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intracellularly induced cyclophilins play an important role in stress adaptation and virulence of brucella abortus.brucella is an intracellular bacterial pathogen that causes the worldwide zoonotic disease brucellosis. brucella virulence relies on its ability to transition to an intracellular lifestyle within host cells. thus, this pathogen must sense its intracellular localization and then reprogram gene expression for survival within the host cell. a comparative proteomic investigation was performed to identify differentially expressed proteins potentially relevant for brucella intracellular adaptation. tw ...201323230297
genomic analysis of melioribacter roseus, facultatively anaerobic organotrophic bacterium representing a novel deep lineage within bacteriodetes/chlorobi group.melioribacter roseus is a moderately thermophilic facultatively anaerobic organotrophic bacterium representing a novel deep branch within bacteriodetes/chlorobi group. to better understand the metabolic capabilities and possible ecological functions of m. roseus and get insights into the evolutionary history of this bacterial lineage, we sequenced the genome of the type strain p3m-2(t). a total of 2838 open reading frames was predicted from its 3.30 mb genome. the whole proteome analysis support ...201323301019
champacyclin, a new cyclic octapeptide from streptomyces strain c42 isolated from the baltic sea.new isolates of streptomyces champavatii were isolated from marine sediments of the gotland deep (baltic sea), from the urania basin (eastern mediterranean), and from the kiel bight (baltic sea). the isolates produced several oligopeptidic secondary metabolites, including the new octapeptide champacyclin (1a) present in all three strains. herein, we report on the isolation, structure elucidation and determination of the absolute stereochemistry of this isoleucine/leucine (ile/leu = xle) rich cyc ...201324317473
hydrogen peroxide- and nitric oxide-mediated disease control of bacterial wilt in tomato plants.reactive oxygen species (ros) generation in tomato plants by ralstonia solanacearum infection and the role of hydrogen peroxide (h2o2) and nitric oxide in tomato bacterial wilt control were demonstrated. during disease development of tomato bacterial wilt, accumulation of superoxide anion (o2 (-)) and h2o2 was observed and lipid peroxidation also occurred in the tomato leaf tissues. high doses of h2o2and sodium nitroprusside (snp) nitric oxide donor showed phytotoxicity to detached tomato leaves ...201325288967
structural insights into a novel interkingdom signaling circuit by cartography of the ligand-binding sites of the homologous quorum sensing luxr-family.recent studies have identified a novel interkingdom signaling circuit, via plant signaling molecules, and a bacterial sub-family of luxr proteins, bridging eukaryotes and prokaryotes. indeed pivotal plant-bacteria interactions are regulated by the so called plant associated bacteria (pab) luxr solo regulators that, although closely related to the quorum sensing (qs) luxr family, do not bind or respond to canonical quorum sensing n-acyl homoserine lactones (ahls), but only to specific host plant ...201324132148
identification and molecular characterization of ysal (ye3555): a novel negative regulator of ysan atpase in type three secretion system of enteropathogenic bacteria yersinia enterocolitica.type three secretion (t3s) atpases are involved in delivery of virulent factors from bacteria to their hosts (through injectisome) in an energy (atp) dependent manner during pathogenesis. the activities of these atpases are tightly controlled by their specific regulators. in yersinia enterocolitica, ysan was predicted as a putative atpase of the ysa-ysp type three secretion system (t3ss) based on sequence similarity with other t3s atpases. however detailed study and characterization of ysan and ...201324124464
characterization of maltocin p28, a novel phage tail-like bacteriocin from stenotrophomonas maltophilia.stenotrophomonas maltophilia is an important global opportunistic pathogen for which limited therapeutics are available because of the emergence of multidrug-resistant strains. a novel bacteriocin, maltocin p28, which is produced by s. maltophilia strain p28, may be the first identified phage tail-like bacteriocin from s. maltophilia. maltocin p28 resembles a contractile but nonflexible phage tail structure based on electron microscopy, and it is sensitive to trypsin, proteinase k, and heat. sds ...201323835182
sequence-based discovery of bradyrhizobium enterica in cord colitis syndrome.immunosuppression is associated with a variety of idiopathic clinical syndromes that may have infectious causes. it has been hypothesized that the cord colitis syndrome, a complication of umbilical-cord hematopoietic stem-cell transplantation, is infectious in origin.201323924002
insights into xanthomonas axonopodis pv. citri biofilm through proteomics.xanthomonas axonopodis pv. citri (x. a. pv. citri) causes citrus canker that can result in defoliation and premature fruit drop with significant production losses worldwide. biofilm formation is an important process in bacterial pathogens and several lines of evidence suggest that in x. a. pv. citri this process is a requirement to achieve maximal virulence since it has a major role in host interactions. in this study, proteomics was used to gain further insights into the functions of biofilms.201323924281
complete sequence of poz176, a 500-kilobase incp-2 plasmid encoding imp-9-mediated carbapenem resistance, from outbreak isolate pseudomonas aeruginosa 96.pseudomonas aeruginosa 96 (pa96) was isolated during a multicenter surveillance study in guangzhou, china, in 2000. whole-genome sequencing of this outbreak strain facilitated analysis of its incp-2 carbapenem-resistant plasmid, poz176. the plasmid had a length of 500,839 bp and an average percent g+c content of 57%. of the 618 predicted open reading frames, 65% encode hypothetical proteins. the poz176 backbone is not closely related to any plasmids thus far sequenced, but some similarity to pqb ...201323716048
mycorrhiza-induced resistance: more than the sum of its parts?plants can develop an enhanced defensive capacity in response to infection by arbuscular mycorrhizal fungi (amf). this 'mycorrhiza-induced resistance' (mir) provides systemic protection against a wide range of attackers and shares characteristics with systemic acquired resistance (sar) after pathogen infection and induced systemic resistance (isr) following root colonisation by non-pathogenic rhizobacteria. it is commonly assumed that fungal stimulation of the plant immune system is solely respo ...201323871659
a review on phytochemistry and ethnopharmacological aspects of genus calendula.this review includes 84 references on the genus calendula (asteraceae) and comprises ethnopharmacology, morphology and microscopy, phytoconstituents, pharmacological reports, clinical studies and toxicology of the prominent species of calendula. triterpene alcohols, triterpene saponins, flavonoids, carotenoids and polysaccharides constitute major classes of phytoconstituents of the genus. a few species of this genus have medicinal value, among these calendula officinalis linn., has been traditio ...201324347926
