Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| analysis of the sensitivity properties of a model of vector-borne bubonic plague. | model sensitivity is a key to evaluation of mathematical models in ecology and evolution, especially in complex models with numerous parameters. in this paper, we use some recently developed methods for sensitivity analysis to study the parameter sensitivity of a model of vector-borne bubonic plague in a rodent population proposed by keeling & gilligan. the new sensitivity tools are based on a variational analysis involving the adjoint equation. the new approach provides a relatively inexpensive ... | 2008 | 18270149 |
| vaccination with f1-v fusion protein protects black-footed ferrets (mustela nigripes) against plague upon oral challenge with yersinia pestis. | previous studies have established that vaccination of black-footed ferrets (mustela nigripes) with f1-v fusion protein by subcutaneous (sc) injection protects the animals against plague upon injection of the bacterium yersinia pestis. this study demonstrates that the f1-v antigen can also protect ferrets against plague contracted via ingestion of a y. pestis-infected mouse, a probable route for natural infection. eight black-footed ferret kits were vaccinated with f1-v protein by sc injection at ... | 2008 | 18263816 |
| lcrg secretion is not required for blocking of yops secretion in yersinia pestis. | lcrg, a negative regulator of the yersinia type iii secretion apparatus has been shown to be primarily a cytoplasmic protein, but is secreted at least in y. pestis. lcrg secretion has not been functionally analyzed and the relevance of lcrg secretion on lcrg function is unknown. | 2008 | 18261225 |
| plague reappearance in algeria after 50 years, 2003. | an outbreak of plague occurred in the region of oran, algeria, from june to july 2003. algeria had not reported this disease for >50 years. eighteen bubonic cases were identified, and yersinia pestis was isolated from 6 patients. except for the index case-patient, all patients recovered. targeted chemoprophylaxis, sanitation, and vector control played a crucial role in controlling the outbreak. epidemiologic and biomolecular findings strongly suggested the existence of a local animal reservoir d ... | 2007 | 18257987 |
| interaction between yersinia pestis and the host immune system. | 2008 | 18250178 | |
| different genes govern yersinia pestis pathogenicity in caenorhabditis elegans and human lice. | to assess the role of virulence factors identified in caenorhabditis elegans in the transmission of plague by lice, we infected 100 lice by feeding them on rabbits and made them bacteremic; the rabbits had been intravenously inoculated with 10(9) cfu of six different mutant yersinia pestis strains of lower pathogenicity for c. elegans, obtained from the kim5 strain. this strain lacks genes used for biofilm formation. high mortality rates were observed in all lice, which excreted viable bacteria ... | 2008 | 18248948 |
| fieldable genotyping of bacillus anthracis and yersinia pestis based on 25-loci multi locus vntr analysis. | anthrax and plague are diseases caused by bacillus anthracis and yersinia pestis respectively. these bacteria are etiological agents for worldwide zoonotic diseases and are considered among the most feared potential bioterror agents. strain differentiation is difficult for these microorganisms because of their high intraspecies genome homogeneity. moreover, fast strain identification and comparison with known genotypes may be crucial for naturally occurring outbreaks versus bioterrorist events d ... | 2008 | 18230125 |
| [selection of atypical rhamnose-positive strains of the basic yersinia pestis subspecies by conventional identification methods]. | 2007 | 18228660 | |
| membrane localization and topology of the yersinia pestis yscj lipoprotein. | the localization and membrane topology of the yersinia pestis yscj lipoprotein, an essential component of the type iii secretion apparatus, was investigated. yscj was demonstrated to be an inner membrane (im) lipoprotein that is anchored to the periplasmic face of the im via an n-terminal lipid moiety and via a c-terminal transmembrane (tm) domain. localization of the n-terminal lipid moiety to the im occurred regardless of the amino-acid residues found in the +2 or +3 positions. im localization ... | 2008 | 18227263 |
| capsular antigen fraction 1 and pla modulate the susceptibility of yersinia pestis to pulmonary antimicrobial peptides such as cathelicidin. | inhaled yersinia pestis produces a severe primary pneumonia known as pneumonic plague, which is contagious and highly lethal to humans and animals. in this study, we first determined the susceptibility of y. pestis kim6 to antimicrobial molecules of the airways. we found that (i) rat bronchoalveolar lavage fluid (rbalf) effectively killed kim6 cells growing at 37 degrees c; (ii) the antibacterial components of rbalf were small peptides (<10 kda) that included two cationic antimicrobial peptides ... | 2008 | 18227173 |
| braun lipoprotein (lpp) contributes to virulence of yersiniae: potential role of lpp in inducing bubonic and pneumonic plague. | yersinia pestis evolved from y. pseudotuberculosis to become the causative agent of bubonic and pneumonic plague. we identified a homolog of the salmonella enterica serovar typhimurium lipoprotein (lpp) gene in yersinia species and prepared lpp gene deletion mutants of y. pseudotuberculosis ypiii, y. pestis kim/d27 (pigmentation locus minus), and y. pestis co92 with reduced virulence. mice injected via the intraperitoneal route with 5 x 10(7) cfu of the deltalpp kim/d27 mutant survived a month, ... | 2008 | 18227160 |
| [the development of peroxosolvate-based composites and the evaluation of their effectiveness against extremely dangerous infective pathogens]. | the article contains the results of the test of pfk-m composition bactericidal activity against a range of extremely dangerous infective pathogens. the preparation proved to be highly effective for the disinfection of surfaces, sanitary and technical equipment, linen, dishes, and medical utensils contaminated by plague, cholera, and anthrax pathogens. the study found that the antimicrobial activity of the preparation increased after heating and lowered when the object to be disinfected was conta ... | 2007 | 18225504 |
| [indication of extremely dangerous infectious pathogens using immunochromatography and digital video analysis]. | the use of immunochromatographic indicatory elements based on antibody conjugates and colloidal gold was suggested to detect cells and the antigens of extremely dangerous infectious pathogens. the specificity and specific activity (sensitivity) of the mentioned elements were studied on vaccinal strains of plague, anthrax, and tularemia pathogens. the researchers studied a possibility to increase the sensitivity of immunochromatographic analysis using computed scanning and reflecom, a specialized ... | 2007 | 18225501 |
| plague: past, present, and future. | 2008 | 18198939 | |
