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Author (up) Arimoto-Kobayashi, S.; Sakata, H.; Mitsu, K.; Tanoue, H. file  url
  Title A possible photosensitizer: Tobacco-specific nitrosamine, 4-(N-methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), induced mutations, DNA strand breaks and oxidative and methylative damage with UVA Type Journal Article
  Year 2007 Publication Mutation Research Abbreviated Journal Mutat Res  
  Volume 632 Issue 1-2 Pages 111-120  
  Keywords Base Sequence; DNA Breaks; DNA Methylation--drug effects, radiation effects; Dose-Response Relationship, Drug; Models, Biological; Molecular Sequence Data; Mutation; Nitrosamines--toxicity; Oxidative Stress--drug effects, radiation effects; Photosensitizing Agents--toxicity; Salmonella typhimurium; Tobacco--chemistry; Ultraviolet Rays--adverse effects  
  Abstract We discovered the directly acting mutagenicity of the tobacco-specific nitrosamine, 4-(N-methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), with UVA light (320-400nm) in Ames bacteria and phage M13mp2 in the absence of metabolic activation. We have investigated the spectrum of mutations caused by UVA-activated NNK. The majority (57%) of induced sequence changes were comprised of GC to CG, GC to TA and GC to AT. This suggested that modification of guanine residues was responsible for these mutations. Hence, we explored the formation of 7,8-dihydro-8-oxo-2'-deoxyguanosine (8-oxodG) and O(6)-methylguanine (O(6)meG) in the DNA. When calf thymus DNA was treated with NNK and UVA, the amount of 8-oxodG/dG and O(6)meG/G in the DNA increased up to 20-fold and 100-fold, respectively, compared with the untreated control. DNA strand breaks were observed following NNK and UVA treatment, and the strand breaks were suppressed in the presence of scavengers for oxygen and NO radical. The formation of NO was also observed in NNK solutions irradiated with UVA. We analyzed the photodynamic spectrum of mutation induction, 8-oxodG formation and NO formation using monochromatic radiation. The patterns of the action spectra were comparable to the absorption spectrum of NNK. We conclude that NNK may act as a photosensitizer in response to UVA to produce NO and other oxidative and alkylative intermediates following the formation of 8-oxodG and O(6)meG in DNA, which may lead to mutations and DNA strand breaks.  
  Call Number Serial 86  
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Author (up) Brooks, J.P.; Adeli, A.; McLaughlin, M.R. file  url
  Title Microbial ecology, bacterial pathogens, and antibiotic resistant genes in swine manure wastewater as influenced by three swine management systems Type Journal Article
  Year 2014 Publication Water Research Abbreviated Journal Water Res  
  Volume 57 Issue Pages 96-103  
  Keywords Animal Husbandry/*methods; Animals; Anti-Bacterial Agents/pharmacology; Bacteria/drug effects/*genetics/*isolation & purification; Bacterial Proteins/genetics/metabolism; Drug Resistance, Bacterial/*genetics; Manure/*microbiology; Methicillin-Resistant Staphylococcus aureus/drug effects/genetics/isolation & purification; *Microbiota; RNA, Ribosomal, 16S/genetics/metabolism; Real-Time Polymerase Chain Reaction; Southeastern United States; Sus scrofa; Waste Water/*microbiology; Antibiotic resistance; Campylobacter; Confined animal feeding operation (CAFO); Lagoon wastewater; Salmonella; Swine; Microbiome  
  Abstract The environmental influence of farm management in concentrated animal feeding operations (CAFO) can yield vast changes to the microbial biota and ecological structure of both the pig and waste manure lagoon wastewater. While some of these changes may not be negative, it is possible that CAFOs can enrich antibiotic resistant bacteria or pathogens based on farm type, thereby influencing the impact imparted by the land application of its respective wastewater. The purpose of this study was to measure the microbial constituents of swine-sow, -nursery, and -finisher farm manure lagoon wastewater and determine the changes induced by farm management. A total of 37 farms were visited in the Mid-South USA and analyzed for the genes 16S rRNA, spaQ (Salmonella spp.), Camp-16S (Campylobacter spp.), tetA, tetB, ermF, ermA, mecA, and intI using quantitative PCR. Additionally, 16S rRNA sequence libraries were created. Overall, it appeared that finisher farms were significantly different from nursery and sow farms in nearly all genes measured and in 16S rRNA clone libraries. Nearly all antibiotic resistance genes were detected in all farms. Interestingly, the mecA resistance gene (e.g. methicillin resistant Staphylococcus aureus) was below detection limits on most farms, and decreased as the pigs aged. Finisher farms generally had fewer antibiotic resistance genes, which corroborated previous phenotypic data; additionally, finisher farms produced a less diverse 16S rRNA sequence library. Comparisons of Camp-16S and spaQ GU (genomic unit) values to previous culture data demonstrated ratios from 10 to 10,000:1 depending on farm type, indicating viable but not cultivatable bacteria were dominant. The current study indicated that swine farm management schemes positively and negatively affect microbial and antibiotic resistant populations in CAFO wastewater which has future “downstream” implications from both an environmental and public health perspective.  
