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Sample records for factors control bacterial

  1. 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.

  2. Bacterial sigma factors as targets for engineered or synthetic transcriptional control.

    Science.gov (United States)

    Tripathi, Lakshmi; Zhang, Yan; Lin, Zhanglin

    2014-01-01

    Sigma (σ) factors are the predominant constituents of transcription regulation in bacteria. σ Factors recruit the core RNA polymerase to recognize promoters with specific DNA sequences. Recently, engineering of transcriptional regulators has become a significant tool for strain engineering. The present review summarizes the recent advances in σ factor based engineering or synthetic design. The manipulation of σ factors presents insights into the bacterial stress tolerance and metabolite productivity. We envision more synthetic design based on σ factors that can be used to tune the regulatory network of bacteria.

  3. Bacterial sigma factors as targets for engineered or synthetic transcriptional control

    Directory of Open Access Journals (Sweden)

    Lakshmi eTripathi

    2014-09-01

    Full Text Available Sigma (σ factors are the predominant constituents of transcription regulation in bacteria. σ factors recruit the core RNA polymerase (RNAP to recognize promoters with specific DNA sequences. Recently engineering of transcriptional regulators has become a significant tool for strain engineering. The present review summarizes the recent advances in σ factor based engineering or synthetic design. The manipulation of σ factors presents insights into the bacterial stress tolerance and metabolite productivity. We envision more synthetic design based on σ factors that can be used to tune the regulatory network of bacteria.

  4. Bacterial colonization factors control specificity and stability of the gut microbiota.

    Science.gov (United States)

    Lee, S Melanie; Donaldson, Gregory P; Mikulski, Zbigniew; Boyajian, Silva; Ley, Klaus; Mazmanian, Sarkis K

    2013-09-19

    Mammals harbour a complex gut microbiome, comprising bacteria that confer immunological, metabolic and neurological benefits. Despite advances in sequence-based microbial profiling and myriad studies defining microbiome composition during health and disease, little is known about the molecular processes used by symbiotic bacteria to stably colonize the gastrointestinal tract. We sought to define how mammals assemble and maintain the Bacteroides, one of the most numerically prominent genera of the human microbiome. Here we find that, whereas the gut normally contains hundreds of bacterial species, germ-free mice mono-associated with a single Bacteroides species are resistant to colonization by the same, but not different, species. To identify bacterial mechanisms for species-specific saturable colonization, we devised an in vivo genetic screen and discovered a unique class of polysaccharide utilization loci that is conserved among intestinal Bacteroides. We named this genetic locus the commensal colonization factors (ccf). Deletion of the ccf genes in the model symbiont, Bacteroides fragilis, results in colonization defects in mice and reduced horizontal transmission. The ccf genes of B. fragilis are upregulated during gut colonization, preferentially at the colonic surface. When we visualize microbial biogeography within the colon, B. fragilis penetrates the colonic mucus and resides deep within crypt channels, whereas ccf mutants are defective in crypt association. Notably, the CCF system is required for B. fragilis colonization following microbiome disruption with Citrobacter rodentium infection or antibiotic treatment, suggesting that the niche within colonic crypts represents a reservoir for bacteria to maintain long-term colonization. These findings reveal that intestinal Bacteroides have evolved species-specific physical interactions with the host that mediate stable and resilient gut colonization, and the CCF system represents a novel molecular mechanism for

  5. EVALUATION OF BIOTIC AND TREATMENT FACTORS RELATING TO BACTERIAL CONTROL OF ZEBRA MUSSELS

    Energy Technology Data Exchange (ETDEWEB)

    Daniel P. Molloy

    2002-04-30

    Testing over the last quarter has indicated the following regarding control of zebra mussels with bacterium Pseudomonas fluorescens strain CL0145A: (1) the concentration of bacteria suspended in water is directly correlated with mussel kill; (2) the ratio of bacterial mass per mussel, if too low, could limit mussel kill; a treatment must be done at a high enough ratio so that mussels do not deplete all the suspended bacteria before the end of the desired exposure period; (3) bacteria appear to lose almost all their toxicity after suspension for 24 hr in highly oxygenated water; (4) in a recirculating pipe system, the same percentage mussel kill will be achieved irrespective of whether all the bacteria are applied at once or divided up and applied intermittently in smaller quantities over a 10-hr period. Since this is the fourth quarterly report, a summation of all test results over the last twelve months is provided as a table in this report. The table includes the above-mentioned fourth-quarter results.

  6. Genetic networks controlled by the bacterial replication initiator and transcription factor DnaA in Bacillus subtilis.

    Science.gov (United States)

    Washington, Tracy A; Smith, Janet L; Grossman, Alan D

    2017-10-01

    DnaA is the widely conserved bacterial AAA+ ATPase that functions as both the replication initiator and a transcription factor. In many organisms, DnaA controls expression of its own gene and likely several others during growth and in response to replication stress. To evaluate the effects of DnaA on gene expression, separate from its role in replication initiation, we analyzed changes in mRNA levels in Bacillus subtilis cells with and without dnaA, using engineered strains in which dnaA is not essential. We found that dnaA was required for many of the changes in gene expression in response to replication stress. We also found that dnaA indirectly affected expression of several regulons during growth, including those controlled by the transcription factors Spo0A, AbrB, PhoP, SinR, RemA, Rok and YvrH. These effects were largely mediated by the effects of DnaA on expression of sda. DnaA activates transcription of sda, and Sda inhibits histidine protein kinases required for activation of the transcription factor Spo0A. We also found that loss of dnaA caused a decrease in the development of genetic competence. Together, our results indicate that DnaA plays an important role in modulating cell physiology, separate from its role in replication initiation. © 2017 John Wiley & Sons Ltd.

  7. Aetiology and factors associated with bacterial diarrhoeal diseases amongst urban refugee children in Eastleigh, Kenya: A case control study

    Directory of Open Access Journals (Sweden)

    Waqo G. Boru

    2013-03-01

    Full Text Available Introduction: Kenya is home to over 400 000 refugees from neighbouring countries. There is scanty information about diarrhoea amongst urban refugees in Kenya.Objectives: We investigated the enteric bacteria causing diarrhoea amongst urban refugee children and described the associated factors.Method: During the period of August–December 2010, urban refugee children between the ages of two and five who attended Eastleigh County Council Health Centre were enrolled into the study. Diarrhoeal cases were compared with age-matched children with no diarrhoea (controls. Stool specimens were collected and enteric bacteria isolated. A questionnaire was administered to identify risk factors.Results: A total of 41 cases and 41 controls were enrolled in the study. The age and country of origin were similar for cases and controls. The bacterial isolation rates amongst the cases were: non-pathogenic Escherichia coli 71%, Shigella dysenteriae 2.4%, Shigella flexneri 2.4%, Salmonella paratyphi 5%. For the controls, non-pathogenic E. coli 90% and enterotoxigenic E. coli (ETEC2.4% were amongst the organisms isolated. All isolates were resistant to amoxicillin; resistance to other antibiotics varied by isolate type. Factors associated independently with diarrhoea included children not washing their hands with soap (aOR 5.9, p < 0.05, neighbour(s having diarrhoea (aOR 39.8, p < 0.05, children not exclusively breastfed for their first 6 months (aOR 7.6, p < 0.05 and children eating food cooked the previous day (aOR 23.8, p = 0.002.Conclusions: Shigella species, Salmonella species and ETEC were found to be responsible for diarrhoea amongst the urban refugee children. Measures to control and guide the use of antibiotics are critical for the prevention of antibiotic resistance. Efforts to improve personal and domestic hygiene, including educational campaigns to promote appropriate handwashing, should be encouraged.

  8. Bacterial Factors Associated with Lethal Outcome of Enteropathogenic Escherichia coli Infection: Genomic Case-Control Studies.

    Directory of Open Access Journals (Sweden)

    Michael S Donnenberg

    2015-05-01

    Full Text Available Typical enteropathogenic Escherichia coli (tEPEC strains were associated with mortality in the Global Enteric Multicenter Study (GEMS. Genetic differences in tEPEC strains could underlie some of the variability in clinical outcome.We produced draft genome sequences of all available tEPEC strains from GEMS lethal infections (LIs and of closely matched EPEC strains from GEMS subjects with non-lethal symptomatic infections (NSIs and asymptomatic infections (AIs to identify gene clusters (potential protein encoding sequences sharing ≥90% nucleotide sequence identity associated with lethality.Among 14,412 gene clusters identified, the presence or absence of 392 was associated with clinical outcome. As expected, more gene clusters were associated with LI versus AI than LI versus NSI. The gene clusters more prevalent in strains from LI than those from NSI and AI included those encoding proteins involved in O-antigen biogenesis, while clusters encoding type 3 secretion effectors EspJ and OspB were among those more prevalent in strains from non-lethal infections. One gene cluster encoding a variant of an NleG ubiquitin ligase was associated with LI versus AI, while two other nleG clusters had the opposite association. Similar associations were found for two nleG gene clusters in an additional, larger sample of NSI and AI GEMS strains.Particular genes are associated with lethal tEPEC infections. Further study of these factors holds potential to unravel the mechanisms underlying severe disease and to prevent adverse outcomes.

  9. A systematic approach for the assessment of bacterial growth-controlling factors linked to biological stability of drinking water in distribution systems

    KAUST Repository

    Prest, E. I.

    2016-01-06

    A systematic approach is presented for the assessment of (i) bacterial growth-controlling factors in drinking water and (ii) the impact of distribution conditions on the extent of bacterial growth in full-scale distribution systems. The approach combines (i) quantification of changes in autochthonous bacterial cell concentrations in full-scale distribution systems with (ii) laboratoryscale batch bacterial growth potential tests of drinking water samples under defined conditions. The growth potential tests were done by direct incubation of water samples, without modification of the original bacterial flora, and with flow cytometric quantification of bacterial growth. This method was shown to be reproducible (ca. 4% relative standard deviation) and sensitive (detection of bacterial growth down to 5 μg L-1 of added assimilable organic carbon). The principle of step-wise assessment of bacterial growth-controlling factors was demonstrated on bottled water, shown to be primarily carbon limited at 133 (±18) × 103 cells mL-1 and secondarily limited by inorganic nutrients at 5,500 (±1,700) × 103 cells mL-1. Analysis of the effluent of a Dutch full-scale drinking water treatment plant showed (1) bacterial growth inhibition as a result of end-point chlorination, (2) organic carbon limitation at 192 (±72) × 103 cells mL-1 and (3) inorganic nutrient limitation at 375 (±31) × 103 cells mL-1. Significantly lower net bacterial growth was measured in the corresponding full-scale distribution system (176 (±25) × 103 cells mL-1) than in the laboratory-scale growth potential test of the same water (294 (±35) × 103 cells mL-1), highlighting the influence of distribution on bacterial growth. The systematic approach described herein provides quantitative information on the effect of drinking water properties and distribution system conditions on biological stability, which can assist water utilities in decision-making on treatment or distribution system improvements to

  10. Factors Controlling Soil Microbial Biomass and Bacterial Diversity and Community Composition in a Cold Desert Ecosystem: Role of Geographic Scale

    OpenAIRE

    Horn, David J. van; Lee Van Horn, M.; Barrett, John E.; Gooseff, Michael N.; Altrichter, Adam E; Geyer, Kevin M; Lydia H Zeglin; Takacs-Vesbach, Cristina D.

    2013-01-01

    Understanding controls over the distribution of soil bacteria is a fundamental step toward describing soil ecosystems, understanding their functional capabilities, and predicting their responses to environmental change. This study investigated the controls on the biomass, species richness, and community structure and composition of soil bacterial communities in the McMurdo Dry Valleys, Antarctica, at local and regional scales. The goals of the study were to describe the relationships between ...

  11. Bacterial control of cyanobacteria

    CSIR Research Space (South Africa)

    Ndlela, Luyanda L

    2017-08-01

    Full Text Available stream_source_info Ndlela_19412_2017.pdf.txt stream_content_type text/plain stream_size 3990 Content-Encoding UTF-8 stream_name Ndlela_19412_2017.pdf.txt Content-Type text/plain; charset=UTF-8 Potential Outcomes... of biological control appears to be direct contact. • Ndlela, L. L. et al. (2016) ‘An overview of cyanobacterial bloom occurrences and research in Africa over the last decade’, Harmful Algae, 60 • Gumbo, J.R. et al. (2010) The Isolation and identification...

  12. Factors Controlling Soil Microbial Biomass and Bacterial Diversity and Community Composition in a Cold Desert Ecosystem: Role of Geographic Scale.

    Directory of Open Access Journals (Sweden)

    David J Van Horn

    Full Text Available Understanding controls over the distribution of soil bacteria is a fundamental step toward describing soil ecosystems, understanding their functional capabilities, and predicting their responses to environmental change. This study investigated the controls on the biomass, species richness, and community structure and composition of soil bacterial communities in the McMurdo Dry Valleys, Antarctica, at local and regional scales. The goals of the study were to describe the relationships between abiotic characteristics and soil bacteria in this unique, microbially dominated environment, and to test the scale dependence of these relationships in a low complexity ecosystem. Samples were collected from dry mineral soils associated with snow patches, which are a significant source of water in this desert environment, at six sites located in the major basins of the Taylor and Wright Valleys. Samples were analyzed for a suite of characteristics including soil moisture, pH, electrical conductivity, soil organic matter, major nutrients and ions, microbial biomass, 16 S rRNA gene richness, and bacterial community structure and composition. Snow patches created local biogeochemical gradients while inter-basin comparisons encompassed landscape scale gradients enabling comparisons of microbial controls at two distinct spatial scales. At the organic carbon rich, mesic, low elevation sites Acidobacteria and Actinobacteria were prevalent, while Firmicutes and Proteobacteria were dominant at the high elevation, low moisture and biomass sites. Microbial parameters were significantly related with soil water content and edaphic characteristics including soil pH, organic matter, and sulfate. However, the magnitude and even the direction of these relationships varied across basins and the application of mixed effects models revealed evidence of significant contextual effects at local and regional scales. The results highlight the importance of the geographic scale of

  13. Mechanism of Excretion of a Bacterial Proteinase: Factors Controlling Accumulation of the Extracellular Proteinase of a Sarcina Strain (Coccus P)

    Energy Technology Data Exchange (ETDEWEB)

    BISSELL, MINA J.; TOSI, ROBERTO; GORINI, LUIGI

    1970-06-29

    also analyze the kinetics of enzyme appearance and accumulation in minimal medium. It is found that Coccus P does not require Ca{sup 2+} for proteinase synthesis or excretion but only in so far as it is essential for enzyme stability. It is further found that the factor responsible for the decline in enzyme accumulation, observed under conditions in which enzyme inactivation or autodigestion is prevented, is the proteolytic activity of the enzyme itself. Thus, in addition to synthesis, excretion, activation, and stability, a novel element plays a role in controlling enzyme accumulation in the culture fluid.

  14. Bacterial Ice Crystal Controlling Proteins

    Directory of Open Access Journals (Sweden)

    Janet S. H. Lorv

    2014-01-01

    Full Text Available Across the world, many ice active bacteria utilize ice crystal controlling proteins for aid in freezing tolerance at subzero temperatures. Ice crystal controlling proteins include both antifreeze and ice nucleation proteins. Antifreeze proteins minimize freezing damage by inhibiting growth of large ice crystals, while ice nucleation proteins induce formation of embryonic ice crystals. Although both protein classes have differing functions, these proteins use the same ice binding mechanisms. Rather than direct binding, it is probable that these protein classes create an ice surface prior to ice crystal surface adsorption. Function is differentiated by molecular size of the protein. This paper reviews the similar and different aspects of bacterial antifreeze and ice nucleation proteins, the role of these proteins in freezing tolerance, prevalence of these proteins in psychrophiles, and current mechanisms of protein-ice interactions.

  15. Comparative analyses imply that the enigmatic sigma factor 54 is a central controller of the bacterial exterior

    Directory of Open Access Journals (Sweden)

    Groot Kormelink Tom

    2011-08-01

    Full Text Available Abstract Background Sigma-54 is a central regulator in many pathogenic bacteria and has been linked to a multitude of cellular processes like nitrogen assimilation and important functional traits such as motility, virulence, and biofilm formation. Until now it has remained obscure whether these phenomena and the control by Sigma-54 share an underlying theme. Results We have uncovered the commonality by performing a range of comparative genome analyses. A The presence of Sigma-54 and its associated activators was determined for all sequenced prokaryotes. We observed a phylum-dependent distribution that is suggestive of an evolutionary relationship between Sigma-54 and lipopolysaccharide and flagellar biosynthesis. B All Sigma-54 activators were identified and annotated. The relation with phosphotransfer-mediated signaling (TCS and PTS and the transport and assimilation of carboxylates and nitrogen containing metabolites was substantiated. C The function annotations, that were represented within the genomic context of all genes encoding Sigma-54, its activators and its promoters, were analyzed for intra-phylum representation and inter-phylum conservation. Promoters were localized using a straightforward scoring strategy that was formulated to identify similar motifs. We found clear highly-represented and conserved genetic associations with genes that concern the transport and biosynthesis of the metabolic intermediates of exopolysaccharides, flagella, lipids, lipopolysaccharides, lipoproteins and peptidoglycan. Conclusion Our analyses directly implicate Sigma-54 as a central player in the control over the processes that involve the physical interaction of an organism with its environment like in the colonization of a host (virulence or the formation of biofilm.

  16. Bacterial vaginosis among women with tubal factor infertility in Nigeria.

    Science.gov (United States)

    Durugbo, Innocent I; Nyengidiki, Tamunomie K; Bassey, Goddy; Wariso, Kennedy T

    2015-11-01

    To determine the prevalence of bacterial vaginosis among women with tubal factor infertility. A cross-sectional prospective study of women with tubal factor infertility was conducted at a Nigerian teaching hospital between March and September 2014. An equal number of fertile women attending the family planning clinic were recruited as controls. Interviews were conducted to collect data on sociodemographic characteristics, history and characteristics of vaginal discharge, knowledge, and practices. Bacterial vaginosis was diagnosed using the Amsel criteria. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to determine predisposing factors. Overall, 178 women with tubal factor infertility were recruited. Bacterial vaginosis was noted in 50 (28.1%) of these women, compared with 14 (7.9%) of 178 fertile women (P vaginosis when they were of low socioeconomic class (OR 11.89; 95% CI 5.20-27.69), practiced vaginal douching (OR 19.15; 95% CI 7.26-47.75), used vaginal drying agents (OR 17.04; 95% CI 6.91-43.24), had an early sexual debut (OR 32.08; 95% CI 12.02-88.89), and had a history of sexually transmitted infections (OR 12.42; 95% CI 5.36-29.35). The prevalence of bacterial vaginosis was high among patients with tubal factor infertility. Socioeconomic and cultural factors contribute to the risk of the condition. Copyright © 2015 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

  17. Factors limiting heterotrophic bacterial production in the southern Pacific Ocean

    Directory of Open Access Journals (Sweden)

    F. Van Wambeke

    2007-10-01

    Full Text Available The role of potential factors limiting bacterial growth was investigated along vertical and longitudinal gradients across the South Eastern Pacific Gyre. The effects of glucose, nitrate, ammonium and phosphate additions on heterotrophic bacterial production (using leucine technique were studied in parallel in unfiltered seawater samples incubated under natural daily irradiance. Longitudinally, the enrichments realized on the subsurface showed three types of responses. From the Marquesas plateau (8° W to approx 125° W, bacteria were not bottom-up controlled, as confirmed by the huge potential of growth in non-enriched seawater (43±24 times in 24 h. Within the Gyre (125° W–95° W, nitrogen alone stimulated leucine incorporation rates by a factor of 5.6±3.6, but rapidly labile carbon (glucose became a second limiting factor (enhancement factor 49±32 when the two elements were added. Finally from the border of the gyre to the Chilean upwelling (95° W–73° W, labile carbon was the only factor stimulating heterotrophic bacterial production. Interaction between phytoplankton and heterotrophic bacterial communities and the direct versus indirect effect of iron and macronutrients on bacterial production were also investigated in four selected sites: two sites on the vicinity of the Marquesas plateau, the centre of the gyre and the Eastern border of the gyre. Both phytoplankton and heterotrophic bacteria were limited by availability of nitrogen within the gyre, but not by iron. While iron limited phytoplankton at Marquesas plateau and at the eastern border of the gyre, heterotrophic bacteria were only limited by availability of labile DOC in those environments.

  18. Bacterial Sigma Factors and Anti-Sigma Factors: Structure, Function and Distribution

    OpenAIRE

    Paget, Mark S.

    2015-01-01

    Sigma factors are multi-domain subunits of bacterial RNA polymerase (RNAP) that play critical roles in transcription initiation, including the recognition and opening of promoters as well as the initial steps in RNA synthesis. This review focuses on the structure and function of the major sigma-70 class that includes the housekeeping sigma factor (Group 1) that directs the bulk of transcription during active growth, and structurally-related alternative sigma factors (Groups 2–4) that control ...

  19. Modus operandi of the bacterial RNA polymerase containing the sigma54 promoter-specificity factor.

    Science.gov (United States)

    Wigneshweraraj, Sivaramesh; Bose, Daniel; Burrows, Patricia C; Joly, Nicolas; Schumacher, Jörg; Rappas, Mathieu; Pape, Tillmann; Zhang, Xiaodong; Stockley, Peter; Severinov, Konstantin; Buck, Martin

    2008-05-01

    Bacterial sigma (sigma) factors confer gene specificity upon the RNA polymerase, the central enzyme that catalyses gene transcription. The binding of the alternative sigma factor sigma(54) confers upon the RNA polymerase special functional and regulatory properties, making it suited for control of several major adaptive responses. Here, we summarize our current understanding of the interactions the sigma(54) factor makes with the bacterial transcription machinery.

  20. Bacterial Sigma Factors and Anti-Sigma Factors: Structure, Function and Distribution.

    Science.gov (United States)

    Paget, Mark S

    2015-06-26

    Sigma factors are multi-domain subunits of bacterial RNA polymerase (RNAP) that play critical roles in transcription initiation, including the recognition and opening of promoters as well as the initial steps in RNA synthesis. This review focuses on the structure and function of the major sigma-70 class that includes the housekeeping sigma factor (Group 1) that directs the bulk of transcription during active growth, and structurally-related alternative sigma factors (Groups 2-4) that control a wide variety of adaptive responses such as morphological development and the management of stress. A recurring theme in sigma factor control is their sequestration by anti-sigma factors that occlude their RNAP-binding determinants. Sigma factors are then released through a wide variety of mechanisms, often involving branched signal transduction pathways that allow the integration of distinct signals. Three major strategies for sigma release are discussed: regulated proteolysis, partner-switching, and direct sensing by the anti-sigma factor.

  1. Hard-Wired Control of Bacterial Processes by Chromosomal Gene Location

    NARCIS (Netherlands)

    Slager, Jelle; Veening, Jan-Willem

    2016-01-01

    Bacterial processes, such as stress responses and cell differentiation, are controlled at many different levels. While some factors, such as transcriptional regulation, are well appreciated, the importance of chromosomal gene location is often underestimated or even completely neglected. A

  2. Hard-Wired Control of Bacterial Processes by Chromosomal Gene Location

    NARCIS (Netherlands)

    Slager, Jelle; Veening, Jan-Willem

    2016-01-01

    Bacterial processes, such as stress responses and cell differentiation, are controlled at many different levels. While some factors, such as transcriptional regulation, are well appreciated, the importance of chromosomal gene location is often underestimated or even completely neglected. A combinati

  3. Risk factors for bacterial vaginosis in pregnancy: a population-based study on Danish women

    DEFF Research Database (Denmark)

    Thorsen, Poul; Vogel, Ida; Molsted, Kirsten

    2006-01-01

    Background. No larger population-based study of bacterial vaginosis in pregnancy has previously been available. The objective of this study was to examine risk factors for bacterial vaginosis in pregnancy. Design. From a prospective population-based cohort of 3,596 eligible pregnant women, 2......, and sociodemographic factors) were computed. Results. At enrolment, bacterial vaginosis was diagnosed in 13.7% of Danish pregnant women. Significant risk factors for bacterial vaginosis were: daily coitus (adjusted relative risk 2.09 [1.43-3.04]), being single (1.76 [1.21-2.56]), smoking more than 10 cigarettes daily...... at conception (1.59 [1.29-1.93]), previous genital infection with Chlamydia trachomatis or Neisseria gonorrhoeae (1.39 [1.07-1.79]), and consuming 2 or more drinks per week (1.33 [1.02-1.74]) after control for confounding factors. Conclusion. In pregnancy, women who have daily coitus, are single, smokers...

  4. Use of Bacteriophages to control bacterial pathogens

    Science.gov (United States)

    Lytic bacteriophages can provide a natural method and an effective alternative to antibiotics to reduce bacterial pathogens in animals, foods, and other environments. Bacteriophages (phages) are viruses which infect bacterial cells and eventually kill them through lysis, and represent the most abun...

  5. Bacterial toxins: an overview on bacterial proteases and their action as virulence factors.

    Science.gov (United States)

    Lebrun, I; Marques-Porto, R; Pereira, A S; Pereira, A; Perpetuo, E A

    2009-06-01

    Bacterial pathogenicity is a result of a combination of factors, including resistance to environmental threats and to the host's defenses, growth capability, localization in the host, tissue specificity, resource obtaining mechanisms and the bacterium's own defenses to aggression. A variety of bacterial components, often specific to each strain, are involved in the microorganism's survival, adhesion and growth in the host. Many of them are harmful and, therefore, are called virulence factors. The effects caused by the virulence factors determine the degree of aggressivity of the strain. In many cases the virulence factors are secreted proteins or enzymes, sometimes performing very specific functions. The enzymatic activity is directed to specific proteins from cell membranes, synaptic vesicle fusion proteins, among other important targets. One of the most toxic bacterial proteins is secreted by Clostridium botulinum, targeted to synaptic vesicle fusion proteins, cleaving them with a zinc-metalloprotease activity, which results in severe neurotoxic effects with a lethal dose as low as eight nanograms per kilogram of body weight. The tetanus neurotoxin acts in a similar way but is less active and Bacillus anthracis also presents a potent metalloprotease activity. In this work we describe a selection of these specially interesting and important bacterial proteins and proteases, stressing their relevance in the pathological process and in medical studies.

  6. Correlation of bacterial vaginosis with preterm labour: a case control study

    OpenAIRE

    Waseeqa Nigeen; Abdus Sami Bhat; Khushboo Gulzar; Shehnaz Taing

    2015-01-01

    Background: Bacterial vaginosis (BV) is thought to be an important risk factor and predictor of preterm labour. Prevention and early detection and treatment of BV can decrease the incidence of preterm labour. Primary objective of this study was to find out correlation of bacterial vaginosis with preterm labour. Secondary objectives were determination of most important criterion among the Amsels criteria and risk factors for BV among literacy, residence and parity. Methods: A Case-control s...

  7. Factors that influence the speed of bacterial wood degradation

    NARCIS (Netherlands)

    Klaassen, R.K.W.M.; Overeem, van B.S.

    2012-01-01

    Bacterial wood decay is a serious threat to the many wooden foundation piles in the Netherlands. In order to learn more about the factors that influence the process of decay, approx. 2000 wood samples taken from Amsterdam piles heads were analysed on type and degree of decay and for 59 extracted pil

  8. Bacterial Sigma Factors and Anti-Sigma Factors: Structure, Function and Distribution

    Directory of Open Access Journals (Sweden)

    Mark S. Paget

    2015-06-01

    Full Text Available Sigma factors are multi-domain subunits of bacterial RNA polymerase (RNAP that play critical roles in transcription initiation, including the recognition and opening of promoters as well as the initial steps in RNA synthesis. This review focuses on the structure and function of the major sigma-70 class that includes the housekeeping sigma factor (Group 1 that directs the bulk of transcription during active growth, and structurally-related alternative sigma factors (Groups 2–4 that control a wide variety of adaptive responses such as morphological development and the management of stress. A recurring theme in sigma factor control is their sequestration by anti-sigma factors that occlude their RNAP-binding determinants. Sigma factors are then released through a wide variety of mechanisms, often involving branched signal transduction pathways that allow the integration of distinct signals. Three major strategies for sigma release are discussed: regulated proteolysis, partner-switching, and direct sensing by the anti-sigma factor.

  9. Climate factors influencing bacterial count in background air samples.

    Science.gov (United States)

    Harrison, Roy M; Jones, Alan M; Biggins, Peter D E; Pomeroy, Nigel; Cox, Christopher S; Kidd, Stephen P; Hobman, Jon L; Brown, Nigel L; Beswick, Alan

    2005-01-01

    Total (as opposed to culturable) bacterial number counts are reported for four sites in the United Kingdom measured during campaigns over four separate seasons. These are interpreted in relation to simple climatic factors, i.e. temperature, wind speed and wind direction. Temperature has a marked effect at all four sites with data for a rural coastal site conforming best to a simple exponential model. Data for the other rural and urban locations show a baseline similar to that determined at the coastal rural location, but with some very significant positive excursions. The temperature dependence of bacterial number is found to conform to that typical of bacterial growth rates. At the coastal rural location, bacterial numbers normalised for temperature show no dependence on wind speed whilst at the inland sites there is a decrease with increasing wind speed of the form expected for a large area source. Only one site appeared to show a systematic relationship of bacterial concentrations to wind direction that being a site in the suburbs of Birmingham with highest number concentrations observed on a wind sector approaching from the city centre. PCR techniques have been used to identify predominant types of bacteria and results are presented which show that Bacillus was the dominant genus observed at the three inland sites during the winter and summer seasons. Pseudomonas appeared with comparable frequency at certain sites and seasons. There was in general a greater diversity of bacteria at the coastal site than at the inland sites.

  10. Risk factors for community-acquired bacterial meningitis

    DEFF Research Database (Denmark)

    Lundbo, Lene Fogt; Benfield, Thomas

    2017-01-01

    of these are pathogen-specific, while some are shared between different bacteria. METHODS: We searched the database PubMed to identify host risk factors for bacterial meningitis caused by the pathogens Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae type b, because they are three most common....... CONCLUSIONS: As conjugated vaccines are available for these infections, it is of utmost importance to identify high risk patients to be able to prevent invasive disease....... causative bacteria beyond the neonatal period. RESULTS: We describe a number of risk factors; including socioeconomic factors, age, genetic variation of the host and underlying medical conditions associated with increased susceptibility to invasive bacterial infections in both children and adults...

  11. Case-control Study of Risk Factors of Central Venous Catheter Tip Bacterial Colonization%中心静脉导管尖端细菌定植危险因素的病例对照研究

    Institute of Scientific and Technical Information of China (English)

    闫沛; 李武平; 宋向阳; 孙惠英; 刘冰

    2011-01-01

    目的 探讨中心静脉导管尖端细菌定植的危险因素.方法 抽取一段时间内某院住院并接受中心静脉置管的患者240例,以导管尖端细菌培养阳性者作为病例组,阴性者作为对照组.对可能影响细菌定植的因素作单因素分析与Logistic多元回归分析.结果 排除可疑污染的阳性病例5例,30例导管尖端有细菌定植,单因素分析共筛选出插入导管型号、拔管前是否有发热、拔管时穿刺点皮肤、导管使用过程中抗生素的使用情况、从导管有无输血、从肝素帽推药次数6方面因素有统计学意义(P<0.05);以有细菌定植为应变量,其他因素为自变量赋值后进行非条件多因素分析,最终显示导管型号、抗生素的使用2方面因素是导管尖端细菌定植的危险因素.结论 选择合适的导管,做好穿刺点护理,严格控制置管天数,合理使用抗生素,有效预防导管相关性血流感染的发生.%Objective To explore risk factors of central venous catheter tip bacterial colonization. Methods 240 inpatients with central venous catheter were divided into case group including positive carriers of bacteria colonization and control group including negative carriers. The potential influence factors were analyzed by single factor analysis and Logistic regression analysis. Results After the exclusion of 5 possibly-polluted cases, 30 cases were with bacterial colonization in the study. Single factor analysis revealed that bacteria colonization were related with 6 factors(P<0.05), which involved catheter size, whether there was a fever before pulling the catheter, the skin of catheter insert spot, antibiotic usage during the process of catheter use, whether there was a blood transfusion from catheter and the frequency of push drugs from heparin joint Non-conditional multiple Logistic regression taking bacteria colonization as dependent variable and the other factors as independent variable indicated that risk

  12. Optimal control methods for controlling bacterial populations with persister dynamics

    Science.gov (United States)

    Cogan, N. G.

    2016-06-01

    Bacterial tolerance to antibiotics is a well-known phenomena; however, only recent studies of bacterial biofilms have shown how multifaceted tolerance really is. By joining into a structured community and offering shared protection and gene transfer, bacterial populations can protect themselves genotypically, phenotypically and physically. In this study, we collect a line of research that focuses on phenotypic (or plastic) tolerance. The dynamics of persister formation are becoming better understood, even though there are major questions that remain. The thrust of our results indicate that even without detailed description of the biological mechanisms, theoretical studies can offer strategies that can eradicate bacterial populations with existing drugs.

  13. Control of intestinal bacterial proliferation in regulation of lifespan in Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Portal-Celhay Cynthia

    2012-03-01

    Full Text Available Abstract Background A powerful approach to understanding complex processes such as aging is to use model organisms amenable to genetic manipulation, and to seek relevant phenotypes to measure. Caenorhabditis elegans is particularly suited to studies of aging, since numerous single-gene mutations have been identified that affect its lifespan; it possesses an innate immune system employing evolutionarily conserved signaling pathways affecting longevity. As worms age, bacteria accumulate in the intestinal tract. However, quantitative relationships between worm genotype, lifespan, and intestinal lumen bacterial load have not been examined. We hypothesized that gut immunity is less efficient in older animals, leading to enhanced bacterial accumulation, reducing longevity. To address this question, we evaluated the ability of worms to control bacterial accumulation as a functional marker of intestinal immunity. Results We show that as adult worms age, several C. elegans genotypes show diminished capacity to control intestinal bacterial accumulation. We provide evidence that intestinal bacterial load, regulated by gut immunity, is an important causative factor of lifespan determination; the effects are specified by bacterial strain, worm genotype, and biologic age, all acting in concert. Conclusions In total, these studies focus attention on the worm intestine as a locus that influences longevity in the presence of an accumulating bacterial population. Further studies defining the interplay between bacterial species and host immunity in C. elegans may provide insights into the general mechanisms of aging and age-related diseases.

  14. Bacterial biofilm formation, pathogenicity, diagnostics and control: An overview

    Directory of Open Access Journals (Sweden)

    Sawhney Rajesh

    2009-07-01

    Full Text Available Bacterial biofilms are complex, mono- or poly-microbialn communities adhering to biotic or abiotic surfaces. This adaptation has been implicated as a survival strategy. The formation of biofilms is mediated by mechanical, biochemical and genetical factors. The biofilms enhance the virulence of the pathogen and have their potential role in various infections, such as dental caries, cystic fibrosis, osteonecrosis, urinary tract infection and eye infections. A number of diagnostic techniques, viz., bright-field microscopy, epifluorescence microscopy, scanning electron microscopy, confocal laser scanning microscopy and amplicon length heterogeneity polymerase chain reaction, have been employed for detection of these communities. Researchers have worked on applications of catheter lock solutions, a fish protein coating, acid shock treatment, susceptibility to bacteriophages, etc., for biofilm control. However, we need to rearrange our strategies to have thorough insight and concentrate on priority basis to develop new accurate, precise and rapid diagnostic protocols for detection and evaluation of biofilm. Above all, the strict compliance to these techniques is required for accurate diagnosis and control.

  15. Novel Conserved Assembly Factor of the Bacterial Flagellum▿

    Science.gov (United States)

    Titz, Björn; Rajagopala, Seesandra V.; Ester, Claudia; Häuser, Roman; Uetz, Peter

    2006-01-01

    TP0658 (FliW) and its orthologs, conserved proteins of unknown function in Treponema pallidum and other species, interact with a C-terminal region of flagellin (FlaB1-3 in T. pallidum; FliC in most other species). Mutants of orthologs in Bacillus subtilis and Campylobacter jejuni (yviF, CJ1075) showed strongly reduced motility. TP0658 stabilizes flagellin in a way similar to FliS, suggesting that TP0658 is a conserved assembly factor for the bacterial flagellum. PMID:16936039

  16. Novel conserved assembly factor of the bacterial flagellum.

    Science.gov (United States)

    Titz, Björn; Rajagopala, Seesandra V; Ester, Claudia; Häuser, Roman; Uetz, Peter

    2006-11-01

    TP0658 (FliW) and its orthologs, conserved proteins of unknown function in Treponema pallidum and other species, interact with a C-terminal region of flagellin (FlaB1-3 in T. pallidum; FliC in most other species). Mutants of orthologs in Bacillus subtilis and Campylobacter jejuni (yviF, CJ1075) showed strongly reduced motility. TP0658 stabilizes flagellin in a way similar to FliS, suggesting that TP0658 is a conserved assembly factor for the bacterial flagellum.

  17. Genome engineering and gene expression control for bacterial strain development.

    Science.gov (United States)

    Song, Chan Woo; Lee, Joungmin; Lee, Sang Yup

    2015-01-01

    In recent years, a number of techniques and tools have been developed for genome engineering and gene expression control to achieve desired phenotypes of various bacteria. Here we review and discuss the recent advances in bacterial genome manipulation and gene expression control techniques, and their actual uses with accompanying examples. Genome engineering has been commonly performed based on homologous recombination. During such genome manipulation, the counterselection systems employing SacB or nucleases have mainly been used for the efficient selection of desired engineered strains. The recombineering technology enables simple and more rapid manipulation of the bacterial genome. The group II intron-mediated genome engineering technology is another option for some bacteria that are difficult to be engineered by homologous recombination. Due to the increasing demands on high-throughput screening of bacterial strains having the desired phenotypes, several multiplex genome engineering techniques have recently been developed and validated in some bacteria. Another approach to achieve desired bacterial phenotypes is the repression of target gene expression without the modification of genome sequences. This can be performed by expressing antisense RNA, small regulatory RNA, or CRISPR RNA to repress target gene expression at the transcriptional or translational level. All of these techniques allow efficient and rapid development and screening of bacterial strains having desired phenotypes, and more advanced techniques are expected to be seen.

  18. Control of bacterial iron homeostasis by manganese

    Science.gov (United States)

    Puri, Sumant; Hohle, Thomas H.; O'Brian, Mark R.

    2010-01-01

    Perception and response to nutritional iron availability by bacteria are essential to control cellular iron homeostasis. The Irr protein from Bradyrhizobium japonicum senses iron through the status of heme biosynthesis to globally regulate iron-dependent gene expression. Heme binds directly to Irr to trigger its degradation. Here, we show that severe manganese limitation created by growth of a Mn2+ transport mutant in manganese-limited media resulted in a cellular iron deficiency. In wild-type cells, Irr levels were attenuated under manganese limitation, resulting in reduced promoter occupancy of target genes and altered iron-dependent gene expression. Irr levels were high regardless of manganese availability in a heme-deficient mutant, indicating that manganese normally affects heme-dependent degradation of Irr. Manganese altered the secondary structure of Irr in vitro and inhibited binding of heme to the protein. We propose that manganese limitation destabilizes Irr under low-iron conditions by lowering the threshold of heme that can trigger Irr degradation. The findings implicate a mechanism for the control of iron homeostasis by manganese in a bacterium. PMID:20498065

  19. Silicon control of bacterial and viral diseases in plants

    Directory of Open Access Journals (Sweden)

    Sakr Nachaat

    2016-12-01

    Full Text Available Silicon plays an important role in providing tolerance to various abiotic stresses and augmenting plant resistance against diseases. However, there is a paucity of reports about the effect of silicon on bacterial and viral pathogens of plants. In general, the effect of silicon on plant resistance against bacterial diseases is considered to be due to either physical defense or increased biochemical defense. In this study, the interaction between silicon foliar or soil-treatments and reduced bacterial and viral severity was reviewed. The current review explains the agricultural importance of silicon in plants, refers to the control of bacterial pathogens in different crop plants by silicon application, and underlines the different mechanisms of silicon-enhanced resistance. A section about the effect of silicon in decreasing viral disease intensity was highlighted. By combining the data presented in this study, a better comprehension of the complex interaction between silicon foliar- or soil-applications and bacterial and viral plant diseases could be achieved.

  20. Factors affecting daughter cells' arrangement during the early bacterial divisions.

    Directory of Open Access Journals (Sweden)

    Pin-Tzu Su

    Full Text Available On agar plates, daughter cells of Escherichia coli mutually slide and align side-by-side in parallel during the first round of binary fission. This phenomenon has been previously attributed to an elastic material that restricts apparently separated bacteria from being in string. We hypothesize that the interaction between bacteria and the underneath substratum may affect the arrangement of the daughter bacteria. To test this hypothesis, bacterial division on hyaluronic acid (HA gel, as an alternative substratum, was examined. Consistent with our proposition, the HA gel differs from agar by suppressing the typical side-by-side alignments to a rare population. Examination of bacterial surface molecules that may contribute to the daughter cells' arrangement yielded an observation that, with disrupted lpp, the E. coli daughter cells increasingly formed non-typical patterns, i.e. neither sliding side-by-side in parallel nor forming elongated strings. Therefore, our results suggest strongly that the early cell patterning is affected by multiple interaction factors. With oscillatory optical tweezers, we further demonstrated that the interaction force decreased in bacteria without Lpp, a result substantiating our notion that the side-by-side sliding phenomenon directly reflects the strength of in-situ interaction between bacteria and substratum.

  1. Local and regional factors influencing bacterial community assembly.

    Science.gov (United States)

    Lindström, Eva S; Langenheder, Silke

    2012-02-01

    The classical view states that microbial biogeography is not affected by dispersal barriers or historical events, but only influenced by the local contemporary habitat conditions (species sorting). This has been challenged during recent years by studies suggesting that also regional factors such as mass effect, dispersal limitation and neutral assembly are important for the composition of local bacterial communities. Here we summarize results from biogeography studies in different environments, i.e. in marine, freshwater and soil as well in human hosts. Species sorting appears to be the most important mechanism. However, this result might be biased since this is the mechanism that is easiest to measure, detect and interpret. Hence, the importance of regional factors may have been underestimated. Moreover, our survey indicates that different assembly mechanisms might be important for different parts of the total community, differing, for example, between generalists and specialists, and between taxa of different dispersal ability and motility. We conclude that there is a clear need for experimental studies, first, to clearly separate regional and local factors in order to study their relative importance, and second, to test whether there are differences in assembly mechanisms depending on different taxonomic or functional groups.

  2. Severe bacterial infections in patients with non-transfusion-dependent thalassemia: prevalence and clinical risk factors

    Directory of Open Access Journals (Sweden)

    Nattiya Teawtrakul

    2015-10-01

    Conclusion: The prevalence of bacterial infection in patients with NTDT was found to be moderate. Time after splenectomy >10 years, deferoxamine therapy, and iron overload may be clinical risk factors for severe bacterial infection in patients with NTDT. Bacterial infection should be recognized in splenectomized patients with NTDT, particularly those who have an iron overload.

  3. Prognostic indicators in bacterial meningitis: a case-control study

    Directory of Open Access Journals (Sweden)

    Maria de Fátima Magalhães Acioly Mendizabal

    Full Text Available This was a case-control study to identify prognostic indicators of bacterial meningitis in a reference hospital in Pernambuco/Brazil. The data were collected from charts of 294 patients with bacterial meningitis between January 2000 and December 2004. Variables were grouped in biological, clinical, laboratory and etiologic agent/treatment. Variables selected in each step were grouped and adjusted for age. Two models were created: one containing clinical variables (clinical model and other containing laboratory variables (laboratory model. In the clinical model the variables associated with death due to bacterial meningitis were dyspnea (p = 0.006, evidence of shock (p = 0.051, evidence of altered mental state (p = 0.000, absence of headache (p = 0.008, absence of vomiting (p = 0.052, and age >40 years old (p = 0.013. In the laboratory model, the variables associated with death due to bacterial meningitis were positive blood cultures (p = 0.073 and thrombocytopenia (p = 0.019. Identification of prognostic indicators soon after admission may allow early specific measures, like admission of patients with higher risk of death to Intensive Care Units.

  4. A model for sigma factor competition in bacterial cells.

    Science.gov (United States)

    Mauri, Marco; Klumpp, Stefan

    2014-10-01

    Sigma factors control global switches of the genetic expression program in bacteria. Different sigma factors compete for binding to a limited pool of RNA polymerase (RNAP) core enzymes, providing a mechanism for cross-talk between genes or gene classes via the sharing of expression machinery. To analyze the contribution of sigma factor competition to global changes in gene expression, we develop a theoretical model that describes binding between sigma factors and core RNAP, transcription, non-specific binding to DNA and the modulation of the availability of the molecular components. The model is validated by comparison with in vitro competition experiments, with which excellent agreement is found. Transcription is affected via the modulation of the concentrations of the different types of holoenzymes, so saturated promoters are only weakly affected by sigma factor competition. However, in case of overlapping promoters or promoters recognized by two types of sigma factors, we find that even saturated promoters are strongly affected. Active transcription effectively lowers the affinity between the sigma factor driving it and the core RNAP, resulting in complex cross-talk effects. Sigma factor competition is not strongly affected by non-specific binding of core RNAPs, sigma factors and holoenzymes to DNA. Finally, we analyze the role of increased core RNAP availability upon the shut-down of ribosomal RNA transcription during the stringent response. We find that passive up-regulation of alternative sigma-dependent transcription is not only possible, but also displays hypersensitivity based on the sigma factor competition. Our theoretical analysis thus provides support for a significant role of passive control during that global switch of the gene expression program.

  5. Emerging frontiers in detection and control of bacterial biofilms.

    Science.gov (United States)

    Tan, Seth Yang-En; Chew, Su Chuen; Tan, Sean Yang-Yi; Givskov, Michael; Yang, Liang

    2014-04-01

    Bacteria form surface-attached biofilm communities in nature. In contrast to free-living cells, bacterial cells within biofilms resist sanitizers and antimicrobials. While building biofilms, cells physiologically adapt to sustain the otherwise lethal impacts of a variety of environmental stress conditions. In this development, the production and embedding of cells in extracellular polymeric substances plays a key role. Biofilm bacteria can cause a range of problems to food processing including reduced heat-cold transfer, clogging water pipelines, food spoilage and they may cause infections among consumers. Recent biofilm investigations with the aim of potential control approaches include a combination of bacterial genetics, systems biology, materials and mechanic engineering and chemical biology.

  6. Bovine milk osteopontin - Targeting bacterial adhesion for biofilm control

    DEFF Research Database (Denmark)

    Kristensen, Mathilde Frost; Meyer, Rikke Louise; Schlafer, Sebastian

    Self-performed mechanical tooth cleaning does usually not result in complete biofilm removal, due to the complex oral anatomy and the strong adhesion of the biofilm to the tooth. Therefore, different supportive measures are employed, most of which aim at the chemical eradication of bacteria...... in dental biofilms. As their bactericidal action impacts the entire oral microflora, agents that inhibit biofilm formation without killing bacteria, such as the bovine milk protein osteopontin, have gained increasing attention. Here, we investigate the adhesion of 8 bacterial species associated with dental.......05). ), as determined by two-sample t-tests. The broad range anti-adhesive effect of osteopontin on dental bacterial strains might explain the reduced biofilm formation observed and be exploited in vivo for increased caries control....

  7. Factors Affecting Bacterial Growth in Drinking Water Distribution System

    Institute of Scientific and Technical Information of China (English)

    WEI LU; XIAO-JIAN ZHANG

    2005-01-01

    Objective To define the influence of some parameters, including assimilable organic carbon (AOC), chloramine residual, etc. on the bacterial growth in drinking water distribution systems. Methods Three typical water treatment plants in a northern city (City T) of China and their corresponding distribution systems were investigated. Some parameters of the water samples, such as heterotrophic plate content (HPC), AOC, CODMn, TOC, and phosphate were measured. Results The AOC in most water samples were more than 100 μg/L, or even more than 200 μg/L in some cases. The HPC in distribution systems increased significantly with the decrease of residual chlorine. When the residual chlorine was less than 0.1 mg/L, the magnitude order of HPC was 104 CFU/mL; when it was 0.5-0.7 mg/L, the HPC was about 500 CFU/mL. Conclusion For controlling the biostability of drinking water, the controlling of AOC and residual chlorine should be considered simultaneously. The influence of phosphors on the AOC tests of water is not significant. Phosphors may not be the limiting nutrient in the water distribution systems.

  8. Risk factors for community-acquired bacterial meningitis in adults

    NARCIS (Netherlands)

    Adriani, K.S.

    2015-01-01

    Bacterial meningitis is an inflammation of the meninges and occurs when bacteria invade the subarachnoid space. The meninges are the protective membranes that surround the brain and the spinal cord. Bacterial meningitis is a life-threatening disease because the proximity of the infection to the brai

  9. Control of bacterial exoelectrogenesis by c-AMP-GMP.

    Science.gov (United States)

    Nelson, James W; Sudarsan, Narasimhan; Phillips, Grace E; Stav, Shira; Lünse, Christina E; McCown, Phillip J; Breaker, Ronald R

    2015-04-28

    Major changes in bacterial physiology including biofilm and spore formation involve signaling by the cyclic dinucleotides c-di-GMP and c-di-AMP. Recently, another second messenger dinucleotide, c-AMP-GMP, was found to control chemotaxis and colonization by Vibrio cholerae. We have identified a superregulon of genes controlled by c-AMP-GMP in numerous Deltaproteobacteria, including Geobacter species that use extracellular insoluble metal oxides as terminal electron acceptors. This exoelectrogenic process has been studied for its possible utility in energy production and bioremediation. Many genes involved in adhesion, pilin formation, and others that are important for exoelectrogenesis are controlled by members of a variant riboswitch class that selectively bind c-AMP-GMP. These RNAs constitute, to our knowledge, the first known specific receptors for c-AMP-GMP and reveal that this molecule is used by many bacteria to control specialized physiological processes.

  10. Combinatorial approach for fabrication of coatings to control bacterial adhesion.

    Science.gov (United States)

    Pedron, S; Peinado, C; Catalina, F; Bosch, P; Anseth, K S; Abrusci, C

    2012-01-01

    Due to the high importance of bacterial infections in medical devices there is an increasing interest in the design of anti-fouling coatings. The application of substrates with controlled chemical gradients to prevent microbial adhesion is presented. We describe here the co-polymerization of poly(ethylene glycol) dimethacrylate with a hyperbranched multimethacrylate (H30MA) using a chemical gradient generator; and the resulting films were characterized with respect to their ability to serve as coating for biomedical devices. The photo-polymerized materials present special surface properties due to the hyperbranched structure of H30MA and phase separation at specific concentrations in the PEGDM matrix. This approach affords the investigation of cell response to a large range of different chemistries on a single sample. Two bacterial strains commonly associated with surgical site infections, Escherichia coli and Pseudomonas aeruginosa, have been cultured on these substrates to study their attachment behaviour. These gradient-coated samples demonstrate less bacterial adhesion at higher concentrations of H30MA, and the adhesion is substantially affected by the extent of surface phase segregation.

  11. Factors associated with asthma control.

    NARCIS (Netherlands)

    Vries, M.P. de; Bemt, E.A.J.M. van den; Lince, S.; Muris, J.W.M.; Thoonen, B.P.A.; Schayck, C.P. van

    2005-01-01

    The aim of this study was to evaluate which factors are associated with asthma control experienced by asthma patients. In a cross-sectional study patients aged 16-60 years with mild to moderate asthma were selected. The influence of the following factors on asthma control was studied in a multivaria

  12. Potential mechanisms and environmental controls of TiO2 nanoparticle effects on soil bacterial communities.

    Science.gov (United States)

    Ge, Yuan; Priester, John H; Van De Werfhorst, Laurie C; Schimel, Joshua P; Holden, Patricia A

    2013-12-17

    It has been reported that engineered nanoparticles (ENPs) alter soil bacterial communities, but the underlying mechanisms and environmental controls of such effects remain unknown. Besides direct toxicity, ENPs may indirectly affect soil bacteria by changing soil water availability or other properties. Alternatively, soil water or other environmental factors may mediate ENP effects on soil bacterial communities. To test, we incubated nano-TiO2-amended soils across a range of water potentials for 288 days. Following incubation, the soil water characteristics, organic matter, total carbon, total nitrogen, and respiration upon rewetting (an indicator of bioavailable organic carbon) were measured. Bacterial community shifts were characterized by terminal restriction fragment length polymorphism (T-RFLP). The endpoint soil water holding had been reported previously as not changing with this nano-TiO2 amendment; herein, we also found that some selected soil properties were unaffected by the treatments. However, we found that nano-TiO2 altered the bacterial community composition and reduced diversity. Nano-TiO2-induced community dissimilarities increased but tended to approach a plateau when soils became drier. Taken together, nano-TiO2 effects on soil bacteria appear to be a result of direct toxicity rather than indirectly through nano-TiO2 affecting soil water and organic matter pools. However, such directs effects of nano-TiO2 on soil bacterial communities are mediated by soil water.

  13. Bacterial community biodiversity in estuaries and its controlling factors:a case study in Chesapeake Bay%河口细菌群落多样性及其控制因素:以切萨皮克湾为例

    Institute of Scientific and Technical Information of China (English)

    阚金军; 孙军

    2011-01-01

    Estuaries are among the most productive and dynamic aquatic ecosystems on earth, due to the mixing of fresh and salt waters and significant recycling of nutrients and organic matters. Sitting in a transitional zone, bacterial communities in an estuary typically harbor representatives of both freshwater and marine groups: Alphaproteobacteria, Betaproteobacteria, Gatnmaproteobacteria, Cyanobacteria (Synechococcus), Bacteroidetes, Actinobacteria, and Verrucomicrobia. In addition, estuaries such as Chesapeake Bay also contain their own unique bacterial signatures including the SARI 1 group, Roseobacter, SAR86, and Actinobacteria subclades, suggesting the ecological adaptation of organisms endemic to the Bay or perhaps, to large temperate estuaries in general. Relative to spatial variations, remarkable seasonal shifts and recurring annual patterns were identified in Chesapeake Bay bacterial communities. Besides water residence time and bacterial growth rate, many other factors are potential driving forces for the microbial diversity and bacterial population dynamics we observed. Temporal variations in bacterial communities were best explained by change in chlorophyll a (Chi a) and water temperature, while other factors such as dissolved oxygen, ammonia, nitrite and nitrate, and viral abundance also appeared to contribute to seasonal succession. Recently, the applications of community-based genomics and postgenomics (transcriptomics and proteomics) have allowed us to study the comprehensive gene diversity and gene expression directly from natural microbial communities. We predict that further studies and analyses of these genes and proteins will deliver new discoveries regarding the composition and function of microbial communities in aquatic environments.%咸淡水的混合和重要营养盐与有机物的再循环,使得河口成为地球上生产力较高而动态变化明显的水生生态系统.一个典型的河口区断面中,细菌群落包含了一些从

  14. Original Article Risk Factors and Bacterial Profile of Suspected ...

    African Journals Online (AJOL)

    2011-08-11

    Aug 11, 2011 ... The aim of this study is to evaluate the bacterial profile, antibiotics susceptibility pattern and associated risk ..... Ako-Nai AK, Torimiro SEA, Lamikanra A and. Ogunbiyi AD ... Neonatal Septicaemia in Ilorin: Bacteria Pathogens.

  15. 1 Prevalence of bacterial vaginosis and associated factors among ...

    African Journals Online (AJOL)

    Collected data were double entered into SPSS statistical database. .... financial assistance from the Embassy of Belgium through the Belgian Technical .... Hill, G.B. (1993) The microbiology of bacterial vaginosis American Journal of Obstetrics ...

  16. Rapid method of determining factors limiting bacterial growth in soil

    OpenAIRE

    Aldén Demoling, Louise; Demoling, Fredrik; Bååth, Erland

    2001-01-01

    A technique to determine which nutrients limit bacterial growth in soil was developed. The method was based on measuring the thymidine incorporation rate of bacteria after the addition of C, N, and P in different combinations to soil samples. First, the thymidine incorporation method was tested in two different soils: an agricultural soil and a forest humus soil. Carbon (as glucose) was found to be the limiting substance for bacterial growth in both of these soils. The effect of adding differ...

  17. The potential of endomycorrhizal fungi in controlling tomato bacterial ...

    African Journals Online (AJOL)

    user

    2012-08-21

    Aug 21, 2012 ... tomato bacterial wilt Ralstonia solanacearum under glasshouse .... MATERIALS AND METHODS ... Stock culture of R. solanacearum was preserved in ..... on grading and pre-packaging of some bacterial wilt resistant brinjal.

  18. The yeast mitochondrial RNA polymerase specificity factor, MTF1, is similar to bacterial sigma factors.

    Science.gov (United States)

    Jang, S H; Jaehning, J A

    1991-11-25

    We have purified the protein that confers selective promoter recognition on the core subunit of the yeast mitochondrial RNA polymerase. The N-terminal sequence of the 43-kDa specificity factor identified it as the product of the MTF1 gene described by Lisowsky and Michaelis (1988). We confirmed that MTF1 encoded the specificity factor by analyzing extracts from a yeast strain bearing a disruption of the gene. The extracts contained normal levels of core RNA polymerase but lacked selective transcription activity; adding the purified 43-kDa protein restored selective transcription. Comparison of the MTF1 protein sequence to the family of bacterial sigma factors has revealed striking similarity to domains identified with--10 promoter recognition, promoter melting, and holoenzyme stability.

  19. 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.

  20. EPIDERMAL GROWTH FACTOR PREVENTS INCREASED PERMEABILITY AND BACTERIAL TRANSLOCATION IN RATS WITH ACUTE PANCREATITIS

    Institute of Scientific and Technical Information of China (English)

    陈冬利; 王为忠; 王俊义

    2001-01-01

    Objective. To evaluate the effects of epidermal growth factor (EGF) on intestinal permeability and bacterial translocation in rats with acute pancreatitis during total parenteral nutrition (TPN). Methods. Thirty-two male Sprague-Dawley rats that underwent injection of 3.5% sodium taurocholate solution into the pancreatic duct were randomly divided into one of the following two groups: (1) received only TPN (control group) or (2) received TPN with EGF at a dose of 0.2 mg· kg-1· day-1 (Egf group). On fifth day of total parenteral nutrition, samples from mesenteric lymph nodes, pancreas, liver and spleen were harvested for cultures. Water, protein and DNA content in jejunal mucosa were determined. D-xylose and fluorescein isothiocyanate (FITC)-dextran were instilled into the lumen of a ligated segament of small intestine. Thirty minutes later, superior mesenteric vein D-xylose and plasma FITC-dextran concentration were measured. Results. Positive cultures in liver and spleen, as well as FITC-dextran concentration in the Egf group were significantly lower than in the control group. Protein and DNA content in jejunal mucosa in the Egf group were significantly higher than in the control group. Conclusion. The results indicate that EGF may prevent increased intestinal permeability and bacterial translocation in rats with acute pancreatitis during TPN.

  1. Bovine milk osteopontin - Targeting bacterial adhesion for biofilm control

    DEFF Research Database (Denmark)

    Kristensen, Mathilde Frost; Meyer, Rikke Louise; Schlafer, Sebastian

    2016-01-01

    Self-performed mechanical tooth cleaning does usually not result in complete biofilm removal, due to the complex oral anatomy and the strong adhesion of the biofilm to the tooth. Therefore, different supportive measures are employed, most of which aim at the chemical eradication of bacteria...... in dental biofilms. As their bactericidal action impacts the entire oral microflora, agents that inhibit biofilm formation without killing bacteria, such as the bovine milk protein osteopontin, have gained increasing attention. Here, we investigate the adhesion of 8 bacterial species associated with dental...... caries to salivary-coated flow-cells in the presence or absence of osteopontin or the control protein caseinoglycomacropeptide (0.32 mM/L). After 1h of flow (9.45 mm/min) at 35 °C, adhering bacteria were quantified by digital image analysis in a total of 692 bright-field images. Experiments were...

  2. Secnidazole Treatment of Bacterial Vaginosis: A Randomized Controlled Trial.

    Science.gov (United States)

    Hillier, Sharon L; Nyirjesy, Paul; Waldbaum, Arthur S; Schwebke, Jane R; Morgan, Franklin G; Adetoro, Nikki A; Braun, Carol J

    2017-08-01

    To evaluate secnidazole as a single oral dose treatment for bacterial vaginosis in a phase 2 randomized, double-blind, placebo-controlled study. In a phase 2, randomized, double-blind, dose-ranging, placebo-controlled study, women with bacterial vaginosis who met all Amsel criteria (discharge; pH 4.7 or greater; 20% or greater clue cells; positive whiff test) were randomized one to one to one at 24 U.S. centers to 1 or 2 g secnidazole compared with placebo. The primary endpoint was clinical cure (normalization of discharge, amine odor, and clue cells) 21-30 days after treatment. Secondary endpoints included microbiologic cure, defined as a Nugent score of 0-3, and therapeutic cure, defined as meeting criteria for both clinical and microbiologic cure. The modified intent to treat was used for efficacy analyses and included all randomized patients who met the enrollment criteria. Assuming a clinical cure rate of 40% in the active groups and 15% in the placebo group, a sample size of 52 patients per group provided approximately 80% power to detect a significant difference between groups (.05 level [two-sided]) using a Cochran-Mantel-Haenszel test. Between May and September 2014, 215 patients were enrolled. In the intent-to-treat population, the clinical cure rate was 65.3% for the 2-g group, 49.3% for the 1-g group, and 19.4% for the placebo group. The modified intent-to-treat population included 188 women (median age 33 years; 32% with four or more bacterial vaginosis episodes in the previous year; 54% black) with baseline Nugent scores 4 or greater. Clinical, microbiologic, and therapeutic cure rates were 67.7%, 40.3%, and 40.3% for 2 g secnidazole and 51.6%, 23.4%, and 21.9% for 1 g secnidazole compared with 17.7%, 6.5%, and 6.5% for placebo, respectively (Pbacterial vaginosis treatment (Pbacterial vaginosis treatment. ClinicalTrials.gov, NCT02147899.

  3. A cell cycle and nutritional checkpoint controlling bacterial surface adhesion.

    Directory of Open Access Journals (Sweden)

    Aretha Fiebig

    2014-01-01

    Full Text Available In natural environments, bacteria often adhere to surfaces where they form complex multicellular communities. Surface adherence is determined by the biochemical composition of the cell envelope. We describe a novel regulatory mechanism by which the bacterium, Caulobacter crescentus, integrates cell cycle and nutritional signals to control development of an adhesive envelope structure known as the holdfast. Specifically, we have discovered a 68-residue protein inhibitor of holdfast development (HfiA that directly targets a conserved glycolipid glycosyltransferase required for holdfast production (HfsJ. Multiple cell cycle regulators associate with the hfiA and hfsJ promoters and control their expression, temporally constraining holdfast development to the late stages of G1. HfiA further functions as part of a 'nutritional override' system that decouples holdfast development from the cell cycle in response to nutritional cues. This control mechanism can limit surface adhesion in nutritionally sub-optimal environments without affecting cell cycle progression. We conclude that post-translational regulation of cell envelope enzymes by small proteins like HfiA may provide a general means to modulate the surface properties of bacterial cells.

  4. Medium-dependent control of the bacterial growth rate.

    Science.gov (United States)

    Ehrenberg, Måns; Bremer, Hans; Dennis, Patrick P

    2013-04-01

    By combining results from previous studies of nutritional up-shifts we here re-investigate how bacteria adapt to different nutritional environments by adjusting their macromolecular composition for optimal growth. We demonstrate that, in contrast to a commonly held view the macromolecular composition of bacteria does not depend on the growth rate as an independent variable, but on three factors: (i) the genetic background (i.e. the strain used), (ii) the physiological history of the bacteria used for inoculation of a given growth medium, and (iii) the kind of nutrients in the growth medium. These factors determine the ribosome concentration and the average rate of protein synthesis per ribosome, and thus the growth rate. Immediately after a nutritional up-shift, the average number of ribosomes in the bacterial population increases exponentially with time at a rate which eventually is attained as the final post-shift growth rate of all cell components. After a nutritional up-shift from one minimal medium to another minimal medium of higher nutritional quality, ribosome and RNA polymerase syntheses are co-regulated and immediately increase by the same factor equal to the increase in the final growth rate. However, after an up-shift from a minimal medium to a medium containing all 20 amino acids, RNA polymerase and ribosome syntheses are no longer coregulated; a smaller rate of synthesis of RNA polymerase is compensated by a gradual increase in the fraction of free RNA polymerase, possibly due to a gradual saturation of mRNA promoters. We have also analyzed data from a recent publication, in which it was concluded that the macromolecular composition in terms of RNA/protein and RNA/DNA ratios is solely determined by the effector molecule ppGpp. Our analysis indicates that this is true only in special cases and that, in general, medium adaptation also depends on factors other than ppGpp.

  5. Inhibition of Quorum Sensing-Controlled Virulence Factors and Biofilm Formation in Pseudomonas aeruginosa by Culture Extract from Novel Bacterial Species of Paenibacillus Using a Rat Model of Chronic Lung Infection

    Directory of Open Access Journals (Sweden)

    Saad Musbah Alasil

    2015-01-01

    Full Text Available Quorum sensing (QS is a key regulator of virulence factors and biofilm formation in Gram-negative bacteria such as Pseudomonas aeruginosa. Microorganisms that inhabit soil are of strategic importance in the discovery of compounds with anti-QS properties. The objective of the study was to test the culture extract of a taxonomically novel species of Paenibacillus strain 139SI for its inhibitory effects on the QS-controlled virulence factors and biofilm formation of Pseudomonas aeruginosa both in vitro and in vivo. The Paenibacillus sp. culture extract was used to test its anti-QS effects on the LasA protease, LasB elastase, pyoverdin production, and biofilm formation of P. aeruginosa as well as evaluate its therapeutic effects on lung bacteriology, pathology, hematological profile, and serum antibody responses of experimental animals in a rat model of chronic lung infection. Results showed significant decrease in the activities of QS-controlled LasA protease, LasB elastase pyoverdin, and biofilm formation of P. aeruginosa caused by the culture extract. Moreover, the extract significantly prolonged the survival times of rats and facilitated the clearance of biofilm infections from infected lungs. In conclusion, the antiquorum sensing effects of culture extract from a novel species of Paenibacillus provide new insights to combat biofilm-associated infections.

  6. Biofouling control: Bacterial quorum quenching versus chlorination in membrane bioreactors.

    Science.gov (United States)

    Weerasekara, Nuwan A; Choo, Kwang-Ho; Lee, Chung-Hak

    2016-10-15

    Biofilm formation (biofouling) induced via cell-to-cell communication (quorum sensing) causes problems in membrane filtration processes. Chorine is one of the most common chemicals used to interfere with biofouling; however, biofouling control is challenging because it is a natural process. This study demonstrates biofouling control for submerged hollow fiber membranes in membrane bioreactors by means of bacterial quorum quenching (QQ) using Rhodococcus sp. BH4 with chemically enhanced backwashing. This is the first trial to bring QQ alongside chlorine injection into practice. A high chlorine dose (100 mg/L as Cl2) to the system is insufficient for preventing biofouling, but addition of the QQ bacterium is effective for disrupting biofouling that cannot be achieved by chlorination alone. QQ reduces the biologically induced metal precipitate and extracellular biopolymer levels in the biofilm, and biofouling is significantly delayed when QQ is applied in addition to chlorine dosing. QQ with chlorine injection gives synergistic effects on reducing physically and chemically reversible fouling resistances while saving substantial filtration energy. Manipulating microbial community functions with chemical treatment is an attractive tool for biofilm dispersal in membrane bioreactors.

  7. A bacteriophage transcription regulator inhibits bacterial transcription initiation by σ-factor displacement.

    Science.gov (United States)

    Liu, Bing; Shadrin, Andrey; Sheppard, Carol; Mekler, Vladimir; Xu, Yingqi; Severinov, Konstantin; Matthews, Steve; Wigneshweraraj, Sivaramesh

    2014-04-01

    Bacteriophages (phages) appropriate essential processes of bacterial hosts to benefit their own development. The multisubunit bacterial RNA polymerase (RNAp) enzyme, which catalyses DNA transcription, is targeted by phage-encoded transcription regulators that selectively modulate its activity. Here, we describe the structural and mechanistic basis for the inhibition of bacterial RNAp by the transcription regulator P7 encoded by Xanthomonas oryzae phage Xp10. We reveal that P7 uses a two-step mechanism to simultaneously interact with the catalytic β and β' subunits of the bacterial RNAp and inhibits transcription initiation by inducing the displacement of the σ(70)-factor on initial engagement of RNAp with promoter DNA. The new mode of interaction with and inhibition mechanism of bacterial RNAp by P7 underscore the remarkable variety of mechanisms evolved by phages to interfere with host transcription.

  8. Alternative Sigma Factors and Their Roles in Bacterial Virulence

    OpenAIRE

    Kazmierczak, Mark J.; Wiedmann, Martin; Boor, Kathryn J.

    2005-01-01

    Sigma factors provide promoter recognition specificity to RNA polymerase holoenzyme, contribute to DNA strand separation, and then dissociate from the core enzyme following transcription initiation. As the regulon of a single sigma factor can be composed of hundreds of genes, sigma factors can provide effective mechanisms for simultaneously regulating expression of large numbers of prokaryotic genes. One newly emerging field is identification of the specific roles of alternative sigma factors...

  9. Control of dialysis water by microbial contamination and bacterial endotoxin tests

    Directory of Open Access Journals (Sweden)

    Fesem BAŞARI

    2012-01-01

    Full Text Available Objective: The aim of this study was to evaluate the microbial contamination and bacterial endotoxin levels in dialysis water samples sent to the Water and Food Microbiology Laboratory of the Adana Hygiene Institute Refik Saydam Hygiene Center, and to assess factors that might influence the results of these tests.Method: Two hundred fourty five dialysis water samples sent to the laboratory between January 2009 and December 2010 were tested; all of them for microbial contamination and 198 of them for bacterial endotoxin levels. Microbial contamination was evaluated by using the Plate Count Agar (PCA method while the Limulus Amoebocyte Lysate (LAL assay was used for the detection of bacterial endotoxins. The results were evaluated according to the criteria of the “Directives on the Water Purification Systems” and “the European Pharmacopoeia”. To compare the annual differences, the chi-square test was used for statistical evaluation and results with p0.05in 2010. On the other hand, in 26.7% of the dialysiswater samples the levels of bacterial endotoxinswas higher than 0.25 İU/ml in 2009, this percentagedropped to 16.5% in 2010 (p>0.05. During 2009-2010,245 microbial contamination tests were performedand in 20 (8.2% of the samples the TAMC values werehigher than 100 CFU/ml, while in 43 (21.7% out of198 of the samples the bacterial endotoxin levelswere higher than 0.25 İU/ml. Out of 20 in 43 samples,a bacterial endotoxin levels were >0.25 İU/ml werealso found as microbiologically contaminated ( >100CFU/ml, while in remaining 23 samples the level was<100 CFU/ml. There were no statistically significantdifferences in the percentages of positives found in2009 and 2010.Conclusion: The results of our study indicatethat the detection of endotoxins is a complementaryfactor to microbial contamination in the bacteriologicalmonitoring of dialysis waters. We recommend thatlevel of endotoxin should be taken into accountwhen the bacterial contamination

  10. Plumage bacterial assemblages in a breeding wild passerine: relationships with ecological factors and body condition.

    Science.gov (United States)

    Saag, Pauli; Tilgar, Vallo; Mänd, Raivo; Kilgas, Priit; Mägi, Marko

    2011-05-01

    Microorganisms have been shown to play an important role in shaping the life histories of animals, and it has recently been suggested that feather-degrading bacteria influence the trade-off between parental effort and self-preening behavior in birds. We studied a wild breeding population of great tits (Parus major) to explore habitat-, seasonal-, and sex-related variation in feather-degrading and free-living bacteria inhabiting the birds' yellow ventral feathers and to investigate associations with body condition. The density and species richness of bacterial assemblages was studied using flow cytometry and ribosomal intergenic spacer analysis. The density of studied bacteria declined between the nest-building period and the first brood. The number of bacterial phylotypes per bird was higher in coniferous habitat, while bacterial densities were higher in deciduous habitat. Free-living bacterial density was positively correlated with female mass; conversely, there was a negative correlation between attached bacterial density and female mass during the period of peak reproductive effort. Bacterial species richness was sex dependent, with more diverse bacterial assemblages present on males than females. Thus, this study revealed that bacterial assemblages on the feathers of breeding birds are affected both by life history and ecological factors and are related to body condition.

  11. Biotypes and virulence factors of Gardnerella vaginalis isolated from cases of bacterial vaginosis

    OpenAIRE

    Udayalaxmi, J.; Bhat, G. K.; S Kotigadde

    2011-01-01

    The present study was conducted to correlate the biotypes of Gardnerella vaginalis strains isolated from cases of bacterial vaginosis and their virulence factors. Thirty-two strains of G. vaginalis isolated from cases of bacterial vaginosis were biotyped. Adherence to vaginal epithelial cells, biofilm production, surface hydrophobicity, phospholipase C and protease activity were tested on these isolates. Biotype 1 was the most prevalent (8; 25%), followed by biotype 2 (7; 21.9%) and biotypes ...

  12. Biotypes and virulence factors of Gardnerella vaginalis isolated from cases of bacterial vaginosis.

    Science.gov (United States)

    Udayalaxmi, J; Bhat, G K; Kotigadde, S

    2011-01-01

    The present study was conducted to correlate the biotypes of Gardnerella vaginalis strains isolated from cases of bacterial vaginosis and their virulence factors. Thirty-two strains of G. vaginalis isolated from cases of bacterial vaginosis were biotyped. Adherence to vaginal epithelial cells, biofilm production, surface hydrophobicity, phospholipase C and protease activity were tested on these isolates. Biotype 1 was the most prevalent (8; 25%), followed by biotype 2 (7; 21.9%) and biotypes 5 and 8 (5; 15.6%). We did not find any statistical correlation between G. vaginalis biotypes and its virulence factors. Virulence factors expressed by G. vaginalis were not associated with a single biotype.

