Proc Natl Acad Sci U S A, 2002 Dec 24, 99(26), 16619 - 24 Epub 2002 Dec 10. Direct inhibition by nitric oxide of the transcriptional ferric uptake regulation protein via nitrosylation of the iron; D'Autreaux B et al.; Ferric uptake regulation protein (Fur) is a bacterial global regulator that uses iron as a cofactor to bind to specific DNA sequences . The function of Fur is not limited to iron homeostasis . A wide variety of genes involved in various mechanisms such as oxidative and acid stresses are under Fur control . Flavohemoglobin (Hmp) is an NO-detoxifying enzyme induced by NO and nitrosothiol compounds . Fur recently was found to regulate hmp in Salmonella typhimurium, and in Escherichia coli, the iron-chelating agent 2,2'-dipyridyl induces hmp expression . We now establish direct inhibition of E . coli Fur activity by NO . By using chromosomal Fur-regulated lacZ reporter fusion in E . coli, Fur activity is switched off by NO at micromolar concentration . In vitro Fur DNA-binding activity, as measured by protection of restriction site in aerobactin promoter, is directly sensitive to NO . NO reacts with Fe(II) in purified FeFur protein to form a S = 12 low-spin FeFur-NO complex with a g = 2.03 EPR signal . Appearance of the same EPR signal in NO-treated cells links nitrosylation of the iron with Fur inhibition . The nitrosylated Fur protein is still a dimer and is stable in anaerobiosis but slowly decays in air . This inhibition probably arises from a conformational switch, leading to an inactive dimeric protein . These data establish a link between control of iron metabolism and the response to NO effects. Microbes Infect, 2002 Nov, 4(14), 1409 - 15 Co-localization of quantitative trait loci regulating resistance to Salmonella typhimurium infection and specific antibody production phenotypes; Trezena AG et al.; Salmonella enterica serotype typhimurium is a facultative intracellular bacteria that induces systemic infection in mice . Resistance to this pathogen is under polygenic control in which Nramp1 is the major gene involved . Lines of mice obtained by selective breeding for high (HIII) or low (LIII) antibody response to flagellar antigens of salmonellae showed significant susceptibility differences, although both the lines display Nramp1(R) alleles . The HIII line was extremely susceptible to infection, while the LIII line was resistant . In order to examine the cellular and genetic mechanisms involved in this distinct pattern of resistance, HIII and LIII mice were analyzed for IFNgamma and IL4 production and screened for quantitative trait loci involved in S . typhimurium infection, using several polymorphic microsatellites . In the present work, HIII mice showed an IFNgamma downregulation in the early phase of infection when compared with LIII animals . No interline differences in IL4 production were verified . The loci screening was performed on immunized F2 intercrosses obtained from HIII and LIII mice . Three antibody-controlling chromosomal regions were coincident, and another was mapped near one of the four loci known to affect susceptibility to S . typhimurium . These results indicate a major role of IFNgamma in our model, and suggest the co-localization of quantitative trait loci modulating both infection and antibody production phenotypes. Microbes Infect, 2002 Nov, 4(14), 1379 - 87 Polymorphonuclear leukocyte migration across model intestinal epithelia enhances Salmonella typhimurium killing via the epithelial derived cytokine, IL-6; Nadeau WJ et al.; The host response to Salmonella typhimurium involves movement of polymorphonuclear leukocytes (PMN) across the epithelium and into the intestinal lumen . Following their arrival in the lumen, the PMN attempt to combat bacterial infection by activating antimicrobial defenses such as granule release, oxidative burst, phagocytosis, and cell signaling . We sought to examine PMN-S . typhimurium interaction following PMN arrival in the lumenal compartment . Here, for the first time, we demonstrate that PMN that have transmigrated across model intestinal epithelia have an enhanced ability to kill S . typhimurium . Our data provide evidence to indicate that the extracellular release of the primary and secondary granules of PMN, myeloperoxidase and lactoferrin, respectively, is correlated with enhanced bacterial killing . Furthermore, epithelial cells, during PMN transmigration, release the cytokine IL-6 . IL-6 is known to increase intracellular stores of Ca(2+), and we have determined that this epithelial released cytokine is not only responsible for priming the PMN to release their granules, but also stimulating the PMN to kill S . typhimurium . These results substantiate the pathway in which PMN transmigration activates the epithelial release of IL-6, which in turn increases intracellular Ca(2+) storage . Our results, herein, extend this pathway to include an enhanced PMN granule release and an enhanced killing of S . typhimurium. Pharmacogenetics, 2002 Dec, 12(9), 677 - 89 Differential activation of promutagens by alloenzymes of human sulfotransferase 1A2 expressed in Salmonella typhimurium; Meinl W et al.; Various enzymatically formed sulfuric acid esters are chemically reactive and mutagenic . This metabolic activation pathway is not detected in standard in-vitro mutagenicity test systems . We describe the construction of Salmonella typhimurium TA1538-derived strains expressing alloenzymes *1, *2, *3, *5, *6 of human sulfotransferase 1A2 (SULT1A2) . The reference compounds, 1-hydroxymethylpyrene (1-HMP), N-hydroxy-2-acetylaminofluorene (OH-AAF) and 2-hydroxylamino-5-phenylpyridine (OH-APP), were activated to mutagens in these strains . Their activity differed 7- to 16-fold between strains expressing various alloenzymes . It was strongest and weakest in the strains expressing the common alloenzymes, *1 and *2, respectively . The SULT1A2 protein expression levels, and the V(max) and K(m) values with the reference substrate 4-nitrophenol, varied 2.5-, 4-, and 110-fold, respectively, in cytosolic preparations from strains TA1538-SULT1A2*1 and *2 . Strains with varying protein levels were constructed via insertion of silent mutations in the 5'-part of the cDNA . TA1538-SULT1A2*1Z and TA1538-SULT1A2*2Y showed equal expression levels of alloenzymes *1 and *2, respectively, which were 3 times above those of TA1538-SULT1A2*1 . The mutagenicity of OH-AAF and OH-APP was unchanged in strain TA1538-SULT1A2*1Z versus *1, and moderately increased in TA1538-SULT1A2*2Y versus *2 . The influence of the protein level was stronger with 1-HMP . Nevertheless, mutagenic activity of 1-HMP was still 11 times higher in TA1538-SULT1A2*1Z than in TA1538-SULT1A2*2Y . Thus, differences in the properties between alloenzymes can lead to differences in the activation of promutagens . The model compounds were also tested in strains expressing the other ten human SULTs identified . Whereas OH-AAF and OH-APP showed the highest mutagenic activities in strains expressing SULT1A2, 1-HMP was more potent in strains expressing other SULT forms . With the limitation that little is known about the tissue distribution and regulation of SULT1A2, the findings suggest that its polymorphism may affect the individual susceptibility towards procarcinogens, in particular certain aromatic amines and amides . Arch Inst Pasteur Madagascar, 1996, 63(1-2), 67 - 75 {Street-vendor foods: quality of ice creams, sherbets and sorbets sold in the urban agglomeration of Antananarivo}; Ravaonindrina N et al.; A survey of selling conditions and bacteriological examinations of ice-cream was carried-out in Antananarivo from June 1996 to May 1997 . The way of investigation by vendors and of bacteriological examinations were widely described . Sellers had classic features of a street-vended food vendor: uneducated, no having professional training and mishandling foodstuffs . 202 samples of ice-cream were collected . The contamination prevalence rate was of 95% +/- 3.7% . Salmonella typhimurium was isolated from one sample . Immediate and rigourous measures ought to be put into effect by authorities to right this alarming situation. Clin Ther, 2002 Oct, 24(10), 1585 - 94 Results of a 5-year prospective surveillance study of antibiotic resistance among Salmonella enterica isolates and ceftriaxone therapy among children hospitalized for acute diarrhea; Chiappini E et al.; BACKGROUND: The spread of resistant Salmonella strains continues to increase worldwide . It is necessary to establish epidemiologic information to determine an appropriate empiric antibiotic regimen (when indicated) in infants and children with suspected Salmonella infections for whom the results of susceptibility tests are not yet available . OBJECTIVES: The aim of the present study was to investigate resistance rates and their modifications among Salmonella enterica strains isolated from Italian children hospitalized for acute diarrhea over 5 years . In addition, when antibiotic treatment was indicated, we assessed the in vivo success of parenteral ceftriaxone therapy . METHODS: This study included children admitted consecutively for acute diarrhea to the Division of Pediatrics and Infectious Diseases, Department of Pediatrics, University of Florence, Italy, from January 1, 1997, to December 31, 2001 . S enterica strains were isolated from stool cultures, biochemically identified, and serotyped . These isolates were tested by disk-diffusion assay, using the Kirby-Bauer method, for susceptibilities to ampicillin, ceftriaxone, ciprofloxacin, chloramphenicol, neomycin, tetracycline, and trimethoprim/sulfamethoxazole . The limits used for definition of resistance were those established by the guidelines of the National Committee for Clinical Laboratory Standards . RESULTS: A total of 2003 children (1051 boys, 952 girls; median age, 10.3 years; age range, 1 month-16.8 years) with acute diarrhea were admitted to the study . S enterica strains were isolated using stool cultures from 218 (10.9%) children (108 boys, 110 girls; median age, 3.3 years; age range, 2 months-15.8 years) . A total of 148 (67.9%) isolates were resistant to at least 1 antibiotic and 57 (26.1%) were multiresistant . The highest rates of resistance were those to tetracycline (132/218 {60.6%}), ampicillin (102/218 {46.8%}), and chloramphenicol (47/218 {21.6%}) . The lowest rate of resistance was to ceftriaxone (4/218 {1.8%}) . Overall, the rate of resistance to ciprofloxacin (19/218 {8.7%}) was significantly higher than that for ceftriaxone (P = 0.003) . Salmonella typhimurium (119/218 {54.6%}) and Salmonella enteritidis (62/218 {28.4%}) were the most frequently identified serotypes . Ceftriaxone was effective in vivo in all 56 children who required antibiotic therapy . CONCLUSIONS: There was a high prevalence of resistant S enterica strains . Ceftriaxone was used effectively in the treatment of S enterica infection in the population studied. Front Biosci, 2003 Jan 01, 8, d430 - 9 Transcription-driven DNA supercoiling and gene expression control; Chen CC et al.; DNA supercoiling plays important roles in gene expression regulation, although, the underlying mechanisms whereby DNA supercoiling modulates gene expression remain elusive . The fact that the transcription process itself generates DNA supercoiling has further complicated the issue . Transcription-driven DNA supercoiling is local and transient . Such a DNA supercoiling effect is likely to play important roles in controlling complex gene expression regulation . Using the suppression of the leu-500 mutation in Salmonella typhimurium topA mutants as a model system, we put forward our view of the effects of transcription-driven DNA supercoiling on gene expression control. Poult Sci, 2002 Nov, 81(11), 1653 - 60 Evaluation of aviguard, a commercial competitive exclusion product for efficacy and after-effect on the antibody response of chicks to Salmonella; Nakamura A et al.; The competitive exclusion (CE) action of Aviguard (AG) and its effects on the antibody response of chicks were evaluated in this study . We observed that AG protected the chicks from overwhelming colonization . Fourteen days after infection, fewer AG-pretreated than nonpretreated chicks shed salmonellae from their coloaca in both infected groups, although much less from SE-infected chicks . Antibody titers of sera produced to Salmonella typhimurium (ST) and SE in pretreated and non-pretreated chicks were not significantly different . Immunoblotting showed that these antibodies reacted with SDS-PAGE-separated 71.4, 67.7, 44.0, and 30.3 kDa proteins detectable in the test strains . Few weak bands of doubtful significance were observed in the cross-reaction between the sera of ST- and SE-infected chicks with ST and SE antigens, respectively . Our study showed that AG protected chicks from overwhelming colonization by salmonellae, and neither altered the antigenic proteins of infecting salmonellae nor their recognition by specific antibodies produced in response to the infection. Curr Drug Targets Infect Disord, 2001 Nov, 1(3), 287 - 302 Bacterial carriers and virus-like-particles as antigen delivery devices: role of dendritic cells in antigen presentation; Beyer T et al.; Replicating attenuated strains of intracellular bacteria like Salmonella typhimurium, Listeria monocytogenes or Mycobacterium bovis Bacille Calmette Guerin (BCG), and non-replicating virus-like-particles (VLP) consisting, for instance, of the VP1-surface component of polyoma virus offer great potential as heterologous carriers delivering foreign protein antigens for immune recognition . Moreover, attenuated S . typhimurium and L . monocytogenes strains hold also great promise as delivery vehicles for DNA vaccines . Polyoma virus-specific VLP consisting of VP1-pentamers are also of interest as carrier devices for eukaryotic expression plasmids . At first sight these different replicating and non-replicating types of vehicles have little in common, but from an immunological point of view viable bacteria and non-viable VLP are both well suited for evoking protective immune responses via several routes of vaccine administration . As these antigen carriers generate humoral and cell-mediated