Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
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| ccr5 polymorphism and plague resistance in natural populations of the black rat in madagascar. | madagascar remains one of the world's largest plague foci. the black rat, rattus rattus, is the main reservoir of plague in rural areas. this species is highly susceptible to plague in plague-free areas (low-altitude regions), whereas rats from the plague focus areas (central highlands) have evolved a disease-resistance polymorphism. we used the candidate gene ccr5 to investigate the genetic basis of plague resistance in r. rattus. we found a unique non-synonymous substitution (h184r) in a funct ... | 2008 | 18703167 |
| a nasal interleukin-12 dna vaccine coexpressing yersinia pestis f1-v fusion protein confers protection against pneumonic plague. | previous studies have shown that mucosal application of interleukin-12 (il-12) can stimulate elevated secretory immunoglobulin a (iga) responses. since possible exposure to plague is via yersinia pestis-laden aerosols that results in pneumonic plague, arming both the mucosal and systemic immune systems may offer an added benefit for protective immunity. two bicistronic plasmids were constructed that encoded the protective plague epitopes, capsular antigen (f1-ag) and virulence antigen (v-ag) as ... | 2008 | 18694965 |
| evidence of multiple zoonotic agents in a wild rodent community in the eastern sierra nevada. | this study aimed to describe the occurrence of yersinia pestis, rickettsia rickettsii, anaplasma phagocytophilum, and ectoparasites in a wild rodent community in the eastern sierra nevada. from may to september 2006, rodents were live-trapped, examined for ectoparasites, and blood was collected. all rodents were serologically tested for antibodies to y. pestis, r. rickettsii, and a. phagocytophilum; in addition, blood samples and ectoparasites were tested by pcr to detect the presence of these z ... | 2008 | 18689664 |
| prevalence of yersinia pestis in rodents and fleas associated with black-tailed prairie dogs (cynomys ludovicianus) at thunder basin national grassland, wyoming. | rodents (and their fleas) that are associated with prairie dogs are considered important for the maintenance and transmission of the bacterium (yersinia pestis) that causes plague. our goal was to identify rodent and flea species that were potentially involved in a plague epizootic in black-tailed prairie dogs at thunder basin national grassland. we collected blood samples and ectoparasites from rodents trapped at off- and on-colony grids at thunder basin national grassland between 2002 and 2004 ... | 2008 | 18689663 |
| exposure of small rodents to plague during epizootics in black-tailed prairie dogs. | plague, caused by the bacterium yersinia pestis, causes die-offs of colonies of prairie dogs (cynomys ludovicianus). it has been argued that other small rodents are reservoirs for plague, spreading disease during epizootics and maintaining the pathogen in the absence of prairie dogs; yet there is little empirical support for distinct enzootic and epizootic cycles. between 2004 and 2006, we collected blood from small rodents captured in colonies in northern colorado before, during, and for up to ... | 2008 | 18689662 |
| [study on the situation of plague in junggar basin of china]. | to understand the distribution, fauna, population structure of host animals and their parasitic fleas as well as popular dynamic of animal plague of natural plague foci in junggar basin. | 2008 | 18686853 |
| cloning and functional expression of an alpha-galactosidase from yersinia pestis biovar microtus str. 91001. | a gene encoding a glycoside hydrolase (gh) family 36 alpha-galactosidase was cloned from yersinia pestis biovar microtus str. 91001 and expressed in escherichia coli. the purified recombinant alpha-galactosidase (aga-y) was optimally active at 37 degrees c and ph 6.8. the features of temperature profile, thermoliability, kinetics, and amino acid composition indicated that aga-y had properties of a cold-adapted enzyme. | 2008 | 18685186 |
| characterization of chromosomal regions conserved in yersinia pseudotuberculosis and lost by yersinia pestis. | the transformation of the enteropathogenic bacterium yersinia pseudotuberculosis into the plague bacillus, yersinia pestis, has been accompanied by extensive genetic loss. this study focused on chromosomal regions conserved in y. pseudotuberculosis and lost during its transformation into y. pestis. an extensive pcr screening of 78 strains of the two species identified five regions (r1 to r5) and four open reading frames (orfs; orf1 to orf4) that were conserved in y. pseudotuberculosis and absent ... | 2008 | 18678673 |
| the abundance threshold for plague as a critical percolation phenomenon. | percolation theory is most commonly associated with the slow flow of liquid through a porous medium, with applications to the physical sciences. epidemiological applications have been anticipated for disease systems where the host is a plant or volume of soil, and hence is fixed in space. however, no natural examples have been reported. the central question of interest in percolation theory, the possibility of an infinite connected cluster, corresponds in infectious disease to a positive probabi ... | 2008 | 18668107 |
| detection of viable yersinia pestis by fluorescence in situ hybridization using peptide nucleic acid probes. | a successful method has been developed for the detection of live yersinia pestis, the plague bacillus, which incorporates nascent rna synthesis. a fluorescent in situ hybridization (fish) assay using peptide nucleic acid (pna) probes was developed specifically to differentiate y. pestis strains from closely related bacteria. pna probes were chosen to target high copy mrna of the y. pestis caf1 gene, encoding the fraction 1 (f1) antigen, and 16s ribosomal rna. among yersinia strains tested, pna p ... | 2008 | 18655809 |
| alexandre yersin (1863-1943): discoverer of the plague bacillus, explorer and agronomist. | alexandre yersin was born in french switzerland and later took french nationality. while a medical student he worked in paris with emile roux to discover the exotoxin produced by the diphtheria bacillus. two years after graduation, he left paris for french indochina where he was the first european to explore and map the central highlands of vietnam. as a member of the french colonial health service he was sent to hong kong in 1894 to investigate the outbreak of bubonic plague. he isolated from b ... | 2008 | 18653838 |