evolution of rep diversity: a comparative study.repetitive extragenic palindromic elements (reps) constitute a group of bacterial genomic repeats known for their high abundance and several roles in host cells´ physiology. we analyzed the phylogenetic distribution of particular rep classes in genomic sequences of sixty-three bacterial strains belonging to the pseudomonas fluorescens species complex and ten strains of stenotrophomonas sp., in order to assess intraspecific rep diversity and to gain insight into long-term rep evolution.201323758774
a novel two-component response regulator links rpf with biofilm formation and virulence of xanthomonas axonopodis pv. citri.citrus bacterial canker caused by xanthomonas axonopodis pv. citri is a serious disease that impacts citrus production worldwide, and x. axonopodis pv. citri is listed as a quarantine pest in certain countries. biofilm formation is important for the successful development of a pathogenic relationship between various bacteria and their host(s). to understand the mechanisms of biofilm formation by x. axonopodis pv. citri strain xw19, the strain was subjected to transposon mutagenesis. one mutant w ...201323626857
bean common bacterial blight: pathogen epiphytic life and effect of irrigation practices.in recent years, bean common bacterial blight (cbb) caused by xanthomonas axonopodis pv. phaseoli (xap) has caused serious yield losses in several countries. cbb is considered mainly a foliar disease in which symptoms initially appear as small water-soaked spots that then enlarge and become necrotic and usually bordered by a chlorotic zone. xap epiphytic population community has a critical role in the development of the disease and subsequent epidemics. the epiphytic population of xap in the fie ...201323539532
recruitment and rearrangement of three different genetic determinants into a conjugative plasmid increase copper resistance in pseudomonas syringae.we describe the genetic organization of a copper-resistant plasmid containing copg and cuscba genes in the plant pathogen pseudomonas syringae. chromosomal variants of czccba and a plasmid variant of cuscba were present in different p. syringae pathovar strains. transformation of the copper-sensitive pseudomonas syringae pv. syringae ff5 strain with copg or cuscba conferred copper resistance, and quantitative real-time pcr (qrt-pcr) experiments confirmed their induction by copper.201323183969
the antagonistic strain bacillus subtilis umaf6639 also confers protection to melon plants against cucurbit powdery mildew by activation of jasmonate- and salicylic acid-dependent defence responses.biological control of plant diseases has gained acceptance in recent years. bacillus subtilis umaf6639 is an antagonistic strain specifically selected for the efficient control of the cucurbit powdery mildew fungus podosphaera fusca, which is a major threat to cucurbits worldwide. the antagonistic activity relies on the production of the antifungal compounds iturin and fengycin. in a previous study, we found that umaf6639 was able to induce systemic resistance (isr) in melon and provide addition ...201323302493
proteinaceous determinants of surface colonization in bacteria: bacterial adhesion and biofilm formation from a protein secretion perspective.bacterial colonization of biotic or abiotic surfaces results from two quite distinct physiological processes, namely bacterial adhesion and biofilm formation. broadly speaking, a biofilm is defined as the sessile development of microbial cells. biofilm formation arises following bacterial adhesion but not all single bacterial cells adhering reversibly or irreversibly engage inexorably into a sessile mode of growth. among molecular determinants promoting bacterial colonization, surface proteins a ...201324133488
cis-2-dodecenoic acid quorum sensing system modulates n-acyl homoserine lactone production through rpfr and cyclic di-gmp turnover in burkholderia cenocepacia.burkholderia cenocepacia employs both n-acyl homoserine lactone (ahl) and cis-2-dodecenoic acid (bdsf) quorum sensing (qs) systems in regulation of bacterial virulence. it was shown recently that disruption of bdsf synthase rpffbc caused a reduction of ahl signal production in b. cenocepacia. however, how bdsf system influences ahl system is still not clear.201323815566
two quorum sensing systems control biofilm formation and virulence in members of the burkholderia cepacia complex.the burkholderia cepacia complex (bcc) consists of 17 closely related species that are problematic opportunistic bacterial pathogens for cystic fibrosis patients and immunocompromised individuals. these bacteria are capable of utilizing two different chemical languages: n-acyl homoserine lactones (ahls) and cis-2-unsaturated fatty acids. here we summarize the current knowledge of the underlying molecular architectures of these communication systems, showing how they are interlinked and discussin ...201323799665
mamp (microbe-associated molecular pattern) triggered immunity in plants.plants are sessile organisms that are under constant attack from microbes. they rely on both preformed defenses, and their innate immune system to ward of the microbial pathogens. preformed defences include for example the cell wall and cuticle, which act as physical barriers to microbial colonization. the plant immune system is composed of surveillance systems that perceive several general microbe elicitors, which allow plants to switch from growth and development into a defense mode, rejecting ...201323720666
interspecies interaction between pseudomonas aeruginosa and other microorganisms.microbes interact with each other in multicellular communities and this interaction enables certain microorganisms to survive in various environments. pseudomonas aeruginosa is a highly adaptable bacterium that ubiquitously inhabits diverse environments including soil, marine habitats, plants and animals. behind this adaptivity, p. aeruginosa has abilities not only to outcompete others but also to communicate with each other to develop a multispecies community. in this review, we focus on how p. ...201323363620
phenotypic and genotypic characterisation of burkholderia cenocepacia j2315 mutants affected in homoserine lactone and diffusible signal factor-based quorum sensing systems suggests interplay between both types of systems.many putative virulence factors of burkholderia cenocepacia are controlled by various quorum sensing (qs) circuits. these qs systems either use n-acyl homoserine lactones (ahl) or cis-2-dodecenoic acid ("burkholderia diffusible signal factor", bdsf) as signalling molecules. previous work suggested that there is little cross-talk between both types of systems. we constructed mutants in b. cenocepacia strain j2315, in which genes encoding cepi (bcam1870), ccii (bcam0239a) and the bdsf synthase (bc ...201323383071
the lov protein of xanthomonas citri subsp. citri plays a significant role in the counteraction of plant immune responses during citrus canker.pathogens interaction with a host plant starts a set of immune responses that result in complex changes in gene expression and plant physiology. light is an important modulator of plant defense response and recent studies have evidenced the novel influence of this environmental stimulus in the virulence of several bacterial pathogens. xanthomonas citri subsp. citri is the bacterium responsible for citrus canker disease, which affects most citrus cultivars. the ability of this bacterium to coloni ...201324260514