immunity, the heterologous antigens are not only targeted to appropriate pathways of major histocompatibility (MHC) class I and class II antigen processing and presentation, but also generate an adequate cytokine milieu for promoting antigen-specific responses . The most prominent advantage of these carrier devices is presented by their capacity to directly target antigenic proteins or DNA vaccines to immature dendritic cells (DC) along their maturation pathway . Mature DC are the key antigen presenting cell population which efficiently mediates antigen transport to organised lymphoid tissues for the initiation of T cell responses . In general, uptake of these diverse antigen delivery systems by antigen presenting cells (APC) finally lead to efficacious immune responses in the control of pathogenic microorganisms and tumours. Acta Crystallogr D Biol Crystallogr, 2002 Dec, 58(Pt 12), 2159 - 61 Epub 2002 Nov 23. Cloning, expression, purification and preliminary X-ray crystallographic studies of 2-methylisocitrate lyase from Salmonella typhimurium; Simanshu DK et al.; In Salmonella typhimurium, propionate is oxidized to pyruvate via the 2-methylcitric acid cycle . The last step of this cycle, the cleavage of 2-methylisocitrate to succinate and pyruvate, is catalysed by 2-methylisocitrate lyase (EC 4.1.3.30) . Methylisocitrate lyase (molecular weight 32 kDa) with a C-terminal polyhistidine affinity tag has been cloned and overexpressed in Escherichia coli and purified and crystallized under different conditions using the hanging-drop vapour-diffusion technique . Crystals belong to the orthogonal space group P2(1)2(1)2(1), with unit-cell parameters a = 63.600, b = 100.670, c = 204.745 A . A complete data set to 2.5 A resolution has been collected using an image-plate detector system mounted on a rotating-anode X-ray generator. Food Chem Toxicol, 2003 Jan, 41(1), 107 - 18 Effects of cis-nonachlor, trans-nonachlor and chlordane on the immune system of Sprague-Dawley rats following a 28-day oral (gavage) treatment; Tryphonas H et al.; The immunotoxicity of cis- and trans-nonachlor and chlordane were investigated in adult male and female Sprague-Dawley rats following a 28-day oral (gavage) treatment . Rats were randomly assigned to six experimental groups: cis-nonachlor, females; trans-nonachlor, females; technical chlordane females; cis-nonachlor, males; trans-nonachlor, males; technical chlordane, males . The immunologic endpoints included: quantification of the total serum immunoglobulin (Ig) levels and subclasses and flow cytometric analysis of peripheral blood leukocytes and T-lymphocyte subsets, evaluation of the lymphoproliferative activity of splenocytes in response to concanavalin A (Con A) and Salmonella typhimurium (STM) mitogens, and natural killer (NK) cell activity of splenocytes . Satellite experiments to examine the delayed-type hypersensitivity (DTH) response to oxazolone, and resistance to Listeria monocytogenes were set up for female rats treated with cis- or trans-nonachlor . Statistically significant (P<0.05) effects included: increased serum immunoglobulin M (IgM) levels in the chlordane-treated females at the 25 mg/kg dose (pairwise comparison); increased serum IgG(1) and IgG(2c) in the cis-nonachlor-treated males at the 2.5 and 25 mg/kg doses and increased serum IgG(2a) levels at all doses; increased serum IgG(2b) at the 25 mg/kg dose and decreased (dose-related) serum IgM levels in the cis-nonachlor-treated male rats; increased (linear trend) IgG(1) and IgG(2a) in the cis-nonachlor-treated females with effects on IgG(2a) significant at the 25 mg/kg dose compared with control; increased serum IgG(2a) in the trans-nonachlor-treated male and female rats at the 2.5 mg/kg dose; increased absolute numbers (linear trend) of peripheral white blood cells, B lymphocytes, natural killer (NK) cells, T-suppressor/cytotoxic lymphocytes, and the double positive (T-helper/inducer, T-suppressor/cytotoxic) cells in the trans-nonachlor-treated females; increased (non-linear trend) lymphoproliferative activity in the Con A-stimulated splenocytes and decreased (linear trend) activity in the S . typhimurium mitogen-stimulated splenocytes of the cis-nonachlor-treated females; reduced resistance to L . monocytogenes in the cis-nonachlor (day 3, P=0.034)- and trans-nonachlor (day 2, P=0.0001)-treated females, and reduced (linear trend) NK cell activity in the cis-nonachlor-treated males . The present data indicated that the chlordane compounds tested in this study had significant effects on a number of immunologic endpoints . In comparison to technical chlordane, cis- and trans-nonachlors were more immunotoxic . Therefore, an evaluation of the risk these chlorinated compounds may pose to human health should consider the potential effects different chlordane compounds may have on the immune system. Nucl Med Biol, 2002 Nov, 29(8), 849 - 53 Fluoro-A-85380 demonstrated no mutagenic properties in in vivo rat micronucleus and Ames tests; Valette H et al.; The potential mutagenic properties (micronucleus and the Ames tests) of fluoro-A-85380 (2-fluoro-3-{2(S)-2-azetidinylmethoxy}pyridine) were evaluated as a mandatory pre-clinical step . No statistically significant increase in the frequency of micronucleated polychromatic erythrocytes was found in animals treated at any dose tested . No biologically significant increase in the mean number of revertants was noted in all the Salmonella typhimurium strains tested with fluoro-A-85380 . Therefore, fluoro-A-85380 demonstrated no mutagenic properties using these two tests. Mol Microbiol, 2002 Dec, 46(5), 1451 - 64 Intestinal short-chain fatty acids alter Salmonella typhimurium invasion gene expression and virulence through BarA/SirA; Lawhon SD et al.; Salmonella typhimurium causes enteric and systemic disease by invading the intestinal epithelium of the distal ileum, a process requiring the invasion genes of Salmonella pathogenicity island 1 (SPI-1) . BarA, a sensor kinase postulated to interact with the response regulator SirA, is required for the expression of SPI-1 invasion genes . We found, however, that a barA null mutation had little effect on virulence using the mouse model for septicaemia . This confounding result led us to seek environmental signals present in the distal ileum that might supplant the need for BarA . We found that acetate restored the expression of invasion genes in the barA mutant, but had no effect on a sirA mutant . Acetate had its effect only at a pH that allowed its accumulation within the bacterial cytoplasm and not with the deletion of ackA and pta, the two genes required to produce acetyl-phosphate . These results suggest that the rising concentration of acetate in the distal ileum provides a signal for invasion gene expression by the production of acetyl-phosphate in the bacterial cytoplasm, a pathway that bypasses barA . We also found that a Delta(ackA-pta) mutation alone had no effect on virulence but, in combination with Delta(barA), it increased the oral LD50 24-fold . Thus, the combined loss of the BarA- and acetate-dependent pathways is required to reduce virulence . Two other short-chain fatty acids (SCFA), propionate and butyrate, present in high concentrations in the caecum and colon, had effects opposite to those of acetate: neither restored invasion gene expression in the barA mutant, and both, in fact, reduced expression in the wild-type strain . Further, a combination of SCFAs found in the distal ileum restored invasion gene expression in the barA mutant, whereas colonic conditions failed to do so and also reduced expression in the wild-type strain . These results suggest that the concentration and composition of SCFAs in the distal ileum provide a signal for productive infection by Salmonella, whereas those of the large intestine inhibit invasion. Antonie Van Leeuwenhoek, 2002 Aug, 81(1-4), 481 - 6 Defined competitive exclusion cultures in the prevention of enteropathogen colonisation in poultry and swine; Nisbet D; A competitive exclusion culture (CE) containing a mixture of 29 different bacterial isolates obtained from the cecae of broiler chickens was developed utilizing continuous-flow culture techniques . This culture (CF3) has been efficacious in controlling gut colonization by enteropathogens in both experimentally infected broilers and under commercial field conditions . In day-old broiler chicks provided CF3, and challenged with 10,000 CFU Salmonella typhimurium greater than a 99% reduction in Salmonella cecal colonization levels was observed compared to control chicks . Similarly, CF3 has also been shown to protect experimentally infected broiler chicks from cecal colonization by S . enteritidis (Phage types 4 and 13), S . gallinarum, Listeria Monocytogenes, and Escherichia coli O157:H7 . A commercial product was developed from CF3 and is sold under the tradename PREEMPT . In a Food and Drug Administration approved, double blinded, pivotal field trial, chicks treated with PREEMPTT' had significantly fewer salmonellae than untreated chicks at end-of-growout . This product is the first of its kind available to the U.S . poultry industry . Using similar technology a product has also been developed that decreases shedding of salmonellae in neonate and weaned pigs, and also has been shown to reduce mortality associated with enteropathogens in young pigs both in the laboratory and in a commercial swine herd. Biomed Mater Eng, 2002, 12(3), 225 - 37 A new porous titanium-nickel alloy: Part 1 . Cytotoxicity and genotoxicity evaluation; Assad M et al.; Porous titanium-nickel (PTN) alloys represent new biomaterials for long-term implantation . Their porosity properties might confer them the capacity to trigger fluid capillarity, tissue ingrowth, as well as good tissue-implant apposition and fixation . Before PTN materials are used as long-term implants, their biocompatibility level must be assessed . In this study, porous titanium-nickel was therefore extracted in a saline semi-physiological solution and materials were evaluated for potential cytotoxicity and genotoxicity reactions . The cytocompatibility elution test was performed in order to determine PTN toxic potential at the in vitro cellular level: no reactivity was detected in cell layers exposed to PTN extracts or the negative controls . In parallel, the genocompatibility of porous titanium-nickel was evaluated using three different assays in order to assess potential damage at the DNA level: the test for chemical induction of chromosome aberrations, the Salmonella typhimurium and Escherichia coli reverse mutation assay, and the mouse micronucleus test . No significant increase in the number of chromosomal aberrations, bacterian revertant colonies, or micronuclei was observed in presence of PTN extracts when compared to negative control exposition . Based on the above results, porous titanium-nickel can be considered completely cytocompatible and genocompatible, and therefore represents a good candidate for long-term implantation. Biosens Bioelectron, 2003 Jan, 18(1), 91 - 9 Impedance characterization of a piezoelectric immunosensor part II: Salmonella typhimurium detection using magnetic enhancement; Kim GH et al.; This study investigated the usefulness and characteristics of a 5-MHz quartz crystal resonator as a sensor of biological pathogens such as Salmonella typhimurium . An impedance analyzer measured the impedance behavior of the oscillating quartz crystal exposed to various concentrations of Salmonella (10(2)-10(8) cells per ml) . The Salmonella cells were captured by antibody-coated paramagnetic microspheres, and then these complexes were moved magnetically to the sensing quartz and were captured by antibodies immobilized on the crystal surface . The response of the crystal was expressed in terms of equivalent circuit parameters . The motional inductance and the motional resistance increased as a function of the concentration of Salmonella . The viscous damping was the main contributor to the resistance and the inductance in a liquid environment . The load resistance was the most effective and sensitive circuit parameter . A magnetic force was a useful method to collect the complexes of Salmonella-microspheres on the crystal surface and enhance the response of the sensor . In this system, the detection limit, based on resistance monitoring, was about 10(3) cells per ml. J Vet Sci, 2001 Dec, 2(3), 181 - 8 Multidrug-resistant Salmonella typhimurium and Salmonella enteritidis identified by multiplex PCR from animals; Yang SJ et al.; Antibiotic resistance in Salmonella enteritidis and S . typhimurium, one of most frequent etiologic pathogens of food-borne bacterial gastroenteritidis in humans, is a serious health problem worldwide . Fifteen and 22 each of S . enteritidis and S . typhimurium were isolated from animals from 1983 to 1999 in Korea and tested for their antibiotic resistance patterns and phage types . S . enteritides isolates were highly resistant to sulfonamides (86.7%) and four of them (26.6%) showed multiple antibiotic resistance . The most frequent phage type (PT) of S . enteritids was PT1 (33.3%) even though none of them had multiple antibiotic resistance . S . typhimurium isolates were highly resistant to streptomycin, sulfonamides, and tetracycline, 100%, 95.5%, and 86.4% respectively . The incidence of multiple antibiotic resistance of S . typhimurium isolates was extremely high (100%) comparing to S . enteritidis isolates (26.7%) . Two of the five ACSSuT type S . typhimurium isolates, resistant to ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracycline, were phage type DT104 . All S . typhimurium isolates were sensitive to florfenicol . For the rapid detection of multiple antibiotic resistant S . enteritidis and S . typhimurium isolates, particularly ACSSuT type S . typhimurium DT104, antibiotic resistance genes, cmlA/tetR, PSE-1, and TEM, and Salmonella spp . Specific gene, SipB/C, were amplified using four pairs of primers in hot-started multiplex polymerase chain reaction . Two Korean isolates of S . typhimurium DT104 showed TEM amplicons instead of PSE-1 for the ampicillin resistance . The multiplex PCR used in this study was useful