9_4 (= LMG 27543), awK9_5 (= LMG 28092), awK9_6 and awK9_9, obtained during a study of micro-organisms present in traditionally produced kefir, were grouped on the basis of their MALDI-TOF MS profile with LMG 1530 and LMG 1531(T), two strains currently classified as members of the genus Acetobacter. Phylogenetic analysis based on nearly complete 16S rRNA gene sequences as well as on concatenated partial sequences of the housekeeping genes dnaK, groEL and rpoB indicated that these isolates were representatives of a single novel species together with LMG 1530 and LMG 1531(T) in the genus Acetobacter, with Acetobacter aceti, Acetobacter nitrogenifigens, Acetobacter oeni and Acetobacter estunensis as nearest phylogenetic neighbours. Pairwise similarity of 16S rRNA gene sequences between LMG 1531(T) and the type strains of the above-mentioned species were 99.7%, 99.1%, 98.4% and 98.2%, respectively. DNA-DNA hybridizations confirmed that status, while amplified fragment length polymorphism (AFLP) and random amplified polymorphic DNA (RAPD) data indicated that LMG 1531(T), LMG 1530, LMG 27543 and LMG 28092 represent at least two different strains of the novel species. The major fatty acid of LMG 1531(T) and LMG 27543 was C18 : 1�s7c. The major ubiquinone present was Q-9 and the DNA G+C contents of LMG 1531(T) and LMG 27543 were 58.3 and 56.7 mol%, respectively. The strains were able to grow on D-fructose and D-sorbitol as a single carbon source. They were also able to grow on yeast extract with 30% D-glucose and on standard medium with pH 3.6 or containing 1% NaCl. They had a weak ability to produce acid from d-arabinose. These features enabled their differentiation from their nearest phylogenetic neighbours. The name Acetobacter sicerae sp. nov. is proposed with LMG 1531(T) (= NCIMB 8941(T)) as the type strain.
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18. |
Valera MJ,
Torija MJ,
Mas A,
Mateo E,
( 2015 ) Cellulose production and cellulose synthase gene detection in acetic acid bacteria. PMID : 25381910 : DOI : 10.1007/s00253-014-6198-1 Abstract >>
The ability of acetic acid bacteria (AAB) to produce cellulose has gained much industrial interest due to the physical and chemical characteristics of bacterial cellulose. The production of cellulose occurs in the presence of oxygen and in a glucose-containing medium, but it can also occur during vinegar elaboration by the traditional method. The vinegar biofilm produced by AAB on the air-liquid interface is primarily composed of cellulose and maintains the cells in close contact with oxygen. In this study, we screened for the ability of AAB to produce cellulose using different carbon sources in the presence or absence of ethanol. The presence of cellulose in biofilms was confirmed using the fluorochrome Calcofluor by microscopy. Moreover, the process of biofilm formation was monitored under epifluorescence microscopy using the Live/Dead BacLight Kit. A total of 77 AAB strains belonging to 35 species of Acetobacter, Komagataeibacter, Gluconacetobacter, and Gluconobacter were analysed, and 30 strains were able to produce a cellulose biofilm in at least one condition. This cellulose production was correlated with the PCR amplification of the bcsA gene that encodes cellulose synthase. A total of eight degenerated primers were designed, resulting in one primer pair that was able to detect the presence of this gene in 27 AAB strains, 26 of which formed cellulose.
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19. |
Huang CH,
Chang MT,
Huang L,
Chua WS,
( 2014 ) Molecular discrimination and identification of Acetobacter genus based on the partial heat shock protein 60 gene (hsp60) sequences. PMID : 23681743 : DOI : 10.1002/jsfa.6231 Abstract >>
To identify the Acetobacter species using phenotypic and genotypic (16S rDNA sequence analysis) technique alone is inaccurate. The aim of this study was to use the hsp60 gene as a target for species discrimination in the genus Acetobacter, as well as to develop species-specific polymerase chain reaction and mini-sequencing methods for species identification and differentiation. The average sequence similarity for the hsp60 gene (89.8%) among type strains was significantly less than that for the 16S rRNA gene (98.0%), and the most Acetobacter species could be clearly distinguished. In addition, a pair of species-specific primer was designed and used to specifically identify Acetobacter aceti, Acetobacter estunensis and Acetobacter oeni, but none of the other Acetobacter strains. Afterwards, two specific single-nucleotide polymorphism primers were designed and used to direct differentiate the strains belonging to the species A. aceti by mini-sequencing assay. The phylogenetic relationships in the Acetobacter genus can be resolved by using hsp60 gene sequencing, and the species of A. aceti can be differentiated using novel species-specific PCR combined with the mini-sequencing technology.