| inhibition of mg2+ binding and dna religation by bacterial topoisomerase i via introduction of an additional positive charge into the active site region. | among bacterial topoisomerase i enzymes, a conserved methionine residue is found at the active site next to the nucleophilic tyrosine. substitution of this methionine residue with arginine in recombinant yersinia pestis topoisomerase i (ytop) was the only substitution at this position found to induce the sos response in escherichia coli. overexpression of the m326r mutant ytop resulted in approximately 4 log loss of viability. biochemical analysis of purified y. pestis and e. coli mutant topoiso ... | 2008 | 18653534 |
| dynamics of genome rearrangement in bacterial populations. | genome structure variation has profound impacts on phenotype in organisms ranging from microbes to humans, yet little is known about how natural selection acts on genome arrangement. pathogenic bacteria such as yersinia pestis, which causes bubonic and pneumonic plague, often exhibit a high degree of genomic rearrangement. the recent availability of several yersinia genomes offers an unprecedented opportunity to study the evolution of genome structure and arrangement. we introduce a set of stati ... | 2008 | 18650965 |
| plasminogen activator pla of yersinia pestis utilizes murine dec-205 (cd205) as a receptor to promote dissemination. | yersinia pestis, a gram-negative bacterium that causes bubonic and pneumonic plague, is able to rapidly disseminate to other parts of its mammalian hosts. y. pestis expresses plasminogen activator (pla) on its surface, which has been suggested to play a role in bacterial dissemination. it has been speculated that y. pestis hijacks antigen-presenting cells, such as macrophages (mphis) and dendritic cells, to be delivered to lymph nodes to initiate dissemination and infection. both alveolar mphis ... | 2008 | 18650418 |
| a multicopy suppressor screening approach as a means to identify antibiotic resistance determinant candidates in yersinia pestis. | yersinia pestis is the causative agent of plague and a potential agent of bioterrorism and biowarfare. the plague biothreat and the emergence of multidrug-resistant plague underscore the need to increase our understanding of the intrinsic potential of y. pestis for developing antimicrobial resistance and to anticipate the mechanisms of resistance that may emerge in y. pestis. identification of y. pestis genes that, when overexpressed, are capable of reducing antibiotic susceptibility is a useful ... | 2008 | 18644132 |
| a glycan shield for bacterial sphingolipids. | in this issue of chemistry & biology, kinjo et al. (2008) propose that the addition of oligosaccharides to the core outer membrane glycosphingolipid in sphingomonas spp. may be an adaptation that allows bacteria to evade recognition by natural killer t cells, thus suggesting a remarkable process of host/pathogen coevolution. | 2008 | 18634999 |
| insight into microevolution of yersinia pestis by clustered regularly interspaced short palindromic repeats. | yersinia pestis, the pathogen of plague, has greatly influenced human history on a global scale. clustered regularly interspaced short palindromic repeat (crispr), an element participating in immunity against phages' invasion, is composed of short repeated sequences separated by unique spacers and provides the basis of the spoligotyping technology. in the present research, three crispr loci were analyzed in 125 strains of y. pestis from 26 natural plague foci of china, the former soviet union an ... | 2008 | 18612419 |
| combating the threat of anthrax: a quantitative structure-activity relationship approach. | bacterial agents or products more likely to be used as biological weapons of mass destruction are bacillus anthracis, francisella tularensis, yersinia pestis, and the neurotoxin of clostridium botulinum. anthrax is an acute infectious disease with a high mortality rate caused by bacillus anthracis, reinforcing the need for better adjunctive therapy and prevention strategies. in this paper, we developed 7 qsar models on penicillin-based inhibitors of the class a and b beta-lactamases from b. anth ... | 2008 | 18611038 |
| development of a real-time quantitative pcr assay to enumerate yersinia pestis in fleas. | a real-time quantitative polymerase chain reaction (qpcr) assay was developed for yersina pestis. the qpcr assay was developed utilizing a conserved region of the y. pestis ferric iron uptake regulator gene (fur) to design primers and a fluorescent (fam-labeled) taqman probe. the assay was optimized using cultured y. pestis (ug05-0454) and was confirmed to work with strains from 3 y. pestis biovars. the optimized assay was capable of detecting a single organism of cultured y. pestis and as littl ... | 2008 | 18606771 |
| prevalence and abundance of fleas in black-tailed prairie dog burrows: implications for the transmission of plague (yersinia pestis). | plague, the disease caused by the bacterium yersinia pestis, can have devastating impacts on north american wildlife. epizootics, or die-offs, in prairie dogs (cynomys ludovicianus) occur sporadically and fleas (siphonaptera) are probably important in the disease's transmission and possibly as maintenance hosts of y. pestis between epizootics. we monitored changes in flea abundance in prairie dog burrows in response to precipitation, temperature, and plague activity in shortgrass steppe in north ... | 2008 | 18605787 |
| induction of innate immunity by lipid a mimetics increases survival from pneumonic plague. | this study analysed the effect of priming the innate immune system using synthetic lipid a mimetics in a yersinia pestis murine pulmonary infection model. two aminoalkyl glucosaminide 4-phosphate (agp) toll-like receptor 4 (tlr4) ligands, delivered intranasally, extended time to death or protected against a lethal y. pestis co92 challenge. the level of protection was dependent upon the challenge dose of y. pestis and the timing of agp therapy. protection correlated with cytokine induction and a ... | 2008 | 18599840 |
| characterization of a mouse model of plague after aerosolization of yersinia pestis co92. | yersinia pestis is a gram-negative bacterium, and the causative agent of bubonic plague and pneumonic plague. because of its potential use as a biological warfare weapon, the plague bacterium has been placed on the list of category a select agents. the dynamics of pneumonic infection following aerosolization of the highly virulent y. pestis co92 strain have been poorly studied; therefore, the purpose of this study was to determine the ld(50) dose, bacterial dissemination, cytokine/chemokine prod ... | 2008 | 18599822 |
| [genetic and molecular characters of toxin producing erwinia chrysanthemi pv. zeae]. | bacterial foot rot, caused by erwinia chrysanthemi pv. zeae, is one of the most important diseases in rice. genetic and molecular characters of toxin producting for erwinia chrysanthemi pv. zeae were conducted in this paper. | 2008 | 18590228 |
