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promoter strength driving tetr determines the regulatory properties of tet-controlled expression systems.bacteria frequently rely on transcription repressors and activators to alter gene expression patterns in response to changes in the surrounding environment. tet repressor (tetr) is a paradigm transcription factor that senses the environmental state by binding small molecule effectors, the tetracyclines. however, recently isolated peptides that act as inducers of tetr after having been fused to the c-terminus of a carrier protein, suggest that tetr can also regulate gene expression in a signal-tr ...201222848546
zinc prevents salmonella enterica serovar typhimurium-induced loss of intestinal mucosal barrier function in broiler chickens.the study was carried out to evaluate the beneficial effects of supplemental zinc (zn) on the intestinal mucosal barrier function in salmonella enterica serovar typhimurium-challenged broiler chickens in a 42-day experiment. a total of 336 1-day-old male arbor acres broiler chicks were assigned to eight treatment groups. a 4×2 factorial arrangement of treatments was used in a completely randomized experimental design to study the effects of levels of supplemental zn (0, 40, 80 and 120 mg/kg diet ...201222834550
spi-1 encoded genes of salmonella typhimurium influence differential polarization of porcine alveolar macrophages in vitro.within the last decade, macrophages have been shown to be capable of differentiating toward a classically activated phenotype (m1) with a high antimicrobial potential or an alternatively activated phenotype (m2). some pathogens are capable of interfering with differentiation in order to down-regulate the anti-microbial activity and enhance their survival in the host.201222817641
comparative genome analysis of the high pathogenicity salmonella typhimurium strain uk-1.salmonella enterica serovar typhimurium, a gram-negative facultative rod-shaped bacterium causing salmonellosis and foodborne disease, is one of the most common isolated salmonella serovars in both developed and developing nations. several s. typhimurium genomes have been completed and many more genome-sequencing projects are underway. comparative genome analysis of the multiple strains leads to a better understanding of the evolution of s. typhimurium and its pathogenesis. s. typhimurium strain ...201222792393
diarrhea and colitis in mice require the salmonella pathogenicity island 2-encoded secretion function but not sifa or spv effectors.we investigated the roles of salmonella pathogenicity island 2 (spi-2) and two spi-2 effectors in salmonella colitis and diarrhea in genetically resistant balb/c.d2(slc11a1) congenic mice with the wild-type nramp1 locus. wild-type salmonella enterica serovar typhimurium 14028s caused a pan-colitis, and the infected mice developed frank diarrhea with a doubling of the fecal water content. an ssav mutant caused only a 26% increase in fecal water content, without producing the pathological changes ...201222778101
a whole-cell phenotypic screening platform for identifying methylerythritol phosphate pathway-selective inhibitors as novel antibacterial agents.isoprenoid biosynthesis is essential for survival of all living organisms. more than 50,000 unique isoprenoids occur naturally, with each constructed from two simple five-carbon precursors: isopentenyl diphosphate (ipp) and dimethylallyl diphosphate (dmapp). two pathways for the biosynthesis of ipp and dmapp are found in nature. humans exclusively use the mevalonate (mva) pathway, while most bacteria, including all gram-negative and many gram-positive species, use the unrelated methylerythritol ...201222777049
a salmonella typhimurium-translocated glycerophospholipid:cholesterol acyltransferase promotes virulence by binding to the rhoa protein switch regions.salmonella enterica serovar typhimurium translocates a glycerophospholipid:cholesterol acyltransferase (ssej) into the host cytosol after its entry into mammalian cells. ssej is recruited to the cytoplasmic face of the host cell phagosome membrane where it is activated upon binding the small gtpase, rhoa. ssej is regulated similarly to cognate eukaryotic effectors, as only the gtp-bound form of rhoa family members stimulates enzymatic activity. using nmr and biochemistry, this work demonstrates ...201222740689
loss of or inhibition of all multidrug resistance efflux pumps of salmonella enterica serovar typhimurium results in impaired ability to form a biofilm.to investigate the contribution of multidrug efflux pump systems of salmonella enterica serovar typhimurium to the formation of a competent biofilm.201222733653
the bimodal lifestyle of intracellular salmonella in epithelial cells: replication in the cytosol obscures defects in vacuolar replication.salmonella enterica serovar typhimurium invades and proliferates within epithelial cells. intracellular bacteria replicate within a membrane bound vacuole known as the salmonella containing vacuole. however, this bacterium can also replicate efficiently in the cytosol of epithelial cells and net intracellular growth is a product of both vacuolar and cytosolic replication. here we have used semi-quantitative single-cell analyses to investigate the contribution of each of these replicative niches ...201222719929
human milk mucin 1 and mucin 4 inhibit salmonella enterica serovar typhimurium invasion of human intestinal epithelial cells in vitro.many human milk glycans inhibit pathogen binding to host receptors and their consumption by infants is associated with reduced risk of disease. salmonella infection is more frequent among infants than among the general population, but the incidence is lower in breast-fed babies, suggesting that human milk could contain components that inhibit salmonella. this study aimed to test whether human milk per se inhibits salmonella invasion of human intestinal epithelial cells in vitro and, if so, to id ...201222718031
a previously uncharacterized gene stm0551 plays a repressive role in the regulation of type 1 fimbriae in salmonella enterica serotype typhimurium.salmonella enterica serotype typhimurium produces surface-associated fimbriae that facilitate adherence of the bacteria to a variety of cells and tissues. type 1 fimbriae with binding specificity to mannose residues are the most commonly found fimbrial type. in vitro, static-broth culture favors the growth of s. typhimurium with type 1 fimbriae, whereas non-type 1 fimbriate bacteria are obtained by culture on solid-agar media. previous studies demonstrated that the phenotypic expression of type ...201222716649
the importance of motility and chemotaxis for extra-animal survival of salmonella enterica serovar typhimurium and dublin.this study investigated the importance of flagella and motility of salmonella enterica serovar typhimurium and dublin in models of extra-animal survival.201222716502
analyzing cellular internalization of nanoparticles and bacteria by multi-spectral imaging flow cytometry.nanoparticulate systems have emerged as valuable tools in vaccine delivery through their ability to efficiently deliver cargo, including proteins, to antigen presenting cells. internalization of nanoparticles (np) by antigen presenting cells is a critical step in generating an effective immune response to the encapsulated antigen. to determine how changes in nanoparticle formulation impact function, we sought to develop a high throughput, quantitative experimental protocol that was compatible wi ...201222710268
