WorldWideScience

Sample records for pathogen survival

  1. Survival of pathogenic Escherichia coli on basil, lettuce, and spinach

    Science.gov (United States)

    The contamination of lettuce, spinach and basil with pathogenic E. coli has caused numerous illnesses over the past decade. E. coli O157:H7, E. coli O104:H4 and avian pathogenic E. coli (APECstx- and APECstx+) were inoculated on basil plants and in promix soiless substrate using drip and overhead ir...

  2. Modeling of pathogen survival during simulated gastric digestion.

    Science.gov (United States)

    Koseki, Shige; Mizuno, Yasuko; Sotome, Itaru

    2011-02-01

    The objective of the present study was to develop a mathematical model of pathogenic bacterial inactivation kinetics in a gastric environment in order to further understand a part of the infectious dose-response mechanism. The major bacterial pathogens Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella spp. were examined by using simulated gastric fluid adjusted to various pH values. To correspond to the various pHs in a stomach during digestion, a modified logistic differential equation model and the Weibull differential equation model were examined. The specific inactivation rate for each pathogen was successfully described by a square-root model as a function of pH. The square-root models were combined with the modified logistic differential equation to obtain a complete inactivation curve. Both the modified logistic and Weibull models provided a highly accurate fitting of the static pH conditions for every pathogen. However, while the residuals plots of the modified logistic model indicated no systematic bias and/or regional prediction problems, the residuals plots of the Weibull model showed a systematic bias. The modified logistic model appropriately predicted the pathogen behavior in the simulated gastric digestion process with actual food, including cut lettuce, minced tuna, hamburger, and scrambled egg. Although the developed model enabled us to predict pathogen inactivation during gastric digestion, its results also suggested that the ingested bacteria in the stomach would barely be inactivated in the real digestion process. The results of this study will provide important information on a part of the dose-response mechanism of bacterial pathogens.

  3. Modeling of Pathogen Survival during Simulated Gastric Digestion ▿

    Science.gov (United States)

    Koseki, Shige; Mizuno, Yasuko; Sotome, Itaru

    2011-01-01

    The objective of the present study was to develop a mathematical model of pathogenic bacterial inactivation kinetics in a gastric environment in order to further understand a part of the infectious dose-response mechanism. The major bacterial pathogens Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella spp. were examined by using simulated gastric fluid adjusted to various pH values. To correspond to the various pHs in a stomach during digestion, a modified logistic differential equation model and the Weibull differential equation model were examined. The specific inactivation rate for each pathogen was successfully described by a square-root model as a function of pH. The square-root models were combined with the modified logistic differential equation to obtain a complete inactivation curve. Both the modified logistic and Weibull models provided a highly accurate fitting of the static pH conditions for every pathogen. However, while the residuals plots of the modified logistic model indicated no systematic bias and/or regional prediction problems, the residuals plots of the Weibull model showed a systematic bias. The modified logistic model appropriately predicted the pathogen behavior in the simulated gastric digestion process with actual food, including cut lettuce, minced tuna, hamburger, and scrambled egg. Although the developed model enabled us to predict pathogen inactivation during gastric digestion, its results also suggested that the ingested bacteria in the stomach would barely be inactivated in the real digestion process. The results of this study will provide important information on a part of the dose-response mechanism of bacterial pathogens. PMID:21131530

  4. Effect of sunlight on the survival of pathogenic E. coli in freshwater and sea water

    DEFF Research Database (Denmark)

    Surendraraj, Alagarsamy; Farvin, Sabeena; Thampuran, N.

    2011-01-01

    An enteropathogenic group of E. coli are the emerging category of pathogen of public health significance. Several recent pathogenic E. coli outbreaks are associated with drinking water. Aquaculture, the fast emerging food production sector also poses a pathogenic EHEC outbreak risk, as it regularly...... uses cow dung, a reservoir of this organism. Hence, a experiment was set up to study the duration of survival of pathogenic E. coli under sunlight and darkness. Eight pathogenic E. coli isolates from clinical (EPEC, ETEC, EHEC, EAEC), veterinary (CTE3, CTE4) and environmental sources (ASHE3, Rao II......) were studied for their survival under sunlight and darkness in fresh water and seawater. Effect of direct sunlight on the viable but nonculturable (VBNC) state of cultures was also studied. The results of the study indicated a distinct pattern between freshwater system and seawater system. Pathogenic E...

  5. Survival of pathogenic bacteria under nutrient starvation conditions. [aboard orbiting space stations

    Science.gov (United States)

    Boyle, Michael; Ford, Tim; Mitchell, Ralph; Maki, James

    1990-01-01

    The survival of opportunistic pathogenic microorganisms in water, under nutrient-limiting conditions, has been investigated in order to ascertain whether human pathogens can survive within a water-distribution system of the kind proposed for the NASA Space Station. Cultures of a strain of pseudomonas aeruginosa and two strains of staphylococcus aureus were incubated at 10, 25, or 37 C, and samples at 1 day, 1 week, 1 month, and six weeks. While neither of the staphylococcus strains tested were detected after 1 week of starvation, the pseudomonas strain can survive in deionized water at all three temperatures.

  6. Enteric Pathogen Survival Varies Substantially in Irrigation Water from Belgian Lettuce Producers

    Science.gov (United States)

    Van Der Linden, Inge; Cottyn, Bart; Uyttendaele, Mieke; Berkvens, Nick; Vlaemynck, Geertrui; Heyndrickx, Marc; Maes, Martine

    2014-01-01

    It is accepted that irrigation water is a potential carrier of enteric pathogens, such as Salmonella and E. coli O157:H7 and, therefore, a source for contamination of fresh produce. We tested this by comparing irrigation water samples taken from five different greenhouses in Belgium. The water samples were inoculated with four zoonotic strains, two Salmonella and two E. coli O157:H7 strains, and pathogen survival and growth in the water were monitored up till 14 days. The influence of water temperature and chemical water quality was evaluated, and the survival tests were also performed in water samples from which the resident aquatic microbiota had previously been eliminated by filter sterilization. The pathogen’s survival differed greatly in the different irrigation waters. Three water samples contained nutrients to support important growth of the pathogens, and another enabled weaker growth. However, for all, growth was only observed in the samples that did not contain the resident aquatic microbiota. In the original waters with their specific water biota, pathogen levels declined. The same survival tendencies existed in water of 4 °C and 20 °C, although always more expressed at 20 °C. Low water temperatures resulted in longer pathogen survival. Remarkably, the survival capacity of two E. coli 0157:H7 strains differed, while Salmonella Thompson and Salmonella Typhimurium behaved similarly. The pathogens were also transferred to detached lettuce leaves, while suspended in two of the water samples or in a buffer. The effect of the water sample on the pathogen’s fitness was also reproduced on the leaves when stored at 100% relative humidity. Inoculation of the suspension in buffer or in one of the water samples enabled epiphytic growth and survival, while the pathogen level in the other water sample decreased once loaded on the leaves. Our results show that irrigation waters from different origin may have a different capacity to transmit enteric pathogens and

  7. Importance of Soil Amendments: Survival of Bacterial Pathogens in Manure and Compost Used as Organic Fertilizers.

    Science.gov (United States)

    Sharma, Manan; Reynnells, Russell

    2016-08-01

    Biological soil amendments (BSAs) such as manure and compost are frequently used as organic fertilizers to improve the physical and chemical properties of soils. However, BSAs have been known to be a reservoir for enteric bacterial pathogens such as enterohemorrhagic Escherichia coli (EHEC), Salmonella spp., and Listeria spp. There are numerous mechanisms by which manure may transfer pathogens to growing fruits and vegetables, and several outbreaks of infections have been linked to manure-related contamination of leafy greens. In the United States several commodity-specific guidelines and current and proposed federal rules exist to provide guidance on the application of BSAs as fertilizers to soils, some of which require an interval between the application of manure to soils and the harvest of fruits and vegetables. This review examines the survival, persistence, and regrowth/resuscitation of bacterial pathogens in manure, biosolids, and composts. Moisture, along with climate and the physicochemical properties of soil, manure, or compost, plays a significant role in the ability of pathogens to persist and resuscitate in amended soils. Adaptation of enteric bacterial pathogens to the nonhost environment of soils may also extend their persistence in manure- or compost-amended soils. The presence of antibiotic-resistance genes in soils may also be increased by manure application. Overall, BSAs applied as fertilizers to soils can support the survival and regrowth of pathogens. BSAs should be handled and applied in a manner that reduces the prevalence of pathogens in soils and the likelihood of transfer of food-borne pathogens to fruits and vegetables. This review will focus on two BSAs-raw manure and composted manure (and other feedstocks)-and predominantly on the survival of enteric bacterial pathogens in BSAs as applied to soils as organic fertilizers.

  8. Protozoan Cysts Act as a Survival Niche and Protective Shelter for Foodborne Pathogenic Bacteria

    Science.gov (United States)

    Lambrecht, Ellen; Baré, Julie; Chavatte, Natascha; Bert, Wim; Sabbe, Koen

    2015-01-01

    The production of cysts, an integral part of the life cycle of many free-living protozoa, allows these organisms to survive adverse environmental conditions. Given the prevalence of free-living protozoa in food-related environments, it is hypothesized that these organisms play an important yet currently underinvestigated role in the epidemiology of foodborne pathogenic bacteria. Intracystic bacterial survival is highly relevant, as this would allow bacteria to survive the stringent cleaning and disinfection measures applied in food-related environments. The present study shows that strains of widespread and important foodborne bacteria (Salmonella enterica, Escherichia coli, Yersinia enterocolitica, and Listeria monocytogenes) survive inside cysts of the ubiquitous amoeba Acanthamoeba castellanii, even when exposed to either antibiotic treatment (100 μg/ml gentamicin) or highly acidic conditions (pH 0.2) and resume active growth in broth media following excystment. Strain- and species-specific differences in survival periods were observed, with Salmonella enterica surviving up to 3 weeks inside amoebal cysts. Up to 53% of the cysts were infected with pathogenic bacteria, which were located in the cyst cytosol. Our study suggests that the role of free-living protozoa and especially their cysts in the persistence and epidemiology of foodborne bacterial pathogens in food-related environments may be much more important than hitherto assumed. PMID:26070667

  9. Targeted Disruption of Melanin Biosynthesis Genes in the Human Pathogenic Fungus Lomentospora prolificans and Its Consequences for Pathogen Survival

    Directory of Open Access Journals (Sweden)

    Ayat Al-Laaeiby

    2016-03-01

    Full Text Available The dematiaceous (melanised fungus Lomentospora (Scedosporium prolificans is a life-threatening opportunistic pathogen of immunocompromised humans, resistant to anti-fungal drugs. Melanin has been shown to protect human pathogenic fungi against antifungal drugs, oxidative killing and environmental stresses. To determine the protective role of melanin in L. prolificans to oxidative killing (H2O2, UV radiation and the polyene anti-fungal drug amphotericin B, targeted gene disruption was used to generate mutants of the pathogen lacking the dihydroxynaphthalene (DHN-melanin biosynthetic enzymes polyketide synthase (PKS1, tetrahydroxynapthalene reductase (4HNR and scytalone dehydratase (SCD1. Infectious propagules (spores of the wild-type strain 3.1 were black/brown, whereas spores of the PKS-deficient mutant ΔLppks1::hph were white. Complementation of the albino mutant ΔLppks1::hph restored the black-brown spore pigmentation, while the 4HNR-deficient mutant ΔLp4hnr::hph and SCD-deficient mutant ΔLpscd1::hph both produced orange-yellow spores. The mutants ΔLppks1::hph and ΔLp4hnr::hph showed significant reductions in spore survival following H2O2 treatment, while spores of ΔLpscd1::hph and the ΔLppks1::hph complemented strain ΔLppks1::hph:PKS showed spore survivals similar to strain 3.1. Spores of the mutants ΔLp4hnr::hph and ΔLpscd1::hph and complemented strain ΔLppks1::hph:PKS showed spore survivals similar to 3.1 following exposure to UV radiation, but survival of ΔLppks1::hph spores was significantly reduced compared to the wild-type strain. Strain 3.1 and mutants ΔLp4hnr::hph and ΔLppks1::hph:PKS were resistant to amphotericin B while, paradoxically, the PKS1- and SCD1-deficient mutants showed significant increases in growth in the presence of the antifungal drug. Taken together, these results show that while melanin plays a protective role in the survival of the pathogen to oxidative killing and UV radiation, melanin does not

  10. Targeted Disruption of Melanin Biosynthesis Genes in the Human Pathogenic Fungus Lomentospora prolificans and Its Consequences for Pathogen Survival.

    Science.gov (United States)

    Al-Laaeiby, Ayat; Kershaw, Michael J; Penn, Tina J; Thornton, Christopher R

    2016-03-24

    The dematiaceous (melanised) fungus Lomentospora (Scedosporium) prolificans is a life-threatening opportunistic pathogen of immunocompromised humans, resistant to anti-fungal drugs. Melanin has been shown to protect human pathogenic fungi against antifungal drugs, oxidative killing and environmental stresses. To determine the protective role of melanin in L. prolificans to oxidative killing (H₂O₂), UV radiation and the polyene anti-fungal drug amphotericin B, targeted gene disruption was used to generate mutants of the pathogen lacking the dihydroxynaphthalene (DHN)-melanin biosynthetic enzymes polyketide synthase (PKS1), tetrahydroxynapthalene reductase (4HNR) and scytalone dehydratase (SCD1). Infectious propagules (spores) of the wild-type strain 3.1 were black/brown, whereas spores of the PKS-deficient mutant ΔLppks1::hph were white. Complementation of the albino mutant ΔLppks1::hph restored the black-brown spore pigmentation, while the 4HNR-deficient mutant ΔLp4hnr::hph and SCD-deficient mutant ΔLpscd1::hph both produced orange-yellow spores. The mutants ΔLppks1::hph and ΔLp4hnr::hph showed significant reductions in spore survival following H₂O₂ treatment, while spores of ΔLpscd1::hph and the ΔLppks1::hph complemented strain ΔLppks1::hph:PKS showed spore survivals similar to strain 3.1. Spores of the mutants ΔLp4hnr::hph and ΔLpscd1::hph and complemented strain ΔLppks1::hph:PKS showed spore survivals similar to 3.1 following exposure to UV radiation, but survival of ΔLppks1::hph spores was significantly reduced compared to the wild-type strain. Strain 3.1 and mutants ΔLp4hnr::hph and ΔLppks1::hph:PKS were resistant to amphotericin B while, paradoxically, the PKS1- and SCD1-deficient mutants showed significant increases in growth in the presence of the antifungal drug. Taken together, these results show that while melanin plays a protective role in the survival of the pathogen to oxidative killing and UV radiation, melanin does not

  11. Incidence of and survival after subsequent cancers in carriers of pathogenic MMR variants with previous cancer

    DEFF Research Database (Denmark)

    Møller, Pål; Seppälä, Toni; Bernstein, Inge

    2017-01-01

    age 40 to age 70 years were 73% for pathogenic MLH1 (path_MLH1), 76% for path_MSH2 carriers and 52% for path_MSH6 carriers, and for colorectal cancer (CRC) the cumulative incidences were 46%, 48% and 23%, respectively. Crude survival after any subsequent cancer was 82% (95% CI 76% to 87%) and 10-year...

  12. Assessment of pathogen survival potential during managed aquifer recharge with diffusion chambers.

    Science.gov (United States)

    Sidhu, J P S; Toze, S

    2012-09-01

    To evaluate the efficacy of using in situ diffusion chambers for pathogen decay studies in the aquifer. A comparative microbial inactivation study was carried out in groundwater by seeding selected pathogens and indicators in laboratory microcosms and Teflon diffusion chambers (in situ) fitted with 0.010- and 0.025-μm pore-size membranes. The results have shown that there is a difference in the decay rates obtained from the laboratory microcosms and in situ diffusion chambers for several pathogens. The results suggest that the use of laboratory microcosms to determine pathogen decay during the Managed Aquifer Recharge (MAR) may lead to underestimation of decay of adenovirus and Cryptosporidium and subsequent inaccurate assessment of the required residence time in the aquifer for pathogens to be removed from the recharged water. The decay rate of two indicator bacteria, Salmonella enterica and adenovirus, was found to be significantly slower (t-test, P aquifers. Reliable assessment of potential public health risks from the presence of pathogens in groundwater is essential for proper management of the MAR schemes. The results of this study suggest that in situ assessment of pathogen survival potential in diffusion chambers provided more reliable data for pathogen risk assessment and subsequent risk mitigation plans for MAR schemes. © 2012 The Authors Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

  13. Settling and survival profile of enteric pathogens in the swine effluent for water reuse purpose.

    Science.gov (United States)

    Fongaro, G; Kunz, A; Magri, M E; Schissi, C D; Viancelli, A; Philippi, L S; Barardi, C R M

    2016-11-01

    The present study evaluated the pathogens persistence and settling profile in swine effluent. We determined the enteric pathogens settling characteristics, their survival and inactivation profile in swine effluent (for water reuse purpose) and in sludge (generated after aerobic treatment - during secondary settling process). The study was performed in laboratorial-scale and in full-scale (manure treatment plant). Enteric viruses and enteric bacteria were used as biomarkers. Results showed that these enteric pathogens were significantly reduced from swine effluent during secondary settling process, and enteric viruses removal was correlated with the suspended solids decantation. The design of secondary settlers can be adapted to improve pathogens removal, by diminishing the solids loading rate per area and time, ending in higher hydraulic retention times. Copyright © 2016 Elsevier GmbH. All rights reserved.

  14. Using cure models for analyzing the influence of pathogens on salmon survival

    Science.gov (United States)

    Ray, Adam R; Perry, Russell W.; Som, Nicholas A.; Bartholomew, Jerri L

    2014-01-01

    Parasites and pathogens influence the size and stability of wildlife populations, yet many population models ignore the population-level effects of pathogens. Standard survival analysis methods (e.g., accelerated failure time models) are used to assess how survival rates are influenced by disease. However, they assume that each individual is equally susceptible and will eventually experience the event of interest; this assumption is not typically satisfied with regard to pathogens of wildlife populations. In contrast, mixture cure models, which comprise logistic regression and survival analysis components, allow for different covariates to be entered into each part of the model and provide better predictions of survival when a fraction of the population is expected to survive a disease outbreak. We fitted mixture cure models to the host–pathogen dynamics of Chinook Salmon Oncorhynchus tshawytscha and Coho Salmon O. kisutch and the myxozoan parasite Ceratomyxa shasta. Total parasite concentration, water temperature, and discharge were used as covariates to predict the observed parasite-induced mortality in juvenile salmonids collected as part of a long-term monitoring program in the Klamath River, California. The mixture cure models predicted the observed total mortality well, but some of the variability in observed mortality rates was not captured by the models. Parasite concentration and water temperature were positively associated with total mortality and the mortality rate of both Chinook Salmon and Coho Salmon. Discharge was positively associated with total mortality for both species but only affected the mortality rate for Coho Salmon. The mixture cure models provide insights into how daily survival rates change over time in Chinook Salmon and Coho Salmon after they become infected with C. shasta.

  15. Survival of enteric pathogens in common beverages: an in vitro study.

    Science.gov (United States)

    Sheth, N K; Wisniewski, T R; Franson, T R

    1988-06-01

    This in vitro study was undertaken to determine the potential for survival of enteric pathogens in common drinking beverages. Three carbonated soft drinks, two alcoholic beverages, skim milk, and water were inoculated with Salmonella, Shigella, and enterotoxigenic Escherichia coli, and quantitative counts were performed over 2 days. Our studies showed poorest survival of all three organisms in wine, and greatest growth in milk and water. Beer and cola allowed survival of small numbers of Salmonella and E. coli at 48 h, whereas sour mix and diet cola were sterile by 48 h. Survival features may correlate with pH of the beverages. These observations may be useful in guiding travellers for appropriate beverage consumption while visiting areas endemic for "traveller's diarrhea."

  16. Survival of viral pathogens in animal feed ingredients under transboundary shipping models

    Science.gov (United States)

    Bauermann, Fernando V.; Niederwerder, Megan C.; Singrey, Aaron; Clement, Travis; de Lima, Marcelo; Long, Craig; Patterson, Gilbert; Sheahan, Maureen A.; Stoian, Ana M. M.; Petrovan, Vlad; Jones, Cassandra K.; De Jong, Jon; Ji, Ju; Spronk, Gordon D.; Minion, Luke; Christopher-Hennings, Jane; Zimmerman, Jeff J.; Rowland, Raymond R. R.; Nelson, Eric; Sundberg, Paul; Diel, Diego G.

    2018-01-01

    The goal of this study was to evaluate survival of important viral pathogens of livestock in animal feed ingredients imported daily into the United States under simulated transboundary conditions. Eleven viruses were selected based on global significance and impact to the livestock industry, including Foot and Mouth Disease Virus (FMDV), Classical Swine Fever Virus (CSFV), African Swine Fever Virus (ASFV), Influenza A Virus of Swine (IAV-S), Pseudorabies virus (PRV), Nipah Virus (NiV), Porcine Reproductive and Respiratory Syndrome Virus (PRRSV), Swine Vesicular Disease Virus (SVDV), Vesicular Stomatitis Virus (VSV), Porcine Circovirus Type 2 (PCV2) and Vesicular Exanthema of Swine Virus (VESV). Surrogate viruses with similar genetic and physical properties were used for 6 viruses. Surrogates belonged to the same virus families as target pathogens, and included Senecavirus A (SVA) for FMDV, Bovine Viral Diarrhea Virus (BVDV) for CSFV, Bovine Herpesvirus Type 1 (BHV-1) for PRV, Canine Distemper Virus (CDV) for NiV, Porcine Sapelovirus (PSV) for SVDV and Feline Calicivirus (FCV) for VESV. For the remaining target viruses, actual pathogens were used. Virus survival was evaluated using Trans-Pacific or Trans-Atlantic transboundary models involving representative feed ingredients, transport times and environmental conditions, with samples tested by PCR, VI and/or swine bioassay. SVA (representing FMDV), FCV (representing VESV), BHV-1 (representing PRV), PRRSV, PSV (representing SVDV), ASFV and PCV2 maintained infectivity during transport, while BVDV (representing CSFV), VSV, CDV (representing NiV) and IAV-S did not. Notably, more viruses survived in conventional soybean meal, lysine hydrochloride, choline chloride, vitamin D and pork sausage casings. These results support published data on transboundary risk of PEDV in feed, demonstrate survival of certain viruses in specific feed ingredients (“high-risk combinations”) under conditions simulating transport between

  17. Survival of pathogenic and lactobacilli species of fermented olives during simulated human digestion.

    Science.gov (United States)

    Arroyo-López, Francisco N; Blanquet-Diot, Stéphanie; Denis, Sylvain; Thévenot, Jonathan; Chalancon, Sandrine; Alric, Monique; Rodríguez-Gómez, Francisco; Romero-Gil, Verónica; Jiménez-Díaz, Rufino; Garrido-Fernández, Antonio

    2014-01-01

    The present survey uses a dynamic gastric and small intestinal model to assess the survival of one pathogenic (Escherichia coli O157:H7 EDL 933) and three lactobacilli bacteria with probiotic potential (Lactobacillus rhamnosus GG, L. pentosus TOMC-LAB2, and L. pentosus TOMC-LAB4) during their passage through the human gastrointestinal tract using fermented olives as the food matrix. The data showed that the survival of the E. coli strain in the stomach and duodenum was very low, while its transit through the distal parts (jejunum and ileum) resulted in an increase in the pathogen population. The production of Shiga toxins by this enterohemorrhagic microorganism in the ileal effluents of the in vitro system was too low to be detected by ELISA assays. On the contrary, the three lactobacilli species assayed showed a considerable resistance to the gastric digestion, but not to the intestinal one, which affected their survival, and was especially evident in the case of both L. pentosus strains. In spite of this, high population levels for all assayed microorganisms were recovered at the end of the gastrointestinal passage. The results obtained in the present study show the potential use of table olives as a vehicle of beneficial microorganisms to the human body, as well as the need for good hygienic practices on the part of olive manufacturers in order to avoid the possibility of contamination by food-borne pathogens.

  18. Survival of pathogenic and lactobacilli species of fermented olives during simulated human digestion

    Directory of Open Access Journals (Sweden)

    Francisco Noé eArroyo López

    2014-10-01

    Full Text Available The present survey uses a dynamic gastric and small intestinal model to assess the survival of one pathogenic (Escherichia coli O157:H7 EDL 933 and three lactobacilli bacteria with probiotic potential (Lactobacillus rhamnosus GG, Lactobacillus pentosus TOMC-LAB2 and Lactobacillus pentosus TOMC-LAB4 during their passage through the human gastrointestinal tract using fermented olives as the food matrix. The data showed that the survival of the E. coli strain in the stomach and duodenum was very low, while its transit through the distal parts (jejunum and ileum resulted in an increase in the pathogen population. The production of Shiga toxins by this enterohemorrhagic microorganism in the ileal effluents of the in vitro system was too low to be detected by ELISA assays. On the contrary, the three lactobacilli species assayed showed a considerable resistance to the gastric digestion, but not to the intestinal one, which affected their survival, and was especially evident in the case of both L. pentosus strains. In spite of this, high population levels for all assayed microorganisms were recovered at the end of the gastrointestinal passage. The results obtained in the present study show the potential use of table olives as a vehicle of beneficial microorganisms to the human body, as well as the need for good hygienic practices on the part of olive manufacturers in order to avoid the possibility of contamination by food-borne pathogens.

