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diversity and distribution of n-acylhomoserine lactone (ahl)-degrading activity and ahl-lactonase (aiim) in genus microbacterium.n-acylhomoserine lactone (ahl)-degrading enzyme, aiim, was identified from the potato leaf-associated microbacterium testaceum stlb037. in this study, we cloned eight aiim gene homologues from other ahl-degrading microbacterium strains. the similarity of the chromosomal locus of the aiim gene is associated with the phylogenetic classification based on 16s rrna. degenerate pcr revealed that the aiim gene was only conserved in ahl-degrading microbacterium strains, but not in fifteen microbacterium ...201222446311
metals bioleaching from electronic waste by chromobacterium violaceum and pseudomonads sp.these days, electronic waste needs to be taken into consideration due to its materials content, but due to the heterogeneity of the metals present, reprocessing of electronic waste is quite limited. the bioleaching of metals from electronic waste was investigated by using cyanogenic bacterial strains (chromobacterium violaceum, pseudomonas aeruginosa and pseudomonas fluorescens). a two-step bioleaching process was followed under cyanide-forming conditions for maximum metals mobilization. both si ...201222452961
hmup is a coactivator of irr-dependent expression of heme utilization genes in bradyrhizobium japonicum.utilization of heme as an iron source by bradyrhizobium japonicum involves induction of the outer membrane heme receptor gene hmur and other genes within the heme utilization locus. here, we discovered the hmup gene located upstream of hmur and transcribed divergently from it along with hmutuv. hmup encodes a small protein that accumulated under iron limitation and is transcriptionally controlled by the global iron-responsive regulator irr, as were all genes within the heme utilization locus. cr ...201222505680
computer-based annotation of putative arac/xyls-family transcription factors of known structure but unknown function.currently, about 20 crystal structures per day are released and deposited in the protein data bank. a significant fraction of these structures is produced by research groups associated with the structural genomics consortium. the biological function of many of these proteins is generally unknown or not validated by experiment. therefore, a growing need for functional prediction of protein structures has emerged. here we present an integrated bioinformatics method that combines sequence-based rel ...201222505803
dotu and vgrg, core components of type vi secretion systems, are essential for francisella lvs pathogenicity.the gram-negative bacterium francisella tularensis causes tularemia, a disease which requires bacterial escape from phagosomes of infected macrophages. once in the cytosol, the bacterium rapidly multiplies, inhibits activation of the inflammasome and ultimately causes death of the host cell. of importance for these processes is a 33-kb gene cluster, the francisella pathogenicity island (fpi), which is believed to encode a type vi secretion system (t6ss). in this study, we analyzed the role of th ...201222514651
functional dissection of ssef, a membrane-integral effector protein of intracellular salmonella enterica.during intracellular life, the bacterial pathogen salmonella enterica translocates a complex cocktail of effector proteins by means of the spi2-encoded type iii secretions system. the effectors jointly modify the endosomal system and vesicular transport in host cells. ssef and sseg are two effectors encoded by genes within salmonella pathogenicity island 2 and both effector associate with endosomal membranes and microtubules and are involved in the formation of salmonella-induced filaments. our ...201222529968
thailandepsins are new small molecule class i hdac inhibitors with potent cytotoxic activity in ovarian cancer cells: a preclinical study of epigenetic ovarian cancer therapy.new treatment strategies are emerging to target dna damage response pathways in ovarian cancer. our group has previously shown that the class i biased hdac inhibitor romidepsin (fk228) induces dna damage response and has potent cytotoxic effects in ovarian cancer cells. here, we investigated newly discovered hdac inhibitors, thailandepsin a (tdp-a) and thailandepsin b (tdp-b), to determine the effects on cell viability, apoptosis and dna damage response in ovarian cancer cells.201222531354
inhibition of quorum sensing (qs) in yersinia enterocolitica by an orange extract rich in glycosylated flavanones.flavanones, flavonoids abundant in citrus , have been shown to interfere with quorum sensing (qs) and affect related physiological processes. we have investigated the qs-inhibitory effects of an orange extract enriched in o-glycosylated flavanones (mainly naringin, neohesperidin, and hesperidin). the qs-inhibitory capacity of this extract and its main flavanone components was first screened using the bacteriological monitoring system chromobacterium violaceum . we next examined the ability of th ...201222533445
identification of n-acyl-l-homoserine lactones produced by non-pigmented chromobacterium aquaticum cc-seya-1(t) and pigmented chromobacterium subtsugae praa4-1(t).many members of the genus chromobacterium produce violacein, a characteristic purple pigment which is induced by small diffusible n-acyl homoserine lactones (ahl) quorum-sensing molecules. in this study, the production of ahl of the non-pigmented c. aquaticum cc-seya-1(t) and the pigmented c. subtsugae praa4-1(t) were determined by using a cv026 biosensor assay. the profile of ahl was identified from the extracts of stationary phase cultures using gas chromatography-mass spectroscopy (gc-ms) and ...201122558542
rnd type efflux pump system mexab-oprm of pseudomonas aeruginosa selects bacterial languages, 3-oxo-acyl-homoserine lactones, for cell-to-cell communication.bacteria release a wide variety of small molecules including cell-to-cell signaling compounds. gram-negative bacteria use a variety of self-produced autoinducers such as acylated homoserine lactones (acyl-hsls) as signal compounds for quorum sensing (qs) within and between bacterial species. qs plays a significant role in the pathogenesis of infectious diseases and in beneficial symbiosis by responding to acyl-hsls in pseudomonas aeruginosa. it is considered that the selection of bacterial langu ...201222574700
the presence and role of bacterial quorum sensing in activated sludge.activated sludge used for wastewater treatment globally is composed of a high-density microbial community of great biotechnological significance. in this study the presence and purpose of quorum sensing via n-acylated-l-homoserine lactones (ahls) in activated sludge was explored. the presence of n-heptanoyl-l-homoserine lactone in organic extracts of sludge was demonstrated along with activation of a luxr-based ahl monitor strain deployed in sludge, indicating ahl-mediated gene expression is act ...201222583685
regulation of innate immunity by nadph oxidase.nadph oxidase is a critical regulator of both antimicrobial host defense and inflammation. activated in nature by microbes and microbial-derived products, the phagocyte nadph oxidase is rapidly assembled, and generates reactive oxidant intermediates (rois) in response to infectious threat. chronic granulomatous disease (cgd) is an inherited disorder of the nadph oxidase characterized by recurrent and severe bacterial and fungal infections, and pathology related to excessive inflammation. studies ...201222583699
