Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| proteomics of effector-triggered immunity (eti) in plants. | effector-triggered immunity (eti) was originally termed gene-for-gene resistance and dates back to fundamental observations of flax resistance to rust fungi by harold henry flor in the 1940s. since then, genetic and biochemical approaches have defined our current understanding of how plant "resistance" proteins recognize microbial effectors. more recently, proteomic approaches have expanded our view of the protein landscape during eti and contributed significant advances to our mechanistic under ... | 2014 | 25513776 |
| plant immunity in plant-aphid interactions. | aphids are economically important pests that cause extensive feeding damage and transmit viruses. while some species have a broad host range and cause damage to a variety of crops, others are restricted to only closely related plant species. while probing and feeding aphids secrete saliva, containing effectors, into their hosts to manipulate host cell processes and promote infestation. aphid effector discovery studies pointed out parallels between infection and infestation strategies of plant pa ... | 2014 | 25520727 |
| improving crop disease resistance: lessons from research on arabidopsis and tomato. | one of the great challenges for food security in the 21st century is to improve yield stability through the development of disease-resistant crops. crop research is often hindered by the lack of molecular tools, growth logistics, generation time and detailed genetic annotations, hence the power of model plant species. our knowledge of plant immunity today has been largely shaped by the use of models, specifically through the use of mutants. we examine the importance of arabidopsis and tomato as ... | 2014 | 25520730 |
| loss of arabidopsis thaliana dynamin-related protein 2b reveals separation of innate immune signaling pathways. | vesicular trafficking has emerged as an important means by which eukaryotes modulate responses to microbial pathogens, likely by contributing to the correct localization and levels of host components necessary for effective immunity. however, considering the complexity of membrane trafficking in plants, relatively few vesicular trafficking components with functions in plant immunity are known. here we demonstrate that arabidopsis thaliana dynamin-related protein 2b (drp2b), which has been previo ... | 2014 | 25521759 |
| microbe-associated molecular pattern-induced calcium signaling requires the receptor-like cytoplasmic kinases, pbl1 and bik1. | plant perception of conserved microbe-derived or damage-derived molecules (so-called microbe- or damage-associated molecular patterns, mamps or damps, respectively) triggers cellular signaling cascades to initiate counteracting defence responses. using mamp-induced rise in cellular calcium levels as one of the earliest biochemical readouts, we initiated a genetic screen for components involved in early mamp signaling in arabidopsis thaliana. | 2014 | 25522736 |
| the escherichia coli effector espj blocks src kinase activity via amidation and adp ribosylation. | the hallmark of enteropathogenic escherichia coli (epec) infection is the formation of actin-rich pedestal-like structures, which are generated following phosphorylation of the bacterial effector tir by cellular src and abl family tyrosine kinases. this leads to recruitment of the nck-wip-n-wasp complex that triggers arp2/3-dependent actin polymerization in the host cell. the same phosphorylation-mediated signalling network is also assembled downstream of the vaccinia virus protein a36 and the p ... | 2014 | 25523213 |
| salicylic acid signal transduction: the initiation of biosynthesis, perception and transcriptional reprogramming. | the phytohormone salicylic acid (sa) is a small phenolic compound that regulates diverse physiological processes, in particular plant resistance against pathogens. understanding sa-mediated signaling has been a major focus of plant research. pathogen-induced sa is mainly synthesized via the isochorismate pathway in chloroplasts, with ics1 (isochorismate synthase 1) being a critical enzyme. calcium signaling regulates activities of a subset of transcription factors thereby activating nuclear ics1 ... | 2014 | 25538725 |
| a new recombineering system for photorhabdus and xenorhabdus. | precise and fluent genetic manipulation is still limited to only a few prokaryotes. ideally the highly advanced technologies available in escherichia coli could be broadly applied. our efforts to apply lambda red technology, widely termed 'recombineering', in photorhabdus and xenorhabdus yielded only limited success. consequently we explored the properties of an endogenous photorhabdus luminescens lambda red-like operon, plu2934/plu2935/plu2936. bioinformatic and functional tests indicate that p ... | 2014 | 25539914 |
| a new recombineering system for photorhabdus and xenorhabdus. | precise and fluent genetic manipulation is still limited to only a few prokaryotes. ideally the highly advanced technologies available in escherichia coli could be broadly applied. our efforts to apply lambda red technology, widely termed 'recombineering', in photorhabdus and xenorhabdus yielded only limited success. consequently we explored the properties of an endogenous photorhabdus luminescens lambda red-like operon, plu2934/plu2935/plu2936. bioinformatic and functional tests indicate that p ... | 2014 | 25539914 |
| polyphenol oxidase as a biochemical seed defense mechanism. | seed dormancy and resistance to decay are fundamental survival strategies, which allow a population of seeds to germinate over long periods of time. seeds have physical, chemical, and biological defense mechanisms that protect their food reserves from decay-inducing organisms and herbivores. here, we hypothesize that seeds also possess enzyme-based biochemical defenses, based on induction of the plant defense enzyme, polyphenol oxidase (ppo), when wild oat (avena fatua l.) caryopses and seeds we ... | 2014 | 25540647 |
| production of novel antibiotics zeamines through optimizing dickeya zeae fermentation conditions. | dickeya zeae strain ec1 was recently shown to produce a new type of phytotoxins designated as zeamine and zeamine ii, which are potent wide-spectrum antibiotics against gram-positive and gram-negative bacterial pathogens, suggesting their promising potential as clinical medicines. in this study, the optimized medium composition and culture conditions for biosynthesis of novel antibiotics zeamines have been established by using response surface methodology, largely increasing the yield of zeamine ... | 2014 | 25541733 |
| characterization of the algc gene expression pattern in the multidrug resistant acinetobacter baumannii aiims 7 and correlation with biofilm development on abiotic surface. | relative quantification of algc gene expression was evaluated in the multidrug resistant strain acinetobacter baumannii aiims 7 biofilm (3 to 96 h, on polystyrene surface) compared to the planktonic counterparts. comparison revealed differential algc expression pattern with maximum 81.59-fold increase in biofilm cells versus 3.24-fold in planktonic cells (p < 0.05). expression levels strongly correlated with specific biofilm stages (scale of 3 to 96 h), coinciding maximum at initial surface atta ... | 2014 | 25544957 |