identification and characterization of ribn, a novel family of riboflavin transporters from rhizobium leguminosarum and other proteobacteria.rhizobia are symbiotic bacteria able to invade and colonize the roots of legume plants, inducing the formation of nodules, where bacteria reduce atmospheric nitrogen (n2) to ammonia (nh3). riboflavin availability influences the capacity of rhizobia to survive in the rhizosphere and to colonize roots. in this study, we identified the rl1692 gene of rhizobium leguminosarum downstream of a flavin mononucleotide (fmn) riboswitch. rl1692 encodes a putative transmembrane permease with two eama domains ...201323935051
small rna-mediated regulation of host-pathogen interactions.the rise in antimicrobial drug resistance, alongside the failure of conventional research to discover new antibiotics, will inevitably lead to a public health crisis that can drastically curtail our ability to combat infectious disease. thus, there is a great global health need for development of antimicrobial countermeasures that target novel cell molecules or processes. rna represents a largely unexploited category of potential targets for antimicrobial design. for decades, control of cellular ...201323958954
global small rna chaperone hfq and regulatory small rnas are important virulence regulators in erwinia amylovora.hfq is a global small rna (srna) chaperone that interacts with hfq-regulated srnas and functions in the posttranscriptional regulation of gene expression. in this work, we identified hfq to be a virulence regulator in the gram-negative fire blight pathogen erwinia amylovora. deletion of hfq in e. amylovora ea1189 significantly reduced bacterial virulence in both immature pear fruits and apple shoots. analysis of virulence determinants in strain ea1189δhfq showed that hfq exerts pleiotropic regul ...201323378513
intrigues and intricacies of the biosynthetic pathways for the enzymatic quinocofactors: pqq, ttq, ctq, tpq, and ltq. 201324350630
intrigues and intricacies of the biosynthetic pathways for the enzymatic quinocofactors: pqq, ttq, ctq, tpq, and ltq. 201324350630
isolation of rhizospheric and roots endophytic actinomycetes from leguminosae plant and their activities to inhibit soybean pathogen, xanthomonas campestris pv. glycine.in this study, actinomycetes from roots and rhizospheric soils of leguminous plants were isolated using starch casein agar supplemented with antifungal and antibacterial antibiotics. three hundred and seventeen actinomycetes were isolated with 77 isolates obtained from plant roots and 240 isolates from rhizospheric soils. analysis of whole-organism hydrolysates showed that 289 strains were rich in the ll-isomer of diaminopimelic acid, a result consistent with their assignment to the streptomycet ...201323913026
functional screening of metagenome and genome libraries for detection of novel flavonoid-modifying enzymes.the functional detection of novel enzymes other than hydrolases from metagenomes is limited since only a very few reliable screening procedures are available that allow the rapid screening of large clone libraries. for the discovery of flavonoid-modifying enzymes in genome and metagenome clone libraries, we have developed a new screening system based on high-performance thin-layer chromatography (hptlc). this metagenome extract thin-layer chromatography analysis (meta) allows the rapid detection ...201323686272
exploiting quorum sensing to confuse bacterial pathogens.cell-cell communication, or quorum sensing, is a widespread phenomenon in bacteria that is used to coordinate gene expression among local populations. its use by bacterial pathogens to regulate genes that promote invasion, defense, and spread has been particularly well documented. with the ongoing emergence of antibiotic-resistant pathogens, there is a current need for development of alternative therapeutic strategies. an antivirulence approach by which quorum sensing is impeded has caught on as ...201323471618
heterologous expression of mycobacterial esx complexes in escherichia coli for structural studies is facilitated by the use of maltose binding protein fusions.the expression of heteroligomeric protein complexes for structural studies often requires a special coexpression strategy. the reason is that the solubility and proper folding of each subunit of the complex requires physical association with other subunits of the complex. the genomes of pathogenic mycobacteria encode many small protein complexes, implicated in bacterial fitness and pathogenicity, whose characterization may be further complicated by insolubility upon expression in escherichia col ...201324312350
crystal structure of an hd-gyp domain cyclic-di-gmp phosphodiesterase reveals an enzyme with a novel trinuclear catalytic iron centre.bis-(3',5') cyclic di-guanylate (c-di-gmp) is a key bacterial second messenger that is implicated in the regulation of many crucial processes that include biofilm formation, motility and virulence. cellular levels of c-di-gmp are controlled through synthesis by ggdef domain diguanylate cyclases and degradation by two classes of phosphodiesterase with eal or hd-gyp domains. here, we have determined the structure of an enzymatically active hd-gyp domain protein from persephonella marina (pmgh) alo ...201324176013
crystal structure of an hd-gyp domain cyclic-di-gmp phosphodiesterase reveals an enzyme with a novel trinuclear catalytic iron centre.bis-(3',5') cyclic di-guanylate (c-di-gmp) is a key bacterial second messenger that is implicated in the regulation of many crucial processes that include biofilm formation, motility and virulence. cellular levels of c-di-gmp are controlled through synthesis by ggdef domain diguanylate cyclases and degradation by two classes of phosphodiesterase with eal or hd-gyp domains. here, we have determined the structure of an enzymatically active hd-gyp domain protein from persephonella marina (pmgh) alo ...201324176013
c-di-gmp hydrolysis by pseudomonas aeruginosa hd-gyp phosphodiesterases: analysis of the reaction mechanism and novel roles for pgpg.in biofilms, the bacterial community optimizes the strategies to sense the environment and to communicate from cell to cell. a key player in the development of a bacterial biofilm is the second messenger c-di-gmp, whose intracellular levels are modulated by the opposite activity of diguanylate cyclases and phosphodiesterases. given the huge impact of bacterial biofilms on human health, understanding the molecular details of c-di-gmp metabolism represents a critical step in the development of nov ...201324066157
cyclic di-gmp signalling and the regulation of bacterial virulence.signal transduction pathways involving the second messenger cyclic di-gmp [bis-(3'-5')-cyclic di-guanosine monophosphate] occur widely in bacteria where they act to link perception of environmental or intracellular cues and signals to specific alterations in cellular function. such alterations can contribute to bacterial lifestyle transitions including biofilm formation and virulence. the cellular levels of the nucleotide are controlled through the opposing activities of diguanylate cyclases (dg ...201323704785
