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Sample records for activities involving bacterial

  1. The formyl peptide receptor like-1 and scavenger receptor MARCO are involved in glial cell activation in bacterial meningitis

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    Jansen Sandra

    2011-02-01

    Full Text Available Abstract Background Recent studies have suggested that the scavenger receptor MARCO (macrophage receptor with collagenous structure mediates activation of the immune response in bacterial infection of the central nervous system (CNS. The chemotactic G-protein-coupled receptor (GPCR formyl-peptide-receptor like-1 (FPRL1 plays an essential role in the inflammatory responses of host defence mechanisms and neurodegenerative disorders such as Alzheimer's disease (AD. Expression of the antimicrobial peptide cathelicidin CRAMP/LL-37 is up-regulated in bacterial meningitis, but the mechanisms underlying CRAMP expression are far from clear. Methods Using a rat meningitis model, we investigated the influence of MARCO and FPRL1 on rCRAMP (rat cathelin-related antimicrobial peptide expression after infection with bacterial supernatants of Streptococcus pneumoniae (SP and Neisseria meningitides (NM. Expression of FPRL1 and MARCO was analyzed by immunofluorescence and real-time RT-PCR in a rat meningitis model. Furthermore, we examined the receptor involvement by real-time RT-PCR, extracellular-signal regulated kinases 1/2 (ERK1/2 phosphorylation and cAMP level measurement in glial cells (astrocytes and microglia and transfected HEK293 cells using receptor deactivation by antagonists. Receptors were inhibited by small interference RNA and the consequences in NM- and SP-induced Camp (rCRAMP gene expression and signal transduction were determined. Results We show an NM-induced increase of MARCO expression by immunofluorescence and real-time RT-PCR in glial and meningeal cells. Receptor deactivation by antagonists and small interfering RNA (siRNA verified the importance of FPRL1 and MARCO for NM- and SP-induced Camp and interleukin-1β expression in glial cells. Furthermore, we demonstrated a functional interaction between FPRL1 and MARCO in NM-induced signalling by real-time RT-PCR, ERK1/2 phosphorylation and cAMP level measurement and show differences between

  2. Antimicrobial activity of plant essential oils against bacterial and fungal species involved in food poisoning and/or food decay.

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    Lixandru, Brînduşa-Elena; Drăcea, Nicoleta Olguţa; Dragomirescu, Cristiana Cerasella; Drăgulescu, Elena Carmina; Coldea, Ileana Luminiţa; Anton, Liliana; Dobre, Elena; Rovinaru, Camelia; Codiţă, Irina

    2010-01-01

    The currative properties of aromatic and medicinal plants have been recognized since ancient times and, more recently, the antimicrobial activity of plant essential oils has been used in several applications, including food preservation. The purpose of this study was to create directly comparable, quantitative data on the antimicrobial activity of some plant essential oils prepared in the National Institute of Research-Development for Chemistry and Petrochemistry, Bucharest to be used for the further development of food packaging technology, based on their antibacterial and antifungal activity. The essential oils extracted from thyme (Thymus vulgaris L.), basil (Ocimum basilicum L.), coriander (Coriandrum sativum L.), rosemary (Rosmarinus officinalis L.), sage (Salvia officinalis L.), fennel (Foeniculum vulgare L.), spearmint (Mentha spicata L.) and carraway (Carum carvi L.) were investigated for their antimicrobial activity against eleven different bacterial and three fungal strains belonging to species reported to be involved in food poisoning and/or food decay: S. aureus ATCC 25923, S. aureus ATCC 6538, S. aureus ATCC 25913, E. coli ATCC 25922, E. coli ATCC 35218, Salmonella enterica serovar Enteritidis Cantacuzino Institute Culture Collection (CICC) 10878, Listeria monocytogenes ATCC 19112, Bacillus cereus CIP 5127, Bacillus cereus ATCC 11778, Candida albicans ATCC 10231, Aspergillus niger ATCC 16404, Penicillium spp. CICC 251 and two E. coli and Salmonella enterica serovar Enteritidis clinical isolates. The majority of the tested essential oils exibited considerable inhibitory capacity against all the organisms tested, as supported by growth inhibition zone diameters, MICs and MBC's. Thyme, coriander and basil oils proved the best antibacterial activity, while thyme and spearmint oils better inhibited the fungal species.

  3. The bacterial two-hybrid system uncovers the involvement of acetylation in regulating of Lrp activity in Salmonella Typhimurium

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    Ran Qin

    2016-11-01

    Full Text Available Nε-lysine acetylation is an abundant and important Post-translational modification in bacteria. We used the bacterial two-hybrid system to screen the genome library of the Salmonella Typhimurium to identify potential proteins involved in acetyltransferase Pat - or deacetylase CobB-mediated acetylation. Then, the in vitro (deacetylation assays were used to validate the potential targets, such as STM14_1074, NrdF, RhaR. Lrp, a leucine-responsive regulatory protein and global regulator, was shown to interact with Pat. We further demonstrate that Lrp could be acetylated by Pat and deacetylated by NAD+-dependent CobB in vitro. Specifically, the conserved lysine residue 36 (K36 in helix-turn-helix (HTH DNA-binding domain of Lrp was acetylated. Acetylation of K36 impaired the function of Lrp through altering the affinity with the target promoter. The mutation of K36 in chromosome mimicking acetylation enhanced the transcriptional level of itself and attenuated the mRNA levels of Lrp-regulated genes including fimA, which was confirmed by yeast agglutination assay. These findings demonstrate that the acetylation regulates the DNA-binding activity of Lrp, suggesting that acetylation modification of transcription factors is a conserved regulatory manner to modulate gene expression in bacteria and eukaryotes.

  4. The Bacterial Two-Hybrid System Uncovers the Involvement of Acetylation in Regulating of Lrp Activity in Salmonella Typhimurium

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    Qin, Ran; Sang, Yu; Ren, Jie; Zhang, Qiufen; Li, Shuxian; Cui, Zhongli; Yao, Yu-Feng

    2016-01-01

    N𝜀-lysine acetylation is an abundant and important Post-translational modification in bacteria. We used the bacterial two-hybrid system to screen the genome library of the Salmonella Typhimurium to identify potential proteins involved in acetyltransferase Pat – or deacetylase CobB-mediated acetylation. Then, the in vitro (de)acetylation assays were used to validate the potential targets, such as STM14_1074, NrdF, RhaR. Lrp, a leucine-responsive regulatory protein and global regulator, was shown to interact with Pat. We further demonstrate that Lrp could be acetylated by Pat and deacetylated by NAD+-dependent CobB in vitro. Specifically, the conserved lysine residue 36 (K36) in helix-turn-helix (HTH) DNA-binding domain of Lrp was acetylated. Acetylation of K36 impaired the function of Lrp through altering the affinity with the target promoter. The mutation of K36 in chromosome mimicking acetylation enhanced the transcriptional level of itself and attenuated the mRNA levels of Lrp-regulated genes including fimA, which was confirmed by yeast agglutination assay. These findings demonstrate that the acetylation regulates the DNA-binding activity of Lrp, suggesting that acetylation modification of transcription factors is a conserved regulatory manner to modulate gene expression in bacteria and eukaryotes. PMID:27909434

  5. Autoinducer-2-like activity on vegetable produce and its potential involvement in bacterial biofilm formation on tomatoes.

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    Lu, Lingeng; Hume, Michael E; Pillai, Suresh D

    2005-01-01

    Quorum sensing employing autoinducer molecules is a strategy used by bacterial populations to coordinately modulate their response to environmental stresses and host defense mechanisms. The objectives of this study were to determine the levels of autoinducer-2 (AI-2)-like activity on selected vegetable produce and determine whether AI-2-like molecules can promote E. coli O157:H7 biofilm formation on tomatoes. Twelve different fruit and vegetable produce samples were screened for AI-2-like activity using autoinducer sensing V. harveyi biosensor strains. All samples except strawberries showed AI-2 activity albeit at varying levels, with eggplant having the highest levels. Tomatoes, when stored at 4 degrees C for 9 days, showed increasing levels of heterotrophic bacterial populations as compared to AI-2-like activity levels, which fluctuated. Rinses from Roma tomato surfaces that were stored at refrigeration temperature for up to 9 days caused a significant increase (1.8-3.6-fold as compared to the negative controls) in biofilm formation by luxS mutant (non AI-2 producing) generic E. coli and E. coli O157:H7 strains using a micro-titer plate-based biofilm assay. These results suggest that AI-2-like activity, which is present on the surfaces of tomatoes, has the potential to enhance the production of bacterial biofilms.

  6. Endolymphatic sac involvement in bacterial meningitis

    DEFF Research Database (Denmark)

    Møller, Martin Nue; Brandt, Christian; Andersen, Christian Østergaard;

    2015-01-01

    The commonest sequelae of bacterial meningitis are related to the inner ear. Little is known about the inner ear immune defense. Evidence suggests that the endolymphatic sac provides some protection against infection. A potential involvement of the endolymphatic sac in bacterial meningitis......-inoculated. The rats were killed when reaching terminal illness or on day 7, followed by light microscopy preparation and PAS-Alcian blue staining. The endolymphatic sac was examined for bacterial invasion and leukocyte infiltration. Neither bacteria nor leukocytes infiltrated the endolymphatic sac during the first...... days. Bacteria invaded the inner ear through the cochlear aquaduct. On days 5-6, the bacteria invaded the endolymphatic sac through the endolymphatic duct subsequent to invasion of the vestibular endolymphatic compartment. No evidence of direct bacterial invasion of the sac through the meninges...

  7. GTPases involved in bacterial ribosome maturation.

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    Goto, Simon; Muto, Akira; Himeno, Hyouta

    2013-05-01

    The ribosome is an RNA- and protein-based macromolecule having multiple functional domains to facilitate protein synthesis, and it is synthesized through multiple steps including transcription, stepwise cleavages of the primary transcript, modifications of ribosomal proteins and RNAs and assemblies of ribosomal proteins with rRNAs. This process requires dozens of trans-acting factors including GTP- and ATP-binding proteins to overcome several energy-consuming steps. Despite accumulation of genetic, biochemical and structural data, the entire process of bacterial ribosome synthesis remains elusive. Here, we review GTPases involved in bacterial ribosome maturation.

  8. Bacterial Extracellular Polysaccharides Involved in Biofilm Formation

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    Elena P. Ivanova

    2009-07-01

    Full Text Available Extracellular polymeric substances (EPS produced by microorganisms are a complex mixture of biopolymers primarily consisting of polysaccharides, as well as proteins, nucleic acids, lipids and humic substances. EPS make up the intercellular space of microbial aggregates and form the structure and architecture of the biofilm matrix. The key functions of EPS comprise the mediation of the initial attachment of cells to different substrata and protection against environmental stress and dehydration. The aim of this review is to present a summary of the current status of the research into the role of EPS in bacterial attachment followed by biofilm formation. The latter has a profound impact on an array of biomedical, biotechnology and industrial fields including pharmaceutical and surgical applications, food engineering, bioremediation and biohydrometallurgy. The diverse structural variations of EPS produced by bacteria of different taxonomic lineages, together with examples of biotechnological applications, are discussed. Finally, a range of novel techniques that can be used in studies involving biofilm-specific polysaccharides is discussed.

  9. Involvement in Physical Activity

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    James Gavin

    2013-04-01

    Full Text Available A total of 1,096 adolescents participated in 123 focus groups regarding the perceived outcomes of their involvement in sports and physical activity (PA. The groups, segmented by grade level, sex, and school types, were conducted in both public and private high schools in Montreal, Quebec. We sought to understand, through the participants’ own words, their perception of the outcome matrix of involvement in sports and PA. Focus group questions emphasized changes that adolescents associated with such engagement. In particular, participants were asked how sports and PA might influence behaviors, emotional states, personal characteristics, and other outcomes. Twelve themes were identified in the responses: Positive Health and Physical Changes (18.5%, Activity-Related Positive Emotions (15.6%, and Personal Learning (11.3% were most prevalent in the discussions. A cluster of deeper personal changes thematically described as Self-Identity, Autonomy, and Positive Character Development accounted for another 16.5% of the responses. Relatively few commentaries emphasized negative effects (7.1%. Converting the proportions of qualitative data into a quantitative index allowed us to analyze potential differences in emphasis according to sex, age, and school type. Though a few significant findings emerged, the larger pattern was of a uniform perceptual map across the variables for this adolescent sample. Implications drawn from this investigation highlight the need to clearly articulate concrete pathways to positive nonphysical changes (e.g., mood states, autonomy, positive character development from engagements in sports and PA.

  10. Autoproteolytic Activation of Bacterial Toxins

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    Aimee Shen

    2010-05-01

    Full Text Available Protease domains within toxins typically act as the primary effector domain within target cells. By contrast, the primary function of the cysteine protease domain (CPD in Multifunctional Autoprocessing RTX-like (MARTX and Clostridium sp. glucosylating toxin families is to proteolytically cleave the toxin and release its cognate effector domains. The CPD becomes activated upon binding to the eukaryotic-specific small molecule, inositol hexakisphosphate (InsP6, which is found abundantly in the eukaryotic cytosol. This property allows the CPD to spatially and temporally regulate toxin activation, making it a prime candidate for developing anti-toxin therapeutics. In this review, we summarize recent findings related to defining the regulation of toxin function by the CPD and the development of inhibitors to prevent CPD-mediated activation of bacterial toxins.

  11. Autoproteolytic Activation of Bacterial Toxins

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    Shen, Aimee

    2010-01-01

    Protease domains within toxins typically act as the primary effector domain within target cells. By contrast, the primary function of the cysteine protease domain (CPD) in Multifunctional Autoprocessing RTX-like (MARTX) and Clostridium sp. glucosylating toxin families is to proteolytically cleave the toxin and release its cognate effector domains. The CPD becomes activated upon binding to the eukaryotic-specific small molecule, inositol hexakisphosphate (InsP6), which is found abundantly in the eukaryotic cytosol. This property allows the CPD to spatially and temporally regulate toxin activation, making it a prime candidate for developing anti-toxin therapeutics. In this review, we summarize recent findings related to defining the regulation of toxin function by the CPD and the development of inhibitors to prevent CPD-mediated activation of bacterial toxins. PMID:22069620

  12. Autoproteolytic activation of bacterial toxins.

    Science.gov (United States)

    Shen, Aimee

    2010-05-01

    Protease domains within toxins typically act as the primary effector domain within target cells. By contrast, the primary function of the cysteine protease domain (CPD) in Multifunctional Autoprocessing RTX-like (MARTX) and Clostridium sp. glucosylating toxin families is to proteolytically cleave the toxin and release its cognate effector domains. The CPD becomes activated upon binding to the eukaryotic-specific small molecule, inositol hexakisphosphate (InsP(6)), which is found abundantly in the eukaryotic cytosol. This property allows the CPD to spatially and temporally regulate toxin activation, making it a prime candidate for developing anti-toxin therapeutics. In this review, we summarize recent findings related to defining the regulation of toxin function by the CPD and the development of inhibitors to prevent CPD-mediated activation of bacterial toxins.

  13. The Helicobacter pylori UreI Protein Is Not Involved in Urease Activity but Is Essential for Bacterial Survival In Vivo

    OpenAIRE

    Skouloubris, Stéphane; Thiberge, Jean-Michel; Labigne, Agnès; De Reuse, Hilde

    1998-01-01

    We produced defined isogenic Helicobacter pylori ureI mutants to investigate the function of UreI, the product of one of the genes of the urease cluster. The insertion of a cat cassette had a strong polar effect on the expression of the downstream urease genes, resulting in very weak urease activity. Urease activity, measured in vitro, was normal in a strain in which ureI was almost completely deleted and replaced with a nonpolar cassette. In contrast to previous reports, we thus found that t...

  14. Involvement of a 1-Cys peroxiredoxin in bacterial virulence.

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    Gilberto Hideo Kaihami

    2014-10-01

    Full Text Available The killing of bacterial pathogens by macrophages occurs via the oxidative burst and bacteria have evolved to overcome this challenge and survive, using several virulence and defense strategies, including antioxidant mechanisms. We show here that the 1-Cys peroxiredoxin LsfA from the opportunistic pathogen Pseudomonas aeruginosa is endowed with thiol-dependent peroxidase activity that protects the bacteria from H(2O(2 and that this protein is implicated in pathogenicity. LsfA belongs to the poorly studied Prx6 subfamily of peroxiredoxins. The function of these peroxiredoxins has not been characterized in bacteria, and their contribution to host-pathogen interactions remains unknown. Infection of macrophages with the lsfA mutant strains resulted in higher levels of the cytokine TNF-α production due to the activation of the NF-kB and MAPK pathways, that are partially inhibited by the wild-type P. aeruginosa strain. A redox fluorescent probe was more oxidized in the lsfA mutant-infected macrophages than it was in the macrophages infected with the wild-type strain, suggesting that the oxidative burst was overstimulated in the absence of LsfA. Although no differences in the phagocytosis rates were observed when macrophages were infected with wild-type and mutant bacteria in a gentamicin exclusion assay, a higher number of wild-type bacterial cells was found in the supernatant. This difference was not observed when macrophages were pre-treated with a NADPH oxidase inhibitor, confirming the role of LsfA in the bacterial resistance to ROS generated via NADPH oxidase. In an acute pneumonia model, mice infected with the mutant strains presented higher cytokine release in the lungs and increased activated neutrophil recruitment, with reduced bacterial burden and improved survival rates compared to mice infected with the wild-type bacteria. LsfA is the first bacterial 1-Cys Prx shown to modulate host immune responses and its characterization will allow a

  15. Pneumococcal lipoproteins involved in bacterial fitness, virulence, and immune evasion.

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    Kohler, Sylvia; Voß, Franziska; Gómez Mejia, Alejandro; Brown, Jeremy S; Hammerschmidt, Sven

    2016-11-01

    Streptococcus pneumoniae (pneumococcus) has evolved sophisticated strategies to survive in several niches within the human body either as a harmless commensal or as a serious pathogen causing a variety of diseases. The dynamic interaction between pneumococci and resident host cells during colonization of the upper respiratory tract and at the site of infection is critical for bacterial survival and the development of disease. Pneumococcal lipoproteins are peripherally anchored membrane proteins and have pivotal roles in bacterial fitness including envelope stability, cell division, nutrient acquisition, signal transduction, transport (as substrate-binding proteins of ABC transporter systems), resistance to oxidative stress and antibiotics, and protein folding. In addition, lipoproteins are directly involved in virulence-associated processes such as adhesion, colonization, and persistence through immune evasion. Conversely, lipoproteins are also targets for the host response both as ligands for toll-like receptors and as targets for acquired antibodies. This review summarizes the multifaceted roles of selected pneumococcal lipoproteins and how this knowledge can be exploited to combat pneumococcal infections. © 2016 Federation of European Biochemical Societies.

  16. Inactivating effects of the lactoperoxidase system on bacterial lyases involved in oral malodour production.

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    Nakano, Manabu; Shin, Kouichirou; Wakabayashi, Hiroyuki; Yamauchi, Koji; Abe, Fumiaki; Hironaka, Shouji

    2015-10-01

    The main components of oral malodour have been identified as volatile sulfur compounds (VSCs), including hydrogen sulfide (H(2)S) and methyl mercaptan (CH(3)SH). The lactoperoxidase (LPO) system (consisting of LPO, glucose oxidase, glucose and thiocyanate) was previously shown to exhibit antimicrobial activities against some oral bacteria in vitro and suppressive effects on VSCs in mouth air in a clinical trial. Here, we examined the in vitro effects of the LPO system on the activities of the bacterial lyases involved in the production of VSCs by oral anaerobes. The exposure of crude bacterial extracts of Fusobacterium nucleatum and Porphyromonas gingivalis or purified methionine γ-lyase to the LPO system resulted in the inactivation of their lyase activities through l-cysteine and l-methionine, which was linked to the production of H(2)S and CH(3)SH, respectively. The exposure of living F. nucleatum and P. gingivalis cells to the LPO system resulted in the suppression of cell numbers and lyase activities. The inactivation of the crude bacterial extracts of F. nucleatum and purified methionine γ-lyase by the LPO system was partly recovered by the addition of DTT. Therefore, the LPO system may inactivate bacterial lyases including methionine γ-lyase by reacting with the free cysteine residues of lyases. These results suggested that the LPO system suppresses the production of VSCs not only through its antimicrobial effects, but also by its inactivating effects on the bacterial lyases of F. nucleatum and P. gingivalis.

  17. Bacterial communities involved in soil formation and plant establishment triggered by pyrite bioweathering on arctic moraines.

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    Mapelli, Francesca; Marasco, Ramona; Rizzi, Agostino; Baldi, Franco; Ventura, Stefano; Daffonchio, Daniele; Borin, Sara

    2011-02-01

    In arctic glacier moraines, bioweathering primed by microbial iron oxidizers creates fertility gradients that accelerate soil development and plant establishment. With the aim of investigating the change of bacterial diversity in a pyrite-weathered gradient, we analyzed the composition of the bacterial communities involved in the process by sequencing 16S rRNA gene libraries from different biological soil crusts (BSC). Bacterial communities in three BSC of different morphology, located within 1 m distance downstream a pyritic conglomerate rock, were significantly diverse. The glacier moraine surrounding the weathered site showed wide phylogenetic diversity and high evenness with 15 represented bacterial classes, dominated by Alphaproteobacteria and pioneer Cyanobacteria colonizers. The bioweathered area showed the lowest diversity indexes and only nine bacterial families, largely dominated by Acidobacteriaceae and Acetobacteraceae typical of acidic environments, in accordance with the low pH of the BSC. In the weathered BSC, iron-oxidizing bacteria were cultivated, with counts decreasing along with the increase of distance from the rock, and nutrient release from the rock was revealed by environmental scanning electron microscopy-energy dispersive X-ray analyses. The vegetated area showed the presence of Actinomycetales, Verrucomicrobiales, Gemmatimonadales, Burkholderiales, and Rhizobiales, denoting a bacterial community typical of developed soils and indicating that the lithoid substrate of the bare moraine was here subjected to an accelerated colonization, driven by iron-oxidizing activity.

  18. Promoting Active Involvement in Classrooms

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    Conderman, Greg; Bresnahan, Val; Hedin, Laura

    2012-01-01

    This article presents a rationale for using active involvement techniques, describes large- and small-group methods based on their documented effectiveness and applicability to K-12 classrooms, and illustrates their use. These approaches include ways of engaging students in large groups (e.g., unison responses, response cards, dry-erase boards,…

  19. Forces involved in bacterial adhesion to hydrophilic and hydrophobic surfaces

    NARCIS (Netherlands)

    Boks, N.P.; Norde, W.; Meil, H.C.; Busscher, H.J.

    2008-01-01

    Using a parallel-plate flow chamber, the hydrodynamic shear forces to prevent bacterial adhesion (F-prev) and to detach adhering bacteria (F-det) were evaluated for hydrophilic glass, hydrophobic, dimethyldichlorosilane (DDS)-coated glass and six different bacterial strains, in order to test the

  20. Forces involved in bacterial adhesion to hydrophilic and hydrophobic surfaces

    NARCIS (Netherlands)

    Boks, Niels P.; Norde, Willem; van der Mei, Henny C.; Busscher, Henk J.

    2008-01-01

    Using a parallel-plate flow chamber, the hydrodynamic shear forces to prevent bacterial adhesion (F(prev)) and to detach adhering bacteria (F(det)) were evaluated for hydrophilic glass, hydrophobic, dimethyldichlorosilane (DDS)-coated glass and six different bacterial strains, in order to test the

  1. Forces involved in bacterial adhesion to hydrophilic and hydrophobic surfaces

    NARCIS (Netherlands)

    Boks, N.P.; Norde, W.; Meil, H.C.; Busscher, H.J.

    2008-01-01

    Using a parallel-plate flow chamber, the hydrodynamic shear forces to prevent bacterial adhesion (F-prev) and to detach adhering bacteria (F-det) were evaluated for hydrophilic glass, hydrophobic, dimethyldichlorosilane (DDS)-coated glass and six different bacterial strains, in order to test the fol

  2. Forces involved in bacterial adhesion to hydrophilic and hydrophobic surfaces

    NARCIS (Netherlands)

    Boks, Niels P.; Norde, Willem; van der Mei, Henny C.; Busscher, Henk J.

    2008-01-01

    Using a parallel-plate flow chamber, the hydrodynamic shear forces to prevent bacterial adhesion (F(prev)) and to detach adhering bacteria (F(det)) were evaluated for hydrophilic glass, hydrophobic, dimethyldichlorosilane (DDS)-coated glass and six different bacterial strains, in order to test the f

  3. Modeling interdisciplinary activities involving Mathematics

    DEFF Research Database (Denmark)

    Iversen, Steffen Møllegaard

    2006-01-01

    In this paper a didactical model is presented. The goal of the model is to work as a didactical tool, or conceptual frame, for developing, carrying through and evaluating interdisciplinary activities involving the subject of mathematics and philosophy in the high schools. Through the terms...... domains (Michelsen, 2001, 2005a, 2005b). Furthermore the theoretical description rest on a series of qualitative interviews with teachers from the Danish high school (grades 9-11) conducted recently. The special case of concrete interdisciplinary activities between mathematics and philosophy is also...

  4. A host defense mechanism involving CFTR-mediated bicarbonate secretion in bacterial prostatitis.

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    Chen Xie

    Full Text Available BACKGROUND: Prostatitis is associated with a characteristic increase in prostatic fluid pH; however, the underlying mechanism and its physiological significance have not been elucidated. METHODOLOGY/PRINCIPAL FINDINGS: In this study a primary culture of rat prostatic epithelial cells and a rat prostatitis model were used. Here we reported the involvement of CFTR, a cAMP-activated anion channel conducting both Cl(- and HCO(3(-, in mediating prostate HCO(3(- secretion and its possible role in bacterial killing. Upon Escherichia coli (E. coli-LPS challenge, the expression of CFTR and carbonic anhydrase II (CA II, along with several pro-inflammatory cytokines was up-regulated in the primary culture of rat prostate epithelial cells. Inhibiting CFTR function in vitro or in vivo resulted in reduced bacterial killing by prostate epithelial cells or the prostate. High HCO(3(- content (>50 mM, rather than alkaline pH, was found to be responsible for bacterial killing. The direct action of HCO(3(- on bacterial killing was confirmed by its ability to increase cAMP production and suppress bacterial initiation factors in E. coli. The relevance of the CFTR-mediated HCO(3(- secretion in humans was demonstrated by the upregulated expression of CFTR and CAII in human prostatitis tissues. CONCLUSIONS/SIGNIFICANCE: The CFTR and its mediated HCO(3(- secretion may be up-regulated in prostatitis as a host defense mechanism.

  5. Modeling interdisciplinary activities involving Mathematics

    DEFF Research Database (Denmark)

    Iversen, Steffen Møllegaard

    2006-01-01

    In this paper a didactical model is presented. The goal of the model is to work as a didactical tool, or conceptual frame, for developing, carrying through and evaluating interdisciplinary activities involving the subject of mathematics and philosophy in the high schools. Through the terms...... of Horizontal Intertwining, Vertical Structuring and Horizontal Propagation the model consists of three phases, each considering different aspects of the nature of interdisciplinary activities. The theoretical modelling is inspired by work which focuses on the students abilities to concept formation in expanded...... domains (Michelsen, 2001, 2005a, 2005b). Furthermore the theoretical description rest on a series of qualitative interviews with teachers from the Danish high school (grades 9-11) conducted recently. The special case of concrete interdisciplinary activities between mathematics and philosophy is also...

  6. ANTIMICROBIAL ACTIVITY OF LACTIC ACID BACTERIAL ISOLATES

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    Utkarsha S. Shivsharan

    2013-08-01

    Full Text Available Micro-organisms have tendency to produce antimicrobial substances which show biological activity against other kind of micro-organisms. This phenomenon of bacterial antagonism is observed in lactic acid bacteria with competitive advantages. The lactic acid bacteria are commonly present in many fermented products, fruits and milk products. The variety of antimicrobial substances produced by lactic acid bacteria showing good inhibition capacity include production of lactic acid, acetic acid, hydrogen peroxide, carbon dioxide, diacetyl and bacteriocin. Bacteriocins produced by lactic acid bacteria are the subject of intense research because of their antimicrobial activity against food born bacteria such as Listeria monocytogenes, staphylococcus aureus, Bacillus cereus, Clostridium botulinum and several others .Bacteriocins may be bacteriostatic or bactericidal with narrow or broad range of activity. The main of the study was to study the antimicrobial activity of such lactic acid bacterial isolates.

  7. Isolation and Characterization of Gut Bacterial Proteases Involved in Inducing Pathogenicity of Bacillus thuringiensis Toxin in Cotton Bollworm, Helicoverpa armigera

    Science.gov (United States)

    Regode, Visweshwar; Kuruba, Sreeramulu; Mohammad, Akbar S.; Sharma, Hari C.

    2016-01-01

    Bacillus thuringiensis toxin proteins are deployed in transgenic plants for pest management. The present studies were aimed at characterization of gut bacterial proteases involved in activation of inactive Cry1Ac protoxin (pro-Cry1Ac) to active toxin in Helicoverpa armigera. Bacterial strains were isolated from H. armigera midgut and screened for their proteolytic activation toward pro-Cry1Ac. Among 12 gut bacterial isolates seven isolates showed proteolytic activity, and proteases from three isolates (IVS1, IVS2, and IVS3) were found to be involved in the proteolytic conversion of pro-Cry1Ac into active toxin. The proteases from IVS1, IVS2, and IVS3 isolates were purified to 11.90-, 15.50-, and 17.20-fold, respectively. The optimum pH and temperature for gut bacterial protease activity was 8.0 and 40°C. Maximum inhibition of total proteolytic activity was exerted by phenylmethane sulfonyl fluoride followed by EDTA. Fluorescence zymography revealed that proteases from IVS1, IVS2, and IVS3 were chymotrypsin-like and showing protease band at ~15, 65, and 15 kDa, respectively. Active Cry1Ac formed from processing pro-Cry1Ac by gut bacterial proteases exhibited toxicity toward H. armigera. The gut bacterial isolates IVS1, IVS2, and IVS3 showed homology with B. thuringiensis (CP003763.1), Vibrio fischeri (CP000020.2), and Escherichia coli (CP011342.1), respectively. Proteases produced by midgut bacteria are involved in proteolytic processing of B. thuringiensis protoxin and play a major role in inducing pathogenicity of B. thuringiensis toxins in H. armigera. PMID:27766093

  8. Isolation and characterization of gut bacterial proteases involved in inducing pathogenicity of Bacillus thuringiensis toxin in cotton bollworm, Helicoverpa armigera

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    Visweshwar Regode

    2016-10-01

    Full Text Available Bacillus thuringiensis (Bt toxin proteins are deployed in transgenic plants for pest management. The present studies were aimed at characterization of gut bacterial proteases involved in activation of inactive Cry1Ac protoxin (pro-Cry1Ac to active toxin in Helicoverpa armigera. Bacterial strains were isolated from H. armigera midgut and screened for their proteolytic activation towards pro-Cry1Ac. Among twelve gut bacterial isolates seven isolates showed proteolytic activity, and proteases from three isolates (IVS1, IVS2 and IVS3 were found to be involved in the proteolytic conversion of pro-Cry1Ac into active toxin. The proteases from IVS1, IVS2 and IVS3 isolates were purified to 11.90-, 15.50- and 17.20-fold, respectively. The optimum pH and temperature for gut bacterial protease activity was 8.0 and 40 oC. Maximum inhibition of total proteolytic activity was exerted by PMSF followed by EDTA. Fluorescence zymography revealed that proteases from IVS1, IVS2, and IVS3 were chymotrypsin-like and showing protease band at ~15, 65 and 15 kDa, respectively. Active Cry1Ac formed from processing pro-Cry1Ac by gut bacterial proteases exhibited toxicity towards H. armigera. The gut bacterial isolates IVS1, IVS2 and IVS3 showed homology with Bacillus thuringiensis (CP003763.1, Vibrio fischeri (CP000020.2 and Escherichia coli (CP011342.1, respectively. Proteases produced by midgut bacteria are involved in proteolytic processing of Bt protoxin and play a major role in inducing pathogenicity of Bt toxins in H. armigera.

  9. Forces involved in bacterial adhesion to hydrophilic and hydrophobic surfaces.

    Science.gov (United States)

    Boks, Niels P; Norde, Willem; van der Mei, Henny C; Busscher, Henk J

    2008-10-01

    Using a parallel-plate flow chamber, the hydrodynamic shear forces to prevent bacterial adhesion (F(prev)) and to detach adhering bacteria (F(det)) were evaluated for hydrophilic glass, hydrophobic, dimethyldichlorosilane (DDS)-coated glass and six different bacterial strains, in order to test the following three hypotheses. 1. A strong hydrodynamic shear force to prevent adhesion relates to a strong hydrodynamic shear force to detach an adhering organism. 2. A weak hydrodynamic shear force to detach adhering bacteria implies that more bacteria will be stimulated to detach by passing an air-liquid interface (an air bubble) through the flow chamber. 3. DLVO (Derjaguin, Landau, Verwey, Overbeek) interactions determine the characteristic hydrodynamic shear forces to prevent adhesion and to detach adhering micro-organisms as well as the detachment induced by a passing air-liquid interface. F(prev) varied from 0.03 to 0.70 pN, while F(det) varied from 0.31 to over 19.64 pN, suggesting that after initial contact, strengthening of the bond occurs. Generally, it was more difficult to detach bacteria from DDS-coated glass than from hydrophilic glass, which was confirmed by air bubble detachment studies. Calculated attractive forces based on the DLVO theory (F(DLVO)) towards the secondary interaction minimum were higher on glass than on DDS-coated glass. In general, all three hypotheses had to be rejected, showing that it is important to distinguish between forces acting parallel (hydrodynamic shear) and perpendicular (DLVO, air-liquid interface passages) to the substratum surface.

  10. Bacterial communities involved in sulfur transformations in wastewater treatment plants.

    Science.gov (United States)

    Meyer, Daniel Derrossi; de Andrade, Pedro Avelino Maia; Durrer, Ademir; Andreote, Fernando Dini; Corção, Gertrudes; Brandelli, Adriano

    2016-12-01

    The main sulfate-reducing (SRB) and sulfur-oxidizing bacteria (SOB) in six wastewater treatment plants (WWTPs) located at southern Brazil were described based on high-throughput sequencing of the 16S rDNA. Specific taxa of SRB and SOB were correlated with some abiotic factors, such as the source of the wastewater, oxygen content, sample type, and physical chemical attributes of these WWTPs. When the 22 families of SRB and SOB were clustered together, the samples presented a striking distribution, demonstrating grouping patterns according to the sample type. For SOB, the most abundant families were Spirochaetaceae, Chromatiaceae, Helicobacteriaceae, Rhodospirillaceae, and Neisseriaceae, whereas, for SRB, were Syntrophaceae, Desulfobacteraceae, Nitrospiraceae, and Desulfovibriaceae. The structure and composition of the major families related to the sulfur cycle were also influenced by six chemical attributes (sulfur, potassium, zinc, manganese, phosphorus, and nitrogen). Sulfur was the chemical attribute that most influenced the variation of bacterial communities in the WWTPs (λ = 0.14, p = 0.008). The OTUs affiliated to Syntrophus showed the highest response to the increase of total sulfur. All these findings can contribute to improve the understanding in relation to the sulfur-oxidizing and sulfate-reducing communities in WWTPs aiming to reduce H2S emissions.

  11. Involvement of the cell-specific pigment genes pks and sult in bacterial defense response of sea urchins Strongylocentrotus intermedius.

    Science.gov (United States)

    Kiselev, Konstantin V; Ageenko, Natalya V; Kurilenko, Valeria V

    2013-03-26

    Bacterial infections are one of the most important problems in mass aquaculture, causing the loss of millions of juvenile organisms. We isolated 22 bacterial strains from the cavity fluid of the sea urchin Strongylocentrotus pallidus and used phylogenetic analysis based on 16S rRNA gene sequences to separate the bacterial strains into 9 genera (Aliivibrio, Bizionia, Colwellia, Olleya, Paenibacillus, Photobacterium, Pseudoalteromonas, Shewanella, and Vibrio). Incubating Strongylocentrotus intermedius larvae with a strain from each of the 9 bacterial genera, we investigated the viability of the larvae, the amount of pigment cells, and the level of polyketide synthase (pks) and sulfotransferase (sult) gene expression. Results of the assay on sea urchin development showed that all bacterial strains, except Pseudoalteromonas and Bizionia, suppressed sea urchin development (resulting in retardation of the embryos' development with cellular disorders) and reduced cell viability. We found that pks expression in the sea urchin larvae after incubation with the bacteria of 9 tested genera was significantly increased, while the sult expression was increased only after the treatment with Pseudoalteromonas and Shewanella. Shikimic acid, which is known to activate the biosynthesis of naphthoquinone pigments, increased the tolerance of the sea urchin embryos to the bacteria. In conclusion, we show that the cell-specific pigment genes pks and sult are involved in the bacterial defense response of sea urchins.

  12. Bacterial oxidation activity in heap leaching

    Institute of Scientific and Technical Information of China (English)

    柳建设; 夏海波; 王兆慧; 胡岳华

    2004-01-01

    Bioleaching of sulfide minerals by bacteria, mainly Thiobacillus ferrooxidans (T. f. ) and Thiobacillus thiooxidans, plays an important role in hydrometallurgy because of its economic and environmental attractions. The surveys of production process and the bacterial oxidation activity in the heap bioleaching were investigated. The results show that pH value is high, bacteria biomass and ferric concentration are low, generation time (above 7.13 h)is long in leachate, and less bacteria are adsorbed on the ores. The bacteria in the leachate exposing on the surface and connecting with mineral, have much faster oxidation rate of Fe( Ⅱ ) and shorter generation time, compared with those which are in the reservoir for a long time. There is diversity for oxidation activity of Fe( Ⅱ ), while there is no diversity for oxidation of sulfur. So it is advisable to add sulfuric acid to degrade pH value to 2.0, add nutrients and shorten recycling time of leachate, so as to enhance bacteria concentration of leachate and the leaching efficiency.

  13. A Small Group Activity About Bacterial Regulation And Complementation

    Directory of Open Access Journals (Sweden)

    Susan M. Merkel

    2010-11-01

    Full Text Available As teachers, we well understand the need for activities that help develop critical-thinking skills in microbiology. In our experience, one concept that students have difficulty understanding is transcriptional regulation of bacterial genes. To help with this, we developed and evaluated a paper-based activity to help students understand and apply the concepts of bacterial transcriptional regulation. While we don't identify it as such, we use a complementation experiment to assess student understanding of how regulation changes when new DNA is introduced. In Part 1 of this activity, students complete an open book, take-home assignment that asks them to define common terminology related to regulation, and draw the regulatory components of different scenarios involving positive and negative regulation. In Part 2, students work in small groups of 3-4 to depict the regulatory components for a different scenario. They are asked to explain the results of a complementation experiment based on this scenario. They then predict the results of a slightly different experiment. Students who completed the Regulation Activity did significantly better on post-test questions related to regulation, compared to pre-test questions.

  14. Supporting Active User Involvment in Prototyping

    DEFF Research Database (Denmark)

    Grønbæk, Kaj

    1990-01-01

    in the development process. But prototyping does not automatically imply active user involvement! Thus a cooperative prototyping approach aiming at involving users actively and creatively in system design is proposed in this paper. The key point of the approach is to involve users in activities that closely couple......The term prototyping has in recent years become a buzzword in both research and practice of system design due to a number of claimed advantages of prototyping techniques over traditional specification techniques. In particular it is often stated that prototyping facilitates the users' involvement...... development of prototypes to early evaluation of prototypes in envisioned use situations. Having users involved in such activities creates new requirements for tool support. Tools that support direct manipulation of prototypes and simulation of behaviour have shown promise for cooperative prototyping...

  15. Involvement of sulfidogenic bacteria in iron corrosion; Role des bacteries sulfurogenes dans la corrosion du fer

    Energy Technology Data Exchange (ETDEWEB)

    Marchal, R. [Institut Francais du Petrole (IFP), 92 - Rueil-Malmaison (France)

    1999-07-01

    The involvement of sulfidogenic bacteria in the corrosion of carbon steel is reviewed. After a brief description of some recent cases drawn from the petroleum industry, the physiology of the sulfidogenic bacteria which plays the most important role in the mechanism of anaerobic bacterial corrosion is examined The involvement of H{sub 2}S-producing bacteria to the bio-film formation is a prerequisite for bio-corrosion. The hypothetical mechanisms described in the literature are reviewed Regardless of the physicochemical role played by iron sulfides, which have been shown to be non-covering and to have good properties of electric conductivity, the acidification arising from cellular metabolism has been found to be an important parameter, not only in terms of electrochemistry but also in terms of microbial growth. Metabolic acidification probably explains the ferrous ion supply to the microorganism in an environment with a high level of sulfide ions and finally the persistence of the microbial H{sub 2}S-producing activity. (author)

  16. Bacterial populations and processes involved in acetate and propionate consumption in anoxic brackish sediment

    NARCIS (Netherlands)

    Boschker, H.T.S.; De Graaf, W.; Köster, M.; Meyer-Reil, L.A.; Cappenberg, T.E.

    2001-01-01

    Bacterial populations and pathways involved in acetate and propionate consumption were studied in anoxic brackish sediment from the Grosser Jasmunder Bodden, German Baltic Sea. Uptake of acetate and propionate from the porewater was studied using stable carbon isotope-labeled compounds. Labeled acet

  17. Pupils' involvement in ecological activities in school

    Directory of Open Access Journals (Sweden)

    Stanišić Jelena

    2009-01-01

    Full Text Available Ecological education gains an increasing importance in the moment when ecological crisis acquires increasingly larger proportions. Education is one of the most powerful social means in fighting problems and challenges of the future. This paper presents the results of the research referring to pupils' attitudes with respect to the activities they prefer to be involved in, the independent variables their readiness for involvement depends on, as well as the relation between the knowledge possessed by pupils and their readiness to be involved in ecological activities. Research was conducted on the sample of 284 pupils in the eighth grade of primary school in urban and rural area and polluted and unpolluted environment. The results indicate that pupils find more interesting the activities taking place in nature, those where they are immediate participants and those where they have a subjective feeling that they are doing something to protect the environment. Besides, the results show that girls from both samples and pupils from rural area are more ready to get involved in ecological activities. Living in polluted or unpolluted environment is not a statistically significant variable which would influence the readiness of pupils to get involved in these activities. As the most interesting result of this research, we consider the finding that a higher level of pupils' ecological knowledge and living in polluted environment do not guarantee higher readiness of pupils to get involved in the activities of environment protection.

  18. Involvement of bacterial migration in the development of complex multicellular structures in Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Klausen, Mikkel; Aaes-Jorgensen, A.; Molin, Søren

    2003-01-01

    development, we have performed an investigation with time-lapse confocal laser scanning microscopy of biofilms formed by various combinations of colour-coded P. aeruginosa wild type and motility mutants. We show that mushroom-shaped multicellular structures in P. aeruginosa biofilms can form in a sequential...... process involving a non-motile bacterial subpopulation and a migrating bacterial subpopulation. The non-motile bacteria form the mushroom stalks by growth in certain foci of the biofilm. The migrating bacteria form the mushroom caps by climbing the stalks and aggregating on the tops in a process which...

  19. Involvement of bacterial migration in the development of complex multicellular structures in Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Klausen, Mikkel; Aaes-Jorgensen, A.; Molin, Søren;

    2003-01-01

    development, we have performed an investigation with time-lapse confocal laser scanning microscopy of biofilms formed by various combinations of colour-coded P. aeruginosa wild type and motility mutants. We show that mushroom-shaped multicellular structures in P. aeruginosa biofilms can form in a sequential...... process involving a non-motile bacterial subpopulation and a migrating bacterial subpopulation. The non-motile bacteria form the mushroom stalks by growth in certain foci of the biofilm. The migrating bacteria form the mushroom caps by climbing the stalks and aggregating on the tops in a process which...

  20. Bacterial contamination in hotel rooms during the cleaning activity

    OpenAIRE

    Monteiro, ANA; Cabo Verde, Sandra; Carolino, Elisabete

    2016-01-01

    Introduction - Some studies point to human activities as one of the responsible for most bacterial concentration. However, there is no information regarding bacteria contamination in hotel room during the cleaning activity. Aim of the study - This study aims to assess and characterize the occupational exposure of bacterial contamination in hotel rooms, more precisely in a room with carpet floor and another room without carpet, during the cheaning activity.

  1. Learning models of activities involving interacting objects

    DEFF Research Database (Denmark)

    Manfredotti, Cristina; Pedersen, Kim Steenstrup; Hamilton, Howard J.;

    2013-01-01

    We propose the LEMAIO multi-layer framework, which makes use of hierarchical abstraction to learn models for activities involving multiple interacting objects from time sequences of data concerning the individual objects. Experiments in the sea navigation domain yielded learned models that were...... then successfully applied to activity recognition, activity simulation and multi-target tracking. Our method compares favourably with respect to previously reported results using Hidden Markov Models and Relational Particle Filtering....

  2. Cooperativity of peptidoglycan synthases active in bacterial cell elongation.

    NARCIS (Netherlands)

    Banzhaf, M.; van den Berg van Saparoea, B.; Terrak, M.; Fraipont, C.; Egan, A.; Philippe, J.; Zapun, A.; Breukink, E.; Nguyen-Distèche, M.; den Blaauwen, T.; Vollmer, W.

    2012-01-01

    Growth of the bacterial cell wall peptidoglycan sacculus requires the co-ordinated activities of peptidoglycan synthases, hydrolases and cell morphogenesis proteins, but the details of these interactions are largely unknown. We now show that the Escherichia coli peptidoglycan

  3. Fluorogenic Peptide Substrate for Quantification of Bacterial Enzyme Activities

    National Research Council Canada - National Science Library

    Ismail H Al-abdullah; Karine Bagramyan; Shiela Bilbao; Meirigeng Qi; Markus Kalkum

    2017-01-01

    A novel peptide substrate (A G G P L G P P G P G G) was developed for quantifying the activities of bacterial enzymes using a highly sensitive Fluorescence Resonance Energy Transfer (FRET) based assay...

  4. Supporting Active User Involvment in Prototyping

    DEFF Research Database (Denmark)

    Grønbæk, Kaj

    1990-01-01

    development of prototypes to early evaluation of prototypes in envisioned use situations. Having users involved in such activities creates new requirements for tool support. Tools that support direct manipulation of prototypes and simulation of behaviour have shown promise for cooperative prototyping...... activities. Examples of such tools are given and the ways that they support cooperative prototyping within various use domains are discussed.......The term prototyping has in recent years become a buzzword in both research and practice of system design due to a number of claimed advantages of prototyping techniques over traditional specification techniques. In particular it is often stated that prototyping facilitates the users' involvement...

  5. Learning models of activities involving interacting objects

    DEFF Research Database (Denmark)

    Manfredotti, Cristina; Pedersen, Kim Steenstrup; Hamilton, Howard J.;

    2013-01-01

    We propose the LEMAIO multi-layer framework, which makes use of hierarchical abstraction to learn models for activities involving multiple interacting objects from time sequences of data concerning the individual objects. Experiments in the sea navigation domain yielded learned models that were...

  6. Learning models of activities involving interacting objects

    DEFF Research Database (Denmark)

    Manfredotti, Cristina; Pedersen, Kim Steenstrup; Hamilton, Howard J.

    2013-01-01

    We propose the LEMAIO multi-layer framework, which makes use of hierarchical abstraction to learn models for activities involving multiple interacting objects from time sequences of data concerning the individual objects. Experiments in the sea navigation domain yielded learned models that were t...

  7. Rho GTPase-activating bacterial toxins: from bacterial virulence regulation to eukaryotic cell biology.

    Science.gov (United States)

    Lemonnier, Marc; Landraud, Luce; Lemichez, Emmanuel

    2007-09-01

    Studies on the interactions of bacterial pathogens with their host have provided an invaluable source of information on the major functions of eukaryotic and prokaryotic cell biology. In addition, this expanding field of research, known as cellular microbiology, has revealed fascinating examples of trans-kingdom functional interplay. Bacterial factors actually exploit eukaryotic cell machineries using refined molecular strategies to promote invasion and proliferation within their host. Here, we review a family of bacterial toxins that modulate their activity in eukaryotic cells by activating Rho GTPases and exploiting the ubiquitin/proteasome machineries. This family, found in human and animal pathogenic Gram-negative bacteria, encompasses the cytotoxic necrotizing factors (CNFs) from Escherichia coli and Yersinia species as well as dermonecrotic toxins from Bordetella species. We survey the genetics, biochemistry, molecular and cellular biology of these bacterial factors from the standpoint of the CNF1 toxin, the paradigm of Rho GTPase-activating toxins produced by urinary tract infections causing pathogenic Escherichia coli. Because it reveals important connections between bacterial invasion and the host inflammatory response, the mode of action of CNF1 and its related Rho GTPase-targetting toxins addresses major issues of basic and medical research and constitutes a privileged experimental model for host-pathogen interaction.

  8. Delayed bactericidal response of Mycobacterium tuberculosis to bedaquiline involves remodelling of bacterial metabolism

    DEFF Research Database (Denmark)

    Koul, A.; Vranckx, L.; Dhar, N.;

    2014-01-01

    microfluidic devices and time-lapse microscopy of Mycobacterium tuberculosis, we confirm the absence of significant bacteriolytic activity during the first 3-4 days of exposure to BDQ. BDQ-induced inhibition of ATP synthesis leads to bacteriostasis within hours after drug addition. Transcriptional......Bedaquiline (BDQ), an ATP synthase inhibitor, is the first drug to be approved for treatment of multidrug-resistant tuberculosis in decades. Though BDQ has shown excellent efficacy in clinical trials, its early bactericidal activity during the first week of chemotherapy is minimal. Here, using...... and proteomic analyses reveal that M. tuberculosis responds to BDQ by induction of the dormancy regulon and activation of ATP-generating pathways, thereby maintaining bacterial viability during initial drug exposure. BDQ-induced bacterial killing is significantly enhanced when the mycobacteria are grown on non...

  9. Particle surface area and bacterial activity in recirculating aquaculture systems

    DEFF Research Database (Denmark)

    Pedersen, Per Bovbjerg; von Ahnen, Mathis; Fernandes, Paulo

    2017-01-01

    Suspended particles in recirculating aquaculture systems (RAS) provide surface area that can be colonized by bacteria. More particles accumulate as the intensity of recirculation increases thus potentially increasing the bacterial carrying capacity of the systems. Applying a recent, rapid, culture......-independent fluorometric detection method (Bactiquant®) for measuring bacterial activity, the current study explored the relationship between total particle surface area (TSA, derived from the size distribution of particles >5 μm) and bacterial activity in freshwater RAS operated at increasing intensity of recirculation......-up water; corresponding to 0.32 m3 make-up water kg−1 feed). This was likely due to the accumulation of dissolved nutrients sustaining free-living bacterial populations, and/or accumulation of suspended colloids and fine particles less than 5 μm in diameter, which were not characterized in the study...

  10. A type VI secretion system is involved in Pseudomonas fluorescens bacterial competition.

    Science.gov (United States)

    Decoin, Victorien; Barbey, Corinne; Bergeau, Dorian; Latour, Xavier; Feuilloley, Marc G J; Orange, Nicole; Merieau, Annabelle

    2014-01-01

    Protein secretion systems are crucial mediators of bacterial interactions with other organisms. Among them, the type VI secretion system (T6SS) is widespread in Gram-negative bacteria and appears to inject toxins into competitor bacteria and/or eukaryotic cells. Major human pathogens, such as Vibrio cholerae, Burkholderia and Pseudomonas aeruginosa, express T6SSs. Bacteria prevent self-intoxication by their own T6SS toxins by producing immunity proteins, which interact with the cognate toxins. We describe here an environmental P. fluorescens strain, MFE01, displaying an uncommon oversecretion of Hcp (hemolysin-coregulated protein) and VgrG (valine-glycine repeat protein G) into the culture medium. These proteins are characteristic components of a functional T6SS. The aim of this study was to attribute a role to this energy-consuming overexpression of the T6SS. The genome of MFE01 contains at least two hcp genes (hcp1 and hcp2), suggesting that there may be two putative T6SS clusters. Phenotypic studies have shown that MFE01 is avirulent against various eukaryotic cell models (amebas, plant or animal cell models), but has antibacterial activity against a wide range of competitor bacteria, including rhizobacteria and clinical bacteria. Depending on the prey cell, mutagenesis of the hcp2 gene in MFE01 abolishes or reduces this antibacterial killing activity. Moreover, the introduction of T6SS immunity proteins from S. marcescens, which is not killed by MFE01, protects E. coli against MFE01 killing. These findings suggest that the protein encoded by hcp2 is involved in the killing activity of MFE01 mediated by effectors of the T6SS targeting the peptidoglycan of Gram-negative bacteria. Our results indicate that MFE01 can protect potato tubers against Pectobacterium atrosepticum, which causes tuber soft rot. Pseudomonas fluorescens is often described as a major PGPR (plant growth-promoting rhizobacterium), and our results suggest that there may be a connection between

  11. A type VI secretion system is involved in Pseudomonas fluorescens bacterial competition.

    Directory of Open Access Journals (Sweden)

    Victorien Decoin

    Full Text Available Protein secretion systems are crucial mediators of bacterial interactions with other organisms. Among them, the type VI secretion system (T6SS is widespread in Gram-negative bacteria and appears to inject toxins into competitor bacteria and/or eukaryotic cells. Major human pathogens, such as Vibrio cholerae, Burkholderia and Pseudomonas aeruginosa, express T6SSs. Bacteria prevent self-intoxication by their own T6SS toxins by producing immunity proteins, which interact with the cognate toxins. We describe here an environmental P. fluorescens strain, MFE01, displaying an uncommon oversecretion of Hcp (hemolysin-coregulated protein and VgrG (valine-glycine repeat protein G into the culture medium. These proteins are characteristic components of a functional T6SS. The aim of this study was to attribute a role to this energy-consuming overexpression of the T6SS. The genome of MFE01 contains at least two hcp genes (hcp1 and hcp2, suggesting that there may be two putative T6SS clusters. Phenotypic studies have shown that MFE01 is avirulent against various eukaryotic cell models (amebas, plant or animal cell models, but has antibacterial activity against a wide range of competitor bacteria, including rhizobacteria and clinical bacteria. Depending on the prey cell, mutagenesis of the hcp2 gene in MFE01 abolishes or reduces this antibacterial killing activity. Moreover, the introduction of T6SS immunity proteins from S. marcescens, which is not killed by MFE01, protects E. coli against MFE01 killing. These findings suggest that the protein encoded by hcp2 is involved in the killing activity of MFE01 mediated by effectors of the T6SS targeting the peptidoglycan of Gram-negative bacteria. Our results indicate that MFE01 can protect potato tubers against Pectobacterium atrosepticum, which causes tuber soft rot. Pseudomonas fluorescens is often described as a major PGPR (plant growth-promoting rhizobacterium, and our results suggest that there may be a

  12. Involvement of Pacific oyster CgPGRP-S1S in bacterial recognition, agglutination and granulocyte degranulation.

    Science.gov (United States)

    Iizuka, Masao; Nagasaki, Toshihiro; Takahashi, Keisuke G; Osada, Makoto; Itoh, Naoki

    2014-03-01

    Peptidoglycan recognition protein (PGRP) recognizes invading bacteria through their peptidoglycans (PGN), a component of the bacterial cell wall. Insect PGRPs contribute to effective immune systems as inducers of other host defense responses, while this function has not been reported from PGRP of bivalves. In this study, recombinant CgPGRP-S1S (rCgPGRP-S1S), produced in the mantle and the gill, was synthesized and used to elucidate the immunological function of CgPGRP-S1S. rCgPGRP-S1S bound specifically to DAP-type PGN and to Escherichia coli cells, but not to other DAP-type PGN-containing bacterial species, Vibrio anguillarum, or Bacillus subtilis. Antibacterial activity was not detected, but E. coli cells were agglutinated. Moreover, in addition to these direct interactions with bacterial cells, rCgPGRP-S1S induced secretion of granular contents by hemocyte degranulation. Taken together, these results suggest for the first time that a PGRP of bivalves is, just as in insects, involved in host defense, not only by direct interaction with bacteria, but also by triggering other defense pathways.

  13. Isolation of biologically active nanomaterial (inclusion bodies from bacterial cells

    Directory of Open Access Journals (Sweden)

    Peternel Špela

    2010-09-01

    Full Text Available Abstract Background In recent years bacterial inclusion bodies (IBs were recognised as highly pure deposits of active proteins inside bacterial cells. Such active nanoparticles are very interesting for further downstream protein isolation, as well as for many other applications in nanomedicine, cosmetic, chemical and pharmaceutical industry. To prepare large quantities of a high quality product, the whole bioprocess has to be optimised. This includes not only the cultivation of the bacterial culture, but also the isolation step itself, which can be of critical importance for the production process. To determine the most appropriate method for the isolation of biologically active nanoparticles, three methods for bacterial cell disruption were analyzed. Results In this study, enzymatic lysis and two mechanical methods, high-pressure homogenization and sonication, were compared. During enzymatic lysis the enzyme lysozyme was found to attach to the surface of IBs, and it could not be removed by simple washing. As this represents an additional impurity in the engineered nanoparticles, we concluded that enzymatic lysis is not the most suitable method for IBs isolation. During sonication proteins are released (lost from the surface of IBs and thus the surface of IBs appears more porous when compared to the other two methods. We also found that the acoustic output power needed to isolate the IBs from bacterial cells actually damages proteins structures, thereby causing a reduction in biological activity. High-pressure homogenization also caused some damage to IBs, however the protein loss from the IBs was negligible. Furthermore, homogenization had no side-effects on protein biological activity. Conclusions The study shows that among the three methods tested, homogenization is the most appropriate method for the isolation of active nanoparticles from bacterial cells.

  14. Bacterial Diversity of Active Sludge in Wastewater Treatment Plant

    Science.gov (United States)

    Jiang, Xin; Ma, Mingchao; Li, Jun; Lu, Anhuai; Zhong, Zuoshen

    A bacterial 16S rDNA gene clone library was constructed to analyze the bacterial diversity of active sludge in Gaobeidian Wastewater Treatment Plant, Beijing. The results indicated that the bacterial diversity of active sludge was very high, and the clones could be divided into 5 different groups. The dominant bacterial community was proteobacteria, which accounted for 76.7%. The dominant succession of bacterial community were as follows: the β-proteobacteria (39.8%), the uncultured bacteria (22.33%), the γ-proteobacteria (20.15%), the α-proteobacteria (6.79%), and the σ-proteobacteria (4.85%). Nitrosomonas-like and Nitrospira-like bacteria, such as Nitrosomonas sp. (1.94%) and uncultured Nitrospirae bacterium (11.65%) were also detected, which have played important roles in ammonia and nitrite oxidisers in the system. However, they were only a little amount because of their slow growth and less competitive advantage than heterotrophic bacteria. Denitrifying bacteria like Thauera sp. was at a high percentage, which implies a strong denitrification ability; Roseomonas sp. was also detected in the clone library, which could be related to the degradation of organophosphorus pesticide.

  15. A dynamin-like protein involved in bacterial cell membrane surveillance under environmental stress.

    Science.gov (United States)

    Sawant, Prachi; Eissenberger, Kristina; Karier, Laurence; Mascher, Thorsten; Bramkamp, Marc

    2016-09-01

    In ever-changing natural environments, bacteria are continuously challenged with numerous biotic and abiotic stresses. Accordingly, they have evolved both specific and more general mechanisms to counteract stress-induced damage and ensure survival. In the soil habitat of Bacillus subtilis, peptide antibiotics and bacteriophages are among the primary stressors that affect the integrity of the cytoplasmic membrane. Dynamin-like proteins (DLPs) play a major role in eukaryotic membrane re-modelling processes, including antiviral activities, but the function of the corresponding bacterial homologues was so far poorly understood. Here, we report on the protective function of a bacterial DLP, DynA from B. subtilis. We provide evidence that DynA plays an important role in a membrane surveillance system that counteracts membrane pore formation provoked by antibiotics and phages. In unstressed cells, DynA is a highly dynamic membrane-associated protein. Upon membrane damage, DynA localizes into large and static assemblies, where DynA acts locally to counteract stress-induced pores, presumably by inducing lipid bilayer fusion and sealing membrane gaps. Thus, lack of DynA increases the sensitivity to antibiotic exposure and phage infection. Taken together, our work suggests that DynA, and potentially other bacterial DLPs, contribute to the innate immunity of bacteria against membrane stress.

  16. Microbial activity and bacterial community structure during degradation of microcystins

    DEFF Research Database (Denmark)

    Christoffersen, K.; Lyck, Susanne; Winding, A.

    2002-01-01

    Degradation of realistic microcystin concentrations in lake water with indigenous bacteria was studied in laboratory and field experiments following inoculation with lysed toxic algal material containing microcystin primarily from Microcystis sp. or purified commercial microcystin-LR to microcosms...... experiment to evaluate the effects of organic lysates on bacterial proliferation in the absence of microcystin. An exponential decline of the dissolved toxins was observed in all cases with toxins present, and the degradation rates ranged between 0.5 and 1.0 d(-1). No lag phases were observed but slow...... including microcystins, and this resulted in a net accumulation of bacterial cells. The heterotrophic nanoflagellates responded quickly to the bacterial growth and probably consumed a considerable amount of the bacteria. The microbial activities returned to initial values within 5 to 6 d as the toxins...

  17. Anti-bacterial activity of some Brazilian medicinal plants.

    Science.gov (United States)

    de Lima, Maria Raquel Ferreira; de Souza Luna, Josiane; dos Santos, Aldenir Feitosa; de Andrade, Maria Cristina Caño; Sant'Ana, Antônio Euzébio Goulart; Genet, Jean-Pierre; Marquez, Béatrice; Neuville, Luc; Moreau, Nicole

    2006-04-21

    Extracts from various organs of 25 plants of Brazilian traditional medicine were assayed with respect to their anti-bacterial activities against Escherichia coli, a susceptible strain of Staphylococcus aureus and two resistant strains of Staphylococcus aureus harbouring the efflux pumps NorA and MsrA. Amongst the 49 extracts studied, 14 presented anti-bacterial activity against Staphylococcus aureus, including the ethanolic extracts from the rhizome of Jatropha elliptica, from the stem barks of Schinus terebinthifolius and Erythrina mulungu, from the stems and leaves of Caesalpinia pyramidalis and Serjania lethalis, and from the stem bark and leaves of Lafoensia pacari. The classes of compounds present in the active extracts were determined as a preliminary step towards their bioactivity-guided separation. No extracts were active against Escherichia coli.

  18. Metatranscriptomics reveals overall active bacterial composition in caries lesions

    Directory of Open Access Journals (Sweden)

    Aurea Simón-Soro

    2014-10-01

    Full Text Available Background: Identifying the microbial species in caries lesions is instrumental to determine the etiology of dental caries. However, a significant proportion of bacteria in carious lesions have not been cultured, and the use of molecular methods has been limited to DNA-based approaches, which detect both active and inactive or dead microorganisms. Objective: To identify the RNA-based, metabolically active bacterial composition of caries lesions at different stages of disease progression in order to provide a list of potential etiological agents of tooth decay. Design: Non-cavitated enamel caries lesions (n=15 and dentin caries lesions samples (n=12 were collected from 13 individuals. RNA was extracted and cDNA was constructed, which was used to amplify the 16S rRNA gene. The resulting 780 bp polymerase chain reaction products were pyrosequenced using Titanium-plus chemistry, and the sequences obtained were used to determine the bacterial composition. Results: A mean of 4,900 sequences of the 16S rRNA gene with an average read length of 661 bp was obtained per sample, giving a comprehensive view of the active bacterial communities in caries lesions. Estimates of bacterial diversity indicate that the microbiota of cavities is highly complex, each sample containing between 70 and 400 metabolically active species. The composition of these bacterial consortia varied among individuals and between caries lesions of the same individuals. In addition, enamel and dentin lesions had a different bacterial makeup. Lactobacilli were found almost exclusively in dentin cavities. Streptococci accounted for 40% of the total active community in enamel caries, and 20% in dentin caries. However, Streptococcus mutans represented only 0.02–0.73% of the total bacterial community. Conclusions: The data indicate that the etiology of dental caries is tissue dependent and that the disease has a clear polymicrobial origin. The low proportion of mutans streptococci

  19. Active bacterial community structure along vertical redox gradients in Baltic Sea sediment

    Energy Technology Data Exchange (ETDEWEB)

    Jansson, Janet; Edlund, Anna; Hardeman, Fredrik; Jansson, Janet K.; Sjoling, Sara

    2008-05-15

    Community structures of active bacterial populations were investigated along a vertical redox profile in coastal Baltic Sea sediments by terminal-restriction fragment length polymorphism (T-RFLP) and clone library analysis. According to correspondence analysis of T-RFLP results and sequencing of cloned 16S rRNA genes, the microbial community structures at three redox depths (179 mV, -64 mV and -337 mV) differed significantly. The bacterial communities in the community DNA differed from those in bromodeoxyuridine (BrdU)-labeled DNA, indicating that the growing members of the community that incorporated BrdU were not necessarily the most dominant members. The structures of the actively growing bacterial communities were most strongly correlated to organic carbon followed by total nitrogen and redox potentials. Bacterial identification by sequencing of 16S rRNA genes from clones of BrdU-labeled DNA and DNA from reverse transcription PCR (rt-PCR) showed that bacterial taxa involved in nitrogen and sulfur cycling were metabolically active along the redox profiles. Several sequences had low similarities to previously detected sequences indicating that novel lineages of bacteria are present in Baltic Sea sediments. Also, a high number of different 16S rRNA gene sequences representing different phyla were detected at all sampling depths.

  20. RNA structures are involved in the thermoregulation of bacterial virulence-associated traits.

    Science.gov (United States)

    Grosso-Becera, María Victoria; Servín-González, Luis; Soberón-Chávez, Gloria

    2015-08-01

    Pathogenic bacteria are exposed to temperature changes during colonization of the human body and during exposure to environmental conditions. Virulence-associated traits are mainly expressed by pathogenic bacteria at 37°C. We review different cases of post-transcriptional regulation of virulence-associated proteins through RNA structures (called RNA thermometers or RNATs) that modulate the translation of mRNAs. The analysis of RNATs in pathogenic bacteria has started to produce a comprehensive picture of the structures involved, and of the genes regulated by this mechanism. However, we are still not able to predict the functionality of putative RNATs predicted by bioinformatics methods, and there is not a global approach to measure the effect of these RNA structures in gene regulation during bacterial infections. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Metabolic pathways of Pseudomonas aeruginosa involved in competition with respiratory bacterial pathogens

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    Marie eBeaume

    2015-04-01

    Full Text Available Background: Chronic airway infection by Pseudomonas aeruginosa considerably contributes to lung tissue destruction and impairment of pulmonary function in cystic-fibrosis (CF patients. Complex interplays between P. aeruginosa and other co-colonizing pathogens including Staphylococcus aureus, Burkholderia spp and Klebsiella pneumoniae may be crucial for pathogenesis and disease progression.Methods: We generated a library of PA14 transposon insertion mutants to identify P. aeruginosa genes required for exploitative and direct competitions with S. aureus, B. cenocepacia, and K. pneumoniae. Results: Whereas wild type PA14 inhibited S. aureus growth, two transposon insertions located in pqsC and carB, resulted in reduced growth inhibition. PqsC is involved in the synthesis of 4-hydroxy-2-alkylquinolines (HAQs, a family of molecules having antibacterial properties, while carB is a key gene in pyrimidine biosynthesis. The carB mutant was also unable to grow in the presence of B. cepacia and K. pneumoniae but not E. coli and S. epidermidis. We further identified a transposon insertion in purF, encoding a key enzyme of purine metabolism. This mutant displayed a severe growth deficiency in the presence of Gram-negative but not of Gram-positive bacteria. We identified a beneficial interaction in a bioA transposon mutant, unable to grow on rich medium. This growth defect could be restored either by addition of biotin or by co-culturing the mutant in the presence of K. pneumoniae or E. coli.Conclusions: Complex interactions take place between the various bacterial species colonizing CF-lungs. This work identified both detrimental and beneficial interactions occurring between P. aeruginosa and three other respiratory pathogens involving several major metabolic pathways. Manipulating these pathways could be used to interfere with bacterial interactions and influence the colonization by respiratory pathogens.

  2. Chitinolytic bactery activity isolated from the mud fields

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    Nuniek Herdyastuti

    2012-01-01

    Full Text Available A chitinolytic microorganism had been isolated from mud fields in Ketintang Surabaya area by using a minimal media containing 0.4% colloidal chitin. Activity assay is based on released N-acetyl-glucosamine which reacted with 3,5 dinitrosalicyclic acid. Mud fields produce 63 bacterial isolates with chitinase activity (TNH1 – TNH63 isolates. The highest activity was shown by TNH11 isolate with specific activity 1.27 U/mg. TNH11 isolates was Gram negative, rod-cocoid cell, has a colony of yellow, round shape, convex elevation, flat margin and the colony diameter 3–5 mm.

  3. Structure and activity of lacustrine sediment bacteria involved in nutrient and iron cycles

    DEFF Research Database (Denmark)

    da Silva Martins, Gilberto Jorge; Terada, Akihiko; Ribeiro, Daniel C;

    2011-01-01

    Knowledge of the bacterial community structure in sediments is essential to better design restoration strategies for eutrophied lakes. In this regard, the aim of this study was to quantify the abundance and activity of bacteria involved in nutrient and iron cycling in sediments from four Azorean ...

  4. Mercury methylation and bacterial activity associated to tropical phytoplankton

    Energy Technology Data Exchange (ETDEWEB)

    Coelho-Souza, Sergio A. [Laboratorio de Tracadores Wolfgang Pfeiffer, SL 62, Instituto de Biofisica Carlos Chagas Filho, Bloco G, Ilha do Fundao, Universidade Federal do Rio de Janeiro (IBCCF/UFRJ), RJ, CEP 21949-900 (Brazil); Guimaraes, Jean R.D. [Laboratorio de Tracadores Wolfgang Pfeiffer, SL 62, Instituto de Biofisica Carlos Chagas Filho, Bloco G, Ilha do Fundao, Universidade Federal do Rio de Janeiro (IBCCF/UFRJ), RJ, CEP 21949-900 (Brazil)]. E-mail: jeanrdg@biof.ufrj.br; Mauro, Jane B.N. [Laboratorio de Tracadores Wolfgang Pfeiffer, SL 62, Instituto de Biofisica Carlos Chagas Filho, Bloco G, Ilha do Fundao, Universidade Federal do Rio de Janeiro (IBCCF/UFRJ), RJ, CEP 21949-900 (Brazil); Miranda, Marcio R. [Laboratorio de Tracadores Wolfgang Pfeiffer, SL 62, Instituto de Biofisica Carlos Chagas Filho, Bloco G, Ilha do Fundao, Universidade Federal do Rio de Janeiro (IBCCF/UFRJ), RJ, CEP 21949-900 (Brazil); Azevedo, Sandra M.F.O. [Laboratorio de Ecofisiologia e Toxicologia de Cianobacterias, IBCCF/UFRJ, RJ (Brazil)

    2006-07-01

    The methylated form of mercury (Hg), methylmercury (MeHg), is one of the most toxic pollutants. Biotic and/or abiotic methylation, often associated to sulfate-reducing bacteria metabolism, occurs in aquatic environments and in many tropical areas, mostly in the periphyton associated to floating macrophyte roots. Data about mercury methylation by phytoplankton are scarce and the aim of this study was to verify the biotic influence in the methylation process in Microcystis aeruginosa and Sineccocystis sp. laboratory strains and in natural populations of phytoplankton from two different aquatic systems, the mesotrophic Ribeirao das Lajes reservoir and hypereutrophic oligohaline Jacarepagua lagoon, Rio de Janeiro state, Brazil. Adapted radiochemical techniques were used to measure sulfate-reduction, mercury methylation and bacterial activity in phytoplankton samples. Methyl-{sup 203}Hg formation from added inorganic {sup 203}Hg and {sup 3}H-Leucine uptake were measured by liquid scintillation as well as sulfate-reduction, estimated as H{sub 2} {sup 35}S produced from added Na{sub 2} {sup 35}SO{sub 4}. There was no significant difference in low methylation potentials (0.37%) among the two cyanobacterium species studied in laboratory conditions. At Ribeirao das Lajes reservoir, there was no significant difference in methylation, bacterial activity and sulfate-reduction of surface sediment between the sampling points. Methylation in sediments (3-4%) was higher than in phytoplankton (1.5%), the opposite being true for bacterial activity (sediment mean 6.6 against 150.3 nmol gdw{sup -1} h{sup -1} for phytoplankton samples). At Jacarepagua lagoon, an expressive bacterial activity (477.1 x 10{sup 3} nmol gdw{sup -1} h{sup -1} at a concentration of 1000 nM leucine) and sulfate-reduction ({approx}21% H{sub 2} {sup 35}S trapped) associated to phytoplankton (mostly cyanobacteria M. aeruginosa) was observed, but mercury methylation was not detected.

  5. Activation of AMPK enhances neutrophil chemotaxis and bacterial killing.

    Science.gov (United States)

    Park, Dae Won; Jiang, Shaoning; Tadie, Jean-Marc; Stigler, William S; Gao, Yong; Deshane, Jessy; Abraham, Edward; Zmijewski, Jaroslaw W

    2013-11-08

    An inability of neutrophils to eliminate invading microorganisms is frequently associated with severe infection and may contribute to the high mortality rates associated with sepsis. In the present studies, we examined whether metformin and other 5' adenosine monophosphate-activated protein kinase (AMPK) activators affect neutrophil motility, phagocytosis and bacterial killing. We found that activation of AMPK enhanced neutrophil chemotaxis in vitro and in vivo, and also counteracted the inhibition of chemotaxis induced by exposure of neutrophils to lipopolysaccharide (LPS). In contrast, small interfering RNA (siRNA)-mediated knockdown of AMPKα1 or blockade of AMPK activation through treatment of neutrophils with the AMPK inhibitor compound C diminished neutrophil chemotaxis. In addition to their effects on chemotaxis, treatment of neutrophils with metformin or aminoimidazole carboxamide ribonucleotide (AICAR) improved phagocytosis and bacterial killing, including more efficient eradication of bacteria in a mouse model of peritonitis-induced sepsis. Immunocytochemistry showed that, in contrast to LPS, metformin or AICAR induced robust actin polymerization and distinct formation of neutrophil leading edges. Although LPS diminished AMPK phosphorylation, metformin or AICAR was able to partially decrease the effects of LPS/toll-like receptor 4 (TLR4) engagement on downstream signaling events, particularly LPS-induced IκBα degradation. The IκB kinase (IKK) inhibitor PS-1145 diminished IκBα degradation and also prevented LPS-induced inhibition of chemotaxis. These results suggest that AMPK activation with clinically approved agents, such as metformin, may facilitate bacterial eradication in sepsis and other inflammatory conditions associated with inhibition of neutrophil activation and chemotaxis.

  6. Effect of temperature, pH and detergents on the antifungal activity of bacterial culture filtrates against Mycosphaerella fijiensis

    Directory of Open Access Journals (Sweden)

    Eilyn Mena

    2014-01-01

    Full Text Available The bacteria associated to crops have been studied as potential biocontrol agents. However, few investigations on the interaction Musa spp. - Mycosphaerella fijiensis-Musa associated bacteria have been developed. Consequently, bacterial metabolites involved and the effect on them of physical and chemical factors remain unknown. Therefore, this study aimed to determine the effect of temperature, pH and detergents on bacterial culture filtrates with antifungal activity in vitro against Mycosphaerella fijiensis. The pathogen growth inhibition was assessed by absorbance reading at OD 565nm. It was found that the antifungal activity of the bacterial culture filtrates against M. fijiensis, varied in the presence of different values of temperature, pH, and types of detergents and this was related to the bacterial strain. The results suggested the possible protein nature of the metabolites with antifungal activity. Keywords: bacteria, biological control, antifungal metabolites

  7. Cj1411c GENE OF CAMPYLOBACTER JEJUNI 11168 ENCODES FOR A CYTOCHROME P450 INVOLVED IN BACTERIAL CAPSULE SUGAR METABOLISM

    Directory of Open Access Journals (Sweden)

    N. CORCIONIVOSCHI

    2013-12-01

    Full Text Available After isolation in 1970s, Campylobacter jejuni become the most commonlyrecognized cause of bacterial gastroenteritis in man. In animals is frequently foundin bovines on ovines. Publishing of the genome sequence of Campylobacter jejuni11168 (Parkhill, 2000 revealed the presence of only one cytochrome P450 in anoperon involved in sugar and cell surface biosynthesis. The gene name is Cj1411c, is1359 bp long and encodes 453 aa. The sequence is strictly conserved inCampylobacter jejuni RM221. Similarities with two cytochrome P450s, one formSilicobacter sp. and one form Poloromonas sp., were identified. These two enzymesare known to be involved in ascorbate and aldarate metabolism. The recombinantconstruct allowed the expression of active P450 enzyme with a 450 nm peak whenbinds CO. The protein was purified in proportion of ~ 70 %. By deleting the P450gene from the Campylobacter jejuni 11168 genome clear changes in cellmorphology were identified cells becoming wider and shorter. The capsular sugarprofile of the NCI strain reveals the presence of arabinose which was not found inthe wild type strain. The arabinose was identified by both High Performance LiquidChromatography (HPLC and Nuclear Magnetic Resonance (NMR.