discovery and mechanism of natural products as modulators of histone acetylation.small molecules that modulate histone acetylation by targeting key enzymes mediating this posttranslational modification - histone acetyltransferases and histone deacetylases - are validated chemotherapeutic agents for the treatment of cancer. this area of research has seen a rapid increase in interest in the past decade, with the structurally diverse natural products-derived compounds at its forefront. these secondary metabolites from various biological sources target this epigenetic modificati ...201222594471
novel therapeutic agents for cutaneous t-cell lymphoma.mycosis fungoides (mf) and sezary syndrome (ss) represent the most common subtypes of primary cutaneous t-cell lymphoma (ctcl). patients with advanced mf and ss have a poor prognosis leading to an interest in the development of new therapies with targeted mechanisms of action and acceptable safety profiles. in this review we focus on such novel strategies that have changed the treatment paradigm of this rare malignancy.201222594538
identification of a third osmoprotectant transport system, the osmu system, in salmonella enterica.the growth of salmonella enterica serovar typhimurium mutants lacking the prop and prou osmoprotectant transport systems is stimulated by glycine betaine in high-osmolarity media, suggesting that this organism has an additional osmoprotectant transport system. bioinformatic analysis revealed that the genome of this organism contains a hitherto-unidentified operon, designated osmu, consisting of four genes whose products show high similarity to abc-type transport systems for osmoprotectants in ot ...201222609924
different biosynthetic pathways to fosfomycin in pseudomonas syringae and streptomyces species.fosfomycin is a wide-spectrum antibiotic that is used clinically to treat acute cystitis in the united states. the compound is produced by several strains of streptomycetes and pseudomonads. we sequenced the biosynthetic gene cluster responsible for fosfomycin production in pseudomonas syringae pb-5123. surprisingly, the biosynthetic pathway in this organism is very different from that in streptomyces fradiae and streptomyces wedmorensis. the pathways share the first and last steps, involving co ...201222615277
honaucins a-c, potent inhibitors of inflammation and bacterial quorum sensing: synthetic derivatives and structure-activity relationships.honaucins a-c were isolated from the cyanobacterium leptolyngbya crossbyana which was found overgrowing corals on the hawaiian coast. honaucin a consists of (s)-3-hydroxy-γ-butyrolactone and 4-chlorocrotonic acid, which are connected via an ester linkage. honaucin a and its two natural analogs exhibit potent inhibition of both bioluminescence, a quorum-sensing-dependent phenotype, in vibrio harveyi bb120 and lipopolysaccharide-stimulated nitric oxide production in the murine macrophage cell line ...201222633410
genetically modified strains of ralstonia eutropha h16 with β-ketothiolase gene deletions for production of copolyesters with defined 3-hydroxyvaleric acid contents.β-ketothiolases catalyze the first step of poly(3-hydroxybutyrate) [poly(3hb)] biosynthesis in bacteria by condensation of two acetyl coenzyme a (acetyl-coa) molecules to acetoacetyl-coa and also take part in the degradation of fatty acids. during growth on propionate or valerate, ralstonia eutropha h16 produces the copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [poly(3hb-co-3hv)]. in r. eutropha, 15 β-ketothiolase homologues exist. the synthesis of 3-hydroxybutyryl-coa (3hb-coa) could b ...201222636005
fk228 analogues induce fetal hemoglobin in human erythroid progenitors.fetal hemoglobin (hbf) improves the clinical severity of sickle cell disease (scd), therefore, research to identify hbf-inducing agents for treatment purposes is desirable. the focus of our study is to investigate the ability of fk228 analogues to induce hbf using a novel ku812 dual-luciferase reporter system. molecular modeling studies showed that the structure of twenty fk228 analogues with isosteric substitutions did not disturb the global structure of the molecule. using the dual-luciferase ...201222655179
molecular modeling and active site analysis of sdia homolog, a putative quorum sensor for salmonella typhimurium pathogenecity reveals specific binding patterns of ahl transcriptional regulators.salmonella typhimurium is a gram-negative bacterium responsible for human diseases including gastroenteritis and typhoid fever and its quorum sensing system is currently being intensively researched. molecular modeling and binding site analysis of sdia homolog, a putative quorum sensor of the luxr family and responsible for s. typhimurium pathogenecity revealed a high structural homology of their active site with three other luxr family proteins lasr from pseudomonas aeruginosa, trar from agroba ...201222660944
a variant quorum sensing system in aeromonas veronii mtcc 3249.we have investigated the quorum sensing control in aeromonas veronii mtcc 3249, originally isolated as a. culicicola from the midgut of culex quinquefasciatus. based on biosensor assays, the bacterium showed constant production of multiple acyl-homoserine lactones (ahls) with increasing cell-density. the luxri gene homologs, acur (a. culicicola transcriptional regulator) and acui (a. culicicola autoinducer) were successfully amplified by inverse-pcr. sequence analysis indicated acuri were diverg ...201222666003
inhibition of quorum sensing-controlled virulence factor production in pseudomonas aeruginosa pao1 by ayurveda spice clove (syzygium aromaticum) bud extract.quorum sensing controls the virulence determinants in most proteobacteria. in this work, the hexane, chloroform and methanol extracts of an ayurveda spice, namely clove (syzygium aromaticum), shown anti-quorum sensing activity. hexane and methanol extracts of clove inhibited the response of c. violaceum cv026 to exogenously supplied n-hexanoylhomoserine lactone, in turn preventing violacein production. chloroform and methanol extracts of clove significantly reduced bioluminescence production by ...201222666015
quorum quenching bacillus sonorensis isolated from soya sauce fermentation brine.an n-acylhomoserine lactone (ahl)-degrading bacterial strain, l62, was isolated from a sample of fermentation brine of chinese soya sauce by using rich medium agar supplemented with soya sauce (10% v/v). l62, a rod-shaped gram positive bacterium with amylolytic activity, was phylogentically related to bacillus sonorensis by 16s ribosomal dna and rpob sequence analyses. b. sonorensis l62 efficiently degraded n-3-oxohexanoyl homoserine lactone and n-octanoylhomoserine lactone. however, the aiia ho ...201222666018
silencing quorum sensing through extracts of melicope lunu-ankenda.quorum sensing regulates bacterial virulence determinants, therefore making it an interesting target to attenuate pathogens. in this work, we screened edible, endemic plants in malaysia for anti-quorum sensing properties. extracts from melicope lunu-ankenda (gaertn.) t. g. hartley, a malay garden salad, inhibited response of chromobacterium violaceum cv026 to n-hexanoylhomoserine lactone, thus interfering with violacein production; reduced bioluminescence expression of e. coli [psb401], disrupte ...201222666033