cyclic di-gmp: the first 25 years of a universal bacterial second messenger.twenty-five years have passed since the discovery of cyclic dimeric (3'→5') gmp (cyclic di-gmp or c-di-gmp). from the relative obscurity of an allosteric activator of a bacterial cellulose synthase, c-di-gmp has emerged as one of the most common and important bacterial second messengers. cyclic di-gmp has been shown to regulate biofilm formation, motility, virulence, the cell cycle, differentiation, and other processes. most c-di-gmp-dependent signaling pathways control the ability of bacteria t ...201323471616
establishment of an inducing medium for type iii effector secretion in xanthomonas campestris pv. campestris.it is well known that the type iii secretion system (t3ss) and type iii (t3) effectors are essential for the pathogenicity of most bacterial phytopathogens and that the expression of t3ss and t3 effectors is suppressed in rich media but induced in minimal media and plants. to facilitate in-depth studies on t3ss and t3 effectors, it is crucial to establish a medium for t3 effector expression and secretion. xanthomonas campestris pv. campestris (xcc) is a model bacterium for studying plant-pathoge ...201324516463
establishment of an inducing medium for type iii effector secretion in xanthomonas campestris pv. campestris.it is well known that the type iii secretion system (t3ss) and type iii (t3) effectors are essential for the pathogenicity of most bacterial phytopathogens and that the expression of t3ss and t3 effectors is suppressed in rich media but induced in minimal media and plants. to facilitate in-depth studies on t3ss and t3 effectors, it is crucial to establish a medium for t3 effector expression and secretion. xanthomonas campestris pv. campestris (xcc) is a model bacterium for studying plant-pathoge ...201324516463
perception of the novel mamp emax from different xanthomonas species requires the arabidopsis receptor-like protein remax and the receptor kinase sobir.as part of their innate immune system plants carry a number of pattern recognition receptors (prrs) that can detect a broad range of microbe-associated molecular patterns (mamps). in a recently published article (1) we described a novel, proteinaceous mamp termed emax (enigmatic mamp of xanthomonas) that derives from xanthomonas and gets recognized by the receptor-like protein remax (receptor of emax) of arabidopsis thaliana. remax has no ortholog in nicotiana benthamiana and this species does n ...201324384530
secretory pathway of cellulase: a mini-review.cellulase plays an important role in modern industry and holds great potential in biofuel production. many different types of organisms produce cellulase, which go through secretory pathways to reach the extracellular space, where enzymatic reactions take place. secretory pathways in various cells have been the focus of many research fields; however, there are few studies on secretory pathways of cellulases in the literature. it is therefore necessary and important to review the current knowledg ...201324295495
xanthomonas oryzae pv. oryzae rpfe regulates virulence and carbon source utilization without change of the dsf production.it has been known that most regulation of pathogenicity factor (rpf) genes in xanthomonads regulates virulence in response to the diffusible signal factor, dsf. although many rpf genes have been functionally characterized, the function of rpfe is still unknown. we cloned the rpfe gene from a xanthomonas oryzae pv. oryzae (xoo) korean race kacc10859 and generated mutant strains to elucidate the role of rpfe with respect to the rpf system. through experiments using the rpfe-deficient mutant strain ...201325288965
diffusible signal factor (dsf) synthase rpff of xylella fastidiosa is a multifunction protein also required for response to dsf.xylella fastidiosa, like related xanthomonas species, employs an rpf cell-cell communication system consisting of a diffusible signal factor (dsf) synthase, rpff, and a dsf sensor, rpfc, to coordinate expression of virulence genes. while phenotypes of a δrpff strain in xanthomonas campestris could be complemented by its own dsf, the dsf produced by x. fastidiosa (xfdsf) did not restore expression of the xfdsf-dependent genes hxfa and hxfb to a δrpff strain of x. fastidiosa, suggesting that rpff ...201324056101
investigating the allosteric regulation of yfin from pseudomonas aeruginosa: clues from the structure of the catalytic domain.pseudomonas aeruginosa is responsible for a plethora of biofilm mediated chronic infections among which cystic fibrosis pneumonia is the most frightening. the long-term survival strategy of p. aeruginosa in the patients lungs is based on a fine balance of virulence vs dormant states and on genetic adaptation, in order to select persistent phenotypes as the small colony variants (scvs), which strongly correlate with antibiotic resistance and poor lung function. recent studies have coupled scv wit ...201324278422
an r package for snp marker-based parent-offspring tests.with the advancement of genotyping technologies, whole genome and high-density snp markers have been widely used for genotyping of mapping populations and for characterization of germplasm lines in many crops. before conducting snp data analysis, it is necessary to check the individuals to ensure the integrity of lines for further data analysis.201324245988
enhancement of oxygen mass transfer and gas holdup using palm oil in stirred tank bioreactors with xanthan solutions as simulated viscous fermentation broths.volumetric mass transfer coefficient (kla) is an important parameter in bioreactors handling viscous fermentations such as xanthan gum production, as it affects the reactor performance and productivity. published literatures showed that adding an organic phase such as hydrocarbons or vegetable oil could increase the kla. the present study opted for palm oil as the organic phase as it is plentiful in malaysia. experiments were carried out to study the effect of viscosity, gas holdup, and kla on t ...201324350269
bacterial luxr solos have evolved to respond to different molecules including signals from plants.a future challenge will be understanding the extensive communication that most likely takes place in bacterial interspecies and interkingdom signaling between plants and bacteria. a major bacterial inter-cellular signaling system in gram-negative bacteria is luxi/r quorum sensing (qs) based on the production (via the luxi-family proteins) and detection (via the luxr-family proteins) of n-acyl homoserine lactones (ahls) signaling molecules. luxr proteins which have the same modular structure of q ...201324273546
a comprehensive meta qtl analysis for fiber quality, yield, yield related and morphological traits, drought tolerance, and disease resistance in tetraploid cotton.the study of quantitative trait loci (qtl) in cotton (gossypium spp.) is focused on traits of agricultural significance. previous studies have identified a plethora of qtl attributed to fiber quality, disease and pest resistance, branch number, seed quality and yield and yield related traits, drought tolerance, and morphological traits. however, results among these studies differed due to the use of different genetic populations, markers and marker densities, and testing environments. since two ...201324215677