  Call Number Serial 1943  
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Author (up) Girennavar, B.; Cepeda, M.L.; Soni, K.A.; Vikram, A.; Jesudhasan, P.; Jayaprakasha, G.K.; Pillai, S.D.; Patil, B.S. file  url
  Title Grapefruit juice and its furocoumarins inhibits autoinducer signaling and biofilm formation in bacteria Type Journal Article
  Year 2008 Publication International Journal of Food Microbiology Abbreviated Journal Int J Food Microbiol  
  Volume 125 Issue 2 Pages 204-208  
  Keywords Analysis of Variance; Beverages; Biofilms/*growth & development; Biomass; Citrus paradisi; Colony Count, Microbial; Escherichia coli O157/drug effects/physiology; Food Contamination/*prevention & control; Food Microbiology; Furocoumarins/isolation & purification/*pharmacology; Gram-Negative Bacteria/drug effects/*physiology; Gram-Positive Bacteria/drug effects/*physiology; Pseudomonas aeruginosa/drug effects/physiology; Quorum Sensing; Salmonella typhimurium/drug effects/physiology; Signal Transduction  
  Abstract Cell-to-cell communications in bacteria mediated by small diffusible molecules termed as autoinducers (AI) are known to influence gene expression and pathogenicity. Oligopeptides and N-acylhomoserine lactones (AHL) are major AI molecules involved in intra-specific communication in gram-positive and gram-negative bacteria respectively, whereas boronated-diester molecules (AI-2) are involved in inter-specific communication among both gram-positive and gram-negative bacteria. Naturally occurring furocoumarins from grapefruit showed >95% inhibition of AI-1 and AI-2 activities based on the Vibrio harveyi based autoinducer bioassay. Grapefruit juice and furocoumarins also inhibited biofilm formation by Escherichia coli O157:H7, Salmonella typhimurium and Pseudomonas aeruginosa. These results suggest that grape fruit juice and furocoumarins could serve as a source to develop bacterial intervention strategies targeting microbial cell signaling processes.  
  Call Number Serial 1579  
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Author (up) Kim, T.; Bak, G.; Lee, J.; Kim, K.-S. file  url
  Title Systematic analysis of the role of bacterial Hfq-interacting sRNAs in the response to antibiotics Type Journal Article
  Year 2015 Publication The Journal of Antimicrobial Chemotherapy Abbreviated Journal J Antimicrob Chemother  
  Volume 70 Issue 6 Pages 1659-1668  
  Keywords Adaptation, Physiological; Anti-Bacterial Agents/*pharmacology; Escherichia coli/*drug effects/genetics/growth & development; Gene Expression Profiling; Gene Expression Regulation, Bacterial; Gene Knockout Techniques; Host Factor 1 Protein/genetics/*metabolism; Humans; Microbial Sensitivity Tests; Microbial Viability/drug effects; RNA, Small Untranslated/genetics/*metabolism; Salmonella/*drug effects/genetics/growth & development; Stress, Physiological; Hfq protein; multidrug resistance; small non-coding RNA; species conservation  
  Abstract OBJECTIVES: To systematically analyse the interplay between the expression of Hfq-associated small non-coding RNAs (sRNAs) and antibiotic susceptibility in Gram-negative bacteria. METHODS: To identify the roles of sRNAs in the antibiotic susceptibility of Escherichia coli and Salmonella species, susceptibility tests, growth analyses and viability assays were performed using E. coli Hfq-associated sRNAs from overexpression libraries. Prediction, susceptibility testing of gene knockouts and expression analysis of target genes under conditions of sRNA overexpression or knockout were performed to identify candidate targets for modulating antibiotic susceptibility. RESULTS: The susceptibilities of E. coli strains overexpressing each of the 26 known Hfq-dependent sRNAs to major classes of antibiotics were determined. Induced expression of 17 sRNAs modulated the susceptibility of E. coli to antibiotics. Among them, four sRNA knockout strains partially or completely reversed susceptibility phenotypes of sRNA overexpression. The phenotype of OxyS, RseX or MicF was not entirely dependent on the presence of Hfq protein, in contrast to the dependency of previously characterized roles. The function of eight of nine sRNAs was found to be conserved in the response to antibiotics in Salmonella. Some MicF- or RyeB-mediated cellular target genes and pathways that may be important for the regulation of antibiotic susceptibility were identified. Finally, the overexpression of RyeB potentiated the efficacy of levofloxacin against MDR strains. CONCLUSIONS: Our data indicate that Hfq-associated sRNAs potentially enable bacteria to adapt to antibiotic challenges via multifaceted approaches. Therefore, sRNA-based applications will form a new antibiotic arsenal for combating the rise in antibiotic resistance.  
