Publications

TitleAbstractYear(sorted descending)
Filter
PMID
Filter
[the presence of antibodies against francisella tularensis among inhabitants of north-eastern poland].in this work we analysed the frequency of incidence of antibodies against f. tularensis among forest workers in region of north-eastern poland. the presence was detected in 0,13% analised workers and 3,38% hospitalised patients in clinic of parasitic diseases and neuroinfections in białystok.19968711161
tick-borne illness increasing in oklahoma. 19968720556
lack of requirement for prolonged incubation of septi-chek blood culture bottles in patients with bacteremia due to fastidious bacteria.a questionnaire survey for which there were 538 respondents from american clinical microbiology laboratories was used to assess the need for prolonged incubation of septi-chek blood culture bottles for the recovery of hacek bacilli, brucella species, francisella tularensis, and nutritionally deficient streptococci from blood. among a total of 219 reported isolates of these bacteria, in only 6 cases (2.7%) was incubation longer than 7 days required. only 2 of 136 patients (1.5%) were noted to be ...19968724399
minimal requirements for murine resistance to infection with francisella tularensis lvs.intraperitoneal or intravenous infection of mice with francisella tularensis lvs is lethal, with an intraperitoneal 50% lethal dose (ld50) approaching a single bacterium. intradermal (i.d.) lvs infection has a much higher ld50, about 10(6) bacteria in balb/cbyj mice, and survival of i.d. infection leads to solid generation of immunity against lethal challenge. to define the minimal requirements for both initial and long-term survival of i.d. infection, we characterized the nature of i.d. lvs inf ...19968757866
tularemia in a dog.a 13-month-old german shepherd dog was presented with acute onset of anorexia, pyrexia, lymphadenopathy, and tonsillitis. tularemia was diagnosed based on a greater-than-fourfold increase in antifrancisella tularensis antibody titers over a three-week period. the disease was self-limiting, and clinical signs resolved within five days with only supportive therapy.19968784724
phase variation in francisella tularensis affecting intracellular growth, lipopolysaccharide antigenicity and nitric oxide production.many microbial pathogens, such as mycobacterium spp. and salmonella spp., use macrophage intracellular growth or antigenic variation as mechanisms for avoiding the host immune system. in this work we present evidence to show that the intracellular pathogen francisella tularensis uses phase variation to alter antigenicity and the host macrophage nitric oxide response simultaneously, thereby modulating its intracellular growth. the lipopolysaccharide (lps) and lipid a of f. tularensis fails to sti ...19968793882
isolation of francisella tularensis from lymph node aspirate inoculated into a non-radiometric blood culture system. 19968801096
a shunt infection caused by francisella tularensis.we report the first case of a child with a shunt infection caused by francisella tularensis, the causative agent of tularemia. this patient is also unique in that the disease was limited to the central nervous system.19968817615
characterization of two unusual clinically significant francisella strains.we have isolated two phenotypically distinct nonfastidious francisella strains (fx1 and fx2) from the blood of compromised patients with pneumonia and compared them with eight other francisella strains, including francisella tularensis biovar tularensis, f. tularensis biovar novicida, and f. philomiragia. our isolates grew well on sheep blood agar, chocolate agar, modified thayer-martin agar, and trypticase soy agar. fx1 and fx2 were determined to be within the francisella genus by cellular fatt ...19968818897
[the resistance of francisella tularensis to the bactericidal action of normal serum as a criterion for evaluating the virulence of the bacterium].the study of the sensitivity of f. tularensis to the bactericidal action of normal serum (ns) revealed that all virulent cultures were resistant, while avirulent cultures were highly sensitive to ns. the synthesis of r-lipopolysaccharide (lps) by capsule-deficient (cap-) clones or the synthesis of s-lps by capsule-defective (cap+/-) clones of the avirulent phenotype of these bacteria had no influence on the sensitivity of these forms to ns, but ensured longer survival of cap+/- variants in the s ...19968820667
parasites and selected diseases of collared peccaries (tayassu tajacu) in the trans-pecos region of texas.fifty-five collared peccaries (tayassu tajacu) were collected from october 1988 through april 1991 from five counties within the trans-pecos region of texas (usa) to monitor for diseases and parasites. no endoparasites were recovered on gross examination. antibody to borrelia burgdorferi was documented in one (2%) of 55 specimens. three (6%) of 54 collared peccaries were positive for yersinia pestis antibodies. all collared peccaries were negative for antibodies against brucella spp., francisell ...19968827690
index of suspicion. case 1. diagnosis: erythema infectiosum (ei). 19968857202
francisella tularensis: host-parasite interaction. 19968861025
field investigations of tularemia in norway.in norway, tularemia is a common disease in small rodent and hare populations, where large outbreaks can be observed. in humans, the yearly number of cases is low, usually less than ten, with peaks up to 44 recorded in recent years. serological investigations on hunters and healthy school children nevertheless indicate, with up to 4.7% positivity in the latter group, that francisella tularensis low-grade infection is widespread. f. tularensis in co-culture with amoebae, e.g. achantamoeba castell ...19968861027
immunogenicity of a new lot of francisella tularensis live vaccine strain in human volunteers.a new lot of francisella tularensis live vaccine strain (lvs) was tested for immunogenicity in 19 human volunteers. scarification vaccination induced specific cell-mediated and humoral immune responses. we noted a significant rise in antibodies against irradiation-killed lvs, formalin-killed virulent strain schu4, and an ether extracted antigen preparation (eex) beginning 14 days after vaccination. a main target of the humoral immune response was lipopolysaccharide. eighty percent of vaccinated ...19968861030
live tularemia vaccine confers protection against lethal legionella and listeria infections in experimental animals.the efficacy of a live francisella tularensis vaccine strain to cause nonspecific immunity toward experimental legionellosis and listeriosis was studied. immunisation with tularemia vaccine protected over 80% and 17% of experimental animals against subsequent lethal challenge with legionella pneumophila and listeria monocytogenes, respectively. the protection was maximal during the first month following immunisation and declined thereafter. in order to delineate the immunostimulatory moieties of ...19968861031
