AS2 - Word Related Documents




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52200.7122Detoxification of ars genotypes by arsenite-oxidizing bacteria through arsenic biotransformation. The detoxification process of transforming arsenite (As(III)) to arsenate (As(V)) through bacterial oxidation presents a potent approach for bioremediation of arsenic-polluted soils in abandoned mines. In this study, twelve indigenous arsenic-oxidizing bacteria (AOB) were isolated from arsenic-contaminated soils. Among these, Paenibacillus xylanexedens EBC-SK As2 (MF928871) and Ochrobactrum anthropi EBC-SK As11 (MF928880) were identified as the most effective arsenic-oxidizing isolates. Evaluations for bacterial arsenic resistance demonstrated that P. xylanexedens EBC-SK As2 (MF928871) could resist As(III) up to 40 mM, while O. anthropi EBC-SK As11 (MF928880) could resist As(III) up to 25 mM. From these bacterial strains, genotypes of arsenic resistance system (ars) were detected, encompassing ars leader genes (arsR and arsD), membrane genes (arsB and arsJ), and aox genes known to be crucial for arsenic detoxification. These ars genotypes in the isolated AOBs might play an instrumental role in arsenic-contaminated soils with potential to reduce arsenic contamination.202439382695
82310.6737Characterization of the prtA and prtB genes of Erwinia chrysanthemi EC16. Two tandem metalloprotease-encoding structural genes, prtA and prtB, were sequenced from Erwinia chrysanthemi EC16. These were highly homologous to previously reported genes from the same bacteria, as well as to three other metalloprotease-encoding genes from enteric bacteria. The three tandem prt structural genes from strain EC16 were closely linked to a cluster of genes previously found to be essential for extracellular secretion of the metalloproteases.19938224883
36220.6704Complete Genome Sequences of Highly Arsenite-Resistant Bacteria Brevibacterium sp. Strain CS2 and Micrococcus luteus AS2. The complete genome sequences of two highly arsenite-resistant Actinomycetales isolates are presented. Both genomes are G+C rich and consist of a single chromosome containing homologs of known arsenite resistance genes.201931371538
82230.6702Exoglucanase-encoding genes from three Wickerhamomyces anomalus killer strains isolated from olive brine. Wickerhamomyces anomalus killer strains are important for fighting pathogenic yeasts and for controlling harmful yeasts and bacteria in the food industry. Targeted disruption of key genes in β-glucan synthesis of a sensitive Saccharomyces cerevisiae strain conferred resistance to the toxins of W. anomalus strains BS91, BCA15 and BCU24 isolated from olive brine. Competitive inhibition of the killing activities by laminarin and pustulan refer to β-1,3- and β-1,6-glucans as the main primary toxin targets. The extracellular exoglucanase-encoding genes WaEXG1 and WaEXG2 from the three strains were sequenced and were found to display noticeable similarities to those from known potent W. anomalus killer strains.201323148020
50740.6699Tellurite resistance and reduction by obligately aerobic photosynthetic bacteria. Seven species of obligately aerobic photosynthetic bacteria of the genera Erythromicrobium, Erythrobacter, and Roseococcus demonstrated high-level resistance to tellurite and accumulation of metallic tellurium crystals. High-level resistance without tellurite reduction was observed for Roseococcus thiosulfatophilus and Erythromicrobium ezovicum grown with certain organic carbon sources, implying that tellurite reduction is not essential to confer tellurite resistance.199616535446
81150.6666Genomic analysis of five antibiotic-resistant bacteria isolated from the environment. Our study presents the whole-genome sequences and annotation of five bacteria isolates, each demonstrating distinct antibiotic resistance. These isolates include Bacillus paranthracis RIT 841, Atlantibacter hermanii RIT 842, Pantoea leporis RIT 844, Enterococcus casseliflavus RIT 845, and Pseudomonas alkylphenolica RIT 846, underscoring the importance of understanding antimicrobial resistance.202439189722
52460.6630Sulfamethoxazole degradation by Pseudomonas silesiensis F6a isolated from bioelectrochemical technology-integrated constructed wetlands. The antibiotic-degrading ability and mechanism of the bacteria in the novel and ecological bioelectrochemical technology-integrated constructed wetlands (BICW) remain unknown. In this study, the sulfamethoxazole (SMX) degrading strain Pseudomonas silesiensis F6a (F6a), which had high degradation efficiency, was firstly isolated from a substrate sample in BICW. The SMX degradation process of F6a follows pseudo first order kinetics. Four metabolic pathways and twelve degradation products were identified. Based on genomics and proteomics analysis, six key SMX-degrading genes, Gene4641 deoC, Gene0552 narI, Gene0546 luxS, Gene1753 nuoH, Gene0655 and Gene4650, were identified, which were mainly participated in C-S cleavage, S-N hydrolysis and isoxazole ring cleavage. Interestingly, we found the corresponding sulfonamides resistance genes were not detected in F6a, which may provide an evidence for low abundance of the sulfonamides resistance genes in BICW system. These findings would contribute to a better understanding of biotransformation of antibiotic in the BICW.202235636241