in rapid detection of ACSSuT type S . typhimurium and identification of b-lactamase gene distribution among Salmonella isolates. Proc Natl Acad Sci U S A, 2002 Nov 26, 99(24), 15705 - 10 Epub 2002 Nov 19. Host-pathogen interactions: Host resistance factor Nramp1 up-regulates the expression of Salmonella pathogenicity island-2 virulence genes; Zaharik ML et al.; Nramp1 (Natural resistance-associated macrophage protein-1; also known as Slc11a1) is a host resistance gene that provides protection against several intracellular pathogens, including Salmonella enterica serovar Typhimurium . Little is known about the dynamic interplay that occurs between mammalian host resistance determinants such as Nramp1 and pathogens during infection . To explore these interactions, we examined the effect of Nramp1 on expression of Salmonella typhimurium (STM) virulence factors . We demonstrate that Salmonella pathogenicity island 2 (SPI2) is essential for replication of STM in spleens of infected Nramp1(+/+) mice . Furthermore, the presence of Nramp1 in transfected cell lines and congenic knockout mice resulted in the up-regulation of STM SPI2-associated virulence genes critical for intramacrophage survival . This Nramp1-dependent up-regulation of SPI2 was mimicked in vitro by chelation of iron, demonstrating the iron-responsive nature of expression of STM SPI2-associated virulence genes . We propose that acquisition of SPI2 by S . enterica not only enabled this bacterium to become an effective intracellular pathogen but also allowed the bacterium to withstand the effects of macrophage defense mechanisms such as Nramp1 early in the evolution of its pathogenic character . These dynamic Nramp1-pathogen interactions may be essential for regulating the course of an infection . This study demonstrates the presence of a previously undescribed direct influence of a mammalian innate host resistance locus on a pathogen at the genetic level. Mutat Res, 2002 Nov 26, 521(1-2), 19 - 27 Mutagenic activity of structurally related oxiranes and siloranes in Salmonella typhimurium; Schweikl H et al.; Ring-opening molecules like oxiranes (epoxides) maybe suitable for the development of non-shrinking dental composite materials . Since oxiranes are reactive molecules, they can cause adverse biological effects in living organisms . The introduction of siloranes, a merger of silane and oxirane, may solve this problem . Here, new oxiranes and siloranes were analyzed for the induction of mutations in Salmonella typhimurium (TA97a, TA98, TA100, and TA102), and a reactive oxirane molecule served as a reference . This chemical, epoxy cyclohexyl methyl-epoxy cyclohexane carboxylate (Est-Ep) tested positive in S . typhimurium TA100 . The numbers of mutants were about 3-10-fold higher than controls in the presence of a metabolically active S9 fraction isolated from rat liver . Only a weak mutagenic effect was observed after direct testing (without S9) . Di(cyclohexene-epoxidemethyl)ether (Eth-Ep) also caused a slight increase of mutant numbers in TA100 both in the presence and absence of S9 . In contrast, no effects were detected with the large oxirane molecules, 2,2-bis(4,1-phenylenoxy-3,1-propanediyl-3-oxatricyclo {3.2.1.0(2,4)}octylcarboxy) propylidene (Nor-BP-Ep) and 2,2-bis(4,1-phenylenoxy-3,1-propanediyl-3,4-epoxycyclo-hexylcarboxylic-acid) propylidene (Est-BP-Ep) . As to the siloranes, 1,4-bis(2,3-epoxypropyloxypropyl-dimethylsilyl)-benzene (Phen-Glyc) was a direct mutagen in S . typhimurium TA100 and TA102 . This weak but dose-related increase of revertants was even enhanced by S9 . Other siloranes, like di-3,4-epoxy cyclohexylmethyl-dimethyl-silane (DiMe-Sil), methyl-bis{2-(7-oxabicyclo{4.1.0}hept-3-yl)phenyl silane (Ph-Sil), and 1,3,5,7-tetrakis(ethyl cyclohexane epoxy)-1,3,5,7-tetramethyl-cyclotetrasiloxane (TET-Sil) tested negative in all S . typhimurium strains . All compounds will be further analyzed for the formation of chromosomal aberrations in mammalian cell cultures. Biomaterials, 2003 Feb, 24(4), 611 - 7 Effect of sample preparation on the in vitro genotoxicity of a light curable glass ionomer cement; Muller BP et al.; The glass ionomer cement Vitrebond showed a clear genotoxic effect in the in vitro Mammalian Cell Gene Mutation Test (HPRT Test) with CHO cells as well as in the bacterial umu-test with Salmonella typhimurium TA1535/pSK1002 . Both DMSO and Ham's F12 cell culture medium extracts according to ISO 10993-12 (Biological evaluation of medical devices-Part 12: sample preparation and reference materials, Geneva, Switzerland) exhibit a clear genotoxic effect in the umu-test . The effect is independent of the extraction volume in a range from 0.5 to 4 ml Ham's F12 cell culture medium . Subsequent extractions of Vitrebond showed no significant difference in the genotoxic response although weight loss and content of 2-hydroxyethyl-methacrylate dropped significantly . In vivo conditions of Vitrebond were simulated by extractions with artificial and collected human saliva . These extracts showed a clear genotoxic effect in the umu-test, even if only a few seconds of extraction time were applied . In conclusion, sample preparations for genotoxicity testing according to ISO 10993-12 reflect the in vivo conditions of Vitrebond applications . This seems to be mostly due to the hydrophilic nature of the genotoxic ingredients. Structure (Camb), 2002 Nov, 10(11), 1569 - 80 Structural studies of Salmonella typhimurium ArnB (PmrH) aminotransferase: a 4-amino-4-deoxy-L-arabinose lipopolysaccharide-modifying enzyme; Noland BW et al.; Lipid A modification with 4-amino-4-deoxy-L-arabinose confers on certain pathogenic bacteria, such as Salmonella, resistance to cationic antimicrobial peptides, including those derived from the innate immune system . ArnB catalysis of amino group transfer from glutamic acid to the 4"-position of a UDP-linked ketopyranose molecule to form UDP-4-amino-4-deoxy-L-arabinose represents a key step in the lipid A modification pathway . Structural and functional studies of the ArnB aminotransferase were undertaken by combining X-ray crystallography with biochemical analyses . High-resolution crystal structures were solved for two native forms and one covalently inhibited form of S . typhimurium ArnB . These structures permitted identification of key residues involved in substrate binding and catalysis, including a rarely observed nonprolyl cis peptide bond in the active site. Avian Pathol, 2002 Feb, 31(1), 41 - 7 Quantitative comparison of intestinal invasion of zoonotic serotypes of Salmonella enterica in poultry; Aabo S et al.; The aim of the present study was to compare the invasion of selected zoonotic Salmonella serotypes of poultry in an in vivo chicken intestinal loop model and also in vitro in epithelial cell cultures . Invasion was measured relative to a reference strain, Salmonella Typhimurium 4/74 invH201::TnphoA . Two serotypes demonstrated intracellular log(10) counts that differed significantly from all other serotypes tested: Salmonella Enteritidis PT4 being 1.5 log(10) colony forming units (CFU) (31-fold) higher, and Salmonella Tennessee being 0.7 log(10) CFU (fivefold) lower than the reference strain (P < or = 0.0001) . A group of serotypes, which can be vertically transmitted, showed significantly higher intracellular counts (fourfold to eightfold) than the reference strain . The group included S . Typhimurium 4/74, S . Typhimurium DT104 (poultry and porcine isolates), S . Enteritidis PT1, S . Enteritidis PT6, S . Enteritidis PT8, and Salmonella Berta . The serotypes Salmonella Hadar, Salmonella Virchow, S . 4,12:b:-, S . Typhimurium DT41, and Salmonella Infantis, most of which are considered horizontally transmitted, did not show significantly different intracellular counts from the reference strain . Results from the cell culture invasion studies agreed with the in vivo data, with the exception of S . Berta and the poultry isolate of S . Typhimurium DT104. J Chemother, 2002 Aug, 14(4), 346 - 50 Antimicrobial-resistant Salmonella enterica serovars isolated from chickens in Spain; Hernandez T et al.; In order to analyze the antibiotic resistance of Salmonella enterica serovars, a total of 112 Salmonella strains were tested (54 S . enteritidis, 32 S . typhimurium, 11 S . heidelberg, 7 S . infantis, 4 S . virchow and 4 S . hadar) . The bacteria were isolated from 691 samples of frozen and fresh chicken meat . Identification of microorganisms and antimicrobial sensitivity testing were undertaken by means of the automated MicroScan AutoScan 4 method (Baxter in Spain) . 45.5% of 112 strains tested were susceptible to all antibiotics . The highest percentage of resistance was found to: chloramphenicol (44.6%), ampicillin (34.8%) and tetracycline (33.9%) . Multiple resistance was observed in 49 strains (43.7%), whereas single resistance was seen in 12 isolates (10.7%) . We found 12 different patterns of resistance in Salmonella enterica serovar enteriditis . Resistance to chloramphenicol was the most common single resistance . The most frequent patterns of multiresistant strains were ampicillin + amoxicillin/clavulanate + cefazolin + imipenem and chloramphenicol + impipenem . In this serotype, 49 isolates belonged to phagetype 4 . Salmonella typhimurium showed the highest percentages of resistance to the tested drugs, with six different resistance patterns found . 25 strains out of 32 S . typhimurium isolates belonged to phagotype 120 and 13 of these showed the same resistance pattern: chloramphenicol + tetracycline + ampicillin . The high incidence of antibiotic resistant salmonellae found in chickens in our study suggests the need for public health interventions to decrease selective pressure on bacterial strains by antimicrobial agents. Carcinogenesis, 2002 Nov, 23(11), 1937 - 45 Metabolic activation of the environmental contaminant 3-nitrobenzanthrone by human acetyltransferases and sulfotransferase; Arlt VM et al.; 3-Nitrobenzanthrone (3-NBA) an extremely potent mutagen and suspected human carcinogen identified in diesel exhaust and in airborne particulate matter was shown to form multiple DNA adducts in vitro and in vivo in rats . In order to investigate whether human N,O-acetyltransferases (NATs) and sulfotransferases (SULTs) contribute to the metabolic activation of 3-NBA we used a panel of newly constructed Chinese hamster lung fibroblast V79MZ derived cell lines expressing human NAT1, human NAT2 or human SULT1A1, as well as TA1538-derived Salmonella typhimurium strains expressing human NAT1 (DJ400) or human NAT2 (DJ460) and determined DNA binding and mutagenicity . The formation of 3-NBA-derived DNA adducts was analysed by (32)P-postlabelling after exposing V79 cells to 0.01 micro M 3-NBA or 0.1 micro M N-acetyl-N-hydroxy-3-aminobenzanthrone (N-Ac-N-OH-ABA), a potential metabolite of 3-NBA . Similarly up to four major and two minor adducts were detectable for both compounds, the major ones being identical to those detected previously in DNA from rats treated with 3-NBA . Comparison of DNA binding between different V79MZ derived cells revealed that human NAT2 and, to a lesser extent, human NAT1 and human SULT1A1, contribute to the genotoxic potential of 3-NBA and N-Ac-N-OH-ABA to form DNA adducts . However, the extent of DNA binding by 3-NBA was higher in almost all V79 cells at a 10-fold lower concentration than by N-Ac-N-OH-ABA, suggesting that N-Ac-N-OH-ABA is not a major intermediate in the formation of 3-NBA-derived adducts . 3-NBA showed a 3.8-fold and 16.8-fold higher mutagenic activity in Salmonella strains expressing human NAT1 and human NAT2, respectively, than in the acetyltransferase-deficient strain, whereas N-Ac-N-OH-ABA was only clearly (but weakly) mutagenic in Salmonella DJ460 expressing human NAT2 . This finding suggests that N-Ac-N-OH-ABA is not a major reactive metabolite responsible for the high mutagenic potency of 3-NBA in Salmonella . Collectively our results indicate that O-acetylation and O-sulfonation by human NATs and SULTs may contribute significantly to the high mutagenic and genotoxic potential of 3-NBA . Moreover, the yet-unidentified four major 3-NBA-derived adducts may be DNA adducts without an N-acetyl group. J Biotechnol, 2003 Jan 9, 100(1), 1 - 12 Antimicrobial properties of the Escherichia coli R1 plasmid host killing peptide; Pecota DC et al.; The 52 amino acid host killing peptide (Hok) from the hok/sok post-segregational killer system of the Escherichia coli plasmid R1 was synthesized using Fmoc (9-fluorenylmethoxycarbonyl) chemistry, and its molecular weight was confirmed by mass spectroscopy . Hok kills cells by depolarizing the cytoplasmic membrane when it is made in the cytosol . Six microorganisms, E . coli, Bacillus subtilis, Pseudomonas aeruginosa, P . putida, Salmonella typhimurium, and Staphylococcus aureus were exposed to the purified peptide but showed no significant killing . However, electroporation of Hok (200 microgml(-1)) into E . coli cells showed a dramatic reduction (100000-fold) in the number of cells transformed with plasmid DNA which indicates that the synthetic Hok peptide killed cells . Electroporation of Hok into P . putida was also very effective with a 500-fold reduction in electrocompetent cells (100 microgml(-1)) . Heat shock in the presence of Hok (380 microgml(-1)) resulted in a 5-fold reduction in E . coli cells but had no effect on B . subtilis . In addition, three Hok fragments (Hok(1-28), Hok(31-52) and Hok(16-52)) killed cells when electroporated into E . coli at 200 microgml(-1) (over 1000-fold killing for Hok(1-28), 50-fold killing for Hok(16-52) and over 1000-fold killing for Hok(31-52)) . E . coli cells electroporated with Hok and visualized using transmission electron microscopy showed the same morphological changes as control cells to which Hok was induced using a plasmid inside the cell. Poult Sci, 2002 Oct, 81(10), 1598 - 605 Comparison of electrolyzed oxidizing water with various antimicrobial interventions to reduce Salmonella species on poultry; Fabrizio KA et al.; Foodborne pathogens in cell suspensions or attached to surfaces can be reduced by electrolyzed oxidizing (EO) water; however, the use of EO water