| immunomodulation by the pseudomonas syringae hopz type iii effector family in arabidopsis. | pseudomonas syringae employs a type iii secretion system to inject 20-30 different type iii effector (t3se) proteins into plant host cells. a major role of t3ses is to suppress plant immune responses and promote bacterial infection. the yopj/hopz acetyltransferases are a superfamily of t3ses found in both plant and animal pathogenic bacteria. in p. syringae, this superfamily includes the evolutionarily diverse hopz1, hopz2 and hopz3 alleles. to investigate the roles of the hopz family in immunom ... | 2014 | 25546415 |
| atrop1 negatively regulates potato resistance to phytophthora infestans via nadph oxidase-mediated accumulation of h2o2. | small gtpases are monomeric guanine nucleotide-binding proteins. in plants, rops regulate plant cell polarity, plant cell differentiation and development as well as biotic and abiotic stress signaling pathways. | 2014 | 25547733 |
| a vector system for abc transporter-mediated secretion and purification of recombinant proteins in pseudomonas species. | pseudomonas fluorescens is an efficient platform for recombinant protein production. p. fluorescens has an abc transporter secreting endogenous thermostable lipase (tlia) and protease, which can be exploited to transport recombinant proteins across the cell membrane. in this study, the expression vector pdart was constructed by inserting tlidef, genes encoding the abc transporter, along with the construct of the lipase abc transporter recognition domain (lard), into pdsk519, a widely used shuttl ... | 2015 | 25548043 |
| aspergiloid i, an unprecedented spirolactone norditerpenoid from the plant-derived endophytic fungus aspergillus sp. yxf3. | an unusual c18 norditerpenoid, aspergiloid i (1), was isolated from the culture broth of aspergillus sp. yxf3, an endophytic fungus derived from ginkgo biloba. its structure was unambiguously established by analysis of hrms-esi and spectroscopic data, and the absolute configuration was determined by low-temperature (100 k) single crystal x-ray diffraction with cu kα radiation. this compound is structurally characterized by a new carbon skeleton with an unprecedented 6/5/6 tricyclic ring system b ... | 2014 | 25550731 |
| plant pathogenic bacteria target the actin microfilament network involved in the trafficking of disease defense components. | cells of infected organisms transport disease defense-related molecules along actin filaments to deliver them to their sites of action to combat the pathogen. to accommodate higher demand for intracellular traffic, plant f-actin density increases transiently during infection or treatment of arabidopsis with pathogen-associated molecules. many animal and plant pathogens interfere with actin polymerization and depolymerization to avoid immune responses. pseudomonas syringae, a plant extracellular ... | 2014 | 25551177 |
| co-localisation of the blackleg resistance genes rlm2 and lepr3 on brassica napus chromosome a10. | the protection of canola (brassica napus) crops against blackleg disease, caused by the fungal pathogen leptosphaeria maculans, is largely mediated by race-specific resistance genes (r-genes). while many r-genes effective against blackleg disease have been identified in brassica species, information of the precise genomic locations of the genes is limited. | 2014 | 25551287 |
| molecular variation and horizontal gene transfer of the homocysteine methyltransferase gene mmum and its distribution in clinical pathogens. | the homocysteine methyltransferase encoded by mmum is widely distributed among microbial organisms. it is the key enzyme that catalyzes the last step in methionine biosynthesis and plays an important role in the metabolism process. it also enables the microbial organisms to tolerate high concentrations of selenium in the environment. in this research, 533 mmum gene sequences covering 70 genera of the bacteria were selected from genbank database. the distribution frequency of mmum is different in ... | 2015 | 25552925 |
| hypersensitive response-like lesions 1 codes for atppt1 and regulates accumulation of ros and defense against bacterial pathogen pseudomonas syringae in arabidopsis thaliana. | plants employ both basal and resistance gene (r gene)-mediated defenses in response to pathogens. reactive oxygen species (ros) are widely reported to play a central role in both basal and r gene-mediated defense; however, the nature of ros has been less well established for basal defense. in addition, spatial distribution of redox moieties and mechanisms of plant responses during basal defense are poorly understood. we investigated redox signaling in arabidopsis thaliana in response to virulent ... | 2015 | 25557512 |
| the cre1 cytokinin pathway is differentially recruited depending on medicago truncatula root environments and negatively regulates resistance to a pathogen. | cytokinins are phytohormones that regulate many developmental and environmental responses. the medicago truncatula cytokinin receptor mtcre1 (cytokinin response 1) is required for the nitrogen-fixing symbiosis with rhizobia. as several cytokinin signaling genes are modulated in roots depending on different biotic and abiotic conditions, we assessed potential involvement of this pathway in various root environmental responses. phenotyping of cre1 mutant roots infected by the gigaspora margarita a ... | 2015 | 25562779 |
| yeast cell wall extract induces disease resistance against bacterial and fungal pathogens in arabidopsis thaliana and brassica crop. | housaku monogatari (hm) is a plant activator prepared from a yeast cell wall extract. we examined the efficacy of hm application and observed that hm treatment increased the resistance of arabidopsis thaliana and brassica rapa leaves to bacterial and fungal infections. hm reduced the severity of bacterial leaf spot and anthracnose on a. thaliana and brassica crop leaves with protective effects. in addition, gene expression analysis of a. thaliana plants after treatment with hm indicated increase ... | 2015 | 25565273 |
| structural insight into effector proteins of gram-negative bacterial pathogens that modulate the phosphoproteome of their host. | invading pathogens manipulate cellular process of the host cell to establish a safe replicative niche. to this end they secrete a spectrum of proteins called effectors that modify cellular environment through a variety of mechanisms. one of the most important mechanisms is the manipulation of cellular signaling through modifications of the cellular phosphoproteome. phosphorylation/dephosphorylation plays a pivotal role in eukaryotic cell signaling, with ∼ 500 different kinases and ∼ 130 phosphat ... | 2015 | 25565677 |
| microbial interactions and the ecology and evolution of hawaiian drosophilidae. | adaptive radiations are characterized by an increased rate of speciation and expanded range of habitats and ecological niches exploited by those species. the hawaiian drosophilidae is a classic adaptive radiation; a single ancestral species colonized hawaii approximately 25 million years ago and gave rise to two monophyletic lineages, the hawaiian drosophila and the genus scaptomyza. the hawaiian drosophila are largely saprophagous and rely on approximately 40 endemic plant families and their as ... | 2014 | 25566196 |
| virus ecology and disturbances: impact of environmental disruption on the viruses of microorganisms. | 2014 | 25566216 | |
| vibrio parahaemolyticus: a review on the pathogenesis, prevalence, and advance molecular identification techniques. | vibrio parahaemolyticus is a gram-negative halophilic bacterium that is found in estuarine, marine and coastal environments. v. parahaemolyticus is the leading causal agent of human acute gastroenteritis following the consumption of raw, undercooked, or mishandled marine products. in rare cases, v. parahaemolyticus causes wound infection, ear infection or septicaemia in individuals with pre-existing medical conditions. v. parahaemolyticus has two hemolysins virulence factors that are thermostabl ... | 2014 | 25566219 |