| climate-driven spatial dynamics of plague among prairie dog colonies. | we present a bayesian hierarchical model for the joint spatial dynamics of a host-parasite system. the model was fitted to long-term data on regional plague dynamics and metapopulation dynamics of the black-tailed prairie dog, a declining keystone species of north american prairies. the rate of plague transmission between colonies increases with increasing precipitation, while the rate of infection from unknown sources decreases in response to hot weather. the mean annual dispersal distance of p ... | 2008 | 18197776 |
| structural requirements for yersinia yopj inhibition of map kinase pathways. | mapk signaling cascades are evolutionally conserved. the bacterial effector, yopj, uses the unique activity of ser/thr acetylation to inhibit the activation of the mapk kinase (mkk) and prevent activation by phosphorylation. yopj is also able to block yeast mapk signaling pathways using this mechanism. based on these observations, we performed a genetic screen to isolate mutants in the yeast mkk, pbs2, that suppress yopj inhibition. one suppressor contains a mutation in a conserved tyrosine resi ... | 2008 | 18167536 |
| yersinia pestis yopd 150-287 fragment is partially unfolded in the native state. | yersinia pestis, a human and animal pathogen, uses the type iii secretion system (t3ss) for delivering virulence factors and effectors into the host cells. the system is conserved in animal pathogens and is hypothesized to deliver the virulence factors directly from bacterial to mammalian cells through a pore composed of yopb and yopd translocation proteins. the yopb and yopd translocator proteins must be delivered first to form a functional pore in the mammalian cell. the criteria by which yers ... | 2008 | 18160307 |
| relationship of catalase activity to virulence in pasteurella pestis. | 1949 | 18145415 | |
| the behavior of pasteurella pestis in glycerin and rhamnose mediums. | 1949 | 18132375 | |
| twenty-five year survival of a pasteurella pestis culture without transfer. | 1949 | 18124445 | |
| alteration of pasteurella pestis bacteriophage following successive transfer on pasteurella pseudotuberculosis and on shigellae. | 1948 | 18102208 | |
| mutation adjacent to the active site tyrosine can enhance dna cleavage and cell killing by the toprim gly to ser mutant of bacterial topoisomerase i. | the toprim dxdxxg residues of type ia and ii topoisomerases are involved in mg(ii) binding and the cleavage-rejoining of dna. mutation of the strictly conserved glycine to serine in yersinia pestis and escherichia coli topoisomerase i results in bacterial cell killing due to inhibition of dna religation after dna cleavage. in this study, all other substitutions at the toprim glycine of y. pestis topoisomerase i were examined. while the gly to ala substitution allowed both dna cleavage and religa ... | 2008 | 18096618 |
| identifying b and t cell epitopes and studying humoral, mucosal and cellular immune responses of peptides derived from v antigen of yersinia pestis. | yersinia pestis is a gram negative bacterium which causes bubonic and pneumonic plague. out of the two protective antigens f1 and v as vaccine candidates, we focused our attention on v antigen as peptide-based immunogen. eleven peptides of varying lengths were synthesized for mapping major antigenic sites on v antigen. six peptides showed competition by three complimentary approaches (1) with anti-v sera, (2) with anti-peptide sera and (3) by direct binding assay. peptides which showed competiti ... | 2008 | 18096277 |
| antibody profiling in plague patients by protein microarray. | a protein microarray containing 144 known or putative virulence-related proteins of yersinia pestis was used to evaluate the antibody responses of plague patients. forty-two proteins were found to be expressed in vivo and antibodies against 14 of them were detected in all patients analyzed, providing potential candidates for novel protective antigens and novel serodiagnostic markers in y. pestis. moreover, the lack of antibody to lcrv in the five patients in focus f might be a challenge to our u ... | 2008 | 18093862 |
| [the complex plague--reconsiderations of an epidemic from the past]. | speculations have arisen about the black plague in recent years - was it a disease caused by yersinia pestis: or something else? extensive outbreaks in india in the 1890s have formed the basis for descriptions of the plague, both for those who believe that the medieval plagues and modern plague were different diseases and for those who claim that the plague has been one and the same disease throughout history. the plague was more or less defined as a disease in the 1890s, and the understanding o ... | 2007 | 18084387 |
| [was yersinia pestis the cause of the black death?]. | 2007 | 18084357 | |
| broad t cell immunity to the lcrv virulence protein is induced by targeted delivery to dec-205/cd205-positive mouse dendritic cells. | there is a need for a more efficient vaccine against the bacterium yersinia pestis, the agent of pneumonic plague. the f1-lcrv (f1-v) subunit vaccine in alhydrogel is known to induce humoral immunity. in this study, we utilized dc to investigate cellular immunity. we genetically engineered the lcrv virulence protein into the anti-dec-205/cd205 mab and thereby targeted the conjugated protein directly to mouse dec-205(+) dc in situ. we observed antigen-specific cd4(+) t cell immunity measured by i ... | 2008 | 18081041 |
| genome-wide in silico mapping of the secretome in pathogenic yersinia pestis kim. | uncovering the secretome of yersinia pestis is a necessary measure to better understand the virulence of this plague-causing bacterium. using bioinformatics methods, the components of all the secretion systems known to date in the y. pestis kim genome were mapped, including several systems identified by this study. it was found that this organism possesses sec, twin-arginine translocation, signal recognition particle, omp85/yaet, type i, type ii, type iii, type vi, chaperone/usher, autotransport ... | 2008 | 18070074 |
| molecular characterization of l-413c, a p2-related plague diagnostic bacteriophage. | our analysis of the plague diagnostic phage l-413c genome sequence and structure reveals that l-413c is highly similar and collinear with enterobacteriophage p2, though important differences were found. of special interest was the mosaic nature of the tail fiber protein h in l-413c, given the differentiating specificity of this phage for yersinia pestis vs. yersinia pseudotuberculosis. while the n-terminal 207 and c-terminal 137 amino acids of l-413c display significant homology with the p2 h pr ... | 2008 | 18045639 |