  13. Biotypes and virulence factors of Gardnerella vaginalis isolated from cases of bacterial vaginosis

    Directory of Open Access Journals (Sweden)

    J Udayalaxmi

    2011-01-01

    Full Text Available The present study was conducted to correlate the biotypes of Gardnerella vaginalis strains isolated from cases of bacterial vaginosis and their virulence factors. Thirty-two strains of G. vaginalis isolated from cases of bacterial vaginosis were biotyped. Adherence to vaginal epithelial cells, biofilm production, surface hydrophobicity, phospholipase C and protease activity were tested on these isolates. Biotype 1 was the most prevalent (8; 25%, followed by biotype 2 (7; 21.9% and biotypes 5 and 8 (5; 15.6%. We did not find any statistical correlation between G. vaginalis biotypes and its virulence factors. Virulence factors expressed by G. vaginalis were not associated with a single biotype.

  14. Clavanin bacterial sepsis control using a novel methacrylate nanocarrier

    Directory of Open Access Journals (Sweden)

    Saúde ACM

    2014-10-01

    Full Text Available Amanda CM Saúde,1 Alicia S Ombredane,1 Osmar N Silva,1 João ARG Barbosa,1,2 Susana E Moreno,3 Ana Claudia Guerra Araujo,4 Rosana Falcão,4 Luciano P Silva,4 Simoni C Dias,1 Octávio L Franco1,3 1Programa de Pós Graduação em Ciências Genômicas e Biotecnologia, Centro de Análises Proteômicas e Bioquímicas, Universidade Católica de Brasília, Brasília, FD, Brazil; 2Laboratório de Biofísica-Departamento de Biologia Celular-IB, Universidade de Brasília – UNB, DF, Brazil; 3Universidade Católica Dom Bosco – UCDB, Campo Grande, MS, Brazil; 4Empresa Brasileira de Pesquisa Agropecuária – EMBRAPA – Recursos Genéticos e Biotecnologia, Brasília, DF, Brazil Abstract: Controlling human pathogenic bacteria is a worldwide problem due to increasing bacterial resistance. This has prompted a number of studies investigating peptides isolated from marine animals as a possible alternative for control of human pathogen infections. Clavanins are antimicrobial peptides isolated from the marine tunicate Styela clava, showing 23 amino acid residues in length, cationic properties, and also high bactericidal activity. In spite of clear benefits from the use of peptides, currently 95% of peptide properties have limited pharmaceutical applicability, such as low solubility and short half-life in the circulatory system. Here, nanobiotechnology was used to encapsulate clavanin A in order to develop nanoantibiotics against bacterial sepsis. Clavanin was nanostructured using EUDRAGIT® L 100-55 and RS 30 D solution (3:1 w:w. Atomic force, scanning electron microscopy and dynamic light scattering showed nanoparticles ranging from 120 to 372 nm in diameter, with a zeta potential of -7.16 mV and a polydispersity index of 0.123. Encapsulation rate of 98% was assessed by reversed-phase chromatography. In vitro bioassays showed that the nanostructured clavanin was partially able to control development of Staphylococcus aureus, Klebsiella pneumoniae, and

  15. Prevalence of Small Intestinal Bacterial Overgrowth among Chronic Pancreatitis Patients: A Case-Control Study

    Science.gov (United States)

    Bouchard, Simon; Sidani, Sacha

    2016-01-01

    Background. Patients with chronic pancreatitis (CP) exhibit numerous risk factors for the development of small intestinal bacterial overgrowth (SIBO). Objective. To determine the prevalence of SIBO in patients with CP. Methods. Prospective, single-centre case-control study conducted between January and September 2013. Inclusion criteria were age 18 to 75 years and clinical and radiological diagnosis of CP. Exclusion criteria included history of gastric, pancreatic, or intestinal surgery or significant clinical gastroparesis. SIBO was detected using a standard lactulose breath test (LBT). A healthy control group also underwent LBT. Results. Thirty-one patients and 40 controls were included. The patient group was significantly older (53.8 versus 38.7 years; P PERT), and severity of symptoms. Conclusion. The prevalence of SIBO detected using LBT was high among patients with CP. There was no association between clinical features and the risk for SIBO. PMID:27446865

  16. Keratinocyte growth factor-2 inhibits bacterial infection with Pseudomonas aeruginosa pneumonia in a mouse model.

    Science.gov (United States)

    Feng, Nana; Wang, Qin; Zhou, Jian; Li, Jing; Wen, Xiaoxing; Chen, Shujing; Zhu, Zhenhua; Bai, Chunxue; Song, Yuanlin; Li, Huayin

    2016-01-01

    To determine protective effects of concurrent administration of Keratinocyte growth factor-2 (KGF-2) with Pseudomonas aeruginosa (P. aeruginosa) inoculation on the induced pneumonia. KGF-2 (5 mg/kg) was concurrently administered into the left lobe of 55 mice with P. aeruginosa PAO1 (5 × 10(6) CFU, half-lethal dose); 55 mice in the control group were concurrently administered PBS with the PAO1. We detected and analyzed: body temperature; amount of P. aeruginosa in homogenates; count of total number of nucleated cells and of mononuclear macrophages; protein concentration in bronchoalveolar lavage fluid (BALF); lung wet-to-dry weight ratio; cytokines in BALF and blood; and lung morphology. To study survival rate, concurrent administration of KGF-2 (experimental group) versus PBS (control) with a lethal dose of PAO1 (1 × 10(7) CFU was performed, and survivorship was documented for 7 days post-inoculation. The bacterial CFU in lung homogenates was significantly decreased in the KGF-2 group compared to the control group. There were significantly more mononuclear macrophages in the BALF from the KGF-2 group than from the control group (p model with P. aeruginosa pneumonia. Copyright © 2015 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  17. The interaction between bacterial transcription factors and RNA polymerase during the transition from initiation to elongation.

    Science.gov (United States)

    Yang, Xiao; Lewis, Peter J

    2010-01-01

    There are three stages of transcription: initiation, elongation and termination, and traditionally there has been a clear distinction between the stages. The specificity factor sigma is completely released from bacterial RNA polymerase after initiation, and then recycled for another round of transcription. Elongation factors then associate with the polymerase followed by termination factors (where necessary). These factors dissociate prior to initiation of a new round of transcription. However, there is growing evidence suggesting that sigma factors can be retained in the elongation complex. The structure of bacterial RNAP in complex with an essential elongation factor NusA has recently been published, which suggested rather than competing for the major σ binding site, NusA binds to a discrete region on RNAP. A model was proposed to help explain the way in which both factors could be associated with RNAP during the transition from transcription initiation to elongation.

  18. Correlation of bacterial vaginosis with preterm labour: a case control study

    Directory of Open Access Journals (Sweden)

    Waseeqa Nigeen

    2015-12-01

    Conclusions: Bacterial vaginosis is significantly more prevalent in women with preterm labour. Whiff test can be used alone in centres where the patient load is too high. Illiteracy is a risk factor that can be modified to bring down incidence of bacterial vaginosis. [Int J Reprod Contracept Obstet Gynecol 2015; 4(6.000: 1868-1874

  19. Effects of Host Plant Factors on the Bacterial Communities Associated with Two Whitefly Sibling Species.

    Science.gov (United States)

    Su, Ming-Ming; Guo, Lei; Tao, Yun-Li; Zhang, You-Jun; Wan, Fang-Hao; Chu, Dong

    2016-01-01

    Although discrepancy in the specific traits and ecological characteristics of Bemisia tabaci between species are partially attributed to the B. tabaci-associated bacteria, the factors that affect the diversity of B. tabaci-associated bacteria are not well-understood. We used the metagenomic approach to characterize the B. tabaci-associated bacterial community because the approach is an effective tool to identify the bacteria. To investigate the effects of the host plant and a virus, tomato yellow leaf curl virus (TYLCV), on the bacterial communities of B. tabaci sibling species B and Q, we analyzed the bacterial communities associated with whitefly B and Q collected from healthy cotton, healthy tomato, and TYLCV-infected tomato. The analysis used miseq-based sequencing of a variable region of the bacterial 16S rDNA gene. For the bacteria associated with B. tabaci, we found that the influence of the host plant species was greater than that of the whitefly cryptic species. With further analysis of host plants infected with the TYLCV, the virus had no significant effects on the B. tabaci-associated bacterial community. The effects of different plant hosts and TYLCV-infection on the diversity of B. tabaci-associated bacterial communities were successfully analyzed in this study. To explain why B. tabaci sibling species with different host ranges differ in performance, the analysis of the bacterial community may be essential to the explanation.

  20. Prevalence of bacterial vaginosis and its risk factors in HIV/AIDSpatients with abnormal vaginal discharge

    Institute of Scientific and Technical Information of China (English)

    Samuel Nwadioha; Daniel Egah; Edmond Banwat; Julie Egesie; Ifeanyi Onwuezobe

    2011-01-01

    Objective:To determine the prevalence of bacterial vaginosis in theHIV/AIDS patients of primary health care clinics in Jos Plateau state, Nigeria.Methods: Female genital swabs were collected from primary health care centers, Jos and analyzed by microscopy, culture,etc. in Jos University Teaching Hospital from December2006 to December2007. Data on epidemiologic indices were collected, using structured interviewer-administered questionnaires.Results:The incidence of bacterial vaginosis in the study was 28%(n=196/700). Among theHIV/AIDS group, the bacterial vaginosis incidence was36% (n=126/350), while in the control (non-HIV patients) group, the rate was20% (70/350) with a statistically significant difference at 95 percent confidence level(P<0.05) .HIV/AIDSand non-HIV (control) patients contributed64% (n=126/196) and36%(n=70/196), respectively. The risks to bacterial vaginosis included vaginal douching with disinfectant/detergent constituted(60%), poor use of condom40%, a median age of26years, and a median number of3 sex partners per week.Conclusions: There was a significant statistical difference in prevalence of bacterial vaginosis between theHIV/AIDS group and non-HIV(control) group of patients in the study. Risk behaviors that promote the incidence of bacterial vaginosis should be especially paid attention.

  1. Intrinsic factors of Peltigera lichens influence the structure of the associated soil bacterial microbiota.

    Science.gov (United States)

    Leiva, Diego; Clavero-León, Claudia; Carú, Margarita; Orlando, Julieta

    2016-11-01

    Definition of lichens has evolved from bi(tri)partite associations to multi-species symbioses, where bacteria would play essential roles. Besides, although soil bacterial communities are known to be affected by edaphic factors, when lichens grow upon them these could become less preponderant. We hypothesized that the structure of both the lichen microbiota and the microbiota in the soil underneath lichens is shaped by lichen intrinsic and extrinsic factors. In this work, intrinsic factors corresponded to mycobiont and cyanobiont identities of Peltigera lichens, metabolite diversity and phenoloxidase activity and extrinsic factors involved the site of the forest where lichens grow. Likewise, the genetic and metabolic structure of the lichen and soil bacterial communities were analyzed by fingerprinting. Among the results, metabolite diversity was inversely related to the genetic structure of bacterial communities of lichens and soils, highlighting the far-reaching effect of these substances; while phenoloxidase activity was inversely related to the metabolic structure only of the lichen bacterial microbiota, presuming a more limited effect of the products of these enzymes. Soil bacterial microbiota was different depending on the site and, strikingly, according to the cyanobiont present in the lichen over them, which could indicate an influence of the photobiont metabolism on the availability of soil nutrients. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Risk factors for bacterial vaginosis in pregnancy: a population-based study on Danish women

    DEFF Research Database (Denmark)

    Thorsen, Poul; Vogel, Ida; Molsted, Kirsten

    2006-01-01

    Background. No larger population-based study of bacterial vaginosis in pregnancy has previously been available. The objective of this study was to examine risk factors for bacterial vaginosis in pregnancy. Design. From a prospective population-based cohort of 3,596 eligible pregnant women, 2......,927 (81.4%) completed the study. Methods. Women were asked to participate in this study at their first prenatal visit at 17 gestational weeks (range 7+/324+/0). Samples from the genital tract were taken at enrolment. Bacterial vaginosis was determined by Amsel's clinical criteria (3 out of 4: pH>/4.......5, homogenous discharge, clue cells, and positive amine test). Data were collected from three questionnaires completed during the second and third trimesters and correlated with the diagnosis of bacterial vaginosis. Crude and adjusted relative risks (reproductive, medical, behavioral, sexual...

  3. Role of granulocyte colony-stimulating factor in paclitaxel-induced intestinal barrier breakdown and bacterial translocation in rats

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chi; XU Yang-guang; DUAN Xue-ning; LIU Yin-hua; ZHAO Jian-xin; XU Ling; YE Jing-ming

    2011-01-01

    Background Chemotherapy causes breakdown of the intestinal barrier, which may lead to bacterial translocation. Paclitaxel, an anti-tubulin agent, has many side effects; however, its effect on the intestinal barrier is unknown. Previous studies show that granulocyte colony-stimulating factor (G-CSF) plays an important role in modulating intestinal barrier function, but these studies are not conclusive. Here, we investigated the effects of paclitaxel on the intestinal barrier, and whether G-CSF could prevent paclitaxel-induced bacterial translocation.Methods Twenty-four male Sprague-Dawley rats were divided into three groups: control group, paclitaxel group and paclitaxel + G-CSF group. Intestinal permeability was measured by the urinary excretion rates of lactulose and mannitol administered by gavage. The mesenteric lymph nodes, spleen and liver were aseptically harvested for bacterial culture. Endotoxin levels and white blood cell (WBC) counts were measured and bacterial quantification performed using relative real-time PCR. Jejunum samples were also obtained for histological observation. Intestinal apoptosis was evaluated using a fragmented DNA assay and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP)-biotin nick end-labeling staining. One-way analysis of variance and Fisher's exact test were used to compare differences between groups.Results Paclitaxel induced apoptosis in 12.5% of jejunum villus cells, which was reduced to 3.8% by G-CSF treatment. Apoptosis in the control group was 0.6%. Paclitaxel treatment also resulted in villus atrophy, increased intestinal permeability and a reduction in the WBC count. G-CSF treatment resulted in increased villus height and returned WBC counts to normal levels. No bacterial translocation was detected in the control group, whereas 6/8,8/8, and 8/8 rats in the paclitaxel group were culture-positive in the liver, spleen and mesenteric lymph nodes, respectively. Bacterial translocation was

  4. Associations of the vaginal microbiota with HIV infection, bacterial vaginosis, and demographic factors.

    Science.gov (United States)

    Chehoud, Christel; Stieh, Daniel J; Bailey, Aubrey G; Laughlin, Alice L; Allen, Shannon A; McCotter, Kerrie L; Sherrill-Mix, Scott A; Hope, Thomas J; Bushman, Frederic D

    2017-04-24

    We sought to investigate the effects of HIV infection on the vaginal microbiota and associations with treatment and demographic factors. We thus compared vaginal microbiome samples from HIV-infected (HIV+) and HIV-uninfected (HIV-) women collected at two Chicago area hospitals. We studied vaginal microbiome samples from 178 women analyzed longitudinally (n = 324 samples) and collected extensive data on clinical status and demographic factors. We used 16S rRNA gene sequencing to characterize the bacterial lineages present, then UniFrac, Shannon diversity, and other measures to compare community structure with sample metadata. Differences in microbiota measures were modest in the comparison of HIV+ and HIV- samples, in contrast to several previous studies, consistent with effective antiretroviral therapy. Proportions of healthy Lactobacillus species were not higher in HIV- patients overall, but were significantly higher when analyzed within each hospital in isolation. Rates of bacterial vaginosis were higher among African-American women and HIV+ women. Bacterial vaginosis was associated with higher frequency of HIV+. Unexpectedly, African-American women were more likely to switch bacterial vaginosis status between sampling times; switching was not associated with HIV+ status. The influence of HIV infection on the vaginal microbiome was modest for this cohort of well suppressed urban American women, consistent with effective antiretroviral therapy. HIV+ was found to be associated with bacterial vaginosis. Although bacterial vaginosis has previously been associated with HIV transmission, most of the women studied here became HIV+ many years before our test for bacterial vaginosis, thus implicating additional mechanisms linking HIV infection and bacterial vaginosis.

  5. You Are What You Eat: Metabolic Control of Bacterial Division.

    Science.gov (United States)

    Monahan, Leigh G; Harry, Elizabeth J

    2016-03-01

    Fluctuations in nutrient availability are a fact of life for bacterial cells in the 'wild'. To survive and compete, bacteria must rapidly modulate cell-cycle processes to accommodate changing nutritional conditions and concomitant changes in cell growth. Our understanding of how this is achieved has been transformed in recent years, with cellular metabolism emerging as a central player. Several metabolic enzymes, in addition to their normal catalytic functions, have been shown to directly modulate cell-cycle processes in response to changing nutrient levels. Here we focus on cell division, the final event in the bacterial cell cycle, and discuss recent compelling evidence connecting division regulation to nutritional status and metabolic activity.

  6. Biological Stability of Drinking Water: Controlling Factors, Methods, and Challenges

    KAUST Repository

    Prest, Emmanuelle I.

    2016-02-01

    Biological stability of drinking water refers to the concept of providing consumers with drinking water of same microbial quality at the tap as produced at the water treatment facility. However, uncontrolled growth of bacteria can occur during distribution in water mains and premise plumbing, and can lead to hygienic (e.g., development of opportunistic pathogens), aesthetic (e.g., deterioration of taste, odor, color) or operational (e.g., fouling or biocorrosion of pipes) problems. Drinking water contains diverse microorganisms competing for limited available nutrients for growth. Bacterial growth and interactions are regulated by factors, such as (i) type and concentration of available organic and inorganic nutrients, (ii) type and concentration of residual disinfectant, (iii) presence of predators, such as protozoa and invertebrates, (iv) environmental conditions, such as water temperature, and (v) spatial location of microorganisms (bulk water, sediment, or biofilm). Water treatment and distribution conditions in water mains and premise plumbing affect each of these factors and shape bacterial community characteristics (abundance, composition, viability) in distribution systems. Improved understanding of bacterial interactions in distribution systems and of environmental conditions impact is needed for better control of bacterial communities during drinking water production and distribution. This article reviews (i) existing knowledge on biological stability controlling factors and (ii) how these factors are affected by drinking water production and distribution conditions. In addition, (iii) the concept of biological stability is discussed in light of experience with well-established and new analytical methods, enabling high throughput analysis and in-depth characterization of bacterial communities in drinking water. We discussed, how knowledge gained from novel techniques will improve design and monitoring of water treatment and distribution systems in order

  7. Biological Stability of Drinking Water: Controlling Factors, Methods, and Challenges

    Science.gov (United States)

    Prest, Emmanuelle I.; Hammes, Frederik; van Loosdrecht, Mark C. M.; Vrouwenvelder, Johannes S.

    2016-01-01

    Biological stability of drinking water refers to the concept of providing consumers with drinking water of same microbial quality at the tap as produced at the water treatment facility. However, uncontrolled growth of bacteria can occur during distribution in water mains and premise plumbing, and can lead to hygienic (e.g., development of opportunistic pathogens), aesthetic (e.g., deterioration of taste, odor, color) or operational (e.g., fouling or biocorrosion of pipes) problems. Drinking water contains diverse microorganisms competing for limited available nutrients for growth. Bacterial growth and interactions are regulated by factors, such as (i) type and concentration of available organic and inorganic nutrients, (ii) type and concentration of residual disinfectant, (iii) presence of predators, such as protozoa and invertebrates, (iv) environmental conditions, such as water temperature, and (v) spatial location of microorganisms (bulk water, sediment, or biofilm). Water treatment and distribution conditions in water mains and premise plumbing affect each of these factors and shape bacterial community characteristics (abundance, composition, viability) in distribution systems. Improved understanding of bacterial interactions in distribution systems and of environmental conditions impact is needed for better control of bacterial communities during drinking water production and distribution. This article reviews (i) existing knowledge on biological stability controlling factors and (ii) how these factors are affected by drinking water production and distribution conditions. In addition, (iii) the concept of biological stability is discussed in light of experience with well-established and new analytical methods, enabling high throughput analysis and in-depth characterization of bacterial communities in drinking water. We discussed, how knowledge gained from novel techniques will improve design and monitoring of water treatment and distribution systems in order

  8. Biological Stability of Drinking Water: Controlling Factors, Methods, and Challenges.

    Science.gov (United States)

    Prest, Emmanuelle I; Hammes, Frederik; van Loosdrecht, Mark C M; Vrouwenvelder, Johannes S

    2016-01-01

    Biological stability of drinking water refers to the concept of providing consumers with drinking water of same microbial quality at the tap as produced at the water treatment facility. However, uncontrolled growth of bacteria can occur during distribution in water mains and premise plumbing, and can lead to hygienic (e.g., development of opportunistic pathogens), aesthetic (e.g., deterioration of taste, odor, color) or operational (e.g., fouling or biocorrosion of pipes) problems. Drinking water contains diverse microorganisms competing for limited available nutrients for growth. Bacterial growth and interactions are regulated by factors, such as (i) type and concentration of available organic and inorganic nutrients, (ii) type and concentration of residual disinfectant, (iii) presence of predators, such as protozoa and invertebrates, (iv) environmental conditions, such as water temperature, and (v) spatial location of microorganisms (bulk water, sediment, or biofilm). Water treatment and distribution conditions in water mains and premise plumbing affect each of these factors and shape bacterial community characteristics (abundance, composition, viability) in distribution systems. Improved understanding of bacterial interactions in distribution systems and of environmental conditions impact is needed for better control of bacterial communities during drinking water production and distribution. This article reviews (i) existing knowledge on biological stability controlling factors and (ii) how these factors are affected by drinking water production and distribution conditions. In addition, (iii) the concept of biological stability is discussed in light of experience with well-established and new analytical methods, enabling high throughput analysis and in-depth characterization of bacterial communities in drinking water. We discussed, how knowledge gained from novel techniques will improve design and monitoring of water treatment and distribution systems in order

  9. Biological stability of drinking water: controlling factors, methods and challenges

    Directory of Open Access Journals (Sweden)

    Emmanuelle ePrest

    2016-02-01

    Full Text Available Biological stability of drinking water refers to the concept of providing consumers with drinking water of same microbial quality at the tap as produced at the water treatment facility. However, uncontrolled growth of bacteria can occur during distribution in water mains and premise plumbing, and can lead to hygienic (e.g. development of opportunistic pathogens, aesthetic (e.g. deterioration of taste, odour, colour or operational (e.g. fouling or biocorrosion of pipes problems. Drinking water contains diverse microorganisms competing for limited available nutrients for growth. Bacterial growth and interactions are regulated by factors such as (i type and concentration of available organic and inorganic nutrients, (ii type and concentration of residual disinfectant, (iii presence of predators such as protozoa and invertebrates, (iv environmental conditions such as water temperature, and (v spatial location of microorganisms (bulk water, sediment or biofilm. Water treatment and distribution conditions in water mains and premise plumbing affect each of these factors and shape bacterial community characteristics (abundance, composition, viability in distribution systems. Improved understanding of bacterial interactions in distribution systems and of environmental conditions impact is needed for better control of bacterial communities during drinking water production and distribution. This article reviews (i existing knowledge on biological stability controlling factors and (ii how these factors are affected by drinking water production and distribution conditions. In addition, (iii the concept of biological stability is discussed in light of experience with well-established and new analytical methods, enabling high throughput analysis and in-depth characterization of bacterial communities in drinking water. We discuss how knowledge gained from novel techniques will improve design and monitoring of water treatment and distribution systems in order to

  10. Sustainable control of pea bacterial blight : approaches for durable genetic resistance and biocontrol by endophytic bacteria

    NARCIS (Netherlands)

    Elvira-Recuenco, M.

    2000-01-01

    Key-words: bacterial blight, biological control, biodiversity, endophytic bacteria, L-form, pea, PDRl retrotransposon, Pisum sativum, Pisum abyssinicum, Pseudomonas syringae pv. pisi, race specific resistance, race non-specific resistance, Spanish landraces.Pea bacterial blight (Pseudom

  11. Fed-Batch Production of Bacterial Ghosts Using Dielectric Spectroscopy for Dynamic Process Control.

    Science.gov (United States)

    Meitz, Andrea; Sagmeister, Patrick; Lubitz, Werner; Herwig, Christoph; Langemann, Timo

    2016-03-24

    The Bacterial Ghost (BG) platform technology evolved from a microbiological expression system incorporating the ϕX174 lysis gene E. E-lysis generates empty but structurally intact cell envelopes (BGs) from Gram-negative bacteria which have been suggested as candidate vaccines, immunotherapeutic agents or drug delivery vehicles. E-lysis is a highly dynamic and complex biological process that puts exceptional demands towards process understanding and control. The development of a both economic and robust fed-batch production process for BGs required a toolset capable of dealing with rapidly changing concentrations of viable biomass during the E-lysis phase. This challenge was addressed using a transfer function combining dielectric spectroscopy and soft-sensor based biomass estimation for monitoring the rapid decline of viable biomass during the E-lysis phase. The transfer function was implemented to a feed-controller, which followed the permittivity signal closely and was capable of maintaining a constant specific substrate uptake rate during lysis phase. With the described toolset, we were able to increase the yield of BG production processes by a factor of 8-10 when compared to currently used batch procedures reaching lysis efficiencies >98%. This provides elevated potentials for commercial application of the Bacterial Ghost platform technology.

  12. Fed-Batch Production of Bacterial Ghosts Using Dielectric Spectroscopy for Dynamic Process Control

    Directory of Open Access Journals (Sweden)

    Andrea Meitz

    2016-03-01

    Full Text Available The Bacterial Ghost (BG platform technology evolved from a microbiological expression system incorporating the ϕX174 lysis gene E. E-lysis generates empty but structurally intact cell envelopes (BGs from Gram-negative bacteria which have been suggested as candidate vaccines, immunotherapeutic agents or drug delivery vehicles. E-lysis is a highly dynamic and complex biological process that puts exceptional demands towards process understanding and control. The development of a both economic and robust fed-batch production process for BGs required a toolset capable of dealing with rapidly changing concentrations of viable biomass during the E-lysis phase. This challenge was addressed using a transfer function combining dielectric spectroscopy and soft-sensor based biomass estimation for monitoring the rapid decline of viable biomass during the E-lysis phase. The transfer function was implemented to a feed-controller, which followed the permittivity signal closely and was capable of maintaining a constant specific substrate uptake rate during lysis phase. With the described toolset, we were able to increase the yield of BG production processes by a factor of 8–10 when compared to currently used batch procedures reaching lysis efficiencies >98%. This provides elevated potentials for commercial application of the Bacterial Ghost platform technology.

  13. Bacterial sigma factors: a historical, structural, and genomic perspective.

    Science.gov (United States)

    Feklístov, Andrey; Sharon, Brian D; Darst, Seth A; Gross, Carol A

    2014-01-01

    Transcription initiation is the crucial focal point of gene expression in prokaryotes. The key players in this process, sigma factors (σs), associate with the catalytic core RNA polymerase to guide it through the essential steps of initiation: promoter recognition and opening, and synthesis of the first few nucleotides of the transcript. Here we recount the key advances in σ biology, from their discovery 45 years ago to the most recent progress in understanding their structure and function at the atomic level. Recent data provide important structural insights into the mechanisms whereby σs initiate promoter opening. We discuss both the housekeeping σs, which govern transcription of the majority of cellular genes, and the alternative σs, which direct RNA polymerase to specialized operons in response to environmental and physiological cues. The review concludes with a genome-scale view of the extracytoplasmic function σs, the most abundant group of alternative σs.

  14. Differences in bacterial saliva profile between periodontitis patients and a control cohort

    DEFF Research Database (Denmark)

    Belstrøm, Daniel; Fiehn, Nils-Erik; Nielsen, Claus H

    2014-01-01

    AIM: Periodontitis is a multifactorial disease in which subgingival bacteria play an important role in the pathogenesis of the disease. The objective of this study was to determine if periodontitis is associated with a characteristic salivary bacterial profile. This was accomplished by comparing...... the bacterial profile of saliva from subjects with chronic periodontitis with that of saliva from a control cohort. MATERIALS AND METHODS: Stimulated saliva samples from 139 chronic periodontitis patients and 447 samples from a control cohort were analysed using the Human Oral Microbe Identification Microarray...... component analysis was used to visualize bacterial community profiles obtained by the HOMIM. RESULTS: Eight bacterial taxa, including putative periodontal pathogens as Parvimonas micra and Filifactor alocis, and four bacterial clusters were identified statistically more frequently and at higher levels...

  15. Fatores de risco para meningite bacteriana no recém-nascido Risk factors for bacterial meningitis in the newborn

    Directory of Open Access Journals (Sweden)

    Vera Lúcia Jornada Krebs

    2004-09-01

    Full Text Available O objetivo do estudo é descrever os fatores de risco para meningite bacteriana em recém-nascidos e analisar a prevalência destes fatores, considerando-se a presença ou não de baixo peso ao nascimento. Foram analisados 50 recém-nascidos com meningite bacteriana, excluindo-se aqueles com meningomielocele ou infecção congênita. Na análise estatística utilizou-se o teste exato de Fisher, considerando-se significantes os valores de p The aim of this study is to describe the risk factors for bacterial meningitis in newborns, and to analyze the prevalence of these factors, considering or not the low birth weight presence. Fifty newborns with bacterial meningitis were analyzed, excluding the ones with meningomyelocele or congenital infection. In the statistical analysis, the Fisher's exact test was used, considering significant the p < 0.05 values. This study has shown that prematurity, low birth weight and presence of previous infectious diseases in the newborn or in the mother were important risk factors for meningitis. Among low birth weight newborns, invasive procedures, especially tracheal intubation, use of central venous catheter and previous use of antibiotics, were significantly associated to the meningitis occurrence. These results indicate that the improvement in the prenatal care and in the hospital infection control are measures of high importance in the decrease of the incidence of neonatal bacterial meningitis.

  16. Home Life: Factors Structuring the Bacterial Diversity Found within and between Homes

    Science.gov (United States)

    2013-01-01

    Most of our time is spent indoors where we are exposed to a wide array of different microorganisms living on surfaces and in the air of our homes. Despite their ubiquity and abundance, we have a limited understanding of the microbial diversity found within homes and how the composition and diversity of microbial communities change across different locations within the home. Here we examined the diversity of bacterial communities found in nine distinct locations within each of forty homes in the Raleigh-Durham area of North Carolina, USA, using high-throughput sequencing of the bacterial 16S rRNA gene. We found that each of the sampled locations harbored bacterial communities that were distinct from one another with surfaces that are regularly cleaned typically harboring lower levels of diversity than surfaces that are cleaned infrequently. These location-specific differences in bacterial communities could be directly related to usage patterns and differences in the likely sources of bacteria dispersed onto these locations. Finally, we examined whether the variability across homes in bacterial diversity could be attributed to outdoor environmental factors, indoor habitat structure, or the occupants of the home. We found that the presence of dogs had a significant effect on bacterial community composition in multiple locations within homes as the homes occupied by dogs harbored more diverse communities and higher relative abundances of dog-associated bacterial taxa. Furthermore, we found a significant correlation between the types of bacteria deposited on surfaces outside the home and those found inside the home, highlighting that microbes from outside the home can have a direct effect on the microbial communities living on surfaces within our homes. Together this work provides the first comprehensive analysis of the microbial communities found in the home and the factors that shape the structure of these communities both within and between homes. PMID:23717552

  17. Interleukin-10 and soluble tumor necrosis factor receptors in cerebrospinal fluid of children with bacterial meningitis

    NARCIS (Netherlands)

    Kornelisse, R.F.; Savelkoul, H.F.J.; Mulder, P.H.G.; Suur, M.H.; Straaten, van der P.J.C.; Heijden, van der A.J.; Sukhai, R.N.; Hählen, K.; Neijens, H.J.; Groot, de R.

    1996-01-01

    The antiinflammatory mediators interleukin (IL)-10 and soluble tumor necrosis factor (TNF) receptors p55 (sTNFR-55) and sTNFR-75 in cerebrospinal fluid (CSF) from 37 children with bacterial meningitis were studied. CSF concentrations of IL-10, sTNFR-55, and sTNFR-75 and of the proinflammatory cytoki

  18. The complex interplay among bacterial motility and virulence factors in different Escherichia coli infections.

    Science.gov (United States)

    Kao, C Y; Lin, W H; Tseng, C C; Wu, A B; Wang, M C; Wu, J J

    2014-12-01

    Motility mediated by the flagella of Escherichia coli is important for the bacteria to move toward host cells. Here, we present the relationship among bacterial motility, virulence factors, antimicrobial susceptibility, and types of infection. A total of 231 clinical E. coli isolates from different infections were collected and analyzed. Higher-motility strains (motility diameter ≥6.6 mm) were more common in spontaneous bacterial peritonitis (SBP) (SBP 59 %, colonization 32 %, urinary tract infection 16 %, urosepsis 34 %, and biliary tract infection 29 %; p coli strains with lower motility. E. coli isolates with higher and lower motility were in different phylogenetic groups (p = 0.018), with a lower prevalence of A and B1 subgroups in higher-motility strains. Also, the patterns of virulence factors and antibiotic susceptibility of E. coli isolates derived from various infections were significantly different. This study demonstrates that the prevalence of higher-motility strains was greater in E. coli isolates from SBP compared to other types of infection. Various types of E. coli infection were associated with differences in bacterial motility, virulence factors, and antibiotic susceptibility. More bacterial virulence factors may be necessary for the development of extraintestinal infections caused by E. coli isolates with lower motility.

  19. Divergent composition of algal-bacterial biofilms developing under various external factors

    NARCIS (Netherlands)

    Barranguet, C.; Veuger, B.; van Beusekom, S.A.M.; Marvan, P.; Sinke, J.J.; Admiraal, W.

    2005-01-01

    The influence of external factors other than nutrients on biofilm development and composition was studied with a combination of optical (Confocal Laser Scanning Microscopy, PAM fluorometry) and chemical methods (EPS extraction, HPLC, TOC determination). The development of algal-bacterial biofilms wa

  20. Socioeconomic and behavioral factors leading to acquired bacterial resistance to antibiotics in developing countries.

    OpenAIRE

    Okeke, I. N.; Lamikanra, A; Edelman, R

    1999-01-01

    In developing countries, acquired bacterial resistance to antimicrobial agents is common in isolates from healthy persons and from persons with community-acquired infections. Complex socioeconomic and behavioral factors associated with antibiotic resistance, particularly regarding diarrheal and respiratory pathogens, in developing tropical countries, include misuse of antibiotics by health professionals, unskilled practitioners, and laypersons; poor drug quality; unhygienic conditions account...

  1. Sustainable control of pea bacterial blight : approaches for durable genetic resistance and biocontrol by endophytic bacteria

    NARCIS (Netherlands)

    Elvira-Recuenco, M.

    2000-01-01

    Key-words: bacterial blight, biological control, biodiversity, endophytic bacteria, L-form, pea, PDRl retrotransposon, Pisum sativum, Pisum abyssinicum, Pseudomonas syringae pv. pisi, race specific resistance, race non-specific resistance, Spanish

  2. Bacterial and fungal endophthalmitis in Upper Egypt: related species and risk factors

    OpenAIRE

    2012-01-01

    Objective: To study risk factors, contributing factors of bacterial and fungal endophthalmitis in Upper Egypt, test the isolated species sensitive to some therapeutic agents, and to investigate the air-borne bacteria and fungi in opthalmology operating rooms. Methods: Thirty one cases of endophthalmitis were clinically diagnosed and microbiologically studied. Indoor air-borne bacteria and fungi inside four air-conditioned operating rooms in the Ophthalmology Department at Assiut University...

  3. Factors influencing the composition of bacterial communities found at abandoned copper-tailings dumps.

    Science.gov (United States)

    De la Iglesia, R; Castro, D; Ginocchio, R; van der Lelie, D; González, B

    2006-03-01

    To study the effect that copper residues exert on bacterial communities and the ability of bacteria to colonize different microhabitats in abandoned tailing dumps. We used the terminal-restriction fragment length polymorphism technique, a culture-independent molecular approach based on PCR amplification of ribosomal genes, to compare the structure of the bacterial communities from samples taken at two nearby located abandoned tailing dumps found in the Mediterranean-climate area of central Chile. Our results show that elevated available copper content in tailings has a strong effect on the bacterial community composition, but that other factors like pH and organic matter content also play an important role in the structure of these communities. We also found that the number of abundant bacteria in these samples was significantly lower than in soils not exposed to metal pollution. In addition to bioavailable copper, bacterial communities found in copper-tailings dumps are also affected by several other environmental factors. This first report on environmental factors influencing microbial communities in copper-tailings dumps will help to devise appropriate restoration procedures in this type of polluted habitat.

  4. Bacterial infections after pediatric heart transplantation: Epidemiology, risk factors and outcomes.

    Science.gov (United States)

    Rostad, Christina A; Wehrheim, Karla; Kirklin, James K; Naftel, David; Pruitt, Elizabeth; Hoffman, Timothy M; L'Ecuyer, Thomas; Berkowitz, Katie; Mahle, William T; Scheel, Janet N

    2017-09-01

    Bacterial infections represent a major cause of morbidity and mortality in heart transplant recipients. However, data describing the epidemiology and outcomes of these infections in children are limited. We analyzed the Pediatric Heart Transplant Study database of patients transplanted between 1993 and 2014 to determine the etiologies, risk factors and outcomes of children with bacterial infections post-heart transplantation. Of 4,458 primary transplants in the database, there were 4,815 infections that required hospitalization or intravenous therapy, 2,047 (42.51%) of which were bacterial. The risk of bacterial infection was highest in the first month post-transplant, and the bloodstream was the most common site (24.82%). In the early post-transplant period (<30 days post-transplant), coagulase-negative staphylococci were the most common pathogens (16.97%), followed by Enterobacter sp (11.99%) and Pseudomonas sp (11.62%). In the late post-transplant period, community-acquired pathogens Streptococcus pneumoniae (6.27%) and Haemophilus influenzae (2.82%) were also commonly identified. Patients' characteristics independently associated with acquisition of bacterial infection included younger age (p < 0.0001) and ventilator (p < 0.0001) or extracorporeal membrane oxygenation (p = 0.03) use at time of transplant. Overall mortality post-bacterial infection was 33.78%, and previous cardiac surgery (p < 0.001) and multiple sites of infection (p = 0.004) were independent predictors of death. Bacteria were the most common causes of severe infections in pediatric heart transplant recipients and were associated with high mortality rates. The risk of acquiring a bacterial infection was highest in the first month post-transplant, and a large proportion of the infections were caused by multidrug-resistant pathogens. Copyright © 2017 International Society for the Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

  5. Heart Disease Risk Factors You Can Control

    Science.gov (United States)

    ... can control the following risk factors by making lifestyle changes. Your doctor might also suggest medicine to help control some risk factors, such as high blood pressure or high cholesterol. Poor blood cholesterol (koh-LESS-tur-ol) and triglyceride ( ...

  6. Can the Bacterial Community of a High Arctic Glacier Surface Escape Viral Control?

    Science.gov (United States)

    Rassner, Sara M. E.; Anesio, Alexandre M.; Girdwood, Susan E.; Hell, Katherina; Gokul, Jarishma K.; Whitworth, David E.; Edwards, Arwyn

    2016-01-01

    Glacial ice surfaces represent a seasonally evolving three-dimensional photic zone which accumulates microbial biomass and potentiates positive feedbacks in ice melt. Since viruses are abundant in glacial systems and may exert controls on supraglacial bacterial production, we examined whether changes in resource availability would promote changes in the bacterial community and the dynamics between viruses and bacteria of meltwater from the photic zone of a Svalbard glacier. Our results indicated that, under ambient nutrient conditions, low estimated viral decay rates account for a strong viral control of bacterial productivity, incurring a potent viral shunt of a third of bacterial carbon in the supraglacial microbial loop. Moreover, it appears that virus particles are very stable in supraglacial meltwater, raising the prospect that viruses liberated in melt are viable downstream. However, manipulating resource availability as dissolved organic carbon, nitrogen, and phosphorous in experimental microcosms demonstrates that the photic zone bacterial communities can escape viral control. This is evidenced by a marked decline in virus-to-bacterium ratio (VBR) concomitant with increased bacterial productivity and number. Pyrosequencing shows a few bacterial taxa, principally Janthinobacterium sp., dominate both the source meltwater and microcosm communities. Combined, our results suggest that viruses maintain high VBR to promote contact with low-density hosts, by the manufacture of robust particles, but that this necessitates a trade-off which limits viral production. Consequently, dominant bacterial taxa appear to access resources to evade viral control. We propose that a delicate interplay of bacterial and viral strategies affects biogeochemical cycling upon glaciers and, ultimately, downstream ecosystems. PMID:27446002

  7. Can the Bacterial Community of a High Arctic Glacier Surface Escape Viral Control?

    Science.gov (United States)

    Rassner, Sara M E; Anesio, Alexandre M; Girdwood, Susan E; Hell, Katherina; Gokul, Jarishma K; Whitworth, David E; Edwards, Arwyn

    2016-01-01

    Glacial ice surfaces represent a seasonally evolving three-dimensional photic zone which accumulates microbial biomass and potentiates positive feedbacks in ice melt. Since viruses are abundant in glacial systems and may exert controls on supraglacial bacterial production, we examined whether changes in resource availability would promote changes in the bacterial community and the dynamics between viruses and bacteria of meltwater from the photic zone of a Svalbard glacier. Our results indicated that, under ambient nutrient conditions, low estimated viral decay rates account for a strong viral control of bacterial productivity, incurring a potent viral shunt of a third of bacterial carbon in the supraglacial microbial loop. Moreover, it appears that virus particles are very stable in supraglacial meltwater, raising the prospect that viruses liberated in melt are viable downstream. However, manipulating resource availability as dissolved organic carbon, nitrogen, and phosphorous in experimental microcosms demonstrates that the photic zone bacterial communities can escape viral control. This is evidenced by a marked decline in virus-to-bacterium ratio (VBR) concomitant with increased bacterial productivity and number. Pyrosequencing shows a few bacterial taxa, principally Janthinobacterium sp., dominate both the source meltwater and microcosm communities. Combined, our results suggest that viruses maintain high VBR to promote contact with low-density hosts, by the manufacture of robust particles, but that this necessitates a trade-off which limits viral production. Consequently, dominant bacterial taxa appear to access resources to evade viral control. We propose that a delicate interplay of bacterial and viral strategies affects biogeochemical cycling upon glaciers and, ultimately, downstream ecosystems.

  8. Review: phage therapy: a modern tool to control bacterial infections.

    Science.gov (United States)

    Qadir, Muhammad Imran

    2015-01-01

    The evolution of antibiotic-resistant in bacteria has aggravated curiosity in development of alternative therapy to conventional drugs. One of the emerging drugs that can be used alternative to antibiotics is bacteriophage therapy. The use of living phages in the cure of lethal infectious life threatening diseases caused by Gram positive and Gram negative bacteria has been reported. Another development in the field of bacteriophage therapy is the use of genetically modified and non replicating phages in the treatment of bacterial infection. Genetically engineered bacteriophages can be used as adjuvant along with antibiotic therapy. Phages encoded with lysosomal enzymes are also effectual in the treatment of infectious diseases.

  9. HIV-Enhancing Factors Are Secreted by Reproductive Epithelia upon Inoculation with Bacterial Vaginosis-Associated Bacteria.

    Science.gov (United States)

    Eade, Colleen R; Diaz, Camila; Chen, Sixue; Cole, Amy L; Cole, Alexander M

    2015-01-01

    Bacterial vaginosis is a common reproductive infection in which commensal vaginal lactobacilli are displaced by a mixed population of pathogenic bacteria. Bacterial vaginosis increases susceptibility to HIV, and it has been suggested that host innate immune responses to pathogenic bacteria contribute to enhanced infection, yet the cellular mechanisms mediating the increased HIV susceptibility remain uncharacterized. We evaluated the HIV-enhancing effects of bacterial vaginosis by inoculating endocervical epithelia with Atopobium vaginae, a bacterial vaginosis-associated bacteria, and assaying secreted factors for HIV-enhancing activity. When epithelia and A. vaginae were cocultured, we observed increased HIV-enhancing activity mediated by secreted low molecular weight factors. From this complex mixture we identified several upregulated host proteins, which functioned in combination to enhance HIV infection. These studies suggest that the host immune response to bacterial vaginosis-associated bacteria results in the release of HIV-enhancing factors. The combined activity of bacterial vaginosis-induced proteins likely mediates HIV enhancement.

  10. Helicobacter pylori infection: An overview of bacterial virulence factors and pathogenesis

    Directory of Open Access Journals (Sweden)

    Cheng-Yen Kao

    2016-02-01

    Full Text Available Helicobacter pylori pathogenesis and disease outcomes are mediated by a complex interplay between bacterial virulence factors, host, and environmental factors. After H. pylori enters the host stomach, four steps are critical for bacteria to establish successful colonization, persistent infection, and disease pathogenesis: (1 Survival in the acidic stomach; (2 movement toward epithelium cells by flagella-mediated motility; (3 attachment to host cells by adhesins/receptors interaction; (4 causing tissue damage by toxin release. Over the past 20 years, the understanding of H. pylori pathogenesis has been improved by studies focusing on the host and bacterial factors through epidemiology researches and molecular mechanism investigations. These include studies identifying the roles of novel virulence factors and their association with different disease outcomes, especially the bacterial adhesins, cag pathogenicity island, and vacuolating cytotoxin. Recently, the development of large-scale screening methods, including proteomic, and transcriptomic tools, has been used to determine the complex gene regulatory networks in H. pylori. In addition, a more available complete genomic database of H. pylori strains isolated from patients with different gastrointestinal diseases worldwide is helpful to characterize this bacterium. This review highlights the key findings of H. pylori virulence factors reported over the past 20 years.

  11. Automatic Generation Control Using PI Controller with Bacterial Foraging for both Thermal and Hydro Plants

    Directory of Open Access Journals (Sweden)

    Preeti Hooda,

    2014-06-01

    Full Text Available The load-frequency control (LFC is used to restore the balance between load and generation in each control area by means of speed control. In power system, the main goal of load frequency control (LFC or automatic generation control (AGC is to maintain the frequency of each area and tie- line power flow within specified tolerance by adjusting the MW outputs of LFC generators so as to accommodate fluctuating load demands. In this paper, attempt is made to make a scheme for automatic generation control within a restructured environment considering effects of contracts between DISCOs and GENCOs to make power system network in normal state where, GENCO used are hydro plants as well as thermal plants. The bacterial foraging optimization technique is being developed, which is applied to AGC in an interconnected four area system.The performance of the system is obtained by MATLAB Simulink tool. The results are shown in frequency and power response for four area AGC system. In this paper we have shown practical work by using thermal and hydro both system at Genco’s side.As reheated system transfer function is being used.

  12. Factors affecting the bacterial community composition and heterotrophic production of Columbia River estuarine turbidity maxima.

    Science.gov (United States)

    Herfort, Lydie; Crump, Byron C; Fortunato, Caroline S; McCue, Lee Ann; Campbell, Victoria; Simon, Holly M; Baptista, António M; Zuber, Peter

    2017-08-06

    Estuarine turbidity maxima (ETM) function as hotspots of microbial activity and diversity in estuaries, yet, little is known about the temporal and spatial variability in ETM bacterial community composition. To determine which environmental factors affect ETM bacterial populations in the Columbia River estuary, we analyzed ETM bacterial community composition (Sanger sequencing and amplicon pyrosequencing of 16S rRNA gene) and bulk heterotrophic production ((3) H-leucine incorporation rates). We collected water 20 times to cover five ETM events and obtained 42 samples characterized by different salinities, turbidities, seasons, coastal regimes (upwelling vs. downwelling), locations, and particle size. Spring and summer populations were distinct. All May samples had similar bacterial community composition despite having different salinities (1-24 PSU), but summer non-ETM bacteria separated into marine, freshwater, and brackish assemblages. Summer ETM bacterial communities varied depending on coastal upwelling or downwelling conditions and on the sampling site location with respect to tidal intrusion during the previous neap tide. In contrast to ETM, whole (>0.2 μm) and free-living (0.2-3 μm) assemblages of non-ETM waters were similar to each other, indicating that particle-attached (>3 μm) non-ETM bacteria do not develop a distinct community. Brackish water type (ETM or non-ETM) is thus a major factor affecting particle-attached bacterial communities. Heterotrophic production was higher in particle-attached than free-living fractions in all brackish waters collected throughout the water column during the rise to decline of turbidity through an ETM event (i.e., ETM-impacted waters). However, free-living communities showed higher productivity prior to or after an ETM event (i.e., non-ETM-impacted waters). This study has thus found that Columbia River ETM bacterial communities vary based on seasons, salinity, sampling location, and particle size, with the

  13. Bacterial cell curvature through mechanical control of cell growth

    DEFF Research Database (Denmark)

    Cabeen, M.; Charbon, Godefroid; Vollmer, W.

    2009-01-01

    The cytoskeleton is a key regulator of cell morphogenesis. Crescentin, a bacterial intermediate filament-like protein, is required for the curved shape of Caulobacter crescentus and localizes to the inner cell curvature. Here, we show that crescentin forms a single filamentous structure...... that collapses into a helix when detached from the cell membrane, suggesting that it is normally maintained in a stretched configuration. Crescentin causes an elongation rate gradient around the circumference of the sidewall, creating a longitudinal cell length differential and hence curvature. Such curvature...... can be produced by physical force alone when cells are grown in circular microchambers. Production of crescentin in Escherichia coli is sufficient to generate cell curvature. Our data argue for a model in which physical strain borne by the crescentin structure anisotropically alters the kinetics...

  14. Enzymatic Reductive Dehalogenation Controls the Biosynthesis of Marine Bacterial Pyrroles.

    Science.gov (United States)

    El Gamal, Abrahim; Agarwal, Vinayak; Rahman, Imran; Moore, Bradley S

    2016-10-12

    Enzymes capable of performing dehalogenating reactions have attracted tremendous contemporary attention due to their potential application in the bioremediation of anthropogenic polyhalogenated persistent organic pollutants. Nature, in particular the marine environment, is also a prolific source of polyhalogenated organic natural products. The study of the biosynthesis of these natural products has furnished a diverse array of halogenation biocatalysts, but thus far no examples of dehalogenating enzymes have been reported from a secondary metabolic pathway. Here we show that the penultimate step in the biosynthesis of the highly brominated marine bacterial product pentabromopseudilin is catalyzed by an unusual debrominase Bmp8 that utilizes a redox thiol mechanism to remove the C-2 bromine atom of 2,3,4,5-tetrabromopyrrole to facilitate oxidative coupling to 2,4-dibromophenol. To the best of our knowledge, Bmp8 is first example of a dehalogenating enzyme from the established genetic and biochemical context of a natural product biosynthetic pathway.

  15. Factor XI-deficient mice display reduced inflammation, coagulopathy, and bacterial growth during listeriosis.

    Science.gov (United States)

    Luo, Deyan; Szaba, Frank M; Kummer, Lawrence W; Johnson, Lawrence L; Tucker, Erik I; Gruber, Andras; Gailani, David; Smiley, Stephen T

    2012-01-01

    In mice infected sublethally with Listeria monocytogenes, fibrin is deposited at low levels within hepatic tissue, where it functions protectively by limiting bacterial growth and suppressing hemorrhagic pathology. Here we demonstrate that mice infected with lethal doses of L. monocytogenes produce higher levels of fibrin and display evidence of systemic coagulopathy (i.e., thrombocytopenia, fibrinogen depletion, and elevated levels of thrombin-antithrombin complexes). When the hepatic bacterial burden exceeds 1×10(6) CFU, levels of hepatic fibrin correlate with the bacterial burden, which also correlates with levels of hepatic mRNA encoding the hemostatic enzyme factor XI (FXI). Gene-targeted FXI-deficient mice show significantly improved survival upon challenge with high doses of L. monocytogenes and also display reduced levels of hepatic fibrin, decreased evidence of coagulopathy, and diminished cytokine production (interleukin-6 [IL-6] and IL-10). While fibrin limits the bacterial burden during sublethal listeriosis in wild-type mice, FXI-deficient mice display a significantly improved capacity to restrain the bacterial burden during lethal listeriosis despite their reduced fibrin levels. They also show less evidence of hepatic necrosis. In conjunction with suboptimal antibiotic therapy, FXI-specific monoclonal antibody 14E11 improves survival when administered therapeutically to wild-type mice challenged with high doses of L. monocytogenes. Together, these findings demonstrate the utility of murine listeriosis as a model for dissecting qualitative differences between protective and pathological host responses and reveal novel roles for FXI in exacerbating inflammation and pathogen burden during a lethal bacterial infection.

  16. Factors related to occurrence and distribution of selected bacterial and protozoan pathogens in Pennsylvania streams

    Science.gov (United States)

    Duris, Joseph W.; Reif, Andrew G.; Donna A. Crouse,; Isaacs, Natasha M.

    2013-01-01

    The occurrence and distribution of fecal indicator bacteria (FIB) and bacterial and protozoan pathogens are controlled by diverse factors. To investigate these factors in Pennsylvania streams, 217 samples were collected quarterly from a 27-station water-quality monitoring network from July 2007 through August 2009. Samples were analyzed for concentrations of Escherichia coli (EC) and enterococci (ENT) indicator bacteria, concentrations of Cryptosporidium oocysts and Giardia cysts, and the presence of four genes related to pathogenic types of EC (eaeA, stx2, stx1, rfbO157) plus three microbial source tracking (MST) gene markers that are also associated with pathogenic ENT and EC (esp, LTIIa, STII). Water samples were concurrently analyzed for basic water chemistry, physical measures of water quality, nutrients, metals, and a suite of 79 organic compounds that included hormones, pharmaceuticals, and antibiotics. For each sample location, stream discharge was measured by using standardized methods at the time of sample collection, and ancillary sample site information, such as land use and geological characteristics, was compiled. Samples exceeding recreational water quality criteria were more likely to contain all measured pathogen genes but notCryptosporidium or Giardia (oo)cysts. FIB and Giardia density and frequency of eaeA gene occurrence were significantly related to season. When discharge at a sampling location was high (>75th percentile of daily mean discharge), there were greater densities of FIB and Giardia, and the stx2, rfbO157, STII, and esp genes were found more frequently than at other discharge conditions. Giardia occurrence was likely related to nonpoint sources, which are highly influential during seasonal overland transport resulting from snowmelt and elevated precipitation in late winter and spring in Pennsylvania. When MST markers of human, swine, or bovine origin were present, samples more frequently carried the eaeA, stx2

  17. Factors related to occurrence and distribution of selected bacterial and protozoan pathogens in Pennsylvania streams.

    Science.gov (United States)

    Duris, Joseph W; Reif, Andrew G; Krouse, Donna A; Isaacs, Natasha M

    2013-01-01

    The occurrence and distribution of fecal indicator bacteria (FIB) and bacterial and protozoan pathogens are controlled by diverse factors. To investigate these factors in Pennsylvania streams, 217 samples were collected quarterly from a 27-station water-quality monitoring network from July 2007 through August 2009. Samples were analyzed for concentrations of Escherichia coli (EC) and enterococci (ENT) indicator bacteria, concentrations of Cryptosporidium oocysts and Giardia cysts, and the presence of four genes related to pathogenic types of EC (eaeA, stx2, stx1, rfb(O157)) plus three microbial source tracking (MST) gene markers that are also associated with pathogenic ENT and EC (esp, LTIIa, STII). Water samples were concurrently analyzed for basic water chemistry, physical measures of water quality, nutrients, metals, and a suite of 79 organic compounds that included hormones, pharmaceuticals, and antibiotics. For each sample location, stream discharge was measured by using standardized methods at the time of sample collection, and ancillary sample site information, such as land use and geological characteristics, was compiled. Samples exceeding recreational water quality criteria were more likely to contain all measured pathogen genes but not Cryptosporidium or Giardia (oo)cysts. FIB and Giardia density and frequency of eaeA gene occurrence were significantly related to season. When discharge at a sampling location was high (>75th percentile of daily mean discharge), there were greater densities of FIB and Giardia, and the stx2, rfb(O157), STII, and esp genes were found more frequently than at other discharge conditions. Giardia occurrence was likely related to nonpoint sources, which are highly influential during seasonal overland transport resulting from snowmelt and elevated precipitation in late winter and spring in Pennsylvania. When MST markers of human, swine, or bovine origin were present, samples more frequently carried the eaeA, stx2, stx1, and rfb

  18. 细菌性阴道炎危险因素分析%Risk Factors for Bacterial Vaginitis

    Institute of Scientific and Technical Information of China (English)

    吴宏宇; 王敬华; 祁建青; 卢艳阳

    2011-01-01

    目的:分析细菌性阴道炎患病的相关因素,探讨其预防措施.方法:选择本院门诊检测细菌性阴道炎阳性患者180 例作为病例组,180 例细菌性阴道炎阴性者作为对照组,对其细菌性阴道炎相关因素进行分析,本研究相关危险因素包括:其他性传播疾病(衣原体感染史、淋病史、霉菌性阴道炎史及滴虫性阴道炎史)、避孕方式(避孕套、宫内节育器及安全期避孕)、相关行为因素(阴道清洁次数、方式,内裤消毒、洗澡地点及方式、性卫生习惯,流产次数).结果:单因素分析结果:淋病史、霉菌性阴道炎史、滴虫性阴道炎史、多次流产、及经常清洗阴道可增加细菌性阴道炎患病风险,选择避孕套避孕及良好的卫生习惯是细菌性阴道炎的保护因素;多因素Logistic 回归结果:滴虫性阴道炎史(OR=9.21) 、人流次数(OR=5.34) 、清洗阴道(OR=2.16) 可升高细菌性阴道炎患病风险,使用避孕套(OR=0.49) 、良好性卫生习惯(OR=0.53) 则具有保护作用.结论:避孕套避孕和良好的性卫生习惯可降低细菌性阴道炎的发病风险.%Objective: Analysis the risk factors of bacterial vaginitis and explore its preventive measures. Methods: Detection bacterial vzginosis-positive patients 180 cases as patient case group, 180 patients with bacterial vaginitis-negative as control group and bacterial vaginitis-related faceors were analyzed. In this study, risk factors include other sexually transmitted diseases, contraception and the behavioral factors. Results: Univariste analysia result: the history of ginirrhea, fungal vaginitis, trichomonas vaginitis, miscarriages times and vagina cleaning may increase the disease risk of bacterial vaginitis and the use of condom and the good sexual health habits may be a protective factor for bacterial vaginitis. Logistic regression results: Trichomonas vaginitis history(OR=9.12), flow times(OR=5.34)and cleaning the vagina(OR=2.16) may

  19. Prevalence of Small Intestinal Bacterial Overgrowth among Chronic Pancreatitis Patients: A Case-Control Study

    Directory of Open Access Journals (Sweden)

    Amelie Therrien

    2016-01-01

    Full Text Available Background. Patients with chronic pancreatitis (CP exhibit numerous risk factors for the development of small intestinal bacterial overgrowth (SIBO. Objective. To determine the prevalence of SIBO in patients with CP. Methods. Prospective, single-centre case-control study conducted between January and September 2013. Inclusion criteria were age 18 to 75 years and clinical and radiological diagnosis of CP. Exclusion criteria included history of gastric, pancreatic, or intestinal surgery or significant clinical gastroparesis. SIBO was detected using a standard lactulose breath test (LBT. A healthy control group also underwent LBT. Results. Thirty-one patients and 40 controls were included. The patient group was significantly older (53.8 versus 38.7 years; P < 0.01. The proportion of positive LBTs was significantly higher in CP patients (38.7 versus 2.5%: P < 0.01. A trend toward a higher proportion of positive LBTs in women compared with men was observed (66.6 versus 27.3%; P = 0.056. The subgroups with positive and negative LBTs were comparable in demographic and clinical characteristics, use of opiates, pancreatic enzymes replacement therapy (PERT, and severity of symptoms. Conclusion. The prevalence of SIBO detected using LBT was high among patients with CP. There was no association between clinical features and the risk for SIBO.

  20. Long-distance delivery of bacterial virulence factors by Pseudomonas aeruginosa outer membrane vesicles.

    Directory of Open Access Journals (Sweden)

    Jennifer M Bomberger

    2009-04-01

    Full Text Available Bacteria use a variety of secreted virulence factors to manipulate host cells, thereby causing significant morbidity and mortality. We report a mechanism for the long-distance delivery of multiple bacterial virulence factors, simultaneously and directly into the host cell cytoplasm, thus obviating the need for direct interaction of the pathogen with the host cell to cause cytotoxicity. We show that outer membrane-derived vesicles (OMV secreted by the opportunistic human pathogen Pseudomonas aeruginosa deliver multiple virulence factors, including beta-lactamase, alkaline phosphatase, hemolytic phospholipase C, and Cif, directly into the host cytoplasm via fusion of OMV with lipid rafts in the host plasma membrane. These virulence factors enter the cytoplasm of the host cell via N-WASP-mediated actin trafficking, where they rapidly distribute to specific subcellular locations to affect host cell biology. We propose that secreted virulence factors are not released individually as naked proteins into the surrounding milieu where they may randomly contact the surface of the host cell, but instead bacterial derived OMV deliver multiple virulence factors simultaneously and directly into the host cell cytoplasm in a coordinated manner.

  1. A window of opportunity to control the bacterial pathogen Pseudomonas aeruginosa combining antibiotics and phages.

    Science.gov (United States)

    Torres-Barceló, Clara; Arias-Sánchez, Flor I; Vasse, Marie; Ramsayer, Johan; Kaltz, Oliver; Hochberg, Michael E

    2014-01-01

    The evolution of antibiotic resistance in bacteria is a global concern and the use of bacteriophages alone or in combined therapies is attracting increasing attention as an alternative. Evolutionary theory predicts that the probability of bacterial resistance to both phages and antibiotics will be lower than to either separately, due for example to fitness costs or to trade-offs between phage resistance mechanisms and bacterial growth. In this study, we assess the population impacts of either individual or combined treatments of a bacteriophage and streptomycin on the nosocomial pathogen Pseudomonas aeruginosa. We show that combining phage and antibiotics substantially increases bacterial control compared to either separately, and that there is a specific time delay in antibiotic introduction independent of antibiotic dose, that minimizes both bacterial density and resistance to either antibiotics or phage. These results have implications for optimal combined therapeutic approaches.

  2. Bacterial and fungal endophthalmitis in Upper Egypt:related species and risk factors

    Institute of Scientific and Technical Information of China (English)

    AA Gharamah; AM Moharram; MA Ismail; AK AL-Hussaini

    2012-01-01

    Objective: To study risk factors, contributing factors of bacterial and fungal endophthalmitis in Upper Egypt, test the isolated species sensitive to some therapeutic agents, and to investigate the air-borne bacteria and fungi in opthalmology operating rooms. Methods: Thirty one cases of endophthalmitis were clinically diagnosed and microbiologically studied. Indoor air-borne bacteria and fungi inside four air-conditioned operating rooms in the Ophthalmology Department at Assiut University Hospitals were also investigated. The isolated microbes from endophthalmitis cases were tested for their ability to produce some extracellular enzymes including protease, lipase, urease, phosphatase and catalase. Also the ability of 5 fungal isolates from endophthalmitis origin to produce mycotoxins and their sensitivity to some therapeutic agents were studied. Results: Results showed that bacteria and fungi were responsihle for infection in 10 and 6 cases of endophthalmitis, respectively and only 2 cases produced a mixture of bacteria and fungi. Trauma was the most prevalent risk factor of endophthalmitis where 58.1% of the 31 cases were due to trauma. In ophthalmology operating rooms, different bacterial and fungal species were isolated. 8 bacterial and 5 fungal isolates showed their ability to produce enzymes while only 3 fungal isolates were able to produce mycotoxins. Terbinafine showed the highest effect against most isolates in vitro. Conclusions: The ability of bacterial and fungal isolates to produce extracellular enzymes and mycotoxins may be aid in the invasion and destruction of eye tissues. Microbial contamination of operating rooms with air-borne bacteria and fungi in the present work may be a source of postoperative endophthalmitis.

  3. Bacterial toxin-antitoxin gene system as containment control in yeast cells

    DEFF Research Database (Denmark)

    Kristoffersen, P.; Jensen, G. B.; Gerdes, K.;

    2000-01-01

    The potential of a bacterial toxin-antitoxin gene system for use in containment control in eukaryotes was explored. The Escherichia coli relE and relB genes were expressed in the yeast Saccharomyces cerevisiae, Expression of the relE gene was highly toxic to yeast cells. However, expression...... of the relB gene counteracted the effect of relE to some extent, suggesting that toxin-antitoxin interaction also occurs in S. cerevisiae, Thus, bacterial toxin-antitoxin gene systems also have potential applications in the control of cell proliferation in eukaryotic cells, especially in those industrial...

  4. Correlation models between environmental factors and bacterial resistance to antimony and copper.

    Directory of Open Access Journals (Sweden)

    Zunji Shi

    Full Text Available Antimony (Sb and copper (Cu are toxic heavy metals that are associated with a wide variety of minerals. Sb(III-oxidizing bacteria that convert the toxic Sb(III to the less toxic Sb(V are potentially useful for environmental Sb bioremediation. A total of 125 culturable Sb(III/Cu(II-resistant bacteria from 11 different types of mining soils were isolated. Four strains identified as Arthrobacter, Acinetobacter and Janibacter exhibited notably high minimum inhibitory concentrations (MICs for Sb(III (>10 mM,making them the most highly Sb(III-resistant bacteria to date. Thirty-six strains were able to oxidize Sb(III, including Pseudomonas-, Comamonas-, Acinetobacter-, Sphingopyxis-, Paracoccus- Aminobacter-, Arthrobacter-, Bacillus-, Janibacter- and Variovorax-like isolates. Canonical correspondence analysis (CCA revealed that the soil concentrations of Sb and Cu were the most obvious environmental factors affecting the culturable bacterial population structures. Stepwise linear regression was used to create two predictive models for the correlation between soil characteristics and the bacterial Sb(III or Cu(II resistance. The concentrations of Sb and Cu in the soil was the significant factors affecting the bacterial Sb(III resistance, whereas the concentrations of S and P in the soil greatly affected the bacterial Cu(II resistance. The two stepwise linear regression models that we derived are as follows: MIC(Sb(III=606.605+0.14533 x C(Sb+0.4128 x C(Cu and MIC((Cu(II=58.3844+0.02119 x C(S+0.00199 x CP [where the MIC(Sb(III and MIC(Cu(II represent the average bacterial MIC for the metal of each soil (μM, and the C(Sb, C(Cu, C(S and C(P represent concentrations for Sb, Cu, S and P (mg/kg in soil, respectively, p<0.01]. The stepwise linear regression models we developed suggest that metals as well as other soil physicochemical parameters can contribute to bacterial resistance to metals.

  5. Bacterial Vaginosis

    Science.gov (United States)

    ... Form Controls Cancel Submit Search the CDC Bacterial Vaginosis (BV) Note: Javascript is disabled or is not ... STD on Facebook Sexually Transmitted Diseases (STDs) Bacterial Vaginosis – CDC Fact Sheet Language: English (US) Españ ...

  6. Ribonucleases, antisense RNAs and the control of bacterial plasmids.

    Science.gov (United States)

    Saramago, Margarida; Bárria, Cátia; Arraiano, Cecília M; Domingues, Susana

    2015-03-01

    In the last decade regulatory RNAs have emerged as powerful tools to regulate the expression of genes both in prokaryotes and in eukaryotes. RNases, by degrading these RNA molecules, control the right amount of regulatory RNAs, which is fundamental for an accurate regulation of gene expression in the cell. Remarkably the first antisense RNAs identified were plasmid-encoded and their detailed study was crucial for the understanding of prokaryotic antisense RNAs. In this review we highlight the role of RNases in the precise modulation of antisense RNAs that control plasmid replication, maintenance and transfer.

  7. [The bacterial microflora of diabetic foot infection and factors determining its spectrum in Ouagadougou (Burkina Faso)].

    Science.gov (United States)

    Guira, O; Tiéno, H; Traoré, S; Diallo, I; Ouangré, E; Sagna, Y; Zabsonré, J; Yanogo, D; Traoré, S S; Drabo, Y J

    2015-12-01

    The aim of the study was to describe the bacterial microflora of diabetic foot infection and to identify the factors which determine the bacterial spectrum in order to increase empiric antibiotic prescription in Ouagadougou. The study was a cross-sectional one, carried from July 1st, 2011 to June 30, 2012 in the departments of internal medicine and general and digestive surgery in Yalgado Ouédraogo teaching hospital. Samples for bacteriological tests consisted of aspiration of pus through the healthy skin, curettage and swab of the base of the ulceration or tissue biopsy from foot lesions. The bacteria's sensitivity to antibiotics has been tested by the qualitative method (Kirby-Bauer). The frequency of diabetic foot infection was 14.45% and the monthly incidence 5.33. The mean age of patients was 56 years and the sex ratio 1.37. Foot ulcerations were chronic in 33 (51.56%), necrotic in 51 (79.69%) and associated with osteitis in 40 (62.5%) patients. Infection was grade 3 in 70.3% cases. Thirty-nine patients had received antibiotics before hospital admission. Among the 71 samples, 62 (87.32%) cultures were positive: 53 (85.48%) monomicrobial and 9 (14.52%) bimicrobial. Aerobic Gram-positive cocci (76%) were the most frequent from ulcerations: Staphylococcus aureus (32.39%), Streptococcus sp (18.30%). Negative coagulase staphylococci have been found in 23.94% cases. Aerobic gram-negative bacilli have been isolated from 24% ulcerations. No factor was associated with the type of bacteria. Gram-positive pathogen cocci showed a high sensitivity to amoxicillin-clavulanic acid and oxacillin. No methicillin-resistant Staphylococcus aureus (MRSA) or extended-spectrum beta lactamase Enterobacteriaceae (ESBL) have been isolated. A better design is necessary to a clarification of bacterial flora in diabetic foot infections. Prevention of bacterial resistance is also needed.

  8. Exploring the Influence of Environmental Factors on Bacterial Communities within the Rhizosphere of the Cu-tolerant plant, Elsholtzia splendens

    Science.gov (United States)

    Jiang, Longfei; Song, Mengke; Yang, Li; Zhang, Dayi; Sun, Yingtao; Shen, Zhenguo; Luo, Chunling; Zhang, Gan

    2016-10-01

    Bacterial communities of rhizospheric soils play an important role in the tolerance and uptake of metal-tolerant/hyperaccumulating plants to metals, e.g. the Cu-tolerant Elsholtzia splendens native to China. In this work, pyrosequencing of the bacterial 16S rRNA gene was firstly applied to investigate the rhizospheric bacterial community of E. splendens grown at Cu contaminated sites. The 47 phyla including 11 dominant phyla (>1%) in E. splendens rhizosphere were presented. The effects of Cu and other environmental factors (total organic carbon, total nitrogen and pH) on the rhizospheric bacterial community were studied comprehensively. The phyla abundances were affected by the environmental factors to different extent, and we found pH, instead of Cu concentration, influenced UniFrac distance significantly and was identified as the most important environmental factor affecting bacterial community. In addition, the influence of environmental factors on gene profiles was explored according to the predicted metagenomes obtained by PICRUSt (phylogenetic investigation of communities by reconstruction of unobserved states). Our study illustrates a view about Cu-tolerant E. splendens rhizospheric bacterial communities (composition, diversity and gene profiles) and their influencing factors, giving a hand for the understanding on bacterial community is formed and affected in rhizosphere.

  9. Integrated Control of Fire Blight with Bacterial Antagonists and Oxytetracycline

    Science.gov (United States)

    In the Pacific Northwest of the United States, the antibiotic streptomycin provided excellent control of fire blight until resistant isolates of Erwinia amylovora were prevalent. Oxytetracycline (Mycoshield) is now sprayed as an alternative antibiotic. We found that the duration of inhibitory acti...

  10. Bacteriophages for detection and control of bacterial pathogens in food and food-processing environment.

    Science.gov (United States)

    Brovko, Lubov Y; Anany, Hany; Griffiths, Mansel W

    2012-01-01

    This chapter presents recent advances in bacteriophage research and their application in the area of food safety. Section 1 describes general facts on phage biology that are relevant to their application for control and detection of bacterial pathogens in food and environmental samples. Section 2 summarizes the recently acquired data on application of bacteriophages to control growth of bacterial pathogens and spoilage organisms in food and food-processing environment. Section 3 deals with application of bacteriophages for detection and identification of bacterial pathogens. Advantages of bacteriophage-based methods are presented and their shortcomings are discussed. The chapter is intended for food scientist and food product developers, and people in food inspection and health agencies with the ultimate goal to attract their attention to the new developing technology that has a tremendous potential in providing means for producing wholesome and safe food.

  11. Recent trends in control methods for bacterial wilt diseases caused by Ralstonia solanacearum.

    Science.gov (United States)

    Yuliar; Nion, Yanetri Asi; Toyota, Koki

    2015-01-01

    Previous studies have described the development of control methods against bacterial wilt diseases caused by Ralstonia solanacearum. This review focused on recent advances in control measures, such as biological, physical, chemical, cultural, and integral measures, as well as biocontrol efficacy and suppression mechanisms. Biological control agents (BCAs) have been dominated by bacteria (90%) and fungi (10%). Avirulent strains of R. solanacearum, Pseudomonas spp., Bacillus spp., and Streptomyces spp. are well-known BCAs. New or uncommon BCAs have also been identified such as Acinetobacter sp., Burkholderia sp., and Paenibacillus sp. Inoculation methods for BCAs affect biocontrol efficacy, such as pouring or drenching soil, dipping of roots, and seed coatings. The amendment of different organic matter, such as plant residue, animal waste, and simple organic compounds, have frequently been reported to suppress bacterial wilt diseases. The combined application of BCAs and their substrates was shown to more effectively suppress bacterial wilt in the tomato. Suppression mechanisms are typically attributed to the antibacterial metabolites produced by BCAs or those present in natural products; however, the number of studies related to host resistance to the pathogen is increasing. Enhanced/modified soil microbial communities are also indirectly involved in disease suppression. New promising types of control measures include biological soil disinfection using substrates that release volatile compounds. This review described recent advances in different control measures. We focused on the importance of integrated pest management (IPM) for bacterial wilt diseases.