| nonhost resistance to rust pathogens - a continuation of continua. | the rust fungi (order: pucciniales) are a group of widely distributed fungal plant pathogens, which can infect representatives of all vascular plant groups. rust diseases significantly impact several crop species and considerable research focuses on understanding the basis of host specificity and nonhost resistance. like many pathogens, rust fungi vary considerably in the number of hosts they can infect, such as wheat leaf rust (puccinia triticina), which can only infect species in the genera tr ... | 2014 | 25566270 |
| polyphenol oxidase affects normal nodule development in red clover (trifolium pratense l.). | polyphenol oxidase (ppo) may have multiple functions in tissues depending on its cellular or tissue localization. here we use ppo rnai transformants of red clover (trifolium pratense) to determine the role ppo plays in normal development of plants, and especially in n2-fixing nodules. in red clover, ppo was not essential for either growth or nodule production, or for nodule function in plants grown under optimal, n-free conditions. however, absence of ppo resulted in a more reduced environment i ... | 2014 | 25566275 |
| the phosphate transporter pht4;1 is a salicylic acid regulator likely controlled by the circadian clock protein cca1. | the small phenolic compound salicylic acid (sa) plays a critical role in plant defense against broad-spectrum of pathogens. the phosphate transporter gene pht4;1 was previously shown to affect sa-mediated defense and its expression is regulated by the circadian clock. to further understand how pht4;1 affects sa accumulation, here we analyzed the genetic interactions between the gain-of-function mutant pht4;1-1 and several known sa mutants, including sid2-1, ald1-1, eds5-3, and pad4-1. the geneti ... | 2014 | 25566276 |
| molecular locks and keys: the role of small molecules in phytohormone research. | plant adaptation, growth and development rely on the integration of many environmental and endogenous signals that collectively determine the overall plant phenotypic plasticity. plant signaling molecules, also known as phytohormones, are fundamental to this process. these molecules act at low concentrations and regulate multiple aspects of plant fitness and development via complex signaling networks. by its nature, phytohormone research lies at the interface between chemistry and biology. class ... | 2014 | 25566283 |
| plasma membrane protein trafficking in plant-microbe interactions: a plant cell point of view. | in order to ensure their physiological and cellular functions, plasma membrane (pm) proteins must be properly conveyed from their site of synthesis, i.e., the endoplasmic reticulum, to their final destination, the pm, through the secretory pathway. pm protein homeostasis also relies on recycling and/or degradation, two processes that are initiated by endocytosis. vesicular membrane trafficking events to and from the pm have been shown to be altered when plant cells are exposed to mutualistic or ... | 2014 | 25566303 |
| interactions of xanthomonas type-iii effector proteins with the plant ubiquitin and ubiquitin-like pathways. | in eukaryotes, regulated protein turnover is required during many cellular processes, including defense against pathogens. ubiquitination and degradation of ubiquitinated proteins via the ubiquitin-proteasome system (ups) is the main pathway for the turnover of intracellular proteins in eukaryotes. the extensive utilization of the ups in host cells makes it an ideal pivot for the manipulation of cellular processes by pathogens. like many other gram-negative bacteria, xanthomonas species secrete ... | 2014 | 25566304 |
| coinfection rates in φ6 bacteriophage are enhanced by virus-induced changes in host cells. | two or more viruses infecting the same host cell can interact in ways that profoundly affect disease dynamics and control, yet the factors determining coinfection rates are incompletely understood. previous studies have focused on the mechanisms that viruses use to suppress coinfection, but recently the phenomenon of enhanced coinfection has also been documented. in the experiments described here, we explore the hypothesis that enhanced coinfection rates in the bacteriophage φ6 are achieved by v ... | 2008 | 25567844 |
| coinfection rates in φ6 bacteriophage are enhanced by virus-induced changes in host cells. | two or more viruses infecting the same host cell can interact in ways that profoundly affect disease dynamics and control, yet the factors determining coinfection rates are incompletely understood. previous studies have focused on the mechanisms that viruses use to suppress coinfection, but recently the phenomenon of enhanced coinfection has also been documented. in the experiments described here, we explore the hypothesis that enhanced coinfection rates in the bacteriophage φ6 are achieved by v ... | 2008 | 25567844 |
| context-dependent effects of induced resistance under co-infection in a plant-pathogen interaction. | the ability of a parasite strain to establish and grow on its host may be drastically altered by simultaneous infection by other parasite strains, and dynamics under multiple infection have been suggested to be a major force driving pathogen evolution. here, i studied whether hosts' induced defenses mediate dynamics of multiple infection of the fungal pathogen, podosphaera plantaginis, infecting plantago lanceolata. a laboratory study of sequential infections, where interaction between pathogen ... | 2011 | 25568016 |
| protein poly(adp-ribosyl)ation regulates arabidopsis immune gene expression and defense responses. | perception of microbe-associated molecular patterns (mamps) elicits transcriptional reprogramming in hosts and activates defense to pathogen attacks. the molecular mechanisms underlying plant pattern-triggered immunity remain elusive. a genetic screen identified arabidopsis poly(adp-ribose) glycohydrolase 1 (atparg1) mutant with elevated immune gene expression upon multiple mamp and pathogen treatments. poly(adp-ribose) glycohydrolase (parg) is predicted to remove poly(adp-ribose) polymers on ac ... | 2015 | 25569773 |
| in silico detection of virulence gene homologues in the human pathogen sphingomonas spp. | there is an ongoing debate about the clinical significance of sphingomonas paucimobilis as a virulent bacterial pathogen. in the present study, we investigated the presence of different virulence factors and genes in sphingomonas bacteria. we utilized phylogenetic, comparative genomics and bioinformatics analysis to investigate the potentiality of sphingomonas bacteria as virulent pathogenic bacteria. the 16s ribosomal rna gene (16s rdna) phylogenetic tree showed that the closest bacterial taxon ... | 2014 | 25574122 |
| isolation and characterization of a secoiridoid derivative from two-phase olive waste (alperujo). | a secoiridoid derivative was isolated from the ethyl acetate extract of two-phase olive waste (alperujo). the structure of this compound was fully characterized as s-trans-(e)-3-(1-oxobut-2-en-2-yl)glutaric acid. the spectroscopic data, including one- and two-dimensional nuclear magnetic resonance, mass spectrometry, infrared analysis, and ultraviolet spectrum, were showed. the origin of this compound has not been previously studied, although it most likely results from the breakdown of the oleu ... | 2015 | 25574580 |