| oligomerization of pcrv and lcrv, protective antigens of pseudomonas aeruginosa and yersinia pestis. | protective antigens of pseudomonas aeruginosa (pcrv) and yersinia pestis (lcrv) are key elements of specialized machinery, the type iii secretion system (t3ss), which enables the injection of effector molecules into eukaryotic cells. being positioned at the injectisome extremity, v proteins participate in the translocation process across the host cell plasma membrane. in this study, we demonstrate the assembly of v proteins into oligomeric doughnut-like complexes upon controlled refolding of the ... | 2008 | 18583342 |
| plague today. | 2008 | 18575085 | |
| the archaeology of "plague". | 2008 | 18575084 | |
| epidemiology of the black death and successive waves of plague. | 2008 | 18575083 | |
| medieval and modem bubonic plague: some clinical continuities. | 2008 | 18575082 | |
| the language of plague and its regional perspectives: the case of medieval germany. | 2008 | 18575081 | |
| universal and particular: the language of plague, 1348-1500. | 2008 | 18575080 | |
| pestilential complexities: understanding medieval plague. | 2008 | 18575079 | |
| the resistance of balb/cj mice to yersinia pestis maps to the major histocompatibility complex of chromosome 17. | yersinia pestis, the causative agent of plague, has been well studied at the molecular and genetic levels, but little is known about the role that host genes play in combating this highly lethal pathogen. we challenged several inbred strains of mice with y. pestis and found that balb/cj mice are highly resistant compared to susceptible strains such as c57bl/6j. this resistance was observed only in balb/cj mice and not in other balb/c substrains. compared to c57bl/6j mice, the balb/cj strain exhi ... | 2008 | 18573896 |
| inhibition of expression of virulence genes of yersinia pestis in escherichia coli by external guide sequences and rnase p. | external guide sequences (egss) targeting virulence genes from yersinia pestis were designed and tested in vitro and in vivo in escherichia coli. linear egss and m1 rna-linked egss were designed for the yscn and yscs genes that are involved in type iii secretion in y. pestis. rnase p from e. coli cleaves the messages of yscn and yscs in vitro with the cognate egss, and the expression of the egss resulted in the reduction of the levels of these messages of the virulence genes when those genes wer ... | 2008 | 18567813 |
| an age-old paradigm challenged: old baboons generate vigorous humoral immune responses to lcrv, a plague antigen. | immune senescence in the elderly results in decreased immunity with a concomitant increase in susceptibility to infection and diminished efficacy of vaccination. nonhuman primate models have proven critical for testing of vaccines and therapeutics in the general population, but a model using old animals has not been established. toward that end, immunity to lcrv, a protective ag from yersinia pestis, was tested in young and old baboons. surprisingly, there was no age-associated loss in immune co ... | 2008 | 18566375 |
| caspase-1 activation in macrophages infected with yersinia pestis kim requires the type iii secretion system effector yopj. | pathogenic yersinia species utilize a type iii secretion system (t3ss) to translocate effectors called yersinia outer proteins (yops) into infected host cells. previous studies demonstrated a role for effector yops in the inhibition of caspase-1-mediated cell death and secretion of interleukin-1beta (il-1beta) in naïve macrophages infected with yersinia enterocolitica. naïve murine macrophages were infected with a panel of different yersinia pestis and yersinia pseudotuberculosis strains to dete ... | 2008 | 18559430 |
| early-phase transmission of yersinia pestis by cat fleas (ctenocephalides felis) and their potential role as vectors in a plague-endemic region of uganda. | in recent decades, the majority of human plague cases (caused by yersinia pestis) have been reported from africa. in northwest uganda, which has had recent plague outbreaks, cat fleas (ctenocephalides felis) have been reported as the most common fleas in the home environment, which is suspected to be a major exposure site for human plague in this country. in the past, c. felis has been viewed as only a nuisance-biting insect because limited laboratory studies suggested it is incapable of transmi ... | 2008 | 18541775 |
| septicemic plague in a community hospital in california. | diagnosis of a case of septicemic plague acquired in rural california was delayed because of a series of confounding events, resulting in concern about reliance on community hospitals as sentinels for detecting potential bioterrorism-related events. an epizootic study confirmed the peridomestic source of yersinia pestis infection. | 2008 | 18541761 |
| a new purification strategy for fraction 1 capsular antigen and its efficacy against yersinia pestis virulent strain challenge. | f1 antigen is an attractive candidate for the development of a subunit vaccine against plague. in previous study, the extraction of this antigen from yersinia pestis is characterized by using organic solvents. in this work, a new purification strategy that produced high-purity f1 antigen from y. pestis ev76 was developed by the substitution of physical disruption for organic solvent one, followed by a combination of ammonium sulfate fractionation and sephacryl s-200hr column filtration chromatog ... | 2008 | 18539482 |
| conformational states and association mechanism of yersinia pestis caf1 subunits. | bacterial infectivity often relies on efficient attachment to the host cells through adhesive extensions. unveiling the structural basis of the formation of these organelles is of paramount importance for both academic and applicative implications. computational approaches may fruitfully complement experimental studies by providing information on specific conformational states whose characterization is difficult. here, we report molecular dynamics characterizations of yersinia pestis caf1 subuni ... | 2008 | 18534189 |
| microbial glyoxalase enzymes: metalloenzymes controlling cellular levels of methylglyoxal. | the glyoxalase system consists of two enzymes, glyoxalase i and glyoxalase ii. this system is important in the detoxification of methylglyoxal. detailed studies have determined that the glyoxalase i from escherichia coli, neisseria meningitidis and yersinia pestis are maximally activated by ni2+ and co2+, and are inactive with zn2+, a situation quite different from the human glyoxalase i enzyme, which is activated by zn2+. recent studies on the pseudomonas aeruginosa genome have led to the chara ... | 2008 | 18533363 |
| p19-dependent and p19-independent reversion of f1-v gene silencing in tomato. | as a part of a project to develop a plant-made plague vaccine, we expressed the yersinia pestis f1-v antigen fusion protein in tomato. we discovered that in some of these plants the expression of the f1-v gene was undetectable in leaves and fruit by elisa, even though they had multiple copies of f1-v according to southern-blot analysis. a likely explanation of these results is the phenomenon of rna silencing, a group of rna-based processes that produces sequence-specific inhibition of gene expre ... | 2008 | 18528764 |