characterization of quorum sensing and quorum quenching soil bacteria isolated from malaysian tropical montane forest.we report the production and degradation of quorum sensing n-acyl-homoserine lactones by bacteria isolated from malaysian montane forest soil. phylogenetic analysis indicated that these isolates clustered closely to the genera of arthrobacter, bacillus and pseudomonas. quorum quenching activity was detected in six isolates of these three genera by using a series of bioassays and rapid resolution liquid chromatography analysis. biosensor screening and high resolution liquid chromatography-mass sp ...201222666062
chromobacterium violaceum ω-transaminase variant trp60cys shows increased specificity for (s)-1-phenylethylamine and 4'-substituted acetophenones, and follows swain-lupton parameterisation.for biocatalytic production of pharmaceutically important chiral amines the ω-transaminase enzymes have proven useful. engineering of these enzymes has to some extent been accomplished by rational design, but mostly by directed evolution. by use of a homology model a key point mutation in chromobacterium violaceum ω-transaminase was found upon comparison with engineered variants from homologous enzymes. the variant trp60cys gave increased specificity for (s)-1-phenylethylamine (29-fold) and 4'-s ...201222688085
determination of whether quorum quenching is a common activity in marine bacteria by analysis of cultivable bacteria and metagenomic sequences.the abundance of quorum quenching (qq) activity was evaluated in cultivable bacteria obtained from oceanic and estuarine seawater and compared with the frequency of qq enzyme sequences in the available marine metagenomic collections. the possible role of the high qq activity found among marine bacteria is discussed.201222706060
detection, characterization, and biological effect of quorum-sensing signaling molecules in peanut-nodulating bradyrhizobia.bacteria of the genus bradyrhizobium are able to establish a symbiotic relationship with peanut (arachis hypogaea) root cells and to fix atmospheric nitrogen by converting it to nitrogenous compounds. quorum sensing (qs) is a cell-cell communication mechanism employed by a variety of bacterial species to coordinate behavior at a community level through regulation of gene expression. the qs process depends on bacterial production of various signaling molecules, among which the n-acylhomoserine la ...201222736981
evaluation of anti-quorum-sensing activity of fermentation metabolites from different strains of a medicinal mushroom, phellinus igniarius.this study aimed to evaluate the different abilities of various phellinus igniarius strains inhibiting quorum sensing (qs), to search for novel qs inhibitors from them and to analyze their inhibitory activity, with a view to their possible use in controlling infections.201222739070
phase ii trial of the histone deacetylase inhibitor romidepsin in patients with recurrent/metastatic head and neck cancer.patients with advanced squamous cell carcinoma of the head and neck (scchn) have limited treatment options. inhibition of histone deacetylases (hdacs) represents a novel therapeutic approach warranting additional investigation in solid tumors.201222748449
fatty acid biosynthesis in pseudomonas aeruginosa is initiated by the faby class of β-ketoacyl acyl carrier protein synthases.the prototypical type ii fatty acid synthesis (fas) pathway in bacteria utilizes two distinct classes of β-ketoacyl synthase (kas) domains to assemble long-chain fatty acids, the kasiii domain for initiation and the kasi/ii domain for elongation. the central role of fas in bacterial viability and virulence has stimulated significant effort toward developing kas inhibitors, particularly against the kasiii domain of the β-acetoacetyl-acyl carrier protein (acp) synthase fabh. herein, we show that t ...201222753059
mlp24 (mcpx) of vibrio cholerae implicated in pathogenicity functions as a chemoreceptor for multiple amino acids.the chemotaxis of vibrio cholerae, the causative agent of cholera, has been implicated in pathogenicity. the bacterium has more than 40 genes for methyl-accepting chemotaxis protein (mcp)-like proteins (mlps). in this study, we found that glycine and at least 18 l-amino acids, including serine, arginine, asparagine, and proline, serve as attractants to the classical biotype strain o395n1. based on the sequence comparison with vibrio parahaemolyticus, we speculated that at least 17 mlps of v. cho ...201222753378
acyl-homoserine lactone-dependent eavesdropping promotes competition in a laboratory co-culture model.many proteobacteria use acyl-homoserine lactone (ahl)-mediated quorum sensing to activate the production of antibiotics at high cell density. extracellular factors like antibiotics can be considered public goods shared by individuals within a group. quorum-sensing control of antibiotic production may be important for protecting a niche or competing for limited resources in mixed bacterial communities. to begin to investigate the role of quorum sensing in interspecies competition, we developed a ...201222763647
the bacterium pantoea stewartii uses two different type iii secretion systems to colonize its plant host and insect vector.plant- and animal-pathogenic bacteria utilize phylogenetically distinct type iii secretion systems (t3ss) that produce needle-like injectisomes or pili for the delivery of effector proteins into host cells. pantoea stewartii subsp. stewartii (herein referred to as p. stewartii), the causative agent of stewart's bacterial wilt and leaf blight of maize, carries phylogenetically distinct t3sss. in addition to an hrc-hrp t3ss, known to be essential for maize pathogenesis, p. stewartii has a second t ...201222773631
paediatric chromobacterium violaceum in cambodia: the first documented case.chromobacterium violaceum infection is rarely described in southeast asian children, which may be due partly to the lack of access to adequate microbiology facilities in many areas. this case report describes the first documented case to occur in a cambodian child. an awareness of the disease and its manifestations is important as treatment can be difficult and may require prolonged courses of antimicrobials and surgery.201222785546
detection of quorum sensing signal molecules and identification of an autoinducer synthase gene among biofilm forming clinical isolates of acinetobacter spp.quorum sensing is a term that describes an environmental sensing system that allows bacteria to monitor their own population density which contributes significantly to the size and development of the biofilm. many gram negative bacteria use n-acyl-homoserine lactones as quorum sensing signal molecules. in this study, we sought to find out if the biofilm formation among clinical isolates of acinetobacter spp. is under the control of autoinducing quorum sensing molecules.201222815678
microbial regulation in gorgonian corals.gorgonian corals possess many novel natural products that could potentially mediate coral-bacterial interactions. since many bacteria use quorum sensing (qs) signals to facilitate colonization of host organisms, regulation of prokaryotic cell-to-cell communication may represent an important bacterial control mechanism. in the present study, we examined extracts of twelve species of caribbean gorgonian corals, for mechanisms that regulate microbial colonization, such as antibacterial activity and ...201222822369