  12. Effects of granulocyte-colony stimulating factor on peritoneal defense mechanisms and bacterial translocation after administration of systemic chemotherapy in rats

    Institute of Scientific and Technical Information of China (English)

    Celal Cerci; Cagri Ergin; Erol Eroglu; Canan Agalar; Fatih Agalar; Sureyya Cerci; Mahmut Bulbul

    2007-01-01

    AIM: To investigate the effects of granulocyte-colony stimulating factor (G-CSF) on peritoneal defense mechanisms and bacterial translocation after systemic 5-Fluorouracil (5-FU) administration.METHODS: Thirty Wistar albino rats were divided into three groups; the control, 5-FU and 5-FU + G-CSF groups. We measured bactericidal activity of the peritoneal fluid, phagocytic activity of polymorphonuclear leucocytes in the peritoneal fluid, total peritoneal cell counts and cell types of peritoneal washing fluid.Bacterial translocation was quantified by mesenteric lymph node, liver and spleen tissue cultures.RESULTS: Systemic 5-FU reduced total peritoneal cell counts, neutrophils and macrophage numbers. It also altered bactericidal activity of the peritoneal fluid and phagocytic activity of polymorphonuclear leucocytes in the peritoneal fluid. 5-FU also caused significant increase in frequencies of bacterial translocation at the liver and mesenteric lymph nodes. G-CSF decreased bacterial translocation, it significantly enhanced bactericidal activity of the peritoneal fluid and phagocytic activity of polymorphonuclear leucocytes in the peritoneal fluid. It also increased total peritoneal cell counts, neutrophils and macrophage numbers.CONCLUSION: Systemic 5-FU administration caused bacterial translocation, decreased the bactericidal activity of peritoneal fluid and phagocytic activity of polymorphonuclear leucocytes in the peritoneal fluid. G-CSF increased both bactericidal activity of the peritoneal fluid and phagocytic activity of polymorphonuclear leucocytes in the peritoneal fluid, and prevented the bacterial translocation. We conclude that intraperitoneal GCSF administration protects the effects of systemic 5-FU on peritoneal defense mechanisms.

  13. Causal Factors in Genome Control

    NARCIS (Netherlands)

    O'Duibhir, E.

    2015-01-01

    The aim of this thesis is to study how genes are switched on and off in a coordinated way across an entire genome. In order to do this yeast is used as a model organism. The mechanisms that control gene expression in yeast are very similar to those of human cells. Chapter 1 provides a general introd

  14. Incidence and risk factors of bacterial vaginosis among pregnant women: a prospective study in Maanshan city, Anhui Province, China.

    Science.gov (United States)

    Li, Xiu-De; Tong, Fei; Zhang, Xiu-Jun; Pan, Wei-Jun; Chen, Mao-Lin; Wang, Cheng-Cheng; Li, Xiang; Gao, Guo-Peng; Sun, Liang; Sun, Ye-Huan

    2015-08-01

    The aim of this study was to identify the incidence and risk factors of bacterial vaginosis among pregnant women. Prospective data from a cohort of 668 pregnant women were used to identify potential risk factors for bacterial vaginosis during pregnancy by Cox proportional hazards regression. A total of 204 incident cases of bacterial vaginosis were diagnosed in 274.8 woman-years of follow-up. The bacterial vaginosis incidence rate was 0.74 per 1 woman-year and median prevalence during follow-up was 15.6%. In the adjusted model, changing underwear nearly everyday, miscarriage history, urinary tract infection during follow-up, husbands' education level, and concurrent trichomoniasis and candidiasis remained significantly associated with bacterial vaginosis (adjusted hazard ratio and 95% confidence interval were 1.87 [1.26-2.77]; 2.96 [1.96-4.47]; 2.41 [1.05-5.49]; 0.50 [0.32-0.77]; 1.82 [1.02-3.25]; 1.88 [1.30-2.70], respectively). Bacterial vaginosis during pregnancy can be affected by many factors, and some are indirectly acting factors. Further prospective studies that include a larger sample size and more information on the development of bacterial vaginosis are needed. © 2015 The Authors. Journal of Obstetrics and Gynaecology Research © 2015 Japan Society of Obstetrics and Gynecology.

  15. Role of the gut microbiota in host appetite control: bacterial growth to animal feeding behaviour.

    Science.gov (United States)

    Fetissov, Sergueï O

    2017-01-01

    The life of all animals is dominated by alternating feelings of hunger and satiety - the main involuntary motivations for feeding-related behaviour. Gut bacteria depend fully on their host for providing the nutrients necessary for their growth. The intrinsic ability of bacteria to regulate their growth and to maintain their population within the gut suggests that gut bacteria can interfere with molecular pathways controlling energy balance in the host. The current model of appetite control is based mainly on gut-brain signalling and the animal's own needs to maintain energy homeostasis; an alternative model might also involve bacteria-host communications. Several bacterial components and metabolites have been shown to stimulate intestinal satiety pathways; at the same time, their production depends on bacterial growth cycles. This short-term bacterial growth-linked modulation of intestinal satiety can be coupled with long-term regulation of appetite, controlled by the neuropeptidergic circuitry in the hypothalamus. Indeed, several bacterial products are detected in the systemic circulation, which might act directly on hypothalamic neurons. This Review analyses the data relevant to possible involvement of the gut bacteria in the regulation of host appetite and proposes an integrative homeostatic model of appetite control that includes energy needs of both the host and its gut bacteria.

  16. Gut microbiota promote hematopoiesis to control bacterial infection.

    Science.gov (United States)

    Khosravi, Arya; Yáñez, Alberto; Price, Jeremy G; Chow, Andrew; Merad, Miriam; Goodridge, Helen S; Mazmanian, Sarkis K

    2014-03-12

    The commensal microbiota impacts specific immune cell populations and their functions at peripheral sites, such as gut mucosal tissues. However, it remains unknown whether gut microbiota control immunity through regulation of hematopoiesis at primary immune sites. We reveal that germ-free mice display reduced proportions and differentiation potential of specific myeloid cell progenitors of both yolk sac and bone marrow origin. Homeostatic innate immune defects may lead to impaired early responses to pathogens. Indeed, following systemic infection with Listeria monocytogenes, germ-free and oral-antibiotic-treated mice display increased pathogen burden and acute death. Recolonization of germ-free mice with a complex microbiota restores defects in myelopoiesis and resistance to Listeria. These findings reveal that gut bacteria direct innate immune cell development via promoting hematopoiesis, contributing to our appreciation of the deep evolutionary connection between mammals and their microbiota.

  17. Influence of uranium on bacterial communities: a comparison of natural uranium-rich soils with controls.

    Directory of Open Access Journals (Sweden)

    Laure Mondani

    Full Text Available This study investigated the influence of uranium on the indigenous bacterial community structure in natural soils with high uranium content. Radioactive soil samples exhibiting 0.26% - 25.5% U in mass were analyzed and compared with nearby control soils containing trace uranium. EXAFS and XRD analyses of soils revealed the presence of U(VI and uranium-phosphate mineral phases, identified as sabugalite and meta-autunite. A comparative analysis of bacterial community fingerprints using denaturing gradient gel electrophoresis (DGGE revealed the presence of a complex population in both control and uranium-rich samples. However, bacterial communities inhabiting uraniferous soils exhibited specific fingerprints that were remarkably stable over time, in contrast to populations from nearby control samples. Representatives of Acidobacteria, Proteobacteria, and seven others phyla were detected in DGGE bands specific to uraniferous samples. In particular, sequences related to iron-reducing bacteria such as Geobacter and Geothrix were identified concomitantly with iron-oxidizing species such as Gallionella and Sideroxydans. All together, our results demonstrate that uranium exerts a permanent high pressure on soil bacterial communities and suggest the existence of a uranium redox cycle mediated by bacteria in the soil.

  18. Differential Control Efficacies of Vitamin Treatments against Bacterial Wilt and Grey Mould Diseases in Tomato Plants

    Science.gov (United States)

    Hong, Jeum Kyu; Kim, Hyeon Ji; Jung, Heesoo; Yang, Hye Ji; Kim, Do Hoon; Sung, Chang Hyun; Park, Chang-Jin; Chang, Seog Won

    2016-01-01

    Bacterial wilt and grey mould in tomato plants are economically destructive bacterial and fungal diseases caused by Ralstonia solanacearum and Botrytis cinerea, respectively. Various approaches including chemical and biological controls have been attempted to arrest the tomato diseases so far. In this study, in vitro growths of bacterial R. solanacearum and fungal B. cinerea were evaluated using four different vitamins including thiamine (vitamin B1), niacin (vitamin B3), pyridoxine (vitamin B6), and menadione (vitamin K3). In planta efficacies of the four vitamin treatments on tomato protection against both diseases were also demonstrated. All four vitamins showed different in vitro antibacterial activities against R. solanacearum in dose-dependent manners. However, treatment with 2 mM thiamine was only effective in reducing bacterial wilt of detached tomato leaves without phytotoxicity under lower disease pressure (106 colony-forming unit [cfu]/ml). Treatment with the vitamins also differentially reduced in vitro conidial germination and mycelial growth of B. cinerea. The four vitamins slightly reduced the conidial germination, and thiamine, pyridoxine and menadione inhibited the mycelial growth of B. cinerea. Menadione began to drastically suppress the conidial germination and mycelial growth by 5 and 0.5 mM, respectively. Grey mould symptoms on the inoculated tomato leaves were significantly reduced by pyridoxine and menadione pretreatments one day prior to the fungal challenge inoculation. These findings suggest that disease-specific vitamin treatment will be integrated for eco-friendly management of tomato bacterial wilt and grey mould. PMID:27721697

  19. Epidemiology and Risk Factors Associated with Developing Bacterial Meningitis among Children in Gaza Strip.

    Directory of Open Access Journals (Sweden)

    Abdel Moat Al Jarousha

    2014-09-01

    Full Text Available Bacterial meningitis is still the leading cause of high morbidity and mortality among the children. The present study was conducted to determine the epidemiology, clinical characteristics of bacterial meningitis and to evaluate the risk factors associated with developing the infection.This cross sectional study was conducted in three hospitals of Gaza strip -Palestine during the period 2009. All the children with clinical diagnosis of meningitis /meningoencephalitis admitted to these hospitals were included in the study. They were subjected to clinical examination as well as CSF bacteriological and serological investigations.During the period (2009, 1853 patients were admitted to the hospitals with suspect of meningitis by pediatricians, 73 (3.9% proved by culture to be acute bacterial meningitis, of these patients 62% were males and 38% were females. The common isolated pathogens were Neisseria meningitides (47.9%, Streptococcus pneumonia (15.1%, Haemophilus influenza (13.7%, E. coli (11.0%, Enterobacter spp. (6.8%, Citrobacter spp. (2.7%, Providencia spp. (1.4%, and Pseudomonas aeruginosa (1.4%. The common recorded symptoms were fever (78%, neck stiffness (47%, vomiting (37%, poor feeding (19%, and irritability (16%. Statistical analysis showed that there was statistical significance associated developing of infection with malnutrition (low hemoglobin level, high house crowdness and irritability (P-value <0.05. The ANOVA statistical analysis showed that S. pneumonia has an impact on developing low hemoglobin level and leukocytosis.N. meningitides is still dominant and needs vaccination. The risk factors should be taken into consideration in any future plan.

  20. Meteorological factors and ambient bacterial levels in a subtropical urban environment

    Science.gov (United States)

    Wu, Yi-Hua; Chan, Chang-Chuan; Chew, Ginger L.; Shih, Po-Wen; Lee, Chung-Te; Chao, H. Jasmine

    2012-11-01

    We conducted a study to investigate the characteristics and determinants of ambient bacteria in Taipei, Taiwan from August 2004 to March 2005. We monitored ambient culturable bacteria in Shin-Jhuang City, an urban area in the Taipei metropolitan areas, using duplicate Burkard Portable Air Samplers with R2A agar. The average concentration of total bacteria was 1,986 colony-forming units per cubic meter of air (CFU/m3) (median = 780 CFU/m3) over the study period, with the highest level in autumn. Most bacterial taxa had similar seasonal variation, with higher concentrations in autumn and winter. During the study period, Gram negative rods and cocci were predominant. Multivariate analyses indicated that wind speed and wind direction significantly influenced ambient bacterial distribution. Temperature and relative humidity were also important environmental factors positively associated with ambient bacterial concentrations. We observed statistically significant relationships between ambient bacteria and air pollutants, including sulfur dioxide (SO2), ozone, particulate matter (aerodynamic diameter ≤10 μm (PM10)), methane and total hydrocarbons. The concentrations of methane and total hydrocarbons during the previous day were positively associated with total bacteria and Gram negative rods, respectively. Ozone level on the previous day had a negative relationship with Gram negative cocci. SO2 level with a 3-day lag was positively correlated with concentrations of both total bacteria and Gram negative cocci. In the future, more longitudinal studies are needed to confirm the relationships and possible mechanisms between ambient bacteria and meteorological factors, as well as to evaluate the ecological and health impacts of ambient bacteria.

  1. Treatment of tympanic membrane perforation using bacterial cellulose: a randomized controlled trial.

    Science.gov (United States)

    Silveira, Fábio Coelho Alves; Pinto, Flávia Cristina Morone; Caldas Neto, Sílvio da Silva; Leal, Mariana de Carvalho; Cesário, Jéssica; Aguiar, José Lamartine de Andrade

    2016-01-01

    Promising treatments for tympanic membrane perforation closure have been studied. Therapies derived from tissue engineering probably eliminate the need for conventional surgery. Bacterial cellulose is presented as an alternative that is safe, biocompatible, and has low toxicity. To investigate the effect on healing of direct application of a bacterial cellulose graft on the tympanic membrane compared to the conventional approach with autologous fascia. Randomized controlled trial. Forty patients with tympanic membrane perforations secondary to chronic otitis media were included, and were randomly assigned to an experimental group (20), treated with a bacterial cellulose graft (BC) and control group (20), treated with autologous temporal fascia (fascia). We evaluated the surgical time, hospital stay, time of epithelialization and the rate of tympanic perforation closure. Hospital costs were compared. The statistical significance level accepted was established at p<0.05. The closure of perforations was similar in both groups. The average operation time in the fascia group was 76.50 min versus 14.06 min bacterial cellulose in the group (p=0.0001). The hospital cost by the Brazilian public health system was R$ 600.00 for the bacterial cellulose group, and R$ 7778.00 for the fascia group (p=0.0001). Bacterial cellulose grafts promoted the closure of the tympanic membrane perforations, and were demonstrated to be innovative, effective, safe, minimally invasive, efficacious and to have a very low cost. Copyright © 2015 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

  2. DMPD: Lipopolysaccharide sensing an important factor in the innate immune response toGram-negative bacterial infections: benefits and hazards of LPShypersensitivity. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available portant factor in the innate immune response toGram-negative bacterial infections: benefits and hazards of L...une response toGram-negative bacterial infections: benefits and hazards of LPShyp...18406367 Lipopolysaccharide sensing an important factor in the innate immune response toGram-negative bacter...ial infections: benefits and hazards of LPShypersensitivity. Freudenberg MA, Tchapt

  3. Soil factors exhibit greater influence than bacterial inoculation on alfalfa growth and nitrogen fixation.

    Science.gov (United States)

    Neumann, Ute; Kosier, Bob; Jahnke, Joachim; Priefer, Ursula B; Al-Halbouni, Djamila

    2011-09-01

    In order to study the effects of soil factors and bacterial inoculation on alfalfa (Medicago sativa), plants were inoculated with Ensifer meliloti L33 and Azospirillum brasilense Sp7 in pot experiments using two different soils separately as well as in a mixture. One soil was contaminated with chemical waste products; the other was an arable soil. Soil factors, including the availability of macro- and micronutrients as well as carbon and nitrogen contents, were found to exhibit a much greater influence on the growth of alfalfa than any of the inoculations. In contaminated soil, the shoot and root growth of alfalfa was decreased and nodules were diminished and ineffective. Bacterial inoculations did not significantly improve this hostile growth environment. However, in a mixture (44% arable, 22% contaminated soil, 34% vermiculite), growth conditions for alfalfa were improved so that shoot dry weight and nodule numbers increased up to 100- and 20-fold, respectively, compared with the contaminated soil. For the strain L33, its persistence in the rhizosphere was correlated to the presence of its host plant, but its dynamics were influenced by competition with indigenous rhizobia. The strain Sp7, once provided with a suitable soil, was not dependent on the plant's rhizosphere, but it enhanced the performance of L33 and native rhizobia.

  4. Elongation factor P mediates a novel post-transcriptional regulatory pathway critical for bacterial virulence

    DEFF Research Database (Denmark)

    Zou, S Betty; Roy, Hervé; Ibba, Michael;

    2012-01-01

    Bacterial pathogens detect and integrate multiple environmental signals to coordinate appropriate changes in gene expression including the selective expression of virulence factors, changes to metabolism and the activation of stress response systems. Mutations that abolish the ability of the path......Bacterial pathogens detect and integrate multiple environmental signals to coordinate appropriate changes in gene expression including the selective expression of virulence factors, changes to metabolism and the activation of stress response systems. Mutations that abolish the ability...... of the pathogen to respond to external cues are typically attenuating. Here we discuss our recent discovery of a novel post-transcriptional regulatory pathway critical for Salmonella virulence and stress resistance. The enzymes PoxA and YjeK coordinately attach a unique beta-amino acid onto a highly conserved...... our laboratory and others now suggests that EF-P, previously thought to be essential, instead plays an ancillary role in translation by regulating the synthesis of a relatively limited subset of proteins. Other observations suggest that the eukaryotic homolog of EF-P, eIF5A, may illicit similar...

  5. Bacterial genus is a risk factor for major amputation in patients with diabetic foot.

    Science.gov (United States)

    Cardoso, Natália Anício; Cisneiros, Lígia DE Loiola; Machado, Carla Jorge; Cenedezi, Juliana Merlin; Procópio, Ricardo Jayme; Navarro, Túlio Pinho

    2017-01-01

    to evaluate whether bacterial genus is a risk factor for major amputation in patients with diabetic foot and infected ulcer. we conducted a case-control, observational study of 189 patients with infected ulcers in diabetic feet admitted to the Vascular Surgery Service of the Risoleta Tolentino Neves Hospital, from January 2007 to December 2012. The bacteriological evaluation was performed in deep tissue cultures from the lesions and amputation was considered major when performed above the foot'smiddle tarsus. the patients'mean age was 61.9±12.7 years; 122 (64.6%) were men. The cultures were positive in 86.8%, being monomicrobial in 72% of the cases. In patients with major amputation, Acinetobacter spp. (24.4%), Morganella spp. (24.4%), Proteus spp. (23.1%) and Enterococcus spp. (19.2%) were the most frequent types of bacteria. The most commonly isolated species were Acinetobacter baumannii, Morganella morganii, Pseudomonas aeruginosa and Proteus mirabilis. As predictors of major amputation, we identified the isolation of the generaAcinetobacter spp. and Klebsiella spp., serum creatinine ≥1.3mg/dl and hemoglobin cultura de tecido profundo das lesões e a amputação foi considerada como maior quando realizada acima do médio tarso do pé. a média de idade dos pacientes foi 61,9±12,7 anos e 122 (64,6%) eram homens. As culturas foram positivas em 86,8%, sendo monomicrobianas em 72% dos casos. Nos pacientes com amputação maior, os gêneros de bactérias mais frequentes foram Acinetobacter spp. (24,4%), Morganella spp. (24,4%), Proteus spp. (23,1%) e Enterococcus spp. (19,2%) e as espécies mais isoladas foram Acinetobacter baumannii, Morganella morganii, Pseudomonas aeruginosa e Proteus mirabilis. Identificou-se como fatores preditivos para amputação maior o isolamento dos gêneros Acinetobacter spp. e Klebsiella spp.,e níveis séricos de creatinina ≥1,3mg/dl e de hemoglobina <11g/dl. os gêneros bacterianos Acinetobacter spp. e Klebsiella spp

  6. Multivalent nanofibers of a controlled length: regulation of bacterial cell agglutination.

    Science.gov (United States)

    Lee, Dong-Woo; Kim, Taehoon; Park, Il-Soo; Huang, Zhegang; Lee, Myongsoo

    2012-09-12

    Control of the size and shape of molecular assemblies on the nanometer scale in aqueous solutions is very important for the regulation of biological functions. Among the well-defined supramolecular structures of organic amphiphiles, one-dimensional nanofibers have attracted much attention because of their potential applications in biocompatible materials. Although much progress has been made in the field of self-assembled nanofibers, the ability to control the fiber length remains limited. The approach for control of the fiber length presented herein overcomes this limitation through the coassembly of amphiphilic rod-coil molecules in which the crystallinity of the aromatic segment can be regulated by π-π stacking interactions. The introduction of carbohydrate segments into the fiber exterior endows the nanofibers with the ability to adhere to bacterial cells. Notably, the fiber length systematically regulates the agglutination and proliferation of bacterial cells exposed to these fibers.

  7. Microenvironment and microbiology of skin wounds: the role of bacterial biofilms and related factors.

    Science.gov (United States)

    Scalise, A; Bianchi, A; Tartaglione, C; Bolletta, E; Pierangeli, M; Torresetti, M; Marazzi, M; Di Benedetto, G

    2015-01-01

    Wound healing is a systemic response to injury that impacts the entire body and not just the site of tissue damage; it represents one of the most complex biological processes. Our knowledge of wound healing continues to evolve and it is now clear that the wound microenvironment plays a crucial role. The interactions between cells and the surface microenvironment, referred to as the "biofilm," contributes to skin homeostasis and healing. Understanding the functional complexity of the wound microenvironment informs how various factors such as age, ischemia, or bacterial infections can impair or arrest the normal healing processes, and it also allows for the possibility of acting therapeutically on healing defects with microenvironment manipulation. Microbes represent a particularly important factor for influencing the wound microenvironment and therefore wound healing. Moreover, the role of infections, particularly those that are sustained by biofilm-forming bacteria, is mutually related to other microenvironment aspects, such as humidity, pH, metalloproteinases, and reactive oxygen species, on which the modern research of new therapeutic strategies is focused. Today, chronic wounds are a rapidly growing health care burden and it is progressively understood that many non-healing wounds might benefit from therapies that target microorganisms and their biofilm communities. There is no doubt that host factors like perfusion impairments, venous insufficiency, pressure issues, malnutrition, and comorbidities strongly impact the healing processes and therefore must be targeted in the therapeutic management, but this approach might be not enough. In this article, we detail how bacterial biofilms and related factors impair wound healing, the reasons they must be considered a treatment target that is as important as the host's local and systemic pathologic conditions, and the latest therapeutic strategies derived from the comprehension of the wound microenvironment. Copyright

  8. OK-432 reduces mortality and bacterial translocation in irradiated and granulocyte-colony stimulating factor (G-CSF)-treated mice

    Energy Technology Data Exchange (ETDEWEB)

    Nose, Masako; Uzawa, Akiko; Ogyu, Toshiaki [National Inst. of Radiological Sciences, Chiba (Japan); Suzuki, Gen

    2001-06-01

    Acute radiation induces bacterial translocation from the gut, followed by systemic infection and sepsis. In order to reduce the mortality after acute whole body irradiation, it is essential to control bacterial translocation. In this study, we established a bacterial translocation assay as a sensitive method to detect minor mucosal injury by radiation. By utilizing this assay, we evaluated the adverse effects, if any, of hematopoietic reagents on the mucosal integrity in the respiratory and gastro-intestinal tracts. Bacterial translocation to the liver and spleen occurred after whole-body irradiation if the dose exceeded 6 Gy. The administration of G-CSF unexpectedly increased the bacterial translocation in 8 Gy-irradiated mice. The pharmaceutical preparation of low-virulent Streptococcus pyogenes, OK-432, significantly reduced the endotoxin levels in peripheral blood without any reduction of bacterial translocation. A combined treatment with G-CSF and OK-432 decreased bacterial translocation and prevented death. This result indicates that the early administration of G-CSF has an adverse effect on bacterial translocation, and that a combined treatment of G-CSF and OK-432 attenuates the adverse effect of G-CSF and improves the survival rate after acute irradiation. (author)

  9. SigmoID: a user-friendly tool for improving bacterial genome annotation through analysis of transcription control signals

    Directory of Open Access Journals (Sweden)

    Yevgeny Nikolaichik

    2016-05-01

    Full Text Available The majority of bacterial genome annotations are currently automated and based on a ‘gene by gene’ approach. Regulatory signals and operon structures are rarely taken into account which often results in incomplete and even incorrect gene function assignments. Here we present SigmoID, a cross-platform (OS X, Linux and Windows open-source application aiming at simplifying the identification of transcription regulatory sites (promoters, transcription factor binding sites and terminators in bacterial genomes and providing assistance in correcting annotations in accordance with regulatory information. SigmoID combines a user-friendly graphical interface to well known command line tools with a genome browser for visualising regulatory elements in genomic context. Integrated access to online databases with regulatory information (RegPrecise and RegulonDB and web-based search engines speeds up genome analysis and simplifies correction of genome annotation. We demonstrate some features of SigmoID by constructing a series of regulatory protein binding site profiles for two groups of bacteria: Soft Rot Enterobacteriaceae (Pectobacterium and Dickeya spp. and Pseudomonas spp. Furthermore, we inferred over 900 transcription factor binding sites and alternative sigma factor promoters in the annotated genome of Pectobacterium atrosepticum. These regulatory signals control putative transcription units covering about 40% of the P. atrosepticum chromosome. Reviewing the annotation in cases where it didn’t fit with regulatory information allowed us to correct product and gene names for over 300 loci.

  10. SigmoID: a user-friendly tool for improving bacterial genome annotation through analysis of transcription control signals.

    Science.gov (United States)

    Nikolaichik, Yevgeny; Damienikan, Aliaksandr U

    2016-01-01

    The majority of bacterial genome annotations are currently automated and based on a 'gene by gene' approach. Regulatory signals and operon structures are rarely taken into account which often results in incomplete and even incorrect gene function assignments. Here we present SigmoID, a cross-platform (OS X, Linux and Windows) open-source application aiming at simplifying the identification of transcription regulatory sites (promoters, transcription factor binding sites and terminators) in bacterial genomes and providing assistance in correcting annotations in accordance with regulatory information. SigmoID combines a user-friendly graphical interface to well known command line tools with a genome browser for visualising regulatory elements in genomic context. Integrated access to online databases with regulatory information (RegPrecise and RegulonDB) and web-based search engines speeds up genome analysis and simplifies correction of genome annotation. We demonstrate some features of SigmoID by constructing a series of regulatory protein binding site profiles for two groups of bacteria: Soft Rot Enterobacteriaceae (Pectobacterium and Dickeya spp.) and Pseudomonas spp. Furthermore, we inferred over 900 transcription factor binding sites and alternative sigma factor promoters in the annotated genome of Pectobacterium atrosepticum. These regulatory signals control putative transcription units covering about 40% of the P. atrosepticum chromosome. Reviewing the annotation in cases where it didn't fit with regulatory information allowed us to correct product and gene names for over 300 loci.

  11. Temporal scaling of bacterial taxa is influenced by both stochastic and deterministic ecological factors.

    Science.gov (United States)

    van der Gast, Christopher J; Ager, Duane; Lilley, Andrew K

    2008-06-01

    Microorganisms operate at a range of spatial and temporal scales acting as key drivers of ecosystem properties. Therefore, many key questions in microbial ecology require the consideration of both spatial and temporal scales. Spatial scaling, in particular the species-area relationship (SAR), has a long history in ecology and has recently been addressed in microbial ecology. However, the temporal analogue of the SAR, the species-time relationship, has received far less attention even in the science of general ecology. Here we focus upon the role of temporal scaling in microbial ecological patterns by coupling molecular characterization of bacterial communities in discrete island (bioreactor) systems with a macroecological approach. Our findings showed that the temporal scaling exponent (slope), and therefore taxa turnover of the bacterial taxa-time relationship decreased as selective pressure (industrial wastewater concentration) increased. Also, as the concentration of industrial wastewater increased across the bioreactors, we observed a gradual switch from stochastic community assembly to more deterministic (niche)-based considerations. The identification of broad-scale statistical patterns is particularly relevant to microbial ecology, as it is frequently difficult to identify individual species or their functions. In this study, we identify wide-reaching statistical patterns of diversity and show that they are shaped by the prevalent underlying ecological factors.

  12. 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.

  13. Speed and Displacement Control System of Bearingless Brushless DC Motor Based on Improved Bacterial Foraging Algorithm

    Directory of Open Access Journals (Sweden)

    Diao Xiaoyan

    2016-01-01

    Full Text Available To solve the deficiencies of long optimization time and poor precision existing in conventional bacterial foraging algorithm (BFA in the process of parameter optimization, an improved bacterial foraging algorithm (IBFA is proposed and applied to speed and displacement control system of bearingless brushless DC (Bearingless BLDC motors. To begin with the fundamental principle of BFA, the proposed method is introduced and the individual intelligence is efficiently used in the process of parameter optimization, and then the working principle of bearingless BLDC motors is expounded. Finally, modeling and simulation of the speed and displacement control system of bearingless BLDC motors based on the IBFA are carried out by taking the software of MATLAB/Simulink as a platform. Simulation results show that, speed overshoot, torque ripple and rotor position oscillation are dramatically reduced, thus the proposed method has good application prospects in the field of bearingless motors.

  14. The transcription factor relish controls anaplasma marginale infection in the bovine tick rhipicephalus microplus

    Science.gov (United States)

    Rhipicephalus microplus is an important biological vector of Anaplasma marginale, the etiological agent of bovine anaplasmosis. The knowledge of tick immune responses to control bacterial infections remains limited. In this study, we demonstrate that transcription factor Relish from the Imd signalin...

  15. Risk Factors of Streptococcus suis Infection in Vietnam. A Case-Control Study

    NARCIS (Netherlands)

    Dang, T.N.H.; Thi, P.T.L.; Wolbers, M.; Quang, T.C.; van, M.H.N.; Vu, T.N.T.; Hoan, P.N.; Thi, H.C.T.; Xuan, S.D.; Song, D.T.; Thi, T.H.H.; Truong, H.; Campbell, J.; van, V.C.N.; Tran, C.N.; van, D.N.; Thi, H.N.; Spratt, B.G.; Tinh, H.T.; Farrar, J.; Schultsz, C.

    2011-01-01

    Background: Streptococcus suis infection, an emerging zoonosis, is an increasing public health problem across South East Asia and the most common cause of acute bacterial meningitis in adults in Vietnam. Little is known of the risk factors underlying the disease. Methods and Findings: A case-control

  16. Application of a microcomputer-based system to control and monitor bacterial growth.

    Science.gov (United States)

    Titus, J A; Luli, G W; Dekleva, M L; Strohl, W R

    1984-02-01

    A modular microcomputer-based system was developed to control and monitor various modes of bacterial growth. The control system was composed of an Apple II Plus microcomputer with 64-kilobyte random-access memory; a Cyborg ISAAC model 91A multichannel analog-to-digital and digital-to-analog converter; paired MRR-1 pH, pO(2), and foam control units; and in-house-designed relay, servo control, and turbidimetry systems. To demonstrate the flexibility of the system, we grew bacteria under various computer-controlled and monitored modes of growth, including batch, turbidostat, and chemostat systems. The Apple-ISAAC system was programmed in Labsoft BASIC (extended Applesoft) with an average control program using ca. 6 to 8 kilobytes of memory and up to 30 kilobytes for datum arrays. This modular microcomputer-based control system was easily coupled to laboratory scale fermentors for a variety of fermentations.

  17. Thyristor Controlled Reactor for Power Factor Improvement

    Directory of Open Access Journals (Sweden)

    Sheila Mahapatra

    2014-04-01

    Full Text Available Power factor improvement is the essence of any power sector for reliable operation. This paper provides Thyristor Controlled Reactor regulated by programmed microcontroller which aids in improving power factor and retaining it close to unity under various loading conditions. The implementation is done on 8051 microcontrollerwhich isprogrammed using Keil software. To determine time lag between current and voltage PSpice softwareis used and to display power factor according tothe variation in loadProteus software is used. Whenever a capacitive load is connected to the transmission linea shunt reactor is connected which injects lagging reactive VARs to the power system. As a result the power factor is improved. The results given in this paper provides suitable microcontroller based reactive power compensation and power factor improvement technique using a Thyristor Controlled Reactor module.

  18. Commercialization of the power factor controller

    Science.gov (United States)

    1981-01-01

    The purpose of the Motor Power Controller, also known as the Power Factor Controller, is to improve power factor and reduce power dissipation in induction motors operating below full load. These purposes were studied and tested in detail. The Motor Power Controller is capable of raising power factors from 0.2 to 0.8 and results in energy savings. It was found that many motors, in their present operating applications, are classified as unstable. The electronic nature of the controller vs. the electrical nature of the motor, compound this problem due to the differences in response time of the two devices. Many tests were successfully completed, the most indicating greater savings than anticipated. Also, there was an effect on efficiency which was not included in the calculations.

  19. A Hybrid Bacterial Foraging - PSO Algorithm Based Tuning of Optimal FOPI Speed Controller

    Directory of Open Access Journals (Sweden)

    Rajasekhar Anguluri

    2011-11-01

    Full Text Available Bacterial Foraging Optimization Algorithm (BFOA has recently emerged as a very powerful technique for real parameteroptimization. In order to overcome the delay in optimization and to further enhance the performance of BFO, this paper proposeda new hybrid algorithm combining the features of BFOA and Particle Swarm Optimization (PSO for tuning a Fractional orderspeed controller in a Permanent Magnet Synchronous Motor (PMSM Drive. Computer simulations illustrate the effectiveness of theproposed approach compared to that of basic versions of PSO and BFO.

  20. The effects of pneumoperitoneum and controlled ventilation on peritoneal lymphatic bacterial clearance: experimental results in rats

    Directory of Open Access Journals (Sweden)

    Armando Angelo Casaroli

    2011-01-01

    Full Text Available OBJECTIVE: To evaluate the effect of pneumoperitoneum, both alone and in combination with controlled ventilation, on peritoneal lymphatic bacterial clearance using a rat bacterial peritonitis model. METHOD: A total of 69 male Wistar rats were intraperitoneally inoculated with an Escherichia coli solution (109 colony-forming units (cfu/mL and divided into three groups of 23 animals each: A (control group, B (pneumoperitoneum under 5 mmHg of constant pressure, and C (endotracheal intubation, controlled ventilation, and pneumoperitoneum as in Group B. The animals were sacrificed after 30 min under these conditions, and blood, mediastinal ganglia, lungs, peritoneum, liver, and spleen cultures were performed. RESULTS: Statistical analyses comparing the number of cfu/sample in each of the cultures showed that no differences existed between the three groups. CONCLUSION: Based on our results, we concluded that pneumoperitoneum, either alone or in association with mechanical ventilation, did not modify the bacterial clearance through the diaphragmatic lymphatic system of the peritoneal cavity.

  1. FACTORS WHICH MODIFY THE EFFECT OF SODIUM AND POTASSIUM ON BACTERIAL CELL MEMBRANES.

    Science.gov (United States)

    HENNEMAN, D H; UMBREIT, W W

    1964-06-01

    Henneman, Dorothy H. (Rutgers, The State University, New Brunswick, N.J.), and W. W. Umbreit. Factors which modify the effect of sodium and potassium on bacterial cell membranes. J. Bacteriol. 87:1266-1273. 1964.-Suspensions of Escherichia coli B, when placed in 0.2 to 0.5 m solutions of NaCl, KCl, or LiCl, show an increased turbidity. With NaCl, this increased turbidity is stable with time; with KCl and LiCl, it is gradually lost. The stability to NaCl with time is due to substances removable from the cell by incubation in phosphate buffer; these materials exist in water washings from such phosphate-incubated cells.

  2. A Common Structural Motif in the Binding of Virulence Factors to Bacterial Secretion Chaperones

    Energy Technology Data Exchange (ETDEWEB)

    Lilic,M.; Vujanac, M.; Stebbins, C.

    2006-01-01

    Salmonella invasion protein A (SipA) is translocated into host cells by a type III secretion system (T3SS) and comprises two regions: one domain binds its cognate type III secretion chaperone, InvB, in the bacterium to facilitate translocation, while a second domain functions in the host cell, contributing to bacterial uptake by polymerizing actin. We present here the crystal structures of the SipA chaperone binding domain (CBD) alone and in complex with InvB. The SipA CBD is found to consist of a nonglobular polypeptide as well as a large globular domain, both of which are necessary for binding to InvB. We also identify a structural motif that may direct virulence factors to their cognate chaperones in a diverse range of pathogenic bacteria. Disruption of this structural motif leads to a destabilization of several chaperone-substrate complexes from different species, as well as an impairment of secretion in Salmonella.

  3. Autoregulation of a bacterial sigma factor explored by using segmental isotopic labeling and NMR.

    Science.gov (United States)

    Camarero, Julio A; Shekhtman, Alexander; Campbell, Elizabeth A; Chlenov, Mark; Gruber, Tanja M; Bryant, Donald A; Darst, Seth A; Cowburn, David; Muir, Tom W

    2002-06-25

    Bacterial sigma factors combine with the catalytic core RNA polymerase to direct the process of transcription initiation through sequence-specific interactions with the -10 and -35 elements of promoter DNA. In the absence of core RNA polymerase, the DNA-binding function of sigma is autoinhibited by its own N-terminal 90 amino acids (region 1.1), putatively by a direct interaction with conserved region 4.2, which binds the -35 promoter element. In the present work, this mechanism of autoinhibition was studied by using a combination of NMR spectroscopy and segmental isotopic labeling of a sigma70-like subunit from Thermotoga maritima. Our data argue strongly against a high-affinity interaction between these two domains. Instead we suggest that autoinhibition of DNA binding occurs through an indirect steric and/or electrostatic mechanism. More generally, the present work illustrates the power of segmental isotopic labeling for probing molecular interactions in large proteins by NMR.

  4. Small Intestinal Bacterial Overgrowth in Patients with Irritable Bowel Syndrome: Clinical Characteristics, Psychological Factors, and Peripheral Cytokines

    Directory of Open Access Journals (Sweden)

    Hua Chu

    2016-01-01

    Full Text Available Small intestinal bacterial overgrowth (SIBO has been implicated in the pathogenesis of irritable bowel syndrome (IBS. Psychosocial factors and low-grade colonic mucosal immune activation have been suggested to play important roles in the pathophysiology of IBS. In total, 94 patients with IBS and 13 healthy volunteers underwent a 10 g lactulose hydrogen breath test (HBT with concurrent Tc99m scintigraphy. All participants also completed a face-to-face questionnaire survey, including the Hospital Anxiety and Depression Scale, Life Event Stress (LES, and general information. Serum tumour necrosis factor-α, interleukin- (IL- 6, IL-8, and IL-10 levels were measured. The 89 enrolled patients with IBS and 13 healthy controls had no differences in baseline characteristics. The prevalence of SIBO in patients with IBS was higher than that in healthy controls (39% versus 8%, resp.; p=0.026. Patients with IBS had higher anxiety, depression, and LES scores, but anxiety, depression, and LES scores were similar between the SIBO-positive and SIBO-negative groups. Psychological disorders were not associated with SIBO in patients with IBS. The serum IL-10 level was significantly lower in SIBO-positive than SIBO-negative patients with IBS.

  5. Manageable risk factors associated with bacterial and coliform counts in unpasteurized bulk milk in Flemish dairy herds.

    Science.gov (United States)

    Piepers, S; Zrimšek, P; Passchyn, P; De Vliegher, S

    2014-01-01

    Associations between herd management practices and both bacterial counts (BC) and coliform counts (CC) from 254 and 242 dairy herds in Flanders (Belgium), respectively, were studied. Data were analyzed using multivariable, multilevel linear regression analysis, allowing variance components analyses. Both BC and CC fluctuated throughout the year, although the milk quality parameters followed an opposite pattern. Bacterial count values decreased with each increase of the cleaning frequency of the cubicles (once per week, once per day, twice per day, or more than twice per day) between January and March. Herds with a conventional milking parlor had substantially lower BC than herds where the cows were milked using an automatic milking system. Lower BC were observed when the milking parlor was equipped with an automatic cluster removal system, when premilking teat disinfection was applied, when the dry cows were supplemented with a mix of minerals and vitamins, and when the teats were prepared either first wet and dried or via an automatic milking system. Milking cows with a high-pipeline milking parlor setup or with an automatic milking system was associated with substantially higher CC values. Herds where prepartum heifers were often treated with antimicrobials before calving had a lower CC than farms where heifers were either not or only rarely treated. Most variation in BC and CC resided at the herd level rather than at the observation level, indicating that management is important in the control of both BC and CC. Still, only a small proportion of the total variance was explained by factors capturing information related to the milking, herd health, and dry cow management, which suggests that the bacteriological milk quality and, in particular, CC is primarily driven by other factors than the ones included in this study.

  6. New insights in the bacterial spore resistance to extreme terrestrial and extraterrestrial factors

    Science.gov (United States)

    Moeller, Ralf; Horneck, Gerda; Reitz, Guenther

    Based on their unique resistance to various space parameters, Bacillus endospores are one of the model systems used for astrobiological studies. The extremely high resistance of bacterial endospores to environmental stress factors has intrigued researchers since long time and many characteristic spore features, especially those involved in the protection of spore DNA, have already been uncovered. The disclosure of the complete genomic sequence of Bacillus subtilis 168, one of the often used astrobiological model system, and the rapid development of tran-scriptional microarray techniques have opened new opportunities of gaining further insights in the enigma of spore resistance. Spores of B. subtilis were exposed to various extreme ter-restrial and extraterrestrial stressors to reach a better understanding of the DNA protection and repair strategies, which them to cope with the induced DNA damage. Following physical stress factors of environmental importance -either on Earth or in space -were selected for this thesis: (i) mono-and polychromatic UV radiation, (ii) ionizing radiation, (iii) exposure to ultrahigh vacuum; and (iv) high shock pressures simulating meteorite impacts. To reach a most comprehensive understanding of spore resistance to those harsh terrestrial or simulated extraterrestrial conditions, a standardized experimental protocol of the preparation and ana-lyzing methods was established including the determination of the following spore responses: (i) survival, (ii) induced mutations, (iii) DNA damage, (iv) role of different repair pathways by use of a set of repair deficient mutants, and (v) transcriptional responses during spore germi-nation by use of genome-wide transcriptome analyses and confirmation by RT-PCR. From this comprehensive set of data on spore resistance to a variety of environmental stress parameters a model of a "built-in" transcriptional program of bacterial spores in response to DNA damaging treatments to ensure DNA restoration

  7. Environmental factors shaping the abundance and distribution of laccase-encoding bacterial community with potential phenolic oxidase capacity during composting.

    Science.gov (United States)

    Lu, Lunhui; Zeng, Guangming; Fan, Changzheng; Guo, Jinsong; Zhang, Jiachao; Chen, Ming; Wu, Haipeng; Yuan, Yujie; He, Xiaoxiao; He, Yan

    2015-11-01

    Increasing molecular evidence points to a wide occurrence of laccase-like multicopper oxidase (LMCO)-encoding genes in bacteria. Most researches mainly focused on the bacterial LMCO diversity, whereas the processes and the environmental factors responsible for structuring bacterial LMCO communities remain relatively unknown in a composting system. Six gene libraries were constructed from samples in representative stages during composting. A total of 185 sequences obtained from sample DNA extracts were classified to 59 operational taxonomic units (OTUs) based on 10 % cutoff. The distribution profile of bacterial LMCO genes showed that proteobacterial- and actinobacterial-associated species were the dominant communities during composting. Pearson correlation analysis indicated that the pile temperature and water-soluble carbon (WSC) content were significantly positively correlated with bacterial LMCO gene OTU numbers, Chao1 and Shannon index, whereas the humic acid (HA)-like carbon content had the most significant effect on the distribution of the bacterial LMCO genes during composting by redundancy analysis. These findings will improve the understanding of the mutual relationship between environmental factors and bacterial LMCO community compositions in composting.

  8. 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.

  9. Enhancement of Methacholine-Evoked Tracheal Contraction Induced by Bacterial Lipopolysaccharides Depends on Epithelium and Tumor Necrosis Factor

    Directory of Open Access Journals (Sweden)

    T. Secher

    2012-01-01

    Full Text Available Inhaled bacterial lipopolysaccharides (LPSs induce an acute tumour necrosis factor-alpha (TNF-α- dependent inflammatory response in the murine airways mediated by Toll-like receptor 4 (TLR4 via the myeloid differentiation MyD88 adaptor protein pathway. However, the contractile response of the bronchial smooth muscle and the role of endogenous TNFα in this process have been elusive. We determined the in vivo respiratory pattern of C57BL/6 mice after intranasal LPS administration with or without the presence of increasing doses of methacholine (MCh. We found that LPS administration altered the basal and MCh-evoked respiratory pattern that peaked at 90 min and decreased thereafter in the next 48 h, reaching basal levels 7 days later. We investigated in controlled ex vivo condition the isometric contraction of isolated tracheal rings in response to MCh cholinergic stimulation. We observed that preincubation of the tracheal rings with LPS for 90 min enhanced the subsequent MCh-induced contractile response (hyperreactivity, which was prevented by prior neutralization of TNFα with a specific antibody. Furthermore, hyperreactivity induced by LPS depended on an intact epithelium, whereas hyperreactivity induced by TNFα was well maintained in the absence of epithelium. Finally, the enhanced contractile response to MCh induced by LPS when compared with control mice was not observed in tracheal rings from TLR4- or TNF- or TNF-receptor-deficient mice. We conclude that bacterial endotoxin-mediated hyperreactivity of isolated tracheal rings to MCh depends upon TLR4 integrity that signals the activation of epithelium, which release endogenous TNFα.

  10. 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.

  11. Extravaginal reservoirs of vaginal bacteria as risk factors for incident bacterial vaginosis.

    Science.gov (United States)

    Marrazzo, Jeanne M; Fiedler, Tina L; Srinivasan, Sujatha; Thomas, Katherine K; Liu, Congzhou; Ko, Daisy; Xie, Hu; Saracino, Misty; Fredricks, David N

    2012-05-15

    Bacterial vaginosis (BV) represents shifts in microbiota from Lactobacillus spp. to diverse anaerobes. Although antibiotics relieve symptoms and temporarily eradicate BV-associated bacteria (BVAB), BV usually recurs. We investigated the role of extravaginal BVAB reservoirs in recurrence. Risks for BV acquisition over the course of 1 year were defined. DNA in vaginal, anal, and oral swab samples from enrollment was subjected to quantitative polymerase chain reaction assays targeting 16S ribosomal RNA genes of Gardnerella vaginalis, Lactobacillus crispatus, BVAB1, BVAB2, BVAB3, Megasphaera spp., Lactobacillus jensenii, and Leptotrichia/Sneathia spp. A case-control approach analyzed BVAB detection at enrollment for case patients (BV acquisition) versus controls (none). Of 239 women enrolled without BV, 199 were seen in follow-up, and 40 experienced BV; 15 had all samples for analysis. Detection of G. vaginalis in oral cavity or anal samples and Leptotrichia/Sneathia spp. in anal samples was more common at enrollment among case patients, who also had higher concentrations of these bacteria and Megasphaera relative to 30 controls at each site. In contrast, L. crispatus was detected more frequently in anal samples among controls. Women who acquire BV are more likely have previous colonization of extravaginal reservoirs with some BVAB, and less likely to have L. crispatus, suggesting that BVAB may be acquired vaginally from extravaginal reservoirs.

  12. Arabidopsis Clade I TGA Factors Regulate Apoplastic Defences against the Bacterial Pathogen Pseudomonas syringae through Endoplasmic Reticulum-Based Processes

    OpenAIRE

    Lipu Wang; Pierre R Fobert

    2013-01-01

    During the plant immune response, large-scale transcriptional reprogramming is modulated by numerous transcription (co) factors. The Arabidopsis basic leucine zipper transcription factors TGA1 and TGA4, which comprise the clade I TGA factors, have been shown to positively contribute to disease resistance against virulent strains of the bacterial pathogen Pseudomonas syringae . Despite physically interacting with the key immune regulator, NON-EXPRESSOR OF PATHOGENESIS-RELATED GENES 1 (NPR1), f...

  13. Exposure to bacterial products lipopolysaccharide and flagellin and hepatocellular carcinoma: a nested case-control study.

    Science.gov (United States)

    Fedirko, Veronika; Tran, Hao Quang; Gewirtz, Andrew T; Stepien, Magdalena; Trichopoulou, Antonia; Aleksandrova, Krasimira; Olsen, Anja; Tjønneland, Anne; Overvad, Kim; Carbonnel, Franck; Boutron-Ruault, Marie-Christine; Severi, Gianluca; Kühn, Tilman; Kaaks, Rudolf; Boeing, Heiner; Bamia, Christina; Lagiou, Pagona; Grioni, Sara; Panico, Salvatore; Palli, Domenico; Tumino, Rosario; Naccarati, Alessio; Peeters, Petra H; Bueno-de-Mesquita, H B; Weiderpass, Elisabete; Castaño, José María Huerta; Barricarte, Aurelio; Sánchez, María-José; Dorronsoro, Miren; Quirós, J Ramón; Agudo, Antonio; Sjöberg, Klas; Ohlsson, Bodil; Hemmingsson, Oskar; Werner, Mårten; Bradbury, Kathryn E; Khaw, Kay-Tee; Wareham, Nick; Tsilidis, Konstantinos K; Aune, Dagfinn; Scalbert, Augustin; Romieu, Isabelle; Riboli, Elio; Jenab, Mazda

    2017-04-04

    Leakage of bacterial products across the gut barrier may play a role in liver diseases which often precede the development of liver cancer. However, human studies, particularly from prospective settings, are lacking. We used a case-control study design nested within a large prospective cohort to assess the association between circulating levels of anti-lipopolysaccharide (LPS) and anti-flagellin immunoglobulin A (IgA) and G (IgG) (reflecting long-term exposures to LPS and flagellin, respectively) and risk of hepatocellular carcinoma. A total of 139 men and women diagnosed with hepatocellular carcinoma between 1992 and 2010 were matched to 139 control subjects. Multivariable rate ratios (RRs), including adjustment for potential confounders, hepatitis B/C positivity, and degree of liver dysfunction, were calculated with conditional logistic regression. Antibody response to LPS and flagellin was associated with a statistically significant increase in the risk of hepatocellular carcinoma (highest vs. lowest quartile: RR = 11.76, 95% confidence interval = 1.70-81.40; P trend = 0.021). This finding did not vary substantially by time from enrollment to diagnosis, and did not change after adjustment for chronic infection with hepatitis B and C viruses. These novel findings, based on exposures up to several years prior to diagnosis, support a role for gut-derived bacterial products in hepatocellular carcinoma development. Further study into the role of gut barrier failure and exposure to bacterial products in liver diseases is warranted.

  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. Role of Staphylococcus aureus Virulence Factors in Inducing Inflammation and Vascular Permeability in a Mouse Model of Bacterial Endophthalmitis.

    Directory of Open Access Journals (Sweden)

    Ajay Kumar

    Full Text Available Staphylococcus (S. aureus is a common causative agent of bacterial endophthalmitis, a vision threatening complication of eye surgeries. The relative contribution of S. aureus virulence factors in the pathogenesis of endophthalmitis remains unclear. Here, we comprehensively analyzed the development of intraocular inflammation, vascular permeability, and the loss of retinal function in C57BL/6 mouse eyes, challenged with live S. aureus, heat-killed S. aureus (HKSA, peptidoglycan (PGN, lipoteichoic acid (LTA, staphylococcal protein A (SPA, α-toxin, and Toxic-shock syndrome toxin 1 (TSST1. Our data showed a dose-dependent (range 0.01 μg/eye to 1.0 μg/eye increase in the levels of inflammatory mediators by all virulence factors. The cell wall components, particularly PGN and LTA, seem to induce higher levels of TNF-α, IL-6, KC, and MIP2, whereas the toxins induced IL-1β. Similarly, among the virulence factors, PGN induced higher PMN infiltration. The vascular permeability assay revealed significant leakage in eyes challenged with live SA (12-fold and HKSA (7.3-fold, in comparison to other virulence factors (~2-fold and controls. These changes coincided with retinal tissue damage, as evidenced by histological analysis. The electroretinogram (ERG analysis revealed a significant decline in retinal function in eyes inoculated with live SA, followed by HKSA, SPA, and α-toxin. Together, these findings demonstrate the differential innate responses of the retina to S. aureus virulence factors, which contribute to intraocular inflammation and retinal function loss in endophthalmitis.

  16. Cold Plasma Inactivation of Bacterial Biofilms and Reduction of Quorum Sensing Regulated Virulence Factors.

    Directory of Open Access Journals (Sweden)

    Dana Ziuzina

    Full Text Available The main objectives of this work were to investigate the effect of atmospheric cold plasma (ACP against a range of microbial biofilms commonly implicated in foodborne and healthcare associated human infections and against P. aeruginosa quorum sensing (QS-regulated virulence factors, such as pyocyanin, elastase (Las B and biofilm formation capacity post-ACP treatment. The effect of processing factors, namely treatment time and mode of plasma exposure on antimicrobial activity of ACP were also examined. Antibiofilm activity was assessed for E. coli, L. monocytogenes and S. aureus in terms of reduction of culturability and retention of metabolic activity using colony count and XTT assays, respectively. All samples were treated 'inpack' using sealed polypropylene containers with a high voltage dielectric barrier discharge ACP generated at 80 kV for 0, 60, 120 and 300 s and a post treatment storage time of 24 h. According to colony counts, ACP treatment for 60 s reduced populations of E. coli to undetectable levels, whereas 300 s was necessary to significantly reduce populations of L. monocytogenes and S. aureus biofilms. The results obtained from XTT assay indicated possible induction of viable but non culturable state of bacteria. With respect to P. aeruginosa QS-related virulence factors, the production of pyocyanin was significantly inhibited after short treatment times, but reduction of elastase was notable only after 300 s and no reduction in actual biofilm formation was achieved post-ACP treatment. Importantly, reduction of virulence factors was associated with reduction of the cytotoxic effects of the bacterial supernatant on CHO-K1 cells, regardless of mode and duration of treatment. The results of this study point to ACP technology as an effective strategy for inactivation of established biofilms and may play an important role in attenuation of virulence of pathogenic bacteria. Further investigation is warranted to propose direct evidence

  17. Anaerobes and Bacterial Vaginosis in Pregnancy: Virulence Factors Contributing to Vaginal Colonisation

    Science.gov (United States)

    Africa, Charlene W. J.; Nel, Janske; Stemmet, Megan

    2014-01-01

    The aetiology and pathogenesis of bacterial vaginosis (BV) is unclear but it appears to be associated with factors that disrupt the normal acidity of the vagina thus altering the equilibrium between the normal vaginal microbiota. BV has serious implications for female morbidity, including reports of pelvic inflammatory disease, adverse pregnancy outcomes, increased susceptibility to sexually transmitted infections and infertility. This paper reviewed new available information regarding possible factors contributing to the establishment of the BV vaginal biofilm, examined the proposed role of anaerobic microbial species recently detected by new culture-independent methods and discusses developments related to the effects of BV on human pregnancy. The literature search included Pubmed (NLM), LISTA (EBSCO), and Web of Science. Because of the complexity and diversity of population groups, diagnosis and methodology used, no meta-analysis was performed. Several anaerobic microbial species previously missed in the laboratory diagnosis of BV have been revealed while taking cognisance of newly proposed theories of infection, thereby improving our understanding and knowledge of the complex aetiology and pathogenesis of BV and its perceived role in adverse pregnancy outcomes. PMID:25014248

  18. Anaerobes and Bacterial Vaginosis in Pregnancy: Virulence Factors Contributing to Vaginal Colonisation

    Directory of Open Access Journals (Sweden)

    Charlene W. J. Africa

    2014-07-01

    Full Text Available The aetiology and pathogenesis of bacterial vaginosis (BV is unclear but it appears to be associated with factors that disrupt the normal acidity of the vagina thus altering the equilibrium between the normal vaginal microbiota. BV has serious implications for female morbidity, including reports of pelvic inflammatory disease, adverse pregnancy outcomes, increased susceptibility to sexually transmitted infections and infertility. This paper reviewed new available information regarding possible factors contributing to the establishment of the BV vaginal biofilm, examined the proposed role of anaerobic microbial species recently detected by new culture-independent methods and discusses developments related to the effects of BV on human pregnancy. The literature search included Pubmed (NLM, LISTA (EBSCO, and Web of Science. Because of the complexity and diversity of population groups, diagnosis and methodology used, no meta-analysis was performed. Several anaerobic microbial species previously missed in the laboratory diagnosis of BV have been revealed while taking cognisance of newly proposed theories of infection, thereby improving our understanding and knowledge of the complex aetiology and pathogenesis of BV and its perceived role in adverse pregnancy outcomes.

  19. Bacterial Etiology and Risk Factors Associated with Cellulitis and Purulent Skin Abscesses in Military Trainees

    Science.gov (United States)

    Johnson, Ryan C.; Ellis, Michael W.; Schlett, Carey D.; Millar, Eugene V.; LaBreck, Patrick T.; Mor, Deepika; Elassal, Emad M.; Lanier, Jeffrey B.; Redden, Cassie L.; Cui, Tianyuan; Teneza-Mora, Nimfa; Bishop, Danett K.; Hall, Eric R.; Bishop-Lilly, Kimberly A.

    2016-01-01

    Military trainees are at high risk for skin and soft-tissue infections (SSTIs). Although Staphylococcus aureus is associated with purulent SSTI, it is unclear to what degree this pathogen causes nonpurulent cellulitis. To inform effective prevention strategies and to provide novel insights into SSTI pathogenesis, we aimed to determine the etiology of SSTI in this population. We conducted a prospective observational study in US Army Infantry trainees with SSTI (cutaneous abscesses and cellulitis) from July 2012 through December 2014. We used standard microbiology, serology, and high-throughput sequencing to determine the etiology of SSTI. Furthermore, we compared purported risk factors as well as anatomic site colonization for S. aureus. Among 201 SSTI cases evaluated for SSTI risk factors, cellulitis was associated with lower extremity blisters (P = 0.01) and abscess was associated with methicillin-resistant S. aureus (MRSA) colonization (Pmicrobiome analysis, only 1 leading edge aspirate was culturable (Coagulase-negative Staphylococcus). Microbiome evaluation of aspirate specimens demonstrated that Rhodanobacter terrae was the most abundant species (66.8% average abundance), while abscesses were dominated by S. aureus (92.9% average abundance). Although abscesses and cellulitis share the spectrum of clinical SSTI, the bacterial etiologies as determined by current technology appear distinct. Furthermore, the presence of atypical bacteria within cellulitis aspirates may indicate novel mechanisms of cellulitis pathogenesis. Clinical Trials Registration: NCT01105767. PMID:27780238

  20. Altered Colonic Bacterial Fermentation as a Potential Pathophysiological Factor in Irritable Bowel Syndrome.

    Science.gov (United States)

    Ringel-Kulka, Tamar; Choi, Chang Hwan; Temas, Daniel; Kim, Ari; Maier, Daniele M; Scott, Karen; Galanko, Joseph A; Ringel, Yehuda

    2015-09-01

    Dysbiosis leading to abnormal intestinal fermentation has been suggested as a possible etiological mechanism in irritable bowel syndrome (IBS). We aimed to investigate the location and magnitude of altered intestinal bacterial fermentation in IBS and its clinical subtypes. IBS patients who satisfied the Rome III criteria (114) and 33 healthy controls (HC) were investigated. Intestinal fermentation was assessed using two surrogate measures: intestinal intraluminal pH and fecal short-chain fatty acids (SCFAs). Intraluminal pH and intestinal transit times were measured in the small and large bowel using a wireless motility capsule (SmartPill) in 47 IBS and 10 HC. Fecal SCFAs including acetate, propionate, butyrate, and lactate were analyzed by capillary gas chromatography in all enrolled subjects. Correlations between intestinal pH, fecal SCFAs, intestinal transit time, and IBS symptom scores were analyzed. Colonic intraluminal pH levels were significantly lower in IBS patients compared with HC (total colonic pH, 6.8 for IBS vs. 7.3 for HC, P=0.042). There were no differences in total and segmental pH levels in the small bowel between IBS patients and HC (6.8 vs. 6.8, P=not significant). The intraluminal colonic pH differences were consistent in all IBS subtypes. Total SCFA level was significantly lower in C-IBS patients than in D-IBS and M-IBS patients and HC. The total SCFA level in all IBS subjects was similar with that of HC. Colonic pH levels correlated positively with colon transit time (CTT) and IBS symptoms severity. Total fecal SCFAs levels correlated negatively with CTT and positively with stool frequency. Colonic intraluminal pH is decreased, suggesting higher colonic fermentation, in IBS patients compared with HC. Fecal SCFAs are not a sensitive marker to estimate intraluminal bacterial fermentation.

  1. Bacterial profiles of saliva in relation to diet, lifestyle factors, and socioeconomic status

    Directory of Open Access Journals (Sweden)

    Daniel Belstrøm

    2014-04-01

    Full Text Available Background and objective: The bacterial profile of saliva is composed of bacteria from different oral surfaces. The objective of this study was to determine whether different diet intake, lifestyle, or socioeconomic status is associated with characteristic bacterial saliva profiles. Design: Stimulated saliva samples from 292 participants with low levels of dental caries and periodontitis, enrolled in the Danish Health Examination Survey (DANHES, were analyzed for the presence of approximately 300 bacterial species by means of the Human Oral Microbe Identification Microarray (HOMIM. Using presence and levels (mean HOMIM-value of bacterial probes as endpoints, the influence of diet intake, lifestyle, and socioeconomic status on the bacterial saliva profile was analyzed by Mann–Whitney tests with Benjamini–Hochberg's correction for multiple comparisons and principal component analysis. Results: Targets for 131 different probes were identified in 292 samples, with Streptococcus and Veillonella being the most predominant genera identified. Two bacterial taxa (Streptococcus sobrinus and Eubacterium [11][G-3] brachy were more associated with smokers than non-smokers (adjusted p-value<0.01. Stratification of the group based on extreme ends of the parameters age, gender, alcohol consumption, body mass index (BMI, and diet intake had no statistical influence on the composition of the bacterial profile of saliva. Conversely, differences in socioeconomic status were reflected by the bacterial profiles of saliva. Conclusions: The bacterial profile of saliva seems independent of diet intake, but influenced by smoking and maybe socioeconomic status.

  2. Identification of host cytosolic sensors and bacterial factors regulating the type I interferon response to Legionella pneumophila.

    Directory of Open Access Journals (Sweden)

    Kathryn M Monroe

    2009-11-01

    Full Text Available Legionella pneumophila is a gram-negative bacterial pathogen that replicates in host macrophages and causes a severe pneumonia called Legionnaires' Disease. The innate immune response to L. pneumophila remains poorly understood. Here we focused on identifying host and bacterial factors involved in the production of type I interferons (IFN in response to L. pneumophila. It was previously suggested that the delivery of L. pneumophila DNA to the host cell cytosol is the primary signal that induces the type I IFN response. However, our data are not easily reconciled with this model. We provide genetic evidence that two RNA-sensing proteins, RIG-I and MDA5, participate in the IFN response to L. pneumophila. Importantly, these sensors do not seem to be required for the IFN response to L. pneumophila DNA, whereas we found that RIG-I was required for the response to L. pneumophila RNA. Thus, we hypothesize that bacterial RNA, or perhaps an induced host RNA, is the primary stimulus inducing the IFN response to L. pneumophila. Our study also identified a secreted effector protein, SdhA, as a key suppressor of the IFN response to L. pneumophila. Although viral suppressors of cytosolic RNA-sensing pathways have been previously identified, analogous bacterial factors have not been described. Thus, our results provide new insights into the molecular mechanisms by which an intracellular bacterial pathogen activates and also represses innate immune responses.

  3. Bacterial blight (Pseudomonas pisi Sackett) of peas in South Africa, with special reference to frost as a predisposing factor

    NARCIS (Netherlands)

    Boelema, B.H.

    1972-01-01

    In the beginning of the nineteen fifties bacterial blight caused much damage to pea crops in South Africa, particularly to those grown for seed production. A study has been made of the causal organism and the conditioning factors of the disease, special attention being paid to frost as a predisposin

  4. Risk Factors and Clinical Outcomes of Bacterial and Fungal Scleritis at a Tertiary Eye Care Hospital

    Science.gov (United States)

    Reddy, Jagadesh C.; Murthy, Somasheila I.; Reddy, Ashok K.; Garg, Prashant

    2015-01-01

    Purpose: The aim was to analyze demographics, risk factors, pathogenic organisms, and clinical outcome in cases with microbiologically proven bacterial or fungal scleritis. Materials and Methods: Retrospective review of all the medical records of patients with microbiologically proven infectious scleritis examined from March 2005 to December 2009 in the cornea services of L. V. Prasad Eye Institute, Hyderabad, India was done. Results: Forty-two eyes of 42 patients were included in this study. The mean age at presentation was 48.52 ± 14.10 years (range: 12-70). Surgery was the major risk factor seen in 24 eyes (58.5%). Scleral infection was noted after vitreoretinal surgery (with scleral buckle) in 15 eyes, cataract surgery in 3 eyes, pterygium surgery in 3 eyes, corneoscleral tear repair and scleral buckle surgery in 3 eyes. Sixteen eyes (39%) were on systemic or topical steroids at the time of presentation. History of injury was noted in 9 eyes (22%) and diabetes mellitus in 7 patients (17%). Associated keratitis was noted in 9 eyes (21.4%). The scleral abscess was unifocal in 33 eyes (78.5%), multifocal in 6 eyes (14.2%) and diffuse in 3 eyes (7.14%). The final follow-up ranged from 24 days to 37 months. The final visual acuity was better in 18 eyes (42.8%), stable in 13 (30.9%), and deteriorated in 7 eyes (16.6%). Recurrence was seen in 4 eyes (9.5%). Conclusions: Surgery is a major risk factor for infectious scleritis in our series. Fungus was the most common organism isolated. Thorough debridement and intensive use of medications have improved the outcome. PMID:25949079

  5. Bacterial colonisation in patients with bronchiectasis: microbiological pattern and risk factors

    Science.gov (United States)

    Angrill, J; Agusti, C; de Celis, R; Rano, A; Gonzalez, J; Sole, T; Xaubet, A; Rodriguez-Roisin, R; Torres, A

    2002-01-01

    Background: A study was undertaken to investigate the incidence, diagnostic yield of non-invasive and bronchoscopic techniques, and risk factors of airway colonisation in patients with bronchiectasis in a stable clinical situation. Methods: A 2 year prospective study of 77 patients with bronchiectasis in a stable clinical condition was performed in an 800 bed tertiary university hospital. The interventions used were pharyngeal swabs, sputum cultures and quantitative protected specimen brush (PSB) bacterial cultures (cut off point ≥102 cfu/ml) and bronchoalveolar lavage (BAL) (cut off point ≥103 cfu/ml). Results: The incidence of bronchial colonisation with potential pathogenic microorganisms (PPMs) was 64%. The most frequent PPMs isolated were Haemophilus influenzae (55%) and Pseudomonas spp (26%). Resistance to antibiotics was found in 30% of the isolated pathogens. When the sample was appropriate, the operative characteristics of the sputum cultures were similar to those obtained with the PSB taken as a gold standard. Risk factors associated with bronchial colonisation by PPMs in the multivariate analysis were: (1) diagnosis of bronchiectasis before the age of 14 years (odds ratio (OR)=3.92, 95% CI 1.29 to 11.95), (2) forced expiratory volume in 1 second (FEV1) <80% predicted (OR=3.91, 95% CI 1.30 to 11.78), and (3) presence of varicose or cystic bronchiectasis (OR=4.80, 95% CI 1.11 to 21.46). Conclusions: Clinically stable patients with bronchiectasis have a high prevalence of bronchial colonisation by PPMs. Sputum culture is a good alternative to bronchoscopic procedures for evaluation of this colonisation. Early diagnosis of bronchiectasis, presence of varicose-cystic bronchiectasis, and FEV1 <80% predicted appear to be risk factors for bronchial colonisation with PPMs. PMID:11809984

  6. Spatial Distribution of Bacterial Communities Driven by Multiple Environmental Factors in a Beach Wetland of the Largest Freshwater Lake in China

    Directory of Open Access Journals (Sweden)

    Xia eDing

    2015-02-01

    Full Text Available The spatial distributions of bacterial communities may be driven by multiple environmental factors. Thus, understanding the relationships between bacterial distribution and environmental factors is critical for understanding wetland stability and the functioning of freshwater lakes. However, little research on the bacterial communities in deep sediment layers exists. In this study, thirty clone libraries of 16S rRNA were constructed from a beach wetland of the Poyang Lake along both horizontal (distance to the water-land junction and vertical (sediment depth gradients to assess the effects of sediment properties on bacterial community structure and diversity. Our results showed that bacterial diversity increased along the horizontal gradient and decreased along the vertical gradient. The heterogeneous sediment properties along gradients substantially affected the dominant bacterial groups at the phylum and species levels. For example, the NH4+ concentration decreased with increasing depth, which was positively correlated with the relative abundance of Alphaproteobacteria. The changes in bacterial diversity and dominant bacterial groups showed that the top layer had a different bacterial community structure than the deeper layers. Principal component analysis revealed that both gradients, not each gradient independently, contributed to the shift in the bacterial community structure. A multiple linear regression model explained the changes in bacterial diversity and richness along the depth and distance gradients. Overall, our results suggest that spatial gradients associated with sediment properties shaped the bacterial communities in the Poyang Lake beach wetland.

  7. Bacterial Community Succession During in situ Uranium Bioremediation: Spatial Similarities Along Controlled Flow Paths

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Chiachi; Wu, Weimin; Gentry, Terry J.; Carley, Jack; Corbin, Gail A.; Carroll, Sue L.; Watson, David B.; Jardine, Phil M.; Zhou, Jizhong; Criddle, Craig S.; Fields, Matthew W.

    2009-05-22

    Bacterial community succession was investigated in a field-scale subsurface reactor formed by a series of wells that received weekly ethanol additions to re-circulating groundwater. Ethanol additions stimulated denitrification, metal reduction, sulfate reduction, and U(VI) reduction to sparingly soluble U(IV). Clone libraries of SSU rRNA gene sequences from groundwater samples enabled tracking of spatial and temporal changes over a 1.5 y period. Analyses showed that the communities changed in a manner consistent with geochemical variations that occurred along temporal and spatial scales. Canonical correspondence analysis revealed that the levels of nitrate, uranium, sulfide, sulfate, and ethanol strongly correlated with particular bacterial populations. As sulfate and U(VI) levels declined, sequences representative of sulfate-reducers and metal-reducers were detected at high levels. Ultimately, sequences associated with sulfate-reducing populations predominated, and sulfate levels declined as U(VI) remained at low levels. When engineering controls were compared to the population variation via canonical ordination, changes could be related to dissolved oxygen control and ethanol addition. The data also indicated that the indigenous populations responded differently to stimulation for bio-reduction; however, the two bio-stimulated communities became more similar after different transitions in an idiosyncratic manner. The strong associations between particular environmental variables and certain populations provide insight into the establishment of practical and successful remediation strategies in radionuclide-contaminated environments with respect to engineering controls and microbial ecology.

  8. Control of bacterial biofilm growth on surfaces by nanostructural mechanics and geometry

    Science.gov (United States)

    Epstein, A. K.; Hochbaum, A. I.; Kim, Philseok; Aizenberg, J.

    2011-12-01

    Surface-associated communities of bacteria, called biofilms, pervade natural and anthropogenic environments. Mature biofilms are resistant to a wide range of antimicrobial treatments and therefore pose persistent pathogenic threats. The use of surface chemistry to inhibit biofilm growth has been found to only transiently affect initial attachment. In this work, we investigate the tunable effects of physical surface properties, including high-aspect-ratio (HAR) surface nanostructure arrays recently reported to induce long-range spontaneous spatial patterning of bacteria on the surface. The functional parameters and length scale regimes that control such artificial patterning for the rod-shaped pathogenic species Pseudomonas aeruginosa are elucidated through a combinatorial approach. We further report a crossover regime of biofilm growth on a HAR nanostructured surface versus the nanostructure effective stiffness. When the 'softness' of the hair-like nanoarray is increased beyond a threshold value, biofilm growth is inhibited as compared to a flat control surface. This result is consistent with the mechanoselective adhesion of bacteria to surfaces. Therefore by combining nanoarray-induced bacterial patterning and modulating the effective stiffness of the nanoarray—thus mimicking an extremely compliant flat surface—bacterial mechanoselective adhesion can be exploited to control and inhibit biofilm growth.

  9. Activity Of Bacterial Proteolytic Enzymes on Antinutritional Factors in Soybeans and the Effect on Growth and Organ Weights of Piglets

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    A significant reduction of trypsin inhibitory activity by selected bacterial proteolytic enzymes was demon- strated in vitro. Two trials were conducted to examine the capacity of the tested enzymes to inactivate soybean ANFs in vivo. In trial I,twenty-four piglets weaned at four weeks of age were assigned in replicate groups of 4 piglets per pen to one of three dietary treatments: (1)control; (2)Enzyme 1-supplemented(E1); (3)Enzyme 2-supplemented (E2). In trial II,twenty piglets weaned at five weeks of age were alloted to five treatment di- ets:(1)contro,l: (2)0. 1% P4-supplemented; (3)0. 5% P4-supplemented; (4)0. 1% P7-supplemented; (5)0. 5% P7-supplemented. The optimum pH for hydrolysis was 8 for E,9-11 for E2,8.5 for P4 and nuctral for P7. After 17 days of the trial,daily gain of piglets on enzymes E1 and E2 was 36% and 18% more than that in the control group,although the difference was not significant. The animals on the treated groups had a tendency to have lighter heart(7.8 and 5.9%),spleen(11. 1 and 7.4%) and pancreas(16.7 and 12.5% for E1 and E2 respectively)in relation to empty body weight than those in the control. The small intestine of pigs on the treated groups was significantly lighter(18.9 for E1 and 7.7% for E2) than that in the control( P < 0.05 ). The stomach (26.4 and 24%,p=0. 198) and cecum(21.9and 9.4%,p=0. 114) also showed the same pat- tern. The growth depression was attributed to reduced feed intake caused by antinutritional factors in soy beans. It is concluded that supplements of proteolytic enzymes E1 or E2 had a positive effect on growth and ef- ficiency and caused much less reaction in the gut as manifested by the weight of the tract and of its accessory organs. Dietary saupplements of P4 or P7 had no significant effect on growth,but reduced reaction of soybean antinutritional factors in the gut,especialy P4 in dose of 0.5%. The growth depression was attributed to low feed intake caused by antinutritional

  10. Bacterial profiles of saliva in relation to diet, lifestyle factors, and socioeconomic status

    DEFF Research Database (Denmark)

    Belstrøm, Daniel; Holmstrup, Palle; Nielsen, Claus H

    2014-01-01

    BACKGROUND AND OBJECTIVE: The bacterial profile of saliva is composed of bacteria from different oral surfaces. The objective of this study was to determine whether different diet intake, lifestyle, or socioeconomic status is associated with characteristic bacterial saliva profiles. DESIGN......: Stimulated saliva samples from 292 participants with low levels of dental caries and periodontitis, enrolled in the Danish Health Examination Survey (DANHES), were analyzed for the presence of approximately 300 bacterial species by means of the Human Oral Microbe Identification Microarray (HOMIM). Using...... presence and levels (mean HOMIM-value) of bacterial probes as endpoints, the influence of diet intake, lifestyle, and socioeconomic status on the bacterial saliva profile was analyzed by Mann-Whitney tests with Benjamini-Hochberg's correction for multiple comparisons and principal component analysis...

