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interactions of non-natural halogenated substrates with d-specific dehalogenase (dehd) mutants using in silico studies.the d-2-haloacid dehalogenase of d-specific dehalogenase (dehd) from rhizobium sp. rc1 catalyses the hydrolytic dehalogenation of d-haloalkanoic acids, inverting the substrate-product configuration and thereby forming the corresponding l-hydroxyalkanoic acids. our investigations were focused on dehd mutants: r134a and y135a. we examined the possible interactions between these mutants with haloalkanoic acids and characterized the key catalytic residues in the wild-type dehalogenase, to design deh ...201426019583
water quality assessment of aquatic ecosystems using ecological criteria - case study in bulgaria.four aquatic ecosystems (two rivers and two dams) situated in the western part of bulgaria were investigated over a three years' period. the river egulya and petrohan dam are situated in mountainous regions at about 1000 m altitude, and are not influenced by any anthropogenic sources. petrohan dam is a site for long-term ecosystem research as a part of bulgarian long-term ecological research network. the other two systems belong to populated industrial areas. the river martinovska flows through ...201426019591
research into acetone removal from air by biofiltration using a biofilter with straight structure plates.the biological air treatment method is based on the biological destruction of organic compounds using certain cultures of microorganisms. this method is simple and may be applied in many branches of industry. the main element of biological air treatment devices is a filter charge. tests were carried out using a new-generation laboratory air purifier with a plate structure. this purifier is called biofilter. the biofilter has a special system for packing material humidification which does not req ...201526019659
high-throughput screening for a moderately halophilic phenol-degrading strain and its salt tolerance response.a high-throughput screening system for moderately halophilic phenol-degrading bacteria from various habitats was developed to replace the conventional strain screening owing to its high efficiency. bacterial enrichments were cultivated in 48 deep well microplates instead of shake flasks or tubes. measurement of phenol concentrations was performed in 96-well microplates instead of using the conventional spectrophotometric method or high-performance liquid chromatography (hplc). the high-throughpu ...201526020478
pseudomonas putida and pseudomonas fluorescens species group recovery from human homes varies seasonally and by environment.by shedding light on variation in time as well as in space, long-term biogeographic studies can help us define organisms' distribution patterns and understand their underlying drivers. here we examine distributions of pseudomonas in and around 15 human homes, focusing on the p. putida and p. fluorescens species groups. we describe recovery from 10,941 samples collected during up to 8 visits per home, occurring on average 2.6 times per year. we collected a mean of 141 samples per visit, from site ...201526023929
the wrky45-dependent signaling pathway is required for resistance against striga hermonthica parasitism.the root hemiparasite witchweed (striga spp.) is a devastating agricultural pest that causes losses of up to $1 billion us annually in sub-saharan africa. development of resistant crops is one of the cost-effective ways to address this problem. however, the molecular mechanisms underlying resistance are not well understood. to understand molecular events upon striga spp. infection, we conducted genome-scale rna sequencing expression analysis using striga hermonthica-infected rice (oryza sativa) ...201526025049
structural and mechanistic insights into the pseudomonas fluorescens 2-nitrobenzoate 2-nitroreductase nbaa.the bacterial 2-nitroreductase nbaa is the primary enzyme initiating the degradation of 2-nitrobenzoate (2-nba), and its activity is controlled by posttranslational modifications. to date, the structure of nbaa remains to be elucidated. in this study, the crystal structure of a cys194ala nbaa mutant was determined to a 1.7-å resolution. the substrate analog 2-nba methyl ester was used to decipher the substrate binding site by inhibition of the wild-type nbaa protein. tandem mass spectrometry sho ...201526025888
living in an extremely polluted environment: clues from the genome of melanin-producing aeromonas salmonicida subsp. pectinolytica 34melt.aeromonas salmonicida subsp. pectinolytica 34mel(t) can be considered an extremophile due to the characteristics of the heavily polluted river from which it was isolated. while four subspecies of a. salmonicida are known fish pathogens, 34mel(t) belongs to the only subspecies isolated solely from the environment. genome analysis revealed a high metabolic versatility, the capability to cope with diverse stress agents, and the lack of several virulence factors found in pathogenic aeromonas. the mo ...201526025898
genes associated with desiccation and osmotic stress in listeria monocytogenes as revealed by insertional mutagenesis.listeria monocytogenes is a foodborne pathogen whose survival in food processing environments may be associated with its tolerance to desiccation. to probe the molecular mechanisms used by this bacterium to adapt to desiccation stress, a transposon library of 11,700 l. monocytogenes mutants was screened, using a microplate assay, for strains displaying increased or decreased desiccation survival (43% relative humidity, 15°c) in tryptic soy broth (tsb). the desiccation phenotypes of selected muta ...201526025900
phenotypic heterogeneity, a phenomenon that may explain why quorum sensing does not always result in truly homogenous cell behavior.phenotypic heterogeneity describes the occurrence of "nonconformist" cells within an isogenic population. the nonconformists show an expression profile partially different from that of the remainder of the population. phenotypic heterogeneity affects many aspects of the different bacterial lifestyles, and it is assumed that it increases bacterial fitness and the chances for survival of the whole population or smaller subpopulations in unfavorable environments. well-known examples for phenotypic ...201526025903
dna microarray-based identification of genes regulated by ntrc in bradyrhizobium japonicum.the bradyrhizobium japonicum ntrbc two-component system is a critical regulator of cellular nitrogen metabolism, including the acquisition and catabolism of nitrogenous compounds. to better define the roles of this system, genome-wide transcriptional profiling was performed to identify the ntrc regulon during the response to nitrogen limitation. upon cells perceiving low intracellular nitrogen, they stimulate the phosphorylation of ntrc, which induces genes responsible for alteration of the core ...201526025905
[oil biodegradation by microbial-plant associations].the degradation of petroleum hydrocarbons by plant-microbial associations, as well as the peculiarities of the interaction between microorganisms in consortium and the associated plants, have been studied. it was shown that degrader microorganisms that are part of the consortium rhodococcus erythropolis s26, acinetobacter baumannii 1 b, acinetobacter baumannii 7, and pseudomonas putida f701 were effective in the degradation of oil and were good colonizers of plant roots (barley). the efficiency ...201526027354