  Call Number Serial 1588  
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Author (up) Knothe, H.; Shah, P.; Krcmery, V.; Antal, M.; Mitsuhashi, S. file  url
  Title Transferable resistance to cefotaxime, cefoxitin, cefamandole and cefuroxime in clinical isolates of Klebsiella pneumoniae and Serratia marcescens Type Journal Article
  Year 1983 Publication Infection Abbreviated Journal Infection  
  Volume 11 Issue 6 Pages 315-317  
  Keywords Cefamandole/*pharmacology; Cefotaxime/*pharmacology; Cefoxitin/*pharmacology; Cefuroxime/*pharmacology; Cephalosporins/*pharmacology; *Conjugation, Genetic; Escherichia coli/drug effects/genetics; Humans; Klebsiella pneumoniae/drug effects/*genetics; Proteus mirabilis/drug effects/genetics; *R Factors; Salmonella typhimurium/drug effects/genetics; Serratia marcescens/drug effects/*genetics  
  Abstract In conjugational crosses, three Klebsiella pneumoniae strains and one Serratia marcescens strain have been demonstrated to transfer resistance determinants to newer types of cephalosporins. While Klebsiella strains donated cefotaxime, cefamandole and cefuroxime resistance to Escherichia coli K-12 recipients, the genetic analysis of exconjugants after the transfer of plasmids from Serratia strains to Proteus or Salmonella recipients showed that the cefoxitin resistance determinant was also co-transferred. In subsequent transfer cycles of this plasmid, cefotaxime and cefoxitin resistance determinants segregated in contrast to the relative stability of plasmids derived from Klebsiella strains in subsequent transfer cycles. From results obtained in this study, it may be concluded that in some strains of nosocomial Enterobacteriaceae, resistance to newer cephalosporins could be transmissible and thus plasmid-located.  
  Call Number Serial 494  
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Author (up) Lievin-Le Moal, V.; Amsellem, R.; Servin, A.L. file  url
doi  openurl
  Title Impairment of swimming motility by antidiarrheic Lactobacillus acidophilus strain LB retards internalization of Salmonella enterica serovar Typhimurium within human enterocyte-like cells Type Journal Article
  Year 2011 Publication Antimicrobial Agents and Chemotherapy Abbreviated Journal Antimicrob Agents Chemother  
  Volume 55 Issue 10 Pages 4810-4820  
  Keywords Actins/antagonists & inhibitors/metabolism; Bacterial Adhesion; Bacterial Proteins/metabolism; Caco-2 Cells; Cell Membrane/physiology; Cells, Cultured; Enterocytes/*microbiology; Flagella/*physiology; Humans; Lactobacillus acidophilus/*physiology; Microbial Viability; Movement; *Probiotics; Salmonella typhimurium/pathogenicity/*physiology; Time-Lapse Imaging  
  Abstract We report that both culture and the cell-free culture supernatant (CFCS) of Lactobacillus acidophilus strain LB (Lacteol Boucard) have the ability (i) to delay the appearance of Salmonella enterica serovar Typhimurium strain SL1344-induced mobilization of F-actin and, subsequently, (ii) to retard cell entry by S. Typhimurium SL1344. Time-lapse imaging and Western immunoblotting showed that S. Typhimurium SL1344 swimming motility, as represented by cell tracks of various types, was rapidly but temporarily blocked without affecting the expression of FliC flagellar propeller protein. We show that the product(s) secreted by L. acidophilus LB that supports the inhibitory activity is heat stable and of low molecular weight. The product(s) caused rapid depolarization of the S. Typhimurium SL1344 cytoplasmic membrane without affecting bacterial viability. We identified inhibition of swimming motility as a newly discovered mechanism by which the secreted product(s) of L. acidophilus strain LB retards the internalization of the diarrhea-associated pathogen S. enterica serovar Typhimurium within cultured human enterocyte-like cells.  