  8. [Involvement of soluble mediators of inflammation in the pathogenic agent interaction--immune system in acute bacterial meningitis].

    Science.gov (United States)

    Lerescu, L; Tucureanu, C; Caraş, Iuliana; Pitica, Ramona; Ungureanu, Vasilica; Sălăgeanu, Aurora

    2008-01-01

    Acute Bacterial Meningitis is a medical emergency, which warrants early diagnosis and aggressive therapy, which in most cases must be initiated as an "empirical" treatment. Such an approach needs permanent epidemiological surveillance due to the major variability of the etiological agents depending upon time, geographical areas and demographic characteristics of the population. A program for the surveillance of meningitis is in progress in Romania, but the available clinical inbformation is incomplete and not well documented by paraclinical data, poorly reflecting the real incidence of the disease. The specific anatomic localization of the disease has major influences on the antiinfectious immune response. Inflammation is involved in the disease pathogenesis, especially in promotion and evolution of neurological sequelae (neuronal demyelinisation and degeneration) even in case of pathogen clearance following antimicrobial therapy. Activation of the immune response in a immunologically "privileged "region can lead to the break of tolerance and induction of autoimmunity (neuronal degenerescence). On the other hand, an efficient immune response is necessary for the clearance of pathogenic agents. A detailed investigation of the interaction between pathogenic agents and the immune system in relation to the particular meningeal localization and also a study on the involvement of soluble mediators of inflammation (cytokines, chemokines) in the pathogenesis of meningitis might prove useful for differential diagnosis (viral or "aseptic" meningitis) and also for elucidating the mechanisms which that underlie the disease pathogenesis/neurological complications.

  9. Cj1411c GENE OF CAMPYLOBACTER JEJUNI 11168 ENCODES FOR A CYTOCHROME P450 INVOLVED IN BACTERIAL CAPSULE SUGAR METABOLISM

    Directory of Open Access Journals (Sweden)

    CORCIONIVOSCHI N.

    2007-01-01

    Full Text Available After isolation in 1970s, Campylobacter jejuni become the most commonlyrecognized cause of bacterial gastroenteritis in man. In animals is frequently foundin bovines on ovines. Publishing of the genome sequence of Campylobacter jejuni11168 (Parkhill, 2000 revealed the presence of only one cytochrome P450 in anoperon involved in sugar and cell surface biosynthesis. The gene name is Cj1411c, is1359 bp long and encodes 453 aa. The sequence is strictly conserved inCampylobacter jejuni RM221. Similarities with two cytochrome P450s, one formSilicobacter sp. and one form Poloromonas sp., were identified. These two enzymesare known to be involved in ascorbate and aldarate metabolism. The recombinantconstruct allowed the expression of active P450 enzyme with a 450 nm peak whenbinds CO. The protein was purified in proportion of ~ 70 %. By deleting the P450gene from the Campylobacter jejuni 11168 genome clear changes in cellmorphology were identified cells becoming wider and shorter. The capsular sugarprofile of the NCI strain reveals the presence of arabinose which was not found inthe wild type strain. The arabinose was identified by both High Performance LiquidChromatography (HPLC and Nuclear Magnetic Resonance (NMR.

  10. In Vivo Evaluation of Bacterial Infection Involving Morphologically Different Surgical Meshes

    NARCIS (Netherlands)

    Engelsman, Anton F.; van Dam, Gooitzen M.; van der Mei, Henny C.; Busscher, Henk J.; Ploeg, Rutger J.

    2010-01-01

    Objective: To study the influence of morphology of surgical meshes on the course of bacterial infection under the influence of the host immune system in an in vivo chronic bacterial infection model. Background: The use of prosthetic meshes has increased dramatically the last decades in abdominal wal

  11. Bacterial communities potentially involved in iron-cycling in Baltic Sea and North Sea sediments revealed by pyrosequencing

    DEFF Research Database (Denmark)

    Reyes, Carlen; Dellwig, Olaf; Dähnke, K.

    2016-01-01

    To gain insight into the bacterial communities involved in iron-(Fe) cycling under marine conditions, we analysed sediments with Fe-contents (0.5-1.5 wt %) from the suboxic zone at a marine site in the Skagerrak (SK) and a brackish site in the Bothnian Bay (BB) using 16S rRNA gene pyrosequencing....

  12. Bacterial community composition and extracellular enzyme activity in temperate streambed sediment during drying and rewetting.

    Directory of Open Access Journals (Sweden)

    Elisabeth Pohlon

    Full Text Available Droughts are among the most important disturbance events for stream ecosystems; they not only affect stream hydrology but also the stream biota. Although desiccation of streams is common in Mediterranean regions, phases of dryness in headwaters have been observed more often and for longer periods in extended temperate regions, including Central Europe, reflecting global climate change and enhanced water withdrawal. The effects of desiccation and rewetting on the bacterial community composition and extracellular enzyme activity, a key process in the carbon flow of streams and rivers, were investigated in a typical Central European stream, the Breitenbach (Hesse, Germany. Wet streambed sediment is an important habitat in streams. It was sampled and exposed in the laboratory to different drying scenarios (fast, intermediate, slow for 13 weeks, followed by rewetting of the sediment from the fast drying scenario via a sediment core perfusion technique for 2 weeks. Bacterial community structure was analyzed using CARD-FISH and TGGE, and extracellular enzyme activity was assessed using fluorogenic model substrates. During desiccation the bacterial community composition shifted toward composition in soil, exhibiting increasing proportions of Actinobacteria and Alphaproteobacteria and decreasing proportions of Bacteroidetes and Betaproteobacteria. Simultaneously the activities of extracellular enzymes decreased, most pronounced with aminopeptidases and less pronounced with enzymes involved in the degradation of polymeric carbohydrates. After rewetting, the general ecosystem functioning, with respect to extracellular enzyme activity, recovered after 10 to 14 days. However, the bacterial community composition had not yet achieved its original composition as in unaffected sediments within this time. Thus, whether the bacterial community eventually recovers completely after these events remains unknown. Perhaps this community undergoes permanent changes

  13. COMPOSITION AND ACTIVITY OF BACTERIAL COMMUNITY OF COAL TAILING

    Directory of Open Access Journals (Sweden)

    Blayda I. A.

    2014-10-01

    Full Text Available The aim of this research was to study the composition of aboriginal bacterial community of coal tailing and to evaluate lixiviation activity of different groups of microorganisms belonging to this community. Using standard microbiological techniques we obtained and quantified the saving cultures of microorganisms from different physiological groups — filamentous fungi, heterotrophic microorganisms, mesophilic and thermophilic moderately acidophilic sulfur-oxidizing chemolithotrophic bacteria. Their oxidative activity was also established. The optimal results were achieved for collective leaching of rare and heavy metals into the solution under thermophilic conditions, which are favorable for the growth and activity of Sulfobacillus and under mesophilic conditions with the usage of ferrous iron as an energy substrate. This confirms the leading role of A. ferrooxidans in the processes of bacterial leaching of metals. Comparing our results with the available literature data we made a conclusion that the qualitative composition of acidophilic chemolithotrophic bacteria living in technogenic waste did not differ from the microbiocenose structure of natural sulfide ores.

  14. Measuring psychological engagement in youth activity involvement.

    Science.gov (United States)

    Ramey, Heather L; Rose-Krasnor, Linda; Busseri, Michael A; Gadbois, Shannon; Bowker, Anne; Findlay, Leanne

    2015-12-01

    Although psychological engagement (e.g., enjoyment, concentration) may be critical in fostering positive outcomes of youth activity participation, too few studies have been conducted to establish its role in development. Furthermore, an established measurement tool is lacking. In the current study, we evaluated a brief engagement measure with two Canadian samples of youth (Sample 1, N = 290, mean age = 16.9 years, 62% female; Sample 2, N = 1827, mean age = 13.1 years, 54% female). We conducted a confirmatory factor analysis with structural equation modeling to examine the hypothesized structure of the model. We also assessed the measure's validity by testing relations between engagement and both perceived outcomes and positive features of activity settings. Psychological engagement was best captured by three latent cognitive, affective, and relational/spiritual factors and a second-order latent factor. Also, as anticipated, psychological engagement was associated with features of the activity setting and perceived impact.

  15. A bacterial tyrosine phosphatase inhibits plant pattern recognition receptor activation.

    Science.gov (United States)

    Macho, Alberto P; Schwessinger, Benjamin; Ntoukakis, Vardis; Brutus, Alexandre; Segonzac, Cécile; Roy, Sonali; Kadota, Yasuhiro; Oh, Man-Ho; Sklenar, Jan; Derbyshire, Paul; Lozano-Durán, Rosa; Malinovsky, Frederikke Gro; Monaghan, Jacqueline; Menke, Frank L; Huber, Steven C; He, Sheng Yang; Zipfel, Cyril

    2014-03-28

    Innate immunity relies on the perception of pathogen-associated molecular patterns (PAMPs) by pattern-recognition receptors (PRRs) located on the host cell's surface. Many plant PRRs are kinases. Here, we report that the Arabidopsis receptor kinase EF-TU RECEPTOR (EFR), which perceives the elf18 peptide derived from bacterial elongation factor Tu, is activated upon ligand binding by phosphorylation on its tyrosine residues. Phosphorylation of a single tyrosine residue, Y836, is required for activation of EFR and downstream immunity to the phytopathogenic bacterium Pseudomonas syringae. A tyrosine phosphatase, HopAO1, secreted by P. syringae, reduces EFR phosphorylation and prevents subsequent immune responses. Thus, host and pathogen compete to take control of PRR tyrosine phosphorylation used to initiate antibacterial immunity.

  16. Ceftaroline activity tested against contemporary Latin American bacterial pathogens (2011

    Directory of Open Access Journals (Sweden)

    Robert K. Flamm

    2014-04-01

    Full Text Available A total of 2484 target bacterial pathogens were collected (one per patient episode from patients in 16 Latin American medical centers located in seven nations during 2011. Isolate identity was confirmed at a coordinating laboratory and susceptibility testing was performed for ceftaroline and comparator agents according to reference broth microdilution methods. A total of 30.0% of isolates were from respiratory tract, 29.4% from skin and skin structure, 21.4% from blood stream, 7.9% from urinary tract and 11.3% from other sites. Ceftaroline was active againstStaphylococcus aureus (42.8% MRSA with 83.6% of the isolates at 90.0% of the non-ESBL-phenotype. The spectrum of activity of ceftaroline against pathogens from Latin America indicates that it merits further study for its potential use in the Latin American region.

  17. Impaired bacterial attachment to light activated Ni-Ti alloy

    Energy Technology Data Exchange (ETDEWEB)

    Chrzanowski, Wojciech; Valappil, Sabeel P. [UCL Eastman Dental Institute, Division of Biomaterials and Tissue Engineering, 256 Gray' s In Road, WC1X 8LD, London (United Kingdom); Dunnill, Charles W. [University College London, Centre for Materials Chemistry, Chemistry Department, 20 Gordon Street, London, WC1H 0AJ (United Kingdom); Abou Neel, Ensanya A. [UCL Eastman Dental Institute, Division of Biomaterials and Tissue Engineering, 256 Gray' s In Road, WC1X 8LD, London (United Kingdom); Lee, Kevin [London Centre for Nanotechnology, 17-19 Gordon Street, London WC1H 0AH (United Kingdom); Parkin, Ivan P. [University College London, Centre for Materials Chemistry, Chemistry Department, 20 Gordon Street, London, WC1H 0AJ (United Kingdom); Wilson, Michael [UCL Eastman Dental Institute, Division of Microbial Diseases, 256 Gray' s In Road, WC1X 8LD, London (United Kingdom); Armitage, David A. [De Montfort University, Leicester School of Pharmacy, The Gateway, Leicester, LE1 9BH (United Kingdom); Knowles, Jonathan C., E-mail: j.knowles@eastman.ucl.ac.uk [UCL Eastman Dental Institute, Division of Biomaterials and Tissue Engineering, 256 Gray' s In Road, WC1X 8LD, London (United Kingdom)

    2010-01-30

    Ni-Ti alloy due to its unique mechanical properties, is used for many types of implants. Failure of these implants can be attributed to many different factors; however infections are a common problem. In this paper, the attachment of the bacteria, Staphylococcus aureus, to the Ni-Ti surface modified by a range of processes with and without of light activation (used to elicit antimicrobial properties of materials) was assessed and related to different surface characteristics. Before the light activation the number of bacterial colony forming units was the greatest for the samples thermally oxidised at 600 deg. C. This sample and the spark oxidised samples showed the highest photocatalytic activity but only the thermally oxidised samples at 600 deg. C showed a significant drop of S. aureus attachment. The findings in this study indicate that light activation and treating samples at 600 deg. C is a promising method for Ni-Ti implant applications with inherent antimicrobial properties. Light activation was shown to be an effective way to trigger photocatalytic reactions on samples covered with relatively thick titanium dioxide via accumulation of photons in the surface and a possible increase in defects which may result in free oxygen. Moreover, light activation caused an increase in the total surface energy.

  18. Active depinning of bacterial droplets: the collective surfing of Bacillus subtilis

    Science.gov (United States)

    Hennes, Marc; Tailleur, Julien; Daerr, Adrian

    2016-11-01

    How systems are endowed with migration capacity is a fascinating question with implications ranging from the design of novel active systems to the control of microbial populations. Bacteria, which can be found in a variety of environments, have developed among the richest set of locomotion mechanisms both at the microscopic and collective levels. Here, we uncover experimentally a new mode of collective bacterial motility in humid environment through the depinning of bacterial droplets. While capillary forces are notoriously enormous at the bacterial scale, even capable of pinning water droplets of millimetric size on inclined surfaces, we show that bacteria are able to harness a variety of mechanisms to unpin contact lines, hence inducing a collective sliding of the colony. Contrary to flagella-dependent migration modes like swarming we show that this much faster colony surfing still occurs in mutant strains of Bacillus subtilis lacking flagella. The diversity of mechanisms involved in the active unpinning seen in our experiments suggests that collective surfing should be a generic mode of migration of microorganisms in humid environments. Bacttern Grant.

  19. mTORC1-Activated Monocytes Increase Tregs and Inhibit the Immune Response to Bacterial Infections

    Science.gov (United States)

    Tu, Huaijun; Guo, Wei; Wang, Shixuan; Xue, Ting; Yang, Fei; Zhang, Xiaoyan; Yang, Yazhi; Wan, Qian; Shi, Zhexin; Zhan, Xulong

    2016-01-01

    The TSC1/2 heterodimer, a key upstream regulator of the mTOR, can inhibit the activation of mTOR, which plays a critical role in immune responses after bacterial infections. Monocytes are an innate immune cell type that have been shown to be involved in bacteremia. However, how the mTOR pathway is involved in the regulation of monocytes is largely unknown. In our study, TSC1 KO mice and WT mice were infected with E. coli. When compared to WT mice, we found higher mortality, greater numbers of bacteria, decreased expression of coactivators in monocytes, increased numbers of Tregs, and decreased numbers of effector T cells in TSC1 KO mice. Monocytes obtained from TSC1 KO mice produced more ROS, IL-6, IL-10, and TGF-β and less IL-1, IFN-γ, and TNF-α. Taken together, our results suggest that the inhibited immune functioning in TSC1 KO mice is influenced by mTORC1 activation in monocytes. The reduced expression of coactivators resulted in inhibited effector T cell proliferation. mTORC1-activated monocytes are harmful during bacterial infections. Therefore, inhibiting mTORC1 signaling through rapamycin administration could rescue the harmful aspects of an overactive immune response, and this knowledge provides a new direction for clinical therapy.

  20. Anti-bacterial activity of the methanolic extract of leucas hyssopifolia (Benth.

    Directory of Open Access Journals (Sweden)

    Devendra Mishra

    2013-01-01

    Full Text Available Context: Methanolic extract of Leucas hyssopifolia roots was investigated for its anti-bacterial property. Aim: Evaluation of anti-bacterial activity of Leucas hyssopifolia Benth. Settings and Design: Roots of the plant were collected, extracted and finally evaluated for their anti-bacterial activity. Materials and Methods: Paper disc diffusion method and microdilution technique were employed for the determination of zone of inhibition and minimal inhibitory concentration, respectively. Results: The extract showed anti-bacterial activity against all the tested bacterial strains except Escherichia coli. Conclusions: Anti-bacterial activity of extract of Leucas hyssopifolia roots may be due to the presence of secondary plant metabolites like terpenoids, steroids and flavonoids, which are present in the extract. The extract can be further studied for the isolation of chemical compounds and their biological activity.

  1. The Biofilm Lifestyle Involves an Increase in Bacterial Membrane Saturated Fatty Acids.

    Science.gov (United States)

    Dubois-Brissonnet, Florence; Trotier, Elsa; Briandet, Romain

    2016-01-01

    Biofilm formation on contact surfaces contributes to persistence of foodborne pathogens all along the food and feed chain. The specific physiological features of bacterial cells embedded in biofilms contribute to their high tolerance to environmental stresses, including the action of antimicrobial compounds. As membrane lipid adaptation is a vital facet of bacterial response when cells are submitted to harsh or unstable conditions, we focused here on membrane fatty acid composition of biofilm cells as compared to their free-growing counterparts. Pathogenic bacteria (Staphylococcus aureus, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella Typhimurium) were cultivated in planktonic or biofilm states and membrane fatty acid analyses were performed on whole cells in both conditions. The percentage of saturated fatty acids increases in biofilm cells in all cases, with a concomitant decrease of branched-chain fatty acids for Gram-positive bacteria, or with a decrease in the sum of other fatty acids for Gram-negative bacteria. We propose that increased membrane saturation in biofilm cells is an adaptive stress response that allows bacteria to limit exchanges, save energy, and survive. Reprogramming of membrane fluidity in biofilm cells might explain specific biofilm behavior including bacterial recalcitrance to biocide action.

  2. Metabolic activity of bacterial cells enumerated by direct viable count

    Energy Technology Data Exchange (ETDEWEB)

    Roszak, D.B.; Colwell, R.R.

    1987-12-01

    The direct viable count (DVC) method was modified by incorporating radiolabeled substrates in microautoradiographic analyses to assess bacterial survival in controlled laboratory microcosms. The DVC method, which permits enumeration of culturable and nonculturable cells, discriminates those cells that are responsive to added nutrients but in which division is inhibited by the addition of nalidixic acid. The resulting elongated cells represent all viable cells; this includes those that are culturable on routine media and those that are not. Escherichia coli and Salmonella enteritidis were employed in the microcosm studies, and radiolabeled substrates included (methyl-tritium thymidine or (Uranium-Carbon 14) glutamic acid. Samples taken at selected intervals during the survival experiments were examined by epifluorescence microscopy to enumerate cells by the DVC and acridine orange direct count methods, as well as by culture methods. Good correlation was obtained for cell-associated metabolic activity, measured by microautoradiography and substrate responsiveness (by the DVC method) at various stages of survival. Of the cells responsive to nutrients by the DVC method, ca 90% were metabolically active by the microautoradiographic method. No significant difference was observed between DVC enumerations with or without added radiolabeled substrate.

  3. Effect of treatment of bacterial vaginosis on disease activity in rheumatoid arthritis

    OpenAIRE

    M Kalhor; M Abbasi; L. Amini; A. Barikani

    2016-01-01

    Background: Rheumatoid arthritis is one of the most common autoimmune diseases in women of reproductive age. Studies have shown that bacterial vaginosis can affect the activity of rheumatoid arthritis. Objective: The aim of this study was to investigate the effect of treatment of bacterial vaginosis on disease activity in rheumatoid arthritis. Methods: This interventional study was conducted in 100 women with rheumatoid arthritis (50 women with bacterial vaginosis and 50 women without b...

  4. Improvement of bacterial cellulose production by manipulating the metabolic pathways in which ethanol and sodium citrate involved.

    Science.gov (United States)

    Li, Yuanjing; Tian, Chunjie; Tian, Hua; Zhang, Jiliang; He, Xin; Ping, Wenxiang; Lei, Hong

    2012-12-01

    Nowadays, bacterial cellulose has played more and more important role as new biological material for food industry and medical and industrial products based on its unique properties. However, it is still a difficult task to improve the production of bacterial cellulose, especially a large number of byproducts are produced in the metabolic biosynthesis processes. To improve bacterial cellulose production, ethanol and sodium citrate are added into the medium during the fermentation, and the activities of key enzymes and concentration of extracellular metabolites are measured to assess the changes of the metabolic flux of the hexose monophosphate pathway (HMP), the Embden-Meyerhof-Parnas pathway (EMP), and the tricarboxylic acid cycle (TCA). Our results indicate that ethanol functions as energy source for ATP generation at the early stage of the fermentation in the HMP pathway and the supplementation of ethanol significantly reduces glycerol generation (a major byproduct). While in the EMP pathway, sodium citrate plays a key role, and its supplementation results in the byproducts (mainly acetic acid and pyruvic acid) entering the gluconeogenesis pathway for cellulose synthesis. Furthermore, by adding ethanol and sodium citrate, the main byproduct citric acid in the TCA cycle is also reduced significantly. It is concluded that bacterial cellulose production can be improved by increasing energy metabolism and reducing the formation of metabolic byproducts through the metabolic regulations of the bypasses.

  5. In vitro recombination catalyzed by bacterial class 1 integron integrase IntI1 involves cooperative binding and specific oligomeric intermediates.

    Directory of Open Access Journals (Sweden)

    Véronique Dubois

    Full Text Available Gene transfer via bacterial integrons is a major pathway for facilitating the spread of antibiotic resistance genes across bacteria. Recently the mechanism underlying the recombination catalyzed by class 1 integron recombinase (IntI1 between attC and attI1 was highlighted demonstrating the involvement of a single-stranded intermediary on the attC site. However, the process allowing the generation of this single-stranded substrate has not been determined, nor have the active IntI1*DNA complexes been identified. Using the in vitro strand transfer assay and a crosslink strategy we previously described we demonstrated that the single-stranded attC sequences could be generated in the absence of other bacterial proteins in addition to IntI. This suggests a possible role for this protein in stabilizing and/or generating this structure. The mechanism of folding of the active IntI*DNA complexes was further analyzed and we show here that it involves a cooperative binding of the protein to each recombination site and the emergence of different oligomeric species specific for each DNA substrate. These findings provide further insight into the recombination reaction catalyzed by IntI1.

  6. Calcium Regulates the Activity and Structural Stability of Tpr, a Bacterial Calpain-like Peptidase.

    Science.gov (United States)

    Staniec, Dominika; Ksiazek, Miroslaw; Thøgersen, Ida B; Enghild, Jan J; Sroka, Aneta; Bryzek, Danuta; Bogyo, Matthew; Abrahamson, Magnus; Potempa, Jan

    2015-11-01

    Porphyromonas gingivalis is a peptide-fermenting asaccharolytic periodontal pathogen. Its genome contains several genes encoding cysteine peptidases other than gingipains. One of these genes (PG1055) encodes a protein called Tpr (thiol protease) that has sequence similarity to cysteine peptidases of the papain and calpain families. In this study we biochemically characterize Tpr. We found that the 55-kDa Tpr inactive zymogen proteolytically processes itself into active forms of 48, 37, and 33 kDa via sequential truncations at the N terminus. These processed molecular forms of Tpr are associated with the bacterial outer membrane where they are likely responsible for the generation of metabolic peptides required for survival of the pathogen. Both autoprocessing and activity were dependent on calcium concentrations >1 mm, consistent with the protein's activity within the intestinal and inflammatory milieus. Calcium also stabilized the Tpr structure and rendered the protein fully resistant to proteolytic degradation by gingipains. Together, our findings suggest that Tpr is an example of a bacterial calpain, a calcium-responsive peptidase that may generate substrates required for the peptide-fermenting metabolism of P. gingivalis. Aside from nutrient generation, Tpr may also be involved in evasion of host immune response through degradation of the antimicrobial peptide LL-37 and complement proteins C3, C4, and C5. Taken together, these results indicate that Tpr likely represents an important pathogenesis factor for P. gingivalis.

  7. Carboxyl-modified single-walled carbon nanotubes negatively affect bacterial growth and denitrification activity

    Science.gov (United States)

    Zheng, Xiong; Su, Yinglong; Chen, Yinguang; Wan, Rui; Li, Mu; Wei, Yuanyuan; Huang, Haining

    2014-07-01

    Single-walled carbon nanotubes (SWNTs) have been used in a wide range of fields, and the surface modification via carboxyl functionalization can further improve their physicochemical properties. However, whether carboxyl-modified SWNT poses potential risks to microbial denitrification after its release into the environment remains unknown. Here we present the possible effects of carboxyl-modified SWNT on the growth and denitrification activity of Paracoccus denitrificans (a model denitrifying bacterium). It was found that carboxyl-modified SWNT were present both outside and inside the bacteria, and thus induced bacterial growth inhibition at the concentrations of 10 and 50 mg/L. After 24 h of exposure, the final nitrate concentration in the presence of 50 mg/L carboxyl-modified SWNT was 21-fold higher than that in its absence, indicating that nitrate reduction was substantially suppressed by carboxyl-modified SWNT. The transcriptional profiling revealed that carboxyl-modified SWNT led to the transcriptional activation of the genes encoding ribonucleotide reductase in response to DNA damage and also decreased the gene expressions involved in glucose metabolism and energy production, which was an important reason for bacterial growth inhibition. Moreover, carboxyl-modified SWNT caused the significant down-regulation and lower activity of nitrate reductase, which was consistent with the decreased efficiency of nitrate reduction.

  8. Investigation of polymerase chain reaction assays to improve detection of bacterial involvement in bovine respiratory disease.

    Science.gov (United States)

    Bell, Colin J; Blackburn, Paul; Elliott, Mark; Patterson, Tony I A P; Ellison, Sean; Lahuerta-Marin, Angela; Ball, Hywel J

    2014-09-01

    Bovine respiratory disease (BRD) causes severe economic losses to the cattle farming industry worldwide. The major bacterial organisms contributing to the BRD complex are Mannheimia haemolytica, Histophilus somni, Mycoplasma bovis, Pasteurella multocida, and Trueperella pyogenes. The postmortem detection of these organisms in pneumonic lung tissue is generally conducted using standard culture-based techniques where the presence of therapeutic antibiotics in the tissue can inhibit bacterial isolation. In the current study, conventional and real-time polymerase chain reaction (PCR) assays were used to assess the prevalence of these 5 organisms in grossly pneumonic lung samples from 150 animals submitted for postmortem examination, and the results were compared with those obtained using culture techniques. Mannheimia haemolytica was detected in 51 cases (34%) by PCR and in 33 cases (22%) by culture, H. somni was detected in 35 cases (23.3%) by PCR and in 6 cases (4%) by culture, Myc. bovis was detected in 53 cases (35.3%) by PCR and in 29 cases (19.3%) by culture, P. multocida was detected in 50 cases (33.3%) by PCR and in 31 cases (20.7%) by culture, and T. pyogenes was detected in 42 cases (28%) by PCR and in 31 cases (20.7%) by culture, with all differences being statistically significant. The PCR assays indicated positive results for 111 cases (74%) whereas 82 cases (54.6%) were culture positive. The PCR assays have demonstrated a significantly higher rate of detection of all 5 organisms in cases of pneumonia in cattle in Northern Ireland than was detected by current standard procedures.

  9. Early canine plaque biofilms: characterization of key bacterial interactions involved in initial colonization of enamel.

    Directory of Open Access Journals (Sweden)

    Lucy J Holcombe

    Full Text Available Periodontal disease (PD is a significant problem in dogs affecting between 44% and 63.6% of the population. The main etiological agent for PD is plaque, a microbial biofilm that colonizes teeth and causes inflammation of the gingiva. Understanding how this biofilm initiates on the tooth surface is of central importance in developing interventions against PD. Although the stages of plaque development on human teeth have been well characterized little is known about how canine plaque develops. Recent studies of the canine oral microbiome have revealed distinct differences between the canine and human oral environments and the bacterial communities they support, particularly with respect to healthy plaque. These differences mean knowledge about the nature of plaque formation in humans may not be directly translatable to dogs. The aim of this study was to identify the bacterial species important in the early stages of canine plaque formation in vivo and then use isolates of these species in a laboratory biofilm model to develop an understanding of the sequential processes which take place during the initial colonization of enamel. Supra-gingival plaque samples were collected from 12 dogs at 24 and 48 hour time points following a full mouth descale and polish. Pyrosequencing of the 16S rDNA identified 134 operational taxonomic units after statistical analysis. The species with the highest relative abundance were Bergeyella zoohelcum, Neisseria shayeganii and a Moraxella species. Streptococcal species, which tend to dominate early human plaque biofilms, had very low relative abundance. In vitro testing of biofilm formation identified five primary colonizer species, three of which belonged to the genus Neisseria. Using these pioneer bacteria as a starting point, viable two and three species communities were developed. Combining in vivo and in vitro data has led us to construct novel models of how the early canine plaque biofilm develops.

  10. pH-responsive release behavior and anti-bacterial activity of bacterial cellulose-silver nanocomposites.

    Science.gov (United States)

    Shao, Wei; Liu, Hui; Liu, Xiufeng; Sun, Haijun; Wang, Shuxia; Zhang, Rui

    2015-05-01

    Bacterial cellulose (BC) has been extensively explored as some of the most promising biomaterials for biomedical applications due to their unique properties, such as high crystallinity, high mechanical strength, ultrafine fiber network structure, good water holding capacity and biocompatibility. However, BC is lack of anti-bacterial activity which is the main issue to be solved. In the study, BC-Ag nanocomposites were prepared in situ by introducing silver nanoparticles (AgNPs) into BC acting as the templates. The BC and as-prepared BC-Ag nanocomposites were characterized by several techniques including scanning electron microscope, Fourier transform infrared spectra, ultraviolet-visible absorption spectra, X-ray diffraction and thermogravimetric analyses. These results indicate AgNPs successfully impregnated into BC. The releases of Ag(+) at different pH values were studied, which showed pH-responsive release behaviors of BC-Ag nanocomposites. The anti-bacterial performances of BC-Ag nanocomposites were evaluated with Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 6538, Bacillus subtilis ATCC 9372 and Candida albicans CMCC(F) 98001, which frequently causes medical associated infections. The experimental results showed BC-Ag nanocomposites have excellent anti-bacterial activities, thus confirming its utility as potential wound dressings.

  11. Effect of Natural Sunlight on Bacterial Activity and Differential Sensitivity of Natural Bacterioplankton Groups in Northwestern Mediterranean Coastal Waters

    Science.gov (United States)

    Alonso-Sáez, Laura; Gasol, Josep M.; Lefort, Thomas; Hofer, Julia; Sommaruga, Ruben

    2006-01-01

    We studied the effects of natural sunlight on heterotrophic marine bacterioplankton in short-term experiments. We used a single-cell level approach involving flow cytometry combined with physiological probes and microautoradiography to determine sunlight effects on the activity and integrity of the cells. After 4 h of sunlight exposure, most bacterial cells maintained membrane integrity and viability as assessed by the simultaneous staining with propidium iodide and SYBR green I. In contrast, a significant inhibition of heterotrophic bacterial activity was detected, measured by 5-cyano-2,3 ditolyl tetrazolium chloride reduction and leucine incorporation. We applied microautoradiography combined with catalyzed reporter deposition-fluorescence in situ hybridization to test the sensitivity of the different bacterial groups naturally occurring in the Northwestern Mediterranean to sunlight. Members of the Gammaproteobacteria and Bacteroidetes groups appeared to be highly resistant to solar radiation, with small changes in activity after exposure. On the contrary, Alphaproteobacteria bacteria were more sensitive to radiation as measured by the cell-specific incorporation of labeled amino acids, leucine, and ATP. Within Alphaproteobacteria, bacteria belonging to the Roseobacter group showed higher resistance than members of the SAR11 cluster. The activity of Roseobacter was stimulated by exposure to photosynthetic available radiation compared to the dark treatment. Our results suggest that UV radiation can significantly affect the in situ single-cell activity of bacterioplankton and that naturally dominating phylogenetic bacterial groups have different sensitivity to natural levels of incident solar radiation. PMID:16957198

  12. Metatranscriptomic Analysis of Groundwater Reveals an Active Anammox Bacterial Population

    Science.gov (United States)

    Jewell, T. N. M.; Karaoz, U.; Thomas, B. C.; Banfield, J. F.; Brodie, E.; Williams, K. H.; Beller, H. R.

    2014-12-01

    Groundwater is a major natural resource, yet little is known about the contribution of microbial anaerobic ammonium oxidation (anammox) activity to subsurface nitrogen cycling. During anammox, energy is generated as ammonium is oxidized under anaerobic conditions to dinitrogen gas, using nitrite as the final electron acceptor. This process is a global sink for fixed nitrogen. Only a narrow range of monophyletic bacteria within the Planctomycetes carries out anammox, and the full extent of their metabolism, and subsequent impact on nitrogen cycling and microbial community structure, is still unknown. Here, we employ a metatranscriptomic analysis on enriched mRNA to identify the abundance and activity of a population of anammox bacteria within an aquifer at Rifle, CO. Planktonic biomass was collected over a two-month period after injection of up to 1.5 mM nitrate. Illumina-generated sequences were mapped to a phylogenetically binned Rifle metagenome database. We identified transcripts for genes with high protein sequence identities (81-98%) to those of anammox strain KSU-1 and to two of the five anammox bacteria genera, Brocadia and Kuenenia, suggesting an active, if not diverse, anammox population. Many of the most abundant anammox transcripts mapped to a single scaffold, indicative of a single dominant anammox species. Transcripts of the genes necessary for the anammox pathway were present, including an ammonium transporter (amtB), nitrite/formate transporter, nitrite reductase (nirK), and hydrazine oxidoreductase (hzoB). The form of nitrite reductase encoded by anammox is species-dependent, and we only identified nirK, with no evidence of anammox nirS. In addition to the anammox pathway we saw evidence of the anammox bacterial dissimilatory nitrate reduction to ammonium pathway (narH, putative nrfA, and nrfB), which provides an alternate means of generating substrates for anammox from nitrate, rather than relying on an external pool. Transcripts for hydroxylamine

  13. Moxibustion Activates Macrophage Autophagy and Protects Experimental Mice against Bacterial Infection

    Directory of Open Access Journals (Sweden)

    Xiaojuan Li

    2014-01-01

    Full Text Available Moxibustion is one of main therapies in traditional Chinese medicine and uses heat stimulation on the body surface from the burning of moxa to release pain or treat diseases. Emerging studies have shown that moxibustion can generate therapeutic effects by activating a series of signaling pathways and neuroendocrine-immune activities. Here we show moxibustion promoted profound macrophage autophagy in experimental Kunming mice, with reduced Akt phosphorylation and activated eIF2α phosphorylation. Consequently, moxibustion promoted bacterial clearance by macrophages and protected mice from mortality due to bacterial infection. These results indicate that moxibustion generates a protective response by activating autophagy against bacterial infections.

  14. Using metagenomics and metatranscriptomics to study specific bacterial species involved in biological phosphorus removal from wastewater

    DEFF Research Database (Denmark)

    Albertsen, Mads; McIlroy, Simon Jon; Stokholm-Bjerregaard, Mikkel

    profiles by metatranscriptomics. To demonstrate this we revisited the bacteria involved in enhanced biological phosphorus removal (EBPR) from wastewater treatment plants. The EBPR process is used all over the world, has a large body of information regarding the underlying microbiology, and is often studied...

  15. Analysis for the presence of determinants involved in the transport of mercury across bacterial membrane from polluted water bodies of India

    Directory of Open Access Journals (Sweden)

    Arif Tasleem Jan

    2016-03-01

    Full Text Available Abstract Mercury, which is ubiquitous and recalcitrant to biodegradation processes, threatens human health by escaping to the environment via various natural and anthropogenic activities. Non-biodegradability of mercury pollutants has necessitated the development and implementation of economic alternatives with promising potential to remove metals from the environment. Enhancement of microbial based remediation strategies through genetic engineering approaches provides one such alternative with a promising future. In this study, bacterial isolates inhabiting polluted sites were screened for tolerance to varying concentrations of mercuric chloride. Following identification, several Pseudomonas and Klebsiella species were found to exhibit the highest tolerance to both organic and inorganic mercury. Screened bacterial isolates were examined for their genetic make-up in terms of the presence of genes (merP and merT involved in the transport of mercury across the membrane either alone or in combination to deal with the toxic mercury. Gene sequence analysis revealed that the merP gene showed 86–99% homology, while the merT gene showed >98% homology with previously reported sequences. By exploring the genes involved in imparting metal resistance to bacteria, this study will serve to highlight the credentials that are particularly advantageous for their practical application to remediation of mercury from the environment.

  16. Detection of bacterial species involved in perimplantitis concerned with cultural and RT-PCR

    Directory of Open Access Journals (Sweden)

    Marcello Gatti

    2010-06-01

    Full Text Available Dental implants offer new treatment options for edentulous either partially or completely, now represent a viable alternative to conventional fixed protheses. Dental implants are colonized by a flora dominated by Gram-positive facultative aerobic, while in patients with bone loss and formation of pockets peri-implant diseases was found a significant difference in the composition of microflora, bacteria, Gram-negative anaerobes in particular Fusobacterium spp., Treponema denticola (Spirochetes, Tannerella forsythensis, Aggregatibacter actinomycetemcomitans, Prevotella intermedia as interim black-pigmented bacteria, Porphyromonas gingivalis, often in high concentrations. Aims. The purpose of this study was to identify those at risk of perimplantitis using 2 techniques: RT-PCR examination of trade and culture. The results were compared taking into consideration the advantages and disadvantages of both methods. Materials and methods.We studied 24 patients (14 women and 10 men, aged, women between 43 and 76 years, with an average of 63.8 + / - 10.9 years, men between 45 and 88 years with a average of 64.3 years + / - 12.5 years. Was performed a double levy of sub-gingival plaque at multiple sites that had an implant CAL (clinical attachment level> 4mm in order to assess the microbiological identification with the two techniques: Examining culture and Real-Time PCR of Commerce ( Gum-Sunstar that identifies 4 bacterial species: A. actinomycetemcomitans (A.a., P.gingivalis (P.g., T.forsythensis (T.f., and T.denticola (T.d.. Results. All patients studied were positive to both tests with charger high: the consideration of tenure, with CFU / ml > 105, was positive in 66.6% of samples by:T.f., and P.g., in 12.5% for A.a., while T.d. not been sought by examining culture, the RT-PCR was positive, with high loads, in 95.8% of samples for T.f., in 79.1% for P.g., in 12.5% for A.a. and 20.8% for T.d.The test crop showed the presence of even P.intermedia in 91

  17. Involvement of a bacterial microcompartment in the metabolism of fucose and rhamnose by Clostridium phytofermentans.

    Directory of Open Access Journals (Sweden)

    Elsa Petit

    Full Text Available BACKGROUND: Clostridium phytofermentans, an anaerobic soil bacterium, can directly convert plant biomass into biofuels. The genome of C. phytofermentans contains three loci with genes encoding shell proteins of bacterial microcompartments (BMC, organelles composed entirely of proteins. METHODOLOGY AND PRINCIPAL FINDINGS: One of the BMC loci has homology to a BMC-encoding locus implicated in the conversion of fucose to propanol and propionate in a human gut commensal, Roseburia inulinivorans. We hypothesized that it had a similar role in C. phytofermentans. When C. phytofermentans was grown on fucose, the major products identified were ethanol, propanol and propionate. Transmission electron microscopy of fucose- and rhamnose-grown cultures revealed polyhedral structures, presumably BMCs. Microarray analysis indicated that during growth on fucose, operons coding for the BMC locus, fucose dissimilatory enzymes, and an ATP-binding cassette transporter became the dominant transcripts. These data are consistent with fucose fermentation producing a 1,2-propanediol intermediate that is further metabolized in the microcompartment encoded in the BMC locus. Growth on another deoxyhexose sugar, rhamnose, resulted in the expression of the same BMC locus and similar fermentation products. However, a different set of dissimilatory enzymes and transport system genes were induced. Quite surprisingly, growth on fucose or rhamnose also led to the expression of a diverse array of complex plant polysaccharide-degrading enzymes. CONCLUSIONS/SIGNIFICANCE: Based on physiological, genomic, and microarray analyses, we propose a model for the fermentation of fucose and rhamnose in C. phytofermentans that includes enzymes encoded in the same BMC locus. Comparative genomic analysis suggests that this BMC may be present in other clostridial species.

  18. Demodex-associated bacterial proteins induce neutrophil activation.

    LENUS (Irish Health Repository)

    2012-02-01

    Background: Patients with rosacea demonstrate a higher density of Demodex mites in their skin than controls. A bacterium isolated from a Demodex mite from a patient with papulopustular rosacea (PPR) was previously shown to provoke an immune response in patients with PPR or ocular rosacea thus suggesting a possible role for bacterial proteins in the etiology of this condition. Objectives: To examine the response of neutrophils to proteins derived from a bacterium isolated from a Demodex mite. Methods: Bacterial cells were lysed and proteins were partially purified by AKTA-FPLC. Isolated neutrophils were exposed to bacterial proteins and monitored for alterations in migration, degranulation and cytokine production. Results: Neutrophils exposed to proteins from Bacillus cells demonstrated increased levels of migration and elevated release of MMP-9, an enzyme known to degrade collagen and cathelicidin, an antimicrobial peptide. In addition neutrophils exposed to the bacterial proteins demonstrated elevated rates of Il-8 and TNF-alpha production. Conclusions: Proteins produced by a bacterium isolated from a Demodex mite have the ability to increase the migration, degranulation and cytokine production abilities of neutrophils. These results suggest that bacteria may play a role in the inflammatory erythema associated with rosacea.

  19. Cytotoxic responses to 405nm light exposure in mammalian and bacterial cells: Involvement of reactive oxygen species.

    Science.gov (United States)

    Ramakrishnan, Praveen; Maclean, Michelle; MacGregor, Scott J; Anderson, John G; Grant, M Helen

    2016-06-01

    Light at wavelength 405 nm is an effective bactericide. Previous studies showed that exposing mammalian cells to 405 nm light at 36 J/cm(2) (a bactericidal dose) had no significant effect on normal cell function, although at higher doses (54 J/cm(2)), mammalian cell death became evident. This research demonstrates that mammalian and bacterial cell toxicity induced by 405 nm light exposure is accompanied by reactive oxygen species production, as detected by generation of fluorescence from 6-carboxy-2',7'-dichlorodihydrofluorescein diacetate. As indicators of the resulting oxidative stress in mammalian cells, a decrease in intracellular reduced glutathione content and a corresponding increase in the efflux of oxidised glutathione were observed from 405 nm light treated cells. The mammalian cells were significantly protected from dying at 54 J/cm(2) in the presence of catalase, which detoxifies H2O2. Bacterial cells were significantly protected by sodium pyruvate (H2O2 scavenger) and by a combination of free radical scavengers (sodium pyruvate, dimethyl thiourea (OH scavenger) and catalase) at 162 and 324 J/cm(2). Results therefore suggested that the cytotoxic mechanism of 405 nm light in mammalian cells and bacteria could be oxidative stress involving predominantly H2O2 generation, with other ROS contributing to the damage.

  20. Effects of forest management practices in temperate beech forests on bacterial and fungal communities involved in leaf litter degradation.

    Science.gov (United States)

    Purahong, Witoon; Kapturska, Danuta; Pecyna, Marek J; Jariyavidyanont, Katalee; Kaunzner, Jennifer; Juncheed, Kantida; Uengwetwanit, Tanaporn; Rudloff, Renate; Schulz, Elke; Hofrichter, Martin; Schloter, Michael; Krüger, Dirk; Buscot, François

    2015-05-01

    Forest management practices (FMPs) significantly influence important ecological processes and services in Central European forests, such as leaf litter decomposition and nutrient cycling. Changes in leaf litter diversity, and thus, its quality as well as microbial community structure and function induced by different FMPs were hypothesized to be the main drivers causing shifts in decomposition rates and nutrient release in managed forests. In a litterbag experiment lasting 473 days, we aimed to investigate the effects of FMPs (even-aged timber management, selective logging and unmanaged) on bacterial and fungal communities involved in leaf litter degradation over time. Our results showed that microbial communities in leaf litter were strongly influenced by both FMPs and sampling date. The results from nonmetric multidimensional scaling (NMDS) ordination revealed distinct patterns of bacterial and fungal successions over time in leaf litter. We demonstrated that FMPs and sampling dates can influence a range of factors, including leaf litter quality, microbial macronutrients, and pH, which significantly correlate with microbial community successions.

  1. Nucleoside analogues are activated by bacterial deoxyribonucleoside kinases in a species-specific manner

    DEFF Research Database (Denmark)

    Sandrini, Michael; Clausen, Anders; On, Stephen L. W.

    2007-01-01

    bactericidal activity against several clinical bacterial isolates and type strains. We identified and subcloned the genes coding for putative deoxyribonucleoside kinases in Escherichia coli, Pasteurella multocida, Salmonella enterica, Yersinia enterocolitica, Bacillus cereus, Clostridium perfringens...

  2. Evaluation of anti-bacterial and wound healing activity of the fruits of ...

    African Journals Online (AJOL)

    Evaluation of anti-bacterial and wound healing activity of the fruits of ... the functional roles of the fruits of Amorpha fruticosa L. during wound healing progress. ... fibroblasts proliferation and migration, leading to promotion of wound healing.

  3. Comparison of bacterial communities of conventional and A-stage activated sludge systems

    NARCIS (Netherlands)

    Gonzalez-Martinez, A.; Rodriguez-Sanchez, A.; Lotti, T.; Garcia-Ruiz, M.J.; Gonzalez-Lopez, J.; Van Loosdrecht, M.C.M.

    2016-01-01

    The bacterial community structure of 10 different wastewater treatment systems and their influents has been investigated through pyrosequencing, yielding a total of 283486 reads. These bioreactors had different technological configurations: conventional activated sludge (CAS) systems and very highly

  4. Bacterial abundance, communities and heterotrophic activities in the coastal waters off Tamil Nadu

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaiah, N.; Raghukumar, C.; Sheelu, G.; Chandramohan, D.

    abundance of CAHB and TDC was observed in most locations. Microbial heterotrophic uptake and respiration rates of labelled glucose were high (except off Madras) suggesting a highly active microflora at most of these locations. Many bacterial genera were seen...

  5. Investigation of Anti-bacterial Activity against Food-borne Pathogens among Korean Domestic Algae

    Directory of Open Access Journals (Sweden)

    Ki-hyo Jang

    2015-03-01

    Full Text Available The aim of this study is to explore algal species with anti-bacterial activity against six food-borne pathogens. Among 51 marine algae, Laurencia okamurae Yamada and Dictyopteris undulata Holmes was elucidated to have a potent anti-bacterial activity against food-borne pathogens. Laurencia okamurae Yamada showed the clear zone around agar well on B. cereus, S. aureusand L. monocytogenes-spreading agar plate. Dictyopteris undulata Holmes had the anti-bacterial activity against S. chorelaesuis, B. cereus, S. aureus and L. monocytogenes on bacterial spreading agar plates. Antibacterial activity of L. okamurae Yamada and D. undulata Holmes had specifically susceptibility for B. cereus, S. aureus and L. monocytogenes and were superior to streptomycin, the authentic antibiotics. It is anticipated that new food preservatives can be explored and developed on the basis of this study.

  6. Operationalising active involvement in the EU water framework directive

    DEFF Research Database (Denmark)

    Wright, Stuart Anthony Lewis; Fritsch, Oliver

    2011-01-01

    of actively involving non-state actors, which can be summarised as increasing the effectiveness of policy and improving its implementation. Criticising the emerging economic decision-making approach, we argue that economic analyses could result in a missed opportunity to capitalise on the potential benefits...... to comply with the statutory requirements of the Directive, but should strive for active involvement due to the potential for increasing the effectiveness of the Water Framework Directive and improving its implementation......We identify two key stages in the river basin planning process under the Water Framework Directive: the selection of instruments for a programme of measures to achieve the environmental targets, and disproportionate cost analysis to determine whether selected measures involve high costs. Some EU...

  7. Effect of flow and active mixing on bacterial growth in a colon-like geometry

    Science.gov (United States)

    Cremer, Jonas; Segota, Igor; Arnoldini, Markus; Groisman, Alex; Hwa, Terence

    The large intestine harbors bacteria from hundreds of species, with bacterial densities reaching up to 1012 cells per gram. Many different factors influence bacterial growth dynamics and thus bacterial density and microbiota composition. One dominant force is flow which can in principle lead to a washout of bacteria from the proximal colon. Active mixing by Contractions of the colonic wall together with bacterial growth might counteract such flow-forces and allow high bacterial densities to occur. As a step towards understanding bacterial growth in the presence of mixing and flow, we constructed an in-vitro setup where controlled wall-deformations of a channel emulate Contractions. We investigate growth along the channel under a steady nutrient inflow. In the limits of no or very frequent Contractions, the device behaves like a plug-flow reactor and a chemostat respectively. Depending on mixing and flow, we observe varying spatial gradients in bacterial density along the channel. Active mixing by deformations of the channel wall is shown to be crucial in maintaining a steady-state bacterial population in the presence of flow. The growth-dynamics is quantitatively captured by a simple mathematical model, with the effect of mixing described by an effective diffusion term.

  8. Active-involvement principle in dental health education

    DEFF Research Database (Denmark)

    Schou, L

    1985-01-01

    A basic problem in dental health education (DHE) is that the effect usually disappears shortly after the termination of a program. The purpose of the present study was to obtain long-term effect of a DHE-program by emphasizing the active involvement of the participants. The sample comprised...

  9. Adolescent Involvement in Extracurricular Activities: Influences on Leadership Skills

    Science.gov (United States)

    Hancock, Donna; Dyk, Patricia Hyjer; Jones, Kenneth

    2012-01-01

    Study examined adolescents' participation in sports, school, and community extracurricular activities to assess the influence of different involvement roles and adult support on leadership skills. The study found that males and females who perceived their adult support more positively had more positive perceptions of their leadership skills.…

  10. Activity Involvement in Aging Women: Career Pattern and Retirement.

    Science.gov (United States)

    Holahan, Carole Kovalic

    Some research has found that women's retirement from the labor force produces significant changes in their lives and requires further investigation. The effects of career pattern and retirement on activity involvement and life satisfaction for women who had been in the work force was investigated. Subjects were members of the Terman Study of the…

  11. Different Bacterial Communities Involved in Peptide Decomposition between Normoxic and Hypoxic Coastal Waters

    Science.gov (United States)

    Liu, Shuting; Wawrik, Boris; Liu, Zhanfei

    2017-01-01

    Proteins and peptides are key components of the labile dissolved organic matter pool in marine environments. Knowing which types of bacteria metabolize peptides can inform the factors that govern peptide decomposition and further carbon and nitrogen remineralization in marine environments. A 13C-labeled tetrapeptide, alanine-valine-phenylalanine-alanine (AVFA), was added to both surface (normoxic) and bottom (hypoxic) seawater from a coastal station in the northern Gulf of Mexico for a 2-day incubation experiment, and bacteria that incorporated the peptide were identified using DNA stable isotope probing (SIP). The decomposition rate of AVFA in the bottom hypoxic seawater (0.018–0.035 μM h-1) was twice as fast as that in the surface normoxic seawater (0.011–0.017 μM h-1). SIP experiments indicated that incorporation of 13C was highest among the Flavobacteria, Sphingobacteria, Alphaproteobacteria, Acidimicrobiia, Verrucomicrobiae, Cyanobacteria, and Actinobacteria in surface waters. In contrast, highest 13C-enrichment was mainly observed in several Alphaproteobacteria (Thalassococcus, Rhodobacteraceae, Ruegeria) and Gammaproteobacteria genera (Colwellia, Balneatrix, Thalassomonas) in the bottom water. These data suggest that a more diverse group of both oligotrophic and copiotrophic bacteria may be involved in metabolizing labile organic matter such as peptides in normoxic coastal waters, and several copiotrophic genera belonging to Alphaproteobacteria and Gammaproteobacteria and known to be widely distributed may contribute to faster peptide decomposition in the hypoxic waters. PMID:28326069

  12. The involvement of bacterial quorum sensing in the spoilage of refrigerated Litopenaeus vannamei.

    Science.gov (United States)

    Zhu, Suqin; Wu, Haohao; Zeng, Mingyong; Liu, Zunying; Wang, Ying

    2015-01-02

    quorum sensing involves the spoilage of refrigerated Litopenaeus vannamei.

  13. ATP-dependent transcriptional activation by bacterial PspF AAA+protein.

    Science.gov (United States)

    Schumacher, Jörg; Zhang, Xiaodong; Jones, Susan; Bordes, Patricia; Buck, Martin

    2004-05-14

    Transcription activation by bacterial sigma(54)-dependent enhancer-binding proteins (EBPs) requires their tri-nucleotide hydrolysis to restructure the sigma(54) RNA polymerase (RNAP). EBPs share sequence similarity with guanine nucleotide binding-proteins and ATPases associated with various cellular activities (AAA) proteins, especially in the mononucleotide binding P-loop fold. Using the phage shock protein F (PspF) EBP, we identify P-loop residues responsible for nucleotide binding and hydrolysis, consistent with their roles in other P-loop NTPases. We show the refined low-resolution structure of an EBP, PspF, revealing a hexameric ring organisation characteristic of AAA proteins. Functioning of EBPs involves ATP binding, higher oligomer formation and ATP hydrolysis coupled to the restructuring of the RNAP. This is thought to be a highly coordinated multi-step process, but the nucleotide-driven mechanism of oligomerisation and ATP hydrolysis is little understood. Our kinetic and structural data strongly suggest that three PspF dimers assemble to form a hexamer upon nucleotide binding. During the ATP hydrolysis cycle, both ATP and ADP are bound to oligomeric PspF, in line with a sequential hydrolysis cycle. We identify a putative R-finger, and show its involvement in ATP hydrolysis. Substitution of this arginine residue results in nucleotide-independent formation of hexameric rings, structurally linking the putative R-finger and, by inference, a specific nucleotide interaction to the control of PspF oligomerisation.

  14. Determination of bacterial activity by use of an evanescent-wave fiber-optic sensor

    Science.gov (United States)

    John, M. Shelly; Kishen, Anil; Sing, Lim Chu; Asundi, Anand

    2002-12-01

    A novel technique based on fiber-optic evanescent-wave spectroscopy is proposed for the detection of bacterial activity in human saliva. The sensor determines the specific concentration of Streptococcus mutans in saliva, which is a major causative factor in dental caries. In this design, one prepares the fiber-optic bacterial sensor by replacing a portion of the cladding region of a multimode fiber with a dye-encapsulated xerogel, using the solgel technique. The exponential decay of the evanescent wave at the core-cladding interface of a multimode fiber is utilized for the determination of bacterial activity in saliva. The acidogenic profile of Streptococcus mutans is estimated by use of evanescent-wave absorption spectra at various levels of bacterial activity.

  15. Bacterial Traits Involved in Colonization of Arabidopsis thaliana Roots by Bacillus amyloliquefaciens FZB42.

    Science.gov (United States)

    Dietel, Kristin; Beator, Barbara; Budiharjo, Anto; Fan, Ben; Borriss, Rainer

    2013-03-01

    Colonization studies previously performed with a green-fluorescent-protein, GFP, labeled derivative of Bacillus amyloliquefaciens FZB42 revealed that the bacterium behaved different in colonizing surfaces of plant roots of different species (Fan et al., 2012). In order to extend these studies and to elucidate which genes are crucial for root colonization, we applied targeted mutant strains to Arabidopsis seedlings. The fates of root colonization in mutant strains impaired in synthesis of alternative sigma factors, non-ribosomal synthesis of lipopeptides and polyketides, biofilm formation, swarming motility, and plant growth promoting activity were analyzed by confocal laser scanning microscopy. Whilst the wild-type strain heavily colonized surfaces of root tips and lateral roots, the mutant strains were impaired in their ability to colonize root tips and most of them were unable to colonize lateral roots. Ability to colonize plant roots is not only dependent on the ability to form biofilms or swarming motility. Six mutants, deficient in abrB-, sigH-, sigD-, nrfA-, yusV and RBAM017410, but not affected in biofilm formation, displayed significantly reduced root colonization. The nrfA- and yusV-mutant strains colonized border cells and, partly, root surfaces but did not colonize root tips or lateral roots.

  16. Bacterial Secretant from Pseudomonas aeruginosa Dampens Inflammasome Activation in a Quorum Sensing-Dependent Manner

    Science.gov (United States)

    Yang, Jungmin; Lee, Kang-Mu; Park, Sangjun; Cho, Yoeseph; Lee, Eunju; Park, Jong-Hwan; Shin, Ok Sarah; Son, Junghyun; Yoon, Sang Sun; Yu, Je-Wook

    2017-01-01

    Inflammasome signaling can contribute to host innate immune defense against bacterial pathogens such as Pseudomonas aeruginosa. However, bacterial evasion of host inflammasome activation is still poorly elucidated. Quorum sensing (QS) is a bacterial communication mechanism that promotes coordinated adaptation by triggering expression of a wide range of genes. QS is thought to strongly contribute to the virulence of P. aeruginosa, but the molecular impact of bacterial QS on host inflammasome defense is completely unknown. Here, we present evidence that QS-related factors of the bacterial secretant (BS) from P. aeruginosa can dampen host inflammasome signaling in mouse bone marrow-derived macrophages. We found that BS from QS-defective ΔlasR/rhlR mutant, but not from wild-type (WT) P. aeruginosa, induces robust activation of the NLRC4 inflammasome. P. aeruginosa-released flagellin mediates this inflammasome activation by ΔlasR/rhlR secretant, but QS-regulated bacterial proteases in the WT BS impair extracellular flagellin to attenuate NLRC4 inflammasome activation. P. aeruginosa-secreted proteases also degrade inflammasome components in the extracellular space to inhibit the propagation of inflammasome-mediated responses. Furthermore, QS-regulated virulence factor pyocyanin and QS autoinducer 3-oxo-C12-homoserine lactone directly suppressed NLRC4- and even NLRP3-mediated inflammasome assembly and activation. Taken together, our data indicate that QS system of P. aeruginosa facilitates bacteria to evade host inflammasome-dependent sensing machinery. PMID:28396663

  17. Lysozyme-coated silver nanoparticles for differentiating bacterial strains on the basis of antibacterial activity

    Science.gov (United States)

    Ashraf, Sumaira; Chatha, Mariyam Asghar; Ejaz, Wardah; Janjua, Hussnain Ahmed; Hussain, Irshad

    2014-10-01

    Lysozyme, an antibacterial enzyme, was used as a stabilizing ligand for the synthesis of fairly uniform silver nanoparticles adopting various strategies. The synthesized particles were characterized using UV-visible spectroscopy, FTIR, dynamic light scattering (DLS), and TEM to observe their morphology and surface chemistry. The silver nanoparticles were evaluated for their antimicrobial activity against several bacterial species and various bacterial strains within the same species. The cationic silver nanoparticles were found to be more effective against Pseudomonas aeruginosa 3 compared to other bacterial species/strains investigated. Some of the bacterial strains of the same species showed variable antibacterial activity. The difference in antimicrobial activity of these particles has led to the conclusion that antimicrobial products formed from silver nanoparticles may not be equally effective against all the bacteria. This difference in the antibacterial activity of silver nanoparticles for different bacterial strains from the same species may be due to the genome islands that are acquired through horizontal gene transfer (HGT). These genome islands are expected to possess some genes that may encode enzymes to resist the antimicrobial activity of silver nanoparticles. These silver nanoparticles may thus also be used to differentiate some bacterial strains within the same species due to variable silver resistance of these variants, which may not possible by simple biochemical tests.

  18. Characterization of CCN and IN activity of bacterial isolates collected in Atlanta, GA

    Science.gov (United States)

    Purdue, Sara; Waters, Samantha; Karthikeyan, Smruthi; Konstantinidis, Kostas; Nenes, Athanasios

    2016-04-01

    Characterization of CCN activity of bacteria, other than a few select types such as Pseudomonas syringae, is limited, especially when looked at in conjunction with corresponding IN activity. The link between these two points is especially important for bacteria as those that have high CCN activity are likely to form an aqueous phase required for immersion freezing. Given the high ice nucleation temperature of bacterial cells, especially in immersion mode, it is important to characterize the CCN and IN activity of many different bacterial strains. To this effect, we developed a droplet freezing assay (DFA) which consists of an aluminum cold plate, cooled by a continuous flow of an ethylene glycol-water mixture, in order to observe immersion freezing of the collected bacteria. Here, we present the initial results on the CCN and IN activities of bacterial samples we have collected in Atlanta, GA. Bacterial strains were collected and isolated from rainwater samples taken from different storms throughout the year. We then characterized the CCN activity of each strain using a DMT Continuous Flow Streamwise Thermal Gradient CCN Counter by exposing the aerosolized bacteria to supersaturations ranging from 0.05% to 0.6%. Additionally, using our new DFA, we characterized the IN activity of each bacterial strain at temperatures ranging from -20oC to 0oC. The combined CCN and IN activity gives us valuable information on how some uncharacterized bacteria contribute to warm and mixed-phase cloud formation in the atmosphere.

  19. Synthesis and study of anti-bacterial activity of complexes of diallyldisulphide from garlic

    Directory of Open Access Journals (Sweden)

    Shashi Prabha Singh

    2012-01-01

    Full Text Available Background: The development of bacterial resistance to available antibiotics and increasing incidence of multiresistant bacterial infections in hospitals and in the community has necessitated the search for new antibacterial agents to treat the bacterial infection. It has long been known that metal ions are involved in biological processes of life through bonding to the heteroatoms of the heterocyclic residues of biological molecules i.e., proteins, enzymes and nucleic acids etc. The behavior of the disulfide group as a donor in transition metal complexes has not been subjected to such detailed study as a number of other donor groups. Aim: The Diallyldisulphide is one of the main constituents of Allium sativum (Garlic. The antibacterial and antifungal activity of the Garlic is due to the presence of sulphur containing compounds. The aim of the present work was to synthesize metal complexes with Diallyldisulphide. Materials and Methods: Complexation reactions between the Diallyldisulphide and the metal ions were carried out at three different pH i.e. acidic (pH 3, neutral (pH 7 and alkaline (pH 10 using three different ratios of metal ligand namely 1:1, 1:2, 1:3, respectively. Complex formation with the ligand and all the metals took place at pH 10, indicating that complexes were stable at this pH. Studies with different metal: ligand ratio showed that in case of silver the complexation took place at 1:1 ratio. In case of divalent metals, the appropriate ratio of metal: ligand was 1:2. The structures of the new complexes obtained were determined by spectroscopic methods. Results and Discussion: Synthesized complexes were investigated for antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae and E.coli. Diallyldisulphide-silver complex exhibited significant antibacterial activity (MIC 100 μg/ mL, and was found to be effective against selected organisms. The results concluded that the metal complexes

  20. Bacterial colonization of colonic crypt mucous gel and disease activity in ulcerative colitis.

    LENUS (Irish Health Repository)

    Rowan, Fiachra

    2012-02-01

    OBJECTIVE: To optimize total bacterial 16S rRNA quantification in microdissected colonic crypts in healthy controls and patients with ulcerative colitis (UC) and to characterize the findings with disease activity. BACKGROUND: Microscopic and molecular techniques have recently converged to allow bacterial enumeration in remote anatomic locations [eg, crypt-associated mucous gel (CAMG)]. The aims of this study were to combine laser capture microdissection (LCM) and 16S rRNA-based quantitative polymerase chain reaction (qPCR) to determine total bacterial copy number in CAMG both in health and in UC and to characterize the findings with disease activity. METHODS: LCM was used to microdissect CAMG from colonic mucosal biopsies from controls (n = 20) and patients with acute (n = 10) or subacute (n = 10) UC. Pan-bacterial 16S rRNA copy number per millimeter square in samples from 6 locations across the large bowel was obtained by qPCR using Desulfovibrio desulfuricans as a reference strain. Copy numbers were correlated with the UC disease activity index (UCDAI) and the simple clinical colitis activity index (SCCAI). RESULTS: Bacterial colonization of CAMG was detectable in all groups. Copy numbers were significantly reduced in acute UC. In subacute colitis, there was a positive correlation between copy number and UCDAI and SCCAI in the ascending, transverse and sigmoid colon. CONCLUSIONS: This study describes a sensitive method of quantitatively assessing bacterial colonization of the colonic CAMG. A positive correlation was found between CAMG bacterial load and subacute disease activity in UC, whereas detectable bacterial load was reduced in acute UC.

  1. Effect of treatment of bacterial vaginosis on disease activity in rheumatoid arthritis

    Directory of Open Access Journals (Sweden)

    M. Kalhor

    2016-06-01

    Full Text Available Background: Rheumatoid arthritis is one of the most common autoimmune diseases in women of reproductive age. Studies have shown that bacterial vaginosis can affect the activity of rheumatoid arthritis. Objective: The aim of this study was to investigate the effect of treatment of bacterial vaginosis on disease activity in rheumatoid arthritis. Methods: This interventional study was conducted in 100 women with rheumatoid arthritis (50 women with bacterial vaginosis and 50 women without bacterial vaginosis referred to the Rheumatology clinic in Tehran during 2013. The activity of rheumatoid arthritis was assessed by DAS-28 in both groups before the study. The women were treated with oral metronidazole 500 mg twice daily for one week in the intervention group. The disease activity was also assessed in both groups after the study. Data were analyzed using T-test, Chi-square test, and ANOVA. Findings: The disease activity was not significantly different between the two the groups before the study. But the disease activity in the intervention group was significantly lower than the control group after the study. Conclusion: With regards to the results, it seems that the treatment of bacterial vaginosis can improve the activity of rheumatoid arthritis. These findings indicate the importance of attention to health care in women with rheumatoid arthritis by healthcare providers.

  2. Genetic Screening for Bacterial Mutants in Liquid Growth Media By Fluorescence-Activated Cell Sorting

    Science.gov (United States)

    Abuaita, Basel H.; Withey, Jeffrey H.

    2010-01-01

    Many bacterial pathogens have defined in vitro virulence inducing conditions in liquid media which lead to production of virulence factors important during an infection. Identifying mutants that no longer respond to virulence inducing conditions will increase our understanding of bacterial pathogenesis. However, traditional genetic screens require growth on solid media. Bacteria in a single colony are in every phase of the growth curve, which complicates the analysis and make screens for growth phase-specific mutants problematic. Here, we utilize fluorescence-activated cell sorting in conjunction with random transposon mutagenesis to isolate bacteria grown in liquid media that are defective in virulence activation. This method permits analysis of an entire bacterial population in real time and selection of individual bacterial mutants with the desired gene expression profile at any time point after induction. We have used this method to identify Vibrio cholerae mutants defective in virulence induction. PMID:21094189

  3. PREVALENCE OF BACTERIAL VAGINOSIS AMONG SEXUALLY ACTIVE WOMEN ATTENDING THE CDC CENTRAL CLINIC TIKO, SOUTH WEST REGION, CAMEROON.

    Science.gov (United States)

    Achondou, Akomoneh Elvis; Fumoloh, Foche Francis; Aseneck, Aseneck Christian; Awah, Abong Ralph; Utokoro, Ajonina Marcelus

    2016-01-01

    Bacterial vaginosis (BV) is a polymicrobial, superficial vaginal infection involving a reduction in the amount of hydrogen peroxide-producing Lactobacillus and overgrowth of anaerobic bacteria. Common symptoms include increased fishy smelling vaginal discharge which is usually white or gray in color. Burning with urination may occur and itching is uncommon. Risk factors include douching, new or multiple sex partners, antibiotics, and use of intrauterine device among others. This cross-sectional study assessed the prevalence of bacterial vaginosis among sexually active women aged 15-45 years. Vaginal swabs were obtained with the use of sterile swab sticks which were later smeared on clean glass slides and then Gram stained. The stained smears were observed for bacterial morphotypes with the X100 oil immersion objective and the Nugent scoring system was used to determine BV. Data were analyzed using the Statistical Package for Social Scientists (SPSS) version 17.0 and were considered significant at p 0.05). Conclusively, the prevalence of bacterial vaginosis in our study population is 38% and highest among women aged between 25 and 34 years, pregnant women, married women, less educated women and women who practiced poor vaginal hygiene.

  4. Gut Commensal E. coli Proteins Activate Host Satiety Pathways following Nutrient-Induced Bacterial Growth.

    Science.gov (United States)

    Breton, Jonathan; Tennoune, Naouel; Lucas, Nicolas; Francois, Marie; Legrand, Romain; Jacquemot, Justine; Goichon, Alexis; Guérin, Charlène; Peltier, Johann; Pestel-Caron, Martine; Chan, Philippe; Vaudry, David; do Rego, Jean-Claude; Liénard, Fabienne; Pénicaud, Luc; Fioramonti, Xavier; Ebenezer, Ivor S; Hökfelt, Tomas; Déchelotte, Pierre; Fetissov, Sergueï O

    2016-02-09

    The composition of gut microbiota has been associated with host metabolic phenotypes, but it is not known if gut bacteria may influence host appetite. Here we show that regular nutrient provision stabilizes exponential growth of E. coli, with the stationary phase occurring 20 min after nutrient supply accompanied by bacterial proteome changes, suggesting involvement of bacterial proteins in host satiety. Indeed, intestinal infusions of E. coli stationary phase proteins increased plasma PYY and their intraperitoneal injections suppressed acutely food intake and activated c-Fos in hypothalamic POMC neurons, while their repeated administrations reduced meal size. ClpB, a bacterial protein mimetic of α-MSH, was upregulated in the E. coli stationary phase, was detected in plasma proportional to ClpB DNA in feces, and stimulated firing rate of hypothalamic POMC neurons. Thus, these data show that bacterial proteins produced after nutrient-induced E. coli growth may signal meal termination. Furthermore, continuous exposure to E. coli proteins may influence long-term meal pattern.

  5. Influence of bacterial activities on nitrogen uptake rates determined by the application of antibiotics

    Directory of Open Access Journals (Sweden)

    Clavery Tungaraza

    2003-09-01

    Full Text Available The influence of bacterial activities on inorganic nutrients has always affected total phytoplankton uptake rates owing to the absence of a reliable method that can exclude these effects. The use of natural samples to determine the contribution of bacterial activities has been based on the size fractionation method which, unfortunately, is encumbered with uncertainties, especially because of the size overlap between bacteria and phytoplankton communities. In this paper, the results are reported of an estimation of bacterial activities by the use of inhibitors (antibiotics. It was shown that the contribution of bacterial activities to the uptake of nitrogenous nutrients was highest for ammonium (79%, followed by nitrate (72% and urea (62%. In a second set of experiments the concentration of ammonium was raised by 5 µM. This was done to avoid nutrient limitation resulting from the absence of recycled nutrients following the addition of antibiotics and the maximum contribution of bacterial activity to the uptake rate of ammonium increased to 87%. It can be concluded that the use of inhibitors is a good method, a reliable alternative to the fractionation method. However, it is important to note that inhibitors can affect both phytoplankton growth and the nutrient recycling process. Our results indicate that the application of antibiotics had measurable effects not only on the target bacteria but also on the uptake behaviour of phytoplankton. Our observations were therefore limited to the period when there was no effect on the phytoplankton, as was demonstrated by a carbon protein incorporation experiment.

  6. Bacterial communities and syntrophic associations involved in anaerobic oxidation of methane process of the Sonora Margin cold seeps, Guaymas Basin.

    Science.gov (United States)

    Vigneron, Adrien; Cruaud, Perrine; Pignet, Patricia; Caprais, Jean-Claude; Gayet, Nicolas; Cambon-Bonavita, Marie-Anne; Godfroy, Anne; Toffin, Laurent

    2014-09-01

    The Sonora Margin cold seeps present on the seafloor a patchiness pattern of white microbial mats surrounded by polychaete and gastropod beds. These surface assemblages are fuelled by abundant organic inputs sedimenting from the water column and upward-flowing seep fluids. Elevated microbial density was observed in the underlying sediments. A previous study on the same samples identified anaerobic oxidation of methane (AOM) as the potential dominant archaeal process in these Sonora Margin sediments, probably catalysed by three clades of archaeal anaerobic methanotrophs (ANME-1, ANME-2 and ANME-3) associated with bacterial syntrophs. In this study, molecular surveys and microscopic observations investigating the diversity of Bacteria involved in AOM process, as well as the environmental parameters affecting the composition and the morphologies of AOM consortia in the Sonora Margin sediments were carried out. Two groups of Bacteria were identified within the AOM consortia, the Desulfosarcina/Desulfococcus SEEP SRB-1a group and a Desulfobulbus-related group. These bacteria showed different niche distributions, association specificities and consortia architectures, depending on sediment surface communities, geochemical parameters and ANME-associated phylogeny. Therefore, the syntrophic AOM process appears to depend on sulphate-reducing bacteria with different ecological niches and/or metabolisms, in a biofilm-like organic matrix. © 2013 Society for Applied Microbiology and John Wiley & Sons Ltd.

  7. Bacterial ortholog of mammalian translocator protein (TSPO with virulence regulating activity.

    Directory of Open Access Journals (Sweden)

    Annelise Chapalain

    Full Text Available The translocator protein (TSPO, previously designated as peripheral-type benzodiazepine receptor, is a protein mainly located in the outer mitochondrial membrane of eukaryotic cells. TSPO is implicated in major physiological functions and functionally associated with other proteins such as the voltage-dependent anionic channel, also designated as mitochondrial porin. Surprisingly, a TSPO-related protein was identified in the photosynthetic bacterium Rhodobacter sphaeroides but it was initially considered as a relict of evolution. In the present study we cloned a tspO gene in Pseudomonas fluorescens MF37, a non-photosynthetic eubacterium and we used bioinformatics tools to identify TSPO in the genome of 97 other bacteria. P. fluorescens TSPO was recognized by antibodies against mouse protein and by PK 11195, an artificial ligand of mitochondrial TSPO. As in eukaryotes, bacterial TSPO appears functionally organized as a dimer and the apparent Kd for PK 11195 is in the same range than for its eukaryotic counterpart. When P. fluorescens MF37 was treated with PK 11195 (10(-5 M adhesion to living or artificial surfaces and biofilm formation activity were increased. Conversely, the apoptotic potential of bacteria on eukaryotic cells was significantly reduced. This effect of PK11195 was abolished in a mutant of P. fluorescens MF37 deficient for its major outer membrane porin, OprF. The present results demonstrate the existence of a bacterial TSPO that shares common structural and functional characteristics with its mammalian counterpart. This protein, apparently involved in adhesion and virulence, reveals the existence of a possible new inter kingdom signalling system and suggests that the human microbiome should be involuntarily exposed to the evolutionary pressure of benzodiazepines and related molecules. This discovery also represents a promising opportunity for the development of alternative antibacterial strategies.

  8. Chitosan-propolis nanoparticle formulation demonstrates anti-bacterial activity against Enterococcus faecalis biofilms.

