J Nutr, 2002 Mar, 132(3), 472 - 7 Dietary oligofructose and inulin protect mice from enteric and systemic pathogens and tumor inducers; Buddington KK et al.; Prebiotics induce changes in the population and metabolic characteristics of the gastrointestinal bacteria, modulate enteric and systemic immune functions, and provide laboratory rodents with resistance to carcinogens that promote colorectal cancer . There is less known about protection from other challenges . Therefore, mice of the B6C3F1 strain were fed for 6 wk a control diet with 100 g/kg cellulose or one of two experimental diets with the cellulose replaced entirely by the nondigestible oligosaccharides (NDO) oligofructose and inulin . From each diet, 25 mice were challenged by a promoter of colorectal cancer (1,2-dimethylhydrazine), B16F10 tumor cells, the enteric pathogen Candida albicans (enterically), or were infected systemically with Listeria monocytogenes or Salmonella typhimurium . The incidences of aberrant crypt foci in the distal colon after exposure to dimethylhdrazine for mice fed inulin (53%) and oligofructose (54%) were lower than in control mice (76%; P < 0.05), but the fructans did not reduce the incidence of lung tumors after injection of the B16F10 tumor cells . Mice fed the diets with fructans had 50% lower densities of C . albicans in the small intestine (P < 0.05) . A systemic infection with L . monocytogenes caused nearly 30% mortality among control mice, but none of the mice fed inulin died, with survival intermediate for mice fed oligofructose . Mortality was higher for the systemic infection of S . typhimurium (>80% for control mice), but fewer of the mice fed inulin died (60%; P < 0.05), with mice fed oligofructose again intermediate . The mechanistic basis for the increased resistance provided by dietary NDO was not elucidated, but the findings are consistent with enhanced immune functions in response to changes in the composition and metabolic characteristics of the bacteria resident in the gastrointestinal tract. Biochemistry, 2002 Mar 12, 41(10), 3520 - 8 Quinolinate phosphoribosyltransferase: kinetic mechanism for a type II PRTase; Cao H et al.; Quinolinate phosphoribosyltransferase (QAPRTase, EC 2.4.2.19) catalyzes the formation of nicotinate mononucleotide, carbon dioxide, and pyrophosphate from 5-phosphoribosyl 1-pyrophosphate (PRPP) and quinolinic acid (QA, pyridine 2,3-dicarboxylic acid) . The enzyme is the only type II PRTase whose X-ray structure is known . Here we determined the kinetic mechanism of the enzyme from Salmonella typhimurium . Equilibrium binding studies show that PRPP and QA each form binary complexes with the enzyme, with K(D) values (53 and 21 microM, respectively) similar to their K(M) values (30 and 25 microM, respectively) . Although neither PP(i) nor NAMN products bound well to the enzyme, 130-fold tighter binding of PP(i) (K(D) = 75 microM) and NAMN (K(D) = 6 microM) in a ternary complex was observed . Phthalic acid (K(D) = 21 microM) and PRPP each caused a 2.5-fold tightening of the other's binding . Isotope trapping experiments indicated that the E.QA complex is catalytically competent, whereas the E.PRPP complex could not be trapped . Pre-steady-state kinetics gave a linear rate of NAMN formation, indicating that on-enzyme phosphoribosyl transfer chemistry is rate-determining . Isotope trapping from the steady state revealed that nearly all QA and about one-third of PRPP in ternary enzyme.QA.PRPP complexes could be trapped as the product . Substrate inhibition by PRPP was observed . These data demonstrate a predominantly ordered kinetic mechanism in which productive binding of quinolinic acid precedes that of PRPP . An E.PRPP complex exists as a nonproductive side branch. Zhonghua Yu Fang Yi Xue Za Zhi, 1999 Jan, 33(1), 34 - 6 {Expression and stability of fragment of Plasmodium merozoite major surface protein 1 in recombinant attenuated Salmonella typhimurium}; Qian F et al.; OBJECTIVE: To determine the invasive ability of recombinant attenuated Salmonella typhimurium X4064 (pQEM1) strain containing gene fragment of Plasmodium falciparium merozoite surface protein 1 (MSP1), the stability of its plasmid, and its re-expression . METHODS: BALB/c mice were fed with recombinant attenuated S . typhimurium containing No . 1 gene fragment of P . falciparium MSP1 by gastric tube . Plate incubation, plasmid endonuclease analysis and Western blot were used to identify the recombinant attenuated S . typhimurium strains isolated from mice and the ability of re-expression, and its growth were determined in vitro . RESULTS: The attenuated strain X4064 of S . typhimurium isolated from mice contained recombinant plasmid pQEM1, no . 1 MSP1 fragment of P . falciparium was expressed in vitro in S . typhimurium X4064 (pQEM1) strain, and its growth curve of X4064 (pQEM1) strain in mice was basically similar to that of X4064 . CONCLUSION: The recombinant plasmid pQEM1 could steadily exist in the X4064 strain of S . typhimurium, without influence on its invasion into host cells . X4060 (pQEM1) strain isolated from infected mice still had the ability to re-express M1 protein. J Immunol, 2002 Mar 1, 168(5), 2415 - 23 Serpin 2a is induced in activated macrophages and conjugates to a ubiquitin homolog; Hamerman JA et al.; After i.p . infection of mice with the intracellular bacterium Mycobacterium bovis bacillus Calmette-Guerin, macrophages recovered from the peritoneal cavity display classical signs of immune activation . We have identified a member of the serine protease inhibitor (serpin) family which is highly induced in macrophages during bacillus Calmette-Guerin infection . Serpin 2a (spi2a) expression is also induced in macrophages in vivo during infection with Salmonella typhimurium and Listeria monocytogenes, and in vitro by a variety of bacteria and bacterial products . The cytokine IFN-gamma also induces spi2a expression in macrophages, and this induction is synergistic with bacterial products . We also demonstrate here that a ubiquitin homolog, IFN-stimulated gene of 15-kDa (ISG15), is strongly induced during in vitro and in vivo activation of macrophages and that it conjugates to spi2a in activated macrophages . The ISG15-spi2a conjugates were identified by tandem mass spectrometry and contained spi2a conjugated to either one or two molecules of ISG15 . Whereas spi2a was induced by either bacterial products or IFN-gamma, ISG15 was induced only by bacterial products . Although many protein targets have been described for ubiquitin conjugation, spi2a is the first ISG15-modified protein to be reported . Macrophage activation is accompanied by the activation of a variety of proteases . It is of interest that a member of the serine protease inhibitor family is concomitantly induced and modified by a ubiquitin-like protein. Eur J Med Chem, 2002 Feb, 37(2), 127 - 33 Quantitative structure--activity relationships of antimutagenic benzalacetones and 1,1,1-trifluoro-4-phenyl-3-buten-2-ones; Yamagami C et al.; The antimutagenic activities (IC(50)) of benzalacetones (BZ) and 1,1,1-trifluo-4-phenyl-3-buten-2-ones (TF) against UV-induced mutagenesis in Escherichia coli WP2s(uvrA trpE) were quantitatively analyzed in terms of physicochemical parameters by regression analyses . Structural requirements for maximal potency were derived from the results of quantitative structure--activity relationship (QSAR) analyses: (1) ring substituents should be electron-withdrawing; (2) 2-OH substituents incapable of intramolecular hydrogen-bonding notably increase the potency; and (3) replacement of CH(3) group by CF(3) in the side chain enhances the activity . Contrary to our expectations, the best correlation lacked hydrophobic effects . Antimutagenic activities against gamma-induced mutagenesis in Salmonella typhimurium TA2638 were also studied for some derivatives in the BZ series, where, in addition to electronic and hydrogen-bonding factors, a hydrophobic term was also significant . Physicochemical meanings of the derived correlations are discussed. Eur J Biochem, 2002 Jan, 269(2), 443 - 50 Structure of peptidase T from Salmonella typhimurium; Hakansson K et al.; The structure of peptidase T, or tripeptidase, was determined by multiple wavelength anomalous dispersion (MAD) methodology and refined to 2.4 A resolution . Peptidase T comprises two domains; a catalytic domain with an active site containing two metal ions, and a smaller domain formed through a long insertion into the catalytic domain . The two metal ions, presumably zinc, are separated by 3.3 A, and are coordinated by five carboxylate and histidine ligands . The molecular surface of the active site is negatively charged . Peptidase T has the same basic fold as carboxypeptidase G2 . When the structures of the two enzymes are superimposed, a number of homologous residues, not evident from the sequence alone, could be identified . Comparison of the active sites of peptidase T, carboxypeptidase G2, Aeromonas proteolytica aminopeptidase, carboxypeptidase A and leucine aminopeptidase reveals a common structural framework with interesting similarities and differences in the active sites and in the zinc coordination . A putative binding site for the C-terminal end of the tripeptide substrate was found at a peptidase T specific fingerprint sequence motif. Drug Chem Toxicol, 2002 Feb, 25(1), 93 - 107 Lack of DNA binding in the rat nasal mucosa and other tissues of the nasal toxicants roflumilast, a phosphodiesterase 4 inhibitor, and a metabolite, 4-amino-3,5-dichloropyridine, in contrast to the nasal carcinogen 2,6-dimethylaniline; Jeffrey AM et al.; The phosphodiesterase 4 inhibitor Roflumilast (B9302-107) (RF) and its metabolite 4-amino-3,5-dichloropyridine (ADCP) produced nasal toxicity in preclinical safety studies with rats . The purpose of this study was to assess the possible formation of DNA adducts, by RF and ADCP, in the nasal mucosa, liver and testes of male rats using the 32P-postlabeling assay . For comparison, rats were exposed to the DNA-reactive carcinogens 2,6-dimethylaniline (DMA), also known as 2,6-xylidine, a nasal carcinogen, and the aromatic amine carcinogens 4,4'-methylene-bis(2-chloroaniline) (MOCA), which yields monocyclic DNA adducts, and 2-acetylaminofluorene (2-AAF) . In the case of RF, possible sources of DNA adducts include the parent molecule and its ADCP moiety by enzymatic N-hydroxylation and sulfation, reactions typical of carcinogenic aromatic amines . 4-Acetoxylamino-3,5-dichloropyridine (N-acetoxy-ADCP), a chemically activated derivative of ADCP, was prepared and used to modify DNA which was then used to establish the chromatographic conditions with which to reliably detect whether or not such adducts were formed metabolically from RF and ADCP . Similarly, a standard N-hydroxy-DMA was prepared, but the corresponding N-acetoxy derivative was unstable and decomposed during synthesis . Both N-hydroxy-DMA and N-acetoxy-ADCP were mutagenic in the Salmonella typhimurium Ames assay using strain TA100 without an exogenous bioactivation system, with the former being more potent . N-hydroxy-ADCP was essentially inactive in this assay . For the 32P-postlabeling assay, male Wistar rats were exposed to the test substances and carrier control compounds by intragastric instillation at the selected dose levels for 7 days . Subsequently, the nasal mucosa, liver, and testes of the rats exposed to the test or control compounds were extirpated, the DNA extracted and the samples postlabeled . The patterns of adducts formed with the test compounds were compared to those formed in N-acetoxy-ADCP- and N-hydroxy-DMA-adducted DNA, which were assayed by both nuclease P1 and butanol enhancement methods . Based upon the similarity of results from the two enhancement methods, only the former was used for the in vivo studies . No evidence was obtained for the formation of DNA adducts from RF or its metabolites, specifically ADCP, under the conditions of these assays despite the ability to detect adducts from DNA modified chemically with N-acetoxy-ADCP and DNA adducts from the other compounds in their target organs . In the absence of a pattern of compound-related spots, we conclude that RF does not form DNA adducts having the potential to initiate neoplasia in these three tissues. Prev Vet Med, 2002 Jan 22, 52(3-4), 251 - 65 Qualitative and quantitative risk assessment for human salmonellosis due to multi-resistant Salmonella Typhimurium DT104 from consumption of Danish dry-cured pork sausages; Alban L et al.; Salmonella Typhimurium DT104 (DT104) is unwanted in products for human consumption due to its antibiotic resistance and ability to cause disease . We intended to set up an improved monitoring and management program to aid in deciding when to use pork contaminated with DT104 for production of sausages without jeopardizing consumer safety . We started by carrying out two assessments of the risk for human health associated with consumption of sausages produced by: (1) Danish pork from average slaughter days; (2) imported pork (IMP) with average prevalence of DT104 . The assessments showed that, if Salmonella is present, it is usually in lower numbers (< or =50 per 400 cm(2) surface) . Additionally, during processing, the numbers will be reduced by at least 2 log-units . In Danish (DK) pork, DT104 constitutes 0.2-1.0% of the Salmonella isolates reported, while in imported pork (IMP), 18% . We estimated that out of one million, 25 g servings of DK dry-cured sausages, up to two DT104 bacteria could be found in each of 245 servings . Out of one million servings of 25 g IMP dry-cured sausages, up to two DT104 bacteria would occur in each of 19,260 servings. Mol Microbiol, 2002 Jan, 43(1), 95 - 106 A potential role for periplasmic superoxide dismutase in blocking the penetration of external superoxide into the cytosol of Gram-negative bacteria; Korshunov SS et al.; Superoxide is a key component of the antibacterial weaponry of phagocytes . Presumably, for this reason, strains of Salmonella typhimurium express a periplasmic superoxide dismutase (SOD) that is essential for full virulence . Because most anions cannot easily penetrate lipid membranes, it is thought that the phagosomal superoxide either