| genetic determinants of reutericyclin biosynthesis in lactobacillus reuteri. | reutericyclin is a unique antimicrobial tetramic acid produced by some strains of lactobacillus reuteri. this study aimed to identify the genetic determinants of reutericyclin biosynthesis. comparisons of the genomes of reutericyclin-producing l. reuteri strains with those of non-reutericyclin-producing strains identified a genomic island of 14 open reading frames (orfs) including genes coding for a nonribosomal peptide synthetase (nrps), a polyketide synthase (pks), homologues of phla, phlb, an ... | 2015 | 25576609 |
| designer cell signal processing circuits for biotechnology. | microorganisms are able to respond effectively to diverse signals from their environment and internal metabolism owing to their inherent sophisticated information processing capacity. a central aim of synthetic biology is to control and reprogramme the signal processing pathways within living cells so as to realise repurposed, beneficial applications ranging from disease diagnosis and environmental sensing to chemical bioproduction. to date most examples of synthetic biological signal processing ... | 2015 | 25579192 |
| membrane-localized extra-large g proteins and gbg of the heterotrimeric g proteins form functional complexes engaged in plant immunity in arabidopsis. | in animals, heterotrimeric g proteins, comprising ga, gb, and gg subunits, are molecular switches whose function tightly depends on ga and gbg interaction. intriguingly, in arabidopsis (arabidopsis thaliana), multiple defense responses involve gbg, but not ga. we report here that the gbg dimer directly partners with extra-large g proteins (xlgs) to mediate plant immunity. arabidopsis mutants deficient in xlgs, gb, and gg are similarly compromised in several pathogen defense responses, including ... | 2015 | 25588736 |
| bacterial flagella: twist and stick, or dodge across the kingdoms. | the flagellum organelle is an intricate multiprotein assembly best known for its rotational propulsion of bacteria. however, recent studies have expanded our knowledge of other functions in pathogenic contexts, particularly adherence and immune modulation, e.g., for salmonella enterica, campylobacter jejuni, pseudomonas aeruginosa, and escherichia coli. flagella-mediated adherence is important in host colonisation for several plant and animal pathogens, but the specific interactions that promote ... | 2015 | 25590430 |
| composition, formation, and regulation of the cytosolic c-ring, a dynamic component of the type iii secretion injectisome. | many gram-negative pathogens employ a type iii secretion injectisome to translocate effector proteins into eukaryotic host cells. while the structure of the distal "needle complex" is well documented, the composition and role of the functionally important cytosolic complex remain less well understood. using functional fluorescent fusions, we found that the c-ring, an essential and conserved cytosolic component of the system, is composed of ~22 copies of sctq (yscq in yersinia enterocolitica), wh ... | 2015 | 25591178 |
| hessian fly larval feeding triggers enhanced polyamine levels in susceptible but not resistant wheat. | hessian fly (mayetiola destructor), a member of the gall midge family, is one of the most destructive pests of wheat (triticum aestivum) worldwide. probing of wheat plants by the larvae results in either an incompatible (avirulent larvae, resistant plant) or a compatible (virulent larvae, susceptible plant) interaction. virulent larvae induce the formation of a nutritive tissue, resembling the inside surface of a gall, in susceptible wheat. these nutritive cells are a rich source of proteins and ... | 2015 | 25592131 |
| characterization of mirnas associated with botrytis cinerea infection of tomato leaves. | botrytis cinerea pers. fr. is an important pathogen causing stem rot in tomatoes grown indoors for extended periods. micrornas (mirnas) have been reported as gene expression regulators related to several stress responses and b. cinerea infection in tomato. however, the function of mirnas in the resistance to b. cinerea remains unclear. | 2015 | 25592487 |
| quorum sensing triggers the stochastic escape of individual cells from pseudomonas putida biofilms. | the term 'quorum sensing' (qs) is generally used to describe the phenomenon that bacteria release and perceive signal molecules to coordinate cooperative behaviour in response to their population size. qs-based communication has therefore been considered a social trait. here we show that qs signals (n-acyl-homoserine lactones, ahls) are stochastically produced in young biofilms of pseudomonas putida and act mainly as self-regulatory signals rather than inducing neighbouring cells. we demonstrate ... | 2015 | 25592773 |
| rhizosphere microbial community composition affects cadmium and zinc uptake by the metal-hyperaccumulating plant arabidopsis halleri. | the remediation of metal-contaminated soils by phytoextraction depends on plant growth and plant metal accessibility. soil microorganisms can affect the accumulation of metals by plants either by directly or indirectly stimulating plant growth and activity or by (im)mobilizing and/or complexing metals. understanding the intricate interplay of metal-accumulating plants with their rhizosphere microbiome is an important step toward the application and optimization of phytoremediation. we compared t ... | 2015 | 25595759 |
| image-based phenotyping of plant disease symptoms. | plant diseases cause significant reductions in agricultural productivity worldwide. disease symptoms have deleterious effects on the growth and development of crop plants, limiting yields and making agricultural products unfit for consumption. for many plant-pathogen systems, we lack knowledge of the physiological mechanisms that link pathogen infection and the production of disease symptoms in the host. a variety of quantitative high-throughput image-based methods for phenotyping plant growth a ... | 2014 | 25601871 |
| image-based phenotyping of plant disease symptoms. | plant diseases cause significant reductions in agricultural productivity worldwide. disease symptoms have deleterious effects on the growth and development of crop plants, limiting yields and making agricultural products unfit for consumption. for many plant-pathogen systems, we lack knowledge of the physiological mechanisms that link pathogen infection and the production of disease symptoms in the host. a variety of quantitative high-throughput image-based methods for phenotyping plant growth a ... | 2014 | 25601871 |
| the mrna decay factor pat1 functions in a pathway including map kinase 4 and immune receptor summ2. | multi-layered defense responses are activated in plants upon recognition of invading pathogens. transmembrane receptors recognize conserved pathogen-associated molecular patterns (pamps) and activate map kinase cascades, which regulate changes in gene expression to produce appropriate immune responses. for example, arabidopsis map kinase 4 (mpk4) regulates the expression of a subset of defense genes via at least one wrky transcription factor. we report here that mpk4 is found in complexes in viv ... | 2015 | 25603932 |
| abscisic acid negatively interferes with basal defence of barley against magnaporthe oryzae. | plant hormones are well known regulators which balance plant responses to abiotic and biotic stresses. we investigated the role of abscisic acid (aba) in resistance of barley (hordeum vulgare l.) against the plant pathogenic fungus magnaporthe oryzae. | 2015 | 25604965 |