| the yersinia pestis autotransporter yapc mediates host cell binding, autoaggregation and biofilm formation. | yapc, a putative yersinia pestis autotransporter protein, shows strong homology to the enterotoxigenic escherichia coli adhesin tiba. as a potentially important surface protein of y. pestis, we analysed yapc for several activities. when expressed in the non-pathogenic fim(-) e. coli strain aaec185, yapc mediated attachment to both murine-derived macrophage-like cells (raw264.7) and human-derived epithelial-like cells (hep-2). in addition, expression of yapc on the surface of e. coli led to autoa ... | 2008 | 18524935 |
| experimental evidence for negative selection in the evolution of a yersinia pestis pseudogene. | yersinia pestis, the agent of bubonic plague, evolved from the enteric pathogen yersinia pseudotuberculosis within the past 20,000 years. because ancestor and descendant both exist, it is possible to infer steps in molecular evolution by direct experimental approaches. the y. pestis life cycle includes establishment of a biofilm within its vector, the flea. although y. pseudotuberculosis makes biofilms in other environments, it fails to do so in the insect. we show that rcsa, a negative regulato ... | 2008 | 18523005 |
| the hmshfrs operon of xenorhabdus nematophila is required for biofilm attachment to caenorhabditis elegans. | the bacterium xenorhabdus nematophila is an insect pathogen and an obligate symbiont of the nematode steinernema carpocapsae. x. nematophila makes a biofilm that adheres to the head of the model nematode caenorhabditis elegans, a capability x. nematophila shares with the biofilms made by yersinia pestis and yersinia pseudotuberculosis. as in yersinia spp., the x. nematophila biofilm requires a 4-gene operon, hmshfrs. also like its yersinia counterparts, the x. nematophila biofilm is bound by the ... | 2008 | 18515487 |
| persistence of yersinia pestis in soil under natural conditions. | as part of a fatal human plague case investigation, we showed that the plague bacterium, yersinia pestis, can survive for at least 24 days in contaminated soil under natural conditions. these results have implications for defining plague foci, persistence, transmission, and bioremediation after a natural or intentional exposure to y. pestis. | 2008 | 18507908 |
| effective plague vaccination via oral delivery of plant cells expressing f1-v antigens in chloroplasts. | the chloroplast bioreactor is an alternative to fermentation-based systems for production of vaccine antigens and biopharmaceuticals. we report here expression of the plague f1-v fusion antigen in chloroplasts. site-specific transgene integration and homoplasmy were confirmed by pcr and southern blotting. mature leaves showed the highest level of transgene expression on the third day of continuous illumination, with a maximum level of 14.8% of the total soluble protein. swiss webster mice were p ... | 2008 | 18505806 |
| oral vaccination against bubonic plague using a live avirulent yersinia pseudotuberculosis strain. | we evaluated the possibility of using yersinia pseudotuberculosis as a live vaccine against plague because it shares high genetic identity with y. pestis while being much less virulent, genetically much more stable, and deliverable orally. a total of 41 y. pseudotuberculosis strains were screened by pcr for the absence of the high pathogenicity island, the superantigens ypm, and the type iv pilus and the presence of the pyv virulence plasmid. one strain (ip32680) fulfilled these criteria. this s ... | 2008 | 18505804 |
| adrenal gland hemorrhage in patients with fatal bacterial infections. | a wide spectrum of adrenal gland pathology is seen during bacterial infections. hemorrhage is particularly associated with meningococcemia, while abscesses have been described with several neonatal infections. we studied adrenal gland histopathology of 65 patients with bacterial infections documented in a variety of tissues by using immunohistochemistry. the infections diagnosed included neisseria meningitidies, group a streptococcus, rickettsia rickettsii, streptococcus pneumoniae, staphylococc ... | 2008 | 18500257 |
| yersinia pestis type iii secretion system-dependent inhibition of human polymorphonuclear leukocyte function. | human polymorphonuclear leukocytes (pmns, or neutrophils) are the primary innate host defense against invading bacterial pathogens. neutrophils are rapidly recruited to sites of infection and ingest microorganisms through a process known as phagocytosis. following phagocytosis by human pmns, microorganisms are killed by reactive oxygen species (ros) and microbicidal products contained within granules. yersinia pestis, the causative agent of plague, is capable of rapid replication and disseminati ... | 2008 | 18490459 |
| dog-associated risk factors for human plague. | plague is a rare but often fatal zoonosis endemic to the western united states. previous studies have identified contact with pets as a potential risk factor for infection. we conducted a matched case-control study to better define the risks associated with pets at both the household and individual levels. using a written questionnaire, we surveyed nine surviving plague patients, 12 household members of these patients, and 30 age- and neighbourhood-matched controls about household and individual ... | 2008 | 18489541 |
| [a study of the nucleotide sequence variability of rha locus genes of yersinia pestis main and non-main subspecies]. | a study of the structural and regulatory genes, determining rhamnose fermentation, that are located in the rha locus of the chromosome of yersinia pestis main and non-main subspecies and of yersinia pseudotuberculosis of serogroups i-iii was performed. the nucleotide sequence of y. pestis main subspecies differs substantially from those of non-main subspecies and y. pseudotuberculosis by the presence of a nucleotide substitution in 671 bp location of rhas gene resulting presumably in the y. pest ... | 2008 | 18488445 |
| highly efficient method for introducing successive multiple scarless gene deletions and markerless gene insertions into the yersinia pestis chromosome. | an efficient two-step recombination method for markerless gene deletion and insertion that can be used for repetitive genetic modification in yersinia pestis was developed. the method combines lambda red recombination and counterselective screening (sacb gene) and can be used for genetic modification of y. pestis to construct live attenuated vaccines. | 2008 | 18487404 |