| [prophylactic use of ceftriaxone in combination with f i antigen immunization in studies on uninbred albino mice infected by yersinia pestis. antiplague immunity development]. | administration of highly immunogenic (ed50 12.6 mcg/mouse) f i antigen (100 mcg/mouse) to albino mice 5 hours after their contamination approximately with 1000 ld50 of yersinia pestis 231 provided 99-percent survival of same animals (17-50%) and 2-5-day prolongation of the life-span, that was indicative of the phenomenon analogous to the survival phenomenon observed in infected animals immunized by immunogenic strains of the plague microbe. the experiment on the mice confirmed high efficacy of c ... | 2006 | 18030785 |
| yersinia genome diversity disclosed by yersinia pestis genome-wide dna microarray. | the genus yersinia includes 11 species, 3 of which (y. pestis, y. pseudotuberculosis, and y. enterocolitica) are pathogenic for humans. the remaining 8 species (y. frederiksenii, y. intermedia, y. kristensenii, y. bercovieri, y. mollaretii, y. rohdei, y. ruckeri, and y. aldovae) are merely opportunistic pathogens found mostly in the environment. in this work, the genomic differences among yersinia were determined using a y. pestis-specific dna microarray. the results revealed 292 chromosomal gen ... | 2007 | 18026215 |
| analyzing patterns of microbial evolution using the mauve genome alignment system. | during the course of evolution, genomes can undergo large-scale mutation events such as rearrangement and lateral transfer. such mutations can result in significant variations in gene order and gene content among otherwise closely related organisms. the mauve genome alignment system can successfully identify such rearrangement and lateral transfer events in comparisons of multiple microbial genomes even under high levels of recombination. this chapter outlines the main features of mauve and prov ... | 2007 | 18025691 |
| resistance of yersinia pestis to complement-dependent killing is mediated by the ail outer membrane protein. | yersinia pestis, the causative agent of plague, must survive in blood in order to cause disease and to be transmitted from host to host by fleas. members of the ail/lom family of outer membrane proteins provide protection from complement-dependent killing for a number of pathogenic bacteria. the y. pestis kim genome is predicted to encode four ail/lom family proteins. y. pestis mutants specifically deficient in expression of each of these proteins were constructed using lambda red-mediated recom ... | 2008 | 18025094 |
| yadbc of yersinia pestis, a new virulence determinant for bubonic plague. | in all yersinia pestis strains examined, the adhesin/invasin yada gene is a pseudogene, yet y. pestis is invasive for epithelial cells. to identify potential surface proteins that are structurally and functionally similar to yada, we searched the y. pestis genome for open reading frames with homology to yada and found three: the bicistronic operon yadbc (ypo1387 and ypo1388 of y. pestis co92; y2786 and y2785 of y. pestis kim5), which encodes two putative surface proteins, and ypo0902, which lack ... | 2008 | 18025093 |
| structures of oppa and psts from yersinia pestis indicate variability of interactions with transmembrane domains. | bacterial atp-binding cassette (abc) transport systems couple atp hydrolysis with the uptake and efflux of a wide range of substances across bacterial membranes. these systems are comprised of transmembrane domains, nucleotide binding domains and, in the case of uptake systems, periplasmic binding proteins responsible for binding and presentation of substrate to the transmembrane domains. in pathogenic bacteria, abc systems are known to play roles in virulence and pathogenicity and the surface l ... | 2007 | 18007034 |
| structure and activity of yersinia pestis 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase as a novel target for the development of antiplague therapeutics. | 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase (hppk) is a key enzyme in the folate-biosynthetic pathway and is essential for microorganisms but absent from mammals. hppk catalyzes mg(2+)-dependent pyrophosphoryl transfer from atp to 6-hydroxymethyl-7,8-dihydropterin (hp). previously, three-dimensional structures of escherichia coli hppk (echppk) have been determined at almost every stage of its catalytic cycle and the reaction mechanism has been established. here, the crystal structure of ... | 2007 | 18007032 |
| enteropathogen resource integration center (eric): bioinformatics support for research on biodefense-relevant enterobacteria. | eric, the enteropathogen resource integration center (www.ericbrc.org), is a new web portal serving as a rich source of information about enterobacteria on the niaid established list of select agents related to biodefense-diarrheagenic escherichia coli, shigella spp., salmonella spp., yersinia enterocolitica and yersinia pestis. more than 30 genomes have been completely sequenced, many more exist in draft form and additional projects are underway. these organisms are increasingly the focus of st ... | 2008 | 17999997 |
| ultraviolet inactivation kinetics of escherichia coli and yersinia pseudotuberculosis in annular reactors. | terrorist threats have precipitated the need for information on the ultraviolet (uv) resistance of potential biothreat agents in food processing, such as yersinia pestis. the objective of this study was to characterize the resistance of the yersinia species to uv treatment using a single-lamp annular uv reactor. a novel method is proposed to measure the inactivation kinetics of yersinia pseudotuberculosis, a surrogate of y. pestis. this proposed method can overcome the disadvantages of the tradi ... | 2007 | 17995726 |
| [mission oriented diagnostic real-time pcr]. | in out of area military missions soldiers are potentially exposed to bacteria that are endemic in tropical areas and can be used as biological agents. it can be difficult to culture these bacteria due to sample contamination, low number of bacteria or pretreatment with antibiotics. commercial biochemical identification systems are not optimized for these agents which can result in misidentification. immunological assays are often not commercially available or not specific. real-time pcr assays a ... | 2007 | 17987355 |
| characterization of integrative and conjugative element icekp1-associated genomic heterogeneity in a klebsiella pneumoniae strain isolated from a primary liver abscess. | genomic heterogeneity has been shown to be associated with klebsiella pneumoniae strains causing pyogenic liver abscesses (pla) and metastatic infections. in order to explore the mechanism responsible for genomic heterogeneity in k. pneumoniae, we compared the complete genomic sequences of strains ntuh-k2044 and mgh78578. an approximately 76-kbp dna fragment located adjacent to an asparagine (asn) trna gene was present in ntuh-k2044 but not in mgh78578. this fragment could be divided into three ... | 2008 | 17981959 |
| substrate specificity and screening of the integral membrane protease pla. | this paper reports a study to find small peptide substrates for the important virulence factor of yersinia pestis, plasminogen activator, pla. the method used to find small substrates for this protease is reported along with studies examining the ability of these peptides to inhibit activity of the enzyme. through the use of parallel synthesis and positional scanning, small tripeptides were identified that are viable substrates for the protease. | 2008 | 17981463 |