  19. Anti-pathogen protection versus survival costs mediated by an ectosymbiont in an ant host.

    Science.gov (United States)

    Konrad, Matthias; Grasse, Anna V; Tragust, Simon; Cremer, Sylvia

    2015-01-22

    The fitness effects of symbionts on their hosts can be context-dependent, with usually benign symbionts causing detrimental effects when their hosts are stressed, or typically parasitic symbionts providing protection towards their hosts (e.g. against pathogen infection). Here, we studied the novel association between the invasive garden ant Lasius neglectus and its fungal ectosymbiont Laboulbenia formicarum for potential costs and benefits. We tested ants with different Laboulbenia levels for their survival and immunity under resource limitation and exposure to the obligate killing entomopathogen Metarhizium brunneum. While survival of L. neglectus workers under starvation was significantly decreased with increasing Laboulbenia levels, host survival under Metarhizium exposure increased with higher levels of the ectosymbiont, suggesting a symbiont-mediated anti-pathogen protection, which seems to be driven mechanistically by both improved sanitary behaviours and an upregulated immune system. Ants with high Laboulbenia levels showed significantly longer self-grooming and elevated expression of immune genes relevant for wound repair and antifungal responses (β-1,3-glucan binding protein, Prophenoloxidase), compared with ants carrying low Laboulbenia levels. This suggests that the ectosymbiont Laboulbenia formicarum weakens its ant host by either direct resource exploitation or the costs of an upregulated behavioural and immunological response, which, however, provides a prophylactic protection upon later exposure to pathogens. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  20. Anti-pathogen protection versus survival costs mediated by an ectosymbiont in an ant host

    Science.gov (United States)

    Konrad, Matthias; Grasse, Anna V.; Tragust, Simon; Cremer, Sylvia

    2015-01-01

    The fitness effects of symbionts on their hosts can be context-dependent, with usually benign symbionts causing detrimental effects when their hosts are stressed, or typically parasitic symbionts providing protection towards their hosts (e.g. against pathogen infection). Here, we studied the novel association between the invasive garden ant Lasius neglectus and its fungal ectosymbiont Laboulbenia formicarum for potential costs and benefits. We tested ants with different Laboulbenia levels for their survival and immunity under resource limitation and exposure to the obligate killing entomopathogen Metarhizium brunneum. While survival of L. neglectus workers under starvation was significantly decreased with increasing Laboulbenia levels, host survival under Metarhizium exposure increased with higher levels of the ectosymbiont, suggesting a symbiont-mediated anti-pathogen protection, which seems to be driven mechanistically by both improved sanitary behaviours and an upregulated immune system. Ants with high Laboulbenia levels showed significantly longer self-grooming and elevated expression of immune genes relevant for wound repair and antifungal responses (β-1,3-glucan binding protein, Prophenoloxidase), compared with ants carrying low Laboulbenia levels. This suggests that the ectosymbiont Laboulbenia formicarum weakens its ant host by either direct resource exploitation or the costs of an upregulated behavioural and immunological response, which, however, provides a prophylactic protection upon later exposure to pathogens. PMID:25473011

  1. Relationship of external fish condition to pathogen prevalence and out-migration survival in juvenile steelhead

    Science.gov (United States)

    Hostetter, N.J.; Evans, A.F.; Roby, D.D.; Collis, K.; Hawbecker, M.; Sandford, B.P.; Thompson, D.E.; Loge, F.J.

    2011-01-01

    Understanding how the external condition of juvenile salmonids is associated with internal measures of health and subsequent out-migration survival can be valuable for population monitoring programs. This study investigated the use of a rapid, nonlethal, external examination to assess the condition of run-of-the-river juvenile steelhead Oncorhynchus mykiss migrating from the Snake River to the Pacific Ocean. We compared the external condition (e.g., body injuries, descaling, external signs of disease, fin damage, and ectoparasite infestations) with (1) the internal condition of a steelhead as measured by the presence of selected pathogens detected by histopathology and polymerase chain reaction analysis and (2) out-migration survival through the Snake and Columbia rivers as determined by passive integrated transponder (PIT) tag technology. The results from steelhead captured and euthanized (n = 222) at Lower Monumental Dam on the lower Snake River in 2008 indicated that external condition was significantly correlated with selected measures of internal condition. The odds of testing positive for a pathogen were 39.2, 24.3, and 5.6 times greater for steelhead with severe or moderate external signs of disease or more than 20% descaling, respectively. Capture-recapture models of 22,451 PIT-tagged steelhead released at Lower Monumental Dam in 2007-2009 indicated that external condition was significantly correlated with juvenile survival. The odds of outmigration survival for steelhead with moderate or severe external signs of disease, more than 20% descaling, or severe fin damage were 5.7, 4.9, 1.6, and 1.3 times lower, respectively, than those for steelhead without these external conditions. This study effectively demonstrated that specific measures of external condition were associated with both the internal condition and out-migration survival of juvenile steelhead. ?? American Fisheries Society 2011.

  2. Effect of Temperature and Nutrient Concentration on Survival of Foodborne Pathogens in Deciduous Fruit Processing Environments for Effective Hygiene Management.

    Science.gov (United States)

    Duvenage, Stacey; Korsten, Lise

    2016-11-01

    Temperature and good sanitation practices are important factors for controlling growth of microorganisms. Fresh produce is stored at various temperatures to ensure quality and to prolong shelf life. When foodborne pathogens survive and grow on fresh produce at storage temperatures, then additional control strategies are needed to inactivate these pathogens. The aim of this study was to determine how temperatures associated with deciduous fruit processing and storage facilities (0.5, 4, and 21°C) affect the growth and/or survival of Escherichia coli O157:H7, Listeria monocytogenes , Salmonella enterica subsp. enterica serovar Typhimurium, and Staphylococcus aureus under different nutrient conditions (nutrient rich and nutrient poor) and on simulated contact surfaces (vinyl coupons). Information on the growth and survival of foodborne pathogens at specific deciduous fruit processing and storage temperatures (0.5°C) is not available. All pathogens except E. coli O157:H7 were able to survive on vinyl coupons at all temperatures. L. monocytogenes proliferated under both nutrient conditions independent of temperature. S. aureus was the pathogen least affected by nutrient conditions. The survival of foodborne pathogens on the vinyl coupons, a model system for studying surfaces in fruit preparation and storage environments, indicates the potential for cross-contamination of deciduous fruit products under poor sanitation conditions. Foodborne pathogens that can proliferate and survive at various temperatures under different nutrient conditions could lead to fruit cross-contamination. Temperature mismanagement, which could allow pathogen proliferation in contaminated fruit packing houses and storage environments, is a concern. Therefore, proper hygiene and sanitation practices, removal of possible contaminants, and proper food safety management systems are needed to ensure food safety.

  3. Probiotics improve survival of septic rats by suppressing conditioned pathogens in ascites

    Science.gov (United States)

    Liu, Da-Quan; Gao, Qiao-Ying; Liu, Hong-Bin; Li, Dong-Hua; Wu, Shang-Wei

    2013-01-01

    AIM: To investigate the benefits of probiotics treatment in septic rats. METHODS: The septic rats were induced by cecal ligation and puncture. The animals of control, septic model and probiotics treated groups were treated with vehicle and mixed probiotics, respectively. The mixture of probiotics included Bifidobacterium longum, Lactobacillus bulgaricus and Streptococcus thermophilus. We observed the survival of septic rats using different amounts of mixed probiotics. We also detected the bacterial population in ascites and blood of experimental sepsis using cultivation and real-time polymerase chain reaction. The severity of mucosal inflammation in colonic tissues was determined. RESULTS: Probiotics treatment improved survival of the rats significantly and this effect was dose dependent. The survival rate was 30% for vehicle-treated septic model group. However, 1 and 1/4 doses of probiotics treatment increased survival rate significantly compared with septic model group (80% and 55% vs 30%, P probiotics treated group compared with septic model group (5.20 ± 0.57 vs 9.81 ± 0.67, P probiotics treated group compared with septic model group (33.3% vs 100.0%, P probiotics treated group were decreased significantly compared with that of septic model group (3.93 ± 0.73 vs 8.80 ± 0.83, P probiotics treatment, there was a decrease in the scores of inflammatory cell infiltration into the intestinal mucosa in septic animals (1.50 ± 0.25 vs 2.88 ± 0.14, P Probiotics improve survival of septic rats by suppressing these conditioned pathogens. PMID:23840152

  4. Spinal muscular atrophy pathogenic mutations impair the axonogenic properties of axonal-survival of motor neuron.

    Science.gov (United States)

    Locatelli, Denise; d'Errico, Paolo; Capra, Silvia; Finardi, Adele; Colciaghi, Francesca; Setola, Veronica; Terao, Mineko; Garattini, Enrico; Battaglia, Giorgio

    2012-05-01

    The axonal survival of motor neuron (a-SMN) protein is a truncated isoform of SMN1, the spinal muscular atrophy (SMA) disease gene. a-SMN is selectively localized in axons and endowed with remarkable axonogenic properties. At present, the role of a-SMN in SMA is unknown. As a first step to verify a link between a-SMN and SMA, we investigated by means of over-expression experiments in neuroblastoma-spinal cord hybrid cell line (NSC34) whether SMA pathogenic mutations located in the N-terminal part of the protein affected a-SMN function. We demonstrated here that either SMN1 missense mutations or small intragenic re-arrangements located in the Tudor domain consistently altered the a-SMN capability of inducing axonal elongation in vitro. Mutated human a-SMN proteins determined in almost all NSC34 motor neurons the growth of short axons with prominent morphologic abnormalities. Our data indicate that the Tudor domain is critical in dictating a-SMN function possibly because it is an association domain for proteins involved in axon growth. They also indicate that Tudor domain mutations are functionally relevant not only for FL-SMN but also for a-SMN, raising the possibility that also a-SMN loss of function may contribute to the pathogenic steps leading to SMA. © 2012 The Authors. Journal of Neurochemistry © 2012 International Society for Neurochemistry.

  5. Survival of Spoilage and Pathogenic Microorganisms on Cardboard and Plastic Packaging Materials

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    Lorenzo Siroli

    2017-12-01

    Full Text Available The aim of this work was to study the interaction of corrugated and plastic materials with pathogenic and spoiling microorganisms frequently associated to fresh produce. The effect of the two packaging materials on the survival during the storage of microorganisms belonging to the species Escherichia coli, Listeria monocytogenes, Salmonella enteritidis, Saccharomyces cerevisiae, Lactobacillus plantarum, Pseudomonas fluorescens, and Aspergillus flavus was studied through traditional plate counting and scanning electron microscopy (SEM. The results obtained showed that cardboard materials, if correctly stored, reduced the potential of packaging to cross-contaminate food due to a faster viability loss by spoilage and pathogenic microorganisms compared to the plastic ones. In fact, the cell loads of the pathogenic species considered decreased over time independently on the inoculation level and packaging material used. However, the superficial viability losses were significantly faster in cardboard compared to plastic materials. The same behavior was observed for the spoilage microorganisms considered. The SEM microphotographs indicate that the reduction of superficial contamination on cardboard surfaces was due to the entrapping of the microbial cells within the fibers and the pores of this material. In addition, SEM data showed that the entrapped cells were subjected to more or less rapid lyses, depending on the species, due to the absence of water and nutrients, with the exception of molds. The latter spoilers were able to proliferate inside the cardboard fibers only when the absorption of water was not prevented during the storage. In conclusion, the findings of this work showed the reduction of cross-contamination potential of corrugated compared to plastic packaging materials used in fruit and vegetable sector. However, the findings outlined the importance of hygiene and low humidity during cardboard storage to prevent the mold growth on

  6. Survival after pathogen exposure in group-living insects: don't forget the stress of social isolation!

    Science.gov (United States)

    Kohlmeier, P; Holländer, K; Meunier, J

    2016-09-01

    A major cost of group-living is its inherent risk of pathogen infection. To limit this risk, many group-living animals have developed the capability to prophylactically boost their immune system in the presence of group members and/or to mount collective defences against pathogens. These two phenomena, called density-dependent prophylaxis and social immunity, respectively, are often used to explain why, in group-living species, individuals survive better in groups than in isolation. However, this survival difference may also reflect an alternative and often overlooked process: a cost of social isolation on individuals' capability to fight against infections. Here, we disentangled the effects of density-dependent prophylaxis, social immunity and stress of social isolation on the survival after pathogen exposure in group-living adults of the European earwig Forficula auricularia. By manipulating the presence of group members both before and after pathogen exposure, we demonstrated that the cost of being isolated after infection, but not the benefits of social immunity or density-dependent prophylaxis, explained the survival of females. Specifically, females kept constantly in groups or constantly isolated had higher survival rates than females that were first in groups and then isolated after infection. Our results also showed that this cost of social isolation was absent in males and that social isolation did not reduce the survival of noninfected individuals. Overall, this study gives a new perspective on the role of pathogens in social evolution, as it suggests that an apparently nonadaptive, personal immune process may promote the maintenance of group-living under pathogenic environments. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

  7. Meta-regression analysis of commensal and pathogenic Escherichia coli survival in soil and water.

    Science.gov (United States)

    Franz, Eelco; Schijven, Jack; de Roda Husman, Ana Maria; Blaak, Hetty

    2014-06-17

    The extent to which pathogenic and commensal E. coli (respectively PEC and CEC) can survive, and which factors predominantly determine the rate of decline, are crucial issues from a public health point of view. The goal of this study was to provide a quantitative summary of the variability in E. coli survival in soil and water over a broad range of individual studies and to identify the most important sources of variability. To that end, a meta-regression analysis on available literature data was conducted. The considerable variation in reported decline rates indicated that the persistence of E. coli is not easily predictable. The meta-analysis demonstrated that for soil and water, the type of experiment (laboratory or field), the matrix subtype (type of water and soil), and temperature were the main factors included in the regression analysis. A higher average decline rate in soil of PEC compared with CEC was observed. The regression models explained at best 57% of the variation in decline rate in soil and 41% of the variation in decline rate in water. This indicates that additional factors, not included in the current meta-regression analysis, are of importance but rarely reported. More complete reporting of experimental conditions may allow future inference on the global effects of these variables on the decline rate of E. coli.

  8. Survival of Potentially Pathogenic Human-Associated Bacteria in the Rhizosphere of Hydroponically Grown Wheat

    Science.gov (United States)

    Morales, Anabelle; Garland, Jay L.; Lim, Daniel V.

    1996-01-01

    Plants may serve as reservoirs for human-associated bacteria (H-AB) in long-term space missions containing bioregenerative life support systems. The current study examined the abilities of five human-associated potential pathogens, Pseudomonas aeruginosa, Pseudomonas cepacia, Staphylococcus aureus, Streptococcus pyogenes, and Escherichia coli, to colonize and grow in the rhizosphere of hydroponically grown wheat, a candidate crop for life support. All of these bacteria have been recovered from past NASA missions and present potential problems for future missions. The abilities of these organisms to adhere to the roots of axenic five-day-old wheat (Triticum aestivum L. cv. Yecora rojo) were evaluated by enumeration of the attached organisms after a one hour incubation of roots in a suspension (approximately 10(exp 8 cu/ml)) of the H-AB. Results showed that a greater percentage of P. aeruginosa cells adhered to the wheat roots than the other four H-AB. Similarly incubated seedlings were also grown under attempted axenic conditions for seven days to examine the potential of each organism to proliferate in the rhizosphere (root colonization capacity). P. cepacia and P. aeruginosa showed considerable growth. E. coli and S. aureus showed no significant growth, and S. pyogenes died off in the wheat rhizosphere. Studies examining the effects of competition on the survival of these microorganisms indicated that P. aeruginosa was the only organism that survived in the rhizosphere of hydroponically grown wheat in the presence of different levels of microbial competition.

  9. Anaerobic digestion in mesophilic and room temperature conditions: Digestion performance and soil-borne pathogen survival.

    Science.gov (United States)

    Chen, Le; Jian, Shanshan; Bi, Jinhua; Li, Yunlong; Chang, Zhizhou; He, Jian; Ye, Xiaomei

    2016-05-01

    Tomato plant waste (TPW) was used as the feedstock of a batch anaerobic reactor to evaluate the effect of anaerobic digestion on Ralstonia solanacearum and Phytophthora capsici survival. Batch experiments were carried out for TS (total solid) concentrations of 2%, 4% and 6% respectively, at mesophilic (37±1°C) and room (20-25°C) temperatures. Results showed that higher digestion performance was achieved under mesophilic digestion temperature and lower TS concentration conditions. The biogas production ranged from 71 to 416L/kg VS (volatile solids). The inactivation of anaerobic digestion tended to increase as digestion performance improved. The maximum log copies reduction of R. solanacearum and P. capsici detected by quantitative PCR (polymerase chain reaction) were 3.80 and 4.08 respectively in reactors with 4% TS concentration at mesophilic temperatures. However, both in mesophilic and room temperature conditions, the lowest reduction of R. solanacearum was found in the reactors with 6% TS concentration, which possessed the highest VFA (volatile fatty acid) concentration. These findings indicated that simple accumulation of VFAs failed to restrain R. solanacearum effectively, although the VFAs were considered poisonous. P. capsici was nearly completely dead under all conditions. Based on the digestion performance and the pathogen survival rate, a model was established to evaluate the digestate biosafety. Copyright © 2015. Published by Elsevier B.V.

  10. Epigenetic silencing of host cell defense genes enhances intracellular survival of the rickettsial pathogen Anaplasma phagocytophilum.

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    Jose C Garcia-Garcia

    2009-06-01

    Full Text Available Intracellular bacteria have evolved mechanisms that promote survival within hostile host environments, often resulting in functional dysregulation and disease. Using the Anaplasma phagocytophilum-infected granulocyte model, we establish a link between host chromatin modifications, defense gene transcription and intracellular bacterial infection. Infection of THP-1 cells with A. phagocytophilum led to silencing of host defense gene expression. Histone deacetylase 1 (HDAC1 expression, activity and binding to the defense gene promoters significantly increased during infection, which resulted in decreased histone H3 acetylation in infected cells. HDAC1 overexpression enhanced infection, whereas pharmacologic and siRNA HDAC1 inhibition significantly decreased bacterial load. HDAC2 does not seem to be involved, since HDAC2 silencing by siRNA had no effect on A. phagocytophilum intracellular propagation. These data indicate that HDAC up-regulation and epigenetic silencing of host cell defense genes is required for A. phagocytophilum infection. Bacterial epigenetic regulation of host cell gene transcription could be a general mechanism that enhances intracellular pathogen survival while altering cell function and promoting disease.

  11. Factors Affecting Pathogen Survival in Finished Dairy Compost with Different Particle Sizes Under Greenhouse Conditions.

    Science.gov (United States)

    Diao, Junshu; Chen, Zhao; Gong, Chao; Jiang, Xiuping

    2015-09-01

    This study investigated the survival of Escherichia coli O157:H7 and Salmonella Typhimurium in finished dairy compost with different particle sizes during storage as affected by moisture content and temperature under greenhouse conditions. The mixture of E. coli O157:H7 and S. Typhimurium strains was inoculated into the finished composts with moisture contents of 20, 30, and 40%, separately. The finished compost samples were then sieved into 3 different particle sizes (>1000, 500-1000, and 500 μm) and stored under greenhouse conditions. For compost samples with moisture contents of 20 and 30%, the average Salmonella reductions in compost samples with particle sizes of >1000, 500-1000, and 500 μm were 2.15, 2.27, and 2.47 log colony-forming units (CFU) g(-1) within 5 days of storage in summer, respectively, as compared with 1.60, 2.03, and 2.26 log CFU g(-1) in late fall, respectively, and 2.61, 3.33, and 3.67 log CFU g(-1) in winter, respectively. The average E. coli O157:H7 reductions in compost samples with particle sizes of >1000, 500-1000, and 500 μm were 1.98, 2.30, and 2.54 log CFU g(-1) within 5 days of storage in summer, respectively, as compared with 1.70, 2.56, and 2.90 log CFU g(-1) in winter, respectively. Our results revealed that both Salmonella and E. coli O157:H7 in compost samples with larger particle size survived better than those with smaller particle sizes, and the initial rapid moisture loss in compost may contribute to the fast inactivation of pathogens in the finished compost. For the same season, the pathogens in the compost samples with the same particle size survived much better at the initial moisture content of 20% compared to 40%.

  12. Temperature Effect Study on Growth and Survival of Pathogenic Vibrio parahaemolyticus in Jinjiang Oyster (Crassostrea rivularis with Rapid Count Method

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    Yuan Wang

    2018-01-01

    Full Text Available The growth of Vibrio parahaemolyticus (V. parahaemolyticus in oysters during postharvest storage increases the possibility of its infection in humans. In this work, to investigate the growth or survival profiles in different media, pathogenic V. parahaemolyticus in APW, Jinjiang oyster (JO, Crassostrea rivularis slurry, and live JO were studied under different temperatures. All the strain populations were counted through our double-layer agar plate (DLAP method. In APW, the pathogenic V. parahaemolyticus showed continuous growth under 15, 25, and 35°C, while a decline in behavior was displayed under 5°C. The similar survival trend of pathogenic V. parahaemolyticus in JO slurry and live JO was observed under 5, 25, and 35°C, except the delayed growth or decline profile compared to APW. Under 15°C, they displayed decline and growth profile in JO slurry and live JO, respectively. These results indicate the different sensitivity of pathogenic V. parahaemolyticus in these matrices to temperature variation. Furthermore, nonpathogenic V. parahaemolyticus displayed little difference in survival profiles when inoculated in live JO under corresponding temperatures. The results indicate that inhibition or promotion effect could be regulated under different storage temperature for both pathogenic and nonpathogenic strains. Besides, the DLAP method showed the obvious quickness and efficiency during the bacteria count.

  13. Highly pathogenic influenza A(H5N1 virus survival in complex artificial aquatic biotopes.

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    Viseth Srey Horm

    Full Text Available BACKGROUND: Very little is known regarding the persistence of Highly Pathogenic Avian Influenza (HPAI H5N1 viruses in aquatic environments in tropical countries, although environmental materials have been suggested to play a role as reservoirs and sources of transmission for H5N1 viruses. METHODOLOGY/PRINCIPAL FINDINGS: The survival of HPAI H5N1 viruses in experimental aquatic biotopes (water, mud, aquatic flora and fauna relevant to field conditions in Cambodia was investigated. Artificial aquatic biotopes, including simple ones containing only mud and water, and complex biotopes involving the presence of aquatic flora and fauna, were set up. They were experimentally contaminated with H5N1 virus. The persistence of HPAI H5N1 virus (local avian and human isolates was determined by virus isolation in embryonated chicken eggs and by real-time reverse-polymerase chain reaction. Persistence of infectious virus did not exceed 4 days, and was only identified in rain water. No infectious virus particles were detected in pond and lake water or mud even when high inoculum doses were used. However, viral RNA persisted up to 20 days in rain water and 7 days in pond or lake water. Viral RNA was also detected in mud samples, up to 14 days post-contamination in several cases. Infectious virus and viral RNA was detected in few cases in the aquatic fauna and flora, especially in bivalves and labyrinth fish, although these organisms seemed to be mostly passive carriers of the virus rather than host allowing virus replication. CONCLUSIONS/SIGNIFICANCE: Although several factors for the survival and persistence of HPAI viruses in the environment are still to be elucidated, and are particularly hard to control in laboratory conditions, our results, along with previous data, support the idea that environmental surveillance is of major relevance for avian influenza control programs.

  14. Glutamate uptake is important for osmoregulation and survival in the rice pathogen Burkholderia glumae.

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    Yongsung Kang

    Full Text Available Bacteria exhibit an optimal growth rate in culture media with sufficient nutrients at an optimal temperature and pH. In addition, the concentration of solutes plays a critical role in bacterial growth and survival. Glutamate is known to be a major anionic solute involved in osmoregulation and the bacterial cell's response to changes in solute concentration. To determine how glutamate uptake is involved in osmoregulation in the rice bacterial pathogen Burkholderia glumae BGR1, we mutated the gltI gene encoding a periplasmic substrate binding protein of a glutamate transport system to abolish glutamate uptake, and monitored the growth of the gltI null mutant in Luria-Bertani medium. We found that the gltI null mutant showed a slower growth rate than the wild-type strain and experienced hyperosmotic stress resulting in water loss from the cytoplasm in stationary phase. When the incubation time was extended, the mutant population collapsed due to the hyperosmotic stress. The gltI null mutant exhibited loss of adaptability under both hypoosmotic and hyperosmotic stresses. The growth rate of the gltI null mutant was restored to the level of wild-type growth by exogenous addition of glycine betaine to the culture medium, indicating that glycine betaine is a compatible solute in B. glumae. These results indicate that glutamate uptake from the environment plays a key role in osmoregulation in B. glumae.