against pathogens associated with poultry has not been explored . In this study, acidic EO water {EO-A; pH 2.6, chlorine (CL) 20 to 50 ppm, and oxidation-reduction potential (ORP) of 1,150 mV}, basic EO water (EO-B; pH 11.6, ORP of -795 mV), CL, ozonated water (OZ), acetic acid (AA), or trisodium phosphate (TSP) was applied to broiler carcasses inoculated with Salmonella Typhimurium (ST) and submerged (4 C, 45 min), spray-washed (85 psi, 25 C, 15 s), or subjected to multiple interventions (EO-B spray, immersed in EO-A; AA or TSP spray, immersed in CL) . Remaining bacterial populations were determined and compared at Day 0 and 7 of aerobic, refrigerated storage . At Day 0, submersion in TSP and AA reduced ST 1.41 log10, whereas EO-A water reduced ST approximately 0.86 log10 . After 7 d of storage, EO-A water, OZ, TSP, and AA reduced ST, with detection only after selective enrichment . Spray-washing treatments with any of the compounds did not reduce ST at Day 0 . After 7 d of storage, TSP, AA, and EO-A water reduced ST 2.17, 2.31, and 1.06 log10, respectively . ST was reduced 2.11 log10 immediately following the multiple interventions, 3.81 log10 after 7 d of storage . Although effective against ST, TSP and AA are costly and adversely affect the environment . This study demonstrates that EO water can reduce ST on poultry surfaces following extended refrigerated storage. Mol Microbiol, 2002 Oct, 46(2), 355 - 66 Compensatory adaptation to the deleterious effect of antibiotic resistance in Salmonella typhimurium; Maisnier-Patin S et al.; Most chromosomal mutations that cause antibiotic resistance impose fitness costs on the bacteria . This biological cost can often be reduced by compensatory mutations . In Salmonella typhimurium, the nucleotide substitution AAA42 --> AAC in the rpsL gene confers resistance to streptomycin . The resulting amino acid substitution (K42N) in ribosomal protein S12 causes an increased rate of ribosomal proofreading and, as a result, the rate of protein synthesis, bacterial growth and virulence are decreased . Eighty-one independent lineages of the low-fitness, K42N mutant were evolved in the absence of antibiotic to ameliorate the costs . From the rate of fixation of compensated mutants and their fitness, the rate of compensatory mutations was estimated to be > or = 10-7 per cell per generation . The size of the population bottleneck during evolution affected fitness of the adapted mutants: a larger bottleneck resulted in higher average fitness . Only four of the evolved lineages contained streptomycin-sensitive revertants . The remaining 77 lineages contained mutants that were still fully streptomycin resistant, had retained the original resistance mutation and also acquired compensatory mutations . Most of the compensatory mutations, resulting in at least 35 different amino acid substitutions, were novel single-nucleotide substitutions in the rpsD, rpsE, rpsL or rplS genes encoding the ribosomal proteins S4, S5, S12 and L19 respectively . Our results show that the deleterious effects of a resistance mutation can be compensated by an unexpected variety of mutations. Epidemiol Infect, 2002 Oct, 129(2), 287 - 93 The use of sequential studies in a salmonellosis outbreak linked to continental custard cakes; Ward B et al.; We investigated an outbreak of 54 cases of Salmonella Typhimurium phage type 9 (STM9) with a specific antibiotic resistance pattern . We used sequential analytic studies: two retrospective cohort studies, a case-control study, and a modified case-control study . An outbreak of salmonellosis due to Salmonella Typhimurium PT9 SSu (resistant to streptomycin and sulphafurazole) was identified . Fifty-four cases had illness onset from November 1998 to March 1999 . Notifications commenced following a restaurant birthday party in December 1998 . An initial cohort and case control study found no association with consumption of custard cake . However, case follow-up identified another cohort of people who had attended a birthday party in February at which 8/27 people who consumed a continental custard cake were ill compared to 0/10 who did not (P = 0.07) . A revised case control study found illness was strongly associated with consumption of a particular continental custard cake (Mantel-Haenszel matched OR infinity, P = 0.00004) . This report highlights the epidemiological value of using sequential study types, and persisting with the investigation of apparently sporadic food-borne outbreaks. Curr Microbiol, 2002 Dec, 45(6), 456 - 8 Cloning and expression of Chlorobium vibrioforme uroporphyrinogen decarboxylase gene in a Salmonella heme auxotroph; Xu K et al.; To study the post-uroporphyrin steps in heme and chlorophyll biosynthesis in Chlorobium, we attempted to clone the uroporphyrinogen decarboxylase ( hemE) gene . A Chlorobium genomic library was used to transform a restriction-minus Salmonella typhimurium strain . The recombinant DNA molecules were transduced into an auxotrophic Salmonella double mutant ( hemA(-) hemE(-)) by phage P22 . Faster-growing colonies indicated complementation of the hemE mutation . Each clone was tested by backcross transduction of the mutant . Growth rates of the confirmed clones in LB medium were comparable to wild-type Salmonella . HPLC analysis of the substrate (uroporphyrinogen) and the product (coproporphyrinogen) of the decarboxylase activity was performed in one such clone . This clone showed an active hemE gene within a 4-kb insert. Blood, 2003 Jan 15, 101(2), 649 - 54 Epub 2002 Sep 12. Immunotherapy with a posttranscriptionally modified DNA vaccine induces complete protection against metastatic neuroblastoma; Pertl U et al.; The successful induction of a T-cell-mediated tumor-protective immunity against poorly immunogenic malignancies remains a major challenge for cancer immunotherapy . We achieved this by immunization with a tyrosine hydroxylase (mTH)-based DNA vaccine, enhanced with the posttranscriptional regulatory acting RNA element (WPRE), derived from woodchuck hepatitis virus in combination with an antibody-cytokine fusion protein (ch14.18-IL-2) that targets interleukin-2 (IL-2) to the tumor microenvironment . This DNA vaccine mTH-WPRE was carried by attenuated Salmonella typhimurium and applied by oral gavage in a mouse model of neuroblastoma . Mice immunized with the mTH-WPRE vaccine, and which additionally received a boost with suboptimal doses of ch14.18-IL-2, were completely protected against hepatic neuroblastoma metastases . In contrast, all controls presented with disseminated metastases . Both T-cell and natural killer (NK) cell-dependent mechanisms were involved in the induction of a systemic tumor-protective immunity . Thus, up-regulation of interferon-gamma (IFN-gamma) expression in CD8(+) T cells occurred only in those animals that received the mTH-WPRE vaccine plus the ch14.18-IL-2 boost . Up-regulation of this proinflammatory cytokine was not observed in mice immunized with mTH-WPRE vaccine alone . A role for NK cells was indicated by the complete abrogation of systemic tumor-protective immunity in all animals that were depleted of NK cells in vivo . Taken together, these data demonstrate that immunization with a posttranscriptionally enhanced DNA vaccine encoding the WPRE sequence, combined with a boost of the ch14.18-IL-2 fusion protein, completely protects against hepatic metastases in a murine model of neuroblastoma and therefore may lead to a new strategy for immunotherapy and prevention of metastatic neuroblastoma. Chem Res Toxicol, 2002 Oct, 15(10), 1288 - 94 Structure of DNA adduct formed with aminophenylnorharman, being responsible for the comutagenic action of norharman with aniline; Totsuka Y et al.; A mutagenic heterocyclic amine (HCA), 9-(4'-aminophenyl)-9H-pyrido{3,4-b}indole (aminophenylnorharman, APNH), is produced in the presence of S9 mix by the reaction of norharman and aniline, both of which are nonmutagenic and abundantly present in our environment . It has been previously reported that APNH-DNA adducts were detected in DNA of Salmonella typhimurium strain incubated with APNH and S9 mix . In the present study, we examined the structures of APNH-DNA adducts using the (32)P-postlabeling method and various spectrometry techniques . When the reaction mixture of N-acetoxy-APNH and 2'-deoxyguanosine 3'-monophosphate (3'-dGp) was analyzed, three adduct spots (two major and one minor) were observed by (32)P-postlabeling under modified-standard conditions . No adduct formation was observed for reaction mixtures of N-acetoxy-APNH with 3'-dAp, 3'-dTp, or 3'-dCp . The two major adduct spots (spots 1 and 2) detected by TLC were extracted and subjected to HPLC along with the standards 3',5'-pdGp-C8-APNH and 5'-pdG-C8-APNH, which were independently chemically synthesized . On the basis of the results of co-chromatography, spots 1 and 2 were identified to be 5'-monophosphate and 3',5'-diphosphate forms of dG-C8-APNH . When the extract of spot 2 (3',5'-pdGp-C8-APNH) was further digested with nuclease P1 and phosphodiesterase I, a spot corresponding to spot 1 (5'-pdG-C8-APNH) was newly observed on TLC . From these observations, both of the two major spots were concluded to be dG-C8-APNH . A similar DNA adduct pattern to that apparent in vitro was observed in various organs of F344 rats fed 40 ppm of APNH for 4 weeks . The levels of APNH-DNA adducts were highest in the liver and colon, with RAL values of 1.31 +/- 0.26 and 1.32 +/- 0.11 adducts/10(7)nucleotides, respectively . Thus, APNH was demonstrated to form DNA adducts primarily at the C-8 position of guanine residues in vitro and in vivo, like other mutagenic and carcinogenic HCAs. Food Chem Toxicol, 2002 Oct, 40(10), 1475 - 82 Antimutagenic activities of acetone and methanol fractions of Terminalia arjuna; Kaur K et al.; The antimutagenic effect of benzene, chloroform, acetone and methanol fractions from Terminalia arjuna, a well-known medicinal plant, was determined against Acid Black dye, 2-aminofluorene (2AF) and 4-nitro-o-phenylenediamine (NPD) in TA98 Frameshift mutagen tester strain of Salmonella typhimurium . Among the different fractions, the antimutagenic effect of acetone and methanol fractions was more than that observed with other fractions . Co-incubation and pre-incubation modes of experimentation did not show much difference in the antimutagenic activity of the extracts . Moreover, these fractions inhibited the S9-dependent mutagens, 2AF and Acid Black dye more effectively than the direct-acting mutagens . Studies are under way to isolate and elucidate the nature of the antimutagenic factor in acetone and methanol fractions. Nippon Eiseigaku Zasshi, 2002 Sep, 57(3), 547 - 55 {Low dose exposure to cadmium and its health effects (1) . Genotoxicity and carcinogenicity}; Koyama H et al.; We reviewed studies on genotoxicity and carcinogenicity of cadmium (Cd) . Salmonella typhimurium and Escherichia coli exposed to Cd did not show mutagenicity, whereas cultured mammalian cells exposed to Cd showed mutation, DNA strand breaks, and chromosomal aberrations . Carcinogenicity tests showed that exposure to Cd increased the occurrence of tumors in testis, lung, prostate, hematopoietic tissues, and injection sites . On the other hand, recent epidemiologic studies are not supportive of earlier observations on the association between Cd and prostate cancer . The US NIOSH data on a possible association between Cd and lung cancer may need reevaluation . No studies which show a positive relationship between oral Cd exposure and carcinogenesis have been reported . All available data suggest that Cd should be reassigned to IARC Group 2A (probably carcinogenic to humans) from the current Group 1. J Surg Res, 2002 Sep, 107(1), 101 - 7 Liver and circulating NK1.1(+)CD3(-) cells are increased in infection with attenuated Salmonella typhimurium and are associated with reduced tumor in murine liver cancer; Feltis BA et al.; An attenuated (DeltacyA, Deltacrp) strain of Salmonella typhimurium (chi4550) containing a gene for human IL-2 (chi4550pIL2) reduces hepatic tumor burden when orally inoculated into mice with liver cancer; however, wild-type S . typhimurium is also associated with cancer regression . Therefore, experiments were designed to clarify the invasiveness and the anti-tumor properties of three strains of S . typhimurium . S . typhimurium chi4550pIL2, chi4550, or wild type (WT) was incubated with mature Caco-2 and HT-29 enterocytes, and S . typhimurium internalization was assessed . For infectivity experiments, mice were orally inoculated with saline or 10(9)S . typhimurium chi4550pIL2, chi4550, or WT; 48 h later mice were sacrificed for analysis of cecal bacteria and S . typhimurium translocation to mesenteric lymph nodes . For experiments involving tumor implantation, four groups were studied: saline control, tumor alone, chi4550pIL2+tumor, and chi4550+tumor . Mice were orally inoculated with saline or S . typhimurium and underwent laparotomy 24 h later with 5 x 10(4) MCA38 murine adenocarcinoma cells injected into the spleen . On day 14, liver tumors were counted and peripheral blood and hepatic lymphocyte populations were analyzed by FACScan . Attenuated S . typhimurium exhibited decreased internalization by cultured enterocytes and decreased infectivity after oral inoculation . Mice treated with chi4550pIL2 or chi4550 had fewer liver tumors and increased populations of hepatic and circulating NK1.1(+)CD3(-) lymphocytes compared to mice treated with saline (P < 0.01) . These data suggest that attenuated S . typhimurium may have an application as an anti-tumor agent. Regul Toxicol Pharmacol, 2002 Aug, 36(1), 69 - 79 The toxicity of behenyl alcohol . I . Genotoxicity and subchronic toxicity in rats and dogs; Iglesias G et al.; The genotoxic potential of behenyl alcohol, a saturated long-chain (C22:0) fatty alcohol, was examined in the Ames Salmonella typhimurium reverse mutation assay, the gene mutation, and chromosome aberrations assays in Chinese hamster V79 cells, and the micronucleus assay in NMRI mice . Behenyl alcohol did not increase the number of revertants per plate compared to controls in the S . typhimurium assay, with or without metabolic