    Science.gov (United States)

    Ong, Teik Hwa; Chitra, Ebenezer; Ramamurthy, Srinivasan; Siddalingam, Rajinikanth Paruvathanahalli; Yuen, Kah Hay; Ambu, Stephen Periathamby; Davamani, Fabian

    2017-01-01

    Propolis obtained from bee hives is a natural substance with antimicrobial properties. It is limited by its insolubility in aqueous solutions; hence ethanol and ethyl acetate extracts of Malaysian propolis were prepared. Both the extracts displayed antimicrobial and anti-biofilm properties against Enterococcus faecalis, a common bacterium associated with hospital-acquired infections. High performance liquid chromatography (HPLC) analysis of propolis revealed the presence of flavonoids like kaempferol and pinocembrin. This study investigated the role of propolis developed into nanoparticles with chitosan for its antimicrobial and anti-biofilm properties against E. faecalis. Bacteria that grow in a slimy layer of biofilm are resistant to penetration by antibacterial agents. The use of nanoparticles in medicine has received attention recently due to better bioavailability, enhanced penetrative capacity and improved efficacy. A chitosan-propolis nanoformulation was chosen based on ideal physicochemical properties such as particle size, zeta potential, polydispersity index, encapsulation efficiency and the rate of release of the active ingredients. This formulation inhibited E. faecalis biofilm formation and reduced the number of bacteria in the biofilm by ~90% at 200 μg/ml concentration. When tested on pre-formed biofilms, the formulation reduced bacterial number in the biofilm by ~40% and ~75% at 200 and 300 μg/ml, respectively. The formulation not only reduced bacterial numbers, but also physically disrupted the biofilm structure as observed by scanning electron microscopy. Treatment of biofilms with chitosan-propolis nanoparticles altered the expression of biofilm-associated genes in E. faecalis. The results of this study revealed that chitosan-propolis nanoformulation can be deemed as a potential anti-biofilm agent in resisting infections involving biofilm formation like chronic wounds and surgical site infections.

  9. Chitosan-propolis nanoparticle formulation demonstrates anti-bacterial activity against Enterococcus faecalis biofilms

    Science.gov (United States)

    Ong, Teik Hwa; Chitra, Ebenezer; Ramamurthy, Srinivasan; Siddalingam, Rajinikanth Paruvathanahalli; Yuen, Kah Hay; Ambu, Stephen Periathamby

    2017-01-01

    Propolis obtained from bee hives is a natural substance with antimicrobial properties. It is limited by its insolubility in aqueous solutions; hence ethanol and ethyl acetate extracts of Malaysian propolis were prepared. Both the extracts displayed antimicrobial and anti-biofilm properties against Enterococcus faecalis, a common bacterium associated with hospital-acquired infections. High performance liquid chromatography (HPLC) analysis of propolis revealed the presence of flavonoids like kaempferol and pinocembrin. This study investigated the role of propolis developed into nanoparticles with chitosan for its antimicrobial and anti-biofilm properties against E. faecalis. Bacteria that grow in a slimy layer of biofilm are resistant to penetration by antibacterial agents. The use of nanoparticles in medicine has received attention recently due to better bioavailability, enhanced penetrative capacity and improved efficacy. A chitosan-propolis nanoformulation was chosen based on ideal physicochemical properties such as particle size, zeta potential, polydispersity index, encapsulation efficiency and the rate of release of the active ingredients. This formulation inhibited E. faecalis biofilm formation and reduced the number of bacteria in the biofilm by ~90% at 200 μg/ml concentration. When tested on pre-formed biofilms, the formulation reduced bacterial number in the biofilm by ~40% and ~75% at 200 and 300 μg/ml, respectively. The formulation not only reduced bacterial numbers, but also physically disrupted the biofilm structure as observed by scanning electron microscopy. Treatment of biofilms with chitosan-propolis nanoparticles altered the expression of biofilm-associated genes in E. faecalis. The results of this study revealed that chitosan-propolis nanoformulation can be deemed as a potential anti-biofilm agent in resisting infections involving biofilm formation like chronic wounds and surgical site infections. PMID:28362873

  10. Eggshell and Bacterial Cellulose Composite Membrane as Absorbent Material in Active Packaging

    Directory of Open Access Journals (Sweden)

    S. Ummartyotin

    2016-01-01

    Full Text Available Bacterial cellulose and eggshell composite was successfully developed. Eggshell was mixed with bacterial cellulose suspension and it was casted as a composite film. CaCO3 derived from eggshell was compared with its commercial availability. It can be noted that good dispersion of eggshell particle was prepared. Eggshell particle was irregular in shape with a variation in size. It existed in bacterial cellulose network. Characterization on composite was focused on thermal and mechanical properties. It showed that flexibility and thermal stability of composite were enhanced. No significant effect of mechanical properties was therefore observed. The thermal stability of composite was stable up to 300°C. The adsorption experiment on water and vegetable oil capacity was performed. The enhancement on adsorption was due to the existence of eggshell in bacterial cellulose composite. It exhibited the potential to be a good candidate for absorbent material in active packaging.

  11. Specific antibiotics and nematode trophic groups agree in assessing fungal:bacterial activity in agricultural soil

    DEFF Research Database (Denmark)

    Christensen, S; Dam, M; Vestergaard, M;

    2012-01-01

    There are no methods at hand with a long and proven record for assessing the relative contribution of fungi and bacteria to decomposer activity in soil. Whereas a multitude of methods to determine fungal and bacterial biomass are available, activity assays traditionally relied on the substrate...

  12. Dual action of BPC194 : a membrane active peptide killing bacterial cells

    NARCIS (Netherlands)

    Moiset, Gemma; Cirac, Anna D; Stuart, Marc C A; Marrink, Siewert-Jan; Sengupta, Durba; Poolman, Bert

    2013-01-01

    Membrane active peptides can perturb the lipid bilayer in several ways, such as poration and fusion of the target cell membrane, and thereby efficiently kill bacterial cells. We probe here the mechanistic basis of membrane poration and fusion caused by membrane-active, antimicrobial peptides. We

  13. Active stream segregation specifically involves the left human auditory cortex.

    Science.gov (United States)

    Deike, Susann; Scheich, Henning; Brechmann, André

    2010-06-14

    An important aspect of auditory scene analysis is the sequential grouping of similar sounds into one "auditory stream" while keeping competing streams separate. In the present low-noise fMRI study we presented sequences of alternating high-pitch (A) and low-pitch (B) complex harmonic tones using acoustic parameters that allow the perception of either two separate streams or one alternating stream. However, the subjects were instructed to actively and continuously segregate the A from the B stream. This was controlled by the additional instruction to listen for rare level deviants only in the low-pitch stream. Compared to the control condition in which only one non-separable stream was presented the active segregation of the A from the B stream led to a selective increase of activation in the left auditory cortex (AC). Together with a similar finding from a previous study using a different acoustic cue for streaming, namely timbre, this suggests that the left auditory cortex plays a dominant role in active sequential stream segregation. However, we found cue differences within the left AC: Whereas in the posterior areas, including the planum temporale, activation increased for both acoustic cues, the anterior areas, including Heschl's gyrus, are only involved in stream segregation based on pitch.

  14. Subunit-selective proteasome activity profiling uncovers uncoupled proteasome subunit activities during bacterial infections

    NARCIS (Netherlands)

    Misas-villamil, Johana C.; Burgh, Van Der Aranka M.; Grosse-holz, Friederike; Bach-pages, Marcel; Kovács, Judit; Kaschani, Farnusch; Schilasky, Sören; Emon, Asif E.K.; Ruben, Mark; Kaiser, Markus; Overkleeft, Hermen S.; Hoorn, van der Renier A.L.

    2017-01-01

    The proteasome is a nuclear-cytoplasmic proteolytic complex involved in nearly all regulatory pathways in plant cells. The three different catalytic activities of the proteasome can have different functions, but tools to monitor and control these subunits selectively are not yet available in plant

  15. Bacterial proteases and virulence

    DEFF Research Database (Denmark)

    Frees, Dorte; Brøndsted, Lone; Ingmer, Hanne

    2013-01-01

    Bacterial pathogens rely on proteolysis for variety of purposes during the infection process. In the cytosol, the main proteolytic players are the conserved Clp and Lon proteases that directly contribute to virulence through the timely degradation of virulence regulators and indirectly by providing....... These extracellular proteases are activated in complex cascades involving auto-processing and proteolytic maturation. Thus, proteolysis has been adopted by bacterial pathogens at multiple levels to ensure the success of the pathogen in contact with the human host....

  16. Distribution of bacterial growth activity in flow-chamber biofilms

    DEFF Research Database (Denmark)

    Sternberg, Claus; Christensen, Bjarke B.; Johansen, Tove;

    1999-01-01

    In microbial communities such as those found in biofilms, individual organisms most often display heterogeneous behavior with respect to their metabolic activity, growth status, gene expression pattern, etc. In that context, a novel reporter system for monitoring of cellular growth activity has...... been designed. It comprises a transposon cassette carrying fusions between the growth rate-regulated Escherichia coli rrnBP1 promoter and different variant gfp genes. It is shown that the pi promoter is regulated in the same way in E. coli and Pseudomonas putida, making it useful for monitoring...... of growth activity in organisms outside the group of enteric bacteria. Construction of fusions to genes encoding unstable Gfp proteins opened up the possibility of the monitoring of rates of rRNA synthesis and, in this way, allowing on-line determination of the distribution of growth activity in a complex...

  17. Denitrification, activity of bacterial flocs, and growth of a filamentous bacterium in relation with the bulking of activated sludge

    NARCIS (Netherlands)

    Krul, J.M.

    1978-01-01

    Activated sludge with poor settling characteristics is caught under the term "bulking" sludge. Various types of bulking activated sludge can be distinguished.1) Sludge containing an abundance of filamentous microorganisms.2) Sludge, characterized by excessive amount of bacterial slime.3) Flotating s

  18. Diversity of Dominant Bacterial Taxa in Activated Sludge Promotes Functional Resistance following Toxic Shock Loading

    KAUST Repository

    Saikaly, Pascal

    2010-12-14

    Examining the relationship between biodiversity and functional stability (resistance and resilience) of activated sludge bacterial communities following disturbance is an important first step towards developing strategies for the design of robust biological wastewater treatment systems. This study investigates the relationship between functional resistance and biodiversity of dominant bacterial taxa by subjecting activated sludge samples, with different levels of biodiversity, to toxic shock loading with cupric sulfate (Cu[II]), 3,5-dichlorophenol (3,5-DCP), or 4-nitrophenol (4-NP). Respirometric batch experiments were performed to determine the functional resistance of activated sludge bacterial community to the three toxicants. Functional resistance was estimated as the 30 min IC50 or the concentration of toxicant that results in a 50% reduction in oxygen utilization rate compared to a referential state represented by a control receiving no toxicant. Biodiversity of dominant bacterial taxa was assessed using polymerase chain reaction-terminal restriction fragment length polymorphism (PCR-T-RFLP) targeting the 16S ribosomal RNA (16S rRNA) gene. Statistical analysis of 30 min IC50 values and PCR-T-RFLP data showed a significant positive correlation (P<0.05) between functional resistance and microbial diversity for each of the three toxicants tested. To our knowledge, this is the first study showing a positive correlation between biodiversity of dominant bacterial taxa in activated sludge and functional resistance. In this system, activated sludge bacterial communities with higher biodiversity are functionally more resistant to disturbance caused by toxic shock loading. © 2010 Springer Science+Business Media, LLC.

  19. Effects of opsonization of Rhodococcus equi on bacterial viability and phagocyte activation.

    Science.gov (United States)

    Dawson, Dominic R; Nydam, Daryl V; Price, Christopher T; Graham, James E; Cynamon, Michael H; Divers, Thomas J; Felippe, Maria Julia B

    2011-11-01

    To investigate the effect of opsonization of Rhodococcus equi with R. equi-specific antibodies in plasma on bacterial viability and phagocyte activation in a cell culture model of infection. Neutrophils and monocyte-derived macrophages from 6 healthy 1-week-old foals and 1 adult horse. Foal and adult horse phagocytes were incubated with either opsonized or nonopsonized bacteria. Opsonization was achieved by use of plasma containing high or low concentrations of R. equi-specific antibodies. Phagocyte oxidative burst activity was measured by use of flow cytometry, and macrophage tumor necrosis factor (TNF)-α production was measured via an ELISA. Extracellular and intracellular bacterial viability was measured with a novel R. equi-luciferase construct that used a luminometer. Opsonized bacteria increased oxidative burst activity in adult horse phagocytes, and neutrophil activity was dependent on the concentration of specific antibody. Secretion of TNF-α was higher in macrophages infected with opsonized bacteria. Opsonization had no significant effect on bacterial viability in macrophages; however, extracellular bacterial viability was decreased in broth containing plasma with R. equi-specific antibodies, compared with viability in broth alone. The use of plasma enriched with specific antibodies for the opsonization of R. equi increased the activation of phagocytes and decreased bacterial viability in the extracellular space. Although opsonized R. equi increased TNF-α secretion and oxidative burst in macrophages, additional factors may be necessary for effective intracellular bacterial killing. These data have suggested a possible role of plasma antibody in protection of foals from R. equi pneumonia.

  20. Common mechanisms involved in Alzheimer's disease and type 2 diabetes: a key role of chronic bacterial infection and inflammation.

    Science.gov (United States)

    Miklossy, Judith; McGeer, Patrick L

    2016-04-01

    Strong epidemiologic evidence and common molecular mechanisms support an association between Alzheimer's disease (AD) and type 2-diabetes. Local inflammation and amyloidosis occur in both diseases and are associated with periodontitis and various infectious agents. This article reviews the evidence for the presence of local inflammation and bacteria in type 2 diabetes and discusses host pathogen interactions in chronic inflammatory disorders. Chlamydophyla pneumoniae, Helicobacter pylori and spirochetes are demonstrated in association with dementia and brain lesions in AD and islet lesions in type 2 diabetes. The presence of pathogens in host tissues activates immune responses through Toll-like receptor signaling pathways. Evasion of pathogens from complement-mediated attack results in persistent infection, inflammation and amyloidosis. Amyloid beta and the pancreatic amyloid called amylin bind to lipid bilayers and produce Ca(2+) influx and bacteriolysis. Similarly to AD, accumulation of amylin deposits in type 2 diabetes may result from an innate immune response to chronic bacterial infections, which are known to be associated with amyloidosis. Further research based on an infectious origin of both AD and type 2 diabetes may lead to novel treatment strategies.

  1. Bacterial Vaginosis

    Science.gov (United States)

    ... Issues > Conditions > Sexually Transmitted > Bacterial Vaginosis Health Issues Listen Español Text Size Email Print Share Bacterial Vaginosis Page Content Bacterial vaginosis (BV) is the most common vaginal infection in sexually active teenaged girls . It appears to be caused by ...

  2. Profiling bacterial kinase activity using a genetic circuit

    DEFF Research Database (Denmark)

    van der Helm, Eric; Bech, Rasmus; Lehning, Christina Eva

    Phosphorylation is a post-translational modification that regulates the activity of several key proteins in bacteria and eukaryotes. Accordingly, a variety of tools has been developed to measure kinase activity. To couple phosphorylation to an in vivo fluorescent readout we used the Bacillus...... subtilis kinase PtkA, transmembrane activator TkmA and the repressor FatR to construct a genetic circuit in E. coli. By tuning the repressor and kinase expression level at the same time, we were able to show a 4.2-fold increase in signal upon kinase induction. We furthermore validated that the previously...... reported FatR Y45E mutation1 attenuates operator repression. This genetic circuit provides a starting point for computational protein design and a metagenomic library-screening tool....

  3. Probiotic Activity of a Bacterial Strain Isolated from Ancient Permafrost Against Salmonella Infection in Mice.

    Science.gov (United States)

    Fursova, O; Potapov, V; Brouchkov, A; Pogorelko, G; Griva, G; Fursova, N; Ignatov, S

    2012-09-01

    Bacillus cereus strain F, collected from relict permafrost located in Siberia, was analyzed for probiotic activity in the mouse Salmonella enterica model. Viable bacterial cells were found in frozen soils taken at Mammoth Mountain in Yakutia from a depth below the level of seasonal thawing. Geological data indicated the absence of a thawing within millions of years of deposited soils, which helped to ensure the ancient origin of our sample. According to DNA analysis, bacterial cells collected from the relict permafrost appeared to be B. cereus strain F. The morphology of these bacteria was analyzed using atomic force microscopy. B. cereus strain F was assessed as a nonpathogenic bacterium by evaluation of its pathogenicity. A S. enterica model is described in mice after per oral inoculation and serves as a model for the human carrier state. Using this model, probiotic activity by the bacterial strain isolated from the ancient permafrost has been shown against Salmonella infection in mice.

  4. Bacterial lipopolysaccharide promotes profibrotic activation of intestinal fibroblasts.

    LENUS (Irish Health Repository)

    Burke, J P

    2012-02-01

    BACKGROUND: Fibroblasts play a critical role in intestinal wound healing. Lipopolysaccharide (LPS) is a cell wall component of commensal gut bacteria. The effects of LPS on intestinal fibroblast activation were characterized. METHODS: Expression of the LPS receptor, toll-like receptor (TLR) 4, was assessed in cultured primary human intestinal fibroblasts using flow cytometry and confocal microscopy. Fibroblasts were treated with LPS and\\/or transforming growth factor (TGF) beta1. Nuclear factor kappaB (NFkappaB) pathway activation was assessed by inhibitory kappaBalpha (IkappaBalpha) degradation and NFkappaB promoter activity. Fibroblast contractility was measured using a fibroblast-populated collagen lattice. Smad-7, a negative regulator of TGF-beta1 signalling, and connective tissue growth factor (CTGF) expression were assessed using reverse transcriptase-polymerase chain reaction and western blot. The NFkappaB pathway was inhibited by IkappaBalpha transfection. RESULTS: TLR-4 was present on the surface of intestinal fibroblasts. LPS treatment of fibroblasts induced IkappaBalpha degradation, enhanced NFkappaB promoter activity and increased collagen contraction. Pretreatment with LPS (before TGF-beta1) significantly increased CTGF production relative to treatment with TGF-beta1 alone. LPS reduced whereas TGF-beta1 increased smad-7 expression. Transfection with an IkappaBalpha plasmid enhanced basal smad-7 expression. CONCLUSION: Intestinal fibroblasts express TLR-4 and respond to LPS by activating NFkappaB and inducing collagen contraction. LPS acts in concert with TGF-beta1 to induce CTGF. LPS reduces the expression of the TGF-beta1 inhibitor, smad-7.

  5. Structure and function of Helicobacter pylori CagA, the first-identified bacterial protein involved in human cancer

    National Research Council Canada - National Science Library

    HATAKEYAMA, Masanori

    2017-01-01

    .... The cagA gene-encoded CagA protein is delivered into gastric epithelial cells via bacterial type IV secretion, where it undergoes tyrosine phosphorylation at the Glu-Pro-Ile-Tyr-Ala (EPIYA) motifs...

  6. Soil-borne bacterial structure and diversity does not reflect community activity in Pampa biome.

    Directory of Open Access Journals (Sweden)

    Manoeli Lupatini

    Full Text Available The Pampa biome is considered one of the main hotspots of the world's biodiversity and it is estimated that half of its original vegetation was removed and converted to agricultural land and tree plantations. Although an increasing amount of knowledge is being assembled regarding the response of soil bacterial communities to land use change, to the associated plant community and to soil properties, our understanding about how these interactions affect the microbial community from the Brazilian Pampa is still poor and incomplete. In this study, we hypothesized that the same soil type from the same geographic region but under distinct land use present dissimilar soil bacterial communities. To test this hypothesis, we assessed the soil bacterial communities from four land-uses within the same soil type by 454-pyrosequencing of 16S rRNA gene and by soil microbial activity analyzes. We found that the same soil type under different land uses harbor similar (but not equal bacterial communities and the differences were controlled by many microbial taxa. No differences regarding diversity and richness between natural areas and areas under anthropogenic disturbance were detected. However, the measures of microbial activity did not converge with the 16S rRNA data supporting the idea that the coupling between functioning and composition of bacterial communities is not necessarily correlated.

  7. Soil-borne bacterial structure and diversity does not reflect community activity in Pampa biome.

    Science.gov (United States)

    Lupatini, Manoeli; Suleiman, Afnan Khalil Ahmad; Jacques, Rodrigo Josemar Seminoti; Antoniolli, Zaida Inês; Kuramae, Eiko Eurya; de Oliveira Camargo, Flávio Anastácio; Roesch, Luiz Fernando Würdig

    2013-01-01

    The Pampa biome is considered one of the main hotspots of the world's biodiversity and it is estimated that half of its original vegetation was removed and converted to agricultural land and tree plantations. Although an increasing amount of knowledge is being assembled regarding the response of soil bacterial communities to land use change, to the associated plant community and to soil properties, our understanding about how these interactions affect the microbial community from the Brazilian Pampa is still poor and incomplete. In this study, we hypothesized that the same soil type from the same geographic region but under distinct land use present dissimilar soil bacterial communities. To test this hypothesis, we assessed the soil bacterial communities from four land-uses within the same soil type by 454-pyrosequencing of 16S rRNA gene and by soil microbial activity analyzes. We found that the same soil type under different land uses harbor similar (but not equal) bacterial communities and the differences were controlled by many microbial taxa. No differences regarding diversity and richness between natural areas and areas under anthropogenic disturbance were detected. However, the measures of microbial activity did not converge with the 16S rRNA data supporting the idea that the coupling between functioning and composition of bacterial communities is not necessarily correlated.

  8. Structural and dynamic requirements for optimal activity of the essential bacterial enzyme dihydrodipicolinate synthase.

    Directory of Open Access Journals (Sweden)

    C F Reboul

    Full Text Available Dihydrodipicolinate synthase (DHDPS is an essential enzyme involved in the lysine biosynthesis pathway. DHDPS from E. coli is a homotetramer consisting of a 'dimer of dimers', with the catalytic residues found at the tight-dimer interface. Crystallographic and biophysical evidence suggest that the dimers associate to stabilise the active site configuration, and mutation of a central dimer-dimer interface residue destabilises the tetramer, thus increasing the flexibility and reducing catalytic efficiency and substrate specificity. This has led to the hypothesis that the tetramer evolved to optimise the dynamics within the tight-dimer. In order to gain insights into DHDPS flexibility and its relationship to quaternary structure and function, we performed comparative Molecular Dynamics simulation studies of native tetrameric and dimeric forms of DHDPS from E. coli and also the native dimeric form from methicillin-resistant Staphylococcus aureus (MRSA. These reveal a striking contrast between the dynamics of tetrameric and dimeric forms. Whereas the E. coli DHDPS tetramer is relatively rigid, both the E. coli and MRSA DHDPS dimers display high flexibility, resulting in monomer reorientation within the dimer and increased flexibility at the tight-dimer interface. The mutant E. coli DHDPS dimer exhibits disorder within its active site with deformation of critical catalytic residues and removal of key hydrogen bonds that render it inactive, whereas the similarly flexible MRSA DHDPS dimer maintains its catalytic geometry and is thus fully functional. Our data support the hypothesis that in both bacterial species optimal activity is achieved by fine tuning protein dynamics in different ways: E. coli DHDPS buttresses together two dimers, whereas MRSA dampens the motion using an extended tight-dimer interface.

  9. Structural and Dynamic Requirements for Optimal Activity of the Essential Bacterial Enzyme Dihydrodipicolinate Synthase

    Science.gov (United States)

    Reboul, C. F.; Porebski, B. T.; Griffin, M. D. W.; Dobson, R. C. J.; Perugini, M. A.; Gerrard, J. A.; Buckle, A. M.

    2012-01-01

    Dihydrodipicolinate synthase (DHDPS) is an essential enzyme involved in the lysine biosynthesis pathway. DHDPS from E. coli is a homotetramer consisting of a ‘dimer of dimers’, with the catalytic residues found at the tight-dimer interface. Crystallographic and biophysical evidence suggest that the dimers associate to stabilise the active site configuration, and mutation of a central dimer-dimer interface residue destabilises the tetramer, thus increasing the flexibility and reducing catalytic efficiency and substrate specificity. This has led to the hypothesis that the tetramer evolved to optimise the dynamics within the tight-dimer. In order to gain insights into DHDPS flexibility and its relationship to quaternary structure and function, we performed comparative Molecular Dynamics simulation studies of native tetrameric and dimeric forms of DHDPS from E. coli and also the native dimeric form from methicillin-resistant Staphylococcus aureus (MRSA). These reveal a striking contrast between the dynamics of tetrameric and dimeric forms. Whereas the E. coli DHDPS tetramer is relatively rigid, both the E. coli and MRSA DHDPS dimers display high flexibility, resulting in monomer reorientation within the dimer and increased flexibility at the tight-dimer interface. The mutant E. coli DHDPS dimer exhibits disorder within its active site with deformation of critical catalytic residues and removal of key hydrogen bonds that render it inactive, whereas the similarly flexible MRSA DHDPS dimer maintains its catalytic geometry and is thus fully functional. Our data support the hypothesis that in both bacterial species optimal activity is achieved by fine tuning protein dynamics in different ways: E. coli DHDPS buttresses together two dimers, whereas MRSA dampens the motion using an extended tight-dimer interface. PMID:22685390

  10. Bacterial community analysis of activated sludge: an evaluation of four commonly used DNA extraction methods

    NARCIS (Netherlands)

    Vanysacker, L.; Declerck, S.A.J.; Hellemans, B.; De Meester, L.; Vankelecom, I.; Declerck, P.

    2010-01-01

    The effectiveness of three commercially available direct DNA isolation kits (Mobio, Fast, Qiagen) and one published direct DNA extraction protocol (Bead) for extracting bacterial DNA from different types of activated sludge was investigated and mutually compared. The DNA quantity and purity were

  11. Bacterial community analysis of activated sludge: an evaluation of four commonly used DNA extraction methods

    NARCIS (Netherlands)

    Vanysacker, L.; Declerck, S.A.J.; Hellemans, B.; De Meester, L.; Vankelecom, I.; Declerck, P.

    2010-01-01

    The effectiveness of three commercially available direct DNA isolation kits (Mobio, Fast, Qiagen) and one published direct DNA extraction protocol (Bead) for extracting bacterial DNA from different types of activated sludge was investigated and mutually compared. The DNA quantity and purity were det

  12. Bacterial membrane activity of a-peptide/b-peptoid chimeras: Influence of amino acid composition and chain length on the activity against different bacterial strains

    DEFF Research Database (Denmark)

    Hein-Kristensen, Line; Knapp, Kolja M; Franzyk, Henrik;

    2011-01-01

    , and this was parallel by the largest reduction in number of viable bacteria. CONCLUSION: We found that chain length but not type of cationic amino acid influenced the antibacterial activity of a series of synthetic α-peptide/β-peptoid chimeras. The synthetic chimeras exert their killing effect by permeabilization......BACKGROUND: Characterization and use of antimicrobial peptides (AMPs) requires that their mode of action is determined. The interaction of membrane-active peptides with their target is often established using model membranes, however, the actual permeabilization of live bacterial cells...... acid only had a minor effect on MIC values, whereas chain length had a profound influence on activity. All chimeras were less active against Serratia marcescens (MICs above 46 μM). The chimeras were bactericidal and induced leakage of ATP from Staphylococcus aureus and S. marcescens with similar time...

  13. Anti-bacterial activity of Achatina CRP and its mechanism of action.

    Science.gov (United States)

    Mukherjee, Sandip; Barman, Soma; Mandal, Narayan Chandra; Bhattacharya, Shelley

    2014-07-01

    The physiological role of C-reactive protein (CRP), the classical acute-phase protein, is not well documented, despite many reports on biological effects of CRP in vitro and in model systems in vivo. It has been suggested that CRP protects mice against lethal toxicity of bacterial infections by implementing immunological responses. In Achatina fulica CRP is a constitutive multifunctional protein in haemolymph and considered responsible for their survival in the environment for millions of years. The efficacy of Achatina CRP (ACRP) was tested against both Salmonella typhimurium and Bacillus subtilis infections in mice where endogenous CRP level is negligible even after inflammatory stimulus. Further, growth curves of the bacteria revealed that ACRP (50 microg/mL) is bacteriostatic against gram negative salmonellae and bactericidal against gram positive bacilli. ACRP induced energy crises in bacterial cells, inhibited key carbohydrate metabolic enzymes such as phosphofructokinase in glycolysis, isocitrate dehydrogenase in TCA cycle, isocitrate lyase in glyoxylate cycle and fructose-1,6-bisphosphatase in gluconeogenesis. ACRP disturbed the homeostasis of cellular redox potential as well as reduced glutathione status, which is accompanied by an enhanced rate of lipid peroxidation. Annexin V-Cy3/CFDA dual staining clearly showed ACRP induced apoptosis-like death in bacterial cell population. Moreover, immunoblot analyses also indicated apoptosis-like death in ACRP treated bacterial cells, where activation of poly (ADP-ribose) polymerase-1 (PARP) and caspase-3 was noteworthy. It is concluded that metabolic impairment by ACRP in bacterial cells is primarily due to generation of reactive oxygen species and ACRP induced anti-bacterial effect is mediated by metabolic impairment leading to apoptosis-like death in bacterial cells.

  14. Differential activation of RAGE by HMGB1 modulates neutrophil-associated NADPH oxidase activity and bacterial killing.

    Science.gov (United States)

    Tadié, Jean-Marc; Bae, Hong-Beom; Banerjee, Sami; Zmijewski, Jaroslaw W; Abraham, Edward

    2012-01-01

    The receptor for advanced glycation end products (RAGE) plays an important role in host defense against bacterial infection. In the present experiments, we investigated the mechanisms by which RAGE contributes to the ability of neutrophils to eradicate bacteria. Wild-type (RAGE(+/+)) neutrophils demonstrated significantly greater ability to kill Escherichia coli compared with RAGE(-/-) neutrophils. After intraperitoneal injection of E. coli, increased numbers of bacteria were found in the peritoneal fluid from RAGE(-/-) as compared with RAGE(+/+) mice. Exposure of neutrophils to the protypical RAGE ligand AGE resulted in activation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and enhanced killing of E. coli, and intraperitoneal injection of AGE enhanced bacterial clearance during peritonitis. However, incubation of neutrophils with high mobility group box 1 protein (HMGB1), which also binds to RAGE, diminished E. coli-induced activation of NADPH oxidase in neutrophils and bacterial killing both in vitro and in vivo. Deletion of the COOH-terminal tail of HMGB1, a region necessary for binding to RAGE, abrogated the ability of HMGB1 to inhibit bacterial killing. Incubation of neutrophils with HMGB1 diminished bacterial or AGE-dependent activation of NADPH oxidase. The increase in phosphorylation of the p40(phox) subunit of NADPH oxidase that occurred after culture of neutrophils with E. coli was inhibited by exposure of the cells to HMGB1. These results showing that HMGB1, through RAGE-dependent mechanisms, diminishes bacterial killing by neutrophils as well as NADPH oxidase activation provide a novel mechanism by which HMGB1 can potentiate sepsis-associated organ dysfunction and mortality.

  15. Should Ecosystem Management Involve Active Control of Species Abundances?

    Directory of Open Access Journals (Sweden)

    Timothy E. Essington

    2005-12-01

    Full Text Available We review four case studies in which there is a risk of extinction or severe reduction in highly valued species if we ignore either, or both, of two ecosystem control options. “Symptomatic control” implies direct control of extinction risk through direct harvesting or culling of competitors and predators. “Systemic control” implies treating the causes of the problem that led to an unnaturally high abundance in the first place. We demonstrate, with a discussion of historically observed population trends, how surprising trophic interactions can emerge as a result of alterations to a system. Simulation models were developed for two of the case studies as aids to adaptive policy design, to expose possible abundance changes caused by trophic interactions and to highlight key uncertainties about possible responses to ecosystem management policies involving active intervention to control abundances. With reasonable parameter values, these models predict a wide range of possible responses given available data, but do indicate a good chance that active control would reverse declines and reverse extinction risks. We find that controlling seal (Phoca vitulina populations in the Georgia Strait increases juvenile survival rates of commercial salmon (Oncorhynchus spp. species, but that commensurate increases in hake populations from decreased seal predation could be a compensatory source of predation on juvenile salmon. We also show that wolf (Canis lupus control and moose (Alces alces harvest bring about a recovery in caribou (Rangifer tarandus caribou populations, where simple habitat protection policies fail to recover caribou before wolf predation causes severe declines. The results help address a common problem in disturbed ecosystems, where controlling extinction risks can mean choosing between active control of species abundance or establishing policies of protection, and allowing threatened species to recover naturally.

  16. Bacterial community composition and chitinase gene diversity of vermicompost with antifungal activity.

    Science.gov (United States)

    Yasir, Muhammad; Aslam, Zubair; Kim, Seon Won; Lee, Seon-Woo; Jeon, Che Ok; Chung, Young Ryun

    2009-10-01

    Bacterial communities and chitinase gene diversity of vermicompost (VC) were investigated to clarify the influence of earthworms on the inhibition of plant pathogenic fungi in VC. The spore germination of Fusarium moniliforme was reduced in VC aqueous extracts prepared from paper sludge and dairy sludge (fresh sludge, FS). The bacterial communities were examined by culture-dependent and -independent analyses. Unique clones selected from 16S rRNA libraries of FS and VC on the basis of restriction fragment length polymorphism (RFLP) fell into the major lineages of the domain bacteria Proteobacteria, Bacteroidetes, Verrucomicrobia, Actinobacteria and Firmicutes. Among culture isolates, Actinobacteria dominated in VC, while almost equal numbers of Actinobacteria and Proteobacteria were present in FS. Analysis of chitinolytic isolates and chitinase gene diversity revealed that chitinolytic bacterial communities were enriched in VC. Populations of bacteria that inhibited plant fungal pathogens were higher in VC than in FS and particularly chitinolytic isolates were most active against the target fungi.

  17. Zymomonas mobilis Levan is Involved in Metalloproteinases Activation in Healing of Wounded and Burned Tissues

    Directory of Open Access Journals (Sweden)

    Cristina Sturzoiu

    2011-05-01

    Full Text Available Healing of burn tissue is a complete process involving reepitelization, granulation tissue formation and extracellular matrix remodeling. Thermal injury produces profound systemic changes, such as oligemic shock, anemia, renal failure and metabolic disorders. This causes direct tissue damages: inflammation and infection reactions. The tissue lesion also leads to increased oxidative stress in cells, as it has been observed by the low activity of endogenous antioxidant enzymatic and nonenzymatic systems. In this context, tissue matrix metalloproteinases (MMP plays a key role in normal physiology of conjunctive tissue during its development, morphogenesis or wound healing, having an irregular activity and being involved in the patho-physiological processes. The analysis of biological samples, MMP profiles contribute to the characterization of some processes involving tissue remodeling, processes related to wound or burn healing, possibly to the development of new therapies. In this context we studied the proliferative effect of levan, a polysaccharide produced by Gram negative bacteria, Zymomonas mobilis, a microorganism that plays an important role in modern biotechnology to produce substances of great interest in biotechnology, food industry or in biomedicine. Our studies focused on analysis of tissue MMPs profiles from Wistar rats with lesions caused by mechanic processes on skin (wounds and thermal (burn, treated by hallotherapy inCacica and Dej salt mines, before and after the treatment with levan. The results indicate that levan, a natural polysaccharide produced by wild type Z. mobilis NCIB 11163, as well as other bacterial strains, seems to have real value in the management of wounds and burns, applied individually or in combination with natural or artificial haloteraphy. The way that levan participates in the healing process is unknown, probably by activating the tissue metalloproteinases.

  18. Highly bacterial resistant silver nanoparticles: synthesis and antibacterial activities

    Energy Technology Data Exchange (ETDEWEB)

    Chudasama, Bhupendra, E-mail: bnchudasama@gmail.co [Thapar University, School of Physics and Materials Science (India); Vala, Anjana K.; Andhariya, Nidhi; Mehta, R. V. [Bhavnagar University, Department of Physics (India); Upadhyay, R. V. [Charotar University of Science and Technology, P.D. Patel Institute of Applied Sciences (India)

    2010-06-15

    In this article, we describe a simple one-pot rapid synthesis route to produce uniform silver nanoparticles by thermal reduction of AgNO{sub 3} using oleylamine as reducing and capping agent. To enhance the dispersal ability of as-synthesized hydrophobic silver nanoparticles in water, while maintaining their unique properties, a facile phase transfer mechanism has been developed using biocompatible block co-polymer pluronic F-127. Formation of silver nanoparticles is confirmed by X-ray diffraction (XRD), transmission electron microscopy (TEM) and UV-vis spectroscopy. Hydrodynamic size and its distribution are obtained from dynamic light scattering (DLS). Hydrodynamic size and size distribution of as-synthesized and phase transferred silver nanoparticles are 8.2 {+-} 1.5 nm ({sigma} = 18.3%) and 31.1 {+-} 4.5 nm ({sigma} = 14.5%), respectively. Antimicrobial activities of hydrophilic silver nanoparticles is tested against two Gram positive (Bacillus megaterium and Staphylococcus aureus), and three Gram negative (Escherichiacoli, Proteusvulgaris and Shigellasonnei) bacteria. Minimum inhibitory concentration (MIC) values obtained in the present study for the tested microorganisms are found much better than those reported for commercially available antibacterial agents.

  19. Human caspase-4 mediates noncanonical inflammasome activation against gram-negative bacterial pathogens

    Science.gov (United States)

    Casson, Cierra N.; Yu, Janet; Reyes, Valeria M.; Taschuk, Frances O.; Yadav, Anjana; Copenhaver, Alan M.; Nguyen, Hieu T.; Collman, Ronald G.; Shin, Sunny

    2015-01-01

    Inflammasomes are critical for host defense against bacterial pathogens. In murine macrophages infected by gram-negative bacteria, the canonical inflammasome activates caspase-1 to mediate pyroptotic cell death and release of IL-1 family cytokines. Additionally, a noncanonical inflammasome controlled by caspase-11 induces cell death and IL-1 release. However, humans do not encode caspase-11. Instead, humans encode two putative orthologs: caspase-4 and caspase-5. Whether either ortholog functions similar to caspase-11 is poorly defined. Therefore, we sought to define the inflammatory caspases in primary human macrophages that regulate inflammasome responses to gram-negative bacteria. We find that human macrophages activate inflammasomes specifically in response to diverse gram-negative bacterial pathogens that introduce bacterial products into the host cytosol using specialized secretion systems. In primary human macrophages, IL-1β secretion requires the caspase-1 inflammasome, whereas IL-1α release and cell death are caspase-1–independent. Instead, caspase-4 mediates IL-1α release and cell death. Our findings implicate human caspase-4 as a critical regulator of noncanonical inflammasome activation that initiates defense against bacterial pathogens in primary human macrophages. PMID:25964352

  20. Synthesis and Anti-Bacterial Activities of Some Novel Schiff Bases Derived from Aminophenazone

    Directory of Open Access Journals (Sweden)

    Salman A Khan

    2010-10-01

    Full Text Available A series of 1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one-containing Schiff bases were synthesized, characterized and screened for their antibacterial activities. The structures of the synthesized compounds were established by spectroscopic (FT-IR, 1H-NMR, 13C-NMR, MS and elemental analyses. The anti-bacterial activities (with MIC values of compounds were evaluated. The anti-bacterial screening results reveal that among the six compounds screened, four compounds showed moderate to good anti-bacterial activity. Among the tested compounds, the most effective compounds against four bacterial strains, viz. Escherichia coli, Staphylococcus aureus, Salmonella typhimurium and Streptococcus pyogenes, are [(2-Chlorobenzylideneamino]-1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one (4 and [(1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yliminomethyl]benzonitrile (5 with MIC values of 6.25 μg/mL.

  1. A Host-Produced Autoinducer-2 Mimic Activates Bacterial Quorum Sensing.

    Science.gov (United States)

    Ismail, Anisa S; Valastyan, Julie S; Bassler, Bonnie L

    2016-04-13

    Host-microbial symbioses are vital to health; nonetheless, little is known about the role crosskingdom signaling plays in these relationships. In a process called quorum sensing, bacteria communicate with one another using extracellular signal molecules called autoinducers. One autoinducer, AI-2, is proposed to promote interspecies bacterial communication, including in the mammalian gut. We show that mammalian epithelia produce an AI-2 mimic activity in response to bacteria or tight-junction disruption. This AI-2 mimic is detected by the bacterial AI-2 receptor, LuxP/LsrB, and can activate quorum-sensing-controlled gene expression, including in the enteric pathogen Salmonella typhimurium. AI-2 mimic activity is induced when epithelia are directly or indirectly exposed to bacteria, suggesting that a secreted bacterial component(s) stimulates its production. Mutagenesis revealed genes required for bacteria to both detect and stimulate production of the AI-2 mimic. These findings uncover a potential role for the mammalian AI-2 mimic in fostering crosskingdom signaling and host-bacterial symbioses.

  2. Preclinical evaluation of Luffa operculata Cogn. and its main active principle in the treatment of bacterial rhinosinusitis.

    Science.gov (United States)

    Silva, Leonardo; Costa, Henrique Olival; Souza, Flávia Coelho de; Lopes, Elaine Monteiro Cardoso; Ueda, Suely Mitoi Ykko

    2016-12-26

    The prevalence of rhinosinusitis is quite high. Despite the widespread use of antibiotics for rhinosinusitis, there are other forms of treatment, including phytotherapy. One of the most widely used herbal medicines for treatment of rhinosinusitis is Luffa operculata. This study aimed to evaluate the efficacy of topical nasal solution of the aqueous extract of L. operculata, determining the toxicity to its use and identifying the active principles presented in the aqueous extract. The secondary objective was to evaluate the action of active principles on bacteria commonly involved in acute rhino sinusitis. The study was conducted in experimental model of sinusitis. Three different concentrations of L. operculata were used as local treatment of rhino sinusitis. The results were compared with those observed in control groups that received nasal saline solution. Histological examination of the liver, kidney, spleen, myocardium, brain and lungs of all animals evaluated the toxicity of L. operculata. The aqueous extract used was subjected to chromatographic analysis and an active principle was isolated and tested for in vitro inhibition of bacterial colonies usually found in rhino sinusitis. Intranasal treatment of sinusitis with L. operculata showed better clinical evolution than control group. Statistically significant difference (p>0.10) between the treated group and the control group was observed in the histologic evaluation for inflammatory pattern. The aqueous extract of L. operculata used presented a predominance of 2,3-dicafeoilglicaric acid, a substance not yet described in the literature. There was a significant difference in bacterial growth of Streptococcus pyogenes on blood-agar plates when under the influence of both the aqueous extract and the active substance. Topical nasal solution of the aqueous extract of L. operculata is effective compared to the application of saline solution for the treatment of bacterial rhinosinusitis in an experimental model. L

  3. A three-scale analysis of bacterial communities involved in rocks colonization and soil formation in high mountain environments.

    Science.gov (United States)

    Esposito, Alfonso; Ciccazzo, Sonia; Borruso, Luigimaria; Zerbe, Stefan; Daffonchio, Daniele; Brusetti, Lorenzo

    2013-10-01

    Alpha and beta diversities of the bacterial communities growing on rock surfaces, proto-soils, riparian sediments, lichen thalli, and water springs biofilms in a glacier foreland were studied. We used three molecular based techniques to allow a deeper investigation at different taxonomic resolutions: denaturing gradient gel electrophoresis, length heterogeneity-PCR, and automated ribosomal intergenic spacer analysis. Bacterial communities were mainly composed of Acidobacteria, Proteobacteria, and Cyanobacteria with distinct variations among sites. Proteobacteria were more represented in sediments, biofilms, and lichens; Acidobacteria were mostly found in proto-soils; and Cyanobacteria on rocks. Firmicutes and Bacteroidetes were mainly found in biofilms. UniFrac P values confirmed a significant difference among different matrices. Significant differences (P rocks which shared a more similar community structure, while at deep taxonomic resolution two distinct bacterial communities between lichens and rocks were found.

  4. In Vitro Activity of Delafloxacin against Contemporary Bacterial Pathogens from the United States and Europe, 2014

    Science.gov (United States)

    Pfaller, M. A.; Sader, H. S.; Rhomberg, P. R.

    2017-01-01

    ABSTRACT The in vitro activities of delafloxacin and comparator antimicrobial agents against 6,485 bacterial isolates collected from medical centers in Europe and the United States in 2014 were tested. Delafloxacin was the most potent agent tested against methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant S. aureus, Streptococcus pneumoniae, viridans group streptococci, and beta-hemolytic streptococci and had activity similar to that of ciprofloxacin and levofloxacin against certain members of the Enterobacteriaceae. Overall, the broadest coverage of the tested pathogens (Gram-positive cocci and Gram-negative bacilli) was observed with meropenem and tigecycline in both Europe and the United States. Delafloxacin was shown to be active against organisms that may be encountered in acute bacterial skin and skin structure infections, respiratory infections, and urinary tract infections. PMID:28167542

  5. Screening of anti-bacterial activity of medicinal plants from Belize (Central America).

    Science.gov (United States)

    Camporese, A; Balick, M J; Arvigo, R; Esposito, R G; Morsellino, N; De Simone, F; Tubaro, A

    2003-07-01

    Twenty-one extracts from seven herbal drugs, Aristolochia trilobata (Aristolochiaceae) leaves and bark, Bursera simaruba (Burseraceae) bark, Guazuma ulmifolia (Sterculiaceae) bark, Hamelia patens (Rubiaceae) leaves and Syngonium podophyllum (Araceae) leaves and bark, used in traditional medicine of Belize (Central America) as deep and superficial wound healers, were evaluated for their anti-bacterial properties. Activity was tested against standard strains of Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923 and Enterococcus faecalis ATCC 29212. Almost all the extracts were able to inhibit the growth of one or more of the bacterial strains, except that of Enterococcus faecalis. For the first time an anti-microbial activity is reported for Aristolochia trilobata as well as for Syngonium podophyllum. The hexane extracts of Aristolochia trilobata leaves and bark were the most active extracts against Staphylococcus aureus (MIC=0.31 and 0.625mg/ml, respectively).

  6. Development and application of the active surveillance of pathogens microarray to monitor bacterial gene flux

    Directory of Open Access Journals (Sweden)

    Hinds Jason

    2008-10-01

    Full Text Available Abstract Background Human and animal health is constantly under threat by emerging pathogens that have recently acquired genetic determinants that enhance their survival, transmissibility and virulence. We describe the construction and development of an Active Surveillance of Pathogens (ASP oligonucleotide microarray, designed to 'actively survey' the genome of a given bacterial pathogen for virulence-associated genes. Results The microarray consists of 4958 reporters from 151 bacterial species and include genes for the identification of individual bacterial species as well as mobile genetic elements (transposons, plasmid and phage, virulence genes and antibiotic resistance genes. The ASP microarray was validated with nineteen bacterial pathogens species, including Francisella tularensis, Clostridium difficile, Staphylococcus aureus, Enterococcus faecium and Stenotrophomonas maltophilia. The ASP microarray identified these bacteria, and provided information on potential antibiotic resistance (eg sufamethoxazole resistance and sulfonamide resistance and virulence determinants including genes likely to be acquired by horizontal gene transfer (e.g. an alpha-haemolysin. Conclusion The ASP microarray has potential in the clinic as a diagnostic tool, as a research tool for both known and emerging pathogens, and as an early warning system for pathogenic bacteria that have been recently modified either naturally or deliberately.

  7. Isolation of a lead tolerant novel bacterial species, Achromobacter sp. TL-3: assessment of bioflocculant activity.

    Science.gov (United States)

    Batta, Neha; Subudhi, Sanjukta; Lal, Banwari; Devi, Arundhuti

    2013-11-01

    Lead is one of the four heavy metals that has a profound damaging effects on human health. In the recent past there has been an increasing global concern for development of sustainable bioremediation technologies for detoxification of lead contaminant. Present investigation highlights for lead biosorption by a newly isolated novel bacterial species; Achromobacter sp. TL-3 strain, isolated from activated sludge samples contaminated with heavy metals (collected from oil refinery, Assam, North-East India). For isolation of lead tolerant bacteria, sludge samples were enriched into Luria Broth medium supplemented separately with a range of lead nitrate; 250, 500, 750, 1000, 1250 and 1500 ppm respectively. The bacterial consortium that could tolerate 1500 ppm of lead nitrate was selected further for purification of lead tolerant bacterial isolates. Purified lead tolerant bacterial isolates were then eventually inoculated into production medium supplemented with ethanol and glycerol as carbon and energy source to investigate for bioflocculant production. Bioflocculant production was estimated by monitoring the potential of lead tolerant bacterial isolate to flocculate Kaolin clay in presence of 1% CaCl2. Compared to other isolates, TL-3 isolate demonstrated for maximum bioflocculant activity of 95% and thus was identified based on 16S rRNA gene sequence analysis. TL3 isolate revealed maximum homology (98%) with Achromobacter sp. and thus designated as Achromobacter sp. TL-3. Bioflocculant activity of TL-3 isolate was correlated with the change in pH and growth. Achromobacter sp. TL-3 has significant potential for lead biosorption and can be effectively employed for detoxification of lead contaminated waste effluents/waste waters.

  8. Consumer involvement in research projects: the activities of research funders.

    Science.gov (United States)

    O'Donnell, Máire; Entwistle, Vikki

    2004-08-01

    This paper reports findings from a postal questionnaire survey and in-depth interviews with UK funders of health-related research that explored whether, why and how they promote consumer involvement in research projects. Many UK funders of health-related research are adopting a policy of promoting consumer involvement in research projects. Telephone interviews revealed they have several reasons for doing so, and that they vary in the ways they encourage and support researchers to involve consumers. For some, descriptions of consumer involvement in a research proposal are important for project funding decisions. They recognized a need for flexibility when assessing consumer involvement in different contexts. We suggest that funders should continue to work to clarify what they consider to be the parameters of acceptability in terms of consumer involvement and ensure that 'flexible' criteria are fairly applied. Researchers should be aware of particular funders' views when applying for project funding.

  9. Antibacterial activity of halophilic bacterial bionts from marine invertebrates of Mandapam-India

    Directory of Open Access Journals (Sweden)

    Sheryanne Velho-Pereira

    2012-01-01

    Full Text Available Marine ecosystem and its organisms, particularly the invertebrates are recent targets of bioprospecting and mining for a large group of structurally unique natural products encompassing a wide variety of chemical classes such as terpenes, polyketides, acetogenins, peptides and alkaloids of varying structures, having pronounced pharmacological activities. In view of the limited reports on the antibacterials produced by bacteria, isolated from marine sponges, corals and bivalves of Indian origin, the present study is aimed at investigating the antagonistic activities of 100 heterotrophic, halophilic bacterial bionts isolated from 9 sponges, 5 corals and one bivalve. Culture broths of 46 of these bionts were active against human pathogenic bacteria namely Staphylococcus citreus, Proteus vulgaris, Serratio marcesans, Salmonella typhi, Aerobacter aerogenes and Escherichia coli. Further, the ethyl acetate extracts of cell free supernatant confirmed the presence of extracellular bioactive factor, by agar cup diffusion method. Interestingly, highest number of bionts having activity was isolated from corals followed by sponges and bivalve. The study clearly demonstrates that bacterial bionts of marine invertebrates are a rich source of bioactive secondary metabolites against human bacterial pathogens.

  10. DNA-based stable isotope probing enables the identification of active bacterial endophytes in potatoes.

    Science.gov (United States)

    Rasche, Frank; Lueders, Tillmann; Schloter, Michael; Schaefer, Sabine; Buegger, Franz; Gattinger, Andreas; Hood-Nowotny, Rebecca C; Sessitsch, Angela

    2009-03-01

    A (13)CO2 (99 atom-%, 350 ppm) incubation experiment was performed to identify active bacterial endophytes in two cultivars of Solanum tuberosum, cultivars Desirée and Merkur. We showed that after the assimilation and photosynthetic transformation of (13)CO2 into (13)C-labeled metabolites by the plant, the most directly active, cultivar specific heterotrophic endophytic bacteria that consume these labeled metabolite scan be identified by DNA stable isotope probing (DNA-SIP).Density-resolved DNA fractions obtained from SIP were subjected to 16S rRNA gene-based community analysis using terminal restriction fragment length polymorphism analysis and sequencing of generated gene libraries.Community profiling revealed community compositions that were dominated by plant chloroplast and mitochondrial 16S rRNA genes for the 'light' fractions of (13)CO2-incubated potato cultivars and of potato cultivars not incubated with (13)CO2. In the 'heavy' fractions of the (13)CO2-incubated endophyte DNA, a bacterial 492-bp terminal restriction fragment became abundant, which could be clearly identified as Acinetobacter and Acidovorax spp. in cultivars Merkur and Desirée,respectively, indicating cultivar-dependent distinctions in (13)C-label flow. These two species represent two common potato endophytes with known plant-beneficial activities.The approach demonstrated the successful detection of active bacterial endophytes in potato. DNA-SIP therefore offers new opportunities for exploring the complex nature of plant-microbe interactions and plant-dependent microbial metabolisms within the endosphere.

  11. The soluble mannose receptor is released from the liver in cirrhotic patients, but is not associated with bacterial translocation

    DEFF Research Database (Denmark)

    Laursen, Tea L; Rødgaard-Hansen, Sidsel; Møller, Holger J

    2016-01-01

    BACKGROUND & AIMS: Intestinal bacterial translocation is involved in activation of liver macrophages in cirrhotic patients. Macrophages play a key role in liver inflammation and are involved in the pathogenesis of cirrhosis and complications. Bacterial translocation may be determined by presence ...

  12. Structural and functional studies of multiheme cytochromes C involved in extracellular electron transport in bacterial dissimilatory metal reduction.

    Science.gov (United States)

    Tikhonova, T V; Popov, V O

    2014-12-01

    Bacteria utilizing insoluble mineral forms of metal oxides as electron acceptors in respiratory processes are widespread in the nature. The electron transfer from a pool of reduced quinones in the cytoplasmic membrane across the periplasm to the bacterial outer membrane and then to an extracellular acceptor is a key step in bacterial dissimilatory metal reduction. Multiheme cytochromes c play a crucial role in the extracellular electron transfer. The bacterium Shewanella oneidensis MR-1 was used as a model organism to study the mechanism of extracellular electron transport. In this review, we discuss recent data on the composition, structures, and functions of multiheme cytochromes c and their functional complexes responsible for extracellular electron transport in Shewanella oneidensis.

  13. Comparative biocidal activity of peracetic acid, benzalkonium chloride and ortho-phthalaldehyde on 77 bacterial strains.

    Science.gov (United States)

    Bridier, A; Briandet, R; Thomas, V; Dubois-Brissonnet, F

    2011-07-01

    Despite numerous reports on biocide activities, it is often difficult to have a reliable and relevant overview of bacterial resistance to disinfectants because each work challenges a limited number of strains and tested methods are often different. The aim of this study was to evaluate the bactericidal activity of three different disinfectants commonly used in industrial or medical environments (peracetic acid, benzalkonium chloride and ortho-phthalaldehyde) against 77 bacterial strains from different origins using one standard test method (NF EN 1040). Results highlight the existence of high interspecific variability of resistance to disinfectants and, contrary to widespread belief, Gram-positive strains generally appeared more resistant than Gram-negative strains. Resistance was also variable among strains of the same species such as Bacillus subtilis to peracetic acid, Pseudomonas aeruginosa to benzalkonium chloride and Staphylococcus aureus to ortho-phthalaldehyde.

  14. Controlled release and antibacterial activity of tetracycline hydrochloride-loaded bacterial cellulose composite membranes.

    Science.gov (United States)

    Shao, Wei; Liu, Hui; Wang, Shuxia; Wu, Jimin; Huang, Min; Min, Huihua; Liu, Xiufeng

    2016-07-10

    Bacterial cellulose (BC) is widely used in biomedical applications. In this study, we prepared an antibiotic drug tetracycline hydrochloride (TCH)-loaded bacterial cellulose (BC) composite membranes, and evaluated the drug release, antibacterial activity and biocompatibility. The structure and morphology of the fabricated BC-TCH composite membranes were characterized using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The TCH release results show that the incorporation of BC matrix to load TCH is able to control the release. In vitro antibacterial assay demonstrate that the developed BC-TCH composites displayed excellent antibacterial activity solely associated with the loaded TCH drug. More importantly, the BC-TCH composite membranes display good biocompatibility. These characteristics of BC-TCH composite membranes indicate that they may successfully serve as wound dressings and other medical biomaterials.

  15. Inactivation of bacterial biofilms using visible-light-activated unmodified ZnO nanorods

    Science.gov (United States)

    Aponiene, Kristina; Serevičius, Tomas; Luksiene, Zivile; Juršėnas, Saulius

    2017-09-01

    Various zinc oxide (ZnO) nanostructures are widely used for photocatalytic antibacterial applications. Since ZnO possesses a wide bandgap, it is believed that only UV light may efficiently assist bacterial inactivation, and diverse crystal lattice modifications should be applied in order to narrow the bandgap for efficient visible-light absorption. In this work we show that even unmodified ZnO nanorods grown by an aqueous chemical growth technique are found to possess intrinsic defects that can be activated by visible light (λ = 405 nm) and successfully applied for total inactivation of various highly resistant bacterial biofilms rather than more sensitive planktonic bacteria. Time-resolved fluorescence analysis has revealed that visible-light excitation creates long-lived charge carriers (τ > 1 μs), which might be crucial for destructive biochemical reactions achieving significant bacterial biofilm inactivation. ZnO nanorods covered with bacterial biofilms of Enterococcus faecalis MSCL 302 after illumination by visible light (λ = 405 nm) were inactivated by 2 log, and Listeria monocytogenes ATCL3C 7644 and Escherichia coli O157:H7 biofilms by 4 log. Heterogenic waste-water microbial biofilms, consisting of a mixed population of mesophilic bacteria after illumination with visible light were also completely destroyed.

  16. Immobilization of cells with nitrilase activity from a thermophilic bacterial strain.

    Science.gov (United States)

    Kabaivanova, L; Dobreva, E; Dimitrov, P; Emanuilova, E

    2005-01-01

    Cells of the moderately thermophilic Bacillus sp. UG-5B strain, producing nitrilase (EC3.5.5.1), which converts nitriles directly to the corresponding acid and ammonia, were immobilized using different types of matrices and techniques. A variety of sol-gel silica hybrids were tested for entrapment and adsorption of bacterial cells as well as chemical binding on polysulphone membranes. Activation of the matrix surface with formaldehyde led to an increase in immobilization efficiency and operational stability of the biocatalysts. Among the supports screened, membranes gave the best results for enzyme activity and especially operational stability, with retention of 100% activity after eight reaction cycles.

  17. A novel ion-beam-mutation effect application in identification of gene involved in bacterial antagonism to fungal infection of ornamental crops

    Energy Technology Data Exchange (ETDEWEB)

    Mahadtanapuk, S. [Faculty of Agriculture and Natural Resources, University of Phayao, Maeka, Muang, Phayao 56000 (Thailand); Teraarusiri, W. [Central Laboratory, University of Phayao, Maeka, Muang, Phayao 56000 (Thailand); Nanakorn, W. [The Crown Property Bureau, 173 Nakhonratchasrima Road, Dusit, Bangkok 10300 (Thailand); Yu, L.D., E-mail: yuld@thep-center.org [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Thongkumkoon, P. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Anuntalabhochai, S., E-mail: soanu.1@gmail.com [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

    2014-05-01

    Highlights: • Ion beam bombardment induced mutation in bacterial B. licheniformis. • A mutant lost antifungal activity. • DNA fingerprint of the mutant was analyzed. • The lost gene was indentified to code for TrxR gene. • TrxR gene from B. licheniformis expressed the flower antagonism to fungi. - Abstract: This work is on a novel application of ion beam effect on biological mutation. Bacillus licheniformis (B. licheniformis) is a common soil bacterium with an antagonistic effect on Curcuma alismatifolia Gagnep. and Chrysanthemum indicum Linn. In an attempt to control fungal diseases of local crops by utilizing B. licheniformis, we carried out gene analysis of the bacterium to understand the bacterial antagonistic mechanism. The bacterial cells were bombarded to induce mutations using nitrogen ion beam. After ion bombardment, DNA analysis revealed that the modified polymorphism fragment present in the wild type was missing in a bacterial mutant which lost the antifungal activity. The fragments conserved in the wild type but lost in the mutant bacteria was identified to code for the thioredoxin reductase (TrxR) gene. The gene analysis showed that the TrxR gene from B. licheniformis had the expression of the antagonism to fungi in a synchronous time evolution with the fungus inhibition when the bacteria were co-cultivated with the fungi. The collective results indicate the TrxR gene responsible for the antagonism of bacteria B. licheniformis to fungal infection.

  18. Involvement of bacterial TonB-dependent signaling in the generation of an oligogalacturonide damage-associated molecular pattern from plant cell walls exposed to Xanthomonas campestris pv. campestris pectate lyases.

    Science.gov (United States)

    Vorhölter, Frank-Jörg; Wiggerich, Heinrich-Günter; Scheidle, Heiko; Sidhu, Vishaldeep Kaur; Mrozek, Kalina; Küster, Helge; Pühler, Alfred; Niehaus, Karsten

    2012-10-19

    Efficient perception of attacking pathogens is essential for plants. Plant defense is evoked by molecules termed elicitors. Endogenous elicitors or damage-associated molecular patterns (DAMPs) originate from plant materials upon injury or pathogen activity. While there are comparably well-characterized examples for DAMPs, often oligogalacturonides (OGAs), generated by the activity of fungal pathogens, endogenous elicitors evoked by bacterial pathogens have been rarely described. In particular, the signal perception and transduction processes involved in DAMP generation are poorly characterized. A mutant strain of the phytopathogenic bacterium Xanthomonas campestris pv. campestris deficient in exbD2, which encodes a component of its unusual elaborate TonB system, had impaired pectate lyase activity and caused no visible symptoms for defense on the non-host plant pepper (Capsicum annuum). A co-incubation of X. campestris pv. campestris with isolated cell wall material from C. annuum led to the release of compounds which induced an oxidative burst in cell suspension cultures of the non-host plant. Lipopolysaccharides and proteins were ruled out as elicitors by polymyxin B and heat treatment, respectively. After hydrolysis with trifluoroacetic acid and subsequent HPAE chromatography, the elicitor preparation contained galacturonic acid, the monosaccharide constituent of pectate. OGAs were isolated from this crude elicitor preparation by HPAEC and tested for their biological activity. While small OGAs were unable to induce an oxidative burst, the elicitor activity in cell suspension cultures of the non-host plants tobacco and pepper increased with the degree of polymerization (DP). Maximal elicitor activity was observed for DPs exceeding 8. In contrast to the X. campestris pv. campestris wild type B100, the exbD2 mutant was unable to generate elicitor activity from plant cell wall material or from pectin. To our knowledge, this is the second report on a DAMP generated

  19. Involvement of bacterial TonB-dependent signaling in the generation of an oligogalacturonide damage-associated molecular pattern from plant cell walls exposed to Xanthomonas campestris pv. campestris pectate lyases

    Directory of Open Access Journals (Sweden)

    Vorhölter Frank-Jörg

    2012-10-01

    Full Text Available Abstract Background Efficient perception of attacking pathogens is essential for plants. Plant defense is evoked by molecules termed elicitors. Endogenous elicitors or damage-associated molecular patterns (DAMPs originate from plant materials upon injury or pathogen activity. While there are comparably well-characterized examples for DAMPs, often oligogalacturonides (OGAs, generated by the activity of fungal pathogens, endogenous elicitors evoked by bacterial pathogens have been rarely described. In particular, the signal perception and transduction processes involved in DAMP generation are poorly characterized. Results A mutant strain of the phytopathogenic bacterium Xanthomonas campestris pv. campestris deficient in exbD2, which encodes a component of its unusual elaborate TonB system, had impaired pectate lyase activity and caused no visible symptoms for defense on the non-host plant pepper (Capsicum annuum. A co-incubation of X. campestris pv. campestris with isolated cell wall material from C. annuum led to the release of compounds which induced an oxidative burst in cell suspension cultures of the non-host plant. Lipopolysaccharides and proteins were ruled out as elicitors by polymyxin B and heat treatment, respectively. After hydrolysis with trifluoroacetic acid and subsequent HPAE chromatography, the elicitor preparation contained galacturonic acid, the monosaccharide constituent of pectate. OGAs were isolated from this crude elicitor preparation by HPAEC and tested for their biological activity. While small OGAs were unable to induce an oxidative burst, the elicitor activity in cell suspension cultures of the non-host plants tobacco and pepper increased with the degree of polymerization (DP. Maximal elicitor activity was observed for DPs exceeding 8. In contrast to the X. campestris pv. campestris wild type B100, the exbD2 mutant was unable to generate elicitor activity from plant cell wall material or from pectin. Conclusions To our

  20. Soil factors involved in the diversity and structure of soil bacterial communities in commercial organic olive orchards in Southern Spain.

    Science.gov (United States)

    Landa, B B; Montes-Borrego, M; Aranda, S; Soriano, M A; Gómez, J A; Navas-Cortés, J A

    2014-04-01

    Nowadays, there is a tendency in olive production systems to reduce tillage or keep a vegetative cover to reduce soil erosion and degradation. However, there is scarce information on the effects of different soil management systems (SMS) in soil bacterial community composition of olive groves. In this study, we have evaluated the effects of soil type and different SMS implemented to control weeds in the structure and diversity of bacterial communities of 58 soils in the two geographic areas that best represent the organic olive production systems in Spain. Bacterial community composition assessed by frequency and intensity of occurrence of terminal restriction profiles (TRFs) derived from terminal restriction fragment length polymorphism (T-RFLP) analysis of amplified 16S ribosomal deoxyribonucleic acid were strongly correlated with soil type/field site (Eutric/Calcaric) that differed mainly in soil particle size distribution and soil pH, followed by a strong effect of SMS, in that order. Canonical discriminant (CD) analysis of TRFs properly classified all of the olive orchard soils as belonging to their respective soil type or SMS. Furthermore, only a small set of TRFs were enough to clearly and significantly differentiate soil samples according to soil type or SMS. Those specific TRFs could be used as bioindicators to assess the effect of changes in SMS aimed to enhance soil quality in olive production systems.

  1. Activity of Norspermidine on Bacterial Biofilms of Multidrug-Resistant Clinical Isolates Associated with Persistent Extremity Wound Infections.

    Science.gov (United States)

    Cardile, Anthony P; Woodbury, Ronald L; Sanchez, Carlos J; Becerra, Sandra C; Garcia, Rebecca A; Mende, Katrin; Wenke, Joseph C; Akers, Kevin S

    2016-11-19

    Biofilm formation is a major virulence factor for numerous pathogenic bacteria and is cited as a central event in the pathogenesis of chronic human infections, which is in large part due to excessive extracellular matrix secretion and metabolic changes that occur within the biofilm rendering them highly tolerant to antimicrobial treatments. Polyamines, including norspermidine, play central roles in bacterial biofilm development, but have also recently been shown to inhibit biofilm formation in select strains of various pathogenic bacteria. The aim of this study was to evaluate in vitro the biofilm dispersive and inhibitory activities of norspermidine against multidrug-resistant clinical isolates of Acinetobacter baumannii(n = 4), Klebsiella pneumoniae (n = 3), Pseudomonas aeruginosa (n = 5) and Staphylococcus aureus (n = 4) associated with chronic extremity wound infections using the semi-quantitative 96-well plate method and confocal laser microscopy. In addition to the antibiofilm activity, biocompatibility of norspermidine was also evaluated by measuring toxicity in vitro to human cell lines and whole porcine tissue explants using MTT viability assay and histological analysis. Norspermidine (5-20 mM) had variable dispersive and inhibitory activity on biofilms which was dependent on both the strain and species. Of the clinical bacterial species evaluated herein, A. baumannii isolates were the most sensitive to the effect of norspermidine, which was in part due to the inhibitory effects of norspermidine on bacterial motility and expression of genes involved in the production of homoserine lactones and quorum sensing molecules both essential for biofilm formation. Importantly, exposure of cell lines and whole tissues to norspermidine for prolonged periods of time (≥24 h) was observed to reduce viability and alter tissue histology in a time and concentration dependent manner, with 20 mM exposure having the greatest negative effects on both

  2. FUNCTIONAL AND METABOLIC ACTIVITY OF NEUTROPHILIC GRANULOCYTES IN CASE OF ACUTE BACTERIAL RHINOSINUSITIS

    Directory of Open Access Journals (Sweden)

    O. A. Kolenchukova

    2013-01-01

    Full Text Available Abstract. The functional and metabolic activities of neutrophilic granulocytes in patients with acute bacterial rhinosinusitis (ABRS have been studied. Characteristics of the indices of chemiluminescence and bioluminescence for neutrophils, extracted from venous blood and maxillary sinus were compared. It was demonstrated the decrease of intensity of APK production in neutrophils, extracted from inflammation point, with simultaneous decrease of intensity of plastic processes and increasing of energy processes in compare with the same indices in blood cells.

  3. Microbial activity of soil with sulfentrazone associated with phytoremediator species and inoculation with a bacterial consortium

    Directory of Open Access Journals (Sweden)

    Christiane Augusta Diniz Melo

    Full Text Available ABSTRACT Phytostimulation plays a key role in the process of rhizodegradation of herbicides in soil. Additionally, bio-enhancement associated with phytoremediation may increase the efficiency of the decontamination process of soils with herbicides. Therefore, the objective of this study was to evaluate the biomass and microbial activity of soil contaminated with sulfentrazone and cultivated with phytoremediator species plus a bacterial consortium. The experiment was conducted in a greenhouse, carried out with a 2 × 4 × 4 completely randomized factorial design with 4 replications. The first factor consisted of the presence or absence of bio-enhancement with a bacterial consortium composed of Pseudomonas bacteria; the second factor consisted of a monoculture or mixed cultivation of 2 phytoremediator species Canavalia ensiformis and Helianthus annuus, besides the absence of cultivation; the third factor was made up by the bio-remediation time (25, 45, 65, and 85 days after thinning. Uncultivated soils displayed low values of microbial biomass carbon and microbial quotient as well as high values of metabolic quotient throughout the bio-remediation time, indicating the importance of cultivating phytoremediator species for the stimulation of soil microbiota. Bio-enhancement with the bacterial consortium, in general, promoted an increase in the microbial biomass and activity of soil contaminated with sulfentrazone. In the presence of the bacterial consortium, Canavalia ensiformis stimulated a greater activity of associated microbiota and supported a higher microbial biomass. Phytoremediation associated with microbial bio-enhancement are thus promising techniques for the bio-remediation for soils contaminated with sulfentrazone. This technique enhances the biomass and activity of soil microorganisms.

  4. In vitro anti- bacterial activity of leaves extracts of Albizia lebbeck Benth against some selected pathogens

    Institute of Scientific and Technical Information of China (English)

    Mohammed Nazneen Bobby; Edward Gnanaraj Wesely; MarimuthuAntonisamy Johnson

    2012-01-01

    Objective: To screen the anti-bacterial activity of Albizia lebbeck (A. lebbeck) Benth leaves extract against the selected bacterial pathogens viz., Bacillus subtilis (MTCC441), Escherichia coli (MTCC443), Klebsiella pneumonia (MTCC 109), Proteus vulgaris (MTCC742), Pseudomonas aeruginosa (MTCC741), Salmonella typhii (MTCC733) and Staphylococus aureus (MTCC96).Methods:The leaves extracts of A. lebbeck was tested against bacteria by the agar disc diffusion method. Results: Results of the present study indicated that different extracts of A. lebbeck showed inhibitory effects against the pathogens. The present study results demonstrated that methanolic extracts of A. lebbeck conferred the widest spectrum activities that inhibited the growth of all studied pathogens with the maximum zone of inhibition. The methanolic extracts ofA. lebbeck illustrated the highest zone of inhibition against the pathogens Bacillus subtilis (16 mm), Escherichia coli (22 mm), Klebsiella pneumonia (11 mm), Proteus vulgaris (18 mm), Pseudomonas aeruginosa (22 mm), Salmonella typhii (23 mm) and Staphylococus aureus (17 mm). The ethyl acetate extracts demonstrated maximum zone of inhibition against Escherichia coli (26 mm), Pseudomonas aeruginosa (22 mm) and Klebsiella pneumonia (16 mm). Conclusions: It is expected that this study would direct to the establishment of some active compounds that could be used to formulate new and more potent anti-bacterial drugs of natural origin.

  5. Screening of Bacterial Strains for Polygalacturonase Activity: Its Production by Bacillus sphaericus (MTCC 7542

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    Ranveer Singh Jayani

    2010-01-01

    Full Text Available At present almost all the pectinolytic enzymes used for industrial applications are produced by fungi. There are a few reports of pectinase production by bacterial strains. Therefore, in the present study, seventy-four bacterial strains, isolated from soil and rotten vegetable samples, were screened for polygalacturonase production. The strain PG-31, which gave maximum activity, was identified as Bacillus sphaericus (MTCC 7542. Maximal quantities of polygalacturonase were produced when a 16-hours-old inoculum was used at 7.5% (v/v in production medium and incubated in shaking conditions (160 rpm for 72 hours. The optimal temperature and pH for bacterial growth and polygalacturonase production were found to be 30∘C and 6.8, respectively. Maximum enzyme production resulted when citrus pectin was used as the carbon source at a concentration of 1.25% (w/v, whereas other carbon sources led to a decrease (30%–70% in enzyme production. Casein hydrolysate and yeast extract used together as organic nitrogen source gave best results, and ammonium chloride was found to be the most suitable inorganic nitrogen source. The supplementation of media with 0.9% (w/v D-galacturonic acid led to a 23% increase in activity. Bacillus sphaericus, a bacterium isolated from soil, produced good amount of polygalacturonase activity at neutral pH; hence, it would be potentially useful to increase the yield of banana, grape, or apple juice.

  6. Anti-enteric bacterial activity of the traditional medicinal plants of Kanyakumari coast, Tamilnadu, India

    Institute of Scientific and Technical Information of China (English)

    Suyambu Rajan; Parameshwaran Suvetha; Thiyagarajan Thirunalasundari; Solomon Jeeva

    2015-01-01

    Objective: To evaluate the antimicrobial potentials of 6 traditionally used medicinal plants to treat gastrointestinal infection against pathogenic bacteria, as most of the pathogens develop drug resistance against commonly used antibiotics. Methods: Crude extracts from different parts of different plants were tested against bacterial strains of clinical significance. Extraction of bioactive principles was done with water and ethanol. Evaluation of antibacterial activity was done by disc diffusion assay against selected bacterial stains. Results: Of the 6 different plant materials tested, extracts prepared from Psidium guajava leaves showed significantly higher efficacy. Extracts prepared using alcohol exhibited higher antibacterial activity when compared to their corresponding aqueous extracts. Conclusions: The findings of the present study suggested that phytochemical extracts of the presently studied plant materials possess significant anti-enteric bacterial activity, and thus lend pharmacological credibility to the suggested traditional use of the plant as a natural remedy for the treatment, management and/or control of gastrointestinal diseases in the coastal tracts of Kanyakumari district, Tamilnadu, India.

  7. Anti-enteric bacterial activity of the traditional medicinal plants of Kanyakumari coast, Tamilnadu, India

    Directory of Open Access Journals (Sweden)

    Suyambu Rajan

    2015-08-01

    Full Text Available Objective: To evaluate the antimicrobial potentials of 6 traditionally used medicinal plants to treat gastrointestinal infection against pathogenic bacteria, as most of the pathogens develop drug resistance against commonly used antibiotics. Methods: Crude extracts from different parts of different plants were tested against bacterial strains of clinical significance. Extraction of bioactive principles was done with water and ethanol. Evaluation of antibacterial activity was done by disc diffusion assay against selected bacterial stains. Results: Of the 6 different plant materials tested, extracts prepared from Psidium guajava leaves showed significantly higher efficacy. Extracts prepared using alcohol exhibited higher antibacterial activity when compared to their corresponding aqueous extracts. Conclusions: The findings of the present study suggested that phytochemical extracts of the presently studied plant materials possess significant anti-enteric bacterial activity, and thus lend pharmacological credibility to the suggested traditional use of the plant as a natural remedy for the treatment, management and/or control of gastrointestinal diseases in the coastal tracts of Kanyakumari district, Tamilnadu, India.

  8. Efficacy of coating activated carbon with milk proteins to prevent binding of bacterial cells from foods for PCR detection.