| type iv pilus glycosylation mediates resistance of pseudomonas aeruginosa to opsonic activities of the pulmonary surfactant protein a. | pseudomonas aeruginosa is a major bacterial pathogen commonly associated with chronic lung infections in cystic fibrosis (cf). previously, we have demonstrated that the type iv pilus (tfp) of p. aeruginosa mediates resistance to antibacterial effects of pulmonary surfactant protein a (sp-a). interestingly, p. aeruginosa strains with group i pilins are o-glycosylated through the tfpo glycosyltransferase with a single subunit of o-antigen (o-ag). importantly, tfpo-mediated o-glycosylation is impor ... | 2015 | 25605768 |
| the phylogenetically-related pattern recognition receptors efr and xa21 recruit similar immune signaling components in monocots and dicots. | during plant immunity, surface-localized pattern recognition receptors (prrs) recognize pathogen-associated molecular patterns (pamps). the transfer of prrs between plant species is a promising strategy for engineering broad-spectrum disease resistance. thus, there is a great interest in understanding the mechanisms of prr-mediated resistance across different plant species. two well-characterized plant prrs are the leucine-rich repeat receptor kinases (lrr-rks) efr and xa21 from arabidopsis thal ... | 2015 | 25607985 |
| redundancy and metabolic function of the glutamine synthetase gene family in poplar. | glutamine synthetase (gs; ec: 6.3.1.2, l-glutamate: ammonia ligase adp-forming) is a key enzyme in ammonium assimilation and metabolism in higher plants. in poplar, the gs family is organized in 4 groups of duplicated genes, 3 of which code for cytosolic gs isoforms (gs1.1, gs1.2 and gs1.3) and one group that codes for the choroplastic gs isoform (gs2). our previous work suggested that gs duplicates may have been retained to increase the amount of enzyme in a particular cell type. | 2015 | 25608602 |
| evaluation of methods to purify virus-like particles for metagenomic sequencing of intestinal viromes. | viruses are a significant component of the intestinal microbiota in mammals. in recent years, advances in sequencing technologies and data analysis techniques have enabled detailed metagenomic studies investigating intestinal viromes (collections of bacteriophage and eukaryotic viral nucleic acids) and their potential contributions to the ecology of the microbiota. an important component of virome studies is the isolation and purification of virus-like particles (vlps) from intestinal contents o ... | 2015 | 25608871 |
| the arabidopsis transcription factor brassinosteroid insensitive1-ethyl methanesulfonate-suppressor1 is a direct substrate of mitogen-activated protein kinase6 and regulates immunity. | pathogen-associated molecular patterns (pamps) are recognized by plant pattern recognition receptors to activate pamp-triggered immunity (pti). mitogen-activated protein kinases (mapks), as well as other cytoplasmic kinases, integrate upstream immune signals and, in turn, dissect pti signaling via different substrates to regulate defense responses. however, only a few direct substrates of these signaling kinases have been identified. here, we show that pamp perception enhances phosphorylation of ... | 2015 | 25609555 |
| a large-scale genetic screen for mutants with altered salicylic acid accumulation in arabidopsis. | salicylic acid (sa) is a key defense signal molecule against biotrophic and hemibiotrophic pathogens in plants, but how sa is synthesized in plant cells still remains elusive. identification of new components involved in pathogen-induced sa accumulation would help address this question. to this end, we performed a large-scale genetic screen for mutants with altered sa accumulation during pathogen infection in arabidopsis using a bacterial biosensor acinetobacter sp. adpwh_lux-based sa quantifica ... | 2014 | 25610446 |
| a large-scale genetic screen for mutants with altered salicylic acid accumulation in arabidopsis. | salicylic acid (sa) is a key defense signal molecule against biotrophic and hemibiotrophic pathogens in plants, but how sa is synthesized in plant cells still remains elusive. identification of new components involved in pathogen-induced sa accumulation would help address this question. to this end, we performed a large-scale genetic screen for mutants with altered sa accumulation during pathogen infection in arabidopsis using a bacterial biosensor acinetobacter sp. adpwh_lux-based sa quantifica ... | 2014 | 25610446 |
| bcgs1, a glycoprotein from botrytis cinerea, elicits defence response and improves disease resistance in host plants. | in this study, a necrosis-inducing protein was purified from the culture filtrate of the necrotrophic fungus botrytis cinerea bc-98 strain. secreted proteins were collected and fractionated by liquid chromatography. the fraction with the highest necrosis-inducing activity was further purified. a glycoprotein named bcgs1 was identified by 2d electrophoresis and mass spectrometry. the bcgs1 protein consisted of 672 amino acids with a theoretical molecular weight of 70.487 kda. functional domain an ... | 2015 | 25613865 |
| revealing shared and distinct gene network organization in arabidopsis immune responses by integrative analysis. | pattern-triggered immunity (pti) and effector-triggered immunity (eti) are two main plant immune responses to counter pathogen invasion. genome-wide gene network organizing principles leading to quantitative differences between pti and eti have remained elusive. we combined an advanced machine learning method and modular network analysis to systematically characterize the organizing principles of arabidopsis (arabidopsis thaliana) pti and eti at three network resolutions. at the single network n ... | 2015 | 25614062 |
| regulation of oncogene expression in t-dna-transformed host plant cells. | virulent agrobacterium tumefaciens strains integrate their t-dna into the plant genome where the encoded agrobacterial oncogenes are expressed and cause crown gall disease. essential for crown gall development are iaah (indole-3-acetamide hydrolase), iaam (tryptophan monooxygenase) and ipt (isopentenyl transferase), which encode enzymes for the biosynthesis of auxin (iaah, iaam) and cytokinin (ipt). although these oncogenes are well studied as the tumor-inducing principle, nothing is known about ... | 2015 | 25615824 |
| a truncated nlr protein, tir-nbs2, is required for activated defense responses in the exo70b1 mutant. | during exocytosis, the evolutionarily conserved exocyst complex tethers golgi-derived vesicles to the target plasma membrane, a critical function for secretory pathways. here we show that exo70b1 loss-of-function mutants express activated defense responses upon infection and express enhanced resistance to fungal, oomycete and bacterial pathogens. in a screen for mutants that suppress exo70b1 resistance, we identified nine alleles of tir-nbs2 (tn2), suggesting that loss-of-function of exo70b1 lea ... | 2015 | 25617755 |
| the arabidopsis ceramidase atacer functions in disease resistance and salt tolerance. | ceramidases hydrolyze ceramide into sphingosine and fatty acids. in mammals, ceramidases function as key regulators of sphingolipid homeostasis, but little is known about their roles in plants. here we characterize the arabidopsis ceramidase atacer, a homolog of human alkaline ceramidases. the acer-1 t-dna insertion mutant has pleiotropic phenotypes, including reduction of leaf size, dwarfing and an irregular wax layer, compared with wild-type plants. quantitative sphingolipid profiling showed t ... | 2015 | 25619405 |