[the role of mineral phosphorus compounds in naphthalene biodegradation by pseudomonas putida].the effect of phosphate concentration in the culture medium on the growth and naphthalene degradation by pseudomonas putida bs 3701 was studied. the limiting concentration of phosphate was 0.4 mm and 0.1 mm under cultivation in media with naphthalene and glucose, respectively the phosphate deficiency correlated with a decrease in the activities of naphthalene dioxygenase and salicylate hydroxylase and with salicylate accumulation in the culture medium. we suggest that this fact indicates the imp ...201526027355
identification of metabolism pathways directly regulated by sigma(54) factor in bacillus thuringiensis.sigma(54) (σ(54)) regulates nitrogen and carbon utilization in bacteria. promoters that are σ(54)-dependent are highly conserved and contain short sequences located at the -24 and -12 positions upstream of the transcription initiation site. σ(54) requires regulatory proteins known as bacterial enhancer-binding proteins (bebps) to activate gene transcription. we show that σ(54) regulates the capacity to grow on various nitrogen sources using a bacillus thuringiensis hd73 mutant lacking the sigl g ...201526029175
marine systems biology. 201526029243
stenotrophomonas maltophilia responds to exogenous ahl signals through the luxr solo smor (smlt1839).quorum sensing (qs) mediated by acyl homoserine lactone (ahl) molecules are probably the most widespread and studied among gram-negative bacteria. canonical ahl systems are composed by a synthase (luxi family) and a regulator element (luxr family), whose genes are usually adjacent in the genome. however, incomplete ahl-qs machinery lacking the synthase luxi is frequently observed in proteobacteria, and the regulator element is then referred as luxr solo. it has been shown that certain luxr solos ...201526029670
review of micro/nanotechnologies for microbial biosensors.a microbial biosensor is an analytical device with a biologically integrated transducer that generates a measurable signal indicating the analyte concentration. this method is ideally suited for the analysis of extracellular chemicals and the environment, and for metabolic sensory regulation. although microbial biosensors show promise for application in various detection fields, some limitations still remain such as poor selectivity, low sensitivity, and impractical portability. to overcome such ...201526029689
structural and kinetic characterization of recombinant 2-hydroxymuconate semialdehyde dehydrogenase from pseudomonas putida g7.the first enzyme in the oxalocrotonate branch of the naphthalene-degradation lower pathway in pseudomonas putida g7 is nahi, a 2-hydroxymuconate semialdehyde dehydrogenase which converts 2-hydroxymuconate semialdehyde to 2-hydroxymuconate in the presence of nad(+). nahi is in family 8 (aldh8) of the nad(p)(+)-dependent aldehyde dehydrogenase superfamily. in this work, we report the cloning, expression, purification and preliminary structural and kinetic characterization of the recombinant nahi. ...201526032336
biocompatibility of low molecular weight polymers for two-phase partitioning bioreactors.two phase partitioning bioreactors (tppbs) improve the efficiency of fermentative processes by limiting the exposure of microorganisms to toxic solutes by sequestering them into a non-aqueous phase (nap). a potential limitation of this technology, when using immiscible organic solvents as the nap, is the cytoxicity that these materials may exert on the microbes. an improved tppb configuration is one in which polymeric naps are used to replace organic solvents in order to take advantage of their ...201526032439
variation in bacterial atp concentration during rapid changes in extracellular ph and implications for the activity of attached bacteria.in this study we investigated the relationship between a rapid change in extracellular ph and the alteration of bacterial atp concentration. this relationship is a key component of a hypothesis indicating that bacterial bioenergetics - the creation of atp from adp via a proton gradient across the cytoplasmic membrane - can be altered by the physiochemical charge-regulation effect, which results in a ph shift at the bacteria's surface upon adhesion to another surface. the bacterial atp concentrat ...201526037699
comparative study of the fungicide benomyl toxicity on some plant growth promoting bacteria and some fungi in pure cultures.six laboratory experiments were carried out to investigate the effect of the fungicide benomyl on pure cultures of some plant growth promoting bacteria (pgpb) and some fungi. the highest ld50 was recorded for bacillus circulans and proved to be the most resistant to the fungicide, followed by azospirillum braziliense, while penicillium sp. was the most affected microorganism. ld50 values for the affected microorganisms were in 21-240 orders of magnitude lower in comparison with the ld50 value fo ...201426038670
the design of simple bacterial microarrays: development towards immobilizing single living bacteria on predefined micro-sized spots on patterned surfaces.in this paper we demonstrate a procedure for preparing bacterial arrays that is fast, easy, and applicable in a standard molecular biology laboratory. microcontact printing is used to deposit chemicals promoting bacterial adherence in predefined positions on glass surfaces coated with polymers known for their resistance to bacterial adhesion. highly ordered arrays of immobilized bacteria were obtained using microcontact printed islands of polydopamine (pd) on glass surfaces coated with the antia ...201526039378
surface mn(ii) oxidation actuated by a multicopper oxidase in a soil bacterium leads to the formation of manganese oxide minerals.in this manuscript, we report that a bacterial multicopper oxidase (mco266) catalyzes mn(ii) oxidation on the cell surface, resulting in the surface deposition of mn(iii) and mn(iv) oxides and the gradual formation of bulky oxide aggregates. these aggregates serve as nucleation centers for the formation of mn oxide micronodules and mn-rich sediments. a soil-borne escherichia coli with high mn(ii)-oxidizing activity formed mn(iii)/mn(iv) oxide deposit layers and aggregates under laboratory cultur ...201526039669
two decades of warming increases diversity of a potentially lignolytic bacterial community.as earth's climate warms, the massive stores of carbon found in soil are predicted to become depleted, and leave behind a smaller carbon pool that is less accessible to microbes. at a long-term forest soil-warming experiment in central massachusetts, soil respiration and bacterial diversity have increased, while fungal biomass and microbially-accessible soil carbon have decreased. here, we evaluate how warming has affected the microbial community's capability to degrade chemically-complex soil c ...201526042112
a quick rhizobacterial selection tests for the remediation of copper contaminated soils.the main objective of the study is to develop and improve quick bacterial tests to select the best candidates for the bioaugmentation of metal-contaminated soil, coupled with phytoextraction.201526042640