    Science.gov (United States)

    Opet, Nathan J; Levin, Robert E

    2013-08-01

    Foods contaminated with pathogens are common sources of illness. Currently, the most common and sensitive rapid detection method involves the PCR. However, food matrices are complex and contain inhibitors that limit the sensitivity of the PCR. The use of coated activated carbon can effectively facilitate the removal of PCR inhibitors without binding targeted bacterial cells from food samples. With the use of activated carbon coated with milk proteins, a cell recovery at pH 7.0 of 95.7%±2.0% was obtained, compared to control uncoated activated carbon, which yielded a cell recovery of only 1.1%±0.8%. In addition, the milk protein coated activated carbon was able to absorb similar amounts of soluble compounds as uncoated activated carbon, with the exception of bovine hemoglobin. This suggests that the use of milk proteins to coat activated carbon may therefore serve as a suitable replacement for bentonite in the coating of activated carbon, which has previously been used for the removal of PCR inhibitors from food.

  9. The Relation Between Ocular/Nasal Bacterial Distribution, Staphylococcus aureus Colonization and Ocular and Nasal Involvement in Atopic Dermatitis Patients - Original Article

    Directory of Open Access Journals (Sweden)

    Berna Şanlı Erdoğan

    2008-12-01

    Full Text Available Objective: It was aimed to determine bacteria distribution and S.aureus colonization in nares, fornix and eyelid margin of patients with atopic dermatitis (AD compared to controls and to investigate it’s relationship with skin and eye involvement. Methods: Patients dermatological and opthalmologic examinations were done. The standart tear break-up time and Schirmer tests were performed. Samples were taken from fornix, eyelid margin and nares for bacterial culture. Results: Tweenty seven patients and 28 controls were included. There was no difference between the patients with and without eye involvement with respect to dry eye (p>0.05. The bacteria was more frequently isolated in patients (85.2% than controls (60.7%, however S.aureus colonization (51.9%, 50.0% respectively didn’t differ in both groups (p=0.042, p>0.05. The disease severity was positively correlated with S.aureus colonization (p=0.031. There was no difference between the patients with and without eye involvement with respect to S.aureus colonization and presence of bacteria (p>0.05. No bacteria was isolated from patients whom tear function analyses were performed. Conclusions: It wasn’t established an increased percent of S.aureus colonization in AD patients compared with controls. There was no association between dry eye and eye involvement. No comment could be remarked about the possible relation between dry eye and bacterial colonization.

  10. Ion Channels Activated by Mechanical Forces in Bacterial and Eukaryotic Cells.

    Science.gov (United States)

    Sokabe, Masahiro; Sawada, Yasuyuki; Kobayashi, Takeshi

    2015-01-01

    Since the first discovery of mechanosensitive ion channel (MSC) in non-sensory cells in 1984, a variety of MSCs has been identified both in prokaryotic and eukaryotic cells. One of the central issues concerning MSCs is to understand the molecular and biophysical mechanisms of how mechanical forces activate/open MSCs. It has been well established that prokaryotic (mostly bacterial) MSCs are activated exclusively by membrane tension. Thus the problem to be solved with prokaryotic MSCs is the mechanisms how the MSC proteins receive tensile forces from the lipid bilayer and utilize them for channel opening. On the other hand, the activation of many eukaryotic MSCs crucially depends on tension in the actin cytoskeleton. By using the actin cytoskeleton as a force sensing antenna, eukaryotic MSCs have obtained sophisticated functions such as remote force sensing and force-direction sensing, which bacterial MSCs do not have. Actin cytoskeletons also give eukaryotic MSCs an interesting and important function called "active touch sensing", by which cells can sense rigidity of their substrates. The contractile actin cytoskeleton stress fiber (SF) anchors its each end to a focal adhesion (FA) and pulls the substrate to generate substrate-rigidity-dependent stresses in the FA. It has been found that those stresses are sensed by some Ca2+-permeable MSCs existing in the vicinity of FAs, thus the MSCs work as a substrate rigidity sensor that can transduce the rigidity into intracellular Ca2+ levels. This short review, roughly constituting of two parts, deals with molecular and biophysical mechanisms underlying the MSC activation process mostly based on our recent studies; (1) structure-function in bacterial MSCs activation at the atomic level, and (2) roles of actin cytoskeletons in the activation of eukaryotic MSCs.

  11. The Evaluation of Bacterial Contamination of Active Radiography Apparatus in Dental Centers of Hamadan City

    Directory of Open Access Journals (Sweden)

    A. Eskandarloo

    2006-01-01

    Full Text Available Introduction & Objective: During the most dental procedures, contamination of devices with blood, saliva and other body fluids, which is the most important factor for transmission of infectious diseases, is inevitable. Therefore principles of infection control should be carefully considered in the dentistry. The purpose of this study was the evaluation of bacterial contamination of active radiographic apparatus in dental centers of Hamadan city in year 2003. Materials & Methods : In this cross-sectional study 37 radiographic apparatus in dental centers of Hamadan were evaluated. Samples were collected from four area (25 cm2 each that are frequently touched by dentists, personnel, etc. using a swab. The swab was inserted into the carrier media containing thioglycolate, a smear was obtained from the solution and remaining solution was cultured in blood agar. Smear and blood agar cultures were transferred to microbiology lab to determine bacterial contamination level as well as bacterial typing. According to WHO criteria the area which has more than 10 microorganism/cm2 is considered as contaminated. Results: It was found that 13 of radiographic apparatus(35% were contaminated, the most frequent bacterial type detected in this study was micrococcus (75.7% and the least were enterobacter and nocardia (2.7% each. Antiseptic materials used for decontamination of the devices were as follow : Alcohol (43.2% , Deconex (32.4% , Micro10 (18.9% , Savlon (10.8% , Hypochlorid (5.4% , Glutaraldehyde (2.7%. Conclusion: Based on the results (35% bacterial contamination it can be concluded that careful performance of infection control principles, daily decontamination of devices and offering periodic instructions for dental personnel are essential.

  12. NITRIC OXIDE ACTIVITY OF NEUTROPHIL IN BLOOD AND CEREBROSPINAL FLUID OF THE CHILDREN WITH BACTERIAL AND VIRAL MENINGITIS

    Directory of Open Access Journals (Sweden)

    V. P. Molochniy

    2014-01-01

    Full Text Available The article presents the results of study of nitric oxide activity of neutrophil leucocytic and freeradical processes in blood and cerebrospinal fluid of the children with bacterial and viral meningitison the acute period diseases. The peculiarities or activity of freeradical processes and nitric oxide of cerebrospinal fluid with bacterial meningitis in acute period diseases and activities of studies of ferments with the health children. 

  13. Proinflammatory effects of bacterial lipoprotein on human neutrophil activation status, function and cytotoxic potential in vitro.

    LENUS (Irish Health Repository)

    Power, C

    2012-02-03

    Bacterial lipoprotein (BLP) is the most abundant protein in gram-negative bacterial cell walls, heavily outweighing lipopolysaccharide (LPS). Herein we present findings demonstrating the potent in vitro effects of BLP on neutrophil (PMN) activation status, function, and capacity to transmigrate an endothelial monolayer. PMNs are the principal effectors of the initial host response to injury or infection and constitute a significant threat to invading bacterial pathogens. The systemic inflammatory response syndrome (SIRS) is characterised by significant host tissue injury mediated, in part, by uncontrolled regulation of PMN cytotoxic activity. We found that BLP-activated human PMN as evidenced by increased CD11b\\/CD18 (Mac-1) expression. Up-regulation of PMN Mac-1 in response to BLP occurred independently of membrane-bound CD14 (mCD14). A similar up-regulation of intercellular adhesion molecule-1 (ICAM-1) on endothelial cells was observed whilst E-Selectin expression was unaffected. PMN transmigration across a human umbilical vein endothelial cell (HUVEC) monolayer was markedly increased after treating either PMN\\'s or HUVEC independently with BLP. This increased transmigration did not occur as a result of any direct effect of BLP on HUVEC monolayer permeability, assessed objectively using the passage of FITC-labeled Dextran-70. BLP primed PMN for enhanced respiratory burst and superoxide anion production in response to PMA, but did not influence phagocytosis of opsonized Escherichia coli. BLP far exceeds LPS as a gram-negative bacterial wall component, these findings therefore implicate BLP as an additional putative mediator of SIRS arising from gram-negative infection.

  14. Psychometric evaluation of the Sinonasal Outcome Test-16 and activity impairment assessment in acute bacterial sinusitis.

    Science.gov (United States)

    Quadri, Nuz; Lloyd, Andrew; Keating, Karen N; Nafees, Beenish; Piccirillo, Jay; Wild, Diane

    2013-07-01

    To validate the Sinonasal Outcome Test-16 and Activity Impairment Assessment in patients with acute bacterial sinusitis. Data were used from a phase III clinical trial designed to evaluate the efficacy and safety of moxifloxacin 400 mg once daily for 5 consecutive days in the treatment of acute bacterial sinusitis. The psychometric properties and factor structure of the 2 measures were assessed. Participants were given the measures to self-complete using either a telephone voice response system or a paper-and-pencil format. Three hundred seventy-four patients with acute bacterial sinusitis were used in the analysis. Patients received either a placebo or 400 mg moxifloxacin once daily. Patients were then reviewed at test of cure and follow-up. All analyses were conducted on a combined sample of placebo and active treatment patients. The Sinonasal Outcome Test-16 was associated with minimal missing data at baseline but a higher proportion by test of cure. There was no evidence of floor or ceiling effects and no significant skew. The Activity Impairment Assessment also had low missing data at baseline and no obvious floor or ceiling effects, but the data were not normally distributed. Both measures had good internal consistency. Convergent and divergent validity as well as sensitivity and the minimally important difference are also reported. The measures both have good psychometric properties and are suitable for use with patients with acute bacterial sinusitis. Both instruments are sensitive. The minimal important difference estimates for the Sinonasal Outcome Test-16 are quite high but are similar to estimates reported previously.

  15. Antimicrobial properties of arginine- and lysine-rich histones and involvement of bacterial outer membrane protease T in their differential mode of actions.

    Science.gov (United States)

    Tagai, Chihiro; Morita, Shuu; Shiraishi, Takayuki; Miyaji, Kazuyuki; Iwamuro, Shawichi

    2011-10-01

    There is growing evidence of the antimicrobial properties of histones and histone-derived peptides; however, most of them are specific to lysine (Lys)-rich histones (H1, H2A, and H2B). In the present study, we focused on arginine (Arg)-rich histones (H3 and H4) and investigated their antimicrobial properties in comparison with those of histone H2B. In a standard microdilution assay, calf thymus histones H2B, H3, and H4 showed growth inhibitory activity against the bacterial outer membrane protease T (OmpT) gene-expressing Escherichia coli strain JCM5491 with calculated 50% growth inhibitory concentrations of 3.8, 10, and 12.7 μM, respectively. A lysate prepared from the JCM5491 cells was capable of strongly, moderately, and slightly fragmenting histones H2B, H3, and H4, respectively. While the lysate prepared from the cells of the ompT-deleted E. coli strain BL21(DE3) did not digest these histones, the ompT-transformed BL21(DE3), termed BL21/OmpT(+), cell lysate digested the histones more strongly than the JCM5491 cell lysate. Laser confocal and scanning electron microscopic analyses demonstrated that while histone H2B penetrated the cell membrane of JCM5491 or BL21/OmpT(+) cells, histones H3 and H4 remained on the cell surface and subsequently disrupted the cell membrane structure with bleb formation in a manner similar to general antimicrobial peptides. The BL21(DE3) cells treated with each histone showed no bleb formation, but cell integrity was affected and the cell surface was corrugated. Consequently, it is suggested that OmpT is involved in the antimicrobial properties of Arg- and Lys-rich histones and that the modes of antimicrobial action of these histones are different. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. Multiplex cytokine analyses in dogs with pyometra suggest involvement of KC-like chemokine in canine bacterial sepsis.

    Science.gov (United States)

    Karlsson, Iulia; Hagman, Ragnvi; Johannisson, Anders; Wang, Liya; Södersten, Fredrik; Wernersson, Sara

    2016-02-01

    Clinical diagnostic criteria for sepsis (systemic inflammatory response syndrome caused by infection) are unspecific and, therefore, biomarkers for sepsis diagnosis are needed for appropriate treatment and patient survival. Pyometra, a common disease caused by bacterial infection of the uterus, results in sepsis in nearly 60% of cases in dogs. We used dogs with pyometra as a natural model for sepsis and collected serum samples from 39 dogs, of which 22 with pyometra and 17 healthy controls. Dogs with pyometra were further grouped into dogs with sepsis (n=18) and without sepsis (n=4). Serum concentrations of a panel of cytokines, including keratinocyte-derived chemokine (KC)-like, granulocyte-macrophages colony stimulating factor (GM-CSF), interleukin (IL)-2, IL-4, IL-6, IL-7, IL-8, IL-10, IL-15, IL-18, chemokine C-X-C motif ligand (CXCL)10 and tumor necrosis factor (TNF)-α, were measured using multiplex analyses. Serum C-reactive protein (CRP) levels were determined using an automated immunoturbidimetric assay. In addition to physical examination hematological and serum biochemical analyses were performed to evaluate the overall status of the dogs. Significantly higher concentrations of KC-like (757 vs 304 pg/ml) were detected in dogs with pyometra as compared to healthy dogs. Within the pyometra group, dogs with sepsis compared to dogs without sepsis had a higher KC-like concentration (873 vs 300 pg/ml). Hemoglobin levels were significantly lower in dogs with pyometra compared to healthy dogs, regardless of the presence or absence of sepsis, and correlated negatively with KC-like. KC-like concentrations correlated positively with CRP, number of hospitalization days, number of monocytes, concentrations of IL-8, and percentage band neutrophils. Our data suggest that bacterial infection triggers the expression of KC-like and further studies are warranted of KC-like as a possible biomarker for diagnosing sepsis and uterine bacterial infection in dogs. Copyright

  17. Predicting the pathway involved in post-translational modification of Elongation factor P in a subset of bacterial species

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    de Crécy-Lagard Valérie

    2010-01-01

    Full Text Available Abstract Background The bacterial elongation factor P (EF-P is strictly conserved in bacteria and essential for protein synthesis. It is homologous to the eukaryotic translation initiation factor 5A (eIF5A. A highly conserved eIF5A lysine is modified into an unusual amino acid derived from spermidine, hypusine. Hypusine is absolutely required for eIF5A's role in translation in Saccharomyces cerevisiae. The homologous lysine of EF-P is also modified to a spermidine derivative in Escherichia coli. However, the biosynthesis pathway of this modification in the bacterial EF-P is yet to be elucidated. Presentation of the Hypothesis Here we propose a potential mechanism for the post-translational modification of EF-P. By using comparative genomic methods based on physical clustering and phylogenetic pattern analysis, we identified two protein families of unknown function, encoded by yjeA and yjeK genes in E. coli, as candidates for this missing pathway. Based on the analysis of the structural and biochemical properties of both protein families, we propose two potential mechanisms for the modification of EF-P. Testing the hypothesis This hypothesis could be tested genetically by constructing a bacterial strain with a tagged efp gene. The tag would allow the purification of EF-P by affinity chromatography and the analysis of the purified protein by mass spectrometry. yjeA or yjeK could then be deleted in the efp tagged strain and the EF-P protein purified from each mutant analyzed by mass spectrometry for the presence or the absence of the modification. This hypothesis can also be tested by purifying the different components (YjeK, YjeA and EF-P and reconstituting the pathway in vitro. Implication of the hypothesis The requirement for a fully modified EF-P for protein synthesis in certain bacteria implies the presence of specific post-translational modification mechanism in these organisms. All of the 725 bacterial genomes analyzed, possess an efp gene

  18. Role of the σ54 Activator Interacting Domain in Bacterial Transcription Initiation

    Energy Technology Data Exchange (ETDEWEB)

    Siegel, Alexander R. [Univ. of California, Berkeley, CA (United States); Wemmer, David E. [Univ. of California, Berkeley, CA (United States)

    2016-10-11

    Bacterial sigma factors are subunits of RNA polymerase that direct the holoenzyme to specific sets of promoters in the genome and are a central element of regulating transcription. Most polymerase holoenzymes open the promoter and initiate transcription rapidly after binding. However, polymerase containing the members of the σ54 family must be acted on by a transcriptional activator before DNA opening and initiation occur. A key domain in these transcriptional activators forms a hexameric AAA + ATPase that acts through conformational changes brought on by ATP hydrolysis. Contacts between the transcriptional activator and σ54 are primarily made through an N-terminal σ54 activator interacting domain (AID). To better understand this mechanism of bacterial transcription initiation, we characterized the σ54 AID by NMR spectroscopy and other biophysical methods and show that it is an intrinsically disordered domain in σ54 alone. In this paper, we identified a minimal construct of the Aquifex aeolicus σ54 AID that consists of two predicted helices and retains native-like binding affinity for the transcriptional activator NtrC1. Using the NtrC1 ATPase domain, bound with the non-hydrolyzable ATP analog ADP-beryllium fluoride, we studied the NtrC1–σ54 AID complex using NMR spectroscopy. We show that the σ54 AID becomes structured after associating with the core loops of the transcriptional activators in their ATP state and that the primary site of the interaction is the first predicted helix. Finally, understanding this complex, formed as the first step toward initiation, will help unravel the mechanism of σ54 bacterial transcription initiation.

  19. Isolation of Biosurfactant–Producing Bacteria with Antimicrobial Activity against Bacterial Pathogens

    Directory of Open Access Journals (Sweden)

    Siripun Sarin

    2011-01-01

    Full Text Available The aims of this research were to study biosurfactant producing bacteria isolated from soil and to determine their property and efficiency as biosurfactants in order to inhibit bacterial pathogens. The result showed that there were 8 bacterial isolates out of 136 isolates of the total biosurfactant producing bacteria screened that exhibited the diameter of clear zone more than 1.5 cm. in the oil spreading test. The highest potential of emulsifying activity (%EA24 of 54.4 and the maximum additive concentration, (%MAC of 24.2 was obtained from the fermentation broth of the G7 isolate which the G7 isolate was later identified as Pseudomonas fluorescens. Escherichia coli, Staphylococcus aureus and Psuedomonas aeruginosa were the tested bacterial pathogens that were most sensitive to the acid precipitated biosurfactant obtained from P. fluorescens G7 with the lowest minimum inhibitory concentration (MIC of 41.6 mg/ml and minimum bactericidal concentration (MBC of 41.6 mg/ml compared with the acid precipitated bisurfactants of the other isolates used in the antimicrobial activity test. The type of the separated crude biosurfactant produced by P. fluorescens G7 analyzed later by using the rhamose test, TLC and FT-IR techniques was rhamnolipid.

  20. Diversity, antimicrobial and antioxidant activities of culturable bacterial endophyte communities in Aloe vera.

    Science.gov (United States)

    Akinsanya, Mushafau Adewale; Goh, Joo Kheng; Lim, Siew Ping; Ting, Adeline Su Yien

    2015-12-01

    Twenty-nine culturable bacterial endophytes were isolated from surface-sterilized tissues (root, stem and leaf) of Aloe vera and molecularly characterized to 13 genera: Pseudomonas, Bacillus, Enterobacter, Pantoea, Chryseobacterium, Sphingobacterium, Aeromonas, Providencia, Cedecea, Klebsiella, Cronobacter, Macrococcus and Shigella. The dominant genera include Bacillus (20.7%), Pseudomonas (20.7%) and Enterobacter (13.8%). The crude and ethyl acetate fractions of the metabolites of six isolates, species of Pseudomonas, Bacillus, Chryseobacterium and Shigella, have broad spectral antimicrobial activities against pathogenic Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus, Salmonella Typhimurium, Proteus vulgaris, Klebsiella pneumoniae, Escherichia coli, Streptococcus pyogenes and Candida albicans, with inhibition zones ranging from 6.0 ± 0.57 to 16.6 ± 0.57 mm. In addition, 80% of the bacterial endophytes produced 1,1-diphenyl-2-picrylhydrazyl (DPPH) with scavenging properties of over 75% when their crude metabolites were compared with ascorbic acid (92%). In conclusion, this study revealed for the first time the endophytic bacteria communities from A. vera (Pseudomonas hibiscicola, Macrococcus caseolyticus, Enterobacter ludwigii, Bacillus anthracis) that produce bioactive compounds with high DPPH scavenging properties (75-88%) and (Bacillus tequilensis, Pseudomonas entomophila, Chryseobacterium indologenes, Bacillus aerophilus) that produce bioactive compounds with antimicrobial activities against bacterial pathogens. Hence, we suggest further investigation and characterization of their bioactive compounds.

  1. Surface activation of graphene oxide nanosheets by ultraviolet irradiation for highly efficient anti-bacterials

    Science.gov (United States)

    Veerapandian, Murugan; Zhang, Linghe; Krishnamoorthy, Karthikeyan; Yun, Kyusik

    2013-10-01

    A comprehensive investigation of anti-bacterial properties of graphene oxide (GO) and ultraviolet (UV) irradiated GO nanosheets was carried out. Microscopic characterization revealed that the GO nanosheet-like structures had wavy features and wrinkles or thin grooves. Fundamental surface chemical states of GO nanosheets (before and after UV irradiation) were investigated using x-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy. Minimum inhibitory concentration (MIC) results revealed that UV irradiated GO nanosheets have more pronounced anti-bacterial behavior than GO nanosheets and standard antibiotic, kanamycin. The MIC of UV irradiated GO nanosheets was 0.125 μg ml-1 for Escherichia coli and Salmonella typhimurium, 0.25 μg ml-1 for Bacillus subtilis and 0.5 μg ml-1 for Enterococcus faecalis, ensuring its potential as an anti-infective agent for controlling the growth of pathogenic bacteria. The minimum bactericidal concentration of normal GO nanosheets was determined to be two-fold higher than its corresponding MIC value, indicating promising bactericidal activity. The mechanism of anti-bacterial action was evaluated by measuring the enzymatic activity of β-d-galactosidase for the hydrolysis of o-nitrophenol-β-d-galactopyranoside.

  2. Nano-TiO2 affects Cu speciation, extracellular enzyme activity, and bacterial communities in sediments.

    Science.gov (United States)

    Fan, Wenhong; Liu, Tong; Li, Xiaomin; Peng, Ruishuang; Zhang, Yilin

    2016-11-01

    In aquatic ecosystems, titanium dioxide nanoparticles (nano-TiO2) coexist with heavy metals and influence the existing forms and toxicities of the metal in water. However, limited information is available regarding the ecological risk of this coexistence in sediments. In this study, the effect of nano-TiO2 on Cu speciation in sediments was investigated using sequential extraction. The microcosm approach was also employed to analyze the effects of the coexistence of nano-TiO2 and Cu on extracellular enzyme activity and bacterial communities in sediments. Results showed that nano-TiO2 decreased the organic matter-bound fraction of Cu and increased the corresponding residual fraction Cu. As a result, speciation of exogenous Cu in sediments changed. During the course of the 30-day experiment, the presence of nano-TiO2 did not affect Cu-induced changes in bacterial community structure. However, the coexistence of nano-TiO2 and Cu restrained the activity of bacterial extracellular enzymes, such as alkaline phosphatase and β-glucosidase. The degree of inhibition also varied because of the different properties of extracellular enzymes. This research highlighted the importance of understanding and predicting the effects of the coexistence of nanomaterials and other pollutants in sediments.

  3. Bacterial expression of an active class Ib chitinase from Castanea sativa cotyledons.

    Science.gov (United States)

    Allona, I; Collada, C; Casado, R; Paz-Ares, J; Aragoncillo, C

    1996-12-01

    Ch3, an endochitinase of 32 kDa present in Castanea sativa cotyledons, showed in vitro antifungal properties when assayed against Trichoderma viride. The characterization of a cDNA clone corresponding to this protein indicated that Ch3 is a class Ib endochitinase that is synthesized as a preprotein with a signal sequence preceding the mature polypeptide. Bacterial expression of mature Ch3 fused to the leader peptide of the periplasmic protein ompT resulted in active Ch3 enzyme. A plate assay was adapted for semi-quantitative determination of chitinase activity secreted from cultured bacteria, which should facilitate the identification of mutants with altered capacity to hydrolyse chitin.

  4. [BACILLUS STRAINS'S SCREENING--ACTIVE ANTAGONISTS OF BACTERIAL AND FUNGAL PHYTOPATHOGENS].

    Science.gov (United States)

    Grabova, A Yu; Dragovoz, I V; Kruchkova, L A; Pasichnik, L A; Avdeeva, L V

    2015-01-01

    Antagonistic activity 100 strains of Bacillus bacteria towards to museum and actual strains of phytopathogenic bacteria and fungy was defined. Relation between level of antagonistic activity to phytopathogenic bacteria and genus accessory of the last was shown. The medium level of antagonism to fungal phytopathogens at 30% of the studied strains of Bacillus bacteria was shown. 5 strains of Bacillus sp. with high and medium levels of antagonism to phytopathogens bacterial and fungy nature was selected and considered as perspective for creation of biological preparations for plant protection.

  5. Phylogenetic relationship and antifouling activity of bacterial epiphytes from the marine alga Ulva lactuca.

    Science.gov (United States)

    Egan, S; Thomas, T; Holmström, C; Kjelleberg, S

    2000-06-01

    It is widely accepted that bacterial epiphytes can inhibit the colonization of surfaces by common fouling organisms. However, little information is available regarding the diversity and properties of these antifouling bacteria. This study assessed the antifouling traits of five epiphytes of the common green alga, Ulva lactuca. All isolates were capable of preventing the settlement of invertebrate larvae and germination of algal spores. Three of the isolates also inhibited the growth of a variety of bacteria and fungi. Their phylogenetic positions were determined by 16S ribosomal subunit DNA sequencing. All isolates showed a close affiliation with the genus Pseudoalteromonas and, in particular, with the species P. tunicata. Strains of this bacterial species also display a variety of antifouling activities, suggesting that antifouling ability may be an important trait for members of this genus to be highly successful colonizers of animate surfaces and for such species to protect their host against fouling.

  6. Biological Activity of Sour Cherry Fruit on the Bacterial Flora of Human Saliva in vitro

    Directory of Open Access Journals (Sweden)

    Anna Blázovics

    2012-01-01

    Full Text Available This study is the first report on the antibacterial effect of Hungarian sour cherry cultivars. Biological activity of sour cherry juices prepared from fruits Érdi jubileum, Érdi bőtermő, Maliga emléke and Kántorjánosi 3 harvested at different maturity stages was investigated on bacteria present in human saliva. The influence of sour cherry on a mixed bacterial flora of human saliva of 10 volunteers was determined by different experimental approaches. Bactericidal effects were evaluated by minimum inhibitory concentration (MIC using agar diffusion methods and by minimum bactericidal dilution (MBD assays counting the number of surviving bacterial cells in the diluted juices. Time-dependent antibacterial effects were also determined by monitoring the decrease in bacterial cell numbers after the treatment with undiluted juices. The investigated sour cherry juices displayed an impressive bactericidal effect against human saliva bacteria (10–100× reduction of cell numbers within a short time frame (10–40 min. Érdi jubileum was more effective (100 000× reduction of cell number after 270 min than the other studied cultivars. Bactericidal effect was influenced by ripening of samples of Érdi jubileum obtained at different harvesting dates. Biologically active components were effective against a large spectrum of opportunistic bacterial pathogens such as Pseudomonas, Klebsiella, Pantoea spp. and Escherichia coli, including the antibiotic-resistant Pseudomonas aeruginosa but they were ineffective against beneficial probiotic Lactobacillus spp. Results confirmed the antibacterial potential of all the investigated sour cherry fruits, therefore the consumption of the fruit or its juice for positive influence on oral hygiene is highly recommended.

  7. Effects of Biochar Amendment on Tomato Bacterial Wilt Resistance and Soil Microbial Amount and Activity

    Directory of Open Access Journals (Sweden)

    Yang Lu

    2016-01-01

    Full Text Available Bacterial wilt is a serious soilborne disease of Solanaceae crops which is caused by Ralstonia solanacearum. The important role of biochar in enhancing disease resistance in plants has been verified; however, the underlying mechanism remains not fully understood. In this study, two different biochars, made from peanut shell (BC1 and wheat straw (BC2, were added to Ralstonia solanacearum-infected soil to explore the interrelation among biochar, tomato bacterial wilt, and soil microbial properties. The results showed that both BC1 and BC2 treatments significantly reduced the disease index of bacterial wilt by 28.6% and 65.7%, respectively. The populations of R. solanacearum in soil were also significantly decreased by biochar application. Ralstonia solanacearum infection significantly reduced the densities of soil bacteria and actinomycetes and increased the ratio of soil fungi/bacteria in the soil. By contrast, BC1 and BC2 addition to pathogen-infected soil significantly increased the densities of soil bacteria and actinomycetes but decreased the density of fungi and the ratios of soil fungi/bacteria and fungi/actinomycetes. Biochar treatments also increased soil neutral phosphatase and urease activity. Furthermore, higher metabolic capabilities of microorganisms by biochar application were found at 96 and 144 h in Biolog EcoPlates. These results suggest that both peanut and wheat biochar amendments were effective in inhibiting tomato bacterial wilt caused by R. solanacearum. The results suggest a relationship between the disease resistance of the plants and the changes in soil microbial population densities and activity.

  8. Caspase activation as a versatile assay platform for detection of cytotoxic bacterial toxins.

    Science.gov (United States)

    Payne, Angela M; Zorman, Julie; Horton, Melanie; Dubey, Sheri; ter Meulen, Jan; Vora, Kalpit A

    2013-09-01

    Pathogenic bacteria produce several virulence factors that help them establish infection in permissive hosts. Bacterial toxins are a major class of virulence factors and hence are attractive therapeutic targets for vaccine development. Here, we describe the development of a rapid, sensitive, and high-throughput assay that can be used as a versatile platform to measure the activities of bacterial toxins. We have exploited the ability of these toxins to cause cell death via apoptosis of sensitive cultured cell lines as a readout for measuring toxin activity. Caspases (cysteine-aspartic proteases) are induced early in the apoptotic pathway, and so we used their induction to measure the activities of Clostridium difficile toxins A (TcdA) and B (TcdB) and binary toxin (CDTa-CDTb), Corynebacterium diphtheriae toxin (DT), and Pseudomonas aeruginosa exotoxin A (PEA). Caspase induction in the cell lines, upon exposure to toxins, was optimized by toxin concentration and intoxication time, and the specificity of caspase activity was established using a genetically mutated toxin and a pan-caspase inhibitor. In addition, we demonstrate the utility of the caspase assay for measuring toxin potency, as well as neutralizing antibody (NAb) activity against C. difficile toxins. Furthermore, the caspase assay showed excellent correlation with the filamentous actin (F-actin) polymerization assay for measuring TcdA and TcdB neutralization titers upon vaccination of hamsters. These results demonstrate that the detection of caspase induction due to toxin exposure using a chemiluminescence readout can support potency and clinical immunogenicity testing for bacterial toxin vaccine candidates in development.

  9. Influence of azo dye concentration on activated sludge bacterial community in the presence of functionalized polyurethane foam.

    Science.gov (United States)

    Lu, Hong; Wang, Jing; Lu, Shuilong; Wang, Ying; Liu, Guangfei; Zhou, Jiti; Quan, Zhexue

    2015-03-01

    Immobilized quinones exhibit good catalytic performance in the biodecolorization of azo dyes. However, in practical activated sludge systems, little is known about the effect of azo dye concentration on microbial communities in the presence of immobilized quinones. 454 Pyrosequencing was used to investigate structural changes and to determine the key microorganisms involved in Reactive Red X-3B decolorization in the presence of anthraquinone-2-sulfonate immobilized on polyurethane foam (AQS-PUF). Our results show that the AQS-PUF-supplemented system exhibited better stability and decolorization performance during a 30-day run than polyurethane-foam-only (PUF-supplemented) and control systems. Analysis of pyrosequencing data showed that the AQS-PUF-supplemented system had the highest bacterial diversity, followed by the control and PUF-supplemented systems during decolorization. Reactive Red X-3B and AQS-PUF significantly influenced bacterial communities at the class level: Erysipelotrichia and the most dominant Deltaproteobacteria showed significant positive correlations with Reactive Red X-3B, while unclassified Firmicutes were found to be significantly correlated with AQS-PUF. At the genus level, Desulfomicrobium, which represents 8-44 % of the total population, displayed a significant positive correlation with Reactive Red X-3B. Some bacteria, including Desulfovibrio, Shewanella, and Clostridium with relative abundances of less than 6 %, were positively correlated with AQS-PUF. These findings provide a novel insight into the changes that occur in the bacterial community during immobilized AQS-mediated decolorization. Less abundant quinone-reducing bacteria play important roles in accelerating the effect of AQS-PUF on biodecolorization.

  10. Extracurricular Activity Involvement and Adolescent Self-Esteem

    Science.gov (United States)

    Kort-Butler, Lisa A.

    2012-01-01

    Structured extracurricular activity participation has been linked to self-esteem and other indicators of positive youth development. This article describes the theoretical basis for this relationship, centering on extracurricular activities as a location for identity development. A summary of the empirical evidence points to the importance of…

  11. Extracurricular Activity Involvement and Adolescent Self-Esteem

    Science.gov (United States)

    Kort-Butler, Lisa A.

    2012-01-01

    Structured extracurricular activity participation has been linked to self-esteem and other indicators of positive youth development. This article describes the theoretical basis for this relationship, centering on extracurricular activities as a location for identity development. A summary of the empirical evidence points to the importance of…

  12. 101 Activities for Building More Effective School-Community Involvement.

    Science.gov (United States)

    Rich, Dorothy; Mattox, Beverly

    This booklet contains a collection of more than 100 activities designed to promote school-home and school-community relations. Activities are organized into seven categories: (1) communicating word from home to school, (2) people to people, (3) educational events, (4) volunteers--hands on in the classroom, (5) utilizing community resources, (6)…

  13. Antimicrobial proteins from snake venoms: direct bacterial damage and activation of innate immunity against Staphylococcus aureus skin infection.

    Science.gov (United States)

    Samy, R P; Stiles, B G; Gopalakrishnakone, P; Chow, V T K

    2011-01-01

    The innate immune system is the first line of defense against microbial diseases. Antimicrobial proteins produced by snake venoms have recently attracted significant attention due to their relevance to bacterial infection and potential development into new therapeutic agents. Staphylococcus aureus is one of the major human pathogens causing a variety of infections involving pneumonia, toxic shock syndrome, and skin lesions. With the recent emergence of methicillin (MRSA) and vancomycin (VRSA) resistance, S. aureus infection is a serious clinical problem that will have a grave socio-economic impact in the near future. Although S. aureus susceptibility to innate antimicrobial peptides has been reported recently, the protective effect of snake venom phospholipase A₂ (svPLA₂) proteins on the skin from S. aureus infection has been understudied. This review details the protective function of svPLA₂s derived from venoms against skin infections caused by S. aureus. We have demonstrated in vivo that local application of svPLA₂ provides complete clearance of S. aureus within 2 weeks after treatment compared to fusidic acid ointment (FAO). In vitro experiments also demonstrate that svPLA₂ proteins have inhibitory (bacteriostatic) and killing (bactericidal) effects on S. aureus in a dose-dependant manner. The mechanism of bacterial membrane damage and perturbation was clearly evidenced by electron microscopic studies. In summary, svPLA₂s from Viperidae and Elapidae snakes are novel molecules that can activate important mechanisms of innate immunity in animals to endow them with protection against skin infection caused by S. aureus.

  14. Germa-gamma-lactones as novel inhibitors of bacterial urease activity.

    Science.gov (United States)

    Amtul, Zareen; Follmer, Cristian; Mahboob, Sumera; Atta-Ur-Rahman; Mazhar, Muhammad; Khan, Khalid M; Siddiqui, Rafat A; Muhammad, Sajjad; Kazmi, Syed A; Choudhary, Mohammad Iqbal

    2007-05-04

    Organogermanium compounds have been used as pharmacological agents. However, very few reports are available on the synthesis and antibacterial activities of lactones containing organogermaniums. The purpose of the present investigation was to determine the effects of different lactone-substituted organogermaniums on bacterial growth and their urease activity. We report synthesis of 12 germa-gamma-lactones (GeL) and their antimicrobial activities against several bacterial pathogens. Antibacterial action of all GeL was highly selective against Gram-negative bacilli, particularly Proteus mirabilis, an important pathogen infecting the urinary tract. Furthermore, our data indicate that 8-quinoline derivatives were more potent against P. mirabilis than 2-methyl-8-quinoline. For example, the beta-(o-methylphenyl)-gamma,gamma-bis(8-quinolinoxy)germa-gamma-lactone and beta-(o-methoxyphenyl)-gamma,gamma-bis(8-quinolinoxy)germa-gamma-lactone were maximally active with MIC(90) of 61 and 94 microM, respectively. In vitro studies demonstrated a linear correlation between antibacterial activity and inhibition of P. mirabilis urease enzyme. Further kinetic analyses revealed that inhibition occurred in a noncompetitive and concentration-dependent manner with the minimum IC(50) of 31 microM for beta-(o-methoxyphenyl)-gamma,gamma-bis(8-quinolinoxy)germa-gamma-lactone. In conclusion, these findings suggest that GeL have potential to be developed as antimicrobial agents against P. mirabilis infection.

  15. Bacterial DNA induces the complement system activation in serum and ascitic fluid from patients with advanced cirrhosis.

    Science.gov (United States)

    Francés, Rubén; González-Navajas, José M; Zapater, Pedro; Muñoz, Carlos; Caño, Rocío; Pascual, Sonia; Márquez, Dorkas; Santana, Francia; Pérez-Mateo, Miguel; Such, José

    2007-07-01

    Translocation of intestinal bacteria to ascitic fluid is, probably, the first step in the development of spontaneous bacterial peritonitis in patients with cirrhosis. Proteins of the complement system are soluble mediators implicated in the host immune response to bacterial infections and its activation has been traditionally considered to be an endotoxin-induced phenomenon. The aim of this study was to compare the modulation of these proteins in response to the presence of bacterial DNA and/or endotoxin in patients with advanced cirrhosis and ascites in different clinical conditions. Groups I and II consisted of patients without/with bacterial DNA. Group III included patients with spontaneous bacterial peritonitis and Group IV with patients receiving norfloxacin as secondary long-term prophylaxis of spontaneous bacterial peritonitis. Serum and ascitic fluid levels of endotoxin and truncated residues of the complement system were measured by ELISA. The complement system is triggered in response to bacterial DNA, as evidenced by significantly increased levels of C3b, membrane attack complex, and C5a in patients from Groups II and III compared with patients without bacterial DNA (Group I) and those receiving norfloxacin (Group IV). Gram classification did not further differentiate the immune response between patients within groups II and III, even though endotoxin levels were, as expected, significantly higher in patients with bacterial DNA from gram-negative microorganisms. The complement protein activation observed in patients with bacterial DNA in blood and ascitic fluid is indistinguishable from that observed in patients with spontaneous bacterial peritonitis and may occur in an endotoxin-independent manner.

  16. Bacterial production, glucosidase activity and particle-associated carbohydrates in Dona Paula bay, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Bhaskar, P.V.; Bhosle, N.B.

    Size-fractionated bacterial production, abundance and Alpha - and Beta - glucosidase enzyme activities were studied with respect to changes in hydrography, total suspended matter (TSM), chlorophyll a, particulate organic carbon and nitrogen ratio...

  17. Influence of salt marsh on bacterial activity in two estuaries with different hydrodynamic characteristics (Ria de Aveiro and Tagus Estuary).

    Science.gov (United States)

    Santos, Luísa; Cunha, Angela; Silva, Helena; Caçador, Isabel; Dias, Joao M; Almeida, Adelaide

    2007-06-01

    The influence of salt marsh on estuarine bacterioplankton was investigated in two estuaries with different hydrodynamic characteristics (Ria de Aveiro and Tagus Estuary). In the Ria de Aveiro, bacteria in the flood water overlying the marsh were two times more abundant and five to six times more active than in the main channel. In the Tagus Estuary, bacterial abundance was similar in flooding and channel water, but bacterial activity was up to two times higher in the main channel. The two salt marshes have distinct influences on estuarine bacterioplankton abundance and activity. In the Ria de Aveiro, salt marsh enhanced estuarine bacterial communities, increasing their size and stimulating their activity. By contrast, the salt marsh in the Tagus Estuary does not seem to increase the bacterial abundance and production in the channel water. These distinct influences may be explained by the hydrodynamic characteristics of the salt marshes, which were confirmed by the hydrodynamic model implemented for both systems.

  18. Mastitis and fertility in cattle - possible involvement of inflammation or immune activation in embryonic mortality.

    Science.gov (United States)

    Hansen, Peter J; Soto, Paolete; Natzke, Roger P

    2004-04-01

    Causes for pre-implantation embryo loss, which can be as high as 50% or more of fertilized embryos, are multifactorial and largely undescribed. Studies in cattle using mastitis as a model indicate that one cause of early embryonic loss is infectious disease or activation of immune responses at sites outside the reproductive tract. Infection of the mammary gland in dairy cattle is associated with a reduction in pregnancy rate (proportion of inseminated cows that become pregnant) and an increase in the number of inseminations required to establish pregnancy. Also, intravenous challenge with bacterial peptidoglycan and polysaccharide at approximately days 3-5 after breeding reduced subsequent pregnancy rate in sheep that had been previously immunized against the same material. The mechanism by which extrauterine activation of immune and inflammatory responses leads to embryonic loss is not clear although cytokines probably play a crucial role. Effects could be exerted at the level of the hypothalamic-pituitary axis, ovary, reproductive tract or embryo. Interferon (IFN)-alpha, for example, which can reduce pregnancy rate in cattle when injected around 13-19 days after breeding, increases body temperature, inhibits secretion of luteinizing hormone, and reduces circulating concentrations of progesterone. Other cytokines or products of cytokine activation could cause embryonic loss by causing hyperthermia (as elevated temperature blocks oocyte function and embryonic development), exerting toxic effects on the corpus luteum [for example, IFN-gamma, tumor necrosis factor-alpha (TNF-alpha) and prostaglandin F(2alpha)], stimulating endometrial prostaglandin synthesis [TNF-alpha and interleukin(IL)-1beta], reducing endometrial cell proliferation (IL-1beta), and interfering with oocyte maturation and embryonic development (TNF-alpha, nitric oxide, and prostaglandin F(2alpha)). Although largely neglected by reproductive immunologists, study of the involvement of the immune

  19. Infectious prosthetic hip joint loosening: bacterial species involved in its aetiology and their antibiotic resistance profiles against antibiotics recommended for the therapy of implant-associated infections.

    Science.gov (United States)

    Bogut, Agnieszka; Niedźwiadek, Justyna; Strzelec-Nowak, Dagmara; Blacha, Jan; Mazurkiewicz, Tomasz; Marczyński, Wojciech; Kozioł-Montewka, Maria

    2014-04-01

    Reliable microbiological diagnosis along with surgery and prolonged antibiotic therapy are key elements in the management of prosthetic-joint infections (PJIs). The purpose of this study was to characterize antibiotic resistance profiles of bacteria involved in the aetiology of PJIs. A total of 33 bacterial isolates cultured from 31 patients undergoing exchange of total hip prostheses were analyzed. The diagnostic approach toward isolation of prosthesis- associated microorganisms included sonication of retrieved implants and conventional cultures of periprosthetic tissues and synovial fluid. The in vitro resistance profiles of bacterial isolates were determined in relation to antibiotics recommended for the therapy of PJIs using the disc diffusion method, E-tests(®) and broth microdilution system. Coagulase-negative staphylococci (CNS) were predominant microorganisms followed by Staphylococcus aureus, Enterobacter cloacae, Streptococcus mitis, and Propionibacterium acnes. Twenty out of 30 and 12 out of 30 staphylococcal isolates were methicillin- and multi-drug resistant, respectively. Only two isolates were rifampicinresistant. All staphylococci were susceptible to glycopeptides and linezolid. This paper stresses the pathogenic role of staphylococci in patients suffering from implant loosening and reports high methicillin- and multidrug-resistance rates in these bacteria. Hence, antimicrobial susceptibility tests of individual bacterial isolates must always be performed to guide selection of the optimal therapeutic option.

  20. Flow and active mixing have a strong impact on bacterial growth dynamics in the proximal large intestine

    Science.gov (United States)

    Cremer, Jonas; Segota, Igor; Yang, Chih-Yu; Arnoldini, Markus; Groisman, Alex; Hwa, Terence

    2016-11-01

    More than half of fecal dry weight is bacterial mass with bacterial densities reaching up to 1012 cells per gram. Mostly, these bacteria grow in the proximal large intestine where lateral flow along the intestine is strong: flow can in principal lead to a washout of bacteria from the proximal large intestine. Active mixing by contractions of the intestinal wall together with bacterial growth might counteract such a washout and allow high bacterial densities to occur. As a step towards understanding bacterial growth in the presence of mixing and flow, we constructed an in-vitro setup where controlled wall-deformations of a channel emulate contractions. We investigate growth along the channel under a steady nutrient inflow. Depending on mixing and flow, we observe varying spatial gradients in bacterial density along the channel. Active mixing by deformations of the channel wall is shown to be crucial in maintaining a steady-state bacterial population in the presence of flow. The growth-dynamics is quantitatively captured by a simple mathematical model, with the effect of mixing described by an effective diffusion term. Based on this model, we discuss bacterial growth dynamics in the human large intestine using flow- and mixing-behavior having been observed for humans.

  1. Anti-acne-inducing bacterial activity of mangosteen fruit rind extracts.

    Science.gov (United States)

    Pothitirat, Werayut; Chomnawang, Mullika Traidej; Gritsanapan, Wandee

    2010-01-01

    The aims of this study were to determine the most effective solvent extract of mangosteen, anti-acne- inducing bacterial activity and the amount of alpha-mangostin, a major active component in each mangosteen fruit rind extract, using high-performance liquid chromatography (HPLC). The fruit rinds of mangosteen were extracted with hexane, dichloromethane, ethanol and water. The extracts were tested for antibacterial activity against bacteria that induce acne, including Propionibacterium acnes and Staphylococcus epidermidis. Thin-layer chromatographic autobiography against these bacteria was also performed for each extract, while the alpha-mangostin content was analyzed using a validated HPLC method. The dichloromethane extract exhibited the strongest antibacterial effect with minimum inhibitory concentration values for both bacterial species at 3.91 microg/ml, while the minimum bactericidal concentration values against P. acnes and S. epidermidis were 3.91 and 15.63 microg/ml, respectively. Thin-layer chromatographic autobiography indicated that alpha-mangostin was present in all extracts, except the water extract, and is a major active component against both P. acnes and S. epidermidis. Using HPLC, the dichloromethane extract yielded the highest content (46.21% w/w) of alpha-mangostin followed by the ethanol extract (18.03% w/w), the hexane extract (17.21% w/w) and the water extract (0.54% w/w). Dichloromethane extract exhibited the strongest anti-acne-inducing bacterial effect and this extract yielded the highest amount of alpha-mangostin. Copyright 2010 S. Karger AG, Basel.

  2. Comparison of Hemagglutination and Hemolytic Activity of Various Bacterial Clinical Isolates Against Different Human Blood Groups

    Science.gov (United States)

    HRV, Rajkumar; Devaki, Ramakrishna

    2016-01-01

    Among the various pathogenic determinants shown by microorganisms hemagglutination and hemolysin production assume greater significance in terms of laboratory identification. This study evaluated the hemagglutination and hemolytic activity of various bacterial isolates against different blood groups. One hundred and fifty bacterial strains, isolated from clinical specimens like urine, pus, blood, and other body fluids were tested for their hemagglutinating and hemolytic activity against human A, B, AB, and O group red blood cells. Among the 150 isolates 81 were Escherichia coli, 18 were Klebsiella pneumoniae, 19 were Pseudomonas aeruginosa, 10 were Pseudomonas spp, six were Proteus mirabilis, and the rest 16 were Staphylococcus aureus. Nearly 85% of the isolates agglutinated A group cells followed by B and AB group (59.3% and 60.6% respectively). Least number of isolates agglutinated O group cells (38.0%). When the hemolytic activity was tested, out of these 150 isolates 79 (52.6%) hemolyzed A group cells, 61 (40.6%) hemolyzed AB group cells, 46 (30.6%) hemolyzed B group cells, and 57 (38.6%) isolates hemolyzed O group cells. Forty-six percent of the isolates exhibited both hemagglutinating and hemolytic property against A group cells, followed by B and AB group cells (28.6% and 21.3% respectively). Least number of isolates i.e., 32 (21.3%) showed both the properties against O group cells. The isolates showed wide variation in their hemagglutination and hemolytic properties against different combinations of human blood group cells. The study highlights the importance of selection of the type of cells especially when human RBCs are used for studying the hemagglutination and hemolytic activity of bacterial isolates because these two properties are considered as characteristic of pathogenic strains. PMID:27014523

  3. The AS87_04050 gene is involved in bacterial lipopolysaccharide biosynthesis and pathogenicity of Riemerella anatipestifer.

    Directory of Open Access Journals (Sweden)

    Xiaolan Wang

    Full Text Available Riemerella anatipestifer is reported worldwide as a cause of septicemic and exudative diseases of domestic ducks. In this study, we identified a mutant strain RA2640 by Tn4351 transposon mutagenesis, in which the AS87_04050 gene was inactivated by insertion of the transposon. Southern blot analysis indicated that only one insertion was found in the genome of the mutant strain RA2640. SDS-PAGE followed by silver staining showed that the lipopolysaccharide (LPS pattern of mutant strain RA2640 was different from its wild-type strain Yb2, suggesting the LPS was defected. In addition, the phenotype of the mutant strain RA2640 was changed to rough-type, evident by altered colony morphology, autoaggregation ability and crystal violet staining characteristics. Bacterial LPS is a key factor in virulence as well as in both innate and acquired host responses to infection. The rough-type mutant strain RA2640 showed higher sensitivity to antibiotics, disinfectants and normal duck serum, and higher capability of adherence and invasion to Vero cells, compared to its wild-type strain Yb2. Moreover, the mutant strain RA2640 lost the agglutination ability of its wild-type strain Yb2 to R. anatipestifer serotype 2 positive sera, suggesting that the O-antigen is defected. Animal experiments indicated that the virulence of the mutant strain RA2640 was attenuated by more than 100,000-fold, compared to its wild-type strain Yb2. These results suggested that the AS87_04050 gene in R. anatipestifer is associated with the LPS biosynthesis and bacterial pathogenicity.

  4. Structural basis for the reversible activation of a Rho protein by the bacterial toxin SopE

    OpenAIRE

    Buchwald, Gretel; Friebel, Andrea; Galán, Jorge E.; Hardt, Wolf-Dietrich; Wittinghofer, Alfred; Scheffzek, Klaus

    2002-01-01

    The bacterial enteropathogen Salmonella typhimurium employs a type III secretion system to inject bacterial toxins into the host cell cytosol. These toxins transiently activate Rho family GTP-binding protein-dependent signaling cascades to induce cytoskeletal rearrangements. One of these translocated Salmonella toxins, SopE, can activate Cdc42 in a Dbl-like fashion despite its lack of sequence similarity to Dbl-like proteins, the Rho-specific eukaryotic guanine nucleotide exchange factors. To...

  5. Bacterial Community Structure Shifted by Geosmin in Granular Activated Carbon System of Water Treatment Plants.

    Science.gov (United States)

    Pham, Ngoc Dung; Lee, Eun-Hee; Chae, Seon-Ha; Cho, Yongdeok; Shin, Hyejin; Son, Ahjeong

    2016-01-01

    We investigated the relation between the presence of geosmin in water and the bacterial community structure within the granular activated carbon (GAC) system of water treatment plants in South Korea. GAC samples were collected in May and August of 2014 at three water treatment plants (Sungnam, Koyang, and Yeoncho in Korea). Dissolved organic carbon and geosmin were analyzed before and after GAC treatment. Geosmin was found in raw water from Sungnam and Koyang water treatment plants but not in that from Yeoncho water treatment plant. Interestingly, but not surprisingly, the 16S rRNA clone library indicated that the bacterial communities from the Sungnam and Koyang GAC systems were closely related to geosmin-degrading bacteria. Based on the phylogenetic tree and multidimensional scaling plot, bacterial clones from GAC under the influence of geosmin were clustered with Variovorax paradoxus strain DB 9b and Comamonas sp. DB mg. In other words, the presence of geosmin in water might have inevitably contributed to the growth of geosmin degraders within the respective GAC system.

  6. Effects of fumigation with metam-sodium on soil microbial biomass, respiration, nitrogen transformation, bacterial community diversity and genes encoding key enzymes involved in nitrogen cycling.

    Science.gov (United States)

    Li, Jun; Huang, Bin; Wang, Qiuxia; Li, Yuan; Fang, Wensheng; Han, Dawei; Yan, Dongdong; Guo, Meixia; Cao, Aocheng

    2017-11-15

    Metam-sodium (MS) is widely used as a soil pre-plant fumigant as methyl bromide is phased out of agriculture. However, the information about how fumigation with MS affects the soil microbial community is still limited. In this study, a 66-day-long experiment was conducted to ascertain the effects of MS on soil substrate-induced respiration (SIR), microbial biomass nitrogen (MBN), NH4(+)-N and NO3(-)-N concentrations, as well as the abundance of the total bacteria and fungi and the expression of genes involved in nitrogen cycling. In addition, 16S rRNA amplicon sequencing was used to investigate the effect of MS on the soil bacterial community. The half-lives of high and low doses of methyl isothiocyanate (MITC) are 10.51h and 9.93h, respectively. MS caused a short-term inhibition of SIR, MBN; had an accumulation effect on NH4(+)-N concentration in the short term; reduced the abundance of the total bacteria and fungi; and suppressed the expression of the nifH, AOA-amoA, anammox bacteria, nosZ, nirS, and narG. In addition, under the influence of MS, soil bacterial diversity decreased significantly in the long term, bacterial community structure was affected, and there was a shift in the predominant population; for example, some genera, such as Paenibacillus and Luteimonas, significantly increased in number. These changes in bacterial flora may be closely related to the growth of crops. Our study provides useful information for environmental safety assessments of MS in China. Copyright © 2017. Published by Elsevier B.V.

  7. Activation of brain endothelium by pneumococcal neuraminidase NanA promotes bacterial internalization.

    Science.gov (United States)

    Banerjee, Anirban; Van Sorge, Nina M; Sheen, Tamsin R; Uchiyama, Satoshi; Mitchell, Tim J; Doran, Kelly S

    2010-11-01

    Streptococcus pneumoniae (SPN), the leading cause of meningitis in children and adults worldwide, is associated with an overwhelming host inflammatory response and subsequent brain injury. Here we examine the global response of the blood-brain barrier to SPN infection and the role of neuraminidase A (NanA), an SPN surface anchored protein recently described to promote central nervous system tropism. Microarray analysis of human brain microvascular endothelial cells (hBMEC) during infection with SPN or an isogenic NanA-deficient (ΔnanA) mutant revealed differentially activated genes, including neutrophil chemoattractants IL-8, CXCL-1, CXCL-2. Studies using bacterial mutants, purified recombinant NanA proteins and in vivo neutrophil chemotaxis assays indicated that pneumococcal NanA is necessary and sufficient to activate host chemokine expression and neutrophil recruitment during infection. Chemokine induction was mapped to the NanA N-terminal lectin-binding domain with a limited contribution of the sialidase catalytic activity, and was not dependent on the invasive capability of the organism. Furthermore, pretreatment of hBMEC with recombinant NanA protein significantly increased bacterial invasion, suggesting that NanA-mediated activation of hBMEC is a prerequisite for efficient SPN invasion. These findings were corroborated in an acute murine infection model where we observed less inflammatory infiltrate and decreased chemokine expression following infection with the ΔnanA mutant.

  8. Macrophage activation induced by Brucella DNA suppresses bacterial intracellular replication via enhancing NO production.

    Science.gov (United States)

    Liu, Ning; Wang, Lin; Sun, Changjiang; Yang, Li; Tang, Bin; Sun, Wanchun; Peng, Qisheng

    2015-12-01

    Brucella DNA can be sensed by TLR9 on endosomal membrane and by cytosolic AIM2-inflammasome to induce proinflammatory cytokine production that contributes to partially activate innate immunity. Additionally, Brucella DNA has been identified to be able to act as a major bacterial component to induce type I IFN. However, the role of Brucella DNA in Brucella intracellular growth remains unknown. Here, we showed that stimulation with Brucella DNA promote macrophage activation in TLR9-dependent manner. Activated macrophages can suppresses wild type Brucella intracellular replication at early stage of infection via enhancing NO production. We also reported that activated macrophage promotes bactericidal function of macrophages infected with VirB-deficient Brucella at the early or late stage of infection. This study uncovers a novel function of Brucella DNA, which can help us further elucidate the mechanism of Brucella intracellular survival.

  9. Activation of the jasmonic acid plant defence pathway alters the composition of rhizosphere bacterial communities.

    Science.gov (United States)

    Carvalhais, Lilia C; Dennis, Paul G; Badri, Dayakar V; Tyson, Gene W; Vivanco, Jorge M; Schenk, Peer M

    2013-01-01

    Jasmonic acid (JA) signalling plays a central role in plant defences against necrotrophic pathogens and herbivorous insects, which afflict both roots and shoots. This pathway is also activated following the interaction with beneficial microbes that may lead to induced systemic resistance. Activation of the JA signalling pathway via application of methyl jasmonate (MeJA) alters the composition of carbon containing compounds released by roots, which are implicated as key determinants of rhizosphere microbial community structure. In this study, we investigated the influence of the JA defence signalling pathway activation in Arabidopsis thaliana on the structure of associated rhizosphere bacterial communities using 16S rRNA gene amplicon pyrosequencing. Application of MeJA did not directly influence bulk soil microbial communities but significant changes in rhizosphere community composition were observed upon activation of the jasmonate signalling pathway. Our results suggest that JA signalling may mediate plant-bacteria interactions in the soil upon necrotrophic pathogen and herbivorous insect attacks.

  10. Peptidomimetic Small Molecules Disrupt Type IV Secretion System Activity in Diverse Bacterial Pathogens

    Directory of Open Access Journals (Sweden)

    Carrie L. Shaffer

    2016-04-01

    Full Text Available Bacteria utilize complex type IV secretion systems (T4SSs to translocate diverse effector proteins or DNA into target cells. Despite the importance of T4SSs in bacterial pathogenesis, the mechanism by which these translocation machineries deliver cargo across the bacterial envelope remains poorly understood, and very few studies have investigated the use of synthetic molecules to disrupt T4SS-mediated transport. Here, we describe two synthetic small molecules (C10 and KSK85 that disrupt T4SS-dependent processes in multiple bacterial pathogens. Helicobacter pylori exploits a pilus appendage associated with the cag T4SS to inject an oncogenic effector protein (CagA and peptidoglycan into gastric epithelial cells. In H. pylori, KSK85 impedes biogenesis of the pilus appendage associated with the cag T4SS, while C10 disrupts cag T4SS activity without perturbing pilus assembly. In addition to the effects in H. pylori, we demonstrate that these compounds disrupt interbacterial DNA transfer by conjugative T4SSs in Escherichia coli and impede vir T4SS-mediated DNA delivery by Agrobacterium tumefaciens in a plant model of infection. Of note, C10 effectively disarmed dissemination of a derepressed IncF plasmid into a recipient bacterial population, thus demonstrating the potential of these compounds in mitigating the spread of antibiotic resistance determinants driven by conjugation. To our knowledge, this study is the first report of synthetic small molecules that impair delivery of both effector protein and DNA cargos by diverse T4SSs.

  11. Caspase-11 activation in response to bacterial secretion systems that access the host cytosol.

    Directory of Open Access Journals (Sweden)

    Cierra N Casson

    Full Text Available Inflammasome activation is important for antimicrobial defense because it induces cell death and regulates the secretion of IL-1 family cytokines, which play a critical role in inflammatory responses. The inflammasome activates caspase-1 to process and secrete IL-1β. However, the mechanisms governing IL-1α release are less clear. Recently, a non-canonical inflammasome was described that activates caspase-11 and mediates pyroptosis and release of IL-1α and IL-1β. Caspase-11 activation in response to Gram-negative bacteria requires Toll-like receptor 4 (TLR4 and TIR-domain-containing adaptor-inducing interferon-β (TRIF-dependent interferon production. Whether additional bacterial signals trigger caspase-11 activation is unknown. Many bacterial pathogens use specialized secretion systems to translocate effector proteins into the cytosol of host cells. These secretion systems can also deliver flagellin into the cytosol, which triggers caspase-1 activation and pyroptosis. However, even in the absence of flagellin, these secretion systems induce inflammasome activation and the release of IL-1α and IL-1β, but the inflammasome pathways that mediate this response are unclear. We observe rapid IL-1α and IL-1β release and cell death in response to the type IV or type III secretion systems of Legionella pneumophila and Yersinia pseudotuberculosis. Unlike IL-1β, IL-1α secretion does not require caspase-1. Instead, caspase-11 activation is required for both IL-1α secretion and cell death in response to the activity of these secretion systems. Interestingly, whereas caspase-11 promotes IL-1β release in response to the type IV secretion system through the NLRP3/ASC inflammasome, caspase-11-dependent release of IL-1α is independent of both the NAIP5/NLRC4 and NLRP3/ASC inflammasomes as well as TRIF and type I interferon signaling. Furthermore, we find both overlapping and non-redundant roles for IL-1α and IL-1β in mediating neutrophil recruitment

  12. Influence of hydrogen in the presence of organic matter on bacterial activity under radioactive waste disposal conditions

    Energy Technology Data Exchange (ETDEWEB)

    Chautard, C. [IRSN, PRP-DGE/SEDRAN/BERIS, B.P. 17, 92262 Fontenay-aux-Roses Cedex (France); CEA, DEN/DTN/SMTM/LMTE, bat 307, 13108 Saint Paul Lez Durance Cedex (France); Ritt, A. [IRSN, PRP-DGE/SRTG/LAME, B.P. 17, 92262 Fontenay-aux-Roses Cedex (France); Libert, M. [CEA, DEN/DTN/SMTM/LMTE, bat 307, 13108 Saint Paul Lez Durance Cedex (France); De Windt, L. [Mines-ParisTech, Geosciences Dpt., 77305 Fontainebleau Cedex (France)

    2013-07-01

    According to the French design for the disposal of high-level radioactive waste (HLW), waste will be emplaced in an environment involving metallic materials into a geological clay formation. The presence of microorganisms has recently been evidenced in such environments. Therefore, based on current knowledge, the introduction of microbial species during the construction and operational phases, as well as the survival of bacteria after the disposal closure, have to be accounted for within the context of safety assessment. Sulphate-reducing bacteria (SRB) activity is notably expected to have an impact on corrosion processes, and thus influence the evolution of metallic and clay materials involved in a HLW disposal cell. The present work investigates the potential development of a SRB, Thermo-desulfovibrio hydrogeniphilus, in order to better assess its metabolism in the presence of dissolved organic matter (DOM) that is representative of the DOM present in an argillaceous pore water, as well as hydrogen that will be produced by the anaerobic corrosion of metallic materials. After 49 days of batch experiments, hydrogen enhances the bacterial development in presence of a low amount of DOM, whereas the DOM alone does not seem to sustain bacteria activities. (authors)

  13. Particle emissions from laboratory activities involving carbon nanotubes

    Science.gov (United States)

    Lo, Li-Ming; Tsai, Candace S.-J.; Heitbrink, William A.; Dunn, Kevin H.; Topmiller, Jennifer; Ellenbecker, Michael

    2017-08-01

    This site study was conducted in a chemical laboratory to evaluate nanomaterial emissions from 20-30-nm-diameter bundles of single-walled carbon nanotubes (CNTs) during product development activities. Direct-reading instruments were used to monitor the tasks in real time, and airborne particles were collected using various methods to characterize released nanomaterials using electron microscopy and elemental carbon (EC) analyses. CNT clusters and a few high-aspect-ratio particles were identified as being released from some activities. The EC concentration (0.87 μg/m3) at the source of probe sonication was found to be higher than other activities including weighing, mixing, centrifugation, coating, and cutting. Various sampling methods all indicated different levels of CNTs from the activities; however, the sonication process was found to release the highest amounts of CNTs. It can be cautiously concluded that the task of probe sonication possibly released nanomaterials into the laboratory and posed a risk of surface contamination. Based on these results, the sonication of CNT suspension should be covered or conducted inside a ventilated enclosure with proper filtration or a glovebox to minimize the potential of exposure.

  14. 45 CFR 1177.4 - Claims involving criminal activity or misconduct.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 3 2010-10-01 2010-10-01 false Claims involving criminal activity or misconduct. 1177.4 Section 1177.4 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL... Claims involving criminal activity or misconduct. (a) A debtor whose indebtedness involves...

  15. Dopamine is involved in food-anticipatory activity in mice.

    Science.gov (United States)

    Liu, Yuan-Yuan; Liu, Tian-Ya; Qu, Wei-Min; Hong, Zong-Yuan; Urade, Yoshihiro; Huang, Zhi-Li

    2012-10-01

    When food is available during a restricted and predictable time of the day, mammals exhibit food-anticipatory activity (FAA), an increase in locomotor activity preceding the presentation of food. Although many studies have attempted to locate the food-entrainable circadian oscillator in the central nervous system, the pathways that mediate food entrainment are a matter of controversy. The present study was designed to determine the role of dopaminergic and histaminergic systems on FAA. Mice were given access to food for 2 h (ZT12-ZT14), and FAA was defined as the locomotor activity that occurred 2 h before the availability of food. Dopamine D(1) receptor (R), D(2)R, and histamine H(1)R-specific antagonists were used to clarify the role of dopamine and histamine receptors in FAA induced by food restriction (FR). FAA was monitored by infrared locomotor activity sensors. Mice were sacrificed at ZT12 on the 14th day of FR, and monoamine concentrations were determined by high-performance liquid chromatography coupled to electrochemical detection (HPLC-ECD). The results showed that pretreatment with the D(1)R antagonist SCH23390 at 1, 3, or 10 µg/kg significantly reduced FAA by 19% (p antagonist raclopride at 22, 67, or 200 µg/kg significantly reduced FAA by 16% (p dopamine and its metabolites in the striatum and midbrain were significantly increased during FAA, even with the pretreatment of D(1)R and D(2)R antagonists. However, pretreatment with pyrilamine at 2.5, 5, or 10 mg/kg did not significantly reduce FAA, although it reduced the locomotor activity during the dark period in ad libitum mice. These results strongly indicate that the dopaminergic system plays an essential role in the FAA in mice.

  16. Laccase activity is proportional to the abundance of bacterial laccase-like genes in soil from subtropical arable land.

    Science.gov (United States)

    Feng, Shuzhen; Su, Yirong; Dong, Mingzhe; He, Xunyang; Kumaresan, Deepak; O'Donnell, Anthony G; Wu, Jinshui; Chen, Xiangbi

    2015-12-01

    Laccase enzymes produced by both soil bacteria and fungi play important roles in refractory organic matter turnover in terrestrial ecosystems. We investigated the abundance and diversity of fungal laccase genes and bacterial laccase-like genes in soil from subtropical arable lands, and identified which microbial group was associated with laccase activity. Compared with fungal laccase genes, the bacterial laccase-like genes had greater abundance, richness and Shannon-Wiener diversity. More importantly, laccase activity can be explained almost exclusively by the bacterial laccase-like genes, and their abundance had significant linear relationship with laccase activity. Thus, bacterial laccase-like gene has great potential to be used as a sensitive indicator of laccase enzyme for refractory organic matter turnover in subtropical arable lands.

  17. Proposals for risk management in environments with activities involving nanomaterials

    Directory of Open Access Journals (Sweden)

    Luís Renato Balbão Andrade

    2013-11-01

    Full Text Available The handling of nanomaterials presents enormous challenges for risk management in research and production of new materials. However, data on the impacts of these new materials on human health and the environment need to be expanded. Several efforts have been made to mitigate the hardships and offer guidelines for the management of risks associated with nanomaterials. This article aims to provide a broad and comparing view of the main proposals in the literature. The methodology was systematic analysis encompassing 17 proposed risk management with nanomaterials. The results indicate that, although there is no consensus on the metrics used to characterize the risks of na-nomaterials, the adoption of the Precautionary Principle, the control banding approach and stakeholder involvement stands out among the documents analyzed.

  18. Addition of selenium nanoparticles to electrospun silk scaffolds improves mammalian cell activity while reducing bacterial growth

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    Stanley Chung

    2016-07-01

    Full Text Available Silk possesses many beneficial wound healing properties, and electrospun scaffolds are especially applicable for skin applications, due to their smaller interstices and higher surface areas compared to non-electrospun equivalents. However, purified silk promotes microbial growth. In contrast, selenium nanoparticles have excellent antibacterial properties and are a novel antimicrobial chemistry. Here, electrospun silk scaffolds were doped with selenium nanoparticles to impart antibacterial properties to the silk scaffolds. Results showed significantly improved bacterial inhibition and improvement in human dermal fibroblast metabolic activity. These results suggest that the addition of selenium nanoparticles to electrospun silk is a promising approach to improve wound healing with reduced infection, without relying on antibiotics.

  19. Efficient production of active chicken avidin using a bacterial signal peptide in Escherichia coli

    OpenAIRE

    Hytönen, Vesa P.; Laitinen, Olli H.; Airenne, Tomi T.; Kidron, Heidi; Meltola, Niko J.; Porkka, Eevaleena J.; Hörhä, Jarno; Paldanius, Tiina; Määttä, Juha A. E.; Nordlund, Henri R.; Johnson, Mark S.; Salminen, Tiina A.; Airenne, Kari J.; Ylä-Herttuala, Seppo; Kulomaa, Markku S.

    2004-01-01

    Chicken avidin is a highly popular tool with countless applications in the life sciences. In the present study, an efficient method for producing avidin protein in the periplasmic space of Escherichia coli in the active form is described. Avidin was produced by replacing the native signal sequence of the protein with a bacterial OmpA secretion signal. The yield after a single 2-iminobiotin–agarose affinity purification step was approx. 10 mg/l of virtually pure avidin. Purified avidin had 3.7...

  20. Bacterial pollution, activity and heterotrophic diversity of the northern part of the Aegean Sea, Turkey.

    Science.gov (United States)

    Çiftçi Türetken, Pelin S; Altuğ, Gülşen

    2016-02-01

    Isolation and characterization studies of marine heterotrophic bacteria are important to describe and understand eco-metobolism of the marine environments. In this study, diversity and community structures of the culturable heterotrophic bacteria, metabollicaly active bacteria and bacterial pollution in the coastal and offshore areas of Gökçeada Island, in the Northern Aegean Sea, Turkey were investigated from March 2012 to November 2013. The primary hydrographic parameters were recorded in situ. The frequency of the metabolically active bacteria was determined by using a modified staining technique. The indicator bacteria were determined by using membrane filtration technique; 126 bacteria isolates, 24 of them first records for this region, were identified using an automated micro-identification system, VITEK2 Compact30. The results showed that detected bacterial community profiles were significantly different when compared with previous studies conducted in polluted marine areas of Turkey. High frequency of faecal bacteria detected at station 2 indicated that increasing human activities and terrestrial pollution sources are shaping factors for possible risks, regarding recreational uses of this region, in the summer seasons.

  1. In vitro anti-biofilm and anti-bacterial activity of Junceella juncea for its biomedical application

    Institute of Scientific and Technical Information of China (English)

    P Kumar; S Senthamil Selvi; M Govindaraju

    2012-01-01

    Objective: To investigate the anti-biofilm and anti-bacterial activity of Junceella juncea (J. juncea) against biofilm forming pathogenic strains. Methods: Gorgonians were extracted with methanol and analysed with fourier transform infrared spectroscopy. Biofilm forming pathogens were identified by Congo red agar supplemented with sucrose. A quantitative spectrophotometric method was used to monitor in vitro biofilm reduction by microtitre plate assay. Anti-bacterial activity of methanolic gorgonian extract (MGE) was carried out by disc diffusion method followed by calculating the percentage of increase with crude methanol (CM). Results: The presence of active functional group was exemplified by FT-IR spectroscopy. Dry, black, crystalline colonies confirm the production of extracellular polymeric substances responsible for biofilm formation in Congo red agar. MGE exhibited potential anti-biofilm activity against all tested bacterial strains. The anti-bacterial activity of methanolic extract was comparably higher in Salmonella typhii followed by Escherichia coli, Vibrio cholerae and Shigella flexneri. The overall percentage of increase was higher by 50.2%to CM. Conclusions:To conclude, anti-biofilm and anti-bacterial efficacy of J. juncea is impressive over biofilm producing pathogens and are good source for novel anti-bacterial compounds.

  2. Responses of active bacterial and fungal communities in soils under winter wheat to different fertilizer and pesticide regimens.

    Science.gov (United States)

    Girvan, Martina S; Bullimore, Juliet; Ball, Andrew S; Pretty, Jules N; Osborn, A Mark

    2004-05-01

    The composition of the active microbial (bacterial and fungal) soil community in an arable wheat field subjected to different management practices was examined at five times during a 1-year period. Field sections were fertilized either at good agricultural practice (GAP) levels or at reduced levels (0.5x GAP) and were inoculated with vesicular arbuscular mycorrhizae (VAM) at the same time. Field subsections were treated either with or without pesticides. Changes in the active microbial communities were investigated by denaturing gradient gel electrophoresis analysis of reverse transcription-PCR-amplified 16S and 18S rRNA. Microbial community structure was primarily determined by season, and the seasonal trends were similar for the fungal and bacterial components. Between-sample microbial heterogeneity decreased under a mature crop in the summer but increased following harvesting and plowing. Although similar overall trends were seen for the two microbial components, sample variability was greater for the fungal community than for the bacterial community. The greatest management effects were due to GAP fertilization, which caused increases in the bacterial numbers in the total and culturable communities. Microbial biomass similarly increased. GAP fertilization also caused large shifts in both the active bacterial community structure and the active fungal community structure and additionally resulted in a decrease in the heterogeneity of the active bacterial community. Pesticide addition did not significantly affect bacterial numbers or heterogeneity, but it led to major shifts in the active soil bacterial community structure. PCR primers specific for Glomales 25S rRNA genes were used to monitor the VAM population following inoculation. Glomales were detected initially only in VAM-inoculated field sections but were subsequently detected in noninoculated field sections as the season progressed. After plowing, the level of Glomales was reduced in noninoculated field

  3. Involvement of hypothalamic AMP-activated protein kinase in leptin-induced sympathetic nerve activation.

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    Mamoru Tanida

    Full Text Available In mammals, leptin released from the white adipose tissue acts on the central nervous system to control feeding behavior, cardiovascular function, and energy metabolism. Central leptin activates sympathetic nerves that innervate the kidney, adipose tissue, and some abdominal organs in rats. AMP-activated protein kinase (AMPK is essential in the intracellular signaling pathway involving the activation of leptin receptors (ObRb. We investigated the potential of AMPKα2 in the sympathetic effects of leptin using in vivo siRNA injection to knockdown AMPKα2 in rats, to produce reduced hypothalamic AMPKα2 expression. Leptin effects on body weight, food intake, and blood FFA levels were eliminated in AMPKα2 siRNA-treated rats. Leptin-evoked enhancements of the sympathetic nerve outflows to the kidney, brown and white adipose tissues were attenuated in AMPKα2 siRNA-treated rats. To check whether AMPKα2 was specific to sympathetic changes induced by leptin, we examined the effects of injecting MT-II, a melanocortin-3 and -4 receptor agonist, on the sympathetic nerve outflows to the kidney and adipose tissue. MT-II-induced sympatho-excitation in the kidney was unchanged in AMPKα2 siRNA-treated rats. However, responses of neural activities involving adipose tissue to MT-II were attenuated in AMPKα2 siRNA-treated rats. These results suggest that hypothalamic AMPKα2 is involved not only in appetite and body weight regulation but also in the regulation of sympathetic nerve discharges to the kidney and adipose tissue. Thus, AMPK might function not only as an energy sensor, but as a key molecule in the cardiovascular, thermogenic, and lipolytic effects of leptin through the sympathetic nervous system.