the new vaccine strains (or variants) of francisella tularensis.a colony (n83) of the vaccine strain of francisella tularensis (15/10) and a strain (n268) isolated from a water sample in nature were revealed for susceptibility to cultivation at 42 degrees c. both strains had low virulence for white mice and were avirulent for guinea pigs but possessed high immunogenicity in these animals. the spontaneous mutant of vaccine strain 15/10 showed resistance to doxicycline and rifampicine (15/10 dox (r)40 rif (r)40). the obtained mutant had biological characterist ...19968861032
orchestration of the protective immune response to intracellular bacteria: francisella tularensis as a model organism.francisella tularensis is used as a model organism in studies of mechanisms behind the induction of a protective t-cell response in the mammalian host. protective immunity is associated with a cd4 and cd8 t-cell response towards a mosaic of proteins of f. tularensis and due to hla restriction, each individual selects her own mosaic. no single protein has so far been shown to be immunodominant. only live f. tularensis affords effective host protection. subcellular antigen preparations induce only ...19968861033
outer membranes of a lipopolysaccharide-protein complex (lps-17 kda protein) as chemical tularemia vaccines.immunisation with outer membranes of francisella tularensis induced an efficient protection in guinea pigs against challenge with the virulent strains 503 or 144/713 (type b biovar holarctica), both clinical isolates, and prevented the development of typical signs of infection in hamadryads (baboons), challenged with the virulent strain schu (type a, biovar tularensis) of f. tularensis. immunisation with a lipopolysaccharide protein complex isolated from the outer membranes afforded protection i ...19968861034
the immune response against francisella tularensis live vaccine strain in lps(n) and lps(d) mice.the impact of lps gene on the course of immune response against subcutaneous infection of mice with francisella tularensis live vaccine strain was studied. production and specificity of antibodies, cytotoxic responses of macrophages and nk-cells, spontaneous production ex vivo of cytokines il-1 alpha, il-2, il-4, il-6, il-10, ifn-gamma, and tnf-alpha in spleen cell cultures in c3h/hej (lps(d)) mice in comparison with c3h/hen (lps(n)) mice were tested. the value of ld(50) was significantly differ ...19968861035
cytokine expression in the liver of mice infected with a highly virulent strain of francisella tularensis.cytokine mrna expression was determined in the liver of mice subcutaneously inoculated with a lethal dose of the highly virulent strain fsc 041 of francisella tularensis subvar, tularensis or a sublethal dose of the live vaccine strain of f. tularensis subvar. palaearctica. expression of mrna for tnf-alpha, il-12, ifn-gamma, and il-10 was demonstrated within 48 h of inoculation, the kinetics being similar irrespective of bacterial strain used. thus, the expression of a cytokine response believed ...19968861036
role of two outer membrane antigens in the induction of protective immunity against francisella tularensis strains of different virulence.a crude outer membrane preparation from francisella tularensis live vaccine strain was used to immunise mice. immunised mice were completely protected from a f. tularensis challenge. we evaluated the role of two major outer membrane antigens in the induction of protective immunity, namely lipopolysaccharide and an outer membrane protein fopa. we presented fopa to the immune system using an aromatic amino acid dependent salmonella typhimurium as a vector. although mice mounted an immune response ...19968861037
francisella tularensis resistance to bactericidal action of normal human serum.lipopolysaccharide and outer membranes from the three virulent encapsulated (cap(+)) strains of three subspecies of francisella tularensis and their isogenic avirulent capsule-deficient (cap(-)) mutants were isolated. it was shown that the cap cells and their outer membranes almost completely consumed the available complement of normal human serum whereas cap(-) lps (r-lps), cap(+) cells and their components activated the complement less effectively. absorption of normal human serum with cap(-) ...19968861038
cryptic plasmid pfnl10 from francisella novicida-like f6168: the base of plasmid vectors for francisella tularensis.the plasmid pfnl1oo was created by ligation of escherichia coli plasmid pbr328 and plasmid pfnl1o from francisella novicida-like strain f6168. this plasmid was able to replicate and to express the genes for chloramphenicol and tetracycline resistance in both e. coli and f. tularensis. the origin of replication of pfnl1o, needed for the replication of pfnl1oo in f. tularensis, was mapped. a sau3a-deletion derivative of pfnl1oo, designated pfnl2oo, was constructed. this plasmid could replicate onl ...19968861039
construction of a shuttle vector for use in francisella tularensis.the characterisation of virulence factors of francisella tularensis has been hampered by the lack of genetic system for the bacterium. in this study, a shuttle vector was constructed that can replicate autonomously in f. tularensis and escherichia coli. to obtain this vector, the p15a replication origin of f. coli plasmid pacyc184 was introduced into a plasmid derivative of plasmid pfnl2oo, a plasmid which only can replicate in f. tularensis. the resulting shuttle vector, designated pkk2o2, harb ...19968861040
frequent isolation of francisella tularensis from dermacentor reticulatus ticks in an enzootic focus of tularaemia.a total of 924 questing dermacentor reticulatus (fabricius), 504 ixodes ricinus (l.), sixty haemaphysalis concinna koch and 718 mosquitoes (aedes spp.) were examined in a floodplain forest ecosystem during the 1994-95 outbreak of tularaemia in south moravia, czech republic. francisella tularensis was not isolated from h.concinna ticks or aedes spp. mosquitoes, whereas twenty-one isolates were recovered from the other haematophagous arthropods. dermacentor reticulatus revealed a significantly hig ...19968887334
amplification and restriction endonuclease digestion of a large fragment of genes coding for rrna as a rapid method for discrimination of closely related pathogenic bacteria.by use of primers specific to conserved regions of the rrna gene cluster, a discrete amplicon of approximately 5 kb was amplified by pcr from all 21 bacterial genera investigated. subsequent endonuclease digestion of the pcr product with haeiii distinguished between the three species of the human pathogen francisella spp. on the one hand and four clinically relevant genomic groups of acinetobacter spp. on the other hand. the described technique has the potential as a rapid method for discriminat ...19968940418