quorum sensing: how bacteria can coordinate activity and synchronize their response to external signals?quorum sensing is used by a large variety of bacteria to regulate gene expression in a cell-density-dependent manner. bacteria can synchronize population behavior using small molecules called autoinducers that are produced by cognate synthases and recognized by specific receptors. quorum sensing plays critical roles in regulating diverse cellular functions in bacteria, including bioluminescence, virulence gene expression, biofilm formation, and antibiotic resistance. the best-studied autoinducer ...201222825856
rsfa (ybeb) proteins are conserved ribosomal silencing factors.the ybeb (duf143) family of uncharacterized proteins is encoded by almost all bacterial and eukaryotic genomes but not archaea. while they have been shown to be associated with ribosomes, their molecular function remains unclear. here we show that ybeb is a ribosomal silencing factor (rsfa) in the stationary growth phase and during the transition from rich to poor media. a knock-out of the rsfa gene shows two strong phenotypes: (i) the viability of the mutant cells are sharply impaired during st ...201222829778
reactive oxygen species in the signaling and adaptation of multicellular microbial communities.one of the universal traits of microorganisms is their ability to form multicellular structures, the cells of which differentiate and communicate via various signaling molecules. reactive oxygen species (ros), and hydrogen peroxide in particular, have recently become well-established signaling molecules in higher eukaryotes, but still little is known about the regulatory functions of ros in microbial structures. here we summarize current knowledge on the possible roles of ros during the developm ...201222829965
solution nmr structure of hypothetical protein cv_2116 encoded by a viral prophage element in chromobacterium violaceum.cv_2116 is a small hypothetical protein of 82 amino acids from the gram-negative coccobacillus chromobacterium violaceum. a psi-blast search using the cv_2116 sequence as a query identified only one hit (e = 2e(-07)) corresponding to a hypothetical protein or16_04617 from cupriavidus basilensis or16, which failed to provide insight into the function of cv_2116. the cv_2116 gene was cloned into the p15tvlic expression plasmid, transformed into e. coli, and (13)c- and (15)n-labeled nmr samples of ...201222837698
revised genome sequence of burkholderia thailandensis msmb43 with improved annotation.there is growing interest in discovery of novel bioactive natural products from burkholderia thailandensis. here we report a significantly improved genome sequence and reannotation of burkholderia thailandensis msmb43, which will facilitate the discovery of new natural products through genome mining and studies of the metabolic versatility of this bacterium.201222887659
extreme antimicrobial peptide and polymyxin b resistance in the genus burkholderia.cationic antimicrobial peptides and polymyxins are a group of naturally occurring antibiotics that can also possess immunomodulatory activities. they are considered a new source of antibiotics for treating infections by bacteria that are resistant to conventional antibiotics. members of the genus burkholderia, which includes various human pathogens, are inherently resistant to antimicrobial peptides. the resistance is several orders of magnitude higher than that of other gram-negative bacteria s ...201122919572
the promise of bacteriophage therapy for burkholderia cepacia complex respiratory infections.in recent times, increased attention has been given to evaluating the efficacy of phage therapy, especially in scenarios where the bacterial infectious agent of interest is highly antibiotic resistant. in this regard, phage therapy is especially applicable to infections caused by the burkholderia cepacia complex (bcc) since members of the bcc are antibiotic pan-resistant. current studies in bcc phage therapy are unique from many other avenues of phage therapy research in that the investigation i ...201122919592
the promise of bacteriophage therapy for burkholderia cepacia complex respiratory infections.in recent times, increased attention has been given to evaluating the efficacy of phage therapy, especially in scenarios where the bacterial infectious agent of interest is highly antibiotic resistant. in this regard, phage therapy is especially applicable to infections caused by the burkholderia cepacia complex (bcc) since members of the bcc are antibiotic pan-resistant. current studies in bcc phage therapy are unique from many other avenues of phage therapy research in that the investigation i ...201122919592
marine microorganisms: perspectives for getting involved in cellulosic ethanol.the production of ethanol has been considered as an alternative to replace part of the petroleum derivate. brazil and the us are the leading producers, but more environmentally friendly alternatives are needed. lignocellulose has an enormous potential but technology has to be still improve in order to economically produce ethanol. the present paper reviews the potential and problems of this technology and proposes the study of a group of microorganisms with the largest genetic pool, marine micro ...201222931793
aidc, a novel n-acylhomoserine lactonase from the potato root-associated cytophaga-flavobacteria-bacteroides (cfb) group bacterium chryseobacterium sp. strain strb126.n-acylhomoserine lactones (ahls) are used as quorum-sensing (qs) signal molecules by many gram-negative bacteria. we have reported that chryseobacterium sp. strain strb126, which was isolated from the root surface of potato, has ahl-degrading activity. in this study, we cloned and characterized the aidc gene from the genomic library of strb126. aidc has ahl-degrading activity and shows homology to several metallo-β-lactamase proteins from bacteroidetes, although not to any known ahl-degrading en ...201222941089
chemical methods to interrogate bacterial quorum sensing pathways.bacteria frequently manifest distinct phenotypes as a function of cell density in a phenomenon known as quorum sensing (qs). this intercellular signalling process is mediated by "chemical languages" comprised of low-molecular weight signals, known as autoinducers, and their cognate receptor proteins. as many of the phenotypes regulated by qs can have a significant impact on the success of pathogenic or mutualistic prokaryotic-eukaryotic interactions, there is considerable interest in methods to ...201222948815
subversion of cell signaling by pathogens.pathogens exploit several eukaryotic signaling pathways during an infection. they have evolved specific effectors and toxins to hijack host cell machinery for their own benefit. signaling molecules are preferentially targeted by pathogens because they globally regulate many cellular processes. both viruses and bacteria manipulate and control pathways that regulate host cell survival and shape, including mapk signaling, g-protein signaling, signals controlling cytoskeletal dynamics, and innate im ...201222952390
unusual long-chain n-acyl homoserine lactone production by and presence of quorum quenching activity in bacterial isolates from diseased tilapia fish.growth-dependent cell-cell communication termed quorum sensing is a key regulatory system in bacteria for controlling gene expression including virulence factors. in this study five potential bacterial pathogens including bacillus sp. w2.2, klebsiella sp. w4.2, pseudomonas sp. w3 and w3.1 and serratia sp. w2.3 were isolated from diseased tilapia fish in malaysia, supplied by the leading global fish supplier. proteolytic activity assays confirmed that with the exception of klebsiella sp. w4.2, al ...201222952864