| modified caspase-3 assay indicates correlation of caspase-3 activity with immunity of nonhuman primates to yersinia pestis infection. | defined candidate human vaccines for treating infection by yersinia pestis, the agent of plague, have been developed. to facilitate evaluation of the vaccines' efficacy, the in vitro caspase-3 assay for cytotoxicity-neutralizing activity was modified and reevaluated. immune serum-mediated caspase-3 neutralizing activity correlated with protection against infection in a nonhuman primate vaccine model of plague immunity. | 2008 | 18480233 |
| different region analysis for genotyping yersinia pestis isolates from china. | dfr (different region) analysis has been developed for typing yesinia pestis in our previous study, and in this study, we extended this method by using 23 dfrs to investigate 909 chinese y. pestis strains for validating dfr-based genotyping method and better understanding adaptive microevolution of y. pestis. | 2008 | 18478120 |
| physiological and regulatory characterization of kata and katy in yersinia pestis. | the catalase or catalase-peroxidase activity commonly exists in many pathogens and plays an important role in resisting the oxidative burst of phagocytes helping the pathogen persistently colonize in the host. yersinia pestis is a facultative pathogen and the causative agent of plague. katy has been identified as a thermosensing antigen with modest catalase activity in this pathogen. here y. pestis kata and katy were experimentally confirmed as a monofunctional catalase and bifunctional catalase ... | 2008 | 18466088 |
| oropsylla hirsuta (siphonaptera: ceratophyllidae) can support plague epizootics in black-tailed prairie dogs (cynomys ludovicianus) by early-phase transmission of yersinia pestis. | plague, caused by the bacterium yersinia pestis, often leads to rapid decimation of black-tailed prairie dog colonies. flea-borne transmission of y. pestis has been thought to occur primarily via blocked fleas, and therefore studies of vector efficiency have focused on the period when blockage is expected to occur (> or =5 days post-infection [p.i.]). oropsylla hirsuta, a prairie dog flea, rarely blocks and transmission is inefficient > or =5 days p.i.; thus, this flea has been considered incapa ... | 2008 | 18454591 |
| a support vector machine model for the prediction of proteotypic peptides for accurate mass and time proteomics. | the standard approach to identifying peptides based on accurate mass and elution time (amt) compares profiles obtained from a high resolution mass spectrometer to a database of peptides previously identified from tandem mass spectrometry (ms/ms) studies. it would be advantageous, with respect to both accuracy and cost, to only search for those peptides that are detectable by ms (proteotypic). | 2008 | 18453551 |
| yersinia pestis biofilm in the flea vector and its role in the transmission of plague. | transmission by fleabite is a relatively recent evolutionary adaptation of yersinia pestis, the bacterial agent of bubonic plague. to produce a transmissible infection, y. pestis grows as an attached biofilm in the foregut of the flea vector. biofilm formation both in the flea foregut and in vitro is dependent on an extracellular matrix (ecm) synthesized by the yersinia hms gene products. the hms genes are similar to the pga and ica genes of escherichia coli and staphylococcus epidermidis, respe ... | 2008 | 18453279 |
| a missense mutation causes aspartase deficiency in yersinia pestis. | it is established that cells of yersinia pestis, the causative agent of bubonic plague, excrete l-aspartic acid at the expense of exogenous l-glutamic acid during expression of the low-calcium response. results of enzymic analysis provided here suggest that a previously defined deficiency of aspartase (aspa) accounts for this phenomenon rather than an elevated oxaloacetate pool. the only known distinction between most sequenced isolates of aspa from y. pestis and the active gene in yersinia pseu ... | 2008 | 18451035 |
| no evidence of deer mouse involvement in plague (yersinia pestis) epizootics in prairie dogs. | plague, the disease caused by the bacterium yersinia pestis, can have devastating impacts on black-tailed prairie dog (cynomys ludovicianus) colonies. one suggested mechanism behind sporadic prairie dog die-offs involves an alternative mammal host, such as the deer mouse (peromyscus maniculatus), which often inhabits prairie dog colonies. we examined the flea populations of deer mice to investigate the potential of flea-borne transmission of plague between deer mice and prairie dogs in northern ... | 2008 | 18447619 |
| retargeting r-type pyocins to generate novel bactericidal protein complexes. | r-type pyocins are high-molecular-weight bacteriocins that resemble bacteriophage tail structures and are produced by some pseudomonas aeruginosa strains. r-type pyocins kill by dissipating the bacterial membrane potential after binding. the high-potency, single-hit bactericidal kinetics of r-type pyocins suggest that they could be effective antimicrobials. however, the limited antibacterial spectra of natural r-type pyocins would ultimately compromise their clinical utility. the spectra of thes ... | 2008 | 18441117 |
| a high-throughput pipeline for designing microarray-based pathogen diagnostic assays. | we present a methodology for high-throughput design of oligonucleotide fingerprints for microarray-based pathogen diagnostic assays. the oligonucleotide fingerprints, or dna microarray probes, are designed for identifying target organisms in environmental or clinical samples. the design process is implemented in a high-performance computing software pipeline that incorporates major algorithmic improvements over a previous version to both reduce computation time and improve specificity assessment ... | 2008 | 18402679 |
| [healthcare response to bioterrorism]. | bioterrorists seek to use highly virulent pathogens to cause social and economic disruption. historical agents such as anthrax, yersinia pestis and botulinum toxin can easily be produced, whereas others such as hemorragic fever virus require much more sophisticated infrastructure and government-scale resources. in the near future, with the spread of new biotechnologies, bioterrorists may produce new transgenic pathogens. epidemiological surveillance and diagnostic capacities should thus be more ... | 2007 | 18402160 |
| [plague bacterium examination and epidemiology significance analysis of "three jiang yuan area" in qinghai province, china]. | 2007 | 18399164 | |
| small molecules with structural similarities to siderophores as novel antimicrobials against mycobacterium tuberculosis and yersinia pestis. | drugs inhibiting the iron scarcity-induced, siderophore-mediated iron-scavenging systems of mycobacterium tuberculosis (mtb) and yersinia pestis (yp) may provide new therapeutic lines of defense. compounds with structural similarities to siderophores were synthesized and evaluated as antimicrobials against mtb and yp under iron-limiting conditions, which mimic the iron scarcity these pathogens encounter and must adapt to in the host, and under standard iron-rich conditions for comparison. new an ... | 2008 | 18394884 |