damages an unknown target on the bacterial surface or reacts with nitric oxide to form peroxynitrite (HOONO), a toxic oxidant that can freely enter bacteria . However, in this study, we tested whether superoxide itself could penetrate membranes . Superoxide that was generated at high pH (>7.5) very slowly reduced cytochrome c that was encapsulated inside lipid vesicles . It did so much more quickly at lower pH (<7) . Under the latter conditions, more superoxide was protonated and uncharged (HO2*), and the penetrance of superoxide was proportional to the concentration of this species . The permeability coefficient of HO2* was determined to be 9 x 10(-4) cm sec(-1), just slightly lower than that of water and far higher than the value of the anionic form (O2-, <10(-7) cm sec(-1) . When Escherichia coli mutants that lack periplasmic SOD were exposed to super-oxide at pH 6.5, cytosolic fumarase B was damaged . Damage was minimal at higher pH or in strains that contained periplasmic SOD . Thus, in the acidic phagolysosome, superoxide may be able to penetrate and attack cytosolic targets of captive bacteria . This process may contribute to the potency of the oxidative burst . One role of periplasmic SOD may be to avert this damage . In contrast, periplasmic SOD was ineffective at lowering the extracellular super-oxide concentration and, therefore, may have little impact upon HOONO formation. Lett Appl Microbiol, 2002, 34(1), 62 - 6 Development of membrane filter holder (MFH) method for recovery of heat-injured Escherichia coli O157:H7 and Salmonella typhimurium; Kang DH; AIMS: A method of recovering sublethally heat-injured bacteria was developed with specific apparatus (membrane filter holder; MFH) which was originally used for Iso-Grid Hydrophobic membrane . filter holder . METHODS AND RESULTS: The procedure used a non-selective agar underlayed with a selective medium with a MFH . A non-selective agar was poured on upper part (compartment A) of MFH, and then injured foodborne pathogens were inoculated on the non-selective medium . After 3-h repair incubation period, selective agar was added to the bottom of the chamber (compartment B) of the MFH and further incubated . By diffusing through the non-selective top agar, selective agents from the underlay medium impart selectivity to the system . CONCLUSIONS: Using the MFH method, recovery of heat-injured foodborne pathogens (Escherichia coli O157:H7 and Salmonella typhimurium) were not different (P > 0.05) from recoveries with non-selective media (TSA) . However, the recoveries of foodborne pathogens on MFH were significantly higher (P < 0.05) than those of direct plating on selective medium such as SMAC (MacConkey Sorbitol Agar) or XLD (Xylose Lysine Desoxycholate) . SIGNIFICANCE AND IMPACT OF THE STUDY: In conclusion, the MFH method is a simple and convenient method for recovery of heat-injured foodborne pathogens. Chem Res Toxicol, 2002 Feb, 15(2), 198 - 208 Characterization of DNA adducts derived from syn-benzo{ghi}fluoranthene-3,4-dihydrodiol-5,5a-epoxide and comparative DNA binding studies with structurally-related anti-diolepoxides of benzo{ghi}fluoranthene and benzo{c}phenanthrene; Chang HF et al.; This paper reports structural characterization of the adducts and tetraols formed from syn-benzo{ghi}fluoranthene-3,4-dihydrodiol-5,5a-epoxide (syn-B{ghi}FDE, 3) and comparative DNA-binding and mutagenicity studies involving 3, anti-B{ghi}FDE (2), and anti-benzo{c}phenanthrene-11,12-dihydrodiol-13,14-epoxide (anti-BcPDE, 5) . The structures of nine DNA adducts and two racemic tetraols derived from 3 have been determined spectroscopically . Similar characterization of adducts obtained from the anti-isomer 2 was described in the preceding paper in this issue {Chang et al . (2002) Chem . Res . Toxicol . 15, 187-197} . The majority of DNA adducts with 3 are those from the trans- or cis-opening of the epoxide at C5a by the exocyclic amino groups of dG, dA, and dC . The diolepoxides 2 and 3 are rigid structure analogues of anti- and syn-BcPDE (5 and 6), respectively, thus serving as models for probing molecular deformity and diol conformation in diolepoxide-DNA interaction . Comparative DNA binding experiments indicate that 57% of 2 and 33% of 3 were converted into DNA adducts, whereas a 71% conversion was observed for 5 . In general, lower percentages were observed with denatured calf-thymus DNA . As for base selectivity, 2 showed a greater affinity for dA relative to dG (dA/dG ratio, 0.79) than 3 (0.56) when reacted with native calf-thymus DNA . A much higher dA/dG ratio (1.41) was obtained for 5 . The overall dA/dG ratios were lower with denatured DNA, indicating the importance of the secondary structure of DNA for both adduct formation and chemical selectivity . The T-shape pseudo-diaxial diols of 3 appears to have favorable electrostatic interactions with the nearby phosphate backbone in the minor groove of DNA, thereby yielding greater amounts of dG adducts than the pseudo-diequatorial 2 . The anti-isomer 2 was found to be seven times more mutagenic than 3, but they are significantly less mutagenic than the nonplanar analogue 5 when tested in Salmonella typhimurium TA 100. Chem Res Toxicol, 2002 Feb, 15(2), 140 - 52 Structure of the 1,N(2)-propanodeoxyguanosine adduct in a three-base DNA hairpin loop derived from a palindrome in the Salmonella typhimurium hisD3052 gene; Weisenseel JP et al.; The solution structure of the 1,N(2)-propanodeoxyguanosine (PdG) adduct was determined in a 3-base hairpin loop formed by d(CGCGGTXTCCGCG) (X = PdG) . This sequence is contained within the Salmonella typhimurium hisD3052 gene, a hotspot for frameshift mutagenesis . PdG provides a structural model for the primary adduct induced in DNA by malondialdehyde, the 3-(2'-deoxy-beta-D-erythro-pentofuranosyl)pyrimido{1,2-a}-purin-10(3H)-one (M(1)G) lesion . The solution structure of the PdG-containing hairpin was refined by molecular dynamics calculations restrained by a combination of NMR-derived distances and dihedral angles, using a simulated annealing protocol . The structure of the PdG-modified hairpin consisted of a five-base-pair stem and a three-base loop consisting of T(6), X(7), and T(8) . T(6) projected into the minor groove of the stem adjacent to G(4) . The modified base X(7) stacked on top of the duplex stem and wedged between bases T(8) and C(9) . The PdG moiety was oriented such that the imidazole proton was facing the minor groove of the stem and the exocyclic protons projected into the major groove . The structure of the adducted hairpin was compared with the structure of the corresponding unmodified oligodeoxynucleotide, and was found to be similar . There was a minor difference in the backbone angles of the G and PdG Hairpins at the phosphate linkage between G(5) and T(6) involving the G(5) epsilon angle and T(6) alpha and beta angles . The PdG-modified hairpin exhibited an increase in T(m) of approximately 2 degrees C compared to the unmodified hairpin . The structural and thermodynamic similarities suggested that PdG does not stabilize this hairpin and thus may not promote its extrusion in duplex DNA . The structural results are correlated with the results of site-specific mutagenesis experiments in the same sequence, which do not show evidence of frameshift mutations associated with hairpin loop formation . The geometry of this three-base loop is similar to that of other DNA hairpins containing three-base loops, and suggests a common motif for the folding of these loops. Chem Res Toxicol, 2002 Feb, 15(2), 127 - 39 Structure of an oligodeoxynucleotide containing a 1,N(2)-propanodeoxyguanosine adduct positioned in a palindrome derived from the Salmonella typhimurium hisD3052 gene: Hoogsteen pairing at pH 5.2; Weisenseel JP et al.; The structure of the 1,N(2)-Propanodeoxyguanosine (PdG) adduct was determined at pH 5.2 in the oligodeoxynucleotide duplex 5'-d(CGCGGTXTCCGCG)3'.5'-d(CGCGGACACCGCG)-3' (X = PdG) . This sequence, referred to as the -TXT- sequence, is contained within the Salmonella typhimurium hisD3052 gene and contains a palindrome, representing a potential hotspot for frameshift mutagenesis . PdG provides a model for the primary adduct induced in DNA by malondialdehyde, the 3-(2'-deoxy-beta-D-erythro-pentofuranosyl)pyrimido{1,2-a}-purin-10(3H)-one (M(1)G) lesion . The solution structure was refined by molecular dynamics calculations restrained by a combination of NMR-derived distances and dihedral angles, using a simulated annealing protocol . PdG introduced a localized perturbation into the sequence at base pair X(7).C(20), which was pH-dependent . At neutral pH, conformational exchange resulted in spectral line broadening, and it was not possible to determine the structure . A stable structure was observed at pH 5.2 in which PdG rotated about the glycosyl bond into the syn conformation . This placed the exocyclic moiety into the major groove of the duplex . PdG formed a protonated Hoogsteen pair with nucleotide C(20) in the complementary strand . The pseudorotation of the deoxyribose at C(20) was altered to an approximately equal blend of C2'-endo and C3'-endo structures . However, these made little difference in the overall structure of the modified oligodeoxynucleotide . The structure was compared to that of PdG in the 5'-d(CGCXCGGCATG)-3'.5'-(CATGCCGCGCG)-3' sequence (the -CXC- sequence) at pH 5.8 {Singh, U . S., Moe, J . G., Reddy, G . R., Weisenseel, J . P., Marnett, L . J., and Stone, M . P . (1993) Chem . Res . Toxicol . 6, 825-836} . A sequence effect was observed . When PdG was placed into the -TXT- sequence at low pH, the structural perturbation was limited to the X(7).C(20) base pair . In contrast, when PdG was placed into the -CXC- sequence at low pH, both the modified base pair and its 3'-neighbor base pair were disrupted . The results are discussed in the context of differential outcomes for site-specific mutagenesis and replication bypass experiments when PdG was placed in the -TXT- and -CXC- sequences, respectively. J Food Prot, 2002 Feb, 65(2), 403 - 7 Occurrence of Salmonella enterica serotype typhimurium DT104A in retail ground beef; Zhao T et al.; Surveillance data of cattle and human isolates of Salmonella enterica serovar Typhimurium DT104 indicate that this pathogen emerged worldwide in the 1980s, particularly in cattle . Studies were conducted to determine the prevalence of Salmonella Typhimurium DT104 in ground beef . Samples were also tested for the presence of generic Escherichia coli . A total of 404 fresh ground beef samples obtained at retail stores from New York, San Francisco, Philadelphia, Denver, Atlanta, Houston, and Chicago were shipped overnight to Georgia for processing . Salmonella spp . were isolated from 14 (3.5%) samples . Eight different serotypes were identified among the isolates, including Salmonella Typhimurium (5), Salmonella Lille (3), Salmonella Montevideo (1), Salmonella Hadar (1), Salmonella Meleagridis (1), Salmonella Cerro (1), Salmonella Kentucky (1), and Salmonella Muenster (1) . Antibiotic resistance profiles indicated that all five Salmonella Typhimurium isolates were resistant to ampicillin, streptomycin, sulfamethoxazole, ticarcillin, and tetracycline but that they were sensitive to chloramphenicol . Phage typing revealed that all five Salmonella Typhimurium isolates were DT104A, a subtype of DT104 . All five Salmonella Typhimurium DT104A isolates were obtained from ground beef sampled from retail outlets in San Francisco . Pulsed-field gel electrophoresis (PFGE) genomic DNA profiles of the five Salmonella Typhimurium DT104A isolates from ground beef were indistinguishable from those of four control Salmonella Typhimurium DT104 penta-resistant isolates from cattle that were used for comparison . A total of 102 generic E . coli isolates were obtained, only three of which were multiresistant to antibiotics . In addition, three E . coli isolates were recovered from samples that were positive for Salmonella Typhimurium DT104A . No correlation of antibiotic resistance profiles was observed between Salmonella Typhimurium DT104A and generic E . coli, as two of the three E . coli isolates were susceptible to all of the antibiotics tested, and the third isolate was resistant only to cephalothin . These data indicate that Salmonella Typhimurium DT104A can be isolated from retail ground beef, and because there was little overlap in antibiotic resistance patterns between Salmonella Typhimurium DT104A and E . coli isolates from the same ground beef samples, these limited data suggest that the transfer of antibiotic resistance genes among enteric bacteria in ground beef may not be common . This latter observation is further supported by the limited isolation of multiantibiotic-resistant E . coli from retail ground beef. J Food Prot, 2002 Feb, 65(2), 284 - 90 Prevalence and antibiotic susceptibility of Salmonella isolated from beef animal hides and carcasses; Bacon RT et al.; This study determined the prevalence of Salmonella on beef animal hides and carcasses and antimicrobial susceptibility profiles against a panel of 13 antibiotics . In each of the eight commercial packing facilities, of which five processed primarily heifers and steers and the remaining three processed primarily cows and bulls, hide and carcass sponge swab samples were obtained immediately before hide removal and before carcass chilling, respectively . Overall, prevalence of Salmonella on external surfaces (hides) of cattle was 15.4% (49 of 319), whereas prevalence after dehiding and other slaughtering/dressing processes, including the application of decontamination treatments, was, as expected, reduced (P < 0.05) to 1.3% (4 of 320) on carcass surfaces . From 53 total Salmonella-positive hide and carcass samples, 526 biochemically confirmed isolates were obtained to determine antimicrobial susceptibility profiles . Of 53 Salmonella-positive samples, individually, 24 (45.3%), 17 (32.1%), 17 (32.1%), 11 (20.8%), 8 (15.1%), 8 (15.1%), 8 (15.1%), 4 (7.5%), and 2 (3.8%) samples yielded at least one isolate resistant to amoxicillin/clavulanic acid, tetracycline, streptomycin, sulfonamides, ampicillin, ampicillin/sulbactam, chloramphenicol, gentamicin, and