activation . No significant increases in the number of mutant colonies or in structural chromosome aberrations were observed in Chinese hamster V79 cells . In addition, behenyl alcohol did not increase the frequency of bone marrow polychromatic erythrocyte (PCE) micronuclei in mice in vivo . In two subchronic toxicity studies, CD rats and beagle dogs were administered behenyl alcohol by oral gavage for at least 26 weeks at doses of 0, 10, 100, or 1000 mg behenyl alcohol/kg body weight/day for rats and 0, 20, 200, or 2000 mg behenyl alcohol/kg body weight/day for dogs . Adverse effects were not observed following gross and histopathological evaluations of dosed rats . Compound-related effects in dogs were limited to observations of pale feces, indicative of unabsorbed behenyl alcohol, at doses of 2000 mg/kg body weight/day . There were no histopathological changes observed in dogs dosed with behenyl alcohol . The no-observed-adverse-effect-level (NOAEL) for behenyl alcohol was 1000 mg/kg body weight/day for rats, and 2000 mg/kg body weight/day for dogs, the highest doses used in these studies. J Biol Chem, 2002 Dec 27, 277(52), 51025 - 32 Epub 2002 Oct 14. Cdc42 and Rac1 regulate late events in Salmonella typhimurium-induced interleukin-8 secretion from polarized epithelial cells; Hobert ME et al.; Salmonella typhimurium colonization of the intestinal epithelium initiates biochemical cross-talk between pathogen and host that results in the secretion of chemokines, such as interleukin (IL)-8, that direct neutrophil migration to the site of infection . In nonpolarized cells, Rac1 and Cdc42 have been shown to regulate both bacterial invasion and signaling events leading to nuclear responses and IL-8 secretion . However, because the underlying actin cytoskeleton and the associated signaling machinery are distributed much differently in polarized epithelial cells, we used polarized Madin-Darby canine kidney monolayers to investigate the role of Rac1 and Cdc42 in S . typhimurium-induced pro-inflammatory responses in the more physiologically relevant polarized state . In Madin-Darby canine kidney monolayers expressing dominant-negative Rac1 or Cdc42, both Salmonella- and tumor necrosis factor alpha-induced activation of NFkappaB and mitogen-activated protein kinase signaling cascades proceeded normally, but IL-8 secretion was inhibited . We found that Rac1 and Cdc42 were not involved in early pro-inflammatory signaling events, as in nonpolarized cells, but rather regulated the basolateral exocytosis and secretion of IL-8 . In contrast, dominant-negative Rac1 inhibited apical actin pedestal formation, indicating that pedestal formation and nuclear signaling for pro-inflammatory activation are not linked . These findings indicate that there are significant differences in the requirements of pathogen-induced host cell signaling pathways in polarized and nonpolarized cells. Int J Food Microbiol, 2003 Jan 25, 80(2), 153 - 9 Salmonella DNA adenine methylase mutants prevent colonization of newly hatched chickens by homologous and heterologous serovars; Dueger EL et al.; Salmonella mutants lacking DNA adenine methylase (Dam) are highly attenuated for virulence and confer protection against oral challenge with homologous and heterologous Salmonella serovars in mice and chicken broilers . To determine whether vaccines based on Dam are efficacious in preventing early colonization of newly hatched chickens, a Salmonella typhimurium Dam(-) vaccine was evaluated for the protection of chicks against oral challenge with homologous and heterologous Salmonella serovars . Vaccination of chicks elicited protection 2 and 6 days post-challenge as evidenced by a significant reduction in colonization of the gastrointestinal tract (ileum, cecum and feces) and visceral organs (spleen and bursa) when challenged with homologous S . typhimurium . Moderate protection was observed following challenge with heterologous S . enteritidis and Salmonella O6, 14, 24:e, h-monophasic) serovars . These data suggest that Salmonella Dam mutant strains conferred cross-protection, presumably via competitive exclusion mechanisms that prevent superinfection of chicks by other Salmonella strains . Such protection may reduce pre-harvest Salmonella contamination in poultry, decreasing the potential for food-borne transmission of this pathogen to humans. Mutat Res, 2002 Oct 31, 508(1-2), 147 - 56 Inhibition of human cytochrome P450 1B1, 1A1 and 1A2 by antigenotoxic compounds, purpurin and alizarin; Takahashi E et al.; Recently we have shown that anthraquinone food pigments such as purpurin and alizarin suppress the genotoxic activities of several mutagens including heterocyclic amines and polycyclic aromatic hydrocarbons in the Drosophila DNA repair test and in the Ames test . To investigate the mechanism of this inhibition, we have now examined the effects of these anthraquinone pigments on enzymes that metabolize xenobiotics . The activities of eight human recombinant cytochrome P450 (CYP) isozymes were measured in the presence of purpurin, alizarin or carminic acid . Purpurin and alizarin strongly inhibited the activities of CYP1A1, CYP1A2 and CYP1B1, and weakly suppressed those of CYP2A6 and CYP2E1 in a dose-dependent manner, but did not inhibit those of CYP2C19, CYP3A4 and CYP3A5 . Carminic acid did not affect the activities of any CYPs tested . CYP1B1 was the most strongly affected CYP molecule by purpurin and alizarin among CYPs examined in this study . From kinetic analysis, it was shown that the inhibition by purpurin on CYP1B1 was both competitive and non-competitive, and that by alizarin was competitive . The values of slopes obtained from Lineweaver-Burk plots are proportional to the square of purpurin concentration . This observation suggests that two molecules of purpurin are interacting with one molecule of CYP1B1 . The K(m) value of CYP1B1 was 11 microM, and the K(i) value of purpurin and alizarin against CYP1B1 was 0.7 microM(2) and 0.5 microM, respectively . We also examined the effects of these pigments on the mutagenicities of MeIQx and B{a}P in the Ames test, using Salmonella typhimurium TA1538 co-expressing each form of human CYP and NADPH-cytochrome P450 reductase (OR) . The mutagenicity of MeIQx in TA1538 1A2/OR or 1B1/OR was suppressed by purpurin and alizarin but not by carminic acid . Purpurin also reduced the mutagenicity of B{a}P in TA1538 1A1/OR or 1B1/OR . These results suggest that the antigenotoxic activities of purpurin and alizarin can be explained by inhibition of CYP activities responsible for activating the mutagens. J Leukoc Biol, 2002 Oct, 72(4), 743 - 51 Salmonella virulence factor SipB induces activation and release of IL-18 in human dendritic cells; Dreher D et al.; Interleukin-18 (IL-18) plays an important role in innate and acquired immunity, in particular against intracellular pathogens . However, little is known about the microbial factors that trigger IL-18 secretion by dendritic cells (DCs) . To determine the influence of bacterial virulence factors on the activation and release of IL-18, we infected human monocyte-derived DCs with virulence mutants of the facultative intracellular pathogen Salmonella typhimurium . Our results show that infection by S . typhimurium causes caspase-1-dependent activation of IL-18 and triggers the release of IL-18 in human DCs . The secretion of IL-18 by the DCs was closely correlated with the ability of the S . typhimurium strains to induce apoptosis . We demonstrate that activation and release of IL-18 are blocked by mutations in the Salmonella sipB gene, which encodes a virulence factor that activates caspase-1 to induce apoptosis . These findings indicate that the activation and release of IL-18 induced by bacterial virulence factors may represent one component of innate immunity against the intracellular bacteria. J Rheumatol, 2002 Oct, 29(10), 2154 - 8 Reactive arthritis and other sequelae following sporadic Salmonella typhimurium infection in British Columbia, Canada: a case control study; Buxton JA et al.; OBJECTIVE: To describe sequelae occurring in the 3 months after sporadic Salmonella typhimurium (ST) infection in British Columbia (BC), Canada . METHODS: We compared the incidence of sequelae to similar symptoms in controls; identified risk factors for developing sequelae; identified the incidence of reactive arthritis (ReA) as diagnosed by a rheumatologist, and assessed primary care physician diagnosis of ReA . A questionnaire was administered by telephone to cases of ST occurring in BC between December 1, 1999, and November 30, 2000; and to controls obtained from the BC provincial client registry . Cases reporting symptoms were followed up by a rheumatologist . RESULTS: Thirty-five of 66 (53%) cases reported any symptom, 17 (26%) reported joint symptoms . The Mantel-Haenszel odds ratio (weighted by sex and pediatric/adult) of a salmonella case reporting "any symptom" compared to controls was 5.42; 95% confidence interval (CI) 2.18-16.27; and reporting joint symptoms was 4.40; 95% CI: 1.25-19.53 . The sex distribution of cases reporting joint symptoms was not significantly different . No medication taken during the salmonella infection was significantly different between the cases who had joint symptoms and those who did not . Four cases (2 adults, 2 children) were considered by the rheumatologist to have symptoms consistent with ReA, 2 of these had been told by a physician that their symptoms were related to their ST infection . CONCLUSION: Cases were more than 4 times more likely to report joint symptoms than controls; and despite the loss of many cases to followup, 6% of all cases were considered to have ReA. J Environ Qual, 2002 Sep-Oct, 31(5), 1702 - 9 Salmonella typhimurium survival and viability is unaltered by suspended particles in freshwater; Maki RP et al.; Rolling microcosm experiments were conducted to determine whether suspended particles affect the survival and viability of a model pathogen, Salmonella choleraesuis, serotype typhimurium (American Type Culture Collection no . 23567), in a freshwater microbial community . Water from the Duluth, MN harbor of Lake Superior (including native microorganisms) was inoculated with clay, silt, or flocculent organic particles in a range of concentrations and a streptomycin-resistant strain of S . typhimurium . Microcosms (incubated at 20 degrees C) were rolled horizontally (3 rpm) and sampled periodically for total bacteria and total, viable, and culturable S . typhimurium . Total S . typhimurium abundance decreased rapidly in all experiments (8.5-73.1% d-1) . Total bacteria did not decrease as rapidly as the S . typhimurium population in any experiment, suggesting that a microcosm effect was not responsible for the decline in S . typhimurium populations . Loss rates of attached and free cells were similar, indicating that attachment to particles did not enhance the persistence of Salmonella cells beyond our minimum detectable differences . After eight days, only 0.1 to 11.9% of the initial S . typhimurium inocula were detected by direct counts . Suspended particles had a minimal effect on the survival and viability of S . typhimurium; the losses of total, viable, or culturable Salmonella were generally the same across particle treatments and concentrations . Silt and flocculent particles affected loss rates of total and viable S . typhimurium similarly to inorganic particles (clay) . It appears unlikely that suspended particles would provide a means for S . typhimurium to persist at hazardous levels in freshwater. J Immunol, 2002 Oct 15, 169(8), 4475 - 80 Neutrophil influx in response to a peritoneal infection with Salmonella is delayed in lipopolysaccharide-binding protein or CD14-deficient mice; Yang KK et al.; The induction of an adaptive immune response to a previously unencountered pathogen is a time-consuming process and initially the infection must be held in check by the innate immune system . In the case of an i.p . infection with Salmonella typhimurium, survival requires both CD14 and LPS-binding protein (LBP) which, together with Toll-like receptor 4 and myeloid differentiation protein 2, provide a sensitive means to detect bacterial LPS . In this study, we show that in the first hours after i.p . infection with Salmonella a local inflammatory response is evident and that concomitantly neutrophils flood into the peritoneum . This rapid neutrophil influx is dependent on TNF since it is 1) abolished in TNF KO mice and 2) can be induced by i.p . injection of TNF in uninfected animals . Neutrophil influx is not strictly dependent on the presence of either LBP or CD14 . However, in their absence, no local inflammatory response is evident, neutrophil migration is delayed, and the mice succumb to the infection . Using confocal microscopy, we show that the neutrophils which accumulate in CD14 and LBP null mice, albeit with delayed kinetics, are nevertheless fully capable of ingesting the bacteria . We suggest that the short delay in neutrophil influx gives the pathogen a decisive advantage in this infection model. J Immunol, 2002 Oct 15, 169(8), 4262 - 72 Pentoxifylline functions as an adjuvant in vivo to enhance T cell immune responses by inhibiting activation-induced death; Suresh R et al.; Modalities for inducing long-lasting immune responses are essential components of vaccine design . Most currently available immunological adjuvants empirically used for this purpose cause some inflammation, limiting clinical acceptability . We show that pentoxifylline (PF), a phosphodiesterase (PDE) inhibitor in common clinical use, enhances long-term persistence of T cell responses, including protective responses to a bacterial immunogen, Salmonella typhimurium, via a cAMP-dependent protein kinase A-mediated effect on T cells if given to mice for a brief period during immunization . PF inhibits activation-mediated loss of superantigen-reactive CD4 as well as CD8 T cells in vivo without significantly affecting their activation, and inhibits activation-induced death and caspase induction in stimulated CD4 as well as CD8 T cells in vitro without preventing the induction of activation markers . Consistent with this ability to prevent activation-induced death in not only CD4 but also CD8 T cells, PF also enhances the persistence of CD8 T cell responses in vivo . Thus, specific inhibition of activation-induced T cell apoptosis transiently during immune priming is likely to enhance the persistence of CD4 and CD8 T cell responses to vaccination, and pharmacological modulators of the cAMP pathway already in clinical use can be used for this purpose as immunological adjuvants. Br Poult Sci, 2002 Sep, 43(4), 501 - 7 Genetic resistance to Salmonella typhimurium in two lines of chickens selected as resistant and sensitive on the basis of heterophil/lymphocyte ratio; Al-Murrani WK et al.; 1 . A study was conducted to test for the validity of the heterophil/lymphocyte (H/L) ratio as a criterion for selection for resistance to Salmonella typhimurium in chickens . 