sustained release of diltiazem hydrochloride from cross-linked biodegradable ipn hydrogel beads of pectin and modified xanthan gum.interpenetrating polymer network hydrogel beads of pectin and sodium carboxymethyl xanthan were prepared by ionotropic gelation with al(+3) ions and covalent cross-linking with glutaraldehyde for sustained delivery of diltiazem hydrochloride. fourier transform infrared spectroscopy, x-ray diffraction, differential scanning colorimetry and scanning electron microscopy were used to characterise the hydrogel beads. the swelling of the hydrogel and the release of drug were relatively low in ph 1.2 b ...201324591735
sensing of the microbial neighborhood by candida albicans. 201324204254
cyclic diguanosine monophosphate represses bacterial flagella synthesis by interacting with the walker a motif of the enhancer-binding protein fleq.the transcription factor fleq is a bacterial aaa+ atpase enhancer-binding protein that is the master activator of flagella gene expression in the opportunistic bacterial pathogen pseudomonas aeruginosa. homologs of fleq are present in all pseudomonas species and in many polarly flagellated gamma proteobacteria. cyclic diguanosine monophosphate (c-di-gmp) is a second messenger that controls the transition between planktonic and biofilm modes of growth in bacteria in response to diverse environmen ...201324167275
quantitative and qualitative impact of hospital effluent on dissemination of the integron pool.there is increasing evidence that human activity, and especially the resulting effluent, has a major role in the dissemination of bacterial antibiotic-resistance determinants in the environment. hospitals are the major antibiotic consumers and thus facilitate the spread of antibiotic resistance. questions are increasingly being raised about the management of hospital effluents, but their involvement in antibiotic-resistance dissemination has never been assessed. integrons are a paradigm of genet ...201324152716
quantitative and qualitative impact of hospital effluent on dissemination of the integron pool.there is increasing evidence that human activity, and especially the resulting effluent, has a major role in the dissemination of bacterial antibiotic-resistance determinants in the environment. hospitals are the major antibiotic consumers and thus facilitate the spread of antibiotic resistance. questions are increasingly being raised about the management of hospital effluents, but their involvement in antibiotic-resistance dissemination has never been assessed. integrons are a paradigm of genet ...201324152716
rapidly evolving r genes in diverse grass species confer resistance to rice blast disease.we show that the genomes of maize, sorghum, and brachypodium contain genes that, when transformed into rice, confer resistance to rice blast disease. the genes are resistance genes (r genes) that encode proteins with nucleotide-binding site (nbs) and leucine-rich repeat (lrr) domains (nbs-lrr proteins). by using criteria associated with rapid molecular evolution, we identified three rapidly evolving r-gene families in these species as well as in rice, and transformed a randomly chosen subset of ...201324145399
cis-2-dodecenoic acid signal modulates virulence of pseudomonas aeruginosa through interference with quorum sensing systems and t3ss.cis-2-dodecenoic acid (bdsf) is well known for its important functions in intraspecies signaling in burkholderia cenocepacia. previous work has also established an important role of bdsf in interspecies and inter-kingdom communications. it was identified that bdsf modulates virulence of pseudomonas aeruginosa. however, how bdsf interferes with virulence of p. aeruginosa is still not clear.201324134835
ehrlichia moonlighting effectors and interkingdom interactions with the mononuclear phagocyte.ehrlichia chaffeensis is an obligately intracellular gram negative bacterium with a small genome that thrives in mammalian mononuclear phagocytes by exploiting eukaryotic processes. herein, we discuss the latest findings on moonlighting tandem repeat protein effectors and their secretion mechanisms, and novel molecular interkingdom interactions that provide insight into the intracellular pathobiology of ehrlichiae.201324141087
comparative study of soxr activation by redox-active compounds.soxr from escherichia coli and related enterobacteria is activated by a broad range of redox-active compounds through oxidation or nitrosylation of its [2fe-2s] cluster. activated soxr then induces soxs, which subsequently activates more than 100 genes in response. in contrast, non-enteric soxrs directly activate their target genes in response to redox-active compounds that include endogenously produced metabolites. we compared the responsiveness of soxrs from streptomyces coelicolor (scsoxr), p ...201324112649
microbial synthesis of alka(e)nes.alka(e)nes are the predominant constituents of gasoline, diesel, and jet fuels. they can be produced naturally by a wide range of microorganisms. bio-alka(e)nes can be used as drop-in biofuels. to date, five microbial pathways that convert free fatty acids or fatty acid derivatives into alka(e)nes have been identified or reconstituted. the discoveries open a door to achieve microbial production of alka(e)nes with high efficiency. the modules derived from these alka(e)ne biosynthetic pathways can ...201325023719
the sensory histidine kinases tors and evgs tend to form clusters in escherichia coli cells.microorganisms use multiple two-component sensory systems to detect changes in their environment and elicit physiological responses. despite their wide spread and importance, the intracellular organization of two-component sensory proteins in bacteria remains little investigated. a notable exception is the well-studied clustering of the chemoreceptor-kinase complexes that mediate chemotaxis behaviour. however, these chemosensory complexes differ fundamentally from other systems, both structurall ...201324147062
antibacterial activity of nymphaea nouchali (burm. f) flower.the present work aimed to find out the antibacterial activity of nymphaea nouchali flower on human and plant pathogenic bacteria.201324099586
antimicrobial constituents of the leaves of mikania micrantha h. b. k.to isolate plant-derived compounds with antimicrobial activity from the leaves of mikania micrantha, to determine the compounds configuration, and to evaluate their antimicrobial activity against eight plant pathogenic fungi (exserohilum turcicum, colletotrichum lagenarium, pseudoperonispora cubensis, botrytis cirerea, rhizoctonia solani, phytophthora parasitica, fusarium solani, and pythium aphanidermatum,) and four plant pathogenic bacteria (gram negative bacteria: ralstonia dolaanacearum, xan ...201324098556