  15. Pathogenic Dermatophytes Survive in Nail Lesions During Oral Terbinafine Treatment for Tinea Unguium.

    Science.gov (United States)

    Iwanaga, Tomoyuki; Ushigami, Tsuyoshi; Anzawa, Kazushi; Mochizuki, Takashi

    2017-08-01

    Tinea unguium caused by dermatophyte species are usually treated with oral antimycotic, terbinafine (TBF). To understand the mechanisms of improvement and recalcitrance of tinea unguium by oral TBF treatment, a method of quantifying dermatophyte viability in the nail was developed, and the viability of dermatophytes was analyzed in toenail lesions of 14 patients with KOH-positive tinea unguium treated with oral TBF 125 mg/day for up to 16 weeks. Mycological tests, including KOH examination and fungal culture, and targeted quantitative real-time PCR for internal transcribed spacer (ITS) region, including rRNA, were demonstrated at the initial visit and after 8 and 16 weeks of treatment. Assays in eight patients showed that average ITS DNA amount significantly decreased, to 44% at 8 weeks and 36% at 16 weeks compared with 100% at initial visit. No significant difference was observed between at 8 and 16 weeks, despite the TBF concentration in the nail supposedly more than 10-fold higher than the minimum fungicidal concentration for dermatophytes. This finding suggests the pathogenic dermatophytes in nail lesions could survive in a dormant form, such as arthroconidia, during oral TBF treatment. Both antimycotic activity and nail growth are important factors in treatment of tinea unguium.

  16. Physical and antimicrobial properties of anise oil loaded nanoemulsions on the survival of foodborne pathogens.

    Science.gov (United States)

    Topuz, Osman Kadir; Özvural, Emin Burçin; Zhao, Qin; Huang, Qingrong; Chikindas, Michael; Gölükçü, Muharrem

    2016-07-15

    The purpose of this research was to investigate antimicrobial effects of nano emulsions of anise oil (AO) on the survival of common food borne pathogens, Listeria monocytogenes and Escherichia coli O157:H7. Series of emulsions containing different level of anise oil as potential antimicrobial delivery systems were prepared. Antimicrobial activities of bulk anise oil and its emulsions (coarse and nano) was tested by the minimum inhibitory concentration and time kill assay. Our results showed that bulk anise oil reduced the population of E. coli O157:H7 and L. monocytogenes by 1.48 and 0.47 log cfu/ml respectively after 6 h of contact time. However, under the same condition anise oil nanoemulsion (AO75) reduced E. coli O157:H7 and L. monocytogenes count by 2.51 and 1.64 log cfu/ml, respectively. Physicochemical and microbial analyses indicated that both nano and coarse emulsions of anise oil showed better and long-term physicochemical stability and antimicrobial activity compared to bulk anise oil. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Survival of pathogenic enterohemorrhagic Escherichia coli (EHEC) and control with calcium oxide in frozen meat products.

    Science.gov (United States)

    Ro, Eun Young; Ko, Young Mi; Yoon, Ki Sun

    2015-08-01

    This study investigated both the level of microbial contamination and the presence of enterohemorrhagic Escherichia coli (EHEC) in frozen meat products, followed by the evaluation of its survival over 180 days under frozen temperature. We also examined the effect of calcium oxide on the populations of EHEC, E. coli O157:H7 and EPEC under both 10 °C and -18 °C storage conditions. Afterward, the morphological changes occurring in EHEC cells in response to freezer storage temperature and calcium oxide (CaO) treatments were examined using transmission electron microscopy. Among the frozen meat products tested, the highest contamination levels of total aerobic counts, coliforms and E. coli were observed in pork cutlets. Examination showed that 20% of the frozen meat products contained virulence genes, including verotoxin (VT) 1 and 2. Over 180 days of frozen storage and after 3 freeze-thaw cycles, the population of EHEC did not change regardless of the type of products or initial inoculated concentration, indicating the strong survival ability of EHEC. Subsequent testing revealed that the growth of three pathogenic E. coli strains was completely inhibited in meat patties prepared with 1% CaO, stored at 10 °C. However, the addition of 2% CaO was necessary to control the survival of EHEC, E. coli O157:H7 and EPEC in meat patties stored at -18 °C. CaO reduced the population of E. coli O157:H7 more effectively than the other EHEC and EPEC strains at both 10 °C and -18 °C. Transmission electron microscopy analysis revealed that exposed EHEC cells were resistant to the freezer storage temperature, although some cells incurred injury and death after several freeze-thaw cycles. Most of the cells exposed to CaO were found to have died or lost their cellular integrity and membranes, indicating that CaO has the potential to be used as a powerful antimicrobial agent for manufacturing frozen meat products. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Brucella abortus Induces a Warburg Shift in Host Metabolism That Is Linked to Enhanced Intracellular Survival of the Pathogen.

    Science.gov (United States)

    Czyż, Daniel M; Willett, Jonathan W; Crosson, Sean

    2017-08-01

    Intracellular bacterial pathogens exploit host cell resources to replicate and survive inside the host. Targeting these host systems is one promising approach to developing novel antimicrobials to treat intracellular infections. We show that human macrophage-like cells infected with Brucella abortus undergo a metabolic shift characterized by attenuated tricarboxylic acid cycle metabolism, reduced amino acid consumption, altered mitochondrial localization, and increased lactate production. This shift to an aerobic glycolytic state resembles the Warburg effect, a change in energy production that is well described in cancer cells and also occurs in activated inflammatory cells. B. abortus efficiently uses lactic acid as its sole carbon and energy source and requires the ability to metabolize lactate for normal survival in human macrophage-like cells. We demonstrate that chemical inhibitors of host glycolysis and lactate production do not affect in vitro growth of B. abortus in axenic culture but decrease its survival in the intracellular niche. Our data support a model in which infection shifts host metabolism to a Warburg-like state, and B. abortus uses this change in metabolism to promote intracellular survival. Pharmacological perturbation of these features of host cell metabolism may be a useful strategy to inhibit infection by intracellular pathogens. IMPORTANCE Brucella spp. are intracellular bacterial pathogens that cause disease in a range of mammals, including livestock. Transmission from livestock to humans is common and can lead to chronic human disease. Human macrophage-like cells infected with Brucella abortus undergo a Warburg-like metabolic shift to an aerobic glycolytic state where the host cells produce lactic acid and have reduced amino acid catabolism. We provide evidence that the pathogen can exploit this change in host metabolism to support growth and survival in the intracellular niche. Drugs that inhibit this shift in host cell metabolism

  19. The EbpA-RpoN Regulatory Pathway of the Pathogen Leptospira interrogans Is Essential for Survival in the Environment

    Science.gov (United States)

    Hu, Wei-Lin; Pappas, Christopher J.; Zhang, Jun-Jie; Yang, You-Yun; Yan, Jie

    2016-01-01

    ABSTRACT Leptospira interrogans is the agent of leptospirosis, a reemerging zoonotic disease. It is transmitted to humans through environmental surface waters contaminated by the urine of mammals chronically infected by pathogenic strains able to survive in water for long periods. Little is known about the regulatory pathways underlying environmental sensing and host adaptation of L. interrogans during its enzootic cycle. This study identifies the EbpA-RpoN regulatory pathway in L. interrogans. In this pathway, EbpA, a σ54 activator and putative prokaryotic enhancer-binding protein (EBP), and the alternative sigma factor RpoN (σ54) control expression of at least three genes, encoding AmtB (an ammonium transport protein) and two proteins of unknown function. Electrophoresis mobility shift assay demonstrated that recombinant RpoN and EbpA bind to the promoter region and upstream of these three identified genes, respectively. Genetic disruption of ebpA in L. interrogans serovar Manilae virtually abolished expression of the three genes, including amtB in two independent ebpA mutants. Complementation of the ebpA mutant restored expression of these genes. Intraperitoneal inoculation of gerbils with the ebpA mutant did not affect mortality. However, the ebpA mutant had decreased cell length in vitro and had a significantly lowered cell density at stationary phase when grown with l-alanine as the sole nitrogen source. Furthermore, the ebpA mutant has dramatically reduced long-term survival ability in water. Together, these studies identify a regulatory pathway, the EbpA-RpoN pathway, that plays an important role in the zoonotic cycle of L. interrogans. IMPORTANCE Leptospirosis is a reemerging disease with global importance. However, our understanding of gene regulation of the spirochetal pathogen Leptospira interrogans is still in its infancy, largely due to the lack of robust tools for genetic manipulation of this spirochete. Little is known about how the pathogen

  20. The EbpA-RpoN Regulatory Pathway of the Pathogen Leptospira interrogans Is Essential for Survival in the Environment.

    Science.gov (United States)

    Hu, Wei-Lin; Pappas, Christopher J; Zhang, Jun-Jie; Yang, You-Yun; Yan, Jie; Picardeau, Mathieu; Yang, X Frank

    2017-02-01

    Leptospira interrogans is the agent of leptospirosis, a reemerging zoonotic disease. It is transmitted to humans through environmental surface waters contaminated by the urine of mammals chronically infected by pathogenic strains able to survive in water for long periods. Little is known about the regulatory pathways underlying environmental sensing and host adaptation of L. interrogans during its enzootic cycle. This study identifies the EbpA-RpoN regulatory pathway in L. interrogans In this pathway, EbpA, a σ 54 activator and putative prokaryotic enhancer-binding protein (EBP), and the alternative sigma factor RpoN (σ 54 ) control expression of at least three genes, encoding AmtB (an ammonium transport protein) and two proteins of unknown function. Electrophoresis mobility shift assay demonstrated that recombinant RpoN and EbpA bind to the promoter region and upstream of these three identified genes, respectively. Genetic disruption of ebpA in L. interrogans serovar Manilae virtually abolished expression of the three genes, including amtB in two independent ebpA mutants. Complementation of the ebpA mutant restored expression of these genes. Intraperitoneal inoculation of gerbils with the ebpA mutant did not affect mortality. However, the ebpA mutant had decreased cell length in vitro and had a significantly lowered cell density at stationary phase when grown with l-alanine as the sole nitrogen source. Furthermore, the ebpA mutant has dramatically reduced long-term survival ability in water. Together, these studies identify a regulatory pathway, the EbpA-RpoN pathway, that plays an important role in the zoonotic cycle of L. interrogans IMPORTANCE: Leptospirosis is a reemerging disease with global importance. However, our understanding of gene regulation of the spirochetal pathogen Leptospira interrogans is still in its infancy, largely due to the lack of robust tools for genetic manipulation of this spirochete. Little is known about how the pathogen achieves its

  1. Effects of temperature, nutrients, organic matter and coral mucus on the survival of the coral pathogen, Serratia marcescens PDL100.

    Science.gov (United States)

    Looney, Erin E; Sutherland, Kathryn P; Lipp, Erin K

    2010-09-01

    Serratia marcescens is an enteric bacterium that causes white pox disease in elkhorn coral, Acropora palmata; however, it remains unclear if the pathogenic strain has adapted to seawater or if it requires a host or reservoir for survival. To begin to address this fundamental issue, the persistence of strain PDL100 was compared among seawater and coral mucus microcosms. Median survival time across all conditions ranged from a low of 15 h in natural seawater [with a first-order decay constant (k) = -0.173] at 30°C to a maximum of 120 h in glucose-amended A. palmata mucus (k = -0.029) at 30°C. Among seawater and mucus microcosms, median survival time was significantly greater within Siderastrea siderea mucus compared with seawater or mucus of Montastraea faveolata or A. palmata (P palmata mucus (P < 0.0001). Increasing the temperature of seawater to 35°C resulted in a significantly slower decay than that observed at 30°C (P < 0.0001). The results of this study indicate that PDL100 is not well-adapted to marine water; however, survival can be improved by increasing temperature, the availability of coral mucus from S. siderea and most notably the presence of dissolved organic carbon. © 2010 Society for Applied Microbiology and Blackwell Publishing Ltd.

  2. Survival behaviour and virulence of the fish pathogen Vibrio ordalii in seawater microcosms.

    Science.gov (United States)

    Ruiz, Pamela; Poblete-Morales, Matías; Irgang, Rute; Toranzo, Alicia E; Avendaño-Herrera, Ruben

    2016-06-15

    Vibrio ordalii, the causative agent of atypical vibriosis, is a Gram-negative, motile, rod-shaped bacterium that severely affects the salmonid aquaculture industry. V. ordalii has been biochemically, antigenically and genetically characterized. However, studies on the survival behaviour of this bacterium in aquatic environments are scarce, and there is no information regarding its disease transmission and infectious abilities outside of the fish host or regarding water as a possible reservoir. The present study investigated the survival behaviour of V. ordalii Vo-LM-06 and Vo-LM-18 in sterile and non-sterile seawater microcosms. After a year in sterile seawater without nutrients, 1% of both V. ordalii strains survived (~10(3) colony-forming units ml(-1)), and long-term maintenance did not affect bacterial biochemical or genetic properties. Additionally, V. ordalii maintained for 60 d in sterile seawater remained infective in rainbow trout Oncorhynchus mykiss. However, after 2 d of natural seawater exposure, this bacterium became non-culturable, indicating that autochthonous microbiota may play an important role in survival. Recuperation assays that added fresh medium to non-sterile microcosms did not favour V. ordalii recovery on solid media. Our results contribute towards a better understanding of V. ordalii survival behaviour in seawater ecosystems.

  3. Survival and High-Hydrostatic Pressure Inactivation of Foodborne Pathogens in Salmorejo, a Traditional Ready-to-Eat Food.

    Science.gov (United States)

    Toledo Del Árbol, Julia; Pérez Pulido, Rubén; Grande, Ma José; Gálvez, Antonio; Lucas, Rosario

    2015-11-01

    Salmorejo is a traditional tomato-based creamy product. Because salmorejo is not heat-processed, there is a risk of contamination with foodborne pathogens from raw materials. Even though bacterial growth in salmorejo is strongly inhibited because of its acidic pH (close to 3.9), the growth and survival of 3 foodborne pathogens in this food has not been studied before. In this study, 3 cocktails consisting of Escherichia coli O157, Salmonella enterica serovar Enteritidis, and Listeria monocytogenes strains were inoculated in freshly prepared salmorejo. The food was treated by high hydrostatic pressure (HHP) at 400, 500, or 600 MPa for 8 min, or left untreated, and stored at 4 °C for 30 d. Viable cell counts were determined on selective media and also by the triple-layer agar method in order to detect sublethally injured cells. In control samples, L. monocytogenes viable cells decreased by 2.4 log cycles at day 7 and were undetectable by day 15. S. enterica cells decreased by 0.5 or 2.4 log cycles at days 7 and 15 respectively, but still were detectable at day 30. E. coli O157 cells survived much better in salmorejo, decreasing only by 1.5 log cycles at day 30. Treatments at pressures of 400 MPa or higher reduced viable counts of L. monocytogenes and S. enterica to undetectable levels. HHP treatments significantly (P food, usually produced on a small scale. HHP treatment at 600 MPa for 8 min can be an efficient nonthermal method for industrial-scale preparation of preservative-free salmorejo with improved safety against transmission of foodborne pathogens L. monocytogenes serotyes 4a and 4b, S. enterica serovar Enteritidis, and E. coli O157. © 2015 Institute of Food Technologists®

  4. Correlation between the genetic diversity of nosocomial pathogens and their survival time in intensive care units.

    NARCIS (Netherlands)

    Gastmeier, P; Schwab, F; Bärwolff, S; Rüden, H; Grundmann, Hajo

    2006-01-01

    Bacteria differ in their ability to survive in the hospital environment outside the human host. Species remaining viable and infectious have a higher chance of being transmitted, giving them a fitness advantage in hospitals. This differential fitness could be expected to alter the genetic population

  5. Serine/Threonine Protein Phosphatase PstP of Mycobacterium tuberculosis Is Necessary for Accurate Cell Division and Survival of Pathogen*

    Science.gov (United States)

    Sharma, Aditya K.; Arora, Divya; Singh, Lalit K.; Gangwal, Aakriti; Sajid, Andaleeb; Molle, Virginie; Singh, Yogendra; Nandicoori, Vinay Kumar

    2016-01-01

    Protein phosphatases play vital roles in phosphorylation-mediated cellular signaling. Although there are 11 serine/threonine protein kinases in Mycobacterium tuberculosis, only one serine/threonine phosphatase, PstP, has been identified. Although PstP has been biochemically characterized and multiple in vitro substrates have been identified, its physiological role has not yet been elucidated. In this study, we have investigated the impact of PstP on cell growth and survival of the pathogen in the host. Overexpression of PstP led to elongated cells and partially compromised survival. We find that depletion of PstP is detrimental to cell survival, eventually leading to cell death. PstP depletion results in elongated multiseptate cells, suggesting a role for PstP in regulating cell division events. Complementation experiments performed with PstP deletion mutants revealed marginally compromised survival, suggesting that all of the domains, including the extracellular domain, are necessary for complete rescue. On the other hand, the catalytic activity of PstP is absolutely essential for the in vitro growth. Mice infection experiments establish a definitive role for PstP in pathogen survival within the host. Depletion of PstP from established infections causes pathogen clearance, indicating that the continued presence of PstP is necessary for pathogen survival. Taken together, our data suggest an important role for PstP in establishing and maintaining infection, possibly via the modulation of cell division events. PMID:27758870

  6. Honey Bee Survival and Pathogen Prevalence: From the Perspective of Landscape and Exposure to Pesticides

    Directory of Open Access Journals (Sweden)

    Mohamed Alburaki

    2018-06-01

    Full Text Available In order to study the in situ effects of the agricultural landscape and exposure to pesticides on honey bee health, sixteen honey bee colonies were placed in four different agricultural landscapes. Those landscapes were three agricultural areas with varying levels of agricultural intensity (AG areas and one non-agricultural area (NAG area. Colonies were monitored for different pathogen prevalence and pesticide residues over a period of one year. RT-qPCR was used to study the prevalence of seven different honey bee viruses as well as Nosema sp. in colonies located in different agricultural systems with various intensities of soybean, corn, sorghum, and cotton production. Populations of the parasitic mite Varroa destructor were also extensively monitored. Comprehensive MS-LC pesticide residue analyses were performed on samples of wax, honey, foragers, winter bees, dead bees, and crop flowers for each apiary and location. A significantly higher level of varroa loads were recorded in colonies of the AG areas, but this at least partly correlated with increased colony size and did not necessarily result from exposure to pesticides. Infections of two viruses (deformed wing virus genotype a (DWVa and acute bee paralysis virus (ABPV and Nosema sp. varied among the four studied locations. The urban location significantly elevated colony pathogen loads, while AG locations significantly benefited and increased the colony weight gain. Cotton and sorghum flowers contained high concentrations of insecticide including neonicotinoids, while soybean and corn had less pesticide residues. Several events of pesticide toxicity were recorded in the AG areas, and high concentrations of neonicotinoid insecticides were detected in dead bees.

  7. Pathogenic microorganisms survival in ambrosia
    Sobrevivência de micro-organismos patogênicos em ambrósia

    OpenAIRE

    Cláudio Dias Timm; Daiani Teixeira Silva; Priscila Alves Dias; Rita de Cássia Santos Conceição

    2013-01-01

    Ambrosia is a kind of dulce de leche homemade with milk, eggs and sugar. It is usually sold in free markets and it is largely consumed in South America. Food contamination by pathogenic microorganisms can occur during the food processing, in distribution centers, in retail markets or in the consumer’s homes. The aim of this study was to evaluate the survival in ambrosia of main pathogenic microorganisms eventually transmitted by dairy products. Ambrosia fractions were experimentally contamina...

  8. Comparative analysis of the survival and gene expression of pathogenic strains Vibrio harveyi after starvation.

    Science.gov (United States)

    Sun, Jingjing; Gao, Xiaojian; Qun, Jiang; Du, Xuedi; Bi, Keran; Zhang, Xiaojun; Lin, Li

    2016-11-01

    This study aimed to evaluate the survival and gene expression of Vibrio harveyi under starvation conditions. The microcosms V. harveyi were incubated in sterilized seawater for 4 weeks at room temperature. Overall, the cell numeration declined rapidly about 10 3 CFU/ml during starvation, with a tiny rebound at day 21. Scanning electron microscopy revealed that rod-shaped cells became sphere with a rippled cell surface. By polymerase chain reaction (PCR) assay, nine genes, named luxR, toxR, vhhB, flaA, topA, fur, rpoS, mreB and ftsZ, were detected in the non-starved cells. In the starved cells, the expression levels of the detected genes declined substantially ranging from 0.005-fold to 0.028-fold compared to the non-starved cells performed by reverse transcription quantitative real-time PCR with 16S rRNA as the internal control. In the recovering cells, the expression levels of the detected genes, except luxR and mreB, were upregulated dramatically compared to the wild, especially topA (23.720-fold), fur (39.400-fold) and toxR (9.837-fold), validating that the expressions of both the metabolism and virulence genes were important for growth and survival of V. harveyi. The results may shed a new light on understanding of stress adaptation in bacteria. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. Spore Acquisition and Survival of Ambrosia Beetles Associated with the Laurel Wilt Pathogen in Avocados after Exposure to Entomopathogenic Fungi

    Directory of Open Access Journals (Sweden)

    Pasco B. Avery

    2018-04-01

    Full Text Available Laurel wilt is a disease threatening the avocado industry in Florida. The causative agent of the disease is a fungus vectored by ambrosia beetles that bore into the trees. Until recently, management strategies for the vectors of the laurel wilt fungus relied solely on chemical control and sanitation practices. Beneficial entomopathogenic fungi (EPF are the most common and prevalent natural enemies of pathogen vectors. Laboratory experiments demonstrated that commercial strains of EPF can increase the mortality of the primary vector, Xyleborus glabratus, and potential alternative vectors, Xylosandrus crassiusculus, Xyleborus volvulus and Xyleborus bispinatus (Coleoptera: Curculionidae: Scolytinae. Our study provides baseline data for three formulated commercially-available entomopathogenic fungi used as potential biocontrol agents against X. crassiusculus, X. volvulus and X. bispinatus. The specific objectives were to determine: (1 the mean number of viable spores acquired per beetle species adult after being exposed to formulated fungal products containing different strains of EPF (Isaria fumosorosea, Metarhizium brunneum and Beauveria bassiana; and (2 the median and mean survival times using paper disk bioassays. Prior to being used in experiments, all fungal suspensions were adjusted to 2.4 × 106 viable spores/mL. The number of spores acquired by X. crassiusculus was significantly higher after exposure to B. bassiana, compared to the other fungal treatments. For X. volvulus, the numbers of spores acquired per beetle were significantly different amongst the different fungal treatments, and the sequence of spore acquisition rates on X. volvulus from highest to lowest was I. fumosorosea > M. brunneum > B. bassiana. After X. bispinatus beetles were exposed to the different suspensions, the rates of acquisition of spores per beetle amongst the different fungal treatments were similar. Survival estimates (data pooled across two tests indicated an

  10. Spore Acquisition and Survival of Ambrosia Beetles Associated with the Laurel Wilt Pathogen in Avocados after Exposure to Entomopathogenic Fungi.

    Science.gov (United States)

    Avery, Pasco B; Bojorque, Verónica; Gámez, Cecilia; Duncan, Rita E; Carrillo, Daniel; Cave, Ronald D

    2018-04-25

    Laurel wilt is a disease threatening the avocado industry in Florida. The causative agent of the disease is a fungus vectored by ambrosia beetles that bore into the trees. Until recently, management strategies for the vectors of the laurel wilt fungus relied solely on chemical control and sanitation practices. Beneficial entomopathogenic fungi (EPF) are the most common and prevalent natural enemies of pathogen vectors. Laboratory experiments demonstrated that commercial strains of EPF can increase the mortality of the primary vector, Xyleborus glabratus , and potential alternative vectors, Xylosandrus crassiusculus , Xyleborus volvulus and Xyleborus bispinatus (Coleoptera: Curculionidae: Scolytinae). Our study provides baseline data for three formulated commercially-available entomopathogenic fungi used as potential biocontrol agents against X. crassiusculus , X. volvulus and X. bispinatus. The specific objectives were to determine: (1) the mean number of viable spores acquired per beetle species adult after being exposed to formulated fungal products containing different strains of EPF ( Isaria fumosorosea , Metarhizium brunneum and Beauveria bassiana ); and (2) the median and mean survival times using paper disk bioassays. Prior to being used in experiments, all fungal suspensions were adjusted to 2.4 × 10⁶ viable spores/mL. The number of spores acquired by X. crassiusculus was significantly higher after exposure to B. bassiana , compared to the other fungal treatments. For X. volvulus , the numbers of spores acquired per beetle were significantly different amongst the different fungal treatments, and the sequence of spore acquisition rates on X. volvulus from highest to lowest was I. fumosorosea > M. brunneum > B. bassiana . After X. bispinatus beetles were exposed to the different suspensions, the rates of acquisition of spores per beetle amongst the different fungal treatments were similar. Survival estimates (data pooled across two tests) indicated an

  11. Pathogenic microorganisms survival in ambrosiaSobrevivência de micro-organismos patogênicos em ambrósia

    Directory of Open Access Journals (Sweden)

    Cláudio Dias Timm

    2013-09-01

    Full Text Available Ambrosia is a kind of dulce de leche homemade with milk, eggs and sugar. It is usually sold in free markets and it is largely consumed in South America. Food contamination by pathogenic microorganisms can occur during the food processing, in distribution centers, in retail markets or in the consumer’s homes. The aim of this study was to evaluate the survival in ambrosia of main pathogenic microorganisms eventually transmitted by dairy products. Ambrosia fractions were experimentally contaminated with Salmonella enterica subsp. enterica serotype Typhimurium, Escherichia coli O157:H7, Listeria monocytogenes and Staphylococcus aureus. Analysis to evaluate the microorganisms’ viability were made after storage for 0, 1, 2, 3, 5, 10, 20 and 30 days. Salmonella and L. monocytogenes were recovered from all samples during the 30 days of study. E. coli O157:H7 was isolated until the tenth day and S. aureus until the third day. It was demonstrated that important pathogenic microorganisms are able to survive up to 30 days in ambrosia, which makes this product a potential carrier of food-borne diseases. This work is the first study about the possibility of ambrosia transmitting relevant public-health danger pathogenic microorganisms. Ambrosia é um tipo de doce de leite preparado artesanalmente com leite, ovos e açúcar, comumente comercializado em feiras livres e muito consumido na América do Sul. A contaminação de alimentos por microrganismos patogênicos pode ocorrer durante as etapas de processamento, nos centros de distribuição, no mercado varejista ou na casa do consumidor. O trabalho teve como objetivo avaliar a sobrevivência em ambrosia dos principais microrganismos patogênicos eventualmente transmitidos por leite e derivados. Alíquotas de ambrosia foram experimentalmente contaminadas com Salmonella enterica subsp. enterica sorotipo Typhimurium, Escherichia coli O157:H7, Listeria monocytogenes e Staphylococcus aureus. Foram realizadas

  12. The Animal Pathogen-Like Type III Secretion System is Required for the Intracellular Survival of Burkholderia mallei within J774.2 Macrophages

    Science.gov (United States)

    2006-03-30

    for B. mallei are horses, donkeys, and mules (solipeds), but other animals, including mice, hamsters, guinea pigs, monkeys , lions, and dogs, are...Spa/Prg and Shigella Ipa/Mxi/Spa TTS networks, are important for in vitro and in vivo survival of these pathogenic Burkholderia species (9–12, 14, 15

  13. Effect of brine marination on survival and growth of spoilage and pathogenic bacteria during processing and subsequent storage of ready-to-eat shrimp (Pandalus borealis)

    DEFF Research Database (Denmark)

    Mejlholm, Ole; Devitt, Tina D.; Dalgaard, Paw

    2012-01-01

    The effect of brine marination at chill temperatures on survival and growth of spoilage and pathogenic bacteria during processing and subsequent storage of ready-to-eat cold water shrimp was studied. Survival and growth of Lactobacillus sakei, Listeria monocytogenes, Salmonella, Staphylococcus...... aureus and Vibrio parahaemolyticus were examined. The effect of brine composition and pH was determined in 12 screening experiments without addition of shrimp. Sixteen challenge tests with shrimp were then carried out to examine the effect of brine composition and storage temperature on survival...