trimethoprim/sulfamethoxazole, respectively . None of the Salmonella-positive samples yielded an isolate resistant to ceftriaxone, ciprofloxacin, enrofloxacin, or levofloxacin . Although none of the samples yielded an isolate simultaneously resistant to three or four antimicrobials, a total of eight samples yielded at least one isolate resistant to five or more antimicrobials tested . Included among the 18 group B-positive samples were three samples that, individually, yielded at least one Salmonella Typhimurium var . Copenhagen DT104 isolate resistant to at least six antimicrobials tested . Results from this study support current prudent therapeutic and subtherapeutic antimicrobial use recommendations. Structure (Camb), 2002 Feb, 10(2), 225 - 35 Crystal structure of 4-amino-5-hydroxymethyl-2-methylpyrimidine phosphate kinase from Salmonella typhimurium at 2.3 A resolution; Cheng G et al.; The crystal structures of Salmonella typhimurium 4-amino-5-hydroxymethyl-2-methylpyrimidine phosphate kinase (HMPP kinase) and its complex with substrate HMP have been determined . HMPP kinase catalyzes two separate ATP-dependent phosphorylation reactions and is an essential enzyme in the thiamin biosynthetic pathway . HMPP kinase is a homodimer with one active site per monomer and is structurally homologous to members of the ribokinase family . A comparison of the structure of HMPP kinase with other members of the ribokinase family suggests an evolutionary progression . Modeling studies suggest that HMPP kinase catalyzes both of its phosphorylation reactions using in-line displacement mechanisms . We propose that the active site accommodates the two separate reactions by providing two different binding modes for the phosphate group of HMP phosphate. Cell Mol Biol (Noisy-le-grand), 2001 Nov, 47(7), 1115 - 20 Salmonella-mediated mucosal cell-mediated immunity; Lillard JW Jr et al.; Oral immunization with the recombinant Salmonella typhimurium strain (BRD 847) expressing the C fragment of tetanus toxin (TT) induces brisk Ag-specific mucosal S-IgA and serum Ab responses characterized by strong IgG2a Abs to the encoded antigen . We have constructed an attenuated Salmonella typhimurium (aroA- aroD-) strain that expresses chicken egg albumin (OVA) to further elucidate the role of Salmonella-induced Th1 cell phenotype on mucosal cell-mediated immunity (CMI) . Peyer's patches and spleen lymphocytes from mice that received the oral Salmonella-OVA vaccine showed dramatic increases in the percent cell lysis of the H-2b restricted EG7.OVA tumor cell line . These results indicate that a single dose of rSalmonella vaccine antigen vector is required to illicit systemic and mucosal Th1-type responses and CTLs . These results also support the existence of a highly regulated relationship between specific cell-mediated immunity and a branch of the humoral immune system, i.e . mucosal IgA responses. Teratog Carcinog Mutagen, 2002, 22(2), 113 - 28 Analysis of the cytotoxicity and mutagenicity of drinking water disinfection by-products in Salmonella typhimurium; Kargalioglu Y et al.; We analyzed the cytotoxicity and mutagenicity of the drinking water disinfection by-products (DBPs) bromoform (BF), bromoacetic acid (BA), dibromoacetic acid (DBA), tribromoacetic acid (TCA), chloroform (CF), chloroacetic acid (CA), dichloroacetic acid (DCA), trichloroacetic acid (TCA), 3-chloro-4-(dichloromethyl)-5-hydroxy-2{5H}-furanone (MX), and potassium bromate (KBrO3) in Salmonella typhimurium strains TA98, TA100, and RSJ100 +/- S9 . Solvent controls of DMSO and ethanol and a positive control of ethylmethanesulfonate (EMS) were also analyzed . We developed a rapid microplate-based method to determine the cytotoxicity of the DBPs and we determined their mutagenic potencies . The distributions of the rank order for the cytotoxicity and mutagenicity of these DBPs were compared and the structure-function relationships were identified . TA100 -S9 was the most sensitive strain for these DBPs . The rank order of the mutagenic potency adjusted with a cytoxicity factor was MX > BA > EMS > DBA > DCA > CA with TBA, TCA, BF, and CF not mutagenic . From a structure-function perspective, the brominated acetic acids were more cytotoxic and mutagenic than their chlorinated analogs . BA was 150x more mutagenic than CA . The mutagenic potency of the haloacetic acids was inversely related to the number of halogen atoms of the molecule . BA was 36x more mutagenic than DBA . The differential cytotoxicity expressed by the DBPs indicated that a cytotoxicity analysis enhanced the sensitivity of the mutagenicity data, which resulted in an enhanced precision for comparing their relative mutagenic strengths . This information is critical when conducting quantitative structure-function analysis of these hazardous agents . Ann Rheum Dis, 2002 Mar, 61(3), 264 - 6 Reactive arthritis following an outbreak of Salmonella typhimurium phage type 193 infection; Hannu T et al.; OBJECTIVES: To determine the occurrence and the clinical picture of reactive arthritis (ReA) following an outbreak of Salmonella typhimurium . METHODS: An outbreak of S typhimurium phage type DT 193 occurred in several municipalities in Finland in 1999 . A questionnaire which had a specific emphasis on musculoskeletal symptoms was mailed to all 78 subjects with a positive stool culture . Based on the answers, all subjects with recent joint complaints were clinically examined or interviewed by telephone . RESULTS: Sixty three of 78 subjects (81%) returned the questionnaire . Of these 63 subjects, five (8%) fulfilled the criteria for ReA . All the five subjects with ReA were adults with oligo- or polyarthritis . The antigen HLA-B27 was positive in two of the four subjects tested . In two of five subjects with ReA, the duration of acute arthritis was over six months . Subjects who had received antimicrobial drugs developed acute musculoskeletal symptoms significantly (p=0.013) less often than those without such treatment . None of the subjects with ReA had received antimicrobial drugs before the onset of joint symptoms . CONCLUSIONS: The occurrence of ReA following an outbreak of S typhimurium was at the same level as in outbreaks due to other salmonella serotypes reported previously by us, indicating that the frequency of ReA after various outbreaks is approximately 10% . Early use of antimicrobial drugs may prevent the development of musculoskeletal symptoms. Biochem Biophys Res Commun, 2002 Feb 15, 291(1), 116 - 23 3D model of human arylamine N-acetyltransferase 2: structural basis of the slow acetylator phenotype of the R64Q variant and analysis of the active-site loop; Rodrigues-Lima F et al.; The human arylamine N-acetyltransferase NAT2 is responsible for the biotransformation of numerous arylamine drugs and carcinogens . A common polymorphism of the NAT2 gene has been associated with susceptibility to drug toxicity and various malignancies . In this study, we used the crystal structure of the Salmonella typhimurium NAT (StNAT) to construct a high-quality model of a catalytic N-terminal region of NAT2 (residues 34-131) . We show that this region has a similar structure in StNAT and the human isoforms NAT1 and NAT2 . Comparison of the structures of these three molecules suggests that NATs have an active-site loop with a conserved structure, which is involved in substrate recognition . Our model is consistent with previous experimental data and provides the first plausible structural basis of the effects of a common genetic polymorphism (Arg(64)-->Gln) on NAT2 activity . (c)2002 Elsevier Science (USA). J Mol Biol, 2002 Feb 1, 315(5), 975 - 94 Bacteriophage p22 portal vertex formation in vivo; Moore SD et al.; Bacteriophage with double-stranded, linear DNA genomes package DNA into pre-assembled icosahedral procapsids through a unique vertex . The packaging vertex contains an oligomeric ring of a portal protein that serves as a recognition site for the packaging enzymes, a conduit for DNA translocation, and the site of tail attachment . Previous studies have suggested that the portal protein of bacteriophage P22 is not essential for shell assembly; however, when assembled in the absence of functional portal protein, the assembled heads are not active in vitro packaging assays . In terms of head assembly, this raises an interesting question: how are portal vertices defined during morphogenesis if their incorporation is not a requirement for head assembly? To address this, the P22 portal gene was cloned into an inducible expression vector and transformed into the P22 host Salmonella typhimurium to allow control of the dosage of portal protein during infections . Using pulse-chase radiolabeling, it was determined that the portal protein is recruited into virion during head assembly . Surprisingly, over-expression of the portal protein during wild-type P22 infection caused a dramatic reduction in the yield of infectious virus . The cause of this reduction was traced to two potentially related phenomena . First, excess portal protein caused aberrant head assembly resulting in the formation of T=7 procapsid-like particles (PLPs) with twice the normal amount of portal protein . Second, maturation of the PLPs was blocked during DNA packaging resulting in the accumulation of empty PLPs within the host . In addition to PLPs with normal morphology, smaller heads (apparently T=4) and aberrant spirals were also produced . Interestingly, maturation of the small heads was relatively efficient resulting in the formation of small mature particles that were tailed and contained a head full of DNA . These data suggest that incorporation of portal vertices into heads occurs during growth of the coat lattice at decision points that dictate head assembly fidelity . Microbes Infect, 2002 Jan, 4(1), 75 - 82 Assembly of the type III secretion needle complex of Salmonella typhimurium; Kimbrough TG et al.; The type III secretion needle complex (NC) of Salmonella typhimurium is a complex secretory system that functions to translocate virulence proteins into eukaryotic cells . Evolutionarily it is related to bacterial flagella . Assembly of the NC occurs through ordered secretion, polymerization, and assembly, and requires the coordinated expression and association of over 20 different proteins . Recent progress in the understanding of the assembly and architecture of the NC is reviewed. J Biol Chem, 2002 Apr 12, 277(15), 13346 - 53 Epub 2002 Jan 30. The Salmonella typhimurium flagellar basal body protein FliE is required for flagellin production and to induce a proinflammatory response in epithelial cells; Reed KA et al.; During apical colonization by Salmonella typhimurium, intestinal epithelial cells orchestrate a proinflammatory response that involves secretion of chemoattractants, predominantly interleukin-8, which coordinate neutrophil trans-epithelial migration at the site of infection . This host-pathogen interaction requires several S . typhimurium genes . To identify novel genes that participate in this pathogen-induced proinflammatory response, we created S . typhimurium Tn-10 transposon mutants and identified a single mutant with Tn-10 insertional inactivation within the fliE flagellar locus that was able to adhere to and invade intestinal epithelial cells normally but was unable to induce interleukin-8 secretion in host cells . The fliE-deficient mutant failed to secrete flagellin and lacked any surface assembly of flagellae . Unlike wild-type S . typhimurium, the fliE-deficient mutant did not activate the IkappaBalpha/NF-kappaB signaling pathway or induce the coordinated trans-epithelial migration of isolated human neutrophils . Transcomplementation of the fliE-deficient mutant with a wild-type fliE-harboring plasmid restored all defects and produced a wild-type S . typhimurium phenotype . Furthermore, functional down-regulation of basolateral TLR5 completely inhibited the monolayers' ability to respond to both wild-type S . typhimurium and purified flagellin but had no affect on tumor necrosis factor alpha-induced responses . We therefore conclude that S . typhimurium fliE is essential for flagellin secretion, flagellar assembly, and S . typhimurium-induced proinflammatory responses through basolateral TLR5 and is consistent with the emerging model of S . typhimurium flagellin-induced inflammation. J Biol Chem, 2002 May 24, 277(21), 18753 - 62 Epub 2002 Jan 30. Macrophages inhibit Salmonella typhimurium replication through MEK/ERK kinase and phagocyte NADPH oxidase activities; Rosenberger CM et al.; Host responses during the later stages of Salmonella-macrophage interactions are critical to controlling infection but have not been well characterized . After 24 h of infection, nearly half of interferon-gamma-primed murine RAW 264.7 macrophage-like cells infected by Salmonella enterica serovar Typhimurium contained filamentous bacteria . Bacterial filamentation indicates a defect in completing replication and has been previously observed in bacteria responding to a variety of stresses . To understand whether macrophage gene expression was responsible for this effect on Salmonella Typhimurium replication, we used gene arrays to profile interferon-gamma-primed RAW 264.7 cell gene expression following infection . We observed an increase in MEK1 kinase mRNA at 8 h, an increase in MEK protein at 24 h, and measured phosphorylation of MEK's downstream target kinase, ERK1/2, throughout the 24-h infection period . Treatment of cells with MEK kinase inhibitors significantly reduced numbers of filamentous bacteria observed within macrophages after 24 h and increased the number of intracellular colony-forming units . Phagocyte NADPH oxidase inhibitors and antioxidants also significantly reduced bacterial filamentation . Either MEK kinase or phagocyte oxidase inhibitors could be added 4-8 h after infection and still significantly decrease bacterial filamentation . Oxidase activity appears to mediate bacterial filamentation in parallel to MEK kinase signaling, while inducible nitric-oxide synthase inhibitors had no significant effect on bacterial morphology . In summary, Salmonella Typhimurium infection of interferon-gamma-primed macrophages triggers a MEK kinase cascade at later infection times, and