loss of either cd4+ or cd8+ t cells does not affect the magnitude of protective immunity to an intracellular pathogen, francisella tularensis strain lvs.normal mice readily survive a sublethal intradermal (i.d.) infection with francisella tularensis live vaccine strain (lvs), a model intracellular bacterium, and are strongly protected against subsequent lethal challenge. however, athymic nu/nu mice, which lack mature alphabeta tcr+ t lymphocytes, succumb to i.d. infection within 30 days. here we characterize the alphabeta t cell subpopulations necessary for both resolution of i.d. infection and generation of optimal protective immunity to lvs. b ...19968943413
detection of francisella tularensis by the polymerase chain reaction.francisella tularensis is the causative agent of tularaemia. effective antibiotic treatment of tularaemia is now available, but the early diagnosis of tularaemia remains a problem. four primers (three pairs) were designed to detect f. tularensis by the polymerase chain reaction (pcr), based on the previously published nucleotide sequence of t-cell epitopes of a f. tularensis membrane protein. amplification of purified f. tularensis chromosomal dna with the three pairs of primers resulted in thre ...19968958253
[the characterization of francisella tularensis mutants and subspecies by using monoclonal antibodies].monoclonal antibodies to f.tularensis cells, subspecies holarctica, were studied for the capacity of reacting with f.tularensis, subspecies nearctica, and its mutants having lower virulence and altered capacity for inducing protective immunity to tularemia in laboratory animals. among the antibody-producing hybridoma clones under study, clones f8/67 and c7/65 capable of distinguishing the mutants of f.tularensis, subspecies nearctica, with lower virulence than that of the initial strain were sel ...19969027167
francisella tularensis isolation from various clinical specimens. 199611866851
medical microbiologyrickettsiae are small, gram-negative bacilli that have evolved in such close association with arthropod hosts that they are adapted to survive within the host cells. they represent a rather diverse collection of bacteria, and therefore listing characteristics that apply to the entire group is difficult. the common threads that hold the rickettsiae into a group are their epidemiology, their obligate intracellular life ...199621413251
medical microbiologythe genus pasteurella was originally proposed and described by trevisan in 1887. it consisted of a group of nonmotile, small (0. 7 μm by 0. 5 μm), gram-negative coccobacilli often exhibiting a characteristic type of bipolar staining (fig. 29-1). most members of this genus are associated with severe, life-threatening systemic diseases involving both hemorrhagic pneumonia and septicemia. the first pathogen to be ...199621413268
correlation of the polysaccharide antigens of francisella tularensis with virulence in experimental mice.francisella tularensis gives rise to two distinct colony types, acriflavine agglutination test-positive (acf+) and -negative (acf-) colonies. the acf+ variants were exclusively low virulent in mice, while the acf- variants were shown to be either high or low virulent. three fractions, phosphate-buffered saline-extractable without heating, with heating at 60 c, and with heating at 100 c, were obtained from cultures of both the acf+ and acf- variants on agar media, and the polysaccharide antigens ...19958789061
[the characteristics of new species of pathogenic microorganisms in the genus francisella].the comparative study of newly discovered pathogenic bacteria of the genus francisella was carried out with the use of a complex of microbiological and serological methods. while having great similarity to the causative agent of tularemia, f. novicida, f. novicida-like bacteria and f. philomiragia had lesser growth requirements, some specific morphological and structural features, were capable of fermenting sucrose and exhibited low pathogenicity to experimental animals. the strains under study ...19958525727
[primers for the genus-specific detection of francisella tularensis in the polymerase chain reaction].primers for the detection of f.tularensis in the polymerase chain reaction (pcr) have been obtained. the method of pcr permits the identification of up to 10 f.tularensis cells in the analysis of pure and mixed cultures, as well as suspensions prepared from the organs of laboratory animals. the possibility of the simultaneous analysis of several samples makes this system for the detection of f.tularensis useful for epidemiological investigations.19958525740
chemiluminescent immunoassay (clia) for the detection of brucellosis and tularaemia antigens.the detection of brucellosis and tularaemia infection agents is of particular interest for medical practice. the possibility of using enhanced chemiluminescence reactions for the determination of these agents is studied in this work. light intensity depends on both the conjugate concentration used and the conditions at which the adsorption was performed. optimal conditions for these test-systems were: approximately 20 micrograms/ml of ig and 200 micrograms/ml (titre 1:20) of conjugate. as is see ...19958533600
prevalence of ticks infected with francisella tularensis in natural foci of tularemia in western slovakia.the prevalence of ticks infected with f. tularensis was followed during a systematic surveillance in endemic area of tularemia in western slovakia over the years 1984-93. ticks were collected from vegetation in localities of podunajské biskupice, in the vicinity of the capital of slovakia, bratislava, near the river danube. in total 6033 ticks, mostly adults of dermacentor reticulatus and ixodes ricinus (4994 and 1004, respectively) and 35 nymphs of haemaphysalis concinna, were examined for the ...19958549717
[the determination of the duration of postvaccinal immunity against tularemia]. 19958553755
role of lipopolysaccharide and a major outer membrane protein from francisella tularensis in the induction of immunity against tularemia.a crude outer membrane preparation from francisella tularensis live vaccine strain (lvs) was used to immunize mice. immunized mice were completely protected from a f. tularensis challenge. we evaluated the role of two major outer membrane antigens in the induction of protective immunity, namely lipopolysaccharide and an outer membrane protein fopa. we presented fopa to the immune system using an aromatic amino acid-dependent salmonella typhimurium as a vector. although mice mounted an immune res ...19958578807