eradication of pseudomonas aeruginosa biofilms by atmospheric pressure non-thermal plasma.bacteria exist, in most environments, as complex, organised communities of sessile cells embedded within a matrix of self-produced, hydrated extracellular polymeric substances known as biofilms. bacterial biofilms represent a ubiquitous and predominant cause of both chronic infections and infections associated with the use of indwelling medical devices such as catheters and prostheses. such infections typically exhibit significantly enhanced tolerance to antimicrobial, biocidal and immunological ...201222952948
fk228 from burkholderia thailandensis msmb43.fk228 [systematic name: (1s,4s,7z,10s,16e,21r)-7-ethyl-idene-4,21-di(propan-2-yl)-2-oxa-12,13-dithia-5,8,20,23-tetra-za--bicyclo[8.7.6]tricos-16-ene-3,6,9,19,22-pentone], c(24)h(36)n(4)o(6)s(2), also known as fr901228, depsipeptide, nsc 630176, romidepsin, and marketed as istodax by celgene corporation, is crystallized from ethyl acetate in p2(1) as compared to the absolute configuration of fk228, first crystallized from methanol in p2(1)2(1)2(1) [shigematsu et al. (1994 ▶). j. anti-biot.47, 311 ...201222969639
the effect of environmental conditions on biofilm formation of burkholderia pseudomallei clinical isolates.burkholderia pseudomallei, a gram-negative saprophytic bacterium, is the causative agent of the potentially fatal melioidosis disease in humans. in this study, environmental parameters including temperature, nutrient content, ph and the presence of glucose were shown to play a role in in vitro biofilm formation by 28 b. pseudomallei clinical isolates, including four isolates with large colony variants (lcvs) and small colony variants (scvs) morphotypes. enhanced biofilm formation was observed wh ...201222970167
oxygen and hydrogen peroxide in the early evolution of life on earth: in silico comparative analysis of biochemical pathways.in the universe, oxygen is the third most widespread element, while on earth it is the most abundant one. moreover, oxygen is a major constituent of all biopolymers fundamental to living organisms. besides o(2), reactive oxygen species (ros), among them hydrogen peroxide (h(2)o(2)), are also important reactants in the present aerobic metabolism. according to a widely accepted hypothesis, aerobic metabolism and many other reactions/pathways involving o(2) appeared after the evolution of oxygenic ...201222970865
multidrug-resistance and toxic metal tolerance of medically important bacteria isolated from an aquaculture system.the use of antimicrobials and toxic metals should be considered carefully in aquaculture and surrounding environments. we aimed to evaluate medically relevant bacteria in an aquaculture system and their susceptibility to antimicrobials and toxic metals. selective cultures for enterobacteria (ent), non-fermenting gram-negative rods (nfr) and gram-positive cocci (gpc) were obtained from water samples collected in two different year seasons. the isolated bacteria were biochemically identified and a ...201222972388
phylogenetically novel luxi/luxr-type quorum sensing systems isolated using a metagenomic approach.a great deal of research has been done to understand bacterial cell-to-cell signaling systems, but there is still a large gap in our current knowledge because the majority of microorganisms in natural environments do not have cultivated representatives. metagenomics is one approach to identify novel quorum sensing (qs) systems from uncultured bacteria in environmental samples. in this study, fosmid metagenomic libraries were constructed from a forest soil and an activated sludge from a coke plan ...201222983963
chromobacterium vaccinii sp. nov., isolated from native and cultivated cranberry (vaccinium macrocarpon ait.) bogs and irrigation ponds.a large number of gram-negative, motile, mesophilic, violacein-producing bacteria were isolated from the soils and roots of vaccinium macrocarpon ait. and kalmia angustifolia l. plants and from irrigation ponds associated with wild and cultivated cranberry bogs in massachusetts, usa. phylogenetic analyses of 16s rrna gene sequences placed these isolates in a clade with chromobacterium species, but the specialized environment from which they were isolated, their low genomic dna relatedness with c ...201322984138
romidepsin (fk228) combined with cisplatin stimulates dna damage-induced cell death in ovarian cancer.romidepsin (fk228) was recently approved by the fda for the treatment of cutaneous and peripheral t cell lymphoma. we have shown in vitro efficacy of fk228 in ovarian cancer. here, our goal was to evaluate fk228 combined with cisplatin in ovarian cancer in vitro and in vivo.201223010348
use of a repetitive seeding protocol to obtain diffraction-quality crystals of a putative human d-xylulokinase.in mammals, the enzyme d-xylulokinase (xk; ec 2.7.1.17) catalyses the last step of the glucuronate-xylulose pathway, in which the ketopentose sugar d-xylulose is phosphorylated to yield d-xylulose 5-phosphate (xu5p). xu5p is also a metabolite of the pentose phosphate pathway and acts as a signalling molecule that regulates lipogenesis and glycolysis in the liver. to date, no eukaryotic xk has been structurally characterized. a putative human xk was expressed in escherichia coli aided by molecula ...201223027762
rapid identification of burkholderia mallei and burkholderia pseudomallei by intact cell matrix-assisted laser desorption/ionisation mass spectrometric typing.burkholderia (b.) pseudomallei and b. mallei are genetically closely related species. b. pseudomallei causes melioidosis in humans and animals, whereas b. mallei is the causative agent of glanders in equines and rarely also in humans. both agents have been classified by the cdc as priority category b biological agents. rapid identification is crucial, because both agents are intrinsically resistant to many antibiotics. matrix-assisted laser desorption/ionisation mass spectrometry (maldi-tof ms) ...201223046611
respiratory pathogens adopt a chronic lifestyle in response to bile.chronic respiratory infections are a major cause of morbidity and mortality, most particularly in cystic fibrosis (cf) patients. the recent finding that gastro-esophageal reflux (ger) frequently occurs in cf patients led us to investigate the impact of bile on the behaviour of pseudomonas aeruginosa and other cf-associated respiratory pathogens. bile increased biofilm formation, type six secretion, and quorum sensing in p. aeruginosa, all of which are associated with the switch from acute to per ...201223049911
phenylalanine hydroxylase from legionella pneumophila is a thermostable enzyme with a major functional role in pyomelanin synthesis.legionella pneumophila is a pathogenic bacterium that can cause legionnaires' disease and other non-pneumonic infections in humans. this bacterium produces a pyomelanin pigment, a potential virulence factor with ferric reductase activity. in this work, we have investigated the role of phenylalanine hydroxylase from l. pneumophila (lppah), the product of the phha gene, in the synthesis of the pyomelanin pigment and the growth of the bacterium in defined compositions.201223049981