expression and delivery of tetanus toxin fragment c fused to the n-terminal domain of sipb enhances specific immune responses in mice.live attenuated bacteria can be used as a carrier for the delivery of foreign antigens to a host's immune system. the n-terminal domain of sipb, a translocon protein of the type iii secretion system of salmonella enterica serovar typhimurium, is required for secretion and outer membrane localization. in the present study, vaccine plasmids for antigen delivery in which the non-toxic tetanus toxin fragment c (ttfc), which contains a t cell epitope, is fused to the n-terminal 160 amino acids of sip ...201222708880
slc11a1 (nramp1) impairs growth of salmonella enterica serovar typhimurium in macrophages via stimulation of lipocalin-2 expression.the expression of the cation transporter nramp1 (slc11a1) in late phagolysosomes confers resistance to infection with several intracellular pathogens, such as salmonella enterica, in mice. the antimicrobial actions of nramp1 are attributable, in part, to modulation of macrophage immune function and cellular iron metabolism--the latter affecting the availability of the essential nutrient iron for intraphagosomal bacteria. here, we provide novel evidence that nramp1 functionality increases the exp ...201222706314
mechanisms used by virulent salmonella to impair dendritic cell function and evade adaptive immunity.innate and adaptive immunity are inter-related by dendritic cells (dcs), which directly recognize bacteria through the binding of pathogen-associated molecular patterns (pamps) to specialized receptors on their surface. after capturing and degrading bacteria, dcs present their antigens as small peptides bound to mhc molecules and prime naive bacteria-specific t cells. in response to pamp recognition dcs undergo maturation, which is a phenotypic change that increases their immunogenicity and prom ...201222703384
effect of iacp mutation on flagellar phase variation in salmonella enterica serovar typhimurium strain uk-1.flagella are surface appendages that are important for bacterial motility and invasion of host cells. two flagellin subunits in salmonella enterica serovar typhimurium, flic and fljb, are alternatively expressed by a site-specific dna inversion mechanism called flagellar phase variation. although this inversion mechanism is understood at the molecular level, the key factor controlling the expression of the two flagellin subunits has not been determined. in this study, we found that a putative ac ...201222685287
cysteine catabolism and cysteine desulfhydrase (cdsh/stm0458) in salmonella enterica serovar typhimurium.cysteine is potentially toxic and can affect diverse functions such as oxidative stress, antibiotic resistance, and swarming motility. the contribution of cysteine catabolism in modulating responses to cysteine has not been examined, in part because the genes have not been identified and mutants lacking these genes have not been isolated or characterized. we identified the gene for a previously described cysteine desulfhydrase, which we designated cdsh (formerly stm0458). we also identified a di ...201222685283
baer protein from salmonella enterica serovar paratyphi a induces inflammatory response in murine and human cell lines.baer is the response regulator of the two-component system, baesr, found in escherichia coli (e. coli) and salmonella. several biological functions of baer, related to multidrug efflux and bacterial virulence, have been described. herein, we report a putative function of baer during inflammatory response of the host by using baer protein of salmonella enterica paratyphi a (s. paratyphi a) origin overexpressed in e. coli, and raw 264.7 and thp-1 cells as in vitro models. baer (3 μg/ml) upregulate ...201324055826
design of a core-shell type immuno-magnetic separation system and multiplex pcr for rapid detection of pathogens from food samples.we report an immuno-magnetic separation system developed by the immobilization of pathogen-specific antibodies on the core-shell magnetic beads. the magnetic beads were grafted with glycidylmethacrylate (gma) using surface-initiated atom transfer radical polymerization (si-atrp). for immuno-magnetic separation (ims) of target bacterial cells from others, antibodies for escherichia coli and salmonella enterica serovar typhimurium cells were immobilized on the magnetic beads via glutaraldehyde cou ...201324048640
the prevalence of swine enteropathogens in brazilian grower and finish herds.diarrhoea among growing and finishing pigs is an important problem in many herds. the prevalence of l. intracellularis, b. pilosicoli, b. hyodysenteriae, salmonella spp., enterotoxigenic e. coli, trichuris suis and the occurrence of mixed infection were investigated. fecal samples for forty-six herds with diarrhea or a history of diarrhea were randomly collected in minas gerais state, brazil. the enteric pathogens were detected by culture (e. coli and salmonella sp.), pcr (l. intracellularis and ...201324159297
complete nucleotide sequences of virulence-resistance plasmids carried by emerging multidrug-resistant salmonella enterica serovar typhimurium isolated from cattle in hokkaido, japan.in the present study, we have shown that virulence-resistance plasmids from emerging multidrug-resistant isolates of salmonella enterica serovar typhimurium were derived from a virulence-associated plasmid, essential for systematic invasiveness of s. typhimurium in mice (pslt), through acquisition of a large insert containing a resistance island flanked by is1294 elements. a bla cmy-2-carrying plasmid from a cefotaxime-resistant isolate comprised a segment of escherichia coli plasmid par060302 a ...201324155970
multiple interfaces between a serine recombinase and an enhancer control site-specific dna inversion.serine recombinases are often tightly controlled by elaborate, topologically-defined, nucleoprotein complexes. hin is a member of the dna invertase subclass of serine recombinases that are regulated by a remote recombinational enhancer element containing two binding sites for the protein fis. two hin dimers bound to specific recombination sites associate with the fis-bound enhancer by dna looping where they are remodeled into a synaptic tetramer competent for dna chemistry and exchange. here we ...201324151546
synthesis and characterization of nano-encapsulated black pepper oleoresin using hydroxypropyl beta-cyclodextrin for antioxidant and antimicrobial applications.previous studies have reported antimicrobial and antioxidant activity of black pepper oleoresin which is associated to its phenolic compounds and piperine. the ability of cyclodextrins to form an inclusion complex with a guest molecule could improve black pepper oleoresin application, bioavailability, and stability in foods. hydroxypropyl beta-cyclodextrin (hpbcd) inclusion complex with black pepper olereosin were synthesized using the kneading method and characterized for its physico-chemical p ...201324329956
combining de novo and reference-guided assembly with scaffold_builder.genome sequencing has become routine, however genome assembly still remains a challenge despite the computational advances in the last decade. in particular, the abundance of repeat elements in genomes makes it difficult to assemble them into a single complete sequence. identical repeats shorter than the average read length can generally be assembled without issue. however, longer repeats such as ribosomal rna operons cannot be accurately assembled using existing tools. the application scaffold_ ...201324267787
bioprotection of ready-to-eat probiotic artichokes processed with lactobacillus paracasei lmgp22043 against foodborne pathogens.the survival of 3 pathogens listeria monocytogenes atcc19115, salmonella enterica subsp. enterica atcc13311, and escherichia coli atcc8739 was evaluated over time in ready-to-eat (rte) artichoke products processed or not with the probiotic strain lactobacillus paracasei lmgp22043. both probiotic and standard products (final ph about 4.0; aw = 0.98) dressed with oil and packaged in modified atmosphere were inoculated with pathogens at a level of about 3 log cfu/g and stored at 4 ºc for 45 d. path ...201324245894