  Call Number Serial 1061  
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Author (up) Sengun, I.Y.; Karapinar, M. file  url
  Title Effectiveness of lemon juice, vinegar and their mixture in the elimination of Salmonella typhimurium on carrots (Daucus carota L.) Type Journal Article
  Year 2004 Publication International Journal of Food Microbiology Abbreviated Journal Int J Food Microbiol  
  Volume 96 Issue 3 Pages 301-305  
  Keywords Acetic Acid/*pharmacology; Citrus/*chemistry; Colony Count, Microbial; Consumer Product Safety; Daucus carota/*microbiology; Disinfectants/*pharmacology; Food Contamination/prevention & control; Food Microbiology; Plant Extracts/*pharmacology; Salmonella typhimurium/*drug effects/growth & development; Time Factors  
  Abstract Lemon juice, vinegar and the mixture of lemon juice and vinegar (1:1) were tested for their effectiveness in reducing the counts of inoculated Salmonella typhimurium (approximately 6 and 3 log cfu/g) on carrots. Treatment of carrot samples with lemon juice vinegar alone for different exposure times (0, 15, 30 and 60 min) caused significant reductions ranging between 0.79-3.95 and 1.57-3.58 log cfu/g, respectively, while the number of pathogens was reduced to an undetectable level after 30-min treatment by combined used lemon juice vinegar.  
  Call Number Serial 1724  
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Author (up) Shin, S.; Brodsky, I.E. file  url
  Title The inflammasome: Learning from bacterial evasion strategies Type Journal Article
  Year 2015 Publication Seminars in Immunology Abbreviated Journal Semin Immunol  
  Volume 27 Issue 2 Pages 102-110  
  Keywords Animals; Bacteria/immunology; Bacterial Infections/*immunology; Humans; *Immune Evasion; Inflammasomes/*immunology; Receptors, Pattern Recognition/immunology; Caspase-1; Inflammasome; Microbial evasion; Salmonella; Yersinia  
  Abstract The innate immune system plays a critical role in defense against microbial infection and employs germline-encoded pattern recognition receptors to detect broadly conserved microbial structures or activities. Pattern recognition receptors of the nucleotide binding domain/leucine rich repeat (NLR) family respond to particular microbial products or disruption of cellular physiology, and mediate the activation of an arm of the innate immune response termed the inflammasome. Inflammasomes are multiprotein complexes that are inducibly assembled in response to the contamination of the host cell cytosol by microbial products. Individual NLRs sense the presence of their cognate stimuli, and initiate assembly of inflammasomes via the adaptor protein apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) and the effector pro-enzyme caspase-1. Inflammasome activation leads to rapid release of pro-inflammatory mediators of the IL-1 family as well as the release of intracellular alarmins due to a lytic form of programmed cell death termed pyroptosis. Over the past 15 years, a great deal has been learned about the mechanisms that drive inflammasome activation in response to infection by diverse pathogens. However, pathogens have also evolved mechanisms to evade or suppress host defenses, and the mechanisms by which pathogens evade inflammasome activation are not well-understood. Here, we will discuss emerging evidence on how diverse pathogens evade inflammasome activation, and what these studies have revealed about inflammasome biology. Deeper understanding of pathogen evasion of inflammasome activation has the potential to lead to development of novel classes of immunomodulatory factors that could be used in the context of human inflammatory diseases.  
  Call Number Serial 1702  
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Author (up) Vikram, A.; Jesudhasan, P.R.; Jayaprakasha, G.K.; Pillai, S.D.; Jayaraman, A.; Patil, B.S. file  url
  Title Citrus flavonoid represses Salmonella pathogenicity island 1 and motility in S. Typhimurium LT2 Type Journal Article
  Year 2011 Publication International Journal of Food Microbiology Abbreviated Journal Int J Food Microbiol  
  Volume 145 Issue 1 Pages 28-36  
  Keywords Bacterial Adhesion/drug effects; Bacterial Proteins/drug effects; Biofilms/drug effects/growth & development; Cell Line, Tumor; Citrus/*chemistry; Flagella/drug effects; Flavanones/*pharmacology; Gene Expression Profiling; Gene Expression Regulation, Bacterial; *Genomic Islands; Humans; Oligonucleotide Array Sequence Analysis; Salmonella typhimurium/*drug effects/genetics/growth & development/pathogenicity; Virulence  
  Abstract Salmonellosis is one of the leading health problems worldwide. With the rise of drug resistance strains, it has become imperative to identify alternative strategies to counter bacterial infection. Natural products were used historically to identify novel compounds with various bioactivities. Citrus species is a rich source of flavonoids. Naringenin, a flavonone, is present predominantly in grapefruit. Previously we have demonstrated that naringenin is potent inhibitor of cell-cell signaling. The current study was undertaken to understand the effect of naringenin on Salmonella Typhimurium LT2. The cDNA microarrays were employed to study the response of S. Typhimurium to naringenin treatment. Naringenin specifically repressed 24 genes in the Salmonella pathogenicity island 1 and down-regulated 17 genes involved in flagellar and motility. Furthermore, phenotypic assays support the result of microarray analysis. In addition, naringenin seems to repress SPI-1 in pstS/hilD-dependent manner. Altogether the data suggest that naringenin attenuated S. Typhimurium virulence and cell motility. This is the first molecular evidence to demonstrate effect of naringenin on bacterial virulence and cell motility.  
  Call Number Serial 1580  
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