two structures of a thiazolinyl imine reductase from yersinia enterocolitica provide insight into catalysis and binding to the nonribosomal peptide synthetase module of hmwp1.the thiazolinyl imine reductase from yersinia enterocolitica (irp3) catalyzes the nadph-dependent reduction of a thiazoline ring in an intermediate for the formation of the siderophore yersiniabactin. two structures of irp3 were determined in the apo (1.85 å) and nadp(+)-bound (2.31 å) forms. irp3 is structurally homologous to sugar oxidoreductases such as glucose-fructose oxidoreductase and 1,5-anhydro-d-fructose reductase, as well as to biliverdin reductase. a homology model of the thiazolinyl ...201223066849
violacein induces death of resistant leukaemia cells via kinome reprogramming, endoplasmic reticulum stress and golgi apparatus collapse.it is now generally recognised that different modes of programmed cell death (pcd) are intimately linked to the cancerous process. however, the mechanism of pcd involved in cancer chemoprevention is much less clear and may be different between types of chemopreventive agents and tumour cell types involved. therefore, from a pharmacological view, it is crucial during the earlier steps of drug development to define the cellular specificity of the candidate as well as its capacity to bypass dysfunc ...201223071514
analysis of the organic hydroperoxide response of chromobacterium violaceum reveals that ohrr is a cys-based redox sensor regulated by thioredoxin.organic hydroperoxides are oxidants generated during bacterial-host interactions. here, we demonstrate that the peroxidase ohra and its negative regulator ohrr comprise a major pathway for sensing and detoxifying organic hydroperoxides in the opportunistic pathogen chromobacterium violaceum. initially, we found that an ohra mutant was hypersensitive to organic hydroperoxides and that it displayed a low efficiency for decomposing these molecules. expression of ohra and ohrr was specifically induc ...201223071722
diversity and antibiograms of bacterial organisms isolated from samples of household drinking-water consumed by hiv-positive individuals in rural settings, south africa.diarrhoea is a hallmark of hiv infections in developing countries, and many diarrhoea-causing agents are often transmitted through water. the objective of the study was to determine the diversity and antibiotic susceptibility profiles of bacterial organisms isolated from samples of household drinking-water consumed by hiv-infected and aids patients. in the present study, household water stored for use by hiv-positive patients was tested for microbial quality, and isolated bacterial organisms wer ...201223082625
chromobacterium violaceum: a potential nosocomial pathogen. 201323084472
inactivation of the transcriptional regulator-encoding gene sdia enhances rice root colonization and biofilm formation in enterobacter cloacae gs1.enterobacter cloacae gs1 is a plant growth-promoting bacterium which colonizes rice roots. in the rhizosphere environment, n-acyl homoserine lactone (nahl)-like quorum-sensing signals are known to be produced by host plants and other microbial inhabitants. e. cloacae gs1 was unable to synthesize nahl quorum-sensing signals but had the nahl-dependent transcriptional regulator-encoding gene sdia. this study was aimed at understanding the effects of sdia and nahl-dependent cross talk in rice root c ...201323086212
in vitro and in vivo antitumor activity of crude extracts obtained from brazilian chromobacterium sp isolates.natural products produced by microorganisms have been an important source of new substances and lead compounds for the pharmaceutical industry. chromobacterium violaceum is a gram-negative β-proteobacterium, abundant in water and soil in tropical and subtropical regions and it produces violacein, a pigment that has shown great pharmaceutical potential. crude extracts of five brazilian isolates of chromobacterium sp (0.25, 2.5, 25, and 250 µg/ml) were evaluated in an in vitro antitumor activity a ...201223090123
in vitro and in vivo antitumor activity of crude extracts obtained from brazilian chromobacterium sp isolates.natural products produced by microorganisms have been an important source of new substances and lead compounds for the pharmaceutical industry. chromobacterium violaceum is a gram-negative β-proteobacterium, abundant in water and soil in tropical and subtropical regions and it produces violacein, a pigment that has shown great pharmaceutical potential. crude extracts of five brazilian isolates of chromobacterium sp (0.25, 2.5, 25, and 250 µg/ml) were evaluated in an in vitro antitumor activity a ...201223090123
characterization and structure of the aquifex aeolicus protein duf752: a bacterial trna-methyltransferase (mnmc2) functioning without the usually fused oxidase domain (mnmc1).post-transcriptional modifications of the wobble uridine (u34) of trnas play a critical role in reading nna/g codons belonging to split codon boxes. in a subset of escherichia coli trna, this wobble uridine is modified to 5-methylaminomethyluridine (mnm(5)u34) through sequential enzymatic reactions. uridine 34 is first converted to 5-carboxymethylaminomethyluridine (cmnm(5)u34) by the mnme-mnmg enzyme complex. the cmnm(5)u34 is further modified to mnm(5)u by the bifunctional mnmc protein. in the ...201223091054
modulation of quorum sensing controlled behaviour of bacteria by growing seedling, seed and seedling extracts of leguminous plants.effect of growing seedling, seeds and seedlings extracts from seven leguminous plants (pisum sativum, vigna radiata, vigna mungo, cajanus cajan, lentil culinaris, cicer arietinum and trigonella foenum graecum) were screened for their ability to influence quorum sensing controlled pigment production in chromobacterium violaceum indicator strains (cv12472 and cvo26). germinating seedling and seedling extracts of only p. sativum (pea) showed inhibition of violacein production. interestingly, the t. ...201023100836
fatal chromobacterium violaceum septicemia in a south indian adult.chromobacterium violaceum is a rare human pathogen that causes potentially fatal infections especially in the tropical regions. limited awareness about this pathogen and inappropriate antibiotic therapy are some of the factors contributing to the high mortality rate. to date there have been only eight cases reported from india of which only one is an adult. to the best of our knowledge, we report here the first case of a 40-year-old man from south india with septicemic c. violaceum infection and ...201223103899
gut and root microbiota commonalities.animal guts and plant roots have absorption roles for nutrient uptake and converge in harboring large, complex, and dynamic groups of microbes that participate in degradation or modification of nutrients and other substances. gut and root bacteria regulate host gene expression, provide metabolic capabilities, essential nutrients, and protection against pathogens, and seem to share evolutionary trends.201323104406
antibiofilm activity of dendrophthoe falcata against different bacterial pathogens.dendrophthoe falcata is a hemiparasitic plant commonly used for ailments such as ulcers, asthma, impotence, paralysis, skin diseases, menstrual troubles, pulmonary tuberculosis, and wounds. in this context, the validations of the traditional claim that the leaf extract of d. falcata possesses antibiofilm and anti-quorum sensing activity against different bacterial pathogens were assessed. the bacterial biofilms were quantified by crystal violet staining. among the 17 bacterial pathogens screened ...201223115018