  14. Quantification of Salmonella Survival and Infection in an In vitro Model of the Human Intestinal Tract as Proxy for Foodborne Pathogens

    Directory of Open Access Journals (Sweden)

    Lucas M. Wijnands

    2017-06-01

    Full Text Available Different techniques are available for assessing differences in virulence of bacterial foodborne pathogens. The use of animal models or human volunteers is not expedient for various reasons; the use of epidemiological data is often hampered by lack of crucial data. In this paper, we describe a static, sequential gastrointestinal tract (GIT model system in which foodborne pathogens are exposed to simulated gastric and intestinal contents of the human digestive tract, including the interaction of pathogens with the intestinal epithelium. The system can be employed with any foodborne bacterial pathogens. Five strains of Salmonella Heidelberg and one strain of Salmonella Typhimurium were used to assess the robustness of the system. Four S. Heidelberg strains originated from an outbreak, the fifth S. Heidelberg strain and the S. Typhimurium strain originated from routine meat inspections. Data from plate counts, collected for determining the numbers of surviving bacteria in each stage, were used to quantify both the experimental uncertainty and biological variability of pathogen survival throughout the system. For this, a hierarchical Bayesian framework using Markov chain Monte Carlo (MCMC was employed. The model system is able to distinguish serovars/strains for in vitro infectivity when accounting for within strain biological variability and experimental uncertainty.

  15. The survival of pathogens in soil treated with wastewater sludge and in potatoes grown in such soil.

    Science.gov (United States)

    Chale-Matsau, J R B; Snyman, H G

    2006-01-01

    The prevalence of pathogens on potatoes (Solanum tuberosum) grown in soil amended with a pathogen rich wastewater sludge was investigated. Bacteria of the family Enterobacteriaceae are important pathogens causing intestinal and systemic illness of humans and other animals. Type B sludge was used. Sludges investigated are the high metal and the low metal sludges. Microorganisms in the sludge-amended soil were using culture-based technique. Salmonella and E. coli were observed in tested soil samples. No microorganisms were isolated from control samples taken throughout the process of the experiment. At harvest time, some of the potato samples from LMS soil were contaminated. These potatoes were subjected to further investigation using molecular techniques (polymerase chain reaction) with fD1 and rP2 as primers. Organisms identified from the sequenced potato peel samples with the BLAST search tool included Enterobacter agglomerans (Pantoea agglomerans), several Buttiauxella spp., Pectobacterium spp., Erwinia spp. and a few Pantoea spp. Other than the E. agglomerans, which is commonly found in the gut and upper respiratory tract of humans and in the environment, all the other species identified were found to be mainly either plant or soil pathogens. The E. agglomerans are not primary pathogens but secondary opportunistic pathogens particularly in immunocompromised individuals. These results suggest that growing high risk crops using wastewater sludge contaminated soil may lead to limited infestation of produce with primary pathogens. It appears that the use of HMS due to early pathogen die-off provides less risk of infection than the LMS. However, proper treatment of wastewater sludge to reduce pathogen load is essential prior to its use as soil conditioner.

  16. Exploring new roles for the rpoS gene in the survival and virulence of the fire blight pathogen Erwinia amylovora.

    Science.gov (United States)

    Santander, Ricardo D; Monte-Serrano, Mercedes; Rodríguez-Herva, José J; López-Solanilla, Emilia; Rodríguez-Palenzuela, Pablo; Biosca, Elena G

    2014-12-01

    Erwinia amylovora causes fire blight in economically important plants of the family Rosaceae. This bacterial pathogen spends part of its life cycle coping with starvation and other fluctuating environmental conditions. In many Gram-negative bacteria, starvation and other stress responses are regulated by the sigma factor RpoS. We obtained an E. amylovora rpoS mutant to explore the role of this gene in starvation responses and its potential implication in other processes not yet studied in this pathogen. Results showed that E. amylovora needs rpoS to develop normal starvation survival and viable but nonculturable (VBNC) responses. Furthermore, this gene contributed to stationary phase cross-protection against oxidative, osmotic, and acid stresses and was essential for cross-protection against heat shock, but nonessential against acid shock. RpoS also mediated regulation of motility, exopolysaccharide synthesis, and virulence in immature loquats, but not in pear plantlets, and contributed to E. amylovora survival in nonhost tissues during incompatible interactions. Our results reveal some unique roles for the rpoS gene in E. amylovora and provide new knowledge on the regulation of different processes related to its ecology, including survival in different environments and virulence in immature fruits. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  17. Mycobacterium tuberculosis Modulates miR-106b-5p to Control Cathepsin S Expression Resulting in Higher Pathogen Survival and Poor T-Cell Activation

    Directory of Open Access Journals (Sweden)

    David Pires

    2017-12-01

    Full Text Available The success of tuberculosis (TB bacillus, Mycobacterium tuberculosis (Mtb, relies on the ability to survive in host cells and escape to immune surveillance and activation. We recently demonstrated that Mtb manipulation of host lysosomal cathepsins in macrophages leads to decreased enzymatic activity and pathogen survival. In addition, while searching for microRNAs (miRNAs involved in posttranscriptional gene regulation during mycobacteria infection of human macrophages, we found that selected miRNAs such as miR-106b-5p were specifically upregulated by pathogenic mycobacteria. Here, we show that miR-106b-5p is actively manipulated by Mtb to ensure its survival in macrophages. Using an in silico prediction approach, we identified miR-106b-5p with a potential binding to the 3′-untranslated region of cathepsin S (CtsS mRNA. We demonstrated by luminescence-based methods that miR-106b-5p indeed targets CTSS mRNA resulting in protein translation silencing. Moreover, miR-106b-5p gain-of-function experiments lead to a decreased CtsS expression favoring Mtb intracellular survival. By contrast, miR-106b-5p loss-of-function in infected cells was concomitant with increased CtsS expression, with significant intracellular killing of Mtb and T-cell activation. Modulation of miR-106b-5p did not impact necrosis, apoptosis or autophagy arguing that miR-106b-5p directly targeted CtsS expression as a way for Mtb to avoid exposure to degradative enzymes in the endocytic pathway. Altogether, our data suggest that manipulation of miR-106b-5p as a potential target for host-directed therapy for Mtb infection.

  18. Effects of gamma and electron beam irradiation on the survival of pathogens inoculated into sliced and pizza cheeses

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun-Joo [Department of Food Science and Technology, Chung-Ang University, Ansung, Gyunggi-do 456-756 (Korea, Republic of); Ham, Jun-Sang [Animal Products Processing Division, National Livestock Research Institute, RDA, Suwon 441-706 (Korea, Republic of); Lee, Ju-Woon [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580-185 (Korea, Republic of); Kim, Keehyuk [Department of Culinary Nutrition, Woosong University, Daejeon 300-718 (Korea, Republic of); Ha, Sang-Do [Department of Food Science and Technology, Chung-Ang University, Ansung, Gyunggi-do 456-756 (Korea, Republic of); Jo, Cheorun, E-mail: cheorun@cnu.ac.k [Department of Animal Science and Biotechnology, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

    2010-06-15

    The objective of this study was to identify the efficacy of gamma and electron beam irradiation of the food-borne pathogens (Listeria monocytogenes and Staphylococcus aureus) in sliced and pizza cheeses commercially available in the Korean market. Total aerobic bacteria and yeast/mold in the cheeses ranged from 10{sup 2} to 10{sup 3} Log CFU/g. Irradiation of 1 kGy for sliced cheese and 3 kGy for pizza cheese were sufficient to lower the total aerobic bacteria to undetectable levels (10{sup 1} CFU/g). Pathogen inoculation test revealed that gamma irradiation was more effective than electron beam irradiation at the same absorbed dose, and the ranges of the D{sub 10} values were from 0.84 to 0.93 kGy for L. monocytogenes and from 0.60 to 0.63 kGy for S. aureus. Results suggest that a low dose irradiation can improve significantly the microbial quality and reduce the risk of contamination of sliced and pizza cheeses by the food-borne pathogens which can potentially occur during processing.

  19. Effects of gamma and electron beam irradiation on the survival of pathogens inoculated into sliced and pizza cheeses

    International Nuclear Information System (INIS)

    Kim, Hyun-Joo; Ham, Jun-Sang; Lee, Ju-Woon; Kim, Keehyuk; Ha, Sang-Do; Jo, Cheorun

    2010-01-01

    The objective of this study was to identify the efficacy of gamma and electron beam irradiation of the food-borne pathogens (Listeria monocytogenes and Staphylococcus aureus) in sliced and pizza cheeses commercially available in the Korean market. Total aerobic bacteria and yeast/mold in the cheeses ranged from 10 2 to 10 3 Log CFU/g. Irradiation of 1 kGy for sliced cheese and 3 kGy for pizza cheese were sufficient to lower the total aerobic bacteria to undetectable levels (10 1 CFU/g). Pathogen inoculation test revealed that gamma irradiation was more effective than electron beam irradiation at the same absorbed dose, and the ranges of the D 10 values were from 0.84 to 0.93 kGy for L. monocytogenes and from 0.60 to 0.63 kGy for S. aureus. Results suggest that a low dose irradiation can improve significantly the microbial quality and reduce the risk of contamination of sliced and pizza cheeses by the food-borne pathogens which can potentially occur during processing.

  20. Effects of gamma and electron beam irradiation on the survival of pathogens inoculated into sliced and pizza cheeses

    Science.gov (United States)

    Kim, Hyun-Joo; Ham, Jun-Sang; Lee, Ju-Woon; Kim, Keehyuk; Ha, Sang-Do; Jo, Cheorun

    2010-06-01

    The objective of this study was to identify the efficacy of gamma and electron beam irradiation of the food-borne pathogens ( Listeria monocytogenes and Staphylococcus aureus) in sliced and pizza cheeses commercially available in the Korean market. Total aerobic bacteria and yeast/mold in the cheeses ranged from 10 2 to 10 3 Log CFU/g. Irradiation of 1 kGy for sliced cheese and 3 kGy for pizza cheese were sufficient to lower the total aerobic bacteria to undetectable levels (10 1 CFU/g). Pathogen inoculation test revealed that gamma irradiation was more effective than electron beam irradiation at the same absorbed dose, and the ranges of the D 10 values were from 0.84 to 0.93 kGy for L. monocytogenes and from 0.60 to 0.63 kGy for S. aureus. Results suggest that a low dose irradiation can improve significantly the microbial quality and reduce the risk of contamination of sliced and pizza cheeses by the food-borne pathogens which can potentially occur during processing.

  1. Comparative Analyses of Nonpathogenic, Opportunistic, and Totally Pathogenic Mycobacteria Reveal Genomic and Biochemical Variabilities and Highlight the Survival Attributes of Mycobacterium tuberculosis

    Science.gov (United States)

    Singh, Yadvir; Kohli, Sakshi; Ahmad, Javeed; Ehtesham, Nasreen Z.; Tyagi, Anil K.

    2014-01-01

    ABSTRACT Mycobacterial evolution involves various processes, such as genome reduction, gene cooption, and critical gene acquisition. Our comparative genome size analysis of 44 mycobacterial genomes revealed that the nonpathogenic (NP) genomes were bigger than those of opportunistic (OP) or totally pathogenic (TP) mycobacteria, with the TP genomes being smaller yet variable in size—their genomic plasticity reflected their ability to evolve and survive under various environmental conditions. From the 44 mycobacterial species, 13 species, representing TP, OP, and NP, were selected for genomic-relatedness analyses. Analysis of homologous protein-coding genes shared between Mycobacterium indicus pranii (NP), Mycobacterium intracellulare ATCC 13950 (OP), and Mycobacterium tuberculosis H37Rv (TP) revealed that 4,995 (i.e., ~95%) M. indicaus pranii proteins have homology with M. intracellulare, whereas the homologies among M. indicus pranii, M. intracellulare ATCC 13950, and M. tuberculosis H37Rv were significantly lower. A total of 4,153 (~79%) M. indicus pranii proteins and 4,093 (~79%) M. intracellulare ATCC 13950 proteins exhibited homology with the M. tuberculosis H37Rv proteome, while 3,301 (~82%) and 3,295 (~82%) M. tuberculosis H37Rv proteins showed homology with M. indicus pranii and M. intracellulare ATCC 13950 proteomes, respectively. Comparative metabolic pathway analyses of TP/OP/NP mycobacteria showed enzymatic plasticity between M. indicus pranii (NP) and M. intracellulare ATCC 13950 (OP), Mycobacterium avium 104 (OP), and M. tuberculosis H37Rv (TP). Mycobacterium tuberculosis seems to have acquired novel alternate pathways with possible roles in metabolism, host-pathogen interactions, virulence, and intracellular survival, and by implication some of these could be potential drug targets. PMID:25370496

  2. Surface survival and internalization of salmonella through natural cracks on developing cantaloupe fruits, alone or in the presence of the melon wilt pathogen Erwinia tracheiphila.

    Directory of Open Access Journals (Sweden)

    Dhiraj Gautam

    Full Text Available Outbreaks of foodborne illness attributed to the consumption of Salmonella-tainted cantaloupe have occurred repeatedly, but understanding of the ecology of Salmonella on cantaloupe fruit surfaces is limited. We investigated the interactions between Salmonella enterica Poona, the plant pathogenic bacterium Erwinia tracheiphila, and cantaloupe fruit. Fruit surfaces were inoculated at the natural cracking stage by spreading S. enterica and E. tracheiphila, 20 µl at 107 cfu/ml, independently or together, over a 2×2 cm rind area containing a crack. Microbial and microscopic analyses were performed at 0, 9 and 24 days post inoculation (DPI. Even at 24 DPI (fruit maturity S. enterica was detected on 14% and 40% of the fruit inoculated with S. enterica alone and the two-pathogen mixture, respectively. However, the population of S. enterica declined gradually after initial inoculation. E. tracheiphila, inoculated alone or together with Salmonella, caused watersoaked lesions on cantaloupe fruit; but we could not conclude in this study that S. enterica survival on the fruit surface was enhanced by the presence of those lesions. Of fruit inoculated with E. tracheiphila alone and sampled at 24 DPI, 61% had watersoaked lesions on the surface. In nearly half of those symptomatic fruits the watersoaking extended into the sub-rind mesocarp, and E. tracheiphila was recovered from that tissue in 50% of the symptomatic fruit. In this work, E. tracheiphila internalized through natural cracks on developing fruits. S. enterica was never detected in the fruit interior (ca. 2-3 mm below rind surface under the limited conditions of our experiments, but the possibility that it, or other human pathogens that contaminate fresh produce, might also do so should be investigated under a wider range of conditions and produce types.

  3. Feline leukemia virus and other pathogens as important threats to the survival of the critically endangered Iberian lynx (Lynx pardinus.

    Directory of Open Access Journals (Sweden)

    Marina L Meli

    Full Text Available The Iberian lynx (Lynx pardinus is considered the most endangered felid species in the world. In order to save this species, the Spanish authorities implemented a captive breeding program recruiting lynxes from the wild. In this context, a retrospective survey on prevalence of selected feline pathogens in free-ranging lynxes was initiated.We systematically analyzed the prevalence and importance of seven viral, one protozoan (Cytauxzoon felis, and several bacterial (e.g., hemotropic mycoplasma infections in 77 of approximately 200 remaining free-ranging Iberian lynxes of the Doñana and Sierra Morena areas, in Southern Spain, between 2003 and 2007. With the exception of feline immunodeficiency virus (FIV, evidence of infection by all tested feline pathogens was found in Iberian lynxes. Fourteen lynxes were feline leukemia virus (FeLV provirus-positive; eleven of these were antigenemic (FeLV p27 positive. All 14 animals tested negative for other viral infections. During a six-month period in 2007, six of the provirus-positive antigenemic lynxes died. Infection with FeLV but not with other infectious agents was associated with mortality (p<0.001. Sequencing of the FeLV surface glycoprotein gene revealed a common origin for ten of the eleven samples. The ten sequences were closely related to FeLV-A/61E, originally isolated from cats in the USA. Endogenous FeLV sequences were not detected.It was concluded that the FeLV infection most likely originated from domestic cats invading the lynx's habitats. Data available regarding the time frame, co-infections, and outcome of FeLV-infections suggest that, in contrast to the domestic cat, the FeLV strain affecting the lynxes in 2007 is highly virulent to this species. Our data argue strongly for vaccination of lynxes and domestic cats in and around lynx's habitats in order to prevent further spread of the virus as well as reduction the domestic cat population if the lynx population is to be maintained.

  4. Depletion of autophagy-related genes ATG3 and ATG5 in Tenebrio molitor leads to decreased survivability against an intracellular pathogen, Listeria monocytogenes.

    Science.gov (United States)

    Tindwa, Hamisi; Jo, Yong Hun; Patnaik, Bharat Bhusan; Noh, Mi Young; Kim, Dong Hyun; Kim, Iksoo; Han, Yeon Soo; Lee, Yong Seok; Lee, Bok Luel; Kim, Nam Jung

    2015-01-01

    Macroautophagy (autophagy) is an evolutionarily conserved catabolic process involved in physiological and developmental processes including cell survival, death, and innate immunity. Homologues of most of 36 originally discovered autophagy-related (ATG) genes in yeast have been characterized in higher eukaryotes including insects. In this study, the homologues of ATG3 (TmATG3) and ATG5 (TmATG5) were isolated from the coleopteran beetle, Tenebrio molitor by expressed sequence tag and RNAseq approaches. The cDNA of TmATG3 and TmATG5 comprise open-reading frame sizes of 963 and 792 bp encoding polypeptides of 320 and 263 amino acid residues, respectively. TmATG3 and TmATG5 mRNA are expressed in all developmental stages, and mainly in fat body and hemocytes of larvae. TmATG3 and TmATG5 showed an overall sequence identity of 58-95% to other insect Atg proteins. There exist clear one-to-one orthologs of TmATG3 and TmATG5 in Tribolium and that they clustered together in the gene tree. Depletion of TmATG3 and TmATG5 by RNA interference led to a significant reduction in survival ability of T. molitor larvae against an intracellular pathogen, Listeria monocytogenes. Six days post-Listeria challenge, the survival rate in the dsEGFP-injected (where EGFP is enhanced green fluorescent protein) control larvae was significantly higher (55%) compared to 4 and 3% for TmATG3 and TmATG5 double-stranded RNA injected larvae, respectively. These data suggested that TmATG3 and TmATG5 may play putative role in mediating autophagy-based clearance of Listeria in T. molitor model. © 2014 Wiley Periodicals, Inc.

  5. Survival of foodborne pathogens (Escherichia coli O157:H7, Salmonella Typhimurium, Staphylococcus aureus, Listeria monocytogenes, and Vibrio parahaemolyticus) in raw ready-to-eat crab marinated in soy sauce.

    Science.gov (United States)

    Cho, T J; Kim, N H; Kim, S A; Song, J H; Rhee, M S

    2016-12-05

    Knowing the survival characteristics of foodborne pathogens in raw ready-to-eat (RTE) seafood is the key to predicting whether they pose a microbiological hazard. The present study examined the survival of Escherichia coli O157:H7, Salmonella Typhimurium, Vibrio parahaemoliticus, Listeria monocytogenes, and Staphylococcus aureus in raw RTE crab marinated in soy sauce. Inoculated crabs (initial bacterial population=4.1-4.4logCFU/g) were immersed in soy sauce and then stored at refrigeration (5°C) or room temperature (22°C) for up to 28days. At 5°C, all bacteria (except V. parahaemolyticus) survived in crab samples until Day 28 (counts of 1.4, 1.6, 3.1, 3.2 log CFU/g for E. coli O157:H7, S. Typhimurium, L. monocytogenes, and S. aureus, respectively). However, at 22°C, all tested bacteria were more susceptible to the antimicrobial effects of marination. Regardless of temperature, foodborne pathogens attached to crab samples were more resistant to marination than those suspended in soy sauce samples; however, the survival pattern for each species was different. Gram-positive bacteria were most resistant to marination conditions (high salinity, low pH), whereas V. parahaemolyticus was extremely susceptible. Marination is the only antibacterial step in the manufacturing processes; however, the results presented herein reveal that this is not sufficient to inactivate foodborne pathogens. In particular, the survival of pathogens on crabs at refrigeration temperature may pose a major hazard for the consumption of raw RTE seafood. Thus, appropriate decontamination methods and implementation of safety management practices are needed. This study provides predictive microbiological information of foodborne pathogens in raw RTE seafood with marination. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. AMPK in Pathogens

    OpenAIRE

    Mesquita, Inês Morais; Moreira, Diana; Marques, Belém Sampaio; Laforge, Mireille; Cordeiro-da-Silva, Anabela; Ludovico, Paula; Estaquier, Jérôme; Silvestre, Ricardo Jorge Leal

    2016-01-01

    During host–pathogen interactions, a complex web of events is crucial for the outcome of infection. Pathogen recognition triggers powerful cellular signaling events that is translated into the induction and maintenance of innate and adaptive host immunity against infection. In opposition, pathogens employ active mechanisms to manipulate host cell regulatory pathways toward their proliferation and survival. Among these, subversion of host cell energy metabolism by pathogens is currently recogn...

  7. Quantification of Salmonella Survival and Infection in an In vitro Model of the Human Intestinal Tract as Proxy for Foodborne Pathogens.

    NARCIS (Netherlands)

    Wijnands, Lucas M; Teunis, Peter F M; Kuijpers, Angelina F A; Delfgou-Van Asch, Ellen H M; Pielaat, Annemarie

    2017-01-01

    Different techniques are available for assessing differences in virulence of bacterial foodborne pathogens. The use of animal models or human volunteers is not expedient for various reasons; the use of epidemiological data is often hampered by lack of crucial data. In this paper, we describe a

  8. AMPK in Pathogens.

    Science.gov (United States)

    Mesquita, Inês; Moreira, Diana; Sampaio-Marques, Belém; Laforge, Mireille; Cordeiro-da-Silva, Anabela; Ludovico, Paula; Estaquier, Jérôme; Silvestre, Ricardo

    2016-01-01

    During host-pathogen interactions, a complex web of events is crucial for the outcome of infection. Pathogen recognition triggers powerful cellular signaling events that is translated into the induction and maintenance of innate and adaptive host immunity against infection. In opposition, pathogens employ active mechanisms to manipulate host cell regulatory pathways toward their proliferation and survival. Among these, subversion of host cell energy metabolism by pathogens is currently recognized to play an important role in microbial growth and persistence. Extensive studies have documented the role of AMP-activated protein kinase (AMPK) signaling, a central cellular hub involved in the regulation of energy homeostasis, in host-pathogen interactions. Here, we highlight the most recent advances detailing how pathogens hijack cellular metabolism by suppressing or increasing the activity of the host energy sensor AMPK. We also address the role of lower eukaryote AMPK orthologues in the adaptive process to the host microenvironment and their contribution for pathogen survival, differentiation, and growth. Finally, we review the effects of pharmacological or genetic AMPK modulation on pathogen growth and persistence.