| legionella pneumophila exhibits plasminogen activator activity. | based on their localization at the boundary of the bacterial cell and its environment, outer-membrane proteins (omps) are important determinants for interaction of bacteria with their host cell. therefore, they can be considered as important determinants for virulence. looking for legionella pneumophila omps potentially involved in virulence, we identified a gene encoding a homologue of the plasminogen activator (pla) of yersinia pestis. pla belongs to the class of omptins, a family of surface p ... | 2007 | 17975084 |
| protective immunity against plague. | plague, an infectious disease that reached catastrophic proportions during three pandemics, continues to be a legitimate public health concern worldwide. although antibiotic therapy for the causative agent yersinia pestis is available, pharmaceutical supply limitations, multi-drug resistance from natural selection as well as malicious bioengineering are a reality. consequently, plague vaccinology is a priority for biodefense research. development of a multi-subunit vaccine with fraction 1 and lc ... | 2007 | 17966437 |
| yersinia pestis yadc: a novel vaccine candidate against plague. | current subunit vaccines provide partial protection against pneumonic plague if the infecting y. pestis strain is encapsulated (f1+). here we describe yadc, a novel y. pestis outer membrane protein that provides partial protection against a f1(-) y. pestis strain. swiss-webster mice were immunized subcutaneously with glutathione s-transferase (gst) or his6-tagged (ht) purified fusion proteins (gst-yadc137-409 or ht-lcrv) or buffer emulsified with alhydrogel. intravenous challenge with 1 x 10(4) ... | 2007 | 17966436 |
| oral vaccination with different antigens from yersinia pestis kim delivered by live attenuated salmonella typhimurium elicits a protective immune response against plague. | the use of live recombinant salmonella attenuated vaccine (rasv) encoding yersinia proteins is a promising new approach for the vaccination against yersinia pestis. we have tested the efficacy of 2 proteins, psn and a portion of lcrv in protecting mice against virulent yersinia pestis challenge. to remove the immunosuppressive properties of lcrv protein, the lcrv gene, without the tlr2 receptor sequence, was cloned into a beta-lactamase secretion vector. immunizations were performed with rsav ex ... | 2007 | 17966435 |
| cell-mediated defense against yersinia pestis infection. | yersinia pestis (yp)--one of the world's most deadly human pathogens--is the gram-negative bacterium that causes pneumonic plague. virulent antibiotic-resistant yp strains exist and cold war scientists devised means to effectively aerosolize yp. these facts raise grave concern that yp will be exploited as a bioweapon. to counter that possibility, it is essential that we develop a safe and effective pneumonic plague vaccine. recent studies suggest that the leading vaccine candidate, which primari ... | 2007 | 17966434 |
| high throughput screening for small-molecule inhibitors of type iii secretion in yersinia pestis. | yersinia pestis, yersinia pseudotuberculosis and yersinia enterocolitica, utilize a plasmid encoded type iii secretion system (t3ss) to promote infection by delivering yersinia outer proteins (yops) into the cytosol of mammalian cells. this t3ss is absolutely required for yersinia virulence, which makes t3ss an attractive target in the development of novel therapeutics for treatment of plague and other yersinia infections. in this study, a new method for high throughput screening (hts) of small ... | 2007 | 17966433 |
| development and evaluation of a single tube nested pcr based approach (stnpcr) for the diagnosis of plague. | the performance of a single-tube nested-pcr (stnpcr) technique was evaluated for plague diagnosis in comparison to conventional (one step) and two step nested pcr (npcr). assays were carried out with primers targeting the gene caf1 that encodes the yersinia pestis f1 antigen. for stnpcr inner primers were immobilized onto the inside of the microtube caps and after the first amplification they were eluted by inversion of the tube. this procedure avoids opening the tube, reducing the risks of fals ... | 2007 | 17966431 |
| enrichment of yersinia pestis from blood cultures enables rapid antimicrobial susceptibility determination by flow cytometry. | mortality from plague is high if not treated with the proper antibiotics within 18-24 hours after onset of symptoms. the process of antibiotic susceptibility determination of yersinia pestis isolated from blood samples may extend from 4 to more than 7 days, since the in vitro growth is very slow. to accelerate this process, we developed an enrichment protocol as well as a non-standard yet reliable method for rapid antibiotic susceptibility analysis of y. pestis from blood cultures using flow cyt ... | 2007 | 17966430 |
| analysis of the three yersinia pestis crispr loci provides new tools for phylogenetic studies and possibly for the investigation of ancient dna. | the precise nature of the pathogen having caused early plague pandemics is uncertain. although yersinia pestis is a likely candidate for all three plague pandemics, the very rare direct evidence that can be deduced from ancient dna (adna) analysis is controversial. moreover, which of the three biovars, antiqua, medievalis or orientalis, was associated with these pandemics is still debated. there is a need for phylogenetic analysis performed on y. pestis strains isolated from countries from which ... | 2007 | 17966429 |
| 3 is-rflp: a powerful tool for geographical clustering of global isolates of yersinia pestis. | multiple copies of several classes of insertion sequences (is) are found in the genome of yersinia pestis, the causative agent of bubonic and pneumonic plague. we used the genetic instability generated by these is to develop a method (designated 3is-rflp) based on the restriction fragment length polymorphism of the is100, is285 and is1541 elements for studying y. pestis strains of worldwide origin. we show that 31s-rflp is a powerful tool to group y. pestis isolates according to their geographic ... | 2007 | 17966428 |
| disparity between yersinia pestis and yersinia enterocolitica o:8 in yopj/yopp-dependent functions. | yopp in y. enterocolitica and yopj in y. pseudotuberculosis, have been shown to exert a variety of adverse effects on cell signaling leading to suppression of cytokine expression and induction of programmed cell death. a comparative in vitro study with y. pestis and y. enterocolitica o:8 virulent strains shows some critical disparity in yopj/yopp-related effects on immune cells. involvement of yopj in virulence was evaluated in mouse model of bubonic plague. | 2007 | 17966427 |