  11. 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.

  12. Bacterial Community Composition and Potential Driving Factors in Different Reef Habitats of the Spermonde Archipelago, Indonesia

    Directory of Open Access Journals (Sweden)

    Hauke F. Kegler

    2017-04-01

    Full Text Available Coastal eutrophication is a key driver of shifts in bacterial communities on coral reefs. With fringing and patch reefs at varying distances from the coast the Spermonde Archipelago in southern Sulawesi, Indonesia offers ideal conditions to study the effects of coastal eutrophication along a spatially defined gradient. The present study investigated bacterial community composition of three coral reef habitats: the water column, sediments, and mucus of the hard coral genus Fungia, along that cross-shelf environmental and water quality gradient. The main research questions were: (1 How do water quality and bacterial community composition change along a coastal shelf gradient? (2 Which water quality parameters influence bacterial community composition? (3 Is there a difference in bacterial community composition among the investigated habitats? For this purpose, a range of key water parameters were measured at eight stations in distances from 2 to 55 km from urban Makassar. This was supplemented by sampling of bacterial communities of important microbial habitats using 454 pyrosequencing. Findings revealed that the population center Makassar had a strong effect on the concentrations of Chlorophyll a, suspended particulate matter (SPM, and transparent exopolymer particles (TEP, which were all significantly elevated at the inshore compared the other seven sites. Shifts in the bacterial communities were specific to each sampled habitat. Two OTUs, belonging to the genera Escherichia/Shigella (Gammaproteobacteria and Ralstonia (Betaproteobacteria, respectively, both dominated the bacterial community composition of the both size fractions of the water column and coral mucus. The sampled reef sediments were more diverse, and no single OTUs was dominant. There was no gradual shift in bacterial classes or OTUs within the sampled habitats. In addition, we observed very distinct communities between the investigated habitats. Our data show strong changes in the

  13. Listeria monocytogenes virulence factor Listeriolysin O favors bacterial growth in co-culture with the ciliate Tetrahymena pyriformis, causes protozoan encystment and promotes bacterial survival inside cysts

    Directory of Open Access Journals (Sweden)

    Ermolaeva Svetlana A

    2010-01-01

    Full Text Available Abstract Background The gram-positive pathogenic bacterium Listeria monocytogenes is widely spread in the nature. L. monocytogenes was reported to be isolated from soil, water, sewage and sludge. Listeriolysin O (LLO is a L. monocytogenes major virulence factor. In the course of infection in mammals, LLO is required for intracellular survival and apoptosis induction in lymphocytes. In this study, we explored the potential of LLO to promote interactions between L. monocytogenes and the ubiquitous inhabitant of natural ecosystems bacteriovorous free-living ciliate Tetrahymena pyriformis. Results Wild type L. monocytogenes reduced T. pyriformis trophozoite counts and stimulated encystment. The effects were observed starting from 48 h of co-incubation. On the day 14, trophozoites were eliminated from the co-culture while about 5 × 104 cells/ml remained in the axenic T. pyriformis culture. The deficient in the LLO-encoding hly gene L. monocytogenes strain failed to cause mortality among protozoa and to trigger protozoan encystment. Replenishment of the hly gene in the mutant strain restored toxicity towards protozoa and induction of protozoan encystment. The saprophytic non-haemolytic species L. innocua transformed with the LLO-expressing plasmid caused extensive mortality and encystment in ciliates. During the first week of co-incubation, LLO-producing L. monocytogenes demonstrated higher growth rates in association with T. pyriformis than the LLO-deficient isogenic strain. At latter stages of co-incubation bacterial counts were similar for both strains. T. pyriformis cysts infected with wild type L. monocytogenes caused listerial infection in guinea pigs upon ocular and oral inoculation. The infection was proved by bacterial plating from the internal organs. Conclusions The L. monocytogenes virulence factor LLO promotes bacterial survival and growth in the presence of bacteriovorous ciliate T. pyriformis. LLO is responsible for L. monocytogenes

  14. Restoring vaginal microbiota: biological control of bacterial vaginosis. A prospective case-control study using Lactobacillus rhamnosus BMX 54 as adjuvant treatment against bacterial vaginosis.

    Science.gov (United States)

    Recine, Nadia; Palma, Ettore; Domenici, Lavinia; Giorgini, Margherita; Imperiale, Ludovica; Sassu, Carolina; Musella, Angela; Marchetti, Claudia; Muzii, Ludovico; Benedetti Panici, Pierluigi

    2016-01-01

    Bacterial vaginosis (BV) is the most prevalent lower genital tract infection in reproductive-age women worldwide. BV is an ecological disorder of the vaginal microbiota characterized microbiologically by replacement of the lactobacilli, predominant vaginal microbiota. It is characterized by a high rate of relapse in sexual active women, and these patients show three or more relapses each year. A healthy vagina is characterized by hydrogen peroxide and acid-producing lactobacilli, which are crucial to maintain the physiological vaginal ecosystem and their depletion speeds up bacterial overgrowth with pH elevation, salidase and amine production, leading to the observed signs and symptoms of BV. The aim of this study is to evaluate the efficacy of long-term vaginal lactobacilli's implementation in restoring and maintaining vaginal microflora and pH and to collect data about prophylactic approach based on probiotics supplementation with lactobacilli. This is a prospective case-control study, performed between January 2013 and September 2014 at Department of Gynecological Obstetrics and Urologic Sciences of "Sapienza" University of Rome. 250 non-pregnant sexually active women with diagnoses of BV were collected. Patients selected were divided in Group A (125 patients assigned to standard treatment for BV-metronidazole 500 mg orally twice a day for 7 days) and Group B (125 women undergoing the same standard antibiotic regimen followed by vaginal tablets containing Lactobacillus rhamnosus BMX 54). Patients were evaluated after 2, 6, and 9 months (T0, T2, T6, and T9) in term of recurrences rates of BV, vaginal symptoms, re-establishment of healthy vaginal flora, vaginal pH, and treatment tolerability. Vaginal flora was significantly replaced in Group B patients after 2 months comparing with Group A (p = 0.014). These data were confirmed at 6 and 9 months follow-up: patients that underwent prophylactic therapy with NORMOGIN(®) experienced significantly low rate of

  15. Activity Of Bacterial Proteolytic Enzymes on Antinutritional Factors in Soybeans and the Effect on Growth and Organ Weights of Piglets

    Institute of Scientific and Technical Information of China (English)

    HuoGui-cheng; YangLi-jie; 等

    1999-01-01

    A significant reduction of trypsin inhibitory activity by selected bacterial proteolytic enzymes was demonstrated in vitro.Two trials were conducted to examine the capacity of the tested enzymes to inactivate soybean ANFs in vivo.In trial I,twenty-four piglets weaned at four weeks of age were assigned in replicate groups of 4 piglets per pen to one of three dietary treatments:(1)control;(2)Enzyme 1-supplemented(E1);(3)Enzyme 2-supplemented (E2).In trial II,twenty piglets weaned at five weeks of age were alloted to five treatment diets:(1)contro,1:(2) 0.1% P4-supplemented;(3)0.5% P4-supplemented;(4)0.1% P7-supplemented;(5)0.5% P7-supplemented.The optimum pH for hydrolysis was 8 for E.9-11 for E2,8.5 for P4 and nuctral for P7.After 17 days of the trial,daily gain of piglets on enzymes E1 and E2 was 36% and 18% more than that in the control group,although the difference was not significant.the animals on the treated groups had a tendency to have lighter heart(7.8 and 5.9%),spleen(11.1 and 7.4%) and pancreas(16.7 and 12.5% for E1 and E2 respectively)in relation to empty body weight than those in the control.the small intestine of pigs on the treated groups was significantly lighter(18.9 for E1 and 7.7% for E2) than that in the control(P<0.05).The stomach(26.4 and 24%,p=0.198) and cecum (21.9 and 9.4%,p=0.114) also showed the same pattern.The growth depression was attributed to reduced feed intake caused by antinutritional factors in soybeans.It is concluded that supplements of proteolytic enzymes E1 or E2 had a positive effect on growth and efficiency and caused much less reaction in the gut as manifested by the weight of the tract and of its accessory organs.Dietary saupplements of P4 or P7 had no significant effect on growth,but reduced reaction of soybean antinutritional factors in the gut,especialy P4 in dose of 0.5%.The growth depression was attributed to low feed intake caused by antinutritional factors in soybeans.

  16. A risk factors analysis of acute-on-chronic liver failure complicated by spontaneous bacterial peritonitis

    Directory of Open Access Journals (Sweden)

    LIU Zhengfang

    2017-04-01

    Full Text Available ObjectiveTo investigate the influencing factors for spontaneous bacterial peritonitis (SBP in patients with acute-on-chronic liver failure (ACLF, and to provide a reference for clinical diagnosis and prognosis evaluation. MethodsA retrospective analysis was performed for the clinical data of 667 patients with ACLF who were hospitalized and treated in our hospital from January 2009 to December 2014, and according to the presence or absence of SBP, they were divided into ACLF group(n=232 and ACLF-SBP group(n=435. The general information, laboratory markers, and incidence of complications were compared between the two groups. The t-test was used for comparison of normally distributed continuous data between groups, and the Mann-Whitney U test was used for non-normally distributed continuous data between groups; the chi-square test was used for comparison of categorical data between groups, and a logistic regression analysis was used to identify independent risk factors for ACLF complicated by SBP. ResultsThe comparison of laboratory markers and comorbidities showed that there were significant differences between the two groups in albumin (Alb (t=-4.110, P<0.001, alanine aminotransferase (U=-6.653, P<0.001, aspartate aminotransferase (t=-8.045, P<0.001, blood sodium (t=-2.879, P=0006, prothrombin time activity (t=-2.140, P=0.037, international normalized ratio (t=1.453, P=0.042, hemoglobin (t=-3.446, P=0.001, upper gastrointestinal bleeding (χ2=48.252, P=0.002, hepatorenal syndrome (χ2=16.244, P=0.031, and pulmonary infection (χ2=13.564, P<0.001. The multivariate logistic regression analysis showed that there were significant differences in Alb(OR=1.119,95%CI:1.052~1.189, platelet count (PLT(OR=1.035,95%CI:0.755~1.084, upper gastrointestinal bleeding(OR=1.117,95%CI:0.072~1.135, and pulmonary infection(OR=2.275,95%CI:0.978~5.292 (P=0.002,0.038,0.022, and 0.036. ConclusionIn the treatment of ACLF patients, risk factors including low Alb

  17. Prevalence of and risk factors for bacterial vaginosis among women of reproductive age attending cervical screening in southeastern Brazil.

    Science.gov (United States)

    Marconi, Camila; Duarte, Marli T C; Silva, Daniela C; Silva, Márcia G

    2015-11-01

    To determine the prevalence of and risk factors for bacterial vaginosis. A cross-sectional study of women aged 14-54 years attending 18 primary healthcare units in Botucatu, Brazil, for cervical screening was undertaken between September 1, 2012, and January 31, 2013. Data on sociodemographics, sexual behavior, and medical history were obtained by interview. Vaginal swabs were taken to classify the vaginal flora according to the Nugent scoring system. Candida sp. hyphae and infection by Trichomonas vaginalis were also evaluated by microscopy and culture, respectively. Stepwise logistic regression analysis was performed to identify risk factors independently associated with bacterial vaginosis. Among 1519 women included in analyses, 457 (30.1%) had bacterial vaginosis. Variables independently associated with bacterial vaginosis were a single marital status (OR 1.4; 95%CI 1.1-1.8), partner infidelity (OR 1.5; 95%CI 1.2-1.9), abnormal discharge in the previous year (OR 1.5; 95%CI 1.2-2.0), and concurrent trichomoniasis (OR 4.1; 95%CI 1.5-11.5). Current use of hormonal contraception (OR 0.7; 95%CI 0.5-0.9), luteal phase of menstrual cycle (OR 0.8; 95%CI 0.6-0.9), higher income (OR 0.8; 95%CI 0.6-0.9), and vaginal candidiasis (OR 0.5; 95%CI 0.3-0.9) all had protective effects. The prevalence of bacterial vaginosis in the study population is high. The epidemiological data provide evidence of the sexual transmissibility of bacterial vaginosis. Copyright © 2015 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

  18. Physicochemical control of bacterial and protist community composition and diversity in Antarctic sea ice.

    Science.gov (United States)

    Torstensson, Anders; Dinasquet, Julie; Chierici, Melissa; Fransson, Agneta; Riemann, Lasse; Wulff, Angela

    2015-10-01

    Due to climate change, sea ice experiences changes in terms of extent and physical properties. In order to understand how sea ice microbial communities are affected by changes in physicochemical properties of the ice, we used 454-sequencing of 16S and 18S rRNA genes to examine environmental control of microbial diversity and composition in Antarctic sea ice. We observed a high diversity and richness of bacteria, which were strongly negatively correlated with temperature and positively with brine salinity. We suggest that bacterial diversity in sea ice is mainly controlled by physicochemical properties of the ice, such as temperature and salinity, and that sea ice bacterial communities are sensitive to seasonal and environmental changes. For the first time in Antarctic interior sea ice, we observed a strong eukaryotic dominance of the dinoflagellate phylotype SL163A10, comprising 63% of the total sequences. This phylotype is known to be kleptoplastic and could be a significant primary producer in sea ice. We conclude that mixotrophic flagellates may play a greater role in the sea ice microbial ecosystem than previously believed, and not only during the polar night but also during summer when potential food sources are abundant.

  19. Bacterial colonization of the ovarian bursa in dogs with clinically suspected pyometra and in controls.

    Science.gov (United States)

    Rubio, Alejandro; Boyen, Filip; Tas, Olaf; Kitshoff, Adriaan; Polis, Ingeborgh; Van Goethem, Bart; de Rooster, Hilde

    2014-10-15

    Septic peritonitis occurs relatively commonly in dogs. Secondary septic peritonitis is usually associated with perforation of intestines or infected viscera, such as the uterus in pyometra cases. The aim of this study was to evaluate the bacterial flora in the ovarian bursae of intact bitches as a potential source of contamination. One hundred forty dogs, clinically suspected of pyometra, were prospectively enrolled. The control group consisted of 26 dogs that underwent elective ovariohysterectomies and 18 dogs with mammary gland tumors that were neutered at the time of mastectomy. Bacteriology samples were taken aseptically at the time of surgery from the bursae and the uterus in all dogs. Twenty-two dogs that were clinically suspected of pyometra had sterile uterine content ("mucometra" cases); the remaining 118 had positive uterine cultures ("pyometra" cases) and septic peritoneal fluid was present in 10% of these cases. Of the 118 pyometra cases, 9 had unilateral and 15 had bilateral bacterial colonization of their ovarian bursae. However, the bacteria from the ovarian bursa were similar to those recovered from the uterine pus in only half of the cases. Furthermore, positive bursae were also seen in one mucometra dog (unilateral) and in four control dogs (two unilateral and two bilateral). The data illustrate that the canine ovarian bursa can harbor bacteria. The biological importance of these isolations remains unclear. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Relationship among specific bacterial counts and total bacterial and somatic cell counts and factors influencing their variation in ovine bulk tank milk.

    Science.gov (United States)

    de Garnica, M L; Linage, B; Carriedo, J A; De La Fuente, L F; García-Jimeno, M C; Santos, J A; Gonzalo, C

    2013-02-01

    To analyze the relationship among the counts of different organisms and total bacterial count (BTTBC) and somatic cell count (BTSCC) as determined in dairy laboratories in ovine bulk tank milk, 751 bulk tank milk samples from 205 dairy sheep flocks belonging to Consortium for Ovine Promotion (CPO) were collected between January and December 2011. Four samplings were carried out in each flock, once per season, throughout 1 yr. Variables analyzed were bulk tank counts of thermoduric, psychrotrophic, coliform, and gram-positive catalase-negative cocci (GPCNC) bacterial groups. Thermoduric, psychrotrophic, and coliform species were significantly related to BTTBC, whereas GPCNC were correlated with both BTTBC and BTSCC variables. Highest counts were for psychrotroph and coliform groups, and a moderate to high correlation (r=0.51) was found between both variables, indicating that poor cleaning practices in the flocks tend to select for less-resistant organisms, such as gram-negative rods. In addition, BTTBC correlated with BTSCC (r=0.42). Some variation factors for specific bacterial counts, such as breed, season, milking type, dry therapy, and milk yield, were also analyzed. Flock information was collected from flock books, annual audits, and the CPO traceability system. Psychrotrophs and coliforms had elevated counts in winter, whereas GPCNC were higher in summer and in hand-milked flocks. Dry therapy contributed to the reduction in psychrotrophic bacteria; therefore, some strains of mammary pathogens could also be psychrotrophic bacteria. Results of this study would be helpful for troubleshooting milk quality problems and developing premium payment systems in dairy sheep.

  1. Bacterial foraging-optimized PID control of a two-wheeled machine with a two-directional handling mechanism.

    Science.gov (United States)

    Goher, K M; Fadlallah, S O

    2017-01-01

    This paper presents the performance of utilizing a bacterial foraging optimization algorithm on a PID control scheme for controlling a five DOF two-wheeled robotic machine with two-directional handling mechanism. The system under investigation provides solutions for industrial robotic applications that require a limited-space working environment. The system nonlinear mathematical model, derived using Lagrangian modeling approach, is simulated in MATLAB/Simulink(®) environment. Bacterial foraging-optimized PID control with decoupled nature is designed and implemented. Various working scenarios with multiple initial conditions are used to test the robustness and the system performance. Simulation results revealed the effectiveness of the bacterial foraging-optimized PID control method in improving the system performance compared to the PID control scheme.

  2. Factors influencing neurological outcome of children with bacterial meningitis at the emergency department.

    Science.gov (United States)

    Bargui, Fatiha; D'Agostino, Irene; Mariani-Kurkdjian, Patricia; Alberti, Corinne; Doit, Catherine; Bellier, Nathalie; Morin, Laurence; Galli Gibertini, Giuliano; Smail, Assia; Zanin, Anna; Lorrot, Mathie; Dauger, Stéphane; Neve, Mathieu; Faye, Albert; Armoogum, Priscilla; Bourrillon, Antoine; Bingen, Edouard; Mercier, Jean-Christophe; Bonacorsi, Stéphane; Nigrovic, Lise E; Titomanlio, Luigi

    2012-09-01

    We performed a cohort study of children who survived bacterial meningitis after the neonatal period at a single pediatric center in France over a 10-year period (1995-2004) to identify predictors of death and long-term neurological deficits in children with bacterial meningitis. We performed multivariate regression to determine independent predictors of death and neurologic deficits. We identified 101 children with bacterial meningitis of which 19 died during initial hospitalization. Need for mechanical ventilation [hazard ratio (HR) 11.5, 95 % confidence interval (CI) 2.4-55.5)] and thrombocytopenia defined as a platelet count highest risk.

  3. Environmental factors shaping cultured free-living amoebae and their associated bacterial community within drinking water network.

    Science.gov (United States)

    Delafont, Vincent; Bouchon, Didier; Héchard, Yann; Moulin, Laurent

    2016-09-01

    Free-living amoebae (FLA) constitute an important part of eukaryotic populations colonising drinking water networks. However, little is known about the factors influencing their ecology in such environments. Because of their status as reservoir of potentially pathogenic bacteria, understanding environmental factors impacting FLA populations and their associated bacterial community is crucial. Through sampling of a large drinking water network, the diversity of cultivable FLA and their bacterial community were investigated by an amplicon sequencing approach, and their correlation with physicochemical parameters was studied. While FLA ubiquitously colonised the water network all year long, significant changes in population composition were observed. These changes were partially explained by several environmental parameters, namely water origin, temperature, pH and chlorine concentration. The characterisation of FLA associated bacterial community reflected a diverse but rather stable consortium composed of nearly 1400 OTUs. The definition of a core community highlighted the predominance of only few genera, majorly dominated by Pseudomonas and Stenotrophomonas. Co-occurrence analysis also showed significant patterns of FLA-bacteria association, and allowed uncovering potentially new FLA - bacteria interactions. From our knowledge, this study is the first that combines a large sampling scheme with high-throughput identification of FLA together with associated bacteria, along with their influencing environmental parameters. Our results demonstrate the importance of physicochemical parameters in the ecology of FLA and their bacterial community in water networks.

  4. Bacterial community composition and potential driving factors in different reef habitats of the Spermonde Archipelago, Indonesia

    DEFF Research Database (Denmark)

    Kegler, Hauke F.; Lukman, Muhammad; Teichberg, Mirta

    2017-01-01

    Coastal eutrophication is a key driver of shifts in bacterial communities on coral reefs. With fringing and patch reefs at varying distances from the coast the Spermonde Archipelago in southern Sulawesi, Indonesia offers ideal conditions to study the effects of coastal eutrophication along...... a spatially defined gradient. The present study investigated bacterial community composition of three coral reef habitats: the water column, sediments, and mucus of the hard coral genus Fungia, along that cross shelf environmental and water quality gradient. The main research questions were: (1) How do water....../Shigella (Gammaproteobacteria) and Raistonia (Betaproteobacteria), respectively, both dominated the bacterial community composition of the both size fractions of the water column and coral mucus. The sampled reef sediments were more diverse, and no single OTUs was dominant. There was no gradual shift in bacterial classes...

  5. Local Environmental Factors Drive Divergent Grassland Soil Bacterial Communities in the Western Swiss Alps.

    Science.gov (United States)

    Yashiro, Erika; Pinto-Figueroa, Eric; Buri, Aline; Spangenberg, Jorge E; Adatte, Thierry; Niculita-Hirzel, Hélène; Guisan, Antoine; van der Meer, Jan Roelof

    2016-11-01

    Mountain ecosystems are characterized by a diverse range of climatic and topographic conditions over short distances and are known to shelter a high biodiversity. Despite important progress, still little is known on bacterial diversity in mountain areas. Here, we investigated soil bacterial biogeography at more than 100 sampling sites randomly stratified across a 700-km(2) area with 2,200-m elevation gradient in the western Swiss Alps. Bacterial grassland communities were highly diverse, with 12,741 total operational taxonomic units (OTUs) across 100 sites and an average of 2,918 OTUs per site. Bacterial community structure was correlated with local climatic, topographic, and soil physicochemical parameters with high statistical significance. We found pH (correlated with % CaO and % mineral carbon), hydrogen index (correlated with bulk gravimetric water content), and annual average number of frost days during the growing season to be among the groups of the most important environmental drivers of bacterial community structure. In contrast, bacterial community structure was only weakly stratified as a function of elevation. Contrasting patterns were discovered for individual bacterial taxa. Acidobacteria responded both positively and negatively to pH extremes. Various families within the Bacteroidetes responded to available phosphorus levels. Different verrucomicrobial groups responded to electrical conductivity, total organic carbon, water content, and mineral carbon contents. Alpine grassland bacterial communities are thus highly diverse, which is likely due to the large variety of different environmental conditions. These results shed new light on the biodiversity of mountain ecosystems, which were already identified as potentially fragile to anthropogenic influences and climate change. This article addresses the question of how microbial communities in alpine regions are dependent on local climatic and soil physicochemical variables. We benefit from a unique 700

  6. Prevalence of Bacterial Vaginosis and Associated Risk Factors among Women Complaining of Genital Tract Infection

    Directory of Open Access Journals (Sweden)

    Adane Bitew

    2017-01-01

    Full Text Available Background. Bacterial vaginosis is a global concern due to the increased risk of acquisition of sexually transmitted infections. Objectives. To determine the prevalence of bacterial vaginosis and bacteria causing aerobic vaginitis. Methods. A cross-sectional study was conducted among 210 patients between September 2015 and July 2016 at St. Paul’s Hospital. Gram-stained vaginal swabs were examined microscopically and graded as per Nugent’s procedure. Bacteria causing aerobic vaginitis were characterized, and their antimicrobial susceptibility pattern was determined. Results. The overall prevalence of bacterial vaginosis was 48.6%. Bacterial vaginosis was significantly associated with number of pants used per day (p=0.001 and frequency of vaginal bathing (p=0.045. Of 151 bacterial isolates, 69.5% were Gram-negative and 30.5% were Gram-positive bacteria. The overall drug resistance level of Gram-positive bacteria was high against penicillin, tetracycline, and erythromycin. Cefoxitin and tobramycin were the most active drugs against Gram-positive bacteria. The overall drug resistance level of Gram-negative bacteria was high against tetracycline, ampicillin, and amoxicillin. Amikacin and tobramycin were the most active drugs against Gram-negative bacteria. Conclusions. The prevalence of bacterial vaginosis was high and was affected by individual hygiene. Routine culture of vaginal samples should be performed on patients with vaginitis and the drug susceptibility pattern of each isolate should be determined.

  7. Prevalence of Bacterial Vaginosis and Associated Risk Factors among Women Complaining of Genital Tract Infection

    Science.gov (United States)

    Abebaw, Yeshiwork; Bekele, Delayehu; Mihret, Amete

    2017-01-01

    Background Bacterial vaginosis is a global concern due to the increased risk of acquisition of sexually transmitted infections. Objectives To determine the prevalence of bacterial vaginosis and bacteria causing aerobic vaginitis. Methods A cross-sectional study was conducted among 210 patients between September 2015 and July 2016 at St. Paul's Hospital. Gram-stained vaginal swabs were examined microscopically and graded as per Nugent's procedure. Bacteria causing aerobic vaginitis were characterized, and their antimicrobial susceptibility pattern was determined. Results The overall prevalence of bacterial vaginosis was 48.6%. Bacterial vaginosis was significantly associated with number of pants used per day (p = 0.001) and frequency of vaginal bathing (p = 0.045). Of 151 bacterial isolates, 69.5% were Gram-negative and 30.5% were Gram-positive bacteria. The overall drug resistance level of Gram-positive bacteria was high against penicillin, tetracycline, and erythromycin. Cefoxitin and tobramycin were the most active drugs against Gram-positive bacteria. The overall drug resistance level of Gram-negative bacteria was high against tetracycline, ampicillin, and amoxicillin. Amikacin and tobramycin were the most active drugs against Gram-negative bacteria. Conclusions The prevalence of bacterial vaginosis was high and was affected by individual hygiene. Routine culture of vaginal samples should be performed on patients with vaginitis and the drug susceptibility pattern of each isolate should be determined. PMID:28831285

  8. Prevalence of Bacterial Vaginosis and Associated Risk Factors among Women Complaining of Genital Tract Infection.

    Science.gov (United States)

    Bitew, Adane; Abebaw, Yeshiwork; Bekele, Delayehu; Mihret, Amete

    2017-01-01

    Bacterial vaginosis is a global concern due to the increased risk of acquisition of sexually transmitted infections. To determine the prevalence of bacterial vaginosis and bacteria causing aerobic vaginitis. A cross-sectional study was conducted among 210 patients between September 2015 and July 2016 at St. Paul's Hospital. Gram-stained vaginal swabs were examined microscopically and graded as per Nugent's procedure. Bacteria causing aerobic vaginitis were characterized, and their antimicrobial susceptibility pattern was determined. The overall prevalence of bacterial vaginosis was 48.6%. Bacterial vaginosis was significantly associated with number of pants used per day (p = 0.001) and frequency of vaginal bathing (p = 0.045). Of 151 bacterial isolates, 69.5% were Gram-negative and 30.5% were Gram-positive bacteria. The overall drug resistance level of Gram-positive bacteria was high against penicillin, tetracycline, and erythromycin. Cefoxitin and tobramycin were the most active drugs against Gram-positive bacteria. The overall drug resistance level of Gram-negative bacteria was high against tetracycline, ampicillin, and amoxicillin. Amikacin and tobramycin were the most active drugs against Gram-negative bacteria. The prevalence of bacterial vaginosis was high and was affected by individual hygiene. Routine culture of vaginal samples should be performed on patients with vaginitis and the drug susceptibility pattern of each isolate should be determined.

  9. Prevalence and factors associated with the occurrence of bacterial enteropathogens in suckling piglets in farrow-to-finish herds.

    Science.gov (United States)

    Dors, A; Czyżewska-Dors, E; Wasyl, D; Pomorska-Mól, M

    2016-12-10

    The aim of the study was to determine both environmental and infectious factors, influencing occurrence of bacterial enteropathogens in suckling piglets. For this purpose, a cross-sectional study in 70 Polish farrow-to-finish pig herds was performed. In each herd, presence of selected intestinal pathogens (Escherichia coli, Clostridium perfringens and Salmonella species) in faeces of suckling piglets were determined using bacteriological and PCR methods. Using logistic regression models, risk factors for enterotoxigenic E coli with fimbriae F4 (ETEC-F4) and C perfringens type A were established. Prevalence of bacterial enteropathogens in investigated herds was as follows (on herd and sample level): ETEC-F4 30.0 per cent and 9.3 per cent, respectively, C perfringens type A 91.4 per cent and 58.3 per cent, C perfringens type C 1.4 per cent and 0.3 per cent, Salmonella species 2.9 per cent and 0.5 per cent. The occurrence of ETEC-F4 was associated with presence of diarrhoea in piglets and vulval discharge in sows. Vulval discharge in sows, not slatted floor in farrowing pen and lack of coccidiosis prevention were determined as risk factors for C perfringens type A. The results obtained in the study revealed the high prevalence of enteropathogenic bacteria in pig herds and indicate management and organisation of production as factors having the greatest impact on the incidence of bacterial enteropathogens in piglets before weaning. British Veterinary Association.

  10. MHC class I expression dependent on bacterial infection and parental factors in whitefish embryos (Salmonidae).

    Science.gov (United States)

    Clark, Emily S; Wilkins, Laetitia G E; Wedekind, Claus

    2013-10-01

    Ecological conditions can influence not only the expression of a phenotype, but also the heritability of a trait. As such, heritable variation for a trait needs to be studied across environments. We have investigated how pathogen challenge affects the expression of MHC genes in embryos of the lake whitefish Coregonus palaea. In order to experimentally separate paternal (i.e. genetic) from maternal and environmental effects, and determine whether and how stress affects the heritable variation for MHC expression, embryos were produced in full-factorial in vitro fertilizations, reared singly, and exposed at 208 degree days (late-eyed stage) to either one of two strains of Pseudomonas fluorescens that differ in their virulence characteristics (one increased mortality, while both delayed hatching time). Gene expression was assessed 48 h postinoculation, and virulence effects of the bacterial infection were monitored until hatching. We found no evidence of MHC class II expression at this stage of development. MHC class I expression was markedly down-regulated in reaction to both pseudomonads. While MHC expression could not be linked to embryo survival, the less the gene was expressed, the earlier the embryos hatched within each treatment group, possibly due to trade-offs between immune function and developmental rate or further factors that affect both hatching timing and MHC expression. We found significant additive genetic variance for MHC class I expression in some treatments. That is, changes in pathogen pressures could induce rapid evolution in MHC class I expression. However, we found no additive genetic variance in reaction norms in our study population.

  11. Ras GTPase-like protein MglA, a controller of bacterial social-motility in Myxobacteria, has evolved to control bacterial predation by Bdellovibrio.

    Directory of Open Access Journals (Sweden)

    David S Milner

    2014-04-01

    Full Text Available Bdellovibrio bacteriovorus invade Gram-negative bacteria in a predatory process requiring Type IV pili (T4P at a single invasive pole, and also glide on surfaces to locate prey. Ras-like G-protein MglA, working with MglB and RomR in the deltaproteobacterium Myxococcus xanthus, regulates adventurous gliding and T4P-mediated social motility at both M. xanthus cell poles. Our bioinformatic analyses suggested that the GTPase activating protein (GAP-encoding gene mglB was lost in Bdellovibrio, but critical residues for MglA(Bd GTP-binding are conserved. Deletion of mglA(Bd abolished prey-invasion, but not gliding, and reduced T4P formation. MglA(Bd interacted with a previously uncharacterised tetratricopeptide repeat (TPR domain protein Bd2492, which we show localises at the single invasive pole and is required for predation. Bd2492 and RomR also interacted with cyclic-di-GMP-binding receptor CdgA, required for rapid prey-invasion. Bd2492, RomR(Bd and CdgA localize to the invasive pole and may facilitate MglA-docking. Bd2492 was encoded from an operon encoding a TamAB-like secretion system. The TamA protein and RomR were found, by gene deletion tests, to be essential for viability in both predatory and non-predatory modes. Control proteins, which regulate bipolar T4P-mediated social motility in swarming groups of deltaproteobacteria, have adapted in evolution to regulate the anti-social process of unipolar prey-invasion in the "lone-hunter" Bdellovibrio. Thus GTP-binding proteins and cyclic-di-GMP inputs combine at a regulatory hub, turning on prey-invasion and allowing invasion and killing of bacterial pathogens and consequent predatory growth of Bdellovibrio.

  12. Potential Environmental Factors Affecting Oil-Degrading Bacterial Populations in Deep and Surface Waters of the Northern Gulf of Mexico

    Science.gov (United States)

    Liu, Jiqing; Bacosa, Hernando P.; Liu, Zhanfei

    2017-01-01

    Understanding bacterial community dynamics as a result of an oil spill is important for predicting the fate of oil released to the environment and developing bioremediation strategies in the Gulf of Mexico. In this study, we aimed to elucidate the roles of temperature, water chemistry (nutrients), and initial bacterial community in selecting oil degraders through a series of incubation experiments. Surface (2 m) and bottom (1537 m) waters, collected near the Deepwater Horizon site, were amended with 200 ppm light Louisiana sweet crude oil and bacterial inoculums from surface or bottom water, and incubated at 4 or 24°C for 50 days. Bacterial community and residual oil were analyzed by pyrosequencing and gas chromatography-mass spectrometry (GC-MS), respectively. The results showed that temperature played a key role in selecting oil-degrading bacteria. Incubation at 4°C favored the development of Cycloclasticus, Pseudoalteromonas, Sulfitobacter, and Reinekea, while 24°C incubations enhanced Oleibacter, Thalassobius, Phaeobacter, and Roseobacter. Water chemistry and the initial community also had potential roles in the development of hydrocarbon-degrading bacterial communities. Pseudoalteromonas, Oleibacter, and Winogradskyella developed well in the nutrient-enriched bottom water, while Reinekea and Thalassobius were favored by low-nutrient surface water. We revealed that the combination of 4°C, crude oil and bottom inoculum was a key factor for the growth of Cycloclasticus, while the combination of surface inoculum and bottom water chemistry was important for the growth of Pseudoalteromonas. Moreover, regardless of the source of inoculum, bottom water at 24°C was a favorable condition for Oleibacter. Redundancy analysis further showed that temperature and initial community explained 57 and 19% of the variation observed, while oil and water chemistry contributed 14 and 10%, respectively. Overall, this study revealed the relative roles of temperature, water

  13. Spatially controlled bacterial adhesion using surface-patterned poly(ethylene glycol) hydrogels.

    Science.gov (United States)

    Krsko, Peter; Kaplan, Jeffrey B; Libera, Matthew

    2009-02-01

    We constructed surface-patterned hydrogels using low-energy focused electron beams to locally crosslink poly(ethylene glycol) (PEG) thin films on silanized glass substrates. Derived from electron-beam lithography, this technique was used to create patterned hydrogels with well-defined spatial positions and degrees of swelling. We found that cells of the bacterium Staphylococcus epidermidis adhered to and grew on the silanized glass substrates. These cells did not, however, adhere to surfaces covered by high-swelling lightly crosslinked PEG hydrogels. This finding is consistent with the cell-repulsiveness generally attributed to PEGylated surfaces. In contrast, S. epidermidis cells did adhere to surfaces covered by low-swelling highly crosslinked hydrogels. By creating precise patterns of repulsive hydrogels combined with adhesive hydrogels or with exposed glass substrate, we were able to spatially control the adhesion of S. epidermidis. Significantly, adhesive areas small enough to trap single bacterial cells could be fabricated. The results suggest that the lateral confinement imposed by cell-repulsive hydrogels hindered the cell proliferation and development into larger bacterial colonies.

  14. An Overview of the Control of Bacterial Pathogens in Cattle Manure

    Science.gov (United States)

    Manyi-Loh, Christy E.; Mamphweli, Sampson N.; Meyer, Edson L.; Makaka, Golden; Simon, Michael; Okoh, Anthony I.

    2016-01-01

    Cattle manure harbors microbial constituents that make it a potential source of pollution in the environment and infections in humans. Knowledge of, and microbial assessment of, manure is crucial in a bid to prevent public health and environmental hazards through the development of better management practices and policies that should govern manure handling. Physical, chemical and biological methods to reduce pathogen population in manure do exist, but are faced with challenges such as cost, odor pollution, green house gas emission, etc. Consequently, anaerobic digestion of animal manure is currently one of the most widely used treatment method that can help to salvage the above-mentioned adverse effects and in addition, produces biogas that can serve as an alternative/complementary source of energy. However, this method has to be monitored closely as it could be fraught with challenges during operation, caused by the inherent characteristics of the manure. In addition, to further reduce bacterial pathogens to a significant level, anaerobic digestion can be combined with other methods such as thermal, aerobic and physical methods. In this paper, we review the bacterial composition of cattle manure as well as methods engaged in the control of pathogenic microbes present in manure and recommendations that need to be respected and implemented in order to prevent microbial contamination of the environment, animals and humans. PMID:27571092

  15. An Overview of the Control of Bacterial Pathogens in Cattle Manure

    Directory of Open Access Journals (Sweden)

    Christy E. Manyi-Loh

    2016-08-01

    Full Text Available Cattle manure harbors microbial constituents that make it a potential source of pollution in the environment and infections in humans. Knowledge of, and microbial assessment of, manure is crucial in a bid to prevent public health and environmental hazards through the development of better management practices and policies that should govern manure handling. Physical, chemical and biological methods to reduce pathogen population in manure do exist, but are faced with challenges such as cost, odor pollution, green house gas emission, etc. Consequently, anaerobic digestion of animal manure is currently one of the most widely used treatment method that can help to salvage the above-mentioned adverse effects and in addition, produces biogas that can serve as an alternative/complementary source of energy. However, this method has to be monitored closely as it could be fraught with challenges during operation, caused by the inherent characteristics of the manure. In addition, to further reduce bacterial pathogens to a significant level, anaerobic digestion can be combined with other methods such as thermal, aerobic and physical methods. In this paper, we review the bacterial composition of cattle manure as well as methods engaged in the control of pathogenic microbes present in manure and recommendations that need to be respected and implemented in order to prevent microbial contamination of the environment, animals and humans.

  16. Model for the feedback control system of bacterial growth. II. Growth in continuous culture.

    Science.gov (United States)

    Bleecken, S

    1989-12-07

    A mathematical model is developed that describes substrate limited bacterial growth in a continuous culture and that is based upon the conceptual framework elaborated in a previous paper for describing the feedback control system of cell growth [S. Bleecken, (1988). J. theor. Biol. 133, 37.] Central to the theory are the ideas that the limiting substrate is converted into low molecular weight building blocks of macromolecular synthesis which again are converted into biomass (RNA and protein) and that the rates of RNA and protein synthesis are controlled by the intracellular concentration of building blocks. It is shown that a continuous culture can be simulated by two interconnected feedback control systems the actuating signals of which are limiting substrate concentration and the intracellular concentration of building blocks, respectively. Three types of steady-states are found to appear in a continuous culture, besides the well-known stable steady-state of the whole culture there exist two batchlike steady-states of the biotic part of the culture which are metastable. The model is used to analyse the steady-states and their stability properties as well as the dynamic responses of biomass, RNA, protein, building block and substrate concentrations to changes in environmental conditions. Especially the inoculation of a continuous culture and the effects of step changes in dilution rate, inlet substrate concentration and growth temperature are studied in detail. Relations between the growth behaviour of a single cell and that of a continuous culture are derived. The RNA to protein ratio is introduced as a rough measure of the physiological state of cells and it is shown that a cell reacts to environmental changes with a simple pattern of basic responses in growth rate and physiological state. There are reasons to assume that the model presented is the minimal version of a structured model of bacterial growth and represents an optimum compromise between biological

  17. Safety factor profile control in a tokamak

    CERN Document Server

    Bribiesca Argomedo, Federico; Prieur, Christophe

    2014-01-01

    Control of the Safety Factor Profile in a Tokamak uses Lyapunov techniques to address a challenging problem for which even the simplest physically relevant models are represented by nonlinear, time-dependent, partial differential equations (PDEs). This is because of the  spatiotemporal dynamics of transport phenomena (magnetic flux, heat, densities, etc.) in the anisotropic plasma medium. Robustness considerations are ubiquitous in the analysis and control design since direct measurements on the magnetic flux are impossible (its estimation relies on virtual sensors) and large uncertainties remain in the coupling between the plasma particles and the radio-frequency waves (distributed inputs). The Brief begins with a presentation of the reference dynamical model and continues by developing a Lyapunov function for the discretized system (in a polytopic linear-parameter-varying formulation). The limitations of this finite-dimensional approach motivate new developments in the infinite-dimensional framework. The t...

  18. The chloroplast transcription apparatus from mustard (Sinapis alba L.). Evidence for three different transcription factors which resemble bacterial sigma factors.

    Science.gov (United States)

    Tiller, K; Eisermann, A; Link, G

    1991-05-23

    A chloroplast protein fraction with sigma-like activity [Bülow, S. & Link, G. (1988) Plant Mol. Biol. 10, 349-357], was further purified and characterized. Chromatography on heparin-Sepharose, DEAE-Sepharose and Sephacryl S-300 led to the separation of three sigma-like factors (SLF) polypeptides with Mr 67,000 (SLF67), 52,000 (SLF52) and 29,000 (SLF29). None of these polypeptides bind to DNA itself, but each one confers enhanced binding and transcriptional activity when added to Escherichia coli RNA-polymerase core enzyme and DNA fragments carrying a chloroplast promoter. SLF67, SLF52, and SLF29 differ in their ionic-strength requirements for activity. They each mediate the binding to promoters of the chloroplast genes psbA, trnQ, and rps16, with different efficiencies. It is suggested that chloroplast transcription in vivo might be controlled at least in part by these functionally distinct factors.

  19. Soil pH and electrical conductivity are key edaphic factors shaping bacterial communities of greenhouse soils in Korea.

    Science.gov (United States)

    Kim, Jeong Myeong; Roh, An-Sung; Choi, Seung-Chul; Kim, Eun-Jeong; Choi, Moon-Tae; Ahn, Byung-Koo; Kim, Sun-Kuk; Lee, Young-Han; Joa, Jae-Ho; Kang, Seong-Soo; Lee, Shin Ae; Ahn, Jae-Hyung; Song, Jaekyeong; Weon, Hang-Yeon

    2016-12-01

    Soil microorganisms play an essential role in soil ecosystem processes such as organic matter decomposition, nutrient cycling, and plant nutrient availability. The land use for greenhouse cultivation has been increasing continuously, which involves an intensive input of agricultural materials to enhance productivity; however, relatively little is known about bacterial communities in greenhouse soils. To assess the effects of environmental factors on the soil bacterial diversity and community composition, a total of 187 greenhouse soil samples collected across Korea were subjected to bacterial 16S rRNA gene pyrosequencing analysis. A total of 11,865 operational taxonomic units at a 97% similarity cutoff level were detected from 847,560 sequences. Among nine soil factors evaluated; pH, electrical conductivity (EC), exchangeable cations (Ca(2+), Mg(2+), Na(+), and K(+)), available P2O5, organic matter, and NO3-N, soil pH was most strongly correlated with bacterial richness (polynomial regression, pH: R(2) = 0.1683, P pH: R(2) = 0.1765, P pH and EC (Mantel test, pH: r = 0.2672, P 1%), the relative abundances of Proteobacteria, Gemmatimonadetes, Acidobacteria, Bacteroidetes, Chloroflexi, and Planctomycetes were also more strongly correlated with pH and EC values, compared with other soil cation contents, such as Ca(2+), Mg(2+), Na(+), and K(+). Our results suggest that, despite the heterogeneity of various environmental variables, the bacterial communities of the intensively cultivated greenhouse soils were particularly influenced by soil pH and EC. These findings therefore shed light on the soil microbial ecology of greenhouse cultivation, which should be helpful for devising effective management strategies to enhance soil microbial diversity and improving crop productivity.

  20. Composite films of poly(vinyl alcohol)-chitosan-bacterial cellulose for drug controlled release.

    Science.gov (United States)

    Pavaloiu, Ramona-Daniela; Stoica-Guzun, Anicuta; Stroescu, Marta; Jinga, Sorin Ion; Dobre, Tanase

    2014-07-01

    Mono and multilayer composite films of poly(vinyl alcohol)-chitosan-bacterial cellulose (PVA/chitosan/BC) have been prepared to achieve controlled release of ibuprofen sodium salt (IbuNa) as model drug. The composite films have been characterized by Fourier transformed infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Surface morphology was investigated by scanning electron microscopy (SEM). Equilibrium swelling was measured in water at two different pH values and in vitro release of IbuNa in pH 1.2 and pH 7.4 media was studied. The release experiments revealed that drug release is pH sensitive. The release kinetics of IbuNa could be described by the Fickian model of diffusion with a good agreement. The IbuNa release rate was decreasing for all the films as the BC concentration was increased in the films composition, the decrease being higher for the multilayer films.

  1. Implant surface factors and bacterial adhesion: a review of the literature.

    Science.gov (United States)

    Yeo, In-Sung; Kim, Ha-Young; Lim, Kyung Sub; Han, Jung-Suk

    2012-10-01

    The microbiota that forms on implant surfaces placed in the human body can be highly resistant to antimicrobial agents and in some cases cause life-threatening infections. Consequently, to limit bacterial attachment to these surfaces and thereby minimize the risk of implant infection, the process of biofilm formation and bacterial attachment must be well-understood. The oral environment is considered to be an excellent model for research into biofilm formation and implant infection, accounting for many studies carried out in the field of dental medicine. Those studies show that the roughness, free energy, and material characteristics of the implant surface largely determine initial bacterial adhesion. This article reviews the relevant literature on these aspects of biofilm formation.

  2. The carboxyl terminus of RAP30 is similar in sequence to region 4 of bacterial sigma factors and is required for function.

    Science.gov (United States)

    Garrett, K P; Serizawa, H; Hanley, J P; Bradsher, J N; Tsuboi, A; Arai, N; Yokota, T; Arai, K; Conaway, R C; Conaway, J W

    1992-11-25

    Transcription factor beta gamma (RAP30/74) from rat liver was previously shown in biochemical studies to control the binding of RNA polymerase II to promoters by a mechanism analogous to that utilized by bacterial sigma factors, by decreasing the affinity of polymerase for nonpromoter sites on DNA and by increasing the affinity of the enzyme for the preinitiation complex (Conaway, R. C., Garrett, K. P., Hanley, J. P., and Conaway, J. W. (1991) Proc. Natl. Acad. Sci. U.S.A. 88, 6205-6209). By constructing and analyzing mutants of beta gamma, we have identified a novel functional domain located in the carboxyl terminus of the gamma (RAP30) subunit. This domain shares sequence similarity with region 4 of bacterial sigma factors; in particular, it exhibits striking similarity to the carboxyl-terminal regions 4.1 and 4.2 of SpoIIIC (Bacillus subtilis sigma k). Evidence from biochemical studies argues that a mutant gamma (RAP30), lacking amino acid sequences similar to sigma homology region 4.2, is able to assemble with the beta (RAP74) subunit to form a mutant beta gamma (RAP30/74) with impaired ability to interact with RNA polymerase II.

  3. Increasing the dynamic control space of mammalian transcription devices by combinatorial assembly of homologous regulatory elements from different bacterial species.

    Science.gov (United States)

    Bacchus, William; Weber, Wilfried; Fussenegger, Martin

    2013-01-01

    Prokaryotic transcriptional regulatory elements are widely utilized building blocks for constructing regulatory genetic circuits adapted for mammalian cells and have found their way into a broad range of biotechnological applications. Prokaryotic transcriptional repressors, fused to eukaryotic transactivation or repression domains, compose the transcription factor, which binds and adjusts transcription from chimeric promoters containing the repressor-specific operator sequence. Escherichia coli and Chlamydia trachomatis share common features in the regulatory mechanism of the biosynthesis of l-tryptophan. The repressor protein TrpR of C. trachomatis regulates the trpRBA operon and the TrpR of E. coli regulates the trpEDCBA operon, both requiring l-tryptophan as a co-repressor. Fusion of these bacterial repressors to the VP16 transactivation domain of Herpes simplex virus creates synthetic transactivators that could bind and activate chimeric promoters, assembled by placing repressor-specific operator modules adjacent to a minimal promoter, in an l-tryptophan-adjustable manner. Combinations of different transactivator and promoter variants from the same or different bacterial species resulted in a multitude of regulatory systems where l-tryptophan regulation properties, background noise, and maximal gene expression levels were significantly diverse. Different l-tryptophan analogues showed diverse regulatory capacity depending on the promoter/transactivator combination. We believe the systems approach to rationally choose promoters, transactivators and inducer molecules, to obtain desired and predefined genetic expression dynamics and control profiles, will significantly advance the design of new regulatory circuits as well as improving already existing ones. Copyright © 2012 Elsevier Inc. All rights reserved.

  4. Novel cyclic di-GMP effectors of the YajQ protein family control bacterial virulence.

    Science.gov (United States)

    An, Shi-qi; Caly, Delphine L; McCarthy, Yvonne; Murdoch, Sarah L; Ward, Joseph; Febrer, Melanie; Dow, J Maxwell; Ryan, Robert P

    2014-10-01

    Bis-(3',5') cyclic di-guanylate (cyclic di-GMP) is a key bacterial second messenger that is implicated in the regulation of many critical processes that include motility, biofilm formation and virulence. Cyclic di-GMP influences diverse functions through interaction with a range of effectors. Our knowledge of these effectors and their different regulatory actions is far from complete, however. Here we have used an affinity pull-down assay using cyclic di-GMP-coupled magnetic beads to identify cyclic di-GMP binding proteins in the plant pathogen Xanthomonas campestris pv. campestris (Xcc). This analysis identified XC_3703, a protein of the YajQ family, as a potential cyclic di-GMP receptor. Isothermal titration calorimetry showed that the purified XC_3703 protein bound cyclic di-GMP with a high affinity (K(d)∼2 µM). Mutation of XC_3703 led to reduced virulence of Xcc to plants and alteration in biofilm formation. Yeast two-hybrid and far-western analyses showed that XC_3703 was able to interact with XC_2801, a transcription factor of the LysR family. Mutation of XC_2801 and XC_3703 had partially overlapping effects on the transcriptome of Xcc, and both affected virulence. Electromobility shift assays showed that XC_3703 positively affected the binding of XC_2801 to the promoters of target virulence genes, an effect that was reversed by cyclic di-GMP. Genetic and functional analysis of YajQ family members from the human pathogens Pseudomonas aeruginosa and Stenotrophomonas maltophilia showed that they also specifically bound cyclic di-GMP and contributed to virulence in model systems. The findings thus identify a new class of cyclic di-GMP effector that regulates bacterial virulence.

  5. Novel cyclic di-GMP effectors of the YajQ protein family control bacterial virulence.

    Directory of Open Access Journals (Sweden)

    Shi-qi An

    2014-10-01

    Full Text Available Bis-(3',5' cyclic di-guanylate (cyclic di-GMP is a key bacterial second messenger that is implicated in the regulation of many critical processes that include motility, biofilm formation and virulence. Cyclic di-GMP influences diverse functions through interaction with a range of effectors. Our knowledge of these effectors and their different regulatory actions is far from complete, however. Here we have used an affinity pull-down assay using cyclic di-GMP-coupled magnetic beads to identify cyclic di-GMP binding proteins in the plant pathogen Xanthomonas campestris pv. campestris (Xcc. This analysis identified XC_3703, a protein of the YajQ family, as a potential cyclic di-GMP receptor. Isothermal titration calorimetry showed that the purified XC_3703 protein bound cyclic di-GMP with a high affinity (K(d∼2 µM. Mutation of XC_3703 led to reduced virulence of Xcc to plants and alteration in biofilm formation. Yeast two-hybrid and far-western analyses showed that XC_3703 was able to interact with XC_2801, a transcription factor of the LysR family. Mutation of XC_2801 and XC_3703 had partially overlapping effects on the transcriptome of Xcc, and both affected virulence. Electromobility shift assays showed that XC_3703 positively affected the binding of XC_2801 to the promoters of target virulence genes, an effect that was reversed by cyclic di-GMP. Genetic and functional analysis of YajQ family members from the human pathogens Pseudomonas aeruginosa and Stenotrophomonas maltophilia showed that they also specifically bound cyclic di-GMP and contributed to virulence in model systems. The findings thus identify a new class of cyclic di-GMP effector that regulates bacterial virulence.

  6. Epidemiology and Control of Strawberry Bacterial Angular Leaf Spot Disease Caused by Xanthomonas fragariae.

    Science.gov (United States)

    Kim, Da-Ran; Gang, Gun-Hye; Jeon, Chang-Wook; Kang, Nam Jun; Lee, Sang-Woo; Kwak, Youn-Sig

    2016-08-01

    Strawberry bacterial angular leaf spot (ALS) disease, caused by Xanthomonas fragariae has become increasingly problematic in the strawberry agro-industry. ALS causes small angular water-soaked lesions to develop on the abaxial leaf surface. Studies reported optimum temperature conditions for X. fragariae are 20°C and the pathogen suffers mortality above 32°C. However, at the nursery stage, disease symptoms have been observed under high temperature conditions. In the present study, results showed X. fragariae transmission was via infected maternal plants, precipitation, and sprinkler irrigation systems. Systemic infections were detected using X. fragariae specific primers 245A/B and 295A/B, where 300-bp and 615-bp were respectively amplified. During the nursery stage (from May to August), the pathogen was PCR detected only in maternal plants, but not in soil or irrigation water through the nursery stage. During the cultivation period, from September to March, the pathogen was detected in maternal plants, progeny, and soil, but not in water. Additionally, un-infected plants, when planted with infected plants were positive for X. fragariae via PCR at the late cultivation stage. Chemical control for X. fragariae with oxolinic acid showed 87% control effects against the disease during the nursery period, in contrast to validamycin-A, which exhibited increased efficacy against the disease during the cultivation stage (control effect 95%). To our knowledge, this is the first epidemiological study of X. fragariae in Korean strawberry fields.

  7. Computational design of a Zn2+ receptor that controls bacterial gene expression

    Science.gov (United States)

    Dwyer, M. A.; Looger, L. L.; Hellinga, H. W.

    2003-09-01

    The control of cellular physiology and gene expression in response to extracellular signals is a basic property of living systems. We have constructed a synthetic bacterial signal transduction pathway in which gene expression is controlled by extracellular Zn2+. In this system a computationally designed Zn2+-binding periplasmic receptor senses the extracellular solute and triggers a two-component signal transduction pathway via a chimeric transmembrane protein, resulting in transcriptional up-regulation of a -galactosidase reporter gene. The Zn2+-binding site in the designed receptor is based on a four-coordinate, tetrahedral primary coordination sphere consisting of histidines and glutamates. In addition, mutations were introduced in a secondary coordination sphere to satisfy the residual hydrogen-bonding potential of the histidines coordinated to the metal. The importance of the secondary shell interactions is demonstrated by their effect on metal affinity and selectivity, as well as protein stability. Three designed protein sequences, comprising two distinct metal-binding positions, were all shown to bind Zn2+ and to function in the cell-based assay, indicating the generality of the design methodology. These experiments demonstrate that biological systems can be manipulated with computationally designed proteins that have drastically altered ligand-binding specificities, thereby extending the repertoire of genetic control by extracellular signals.

  8. Epidemiology and Control of Strawberry Bacterial Angular Leaf Spot Disease Caused by Xanthomonas fragariae

    Directory of Open Access Journals (Sweden)

    Da-Ran Kim

    2016-08-01

    Full Text Available Strawberry bacterial angular leaf spot (ALS disease, caused by Xanthomonas fragariae has become increasingly problematic in the strawberry agro-industry. ALS causes small angular water-soaked lesions to develop on the abaxial leaf surface. Studies reported optimum temperature conditions for X. fragariae are 20°C and the pathogen suffers mortality above 32°C. However, at the nursery stage, disease symptoms have been observed under high temperature conditions. In the present study, results showed X. fragariae transmission was via infected maternal plants, precipitation, and sprinkler irrigation systems. Systemic infections were detected using X. fragariae specific primers 245A/B and 295A/B, where 300-bp and 615-bp were respectively amplified. During the nursery stage (from May to August, the pathogen was PCR detected only in maternal plants, but not in soil or irrigation water through the nursery stage. During the cultivation period, from September to March, the pathogen was detected in maternal plants, progeny, and soil, but not in water. Additionally, un-infected plants, when planted with infected plants were positive for X. fragariae via PCR at the late cultivation stage. Chemical control for X. fragariae with oxolinic acid showed 87% control effects against the disease during the nursery period, in contrast to validamycin-A, which exhibited increased efficacy against the disease during the cultivation stage (control effect 95%. To our knowledge, this is the first epidemiological study of X. fragariae in Korean strawberry fields.

  9. Etiology and Risk Factors of Acute Gastroenteritis in a Taipei Emergency Department: Clinical Features for Bacterial Gastroenteritis

    Directory of Open Access Journals (Sweden)

    Chao-Chih Lai

    2016-04-01

    Full Text Available Background: The causative pathogen is rarely identified in the emergency department (ED, since the results of cultures are usually unavailable. As a result, antimicrobial treatment may be overused. The aim of our study was to investigate the pathogens, risk factors of acute gastroenteritis, and predictors of acute bacterial gastroenteritis in the ED. Methods: We conducted a matched case-control study of 627 stool samples and 612 matched pairs. Results: Viruses (41.3% were the leading cause of gastroenteritis, with noroviruses (32.2% being the most prevalent, followed by bacteria (26.8% and Giardia lamblia (12.4%. Taking antacids (adjusted odds ratio [aOR] 4.10; 95% confidence interval [CI], 2.57–6.53, household members/classmates with gastroenteritis (aOR 4.69; 95% CI, 2.76–7.96, attending a banquet (aOR 2.29; 95% CI, 1.64–3.20, dining out (aOR 1.70; 95% CI, 1.13–2.54, and eating raw oysters (aOR 3.10; 95% CI, 1.61–5.94 were highly associated with gastroenteritis. Elders (aOR 1.04; 05% CI, 1.02–1.05, those with CRP >10 mg/L (aOR 2.04; 95% CI, 1.15–3.62, or those who were positive for fecal leukocytes (aOR 2.04; 95% CI, 1.15–3.62 or fecal occult blood (aOR 1.97; 95% CI, 1.03–3.77 were more likely to be hospitalized in ED. In addition, presence of fecal leukocytes (time ratio [TR] 1.22; 95% CI, 1.06–1.41, abdominal pain (TR 1.20; 95% CI, 1.07–1.41, and frequency of vomiting (TR 0.79; 95% CI, 0.64–0.98 were significantly associated with the duration of acute gastroenteritis. Presence of fecal leukocytes (aOR 2.08; 95% CI, 1.42–3.05, winter season (aOR 0.45; 95% CI, 0.28–0.74, frequency of diarrhea (aOR 1.69; 95% CI, 1.01–2.83, and eating shrimp or crab (aOR 1.53; 95% CI, 1.05–2.23 were highly associated with bacterial gastroenteritis. The area under the receiver operating characteristic curve of the final model was 0.68 (95% CI, 0.55–0.63. Conclusions: Acute bacterial gastroenteritis was highly associated with

  10. Bacterial and fungal endophthalmitis in Upper Egypt: related species and risk factors

    Directory of Open Access Journals (Sweden)

    AA Gharamah

    2012-08-01

    Conclusions: The ability of bacterial and fungal isolates to produce extracellular enzymes and mycotoxins may be aid in the invasion and destruction of eye tissues. Microbial contamination of operating rooms with air-borne bacteria and fungi in the present work may be a source of postoperative endophthalmitis.

  11. Factors controlling contrail cirrus optical depth

    Directory of Open Access Journals (Sweden)

    B. Kärcher

    2009-08-01

    Full Text Available Aircraft contrails develop into contrail cirrus by depositional growth and sedimentation of ice particles and horizontal spreading due to wind shear. Factors controlling this development include temperature, ice supersaturation, thickness of ice-supersaturated layers, and vertical gradients in the horizontal wind field. An analytical microphysical cloud model is presented and validated that captures these processes. Many individual contrail cirrus are simulated that develop differently owing to the variability in the controlling factors, resulting in large samples of cloud properties that are statistically analyzed. Contrail cirrus development is studied over the first four hours past formation, similar to the ages of line-shaped contrails that were tracked in satellite imagery on regional scales. On these time scales, contrail cirrus optical depth and microphysical variables exhibit a marked variability, expressed in terms of broad and skewed probability distribution functions. Simulated mean optical depths at a wavelength of 0.55 μm range from 0.05-0.5 and a substantial fraction 20-50% of contrail cirrus stay subvisible (optical depth <0.02, depending on meteorological conditions.

    A detailed analysis based on an observational case study over the continental USA suggests that previous satellite measurements of line-shaped persistent contrails have missed about 89%, 50%, and 11% of contrails with optical depths 0-0.05, 0.05-0.1, and 0.1-0.2, respectively, amounting to 65% of contrail coverage of all optical depths. When comparing observations with simulations and when estimating the contrail cirrus climate impact, not only mean values but also the variability in optical depth and microphysical properties need to be considered.

  12. Invasive Fungal Rhinosinusitis versus Bacterial Rhinosinusitis with Orbital Complications: A Case-Control Study

    OpenAIRE

    2013-01-01

    Background. Invasive fungal rhinosinusitis with orbital complications (IFSwOC) is a life-threatening condition. The incidence of mortality has been reported to be up to 80 percent. This study was conducted to determine the risk factors, presentations, clinical, and imaging findings that could help to manage this condition promptly. Methods. We conducted a case-control study of 100 patients suffering from rhinosinusitis with orbital complications. The risk factors, clinical presentations, radi...

  13. Factors Affecting Mortality and Morbidity of Patients With Cirrhosis Hospitalized for Spontaneous Bacterial Peritonitis.

    Science.gov (United States)

    Ensaroğlu, Fatih; Korkmaz, Murat; Geçkil, Ali Ümit; Öcal, Serkan; Koç, Bengisu; Yıldız, Özgün; Atalay, Fatma Büşra; Taş, Emine Gül; Haberal, Mehmet

    2015-11-01

    Spontaneous bacterial peritonitis, unless originating from surgery or an intra-abdominal source, is an infection diagnosed by neutrophil counts greater than 250/mm³ in ascites. Spontaneous bacterial peritonitis is the most common infection among patients hospitalized with cirrhosis, with a prevalence of 9% and a risk of development among all patients with cirrhosis within 1 year of 10%. No valid parameters have been defined to predict the mortality related to spontaneous bacterial peritonitis. Unless it is treated, the mortality rate as a result of spontaneous bacterial peritonitis is 50%, and serious complications may arise. Medical records from 29 patients on the deceased-donor transplant waiting list and receiving treatment at the Başkent University Hospital Gastroenterology Clinic for cirrhotic ascites infection between 1996 and 2013 were analyzed. Demographic information, paracentesis findings, clinical follow-up, and treatment results were reviewed and collected from patient medical records, with data recorded to the research form. In our patient group, 72.4% were men and the average age was 46.6 years. Most of our patients were at advanced stage, with 55.2% having a Child-Pugh score of C and an average Model for End-Stage Liver Disease score of 17 ± 4.1. We found that 34.5% of the patients received prophylactic treatment for spontaneous bacterial peritonitis, 72.4% received a proton pump inhibitor, and 82.8% had treatment with intravenous albumin support at the time of diagnosis. Albumin treatment showed no effect on mortality. Mortality rate among patients with Child-Pugh score of C was 81.3%. Existence of chronic renal failure, liver graft surgery, and hepatocellular cancer did not seem to have a significant effect on patient mortality. The albumin treatment protocol showed no significant difference despite common belief among physicians.

  14. Dexamethasone therapy for bacterial meningitis. Results of two double-blind, placebo-controlled trials.

    Science.gov (United States)

    Lebel, M H; Freij, B J; Syrogiannopoulos, G A; Chrane, D F; Hoyt, M J; Stewart, S M; Kennard, B D; Olsen, K D; McCracken, G H

    1988-10-13

    We enrolled 200 infants and older children with bacterial meningitis in two prospective double-blind, placebo-controlled trials to evaluate the efficacy of dexamethasone therapy in addition to either cefuroxime (Study 1) or ceftriaxone (Study 2). Altogether, 98 patients received placebo and 102 received dexamethasone (0.15 mg per kilogram of body weight every six hours for four days). At the beginning of therapy, the clinical and demographic characteristics of the patients in the treatment groups were comparable. The mean increase in the cerebrospinal fluid concentration of glucose and the decreases in lactate and protein levels after 24 hours of therapy were significantly greater in those who received dexamethasone than in those who received placebo (glucose, 2.0 vs. 0.4 mmol per liter [36.0 vs. 6.9 mg per deciliter], P less than 0.001; lactate, 4.0 vs. 2.1 mmol per liter [38.3 vs. 19.8 mg per deciliter], P less than 0.001; and protein, 0.64 vs. 0.25 g per liter [64.0 vs. 25.3 mg per deciliter], P less than 0.05). One patient in the placebo group in Study 1 died. As compared with those who received placebo, the patients who received dexamethasone became afebrile earlier (1.6 vs. 5.0 days; P less than 0.001) and were less likely to acquire moderate or more severe bilateral sensorineural hearing loss (15.5 vs. 3.3 percent; P less than 0.01). Twelve patients in the two placebo groups (14 percent) had severe or profound bilateral hearing loss requiring the use of a hearing aid, as compared with 1 (1 percent) in the two dexamethasone groups (P less than 0.001). We conclude that dexamethasone is beneficial in the treatment of infants and children with bacterial meningitis, particularly in preventing deafness.

  15. Propionibacterium acnes CAMP factor and host acid sphingomyelinase contribute to bacterial virulence: potential targets for inflammatory acne treatment.

    Directory of Open Access Journals (Sweden)

    Teruaki Nakatsuji

    Full Text Available BACKGROUND: In the progression of acne vulgaris, the disruption of follicular epithelia by an over-growth of Propionibacterium acnes (P. acnes permits the bacteria to spread and become in contact with various skin and immune cells. METHODOLOGY/PRINCIPAL FINDINGS: We have demonstrated in the present study that the Christie, Atkins, Munch-Peterson (CAMP factor of P. acnes is a secretory protein with co-hemolytic activity with sphingomyelinase that can confer cytotoxicity to HaCaT keratinocytes and RAW264.7 macrophages. The CAMP factor from bacteria and acid sphingomyelinase (ASMase from the host cells were simultaneously present in the culture supernatant only when the cells were co-cultured with P. acnes. Either anti-CAMP factor serum or desipramine, a selective ASMase inhibitor, significantly abrogated the P. acnes-induced cell death of HaCaT and RAW264.7 cells. Intradermal injection of ICR mouse ears with live P. acnes induced considerable ear inflammation, macrophage infiltration, and an increase in cellular soluble ASMase. Suppression of ASMase by systemic treatment with desipramine significantly reduced inflammatory reaction induced by intradermal injection with P. acnes, suggesting the contribution of host ASMase in P. acnes-induced inflammatory reaction in vivo. Vaccination of mice with CAMP factor elicited a protective immunity against P. acnes-induced ear inflammation, indicating the involvement of CAMP factor in P. acnes-induced inflammation. Most notably, suppression of both bacterial CAMP factor and host ASMase using vaccination and specific antibody injection, respectively, cooperatively alleviated P. acnes-induced inflammation. CONCLUSIONS/SIGNIFICANCE: These findings envision a novel infectious mechanism by which P. acnes CAMP factor may hijack host ASMase to amplify bacterial virulence to degrade and invade host cells. This work has identified both CAMP factor and ASMase as potential molecular targets for the development of drugs

  16. The Oral Bacterial Communities of Children with Well-Controlled HIV Infection and without HIV Infection.

    Directory of Open Access Journals (Sweden)

    Brittany E Goldberg

    Full Text Available The oral microbial community (microbiota plays a critical role in human health and disease. Alterations in the oral microbiota may be associated with disorders such as gingivitis, periodontitis, childhood caries, alveolar osteitis, oral candidiasis and endodontic infections. In the immunosuppressed population, the spectrum of potential oral disease is even broader, encompassing candidiasis, necrotizing gingivitis, parotid gland enlargement, Kaposi's sarcoma, oral warts and other diseases. Here, we used 454 pyrosequencing of bacterial 16S rRNA genes to examine the oral microbiome of saliva, mucosal and tooth samples from HIV-positive and negative children. Patient demographics and clinical characteristics were collected from a cross-section of patients undergoing routine dental care. Multiple specimens from different sampling sites in the mouth were collected for each patient. The goal of the study was to observe the potential diversity of the oral microbiota among individual patients, sample locations, HIV status and various dental characteristics. We found that there were significant differences in the microbiome among the enrolled patients, and between sampling locations. The analysis was complicated by uneven enrollment in the patient cohorts, with only five HIV-negative patients enrolled in the study and by the rapid improvement in the health of HIV-infected children between the time the study was conceived and completed. The generally good oral health of the HIV-negative patients limited the number of dental plaque samples that could be collected. We did not identify significant differences between well-controlled HIV-positive patients and HIV-negative controls, suggesting that well-controlled HIV-positive patients essentially harbor similar oral flora compared to patients without HIV. Nor were significant differences in the oral microbiota identified between different teeth or with different dental characteristics. Additional studies are

  17. Identification of inhibitors of a bacterial sigma factor using a new high-throughput screening assay.

    Science.gov (United States)

    El-Mowafi, S A; Sineva, E; Alumasa, J N; Nicoloff, H; Tomsho, J W; Ades, S E; Keiler, K C

    2015-01-01

    Gram-negative bacteria are formidable pathogens because their cell envelope presents an adaptable barrier to environmental and host-mediated challenges. The stress response pathway controlled by the alternative sigma factor σ(E) is critical for maintenance of the cell envelope. Because σ(E) is required for the virulence or viability of several Gram-negative pathogens, it might be a useful target for antibiotic development. To determine if small molecules can inhibit the σ(E) pathway, and to permit high-throughput screening for antibiotic lead compounds, a σ(E) activity assay that is compatible with high-throughput screening was developed and validated. The screen employs a biological assay with positive readout. An Escherichia coli strain was engineered to express yellow fluorescent protein (YFP) under negative regulation by the σ(E) pathway, such that inhibitors of the pathway increase the production of YFP. To validate the screen, the reporter strain was used to identify σ(E) pathway inhibitors from a library of cyclic peptides. Biochemical characterization of one of the inhibitory cyclic peptides showed that it binds σ(E), inhibits RNA polymerase holoenzyme formation, and inhibits σ(E)-dependent transcription in vitro. These results demonstrate that alternative sigma factors can be inhibited by small molecules and enable high-throughput screening for inhibitors of the σ(E) pathway.

  18. Detection of Pneumocystis DNA in samples from patients suspected of bacterial pneumonia – a case-control study

    DEFF Research Database (Denmark)

    Helweg-Larsen, J; Jensen, JS; Dohn, G

    2002-01-01

    Pneumocystis jiroveci (formerly known as P. carinii f.sp. hominis) is an opportunistic fungus that causes Pneumocystis pneumonia (PCP) in immunocompromised individuals. Pneumocystis jiroveci can be detected by polymerase chain reaction (PCR). To investigate the clinical importance of a positive...... Pneumocystis-PCR among HIV-uninfected patients suspected of bacterial pneumonia, a retrospective matched case-control study was conducted....

  19. Bacterial ‘cosmopolitanism’ and importance of local environmental factors for community composition in remote high-altitude lakes

    Science.gov (United States)

    SOMMARUGA, RUBEN; CASAMAYOR, EMILIO O.

    2010-01-01

    SUMMARY In October 2004, plankton samples were collected from six permanent lakes located between 4960 and 5440 m a.s.l. in the Mount Everest region (Nepal) to assess how spatial and local environmental factors affect natural bacterial community composition. Fingerprinting analysis of the bacterial 16S rRNA gene fragment was done by denaturing gradient gel electrophoresis (DGGE). The number of DGGE bands (range: 12–23) was not correlated with lake area or remoteness, but there was a strong negative correlation with the ratio of catchment to lake area (r = −0.826, P 98 to 100%) in partial 16S rRNA gene sequence to those reported from other alpine lakes and glaciers around the world, suggesting the presence of ‘cosmopolitan’ bacteria. An analysis based on dissimilarity matrices and the Mantel test revealed the existence of dissimilarities in bacterial community composition related to geographical distance over a small spatial scale (aquatic realm, but taxon sorting by local environmental constraints is important. PMID:20543908

  20. Can dressings soaked with polyhexanide reduce bacterial loads in full-thickness skin grafting? A randomized controlled trial.