  4. Involvement of hypothalamic AMP-activated protein kinase in leptin-induced sympathetic nerve activation.

    Science.gov (United States)

    Tanida, Mamoru; Yamamoto, Naoki; Shibamoto, Toshishige; Rahmouni, Kamal

    2013-01-01

    In mammals, leptin released from the white adipose tissue acts on the central nervous system to control feeding behavior, cardiovascular function, and energy metabolism. Central leptin activates sympathetic nerves that innervate the kidney, adipose tissue, and some abdominal organs in rats. AMP-activated protein kinase (AMPK) is essential in the intracellular signaling pathway involving the activation of leptin receptors (ObRb). We investigated the potential of AMPKα2 in the sympathetic effects of leptin using in vivo siRNA injection to knockdown AMPKα2 in rats, to produce reduced hypothalamic AMPKα2 expression. Leptin effects on body weight, food intake, and blood FFA levels were eliminated in AMPKα2 siRNA-treated rats. Leptin-evoked enhancements of the sympathetic nerve outflows to the kidney, brown and white adipose tissues were attenuated in AMPKα2 siRNA-treated rats. To check whether AMPKα2 was specific to sympathetic changes induced by leptin, we examined the effects of injecting MT-II, a melanocortin-3 and -4 receptor agonist, on the sympathetic nerve outflows to the kidney and adipose tissue. MT-II-induced sympatho-excitation in the kidney was unchanged in AMPKα2 siRNA-treated rats. However, responses of neural activities involving adipose tissue to MT-II were attenuated in AMPKα2 siRNA-treated rats. These results suggest that hypothalamic AMPKα2 is involved not only in appetite and body weight regulation but also in the regulation of sympathetic nerve discharges to the kidney and adipose tissue. Thus, AMPK might function not only as an energy sensor, but as a key molecule in the cardiovascular, thermogenic, and lipolytic effects of leptin through the sympathetic nervous system.

  5. Minimum inhibitory concentration of irradiated silk protein powder for bacterial activity

    Energy Technology Data Exchange (ETDEWEB)

    Tuntivisoottikul, Kunya; Bunnak, Jintana [King Mongkut' s Institute of Technology Chaokhun Taharn Ladkrabang, Faculty of Industrial Education, Dept. of Agricultural Educaiton, Bangkok (Thailand); Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2002-03-01

    The objective of this research was to study a minimum concentration level of irradiated silk protein powder, which inhibited bacterial activity. The concentration of 100 kGy irradiated silk protein powder (ISP) solution was ranged from 5 to 15% in distilled water. The activities of three types of bacteria, Escherichia coli B/r, Bacillus subtilis M3-1 and Staphylococcus aureus K, were tested by using minimum inhibition concentration method (MIC). The results indicated that the minimum concentration level that inhibited growth of E. coli B/r and S. aureus K was 5% ISP and all concentration levels studied could not inhibit the Bacilus subtilis M3-1 activity. (author)

  6. Classroom Activities to Engage Students and Promote Critical Thinking about Genetic Regulation of Bacterial Quorum Sensing

    Directory of Open Access Journals (Sweden)

    Kimberly Aebli

    2016-05-01

    Full Text Available We developed an interactive activity to mimic bacterial quorum sensing, and a classroom worksheet to promote critical thinking about genetic regulation of the lux operon. The interactive quorum sensing activity engages students and provides a direct visualization of how population density functions to influence light production in bacteria. The worksheet activity consists of practice problems that require students to apply basic knowledge of the lux operon in order to make predictions about genetic complementation experiments, and students must evaluate how genetic mutations in the lux operon affect gene expression and overall phenotype. The worksheet promotes critical thinking and problem solving skills, and emphasizes the roles of diffusible signaling molecules, regulatory proteins, and structural proteins in quorum sensing.

  7. WRKY Transcription Factors Involved in Activation of SA Biosynthesis Genes

    Directory of Open Access Journals (Sweden)

    Bol John F

    2011-05-01

    Full Text Available Abstract Background Increased defense against a variety of pathogens in plants is achieved through activation of a mechanism known as systemic acquired resistance (SAR. The broad-spectrum resistance brought about by SAR is mediated through salicylic acid (SA. An important step in SA biosynthesis in Arabidopsis is the conversion of chorismate to isochorismate through the action of isochorismate synthase, encoded by the ICS1 gene. Also AVRPPHB SUSCEPTIBLE 3 (PBS3 plays an important role in SA metabolism, as pbs3 mutants accumulate drastically reduced levels of SA-glucoside, a putative storage form of SA. Bioinformatics analysis previously performed by us identified WRKY28 and WRKY46 as possible regulators of ICS1 and PBS3. Results Expression studies with ICS1 promoter::β-glucuronidase (GUS genes in Arabidopsis thaliana protoplasts cotransfected with 35S::WRKY28 showed that over expression of WRKY28 resulted in a strong increase in GUS expression. Moreover, qRT-PCR analyses indicated that the endogenous ICS1 and PBS3 genes were highly expressed in protoplasts overexpressing WRKY28 or WRKY46, respectively. Electrophoretic mobility shift assays indentified potential WRKY28 binding sites in the ICS1 promoter, positioned -445 and -460 base pairs upstream of the transcription start site. Mutation of these sites in protoplast transactivation assays showed that these binding sites are functionally important for activation of the ICS1 promoter. Chromatin immunoprecipitation assays with haemagglutinin-epitope-tagged WRKY28 showed that the region of the ICS1 promoter containing the binding sites at -445 and -460 was highly enriched in the immunoprecipitated DNA. Conclusions The results obtained here confirm results from our multiple microarray co-expression analyses indicating that WRKY28 and WRKY46 are transcriptional activators of ICS1 and PBS3, respectively, and support this in silico screening as a powerful tool for identifying new components of stress

  8. A novel ion-beam-mutation effect application in identification of gene involved in bacterial antagonism to fungal infection of ornamental crops

    Science.gov (United States)

    Mahadtanapuk, S.; Teraarusiri, W.; Nanakorn, W.; Yu, L. D.; Thongkumkoon, P.; Anuntalabhochai, S.

    2014-05-01

    This work is on a novel application of ion beam effect on biological mutation. Bacillus licheniformis (B. licheniformis) is a common soil bacterium with an antagonistic effect on Curcuma alismatifolia Gagnep. and Chrysanthemum indicum Linn. In an attempt to control fungal diseases of local crops by utilizing B. licheniformis, we carried out gene analysis of the bacterium to understand the bacterial antagonistic mechanism. The bacterial cells were bombarded to induce mutations using nitrogen ion beam. After ion bombardment, DNA analysis revealed that the modified polymorphism fragment present in the wild type was missing in a bacterial mutant which lost the antifungal activity. The fragments conserved in the wild type but lost in the mutant bacteria was identified to code for the thioredoxin reductase (TrxR) gene. The gene analysis showed that the TrxR gene from B. licheniformis had the expression of the antagonism to fungi in a synchronous time evolution with the fungus inhibition when the bacteria were co-cultivated with the fungi. The collective results indicate the TrxR gene responsible for the antagonism of bacteria B. licheniformis to fungal infection.

  9. Hemolysis-induced lethality involves inflammasome activation by heme.

    Science.gov (United States)

    Dutra, Fabianno F; Alves, Letícia S; Rodrigues, Danielle; Fernandez, Patricia L; de Oliveira, Rosane B; Golenbock, Douglas T; Zamboni, Dario S; Bozza, Marcelo T

    2014-09-30

    The increase of extracellular heme is a hallmark of hemolysis or extensive cell damage. Heme has prooxidant, cytotoxic, and inflammatory effects, playing a central role in the pathogenesis of malaria, sepsis, and sickle cell disease. However, the mechanisms by which heme is sensed by innate immune cells contributing to these diseases are not fully characterized. We found that heme, but not porphyrins without iron, activated LPS-primed macrophages promoting the processing of IL-1β dependent on nucleotide-binding domain and leucine rich repeat containing family, pyrin domain containing 3 (NLRP3). The activation of NLRP3 by heme required spleen tyrosine kinase, NADPH oxidase-2, mitochondrial reactive oxygen species, and K(+) efflux, whereas it was independent of heme internalization, lysosomal damage, ATP release, the purinergic receptor P2X7, and cell death. Importantly, our results indicated the participation of macrophages, NLRP3 inflammasome components, and IL-1R in the lethality caused by sterile hemolysis. Thus, understanding the molecular pathways affected by heme in innate immune cells might prove useful to identify new therapeutic targets for diseases that have heme release.

  10. Proteomic analysis of growth phase-dependent expression of Legionella pneumophila proteins which involves regulation of bacterial virulence traits.

    Directory of Open Access Journals (Sweden)

    Tsuyoshi Hayashi

    Full Text Available Legionella pneumophila, which is a causative pathogen of Legionnaires' disease, expresses its virulent traits in response to growth conditions. In particular, it is known to become virulent at a post-exponential phase in vitro culture. In this study, we performed a proteomic analysis of differences in expression between the exponential phase and post-exponential phase to identify candidates associated with L. pneumophila virulence using 2-Dimentional Fluorescence Difference Gel Electrophoresis (2D-DIGE combined with Matrix-Assisted Laser Desorption/Ionization-Mass Spectrometry (MALDI-TOF-MS. Of 68 identified proteins that significantly differed in expression between the two growth phases, 64 were up-regulated at a post-exponential phase. The up-regulated proteins included enzymes related to glycolysis, ketone body biogenesis and poly-3-hydroxybutyrate (PHB biogenesis, suggesting that L. pneumophila may utilize sugars and lipids as energy sources, when amino acids become scarce. Proteins related to motility (flagella components and twitching motility-associated proteins were also up-regulated, predicting that they enhance infectivity of the bacteria in host cells under certain conditions. Furthermore, 9 up-regulated proteins of unknown function were found. Two of them were identified as novel bacterial factors associated with hemolysis of sheep red blood cells (SRBCs. Another 2 were found to be translocated into macrophages via the Icm/Dot type IV secretion apparatus as effector candidates in a reporter assay with Bordetella pertussis adenylate cyclase. The study will be helpful for virulent analysis of L. pneumophila from the viewpoint of physiological or metabolic modulation dependent on growth phase.

  11. Structural and Molecular Mechanism of CdpR Involved in Quorum-Sensing and Bacterial Virulence in Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Jingru Zhao

    2016-04-01

    Full Text Available Although quorum-sensing (QS systems are important regulators of virulence gene expression in the opportunistic human pathogen Pseudomonas aeruginosa, their detailed regulatory mechanisms have not been fully characterized. Here, we show that deletion of PA2588 resulted in increased production of pyocyanin and biofilm, as well as enhanced pathogenicity in a mouse model. To gain insights into the function of PA2588, we performed a ChIP-seq assay and identified 28 targets of PA2588, including the intergenic region between PA2588 and pqsH, which encodes the key synthase of Pseudomonas quinolone signal (PQS. Though the C-terminal domain was similar to DNA-binding regions of other AraC family members, structural studies revealed that PA2588 has a novel fold at the N-terminal region (NTR, and its C-terminal HTH (helix-turn-helix domain is also unique in DNA recognition. We also demonstrated that the adaptor protein ClpS, an essential regulator of ATP-dependent protease ClpAP, directly interacted with PA2588 before delivering CdpR to ClpAP for degradation. We named PA2588 as CdpR (ClpAP-degradation and pathogenicity Regulator. Moreover, deletion of clpP or clpS/clpA promotes bacterial survival in a mouse model of acute pneumonia infection. Taken together, this study uncovered that CdpR is an important QS regulator, which can interact with the ClpAS-P system to regulate the expression of virulence factors and pathogenicity.

  12. Multisubstrate isotope labeling and metagenomic analysis of active soil bacterial communities.

    Science.gov (United States)

    Verastegui, Y; Cheng, J; Engel, K; Kolczynski, D; Mortimer, S; Lavigne, J; Montalibet, J; Romantsov, T; Hall, M; McConkey, B J; Rose, D R; Tomashek, J J; Scott, B R; Charles, T C; Neufeld, J D

    2014-07-15

    Soil microbial diversity represents the largest global reservoir of novel microorganisms and enzymes. In this study, we coupled functional metagenomics and DNA stable-isotope probing (DNA-SIP) using multiple plant-derived carbon substrates and diverse soils to characterize active soil bacterial communities and their glycoside hydrolase genes, which have value for industrial applications. We incubated samples from three disparate Canadian soils (tundra, temperate rainforest, and agricultural) with five native carbon ((12)C) or stable-isotope-labeled ((13)C) carbohydrates (glucose, cellobiose, xylose, arabinose, and cellulose). Indicator species analysis revealed high specificity and fidelity for many uncultured and unclassified bacterial taxa in the heavy DNA for all soils and substrates. Among characterized taxa, Actinomycetales (Salinibacterium), Rhizobiales (Devosia), Rhodospirillales (Telmatospirillum), and Caulobacterales (Phenylobacterium and Asticcacaulis) were bacterial indicator species for the heavy substrates and soils tested. Both Actinomycetales and Caulobacterales (Phenylobacterium) were associated with metabolism of cellulose, and Alphaproteobacteria were associated with the metabolism of arabinose; members of the order Rhizobiales were strongly associated with the metabolism of xylose. Annotated metagenomic data suggested diverse glycoside hydrolase gene representation within the pooled heavy DNA. By screening 2,876 cloned fragments derived from the (13)C-labeled DNA isolated from soils incubated with cellulose, we demonstrate the power of combining DNA-SIP, multiple-displacement amplification (MDA), and functional metagenomics by efficiently isolating multiple clones with activity on carboxymethyl cellulose and fluorogenic proxy substrates for carbohydrate-active enzymes. Importance: The ability to identify genes based on function, instead of sequence homology, allows the discovery of genes that would not be identified through sequence alone. This

  13. High Frequency and Diversity of Antimicrobial Activities Produced by Nasal Staphylococcus Strains against Bacterial Competitors.

    Science.gov (United States)

    Janek, Daniela; Zipperer, Alexander; Kulik, Andreas; Krismer, Bernhard; Peschel, Andreas

    2016-08-01

    The human nasal microbiota is highly variable and dynamic often enclosing major pathogens such as Staphylococcus aureus. The potential roles of bacteriocins or other mechanisms allowing certain bacterial clones to prevail in this nutrient-poor habitat have hardly been studied. Of 89 nasal Staphylococcus isolates, unexpectedly, the vast majority (84%) was found to produce antimicrobial substances in particular under habitat-specific stress conditions, such as iron limitation or exposure to hydrogen peroxide. Activity spectra were generally narrow but highly variable with activities against certain nasal members of the Actinobacteria, Proteobacteria, Firmicutes, or several groups of bacteria. Staphylococcus species and many other Firmicutes were insusceptible to most of the compounds. A representative bacteriocin was identified as a nukacin-related peptide whose inactivation reduced the capacity of the producer Staphylococcus epidermidis IVK45 to limit growth of other nasal bacteria. Of note, the bacteriocin genes were found on mobile genetic elements exhibiting signs of extensive horizontal gene transfer and rearrangements. Thus, continuously evolving bacteriocins appear to govern bacterial competition in the human nose and specific bacteriocins may become important agents for eradication of notorious opportunistic pathogens from human microbiota.

  14. Gustatory-mediated avoidance of bacterial lipopolysaccharides via TRPA1 activation in Drosophila.

    Science.gov (United States)

    Soldano, Alessia; Alpizar, Yeranddy A; Boonen, Brett; Franco, Luis; López-Requena, Alejandro; Liu, Guangda; Mora, Natalia; Yaksi, Emre; Voets, Thomas; Vennekens, Rudi; Hassan, Bassem A; Talavera, Karel

    2016-06-14

    Detecting pathogens and mounting immune responses upon infection is crucial for animal health. However, these responses come at a high metabolic price (McKean and Lazzaro, 2011, Kominsky et al., 2010), and avoiding pathogens before infection may be advantageous. The bacterial endotoxins lipopolysaccharides (LPS) are important immune system infection cues (Abbas et al., 2014), but it remains unknown whether animals possess sensory mechanisms to detect them prior to infection. Here we show that Drosophila melanogaster display strong aversive responses to LPS and that gustatory neurons expressing Gr66a bitter receptors mediate avoidance of LPS in feeding and egg laying assays. We found the expression of the chemosensory cation channel dTRPA1 in these cells to be necessary and sufficient for LPS avoidance. Furthermore, LPS stimulates Drosophila neurons in a TRPA1-dependent manner and activates exogenous dTRPA1 channels in human cells. Our findings demonstrate that flies detect bacterial endotoxins via a gustatory pathway through TRPA1 activation as conserved molecular mechanism.

  15. Calcium phosphate coating containing silver shows high antibacterial activity and low cytotoxicity and inhibits bacterial adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Ando, Yoshiki, E-mail: andoy@jmmc.jp [Division of Microbiology, Department of Pathology and Microbiology, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga 849-8501 (Japan); Research Department, Japan Medical Materials Corporation, Uemura Nissei Bldg.9F 3-3-31 Miyahara, Yodogawa-ku, Osaka 532-0003 (Japan); Miyamoto, Hiroshi [Division of Microbiology, Department of Pathology and Microbiology, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga 849-8501 (Japan); Noda, Iwao; Sakurai, Nobuko [Research Department, Japan Medical Materials Corporation, Uemura Nissei Bldg.9F 3-3-31 Miyahara, Yodogawa-ku, Osaka 532-0003 (Japan); Akiyama, Tomonori [Division of Microbiology, Department of Pathology and Microbiology, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga 849-8501 (Japan); Yonekura, Yutaka; Shimazaki, Takafumi; Miyazaki, Masaki; Mawatari, Masaaki; Hotokebuchi, Takao [Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga 849-8501 (Japan)

    2010-01-01

    Surgical site infection is one of the serious complications of orthopedic implants. In order to reduce the incidence of implant-associated infections, we developed a novel coating technology of calcium phosphate (CP) containing silver (Ag), designated Ag-CP coating, using a thermal spraying technique. In this study, we evaluated the antibacterial efficacy and biological safety of this coating. In vitro antibacterial activity tests showed that the growths of Escherichia coli, Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) are completely suppressed on Ag-CP coating. In vitro bacterial adherence tests revealed that the number of adherent bacteria on the surface of this coating is significantly less (p < 0.02) than that on the surface of the CP coating. Moreover, the Ag-CP coating completely inhibits MRSA adhesion [<10 colony-forming units (CFU)] when 10{sup 2} CFU MRSA is inoculated. On the other hand, V79 Chinese hamster lung cells were found to grow on the Ag-CP coating as well as on the CP coating in a cytotoxicity test. These results indicate that the Ag-CP coating on the surface of orthopedic implants exhibits antibacterial activity and inhibits bacterial adhesion without cytotoxicity.

  16. Transcriptional activity around bacterial cell death reveals molecular biomarkers for cell viability

    Directory of Open Access Journals (Sweden)

    Schuren Frank H

    2008-12-01

    Full Text Available Abstract Background In bacteriology, the ability to grow in selective media and to form colonies on nutrient agar plates is routinely used as a retrospective criterion for the detection of living bacteria. However, the utilization of indicators for bacterial viability-such as the presence of specific transcripts or membrane integrity-would overcome bias introduced by cultivation and reduces the time span of analysis from initiation to read out. Therefore, we investigated the correlation between transcriptional activity, membrane integrity and cultivation-based viability in the Gram-positive model bacterium Bacillus subtilis. Results We present microbiological, cytological and molecular analyses of the physiological response to lethal heat stress under accurately defined conditions through systematic sampling of bacteria from a single culture exposed to gradually increasing temperatures. We identified a coherent transcriptional program including known heat shock responses as well as the rapid expression of a small number of sporulation and competence genes, the latter only known to be active in the stationary growth phase. Conclusion The observed coordinated gene expression continued even after cell death, in other words after all bacteria permanently lost their ability to reproduce. Transcription of a very limited number of genes correlated with cell viability under the applied killing regime. The transcripts of the expressed genes in living bacteria – but silent in dead bacteria-include those of essential genes encoding chaperones of the protein folding machinery and can serve as molecular biomarkers for bacterial cell viability.

  17. High Frequency and Diversity of Antimicrobial Activities Produced by Nasal Staphylococcus Strains against Bacterial Competitors.

    Directory of Open Access Journals (Sweden)

    Daniela Janek

    2016-08-01

    Full Text Available The human nasal microbiota is highly variable and dynamic often enclosing major pathogens such as Staphylococcus aureus. The potential roles of bacteriocins or other mechanisms allowing certain bacterial clones to prevail in this nutrient-poor habitat have hardly been studied. Of 89 nasal Staphylococcus isolates, unexpectedly, the vast majority (84% was found to produce antimicrobial substances in particular under habitat-specific stress conditions, such as iron limitation or exposure to hydrogen peroxide. Activity spectra were generally narrow but highly variable with activities against certain nasal members of the Actinobacteria, Proteobacteria, Firmicutes, or several groups of bacteria. Staphylococcus species and many other Firmicutes were insusceptible to most of the compounds. A representative bacteriocin was identified as a nukacin-related peptide whose inactivation reduced the capacity of the producer Staphylococcus epidermidis IVK45 to limit growth of other nasal bacteria. Of note, the bacteriocin genes were found on mobile genetic elements exhibiting signs of extensive horizontal gene transfer and rearrangements. Thus, continuously evolving bacteriocins appear to govern bacterial competition in the human nose and specific bacteriocins may become important agents for eradication of notorious opportunistic pathogens from human microbiota.

  18. Key factors for causing poplar Ice Nucleation Active bacterial canker and its control techniques

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The isolation, culture and the active determination of poplar ice nucleation active (INA) bacteria and the inoculation tests in laboratory and field were conducted, and the varieties, distribution and number of poplar INA bacteria and its pathogenicity and freezing injury property were determined. The study results showed that the INA bacteria widely spread on poplar in Northeast China and caused the frozen injury for poplar under the frost condition in Spring or Autumn, which was the key factor to induce INA bacterial canker. Through evaluation and investigation of different poplar varieties and inoculation tests, fine disease-resistant varieties and strains of poplar suitable for Northeast China were selected. Further tests for strong seedling showed that burying cuttings in sand and covering with plastic film could effectively avoid the frostbite, frozen and drought damage, reduce INA bacteria infection, and promote poplar growth. INA bacterial canker was detected early by highly specialized antiserums of INA bacteria and the agglutinated test of ring-shaped boundary surface. The inducers such as streptomycin, phenylmercuric acetae, salicylic acid and heat-killed bacteria to immerse cuttings, have obvious induced disease-resistant effect. Before poplar sprouted in early spring, through spraying the solution of frostbite agent, the control effect also was obvious.

  19. Nitrate reducing bacterial activity in concrete cells of nuclear waste disposal

    Science.gov (United States)

    Alquier, M.; Kassim, C.; Bertron, A.; Rafrafi, Y.; Sablayrolles, C.; Albrecht, A.; Erable, B.

    2013-07-01

    Leaching experiments of solid matrices (bitumen and cement pastes) have been first implemented to define the physicochemical conditions that microorganisms are likely to meet at the bitumen-concrete interface (see the paper of Bertron et al.). Of course, as might be suspected, the cement matrix imposes highly alkaline pH conditions (10 bacterial strains led us to select Halomonas desiderata as a model bacterium capable of catalyzing the reaction of nitrate reduction in these extreme conditions of pH. The denitrifying activity of Halomonas desiderata was quantified in batch bioreactor in the presence of solid matrices and / or leachate from bitumen and cement matrices. Denitrification was relatively fast in the presence of cement matrix (<100 hours) and 2 to 3 times slower in the presence of bituminous matrix. Overall, the presence of solid cement promoted the kinetics of denitrification. The observation of solid surfaces at the end of the experiment revealed the presence of a biofilm of Halomonas desiderata on the cement paste surface. These attached bacteria showed a denitrifying activity comparable to planktonic bacterial culture. On the other side, no colonization of bitumen could be highlighted as either by SEM or epifluorescence microscopy. Now, we are currently developing a continuous experimental bioreactor which should allow us a more rational understanding of the bitumen-cement-microbe interactions.

  20. Nitrate reducing bacterial activity in concrete cells of nuclear waste disposal

    Directory of Open Access Journals (Sweden)

    Albrecht A.

    2013-07-01

    Full Text Available Leaching experiments of solid matrices (bitumen and cement pastes have been first implemented to define the physicochemical conditions that microorganisms are likely to meet at the bitumen-concrete interface (see the paper of Bertron et al.. Of course, as might be suspected, the cement matrix imposes highly alkaline pH conditions (10 bacterial strains led us to select Halomonas desiderata as a model bacterium capable of catalyzing the reaction of nitrate reduction in these extreme conditions of pH. The denitrifying activity of Halomonas desiderata was quantified in batch bioreactor in the presence of solid matrices and / or leachate from bitumen and cement matrices. Denitrification was relatively fast in the presence of cement matrix (<100 hours and 2 to 3 times slower in the presence of bituminous matrix. Overall, the presence of solid cement promoted the kinetics of denitrification. The observation of solid surfaces at the end of the experiment revealed the presence of a biofilm of Halomonas desiderata on the cement paste surface. These attached bacteria showed a denitrifying activity comparable to planktonic bacterial culture. On the other side, no colonization of bitumen could be highlighted as either by SEM or epifluorescence microscopy. Now, we are currently developing a continuous experimental bioreactor which should allow us a more rational understanding of the bitumen-cement-microbe interactions.

  1. Gram-positive bacterial cell envelopes: The impact on the activity of antimicrobial peptides.

    Science.gov (United States)

    Malanovic, Nermina; Lohner, Karl

    2016-05-01

    A number of cationic antimicrobial peptides, effectors of innate immunity, are supposed to act at the cytoplasmic membrane leading to permeabilization and eventually membrane disruption. Thereby, interaction of antimicrobial peptides with anionic membrane phospholipids is considered to be a key factor in killing of bacteria. Recently, evidence was provided that killing takes place only when bacterial cell membranes are completely saturated with peptides. This adds to an ongoing debate, which role cell wall components such as peptidoglycan, lipoteichoic acid and lipopolysaccharide may play in the killing event, i.e. if they rather entrap or facilitate antimicrobial peptides access to the cytoplasmic membrane. Therefore, in this review we focused on the impact of Gram-positive cell wall components for the mode of action and activity of antimicrobial peptides as well as in innate immunity. This led us to conclude that interaction of antimicrobial peptides with peptidoglycan may not contribute to a reduction of their antimicrobial activity, whereas interaction with anionic lipoteichoic acids may reduce the local concentration of antimicrobial peptides on the cytoplasmic membrane necessary for sufficient destabilization of the membranes and bacterial killing. Further affinity studies of antimicrobial peptides toward the different cell wall as well as membrane components will be needed to address this problem on a quantitative level. This article is part of a Special Issue entitled: Antimicrobial peptides edited by Karl Lohner and Kai Hilpert.

  2. FAMILY INVOLVEMENT ACTIVITIES AT PRESCHOOL EDUCATIONAL INSTITUTIONS: CASE OF DENIZLI PROVINCE

    Directory of Open Access Journals (Sweden)

    Hülya GÜLAY OGELMAN

    2014-06-01

    Full Text Available The purpose of this study is to investigate family involvement activities at preschool educational institutions in province of Denizli. 25 female teachers working at preschool educational institutions under Ministry of National Education in city centre of Denizli were included in the study. The results revealed that while a great majority of 32 family involvement activities included in the questionnaire (parents' corner, posters, education board, communication board, brochures, booklets, periodicals-newspapers, newsletters, correspondences, photographs, phone/ internet calls, video/tape records, conferences, home visits, article box, request box, parents' libraries, family involvement to non-classroom activities, diaries, family involvement into management and decision-making process, group meeting weren’t performed, 11 activities were implemented. While 4 of 11 activities were performed by all teachers, there were teachers who didn't perform 7 family involvement activities (parents' meetings, individual interview, development reports, collective files, involvement to classroom activities, invitation of parents to the school in special occasions, activities held at home. Considering the reasons why twenty two family involvement activities were not performed; lack of space, time and possibilities was the most frequent reason. Home visits took place on the top among family involvement activities the teachers had difficulties at most. The individual interviews were among activities conducted by the teachers in the easiest/ comfortable way.

  3. Serum lipoproteins attenuate macrophage activation and Toll-Like Receptor stimulation by bacterial lipoproteins

    Directory of Open Access Journals (Sweden)

    James Richard W

    2010-09-01

    Full Text Available Abstract Background Chlamydia trachomatis was previously shown to express a lipoprotein, the macrophage infectivity potentiator (Mip, exposed at the bacterial surface, and able to stimulate human primary monocytes/macrophages through Toll Like Receptor (TLR2/TLR1/TLR6, and CD14. In PMA-differentiated THP-1 cells the proinflammatory activity of Mip was significantly higher in the absence than in the presence of serum. The present study aims to investigate the ability of different serum factors to attenuate Mip proinflammatory activity in PMA-differentiated THP-1 cells and in primary human differentiated macrophages. The study was also extend to another lipoprotein, the Borrelia burgdorferi outer surface protein (OspA. The proinflammatory activity was studied through Tumor Necrosis Factor alpha (TNF-α and Interleukin (IL-8 release. Finally, TLR1/2 human embryonic kidney-293 (HEK-293 transfected cells were used to test the ability of the serum factors to inhibit Mip and OspA proinflammatory activity. Results In the absence of any serum and in the presence of 10% delipidated FBS, production of Mip-induced TNF-α and IL-8 in PMA-differentiated THP-1 cells were similar whereas they were significantly decreased in the presence of 10% FBS suggesting an inhibiting role of lipids present in FBS. In the presence of 10% human serum, the concentrations of TNF-α and IL-8 were 2 to 5 times lower than in the presence of 10% FBS suggesting the presence of more potent inhibitor(s in human serum than in FBS. Similar results were obtained in primary human differentiated macrophages. Different lipid components of human serum were then tested (total lipoproteins, HDL, LDL, VLDL, triglyceride emulsion, apolipoprotein (apoA-I, B, E2, and E3. The most efficient inhibitors were LDL, VLDL, and apoB that reduced the mean concentration of TNF-α release in Mip-induced macrophages to 24, 20, and 2%, respectively (p Conclusions These results demonstrated the ability of

  4. The antimicrobial activity of thyme essential oil against multidrug resistant clinical bacterial strains.

    Science.gov (United States)

    Sienkiewicz, Monika; Łysakowska, Monika; Denys, Paweł; Kowalczyk, Edward

    2012-04-01

    The aim of this work was to investigate the antimicrobial activity of thyme essential oil against clinical multidrug resistant strains of Staphylococcus, Enterococcus, Escherichia, and Pseudomonas genus. The antibacterial activity of oil was tested against standard strains of bacteria and 120 clinical strains isolated from patients with infections of the oral cavity, abdominal cavity, respiratory and genitourinary tracts, skin, and from the hospital environment. Agar diffusion was used to determine the microbial growth inhibition of bacterial growth at various concentrations of oil from Thymus vulgaris. Susceptibility testing to antibiotics was carried out using disk diffusion. Thyme essential oil strongly inhibited the growth of the clinical strains of bacteria tested. The use of phytopharmaceuticals based on an investigated essential oil from thyme in the prevention and treatment of various human infections may be reasonable.

  5. ANTI-TUMOR ACTIVITY OF BACTERIAL LECTIN AND 5-METHYLURACIL ADDUCT

    Directory of Open Access Journals (Sweden)

    Elena Welchinska

    2014-07-01

    Full Text Available The synthesis was performed using 5-methyluracil mono-and bis-derivatives with the halogen-containing pharmacophore groups in the composition of molecules; their physiochemical and biological properties were studied. These reactions are a typical example of substitution reactions on heteroatom N(1 of uracil molecule using as the second component the reaction of halothane—the known inhaled anesthetic.  The reactions were carried out in a solvent system: benzene-dimethyl formamide and diethyl ether, under conditions of phase transfer catalysis DB-18-crown-6-complex (alkaline medium, by heating from 2 to 11 hours, followed by purification, and drying of the resulting products.  The structure of the synthesized compounds was confirmed by elemental analysis, IR and 1HNMR spectra.  The purity was controlled by the methods of thin-layer and gas-liquid chromatography. Chromatography, IR and 1HNMR spectra of the final products were identified in comparison with the chromatograms, IR and 1HNMR spectra of the initial compounds. Variation of the reaction conditions and changes in methods of synthesis enabled to receive the synthesized compounds of high purity and to increase their practical output up to 43-80%.  Molecular complex of Bacterial lectin and 5-methyluracil bis-derivative was obtained.  The toxicity and anti-tumor activity of some of the synthesized compounds were investigated. We have found that the new molecular complex of Bacterial lectin and 5-methyluracil bis-derivative has high anti-tumor activity in Limphosarcoma Plissa—62.8% (activity criterion >50%, which allows us to consider the synthesized compound as a physiologically active compound with the prospect for further study as a potential vehicle for anti-tumoral treatment in patients. 

  6. Predicting involvement in prison gang activity: street gang membership, social and psychological factors.

    Science.gov (United States)

    Wood, Jane L; Alleyne, Emma; Mozova, Katarina; James, Mark

    2014-06-01

    The aim of this study was to examine whether street gang membership, psychological factors, and social factors such as preprison experiences could predict young offenders' involvement in prison gang activity. Data were collected via individual interviews with 188 young offenders held in a Young Offenders Institution in the United Kingdom. Results showed that psychological factors such as the value individuals attached to social status, a social dominance orientation, and antiauthority attitudes were important in predicting young offenders' involvement in prison gang activity. Further important predictors included preimprisonment events such as levels of threat, levels of individual delinquency, and levels of involvement in group crime. Longer current sentences also predicted involvement in prison gang activity. However, street gang membership was not an important predictor of involvement in prison gang activity. These findings have implications for identifying prisoners involved in prison gang activity and for considering the role of psychological factors and group processes in gang research.

  7. Effect of long-term industrial waste effluent pollution on soil enzyme activities and bacterial community composition.

    Science.gov (United States)

    Subrahmanyam, Gangavarapu; Shen, Ju-Pei; Liu, Yu-Rong; Archana, Gattupalli; Zhang, Li-Mei

    2016-02-01

    Although numerous studies have addressed the influence of exogenous pollutants on microorganisms, the effect of long-term industrial waste effluent (IWE) pollution on the activity and diversity of soil bacteria was still unclear. Three soil samples characterized as uncontaminated (R1), moderately contaminated (R2), and highly contaminated (R3) receiving mixed organic and heavy metal pollutants for more than 20 years through IWE were collected along the Mahi River basin, Gujarat, western India. Basal soil respiration and in situ enzyme activities indicated an apparent deleterious effect of IWE on microbial activity and soil function. Community composition profiling of soil bacteria using 16S rRNA gene amplification and denaturing gradient gel electrophoresis (DGGE) method indicated an apparent bacterial community shift in the IWE-affected soils. Cloning and sequencing of DGGE bands revealed that the dominated bacterial phyla in polluted soil were affiliated with Firmicutes, Acidobacteria, and Actinobacteria, indicating that these bacterial phyla may have a high tolerance to pollutants. We suggested that specific bacterial phyla along with soil enzyme activities could be used as relevant biological indicators for long-term pollution assessment on soil quality. Graphical Abstract Bacterial community profiling and soil enzyme activities in long-term industrial waste effluent polluted soils.

  8. Desulfurization activity and reusability of magnetite nanoparticle-coated Rhodococcus erythropolis FMF and R. erythropolis IGTS8 bacterial cells.

    Science.gov (United States)

    Bardania, Hassan; Raheb, Jamshid; Mohammad-Beigi, Hossein; Rasekh, Behnam; Arpanaei, Ayyoob

    2013-01-01

    The application of Fe3 O4 nanoparticles to the separation of desulfurizing bacterial cells and their influence on the desulfurization activity and reusability of the two bacterial strains Rhodococcus erythropolis FMF and R. erythropolis IGTS8 were investigated. Magnetite nanoparticles were synthesized via the reverse coprecipitation method. Transmission electron microscopy (TEM) images showed that the magnetite nanoparticles had sizes of 5.35 ± 1.13 (F1 nanoparticles) and 8.74 ± 1.18 nm (F2 nanoparticles) when glycine was added during the synthesis of nanoparticles and when it was absent from the reaction mixture, respectively. Glycine was added after the synthesis of both F1 and F2 nanoparticles to stabilize the nanoparticle dispersion. TEM images of cells treated with magnetite nanoparticles indicated that F1 nanoparticles were immobilized on the surface of bacterial cells more evenly than the F2 nanoparticles. Desulfurization activities of the F1 magnetite nanoparticle-coated R. erythropolis FMF and R. erythropolis IGTS8 cells (with sulfur-removal percentage values of 70 ± 4 and 73 ± 3, respectively), as examined with the spectrophotometric Gibbs assay (based on dibenzothiophene degradation and sulfur-removal percentage), were not significantly different from those for the free bacterial cells (67 ± 3 and 69 ± 4, respectively). These results indicate that magnetite nanoparticles cannot affect the desulfurization activity of cells examined in this work. Isolation of bacterial cells from the suspension using a magnet and evaluation of desulfurization activity of separated cells showed that Fe3 O4 nanoparticles can provide a high-efficiency recovery of bacterial cells from a suspension, with the reused magnetite nanoparticle-coated bacterial cells being able to maintain their desulfurization activity efficiently. © 2013 International Union of Biochemistry and Molecular Biology, Inc.

  9. Community dynamics and glycoside hydrolase activities of thermophilic bacterial consortia adapted to switchgrass

    Energy Technology Data Exchange (ETDEWEB)

    Gladden, J.M.; Allgaier, M.; Miller, C.S.; Hazen, T.C.; VanderGheynst, J.S.; Hugenholtz, P.; Simmons, B.A.; Singer, S.W.

    2011-05-01

    Industrial-scale biofuel production requires robust enzymatic cocktails to produce fermentable sugars from lignocellulosic biomass. Thermophilic bacterial consortia are a potential source of cellulases and hemicellulases adapted to harsher reaction conditions than commercial fungal enzymes. Compost-derived microbial consortia were adapted to switchgrass at 60 C to develop thermophilic biomass-degrading consortia for detailed studies. Microbial community analysis using small-subunit rRNA gene amplicon pyrosequencing and short-read metagenomic sequencing demonstrated that thermophilic adaptation to switchgrass resulted in low-diversity bacterial consortia with a high abundance of bacteria related to thermophilic paenibacilli, Rhodothermus marinus, and Thermus thermophilus. At lower abundance, thermophilic Chloroflexi and an uncultivated lineage of the Gemmatimonadetes phylum were observed. Supernatants isolated from these consortia had high levels of xylanase and endoglucanase activities. Compared to commercial enzyme preparations, the endoglucanase enzymes had a higher thermotolerance and were more stable in the presence of 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]), an ionic liquid used for biomass pretreatment. The supernatants were used to saccharify [C2mim][OAc]-pretreated switchgrass at elevated temperatures (up to 80 C), demonstrating that these consortia are an excellent source of enzymes for the development of enzymatic cocktails tailored to more extreme reaction conditions.

  10. Nε-lysine acetylation of a bacterial transcription factor inhibits Its DNA-binding activity.

    Directory of Open Access Journals (Sweden)

    Sandy Thao

    Full Text Available Evidence suggesting that eukaryotes and archaea use reversible N(ε-lysine (N(ε-Lys acetylation to modulate gene expression has been reported, but evidence for bacterial use of N(ε-Lys acetylation for this purpose is lacking. Here, we report data in support of the notion that bacteria can control gene expression by modulating the acetylation state of transcription factors (TFs. We screened the E. coli proteome for substrates of the bacterial Gcn5-like protein acetyltransferase (Pat. Pat acetylated four TFs, including the RcsB global regulatory protein, which controls cell division, and capsule and flagellum biosynthesis in many bacteria. Pat acetylated residue Lys180 of RcsB, and the NAD(+-dependent Sir2 (sirtuin-like protein deacetylase (CobB deacetylated acetylated RcsB (RcsB(Ac, demonstrating that N(ε-Lys acetylation of RcsB is reversible. Analysis of RcsB(Ac and variant RcsB proteins carrying substitutions at Lys180 provided biochemical and physiological evidence implicating Lys180 as a critical residue for RcsB DNA-binding activity. These findings further the likelihood that reversible N(ε-Lys acetylation of transcription factors is a mode of regulation of gene expression used by all cells.

  11. Endogenous bacterial toxins are required for the injurious action of platelet-activating factor in rats.

    Science.gov (United States)

    Sun, X M; MacKendrick, W; Tien, J; Huang, W; Caplan, M S; Hsueh, W

    1995-07-01

    Platelet-activating factor (PAF), an endogenous mediator for experimental sepsis, has been shown to induce shock and intestinal necrosis in vivo. However, it is unclear whether PAF exerts its injurious effects on the intestinal tissue directly or via synergism with other endogenous products. The aim of this study was to examine the role of endogenous bacterial products, such as endotoxin, in PAF-induced intestinal injury. PAF (3 micrograms/kg) was injected intravenously into normally colonized rats, germfree rats, and normal rats pretreated with a combination of antibiotics, and the systemic response and intestinal injury were assessed. PAF did not cause prolonged shock, leukopenia, hemoconcentration, and bowel necrosis in germfree rats. When germfree rats were primed with a low dose (0.5 mg/kg) of endotoxin, the protection was lost. Combined treatment of the normally colonized rats with neomycin, polymyxin B, and metronidazole for 7 days largely protected the animal from PAF-induced shock and intestinal necrosis. PAF does not directly induce prolonged hypotension, hemoconcentration, persistent leukopenia, and gross intestinal necrosis but causes these changes via a synergism with endogenous bacterial toxins, presumably from the gut flora.

  12. The impact of zinc oxide nanoparticles on the bacterial microbiome of activated sludge systems

    Science.gov (United States)

    Meli, K.; Kamika, I.; Keshri, J.; Momba, M. N. B.

    2016-12-01

    The expected growth in nanomaterial applications could result in increased amounts of nanoparticles entering municipal sewer systems, eventually ending up in wastewater treatment plants and therefore negatively affecting microbial populations and biological nutrient removal. The aim of this study was to ascertain the impact of zinc oxide nanoparticles (nZnO) on the bacterial microbiome of an activated sludge system. A metagenomic approach combined with the latest generation Illumina MiSeq platform and RDP pipeline tools were used to identify and classify the bacterial microbiome of the sludge. Results revealed a drastic decrease in the number of operational taxonomic units (OTUs) from 27 737 recovered in the nZnO-free sample to 23 743, 17 733, and 13 324 OTUs in wastewater samples exposed to various concentrations of nZnO (5, 10 and 100 mg/L nZnO, respectively). These represented 12 phyla, 21 classes, 30 orders, 54 families and 51 genera, completely identified at each taxonomic level in the control samples; 7-15-25-28-20 for wastewater samples exposed to 5 mg/L nZnO; 9-15-24-31-23 for those exposed to 10 mg/L and 7-11-19-26-17 for those exposed 100 mg/L nZnO. A large number of sequences could not be assigned to specific taxa, suggesting a possibility of novel species to be discovered.

  13. Particle-associated extracellular enzyme activity and bacterial community composition across the Canadian Arctic Ocean.

    Science.gov (United States)

    Kellogg, Colleen T E; Deming, Jody W

    2014-08-01

    Microbial enzymatic hydrolysis of marine-derived particulate organic carbon (POC) can be a dominant mechanism for attenuating carbon flux in cold Arctic waters during spring and summer. Whether this mechanism depends on composition of associated microbial communities and extends into other seasons is not known. Bacterial community composition (BCC) and extracellular enzyme activity (EEA, for leucine aminopeptidases, glucosidases and chitobiases) were measured on small suspended particles and potentially sinking aggregates collected during fall from waters of the biologically productive North Water and river-impacted Beaufort Sea. Although other environmental variables appeared influential, both BCC and EEA varied along a marine productivity gradient in the two regions. Aggregates harbored the most distinctive bacterial communities, with a small number of taxa driving differences between particle-size classes (1.0-60 and > 60 μm) and free-living bacteria (0.2-1.0 μm). Significant relationships between patterns in particle-associated BCC and EEA suggest strong links between these two variables. Calculations indicated that up to 80% of POC in the euphotic zone of the North Water, and 20% in the Beaufort Sea, may be hydrolyzed enzymatically, underscoring the importance of this mechanism in attenuating carbon fluxes in Arctic waters even as winter approaches.

  14. Actividad sialidasa en mujeres con vaginosis bacteriana Sialidase activity in women with bacterial vaginosis

    Directory of Open Access Journals (Sweden)

    Adriana M. Ombrella

    2006-04-01

    Full Text Available La vaginosis bacteriana (VB es un síndrome caracterizado por el sobrecrecimiento bacteriano de flora endógena Gram negativa, que desplaza a la flora lactobacilar normal. Dentro de las enzimas bacterianas, las sialidasas han sido consideradas factores de virulencia de muchos microorganismos patógenos que colonizan las distintas mucosas. Su presencia en fluidos vaginales puede estar correlacionada con VB. El propósito de este estudio fue comprobar la actividad de dicha enzima en mujeres con este síndrome y sin evidencia clínica de infección genital. Se estudiaron 112 mujeres (51 fueron pacientes con VB y 61 mujeres con flora colonizante habitual. Para la cuantificación de la actividad sialidasa se empleó la técnica basada en la hidrólisis enzimática de un derivado ácido del ácido metoxifenil acetil murámico. En la población estudiada se encontró que ambos grupos mostraron valores comprendidos entre 0.5 a 5.1 nmoles de metoxifenol, mientras que 11 de 52 pacientes con VB (21.17%, registraron valores superiores a 5.1 nmoles. La presencia de actividad sialidasa solamente no es índice de VB, excepto para valores mayores de 5.5 nmoles de metoxifenol, producidos en la reacción enzimática.Bacterial vaginosis (VB is a syndrome characterized by overgrowth of endogenous Gram negative bacterial flora and the lack of the normal flora. Within bacterial enzymes, sialidases have been considered a virulence factor of many pathogenic microorganisms colonizing the different mucous membranes. Their presence in vaginal discharges can be correlated with VB. The aim of this study was to detect the activity of this enzyme in women with this syndrome and without clinical evidence of genital infection. Out of a total 112 women studied, 51 were patients with VB and the other 61 women presented normal vaginal flora. For the quantification of enzyme activity, the technique based on the enzymatic hydrolysis of a derivative acid of the acetyl metoxifenil

  15. Bacterial AvrRpt2-Like Cysteine Proteases Block Activation of the Arabidopsis Mitogen-Activated Protein Kinases, MPK4 and MPK111[OPEN

    Science.gov (United States)

    Eschen-Lippold, Lennart; Jiang, Xiyuan; Elmore, James Mitch; Mackey, David; Shan, Libo

    2016-01-01

    To establish infection, pathogens deliver effectors into host cells to target immune signaling components, including elements of mitogen-activated protein kinase (MPK) cascades. The virulence function of AvrRpt2, one of the first identified Pseudomonas syringae effectors, involves cleavage of the plant defense regulator, RPM1-INTERACTING PROTEIN4 (RIN4), and interference with plant auxin signaling. We show now that AvrRpt2 specifically suppresses the flagellin-induced phosphorylation of Arabidopsis (Arabidopsis thaliana) MPK4 and MPK11 but not MPK3 or MPK6. This inhibition requires the proteolytic activity of AvrRpt2, is associated with reduced expression of some plant defense genes, and correlates with enhanced pathogen infection in AvrRpt2-expressing transgenic plants. Diverse AvrRpt2-like homologs can be found in some phytopathogens, plant-associated and soil bacteria. Employing these putative bacterial AvrRpt2 homologs and inactive AvrRpt2 variants, we can uncouple the inhibition of MPK4/MPK11 activation from the cleavage of RIN4 and related members from the so-called nitrate-induced family as well as from auxin signaling. Thus, this selective suppression of specific mitogen-activated protein kinases is independent of the previously known AvrRpt2 targets and potentially represents a novel virulence function of AvrRpt2. PMID:27208280

  16. Bacterial Enzymatic Activity and Bioavailability of Heavy Metals in Sediments from Boa Viagem Beach (Guanabara Bay

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    Mirian Crapez

    2003-01-01

    Full Text Available This study focuses on the quality of the organic matter that reaches the sediment from Boa Viagem Beach and through the evaluation of the total bacterial count, the electron transport system activity (ETSA, the esterase activity (EST, as well as the protein and the organic matter contents. Seasonal variations of organic matter, protein content and the number of bacteria were particularly notable in the summer. ETSA reached a maximum of 7.48 µl O 2 h-1 g-1 in the summer. EST activity presented a different pattern once it reached a maximum of 0.17 µg fluorescein h-1 g-1 in the winter. The temporal variation of ETSA and EST activity indicated that biopolymers predominated in the winter, and oligomers or monomers predominated in the summer. These results suggest that organic carbon turnover is more likely to be controlled by organic matter quality. The heavy metals concentrations, especially for Cu, Zn, Ni and Cr, indicated absence of the inhibition of dehydrogenase activity, and they are not bioavailable in the EC 50 values

  17. Seasonal effect and anthropogenic impact on the composition of the active bacterial community in Mediterranean orchard soil.

    Science.gov (United States)

    Frenk, Sammy; Dag, Arnon; Yermiyahu, Uri; Zipori, Isaac; Hadar, Yitzhak; Minz, Dror

    2015-09-01

    Several anthropogenic interventions, common in agriculture, may influence active bacterial communities in soil without affecting their total composition. Therefore, the composition of an active bacterial community in soil may reflect its relation to biogeochemical processes. This issue was addressed during two consecutive years in olive-orchard soil, irrigated with treated wastewater (TWW) in a Mediterranean climate, by following the active (rRNA) and total (rRNA gene) bacterial community in the soil. Although TWW irrigation did not affect the composition of the total soil bacterial community, it had an effect on the active fraction of the community. These results, based on 16S rRNA data, indicate that the organic matter and minerals in TWW were not directly utilized for the rapid proliferation of specific taxonomic groups. Activity levels, manifested by variance in the relative abundance of the active and total communities of selected operational taxonomic units, revealed annual and seasonal fluctuations and fluctuations dependent on the type of irrigation. The potential activity (nitrification rates) and community composition of ammonia-oxidizing bacteria were affected by TWW irrigation, and this group of bacteria was therefore further explored. It was concluded that irrigation with TWW had little effect on "who is there", i.e. which bacteria were present, but influenced "who is active", with a distinct effect on bacteria associated with the biochemical cycling of nitrogen.

  18. Identification of the bacterial protein FtsX as a unique target of chemokine-mediated antimicrobial activity against Bacillus anthracis

    Science.gov (United States)

    Crawford, Matthew A.; Lowe, David E.; Fisher, Debra J.; Stibitz, Scott; Plaut, Roger D.; Beaber, John W.; Zemansky, Jason; Mehrad, Borna; Glomski, Ian J.; Strieter, Robert M.; Hughes, Molly A.

    2011-01-01

    Chemokines are a family of chemotactic cytokines that function in host defense by orchestrating cellular movement during infection. In addition to this function, many chemokines have also been found to mediate the direct killing of a range of pathogenic microorganisms through an as-yet-undefined mechanism. As an understanding of the molecular mechanism and microbial targets of chemokine-mediated antimicrobial activity is likely to lead to the identification of unique, broad-spectrum therapeutic targets for effectively treating infection, we sought to investigate the mechanism by which the chemokine CXCL10 mediates bactericidal activity against the Gram-positive bacterium Bacillus anthracis, the causative agent of anthrax. Here, we report that disruption of the gene ftsX, which encodes the transmembrane domain of a putative ATP-binding cassette transporter, affords resistance to CXCL10-mediated antimicrobial effects against vegetative B. anthracis bacilli. Furthermore, we demonstrate that in the absence of FtsX, CXCL10 is unable to localize to its presumed site of action at the bacterial cell membrane, suggesting that chemokines interact with specific, identifiable bacterial components to mediate direct microbial killing. These findings provide unique insight into the mechanism of CXCL10-mediated bactericidal activity and establish, to our knowledge, the first description of a bacterial component critically involved in the ability of host chemokines to target and kill a bacterial pathogen. These observations also support the notion of chemokine-mediated antimicrobial activity as an important foundation for the development of innovative therapeutic strategies for treating infections caused by pathogenic, potentially multidrug-resistant microorganisms. PMID:21949405

  19. Identification of the bacterial protein FtsX as a unique target of chemokine-mediated antimicrobial activity against Bacillus anthracis.

    Science.gov (United States)

    Crawford, Matthew A; Lowe, David E; Fisher, Debra J; Stibitz, Scott; Plaut, Roger D; Beaber, John W; Zemansky, Jason; Mehrad, Borna; Glomski, Ian J; Strieter, Robert M; Hughes, Molly A

    2011-10-11

    Chemokines are a family of chemotactic cytokines that function in host defense by orchestrating cellular movement during infection. In addition to this function, many chemokines have also been found to mediate the direct killing of a range of pathogenic microorganisms through an as-yet-undefined mechanism. As an understanding of the molecular mechanism and microbial targets of chemokine-mediated antimicrobial activity is likely to lead to the identification of unique, broad-spectrum therapeutic targets for effectively treating infection, we sought to investigate the mechanism by which the chemokine CXCL10 mediates bactericidal activity against the Gram-positive bacterium Bacillus anthracis, the causative agent of anthrax. Here, we report that disruption of the gene ftsX, which encodes the transmembrane domain of a putative ATP-binding cassette transporter, affords resistance to CXCL10-mediated antimicrobial effects against vegetative B. anthracis bacilli. Furthermore, we demonstrate that in the absence of FtsX, CXCL10 is unable to localize to its presumed site of action at the bacterial cell membrane, suggesting that chemokines interact with specific, identifiable bacterial components to mediate direct microbial killing. These findings provide unique insight into the mechanism of CXCL10-mediated bactericidal activity and establish, to our knowledge, the first description of a bacterial component critically involved in the ability of host chemokines to target and kill a bacterial pathogen. These observations also support the notion of chemokine-mediated antimicrobial activity as an important foundation for the development of innovative therapeutic strategies for treating infections caused by pathogenic, potentially multidrug-resistant microorganisms.

  20. Seasonal Variation in Soil Microbial Biomass, Bacterial Community Composition and Extracellular Enzyme Activity in Relation to Soil Respiration in a Northern Great Plains Grassland

    Science.gov (United States)

    Wilton, E.; Flanagan, L. B.

    2014-12-01

    Soil respiration rate is affected by seasonal changes in temperature and moisture, but is this a direct effect on soil metabolism or an indirect effect caused by changes in microbial biomass, bacterial community composition and substrate availability? In order to address this question, we compared continuous measurements of soil and plant CO2 exchange made with an automatic chamber system to analyses conducted on replicate soil samples collected on four dates during June-August. Microbial biomass was estimated from substrate-induced respiration rate, bacterial community composition was determined by 16S rRNA amplicon pyrosequencing, and β-1,4-N-acetylglucosaminidase (NAGase) and phenol oxidase enzyme activities were assayed fluorometrically or by absorbance measurements, respectively. Soil microbial biomass declined from June to August in strong correlation with a progressive decline in soil moisture during this time period. Soil bacterial species richness and alpha diversity showed no significant seasonal change. However, bacterial community composition showed a progressive shift over time as measured by Bray-Curtis dissimilarity. In particular, the change in community composition was associated with increasing relative abundance in the alpha and delta classes, and declining abundance of the beta and gamma classes of the Proteobacteria phylum during June-August. NAGase showed a progressive seasonal decline in potential activity that was correlated with microbial biomass and seasonal changes in soil moisture. In contrast, phenol oxidase showed highest potential activity in mid-July near the time of peak soil respiration and ecosystem photosynthesis, which may represent a time of high input of carbon exudates into the soil from plant roots. This input of exudates may stimulate the activity of phenol oxidase, a lignolytic enzyme involved in the breakdown of soil organic matter. These analyses indicated that seasonal change in soil respiration is a complex

  1. Major involvement of bacterial components in rheumatoid arthritis and its accompanying oxidative stress, systemic inflammation and hypercoagulability.

    Science.gov (United States)

    Pretorius, Etheresia; Akeredolu, Oore-Ofe; Soma, Prashilla; Kell, Douglas B

    2017-02-01

    We review the evidence that infectious agents, including those that become dormant within the host, have a major role to play in much of the etiology of rheumatoid arthritis and the inflammation that is its hallmark. This occurs in particular because they can produce cross-reactive (auto-)antigens, as well as potent inflammagens such as lipopolysaccharide that can themselves catalyze further inflammagenesis, including via β-amyloid formation. A series of observables coexist in many chronic, inflammatory diseases as well as rheumatoid arthritis. They include iron dysregulation, hypercoagulability, anomalous morphologies of host erythrocytes, and microparticle formation. Iron dysregulation may be responsible for the periodic regrowth and resuscitation of the dormant bacteria, with concomitant inflammagen production. The present systems biology analysis benefits from the philosophical idea of "coherence," that reflects the principle that if a series of ostensibly unrelated findings are brought together into a self-consistent narrative, that narrative is thereby strengthened. As such, we provide a coherent and testable narrative for the major involvement of (often dormant) bacteria in rheumatoid arthritis.

  2. Identification, structural, and biochemical characterization of a group of large Csn2 proteins involved in CRISPR-mediated bacterial immunity.

    Science.gov (United States)

    Lee, Kwang-Hoon; Lee, Seong-Gyu; Eun Lee, Kyung; Jeon, Hyesung; Robinson, Howard; Oh, Byung-Ha

    2012-11-01

    Many prokaryotic organisms acquire immunity against foreign genetic material by incorporating a short segment of foreign DNA called spacer into chromosomal loci, termed clustered regularly interspaced short palindromic repeats (CRISPRs). The encoded RNAs are processed into small fragments that guide the silencing of the invading genetic elements. The CRISPR-associated (Cas) proteins are the main executioners of these processes. Herein, we report the crystal structure of Stu0660 of Streptococcus thermophilus, a Cas protein involved in the acquisition of new spacers. By homotetramerization, Stu0660 forms a central channel which is decorated with basic amino acids and binds linear double-stranded DNA (dsDNA), but not circular dsDNA. Despite undetectably low sequence similarity, two N-terminal domains of Stu0660 are similar to the entire structure of an Enterococcus faecalis Csn2 protein, which also forms a homotetramer and binds dsDNA. Thus, this work identifies a previously unknown group of Stu0660-like Csn2 proteins (∼350 residues), which are larger than the known canonical Csn2 proteins (∼220 residues) by containing an extra C-terminal domain. The commonly present central channel in the two subgroups appears as a design to selectively interact with linear dsDNA. Copyright © 2012 Wiley Periodicals, Inc.

  3. 5 CFR 1215.24 - Claims involving criminal activity or misconduct.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Claims involving criminal activity or misconduct. 1215.24 Section 1215.24 Administrative Personnel MERIT SYSTEMS PROTECTION BOARD ORGANIZATION AND PROCEDURES DEBT MANAGEMENT Claims Collection § 1215.24 Claims involving criminal activity or misconduct....

  4. Ego Strength Development of Adolescents Involved in Adult-Sponsored Structured Activities.

    Science.gov (United States)

    Markstrom, Carol A.; Li, Xaioming; Blackshire, Shana L.; Wilfong, Juanita J.

    2005-01-01

    A psychosocial conception of ego strengths is presented in relation to adolescent involvement in adult-sponsored structured youth activities. Five-hundred and seventeen high school students completed measures on their involvement in structured activities and on 8 ego strengths. Gender, age, and SES were controlled in a MANCOVA procedure and it was…

  5. Identification of residues involved in nucleotidyltransferase activity of JHP933 from helicobacter pyloriby site-directed mutagenesis

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    Ye Xianren

    2016-01-01

    Full Text Available Helicobacter pylori is a well-known bacterial pathogen involved in the development of peptic ulcer, gastric adenocarcinoma and other forms of gastric cancer. Evidence has suggested that certain strain-specific genes in the plasticity region may play key roles in the pathogenesis of H. pylori-associated gastroduodenal diseases. Therefore there is considerable interest in the strain-specific genes located in the plasticity regions of H. pylori. JHP933 is encoded by the gene in the plasticity region of H. pylori strain J99. Recently, the crystal structure of JHP933 has confirmed it as a nucleotidyltransferase (NTase superfamily protein and a putative active site has been proposed. However, no evidence from direct functional assay has been presented to confirm the active site and little is known about the functional mechanism of JHP933. Here, through superimposition with Cid1/NTP complex structures, we modelled the complex structures of JHP933 with different NTPs. Based on the models and using rational site-directed mutagenesis combined with enzymatic activity assays, we confirm the active site and identify several residues important for the nucleotidyl transferring function of JHP933. Furthermore, mutations of these active site residues result in the abolishment of the nucleotidyltransferase activity of JHP933. This work provides preliminary insight into the molecular mechanism underlying the pathophysiological role in H. pylori infection of JHP933 as a novel NTase superfamily protein.

  6. Integrated analysis of bacterial and microeukaryotic communities from differentially active mud volcanoes in the Gulf of Cadiz

    Science.gov (United States)

    Coelho, Francisco J. R. C.; Louvado, António; Domingues, Patrícia M.; Cleary, Daniel F. R.; Ferreira, Marina; Almeida, Adelaide; Cunha, Marina R.; Cunha, Ângela; Gomes, Newton C. M.

    2016-10-01

    The present study assesses the diversity and composition of sediment bacterial and microeukaryotic communities from deep-sea mud volcanoes (MVs) associated with strike-slip faults in the South-West Iberian Margin (SWIM). We used a 16S/18S rRNA gene based pyrosequencing approach to characterize and correlate the sediment bacterial and microeukaryotic communities from MVs with differing gas seep regimes and from an additional site with no apparent seeping activity. In general, our results showed significant compositional changes of bacterial and microeukaryotic communities in sampling sites with different seepage regimes. Sediment bacterial communities were enriched with Methylococcales (putative methanotrophs) but had lower abundances of Rhodospirillales, Nitrospirales and SAR202 in the more active MVs. Within microeukaryotic communities, members of the Lobosa (lobose amoebae) were enriched in more active MVs. We also showed a strong correlation between Methylococcales populations and lobose amoeba in active MVs. This study provides baseline information on the diversity and composition of bacterial and microeukaryotic communities in deep-sea MVs associated with strike-slip faults.

  7. Screening of bacterial strains for pectinolytic activity: characterization of the polygalacturonase produced by Bacillus sp

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    Soares Márcia M.C.N.

    1999-01-01

    Full Text Available One hundred sixty eight bacterial strains, isolated from soil and samples of vegetable in decomposition, were screened for the use of citrus pectin as the sole carbon source. 102 were positive for pectinase depolymerization in assay plates as evidenced by clear hydrolization halos. Among them, 30% presented considerable pectinolytic activity. The cultivation of these strains by submerged and semi-solid fermentation for polygalacturonase production indicated that five strains of Bacillus sp produced high quantities of the enzyme. The physico-chemical characteristics, such as optimum pH of 6.0 - 7.0, optimum temperatures between 45oC and 55oC, stability at temperatures above 40oC and in neutral and alkaline pH, were determined.

  8. Preparation and antibacterial activity of silver nanoparticles impregnated in bacterial cellulose

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    Luiz C. S. Maria

    2010-01-01

    Full Text Available A simple method was developed to load a large amount of silver nanoparticles into bacterial cellulose (BC produced by Gluconacetobacter xylinus in a controlled manner. Due to the high electron-rich oxygen density in the BC macromolecules and the large surface area of the BC nanoporous structure as an effective nanoreactor, the in situ direct metallization technique was successfully used to synthesize Ag nanoparticles with an average diameter of 30 nm and a loading content of at least 5 wt. (%, approximately. This novel procedure provides an easy and economical way to manufacture Ag nanoparticles supported on a porous membrane for various biomedical applications. These composite fibers showed nearly 100% antibacterial activity (elimination of microorganisms against Escherichia coli because of the presence of the silver nanoparticles.

  9. A crustin isoform from black tiger shrimp, Penaeus monodon exhibits broad spectrum anti-bacterial activity

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    Debashis Banerjee

    2015-11-01

    Full Text Available Crustaceans have a powerful non-specific immune mechanism that responds to pathogen invasion and together with cellular responses, generates powerful humoral factors such as antimicrobial peptides. Crustins are a diverse class of antimicrobial peptides that are expressed by the circulating haemocytes of crustaceans. Several isoforms of this molecule are reported and in this study, one isoform from the black tiger shrimp, Penaeus monodon was cloned and expressed in Escherichia coli SG 13009. The purified recombinant crustin peptide had a molecular weight of 22 kDa and exhibited potent anti-bacterial activity in vitro against several Gram positive and Gram negative bacteria that included pathogens of aquatic animals and humans. The recombinant crustin showed a minimal inhibitory concentration of 0.5 μg ml−1 against the vibrio pathogens of shrimp, which suggests its promise for application in aquaculture.

  10. New bacterial strain of the genus Ochrobactrum with glyphosate-degrading activity.

    Science.gov (United States)

    Hadi, Faranak; Mousavi, Amir; Noghabi, Kambiz Akbari; Tabar, Hadi Ghaderi; Salmanian, Ali Hatef

    2013-01-01

    Thirty bacterial strains with various abilities to utilize glyphosate as the sole phosphorus source were isolated from farm soils using the glyphosate enrichment cultivation technique. Among them, a strain showing a remarkable glyphosate-degrading activity was identified by biochemical features and 16S rRNA sequence analysis as Ochrobactrum sp. (GDOS). Herbicide (3 mM) degradation was induced by phosphate starvation, and was completed within 60 h. Aminomethylphosphonic acid was detected in the exhausted medium, suggesting glyphosate oxidoreductase as the enzyme responsible for herbicide breakdown. As it grew even in the presence of glyphosate concentrations as high as 200 mM, Ochrobactrum sp. could be used for bioremediation purposes and treatment of heavily contaminated soils.

  11. Bacterial strains diversity in Musa spp. phyllosphere with antifungal activity against Mycosphaerella fijiensis Morelet

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    Mileidy Cruz-Martín

    2016-01-01

    Full Text Available The search for alternatives to agricultural pesticides used for the management of black Sigatoka (Mycosphaerella fijiensis Morelet includes the selection of microorganisms strains with potential for the control of this pathogen. The objective of the work was to characterize bacterial strains isolated from the phylosphere of Musa spp. with antifungal effect against M. fijiensis. A morphological, cultural, physiological and molecular characterization of the strains was performed and the antifungal activity of these strains was quantified by dual culture. It was verified the diversity of bacteria with antifungal properties against M. fijiensis present in the phylosphere of Musa spp.  In addition, it was found that the phyllosphere of these crops can be used as a source of obtaining possible biological controls of M. fijiensis.   Keywords: bacteria, biocontrol, Black Sigatoka, epiphytes

  12. Role of the T cell receptor ligand affinity in T cell activation by bacterial superantigens

    DEFF Research Database (Denmark)

    Andersen, P S; Geisler, C; Buus, S

    2001-01-01

    Similar to native peptide/MHC ligands, bacterial superantigens have been found to bind with low affinity to the T cell receptor (TCR). It has been hypothesized that low ligand affinity is required to allow optimal TCR signaling. To test this, we generated variants of Staphylococcus enterotoxin C3...... (SEC3) with up to a 150-fold increase in TCR affinity. By stimulating T cells with SEC3 molecules immobilized onto plastic surfaces, we demonstrate that increasing the affinity of the SEC3/TCR interaction caused a proportional increase in the ability of SEC3 to activate T cells. Thus, the potency...... correlation between ligand affinity and ligand potency indicating that it is the density of receptor-ligand complexes in the T cell contact area that determines TCR signaling strength....

  13. Characterization of airborne ice-nucleation-active bacteria and bacterial fragments

    Science.gov (United States)

    Šantl-Temkiv, Tina; Sahyoun, Maher; Finster, Kai; Hartmann, Susan; Augustin-Bauditz, Stefanie; Stratmann, Frank; Wex, Heike; Clauss, Tina; Nielsen, Niels Woetmann; Sørensen, Jens Havskov; Korsholm, Ulrik Smith; Wick, Lukas Y.; Karlson, Ulrich Gosewinkel

    2015-05-01

    Some bacteria have the unique capacity of synthesising ice-nucleation-active (INA) proteins and exposing them at their outer membrane surface. As INA bacteria enter the atmosphere, they may impact the formation of clouds and precipitation. We studied members of airborne bacterial communities for their capacity to catalyse ice formation and we report on the excretion of INA proteins by airborne Pseudomonas sp. We also observed for the first time that INA biological fragments outer membrane vesicles and found that two isolates could do so. However, only very few INA vesicles were released per INA cell. Thus, the source of the submicron INA proteinaceous particles that we detected in the atmosphere remains to be elucidated.

  14. Human glutaminyl cyclase and bacterial zinc aminopeptidase share a common fold and active site

    Directory of Open Access Journals (Sweden)

    Misquitta Stephanie A

    2004-02-01

    Full Text Available Abstract Background Glutaminyl cyclase (QC forms the pyroglutamyl residue at the amino terminus of numerous secretory peptides and proteins. We previously proposed the mammalian QC has some features in common with zinc aminopeptidases. We now have generated a structural model for human QC based on the aminopeptidase fold (pdb code 1AMP and mutated the apparent active site residues to assess their role in QC catalysis. Results The structural model proposed here for human QC, deposited in the protein databank as 1MOI, is supported by a variety of fold prediction programs, by the circular dichroism spectrum, and by the presence of the disulfide. Mutagenesis of the six active site residues present in both 1AMP and QC reveal essential roles for the two histidines (140 and 330, QC numbering and the two glutamates (201 and 202, while the two aspartates (159 and 248 appear to play no catalytic role. ICP-MS analysis shows less than stoichiometric zinc (0.3:1 in the purified enzyme. Conclusions We conclude that human pituitary glutaminyl cyclase and bacterial zinc aminopeptidase share a common fold and active site residues. In contrast to the aminopeptidase, however, QC does not appear to require zinc for enzymatic activity.

  15. Activation of the jasmonic acid plant defence pathway alters the composition of rhizosphere bacterial communities.

    Directory of Open Access Journals (Sweden)

    Lilia C Carvalhais

    Full Text Available Jasmonic acid (JA signalling plays a central role in plant defences against necrotrophic pathogens and herbivorous insects, which afflict both roots and shoots. This pathway is also activated following the interaction with beneficial microbes that may lead to induced systemic resistance. Activation of the JA signalling pathway via application of methyl jasmonate (MeJA alters the composition of carbon containing compounds released by roots, which are implicated as key determinants of rhizosphere microbial community structure. In this study, we investigated the influence of the JA defence signalling pathway activation in Arabidopsis thaliana on the structure of associated rhizosphere bacterial communities using 16S rRNA gene amplicon pyrosequencing. Application of MeJA did not directly influence bulk soil microbial communities but significant changes in rhizosphere community composition were observed upon activation of the jasmonate signalling pathway. Our results suggest that JA signalling may mediate plant-bacteria interactions in the soil upon necrotrophic pathogen and herbivorous insect attacks.

  16. Characterization of bacterial functional groups and microbial activity in microcosms with glyphosate application

    Science.gov (United States)

    Moyano, Sofia; Bonetto, Mariana; Baigorria, Tomas; Pegoraro, Vanesa; Ortiz, Jimena; Faggioli, Valeria; Conde, Belen; Cazorla, Cristian; Boccolini, Monica

    2017-04-01

    Glyphosate is a worldwide used herbicide as c. 90% of transgenic crops are tolerant to it. Microbial degradation of glyphosate molecule in soil is considered the most important process that determines its persistence in the environment. However, the impact of this herbicide on target groups of soil biota remains poorly understood. Our objective was to characterize the abundance of bacterial groups and global microbial activity, under controlled conditions with application of increasing doses of glyphosate. A bioassay was carried out in microcosms using an agricultural soil (Typic Argiudoll) with registered history of glyphosate application from National Institute of Agricultural Technology (INTA, EEA Marcos Juarez, Argentina). Glyphosate of commercial formulation (74.7%) was used and the following treatments were evaluated: Soil without glyphosate (control), and Soil with doses equivalent to 1.12 and 11.2 kg ai ha-1. Microbiological parameters were estimated at 3, 7, 14 and 21 days after herbicide application by counting heterotrophic, cellulolytic, nitrogen fixing (N), and nitrifying bacteria; and fluorescein diacetate hydrolysis (FDA), microbial respiration (MR) and microbial biomass (C-BM). The N cycle related bacteria showed greater sensitivity to glyphosate with significant increases in abundance. On the other hand the C cycle parameters were strongly conditioned by the time elapsed since the application of the herbicide, as did the MR. The FDA declined with the highest dose, while the C-BM was not affected. Therefore, we conclude that in the studied experimental conditions glyphosate stimulated bacterial growth (i.e. target abundances) representing a source of N, C and nutrients. On the other hand, enzymatic activity (FDA) decreased when glyphosate was applied in the highest dose, whereas, it had no effect on the MR nor C-BM, which could be attributable to the organic matter content of the soil. However, future research in field conditions is necessary, for

  17. Bacterial pathogens induce abscess formation by CD4(+) T-cell activation via the CD28-B7-2 costimulatory pathway.

    Science.gov (United States)

    Tzianabos, A O; Chandraker, A; Kalka-Moll, W; Stingele, F; Dong, V M; Finberg, R W; Peach, R; Sayegh, M H

    2000-12-01

    Abscesses are a classic host response to infection by many pathogenic bacteria. The immunopathogenesis of this tissue response to infection has not been fully elucidated. Previous studies have suggested that T cells are involved in the pathologic process, but the role of these cells remains unclear. To delineate the mechanism by which T cells mediate abscess formation associated with intra-abdominal sepsis, the role of T-cell activation and the contribution of antigen-presenting cells via CD28-B7 costimulation were investigated. T cells activated in vitro by zwitterionic bacterial polysaccharides (Zps) known to induce abscess formation required CD28-B7 costimulation and, when adoptively transferred to the peritoneal cavity of naïve rats, promoted abscess formation. Blockade of T-cell activation via the CD28-B7 pathway in animals with CTLA4Ig prevented abscess formation following challenge with different bacterial pathogens, including Staphylococcus aureus, Bacteroides fragilis, and a combination of Enterococcus faecium and Bacteroides distasonis. In contrast, these animals had an increased abscess rate following in vivo T-cell activation via CD28 signaling. Abscess formation in vivo and T-cell activation in vitro required costimulation by B7-2 but not B7-1. These results demonstrate that abscess formation by pathogenic bacteria is under the control of a common effector mechanism that requires T-cell activation via the CD28-B7-2 pathway.

  18. Peroxidase activity of bacterial cytochrome P450 enzymes: modulation by fatty acids and organic solvents.

    Science.gov (United States)

    Rabe, Kersten S; Erkelenz, Michael; Kiko, Kathrin; Niemeyer, Christof M

    2010-08-01

    The modulation of peroxidase activity by fatty acid additives and organic cosolvents was determined and compared for four bacterial cytochrome P450 enzymes, thermostable P450 CYP119A1, the P450 domain of CYP102A1 (BMP), CYP152A1 (P450(bsbeta)), and CYP101A1 (P450(cam)). Utilizing a high-throughput microplate assay, we were able to readily screen more than 100 combinations of enzymes, additives and cosolvents in a convenient and highly reproducible assay format. We found that, in general, CYP119A1 and BMP showed an increase in peroxidative activity in the presence of fatty acids, whereas CYP152A1 revealed a decrease in activity and CYP101A1 was only slightly affected. In particular, we observed that the conversion of the fluorogenic peroxidase substrate Amplex Red by CYP119A1 and BMP was increased by a factor of 38 or 11, respectively, when isopropanol and lauric acid were present in the reaction mixture. The activity of CYP119A1 could thus be modulated to reach more than 90% of the activity of CYP152A1 without effectors, which is the system with the highest peroxidative activity. For all P450s investigated we found distinctive reactivity patterns, which suggest similarities in the binding site of CYP119A1 and BMP in contrast with the other two proteins studied. Therefore, this study points towards a role of fatty acids as activators for CYP enzymes in addition to being mere substrates. In general, our detailed description of fatty acid- and organic solvent-effects is of practical interest because it illustrates that optimization of modulators and cosolvents can lead to significantly increased yields in biocatalysis.

  19. Fragmented Lactic Acid Bacterial Cells Activate Peroxisome Proliferator-Activated Receptors and Ameliorate Dyslipidemia in Obese Mice.

    Science.gov (United States)

    Nakamura, Futoshi; Ishida, Yu; Sawada, Daisuke; Ashida, Nobuhisa; Sugawara, Tomonori; Sakai, Manami; Goto, Tsuyoshi; Kawada, Teruo; Fujiwara, Shigeru

    2016-03-30

    Recent studies suggest that peroxisome proliferator-activated receptor (PPAR) activation ameliorates metabolic disorders, including dyslipidemia. To identify an effective PPAR agonist, we screened the in vitro PPARα/γ activation ability of organic solvent extracts from food-oriented bacterial strains belonging to 5 genera and 32 species, including lactic acid bacteria, and of these, Lactobacillus amylovorus CP1563 demonstrated the highest PPARα/γ agonist activity. We also found that physical fragmentation of the strain could substitute organic solvent extraction for the expression of CP1563 activity in vitro. For functional food manufacturing, we selected the fragmented CP1563 and conducted subsequent animal experiments. In an obese mouse model, we found that treatment with fragmented CP1563 for 12 weeks decreased the levels of low-density lipoprotein (LDL)-cholesterol and triglyceride in plasma, significantly decreased the atherosclerosis index, and increased the plasma high-density lipoprotein (HDL)-cholesterol level. Thus, we conclude that fragmented CP1563 may be a candidate for the prevention and treatment of dyslipidemia.