| a rationale for repression and/or loss of motility by pathogenic yersinia in the mammalian host. | pathogenic yersiniae either repress flagella expression under host conditions (yersinia enterocolitica and yersinia pseudotuberculosis) or have permanently lost this capability by mutation (yersinia pestis). the block in flagella synthesis for the enteropathogenic yersinia centers on flia (sigmaf) repression. this repression ensures the downstream repression of flagellin structural genes which can be cross-recognized and secreted by virulence type iii secretion systems. y. pestis carries several ... | 2007 | 17966426 |
| using every trick in the book: the pla surface protease of yersinia pestis. | the pla surface protease of yersinia pestis, encoded by the y. pestis-specific plasmid ppcp1, is a versatile virulence factor. in vivo studies have shown that pla is essential in the establishment of bubonic plague, and in vitro studies have demonstrated various putative virulence functions for the pla molecule. pla is a surface protease of the omptin family, and its proteolytic targets include the abundant, circulating human zymogen plasminogen, which is activated by pla to the serine protease ... | 2007 | 17966423 |
| the insect toxin complex of yersinia. | many members of the yersinia genus encode homologues of insect toxins first observed in bacteria that are insect pathogens such as photorhabdus, xenorhabdus and serratia entomophila. these bacteria secrete high molecular weight insecticidal toxins comprised of multiple protein subunits, termed the toxin complexes or tc's. in photorhabdus three distinct tc subunits are required for full oral toxicity in insects, that include the [a], [b] and [c] types, although the exact stochiometry remains uncl ... | 2007 | 17966421 |
| identification of tyea residues required to interact with yopn and to regulate yop secretion. | the secretion of yops via the yersinia type iii secretion system (t3ss) is controlled, in part, by a cytoplasmic yopn/tyea complex. this complex is required to prevent yop secretion in the presence of extracellular calcium and prior to contact between the bacterium and a eukaryotic cell. in this study we utilized site-directed mutagenesis to analyze the role of specific tyea regions and residues in the regulation of yop secretion. we identified two spatially distinct, surface-exposed regions of ... | 2007 | 17966420 |
| roles of yopn, lcrg and lcrv in controlling yops secretion by yersinia pestis. | control of yops secretion in pathogenic yersinia is achieved at several levels. these levels likely include transcriptional, post-transcriptional, translational and secretional controls. secretion control appears to be mediated by two pathways. one pathway involves yopn and proteins that interact with yopn. the second pathway consists of lcrg and its interaction with lcrv. lcrv is a postive regulator of yops secretion that exerts control over yops secretion by negating the secretion blocking rol ... | 2007 | 17966419 |
| regulation of biofilm formation in yersinia pestis. | plague biofilm development is controlled by positive (hmst) and negative (hmsp) regulators. the ggdef-domain protein hmst appears to have diguanylate cyclase activity to synthesize bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-gmp) from 2 gtp molecules. the eal domain of hmsp has phosphodiesterase activity and likely degrades c-di-gmp. this second messenger molecule probably influences biofilm development by activating the glycosyl transferase activity of hmsr. here we demonstrate the ... | 2007 | 17966416 |
| analysis of yersinia pestis gene expression in the flea vector. | yersinia pestis is the causative agent of plague. unlike the other pathogenic yersinia species, y. pestis has evolved an arthropod-borne route of transmission, alternately infecting flea and mammalian hosts. distinct subsets of genes are hypothesized to be differentially expressed during infection of the arthropod vector and mammalian host. genes crucial for mammalian infection are referred to as virulence factors whilst genes playing a role in the flea vector are termed transmission factors. th ... | 2007 | 17966415 |
| functional quorum sensing systems affect biofilm formation and protein expression in yersinia pestis. | gram-negative bacteria predominantly use two types of quorum sensing (qs) systems--luxi-luxr, responsible for synthesis of n-acylhomoserine lactones (ahl or ai-1 signal molecule), and luxs, which makes furanones (ai-2 signal molecule). we showed that luxs and two luxi-luxr (ytbir and ypsir) systems are functional in y. pestis. four different ahl molecules were detected in y. pestis extracts using tlc bioassays. our data suggest that ytbir is responsible for the production of long chain ahls. con ... | 2007 | 17966414 |
| differential gene regulation in yersinia pestis versus yersinia pseudotuberculosis: effects of hypoxia and potential role of a plasmid regulator. | the molecular basis of the biological differences between yersinia pestis and yersinia pseudotuberculosis remains largely unknown, and relatively little is known about environmental regulation of gene expression in these bacteria. we used a proteomic approach to explore the regulatory response of each bacterium to carbon dioxide-supplemented hypoxic conditions. both organisms responded similarly and the magnitude of their responses was similar to what was observed in low iron conditions. we also ... | 2007 | 17966410 |
| intermediary metabolism, na+, the low calcium-response, and acute disease. | the variables carriage of pcd, co2 tension, exogenous atp, l-glutamate, mg2+, na+, ph, source of energy, and temperature are known to modulate the low calcium response of yersinia pestis in vitro. the role of these effectors and the basis of their interactions are defined here with emphasis on known y. pestis-specific missense mutations in glucose 6-phosphate dehydrogenase and aspartase, which preclude use of the hexose monophosphate pathway and prevent efficient catabolism of l-glutamic acid, r ... | 2007 | 17966409 |
| polyamines in bacteria: pleiotropic effects yet specific mechanisms. | extensive data in a wide range of organisms point to the importance of polyamine homeostasis for growth. the two most common polyamines found in bacteria are putrescine and spermidine. the investigation of polyamine function in bacteria has revealed that they are involved in a number of functions other than growth, which include incorporation into the cell wall and biosynthesis of siderophores. they are also important in acid resistance and can act as a free radical ion scavenger. more recently ... | 2007 | 17966408 |
| characterization of six novel chaperone/usher systems in yersinia pestis. | 2007 | 17966407 | |
