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bioactivity of diterpens from the ethyl acetate extract of kingiodendron pinnatum rox. hams.kingiodendron pinnatum rox. hams. is an endangered medicinal plant used in gonorrhoe, catarrhal conditions of genito-urinary and respiratory tracts. the scientific and pharmacological formulation of k. pinnatum has not been established so far though it is being traditionally used by tribes of the region.201627695270
a non canonical subtilase attenuates the transcriptional activation of defence responses in arabidopsis thaliana.proteases play crucial physiological functions in all organisms by controlling the lifetime of proteins. here, we identified an atypical protease of the subtilase family [sbt5.2(b)] that attenuates the transcriptional activation of plant defence independently of its protease activity. the sbt5.2 gene produces two distinct transcripts encoding a canonical secreted subtilase [sbt5.2(a)] and an intracellular protein [sbt5.2(b)]. concomitant to sbt5.2(a) downregulation, sbt5.2(b) expression is induc ...201627685353
map-based cloning and characterization of the bph18 gene from wild rice conferring resistance to brown planthopper (bph) insect pest.brown planthopper (bph) is a phloem sap-sucking insect pest of rice which causes severe yield loss. we cloned the bph18 gene from the bph-resistant introgression line derived from the wild rice species oryza australiensis. map-based cloning and complementation test revealed that the bph18 encodes cc-nbs-nbs-lrr protein. bph18 has two nbs domains, unlike the typical nbs-lrr proteins. the bph18 promoter::gus transgenic plants exhibited strong gus expression in the vascular bundles of the leaf shea ...201627682162
the arabidopsis cerk1-associated kinase pbl27 connects chitin perception to mapk activation.perception of microbe-associated molecular patterns by host cell surface pattern recognition receptors (prrs) triggers the intracellular activation of mitogen-activated protein kinase (mapk) cascades. however, it is not known how prrs transmit immune signals to mapk cascades in plants. here, we identify a complete phospho-signaling transduction pathway from prr-mediated pathogen recognition to mapk activation in plants. we found that the receptor-like cytoplasmic kinase pbl27 connects the chitin ...201627679653
quantitative proteomics reveals the defense response of wheat against puccinia striiformis f. sp. tritici.wheat stripe rust, caused by puccinia striiformis f. sp. tritici (pst), is considered one of the most aggressive diseases to wheat production. in this study, we used an itraq-based approach for the quantitative proteomic comparison of the incompatible pst race cyr23 in infected and non-infected leaves of the wheat cultivar suwon11. a total of 3,475 unique proteins were identified from three key stages of interaction (12, 24, and 48 h post-inoculation) and control groups. quantitative analysis sh ...201627678307
a small cysteine-rich protein from the asian soybean rust fungus, phakopsora pachyrhizi, suppresses plant immunity.the asian soybean rust fungus, phakopsora pachyrhizi, is an obligate biotrophic pathogen causing severe soybean disease epidemics. molecular mechanisms by which p. pachyrhizi and other rust fungi interact with their host plants are poorly understood. the genomes of all rust fungi encode many small, secreted cysteine-rich proteins (sscrp). while these proteins are thought to function within the host, their roles are completely unknown. here, we present the characterization of p. pachyrhizi effect ...201627676173
old concepts, new molecules and current approaches applied to the bacterial nucleotide signalling field.signalling nucleotides are key molecules that help bacteria to rapidly coordinate cellular pathways and adapt to changes in their environment. during the past 10 years, the nucleotide signalling field has seen much excitement, as several new signalling nucleotides have been discovered in both eukaryotic and bacterial cells. the fields have since advanced quickly, aided by the development of important tools such as the synthesis of modified nucleotides, which, combined with sensitive mass spectro ...201627672152
trigger phosphodiesterases as a novel class of c-di-gmp effector proteins.the bacterial second messenger c-di-gmp controls bacterial biofilm formation, motility, cell cycle progression, development and virulence. it is synthesized by diguanylate cyclases (with ggdef domains), degraded by specific phosphodiesterases (pdes, with eal of hd-gyp domains) and sensed by a wide variety of c-di-gmp-binding effectors that control diverse targets. c-di-gmp-binding effectors can be riboswitches as well as proteins with highly diverse structures and functions. the latter include ' ...201627672149
multilocus variable number of tandem repeat analysis reveals multiple introductions in spain of xanthomonas arboricola pv. pruni, the causal agent of bacterial spot disease of stone fruits and almond.xanthomonas arboricola pv. pruni is the causal agent of the bacterial spot disease of stone fruits, almond and some ornamental prunus species. in spain it was first detected in 2002 and since then, several outbreaks have occurred in different regions affecting mainly japanese plum, peach and almond, both in commercial orchards and nurseries. as the origin of the introduction(s) was unknown, we have assessed the genetic diversity of 239 x. arboricola pv. pruni strains collected from 11 spanish pr ...201627669415
calecrk-s.5, a pepper l-type lectin receptor kinase gene, confers broad-spectrum resistance by activating priming.in arabidopsis, several l-type lectin receptor kinases (lecrks) have been identified as putative immune receptors. however, to date, there have been few analyses of lecrks in crop plants. virus-induced gene silencing of calecrk-s.5 verified the role of calecrk-s.5 in broad-spectrum resistance. compared with control plants, calecrk-s.5-silenced plants showed reduced hypersensitive response, reactive oxygen species burst, secondary metabolite production, mitogen-activated protein kinase activation ...201627647723
(1)h, (13)c, and (15)n resonance assignments and secondary structure information for methylobacterium extorquens pqqd and the complex of pqqd with pqqa.the ribosomally synthesized and post-translationally modified peptide (ripp), pyrroloquinoline quinone (pqq), is a dehydrogenase cofactor synthesized by, but not exclusively used by, certain prokaryotes. ripps represent a rapidly expanding and diverse class of natural products-many of which have therapeutic potential-and the biosynthetic pathways for these are gaining attention. five gene products from the pqq operon (pqqa, pqqb, pqqc, pqqd, and pqqe) are essential for pqq biosynthesis. the subs ...201627638737
bioprospecting red sea coastal ecosystems for culturable microorganisms and their antimicrobial potential.microorganisms that inhabit unchartered unique soil such as in the highly saline and hot red sea lagoons on the saudi arabian coastline, represent untapped sources of potentially new bioactive compounds. in this study, a culture-dependent approach was applied to three types of sediments: mangrove mud (mn), microbial mat (mm), and barren soil (bs), collected from rabigh harbor lagoon (rhl) and al-kharrar lagoon (akl). the isolated bacteria were evaluated for their potential to produce bioactive c ...201627626430