| endophytic fungi: a reservoir of antibacterials. | multidrug drug resistant bacteria are becoming increasingly problematic particularly in the under developed countries of the world. the most important microorganisms that have seen a geometric rise in numbers are methicillin resistant staphylococcus aureus, vancomycin resistant enterococcus faecium, penicillin resistant streptococcus pneumonia and multiple drug resistant tubercule bacteria to name a just few. new drug scaffolds are essential to tackle this every increasing problem. these scaffol ... | 2014 | 25620957 |
| endophytic fungi: a reservoir of antibacterials. | multidrug drug resistant bacteria are becoming increasingly problematic particularly in the under developed countries of the world. the most important microorganisms that have seen a geometric rise in numbers are methicillin resistant staphylococcus aureus, vancomycin resistant enterococcus faecium, penicillin resistant streptococcus pneumonia and multiple drug resistant tubercule bacteria to name a just few. new drug scaffolds are essential to tackle this every increasing problem. these scaffol ... | 2014 | 25620957 |
| some things get better with age: differences in salicylic acid accumulation and defense signaling in young and mature arabidopsis. | in arabidopsis, much of what we know about the phytohormone salicylic acid (sa) and its role in plant defense comes from experiments using young plants. we are interested in understanding why young plants are susceptible to virulent strains of pseudomonas syringae, while mature plants exhibit a robust defense response known as age-related resistance (arr). sa-mediated signaling is important for defense in young plants, however, arr occurs independently of the defense regulators npr1 and why1. fu ... | 2014 | 25620972 |
| some things get better with age: differences in salicylic acid accumulation and defense signaling in young and mature arabidopsis. | in arabidopsis, much of what we know about the phytohormone salicylic acid (sa) and its role in plant defense comes from experiments using young plants. we are interested in understanding why young plants are susceptible to virulent strains of pseudomonas syringae, while mature plants exhibit a robust defense response known as age-related resistance (arr). sa-mediated signaling is important for defense in young plants, however, arr occurs independently of the defense regulators npr1 and why1. fu ... | 2014 | 25620972 |
| structural biology of innate immunity. | innate immune responses depend on timely recognition of pathogenic or danger signals by multiple cell surface or cytoplasmic receptors and transmission of signals for proper counteractions through adaptor and effector molecules. at the forefront of innate immunity are four major signaling pathways, including those elicited by toll-like receptors, rig-i-like receptors, inflammasomes, or cgas, each with its own cellular localization, ligand specificity, and signal relay mechanism. they collectivel ... | 2015 | 25622194 |
| pseudomonas syringae effector avrpphb suppresses avrb-induced activation of rpm1 but not avrrpm1-induced activation. | the pseudomonas syringae effector avrb triggers a hypersensitive resistance response in arabidopsis and soybean plants expressing the disease resistance (r) proteins rpm1 and rpg1b, respectively. in arabidopsis, avrb induces rpm1-interacting protein kinase (ripk) to phosphorylate a disease regulator known as rin4, which subsequently activates rpm1-mediated defenses. here, we show that avrpphb can suppress activation of rpm1 by avrb and this suppression is correlated with the cleavage of ripk by ... | 2015 | 25625821 |
| the relevance of nanoscale biological fragments for ice nucleation in clouds. | most studies of the role of biological entities as atmospheric ice-nucleating particles have focused on relatively rare supermicron particles such as bacterial cells, fungal spores and pollen grains. however, it is not clear that there are sufficient numbers of these particles in the atmosphere to strongly influence clouds. here we show that the ice-nucleating activity of a fungus from the ubiquitous genus fusarium is related to the presence of nanometre-scale particles which are far more numero ... | 2015 | 25626414 |
| the bacterial alarmone (p)ppgpp is required for virulence and controls cell size and survival of pseudomonas syringae on plants. | the stringent response, mediated by second messenger (p)ppgpp, results in swift and massive transcriptional reprogramming under nutrient limited conditions. in this study, the role of (p)ppgpp on virulence of pseudomonas syringae pv. syringae b728a (pssb728a) was investigated. the virulence of the rela/spot (ppgpp(0) ) double mutant was completely impaired on bean, and bacterial growth was significantly reduced, suggesting that (p)ppgpp is required for full virulence of p. syringae. expression o ... | 2015 | 25626964 |
| ptrwrky73, a salicylic acid-inducible poplar wrky transcription factor, is involved in disease resistance in arabidopsis thaliana. | a salicylic acid-inducible wrky gene, ptrwrky73, from populus trichocarpa , was isolated and characterized. overexpression of ptrwrky73 in arabidopsis thaliana increased resistance to biotrophic pathogens but reduced resistance against necrotrophic pathogens. wrky transcription factors are commonly involved in plant defense responses. however, limited information is available about the roles of the wrky genes in poplar defense. in this study, we isolated a salicylic acid (sa)-inducible wrky gene ... | 2015 | 25627252 |
| imposed glutathione-mediated redox switch modulates the tobacco wound-induced protein kinase and salicylic acid-induced protein kinase activation state and impacts on defence against pseudomonas syringae. | the role of the redox-active tripeptide glutathione in plant defence against pathogens has been studied extensively; however, the impact of changes in cellular glutathione redox potential on signalling processes during defence reactions has remained elusive. this study explored the impact of elevated glutathione content on the cytosolic redox potential and on early defence signalling at the level of mitogen-activated protein kinases (mapks), as well as on subsequent defence reactions, including ... | 2015 | 25628332 |
| root inoculation with pseudomonas putida kt2440 induces transcriptional and metabolic changes and systemic resistance in maize plants. | pseudomonas putida kt2440 (kt2440) rhizobacteria colonize a wide range of plants. they have been extensively studied for their capacity to adhere to maize seeds, to tolerate toxic secondary metabolites produced by maize roots and to be attracted by maize roots. however, the response of maize plants to kt2440 colonization has not been investigated yet. maize roots were inoculated with kt2440 and the local (roots) and systemic (leaves) early plant responses were investigated. the colonization beha ... | 2014 | 25628626 |
| root inoculation with pseudomonas putida kt2440 induces transcriptional and metabolic changes and systemic resistance in maize plants. | pseudomonas putida kt2440 (kt2440) rhizobacteria colonize a wide range of plants. they have been extensively studied for their capacity to adhere to maize seeds, to tolerate toxic secondary metabolites produced by maize roots and to be attracted by maize roots. however, the response of maize plants to kt2440 colonization has not been investigated yet. maize roots were inoculated with kt2440 and the local (roots) and systemic (leaves) early plant responses were investigated. the colonization beha ... | 2014 | 25628626 |