electroporation of francisella tularensis. 19957550729
[methodical bases of the use of erythrocytic diagnostic agents as phagocytosis objects].the error in assessment of the neutrophil phagocytic activity is 5.8%. this is attained by removal of conglomerations of phagocytosis objects and by ruling out the minimal variations in the duration of contact between the blood and foreign corpuscles and preparation of smears to be examined on the same slide. the content of up to 90% red cells does not influence the neutrophil phagocytic activity, and higher concentration reduces its level.19957582767
levels of interleukin 6 and tumor necrosis factor in serum from humans vaccinated with live, attenuated francisella tularensis.the levels of interleukin 6 (il-6) and tumor necrosis factor alpha in serum did not change significantly during the course of immunization with the live vaccine strain of francisella tularensis. higher levels of circulating il-6 were found in the sera of vaccinees with good antibody responses than in the sera from nonresponders. preimmunization levels of il-6 in serum were also higher in responders than in nonresponders.19957583930
seroepidemiologic study of three zoonoses (leptospirosis, q fever, and tularemia) among trappers in québec, canada.this study was undertaken to evaluate the prevalence of antibodies against francisella tularensis, coxiella burnetii, and certain serovars of leptospira interrogans among trappers in québec, canada. muskrat trapping was identified as a risk factor for f. tularensis infection, whereas having a cat at home apparently protected trappers against infection by l. interrogans. high percentages of control sera were positive for antibodies against c. burnetii (15%) and l. interrogans (5%), most frequentl ...19957583933
analysis of the dnak molecular chaperone system of francisella tularensis.we have cloned the francisella tularensis (ft) grpe-dnak-dnaj heat-shock genes which are organized in that order. these genes allow heterologous genetic complementation of each respective mutant strain of escherichia coli (ec) for bacteriophage lambda growth. the nucleotide sequences of the ft grpe-dnak-dnaj genes and the deduced amino-acid sequences share significant homologies with their respective ec counterparts. the ft dnak and dnaj proteins cross-react with polyclonal antibodies raised aga ...19957590305
adjuvanticity of iscoms incorporating a t cell-reactive lipoprotein of the facultative intracellular pathogen francisella tularensis.immunostimulating complexes (iscoms) are known to be highly effective adjuvants for envelope antigens of viral agents, but have not been evaluated for use with antigens of intracellular bacteria. balb/c mice were subcutaneously immunized with iscoms into which the t cell-reactive membrane protein tul4 of francisella tularensis had been incorporated. spleen cells from the immunized mice responded in vitro to tul4 and to heat-killed f. tularensis live vaccine strain (lvs) with proliferation and pr ...19957631511
[the effect of recombinant tumor necrosis factor on antibody formation in mice immunized with a preparation of the outer membranes from francisella tularensis].the influence of exogenic human recombinant tumor necrosis factor (tnf-alpha) on antibody production in mice immunized with the preparation of f.tularensis outer membranes (om) was studied. tnf-alpha was injected into mice in doses of 0.001-10 i.u. before and simultaneously with the injection of the preparation of f.tularensis om. the levels of tularemia antibodies, determined by elisa techniques, and the number of antibody-producing cells (apc) were studied. the study revealed that recombinant ...19957653140
[the activity of the phagocytic bactericidal systems in intact guinea pigs and in guinea pigs immunized against tularemia].the activities of nadp-oxidase and glucose-6-phosphate dehydrogenase in mononuclear phagocytes and polymorphonuclear leukocytes (pml) during the phagocytosis of francisella tularensis and the influence of immunization of on the activity of oxygen-dependent metabolism were studied. the phagocytosis of f.tularensis was found to be accompanied by a rise in the activity of nadp.h-oxidase and glucose-6-phosphate dehydrogenase. in the process of immunogenesis the rearrangement of the enzymatic system ...19957653143
mixed natural focus of tick-borne encephalitis, tularemia and haemorrhagic fever with renal syndrome in west slovakia.total of 923 small mammals of 7 species were collected in locality záhorská ves, west slovakia, in 1990-1992. among examined small mammal species it was clethrionomys glareolus (48.7% of total, 17.5% positive for tick-borne encephalitis (tbe) virus antibodies), apodemus flavicollis (29.7% of total, 17.5% positive), a. sylvaticus (11.3% of total, 16.3% positive), and microtus arvalis (6.2% of total, 10.5% positive). the most abundant tick species (larval and nymphal stages) on small mammals was i ...19957676942
cell-mediated and humoral immune responses after vaccination of human volunteers with the live vaccine strain of francisella tularensis.the specific humoral and cell-mediated immune responses of human volunteers vaccinated with the francisella tularensis live vaccine strain (lvs) were evaluated. in the search for an optimal antigen to measure the immunogenicity of the vaccine in an enzyme-linked immunosorbent assay, we tested irradiation-killed lvs, an aqueous ether extract of the lvs (eex), lipopolysaccharide (lps) from lvs, and a virulent strain (schu4). volunteers were immunized with lvs by scarification. immunoglobulin g (ig ...19957697521
live tularemia vaccine but not proteins purified from francisella tularensis can confer protection against lethal listeria infection in mice.immunization of balb/c mice with francisella tularensis vaccine strain 15/10 conferred significant protection against subsequent listerial infection. since immunostimulatory activities could apparently be relevant to surface components of the bacterium, a technique for purification of cell wall proteins was developed. the scheme designed consisted of triton x-100 extraction with subsequent fplc chromatography steps, and resulted in the isolation of homogeneous proteins with molecular masses of 5 ...19957748535
heat stress alters the virulence of a rifampin-resistant mutant of francisella tularensis lvs.we have studied the stress response of a rifampin-resistant mutant of francisella tularensis lvs. this mutant, rif 7, was avirulent with an intraperitoneally administered 50% lethal dose greater than 10(7) cfu in a murine model of infection. exposure of rif 7 to heat stress for 5 h in vitro resulted in a 2-log decrease in its 50% lethal dose (p < 0.02). the increase in virulence was dependent on the time of exposure to high temperature and was maximal at 5 h. envelope preparations from heat-stre ...19957806352