xanthomonas campestris attenuates virulence by sensing light through a bacteriophytochrome photoreceptor.phytochromes constitute a major photoreceptor family found in plants, algae, fungi, and prokaryotes, including pathogens. here, we report that xanthomonas campestris pv. campestris (xcc), the causal agent of black rot disease which affects cruciferous crops worldwide, codes for a functional bacteriophytochrome (xccbphp). xccbphp possesses an n-terminal pas2-gaf-phy photosensory domain triad and a c-terminal pas9 domain as its output module. our results show that illumination of xcc, prior to pla ...201627621284
structural differences in gut bacteria communities in developmental stages of natural populations of lutzomyia evansi from colombia's caribbean coast.lutzomyia evansi, a phlebotomine insect endemic to colombia's caribbean coast, is considered to be the main vector of visceral and cutaneous leishmaniasis in the region. although insects of this species can harbor pathogenic and non-pathogenic microorganisms in their intestinal microbiota, there is little information available about the diversity of gut bacteria present in lutzomyia evansi. in this study, conventional microbiological methods and molecular tools were used to assess the compositio ...201627618991
the proteasome acts as a hub for plant immunity and is targeted by pseudomonas type iii effectors.recent evidence suggests that the ubiquitin-proteasome system is involved in several aspects of plant immunity and that a range of plant pathogens subvert the ubiquitin-proteasome system to enhance their virulence. here, we show that proteasome activity is strongly induced during basal defense in arabidopsis (arabidopsis thaliana). mutant lines of the proteasome subunits rpt2a and rpn12a support increased bacterial growth of virulent pseudomonas syringae pv tomato dc3000 (pst) and pseudomonas sy ...201627613851
a self-inducible heterologous protein expression system in escherichia coli.escherichia coli is an important experimental, medical and industrial cell factory for recombinant protein production. the inducible lac promoter is one of the most commonly used promoters for heterologous protein expression in e. coli. isopropyl-β-d-thiogalactoside (iptg) is currently the most efficient molecular inducer for regulating this promoter's transcriptional activity. however, limitations have been observed in large-scale and microplate production, including toxicity, cost and culture ...201627611846
genomic characterization of the novel aeromonas hydrophila phage ahp1 suggests the derivation of a new subgroup from phikmv-like family.aeromonas hydrophila is an opportunistic pathogenic bacterium causing diseases in human and fish. the emergence of multidrug-resistant a. hydrophila isolates has been increasing in recent years. in this study, we have isolated a novel virulent podophage of a. hydrophila, designated as ahp1, from waste water. ahp1 has a rapid adsorption (96% adsorbed in 2 min), a latent period of 15 min, and a burst size of 112 pfu per infected cell. at least eighteen ahp1 virion proteins were visualized in sds-p ...201627603936
pseudomonas fluorescens filamentous hemagglutinin, an iron-regulated protein, is an important virulence factor that modulates bacterial pathogenicity.pseudomonas fluorescens is a common bacterial pathogen to a wide range of aquaculture animals including various species of fish. in this study, we employed proteomic analysis and identified filamentous hemagglutinin (fha) as an iron-responsive protein secreted by tss, a pathogenic p. fluorescens isolate. in vitro study showed that compared to the wild type, the fha mutant tssfha (i) exhibited a largely similar vegetative growth profile but significantly retarded in the ability of biofilm growth ...201627602029
crystal structure of the yajq-family protein xc_3703 from xanthomonas campestris pv. campestris.as an important bacterial second messenger, bis-(3',5')-cyclic diguanylate (cyclic di-gmp or c-di-gmp) has been implicated in numerous biological activities, including biofilm formation, motility, survival and virulence. these processes are manipulated by the binding of c-di-gmp to its receptors. xc_3703 from the plant pathogen xanthomonas campestris pv. campestris, which belongs to the yajq family of proteins, has recently been identified as a potential c-di-gmp receptor. xc_3703, together with ...201627599864
xanthomonas campestris fabh is required for branched-chain fatty acid and dsf-family quorum sensing signal biosynthesis.xanthomonas campestris pv. campestris (xcc), a gram-negative phytopathogenic bacterium, causes black rot disease of cruciferous vegetables. although xcc has a complex fatty acid profile comprised of straight-chain fatty acids and branched-chain fatty acids (bcfas), and encodes a complete set of genes required for fatty acid synthesis, there is still little known about the mechanism of bcfa synthesis. we reported that expression of xcc fabh restores the growth of ralstonia solanacearum fabh mutan ...201627595587
interaction network and mass spectrometry data of xanthomonas citri subsp. citri surface proteins from differential proteomic analysis of infectious and non-infectious cells.here we provide the mass-spectrometry and in silico interaction network dataset of proteins identified on our research article on surface proteomic analysis from xanthomonas citri subsp. citri (xac) cells grown in vivo (infectious) and in vitro (non-infectious, control) by 2d-dige approach. fluorescence labeling of proteins were performed on intact cells followed by cellular lysis and labeled spots from 2d gel differing in abundance between the two conditions (anova, p-value<0.05) were analyzed ...201627595129
the intervening sequence of coxiella burnetii: characterization and evolution.the intervening sequence (ivs) of coxiella burnetii, the agent of q fever, is a 428-nt selfish genetic element located in helix 45 of the precursor 23s rrna. the ivs element, in turn, contains an orf that encodes a hypothetical ribosomal s23 protein (s23p). although s23p can be synthesized in vitro in the presence of an engineered e. coli promoter and ribosome binding site, results suggest that the protein is not synthesized in vivo. in spite of a high degree of ivs conservation among different ...201627595093
peroxiredoxin catalysis at atomic resolution.peroxiredoxins (prxs) are ubiquitous cysteine-based peroxidases that guard cells against oxidative damage, are virulence factors for pathogens, and are involved in eukaryotic redox regulatory pathways. we have analyzed catalytically active crystals to capture atomic resolution snapshots of a prxq subfamily enzyme (from xanthomonas campestris) proceeding through thiolate, sulfenate, and sulfinate species. these analyses provide structures of unprecedented accuracy for seeding theoretical studies, ...201627594682
how auxin and cytokinin phytohormones modulate root microbe interactions.a large range of microorganisms can associate with plants, resulting in neutral, friendly or hostile interactions. the ability of plants to recognize compatible and incompatible microorganisms and to limit or promote their colonization is therefore crucial for their survival. elaborated communication networks determine the degree of association between the host plant and the invading microorganism. central to these regulations of plant microbe interactions, phytohormones modulate microorganism p ...201627588025
high-quality draft genome sequences of two xanthomonas pathotype strains infecting aroid plants.we present here the draft genome sequences of bacterial pathogens of the araceae family, xanthomonas axonopodis pv. dieffenbachiae lmg 695 and xanthomonas campestris pv. syngonii lmg 9055, differing in host range. a comparison between genome sequences will help understand the mechanisms involved in tissue specificity and adaptation to host plants.201627587819