both MEK kinase and phagocyte NADPH oxidase activity impair bacterial replication . These two signaling pathways mediate a host bacteriostatic pathway and may play an important role in innate host defense against intracellular pathogens. J Biol Chem, 2002 Apr 12, 277(15), 12770 - 6 Epub 2002 Jan 30. Role of 3-phosphoinositides in the maturation of Salmonella-containing vacuoles within host cells; Scott CC et al.; Salmonella typhimurium invades mammalian cells and replicates within a vacuole that protects it from the host's microbicidal weapons . The Salmonella-containing vacuole (SCV) undergoes a remodelling akin to that of the host cell's endocytic pathway, but SCV progression is arrested prior to fusion with lysosomes . We studied the role of phosphatidylinositol 3-kinase (PI3-K) in SCV maturation within HeLa cells . Phosphatidylinositol 3-phosphate (PI3P), monitored in situ using fluorescent conjugates of FYVE or PX domains, was found to accumulate transiently on the SCV . Wortmannin prevented PI3P accumulation and the recruitment of EEA1 but did not affect the association of Rab5 with the SCV . Importantly, inhibition of PI3-K also impaired fusion of the SCV with vesicles containing LAMP-1 . Rab7, which is thought to be required for association of LAMP-1 with the SCV, still associated with SCV in wortmannin-treated cells . We have therefore concluded that a 3-phosphoinositide-dependent step exists following recruitment of Rab7 to the SCV . The data also imply that 3-phosphoinositide-dependent effectors of Rab5 are not an absolute requirement for recruitment of Rab7 . Despite failure to acquire LAMP-1, the SCV persists and allows effective replication of Salmonella within wortmannin-treated host cells . These findings imply that PI3-K is involved in the development of the SCV but is not essential for intracellular survival and proliferation of Salmonella. Diagn Microbiol Infect Dis, 2002 Jan, 42(1), 17 - 20 Susceptibility of human isolates of Salmonella typhimurium DT 104 to antimicrobial agents used in human and veterinary medicine; Beaudin BA et al.; Multiple antibiotic resistance is frequently observed among strains of Salmonella typhimurium DT104 . We examined the antibiotic resistance patterns of 240 human isolates submitted from central and northern Alberta to our laboratory for confirmatory testing during 1996-1999 . Broth microdilution MIC panels included antibiotics proposed by the Canadian National Enteric Disease Surveillance Committee for human and animal isolates . Seven different susceptibility patterns were observed . The two most common patterns accounted for 83% of isolates; 48% were susceptible to all antibiotics tested and 35% were resistant to ampicillin, tetracycline, chloramphenicol and amoxicillin-clavulanate . All strains were susceptible to enrofloxacin and trovafloxacin with variable resistance to kanamycin and chloramphenicol . There were more susceptible isolates observed in 1996 and 1997 than in 1998 and 1999, but multiple resistant isolates were found throughout the study period. Mutat Res, 2002 Feb 15, 514(1-2), 133 - 46 Effects of the formaldehyde releasing preservatives dimethylol urea and diazolidinyl urea in several short-term genotoxicity tests; Pfuhler S et al.; The two formaldehyde (FA)-releasers dimethylol urea (DMU) and diazolidinyl urea (DZU) are widely used as preservatives or additives . They were tested for genotoxicity in three short-term test systems, i.e . in the Salmonella typhimurium mutagenicity assay, in the in vitro micronucleus test with V79 Chinese hamster cells and in the in vitro tubulin assembly assay using isolated tubulin from pig brains . The polymerization products obtained in the tubulin assembly assay were examined additionally by electron microscopy.In the S . typhimurium mutagenicity assay with the pre-incubation assay both FA-releasers tested show a clear and concentration-dependent increase in the number of revertants in strains TA98, TA100 and TA102 with and without metabolic activation (rat liver S9 mix) . In all cases, a biologically relevant increase in the number of revertants was achieved within the concentration range tested (DZU: 0.04-1.8 micromol per plate, DMU: 0.21-8.33 micromol per plate) . FA was tested at 0.06-2.5 micromol per plate and lead to similar effects.Both compounds induce the formation of micronuclei (concentration range tested: DZU: 2.5-50 micromol/l, DMU: 3.3-333 micromol/l) . However, DMU shows a comparatively weaker effect exclusively in the absence of the metabolizing enzymes . By contrast, DZU yields a distinct increase of the micronucleus rate in the absence and in the presence of S9 . In addition, DZU predominantly causes an increase of large micronuclei, which suggests that this compound has a marked aneugenic potential . Cytotoxic effects accompany the clastogenic effects of both DMU and DZU.The examination of DMU and DZU in view of a possible aneugenic potential in the tubulin assembly assay yielded the following results: DMU at concentrations up to 10 mmol/l did not influence the formation of microtubuli, whereas DZU inhibited this process completely at 3 mmol/l . FA at 6 mmol/l completely inhibited the tubulin assembly . These results could clearly be confirmed by electron microscopy examination . The different potential of the two compounds with respect to the inhibition of tubulin formation is apparently due to a significant difference in the degree of FA release.According to these results, both compounds have to be considered as genotoxic in vitro . On account of these data and because of the widespread use of these two compounds in various products used in daily life, a reevaluation of the risk associated with these compounds seems to be necessary. Mutat Res, 2002 Feb 15, 514(1-2), 19 - 27 Parthenin, a sesquiterpene lactone of Parthenium hysterophorus L . is a high toxicity clastogen; Ramos A et al.; The in vitro and in vivo genotoxicity of parthenin, a sesquiterpene lactone from Parthenium hysterophorus L . with allergenic and irritant action, was assessed in three short-term tests: bacterial reversion in Salmonella typhimurium and Escherichia coli, in vitro chromosomal aberrations in peripheral blood lymphocytes and micronuclei in mouse peripheral blood . Parthenin was not mutagenic in S . typhimurium strains TA 1535, TA 1537, TA 98 and TA 100 but a weak response was observed in TA 102 (+S9) from 0.19 to 1.22 micromole per plate . Concentrations of 7.62 micromole per plate or higher were toxic, but the effect was reduced when S9 was present . Screening of oxidative mutagenesis with E . coli strains IC 188 and IC 203 gave negative results . Parthenin induced chromosomal aberrations, mainly chromatid breaks, in blood lymphocytes exposed to 10-60 microM during 20 h . An association was found with cytotoxicity, since concomitant nuclear alterations such as pycnosis, micronuclei and karyorrhexis were observed . Sister chromatid exchanges (SCEs) in lymphocytes were not influenced by exposure to parthenin; rather a decrease was observed at 60 microM . On the other hand, a minor increment in polyploid metaphases was found at 40 microM . When a single intraperitoneal (i.p.) dose of 4-31 mg/kg of parthenin was administered to mice, a positive increase in the micronucleated reticulocyte (RET) frequency was observed at 48 h for both sexes at the highest dose. FEMS Microbiol Lett, 2002 Jan 10, 206(2), 229 - 34 Salmonella typhimurium DsbA is growth-phase regulated; Goecke M et al.; Northern blot analyses, transcription assays using a dsbA::lacZ transcriptional fusion, and primer extension mapping were used to characterize the promoter region of dsbA from Salmonella typhimurium . Transcription assays measuring promoter activity of a 258-bp segment of DNA immediately upstream of the dsbA translational start site showed strong growth-phase dependence, with maximal expression in stationary phase and high levels of expression maintained for at least 72 h . This expression was not RpoS-dependent . Two transcripts initiating in the dsbA promoter region were mapped by primer extension analysis and their levels were monitored by Northern blot analysis . Growth conditions such as pH and O(2) levels affected dsbA transcription independently of growth phase . The data suggests that the promoter region of S . typhimurium is not constitutively activated . Its regulation may reflect a requirement for DsbA during conditions resulting in stationary-phase-like growth in the environment. Environ Mol Mutagen, 2002, 39(1), 43 - 8 Mutagenic activity and mutational specificity of antiprotozoal drugs with and without nitrite treatment; Ono-Ogata T et al.; We examined the mutagenic activities of six antiprotozoal drugs (three diaminopyrimidine compounds {pyrimethamine, diaveridine, and trimethoprim} and three 8-aminoquinoline derivatives {primaquine, pentaquine, and pamaquine}) in Escherichia coli WP2uvrA/pKM101 and Salmonella typhimurium TA100 and TA98 with and without nitrite treatment . The diaminopyrimidine compounds showed no mutagenic activity under any condition in any strain . The 8-aminoquinoline derivatives after nitrite treatment at 5-20 mM for 5 min at pH 3, on the contrary, showed clear mutagenicity in TA100 and WP2uvrA/pKM101 in the presence and absence of S9 mix . We concluded that 8-aminoquinoline derivatives became mutagenic following nitrite treatment . In the Lac(+) reversion assay with E . coli WP3101P-WP3106P, these nitrite-treated compounds induced G:C --> A:T transitions and G:C --> T:A transversions in the absence of S9 mix . On the other hand, A:T --> T:A transversions were induced only in the presence of S9 mix, suggesting a different kind of products may be responsible for the mutagenicity . Protein Expr Purif, 2002 Feb, 24(1), 138 - 51 Expression and purification of the rifamycin amide synthase, RifF, an enzyme homologous to the prokaryotic arylamine N-acetyltransferases; Pompeo F et al.; The assembly of the polyketide backbone of rifamycin B by the type I rifamycin polyketide synthase, encoded by the rifA-rifE genes, is terminated by the product of the rifF gene, an amide synthase that releases the completed undecaketide as its macrocyclic lactam . The sequence of the RifF protein from Amycolatopsis mediterranei shows 26% identity and 40% homology with the members of the arylamine N-acetyltransferase (NAT) family of proteins . Based on the homology of the primary structures and the similarity of the reactions catalyzed by the two enzymes, we have compared the RifF protein with members of the NAT family . We have modeled the three-dimensional (3D) structure of RifF using NAT from Salmonella typhimurium and Mycobacterium smegmatis as a template . Proteolytic digestions of RifF revealed accessible regions in the protein which are in agreement with the modeled structure . We have expressed the whole protein and individual domains of the protein based on comparison with NAT from S . typhimurium and have purified the proteins by affinity chromatography using a hexahistidine tag . RifF has been further purified using ion-exchange (Mono Q) chromatography . An antiserum has been generated using the C-terminal nona- and tridecapeptides of RifF and has been shown to recognize RifF uniquely . It does not cross-react with any other member of the NAT family . Food Addit Contam, 2002 Jan, 19(1), 62 - 9 Antimutagenic activity of natural phenolic compounds present in the common bean (Phaseolus vulgaris) against aflatoxin B1; Cardador-Martinez A et al.; Polyphenols with antimutagenic and anticarcinogenic properties are present in fruits, vegetables and legumes . In this study, the Salmonella typhimurium tester strains TA98 and TA100 were used in the microsuspension assay to examine the antimutagenic effect of phenolic compounds extracted from the common bean (Phaseolus vulgaris) against mutagenicity induced by aflatoxin B1 (AFB1) . A dose-response curve was constructed for AFB1; from which a level of 40 ng AFB1/tube was selected for all antimutagenicity assays . The AFB1 and phenolic extract (PE) were not toxic to the bacteria at concentrations tested . In the case of PE, results were similar to the number of spontaneous revertants for TA98 and TA100 . The inhibitory effect of PE against AFB1 mutagenicity was dose-dependent at the lower concentrations tested (2.5, 5, 10, 12.5, 15 and 25 microgram-equivalent (+)-catechin/tube for TA98; 0.5, 1, 1.5, 2.5, 5, 10 and 25 microgram-equivalent (+)-catechin/ tube for TA100) . Further, a two-stage incubation procedure was used to investigate the potential interaction between PE and AFB1 . The greatest inhibitory effect of the PE on AFB1 mutagenicity occurred when PE and AFB1 were incubated together . When the bacteria were first incubated with PE followed by a second incubation with AFB1, lower inhibition was observed . Lower inhibition was also observed when the bacteria were first incubated with AFB1 followed by a second incubation with PE . The results suggest that the mechanism of inhibition could involve the formation of a chemical complex between of PE and AFB1. J Infect Chemother, 1999 Dec, 5(4), 196 - 200 Diffusion of macrolide antibiotics through the outer membrane of Moraxella catarrhalis; Tsujimoto H et al.; We reported previously that the high susceptibility of Moraxella catarrhalis to macrolide antibiotics and other hydrophobic antimicrobial agents was related to the hydrophobicity of the cell surface . Electrophoretic analysis of lipopolysaccharide (LPS) extracted from M . catarrhalis revealed a deep rough-type profile similar to that of an LPS Re type mutant of Salmonella typhimurium, which also exhibits high susceptibility to macrolides . Moreover, treatment of 32P-labeled cells of M . catarrhalis by phospholipase C induced the release of radioactive materials . These results suggested that hydrophobic agents such as macrolides readily access the cell surface exposed by the deep rough-type LPS and phospholipids, and permeate into the cell interior through the lipid bilayer . In fact, M . catarrhalis cells rapidly accumulated large amounts of the macrolide antibiotics, erythromycin and rokitamycin, whereas no accumulation of the macrolides was observed in cells having smooth-type or Rc type LPS under the same conditions. J Food Prot, 2002 Jan, 65(1), 196 - 8 Growth of Escherichia coli O157:H7, Salmonella typhimurium DT104, and Listeria monocytogenes in dark cutting beef at 10 or 22 degrees C; Hooper-Kinder CA et al.; An experiment was conducted to determine the effects of the dark, firm, and dry (DFD) condition of beef on growth of the foodborne pathogens Escherichia coli O157:H7, Salmonella Typhimurium DT104, and Listeria monocytogenes Scott A in ground beef . Longissimus muscles from a DFD carcass (pH = 6.45) and normal carcass (N; pH = 5.64) were ground and samples obtained (100 and 0% DFD, respectively) . Equal amounts of the 0 and 100% DFD ground samples were mixed to obtain 50% DFD samples . Inoculated 0, 50, and 100% DFD samples were packaged into oxygen-permeable overwrap and stored at 10 degrees C for E . coli O157:H7, Salmonella Typhimurium DT104, and L . monocytogenes Scott A or at 22 degrees C for E . coli O157:H7 . Growth characteristics of E . coli O157:H7, Salmonella Typhimurium DT104, and L . monocytogenes Scott A did not differ (P > 0.05) between 0 and 100% DFD . Results indicated that the DFD beef used in this study was no more susceptible to growth of E . coli O157:H7, Salmonella Typhimurium, or L . monocytogenes Scott A than N beef. J Appl Toxicol, 2002 Jan-Feb, 22(1), 45 - 60 Genetic toxicology studies with glutaraldehyde; Vergnes JS et al.; Glutaraldehyde (GA; CAS no . 