    Science.gov (United States)

    Saleh, Karim; Sonesson, Andreas; Persson, Kerstin; Riesbeck, Kristian; Schmidtchen, Artur

    2016-12-01

    Polyhexamethylene biguanide (PHMB)-based antiseptic solutions can reduce bacterial loads in different clinical settings and are believed to lower risk of infections. We sought to assess the efficacy of a PHMB-based solution in lowering bacterial loads of full-thickness skin grafting wounds and the risk of surgical site infections (SSIs). In this double-blinded clinical trial, 40 patients planned for facial full-thickness skin grafting were randomized 1:1 to receive tie-over dressings soaked with either PHMB-based solution or sterile water. Quantitative and qualitative bacterial analysis was performed on all wounds before surgery, at the end of surgery, and 7 days postoperatively. In addition, all patients were screened for nasal colonization of Staphylococcus aureus. Analysis of wounds showed no statistically significant difference in bacterial reductions between the groups. The SSI rates were significantly higher in the intervention group (8/20) than in the control group (2/20) (P = .028). Higher postoperative bacterial loads were a common finding in SSIs (P = .011). This was more frequent when S aureus was present postoperatively (P = .034), intraoperatively (P = .03), and in patients with intranasal S aureus colonization (P = .007). Assessment of SSIs is largely subjective. In addition, this was a single-center study and the total number of participants was 40. Soaking tie-over dressings with PHMB solution in full-thickness skin grafting had no effect on postoperative bacterial loads and increased the risk of SSI development. The presence of S aureus intranasally and in wounds preoperatively and postoperatively increased postoperative bacterial loads, which in turn resulted in significantly more SSIs. Copyright © 2016 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

  1. A full-length group 1 bacterial sigma factor adopts a compact structure incompatible with DNA binding.

    Science.gov (United States)

    Schwartz, Edmund C; Shekhtman, Alexander; Dutta, Kaushik; Pratt, Matthew R; Cowburn, David; Darst, Seth; Muir, Tom W

    2008-10-20

    The sigma factors are the key regulators of bacterial transcription initiation. Through direct read-out of promoter DNA sequence, they recruit the core RNA polymerase to sites of initiation, thereby dictating the RNA polymerase promoter-specificity. The group 1 sigma factors, which direct the vast majority of transcription initiation during log phase growth and are essential for viability, are autoregulated by an N-terminal sequence known as sigma1.1. We report the solution structure of Thermotoga maritima sigmaA sigma1.1. We additionally demonstrate by using chemical crosslinking strategies that sigma1.1 is in close proximity to the promoter recognition domains of sigmaA. We therefore propose that sigma1.1 autoinhibits promoter DNA binding of free sigmaA by stabilizing a compact organization of the sigma factor domains that is unable to bind DNA.

  2. Clinical and Microbiological Features and Factors Associated with Fluoroquinolone Resistance in Men with Community-Acquired Acute Bacterial Prostatitis.

    Science.gov (United States)

    Park, Min Gu; Cho, Min Chul; Cho, Sung Yong; Lee, Jeong Woo

    2016-01-01

    To investigate the clinical and microbiological features in the patients with community-acquired acute bacterial prostatitis (CA-ABP), as well as factors that affect fluoroquinolone resistance. A retrospective analysis was performed of 209 patients hospitalized for antibiotic treatment of CA-ABP. We investigated patient age, body mass index, underlying diseases, recurrence, prostate-related factors and results of urine culture examination and antibiotic sensitivity tests. Seventeen patients (8.1%) had fluoroquinolone-resistant bacterial colonies. When we divided the subjects into groups according to the fluoroquinolone resistance, the group with resistant bacteria was significantly older, had larger prostates and had greater residual urine volumes. Bacteria were identified in 127 of 209 patients (60.8%), and the most commonly cultured included Escherichia coli (43.5%). The sensitivity of the cultured bacteria to fluoroquinolones was high compared to trimethoprim/sulfamethoxazole and gentamicin, but similar to cefotaxime. The bacteria were more sensitive to amikacin and imipenem than to fluoroquinolone. The multivariate analysis revealed that prostate volume ≥40 ml (p = 0.024) and residual urine volume >100 ml (p = 0.004) were independent predictive factors for fluoroquinolone resistance. Fluoroquinolone monotherapy might be an effective treatment in CA-ABP. However, combination antibiotic therapy is recommended in cases with prostate volume ≥40 ml or residual urine volume >100 ml, because fluoroquinolone resistance can occur. © 2016 S. Karger AG, Basel.

  3. Colon cancer controls versus population controls in case-control studies of occupational risk factors

    Directory of Open Access Journals (Sweden)

    Sabroe Svend

    2004-04-01

    Full Text Available Abstract Background Since updated population registers do not exist in many countries it is often difficult to sample valid population controls from the study base to a case-control study. Use of patient controls is an alternative option if the exposure experience under study for these patients are interchangeable with the experience for population controls. Patient controls may even be preferable from population controls under certain conditions. In this study we examine if colon cancer patients can serve as surrogates for proper population controls in case-control studies of occupational risk factors. Methods The study was conducted from 1995 to 1997. Incident colon cancer controls (N = 428 aged 35–69 years with a histological verified diagnosis and population controls (N = 583 were selected. Altogether 254 (59% of the colon cancer controls and 320 (55% of the population controls were interviewed about occupational, medical and life style conditions. Results No statistical significant difference for educational level, medical history or smoking status was seen between the two control groups. There was evidence of a higher alcohol intake, less frequent work as a farmer and less exposure to pesticides among colon cancer controls. Conclusions Use of colon cancer controls may provide valid exposure estimates in studies of many occupational risk factors for cancer, but not for studies on exposure related to farming.

  4. Secretion of a bacterial virulence factor is driven by the folding of a C-terminal segment

    OpenAIRE

    Peterson, Janine H.; Tian, Pu; Ieva, Raffaele; Dautin, Nathalie; Bernstein, Harris D.

    2010-01-01

    Autotransporters are bacterial virulence factors consisting of an N-terminal “passenger domain” that is secreted in a C- to-N-terminal direction and a C-terminal “β domain” that resides in the outer membrane (OM). Although passenger domain secretion does not appear to use ATP, the energy source for this reaction is unknown. Here, we show that efficient secretion of the passenger domain of the Escherichia coli O157:H7 autotransporter EspP requires the stable folding of a C-terminal ≈17-kDa pas...

  5. Invasive Fungal Rhinosinusitis versus Bacterial Rhinosinusitis with Orbital Complications: A Case-Control Study

    Directory of Open Access Journals (Sweden)

    Patorn Piromchai

    2013-01-01

    Full Text Available Background. Invasive fungal rhinosinusitis with orbital complications (IFSwOC is a life-threatening condition. The incidence of mortality has been reported to be up to 80 percent. This study was conducted to determine the risk factors, presentations, clinical, and imaging findings that could help to manage this condition promptly. Methods. We conducted a case-control study of 100 patients suffering from rhinosinusitis with orbital complications. The risk factors, clinical presentations, radiological findings, medical and surgical managements, durations of hospital stay, and mortality rate data were collected. Results. Sixty-five patients were diagnosed with IFSwOC, while the other thirty-five patients composed the control group. The most important risk factor for IFSwOC was diabetes mellitus. Visual loss and diplopia were the significant symptom predictors. The significant clinical predictors were nasal crust, oculomotor nerve, and optic nerve involvement. The CT findings of IFSwOC were sinus wall erosion and hyperdensity lesions. The mortality rate was 25.71 percent in the IFSwOC group and 3.17 percent in the control group. Conclusions. Invasive fungal rhinosinusitis with orbital complications is symptomatic of a high mortality rate. The awareness of a patient’s risk factors, the presenting symptoms, signs of fungal invasion, and aggressive management will determine the success of any treatment procedures.

  6. Controlled extended octenidine release from a bacterial nanocellulose/Poloxamer hybrid system.

    Science.gov (United States)

    Alkhatib, Y; Dewaldt, M; Moritz, S; Nitzsche, R; Kralisch, D; Fischer, D

    2017-03-01

    Although bacterial nanocellulose (BNC) has been widely investigated in the last 10years as drug delivery system, up to now no long-term controlled release of drugs could be realized. Therefore, the aim of the present work was the development of a BNC-based drug delivery system that provides prolonged retention time for the antiseptic octenidine up to one week with improved mechanical and antimicrobial properties as well as a high biocompatibility. BNC was modified by incorporation of differently concentrated Poloxamers 338 and 407 as micelles and gels that were extensively investigated regarding size, surface charge, and dynamic viscosity. Depending on type and concentration of the Poloxamer, a retarded octenidine release up to one week could be accomplished. Additionally, superior material properties such as high compression stability and water binding could be achieved. The antimicrobial activity of octenidine against Staphylococcus aureus and Pseudomonas aeruginosa was not changed by the use of Poloxamers. Excellent biocompatibility of the Poloxamer loaded BNC could be demonstrated after local administration in a shell-less hen's egg model. In conclusion, a long-term delivery system consisting of BNC and Poloxamer could be developed for octenidine as a ready-to-use system e.g. for long-term dermal wound treatment. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. A novel bacterial pathogen of Biomphalaria glabrata: a potential weapon for schistosomiasis control?

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    David Duval

    2015-02-01

    Full Text Available Schistosomiasis is the second-most widespread tropical parasitic disease after malaria. Various research strategies and treatment programs for achieving the objective of eradicating schistosomiasis within a decade have been recommended and supported by the World Health Organization. One of these approaches is based on the control of snail vectors in endemic areas. Previous field studies have shown that competitor or predator introduction can reduce snail numbers, but no systematic investigation has ever been conducted to identify snail microbial pathogens and evaluate their molluscicidal effects.In populations of Biomphalaria glabrata snails experiencing high mortalities, white nodules were visible on snail bodies. Infectious agents were isolated from such nodules. Only one type of bacteria, identified as a new species of Paenibacillus named Candidatus Paenibacillus glabratella, was found, and was shown to be closely related to P. alvei through 16S and Rpob DNA analysis. Histopathological examination showed extensive bacterial infiltration leading to overall tissue disorganization. Exposure of healthy snails to Paenibacillus-infected snails caused massive mortality. Moreover, eggs laid by infected snails were also infected, decreasing hatching but without apparent effects on spawning. Embryonic lethality was correlated with the presence of pathogenic bacteria in eggs.This is the first account of a novel Paenibacillus strain, Ca. Paenibacillus glabratella, as a snail microbial pathogen. Since this strain affects both adult and embryonic stages and causes significant mortality, it may hold promise as a biocontrol agent to limit schistosomiasis transmission in the field.

  8. Transgenic resistance confers effective field level control of bacterial spot disease in tomato.

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    Diana M Horvath

    Full Text Available We investigated whether lines of transgenic tomato (Solanum lycopersicum expressing the Bs2 resistance gene from pepper, a close relative of tomato, demonstrate improved resistance to bacterial spot disease caused by Xanthomonas species in replicated multi-year field trials under commercial type growing conditions. We report that the presence of the Bs2 gene in the highly susceptible VF 36 background reduced disease to extremely low levels, and VF 36-Bs2 plants displayed the lowest disease severity amongst all tomato varieties tested, including commercial and breeding lines with host resistance. Yields of marketable fruit from transgenic lines were typically 2.5 times that of the non-transformed parent line, but varied between 1.5 and 11.5 fold depending on weather conditions and disease pressure. Trials were conducted without application of any copper-based bactericides, presently in wide use despite negative impacts on the environment. This is the first demonstration of effective field resistance in a transgenic genotype based on a plant R gene and provides an opportunity for control of a devastating pathogen while eliminating ineffective copper pesticides.

  9. Optimal hand washing technique to minimize bacterial contamination before neuraxial anesthesia: a randomized control trial.

    Science.gov (United States)

    Siddiqui, N; Friedman, Z; McGeer, A; Yousefzadeh, A; Carvalho, J C; Davies, S

    2017-02-01

    Infectious complications related to neuraxial anesthesia may result in adverse outcomes. There are no best practice guidelines regarding hand-sanitizing measures specifically for these procedures. The objective of this study was to compare the growth of microbial organisms on the operator's forearm between five common techniques of hand washing for labor epidurals. In this single blind randomized controlled trial, all anesthesiologists performing labor epidurals in a tertiary care hospital were randomized into five study groups: hand washing with alcohol gel only up to elbows (Group A); hand washing with soap up to elbows, sterile towel to dry, followed by alcohol gel (Group B); hand washing with soap up to elbows, non-sterile towel to dry, followed by alcohol gel (Group C); hand washing with soap up to elbows, non-sterile towel to dry (Group D) or hand washing with soap up to elbows, sterile towel to dry (Group E). The number of colonies for each specimen/rate per 100 specimens on one or both arms per group was measured. The incidence of colonization was 2.5, 23.0, 18.5, 114.5, and 53.0 in Groups A, B, C, D and E, respectively. Compared to Group A, the odds ratio of bacterial growth for Group B was 1.52 (P=0.519), Group C 5.44 (P=0.003), Group D 13.82 (Phand-sanitizing practices among epidural practitioners. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. 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.

  11. Lower Circulating Levels of Chemokine CXCL10 In Helicobacter Pylori-Infected Patients with Peptic Ulcer: Influence of the Bacterial Virulence Factor CagA

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    Abdollah Jafarzadeh

    2013-03-01

    Full Text Available Background and objectives: Alterations in CXCL10 (a Th1 chemokine expression have been associated with various diseases. The aim of this study was to evaluate the serum CXCL10 levels in H. pylori-infected patients with peptic ulcer (PU and to determine its association with bacterial virulence factor cytotoxin-associated gene A (CagA. Materials and Methods: Serum samples from 90 H. pylori infected patients (70 were anti-CagA+, 20 were anti-CagA-, 65 asymptomatic (AS carriers (40 were anti-CagA+, 25 were anti-CagA- and 30 healthy H. pylori-negative subjects (as a control were tested for the concentrations of CXCL10 by using ELISA method. Results: The mean serum levels of CXCL10 in PU patients (96.64 ± 20.85 Pg/mL was significantly lower than those observed in AS subjects (162.16 ± 53.31 Pg/mL, P < 0.01 and control group (193.93 ± 42.14 Pg/mL, P < 0.02. In the PU group, the levels of CXCL10 in anti-CagA+ subjects was significantly higher in comparison to anti-CagA- patients (P<0.04. Conclusion: These results showed that the mean concentrations of CXCL10 in H. pylori-infected-PU patients was lower than AS carriers and control group. In the PU group, the serum levels of CXCL10 were affected by bacterial factor CagA.

  12. Influenza-associated bacterial pneumonia; managing and controlling infection on two fronts.

    Science.gov (United States)

    Campigotto, Aaron; Mubareka, Samira

    2015-01-01

    Bacterial pneumonia complicating influenza is well-recognized as a severe manifestation of influenza, accounting for a substantial number of deaths from the 1918 influenza pandemic. Influenza-associated bacterial pneumonia remains a major contributor to the burden of influenza, and poses new challenges as antibiotic-resistant organisms such as methicillin-resistant Staphylococcus aureus spread. We provide an overview of the current state of knowledge of the epidemiology and co-pathogenesis of influenza-associated bacterial pneumonia, and outline management approaches and their limitations. We review preventative measures and discuss implications for pandemic planning. Knowledge gaps are underscored and future research directions are proposed.

  13. [Characterization of a bacterial biocontrol strain 1404 and its efficacy in controlling postharvest citrus anthracnose].

    Science.gov (United States)

    Wang, Qian; Hu, Chunjin; Ke, Fanggang; Huang, Siliang; Li, Qiqin

    2010-09-01

    Anthracnose caused by Colletotrichum gloeosporioides (Penz.) Sacc. is a main disease in citrus production. To develop an effective biocontrol measure against citrus postharvest anthracnose, we screened antagonistic microbes and obtained a bacterial strain 1404 from the rhizospheric soil of chili plants in Nanning city, Guangxi, China. The objectives of the present study were to: (1) identify and characterize the antagonistic bacterium; and (2) to evaluate the efficacy of the antagonistic strain in controlling citrus postharvest anthracnose disease. Strain 1404 was identified by comparing its 16S rDNA sequence with related bacteria from GenBank database, as well as analyzing its morphological, physiological and biochemical characters. The antagonistic stability of the strain 1404 was determined by continuously transferring it on artificial media. The effect of the strain on suppressing citrus anthracnose at postharvest stage was tested by stab inoculation method. The 16S rDNA of strain 1404 was amplified with primers PF1 (5'-AGAGTTTGATCATGGCTCAG-3') and PR1 (5'-TACGGTTACCTTGTTACGACTT-3') and its sequence submitted to GenBank (accession number: GU361113). Strain 1404 clustered with the GenBank-derived Brevibacillus brevis strains in the 16S-rDNA-sequence-based phylogenetic tree at 100% bootstrap level. The morphological traits, physiological and biochemical characters of strain 1404 agreed with that of Brevibacillus brevis. Less change in the suppressive ability of antagonist against growth of Colletotrichum gloeosporioides was observed during four continuous transfers on artificial media. The average control efficacy of the strain was 64. 9 % against the disease 20 days after the antagonist application. Strain 1404 was identified as Brevibacillus brevis based on its morphological traits, phyiological and biochemical characters as well as 16S rDNA sequence analysis. The antagonist was approved to be a promising biocontrol agent. This is the first report of

  14. Bacterial quorum sensing: its role in virulence and possibilities for its control.

    Science.gov (United States)

    Rutherford, Steven T; Bassler, Bonnie L

    2012-11-01

    Quorum sensing is a process of cell-cell communication that allows bacteria to share information about cell density and adjust gene expression accordingly. This process enables bacteria to express energetically expensive processes as a collective only when the impact of those processes on the environment or on a host will be maximized. Among the many traits controlled by quorum sensing is the expression of virulence factors by pathogenic bacteria. Here we review the quorum-sensing circuits of Staphylococcus aureus, Bacillus cereus, Pseudomonas aeruginosa, and Vibrio cholerae. We outline these canonical quorum-sensing mechanisms and how each uniquely controls virulence factor production. Additionally, we examine recent efforts to inhibit quorum sensing in these pathogens with the goal of designing novel antimicrobial therapeutics.

  15. THE ROLE OF BACTERIAL FACTOR AND IMMUNOLOGICAL СHANGES IN NONINFECTIOUS DISEASES OF MICROBIAL ORIGIN

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    Korniychuk O.P.

    2015-05-01

    Full Text Available Introduction. Today during the study of the development mechanisms of any somatic disease possible participation of the microorganism as trigger factor or its influence on the course of the disease or development of complications is considered. Microflora participation in the etiopathogenesis of noninfectious diseases allows to divide the latest into the following groups: Naturally, the first aspects of the study of the role of microorganisms in the development of noninfectious diseases are pathological processes developing in the organs and systems of the body, which are natural biotope, particularly gastrointestinal tract. The imbalance in the functioning of the macroorganism (stress, poor diet causes changes in the composition of endogenous microcenosis and therefore dysbiosis. Thus changes in the hormonal homeostasis, immunoreactivity, in the hypothalamic-adrenal system, speed of peristalsis of the intestines are observed, the overgrowth syndrome in the small intestine developes. A classic disease of a group of diseases that are accompanied by the development of erosive conditions are Helicobacter pylori - associated ulcerous disease of 12 duodenal ulcer. Diseases of the colon digestive canal can be divided into 2 groups - ulcerative colitis and tumors. Escherichia are the main representatives of facultative anaerobic microflora of the colon and are involved in the pathogenesis of both ulcerative colitis and cancer. Material and methods. A study in order to compare the inducing impact of Escherichia lipopolysaccharide isolated from patients with nonspecific ulcerative colitis (NUC, N =38, Crohn's disease (CD, N =30 and colon cancer (CC, N =38, on the humoral and cellular (cytokine links of immunity in ulcerative colitis and colon cancer. From the patients in both study groups and individuals from the control group E. coli were isolated from fecal for obtainining LPS. Synthesis induction of TNFα, IL.-8 and IL.-10 was conducted by

  16. Broad-spectrum antibiotic or G-CSF as potential countermeasures for impaired control of bacterial infection associated with an SPE exposure during spaceflight.

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    Minghong Li

    Full Text Available A major risk for astronauts during prolonged space flight is infection as a result of the combined effects of microgravity, situational and confinement stress, alterations in food intake, altered circadian rhythm, and radiation that can significantly impair the immune system and the body's defense systems. We previously reported a massive increase in morbidity with a decrease in the ability to control a bacterial challenge when mice were maintained under hindlimb suspension (HS conditions and exposed to solar particle event (SPE-like radiation. HS and SPE-like radiation treatment alone resulted in a borderline significant increase in morbidity. Therefore, development and testing of countermeasures that can be used during extended space missions in the setting of exposure to SPE radiation becomes a serious need. In the present study, we investigated the efficacy of enrofloxacin (an orally bioavailable antibiotic and Granulocyte colony stimulating factor (G-CSF (Neulasta on enhancing resistance to Pseudomonas aeruginosa infection in mice subjected to HS and SPE-like radiation. The results revealed that treatment with enrofloxacin or G-CSF enhanced bacterial clearance and significantly decreased morbidity and mortality in challenged mice exposed to suspension and radiation. These results establish that antibiotics, such as enrofloxacin, and G-CSF could be effective countermeasures to decrease the risk of bacterial infections after exposure to SPE radiation during extended space flight, thereby reducing both the risk to the crew and the danger of mission failure.

  17. Short communication: bulk tank total bacterial count in dairy sheep: factors of variation and relationship with somatic cell count.

    Science.gov (United States)

    Gonzalo, C; Carriedo, J A; Beneitez, E; Juárez, M T; De La Fuente, L F; San Primitivo, F

    2006-02-01

    A total of 9,353 records for bulk tank total bacterial count (TBC) were obtained over 1 yr from 315 dairy ewe flocks belonging to the Sheep Improvement Consortium (CPO) in Castilla-León (Spain). Analysis of variance showed significant effects of flock, breed, month within flock, dry therapy, milking type and installation, and logSCC on logTBC. Flock and month within flock were important variation factors as they accounted for 22.0 and 22.1% of the variance, respectively. Considerable repeatability values were obtained for both random factors. Hand milking and bucket-milking machines elicited highest logTBC (5.31), whereas parlor systems with looped milkline (5.01) elicited the lowest logTBC. The implementation of dry therapy practice (5.12) showed significantly lower logTBC than when not used (5.25). Variability in logTBC among breeds ranged from 5.24 (Awassi) to 5.07 (Churra). However, clinical outbreaks of contagious agalactia did not increase TBC significantly. A statistically significant relationship was found between logTBC and logSCC, the correlation coefficient between the variables being r = 0.23. Programs for improving milk hygiene should be implemented for both total bacterial count and somatic cell count variables at the same time.

  18. Resource availability and spatial heterogeneity control bacterial community response to nutrient enrichment in lakes.

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    Kathijo Jankowski

    Full Text Available The diversity and composition of ecological communities often co-vary with ecosystem productivity. However, the relative importance of productivity, or resource abundance, versus the spatial distribution of resources in shaping those ecological patterns is not well understood, particularly for the bacterial communities that underlie most important ecosystem functions. Increasing ecosystem productivity in lakes has been shown to influence the composition and ecology of bacterial communities, but existing work has only evaluated the effect of increasing resource supply and not heterogeneity in how those resources are distributed. We quantified how bacterial communities varied with the trophic status of lakes and whether community responses differed in surface and deep habitats in response to heterogeneity in nutrient resources. Using ARISA fingerprinting, we found that bacterial communities were more abundant, richer, and more distinct among habitats as lake trophic state and vertical heterogeneity in nutrients increased, and that spatial resource variation produced habitat specific responses of bacteria in response to increased productivity. Furthermore, changes in communities in high nutrient lakes were not produced by turnover in community composition but from additional taxa augmenting core bacterial communities found in lower productivity lakes. These data suggests that bacterial community responses to nutrient enrichment in lakes vary spatially and are likely influenced disproportionately by rare taxa.

  19. Comparative usefulness of inflammatory markers to indicate bacterial infection-analyzed according to blood culture results and related clinical factors.

    Science.gov (United States)

    Nishikawa, Hirokazu; Shirano, Michinori; Kasamatsu, Yu; Morimura, Ayumi; Iida, Ko; Kishi, Tomomi; Goto, Tetsushi; Okamoto, Saki; Ehara, Eiji

    2016-01-01

    To assess relationships of inflammatory markers and 2 related clinical factors with blood culture results, we retrospectively investigated inpatients' blood culture and blood chemistry findings that were recorded from January to December 2014 using electronic medical records and analyzed the data of 852 subjects (426 culture-positive and 426 culture-negative). Results suggested that the risk of positive blood culture statistically increased as inflammatory marker levels and the number of related factors increased. Concerning the effectiveness of inflammatory markers, when the outcome definition was also changed for C-reactive protein (CRP), the odds ratio had a similar value, whereas when the outcome definition of blood culture positivity was used for procalcitonin (PCT), the greatest effectiveness of that was detected. Therefore, the current results suggest that PCT is more useful than CRP as an auxiliary indication of bacterial infection.

  20. Characterizing the interplay between multiple levels of organization within bacterial sigma factor regulatory networks.

    Science.gov (United States)

    Qiu, Yu; Nagarajan, Harish; Embree, Mallory; Shieu, Wendy; Abate, Elisa; Juárez, Katy; Cho, Byung-Kwan; Elkins, James G; Nevin, Kelly P; Barrett, Christian L; Lovley, Derek R; Palsson, Bernhard O; Zengler, Karsten

    2013-01-01

    Bacteria contain multiple sigma factors, each targeting diverse, but often overlapping sets of promoters, thereby forming a complex network. The layout and deployment of such a sigma factor network directly impacts global transcriptional regulation and ultimately dictates the phenotype. Here we integrate multi-omic data sets to determine the topology, the operational, and functional states of the sigma factor network in Geobacter sulfurreducens, revealing a unique network topology of interacting sigma factors. Analysis of the operational state of the sigma factor network shows a highly modular structure with σ(N) being the major regulator of energy metabolism. Surprisingly, the functional state of the network during the two most divergent growth conditions is nearly static, with sigma factor binding profiles almost invariant to environmental stimuli. This first comprehensive elucidation of the interplay between different levels of the sigma factor network organization is fundamental to characterize transcriptional regulatory mechanisms in bacteria.

  1. Characterizing the interplay betwen mulitple levels of organization within bacterial sigma factor regulatory networks

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Qiu [University of California, San Diego; Nagarajan, Harish [University of California, San Diego; Embree, Mallory [University of California, San Diego; Shieu, Wendy [University of California, San Diego; Abate, Elisa [University of California, San Diego; Juarez, Katy [Universidad Nacional Autonoma de Mexico (UNAM); Cho, Byung-Kwan [University of California, San Diego; Elkins, James G [ORNL; Nevin, Kelly P. [University of Massachusetts, Amherst; Barrett, Christian [University of California, San Diego; Lovley, Derek [University of Massachusetts, Amherst; Palsson, Bernhard O. [University of California, San Diego; Zengler, Karsten [University of California, San Diego

    2013-01-01

    Bacteria contain multiple sigma factors, each targeting diverse, but often overlapping sets of promoters, thereby forming a complex network. The layout and deployment of such a sigma factor network directly impacts global transcriptional regulation and ultimately dictates the phenotype. Here we integrate multi-omic data sets to determine the topology, the operational, and functional states of the sigma factor network in Geobacter sulfurreducens, revealing a unique network topology of interacting sigma factors. Analysis of the operational state of the sigma factor network shows a highly modular structure with sN being the major regulator of energy metabolism. Surprisingly, the functional state of the network during the two most divergent growth conditions is nearly static, with sigma factor binding profiles almost invariant to environmental stimuli. This first comprehensive elucidation of the interplay between different levels of the sigma factor network organization is fundamental to characterize transcriptional regulatory mechanisms in bacteria.

  2. Various factors affecting the bacterial corneal ulcer healing: a 4-years study in referral tertiary eye hospital in Indonesia

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    Muhammad Asroruddin

    2015-11-01

    Full Text Available Background: Corneal ulcer is one of the most common causes of visual acuity impairment and blindness all over the world. The aim of the study was to evaluate various factors affecting the bacterial corneal ulcers healing, including the predisposing factors, causative organisms, antibiotic sensitivity, as well as the treatment outcomes.Methods: All data were taken retrospectively from medical records of patients who underwent corneal scraping for Gram examination and/or culture over a-4-year period (2008-2011 at the Cipto Mangunkusumo Hospital Jakarta. Treatment outcome were analyzed using Chi-square test, one-way ANOVA, and post-hoc analysis. Mean time required for complete epithelial healing was also investigated.Results: 220 cases of bacterial corneal ulcers in 216 patients were included. The most common risk factors were ocular trauma (45.8%. Gram-positive coccus were found in 65.7% cases other than other microbes. Pseudomonas sp. (25,0% and Staphylococcus epidermidis (18.4% were the most common isolates, sensitive to almost all kinds of antibiotics. About 83.0% (106 cases were improved with antibiotics only, the rest were not improved and worsened. Mean time for complete epithelial healing was 17.5 ± 8.9 days with mild ulcer had the most rapid recovery. Eyes treated with fluoroquinolone eyedrops were healed in 14 days, faster than other regiments.Conclusion: Ocular trauma was the most common risk factor for corneal ulcer, and the most commonly isolated organism was Pseudomonas sp. Most cases were improved with antibiotics, and fluoroquinolone showed faster healing. Complete epithelial healing occurred in about 17.5 days.

  3. 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

  4. A bacterial cytotoxin identifies the RhoA exchange factor Net1 as a key effector in the response to DNA damage.

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    Lina Guerra

    Full Text Available BACKGROUND: Exposure of adherent cells to DNA damaging agents, such as the bacterial cytolethal distending toxin (CDT or ionizing radiations (IR, activates the small GTPase RhoA, which promotes the formation of actin stress fibers and delays cell death. The signalling intermediates that regulate RhoA activation and promote cell survival are unknown. PRINCIPAL FINDINGS: We demonstrate that the nuclear RhoA-specific Guanine nucleotide Exchange Factor (GEF Net1 becomes dephosphorylated at a critical inhibitory site in cells exposed to CDT or IR. Expression of a dominant negative Net1 or Net1 knock down by iRNA prevented RhoA activation, inhibited the formation of stress fibers, and enhanced cell death, indicating that Net1 activation is required for this RhoA-mediated responses to genotoxic stress. The Net1 and RhoA-dependent signals involved activation of the Mitogen-Activated Protein Kinase p38 and its downstream target MAPK-activated protein kinase 2. SIGNIFICANCE: Our data highlight the importance of Net1 in controlling RhoA and p38 MAPK mediated cell survival in cells exposed to DNA damaging agents and illustrate a molecular pathway whereby chronic exposure to a bacterial toxin may promote genomic instability.

  5. Power factor control system for ac induction motors

    Science.gov (United States)

    Nola, F. J. (Inventor)

    1981-01-01

    A power control circuit for an induction motor is disclosed in which a servo loop is used to control power input by controlling the power factor of motor operation. The power factor is measured by summing the voltage and current derived square wave signals.

  6. Control of bacterial contamination in microfiltered water dispensers (MWDs) by disinfection.

    Science.gov (United States)

    Zanetti, Franca; De Luca, Giovanna; Sacchetti, Rossella

    2009-01-15

    Three microfiltered water dispensers (MWDs) for domestic use were bacteriologically monitored over a period of 1 year to evaluate their hygienic status and to compare the ability of two disinfectants (peracetic acid and hydrogen peroxide) to ensure adequate bacteriological quality of the dispensed water. To this end, two dispensers were purposely contaminated with a strain of Pseudomonas aeruginosa of environmental origin. A total of 324 samples of input and output water were analyzed. Heterotrophic plate count (HPC) bacteria at 22 degrees C and 36 degrees C, total coliforms (CT), Escherichia coli (EC), enterococci (ENT), P. aeruginosa and Staphylococcus aureus were enumerated. Throughout the study period, the supply water was always of excellent bacteriological quality. All water samples taken from the MWDs complied with the legal requirements for drinking water: CT, EC, ENT and S. aureus were all consistently absent. P. aeruginosa was never isolated from the uncontaminated dispenser. However, an increase in HPCs up to levels of 10(3)-10(4) cfu/mL was found in the dispensed water. Under the present operative conditions, hydrogen peroxide was seen to be more effective than peracetic acid in controlling bacterial contamination in the water circuits. Periodic disinfection with hydrogen peroxide made it possible to obtain water with HPC levels conforming to Italian regulations for drinking water (disinfection led to a reduction in the concentrations of P. aeruginosa to only a few colony forming units/100 mL or to a complete, albeit temporary, disappearance of the microorganism. In conclusion, hydrogen peroxide at 3% can be proposed as a suitable product for periodic disinfection of domestic MWDs, taking into consideration also its low cost and easy availability.

  7. Diaphragm Used with Replens Gel and Risk of Bacterial Vaginosis: Results from a Randomized Controlled Trial

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    Craig R. Cohen

    2012-01-01

    Full Text Available Background. Bacterial vaginosis (BV has been linked to female HIV acquisition and transmission. We investigated the effect of providing a latex diaphragm with Replens and condoms compared to condom only on BV prevalence among participants enrolled in an HIV prevention trial. Methods. We enrolled HIV-seronegative women and obtained a vaginal swab for diagnosis of BV using Nugent’s criteria; women with BV (score 7–10 were compared to those with intermediate (score 4–6 and normal flora (score 0–3. During quarterly follow-up visits over 12–24 months a vaginal Gram stain was obtained. The primary outcome was serial point prevalence of BV during followup. Results. 528 participants were enrolled; 213 (40% had BV at enrollment. Overall, BV prevalence declined after enrollment in women with BV at baseline (OR=0.4, 95% CI 0.29–.56 but did not differ by intervention group. In the intention-to-treat analysis BV prevalence did not differ between the intervention and control groups for women who had BV (OR=1.01, 95% CI 0.52–1.94 or for those who did not have BV (OR=1.21, 95% CI 0.65–2.27 at enrollment. Only 2.1% of participants were treated for symptomatic BV and few women (5–16% were reported using anything else but water to cleanse the vagina over the course of the trial. Conclusions. Provision of the diaphragm, Replens, and condoms did not change the risk of BV in comparison to the provision of condoms alone.

  8. Prevalence and Risk Factors for Bacterial Vaginosis and Other Vulvovaginitis in a Population of Sexually Active Adolescents from Salvador, Bahia, Brazil

    OpenAIRE

    Rita Elizabeth Moreira Mascarenhas; Márcia Sacramento Cunha Machado; Bruno Fernando Borges da Costa e Silva; Rodrigo Fernandes Weyll Pimentel; Tatiana Teixeira Ferreira; Fernanda Maria Silva Leoni; Maria Fernanda Rios Grassi

    2012-01-01

    Bacterial vaginosis, trichomoniasis, and genital candidiasis are considered the main etiologies of vulvovaginitis. Few studies estimate the prevalence of vulvovaginitis among adolescents, especially in Brazil. This study aimed to determine the prevalence and main risk factors associated with bacterial vaginosis and genital infection by C. albicans and Trichomonas vaginalis among a group of adolescents from Salvador, Bahia, Brazil. One hundred sexually active adolescents followed at an adolesc...

  9. Prevalence and Risk Factors for Bacterial Vaginosis and Other Vulvovaginitis in a Population of Sexually Active Adolescents from Salvador, Bahia, Brazil

    OpenAIRE

    Rita Elizabeth Moreira Mascarenhas; Márcia Sacramento Cunha Machado; Bruno Fernando Borges da Costa e Silva; Rodrigo Fernandes Weyll Pimentel; Tatiana Teixeira Ferreira; Fernanda Maria Silva Leoni; Maria Fernanda Rios Grassi

    2012-01-01

    Bacterial vaginosis, trichomoniasis, and genital candidiasis are considered the main etiologies of vulvovaginitis. Few studies estimate the prevalence of vulvovaginitis among adolescents, especially in Brazil. This study aimed to determine the prevalence and main risk factors associated with bacterial vaginosis and genital infection by C. albicans and Trichomonas vaginalis among a group of adolescents from Salvador, Bahia, Brazil. One hundred sexually active adolescents followed at an adolesc...

  10. Engineering control of bacterial cellulose production using a genetic toolkit and a new cellulose-producing strain.

    Science.gov (United States)

    Florea, Michael; Hagemann, Henrik; Santosa, Gabriella; Abbott, James; Micklem, Chris N; Spencer-Milnes, Xenia; de Arroyo Garcia, Laura; Paschou, Despoina; Lazenbatt, Christopher; Kong, Deze; Chughtai, Haroon; Jensen, Kirsten; Freemont, Paul S; Kitney, Richard; Reeve, Benjamin; Ellis, Tom

    2016-06-14

    Bacterial cellulose is a strong and ultrapure form of cellulose produced naturally by several species of the Acetobacteraceae Its high strength, purity, and biocompatibility make it of great interest to materials science; however, precise control of its biosynthesis has remained a challenge for biotechnology. Here we isolate a strain of Komagataeibacter rhaeticus (K. rhaeticus iGEM) that can produce cellulose at high yields, grow in low-nitrogen conditions, and is highly resistant to toxic chemicals. We achieved external control over its bacterial cellulose production through development of a modular genetic toolkit that enables rational reprogramming of the cell. To further its use as an organism for biotechnology, we sequenced its genome and demonstrate genetic circuits that enable functionalization and patterning of heterologous gene expression within the cellulose matrix. This work lays the foundations for using genetic engineering to produce cellulose-based materials, with numerous applications in basic science, materials engineering, and biotechnology.

  11. Underlying Factors for Practicality of the Production Control Systems

    DEFF Research Database (Denmark)

    Arica, Emrah; Strandhagen, Jan Ola; Hvolby, Hans-Henrik

    2012-01-01

    This paper gives indications to important factors that must be considered for effectiveness of the production control systems under uncertainty. Five key factors have been identified by the literature study. Production schedule generation and execution approach under uncertainty, information...

  12. Possible interaction between the bacterial transcription factor ArtA and the eukaryotic RNA polymerase III promoter.

    Science.gov (United States)

    Matsutani, Sachiko

    2016-06-01

    Eukaryotic RNA polymerase III (RNAP III) transcribes tRNA genes and short interspersed elements that have internal promoters consisting of A- and B-blocks. The B-block binding subunit of the transcription initiation factor TFIIIC binds to the B-block. The mobile bacterial insertion sequence (IS) 1 contains a RNAP III promoter-like sequence, which stimulates bacterial transcription along with the bacterial ArtA protein. Here, the DNA-binding ability of ArtA was examined in vitro using a simple, newly developed method. Various DNA fragments, including RNAP III promoter fragments, were separately incubated with purified ArtA, and then loaded onto a polyacrylamide gel. Since DNAs bound by ArtA remain in the gel wells during electrophoresis, SDS was added into the wells at the electrophoresis halfway point. It was hypothesized that SDS would dissociate the DNA-ArtA complexes in the wells, and then the DNAs would begin to migrate. In fact, new bands appeared in all of the lanes at similar intensities, indicating that ArtA binds nonspecifically to DNA. Therefore, labeled wild-type RNAP III promoter fragments were incubated with either the unlabeled wild-type or mutant fragments and ArtA, and electrophoresed. The B-block(-like) sequences of IS1, a human Alu element, and an anuran tRNA gene were important for binding to ArtA. Additionally, in silico analyses revealed the presence of the RNAP III promoter-like structures in the IS1 isoforms and the IS3 family elements. These results suggest the presence of parts of the RNAP III transcription machinery in bacteria, and might imply that its prototype existed in the common ancestor.

  13. Top-down controls on bacterial community structure: microbial network analysis of bacteria, T4-like viruses and protists.

    Science.gov (United States)

    Chow, Cheryl-Emiliane T; Kim, Diane Y; Sachdeva, Rohan; Caron, David A; Fuhrman, Jed A

    2014-04-01

    Characterizing ecological relationships between viruses, bacteria and protists in the ocean are critical to understanding ecosystem function, yet these relationships are infrequently investigated together. We evaluated these relationships through microbial association network analysis of samples collected approximately monthly from March 2008 to January 2011 in the surface ocean (0-5 m) at the San Pedro Ocean Time series station. Bacterial, T4-like myoviral and protistan communities were described by Automated Ribosomal Intergenic Spacer Analysis and terminal restriction fragment length polymorphism of the gene encoding the major capsid protein (g23) and 18S ribosomal DNA, respectively. Concurrent shifts in community structure suggested similar timing of responses to environmental and biological parameters. We linked T4-like myoviral, bacterial and protistan operational taxonomic units by local similarity correlations, which were then visualized as association networks. Network links (correlations) potentially represent synergistic and antagonistic relationships such as viral lysis, grazing, competition or other interactions. We found that virus-bacteria relationships were more cross-linked than protist-bacteria relationships, suggestive of increased taxonomic specificity in virus-bacteria relationships. We also found that 80% of bacterial-protist and 74% of bacterial-viral correlations were positive, with the latter suggesting that at monthly and seasonal timescales, viruses may be following their hosts more often than controlling host abundance.

  14. Association between skin diseases and severe bacterial infections in children: case-control study

    Science.gov (United States)

    Mohammedamin, Robbert SA; van der Wouden, Johannes C; Koning, Sander; Willemsen, Sten P; Bernsen, Roos MD; Schellevis, François G; van Suijlekom-Smit, Lisette WA; Koes, Bart W

    2006-01-01

    Background Sepsis or bacteraemia, however rare, is a significant cause of high mortality and serious complications in children. In previous studies skin disease or skin infections were reported as risk factor. We hypothesize that children with sepsis or bacteraemia more often presented with skin diseases to the general practitioner (GP) than other children. If our hypothesis is true the GP could reduce the risk of sepsis or bacteraemia by managing skin diseases appropriately. Methods We performed a case-control study using data of children aged 0–17 years of the second Dutch national survey of general practice (2001) and the National Medical Registration of all hospital admissions in the Netherlands. Cases were defined as children who were hospitalized for sepsis or bacteraemia. We selected two control groups by matching each case with six controls. The first control group was randomly selected from the GP patient lists irrespective of hospital admission and GP consultation. The second control group was randomly sampled from those children who were hospitalized for other reasons than sepsis or bacteraemia. We calculated odds ratios and 95% confidence intervals (CI). A two-sided p-value less than 0.05 was considered significant in all tests. Results We found odds ratios for skin related GP consultations of 3.4 (95% CI: [1.1–10.8], p = 0.03) in cases versus GP controls and 1.4 (95% CI: [0.5–3.9], p = 0.44) in cases versus hospital controls. Children younger than three months had an odds ratio (cases/GP controls) of 9.2 (95% CI: [0.81–106.1], p = 0.07) and 4.0 (95% CI: [0.67–23.9], p = 0.12) among cases versus hospital controls. Although cases consulted the GP more often with skin diseases than their controls, the probability of a GP consultation for skin disease was only 5% among cases. Conclusion There is evidence that children who were admitted due to sepsis or bacteraemia consulted the GP more often for skin diseases than other children, but the

  15. Association between skin diseases and severe bacterial infections in children: case-control study

    Directory of Open Access Journals (Sweden)

    van Suijlekom-Smit Lisette WA

    2006-08-01

    Full Text Available Abstract Background Sepsis or bacteraemia, however rare, is a significant cause of high mortality and serious complications in children. In previous studies skin disease or skin infections were reported as risk factor. We hypothesize that children with sepsis or bacteraemia more often presented with skin diseases to the general practitioner (GP than other children. If our hypothesis is true the GP could reduce the risk of sepsis or bacteraemia by managing skin diseases appropriately. Methods We performed a case-control study using data of children aged 0–17 years of the second Dutch national survey of general practice (2001 and the National Medical Registration of all hospital admissions in the Netherlands. Cases were defined as children who were hospitalized for sepsis or bacteraemia. We selected two control groups by matching each case with six controls. The first control group was randomly selected from the GP patient lists irrespective of hospital admission and GP consultation. The second control group was randomly sampled from those children who were hospitalized for other reasons than sepsis or bacteraemia. We calculated odds ratios and 95% confidence intervals (CI. A two-sided p-value less than 0.05 was considered significant in all tests. Results We found odds ratios for skin related GP consultations of 3.4 (95% CI: [1.1–10.8], p = 0.03 in cases versus GP controls and 1.4 (95% CI: [0.5–3.9], p = 0.44 in cases versus hospital controls. Children younger than three months had an odds ratio (cases/GP controls of 9.2 (95% CI: [0.81–106.1], p = 0.07 and 4.0 (95% CI: [0.67–23.9], p = 0.12 among cases versus hospital controls. Although cases consulted the GP more often with skin diseases than their controls, the probability of a GP consultation for skin disease was only 5% among cases. Conclusion There is evidence that children who were admitted due to sepsis or bacteraemia consulted the GP more often for skin diseases than other

  16. Finite-size effects on bacterial population expansion under controlled fow conditions

    CERN Document Server

    Tesser, Francesca; Clercx, Herman J H; Brunsveld, Luc; Toschi, Federico

    2016-01-01

    The expansion of biological species in natural environments is usually described as the combined effect of individual spatial dispersal and growth. In the case of aquatic ecosystems flow transport can also be extremely relevant as an extra, advection induced, dispersal factor. There is a lack of reproducible experimental studies on biological fronts of living organisms in controlled streaming habitats. It is thus not clear if, and to which extent, the current theoretical and experimental knowledge on advective-reactive-diffusive fronts for chemical reactions can also apply to the expansion of biological populations. We designed and assembled a dedicated microfluidic device to control and quantify the expansion of populations of $E.coli$ bacteria under both co-flowing and counter-flowing conditions, measuring the front speed at varying intensity of the imposed flow. At variance with respect to the case of autocatalytic reactions, we measure that almost irrespective of the counter-flow velocity, the front speed...

  17. Controls on stable sulfur isotope fractionation during bacterial sulfate reduction in Arctic sediments

    DEFF Research Database (Denmark)

    Bruchert, V.; Knoblauch, C.; Jørgensen, BB

    2001-01-01

    Sulfur isotope fractionation experiments during bacterial sulfate reduction were performed with recently isolated strains of cold-adapted sulfate-reducing bacteria from Arctic marine sediments with year-round temperatures below 2 degreesC. The bacteria represent quantitatively important members...... parts per thousand and 8 parts per thousand above 25 degreesC, respectively. In absence of significant differences in sulfate reduction rates in the high and low temperature range, respectively, we infer that different genera of sulfate-reducing bacteria dominate the sulfate-reducing bacterial community...

  18. Phenotypic resistance and the dynamics of bacterial escape from phage control

    DEFF Research Database (Denmark)

    Bull, James J.; Vegge, Christina Skovgaard; Schmerer, Matthew

    2014-01-01

    The canonical view of phage - bacterial interactions in dense, liquid cultures is that the phage will eliminate most of the sensitive cells; genetic resistance will then ascend to restore high bacterial densities. Yet there are various mechanisms by which bacteria may remain sensitive to phages...... mathematical models of these processes and suggest how different types of this 'phenotypic' resistance may be elucidated. We offer preliminary in vitro studies of a previously characterized E. coli model system and Campylobacter jejuni illustrating apparent phenotypic resistance. As phenotypic resistance may...

  19. Uranium isotopic fractionation factors during U(VI) reduction by bacterial isolates

    Science.gov (United States)

    Basu, Anirban; Sanford, Robert A.; Johnson, Thomas M.; Lundstrom, Craig C.; Löffler, Frank E.

    2014-07-01

    We experimentally determined the magnitude of uranium isotopic fractionation induced by U(VI) reduction by metal reducing bacterial isolates. Our results indicate that microbial U(VI) reduction induces isotopic fractionation; heavier isotopes (i.e., 238U) partition into the solid U(IV) products. The magnitudes of isotopic fractionation (expressed as ε = 1000‰ * (α-1)) for 238U/235U were 0.68‰ ± 0.05‰ and 0.99‰ ± 0.12‰ for Geobacter sulfurreducens strain PCA and strain IFRC-N, respectively. The ε values for Anaeromyxobacter dehalogenans strain FRC-W, strain FRC-R5, a novel Shewanella isolate, and Desulfitobacterium sp. strain Viet1 were 0.72‰ ± 0.15‰, 0.99‰ ± 0.12‰, 0.96‰ ± 0.16‰ and 0.86‰ ± 0.06‰, respectively. Our results show that the maximum ε values of ∼1.0‰ were obtained with low biomass (∼107 cells/mL) and low electron donor concentrations (∼500 μM). These results provide an initial assessment of 238U/235U shifts induced by microbially-mediated U(VI) reduction, which is needed as 238U/235U data are increasingly applied as redox indicators in various geochemical settings.

  20. Aptamers to the sigma factor mimic promoter recognition and inhibit transcription initiation by bacterial RNA polymerase.

    Science.gov (United States)

    Miropolskaya, Nataliya; Kulbachinskiy, Andrey

    2016-01-08

    Promoter recognition by bacterial RNA polymerase (RNAP) is a multi-step process involving multiple protein-DNA interactions and several structural and kinetic intermediates which remain only partially characterized. We used single-stranded DNA aptamers containing specific promoter motifs to probe the interactions of the Thermus aquaticus RNAP σ(A) subunit with the -10 promoter element in the absence of other parts of the promoter complex. The aptamer binding decreased intrinsic fluorescence of the σ subunit, likely as a result of interactions between the -10 element and conserved tryptophan residues of the σ DNA-binding region 2. By monitoring these changes, we demonstrated that DNA binding proceeds through a single rate-limiting step resulting in formation of very stable complexes. Deletion of the N-terminal domain of the σ(A) subunit increased the rate of aptamer binding while replacement of this domain with an unrelated N-terminal region 1.1 from the Escherichia coli σ(70) subunit restored the original kinetics of σ-aptamer interactions. The results demonstrate that the key step in promoter recognition can be modelled in a simple σ-aptamer system and reveal that highly divergent N-terminal domains similarly modulate the DNA-binding properties of the σ subunit. The aptamers efficiently suppressed promoter-dependent transcription initiation by the holoenzyme of RNA polymerase, suggesting that they may be used for development of novel transcription inhibitors.

  1. Risk factors and clinical outcomes of bacterial and fungal scleritis at a tertiary eye care hospital

    Directory of Open Access Journals (Sweden)

    Jagadesh C Reddy

    2015-01-01

    Conclusions: Surgery is a major risk factor for infectious scleritis in our series. Fungus was the most common organism isolated. Thorough debridement and intensive use of medications have improved the outcome.

  2. Bacterial Adhesion & Blocking Bacterial Adhesion

    DEFF Research Database (Denmark)

    Vejborg, Rebecca Munk

    2008-01-01

    tract to the microbial flocs in waste water treatment facilities. Microbial biofilms may however also cause a wide range of industrial and medical problems, and have been implicated in a wide range of persistent infectious diseases, including implantassociated microbial infections. Bacterial adhesion...... is the first committing step in biofilm formation, and has therefore been intensely scrutinized. Much however, still remains elusive. Bacterial adhesion is a highly complex process, which is influenced by a variety of factors. In this thesis, a range of physico-chemical, molecular and environmental parameters......, which influence the transition from a planktonic lifestyle to a sessile lifestyle, have been studied. Protein conditioning film formation was found to influence bacterial adhesion and subsequent biofilm formation considerable, and an aqueous extract of fish muscle tissue was shown to significantly...

  3. Diffusible signal factor (DSF) quorum sensing signal and structurally related molecules enhance the antimicrobial efficacy of antibiotics against some bacterial pathogens

    Science.gov (United States)

    2014-01-01

    Background Extensive use of antibiotics has fostered the emergence of superbugs that are resistant to multidrugs, which becomes a great healthcare and public concern. Previous studies showed that quorum sensing signal DSF (diffusible signal factor) not only modulates bacterial antibiotic resistance through intraspecies signaling, but also affects bacterial antibiotic tolerance through interspecies communication. These findings motivate us to exploit the possibility of using DSF and its structurally related molecules as adjuvants to influence antibiotic susceptibility of bacterial pathogens. Results In this study, we have demonstrated that DSF signal and its structurally related molecules could be used to induce bacterial antibiotic susceptibility. Exogenous addition of DSF signal (cis-11-methyl-2-dodecenoic acid) and its structural analogues could significantly increase the antibiotic susceptibility of Bacillus cereus, possibly through reducing drug-resistant activity, biofilm formation and bacterial fitness. The synergistic effect of DSF and its structurally related molecules with antibiotics on B. cereus is dosage-dependent. Combination of DSF with gentamicin showed an obviously synergistic effect on B. cereus pathogenicity in an in vitro model. We also found that DSF could increase the antibiotic susceptibility of other bacterial species, including Bacillus thuringiensis, Staphylococcus aureus, Mycobacterium smegmatis, Neisseria subflava and Pseudomonas aeruginosa. Conclusion The results indicate a promising potential of using DSF and its structurally related molecules as novel adjuvants to conventional antibiotics for treatment of infectious diseases caused by bacterial pathogens. PMID:24575808

  4. 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.

  5. Control of Postharvest Bacterial Soft Rot by Gamma Irradiation and its Potential Modes of Action

    Directory of Open Access Journals (Sweden)

    Rae-Dong Jeong

    2016-04-01

    Full Text Available Gamma irradiation was evaluated for its in vitro and in vivo antibacterial activity against a postharvest bacterial pathogen, Erwinia carotovora subsp. carotovora (Ecc. Gamma irradiation in a bacteria cell suspension resulted in a dramatic reduction of the viable counts as well as an increase in the amounts of DNA and protein released from the cells. Gamma irradiation showed complete inactivation of Ecc, especially at a dose of 0.6 kGy. In addition, scanning electron microscopy of irradiated cells revealed severe damage on the surface of most bacterial cells. Along with the morphological changes of cells by gamma irradiation, it also affected the membrane integrity in a dose-dependent manner. The mechanisms by which the gamma irradiation decreased the bacterial soft rot can be directly associated with the disruption of the cell membrane of the bacterial pathogen, along with DNA fragmentation, results in dose-dependent cell inactivation. These findings suggest that gamma irradiation has potential as an antibacterial approach to reduce the severity of the soft rot of paprika.

  6. Assessing the impact of various ensilage factors on the fermentation of grass silage using conventional culture and bacterial community analysis techniques.

    Science.gov (United States)

    McEniry, J; O'Kiely, P; Clipson, N J W; Forristal, P D; Doyle, E M

    2010-05-01

    Grass silage is an important ruminant feedstuff on farms during winter. The ensilage of grass involves a natural lactic acid bacterial fermentation under anaerobic conditions, and numerous factors can influence the outcome of preservation. The aim of this study was to investigate the effect of dry matter concentration, ensiling system, compaction and air infiltration on silage bacterial community composition. The impact of these factors was examined using conventional methods of microbial analysis and culture-independent Terminal Restriction Fragment Length Polymorphism (T-RFLP). Silage fermentation was restricted in herbage with a high dry matter concentration, and this was reflected in a shift in the bacterial population present. In contrast, ensiling system had little effect on bacterial community composition. Air infiltration, in the absence of compaction, altered silage bacterial community composition and silage pH. Dry matter concentration and the absence of compaction were the main factors affecting silage microbial community composition, and this was reflected in both the conventional culture-based and T-RFLP data. T-RFLP proved a useful tool to study the factors affecting ensilage. Apart from monitoring the presence or absence of members of the population, shifts in the relative presence of members could be monitored.

  7. PMBLDC motor drive with power factor correction controller

    DEFF Research Database (Denmark)

    George, G.J.; Ramachandran, Rakesh; Arun, N.

    2012-01-01

    This paper presents a boost converter configuration, control scheme and design of single phase power factor controller for permanent magnet brushless DC motor (PMBLDCM) drive. PMBLDC motors are the latest choice of researchers, due to the high efficiency, silent operation, compact size, high...... reliability, and low maintenance requirements. The proposed Power Factor Controller topology improves power quality by improving performance of PMBLDCM drive, such as reduction of AC main current harmonics, near unity power factor. PFC converter forces the drive to draw sinusoidal supply current in phase...... with supply voltage. It uses a boost converter to obtain unity power factor with improved performance. The system includes a speed controller for PMBLDC drive and a voltage controller for boost converter.. The voltage or speed controllers can be realized using proportional integral (PI) controller...

  8. Many means to a common end: the intricacies of (p)ppGpp metabolism and its control of bacterial homeostasis.

    Science.gov (United States)

    Gaca, Anthony O; Colomer-Winter, Cristina; Lemos, José A

    2015-04-01

    In nearly all bacterial species examined so far, amino acid starvation triggers the rapid accumulation of the nucleotide second messenger (p)ppGpp, the effector of the stringent response. While for years the enzymes involved in (p)ppGpp metabolism and the significance of (p)ppGpp accumulation to stress survival were considered well defined, a recent surge of interest in the field has uncovered an unanticipated level of diversity in how bacteria metabolize and utilize (p)ppGpp to rapidly synchronize a variety of biological processes important for growth and stress survival. In addition to the classic activation of the stringent response, it has become evident that (p)ppGpp exerts differential effects on cell physiology in an incremental manner rather than simply acting as a biphasic switch that controls growth or stasis. Of particular interest is the intimate relationship of (p)ppGpp with persister cell formation and virulence, which has spurred the pursuit of (p)ppGpp inhibitors as a means to control recalcitrant infections. Here, we present an overview of the enzymes responsible for (p)ppGpp metabolism, elaborate on the intricacies that link basal production of (p)ppGpp to bacterial homeostasis, and discuss the implications of targeting (p)ppGpp synthesis as a means to disrupt long-term bacterial survival strategies.

  9. Two functional domains conserved in major and alternate bacterial sigma factors.

    Science.gov (United States)

    Stragier, P; Parsot, C; Bouvier, J

    1985-07-22

    Sequences of the sigma factors of Escherichia coli and Bacillus subtilis were aligned with the sequences of two sigma-like proteins, HtpR, involved in the expression of heat-shock genes in E. coli, and SpoIIG, necessary for endospore formation in B. subtilis. An internal region is highly conserved in the four proteins and is proposed to be involved in binding of sigma factors to core RNA polymerase. The carboxy-terminal part of the four proteins presents the characteristic structure found in several prokaryotic DNA-binding proteins and is proposed to be involved in promoter recognition.

  10. Anti-lipopolysaccharide factor in Litopenaeus vannamei (LvALF): a broad spectrum antimicrobial peptide essential for shrimp immunity against bacterial and fungal infection.

    Science.gov (United States)

    de la Vega, Enrique; O'Leary, Nuala A; Shockey, Jessica E; Robalino, Javier; Payne, Caroline; Browdy, Craig L; Warr, Gregory W; Gross, Paul S

    2008-04-01

    Antimicrobial peptides are an essential component of the innate immune system of most organisms. Expressed sequence tag analysis from various shrimp (Litopenaeus vannamei) tissues revealed transcripts corresponding to two distinct sequences (LvALF1 and LvALF2) with strong sequence similarity to anti-lipopolysaccharide factor (ALF), an antimicrobial peptide originally isolated from the horseshoe crab Limulus polyphemus. Full-length clones contained a 528bp transcript with a predicted open reading frame coding for 120 amino acids in LvALF1, and a 623bp transcript with a predicted open reading frame coding for 93 amino acids in LvALF2. A reverse genetic approach was implemented to study the in vivo role of LvALF1 in protecting shrimp from bacterial, fungal and viral infections. Injection of double-stranded RNA (dsRNA) corresponding to the LvALF1 message resulted in a significant reduction of LvALF1 mRNA transcript abundance as determined by qPCR. Following knockdown, shrimp were challenged with low pathogenic doses of Vibrio penaeicida, Fusarium oxysporum or white spot syndrome virus (WSSV) and the resulting mortality curves were compared with controls. A significant increase of mortality in the LvALF1 knockdown shrimp was observed in the V. penaeicida and F. oxysporum infections when compared to controls, showing that this gene has a role in protecting shrimp from both bacterial and fungal infections. In contrast, LvALF1 dsRNA activated the sequence-independent innate anti-viral immune response giving increased protection from WSSV infection.

  11. GATA transcription factor required for immunity to bacterial and fungal pathogens.

    Directory of Open Access Journals (Sweden)

    Samantha Kerry

    Full Text Available In the past decade, Caenorhabditis elegans has been used to dissect several genetic pathways involved in immunity; however, little is known about transcription factors that regulate the expression of immune effectors. C. elegans does not appear to have a functional homolog of the key immune transcription factor NF-kappaB. Here we show that that the intestinal GATA transcription factor ELT-2 is required for both immunity to Salmonella enterica and expression of a C-type lectin gene, clec-67, which is expressed in the intestinal cells and is a good marker of S. enterica infection. We also found that ELT-2 is required for immunity to Pseudomonas aeruginosa, Enterococcus faecalis, and Cryptococcus neoformans. Lack of immune inhibition by DAF-2, which negatively regulates the FOXO transcription factor DAF-16, rescues the hypersusceptibility to pathogens phenotype of elt-2(RNAi animals. Our results indicate that ELT-2 is part of a multi-pathogen defense pathway that regulates innate immunity independently of the DAF-2/DAF-16 signaling pathway.

  12. Predisposing factors for bacterial vaginosis, treatment efficacy and pregnancy outcome among term deliveries; results from a preterm delivery study

    Directory of Open Access Journals (Sweden)

    Jakobsson Tell

    2007-10-01

    Full Text Available Abstract Background Bacterial vaginosis (BV during pregnancy is associated with an increased risk of preterm delivery but little is known about factors that could predict BV. We have analyzed if it is possible to identify a category of pregnant women that should be screened for BV, and if BV would alter the pregnancy outcome at term; we have also studied the treatment efficacy of clindamycin. Methods Prospective BV screening and treatment study of 9025 women in a geographically defined region in southeast Sweden. BV was defined as a modified Nugent score of 6 and above. Data was collected from the Swedish Medical Birth Register. Women allocated to treatment were supplied with vaginal clindamycin cream. The main outcome goals were to identify factors that could predict BV. Results Vaginal smears were consistent with BV criteria in 9.3%. Logistic regression indicates a significant correlation between smoking and BV (p Conclusion BV is more than twice as common among smokers, and there is a higher prevalence in the younger age group. However these two markers for BV do not suffice as a tool for screening, and considering the lack of other risk factors associated with BV, screening of all pregnant women might be a strategy to follow in a program intended to reduce the number of preterm births.

  13. A new poultry semen extender. 4. Effect of antibacterials in control of bacterial contamination in chicken semen.

    Science.gov (United States)

    Sexton, T J; Jacobs, L A; McDaniel, G R

    1980-02-01

    Forty antibacterials were qualitatively and quantitatively tested for controlling aerobic bacterial contamination without affecting viability of semen. Semen samples were collected aseptically, diluted 1:4 with the Beltsville poultry semen extender containing one of 40 antibiotics and held for 0, 24, 48, and 72 hr at 5 C. Semen samples were monitored at each storage interval for bacterial counts, sperm motility, sperm counts, and fertilizing capacity. Gentamicin (2.5 microgram/ml), kanamycin (31.2 microgram/ml), neomycin (62.5 microgram/ml), and tobramycin (2.5 microgram/ml) were the only antibacterials tested which controlled microbial growth without affecting sperm viability for up to 24 hr storage at 5 C. Tobramycin maintained fertility equal to that of the non-antibiotic control up to 24 hr storage. Neomycin maintained higher levels of fertility in semen stored for 48 and 72 hr than in semen of controls to all other treatments for the same storage periods and to undiluted, unstored semen. The conclusion from these studies is that the control of aerobic microbial growth in chicken semen has little influence on the maintenance of sperm viability during low temperature storage.

  14. Temperature Dependence of Factors Controlling Isoprene Emissions

    Science.gov (United States)

    Duncan, Bryan N.; Yoshida, Yasuko; Damon, Megan R.; Douglass, Anne R.; Witte, Jacquelyn C.

    2009-01-01

    We investigated the relationship of variability in the formaldehyde (HCHO) columns measured by the Aura Ozone Monitoring Instrument (OMI) to isoprene emissions in the southeastern United States for 2005-2007. The data show that the inferred, regional-average isoprene emissions varied by about 22% during summer and are well correlated with temperature, which is known to influence emissions. Part of the correlation with temperature is likely associated with other causal factors that are temperature-dependent. We show that the variations in HCHO are convolved with the temperature dependence of surface ozone, which influences isoprene emissions, and the dependence of the HCHO column to mixed layer height as OMI's sensitivity to HCHO increases with altitude. Furthermore, we show that while there is an association of drought with the variation in HCHO, drought in the southeastern U.S. is convolved with temperature.

  15. Influences of environmental factors on bacterial extracellular polymeric substances production in porous media

    Science.gov (United States)

    Xia, Lu; Zheng, Xilai; Shao, Haibing; Xin, Jia; Peng, Tao

    2014-11-01

    Bioclogging of natural porous media occurs frequently under a wide range of conditions. It may influence the performance of permeable reactive barrier and constructed wetland. It is also one of the factors that determine the effect of artificial groundwater recharge and in situ bioremediation process. In this study, a series of percolation column experiments were conducted to simulate bioclogging process in porous media. The predominant bacteria in porous media which induced clogging were identified to be Methylobacterium, Janthinobacterium, Yersinia, Staphylococcus and Acidovorax, most of which had been shown to effectively produce viscous extracellular polymeric substances (EPS). The column in which EPS production was maximized also coincided with the largest reduction in saturated hydraulic conductivity of porous media. In addition, carbon concentration was the most significant factor to affect polysaccharide, protein and EPS secretion, followed by phosphorus concentration and temperature. The coupled effect of carbon and phosphorus concentration was also very important to stimulate polysaccharide and EPS production.

  16. Role of bacterial and genetic factors in gastric cancer in Costa Rica

    Institute of Scientific and Technical Information of China (English)

    Sergio A Con; Hiroaki Takeuchi; Gil R Con-Chin; Vicky G Con-Chin; Nobufumi Yasuda; Reinaldo Con-Wong

    2009-01-01

    AIM: To evaluate several risk factors for gastric cancer (GC) in Costa Rican regions with contrasting GC incidence rate (GCIR). METHODS: According to GCIR, 191 Helicobacter pylori ( H pylori)-positive patients were classified into groups A (high GCIR, n = 101) and B (low GCIR, n = 90). Human DNA obtained from biopsy specimens was used in the determination of polymorphisms of the genes coding for interleukin (IL)-1o play a major role in GCIR variability in Costa Rica.

  17. Food safety in raw milk production: risk factors associated to bacterial DNA contamination.

    Science.gov (United States)

    Cerva, Cristine; Bremm, Carolina; Reis, Emily Marques dos; Bezerra, André Vinícius Andrade; Loiko, Márcia Regina; Cruz, Cláudio Estêvão Farias da; Cenci, Alexander; Mayer, Fabiana Quoos

    2014-06-01

    While human illness from milkborne pathogens may be linked to contamination of the product after pasteurization or improper pasteurization, such diseases are usually associated with consumption of raw milk or its by-products. Molecular biology tools were applied to investigate contamination by Listeria monocytogenes, Salmonella spp., some pathogenic strains of Escherichia coli, and Campylobacter jejuni in 548 raw milk samples from 125 dairy farms established in two regions from southern Brazil. Moreover, 15 variables were evaluated for their association with raw milk contamination levels, and the risk factors were determined by multiple regression analysis. Salmonella spp. were more frequently detected, followed by pathogenic E. coli. There was difference in contamination index between the regions, in which risk factors such as temporary cattle confinement, low milk production, low milking machine cleaning frequency, and milk storage area without tile walls were identified. The risk factors were specific to each region studied. Nevertheless, the data can be used to improve milk quality of dairy farms/herds with similar management practices.

  18. Polyketide chain length control by chain length factor.

    Science.gov (United States)

    Tang, Yi; Tsai, Shiou-Chuan; Khosla, Chaitan

    2003-10-22

    Bacterial aromatic polyketides are pharmacologically important natural products. A critical parameter that dictates product structure is the carbon chain length of the polyketide backbone. Systematic manipulation of polyketide chain length represents a major unmet challenge in natural product biosynthesis. Polyketide chain elongation is catalyzed by a heterodimeric ketosynthase. In contrast to homodimeric ketosynthases found in fatty acid synthases, the active site cysteine is absent from the one subunit of this heterodimer. The precise role of this catalytically silent subunit has been debated over the past decade. We demonstrate here that this subunit is the primary determinant of polyketide chain length, thereby validating its designation as chain length factor. Using structure-based mutagenesis, we identified key residues in the chain length factor that could be manipulated to convert an octaketide synthase into a decaketide synthase and vice versa. These results should lead to novel strategies for the engineered biosynthesis of hitherto unidentified polyketide scaffolds.

  19. Risk factors for caries - control and prevention

    Directory of Open Access Journals (Sweden)

    Melida Hasanagić

    2008-08-01

    Full Text Available Objectives. To investigate a prevalence of caries, filled permanentand extracted permanent teeth, as well as caries risk factors inschool children aged 7, 9 and 11.Methods. The survey included 800 children (296 children aged7; 254 children aged 9 and 250 children aged 11 from the MostarMunicipality, 400 of them living in both rural and urban areas.A dental mirror and standard light of dental chair were used forexamination. The DMF index (Dental Caries, Missing Teeth andFilled Teeth was determined, as well as failure in keeping teethhygiene, sugar intake with food, and incidence of oral cavity infection.Results. The dental state of permanent teeth in children aged 7and 9 has shown significant difference between the children fromrural and urban areas (p < 0,001. Out of 2,698 and 2,790 permanentteeth in children aged 11 from rural and urban areas, 1,086(40,25 % and 884 (31.68 % had caries, respectively (p < 0.01.The difference between these groups of children has been foundin relation to the index of oral hygiene too (p < 0.05.Conclusion. An identification of risk groups for getting caries wasvery important and could help health and social structures to maintaintheir programs in order to improve oral health.

  20. Cancro bacteriano da videira: etiologia, epidemiologia e medidas de controle Bacterial canker of grapevine: etiology, epidemiology and control strategies

    Directory of Open Access Journals (Sweden)

    Ana Rosa Peixoto Nascimento

    2004-02-01

    Full Text Available No início de 1998, o cancro bacteriano da videira, causado pela bactéria Xanthomonas campestris pv. viticola, foi detectado pela primeira vez, no Brasil, em parreirais do Submédio São Francisco, onde a doença vem ocasionando prejuízos nas cultivares suscetíveis Red Globe, Itália, Festival, Brasil, Piratininga, Patrícia, Benitaka e Catalunha. Os sintomas, nas folhas, surgem como pontos necróticos (1 a 2mm de diâmetro com ou sem halos amarelados, algumas vezes coalescendo e causando a morte de extensas áreas do limbo foliar. Nas nervuras e pecíolos, nos ramos e ráquis dos frutos, formam-se manchas escuras alongadas que evoluem para fissuras longitudinais de coloração negra conhecidas como cancros. Descoloração vascular é também observada. As bagas são desuniformes em tamanho e cor podendo apresentar lesões necróticas. A disseminação do patógeno ocorre através de material propagativo infectado, material de colheita (contentores, tesouras de poda e raleio, luvas, tratos culturais (desbrota, poda, raleio de bagas, colheita, ventos e chuvas. Apesar da região apresentar um curto período chuvoso, a disseminação da bactéria é mais eficiente durante essa época. Em condições de umidade e temperatura elevadas, o patógeno sobrevive em restos de cultura. Para o controle da doença, recomenda-se o uso de material propagativo sadio, inspeção no campo, poda drástica de órgãos infectados, eliminação de plantas severamente infectadas, condução da época de poda de produção, desinfestação de veículos, de equipamentos e de materiais para poda, utilização de fungicidas protetores cúpricos e tiocarbamatos, e utilização de quebra-ventos para reduzir a disseminação do patógeno.In the begining of 1998, bacterial canker of grapevine, caused by the bacterium Xanthomonas campestris pv. viticola, was detected for the first time in Brazil in vineyards of the “Submédio São Francisco”. Losses in susceptible

  1. Green and brown propolis: efficient natural biocides for the control of bacterial contamination of alcoholic fermentation of distilled beverage

    Directory of Open Access Journals (Sweden)

    Márcia Justino Rossini Mutton

    2014-12-01

    Full Text Available This study aimed to evaluate the efficiency of natural biocides, brown and green propolis, for the control of bacterial contamination in the production of sugarcane spirit. The treatments consisted of brown and green propolis extracts, ampicillin, and a control and were assessed at the beginning and end of harvest season in ten fermentation cycles. In the microbiological analyses, the lactic acid bacteria were quantified in the inoculum before and after the treatment with biocides, and the viability of yeast cells during fermentation was evaluated. The levels of acids, glycerol, total residual reducing sugars, and ethanol were analyzed for the wine resulting from each fermentation cycle. A reduction in the number of bacterial contaminants in the inoculum in the treatments with the natural biocides was observed, but it did not affect the viability of yeast cells. The control of the contaminants led to the production of higher levels of ethanol and reduced acidity in the wine produced. The results of the use of brown and green propolis to control the growth microorganisms in the fermentation of sugarcane spirit can be of great importance for using alternative strategies to synthetic antibacterials in fermentation processes including other distilled beverage or spirits.

  2. Fibronectin in the ascitic fluid of cirrhotic patients: correlation with biochemical risk factors for the development of spontaneous bacterial peritonitis

    Directory of Open Access Journals (Sweden)

    R.C.A. Mesquita

    1997-07-01

    Full Text Available Cirrhotic patients (23 with alcoholic cirrhosis, 5 with posthepatitic cirrhosis and 2 with cryptogenic cirrhosis with ascites and portal hypertension were studied and divided into two groups corresponding to high or low risk to develop spontaneous bacterial peritonitis (SBP related to the concentration of total protein in the ascitic fluid (A-TP: group I (high risk: A-TP£1.5 g/dl and group II (low risk: A-TP>1.5 g/dl. Fibronectin (FN, C3 and C4 concentrations were measured by radial immunodiffusion while total protein was measured by the biuret method. The mean values (group I vs group II of C3 (12.59 ± 4.72 vs 24.53 ± 15.58 mg/dl, C4 (4.26 ± 3.87 vs 7.26 ± 4.14 mg/dl and FN (50.47 ± 12.49 vs 75.89 ± 24.70 mg/dl in the ascitic fluid were significantly lower (P<0.05 in the group considered to be at high risk for SBP. No significant difference was observed in the plasma/ascites fibronectin ratio (3.91 ± 1.21 vs 3.80 ± 1.26 or gradient (131.46 ± 64.01 vs 196.96 ± 57.38 between groups. Fibronectin in ascites was significantly correlated to C3 (r = 0.76, C4 (r = 0.58, total protein (r = 0.73 and plasma FN (r = 0.58 (P<0.05. The data suggest that the FN concentration in ascites is related to the opsonic capacity of this fluid, and that its concentration in the ascitic fluid may be a biochemical risk factor indicator for the development of spontaneous bacterial peritonitis

  3. Accommodating the bacterial decoding release factor as an alien protein among the RNAs at the active site of the ribosome

    Institute of Scientific and Technical Information of China (English)

    Elizabeth S Poole; David J Young; Marjan E Askarian-Amiri; Debbie-Jane G Scarlett; Warren P Tate

    2007-01-01

    The decoding release factor (RF) triggers termination of protein synthesis by functionally mimicking a tRNA to span the decoding centre and the peptidyl transferase centre (PTC) of the ribosome. Structurally, it must fit into a site crafted for a tRNA and surrounded by five other RNAs, namely the adjacent peptidyl tRNA carrying the completed polypeptide, the mRNA and the three rRNAs. This is achieved by extending a structural domain from the body of the protein that results in a critical conformational change allowing it to contact the PTC. A structural model of the bacterial termination complex with the accommodated RF shows that it makes close contact with the first, second and third bases of the stop codon in the mRNA with two separate loops of structure: the anticodon loop and the loop at the tip of helix a5. The anticodon loop also makes contact with the base following the stop codon that is known to strongly influence termination efficiency. It confirms the close contact of domain 3 of the protein with the key RNA structures of the PTC. The mRNA signal for termination includes sequences upstream as well as downstream of the stop codon, and this may reflect structural restrictions for specific combinations of tRNA and RF to be bound onto the ribosome together. An unbiased SELEX approach has been investigated as a tool to identify potential rRNA-binding contacts of the bacterial RF in its different binding conformations within the active centre of the ribosome.