cytokine expression in the liver during the early phase of murine tularemia.cytokine expression was determined in the livers of mice inoculated subcutaneously with francisella tularensis lvs. during the first 48 h of infection, there was a logarithmic increase of bacteria in the liver, with a doubling time of 2.5 h. within 48 h, tumor necrosis factor alpha (tnf-alpha), interleukin 10 (il-10), il-12, and gamma interferon (ifn-gamma) mrnas were expressed, and production of tnf-alpha and ifn-gamma was demonstrated. there was no expression within 96 h of mrna from il-2, il- ...19957822019
growth of francisella tularensis lvs in macrophages: the acidic intracellular compartment provides essential iron required for growth.murine macrophages supported exponential intracellular growth of francisella tularensis lvs in vitro with a doubling time of 4 to 6 h. lvs was internalized and remained in a vacuolar compartment throughout its growth cycle. the importance of endosome acidification to intracellular growth of this bacterium was assessed by treatment of lvs-infected macrophages with several different lysosomotropic agents (chloroquine, nh4cl, and ouabain). regardless of the agent used or its mechanism of action, ma ...19957890413
[the modification of the clastogenic action of 131i in the bone marrow cells of rats immunized with a tularemia vaccine].the influence of immunization of wistar rats with the tularemia vaccine (tv) on the clastogenic effect of 131i was studied. the preliminary immunization of rats with tv significantly reduces the number of aberrant metaphases in bone marrow cells by 36.4% one day and by 61.6% eight days after the administering of the radionuclide in comparison with non-immunized animals. possible mechanisms of anticlasterogenesis in animals immunized with tv are discussed.19947900198
increased synthesis of dnak, groel, and groes homologs by francisella tularensis lvs in response to heat and hydrogen peroxide.the response of the facultative intracellular bacterium francisella tularensis lvs to stress was assayed by pulse-labeling with [35s]methionine followed by two-dimensional gel electrophoresis and autoradiography. a temperature increase from 37 to 42 degrees c or exposure to 5 mm hydrogen peroxide induced increased syntheses of at least 15 proteins. among these proteins were a 75-, a 60-, and a 10-kda protein. by n-terminal sequence analysis, these three proteins were found to be extensively homo ...19947903283
reduced virulence of rifampicin-resistant mutants of francisella tularensis.rifampicin-resistant mutants of a live vaccine strain (lvs) of francisella tularensis were produced and screened for virulence in mice; 4 avirulent clones with intraperitoneal (ip) ld50s > 10(6) cfu, compared with 10(2) cfu for lvs, were characterized. growth characteristics at 37 degrees c, surface envelope proteins, and lipopolysaccharide profiles of resistant mutants were identical to those of lvs. polymerase activity of the mutants was more resistant than the enzyme from lvs to the inhibitor ...19947930725
survey for selected diseases in nutria (myocastor coypus) from louisiana.thirty-two trapper-caught nutria (myocastor coypus) from east baton rouge, iberville, tangipahoa, and st. helena parishes in louisiana (usa) were sampled for several disease agents. antibodies against toxoplasma gondii, chlamydia psittaci, francisella tularensis, leptospira spp., and encephalomyocarditis virus were detected in 7%, 14%, 0%, 7%, and 0% of nutria, respectively. both animals seropositive for leptospirae were positive for l. interrogans serovar canicola. no salmonella spp. were isola ...19947933295
[the effect of the antigenic fractions of the outer membrane of francisella tularensis on the t-cell immunity indices].the immunological evaluation of the influence of individual gel-chromatographic antigenic fractions (gaf) of f. tularensis outer membrane on different forms of t-cell reactiveness, such as delayed hypersensitivity (dh), proliferation of lymphocytes in the reaction of blast transformation (rbt) and mixed lymphocyte culture (mlc), has been made. as revealed in this study, gaf isolated from f. tularensis produce a pronounced immunomodulating effect on the processes linked with polyclonal activation ...19947941852
[the search for and isolation of an antiphagocytic factor in francisella tularensis].in this study a search for f. tularensis antiphagocytic factor and an attempt for its isolation were made. for this purpose a fraction of f.tularensis water-saline extract saturated 55-60% with ammonium sulfate was split into separate components by preparative methods. one of them, consisting of two antigens of glycoprotein nature, had the capacity of decreasing the digestion of f.tularensis by guinea pig peritoneal macrophages about 10 times. the study revealed that the protein of the preparati ...19947941862
[the immunological efficacy of francisella tularensis outer membranes for hamadryas baboons].the protective properties of the preparation of f. tularensis outer membranes (om), obtained from f. tularensis vaccine strain 15, were studied in experiments on hamadryas baboons challenged subcutaneously with f. tularensis virulent strain schu (nonarctic subspecies). the subcutaneous immunization with the om preparation prevented the development of clinically pronounced infection in more than 70% of the monkeys challenged with f. tularensis strain schu in a dose of 787 live microbial cells 30 ...19947941871
streptomycin and alternative agents for the treatment of tularemia: review of the literature.because of the recent lack of availability of streptomycin--currently considered the drug of choice for the treatment of tularemia--we reviewed the literature on alternative drugs that have been used for this purpose. in addition, we reviewed data on the in vitro susceptibility of francisella tularensis to a wide variety of agents. the rate of cure for streptomycin was 97%, with no relapses. for gentamicin and tetracycline, respectively, the rates of cure were 86% and 88%, the rates of relapse w ...19947948556
tularemia. 19947956338
cd4+ and cd8+ t-cell-dependent and -independent host defense mechanisms can operate to control and resolve primary and secondary francisella tularensis lvs infection in mice.immunity to experimental infection with the facultative intracellular bacterium francisella tularensis is generally considered an example of t-cell-mediated, macrophage-expressed immunity. however, the results of the present study indicate that t-cell-independent mechanisms are also important in anti-francisella defense. they show that mice selectively depleted of cd4+, cd8+, or both t-cell populations by treatment with t-cell subset-specific monoclonal antibodies remained capable of controlling ...19947960142