a non-classical assembly pathway of escherichia coli pore-forming toxin cytolysin a.cytolysin a (clya) is an α-pore forming toxin from pathogenic escherichia coli (e. coli) and salmonella enterica. here, we report that e. coli clya assembles into an oligomeric structure in solution in the absence of either bilayer membranes or detergents at physiological temperature. these oligomers can rearrange to create transmembrane pores when in contact with detergents or biological membranes. intrinsic fluorescence measurements revealed that oligomers adopted an intermediate state found d ...201324019520
differences in biofilm formation of produce and poultry salmonella enterica isolates and their persistence on spinach plants.spinach plants were irrigated biweekly with water containing 2.1 log cfu salmonella/100 ml water (the maximum escherichia coli mpn recommended by the leafy greens marketing agreement; lgma), or 4.1 cfu salmonella/100 ml water to determine salmonella persistence on spinach leaves. green fluorescent protein expressing salmonella were undetectable by most-probable number (mpn) at 24 h and 7 days following each irrigation event. this study indicates that salmonella are unlikely to persist on spinach ...201324010621
unique n-terminal arm of mycobacterium tuberculosis phop protein plays an unusual role in its regulatory function.mycobacterium tuberculosis phop, a master regulator involved in complex lipid biosynthesis and expression of unknown virulence determinants, is composed of an n-terminal receiver domain and a c-terminal effector domain. the two experimentally characterized phop orthologs, from escherichia coli and salmonella enterica, display vastly different regulatory capabilities. here, we demonstrate that the 20-residue-long n-terminal arm unique to m. tuberculosis phop plays an essential role in the expande ...201323963455
transmission of an oxygen availability signal at the salmonella enterica serovar typhimurium fis promoter.the nucleoid-associated protein fis is a global regulator of gene expression and chromosome structure in escherichia coli and salmonella enterica. despite the importance of fis for infection and intracellular invasion, very little is known about the regulation of s. enterica fis expression. under standard laboratory growth conditions, fis is highly expressed during rapid growth but is then silenced as growth slows. however, if cells are cultured in non-aerated conditions, fis expression is susta ...201324358360
assessment of pathogenic bacteria in treated graywater and irrigated soils.reuse of graywater (gw) for irrigation is recognized as a sustainable solution for water conservation. one major impediment for reuse of gw is the possible presence of pathogenic microorganisms. the presence and abundance of six pathogens and indicators were investigated in three gw recirculating vertical flow constructed wetland treatment systems and their respective irrigated yard soils. the treated gw and soils were monitored once every two months for six months using real-time quantitative p ...201323666359
screening for polyphenols, antioxidant and antimicrobial activitiesof extracts from eleven helianthemum taxa (cistaceae) used in folk medicine in south-eastern spain.the helianthemum genus contains approximately one hundred taxa. some of them are important medicinal plants used in several countries for many different purposes. however, studies addressing the phytochemistry of many of these species or their biological activities are currently nonexistent.201323615124
cd137 expressed on neutrophils plays dual roles in antibacterial responses against gram-positive and gram-negative bacterial infections.severe sepsis and septic shock caused mainly by bacterial infections are life-threatening conditions that urge the development of novel therapies. however, host responses to and pathophysiology of sepsis have not been clearly understood, which remains a major obstacle for the development of effective therapeutics. recently, we have shown that stimulation of a costimulatory molecule, cd137, enhanced survival of mice infected with the gram-positive (g(+)) intracellular bacterium listeria monocytog ...201323545301
enterococcus faecalis subverts and invades the host urothelium in patients with chronic urinary tract infection.bacterial urinary tract infections (uti) are a major growing concern worldwide. uropathogenic escherichia coli has been shown to invade the urothelium during acute uti in mice and humans, forming intracellular reservoirs that can evade antibiotics and the immune response, allowing recurrence at a later date. other bacterial species, such as staphylococcus saprophyticus, klebsiella pneumonia and salmonella enterica have also been shown to be invasive in acute uti. however, the role of intracellul ...201324363814
physiological and functional characteristics of propionibacterium strains of the poultry microbiota and relevance for the development of probiotic products.the prevention and control of pathogens colonization through probiotics administration in poultry feeding is of increasing interest. the genus propionibacterium is an attractive candidate for the development of probiotic cultures as they produce short chain fatty acids (scfa) by carbohydrates fermentation. the presence of strains of this genus in hens of conventional production systems and backyard hens was investigated. propionibacteria were isolated from the intestine and identified by physiol ...201323973927
use of bioluminescence mutant screening for identification of edwardsiella ictaluri genes involved in channel catfish (ictalurus punctatus) skin colonization.initial invasion of the host is the first and vital part of any infection process. we have demonstrated that edwardsiella ictaluri is capable of colonizing and penetrating catfish skin. therefore, a mutant library was constructed by random insertion of the mar2xt7 transposon into the chromosome of e. ictaluri harboring the bioluminescence plasmid pakgfplux1. this library was then screened through a series of three consecutive challenges for mutants showing a decreased ability to colonize the cat ...201323092811
intranasal vaccination in mice with an attenuated salmonella enterica serovar 908htr a expressing cp15 of cryptosporidium: impact of malnutrition with preservation of cytokine secretion.cryptosporidium is a protozoan parasite associated with acute and persistent diarrhea that, even in asymptomatic persons, can impair normal growth and potentially cognitive and physical development in young children. the recent availability of the complete gene sequence for cryptosporidium hominis antigen cp15 allows examination of innovative vaccine regimens involving intra-nasal antigen priming with live bacterial vectors applicable to human populations. we used a recently described weaned mou ...201323246541
internalisation potential of escherichia coli o157:h7, listeria monocytogenes, salmonella enterica subsp. enterica serovar typhimurium and staphylococcus aureus in lettuce seedlings and mature plants.the internalisation potential of listeria monocytogenes, staphylococcus aureus, escherichia coli o157:h7 and salmonella enterica subsp. enterica serovar typhimurium in lettuce was evaluated using seedlings grown in vermiculite in seedling trays as well as hydroponically grown lettuce. sterile distilled water was spiked with one of the four human pathogenic bacteria (10(5) cfu/ml) and used to irrigate the plants. the potential for pathogen internalisation was investigated over time using light mi ...201323708570