| relationship of the lipopolysaccharide structure of yersinia pestis to resistance to antimicrobial factors. | disruption of lipopolysaccharide (lps) biosynthesis genes in an epidemiologically significant yersinia pestis strain showed that the ability to synthesize the full inner core of the lps is crucial for resistances to the bactericidal action of antimicrobial peptides and to complement-mediated serum killing. resistance to polymyxin b also requires a high content of the cationic sugar, 4-amino-4-deoxy-l-arabinose, in lipid a. | 2007 | 17966406 |
| structure and assembly of yersinia pestis f1 antigen. | most gram negative pathogens express surface located fibrillar organelles that are used for adhesion to host epithelia and/or for protection. the assembly of many such organelles is managed by a highly conserved periplasmic chaperone/usher assembly pathway. during the last few years, considerable progress has been made in understanding how periplasmic chaperones mediate folding, targeting, and assembly of f1 antigen subunits into the f1 capsular antigen. in particular, structures representing sn ... | 2007 | 17966405 |
| my life with yersinia. | this review is based on the opening lecture i was honored to give during the 9th international symposium on yersinia in lexington, kentucky in october 2006. i present some topics that have been close to my interest during the past 25 years with some historical anecdotes. for example, how detection of intervening sequences in yersinia enterocolitica rdna genes resulted in development of microbial diagnostic applications. how the adhesin yada was detected and named and what do we know of its funct ... | 2007 | 17966404 |
| a new asset for pathogen informatics--the enteropathogen resource integration center (eric), an niaid bioinformatics resource center for biodefense and emerging/re-emerging infectious disease. | eric (enteropathogen resource information center) is one of the national institute of allergy and infectious diseases (niaid) bioinformatics resource centers for biodefense and emerging/re-emerging infectious disease. eric serves as a comprehensive information resource for five related pathogens: yersinia enterocolitica, yersinia pestis, diarrheagenic e. coli, shigella spp., and salmonella spp. eric integrates genomics, proteomics, biochemical and microbiological information to facilitate the in ... | 2007 | 17966403 |
| variability of the protein sequences of lcrv between epidemic and atypical rhamnose-positive strains of yersinia pestis. | sequencing of lcrv genes and comparison of the deduced amino acid sequences from ten y. pestis strains belonging mostly to the group of atypical rhamnose-positive isolates (non-pestis subspecies or pestoides group) showed that the lcrv proteins analyzed could be classified into five sequence types. this classification was based on major amino acid polymorphisms among lcrv proteins in the four "hot points" of the protein sequences. some additional minor polymorphisms were found throughout these s ... | 2007 | 17966402 |
| pestoides f, an atypical yersinia pestis strain from the former soviet union. | unlike the classical yersinia pestis strains, members of an atypical group of y. pestis from central asia, denominated y. pestis subspecies caucasica (also known as one of several pestoides types), are distinguished by a number of characteristics including their ability to ferment rhamnose and melibiose, their lack of the small plasmid encoding the plasminogen activator (pla) and pesticin, and their exceptionally large variants of the virulence plasmid pmt (encoding murine toxin and capsular ant ... | 2007 | 17966401 |
| comparative transcriptomics in yersinia pestis: a global view of environmental modulation of gene expression. | environmental modulation of gene expression in yersinia pestis is critical for its life style and pathogenesis. using cdna microarray technology, we have analyzed the global gene expression of this deadly pathogen when grown under different stress conditions in vitro. | 2007 | 17963531 |
| direct transcriptional control of the plasminogen activator gene of yersinia pestis by the cyclic amp receptor protein. | horizontal gene transfer events followed by proper regulatory integration of a gene drive rapid evolution of bacterial pathogens. a key event in the evolution of the highly virulent plague bacterium yersinia pestis was the acquisition of plasmid ppcp1, which carries the plasminogen activator gene, pla. this promoted the bubonic form of the disease by increasing bacterial dissemination from flea bite sites and incidentally enhanced replication in respiratory airways during pneumonic infection. we ... | 2007 | 17933899 |
| tentacle probes: differentiation of difficult single-nucleotide polymorphisms and deletions by presence or absence of a signal in real-time pcr. | false-positive results are a common problem in real-time pcr identification of dna sequences that differ from near neighbors by a single-nucleotide polymorphism (snp) or deletion. because of a lack of sufficient probe specificity, post-pcr analysis, such as a melting curve, is often required for mutation differentiation. | 2007 | 17932130 |
| the elusive activity of the yersinia protein kinase a kinase domain is revealed. | yersinia spp. pathogens use their type iii secretion system to translocate effectors that manipulate host signaling pathways during infection. although molecular targets for five of the six known yersinia effectors are known, the target for the serine/threonine kinase domain of yersinia protein kinase a (ypka) has remained elusive. recently, navarro et al. (2007) demonstrated that ypka phosphorylates galphaq, and inhibits galphaq-mediated signaling. inhibition by ypka could contribute to one of ... | 2007 | 17920275 |
| [approaches to species-specific typing of double mixed cultures comprising pseudotuberculosis bacteria and atypical plague bacillus strains]. | the species relevance of atypical yersinia strains was determined by various microbiological, immunological, and genetic (including polymerase chain reaction) tests. these strains were shown to represent mixed cultures of y. pseudotuberculosis serovariant o1b and y. pestis var antiqua. identification-resistant cells with atypical properties and plasmid segregation were found in the populations of y. pestis strains. analysis of different diagnostic tests revealed the most reliable ones selected f ... | 2007 | 17915487 |
| a yersinia pestis lpxm-mutant live vaccine induces enhanced immunity against bubonic plague in mice and guinea pigs. | the lpxm mutant of the live vaccine yersinia pestis ev niieg strain synthesising a less toxic penta-acylated lipopolysaccharide was found to be avirulent in mice and guinea pigs, notably showing no measurable virulence in balb/c mice which do retain some susceptibility to the parental strain itself. twenty-one days after a single injection of the lpxm-mutant, 85-100% protection was achieved in outbred mice and guinea pigs, whereas a 43% protection rate was achieved in balb/c mice given single lo ... | 2007 | 17913308 |