| the family of lsu-like proteins. | the plant response to sulfur deficiency includes extensive metabolic changes which can be monitored at various levels (transcriptome, proteome, metabolome) even before the first visible symptoms of sulfur starvation appear. four members of the plant-specific lsu (response to low sulfur) gene family occur in arabidopsis thaliana (lsu1-4). variable numbers of lsu genes occur in other plant species but they were studied only in arabidopsis and tobacco. three out of four of the arabidopsis lsu genes ... | 2014 | 25628631 |
| the family of lsu-like proteins. | the plant response to sulfur deficiency includes extensive metabolic changes which can be monitored at various levels (transcriptome, proteome, metabolome) even before the first visible symptoms of sulfur starvation appear. four members of the plant-specific lsu (response to low sulfur) gene family occur in arabidopsis thaliana (lsu1-4). variable numbers of lsu genes occur in other plant species but they were studied only in arabidopsis and tobacco. three out of four of the arabidopsis lsu genes ... | 2014 | 25628631 |
| β-glucans and eicosapolyenoic acids as mamps in plant-oomycete interactions: past and present. | branched β-1,3-glucans and the eicosapolyenoic acids (ep) are among the best characterized oomycete elicitors that trigger innate immune responses in plants. these elicitors were identified over three decades ago, and they were useful in the study of the sequence of physiological, biochemical and molecular events that induce resistance in plants. however, in spite of the cross-kingdom parallels where these molecules are well-characterized as immune system modulators in animals, their perception ... | 2014 | 25628639 |
| β-glucans and eicosapolyenoic acids as mamps in plant-oomycete interactions: past and present. | branched β-1,3-glucans and the eicosapolyenoic acids (ep) are among the best characterized oomycete elicitors that trigger innate immune responses in plants. these elicitors were identified over three decades ago, and they were useful in the study of the sequence of physiological, biochemical and molecular events that induce resistance in plants. however, in spite of the cross-kingdom parallels where these molecules are well-characterized as immune system modulators in animals, their perception ... | 2014 | 25628639 |
| involvement of calmodulin in regulation of primary root elongation by n-3-oxo-hexanoyl homoserine lactone in arabidopsis thaliana. | many bacteria use signal molecules of low molecular weight to monitor their local population density and to coordinate their collective behavior in a process called "quorum sensing" (qs). n-acyl-homoserine lactones (ahls) are the primary qs signals among gram-negative bacteria. ahl-mediated qs plays an essential role in diverse bacterial physiological processes. recent evidence shows that plants are able to sense bacterial ahls and respond to them appropriately. however, little is known about th ... | 2014 | 25628641 |
| involvement of calmodulin in regulation of primary root elongation by n-3-oxo-hexanoyl homoserine lactone in arabidopsis thaliana. | many bacteria use signal molecules of low molecular weight to monitor their local population density and to coordinate their collective behavior in a process called "quorum sensing" (qs). n-acyl-homoserine lactones (ahls) are the primary qs signals among gram-negative bacteria. ahl-mediated qs plays an essential role in diverse bacterial physiological processes. recent evidence shows that plants are able to sense bacterial ahls and respond to them appropriately. however, little is known about th ... | 2014 | 25628641 |
| the search for therapeutic bacteriophages uncovers one new subfamily and two new genera of pseudomonas-infecting myoviridae. | in a previous study, six virulent bacteriophages pak_p1, pak_p2, pak_p3, pak_p4, pak_p5 and cha_p1 were evaluated for their in vivo efficacy in treating pseudomonas aeruginosa infections using a mouse model of lung infection. here, we show that their genomes are closely related to five other pseudomonas phages and allow a subdivision into two clades, pak_p1-like and kpp10-like viruses, based on differences in genome size, %gc and genomic contents, as well as number of trnas. these two clades are ... | 2015 | 25629728 |
| lipopeptides as the antifungal and antibacterial agents: applications in food safety and therapeutics. | a lot of crops are destroyed by the phytopathogens such as fungi, bacteria, and yeast leading to economic losses to the farmers. members of the bacillus genus are considered as the factories for the production of biologically active molecules that are potential inhibitors of growth of phytopathogens. plant diseases constitute an emerging threat to global food security. many of the currently available antimicrobial agents for agriculture are highly toxic and nonbiodegradable and thus cause extend ... | 2015 | 25632392 |
| identification of qtls controlling resistance to pseudomonas syringae pv. tomato race 1 strains from the wild tomato, solanum habrochaites la1777. | screening of wild tomato accessions revealed a source of resistance to pseudomonas syringe pv. tomato race 1 from solanum habrochaites and facilitated mapping of qtls controlling disease resistance. pseudomonas syringae pv. tomato (pst) causes bacterial speck of tomato, which is one of the most persistent bacterial diseases in tomato worldwide. existing pst populations have overcome genetic resistance mediated by the tomato genes pto and prf. the objective of this study was to identify sources o ... | 2015 | 25634105 |
| sequence-specific cleavage of dsrna by mini-iii rnase. | ribonucleases (rnases) play a critical role in rna processing and degradation by hydrolyzing phosphodiester bonds (exo- or endonucleolytically). many rnases that cut rna internally exhibit substrate specificity, but their target sites are usually limited to one or a few specific nucleotides in single-stranded rna and often in a context of a particular three-dimensional structure of the substrate. thus far, no rnase counterparts of restriction enzymes have been identified which could cleave doubl ... | 2015 | 25634891 |
| recruitment of plant u-box13 and the pi4kβ1/β2 phosphatidylinositol-4 kinases by the small gtpase raba4b plays important roles during salicylic acid-mediated plant defense signaling in arabidopsis. | protection against microbial pathogens involves the activation of cellular immune responses in eukaryotes, and this cellular immunity likely involves changes in subcellular membrane trafficking. in eukaryotes, members of the rab gtpase family of small monomeric regulatory gtpases play prominent roles in the regulation of membrane trafficking. we previously showed that raba4b is recruited to vesicles that emerge from trans-golgi network (tgn) compartments and regulates polarized membrane traffick ... | 2015 | 25634989 |
| perturbation of maize phenylpropanoid metabolism by an avre family type iii effector from pantoea stewartii. | avre family type iii effector proteins share the ability to suppress host defenses, induce disease-associated cell death, and promote bacterial growth. however, despite widespread contributions to numerous bacterial diseases in agriculturally important plants, the mode of action of these effectors remains largely unknown. wtse is an avre family member required for the ability of pantoea stewartii ssp. stewartii (pnss) to proliferate efficiently and cause wilt and leaf blight symptoms in maize (z ... | 2015 | 25635112 |
| biochemical characterization of uronate dehydrogenases from three pseudomonads, chromohalobacter salixigens, and polaromonas naphthalenivorans. | enzyme catalysts will be vital in the development of synthetic biology approaches for converting pectinic monosaccharides from citrus and beet processing waste streams to value-added materials. we describe here the biophysical and mechanistic characterization of uronate dehydrogenases from a wide variety of bacterial sources that convert galacturonic acid, the predominate building block of pectin from these plant sources, and glucuronic acid to their corresponding dicarboxylic acids galactarate ... | 2015 | 25640726 |