exploiting indigenous knowledge of subsistence farmers' for the management and conservation of enset (ensete ventricosum (welw.) cheesman) (musaceae family) diversity on-farm.enset (ensete ventricosum (welw.) cheesman) belongs to the order sctaminae, the family musaceae. the musaceae family is subdivided into the genera musa and ensete. enset is an important staple crop for about 20 million people in the country. recent publications on enset ethnobotany are insignificant when compared to the diverse ethnolingustic communities in the country. hence, this paper try to identify and document wealth of indigenous knowledge associated with the distribution, diversity, and ...201627586388
cloning, expression, and characterization of a novel thermophilic monofunctional catalase from geobacillus sp. chb1.catalases are widely used in many scientific areas. a catalase gene (kat) from geobacillus sp. chb1 encoding a monofunctional catalase was cloned and recombinant expressed in escherichia coli (e. coli), which was the first time to clone and express this type of catalase of genus geobacillus strains as far as we know. this kat gene was 1,467 bp in length and encoded a catalase with 488 amino acid residuals, which is only 81% similar to the previously studied bacillus sp. catalase in terms of amin ...201627579320
nucleotide binding by the widespread high-affinity cyclic di-gmp receptor mshen domain.c-di-gmp is a bacterial second messenger regulating various cellular functions. many bacteria contain c-di-gmp-metabolizing enzymes but lack known c-di-gmp receptors. recently, two mshe-type atpases associated with bacterial type ii secretion system and type iv pilus formation were shown to specifically bind c-di-gmp. here we report crystal structure of the mshe n-terminal domain (mshen1-145) from vibrio cholerae in complex with c-di-gmp at a 1.37 å resolution. this structure reveals a unique c- ...201627578558
regulation of organic hydroperoxide stress response by two ohrr homologs in pseudomonas aeruginosa.pseudomonas aeruginosa ohrr and ospr are gene homologs encoding oxidant sensing transcription regulators. ospr is known to regulate gpx, encoding a glutathione peroxidase, while ohrr regulates the expression of ohr that encodes an organic peroxide specific peroxiredoxin. here, we show that ospr mediated gpx expression, like ohrr and ohr, specifically responds to organic hydroperoxides as compared to hydrogen peroxide and superoxide anion. furthermore, the regulation of these two systems is inter ...201627560944
the plant cell wall: a complex and dynamic structure as revealed by the responses of genes under stress conditions.the plant cell wall has a diversity of functions. it provides a structural framework to support plant growth and acts as the first line of defense when the plant encounters pathogens. the cell wall must also retain some flexibility, such that when subjected to developmental, biotic, or abiotic stimuli it can be rapidly remodeled in response. genes encoding enzymes capable of synthesizing or hydrolyzing components of the plant cell wall show differential expression when subjected to different str ...201627559336
draft genome sequences of three xanthomonas translucens pathovar reference strains (pv. arrhenatheri, pv. poae and pv. phlei) with different specificities for forage grasses.as causal agents of bacterial wilt in pastures and meadows, bacteria of the species xanthomonas translucens are a serious issue in forage grass production. so far, only little is known about host-pathogen interactions at the molecular level and the lack of comprehensive genome data impeded targeted breeding strategies towards resistant forage grass cultivars. here we announce the draft genome sequences of three grass-pathogenic xanthomonas translucens pathotype strains, i.e. pv. arrhenatheri lmg ...201627536340
two distinct mechanisms of transcriptional regulation by the redox sensor yodb.for bacteria, cysteine thiol groups in proteins are commonly used as thiol-based switches for redox sensing to activate specific detoxification pathways and restore the redox balance. among the known thiol-based regulatory systems, the marr/duf24 family regulators have been reported to sense and respond to reactive electrophilic species, including diamide, quinones, and aldehydes, with high specificity. here, we report that the prototypical regulator yodb of the marr/duf24 family from bacillus s ...201627531959
behind the lines-actions of bacterial type iii effector proteins in plant cells.pathogenicity of most gram-negative plant-pathogenic bacteria depends on the type iii secretion (t3s) system, which translocates bacterial effector proteins into plant cells. type iii effectors modulate plant cellular pathways to the benefit of the pathogen and promote bacterial multiplication. one major virulence function of type iii effectors is the suppression of plant innate immunity, which is triggered upon recognition of pathogen-derived molecular patterns by plant receptor proteins. type ...201627526699
antimicrobial profile of arthrobacter kerguelensis vl-rk_09 isolated from mango orchards.an actinobacterial strain vl-rk_09 having potential antimicrobial activities was isolated from a mango orchard in krishna district, andhra pradesh (india) and was identified as arthrobacter kerguelensis. the strain a. kerguelensis vl-rk_09 exhibited a broad spectrum of in vitro antimicrobial activity against bacteria and fungi. production of bioactive metabolites by the strain was the highest in modified yeast extract malt extract dextrose broth, as compared to other media tested. lactose (1%) a ...201627515463
nudix effectors: a common weapon in the arsenal of plant pathogens. 201627513453
grape cultivar and sap culture conditions affect the development of xylella fastidiosa phenotypes associated with pierce's disease.xylella fastidiosa is a xylem-limited bacterium in plant hosts and causes pierce's disease (pd) of grapevines, which differ in susceptibility according to the vitis species (spp.). in this work we compared x. fastidiosa biofilm formation and population dynamics when cultured in xylem saps from pd-susceptible and -resistant vitis spp. under different conditions. behaviors in a closed-culture system were compared to those in different sap-renewal cultures that would more closely mimic the physicoc ...201627508296
pea broth enhances the biocontrol efficacy of lysobacter capsici az78 by triggering cell motility associated with biogenesis of type iv pilus.bacterial cells can display different types of motility, due to the presence of external appendages such as flagella and type iv pili. to date, little information on the mechanisms involved in the motility of the lysobacter species has been available. recently, l. capsici az78, a biocontrol agent of phytopathogenic oomycetes, showed the ability to move on jellified pea broth. pea broth medium improved also the biocontrol activity of l. capsici az78 against plasmopara viticola under greenhouse co ...201627507963
cobalt(ii) complexes of sparfloxacin: characterization, structure, antimicrobial activity and interaction with dna and albumins.the cobalt(ii) complexes with the quinolone sparfloxacin (hsf) in the absence or presence of the nitrogen-donor heterocyclic ligands 2,2'-bipyridine (bipy), 1,10-phenanthroline (phen) or 2,2'-bipyridylamine (bipyam) were prepared and characterized physicochemically and spectroscopically. the crystal structures of complexes [co(sf)2(bipy)]∙3meoh∙2h2o and [co(sf)2(phen)]∙4meoh were determined by x-ray crystallography. the antimicrobial activity of the complexes was tested against four different mi ...201627501348