new decontamination method based on caprylic acid in combination with citric acid or vanillin for eliminating cronobacter sakazakii and salmonella enterica serovar typhimurium in reconstituted infant formula.the antimicrobial effects of natural compounds (caprylic acid, ca; citric acid, cta; and vanillin, vnl) on the inactivation of cronobacter sakazakii and salmonella enterica serovar typhimurium were examined in reconstituted infant formula. the samples were treated with: 1) ca, cta, or vnl alone (0, 10, 20, 30, 40, 60, and 80 mm); 2) a combination of ca (10 and 20 mm) and cta (15 and 30 mm); and 3) a combination of ca (10 and 20 mm) and vnl (15 and 30 mm), at mild feeding temperatures (40 °c and ...201324042002
the pathogen-annotated tracking resource network (patrn) system: a web-based resource to aid food safety, regulatory science, and investigations of foodborne pathogens and disease.investigation of foodborne diseases requires the capture and analysis of time-sensitive information on microbial pathogens that is derived from multiple analytical methods and sources. the web-based pathogen-annotated tracking resource network (patrn) system (www.patrn.net) was developed to address the data aggregation, analysis, and communication needs important to the global food safety community for the investigation of foodborne disease. patrn incorporates a standard vocabulary for describin ...201323541197
several enteropathogens are circulating in suckling and newly weaned piglets suffering from diarrhea in the province of villa clara, cuba.intestinal contents of suckling (n = 45) and newly weaned (n = 45) piglets, suffering from diarrhea in the province of villa clara in cuba, were tested for viral, bacterial, and parasitic enteropathogens from may to june 2008. at least one enteropathogen was identified in 53.3 % of piglets and enterotoxigenic escherichia coli (etec; 25.6 %) was the major pathogen; mostly sta(+)/stb(+) or f4(+)/sta(+)/stb(+) etec were isolated. the overall occurrence of the rest of pathogens was 10 % for transmis ...201322843242
development and application of a multiplex pcr assay for rapid detection of 4 major bacterial pathogens in ducks.infections with pasteurella multocida, salmonella enterica, riemerella anatipestifer, and escherichia coli result in high morbidity and mortality, which cause significant economic loss in the poultry industry. it can be difficult to distinguish these pathogens based on clinical signs because these pathogens can cause similar clinical signs and coinfections can occur. thus, rapid and sensitive detection of these 4 major bacterial pathogens are important in ducks. the aim of this study was to deve ...201323571324
the art of blocking adp-ribosyltransferases (arts): nanobodies as experimental and therapeutic tools to block mammalian and toxin arts.in 1901, the first nobel prize in physiology or medicine was awarded to emil von behring for his ground-breaking discovery of serum therapy: serum from horses vaccinated with toxin-containing culture medium of corynebacterium diphtheriae contained life-saving 'antitoxins'. the molecular nature of the adp-ribosylating toxin and the neutralizing antibodies were unraveled only 50 years later. today, von behring's antibody therapy is being refined with a new generation of recombinant antibodies and ...201323627412
toll-like receptor 5-dependent immunogenicity and protective efficacy of a recombinant fusion protein vaccine containing the nontoxic domains of clostridium difficile toxins a and b and salmonella enterica serovar typhimurium flagellin in a mouse model of clostridium difficile disease.clostridium difficile is a spore-forming bacillus that produces toxin-mediated enteric disease. c. difficile expresses two major virulence factors, toxin a (tcda) and toxin b (tcdb). human and animal studies demonstrate a clear association between humoral immunity to these toxins and protection against c. difficile infection (cdi). the receptor binding-domains (rbds) of tcda and tcdb are known to be immunogenic. here, we tested the immunoadjuvant properties of salmonella enterica serovar typhimu ...201323545305
increased susceptibility of melanin-concentrating hormone-deficient mice to infection with salmonella enterica serovar typhimurium.melanin-concentrating hormone (mch) was initially identified in mammals as a hypothalamic neuropeptide regulating appetite and energy balance. however, the wide distribution of mch receptors in peripheral tissues suggests additional functions for mch which remain largely unknown. we have previously reported that mice lacking mch develop attenuated intestinal inflammation when exposed to clostridium difficile toxin a. to further characterize the role of mch in host defense mechanisms against inte ...201323115043
a new plant-derived antibacterial is an inhibitor of efflux pumps in staphylococcus aureus.an in-depth evaluation was undertaken of a new antibacterial natural product (1) recently isolated and characterised from the plant hypericum olympicum l. cf. uniflorum. minimum inhibitory concentrations (mics) were determined for a panel of bacteria, including: meticillin-resistant and -susceptible strains of staphylococcus aureus, staphylococcus epidermidis and staphylococcus haemolyticus; vancomycin-resistant and -susceptible enterococcus faecalis and enterococcus faecium; penicillin-resistan ...201324119569
a culture-independent sequence-based metagenomics approach to the investigation of an outbreak of shiga-toxigenic escherichia coli o104:h4.identification of the bacterium responsible for an outbreak can aid in disease management. however, traditional culture-based diagnosis can be difficult, particularly if no specific diagnostic test is available for an outbreak strain.201323571589
high incidence of campylobacter concisus in gastroenteritis in north jutland, denmark: a population-based study.the incidence of non-thermophilic campylobacter species was assessed in an unselected population-based study in a mixed urban and rural community in north jutland, denmark. in a 2-year study period, 11,314 faecal samples from 8302 patients with gastroenteritis were cultured with supplement of the filter method. we recovered a high incidence of campylobacter concisus (annual incidence 35/100,000 inhabitants), almost as high as the common campylobacter jejuni/coli. in contrast, there was a very lo ...201322512739
the in vivo extracellular life of facultative intracellular bacterial parasites: role in pathogenesis.classically labeled facultative intracellular pathogens are characterized by the ability to have an intracellular phase in the host, which is required for pathogenicity, while capable of extracellular growth in vitro. the ability of these bacteria to replicate in cell-free conditions is usually assessed by culture in artificial bacteriological media. however, the extracellular growth ability of these pathogens may also be expressed by a phase of extracellular infection in the natural setting of ...201322795971
characterization of five novel endolysins from gram-negative infecting bacteriophages.we here characterize five globular endolysins, encoded by a set of gram-negative infecting bacteriophages: bcepc6gp22 (burkholderia cepacia phage bcepc6b), p2gp09 (escherichia coli phage p2), psp3gp10 (salmonella enterica phage psp3), k11gp3.5 and kp32gp15 (klebsiella pneumoniae phages k11 and kp32, respectively). in silico, bcepc6gp22, p2gp10 and psp3gp10 are predicted to possess lytic transglycosylase activity, whereas k11gp3.5 and kp32gp15 have putative amidase activity. all five endolysins s ...201322832988