draft genome sequence of hydrocarbon-degrading pseudomonas putida strain kg-4, isolated from soil samples collected from krishna-godavari basin in india.we report here the 5.58-mb draft genome of pseudomonas putida strain kg-4 obtained from the oil fields of the krishna-godavari basin, andhra pradesh, india. the genome sequence is expected to facilitate identification and understanding of genes associated with hydrocarbon metabolism, which can help in developing strategies for managing oil spills and bioremediation.201526044433
identification of a chemoreceptor for c2 and c3 carboxylic acids.chemoreceptors are at the beginnings of chemosensory signaling cascades that mediate chemotaxis. most bacterial chemoreceptors are functionally unannotated and are characterized by a diversity in the structure of their ligand binding domains (lbds). the data available indicate that there are two major chemoreceptor families at the functional level, namely, those that respond to amino acids or to krebs cycle intermediates. since pseudomonads show chemotaxis to many different compounds and possess ...201526048936
catalytic and hydrodynamic properties of styrene monooxygenases from rhodococcus opacus 1cp are modulated by cofactor binding.styrene monooxygenases (smos) are flavoenzymes catalyzing the epoxidation of styrene into styrene oxide. smos are composed of a monooxygenase (stya) and a reductase (styb). the latter delivers reduced fad to stya on the expense of nadh. we identified rhodococcus opacus 1cp as the first microorganism to possess three different stya isoforms occurring in two systems stya1/stya2b and stya/styb, respectively. the hydrodynamic properties of stya isozymes were found to be modulated by the binding of t ...201526054733
bacterial signal transduction by cyclic di-gmp and other nucleotide second messengers.the first international symposium on c-di-gmp signaling in bacteria (22 to 25 march 2015, harnack-haus, berlin, germany)brought together 131 molecular microbiologists from 17 countries to discuss recent progress in our knowledge of bacterial nucleotide second messenger signaling. while the focus was on signal input, synthesis, degradation, and the striking diversity of the modes of action of the current second messenger paradigm, i.e., cyclic di-gmp (c-di-gmp), “classics” like camp and (p)ppgpp ...201526055111
bacterial signal transduction by cyclic di-gmp and other nucleotide second messengers.the first international symposium on c-di-gmp signaling in bacteria (22 to 25 march 2015, harnack-haus, berlin, germany)brought together 131 molecular microbiologists from 17 countries to discuss recent progress in our knowledge of bacterial nucleotide second messenger signaling. while the focus was on signal input, synthesis, degradation, and the striking diversity of the modes of action of the current second messenger paradigm, i.e., cyclic di-gmp (c-di-gmp), “classics” like camp and (p)ppgpp ...201526055111
diversity of cyclic di-gmp-binding proteins and mechanisms.cyclic di-gmp (c-di-gmp) synthetases and hydrolases (ggdef, eal, and hd-gyp domains) can be readily identified in bacterial genome sequences by using standard bioinformatic tools. in contrast, identification of c-di-gmp receptors remains a difficult task, and the current list of experimentally characterized c-di-gmp-binding proteins is likely incomplete. several classes of c-di-gmp-binding proteins have been structurally characterized; for some others, the binding sites have been identified; and ...201526055114
diversity of cyclic di-gmp-binding proteins and mechanisms.cyclic di-gmp (c-di-gmp) synthetases and hydrolases (ggdef, eal, and hd-gyp domains) can be readily identified in bacterial genome sequences by using standard bioinformatic tools. in contrast, identification of c-di-gmp receptors remains a difficult task, and the current list of experimentally characterized c-di-gmp-binding proteins is likely incomplete. several classes of c-di-gmp-binding proteins have been structurally characterized; for some others, the binding sites have been identified; and ...201526055114
functional characterization of salicylate hydroxylase from the fungal endophyte epichloë festucae.epichloë spp. are symbiotic fungal endophytes of many cool season grasses. the presence of the fungal endophytes often confers insect, drought, and disease tolerance to the host grasses. the presence of the fungal endophytes within the host plants does not elicit host defense responses. the molecular basis for this phenomenon is not known. epichloë festucae, the endophyte of festuca rubra, expresses a salicylate hydroxylase similar to nahg from the bacterium pseudomonas putida. few fungal salicy ...201526055188
artificial de novo biosynthesis of hydroxystyrene derivatives in a tyrosine overproducing escherichia coli strain.styrene and its derivatives as monomers and petroleum-based feedstocks are valuable as raw materials in industrial processes. the chemical reaction for styrene production uses harsh reaction conditions such as high temperatures or pressures, or requires base catalysis with microwave heating. on the other hand, production of styrene and its derivatives in escherichia coli is an environmental friendly process to produce conventional petroleum-based feedstocks.201526055892
extraordinary solute-stress tolerance contributes to the environmental tenacity of mycobacteria.mycobacteria are associated with a number of well-characterized diseases, yet we know little about their stress biology in natural ecosystems. this study focuses on the isolation and characterization of strains from yellowstone national park (ynp) and glacier national park (gnp; usa), the majority of those identified were mycobacterium parascrofulaceum, mycobacterium avium (ynp) or mycobacterium gordonae (gnp). generally, their windows for growth spanned a temperature range of > 60 °c; selected ...201526059202
efflux pump-deficient mutants as a platform to search for microbes that produce antibiotics.pseudomonas putida dot-t1e-18 is a strain deficient in the major antibiotic efflux pump (ttgabc) that exhibits an overall increased susceptibility to a wide range of drugs when compared with the wild-type strain. we used this strain as a platform to search for microbes able to produce antibiotics that inhibit growth. a collection of 2400 isolates from soil, sediments and water was generated and a drop assay developed to identify, via growth inhibition halos, strains that prevent the growth of do ...201526059350
activation of pathogenesis-related genes by the rhizobacterium, bacillus sp. js, which induces systemic resistance in tobacco plants.plant growth promoting rhizobacteria (pgpr) are known to confer disease resistance to plants. bacillus sp. js demonstrated antifungal activities against five fungal pathogens in in vitro assays. to verify whether the volatiles of bacillus sp. js confer disease resistance, tobacco leaves pre-treated with the volatiles were damaged by the fungal pathogen, rhizoctonia solani and oomycete phytophthora nicotianae. pre-treated tobacco leaves had smaller lesion than the control plant leaves. in pathoge ...201526060440
effects of nacl concentration on anode microbes in microbial fuel cells.understanding of how operational parameters affect the composition of exoelectrogenic microbes is an important step in the development of efficient microbial fuel cells (mfcs). in the present study, single-chamber mfcs were inoculated with rice paddy-field soil and continuously supplied with an acetate medium containing different concentrations of nacl (0-1.8 m). polarization analyses showed that power output increased as the nacl concentration increased to 0.1 m, while it was markedly diminishe ...201526061773