the arabidopsis protein phosphatase pp2c38 negatively regulates the central immune kinase bik1.plants recognize pathogen-associated molecular patterns (pamps) via cell surface-localized pattern recognition receptors (prrs), leading to prr-triggered immunity (pti). the arabidopsis cytoplasmic kinase bik1 is a downstream substrate of several prr complexes. how plant pti is negatively regulated is not fully understood. here, we identify the protein phosphatase pp2c38 as a negative regulator of bik1 activity and bik1-mediated immunity. pp2c38 dynamically associates with bik1, as well as with ...201627494702
toxicity of twenty-two plant essential oils against pathogenic bacteria of vegetables and mushrooms.asbtract toxicity of twenty-two essential oils to three bacterial pathogens in different horticultural systems: xanthomonas campestris pv. phaseoli (causing blight of bean), clavibacter michiganensis subsp. michiganensis (bacterial wilt and canker of tomato), and pseudomonas tolaasii (causal agent of bacterial brown blotch on cultivated mushrooms) was tested. control of bacterial diseases is very difficult due to antibiotic resistance and ineffectiveness of chemical products, to that essential o ...201627494458
identification and expression profiles of six transcripts encoding carboxylesterase protein in vitis flexuosa infected with pathogens.plants protect themselves from pathogen attacks via several mechanisms, including hypersensitive cell death. recognition of pathogen attack by the plant resistance gene triggers expression of carboxylesterase genes associated with hypersensitive response. we identified six transcripts of carboxylesterase genes, vitis flexuosa carboxylesterase 5585 (vfcxe5585), vfcxe12827, vfcxe13132, vfcxe17159, vfcxe18231, and vfcxe47674, which showed different expression patterns upon transcriptome analysis of ...201627493610
modification of bacterial effector proteins inside eukaryotic host cells.pathogenic bacteria manipulate their hosts by delivering a number of virulence proteins -called effectors- directly into the plant or animal cells. recent findings have shown that such effectors can suffer covalent modifications inside the eukaryotic cells. here, we summarize the recent reports where effector modifications by the eukaryotic machinery have been described. we restrict our focus on proteins secreted by the type iii or type iv systems, excluding other bacterial toxins. we describe t ...201627489796
dynamic light scattering of xanthan gum biopolymer in colloidal dispersion.the dynamical properties of nanogels of xanthan gum (xg) with hydrodynamic radius controlled in a size range from 5 nm to 35 nm, were studied at the different xg concentrations in water/sodium bis-2-ethylhexyl-sulfosuccinate (aot)/decane reverse micelles (rms) vs. mass fraction of nano-droplet (mfd) at w = 40, using dynamic light scattering (dls). the diffusion study of nanometer-sized droplets by dls technique indicated that enhancing concentration of the xg polysaccharide resulted in exchangin ...201627489730
surface immobilization of human arginase-1 with an engineered ice nucleation protein display system in e. coli.ice nucleation protein (inp) is frequently used as a surface anchor for protein display in gram-negative bacteria. here, male and tora signal peptides, and three charged polypeptides, 6×lys, 6×glu and 6×asp, were anchored to the n-terminus of truncated inp (inak-n) to improve its surface display efficiency for human arginase1 (arg1). our results indicated that the tora signal peptide increased the surface translocation of non-protein fused inak-n and human arg1 fused inak-n (inak-n/arg1) by 80.7 ...201627479442
biosynthesis of xanthan gum by xanthomonas campestris lrelp-1 using kitchen waste as the sole substrate.herein, we report the production of xanthan gum by fermentation using kitchen waste as the sole substrate. the kitchen waste was firstly pretreated by a simple hydrolysis method, after which the obtained kitchen waste hydrolysate was diluted with an optimal ratio 1:2. in a 5-l fermentor, the maximum xanthan production, reducing sugar conversion and utilization rates reached 11.73g/l, 67.07% and 94.82%, respectively. the kinetics of batch fermentation was also investigated. ft-ir and xrd characte ...201627474614
a host basal transcription factor is a key component for infection of rice by tale-carrying bacteria.transcription activator-like effectors (tales) are sequence-specific dna binding proteins found in a range of plant pathogenic bacteria, where they play important roles in host-pathogen interactions. however, it has been unclear how tales, after they have been injected into the host cells, activate transcription of host genes required for infection success. here, we show that the basal transcription factor iia gamma subunit tfiiaγ5 from rice is a key component for infection by the tale-carrying ...201627472897
two distinct cardiolipin synthases operate in agrobacterium tumefaciens.cardiolipin (cl) is a universal component of energy generating membranes. in most bacteria, it is synthesized via the condensation of two molecules phosphatidylglycerol (pg) by phospholipase d-type cardiolipin synthases (pld-type cls). in the plant pathogen and natural genetic engineer agrobacterium tumefaciens cl comprises up to 15% of all phospholipids in late stationary growth phase. a. tumefaciens harbors two genes, atu1630 (cls1) and atu2486 (cls2), coding for pld-type cls. heterologous exp ...201627472399
xanthan pyruvilation is essential for the virulence of xanthomonas campestris pv. campestris.xanthan, the main exopolysaccharide (eps) synthesized by xanthomonas spp., contributes to bacterial stress tolerance and enhances attachment to plant surfaces by helping in biofilm formation. therefore, xanthan is essential for successful colonization and growth in planta and has also been proposed to be involved in the promotion of pathogenesis by calcium ion chelation and, hence, in the suppression of the plant defense responses in which this cation acts as a signal. the aim of this work was t ...201627464764
dispersal of human and plant pathogens biofilms via nitric oxide donors at 4 °c.recent studies suggest that nitric oxide donors capable of manipulating nitric oxide-mediated signaling in bacteria could induce dispersal of biofilms. encased in extracellular polymeric substances, human and plant pathogens within biofilms are significantly more resistant to sanitizers. this is particularly a problem in refrigerated environments where food is processed. in an exercise aimed to study the potential of nitric oxide donors as biofilm dispersal in refrigerated conditions, we compare ...201627457245
from discovery to production: biotechnology of marine fungi for the production of new antibiotics.filamentous fungi are well known for their capability of producing antibiotic natural products. recent studies have demonstrated the potential of antimicrobials with vast chemodiversity from marine fungi. development of such natural products into lead compounds requires sustainable supply. marine biotechnology can significantly contribute to the production of new antibiotics at various levels of the process chain including discovery, production, downstream processing, and lead development. howev ...201627455283