  9. Incidence of and survival after subsequent cancers in carriers of pathogenic MMR variants with previous cancer : a report from the prospective Lynch syndrome database

    NARCIS (Netherlands)

    Møller, Pål; Seppälä, Toni; Bernstein, Inge; Holinski-Feder, Elke; Sala, Paola; Evans, D Gareth; Lindblom, Annika; Macrae, Finlay; Blanco, Ignacio; Sijmons, Rolf; Jeffries, Jacqueline; Vasen, Hans; Burn, John; Nakken, Sigve; Hovig, Eivind; Rødland, Einar Andreas; Tharmaratnam, Kukatharmini; de Vos Tot Nederveen Cappel, Wouter H; Hill, James; Wijnen, Juul; Jenkins, Mark; Green, Kate; Lalloo, Fiona; Sunde, Lone; Mints, Miriam; Bertario, Lucio; Pineda, Marta; Navarro, Matilde; Morak, Monika; Renkonen-Sinisalo, Laura; Frayling, Ian M; Plazzer, John-Paul; Pylvanainen, Kirsi; Genuardi, Maurizio; Mecklin, Jukka-Pekka; Möslein, Gabriela; Sampson, Julian R; Capella, Gabriel

    2016-01-01

    Objective Today most patients with Lynch syndrome (LS) survive their first cancer. There is limited information on the incidences and outcome of subsequent cancers. The present study addresses three questions: (i) what is the cumulative incidence of a subsequent cancer; (ii) in which organs do

  10. Effects of the Essential Oil from Origanum vulgare L. on Survival of Pathogenic Bacteria and Starter Lactic Acid Bacteria in Semihard Cheese Broth and Slurry.

    Science.gov (United States)

    de Souza, Geany Targino; de Carvalho, Rayssa Julliane; de Sousa, Jossana Pereira; Tavares, Josean Fechine; Schaffner, Donald; de Souza, Evandro Leite; Magnani, Marciane

    2016-02-01

    This study assessed the inhibitory effects of the essential oil from Origanum vulgare L. (OVEO) on Staphylococcus aureus, Listeria monocytogenes, and a mesophilic starter coculture composed of lactic acid bacteria (Lactococcus lactis subsp. lactis and L. lactis subsp. cremoris) in Brazilian coalho cheese systems. The MIC of OVEO was 2.5 μl/ml against both S. aureus and L. monocytogenes and 0.6 μl/ml against the tested starter coculture. In cheese broth containing OVEO at 0.6 μl/ml, no decrease in viable cell counts (VCC) of both pathogenic bacteria was observed, whereas the initial VCC of the starter coculture decreased approximately 1.0 log CFU/ml after 24 h of exposure at 10°C. OVEO at 1.25 and 2.5 μl/ml caused reductions of up to 2.0 and 2.5 log CFU/ml in S. aureus and L. monocytogenes, respectively, after 24 h of exposure in cheese broth. At these same concentrations, OVEO caused a greater decrease of initial VCC of the starter coculture following 4 h of exposure. Higher concentrations of OVEO were required to decrease the VCC of all target bacteria in semisolid coalho cheese slurry compared with cheese broth. The VCC of Lactococcus spp. in coalho cheese slurry containing OVEO were always lower than those of pathogenic bacteria under the same conditions. These results suggest that the concentrations of OVEO used to control pathogenic bacteria in semihard cheese should be carefully evaluated because of its inhibitory effects on the growth of starter lactic acid cultures used during the production of the product.

  11. Survival of pathogens on soybean debris under no-tillage and conventional tillage systems Sobrevivência de patógenos em restos de cultura de soja mantidos em sistema de semeadura direta e convencional

    Directory of Open Access Journals (Sweden)

    Álvaro Manuel Rodrigues Almeida

    2001-10-01

    Full Text Available A study was conducted in the subtropical area of Southern Brazil to determine the survival of pathogens in soybean residues under conventional and no-tillage cultivation systems from March to September of 1998 and 1999. The pathogens most frequently isolated were Colletotrichum truncatum, Phomopsis spp., Cercospora kikuchii, Fusarium spp., Macrophomina phaseolina, and Rhizoctonia solani. Other fungi isolated were Myrothecium roridum, Penicillium sp., Chaetomium sp., Epicoccum sp., Corynespora cassiicola and Trichoderma sp. The percent of survival of each pathogen varied according to the month and the year. Survival of C. truncatum, Phomopsis spp. and C. kikuchii were significantly reduced (pAvaliou-se a sobrevivência de patógenos em restos de soja, em sistema de semeadura direta e convencional, entre março e setembro de 1998 e 1999, em Londrina, PR. Os patógenos mais freqüentemente isolados foram Colletotrichum truncatum, Phomopsis spp., Cercospora kikuchii, Fusarium spp., Macrophomina phaseolina e Rhizoctonia solani. Outros fungos isolados foram Myrothecium roridum, Penicillium sp., Chaetomium sp., Epicoccum sp., Corynespora cassiicola e Trichoderma sp. A porcentagem de sobrevivência variou com o mês e o ano. A sobrevivência de C. truncatum, Phomopsis spp. e C. kikuchii foi significativamente reduzida (P<0,05 entre a primeira e última avaliação nos resíduos mantidos sobre ou sob o solo. M. phaseolina e Fusarium spp. não foram afetados, ou foram favorecidos pelo enterro dos resíduos. A freqüência de isolamento de Fusarium spp. aumentou em resíduos enterrados no solo. A perda de biomassa mostrou redução de 44,4% no sistema convencional e 34,9% no sistema de semeadura direta, em 1998, quando a distribuição de chuvas foi mais regular. Em 1999, a redução foi de 48,2% e 39,0% para os sistemas convencional e de semeadura direta, respectivamente.

  12. The Wnt receptor Ryk reduces neuronal and cell survival capacity by repressing FOXO activity during the early phases of mutant huntingtin pathogenicity.

    Directory of Open Access Journals (Sweden)

    Cendrine Tourette

    2014-06-01

    Full Text Available The Wnt receptor Ryk is an evolutionary-conserved protein important during neuronal differentiation through several mechanisms, including γ-secretase cleavage and nuclear translocation of its intracellular domain (Ryk-ICD. Although the Wnt pathway may be neuroprotective, the role of Ryk in neurodegenerative disease remains unknown. We found that Ryk is up-regulated in neurons expressing mutant huntingtin (HTT in several models of Huntington's disease (HD. Further investigation in Caenorhabditis elegans and mouse striatal cell models of HD provided a model in which the early-stage increase of Ryk promotes neuronal dysfunction by repressing the neuroprotective activity of the longevity-promoting factor FOXO through a noncanonical mechanism that implicates the Ryk-ICD fragment and its binding to the FOXO co-factor β-catenin. The Ryk-ICD fragment suppressed neuroprotection by lin-18/Ryk loss-of-function in expanded-polyQ nematodes, repressed FOXO transcriptional activity, and abolished β-catenin protection of mutant htt striatal cells against cell death vulnerability. Additionally, Ryk-ICD was increased in the nucleus of mutant htt cells, and reducing γ-secretase PS1 levels compensated for the cytotoxicity of full-length Ryk in these cells. These findings reveal that the Ryk-ICD pathway may impair FOXO protective activity in mutant polyglutamine neurons, suggesting that neurons are unable to efficiently maintain function and resist disease from the earliest phases of the pathogenic process in HD.

  13. Effects of bile salt deconjugation by probiotic strains on the survival of antibiotic-resistant foodborne pathogens under simulated gastric conditions.

    Science.gov (United States)

    He, Xinlong; Zou, Yunyun; Cho, Youngjae; Ahn, Juhee

    2012-06-01

    This study was designed to evaluate the effects of bile acid deconjugation by probiotic strains on the antibiotic susceptibility of antibiotic-sensitive and multiple antibiotic-resistant Salmonella Typhimurium and Staphylococcus aureus. Eight probiotic strains, Bifidobacterium longum B6, Lactobacillus acidophilus ADH, Lactobacillus brevis KACC 10553, Lactobacillus casei KACC 12413, Lactobacillus paracasei ATCC 25598, Lactobacillus rhamnosus GG, Leuconostoc mesenteroides KACC 12312, and Pediococcus acidilactici KACC 12307, were used to examine bile acid tolerance. The ability to deconjugate bile acids was evaluated using both thin-layer chromatography and high-performance liquid chromatography. The antibiotic susceptibility testing was carried out to determine the synergistic inhibitory activity of deconjugated bile acids. L. acidophilus, L. brevis, and P. acidilactici showed the most tolerance to the conjugated bile acids. P. acidilactici deconjugated glycocholic acid and glycodeoxycholate from 3.18 and 3.09 mM to the detection limits, respectively. The antibiotic susceptibility of selected foodborne pathogens was increased by increasing the concentration of deconjugated bile acids. The study results are useful for understanding the relationship between bile acid deconjugation by probiotic strains and antibiotic susceptibility in the presence of deconjugated bile acids, and they may be useful for designing new probiotic-antibiotic combination therapy based on bile acid deconjugation.

  14. Growth inhibition of pathogenic bacteria and some yeasts by selected essential oils and survival of L. monocytogenes and C. albicans in apple-carrot juice.

    Science.gov (United States)

    Irkin, Reyhan; Korukluoglu, Mihriban

    2009-04-01

    Food safety is a fundamental concern of both consumers and the food industry. The increasing incidence of foodborne diseases increases the demand of using antimicrobials in foods. Spices and plants are rich in essential oils and show inhibition activity against microorganisms, which are composed of many compounds. In this research, effects of garlic, bay, black pepper, origanum, orange, thyme, tea tree, mint, clove, and cumin essential oils on Listeria monocytogenes AUFE 39237, Escherichia coli ATCC 25922, Salmonella enteritidis ATCC 13076, Proteus mirabilis AUFE 43566, Bacillus cereus AUFE 81154, Saccharomyces uvarum UUFE 16732, Kloeckera apiculata UUFE 10628, Candida albicans ATCC 10231, Candida oleophila UUPP 94365, and Metschnikowia fructicola UUPP 23067 and effects of thyme oil at a concentration of 0.5% on L. monocytogenes and C. albicans in apple-carrot juice during +4 degrees C storage (first to fifth day) were investigated. Strong antibacterial and antifungal activities of some essential oils were found. Thyme, origanum, clove, and orange essential oils were the most inhibitory against bacteria and yeasts. Cumin, tea tree, and mint oils inhibited the yeasts actively. It is concluded that some essential oils could be used as potential biopreservatives capable of controlling foodborne pathogens and food spoilage yeasts.

  15. Pathogen inactivation techniques.

    Science.gov (United States)

    Pelletier, J P R; Transue, S; Snyder, E L

    2006-01-01

    The desire to rid the blood supply of pathogens of all types has led to the development of many technologies aimed at the same goal--eradication of the pathogen(s) without harming the blood cells or generating toxic chemical agents. This is a very ambitious goal, and one that has yet to be achieved. One approach is to shun the 'one size fits all' concept and to target pathogen-reduction agents at the Individual component types. This permits the development of technologies that might be compatible with, for example, plasma products but that would be cytocidal and thus incompatible with platelet concentrates or red blood cell units. The technologies to be discussed include solvent detergent and methylene blue treatments--designed to inactivate plasma components and derivatives; psoralens (S-59--amotosalen) designed to pathogen-reduce units of platelets; and two products aimed at red blood cells, S-303 (a Frale--frangible anchor-linker effector compound) and Inactine (a binary ethyleneimine). A final pathogen-reduction material that might actually allow one material to inactivate all three blood components--riboflavin (vitamin B2)--is also under development. The sites of action of the amotosalen (S-59), the S-303 Frale, Inactine, and riboflavin are all localized in the nucleic acid part of the pathogen. Solvent detergent materials act by dissolving the plasma envelope, thus compromising the integrity of the pathogen membrane and rendering it non-infectious. By disrupting the pathogen's ability to replicate or survive, its infectivity is removed. The degree to which bacteria and viruses are affected by a particular pathogen-reducing technology relates to its Gram-positive or Gram-negative status, to the sporulation characteristics for bacteria, and the presence of lipid or protein envelopes for viruses. Concerns related to photoproducts and other breakdown products of these technologies remain, and the toxicology of pathogen-reduction treatments is a major ongoing area

  16. Plant innate immunity against human bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Maeli eMelotto

    2014-08-01

    Full Text Available Certain human bacterial pathogens such as the enterohemorrhagic Escherichia coli and Salmonella enterica are not proven to be plant pathogens yet. Nonetheless, under certain conditions they can survive on, penetrate into, and colonize internal plant tissues causing serious food borne disease outbreaks. In this review, we highlight current understanding on the molecular mechanisms of plant responses against human bacterial pathogens and discuss salient common and contrasting themes of plant interactions with phytopathogens or human pathogens.

  17. Pathogen intelligence

    Directory of Open Access Journals (Sweden)

    Michael eSteinert

    2014-01-01

    Full Text Available Different species inhabit different sensory worlds and thus have evolved diverse means of processing information, learning and memory. In the escalated arms race with host defense, each pathogenic bacterium not only has evolved its individual cellular sensing and behaviour, but also collective sensing, interbacterial communication, distributed information processing, joint decision making, dissociative behaviour, and the phenotypic and genotypic heterogeneity necessary for epidemiologic success. Moreover, pathogenic populations take advantage of dormancy strategies and rapid evolutionary speed, which allow them to save co-generated intelligent traits in a collective genomic memory. This review discusses how these mechanisms add further levels of complexity to bacterial pathogenicity and transmission, and how mining for these mechanisms could help to develop new anti-infective strategies.

  18. Pathogenic agents in freshwater resources

    Science.gov (United States)

    Geldreich, Edwin E.

    1996-02-01

    Numerous pathogenic agents have been found in freshwaters used as sources for water supplies, recreational bathing and irrigation. These agents include bacterial pathogens, enteric viruses, several protozoans and parasitic worms more common to tropical waters. Although infected humans are a major source of pathogens, farm animals (cattle, sheep, pigs), animal pets (dogs, cats) and wildlife serve as significant reservoirs and should not be ignored. The range of infected individuals within a given warm-blooded animal group (humans included) may range from 1 to 25%. Survival times for pathogens in the water environment may range from a few days to as much as a year (Ascaris, Taenia eggs), with infective dose levels varying from one viable cell for several primary pathogenic agents to many thousands of cells for a given opportunistic pathogen.As pathogen detection in water is complex and not readily incorporated into routine monitoring, a surrogate is necessary. In general, indicators of faecal contamination provide a positive correlation with intestinal pathogen occurrences only when appropriate sample volumes are examined by sensitive methodology.Pathways by which pathogens reach susceptible water users include ingestion of contaminated water, body contact with polluted recreational waters and consumption of salad crops irrigated by polluted freshwaters. Major contributors to the spread of various water-borne pathogens are sewage, polluted surface waters and stormwater runoff. All of these contributions are intensified during periods of major floods. Several water-borne case histories are cited as examples of breakdowns in public health protection related to water supply, recreational waters and the consumption of contaminated salad crops. In the long term, water resource management must focus on pollution prevention from point sources of waste discharges and the spread of pathogens in watershed stormwater runoff.

  19. Modelling survival

    DEFF Research Database (Denmark)

    Ashauer, Roman; Albert, Carlo; Augustine, Starrlight

    2016-01-01

    The General Unified Threshold model for Survival (GUTS) integrates previously published toxicokinetic-toxicodynamic models and estimates survival with explicitly defined assumptions. Importantly, GUTS accounts for time-variable exposure to the stressor. We performed three studies to test...

  20. Survival analysis

    International Nuclear Information System (INIS)

    Badwe, R.A.

    1999-01-01

    The primary endpoint in the majority of the studies has been either disease recurrence or death. This kind of analysis requires a special method since all patients in the study experience the endpoint. The standard method for estimating such survival distribution is Kaplan Meier method. The survival function is defined as the proportion of individuals who survive beyond certain time. Multi-variate comparison for survival has been carried out with Cox's proportional hazard model

  1. Foodborne pathogens

    Directory of Open Access Journals (Sweden)

    Thomas Bintsis

    2017-06-01

    Full Text Available Foodborne pathogens are causing a great number of diseases with significant effects on human health and economy. The characteristics of the most common pathogenic bacteria (Bacillus cereus, Campylobacter jejuni, Clostridium botulinum, Clostridium perfringens, Cronobacter sakazakii, Esherichia coli, Listeria monocytogenes, Salmonella spp., Shigella spp., Staphylococccus aureus, Vibrio spp. and Yersinia enterocolitica, viruses (Hepatitis A and Noroviruses and parasites (Cyclospora cayetanensis, Toxoplasma gondii and Trichinella spiralis, together with some important outbreaks, are reviewed. Food safety management systems based on to classical hazard-based approach has been proved to be inefficient, and risk-based food safety approach is now suggested from leading researchers and organizations. In this context, a food safety management system should be designed in a way to estimate the risks to human health from food consumption and to identify, select and implement mitigation strategies in order to control and reduce these risks. In addition, the application of suitable food safety education programs for all involved people in the production and consumption of foods is suggested.

  2. Future research needs involving pathogens in groundwater

    Science.gov (United States)

    Bradford, Scott A.; Harvey, Ronald W.

    2017-01-01

    Contamination of groundwater by enteric pathogens has commonly been associated with disease outbreaks. Proper management and treatment of pathogen sources are important prerequisites for preventing groundwater contamination. However, non-point sources of pathogen contamination are frequently difficult to identify, and existing approaches for pathogen detection are costly and only provide semi-quantitative information. Microbial indicators that are readily quantified often do not correlate with the presence of pathogens. Pathogens of emerging concern and increasing detections of antibiotic resistance among bacterial pathogens in groundwater are topics of growing concern. Adequate removal of pathogens during soil passage is therefore critical for safe groundwater extraction. Processes that enhance pathogen transport (e.g., high velocity zones and preferential flow) and diminish pathogen removal (e.g., reversible retention and enhanced survival) are of special concern because they increase the risk of groundwater contamination, but are still incompletely understood. Improved theory and modeling tools are needed to analyze experimental data, test hypotheses, understand coupled processes and controlling mechanisms, predict spatial and/or temporal variability in model parameters and uncertainty in pathogen concentrations, assess risk, and develop mitigation and best management approaches to protect groundwater.

  3. Future research needs involving pathogens in groundwater

    Science.gov (United States)

    Bradford, Scott A.; Harvey, Ronald W.

    2017-06-01

    Contamination of groundwater by enteric pathogens has commonly been associated with disease outbreaks. Proper management and treatment of pathogen sources are important prerequisites for preventing groundwater contamination. However, non-point sources of pathogen contamination are frequently difficult to identify, and existing approaches for pathogen detection are costly and only provide semi-quantitative information. Microbial indicators that are readily quantified often do not correlate with the presence of pathogens. Pathogens of emerging concern and increasing detections of antibiotic resistance among bacterial pathogens in groundwater are topics of growing concern. Adequate removal of pathogens during soil passage is therefore critical for safe groundwater extraction. Processes that enhance pathogen transport (e.g., high velocity zones and preferential flow) and diminish pathogen removal (e.g., reversible retention and enhanced survival) are of special concern because they increase the risk of groundwater contamination, but are still incompletely understood. Improved theory and modeling tools are needed to analyze experimental data, test hypotheses, understand coupled processes and controlling mechanisms, predict spatial and/or temporal variability in model parameters and uncertainty in pathogen concentrations, assess risk, and develop mitigation and best management approaches to protect groundwater.

  4. Influence of surface polysaccharides of Escherichia coli O157:H7 on plant defense response and survival of the human enteric pathogen on Arabidopsis thaliana and lettuce (Lactuca sativa).

    Science.gov (United States)

    Jang, Hyein; Matthews, Karl R

    2018-04-01

    This study aimed to determine the influence of bacterial surface polysaccharides (cellulose, colanic acid, and lipopolysaccharide; LPS) on the colonization or survival of Escherichia coli O157:H7 on plants and the plant defense response. Survival of E. coli O157:H7 were evaluated on Arabidopsis thaliana and romaine lettuce as a model plant and an edible crop (leafy vegetable), respectively. The population of the wild-type strain of E. coli O157:H7 on Arabidopsis plants and lettuce was significantly (P lettuce regardless of day post-inoculation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Use of a continuous culture fermentation system to investigate the effect of GanedenBC30 (Bacillus coagulans GBI-30, 6086) supplementation on pathogen survival in the human gut microbiota.

    Science.gov (United States)

    Honda, Harue; Gibson, Glenn R; Farmer, Sean; Keller, David; McCartney, Anne L

    2011-02-01

    Single-stage continuous fermentation systems were employed to examine the effects of GanedenBC(30) supplementation on the human gastrointestinal microbiota in relation to pathogen challenge in vitro. Denaturing gradient gel electrophoresis analysis demonstrated that GanedenBC(30) supplementation modified the microbial profiles in the fermentation systems compared with controls, with profiles clustering according to treatment. Overall, GanedenBC(30) supplementation did not elicit major changes in bacterial population counts in vitro, although notably higher Bcoa191 counts were seen following probiotic supplementation (compared to the controls). Pathogen challenge did not elicit significant modification of the microbial counts in vitro, although notably higher Clit135 counts were seen in the control system post-Clostridium difficile challenge than in the corresponding GanedenBC(30)-supplemented systems. Sporulation appears to be associated with the anti-microbial activity of GanedenBC(30), suggesting that a bi-modal lifecycle of GanedenBC(30)in vivo may lead to anti-microbial activity in distal regions of the gastrointestinal tract. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Emerging Pathogens Initiative (EPI)

    Data.gov (United States)

    Department of Veterans Affairs — The Emerging Pathogens Initiative (EPI) database contains emerging pathogens information from the local Veterans Affairs Medical Centers (VAMCs). The EPI software...

  7. Heme Synthesis and Acquisition in Bacterial Pathogens.

    Science.gov (United States)

    Choby, Jacob E; Skaar, Eric P

    2016-08-28

    Bacterial pathogens require the iron-containing cofactor heme to cause disease. Heme is essential to the function of hemoproteins, which are involved in energy generation by the electron transport chain, detoxification of host immune effectors, and other processes. During infection, bacterial pathogens must synthesize heme or acquire heme from the host; however, host heme is sequestered in high-affinity hemoproteins. Pathogens have evolved elaborate strategies to acquire heme from host sources, particularly hemoglobin, and both heme acquisition and synthesis are important for pathogenesis. Paradoxically, excess heme is toxic to bacteria and pathogens must rely on heme detoxification strategies. Heme is a key nutrient in the struggle for survival between host and pathogen, and its study has offered significant insight into the molecular mechanisms of bacterial pathogenesis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Survival Analysis

    CERN Document Server

    Miller, Rupert G

    2011-01-01

    A concise summary of the statistical methods used in the analysis of survival data with censoring. Emphasizes recently developed nonparametric techniques. Outlines methods in detail and illustrates them with actual data. Discusses the theory behind each method. Includes numerous worked problems and numerical exercises.

  9. Comparative genome analysis of pathogenic and non-pathogenic Clavibacter strains reveals adaptations to their lifestyle.

    Science.gov (United States)

    Załuga, Joanna; Stragier, Pieter; Baeyen, Steve; Haegeman, Annelies; Van Vaerenbergh, Johan; Maes, Martine; De Vos, Paul

    2014-05-22

    The genus Clavibacter harbors economically important plant pathogens infecting agricultural crops such as potato and tomato. Although the vast majority of Clavibacter strains are pathogenic, there is an increasing number of non-pathogenic isolates reported. Non-pathogenic Clavibacter strains isolated from tomato seeds are particularly problematic because they affect the current detection and identification tests for Clavibacter michiganensis subsp. michiganensis (Cmm), which is regulated with a zero tolerance in tomato seed. Their misidentification as pathogenic Cmm hampers a clear judgment on the seed quality and health. To get more insight in the genetic features linked to the lifestyle of these bacteria, a whole-genome sequence of the tomato seed-borne non-pathogenic Clavibacter LMG 26808 was determined. To gain a better understanding of the molecular determinants of pathogenicity, the genome sequence of LMG 26808 was compared with that of the pathogenic Cmm strain (NCPPB 382). The comparative analysis revealed that LMG 26808 does not contain plasmids pCM1 and pCM2 and also lacks the majority of important virulence factors described so far for pathogenic Cmm. This explains its apparent non-pathogenic nature in tomato plants. Moreover, the genome analysis of LMG 26808 detected sequences from a plasmid originating from a member of Enterobacteriaceae/Klebsiella relative. Genes received that way and coding for antibiotic resistance may provide a competitive advantage for survival of LMG 26808 in its ecological niche. Genetically, LMG 26808 was the most similar to the pathogenic Cmm NCPPB 382 but contained more mobile genetic elements. The genome of this non-pathogenic Clavibacter strain contained also a high number of transporters and regulatory genes. The genome sequence of the non-pathogenic Clavibacter strain LMG 26808 and the comparative analyses with other pathogenic Clavibacter strains provided a better understanding of the genetic bases of virulence and

  10. Carp erythrodermatitis : host defense-pathogen interaction

    NARCIS (Netherlands)

    Pourreau, C.N.