52870.6627Effect of dimethyl sulphoxide on the expression of nitrogen fixation in bacteria. Storage in dimethyl sulphoxide (DMSO) of Escherichia coli K12 hybrids carrying nif+ genes from Klebsiella pneumoniae can result in selection of a defective nitrogen-fixing phenotype. Similar results are obtained with E. coli K12 hybrids containing the nitrogen-fixing capacity from Rhizobium trifolii. DMSO appears to affect particular inner membrane proteins associated with energy metabolism in E. coli K12 and four chromosomal regions (chlD, chlG, his and unc) are associated with resistance to DMSO.1977332135
614680.6624Arsenic resistance genes of As-resistant purple nonsulfur bacteria isolated from As-contaminated sites for bioremediation application. This study aimed to identify arsenic resistant mechanisms in As-resistant purple nonsulfur bacteria (PNSB) by screening them for presence of As-resistance genes and related enzymes. Resistance to As(III) and As(V) of four As-resistant PNSB determined in terms of median inhibition concentration (IC(50) values) were in the order of strains Rhodopseudomonas palustris C1 > R. palustris AB3 > Rubrivivax benzoatilyticus C31 > R. palustris L28 which corresponded to the presence of As-resistance genes in these bacteria. The strain C1 showed all As-marker genes; arsC, arsM, aioA, and acr3, while aioA was not detected in strain AB3. Strains C31 and L28 had only Arsenite-transporter gene, acr3. Translation of all these detected gene sequences of strain C1 to amino acid sequences showed that these proteins have vicinal cysteine; Cys126, Cys105, and Cys178 of Acr3, ArsC, AioA, respectively. Tertiary structure of proteins Acr3, ArsC, AioA, and ArsM showed strain C1 exhibits the high activities of arsenite oxidase and arsenate reductase enzymes that are encoded by aioA and arsC genes, respectively. Moreover, strain C1 with arsM gene produced volatile-methylated As-compounds; monomethylarsonic acid (MMA), dimethylarsenic acid (DMA), and arsenobetaine (AsB) in the presence of either As(III) or As(V). In conclusion, the strain C1 has great potential for its application in bioremediation of As-contaminated sites.201728054716
53390.6619Construction of broad-host-range cosmid cloning vectors: identification of genes necessary for growth of Methylobacterium organophilum on methanol. Four new cloning vectors have been constructed from the broad-host-range cloning vector pRK290. These vectors, pLA2901, pLA2905, pLA2910, and pLA2917, confer resistance to kanamycin and tetracycline. The latter two are cosmid derivatives of pLA2901. The new vectors can be mobilized into, and are stably maintained in, a variety of gram-negative bacteria. A Sau3A genomic bank of Methylobacterium organophilum strain xx DNA has been constructed in pLA2917, and complementation analysis, with a variety of mutants unable to grow on methanol, revealed at least five separate regions necessary for growth on methanol. Complementation analysis and Tn5 mutagenesis data suggest that at least three genes are responsible for expression of active methanol dehydrogenase.19852982796
534100.6615Plasmid shuttle vector with two insertionally inactivable markers for coryneform bacteria. A new shuttle vector pCEM500 replicating in Escherichia coli and in Brevibacterium flavum was constructed. It carries two antibiotic resistance determinants (Kmr/Gmr from plasmid pSa of Gram-negative bacteria and Smr/Spr from plasmid pCG4 of Corynebacterium glutamicum) which are efficiently expressed in both hosts and can be inactivated by insertion of DNA fragments into the unique restriction endonuclease sites located within them. This vector was found to be stably maintained in B. flavum and can be used for transfer of the cloned genes into this amino-acid-producing coryneform bacterium.19902148164