molecular mapping of high resistance to bacterial leaf spot in lettuce pi 358001-1.lettuce (lactuca sativa l.) is a diploid (2n = 18) with a genome size of 2,600 mbp, and belongs to the family compositae. bacterial leaf spot (bls), caused by xanthomonas campestris pv. vitians, is a major disease of lettuce worldwide. leaf lettuce pi 358001-1 has been characterized as an accession highly resistant to bls and has white seed. in order to understand inheritance of the high resistance in this germplasm line, an f3 population consisting of 163 families was developed from the cross p ...201627454703
coronatine facilitates pseudomonas syringae infection of arabidopsis leaves at night.in many land plants, the stomatal pore opens during the day and closes during the night. thus, periods of darkness could be effective in decreasing pathogen penetration into leaves through stomata, the primary sites for infection by many pathogens. pseudomonas syringae pv. tomato (pst) dc3000 produces coronatine (cor) and opens stomata, raising an intriguing question as to whether this is a virulence strategy to facilitate bacterial infection at night. in fact, we found that (a) biological conce ...201627446113
the complete sequences and ecological roles of two incp-1β plasmids, phb44 and pbs64, isolated from the mycosphere of laccaria proxima.two novel plasmids, coined phb44 and pbs64, were recently found in variovorax paradoxus strains hb44 and bs64 isolated from the mycosphere of laccaria proxima, on two different sampling occasions. we here describe the full sequences of phb44 and pbs64 and establish their evolutionary placement and ecological function. both plasmids, unique for mycospheric v. paradoxus, were around 58 kb in size. they possessed, in a very similar fashion, three main plasmid backbone regions, which were predicted ...201627445994
biophysical and biochemical studies of a major endoglucanase secreted by xanthomonas campestris pv. campestris.endoglucanases are the main cellulolytic enzymes secreted by the bacterium xanthomonas campestris pv. campestris (xcc). the major endoglucanase exported by this bacterium into an external milieu is an enzyme xcccel5a, which belongs to gh5 family subfamily 1 and is encoded by the gene engxca. we purified xcccel5a using ammonium sulfate precipitation followed by size exclusion chromatography and identified it by zymogram analysis. circular dichroism and fluorescence spectroscopy studies showed tha ...201627444323
quantitative, image-based phenotyping methods provide insight into spatial and temporal dimensions of plant disease.plant disease symptoms exhibit complex spatial and temporal patterns that are challenging to quantify. image-based phenotyping approaches enable multidimensional characterization of host-microbe interactions and are well suited to capture spatial and temporal data that are key to understanding disease progression. we applied image-based methods to investigate cassava bacterial blight, which is caused by the pathogen xanthomonas axonopodis pv. manihotis (xam). we generated xam strains in which in ...201627443602
responses to combined abiotic and biotic stress in tomato are governed by stress intensity and resistance mechanism.stress conditions in agricultural ecosystems can occur at variable intensities. different resistance mechanisms against abiotic stress and pathogens are deployed by plants. thus, it is important to examine plant responses to stress combinations under different scenarios. here, we evaluated the effect of different levels of salt stress ranging from mild to severe (50, 100, and 150mm nacl) on powdery mildew resistance and overall performance of tomato introgression lines with contrasting levels of ...201627436279
promiscuous diffusible signal factor production and responsiveness of the xylella fastidiosa rpf system.cell density-dependent regulation of gene expression in xylella fastidiosa that is crucial to its switching between plant hosts and insect vectors is dependent on rpff and its production of 2-enoic acids known as diffusible signal factor (dsf). we show that x. fastidiosa produces a particularly large variety of similar, relatively long-chain-length 2-enoic acids that are active in modulating gene expression. both x. fastidiosa itself and a pantoea agglomerans surrogate host harboring x. fastidio ...201627435463
the molecular basis for ubiquitin and ubiquitin-like specificities in bacterial effector proteases.pathogenic bacteria rely on secreted effector proteins to manipulate host signaling pathways, often in creative ways. ce clan proteases, specific hydrolases for ubiquitin-like modifications (sumo and nedd8) in eukaryotes, reportedly serve as bacterial effector proteins with desumoylase, deubiquitinase, or, even, acetyltransferase activities. here, we characterize bacterial ce protease activities, revealing k63-linkage-specific deubiquitinases in human pathogens, such as salmonella, escherichia, ...201627425412
the xanthomonas campestris pv. vesicatoria type-3 effector xopb inhibits plant defence responses by interfering with ros production.the bacterial pathogen xanthomonas campestris pv. vesicatoria 85-10 (xcv) translocates about 30 type-3 effector proteins (t3es) into pepper plants (capsicum annuum) to suppress plant immune responses. among them is xopb which interferes with pti, eti and sugar-mediated defence responses, but the underlying molecular mechanisms and direct targets are unknown so far. here, we examined the xopb-mediated suppression of plant defence responses in more detail. infection of susceptible pepper plants wi ...201627398933
cloning-free genome engineering in sinorhizobium meliloti advances applications of cre/loxp site-specific recombination.the soil-dwelling α-proteobacterium sinorhizobium meliloti serves as model for studies of symbiotic nitrogen fixation, a highly important process in sustainable agriculture. here, we report advancements of the genetic toolbox accelerating genome editing in s. meliloti. the hsdmsr operon encodes a type-i restriction-modification (r-m) system. transformation of s. meliloti is counteracted by the restriction endonuclease hsdr degrading dna which lacks the appropriate methylation pattern. we provide ...201627393468
dcsbis (pa2771) from pseudomonas aeruginosa is a highly active diguanylate cyclase with unique activity regulation.c-di-gmp (3',5' -cyclic diguanylic acid) is an important second messenger in bacteria that influences virulence, motility, biofilm formation, and cell division. the level of c-di-gmp in cells is controlled by diguanyl cyclases (dgcs) and phosphodiesterases (pdes). here, we report the biochemical functions and crystal structure of the potential diguanylase dcsbis (pa2771, a diguanylate cyclase with a self-blocked i-site) from pseudomonas aeruginosa pao1. the full-length dcsbis protein contains an ...201627388857
next-generation sequencing diagnostics of bacteremia in septic patients.bloodstream infections remain one of the major challenges in intensive care units, leading to sepsis or even septic shock in many cases. due to the lack of timely diagnostic approaches with sufficient sensitivity, mortality rates of sepsis are still unacceptably high. however a prompt diagnosis of the causative microorganism is critical to significantly improve outcome of bloodstream infections. although various targeted molecular tests for blood samples are available, time-consuming blood cultu ...201627368373