challenges and opportunities for customizing polyhydroxyalkanoates.polyhydroxyalkanoates (phas) as an alternative to synthetic plastics have been gaining increasing attention. being natural in their origin, phas are completely biodegradable and eco-friendly. however, consistent efforts to exploit this biopolymer over the last few decades have not been able to pull phas out of their nascent stage, inspite of being the favorite of the commercial world. the major limitations are: (1) the high production cost, which is due to the high cost of the feed and (2) poor ...201526063933
occurrence of multidrug resistant extended spectrum beta-lactamase-producing bacteria on iceberg lettuce retailed for human consumption.antibiotic resistance in bacteria is a global problem exacerbated by the dissemination of resistant bacteria via uncooked food, such as green leafy vegetables. new strains of bacteria are emerging on a daily basis with novel expanded antibiotic resistance profiles. in this pilot study, we examined the occurrence of antibiotic resistant bacteria against five classes of antibiotics on iceberg lettuce retailed in local convenience stores in rochester, michigan. in this study, 138 morphologically di ...201526064922
complete genome sequence of the cyanogenic phosphate-solubilizing pseudomonas sp. strain ccos 191, a close relative of pseudomonas mosselii.we sequenced the complete genome of the isolate pseudomonas sp. ccos 191. this strain is able to dissolve phosphate minerals and form cyanide. the genome sequence is used to establish the phylogenetic relationship of this species.201526067963
draft genome sequence of the bacterium pseudomonas putida cbb5, which can utilize caffeine as a sole carbon and nitrogen source.pseudomonas putida cbb5 was isolated from soil by enriching for growth on caffeine (1,3,7-trimethylxanthine). the draft genome of this strain is 6.9 mb, with 5,941 predicted coding sequences. it includes the previously studied alx gene cluster encoding alkylxanthine n-demethylase enzymes and other genes that enable the degradation of purine alkaloids.201526067973
identification of a specific maleate hydratase in the direct hydrolysis route of the gentisate pathway.in contrast to the well-characterized and more common maleylpyruvate isomerization route of the gentisate pathway, the direct hydrolysis route occurs rarely and remains unsolved. in pseudomonas alcaligenes ncimb 9867, two gene clusters, xln and hbz, were previously proposed to be involved in gentisate catabolism, and hbzf was characterized as a maleylpyruvate hydrolase converting maleylpyruvate to maleate and pyruvate. however, the complete degradation pathway of gentisate through direct hydroly ...201526070679
finding optimal interaction interface alignments between biological complexes.biological molecules perform their functions through interactions with other molecules. structure alignment of interaction interfaces between biological complexes is an indispensable step in detecting their structural similarities, which are key s: to understanding their evolutionary histories and functions. although various structure alignment methods have been developed to successfully access the similarities of protein structures or certain types of interaction interfaces, existing alignment ...201526072475
strategies and approaches in plasmidome studies-uncovering plasmid diversity disregarding of linear elements?the term plasmid was originally coined for circular, extrachromosomal genetic elements. today, plasmids are widely recognized not only as important factors facilitating genome restructuring but also as vehicles for the dissemination of beneficial characters within bacterial communities. plasmid diversity has been uncovered by means of culture-dependent or -independent approaches, such as endogenous or exogenous plasmid isolation as well as pcr-based detection or transposon-aided capture, respect ...201526074886
bacterial cellulose biosynthesis: diversity of operons, subunits, products, and functions.recent studies of bacterial cellulose biosynthesis, including structural characterization of a functional cellulose synthase complex, provided the first mechanistic insight into this fascinating process. in most studied bacteria, just two subunits, bcsa and bcsb, are necessary and sufficient for the formation of the polysaccharide chain in vitro. other subunits - which differ among various taxa - affect the enzymatic activity and product yield in vivo by modulating (i) the expression of the bios ...201526077867
markers of oxidative stress and neuroprogression in depression disorder.major depression is multifactorial disorder with high prevalence and alarming prognostic in the nearest 15 years. several mechanisms of depression are known. neurotransmitters imbalance and imbalance between neuroprogressive and neuroprotective factors are observed in major depression. depression is accompanied by inflammatory responses of the organism and consequent elevation of proinflammatory cytokines and increased lipid peroxidation are described in literature. neuropsychiatric disorders in ...201526078821
a macrophage subversion factor is shared by intracellular and extracellular pathogens.pathogenic bacteria have developed strategies to adapt to host environment and resist host immune response. several intracellular bacterial pathogens, including salmonella enterica and mycobacterium tuberculosis, share the horizontally-acquired mgtc virulence factor that is important for multiplication inside macrophages. mgtc is also found in pathogenic pseudomonas species. here we investigate for the first time the role of mgtc in the virulence of an extracellular pathogen, pseudomonas aerugin ...201526080006
second international meeting of isev 2013: boston, usa, april 17(th)-20(th), 2013. 201326082317
characterizations of two bacterial persulfide dioxygenases of the metallo-β-lactamase superfamily.persulfide dioxygenases (pdos), also known as sulfur dioxygenases (sdos), oxidize glutathione persulfide (gssh) to sulfite and gsh. pdos belong to the metallo-β-lactamase superfamily and play critical roles in animals, plants, and microorganisms, including sulfide detoxification. the structures of two pdos from human and arabidopsis thaliana have been reported; however, little is known about the substrate binding and catalytic mechanism. the crystal structures of two bacterial pdos from pseudomo ...201526082492
new metabolic pathway for degradation of 2-nitrobenzoate by arthrobacter sp. spg.arthrobacter sp. spg utilized 2-nitrobenzoate as its sole source of carbon and energy and degraded it with accumulation of stoichiometric amounts of nitrite ions. salicylate and catechol were detected as metabolites of the 2-nitrobenzoate degradation using high performance liquid chromatography and gas chromatography-mass spectrometry. enzyme activities for 2-nitrobenzoate-2-monooxygenase, salicylate hydroxylase, and catechol-1,2-dioxygenase were detected in the crude extracts of the 2-nitrobenz ...201526082768