| bioterrorism: class a agents and their potential presentations in immunocompromised patients. | a bioterrorism attack would be particularly challenging for medical professionals caring for patients with cancer who often have weakened immune systems. knowledge of the class a agents and the potential variable presentations in immunocompromised patients is key to early recognition of an outbreak and prompt reporting. the purpose of this article is to present the class a agents: bacillus anthracis (anthrax), botulinum toxin (botulism), variola virus (smallpox), yersinia pestis (pneumonic plagu ... | 2008 | 18390465 |
| characterizing the dynamic nature of the yersinia pestis periplasmic proteome in response to nutrient exhaustion and temperature change. | the periplasmic proteome of yersinia pestis strain kim6+ was characterized using differential 2-de display of proteins isolated from several subcellular fractions. circa 160 proteins were designated as periplasmic, including 62 (putative) solute-binding proteins of atp-binding cassette (abc) transporters (sbps) and 46 (putative) metabolic enzymes. more than 30 sbps were significantly increased in abundance during stationary phase cell growth, compared to the exponential phase. the data suggest t ... | 2008 | 18383009 |
| [quarantine infectious diseases and sanitary control of territories in modern conditions]. | 2008 | 18376467 | |
| the importance of the rcs phosphorelay in the survival and pathogenesis of the enteropathogenic yersiniae. | the human-pathogenic yersiniae represent an ideal species group to study the evolution of highly virulent bacteria, with yersinia pestis having emerged from the enteropathogen y. pseudotuberculosis an estimated 20 000 years ago. sequence data reveal that the y. pestis genome is in the early stages of decay and contains hundreds of non-functioning pseudogenes, some of which may be important in the enteric lifestyle of y. pseudotuberculosis. bioinformatic analysis of pseudogenes from seven y. pest ... | 2008 | 18375804 |
| rapid polymerase chain reaction-based screening assay for bacterial biothreat agents. | to design and evaluate a rapid polymerase chain reaction (pcr)-based assay for detecting eubacteria and performing early screening for selected class a biothreat bacterial pathogens. | 2008 | 18370996 |
| [biological and physico-chemical properties of yersinia pseudotuberculosis bacterial culture having the fra-operon yersinia pestis]. | the biological and physico-chemical properties of cultures of two isogenous recombinant variants of yersinia pseudotuberculosis were studied. the cell genomes of the cultures are distinguished from one another only by the presence or by the absence of the fra-operon, which is a determined attribute of the plague microbe capsule-forming process. the expression of the attribute is amplified by rising the microbial biomass cultivation temperature and stimulates the decrease in the viability of the ... | 2008 | 18368776 |
| [plague in china. threat of transmission to regions of siberia and far east]. | in china plague has been officially registered from 1754 (638 epidemics with total number of cases 2.5 millions and case-fatality rate 87.5%). endemic areas started to form on the south of the country and then the disease gradually spread on seaside provinces, where to the end of the 19th century, due to reach of island territories and large international seaports, was characterized by pandemic spread. epidemic manifestations of plague in china were observed during more than 200 years in 23 out ... | 2008 | 18368762 |
| [relations of the causative agents of plague and listeriosis during their simultaneous stay in the flea citellophilus tesquorum at different environmental temperatures]. | experiments were carried out to determine the persistence of a plague microbe with varying praline labeling (isolated in the central caucasian mountain focus of plague in the fleas citellophilus tesquorum of a mountain subspecies) in the contamination of the mixed culture of the plague microbe and listeria. inoculation of fleas with a suspension of a plague microbe and listeriae demonstrates the manifest signs of antagonism between both species of microorganisms. this is evidenced by the reducti ... | 2008 | 18368716 |
| mucosal adjuvant activity of flagellin in aged mice. | we evaluated the ability of flagellin, a highly effective mucosal adjuvant in mice and non-human primates, to promote mucosal innate and adaptive immunity in aged mice. we found that intratracheal instillation of flagellin induced a stronger respiratory innate response in aged mice than in young mice, and that intranasal instillation of flagellin was equally effective at triggering recruitment of t and b lymphocytes to the draining lymph nodes of young and aged mice. intranasal immunization of a ... | 2008 | 18367233 |
| identification and characterization of phop regulon members in yersinia pestis biovar microtus. | the transcription regulator phop has been shown to be important for y. pestis survival in macrophages and under various in vitro stresses. however, the mechanism by which phop promotes bacterial intracellular survival is not fully understood. our previous microarray analysis suggested that phop governed a wide set of cellular pathways in y. pestis. a series of biochemical experiments were done herein to study members of the phop regulon of y. pestis biovar microtus. | 2008 | 18366809 |
| rnase e regulates the yersinia type 3 secretion system. | yersinia spp. use a type 3 secretion system (t3ss) to directly inject six proteins into macrophages, and any impairment of this process results in a profound reduction in virulence. we previously showed that the exoribonuclease polynucleotide phosphorylase (pnpase) was required for optimal t3ss functioning in yersinia pseudotuberculosis and yersinia pestis. here we report that y. pseudotuberculosis cells with reduced rnase e activity are likewise impaired in t3ss functioning and that phenotypica ... | 2008 | 18359811 |
| technical note: a rapid diagnostic test detects plague in ancient human remains: an example of the interaction between archeological and biological approaches (southeastern france, 16th-18th centuries). | a rapid diagnostic test (rdt) that detects yersinia pestis f1 antigen was applied to 28 putative plague victims exhumed from seven burial sites in southeastern france dating to the 16th-18th centuries. yersinia pestis f1 antigen was detected in 19 of the 28 (67.9%) samples. the 27 samples used as negative controls yielded negative results. soil samples taken from archeological sites related to both positive and negative samples tested negative for f1 antigen. the detection threshold of the rdt f ... | 2008 | 18350578 |