    1990-01-01

    The outcome of a bacterial infection depends on the interaction between pathogen and host. The ability of the microbe to survive in the host depends on its invasive potential (i.e. spreading and multiplication), and its ability to obtain essential nutrients and to resist the

  11. Targeting of the hydrophobic metabolome by pathogens.

    Science.gov (United States)

    Helms, J Bernd; Kaloyanova, Dora V; Strating, Jeroen R P; van Hellemond, Jaap J; van der Schaar, Hilde M; Tielens, Aloysius G M; van Kuppeveld, Frank J M; Brouwers, Jos F

    2015-05-01

    The hydrophobic molecules of the metabolome - also named the lipidome - constitute a major part of the entire metabolome. Novel technologies show the existence of a staggering number of individual lipid species, the biological functions of which are, with the exception of only a few lipid species, unknown. Much can be learned from pathogens that have evolved to take advantage of the complexity of the lipidome to escape the immune system of the host organism and to allow their survival and replication. Different types of pathogens target different lipids as shown in interaction maps, allowing visualization of differences between different types of pathogens. Bacterial and viral pathogens target predominantly structural and signaling lipids to alter the cellular phenotype of the host cell. Fungal and parasitic pathogens have complex lipidomes themselves and target predominantly the release of polyunsaturated fatty acids from the host cell lipidome, resulting in the generation of eicosanoids by either the host cell or the pathogen. Thus, whereas viruses and bacteria induce predominantly alterations in lipid metabolites at the host cell level, eukaryotic pathogens focus on interference with lipid metabolites affecting systemic inflammatory reactions that are part of the immune system. A better understanding of the interplay between host-pathogen interactions will not only help elucidate the fundamental role of lipid species in cellular physiology, but will also aid in the generation of novel therapeutic drugs. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. The survival of Coxiella burnetii in soils

    Science.gov (United States)

    Evstigneeva, A. S.; Ul'Yanova, T. Yu.; Tarasevich, I. V.

    2007-05-01

    Coxiella burnetii is a pathogen of Q-fever—a widespread zoonosis. The effective adaptation of C. burnetii to intracellular existence is in contrast with its ability to survive in the environment outside the host cells and its resistance to chemical and physical agents. Its mechanism of survival remains unknown. However, its survival appears to be related to the developmental cycle of the microorganism itself, i.e., to the formation of its dormant forms. The survival of Coxiella burnetii was studied for the first time. The pathogenic microorganism was inoculated into different types of soil and cultivated under different temperatures. The survival of the pathogen was verified using a model with laboratory animals (mice). Viable C. burnetii were found in the soil even 20 days after their inoculation. The relationship between the organic carbon content in the soils and the survival of C. burnetii was revealed. Thus, the results obtained were the first to demonstrate that the soil may serve as a reservoir for the preservation and further spreading of the Q-fever pathogen in the environment, on the one hand, and reduce the risk of epidemics, on the other.

  13. MicroRNA profiling of the bovine alveolar macrophage response to Mycobacterium bovis infection suggests pathogen survival is enhanced by microRNA regulation of endocytosis and lysosome trafficking.

    Science.gov (United States)

    Vegh, Peter; Magee, David A; Nalpas, Nicolas C; Bryan, Kenneth; McCabe, Matthew S; Browne, John A; Conlon, Kevin M; Gordon, Stephen V; Bradley, Daniel G; MacHugh, David E; Lynn, David J

    2015-01-01

    Mycobacterium bovis, the causative agent of bovine tuberculosis, a major problem for global agriculture, spreads via an airborne route and is taken up by alveolar macrophages (AM) in the lung. Here, we describe the first next-generation sequencing (RNA-seq) approach to temporally profile miRNA expression in primary bovine AMs post-infection with M. bovis. One, six, and forty miRNAs were identified as significantly differentially expressed at 2, 24 and 48 h post-infection, respectively. The differential expression of three miRNAs (bta-miR-142-5p, bta-miR-146a, and bta-miR-423-3p) was confirmed by RT-qPCR. Pathway analysis of the predicted mRNA targets of differentially expressed miRNAs suggests that these miRNAs preferentially target several pathways that are functionally relevant for mycobacterial pathogenesis, including endocytosis and lysosome trafficking, IL-1 signalling and the TGF-β pathway. Over-expression studies using a bovine macrophage cell-line (Bomac) reveal the targeting of two key genes in the innate immune response to M. bovis, IL-1 receptor-associated kinase 1 (IRAK1) and TGF-β receptor 2 (TGFBR2), by miR-146. Taken together, our study suggests that miRNAs play a key role in tuning the complex interplay between M. bovis survival strategies and the host immune response.

  14. Neonatal intensive care unit: Reservoirs of Nosocomial pathogens ...

    African Journals Online (AJOL)

    Improvement in the care and treatment of neonates had contributed to their increased survival. Nosocomial infection remains an important problem in intensive care units. Hospital wards had been shown to act as reservoirs of pathogenic microorganisms associated with infection. To assess the prevalence of pathogenic ...

  15. Insight of Genus Corynebacterium: Ascertaining the Role of Pathogenic and Non-pathogenic Species.

    Science.gov (United States)

    Oliveira, Alberto; Oliveira, Leticia C; Aburjaile, Flavia; Benevides, Leandro; Tiwari, Sandeep; Jamal, Syed B; Silva, Arthur; Figueiredo, Henrique C P; Ghosh, Preetam; Portela, Ricardo W; De Carvalho Azevedo, Vasco A; Wattam, Alice R

    2017-01-01

    This review gathers recent information about genomic and transcriptomic studies in the Corynebacterium genus, exploring, for example, prediction of pathogenicity islands and stress response in different pathogenic and non-pathogenic species. In addition, is described several phylogeny studies to Corynebacterium , exploring since the identification of species until biological speciation in one species belonging to the genus Corynebacterium . Important concepts associated with virulence highlighting the role of Pld protein and Tox gene. The adhesion, characteristic of virulence factor, was described using the sortase mechanism that is associated to anchorage to the cell wall. In addition, survival inside the host cell and some diseases, were too addressed for pathogenic corynebacteria, while important biochemical pathways and biotechnological applications retain the focus of this review for non-pathogenic corynebacteria. Concluding, this review broadly explores characteristics in genus Corynebacterium showing to have strong relevance inside the medical, veterinary, and biotechnology field.

  16. Immune Evasion Strategies of Pathogens in Macrophages: the Potential for Limiting Pathogen Transmission.

    Science.gov (United States)

    Ren, Yuwei; Khan, Faheem Ahmed; Pandupuspitasari, Nuruliarizki Shinta; Zhang, Shujun

    2017-01-01

    Preventing pathogen transmission to a new host is of major interest to the immunologist and could benefit from a detailed investigation of pathogen immune evasion strategies. The first line of defense against pathogen invasion is provided by macrophages. When they sense pathogens, macrophages initiate signals to inflammatory and pro-inflammatory cytokines through pattern recognition receptors (PRRs) subsequently mediating phagocytosis and inflammation. The macrophage immune machinery classically includes two subsets: the activated M1 and the activated M2 that respond accordingly in diverse immune challenges. The lipid and glycogen metabolic pathways work together with the lysosome to help the mature phagosome to degrade and eliminate intracellular pathogens in macrophages. The viral evasion strategies are even more complex due to the interplay between autophagy and apoptosis. However, pathogens evolve several strategies to camouflage themselves against immune responses in order to ensure their survival, replication and transmission. These strategies include the muting of PRRs initiated inflammatory responses, attenuation of M1 and/or induction of M2 macrophages, suppression of autophago-lysosomal formation, interference with lipid and glycogen metabolism, and viral mediation of autophagy and apoptosis cross-talk to enhance viral replication. This review focuses on pathogen immune evasion methods and on the strategies used by the host against camouflaged pathogens.

  17. Surviving Sengstaken.

    Science.gov (United States)

    Jayakumar, S; Odulaja, A; Patel, S; Davenport, M; Ade-Ajayi, N

    2015-07-01

    To report the outcomes of children who underwent Sengstaken-Blakemore tube (SBT) insertion for life-threatening haemetemesis. Single institution retrospective review (1997-2012) of children managed with SBT insertion. Patient demographics, diagnosis and outcomes were noted. Data are expressed as median (range). 19 children [10 male, age 1 (0.4-16) yr] were identified; 18 had gastro-oesophageal varices and 1 aorto-oesophageal fistula. Varices were secondary to: biliary atresia (n=8), portal vein thrombosis (n=5), alpha-1-anti-trypsin deficiency (n=1), cystic fibrosis (n=1), intrahepatic cholestasis (n=1), sclerosing cholangitis (n=1) and nodular hyperplasia with arterio-portal shunt (n=1). Three children deteriorated rapidly and did not survive to have post-SBT endoscopy. The child with an aortooesophageal fistula underwent aortic stent insertion and subsequently oesophageal replacement. Complications included gastric mucosal ulceration (n=3, 16%), pressure necrosis at lips and cheeks (n=6, 31%) and SBT dislodgment (n=1, 6%). Six (31%) children died. The remaining 13 have been followed up for 62 (2-165) months; five required liver transplantation, two underwent a mesocaval shunt procedure and 6 have completed endoscopic variceal obliteration and are under surveillance. SBT can be an effective, albeit temporary, life-saving manoeuvre in children with catastrophic haematemesis. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Compatible solutes: the key to Listeria's success as a versatile gastrointestinal pathogen?

    LENUS (Irish Health Repository)

    Sleator, Roy D

    2010-12-10

    Abstract Recently we reported a role for compatible solute uptake in mediating bile tolerance and increased gastrointestinal persistence in the foodborne pathogen Listeria monocytogenes 1 . Herein, we review the evolution in our understanding of how these low molecular weight molecules contribute to growth and survival of the pathogen both inside and outside the body, and how this stress survival mechanism may ultimately be used to target and kill the pathogen.

  19. COXIELLA BURNETII PATHOGENICITY MOLECULAR BASIS

    Directory of Open Access Journals (Sweden)

    Yu. A. Panferova

    2016-01-01

    Full Text Available Coxiella burnetii is an obligate intracellular gram-negative bacterial pathogen, an ethiological agent of Q-fever, a zoonotic disease, elapsing as an acute (mostly atypical pneumonia or a chronic (mostly endocarditis form. The host range is represented by wide range of mammal, avian and arthropod species, but the main source of human infection are farm animals. The main route of infection is aerosolic. In case of contact with organism pathogen binds with phagocytal monocytic-macrophagal cell line. C. burnetii promotes maturation of specific phagolysosome-like compartment in host cell, called coxiella-containing vacuole, within this vacuole pathogen becames metabolically activated and actively replicates. Coxiella persists as metabolically inactive spore-like form in environment. Internalisation of C. burnetii occurs using actin-mediated phagocytosis and zipper mechanism. After internalization of bacteria maturation of phagolysosome-like compartment and large coxiella-containing vacuole formation occure, and vacuole can occupy nearly the whole cytoplasm of the host cell. Survivance of infected cells is important for chronic infection with C. burnetii. C. burnetii elongate the viability of host cell by two ways: it actively inhibits apoptotic signal cascades and induce pro-survival factors. Exceptthat C. burnetii involves autophagic pathway during coxiella-containing vacuole formation, and induction of autophagy promotes pathogen replication. During infection C. burnetii translocates effector substrates from bacterial cytosole to euca ryotic host cell cytosole using type IV secretion system, where effectors modulate host cell proteins. Overall approximately 130 secreted effectors of type IV transport system, but function of most of them remains unknown to date. Specific sec reted proteins for variety of strains and isolates were identified, confirmed that certain pathotypes of C. burnetii can exist. Identification and

  20. Carp erythrodermatitis : host defense-pathogen interaction

    OpenAIRE

    Pourreau, C.N.

    1990-01-01

    The outcome of a bacterial infection depends on the interaction between pathogen and host. The ability of the microbe to survive in the host depends on its invasive potential (i.e. spreading and multiplication), and its ability to obtain essential nutrients and to resist the host's defense system. On the other hand, the host's resistance to a bacterial attack depends on its physiological state, the intensity of the bacterial attack and the efficacy of the defense system to ...

  1. Potatoes, pathogens and pests

    NARCIS (Netherlands)

    Lazebnik, Jenny

    2017-01-01

    Currently, fungicides are necessary to protect potato crops against late blight, Phytophthora infestans, one of the world’s most damaging crop pathogens. The introgression of plant resistance genes from wild potato species targeted specifically to the late blight pathogen into

  2. Food-borne pathogens

    International Nuclear Information System (INIS)

    Niemand, J.G.

    1985-01-01

    The Salmonella scare reinforced the importance of never taking chances when it comes to controlling pathogens. The issue has been resolved by radurisation. The article deals with the various pathogens that can effect food and argues the case for radurisation in dealing with them. It also looks at some of the other food products that can be treated using this process

  3. Processes for managing pathogens.

    Science.gov (United States)

    Godfree, Alan; Farrell, Joseph

    2005-01-01

    Wastewater contains human, animal, and plant pathogens capable of causing viral, bacterial, or parasitic infections. There are several routes whereby sewage pathogens may affect human health, including direct contact, contamination of food crops, zoonoses, and vectors. The range and numbers of pathogens in municipal wastewater vary with the level of endemic disease in the community, discharges from commercial activities, and seasonal factors. Regulations to control pathogen risk in the United States and Europe arising from land application of biosolids are based on the concept of multiple barriers to the prevention of transmission. The barriers are (i) treatment to reduce pathogen content and vector attraction, (ii) restrictions on crops grown on land to which biosolids have been applied, and (iii) minimum intervals following application and grazing or harvesting. Wastewater treatment reduces number of pathogens in the wastewater by concentrating them with the solids in the sludge. Although some treatment processes are designed specifically to inactivate pathogens, many are not, and the actual mechanisms of microbial inactivation are not fully understood for all processes. Vector attraction is reduced by stabilization (reduction of readily biodegradable material) and/or incorporation immediately following application. Concerns about health risks have renewed interest in the effects of treatment (on pathogens) and advanced treatment methods, and work performed in the United States suggests that Class A pathogen reduction can be achieved less expensively than previously thought. Effective pathogen risk management requires control to the complete chain of sludge treatment, biosolids handling and application, and post-application activities. This may be achieved by adherence to quality management systems based on hazard analysis critical control point (HACCP) principles.

  4. Summer survival of Phytophthora ramorum in California bay laurel leaves

    Science.gov (United States)

    Elizabeth J. Fichtner; David M. Rizzo; Shannon C. Lynch; Jennifer Davidson; Gerri Buckles; Jennifer Parker

    2008-01-01

    Sudden oak death manifests as non-lethal foliar lesions on bay laurel (Umbellularia californica), which support sporulation and survival of Phytophthora ramorum in forest ecosystems. Infected bay laurel leaves are more likely to abscise than uninfected leaves, resulting in an accumulation of inoculum at the forest floor. The pathogen survives the dry...

  5. Complement Evasion by Pathogenic Leptospira.

    Science.gov (United States)

    Fraga, Tatiana Rodrigues; Isaac, Lourdes; Barbosa, Angela Silva

    2016-01-01

    Leptospirosis is a neglected infectious disease caused by spirochetes from the genus Leptospira . Pathogenic microorganisms, notably those which reach the blood circulation such as Leptospira , have evolved multiple strategies to escape the host complement system, which is important for innate and acquired immunity. Leptospira avoid complement-mediated killing through: (i) recruitment of host complement regulators; (ii) acquisition of host proteases that cleave complement proteins on the bacterial surface; and, (iii) secretion of proteases that inactivate complement proteins in the Leptospira surroundings. The recruitment of host soluble complement regulatory proteins includes the acquisition of Factor H (FH) and FH-like-1 (alternative pathway), C4b-binding protein (C4BP) (classical and lectin pathways), and vitronectin (Vn) (terminal pathway). Once bound to the leptospiral surface, FH and C4BP retain cofactor activity of Factor I in the cleavage of C3b and C4b, respectively. Vn acquisition by leptospires may result in terminal pathway inhibition by blocking C9 polymerization. The second evasion mechanism lies in plasminogen (PLG) binding to the leptospiral surface. In the presence of host activators, PLG is converted to enzymatically active plasmin, which is able to degrade C3b, C4b, and C5 at the surface of the pathogen. A third strategy used by leptospires to escape from complement system is the active secretion of proteases. Pathogenic, but not saprophytic leptospires, are able to secrete metalloproteases that cleave C3 (central complement molecule), Factor B (alternative pathway), and C4 and C2 (classical and lectin pathways). The purpose of this review is to fully explore these complement evasion mechanisms, which act together to favor Leptospira survival and multiplication in the host.

  6. Extended Storage of Pathogen-Reduced Platelet Concentrates (PRECON)

    Science.gov (United States)

    2017-12-01

    transfusion. Our project proposes to determine the efficacy of using a pathogen inactivation technique (Mirasol) coupled with a platelet additive solution (PAS...technology, platelet additive solution, platelet recovery and survival, platelet storage, platelet storage solution, platelets, thrombocytopenia, transfusion...Platelets Report to 2017 Military Health System Research Symposium ……………………………………………………………….. 29 Extended Storage of Pathogen-Reduced Platelet Concentrates

  7. Extracts against Various Pathogens

    Directory of Open Access Journals (Sweden)

    Ritika Chauhan

    2013-07-01

    The present study shows that tested lichen Parmotrema sp. extracts demonstrated a strong antimicrobial effect. That suggests the active components from methanol extracts of the investigated lichen Parmotrema sp. can be used as natural antimicrobial agent against pathogens.

  8. Evolution of microbial pathogens

    National Research Council Canada - National Science Library

    DiRita, Victor J; Seifert, H. Steven

    2006-01-01

    ... A. Hogan vvi ■ CONTENTS 8. Evolution of Pathogens in Soil Rachel Muir and Man-Wah Tan / 131 9. Experimental Models of Symbiotic Host-Microbial Relationships: Understanding the Underpinnings of ...

  9. Indicators for waterborne pathogens

    National Research Council Canada - National Science Library

    Committee on Indicators for Waterborne Pathogens, National Research Council

    2004-01-01

    ... not practical or feasible to monitor for the complete spectrum of microorganisms that may occur in water, and many known pathogens are difficult to detect directly and reliably in water samples.Â...

  10. Host–Pathogen Interactions

    NARCIS (Netherlands)

    Smits, M.A.; Schokker, D.J.

    2011-01-01

    The outcome of an infection is determined by numerous interactions between hosts and pathogens occurring at many different biological levels, ranging from molecule to population. To develop new control strategies for infectious diseases in livestock species, appropriate methodologies are needed

  11. Persistence of Pathogenic and Non-Pathogenic Escherichia coli Strains in Various Tropical Agricultural Soils of India.

    Directory of Open Access Journals (Sweden)

    S Naganandhini

    Full Text Available The persistence of Shiga-like toxin producing E. coli (STEC strains in the agricultural soil creates serious threat to human health through fresh vegetables growing on them. However, the survival of STEC strains in Indian tropical soils is not yet understood thoroughly. Additionally how the survival of STEC strain in soil diverges with non-pathogenic and genetically modified E. coli strains is also not yet assessed. Hence in the present study, the survival pattern of STEC strain (O157-TNAU was compared with non-pathogenic (MTCC433 and genetically modified (DH5α strains on different tropical agricultural soils and on a vegetable growing medium, cocopeat under controlled condition. The survival pattern clearly discriminated DH5α from MTCC433 and O157-TNAU, which had shorter life (40 days than those compared (60 days. Similarly, among the soils assessed, the red laterite and tropical latosol supported longer survival of O157-TNAU and MTCC433 as compared to wetland and black cotton soils. In cocopeat, O157 recorded significantly longer survival than other two strains. The survival data were successfully analyzed using Double-Weibull model and the modeling parameters were correlated with soil physico-chemical and biological properties using principal component analysis (PCA. The PCA of all the three strains revealed that pH, microbial biomass carbon, dehydrogenase activity and available N and P contents of the soil decided the survival of E. coli strains in those soils and cocopeat. The present research work suggests that the survival of O157 differs in tropical Indian soils due to varied physico-chemical and biological properties and the survival is much shorter than those reported in temperate soils. As the survival pattern of non-pathogenic strain, MTCC433 is similar to O157-TNAU in tropical soils, the former can be used as safe model organism for open field studies.

  12. Lipids in host-pathogen interactions: pathogens exploit the complexity of the host cell lipidome.

    Science.gov (United States)

    van der Meer-Janssen, Ynske P M; van Galen, Josse; Batenburg, Joseph J; Helms, J Bernd

    2010-01-01

    Lipids were long believed to have a structural role in biomembranes and a role in energy storage utilizing cellular lipid droplets and plasma lipoproteins. Research over the last decades has identified an additional role of lipids in cellular signaling, membrane microdomain organization and dynamics, and membrane trafficking. These properties make lipids an attractive target for pathogens to modulate host cell processes in order to allow their survival and replication. In this review we will summarize the often ingenious strategies of pathogens to modify the lipid homeostasis of host cells, allowing them to divert cellular processes. To this end pathogens take full advantage of the complexity of the lipidome. The examples are categorized in generalized and emerging principles describing the involvement of lipids in host-pathogen interactions. Several pathogens are described that simultaneously induce multiple changes in the host cell signaling and trafficking mechanisms. Elucidation of these pathogen-induced changes may have important implications for drug development. The emergence of high-throughput lipidomic techniques will allow the description of changes of the host cell lipidome at the level of individual molecular lipid species and the identification of lipid biomarkers.

  13. Sobrevivência de fungos fitopatogênicos habitantes do solo, em microcosmo, simulando solarização com prévia incorporação de materiais orgânicos Survival of soilborne plant pathogenic fungi in soil solarization simulation (microcosm associated with the incorporation of organic materials

    Directory of Open Access Journals (Sweden)

    Márcia Michelle de Queiroz Ambrósio

    2009-02-01

    Full Text Available Os fungos fitopatogênicos habitantes do solo podem sobreviver por vários anos nesse ambiente por meio de estruturas de resistência, causando perdas em muitas culturas, por vezes, inviabilizando o pleno aproveitamento de vastas áreas agrícolas. O uso de materiais orgânicos no solo consorciado com a técnica de solarização propicia a retenção de compostos voláteis fungitóxicos emanados da rápida degradação dos materiais e que são letais a vários fitopatógenos. O objetivo deste experimento foi à prospecção de novos materiais orgânicos que produzissem voláteis fungitóxicos capazes de controlar fungos fitopatogênicos habitantes do solo, em condições de associação com a simulação da técnica de solarização (microcosmo. Portanto, o presente trabalho consistiu de seis tratamentos (Solarizado; Solarizado+Brócolos; Solarizado+Eucalipto; Solarizado+Mamona; Solarizado+Mandioca e Laboratório e cinco períodos (0, 7, 14, 21 e 28 dias para avaliar a sobrevivência de quatro fungos de solo (Fusarium oxysporum f. sp. lycopersici Raça 2; Macrophomina phaseolina; Rhizoctonia solani AG-4 HGI e Sclerotium rolfsii. Em cada uma das duas câmaras de vidro (microcosmo por dia avaliado continha uma bolsa de náilon contendo as estruturas de resistência de cada fitopatógeno. Estruturas dos fitopatógenos foram mantidas também em condições de laboratório como referencial de controle. Todos os materiais quando associados à simulação da solarização propiciaram o controle de todos os fitopatógenos estudados, entretanto, foi observado variação no controle dos fungos. O tratamento que apenas simulou a solarização não controlou nenhum fitopatógeno.Soilborne phytopathogenic fungi can survive for several years in Laboratory and five periods (0, 7, 14, 21 and 28 days to evaluate soil through resistance structures and it causes losses in several crops the survival of four soil fungi (Fusarium oxysporum f. sp. lycopersici making

  14. Survival and chlamydospore production of Phytophthora ramorum in California bay laurel leaves

    Science.gov (United States)

    E. Fichtner; D. Rizzo; S. Lynch; D. Rizzo; G. Buckles; J. Parke

    2009-01-01

    Sudden oak death manifests as non-lethal foliar lesions on bay laurel (Umbellularia californica), which support sporulation and survival of Phytophthora ramorum in forest ecosystems. The pathogen survives the dry summers in a proportion of attached bay leaves, but the propagules responsible for survival are...

  15. Bacterial pathogens in a reactor cooling reservoir

    International Nuclear Information System (INIS)

    Kasweck, K.L.; Fliermans, C.B.