production of novel nan3-resistant creatine amidinohydrolase in recombinant escherichia coli.creatinase (creatine amidinohydrolase), an important medical enzyme, has been used for clinical diagnosis of renal function because of its high substrate specificity. recently, we successfully cloned a nan3-resistant creatinase encoding gene from arthrobacter nicotianae. by optimizing the cultivation process, we realized its high-level expression in escherichia coli. in this addendum, production of this nan3-resistant creatinase in e. coli and future research were further discussed.201526083084
impact of plant domestication on rhizosphere microbiome assembly and functions.the rhizosphere microbiome is pivotal for plant health and growth, providing defence against pests and diseases, facilitating nutrient acquisition and helping plants to withstand abiotic stresses. plants can actively recruit members of the soil microbial community for positive feedbacks, but the underlying mechanisms and plant traits that drive microbiome assembly and functions are largely unknown. domestication of plant species has substantially contributed to human civilization, but also cause ...201526085172
impact of plant domestication on rhizosphere microbiome assembly and functions.the rhizosphere microbiome is pivotal for plant health and growth, providing defence against pests and diseases, facilitating nutrient acquisition and helping plants to withstand abiotic stresses. plants can actively recruit members of the soil microbial community for positive feedbacks, but the underlying mechanisms and plant traits that drive microbiome assembly and functions are largely unknown. domestication of plant species has substantially contributed to human civilization, but also cause ...201526085172
rapidec carba np test for rapid detection of carbapenemase producers.performances of the rapidec carba np test (biomérieux) were evaluated for detection of all types of carbapenemases in enterobacteriaceae, acinetobacter baumannii, and pseudomonas aeruginosa. in less than 2 h after sample preparation, it showed a sensitivity and specificity of 96%. this ready-to-use test is well adapted to the daily need for detection of carbapenemase producers in any laboratory worldwide.201526085619
evaluation of an eventual ecotoxicity induced by textile effluents using a battery of biotests.textile industry is considered as one of the important factors of the economic growth in tunisia. however, this prominent role has certainly some drawbacks mainly represented by the huge amounts of textile wastewaters generated that become a real menace to nature. many previous studies showed the purifying potential of some activated sludge and bacteria (pseudomonas putida) to decolourize textile effluents. however, in many cases, decolourization of wastewaters is not necessary associated with d ...201526087930
pseudomonas putida-a versatile host for the production of natural products.the biosynthesis of natural products by heterologous expression of biosynthetic pathways in amenable production strains enables biotechnological access to a variety of valuable compounds by conversion of renewable resources. pseudomonas putida has emerged as a microbial laboratory work horse, with elaborated techniques for cultivation and genetic manipulation available. beyond that, this bacterium offers several particular advantages with regard to natural product biosynthesis, notably a versati ...201526099332
plasmid detection, characterization, and ecology.plasmids are important vehicles for rapid adaptation of bacterial populations to changing environmental conditions. it is thought that to reduce the cost of plasmid carriage, only a fraction of a local population carries plasmids or is permissive to plasmid uptake. plasmids provide various accessory traits which might be beneficial under particular conditions. the genetic variation generated by plasmid carriage within populations ensures the robustness toward environmental changes. plasmid-media ...201526104560
impact of biotic and a-biotic parameters on structure and function of microbial communities living on sclerotia of the soil-borne pathogenic fungus rhizoctonia solani.the plant pathogen rhizoctonia solani is very difficult to control due to its persistent, long-living sclerotial structures in soil. sclerotia are the main source of infection for rhizoctonia diseases, which cause high yield losses on a broad host range world-wide. little is known about micro-organisms associated with sclerotia in soil. therefore, microbial communities of greenhouse and field incubated rhizoctonia sclerotia were analysed by a multiphasic approach. using microbial fingerprints pe ...201126109749
genome, proteome and structure of a t7-like bacteriophage of the kiwifruit canker phytopathogen pseudomonas syringae pv. actinidiae.pseudomonas syringae pv. actinidiae is an economically significant pathogen responsible for severe bacterial canker of kiwifruit (actinidia sp.). bacteriophages infecting this phytopathogen have potential as biocontrol agents as part of an integrated approach to the management of bacterial canker, and for use as molecular tools to study this bacterium. a variety of bacteriophages were previously isolated that infect p. syringae pv. actinidiae, and their basic properties were characterized to pro ...201526114474
selection and evaluation of reference genes for reverse transcription-quantitative pcr expression studies in a thermophilic bacterium grown under different culture conditions.the phylum deinococcus-thermus is a deeply-branching lineage of bacteria widely recognized as one of the most extremophilic. members of the thermus genus are of major interest due to both their bioremediation and biotechnology potentials. however, the molecular mechanisms associated with these key metabolic pathways remain unknown. reverse-transcription quantitative pcr (rt-qpcr) is a high-throughput means of studying the expression of a large suite of genes over time and under different conditi ...201526115538
differential molecular response of monodehydroascorbate reductase and glutathione reductase by nitration and s-nitrosylation.the ascorbate-glutathione cycle is a metabolic pathway that detoxifies hydrogen peroxide and involves enzymatic and non-enzymatic antioxidants. proteomic studies have shown that some enzymes in this cycle such as ascorbate peroxidase (apx), monodehydroascorbate reductase (mdar), and glutathione reductase (gr) are potential targets for post-translational modifications (pmts) mediated by nitric oxide-derived molecules. using purified recombinant pea peroxisomal mdar and cytosolic and chloroplastic ...201526116026
development of spatial distribution patterns by biofilm cells.confined spatial patterns of microbial distribution are prevalent in nature, such as in microbial mats, soil communities, and water stream biofilms. the symbiotic two-species consortium of pseudomonas putida and acinetobacter sp. strain c6, originally isolated from a creosote-polluted aquifer, has evolved a distinct spatial organization in the laboratory that is characterized by an increased fitness and productivity. in this consortium, p. putida is reliant on microcolonies formed by acinetobact ...201526116674
phenotypic and phylogenetic identification of coliform bacteria obtained using 12 coliform methods approved by the u.s. environmental protection agency.the current definition of coliform bacteria is method dependent, and when different culture-based methods are used, discrepancies in results can occur and affect the accuracy of identification of true coliforms. this study used an alternative approach to the identification of true coliforms by combining the phenotypic traits of the coliform isolates and the phylogenetic affiliation of 16s rrna gene sequences with the use of lacz and uida genes. a collection of 1,404 isolates detected by 12 u.s. ...201526116679