  20. Bacterial Cytotoxins Target Rho GTPases

    Science.gov (United States)

    Schmidt, Gudula; Aktories, Klaus

    1998-06-01

    Low molecular mass GTPases of the Rho family, which are involved in the regulation of the actin cytoskeleton and in various signal transduction processes, are the eukaryotic targets of bacterial protein toxins. The toxins covalently modify Rho proteins by ADP ribosylation, glucosylation, and deamidation, thereby inactivating and activating the GTPases.

  1. Effect of platelet-activating factor antagonists (BN-52021, WEB-2170, and BB-882) on bacterial translocation in acute pancreatitis.

    Science.gov (United States)

    de Souza, L J; Sampietre, S N; Assis, R S; Knowles, C H; Leite, K R; Jancar, S; Monteiro Cunha, J E; Machado, M C

    2001-01-01

    Bacterial translocation is an important source of pancreas infection in acute pancreatitis. The effect of platelet-activating factor (PAF) in the pathogenesis of acute pancreatitis has been proved in various studies. The aim of this study was to determine whether potent PAF antagonists influence bacterial translocation in acute pancreatitis. Acute pancreatitis was induced in 62 Wistar rats by injection of 2.5% sodium taurocholate into the biliopancreatic duct. The rats treated with PAF factor antagonists received intravenous injection of WEB-2170 (10 mg/kg), lexipafant (5 mg/kg), and BN-52021 (5 mg/kg) 30 minutes before induction of acute pancreatitis. Six hours after induction of acute pancreatitis, bacteriologic cultures and histologic scoring of tissues were performed. There was a statistically significant reduction in bacterial translocation to the mesenteric lymph nodes and liver but not to the pancreas of the rats treated with PAF antagonists. No significant increase in the intestinal bacterial population of any group was found. There were no statistical differences between the pancreatic histologic scores of the groups. PAF antagonists reduced bacterial translocation to distant sites other than the pancreas, preventing the bacterial dissemination that occurs in the early phase of acute pancreatitis and may have beneficial effects on the evolution of this disease.

  2. Active wound dressings based on bacterial nanocellulose as drug delivery system for octenidine.

    Science.gov (United States)

    Moritz, Sebastian; Wiegand, Cornelia; Wesarg, Falko; Hessler, Nadine; Müller, Frank A; Kralisch, Dana; Hipler, Uta-Christina; Fischer, Dagmar

    2014-08-25

    Although bacterial nanocellulose (BNC) may serve as an ideal wound dressing, it exhibits no antibacterial properties by itself. Therefore, in the present study BNC was functionalized with the antiseptic drug octenidine. Drug loading and release, mechanical characteristics, biocompatibility, and antimicrobial efficacy were investigated. Octenidine release was based on diffusion and swelling according to the Ritger-Peppas equation and characterized by a time dependent biphasic release profile, with a rapid release in the first 8h, followed by a slower release rate up to 96 h. The comparison between lab-scale and up-scale BNC identified thickness, water content, and the surface area to volume ratio as parameters which have an impact on the control of the release characteristics. Compression and tensile strength remained unchanged upon incorporation of octenidine in BNC. In biological assays, drug-loaded BNC demonstrated high biocompatibility in human keratinocytes and antimicrobial activity against Staphylococcus aureus. In a long-term storage test, the octenidine loaded in BNC was found to be stable, releasable, and biologically active over a period of 6 months without changes. In conclusion, octenidine loaded BNC presents a ready-to-use wound dressing for the treatment of infected wounds that can be stored over 6 months without losing its antibacterial activity. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Enzymatic activity of endophytic bacterial isolates of Jacaranda decurrens Cham. (Carobinha-do-campo

    Directory of Open Access Journals (Sweden)

    Aysha Jussara Ivonilde Carrim

    2006-05-01

    Full Text Available The objectives of this work was to isolate endophytic bacteria from Jacaranda decurrens Cham. and screening of some enzymes of biotechnological interest. Ten (10 bacterial species were isolated and identified from the leaves and steams. All the isolates presented enzymatic activity, which was ranked as follows: proteolytic (60% and amilolytic activity (60%, lipolytic (40%, esterasic (40%. However, cellulolytic and pectinolytic activities were not detected. This is the first report on the isolation and identification of endophytic bacteria from Jacaranda decurrens Cham.O objetivo deste trabalho foi isolar bactérias endofíticas de Jacaranda decurrens Cham. e selecionar algumas enzimas de interesse biotecnológico. Dez espécies de bactérias foram isoladas e identificadas de caule e folhas. Todos os isolados de apresentaram atividade enzimática, e a maior predominância foi de atividade proteolítica (60% e atividade amilolítica (60%, seguidas atividades lipolítica (40% e esterásica (40%. Contudo, as atividades celulolítica e pectinolítica não foram detectadas. Este é o primeiro relato de isolamento e identificação de bactérias presentes em Jacaranda decurrens Cham.

  4. Anti-bacterial activities and phytochemical screening of extracts of different parts of Thalictrum rhynchocarpum.

    Science.gov (United States)

    Mayeku, Philip Wafula; Hassanali, Ahmed; Kiremire, Bernard Turyagenda; Odalo, Josiah Ochieng; Hertweck, Christian

    2013-01-01

    Parts of the plant Thalictrum rhyncocarpum are used in herbal medicine in Kenya to treat various infections. The aim of this study was to evaluate in-vitro anti-bacteria activities and phytochemical profiles of solvent extracts of the leaves, stem bark and root of Thalictrum rhyncocarpum against Bacillus subtilis-6633, Staphylococcus aures-SG 511, Escherichia coli SG 458, Pseudomonus aeruginosa-K799/61 and Mycobacterium vaccae-10670. Anti-bacterial activity tests were carried out using disc diffusion assay and tube dilution technique, and phytochemical screening was carried out through Thin Layer Chromatography. The crude extracts showed antibacterial effects on M. vaccae, P. aeruginosa and B. subtilis. M. vaccae was most sensitive, particularly to the methanol root extract. Phytochemical screening of the extracts suggested the presence of glycosides and alkaloids in the stem bark and root extracts, and flavonoids and triterpenes in the leaf extracts. The study showed interesting levels of activities of solvent extracts of different parts of T. rhyncocarpum against some of the bacteria tested (M. vaccae, P. aeruginosa and B. subtilis). The results provide some scientific rationale for the traditional use of the plant in Kenya to treat different microbial infections.

  5. Receptor-binding domain of ephrin-A1: production in bacterial expression system and activity.

    Science.gov (United States)

    Nekrasova, O V; Sharonov, G V; Tikhonov, R V; Kolosov, P M; Astapova, M V; Yakimov, S A; Tagvey, A I; Korchagina, A A; Bocharova, O V; Wulfson, A N; Feofanov, A V; Kirpichnikov, M P

    2012-12-01

    Eph receptor tyrosine kinases and their ligands, the ephrins, perform an important regulatory function in tissue organization, as well as participate in malignant transformation of cells. Ephrin-A1, a ligand of A class Eph receptors, is a modulator of tumor growth and progression, and the mechanism of its action needs detailed investigation. Here we report on the development of a system for bacterial expression of an ephrin-A1 receptor-binding domain (eA1), a procedure for its purification, and its renaturation with final yield of 50 mg/liter of culture. Functional activity of eA1 was confirmed by immunoblotting, laser scanning confocal microscopy, and flow cytometry. It is shown that monomeric non-glycosylated receptor-binding domain of ephrin-A1 is able to activate cellular EphA2 receptors, stimulating their phosphorylation. Ligand eA1 can be used to study the features of ephrin-A1 interactions with different A class Eph receptors. The created expression cassette is suitable for the development of ligands with increased activity and selectivity and experimental systems for the delivery of cytotoxins into tumor cells that overexpress EphA2 or other class A Eph receptors.

  6. Antibiofilm Activity, Compound Characterization, and Acute Toxicity of Extract from a Novel Bacterial Species of Paenibacillus

    Directory of Open Access Journals (Sweden)

    Saad Musbah Alasil

    2014-01-01

    Full Text Available The effectiveness of many antimicrobial agents is currently decreasing; therefore, it is important to search for alternative therapeutics. Our study was carried out to assess the in vitro antibiofilm activity using microtiter plate assay, to characterize the bioactive compounds using Ultra Performance Liquid Chromatography-Diode Array Detection and Liquid Chromatography-Mass Spectrometry and to test the oral acute toxicity on Sprague Dawley rats of extract derived from a novel bacterial species of Paenibacillus strain 139SI. Our results indicate that the crude extract and its three identified compounds exhibit strong antibiofilm activity against a broad range of clinically important pathogens. Three potential compounds were identified including an amino acid antibiotic C8H20N3O4P (MW 253.237, phospholipase A2 inhibitor C21H36O5 (MW 368.512, and an antibacterial agent C14H11N3O2 (MW 253.260. The acute toxicity test indicates that the mortality rate among all rats was low and that the biochemical parameters, hematological profile, and histopathology examination of liver and kidneys showed no significant differences between experimental groups P>0.05. Overall, our findings suggest that the extract and its purified compounds derived from novel Paenibacillus sp. are nontoxic exhibiting strong antibiofilm activity against Gram-positive and Gram-negative pathogens that can be useful towards new therapeutic management of biofilm-associated infections.

  7. Phenotypic diversity and emerging new tools to study macrophage activation in bacterial infectious diseases

    Directory of Open Access Journals (Sweden)

    Jean-Louis eMege

    2014-10-01

    Full Text Available Macrophage polarization is a concept that has been useful to describe the different features of macrophage activation related to specific functions. Macrophage polarization is responsible for a dichotomic approach (killing versus repair of the host response to bacteria: M1-type conditions are protective, whereas M2-type conditions are associated with bacterial persistence. The use of the polarization concept to classify the features of macrophage activation in infected patients using transcriptional and/or molecular data and to provide biomarkers for diagnosis and prognosis has most often been unsuccessful. The confrontation of polarization with different clinical situations in which monocytes/macrophages encounter bacteria obliged us to reappraise this concept. With the exception of M2-type infectious diseases such as leprosy and Whipple’s disease, most acute (sepsis or chronic (Q fever, tuberculosis infectious diseases do not exhibit polarized monocytes/macrophages. This is also the case for commensals that shape the immune response and for probiotics that alter the immune response independent of macrophage polarization. We propose that the type of myeloid cells (monocytes vs. macrophages and the kinetics of the immune response (early vs. late responses are critical variables for understanding macrophage activation in human infectious diseases. Explorating the role of these new markers will provide important tools to better understand complex macrophage physiology.

  8. Bacterial composition of activated sludge - importance for floc and sludge properties

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Per H.; Thomsen, Trine R.; Nielsen, Jeppe L.

    2003-07-01

    Activated sludge flocs consist of numerous constituents which, together with other factors, are responsible for floc structure and floc properties. These properties largely determine the sludge properties such as flocculation, settling and dewaterability. In this paper we briefly review the present knowledge about the role of bacteria in relation to floc and sludge properties, and we present a new approach to investigate the identity and function of the bacteria in the activated sludge flocs. The approach includes identification of the important bacteria and a characterization of their physiological and functional properties. It is carried out by use of culture-independent molecular biological methods linked with other methods to study the physiology and function maintaining a single cell resolution. Using this approach it was found that floc-forming properties differed among the various bacterial groups, e.g. that different microcolony-forming bacteria had very different sensitivities to shear and that some of them deflocculated under anaerobic conditions. in our opinion, the approach to combine identity with functional analysis of the dominant bacteria in activated sludge by in situ methods is a very promising way to investigate correlations between presence of specific bacteria, and floc and sludge properties that are of interest. (author)

  9. Effects of Cistus-tea on bacterial colonization and enzyme activities of the in situ pellicle.

    Science.gov (United States)

    Hannig, Christian; Spitzmüller, Bettina; Al-Ahmad, Ali; Hannig, Matthias

    2008-07-01

    Polyphenols are expected to have antibacterial properties. Cistus is a tea rich in polyphenols. The aim of the present in situ study was to investigate the effect of Cistus-tea on the pellicle and on the initial oral biofilm. For in situ pellicle formation and initial biofilm formation, bovine enamel slabs were fixed on maxillary splints and carried by four subjects at buccal sites for up to 2 h. Bacteria present in 120-min pellicles were determined with DAPI-staining and fluorescence in situ hybridization with and without a 10 min rinse with Cistus-tea performed 1 min after incorporation of the slabs. In addition, amylase, lysozyme, glucosyltransferase and peroxidase activities immobilised in the pellicle layer were measured before and after rinsing for 10 min with Cistus-tea. The amount of bacteria detected in the 120-min biofilm was reduced significantly, if a 10 min rinse with Cistus-tea was performed one min after insertion of the enamel slabs. DAPI-staining yielded 13.2+/-3.5 for controls and 6.5+/-1.1 x 10(4) bacteria/cm(2), if a rinse with Cistus-tea was applied. Lysozyme, amylase and glucosyltransferase activities immobilised in the pellicle were not affected following a rinse with Cistus-tea. However, peroxidase activity was reduced significantly. Cistus-tea may be used to reduce the initial bacterial adhesion in the oral cavity.

  10. Frequency of dental caries in active and inactive systemic lupus erythematous patients: salivary and bacterial factors.

    Science.gov (United States)

    Loyola Rodriguez, J P; Galvan Torres, L J; Martinez Martinez, R E; Abud Mendoza, C; Medina Solis, C E; Ramos Coronel, S; Garcia Cortes, J O; Domínguez Pérez, R A

    2016-10-01

    The objective of this study was to determine dental caries frequency and to analyze salivary and bacterial factors associated with active and inactive systemic lupus erythematous (SLE) patients. Also, a proposal to identify dental caries by a surface, teeth, and the patient was developed. A cross-sectional, blinded study that included 60 SLE patients divided into two groups of 30 subjects each, according to the Activity Index for Diagnosis of Systemic Lupus Erythematous (SLEDAI). The decayed, missing, and filled teeth (DMFT) index and Integrative Dental Caries Index (IDCI) were used for analyzing dental caries. The saliva variables recorded were: flow, pH, and buffer capacity. The DNA copies of Streptococcus mutans and Streptococcus sobrinus were estimated by real-time PCR. The caries frequency was 85% for SLE subjects (73.3% for inactive systemic lupus erythematous (ISLE) and 100% for active systemic lupus erythematous (ASLE)); DMFT for the SLE group was 12.6 ± 5.7 and the IDCI was (9.8 ± 5.9). The ASLE group showed a salivary flow of 0.65 compared with 0.97 ml/1 min from the ISLE group; all variables mentioned above showed a statistical difference (p dental caries in epidemiological studies. © The Author(s) 2016.

  11. CHEMICALLY FABRICATED SILVER NANOPARTICLES ENHANCES THE ACTIVITY OF ANTIBIOTICS AGAINST SELECTED HUMAN BACTERIAL PATHOGENS

    Directory of Open Access Journals (Sweden)

    S. Thangapandiyan and P. Prema*

    2012-05-01

    Full Text Available Due to the outbreak of infectious diseases caused by different pathogenic bacteria and the development of antibiotic resistance, the pharmaceutical companies and the researchers are now searching for new unconventional antibacterial agents. Nanotechnology represents a modern and innovative approach to develop new formulations based on metallic nanoparticles with antimicrobial properties. The potential bioactivity of chemically fabricated silver nanoparticles has been extensively studied. However, the antibacterial activity of silver nanoparticles individually or in combination with different antibiotics has not been demonstrated. In the present investigations, the effect of silver nanoparticles on the antibacterial activity of different antibiotics was evaluated against selected human bacterial pathogens such as Staphylococcus aureus, Streptococcus epidermis, Escherichia coli, Pseudomonas aeruginosa, and Bacillus cereus by disc diffusion method. In the presence of sub - inhibitory concentration of silver nanoparticles (100µL/disc, the antibacterial activities of all antibiotics are increased from 1 mm to 10 mm. The maximum fold increase was noticed for vancomycin against Pseudomonas aeruginosa (66.67%, Escherichia coli (62.50%, and Staphylococcus aureus (46% followed by rifampicin against Bacillus cereus (66.67% and kanamycin against Streptococcus epidermis (25%. These results signify that the silver nanoparticles showed potential antibacterial action of ß-lactams, glycopeptides, aminoglycosides, sulphonamides suggesting a possible utilization of silver nanocompounds in combination therapy against selected pathogens used in the experiment.

  12. Bacterial production, glucosidase activity and particle-associated carbohydrates in Dona Paula bay, west coast of India

    Science.gov (United States)

    Bhaskar, P. V.; Bhosle, N. B.

    2008-11-01

    Size-fractionated bacterial production, abundance and α- and β- glucosidase enzyme activities were studied with respect to changes in hydrography, total suspended matter (TSM), chlorophyll a, particulate organic carbon and nitrogen ratio (POC:PON), 1.5 M NaCl-soluble and 10 mM EDTA-soluble carbohydrates (Sal-PCHO and CPCHO) and transparent exopolymeric particles (TEP) in the surface waters from July 1999-2000 at a shallow coastal station in Dona Paula Bay, west coast of India. The bulk of the total bacterial production and glucosidase activity were associated with particles (75% and >80%, respectively). Total bacterial production was linearly correlated to chlorophyll a ( r = 0.513; p Paula Bay.

  13. Antibacterial activity of Thymoquinone, an active principle of Nigella sativa and its potency to prevent bacterial biofilm formation

    Directory of Open Access Journals (Sweden)

    Bakhrouf Amina

    2011-04-01

    Full Text Available Abstract Background Thymoquinone is an active principle of Nigella sativa seed known as "Habbah Al-Sauda" in Arabic countries and "Sinouj" in Tunisia. Bacterial biofilms tend to exhibit significant tolerance to antimicrobials drugs during infections. Methods The antibacterial activity of Thymoquinone (TQ and its biofilm inhibition potencies were investigated on 11 human pathogenic bacteria. The growth and development of the biofilm were assessed using the crystal violet (CV and the 2, 3-bis [2-methyloxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide (XTT reduction assay. Results TQ exhibited a significant bactericidal activity against the majority of the tested bacteria (MICs values ranged from 8 to 32 μg/ml especially Gram positive cocci (Staphylococcus aureus ATCC 25923 and Staphylococcus epidermidis CIP 106510. Crystal violet assay demonstrated that the minimum biofilm inhibition concentration (BIC50 was reached with 22 and 60 μg/ml for Staphylococcus aureus ATCC 25923 and Staphylococcus epidermidis CIP 106510 respectively. In addition our data revealed that cells oxidative activity was influenced by TQ supplementation. In the same way, TQ prevented cell adhesion to glass slides surface. Conclusion The ability of TQ to prevent biofilm formation warrants further investigation to explore its use as bioactive substances with antibiofilm potential.

  14. [Bacterial outer membrane vesicles as nano carriers to study immunological activities].

    Science.gov (United States)

    Qi, Chen; Min, W U; Hongzhen, Bai; Zeling, Guo; Jun, Zhou; Qingqing, Wang; Guping, Tang

    2017-03-25

    Objective: To prepare a nano-carrier based on combining bacterial outer membrane vesicles (OMV) with three block polymer pluronic F127 (PEO100-PPO65-PEO100) (OMV-F127) and to investigate its immunological activity. Methods: Attenuated salmonella (sal) was cultivated. OMV were separated by centrifugal ultrafiltration or ultrasonication, and OMV-F127 was prepared by mechanical extrudation method. The protein contents and compositions were tested with BCA and SDS-PAGE; the morphology of OMV, F127 and OMV-F127 were observed with FM and TEM; the particle sizes and their zeta potential were determined with DLS. Mouse macrophage RAW246.7 cells were treated with OMV-F127 (50 μg/mL, 100 μg/mL) in vitro, and the concentrations of IL-12, TNF-α and IFN-γ in culture supernatant were measured with ELISA kits. Results: The contents of protein in separated OMV by centrifugal ultrafiltration and ultrasonication were 2.8 mg/mL and 2.7 mg/mL, respectively. SDS-PAGE showed the marker protein OmpF/C in OMV. Under the FM and TEM, ball-like structure of F127 and OMV-F127 was observed. Size analysis revealed that the diameters of OMV, F127 and OMV-F127 were 72±2 nm, 90±3 nm and 92±2 nm, respectively. ELISA tests revealed that OMV-F127 significantly stimulated the secretion of IL-12, TNF-α and IFN-γ in RAW246.7 cells. Conclusion: A nano-carrier based on bacterial outer membrane vesicles has been prepared, which can stimulate the secretion of cytokines and may have immunomodulatory effects.

  15. The bacterial SRP receptor, FtsY, is activated on binding to the translocon

    National Research Council Canada - National Science Library

    Draycheva, Albena; Bornemann, Thomas; Ryazanov, Sergey; Lakomek, Nils‐Alexander; Wintermeyer, Wolfgang

    2016-01-01

    Proteins are inserted into the bacterial plasma membrane cotranslationally after translating ribosomes are targeted to the translocon in the membrane via the signal recognition particle (SRP) pathway...

  16. Diversity and biological activities of the bacterial community associated with the marine sponge Phorbas tenacior (Porifera, Demospongiae).

    Science.gov (United States)

    Dupont, S; Carré-Mlouka, A; Descarrega, F; Ereskovsky, A; Longeon, A; Mouray, E; Florent, I; Bourguet-Kondracki, M L

    2014-01-01

    The diversity of the cultivable microbiota of the marine sponge Phorbas tenacior frequently found in the Mediterranean Sea was investigated, and its potential as a source of antimicrobial, antioxidant and antiplasmodial compounds was evaluated. The cultivable bacterial community was studied by isolation, cultivation and 16S rRNA gene sequencing. Twenty-three bacterial strains were isolated and identified in the Proteobacteria (α or γ classes) and Actinobacteria phyla. Furthermore, three different bacterial morphotypes localized extracellularly within the sponge tissues were revealed by microscopic observations. Bacterial strains were assigned to seven different genera, namely Vibrio, Photobacterium, Shewanella, Pseudomonas, Ruegeria, Pseudovibrio and Citricoccus. The strains affiliated to the same genus were differentiated according to their genetic dissimilarities using random amplified polymorphic DNA (RAPD) analyses. Eleven bacterial strains were selected for evaluation of their bioactivities. Three isolates Pseudovibrio P1Ma4, Vibrio P1MaNal1 and Citricoccus P1S7 revealed antimicrobial activity; Citricoccus P1S7 and Vibrio P1MaNal1 isolates also exhibited antiplasmodial activity, while two Vibrio isolates P1Ma8 and P1Ma5 displayed antioxidant activity. These data confirmed the importance of Proteobacteria and Actinobacteria associated with marine sponges as a reservoir of bioactive compounds. This study presents the first report on the diversity of the cultivable bacteria associated with the marine sponge Phorbas tenacior, frequently found in the Mediterranean Sea. Evaluation of the antiplasmodial, antimicrobial and antioxidant activities of the isolates has been investigated and allowed to select bacterial strains, confirming the importance of Proteobacteria and Actinobacteria as sources of bioactive compounds. © 2013 The Society for Applied Microbiology.

  17. Parameters that enhance the bacterial expression of active plant polyphenol oxidases.

    Directory of Open Access Journals (Sweden)

    Mareike E Dirks-Hofmeister

    Full Text Available Polyphenol oxidases (PPOs, EC 1.10.3.1 are type-3 copper proteins that enzymatically convert diphenolic compounds into their corresponding quinones. Although there is significant interest in these enzymes because of their role in food deterioration, the lack of a suitable expression system for the production of soluble and active plant PPOs has prevented detailed investigations of their structure and activity. Recently we developed a bacterial expression system that was sufficient for the production of PPO isoenzymes from dandelion (Taraxacum officinale. The system comprised the Escherichia coli Rosetta 2 (DE3 [pLysSRARE2] strain combined with the pET-22b(+-vector cultivated in auto-induction medium at a constant low temperature (26 °C. Here we describe important parameters that enhance the production of active PPOs using dandelion PPO-2 for proof of concept. Low-temperature cultivation was essential for optimal yields, and the provision of CuCl2 in the growth medium was necessary to produce an active enzyme. By increasing the copper concentration in the production medium to 0.2 mM, the yield in terms of PPO activity per mol purified protein was improved 2.7-fold achieving a v(max of 0.48 ± 0.1 µkat per mg purified PPO-2 for 4-methylcatechol used as a substrate. This is likely to reflect the replacement of an inactive apo-form of the enzyme with a correctly-folded, copper-containing counterpart. We demonstrated the transferability of the method by successfully expressing a PPO from tomato (Solanum lycopersicum showing that our optimized system is suitable for the analysis of further plant PPOs. Our new system therefore provides greater opportunities for the future of research into this economically-important class of enzymes.

  18. Mass Spectrometric Detection of Bacterial Protein Toxins and Their Enzymatic Activity.

    Science.gov (United States)

    Kalb, Suzanne R; Boyer, Anne E; Barr, John R

    2015-08-31

    Mass spectrometry has recently become a powerful technique for bacterial identification. Mass spectrometry approaches generally rely upon introduction of the bacteria into a matrix-assisted laser-desorption time-of-flight (MALDI-TOF) mass spectrometer with mass spectrometric recognition of proteins specific to that organism that form a reliable fingerprint. With some bacteria, such as Bacillus anthracis and Clostridium botulinum, the health threat posed by these organisms is not the organism itself, but rather the protein toxins produced by the organisms. One such example is botulinum neurotoxin (BoNT), a potent neurotoxin produced by C. botulinum. There are seven known serotypes of BoNT, A-G, and many of the serotypes can be further differentiated into toxin variants, which are up to 99.9% identical in some cases. Mass spectrometric proteomic techniques have been established to differentiate the serotype or toxin variant of BoNT produced by varied strains of C. botulinum. Detection of potent biological toxins requires high analytical sensitivity and mass spectrometry based methods have been developed to determine the enzymatic activity of BoNT and the anthrax lethal toxins produced by B. anthracis. This enzymatic activity, unique for each toxin, is assessed with detection of the toxin-induced cleavage of strategically designed peptide substrates by MALDI-TOF mass spectrometry offering unparalleled specificity. Furthermore, activity assays allow for the assessment of the biological activity of a toxin and its potential health risk. Such methods have become important diagnostics for botulism and anthrax. Here, we review mass spectrometry based methods for the enzymatic activity of BoNT and the anthrax lethal factor toxin.

  19. Application of activated charcoal in the downstream processing of bacterial olefinic poly(3-hydroxyalkanoates).

    Science.gov (United States)

    Wampfler, Bruno; Ramsauer, Thomas; Kehl, Karl; Zinn, Manfred; Thöny-Meyer, Linda

    2010-01-01

    Medium chain length poly(hydroxyalkanoates) (mcl-PHAs) are bacterial thermoplastic elastomers with a large potential in medical applications. The present study provides a novel process to isolate and purify poly([R]-3-hydroxy-omega-undecenoate-co-3-hydroxy-omega-nonenoate-co-3-hydroxy-omega-heptenoate) (PHUE) and poly([R]-3-hydroxy-omega-undecenoate-co-3-hydroxy-omega-nonenoate-co-3-hydroxyoctanoate-co-3-hydroxy-omega-heptenoate-co-3-hydroxyhexanoate) (PHOUE) from Pseudomonas putida species. Three different types of activated charcoal were compared with regard to their capability to selectively remove impurities. The product 'Charcoal activated, powder, pure' from Merck was found to be most suitable. Using ethyl acetate as solvent, the polyesters were extracted from freeze-dried biomass at room temperature and simultaneously purified by addition of activated charcoal at the beginning of the extraction. The period of extraction was one hour and the ratio solvent to biomass was 15:1 (vol/wt). After extraction, the solids were separated by pressure filtration through a metallic lace tissue. The filtrate was again passed through the previously accumulated filter cake, followed by a second filtration through a 0.45 microm membrane to remove finest coal particles. The resulting filtrate was concentrated, thus yielding polyesters whose quality and yield depended on the quantity of activated charcoal applied. For highly pure PHUE and PHOUE with low endotoxin levels, the optimum ratio of activated charcoal to solvent for extraction (V/V) was found to be 0.5 for PHUE and 0.25 for PHOUE. The yields with regard to the raw polymers amounted to 55 wt% for PHUE and 75 wt% for PHOUE, which are acceptable for polymers that can be used for medical applications.

  20. Parent Involvement in Early Childhood Special Education: Selected Activities for Preschool Teachers.

    Science.gov (United States)

    Carlson, Betty Clark

    The manual is designed to provide special education preschool teachers with a guide for parent involvement activities. The guide presents 32 activities divided into three topical areas: (1) communicating with parents (orientation packet, newsletter, school-home notebook, bulletin board for parents); (2) resource activities (field trips, home…

  1. Methanotrophic activity and bacterial diversity in volcanic-geothermal soils at Pantelleria island (Italy)

    Science.gov (United States)

    Gagliano, A. L.; D'Alessandro, W.; Tagliavia, M.; Parello, F.; Quatrini, P.

    2014-04-01

    Volcanic and geothermal systems emit endogenous gases by widespread degassing from soils, including CH4, a greenhouse gas twenty-five times as potent as CO2. Recently, it has been demonstrated that volcanic/geothermal soils are source of methane, but also sites of methanotrophic activity. Methanotrophs are able to consume 10-40 Tg of CH4 a-1 and to trap more than 50% of the methane degassing through the soils. We report on methane microbial oxidation in the geothermally most active site of Pantelleria island (Italy), Favara Grande, whose total methane emission was previously estimated in about 2.5 t a-1. Laboratory incubation experiments with three top-soil samples from Favara Grande indicated methane consumption values up to 950 ng g-1 dry soil h-1. One of the three sites, FAV2, where the highest oxidation rate was detected, was further analysed on a vertical soil profile and the maximum methane consumption was measured in the top-soil layer but values > 100 ng g-1 h-1 were maintained up to a depth of 15 cm. The highest consumption rate was measured at 37 °C, but a still recognizable consumption at 80 °C (> 20 ng g-1 h-1) was recorded. In order to estimate the bacterial diversity, total soil DNA was extracted from Favara Grande and analysed using a Temporal Temperature Gradient gel Electrophoresis (TTGE) analysis of the amplified bacterial 16S rRNA gene. The three soil samples were probed by PCR using standard proteobacterial primers and newly designed verrucomicrobial primers targeting the unique methane monooxygenase gene pmoA; the presence of methanotrophs was detected in sites FAV2 and FAV3, but not in FAV1, where harsher chemical-physical conditions and negligible methane oxidation were detected. The pmoA gene libraries from the most active site FAV2 pointed out a high diversity of gammaproteobacterial methanotrophs distantly related to Methylococcus/Methylothermus genera and the presence of the newly discovered acido-thermophilic methanotrophs

  2. Systematically Altering Bacterial SOS Activity under Stress Reveals Therapeutic Strategies for Potentiating Antibiotics.

    Science.gov (United States)

    Mo, Charlie Y; Manning, Sara A; Roggiani, Manuela; Culyba, Matthew J; Samuels, Amanda N; Sniegowski, Paul D; Goulian, Mark; Kohli, Rahul M

    2016-01-01

    The bacterial SOS response is a DNA damage repair network that is strongly implicated in both survival and acquired drug resistance under antimicrobial stress. The two SOS regulators, LexA and RecA, have therefore emerged as potential targets for adjuvant therapies aimed at combating resistance, although many open questions remain. For example, it is not well understood whether SOS hyperactivation is a viable therapeutic approach or whether LexA or RecA is a better target. Furthermore, it is important to determine which antimicrobials could serve as the best treatment partners with SOS-targeting adjuvants. Here we derived Escherichia coli strains that have mutations in either lexA or recA genes in order to cover the full spectrum of possible SOS activity levels. We then systematically analyzed a wide range of antimicrobials by comparing the mean inhibitory concentrations (MICs) and induced mutation rates for each drug-strain combination. We first show that significant changes in MICs are largely confined to DNA-damaging antibiotics, with strains containing a constitutively repressed SOS response impacted to a greater extent than hyperactivated strains. Second, antibiotic-induced mutation rates were suppressed when SOS activity was reduced, and this trend was observed across a wider spectrum of antibiotics. Finally, perturbing either LexA or RecA proved to be equally viable strategies for targeting the SOS response. Our work provides support for multiple adjuvant strategies, while also suggesting that the combination of an SOS inhibitor with a DNA-damaging antibiotic could offer the best potential for lowering MICs and decreasing acquired drug resistance. IMPORTANCE Our antibiotic arsenal is becoming depleted, in part, because bacteria have the ability to rapidly adapt and acquire resistance to our best agents. The SOS pathway, a widely conserved DNA damage stress response in bacteria, is activated by many antibiotics and has been shown to play central role in

  3. Antimicrobial Activity of Marine Bacterial Symbionts Retrieved from Shallow Water Hydrothermal Vents.

    Science.gov (United States)

    Eythorsdottir, Arnheidur; Omarsdottir, Sesselja; Einarsson, Hjorleifur

    2016-06-01

    Marine sponges and other sessile macro-organisms were collected at a shallow water hydrothermal site in Eyjafjörður, Iceland. Bacteria were isolated from the organisms using selective media for actinomycetes, and the isolates were screened for antimicrobial activity. A total of 111 isolates revealed antimicrobial activity displaying different antimicrobial patterns which indicates production of various compounds. Known test strains were grown in the presence of ethyl acetate extracts from one selected isolate, and a clear growth inhibition of Staphylococcus aureus was observed down to 0.1 % extract concentration in the medium. Identification of isolates shows different species of Actinobacteria with Streptomyces sp. playing the largest role, but also members of Bacilli, Alphaproteobacteria and Gammaproteobacteria. Sponges have an excellent record regarding production of bioactive compounds, often involving microbial symbionts. At the hydrothermal vents, however, the majority of active isolates originated from other invertebrates such as sea anemones or algae. The results indicate that antimicrobial assays involving isolates in full growth can detect activity not visible by other methods. The macro-organisms inhabiting the Eyjafjörður hydrothermal vent area host diverse microbial species in the phylum Actinobacteria with antimicrobial activity, and the compounds responsible for the activity will be subject to further research.

  4. Metabolic activity of bacterial cell enumerated by direct viable count. [Escherichia coli; Salmonella enteritidis

    Energy Technology Data Exchange (ETDEWEB)

    Roszak, D.B.; Colwell, R.R.

    1987-12-01

    The direct viable count (DVC) method was modified by incorporation radiolabeled substrates in microautoradiographic analyses to assess bacterial survival in controlled laboratory microcosms. The DVC method, which permits enumeration of culturable and nonculturable cells, discriminates those cells that are responsive to added nutrients but in which division is inhibited by the addition of nalidixic acid. The resulting elongated cells represent all viable cells; this includes those that are culturable on routine media and those that are not. Escherichia coli and Salmonella enteritidis were employed in the microcosm studies, and radiolabeled substrates included (methyl-/sup 3/H) thymidine or (U-/sup 14/C) glutamic acid. Samples taken at selected intervals during the survival experiments were examined by epifluorescence microscopy to enumerate cells by the DVC and acridine orange direct count methods, as well as by culture methods. Good correlation was obtained for cell-associated metabolic activity, measured by microautoradiography and substrate responsiveness (by the DVC method) at various stages of survival. Of the cells responsive to nutrients by the DVC method, ca. 90% were metabolically active by the microautoradiographic method. No significant difference was observed between DVC enumerations with or without added radiolabeled substrate.

  5. Active Anti-Microbial Effects of Larch and Pine Wood on Four Bacterial Strains

    Directory of Open Access Journals (Sweden)

    Christina M. Laireiter

    2013-11-01

    Full Text Available Active anti-microbial effects of larch (Larix decidua Mill. and pine (Pinus sylvestris L. wood materials on Staphylococcus aureus, Pseudomonas aeruginosa, Enterococcus faecium, and Bacillus subtilis were tested. The agar-diffusion test, a method used in routine diagnostics, was implemented to detect anti-microbial effects of wooden discs and filter paper discs containing methanol extracts of different wood parts. The results showed that the bark of larch had an inhibitory effect on Staphylococcus aureus, and the heart wood of pine showed a significant anti-microbial effect on the gram-positive bacteria tested (Staphylococcus aureus, Enterococcus faecium, and Bacillus subtilis. These results were confirmed by using methanol-extracts. An anti-microbial activity against Pseudomonas aeruginosa was not found. Anti-bacterial effects of other parts of larch wood and of pine sapwood were also not found. The results of this study showed for the first time that certain parts of wood contain compounds that directly reduce microbial growth. These data are a further demonstration of the positive effects of specific wood species and could promote the usage of wood in hygienically sensitive areas.

  6. Application of a microalgal slurry to soil stimulates heterotrophic activity and promotes bacterial growth.

    Science.gov (United States)

    Marks, Evan A N; Miñón, Jorge; Pascual, Ana; Montero, Olimpio; Navas, Luis Manuel; Rad, Carlos

    2017-12-15

    Active microalgae biomass from wastewater treatment may be given added value as a biofertilizer, but little is known about how this may affect soil nutrient dynamics and biology. If the goal is to recycle waste nutrients and matter, live algae applied in a liquid slurry to soil may add both organic carbon and nutrients while providing other benefits such as biological carbon fixation. However, the potential persistence of unicellular green algae after such an application is not known, nor the influence of their photosynthetic activity on soil organic carbon - the aim of the present study was to probe these basic questions. In a controlled laboratory microcosm experiment, suspensions of Chlorella sp. microalga culture and sterile filtrates were applied to an agricultural soil and incubated for 42days, whereas the effect of darkness was also tested to understand the importance of photosynthetic activity of the algae. Autotrophic microorganism development was 3.5 times higher in treatments with algae application as measured by chlorophyll pigment concentration. Against expectations that increased photosynthetic activity would decrease the CO2-C flux, the algal suspension with a photoperiod significantly increased soil respiration compared to culture filtrates without algal cells, with accumulated quantities of 1.8 and 0.7gCO2-Cm(-2), respectively. Also, phospholipid fatty acid (PLFA) analyses showed that the suspension accelerated the development of a stable community of eukaryotic and prokaryotic microorganisms in the soil surface, whereas bacterial PLFA biomarkers were significantly associated with eukaryote biomarkers on the study level. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. 16 CFR 1031.5 - Criteria for Commission involvement in voluntary standards activities.

    Science.gov (United States)

    2010-01-01

    ... Commission involvement in the development of voluntary safety standards for consumer products: (a) The... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Criteria for Commission involvement in voluntary standards activities. 1031.5 Section 1031.5 Commercial Practices CONSUMER PRODUCT...

  8. Autonomous motivation: involvement in physical activity, and perceived sport competence: structural and mediator models.

    Science.gov (United States)

    Bagøien, Tor Egil; Halvari, Hallgeir

    2005-02-01

    Students in upper secondary school (N = 231, M = 16.6 yr., SD = 1.6) were tested on involvement in physical activity, perceived sport competence, using the Perceived Competence Scale of Harter, and motivational regulation on the Self-regulation Questionnaire of Ryan and Connell. Correlations were positive among involvement in physical activity, autonomous motivation, and perceived sport competence. A hypothetical model indicated that autonomous motivation mediates the relation between perceived sport competence and involvement in physical activity. Although LISREL analysis supported this mediation, the best model fit of the data supported a structural model with involvement in physical activity (R2 = .63) to mediate between autonomous motivation and perceived competence (R2 = .47). Results are interpreted and discussed in terms of self-determination theory.

  9. 78 FR 57818 - Commission Participation and Commission Employee Involvement in Voluntary Standards Activities

    Science.gov (United States)

    2013-09-20

    ... From the Federal Register Online via the Government Publishing Office CONSUMER PRODUCT SAFETY COMMISSION 16 CFR Part 1031 Commission Participation and Commission Employee Involvement in Voluntary Standards Activities AGENCY: Consumer Product Safety Commission. ACTION: Notice of proposed...

  10. In vitro characterization of the anti-bacterial activity of SQ109 against Helicobacter pylori.

    Directory of Open Access Journals (Sweden)

    Morris O Makobongo

    Full Text Available The most evident challenge to treatment of Helicobacter pylori, a bacterium responsible for gastritis, peptic ulcers and gastric cancer, is the increasing rate of resistance to all currently used therapeutic antibiotics. Thus, the development of novel therapies is urgently required. N-geranyl-N'-(2-adamantyl ethane-1, 2-diamine (SQ109 is an ethylene diamine-based antitubercular drug that is currently in clinical trials for the treatment of tuberculosis (TB. Previous pharmacokinetic studies of SQ109 revealed that persistently high concentrations of SQ109 remain in the stomach 4 hours post oral administration in rats. This finding, combined with the need for new anti-Helicobacter therapies, prompted us to define the in vitro efficacy of SQ109 against H. pylori. Liquid broth micro-dilution was used for susceptibility studies to determine the antimicrobial activity of SQ109 against a total of 6 laboratory strains and 20 clinical isolates of H. pylori; the clinical isolates included a multi-drug resistant strain. All strains tested were susceptible to SQ109 with MIC and MBC ranges of 6-10 µM and 50-60 µM, respectively. SQ109 killing kinetics were concentration- and time-dependent. SQ109 killed H. pylori in 8-10 h at 140 µM (2MBCs or 4-6 h at 200 µM (~3MBCs. Importantly, though the kinetics of killing were altered, SQ109 retained potent bactericidal activity against H. pylori at low pH. Additionally, SQ109 demonstrated robust thermal stability and was effective at killing slow growing or static bacteria. In fact, pretreatment of cultures with a bacteriostatic concentration of chloramphenicol (Cm synergized the effects of typically bacteriostatic concentrations of SQ109 to the level of five-logs of bacterial killing. A molar-to-molar comparison of the efficacy of SQ109 as compared to metronidazole (MTZ, amoxicillin (AMX, rifampicin (RIF and clarithromycin (CLR, revealed that SQ109 was superior to MTZ, AMX and RIF but not to CLR. Finally, the

  11. Health benefits of serious involvement in leisure activities among older Korean adults

    Science.gov (United States)

    Kim, Junhyoung; Yamada, Naoko; Heo, Jinmoo; Han, Areum

    2014-01-01

    The existing literature suggests that serious engagement in leisure activities leads to happiness, life satisfaction, and successful aging among older adults. This qualitative study was used to examine the benefits of serious involvement in leisure activities among older Korean adults who were members of a sports club. Using an analytic data analysis, we identified three main themes associated with the benefits of serious engagement in leisure activities: 1) the experience of psychological benefits, 2) the creation of social support, and 3) the enhancement of physical health. These themes indicate that, through serious involvement in certain physical activities, participants gain various health benefits, which may contribute to successful aging. PMID:25059979

  12. Health benefits of serious involvement in leisure activities among older Korean adults

    Directory of Open Access Journals (Sweden)

    Junhyoung Kim

    2014-07-01

    Full Text Available The existing literature suggests that serious engagement in leisure activities leads to happiness, life satisfaction, and successful aging among older adults. This qualitative study was used to examine the benefits of serious involvement in leisure activities among older Korean adults who were members of a sports club. Using an analytic data analysis, we identified three main themes associated with the benefits of serious engagement in leisure activities: 1 the experience of psychological benefits, 2 the creation of social support, and 3 the enhancement of physical health. These themes indicate that, through serious involvement in certain physical activities, participants gain various health benefits, which may contribute to successful aging.

  13. A mixture of bacterial mechanical lysates is more efficient than single strain lysate and of bacterial-derived soluble products for the induction of an activating phenotype in human dendritic cells.

    Science.gov (United States)

    Morandi, Barbara; Agazzi, Alessia; D'Agostino, Antonella; Antonini, Francesca; Costa, Gregorio; Sabatini, Federica; Ferlazzo, Guido; Melioli, Giovanni

    2011-07-01

    Dendritic cells (DCs), following an optimal maturation, are able to drive an efficient immune-response. For this, both co-stimulatory molecules (CD80 and CD86), activation molecules (CD83) and peptide presenting molecules (HLA) are over-expressed. The in vitro treatment of immature DC with fragments of bacterial strains, obtained by using a mechanical lysis as well as with bacterial-derived molecules (such as lipopolysaccharide and protido-glycan), induced the maturation of DCs and the secretion of a panel of cytokines and chemokines. Of note, ex vivo treated circulating DCs and plasmacytoid DCs were also activated by these bacterial bodies. However, while the particulate fraction of single bacterial strains or soluble bacterial-derived molecules induced a sub-optimal maturation (as evaluated by the expression of an activating phenotype on DCs and the amount of cytokine secretion), the addition of the mixture of the particulate fractions of the different bacterial strains was able to mediate an optimal maturation. These results were also confirmed by using the secretion of both cytokines and chemokines as markers of DC activation. All these findings suggest that the particulate fraction of bacterial lysate mixtures, because of their ability to interact with different surface structures, might be exploited not only as an immunogen, but also as an adjuvant treatment to boost an immune-response to poorly "antigenic" proteins, such as cancer antigens or allergens.

  14. Antibacterial and antifouling activities of chitosan/TiO2/Ag NPs nanocomposite films against packaged drinking water bacterial isolates.

    Science.gov (United States)

    Natarajan, Saravanan; Bhuvaneshwari, M; Lakshmi, D Shanthana; Mrudula, P; Chandrasekaran, N; Mukherjee, Amitava

    2016-10-01

    TiO2 and Ag NPs are widely used as antibacterial agents against many bacterial pathogens. Chitosan (polymer) itself acts as a strong antibacterial agent. Hence, chitosan/TiO2/Ag NPs incorporated nanocomposite film was prepared against packed drinking water bacterial strains. A concentration-dependent increase in the reduction of cell viability was observed in all the isolates under UV-C and dark exposure conditions. The bacteria consortium showed greater resistance against antibacterial effects of chitosan/TiO2/Ag nanocomposite as compared to single isolates. Glycocalyx test and mass assessment conclude the effective antibacterial activity by inhibiting bacterial adhesion on the film surface. The release of LDH and generation of ROS act as the predominant antibacterial mechanism induced by TiO2/Ag NPs. Surface characterization of chitosan/TiO2/Ag nanocomposite was studied by FTIR and XRD analyses and SEM analysis after interaction with the bacteria.

  15. High prevalence of bacterial spore-formers active against mosquito larvae in temporary monsoon flooded sites in Orissa, India.

    Science.gov (United States)

    Rout, Regalin; Raina, Vishakha; Suar, Mrutyunjay; Luethy, Peter

    2011-06-01

    Different ecosystems were probed in the vicinity of the city of Bhubaneswar in the Indian state of Orissa for the presence of bacterial spore-formers with activity against mosquito larvae. The most productive sites were places that were flooded during the monsoon season, including roadside ditches and shorelines of ponds. Among 630 isolates screened, 44 (7%) showed larvicidal activity against larvae of Aedes aegypti. The specific activity of the bacterial spore-formers varied greatly. Isolates were found with specific activities superior to the Bacillus thuringiensis israelensis reference strain of the Pasteur Institute. All mosquitocidal strains produced crystal proteins, and based on the biochemical analyses could be classified into the species B. thuringiensis. Such strains possess the potential for the development of new microbial products for mosquito control in India.

  16. Protective Activity of the Mixtures of Pine Oil and Copper Hydroxide against Bacterial Spot and Anthracnose on Red Pepper

    Directory of Open Access Journals (Sweden)

    Jae-Woo Soh

    2014-09-01

    Full Text Available This research was performed to examine the protective activities of the mixtures of pine oil and copper hydroxide against bacterial spot and anthracnose on pepper plants. As for bacterial spot, the treatment of pine oil alone displayed high disease incidence (59.6% and low protective effect (28.9%. In comparison, the treatments of mixtures and copper hydroxide alone showed protective activities of 66.8-76.1%. The mixture of pine oil and copper hydroxide (4:1 suppressed the most effectively bacterial spot on pepper. On the other hand, the mixture of pine oil and copper hydroxide (4:1 also showed the strongest protective effect against pepper anthracnose among the 4 treatments tested; its disease incidence and disease control value were 49.8% and 41.7%, respectively. The other treatments showed low protective activities with control values of 7.4-17.1%. These results suggested that the mixture of pine oil and copper hydroxide (4:1 can be used for the environmental-friendly disease control of bacterial spot and anthracnose on pepper.

  17. Highly effective bacterial agents against Cimbex quadrimaculatus (Hymenoptera: Cimbicidae): isolation of bacteria and their insecticidal activities.

    Science.gov (United States)

    Cakici, Filiz Ozkan; Ozgen, İnanc; Bolu, Halil; Erbas, Zeynep; Demirbağ, Zihni; Demir, İsmail

    2015-01-01

    Cimbex quadrimaculatus (Hymenoptera: Cimbicidae) is one of the serious pests of almonds in Turkey and worldwide. Since there is no effective control application against this pest, it has been a serious problem up to now. Therefore, we aimed to find an effective bacterium that can be utilized as a biocontrol agent against C. quadrimaculatus in pest management. We isolated seven bacteria from dead and live C. quadrimaculatus larvae, and evaluated the larvicidal potency of all isolates on the respective pest. Based on the morphological, physiological, biochemical and molecular properties (partial sequence of 16S rRNA gene), the isolates were identified to be Bacillus safensis (CQ1), Bacillus subtilis (CQ2), Bacillus tequilensis (CQ3), Enterobacter sp. (CQ4), Kurthia gibsonii (CQ5), Staphylococcus sp. (CQ6) and Staphylococcus sciuri (CQ7). The results of the larvicidal activities of these isolates indicated that the mortality value obtained from all treatments changed from 58 to 100 %, and reached 100 % with B. safensis (CQ1) and B. subtilis (CQ2) on the 3rd instar larvae within 10 days of application of 1.89 × 10(9) cfu/mL bacterial concentration at 25 °C under laboratory conditions. Findings from this study indicate that these isolates appear to be a promising biocontrol agent for C. quadrimaculatus.

  18. Disinfectant and antibiotic activities: a comparative analysis in Brazilian hospital bacterial isolates

    Directory of Open Access Journals (Sweden)

    Guimarães Márcia Aparecida

    2000-01-01

    Full Text Available Nosocomial infections are an important cause of morbidity and mortality all over the world. It has been shown that appropriate environmental hygienic and disinfection practices can be very helpful to hospital infection control. The purpose of this study was to evaluate the bactericidal activity of some disinfectants against antibiotic-susceptible and antibiotic-resistant hospital bacterial isolates. The susceptibility of 27 clinical isolates to disinfectants and antibiotics was determined by the Association of Official Analytical Chemist?s (AOAC Use-Dilution method and by the Kirby-Bauer method, respectively. All strains tested were susceptible to sodium hypochlorite, glutaraldehyde and to the association quaternary ammonium - formaldehyde - ethyl alcohol disinfectants. However, the susceptibility of strains to phenol and to one quaternary ammonium compound was variable. Among twenty-one antibiotic-multiresistant strains (methicillin-resistant staphylococci, Enterococcus spp, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus mirabilis, Enterobacter cloacae, Serratia marcescens and Escherichia coli eleven (52% and eight (38% strains were resistant to the quaternary ammonium and phenol compounds, respectively. Among six isolates that demonstrated susceptibility to antibiotics (staphylococci, Enterococcus spp, P. mirabilis, E. cloacae and E. coli two strains (33% showed resistance to these disinfectants. The results demonstrated the lack of correlation between antibiotic-susceptibility and susceptibility to disinfectants in hospital strains.

  19. Antimicrobial activity of heterotrophic bacterial communities from the marine sponge Erylus discophorus (Astrophorida, Geodiidae.

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    Ana Patrícia Graça

    Full Text Available Heterotrophic bacteria associated with two specimens of the marine sponge Erylus discophorus were screened for their capacity to produce bioactive compounds against a panel of human pathogens (Staphylococcus aureus wild type and methicillin-resistant S. aureus (MRSA, Bacillus subtilis, Pseudomonas aeruginosa, Acinetobacter baumanii, Candida albicans and Aspergillus fumigatus, fish pathogen (Aliivibrio fischeri and environmentally relevant bacteria (Vibrio harveyi. The sponges were collected in Berlengas Islands, Portugal. Of the 212 isolated heterotrophic bacteria belonging to Alpha- and Gammaproteobacteria, Actinobacteria and Firmicutes, 31% produced antimicrobial metabolites. Bioactivity was found against both Gram positive and Gram negative and clinically and environmentally relevant target microorganisms. Bioactivity was found mainly against B. subtilis and some bioactivity against S. aureus MRSA, V. harveyi and A. fisheri. No antifungal activity was detected. The three most bioactive genera were Pseudovibrio (47.0%, Vibrio (22.7% and Bacillus (7.6%. Other less bioactive genera were Labrenzia, Acinetobacter, Microbulbifer, Pseudomonas, Gordonia, Microbacterium, Micrococcus and Mycobacterium, Paenibacillus and Staphylococcus. The search of polyketide I synthases (PKS-I and nonribosomal peptide synthetases (NRPSs genes in 59 of the bioactive bacteria suggested the presence of PKS-I in 12 strains, NRPS in 3 strains and both genes in 3 strains. Our results show the potential of the bacterial community associated with Erylus discophorus sponges as producers of bioactive compounds.

  20. Strategies for the recovery of active proteins through refolding of bacterial inclusion body proteins

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    Rinas Ursula

    2004-09-01

    Full Text Available Abstract Recent advances in generating active proteins through refolding of bacterial inclusion body proteins are summarized in conjunction with a short overview on inclusion body isolation and solubilization procedures. In particular, the pros and cons of well-established robust refolding techniques such as direct dilution as well as less common ones such as diafiltration or chromatographic processes including size exclusion chromatography, matrix- or affinity-based techniques and hydrophobic interaction chromatography are discussed. Moreover, the effect of physical variables (temperature and pressure as well as the presence of buffer additives on the refolding process is elucidated. In particular, the impact of protein stabilizing or destabilizing low- and high-molecular weight additives as well as micellar and liposomal systems on protein refolding is illustrated. Also, techniques mimicking the principles encountered during in vivo folding such as processes based on natural and artificial chaperones and propeptide-assisted protein refolding are presented. Moreover, the special requirements for the generation of disulfide bonded proteins and the specific problems and solutions, which arise during process integration are discussed. Finally, the different strategies are examined regarding their applicability for large-scale production processes or high-throughput screening procedures.

  1. Efficient production of active chicken avidin using a bacterial signal peptide in Escherichia coli.

    Science.gov (United States)

    Hytönen, Vesa P; Laitinen, Olli H; Airenne, Tomi T; Kidron, Heidi; Meltola, Niko J; Porkka, Eevaleena J; Hörhä, Jarno; Paldanius, Tiina; Määttä, Juha A E; Nordlund, Henri R; Johnson, Mark S; Salminen, Tiina A; Airenne, Kari J; Ylä-Herttuala, Seppo; Kulomaa, Markku S

    2004-12-01

    Chicken avidin is a highly popular tool with countless applications in the life sciences. In the present study, an efficient method for producing avidin protein in the periplasmic space of Escherichia coli in the active form is described. Avidin was produced by replacing the native signal sequence of the protein with a bacterial OmpA secretion signal. The yield after a single 2-iminobiotin-agarose affinity purification step was approx. 10 mg/l of virtually pure avidin. Purified avidin had 3.7 free biotin-binding sites per tetramer and showed the same biotin-binding affinity and thermal stability as egg-white avidin. Avidin crystallized under various conditions, which will enable X-ray crystallographic studies. Avidin produced in E. coli lacks the carbohydrate chains of chicken avidin and the absence of glycosylation should decrease the non-specific binding that avidin exhibits towards many materials [Rosebrough and Hartley (1996) J. Nucl. Med. 37, 1380-1384]. The present method provides a feasible and inexpensive alternative for the production of recombinant avidin, avidin mutants and avidin fusion proteins for novel avidin-biotin technology applications.

  2. Bacterial capsular polysaccharide prevents the onset of asthma through T-cell activation.

    Science.gov (United States)

    Johnson, Jenny L; Jones, Mark B; Cobb, Brian A

    2015-04-01

    Over the last four decades, increases in the incidence of immune-mediated diseases in the Western world have been linked to changes in microbial exposure. It is becoming increasingly clear that the normal microbiota in the gut can profoundly alter susceptibility to a wide range of diseases, such as asthma, in which immune homeostasis is disrupted, yet the mechanisms governing this microbial influence remains poorly defined. In this study, we show that gastrointestinal exposure to PSA, a capsular polysaccharide derived from the commensal bacterium Bacteroides fragilis, significantly limits susceptibility to the induction of experimental asthma. We report that direct treatment of mice with PSA generates protection from asthma, and this effect can be given to a naïve recipient by adoptive transfer of CD4(+) T cells from PSA-exposed mice. Remarkably, we found that these PSA-induced T cells are not canonical FoxP3(+) regulatory T cells, but that they potently inhibit both Th1 and Th2 models of asthma in an IL-10-dependent fashion. These findings reveal that bacterial polysaccharides link the microbiota with the peripheral immune system by activating CD4(+)Foxp3(-) T cells upon exposure in the gut, and they facilitate resistance to unnecessary inflammatory responses via the production of IL-10. © The Author 2014. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. Prevalence of bacterial vaginosis in sexually active females in Chhattisgarh Institute of Medical Sciences, Bilaspur, Chhattisgarh

    Directory of Open Access Journals (Sweden)

    Sangeeta Raman Jogi

    2015-08-01

    Full Text Available Background: To know the prevalence of bacterial vaginosis (BV in sexually active females presenting with the complaints of Vaginal discharge to the outpatient department. BV also called as non-specific vaginitis, develops when the normally predominant peroxides producing lactobacillus species in the vagina are replaced by mixed predominantly anaerobic flora consisting of Gardinerella vaginalis, Mycoplasm hominis, Mobilunceus species, Bacteroids species, Prevotela Species, Peptostreptococcus Species, Fusobacterium Species and Porphyromonus Species. Methods: Three hundred females attending the OPD with the complaints of vaginal discharge were studied. Diagnosis of BV were made according to Amsle's clinical criteria and Nugents criteria for evaluating Gram stain vaginal smear. The results were compared with the data available from the previous studies. Results: Out of 300 patients 122 (40.66% were suffering from BV. 90 (73.33% patients were having pH between 5-6.9. Among pregnant women 9.83% found positive. IUCD users 19 (29.68% are found suffering from BV. Out of 33 VDRL positive patients 19 (57.51% were positive with BV. Conclusions: The prevalence of BV is on higher side of the available data. There is an association between IUCD use and occurrence of BV. [Int J Reprod Contracept Obstet Gynecol 2015; 4(4.000: 963-967

  4. Reactive radical-driven bacterial inactivation by hydrogen-peroxide-enhanced plasma-activated-water

    Science.gov (United States)

    Wu, Songjie; Zhang, Qian; Ma, Ruonan; Yu, Shuang; Wang, Kaile; Zhang, Jue; Fang, Jing

    2017-08-01

    The combined effects of plasma activated water (PAW) and hydrogen peroxide (H2O2), PAW/HP, in sterilization were investigated in this study. To assess the synergistic effects of PAW/HP, S. aureus was selected as the test microorganism to determine the inactivation efficacy. Also, the DNA/RNA and proteins released by the bacterial suspensions under different conditions were examined to confirm membrane integrity. Additionally, the intracellular pH (pHi) of S. aureus was measured in our study. Electron spin resonance spectroscopy (ESR) was employed to identify the presence of radicals. Finally, the oxidation reduction potential (ORP), conductivity and pH were measured. Our results revealed that the inactivation efficacy of PAW/HP is much greater than that of PAW, while increased H2O2 concentration result in higher inactivation potential. More importantly, as compared with PAW, the much stronger intensity ESR signals and higher ORP in PAW/HP suggests that the inactivation mechanism of the synergistic effects of PAW/HP: more reactive oxygen species (ROS) and reactive nitrogen species (RNS), especially OH and NO radicals, are generated in PAW combined with H2O2 resulting in more deaths of the bacteria.

  5. Expanded insecticide catabolic activity gained by a single nucleotide substitution in a bacterial carbamate hydrolase gene.

    Science.gov (United States)

    Öztürk, Başak; Ghequire, Maarten; Nguyen, Thi Phi Oanh; De Mot, René; Wattiez, Ruddy; Springael, Dirk

    2016-12-01

    Carbofuran-mineralizing strain Novosphingobium sp. KN65.2 produces the CfdJ enzyme that converts the N-methylcarbamate insecticide to carbofuran phenol. Purified CfdJ shows a remarkably low KM towards carbofuran. Together with the carbaryl hydrolase CehA of Rhizobium sp. strain AC100, CfdJ represents a new protein family with several uncharacterized bacterial members outside the proteobacteria. Although both enzymes differ by only four amino acids, CehA does not recognize carbofuran as a substrate whereas CfdJ also hydrolyzes carbaryl. None of the CfdJ amino acids that differ from CehA were shown to be silent regarding carbofuran hydrolytic activity but one particular amino acid substitution, i.e., L152 to F152, proved crucial. CfdJ is more efficient in degrading methylcarbamate pesticides with an aromatic side chain whereas CehA is more efficient in degrading the oxime carbamate nematicide oxamyl. The presence of common flanking sequences suggest that the cfdJ gene is located on a remnant of the mobile genetic element Tnceh carrying cehA. Our results suggest that these enzymes can be acquired through horizontal gene transfer and can evolve to degrade new carbamate substrates by limited amino acid substitutions. We demonstrate that a carbaryl hydrolase can gain the additional capacity to degrade carbofuran by a single nucleotide transversion. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  6. A two-subunit bacterial sigma-factor activates transcription in Bacillus subtilis.

    Science.gov (United States)

    MacLellan, Shawn R; Guariglia-Oropeza, Veronica; Gaballa, Ahmed; Helmann, John D

    2009-12-15

    The sigma-like factor YvrI and coregulator YvrHa activate transcription from a small set of conserved promoters in Bacillus subtilis. We report here that these two proteins independently contribute sigma-region 2 and sigma-region 4 functions to a holoenzyme-promoter DNA complex. YvrI binds RNA polymerase (RNAP) through a region 4 interaction with the beta-subunit flap domain and mediates specific promoter recognition but cannot initiate DNA melting at the -10 promoter element. Conversely, YvrHa possesses sequence similarity to a conserved core-binding motif in sigma-region 2 and binds to the N-terminal coiled-coil element in the RNAP beta'-subunit previously implicated in interaction with region 2 of sigma-factors. YvrHa plays an essential role in stabilizing the open complex and interacts specifically with the N-terminus of YvrI. Based on these results, we propose that YvrHa is situated in the transcription complex proximal to the -10 element of the promoter, whereas YvrI is responsible for -35 region recognition. This system presents an unusual example of a two-subunit bacterial sigma-factor.

  7. Regulatory cascade and biological activity of Beauveria bassiana oosporein that limits bacterial growth after host death.

    Science.gov (United States)

    Fan, Yanhua; Liu, Xi; Keyhani, Nemat O; Tang, Guirong; Pei, Yan; Zhang, Wenwen; Tong, Sheng

    2017-02-28

    The regulatory network and biological functions of the fungal secondary metabolite oosporein have remained obscure. Beauveria bassiana has evolved the ability to parasitize insects and outcompete microbial challengers for assimilation of host nutrients. A novel zinc finger transcription factor, BbSmr1 (B. bassiana secondary metabolite regulator 1), was identified in a screen for oosporein overproduction. Deletion of Bbsmr1 resulted in up-regulation of the oosporein biosynthetic gene cluster (OpS genes) and constitutive oosporein production. Oosporein production was abolished in double mutants of Bbsmr1 and a second transcription factor, OpS3, within the oosporein gene cluster (ΔBbsmr1ΔOpS3), indicating that BbSmr1 acts as a negative regulator of OpS3 expression. Real-time quantitative PCR and a GFP promoter fusion construct of OpS1, the oosporein polyketide synthase, indicated that OpS1 is expressed mainly in insect cadavers at 24-48 h after death. Bacterial colony analysis in B. bassiana-infected insect hosts revealed increasing counts until host death, with a dramatic decrease (∼90%) after death that correlated with oosporein production. In vitro studies verified the inhibitory activity of oosporein against bacteria derived from insect cadavers. These results suggest that oosporein acts as an antimicrobial compound to limit microbial competition on B. bassiana-killed hosts, allowing the fungus to maximally use host nutrients to grow and sporulate on infected cadavers.

  8. Antimicrobial Activity of Monoramnholipids Produced by Bacterial Strains Isolated from the Ross Sea (Antarctica

    Directory of Open Access Journals (Sweden)

    Pietro Tedesco

    2016-04-01

    Full Text Available Microorganisms living in extreme environments represent a huge reservoir of novel antimicrobial compounds and possibly of novel chemical families. Antarctica is one of the most extraordinary places on Earth and exhibits many distinctive features. Antarctic microorganisms are well known producers of valuable secondary metabolites. Specifically, several Antarctic strains have been reported to inhibit opportunistic human pathogens strains belonging to Burkholderia cepacia complex (Bcc. Herein, we applied a biodiscovery pipeline for the identification of anti-Bcc compounds. Antarctic sub-sea sediments were collected from the Ross Sea, and used to isolate 25 microorganisms, which were phylogenetically affiliated to three bacterial genera (Psychrobacter, Arthrobacter, and Pseudomonas via sequencing and analysis of 16S rRNA genes. They were then subjected to a primary cell-based screening to determine their bioactivity against Bcc strains. Positive isolates were used to produce crude extracts from microbial spent culture media, to perform the secondary screening. Strain Pseudomonas BNT1 was then selected for bioassay-guided purification employing SPE and HPLC. Finally, LC-MS and NMR structurally resolved the purified bioactive compounds. With this strategy, we achieved the isolation of three rhamnolipids, two of which were new, endowed with high (MIC < 1 μg/mL and unreported antimicrobial activity against Bcc strains.

  9. Antimicrobial Activity of Monoramnholipids Produced by Bacterial Strains Isolated from the Ross Sea (Antarctica) †

    Science.gov (United States)

    Tedesco, Pietro; Maida, Isabel; Palma Esposito, Fortunato; Tortorella, Emiliana; Subko, Karolina; Ezeofor, Chidinma Christiana; Zhang, Ying; Tabudravu, Jioji; Jaspars, Marcel; Fani, Renato; de Pascale, Donatella

    2016-01-01

    Microorganisms living in extreme environments represent a huge reservoir of novel antimicrobial compounds and possibly of novel chemical families. Antarctica is one of the most extraordinary places on Earth and exhibits many distinctive features. Antarctic microorganisms are well known producers of valuable secondary metabolites. Specifically, several Antarctic strains have been reported to inhibit opportunistic human pathogens strains belonging to Burkholderia cepacia complex (Bcc). Herein, we applied a biodiscovery pipeline for the identification of anti-Bcc compounds. Antarctic sub-sea sediments were collected from the Ross Sea, and used to isolate 25 microorganisms, which were phylogenetically affiliated to three bacterial genera (Psychrobacter, Arthrobacter, and Pseudomonas) via sequencing and analysis of 16S rRNA genes. They were then subjected to a primary cell-based screening to determine their bioactivity against Bcc strains. Positive isolates were used to produce crude extracts from microbial spent culture media, to perform the secondary screening. Strain Pseudomonas BNT1 was then selected for bioassay-guided purification employing SPE and HPLC. Finally, LC-MS and NMR structurally resolved the purified bioactive compounds. With this strategy, we achieved the isolation of three rhamnolipids, two of which were new, endowed with high (MIC < 1 μg/mL) and unreported antimicrobial activity against Bcc strains. PMID:27128927

  10. Bacterial lipases

    NARCIS (Netherlands)

    Jaeger, Karl-Erich; Ransac, Stéphane; Dijkstra, Bauke W.; Colson, Charles; Heuvel, Margreet van; Misset, Onno

    1994-01-01

    Many different bacterial species produce lipases which hydrolyze esters of glycerol with preferably long-chain fatty acids. They act at the interface generated by a hydrophobic lipid substrate in a hydrophilic aqueous medium. A characteristic property of lipases is called interfacial activation, mea

  11. 40 CFR 13.5 - Claims involving criminal activities or misconduct.

    Science.gov (United States)

    2010-07-01

    ... misconduct. 13.5 Section 13.5 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GENERAL CLAIMS COLLECTION STANDARDS General § 13.5 Claims involving criminal activities or misconduct. (a) The Administrator will refer cases of suspected criminal activity or misconduct to the EPA Office of Inspector...

  12. Middle-Class Parental Involvement in the Summer Activities of Four Elementary Students: A Qualitative Study

    Science.gov (United States)

    Ballard, Iva B.; Chappell, Manya; Johnson, Susan; Ngassam, Marlise DePaul

    2013-01-01

    In this study, we explore middle-class parental involvement in summer activities of four elementary students. Many researchers discuss summer programs initiated by institutions, but fail to explain how parents' availability, experiences, and related criteria affect student summer activities. From our interviews, observations, and artifacts, we…

  13. A Study of Lipscomb University Students' Internet Use and Involvement in Extracurricular Activities

    Science.gov (United States)

    Smith, Samuel Aarron

    2010-01-01

    The purpose of this study was to analyze Lipscomb University students' Internet use and involvement in extracurricular activities. A survey of students at Lipscomb University was conducted. As confirmed by the data the research was able to determine that the type of extracurricular activity a student participates in most often is related to the…

  14. Anti-fungal and anti-bacterial activities of ethanol extracts of selected traditional Chinese medicinal herbs

    Institute of Scientific and Technical Information of China (English)

    Lin Zhang; ngeles Melguizo; Ester Jimnez; Francisca Vicente; Anjaneya S Ravipati; Sundar R Koyyalamudi; Sang Chul Jeong; Narsimha Reddy; John Bartlett; Paul T Smith; Mercedes de la Cruz; Maria Cndida Monteiro

    2013-01-01

    Objective:To evaluate in vitro antimicrobial activities of selected 58 ethno-medicinal plant extracts with a view to assess their therapeutic potential. Methods:A total of 58 traditional Chinese medicinal plants were carefully selected based on the literature review and their traditional use. The antimicrobial activities of ethanol extracts of these medicinal plants were tested against fungi (Aspergillus fumigatus), yeast (Candida albicans), gram-negative (Acinetobacter baumannii and Pseudomonas aeruginosa) and gram-positive bacteria (Staphylococcus aureus). The activities were tested at three different concentrations of 1.00, 0.10 and 0.01 mg/mL. The data was analysed using Gene data Screener program. Results: The measured antimicrobial activities indicated that out of the 58 plant extracts, 15 extracts showed anti-fungal activity and 23 extracts exhibited anti-bacterial activity. Eight plant extracts have exhibited both anti-bacterial and anti-fungal activities. For instance, Eucommia ulmoides, Polygonum cuspidatum, Poria cocos and Uncaria rhyncophylla showed activity against both bacterial and fungal strains, indicating their broad spectrum of activity. Conclusions: The results revealed that the ethanol extracts of 30 plants out of the selected 58 possess significant antimicrobial activities. It is interesting to note that the findings from the current study are consistent with the traditional use. A clear correlation has also been found between the antimicrobial activity and the flavonoid content of the plant extracts which is in agreement with the literature. Hence, the results presented here can be used to guide the selection of potential plant species for the isolation and structure elucidation of novel antimicrobial compounds in order to establish the structure-activity relationship. This in turn is expected to lead the way to the discovery of novel antimicrobial agents for therapeutic use.

  15. An oxidative burst and its attenuation by bacterial peroxidase activity is required for optimal establishment of the Arachis hypogaea-Bradyrhizobium sp. symbiosis.

    Science.gov (United States)

    Muñoz, V; Ibáñez, F; Figueredo, M S; Fabra, A

    2016-07-01

    The main purpose of this study was to determine whether the Arachis hypogaea L. root oxidative burst, produced at early stages of its symbiotic interaction with Bradyrhizobium sp. SEMIA 6144, and the bacterial antioxidant system are required for the successful development of this interaction. Pharmacological approaches were used to reduce both plant oxidative burst and bacterial peroxidase enzyme activity. In plants whose H2 O2 levels were decreased, a low nodule number, a reduction in the proportion of red nodules (%) and an increase in the bacteroid density were found. The symbiotic phenotype of plants inoculated with a Bradyrhizobium sp. SEMIA 6144 culture showing decreased peroxidase activity was also affected, since the biomass production, nodule number and percentage of red nodules in these plants were lower than in plants inoculated with Bradyrhizobium sp. control cultures. We demonstrated for the first time that the oxidative burst triggered at the early events of the symbiotic interaction in peanut, is a prerequisite for the efficient development of root nodules, and that the antioxidant system of bradyrhizobial peanut symbionts, particularly the activity of peroxidases, is counteracting this oxidative burst for the successful establishment of the symbiosis. Our results provide new insights into the mechanisms involved in the development of the symbiotic interaction established in A. hypogaea L. a legume infected in an intercellular way. © 2016 The Society for Applied Microbiology.

  16. Anti-inflammatory, anti-bacterial, and cytotoxic activity of fibrous clays.

    Science.gov (United States)

    Cervini-Silva, Javiera; Nieto-Camacho, Antonio-; Ramírez-Apan, María Teresa; Gómez-Vidales, Virginia; Palacios, Eduardo; Montoya, Ascención; Ronquillo de Jesús, Elba

    2015-05-01

    Produced worldwide at 1.2m tons per year, fibrous clays are used in the production of pet litter, animal feed stuff to roof parcels, construction and rheological additives, and other applications needing to replace long-fiber length asbestos. To the authors' knowledge, however, information on the beneficial effects of fibrous clays on health remains scarce. This paper reports on the anti-inflammatory, anti-bacterial, and cytotoxic activity by sepiolite (Vallecas, Spain) and palygorskite (Torrejon El Rubio, Spain). The anti-inflammatory activity was determined using the 12-O-tetradecanoylphorbol-13-acetate (TPA) and myeloperoxidase (MPO) methods. Histological cuts were obtained for quantifying leukocytes found in the epidermis. Palygorkite and sepiolite caused edema inhibition and migration of neutrophils ca. 68.64 and 45.54%, and 80 and 65%, respectively. Fibrous clays yielded high rates of infiltration, explained by cleavage of polysomes and exposure of silanol groups. Also, fibrous clays showed high inhibition of myeloperoxidase contents shortly after exposure, but decreased sharply afterwards. In contrast, tubular clays caused an increasing inhibition of myeloperoxidase with time. Thus, clay structure restricted the kinetics and mechanism of myeloperoxidase inhibition. Fibrous clays were screened in vitro against human cancer cell lines. Cytotoxicity was determined using the protein-binding dye sulforhodamine B (SRB). Exposing cancer human cells to sepiolite or palygorskite showed growth inhibition varying with cell line. This study shows that fibrous clays served as an effective anti-inflammatory, limited by chemical transfer and cellular-level signals responding exclusively to an early exposure to clay, and cell viability decreasing significantly only after exposure to high concentrations of sepiolite.

  17. Inhibition of Bacterial Toxin Activity by the Nuclear Stain, DRAQ5™.

    Science.gov (United States)

    Webb, Joshua N; Koufos, Evan; Brown, Angela C

    2016-08-01

    The repeats-in-toxin family of toxins includes proteins produced by Gram negative bacteria such as Escherichia coli (α-hemolysin), Bordetella pertussis (adenylate cyclase toxin), and Aggregatibacter actinomycetemcomitans (LtxA), which contribute to the pathogenesis of these organisms by killing host cells. In the case of LtxA produced by A. actinomycetemcomitans, white blood cells are targeted, allowing the bacteria to avoid clearance by the host immune system. In its association with target cells, LtxA binds to a receptor, lymphocyte function-associated antigen-1, as well as membrane lipids and cholesterol, before being internalized via a lysosomal-mediated pathway. The motivation for this project comes from our discovery that DRAQ5™, a membrane-permeable nuclear stain, prevents the internalization of LtxA in a Jurkat T cell line. We hypothesized that DRAQ5™, in crossing the plasma membrane, alters the properties of the membrane to inhibit LtxA internalization. To investigate how DRAQ5™ interacts with the lipid membrane to prevent LtxA internalization, we used studied DRAQ5™-mediated membrane changes in model membranes using a variety of techniques, including differential scanning calorimetry and fluorescence spectroscopy. Our results suggest that DRAQ5™ inhibits the activity of LtxA by decreasing the fluidity of the cellular lipid membrane, which decreases LtxA binding. These results present an interesting possible anti-virulence strategy; by altering bacterial toxin activity by modifying membrane fluidity, it may be possible to inhibit the pathogenicity of A. actinomycetemcomitans.