oxidative stress and lipid peroxidation products in cancer progression and therapy.the generation of reactive oxygen species (ros) and an altered redox status are common biochemical aspects in cancer cells. ros can react with the polyunsaturated fatty acids of lipid membranes and induce lipid peroxidation. the end products of lipid peroxidation, 4-hydroxynonenal (hne), have been considered to be a second messenger of oxidative stress. beyond ros involvement in carcinogenesis, increased ros level can inhibit tumor cell growth. indeed, in tumors in advanced stages, a further inc ...201223119185
bacterial quorum sensing: its role in virulence and possibilities for its control.quorum sensing is a process of cell-cell communication that allows bacteria to share information about cell density and adjust gene expression accordingly. this process enables bacteria to express energetically expensive processes as a collective only when the impact of those processes on the environment or on a host will be maximized. among the many traits controlled by quorum sensing is the expression of virulence factors by pathogenic bacteria. here we review the quorum-sensing circuits of st ...201223125205
metabolite profiling identified methylerythritol cyclodiphosphate efflux as a limiting step in microbial isoprenoid production.isoprenoids are natural products that are all derived from isopentenyl diphosphate (ipp) and dimethylallyl diphosphate (dmapp). these precursors are synthesized either by the mevalonate (mva) pathway or the 1-deoxy-d-xylulose 5-phosphate (dxp) pathway. metabolic engineering of microbes has enabled overproduction of various isoprenoid products from the dxp pathway including lycopene, artemisinic acid, taxadiene and levopimaradiene. to date, there is no method to accurately measure all the dxp met ...201223133596
meeting report: spontaneous lesions and diseases in wild, captive-bred, and zoo-housed nonhuman primates and in nonhuman primate species used in drug safety studies.the combination of loss of habitat, human population encroachment, and increased demand of select nonhuman primates for biomedical research has significantly affected populations. there remains a need for knowledge and expertise in understanding background findings as related to the age, source, strain, and disease status of nonhuman primates. in particular, for safety/biomedical studies, a broader understanding and documentation of lesions would help clarify background from drug-related finding ...201223135296
predation response of vibrio fischeri biofilms to bacterivorus protists.vibrio fischeri proliferates in a sessile, stable community known as a biofilm, which is one alternative survival strategy of its life cycle. although this survival strategy provides adequate protection from abiotic factors, marine biofilms are still susceptible to grazing by bacteria-consuming protozoa. subsequently, grazing pressure can be controlled by certain defense mechanisms that confer higher biofilm antipredator fitness. in the present work, we hypothesized that v. fischeri exhibits an ...201323144127
synthesis of cembranoid analogues and evaluation of their potential as quorum sensing inhibitors.natural cembranoids have shown quorum sensing inhibitory (qsi) activity, but their structure-function interactions are not well understood. thirty-four cembranoid analogues were synthesized using six natural cembranoids (1-6) previously isolated from the colombian caribbean octocorals eunicea knighti and pseudoplexaura flagellosa as lead compounds. the analogues (7-40) obtained through the selected chemical transformations were tested in vitro against the qs systems of a chromobacterium violaceu ...201323177728
structure and function of human xylulokinase, an enzyme with important roles in carbohydrate metabolism.d-xylulokinase (xk; ec 2.7.1.17) catalyzes the atp-dependent phosphorylation of d-xylulose (xu) to produce xylulose 5-phosphate (xu5p). in mammals, xk is the last enzyme in the glucuronate-xylulose pathway, active in the liver and kidneys, and is linked through its product xu5p to the pentose-phosphate pathway. xk may play an important role in metabolic disease, given that xu5p is a key regulator of glucose metabolism and lipogenesis. we have expressed the product of a putative human xk gene and ...201223179721
structure and function of human xylulokinase, an enzyme with important roles in carbohydrate metabolism.d-xylulokinase (xk; ec 2.7.1.17) catalyzes the atp-dependent phosphorylation of d-xylulose (xu) to produce xylulose 5-phosphate (xu5p). in mammals, xk is the last enzyme in the glucuronate-xylulose pathway, active in the liver and kidneys, and is linked through its product xu5p to the pentose-phosphate pathway. xk may play an important role in metabolic disease, given that xu5p is a key regulator of glucose metabolism and lipogenesis. we have expressed the product of a putative human xk gene and ...201223179721
evaluation of romidepsin for clinical activity and radioactive iodine reuptake in radioactive iodine-refractory thyroid carcinoma.historically, systemic therapy for radioactive iodine (rai)-refractory thyroid cancer has been understudied. available drugs have modest efficacy. romidepsin is a histone deacetylase inhibitor with potent antitumor effects both in vitro and in vivo. in thyroid cancer cell lines, romidepsin increases expression of both thyroglobulin and the sodium iodide symporter messenger rnas, suggesting the possibility of improved iodine concentrating ability of rai-resistant tumors.201323186033
interference in quorum sensing signal transmission amongst microbial species.antibiotics are usually studied on pure cultures of a single bacterial strain, whereas multi-species communities that inhabit human niches and the biosphere are generally ignored. the modification of quorum sensing (qs) is investigated in a system involving a co-existing signal producer and sensor bacterial cells. a pure culture of merely one bacterial species is quite rare in any niche. the interactions of different bacterial species may therefore be of special importance in pathogenicity, anti ...201223195556
nigribactin, a novel siderophore from vibrio nigripulchritudo, modulates staphylococcus aureus virulence gene expression.staphylococcus aureus is a serious human pathogen that employs a number of virulence factors as part of its pathogenesis. the purpose of the present study was to explore marine bacteria as a source of compounds that modulate virulence gene expression in s. aureus. during the global marine galathea 3 expedition, a strain collection was established comprising bacteria that express antimicrobial activity against vibrio anguillarum and/or staphylococcus aureus. within this collection we searched col ...201223203279
attenuation of pseudomonas aeruginosa virulence by marine invertebrate-derived streptomyces sp.the study aimed to discover quorum sensing (qs) inhibitors from marine sponge-derived actinomycetes and analyse its inhibitory activities against qs-mediated virulence factors in pseudomonas aeruginosa. seventy-two actinomycetes isolated from marine invertebrates collected from the western coast of india were screened against the qs indicator strain chromobacterium violaceum cv12472. methanol extracts of 12 actinomycetes showing inhibition of violacein production were accessed for downregulation ...201323210926