    1978-01-01

    The results of the sampling in both Par Pond and Clark Hill Reservoir are given. The frequency of isolation is a qualitative parameter which indicates how often the specified bacterium was isolated from each habitat. Initial scoping experiments demonstrated that a wider variety of pathogenic bacteria occur in Par Pond than in Clark Hill Reservoir. Such findings are interesting because Par Pond does not receive any human wastes directly, yet bacteria generally associated with human wastes are more frequently isolated from Par Pond. Previous studies have demonstrated that certain non-spore-forming enteric bacteria do not survive the intense heat associated with the cooling water when the reactor is operating. However, even when the reactor is not operating, cooling water, consisting of 10% makeup water from Savannah River, continues to flow into Par Pond. This flow provides a source of bacteria which inoculate Par Pond. Once the reactor is again operating, these same bacteria appear to be able to survive and grow within the Par Pond system. Thus, Par Pond and the associated lakes and canals of the Par Pond system provide a pool of pathogens that normally would not survive in natural waters

  16. Viral pathogen discovery

    Science.gov (United States)

    Chiu, Charles Y

    2015-01-01

    Viral pathogen discovery is of critical importance to clinical microbiology, infectious diseases, and public health. Genomic approaches for pathogen discovery, including consensus polymerase chain reaction (PCR), microarrays, and unbiased next-generation sequencing (NGS), have the capacity to comprehensively identify novel microbes present in clinical samples. Although numerous challenges remain to be addressed, including the bioinformatics analysis and interpretation of large datasets, these technologies have been successful in rapidly identifying emerging outbreak threats, screening vaccines and other biological products for microbial contamination, and discovering novel viruses associated with both acute and chronic illnesses. Downstream studies such as genome assembly, epidemiologic screening, and a culture system or animal model of infection are necessary to establish an association of a candidate pathogen with disease. PMID:23725672

  17. Highly pathogenic avian influenza.

    Science.gov (United States)

    Swayne, D E; Suarez, D L

    2000-08-01

    Highly pathogenic (HP) avian influenza (AI) (HPAI) is an extremely contagious, multi-organ systemic disease of poultry leading to high mortality, and caused by some H5 and H7 subtypes of type A influenza virus, family Orthomyxoviridae. However, most AI virus strains are mildly pathogenic (MP) and produce either subclinical infections or respiratory and/or reproductive diseases in a variety of domestic and wild bird species. Highly pathogenic avian influenza is a List A disease of the Office International des Epizooties, while MPAI is neither a List A nor List B disease. Eighteen outbreaks of HPAI have been documented since the identification of AI virus as the cause of fowl plague in 1955. Mildly pathogenic avian influenza viruses are maintained in wild aquatic bird reservoirs, occasionally crossing over to domestic poultry and causing outbreaks of mild disease. Highly pathogenic avian influenza viruses do not have a recognised wild bird reservoir, but can occasionally be isolated from wild birds during outbreaks in domestic poultry. Highly pathogenic avian influenza viruses have been documented to arise from MPAI viruses through mutations in the haemagglutinin surface protein. Prevention of exposure to the virus and eradication are the accepted methods for dealing with HPAI. Control programmes, which imply allowing a low incidence of infection, are not an acceptable method for managing HPAI, but have been used during some outbreaks of MPAI. The components of a strategy to deal with MPAI or HPAI include surveillance and diagnosis, biosecurity, education, quarantine and depopulation. Vaccination has been used in some control and eradication programmes for AI.

  18. Pathogenic human viruses in coastal waters

    Science.gov (United States)

    Griffin, Dale W.; Donaldson, Kim A.; Paul, J.H.; Rose, Joan B.

    2003-01-01

    This review addresses both historical and recent investigations into viral contamination of marine waters. With the relatively recent emergence of molecular biology-based assays, a number of investigations have shown that pathogenic viruses are prevalent in marine waters being impacted by sewage. Research has shown that this group of fecal-oral viral pathogens (enteroviruses, hepatitis A viruses, Norwalk viruses, reoviruses, adenoviruses, rotaviruses, etc.) can cause a broad range of asymptomatic to severe gastrointestinal, respiratory, and eye, nose, ear, and skin infections in people exposed through recreational use of the water. The viruses and the nucleic acid signature survive for an extended period in the marine environment. One of the primary concerns of public health officials is the relationship between the presence of pathogens and the recreational risk to human health in polluted marine environments. While a number of studies have attempted to address this issue, the relationship is still poorly understood. A contributing factor to our lack of progress in the field has been the lack of sensitive methods to detect the broad range of both bacterial and viral pathogens. The application of new and advanced molecular methods will continue to contribute to our current state of knowledge in this emerging and

  19. Pathogenicity of bloodstream and cerebrospinal fluid forms of ...

    African Journals Online (AJOL)

    kemrilib

    brain barrier and invade the central nervous system (CNS). However, it is not clear whether bloodstream forms (BSF) of T.b.rhodesiense differ in biological characteristics from ... carried out to compare the pathogenicity of CSF and BSF of T.b. rhodesiense parasites in ..... Swiss white of the same sex, the difference in survival ...

  20. Pathogenic potential of Listeria monocytogenes isolated from cattle ...

    African Journals Online (AJOL)

    Listeria monocytogenes is an opportunistic food-borne pathogen causing listeriosis especially among immune-compromised persons. Its high rate of morbidity and mortality has classed the organism among the top watch list in foods. It is known to produce several virulence factors which aid its survival in harsh conditions ...

  1. Human pathogen avoidance adaptations

    NARCIS (Netherlands)

    Tybur, J.M.; Lieberman, D.

    2016-01-01

    Over the past few decades, researchers have become increasingly interested in the adaptations guiding the avoidance of disease-causing organisms. Here we discuss the latest developments in this area, including a recently developed information-processing model of the adaptations underlying pathogen

  2. Survival pathways under stress

    Indian Academy of Sciences (India)

    First page Back Continue Last page Graphics. Survival pathways under stress. Bacteria survive by changing gene expression. pattern. Three important pathways will be discussed: Stringent response. Quorum sensing. Proteins performing function to control oxidative damage.

  3. Autophagy in plant pathogenic fungi.

    Science.gov (United States)

    Liu, Xiao-Hong; Xu, Fei; Snyder, John Hugh; Shi, Huan-Bin; Lu, Jian-Ping; Lin, Fu-Cheng

    2016-09-01

    Autophagy is a conserved cellular process that degrades cytoplasmic constituents in vacuoles. Plant pathogenic fungi develop special infection structures and/or secrete a range of enzymes to invade their plant hosts. It has been demonstrated that monitoring autophagy processes can be extremely useful in visualizing the sequence of events leading to pathogenicity of plant pathogenic fungi. In this review, we introduce the molecular mechanisms involved in autophagy. In addition, we explore the relationship between autophagy and pathogenicity in plant pathogenic fungi. Finally, we discuss the various experimental strategies available for use in the study of autophagy in plant pathogenic fungi. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Pathogens Use and Abuse MicroRNAs to Deceive the Immune System

    NARCIS (Netherlands)

    Flór, Thomas B.; Blom, Bianca

    2016-01-01

    Emerging evidence has demonstrated that microRNAs (miRs) play a role in the survival and amplification of viruses, bacteria and other pathogens. There are various ways in which pathogens can benefit from miR-directed alterations in protein translation and signal transduction. Members of the

  5. Plant defenses against parasitic plants show similarities to those induced by herbivores and pathogens

    Science.gov (United States)

    Justin B. Runyon; Mark C. Mescher; Consuelo M. De Moraes

    2010-01-01

    Herbivores and pathogens come quickly to mind when one thinks of the biotic challenges faced by plants. Important but less appreciated enemies are parasitic plants, which can have important consequences for the fitness and survival of their hosts. Our knowledge of plant perception, signaling and response to herbivores and pathogens has expanded rapidly in recent years...

  6. Pathogenic mechanisms of intracellular bacteria.

    Science.gov (United States)

    Niller, Hans Helmut; Masa, Roland; Venkei, Annamária; Mészáros, Sándor; Minarovits, Janos

    2017-06-01

    We wished to overview recent data on a subset of epigenetic changes elicited by intracellular bacteria in human cells. Reprogramming the gene expression pattern of various host cells may facilitate bacterial growth, survival, and spread. DNA-(cytosine C5)-methyltransferases of Mycoplasma hyorhinis targeting cytosine-phosphate-guanine (CpG) dinucleotides and a Mycobacterium tuberculosis methyltransferase targeting non-CpG sites methylated the host cell DNA and altered the pattern of gene expression. Gene silencing by CpG methylation and histone deacetylation, mediated by cellular enzymes, also occurred in M. tuberculosis-infected macrophages. M. tuberculosis elicited cell type-specific epigenetic changes: it caused increased DNA methylation in macrophages, but induced demethylation, deposition of euchromatic histone marks and activation of immune-related genes in dendritic cells. A secreted transposase of Acinetobacter baumannii silenced a cellular gene, whereas Mycobacterium leprae altered the epigenotype, phenotype, and fate of infected Schwann cells. The 'keystone pathogen' oral bacterium Porphyromonas gingivalis induced local DNA methylation and increased the level of histone acetylation in host cells. These epigenetic changes at the biofilm-gingiva interface may contribute to the development of periodontitis. Epigenetic regulators produced by intracellular bacteria alter the epigenotype and gene expression pattern of host cells and play an important role in pathogenesis.

  7. Exploring NAD+ metabolism in host-pathogen interactions.

    Science.gov (United States)

    Mesquita, Inês; Varela, Patrícia; Belinha, Ana; Gaifem, Joana; Laforge, Mireille; Vergnes, Baptiste; Estaquier, Jérôme; Silvestre, Ricardo

    2016-03-01

    Nicotinamide adenine dinucleotide (NAD(+)) is a vital molecule found in all living cells. NAD(+) intracellular levels are dictated by its synthesis, using the de novo and/or salvage pathway, and through its catabolic use as co-enzyme or co-substrate. The regulation of NAD(+) metabolism has proven to be an adequate drug target for several diseases, including cancer, neurodegenerative or inflammatory diseases. Increasing interest has been given to NAD(+) metabolism during innate and adaptive immune responses suggesting that its modulation could also be relevant during host-pathogen interactions. While the maintenance of NAD(+) homeostatic levels assures an adequate environment for host cell survival and proliferation, fluctuations in NAD(+) or biosynthetic precursors bioavailability have been described during host-pathogen interactions, which will interfere with pathogen persistence or clearance. Here, we review the double-edged sword of NAD(+) metabolism during host-pathogen interactions emphasizing its potential for treatment of infectious diseases.

  8. Adult trees cause density-dependent mortality in conspecific seedlings by regulating the frequency of pathogenic soil fungi.

    Science.gov (United States)

    Liang, Minxia; Liu, Xubing; Gilbert, Gregory S; Zheng, Yi; Luo, Shan; Huang, Fengmin; Yu, Shixiao

    2016-12-01

    Negative density-dependent seedling mortality has been widely detected in tropical, subtropical and temperate forests, with soil pathogens as a major driver. Here we investigated how host density affects the composition of soil pathogen communities and consequently influences the strength of plant-soil feedbacks. In field censuses of six 1-ha permanent plots, we found that survival was much lower for newly germinated seedlings that were surrounded by more conspecific adults. The relative abundance of pathogenic fungi in soil increased with increasing conspecific tree density for five of nine tree species; more soil pathogens accumulated around roots where adult tree density was higher, and this greater pathogen frequency was associated with lower seedling survival. Our findings show how tree density influences populations of soil pathogens, which creates plant-soil feedbacks that contribute to community-level and population-level compensatory trends in seedling survival. © 2016 John Wiley & Sons Ltd/CNRS.

  9. Evolution of microbial pathogens.

    OpenAIRE

    Morschhäuser, J; Köhler, G; Ziebuhr, W; Blum-Oehler, G; Dobrindt, U; Hacker, J

    2000-01-01

    Various genetic mechanisms including point mutations, genetic rearrangements and lateral gene transfer processes contribute to the evolution of microbes. Long-term processes leading to the development of new species or subspecies are termed macroevolution, and short-term developments, which occur during days or weeks, are considered as microevolution. Both processes, macro- and microevolution need horizontal gene transfer, which is particularly important for the development of pathogenic micr...

  10. Survival and Virulence of Campylobacter spp. in the Environment

    DEFF Research Database (Denmark)

    Bui, Thanh Xuan

    of environmental stress factors, namely heat shock, starvation, osmosis, and oxidation, on the expression of three virulence genes (ciaB, dnaJ, and htrA) of C. jejuni and its uptake by and intracellular survival within A. castellanii. I also investigated the mechanism(s) involved in phagocytosis and killing of C....... jejuni by A. castellanii. I observed that heat and osmotic stresses reduced the survival of C. jejuni significantly, whereas oxidative stress had no effect. The results of qRT-PCR experiments showed that the transcription of virulence genes of C. jejuni was slightly up-regulated under heat and oxidative...... soil flagellates may play a role for the survival of these food-borne pathogens on plant surfaces and in soil. It would be very interesting to further investigate the impacts of this soil flagellate on the survival of different food-borne pathogens in soil and in plant surface that may explain...

  11. Network survivability performance

    Science.gov (United States)

    1993-11-01

    This technical report has been developed to address the survivability of telecommunications networks including services. It responds to the need for a common understanding of, and assessment techniques for network survivability, availability, integrity, and reliability. It provides a basis for designing and operating telecommunications networks to user expectations for network survivability and a foundation for continuing industry activities in the subject area. This report focuses on the survivability of both public and private networks and covers a wide range of users. Two frameworks are established for quantifying and categorizing service outages, and for classifying network survivability techniques and measures. The performance of the network survivability techniques is considered; however, recommended objectives are not established for network survivability performance.

  12. AMP-activated Protein Kinase As a Target For Pathogens: Friends Or Foes?

    Science.gov (United States)

    Moreira, Diana; Silvestre, Ricardo; Cordeiro-da-Silva, Anabela; Estaquier, Jérôme; Foretz, Marc; Viollet, Benoit

    2016-01-01

    Intracellular pathogens are known to manipulate host cell regulatory pathways to establish an optimal environment for their growth and survival. Pathogens employ active mechanisms to hijack host cell metabolism and acquire existing nutrient and energy store. The role of the cellular energy sensor AMP-activated protein kinase (AMPK) in the regulation of cellular energy homeostasis is well documented. Here, we highlight recent advances showing the importance of AMPK signaling in pathogen-host interactions. Pathogens interact with AMPK by a variety of mechanisms aimed at reprogramming host cell metabolism to their own benefit. Stimulation of AMPK activity provides an efficient process to rapidly adapt pathogen metabolism to the major nutritional changes often encountered during the different phases of infection. However, inhibition of AMPK is also used by pathogens to manipulate innate host response, indicating that AMPK appears relevant to restriction of pathogen infection. We also document the effects of pharmacological AMPK modulators on pathogen proliferation and survival. This review illustrates intricate pathogen-AMPK interactions that may be exploited to the development of novel anti-pathogen therapies.

  13. Clostridium difficile is an autotrophic bacterial pathogen.

    Directory of Open Access Journals (Sweden)

    Michael Köpke

    Full Text Available During the last decade, Clostridium difficile infection showed a dramatic increase in incidence and virulence in the Northern hemisphere. This incessantly challenging disease is the leading cause of antibiotic-associated and nosocomial infectious diarrhea and became life-threatening especially among elderly people. It is generally assumed that all human bacterial pathogens are heterotrophic organisms, being either saccharolytic or proteolytic. So far, this has not been questioned as colonization of the human gut gives access to an environment, rich in organic nutrients. Here, we present data that C. difficile (both clinical and rumen isolates is also able to grow on CO2+H2 as sole carbon and energy source, thus representing the first identified autotrophic bacterial pathogen. Comparison of several different strains revealed high conservation of genes for autotrophic growth and showed that the ability to use gas mixtures for growth decreases or is lost upon prolonged culturing under heterotrophic conditions. The metabolic flexibility of C. difficile (heterotrophic growth on various substrates as well as autotrophy could allow the organism in the gut to avoid competition by niche differentiation and contribute to its survival when stressed or in unfavorable conditions that cause death to other bacteria. This may be an important trait for the pathogenicity of C. difficile.

  14. Host-pathogen interplay of Haemophilus ducreyi.

    Science.gov (United States)

    Janowicz, Diane M; Li, Wei; Bauer, Margaret E

    2010-02-01

    Haemophilus ducreyi, the causative agent of the sexually transmitted infection chancroid, is primarily a pathogen of human skin. During infection, H. ducreyi thrives extracellularly in a milieu of professional phagocytes and other antibacterial components of the innate and adaptive immune responses. This review summarizes our understanding of the interplay between this pathogen and its host that leads to development and persistence of disease. H. ducreyi expresses key virulence mechanisms to resist host defenses. The secreted LspA proteins are tyrosine-phosphorylated by host kinases, which may contribute to their antiphagocytic effector function. The serum resistance and adherence functions of DsrA map to separate domains of this multifunctional virulence factor. An influx transporter protects H. ducreyi from killing by the antimicrobial peptide LL37. Regulatory genes have been identified that may coordinate virulence factor expression during disease. Dendritic cells and natural killer cells respond to H. ducreyi and may be involved in determining the differential outcomes of infection observed in humans. A human model of H. ducreyi infection has provided insights into virulence mechanisms that allow this human-specific pathogen to survive immune pressures. Components of the human innate immune system may also determine the ultimate fate of H. ducreyi infection by driving either clearance of the organism or an ineffective response that allows disease progression.

  15. Combinatorial stresses kill pathogenic Candida species

    Science.gov (United States)

    Kaloriti, Despoina; Tillmann, Anna; Cook, Emily; Jacobsen, Mette; You, Tao; Lenardon, Megan; Ames, Lauren; Barahona, Mauricio; Chandrasekaran, Komelapriya; Coghill, George; Goodman, Daniel; Gow, Neil A. R.; Grebogi, Celso; Ho, Hsueh-Lui; Ingram, Piers; McDonagh, Andrew; De Moura, Alessandro P. S.; Pang, Wei; Puttnam, Melanie; Radmaneshfar, Elahe; Romano, Maria Carmen; Silk, Daniel; Stark, Jaroslav; Stumpf, Michael; Thiel, Marco; Thorne, Thomas; Usher, Jane; Yin, Zhikang; Haynes, Ken; Brown, Alistair J. P.

    2012-01-01

    Pathogenic microbes exist in dynamic niches and have evolved robust adaptive responses to promote survival in their hosts. The major fungal pathogens of humans, Candida albicans and Candida glabrata, are exposed to a range of environmental stresses in their hosts including osmotic, oxidative and nitrosative stresses. Significant efforts have been devoted to the characterization of the adaptive responses to each of these stresses. In the wild, cells are frequently exposed simultaneously to combinations of these stresses and yet the effects of such combinatorial stresses have not been explored. We have developed a common experimental platform to facilitate the comparison of combinatorial stress responses in C. glabrata and C. albicans. This platform is based on the growth of cells in buffered rich medium at 30°C, and was used to define relatively low, medium and high doses of osmotic (NaCl), oxidative (H 2O2) and nitrosative stresses (e.g., dipropylenetriamine (DPTA)-NONOate). The effects of combinatorial stresses were compared with the corresponding individual stresses under these growth conditions. We show for the first time that certain combinations of combinatorial stress are especially potent in terms of their ability to kill C. albicans and C. glabrata and/or inhibit their growth. This was the case for combinations of osmotic plus oxidative stress and for oxidative plus nitrosative stress. We predict that combinatorial stresses may be highly signif cant in host defences against these pathogenic yeasts. PMID:22463109

  16. Multinationals and plant survival

    DEFF Research Database (Denmark)

    Bandick, Roger

    2010-01-01

    The aim of this paper is twofold: first, to investigate how different ownership structures affect plant survival, and second, to analyze how the presence of foreign multinational enterprises (MNEs) affects domestic plants’ survival. Using a unique and detailed data set on the Swedish manufacturing...... sector, I am able to separate plants into those owned by foreign MNEs, domestic MNEs, exporting non-MNEs, and purely domestic firms. In line with previous findings, the result, when conditioned on other factors affecting survival, shows that foreign MNE plants have lower survival rates than non......-MNE plants. However, separating the non-MNEs into exporters and non-exporters, the result shows that foreign MNE plants have higher survival rates than non-exporting non-MNEs, while the survival rates of foreign MNE plants and exporting non-MNE plants do not seem to differ. Moreover, the simple non...

  17. Urbanization Increases Pathogen Pressure on Feral and Managed Honey Bees.

    Directory of Open Access Journals (Sweden)

    Elsa Youngsteadt

    Full Text Available Given the role of infectious disease in global pollinator decline, there is a need to understand factors that shape pathogen susceptibility and transmission in bees. Here we ask how urbanization affects the immune response and pathogen load of feral and managed colonies of honey bees (Apis mellifera Linnaeus, the predominant economically important pollinator worldwide. Using quantitative real-time PCR, we measured expression of 4 immune genes and relative abundance of 10 honey bee pathogens. We also measured worker survival in a laboratory bioassay. We found that pathogen pressure on honey bees increased with urbanization and management, and the probability of worker survival declined 3-fold along our urbanization gradient. The effect of management on pathogens appears to be mediated by immunity, with feral bees expressing immune genes at nearly twice the levels of managed bees following an immune challenge. The effect of urbanization, however, was not linked with immunity; instead, urbanization may favor viability and transmission of some disease agents. Feral colonies, with lower disease burdens and stronger immune responses, may illuminate ways to improve honey bee management. The previously unexamined effects of urbanization on honey-bee disease are concerning, suggesting that urban areas may favor problematic diseases of pollinators.

  18. Urbanization Increases Pathogen Pressure on Feral and Managed Honey Bees.

    Science.gov (United States)

    Youngsteadt, Elsa; Appler, R Holden; López-Uribe, Margarita M; Tarpy, David R; Frank, Steven D

    2015-01-01

    Given the role of infectious disease in global pollinator decline, there is a need to understand factors that shape pathogen susceptibility and transmission in bees. Here we ask how urbanization affects the immune response and pathogen load of feral and managed colonies of honey bees (Apis mellifera Linnaeus), the predominant economically important pollinator worldwide. Using quantitative real-time PCR, we measured expression of 4 immune genes and relative abundance of 10 honey bee pathogens. We also measured worker survival in a laboratory bioassay. We found that pathogen pressure on honey bees increased with urbanization and management, and the probability of worker survival declined 3-fold along our urbanization gradient. The effect of management on pathogens appears to be mediated by immunity, with feral bees expressing immune genes at nearly twice the levels of managed bees following an immune challenge. The effect of urbanization, however, was not linked with immunity; instead, urbanization may favor viability and transmission of some disease agents. Feral colonies, with lower disease burdens and stronger immune responses, may illuminate ways to improve honey bee management. The previously unexamined effects of urbanization on honey-bee disease are concerning, suggesting that urban areas may favor problematic diseases of pollinators.

  19. Survival of Salmonella Newport in oysters.

    Science.gov (United States)

    Morrison, Christopher M; Armstrong, Alexandra E; Evans, Sanford; Mild, Rita M; Langdon, Christopher J; Joens, Lynn A

    2011-08-02

    Salmonella enterica is the leading cause of laboratory-confirmed foodborne illness in the United States and raw shellfish consumption is a commonly implicated source of gastrointestinal pathogens. A 2005 epidemiological study done in our laboratory by Brands et al., showed that oysters in the United States are contaminated with Salmonella, and in particular, a specific strain of the Newport serovar. This work sought to further investigate the host-microbe interactions between Salmonella Newport and oysters. A procedure was developed to reliably and repeatedly expose oysters to enteric bacteria and quantify the subsequent levels of bacterial survival. The results show that 10 days after an exposure to Salmonella Newport, an average concentration of 3.7 × 10(3)CFU/g remains within the oyster meat, and even after 60 days there still can be more than 10(2)CFU/g remaining. However, the strain of Newport that predominated in the market survey done by Brands et al. does not survive within oysters or the estuarine environment better than any other strains of Salmonella we tested. Using this same methodology, we compared Salmonella Newport's ability to survive within oysters to a non-pathogenic strain of E. coli and found that after 10 days the concentration of Salmonella was 200-times greater than that of E. coli. We also compared those same strains of Salmonella and E. coli in a depuration process to determine if a constant 120 L/h flux of clean seawater could significantly reduce the concentration of bacteria within oysters and found that after 3 days the oysters retained over 10(4)CFU/g of Salmonella while the oysters exposed to the non-pathogenic strain of E. coli contained 100-times less bacteria. Overall, the results of this study demonstrate that any of the clinically relevant serovars of Salmonella can survive within oysters for significant periods of time after just one exposure event. Based on the drastic differences in survivability between Salmonella and a non-pathogenic

  20. RecA: a universal drug target in pathogenic bacteria.

    Science.gov (United States)

    Pavlopoulou, Athanasia

    2018-01-01

    The spread of bacterial infectious diseases due to the development of resistance to antibiotic drugs in pathogenic bacteria is an emerging global concern. Therefore, the efficacious management and prevention of bacterial infections are major public health challenges. RecA is a pleiotropic recombinase protein that has been demonstrated to be implicated strongly in the bacterial drug resistance, survival and pathogenicity. In this minireview, RecA's role in the development of antibiotic resistance and its potential as an antimicrobial drug target are discussed.

  1. Autophagic clearance of bacterial pathogens: molecular recognition of intracellular microorganisms.

    Science.gov (United States)

    Pareja, Maria Eugenia Mansilla; Colombo, Maria I

    2013-01-01

    Autophagy is involved in several physiological and pathological processes. One of the key roles of the autophagic pathway is to participate in the first line of defense against the invasion of pathogens, as part of the innate immune response. Targeting of intracellular bacteria by the autophagic machinery, either in the cytoplasm or within vacuolar compartments, helps to control bacterial proliferation in the host cell, controlling also the spreading of the infection. In this review we will describe the means used by diverse bacterial pathogens to survive intracellularly and how they are recognized by the autophagic molecular machinery, as well as the mechanisms used to avoid autophagic clearance.