  18. Oxygen Affects Gut Bacterial Colonization and Metabolic Activities in a Gnotobiotic Cockroach Model

    Science.gov (United States)

    Tegtmeier, Dorothee; Thompson, Claire L.; Schauer, Christine

    2015-01-01

    The gut microbiota of termites and cockroaches represents complex metabolic networks of many diverse microbial populations. The distinct microenvironmental conditions within the gut and possible interactions among the microorganisms make it essential to investigate how far the metabolic properties of pure cultures reflect their activities in their natural environment. We established the cockroach Shelfordella lateralis as a gnotobiotic model and inoculated germfree nymphs with two bacterial strains isolated from the guts of conventional cockroaches. Fluorescence microscopy revealed that both strains specifically colonized the germfree hindgut. In diassociated cockroaches, the facultatively anaerobic strain EbSL (a new species of Enterobacteriaceae) always outnumbered the obligately anaerobic strain FuSL (a close relative of Fusobacterium varium), irrespective of the sequence of inoculation, which showed that precolonization by facultatively anaerobic bacteria does not necessarily favor colonization by obligate anaerobes. Comparison of the fermentation products of the cultures formed in vitro with those accumulated in situ indicated that the gut environment strongly affected the metabolic activities of both strains. The pure cultures formed the typical products of mixed-acid or butyrate fermentation, whereas the guts of gnotobiotic cockroaches accumulated mostly lactate and acetate. Similar shifts toward more-oxidized products were observed when the pure cultures were exposed to oxygen, which corroborated the strong effects of oxygen on the metabolic fluxes previously observed in termite guts. Oxygen microsensor profiles of the guts of germfree, gnotobiotic, and conventional cockroaches indicated that both gut tissue and microbiota contribute to oxygen consumption and suggest that the oxygen status influences the colonization success. PMID:26637604

  19. Alternative primer sets for PCR detection of genotypes involved in bacterial aerobic BTEX degradation : Distribution of the genes in BTEX degrading isolates and in subsurface soils of a BTEX contaminated industrial site

    NARCIS (Netherlands)

    Hendrickx, B; Junca, H; Vosahlova, J; Lindner, A; Ruegg, [No Value; Bucheli-Witschel, M; Faber, F; Egli, T; Mau, M; Schlomann, M; Brennerova, M; Brenner, [No Value; Pieper, DH; Top, EM; Dejonghe, W; Bastiaens, L; Springael, D

    2006-01-01

    Eight new primer sets were designed for PCR detection of (i) mono-oxygenase and dioxygenase gene sequences involved in initial attack of bacterial aerobic BTEX degradation and of (ii) catechol 2,3-dioxygenase gene sequences responsible for metacleavage of the aromatic ring. The new primer sets allow

  20. Adsorption and oxidation of SO₂in a fixed-bed reactor using activated carbon produced from oxytetracycline bacterial residue and impregnated with copper.

    Science.gov (United States)

    Zhou, Baohua; Yu, Lei; Song, Hanning; Li, Yaqi; Zhang, Peng; Guo, Bin; Duan, Erhong

    2015-02-01

    The SO₂removal ability (including adsorption and oxidation ability) of activated carbon produced from oxytetracycline bacterial residue and impregnated with copper was investigated. The activated carbon produced from oxytetracycline bacterial residue and modified with copper was characterized by x-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy. The effects of the catalysts, SO₂concentration, weight hourly space velocity, and temperature on the SO₂adsorption and oxidation activity were evaluated. Activated carbon produced from oxytetracycline bacterial residue and used as catalyst supports for copper oxide catalysts provided high catalytic activity for the adsorbing and oxidizing of SO₂from flue gases.

  1. Heterotrophic activity, bacterial types and abundance in different ecosystems of the Queen Maud Land

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaiah, N.; Kodagali, J.; Nair, S.; Sheelu, G.; Chandramohan, D.

    Microbiological studies from the marine, limnetic, terrestrial and glacial ecosystems were carried out during the Ninth Indian Expedition (1989-90) to estimate the bacterial numbers, to characterise the generic types and also to estimate the uptake...

  2. Abundance, activity, and diversity of archaeal and bacterial communities in both uncontaminated and highly copper-contaminated marine sediments.

    Science.gov (United States)

    Besaury, Ludovic; Ghiglione, Jean-François; Quillet, Laurent

    2014-04-01

    We analyzed the impact of copper mine tailing discharges on benthic Archaea and Bacteria around the city of Chanaral in northern Chile. Quantitative PCR (Q-PCR) showed that the bacteria dominated the prokaryotic community at both sites, but only the bacteria showed a decrease in abundance in the copper-contaminated site. Q-PCR on reverse transcripts indicated a higher activity of both bacterial and archaeal communities in the contaminated site, suggesting an adaptation of the two communities to copper. This hypothesis was reinforced by the concomitant augmentation of the copper-resistant copA gene coding for a P-type ATP-ase pump in the contaminated site. The metabolically active bacterial community of the contaminated site was dominated by Gammaproteobacteria related to Ectothiorhodospiraceae and Chromatiaceae and by Alphaproteobacteria phylum related to Rhodobacteraceae. The metabolically active archaeal community was dominated by one lineage belonging to unclassified Euryarchaeota and to methanogenic Archaea.

  3. Microbiological analysis of common preservatives used in food items and demonstration of their in vitro anti-bacterial activity

    Directory of Open Access Journals (Sweden)

    Tohora Sultana

    2014-12-01

    Full Text Available Objective: To quantify the microorganisms contaminating the common preservatives used in food as well as to detect their in vitro anti-bacterial traits. Methods: A total of 9 preservatives were subjected to conventional cultural and biochemical methods for microbial enumeration. Anti-bacterial activities were demonstrated through the agar well diffusion method. Results: All samples were found to be contaminated with bacteria up to 105 CFU/g and with the fungal flora within a range of 1 01-1 02 CFU/g. Escherichia coli, Pseudomonas spp. and Staphylococcus spp. were demonstrated in most of the samples. Sodium sulfite and citric acid possessed the strongest anti-bacterial trait against all of the test bacteria. Acetic acid exhibited activity against 6 out of 8 test bacteria while vinegar exhibited the activity against 4 bacteria. Activity of salt was demonstrated only against Listeria spp. and Bacillus spp., while activity of sugar and honey was found only against Escherichia coli and Klebsiella spp., respectively. Conclusions: According to the current investigation, sodium sulfite and citric acid samples were found to be satisfactory preservatives both in terms of microbiological criteria and their antibacterial traits.

  4. Isolation of a gene that is involved in Campylobacter jejuni 81116 cytotoxin activation.

    Science.gov (United States)

    Liu, Kaiyan; Fry, Benjamin N; Coloe, Peter J

    2007-02-01

    Cytotoxin fractions were isolated from Campylobacter jejuni 81116 and semi-purified by size-exclusion liquid chromatography. The fraction showing the strongest toxicity was injected into mice to produce antiserum. The antiserum was used to screen a C. jejuni 81116 cosmid library. Nine genes were identified in overlapping cosmid inserts that induced reactivity with the antiserum. One of these genes showed high similarity to a periplasmic protein of unknown function and its isogenic mutant showed decreased toxicity compared to the C. jejuni 81116 wild type. This gene contains a Gram-negative bacterial RTX toxin-activating protein C signature, which suggests it may play a role in C. jejuni 81116 cytotoxin activation.

  5. EDTA addition enhances bacterial respiration activities and hydrocarbon degradation in bioaugmented and non-bioaugmented oil-contaminated desert soils.

    Science.gov (United States)

    Al Kharusi, Samiha; Abed, Raeid M M; Dobretsov, Sergey

    2016-03-01

    The low number and activity of hydrocarbon-degrading bacteria and the low solubility and availability of hydrocarbons hamper bioremediation of oil-contaminated soils in arid deserts, thus bioremediation treatments that circumvent these limitations are required. We tested the effect of Ethylenediaminetetraacetic acid (EDTA) addition, at different concentrations (i.e. 0.1, 1 and 10 mM), on bacterial respiration and biodegradation of Arabian light oil in bioaugmented (i.e. with the addition of exogenous alkane-degrading consortium) and non-bioaugmented oil-contaminated desert soils. Post-treatment shifts in the soils' bacterial community structure were monitored using MiSeq sequencing. Bacterial respiration, indicated by the amount of evolved CO2, was highest at 10 mM EDTA in bioaugmented and non-bioaugmented soils, reaching an amount of 2.2 ± 0.08 and 1.6 ± 0.02 mg-CO2 g(-1) after 14 days of incubation, respectively. GC-MS revealed that 91.5% of the C14-C30 alkanes were degraded after 42 days when 10 mM EDTA and the bacterial consortium were added together. MiSeq sequencing showed that 78-91% of retrieved sequences in the original soil belonged to Deinococci, Alphaproteobacteria, Gammaproteobacteia and Bacilli. The same bacterial classes were detected in the 10 mM EDTA-treated soils, however with slight differences in their relative abundances. In the bioaugmented soils, only Alcanivorax sp. MH3 and Parvibaculum sp. MH21 from the exogenous bacterial consortium could survive until the end of the experiment. We conclude that the addition of EDTA at appropriate concentrations could facilitate biodegradation processes by increasing hydrocarbon availability to microbes. The addition of exogenous oil-degrading bacteria along with EDTA could serve as an ideal solution for the decontamination of oil-contaminated desert soils.

  6. Impact of titanium dioxide nanoparticles on the bacterial communities of biological activated carbon filter intended for drinking water treatment.

    Science.gov (United States)

    Zhiyuan, Liu; Shuili, Yu; Heedeung, Park; Qingbin, Yuan; Guicai, Liu; Qi, Li

    2016-08-01

    Titanium dioxide nanoparticles (TiO2 NPs) are inevitably present in the aquatic environment owing to their increasing production and use. However, knowledge of the potential effects of TiO2 NPs on the treatment of drinking water is scarce. Herein, the effects of two types of anatase TiO2 NPs (TP1, 25 nm; TP2, 100 nm) on the bacterial community in a biological activated carbon (BAC) filter were investigated via quantitative polymerase chain reaction (Q-PCR) analysis, ATP quantification, and 454 pyrosequencing analysis. Both TP1 and TP2 significantly inhibited the bacterial ATP level (p < 0.01) and induced a decrease in the abundance of bacterial 16S rDNA gene copies at doses of 0.1 and 100 mg L(-1). Simultaneously, the diversity and evenness of the bacterial communities were considerably reduced. The relative abundances of bacteria annotated to OTUs from Nitrospira class and Betaproteobacteria class decreased upon TiO2 NP treatment, whereas those of Bacilli class and Gammaproteobacteria class increased. TiO2 NP size showed a greater effect on the bacterial composition than did the dose based on Bray-Curtis distances. These findings identified negative effects of TiO2 NPs on the bacterial community in the BAC filter. Given the fact that BAC filters are used widely in drinking water treatment plants, these results suggested a potential threat by TiO2 NP to drinking water treatment system.

  7. High inorganic triphosphatase activities in bacteria and mammalian cells: identification of the enzymes involved.

    Directory of Open Access Journals (Sweden)

    Gregory Kohn

    Full Text Available BACKGROUND: We recently characterized a specific inorganic triphosphatase (PPPase from Nitrosomonas europaea. This enzyme belongs to the CYTH superfamily of proteins. Many bacterial members of this family are annotated as predicted adenylate cyclases, because one of the founding members is CyaB adenylate cyclase from A. hydrophila. The aim of the present study is to determine whether other members of the CYTH protein family also have a PPPase activity, if there are PPPase activities in animal tissues and what enzymes are responsible for these activities. METHODOLOGY/PRINCIPAL FINDINGS: Recombinant enzymes were expressed and purified as GST- or His-tagged fusion proteins and the enzyme activities were determined by measuring the release of inorganic phosphate. We show that the hitherto uncharacterized E. coli CYTH protein ygiF is a specific PPPase, but it contributes only marginally to the total PPPase activity in this organism, where the main enzyme responsible for hydrolysis of inorganic triphosphate (PPP(i is inorganic pyrophosphatase. We further show that CyaB hydrolyzes PPP(i but this activity is low compared to its adenylate cyclase activity. Finally we demonstrate a high PPPase activity in mammalian and quail tissue, particularly in the brain. We show that this activity is mainly due to Prune, an exopolyphosphatase overexpressed in metastatic tumors where it promotes cell motility. CONCLUSIONS AND GENERAL SIGNIFICANCE: We show for the first time that PPPase activities are widespread in bacteria and animals. We identified the enzymes responsible for these activities but we were unable to detect significant amounts of PPP(i in E. coli or brain extracts using ion chromatography and capillary electrophoresis. The role of these enzymes may be to hydrolyze PPP(i, which could be cytotoxic because of its high affinity for Ca(2+, thereby interfering with Ca(2+ signaling.

  8. Heterotrophic bacterial production and extracellular enzymatic activity in sinking particulate matter in the western North Pacific Ocean

    Directory of Open Access Journals (Sweden)

    Namiha eYamada

    2012-10-01

    Full Text Available Heterotrophic activities on sinking particulate matter (SPM play an important role in SPM fluxes in the ocean. To demonstrate regional differences in heterotrophic activities on SPM, we measured heterotrophic bacterial production (HBP in seawater and SPM as well as potential extracellular enzyme activity (EEA in SPM on a transect along 155°E in the western North Pacific Ocean in the subarctic (44°N, the Kuroshio Extension area (35°N, and the subtropical gyre (20°N. Depth-integrated HBP in seawater from the surface to 500 m was comparable between the locations, whereas HBP in SPM at 44°N was substantially lower than at the other sites. We found the highest particulate organic carbon (POC export flux and export efficiency to bathypelagic depths, and the lowest water temperatures, at 44°N. We found significant correlations between leucine aminopeptidase (LAPase activity, ß-glucosidase (BGase activity, POC flux and particulate organic nitrogen flux. LAPase activity was two orders of magnitude higher than BGase activity, with a BGase:LAPase activity ratio of 0.027. There were no significant correlations between HBP and EEA in SPM except for lipase, and lipase activity was significantly correlated with temperature. We propose that hydrographic conditions are an important factor controlling heterotrophic bacterial activity and export efficiency of organic carbon to the deep ocean, as are the sources and abundance of SPM produced in the euphotic zone via primary production.

  9. Activities involving aeronautical, space science, and technology support for minority institutions

    Science.gov (United States)

    1993-01-01

    The Final Report addressed the activities with which the Interracial Council for Business Opportunity (ICBO) was involved over the past 12 months. ICBO was involved in the design and development of a CARES Student Tracking System Software (CARES). Cares is intended to provide an effective means of maintaining relevant current and historical information on NASA-funded students through a range of educational program initiatives. ICBP was extensively involved in the formation of a minority university consortium amd implementation of collaborative research activities by the consortium as part of NASA's Mission to Planet Earth/Earth Observing System. ICBO was involved in the formation of an HBCU/MI Consortium to facilitate technology transfer efforts to the small and minority business community in their respective regions.

  10. Distinct summer and winter bacterial communities in the active layer of Svalbard permafrost revealed by DNA- and RNA-based analyses

    DEFF Research Database (Denmark)

    Schostag, Morten; Stibal, Marek; Jacobsen, Carsten S.

    2015-01-01

    N) by co-extracting DNA and RNA from 12 soil cores collected monthly over a year. PCR amplicons of 16S rRNA genes (DNA) and reverse transcribed transcripts (cDNA) were quantified and sequenced to test for the effect of low winter temperature and seasonal variation in concentration of easily degradable...... organic matter on the bacterial communities. The copy number of 16S rRNA genes and transcripts revealed no distinct seasonal changes indicating potential bacterial activity during winter despite soil temperatures well below -10ºC. Multivariate statistical analysis of the bacterial diversity data (DNA......The active layer of soil overlaying permafrost in the Arctic is subjected to dramatic annual changes in temperature and soil chemistry, which likely affect bacterial activity and community structure. We studied seasonal variations in the bacterial community of active layer soil from Svalbard (78º...

  11. Modification of activities of the ruminal ecosystem and its bacterial and protozoan composition during repeated dietary changes in cows.

    Science.gov (United States)

    Monteils, V; Rey, M; Silberberg, M; Cauquil, L; Combes, S

    2012-12-01

    Dietary change alters the ruminal ecosystem and can be regarded as a disturbance. Studying the response to a disturbance can help us understand the behavior of the ecosystem. Our work is concerned with the response of the ruminal ecosystem (composition and activities) during the application of repeated dietary disturbances to 6 dry Holstein cows. For 2 mo, the cows received a hay-based diet [experimental period (EP) 0], followed by 3 EP of successive changes (EP 1, 2, and 3) comprised of 2 parts: the first (10 d) with a corn silage-based diet and the second (25 d) with a hay-based diet. The measurements and samplings were done on the last days of EP 0 and of each part of EP 1 through 3, with the results of EP 0 used as covariables in the statistical models. The physicochemical measurements (pH and redox potential) and the fermentation variables (VFA, ammonia) were determined hourly between the morning and evening meals (n = 8 measurements/d). Samples of ruminal contents were taken 3 h after the morning meal to determine enzymatic activity [amylase, carboxymethyl cellulase (CMCase), and xylanase], to count the main protozoan genera and to quantify the bacteria by quantitative PCR, and to determine its structure by the capillary electrophoresis single-strand conformation polymorphism process. The pH fell for the corn silage-based diet with the EP (P highest value was observed for EP 2 (P bacterial community was not affected by the disturbances for the corn silage-based diet, whereas for the hay-based diet large differences were evident between EP 1 and 3 (P < 0.05) and 2 and 3 (P < 0.01). The number of protozoa increased over the EP, with a more marked effect for the corn silage-based diet (diet × EP interaction, P < 0.05). The specific amylase, CMCase, and xylanase activities decreased over the EP for both diets (P < 0.05). The dietary changes applied in our experiment involved strong modifications of the ruminal ecosystem and alterations of ruminal fermentation

  12. Isolation and Identification of Active Compound Cause Light Emmitting of Bacterial Photobacterium phosphoreum Isolated from the Indonesia Jepara Marine Squid

    Directory of Open Access Journals (Sweden)

    Idam Arif

    2005-04-01

    Full Text Available This research carried out to study the bioluminescence process of bacterial Photobacterium phosphoreum isolated from Indonesia marine squid. The method used in the present study involved isolation, purification, electrophoresis, and the absorbance and light intensity measurement. This result show that the luciferace enzyme of bacterial Photobacterium phosphoreum or called LBPP catalyzes the emission of visible light from the reaction of reduced flavin mononucleotide (FMNH2, molecular oxygen (O2, and an aldehyde (RCOH. The electrophoresis data show that LBPP comprised of two different subunits α and βwith 41kD and 38 kD molecular weights. The absorb pattern showed that the bioluminescence process centered around 516 nm and are consistent with the fluorescence data. This result concluded that the excitation state formed after LBPP bind subtracts and the ground state formed after LBPP releases product and visible light.

  13. Bacterial diversity and distribution in the southeast edge of the Tengger Desert and their correlation with soil enzyme activities

    Institute of Scientific and Technical Information of China (English)

    Wei Zhang; Gaosen Zhang; Guangxiu Liu; Zhibao Dong; Tuo Chen; Manxiao Zhang; Paul J.Dyson; Lizhe An

    2012-01-01

    The nature of microbial communities and their relation to enzyme activities in desert soils is a neglected area of investigation.To address this,the bacterial diversity and distribution and soil physico-chemical factors were investigated in the soil crust,the soil beneath the crust and rhizosphere soil at the southeast edge of the Tengger Desert,using the denaturing gradient gel electrophoresis of 16S rRNA genes amplified by the polymerase chain reaction.Phylogenetic analysis of the sequenced DGGE bands revealed a great diversity of bacteria.The Proteobacteria,consisting of the α,β,and γ subdivisions,were clearly the dominant group at all depths and in rhizosphere soil.Analysis of the enzyme activities indicated that the rhizosphere soil of Caragana korshinskii exhibited the highest protease and polyphenol oxidase activities,and in the soil crust there were increased activities of catalase,urease,dehydrogenase and sucrase.The bacterial community abundance closely correlated with soil enzyme activities in different soils.The presence of Cyanobacteria correlated with significant increases in protease,catalase and sucrase in the soil crust,and increased urease in the rhizosphere soil of Artemisia ordosica.The occurrence of Acidobacteria was associated with significant increases in urease,dehydrogenase,and sucrase in the rhizosphere soil of C.korshinski.The presence of γ-Proteobacteria correlated with a significant increase in polyphenol oxidase in the rhizosphere soil of A.ordosica.The study indicated a close relationship between the soil bacterial community and soil enzymes,suggesting the necessity of further investigations into bacterial function in this desert ecosystem.

  14. Bacterial biomass and activity in the deep waters of the eastern Atlantic—evidence of a barophilic community

    Science.gov (United States)

    Patching, J. W.; Eardly, D.

    1997-09-01

    Bacterial biomass and activity were investigated in deep waters at two sites in the eastern Atlantic, of similar depth (4560-4800 m), but varying in their nutritional status. The Northern (N) site was eutrophic and subject to a strong seasonal input of surface derived organic matter (phytodetritus) to the sediment. The Southern (S) site was oligotrophic. Deep water at this site does not appear to receive any strong seasonal input. Bacterial numbers in the deep water column at the N site showed no significant seasonal variation but were greater than those at the S site. Deep water bacteria were typically small and free-living. From biovolume determinations, it was estimated that mean concentrations of bacterial organic carbon at depths greater than 500 m were 0.12 (0.03-0.29) μg C 1 -1 and 0.02 (0.01-0.04) μg C 1 -1 at the N and S sites, respectively. Rates of thymidine and leucine incorporation were used as indicators of bacterial activity. Bacterial communities in water in contact with the sediment (SCW; sediment contact water) at both sites (but especially at the S site) were strongly barophilic at in situ temperatures (2.5-4.1°C). The barophilic response of thymidine incorporation was enhanced when SCW samples from the N site were incubated at 11.5°C. It is proposed that this result indicated an elevating effect of pressure on cardinal temperatures and that the SCW community was obligately psychrophilic when unpressurised. Comparison of cell-specific incorporation rates determined under in situ conditions showed bacteria in the SCW to have levels of activity comparable with bacteria from a depth of 150 m. Thymidine incorporation rates were highest in SCW samples taken at the N site in May 1988 and September 1989. Thymidine incorporation by SCW samples taken immediately before (10 April 1994) the main spring-bloom-associated deposition of phytodetritus was significantly lower and comparable with that determined for the oligotrophic S site. The attributes

  15. In vitro antibacterial activity of venom protein isolated from sea snake Enhydrina schistosa against drugresistant human pathogenic bacterial strains

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    Palani Damotharan

    2015-06-01

    Full Text Available Objective: To evaluate the antibacterial activity of sea snake (Enhydrina schistosa venom protein against drug-resistant human pathogenic bacterial strains. Methods: The venom was collected by milking process from the live specimens of sea snake are using capillary tubes or glass plates. Venom was purified by ion exchange chromatography and it was tested for in-vitro antibacterial activity against 10 drug-resistant human pathogenic bacterial strains using the standard disc diffusion method. Results: The notable antibacterial activity was observed at 150 µg/mL concentration of purified venom and gave its minimum inhibitory concentrations values exhibited between 200-100 µg/mL against all the tested bacterial strains. The maximum zone of inhibition was observed at 16.4 mm against Salmonella boydii and the minimum activity was observed at 7.5 mm against Pseudomonas aeruginosa. After the sodium-dodecyl-sulfate-polyacrylamide gel electrophoresis there were a clear single band was detected in the gel that corresponding to purified venom protein molecular weight of 44 kDa. Conclusions: These results suggested that the sea snake venom might be a feasible source for searching potential antibiotics agents against human pathogenic diseases.

  16. Design, synthesis and antibacterial activity of cinnamaldehyde derivatives as inhibitors of the bacterial cell division protein FtsZ.

    Science.gov (United States)

    Li, Xin; Sheng, Juzheng; Huang, Guihua; Ma, Ruixin; Yin, Fengxin; Song, Di; Zhao, Can; Ma, Shutao

    2015-06-05

    In an attempt to discover potential antibacterial agents against the increasing bacterial resistance, novel cinnamaldehyde derivatives as FtsZ inhibitors were designed, synthesized and evaluated for their antibacterial activity against nine significant pathogens using broth microdilution method, and their cell division inhibitory activity against four representative strains. In the in vitro antibacterial activity, the newly synthesized compounds generally displayed better efficacy against Staphylococcus aureus ATCC25923 than the others. In particular, compounds 3, 8 and 10 exerted superior or comparable activity to all the reference drugs. In the cell division inhibitory activity, all the compounds showed the same trend as their in vitro antibacterial activity, exhibiting better activity against S. aureus ATCC25923 than the other strains. Additionally, compounds 3, 6, 7 and 8 displayed potent cell division inhibitory activity with an MIC value of below 1 μg/mL, over 256-fold better than all the reference drugs.

  17. Involvement of Ca2+ Activated Cl- Channel Ano6 in Platelet Activation and Apoptosis

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    Guoxing Liu

    2015-11-01

    Full Text Available Background/Aims: The ubiquitously expressed Ca2+ Activated Cl- Channel Ano6 participates in the stimulation of cell membrane scrambling. Defective Ano6 underlies the Scott syndrome, an inherited bleeding disorder with impaired scrambling of plasma membrane phospholipids. At least in theory, the bleeding disorder of Scott syndrome may result from impaired platelet function. Activators of platelets include thrombin and collagen related peptide (CRP, which trigger increase of cytosolic Ca2+-activity ([Ca2+]i, production of reactive oxygen species (ROS, degranulation, integrin activation, as well as cell shrinkage and phospholipid scrambling of the cell membrane. The present study thus explored whether Ano6 modifies activation-induced alterations of cytosolic Ca2+-activity ([Ca2+]i, degranulation (P-selectin exposure, integrin activation, phosphatidylserine exposure on the platelet surface and platelet volume. Methods: Platelets from mice lacking Ano6 (ano6-/- were compared to platelets from corresponding wild-type mice (ano6+/+. [Ca2+]i was estimated from Fluo-3 fluorescence, ROS from DCFDA fluorescence, degranulation from P-selectin abundance, integrin activation from αIIbβ3-integrin abundance, phosphatidylserine abundance from annexin-V-binding, and cell volume from forward scatter. Results: Platelet number in blood was slightly higher in ano6-/- mice than in ano6+/+ mice. Without activation [Ca2+]i and volume were similar in ano6-/- and ano6+/+ platelets as well as ROS abundance, P-selectin abundance, αIIbβ3 integrin activation, and phosphatidylserine exposure were negligible in both genotypes. Thrombin (0.01 U/ml and CRP (2 or 5 µg/ml increased [Ca2+]i, ROS abundance, platelet degranulation, αIIbβ3 integrin activation, and triggered annexin-V-binding as well as cell shrinkage, all effects less pronounced in ano6-/- than in ano6+/+ platelets. Conclusions: Genetic knockout of Ano6 blunts thrombin- and CRP-induced activation and apoptosis

  18. An aromatic residue switch in enhancer-dependent bacterial RNA polymerase controls transcription intermediate complex activity

    Science.gov (United States)

    Wiesler, Simone C.; Weinzierl, Robert O. J.; Buck, Martin

    2013-01-01

    The formation of the open promoter complex (RPo) in which the melted DNA containing the transcription start site is located at the RNA polymerase (RNAP) catalytic centre is an obligatory step in the transcription of DNA into RNA catalyzed by RNAP. In the RPo, an extensive network of interactions is established between DNA, RNAP and the σ-factor and the formation of functional RPo occurs via a series of transcriptional intermediates (collectively ‘RPi’). A single tryptophan is ideally positioned to directly engage with the flipped out base of the non-template strand at the +1 site. Evidence suggests that this tryptophan (i) is involved in either forward translocation or DNA scrunching and (ii) in σ54-regulated promoters limits the transcription activity of at least one intermediate complex (RPi) before the formation of a fully functional RPo. Limiting RPi activity may be important in preventing the premature synthesis of abortive transcripts, suggesting its involvement in a general mechanism driving the RPi to RPo transition for transcription initiation. PMID:23609536

  19. Activating the expression of bacterial cryptic genes by rpoB mutations in RNA polymerase or by rare earth elements.

    Science.gov (United States)

    Ochi, Kozo; Tanaka, Yukinori; Tojo, Shigeo

    2014-02-01

    Since bacteria were found to contain genes encoding enzymes that synthesize a plethora of potential secondary metabolites, interest has grown in the activation of these cryptic pathways. Homologous and heterologous expression of these cryptic secondary metabolite-biosynthetic genes, often "silent" under ordinary laboratory fermentation conditions, may lead to the discovery of novel secondary metabolites. We review current progress on this topic, describing concepts for activating silent genes. We especially focus on genetic manipulation of transcription and translation, as well as the utilization of rare earth elements as a novel method to activate the silent genes. The possible roles of silent genes in bacterial physiology are also discussed.

  20. Factors Involved in Iranian Women Heads of Household's Health Promotion Activities: A Grounded Theory Study.

    Science.gov (United States)

    Rafii, Forough; Seyedfatemi, Naima; Rezaei, Mahboubeh

    2013-01-01

    We aimed to explore and describe the factors involved in Iranian women heads of household's health promotion activities. Grounded theory was used as the method. Sixteen women heads of household were recruited. Data were generated by semi structured interviews. Our findings indicated that remainder of resources (money, time and energy) alongside perceived severity of health risk were two main factors whereas women's personal and socio-economic characteristics were two contextual factors involved in these women's health promotion activities. To help these women improve their health status, we recommended that the government, non-governmental organizations and health care professionals provide them with required resources and increase their knowledge by holding training sessions.

  1. Active serine involved in the stabilization of the active site loop in the Humicola lanuginosa lipase

    DEFF Research Database (Denmark)

    Peters, Günther H.j.; Svendsen, A.; Langberg, H.;

    1998-01-01

    reveal that the hinges of the active site lid are more flexible in the wild-type Hll than in S146A. In contrast, larger fluctuations are observed in the middle region of the active site loop in S 146A than in Hll. These findings reveal that the single mutation (S146A) of the active site serine leads......We have investigated the binding properties of and dynamics in Humicola lanuginosa lipase (HII) and the inactive mutant S146A (active Ser146 substituted with Ala) using fluorescence spectroscopy and molecular dynamics simulations, respectively. Hll and S146A show significantly different binding......, whereas only small changes are observed for I-Ill suggesting that the active site Lid in the latter opens more easily and hence more lipase molecules are bound to the liposomes. These observations are in agreement with molecular dynamics simulations and subsequent essential dynamics analyses. The results...

  2. Impacts of multiwalled carbon nanotubes on nutrient removal from wastewater and bacterial community structure in activated sludge.

    Directory of Open Access Journals (Sweden)

    Reti Hai

    Full Text Available BACKGROUND: The increasing use of multiwalled carbon nanotubes (MWCNTs will inevitably lead to the exposure of wastewater treatment facilities. However, knowledge of the impacts of MWCNTs on wastewater nutrient removal and bacterial community structure in the activated sludge process is sparse. AIMS: To investigate the effects of MWCNTs on wastewater nutrient removal, and bacterial community structure in activated sludge. METHODS: Three triplicate sequencing batch reactors (SBR were exposed to wastewater which contained 0, 1, and 20 mg/L MWCNTs. MiSeq sequencing was used to investigate the bacterial community structures in activated sludge samples which were exposed to different concentrations of MWCNTs. RESULTS: Exposure to 1 and 20 mg/L MWCNTs had no acute (1 day impact on nutrient removal from wastewater. After long-term (180 days exposure to 1 mg/L MWCNTs, the average total nitrogen (TN removal efficiency was not significantly affected. TN removal efficiency decreased from 84.0% to 71.9% after long-term effects of 20 mg/L MWCNTs. After long-term exposure to 1 and 20 mg/L MWCNTs, the total phosphorus removal efficiencies decreased from 96.8% to 52.3% and from 98.2% to 34.0% respectively. Further study revealed that long-term exposure to 20 mg/L MWCNTs inhibited activities of ammonia monooxygenase and nitrite oxidoreductase. Long-term exposure to 1 and 20 mg/L MWCNTs both inhibited activities of exopolyphosphatase and polyphosphate kinase. MiSeq sequencing data indicated that 20 mg/L MWCNTs significantly decreased the diversity of bacterial community in activated sludge. Long-term exposure to 1 and 20 mg/L MWCNTs differentially decreased the abundance of nitrifying bacteria, especially ammonia-oxidizing bacteria. The abundance of PAOs was decreased after long-term exposure to 20 mg/L MWCNTs. The abundance of glycogen accumulating organisms (GAOs was increased after long-term exposure to 1 mg/L MWCNTs. CONCLUSION: MWCNTs have adverse effects on

  3. Association of markers of bacterial translocation with immune activation in decompensated cirrhosis

    DEFF Research Database (Denmark)

    Mortensen, Christian; Jensen, Jørgen Skov; Hobolth, Lise;

    2014-01-01

    BACKGROUND: Bacterial translocation (BT) may cause infections, in particular, spontaneous bacterial peritonitis (SBP). In the absence of overt infection, BT may further stimulate the immune system and contribute to haemodynamic alterations and complications. Bacterial DNA (bDNA) is claimed...... or positive cultures, we found a high frequency of bDNA but low concordance of bDNA between blood and ascites. Markers of inflammation were not significantly different between blood bDNA-positive (22%), ascites bDNA-positive (52%), and bDNA-negative patients. The 16S rDNA PCR failed to show bDNA in two out...... of six samples with SBP. Sequencing of positive samples did not determine the source of bDNA. CONCLUSION: bDNA as assessed by this PCR method was largely unrelated to markers of inflammation and does not seem to be of clinical value in the diagnosis of SBP. According to our results, b...

  4. Antibiotic activity and concentrations in clinical samples from patients with chronic bacterial prostatitis.

    Science.gov (United States)

    Heras-Cañas, V; Gutiérrez-Soto, B; Almonte-Fernández, H; Lara-Oya, A; Navarro-Marí, J M; Garrido-Frenich, A; Vázquez-Alonso, F; Gutiérrez-Fernández, J

    2017-06-19

    Chronic bacterial prostatitis (CBP) is the most common urological disease in patients younger than 50 years, whose long-standing symptoms could be related to an inappropriate therapeutic regimen. The objective was to analyse the sensitivity of microorganisms isolated from patients with CBP and measure the weekly antibiotic concentrations in serum, semen and urine. For the antibiotic sensitivity study, 60 clinical isolates were included between January 2013 and December 2014 from semen samples from patients with microbiologically confirmed CBP. Broth microdilution was performed on the samples. For the antibiotic concentration study from January to May 2014, urine, blood and semen samples were collected weekly, over 4 weeks of treatment from 8 patients with positive cultures for CBP. The concentrations were measured using ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). The antibiotics fosfomycin and nitrofurantoin had the highest activity (95.2% in both cases). The mean antibiotic concentrations in semen during the 4 weeks studied were as follows: 1.68mg/L, 8.30mg/L, 2.61mg/L, 0.33mg/L and 2.90mg/L, respectively, for patients 1 to 5, who were treated with levofloxacin; 1.625mg/L for patient 6, who was treated with ciprofloxacin; 2.67mg/L for patient 7, who was treated with ampicillin; and 1.05mg/L for patient 8, who was treated with doxycycline. Higher concentrations were obtained in the urine samples than in serum and semen, the latter 2 of which were comparable. Fosfomycin is proposed as the primary alternative to the empiric treatment of CBP due to its high in vitro activity. The antibiotic concentration in semen was higher than the minimal inhibitory concentration against the aetiological agent, although microbiological negativisation was not always correlated with a favourable clinical outcome. Copyright © 2017 AEU. Publicado por Elsevier España, S.L.U. All rights reserved.

  5. Pyrosequencing reveals soil enzyme activities and bacterial communities impacted by graphene and its oxides.

    Science.gov (United States)

    Rong, Yan; Wang, Yi; Guan, Yina; Ma, Jiangtao; Cai, Zhiqiang; Yang, Guanghua; Zhao, Xiyue

    2017-09-26

    Graphene (GN) and graphene oxides (GOs) are novel carbon nanomaterial, they have been attracted much attention because of their excellent properties and are widely applied in many areas including energy, electronics, biomedicine and environmental science etc. With industrial production and consumption of GN/GO, they will inevitably enter the soil and water environment. GN/GO may directly cause certain harm to microorganisms and lead to ecological and environmental risks. Graphene oxides are graphene derivative with abundant oxygen-containing functional groups in its graphitic backbone. The structure and chemistry of graphene show obvious differences compared with graphene oxide, which lead to the different environmental behaviors. In this study, four different types of soil (S1, S2, S3 and S4) were employed to investigate the effect of GN and GO on soil enzymatic activity, microbial population and bacterial community through pyrosequencing of 16S rRNA gene amplicons. The results showed that soil enzyme activity (invertase, protease, catalase and urease) and microbial population (bacteria, actinomycete and fungi) changed after GN/GO release into soils. Soil microbial community species are more richness and the diversity also increase after GO/GN application. The phylum of Proteobacteria increased at 90 days after treatment (DAT) after GN/GO application. The phylum of Chloroflexi occurred after GN applying at 90 DAT in S1 and reached 4.6%. Proteobacteria were the most phylum in S2, S3 and S4 soils, it ranged from 43.6% to 71.4% in S2, 45.6% to 73.7% in S3, 38.1% to 56.7% in S4, respectively. The most abundant genus were Bacillus (37.5% - 47.0%), Lactococcus (28.0% - 39.0%) in S1, Lysobacter and Flavobacterium in S2, Pedobacter in S3 and Massilia in S4 soil. The effect of GN and GO on soil microbial community is time dependent, and there are no significant differences between the samples at 10 and 90 DAT.

  6. Simultaneous spatiotemporal mapping of in situ pH and bacterial activity within an intact 3D microcolony structure

    Science.gov (United States)

    Hwang, Geelsu; Liu, Yuan; Kim, Dongyeop; Sun, Victor; Aviles-Reyes, Alejandro; Kajfasz, Jessica K.; Lemos, Jose A.; Koo, Hyun

    2016-01-01

    Biofilms are comprised of bacterial-clusters (microcolonies) enmeshed in an extracellular matrix. Streptococcus mutans can produce exopolysaccharides (EPS)-matrix and assemble microcolonies with acidic microenvironments that can cause tooth-decay despite the surrounding neutral-pH found in oral cavity. How the matrix influences the pH and bacterial activity locally remains unclear. Here, we simultaneously analyzed in situ pH and gene expression within intact biofilms and measured the impact of damage to the surrounding EPS-matrix. The spatiotemporal changes of these properties were characterized at a single-microcolony level following incubation in neutral-pH buffer. The middle and bottom-regions as well as inner-section within the microcolony 3D structure were resistant to neutralization (vs. upper and peripheral-region), forming an acidic core. Concomitantly, we used a green fluorescent protein (GFP) reporter to monitor expression of the pH-responsive atpB (PatpB::gfp) by S. mutans within microcolonies. The atpB expression was induced in the acidic core, but sharply decreased at peripheral/upper microcolony regions, congruent with local pH microenvironment. Enzymatic digestion of the surrounding matrix resulted in nearly complete neutralization of microcolony interior and down-regulation of atpB. Altogether, our data reveal that biofilm matrix facilitates formation of an acidic core within microcolonies which in turn activates S. mutans acid-stress response, mediating both the local environment and bacterial activity in situ. PMID:27604325

  7. Simultaneous spatiotemporal mapping of in situ pH and bacterial activity within an intact 3D microcolony structure

    Science.gov (United States)

    Hwang, Geelsu; Liu, Yuan; Kim, Dongyeop; Sun, Victor; Aviles-Reyes, Alejandro; Kajfasz, Jessica K.; Lemos, Jose A.; Koo, Hyun

    2016-09-01

    Biofilms are comprised of bacterial-clusters (microcolonies) enmeshed in an extracellular matrix. Streptococcus mutans can produce exopolysaccharides (EPS)-matrix and assemble microcolonies with acidic microenvironments that can cause tooth-decay despite the surrounding neutral-pH found in oral cavity. How the matrix influences the pH and bacterial activity locally remains unclear. Here, we simultaneously analyzed in situ pH and gene expression within intact biofilms and measured the impact of damage to the surrounding EPS-matrix. The spatiotemporal changes of these properties were characterized at a single-microcolony level following incubation in neutral-pH buffer. The middle and bottom-regions as well as inner-section within the microcolony 3D structure were resistant to neutralization (vs. upper and peripheral-region), forming an acidic core. Concomitantly, we used a green fluorescent protein (GFP) reporter to monitor expression of the pH-responsive atpB (PatpB::gfp) by S. mutans within microcolonies. The atpB expression was induced in the acidic core, but sharply decreased at peripheral/upper microcolony regions, congruent with local pH microenvironment. Enzymatic digestion of the surrounding matrix resulted in nearly complete neutralization of microcolony interior and down-regulation of atpB. Altogether, our data reveal that biofilm matrix facilitates formation of an acidic core within microcolonies which in turn activates S. mutans acid-stress response, mediating both the local environment and bacterial activity in situ.

  8. On-Demand Removal of Bacterial Biofilms via Shape Memory Activation.

    Science.gov (United States)

    Gu, Huan; Lee, Sang Won; Buffington, Shelby Lois; Henderson, James H; Ren, Dacheng

    2016-08-24

    Bacterial biofilms are a major cause of chronic infections and biofouling; however, effective removal of established biofilms remains challenging. Here we report a new strategy for biofilm control using biocompatible shape memory polymers with defined surface topography. These surfaces can both prevent bacterial adhesion and remove established biofilms upon rapid shape change with moderate increase of temperature, thereby offering more prolonged antifouling properties. We demonstrate that this strategy can achieve a total reduction of Pseudomonas aeruginosa biofilms by 99.9% compared to the static flat control. It was also found effective against biofilms of Staphylococcus aureus and an uropathogenic strain of Escherichia coli.

  9. In vitro activity of aminosterols against yeasts involved in blood stream infections.

    Science.gov (United States)

    Alhanout, Kamel; Djouhri, Lamia; Vidal, Nicolas; Brunel, Jean Michel; Piarroux, Renaud; Ranque, Stéphane

    2011-02-01

    Squalamine and other aminosterols have demonstrated interesting antimicrobial activities against clinical bacterial isolates and a limited number of reference yeast strains. We aimed to test whether squalamine and a synthetic aminosterol derivative (ASD) display any in vitro activity comparable to currently available systemic antifungals, an acceptable safety index, as well as to provide insights into their mechanism of action. The minimum inhibitory concentrations (MICs) of squalamine, ASD and available antifungals were determined against 21 yeast isolates that were recovered from cases of fungemia. Remarkably, homogeneous MICs ranging from 8-16 mg/L and from 1-2 mg/L were noted for squalamine and ASD, respectively, as opposes the heterogeneous in vitro activity of available systemic antifungals. Aminosterols induced haemolysis, a surrogate for toxic effects to mammalian cells, at concentrations high above their MICs. In time-kill studies, killing was as fast with ASD as with amphotericin B. Both aminosterols induced a time-dependent disruption of yeast membrane, as evidenced by gradual increase of ATP efflux. In conclusion, our preliminary data indicate that aminosterols have the potential to be further developed as antifungals. Additional work is warranted to assess their toxicity and activity in experimental models.

  10. Active Involvement of End Users When Developing Web-Based Mental Health Interventions.

    Science.gov (United States)

    de Beurs, Derek; van Bruinessen, Inge; Noordman, Janneke; Friele, Roland; van Dulmen, Sandra

    2017-01-01

    Although many web-based mental health interventions are being released, the actual uptake by end users is limited. The marginal level of engagement of end users when developing these interventions is recognized as an important cause for uptake problems. In this paper, we offer our perceptive on how to improve user engagement. By doing so, we aim to stimulate a discourse on user involvement within the field of online mental health interventions. We shortly describe three different methods (the expert-driven method, intervention mapping, and scrum) that were currently used to develop web-based health interventions. We will focus to what extent the end user was involved in the developmental phase, and what the additional challenges were. In the final paragraph, lessons learned are summarized, and recommendations provided. Every method seems to have its trade-off: if end users are highly involved, availability of end users and means become problematic. If end users are less actively involved, the product may be less appropriate for the end user. Other challenges to consider are the funding of the more active role of technological companies, and the time it takes to process the results of shorter development cycles. Thinking about user-centered design and carefully planning, the involvement of end users should become standard in the field of web-based (mental) health. When deciding on the level of user involvement, one should balance the need for input from users with the availability of resources such as time and funding.

  11. THE INFLUENCE OF STUDENTS’ INVOLVEMENT IN EXTRACURRICULAR ACTIVITIES ON THE DEVELOPMENT OF SKILLS AND COMPETENCIES

    Directory of Open Access Journals (Sweden)

    Oana DUMITRASCU

    2015-11-01

    Full Text Available The paper aims to demonstrate the influence of students’ involvement in extracurricular activities on the development of skills and competencies by means of the factorial analysis. This research is untertaken by means of the questionnaire method, where 728 respondents from five Romanian universities where questionned. The data is analysed through the statistical programme SPSS. Due to the factorial analysis certain influences of the extracurricular activities on the organisational skills, social competencies, communication skills and integration ability are highlighted.

  12. Antibacterial Activity of Ethyl Acetate the Extract of Noni Fruit (Morinda citrifolia L.) Against Bacterial Spoilage in Fish

    Science.gov (United States)

    Nugraheni, E. R.; Adriani, G. R.; Munawaroh, H.

    2017-04-01

    Noni fruit (Morinda citrifolia L.) contains compounds that have potential as antibacterial agent. Antibacterial compounds produced noni fruit (M. citrifolia L.) can inhibit bacterial growth. This study was conducted to test the antibacterial activity of ethyl acetate extract of noni fruit (M. citrifolia L.) against spoilage bacterial in fish. Pseudomonas aeruginosa, Bacillus cereus, Escherichia coli, Klebsiella oxytoca, and Enterobacter aerogenes isolates and examine antibacterial phytochemical profile. Extraction of noni compounds was done by maceration, followed by partition with ethyl acetate to obtain the soluble and insoluble ethyl acetate fraction. Previews result show that the ethyl acetate extract had very strong activity. Extraction process continued by separation and isolation used preparative thin layer chromatography method, so that obtained five isolates and mark them as A, B, C, D and E. Antibacterial activity assay performed on isolates A, B, C, D, and E with 20 and 30% concentration. The test results showed that isolates A could not be inhibit the growth of bacteria, isolates B, C, D, and E has antibacterial activity with weak to strong inhibition. Isolate B had the greatest inhibition activity against the B. cereus, whereas isolates E had the greatest inhibition activity against P. aeroginosa. MIC (Minimum Inhibitor Concentration) and MBC (Minimum Bactericidal Concentration) test result showed that MIC and MBC values could not be determined. Analysis of compounds by TLC showed that isolate B suspected contains coumarin or flavonoids compounds that have antibacterial activity.

  13. Bacterial ghosts as novel advanced drug delivery systems: antiproliferative activity of loaded doxorubicin in human Caco-2 cells.

    Science.gov (United States)

    Paukner, Susanne; Kohl, Gudrun; Lubitz, Werner

    2004-01-08

    Systemic application of anticancer drugs often causes severe toxic side effects. To reduce the undesired effects, advanced drug delivery systems are needed which are based on specific cell targeting vehicles. In this study, bacterial ghosts from Mannheimia haemolytica were used for site-specific delivery of doxorubicin (DOX) to human colorectal adenocarcinoma cells (Caco-2). Bacterial ghosts are non-denatured envelopes of Gram-negative bacteria with fully intact surface structures for specific attachment to mammalian cells. The in vitro release profile of DOX-ghosts demonstrated that the loaded drug was non-covalently associated with the bacterial ghosts and that the drug delivery vehicles themselves represent a slow release system. Adherence studies showed that the M. haemolytica ghosts more efficiently than E. coli ghosts targeted the Caco-2 cells and released the loaded DOX within the cells. Cytotoxicity assays revealed that the DOX-ghosts exhibited potent antiproliferative activities on Caco-2 cells as the DOX associated with ghosts was two magnitude of orders more cytotoxic than free DOX provided in the medium at the same concentrations. Notably, a significant reduction in the cell viability was measured with DOX-ghosts at low DOX concentrations, which had no inhibitory effect when applied as free DOX after incubation for 16 h or when applied at higher concentrations for only 10 min to the cells. As the higher antiproliferative effects of DOX on Caco-2 cells were mediated by the specific drug targeting properties of the bacterial ghosts, the bacterial ghost system represents a novel platform for advanced drug delivery.

  14. Evaluation of Analgesic Activity of Papaver libanoticum Extract in Mice: Involvement of Opioids Receptors

    Directory of Open Access Journals (Sweden)

    Mohamad Ali Hijazi

    2017-01-01

    Full Text Available Papaver libanoticum is an endemic plant to Lebanese region (family Papaveraceae that has not been investigated before. The present study aimed to explore the analgesic activity of dried ethanolic extract of Papaver libanoticum (PLE using tail flick, hot plate, and acetic acid induced writhing models in mice. The involvement of opioid receptors in the analgesic mechanism was investigated using naloxone antagonism. Results demonstrated that PLE exhibited a potent dose dependent analgesic activity in all tested models for analgesia. The analgesic effect involved activation of opioid receptors in the central nervous system, where both spinal and supraspinal components might be involved. The time course for analgesia revealed maximum activity after three hours in both tail flick and hot plate methods, which was prolonged to 24 hours. Metabolites of PLE could be responsible for activation of opioid receptors. The EC50 of PLE was 79 and 50 mg/kg in tail flick and hot plate tests, respectively. The total coverage of analgesia by PLE was double that of morphine in both tests. In conclusion, PLE proved to have opioid agonistic activity with a novel feature of slow and prolonged effect. The present study could add a potential tool in the armaments of opioid drugs as a natural potent analgesic and for treatment of opioid withdrawal syndrome.

  15. Evaluation of Analgesic Activity of Papaver libanoticum Extract in Mice: Involvement of Opioids Receptors

    Science.gov (United States)

    El-Mallah, Ahmed; Aboul-Ela, Maha; Ellakany, Abdalla

    2017-01-01

    Papaver libanoticum is an endemic plant to Lebanese region (family Papaveraceae) that has not been investigated before. The present study aimed to explore the analgesic activity of dried ethanolic extract of Papaver libanoticum (PLE) using tail flick, hot plate, and acetic acid induced writhing models in mice. The involvement of opioid receptors in the analgesic mechanism was investigated using naloxone antagonism. Results demonstrated that PLE exhibited a potent dose dependent analgesic activity in all tested models for analgesia. The analgesic effect involved activation of opioid receptors in the central nervous system, where both spinal and supraspinal components might be involved. The time course for analgesia revealed maximum activity after three hours in both tail flick and hot plate methods, which was prolonged to 24 hours. Metabolites of PLE could be responsible for activation of opioid receptors. The EC50 of PLE was 79 and 50 mg/kg in tail flick and hot plate tests, respectively. The total coverage of analgesia by PLE was double that of morphine in both tests. In conclusion, PLE proved to have opioid agonistic activity with a novel feature of slow and prolonged effect. The present study could add a potential tool in the armaments of opioid drugs as a natural potent analgesic and for treatment of opioid withdrawal syndrome. PMID:28280516

  16. Evaluation of Analgesic Activity of Papaver libanoticum Extract in Mice: Involvement of Opioids Receptors.

    Science.gov (United States)

    Hijazi, Mohamad Ali; El-Mallah, Ahmed; Aboul-Ela, Maha; Ellakany, Abdalla

    2017-01-01

    Papaver libanoticum is an endemic plant to Lebanese region (family Papaveraceae) that has not been investigated before. The present study aimed to explore the analgesic activity of dried ethanolic extract of Papaver libanoticum (PLE) using tail flick, hot plate, and acetic acid induced writhing models in mice. The involvement of opioid receptors in the analgesic mechanism was investigated using naloxone antagonism. Results demonstrated that PLE exhibited a potent dose dependent analgesic activity in all tested models for analgesia. The analgesic effect involved activation of opioid receptors in the central nervous system, where both spinal and supraspinal components might be involved. The time course for analgesia revealed maximum activity after three hours in both tail flick and hot plate methods, which was prolonged to 24 hours. Metabolites of PLE could be responsible for activation of opioid receptors. The EC50 of PLE was 79 and 50 mg/kg in tail flick and hot plate tests, respectively. The total coverage of analgesia by PLE was double that of morphine in both tests. In conclusion, PLE proved to have opioid agonistic activity with a novel feature of slow and prolonged effect. The present study could add a potential tool in the armaments of opioid drugs as a natural potent analgesic and for treatment of opioid withdrawal syndrome.

  17. Molecular genetic analysis of activation-tagged transcription factors thought to be involved in photomorphogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Neff, Michael M.

    2011-06-23

    This is a final report for Department of Energy Grant No. DE-FG02-08ER15927 entitled “Molecular Genetic Analysis of Activation-Tagged Transcription Factors Thought to be Involved in Photomorphogenesis”. Based on our preliminary photobiological and genetic analysis of the sob1-D mutant, we hypothesized that OBP3 is a transcription factor involved in both phytochrome and cryptochrome-mediated signal transduction. In addition, we hypothesized that OBP3 is involved in auxin signaling and root development. Based on our preliminary photobiological and genetic analysis of the sob2-D mutant, we also hypothesized that a related gene, LEP, is involved in hormone signaling and seedling development.

  18. Activation of Akt by the bacterial inositol phosphatase, SopB, is wortmannin insensitive.

    Directory of Open Access Journals (Sweden)

    Kendal G Cooper

    Full Text Available Salmonella enterica uses effector proteins translocated by a Type III Secretion System to invade epithelial cells. One of the invasion-associated effectors, SopB, is an inositol phosphatase that mediates sustained activation of the pro-survival kinase Akt in infected cells. Canonical activation of Akt involves membrane translocation and phosphorylation and is dependent on phosphatidyl inositide 3 kinase (PI3K. Here we have investigated these two distinct processes in Salmonella infected HeLa cells. Firstly, we found that SopB-dependent membrane translocation and phosphorylation of Akt are insensitive to the PI3K inhibitor wortmannin. Similarly, depletion of the PI3K regulatory subunits p85α and p85ß by RNAi had no inhibitory effect on SopB-dependent Akt phosphorylation. Nevertheless, SopB-dependent phosphorylation does depend on the Akt kinases, PDK1 and rictor-mTOR. Membrane translocation assays revealed a dependence on SopB for Akt recruitment to Salmonella ruffles and suggest that this is mediated by phosphoinositide (3,4 P(2 rather than phosphoinositide (3,4,5 P(3. Altogether these data demonstrate that Salmonella activates Akt via a wortmannin insensitive mechanism that is likely a class I PI3K-independent process that incorporates some essential elements of the canonical pathway.

  19. Regrouping: organized activity involvement and social adjustment across the transition to high school.

    Science.gov (United States)

    Bohnert, Amy M; Aikins, Julie Wargo; Arola, Nicole T

    2013-01-01

    Although organized activities (OAs) have been established as important contexts of development, limited work has examined the role of OAs across the high school transition in buffering adolescents' social adjustment by providing opportunities for visibility and peer affiliation. The transition to high school is characterized by numerous changes and OAs may provide an important setting for establishing and maintaining peer relationships during this tumultuous time. This study included 151 8th grade U.S. students (58% male) who were assessed across the transition to high school (spring of 8th and 9th grade). Continuous involvement in academic activities across the transition and becoming involved (i.e., initiation) in community/service activities following the transition was associated with fewer depressive symptoms in the spring of 9th grade. Continuous involvement in sports and initiation of academic activities was associated with having more friendships. In addition, links between OAs and loneliness were only evident among females. There appear to be significant social benefits for OA involvement.

  20. Leisure Activity and Caregiver Involvement in Middle-Aged and Older Adults with Down Syndrome

    Science.gov (United States)

    Mihaila, Iulia; Hartley, Sigan L.; Handen, Benjamin L.; Bulova, Peter D.; Tumuluru, Rameshwari V.; Devenny, Darlynne A.; Johnson, Sterling C.; Lao, Patrick J.; Christian, Bradley, T.

    2017-01-01

    The present study examined leisure activity and its association with caregiver involvement (i.e., residence and time spent with primary caregiver) in 62 middle-aged and older adults with Down syndrome (aged 30-53 years). Findings indicated that middle-aged and older adults with Down syndrome frequently participated in social and passive leisure…

  1. Extracurricular Activity and Parental Involvement Predict Positive Outcomes in Elementary School Children

    Science.gov (United States)

    Lagace-Seguin, Daniel G.; Case, Emily

    2010-01-01

    The main goal of this study was to explore if parental involvement and extracurricular activity participation could predict well-being and academic competence in elementary school children. Seventy-two children (mean age = 10.9 years, SD = 0.85) and their parents participated. Results revealed that parental pressure and support, when paired with…

  2. Premature aging in mice activates a systemic metabolic response involving autophagy induction

    NARCIS (Netherlands)

    G. Mariño (Guillermo); A.P. Ugalde (Alejandro); N. Salvador-Montoliu (Natalia); I. Varela (Ignacio); P.M. Quirós (Pedro); J. Cadiñanos (Juan); I. van der Pluijm (Ingrid); J.M.P. Freije (José); C. López-Otín (Carlos)

    2008-01-01

    textabstractAutophagy is a highly regulated intracellular process involved in the turnover of most cellular constituents and in the maintenance of cellular homeostasis. It is well-established that the basal autophagic activity of living cells decreases with age, thus contributing to the accumulation

  3. Active involvement of people with intellectual disabilities in health research - A structured literature review

    NARCIS (Netherlands)

    Frankena, T.K.; Naaldenberg, J.; Cardol, M.; Linehan, C.; Schrojenstein Lantman-de Valk, H.M. van

    2015-01-01

    Actively involving people with intellectual disabilities (ID) in health research, also known as inclusive health research, is increasingly popular. Currently, insight into experiences of this type of research is scarce. To gain insight into this topic, a structured literature review was conducted

  4. Beyond the Classroom: Involving Students with Disabilities in Extracurricular Activities at Levy Middle School.

    Science.gov (United States)

    Walker, Pam; And Others

    Six students in a special education classroom at Levy Middle School (Syracuse, New York) became involved in a variety of after-school activities with nondisabled students. The students participated in the school computer club, cross-country skiing, volleyball, stage crew, intramural basketball, the Spanish Club, and after-school programs at two…

  5. Critical role of ASC inflammasomes and bacterial type IV secretion system in caspase-1 activation and host innate resistance to Brucella abortus infection.

    Science.gov (United States)

    Gomes, Marco Tulio R; Campos, Priscila C; Oliveira, Fernanda S; Corsetti, Patricia P; Bortoluci, Karina R; Cunha, Larissa D; Zamboni, Dario S; Oliveira, Sergio C

    2013-04-01

    Pathogens are detected by innate immune receptors that, upon activation, orchestrate an appropriate immune response. Recent studies revealed the intracellular signaling cascades involved in the TLR-initiated immune response to Brucella abortus infection. However, no report has elucidated the role of inflammasome receptors in Brucella recognition. Therefore, we decided to investigate the function of NLRC4, NLRP3, and AIM2 in sensing Brucella. In this study, we showed that NLRC4 is not required to induce caspase-1 activation and further secretion of IL-1β by B. abortus in macrophages. In contrast, we determined that AIM2, which senses Brucella DNA, and NLRP3 are partially required for caspase-1 activation and IL-1β secretion. Additionally, mitochondrial reactive oxygen species induced by Brucella were implicated in IL-1β production. Furthermore, AIM2, NLRP3, ASC, and caspase-1 knockout mice were more susceptible to B. abortus infection than were wild-type animals, suggesting that multiple ASC-dependent inflammasomes contribute to host protection against infection. This protective effect is due to the inflammatory response caused by IL-1β and IL-18 rather than pyroptosis, because we observed augmented bacterial burden in IL-1R and IL-18 knockout mice. Finally, we determined that bacterial type IV secretion system VirB and live, but not heat-killed, Brucella are required for full inflammasome activation in macrophages during infection. Taken together, our results indicate that Brucella is sensed by ASC inflammasomes that collectively orchestrate a robust caspase-1 activation and proinflammatory response.

  6. Bacterial and fungal keratitis in Upper Egypt: In vitro screening of enzymes, toxins and antifungal activity

    Directory of Open Access Journals (Sweden)

    Abdullah A Gharamah

    2014-01-01

    Full Text Available Purpose: This work was conducted to study the ability of bacterial and fungal isolates from keratitis cases in Upper Egypt to produce enzymes, toxins, and to test the isolated fungal species sensitivity to some therapeutic agents. Materials and Methods: One hundred and fifteen patients clinically diagnosed to have microbial keratitis were investigated. From these cases, 37 bacterial isolates and 25 fungal isolates were screened for their ability to produce extra-cellular enzymes in solid media. In addition, the ability of fungal isolates to produce mycotoxins and their sensitivity to 4 antifungal agents were tested. Results: Protease, lipase, hemolysins, urease, phosphatase, and catalase were detected respectively in 48.65%, 37.84%, 59.46%, 43.24%, 67.57%, and 100% out of 37 bacterial isolates tested. Out of 25 fungal isolates tested during the present study, 80% were positive for protease, 84% for lipase and urease, 28% for blood hemolysis, and 100% for phosphatase and catalase enzymes. Thirteen fungal isolates were able to produce detectable amounts of 7 mycotoxins in culture medium (aflatoxins (B1, B2, G1, and G2, sterigmatocystin, fumagillin, diacetoxyscirpenol, zearalenone, T-2 toxin, and trichodermin. Among the antifungal agents tested in this study, terbinafine showed the highest effect against most isolates in vitro. Conclusion: In conclusion, the ability of bacterial and fungal isolates to produce extracellular enzymes and toxins may be aid in the invasion and destruction of eye tissues, which, in turn, lead to vision loss.

  7. Active Transport of Phosphorylated Carbohydrates Promotes Intestinal Colonization and Transmission of a Bacterial Pathogen.

    Directory of Open Access Journals (Sweden)

    Brandon Sit

    2015-08-01

    Full Text Available Efficient acquisition of extracellular nutrients is essential for bacterial pathogenesis, however the identities and mechanisms for transport of many of these substrates remain unclear. Here, we investigate the predicted iron-binding transporter AfuABC and its role in bacterial pathogenesis in vivo. By crystallographic, biophysical and in vivo approaches, we show that AfuABC is in fact a cyclic hexose/heptose-phosphate transporter with high selectivity and specificity for a set of ubiquitous metabolites (glucose-6-phosphate, fructose-6-phosphate and sedoheptulose-7-phosphate. AfuABC is conserved across a wide range of bacterial genera, including the enteric pathogens EHEC O157:H7 and its murine-specific relative Citrobacter rodentium, where it lies adjacent to genes implicated in sugar sensing and acquisition. C. rodentium ΔafuA was significantly impaired in an in vivo murine competitive assay as well as its ability to transmit infection from an afflicted to a naïve murine host. Sugar-phosphates were present in normal and infected intestinal mucus and stool samples, indicating that these metabolites are available within the intestinal lumen for enteric bacteria to import during infection. Our study shows that AfuABC-dependent uptake of sugar-phosphates plays a critical role during enteric bacterial infection and uncovers previously unrecognized roles for these metabolites as important contributors to successful pathogenesis.

  8. Active Transport of Phosphorylated Carbohydrates Promotes Intestinal Colonization and Transmission of a Bacterial Pathogen

    Science.gov (United States)

    Sit, Brandon; Crowley, Shauna M.; Bhullar, Kirandeep; Lai, Christine Chieh-Lin; Tang, Calvin; Hooda, Yogesh; Calmettes, Charles; Khambati, Husain; Ma, Caixia; Brumell, John H.; Schryvers, Anthony B.; Vallance, Bruce A.; Moraes, Trevor F.

    2015-01-01

    Efficient acquisition of extracellular nutrients is essential for bacterial pathogenesis, however the identities and mechanisms for transport of many of these substrates remain unclear. Here, we investigate the predicted iron-binding transporter AfuABC and its role in bacterial pathogenesis in vivo. By crystallographic, biophysical and in vivo approaches, we show that AfuABC is in fact a cyclic hexose/heptose-phosphate transporter with high selectivity and specificity for a set of ubiquitous metabolites (glucose-6-phosphate, fructose-6-phosphate and sedoheptulose-7-phosphate). AfuABC is conserved across a wide range of bacterial genera, including the enteric pathogens EHEC O157:H7 and its murine-specific relative Citrobacter rodentium, where it lies adjacent to genes implicated in sugar sensing and acquisition. C. rodentium ΔafuA was significantly impaired in an in vivo murine competitive assay as well as its ability to transmit infection from an afflicted to a naïve murine host. Sugar-phosphates were present in normal and infected intestinal mucus and stool samples, indicating that these metabolites are available within the intestinal lumen for enteric bacteria to import during infection. Our study shows that AfuABC-dependent uptake of sugar-phosphates plays a critical role during enteric bacterial infection and uncovers previously unrecognized roles for these metabolites as important contributors to successful pathogenesis. PMID:26295949

  9. Chemical composition and anti-bacterial activity of essential oil from ...

    African Journals Online (AJOL)

    Yomi

    2012-01-24

    Jan 24, 2012 ... The effects of pH and temperature on the anti-bacterial .... The lipids content was estimated by volume weight ratio. ... high purity helium; flow rate, 1 mL/min; split ratio, 1:20; injection volume ... The agar disc diffusion method (Luangtongkum et al., 2007) was .... The peaks in this area were mixture vibration.

  10. Antibacterial activity of plant extracts on foodborne bacterial pathogens and food spoilage bacteria

    Science.gov (United States)

    Bacterial foodborne diseases are caused by consumption of foods contaminated with bacteria and/or their toxins. In this study, we evaluated antibacterial properties of twelve different extracts including turmeric, lemon and different kinds of teas against four major pathogenic foodborne bacteria inc...

  11. Antibacterial activity of essential oils on Xanthomonas vesicatoria and control of bacterial spot in tomato

    Directory of Open Access Journals (Sweden)

    Gilvaine Ciavareli Lucas

    2012-03-01

    Full Text Available The objective of this work was to evaluate the effects of plant essential oils (EOs on the growth of Xanthomonas vesicatoria, on bacterial morphology and ultrastructure, and on the severity of tomato bacterial spot. EOs from citronella, clove, cinnamon, lemongrass, eucalyptus, thyme, and tea tree were evaluated in vitro at concentrations of 0.1, 1.0, 10, and 100% in 1.0% powdered milk. The effect of EOs, at 0.1%, on the severity of tomato bacterial spot was evaluated in tomato seedlings under greenhouse conditions. The effects of citronella, lemongrass, clove, and tea tree EOs, at 0.1%, on X. vesicatoria cells were evaluated by transmission electron microscopy. All EOs showed direct toxic effect on the bacteria at a 10%-concentration in vitro. Under greenhouse conditions, the EOs of clove, citronella, tea tree, and lemongrass reduced disease severity. EOs of clove and tea tree, and streptomycin sulfate promoted loss of electron-dense material and alterations in the cytoplasm, whereas EO of tea tree promoted cytoplasm vacuolation, and those of citronella, lemongrass, clove, and tea tree caused damage to the bacterial cell wall. The EOs at a concentration of 0.1% reduce the severity of the disease.

  12. Bacterial and fungal keratitis in Upper Egypt: in vitro screening of enzymes, toxins and antifungal activity.

    Science.gov (United States)

    Gharamah, Abdullah A; Moharram, Ahmed M; Ismail, Mady A; Al-Hussaini, Ashraf K

    2014-02-01

    This work was conducted to study the ability of bacterial and fungal isolates from keratitis cases in Upper Egypt to produce enzymes, toxins, and to test the isolated fungal species sensitivity to some therapeutic agents. One hundred and fifteen patients clinically diagnosed to have microbial keratitis were investigated. From these cases, 37 bacterial isolates and 25 fungal isolates were screened for their ability to produce extra-cellular enzymes in solid media. In addition, the ability of fungal isolates to produce mycotoxins and their sensitivity to 4 antifungal agents were tested. Protease, lipase, hemolysins, urease, phosphatase, and catalase were detected respectively in 48.65%, 37.84%, 59.46%, 43.24%, 67.57%, and 100% out of 37 bacterial isolates tested. Out of 25 fungal isolates tested during the present study, 80% were positive for protease, 84% for lipase and urease, 28% for blood hemolysis, and 100% for phosphatase and catalase enzymes. Thirteen fungal isolates were able to produce detectable amounts of 7 mycotoxins in culture medium (aflatoxins (B1, B2, G1, and G2), sterigmatocystin, fumagillin, diacetoxyscirpenol, zearalenone, T-2 toxin, and trichodermin). Among the antifungal agents tested in this study, terbinafine showed the highest effect against most isolates in vitro. In conclusion, the ability of bacterial and fungal isolates to produce extracellular enzymes and toxins may be aid in the invasion and destruction of eye tissues, which, in turn, lead to vision loss.

  13. Transcriptional activity around bacterial cell death reveals molecular biomarkers for cell viability

    NARCIS (Netherlands)

    Kort, R.; Keijser, B.J.; Caspers, M.P.M.; Schuren, F.H.; Montijn, R.

    2008-01-01

    Background: In bacteriology, the ability to grow in selective media and to form colonies on nutrient agar plates is routinely used as a retrospective criterion for the detection of living bacteria. However, the utilization of indicators for bacterial viability-such as the presence of specific

  14. Activation of the unfolded protein response is required for defenses against bacterial pore-forming toxin in vivo.

    Directory of Open Access Journals (Sweden)

    Larry J Bischof

    2008-10-01

    Full Text Available Pore-forming toxins (PFTs constitute the single largest class of proteinaceous bacterial virulence factors and are made by many of the most important bacterial pathogens. Host responses to these toxins are complex and poorly understood. We find that the endoplasmic reticulum unfolded protein response (UPR is activated upon exposure to PFTs both in Caenorhabditis elegans and in mammalian cells. Activation of the UPR is protective in vivo against PFTs since animals that lack either the ire-1-xbp-1 or the atf-6 arms of the UPR are more sensitive to PFT than wild-type animals. The UPR acts directly in the cells targeted by the PFT. Loss of the UPR leads to a normal response against unrelated toxins or a pathogenic bacterium, indicating its PFT-protective role is specific. The p38 mitogen-activated protein (MAPK kinase pathway has been previously shown to be important for cellular defenses against PFTs. We find here that the UPR is one of the key downstream targets of the p38 MAPK pathway in response to PFT since loss of a functional p38 MAPK pathway leads to a failure of PFT to properly activate the ire-1-xbp-1 arm of the UPR. The UPR-mediated activation and response to PFTs is distinct from the canonical UPR-mediated response to unfolded proteins both in terms of its activation and functional sensitivities. These data demonstrate that the UPR, a fundamental intracellular pathway, can operate in intrinsic cellular defenses against bacterial attack.

  15. Activation of the unfolded protein response is required for defenses against bacterial pore-forming toxin in vivo.

    Directory of Open Access Journals (Sweden)

    Larry J Bischof

    2008-10-01

    Full Text Available Pore-forming toxins (PFTs constitute the single largest class of proteinaceous bacterial virulence factors and are made by many of the most important bacterial pathogens. Host responses to these toxins are complex and poorly understood. We find that the endoplasmic reticulum unfolded protein response (UPR is activated upon exposure to PFTs both in Caenorhabditis elegans and in mammalian cells. Activation of the UPR is protective in vivo against PFTs since animals that lack either the ire-1-xbp-1 or the atf-6 arms of the UPR are more sensitive to PFT than wild-type animals. The UPR acts directly in the cells targeted by the PFT. Loss of the UPR leads to a normal response against unrelated toxins or a pathogenic bacterium, indicating its PFT-protective role is specific. The p38 mitogen-activated protein (MAPK kinase pathway has been previously shown to be important for cellular defenses against PFTs. We find here that the UPR is one of the key downstream targets of the p38 MAPK pathway in response to PFT since loss of a functional p38 MAPK pathway leads to a failure of PFT to properly activate the ire-1-xbp-1 arm of the UPR. The UPR-mediated activation and response to PFTs is distinct from the canonical UPR-mediated response to unfolded proteins both in terms of its activation and functional sensitivities. These data demonstrate that the UPR, a fundamental intracellular pathway, can operate in intrinsic cellular defenses against bacterial attack.

  16. Radiation-induced grafting of vinylbenzyltrimethylammonium chloride (VBT) onto cotton fabric and study of its anti-bacterial activities

    Science.gov (United States)

    Kumar, Virendra; Bhardwaj, Y. K.; Rawat, K. P.; Sabharwal, S.

    2005-06-01

    Mutual radiation grafting technique using 60Co gamma radiation has been used to carry out grafting of vinylbenzyltrimethylammonium chloride (VBT) onto cotton cellulose substrate. Grafting yield increased with radiation dose and decreased with dose rate but was adversely affected by the presence of O 2 and salts of Fe 2+ and Cu 2+. However, the presence of an acid did not affect grafting in the concentration range studied. The effect of organic solvents like methanol, ethanol, n-propanol, iso-propanol, tert-butanol on grafting yield was investigated in the mixed aqueous solvent system. The VBT grafted cotton samples showed significantly higher water uptake and water retention properties and possessed excellent anti-bacterial activity against strains like Escherichia coli and Staphylococcus aureus. Samples with 25% grafting extent showed 6 log cycles reduction in bacterial counts within 6 h of exposure time. The anti-bacterial activity of the grafted cotton samples was retained after several cycles of washing and drying in a commercial detergent powder.

  17. Different bulk and active bacterial communities in cryoconite from the margin and interior of the Greenland ice sheet

    DEFF Research Database (Denmark)

    Stibal, Marek; Nielsen, Morten Schostag; Cameron, Karen A.;

    2015-01-01

    composition of cryoconite over a melt season at two contrasting sites at the margin and in the interior of the Greenland ice sheet, using sequence analysis and quantitative polymerase chain reaction of coextracted 16S rDNA and rRNA. Significant differences were found between bulk (rDNA) and potentially active......Biological processes in the supraglacial ecosystem, including cryoconite, contribute to nutrient cycling within the cryosphere and may affect surface melting, yet little is known of the diversity of the active microbes in these environments. We examined the bacterial abundance and community...

  18. Salamander limb regeneration involves the activation of a multipotent skeletal muscle satellite cell population.

    Science.gov (United States)

    Morrison, Jamie I; Lööf, Sara; He, Pingping; Simon, András

    2006-01-30

    In contrast to mammals, salamanders can regenerate complex structures after injury, including entire limbs. A central question is whether the generation of progenitor cells during limb regeneration and mammalian tissue repair occur via separate or overlapping mechanisms. Limb regeneration depends on the formation of a blastema, from which the new appendage develops. Dedifferentiation of stump tissues, such as skeletal muscle, precedes blastema formation, but it was not known whether dedifferentiation involves stem cell activation. We describe a multipotent Pax7+ satellite cell population located within the skeletal muscle of the salamander limb. We demonstrate that skeletal muscle dedifferentiation involves satellite cell activation and that these cells can contribute to new limb tissues. Activation of salamander satellite cells occurs in an analogous manner to how the mammalian myofiber mobilizes stem cells during skeletal muscle tissue repair. Thus, limb regeneration and mammalian tissue repair share common cellular and molecular programs. Our findings also identify satellite cells as potential targets in promoting mammalian blastema formation.

  19. Exploring the active site of acyl homoserine lactones-dependent transcriptional regulators with bacterial quorum sensing modulators using molecular mechanics and docking studies.