  4. Bacterial elongation factors EF-Tu, their mutants, chimeric forms, and domains: isolation and purification.

    Science.gov (United States)

    Jonák, J

    2007-04-15

    Prokaryotic elongation factors EF-Tu form a family of homologous, three-domain molecular switches catalyzing the binding of aminoacyl-tRNAs to ribosomes during the process of mRNA translation. They are GTP-binding proteins, or GTPases. Binding of GTP or GDP regulates their conformation and thus their activity. Because of their particular structure and regulation, various activities (also outside of the translation system) and a relative abundance they represent attractive tools for studies of many basic but still not fully understood mechanisms both of the translation process, the structure-function relationships in EF-Tu molecules themselves and proteins and energy transduction mechanisms in general. The review critically summarizes procedures for the isolation and purification of native and engineered eubacterial elongation factors EF-Tu and their mutants on a large as well as small scale. Current protocols for the purification of both native and polyHis-tagged or glutathione-S-transferase (GST)-tagged EF-Tu proteins and their variants using conventional procedures and the Ni-NTA-Agarose or Glutathione Sepharose are presented.

  5. Bacterial diversity in oral samples of children in niger with acute noma, acute necrotizing gingivitis, and healthy controls.

    Directory of Open Access Journals (Sweden)

    Ignacio Bolivar

    Full Text Available BACKGROUND: Noma is a gangrenous disease that leads to severe disfigurement of the face with high morbidity and mortality, but its etiology remains unknown. Young children in developing countries are almost exclusively affected. The purpose of the study was to record and compare bacterial diversity in oral samples from children with or without acute noma or acute necrotizing gingivitis from a defined geographical region in Niger by culture-independent molecular methods. METHODS AND PRINCIPAL FINDINGS: Gingival samples from 23 healthy children, nine children with acute necrotizing gingivitis, and 23 children with acute noma (both healthy and diseased oral sites were amplified using "universal" PCR primers for the 16 S rRNA gene and pooled according to category (noma, healthy, or acute necrotizing gingivitis, gender, and site status (diseased or control site. Seven libraries were generated. A total of 1237 partial 16 S rRNA sequences representing 339 bacterial species or phylotypes at a 98-99% identity level were obtained. Analysis of bacterial composition and frequency showed that diseased (noma or acute necrotizing gingivitis and healthy site bacterial communities are composed of similar bacteria, but differ in the prevalence of a limited group of phylotypes. Large increases in counts of Prevotella intermedia and members of the Peptostreptococcus genus are associated with disease. In contrast, no clear-cut differences were found between noma and non-noma libraries. CONCLUSIONS: Similarities between acute necrotizing gingivitis and noma samples support the hypothesis that the disease could evolve from acute necrotizing gingivitis in certain children for reasons still to be elucidated. This study revealed oral microbiological patterns associated with noma and acute necrotizing gingivitis, but no evidence was found for a specific infection-triggering agent.

  6. Prevalence and Risk Factors for Bacterial Vaginosis and Other Vulvovaginitis in a Population of Sexually Active Adolescents from Salvador, Bahia, Brazil

    Directory of Open Access Journals (Sweden)

    Rita Elizabeth Moreira Mascarenhas

    2012-01-01

    Full Text Available Bacterial vaginosis, trichomoniasis, and genital candidiasis are considered the main etiologies of vulvovaginitis. Few studies estimate the prevalence of vulvovaginitis among adolescents, especially in Brazil. This study aimed to determine the prevalence and main risk factors associated with bacterial vaginosis and genital infection by C. albicans and Trichomonas vaginalis among a group of adolescents from Salvador, Bahia, Brazil. One hundred sexually active adolescents followed at an adolescent gynecology clinic were included. Endocervical and vaginal samples were obtained during gynecological examination. Nugent criteria were applied for the diagnosis of bacterial vaginosis. For Candida albicans and Trichomonas vaginalis detection, culture in Sabouraud agar plates and Papanicolaou cytology were used, respectively. The mean age of participants was 16.6±1.6 years. The prevalence of bacterial vaginosis was 20% (95% CI 12–28 and of genital infection by Candida was 22% (95% CI 14–30. Vaginal cytology detected Trichomonas vaginalis in one patient. Alcohol, tobacco, and illegal drug use (P=0.02 and multiple lifetime partners were statistically related to bacterial vaginosis (P=0.01. The prevalence of bacterial vaginosis and genital candidiasis was similar to other studies carried out among adolescents worldwide.

  7. Prevalence and risk factors for bacterial vaginosis and other vulvovaginitis in a population of sexually active adolescents from Salvador, Bahia, Brazil.

    Science.gov (United States)

    Mascarenhas, Rita Elizabeth Moreira; Machado, Márcia Sacramento Cunha; Costa e Silva, Bruno Fernando Borges da; Pimentel, Rodrigo Fernandes Weyll; Ferreira, Tatiana Teixeira; Leoni, Fernanda Maria Silva; Grassi, Maria Fernanda Rios

    2012-01-01

    Bacterial vaginosis, trichomoniasis, and genital candidiasis are considered the main etiologies of vulvovaginitis. Few studies estimate the prevalence of vulvovaginitis among adolescents, especially in Brazil. This study aimed to determine the prevalence and main risk factors associated with bacterial vaginosis and genital infection by C. albicans and Trichomonas vaginalis among a group of adolescents from Salvador, Bahia, Brazil. One hundred sexually active adolescents followed at an adolescent gynecology clinic were included. Endocervical and vaginal samples were obtained during gynecological examination. Nugent criteria were applied for the diagnosis of bacterial vaginosis. For Candida albicans and Trichomonas vaginalis detection, culture in Sabouraud agar plates and Papanicolaou cytology were used, respectively. The mean age of participants was 16.6 ± 1.6 years. The prevalence of bacterial vaginosis was 20% (95% CI 12-28) and of genital infection by Candida was 22% (95% CI 14-30). Vaginal cytology detected Trichomonas vaginalis in one patient. Alcohol, tobacco, and illegal drug use (P = 0.02) and multiple lifetime partners were statistically related to bacterial vaginosis (P = 0.01). The prevalence of bacterial vaginosis and genital candidiasis was similar to other studies carried out among adolescents worldwide.

  8. Fusidic acid targets elongation factor G in several stages of translocation on the bacterial ribosome.

    Science.gov (United States)

    Borg, Anneli; Holm, Mikael; Shiroyama, Ikue; Hauryliuk, Vasili; Pavlov, Michael; Sanyal, Suparna; Ehrenberg, Måns

    2015-02-06

    The antibiotic fusidic acid (FA) targets elongation factor G (EF-G) and inhibits ribosomal peptide elongation and ribosome recycling, but deeper mechanistic aspects of FA action have remained unknown. Using quench flow and stopped flow experiments in a biochemical system for protein synthesis and taking advantage of separate time scales for inhibited (10 s) and uninhibited (100 ms) elongation cycles, a detailed kinetic model of FA action was obtained. FA targets EF-G at an early stage in the translocation process (I), which proceeds unhindered by the presence of the drug to a later stage (II), where the ribosome stalls. Stalling may also occur at a third stage of translocation (III), just before release of EF-G from the post-translocation ribosome. We show that FA is a strong elongation inhibitor (K50% ≈ 1 μm), discuss the identity of the FA targeted states, and place existing cryo-EM and crystal structures in their functional context.

  9. Caries-related factors and bacterial composition of supragingival plaques in caries free and caries active Algerian adults

    Institute of Scientific and Technical Information of China (English)

    Amina Hoceini; Nihel Klouche Khelil; Ilhem Ben-Yelles; Amine Mesli; Sara Ziouani; Lotfi Ghellai; Nadia Aissaoui; Fatima Nas; Mounia Arab

    2016-01-01

    Objective: To compare oral hygiene practices, education and social background, food intake and oral malodor of Algerian adults suffering from dental caries with normal controls, and to determine and compare the bacterial composition of the supragingival plaques from the above-mentioned groups.Methods: Participants completed a questionnaire and were clinically examined for dental caries using decayed, missing and filled teeth index according to the criteria laid down by the World Health Organization. Supragingival plaque samples were collected from 50 caries-free adults(CF) and 50 caries-active adults(CA). Standard procedures of culture and identification of aerobic and anaerobic bacteria were used. Data were analyzed using Chi-square test.Results: A total of 117 bacterial strains were isolated from supragingival plaques in CF group subjects, 76(64.96%) of them belonged to 9 aerobic genera, and 41(35.04%) to 9anaerobic genera(P < 0.05). While in the second group, 199 strains were isolated, 119(59.80%) of the strains belonged to 10 aerobic genera and 80(40.20%) to 10 anaerobic bacteria(P < 0.05). Streptococcus mutans, Enterococcus faecium, Aerococcus viridans,Actinomyces meyeri, Lactobacillus acidophilus and Eubacterium limosum showed a significantly higher prevalence in the CA group(P < 0.05). The findings revealed that CA group had a high sugar intake(80%). A significantly higher frequency of tooth brushing(P < 0.000) and a significantly less self-reported oral malodor(P < 0.000) and tooth pain(P < 0.000) were found in CF group, while there was no association of socioeconomic levels and intake of meal snacks with dental caries.Conclusions: This study confirms the association of some aciduric bacteria with caries formation, and a direct association of sugar intake and cultural level with dental caries.Furthermore, oral hygiene practices minimize the prevalence of tooth decay.

  10. Role of environmental factors for the vertical distribution (0–1000 m of marine bacterial communities in the NW Mediterranean Sea

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    M. Goutx

    2008-05-01

    Full Text Available Bacterioplankton play a central role in energy and matter fluxes at the sea, yet the factors that constrain their variation in the marine systems are still poorly understood. Here we show the explanatory power of multivariate statistical analysis of bacterial community structures coupled with fine measurements of numerous environmental parameters. We gathered and analysed data from a one month sampling period from the surface to 1000 m depth at the JGOFS-DYFAMED station (NW Mediterranean Sea. This station is characterized by very poor horizontal advection currents what makes it an ideal model to test hypothesis on the causes of vertical stratification of bacterial communities. Capillary electrophoresis single strand conformation polymorphism (CE-SSCP fingerprinting profiles analyzed using multivariate statistical methods demonstrated a vertical zonation of bacterial assemblages in three layers, above, in or just below the chlorophyll maximum and deeper, that remained stable during the entire sampling period. Through the use of direct gradient multivariate ordination analyses we demonstrate that a complex array of biogeochemical parameters is the driving force behinds bacterial community structure shifts in the water column. Physico-chemical parameters such as phosphate, nitrate, salinity and to a lesser extend temperature, oxygen, dissolve organic carbon and photosynthetically active radiation acted in synergy to explain bacterial assemblages changes with depth. Analysis of lipid biomarkers of the organic matter sources and fates suggested that bacterial community structure at the surface layers was in part explained by lipids from chloroplast origin. Further detailed analysis of pigment-based phytoplankton diversity gave evidence of a compartmentalized influence of several phytoplankton groups on bacterial community structure in the first 150 m depth. This study is probably the first example of an analysis employing a complex environmental

  11. Sample Dilution and Bacterial Community Composition Influence Empirical Leucine-to-Carbon Conversion Factors in Surface Waters of the World's Oceans

    KAUST Repository

    Teira, Eva

    2015-09-25

    The transformation of leucine incorporation rates to prokaryotic carbon production rates requires the use of either theoretical or empirically determined conversion factors. Empirical leucine-to-carbon conversion factors (eCFs) vary widely across environments, and little is known about their potential controlling factors. We conducted 10 surface seawater manipulation experiments across the world\\'s oceans, where the growth of the natural prokaryotic assemblages was promoted by filtration (i.e., removal of grazers [F treatment]) or filtration combined with dilution (i.e., also relieving resource competition [FD treatment]). The impact of sunlight exposure was also evaluated in the FD treatments, and we did not find a significant effect on the eCFs. The eCFs varied from 0.09 to 1.47 kg C mol Leu−1 and were significantly lower in the FD than in the F samples. Also, changes in bacterial community composition during the incubations, as assessed by automated ribosomal intergenic spacer analysis (ARISA), were more pronounced in the FD than in the F treatments, compared to unmanipulated controls. Thus, we discourage the common procedure of diluting samples (in addition to filtration) for eCF determination. The eCFs in the filtered treatment were negatively correlated with the initial chlorophyll a concentration, picocyanobacterial abundance (mostly Prochlorococcus), and the percentage of heterotrophic prokaryotes with high nucleic acid content (%HNA). The latter two variables explained 80% of the eCF variability in the F treatment, supporting the view that both Prochlorococcus and HNA prokaryotes incorporate leucine in substantial amounts, although this results in relatively low carbon production rates in the oligotrophic ocean.

  12. Chalcopyrite leaching: The rate controlling factors

    Science.gov (United States)

    Li, J.; Kawashima, N.; Kaplun, K.; Absolon, V. J.; Gerson, A. R.

    2010-05-01

    The processes that determine the rate of chalcopyrite leaching are central to understanding how chalcopyrite (CuFeS 2) behaves under the environmentally adverse conditions of acid rock drainage. To this end the effect of the acid anion on chalcopyrite leach rates using a variety of acidic media (H 2SO 4, HClO 4, HCl and H 2SO 4 with 0.25 M NaCl) under carefully controlled solution conditions (pH 1 and 2, Eh 750 mV (SHE) and 75 °C) has been examined. These conditions have been chosen to enable sufficient leach rates for accurate experimental determination and to compare to the previous mechanistic analysis carried out by Harmer et al. (2006). Extensive surface analysis of leach residues demonstrated that variations in the surface speciation could not be responsible for the observed variations in leach rate. The rate of Cu release, however, was found to be first order with respect to Fe 3+ activity and inversely proportional with respect to H + activity to the power of 0.7: {1}/{S}{dC}/{dt}=(2.0±0.2){a}/{aH0.7} where S is the relative surface area, C is concentration of Cu in the solution (M), t is the time (h), 2.0 is the rate constant (M 0.7 h -1) and a and a are Fe 3+ and H + activities, respectively (M). The rate model was further validated against additional leaches carried out in H 2SO 4 media with the initial addition of Fe 3+ (8 mM as Fe 2(SO 4) 3) at 75 °C under various pH and Eh regimes. The only condition under which this rate model was found not to hold was at simultaneously low a and high a, that is at pH 1 and a<5×10-5M, where the concentration of dissolved O 2 may be leach rate determining.

  13. Effects of allicin on the formation of Pseudomonas aeruginosa biofinm and the production of quorum-sensing controlled virulence factors.

    Science.gov (United States)

    Lihua, Lin; Jianhuit, Wang; Jialini, Yu; Yayin, Li; Guanxin, Liu

    2013-01-01

    The Gram-negative Pseudomonas aeruginosa bacterial pathogen is reputed for its resistance to multiple antibiotics, and this property is strongly associated with the development of biofilms. Bacterial biofilms form by aggregation of microorganisms on a solid surface and secretion of an extracellular polysaccharide substances that acts as a physical protection barrier for the encased bacteria. In addition, the P aeruginosa quorum-sensing system contributes to antibiotic resistance by regulating the expression of several virulence factors, including exotoxin A, elastase, pyoverdin and rhamnolipid. The organosulfur compound allicin, derived from garlic, has been shown to inhibit both surface-adherence of bacteria and production of virulence factors. In this study, the effects of allicin on P aeruginosa biofilm formation and the production of quorum-sensing controlled virulence factors were investigated. The results demonstrated that allicin could inhibit early bacterial adhesion, reduce EPS secretion, and down-regulate virulence factors' production. Collectively, these findings suggest the potential of allicin as a therapeutic agent for controlling P aeruginosa biofilm.

  14. Bacterial diseases affecting apple

    Science.gov (United States)

    Bacterial diseases of plants are usually difficult to control and often require a combination of control measures to successfully manage the disease. There are often stark differences between the means available to control bacterial diseases in annual crops versus a woody tree crop, such as apple. ...

  15. Functional role of pyruvate kinase from Lactobacillus bulgaricus in acid tolerance and identification of its transcription factor by bacterial one-hybrid.

    Science.gov (United States)

    Zhai, Zhengyuan; An, Haoran; Wang, Guohong; Luo, Yunbo; Hao, Yanling

    2015-11-19

    Lactobacillus delbrueckii subsp. bulgaricus develops acid tolerance response when subjected to acid stress conditions, such as the induction of enzymes associated with carbohydrate metabolism. In this study, pyk gene encoding pyruvate kinase was over-expressed in heterologous host Lactococcus lactis NZ9000, and SDS-PAGE analysis revealed the successful expression of this gene in NZ9000. The survival rate of Pyk-overproducing strain was 45-fold higher than the control under acid stress condition (pH 4.0). In order to determine the transcription factor (TF) which regulates the expression of pyk by bacterial one-hybrid, we constructed a TF library including 65 TFs of L. bulgaricus. Western blotting indicated that TFs in this library could be successfully expressed in host strains. Subsequently, the promoter of pfk-pyk operon in L. bulgaricus was identified by 5'-RACE PCR. The bait plasmid pH3U3-p01 carrying the deletion fragment of pfk-pyk promoter captured catabolite control protein A (CcpA) which could regulate the expression of pyk by binding to a putative catabolite-responsive element (5'-TGTAAGCCCTAACA-3') upstream the -35 region. Real-time qPCR analysis revealed the transcription of pyk was positively regulated by CcpA. This is the first report about identifying the TF of pyk in L. bulgaricus, which will provide new insight into the regulatory network.

  16. Deletion of Mycobacterium tuberculosis sigma factor E results in delayed time to death with bacterial persistence in the lungs of aerosol-infected mice.

    Science.gov (United States)

    Ando, Masaru; Yoshimatsu, Tetsuyuki; Ko, Chiew; Converse, Paul J; Bishai, William R

    2003-12-01

    The stress-induced extracytoplasmic sigma factor E (SigE) of Mycobacterium tuberculosis shows increased expression after heat shock, sodium dodecyl sulfate treatment, and oxidative stress, as well as after phagocytosis in macrophages. We report that deletion of sigE results in delayed lethality in mice without a significant reduction of bacterial numbers in lungs.

  17. Risk factors for otitis media in children with special emphasis on the role of colonization with bacterial airway pathogens: The Generation R study

    NARCIS (Netherlands)

    J.A.M. Labout (Joost); L. Duijts (Liesbeth); A. Lebon (Ankie); R. de Groot (Ronald); A. Hofman (Albert); V.W.V. Jaddoe (Vincent); H.A. Verbrugh (Henri); P.W.M. Hermans (Peter); H.A. Moll (Henriëtte)

    2011-01-01

    textabstractAcute otitis media is the most frequent diagnosis in children visiting physicians' offices. Risk factors for otitis media have been widely studied. Yet, the correlation between bacterial carriage and the development of otitis media is not entirely clear. Our aim was to study in a

  18. Risk factors for otitis media in children with special emphasis on the role of colonization with bacterial airway pathogens: the Generation R study

    NARCIS (Netherlands)

    Labout, J.A.; Duijts, L.; Lebon, A.; Groot, R. de; Hofman, A.; Jaddoe, V.V.; Verbrugh, H.A.; Hermans, P.W.M.; Moll, H.A.

    2011-01-01

    Acute otitis media is the most frequent diagnosis in children visiting physicians' offices. Risk factors for otitis media have been widely studied. Yet, the correlation between bacterial carriage and the development of otitis media is not entirely clear. Our aim was to study in a population-based

  19. Structure of a bacterial quorum-sensing transcription factor complexed with pheromone and DNA.

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, R.; Pappas, T.; Brace, J.; Miller, P.; Oulmassov, T.; Molyneaux, J.; Anderson, J.; Bashkin, J.; Winans, S.; Joachimiak, A.; Biosciences Division; Cornell Univ.; Monsanto Co.

    2002-06-27

    Many proteobacteria are able to monitor their population densities through the release of pheromones known as N-acylhomoserine lactones. At high population densities, these pheromones elicit diverse responses that include bioluminescence, biofilm formation, production of antimicrobials, DNA exchange, pathogenesis and symbiosis1. Many of these regulatory systems require a pheromone-dependent transcription factor similar to the LuxR protein of Vibrio fischeri. Here we present the structure of a LuxR-type protein. TraR of Agrobacterium tumefaciens was solved at 1.66 A as a complex with the pheromone N-3-oxooctanoyl-l-homoserine lactone (OOHL) and its TraR DNA-binding site. The amino-terminal domain of TraR is an {alpha}/{beta}/{alpha} sandwich that binds OOHL, whereas the carboxy-terminal domain contains a helix-turn-helix DNA-binding motif. The TraR dimer displays a two-fold symmetry axis in each domain; however, these two axes of symmetry are at an approximately 90 degree angle, resulting in a pronounced overall asymmetry of the complex. The pheromone lies fully embedded within the protein with virtually no solvent contact, and makes numerous hydrophobic contacts with the protein as well as four hydrogen bonds: three direct and one water-mediated.

  20. Fusidic Acid Targets Elongation Factor G in Several Stages of Translocation on the Bacterial Ribosome*

    Science.gov (United States)

    Borg, Anneli; Holm, Mikael; Shiroyama, Ikue; Hauryliuk, Vasili; Pavlov, Michael; Sanyal, Suparna; Ehrenberg, Måns

    2015-01-01

    The antibiotic fusidic acid (FA) targets elongation factor G (EF-G) and inhibits ribosomal peptide elongation and ribosome recycling, but deeper mechanistic aspects of FA action have remained unknown. Using quench flow and stopped flow experiments in a biochemical system for protein synthesis and taking advantage of separate time scales for inhibited (10 s) and uninhibited (100 ms) elongation cycles, a detailed kinetic model of FA action was obtained. FA targets EF-G at an early stage in the translocation process (I), which proceeds unhindered by the presence of the drug to a later stage (II), where the ribosome stalls. Stalling may also occur at a third stage of translocation (III), just before release of EF-G from the post-translocation ribosome. We show that FA is a strong elongation inhibitor (K50% ≈ 1 μm), discuss the identity of the FA targeted states, and place existing cryo-EM and crystal structures in their functional context. PMID:25451927

  1. A Salmonella small non-coding RNA facilitates bacterial invasion and intracellular replication by modulating the expression of virulence factors.

    Directory of Open Access Journals (Sweden)

    Hao Gong

    2011-09-01

    Full Text Available Small non-coding RNAs (sRNAs that act as regulators of gene expression have been identified in all kingdoms of life, including microRNA (miRNA and small interfering RNA (siRNA in eukaryotic cells. Numerous sRNAs identified in Salmonella are encoded by genes located at Salmonella pathogenicity islands (SPIs that are commonly found in pathogenic strains. Whether these sRNAs are important for Salmonella pathogenesis and virulence in animals has not been reported. In this study, we provide the first direct evidence that a pathogenicity island-encoded sRNA, IsrM, is important for Salmonella invasion of epithelial cells, intracellular replication inside macrophages, and virulence and colonization in mice. IsrM RNA is expressed in vitro under conditions resembling those during infection in the gastrointestinal tract. Furthermore, IsrM is found to be differentially expressed in vivo, with higher expression in the ileum than in the spleen. IsrM targets the mRNAs coding for SopA, a SPI-1 effector, and HilE, a global regulator of the expression of SPI-1 proteins, which are major virulence factors essential for bacterial invasion. Mutations in IsrM result in disregulation of expression of HilE and SopA, as well as other SPI-1 genes whose expression is regulated by HilE. Salmonella with deletion of isrM is defective in bacteria invasion of epithelial cells and intracellular replication/survival in macrophages. Moreover, Salmonella with mutations in isrM is attenuated in killing animals and defective in growth in the ileum and spleen in mice. Our study has shown that IsrM sRNA functions as a pathogenicity island-encoded sRNA directly involved in Salmonella pathogenesis in animals. Our results also suggest that sRNAs may represent a distinct class of virulence factors that are important for bacterial infection in vivo.

  2. Risk factors of Streptococcus suis infection in Vietnam. A case-control study.

    Science.gov (United States)

    Nghia, Ho Dang Trung; Ho, Dang Trung Nghia; Tu, Le Thi Phuong; Le, Thi Phuong Tu; Wolbers, Marcel; Thai, Cao Quang; Cao, Quang Thai; Hoang, Nguyen Van Minh; Nguyen, Van Minh Hoang; Nga, Tran Vu Thieu; Tran, Vu Thieu Nga; Thao, Le Thi Phuong; Le, Thi Phuong Thao; Phu, Nguyen Hoan; Nguyen, Hoan Phu; Chau, Tran Thi Hong; Tran, Thi Hong Chau; Sinh, Dinh Xuan; Dinh, Xuan Sinh; Diep, To Song; To, Song Diep; Hang, Hoang Thi Thanh; Hoang, Thi Thanh Hang; Truong, Hoang; Campbell, James; Chau, Nguyen Van Vinh; Nguyen, Van Vinh Chau; Chinh, Nguyen Tran; Nguyen, Tran Chinh; Dung, Nguyen Van; Nguyen, Van Dung; Hoa, Ngo Thi; Ngo, Thi Hoa; Spratt, Brian G; Hien, Tran Tinh; Tran, Tinh Hien; Farrar, Jeremy; Schultsz, Constance

    2011-03-08

    Streptococcus suis infection, an emerging zoonosis, is an increasing public health problem across South East Asia and the most common cause of acute bacterial meningitis in adults in Vietnam. Little is known of the risk factors underlying the disease. A case-control study with appropriate hospital and matched community controls for each patient was conducted between May 2006 and June 2009. Potential risk factors were assessed using a standardized questionnaire and investigation of throat and rectal S. suis carriage in cases, controls and their pigs, using real-time PCR and culture of swab samples. We recruited 101 cases of S. suis meningitis, 303 hospital controls and 300 community controls. By multivariate analysis, risk factors identified for S. suis infection as compared to either control group included eating "high risk" dishes, including such dishes as undercooked pig blood and pig intestine (OR(1) = 2.22; 95%CI = [1.15-4.28] and OR(2) = 4.44; 95%CI = [2.15-9.15]), occupations related to pigs (OR(1) = 3.84; 95%CI = [1.32-11.11] and OR(2) = 5.52; 95%CI = [1.49-20.39]), and exposures to pigs or pork in the presence of skin injuries (OR(1) = 7.48; 95%CI = [1.97-28.44] and OR(2) = 15.96; 95%CI = [2.97-85.72]). S. suis specific DNA was detected in rectal and throat swabs of 6 patients and was cultured from 2 rectal samples, but was not detected in such samples of 1522 healthy individuals or patients without S. suis infection. This case control study, the largest prospective epidemiological assessment of this disease, has identified the most important risk factors associated with S. suis bacterial meningitis to be eating 'high risk' dishes popular in parts of Asia, occupational exposure to pigs and pig products, and preparation of pork in the presence of skin lesions. These risk factors can be addressed in public health campaigns aimed at preventing S. suis infection.

  3. Women's Views and Experiences of the Triggers for Onset of Bacterial Vaginosis and Exacerbating Factors Associated with Recurrence.

    Directory of Open Access Journals (Sweden)

    Jade Bilardi

    Full Text Available Bacterial vaginosis (BV is the most common vaginal infection affecting women of childbearing age. While the aetiology and transmissibility of BV remain unclear, there is strong evidence to suggest an association between BV and sexual activity. This study explored women's views and experiences of the triggers for BV onset and factors associated with recurrence.A descriptive, social constructionist approach was chosen as the framework for the study. Thirty five women of varying sexual orientation who had experienced recurrent BV in the past five years took part in semi-structured interviews.The majority of women predominantly reported sexual contact triggered the onset of BV and sexual and non-sexual factors precipitated recurrence. Recurrence was most commonly referred to in terms of a 'flare-up' of symptoms. The majority of women did not think BV was a sexually transmitted infection however many reported being informed this by their clinician. Single women who attributed BV onset to sex with casual partners were most likely to display self-blame tendencies and to consider changing their future sexual behaviour. Women who have sex with women (WSW were more inclined to believe their partner was responsible for the transmission of or reinfection with BV and seek partner treatment or change their sexual practices.Findings from this study strongly suggest women believe that BV onset is associated with sexual activity, concurring with epidemiological data which increasingly suggest BV may be sexually transmitted. Exacerbating factors associated with recurrence were largely heterogeneous and may reflect the fact it is difficult to determine whether recurrence is due to persistent BV or a new infection in women. There was however evidence to suggest possible transmission and reinfection among WSW, reinforcing the need for new approaches to treatment and management strategies including male and female partner treatment trials.

  4. Revisiting factors controlling methane emissions from high-Arctic tundra

    DEFF Research Database (Denmark)

    Mastepanov, M.; Sigsgaard, Charlotte; Tagesson, Håkan Torbern;

    2013-01-01

    controlling methane emission, i.e. temperature and water table position. Late in the growing season CH4 emissions were found to be very similar between the study years (except the extremely dry 2010) despite large differences in climatic factors (temperature and water table). Late-season bursts of CH4...... short-term control factors (temperature and water table). Our findings suggest the importance of multiyear studies with a continued focus on shoulder seasons in Arctic ecosystems....

  5. New Weapons to Fight Old Enemies: Novel Strategies for the (Bio)control of Bacterial Biofilms in the Food Industry

    Science.gov (United States)

    Coughlan, Laura M.; Cotter, Paul D.; Hill, Colin; Alvarez-Ordóñez, Avelino

    2016-01-01

    Biofilms are microbial communities characterized by their adhesion to solid surfaces and the production of a matrix of exopolymeric substances, consisting of polysaccharides, proteins, DNA and lipids, which surround the microorganisms lending structural integrity and a unique biochemical profile to the biofilm. Biofilm formation enhances the ability of the producer/s to persist in a given environment. Pathogenic and spoilage bacterial species capable of forming biofilms are a significant problem for the healthcare and food industries, as their biofilm-forming ability protects them from common cleaning processes and allows them to remain in the environment post-sanitation. In the food industry, persistent bacteria colonize the inside of mixing tanks, vats and tubing, compromising food safety and quality. Strategies to overcome bacterial persistence through inhibition of biofilm formation or removal of mature biofilms are therefore necessary. Current biofilm control strategies employed in the food industry (cleaning and disinfection, material selection and surface preconditioning, plasma treatment, ultrasonication, etc.), although effective to a certain point, fall short of biofilm control. Efforts have been explored, mainly with a view to their application in pharmaceutical and healthcare settings, which focus on targeting molecular determinants regulating biofilm formation. Their application to the food industry would greatly aid efforts to eradicate undesirable bacteria from food processing environments and, ultimately, from food products. These approaches, in contrast to bactericidal approaches, exert less selective pressure which in turn would reduce the likelihood of resistance development. A particularly interesting strategy targets quorum sensing systems, which regulate gene expression in response to fluctuations in cell-population density governing essential cellular processes including biofilm formation. This review article discusses the problems associated

  6. Relationship between bacterial diversity and function under biotic control: the soil pesticide degraders as a case study.

    Science.gov (United States)

    Monard, Cécile; Vandenkoornhuyse, Philippe; Le Bot, Barbara; Binet, Françoise

    2011-06-01

    In soil, the way biotic parameters impact the relationship between bacterial diversity and function is still unknown. To understand these interactions better, we used RNA-based stable-isotope probing to study the diversity of active atrazine-degrading bacteria in relation to atrazine degradation and to explore the impact of earthworm-soil engineering with respect to this relationship. Bulk soil, burrow linings and earthworm casts were incubated with (13)C-atrazine. The pollutant degradation was quantified by liquid chromatography-mass spectrometry for 8 days, whereas active atrazine degraders were identified at 2 and 8 days by sequencing the 16S ribosomal RNA in the (13)C-RNA fractions from the three soil microsites. An original diversity of atrazine degraders was found. Earthworm soil engineering greatly modified the taxonomic composition of atrazine degraders with dominance of α-, β- and γ-proteobacteria in burrow linings and of Actinobacteria in casts. Earthworm soil bioturbation increased the γ-diversity of atrazine degraders over the soil microsites generated. Atrazine degradation was enhanced in burrow linings in which primary atrazine degraders, closely related to Pelomonas aquatica, were detected only 2 days after atrazine addition. Atrazine degradation efficiency was not linearly related to the species richness of degraders but likely relied on keystone species. By enhancing soil heterogeneity, earthworms sustained high phylogenetic bacterial diversity and exerted a biotic control on the bacterial diversity-function relationships. Our findings call for future investigations to assess the ecological significance of biotic controls on the relationships between diversity and function on ecosystem properties and services (for example, soil detoxification) at larger scales.

  7. New Weapons to Fight Old Enemies: Novel Strategies for the (Bio)control of Bacterial Biofilms in the Food Industry.

    Science.gov (United States)

    Coughlan, Laura M; Cotter, Paul D; Hill, Colin; Alvarez-Ordóñez, Avelino

    2016-01-01

    Biofilms are microbial communities characterized by their adhesion to solid surfaces and the production of a matrix of exopolymeric substances, consisting of polysaccharides, proteins, DNA and lipids, which surround the microorganisms lending structural integrity and a unique biochemical profile to the biofilm. Biofilm formation enhances the ability of the producer/s to persist in a given environment. Pathogenic and spoilage bacterial species capable of forming biofilms are a significant problem for the healthcare and food industries, as their biofilm-forming ability protects them from common cleaning processes and allows them to remain in the environment post-sanitation. In the food industry, persistent bacteria colonize the inside of mixing tanks, vats and tubing, compromising food safety and quality. Strategies to overcome bacterial persistence through inhibition of biofilm formation or removal of mature biofilms are therefore necessary. Current biofilm control strategies employed in the food industry (cleaning and disinfection, material selection and surface preconditioning, plasma treatment, ultrasonication, etc.), although effective to a certain point, fall short of biofilm control. Efforts have been explored, mainly with a view to their application in pharmaceutical and healthcare settings, which focus on targeting molecular determinants regulating biofilm formation. Their application to the food industry would greatly aid efforts to eradicate undesirable bacteria from food processing environments and, ultimately, from food products. These approaches, in contrast to bactericidal approaches, exert less selective pressure which in turn would reduce the likelihood of resistance development. A particularly interesting strategy targets quorum sensing systems, which regulate gene expression in response to fluctuations in cell-population density governing essential cellular processes including biofilm formation. This review article discusses the problems associated

  8. Paediatric Crohn disease patients with stricturing behaviour exhibit ileal granulocyte–macrophage colony-stimulating factor (GM-CSF) autoantibody production and reduced neutrophil bacterial killing and GM-CSF bioactivity

    Science.gov (United States)

    Jurickova, I; Collins, M H; Chalk, C; Seese, A; Bezold, R; Lake, K; Allmen, D; Frischer, J S; Falcone, R A; Trapnell, B C; Denson, L A

    2013-01-01

    Granulocyte–macrophage colony-stimulating factor (GM-CSF) autoantibodies are associated with stricturing behaviour in Crohn disease (CD). We hypothesized that CD ileal lamina propria mononuclear cells (LPMC) would produce GM-CSF autoantibodies and peripheral blood (PB) samples would contain GM-CSF neutralizing capacity (NC). Paediatric CD and control PBMC and ileal biopsies or LPMC were isolated and cultured and GM-CSF, immunoglobulin (Ig)G and GM-CSF autoantibodies production were measured by enzyme-linked immunosorbent assay (ELISA). Basal and GM-CSF-primed neutrophil bacterial killing and signal transducer and activator of transcription 5 (STAT5) tyrosine phosphorylation (pSTAT5) were measured by flow cytometry. GM-CSF autoantibodies were enriched within total IgG for LPMC isolated from CD ileal strictures and proximal margins compared to control ileum. Neutrophil bacterial killing was reduced in CD patients compared to controls. Within CD, neutrophil GM-CSF-dependent STAT5 activation and bacterial killing were reduced as GM-CSF autoantibodies increased. GM-CSF stimulation of pSTAT5 did not vary between controls and CD patients in washed PB granulocytes in which serum was removed. However, GM-CSF stimulation of pSTAT5 was reduced in whole PB samples from CD patients. These data were used to calculate the GM-CSF NC. CD patients with GM-CSF NC greater than 25% exhibited a fourfold higher rate of stricturing behaviour and surgery. The likelihood ratio (95% confidence interval) for stricturing behaviour for patients with elevation in both GM-CSF autoantibodies and GM-CSF NC was equal to 5 (2, 11). GM-CSF autoantibodies are produced by LPMC isolated from CD ileal resection specimens and are associated with reduced neutrophil bacterial killing. CD peripheral blood contains GM-CSF NC, which is associated with increased rates of stricturing behaviour. PMID:23600834

  9. Mycobacterium leprae-induced Insulin-like Growth Factor I attenuates antimicrobial mechanisms, promoting bacterial survival in macrophages

    Science.gov (United States)

    Batista-Silva, L. R.; Rodrigues, Luciana Silva; Vivarini, Aislan de Carvalho; Costa, Fabrício da Mota Ramalho; Mattos, Katherine Antunes de; Costa, Maria Renata Sales Nogueira; Rosa, Patricia Sammarco; Toledo-Pinto, T. G.; Dias, André Alves; Moura, Danielle Fonseca; Sarno, Euzenir Nunes; Lopes, Ulisses Gazos; Pessolani, Maria Cristina Vidal

    2016-01-01

    Mycobacterium leprae (ML), the etiologic agent of leprosy, can subvert macrophage antimicrobial activity by mechanisms that remain only partially understood. In the present study, the participation of hormone insulin-like growth factor I (IGF-I) in this phenomenum was investigated. Macrophages from the dermal lesions of the disseminated multibacillary lepromatous form (LL) of leprosy expressed higher levels of IGF-I than those from the self-limited paucibacillary tuberculoid form (BT). Higher levels of IGF-I secretion by ML-infected macrophages were confirmed in ex vivo and in vitro studies. Of note, the dampening of IGF-I signaling reverted the capacity of ML-infected human and murine macrophages to produce antimicrobial molecules and promoted bacterial killing. Moreover, IGF-I was shown to inhibit the JAK/STAT1-dependent signaling pathways triggered by both mycobacteria and IFN-γ most probably through its capacity to induce the suppressor of cytokine signaling-3 (SOCS3). Finally, these in vitro findings were corroborated by in vivo observations in which higher SOCS3 expression and lower phosphorylation of STAT1 levels were found in LL versus BT dermal lesions. Altogether, our data strongly suggest that IGF-I contributes to the maintenance of a functional program in infected macrophages that suits ML persistence in the host, reinforcing a key role for IGF-I in leprosy pathogenesis. PMID:27282338

  10. Targeting c-kit receptor in neuroblastomas and colorectal cancers using stem cell factor (SCF)-based recombinant bacterial toxins.

    Science.gov (United States)

    Choudhary, Swati; Pardo, Alessa; Rosinke, Reinhard; Batra, Janendra K; Barth, Stefan; Verma, Rama S

    2016-01-01

    Autocrine activation of c-kit (KIT receptor tyrosine kinase) has been postulated to be a potent oncogenic driver in small cell lung cancer, neuroblastoma (NB), and poorly differentiated colorectal carcinoma (CRC). Although targeted therapy involving tyrosine kinase inhibitors (TKIs) such as imatinib mesylate is highly effective for gastrointestinal stromal tumor carrying V560G c-kit mutation, it does not show much potential for targeting wild-type KIT (WT-KIT). Our study demonstrates the role of stem cell factor (SCF)-based toxin conjugates for targeting WT-KIT-overexpressing malignancies such as NBs and CRCs. We constructed SCF-based recombinant bacterial toxins by genetically fusing mutated form of natural ligand SCF to receptor binding deficient forms of Diphtheria toxin (DT) or Pseudomonas exotoxin A (ETA') and evaluated their efficacy in vitro. Efficient targeting was achieved in all receptor-positive neuroblastoma (IMR-32 and SHSY5Y) and colon cancer cell lines (COLO 320DM, HCT 116, and DLD-1) but not in receptor-negative breast carcinoma cell line (MCF-7) thereby proving specificity. While dose- and time-dependent cytotoxicity was observed in both neuroblastoma cell lines, COLO 320DM and HCT 116 cells, only an anti-proliferative effect was observed in DLD-1 cells. We prove that these novel targeting agents have promising potential as KIT receptor tyrosine kinase targeting system.

  11. The role of host and microbial factors in the pathogenesis of pneumococcal bacteraemia arising from a single bacterial cell bottleneck.

    Directory of Open Access Journals (Sweden)

    Alice Gerlini

    2014-03-01

    Full Text Available The pathogenesis of bacteraemia after challenge with one million pneumococci of three isogenic variants was investigated. Sequential analyses of blood samples indicated that most episodes of bacteraemia were monoclonal events providing compelling evidence for a single bacterial cell bottleneck at the origin of invasive disease. With respect to host determinants, results identified novel properties of splenic macrophages and a role for neutrophils in early clearance of pneumococci. Concerning microbial factors, whole genome sequencing provided genetic evidence for the clonal origin of the bacteraemia and identified SNPs in distinct sub-units of F0/F1 ATPase in the majority of the ex vivo isolates. When compared to parental organisms of the inoculum, ex-vivo pneumococci with mutant alleles of the F0/F1 ATPase had acquired the capacity to grow at low pH at the cost of the capacity to grow at high pH. Although founded by a single cell, the genotypes of pneumococci in septicaemic mice indicate strong selective pressure for fitness, emphasising the within-host complexity of the pathogenesis of invasive disease.

  12. Pseudomonas fluorescens filamentous hemagglutinin, an iron-regulated protein, is an important virulence factor that modulates bacterial pathogenicity

    Directory of Open Access Journals (Sweden)

    Yuan-yuan Sun

    2016-08-01

    Full Text Available Pseudomonas fluorescens is a common bacterial pathogen to a wide range of aquaculture animals including various species of fish. In this study, we employed proteomic analysis and identified filamentous hemagglutinin (FHA as an iron-responsive protein secreted by TSS, a pathogenic P. fluorescens isolate. In vitro study showed that compared to the wild type, the fha mutant TSSfha (i exhibited a largely similar vegetative growth profile but significantly retarded in the ability of biofilm growth and producing extracellular matrix, (ii displayed no apparent flagella and motility, (iii was defective in the attachment to host cells and unable to form self-aggregation, (iv displayed markedly reduced capacity of hemagglutination and surviving in host serum. In vivo infection analysis revealed that TSSfha was significantly attenuated in the ability of dissemination in fish tissues and inducing host mortality, and that antibody blocking of the natural FHA produced by the wild type TSS impaired the infectivity of the pathogen. Furthermore, when introduced into turbot as a subunit vaccine, recombinant FHA elicited a significant protection against lethal TSS challenge. Taken together, these results indicate for the first time that P. fluorescens FHA is a key virulence factor essential to multiple biological processes associated with pathogenicity.

  13. Analysis of Campylobacter jejuni infection in the gnotobiotic piglet and genome-wide identification of bacterial factors required for infection

    Science.gov (United States)

    de Vries, Stefan P. W.; Linn, Aileen; Macleod, Kareen; MacCallum, Amanda; Hardy, Simon P.; Douce, Gill; Watson, Eleanor; Dagleish, Mark P.; Thompson, Hal; Stevenson, Andy; Kennedy, David; Baig, Abiyad; Coward, Chris; Maskell, Duncan J.; Smith, David G. E.; Grant, Andrew J.; Everest, Paul

    2017-01-01

    To investigate how Campylobacter jejuni causes the clinical symptoms of diarrhoeal disease in humans, use of a relevant animal model is essential. Such a model should mimic the human disease closely in terms of host physiology, incubation period before onset of disease, clinical signs and a comparable outcome of disease. In this study, we used a gnotobiotic piglet model to study determinants of pathogenicity of C. jejuni. In this model, C. jejuni successfully established infection and piglets developed an increased temperature with watery diarrhoea, which was caused by a leaky epithelium and reduced bile re-absorption in the intestines. Further, we assessed the C. jejuni genes required for infection of the porcine gastrointestinal tract utilising a transposon (Tn) mutant library screen. A total of 123 genes of which Tn mutants showed attenuated piglet infection were identified. Our screen highlighted a crucial role for motility and chemotaxis, as well as central metabolism. In addition, Tn mutants of 14 genes displayed enhanced piglet infection. This study gives a unique insight into the mechanisms of C. jejuni disease in terms of host physiology and contributing bacterial factors. PMID:28281647

  14. COMPLIANCE AS FACTORING BUSINESS RISK MANAGEMENT: CONTROL ASPECTS

    Directory of Open Access Journals (Sweden)

    V.K. Makarovych

    2016-03-01

    Full Text Available Indetermination of modern economy conditions and the lack of theoretical knowledge gained by domestic scientists about risk in factoring business actualize the research concerning the methodology and technique of factoring companies’ risk management. The article examines compliance which is the technology innovative for Ukrainian market of factoring risk management technologies. It is determined that the compliance is the risk management process directed to free will correspondence to state, international legislation as well as to the ethics standards accepted in the field of regulated legal relations and to the traditions of business circulation to sustain the necessary regulations and standards of market behaviour, and to consolidate the image of a factoring company. Compliance risks should be understood as the risks of missed profit or losses caused by the conflicts of interests and the discrepancy of employees’ actions to internal and external standard documents. The attention is paid to the control over the compliance. The author singles out 3 kinds of the compliance control such as institutional, operational and the compliance control over the observance of conducting business professional ethics regulations which are necessary for providing of efficient management of factoring business risks. The paper shows the organizing process of factoring business compliance control (by the development of internal standard documents, a compliance program, the foundation of compliance control subdivision, monitoring of the risks cause the choice, made by management entities of a factoring company, of the management methods of risks for their business. The development of new and improvement of existed forms of compliance control organizing process help satisfy users’ information needs and requests of the risk management factoring company department. The suggestions proposed create the grounds for the transformation and improvement of factoring

  15. Confirmatory Factor Analysis of the Work Locus of Control Scale

    Science.gov (United States)

    Oliver, Joseph E.; Jose, Paul E.; Brough, Paula

    2006-01-01

    Original formulations of the Work Locus of Control Scale (WLCS) proposed a unidimensional structure of this measure; however, more recently, evidence for a two-dimensional structure has been reported, with separate subscales for internal and external loci of control. The current study evaluates the one- and two-factor models with confirmatory…

  16. Role of environmental factors for the vertical distribution (0-1000 m) of marine bacterial communities in the NW Mediterranean Sea

    Science.gov (United States)

    Ghiglione, J. F.; Palacios, C.; Marty, J. C.; Mével, G.; Labrune, C.; Conan, P.; Pujo-Pay, M.; Garcia, N.; Goutx, M.

    2008-12-01

    Bacterioplankton plays a central role in energy and matter fluxes in the sea, yet the factors that constrain its variation in marine systems are still poorly understood. Here we use the explanatory power of direct multivariate gradient analysis to evaluate the driving forces exerted by environmental parameters on bacterial community distribution in the water column. We gathered and analysed data from a one month sampling period from the surface to 1000 m depth at the JGOFS-DYFAMED station (NW Mediterranean Sea). This station is characterized by very poor horizontal advection currents which makes it an ideal model to test hypotheses on the causes of vertical stratification of bacterial communities. Capillary electrophoresis single strand conformation polymorphism (CE-SSCP) fingerprinting profiles analyzed using multivariate statistical methods demonstrated a vertical zonation of bacterial assemblages in three layers, above, in or just below the chlorophyll maximum and deeper, that remained stable during the entire sampling period. Through the use of direct gradient multivariate ordination analyses we demonstrate that a complex array of biogeochemical parameters is the driving force behind bacterial community structure shifts in the water column. Physico-chemical parameters such as phosphate, nitrate, salinity and to a lesser extent temperature, oxygen, dissolved organic carbon and photosynthetically active radiation acted in synergy to explain bacterial assemblages changes with depth. Analysis of lipid biomarkers of organic matter sources and fates suggested that bacterial community structure in the surface layers was in part explained by lipids of chloroplast origin. Further detailed analysis of pigment-based phytoplankton diversity gave evidence of a compartmentalized influence of several phytoplankton groups on bacterial community structure in the first 150 m depth.

  17. Role of environmental factors for the vertical distribution (0–1000 m of marine bacterial communities in the NW Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    J. F. Ghiglione

    2008-12-01

    Full Text Available Bacterioplankton plays a central role in energy and matter fluxes in the sea, yet the factors that constrain its variation in marine systems are still poorly understood. Here we use the explanatory power of direct multivariate gradient analysis to evaluate the driving forces exerted by environmental parameters on bacterial community distribution in the water column. We gathered and analysed data from a one month sampling period from the surface to 1000 m depth at the JGOFS-DYFAMED station (NW Mediterranean Sea. This station is characterized by very poor horizontal advection currents which makes it an ideal model to test hypotheses on the causes of vertical stratification of bacterial communities. Capillary electrophoresis single strand conformation polymorphism (CE-SSCP fingerprinting profiles analyzed using multivariate statistical methods demonstrated a vertical zonation of bacterial assemblages in three layers, above, in or just below the chlorophyll maximum and deeper, that remained stable during the entire sampling period. Through the use of direct gradient multivariate ordination analyses we demonstrate that a complex array of biogeochemical parameters is the driving force behind bacterial community structure shifts in the water column. Physico-chemical parameters such as phosphate, nitrate, salinity and to a lesser extent temperature, oxygen, dissolved organic carbon and photosynthetically active radiation acted in synergy to explain bacterial assemblages changes with depth. Analysis of lipid biomarkers of organic matter sources and fates suggested that bacterial community structure in the surface layers was in part explained by lipids of chloroplast origin. Further detailed analysis of pigment-based phytoplankton diversity gave evidence of a compartmentalized influence of several phytoplankton groups on bacterial community structure in the first 150 m depth.

  18. Biogeochemical controls on the bacterial populations in the eastern Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    S. B. Neogi

    2011-12-01

    Full Text Available Little is known about bacterial dynamics in the oligotrophic ocean, particularly about cultivable bacteria. We examined the abundance of total and cultivable bacteria in relation to changes in biogeochemical conditions in the eastern Atlantic Ocean with special regard to Vibrio spp., a group of bacteria that can cause diseases in human and aquatic organisms. Surface, deep water and plankton (<20 μm, 20–55 μm and >55 μm samples were collected between 50° N and 24° S. Chlorophyll-a was very low (<0.3 μg l−1 in most areas of the nutrient-poor Atlantic, except at a few locations near upwelling regions. In surface water, dissolved organic carbon (DOC and nitrogen (DON concentrations were 64–95 μM C and 2–10 μM N accounting for ≥90 % and ≥76 % of total organic C and N, respectively. DOC and DON gradually decreased to ~45 μM C and <5 μM N in the bottom water. In the surface layer, culture independent total bacteria and other prokaryotes represented by 4´-6-diamidino-2-phenylindole (DAPI counts, ranged mostly between 107 and 108 cells l−1, while cultivable bacterial counts (CBC and Vibrio spp. were found at concentrations of 104–107 and 102–105 colony forming units (CFU l−1, respectively. Most bacteria (>99 % were found in the nanoplankton fraction (<20 μm, however, bacterial abundance did not correlate with suspended particulates (chlorophyll-a, particulate organic C [POC] and N [PON]. Instead, we found a highly significant correlation between bacterial abundance and temperature (p < 0.001 and a significant correlation with DOC and DON (p < 0.005 and <0.01, respectively. In comparison to CBC and DAPI-stained prokaryotes, cultivable Vibrio showed a stronger and highly significant correlation with DOC and DON (p < 0.0005 and p < 0.005, respectively. In cold waters

  19. Bacterial Abscess Formation Is Controlled by the Stringent Stress Response and Can Be Targeted Therapeutically.

    Science.gov (United States)

    Mansour, Sarah C; Pletzer, Daniel; de la Fuente-Núñez, César; Kim, Paul; Cheung, Gordon Y C; Joo, Hwang-Soo; Otto, Michael; Hancock, Robert E W

    2016-10-01

    Cutaneous abscess infections are difficult to treat with current therapies and alternatives to conventional antibiotics are needed. Understanding the regulatory mechanisms that govern abscess pathology should reveal therapeutic interventions for these recalcitrant infections. Here we demonstrated that the stringent stress response employed by bacteria to cope and adapt to environmental stressors was essential for the formation of lesions, but not bacterial growth, in a methicillin resistant Staphylococcus aureus (MRSA) cutaneous abscess mouse model. To pharmacologically confirm the role of the stringent response in abscess formation, a cationic peptide that causes rapid degradation of the stringent response mediator, guanosine tetraphosphate (ppGpp), was employed. The therapeutic application of this peptide strongly inhibited lesion formation in mice infected with Gram-positive MRSA and Gram-negative Pseudomonas aeruginosa. Overall, we provide insights into the mechanisms governing abscess formation and a paradigm for treating multidrug resistant cutaneous abscesses.

  20. Lysis-deficient phages as novel therapeutic agents for controlling bacterial infection

    Directory of Open Access Journals (Sweden)

    Kempashanaiah Nanjundappa

    2011-08-01

    Full Text Available Abstract Background Interest in phage therapy has grown over the past decade due to the rapid emergence of antibiotic resistance in bacterial pathogens. However, the use of bacteriophages for therapeutic purposes has raised concerns over the potential for immune response, rapid toxin release by the lytic action of phages, and difficulty in dose determination in clinical situations. A phage that kills the target cell but is incapable of host cell lysis would alleviate these concerns without compromising efficacy. Results We developed a recombinant lysis-deficient Staphylococcus aureus phage P954, in which the endolysin gene was rendered nonfunctional by insertional inactivation. P954, a temperate phage, was lysogenized in S. aureus strain RN4220. The native endolysin gene on the prophage was replaced with an endolysin gene disrupted by the chloramphenicol acetyl transferase (cat gene through homologous recombination using a plasmid construct. Lysogens carrying the recombinant phage were detected by growth in presence of chloramphenicol. Induction of the recombinant prophage did not result in host cell lysis, and the phage progeny were released by cell lysis with glass beads. The recombinant phage retained the endolysin-deficient genotype and formed plaques only when endolysin was supplemented. The host range of the recombinant phage was the same as that of the parent phage. To test the in vivo efficacy of the recombinant endolysin-deficient phage, immunocompromised mice were challenged with pathogenic S. aureus at a dose that results in 80% mortality (LD80. Treatment with the endolysin-deficient phage rescued mice from the fatal S. aureus infection. Conclusions A recombinant endolysin-deficient staphylococcal phage has been developed that is lethal to methicillin-resistant S. aureus without causing bacterial cell lysis. The phage was able to multiply in lytic mode utilizing a heterologous endolysin expressed from a plasmid in the propagation host

  1. A new Polyherbal formulation to control bacterial enteritis in poultry: a case study in Salmonella enteritidis induced experimental model

    Directory of Open Access Journals (Sweden)

    K.K.Baishya

    Full Text Available An experiemental study was conducted in day old 150 VenCobb chicks to evaluate efficacy of polyherbal formulation in induced bacterial enteritis with Salmonella enteritidis. Birds were randomly divided into three groups: negative control, infected and untreated control & prophylactically treated group with AV/ADC/16 (14th-28th days. Salmonella infection was induced on day 21st. A significant decrease in overall growth, productivity, feed conversion and mortality was evident in untreated infected group in addition to severity of clinical signs. However, prophylactic administration of herbal formulation reduced mortality and clinical symptoms were mild to negligible. No negative effect on growth & performance was observed in treated group III. [Veterinary World 2008; 1(11.000: 333-334

  2. Human factors survey of advanced instrumentation and controls

    Energy Technology Data Exchange (ETDEWEB)

    Carter, R.J.

    1989-01-01

    A survey oriented towards identifying the human factors issues in regard to the use of advanced instrumentation and controls (I C) in the nuclear industry was conducted. A number of United States (US) and Canadian nuclear vendors and utilities were participants in the survey. Human factors items, subsumed under the categories of computer-generated displays (CGD), controls, organizational support, training, and related topics, were discussed. The survey found the industry to be concerned about the human factors issues related to the implementation of advanced I C. Fifteen potential human factors problems were identified. They include: the need for an advanced I C guideline equivalent to NUREG-0700; a role change in the control room from operator to supervisor; information overload; adequacy of existing training technology for advanced I C; and operator acceptance and trust. 11 refs., 1 tab.

  3. Soft Controls: Technical Basis and Human Factors Review Guidance

    Science.gov (United States)

    2000-03-01

    Controlling Office is (insert controlling DoD office). NUREG /CR-6635 BNL- NUREG -52565 Soft Controls: Technical Basis and Human Factors Review Guidance...DC 20555-0001 AVAILABILITY NOTICE Availability of Reference Materials Cited in NRC Publications NRC publications in the NUREG series, NRC regu...Technical Information Service Springfield, VA 22161 -0002 <http://www.ntis.gov> 1 -800-553-6847 or locally 703-605-6000 The NUREG series

  4. Bacterial antagonists of fungal pathogens also control root-knot nematodes by induced systemic resistance of tomato plants.

    Science.gov (United States)

    Adam, Mohamed; Heuer, Holger; Hallmann, Johannes

    2014-01-01

    The potential of bacterial antagonists of fungal pathogens to control the root-knot nematode Meloidogyne incognita was investigated under greenhouse conditions. Treatment of tomato seeds with several strains significantly reduced the numbers of galls and egg masses compared with the untreated control. Best performed Bacillus subtilis isolates Sb4-23, Mc5-Re2, and Mc2-Re2, which were further studied for their mode of action with regard to direct effects by bacterial metabolites or repellents, and plant mediated effects. Drenching of soil with culture supernatants significantly reduced the number of egg masses produced by M. incognita on tomato by up to 62% compared to the control without culture supernatant. Repellence of juveniles by the antagonists was shown in a linked twin-pot set-up, where a majority of juveniles penetrated roots on the side without inoculated antagonists. All tested biocontrol strains induced systemic resistance against M. incognita in tomato, as revealed in a split-root system where the bacteria and the nematodes were inoculated at spatially separated roots of the same plant. This reduced the production of egg masses by up to 51%, while inoculation of bacteria and nematodes in the same pot had only a minor additive effect on suppression of M. incognita compared to induced systemic resistance alone. Therefore, the plant mediated effect was the major reason for antagonism rather than direct mechanisms. In conclusion, the bacteria known for their antagonistic potential against fungal pathogens also suppressed M. incognita. Such "multi-purpose" bacteria might provide new options for control strategies, especially with respect to nematode-fungus disease complexes that cause synergistic yield losses.

  5. Bacterial antagonists of fungal pathogens also control root-knot nematodes by induced systemic resistance of tomato plants.

    Directory of Open Access Journals (Sweden)

    Mohamed Adam

    Full Text Available The potential of bacterial antagonists of fungal pathogens to control the root-knot nematode Meloidogyne incognita was investigated under greenhouse conditions. Treatment of tomato seeds with several strains significantly reduced the numbers of galls and egg masses compared with the untreated control. Best performed Bacillus subtilis isolates Sb4-23, Mc5-Re2, and Mc2-Re2, which were further studied for their mode of action with regard to direct effects by bacterial metabolites or repellents, and plant mediated effects. Drenching of soil with culture supernatants significantly reduced the number of egg masses produced by M. incognita on tomato by up to 62% compared to the control without culture supernatant. Repellence of juveniles by the antagonists was shown in a linked twin-pot set-up, where a majority of juveniles penetrated roots on the side without inoculated antagonists. All tested biocontrol strains induced systemic resistance against M. incognita in tomato, as revealed in a split-root system where the bacteria and the nematodes were inoculated at spatially separated roots of the same plant. This reduced the production of egg masses by up to 51%, while inoculation of bacteria and nematodes in the same pot had only a minor additive effect on suppression of M. incognita compared to induced systemic resistance alone. Therefore, the plant mediated effect was the major reason for antagonism rather than direct mechanisms. In conclusion, the bacteria known for their antagonistic potential against fungal pathogens also suppressed M. incognita. Such "multi-purpose" bacteria might provide new options for control strategies, especially with respect to nematode-fungus disease complexes that cause synergistic yield losses.

  6. Aircraft Loss of Control Causal Factors and Mitigation Challenges

    Science.gov (United States)

    Jacobson, Steven R.

    2010-01-01

    Loss of control is the leading cause of jet fatalities worldwide. Aside from their frequency of occurrence, accidents resulting from loss of aircraft control seize the public s attention by yielding a large number of fatalities in a single event. In response to the rising threat to aviation safety, the NASA Aviation Safety Program has conducted a study of the loss of control problem. This study gathered four types of information pertaining to loss of control accidents: (1) statistical data; (2) individual accident reports that cite loss of control as a contributing factor; (3) previous meta-analyses of loss of control accidents; and (4) inputs solicited from aircraft manufacturers, air carriers, researchers, and other industry stakeholders. Using these information resources, the study team identified the causal factors that were cited in the greatest number of loss of control accidents, and which were emphasized most by industry stakeholders. This report describes the study approach, the key causal factors for aircraft loss of control, and recommended mitigation strategies to make near-term impacts, mid-term impacts, and Next Generation Air Transportation System impacts on the loss of control accident statistics

  7. Selectivity and self-assembly in the control of a bacterial toxin by an antitoxic noncoding RNA pseudoknot.

    Science.gov (United States)

    Short, Francesca L; Pei, Xue Y; Blower, Tim R; Ong, Shue-Li; Fineran, Peter C; Luisi, Ben F; Salmond, George P C

    2013-01-15

    Bacterial small RNAs perform numerous regulatory roles, including acting as antitoxic components in toxin-antitoxin systems. In type III toxin-antitoxin systems, small processed RNAs directly antagonize their toxin protein partners, and in the systems characterized the toxin and antitoxin components together form a trimeric assembly. In the present study, we sought to define how the RNA antitoxin, ToxI, inhibits its potentially lethal protein partner, ToxN. We show through cross-inhibition experiments with the ToxIN systems from Pectobacterium atrosepticum (ToxIN(Pa)) and Bacillus thuringiensis (ToxIN(Bt)) that ToxI RNAs are highly selective enzyme inhibitors. Both systems have an "addictive" plasmid maintenance phenotype. We demonstrate that ToxI(Pa) can inhibit ToxN(Pa) in vitro both in its processed form and as a repetitive precursor RNA, and this inhibition is linked to the self-assembly of the trimeric complex. Inhibition and self-assembly are both mediated entirely by the ToxI(Pa) RNA, with no requirement for cellular factors or exogenous energy. Finally, we explain the origins of ToxI antitoxin selectivity through our crystal structure of the ToxIN(Bt) complex. Our results show how a processed RNA pseudoknot can inhibit a deleterious protein with exquisite molecular specificity and how these self-contained and addictive RNA-protein pairs can confer different adaptive benefits in their bacterial hosts.

  8. Specific detection of common pathogens of acute bacterial meningitis using an internally controlled tetraplex-PCR assay.

    Science.gov (United States)

    Farahani, Hamidreza; Ghaznavi-Rad, Ehsanollah; Mondanizadeh, Mahdieh; MirabSamiee, Siamak; Khansarinejad, Behzad

    2016-08-01

    Accurate and timely diagnosis of acute bacterial meningitis is critical for antimicrobial treatment of patients. Although PCR-based methods have been widely used for the diagnosis of acute meningitis caused by bacterial pathogens, the main disadvantage of these methods is their high cost. This disadvantage has hampered the widespread use of molecular assays in many developing countries. The application of multiplex assays and "in-house" protocols are two main approaches that can reduce the overall cost of a molecular test. In the present study, an internally controlled tetraplex-PCR was developed and validated for the specific detection of Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae in cerebrospinal fluid (CSF) samples. The analysis of a panel of other human pathogens showed no cross-reactivity in the assay. The analytical sensitivity of the in-house assay was 792.3 copies/ml, when all three bacteria were presentin the specimens. This value was calculated as 444.5, 283.7, 127.8 copies/ml when only S. pneumoniae, N. meningitidis and H. influenzae, respectively, were present. To demonstrate the diagnostic performance of the assay, a total of 150 archival CSF samples were tested and compared with a commercial multiplex real-time PCR kit. A diagnostic sensitivity of 92.8% and a specificity of 95.1% were determined for the present tetraplex-PCR assay. The results indicate that the established method is sensitive, specific and cost-effective, and can be used particularly in situations where the high cost of commercial kits prevents the use of molecular methods for the diagnosis of bacterial meningitis.

  9. Investigation of critical inter-related factors affecting the efficacy of pulsed light for inactivating clinically relevant bacterial pathogens.

    Science.gov (United States)

    Farrell, H P; Garvey, M; Cormican, M; Laffey, J G; Rowan, N J

    2010-05-01

    To investigate critical electrical and biological factors governing the efficacy of pulsed light (PL) for the in vitro inactivation of bacteria isolated from the clinical environment. Development of this alternative PL decontamination approach is timely, as the incidence of health care-related infections remains unacceptably high. Predetermined cell numbers of clinically relevant Gram-positive and Gram-negative bacteria were inoculated separately on agar plates and were flashed with pulses of broad-spectrum light under varying operating conditions, and their inactivation measured. Significant differences in inactivation largely occurred depending on the level of the applied lamp discharge energy (range 3.2-20 J per pulse), the amount of pulsing applied (range 0-60 pulses) and the distance between light source and treatment surface (range 8-20 cm) used. Greater decontamination levels were achieved using a combination of higher lamp discharge energies, increased number of pulses and shorter distances between treatment surface and the xenon light source. Levels of microbial sensitivity also varied depending on the population type, size and age of cultures treated. Production of pigment pyocynanin and alginate slime in mucoid strains of Pseudomonas aeruginosa afforded some protection against lethal action of PL; however, this was evident only by using a combination of reduced amount of pulsing at the lower lamp discharge energies tested. A clear pattern was observed where Gram-positive bacterial pathogens were more resistant to cidal effects of PL compared to Gram negatives. While negligible photoreactivation of PL-treated bacterial strains occurred after full pulsing regimes at the different lamp discharge energies tested, some repair was evident when using a combination of reduced pulsing at the lower lamp discharge energies. Strains harbouring genes for multiple resistances to antibiotics were not significantly more resistant to PL treatments. Slight temperature

  10. Characteristics and Predisposing Factors of Bacterial Corneal Ulcer in the National Eye Center, Cicendo Eye Hospital, Bandung from January to December 2011

    Directory of Open Access Journals (Sweden)

    Astrid Maharani Putri

    2015-09-01

    Full Text Available Background: Corneal ulcer is an emergency condition in ophthalmology, causing visual impairment, mostly by bacterial infection with rapid pathogenesis. The aim of this study was to discover the characteristics of bacterial corneal ulcer patients in the National Eye Center, Cicendo Eye Hospital, Bandung. Methods: A total of 99 medical records consisted of patients diagnosed with bacterial corneal ulcer were selected in this descriptive study. The clinical patterns and predisposing factors of the patients were analyzed. The study also identified the pathogenic bacteria of the cases. This study was carried out in the National Eye Center, Cicendo Eye Hospital, Bandung from January to December 2011 Clinical patterns. The collected data were analyzed and presented in frequency tabulation. Results: The male to female ratio was 2:1, with the average age of 44.4 years. The most common presenting symptom was eye pain (70.7%. Most patients came with decreased visual acuity that was categorized as (near- blindness (78.8% and the location of the ulcer was in central area of the cornea (56.5%. The most common predisposing factor was ocular trauma (74.7% that was caused by exposed to plants. Single-bacterial infection (67.7% was predominant, with 56 cases (56.6% of Gram-positive cocci infection. Conclusions: Bacterial corneal ulcer contributes to 48.8% of all microbial corneal ulcers. Most patients came with mild condition, centralized location, and poor visual function. The common predisposing factor was trauma associated with exposed to plants.

  11. Biological Control of Bacterial Fruit Blotch of Watermelon Pathogen (Acidovorax citrulli) with Rhizosphere Associated Bacteria.

    Science.gov (United States)

    Adhikari, Mahesh; Yadav, Dil Raj; Kim, Sang Woo; Um, Young Hyun; Kim, Hyun Seung; Lee, Seong Chan; Song, Jeong Young; Kim, Hong Gi; Lee, Youn Su

    2017-04-01

    Bacterial fruit blotch (BFB), which is caused by Acidovorax citrulli, is a serious threat to watermelon growers around the world. The present study was conducted to screen effective rhizobacterial isolates against 35 different A. citrulli isolates and determine their efficacy on BFB and growth parameters of watermelon. Two rhizobacterial isolates viz. Paenibacillus polymyxa (SN-22), Sinomonas atrocyanea (NSB-27) showed high inhibitory activity in the preliminary screening and were further evaluated for their effect on BFB and growth parameters of three different watermelon varieties under greenhouse conditions. The greenhouse experiment result revealed that SN-22 and NSB-27 significantly reduced BFB and had significant stimulatory effect on total chlorophyll content, plant height, total fresh weight and total dry weight compared to uninoculated plants across the tested three watermelon varieties. Analysis of the 16S ribosomal RNA (rRNA) sequences revealed that strains SN-22 belong to P. polymyxa and NSB-27 to S. atrocyanea with the bootstrap value of 99% and 98%, respectively. The isolates SN-22 and NSB-27 were tested for antagonistic and PGP traits. The result showed that the tested isolates produced siderophore, hydrolytic enzymes (protease and cellulose), chitinase, starch hydrolytic enzymes and they showed phosphate as well as zinc solubilizing capacity. This is the first report of P. polymyxa (SN-22) and S. atrocyanea (NSB-27) as biocontrol-plant growth promoting rhizobacteria on watermelon.

  12. IL-22 Controls Iron-Dependent Nutritional Immunity Against Systemic Bacterial Infections

    Science.gov (United States)

    Sakamoto, Kei; Kim, Yun-Gi; Hara, Hideki; Kamada, Nobuhiko; Caballero-Flores, Gustavo; Tolosano, Emanuela; Soares, Miguel P.; Puente, José L.; Inohara, Naohiro; Núñez, Gabriel

    2017-01-01

    Host immunity limits iron availability to pathogenic bacteria, but whether immunity limits pathogenic bacteria from accessing host heme, the major source of iron in the body, remains unclear. Using Citrobacter rodentium, a mouse enteric pathogen and Escherichia coli, a major cause of sepsis in humans as models, we find that interleukin-22, a cytokine best known for its ability to promote epithelial barrier function, also suppresses the systemic growth of bacteria by limiting iron availability to the pathogen. Using an unbiased proteomic approach to understand the mechanistic basis of IL-22 dependent iron retention in the host, we have identified that IL-22 induces the production of the plasma hemoglobin scavenger haptoglobin and heme scavenger hemopexin. Moreover, the anti-microbial effect of IL-22 depends on the induction of hemopexin expression, while haptogloblin is dispensable. Impaired pathogen clearance in infected Il22−/− mice was restored by hemopexin administration and hemopexin-deficient mice had increased pathogen loads after infection. These studies reveal a previously unrecognized host defense mechanism regulated by IL-22 that relies on the induction of hemopexin to limit heme availability to bacteria leading to suppression of bacterial growth during systemic infections. PMID:28286877

  13. Biological Control of Bacterial Fruit Blotch of Watermelon Pathogen (Acidovorax citrulli) with Rhizosphere Associated Bacteria

    Science.gov (United States)

    Adhikari, Mahesh; Yadav, Dil Raj; Kim, Sang Woo; Um, Young Hyun; Kim, Hyun Seung; Lee, Seong Chan; Song, Jeong Young; Kim, Hong Gi; Lee, Youn Su

    2017-01-01

    Bacterial fruit blotch (BFB), which is caused by Acidovorax citrulli, is a serious threat to watermelon growers around the world. The present study was conducted to screen effective rhizobacterial isolates against 35 different A. citrulli isolates and determine their efficacy on BFB and growth parameters of watermelon. Two rhizobacterial isolates viz. Paenibacillus polymyxa (SN-22), Sinomonas atrocyanea (NSB-27) showed high inhibitory activity in the preliminary screening and were further evaluated for their effect on BFB and growth parameters of three different watermelon varieties under greenhouse conditions. The greenhouse experiment result revealed that SN-22 and NSB-27 significantly reduced BFB and had significant stimulatory effect on total chlorophyll content, plant height, total fresh weight and total dry weight compared to uninoculated plants across the tested three watermelon varieties. Analysis of the 16S ribosomal RNA (rRNA) sequences revealed that strains SN-22 belong to P. polymyxa and NSB-27 to S. atrocyanea with the bootstrap value of 99% and 98%, respectively. The isolates SN-22 and NSB-27 were tested for antagonistic and PGP traits. The result showed that the tested isolates produced siderophore, hydrolytic enzymes (protease and cellulose), chitinase, starch hydrolytic enzymes and they showed phosphate as well as zinc solubilizing capacity. This is the first report of P. polymyxa (SN-22) and S. atrocyanea (NSB-27) as biocontrol-plant growth promoting rhizobacteria on watermelon. PMID:28381964

  14. Two-Component Signaling System VgrRS Directly Senses Extracytoplasmic and Intracellular Iron to Control Bacterial Adaptation under Iron Depleted Stress.