antibacterial activity and mode of action of a commercial citrus fruit extract.this study addresses the antibacterial activity and mechanism of action of bioll(+®), a commercial extract obtained from citrus fruits.201323581704
occurrence of pathogens in wild rodents caught on swedish pig and chicken farms.a total of 207 wild rodents were caught on nine pig farms, five chicken farms and five non-farm locations in sweden and surveyed for a selection of bacteria, parasites and viruses. lawsonia intracellularia and pathogenic yersinia enterocolitica were only detected in rodents on pig farms (9% and 8% prevalence, respectively) which indicate that these agents are more likely to be transmitted to rodents from pigs or the environment on infected farms. brachyspira hyodysenteriae (1%), brachyspira inte ...201323174339
cell-free culture supernatant of bifidobacterium breve cncm i-4035 decreases pro-inflammatory cytokines in human dendritic cells challenged with salmonella typhi through tlr activation.dendritic cells (dcs) constitute the first point of contact between gut commensals and our immune system. despite growing evidence of the immunomodulatory effects of probiotics, the interactions between the cells of the intestinal immune system and bacteria remain largely unknown. indeed,, the aim of this work was to determine whether the probiotic bifidobacterium breve cncm i-4035 and its cell-free culture supernatant (cfs) have immunomodulatory effects in human intestinal-like dendritic cells ...201323555025
impact of 6 different intestinal bacteria on broiler breeder sperm motility in vitro.male fertility is often evaluated by measuring sperm parameters, including concentration, viability, and motility. this is important because after copulation occurs, sperm must overcome many barriers in the female reproductive tract to fertilize the ovum. in mammalian species, sperm have been shown to have reduced motility when bacteria are present. in male broiler breeders, bacteria have been associated with spermatozoa, but their effect on motility has not been investigated. the sperm quality ...201323873566
growth-inhibiting and morphostructural effects of constituents identified in asarum heterotropoides root on human intestinal bacteria.the growth-inhibiting and morphostructural effects of seven constituents identified in asarum heterotropoides root on 14 intestinal bacteria were compared with those of the fluoroquinolone antibiotic ciprofloxacin.201324083511
microbiota-liberated host sugars facilitate post-antibiotic expansion of enteric pathogens.the human intestine, colonized by a dense community of resident microbes, is a frequent target of bacterial pathogens. undisturbed, this intestinal microbiota provides protection from bacterial infections. conversely, disruption of the microbiota with oral antibiotics often precedes the emergence of several enteric pathogens. how pathogens capitalize upon the failure of microbiota-afforded protection is largely unknown. here we show that two antibiotic-associated pathogens, salmonella enterica s ...201323995682
synthesis, characterization, and antimicrobial properties of copper nanoparticles.copper nanoparticle synthesis has been gaining attention due to its availability. however, factors such as agglomeration and rapid oxidation have made it a difficult research area. in the present work, pure copper nanoparticles were prepared in the presence of a chitosan stabilizer through chemical means. the purity of the nanoparticles was authenticated using different characterization techniques, including ultraviolet visible spectroscopy, transmission electron microscopy, x-ray diffraction, f ...201324293998
comparison of 3m petrifilm aerobic count plates to standard plating methodology for use with aoac antimicrobial efficacy methods 955.14, 955.15, 964.02, and 966.04 as an alternative enumeration procedure: collaborative study.a multilaboratory study was conducted to determine the equivalence of the 3m petrifilm aerobic count plate and standard plating methodology for measuring viable bacteria and spores recovered from hard-surface carriers (stainless steel and porcelain), also known as "control carrier counts," used in aoac antimicrobial efficacy test methods. six laboratories participated in the study in which carriers inoculated with staphylococcus aureus, pseudomonas aeruginosa, salmonella enterica, and spores of ...201324000742
conducting nanosponge electroporation for affordable and high-efficiency disinfection of bacteria and viruses in water.high-efficiency, affordable, and low energy water disinfection methods are in great need to prevent diarrheal illness, which is one of the top five leading causes of death over the world. traditional water disinfection methods have drawbacks including carcinogenic disinfection byproducts formation, energy and time intensiveness, and pathogen recovery. here, we report an innovative method that achieves high-efficiency water disinfection by introducing nanomaterial-assisted electroporation impleme ...201323987737
cgmolluscidin, a novel dibasic residue repeat rich antimicrobial peptide, purified from the gill of the pacific oyster, crassostrea gigas.a 5.5 kda antimicrobial peptide consisting of 55 amino acids, cgmolluscidin, was purified from the acidified gill extract of the pacific oyster, crassostrea gigas, by ion-exchange and c18 reversed-phase high performance liquid chromatography. by comparing the n-terminal amino acid sequences and the molecular weight of this peptide with those of other known antimicrobial peptides, it has been revealed that this peptide had no homology with any known peptides. cgmolluscidin showed potent antimicro ...201323711469
the acetylproteome of gram-positive model bacterium bacillus subtilis.n(ε) -lysine acetylation, a reversible and highly regulated ptm, has been shown to occur in the model gram-negative bacteria escherichia coli and salmonella enterica. here, we extend this acetylproteome analysis to bacillus subtilis, a model gram-positive bacterium. through anti-acetyllysine antibody-based immunoseparation of acetylpeptides followed by nano-hplc/ms/ms analysis, we identified 332 unique lysine-acetylated sites on 185 proteins. these proteins are mainly involved in cellular housek ...201323468065
evaluation antibacterial activity of quaternary-based chitin/chitosan derivatives in vitro.total of 3 water-soluble quaternary-based chitin/chitosan derivatives, which have an identical molecular weight and anion, were synthesized and characterized. their antibacterial activities against salmonella cholerae-suis and bacillus subtilis were evaluated in vitro. the polysaccharides exhibited the antibacterial efficiency. their minimum inhibitory concentration (mic) values vary from 0.02 to 20.48 mg/ml, and their minimum bactericidal concentration (mbc) values vary from 0.08 to 40.96 mg/ml ...201323301607
bioengineered 2'-fucosyllactose and 3-fucosyllactose inhibit the adhesion of pseudomonas aeruginosa and enteric pathogens to human intestinal and respiratory cell lines.human milk oligosaccharides help to prevent infectious diseases in breastfed infants. larger scale testing, particularly in animal models and human clinical studies, is still limited due to shortened availability of more complex oligosaccharides. the purpose of this study was to evaluate 2'-fucosyllactose (2'-fl) and 3-fucosyllactose (3-fl) synthesized by whole-cell biocatalysis for their biological activity in vitro. therefore, we have tested these oligosaccharides for their inhibitory potentia ...201324074741