structural and biochemical characterization of the francisella tularensis pathogenicity regulator, macrophage locus protein a (mgla).francisella tularensis is one of the most infectious bacteria known and is the etiologic agent of tularemia. francisella virulence arises from a 33 kilobase (kb) pathogenicity island (fpi) that is regulated by the macrophage locus protein a (mgla) and the stringent starvation protein a (sspa). these proteins interact with both rna polymerase (rnap) and the pathogenicity island gene regulator (pigr) to activate fpi transcription. however, the molecular mechanisms involved are not well understood. ...201526121147
label-free quantification reveals major proteomic changes in pseudomonas putida f1 during the exponential growth phase.the physiological adaptation to stationary growth by pseudomonas putida f1, a model organism for the degradation of aromatic compounds, was investigated by proteome-wide label-free quantification.the data unveiled that entrance to the stationary phase did not involve an abrupt switch within the p. putida f1 proteome, but rather an ongoing adaptation that started already during the mid-exponential growth phase. the proteomic adaptations involved a clear increase in amino acid degradation capabili ...201526122999
delicate conformational balance of the redox enzyme cytochrome p450cam.the energy landscapes of proteins are highly complex and can be influenced by changes in physical and chemical conditions under which the protein is studied. the redox enzyme cytochrome p450cam undergoes a multistep catalytic cycle wherein two electrons are transferred to the heme group and the enzyme visits several conformational states. using paramagnetic nmr spectroscopy with a lanthanoid tag, we show that the enzyme bound to its redox partner, putidaredoxin, is in a closed state at ambient t ...201526130807
unravelling the structural and molecular basis responsible for the anti-biofilm activity of zosteric acid.the natural compound zosteric acid, or p-(sulfoxy)cinnamic acid (za), is proposed as an alternative biocide-free agent suitable for preventive or integrative anti-biofilm approaches. despite its potential, the lack of information concerning the structural and molecular mechanism of action involved in its anti-biofilm activity has limited efforts to generate more potent anti-biofilm strategies. in this study a 43-member library of small molecules based on za scaffold diversity was designed and sc ...201526132116
tn7-based device for calibrated heterologous gene expression in pseudomonas putida.the soil bacterium pseudomonas putida is increasingly attracting considerable interest as a platform for advanced metabolic engineering through synthetic biology approaches. however, genomic context, gene copy number, and transcription/translation interplay often introduce considerable uncertainty to the design of reliable genetic constructs. in this work, we have established a standardized heterologous expression device in which the promoter strength is the only variable; the remaining paramete ...201526133359
solvent resistance pumps of pseudomonas putida s12: applications in 1-naphthol production and biocatalyst engineering.the solvent resistance capacity of pseudomonas putida s12 was applied by using the organism as a host for biocatalysis and through cloning and expressing solvent resistant pump genes into escherichia coli. p. putida s12 expressing toluene ortho mononooxygenase (tom-green) was used for 1-naphthol production in a water-organic solvent biphasic system. application of p. putida s12 improved 1-naphthol production per gram cell dry weight by approximately 42% compared to e. coli. moreover, p. putida s ...201526143210
heterofunctional magnetic metal-chelate-epoxy supports for the purification and covalent immobilization of benzoylformate decarboxylase from pseudomonas putida and its carboligation reactivity.in this study, the combined use of the selectivity of metal chelate affinity chromatography with the capacity of epoxy supports to immobilize poly-his-tagged recombinant benzoylformate decarboxylase from pseudomonas putida (bfd, e.c. 4.1.1.7) via covalent attachment is shown. this was achieved by designing tailor-made magnetic chelate-epoxy supports. in order to selectively adsorb and then covalently immobilize the poly-his-tagged bfd, the epoxy groups (300 µmol epoxy groups/g support) and a ver ...201526147067
crystal structure of a cog4313 outer membrane channel.cog4313 proteins form a large and widespread family of outer membrane channels and have been implicated in the uptake of a variety of hydrophobic molecules. structure-function studies of this protein family have so far been hampered by a lack of structural information. here we present the x-ray crystal structure of pput2725 from the biodegrader pseudomonas putida f1, a cog4313 channel of unknown function, using data to 2.3 å resolution. the structure shows a 12-stranded barrel with an n-terminal ...201526149193
microbial toluene removal in hypoxic model constructed wetlands occurs predominantly via the ring monooxygenation pathway.in the present study, microbial toluene degradation in controlled constructed wetland model systems, planted fixed-bed reactors (pfrs), was queried with dna-based methods in combination with stable isotope fractionation analysis and characterization of toluene-degrading microbial isolates. two pfr replicates were operated with toluene as the sole external carbon and electron source for 2 years. the bulk redox conditions in these systems were hypoxic to anoxic. the autochthonous bacterial communi ...201526150458
the regulatory function of lexa is temperature-dependent in the deep-sea bacterium shewanella piezotolerans wp3.the sos response addresses dna lesions and is conserved in the bacterial domain. the response is governed by the dna binding protein lexa, which has been characterized in model microorganisms such as escherichia coli. however, our understanding of its roles in deep-sea bacteria is limited. here, the influence of lexa on the phenotype and gene transcription of shewanella piezotolerans wp3 (wp3) was investigated by constructing a lexa deletion strain (wp3δlexa), which was compared with the wild-ty ...201526150814
synthetic biosensors for precise gene control and real-time monitoring of metabolites.characterization and standardization of inducible transcriptional regulators has transformed how scientists approach biology by allowing precise and tunable control of gene expression. despite their utility, only a handful of well-characterized regulators exist, limiting the complexity of engineered biological systems. we apply a characterization pipeline to four genetically encoded sensors that respond to acrylate, glucarate, erythromycin and naringenin. we evaluate how the concentration of the ...201526152303
the substrate tolerance of alcohol oxidases.alcohols are a rich source of compounds from renewable sources, but they have to be activated in order to allow the modification of their carbon backbone. the latter can be achieved via oxidation to the corresponding aldehydes or ketones. as an alternative to (thermodynamically disfavoured) nicotinamide-dependent alcohol dehydrogenases, alcohol oxidases make use of molecular oxygen but their application is under-represented in synthetic biotransformations. in this review, the mechanism of copper ...201526153139