reduced virulence of the vibrio cholerae fadd mutant is due to induction of the extracytoplasmic stress response.vibrio cholerae, an important human intestinal pathogen, is responsible for the diarrheal disease cholera. the pathogenesis of v. cholerae is a highly coordinated process that involves diverse regulatory factors. it has recently been demonstrated that disruption of the v. cholerae fadd gene, encoding a long-chain fatty acyl coenzyme a (acyl-coa) ligase, drastically reduces expression of the major virulence genes and in vivo lethality of this important human pathogen. this effect was due to reduc ...201323918781
the putative enoyl-coenzyme a hydratase dspi is required for production of the pseudomonas aeruginosa biofilm dispersion autoinducer cis-2-decenoic acid.in the present study, we report the identification of a putative enoyl-coenzyme a (coa) hydratase/isomerase that is required for synthesis of the biofilm dispersion autoinducer cis-2-decenoic acid in the human pathogen pseudomonas aeruginosa. the protein is encoded by pa14_54640 (pa0745), named dspi for dispersion inducer. the gene sequence for this protein shows significant homology to rpff in xanthomonas campestris. inactivation of dspi was shown to abolish biofilm dispersion autoinduction in ...201323935049
progress in cultivation-independent phyllosphere microbiology.most microorganisms of the phyllosphere are nonculturable in commonly used media and culture conditions, as are those in other natural environments. this review queries the reasons for their 'noncultivability' and assesses developments in phyllospere microbiology that have been achieved cultivation independently over the last 4 years. analyses of total microbial communities have revealed a comprehensive microbial diversity. 16s rrna gene amplicon sequencing and metagenomic sequencing were applie ...201324003903
progress in cultivation-independent phyllosphere microbiology.most microorganisms of the phyllosphere are nonculturable in commonly used media and culture conditions, as are those in other natural environments. this review queries the reasons for their 'noncultivability' and assesses developments in phyllospere microbiology that have been achieved cultivation independently over the last 4 years. analyses of total microbial communities have revealed a comprehensive microbial diversity. 16s rrna gene amplicon sequencing and metagenomic sequencing were applie ...201324003903
ultimate system for rapid assembly of customized tal effectors.engineered tal-effector nucleases (talens) and tale-based constructs have become powerful tools for eukaryotic genome editing. although many methods have been reported, it remains a challenge for the assembly of designer-based tale repeats in a fast, precise and cost-effective manner. we present an ultimate (user-based ligation mediated assembly of tal effector) system for speedy and accurate assembly of customized tale constructs. this method takes advantage of uracil-specific excision reagent ...201324228087
cell wall degrading enzyme induced rice innate immune responses are suppressed by the type 3 secretion system effectors xopn, xopq, xopx and xopz of xanthomonas oryzae pv. oryzae.innate immune responses are induced in plants and animals through perception of damage associated molecular patterns. these immune responses are suppressed by pathogens during infection. a number of studies have focussed on identifying functions of plant pathogenic bacteria that are involved in suppression of pathogen associated molecular pattern induced immune responses. in comparison, there is very little information on functions used by plant pathogens to suppress damage associated molecular ...201324086651
response of high-risk of recurrence/progression bladder tumours expressing sialyl-tn and sialyl-6-t to bcg immunotherapy.high risk of recurrence/progression bladder tumours is treated with bacillus calmette-guérin (bcg) immunotherapy after complete resection of the tumour. approximately 75% of these tumours express the uncommon carbohydrate antigen sialyl-tn (tn), a surrogate biomarker of tumour aggressiveness. such changes in the glycosylation of cell-surface proteins influence tumour microenvironment and immune responses that may modulate treatment outcome and the course of disease. the aim of this work is to de ...201324064971
the transcriptional regulator np20 is the zinc uptake regulator in pseudomonas aeruginosa.zinc is essential for all bacteria, but excess amounts of the metal can have toxic effects. to address this, bacteria have developed tightly regulated zinc uptake systems, such as the znuabc zinc transporter which is regulated by the fur-like zinc uptake regulator (zur). in pseudomonas aeruginosa, a zur protein has yet to be identified experimentally, however, sequence alignment revealed that the zinc-responsive transcriptional regulator np20, encoded by np20 (pa5499), shares high sequence ident ...201324086521
the methionine sulfoxide reduction system: selenium utilization and methionine sulfoxide reductase enzymes and their functions.selenium is utilized in the methionine sulfoxide reduction system that occurs in most organisms. methionine sulfoxide reductases (msrs), msra and msrb, are the enzymes responsible for this system. msrs repair oxidatively damaged proteins, protect against oxidative stress, and regulate protein function, and have also been implicated in the aging process. selenoprotein forms of msrs containing selenocysteine (sec) at the catalytic site are found in bacteria, algae, and animals.201323198996
diversity and antimicrobial properties of lactic acid bacteria isolated from rhizosphere of olive trees and desert truffles of tunisia.a total of 119 lactic acid bacteria (lab) were isolated, by culture-dependant method, from rhizosphere samples of olive trees and desert truffles and evaluated for different biotechnological properties. using the variability of the intergenic spacer 16s-23s and 16s rrna gene sequences, the isolates were identified as the genera lactococcus, pediococcus, lactobacillus, weissella, and enterococcus. all the strains showed proteolytic activity with variable rates 42% were eps producers, while only 1 ...201324151598
verticillium suppression is associated with the glucosinolate composition of arabidopsis thaliana leaves.the soil-borne fungal pathogen verticillium longisporum is able to penetrate the root of a number of plant species and spread systemically via the xylem. fumigation of verticillium contaminated soil with brassica green manure is used as an environmentally friendly method for crop protection. here we present a study focused on the potential role of glucosinolates and their breakdown products of the model plant arabidopsis thaliana in suppressing growth of v. longisporum. for this purpose we analy ...201324039726
predicting promoters targeted by tal effectors in plant genomes: from dream to reality. 201324027573
stenotrophomonas maltophilia encodes a type ii protein secretion system that promotes detrimental effects on lung epithelial cells.the gram-negative bacterium stenotrophomonas maltophilia is increasingly identified as a multidrug-resistant pathogen, being associated with pneumonia, among other infections. despite this increasing clinical problem, the genetic and molecular basis of s. maltophilia virulence is quite minimally defined. we now report that strain k279a, the first clinical isolate of s. maltophilia to be sequenced, encodes a functional type ii protein secretion (t2s) system. indeed, mutants of k279a that contain ...201323774603