111-30-8) has a wide spectrum of industrial, scientific and biomedical applications, with a potential for human exposure particularly in its biocidal applications . The likelihood for genotoxic effects was investigated in vitro and in vivo . A Salmonella typhimurium reverse mutation assay showed no evidence for mutagenic activity with strains TA98, TA1535, TA1537 and TA1538, with or without metabolic activation . However, there was a weak mutagenic response (1.9-2.3-fold at the highest non-toxic concentration) with TA100 in the presence of metabolic activation . In a Chinese hamster ovary (CHO) forward gene mutation assay (HGPRT locus) there were no consistent, statistically significant, reproducible or dosage-related increases in the frequency of 6-thioguanine resistant cells . There were no reproducible or dosage-related increases in sister chromatid exchanges in an in vitro test in CHO cells . An in vitro cytogenetics study in CHO cells showed no evidence for an increase in chromosomal aberrations on treatment with GA, either in the presence or absence of metabolic activation . In vivo, a mouse peripheral blood micronucleus test showed no increase in micronucleated polychromatophils at sampling times of 30, 48 and 72 h after acute gavage dosing with GA at 40, 80 and 125 mg kg(-1) (corresponding to 25, 50 and 85% of the LD(50)) . The absence of an in vivo clastogenic potential was confirmed by no increase in chromosomal aberrations in a rat bone marrow cytogenetics study with sampling at 12, 24 and 48 h after acute gavage dosing with GA (12.5, 30 or 60 mg kg(-1) with males, and 7.5, 20 or 40 mg kg(-1) with females) . Thus, in this series of tests, GA produced genotoxic effects in vitro only in a bacterial reverse mutation assay with no evidence for in vivo genotoxicity . Genome Biol . 2002;3(1):RESEARCH0004 . Epub 2001 Dec 14. Significance of two distinct types of tryptophan synthase beta chain in Bacteria, Archaea and higher plants; Xie G et al.; BACKGROUND: Tryptophan synthase consists of two subunits, alpha and beta . Two distinct subgroups of beta chain exist . The major group (TrpEb_1) includes the well-studied beta chain of Salmonella typhimurium . The minor group of beta chain (TrpEb_2) is most frequently found in the Archaea . Most of the amino-acid residues important for catalysis are highly conserved between both TrpE subfamilies . RESULTS: Conserved amino-acid residues of TrpEb_1 that make allosteric contact with the TrpEa subunit (the alpha chain) are absent in TrpEb_2 . Representatives of Archaea, Bacteria and higher plants all exist that possess both TrpEb_1 and TrpEb_2 . In those prokaryotes where two trpEb genes coexist, one is usually trpEb_1 and is adjacent to trpEa, whereas the second is trpEb_2 and is usually unlinked with other tryptophan-pathway genes . CONCLUSIONS: TrpEb_1 is nearly always partnered with TrpEa in the tryptophan synthase reaction . However, by default at least six lineages of the Archaea are likely to use TrpEb_2 as the functional beta chain, as TrpEb_1 is absent . The six lineages show a distinctive divergence within the overall TrpEa phylogenetic tree, consistent with the lack of selection for amino-acid residues in TrpEa that are otherwise conserved for interfacing with TrpEb_1 . We suggest that the standalone function of TrpEb_2 might be to catalyze the serine deaminase reaction, an established catalytic capability of tryptophan synthase beta chains . A coincident finding of interest is that the Archaea seem to use the citramalate pathway, rather than threonine deaminase (IlvA), to initiate the pathway of isoleucine biosynthesis. Ter Arkh, 2001, 73(11), 70 - 3 {Priming-phenomenon of neutrophils in patients with Flexner infection}; Gorobchenko AN et al.; AIM: To study reproducibility of priming phenomenon of neutrophils in patients with acute Flexner's dysentery and its realization manifestation . MATERIAL AND METHODS: A chemiluminescent response of peripheral blood neutrophils was studied in patients with acute mild and moderate dysentery in the presence of luminol . Lipopolysaccharide Salmonella typhimurium at a final concentration of 20 ng/ml served as a priming substance of S-chemotype . Neutrophils were stimulated with phorbol myristate acetate in concentration 10(-6) M and isolated on Histopaque double gradient (Sigma reagents, USA) . RESULTS: In reproduction of priming-phenomenon in vitro on neutrophils of patients with acute Flexner's dysentery chemiluminescence amplitude increased 1.29-1.69-fold vs control . CONCLUSION: Priming-phenomenon on neutrophils in acute dysentery is reproducible . This confirms modulating properties of lipopolysaccharides in conditions of systemic nonphysiological endotoxinemia . Priming phenomenon may be involved in both maintenance of homeostasis and pathophysiological processes. J Agric Food Chem, 2002 Jan 30, 50(3), 633 - 41 Decontamination of aflatoxin-forming fungus and elimination of aflatoxin mutagenicity with electrolyzed NaCl anode solution; Suzuki T et al.; Electrolysis of a 0.1% (17.1 mM) solution of NaCl using separate anode and cathode compartments gives rise to solutions containing active chemical species . The strongly acidic "anode solution" (EW+) has high levels of dissolved oxygen and available chlorine in a form of hypochlorous acid (HOCl) with a strong potential for sterilization, which we have investigated here . Exposing Aspergillus parasiticus at an initial density of 10(3)spores in 10 microL to a 50-fold volume (500 microL) of EW+ containing ca . 390 micromol HOCl for 15 min at room temperature resulted in a complete inhibition of fungal growth, whereas the cathode solution (EW-) had negligible inhibitory effects . Moreover, the mutagenicity of aflatoxin B(1) (AFB(1)) for Salmonella typhimurium TA-98 and TA-100 strains was strongly reduced after AFB(1) exposure to the EW+ but not with the EW- . In high-performance liquid chromatography analysis, the peak corresponding to AFB(1) disappeared after treatment with the EW+, indicating decomposition of the aflatoxin . In contrast, the routinely used disinfectant sodium hypochlorite, NaOCl, of the same available chlorine content as that of EW+ but in a different chemical form, hypochlorite (OCl-) ion, did not decompose AFB(1) at pH 11 . However, NaOCl did decompose AFB(1) at pH 3, which indicated that the principle chemical formula to participate in the decomposition of AFB(1) is not the OCl- ion but HOCl . Furthermore, because the decomposition of AFB(1) was suppressed by pretreating the EW+ with the OH radical scavenger thiourea, the chemical species responsible for the AFB(1)-decomposing property of the EW+ should be at least due to the OH radical originated from HOCl . The OH in EW+ was proved by electron spin resonance analysis. Toxic Rep Ser, 2000 May, (47), 1 - 56, A1-E6 NTP technical report on the toxicity studies of methacrylonitrile (CAS No . 126-98-7) . Administered by gavage to F344/N rats and B6C3F1 mice; Ghanayem BI; Methacrylonitrile is an aliphatic nitrile used extensively in the preparation of homo- and copolymers, elastomers, and plastics and as a chemical intermediate in the preparation of acids, amides, esters, and other nitriles . This aliphatic nitrile is also used as a replacement for acrylonitrile in the manufacture of an acrylonitrile/butadiene/styrene-like polymer . Methacrylonitrile was nominated for toxicity and carcinogenicity testing by the National Cancer Institute due to its high production volume and extensive use, the lack of chronic or carcinogenicity data, and its structural resemblance to the known rat carcinogen acrylonitrile . The current 13-week studies were conducted as part of an overall effort by the NTP to assess the toxicity and carcinogenicity of methacrylonitrile . During the 13-week studies, groups of 20 male and 20 female F344/N rats were administered 0, 7.5, 15, 30, 60, or 120 mg methacrylonitrile/kg body weight in deionized, purified water by gavage . Groups of 20 male and 20 female B6C3F1 mice were administered 0, 0.75, 1.5, 3, 6, or 12 mg/kg methacrylonitrile . Ten male and ten female rats and mice from each group were evaluated on day 32 . The results of these studies clearly revealed that male rats are more sensitive than females to methacrylonitrile treatment . In the rat study, 19 males and one female administered 120 mg/kg and two males administered 60 mg/kg died during the first week of the study . Males in the 60 mg/kg group at the 32-day interim evaluation and at 13 weeks and females in the 120 mg/kg group at 13 weeks had significantly lower final mean body weights and body weight gains than did the vehicle controls; the surviving male in the 120 mg/kg group also weighed less than the controls at the 32-day interim evaluation . Clinical findings of toxicity were dose dependent and included lethargy, lacrimation, tremors, convulsions, ataxia, and abnormal breathing . There was hematologic evidence indicating that administration of methacrylonitrile induced minimal, normocytic, normochromic anemia . At the 32-day interim evaluation, a minimal dose-related anemia was evidenced by decreases in hematocrit values, hemoglobin concentrations, and erythrocyte counts in male and female rats . The anemia ameliorated by week 13 . Administration of methacrylonitrile resulted in dose-related increases in serum thiocyanate and blood cyanide concentrations of male and female rats . These changes were expected and would be consistent with the in vivo metabolism of methacrylonitrile to cyanide . Blood cyanide concentrations were generally higher in males than in females, which may explain the higher sensitivity of males to the lethal effect of methacrylonitrile . There was also biochemical evidence of increased hepatocellular leakage and/or altered function in dosed male rats, suggesting that the liver may be a target organ for toxic effects of methacrylonitrile . Minimal, but significant, decreases in absolute right kidney and thymus weights (32-day interim evaluation) and increases in liver and stomach weights (week 13) occurred in male rats that received 60 mg/kg compared to the vehicle controls . In female rats, stomach weights of the 60 and 120 mg/kg groups were significantly greater and thymus weights of the 120 mg/kg group were significantly less than those of the controls on day 32 and at week 13; liver weights were also significantly greater in females in the 120 mg/kg group than in the vehicle controls on day 32 . Male and female rats administered 60 mg/kg and females administered 120 mg/kg had significantly greater incidences of metaplasia of the nasal olfactory epithelium on day 32 and at the end of the study than did the vehicle controls; incidences of olfactory epithelial necrosis were also significantly greater in females in the 60 and 120 mg/kg groups than in the vehicle controls on day 32 . Incidence and/or severity increased with increasing dose in females; however, the mortality in male rats administered 120 mg/kg made it difficult to assess the dose-response relationship in males . The no-observed-adverse-effect level for the nasal cavity of rats was 30 mg/kg . Female rats administered 60 or 120 mg/kg methacrylonitrile had significantly longer estrous cycles than did the vehicle controls . Females in the 60 mg/kg group spent more time in diestrus than the vehicle controls . One male and one female mouse in the 12 mg/kg groups died early . Methacrylonitrile administration caused no significant differences in final mean body weights or body weight gains . Clinical findings included lethargy, tremors, ataxia, convulsions, and abnormal breathing . At the 32-day interim evaluation, stomach weights of males administered 3 mg/kg or greater were significantly greater and thymus weights of males in the 12 mg/kg group were significantly less than those of the vehicle controls . At week 13, however, the stomach weights of only males in the 12 mg/kg group were increased relative to the vehicle controls . No treatment-related histopathologic lesions occurred in mice . Methacrylonitrile did not induce mutations in any of several strains of Salmonella typhimurium, with or without S9 activation, and did not induce sex-linked recessive lethal mutations in germ cells of male Drosophila melanogaster fed methacrylonitrile during the larval stage . Results of in vivo bone marrow micronucleus tests with methacrylonitrile in male rats and mice were also negative . In summary, gavage administration of methacrylonitrile to rats and mice resulted in dose-dependent lethargy, tremors, lacrimation, convulsions, and abnormal breathing . However, these effects were more pronounced in rats than mice; these differences may be attributed to the higher doses of methacrylonitrile administered to rats . Body weight gain and survival data of rats demonstrated that males are more