| klebsiella pneumoniae multiresistance plasmid pmet1: similarity with the yersinia pestis plasmid pcry and integrative conjugative elements. | dissemination of antimicrobial resistance genes has become an important public health and biodefense threat. plasmids are important contributors to the rapid acquisition of antibiotic resistance by pathogenic bacteria. | 2008 | 18350140 |
| yersinia pestis caf1 variants and the limits of plague vaccine protection. | yersinia pestis, the highly virulent agent of plague, is a biological weapon. strategies that prevent plague have been sought for centuries, and immunization with live, attenuated (nonpigmented) strains or subunit vaccines with f1 (caf1) antigen is considered effective. we show here that immunization with live, attenuated strains generates plague-protective immunity and humoral immune responses against f1 pilus antigen and lcrv. y. pestis variants lacking caf1 (f1 pili) are not only fully virule ... | 2008 | 18347051 |
| uniquely insidious: yersinia pestis biofilms. | bubonic plague, one of history's deadliest infections, is transmitted by fleas infected with yersinia pestis. the bacteria can starve fleas by blocking their digestive tracts, which stimulates the insects to bite repeatedly and thereby infect new hosts. direct examination of infected fleas, aided by in vitro studies and experiments with the nematode caenorhabditis elegans, have established that y. pestis forms a biofilm in the insect. the extracellular matrix of the biofilm seems to contain a ho ... | 2008 | 18339547 |
| assays for the rapid and specific identification of north american yersinia pestis and the common laboratory strain co92. | we present taqman-minor groove binding (mgb) assays for an snp that separates the yersinia pestis strain co92 from all other strains and for another snp that separates north american strains from all other global strains. | 2008 | 18330347 |
| current challenges in the development of vaccines for pneumonic plague. | inhalation of yersinia pestis bacilli causes pneumonic plague, a rapidly progressing and exceptionally virulent disease. extensively antibiotic-resistant y. pestis strains exist and we currently lack a safe and effective pneumonic plague vaccine. these facts raise concern that y. pestis may be exploited as a bioweapon. here, i review the history and status of plague vaccine research and advocate that pneumonic plague vaccines should strive to prime both humoral and cellular immunity. | 2008 | 18324890 |
| macaque models of human infectious disease. | macaques have served as models for more than 70 human infectious diseases of diverse etiologies, including a multitude of agents-bacteria, viruses, fungi, parasites, prions. the remarkable diversity of human infectious diseases that have been modeled in the macaque includes global, childhood, and tropical diseases as well as newly emergent, sexually transmitted, oncogenic, degenerative neurologic, potential bioterrorism, and miscellaneous other diseases. historically, macaques played a major rol ... | 2008 | 18323583 |
| use of cethromycin, a new ketolide, for treatment of community-acquired respiratory infections. | the ketolides are a subclass of macrolides, which were designed specifically to overcome macrolide-resistant respiratory pathogens. ketolides lack the cladinose sugar, which is replaced with a 3-ketone group. ketolides bind to a secondary region on domain ii of the 23s rrna subunit. telithromycin was the first ketolide to be approved by the fda in 2004 for treatment of community-acquired pneumonia (cap), acute exacerbations of chronic bronchitis (aecb) and sinusitis. however, in 2006, after repo ... | 2008 | 18321237 |
| [resistance of experimental antibiotic resistant variants of yersinia pestis ev76 (niieg line) to modern marker antibiotics]. | lower susceptibility of previously designed experimental polyresistant variants of yersinia pestis ev76 (niieg line) with inserted r plasmid or transposons to some present antibiotics efficient in the treatment of plague, i. e. doxycycline, amikacin and ceftriaxone, was shown. clones, more resistant to them vs. the initial variants, were selected. they accustomed in vivo in laboratory animals per se and after administration of antibiotics. the data on the protective activity of the new variants ... | 2006 | 18318143 |
| biogenesis of the fraction 1 capsule and analysis of the ultrastructure of yersinia pestis. | analysis of a yersinia pestis delta caf1a mutant demonstrated that the caf1a usher is required for the assembly and secretion of the fraction 1 capsule. the capsule assembled into thin fibrils and denser aggregates on the bacterial surface. pilus-like fibers were also detected on the surface of y. pestis. the capsule occasionally coated these fibers, suggesting how the capsule may cloak surface features to prevent host recognition. | 2008 | 18310330 |
| design and preparation of non-tagged yersinia pestis lcrv antigen in escherichia coli and its immunogenicity in balb/c mice. | the whole encoding sequence for yersinia pestis lcrv antigen was cloned into pet-32a(+) and expressed in escherichia coli bl21 (de3). the lcrv was high level expressed in the e. coli cytoplasm in a completely soluble form. recombinant lcrv could be purified from the supernatant of the bacteria lysate after chromatography using a combination of phenyl-sepharose f f, deae-sepharose f f and hiload superdex 75. the final yield of approximately 3 g of purified rlcrv from 42 l bioreactor containing 25 ... | 2008 | 18309570 |
| neutralization of yersinia pestis-mediated macrophage cytotoxicity by anti-lcrv antibodies and its correlation with protective immunity in a mouse model of bubonic plague. | plague is a life-threatening disease caused by yersinia pestis, for which effective-licensed vaccines and reliable predictors of in vivo immunity are lacking. v antigen (lcrv) is a major y. pestis virulence factor that mediates translocation of the cytotoxic yersinia protein effectors (yops). it is a well-established protective antigen and a part of currently tested plague subunit vaccines. we have developed a highly sensitive in vitro macrophage cytotoxicity neutralization assay which is mediat ... | 2008 | 18304706 |
| defective innate cell response and lymph node infiltration specify yersinia pestis infection. | since its recent emergence from the enteropathogen yersinia pseudotuberculosis, y. pestis, the plague agent, has acquired an intradermal (id) route of entry and an extreme virulence. to identify pathophysiological events associated with the y. pestis high degree of pathogenicity, we compared disease progression and evolution in mice after id inoculation of the two yersinia species. mortality studies showed that the id portal was not in itself sufficient to provide y. pseudotuberculosis with the ... | 2008 | 18301765 |