2 . An infective dose of S . typhimurium was given, directly in the crop, to two groups of chicken selected as Resistant (R) and Sensitive (S) on the bases of H/L ratio . The 99% lower confidence limit was used as a borderline; individuals below the limit were considered R and those above S . Many aspects of immune response were compared, namely: H/L ratio, antibody titre, cellular immunity, phagocytic activity, cortisol concentration, bursa and body weight . 3 . The R group exceeded the S in all the studied variables of the immune response, indicating the possibility of using the H/L ratio and its confidence limit to select for general resistance . 4 . Due to the within-strain variability in resistance, it seems that immunological and genetic studies should take into consideration separation of individuals into R and S before grouping . Failing to do so might lead to erroneous conclusions as a difference may simply be due to the different numbers of R and S included in each group. Nat Cell Biol, 2002 Oct, 4(10), 766 - 73 Elimination of host cell PtdIns(4,5)P(2) by bacterial SigD promotes membrane fission during invasion by Salmonella; Terebiznik MR et al.; Salmonella invades mammalian cells by inducing membrane ruffling and macropinocytosis through actin remodelling . Because phosphoinositides are central to actin assembly, we have studied the dynamics of phosphatidylinositol-4,5-bisphosphate (PtdIns(4,5)P(2)) in HeLa cells during invasion by Salmonella typhimurium . Here we show that the outermost parts of the ruffles induced by invasion show a modest enrichment in PtdIns(4,5)P(2), but that PtdIns(4,5)P(2) is virtually absent from the invaginating regions . Rapid disappearance of PtdIns(4,5)P(2) requires the expression of the Salmonella phosphatase SigD (also known as SopB) . Deletion of SigD markedly delays fission of the invaginating membranes, indicating that elimination of PtdIns(4,5)P(2) may be required for rapid formation of Salmonella-containing vacuoles . Heterologous expression of SigD is sufficient to promote the disappearance of PtdIns(4,5)P(2), to reduce the rigidity of the membrane skeleton, and to induce plasmalemmal invagination and fission . Hydrolysis of PtdIns(4,5)P(2) may be a common and essential feature of membrane fission during several internalization processes including invasion, phagocytosis and possibly endocytosis. J Med Microbiol, 2002 Sep, 51(9), 771 - 6 Increased in-vitro and in-vivo biological activity of lipopolysaccharide extracted from clinical low virulence vacA genotype Helicobacter pylori strains; Salgado F et al.; Helicobacter pylori infection in man is associated with chronic gastritis and peptic ulcer disease . The virulence factors of the species are still under investigation . Among these, the lipopolysaccharide (LPS) is a potential pathogenic factor of the micro-organism, whose biological activity can be estimated by immunological parameters . The aim of this study was to determine the ability of pure LPS extracted from clinical isolates of H . pylori to induce mitogenicity, secretion of tumour necrosis factor-alpha (TNF-alpha), and spleen growth in a murine model . Rough and smooth LPS from Salmonella typhimurium were used as controls . The results showed that, like the control LPS, all extracts of LPS induced mitogenic activity, stimulated synthesis of TNF-alpha and induced spleen growth, although the effects produced by the majority of the H . pylori LPS samples analysed were less intensive than those produced by the S . typhimurium LPS . The immunological parameters analysed allowed the detection of two types of H . pylori LPS: one of low biological activity and one of high biological activity . The most active LPS was extracted from strains isolated from patients with increased mucous damage associated with epithelial regeneration . Surprisingly, these strains were cagA negative and belonged to a low virulence genotype according to vacA gene (slbm2 and s2m2) . The results suggest the need to re-evaluate the role of the LPSas a virulence factor for some strains of H . pylori. Eur J Immunol, 2002 Oct, 32(10), 2800 - 6 Toll-like receptor 4 is not required for the full maturation of dendritic cells or for the degradation of Gram-negative bacteria; Rescigno M et al.; Toll-like receptor 4 (TLR4) has been recently associated with cellular responses to lipopolysaccharide (LPS), and mice mutated in tlr4, such as C57BL/10ScCr or C3H/HeJ mice, become hyporesponsive to LPS . In this study, we have analyzed the capacity of bone marrow-derived dendritic cells (BMDC) from C57BL/10ScCr (ScCr-BMDC) or C3H/HeJ (HeJ-BMDC) mice to respond to LPS or to Gram-negative bacteria . We show that ScCr- or HeJ-BMDC are insensitive to LPS, but can mature in response to live and killed Gram-negative bacteria . Interestingly, only ScCr-BMDC but not HeJ-BMDC, stimulated with bacteria, have reduced capacity to produce pro- and anti-inflammatory cytokines as compared to BMDC from control mice, probably due to genetic defects unrelated to the tlr4 mutation . Nevertheless, ScCr-BMDC and ScCr BM-macrophages (BM-Mphi) phagocytose Salmonella typhimurium similarly to control cells, indicating that TLR4 is not compulsory for bacterial uptake . Moreover, BM-Mphi, but not BM-DC from B10ScCr or C3H/HeJ mice, are impaired in their capacity to kill intracellular bacteria and to produce NO as compared to wild type controls . However, the bacteria killing property of BM-Mphi is completely restored by pretreating the cells with IFN-gamma . Hence, TLR4 plays different roles in DC versus Mphi. J Infect Dis, 2002 Oct 15, 186(8), 1122 - 30 Epub 2002 Sep 20. Inhibition of Salmonella typhimurium enteropathogenicity by piperidine, a metabolite of the polyamine cadaverine; Kohler H et al.; Piperidine is a 1-ring heterocyclic compound formed from the polyamine cadaverine in the human intestine . Because heterocyclic compounds are routinely used in the promotion of antimicrobial treatment strategies, it was considered whether piperidine could be used against infection with enteric pathogens . This study demonstrates that piperidine treatment prevented the invasion of Salmonella typhimurium into model intestinal epithelium by nearly 95% . In vivo studies also revealed that it increased mouse survival and reduced S . typhimurium translocation into and colonization of various organs and tissues . Initial evaluations demonstrated that piperidine reduced the S . typhimurium-induced polymorphonuclear leukocyte transepithelial migration response in vitro by inhibiting activation of protein kinase C . Piperidine did not affect the ability of S . typhimurium to elicit interleukin-8 secretion by epithelial cells or to activate extracellular-regulated kinase signal transduction pathways . These results show that piperidine does not exhibit paninhibitory activity and suggest that piperidine may be useful in down-regulating active inflammation at mucosal surfaces. Mutat Res, 2002 Sep 30, 506-507, 41 - 8 The effect of deuterium and fluorine substitution upon the mutagenicity of N-hydroxy-2,6-dimethylaniline; Matilde Marques M et al.; 2,6-Dimethylaniline (2,6-DMA) is an intermediate in the manufacture of several products, including pesticides, dyestuffs, and synthetic resins . It is also present in nanogram amounts in tobacco smoke, and is a major metabolite of the potent anesthetic and antiarrhythmic drug lidocaine, as well as a nasal carcinogen in rats . As with other aromatic amines, 2,6-DMA can undergo metabolic activation through cytochrome p450-mediated N-hydroxylation, followed by O-esterification to a reactive derivative capable of forming DNA adducts . We have recently characterized four DNA adducts resulting from this metabolic pathway . Three of the adducts arose from reaction of the exocyclic heteroatoms of deoxyadenosine and deoxyguanosine with the carbon para to the arylamine nitrogen . The fourth adduct resulted from reaction of the 2,6-DMA nitrogen with the C8 atom of deoxyguanosine . In order to investigate the relative contribution of the exocyclic heteroatom adducts as compared to the C8-deoxyguanosine adduct to the toxicities elicited by 2,6-DMA, we synthesized and compared the mutagenicity of N-hydroxy-2,6-DMA, N-hydroxy-4-deutero-2,6-DMA, 2,6-dimethylnitrosobenzene, 4-deutero-2,6-dimethylnitrosobenzene, and N-hydroxy-4-fluoro-2,6-DMA . In Salmonella typhimurium TA100, the two deuterated compounds and their non-deuterated analogues gave similar mutagenic responses ( approximately 25 revertants/nmol) . Likewise in S . typhimurium TA98, a similar mutant frequency ( approximately 0.7 revertants/nmol) was obtained with the four compounds . With N-hydroxy-4-fluoro-2,6-DMA, the mutant frequency was reduced by approximately 90% in S . typhimurium TA100 and approximately 50% in S . typhimurium TA98 . The results suggest that multiple adducts contribute to base substitution mutations detected by S . typhimurium TA100 while the C8-deoxyguanosine adduct is primarily responsible for the frameshift mutations detected by S . typhimurium TA98. Cent Eur J Public Health, 2002 Sep, 10(3), 104 - 6 Antibacterial efficacy of disinfectants against some gramnegative bacteria; Majtan V et al.; The antibacterial effect of 11 new commercially manufactured disinfectants on clinical isolates of Salmonella typhimurium DT104, Serratia marcescens and Pseudomonas aeruginosa was studied . The substances tested represented six pure quaternary ammonium substances (QAS) and five QAS combined with other ingredients . The antibacterial efficacy was characterized by influencing the growth of bacterial cells expressed by MIC and ED50 values . The disinfectants are divided into three groups according to their efficacy . The antibacterial efficacy of disinfectants on S . typhimurium DT104 in the study is the highest in comparison with S . marcescens and P . aeruginosa strains . The highest inhibition of growth was caused by Diesen forte on S . typhimurium DT 104 and by Benzalkonium chloride on both S . marcescens and P . aeruginosa strains. Mutat Res, 2002 Sep 26, 520(1-2), 119 - 24 Mutagenic activity of the glutathione S-transferase substrate 1-chloro-2,4-dinitrobenzene (CDNB) in the Salmonella mutagenicity assay; Catterall F et al.; The mutagenicity of the commonly used glutathione S-transferase substrates 1-chloro-2,4-dinitrobenzene (CDNB) and 1,2-dichloro-4-nitrobenzene (DCNB) was investigated in the Salmonella mutagenicity assay . CDNB induced a concentration-dependent mutagenic response in Salmonella typhimurium strain TA98 . Incorporation of an activation system derived from Aroclor 1254-induced rats did not influence mutagenic response . Under the same conditions DCNB failed to display mutagenic activity . The mutagenic activity of CDNB was attenuated in bacterial strains under-expressing nitroreductase or O-acetylase activity but, in contrast, it was exaggerated in an O-acetylase over-expressing strain . It is inferred that CDNB exhibits a mutagenic response following reduction of the nitro-group to the hydroxylamine, which is further acetylated to form the acetoxy derivative that presumably breaks down spontaneously to generate the nitrenium ion, the likely ultimate mutagen. Proc Natl Acad Sci U S A, 2002 Oct 15, 99(21), 13681 - 6 Epub 2002 Sep 23. Macrophage migration inhibitory factor (MIF) plays a pivotal role in immunity against Salmonella typhimurium; Koebernick H et al.; The cytokine macrophage migration inhibitory factor (MIF) exerts a multitude of biological functions . Notably, it induces inflammation at the interface between the immune system and the hypothalamus-pituitary-adrenal stress axis . The role of MIF in infectious diseases is not understood completely . Here, we show that MIF-deficient (MIF(-/-)) knockout mice fail to control an infection with wild-type Salmonella typhimurium . Increased susceptibility was accompanied by a reduced Th1 response, demonstrated by decreased levels of IL-12, IFNgamma, and tumor necrosis factor alpha . In Salmonella-infected MIF(-/-) mice, levels of IL-1beta were markedly increased . Additionally, infected MIF(-/-) mice showed elevated serum levels of nitric oxide and corticosterone as compared with control mice . Our results point to MIF as a key mediator in the host response to S . typhimurium . MIF not only promotes development of a protective Th1 response but ameliorates disease by altering levels of reactive nitrogen intermediates and corticosteroid hormones, which both exert immunosuppressive functions. J Immunol, 2002 Oct 1, 169(7), 3900 - 7 Divergent role for TNF-alpha in IFN-gamma-induced killing of Toxoplasma gondii and Salmonella typhimurium contributes to selective susceptibility of patients with partial IFN-gamma receptor 1 deficiency; Janssen R et al.; Patients with defects in IFN-gamma- or IL-12-mediated immunity are susceptible to infections with Salmonella and non-tuberculous mycobacteria, but rarely suffer from infections with other intracellular pathogens such as Toxoplasma gondii . Here we describe macrophage and T cell function in eight individuals with partial IFN-gamma receptor 1 (IFN-gammaR1) deficiency due to a mutation that results in elevated cell surface expression of a truncated IFN-gammaR1 receptor that lacks the intracellular domain . We show that various effector mechanisms dependent on IFN-gammaR signaling are affected to