sensitive to methacrylonitrile dosing than females . There is an apparent correlation between blood cyanide concentrations and survival rates, with males having greater cyanide concentrations and lower survival rates than female rats administered methacrylonitrile . Microscopically, the only target of methacrylonitrile toxicity was the olfactory epithelium of the nasal cavity . Necrotic and metaplastic effects were induced in male and female rats that received 60 or 120 mg/kg per day . No similar lesions were observed in mice administered methacrylonitrile . The no-observed-adverse-effect level for olfactory epithelial lesions in male and female rats administered methacrylonitrile for 13 weeks was 30 mg/kg per day . No clear chemical-related effects were observed in male or female mice administered methacrylonitrile for 13 weeks by gavage at doses up to 12 mg/kg per day. Toxic Rep Ser, 1996 Mar, (52), 1 - 91, A1-9, B1-9 passim NTP technical report on toxicity studies of urethane in drinking water and urethane in 5% ethanol administered to F344/N rats and B6C3F1 mice; Chan PC; Urethane, a byproduct of fermentation found in alcoholic beverages, is carcinogenic in rodents and is classified by the International Agency for Research on Cancer as a possible human carcinogen . The United States Food and Drug Administration nominated urethane for study because of the widespread exposure of humans through the consumption of fermented foods and beverages and because of a lack of adequate dose-response data about the carcinogenicity of urethane with and without the coadministration of ethanol . Comparative studies of urethane in drinking water and in 5% ethanol were conducted to investigate possible effects of ethanol on urethane toxicity . Toxicokinetic studies of urethane in drinking water and in 5% ethanol and genetic toxicity studies of urethane in vivo and in vitro were also conducted . Groups of 10 male and 10 female F344/N rats and B6C3F1 mice, 6 weeks of age, received 0, 110, 330, 1,100, 3,300, or 10,000 ppm urethane in drinking water or in 5% ethanol for 13 weeks . Toxicokinetic evaluations were performed for urethane in the plasma of male mice after 13 weeks of administration in drinking water or 5% ethanol . The mutagenicity of urethane in Salmonella typhimurium strains TA97, TA98, TA100, TA1535, and TA1537 with and without S9 was tested at doses up to 16,666 micrograms/plate; urethane was also tested for induction of sister chromatid exchanges and chromosomal aberrations in cultured Chinese hamster ovary cells and sex-linked recessive lethal mutations and chromosomal reciprocal translocations in Drosophila melanogaster . The frequency of micronucleated erythrocytes induced in peripheral blood and bone marrow cells of mice by urethane in drinking water and in 5% ethanol was also evaluated . In rats that received urethane in drinking water, seven males and four females administered 10,000 ppm and one female administered 3,300 ppm died before the end of the study; body weight gains were reduced at these concentrations . Two males and all females given 10,000 ppm urethane in 5% ethanol died during the study, and the body weight gains of males and females that received 3,300 ppm were lower than those of the controls . Relative right kidney, liver, and lung weights of males and females and relative right testis weights of males administered 1,100 ppm or greater were generally higher than those of the controls in each study . Leukopenia and lymphopenia were observed in rats receiving urethane in either drinking water or ethanol and occurred in males receiving 330 ppm or greater and females receiving 110 ppm or greater . Other differences in hematology and clinical chemistry variables were not considered to be biologically significant . Lymphoid depletion of the spleen, lymph nodes, and thymus was observed in male and female rats receiving 1,100, 3,300, or 10,000 ppm urethane in drinking water . Cellular depletion of the bone marrow occurred in males and females in the 10,000 ppm groups . Hepatocellular fatty changes and clear cell foci of alteration were noted in the liver of males and females that received 3,300 or 10,000 ppm . The incidences of nephropathy were significantly increased in female rats that received 1,100 ppm or greater; the severity of this lesion in exposed males and females was greater than that in the controls . Females that received 330 ppm or greater had higher incidences of cardiomyopathy than the controls; the severity of this lesion was greater in males in the 10,000 ppm group and females in the 3,300 and 10,000 ppm groups than in the controls . In rats that received urethane in 5% ethanol, lymphoid depletion occurred in males and females in the 3,300 and 10,000 ppm groups . Cellular depletion of the bone marrow was observed in males and females in the 10,000 ppm groups . Only males in the 10,000 ppm group had hepatocellular fatty change (8/10) and clear cell foci (1/10); the incidence and severity of nephropathy in males and females and cardiomyopathy in males were similar to those in rats administered urethane in drinking water; however, no cardiomyopathy was observed in females receiving urethane in ethanol . The estrous cycle length of females receiving urethane in ethanol appeared to be longer than that of females receiving urethane in drinking water . Because cycle length was longer in the 10,000 ppm groups than in the controls in both the drinking water and ethanol vehicle studies, this difference may represent an exacerbation of the toxicity of urethane . A longer estrous cycle may be a sign of reproductive impairment and correlates with a decrease in female fecundity . All mice administered 10,000 ppm urethane in either vehicle died . All mice that received 3,300 ppm urethane in drinking water died, while only one male and four females receiving 3,300 ppm urethane in 5% ethanol died . Body weight gains of males and females in all 1,100 ppm groups were less than those of the respective controls, but the weight gains of mice receiving 1,100 ppm urethane in 5% ethanol were greater than those of mice receiving urethane in drinking water . The mean body weights of the lower exposure groups were similar to those of the respective controls, and there were no other differences between the body weights of mice receiving urethane in drinking water and those receiving urethane in 5% ethanol . Fluid consumption, and therefore total urethane intake, appeared lower in mice receiving the 5% ethanol vehicle than in those receiving the water vehicle . The relative right kidney, liver, and lung weights of males and females administered urethane in drinking water or ethanol were generally greater than those of the controls . Clearance of urethane from the plasma of male mice was complete within 2 hours after urethane was administered in water, but urethane was not cleared 12 hours after administration in 5% ethanol . At the end of 13 weeks of urethane administration, the plasma urethane elimination half-life was 0.8 hours; the kinetics were similar for concentrations of 110, 330, and 1,100 ppm urethane in water and in ethanol . However, at each exposure level, the plasma urethane concentration was four times greater for urethane administered in 5% ethanol than for urethane administered in drinking water, indicating a possible inhibition of urethane metabolism by ethanol . Kinetic measurements for elimination by female mice could not be obtained from the data collected . In mice administered urethane in drinking water, lung inflammation occurred in males and females that received 1,100 ppm or greater . Alveolar epithelial hyperplasia occurred in the lungs of males in the 330 and 1,100 ppm groups and females in the 1,100 ppm group; one male mouse in the 330 ppm group had an alveolar/bronchiolar adenoma (see the following summary table) . Mice receiving urethane in 5% ethanol had lower incidences and severity of lung inflammation but generally greater incidences and severity of alveolar epithelial hyperplasia than mice receiving the same concentrations of urethane in drinking water . Alveolar/bronchiolar adenomas occurred in four males and one female administered urethane in ethanol . {table: see text} Nephropathy was observed in males and females that received urethane in either vehicle, and the lesions in female mice were more severe than those in male mice; ethanol did not appear to increase the incidence or severity of nephropathy . Cardiomyopathy occurred in males and females that received 1,100 or 3,300 ppm urethane in drinking water and in females that received 3,300 ppm urethane in ethanol . Lymphoid depletion occurred in mice that received 3,300 or 10,000 ppm urethane; 5% ethanol did not appear to enhance these effects . However, urethane in 5% ethanol induced ovarian atrophy; the incidence of this lesion was lower in females receiving urethane in drinking water . A concentration of 1,100 ppm urethane in either drinking water or ethanol effectively stopped estrous cycling . Urethane is clearly genotoxic in vitro and in vivo . In vitro, urethane induced mutations in Salmonella typhimurium strain TA1535 in the presence of liver S9 enzymes . Sister chromatid exchanges were induced in cultured Chinese hamster ovary (CHO) cells with and without S9 . However, no induction of chromosomal aberrations was observed in CHO cells treated with urethane, with or without S9 . In vivo, urethane induced sex-linked recessive lethal mutations and reciprocal translocations in germ cells of adult male Drosophila melanogaster fed urethane . Significantly increased frequencies of micronucleated erythrocytes were observed in peripheral blood obtained from male and female mice after 45 days of exposure and in bone marrow and peripheral blood obtained after 13 weeks of exposure to urethane in drinking water . There appeared to be no significant difference in the magnitude of the response in the peripheral blood micronucleus test between mice administered urethane in drinking water and mice administered urethane in 5% ethanol . In summary, concentrations of 1,100 ppm urethane or greater in drinking water caused lymphoid and bone marrow cell depletion and hepatocellular lesions and increased the severity of nephropathy and cardiomyopathy in male and female rats . The lethal effects of 10,000 ppm urethane were slightly exacerbated by 5% ethanol in female rats . Urethane administered in drinking water induced lung inflammation, alveolar and bronchiolar hyperplasia, alveolar/bronchiolar adenomas, nephropathy, cardiomyopathy, lymphoid and bone marrow cell depletion, seminiferous tubule degeneration, and ovarian atrophy and follicular degeneration in mice . In female mice, 5% ethanol appeared to exacerbate ovarian atrophy . Mice administered urethane in 5% ethanol consumed less fluid, and therefore less urethane, than mice receiving urethane in drinking water . Coadministration of urethane and ethanol inhibited the clearance of urethane from plasma . (ABSTRACT TRUNCATED) Natl Toxicol Program Tech Rep Ser, 2001 Nov, (497), 1 - 225 Toxicology and carcinogenesis studies of methacrylonitrile (CAS No . 126-98-7) in F344/N rats and B6C3F1 mice (gavage studies); NTP technical report on the toxicity and metabolism studies of chloral hydrate (CAS No . 302-17-0) . Administered by gavage to F344/N rats and B6C3F1 mice; Chloral hydrate is widely used as a sedative and a hypnotic in pediatric medicine . It is also a byproduct of water chlorination . Chloral hydrate has been shown to be genotoxic in numerous prokaryotic and eukaryotic assay systems including human lymphocytes in vitro . One of its metabolites, trichloroacetic acid, has demonstrated hepatocarcinogenic activity in mice . Trichloroethylene and perchloroethylene, both of which are metabolized to chloral hydrate, have been shown to be carcinogenic in rats and/or mice . Because of this evidence of carcinogenicity and because of the wide-spread use of chloral hydrate, 16- or 17-day range-finding toxicity studies and separate 16- or 17-day metabolism studies were performed in F344/N rats and B6C3F1 mice in preparation for further long-term rodent studies . In addition, in vitro studies of the metabolism and DNA-binding capacity of chloral hydrate and its metabolites were performed . Genetic toxicity studies were conducted in Salmonella typhimurium, cultured Chinese hamster ovary cells, Drosophila melanogaster, and mouse bone marrow cells . For the range-finding studies, groups of eight male and eight female F344/N Nctr BR rats and B6C3F1/Nctr BR (C57BL/6N x C3H/HeN MTV-) mice were administered 0, 50, 100, 200, 400, or 800 mg chloral hydrate per kg body weight in water by gavage 5 days per week for 17 days (rats) or 16 days (mice) for a total of 12 doses . One male rat receiving 800 mg/kg died after five doses . Two 800 mg/kg female rats died after dosing ended but before study termination . One male mouse in each group except the 400 mg/kg group died before the end of the study . Two 800 mg/kg female mice also died before the end of the study . The final mean body weight of 800 mg/kg male rats and the mean body weight gains of 400 and 800 mg/kg males were significantly less than those of the vehicle controls . The mean body weight gains of all groups of dosed male mice were significantly greater than that of the vehicle control group . The only clinical finding in rats and mice attributed to chloral hydrate treatment was light sedation in the 400 mg/kg groups and heavy sedation in the 800 mg/kg groups; sedation subsided within 30 minutes or 3 hours, respectively . The liver weights of 400 mg/kg male mice and 800 mg/kg male and female mice were significantly greater than those of the vehicle control groups . No chemical-related lesions were observed in rats or mice . Male and female rats and mice were administered a single dose of 50 or 200 mg chloral hydrate per kg body weight in water by gavage, or 12 doses of 50 or 200 mg/kg over 17 days (rats) or 16 days (mice) . Plasma concentrations of chloral hydrate and its metabolites were determined 15 minutes, 1, 3, 6, and 24 hours, and 2, 4, 8, and 16 days after receiving 1 or 12 doses . Maximum concentrations of chloral hydrate were observed at the initial sampling