    Science.gov (United States)

    Soulère, Laurent; Frezza, Marine; Queneau, Yves; Doutheau, Alain

    2007-09-01

    A comparative molecular modelling study of acyl homoserine lactones-dependent transcriptional regulators (TraR, SdiA, LuxR and LasR) involved in bacterial quorum sensing (QS) revealed a high structural homology of their active site. Docking studies within the active site of TraR of fixed conformations obtained using molecular mechanics calculations showed that TraR, for which the crystalline structure is known, is a relevant model for the study of other protein-ligand interactions in the same protein family. Structure-activity relationships of AHLs derived QS modulators including carboxamides, sulfonamides and ureas were thus investigated. The results show that Tyr61, a residue conserved in the LuxR-proteins family, is involved in attractive interactions with aromatic carboxamide antagonists. Tyr53, Tyr61 and Asp70, conserved residues, are implicated in both the development of additional hydrogen bonds and attractive interactions with the N-sulfonyl homoserine lactones and AHLs derived ureas antagonists.

  20. Personal Involvement with Learning Disability Children: Activities Groups Can Do for Personal Involvement with Learning Disability Children thru Movement Education.

    Science.gov (United States)

    Smith, Elizabeth I.

    Described are perceptual motor activities in the areas of coordination, agility, strength, balance, and endurance for use with learning disabled children. Provided are a rationale for movement education and definitions of 10 terms such as laterality and endurance. A sequence of activities is provided for the following skills: ball bouncing, rope…

  1. THE EXTERNAL FACTORS OF STUDENTS’ INVOLVEMENT IN SPEAKING ACTIVITY AT SMP PROGRESIF BUMI SHALAWAT

    Directory of Open Access Journals (Sweden)

    M.A. Nurul Haikal

    2016-07-01

    Full Text Available This research is conducted to know what factors that influence the students’ involvement in speaking activity in order to practice their speaking skill and what strategies that the teacher used to encourage those external factors. This research uses descriptive qualitative method. There are two instruments used for this research, namely, class observation and interview. Based on the results of class observation and interview, the researcher concludes that teacher factor gives the greatest impact on students’ involvement and the appropriate strategies can support those external factors.

  2. Embedding a Recovery Orientation into Neuroscience Research: Involving People with a Lived Experience in Research Activity.

    Science.gov (United States)

    Stratford, Anthony; Brophy, Lisa; Castle, David; Harvey, Carol; Robertson, Joanne; Corlett, Philip; Davidson, Larry; Everall, Ian

    2016-03-01

    This paper highlights the importance and value of involving people with a lived experience of mental ill health and recovery in neuroscience research activity. In this era of recovery oriented service delivery, involving people with the lived experience of mental illness in neuroscience research extends beyond their participation as "subjects". The recovery paradigm reconceptualises people with the lived experience of mental ill health as experts by experience. To support this contribution, local policies and procedures, recovery-oriented training for neuroscience researchers, and dialogue about the practical applications of neuroscience research, are required.

  3. Commensal Bacteria-Induced Inflammasome Activation in Mouse and Human Macrophages Is Dependent on Potassium Efflux but Does Not Require Phagocytosis or Bacterial Viability

    Science.gov (United States)

    Chen, Kejie; Shanmugam, Nanda Kumar N.; Pazos, Michael A.; Hurley, Bryan P.; Cherayil, Bobby J.

    2016-01-01

    Gut commensal bacteria contribute to the pathogenesis of inflammatory bowel disease, in part by activating the inflammasome and inducing secretion of interleukin-1ß (IL-1ß). Although much has been learned about inflammasome activation by bacterial pathogens, little is known about how commensals carry out this process. Accordingly, we investigated the mechanism of inflammasome activation by representative commensal bacteria, the Gram-positive Bifidobacterium longum subspecies infantis and the Gram-negative Bacteroides fragilis. B. infantis and B. fragilis induced IL-1ß secretion by primary mouse bone marrow-derived macrophages after overnight incubation. IL-1ß secretion also occurred in response to heat-killed bacteria and was only partly reduced when phagocytosis was inhibited with cytochalasin D. Similar results were obtained with a wild-type immortalized mouse macrophage cell line but neither B. infantis nor B. fragilis induced IL-1ß secretion in a mouse macrophage line lacking the nucleotide-binding/leucine-rich repeat pyrin domain containing 3 (NLRP3) inflammasome. IL-1ß secretion in response to B. infantis and B. fragilis was significantly reduced when the wild-type macrophage line was treated with inhibitors of potassium efflux, either increased extracellular potassium concentrations or the channel blocker ruthenium red. Both live and heat-killed B. infantis and B. fragilis also induced IL-1ß secretion by human macrophages (differentiated THP-1 cells or primary monocyte-derived macrophages) after 4 hours of infection, and the secretion was inhibited by raised extracellular potassium and ruthenium red but not by cytochalasin D. Taken together, our findings indicate that the commensal bacteria B. infantis and B. fragilis activate the NLRP3 inflammasome in both mouse and human macrophages by a mechanism that involves potassium efflux and that does not require bacterial viability or phagocytosis. PMID:27505062

  4. Antibacterial Activity of the Isolation Ethyl Acetate-Soluble Extract Noni Fruit (Morindra citrifolia L.) against Meat Bacterial Decay

    Science.gov (United States)

    Nugraheni, E. R.; Nurrakhman, M. B. E.; Munawaroh, H.; Saputri, L.

    2017-02-01

    Noni (Morindra citrifolia L.) is native to Indonesia which have medicinal properties. One of them as an antibacterial. This study aims to determine the antibacterial activity of isolates from the ethanol extract noni fruit to bacterial decay meat is Bacillus licheniformis, Klebsiella pneumonia, Bacillus alvei, Acinetobacter calcoaceticus, and Staphylococcus saprophyticus. The extraction process using the maceration method, and then made a partition by centrifugation ethyl acetate. Soluble part partition showed bacterial growth inhibition activity of the strong to very strong. Furthermore, the ethyl acetate soluble partition on preparative thin layer chromatography produced 5 isolates. Isolates obtained antibacterial activity test performed with a concentration of 20% and 30%. The results of antibacterial test against bacteria test isolates, showing isolates A can not inhibit the growth of bacteria, isolates B and C have medium activity and strong, isolates D and E isolates have activity against bacteria that were tested. MIC and MBC test results showed that the isolates B gives an inhibitory effect (bacteriostatic) against all bacteria. Content analysis of compounds by TLC using the reagents cerium (IV) sulfate indicates a phenol group. Isolates B contains a major compound which can be used as an antibacterial candidate in food preservation replace chemical preservatives.

  5. Definition of a Bidirectional Activity-Dependent Pathway Involving BDNF and Narp

    Directory of Open Access Journals (Sweden)

    Abigail Mariga

    2015-12-01

    Full Text Available One of the cardinal features of neural development and adult plasticity is the contribution of activity-dependent signaling pathways. However, the interrelationships between different activity-dependent genes are not well understood. The immediate early gene neuronal-activity-regulated pentraxin (NPTX2 or Narp encodes a protein that has been associated with excitatory synaptogenesis, AMPA receptor aggregation, and the onset of critical periods. Here, we show that Narp is a direct transcriptional target of brain-derived neurotrophic factor (BDNF, another highly regulated activity-dependent gene involved in synaptic plasticity. Unexpectedly, Narp is bidirectionally regulated by BDNF. Acute BDNF withdrawal results in downregulation of Narp, whereas transcription of Narp is greatly enhanced by BDNF. Furthermore, our results show that BDNF directly regulates Narp to mediate glutamatergic transmission and mossy fiber plasticity. Hence, Narp serves as a significant epistatic target of BDNF to regulate synaptic plasticity during periods of dynamic activity.

  6. Isolation of genes (nif/hup cosmids) involved in hydrogenase and nitrogenase activities in Rhizobium japonicum.

    Science.gov (United States)

    Hom, S S; Graham, L A; Maier, R J

    1985-03-01

    Recombinant cosmids containing a Rhizobium japonicum gene involved in both hydrogenase (Hup) and nitrogenase (Nif) activities were isolated. An R. japonicum gene bank utilizing broad-host-range cosmid pLAFR1 was conjugated into Hup- Nif- R. japonicum strain SR139. Transconjugants containing the nif/hup cosmid were identified by their resistance to tetracycline (Tcr) and ability to grow chemoautotrophically (Aut+) with hydrogen. All Tcr Aut+ transconjugants possessed high levels of H2 uptake activity, as determined amperometrically. Moreover, all Hup+ transconjugants tested possessed the ability to reduce acetylene (Nif+) in soybean nodules. Cosmid DNAs from 19 Hup+ transconjugants were transferred to Escherichia coli by transformation. When the cosmids were restricted with EcoRI, 15 of the 19 cosmids had a restriction pattern with 13.2-, 4.0-, 3.0-, and 2.5-kilobase DNA fragments. Six E. coli transformants containing the nif/hup cosmids were conjugated with strain SR139. All strain SR139 transconjugants were Hup+ Nif+. Moreover, one nif/hup cosmid was transferred to 15 other R. japonicum Hup- mutants. Hup+ transconjugants of six of the Hup- mutants appeared at a frequency of 1.0, whereas the transconjugants of the other nine mutants remained Hup-. These results indicate that the nif/hup gene cosmids contain a gene involved in both nitrogenase and hydrogenase activities and at least one and perhaps other hup genes which are exclusively involved in H2 uptake activity.

  7. Effects of transient temperature conditions on the divergence of activated sludge bacterial community structure and function.

    Science.gov (United States)

    Nadarajah, Nalina; Allen, D Grant; Fulthorpe, Roberta R

    2007-06-01

    The effect of temperature fluctuations on bacterial community structure and function in lab-scale sequencing batch reactors treating bleached kraft mill effluent was investigated. An increase in temperature from 30 to 45 degrees C caused shifts in both bacterial community structure and function. Triplicate reactors were highly similar for 40 days following startup. After the temperature shift, their community structure and function started to diverge from each other and from the control. A multi-response permutation procedure confirmed that the variability in community structure between transient and control reactors were greater than that among the triplicate transient reactors. The fact that these disturbances manifest themselves in different ways in apparently identical reactors suggests a high degree of variability between replicate systems.

  8. Antibacterial activity of some Indian ayurvedic preparations against enteric bacterial pathogens

    Directory of Open Access Journals (Sweden)

    D H Tambekar

    2011-01-01

    Full Text Available In Ayurveda, various herbal preparations are clinically used to prevent or cure infectious diseases. Herbal preparations such as Triphala churna, Hareetaki churna, Dashmula churna, Manjistadi churna, Sukhsarak churna, Ajmodadi churna, Shivkshar pachan churna, Mahasudarshan churna, Swadist Virechan churna and Pipramool churna were investigated by preparing their organic solvent extract for antibacterial potential against enteric bacterial pathogens such as Escherichia coli, Staphylococcus aureus, Enterobacter aerogenes, Pseudomonas aeruginosa, Bacillus subtilis, Klebsiella pneumoniae, Salmonella typhi, Staphylococcus epidermidis, Salmonella typhimurium and Proteus vulgaris, respectively. In the present study, Triphala churna, Hareetaki churna, Dashmula churna were potent antibacterial agents against S. epidermidis, P. vulgaris, S. aureus, E. coli, P. aeruginosa and S. typhi. The study supports the use of these herbal preparations not only as dietary supplements but also as agents to prevent or control enteric bacterial infections.

  9. Biotransformation of arsenite and bacterial aox activity in drinking water produced from surface water of floating houses: Arsenic contamination in Cambodia.

    Science.gov (United States)

    Chang, Jin-Soo

    2015-11-01

    The potential arsenite bioteansformation activity of arsenic was investigated by examining bacterial arsenic arsenite-oxidizing gene such as aoxS, aoxR, aoxA, aoxB, aoxC, and aoxD in high arsenic-contaminated drinking water produced from the surface water of floating houses. There is a biogeochemical cycle of activity involving arsenite oxidase aox system and the ars (arsenic resistance system) gene operon and aoxR leader gene activity in Alcaligenes faecalis SRR-11 and aoxS leader gene activity in Achromobacter xylosoxidans TSL-66. Batch experiments showed that SRR-11 and TSL-66 completely oxidized 1 mM of As (III) to As (V) within 35-40 h. The leaders of aoxS and aoxR are important for gene activity, and their effects in arsenic bioremediation and mobility in natural water has a significant ecological role because it allows arsenite oxidase in bacteria to control the biogeochemical cycle of arsenic-contaminated drinking water produced from surface water of floating houses. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Premature aging in mice activates a systemic metabolic response involving autophagy induction.

    Science.gov (United States)

    Mariño, Guillermo; Ugalde, Alejandro P; Salvador-Montoliu, Natalia; Varela, Ignacio; Quirós, Pedro M; Cadiñanos, Juan; van der Pluijm, Ingrid; Freije, José M P; López-Otín, Carlos

    2008-07-15

    Autophagy is a highly regulated intracellular process involved in the turnover of most cellular constituents and in the maintenance of cellular homeostasis. It is well-established that the basal autophagic activity of living cells decreases with age, thus contributing to the accumulation of damaged macromolecules during aging. Conversely, the activity of this catabolic pathway is required for lifespan extension in animal models such as Caenorhabditis elegans and Drosophila melanogaster. In this work, we describe the unexpected finding that Zmpste24-null mice, which show accelerated aging and are a reliable model of human Hutchinson-Gilford progeria, exhibit an extensive basal activation of autophagy instead of the characteristic decline in this process occurring during normal aging. We also show that this autophagic increase is associated with a series of changes in lipid and glucose metabolic pathways, which resemble those occurring in diverse situations reported to prolong lifespan. These Zmpste24(-/-) mice metabolic alterations are also linked to substantial changes in circulating blood parameters, such as leptin, glucose, insulin or adiponectin which in turn lead to peripheral LKB1-AMPK activation and mTOR inhibition. On the basis of these results, we propose that nuclear abnormalities causing premature aging in Zmpste24(-/-) mice trigger a metabolic response involving the activation of autophagy. However, the chronic activation of this catabolic pathway may turn an originally intended pro-survival strategy into a pro-aging mechanism and could contribute to the systemic degeneration and weakening observed in these progeroid mice.

  11. Barriers to involvement in physical activities of persons with mental illness.

    Science.gov (United States)

    Shor, Ron; Shalev, Anat

    2016-03-01

    Participating in physical activities could be essential for reducing the multiple risk factors for health problems that persons with severe mental illness (SMI) may suffer. However, people with SMI are significantly less active than the general population. To develop knowledge about factors related to the perceived barriers hindering this population's participation in physical activities and the benefits this participation would have, a study was conducted in Israel with 86 people with mental illness living in community mental health facilities prior to their participation in a health promotion program. A mixed method was implemented and included: a scale designed to measure participants' perceptions of the barriers to and benefits of involvement in physical activities; instruments focusing on bio-psycho-social factors that may affect the level of barriers experienced; and personal interviews. The findings revealed high ranking for accessibility barriers hindering the participation in physical activities. Bio-psycho-social factors stemming from the participants' mental health, such as level of depression, were correlated with higher ranking of accessibility barriers. Bio-psycho-social factors reflecting positive mental health and health, such as positive appraisal of body weight, were correlated with lower ranking of accessibility barriers. Other barriers may include organizational and broader systemic barriers in the mental health facilities where the participants reside. These findings illuminate the need to consider the unique challenges that persons with mental illness may face in any attempt to advance their involvement in physical activity.

  12. Structure of Arabidopsis thaliana 5-methylthioribose Kinase Reveals a More Occluded Active Site Than its Bacterial Homolog

    Energy Technology Data Exchange (ETDEWEB)

    Ku,S.; Cornell, K.; Howell, P.

    2007-01-01

    Metabolic variations exist between the methionine salvage pathway of humans and a number of plants and microbial pathogens. 5-Methylthioribose (MTR) kinase is a key enzyme required for methionine salvage in plants and many bacteria. The absence of a mammalian homolog suggests that MTR kinase is a good target for the design of specific herbicides or antibiotics. The structure of Arabidopsis thaliana MTR kinase co-crystallized with ATP?S and MTR has been determined at 1.9 Angstroms resolution. The structure is similar to B. subtilis MTR kinase and has the same protein kinase fold observed in other evolutionarily related protein kinase-like phosphotransferases. The active site is comparable between the two enzymes with the DXE-motif coordinating the nucleotide-Mg, the D238 of the HGD catalytic loop polarizing the MTR O1 oxygen, and the RR-motif interacting with the substrate MTR. Unlike its bacterial homolog, however, the Gly-rich loop (G-loop) of A. thaliana MTR kinase has an extended conformation, which shields most of the active site from solvent, a feature that resembles eukaryotic protein kinases more than the bacterial enzyme. The G- and W-loops of A. thaliana and B. subtilis MTR kinase adopt different conformations despite high sequence similarity. The ATP?S analog was hydrolyzed during the co-crystallization procedure, resulting in ADP in the active site. This suggests that the A. thaliana enzyme, like its bacterial homolog, may have significant ATPase activity in the absence of MTR. The structure of A. thaliana MTR kinase provides a template for structure-based design of agrochemicals, particularly herbicides whose effectiveness could be regulated by nutrient levels. Features of the MTR binding site offer an opportunity for a simple organic salt of an MTR analog to specifically inhibit MTR kinase.

  13. Bacterial pathogens activate a common inflammatory pathway through IFNλ regulation of PDCD4.

    Directory of Open Access Journals (Sweden)

    Taylor S Cohen

    Full Text Available The type III interferon (IFNλ receptor IL-28R is abundantly expressed in the respiratory tract and has been shown essential for host defense against some viral pathogens, however no data are available concerning its role in the innate immune response to bacterial pathogens. Staphylococcus aureus and Pseudomonas aeruginosa induced significant production of IFNλ in the lung, and clearance of these bacteria from the lung was significantly increased in IL-28R null mice compared to controls. Improved bacterial clearance correlated with reduced lung pathology and a reduced ratio of pro- vs anti-inflammatory cytokines in the airway. In human epithelial cells IFNλ inhibited miR-21 via STAT3 resulting in upregulation of PDCD4, a protein known to promote inflammatory signaling. In vivo 18 hours following infection with either pathogen, miR-21 was significantly reduced and PDCD4 increased in the lungs of wild type compared to IL-28R null mice. Infection of PDCD4 null mice with USA300 resulted in improved clearance, reduced pathology, and reduced inflammatory cytokine production. These data suggest that during bacterial pneumonia IFNλ promotes inflammation by inhibiting miR-21 regulation of PDCD4.

  14. Propionibacterium acnes Bacteriophages Display Limited Genetic Diversity and Broad Killing Activity against Bacterial Skin Isolates

    Science.gov (United States)

    Marinelli, Laura J.; Fitz-Gibbon, Sorel; Hayes, Clarmyra; Bowman, Charles; Inkeles, Megan; Loncaric, Anya; Russell, Daniel A.; Jacobs-Sera, Deborah; Cokus, Shawn; Pellegrini, Matteo; Kim, Jenny; Miller, Jeff F.; Hatfull, Graham F.; Modlin, Robert L.

    2012-01-01

    ABSTRACT Investigation of the human microbiome has revealed diverse and complex microbial communities at distinct anatomic sites. The microbiome of the human sebaceous follicle provides a tractable model in which to study its dominant bacterial inhabitant, Propionibacterium acnes, which is thought to contribute to the pathogenesis of the human disease acne. To explore the diversity of the bacteriophages that infect P. acnes, 11 P. acnes phages were isolated from the sebaceous follicles of donors with healthy skin or acne and their genomes were sequenced. Comparative genomic analysis of the P. acnes phage population, which spans a 30-year temporal period and a broad geographic range, reveals striking similarity in terms of genome length, percent GC content, nucleotide identity (>85%), and gene content. This was unexpected, given the far-ranging diversity observed in virtually all other phage populations. Although the P. acnes phages display a broad host range against clinical isolates of P. acnes, two bacterial isolates were resistant to many of these phages. Moreover, the patterns of phage resistance correlate closely with the presence of clustered regularly interspaced short palindromic repeat elements in the bacteria that target a specific subset of phages, conferring a system of prokaryotic innate immunity. The limited diversity of the P. acnes bacteriophages, which may relate to the unique evolutionary constraints imposed by the lipid-rich anaerobic environment in which their bacterial hosts reside, points to the potential utility of phage-based antimicrobial therapy for acne. PMID:23015740

  15. Saponaria officinalis L. extract: Surface active properties and impact on environmental bacterial strains.

    Science.gov (United States)

    Smułek, Wojciech; Zdarta, Agata; Pacholak, Amanda; Zgoła-Grześkowiak, Agnieszka; Marczak, Łukasz; Jarzębski, Maciej; Kaczorek, Ewa

    2017-02-01

    Plant-derived surfactants are characterised by low toxicity, high biodegradability and environmental compatibility. They therefore have many applications; for instance, they can be used in bioremediation to accelerate biodegradation processes, especially of hydrophobic pollutants. This paper analyses the properties of an extract from Saponaria officinalis L. containing saponins and its impact on bacterial strains isolated from soil, as well as its potential for application in hydrocarbon bioremediation. The tested extract from Saponaria officinalis L. contains gypsogenin, hederagenin, hydroxyhederagenin and quillaic acid aglycone structures and demonstrates good emulsification properties. Contact with the extract led to modification of bacterial cell surface properties. A decrease in cell surface hydrophobicity and an increase in membrane permeability were recorded in the experiments. An increase of up to 63% in diesel oil biodegradation was also recorded for Pseudomonas putida DA1 on addition of 1gL(-1) of saponins from Saponaria officinalis L. Saponaria extract showed no toxic impact on the tested environmental bacterial strains at the concentration used in the biodegradation process. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. College/school of pharmacy affiliation and community pharmacies' involvement in public health activities.

    Science.gov (United States)

    Westrick, Salisa C; Mount, Jeanine; Watcharadamrongkun, Suntaree

    2009-11-12

    To examine the relationship between pharmacy college/school affiliation and community pharmacies' involvement in immunization and emergency preparedness activities. Telephone interviews were completed with 1,704 community pharmacies randomly sampled from 17 states to determine the pharmacies' involvement in immunization promotion, vaccine distribution, in-house immunization delivery, and health emergency preparedness and response, affiliation with college/school of pharmacy, and selected pharmacy and public health-related characteristics. Pharmacy college/school-affiliated community pharmacies were more likely than non-affiliated pharmacies to participate in immunization and emergency preparedness when controlling for pharmacy characteristics. College/school affiliation generally became nonsignificant, however, when public health-related characteristics were included in the analysis. Affiliation with a college/school of pharmacy was related to community pharmacies' involvement in immunization and emergency preparedness.

  17. Understanding affluent adolescent adjustment: The interplay of parental perfectionism, perceived parental pressure, and organized activity involvement.

    Science.gov (United States)

    Randall, Edin T; Bohnert, Amy M; Travers, Lea V

    2015-06-01

    This cross-sectional study examined relations between affluent adolescent adjustment and culturally salient factors within parent-child relationship and extracurricular domain. Bootstrapping techniques evaluated mediated effects among parental perfectionism, perceived parental pressure, intensity of organized activity (OA) involvement, and adolescent adjustment (i.e., depressive and anxiety symptoms, life satisfaction) within a sample of 10th graders and their parents (n = 88 parent-child pairs) from four high schools in affluent communities. Findings indicated that adolescents with more perfectionistic parents perceived more parental pressure and experienced poorer adjustment. Results also demonstrated that affluent adolescents who perceived more parental pressure were more intensely involved in OAs, but that higher OA intensity was linked to better adjustment. Findings highlight the importance of considering parental perfectionism when understanding adolescent behaviors and psychological outcomes, confirm the negative direct effects of parental pressure on adjustment, and corroborate prior research dispelling that highly intense OA involvement is linked to adolescent maladjustment.

  18. Suppression of pancreatic carcinoma growth by activating peroxisome proliferator-activated receptor γ involves angiogenesis inhibition

    Institute of Scientific and Technical Information of China (English)

    Yu-Wei Dong; Xing-Peng Wang; Kai Wu

    2009-01-01

    AIM: To study the possible actions and mechanisms of peroxisome proliferator-activated receptor γ (PPARγ), a ligand-activated transcription factor, in pancreatic carcinogenesis,especially in angiogenesis.METHODS: Expressions of PPARγ and retinoid acid receptor (RXRα) were examined by reverse-transcription polymerase chain reaction (RT-PCR) with immunocytochemical staining. Pancreatic carcinoma cells, PANC-1,were treated either with 9-cis-RA, a ligand of RXRα,or with 15-deoxy-Δ12,14 prostaglandin J2(15d-PGJ2), a ligand of PPARγ, or both. Antiproliferative effect was evaluated by cell viability using methyltetrazolium (MTT) assay. A pancreatic carcinoma xenograft tumor model of nude mice was established by inoculating PANC-1 cells subcutaneously. Rosiglitazone, a specific ligand of PPARγ, was administered via water drinking in experimental group of nude mice. After 75 d, all mice were sacrificed. Expression of proliferating cell nuclear antigen (PCNA) in tumor tissue was examined with immunohistochemical staining. Expression of vascular endothelial growth factor (VEGF) mRNA in PANC-1 cells, which were treated with 15d-PGJ2 or 9-cis-RA at variousconcentrations or different duration, was detected by semi-quantitative RT-PCR. Effects of Rosiglitazone on changes of microvascular density (MVD) and VEGF expression were investigated in xenograft tumor tissue. Neovasculature was detected with immunohistochemistry staining labeled with anti-Ⅳ collagen antibody, and indicated by MVD.RESULTS: RT-PCR and immunocytochemical staining showed that PPARγ and RXRα were expressed in PANC-1 cells at both transcription level and translation level. MTT assay demonstrated that 15d-PGJ2, 9-cis-RA and their combination inhibited the growth of PANC-1 cells in a dose-dependent manner. 9-cis-RA had a combined inhibiting action with 15d-PGJ2 on the growth of pancreatic carcinoma. In vivo studies revealed that Rosiglitazone significantly suppressed the growth of pancreatic carcinoma

  19. Active Involvement of End Users When Developing Web-Based Mental Health Interventions

    Directory of Open Access Journals (Sweden)

    Derek de Beurs

    2017-05-01

    Full Text Available BackgroundAlthough many web-based mental health interventions are being released, the actual uptake by end users is limited. The marginal level of engagement of end users when developing these interventions is recognized as an important cause for uptake problems. In this paper, we offer our perceptive on how to improve user engagement. By doing so, we aim to stimulate a discourse on user involvement within the field of online mental health interventions.MethodsWe shortly describe three different methods (the expert-driven method, intervention mapping, and scrum that were currently used to develop web-based health interventions. We will focus to what extent the end user was involved in the developmental phase, and what the additional challenges were. In the final paragraph, lessons learned are summarized, and recommendations provided.ResultsEvery method seems to have its trade-off: if end users are highly involved, availability of end users and means become problematic. If end users are less actively involved, the product may be less appropriate for the end user. Other challenges to consider are the funding of the more active role of technological companies, and the time it takes to process the results of shorter development cycles.ConclusionThinking about user-centered design and carefully planning, the involvement of end users should become standard in the field of web-based (mental health. When deciding on the level of user involvement, one should balance the need for input from users with the availability of resources such as time and funding.

  20. Acidobacteria dominate the active bacterial communities of Arctic tundra with widely divergent winter-time snow accumulation and soil temperatures.

    Science.gov (United States)

    Männistö, Minna K; Kurhela, Emilia; Tiirola, Marja; Häggblom, Max M

    2013-04-01

    The timing and extent of snow cover is a major controller of soil temperature and hence winter-time microbial activity and plant diversity in Arctic tundra ecosystems. To understand how snow dynamics shape the bacterial communities, we analyzed the bacterial community composition of windswept and snow-accumulating shrub-dominated tundra heaths of northern Finland using DNA- and RNA-based 16S rRNA gene community fingerprinting (terminal restriction fragment polymorphism) and clone library analysis. Members of the Acidobacteria and Proteobacteria dominated the bacterial communities of both windswept and snow-accumulating habitats with the most abundant phylotypes corresponding to subdivision (SD) 1 and 2 Acidobacteria in both the DNA- and RNA-derived community profiles. However, different phylotypes within Acidobacteria were found to dominate at different sampling dates and in the DNA- vs. RNA-based community profiles. The results suggest that different species within SD1 and SD2 Acidobacteria respond to environmental conditions differently and highlight the wide functional diversity of these organisms even within the SD level. The acidic tundra soils dominated by ericoid shrubs appear to select for diverse stress-tolerant Acidobacteria that are able to compete in the nutrient poor, phenolic-rich soils. Overall, these communities seem stable and relatively insensitive to the predicted changes in the winter-time snow cover.

  1. In vitro and in vivo bactericidal activity of Vitex negundo leaf extract against diverse multidrug resistant enteric bacterial pathogens

    Institute of Scientific and Technical Information of China (English)

    Muhammad Kamruzzaman; S.M. Nayeemul Bari; Shah M. Faruque

    2013-01-01

    Objective: To investigate in vitro and in vivo antibacterial potentials of Vitex negundo (V. negundo) leaf extracts against diverse enteric pathogens. Methods: Water and methanol extracts of V. negundo leaves were evaluated against enteric bacterial pathogens by using standard disc diffusion, viable bacterial cell count methods, determination of minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC). Results: Methanol extract of V. negundo leaves showed potent antibacterial activity (inhibition zone: 9.9-22.6 mm, MIC:200-3 200 μg/mL, MBC: 200-6 400 μg/mL) against all the pathogenic enteric bacteria (Vibriocholerae , Vibrio parahaemolyticus, Vibrio mimicus, Echerichia coli, Shigella spps., and Aeromonas spps) tested. Methanol extract of V. negundo leaves showed potent bactericidal activity both in vitro laboratory conditions (MBC, 200-400 μg/mL) and in the intestinal environment (Dose, 1-2 mg/mL) of infant mice against pathogenic Vibrio cholerae, the major causative agent of cholera. Furthermore, assays using the mice cholera model showed that V. negundo methanol extract can protect mice from Vibrio cholerae infection and significantly decrease the mortality rate (P<0.0001). Conclusions: For the first time we showed that methanol extract of V. negundo leaves exhibited strong vibriocidal activity both in vitro and in vivo conditions. Therefore, it will be useful to identify and isolate the active compounds of this extract that could be a good alternative of antibiotics to treat cholera.

  2. Optimization of niosomes for enhanced antibacterial activity and reduced bacterial resistance: in vitro and in vivo evaluation.

    Science.gov (United States)

    Abdelaziz, Ahmed A; Elbanna, Tarek E; Sonbol, Fatma I; Gamaleldin, Noha M; El Maghraby, Gamal M

    2015-02-01

    The aim was to optimize norfloxacin niosomes for enhanced antibacterial activity and reduced bacterial resistance. Pseudomonas aeruginosa, a biofilm forming bacterium, was used as the test organism. Different norfloxacin niosomes were evaluated in vitro and in vivo, respectively, for antibacterial activity compared with aqueous drug solution. The influence of norfloxacin niosomes on biofilm formation was investigated. The interaction of niosomes with bacterial cells was also monitored using the scanning electron microscopy (SEM). The efficacy of niosomes depended on their composition. Standard niosomes of Span 60 and cholesterol were similar to drug solution. Incorporation of Tween 80, oleic acid (OA), OA/propylene glycol or lecithin produced fluid niosomes which reduced the MIC and inhibited biofilm formation compared with drug solution. Incorporation of a positively charged agent into fluid niosomes enhanced the antibacterial activity and reduced biofilm formation significantly. SEM showed evidence of vesicle adsorption to the bacteria with possible adhesion or fusion with the cell membrane. The in vivo skin model confirmed the in vitro results with optimum niosomes being more efficient than drug solution. Niosomes are promising for enhanced antibacterial activity and reduced resistance to antibiotics. The later can be achieved by inhibition of biofilm formation.

  3. Constitutively activated ERK sensitizes cancer cells to doxorubicin: Involvement of p53-EGFR-ERK pathway

    Indian Academy of Sciences (India)

    RATNA KUMARI; SURBHI CHOUHAN; SNAHLATA SINGH; RISHI RAJ CHHIPA; AMRENDRA KUMAR AJAY; MANOJ KUMAR BHAT

    2017-03-01

    The tumour suppressor gene p53 is mutated in approximately 50% of the human cancers. p53 is involved in genotoxicstress-induced cellular responses. The role of EGFR and ERK in DNA-damage-induced apoptosis is well known. Weinvestigated the involvement of activation of ERK signalling as a consequence of non-functional p53, in sensitivity ofcells to doxorubicin. We performed cell survival assays in cancer cell lines with varying p53 status: MCF-7 (wild-typep53, WTp53), MDA MB-468 (mutant p53, MUTp53), H1299 (absence of p53, NULLp53) and an isogenic cell lineMCF-7As (WTp53 abrogated). Our results indicate that enhanced chemosensitivity of cells lacking wild-type p53function is because of elevated levels of EGFR which activates ERK. Additionally, we noted that independent of p53status, pERK contributes to doxorubicin-induced cell death.

  4. Carbohydrate in the mouth enhances activation of brain circuitry involved in motor performance and sensory perception.

    Science.gov (United States)

    Turner, Clare E; Byblow, Winston D; Stinear, Cathy M; Gant, Nicholas

    2014-09-01

    The presence of carbohydrate in the human mouth has been associated with the facilitation of motor output and improvements in physical performance. Oral receptors have been identified as a potential mode of afferent transduction for this novel form of nutrient signalling that is distinct from taste. In the current study oral exposure to carbohydrate was combined with a motor task in a neuroimaging environment to identify areas of the brain involved in this phenomenon. A mouth-rinsing protocol was conducted whilst carbohydrate (CHO) and taste-matched placebo (PLA) solutions were delivered and recovered from the mouths of 10 healthy volunteers within a double-blind, counterbalanced design. This protocol eliminates post-oral factors and controls for the perceptual qualities of solutions. Functional magnetic resonance imaging of the brain was used to identify cortical areas responsive to oral carbohydrate during rest and activity phases of a hand-grip motor task. Mean blood-oxygen-level dependent signal change experienced in the contralateral primary sensorimotor cortex was larger for CHO compared with PLA during the motor task when contrasted with a control condition. Areas of activation associated with CHO exclusively were observed over the primary taste cortex and regions involved in visual perception. Regions in the limbic system associated with reward were also significantly more active with CHO. This is the first demonstration that oral carbohydrate signalling can increase activation within the primary sensorimotor cortex during physical activity and enhance activation of neural networks involved in sensory perception. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Mechanisms involved in VPAC receptors activation and regulation: lessons from pharmacological and mutagenesis studies.

    Directory of Open Access Journals (Sweden)

    Ingrid eLanger

    2012-10-01

    Full Text Available VIP plays diverse and important role in human physiology and physiopathology and their receptors constitute potential targets for the treatment of several diseases such as neurodegenerative disorder, asthma, diabetes and inflammatory diseases. This article reviews the current knowledge regarding the two VIP receptors, VPAC1 and VPAC2, with respect to mechanisms involved in receptor activation, G protein coupling, signaling, regulation and oligomerization.

  6. The influence of motivational involvement in physical activity level improving using formative evaluation procedures

    OpenAIRE

    Gonçalves, Francisco

    2014-01-01

    The current work was planned to build up an original motivational involvement, based on Self-Determination Theory and Social Cognitive Theory, to improving physical activity in disadvantaged adolescents. The theoretical structure has three main issues: social context (perceived independence, perceived social sustain, input and enjoyment); cognitive mediators (perceived option and self-efficacy); and motivational course (intrinsic motivation, commitment and positive self-concept). ...

  7. Activity and recovery cycles of National Rugby League matches involving higher and lower ranked teams.

    Science.gov (United States)

    Gabbett, Tim J

    2013-06-01

    This study investigated the influence of ladder position on ball-in-play and recovery periods in elite National Rugby League (NRL) competitive matches. Video recordings of 192 NRL matches and 18 NRL finals matches played over 2 competitive seasons were coded for activity and recovery cycles. Time when the ball was continuously in play was considered activity, whereas any stoppages during the match (e.g., for scrums, penalties, line drop outs, tries, and video referee decisions) were considered recovery. In comparison to matches involving lower standard teams, there was a greater proportion (effect size [ES] = 0.37-0.67) of long duration (>91 seconds) and a smaller proportion (ES = 0.49-0.68) of short duration (<45 seconds) ball-in-play periods when Top 4 teams were competing against other Top 4 teams. No meaningful differences were found between teams of different ladder positions for the proportion of short (ES = 0.04-0.16) and long (ES = 0.06-0.28) recovery periods. In comparison to fixture matches involving the top 4 teams, finals matches had a smaller proportion (ES = 0.56) of long duration activity periods, and a greater proportion (ES = 0.54) of short duration activity periods. Only small differences were found between finals matches and matches involving the Top 4 teams for the proportion of short (ES = 0.42) and long (ES = 0.41) recovery periods. These findings suggest that the competitive advantage of the best NRL teams is closely linked to their ability to maintain a higher playing intensity than less successful teams. Furthermore, long ball-in-play periods in high-standard fixture matches (i.e., involving the top 4 teams) ensure that players are adequately prepared for the ball-in-play demands of finals matches.

  8. Aluminum hydroxide adjuvant differentially activates the three complement pathways with major involvement of the alternative pathway.

    Science.gov (United States)

    Güven, Esin; Duus, Karen; Laursen, Inga; Højrup, Peter; Houen, Gunnar

    2013-01-01

    Al(OH)3 is the most common adjuvant in human vaccines, but its mode of action remains poorly understood. Complement involvement in the adjuvant properties of Al(OH)3 has been suggested in several reports together with a depot effect. It is here confirmed that Al(OH)3 treatment of serum depletes complement components and activates the complement system. We show that complement activation by Al(OH)3 involves the three major pathways by monitoring complement components in Al(OH)3-treated serum and in Al(OH)3-containing precipitates. Al(OH)3 activation of complement results in deposition of C3 cleavage products and membrane attack complex (MAC) and in generation of the anaphylatoxins C3a and C5a. Complement activation was time dependent and inhibited by chelation with EDTA but not EGTA+Mg(2+). We thus confirm that Al(OH)3 activates the complement system and show that the alternative pathway is of major importance.

  9. Aluminum hydroxide adjuvant differentially activates the three complement pathways with major involvement of the alternative pathway.

    Directory of Open Access Journals (Sweden)

    Esin Güven

    Full Text Available Al(OH3 is the most common adjuvant in human vaccines, but its mode of action remains poorly understood. Complement involvement in the adjuvant properties of Al(OH3 has been suggested in several reports together with a depot effect. It is here confirmed that Al(OH3 treatment of serum depletes complement components and activates the complement system. We show that complement activation by Al(OH3 involves the three major pathways by monitoring complement components in Al(OH3-treated serum and in Al(OH3-containing precipitates. Al(OH3 activation of complement results in deposition of C3 cleavage products and membrane attack complex (MAC and in generation of the anaphylatoxins C3a and C5a. Complement activation was time dependent and inhibited by chelation with EDTA but not EGTA+Mg(2+. We thus confirm that Al(OH3 activates the complement system and show that the alternative pathway is of major importance.

  10. Aluminum Hydroxide Adjuvant Differentially Activates the Three Complement Pathways with Major Involvement of the Alternative Pathway

    Science.gov (United States)

    Güven, Esin; Duus, Karen; Laursen, Inga; Højrup, Peter; Houen, Gunnar

    2013-01-01

    Al(OH)3 is the most common adjuvant in human vaccines, but its mode of action remains poorly understood. Complement involvement in the adjuvant properties of Al(OH)3 has been suggested in several reports together with a depot effect. It is here confirmed that Al(OH)3 treatment of serum depletes complement components and activates the complement system. We show that complement activation by Al(OH)3 involves the three major pathways by monitoring complement components in Al(OH)3-treated serum and in Al(OH)3-containing precipitates. Al(OH)3 activation of complement results in deposition of C3 cleavage products and membrane attack complex (MAC) and in generation of the anaphylatoxins C3a and C5a. Complement activation was time dependent and inhibited by chelation with EDTA but not EGTA+Mg2+. We thus confirm that Al(OH)3 activates the complement system and show that the alternative pathway is of major importance. PMID:24040248

  11. MR imaging in adults with Gaucher disease type I: evulation of marrow involvement and disease activity

    Energy Technology Data Exchange (ETDEWEB)

    Hermann, G. (Dept. of Radiology, Mount Sinai Medical Center, City Univ. of New York, NY (United States)); Shaprio, R.S. (Dept. of Radiology, Mount Sinai Medical Center, City Univ. of New York, NY (United States)); Abdelwahab, I.F. (Dept. of Radiology, Mount Sinai Medical Center, City Univ. of New York, NY (United States)); Grabowski, G. (Dept. of Pediatrics, Mount Sinai Medical Center, City Univ. of New York, NY (United States))

    1993-05-01

    An investigation was conducted to determine the usefulness of magnetic resonance imaging (MRI) in the evaluation of bone marrow involvement in patients with Gaucher disease type I. T1- and T2-weighted images were obtained of the lower extremities of 29 adult patients. Patients were classified into one of three groups based on marrow signal patterns on T1- and T2-weighted images as well as change in signal intensity from T1- to T2-weighted images. An increase in signal intensity from T1- to T2-weighted images was the criterion for an 'active process' within the bone marrow. Classification of the 29 patients produced the following results: Group A: Normal, 4 patients; group B: Marrow infiltration, 16 patients; group C: Marrow infiltration plus active marrow process, 9 patients. Correlation with clinical findings revealed that all nine patients with evidence of an active marrow process on MRI (group C) had acute bone pain. Conversely, only one of the remaining 20 patients (groups A and B) had bone pain. There was no correlation between disease activity and findings on conventional radiographs. We conclude the MRI provides an excellent noninvasive assessment of the extent and activity of marrow involvement in type I Gaucher disease. (orig.)

  12. Use of mass-media and active involvement in a national dental health campaign in Scotland

    DEFF Research Database (Denmark)

    Schou, L

    1987-01-01

    This paper describes the evaluation of a Dental Health Mass-Media Campaign directed at 5-7-yr-old children and their mothers. It aimed at increasing knowledge and awareness of dental health by making use of three different components: inserts in women's magazines; television commercial; material ...... that future national health education campaigns combine the mass-media approach to increase health awareness with active involvement activities to stimulate behavioural changes.......This paper describes the evaluation of a Dental Health Mass-Media Campaign directed at 5-7-yr-old children and their mothers. It aimed at increasing knowledge and awareness of dental health by making use of three different components: inserts in women's magazines; television commercial; material......, distinguished from the other two components by demanding an active involvement of the participants, had the largest impact. The television commercial, merely demanding a passive involvement of the participants, was less well remembered, and the magazine insert had the lowest recollection. It is suggested...

  13. XAS study of the active site of a bacterial heme-sensor

    Energy Technology Data Exchange (ETDEWEB)

    Della Longa, S [Dipartimento di Medicina Sperimentale, Universita dell' Aquila via Vetoio, loc. Coppito II 67100 L' Aquila (Italy); Arcovito, A [Istituto di Biochimica e Biochimica Clinica, Universita Cattolica del Sacro Cuore, Largo F. Vito 1, 00168, Roma (Italy); Brunori, M; Castiglione, N; Cutruzzola, F; Giardina, G; Rinaldo, S [Dipartimento di Scienze Biochimiche ' A. Rossi Fanelli' , Sapienza Universit/a di Roma, P. le A. Moro 5, 00185 Roma (Italy); D' Angelo, P, E-mail: dlonga@caspur.i [Dipartimento di Chimica, Sapienza Universita di Roma, P. le A.Moro 5, 00185 Roma (Italy)

    2009-11-15

    Denitrifying bacteria control NO and NO{sub 2} cytosolic levels by regulating the expression of denitrification gene clusters via REDOX signalling of specific transcriptional factors that may act as NO sensors in vivo. A protein belonging to the subclass DNR (dissimilative nitrate respiration regulator) from Pseudomonas aeruginosa has been recently suggested to be a heme containing protein. Very recently the three dimensional structure of the apo-form of DNR (in the absence of heme) has been determined by X-Ray crystallography, whereas the holo-form (in the presence of heme) has not yet been crystallized. We have investigated the heme local structure in solution of ferric and ferrous holo-DNR by XAS. The Fe K-edge XANES spectrum of the ferric adduct displays typical features of a low-spin hexacoordinate Fe-heme complex, having two histidines ligated. After chemical reduction, relevant changes of the XANES fingerprints suggest a repositioning of the heme inside the hydrophobic core of the protein in agreement with previously reported structural and spectroscopic evidence. Partial release of the axial ligands leaves the Fe(II)heme available, and very reactive, to bind exogenous ligands like NO, thus supporting its role as the cofactor involved in NO sensing activity.

  14. Development of a high-throughput method to evaluate serum bactericidal activity using bacterial ATP measurement as survival readout

    Science.gov (United States)

    Saul, Allan; Rondini, Simona

    2017-01-01

    Serum Bactericidal Activity (SBA) assay is the method of choice to evaluate the complement-mediated functional activity of both infection- and vaccine-induced antibodies. To perform a typical SBA assay, serial dilutions of sera are incubated with target bacterial strains and complement. The conventional SBA assay is based on plating on agar the SBA reaction mix and counting the surviving bacterial colony forming units (CFU) at each serum dilution. Even with automated colony counting, it is labor-intensive, time-consuming and not amenable for large-scale studies. Here, we have developed a luminescence-based SBA (L-SBA) method able to detect surviving bacteria by measuring their ATP. At the end of the SBA reaction, a single commercially available reagent is added to each well of the SBA plate, and the resulting luminescence signal is measured in a microplate reader. The signal obtained is proportional to the ATP present, which is directly proportional to the number of viable bacteria. Bactericidal activity is subsequently calculated. We demonstrated the applicability of L-SBA with multiple bacterial serovars, from 5 species: Citrobacter freundii, Salmonella enterica serovars Typhimurium and Enteritidis, Shigella flexneri serovars 2a and 3a, Shigella sonnei and Neisseria meningitidis. Serum bactericidal titers obtained by the luminescence readout method strongly correlate with the data obtained by the conventional agar plate-based assay, and the new assay is highly reproducible. L-SBA considerably shortens assay time, facilitates data acquisition and analysis and reduces the operator dependency, avoiding the plating and counting of CFUs. Our results demonstrate that L-SBA is a useful high-throughput bactericidal assay. PMID:28192483

  15. Lipoproteins attenuate TLR2 and TLR4 activation by bacteria and bacterial ligands with differences in affinity and kinetics.

    Science.gov (United States)

    van Bergenhenegouwen, Jeroen; Kraneveld, Aletta D; Rutten, Lieke; Garssen, Johan; Vos, Arjan P; Hartog, Anita

    2016-10-28

    The small intestine is a specialized compartment were close interactions take place between host, microbes, food antigens and dietary fatty acids. Dietary fats get absorbed by epithelial cells and processed into a range of lipoprotein particles after which they are basolaterally secreted and collected in the lymphatics. In contrast to the colon, the small intestine is covered only by a thin mucus coat that allows for intimate interactions between host-cells and microbes. Lipoproteins have long been recognized as protective factors in infectious diseases via the neutralization of bacterial toxins like lipopolysaccharides. Much less attention has been given to the potential role of lipoproteins as factors contributing to the maintenance of small intestinal immune homeostasis via modulating bacteria-induced immune responses. Lipoproteins VLDL, LDL and HDL were found to neutralize TLR responses towards specific TLR-ligands or a selection of gram-negative and gram-positive bacteria. Attenuation of TLR2 activity was acute and only slightly improved by longer pre-incubation times of ligands and lipoproteins with no differences between bacterial-lipopeptides or bacteria. In contrast, attenuation of TLR4 responses was only observed after extensive preincubation of lipoproteins and LPS. Preincubation of bacteria and lipoproteins led only to a modest attenuation of TLR4 activity. Moreover, compared to TLR2, TLR4 activity could only be attenuated by lipoproteins over a small ligand dose range. These results demonstrate the ability of lipoproteins VLDL, LDL and HDL to inhibit TLR responses towards bacterial-ligands and bacteria. Presence of lipoproteins was found to modulate the MAMP-induced cytokine release by primary human monocytes measured as changes in the release of IL-6, TNFα, GM-CSF and IFNγ. Using TLR2 and TLR4-reporter cells, lipoproteins were found to inhibit TLR responses with differences in affinity and kinetics. These data establish a role for lipoproteins as

  16. The bacterial effector HopX1 targets JAZ transcriptional repressors to activate jasmonate signaling and promote infection in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Selena Gimenez-Ibanez

    2014-02-01

    Full Text Available Pathogenicity of Pseudomonas syringae is dependent on a type III secretion system, which secretes a suite of virulence effector proteins into the host cytoplasm, and the production of a number of toxins such as coronatine (COR, which is a mimic of the plant hormone jasmonate-isoleuce (JA-Ile. Inside the plant cell, effectors target host molecules to subvert the host cell physiology and disrupt defenses. However, despite the fact that elucidating effector action is essential to understanding bacterial pathogenesis, the molecular function and host targets of the vast majority of effectors remain largely unknown. Here, we found that effector HopX1 from Pseudomonas syringae pv. tabaci (Pta 11528, a strain that does not produce COR, interacts with and promotes the degradation of JAZ proteins, a key family of JA-repressors. We show that hopX1 encodes a cysteine protease, activity that is required for degradation of JAZs by HopX1. HopX1 associates with JAZ proteins through its central ZIM domain and degradation occurs in a COI1-independent manner. Moreover, ectopic expression of HopX1 in Arabidopsis induces the expression of JA-dependent genes, represses salicylic acid (SA-induced markers, and complements the growth of a COR-deficient P. syringae pv. tomato (Pto DC3000 strain during natural bacterial infections. Furthermore, HopX1 promoted susceptibility when delivered by the natural type III secretion system, to a similar extent as the addition of COR, and this effect was dependent on its catalytic activity. Altogether, our results indicate that JAZ proteins are direct targets of bacterial effectors to promote activation of JA-induced defenses and susceptibility in Arabidopsis. HopX1 illustrates a paradigm of an alternative evolutionary solution to COR with similar physiological outcome.

  17. Anti-Pseudomonas aeruginosa IgY antibodies promote bacterial opsonization and augment the phagocytic activity of polymorphonuclear neutrophils

    DEFF Research Database (Denmark)

    Thomsen, Kim; Christophersen, Lars; Jensen, Peter Østrup

    2016-01-01

    Moderation of polymorphonuclear neutrophils (PMNs) as part of a critical defense against invading pathogens may offer a promising therapeutic approach to supplement the antibiotic eradication of Pseudomonas aeruginosa infection in non-chronically infected cystic fibrosis (CF) patients. We have...... observed that egg yolk antibodies (IgY) harvested from White leghorn chickens that target P. aeruginosa opsonize the pathogen and enhance the PMN-mediated respiratory burst and subsequent bacterial killing in vitro. The effects on PMN phagocytic activity were observed in different Pseudomonas aeruginosa...

  18. Involvement of serotonin 2A receptor activation in modulating medial prefrontal cortex and amygdala neuronal activation during novelty-exposure

    DEFF Research Database (Denmark)

    Hervig, Mona El-Sayed; Jensen, Nadja Cecilie Hvid; Rasmussen, Nadja Bredo

    2017-01-01

    -field arena affects medial PFC activation and basolateral amygdala (BLA) reactivity. We used c-Fos immunoreactivity (IR) as a marker of neuronal activation and stereological quantification for obtaining the total number of c-Fos-IR neurons as a measure of regional activation. We further examined the impact...... of 5-HT2AR blockade on the striatal-projecting BLA neurons. Systemic administration of ketanserin (0.5 mg/kg) prior to novel open-field exposure resulted in reduced total numbers of c-Fos-IR cells in dorsomedial PFC areas and the BLA. Moreover, there was a positive correlation between the relative time......-treated animals, upholding its involvement in modulating averseness. Ketanserin did not affect the number of activated striatal-projecting BLA neurons (measured by number of Cholera Toxin b (CTb) retrograde labelled neurons also being c-Fos-IR) following CTb injection in the ventral striatum. These results...

  19. Larvicidal Activities of Indigenous Bacillus thuringiensis Isolates and Nematode Symbiotic Bacterial Toxins against the Mosquito Vector, Culex pipiens (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Ashraf M Ahmed

    2017-06-01

    Full Text Available Background: The incidence of mosquito-borne diseases and the resistance of mosquitoes to conventional pesticides have recently caused a panic to the authorities in the endemic countries. This study was conducted to identify native larvicidal biopesticides against Culex pipiens for utilization in the battle against mosquito-borne diseases.Methods: Larvicidal activities of new indigenous Bacillus thuringiensis isolates and crude toxin complexes (TCs of two nematode bacterial-symbionts, Photorhabdus luminescens akhurstii (HRM1 and Ph. luminescens akhurstii (HS1 that tested against Cx. pipiens. B. thuringiensis isolates were recovered from different environmental samples in Saudi Arabia, and the entomopathogenic nematodes, Heterorhabditis indica (HRM1 and He. sp (HS1 were iso­lated from Egypt. Larvicidal activities (LC50 and LC95 of the potentially active B. thuringiensis strains or TCs were then evaluated at 24 and 48h post-treatment.Results: Three B. thuringiensis isolates were almost as active as the reference B. thuringiensis israelensis (Bti-H14, and seven isolates were 1.6–5.4 times more toxic than Bti-H14. On the other hand, the TCs of the bacterial sym­bionts, HRM1 and HS1, showed promising larvicidal activities. HS1 showed LC50 of 2.54 folds that of HRM1 at 24h post-treatment. Moreover, histopathological examinations of the HS1-treated larvae showed deformations in midgut epithelial cells at 24h post-treatment.Conclusion: Synergistic activity and molecular characterization of these potentially active biocontrol agents are currently being investigated. These results may lead to the identification of eco-friend mosquito larvicidal product(s that could contribute to the battle against mosquito-borne diseases.

  20. The bacterial elicitor flagellin activates its receptor in tomato cells according to the address-message concept.

    Science.gov (United States)

    Meindl, T; Boller, T; Felix, G

    2000-09-01

    flg22, a peptide corresponding to the most conserved domain of bacterial flagellin, acts as a potent elicitor in plants. Here, we have used an iodinated derivative of flg22 ((125)I-labeled Tyr-flg22) as a molecular probe for the flagellin receptor in tomato cells. This radioligand showed rapid binding to a single class of specific, saturable, high-affinity receptor sites in intact cells and membrane preparations. Binding, although essentially nonreversible under physiological conditions, was not covalent, and chemical cross-linking was required to specifically label a single polypeptide of 115 kD. Intact flagellin and elicitor-active flagellin peptides but not biologically inactive analogs efficiently competed for binding of radioligand. Peptides lacking the C terminus of the conserved domain, previously found to act as competitive antagonists of elicitor action in tomato cells, also competed for binding of radioligand. Thus, this novel, high-affinity binding site exhibited all the characteristics expected of a functional receptor of bacterial flagellin. For a model of receptor activation, we propose a two-step mechanism according to the address-message concept, in which binding of the N terminus (address) is the first step and activation of responses with the C terminus (message) is the second step.

  1. Vertical distribution of bacterial community is associated with the degree of soil organic matter decomposition in the active layer of moist acidic tundra.

    Science.gov (United States)

    Kim, Hye Min; Lee, Min Jin; Jung, Ji Young; Hwang, Chung Yeon; Kim, Mincheol; Ro, Hee-Myong; Chun, Jongsik; Lee, Yoo Kyung

    2016-11-01

    The increasing temperature in Arctic tundra deepens the active layer, which is the upper layer of permafrost soil that experiences repeated thawing and freezing. The increasing of soil temperature and the deepening of active layer seem to affect soil microbial communities. Therefore, information on soil microbial communities at various soil depths is essential to understand their potential responses to climate change in the active layer soil. We investigated the community structure of soil bacteria in the active layer from moist acidic tundra in Council, Alaska. We also interpreted their relationship with some relevant soil physicochemical characteristics along soil depth with a fine scale (5 cm depth interval). The bacterial community structure was found to change along soil depth. The relative abundances of Acidobacteria, Gammaproteobacteria, Planctomycetes, and candidate phylum WPS-2 rapidly decreased with soil depth, while those of Bacteroidetes, Chloroflexi, Gemmatimonadetes, and candidate AD3 rapidly increased. A structural shift was also found in the soil bacterial communities around 20 cm depth, where two organic (upper Oi and lower Oa) horizons are subdivided. The quality and the decomposition degree of organic matter might have influenced the bacterial community structure. Besides the organic matter quality, the vertical distribution of bacterial communities was also found to be related to soil pH and total phosphorus content. This study showed the vertical change of bacterial community in the active layer with a fine scale resolution and the possible influence of the quality of soil organic matter on shaping bacterial community structure.

  2. Involvement of the Sinorhizobium meliloti leuA gene in activation of nodulation genes by NodD1 and luteolin.

    Science.gov (United States)

    Sanjuán-Pinilla, Julio M; Muñoz, Socorro; Nogales, Joaquina; Olivares, José; Sanjuán, Juan

    2002-07-01

    The role of leucine biosynthesis by Sinorhizobium meliloti in the establishment of nitrogen-fixing symbiosis with alfalfa ( Medicago sativa) was investigated. The leuA gene from S. meliloti, encoding alpha-isopropylmalate synthase, which catalyses the first specific step in the leucine biosynthetic pathway, was characterized. S. melilotiLeuA(-) mutants were Leu auxotrophs and lacked alpha-isopropylmalate synthase activity. In addition, leuA auxotrophs were unable to nodulate alfalfa. Alfalfa roots did not seem to secrete enough leucine to support growth of leucine auxotrophs in the rhizosphere. Thus, this growth limitation probably imposes the inability to initiate symbiosis. However, in addition to the leucine auxotrophy, leuA strains were impaired in activation of nodulation genes by the transcriptional activator NodD1 in response to the plant flavone luteolin. By contrast, nod gene activation by NodD3, which does not involve plant-derived inducers, was unaffected. Our results suggest that a leucine-related metabolic intermediate may be involved in activation of nodulation genes by NodD1 and luteolin. This kind of control could be of relevance as a way to link bacterial physiological status to the response to plant signals and initiation of symbiosis.

  3. Beyond participation: the association between school extracurricular activities and involvement in violence across generations of immigration.

    Science.gov (United States)

    Jiang, Xin; Peterson, Ruth D

    2012-03-01

    Participation in extracurricular activities is purported to protect the broad spectrum of youth from a host of behavioral risks. Yet, empirical research on the extent to which this assumption holds for involvement in violence by immigrant youth is limited. Thus, using data for 13,236 (51.8% female) adolescents from the National Longitudinal Study of Adolescent Health, this study explores how the relationship between extracurricular activities and youth violence varies by type of extracurricular activity profile (sports alone, non-sports alone, and a combination of sports and non-sports) and by generations of immigration (first, second, and third-plus). The sample is composed of 9.3% (n = 1,233) first-generation youth, 15.7% (n = 2,080) second generation, and 74.9% (n = 9,923) third-plus generation. The results reveal that adolescents from the third-plus generation (i.e., non-immigrant youth) who participate in non-sports alone or sports plus non-sports have lower odds of involvement in violence than adolescents from the same generation who do not participate in extracurricular activities. However, for first- and second-generation adolescents, participation in extracurricular activities is associated with higher rather than lower odds of violence compared to their non-participating counterparts. These findings challenge the viewpoint that participation in mainstream extracurricular activities as afforded by US schools is equally beneficial for all youth. They also call for additional research that explores why immigrant youth are less likely than non-immigrant youth to gain violence-reducing benefits when they participate in extracurricular activities.

  4. Cholinesterase Activity in Health Workers Involved in Handling and Spraying of Organophosphorous Insecticides

    Directory of Open Access Journals (Sweden)

    Himanshu Madaan

    2011-04-01

    Full Text Available Background: Recent era of agricultural boon is partially the result of extensive use of insecticides and pesticides. But these compounds also have potential to significantly alter the ecosystem and can cause acute poisonings as well as long term detrimental health effects in humans. These compounds can cause toxicity through all routes of exposure. They exert their effect mainly by the inhibition of Acetylcholinesterase (AC hE, which functions by removing acetylcholine (AC h from its postsynaptic receptors. Aims and Objectives: Human exposure to Organophosphorous (OP pesticides can develop lowered cholinesterase levels. The aim of the present study was to estimate the plasma levels of AC hE in personnel involved in handling of these compounds, during the period of active spraying operations. Methodology: The present study was conducted on 38 subjects working as Multipurpose Health Workers (MPHW GROUP-1 and Field Workers (FW GROUP-2 involved in the actual spraying of the insecticides, in District Rohtak, Haryana, India to see the effect of exposure to OP insecticides. Plasma cholinesterase activity was measured by a kinetic method based on hydrolysis of butrylthiocholine. The data was statistically analyzed using SPSS statistical package (SPSS version 5.0. Results and interpretation: The mean cholinesterase activity in group-2 was lower by 27.76% than that in group-1 and this difference was statistically significant (p < 0.05. The workers involved in actual spraying of the insecticides had a more marked reduction in the levels of Plasma AC hE, compared to the workers involved only in the handling of the insecticides indicating that this group is at a bigger risk.

  5. Connecting the dots between bacterial biofilms and ice cream

    Science.gov (United States)

    Stanley-Wall, Nicola R.; MacPhee, Cait E.

    2015-12-01

    Emerging research is revealing a diverse array of interfacially-active proteins that are involved in varied biological process from foaming horse sweat to bacterial raincoat formation. We describe an interdisciplinary approach to study the molecular and biophysical mechanisms controlling the activity of an unusual bacterial protein called BslA. This protein is needed for biofilm formation and forms a protective layer or raincoat over the bacterial community, but also has a multitude of potential applications in multiphase formulations. Here we document our journey from fundamental research to an examination of the applications for this surface-active protein in ice cream.

  6. Bacterial Community Structure after Long-term Organic and Inorganic Fertilization Reveals Important Associations between Soil Nutrients and Specific Taxa Involved in Nutrient Transformations

    Science.gov (United States)

    Li, Fang; Chen, Lin; Zhang, Jiabao; Yin, Jun; Huang, Shaomin

    2017-01-01

    Fertilization has a large impact on the soil microbial communities, which play pivotal roles in soil biogeochemical cycling and ecological processes. While the effects of changes in nutrient availability due to fertilization on the soil microbial communities have received considerable attention, specific microbial taxa strongly influenced by long-term organic and inorganic fertilization, their potential effects and associations with soil nutrients remain unclear. Here, we use deep 16S amplicon sequencing to investigate bacterial community characteristics in a fluvo-aquic soil treated for 24 years with inorganic fertilizers and organics (manure and straw)-inorganic fertilizers, and uncover potential links between soil nutrient parameters and specific bacterial taxa. Our results showed that combined organic-inorganic fertilization increased soil organic carbon (SOC) and total nitrogen (TN) contents and altered bacterial community composition, while inorganic fertilization had little impact on soil nutrients and bacterial community composition. SOC and TN emerged as the major determinants of community composition. The abundances of specific taxa, especially Arenimonas, Gemmatimonas, and an unclassified member of Xanthomonadaceae, were substantially increased by organic-inorganic amendments rather than inorganic amendments only. A co-occurrence based network analysis demonstrated that SOC and TN had strong positive associations with some taxa (Gemmatimonas and the members of Acidobacteria subgroup 6, Myxococcales, Betaproteobacteria, and Bacteroidetes), and Gemmatimonas, Flavobacterium, and an unclassified member of Verrucomicrobia were identified as the keystone taxa. These specific taxa identified above are implicated in the decomposition of complex organic matters and soil carbon, nitrogen, and phosphorus transformations. The present work strengthens our current understanding of the soil microbial community structure and functions under long-term fertilization

  7. Evidence for a Symbiosis Island Involved in Horizontal Acquisition of Pederin Biosynthetic Capabilities by the Bacterial Symbiont of Paederus fuscipes Beetles

    OpenAIRE

    Piel, Jörn; Höfer, Ivonne; Hui, Dequan

    2004-01-01

    Pederin belongs to a group of antitumor compounds found in terrestrial beetles and marine sponges. It is used by apparently all members of the rove beetle genera Paederus and Paederidus as a chemical defense against predators. However, a recent analysis of the putative pederin biosynthesis (ped) gene cluster strongly suggests that pederin is produced by bacterial symbionts. We have sequenced an extended region of the symbiont genome to gain further insight into the biology of this as-yet-uncu...

  8. K⁺ efflux is the common trigger of NLRP3 inflammasome activation by bacterial toxins and particulate matter.

    Science.gov (United States)

    Muñoz-Planillo, Raúl; Kuffa, Peter; Martínez-Colón, Giovanny; Smith, Brenna L; Rajendiran, Thekkelnaycke M; Núñez, Gabriel

    2013-06-27

    The NLRP3 inflammasome is an important component of the innate immune system. However, its mechanism of activation remains largely unknown. We show that NLRP3 activators including bacterial pore-forming toxins, nigericin, ATP, and particulate matter caused mitochondrial perturbation or the opening of a large membrane pore, but this was not required for NLRP3 activation. Furthermore, reactive oxygen species generation or a change in cell volume was not necessary for NLRP3 activation. Instead, the only common activity induced by all NLRP3 agonists was the permeation of the cell membrane to K⁺ and Na⁺. Notably, reduction of the intracellular K⁺ concentration was sufficient to activate NLRP3, whereas an increase in intracellular Na⁺ modulated but was not strictly required for inflammasome activation. These results provide a unifying model for the activation of the NLRP3 inflammasome in which a drop in cytosolic K⁺ is the common step that is necessary and sufficient for caspase-1 activation. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Antinociceptive Activity of Methanol Extract of Muntingia calabura Leaves and the Mechanisms of Action Involved

    Directory of Open Access Journals (Sweden)

    M. H. Mohd. Sani

    2012-01-01

    Full Text Available Muntingia calabura L. (family Elaeocarpaceae has been traditionally used to relieve various pain-related ailments. The present study aimed to determine the antinociceptive activity of methanol extract of M. calabura leaves (MEMC and to elucidate the possible mechanism of antinociception involved. The in vivo chemicals (acetic acid-induced abdominal constriction and formalin-, capsaicin-, glutamate-, serotonin-induced paw licking test and thermal (hot plate test models of nociception were used to evaluate the extract antinociceptive activity. The extract (100, 250, and 500 mg/kg was administered orally 60 min prior to subjection to the respective test. The results obtained demonstrated that MEMC produced significant (P<0.05 antinociceptive response in all the chemical- and thermal-induced nociception models, which was reversed after pretreatment with 5 mg/kg naloxone, a non-selective opioid antagonist. Furthermore, pretreatment with L-arginine (a nitric oxide (NO donor, NG-nitro-L-arginine methyl esters (L-NAME; an inhibitor of NO synthase (NOS, methylene blue (MB; an inhibitor of cyclic-guanosine monophosphate (cGMP pathway, or their combination also caused significant (P<0.05 change in the intensity of the MEMC antinociception. In conclusion, the MEMC antinociceptive activity involves activation of the peripheral and central mechanisms, and modulation via, partly, the opioid receptors and NO/cGMP pathway.

  10. PRELIMINARY PHYTOCHEMICAL, ANTI-BACTERIAL, ANALGESIC, ANTI-DIARRHOEAL AND CYTOTOXIC ACTIVITY OF METHANOLIC EXTRACT OF POLYALTHIA SUBEROSA LEAVES

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    S.M. Moazzem Hossen et al.

    2012-05-01

    Full Text Available The MeOH extract of leaves of Polyalthia suberosa Roxb. (Annonaceae was screened for its antibacterial, analgesic, Antidiarrhoeal and cytotoxic activities. The extract showed moderate anti-bacterial activity against Vibrio cholerae, Sheigella sonnei, Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus saprophyticus. It also produced significant (P<0.01 writhing inhibition in acetic acid induced writhing in mice at dose of 250 and 500 mg/kg, which was comparable to the standard drug diclofenac sodium. Moreover, when tested for its antidiarrhoeal effects on castor oil induced diarrhea in mice, it decreased the frequency of defecation and increased mean latent period significantly (P<0.01 at the dose of 500 mg/kg comparable to the standard drug loperamide. The extract also exhibited high level of cytotoxicity in brine shrimp lethality bioassay (LC50: 30 µg/ml. The overall results tend to suggest the antibacterial, analgesic, antidiarrhoeal and cytotoxic activities of the extract.

  11. Effect of transportation on fecal bacterial communities and fermentative activities in horses: impact of Saccharomyces cerevisiae CNCM I-1077 supplementation.

    Science.gov (United States)

    Faubladier, C; Chaucheyras-Durand, F; da Veiga, L; Julliand, V

    2013-04-01

    This study evaluated the effect of transportation on fecal bacterial communities and activities in horses with or without supplementation of live yeast and attempted to link those effects with changes in blood stress markers. Four mature horses were assigned to a crossover design and fed a basal diet (60:40 forage to concentrate; 1.45% BW on a DM basis), with or without supplementation, of 2 × 10(10) cfu/d of Saccharomyces cerevisiae CNCM I-1077. After a 14-d adaptation to dietary treatments, the 5-d experiment started 1 d before transportation (d -1). At d 0, horses were simultaneously transported in a truck for 2 h. Feces were sampled 4 h after the morning meal of concentrate at d -1, 0 (immediately after transportation), and 3 for enumeration of the main functional bacterial groups and determination of fermentative variables. Within each dietary treatment, feces were pooled before DNA extraction and molecular analysis of the bacterial communities, using temporal temperature gradient electrophoreses (TTGE). Blood samples were collected at the same time for determination of white blood cells (WBC) counts and glucose and total protein concentrations. Regardless of dietary treatment, the neutrophil to lymphocyte ratio increased during transportation (P horses were stressed. In both treatments, TTGE profiles were clearly different before and 3 d after transportation, and the percentage of similarity between profiles at d -1 and 3 was greater in supplemented horses compared with the controls. From d 0 to 3, the molar percentage of propionate increased and total concentration of VFA and the acetate + butyrate to propionate ratio decreased, regardless of dietary treatment (P horses (P = 0.03). Regardless of day of sampling, fecal concentrations of lactate-utilizing bacteria and cellulolytic bacteria were greater in supplemented horses than in control horses (P = 0.04 and 0.08, respectively). Our results indicate that transportation for 2 h disturbed the fecal bacterial

  12. INVESTIGATION OF ANTIMICROBIAL ACTIVITY COMBINED PREPARATIONS FOR CLINICAL STRAINS OF MICROORGANISMS ISOLATED FROM PATIENTS WITH BACTERIAL VAGINIT

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    Aslanian M. A.

    2015-12-01

    Full Text Available The problem of bacterial vaginit in some cases the cause of severe infectious diseases genitalia of the fetus and newborn, which can impair the health of future generations. It is noted that the treatment of antibacterial agents observed numerous negative side effects- reducing the biochemical activity of the intestinal microflora, abuse microbiota, leading to the development of dysbiosis, increasing the number of resistant strains of pathogens, the risk of allergic reaction sand immunological disorders. A study was conducted towards finding effective combinations of drugs from different pharmacological groups means to create a combination of drugs. The aim of the study was to develop and explore and Flamini combination of miramistin combined medicines to treat bacterial vaginit. As a result of studies in patients with bacterial vaginit pathological material was isolated and identified 72 strains of microorganisms (Staphylococcus spp, Streptococcus spp, Enterococcus spp, Escherichia coli, Haemophillu sssp, Candida albican sand various strains of anaerobic microorganisms. For the combined treatment of infectious and in flammatory diseases (mixed infections in humans the combined drugin tablet form. All clinical strains of microorganisms isolated from patients with bacterial vaginit were tested for sensitivity to the combined preparation in tablet form with Flamini and miramistin. The greatest sensitivity to the drugs found clinical strains of microorganisms: Staphylococcu saureus, Staphylococcus epidermidis, Peptococcus niger (diameter zone growth retardation is 25,5-23,5 mm. composition tablets number 1 (0.05 g Flamini, miramistini 0.02 g, which was selected for further study shows bacteriostatic effect against a wide range of microorganisms and fungi Rod Candida. IPC for Staphylococcus sp was 20-25 pg / mL for Streptococcus sp 35,0-40,0 mg / ml, for intestinal group 35,0-40,0 for fungi 30,0 mg / ml unlike pills number 2 and number 3, where the

  13. Contrasting activity patterns determined by BrdU incorporation in bacterial ribotypes from the Arctic Ocean in winter

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    Pierre E Galand

    2013-05-01

    Full Text Available The winter Arctic Ocean is one of the most unexplored marine environments from a microbiological perspective. Heterotrophic bacteria maintain their activity at a baseline level during the extremely low energy conditions of the winter, but little is known about the specific phylotypes that have the potential to survive and grow in such harsh environment. In this study, we aimed at identifying actively growing ribotypes in winter Arctic Ocean seawater cultures by experimental incubations with the thymidine analogue bromodeoxyuridine (BrdU, followed by immunocapturing, terminal restriction fragment length polymorphism (TRFLP fingerprinting, cloning and sequencing the 16S rRNA gene. We incubated water collected at different months over the Arctic winter and showed that the actively growing bacterial fraction, taking up BrdU, represented only a subset of the total community. Among the BrdU-labeled bacterial taxa we identified the Flavobacteria Polaribacter, the Alphaproteobacteria SAR11, the Gammaproteobacteria Arctic 96B-16 cluster and, predominately, members of Colwellia spp. Interestingly, Colwellia sequences formed three clusters (93 and 97% pairwise 16S rRNA identity that contributed in contrasting ways to the active communities in the incubations. Polaribacter, Arctic 96B-16 and one cluster of Colwellia were more abundant in the active community represented by the BrdU labelled DNA. In contrast, SAR11 and two other Colwellia clusters were underrepresented in the BrdU labelled community compared to total communities. Despite the limitation of the long incubations needed to label slow growing arctic communities, the BrdU approach revealed the potential for active growth in low-energy conditions in some relevant groups of polar bacteria, including Polaribacter and Arctic 96B-16. Moreover, under similar incubation conditions, the growth of different Colwellia ribotypes varied, suggesting that related clusters of Colwellia may have distinct

  14. Evidence that intramolecular interactions are involved in masking the activation domain of transcriptional activator Leu3p.

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    Wang, D; Hu, Y; Zheng, F; Zhou, K; Kohlhaw, G B

    1997-08-01

    The Leu3 protein of Saccharomyces cerevisiae regulates the expression of genes involved in branched chain amino acid biosynthesis and in ammonia assimilation. It is modulated by alpha-isopropylmalate, an intermediate in leucine biosynthesis. In the presence of alpha-isopropylmalate, Leu3p is a transcriptional activator. In the absence of the signal molecule, the activation domain is masked, and Leu3p acts as a repressor. The recent discovery that Leu3p retains its regulatory properties when expressed in mammalian cells (Guo, H., and Kohlhaw, G. B. (1996) FEBS Lett. 390, 191-195) suggests that masking and unmasking of the activation domain occur without the participation of auxiliary proteins. Here we present experimental support for this notion and address the mechanism of masking. We show that modulation of Leu3p is exceedingly sensitive to mutations in the activation domain. An activation domain double mutant (D872N/D874N; designated Leu3-dd) was constructed that has the characteristics of a permanently masked activator. Using separately expressed segments containing either the DNA binding domain-middle region or the activation domain of wild type Leu3p (or Leu3-dd) in a modified yeast two-hybrid system, we provide direct evidence for alpha-isopropylmalate-dependent interaction between these segments. Finally, we use the phenotype of Leu3-dd-containing cells (slow growth in the absence of added leucine) to select for suppressor mutations that map to the middle region of Leu3-dd. The properties of nine such suppressors further support the idea that masking is an intramolecular process and suggest a means for mapping the surface involved in masking.

  15. Acoustic input and efferent activity regulate the expression of molecules involved in cochlear micromechanics

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    Verónica eLamas

    2015-01-01

    Full Text Available Electromotile activity in auditory outer hair cells (OHCs is essential for sound amplification. It relies on the highly specialized membrane motor protein prestin, and its interactions with the cytoskeleton. It is believed that the expression of prestin and related molecules involved in OHC electromotility may be dynamically regulated by signals from the acoustic environment. However little is known about the nature of such signals and how they affect the expression of molecules involved in electromotility in OHCs. We show evidence that prestin oligomerization is regulated, both at short and relatively long term, by acoustic input and descending efferent activity originating in the cortex, likely acting in concert. Unilateral removal of the middle ear ossicular chain reduces levels of trimeric prestin, particularly in the cochlea from the side of the lesion, whereas monomeric and dimeric forms are maintained or even increased in particular in the contralateral side, as shown in Western blots. Unilater