different extents . Whereas TNF-alpha production was normally up-regulated in response to IFN-gamma, IL-12 production and CD64 up-regulation were strongly reduced, and IFN-gamma-mediated killing of the intracellular pathogens Salmonella typhimurium and T . gondii was completely abrogated in patient's macrophages . Since these patients suffer selectively from infections with non-tuberculous mycobacteria and Salmonella, but not T . gondii, despite sero-immunity in six of eight patients, which indicates previous contact with this pathogen, we next studied the role of TNF-alpha as a possible immune compensatory mechanism . IFN-gamma-induced killing of T . gondii appeared to be partially mediated by TNF-alpha, and addition of TNF-alpha could compensate for the abrogated killing of T . gondii in the patient's macrophages . In contrast, IFN-gamma-mediated killing of S . typhimurium appeared to be independent of TNF-alpha . We propose that the divergent role of TNF-alpha in IFN-gamma-induced killing of T . gondii and S . typhimurium may at least partially explain the highly selective susceptibility of patients. Vet Microbiol, 2002 Oct 22, 89(2-3), 167 - 79 A laboratory study of an inactivated bivalent iron restricted Salmonella enterica serovars Enteritidis and Typhimurium dual vaccine against Typhimurium challenge in chickens; Clifton-Hadley FA et al.; A commercial inactivated iron restricted Salmonella Typhimurium and Salmonella Enteritidis vaccine was used to vaccinate chicks at 1 day and again at 4 weeks of age, with challenge by a high and a low dose of S . Typhimurium given either orally or by contact with seeder birds inoculated orally with a high dose of S . Typhimurium . In all three challenge regimes, the shedding of challenge strain was reduced significantly (p < 0.05) in vaccinated birds compared with unvaccinated controls . Vaccination reduced colonisation of internal organs after challenge by contact seeder birds . However, no effect of vaccination upon colonisation of internal organs after either high or low oral challenge was apparent . In conclusion, the data indicate that the vaccine should be a useful tool in the control of S . Typhimurium infection in chickens. Mol Gen Mikrobiol Virusol, 2002, (3), 34 - 40 {NRAMP1 gene: structure, function, and human infectious diseases}; Puzyrev VP et al.; The human infectious disease become of the great importance for Health Welfare . The infectious diseases mortality rate reaches one third of total mortality among 51 million patients died annually . The genetic factors seem to be most responsible for potency of human body to withstand to infections, caused by a variety of causative agents . The detection of the coincident factors and understanding the mechanisms of formation of susceptibility and resistance to infectious agents appeared to be important aspects for development of the new methods of prevention and treatment the infectious diseases . In inbred mice the natural resistance to infections, caused by Mycobacterium bovis, Mycobacterium avium, Mycobacterium lepraemurium, Leishmania donovani and Salmonella typhimurium is controlled by gene Nrampl (natural resistance associated macrophage protein gene) . The gene codes for integral membrane protein, expressed by phagocytes . Protein is localized in the endosomal/lysosomal compartment of the silent macrophage, being recruited to the membrane of the phagosome containing particles under phagocytosis . This function is to transfer bivalent cations of metals from phagosome inward macrophage, that appears to affect negatively on destiny of microbes consumed . The human homologue of the Nrampl gene, denoted as NRAMP1, is situated on human chromosome 2q35 . The gene Nrampl consists of 15 exones of different spread disparted by intrones of various sizes . Several polymorphous variants of the gene are described . The experimental presuppositions to more extensive investigation of the role of the gene NRAMPl in development of human pathology are pointed out. J Biol Chem, 2002 Nov 22, 277(47), 45068 - 74 Epub 2002 Sep 17. Comparative mutagenesis of the C8-guanine adducts of 1-nitropyrene and 1,6- and 1,8-dinitropyrene in a CpG repeat sequence . A slipped frameshift intermediate model for dinucleotide deletion; Hilario P et al.; In the Ames Salmonella typhimurium reversion assay 1,6- and 1,8-dinitropyrenes (1,6- and 1,8-DNPs) are much more potent mutagens than 1-nitropyrene (1-NP) . Genetic experiments established that certain differences in the metabolism of the DNPs, which in turn result in increased DNA adduction, play a role . It remained unclear, however, if the DNP adducts, N-(guanin-8-yl)-1-amino-6 ()-nitropyrene (Gua-C8-1,6-ANP and Gua-C8-1,8-ANP), which contain a nitro group on the pyrene ring covalently linked to the guanine C8, are more mutagenic than the major 1-NP adduct, N-(guanin-8-yl)-1-aminopyrene (Gua-C8-AP) . In order to address this, we have compared the mutation frequency of the three guanine C8 adducts, Gua-C8-AP, Gua-C8-1,6-ANP, and Gua-C8-1,8-ANP in a CGCG*CG sequence . Single-stranded M13mp7L2 vectors containing these adducts and a control were constructed and replicated in Escherichia coli . A remarkable difference in the induced CpG deletion frequency between these adducts was noted . In repair-competent cells the 1-NP adduct induced 1.7% CpG deletions without SOS, whereas the 1,6- and 1,8-DNP adducts induced 6.8 and 10.0% two-base deletions, respectively . With SOS, CpG deletions increased up to 1.9, 11.1, and 15.1% by 1-NP, 1,6-, and 1,8-DNP adducts, respectively . This result unequivocally established that DNP adducts are more mutagenic than the 1-NP adduct in the repetitive CpG sequence . In each case the mutation frequency was significantly increased in a mutS strain, which is impaired in methyl-directed mismatch repair, and a dnaQ strain, which carries a defect in proofreading activity of the DNA polymerase III . Modeling studies showed that the nitro group on the pyrene ring at the 8-position can provide additional stabilization to the two-nucleotide extrahelical loop in the promutagenic slipped frameshift intermediate through its added hydrogen-bonding capability . This could account for the increase in CpG deletions in the M13 vector with the nitro-containing adducts compared with the Gua-C8-AP adduct itself. J Food Prot, 2002 Sep, 65(9), 1475 - 9 Salmonella spp . on chicken carcasses in processing plants in Poland; Mikolajczyk A et al.; Chickens at selected points in the slaughter process and after slaughter on the dressing line in poultry plants were sampled and analyzed for Salmonella . These chickens came from the northeast part of Poland . The examinations were carried out in quarters I, II, III, and IV of 1999 . All the birds were determined to be healthy by a veterinary inspection . Swab samples were taken from the cloaca after stunning and from the skin surface and body cavity of the whole bird after evisceration, after rinsing at the final rinse station but before chilling in the spin-chiller, and after cooling in the continuous cooling plant at the end of the production day . In 1999, 400 whole chickens were examined . The percentage of these 400 chickens from which Salmonella spp . were isolated was relatively high (23.75%; Salmonella-positive results were observed in 95 cases) . Salmonella spp . were found after stunning in 6% of the chickens (6 of 100 samples), after evisceration in 24% (24 of 100), before cooling in 52% (52 of 100), and after cooling in 13% (13 of 100) . These results show that Salmonella spp . were found more often at some processing points than at others . The lowest Salmonella spp . contamination rate (6%) for slaughter birds was found after stunning, and the highest contamination rate was found before chilling (52%) . The serological types of Salmonella spp . isolated from whole chickens were Salmonella Enteritidis, Salmonella Typhimurium, Salmonella Saintpaul, Salmonella Agona, and Salmonella Infantis . The results of these investigations indicate that Salmonella Enteritidis is the dominant serological type in infections of slaughter chickens, as it is in many countries. J Food Prot, 2002 Sep, 65(9), 1463 - 9 Evaluation of antioxidative and mutagenic properties of 50% ethanolic extract from red beans fermented by Aspergillus oryzae; Chou ST et al.; Various bean products fermented by microorganisms are commonly consumed in Asian diets; however, the safety or functional properties of fermented beans can vary with different microbial species and with different processes being applied to different beans . The objectives of this study were to evaluate the antioxidative and mutagenic properties of 50% ethanolic extracts from red beans fermented by Aspergillus oryzae . The extracts' antioxidative activities, including alpha,alpha;-diphenyl-beta-picryl-hydrazyl (DPPH) radical-scavenging effects, Fe(2+)-chelating ability, and reducing power, were studied in vitro . The antioxidative effects provided by the extracts depended strongly on their concentrations . In general, antioxidative activity increased with extract concentration to a certain point and then leveled off as the concentration further increased . The fermented red bean extracts showed less of a scavenging effect on the DPPH radical and less reducing power than the commercial antioxidants alpha-tocopherol and butylated hydroxytoluene, but better Fe(2+)-chelating ability . No mutagenicity or toxicity effect on any of the tested strains (Salmonella Typhimurium TA97, TA98, TA100, TA102, and TA1535) was found for the 50% ethanolic extracts of fermented red beans with the Ames mutagenicity assay . These results suggest that the 50% ethanolic extracts were not mutagenic. Plant Physiol, 1993 Mar, 101(3), 1073 - 1080 Pyrophosphorylases in Solanum tuberosum (IV . Purification, Tissue Localization, and Physicochemical Properties of UDP-Glucose Pyrophosphorylase); Sowokinos JR et al.; The enzyme UDP-glucose pyrophosphorylase (UGPase) from potato (Solanum tuberosum L . cv Norchip) tubers was purified 177-fold to near homogeneity and to a specific activity of 1099 international units/mg of protein . The molecular mass of the purified enzyme was 53 kD as determined by SDS-PAGE and gel filtration . Immunological and activity assays detected UGPase at similar levels in potato stems, stolons, and tubers . Leaves and roots contained lower levels of UGPase activity and protein . Lineweaver-Burk plots for substrates inorganic pyrophosphate and UDP-glucose were linear in the pyrophosphorolytic direction, yielding Km values of 0.13 and 0.14 mM, respectively . However, Lineweaver-Burk plots for the substrates glucose-1-P and UTP were biphasic in nature when UGPase was assayed in the direction of UDP-glucose synthesis . At physiological substrate concentrations (i.e . from 0.05-0.20 mM), Km values of 0.08 mM (glucose-1-P) and 0.12mM (UTP) were obtained . When substrate concentrations increased above 0.20 mM, Km values increased to 0.68 mM (glucose-1-P) and 0.53 mM (UTP) . These kinetic patterns of potato UGPase suggest a "negative cooperative effect" (A . Conway, D.E . Koshland, Jr . {1968} Biochemistry 7: 4011-4022) with respect to the substrates glucose-1-P and UTP . The biphasic substrate saturation curves were similar to the kinetics of the dimeric form of UGPase purified from Salmonella typhimurium (T . Nakae {1971} J Biol Chem 246: 4404-4411) . The in vivo significance of the enzyme's "negative cooperativity" in the direction of UDP-glucose synthesis and potato sweetening is discussed. J Endotoxin Res, 2002, 8(4), 263 - 71 Lipopolysaccharide binds to and activates A(1) adenosine receptors on human pulmonary artery endothelial cells; Wilson CN et al.; Previously, it was reported that A(1) adenosine receptor antagonists prevent endotoxin-induced acute lung injury and pulmonary arterial endothelial cell damage . In competition radioligand binding experiments in membranes prepared from human pulmonary artery endothelial cells (PAECs), lipopolysaccharides (LPSs) of Escherichia coli, Salmonella typhimurium, Klebsiella pneumoniae, and Pseudomonas aeruginosa displaced the binding of a selective A(1) adenosine receptor antagonist {(125)I}-BWA844U (IC(50) values: 195 ng/ml, 290 ng/ml, 602 ng/ml, and 693 ng/ml, respectively) in a dose-dependent, competitive manner . There was no displacement of this radioligand by enterotoxin (< or = 10 microg/ml), diphosphoryl lipid A (< or = 10 microg/ml), and glycolipids, monosialoganglioside (< or = 1 microg/ml), lactocerebroside (< or = 100 microg/ml), or NBD galactocerebroside (< or = 100 microg/ml) . Based on calculated IC(50) values, LPS (E . coli, IC(50) 111 ng/ml) displaced the selective A(1) adenosine receptor agonist, {(3)H}-2-chloro, N(6)-cyclopentyladenosine (CCPA) in human PAECs with a potency profile, CCPA > LPS > 2-phenylaminoadenosine (CV 1808), a selective A(2) adenosine receptor agonist . The potency profile for displacement of the selective A(2a) adenosine receptor agonist {(3)H}-CGS 21680 was CV 1808 > CCPA . LPS (E . coli 0.1 pg/ml-10 microg/ml) did not displace {(3)H}-CGS 21680 binding . In human PAECs, IL-6 and TXA(2) release induced by LPS (0-1 microg/ml) or CCPA (0-1 microM) at high doses was significantly reduced by the selective A(1) adenosine receptor antagonist, 8-cyclopentyl-1,3-dipropylxanthine (DPCPX; 1 microM) . These data suggest that LPS binds to and activates A(1) adenosine receptors on human PAECs to induce the release of IL-6 and TXA(2) . Activation of A(1) adenosine receptors on human PAECs by LPS, may contribute to the pathophysiology of acute lung injury associated with Gram-negative septicemia and endotoxemia. Int J Food Microbiol, 2002 Oct 25, 78(3), 227 - 34 PCR amplification of the Salmonella typhimurium fimY gene sequence to detect the Salmonella species; Yeh KS et al.; This study evaluated the suitability of fimY gene amplification by PCR as an effective means of detecting Salmonella species . Although fimY gene of Salmonella typhimurium is involved in regulating type 1 fimbrial expression, the amino acid sequence of FimY shares very little homology with other known prokaryotic proteins in the GenBank database . Therefore, fimY is