| structural diversity and endotoxic activity of the lipopolysaccharide of yersinia pestis. | the endotoxic activity of the lipopolysaccharides (lps) with defined chemical structure from yersinia pestis strains of various subspecies differing in their epidemic potential was studied. the lps of two strains of y. pestis ssp. caucasica and ssp. altaica, whose structures have not been studied earlier, were analyzed by high-resolution mass spectrometry. in addition to reported structural changes, an increase in the degree of lps phosphorylation was observed when strain i-2377 (ssp. altaica) w ... | 2008 | 18298376 |
| characterisation of yersinia pestis isolates from natural foci of plague in the republic of georgia, and their relationship to y. pestis isolates from other countries. | forty yersinia pestis isolates from endemic foci of plague in the republic of georgia, and six y. pestis isolates from neighbouring former soviet union countries, were analysed for their biochemical and phenotypic properties, and their genetic relatedness was compared with y. pestis strains kim and co92 by pulsed-field gel electrophoresis (pfge). in addition, 11 y. pestis isolates from the usa, together with published nucleotide sequences from y. pestis strains kim, co92 and 91001, were compared ... | 2008 | 18294239 |
| relative immunogenicity and protection potential of candidate yersinia pestis antigens against lethal mucosal plague challenge in balb/c mice. | yersinia pestis outer proteins, plasminogen activator protease and yop secretion protein f are necessary for the full virulence of yesinia pestis and have been proposed as potential protective antigens for vaccines against plague. in the current study, we used dna immunization as a tool to study the relative protective immunity of these proteins with a standardized intranasal challenge system in mice. while the natural full-length gene sequences for most of these y. pestis proteins did not displ ... | 2008 | 18291562 |
| examining the vector-host-pathogen interface with quantitative molecular tools. | we developed pcr assays to detect and quantitate yersinia pestis, the bacterial agent of plague, in flea vector and mammalian host tissues. bacterial numbers in fleas, fleabite sites, and infected lymph nodes were determined using real-time pcr with primers and probes for a gene target on a multi-copy plasmid specific to y. pestis. tissue-matched standard curves used to determine absolute bacterial numbers in unknown samples were linear over at least five orders of magnitude. the methods were ap ... | 2008 | 18287752 |
| a quadruplex real-time pcr assay for the detection of yersinia pestis and its plasmids. | yersinia pestis, the aetiological agent of the plague, causes sporadic disease in endemic areas of the world and is classified as a national institute of allergy and infectious diseases category a priority pathogen because of its potential to be used as a bioweapon. health departments, hospitals and government agencies need the ability to rapidly identify and characterize cultured isolates of this bacterium. assays have been developed to perform this function; however, they are limited in their ... | 2008 | 18287295 |
| human dendritic cell-specific intercellular adhesion molecule-grabbing nonintegrin (cd209) is a receptor for yersinia pestis that promotes phagocytosis by dendritic cells. | yersinia pestis is the etiologic agent of bubonic and pneumonic plagues. it is speculated that y. pestis hijacks antigen-presenting cells (apcs), such as dendritic cells (dcs) and alveolar macrophages, in order to be delivered to lymph nodes. however, how apcs initially capture the bacterium remains uncharacterized. it is well known that hiv-1 uses human dc-specific intercellular adhesion molecule-grabbing nonintegrin (dc-sign) (cd209) receptor, expressed by apcs, to be captured and delivered to ... | 2008 | 18285492 |
| discovery of virulence factors of pathogenic bacteria. | discovering virulence factors of pathogenic bacteria is a key in understanding pathogenesis and for identification of targets for novel drugs and design of new vaccines. comparative genomics, transcriptomics, and proteomics have become the popular tools in discovering the virulence factors in bacterial pathogens, such as neisseria meningitidis, yersinia pestis, mycobacterium tuberculosis, and staphylococcus aureus. in addition, proteomics has been employed successfully in the study of the mechan ... | 2008 | 18284925 |
| the iron-responsive fur regulon in yersinia pestis. | the ferric uptake regulator (fur) is a predominant bacterial regulator controlling the iron assimilation functions in response to iron availability. our previous microarray analysis on yersinia pestis defined the iron-fur modulon. in the present work, we reannotated the iron assimilation genes in y. pestis, and the resulting genes in complementation with those disclosed by microarray constituted a total of 34 genome loci (putative operons) that represent the potential iron-responsive targets of ... | 2008 | 18281395 |
| structural characterization of the yersinia pestis type iii secretion system needle protein yscf in complex with its heterodimeric chaperone ysce/yscg. | the plague-causing bacterium yersinia pestis utilizes a type iii secretion system to deliver effector proteins into mammalian cells where they interfere with signal transduction pathways that mediate phagocytosis and the inflammatory response. effector proteins are injected through a hollow needle structure composed of the protein yscf. yscg and ysce act as "chaperones" to prevent premature polymerization of yscf in the cytosol of the bacterium prior to assembly of the needle. here, we report th ... | 2008 | 18281060 |
| insights into yersinia pestis biofilm development: topology and co-interaction of hms inner membrane proteins involved in exopolysaccharide production. | primarily, three operons, hmshfrs, hmst and hmsp, are responsible for the development of a yersinia pestis biofilm, which is essential for blockage-dependent transmission of plague from fleas to mammals. here, using specific antibodies, a polymeric beta-1,6-n-acetyl-d-glucosamine-like polysaccharide was detected in the extracellular matrix of hmshfrs-dependent y. pestis biofilm. the production of this exopolysaccharide (eps) was controlled by diguanylate cyclase hmst and eal domain phosphodieste ... | 2008 | 18279344 |
| [conservation of yersinia pestis in winter by citellophilus tesquorum altaicus females and males]. | intersexual differences have been established in citellophilus tesquorum altaicus ioff (1936) from a tuva natural focus in the accumulation of yersinia pestis in fleas in autumn and its conservation during winter. the ectoparasites were infected and fed on the natural feeder - long-tailed siberian souslik (citellus undulates). small wild animals and insects were infected with the strain yersinia pestis 1-3226 typical of the focus. in winter fleas survived without the feeder under artificially cr ... | 2007 | 18277419 |