increased encapsulation and virulence of francisella tularensis live vaccine strain (lvs) by subculturing on synthetic medium.francisella tularensis live vaccine strain (lvs), taken directly from lyophilized vials, did not appear to have a capsule and had low virulence for balb/c mice. when this strain was subcultured on chamberlain's synthetic medium (ph 6.5), it became extensively capsulated (1-5 micron in diameter) and its virulence for balb/c mice increased about 1000-fold. we conclude that the virulence of the attenuated vaccine strain, f. tularensis lvs, may still be influenced by growth conditions.19947975855
[europium-labelled staphylococcus aureus protein a as a reagent for determining specific antibodies].in this work the conditions of labeling protein a with europium ions were studied and the conjugates obtained in this study were compared with traditional peroxidase conjugates currently used in immunochemistry. the conjugates of protein a with eu3+ chelate were obtained with the use of cyclic dianhydride of diethylenetriaminepentaacetic acid (dadetpa). conjugation methods with the use of dadetpa was shown to permit obtaining high-quality conjugates with europium chelates. europium-labeled prote ...19947992539
neutrophils are critical for host defense against primary infection with the facultative intracellular bacterium francisella tularensis in mice and participate in defense against reinfection.it is generally believed that immunity to experimental infection with the facultative intracellular bacterium francisella tularensis is an example of t-cell-mediated immunity that is expressed by activated macrophages and mediated by francisella-specific t cells. according to the results presented herein, neutrophils are also essential for defense against primary infection with this organism. it is shown that mice depleted of neutrophils by treatment with the granulocyte-specific monoclonal anti ...19948005668
persistence of cell-mediated immunity and decline of humoral immunity to the intracellular bacterium francisella tularensis 25 years after natural infection.the humoral and cell-mediated immune responses to the facultative intracellular pathogen francisella tularensis were studied in subjects who had tularemia 25 years earlier. serum agglutinin titers were low. of 53 subjects, only 2 had a titer > 40. the f. tularensis-induced t cell response, on the other hand, was vigorous and in fact similar in magnitude to the response to purified protein derivative (ppd) of mycobacterium tuberculosis. t cells from 44 of 52 subjects showed a significant (p < .05 ...19948014484
nitric oxide-independent killing of francisella tularensis by ifn-gamma-stimulated murine alveolar macrophages.alveolar macrophages (ams) were analyzed for ability to support replication of the intracellular bacterium francisella tularensis live vaccine strain (lvs). am supported in vitro growth (2 to 3 logs over 5 days) of lvs with a doubling time of 8 +/- 0.8 h. ams were analyzed for responsiveness to rifn-gamma for destruction of this lung pathogen. am treated with 50 u/ml rifn-gamma allowed early growth of bacteria (six doublings over 48 h) but between 48 and 96 h rifn-gamma-treated am eliminated 1.5 ...19948027551
transfer of immunity against lethal murine francisella infection by specific antibody depends on host gamma interferon and t cells.both serum and spleen cells from mice immune to francisella tularensis transfer protection to naive recipients. here we characterize the mechanism of protection induced by transfer of immune mouse serum (ims). ims obtained 4 weeks after intradermal infection with 10(3) bacteria of the live vaccine strain (lvs) contained high levels of immunoglobulin g2 (igg2a) and igm (end point titers, 1:16,600 and 1:7,200, respectively) and little igg1, igg2b, or igg3. lvs-specific antibodies were detected 5 d ...19948039881
passive protection of mice against lethal francisella tularensis (live tularemia vaccine strain) infection by the sera of human recipients of the live tularemia vaccine.the relative role that humoral immunity plays in protection against infection with the intracellular bacterium, francisella tularensis, remains controversial. cellular immunity is thought to play the major and perhaps only role. the authors, in this article, investigate the immunologic and protective properties of immune serum collected from human recipients of the live tularemia vaccine (lvs). sera of recipients of the vaccine demonstrated reactivity with the vaccine strain by enzyme-linked imm ...19948042659
analysis of 16s ribosomal dna sequences of francisella strains and utilization for determination of the phylogeny of the genus and for identification of strains by pcr.the 16s ribosomal dnas (rdnas) of two strains of francisella tularensis and one strain of francisella philomiragia were sequenced. on the basis of phylogenetic analysis data, the genus francisella was placed in the gamma subclass of the proteobacteria. the most closely related organism was the intracellular bacterium wolbachia persica. the sequenced 16s rdna molecules of the francisella species exhibited very high levels of similarity (98.5 to 99.9%). two variable regions, comprising 390 to 450 ...19948123561
early recognition of atypical francisella tularensis strains lacking a cysteine requirement.seven cultures referred to in our laboratories as unidentified gram-negative bacilli or haemophilus species were identified as atypical strains of francisella tularensis lacking a requirement for cysteine or enriched medium for growth. the use of cellular fatty acid composition analysis facilitated early recognition of this pathogen and prompt implementation of appropriate biosafety measures.19948150973
[the protective properties of the outer membranes of francisella tularensis in an experimental infection in guinea pigs].subcutaneous immunization, made in a single injection, with outer membrane preparations obtained from f.tularensis vaccine strain 15 and virulent strain a'cole results in intensive immunity to tularemia in guinea pigs, ensuring the protection of 60-100% of the animals within a month after challenge with f.tularensis virulent strain 503 in a dose of 1,000 dcl. the development of protective effect induced by f.tularensis outer membranes can be observed during the first 24 hours and reaches its max ...19948184621
life and death of an intracellular pathogen: francisella tularensis and the macrophage. 19948251580