rate-determining attack on substrate precedes rieske cluster oxidation during cis-dihydroxylation by benzoate dioxygenase.rieske dearomatizing dioxygenases utilize a rieske iron-sulfur cluster and a mononuclear fe(ii) located 15 å across a subunit boundary to catalyze o2-dependent formation of cis-dihydrodiol products from aromatic substrates. during catalysis, o2 binds to the fe(ii) while the substrate binds nearby. single-turnover reactions have shown that one electron from each metal center is required for catalysis. this finding suggested that the reactive intermediate is fe(iii)-(h)peroxo or ho-fe(v)═o formed ...201526154836
cytochrome p450 3a enzymes catalyze the o6-demethylation of thebaine, a key step in endogenous mammalian morphine biosynthesis.morphine, first characterized in opium from the poppy papaver somniferum, is one of the strongest known analgesics. endogenous morphine has been identified in several mammalian cells and tissues. the synthetic pathway of morphine in the opium poppy has been elucidated. the presence of common intermediates in plants and mammals suggests that biosynthesis occurs through similar pathways (beginning with the amino acid l-tyrosine), and the pathway has been completely delineated in plants. some of th ...201526157146
epidemiology and characteristics of metallo-β-lactamase-producing pseudomonas aeruginosa.metallo-β-lactamase-producing pseudomonas aeruginosa (mppa) is an important nosocomial pathogen that shows resistance to all β-lactam antibiotics except monobactams. there are various types of metallo-β-lactamases (mbls) in carbapenem-resistant p. aeruginosa including imipenemase (imp), verona integron-encoded metallo-β-lactamase (vim), sao paulo metallo-β-lactamase (spm), germany imipenemase (gim), new delhi metallo-β-lactamase (ndm), florence imipenemase (fim). each mbl gene is located on spec ...201526157586
lansoprazole is an antituberculous prodrug targeting cytochrome bc1.better antibiotics capable of killing multi-drug-resistant mycobacterium tuberculosis are urgently needed. despite extensive drug discovery efforts, only a few promising candidates are on the horizon and alternative screening protocols are required. here, by testing a panel of fda-approved drugs in a host cell-based assay, we show that the blockbuster drug lansoprazole (prevacid), a gastric proton-pump inhibitor, has intracellular activity against m. tuberculosis. ex vivo pharmacokinetics and ta ...201526158909
the bacterial phosphotransferase system: new frontiers 50 years after its discovery.in 1964, kundig, ghosh and roseman reported the discovery of the phosphoenolpyruvate:sugar phosphotransferase system (pts), which they subsequently proposed might catalyze sugar transport as well as sugar phosphorylation. what we have learned in the 50 years since its discovery is that, in addition to these primary functions, the pts serves as a complex protein kinase system that regulates a wide variety of transport, metabolic and mutagenic processes as well as the expression of numerous genes. ...201526159069
modeling the interplay of pseudomonas putida eiia with the potassium transporter kdpfabc.the nitrogen phosphotransferase system (pts(ntr)) of pseudomonas putida is a key regulatory device that participates in controlling many physiological processes in a posttranscriptional fashion. one of the target functions of the pts(ntr) is the regulation of potassium transport. this is mediated by the direct interaction of one of its components with the sensor kinase kdpd of the two-component system controlling transcription of the kdpfabc genes. from a detailed experimental analysis of the ac ...201526159078
salix purpurea stimulates the expression of specific bacterial xenobiotic degradation genes in a soil contaminated with hydrocarbons.the objectives of this study were to uncover salix purpurea-microbe xenobiotic degradation systems that could be harnessed in rhizoremediation, and to identify microorganisms that are likely involved in these partnerships. to do so, we tested s. purpurea's ability to stimulate the expression of 10 marker microbial oxygenase genes in a soil contaminated with hydrocarbons. in what appeared to be a detoxification rhizosphere effect, transcripts encoding for alkane 1-monooxygenases, cytochrome p450 ...201526161539
the role of amino acid permeases and tryptophan biosynthesis in cryptococcus neoformans survival.metabolic diversity is an important factor during microbial adaptation to different environments. among metabolic processes, amino acid biosynthesis has been demonstrated to be relevant for survival for many microbial pathogens, whereas the association between pathogenesis and amino acid uptake and recycling are less well-established. cryptococcus neoformans is an opportunistic fungal pathogen with many habitats. as a result, it faces frequent metabolic shifts and challenges during its life cycl ...201526162077
quantitative polymerase chain reaction for microbial growth kinetics of mixed culture system.microbial growth kinetics is often used to optimize environmental processes owing to its relation to the breakdown of substrate (contaminants). however, the quantification of bacterial populations in the environment is difficult owing to the challenges of monitoring a specific bacterial population within a diverse microbial community. conventional methods are unable to detect and quantify the growth of individual strains separately in the mixed culture reactor. this work describes a novel quanti ...201526165316
identification of differentially abundant proteins of edwardsiella ictaluri during iron restriction.edwardsiella ictaluri is a gram-negative facultative anaerobe intracellular bacterium that causes enteric septicemia in channel catfish. iron is an essential inorganic nutrient of bacteria and is crucial for bacterial invasion. reduced availability of iron by the host may cause significant stress for bacterial pathogens and is considered a signal that leads to significant alteration in virulence gene expression. however, the precise effect of iron-restriction on e. ictaluri protein abundance is ...201526168192
functional expression, purification, and biochemical properties of subtilase sprp from pseudomonas aeruginosa.the pseudomonas aeruginosa genome encodes a variety of different proteolytic enzymes several of which play an important role as virulence factors. interestingly, only two of these proteases are predicted to belong to the subtilase family and we have recently studied the physiological role of the subtilase sprp. here, we describe the functional overexpression of sprp in escherichia coli using a novel expression and secretion system. we show that sprp is autocatalytically activated by proteolysis ...201526175208
biotechnological applications of functional metagenomics in the food and pharmaceutical industries.microorganisms are found throughout nature, thriving in a vast range of environmental conditions. the majority of them are unculturable or difficult to culture by traditional methods. metagenomics enables the study of all microorganisms, regardless of whether they can be cultured or not, through the analysis of genomic data obtained directly from an environmental sample, providing knowledge of the species present, and allowing the extraction of information regarding the functionality of microbia ...201526175729