utilization of heme as an iron source by marine alphaproteobacteria in the roseobacter clade.the bioavailability and utilization of porphyrin-bound iron, specifically heme, by marine microorganisms have rarely been examined. this study used ruegeria sp. strain trichch4b as a model organism to study heme acquisition by a member of the roseobacter clade. analogs of known heme transporter proteins were found within the ruegeria sp. trichch4b genome. the identified heme uptake and utilization system appears to be functional, as the heme genes were upregulated under iron stress, the bacteriu ...201323872569
calcarides a-e, antibacterial macrocyclic and linear polyesters from a calcarisporium strain.bioactive compounds were detected in crude extracts of the fungus, calcarisporium sp. kf525, which was isolated from german wadden sea water samples. purification of the metabolites from the extracts yielded the five known polyesters, 15g256α, α-2, β, β-2 and π (1-5), and five new derivatives thereof, named calcarides a-e (6-10). the chemical structures of the isolated compounds were elucidated on the basis of one- and two-dimensional nmr spectroscopy supported by uv and hresims data. the compou ...201323994907
the molecular mechanisms of allosteric mutations impairing mepr repressor function in multidrug-resistant strains of staphylococcus aureus.overexpression of the staphylococcus aureus multidrug efflux pump mepa confers resistance to a wide variety of antimicrobials. mepa expression is controlled by marr family member mepr, which represses mepa and autorepresses its own production. mutations in mepr are a primary cause of mepa overexpression in clinical isolates of multidrug-resistant s. aureus. here, we report crystal structures of three multidrug-resistant mepr variants, which contain the single-amino-acid substitution a103v, f27l, ...201323982071
development of microencapsulation delivery system for long-term preservation of probiotics as biotherapeutics agent.the administration of probiotic bacteria for health benefit has rapidly expanded in recent years, with a global market worth $32.6 billion predicted by 2014. the oral administration of most of the probiotics results in the lack of ability to survive in a high proportion of the harsh conditions of acidity and bile concentration commonly encountered in the gastrointestinal tract of humans. providing probiotic living cells with a physical barrier against adverse environmental conditions is therefor ...201324027760
bacterial second messengers, cgmp and c-di-gmp, in a quest for regulatory dominance. 201323963313
the structure of amylosucrase from deinococcus radiodurans has an unusual open active-site topology.amylosucrases (ases) catalyze the formation of an α-1,4-glucosidic linkage by transferring a glucosyl unit from sucrose onto an acceptor α-1,4-glucan. to date, several ligand-bound crystal structures of wild-type and mutant ases from neisseria polysaccharea and deinococcus geothermalis have been solved. these structures all display a very similar overall conformation with a deep pocket leading to the site for transglucosylation, subsite -1. this has led to speculation on how sucrose enters the a ...201323989143
structure of the avrbs3-dna complex provides new insights into the initial thymine-recognition mechanism.transcription activator-like effectors contain a dna-binding domain organized in tandem repeats. the repeats include two adjacent residues known as the repeat variable di-residue, which recognize a single base pair, establishing a direct code between the dipeptides and the target dna. this feature suggests this scaffold as an excellent candidate to generate new protein-dna specificities for biotechnological applications. here, the crystal structure of avrbs3 (residues 152-895, molecular mass 82  ...201323999294
candida albicans and enterococcus faecalis in the gut: synergy in commensalism?the fungus candida albicans and the gram-positive bacterium enterococcus faecalis are both normal residents of the human gut microbiome and cause opportunistic disseminated infections in immunocompromised individuals. using a nematode infection model, we recently showed that co-infection resulted in less pathology and less mortality than infection with either species alone and this was partly explained by an interkingdom signaling event in which a bacterial-derived product inhibits hyphal morpho ...201323941906
an s-type anion channel slac1 is involved in cryptogein-induced ion fluxes and modulates hypersensitive responses in tobacco by-2 cells.pharmacological evidence suggests that anion channel-mediated plasma membrane anion effluxes are crucial in early defense signaling to induce immune responses and hypersensitive cell death in plants. however, their molecular bases and regulation remain largely unknown. we overexpressed arabidopsis slac1, an s-type anion channel involved in stomatal closure, in cultured tobacco by-2 cells and analyzed the effect on cryptogein-induced defense responses including fluxes of cl(-) and other ions, pro ...201323950973
development of quorum-based anti-virulence therapeutics targeting gram-negative bacterial pathogens.quorum sensing is a cell density-dependent signaling phenomenon used by bacteria for coordination of population-wide phenotypes, such as expression of virulence genes, antibiotic resistance and biofilm formation. lately, disruption of bacterial communication has emerged as an anti-virulence strategy with enormous therapeutic potential given the increasing incidences of drug resistance in pathogenic bacteria. the quorum quenching therapeutic approach promises a lower risk of resistance developmen ...201323939429
lacinilene c 7-methyl ether.the title compound, c16h20o3 [systematic name: 1-hy-droxy-7-meth-oxy-1,6-dimethyl-4-(propan-2-yl)naphthalen-2(1h)-one], is a sesquiterpene isolated from foliar tissues of the cotton plant and is of inter-est with respect to its anti-bacterial properties. its phenyl ring is ideally planar, and the maximum of deviation in the second ring is 0.386 (3) å. the hy-droxy group and the methyl group are oriented in an equatorial fashion and axial, respectively, to the second ring. in the crystal, inversi ...201324427033
functional consequences of substitution mutations in mepr, a repressor of the staphylococcus aureus mepa multidrug efflux pump gene.the expression of mepa, encoding the staphylococcus aureus mepa multidrug efflux protein, is repressed by the marr homologue mepr. mepr dimers bind differently to operators upstream of mepr and mepa, with affinity being greatest at the mepa operator. mepr substitution mutations may result in mepa overexpression, with a103v most common in clinical strains. evaluation of the functional consequences of this and other mepr substitutions using a lacz reporter gene assay revealed markedly reduced repr ...201323749979
characterization of structural stability of palm oil esters-based nanocosmeceuticals loaded with tocotrienol.palm oil esters (poes) are esters derived from palm oil and oleyl alcohol have great potential in the cosmetic and pharmaceutical industries due to the excellent wetting behavior of the esters without the oily feel. the role of oil-in-water nanoemulsions loaded with tocotrienol sedimentation behavior was studied. lumifuge® 116 particle separation analyzer was used to investigate the sedimentation behavior of poes/tocotrienol/xanthan gum nanoemulsion system during centrifugation. analyzing the se ...201324059593