| prompt laboratory diagnosis in timely containment of a plague outbreak in india. | a focal outbreak of pneumonic plague occurred in a hamlet of village hatkoti, district shimla, himachal pradesh in the first fortnight of february, 2002. a total of 16 cases with 4 deaths were reported. diagnosis of plague was confirmed by the laboratory in 10 (63%) cases. y. pestis was isolated from clinical samples of 3 cases and confirmed by bacteriophage lysis. molecular tests confirmed the presence of y. pestis specific pla and f1 genes in 4 cases; dna fingerprinting had identity with the k ... | 2006 | 17913207 |
| [a rapid diagnostic test for plague detects yersinia pestis f1 antigen in ancient human remains]. | a rapid diagnostic dipstick test (rdt) that detects yersinia pestis f1 antigen has been recently applied on 18 putative plague victims exhumed from four archaeological burial sites in southeastern france dating back to the 16(th), 17(th) and 18(th) centuries. the y. pestis antigen f1 was detected in 12 ancient samples out of 18 (67%). negative controls confirmed their negativity (100%). our results emphasize that the detection threshold of the rdt for plague (0.5 ng/ml) is sufficient for a first ... | 2007 | 17905394 |
| activation of pro-matrix metalloproteinase-9 and degradation of gelatin by the surface protease pgte of salmonella enterica serovar typhimurium. | mammalian matrix metalloproteinases (mmps) degrade collagen networks in extracellular matrices by cleaving collagen and its denatured form gelatin, and thus enhance migration of mammalian cells. the gastrointestinal pathogen salmonella enterica survives and grows within host macrophages and dendritic cells, and can disseminate in the host by travelling within infected host cells. here, we report that s. enterica serovar typhimurium activates prommp-9 (gelatinase b) secreted by human primary macr ... | 2008 | 17888724 |
| protection against lethal subcutaneous challenge of virulent y. pestis strain 141 using an f1-v subunit vaccine. | in this study, we designed and engineered a two-component recombinant fusion protein antigen as a vaccine candidate against the possible biological threat of yersinia pestis. the recombinant f1-v protein was formulated with alhydrogel. a four-time injection with a dosage of 10, 20 and 50 microg/mouse in about two months was adopted for vaccination. serum antibodies and subclass of t helper cells were measured and analyzed. after the final vaccination, the mice were challenged by 141 strain with ... | 2007 | 17879056 |
| [study on the application and evaluation of methods for gene and antigen detection in plague surveillance program]. | to apply and evaluate new methods regarding specific gene and antigen detection in plague surveillance program. | 2007 | 17877166 |
| concomitant administration of yersinia pestis specific monoclonal antibodies with plague vaccine has a detrimental effect on vaccine mediated immunity. | antibodies can be used to confer rapid immunity against infectious agents for short periods of time. by comparison, vaccine induced immunity is more protective, but takes a relatively long time to develop. concomitant administration of antibody and vaccine by different routes was evaluated as a means of providing both rapid and long-term protection against plague. balb/c mice were treated intraperitoneally with monoclonal antibodies, with specificities for yersinia pestis lcrv and f1 antigens. a ... | 2007 | 17869388 |
| fibrinolysis and host response in bacterial infections. | the plasminogen activation system is part of the fibrinolysis which is tightly regulated and protected against dysfunction by various activators and inhibitors. however, microorganisms including bacteria, fungi and also parasites have been proven to interact in a specific manner with components of the fibrinolytic pathways. pathogenic bacteria are capable to subvert the function of proteases, activators or inhibitors for their own benefits including dissemination within the host and evasion of h ... | 2007 | 17849039 |
| pasteurella pestis: role of pesticin i and iron in experimental plague. | loss of the genetic determinant for pesticin i in pasteurella pestis results in concomitant loss of the plague coagulase and fibrinolytic factor. the median lethal dose for mice of an isolate lacking only these activities is increased by factors of about 10(1), 10(4), and 10(7) cells when administered by the intravenous, intraperitoneal, and subcutaneous routes, respectively. virulence of the aforesaid strain can be enhanced in mice treated with 40 microg of ferrous iron. this response resembles ... | 1965 | 17809405 |
| the rova regulons of yersinia enterocolitica and yersinia pestis are distinct: evidence that many rova-regulated genes were acquired more recently than the core genome. | rova is a transcriptional activator of yersinia invasin, an outer membrane protein involved in bacterial attachment and invasion across the intestinal epithelium. in y. enterocolitica, a rova mutant is attenuated for virulence compared with either wild-type or inv mutant strains, indicating that rova may regulate additional virulence factors. here, we used microarray analysis to define the rova regulon. curiously, there was little overlap between the rova regulons of y. enterocolitica and y. pes ... | 2007 | 17784909 |
| the complete genome sequence of yersinia pseudotuberculosis ip31758, the causative agent of far east scarlet-like fever. | the first reported far east scarlet-like fever (feslf) epidemic swept the pacific coastal region of russia in the late 1950s. symptoms of the severe infection included erythematous skin rash and desquamation, exanthema, hyperhemic tongue, and a toxic shock syndrome. the term feslf was coined for the infection because it shares clinical presentations with scarlet fever caused by group a streptococci. the causative agent was later identified as yersinia pseudotuberculosis, although the range of mo ... | 2007 | 17784789 |
| transcriptome analysis of yersinia pestis in human plasma: an approach for discovering bacterial genes involved in septicaemic plague. | yersinia pestis is the aetiologic agent of plague. without appropriate treatment, the pathogen rapidly causes septicaemia, the terminal and fatal phase of the disease. in order to identify bacterial genes which are essential during septicaemic plague in humans, we performed a transcriptome analysis on the fully virulent y. pestis co92 strain grown in either decomplemented human plasma or luria-bertani medium, incubated at either 28 or 37 degrees c and harvested at either the mid-exponential or t ... | 2007 | 17768254 |
| phenotypic characterization of ompx, an ail homologue of yersinia pestis kim. | the goal of this study was to characterize the yersinia pestis kim ompx protein. yersinia spp. provide a model for studying several virulence processes including attachment to, and internalization by, host cells. for yersinia enterocolitica and yersinia pseudotuberculosis, ail, yada and inv, have been implicated in these processes. in y. pestis, yada and inv are inactivated. genomic analysis of two y. pestis strains revealed four loci with sequence homology to ail. one of these genes, designated ... | 2007 | 17768237 |