point of 15 minutes . By 1 hour, the concentrations had dropped substantially, and by 3 hours, chloral hydrate could not be detected in rats or mice . Trichloroacetic acid was the major metabolite detected in the plasma . In rats, the concentrations rose slowly, with the peaks occurring between 1 and 6 hours after treatment . In mice, the peak concentrations were found 1 hour after dosing . The concentrations then slowly decreased such that by 2 days the metabolite could no longer be detected in rats or mice . Trichloroethanol was assayed both as the free alcohol and its glucuronide . In rats, the maximum concentrations of free trichloroethanol occurred at 15 minutes, while the peak concentrations of trichloroethanol glucuronide were found at 1 hour; by 3 hours, concentrations of both metabolites approached background levels . In mice, the maximum concentrations of both metabolites occurred at 15 minutes, and by 1 to 3 hours concentrations approached background levels . The plasma concentrations of chloral hydrate and its metabolites were dose dependent in rats and mice . In mice, plasma concentrations of trichloroacetic acid were significantly higher after a single dose than after 12 doses . None of the metabolic parameters appears to account for species differences that may exist in hepatocarcinogenicity . The data from the study of metabolism and DNA adduct formation indicated that in vitro metabolism of 200 microM to 5 mM chloral hydrate by male B6C3F1 mouse liver microsomes (control microsomes) generated free radical intermediates that resulted in endogenous lipid peroxidation, forming malondialdehyde, formaldehyde, acetaldehyde, acetone, and propionaldehyde . Similar concentrations of trichloroacetic acid and trichloroethanol, the primary metabolites of chloral hydrate, also generated free radicals and induced lipid peroxidation . Lipid peroxidation induced by trichloroacetic acid nearly equaled that induced by chloral hydrate, while that from trichloroethanol was three- to fourfold less . Metabolism of 200 microM to 5 mM chloral hydrate, trichloroacetic acid, and trichloroethanol by liver microsomes of B6C3F1 mice pretreated with pyrazole (pyrazole-induced microsomes) yielded lipid peroxidation products at concentrations two- to threefold greater than those from liver microsomes of untreated mice . Additionally, chloral hydrate-induced lipid peroxidation catalyzed by control and pyrazole-induced microsomes was reduced significantly by 2,4-dichloro-6-phenylphenoxyethylamine, a general cytochrome P450 inhibitor . Human lymphoblastoid transgenic cells expressing cytochrome P(450)2E1 metabolized 200 to 5,000 micrograms/mL chloral hydrate to reactants inducing mutations, whereas the parental cell line was inactive . The malondialdehyde-modified DNA adduct, 3-(2-deoxy-beta-D-erythro-pentofuranosyl)pyrimido{1,2 alpha}purin-10(3H)-one (MDA-MG-1), formed from the metabolism of 1 mM chloral hydrate, trichloroacetic acid, and trichloroethanol by control B6C3F1 mouse liver microsomes, mouse pyrazole-induced microsomes, male F344/N rat liver microsomes, and human liver microsomes in the presence and absence of calf thymus DNA was also determined . When incubated in the absence of calf thymus DNA, the amount of malondialdehyde formed from metabolism by pyrazole-induced mouse microsomes was twice that from rat or human liver microsomes . Amounts of chloral hydrate-induced and trichloroacetic acid-induced lipid peroxidation products formed from metabolism by rat and human liver microsomes were similar, and these quantities were about twice those formed from the metabolism of trichloroethanol . The quantity of MDA-MG-1 formed from the metabolism of chloral hydrate, trichloroacetic acid, and trichloroethanol by mouse, rat, and human liver microsomes exhibited a linear correlation with the quantity of malondialdehyde formed under incubation conditions in the absence of calf thymus DNA . Chloral hydrate was shown to be mutagenic in vitro and in vivo . At doses from 1,000 to 10,000 micrograms/plate, it induced mutations in S . typhimurium strain TA100, with and without S9 activation; an equivocal response was obtained in S . typhimurium strain TA98 in the absence of S9, and no mutagenicity was detected with strain TA1535 or TA1537 . Chloral hydrate at doses from 1,700 to 5,000 micrograms/mL induced sister chromatid exchanges; at doses from 1,000 to 3,000 micrograms/mL, chromosomal aberrations were induced in cultured Chinese hamster ovary cells, with and without S9 . Results of a sex-linked recessive lethal test in D . melanogaster were unclear; administration of chloral hydrate by feeding produced an inconclusive increase in recessive lethal mutations, results of the injection experiment were negative . An in vivo mouse bone marrow micronucleus test with chloral hydrate at doses from 125 to 500 mg/kg gave a positive dose trend . In summary, due to the absence of chloral hydrate-induced histopathologic lesions in rats and mice, no-observed-adverse-effect levels (NOAELs) were based on body weights of rats and liver weights of mice . The NOAELs for rats and mice were 200 mg/kg . Chloral hydrate was rapidly metabolized by rats and mice, with trichloroacetic acid occurring as the major metabolite . Peak concentrations of trichloroacetic acid occurred more quickly in mice . Plasma concentrations of chloral hydrate were dose dependent, but metabolic rates were unaffected by dose or sex . Chloral hydrate was mutagenic in vitro and in vivo . Metabolism of chloral hydrate and its metabolites produced free radicals that resulted in lipid peroxidation in liver microsomes of mice, rats, and humans . Induction of cytochrome P(450)2E1 by pyrazole increased the concentrations of lipid peroxidation products; inhibition of cytochrome P(450)2E1 by 2,4-dinitrophenylhydrazine reduced these concentrations . Metabolism of chloral hydrate and its metabolites by mouse, rat, and human liver microsomes formed malondialdehyde, and in the presence of calf thymus DNA formed the DNA adduct MDA-MG-1. Toxic Rep Ser, 2000 Apr, (61), 1 - 53, A1-13 NTP technical report on the toxicity studies of benzophenone (CAS No . 119-61-9) . Administered in feed to F344/N rats and B6C3F mice; Chhabra RS; Benzophenone is used as a photoinitiator, a fragrance enhancer, an ultraviolet curing agent, and, occasionally, as a flavor ingredient; it is also used in the manufacture of insecticides, agricultural chemicals, and pharmaceuticals and is an additive for plastics, coatings, and adhesives . In 14-week studies conducted to determine the toxicity of benzophenone, groups of 10 male and 10 female F344/N rats and B6C3F1 mice were given 0, 1,250, 2,500, 5,000, 10,000, or 20,000 ppm benzophenone in feed . These exposure concentrations resulted in the following average daily doses: 75, 150, 300, 700, or 850 mg benzophenone per kilogram body weight for male rats; 80, 160, 300, 700, or 1,000 mg/kg for female rats; 200, 400, 800, 1,600, or 3,300 mg/kg for male mice; and 270, 540, 1,000, 1,900, or 4,200 mg/kg for female mice . Animals were evaluated for clinical pathology, reproductive system effects, liver cytochrome P450 effects, and histopathology . Genetic toxicity studies were conducted in Salmonella typhimurium and mouse bone marrow polychromatic erythrocytes . Benzophenone was unpalatable at 20,000 ppm . All 20,000 ppm rats had significant body weight loss and were terminated for humane reasons before the end of studies . All male mice and four female mice in the 20,000 ppm group died . There was no exposure-related mortality in the remaining groups . Significantly decreased body weights relative to the controls were observed in all exposed groups of female rats and all exposed groups of male rats except the 1,250 ppm group . Lower body weights were apparent in 10,000 ppm male mice and in 5,000 ppm or greater female mice . In rats, the liver and kidney were identified as target organs of benzophenone toxicity . Treatment-related increases in liver weights were attributed to hypertrophy and/or cytoplasmic vacuolization of hepatocytes . Increased kidney weights were associated with a spectrum of renal changes in exposed males and females . Unique lesions observed in animals that died early as well as in survivors were well demarcated, wedge-shaped areas of prominent tubule dilatation . The lesion occurred in 2,500 ppm or greater males and in 10,000 and 20,000 ppm females . Foci of tubule regeneration were increased relative to the controls in exposed males and females . In exposed mice, significant microscopic findings were limited to centrilobular hypertrophy in the liver that corresponded to increased liver weights . The severity of hepatocyte hypertrophy was exposure-concentration dependent, with marked severity in all 20,000 ppm animals . Clinical chemistry analyses confirmed liver toxicity . In rats, increases in serum bile salt concentrations indicated cholestatic liver disease . On day 22, a 15-fold increase was evident in the 20,000 ppm groups, and at week 14, a twofold increase was seen in the 10,000 ppm groups . Increases in alanine aminotransferase and sorbitol dehydrogenase activities were mild in mice; however, more convincing of liver damage were increased alkaline phosphatase activities and serum bile salt concentrations, especially in 20,000 ppm females . Biochemical data indicated that benzophenone was a relatively potent inducer of the phenobarbital-type (2B) cytochrome P450 enzymes . Overall, induction was greater in rats than in mice . The gross (increased organ weights) and microscopic (hepatocellular hypertrophy) liver changes associated with benzophenone administration in rats and mice accompanied benzophenone-induced increases in pentoxyresorufin dealkylase activity . Benzophenone was not mutagenic in S . typhimurium strain TA98, TA100, TA1535, or TA1537, with or without S9 activation, and it did not induce micronuclei in bone marrow erythrocytes of male mice administered benzophenone by intraperitoneal injection . In conclusion, the liver is the primary target organ of benzophenone toxicity in rats and mice based on increases in liver weights, hepatocellular hypertrophy, clinical chemistry changes, and induction of liver microsomal cytochrome P450 2B isomer . The kidney was also identified as a target organ of benzophenone toxicity in rats only, based on exposure concentration-related increases in kidney weights and microscopic changes . The no-observed-adverse-effect level for benzophenone was not achieved in these studies. Bull Group Int Rech Sci Stomatol Odontol, 2000 Jan-Apr, 42(1), 23 - 9 Mouthrinses: a comparative microbiological study; Gautier G et al.; This study was performed in order to evaluate the efficacy of different mouthrinses whose use is extended in Spain . Six different antiseptic mouthrinses were studied by means of determination of Minimal Inhibitory Concentration (MIC) values against Klebsiella pneumoniae, Serratia marcescens, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella typhimurium, Bacillus subtilis, Streptococcus mutans, Prevotella intermedia, Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans . Also in vivo experiments were carried out in volunteers by the use of mouthrinses and evaluation of bacterial populations before and after the treatment . Finally, the kinetics of bacterial death was determined . Results suggested that the determination of MIC values is not a reliable method to evaluate the antibacterial effect of such products . On the other hand those rinsing solutions based on the effect of oxygen, such as those containing carbamide peroxide have a greater efficacy against anaerobic bacteria compared with rinses whose active molecule is a disinfectant . Finally, the kinetics of bacterial death demonstrates that the essential oil rinse kills bacteria much faster . All tested mouthrinses were active as antibacterial although those based on oxygen production or essential oils were more active than solutions based on chlorhexidine and Triclosan. J Biol Chem, 2002 Apr 5, 277(14), 12175 - 81 Epub 2002 Jan 17. The COOH terminus of arylamine N-acetyltransferase from Salmonella typhimurium controls enzymic activity; Mushtaq A et al.; Arylamine N-acetyltransferases (NATs) are a homologous family of enzymes, which acetylate arylamines, arylhydroxylamines, and arylhydrazines by acetyl transfer from acetyl-coenzyme A (Ac-CoA) and are found in many organisms . NAT was first identified as the enzyme responsible for the inactivation of the anti-tubercular drug isoniazid in humans . The three-dimensional structure of NAT from Salmonella typhimurium has been resolved and shown to have three distinct domains and an active site catalytic triad composed of "Cys(69)-His(107)-Asp(122)," which is typical of hydrolytic enzymes such as the cysteine proteases . The crystal unit cell consists of a dimer of tetramers, with the C terminus of individual monomers juxtaposed . To investigate the function of the first two domains of full-length NAT from S . typhimurium and to investigate the role of the C terminus of NAT, truncation mutants were made with either the C-terminal undecapeptide or the entire third domain (85 amino acids) missing . Unlike the full-length NAT protein (281 amino acids), the truncation mutants of NAT from S . typhimurium are toxic when overexpressed intracellularly in Escherichia coli . Full-length NAT hydrolyses Ac-CoA but only in the presence of an arylamine substrate . Both truncation mutants, however, hydrolyze Ac-CoA even in the absence of arylamine substrate, illustrating that the C-terminal undecapeptide controls hydrolysis of Ac-CoA by NAT from S . typhimurium. Zhonghua Yi Xue Za Zhi, 2001 May 25, 81(10), 613 - 6 {Construction of attenuated Salmonella typhimurium vaccine strain expressing Helicobacter pylori catalase and observation on its protective immunity}; Liao W et al.; OBJECTIVE: To investigated the effect of attenuated Salmonella typhimurium vaccine strain expressing Helicobacter pylori (Hp) catalase (KatA) on protection against Hp infection . METHODS: Recombinant plasmid expressing KatA was constructed . Expression of KatA was induced with IPTG, and analyzed by SDS-PAGE and Western blot . The recombinant plasmid were