multilocus sequence typing of strains of bacterial spot of lettuce collected in the united states.studies on genetic diversity and recombination in bacterial pathogens are providing a better understanding of the mechanisms shaping bacterial diversity, which can affect disease control. xanthomonas campestris pv. vitians, causal agent of bacterial leaf spot of lettuce, is a threat to the worldwide lettuce industry. we examined the genetic variation within a sample of 83 strains from california, florida, and ohio using multilocus sequence typing of six housekeeping genes, totaling 2.7 kb. addit ...201627359264
discovery and identification of candidate genes from the chitinase gene family for verticillium dahliae resistance in cotton.verticillium dahliae, a destructive and soil-borne fungal pathogen, causes massive losses in cotton yields. however, the resistance mechanism to v. dahilae in cotton is still poorly understood. accumulating evidence indicates that chitinases are crucial hydrolytic enzymes, which attack fungal pathogens by catalyzing the fungal cell wall degradation. as a large gene family, to date, the chitinase genes (chis) have not been systematically analyzed and effectively utilized in cotton. here, we ident ...201627354165
xanthoferrin, the α-hydroxycarboxylate-type siderophore of xanthomonas campestris pv. campestris, is required for optimum virulence and growth inside cabbage.xanthomonas campestris pv. campestris causes black rot, a serious disease of crucifers. xanthomonads encode a siderophore biosynthesis and uptake gene cluster xss (xanthomonas siderophore synthesis) involved in the production of a vibrioferrin-type siderophore. however, little is known about the role of the siderophore in the iron uptake and virulence of x. campestris pv. campestris. in this study, we show that x. campestris pv. campestris produces an α-hydroxycarboxylate-type siderophore (named ...201627348422
elucidation of a masked repeating structure of the o-specific polysaccharide of the halotolerant soil bacteria azospirillum halopraeferens au4.an o-specific polysaccharide was obtained by mild acid hydrolysis of the lipopolysaccharide isolated by the phenol-water extraction from the halotolerant soil bacteria azospirillum halopraeferens type strain au4. the polysaccharide was studied by sugar and methylation analyses, selective cleavages by smith degradation and solvolysis with trifluoroacetic acid, one- and two-dimensional (1)h and (13)c nmr spectroscopy. the following masked repeating structure of the o-specific polysaccharide was es ...201627340454
biosynthesis of α-pyrones.the α-pyrone moiety is a structural feature found in a huge variety of biologically active metabolites. in recent times new insights into additional biosynthetic mechanisms, yielding in such six-membered unsaturated ester ring residues have been obtained. the purpose of this mini-review is to give a brief overview of α-pyrones and the mechanisms forming the basis of their natural synthesis. especially the chain interconnecting enzymes, showing homology to ketosynthases which catalyze claisen-lik ...201627340449
mechanism and function of type iv secretion during infection of the human host.bacterial pathogens employ type iv secretion systems (t4sss) for various purposes to aid in survival and proliferation in eukaryotic hosts. one large t4ss subfamily, the conjugation systems, confers a selective advantage to the invading pathogen in clinical settings through dissemination of antibiotic resistance genes and virulence traits. besides their intrinsic importance as principle contributors to the emergence of multiply drug-resistant "superbugs," detailed studies of these highly tractab ...201627337453
function of succinoglycan polysaccharide in sinorhizobium meliloti host plant invasion depends on succinylation, not molecular weight.the acidic polysaccharide succinoglycan produced by the rhizobial symbiont sinorhizobium meliloti 1021 is required for this bacterium to invade the host plant medicago truncatula and establish a nitrogen-fixing symbiosis. s. meliloti mutants that cannot make succinoglycan cannot initiate invasion structures called infection threads in plant root hairs. s. meliloti exoh mutants that cannot succinylate succinoglycan are also unable to form infection threads, despite the fact that they make large q ...201627329751
screening, isolation, and identification of food-originated compounds enhancing the ice-nucleation activity of xanthomonas campestris.some foods from plant sources, particularly of moringeceae origin, contained compounds that enhanced bacterial ice-nucleation activity. a hot water extract from mustard seeds was so potent in its enhancing activity that the compounds responsible could be isolated from the seeds as yellow crystals. by instrumental analyses, this enhancer was identified as 4-hydroxy-3-nitrophenylacetic acid. the addition of a purified preparation of this compound at 0.1-1 ppm to the cultivation medium for xanthomo ...199427315706
bacterial cell biology outside the streetlight.as much as vertical transmission of microbial symbionts requires their deep integration into the host reproductive and developmental biology, symbiotic lifestyle might profoundly affect bacterial growth and proliferation. this review describes the reproductive oddities displayed by bacteria associated - more or less intimately - with multicellular eukaryotes.201627306428
detection of novel integrons in the metagenome of human saliva.integrons are genetic elements capable of capturing and expressing open reading frames (orfs) embedded within gene cassettes. they are involved in the dissemination of antibiotic resistance genes (args) in clinically important pathogens. although the args are common in the oral cavity the association of integrons and antibiotic resistance has not been reported there. in this work, a pcr-based approach was used to investigate the presence of integrons and associated gene cassettes in human oral m ...201627304457
pf filamentous phage requires uvrd for replication in pseudomonas aeruginosa.pf is a lysogenic filamentous phage that promotes biofilm development in pseudomonas aeruginosa. pf replicates by a rolling circle replication system which depends on a phage-encoded initiator protein and host factors usually involved in chromosome replication. rep, an accessory replicative dna helicase, is crucial for replication of filamentous phages in escherichia coli. in contrast, here we show that, instead of depending on rep, pf replication depends on uvrd, an accessory helicase implicate ...201627303696
multiple targets of salicylic acid and its derivatives in plants and animals.salicylic acid (sa) is a critical plant hormone that is involved in many processes, including seed germination, root initiation, stomatal closure, floral induction, thermogenesis, and response to abiotic and biotic stresses. its central role in plant immunity, although extensively studied, is still only partially understood. classical biochemical approaches and, more recently, genome-wide high-throughput screens have identified more than two dozen plant sa-binding proteins (sabps), as well as mu ...201627303403
changes in the aggressiveness and fecundity of hot pepper anthracnose pathogen (colletotricum acutatum) under elevated co2 and temperature over 100 infection cycles.we observed the changes in aggressiveness and fecundity of the anthracnose pathogen colletotrichum acutatum on hot pepper, under the ambient and the twice-ambient treatments. artificial infection was repeated over 100 cycles for ambient (25°c/400 ppm co2) and twice-ambient (30°c/700 ppm co2) growth chamber conditions, over 3 years. during repeated infection cycles (ics) on green-pepper fruits, the aggressiveness (incidence [% of diseased fruits among 20 inoculated fruits] and severity [lesion le ...201627298601