biodegradation of polychlorinated biphenyls (pcbs) by the novel identified cyanobacterium anabaena pd-1.polychlorinated biphenyls (pcbs), a class of hazardous pollutants, are difficult to dissipate in the natural environment. in this study, a cyanobacterial strain anabaena pd-1 showed good resistance against pcb congeners. compared to a control group, chlorophyll a content decreased 3.7% and 11.7% when anabaena pd-1 was exposed to 2 and 5 mg/l pcbs for 7 d. this cyanobacterial strain was capable of decomposing pcb congeners which was conclusively proved by determination of chloride ion concentrati ...201526177203
dynamic response of pseudomonas putida s12 to sudden addition of toluene and the potential role of the solvent tolerance gene trgi.pseudomonas putida s12 is exceptionally tolerant to various organic solvents. to obtain further insight into this bacterium's primary defence mechanisms towards these potentially harmful substances, we studied its genome wide transcriptional response to sudden addition of toluene. global gene expression profiles were monitored for 30 minutes after toluene addition. during toluene exposure, high oxygen-affinity cytochrome c oxidase is specifically expressed to provide for an adequate proton gradi ...201526181384
a portable expression resource for engineering cross-species genetic circuits and pathways.genetic circuits and metabolic pathways can be reengineered to allow organisms to process signals and manufacture useful chemicals. however, their functions currently rely on organism-specific regulatory parts, fragmenting synthetic biology and metabolic engineering into host-specific domains. to unify efforts, here we have engineered a cross-species expression resource that enables circuits and pathways to reuse the same genetic parts, while functioning similarly across diverse organisms. our e ...201526184393
genetically engineering bacillus subtilis with a heat-resistant arsenite methyltransferase for bioremediation of arsenic-contaminated organic waste.organic manures may contain high levels of arsenic (as) due to the use of as-containing growth-promoting substances in animal feed. to develop a bioremediation strategy to remove as from organic waste, bacillus subtilis 168, a bacterial strain which can grow at high temperature but is unable to methylate and volatilize as, was genetically engineered to express the arsenite s-adenosylmethionine methyltransferase gene (cmarsm) from the thermophilic alga cyanidioschyzon merolae. the genetically eng ...201526187966
nitrile as activating group in the asymmetric bioreduction of β-cyanoacrylic acids catalyzed by ene-reductases.asymmetric bioreduction of an (e)-β-cyano-2,4-dienoic acid derivative by ene-reductases allowed a shortened access to a precursor of pregabalin [(s)-3-(aminomethyl)-5-methylhexanoic acid] possessing the desired configuration in up to 94% conversion and >99% ee. deuterium labelling studies showed that the nitrile moiety was the preferred activating/anchor group in the active site of the enzyme over the carboxylic acid or the corresponding methyl ester.201426190962
transcription factor-based biosensors enlightened by the analyte.whole cell biosensors (wcbs) have multiple applications for environmental monitoring, detecting a wide range of pollutants. wcbs depend critically on the sensitivity and specificity of the transcription factor (tf) used to detect the analyte. we describe the mechanism of regulation and the structural and biochemical properties of tf families that are used, or could be used, for the development of environmental wcbs. focusing on the chemical nature of the analyte, we review tfs that respond to ar ...201526191047
allopatric integrations selectively change host transcriptomes, leading to varied expression efficiencies of exotic genes in myxococcus xanthus.exotic genes, especially clustered multiple-genes for a complex pathway, are normally integrated into chromosome for heterologous expression. the influences of insertion sites on heterologous expression and allotropic expressions of exotic genes on host remain mostly unclear.201526194479
regulation mechanism of the ald gene encoding alanine dehydrogenase in mycobacterium smegmatis and mycobacterium tuberculosis by the lrp/asnc family regulator aldr.in the presence of alanine, aldr, which belongs to the lrp/asnc family of transcriptional regulators and regulates ald encoding alanine dehydrogenase in mycobacterium smegmatis, changes its quaternary structure from a homodimer to an octamer with an open-ring conformation. four aldr-binding sites (o2, o1, o4, and o3) with a consensus sequence of ga/t-n2-nww/wwn-n2-a/tc were identified upstream of the m. smegmatis ald gene by means of dnase i footprinting analysis. o2, o1, and o4 are required for ...201526195594
entner-doudoroff pathway for sulfoquinovose degradation in pseudomonas putida sq1.sulfoquinovose (sq; 6-deoxy-6-sulfoglucose) is the polar head group of the plant sulfolipid sq-diacylglycerol, and sq comprises a major proportion of the organosulfur in nature, where it is degraded by bacteria. a first degradation pathway for sq has been demonstrated recently, a "sulfoglycolytic" pathway, in addition to the classical glycolytic (embden-meyerhof) pathway in escherichia coli k-12; half of the carbon of sq is abstracted as dihydroxyacetonephosphate (dhap) and used for growth, wher ...201526195800
bioactive 7-oxabicyclic[6.3.0]lactam and 12-membered macrolides from a gorgonian-derived cladosporium sp. fungus.one new bicyclic lactam, cladosporilactam a (1), and six known 12-membered macrolides (2-7) were isolated from a gorgonian-derived cladosporium sp. fungus collected from the south china sea. their complete structural assignments were elucidated by comprehensive spectroscopic investigation. quantum chemistry calculations were used in support of the structural determination of 1. the absolute configuration of 1 was determined by calculation of its optical rotation. cladosporilactam a (1) was the f ...201526198234
unearthing the genomes of plant-beneficial pseudomonas model strains wcs358, wcs374 and wcs417.plant growth-promoting rhizobacteria (pgpr) can protect plants against pathogenic microbes through a diversity of mechanisms including competition for nutrients, production of antibiotics, and stimulation of the host immune system, a phenomenon called induced systemic resistance (isr). in the past 30 years, the pseudomonas spp. pgpr strains wcs358, wcs374 and wcs417 of the willie commelin scholten (wcs) collection have been studied in detail in pioneering papers on the molecular basis of pgpr-me ...201526198432
cyanobacteria: photoautotrophic microbial factories for the sustainable synthesis of industrial products.cyanobacteria are widely distributed gram-negative bacteria with a long evolutionary history and the only prokaryotes that perform plant-like oxygenic photosynthesis. cyanobacteria possess several advantages as hosts for biotechnological applications, including simple growth requirements, ease of genetic manipulation, and attractive platforms for carbon neutral production process. the use of photosynthetic cyanobacteria to directly convert carbon dioxide to biofuels is an emerging area of intere ...201526199945
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