introduced into attenuated Salmonella typhimurium SL3261 strain to construct live oral vaccine strain . C57BL/6 mice was orally immunized with this vaccine strain and then given orogastric challenge with live Hp Sydney strain . The stomach samples were submitted to a rapid urease test and quantitative culture . RESULTS: The SDS-PAGE showed a dominant additional protein with molecular weight of 79kDa which could specially react with antibody against GST and accounted for 19% of total bacteria proteins . Animal experiment indicated that this vaccine strain could protect mice against Hp infection . CONCLUSION: Attenuated Salmonella typhimurium vaccine strain expressing KatA could induce effective immune response in protection against Hp infection,which may play an important role in preventing and treating Hp infection and related diseases. Immunopharmacol Immunotoxicol, 2001 Nov, 23(4), 519 - 30 Immunization of mice against Salmonella typhimurium using different DNA preparations; Kalfayan LH et al.; Groups of female BALB/c mice were given primary and booster injections of whole genomic DNA extracted from S . typhimurium, P . aeruginosa, or S . aureus . Other groups of mice were immunized in a similar manner with the 1.57kb fragment of the mouse virulence gene (mviA), pTargeT vector (plasmid DNA)/1.57kb construct, pTargeT vector, or saline . Mice in all groups were challenged intraperitoneally with 100 LD50 of S . typhimurium . The bacterial genomic DNA was extracted using the Pure Gene extraction kit . Specific primers were used to amplify the 1.57kb fragment by PCR . The pTargeT Mammalian Expression Vector System was used to prepare the plasmid/ 1.57kb construct . Bacterial genomic DNA extracted from P . aeruginosa and S . aureus appeared to induce non-specific resistance in mice . Specific, in addition to non-specific resistance appeared to be induced when genomic DNA from S . typhimurium was used . There was a prolongation of survival in the groups of mice that received either the 1.57kb fragment or the pTargeT vector/1.57kb construct and 16.67% and 33.34% respectively, of mice in each group survived at 40 days post challenge . None of the mice in the saline control group survived by day 7 post challenge . It is suggested that the non-specific resistance observed in this study might have been due to the adjuvant effect of the non-methylated CpG and other immunostimulatory motifs in bacterial DNA . Specific resistance obtained when genomic DNA from S . typhimurium was used might have been due to minute antigenic contamination, or virulence factor genes other than the mviA gene, might have been expressed in the host, which induced specific immunity. Int J Food Microbiol, 2001 Dec 30, 71(2-3), 235 - 44 Chitosan disrupts the barrier properties of the outer membrane of gram-negative bacteria; Helander IM et al.; The mode of antimicrobial action of chitosan (polymeric beta-1,4-N-acetylglucosamine) on gram-negative bacteria was studied with special emphasis on its ability to bind to and weaken the barrier function of the outer membrane (OM) . Chitosan (250 ppm) at pH 5.3 induced significant uptake of the hydrophobic probe 1-N-phenylnaphthylamine (NPN) in Escherichia coli, Pseudomonas aeruginosa and Salmonella typhimurium . The effect was reduced (E . coli, salmonellae) or abolished (P . aeruginosa) by MgCl2 . No NPN uptake was observed during exposure of the salmonellae to chitosan at pH 7.2 . Chitosan also sensitized P . aeruginosa and the salmonellae to the lytic effect of sodium dodecyl sulfate (SDS); such sensitization was not blocked by MgCl2 and was reversible by washing chitosan-treated cells prior to SDS exposure . Chemical and electrophoretic analyses of cell-free supernatants of chitosan-treated cell suspensions showed that interaction of chitosan with E . coli and the salmonellae involved no release of lipopolysaccharide (LPS) or other membrane lipids . However, chitosan rendered E . coli more sensitive to the inhibitory action of dyes and bile acids used in selective media . Highly cationic mutants of S . typhimurium were more resistant to chitosan than the parent strains . Electron microscopy showed that chitosan caused extensive cell surface alterations and covered the OM with vesicular structures . Chitosan thus appeared to bind to the outer membrane, explaining the loss of the barrier function . This property makes chitosan a potentially useful indirect antimicrobial for food protection. Int J Food Microbiol, 2001 Dec 30, 71(2-3), 211 - 8 Kinetic analysis of the bactericidal action of heated scallop-shell powder; Sawai J et al.; Shell powder of scallop (Patinopecten yessoensis) was exposed to heat treatment at between 200 and 1000 degrees C, and the bactericidal action of the powder slurry was investigated . Shell powder heated at 700 degrees C or higher exhibited bactericidal action against Escherichia coli, Salmonella typhimurium, Staphylococcus aureus and Bacillus subtilis (vegetative cells) . The death of bacteria in the shell powder slurry followed first-order reaction kinetics, and the apparent death rate constant (k) was determined . An increase in exposure temperature enhanced the bactericidal action . The bactericidal action is due to calcium oxide that is converted from calcium carbonate, which is the main component of the shell powder, by heat treatment . The slurry temperature is found to significantly affect the bactericidal action of the shell powder . The slope of the Arrhenius plot of k for E . coli and S . aureus that were grown at 37 degrees C exhibited a discontinuous point at approximately 22 degrees C, at which the values of activation energy for the death of bacteria in the powder slurry changed . This temperature corresponds to that of the phase transition of cell membrane lipids . The bactericidal action of the shell powder is greater than that of a NaOH solution of identical pH . Although the pH of the shell powder slurry is high, the slurry was considered to possess other antibacterial mechanisms in addition to that of alkalinity. Proteomics, 2002 Jan, 2(1), 85 - 93 Proteome study of Francisella tularensis live vaccine strain-containing phagosome in Bcg/Nramp1 congenic macrophages: resistant allele contributes to permissive environment and susceptibility to infection; Kovarova H et al.; The phagocytosis of pathogens by macrophages classically initiates maturation of the phagosome that involves a dynamic exchange of phagosomal components with intracellular compartments of the endocytic pathway . The intracellular microorganisms have developed sophisticated mechanisms to sense environmental conditions and respond to them by phenotypic alterations that ensure their adaptation, survival and proliferation inside the cell . They have learned also to utilise host cellular components to ensure own survival . Recent results suggest that the Bcg locus/Nramp1 gene (natural resistance-associated macrophage protein 1) controls natural resistance to infection by Francisella tularensis LVS (live vaccine strain) and its effect is opposite to that observed for other Bcg/Nramp1-controlled pathogens such as several mycobacterial species, Leischmania donovani, and Salmonella typhimurium . In the case of F . tularensis LVS infection, the mutant allele of the Bcg locus (Bcg(s)/Nramp1(s)) is associated with natural resistance and, inversely, the wild type allele (Bcg(r)/Nramp1(r)) confers susceptibility . To determine whether differential allelic expression of the Bcg locus/Nramp1 gene modifies the composition of F . tularensis LVS-containing phagosomes (FCP), we have utilised an approach where we isolated FCP from infected Bcg congenic B10R (Bcg(r)/Nramp1(r)) and B10S (Bcg(s)/Nramp1(s)) macrophages of susceptible and resistant phenotype, respectively . Comparative proteomic analysis of the two phagosomal compartments with subsequent mass spectrometric analysis allowed identification of several proteins typical for FCP from B10R macrophages . They include a bacterial hypothetical 23 kDa protein, 60 kDa chaperonin GroEL, and host putative proteins that appeared to be mitochondrial ATP synthase beta-chain and NADH-ubiquinone oxidoreductase based on high cross-species homology . High abundance of the hypothetical 23 kDa protein correlates with the susceptible phenotype and, possibly, pathogenicity of F . tularensis LVS . The results demonstrate that F . tularensis LVS can exploit ion transport function of Bcg/Nramp1 to its own advantage. FEMS Microbiol Lett, 2002 Jan 2, 206(1), 93 - 7 Aminoguanidine renders inducible nitric oxide synthase knockout mice more susceptible to Salmonella typhimurium infection; Zhou X et al.; Aminoguanidine (AG), a nitric oxide synthase (NOS) inhibitor, has been widely used to study the role of inducible NOS (iNOS) in host defense against infections caused by various pathogens including Salmonella typhimurium . iNOS has been reported to play an important role in host defense against S . typhimurium infection both in vitro and in vivo . In this report we show those AG treatment lead to weight loss in both wild-type and iNOS knockout mice, and rendered them more susceptible to Salmonella infection . These results suggest that AG may have side effects other than the inhibition of iNOS, and that data obtained from studies using AG should be interpreted with caution. Avian Dis, 2001 Oct-Dec, 45(4), 962 - 71 Differences in abilities to colonize reproductive organs and to contaminate eggs in intravaginally inoculated hens and in vitro adherences to vaginal explants between Salmonella enteritidis and other Salmonella serovars; Okamura M et al.; In Experiment 1, mature laying hens were inoculated intravaginally with 10(6) colony-forming units of Salmonella enterica serovar enteritidis (S . enteritidis), Salmonella typhimurium, Salmonella infantis, Salmonella hadar, Salmonella heidelberg, or Salmonella montevideo to compare their abilities to colonize the reproductive organs of chickens and to contaminate eggs . Salmonella enteritidis was more frequently recovered (from 11 of 40 eggs, 27.5%) than the other serovars, and especially the inner shell was contaminated with these organisms in 10 of 40 eggs (25.0%) . The contamination rates and the viable counts in cloaca were significantly (P < 0.05) higher in hens inoculated with S . enteritidis than in those inoculated with the other serovars at 4 days postinoculation (PI) . In the vagina, the positive rates were 90%-100% in hens inoculated with S . enteritidis, and the viable counts of the organisms in this portion were significantly (P < 0.05) higher than those of the other serovars at 2, 4, and 7 days PI . The ceca were colonized similarly by each serovar at 7 days PI . The spleen and ovary were infected with S . enteritidis in three and one hen, respectively . No Salmonella was recovered from liver and peripheral blood in any hen . Salmonella enteritidis was recovered from other oviductal portions than the vagina (10%-20%), whereas no forming egg was contaminated in the oviduct . In Experiment 2, the in vitro adherence of these six serovars to the vaginal epithelium was compared with vaginal explants . The mean number of S . enteritidis attaching to the secondary villi in the vaginal lumen was significantly (P < 0.05) higher than those of the other serovars . These results suggest that S . enteritidis has a specific advantage over the other Salmonella serovars by its capacity to colonize the vaginal tissues of hens, and this higher affinity of S . enteritidis to the vagina may play a significant role in the production of many S . enteritidis-contaminated eggs. Avian Dis, 2001 Oct-Dec, 45(4), 922 - 37 Pathogenicity of different serogroups of avian salmonellae in specific-pathogen-free chickens; Roy P et al.; The pathogenicity of one isolate of Salmonella typhimurium, four isolates of Salmonella heidelberg, three isolates of Salmonella kentucky, two isolates of Salmonella montevideo, one isolate of Salmonella hadar, and two isolates of Salmonella enteritidis (SE), one belonging to phage type (PT)13a and the other to PT34, was investigated in specific-pathogen-free chicks . Three hundred eighty-four chicks were separated into 16 equal groups of 24 chicks . Thirteen groups were inoculated individually with 0.5 ml of broth culture containing 1 x 10(7) colony-forming units (CFU) of either S . typhimurium (one source), S . heidelberg (four sources), S . montevideo (two sources), S . hadar (one source), S . kentucky (three sources), SE PT 13a (one source) or SE PT 34 (one source) by crop gavage . Two groups of 24 chicks were inoculated in the same way with 1 x 10(7) CFU of SE PT4 (chicken-CA) and Salmonella pullorum . Another group of 24 chicks was kept as an uninoculated control group . The chicks were observed daily for clinical signs and mortality . Isolation of salmonella was done from different organs at 7 and 28 days postinoculation (DPI) . All the chicks were weighed individually at 7, 14, 21, and 28 DPI . Two chicks chosen at random from each group were euthanatized and necropsied at 7 and 14 DPI and all the remaining live chickens, at 28 DPI . Selected tissues were taken for histopathology at 7 and 14 DPI . Dead chicks were examined for gross lesions and tissues were collected for histopathology . Chicks inoculated with S . pullorum had the highest mortality (66.66%), followed by S . typhimurium (33.33%) . Chicks inoculated with S . heidelberg (00-1105-2) and SE PT4 (chicken-CA) had 12.5% mortality and 8.3% mortality, respectively, with SE PT 13a . Ceca were 100% positive for salmonellae at acute or chronic infection compared with other organs . Mean body weight reduction ranged from 0.67% (inoculated with S . kentucky 00-926-2) to 33.23% (inoculated with S . typhimurium 00-372) in the inoculated groups at different weeks compared with uninoculated controls . Gross and microscopic lesions included peritonitis, perihepatitis, yolk sac infection, typhilitis, pneumonia, and enteritis in some groups, especially those inoculated with S . typhimurium, S . heidelberg (00-1 105-2), SE PT4 (chicken-CA), and S . pullorum. Microbiology, 2002 Jan, 148(Pt 1), 123 - 31 Regulation of carbon utilization by sulfur availability in Escherichia coli and Salmonella typhimurium; Qua