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20. |
Babi? M,
Rešková Z,
Bugala J,
Cimová V,
Grones P,
Grones J,
( 2014 ) The Rep20 replication initiator from the pAG20 plasmid of Acetobacter aceti. PMID : 23839792 : DOI : 10.1007/s12033-013-9680-6 Abstract >>
In the previously isolated pAG20 plasmid from the Acetobacter aceti CCM3610 strain, the Rep20 protein was characterized as a main replication initiator. The pAG20 plasmid origin was localized in the vicinity of the rep20 gene and contained two 21-nucleotide-long iteron sequences, two 13-nucleotide-long direct repeats, and a DnaA-binding site. Electrophoretic mobility shift assay and nonradioactive fragment analysis confirmed that the Rep20 protein interacted with two direct repeats (5'-TCCAAATTTGGAT'-3') and their requirement during plasmid replication was verified by mutagenesis. Although the association could not be validated of the DnaA protein of from the host cells of Escherichia coli with the plasmid-encoded replication initiator that usually occurs during replication initiation, Rep20 was able to form dimeric structures by which it could bind the sequence of the rep20 gene and autoregulate its own expression. Targeted mutagenesis of the Rep20 protein revealed the importance of the third �\-helix and ??Lys, specifically during DNA binding. The second, closely adjacent �]-sheet also took part in this process in which ??Asn played a significant role.
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21. |
Mullins EA,
Sullivan KL,
Kappock TJ,
( 2013 ) Function and X-ray crystal structure of Escherichia coli YfdE. PMID : 23935849 : DOI : 10.1371/journal.pone.0067901 PMC : PMC3720670 Abstract >>
Many food plants accumulate oxalate, which humans absorb but do not metabolize, leading to the formation of urinary stones. The commensal bacterium Oxalobacter formigenes consumes oxalate by converting it to oxalyl-CoA, which is decarboxylated by oxalyl-CoA decarboxylase (OXC). OXC and the class III CoA-transferase formyl-CoA:oxalate CoA-transferase (FCOCT) are widespread among bacteria, including many that have no apparent ability to degrade or to resist external oxalate. The EvgA acid response regulator activates transcription of the Escherichia coli yfdXWUVE operon encoding YfdW (FCOCT), YfdU (OXC), and YfdE, a class III CoA-transferase that is ~30% identical to YfdW. YfdW and YfdU are necessary and sufficient for oxalate-induced protection against a subsequent acid challenge; neither of the other genes has a known function. We report the purification, in vitro characterization, 2.1-? crystal structure, and functional assignment of YfdE. YfdE and UctC, an orthologue from the obligate aerobe Acetobacter aceti, perform the reversible conversion of acetyl-CoA and oxalate to oxalyl-CoA and acetate. The annotation of YfdE as acetyl-CoA:oxalate CoA-transferase (ACOCT) expands the scope of metabolic pathways linked to oxalate catabolism and the oxalate-induced acid tolerance response. FCOCT and ACOCT active sites contain distinctive, conserved active site loops (the glycine-rich loop and the GNxH loop, respectively) that appear to encode substrate specificity.
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22. |
Huang CH,
Chang MT,
Huang L,
Chu WS,
( 2014 ) Utilization of elongation factor Tu gene (tuf) sequencing and species-specific PCR (SS-PCR) for the molecular identification of Acetobacter species complex. PMID : 23969032 : DOI : 10.1016/j.mcp.2013.07.004 Abstract >>
The aim of this study was to use tuf gene as a molecular target for species discrimination in the Acetobacter genus, as well as to develop species-specific PCR method for direct species identification of Acetobacter aceti. The results showed that most Acetobacter species could be clearly distinguished, and the average sequence similarity for the tuf gene (89.5%) among type strains was significantly lower than that of the 16S rRNA gene sequence (98.0%). A pair of species-specific primers were designed and used to specifically identify A. aceti, but none of the other Acetobacter strains. Our data indicate that the phylogenetic relationships of most strains in the Acetobacter genus can be resolved using tuf gene sequencing, and the novel species-specific primer pair could be used to rapidly and accurately identify the species of A. aceti by the PCR based assay.