[transstadial transmission of francisella tularensis by ixodes ricinus ticks infected during the nymphal stage].the degree of infection of nymphs of ixodes ricinus which finished their feeding on experimentally infected mice on the day of their death from tularaemia represented more than 10(7) cells of francisella tularensis per tick after feeding. the high degree of positivity was preserved in ticks also during one month of metamorphosis. transstadial transmission of the agent from the stage of nymph to the stage of imago was confirmed in adults either by cultivation or by experiments attempting to trans ...19947850217
[an immunological analysis of bacterial persistence in the bone marrow].a method for the evaluation of bacterial persistence in the bone marrow in association with particular clonogenic target cells was developed. the method was based on the negative selection of cells expressing microbial antigens after treatment with hyperimmune antiserum specific to a given infective agent and the subsequent quantitation of target cells thus eliminated in appropriate assays. using this approach, we demonstrated that mycoplasma arthritidis and l-forms of streptococcus strain l-406 ...19947856346
serum-sensitive mutation of francisella novicida: association with an abc transporter gene.francisella novicida is a facultative intracellular pathogen that can survive and grow in macrophages by preventing phagolysosomal fusion. in this study in vitro cassette mutagenesis was used to generate a library of insertion mutants of f.novicida. two related mutants, km14 and km14s, initially identified as defective for growth in macrophages, were found to be sensitive to serum. these mutants were also found to grow approximately 1000-fold less well in the livers and spleens of infected mice. ...19947881549
isolation of a francisella tularensis mutant that is sensitive to serum and oxidative killing and is avirulent in mice: correlation with the loss of mind homologue expression.we constructed mutant strains of francisella tularensis biotype novicida by insertional mutagenesis with a kanamycin resistance (kmr) cassette. one mutant, kem7, was defective for survival in macrophages in comparison with the wild-type (wt) strain and a random insertion strain, kem21. while all three strains exhibited intracellular growth, the number of viable kem7 present after 24-48 h of infection was approximately 10 times less than that of wt or kem21. this observation was apparently due to ...19947813885
the tularaemia vaccine.tularaemia is a disease caused by the facultative intracellular bacterium francisella tularensis. vaccination resulting in protective immunity is induced by live vaccine only. such vaccination can be performed by scarification utilizing the live vaccine strain of f. tularensis (f. tularensis lvs), which results in good but not complete protection. humoral as well as cell-mediated immunity are induced by vaccination and it has been shown that cell-mediated immunity is a prerequisite for protectio ...19947764815
comparative analysis of antibodies to francisella tularensis antigens during the acute phase of tularemia and eight years later.approximately 8 years after treatment for tularemia, 14 of 22 (63.6%) individuals tested still had a positive microagglutination test for francisella tularensis antibodies. an enzyme-linked immunosorbent assay for anti-f. tularensis outer membrane antibodies was positive for 55% (immunoglobulin a [iga]), 95% (igg), and 27% (igm) of the late-phase sera, but with antibody levels significantly reduced from those in the acute-phase sera. igg and iga antibody levels in the late-phase sera showed sign ...19947496953
lipoarabinomannan from mycobacterium tuberculosis modulates the generation of reactive nitrogen intermediates by gamma interferon-activated macrophages.lipoarabinomannan derived from the virulent erdman strain and a rapidly growing, laboratory-attenuated strain of mycobacterium tuberculosis were evaluated for their ability to modulate the production of nitric oxide (no) by macrophages activated with ifn-gamma or ifn-gamma and lps. it was observed that in macrophages pretreated with 100 micrograms ml-1 lam, the no induced by ifn-gamma alone was augmented while the no induced ifn-gamma and lps was reduced. lam was also shown to synergize with ifn ...19948061654
[isolation and molecular-genetic characteristic of a cryptic plasmid from the francisella novicida like f6168 strain].a 4 kb plasmid dna has been isolated from francisella novicida like strain f6168. restriction map of the plasmid was constructed for restriction endonucleases hindiii, xbai, ecorv, bgiii. the plasmid pfn10 has been shown to be stably inherited by f. tularensis. the use of pfn10 for the construction of plasmid vectors for microorganisms of the genus francisella is discussed.19948065386
[study of nonpathogenic strains of francisella, brucella and yersinia as producers of recombinant beta-endorphin]. 19948068916
nitric oxide: cytokine-regulation of nitric oxide in host resistance to intracellular pathogens.to discover how nitric oxide (no) synthesis is controlled in different tissues as cells within these tissues combat intracellular pathogens, we examined three distinctively different experimental murine models designed for studying parasite-host interactions: macrophage killing of leishmania major; nonspecific protection against tularemia (francisella tularensis) by mycobacterium bovis (bcg); and specific vaccine-induced protection against hepatic malaria with plasmodium berghei. each model para ...19947537721
[the association of tetrahymena pyriformis infusoria with representatives of the genus francisella in an experiment]. 19938079568
tularemia: treatment failures with outpatient use of ceftriaxone.tularemia, an infection caused by the coccobacillus francisella tularensis, can be a difficult disease process to diagnose and treat. the difficulty in treating this disease is related to the pathophysiology of the infection and the toxicity of the antimicrobial agents presently recommended for treatment. recent in vitro data have suggested that antimicrobial drugs other than standard agents (streptomycin, gentamicin, chloramphenicol, or tetracycline) may be effective. we present eight cases of ...19938110955
[the characteristics of the biological properties of capsule-free variants of francisella tularensis].comparative study of the properties of initial capsular (cap+) and non-capsular (cap-) f. tularensis strains has revealed that the non-capsular variants have their specific biological features. the characteristic features of these variants are avirulence and inability to produce an immunogenic effect in sensitive laboratory animals. cap- mutants, depending on the method of their obtaining, may exhibit different sensitivity to some antibacterial preparations. in contrast to the initial virulent s ...19938067085