    Directory of Open Access Journals (Sweden)

    Li Wang

    2016-12-01

    Full Text Available Both iron starvation and excess are detrimental to cellular life, especially for animal and plant pathogens since they always live in iron-limited environments produced by host immune responses. However, how organisms sense and respond to iron is incompletely understood. Herein, we reveal that in the phytopathogenic bacterium Xanthomonas campestris pv. campestris, VgrS (also named ColS is a membrane-bound receptor histidine kinase that senses extracytoplasmic iron limitation in the periplasm, while its cognate response regulator, VgrR (ColR, detects intracellular iron excess. Under iron-depleted conditions, dissociation of Fe3+ from the periplasmic sensor region of VgrS activates the VgrS autophosphorylation and subsequent phosphotransfer to VgrR, an OmpR-family transcription factor that regulates bacterial responses to take up iron. VgrR-VgrS regulon and the consensus DNA binding motif of the transcription factor VgrR were dissected by comparative proteomic and ChIP-seq analyses, which revealed that in reacting to iron-depleted environments, VgrR directly or indirectly controls the expressions of hundreds of genes that are involved in various physiological cascades, especially those associated with iron-uptake. Among them, we demonstrated that the phosphorylated VgrR tightly represses the transcription of a special TonB-dependent receptor gene, tdvA. This regulation is a critical prerequisite for efficient iron uptake and bacterial virulence since activation of tdvA transcription is detrimental to these processes. When the intracellular iron accumulates, the VgrR-Fe2+ interaction dissociates not only the binding between VgrR and the tdvA promoter, but also the interaction between VgrR and VgrS. This relieves the repression in tdvA transcription to impede continuous iron uptake and avoids possible toxic effects of excessive iron accumulation. Our results revealed a signaling system that directly senses both extracytoplasmic and intracellular

  15. Prevalence, risk factors, and major bacterial causes of camel mastitis in Borana Zone, Oromia Regional State, Ethiopia.

    Science.gov (United States)

    Regassa, Alemayehu; Golicha, Gelma; Tesfaye, Dawit; Abunna, Fufa; Megersa, Bekele

    2013-10-01

    A cross-sectional study was carried out from November 2010 up to April 2011 to estimate mastitis prevalence and associated risk factors and to assess its bacterial causes in traditionally managed camels in Borana Zone, Southern Ethiopia. Thus, 348 lactating camels were examined clinically, and subclinical cases were checked with California mastitis test (CMT). The overall prevalence of mastitis was 44.8 % (156/348), comprising clinical (19, 5.4 %) and subclinical (137, 39.4 %) cases. The quarter level prevalence of mastitis was 24.0 % (334/1,392). Of the total 1,392 examined teats, 30 were blind, and hence, from the 1,362 non-blind CMT-examined teats, 22.3 % (304/1,362) were CMT positive. Of the 304 CMT-positive samples, 264 were culture positive (197 Gram-positive, 41 Gram-negative, and 26 mixed isolates), and 40 were culture negative. The prevalence of Staphylococcus aureus was found to be the highest at both the animal (12.8 %, 39/304) and quarter level (2.9 %, 39/1,362). Regression analysis revealed higher likelihood of mastitis occurrence among camels from Dharito (OR = 3.4, 95 % confidence interval (CI) = 1.8, 6.4), Gagna (OR = 3.4, 95 % CI = 1.8, 6.5), and Haro Bake (OR = 2.6, 95 % CI = 1.3, 5.1) than camels from Surupha. Likewise, there was higher chance of mastitis occurrence among camels at the early lactation stage (OR = 2.3, 95 % CI = 1.1, 4.6) and camels with udder/teat lesions (OR = 13.7, 95 % CI = 1.7, 109.4) than among camels at late lactation stage and camels with healthy udder/teats, respectively. In conclusion, this study reveals the current status of camel mastitis in Southern Ethiopia.

  16. Staphylococcal Ecb protein and host complement regulator factor H enhance functions of each other in bacterial immune evasion.

    Science.gov (United States)

    Amdahl, Hanne; Jongerius, Ilse; Meri, Taru; Pasanen, Tanja; Hyvärinen, Satu; Haapasalo, Karita; van Strijp, Jos A; Rooijakkers, Suzan H; Jokiranta, T Sakari

    2013-08-15

    Staphylococcus aureus is a major human pathogen causing more than a tenth of all septicemia cases and often superficial and deep infections in various tissues. One of the immune evasion strategies of S. aureus is to secrete proteins that bind to the central complement opsonin C3b. One of these, extracellular complement binding protein (Ecb), is known to interfere directly with functions of C3b. Because C3b is also the target of the physiological plasma complement regulator, factor H (FH), we studied the effect of Ecb on the complement regulatory functions of FH. We show that Ecb enhances acquisition of FH from serum onto staphylococcal surfaces. Ecb and FH enhance mutual binding to C3b and also the function of each other in downregulating complement activation. Both Ecb and the C-terminal domains 19-20 of FH bind to the C3d part of C3b. We show that the mutual enhancing effect of Ecb and FH on binding to C3b depends on binding of the FH domain 19 to the C3d part of C3b next to the binding site of Ecb on C3d. Our results show that Ecb, FH, and C3b form a tripartite complex. Upon exposure of serum-sensitive Haemophilus influenzae to human serum, Ecb protected the bacteria, and this effect was enhanced by the addition of the C-terminal domains 19-20 of FH. This finding indicates that the tripartite complex formation could give additional protection to bacteria and that S. aureus is thereby able to use host FH and bacterial Ecb in a concerted action to eliminate C3b at the site of infection.

  17. Human Factors Engineering Aspects of Modifications in Control Room Modernization

    Energy Technology Data Exchange (ETDEWEB)

    Hugo, Jacques; Clefton, Gordon; Joe, Jeffrey

    2017-06-01

    This report describes the basic aspects of control room modernization projects in the U.S. nuclear industry and the need for supplementary guidance on the integration of human factors considerations into the licensing and regulatory aspects of digital upgrades. The report pays specific attention to the integration of principles described in NUREG-0711 (Human Factors Engineering Program Review Model) and how supplementary guidance can help to raise general awareness in the industry regarding the complexities of control room modernization projects created by many interdependent regulations, standards and guidelines. The report also describes how human factors engineering principles and methods provided by various resources and international standards can help in navigating through the process of licensing digital upgrades. In particular, the integration of human factors engineering guidance and requirements into the process of licensing digital upgrades can help reduce uncertainty related to development of technical bases for digital upgrades that will avoid the introduction of new failure modes.

  18. Viral control of bacterial biodiversity - Evidence from a nutrient enriched mesocosm experiment

    DEFF Research Database (Denmark)

    Sandaa, R.-A.; Gómez-Consarnau, L.; Pinhassi, J.;

    2009-01-01

    We demonstrate here results showing that bottom-up and top-down control mechanisms can operate simultaneously and in concert in marine microbial food webs, controlling prokaryote diversity by a combination of viral lysis and substrate limitation. Models in microbial ecology predict that a shift i...

  19. [Viral-bacterial-fungal associations in chronic tonsillitis in children].

    Science.gov (United States)

    Gudima, I A; Vasil'eva, L I; Bragina, L E; Suchkov, I Iu

    2001-01-01

    The microflora of palatal tonsils was studied in 84 children with chronic tonsillitis in comparison with that in the control group of 38 healthy children. In most of the sick children viral-bacterial and less frequently viral-bacterial-fungal associations were detected with the prevalence of reo- and adenoviruses, Epstein-Barr viruses, coagulase negative staphylococci and Staphylococcus aureus, as well as peptostreptococci. Adhesive activity and persistence factors among the main bacterial pathogens were shown to be widely prevalent. The depth of the lesion of tonsillar tissue by the infective agents of bacterial and fungal nature, as well as their persistence potential, depended on the taxonomic position of these microorganisms.

  20. Rates of gyrase supercoiling and transcription elongation control supercoil density in a bacterial chromosome.

    Directory of Open Access Journals (Sweden)

    Nikolay Rovinskiy

    Full Text Available Gyrase catalyzes negative supercoiling of DNA in an ATP-dependent reaction that helps condense bacterial chromosomes into a compact interwound "nucleoid." The supercoil density (σ of prokaryotic DNA occurs in two forms. Diffusible supercoil density (σ(D moves freely around the chromosome in 10 kb domains, and constrained supercoil density (σ(C results from binding abundant proteins that bend, loop, or unwind DNA at many sites. Diffusible and constrained supercoils contribute roughly equally to the total in vivo negative supercoil density of WT cells, so σ = σ(C+σ(D. Unexpectedly, Escherichia coli chromosomes have a 15% higher level of σ compared to Salmonella enterica. To decipher critical mechanisms that can change diffusible supercoil density of chromosomes, we analyzed strains of Salmonella using a 9 kb "supercoil sensor" inserted at ten positions around the genome. The sensor contains a complete Lac operon flanked by directly repeated resolvase binding sites, and the sensor can monitor both supercoil density and transcription elongation rates in WT and mutant strains. RNA transcription caused (- supercoiling to increase upstream and decrease downstream of highly expressed genes. Excess upstream supercoiling was relaxed by Topo I, and gyrase replenished downstream supercoil losses to maintain an equilibrium state. Strains with TS gyrase mutations growing at permissive temperature exhibited significant supercoil losses varying from 30% of WT levels to a total loss of σ(D at most chromosome locations. Supercoil losses were influenced by transcription because addition of rifampicin (Rif caused supercoil density to rebound throughout the chromosome. Gyrase mutants that caused dramatic supercoil losses also reduced the transcription elongation rates throughout the genome. The observed link between RNA polymerase elongation speed and gyrase turnover suggests that bacteria with fast growth rates may generate higher supercoil densities

  1. Quality control of the sheep bacterial artificial chromosome library, CHORI-243

    Directory of Open Access Journals (Sweden)

    Kirkness Ewen F

    2010-12-01

    Full Text Available Abstract Background The sheep CHORI-243 bacterial artificial chromosome (BAC library is being used in the construction of the virtual sheep genome, the sequencing and construction of the actual sheep genome assembly and as a source of DNA for regions of the genome of biological interest. The objective of our study is to assess the integrity of the clones and plates which make up the CHORI-243 library using the virtual sheep genome. Findings A series of analyses were undertaken based on the mapping the sheep BAC-end sequences (BESs to the virtual sheep genome. Overall, very few plate specific biases were identified, with only three of the 528 plates in the library significantly affected. The analysis of the number of tail-to-tail (concordant BACs on the plates identified a number of plates with lower than average numbers of such BACs. For plates 198 and 213 a partial swap of the BESs determined with one of the two primers appear to have occurred. A third plate, 341, also with a significant deficit in tail-to-tail BACs, appeared to contain a substantial number of sequences determined from contaminating eubacterial 16 S rRNA DNA. Additionally a small number of eubacterial 16 S rRNA DNA sequences were present on two other plates, 111 and 338, in the library. Conclusions The comparative genomic approach can be used to assess BAC library integrity in the absence of fingerprinting. The sequences of the sheep CHORI-243 library BACs have high integrity, especially with the corrections detailed above. The library represents a high quality resource for use by the sheep genomics community.

  2. Randomized-controlled trial of rifaximin versus norfloxacin for secondary prophylaxis of spontaneous bacterial peritonitis.

    Science.gov (United States)

    Elfert, Asem; Abo Ali, Lobna; Soliman, Samah; Ibrahim, Shimaa; Abd-Elsalam, Sherief

    2016-12-01

    Spontaneous bacterial peritonitis (SBP) is a serious complication of liver cirrhosis with a high recurrence rate and a marked increase in mortality. Norfloxacin is used widely for the secondary prophylaxis of SBP; however, its extensive long-term use has led to an increase in the incidence of quinolone-resistant and Gram-positive SBP. Rifaximin is a nonabsorbable broad-spectrum antibiotic and does not appear to promote emergence of resistance. The aim of this study was to compare the safety and efficacy of rifaximin versus norfloxacin for the secondary prevention of SBP in patients with liver cirrhosis and ascites. Two hundred and sixty two cirrhotic patients with ascites and a previous episode of SBP were assigned randomly to receive either 1200 mg rifaximin or 400 mg of norfloxacin daily for 6 months. All patients were monitored clinically each month and with ascitic fluid examination at the end of 2 and 6 months if not clinically suspected of recurrence earlier. Recurrence of SBP was significantly lower in the rifaximin group (3.88 vs. 14.13%) compared with the norfloxacin group (P=0.04). The mortality rate was significantly decreased in the rifaximin group (13.74 vs. 24.43%) compared with the norfloxacin group (P=0.044). The causes of death between the two groups did not show a significant difference (P=0.377), but encephalopathy-related deaths were three folds higher in the norfloxacin group. There was a significant decrease in the side effects in the rifaximin group versus the norfloxacin group (P=0.033). Rifaximin was more effective than norfloxacin in the secondary prevention of SBP. Encephalopathy-related mortality and side effects were fewer in the rifaximin group.

  3. Factors influencing variation of bulk milk antibiotic residue occurrence, somatic cell count, and total bacterial count in dairy sheep flocks.

    Science.gov (United States)

    Gonzalo, C; Carriedo, J A; García-Jimeno, M C; Pérez-Bilbao, M; de la Fuente, L F

    2010-04-01

    To study the variations of bulk tank milk variables in dairy ewe flocks and to identify the main target practices and flock groups to improve milk quality and safety, a total of 71,228 records of antibiotic residue (AR) and milk yield and 68,781 records of somatic cell count (SCC) and total bacterial count (TBC) were obtained over 5 yr from the same 209 dairy ewe flocks of the Assaf breed belonging to the Consortium for Ovine Promotion of Castilla-León (Spain). Based on a logistic regression model, year, month, semester, SCC, TBC, dry therapy, and milk yield significantly contributed to AR variation. High SCC was associated with increased AR violations. When antibiotic dry therapy was implemented, AR occurrence was higher than when this practice was not used. A polynomial monthly distribution throughout the year was observed for AR occurrence; the highest values were in autumn, coinciding with low milk yields per flock. Yearly occurrences drastically diminished from 2004 (1.36%) to 2008 (0.30%), probably as a result of effective educational programs. The mixed-model ANOVA of factors influencing variation in SCC and TBC indicated that year, month, AR, dry therapy group, milking type, and year interactions were significant variation factors for SCC and TBC; mathematical model accounted for 74.1 and 35.4% of total variance for each variable, respectively. Differences in management and hygiene practice caused significant SCC and TBC variations among flocks and within flocks throughout the 5-yr study. Over time, continuously dry treated flocks showed lower logSCC (5.80) and logTBC (4.92) than untreated (6.10 and 5.18, respectively) or discontinuously dry treated (6.01 and 5.05, respectively) flocks. Continuously dry treated flocks had lower AR occurrences than did discontinuously dry treated flocks. As a whole, AR occurrence and SCC and TBC bulk tank milk variables can be used for monitoring mammary health and milk hygiene and safety in dairy sheep throughout time.

  4. Neurotrophic Factor Control of Satiety and Body Weight

    Science.gov (United States)

    Xu, Baoji; Xie, Xiangyang

    2016-01-01

    Energy balance, the relationship between energy intake and expenditure, is regulated by a complex interplay of hormones, brain circuits and peripheral tissues. Leptin is an adipocyte-derived cytokine that suppresses appetite and increases energy expenditure. Ironically, obese individuals have high levels of plasma leptin and are resistant to leptin treatment. Neurotrophic factors, particularly ciliary neurotrophic factor (CNTF) and brain-derived neurotrophic factor (BDNF), are also important for the control of body weight. CNTF can overcome leptin resistance to reduce body weight, although CNTF and leptin activate similar signalling cascades. Mutations in the gene for BDNF lead to insatiable appetite and severe obesity. PMID:27052383

  5. Transcription Factor Zbtb20 Controls Regional Specification of Mammalian Archicortex

    DEFF Research Database (Denmark)

    Rosenthal, Eva Helga

    2010-01-01

    Combinatorial expression of sets of transcription factors (TFs) along the mammalian cortex controls its subdivision into functional areas. Unlike neocortex, only few recent data suggest genetic mechanisms controlling the regionalization of the archicortex. TF Emx2 plays a crucial role in patterning...... later on becoming restricted exclusively to postmitotic neurons of hippocampus (Hi) proper, dentate gyrus (DG), and two transitory zones, subiculum (S) and retrosplenial cortex (Rsp). Analysis of Zbtb20-/- mice revealed altered cortical patterning at the border between neocortex and archicortex...

  6. Teleoperator hand controllers: A contextual human factors assessment

    Energy Technology Data Exchange (ETDEWEB)

    Draper, J.V.

    1994-05-01

    This document provides a human factors assessment of controllers for use with remotely controlled manipulators deployed to remove hazardous waste from underground storage tanks. The analysis concentrates on controller technique (i.e., the broad class of hand controller) and not on details of controller ergonomics. Examples of controller techniques include, for example, direct rate control, resolved unilateral position control, and direct bilateral position control. Using an existing concept, the Tank Waste Retrieval Manipulator System, as a reference, two basic types of manipulators may be identified for this application. A long reach, gross-positioning manipulator (LRM) may be used to position a smaller manipulator or an end-effector within a work site. For a Long Reach Manipulator, which will have an enormous motion range and be capable of high end-effector velocity, it will be safest and most efficient to use a resolved rate control system. A smaller, dexterous manipulator may be used to perform handling work within a relatively small work site, (i.e., to complete tasks requiring near-human dexterity). For a Dexterous Manipulator, which will have a smaller motion range than the LRM and be required to perform more difficult tasks, a resolved bilateral position control system will be safest and most efficient. However, during some waste recovery tasks it may be important to support the users by restricting movements to a single plane or axis. This can be done with a resolved bilateral position control system by (1) using the master controller force output to restrict controller inputs or (2) switching the controller to a multiaxis rate control mode and using the force output to provide a spring return to center functionality.

  7. Potential risk factors for diabetic neuropathy: a case control study

    Directory of Open Access Journals (Sweden)

    Nooraei Mahdi

    2005-12-01

    Full Text Available Abstract Background Diabetes mellitus type II afflicts at least 2 million people in Iran. Neuropathy is one of the most common complications of diabetes and lowers the patient's quality of life. Since neuropathy often leads to ulceration and amputation, we have tried to elucidate the factors that can affect its progression. Methods In this case-control study, 110 diabetic patients were selected from the Shariati Hospital diabetes clinic. Michigan Neuropathic Diabetic Scoring (MNDS was used to differentiate cases from controls. The diagnosis of neuropathy was confirmed by nerve conduction studies (nerve conduction velocity and electromyography. The multiple factors compared between the two groups included consumption of angiotensin converting enzyme inhibitors (ACEI, blood pressure, serum lipid level, sex, smoking, method of diabetes control and its quality. Results Statistically significant relationships were found between neuropathy and age, gender, quality of diabetes control and duration of disease (P values in the order: 0.04, 0.04, Conclusion In this study, hyperglycemia was the only modifiable risk factor for diabetic neuropathy. Glycemic control reduces the incidence of neuropathy, slows its progression and improves the diabetic patient's quality of life. More attention must be paid to elderly male diabetic patients with poor diabetes control with regard to regular foot examinations and more practical education.

  8. Clinical risk factors, bacterial aetiology, and outcome of urinary tract infection in children hospitalized with diarrhoea in Bangladesh.

    Science.gov (United States)

    DAS, R; Ahmed, T; Saha, H; Shahrin, L; Afroze, F; Shahid, A S M S B; Shahunja, K M; Bardhan, P K; Chisti, M J

    2017-04-01

    Urinary tract infection (UTI) is common in children aged <5 years with diarrhoea, but little is known about risk factors, aetiology and outcome of such children. We aimed to evaluate these knowledge gaps of UTI in children aged <5 years with diarrhoea. We enrolled all children aged <5 years with diarrhoea admitted to Dhaka Hospital of the International Centre for Diarrhoeal Disease Research, Bangladesh, between May 2011 and April 2013, who had history of fever (⩾38 °C) and obtained a urine sample for culture. Diarrhoea with UTI (confirmed by culture) constituted cases (n = 26) and those without UTI constituted controls (n = 78). Threefold controls were randomly selected. The case-fatality rate was comparable in cases and controls (4% vs. 1%, P = 0·439). Escherichia coli (69%) and Klebsiella (15%) were the most commonly isolated pathogens. Persistent diarrhoea, pneumonia and prior antibiotics use were identified as risk factors for UTI in logistic regression analysis (P < 0·05 for all). Thus, children with diarrhoea presenting with persistent diarrhoea, pneumonia, and prior antibiotic use should be investigated for UTI for their prompt management that may reduce morbidity.

  9. Internalization of bacterial pathogens in tomatoes and their control by selected chemicals.

    Science.gov (United States)

    Ibarra-Sánchez, L S; Alvarado-Casillas, S; Rodríguez-García, M O; Martínez-Gonzáles, N E; Castillo, A

    2004-07-01

    The effect of different washing or sanitizing agents was compared for preventing or reducing surface and internal contamination of tomatoes by Salmonella Typhimurium and Escherichia coli O157:H7. The tomatoes were inoculated by dipping them in a bacterial suspension containing approximately 6.0 log CFU/ml of each pathogen and then rinsing them with tap water, hypochlorite solution (250 mg/liter), or lactic acid solution (2%, wt/vol). All treatments were applied by dipping or spraying, and solutions were applied at 5, 25, 35, and 55 degrees C. With the exception of the lactic acid dip at 5 degrees C, all treatments reduced both pathogens on the surfaces of the tomatoes by at least 2.9 cycles. No significantly different results were obtained (P > 0.05) with the dipping and spraying techniques. For internalized pathogens, the mean counts for tomatoes treated with water alone or with chlorine ranged from 0.8 to 2.1 log CFU/g. In contrast, after lactic acid spray treatment, all core samples of tomatoes tested negative for Salmonella Typhimurium and, except for one sample with a low but detectable count, all samples tested negative for E. coli O157:H7 with a plate count method. When the absence of pathogens was verified by an enrichment method, Salmonella was not recovered from any samples, whereas two of four samples tested positive for E. coli O157:H7 even though the counts were negative. Few cells of internalized pathogens were able to survive in the center of the tomato during storage at room temperature (25 to 28 degrees C). The average superficial pH of tomatoes treated with tap water, chlorine, or lactic acid was 4.9 to 5.2, 4.1 to 4.3, and 2.5, respectively (P tomatoes treated with different sanitizers. The general practice in the tomato industry is to wash the tomatoes in chlorinated water. However, chlorine is rapidly degraded by organic matter usually present in produce. Therefore, lactic acid sprays may be a more effective alternative for decontaminating

  10. Bacterial colonization factors control specificity and stability of the gut microbiota

    OpenAIRE

    Lee, S. Melanie; Donaldson, Gregory P.; Mikulski, Zbigniew; Boyajian, Silva; Ley, Klaus; Mazmanian, Sarkis K.

    2013-01-01

    Mammals harbor a complex gut microbiome, comprised of bacteria that confer immunologic, metabolic and neurologic benefits 1 . Despite advances in sequence-based microbial profiling and myriad studies defining microbiome composition during health and disease, little is known about the molecular processes employed by symbiotic bacteria to stably colonize the gastrointestinal (GI) tract. We sought to define how mammals assemble and maintain the Bacteroides, one of the most numerically prominent ...

  11. Bacterial wall products induce downregulation of vascular endothelial growth factor receptors on endothelial cells via a CD14-dependent mechanism: implications for surgical wound healing.

    LENUS (Irish Health Repository)

    Power, C

    2012-02-03

    INTRODUCTION: Vascular endothelial growth factor (VEGF) is a potent mitogenic cytokine which has been identified as the principal polypeptide growth factor influencing endothelial cell (EC) migration and proliferation. Ordered progression of these two processes is an absolute prerequisite for initiating and maintaining the proliferative phase of wound healing. The response of ECs to circulating VEGF is determined by, and directly proportional to, the functional expression of VEGF receptors (KDR\\/Flt-1) on the EC surface membrane. Systemic sepsis and wound contamination due to bacterial infection are associated with significant retardation of the proliferative phase of wound repair. The effects of the Gram-negative bacterial wall components lipopolysaccharide (LPS) and bacterial lipoprotein (BLP) on VEGF receptor function and expression are unknown and may represent an important biological mechanism predisposing to delayed wound healing in the presence of localized or systemic sepsis. MATERIALS AND METHODS: We designed a series of in vitro experiments investigating this phenomenon and its potential implications for infective wound repair. VEGF receptor density on ECs in the presence of LPS and BLP was assessed using flow cytometry. These parameters were assessed in hypoxic conditions as well as in normoxia. The contribution of CD14 was evaluated using recombinant human (rh) CD14. EC proliferation in response to VEGF was quantified in the presence and absence of LPS and BLP. RESULTS: Flow cytometric analysis revealed that LPS and BLP have profoundly repressive effects on VEGF receptor density in normoxic and, more pertinently, hypoxic conditions. The observed downregulation of constitutive and inducible VEGF receptor expression on ECs was not due to any directly cytotoxic effect of LPS and BLP on ECs, as measured by cell viability and apoptosis assays. We identified a pivotal role for soluble\\/serum CD14, a highly specific bacterial wall product receptor, in

  12. Dominant factors in controlling marine gas pools in South China

    Science.gov (United States)

    Xu, S.; Watney, W.L.

    2007-01-01

    In marine strata from Sinian to Middle Triassic in South China, there develop four sets of regional and six sets of local source rocks, and ten sets of reservoir rocks. The occurrence of four main formation periods in association with five main reconstruction periods, results in a secondary origin for the most marine gas pools in South China. To improve the understanding of marine gas pools in South China with severely deformed geological background, the dominant control factors are discussed in this paper. The fluid sources, including the gas cracked from crude oil, the gas dissolved in water, the gas of inorganic origin, hydrocarbons generated during the second phase, and the mixed pool fluid source, were the most significant control factors of the types and the development stage of pools. The period of the pool formation and the reconstruction controlled the pool evolution and the distribution on a regional scale. Owing to the multiple periods of the pool formation and the reconstruction, the distribution of marine gas pools was complex both in space and in time, and the gas in the pools is heterogeneous. Pool elements, such as preservation conditions, traps and migration paths, and reservoir rocks and facies, also served as important control factors to marine gas pools in South China. Especially, the preservation conditions played a key role in maintaining marine oil and gas accumulations on a regional or local scale. According to several dominant control factors of a pool, the pool-controlling model can be constructed. As an example, the pool-controlling model of Sinian gas pool in Weiyuan gas field in Sichuan basin was summed up. ?? Higher Education Press and Springer-Verlag 2007.

  13. Dominant factors in controlling marine gas pools in South China

    Institute of Scientific and Technical Information of China (English)

    XU Sihuang; W.Lynn Watney

    2007-01-01

    In marine strata from Sinian to Middle Triassic in South China,there develop four sets of regional and six sets of local source rocks,and ten sets of reservoir rocks.The occurrence of four main formation periods in association with five main reconstruction periods,results in a secondary origin for the most marine gas pools in South China.To improve the understanding of marine gas pools in South China with severely deformed geological background,the dominant control factors are discussed in this paper.The fluid sources,including the gas cracked from crude oil,the gas dissolved in water,the gas of inorganic origin,hydrocarbons generated during the second phase,and the mixed pool fluid source,were the most significant control factors of the types and the development stage of pools.The period of the pool formation and the reconstruction controlled the pool evolution and the distribution on a regional scale.Owing to the multiple periods of the pool formation and the reconstruction,the distribution of marine gas pools was complex both in space and in time,and the gas in the pools is heterogeneous.Pool elements,such as preservation conditions,traps and migration paths,and reservoir rocks and facies,also served as important control factors to marine gas pools in South China.Especially,the preservation conditions played a key role in maintaining marine oil and gas accumulations on a regional or local scale.According to several dominant control factors of a pool,the pool-controlling model can be constructed.As an example,the pool-controlling model of Sinian gas pool in Weiyuan gas field in Sichuan basin was summed up.

  14. Physiology and Endocrinology Symposium. Factors controlling puberty in beef heifers

    Science.gov (United States)

    The Physiology and Endocrinology Symposium on “Factors controlling puberty in beef heifers” was held at the joint annual meeting of the American Dairy Science Association and the American Society of Animal Science in New Orleans, Louisiana, USA, July 10 to 14, 2011. The objective of the symposium w...

  15. Responses of Lens esculenta Moench to controlled environmental factors

    NARCIS (Netherlands)

    Saint-Clair, P.M.

    1972-01-01

    Many experiments were undertaken to study the responses of the lentil cultivars 'Large blonde' and 'Anicia' to controlled environmental factors. They covered different aspects of the physiology and the ecology of the crop.The orientation experiments (2) involved germination and depth of sowing. The

  16. Simple Expressions for Safety Factors in Inventory Control

    NARCIS (Netherlands)

    Strijbosch, L.W.G.; Moors, J.J.A.

    1999-01-01

    The literature on inventory control discusses many methods to establish the level of decision parameters -like reorder levels or safety factors-, necessary to attain a prescribed service level. In general, however, these methods are not easy applicable: they often use time-consuming iterations, requ

  17. Behavioural factors related to metabolic control in patients with phenylketonuria

    NARCIS (Netherlands)

    Crone, MR; van Spronsen, FJ; Oudshoorn, K; Bekhof, J; van Rijn, G; Verkerk, PH

    2005-01-01

    Background. The objective of this study was to determine the importance of parental factors possibly related to dietary control in early and continuously treated patients with phenylketonuria (PKU). Methods. A questionnaire was disseminated among parents of 238 patients with PKU born after the natio

  18. The use of bacterial larvicides in mosquito and black fly control programmes in Brazil

    Directory of Open Access Journals (Sweden)

    Regis Lêda

    2000-01-01

    Full Text Available Bacillus spp. based larvides are increasingly replacing, with numerous advantages, chemical insecticides in programmes for controlling black fly and mosquito populations. Brazil was among the pioneers in adopting Bacillus thuringiensis israelensis (B.t.i to control black flies. However, the major current mosquito control programme in Brazil, the Programme for Eradication of Aedes aegypti launched in 1997, only recently decided to replace temephos by B.t.i based larvicides, in the State of Rio de Janeiro. In the last decade, works developed by research groups in Brazilian institutions have generated a significant contribution to this subject through the isolation of B. sphaericus new strains, the development of new products and the implementation of field trials of Bacillus efficacy against mosquito species under different environmental conditions.

  19. Designing Simulation Experiments with Controllable and Uncontrollable Factors

    DEFF Research Database (Denmark)

    Dehlendorff, Christian; Kulahci, Murat; Andersen, Klaus Kaae

    In this study we propose a new method for designing computer experiments inspired by the split plot designs used in physical experimentation. The basic layout is that each set of controllable factor settings corresponds to a whole plot for which a number of subplots, each corresponding to one...... combination of settings of the uncontrollable factors, is employed. The caveat is a desire that the subplots within each whole plot cover the design space uniformly. A further desire is that in the combined design, where all experimental runs are considered at once, the uniformity of the design space coverage...... should be guaranteed. Our proposed method allows for a large number of uncontrollable and controllable settings to be run in a limited number of runs while uniformly covering the design space for the uncontrollable factors....

  20. Genetic control of growth traits and inheritance of resistance to bacterial leaf scorch in American Sycamore

    Science.gov (United States)

    J.P. Adams; R. J. Rousseau; T. D. Leininger

    2012-01-01

    Open-pollinated progeny tests of American sycamore (Platanus occidentalis L.), which included 55 open-pollinated families selected from several prior Westvaco progeny tests and seed orchards and six control-pollinated families were established in 2002 and 2003. The half-sibling families were planted at two sites in western Kentucky and southeastern...

  1. Control of bacterial chromosome replication by non-coding regions outside the origin

    DEFF Research Database (Denmark)

    Frimodt-Møller, Jakob; Charbon, Godefroid; Løbner-Olesen, Anders

    2017-01-01

    Chromosome replication in Eubacteria is initiated by initiator protein(s) binding to specific sites within the replication origin, oriC. Recently, initiator protein binding to chromosomal regions outside the origin has attracted renewed attention; as such binding sites contribute to control the f...

  2. Antibiotics production by bacterial agents and its role in biological control

    NARCIS (Netherlands)

    Wang, G.; Raaijmakers, J.M.

    2004-01-01

    Using bacteria to control plant diseases is one of the main strategies in plant protection, and its mechanism is commonly thought to be the production of antibiotics by bacteria. The produced antibiotics not only have structural diversity, but also have broad-spectrum activity against many pathogens

  3. Whole-Genome Sequencing of Invasion-Resistant Cells Identifies Laminin α2 as a Host Factor for Bacterial Invasion

    DEFF Research Database (Denmark)

    van Wijk, Xander M.; Döhrmann, Simon; Hallstrom, Bjorn

    2017-01-01

    To understand the role of glycosaminoglycans in bacterial cellular invasion, xylosyltransferase-deficient mutants of Chinese hamster ovary (CHO) cells were created using clustered regularly interspaced short palindromic repeat (CRISPR) and CRISPR-associated gene 9 (CRISPR-cas9) gene targeting. When...... cells. Whole-genome sequencing and transcriptome sequencing (RNA-Seq) uncovered a deletion in the gene encoding the laminin subunit α2 (Lama2) that eliminated much of domain L4a. Silencing of the long Lama2 isoform in wild-type cells strongly reduced bacterial invasion, whereas transfection with human...

  4. Effects of gastric irrigation on bacterial counts before endoscopic submucosal dissection: a randomized case control prospective study.

    Directory of Open Access Journals (Sweden)

    Hirohito Mori

    Full Text Available OBJECTIVE: The antiseptic effect of gastric irrigation before endoscopic submucosal dissection (ESD has not yet been reported. The aim of the randomized prospective study is to evaluate the antiseptic effects of gastric irrigation of saline solution before ESD by evaluating bacterial count. METHODS: This prospective randomized controlled trial included 50 patients diagnosed with early gastric cancer who were randomly divided into 2 groups (25 patients in each group by using the opaque envelope method: the clean group (irrigation with 2 L saline solution before ESD and the regular group (no irrigation. The gastric juice was collected and cultured before ESD. The entire stomach was irrigated using a water jet attached to an endoscope. After ESD with resection and removal of the tumor specimen, a postoperative culture of the gastric juice was obtained using the same method as the preoperative culture. RESULTS: The mean log bacterial count of the post-gastric irrigation gastric juice was 5.08±0.75 in the regular group and 1.86±0.86 in the clean group. The difference in the bacterial counts was significant between the groups (P = 0.0004. The difference in the white blood cells (WBC count on POD 1 was significant (P = 0.044. WBC count on POD 2 did not significantly differ between the groups (P = 0.3. The difference in the body temperature (BT on POD 1 was significant (P = 0.017, On POD 2 the BT was not significant between the groups (P = 0.5. On POD 1, 88% of the patients in the regular group and 16% of the patients in the clean group had mild to moderate spontaneous pain (P = 0.0026. On POD 2 the proportion with mild to moderate spontaneous pain was 36% and 24% in the regular group and the clean group, respectively (P = 0.1. CONCLUSION: Pre-ESD gastric irrigation with saline solution is effective and feasible for suppressing infection during the ESD procedure with favorable clinical outcomes. TRIAL REGISTRATION

  5. Identification and characterization of a novel bacterial virulence factor that shares homology with mammalian Toll/interleukin-1 receptor family proteins.

    Science.gov (United States)

    Newman, Ruchi M; Salunkhe, Prabhakar; Godzik, Adam; Reed, John C

    2006-01-01

    Many important bacterial virulence factors act as mimics of mammalian proteins to subvert normal host cell processes. To identify bacterial protein mimics of components of the innate immune signaling pathway, we searched the bacterial genome database for proteins with homology to the Toll/interleukin-1 receptor (TIR) domain of the mammalian Toll-like receptors (TLRs) and their adaptor proteins. A previously uncharacterized gene, which we have named tlpA (for TIR-like protein A), was identified in the Salmonella enterica serovar Enteritidis genome that is predicted to encode a protein resembling mammalian TIR domains, We show that overexpression of TlpA in mammalian cells suppresses the ability of mammalian TIR-containing proteins TLR4, IL-1 receptor, and MyD88 to induce the transactivation and DNA-binding activities of NF-kappaB, a downstream target of the TIR signaling pathway. In addition, TlpA mimics the previously characterized Salmonella virulence factor SipB in its ability to induce activation of caspase-1 in a mammalian cell transfection model. Disruption of the chromosomal tlpA gene rendered a virulent serovar Enteritidis strain defective in intracellular survival and IL-1beta secretion in a cell culture infection model using human THP1 macrophages. Bacteria with disrupted tlpA also displayed reduced lethality in mice, further confirming an important role for this factor in pathogenesis. Taken together, our findings demonstrate that the bacterial TIR-like protein TlpA is a novel prokaryotic modulator of NF-kappaB activity and IL-1beta secretion that contributes to serovar Enteritidis virulence.

  6. Risk factors of Cancer Prostate A case control study.

    Science.gov (United States)

    Kamel, Nahed M; Tayel, Eiman S; El Abbady, Ahmed A; Khashab, Sahar S

    2006-01-01

    The purpose of this study is to reveal the different risk factors related to this cancer particularly that there is no agreement about which factors affect the risk. A fishing expedition hospital based case control study was carried out. Cases and controls were identified from the Urology Department of Alexandria Main University Hospital, 2004. All cases diagnosed as having the tumor were included in the case series. For each case the second subject proved to have a negative pathological examination was included in the control group (50).Data collection was carried out blindly using a structured interview schedule. Analysis was applied using Chi-square test, Fisher exact and Student's t-test. Odds Ratios and 95% Confidence Intervals were calculated. Results indicated that regular consumption of sausages was greater among cases than controls (X(2)= 10.19, p= 0.001 and an odds ratio of 5.92 (CI: 1.69-25.99). Also more cases claimed consuming regularly butter and natural ghee than controls (X(2)= 5.47, p= 0.019). The estimate risk was as high as 2.79 (Cl: 1.07-7.33). However regular consumption of vegetables was more encountered among controls than cases (X(2) = 5.005, p= 0.025 where the odds ratio was 0.19 (Cl: 0.02-1.01). Moreover the multiple regression analysis confirmed the results obtained from univariate analysis. The consistency of results of current work as regards sausages and butter with several other research works can support the identification of these specific possible risk factors. Also other research workers pointed out to the protective effect of vegetables. However further research is needed to address other risk factors.

  7. Simplifying the audit of risk factor recording and control

    DEFF Research Database (Denmark)

    Zhao, Min; Cooney, Marie Therese; Klipstein-Grobusch, Kerstin

    2016-01-01

    BACKGROUND: To simplify the assessment of the recording and control of coronary heart disease risk factors in different countries and regions. DESIGN: The SUrvey of Risk Factors (SURF) is an international clinical audit. METHODS: Data on consecutive patients with established coronary heart disease...... from countries in Europe, Asia and the Middle East were collected on a one-page collection sheet or electronically during routine clinic visits. Information on demographics, diagnostic category, risk factors, physical and laboratory measurements, and medications were included and key variables...... summarized in a Cardiovascular Health Index Score. RESULTS: Coronary heart disease patients (N = 10,186; 29% women) were enrolled from 79 centres in 11 countries. Recording of risk factors varied considerably: smoking was recorded in over 98% of subjects, while about 20% lacked data on laboratory...

  8. Risk factors for anal fistula: a case-control study.

    Science.gov (United States)

    Wang, D; Yang, G; Qiu, J; Song, Y; Wang, L; Gao, J; Wang, C

    2014-07-01

    The aim of our study was to identify potential risk factors for anal fistula in order to improve prevention and treatment of anal fistula. A retrospective case-control study for anal fistula was conducted at our unit. Logistic regression analyses were carried out to identify associated risk factors for anal fistula. The final model obtained by the stepwise forward logistic regression analysis method identified the following items as independent risk factors: body mass index of >25.0 kg/m(2), high daily salt intake, history of diabetes, hyperlipidemia, dermatosis, anorectal surgery, history of smoking and alcohol intake, sedentary lifestyle, excessive intake of spicy/greasy food, very infrequent participation in sports and prolonged sitting on the toilet for defecation. Our results indicate that lifestyle factors and certain medical conditions increase an individual's risk of developing anal fistula.

  9. Bacterial endogenous endophthalmitis in Vietnam: a randomized controlled trial comparing vitrectomy with silicone oil versus vitrectomy alone

    Directory of Open Access Journals (Sweden)

    Do T

    2014-08-01

    Full Text Available Tan Do,1 Do N Hon,1 Tin Aung,2 Nguyen DTN Hien,1 Claude L Cowan Jr3 1Vietnam National Institute of Ophthalmology, Hanoi, Vietnam; 2Singapore National Eye Center, Singapore; 3Georgetown University Medical Center, Washington, DC, USA Background/aims: To compare treatment outcomes with and without silicone oil tamponade in patients undergoing pars plana vitrectomy (PPV for severe endogenous bacterial endophthalmitis (BEE. Methods: One hundred and eight consecutive patients with severe BEE (defined by the absence of pupil red reflex at presentation and/or dense vitreous opacity on ultrasound and no improvement after 24–36 hours of medical treatment were randomly assigned to two treatment groups: Group 1, standard PPV with intravitreal antibiotics; and Group 2, PPV with intravitreal antibiotics and silicone tamponade. Overall success was defined as: a visual acuity ≥ count fingers at 1 meter, with an attached retina, and no intraocular oil. Results: Fifty three patients were randomized to Group 1 and 55 patients to Group 2. The mean age of study subjects was 32 years and baseline clinical characteristics were similar in both groups. At the final follow-up visit at 9 months, the overall success rate of Group 2 (67.3% was significantly better than Group 1 (43.4%; P=0.01. There were also fewer devastating complications (such as inoperable retinal detachment, phthisis bulbi in Group 2 compared with Group 1 (21.8% versus 43.4%; P=0.01. Conclusion: The outcome at 9 months of patients with BEE treated by vitrectomy with silicone oil was better than those treated by vitrectomy alone. Keywords: bacterial endogenous endophthalmitis, vitrectomy, silicone oil endotamponade, randomized controlled trial

  10. Controle químico da mancha-bacteriana do tomate para processamento industrial em campo Field chemical control of bacterial spot on tomato for industrial processing

    Directory of Open Access Journals (Sweden)

    Abadia dos R Nascimento

    2013-03-01

    cloretos de benzalcônio. ASM e famoxadona + mancozebe foram os que promoveram uma relação benefício/custo superior a 1.In order to evaluate chemical control of bacterial spot on tomato for industrial processing, two field trials were carried out at the Unilever Bestfoods experimental station, in Goiânia, Goias state, Brazil. The first trial was in a randomized complete block design, with 15 treatments and three replications, using the hybrid Heinz 9992 inoculated with Xanthomonas perforans. The second trial was in a split-plot randomized complete block design with chemical foliar applications (10 treatments and hybrids (Hypeel 108 and U2006 as factors. Plants were inoculated with X. perforans and X. gardneri. In both trials the chemicals, in different number of applications and combinations, were: acibenzolar-S-methyl (ASM; famoxadone + mancozeb; metiram + pyraclostrobin; phosphite PK; benzalkonium chlorides; cuprous oxide, and copper hydroxide (SC, WP and WG. For both trials, disease severity on leaves, number of fruits with symptoms and yield were evaluated. In the second one, sunscald was also evaluated. For the first trial, significant severity differences (p>0.05 among treatments were observed only in the first two evaluations, but none of them differed from the water check control. In the second trial, significant differences were detected only in foliar severity in first evaluation for hybrids. For number of fruits with symptoms and sunscald, besides hybrids, interaction among factors was also significant. 'U2006' was more resistant than 'Hypeel 108', which also had highest sunscald values, but concerning fruits with symptoms, the opposite was observed. The two factors were significant for yield data, 'U2006' yielded better than 'Hypeel 108'. Despite none of the treatments have differed in yield from the water control, famoxadone + mancozeb, which resulted in the highest yield, differed from copper hydroxide, ASM - famoxadone + mancozeb, and benzalkonium

  11. Transfer of toxin genes to alternate bacterial hosts for mosquito control

    Directory of Open Access Journals (Sweden)

    Sergio Orduz

    1995-02-01

    Full Text Available Mosquitoes are vector of serious human and animal diseases, such as malaria, dengue, yellow fever, among others. The use of biological control agents has provide an environmentally safe and highly specific alternative to the use of chemical insecticides in the control of vector borne diseases. Bacillus thuringiensis and B. sphaericus produce toxic proteins to mosquito larvae. Great progress has been made on the biochemical and molecular characterization of such proteins and the genes encoding them. Nevertheless, the low residuality of these biological insecticides is one of the major drawbacks. This article present some interesting aspects of the mosquito larvae feeding habits and review the attempts that have been made to genetically engineer microorganisms that while are used by mosquito larvae as a food source should express the Bacillus toxin genes in order to improve the residuality and stability in the mosquito breeding ponds.

  12. Remote screening and direct control of the bacterial infection of gardens

    Science.gov (United States)

    Starodub, Nickolaj F.; Shavanova, Kateryna E.; Son'ko, Roman V.

    2014-10-01

    In last time gardens are often at the dangerous of viruses and bacteria infections. To preserve not only the coming harvest, but, in generally, to provide stability and growing horticultures the development of new generation of the analytical techniques for remote express screening vegetative state arrays and direct control of the appropriate infection if appearance of its maybe expected on the basis of previous surveys are very actually and important. For continuous monitoring we propose the application of the complex of the optical analytical devices as "Floratest" and "Plasmatest" (both produced in Ukraine) which is able to control step by step general situation with vegetable state and verify concrete situation with infection. General screening is accomplished on the control of the intensity of chlorophyll induction (IChF), namely, registration of so called Kautsky curve which testifies about physiological mechanisms of energy generation, accumulation and effective ways of its realization in cells. The measuring may be done by direct way on the number of individual vegetables and remote screening of massive with transferring registered signal direct in the laboratory. Next step of control connected with the application of the surface plasmon resonance (SPR) based immune biosensor which is able to determine concrete bacteria (for example, Erwinia amilovora) with the limit detection about 0.2 μg/ml, the overall time of the analysis within 30 min (5 min of the duration of one measurement). The traditional ELISA-method showed the sensitivity to this pathogen about 0.5 μg/ml, overall time of the analysis several hours and obligatory using additional expensive reagents.

  13. Predicting epistasis: an experimental test of metabolic control theory with bacterial transcription and translation.

    Science.gov (United States)

    MacLean, R C

    2010-03-01

    Epistatic interactions between mutations are thought to play a crucial role in a number of evolutionary processes, including adaptation and sex. Evidence for epistasis is abundant, but tests of general theoretical models that can predict epistasis are lacking. In this study, I test the ability of metabolic control theory to predict epistasis using a novel experimental approach that combines phenotypic and genetic perturbations of enzymes involved in gene expression and protein synthesis in the bacterium Pseudomonas aeruginosa. These experiments provide experimental support for two key predictions of metabolic control theory: (i) epistasis between genes involved in the same pathway is antagonistic; (ii) epistasis becomes increasingly antagonistic as mutational severity increases. Metabolic control theory is a general theory that applies to any set of genes that are involved in the same linear processing chain, not just metabolic pathways, and I argue that this theory is likely to have important implications for predicting epistasis between functionally coupled genes, such as those involved in antibiotic resistance. Finally, this study highlights the fact that phenotypic manipulations of gene activity provide a powerful method for studying epistasis that complements existing genetic methods.

  14. Risk factors for infection with carbapenem-resistant Klebsiella pneumoniae: a case-case-control study

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    Viviana Gómez Rueda

    2014-07-01

    Full Text Available Objetive: To evaluate the association between quinolone exposure and the emergence of carbapenem-resistant Klebsiella pneumoniae (CRKP and to estimate CRKP-specific mortality.Methods: Case-case-control study implemented in a tertiary care institution. Three groups of patients were analyzed: 61 consecutive cases of infection with CRKP (Group I; 61 randomly chosen cases of patients infected with carbapenem-sensitive Klebsiella pneumoniae (CSKP; Group II; and 122 randomly chosen controls without CRKP or CSKP infection. Matching was based on the length of stay in intensive care unit and the date of bacterial isolation. An active search was performed for patients with CRKP and CSKP infection, and prospective cases were included in the study. We compared the results for Groups I and II against those for the controls by using two conditional logistic regression analyses that included infection as the dependent variable and controlled for time at risk and co-morbidities.Results: Exposure to quinolones was not associated with CRKP infection: no association was found in the analysis of CRKP with the controls (OR= 1.7; 95% CI: 0.2-6.5 or in the analysis of CSKP against the controls (OR= 0.6; 95% CI: 0.2-1.6. Use of carbapenems (OR = 3.3; 95% CI: 1.2-9.3 and colonization with CRKP (OR = 3.3; 95% IC: 1.2-9.3 were specific risk factors for infection with CRKP. Mortality associated with CRKP was 61.3%.Conclusion: No association was found between exposure to quinolones and infection with CRKP; however, colonization by CRKP and use of carbapenems are risk factors for infection with CRKP.

  15. Factores de necesidad asociados al uso adecuado del control prenatal

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    Clarybel Miranda Mellado

    2016-07-01

    Full Text Available Introducción: Por las implicaciones sociales de la mortalidad y morbilidad materna es importante determinar los factores de necesidad que influyen en el uso adecuado del control prenatal en gestantes de Sincelejo. Materiales y Métodos: Estudio analítico de corte transversal, que incluyó 730 gestantes, seleccionadas mediante muestreo aleatorio por conglomerados, de las comunas de la ciudad. La información fue recolectada por medio de una encuesta sociodemográfica, una ficha de uso de control prenatal y un Cuestionario para evaluar los factores de necesidad  propuestos por el Modelo de Promoción de la Salud de Nola Pender. Las gestantes fueron contactadas en sus domicilios y diligenciaron los instrumentos. Los datos fueron analizados aplicando estadística descriptiva e inferencial para determinar las asociaciones entre variables. Resultados: El 97,7% (713 de las gestantes asistía al control prenatal, con una mediana de 4 controles prenatales. Un 2,3% (17 no lo habían iniciado al momento de la encuesta y 24,4% (178 hizo uso inadecuado. El 80,7% (589 de las gestantes califican su estado de salud como bueno o muy bueno, 94,8% (692 percibieron beneficios del control prenatal. Se encontró asociación significativa entre la percepción de beneficios y el uso adecuado de control prenatal [OR=5,5 (IC 95%: 2,8 - 10,8]. Discusión y Conclusiones: La percepción que las mujeres tienen sobre los buenos resultados que reporta la asistencia al control prenatal, es el principal factor que puede explicar la adherencia al control y el cumplimiento regular de las consultas. Cómo citar este artículo: Miranda C, Castillo IY. Factores de necesidad asociados al uso adecuado del control prenatal. Rev Cuid. 2016; 7(2: 1345-51. http://dx.doi.org/10.15649/cuidarte.v7i2.340

  16. Comparison of result judgment algorithm of test for interfering factors in the bacterial endotoxins test among Chinese, Japanese,European, American, and Indian pharmacopeias

    Institute of Scientific and Technical Information of China (English)

    Pei Yusheng; Cai Tong; Gao Hua; Tan Dejiang; Zhang Yuchen; Zhang Guolai

    2014-01-01

    Background The bacterial endotoxins test (BET) is a method used to detect or quantify endotoxins (lipo-polysaccharide,LPS) and is widely used in the quality control of parenteral medicines/vaccines and clinical dialysis fluid.It is also used in the diagnosis of endotoxemia and in detection of environment air quality control.Although BET has been adopted by most pharmacopoeias,result judgment algorithms (RJAs) of the test for interfering factors in the BET still differ between certain pharmacopoeias.We have evaluated RJAs of the test for interfering factors for the revision of BET described in the Chinese Pharmacopoeia 2010 (CHP2010).Methods Original data from 1 748 samples were judged by RJAs of the Chinese Pharmacopoeia 2010,the Japanese Pharmacopoeia 2011 (JP2011),the European Pharmacopoeia 7.0 (EP7.0),the United States Pharmacopoeia 36 (USP36),and the Indian Pharmacopoeia 2010 (IP2010),respectively.A SAS software package was used in the statistical analysis.Results The results using CHP2010 and USP36,JP2011,EP7.0,and IP2010 had no significant difference (P=-0.7740).The results using CHP2010 of 1 748 samples showed that 132 samples (7.6%) required an additional step; nevertheless there was no such requirement when using the other pharmacopeias.The kappa value of two RJAs (CHP2010 and EP7.0) was 0.6900 (0.6297-0.7504) indicating that the CHP2010 and other pharmacopoeias have good consistency.Conclusions The results using CHP2010 and USP36,JP2011,EP7.0,and IP2010 have different characteristics.CHP2010 method shows a good performance in Specificity,mistake diagnostic rate,agreement rate,predictive value for suspicious rate,and predictive value for passed rate.The CHP2010 method only had disadvantages in sensitivity compared with other pharmacopeias.We suggest that the Chinese pharmacopoeia interference test be revised in accordance with the USP36,JP2011,EP7.0,and IP2010 judgment model.

  17. Whole-Genome Sequencing of Invasion-Resistant Cells Identifies Laminin α2 as a Host Factor for Bacterial Invasion

    Science.gov (United States)

    van Wijk, Xander M.; Döhrmann, Simon; Hallström, Björn M.; Li, Shangzhong; Voldborg, Bjørn G.; Meng, Brandon X.; McKee, Karen K.; van Kuppevelt, Toin H.; Yurchenco, Peter D.; Palsson, Bernhard O.; Lewis, Nathan E.; Nizet, Victor

    2017-01-01

    ABSTRACT To understand the role of glycosaminoglycans in bacterial cellular invasion, xylosyltransferase-deficient mutants of Chinese hamster ovary (CHO) cells were created using clustered regularly interspaced short palindromic repeat (CRISPR) and CRISPR-associated gene 9 (CRISPR-cas9) gene targeting. When these mutants were compared to the pgsA745 cell line, a CHO xylosyltransferase mutant generated previously using chemical mutagenesis, an unexpected result was obtained. Bacterial invasion of pgsA745 cells by group B Streptococcus (GBS), group A Streptococcus, and Staphylococcus aureus was markedly reduced compared to the invasion of wild-type cells, but newly generated CRISPR-cas9 mutants were only resistant to GBS. Invasion of pgsA745 cells was not restored by transfection with xylosyltransferase, suggesting that an additional mutation conferring panresistance to multiple bacteria was present in pgsA745 cells. Whole-genome sequencing and transcriptome sequencing (RNA-Seq) uncovered a deletion in the gene encoding the laminin subunit α2 (Lama2) that eliminated much of domain L4a. Silencing of the long Lama2 isoform in wild-type cells strongly reduced bacterial invasion, whereas transfection with human LAMA2 cDNA significantly enhanced invasion in pgsA745 cells. The addition of exogenous laminin-α2β1γ1/laminin-α2β2γ1 strongly increased bacterial invasion in CHO cells, as well as in human alveolar basal epithelial and human brain microvascular endothelial cells. Thus, the L4a domain in laminin α2 is important for cellular invasion by a number of bacterial pathogens. PMID:28074024

  18. Neuro-intensive treatment targeting intracranial hypertension improves outcome in severe bacterial meningitis: an intervention-control study.

    Directory of Open Access Journals (Sweden)

    Martin Glimåker

    Full Text Available OBJECTIVE: To evaluate the efficacy of early intracranial pressure (ICP-targeted treatment, compared to standard intensive care, in adults with community acquired acute bacterial meningitis (ABM and severely impaired consciousness. DESIGN: A prospectively designed intervention-control comparison study of adult cases from September 2004 to January 2012. PATIENTS: Included patients were confirmed ABM-cases, aged 16-75 years, with severely impaired mental status on admission. Fifty-two patients, given ICP-targeted treatment at the neuro-intensive care unit, and 53 control cases, treated with conventional intensive care, were included. All the patients received intensive care with mechanical ventilation, sedation, antibiotics and corticosteroids according to current guidelines. Additional ICP-treatment in the intervention group included cerebrospinal fluid drainage using external ventricular catheters (n = 48, osmotherapy (n = 21, hyperventilation (n = 13, external cooling (n = 9, gram-doses of methylprednisolone (n = 3 and deep barbiturate sedation (n = 2 aiming at ICP 50 mmHg. MEASUREMENTS: The primary endpoint was mortality at two months and secondary endpoint was Glasgow outcome score and hearing ability at follow-up at 2-6 months. OUTCOMES: The mortality was significantly lower in the intervention group compared to controls, 5/52 (10% versus 16/53 (30%; relative risk reduction 68%; p<0.05. Furthermore, only 17 patients (32% in the control group fully recovered compared to 28 (54% in the intervention group (relative risk reduction 40%; p<0.05. CONCLUSIONS: Early neuro-intensive care using ICP-targeted therapy, mainly cerebrospinal fluid drainage, reduces mortality and improves the overall outcome in adult patients with ABM and severely impaired mental status on admission.

  19. Discussion on Occurrence and Prevention and Control Technology of Rice Bacterial Foot-rot Disease%水稻细菌性基腐病的发生与防控技术探讨

    Institute of Scientific and Technical Information of China (English)

    危崇德

    2013-01-01

    Rice bacterial foot-rot disease is one of the most important diseases in rice, in recent years, has happened in southern rice areas and caused a severe yield loss of rice crop. In this paper, influencing factors and disease symptom of rice bacterial foot-rot disease were introduced, and puts forward the corresponding prevention and control technical measures, provide a reference for the effective control of rice bacterial foot- rot disease.%水稻细菌性基腐病是水稻上重要的细菌病害之一,近几年在南方稻区陆续发生,已给水稻生产带来较为严重威胁。介绍了水稻细菌性基腐病的为害症状、影响因素,并提出了相应的防控技术措施,为有效控制水稻细菌性基腐病提供参考。

  20. The prophylactic effect of ceftazidime on early bacterial infection after autologous peripheral blood stem cell transplantation: a prospective randomized controlled trial

    Institute of Scientific and Technical Information of China (English)

    段明辉

    2013-01-01

    Objective To evaluate the efficacy and safety of prophylactic ceftazidime on early bacterial infection in APBSCT recipients during neutropenia.Methods APBSCT recipients were prospectively randomly assigned to intravenous ceftazidime treatment group and control group (no prophylaxis of antibiotics) .The treatment started from the first day until resolution of neutropenia or the

  1. Regulated bioluminescence as a tool for bioremediation process monitoring and control of bacterial cultures

    Science.gov (United States)

    Burlage, Robert S.; Heitzer, Armin; Digrazia, Philip M.

    1991-01-01

    An effective on-line monitoring technique for toxic waste bioremediation using bioluminescent microorganisms has shown great potential for the description and optimization of biological processes. The lux genes of the bacterium Vibrio fischeri are used by this species to produce visible light. The lux genes can be genetically fused to the control region of a catabolic gene, with the result that bioluminescence is produced whenever the catabolic gene is induced. Thus the detection of light from a sample indicates that genetic expression from a specific gene is occurring. This technique was used to monitor biodegradation of specific contaminants from waste sites. For these studies, fusions between the lux genes and the operons for naphthalene and toluene/xylene degradation were constructed. Strains carrying one of these fusions respond sensitively and specifically to target substrates. Bioluminescence from these cultures can be rapidly measured in a nondestructive and noninvasive manner. The potential for this technique in this and other biological systems is discussed.

  2. 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

  3. Terrestrial runoff controls the bacterial community composition of biofilms along a water quality gradient in the Great Barrier Reef.

    Science.gov (United States)

    Witt, Verena; Wild, Christian; Uthicke, Sven

    2012-11-01

    16S rRNA gene molecular analysis elucidated the spatiotemporal distribution of bacterial biofilm communities along a water quality gradient. Multivariate statistics indicated that terrestrial runoff, in particular dissolved organic carbon and chlorophyll a concentrations, induced shifts of specific bacterial communities between locations and seasons, suggesting microbial biofilms could be suitable bioindicators for water quality.

  4. Rizobactérias no controle da mancha angular do algodoeiro Rhizobacteria to control cotton bacterial blight

    Directory of Open Access Journals (Sweden)

    Alessandra Keiko Nakasone Ishida

    2008-02-01

    Full Text Available Avaliou-se o potencial de rizobactérias na indução de resistência do algodoeiro à Xanthomonas axonopodis pv. malvacearum. Após o isolamento das rizobactérias, foram selecionados os isolados capazes de reduzir os sintomas da mancha angular bacteriana em casa de vegetação, os quais foram aplicados espacialmente separados do patógeno desafiador. Os melhores isolados foram testados quanto à capacidade de reduzir os sintomas da ramulose e da murcha de Verticillium e de inibir diretamente os patógenos in vitro. Do total de 123 isolados de rizobactérias foram selecionados cinco, L2-1 (Bacillus cereus, MT5-6 (Bacillus cereus, L2-2 (Achromobacter xylosoxidans, MT5-5 (Bacillus cereus e MT5-11 (Brevibacterium sp., os quais apresentaram controle da mancha angular acima de 40%, em relação à testemunha. Nenhum isolado reduziu a severidade da ramulose e da murcha de Verticillium em relação à testemunha, nem apresentou efeito inibitório direto in vitro a X. axonopodis pv. malvacearum e Colletotrichum gossypii var. cephalosporioides. Para V. dahliae, apenas o isolado L2-1 apresentou efeito inibitório.The potential of rhizobacteria was evaluated for resistance induction against Xanthomonas axonopodis pv. malvacearum. After isolation, the rhizobacteria were screened for the reduction of angular leaf spot severity under greenhouse conditions. They were spatially separated from the challenging pathogen. The best isolates were tested for the capacity to reduce ramulose and Verticillium wilt severity and directly inhibit pathogens in vitro. From a total of 123 rhizobacterial isolates, five were selected, L2-1 (Bacillus cereus, MT5-6 (Bacillus cereus, L2-2 (Achromobacter xylosoxidans, MT5-5 (Bacillus cereus and MT5-11 (Brevibacterium sp., which showed angular leaf spot control above 40% as compared to the control. The tested isolates neither reduced the severity of ramulose and verticillium wilt compared to the control nor showed in vitro direct

  5. Risk factors for episiotomy: a case-control study

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    Giordana Campos Braga

    2014-10-01

    Full Text Available Objective: obtaining information on the factors associated with episiotomy will be useful in sensitizing professionals to the need to minimize its incidence. Therefore, the objective of this study was to evaluate risk factors for episiotomy in pregnant women who had undergone vaginal delivery at a university maternity hospital in northeastern Brazil. Methods: a case-control study was conducted with pregnant women submitted to episiotomy (cases and pregnant women not submitted to episiotomy (controls between March 2009 and July 2010 at the Professor Fernando Figueira Integral Medicine Institute (IMIP in Recife, Brazil, in a ratio of 1 case to 2 controls. The study variables consisted of: whether episiotomy was performed, demographic, obstetric and fetal characteristics (primiparity, analgesia, instrumental delivery, fetal distress, etc., external factors (day and time of delivery, professional attending delivery and factors directly related to delivery. Odds ratios (OR and 95% confidence intervals (95%CI were calculated. Multivariate analysis was performed to determine the adjusted risk of episiotomy. Results: a total of 522 women (173 cases and 349 controls were included. It was found that deliveries with episiotomy were more likely to have been attended by staff physicians (OR = 1.88; 95%CI: 1.01 - 3.48, to have required forceps (OR = 12.31; 95%CI: 4.9 - 30.1 and to have occurred in primiparas (OR = 4.24; 95%CI: 2.61 - 6.89. The likelihood of a nurse having attended the delivery with episiotomy was significantly lower (OR = 0.29; 95%CI: 0.16 - 0.55. Conclusion: episiotomy was found to be strongly associated with deliveries attended by staff physicians, with primiparity, and with instrumental delivery, and was less common in deliveries attended by nurses.

  6. 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 ...

  7. PROTEIN QUALITY CONTROL IN BACTERIAL CELLS: INTEGRATED NETWORKS OF CHAPERONES AND ATP-DEPENDENT PROTEASES.

    Energy Technology Data Exchange (ETDEWEB)

    FLANAGAN,J.M.BEWLEY,M.C.

    2002-10-01

    aggregation and/or mislfolding. Thus it is not surprising that, in cells, the protein folding process is error prone and organisms have evolved ''editing'' or quality control (QC) systems to assist in the folding, maintenance and, when necessary, selective removal of damaged proteins. In fact, there is growing evidence that failure of these QC-systems contributes to a number of disease states (5-8). This chapter describes our current understanding of the nature and mechanisms of the protein quality control systems in the cytosol of bacteria. Parallel systems are exploited in the cytosol and mitochondria of eukaryotes to prevent the accumulation of misfolded proteins.

  8. PROTEIN QUALITY CONTROL IN BACTERIAL CELLS: INTEGRATED NETWORKS OF CHAPERONES AND ATP-DEPENDENT PROTEASES.

    Energy Technology Data Exchange (ETDEWEB)

    FLANAGAN,J.M.; BEWLEY,M.C.

    2001-12-03

    /or misfolding. Thus it is not surprising that, in cells, the protein folding process is error prone and organisms have evolved ''editing'' or quality control (QC) systems to assist in the folding, maintenance and, when necessary, selective removal of damaged proteins. In fact, there is growing evidence that failure of these QC-systems contributes to a number of disease states (5-8). This chapter describes our current understanding of the nature and mechanisms of the protein quality control systems in the cytosol of bacteria. Parallel systems are exploited in the cytosol and mitochondria of eukaryotes to prevent the accumulation of misfolded proteins.

  9. TALE-induced bHLH transcription factors that activate a pectate lyase contribute to water soaking in bacterial spot of tomato

    Science.gov (United States)

    Schwartz, Allison R.; Morbitzer, Robert; Lahaye, Thomas; Staskawicz, Brian J.

    2017-01-01

    AvrHah1 [avirulence (avr) gene homologous to avrBs3 and hax2, no. 1] is a transcription activator-like (TAL) effector (TALE) in Xanthomonas gardneri that induces water-soaked disease lesions on fruits and leaves during bacterial spot of tomato. We observe that water from outside the leaf is drawn into the apoplast in X. gardneri-infected, but not X. gardneriΔavrHah1 (XgΔavrHah1)-infected, plants, conferring a dark, water-soaked appearance. The pull of water can facilitate entry of additional bacterial cells into the apoplast. Comparing the transcriptomes of tomato infected with X. gardneri vs. XgΔavrHah1 revealed the differential up-regulation of two basic helix–loop–helix (bHLH) transcription factors with predicted effector binding elements (EBEs) for AvrHah1. We mined our RNA-sequencing data for differentially up-regulated genes that could be direct targets of the bHLH transcription factors and therefore indirect targets of AvrHah1. We show that two pectin modification genes, a pectate lyase and pectinesterase, are targets of both bHLH transcription factors. Designer TALEs (dTALEs) for the bHLH transcription factors and the pectate lyase, but not for the pectinesterase, complement water soaking when delivered by XgΔavrHah1. By perturbing transcriptional networks and/or modifying the plant cell wall, AvrHah1 may promote water uptake to enhance tissue damage and eventual bacterial egression from the apoplast to the leaf surface. Understanding how disease symptoms develop may be a useful tool for improving the tolerance of crops from damaging disease lesions. PMID:28100489

  10. Factors Controlling the Distribution of Trace Metals in Macroalgae

    Institute of Scientific and Technical Information of China (English)

    王宝利; 刘丛强

    2004-01-01

    This paper presents the concentrations of trace metals (Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb) in macroalgae from five areas. Significant differences were noticed in trace metal concentration in macroalgae, and a large range of variations between the minimum and maximum concentrations of trace metals was found. Trace metals detected in macroalgae generally occur in adsorbed and absorbed forms. Environmental and biological factors jointly control the trace metal compositions and concentrations in macroalgae. The complexity and variation of these factors cause significant differences in trace metal concentrations in macroalgae. Environmental factors play a more important role in controlling trace metal compositions and concentrations when external available trace metals are beyond requirement for algal metabolism and growth, especially for non-essential trace metals; however, when the external available trace metals just satisfy the needs of algal metabolism and growth, biological factors would play a more important role, especially for essential trace metals. Interactions among the trace metals can also influence their compositions and concentrations in macroalgae. It is also discussed how to make macroalgae as an excellent biomonitor for trace metals.

  11. Artificially constructed quorum-sensing circuits are used for subtle control of bacterial population density.

    Science.gov (United States)

    Wang, Zhaoshou; Wu, Xin; Peng, Jianghai; Hu, Yidan; Fang, Baishan; Huang, Shiyang

    2014-01-01

    Vibrio fischeri is a typical quorum-sensing bacterium for which lux box, luxR, and luxI have been identified as the key elements involved in quorum sensing. To decode the quorum-sensing mechanism, an artificially constructed cell-cell communication system has been built. In brief, the system expresses several programmed cell-death BioBricks and quorum-sensing genes driven by the promoters lux pR and PlacO-1 in Escherichia coli cells. Their transformation and expression was confirmed by gel electrophoresis and sequencing. To evaluate its performance, viable cell numbers at various time periods were investigated. Our results showed that bacteria expressing killer proteins corresponding to ribosome binding site efficiency of 0.07, 0.3, 0.6, or 1.0 successfully sensed each other in a population-dependent manner and communicated with each other to subtly control their population density. This was also validated using a proposed simple mathematical model.

  12. Artificially constructed quorum-sensing circuits are used for subtle control of bacterial population density.

    Directory of Open Access Journals (Sweden)

    Zhaoshou Wang

    Full Text Available Vibrio fischeri is a typical quorum-sensing bacterium for which lux box, luxR, and luxI have been identified as the key elements involved in quorum sensing. To decode the quorum-sensing mechanism, an artificially constructed cell-cell communication system has been built. In brief, the system expresses several programmed cell-death BioBricks and quorum-sensing genes driven by the promoters lux pR and PlacO-1 in Escherichia coli cells. Their transformation and expression was confirmed by gel electrophoresis and sequencing. To evaluate its performance, viable cell numbers at various time periods were investigated. Our results showed that bacteria expressing killer proteins corresponding to ribosome binding site efficiency of 0.07, 0.3, 0.6, or 1.0 successfully sensed each other in a population-dependent manner and communicated with each other to subtly control their population density. This was also validated using a proposed simple mathematical model.

  13. Programmable control of bacterial gene expression with the combined CRISPR and antisense RNA system.

    Science.gov (United States)

    Lee, Young Je; Hoynes-O'Connor, Allison; Leong, Matthew C; Moon, Tae Seok

    2016-03-18

    A central goal of synthetic biology is to implement diverse cellular functions by predictably controlling gene expression. Though research has focused more on protein regulators than RNA regulators, recent advances in our understanding of RNA folding and functions have motivated the use of RNA regulators. RNA regulators provide an advantage because they are easier to design and engineer than protein regulators, potentially have a lower burden on the cell and are highly orthogonal. Here, we combine the CRISPR system from Streptococcus pyogenes and synthetic antisense RNAs (asRNAs) in Escherichia coli strains to repress or derepress a target gene in a programmable manner. Specifically, we demonstrate for the first time that the gene target repressed by the CRISPR system can be derepressed by expressing an asRNA that sequesters a small guide RNA (sgRNA). Furthermore, we demonstrate that tunable levels of derepression can be achieved (up to 95%) by designing asRNAs that target different regions of a sgRNA and by altering the hybridization free energy of the sgRNA-asRNA complex. This new system, which we call the combined CRISPR and asRNA system, can be used to reversibly repress or derepress multiple target genes simultaneously, allowing for rational reprogramming of cellular functions.

  14. Understanding disease control: influence of epidemiological and economic factors

    CERN Document Server

    Oles, Katarzyna; Kleczkowski, Adam

    2011-01-01

    We present a local spread model of disease transmission on a regular network and compare different control options ranging from treating the whole population to local control in a well-defined neighborhood of an infectious individual. Comparison is based on a total cost of epidemic, including cost of palliative treatment of ill individuals and preventive cost aimed at vaccination or culling of susceptible individuals. Disease is characterized by pre- symptomatic phase which makes detection and control difficult. Three general strategies emerge, global preventive treatment, local treatment within a neighborhood of certain size and only palliative treatment with no prevention. The choice between the strategies depends on relative costs of palliative and preventive treatment. The details of the local strategy and in particular the size of the optimal treatment neighborhood weakly depends on disease infectivity but strongly depends on other epidemiological factors. The required extend of prevention is proportiona...

  15. Bacterial Sialidase

    Science.gov (United States)

    2004-01-01

    Data shows that elevated sialidase in bacterial vaginosis patients correlates to premature births in women. Bacterial sialidase also plays a significant role in the unusual colonization of Pseudomonas aeruginosa in cystic fibrosis patients. Crystals of Salmonella sialidase have been reproduced and are used for studying the inhibitor-enzyme complexes. These inhibitors may also be used to inhibit a trans-sialidase of Trypanosome cruzi, a very similar enzyme to bacterial sialidase, therefore preventing T. cruzi infection, the causitive agent of Chagas' disease. The Center for Macromolecular Crystallography suggests that inhibitors of bacterial sialidases can be used as prophylactic drugs to prevent bacterial infections in these critical cases.

  16. Cooperative research for human factors review of advanced control rooms

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jung Woon; Park, Jae Chang; Lee, Yong Hee; Oh, In Seok; Lee, Hyun Chul

    2000-12-01

    This project has been performed as cooperative research between KAERI and USNRC. Human factors issues related to soft controls, which is one of key features of advanced HSI, are identified in this project. The issues are analyzed for the evaluation approaches in either experimental or analytical ways. Also, issues requiring additional researches for the evaluation of advanced HSI are identified in the areas of advanced information systems design, computer-based procedure systems, soft controls, human systems interface and plant modernization process, and maintainability of digital systems. The issues are analyzed to discriminate the urgency of researches on it to high, medium, and low levels in consideration of advanced HSI development status in Korea, and some of the issues that can be handled by experimental researches are identified. Additionally, an experimental study is performed to compare operator's performance on human error detection in advanced control rooms vs. in conventional control rooms. It is found that advanced control rooms have several design characteristics hindering operator's error detection performance compared to conventional control rooms.

  17. Efficacy and safety of oral tinidazole and metronidazole in treatment of bacterial vaginosis: a randomized control trial

    Directory of Open Access Journals (Sweden)

    Zahra Abbaspoor

    2014-05-01

    Full Text Available Aims: Oral metronidazole 500 mg twice a day for one week is currently the treatment of choice for bacterial vaginosis (BV. Complete treatment by this regimen takes time and occurs less often. This drug has significant side effects too. Using a drug in the shortest treatment course may increases the success of treatment. To evaluate the effectiveness and safety of oral tinidazole compare to metronidazole in treatment of BV.Methods: In this randomized, controlled, double-blind, comparative, clinical trial, 110 non-pregnant women aged between 15-45 years with confirmed diagnosis of BV by Amsels criteria were randomly assigned to receive either 2 g tinidazole tablet once daily for 2 days (n=55 or 500 mg metronidazole table twice daily for 7 days (n=55.The cure and recurrence rate were evaluated in both groups after 2 and 4 weeks follow up visits. For statistical analysis t-test,   test, fisher's exact test and Mann-Whitney test were used.Results: The results showed that cure rate after 2 weeks in tinidazole tablet group was 84.6٪ and in metronidazole group was 85.4٪ (p=0.9, and after 4 weeks recurrence rate in tinidazole and metronidazole groups was 6.9٪and 12.1٪respectively (P=0.3.Conclusions: Tinidazole table 2 g once daily for 2 days is as effective as metronidazole tablet 500 mg twice a day for 7 days in treatment of BV.