| milestones in plant sulfur research on sulfur-induced-resistance (sir) in europe. | until the 1970's of the last century sulfur (s) was mainly regarded as a pollutant being the main contributor of acid rain, causing forest dieback in central europe. when clean air acts came into force at the start of the 1980's so2 contaminations in the air were consequently reduced within the next years. s changed from an unwanted pollutant into a lacking plant nutrient in agriculture since agricultural fields were no longer "fertilized" indirectly by industrial pollution. s deficiency was fir ... | 2014 | 25642233 |
| milestones in plant sulfur research on sulfur-induced-resistance (sir) in europe. | until the 1970's of the last century sulfur (s) was mainly regarded as a pollutant being the main contributor of acid rain, causing forest dieback in central europe. when clean air acts came into force at the start of the 1980's so2 contaminations in the air were consequently reduced within the next years. s changed from an unwanted pollutant into a lacking plant nutrient in agriculture since agricultural fields were no longer "fertilized" indirectly by industrial pollution. s deficiency was fir ... | 2014 | 25642233 |
| ahl-priming functions via oxylipin and salicylic acid. | collaborative action between the host plant and associated bacteria is crucial for the establishment of an efficient interaction. in bacteria, the synchronized behavior of a population is often achieved by a density-dependent communication called quorum sensing. this behavior is based on signaling molecules, which influence bacterial gene expression. n-acyl homoserine lactones (ahls) are such molecules in many gram-negative bacteria. moreover, some ahls are responsible for the beneficial effect ... | 2014 | 25642235 |
| ahl-priming functions via oxylipin and salicylic acid. | collaborative action between the host plant and associated bacteria is crucial for the establishment of an efficient interaction. in bacteria, the synchronized behavior of a population is often achieved by a density-dependent communication called quorum sensing. this behavior is based on signaling molecules, which influence bacterial gene expression. n-acyl homoserine lactones (ahls) are such molecules in many gram-negative bacteria. moreover, some ahls are responsible for the beneficial effect ... | 2014 | 25642235 |
| levansucrases of a pseudomonas syringae pathovar as catalysts for the synthesis of potentially prebiotic oligo- and polysaccharides. | gut microbiota influences more physiological and developmental processes of humans and animals than earlier expected. therefore, the possibility to shape the composition and activity of this bacterial population by prebiotics becomes especially important. inulin, a β-2,1 linked fructan polymer, from plants and fructooligosaccharides (fos) derived from it are recognized and already widely used as prebiotics while β-2,6 linked fructans have received much less attention from scientific community. i ... | 2015 | 25644638 |
| a novel pyrroloquinoline quinone-dependent 2-keto-d-glucose dehydrogenase from pseudomonas aureofaciens. | a gene encoding an enzyme similar to a pyrroloquinoline quinone (pqq)-dependent sugar dehydrogenase from filamentous fungi, which belongs to new auxiliary activities (aa) family 12 in the cazy database, was cloned from pseudomonas aureofaciens. the deduced amino acid sequence of the cloned enzyme showed only low homology to previously characterized pqq-dependent enzymes, and multiple-sequence alignment analysis showed that the enzyme lacks one of the three conserved arginine residues that functi ... | 2015 | 25645559 |
| arabidopsis hfr1 is a potential nuclear substrate regulated by the xanthomonas type iii effector xopd(xcc8004). | xopdxcc8004, a type iii effector of xanthomonas campestris pv. campestris (xcc) 8004, is considered a shorter version of the xopd, which lacks the n-terminal domain. to understand the functions of xopdxcc8004, in planta, a transgenic approach combined with inducible promoter to analyze the effects of xopdxcc8004 in arabidopsis was done. here, the expression of xopdxcc8004, in arabidopsis elicited the accumulation of host defense-response genes. these molecular changes were dependent on salicylic ... | 2015 | 25647296 |
| downy mildew disease promotes the colonization of romaine lettuce by escherichia coli o157:h7 and salmonella enterica. | downy mildew, a plant disease caused by the oomycete bremia lactucae, is endemic in many lettuce-growing regions of the world. invasion by plant pathogens may create new portals and opportunities for microbial colonization of plants. the occurrence of outbreaks of escherichia coli o157:h7 (eco157) and salmonella enterica typhimurium (s. typhimurium) infections linked to lettuce prompted us to investigate the role of downy mildew in the colonization of romaine lettuce by these human pathogens und ... | 2015 | 25648408 |
| expanding the enzyme universe: accessing non-natural reactions by mechanism-guided directed evolution. | high selectivity and exquisite control over the outcome of reactions entice chemists to use biocatalysts in organic synthesis. however, many useful reactions are not accessible because they are not in nature's known repertoire. in this review, we outline an evolutionary approach to engineering enzymes to catalyze reactions not found in nature. we begin with examples of how nature has discovered new catalytic functions and how such evolutionary progression has been recapitulated in the laboratory ... | 2015 | 25649694 |
| dissection of two complex clusters of resistance genes in lettuce (lactuca sativa). | of the over 50 phenotypic resistance genes mapped in lettuce, 25 colocalize to three major resistance clusters (mrc) on chromosomes 1, 2, and 4. similarly, the majority of candidate resistance genes encoding nucleotide binding-leucine rich repeat (nlr) proteins genetically colocalize with phenotypic resistance loci. mrc1 and mrc4 span over 66 and 63 mb containing 84 and 21 nlr-encoding genes, respectively, as well as 765 and 627 genes that are not related to nlr genes. forward and reverse geneti ... | 2015 | 25650829 |
| copper tolerance and virulence in bacteria. | copper (cu) is an essential trace element for all aerobic organisms. it functions as a cofactor in enzymes that catalyze a wide variety of redox reactions due to its ability to cycle between two oxidation states, cu(i) and cu(ii). this same redox property of copper has the potential to cause toxicity if copper homeostasis is not maintained. studies suggest that the toxic properties of copper are harnessed by the innate immune system of the host to kill bacteria. to counter such defenses, bacteri ... | 2015 | 25652326 |
| genome-wide gene order distances support clustering the gram-positive bacteria. | initially using 143 genomes, we developed a method for calculating the pair-wise distance between prokaryotic genomes using a monte carlo method to estimate the conservation of gene order. the method was based on repeatedly selecting five or six non-adjacent random orthologs from each of two genomes and determining if the chosen orthologs were in the same order. the raw distances were then corrected for gene order convergence using an adaptation of the jukes-cantor model, as well as using the co ... | 2015 | 25653643 |