a promising target gene to detect the presence of Salmonella species . Herein, two primers internal to the fimY gene of S . typhimurium are used to investigate the distribution of the fimY homologous sequence among 45 Salmonella serovars and 20 non-Salmonella species by using PCR . Experimental results indicated that only Salmonella species possessed the fimY homologous sequence, subsequently generating the specific 526-bp DNA fragments . The sensitivity of the fmY-specific primer set was demonstrated on a Salmonella-free swab sample from a pork carcass surface, which was then artificially contaminated with different concentrations of S . typhimurium . A combining of pre-enrichment step in buffered peptone water and PCR amplification of fimY allowed the detection of S . typhimurium at the concentration of 3.4 x 10(0) CFU/ml from the swab sample . With an additional enrichment step in Rappaport-Vassiliadis (RV) broth, this procedure can also detect pork carcass surface naturally contaminated with Salmonella species in a slaughterhouse . Results in this study demonstrate that fimY is unique to Salmonella species and is an appropriate PCR target for detecting these microorganisms. Biosci Biotechnol Biochem, 2002 Jul, 66(7), 1450 - 4 2-{3-(2-Thioxopyrrolidin-3-ylidene)methyll-tryptophan, a novel yellow pigment in salted radish roots; Matsuoka H et al.; The structure of the yellow pigment found in salted radish roots was studied . It was found that 1-(2-thioxopyrrolidin-3-yl)-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid (TPCC) was unstable under neutral pH, and was easily converted into the yellow pigment . The yellow pigment was isolated and identified as 2-{3-(2-thioxopyrrolidin-3-ylidene)methyl}-tryptophan (TPMT) by IR, MS, 1H-, and 13C-NMR spectroscopy . In addition, we proved that this compound was the main yellow pigment in salted radish roots . This compound induced no mutagenicity in Salmonella typhimurium TA98 and TA100, either with or without prior activation. Biol Chem, 2002 Jun, 383(6), 977 - 82 N-hydroxyarylamine O-acetyltransferase-deficient Escherichia coli strains are resistant to the mutagenicity of nitro compounds; Josephy PD et al.; In Salmonella typhimurium, a single enzyme catalyzes both the acetyl CoA-dependent O-acetylation of hydroxylamines (a key step in the activation of mutagenic nitroaromatic compounds and related aromatic and heterocyclic amines) and the N-acetylation of aromatic amines . S . typhimurium Ames test mutants lacking this activity are highly resistant to the genotoxic effects of nitro compounds . However, such mutants have not yet been obtained in Escherichia coli . We used a PCR-based method to engineer a null mutation (deletion) of the nhoA gene encoding the enzyme in E . coli and we transduced this mutation into a lacZ strain background suitable for use in mutation assays . In E . coli, as in S . typhimurium, nhoA mutants show marked resistance to nitro compound mutagenicity . The new strains provide a clean background for expression of recombinant N-acetyltransferases. East Afr Med J, 2001 Nov, 78(11), 576 - 80 Salmonella, Shigella and growth potential of other food-borne pathogens in Ethiopian street vended foods; Muleta D et al.; OBJECTIVE: To evaluate the bacteriological safety of food items sold by street vendors with regard to Salmonella and Shigella and to assess the growth potential of some foodborne pathogens in some street foods . DESIGN: Collection of street-vended foods and laboratory based microbiological analysis . Setting: Microbiology Laboratory, Department of Biology, Addis Ababa University, Addis Ababa, Ethiopia . RESULTS: Most of the street food samples had aerobic mesophilic counts >10(7) cfu/g . Nine "kitfo" and one "egg sandwich" samples yielded Salmonella . Shigella was isolated from three "macaroni" samples . The Salmonella isolates were sensitive to all ten drugs tested but the Shigella isolates had multiple resistance against five drugs . In a challenge study, Salmonella typhimurium, Shigella flexneri and Staphylococcus aureus grew in street-vended food samples to hazardous levels within eight to twelve hours . CONCLUSION: Street foods are heavily contaminated with micro-organisms and are potential sources of food borne infections . Health hazards from street foods may be significantly minimised by consumption within four hours of preparation. Eur J Immunol, 2002 Sep, 32(9), 2664 - 71 Processing of viable Salmonella typhimurium for presentation of a CD4 T cell epitope from the Salmonella invasion protein C (SipC); Musson JA et al.; We have identified Salmonella invasion protein C (SipC) as a target antigen for CD4 T cell recognition in mice infected with Salmonella typhimurium . SipC is a product of the type III secretion system encoded by S . typhimurium pathogenicity island 1 . A SipC-specific T cell response was induced by infection with either the C5 wild type or attenuated SL3261 vaccine strain of S . typhimurium . We localized the response of T cell lines from infected mice to an epitope near the carboxyl terminus of SipC (SipC(381-394)) and studied the way it was processed from viable S . typhimurium . We demonstrated that CD4 T cell recognition of this epitope required actin-dependent uptake of S . typhimurium . Presentation also occurred when transport of newly synthesized MHC class II from the endoplasmic reticulum was disrupted and when the pH of intracellular compartments was raised, suggesting presentation by mature MHC class II recycled from the macrophage surface into neutral intracellular compartments . Salmonellae are known to colonize macrophages by localizing to compartments that do not make contact with the bactericidal environment of late endosomes or lysosomes, and thus might avoid lysosomal antigen processing . However, we demonstrate that a CD4 T cell response to S . typhimurium-secreted proteins may be induced by an alternative pathway capable of antigen presentation in conditions similar to those in the compartments where Salmonella localize. J Immunol, 2002 Sep 15, 169(6), 3275 - 83 Induction of CD8+ T lymphocytes by Salmonella typhimurium is independent of Salmonella pathogenicity island 1-mediated host cell death; Wijburg OL et al.; Salmonella are intracellular bacterial pathogens that reside and replicate inside macrophages, and attenuated strains of Salmonella typhimurium can be used to deliver heterologous Ags for MHC class I and/or MHC class II-restricted presentation . Recently, it was shown that invasion of macrophages by S . typhimurium may result in the death of host macrophages via a mechanism harboring features of apoptotic and necrotic cell death . However, it is unknown whether this bacterial-induced host cell death affects immunity . In addition, it has been hypothesized that macrophage death following infection with S . typhimurium and subsequent uptake of apoptotic cells by APC are fundamental to the induction of CTL responses . In this study we investigated the in vivo induction of Ag-specific CD8+ T lymphocyte responses and compared CD8+ T lymphocyte responses elicited with S . typhimurium strains carrying a mutation in their invA gene, and therefore an inability to induce Salmonella pathogenicity island 1 (SPI-1)-mediated macrophage death, with responses elicited by an attenuated deltaaroAD strain . Ag-specific CD8+ T lymphocyte responses were analyzed using IFN-gamma ELISPOT, tetramer binding, and in vivo and in vitro CTL assays . Our results showed that deltaaroAD and deltaaroADdeltainvA induced comparable levels of Ag-specific CD8+ T lymphocyte responses as well as protective, Ag-specific B and CD4+ T lymphocyte immunity . Furthermore, experiments in macrophage-depleted mice showed that CD8+ T lymphocyte responses were effectively induced in the absence of macrophages . Together, our results imply that in this infection model, SPI-1-mediated cell death does not affect the immunological defense response and is not important for the induction of CD8+ T lymphocyte responses. J Immunol, 2002 Sep 15, 169(6), 2846 - 50 Cutting edge: Salmonella AvrA effector inhibits the key proinflammatory, anti-apoptotic NF-kappa B pathway; Collier-Hyams LS et al.; Secreted prokaryotic effector proteins have evolved to modulate the cellular functions of specific eukaryotic hosts . Generally, these proteins are considered virulence factors that facilitate parasitism . However, in certain plant and insect eukaryotic/prokaryotic relationships, effector proteins are involved in the establishment of commensal or symbiotic interactions . In this study, we report that the AvrA protein from Salmonella typhimurium, a common enteropathogen of humans, is an effector molecule that inhibits activation of the key proinflammatory NF-kappaB transcription factor and augments apoptosis in human epithelial cells . This activity is similar but mechanistically distinct from that described for YopJ, an AvrA homolog expressed by the bacterial pathogen YERSINIA: We suggest that AvrA may limit virulence in vertebrates in a manner analogous to avirulence factors in plants, and as such, is the first bacterial effector from a mammalian pathogen that has been ascribed such a function. BMC Evol Biol . 2002 Sep 08;2(1):14. Carbon and nitrogen substrate utilization by archival Salmonella typhimurium LT2 cells; Tracy BS et al.; BACKGROUND: A collection of over 20,000 Salmonella typhimurium LT2 mutants, sealed for four decades in agar stabs, is a unique resource for study of genetic and evolutionary changes . Previously, we reported extensive diversity among descendants including diversity in RpoS and catalase synthesis, diversity in genome size, protein content, and reversion from auxotrophy to prototrophy . RESULTS: Extensive and variable losses and a few gains of catabolic functions were observed by this standardized method . Thus, 95 catabolic reactions were scored in each of three plates in wells containing specific carbon and nitrogen substrates . CONCLUSION: While the phenotype microarray did not reveal a distinct pattern of mutation among the archival isolates, the data did confirm that various isolates have used multiple strategies to survive in the archival environment . Data from the MacConkey plates verified the changes in carbohydrate metabolism observed in the Biolog system. Drug Metab Rev, 2002 Aug, 34(3), 667 - 76 Role of human cytochrome P450 (CYP) in the metabolic activation of nitrosamine derivatives: application of genetically engineered Salmonella expressing human CYP; Kamataki T et al.; The role of human cytochrome P450 (CYP) in the metabolic activation of tobacco-related N-nitrosamines was examined by Salmonella mutation test using a series of genetically engineered Salmonella typhimurium YG7108 strains each co-expressing a form of CYP (CYP1A1, CYP1A2, CYP1B1, CYP2A6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1, CYP3A4, and CYP3A5) together with human NADPH-cytochrome P450 reductase . Seven tobacco-related N-nitrosamines such as 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, N-nitrosodiethylamine, N-nitrosopyrrolidine, N-nitrosopiperidine, N-nitrosonornicotine, N-nitrosoanabasine, and N-nitrosoanatabine were used . The CYP2A6 was found to be responsible for the mutagenic activation of essentially all tobacco-related N-nitrosamines examined . On the basis of the evidence, genetic polymorphism of the CYP2A6 gene appeared to be one of the factors determining cancer susceptibility caused by smoking . Previously, we found the whole deletion of the CYP2A6 gene (CYP2A6*4C) as a type of genetic polymorphism in Japanese . We hypothesized that individuals possessing the gene homozygous for CYP2A6*4C were incapable of activating tobacco-related N-nitrosamines and showed lower susceptibility to lung cancer induced by tobacco smoke . Thus, the relationship between the CYP2A6*4C and the susceptibility to the lung cancer was evaluated . The frequency of the CYP2A6*4C was significantly lower in the lung cancer patients than healthy volunteers, suggesting that the subjects carrying the CYP2A6*4C alleles are resistant to carcinogenesis caused by N-nitrosamines because of the poor metabolic activation capacity . Taking these results into account, CYP2A6 is an enzyme enhancing lung cancer risk. Poult Sci, 2002 Aug, 81(8), 1224 - 30 Pulmonary hypertensive response to endotoxin in cellulose-primed and unprimed broiler chickens; Wang W et al.; Previous studies indicate that individual broilers vary widely in their pulmonary vascular responsiveness to i.v . injections of endotoxin . This individual variability may reflect differences acquired during previous respiratory challenges or genetic variability that may be associated with susceptibility to pulmonary hypertension syndrome (ascites) . In the present study, we compared the endotoxin responses of 4- to 5- wk-old control broilers (unprimed) and broilers in which the pulmonary vasculature had been immunologically challenged 48 h previously by an i.v . injection of cellulose micro-particles (primed) . The injected cellulose micro-particles are carried in the venous blood to the lungs, where they become trapped in the pulmonary vasculature and initiate acute focal inflammatory responses within the surrounding lung parenchyma . Physiological variables (respiratory rate, heart rate, pulmonary and systemic arterial pressures) were evaluated prior to and following the i.v . administration of 1 mg of Salmonella typhimurium endotoxin . Prior to endotoxin injection, the respiratory rate was higher in primed than in unprimed broilers; however, the heart rate, pulmonary arterial pressure, and systemic arterial pressure did not differ between groups . Broilers in both groups exhibited similar ranges of individual variability in their endotoxin responses . The overall time of onset, magnitude, and duration of the pulmonary hypertensive responses were similar for both groups . Accordingly, the initiation of a preexisting inflammatory response within the lung parenchyma did not alter the timing, amplitude, or variability of the subsequent pulmonary hypertensive response to endotoxin in broilers. Environ Mol Mutagen, 2002, 40(1), 63 - 70 Genotoxicity of 5-aminolevulinic and 4,