3062110.6614Characterization of organotin-resistant bacteria from boston harbor sediments. Organotins are widely used in agriculture and industry. They are toxic to a variety of organisms including bacteria, although little is known of their physiology and ecology. Bacteria resistant to six organotins-tributyltin (TBT), dibutyltin (DBT), monobutyltin (MBT), triphenyltin (TPT), diphenyltin (DPT), and monophenyltin (MPT)-were isolated from Boston Harbor sediments, Massachusetts, USA. Bacteria resistant to each of the organotins, except DPT, were isolated directly from estuarine sediments. Viability of the organotin-resistant bacteria on serial transfer in the laboratory ranged from 80 to 91%. Each isolate was screened for resistance to the other organotins. All of 250 isolates were resistant to at least two organotins. No DPT-resistant isolates were found on initial isolation on DPT, although there was DPT resistance among the other organotin-resistant bacteria. Eighty percent of TBT-resistant bacteria were TPT-resistant, suggesting that antifouling paints containing TPT will not be a suitable substitute for TBT in paints designed to inhibit microbial biofilms. Debutylation reduced toxicity in some cases while dephenylation did not. Thus, even though trisubstituted organotins are generally believed to be more toxic than di- or monosubstituted organotins, this may not always be the case, and more than one mechanism of resistance may be involved. All the bacteria were resistant to at least six of eight heavy metals tested, suggesting that resistance to heavy metals may be associated with resistance to organotins.19989732471
6150120.6610Redox biotransformation of arsenic along with plant growth promotion by multi-metal resistance Pseudomonas sp. MX6. Remediation of toxic metal-polluted sites by microorganisms is an environment-friendly remediation technique. Multi-metal-resistant bacteria were isolated from a wastewater treatment plant showing resistance against As(III), As(V), Cr, Co, Cu, Cd, Hg, Ni, Pb, Se and Zn. Maximum resistance against all metals was shown by the bacterial isolate MX-6 (As 20mM, Cd 30mM, Cr 5.0mM, Co 25mM, Cu 25mM, Ni 20mM, Zn 30mM, Pb 15mM, Se 20mM and Hg 2.5mM), which was identified as Pseudomonas sp. through 16S rDNA sequencing. Pseudomonas sp. MX-6 reduced 506μM As(V) and also oxidized 160μM As(III). The genes for As, Cd, Se and Zn resistance in Pseudomonas sp. MX-6 were found to be plasmid borne, as indicated by transformation. Pseudomonas sp. MX-6 produced 49.37μg·mL(-1) IAA and was also positive for HCN production and phosphate solubilisation. The bacterial isolate also supported Vigna radiata growth, both in the absence and presence of the aforementioned metals. Such bacteria can be used as biofertilizers to reclaim the polluted lands and to enhance crop production in metal-contaminated soils.201728684222
3738130.6610In Silico Prediction of Antibiotic Resistance in Mycobacterium ulcerans Agy99 through Whole Genome Sequence Analysis. Buruli ulcer is an emerging infectious disease caused by Mycobacterium ulcerans that has been reported from 33 countries. Antimicrobial agents either alone or in combination with surgery have been proved to be clinically relevant and therapeutic strategies have been deduced mainly from the empirical experience. The genome sequences of M. ulcerans strain AGY99, M. ulcerans ecovar liflandii, and three Mycobacterium marinum strains were analyzed to predict resistance in these bacteria. Fourteen putative antibiotic resistance genes from different antibiotics classes were predicted in M. ulcerans and mutation in katG (R431G) and pncA (T47A, V125I) genes were detected, that confer resistance to isoniazid and pyrazinamide, respectively. No mutations were detected in rpoB, gyrA, gyrB, rpsL, rrs, emb, ethA, 23S ribosomal RNA genes and promoter region of inhA and ahpC genes associated with resistance. Our results reemphasize the usefulness of in silico analysis for the prediction of antibiotic resistance in fastidious bacteria.201728749770
530140.6610Location of the genes for anthranilate synthase in Streptomyces venezuelae ISP5230: genetic mapping after integration of the cloned genes. The anthranilate synthase (trpEG) genes in Streptomyces venezuelae ISP5230 were located by allowing a segregationally unstable plasmid carrying cloned S. venezuelae trpEG DNA and a thiostrepton resistance (tsr) marker to integrate into the chromosome. The integrated tsr was mapped by conjugation and transduction to a location close to tyr-2, between arg-6 and trpA13. A genomic DNA fragment containing trpC from S. venezuelae ISP5230 was cloned by complementation of a trpC mutation in Streptomyces lividans. Evidence from restriction enzyme analysis of the cloned DNA fragments, from Southern hybridization using the cloned trp DNA as probes, and from cotransduction frequencies, placed trpEG at a distance of 12-45 kb from the trpCBA cluster. The overall arrangement of tryptophan biosynthesis genes in the S. venezuelae chromosome differs from that in other bacteria examined so far.19938515229