| kinetic analysis of yersinia pestis dna adenine methyltransferase activity using a hemimethylated molecular break light oligonucleotide. | dna adenine methylation plays an important role in several critical bacterial processes including mismatch repair, the timing of dna replication and the transcriptional control of gene expression. the dependence of bacterial virulence on dna adenine methyltransferase (dam) has led to the proposal that selective dam inhibitors might function as broad spectrum antibiotics. | 2007 | 17726531 |
| [dispersal of the flea ctenophyllus hirticrus and spreading of plague epizooties in gorny altai]. | gradual dispersion of an abundant flea species ctenophyllus hirticrus specific to the pallas's pika (the main plague carrier), is revealed in the gorno-altai natural plague focus on the territory, occupied by two populations of this lagomorph. spreading of yersinia pestis in these areas took place a short time later the rise of this ectoparasite's abundance. it is supposed that the colonization of these areas by c. hirticrus was one of the factors determined epizooties spreading within the focus ... | 2007 | 17722641 |
| development of quantitative real-time pcr assays for detection and quantification of surrogate biological warfare agents in building debris and leachate. | evaluation of the fate and transport of biological warfare (bw) agents in landfills requires the development of specific and sensitive detection assays. the objective of the current study was to develop and validate sybr green quantitative real-time pcr (q-pcr) assays for the specific detection and quantification of surrogate bw agents in synthetic building debris (sbd) and leachate. bacillus atrophaeus (vegetative cells and spores) and serratia marcescens were used as surrogates for bacillus an ... | 2007 | 17720820 |
| yersinia pestis evolution on a small timescale: comparison of whole genome sequences from north america. | yersinia pestis, the etiologic agent of plague, was responsible for several devastating epidemics throughout history and is currently of global importance to current public heath and biodefense efforts. y. pestis is widespread in the western united states. because y. pestis was first introduced to this region just over 100 years ago, there has been little time for genetic diversity to accumulate. recent studies based upon single nucleotide polymorphisms have begun to quantify the genetic diversi ... | 2007 | 17712418 |
| omptin proteins: an expanding family of outer membrane proteases in gram-negative enterobacteriaceae. | the escherichia coli k-12 outer membrane protein ompt is a prototype of a unique family of bacterial endopeptidases known as the omptins. this family includes ompt and ompp of e. coli, sopa of shigella flexneri, pgte of salmonella enterica, and pla of yersinia pestis. despite their sequence similarities, the omptins vary in their reported functions. the ompt protease is characterized by narrow cleavage specificity defined by the extracellular loops of the beta-barrel protruding above the lipid b ... | 2007 | 17710644 |
| modulation of dendritic cell differentiation and function by yopj of yersinia pestis. | yersinia pestis evades immune responses in part by injecting into host immune cells several effector proteins called yersinia outer proteins (yops) that impair cellular function. this has been best characterized in the innate effector cells, but much less so for cells involved in adaptive immune responses. dendritic cells (dc) sit at the crossroads between innate and adaptive immunity, and can function to initiate or inhibit adaptive immune responses. although y. pestis can target and inactivate ... | 2007 | 17705129 |
| the potential role of swift foxes (vulpes velox) and their fleas in plague outbreaks in prairie dogs. | swift foxes (vulpes velox) have been proposed as potential carriers of fleas infected with the bacterium yersinia pestis between areas of epizootics in black-tailed prairie dogs (cynomys ludovicianus). we examined antibody prevalence rates of a population of swift foxes in colorado, usa, and used polymerase chain reaction (pcr) assays to examine their flea biota for evidence of y. pestis. fifteen of 61 (24%) captured foxes were seropositive, and antibody prevalence was spatially correlated with ... | 2007 | 17699080 |
| modeling plague persistence in host-vector communities in california. | plague is an enzootic disease in the western united states, even though long-term persistent infections do not seem to occur. enzootic persistence may occur as a function of dynamic interactions between flea vectors and transiently infected hosts, but the specific levels of vector competence, host competence, and transmission and recovery rates that would promote persistence and emergence among wild hosts and vectors are not known. we developed a mathematical model of enzootic plague in the west ... | 2007 | 17699079 |
| function and molecular architecture of the yersinia injectisome tip complex. | by quantitative immunoblot analyses and scanning transmission electron microscopy (stem), we determined that the needle of the yersinia enterocolitica e40 injectisome consists of 139 +/- 19 yscf subunits and that the tip complex is formed by three to five lcrv monomers. a pentamer represented the best fit for an atomic model of this complex. the n-terminal globular domain of lcrv forms the base of the tip complex, while the central globular domain forms the head. hybrids between lcrv and its ort ... | 2007 | 17697254 |
| prediction of antigenically active regions in the ompf-like porin of yersinia pseudotuberculosis. | 2007 | 17695318 | |
| early-phase transmission of yersinia pestis by unblocked xenopsylla cheopis (siphonaptera: pulicidae) is as efficient as transmission by blocked fleas. | for almost a century, the oriental rat flea, xenopsylla cheopis (rothschild) (siphonaptera: pulicidae), was thought to be the most efficient vector of the plague bacterium yersinia pestis (yersin). approximately 2 wk after consuming an infectious bloodmeal, a blockage often forms in the flea's proventriculus, which forces the flea to increase its biting frequency and consequently increases the likelihood of transmission. however, if fleas remain blocked and continue to feed, they usually die wit ... | 2007 | 17695025 |
| temporal dynamics of early-phase transmission of yersinia pestis by unblocked fleas: secondary infectious feeds prolong efficient transmission by oropsylla montana (siphonaptera: ceratophyllidae). | plague, a flea-borne zoonotic disease, is characterized by rapidly spreading epizootics. rate of infectious spread is thought to be related to daily biting rate of the vector, the extrinsic incubation period, vector efficiency, and the duration of infectivity. a recent study of oropsylla montana (baker) (siphonaptera: ceratophyllidae), the primary vector of yersinia pestis (yersin) to humans in north america, revealed that this flea feeds readily on a daily basis, has a very short extrinsic incu ... | 2007 | 17695024 |