development of a magnetic nanoparticles microarray for simultaneous and simple detection of foodborne pathogens.foodborne diseases are a widespread and growing public health problem affecting both developed and developing countries, microbiologically contaminated food and water are the major causes of diarrhoeal diseases. methods based on polymerase chain reaction (pcr) and microarrays are rapid and sensitive enough to detect very small quantities of microorganisms, however, the requirement for expensive equipments limits their application. in the present paper, we describe a method based on multiplex pcr ...201323909141
short communication: survey of animal-borne pathogens in the farm environment of 13 dairy operations.a survey was conducted on 13 dairies to determine the occurrence of 5 animal-borne pathogens (salmonella enterica, escherichia coli o157:h7, campylobacter jejuni, mycobacterium avium ssp. paratuberculosis, and cryptosporidium parvum) and their distributions across farm elements (feces, bedding, milk filters, stored manure, field soil, and stream water). presence of c. parvum was measured only in feces and stored manure. all but one farm were positive for at least one pathogen species, and 5 farm ...201323810596
a dna microarray for the versatile diagnosis of infectious diarrhea.several bacteria, viruses, and parasites cause diarrhea as coinfecting pathogens. we designed a dna microarray comprising 60-bp probes spotted 194 times for the multiplex detection of 33 enteropathogenic bacteria and seven enteropathogenic viruses, and the archaeon methanobrevibacter smithii was used as an internal positive control. nine pathogen-free stool specimens were used as negative controls. one of these control specimens was further spiked with salmonella enterica as a positive control. ...201323758523
lateral transfer, vertical translocation, and survival of inoculated bacteria during moisture enhancement of pork.lateral transfer, vertical translocation, and survival of bacteria during moisture enhancement of pork were investigated under laboratory conditions. in the first experiment, a pork loin was surface inoculated with escherichia coli biotype i and moisture enhanced with brine to 10%. after the inoculated loin had been injected, four uninoculated loins were processed in the same manner, without cleaning or sanitizing the injector equipment. samples were collected from both the surface and the inter ...201323575120
increased detection of invasive enteropathogenic bacteria in pre-incubated blood culture materials by real-time pcr in comparison with automated incubation in sub-saharan africa.invasive enteropathogenic bacteria can cause systemic infections. data from studies with pcr detection suggest, at least for salmonella enterica, that blood culture may lead to underestimation in the tropics. corresponding data are lacking for other invasive enteropathogenic bacteria. we compared classical blood culture and molecular methods for the diagnosis of blood infections.201323547567
zoonotic fecal pathogens and antimicrobial resistance in county fair animals.livestock fairs present a unique opportunity for the public to experience close contact with animals, but may also expose people to zoonotic pathogens through contact with animal feces. the goal of this study was to screen cattle, sheep, goat, chicken, rabbit and horse feces from a livestock fair in california for the potentially zoonotic pathogens escherichia coli o157:h7, salmonella, campylobacter, vibrio, cryptosporidium and giardia spp., as well as determining the level of antimicrobial resi ...201323260373
prevalence and characterization of foodborne pathogens in dairy cattle in the eastern part of japan.to investigate the prevalence and characterization of foodborne pathogens [campylobacter spp., shiga toxin-producing escherichia coli (stec), listeria monocytogenes and salmonella spp.] in dairy cows, rectal content grab samples were collected from 250 dairy cows reared on 25 dairy farms in eastern japan from december 2010 through february 2011. campylobacter jejuni was isolated from 106 (42%) cows on 23 (92%) farms, stec o157 from three cows on one farm, l. monocytogenes from three cows on anot ...201323208291
engineering, conjugation, and immunogenicity assessment of escherichia coli o121 o antigen for its potential use as a typhoid vaccine component.state-of-the-art production technologies for conjugate vaccines are complex, multi-step processes. an alternative approach to produce glycoconjugates is based on the bacterial n-linked protein glycosylation system first described in campylobacter jejuni. the c. jejuni n-glycosylation system has been successfully transferred into escherichia coli, enabling in vivo production of customized recombinant glycoproteins. however, some antigenic bacterial cell surface polysaccharides, like the vi antige ...201323053636
cervical abscesses due to co-infection with burkholderia pseudomallei, salmonella enterica serovar stanley and mycobacterium tuberculosis in a patient with diabetes mellitus.infections due to mycobacterium tuberculosis, burkholderia pseudomallei and non-typhoidal salmonella cause significant morbidity and mortality throughout the world. these intracellular pathogens share some common predisposing factors and clinical features. co-infection with two of these organisms has been reported previously but, to our knowledge, this is the first time that infection with all three has been reported in one person.201324209898
analysis of bacterial diversity during the fermentation of inyu, a high-temperature fermented soy sauce, using nested pcr-denaturing gradient gel electrophoresis and the plate count method.the diversity of bacteria associated with the fermentation of inyu, also known as black soy sauce, was studied through the nested pcr-denaturing gradient gel electrophoresis (dgge) of samples collected from the fermentation stages of the inyu production process. the dgge profiles targeted the bacterial 16s rdna and revealed the presence of citrobacter farmeri, enterobacter cloacae, enterobacter hormaechei, enterococcus faecium, klebsiella pneumoniae, pantoea agglomerans, salmonella enterica, ser ...201323200659
characterization of aminoglycoside-modifying enzymes in enterobacteriaceae clinical strains and characterization of the plasmids implicated in their diffusion.a total of 788 clinical enterobacteriaceae were collected to describe the aminoglycoside-modifying genes (ame genes) and to characterize the plasmids that carry these genes. among the 788 strains collected, 330 (41.8%) were aminoglycoside-resistant: 264 escherichia coli (80%), 33 proteus mirabilis (10%), 10 klebsiella pneumoniae (3%), six k. oxytoca (1.8%), five enterobacter cloacae (1.5%), three morganella morganii (0.9%), three providencia stuartii (0.9%), two salmonella enterica (0.6%), and o ...201323206280
food-borne zoonotic pathogens and antimicrobial resistance of indicator bacteria in urban wild boars in barcelona, spain.wildlife is increasingly abundant in urban environments, but little is known about the zoonotic pathogens carried by these populations. urban wild boars are of particular concern because this species is well-known as a pathogen reservoir, and thus, we studied selected zoonotic pathogens in urban wild boars in barcelona, spain (n=41). salmonella enterica was found in 5.00% (95% ci 0.61-16.91) and campylobacter coli in 4.88% (95% ci 0.6-16.53) of the animals. e. coli o157:h7 and c. jejuni were not ...201323992794
cell-free supernatants obtained from fermentation of cheese whey hydrolyzates and phenylpyruvic acid by lactobacillus plantarum as a source of antimicrobial compounds, bacteriocins, and natural aromas.cheese whey hydrolyzates supplemented with phenylpyruvic acid (ppa) and commercial nutrients can be efficiently metabolized by lactobacillus plantarum cect-221 to biosynthesize some compounds with attractive applications in the food market. the main metabolites of cell-free extracts were antimicrobial compounds such as phenyllactic acid (pla) and lactic acid (la). the production of pla by l. plantarum cect-221 was evaluated in the man-rogosa-sharpe broth supplemented with two biosynthetic precur ...201323934083