dna microarray and gene ontology enrichment analysis reveals that a mutation in opsx affects virulence and chemotaxis in xanthomonas oryzae pv. oryzae.xanthomonas oryzae pv. oryzae (xoo) causes bacterial leaf blight (blb) in rice (oryza sativa l.). in this study, we investigated the effect of a mutation in opsx (xoo1056), which encodes a saccharide biosynthesis regulatory protein, on the virulence and bacterial chemotaxis of xoo. we performed dna microarray analysis, which showed that 63 of 2,678 genes, including genes related to bacterial motility (flagellar and chemotaxis proteins) were significantly downregulated (<-2 log2 fold changes) by ...201627298594
morphological and physiological changes induced by contact-dependent interaction between candida albicans and fusobacterium nucleatum.candida albicans and fusobacterium nucleatum are well-studied oral commensal microbes with pathogenic potential that are involved in various oral polymicrobial infectious diseases. recently, we demonstrated that f. nucleatum atcc 23726 coaggregates with c. albicans sn152, a process mainly mediated by fusobacterial membrane protein radd and candida cell wall protein flo9. the aim of this study was to investigate the potential biological impact of this inter-kingdom interaction. we found that f. n ...201627295972
two isocitrate dehydrogenases from a plant pathogen xanthomonas campestris pv. campestris 8004. bioinformatic analysis, enzymatic characterization, and implication in virulence.isocitrate dehydrogenase (idh) is a key enzyme in the tricarboxylate (tca) cycle, which may play an important role in the virulence of pathogenic bacteria. here, two structurally different idhs from a plant pathogen xanthomonas campestris pv. campestris 8004 (xccidh1 and xccidh2) were characterized in detail. the recombinant xccidh1 forms homodimer in solution, while the recombinant xccidh2 is a typical monomer. phylogenetic analysis showed that xccidh1 belongs to the type i idh subfamily and xc ...201627282849
immune sensing of lipopolysaccharide in plants and animals: same but different. 201627281177
high-pressure sterilization of ice nucleation-active xanthomonas campestris and its application to egg processing.xanthomonas campestris inxc-1 is able to freeze water at a subzero temperature higher than -5°c. high-pressure treatment at 300 mpa and 5°c for 5 min killed the cells without affecting their ice-nucleation activity. egg white containing the pressurized cells began to freeze with a slight degree of supercooling. ice crystals with a dendritic structure were formed when the egg white froze in the presence of the killed bacterial cells. the frozen egg white thawed more quickly than egg white frozen ...199327280991
enzymatic synthesis of bioactive compounds with high potential for cosmeceutical application.cosmeceuticals are cosmetic products containing biologically active ingredients purporting to offer a pharmaceutical therapeutic benefit. the active ingredients can be extracted and purified from natural sources (botanicals, herbal extracts, or animals) but can also be obtained biotechnologically by fermentation and cell cultures or by enzymatic synthesis and modification of natural compounds. a cosmeceutical ingredient should possess an attractive property such as anti-oxidant, anti-inflammator ...201627276911
pseudomonas syringae type iii effector hopaf1 suppresses plant immunity by targeting methionine recycling to block ethylene induction.hopaf1 is a type iii effector protein of unknown function encoded in the genomes of several strains of pseudomonas syringae and other plant pathogens. structural modeling predicted that hopaf1 is closely related to deamidase proteins. deamidation is the irreversible substitution of an amide group with a carboxylate group. several bacterial virulence factors are deamidases that manipulate the activity of specific host protein substrates. we identified arabidopsis methylthioadenosine nucleosidase ...201627274076
directed evolution of fls2 towards novel flagellin peptide recognition.microbe-associated molecular patterns (mamps) are molecules, or domains within molecules, that are conserved across microbial taxa and can be recognized by a plant or animal immune system. although mamp receptors have evolved to recognize conserved epitopes, the mamps in some microbial species or strains have diverged sufficiently to render them unrecognizable by some host immune systems. in this study, we carried out in vitro evolution of the arabidopsis thaliana flagellin receptor flagellin-se ...201627270917
an innate immunity pathway in the moss physcomitrella patens.map kinase (mpk) cascades in arabidopsis thaliana and other vascular plants are activated by developmental cues, abiotic stress, and pathogen infection. much less is known of mpk functions in nonvascular land plants such as the moss physcomitrella patens here, we provide evidence for a signaling pathway in p. patens required for immunity triggered by pathogen associated molecular patterns (pamps). this pathway induces rapid growth inhibition, a novel fluorescence burst, cell wall depositions, an ...201627268428
identification of the c-terminal gh5 domain from cbcel9b/man5a as the first glycoside hydrolase with thermal activation property from a multimodular bifunctional enzyme.caldicellulosiruptor bescii encodes at least six unique multimodular glycoside hydrolases crucial for plant cell wall polysaccharides degradation, with each having two catalytic domains separated by two to three carbohydrate binding modules. among the six enzymes, three have one n- or c-terminal gh5 domain with identical amino acid sequences. despite a few reports on some of these multimodular enzymes, little is known about how the conserved gh5 domains behave, which are believed to be important ...201627258548
multiple patterns of regulation and overexpression of a ribonuclease-like pathogenesis-related protein gene, ospr10a, conferring disease resistance in rice and arabidopsis.an abundant 17 kda rnase, encoded by ospr10a (also known as pbz1), was purified from pi-starved rice suspension-cultured cells. biochemical analysis showed that the range of optimal temperature for its rnase activity was 40-70°c and the optimum ph was 5.0. disulfide bond formation and divalent metal ion mg2+ were required for the rnase activity. the expression of ospr10a::gus in transgenic rice was induced upon phosphate (pi) starvation, wounding, infection by the pathogen xanthomonas oryzae pv. ...201627258121
complete genome sequences of lytic bacteriophages of xanthomonas arboricola pv. juglandis.three bacteriophages, f20-xaj, f29-xaj, and f30-xaj, with lytic activity against xanthomonas arboricola pv. juglandis were isolated from walnut trees (viii bío bío region, chile). these lytic bacteriophages have double-stranded dna (dsdna) genomes of 43,851 bp, 41,865 bp, and 44,262 bp, respectively. these are the first described bacteriophages with lytic activity against x. arboricola pv. juglandis that can be utilized as biocontrol agents.201627257210
emerging insights on brazilian pepper tree (schinus terebinthifolius) invasion: the potential role of soil microorganisms.invasive plant species constitute a major ecological and economic problem worldwide, often distorting trophic levels and ecosystem balance. numerous studies implicate factors ranging from environmental plasticity, competition for nutrient and space, and allelopathy in the success of invasive species in general. the brazilian pepper tree (bp) was introduced to the united states in the 1800s and has since become a category one invasive plant in florida. it has aggressively spread to about 3000 km( ...201627252726