stage-specific expression of protease genes in the apicomplexan parasite, eimeria tenella.proteases regulate pathogenesis in apicomplexan parasites but investigations of proteases have been largely confined to the asexual stages of plasmodium falciparum and toxoplasma gondii. thus, little is known about proteases in other apicomplexa, particularly in the sexual stages. we screened the eimeria tenella genome database for proteases, classified these into families and determined their stage specific expression.201223216867
evaluation of anti-quorum sensing activity of silver nanowires.a menace of antimicrobial resistance with growing difficulties in eradicating clinical pathogens owing to the biofilm has prompted us to take up a facile aqueous-phase approach for the synthesis of silver nanowires (snws) by using ethylene glycol as a reducing agent and polyvinylpyrrolidone (pvp) as a capping agent. this synthesis is a reflux reaction seedless process. the obtained snws were about 200-250 nm in diameter and up to 3-4 μm in length. the snws were characterized by field emission sc ...201323224498
ethanolamine utilization in vibrio alginolyticus.ethanolamine is used as an energy source by phylogenetically diverse bacteria including pathogens, by the concerted action of proteins from the eut-operon. previous studies have revealed the presence of eutbc genes encoding ethanolamine-ammonia lyase, a key enzyme that breaks ethanolamine into acetaldehyde and ammonia, in about 100 bacterial genomes including members of gamma-proteobacteria. however, ethanolamine utilization has not been reported for any member of the vibrio genus. our comparati ...201223234435
bactobolin resistance is conferred by mutations in the l2 ribosomal protein.burkholderia thailandensis produces a family of polyketide-peptide molecules called bactobolins, some of which are potent antibiotics. we found that growth of b. thailandensis at 30°c versus that at 37°c resulted in increased production of bactobolins. we purified the three most abundant bactobolins and determined their activities against a battery of bacteria and mouse fibroblasts. two of the three compounds showed strong activities against both bacteria and fibroblasts. the third analog was mu ...201223249812
eugenol inhibits quorum sensing at sub-inhibitory concentrations.in bacteria, quorum sensing (qs) is a process of chemical communication involving the production, release, and subsequent detection of signaling molecules. qs regulates the production of key virulence factors in pathogens. during the screening of herbal extracts, clove extract was found to inhibit qs-controlled gene expression in pseudomonas aeruginosa qsis-lasi and chromobacterium violaceum cv026 biosensors. using a bioautographic tlc assay, preparative tlc, and hplc analysis, eugenol, the majo ...201223264268
assessing the effectiveness of functional genetic screens for the identification of bioactive metabolites.a common limitation for the identification of novel activities from functional (meta) genomic screens is the low number of active clones detected relative to the number of clones screened. here we demonstrate that constructing libraries with strains known to produce bioactives can greatly enhance the screening efficiency, by increasing the "hit-rate" and unmasking multiple activities from the same bacterial source.201223271424
assessing the effectiveness of functional genetic screens for the identification of bioactive metabolites.a common limitation for the identification of novel activities from functional (meta) genomic screens is the low number of active clones detected relative to the number of clones screened. here we demonstrate that constructing libraries with strains known to produce bioactives can greatly enhance the screening efficiency, by increasing the "hit-rate" and unmasking multiple activities from the same bacterial source.201223271424
polarization-resolved second-harmonic generation microscopy as a method to visualize protein-crystal domains.polarization-resolved second-harmonic generation (pr-shg) microscopy is described and applied to identify the presence of multiple crystallographic domains within protein-crystal conglomerates, which was confirmed by synchrotron x-ray diffraction. principal component analysis (pca) of pr-shg images resulted in principal component 2 (pc2) images with areas of contrasting negative and positive values for conglomerated crystals and pc2 images exhibiting uniformly positive or uniformly negative valu ...201223275165
polarization-resolved second-harmonic generation microscopy as a method to visualize protein-crystal domains.polarization-resolved second-harmonic generation (pr-shg) microscopy is described and applied to identify the presence of multiple crystallographic domains within protein-crystal conglomerates, which was confirmed by synchrotron x-ray diffraction. principal component analysis (pca) of pr-shg images resulted in principal component 2 (pc2) images with areas of contrasting negative and positive values for conglomerated crystals and pc2 images exhibiting uniformly positive or uniformly negative valu ...201223275165
the hydrocarbon-degrading marine bacterium cobetia sp. strain mm1ida2h-1 produces a biosurfactant that interferes with quorum sensing of fish pathogens by signal hijacking.biosurfactants are produced by hydrocarbon-degrading marine bacteria in response to the presence of water-insoluble hydrocarbons. this is believed to facilitate the uptake of hydrocarbons by bacteria. however, these diffusible amphiphilic surface-active molecules are involved in several other biological functions such as microbial competition and intra- or inter-species communication. we report the isolation and characterization of a marine bacterial strain identified as cobetia sp. mm1ida2h-1, ...201323279885
on the limitations of using ribosomal genes as references for the study of codon usage: a rebuttal.in a recent paper published in plos one, wang et al. challenge our finding that the identity of optimal codons in different genomes follows a set of clear rules. here we provide a rebuttal of their paper and demonstrate that the results of our original plos genetics paper stand. this provides us with an opportunity to bring up an aspect of how codon usage has been studied that should be of general interest. the wang et al. study, as well as many other studies, used ribosomal genes as a reference ...201223284622
dissection of quorum-sensing genes in burkholderia glumae reveals non-canonical regulation and the new regulatory gene tofm for toxoflavin production.burkholderia glumae causes bacterial panicle blight of rice and produces major virulence factors, including toxoflavin, under the control of the quorum-sensing (qs) system mediated by the luxi homolog, tofi, and the luxr homolog, tofr. in this study, a series of markerless deletion mutants of b. glumae for tofi and tofr were generated using the suicide vector system, pkksacb, for comprehensive characterization of the qs system of this pathogen. consistent with the previous studies by other resea ...201223284909
a successful antimicrobial regime for chromobacterium violaceum induced bacteremia.chromobacterium violaceum is a proteobacterium found in soil and water in tropical regions. the organism rarely causes infection in humans, yet can cause a severe systemic infection by entering the bloodstream via an open wound.201323286235
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