effect of the temperature of the dipping solution on the antimicrobial effectiveness of various chemical decontaminants against pathogenic and spoilage bacteria on poultry.the influence of the temperature of the dipping solution on the antimicrobial effectiveness of several chemical poultry decontaminants was assessed. a total of 765 poultry legs were inoculated with gram-positive bacteria (listeria monocytogenes, staphylococcus aureus, bacillus cereus, or brochothrix thermosphacta) or gram-negative bacteria (salmonella enterica serotype enteritidis, escherichia coli, yersinia enterocolitica, or pseudomonas fluorescens). samples were dipped for 15 min in solutions ...201323643125
in vitro assessment of functional properties of lactic acid bacteria isolated from faecal microbiota of healthy dogs for potential use as probiotics.lactic acid bacteria were isolated and identified in the faeces of chinese crested and yorkshire terrier pups and their probiotic features were investigated in vitro. thirty seven isolates were identified as lactobacillus or enterococcus. out of these isolates, 31 were lactic acid bacteria (lab) and belonged to the species lactobacillus reuteri (16/37; 43.3%), lactobacillus animalis (7/37; 18.9%), lactobacillus acidophilus (3/37; 8.1%), lactobacillus sanfranciscensis (2/37; 5.4%), lactobacillus ...201323538205
selection of dna aptamers for capture and detection of salmonella typhimurium using a whole-cell selex approach in conjunction with cell sorting.alternative ligands such as nucleic acid aptamers can be used for pathogen capture and detection and offer advantages over antibodies, including reduced cost, ease of production and modification, and improved stability. dna aptamers demonstrating binding specificity to salmonella enterica serovar typhimurium were identified by whole-cell-systematic evolution of ligands by exponential enrichment (selex) beginning with a combinatorial library of biotin-labeled single stranded dna molecules. aptame ...201323494620
antimicrobial activity of essential oils from mediterranean aromatic plants against several foodborne and spoilage bacteria.the antimicrobial activity of essential oils extracted from a variety of aromatic plants, often used in the portuguese gastronomy was studied in vitro by the agar diffusion method. the essential oils of thyme, oregano, rosemary, verbena, basil, peppermint, pennyroyal and mint were tested against gram-positive (listeria monocytogenes, clostridium perfringens, bacillus cereus, staphylococcus aureus, enterococcus faecium, enterococcus faecalis, and staphylococcus epidermidis) and gram-negative stra ...201323444311
inhibitory effect of cinnamon powder on pathogen growth in laboratory media and oriental-style rice cakes (sulgidduk).there has been an increasing interest in the use of natural plant materials as alternative food preservatives. we examined the antimicrobial effects of natural plant materials used as additives against foodborne pathogens in laboratory media and sulgidduk, oriental-style rice cakes. cinnamon, mugwort, and garlic powder solutions (3%) were tested for their antimicrobial activities against pathogens in laboratory media. sulgidduk prepared with different amounts of cinnamon powder (1, 3, and 6%) wa ...201323317869
[determination of the antimicrobial capacity of green tea (camellia sinensis) against the potentially pathogenic microorganisms escherichia coli, salmonella enterica, staphylococcus aureus, listeria monocytogenes, candida albicans and aspergillus niger].many studies can be found in scientific literature demonstrating the antimicrobial capacity of different herbs, including green tea. never-theless, many results are divergent or cannot be compared. several green tea formulations may be found in market, but there is scarce or non-information about its activity. in this work, the potential antimicrobial effect of 50 samples of dry green tea and in 10% infusion against escherichia coli, salmonella enterica, listeria monocytogenes, staphylococcus au ...201325362825
antibacterial/antifungal activity and synergistic interactions between polyprenols and other lipids isolated from ginkgo biloba l. leaves.polyprenols separated from lipids are promising new components from ginkgo biloba l. leaves (gbl). in this paper, ginkgo lipids were isolated by extraction with petroleum ether, saponification, and molecular distillation. eight known compounds: isophytol (1), nerolidol (2), linalool (3), β-sitosterol acetate (4), β-sitosterol (5), stigmasterol (6), ergosterol (7), β-sitosterol-3-o-β-d-glucopyranoside (8) and ginkgo biloba polyprenols (gbp) were separated from gbl by chromatography and identified ...201323434869
the selectable antibiotic marker, teta(c), increases pseudomonas aeruginosa susceptibility to the herbicide/superoxide generator, paraquat.the presence of the widely used selectable antibiotic marker, teta(c), unexpectedly increased the sensitivity of pseudomonas aeruginosa pao1 to the superoxide-generating herbicide, paraquat. a dna fragment spanning the first 99 amino acids of teta(c) was sufficient to confer paraquat sensitivity. the teta(c)-induced paraquat sensitive phenotype was observed in other gram-negative bacteria such as agrobacterium tumefaciens, salmonella enterica ser. typhimurium and xanthomonas campestris suggestin ...201323907582
inactivation of pathogens in feces by desiccation and urea treatment for application in urine-diverting dry toilets.ecological sanitation technologies can be effective in providing health and environmental pollution control if they can efficiently reduce the pathogenicity of microorganisms carried in fecal material to safe levels. this study evaluated the sanitizing effects of different additives for dry treatment of feces from urine-diverting dry toilets, based on inactivation of enterococcus faecalis, salmonella enterica serovar typhimurium, bacteriophages ms2 and φx, and ascaris suum. the additives, ash (a ...201323335764
transcription networks responsible for early regulation of salmonella-induced inflammation in the jejunum of pigs.the aim of this study was to identify transcription factors/regulators that play a crucial role in steering the (innate) immune response shortly (within a few hours) after the first contact of the intestinal mucosa with an inflammatory mediator, and to test whether the processes regulated by these factors/regulators can be modulated by chemical substances of natural origin.201323590759
immunogenicity of recombinant proteins consisting of plasmodium vivax circumsporozoite protein allelic variant-derived epitopes fused with salmonella enterica serovar typhimurium flagellin.a plasmodium falciparum circumsporozoite protein (csp)-based recombinant fusion vaccine is the first malaria vaccine to reach phase iii clinical trials. resistance to infection correlated with the production of antibodies to the immunodominant central repeat region of the csp. in contrast to p. falciparum, vaccine development against the csp of plasmodium vivax malaria is far behind. based on this gap in our knowledge, we generated a recombinant chimeric protein containing the immunodominant cen ...201323863502
antibacterial, antioxidant, and anticholinesterase activities of plant seed extracts from brazilian semiarid region.the antimicrobial, antioxidant, and anticholinesterase activities of ethanolic seed extracts of twenty-one plant species from brazilian semiarid region were investigated. the extracts were tested for antimicrobial activity against six bacteria strains and three yeasts. six extracts presented activity against the gram (-) organism salmonella choleraesuis and the gram (+) organisms staphylococcus aureus and bacillus subtilis. the mic values ranged from 4.96 to 37.32 mg/ml. the triplaris gardnerian ...201324386637