molecular phylogeny, homology modeling, and molecular dynamics simulation of race-specific bacterial blight disease resistance protein (xa5) of rice: a comparative agriproteomics approach.rice (oryza sativa l.), a model plant belonging to the family poaceae, is a staple food for a majority of the people worldwide. grown in the tropical and subtropical regions of the world, this important cereal crop is under constant and serious threat from both biotic and abiotic stresses. among the biotic threats, xanthomonas oryzae pv. oryzae, causing the damaging bacterial blight disease in rice, is a prominent pathogen. the xa5 gene in the host plant rice confers race-specific resistance to ...201323758479
functional characterization of burkholderia pseudomallei trimeric autotransporters.burkholderia pseudomallei is a tier 1 select agent and the causative agent of melioidosis, a severe and often fatal disease with symptoms ranging from acute pneumonia and septic shock to a chronic infection characterized by abscess formation in the lungs, liver, and spleen. autotransporters (ats) are exoproteins belonging to the type v secretion system family, with many playing roles in pathogenesis. the genome of b. pseudomallei strain 1026b encodes nine putative trimeric at proteins, of which ...201323716608
crystal structure of the n-acetyltransferase domain of human n-acetyl-l-glutamate synthase in complex with n-acetyl-l-glutamate provides insights into its catalytic and regulatory mechanisms.n-acetylglutamate synthase (nags) catalyzes the conversion of accoa and l-glutamate to coa and n-acetyl-l-glutamate (nag), an obligate cofactor for carbamyl phosphate synthetase i (cpsi) in the urea cycle. nags deficiency results in elevated levels of plasma ammonia which is neurotoxic. we report herein the first crystal structure of human nags, that of the catalytic n-acetyltransferase (hnat) domain with n-acetyl-l-glutamate bound at 2.1 å resolution. functional studies indicate that the hnat d ...201323894642
a cyclic gmp-dependent signalling pathway regulates bacterial phytopathogenesis.cyclic guanosine 3',5'-monophosphate (cyclic gmp) is a second messenger whose role in bacterial signalling is poorly understood. a genetic screen in the plant pathogen xanthomonas campestris (xcc) identified that xc_0250, which encodes a protein with a class iii nucleotidyl cyclase domain, is required for cyclic gmp synthesis. purified xc_0250 was active in cyclic gmp synthesis in vitro. the linked gene xc_0249 encodes a protein with a cyclic mononucleotide-binding (cnmp) domain and a ggdef digu ...201323881098
the dsf quorum sensing system controls the positive influence of stenotrophomonas maltophilia on plants.the interaction of the gram-negative bacterium stenotrophomonas maltophilia with eukaryotes can improve overall plant growth and health, but can also cause opportunistic infections in humans. while the quorum sensing molecule dsf (diffusible signal factor) is responsible for the regulation of phenotypes in pathogenic stenotrophomonas, up until now, no beneficial effects were reported to be controlled by it. our objective was to study the function of dsf in the plant growth promoting model strain ...201323874407
interaction between extracellular lipase lipa and the polysaccharide alginate of pseudomonas aeruginosa.as an opportunistic human pathogen pseudomonas aeruginosa is able to cause acute and chronic infections. the biofilm mode of life significantly contributes to the growth and persistence of p. aeruginosa during an infection process and mediates the pathogenicity of the bacterium. within a biofilm mucoid strains of p. aeruginosa simultaneously produce and secrete several hydrolytic enzymes and the extracellular polysaccharide alginate. the focus of the current study was the interaction between ext ...201323848942
genome sequences of three atypical xanthomonas campestris pv. campestris strains, cn14, cn15, and cn16.xanthomonas campestris pv. campestris is the causal agent of black rot on brassicaceae. the draft genome sequences of three strains (cn14, cn15, and cn16) that are highly aggressive on arabidopsis have been determined. these genome sequences present an unexpected genomic diversity in x. campestris pv. campestris, which will be valuable for comparative analyses.201323846270
structure of n-acetyl-l-glutamate synthase/kinase from maricaulis maris with the allosteric inhibitor l-arginine bound.maricaulis maris n-acetylglutamate synthase/kinase (mmnags/k) catalyzes the first two steps in l-arginine biosynthesis and has a high degree of sequence and structural homology to human n-acetylglutamate synthase, a regulator of the urea cycle. the synthase activity of both mmnags/k and human nags are regulated by l-arginine, although l-arginine is an allosteric inhibitor of mmnags/k, but an activator of human nags. to investigate the mechanism of allosteric inhibition of mmnags/k by l-arginine, ...201323850694
the in vitro anti-acne activity of two unani drugs.acne is the most common disorder treated by dermatologists. as many as 80-90% of all adolescents have some type of acne and 30% of them require medical treatment. it is an inflammatory disease of the pilosebaceous unit characterized by the formation of open and closed comedones, papules, pustules, nodules, and cysts.201325161328
dissecting the metal selectivity of merr monovalent metal ion sensors in salmonella.two homologous transcription factors, cuer and gols, that belong to the merr metalloregulatory family are responsible for salmonella cu and au sensing and resistance, respectively. they share similarities not only in their sequences, but also in their target transcription binding sites. while cuer responds similarly to au, ag, or cu to induce the expression of its target genes, gols shows higher activation by au than by ag or cu. we showed that the ability of gols to distinguish au from cu resid ...201323645605
current challenges in bacterial transcriptomics.over the past decade or so, dramatic developments in our ability to experimentally determine the content and function of genomes have taken place. in particular, next-generation sequencing technologies are now inspiring a new understanding of bacterial transcriptomes on a global scale. in bacterial cells, whole-transcriptome studies have not received attention, owing to the general view that bacterial genomes are simple. however, several recent rna sequencing results are revealing unexpected lev ...201323843773
a simple and efficient method for assembling tale protein based on plasmid library.dna binding domain of the transcription activator-like effectors (tales) from xanthomonas sp. consists of tandem repeats that can be rearranged according to a simple cipher to target new dna sequences with high dna-binding specificity. this technology has been successfully applied in varieties of species for genome engineering. however, assembling long tale tandem repeats remains a big challenge precluding wide use of this technology. although several new methodologies for efficiently assembling ...201323840477
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