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23. |
Mullins EA,
Starks CM,
Francois JA,
Sael L,
Kihara D,
Kappock TJ,
( 2012 ) Formyl-coenzyme A (CoA):oxalate CoA-transferase from the acidophile Acetobacter aceti has a distinctive electrostatic surface and inherent acid stability. PMID : 22374910 : DOI : 10.1002/pro.2054 PMC : PMC3403466 Abstract >>
Bacterial formyl-CoA:oxalate CoA-transferase (FCOCT) and oxalyl-CoA decarboxylase work in tandem to perform a proton-consuming decarboxylation that has been suggested to have a role in generalized acid resistance. FCOCT is the product of uctB in the acidophilic acetic acid bacterium Acetobacter aceti. As expected for an acid-resistance factor, UctB remains folded at the low pH values encountered in the A. aceti cytoplasm. A comparison of crystal structures of FCOCTs and related proteins revealed few features in UctB that would distinguish it from nonacidophilic proteins and thereby account for its acid stability properties, other than a strikingly featureless electrostatic surface. The apparently neutral surface is a result of a "speckled" charge decoration, in which charged surface residues are surrounded by compensating charges but do not form salt bridges. A quantitative comparison among orthologs identified a pattern of residue substitution in UctB that may be a consequence of selection for protein stability by constant exposure to acetic acid. We suggest that this surface charge pattern, which is a distinctive feature of A. aceti proteins, creates a stabilizing electrostatic network without stiffening the protein or compromising protein-solvent interactions.
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24. |
( 1997 ) Cloning and expression of AatII restriction-modification system in Escherichia coli. PMID : 9034320 : DOI : 10.1016/s0378-1119(96)00641-5 Abstract >>
The genes encoding the AatII restriction endonuclease and methylase from Acetobacter aceti have been cloned and expressed in Escherichia coli. The nucleotide sequences of aatIIM and aatIIR genes were determined. The aatIIM and aatIIR genes are 996 bp and 1038 bp, respectively, encoding the 331-aa methylase with a predicted molecular mass of 36.9 kDa, and the 345-aa AatII restriction endonuclease with a predicted molecular mass of 38.9 kDa. The two genes overlap by 4 base pairs and are transcribed in the same orientation. The aatIIRM genes are located next to a putative gene for plasmid mobilization. A stable overproducing strain was constructed, in which the aatIIM gene was expressed from a pSC101-derived plasmid. The aatIIR gene was inserted into a modified T7 expression vector that carries transcription terminators upstream from the T7 promoter. The recombinant AatII restriction endonuclease was purified to near homogeneity by chromatography through DEAE Sepharose, Heparin Sepharose, and phosphocellulose columns.
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25. |
( 1993 ) Characterization of a cytochrome a1 that functions as a ubiquinol oxidase in Acetobacter aceti. PMID : 8392509 : DOI : 10.1128/jb.175.14.4307-4314.1993 PMC : PMC204870 Abstract >>
The terminal oxidase for ethanol oxidation in Acetobacter aceti was purified as a complex consisting of four subunits (subunits I, II, III, and IV) with molecular masses of 72, 34, 21, and 13 kDa, respectively. Spectrophotometric analysis and catalytic properties determined with the purified enzyme showed that it belonged to a family of cytochrome a1 (ba)-type ubiquinol oxidases. A polymerase chain reaction with two oligonucleotides designed for amino acid sequences that are conserved in subunit I of the aa3-type cytochrome c oxidases from various origins and of an Escherichia coli o (bo)-type ubiquinol oxidase was used for cloning the cytochrome a1 gene. A 0.5-kb fragment thus amplified was used as the probe to clone a 4.5-kb KpnI fragment that contained a putative open reading frame for the whole subunit I gene. The molecular weight and amino acid composition of the product of this open reading frame (cyaA) were the same as those of the purified protein from A. aceti. The amino acid sequence of CyaA was homologous to that of subunit I of the E. coli o-type ubiquinol oxidase. Nucleotide sequence analysis of the region neighboring the cyaA gene revealed that the genes (cyaB, cyaC, and cyaD) encoding the other three subunits (subunits II, III, and IV) were clustered upstream and downstream of the cyaA gene in the order cyaB, cyaA, cyaC, and cyaD and with the same transcription polarity, forming an operon. As expected from the enzymatic properties, CyaB, CyaC, and CyaD showed great similarity in amino acid sequence to the corresponding sununits of the E. coli o-type ubiquinol oxidase and as(3)-type cytochrome c oxidases.