virulence and stress-related periplasmic protein (visp) in bacterial/host associations.gram-negative bacteria have an outer membrane containing lps. lps is constituted of an oligosaccharide portion and a lipid-a moiety that embeds this molecule within the outer membrane. lps is a pathogen-associated molecular pattern, and several pathogens modify their lipid-a as a stealth strategy to avoid recognition by the innate immune system and gain resistance to host factors that disrupt the bacterial cell envelope. an essential feature of salmonella enterica typhimurium pathogenesis is its ...201323302685
synthesis and anti-microbial potencies of 1-(2-hydroxyethyl)-3-alkylimidazolium chloride ionic liquids: microbial viabilities at different ionic liquids concentrations.three 1-(2-hydroxyethyl)-3-alkylimidazolium chloride room temperature ionic liquids (ils) [2ohimc(n)][cl]; (n=0, 1, 4) have been synthesized from the appropriate imidazole precursors and characterized by ir and nmr spectroscopies and elemental analysis. their anti-microbial activities were investigated using the well-diffusion method. the viabilities of escherichia coli, aeromonas hydrophila, listeria monocytogenes and salmonella enterica as a function of il concentrations were studied. the mini ...201323107478
screening of microbial contamination and antimicrobial activity of sea cucumber holothuria polii.microbiological studies were carried out on microbial contamination and antimicrobial activity of sea cucumber holothuria polii collected from mediterranean sea at abu-kir shore of alexandria, egypt. the obtained results revealed the presence of isolates of five human gram-negative pathogenic bacteria, representing five genera were identified to species level, including, esherichia coli, klebsiella pneumoniae, pseudomonas aeruginosa, salmonella sp. and shigella sp. in addition, an yeast candida ...201322653870
the tip of the tail needle affects the rate of dna delivery by bacteriophage p22.the p22-like bacteriophages have short tails. their virions bind to their polysaccharide receptors through six trimeric tailspike proteins that surround the tail tip. these short tails also have a trimeric needle protein that extends beyond the tailspikes from the center of the tail tip, in a position that suggests that it should make first contact with the host's outer membrane during the infection process. the base of the needle serves as a plug that keeps the dna in the virion, but role of th ...201323951045
mapping and regulation of genes within salmonella pathogenicity island 12 that contribute to in vivo fitness of salmonella enterica serovar typhimurium.salmonella pathogenicity island 12 (spi-12) of salmonella enterica serovar typhimurium is a 15-kb region that encompasses genes stm2230 to stm2245 and encodes a remnant phage known to contribute to bacterial virulence. in mouse infection experiments and replication assays in macrophages, we demonstrated a role for four genes in spi-12 for bacterial survival in the host. stm2239, a potential q antiterminator, showed a prominent contribution to bacterial fitness. transcriptional reporter experimen ...201323630960
dsba and mgrb regulate stea expression through the two-component system phoq/phop in salmonella enterica.stea is a protein that can be translocated into host cells through the two virulence-related type iii secretion systems that are present in salmonella enterica. we used the t-pop system to carry out general screens for loci that exhibited activation or repression of a stea::lacz fusion. these screens identified the histidine kinase phoq and the response regulator phop as positive regulators of stea. transcription of this gene is σ70 dependent, and the promoter of stea contains a phop-binding sit ...201323504014
antibiotic resistance in salmonella typhimurium associates with crispr sequence type.salmonella enterica subspecies enterica serovar typhimurium is a leading cause of foodborne salmonellosis in the united states. the number of antibiotic resistant isolates identified in humans is steadily increasing, suggesting that the spread of antibiotic resistant strains is a major threat to public health. s. typhimurium is commonly identified in a wide range of animal hosts, food sources, and environments, but little is known about the factors mediating the spread of antibiotic resistance i ...201323796925
ingress of salmonella enterica typhimurium into tomato leaves through hydathodes.internal contamination of salmonella in plants is attracting increasing attention for food safety reasons. in this study, three different tomato cultivars "florida lanai", "crown jewel", "ailsa craig" and the transgenic line sp5 of "ailsa craig" were inoculated with 1 µl gfp-labeled salmonella typhimurium through guttation droplets at concentrations of 10(9) or 10(7) cfu/ml. survival of salmonella on/in tomato leaves was detected by both direct plating and enrichment methods. salmonella cells su ...201323320087
a new protocol to detect multiple foodborne pathogens with pcr dipstick dna chromatography after a six-hour enrichment culture in a broad-range food pathogen enrichment broth.a quick foodborne pathogen screening method after six-hour enrichment culture with a broad-range food pathogen enrichment broth is described. pathogenic factors of salmonella enterica, shigella spp., enteroinvasive escherichia coli, and enterohemorrhagic e. coli are amplified with a cocktail primer and rapid polymerase chain reaction (pcr), which finishes amplification in 30 min. the pcr amplicon was differentiated with a dipstick dna chromatography assay in 5-10 min. starting from a four- to si ...201324364031
a small rna activates cfa synthase by isoform-specific mrna stabilization.small rnas use a diversity of well-characterized mechanisms to repress mrnas, but how they activate gene expression at the mrna level remains not well understood. the predominant activation mechanism of hfq-associated small rnas has been translational control whereby base pairing with the target prevents the formation of an intrinsic inhibitory structure in the mrna and promotes translation initiation. here, we report a translation-independent mechanism whereby the small rna rydc selectively act ...201324141880
genetic characterization of atypical citrobacter freundii.the ability of a bacterial population to survive in different niches, as well as in stressful and rapidly changing environmental conditions, depends greatly on its genetic content. to survive such fluctuating conditions, bacteria have evolved different mechanisms to modulate phenotypic variations and related strategies to produce high levels of genetic diversity. laboratories working in microbiological diagnosis have shown that citrobacter freundii is very versatile in its colony morphology, as ...201324069274
an rpos-dependent srna regulates the expression of a chaperone involved in protein folding.small noncoding rnas (srnas) are usually expressed in the cell to face a variety of stresses. in this report we disclose the first target for sral (also known as ryja), a srna present in many bacteria, which is highly induced in stationary phase. we also demonstrate that this srna is directly transcribed by the major stress σ factor σ(s) (rpos) in salmonella enterica serovar typhimurium. we show that sral srna down-regulates the expression of the chaperone trigger factor (tf), encoded by the tig ...201323893734
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