  18. Proteome profiles of vaginal fluids from women affected by bacterial vaginosis and healthy controls: outcomes of rifaximin treatment.

    Science.gov (United States)

    Cruciani, Federica; Wasinger, Valerie; Turroni, Silvia; Calanni, Fiorella; Donders, Gilbert; Brigidi, Patrizia; Vitali, Beatrice

    2013-11-01

    This study was designed to characterize the proteome of vaginal fluid (VF) from women with bacterial vaginosis (BV) in comparison with that from healthy women, and to evaluate the effect exerted by rifaximin vaginal tablets. Women with BV (n = 39) and matched healthy controls (n = 41) were included in the study. BV patients were distributed among four groups receiving different doses of rifaximin. Vaginal rinsings were collected at the screening visit from all the participants and at a follow-up visit from BV-affected women. The VF proteome was analysed by tandem mass spectrometry using an Orbitrap mass analyser. A large number of human proteins were differentially expressed in women with BV in comparison with healthy women (n = 118) and in BV-affected women treated with rifaximin (n = 284). In both comparisons, a high proportion of the dysregulated proteins (∼20%) were involved in the innate immune response. Twenty-one of 24 proteins increased in abundance in women with BV versus healthy women and 31/59 proteins decreased after rifaximin treatment, suggesting a general reduction of the immune response resulting from the therapy. Major changes in protein abundance were found following treatment with 25 mg of rifaximin once daily for 5 days. BV is associated with a massive change in the VF proteome, mainly regarding the abundance of proteins involved in the innate immune response. Rifaximin at a dosage of 25 mg for 5 days modulated the vaginal proteome, counteracting the alterations associated with the BV condition.

  19. Gelatin methacrylate microspheres for controlled growth factor release.

    Science.gov (United States)

    Nguyen, Anh H; McKinney, Jay; Miller, Tobias; Bongiorno, Tom; McDevitt, Todd C

    2015-02-01

    Gelatin has been commonly used as a delivery vehicle for various biomolecules for tissue engineering and regenerative medicine applications due to its simple fabrication methods, inherent electrostatic binding properties, and proteolytic degradability. Compared to traditional chemical cross-linking methods, such as the use of glutaraldehyde (GA), methacrylate modification of gelatin offers an alternative method to better control the extent of hydrogel cross-linking. Here we examined the physical properties and growth factor delivery of gelatin methacrylate (GMA) microparticles (MPs) formulated with a wide range of different cross-linking densities (15-90%). Less methacrylated MPs had decreased elastic moduli and larger mesh sizes compared to GA MPs, with increasing methacrylation correlating to greater moduli and smaller mesh sizes. As expected, an inverse correlation between microparticle cross-linking density and degradation was observed, with the lowest cross-linked GMA MPs degrading at the fastest rate, comparable to GA MPs. Interestingly, GMA MPs at lower cross-linking densities could be loaded with up to a 10-fold higher relative amount of growth factor than conventional GA cross-linked MPs, despite the GA MPs having an order of magnitude greater gelatin content. Moreover, a reduced GMA cross-linking density resulted in more complete release of bone morphogenic protein 4 and basic fibroblast growth factor and accelerated release rate with collagenase treatment. These studies demonstrate that GMA MPs provide a more flexible platform for growth factor delivery by enhancing the relative binding capacity and permitting proteolytic degradation tunability, thereby offering a more potent controlled release system for growth factor delivery.

  20. Based on Multi-Factors Grey Prediction Control for Elevator Velocity Modulation

    OpenAIRE

    2012-01-01

    This paper uses the double-factors grey prediction and the fuzzy controller for the elevator car speed control. We introduce double-factors grey control to predict car vibration for elevator speed during the operation. Simulation results show that based on multi-factors gray prediction fuzzy PI control for elevator velocity modulation system closer than simple gray fuzzy PI control elevator speed control system to the actual operation. The control effect of double factors grey fuzzy PI contro...

  1. Bacterial toxins induce sustained mRNA expression of the silencing transcription factor klf2 via inactivation of RhoA and Rhophilin 1.

    Science.gov (United States)

    Dach, Kristina; Zovko, Josip; Hogardt, Michael; Koch, Isabel; van Erp, Katrin; Heesemann, Jürgen; Hoffmann, Reinhard

    2009-12-01

    Yersiniae bearing the Yersinia virulence plasmid pYV impact the transcriptome of J774A.1 macrophage-like cells in two distinct ways: (i) by suppressing, in a Yersinia outer protein P (YopP)-dependent manner, the induction of inflammatory response genes and (ii) by mRNA induction of the silencing transcription factor klf2. Here we show that klf2 induction by Yersinia enterocolitica occurs in several cell lines of macrophage and squamous and upper gastrointestinal epithelial origin as well as in bone marrow-derived dendritic cells. Several strains of Pseudomonas aeruginosa and Staphylococcus aureus are equally effective as Y. enterocolitica in inducing klf2 expression. Screening of mutant strains or incubation with recombinant toxins identified the rho-inactivating toxins YopT from Yersinia spp., ExoS from Pseudomonas aeruginosa, EDIN-B from Staphylococcus aureus, and C3bot from Clostridium botulinum as bacterial inducers of klf2 mRNA. klf2 mRNA induction by these toxins does not require de novo protein synthesis. Serum response factor or actin depolymerization does not seem to be involved in regulating klf2 expression in response to bacterial infection. Instead, short hairpin RNA-mediated inactivation of RhoA and its effector rhophilin 1 is sufficient to induce long-term klf2 expression. Thus, bacteria exploit the RhoA-rhophilin signaling cascade to mediate sustained expression of the immunosuppressive transcription factor klf2.

  2. Risk Factors For Ectopic Pregnancy : A Case Control Study

    Directory of Open Access Journals (Sweden)

    Deshmukh J.S

    1999-01-01

    Full Text Available Research question: Which are the risk factors for ectopic pregnancy . Objective: To study the strength of association between hypothesised risk factors and ectopic pregnancy. Study design: Unmatched case- control study. Setting: Government Medical College, Hospital, Nagpur. Participants: 133 cases of ectopic pregnancy and equal number of controls (non pregnant women admitted to study hospital. Study variables : Pelvic inflammatory diseases, sexually transmitted diseases, IUD use at conception , past use of IUD, prior ectopic pregnancy, OC pills use at the time of conception, past use of OC pills, induced abortion, spontaneous abortion, infertility and pelvic and abdominal surgery. Statistical analysis: Odds ratios & their 95% CI, Pearson’s chi square test, unconditional logistic regression analysis and population attributable risk proportion. Results : Use of IUD at conception, prior ectopic pregnancy , pelvic inflammatory disease, sexually transmitted diseases, infertility, OC pills use at the time of conception, past use of IUD and induced abortion were found to be significantly associated with ectopic pregnancy. Conclusion: Identification of these risk factors for etopic pregnancy shall help in early detection and appropriate management in an individual case and it may help in devising a comprehensive preventive strategy for ectopic pregnancy

  3. Social and cultural factors in the successful control of tuberculosis.

    Science.gov (United States)

    Rubel, A J; Garro, L C

    1992-01-01

    The burden of tuberculosis on the public health is staggering. Worldwide, annual incidence of new cases is estimated to be about 8 million. Almost 3 million deaths occur yearly. Early case identification and adherence to treatment regimens are the remaining barriers to successful control. In many nations, however, fewer than half those with active disease receive a diagnosis, and fewer than half those beginning treatment complete it. The twin problems of delay in seeking treatment and abandonment of a prescribed regimen derive from complex factors. People's confusion as to the implications of the tuberculosis symptoms, costs of transportation to clinic services, the social stigma that attaches to tuberculosis, the high cost of medication, organizational problems in providing adequate followup services, and patients' perception of clinic facilities as inhospitable all contribute to the complexity. Sociocultural factors are emphasized in this report because hitherto they have not been adequately explored. Salient among those sociocultural factors is the health culture of the patients. That is, the understanding and information people have from family, friends, and neighbors as to the nature of a health problem, its cause, and its implications. A knowledge of the health culture of their patients has become a critical tool if tuberculosis control programs are to be successful. Several anthropological procedures are recommended to help uncover the health culture of people served by tuberculosis clinics.

  4. Papel del factor tumoral en el control de las reservas grasas y la obesidad.

    OpenAIRE

    M Bullo Bonet; P Garcia-Lorda; JM Argilés; J Salas Salvado

    2000-01-01

    Papel del factor tumoral en el control de las reservas grasas y la obesidad. The role of tumor necrosis factor in the control of fat reserve and obesity. Papel del factor tumoral en el control de las reservas grasas y la obesidad. The role of tumor necrosis factor in the control of fat reserve and obesity.

  5. Bacterial translocation as a source of Dacron-graft contamination in experimental aortic operation: the importance of controlling SIRS.

    Science.gov (United States)

    Lozano, Francisco S; Cascajo, Carlos; García-Sánchez, Enrique; Barros, Marcello B; García-Criado, Francisco J; Parreño, Felipe; García-Sánchez, José Elias; Gómez-Alonso, Alberto

    2006-07-01

    Several experimental studies have shown the beneficial effects of nitric oxide (NO) in the modulation of the systemic inflammatory response syndrome (SIRS). Nitric oxide is involved in and affects almost all stages in the development of inflammation. We have attempted to ascertain whether the nitric oxide donor molsidomine prevents aortic graft contamination through control of the SIRS and a decrease in bacterial translocation (BT). Twenty-four mini-pigs were divided into 4 groups. The animals were subjected to suprarenal aortic/iliac cross-clamping (for 30 minutes) and by-pass with a Dacron-collagen prosthetic graft impregnated in rifampicin. Groups: 1) sham (aortic dissection alone); 2) cross-clamping and bypass; 3) hemorrhage of 40% of total blood volume before cross-clamping and by-pass; and 4) the same as in group 3 but also including the administration of the NO donor molsidomine (4 mg/kg) 5 minutes before cross-clamping. 1) bacteriology of mesenteric lymph nodes (MLN), kidney, blood, and prosthesis; 2) serum TNF-alpha (ELISA); and 3) iNOS expression in kidney and liver (Western blot). Aortic cross-clamping with or without hemorrhage was associated with BT in 80% and 100% of the animals, respectively. About 86% of the bacteria isolated in the graft were also present in MLN. This contamination coincided with an increase in TNF-alpha and with a greater expression of iNOS. Molsidomine administration decreased TNF-alpha and iNOS, decreased BT (from 100% to 20% of the animals), and decreased graft contamination (from 83% to 20%). The present model induces high levels of BT and SIRS, both acted as sources of contamination for the implanted Dacron graft. Molsidomine administration decreased the presence of bacteria in the graft by controlling BT and modulating SIRS.

  6. Risk factors for otitis media in children with special emphasis on the role of colonization with bacterial airway pathogens: the Generation R study

    Science.gov (United States)

    Labout, Joost A. M.; Duijts, Liesbeth; Lebon, Ankie; de Groot, Ronald; Hofman, Albert; Jaddoe, Vincent V. W.; Verbrugh, Henri A.; Hermans, Peter W. M.

    2010-01-01

    Acute otitis media is the most frequent diagnosis in children visiting physicians’ offices. Risk factors for otitis media have been widely studied. Yet, the correlation between bacterial carriage and the development of otitis media is not entirely clear. Our aim was to study in a population-based prospective cohort the risk factors for otitis media in the second year of life with special emphasis on the role of colonization with Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. The study was embedded in the Generation R Study. Data on risk factors and doctor-diagnosed otitis media were obtained by midwives, hospital registries and postal questionnaires in the whole cohort (n = 7,295). Nasopharyngeal swabs were obtained at the age of 1.5, 6 and 14 months in the focus cohort (n = 1,079). Of these children, 2,515 (47.2%) suffered at least one period of otitis media in their second year of life. The occurrence of otitis media during the follow-up period in the first 6 months of life and between 6 and 12 months of age was associated with the risk of otitis media in the second year of life (aOR, 1.83 95% CI 1.24–2.71 and aOR 2.72, 95% CI 2.18–3.38, respectively). Having siblings was associated with an increased risk for otitis media in the second year of life (aOR 1.42, 95% CI 1.13–1.79). No associations were found between bacterial carriage in the first year of life and otitis media in the second year of life. In our study, otitis media in the first year of life is an independent risk factor for otitis media in the second year of life. Surprisingly, bacterial carriage in the first year of life did not add to this risk. Moreover, no association was observed between bacterial carriage in the first year of life and otitis in the second year of life. PMID:20821039

  7. Risk factors for otitis media in children with special emphasis on the role of colonization with bacterial airway pathogens: the Generation R study.

    Science.gov (United States)

    Labout, Joost A M; Duijts, Liesbeth; Lebon, Ankie; de Groot, Ronald; Hofman, Albert; Jaddoe, Vincent V W; Verbrugh, Henri A; Hermans, Peter W M; Moll, Henriëtte A

    2011-01-01

    Acute otitis media is the most frequent diagnosis in children visiting physicians' offices. Risk factors for otitis media have been widely studied. Yet, the correlation between bacterial carriage and the development of otitis media is not entirely clear. Our aim was to study in a population-based prospective cohort the risk factors for otitis media in the second year of life with special emphasis on the role of colonization with Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. The study was embedded in the Generation R Study. Data on risk factors and doctor-diagnosed otitis media were obtained by midwives, hospital registries and postal questionnaires in the whole cohort (n = 7,295). Nasopharyngeal swabs were obtained at the age of 1.5, 6 and 14 months in the focus cohort (n = 1,079). Of these children, 2,515 (47.2%) suffered at least one period of otitis media in their second year of life. The occurrence of otitis media during the follow-up period in the first 6 months of life and between 6 and 12 months of age was associated with the risk of otitis media in the second year of life (aOR, 1.83 95% CI 1.24-2.71 and aOR 2.72, 95% CI 2.18-3.38, respectively). Having siblings was associated with an increased risk for otitis media in the second year of life (aOR 1.42, 95% CI 1.13-1.79). No associations were found between bacterial carriage in the first year of life and otitis media in the second year of life. In our study, otitis media in the first year of life is an independent risk factor for otitis media in the second year of life. Surprisingly, bacterial carriage in the first year of life did not add to this risk. Moreover, no association was observed between bacterial carriage in the first year of life and otitis in the second year of life.

  8. Risk factors for bacterial infection in leucopenia patients with gastrointestinal fistula%低白细胞血症肠瘘病人细菌感染危险因素分析

    Institute of Scientific and Technical Information of China (English)

    周郑; 任建安; 刘海燕; 顾国胜; 黎介寿

    2011-01-01

    目的 分析导致低白细胞血症的肠瘘病人发生细菌感染的危险因素.方法 对2007年1月至2008年6月南京大学医学院临床学院南京军区南京总医院诊治98例肠瘘病人的临床资料进行回顾性分析.98例病人分为研究组和对照组,研究组由25例发生细茵感染的低白细胞血症肠瘘病人组成,对照组由73例细菌感染阴性的低白细胞血症肠瘘病人组成.结果 导致低白细胞血症肠瘘病人发生细菌感染的唯一独立危险因素是中心静脉置管,在研究组的置管率为40%,在对照组的置管率仅为5.48%.其他危险因素包括:肝功能不全、机械通气和导尿管留置.导致细菌感染阳性的低白细胞血症肠瘘病人发生死亡的危险因素为肾功能不全和导尿管留置.结论 中心静脉置管是导致低白细胞血症肠瘘病人发生细菌感染的最主要危险因素.这一结论有助于临床医师采取更有效的针对性治疗措施以降低细菌感染的发生率,改善肠瘘病人的预后.%Objective To find risk factors for bacterial infection in leucopenia patients with gastrointestinal fistula.Methods The clinical data of 98 leucopenia patients with gastrointestinal fistula admitted between January 2007 and June 2008 at the General Surgical Institute of Jinling Hospital of Nanjing Univeristy were analyzed retrospectively.Cases consisted of 25 patients with bacterial infection positive and controls consisted of 73 patients with bacterial infection negative.Results The only independent determinant was central vein catheter, with in cases, 40% of patients had central vein catheter, whereas only 5.48% of patients in controls had central vein catheter.Other risk factors included hepatic dysfunction, mechanical ventilation and urinary catheter.The factors most strongly associated with mortality in controls were renal insufficiency and urinary catheter.Conclusion Central vein catheter is by far the most important predisposing

  9. Rifaximin has minor effects on bacterial composition, inflammation and bacterial translocation in cirrhosis; a randomized trial

    DEFF Research Database (Denmark)

    Kimer, Nina; Pedersen, Julie S.; Tavenier, Juliette

    2017-01-01

    by 16S rRNA gene sequencing. RESULTS: Circulating markers of inflammation, including TNFα, interleukin-6, 10 and 18, Stromal cell-derived factor 1-α, transforming growth factor β-1 and high sensitivity CRP, were unaltered by rifaximin treatment. Rifaximin altered abundance of bacterial taxa in blood...... with rifaximin may reduce bacterial translocation (BT) and decrease inflammation. In a randomized, placebo-controlled trial investigated the effects of rifaximin on inflammation and BT in decompensated cirrhosis. METHODS: Fifty-four out-patients with cirrhosis and ascites were randomized, mean age 56 years (±8...

  10. Frequency control system based on power factor control of asynchronous motor

    Institute of Scientific and Technical Information of China (English)

    MENG Qing-chun; YANG Fei-xia; REN Zhi-ling

    2005-01-01

    Deduced the relationship between the power factor (PF) and the angular frequency according to the simplified equivalent circuit of asynchronous motor, forming a power factor auto-control system. An anti-interference circuit was also introduced in the middle voltage link of inverter to avoid the shift of the optimum PF point caused by the change of the load and the reliable run of the control system was assured. The experiment results show that it has a good self-adaptation in the whole scope of speed adjustment and an obvious economization on energy while it runs under load.

  11. Shoreline as a controlling factor in commercial shrimp production

    Science.gov (United States)

    Faller, K. H. (Principal Investigator)

    1979-01-01

    The author has identified the following significant results. An ecological model was developed that relates marsh detritus export and shrimp production. It was based on the hypothesis that the shoreline is a controlling factor in the production of shrimp through regulation of detritus export from the marsh. LANDSAT data were used to develop measurement of shoreline length and areas of marsh having more than 5.0 kilometers of shoreline per square kilometer of area for the Louisiana coast, demonstrating the capability of remote sensing to provide important geographic information. These factors were combined with published tidal ranges and salinities to develop a mathematical model that predicted shrimp production for nine geographic units of the Louisiana coast, as indicated by the long term average commercial shrimp yield.

  12. Revisiting factors controlling methane emissions from high-Arctic tundra

    DEFF Research Database (Denmark)

    Mastepanov, M.; Sigsgaard, C.; Tagesson, T.;

    2013-01-01

    with measurements made outside the growing season, are underrepresented in the literature. Here we present results of 5 yr (2006-2010) of automatic chamber measurements at a high-Arctic location in Zackenberg, NE Greenland, covering both the growing seasons and two months of the following freeze-in periods...... explained by high seasonality of both variables, and weakly correlated with the water table. The greatest variability in fluxes between the study years was observed during the first part of the growing season. Somewhat surprisingly, this variability could not be explained by commonly known factors...... controlling methane emission, i.e. temperature and water table position. Late in the growing season CH4 emissions were found to be very similar between the study years (except the extremely dry 2010) despite large differences in climatic factors (temperature and water table). Late-season bursts of CH4...

  13. Multiple Sclerosis Associated Risk Factors: A Case-Control Study

    Directory of Open Access Journals (Sweden)

    Jalal POOROLAJAL

    2015-11-01

    Full Text Available Background: Hamadan Province is one of the high-risk regions in Iran for Multiple sclerosis (MS. A majority of the epidemiological studies conducted in Iran addressing MS are descriptive. This study was conducted to assess MS and its associated risk factors in Hamadan Province, the west of Iran.Methods: This case-control study compared 100 patients with MS (case group and 100 patients with acute infectious diseases (control group from September 2013 to March 2014. A checklist was used to assess the demographic, medical, and family history of the patients. The Friedman-Rosenman questionnaire was also used to assess personality type. Statistical analysis was performed using logistic regression model with Stata 11 software program.Results: The adjusted odds ratio (OR estimate of MS was 4.37 (95% CI: 2.33, 8.20 for females compared to males; 0.15 (95% CI: 0.06, 0.43 for people aged above 50 years compared to aged 14 to 29 years; 0.44 (95% CI: 0.21, 0.91 for overweight or obese people compared to normal weights. Crude OR indicated a significant association between the occurrence of MS and exclusive breast feeding, season of birth, and smoking. However, the association was not statistically significant after adjustment for other covariates.Conclusion: The risk of MS is significantly lower in male gender, obese/overweight, and old people. Furthermore, non-smoking, non-exclusive breast-feeding, and born in autumn may increase the risk of MS but need further investigation. However, long-term large prospective cohort studies are needed to investigate the true effect of the potential risk factors on MS. Keywords: Multiple sclerosis, Risk factors, Case-control study, Iran

  14. Three controllable factors of steady operation of EGSB reactor

    Institute of Scientific and Technical Information of China (English)

    LI Hui-li; LU Bing-nan; LI Fang

    2008-01-01

    The bench- scale EGSB (expanded granular sludge bed) reactor was operated to study the effect of sludge loading rate, pH value and nutrient element on the operation of the EGSB reactor and the control rule of these factors. Continuous flow was used to treat synthetic wastewater containing dextrose and beer, and the temperature of reactor was controlled at mesophiles temperature (33 ℃). The experimental results demonstrated trolled by adding sodium bicarbonate, the proper additive quantity was 1000-1200 mg/L; the additive quantity wastewater with 400-5000 mg/L COD concentration. The COD removal efficiency was over 85%. The operation of the EGSB reactor was steady and the EGSB reactor had strong anti-shock load ability.

  15. Factors Associated with Academic Achievement in Children with Controlled Epilepsy.

    Science.gov (United States)

    Williams, Jane; Phillips, Tonya; Griebel, May L.; Sharp, Gregory B.; Lange, Bernadette; Edgar, Terence; Simpson, Pippa

    2001-06-01

    Children with epilepsy are at risk for academic underachievement. Multiple etiologies for this academic vulnerability have been suggested by past research including lower self-esteem, inattention, memory inefficiency, and lower socioeconomic status. The present study assessed 65 children (mean age = 10 years, 5 months) with well-controlled epilepsy on the four primary factors, as well as academic achievement and intelligence. A stepwise regression analysis was employed with academic achievement as the dependent variable and measures of self-esteem, attention, memory, and socioeconomic status as independent variables. When intelligence was controlled, attention was the only variable associated with achievement scores. Seizure variables including seizure type and duration of epilepsy were not associated with differences in academic performance. Findings support the importance of measuring attention skills in children with epilepsy and suggest that reduced auditory attention skills may be associated with decreased academic performance in these children.

  16. Effects of iron supplementation on dominant bacterial groups in the gut, faecal SCFA and gut inflammation: a randomised, placebo-controlled intervention trial in South African children.

    Science.gov (United States)

    Dostal, Alexandra; Baumgartner, Jeannine; Riesen, Nathalie; Chassard, Christophe; Smuts, Cornelius M; Zimmermann, Michael B; Lacroix, Christophe

    2014-08-28

    Fe supplementation is a common strategy to correct Fe-deficiency anaemia in children; however, it may modify the gut microbiota and increase the risk for enteropathogenic infection. In the present study, we studied the impact of Fe supplementation on the abundance of dominant bacterial groups in the gut, faecal SCFA concentration and gut inflammation in children living in rural South Africa. In a randomised, placebo-controlled intervention trial of 38 weeks, 6- to 11-year-old children with Fe deficiency received orally either tablets containing 50 mg Fe as FeSO₄ (n 22) for 4 d/week or identical placebo (n 27). In addition, Fe-sufficient children (n 24) were included as a non-treated reference group. Faecal samples were analysed at baseline and at 2, 12 and 38 weeks to determine the effects of Fe supplementation on ten bacterial groups in the gut (quantitative PCR), faecal SCFA concentration (HPLC) and gut inflammation (faecal calprotectin concentration). At baseline, concentrations of bacterial groups in the gut, faecal SCFA and faecal calprotectin did not differ between Fe-deficient and Fe-sufficient children. Fe supplementation significantly improved Fe status in Fe-deficient children and did not significantly increase faecal calprotectin concentration. Moreover, no significant effect of Fe treatment or time × treatment interaction on the concentrations of bacterial groups in the gut or faecal SCFA was observed compared with the placebo treatment. Also, there were no significant differences observed in the concentrations of any of the bacterial target groups or faecal SCFA at 2, 12 or 38 weeks between the three groups of children when correcting for baseline values. The present study suggests that in African children with a low enteropathogen burden, Fe status and dietary Fe supplementation did not significantly affect the dominant bacterial groups in the gut, faecal SCFA concentration or gut inflammation.

  17. 茶园土壤细菌丰度及其影响因子研究%Bacterial Abundance of Tea Garden Soils and Its Influencing Factors

    Institute of Scientific and Technical Information of China (English)

    韩文炎; 王皖蒙; 郭赟; 杨明臻; 贾仲君

    2013-01-01

      采用 Griffiths 法直接提取土壤微生物基因组 DNA,并通过实时荧光定量 PCR 技术分析土壤微生物16 S rRNA 基因数量,对茶园及其附近森林和菜园土壤的细菌丰度及其影响因素进行了研究。结果表明,茶园土壤细菌丰度在0.01×108~20.32×10816 S rRNA 基因拷贝数/g 之间,平均为3.70×10816 S rRNA 基因拷贝数/g,与酸性森林土壤大致相当,但明显低于中性菜园土壤。土壤细菌丰度与 pH 和微生物量 C 呈极显著正相关(P<0.001),但与施 N 量和茶树种植年限呈极显著负相关(P<0.01),与土壤有机 C 和全 N 含量的相关性不明显。多元回归分析表明,影响土壤细菌丰度最重要的因子是土壤 pH,其他依次为树龄和施氮量。可见,提高茶园土壤细菌数量和微生物多样性的有效办法是适当提高土壤 pH 值,同时避免过量施用氮肥;对于改植换种的老茶园,改良土壤也是必不可少的。%Bacterial abundances in tea garden and their adjacent forest and vegetable soils were investigated by real-time quantitative PCR (qPCR) as well as the factors that may affect the population size of bacterial communities. Soil DNA was extracted by using Griffiths’ method and bacterial abundance was determined by quantifying the copy number of 16S rRNA genes. The results showed that the bacterial abundance of tea garden soils ranged from 0.01×108 to 20.32×108 16 S rRNA gene copies/g (gram dry weight soil) with an average of 3.70×108 16 S rRNA gene copies/g, being similar with that in the forest soil, but far below that in the vegetable soil. The bacterial abundance in the tea garden soils was significantly and positively correlated with the soil pH and microbial biomass C (P<0.001) respectively, but significantly and negatively correlated with N application rate and age of tea plantation (P<0.01) respectively. There was no significant correlation between bacterial abundance and

  18. The Transcription Factor IRF3 Triggers “Defensive Suicide” Necrosis in Response to Viral and Bacterial Pathogens

    Directory of Open Access Journals (Sweden)

    Nelson C. Di Paolo

    2013-06-01

    Full Text Available Although molecular components that execute noninflammatory apoptotic cell death are well defined, molecular pathways that trigger necrotic cell death remain poorly characterized. Here, we show that in response to infection with adenovirus or Listeria monocytogenes, macrophages in vivo undergo rapid proinflammatory necrotic death that is controlled by interferon-regulatory factor 3 (IRF3. The transcriptional activity of IRF3 is, surprisingly, not required for the induction of necrosis, and it proceeds normally in mice deficient in all known regulators of necrotic death or IRF3 activation, including RIPK3, caspases 1, 8, or 11, STING, and IPS1/MAVS. Although L. monocytogenes triggers necrosis to promote the infection, IRF3-dependent necrosis is required for reducing pathogen burden in the models of disseminated infection with adenovirus. Therefore, our studies implicate IRF3 as a principal and nonredundant component of a physiologically regulated necrotic cell-death pathway that operates as an effective innate immune mechanism of host protection against disseminated virus infection.

  19. An Evolutionarily Conserved Plant RKD Factor Controls Germ Cell Differentiation.

    Science.gov (United States)

    Koi, Satoshi; Hisanaga, Tetsuya; Sato, Katsutoshi; Shimamura, Masaki; Yamato, Katsuyuki T; Ishizaki, Kimitsune; Kohchi, Takayuki; Nakajima, Keiji

    2016-07-11

    In contrast to animals, in which the germ cell lineage is established during embryogenesis, plant germ cells are generated in reproductive organs via reprogramming of somatic cells. The factors that control germ cell differentiation and reprogramming in plants are poorly understood. Members of the RKD subfamily of plant-specific RWP-RK transcription factors have been implicated in egg cell formation in Arabidopsis based on their expression patterns and ability to cause an egg-like transcriptome upon ectopic expression [1]; however, genetic evidence of their involvement is lacking, due to possible genetic redundancy, haploid lethality, and the technical difficulty of analyzing egg cell differentiation in angiosperms. Here we analyzed the factors that govern germ cell formation in the liverwort Marchantia polymorpha. This recently revived model bryophyte has several characteristics that make it ideal for studies of germ cell formation, such as low levels of genetic redundancy, readily accessible germ cells, and the ability to propagate asexually via gemma formation [2, 3]. Our analyses revealed that MpRKD, a single RWP-RK factor closely related to angiosperm RKDs, is preferentially expressed in developing eggs and sperm precursors in M. polymorpha. Targeted disruption of MpRKD had no effect on the gross morphology of the vegetative and reproductive organs but led to striking defects in egg and sperm cell differentiation, demonstrating that MpRKD is an essential regulator of germ cell differentiation. Together with previous findings [1, 4-6], our results suggest that RKD factors are evolutionarily conserved regulators of germ cell differentiation in land plants. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Understanding disease control: influence of epidemiological and economic factors.

    Directory of Open Access Journals (Sweden)

    Katarzyna Oleś

    Full Text Available We present a model of disease transmission on a regular and small world network and compare different control options. Comparison is based on a total cost of epidemic, including cost of palliative treatment of ill individuals and preventive cost aimed at vaccination or culling of susceptible individuals. Disease is characterized by pre-symptomatic phase, which makes detection and control difficult. Three general strategies emerge: global preventive treatment, local treatment within a neighborhood of certain size and only palliative treatment with no prevention. While the choice between the strategies depends on a relative cost of palliative and preventive treatment, the details of the local strategy and, in particular, the size of the optimal treatment neighborhood depend on the epidemiological factors. The required extent of prevention is proportional to the size of the infection neighborhood, but depends on time till detection and time till treatment in a non-nonlinear (power law. The optimal size of control neighborhood is also highly sensitive to the relative cost, particularly for inefficient detection and control application. These results have important consequences for design of prevention strategies aiming at emerging diseases for which parameters are not nessecerly known in advance.

  1. The Novel Sigma Factor-Like Regulator RpoQ Controls Luminescence, Chitinase Activity, and Motility in Vibrio fischeri

    Science.gov (United States)

    Cao, Xiaodan; Studer, Sarah V.; Wassarman, Karen; Zhang, Yuanxing; Ruby, Edward G.; Miyashiro, Tim

    2012-01-01

    ABSTRACT Vibrio fischeri, the bacterial symbiont of the Hawaiian bobtail squid, Euprymna scolopes, uses quorum sensing to control genes involved in bioluminescence, host colonization, and other biological processes. Previous work has shown that AinS/R-directed quorum sensing also regulates the expression of rpoQ (VF_A1015), a gene annotated as an RpoS-like sigma factor. In this study, we demonstrate using phylogenetics that RpoQ is related to, but distinct from, the stationary-phase sigma factor RpoS. Overexpression of rpoQ results in elevated chitinase activity but decreased motility and luminescence, three activities associated with symbiosis. The reduction in bacterial luminescence associated with the overexpression of rpoQ occurs both in culture and within the light-emitting organ of the squid host. This suppression of bioluminescence is due to the repression of the luxICDABEG promoter. Our results highlight RpoQ as a novel regulatory component, embedded in the quorum-signaling network that controls several biological processes in V. fischeri. PMID:22233679

  2. Efficacy of bacterial cellulose membrane for the treatment of lower limbs chronic varicose ulcers: a randomized and controlled trial.

    Science.gov (United States)

    Cavalcanti, Luciana Marins; Pinto, Flávia Cristina Morone; Oliveira, Glícia Maria DE; Lima, Salvador Vilar Correia; Aguiar, José Lamartine DE Andrade; Lins, Esdras Marques

    2017-01-01

    to evaluate the efficacy of Bacterial Cellulose (BC) membrane dressings in the treatment of lower limb venous ulcers. we carried out a prospective, randomized, controlled study of 25 patients with chronic venous ulcer disease in the lower limbs from the Angiology and Vascular Surgery Service of the Federal University of Pernambuco Hospital and from the Salgado Polyclinic of the County Health Department, Caruaru, Pernambuco. We randomly assigned patients to two groups: control group, receiving dressings with triglyceride oil (11 patients) and experimental group, treated with BC membrane (14 patients). We followed the patients for a period of 120 days. There was a reduction in the wound area in both groups. There were no infections or reactions to the product in any of the groups. Patients in the BC group showed decreased pain and earlier discontinuation of analgesic use. BC membrane can be used as a dressing for the treatment of varicose ulcers of the lower limbs. avaliar a eficácia de curativos com membrana de Celulose Bacteriana (CB) no tratamento de úlceras venosas de membros inferiores. estudo prospectivo, randomizado e controlado de 25 pacientes com úlceras decorrentes de doença venosa crônica nos membros inferiores provenientes do Serviço de Angiologia e Cirurgia Vascular do Hospital de Clínicas da Universidade Federal de Pernambuco e da Policlínica do Salgado da Secretaria Municipal de Saúde, Caruaru, Pernambuco. Os pacientes foram distribuídos aleatoriamente em dois grupos: grupo controle, que recebeu curativos com óleo de triglicerídeos (11 pacientes) e grupo experimental, tratado com membrana de CB (14 pacientes). Os pacientes foram acompanhados por um período de 120 dias. houve uma redução na área de ferida em ambos os grupos. Não houve infecção ou reações ao produto em nenhum dos grupos. Pacientes do grupo CB mostraram diminuição da dor e interrupção mais precoce do uso de analgésicos. a membrana de CB pode ser usada como

  3. Factors Controlling Sediment Denitrification Rates in Grassland and Forest Streams

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    Haryun Kim

    2014-01-01

    Full Text Available Sediment denitrification is an important nitrate (NO3- removal process from agricultural streams. The direct and indirect factors that control denitrification rates in tributary sediments can vary depending on the types of agricultural activities and vegetation. Our research investigated (1 tributary sediment denitrification rates in a grassland stream affected by pasture ecosystems and a forest stream affected by N fertilization; and (2 the environmental factors that determine denitrification rates in tributary sediments. The denitrification enzyme activity (DEA in grassland stream sediments is positively correlated with precipitation likely due to the increased nutrient exchange rates between stream water and sediments, and was higher than in forest stream sediments, leading to a decrease in NO3- concentration ([NO3-] in stream sediments. The DEA in riparian sediments was regulated by carbon concentrations and did not contribute to NO3- removal from the riparian sediment in grassland and forest streams. Thus, environmental factors affected by different types of agricultural activities and vegetation might regulate denitrification rates and [NO3-] in agricultural stream ecosystems.

  4. Controllability analysis of transcriptional regulatory networks reveals circular control patterns among transcription factors

    DEFF Research Database (Denmark)

    Österlund, Tobias; Bordel, Sergio; Nielsen, Jens

    2015-01-01

    Transcriptional regulation is the most committed type of regulation in living cells where transcription factors (TFs) control the expression of their target genes and TF expression is controlled by other TFs forming complex transcriptional regulatory networks that can be highly interconnected. Here...... we analyze the topology and organization of nine transcriptional regulatory networks for E. coli, yeast, mouse and human, and we evaluate how the structure of these networks influences two of their key properties, namely controllability and stability. We calculate the controllability for each network...... as a measure of the organization and interconnectivity of the network. We find that the number of driver nodes n(D) needed to control the whole network is 64% of the TFs in the E. coli transcriptional regulatory network in contrast to only 17% for the yeast network, 4% for the mouse network and 8...

  5. Amplification of pico-scale DNA mediated by bacterial carrier DNA for small-cell-number transcription factor ChIP-seq

    DEFF Research Database (Denmark)

    Jakobsen, Janus S; Bagger, Frederik O; Hasemann, Marie S

    2015-01-01

    BACKGROUND: Chromatin-Immunoprecipitation coupled with deep sequencing (ChIP-seq) is used to map transcription factor occupancy and generate epigenetic profiles genome-wide. The requirement of nano-scale ChIP DNA for generation of sequencing libraries has impeded ChIP-seq on in vivo tissues of low...... cell numbers. RESULTS: We describe a robust, simple and scalable methodology for ChIP-seq of low-abundant cell populations, verified down to 10,000 cells. By employing non-mammalian genome mapping bacterial carrier DNA during amplification, we reliably amplify down to 50 pg of ChIP DNA from...... transcription factor (CEBPA) and histone mark (H3K4me3) ChIP. We further demonstrate that genomic profiles are highly resilient to changes in carrier DNA to ChIP DNA ratios. CONCLUSIONS: This represents a significant advance compared to existing technologies, which involve either complex steps of pre...

  6. Amplification of pico-scale DNA mediated by bacterial carrier DNA for small-cell-number transcription factor ChIP-seq

    DEFF Research Database (Denmark)

    Jakobsen, Janus S; Bagger, Frederik O; Hasemann, Marie S;

    2015-01-01

    BACKGROUND: Chromatin-Immunoprecipitation coupled with deep sequencing (ChIP-seq) is used to map transcription factor occupancy and generate epigenetic profiles genome-wide. The requirement of nano-scale ChIP DNA for generation of sequencing libraries has impeded ChIP-seq on in vivo tissues of low...... transcription factor (CEBPA) and histone mark (H3K4me3) ChIP. We further demonstrate that genomic profiles are highly resilient to changes in carrier DNA to ChIP DNA ratios. CONCLUSIONS: This represents a significant advance compared to existing technologies, which involve either complex steps of pre...... cell numbers. RESULTS: We describe a robust, simple and scalable methodology for ChIP-seq of low-abundant cell populations, verified down to 10,000 cells. By employing non-mammalian genome mapping bacterial carrier DNA during amplification, we reliably amplify down to 50 pg of ChIP DNA from...

  7. Bacteriophage Resistance Mechanisms in the Fish Pathogen Flavobacterium psychrophilum: Linking Genomic Mutations to Changes in Bacterial Virulence Factors

    DEFF Research Database (Denmark)

    Castillo, Daniel; Christiansen, Rói Hammershaimb; Dalsgaard, Inger

    2015-01-01

    requires overcoming the selection for phage resistance in the bacterial populations. Here, we analyzed resistance mechanisms in F. psychrophilum after phage exposure using whole-genome sequencing of the ancestral phage-sensitive strain 950106-1/1 and six phage-resistant isolates. The phage...... resistance and the genetic modifications were supported by direct measurements of bacteriophage adsorption rates, biofilm formation, and secretion of extracellular enzymes, which were all impaired in the resistant strains, probably due to superficial structural changes. The clustered regularly interspaced...... short palindromic repeat (CRISPR) region was unaffected in the resistant isolates and thus did not play a role as a resistance mechanism for F. psychrophilum under the current conditions. All together, the results suggest that resistance in F. psychrophilum was driven by spontaneous mutations, which...

  8. Risk factor control is key in diabetic nephropathy.

    Science.gov (United States)

    Lewis, Gareth; Maxwell, Alexander P

    2014-02-01

    Prolonged duration of diabetes, poor glycaemic control and hypertension are major risk factors for both diabetic nephropathy and cardiovascular disease. Optimising blood sugar control together with excellent control of blood pressure can reduce the risk of developing diabetic nephropathy. Diabetic nephropathy should be considered in any patient with diabetes when persistent albuminuria develops. Microalbuminuria is the earliest clinically detectable indicator of diabetic nephropathy risk. The majority of patients with diabetic nephropathy are appropriately diagnosed based on elevated urinary albumin excretion and/or reduced 0032-6518 renal function. Patients with type 2 diabetes should have annual urinary ACR measurements from the time of diabetes diagnosis while those with type 1 diabetes should commence five years after diagnosis. Blood pressure lowering to 130/80mmHg and reduction of proteinuria to diabetic nephropathy and reduces the number of cardiovascular events. Drugs that block the renin-angiotensin-aldosterone system (RAAS) are effective in reducing proteinuria, managing hypertension and reducing cardiovascular risk. Unless there are clear contraindications or intolerance all patients with diabetic nephropathy should be prescribed an ACEI or ARB. Stopping an ACEI or ARB during intercurrent illness or times of volume depletion is critically important. Patients with diabetic nephropathy should have at least yearly measurements of blood pressure, renal function and urinary ACR.

  9. Geochemical factors controlling free Cu ion concentrations in river water

    Science.gov (United States)

    Rozan, Tim F.; Benoit, Gaboury

    1999-10-01

    Copper speciation was determined monthly at seven sites on four rivers in southern New England to understand which geochemical factors control free metal ion concentrations in river water. Samples were conventionally filtered (stripping voltammetry (DPASV) was used to quantify natural organic complexation and cathodic stripping square wave voltammetry (CSSWV) to measure directly both Cu sulfide complexes and total EDTA concentrations. The results showed both dissolved organic matter (DOM) and sulfide complexation dominate Cu speciation and control the concentrations of free ion. Free Cu2+ was calculated to be in the subnanomolar range for the majority of the year. Only in the winter months, when concentrations of DOM and metal sulfides complexes were at a minimum were free metal ions directly measurable by DPASV at low nanomolar concentrations. The extent of sulfide complexation appears to be dominated by the size of headwater marshes (upstream sampling sites) and by the amount of sewage treatment plant effluent (downstream sites). DOM complexation was related to the organic matter composition and followed model organic ligands. Indirect evidence suggests variations in river water pH and Ca2+ (metal competition) has only a minor role in Cu complexation. Measured concentrations of total EDTA suggest this synthetic ligand can control Cu speciation in some highly developed watersheds; however, competition from Ni (and possibly Fe) limits the extent of this complexation.

  10. Bacterial colonization and gut development in preterm neonates

    DEFF Research Database (Denmark)

    Cilieborg, Malene S.; Boye, Mette; Sangild, Per Torp

    2012-01-01

    colonization may provide the clue to prevent NEC, and studies in infants must be combined with animal models to understand the mechanisms of the microbiota–epithelium interactions. Analyses of infant fecal samples show that the density and distribution of bacterial species are highly variable...... with no consistent effects of gestational age, delivery mode, diet or probiotic administration, while low bacterial diversity and bacterial overgrowth are commonly associated with NEC. A series of recent studies in preterm pigs show that the mucosa-associated microbiota is affected by delivery method, prematurity......Necrotizing enterocolitis (NEC) develops in 5–10% of preterm infants in association with enteral feeding and bacterial colonization. It remains unclear how diet and bacteria interact to protect or provoke the immature gastrointestinal tract. Understanding the factors that control bacterial...

  11. Risk factors for syphilis in women: case-control study.

    Science.gov (United States)

    Macêdo, Vilma Costa de; Lira, Pedro Israel Cabral de; Frias, Paulo Germano de; Romaguera, Luciana Maria Delgado; Caires, Silvana de Fátima Ferreira; Ximenes, Ricardo Arraes de Alencar

    2017-08-17

    To determine the sociodemographic, behavioral, and health care factors related to the occurrence of syphilis in women treated at public maternity hospitals. This is a case-control study (239 cases and 322 controls) with women admitted to seven maternity hospitals in the municipality of Recife, Brazil, from July 2013 to July 2014. Eligible women were recruited after the result of the VDRL (Venereal Disease Research Laboratory) under any titration. The selection of cases and controls was based on the result of the serology for syphilis using ELISA (enzyme-linked immunosorbent assay). The independent variables were grouped into: sociodemographic, behavioral, clinical and obstetric history, and health care in prenatal care and maternity hospital. Information was obtained by interview, during hospitalization, with the application of a questionnaire. Odds ratios and 95% confidence intervals were estimated using logistic regression to identify the predicting factors of the variable to be explained. The logistic regression analysis identified as determinant factors for gestational syphilis: education level of incomplete basic education or illiterate (OR = 2.02), lack of access to telephone (OR = 2.4), catholic religion (OR = 1.70 ), four or more pregnancies (OR = 2.2), three or more sexual partners in the last year (OR = 3.1), use of illicit drugs before the age of 18 (OR = 3.0), and use of illicit drugs by the current partner (OR = 1.7). Only one to three prenatal appointments (OR = 3.5) and a previous history of sexually transmitted infection (OR = 9.7) were also identified as determinant factors. Sociodemographic, behavioral, and health care factors are associated with the occurrence of syphilis in women and should be taken into account in the elaboration of universal strategies aimed at the prevention and control of syphilis, but with a focus on situations of greater vulnerability. Determinar os fatores sociodemográficos, comportamentais e de assistência à sa

  12. Factors Controlling Nanoparticle Pharmacokinetics: An Integrated Analysis and Perspective

    DEFF Research Database (Denmark)

    Moghimi, Seyed Moien; Hunter, A.C.; Andresen, T.L.

    2012-01-01

    of interrelated core and interfacial physicochemical and biological factors. Pertinent to realizing therapeutic goals, definitive maps that establish the interdependency of nanoparticle size, shape, and surface characteristics in relation to interfacial forces, biodistribution, controlled drug release, excretion......, and adverse effects must be outlined. These concepts are critically evaluated and an integrated perspective is provided on the basis of the recent application of nanoscience approaches to nanocarrier design and engineering. The future of this exciting field is bright; some regulatory-approved products...... are already on the market and many are in late-phase clinical trials. With concomitant advances in extensive computational knowledge of the genomics and epigenomics of interindividual variations in drug responses, the boundaries toward development of personalized nanomedicines can be pushed further....

  13. Factors Influencing Glycemic Control in Children with Type 1 Diabetes

    Directory of Open Access Journals (Sweden)

    Seher Çakır

    2010-05-01

    Full Text Available Introduction: There are a plenty of factors influencing glycemic control in children with type 1 diabetes mellitus (DM. The aim of this study was to determine the factors influencing metabolic control in children with type 1 DM. Materials and Method: The study was performed in 200 children with type 1 DM between the ages 6 months to 18 years. This study was conducted by interviewing individually with the children and their families and completing the questionnaires related to their demographic features and data associated with their illness. The laboratory findings and medical information of the patients from the charts were also retrospectively recorded. Results: There were a total of 200 patients including 104 (52% girls and 96 (48% boys. The mean age of the patients was 11.7 (±4.26 years. The mean duration of diabetes was 3.8 years (6 months to 14 years. Eighty-nine percent of all patients and all of the patients between 12 and 18 years of age were on intensive insulin therapy. Mean insulin dose was 0.84±0.19 units/kg/day. The mean HbA1c value was 8.8%. Body mass index (BMI mean z-score was -0.06±1.19. There were no correlations between HbA1c and the duration of diabetes or age although a positive correlation was found with insulin dose (r=0.27 p<0.01. It was found that intensive therapy did not lower HbA1c values or the risk of severe hypoglycemia. Nevertheless, there was a decrease in HbA1c values of 72 (36% patients whose therapy was converted from conventional therapy to intensive therapy (p<0.05. HbA1c values were found to be higher in patients who lived with more than 4 persons in the house, who were non-compliant to follow-up or diet, who had more than 3 symptomatic hypoglycemia in the last 6 months, who had episodes of diabetic ketoacidosis (DKA, who were adolescent at the time of diagnosis, and who were admitted with diabetic ketoacidosis at the time of diagnosis (p<0.05. Although there was a correlation between insulin doses and

  14. Effects of three approaches to standardized oral hygiene to reduce bacterial colonization and ventilator associated pneumonia in mechanically ventilated patients: a randomised control trial.

    Science.gov (United States)

    Berry, A M; Davidson, P M; Masters, J; Rolls, K; Ollerton, R

    2011-06-01

    Ventilator associated pneumonia remains an important concern in the intensive care unit (ICU). An increasing body of evidence shows that mortality and morbidity can be reduced by implementing a range of preventive strategies, including optimizing oral hygiene. The aim of this feasibility study was to test two oral hygiene strategies on the effects of microbial colonization of dental plaque with respiratory pathogens (primary outcome) and incidence of ventilator associated pneumonia (secondary outcome). A single blind randomised comparative study was conducted in a 20-bed adult intensive care unit in a university hospital. Patients with an expected duration of mechanical ventilation more than 48 h were eligible. Patients were randomised to one of three study regimens (Group A control, second hourly oral rinse with sterile water, Group B sodium bicarbonate mouth wash second hourly, and Group C twice daily irrigations with chlorhexidine 0.2% aqueous oral rinse and second hourly irrigations with sterile water). All study options included cleaning with a toothbrush and non foaming toothpaste. Data from a total of 109 patients were analyzed. Group A 43, Group B 33 and Group C 33 (mean age: 58 ± 17 years, simplified acute physiology score II: 44 ± 14 points). On admission no significant differences were found between groups for all clinical data. While Group B showed a greater trend to reduction in bacterial colonization no significant differences could be demonstrated at Day 4 of admission (p=0.302). The incidence of ventilator associated pneumonia was evenly spread between Groups B and C (5%) while Group A was only 1%. While a number of studies have advocated the use of various mouth rinses in reducing colonization of dental plaque a standardized oral hygiene protocol which includes the use of mechanical cleaning with a toothbrush may be a factor in the reduction of colonization of dental plaque with respiratory pathogens. This feasibility study provides data to

  15. Risk factors for gastroenteritis: a nested case-control study.

    Science.gov (United States)

    Rodrigo, S; Sinclair, M; Wolfe, R; Leder, K

    2011-04-01

    This nested case-control study investigated the risk factors for gastroenteritis in a cohort using rainwater as their primary domestic water source. Consumption of beef [odds ratio (OR) 2·74, 95% confidence interval (CI) 1·56-4·80], handling of raw fresh chicken in the household (OR 1·52, 95% CI 1·02-2·29) and animal contact (OR 1·83, 95% CI 1·20-2·83) were found to be significant risk factors (P>0·05). Significant protective effects were observed with raw salad prepared at home (OR 0·33, 95% CI 0·18-0·58), consumption of salami (OR 0·60, 95% CI 0·36-0·98), and shellfish (OR 0·31, 95% CI 0·14-0·67). This study provides novel insight into community-based endemic gastroenteritis showing that consumption of beef was associated with increased odds of illness and with a population attributable fraction (PAF) of 57·6%. Detecting such a high PAF for beef in a non-outbreak setting was unexpected.

  16. Transcription factor PIF4 controls the thermosensory activation of flowering

    KAUST Repository

    Kumar, S. Vinod

    2012-03-21

    Plant growth and development are strongly affected by small differences in temperature. Current climate change has already altered global plant phenology and distribution, and projected increases in temperature pose a significant challenge to agriculture. Despite the important role of temperature on plant development, the underlying pathways are unknown. It has previously been shown that thermal acceleration of flowering is dependent on the florigen, FLOWERING LOCUS T (FT). How this occurs is, however, not understood, because the major pathway known to upregulate FT, the photoperiod pathway, is not required for thermal acceleration of flowering. Here we demonstrate a direct mechanism by which increasing temperature causes the bHLH transcription factor PHYTOCHROME INTERACTING FACTOR4 (PIF4) to activate FT. Our findings provide a new understanding of how plants control their timing of reproduction in response to temperature. Flowering time is an important trait in crops as well as affecting the life cycles of pollinator species. A molecular understanding of how temperature affects flowering will be important for mitigating the effects of climate change. © 2012 Macmillan Publishers Limited. All rights reserved.

  17. The Impact of Bacterial Resistance of Animals Origin on the Bacterial Infectious Animal Disease Control%动物源细菌耐药性对动物细菌传染性疾病防治的影响

    Institute of Scientific and Technical Information of China (English)

    马苏; 高艳春

    2012-01-01

    通过阐述动物源细菌耐药性的产生及演变趋势,分析抗生素在兽医领域中的应用情况,探讨动物细菌传染性疾病的防治策略,旨在了解细菌耐药性对动物细菌传染性疾病治疗的影响,为兽用药品特别是兽用细菌疫苗的发展提供参考,促进动物卫生安全和公共卫生安全。%This review paper explains theoccurrence and evolution of bacterial resistance of animalorigin, analysis the application of antibiotics in veterinary medicine, investigate control strategies of animal infectious disease. The aim of the paper is tounderstand the impact of drug resistance on the treatment of bacterialinfectious diseases, in order to provide the guidance of development for veterinary drugs especially veterinary bacterial vaccine. It' s a certain significance to promote animal health security and public health security.

  18. Revisiting factors controlling methane emissions from high-Arctic tundra

    Directory of Open Access Journals (Sweden)

    M. Mastepanov

    2013-07-01

    Full Text Available The northern latitudes are experiencing disproportionate warming relative to the mid-latitudes, and there is growing concern about feedbacks between this warming and methane production and release from high-latitude soils. Studies of methane emissions carried out in the Arctic, particularly those with measurements made outside the growing season, are underrepresented in the literature. Here we present results of 5 yr (2006–2010 of automatic chamber measurements at a high-Arctic location in Zackenberg, NE Greenland, covering both the growing seasons and two months of the following freeze-in periods. The measurements show clear seasonal dynamics in methane emission. The start of the growing season and the increase in CH4 fluxes were strongly related to the date of snowmelt. Within each particular growing season, CH4 fluxes were highly correlated with the soil temperature (R2 > 0.75, which is probably explained by high seasonality of both variables, and weakly correlated with the water table. The greatest variability in fluxes between the study years was observed during the first part of the growing season. Somewhat surprisingly, this variability could not be explained by commonly known factors controlling methane emission, i.e. temperature and water table position. Late in the growing season CH4 emissions were found to be very similar between the study years (except the extremely dry 2010 despite large differences in climatic factors (temperature and water table. Late-season bursts of CH4 coinciding with soil freezing in the autumn were observed during at least three years. The cumulative emission during the freeze-in CH4 bursts was comparable in size with the growing season emission for the year 2007, and about one third of the growing season emissions for the years 2009 and 2010. In all three cases the CH4 burst was accompanied by a corresponding episodic increase in CO2 emission, which can compose a significant contribution to the annual CO2

  19. Risk factors in pediatric asthmatic patients. Cases and control studies.

    Directory of Open Access Journals (Sweden)

    Rafael Alejandro Gómez Baute

    2003-04-01

    Full Text Available Background: Asthma constitutes the first disease among chronic diseases in children. The morbid-mortality promoted to continue being elevated in spite of the new therapies. For this reason it is a disease with high priority for investigation in pediatric ages. Method: A control and case group study was carried out. The samples was composed by 72 asthmatic children from three General Comprehensive doctor offices from Palmira health area located in Cienfuegos Province, Cuba; and a control group of 72 children apparently healthy from the same population. A questionnaire with the different risk variables was elaborated. Odds ratio technique was used to estimate the risk. Results: low weight at birth, family history of asthma, brochiolitis antecedent and the excessive usage of antibiotics in children under 1 year old were the main risks found. Conclusions: It is conclusive that the exposure to home allergen plus a genetic favorable factor, the prematurity, and brochiolitis constituted the most outstanding elements to suffer from asthma in the population studied.

  20. Dissolution of calcite in the twilight zone: bacterial control of dissolution of sinking planktonic carbonates is unlikely.

    Directory of Open Access Journals (Sweden)

    Andrew Bissett

    Full Text Available We investigated the ability of bacterial communities to colonize and dissolve two biogenic carbonates (Foraminifera and oyster shells. Bacterial carbonate dissolution in the upper water column is postulated to be driven by metabolic activity of bacteria directly colonising carbonate surfaces and the subsequent development of acidic microenvironments. We employed a combination of microsensor measurements, scanning electron microscopy (SEM, confocal laser scanning microscopy (CLSM and image analysis and molecular documentation of colonising bacteria to monitor microbial processes and document changes in shell surface topography. Bacterial communities rapidly colonised shell surfaces, forming dense biofilms with extracellular polymeric substance (EPS deposits. Despite this, we found no evidence of bacterially mediated carbonate dissolution. Dissolution was not indicated by Ca²⁺ microprofiles, nor was changes in shell surface structure related to the presence of colonizing bacteria. Given the short time (days settling carbonate material is actually in the twilight zone (500-1000 m, it is highly unlikely that microbial metabolic activity on directly colonised shells plays a significant role in dissolving settling carbonates in the shallow ocean.

  1. Prevalent bacterial vaginosis infection - a risk factor for incident sexually transmitted infections in women in Durban, South Africa.

    Science.gov (United States)

    Abbai, Nathlee S; Reddy, Tarylee; Ramjee, Gita

    2016-12-01

    The association between bacterial vaginosis (BV) and incident sexually transmitted infections (STIs) in a cohort of high-risk women from Durban, South Africa was investigated in this study. We undertook a secondary analysis of the Methods for Improving Reproductive Health in Africa trial that assessed effectiveness of the latex diaphragm and lubricant gel on HIV prevention among women. During study visits, urine specimens were collected for testing for Neisseria gonorrhoeae, Chlamydia trachomatis and Trichomonas vaginalis The presence of BV was based on vaginal pH and wet mount test assessments. The association between BV and the risk for incident STIs was determined using the Cox proportional hazards model. Prevalence of BV was 31% in a cohort of 435 women tested at baseline. Among these women, BV was significantly associated with incident Trichomonas vaginalis (14.6 per 100 PY, p = 0.03) and Chlamydia trachomatis infections (15.8 per 100 PY, p = 0.04). BV remained a significant predictor for Trichomonas vaginalis infections even after adjusting for potential confounders such as age and marital status (HR: 1.60, 95% CI: 1.00, 2.57, p = 0.04). Our study showed an association between baseline BV infections and incident Trichomonas vaginalis and Chlamydia trachomatis infections. Women with BV infections should be counselled on the use of condoms and the risk of new STIs. © The Author(s) 2016.

  2. Crystal structure of the primary piRNA biogenesis factor Zucchini reveals similarity to the bacterial PLD endonuclease Nuc.

    Science.gov (United States)

    Voigt, Franka; Reuter, Michael; Kasaruho, Anisa; Schulz, Eike C; Pillai, Ramesh S; Barabas, Orsolya

    2012-12-01

    Piwi-interacting RNAs (piRNAs) are a gonad-specific class of small RNAs that associate with the Piwi clade of Argonaute proteins and play a key role in transposon silencing in animals. Since biogenesis of piRNAs is independent of the double-stranded RNA-processing enzyme Dicer, an alternative nuclease that can process single-stranded RNA transcripts has been long sought. A Phospholipase D-like protein, Zucchini, that is essential for piRNA processing has been proposed to be a nuclease acting in piRNA biogenesis. Here we describe the crystal structure of Zucchini from Drosophila melanogaster and show that it is very similar to the bacterial endonuclease, Nuc. The structure also reveals that homodimerization induces major conformational changes assembling the active site. The active site is situated on the dimer interface at the bottom of a narrow groove that can likely accommodate single-stranded nucleic acid substrates. Furthermore, biophysical analysis identifies protein segments essential for dimerization and provides insights into regulation of Zucchini's activity.

  3. 细菌性阴道病影响因素研究%Study of Influencing Factors of Bacterial Vaginosis

    Institute of Scientific and Technical Information of China (English)

    孙继玮; 韦旭; 周建华

    2009-01-01

    细菌性阴道病(bacterial vaginosis,BV)是由于多种致病菌大量繁殖导致阴道内微生态环境菌群与分泌物生化性质紊乱所引起的一种以阴道黏膜非炎症性表现为特征的一组疾病。对BV的真正认识是从19世纪90年代中期开始,由于对其病因的认识有限,BV曾有不同的名称,如非特异性阴道炎(non—specific vaginitis)、嗜血杆菌性阴道炎(haemophilus vaginitis)、棒状杆菌性阴道炎(corynebacterium vaginitis)、加德纳菌性阴道炎(gardnerella vaginitis GV)、厌氧菌性阴道炎(anaerobie vaginitis)等。

  4. Risk Factor Analysis of Ciprofloxacin-Resistant and Extended Spectrum Beta-Lactamases Pathogen-Induced Acute Bacterial Prostatitis in Korea.

    Science.gov (United States)

    Lee, Young; Lee, Dong Gi; Lee, Sang Hyub; Yoo, Koo Han

    2016-11-01

    The objectives of this study were to investigate risk factors and the incidence of ciprofloxacin resistance and extended-spectrum beta-lactamases (ESBL) in patients with acute bacterial prostatitis (ABP). We reviewed the medical records of 307 patients who were diagnosed with ABP between January 2006 and December 2015. The etiologic pathogens and risk factors for ciprofloxacin-resistant E. coli and ESBL-producing microbes, susceptibility to ciprofloxacin, and the incidence of ESBL in patients with ABP were described. History of prior urologic manipulation was an independent risk factor for ciprofloxacin-resistant (P = 0.005) and ESBL-producing microbes (P = 0.005). Advanced age (over 60 years) was an independent risk factor for ciprofloxacin-resistant microbes (P = 0.022). The ciprofloxacin susceptibility for Escherichia coli in groups without prior manipulation was documented 85.7%. For groups with prior manipulation, the susceptibility was 10.0%. Incidence of ESBL-producing microbes by pathogen was 3.8% for E. coli and 1.0% for Klebsiella pneumonia in the absence of manipulation group, and 20% and 33.3% in the presence of manipulation group, respectively. Initial treatment of ABP must consider patient's age and the possibility of prior manipulation to optimize patient treatment. With the high rate of resistance to fluoroquinolone, cephalosporins with amikacin, or carbapenems, or extended-spectrum penicillin with beta lactamase inhibitor should be considered as the preferred empirical ABP treatment in the patients with history of prior urologic manipulation.

  5. Evolutionary and Functional Analysis of Celiac Risk Loci Reveals SH2B3 as a Protective Factor against Bacterial Infection

    National Research Council Canada - National Science Library

    Zhernakova, Alexandra; Elbers, Clara C; Ferwerda, Bart; Romanos, Jihane; Trynka, Gosia; Dubois, Patrick C; de Kovel, Carolien G.F; Franke, Lude; Oosting, Marije; Barisani, Donatella; Bardella, Maria Teresa; Joosten, Leo A.B; Saavalainen, Paivi; van Heel, David A; Catassi, Carlo; Netea, Mihai G; Wijmenga, Cisca

    2010-01-01

    ... since the 1950s, when dietary gluten was discovered to be the triggering factor. The high prevalence of CD might suggest that genes underlying this disease may have been favored by the process of natural selection...

  6. Controle biológico da murcha bacteriana do tomateiro, por Pseudomonas spp. fluorescentes Biological control of bacterial wilt of tomato by fluorescent Pseudomonas spp

    Directory of Open Access Journals (Sweden)

    Ana Rosa Peixoto

    1997-03-01

    Full Text Available Esta revisão bibliográfica teve como objetivo avaliar o potencial de antagonismo de espécies de Pseudomonas fluorescentes a Pseudomonas solanacearum, agente causal da murcha bacteriana do tomateiro. Devido a dificuldade encontrada nas estratégias utilizadas para o controle da Murcha Bacteriana por meio de métodos convencionais, alguns outros tem sido estudados, como o uso de microrganismos benéficos. As rizobactérias vem proporcionando solução viável a algumas doenças consideradas de difícil manejo. Dentre os mecanismos que tem sido sugeridos para o controle microbiano de patógenos de plantas, através do uso de rizobactérias fluorescentes, citamse produção de antibióticos, bactericinas, enzimas titicas, competição por espaço e nutrientes. Possuem uma alta capacidade de colonização e sobrevivência no hospedeiro, falares que são importantes no estabelecimento e introdução de microrganismos na rizosfera. Estas bactérias podem também incitar um aumento no desenvolvimento e na produção do hospedeiro, sendo denominadas de rizobactérias promotoras de crescimento de plantas.This literature review has the objetive of evaluating the antagonism potential of species of florescem Pseudomonas to Pseudomonas solanacearum which is the causal agent of bacterial wilt on the tomato crop. Due to serious limitation in the ejficiency of conventional methods of contrai, other strategies have been siudied, such as the use o/beneficiai microrganisms. Rhizobacteria have shown to be a viable alternative in the contrai of some diseases of difficult managmenl. Among the mechanisms which have been suggestedfor microbian control of plantpathogens with fluorescent rhizobacteria, can be used antibiotic production, bacteriocin, uric emimes and competition for colonization and survival capacity on the host. The survival capacity is very important in the introduction and stablishment ofthe microrganisms in the rhizosphere. These bacteria can aiso

  7. IL-10 plays an important role in the control of inflammation but not in the bacterial burden in S. epidermidis CNS catheter infection.

    Science.gov (United States)

    Gutierrez-Murgas, Yenis M; Skar, Gwenn; Ramirez, Danielle; Beaver, Matthew; Snowden, Jessica N

    2016-10-13

    Shunt infection is a frequent and serious complication in the surgical treatment in hydrocephalus. Previous studies have shown an attenuated immune response to these biofilm-mediated infections. We proposed that IL-10 reduces the inflammatory response to Staphylococcus epidermidis (S. epidermidis) CNS catheter infection. In this study, a murine model of catheter-associated S. epidermidis biofilm infection in the CNS was generated based on a well-established similar model for S. aureus. The catheters were pre-coated with a clinically derived biofilm-forming strain of S. epidermidis (strain 1457) which were then stereotactically implanted into the lateral left ventricle of 8-week-old C57BL/6 and IL-10 knockout (IL-10 knockout) mice. Bacterial titers as well as cytokine and chemokine levels were measured at days 3, 5, 7, and 10 in mice implanted with sterile and S. epidermidis-coated catheters. Cultures demonstrated a catheter-associated and parenchymal infection that persisted through 10 days following infection. Cytokine analysis of the tissue surrounding the catheters revealed greater levels of IL-10, an anti-inflammatory cytokine, in the infected group compared to the sterile. In IL-10 KO mice, we noted no change in bacterial burdens, showing that IL-10 is not needed to control the infection in a CNS catheter infection model. However, IL-10 KO mice had increased levels of pro-inflammatory mediators in the tissues immediately adjacent to the infected catheter, as well as an increase in weight loss. Together our results indicate that IL-10 plays a key role in regulating the inflammatory response to CNS catheter infection but not in control of bacterial burdens. Therefore, IL-10 may be a useful therapeutic target for immune modulation in CNS catheter infection but this should be used in conjunction with antibiotic therapy for bacterial eradication.

  8. Efficiency of N2 Gas Flushing Compared to the Lactoperoxidase System at Controlling Bacterial Growth in Bovine Raw Milk Stored at Mild Temperatures

    Science.gov (United States)

    Munsch-Alatossava, Patricia; Quintyn, Romanie; De Man, Ingrid; Alatossava, Tapani; Gauchi, Jean-Pierrre

    2016-01-01

    To prevent excessive bacterial growth in raw milk, the FAO recommends two options: either cold storage or activation of the lactoperoxidase system (LPs/HT) in milk with the addition of two chemical preservatives, hydrogen peroxide (H) and thiocyanate (T). N2 gas flushing of raw milk has shown great potential to control bacterial growth in a temperature range of 6–12°C without promoting undesired side effects. Here, the effect of N2 gas (N) was tested as a single treatment and in combination with the lactoperoxidase system (NHT) on seven raw milk samples stored at 15 or 25°C. For the ratio defined as bacterial counts from a certain treatment/counts on the corresponding control, a classical Analyse of Variance (ANOVA) was performed, followed by mean comparison with the Ryan-Einot-Gabriel-Welsch multiple range test (REGWQ). Altogether, the growth inhibition was slightly but significantly higher at 25°C than at 15°C. Except for one sample, all ratios were lower for HT than for N alone; however, these differences were not judged to be significant for five samples by the REGWQ test; in the remaining two samples, N was more effective than HT in one case and less effective in the other case. This study shows that N2 gas flushing, which inhibited bacterial growth in raw milk at 15 and 25°C for 24 and 12 h, respectively, could constitute an alternative to LPs where no cold storage facilities exist, especially as a replacement for adulterating substances. PMID:27313575

  9. Efficiency of N2 gas flushing compared to the lactoperoxidase system at controlling bacterial growth in bovine raw milk stored at mild temperatures

    Directory of Open Access Journals (Sweden)

    Patricia eMunsch-Alatossava

    2016-06-01

    Full Text Available To prevent excessive bacterial growth in raw milk, the FAO recommends two options: either cold storage or activation of the lactoperoxidase system (LPs/ HT in milk with the addition of two chemical preservatives, hydrogen peroxide (H and thiocyanate (T. N2 gas flushing of raw milk has shown great potential to control bacterial growth in a temperature range of 6 to 12°C without promoting undesired side effects. Here, the effect of N2 gas (N was tested as a single treatment and in combination with the lactoperoxidase system (NHT on seven raw milk samples stored at 15 or 25°C. For the ratio defined as bacterial counts from a certain treatment/counts on the corresponding control, a classical Analyse of Variance (ANOVA was performed, followed by mean comparison with the Ryan-Einot-Gabriel-Welsch multiple range test (REGWQ. Altogether, the growth inhibition was slightly but significantly higher at 25°C than at 15°C. Except for one sample, all ratios were lower for HT than for N alone; however, these differences were not judged to be significant for five samples by the REGWQ test; in the remaining two samples, N was more effective than HT in one case and less effective in the other case. This study shows that N2 gas flushing, which inhibited bacterial growth in raw milk at 15 and 25°C for 24 and 12 h, respectively, could constitute an alternative to LPs where no cold storage facilities exist, especially as a replacement for adulterating substances.

  10. Addition of probiotics to norfloxacin does not improve efficacy in the prevention of spontaneous bacterial peritonitis: a double-blind placebo-controlled randomized-controlled trial.

    Science.gov (United States)

    Pande, Chandana; Kumar, Ashish; Sarin, Shiv Kumar

    2012-07-01

    Spontaneous bacterial peritonitis (SBP) may occur despite antibiotic prophylaxis. We investigated whether the addition of probiotics to norfloxacin enhances its efficacy in the prevention of SBP. A double-blind, randomized-controlled trial was conducted among consecutive cirrhotic patients who had either recovered from SBP (secondary prophylaxis) or who were at a high risk for the development of SBP (low ascitic fluid protein or serum bilirubin ≥ 2.5 mg/dl; primary prophylaxis). Norfloxacin 400 mg/day with probiotics capsules (Enterococcus faecalis JPC 30 million, Clostridium butyricum 2 million, Bacillus mesentericus JPC 1 million, Bacillus coagulans 50 million spores) at a dose of two capsules three times daily (group 1) or norfloxacin with a placebo (group 2) was given and the occurrence of SBP within a period of 6 months (primary endpoint) or side-effects of therapy and mortality (secondary endpoints) were recorded. From April 2005 through August 2007, 110 patients were randomized to group 1 (n=55) or group 2 (n=55) and 45 (82%) and 43 (78%) of them completed the trial, respectively. The baseline characteristics were comparable. On intention-to-treat analysis, the cumulative probability of treatment failures was similar in both the groups [19/55 (34%) in group 1 vs. 20/55 (36%) in group 2, P=0.840]. The cumulative probability of mortality was also similar [13/45 (29%) in group 1 vs. 14/43 (32%) in group 2, P=0.834]. The frequency of side-effects was also comparable. In subgroup analyses, the frequencies of SBP and deaths were similar in the two groups in the subgroups of primary and secondary prophylaxes. The presence of encephalopathy and serum bilirubin of greater than 3.65 mg/dl were found to predict mortality independently. The addition of probiotics to norfloxacin does not improve its efficacy in primary or secondary prophylaxis of SBP or in reducing the mortality in cirrhotic patients with ascites.

  11. Amphypterygium adstringens anacardic acid mixture inhibits quorum sensing-controlled virulence factors of Chromobacterium violaceum and Pseudomonas aeruginosa.

    Science.gov (United States)

    Castillo-Juárez, Israel; García-Contreras, Rodolfo; Velázquez-Guadarrama, Norma; Soto-Hernández, Marcos; Martínez-Vázquez, Mariano

    2013-10-01

    Quorum sensing (QS) is a process of bacterial cell-cell communication that controls a large number of systems affecting pathogenicity. Interrupting this communication system can provide nonvirulent pathogenic bacteria. The aim of this study was to evaluate the anti-quorum sensing (anti-QS) potential of an anacardic acids mixture isolated from Amphipterygium adstringens, a medicinal plant known as "cuachalalate", to prevent the onset of bacterial infections as an alternate to antibiotics. Initially we investigated the anti-QS activity of A. adstringens hexane extract (HE) by the inhibition of violacein production in Chromobacterium violaceum. From the active HE, an anacardic acid mixture (AAM) was obtained. The anti-quorum sensing activity of AAM was investigated by the rhamnolipid and pyocyanin production constraint as well as decrease of elastase activity, all being quorum sensing-controlled virulence factors expressed in the pathogenic bacteria Pseudomonas aeruginosa. HE induced a 91.6% of inhibition of the violecin production at 55 μg/mL concentration, whereas AAM showed 94% of inhibition at 166 μg/mL. In both cases, inhibition of violacein production did not affect the viability of the bacterium. AAM inhibited pyocyanin (86% at 200 μg/mL) and rhamnolipid (91% at 500 μg/mL) production in a dose/response form and decrease the elastase (75% at 500 μg/mL) activity in P. aeruginosa without affecting its development. Because an anacardic acids mixture isolated from A. adstringens demonstrated anti-QS, it could be further exploited for novel molecules to treat the emerging infections of antibiotic-resistant bacterial pathogens. Copyright © 2013 IMSS. Published by Elsevier Inc. All rights reserved.

  12. Risk Factors Of Low Birth Weight; Case-Control Study

    Directory of Open Access Journals (Sweden)

    Özgür Önal

    2017-06-01

    Full Text Available Low birth weight (LBW (defined as a birth weight of less than 2500 grams is associated with fetal and neonatal morbidity and mortality, impaired cognitive development, and the advent of chronic diseases in later life. The global incidenc