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26. |
( 1993 ) Cloning and sequencing the recA+ genes of Acetobacter polyoxogenes and Acetobacter aceti: construction of recA- mutants of by transformation-mediated gene replacement. PMID : 8486287 : DOI : 10.1016/0378-1119(93)90615-a Abstract >>
The recA+ gene of Acetobacter polyoxogenes was cloned as a gene that conferred methyl methanesulfonate resistance (MMSR) on the RecA- Escherichia coli HB101. The cloned recA+ gene also conferred (i) resistance to UV irradiation, (ii) enhanced intrachromosomal recombination, and (iii) permitted prophage phi 80 induction in E. coli recA- lysogens. Nucleotide sequence determination revealed that the recA product consists of 348 amino acids (aa) corresponding to 38 kDa, and shows significant similarity to RecA proteins from other Gram- bacteria. Next, a portion of recA from Acetobacter aceti was cloned by using polymerase chain reaction with oligodeoxyribonucleotide primers design based on the A. polyoxogenes recA sequence. Due to availability of efficient host-vector and transformation systems in A. aceti, recA mutants of A. aceti were obtained by transformation-mediated gene replacement with the cloned A. aceti recA gene which was inactivated by insertion of the kanamycin-resistance-encoding gene from pACYC177. The recA mutants obtained in this way showed similar phenotypes to those of E. coli recA strains, such as increased sensitivity to MMS and to UV irradiation, and decreased homologous recombination.
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27. |
Yamano S,
Tanaka J,
Inoue T,
( 1994 ) Cloning and expression of the gene encoding alpha-acetolactate decarboxylase from Acetobacter aceti ssp. xylinum in brewer's yeast. PMID : 7764563 : Abstract >>
Acetobacter aceti ssp. xylinum genomic library was constructed using cosmid pJB8 in Escherichia coli. The gene encoding alpha-acetolactate decarboxylase (ALDC) was isolated from the library by direct measurement of ALDC activity. The ALDC gene was expressed by its own promoter in E. coli. The nucleotide sequence was determined, and an open reading frame which may encode a protein composed of 304 amino acids with a molecular weight of 33,747 was found. A brewer's yeast was transformed with the YEp-type plasmid containing the ALDC gene placed under the control of the glyceraldehyde-3-phosphate dehydrogenase promoter. The laboratory-scale growth test confirmed that the total diacetyl concentration was considerably reduced by the transformant. The analysis of the wort indicates that the Acetobacter ALDC reduces the concentration of diacetyl more effectively than that of 2,3-pentanedione.
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28. |
Cozier GE,
Giles IG,
Anthony C,
( 1995 ) The structure of the quinoprotein alcohol dehydrogenase of Acetobacter aceti modelled on that of methanol dehydrogenase from Methylobacterium extorquens. PMID : 7772016 : DOI : 10.1042/bj3080375 PMC : PMC1136936 Abstract >>
The 1.94 A structure of methanol dehydrogenase has been used to provide a model structure for part of a membrane quinohaemoprotein alcohol dehydrogenase. The basic superbarrel structure and the active-site region are retained, indicating essentially similar mechanisms of action, but there are considerable differences in the external loops, particularly those involved in formation of the shallow funnel leading to the active site.
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29. |
( 2012 ) Crystal structures of Acetobacter aceti succinyl-coenzyme A (CoA):acetate CoA-transferase reveal specificity determinants and illustrate the mechanism used by class I CoA-transferases. PMID : 23030530 : DOI : 10.1021/bi300957f Abstract >>
Coenzyme A (CoA)-transferases catalyze transthioesterification reactions involving acyl-CoA substrates, using an active-site carboxylate to form covalent acyl anhydride and CoA thioester adducts. Mechanistic studies of class I CoA-transferases suggested that acyl-CoA binding energy is used to accelerate rate-limiting acyl transfers by compressing the substrate thioester tightly against the catalytic glutamate [White, H., and Jencks, W. P. (1976) J. Biol. Chem. 251, 1688-1699]. The class I CoA-transferase succinyl-CoA:acetate CoA-transferase is an acetic acid resistance factor (AarC) with a role in a variant citric acid cycle in Acetobacter aceti. In an effort to identify residues involved in substrate recognition, X-ray crystal structures of a C-terminally His(6)-tagged form (AarCH6) were determined for several wild-type and mutant complexes, including freeze-trapped acetylglutamyl anhydride and glutamyl-CoA thioester adducts. The latter shows the acetate product bound to an auxiliary site that is required for efficient carboxylate substrate recognition. A mutant in which the catalytic glutamate was changed to an alanine crystallized in a closed complex containing dethiaacetyl-CoA, which adopts an unusual curled conformation. A model of the acetyl-CoA Michaelis complex demonstrates the compression anticipated four decades ago by Jencks and reveals that the nucleophilic glutamate is held at a near-ideal angle for attack as the thioester oxygen is forced into an oxyanion hole composed of Gly388 NH and CoA N2?. CoA is nearly immobile along its entire length during all stages of the enzyme reaction. Spatial and sequence conservation of key residues indicates that this mechanism is general among class I CoA-transferases.
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