527150.6606Characterization of the bagremycin biosynthetic gene cluster in Streptomyces sp. Tü 4128. Bagremycin A and bagremycin B isolated from Streptomyces sp. Tü 4128 have activities against Gram-positive bacteria, fungi and also have a weak antitumor activity, which make them have great potential for development of novel antibiotics. Here, we report a draft genome 8,424,112 bp in length of S. sp. Tü 4128 by Illumina Hiseq2000, and identify the bagremycins biosynthetic gene cluster (BGC) by bioinformatics analysis. The putative bagremycins BGC includes 16 open reading frames (ORFs) with the functions of biosynthesis, resistance and regulation. Disruptions of relative genes and HPLC analysis of bagremycins production demonstrated that not all the genes within the BGC are responsible for the biosynthesis of bagremycins. In addition, the biosynthetic pathways of bagremycins are proposed for deeper inquiries into their intriguing biosynthetic mechanism.201930526412
5212160.6606Draft Genome Sequences of Pseudomonas MWU13-2625 and MWU12-2115, Isolated from a Wild Cranberry Bog at the Cape Cod National Seashore. Two highly similar Pseudomonas sp. genome sequences from wetland bog soil isolates with draft genomes of ~6.3 Mbp are reported. Although the exact taxonomic placement and environmental roles of these bacteria are unclear, predicted genes for stress tolerance, antibiotic resistance, and a type VI secretion system were detected.201830533670
332170.6605Analysis and Reconstitution of the Menaquinone Biosynthesis Pathway in Lactiplantibacillus plantarum and Lentilactibacillus buchneri. In Lactococcus lactis and some other lactic acid bacteria, respiratory metabolism has been reported upon supplementation with only heme, leading to enhanced biomass formation, reduced acidification, resistance to oxygen, and improved long-term storage. Genes encoding a complete respiratory chain with all components were found in genomes of L. lactis and Leuconostoc mesenteroides, but menaquinone biosynthesis was found to be incomplete in Lactobacillaceae (except L. mesenteroides). Lactiplantibacillus plantarum has only two genes (menA, menG) encoding enzymes in the biosynthetic pathway (out of eight), and Lentilactobacillus buchneri has only four (menA, menB, menE, and menG). We constructed knock-out strains of L. lactis defective in menA, menB, menE, and menG (encoding the last steps in the pathway) and complemented these by expression of the extant genes from Lactipl. plantarum and Lent. buchneri to verify their functionality. Three of the Lactipl. plantarum biosynthesis genes, lpmenA1, lpmenG1, and lpmenG2, as well as lbmenB and lbmenG from Lent. buchneri, reconstituted menaquinone production and respiratory growth in the deficient L. lactis strains when supplemented with heme. We then reconstituted the incomplete menaquinone biosynthesis pathway in Lactipl. plantarum by expressing six genes from L. lactis homologous to the missing genes in a synthetic operon with two inducible promoters. Higher biomass formation was observed in Lactipl. plantarum carrying this operon, with an OD(600) increase from 3.0 to 5.0 upon induction.202134361912
812180.6603Characterization of plQ5 plasmid originating fromKlebsiella pneumoniae. plQ5 plasmid consists of a group of genes specifying resistance to ampicillin, chloramphenicol, carbencillin, kanamycin and trimethoprim-sulphamethoxazole. It is isolated inKlebslella pneumoniae ZD532, is about 26.8 Kb and is freely transmissible to various bacterial species of Gram-negative bacteria. Physical characterization revealed that plQ5 plasmid has a single site forHindill,BamHI,EcoRI and two sites forBglII restriction enzyme.199024429982
366190.6602Genes encoding mercuric reductases from selected gram-negative aquatic bacteria have a low degree of homology with merA of transposon Tn501. An investigation of the Hg2+ resistance mechanism of four freshwater and four coastal marine bacteria that did not hybridize with a mer operonic probe was conducted (T. Barkay, C. Liebert, and M. Gillman, Appl. Environ. Microbiol. 55:1196-1202, 1989). Hybridization with a merA probe, the gene encoding the mercuric reductase polypeptide, at a stringency of hybridization permitting hybrid formation between evolutionarily distant merA genes (as exists between gram-positive and -negative bacteria), detected merA sequences in the genomes of all tested strains. Inducible Hg2+ volatilization was demonstrated for all eight organisms, and NADPH-dependent mercuric reductase activities were detected in crude cell extracts of six of the strains. Because these strains represented random selections of bacteria from three aquatic environments, it is concluded that merA encodes a common molecular mechanism for Hg2+ resistance and volatilization in aerobic heterotrophic aquatic communities.19902166470