aba suppresses botrytis cinerea elicited no production in tomato to influence h2o2 generation and increase host susceptibility.abscisic acid (aba) production has emerged a susceptibility factor in plant-pathogen interactions. this work examined the interaction of aba with nitric oxide (no) in tomato following challenge with the aba-synthesizing pathogen, botrytis cinerea. trace gas detection using a quantum cascade laser detected no production within minutes of challenge with b. cinerea whilst photoacoustic laser detection detected ethylene production - an established mediator of defense against this pathogen - occurrin ...201627252724
presence of extracellular dna during biofilm formation by xanthomonas citri subsp. citri strains with different host range.xanthomonas citri subsp. citri (xcc) a strain causes citrus bacterial canker, a serious leaf, fruit and stem spotting disease of several citrus species. x. alfalfae subsp. citrumelonis (xac) is the cause of citrus bacterial spot, a minor disease of citrus nursery plants and x. campestris pv. campestris (xc) is a systemic pathogen that causes black rot of cabbage. xanthomonas spp. form biofilms in planta that facilitate the host infection process. herein, the role of extracellular dna (edna) was ...201627248687
a phytophthora sojae effector pscrn63 forms homo-/hetero-dimers to suppress plant immunity via an inverted association manner.oomycete pathogens produce a large number of effectors to promote infection. their mode of action are largely unknown. here we show that a phytophthora sojae effector, pscrn63, suppresses flg22-induced expression of frk1 gene, a molecular marker in pathogen-associated molecular patterns (pamp)-triggered immunity (pti). however, pscrn63 does not suppress upstream signaling events including flg22-induced mapk activation and bik1 phosphorylation, indicating that it acts downstream of mapk cascades. ...201627243217
plant genetic background increasing the efficiency and durability of major resistance genes to root-knot nematodes can be resolved into a few resistance qtls.with the banning of most chemical nematicides, the control of root-knot nematodes (rkns) in vegetable crops is now based essentially on the deployment of single, major resistance genes (r-genes). however, these genes are rare and their efficacy is threatened by the capacity of rkns to adapt. in pepper, several dominant r-genes are effective against rkns, and their efficacy and durability have been shown to be greater in a partially resistant genetic background. however, the genetic determinants ...201627242835
type ii toxin-antitoxin distribution and adaptive aspects on xanthomonas genomes: focus on xanthomonas citri.prokaryotic toxin-antitoxin (ta) systems were first described as being designed to prevent plasmid loss in bacteria. however, with the increase in prokaryotic genome sequencing, recently many tas have been found in bacterial chromosomes, having other biological functions, such as environmental stress response. to date, only few studies have focused on ta systems in phytopathogens, and their possible impact on the bacterial fitness. this may be especially important for pathogens like xanthomonas ...201627242687
the type iii effector avrxccb in xanthomonas campestris pv. campestris targets putative methyltransferases and suppresses innate immunity in arabidopsis.xanthomonas campestris pv. campestris (xcc) causes black rot, one of the most important diseases of brassica crops worldwide. the type iii effector inventory plays important roles in the virulence and pathogenicity of the pathogen. however, little is known about the virulence function(s) of the putative type iii effector avrxccb in xcc. here, we investigated the immune suppression ability of avrxccb and the possible underlying mechanisms. avrxccb was demonstrated to be secreted in a type iii sec ...201627241588
cloning and expression analysis of cinnamoyl-coa reductase (ccr) genes in sorghum.cinnamoyl-coa reductase (ccr) is the first enzyme in the monolignol-specific branch of the lignin biosynthetic pathway. in this research, three sorghum ccr genes including sbccr1, sbccr2-1 and sbccr2-2 were cloned and characterized. analyses of the structure and phylogeny of the three ccr genes showed evolutionary conservation of the functional domains and divergence of function. transient expression assays in nicotiana benthamiana leaves demonstrated that the three ccr proteins were localized i ...201627231650
loss of gltb inhibits biofilm formation and biocontrol efficiency of bacillus subtilis bs916 by altering the production of γ-polyglutamate and three lipopeptides.this study examined the contribution of gltb on biofilm formation and biocontrol efficiency of b. subtilis bs916.201627223617
the influence of a modified lipopolysaccharide o-antigen on the biosynthesis of xanthan in xanthomonas campestris pv. campestris b100.the exopolysaccharide xanthan is a natural product which is extensively used in industry. it is a thickening agent in many fields, from oil recovery to the food sector. xanthan is produced by the gram negative bacterium xanthomonas campestris pv. campestris (xcc). we analyzed the lipopolysaccharide (lps) of three mutant strains of the xcc wild type b100 to distinguish if the xanthan production can be increased when lps biosynthesis is affected.201627215401
a minimal threshold of c-di-gmp is essential for fruiting body formation and sporulation in myxococcus xanthus.generally, the second messenger bis-(3'-5')-cyclic dimeric gmp (c-di-gmp) regulates the switch between motile and sessile lifestyles in bacteria. here, we show that c-di-gmp is an essential regulator of multicellular development in the social bacterium myxococcus xanthus. in response to starvation, m. xanthus initiates a developmental program that culminates in formation of spore-filled fruiting bodies. we show that c-di-gmp accumulates at elevated levels during development and that this increas ...201627214040
bacterial molecular signals in the sinorhizobium fredii-soybean symbiosis.sinorhizobium (ensifer) fredii (s. fredii) is a rhizobial species exhibiting a remarkably broad nodulation host-range. thus, s. fredii is able to effectively nodulate dozens of different legumes, including plants forming determinate nodules, such as the important crops soybean and cowpea, and plants forming indeterminate nodules, such as glycyrrhiza uralensis and pigeon-pea. this capacity of adaptation to different symbioses makes the study of the molecular signals produced by s. fredii strains ...201627213334
hrcu and hrpp are pathogenicity factors in the fire blight pathogen erwinia amylovora required for the type iii secretion of dspa/e.many gram-negative bacterial pathogens mediate host-microbe interactions via utilization of the type iii secretion (t3s) system. the t3s system is a complex molecular machine consisting of more than 20 proteins. collectively, these proteins translocate effectors across extracellular space and into the host cytoplasm. successful translocation requires timely synthesis and allocation of both structural and secreted t3s proteins. based on amino acid conservation in animal pathogenic bacteria, hrcu ...201627206522
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