[the effect of antigenic fractions of the outer membrane in francisella tularensis on the functional activity of macrophages].the influence of different gel-chromatographic antigenic fractions (gaf) of the membrane of f. tularensis, strain a'cole, on different forms of reactivity of mouse peritoneal macrophages, such as the adhesion, ingestion and presentation of antigen on the cell surface, has been immunologically evaluated. gaf isolated from f. tularensis have been shown to produce a pronounced modulating effect on all forms of macrophagal functional activity under study. thus, gaf ii with a molecular weight of 85-2 ...19938067125
identification and classification of different isolates of francisella tularensis.the causative agent of tularemia, francisella tularensis, occurs in two main biovars, the highly virulent f. t. biovar tularensis, found in north america; and the less virulent biovar palaearctica, found all over the northern hemisphere. two other biovars have been proposed, f. t. biovar mediaasiatica and f. t. biovar palaearctica var. japonica. in sweden tularemia is most frequently observed in man and varying hares (lepus timidus), and occasionally in other species. tularemia in hares is norma ...19937510445
[a highly sensitive, homogeneous method for determining antibodies and antigens by using liposomes, monoclonal antibodies and complement].a simple and sensitive method for the determination of francisella tularensis antigen and antibodies to this antigen by means of the complement lysis of liposomes sensitized with f. tularensis lipopolysaccharide (lps) is proposed. the possibility of participation of monoclonal antibodies (mcab) in the complement-dependent lysis of liposomes has been studied. the method permits the detection of 50-100 ng/ml of soluble lps antigen in the presence of antiserum or mcab igg f-b11-x and of 50-10 ng/ml ...19937520654
[the determination of the antigenic determinant of protective monoclonal antibodies specific to the francisella tularensis lipopolysaccharide].f. tularensis lipopolysaccharide (lps) was studied with the use of monoclonal antibodies (mcab) having protective properties. the binding site of these mcab (igg2a) is localized on the o-chain of lps. in contrast to lps isolated from vaccine strain 15, lps isolated from f. tularensis cells in the r-form has no o-chains and does not interact with mcab.19937520655
production and partial characterization of hybridoma clones secreting monoclonal antibodies against francisella tularensis.hybridomas secreting monoclonal antibodies against francisella tularensis cellular antigens were produced and characterized. these monoclonal antibodies reacted with f. tularensis in elisa but not by immunoblot, indicating that the antibodies are directed against conformational epitopes. one of these monoclonal antibodies was directed against outer membrane protein (omp) components, and the remainder are likely directed against capsular components. the omp-specific monoclonal antibodies are f. t ...19937686137
a serologic survey for some bacterial and viral zoonoses in game animals in the czech republic.between 1986 and 1991, sera were collected from 33 roe deer (capreolus capreolus), 24 red deer (cervus elaphus), four fallow deer (dama dama), two mouflon (ovis musimon), 34 wild boars (sus scrofa), and 48 hares (lepus europaeus) shot in two areas of the czech republic. collectively, the sera contained antibodies to coxiella burnetii (prevalence of 12%), francisella tularensis (4%), brucella spp. (2%), central european tick-borne encephalitis virus (8%), tahyna (california serogroup) virus (36%) ...19938258864
[the additive synthesis of a regulatory peptide in vivo: the administration of a vaccinal francisella tularensis strain that produces beta-endorphin].it has been shown, that vaccine strain of tularemia microbe, f.t.ise., which produced recombinant beta-endorphin, when administered to cba mice. it was shown to increase in the threshold level of pain sensitivity and is associated with peptides associated changes the stereotypic behavior. the observed correlated in time with the pattern of the dynamics of culture in the experimental animals and were associated with the level of recombinant beta-endorphin synthesis.19938274686
the entry and intracellular multiplication of francisella tularensis in cultured cells: its correlation with virulence in experimental mice.five acriflavine agglutination test-positive (acf+) colonies and five negative (acf-) colonies were isolated from each of the four strains (ebina, cmb2, n9, and schu) of francisella tularensis, and the correlation between the virulence in experimental mice and the entry and intracellular multiplication in cultured mouse fibroblast cells (l-929 cells) was examined. all of the acf- colonies derived from the ebina and cmb2 strains were highly virulent in mice, readily entering and growing well in t ...19938295562
x-ray microanalysis of guinea pigs peripheral blood t and b lymphocytes: before and after antigen stimulation.t and b lymphocytes from with francisella tularensis (lvs) immunized guinea pigs were separated and stimulated in vitro with the specific antigen. their chemical composition was studied in comparison by x-ray microanalysis before and after stimulation. different elemental spectra of normal t, b and t-suppressor cells were obtained. the common elements were p, s, k, cl and as; i was present only in b cells; cr and na were detected only in t suppressor cells. after stimulation the spectra of these ...19938298431
[transstadial transmission of francisella tularensis in the tick, ixodes ricinus, infected during the larval stage].based on previous studies which proved the decisive importance of the degree of bacteraemia of experimentally infected white mice for the degree of infection of ticks ixodes ricinus the authors confirmed the possibility of transstadial transmission of francisella tularensis from larvae via nymphs to imagos by the detection of germs in the ticks and by experiments attempting their transmission to white mice. this applied to imagos even one year after the infection of larvae. transmission was reco ...19938348625
use of immunoelectron microscopy to demonstrate francisella tularensis.three immunoelectron microscopy (iem) methods were employed to show laboratory-cultivated francisella tularensis. by the iem assays, f. tularensis was distinguished from four antigenically distinct gram-negative bacteria. iem should be a valuable tool for confirming presumptive isolates of f. tularensis and may potentially be useful for demonstrating other medically important bacteria.19938349780
liposome-encapsulated ciprofloxacin is effective in the protection and treatment of balb/c mice against francisella tularensis. 19938354928
Refresh
firstprev
...11121314151617181920...
nextlast
Displaying items 1401 - 1500 of 2254