  2. Ortholog-based screening and identification of genes related to intracellular survival.

    Science.gov (United States)

    Yang, Xiaowen; Wang, Jiawei; Bing, Guoxia; Bie, Pengfei; De, Yanyan; Lyu, Yanli; Wu, Qingmin

    2018-04-20

    Bioinformatics and comparative genomics analysis methods were used to predict unknown pathogen genes based on homology with identified or functionally clustered genes. In this study, the genes of common pathogens were analyzed to screen and identify genes associated with intracellular survival through sequence similarity, phylogenetic tree analysis and the λ-Red recombination system test method. The total 38,952 protein-coding genes of common pathogens were divided into 19,775 clusters. As demonstrated through a COG analysis, information storage and processing genes might play an important role intracellular survival. Only 19 clusters were present in facultative intracellular pathogens, and not all were present in extracellular pathogens. Construction of a phylogenetic tree selected 18 of these 19 clusters. Comparisons with the DEG database and previous research revealed that seven other clusters are considered essential gene clusters and that seven other clusters are associated with intracellular survival. Moreover, this study confirmed that clusters screened by orthologs with similar function could be replaced with an approved uvrY gene and its orthologs, and the results revealed that the usg gene is associated with intracellular survival. The study improves the current understanding of intracellular pathogens characteristics and allows further exploration of the intracellular survival-related gene modules in these pathogens. Copyright © 2018. Published by Elsevier B.V.

  3. Manipulation of host membranes by the bacterial pathogens Listeria, Francisella, Shigella and Yersinia.

    Science.gov (United States)

    Pizarro-Cerdá, Javier; Charbit, Alain; Enninga, Jost; Lafont, Frank; Cossart, Pascale

    2016-12-01

    Bacterial pathogens display an impressive arsenal of molecular mechanisms that allow survival in diverse host niches. Subversion of plasma membrane and cytoskeletal functions are common themes associated to infection by both extracellular and intracellular pathogens. Moreover, intracellular pathogens modify the structure/stability of their membrane-bound compartments and escape degradation from phagocytic or autophagic pathways. Here, we review the manipulation of host membranes by Listeria monocytogenes, Francisella tularensis, Shigella flexneri and Yersinia spp. These four bacterial model pathogens exemplify generalized strategies as well as specific features observed during bacterial infection processes. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. Impact of climate trends on tick-borne pathogen transmission

    Directory of Open Access Journals (Sweden)

    Agustin eEstrada-Pena

    2012-03-01

    Full Text Available Recent advances in climate research together with a better understanding of tick-pathogen interactions, the distribution of ticks and the diagnosis of tick-borne pathogens raise questions about the impact of environmental factors on tick abundance and spread and the prevalence and transmission of tick-borne pathogens. While undoubtedly climate plays a role in the changes in distribution and seasonal abundance of ticks, it is always difficult to disentangle factors impacting on the abundance of tick hosts from those exerted by human habits. All together, climate, host abundance and social factors may explain the upsurge of epidemics transmitted by ticks to humans. Herein we focused on tick-borne pathogens that affect humans with pandemic potential. Borrelia burgdorferi s.l. (Lyme disease, Anaplasma phagocytophilum (human granulocytic anaplasmosis and tick-borne encephalitis virus (tick-borne encephalitis are transmitted by Ixodes spp. Crimean-Congo hemorrhagic fever virus (Crimean-Congo hemorrhagic fever is transmitted by Hyalomma spp. In this review, we discussed how vector tick species occupy the habitat as a function of different climatic factors, and how these factors impact on tick survival and seasonality. How molecular events at the tick-pathogen interface impact on pathogen transmission is also discussed. Results from statistically and biologically derived models are compared to show that while statistical models are able to outline basic information about tick distributions, biologically derived models are necessary to evaluate pathogen transmission rates and understand the effect of climatic variables and host abundance patterns on pathogen transmission. The results of these studies could be used to build early alert systems able to identify the main factors driving the subtle changes in tick distribution and seasonality and the prevalence of tick-borne pathogens.

  5. Survival strategies of Listeria monocytogenes - roles of regulators and transporters

    NARCIS (Netherlands)

    Wemekamp-Kamphuis, H.H.

    2003-01-01

    Outbreaks of the food-borne pathogen Listeria monocytogenes are mainly associated with ready-to-eatfoods. Survival strategies of L. monocytogenes in relation to minimally processed foods were studied.

  6. Mechanical transmission and survival of bacterial wilt on enset ...

    African Journals Online (AJOL)

    The transmission of enset bacterial wilt with contaminated knives and the survival of the causal agent in soil and enset plant debris was studied at the Awassa Agricultural Research Center, Awassa, Ethiopia. Contaminated knives were found to transmit the pathogen from infected to healthy plants. Disease symptoms were ...

  7. ASURV: Astronomical SURVival Statistics

    Science.gov (United States)

    Feigelson, E. D.; Nelson, P. I.; Isobe, T.; LaValley, M.

    2014-06-01

    ASURV (Astronomical SURVival Statistics) provides astronomy survival analysis for right- and left-censored data including the maximum-likelihood Kaplan-Meier estimator and several univariate two-sample tests, bivariate correlation measures, and linear regressions. ASURV is written in FORTRAN 77, and is stand-alone and does not call any specialized libraries.

  8. Pathogenic mycoflora on carrot seeds

    Directory of Open Access Journals (Sweden)

    Bogdan Nowicki

    2013-12-01

    Full Text Available Altogether 300 seed samples were collected during 9 years in 8 regions of Poland and the fungi Were isolated and their pathogenicity to carrot seedlings was examined. Alternaria rudicina provcd to be the most important pathogen although. A. alternata was more common. The other important pathogens were Fusarium spp., Phoma spp. and Botrytis cinerea. The infection of carrot seeds by A. radicina should be used as an important criterium in seed quality evaluation.

  9. Metabolic principles of persistence and pathogenicity in Mycobacterium tuberculosis.

    Science.gov (United States)

    Ehrt, Sabine; Schnappinger, Dirk; Rhee, Kyu Y

    2018-04-24

    Metabolism was once relegated to the supply of energy and biosynthetic precursors, but it has now become clear that it is a specific mediator of nearly all physiological processes. In the context of microbial pathogenesis, metabolism has expanded outside its canonical role in bacterial replication. Among human pathogens, this expansion has emerged perhaps nowhere more visibly than for Mycobacterium tuberculosis, the causative agent of tuberculosis. Unlike most pathogens, M. tuberculosis has evolved within humans, which are both host and reservoir. This makes unrestrained replication and perpetual quiescence equally incompatible strategies for survival as a species. In this Review, we summarize recent work that illustrates the diversity of metabolic functions that not only enable M. tuberculosis to establish and maintain a state of chronic infection within the host but also facilitate its survival in the face of drug pressure and, ultimately, completion of its life cycle.

  10. Survival of Listeria monocytogenes on a conveyor belt material with or without antimicrobial additives

    NARCIS (Netherlands)

    Chaitiemwong, N.; Hazeleger, W.C.; Beumer, R.R.

    2010-01-01

    Survival of Listeria monocytogenes on a conveyor belt material with or without antimicrobial additives, in the absence or presence of food debris from meat, fish and vegetables and at temperatures of 10, 25 and 37 °C was investigated. The pathogen survived best at 10 °C, and better at 25 °C than at

  11. Comparing Temperature Effects on E. Coli, Salmonella, and Enterococcus Survival in Surface Waters

    Science.gov (United States)

    The objective of this study was to compare dependency of survival rates on temperature for indicator organisms E. coli and Enterococcus and the pathogen Salmonella in surface waters. A database of 86 survival datasets from peer-reviewed papers on inactivation of E. coli, Salmonel...

  12. Comparative proteomic analysis of pathogenic and non-pathogenic strains from the swine pathogen Mycoplasma hyopneumoniae

    Directory of Open Access Journals (Sweden)

    Klein Cátia S

    2009-12-01

    Full Text Available Abstract Background Mycoplasma hyopneumoniae is a highly infectious swine pathogen and is the causative agent of enzootic pneumonia (EP. Following the previous report of a proteomic survey of the pathogenic 7448 strain of swine pathogen, Mycoplasma hyopneumoniae, we performed comparative protein profiling of three M. hyopneumoniae strains, namely the non-pathogenic J strain and the two pathogenic strains 7448 and 7422. Results In 2DE comparisons, we were able to identify differences in expression levels for 67 proteins, including the overexpression of some cytoadherence-related proteins only in the pathogenic strains. 2DE immunoblot analyses allowed the identification of differential proteolytic cleavage patterns of the P97 adhesin in the three strains. For more comprehensive protein profiling, an LC-MS/MS strategy was used. Overall, 35% of the M. hyopneumoniae genome coding capacity was covered. Partially overlapping profiles of identified proteins were observed in the strains with 81 proteins identified only in one strain and 54 proteins identified in two strains. Abundance analysis of proteins detected in more than one strain demonstrates the relative overexpression of 64 proteins, including the P97 adhesin in the pathogenic strains. Conclusions Our results indicate the physiological differences between the non-pathogenic strain, with its non-infective proliferate lifestyle, and the pathogenic strains, with its constitutive expression of adhesins, which would render the bacterium competent for adhesion and infection prior to host contact.

  13. Global Distribution of Two Fungal Pathogens Threatening Endangered Sea Turtles

    OpenAIRE

    Sarmiento-Ramírez, Jullie M.; Abella-Pérez, Elena; Phillott, Andrea D.; Sim, Jolene; van West, Pieter; Martín, María P.; Marco, Adolfo; Diéguez-Uribeondo, Javier

    2014-01-01

    Nascent fungal infections are currently considered as one of the main threats for biodiversity and ecosystem health, and have driven several animal species into critical risk of extinction. Sea turtles are one of the most endangered groups of animals and only seven species have survived to date. Here, we described two pathogenic species, i.e., Fusarium falciforme and Fusarium keratoplasticum, that are globally distributed in major turtle nesting areas for six sea turtle species and that are i...

  14. Network ties and survival

    DEFF Research Database (Denmark)

    Acheampong, George; Narteh, Bedman; Rand, John

    2017-01-01

    Poultry farming has been touted as one of the major ways by which poverty can be reduced in low-income economies like Ghana. Yet, anecdotally there is a high failure rate among these poultry farms. This current study seeks to understand the relationship between network ties and survival chances...... of small commercial poultry farms (SCPFs). We utilize data from a 2-year network survey of SCPFs in rural Ghana. The survival of these poultry farms are modelled using a lagged probit model of farms that persisted from 2014 into 2015. We find that network ties are important to the survival chances...... but this probability reduces as the number of industry ties increases but moderation with dynamic capability of the firm reverses this trend. Our findings show that not all network ties aid survival and therefore small commercial poultry farmers need to be circumspect in the network ties they cultivate and develop....

  15. Survival of falling robots

    Science.gov (United States)

    Cameron, Jonathan M.; Arkin, Ronald C.

    1992-01-01

    As mobile robots are used in more uncertain and dangerous environments, it will become important to design them so that they can survive falls. In this paper, we examine a number of mechanisms and strategies that animals use to withstand these potentially catastrophic events and extend them to the design of robots. A brief survey of several aspects of how common cats survive falls provides an understanding of the issues involved in preventing traumatic injury during a falling event. After outlining situations in which robots might fall, a number of factors affecting their survival are described. From this background, several robot design guidelines are derived. These include recommendations for the physical structure of the robot as well as requirements for the robot control architecture. A control architecture is proposed based on reactive control techniques and action-oriented perception that is geared to support this form of survival behavior.

  16. Survivability and Hope

    Science.gov (United States)

    ... Current Issue Past Issues Special Section Survivability and Hope Past Issues / Spring 2007 Table of Contents For ... cure or long-term survivorship." This message of hope is a hallmark of the latest advances in ...

  17. Survival of falling robots

    Science.gov (United States)

    Cameron, Jonathan M.; Arkin, Ronald C.

    1992-02-01

    As mobile robots are used in more uncertain and dangerous environments, it will become important to design them so that they can survive falls. In this paper, we examine a number of mechanisms and strategies that animals use to withstand these potentially catastrophic events and extend them to the design of robots. A brief survey of several aspects of how common cats survive falls provides an understanding of the issues involved in preventing traumatic injury during a falling event. After outlining situations in which robots might fall, a number of factors affecting their survival are described. From this background, several robot design guidelines are derived. These include recommendations for the physical structure of the robot as well as requirements for the robot control architecture. A control architecture is proposed based on reactive control techniques and action-oriented perception that is geared to support this form of survival behavior.

  18. Pathogenicity and diversity of vegetative compatibility of Fusarium verticillioides

    Directory of Open Access Journals (Sweden)

    Krnjaja Vesna S.

    2007-01-01

    Full Text Available Pathogenicity of 10 Fusarium verticillioides isolates, originated from grain of wheat (five isolates and maize (five isolates, were studied under greenhouse conditions. Based on different parameters of the pathogenicity estimate (a scale for % of nonemerged plants, % of survived plants, plant vigour - the growth and dry weight of roots and epicotyls and disease severity it was determined that all F. verticillioides isolates expressed a different degree of pathogenicity. According to % of nonemerged plants six three and one F. verticillioides isolates expressed low, moderate and high degree of pathogenicity, respectively. All F. verticillioides isolates reduced the plant survival rate and vigour, while the disease severity ranged from 2.0 to 3.54. Two types of nit mutants, nit1 and NitM, were obtained by the use of the method of vegetative compatibility. The frequency of nit1 mutants was greater (58.79% than the frequency of NitM mutants (5.77%. A total of 10 vegetative compatibility groups (VCGs of F. verticillioides were established in the complementation tests. These results point out to a high genetic diversity of F. verticillioides population.

  19. Characteristic features of intracellular pathogenic Leptospira in infected murine macrophages.

    Science.gov (United States)

    Toma, Claudia; Okura, Nobuhiko; Takayama, Chitoshi; Suzuki, Toshihiko

    2011-11-01

    Leptospira interrogans is a spirochaete responsible for a zoonotic disease known as leptospirosis. Leptospires are able to penetrate the abraded skin and mucous membranes and rapidly disseminate to target organs such as the liver, lungs and kidneys. How this pathogen escape from innate immune cells and spread to target organs remains poorly understood. In this paper, the intracellular trafficking undertaken by non-pathogenic Leptospira biflexa and pathogenic L. interrogans in mouse bone marrow-derived macrophages was compared. The delayed in the clearance of L. interrogans was observed. Furthermore, the acquisition of lysosomal markers by L. interrogans-containing phagosomes lagged behind that of L. biflexa-containing phagosomes, and although bone marrow-derived macrophages could degrade L. biflexa as well as L. interrogans, a population of L. interrogans was able to survive and replicate. Intact leptospires were found within vacuoles at 24 h post infection, suggesting that bacterial replication occurs within a membrane-bound compartment. In contrast, L. biflexa were completely degraded at 24 h post infection. Furthermore, L. interrogans but not L. biflexa, were released to the extracellular milieu. These results suggest that pathogenic leptospires are able to survive, replicate and exit from mouse macrophages, enabling their eventual spread to target organs. © 2011 Blackwell Publishing Ltd.

  20. Bacterial pathogen manipulation of host membrane trafficking.

    Science.gov (United States)

    Asrat, Seblewongel; de Jesús, Dennise A; Hempstead, Andrew D; Ramabhadran, Vinay; Isberg, Ralph R

    2014-01-01

    Pathogens use a vast number of strategies to alter host membrane dynamics. Targeting the host membrane machinery is important for the survival and pathogenesis of several extracellular, vacuolar, and cytosolic bacteria. Membrane manipulation promotes bacterial replication while suppressing host responses, allowing the bacterium to thrive in a hostile environment. This review provides a comprehensive summary of various strategies used by both extracellular and intracellular bacteria to hijack host membrane trafficking machinery. We start with mechanisms used by bacteria to alter the plasma membrane, delve into the hijacking of various vesicle trafficking pathways, and conclude by summarizing bacterial adaptation to host immune responses. Understanding bacterial manipulation of host membrane trafficking provides insights into bacterial pathogenesis and uncovers the molecular mechanisms behind various processes within a eukaryotic cell.

  1. Risk to water wells of pathogens in drilling fluids[Section 7 : reviewed literature added November 2009

    Energy Technology Data Exchange (ETDEWEB)

    Abiola, A.T. [Olds College, Olds, AB (Canada); Ryan, C. [Calgary Univ., AB (Canada)

    2009-10-15

    Public concern regarding the presence of pathogens in surface waters used in drilling fluids and their potential impact on groundwater and water wells has increased in recent years. This report addressed those concerns. The most common sources of water for drilling fluids include dugouts, sloughs, small creeks and beaver dams. The Energy Resources Conservation Board commissioned a study to examine the abundance of pathogens in surface waters and to evaluate whether pathogens in surface waters that are used in drilling fluids have the ability to survive in or be transported through groundwater. The report was written for the general public and represents a professional opinion based on an extensive review of literature and professional experience. It described the risk to well water of pathogens in drilling fluids; pathogens in well water; and fate of pathogens in drilling fluids. The key findings of the report were that the subsurface of the earth presents a hostile environment to surface water pathogens. In addition to pathogen introduction from drilling fluid, pathogens can be introduced through animal waste, sewage and industrial or agricultural waste. Typically, the types of pathogens found in Alberta surface waters are not likely to survive the salt levels found in nontoxic drilling fluids. Pathogen transport into the subsurface is unlikely, even over shorter distances, because of the low infiltration distance of drilling fluids from the wellbore. 142 refs.

  2. Comparative flight activities and pathogen load of two stocks of honey bees reared in gamma-irradiated combs

    Science.gov (United States)

    Gamma irradiation is known to inactivate various pathogens that negatively affect honey bee health. Bee pathogens such as Deformed wing virus (DWV) and Nosema spp. have deleterious impact on foraging activities and bee survival, and have been detected in combs. In this study, we assessed the effects...

  3. Planning for compliance: OSHA's bloodborne pathogen rule.

    Science.gov (United States)

    Bednar, B; Duke, M C

    1990-11-01

    Overall, the bloodborne pathogen rule constitutes a reasonable response to a significant threat to workplace safety. The risks to dialysis workers from HBV and HIV must be minimized or eliminated and the rule is generally consistent with the consensus approach. Unfortunately for dialysis providers, the rule is not exempt from the law of unintended consequences: government regulation will always have impact beyond its object. Promulgation of the final rule will immediately increase the expenses of dialysis providers. Additionally, the enormity of the HBV and HIV problem coupled with the open-ended nature of the rule's key provisions will almost certainly bring additional costs. So long as dialysis reimbursement remains flat, the unintended consequence of the bloodborne pathogen rule may be to quicken the pace of consolidation in the dialysis service market. The added burden of compliance may be too much for small independent facilities. Only large chains may have the resources to comply and survive. To forestall this effect and to provide employees with maximum protection, all dialysis providers should plan now for compliance.

  4. Microbial antagonism as a potential solution for controlling selected root pathogens of crops

    Science.gov (United States)

    Cooper, Sarah; Agnew, Linda; Pereg, Lily

    2016-04-01

    Root pathogens of crops can cause large reduction in yield, however, there is a limited range of effective methods to control such pathogens. Soilborne pathogens that infect roots often need to survive in the rhizosphere, where there is high competition from other organisms. In such hot spots of microbial activity and growth, supported by root exudates, microbes have evolved antagonistic mechanisms that give them competitive advantages in winning the limited resources. Among these mechanisms is antibiosis, with production of some significant antifungal compounds including, antibiotics, volatile organic compounds, hydrogen cyanide and lytic enzymes. Some of these mechanisms may suppress disease through controlling the growth of root pathogens. In this project we isolated various fungi and bacteria that suppress the growth of cotton pathogens in vitro. The pathogen-suppressive microbes were isolated from cotton production soils that are under different management strategies, with and without the use of organic amendments. The potential of pathogen-suppressing microbes for controlling the black root rot disease, caused by the soilborne pathogen Thielaviopsis basicola, was confirmed using soil assays. We identified isolates with potential use as inoculant for cotton production in Australia. Having isolated a diverse group of antagonistic microbes enhances the probability that some would survive well in the soil and provide an alternative approach to address the problem of root disease affecting agricultural crops.

  5. Transient virulence of emerging pathogens.

    Science.gov (United States)

    Bolker, Benjamin M; Nanda, Arjun; Shah, Dharmini

    2010-05-06

    Should emerging pathogens be unusually virulent? If so, why? Existing theories of virulence evolution based on a tradeoff between high transmission rates and long infectious periods imply that epidemic growth conditions will select for higher virulence, possibly leading to a transient peak in virulence near the beginning of an epidemic. This transient selection could lead to high virulence in emerging pathogens. Using a simple model of the epidemiological and evolutionary dynamics of emerging pathogens, along with rough estimates of parameters for pathogens such as severe acute respiratory syndrome, West Nile virus and myxomatosis, we estimated the potential magnitude and timing of such transient virulence peaks. Pathogens that are moderately evolvable, highly transmissible, and highly virulent at equilibrium could briefly double their virulence during an epidemic; thus, epidemic-phase selection could contribute significantly to the virulence of emerging pathogens. In order to further assess the potential significance of this mechanism, we bring together data from the literature for the shapes of tradeoff curves for several pathogens (myxomatosis, HIV, and a parasite of Daphnia) and the level of genetic variation for virulence for one (myxomatosis). We discuss the need for better data on tradeoff curves and genetic variance in order to evaluate the plausibility of various scenarios of virulence evolution.

  6. Pathogenicity of Mycobacterium tuberculosis is expressed by regulating metabolic thresholds of the host macrophage.

    Directory of Open Access Journals (Sweden)

    Parul Mehrotra

    2014-07-01

    Full Text Available The success of Mycobacterium tuberculosis as a pathogen derives from its facile adaptation to the intracellular milieu of human macrophages. To explore this process, we asked whether adaptation also required interference with the metabolic machinery of the host cell. Temporal profiling of the metabolic flux, in cells infected with differently virulent mycobacterial strains, confirmed that this was indeed the case. Subsequent analysis identified the core subset of host reactions that were targeted. It also elucidated that the goal of regulation was to integrate pathways facilitating macrophage survival, with those promoting mycobacterial sustenance. Intriguingly, this synthesis then provided an axis where both host- and pathogen-derived factors converged to define determinants of pathogenicity. Consequently, whereas the requirement for macrophage survival sensitized TB susceptibility to the glycemic status of the individual, mediation by pathogen ensured that the virulence properties of the infecting strain also contributed towards the resulting pathology.

  7. Ecological niche of plant pathogens

    Directory of Open Access Journals (Sweden)

    Ecaterina Fodor

    2011-06-01

    Full Text Available Disease ecology is a new approach to the understanding of the spread and dynamics of pathogens in natural and man-made environments. Defining and describing the ecological niche of the pathogens is one of the major tasks for ecological theory, as well as for practitioners preoccupied with the control and forecasting of established and emerging diseases. Niche theory has been periodically revised, not including in an explicit way the pathogens. However, many progresses have been achieved in niche modeling of disease spread, but few attempts were made to construct a theoretical frame for the ecological niche of pathogens. The paper is a review of the knowledge accumulated during last decades in the niche theory of pathogens and proposes an ecological approach in research. It quest for new control methods in what concerns forest plant pathogens, with a special emphasis on fungi like organisms of the genus Phytophthora. Species of Phytophthora are the most successful plant pathogens of the moment, affecting forest and agricultural systems worldwide, many of them being invasive alien organisms in many ecosystems. The hyperspace of their ecological niche is defined by hosts, environment and human interference, as main axes. To select most important variables within the hyperspace, is important the understanding of the complex role of pathogens in the ecosystems as well as for control programs. Biotic relationships within ecosystem of host-pathogen couple are depicted by ecological network and specific metrics attached to this. The star shaped network is characterized by few high degree nodes, by short path lengths and relatively low connectivity, premises for a rapid disturbance spread. 

  8. Ecological niche of plant pathogens

    Directory of Open Access Journals (Sweden)

    Ecaterina Fodor

    2011-02-01

    Full Text Available Disease ecology is a new approach to the understanding of the spread and dynamics of pathogens in natural and man-made environments. Defining and describing the ecological niche of the pathogens is one of the major tasks for ecological theory, as well as for practitioners preoccupied with the control and forecasting of established and emerging diseases. Niche theory has been periodically revised, not including in an explicit way the pathogens. However, many progresses have been achieved in niche modeling of disease spread, but few attempts were made to construct a theoretical frame for the ecological niche of pathogens. The paper is a review of the knowledge accumulated during last decades in the niche theory of pathogens and proposes an ecological approach in research. It quest for new control methods in what concerns forest plant pathogens, with a special emphasis on fungi like organisms of the genus Phytophthora. Species of Phytophthora are the most successful plant pathogens of the moment, affecting forest and agricultural systems worldwide, many of them being invasive alien organisms in many ecosystems. The hyperspace of their ecological niche is defined by hosts, environment and human interference, as main axes. To select most important variables within the hyperspace, is important for the understanding of the complex role of pathogens in the ecosystems as well as for control programs. Biotic relationships within ecosystem of host-pathogen couple are depicted by ecological network and specific metrics attached to this. The star shaped network is characterized by few high degree nodes, by short path lengths and relatively low connectivity, premises for a rapid disturbance spread.

  9. Fate of pathogenic Bacillus cereus spores after ingestion by protist grazers

    DEFF Research Database (Denmark)

    Winding, Anne; Santos, Susana; Hendriksen, Niels Bohse

    The aim of this study is to understand the symbiosis between bacterivorous protists and pathogenic bacterial spores, in order to gain insight on survival and dispersal of pathogenic bacteria in the environment. It is generally accepted that resistance to grazing by protists has contributed...... to the evolution of Bacillus cereus group bacteria (e.g. B. cereus, B. anthracis, B. thuringiensis) as a pathogen. It has been hypothesized that the spore stage protects against digestion by predating protists. Indeed, B. thuringiensis spores have been shown to be readily ingested by ciliated protists but failed...... to be digested (Manasherob et al 1998 AEM 64:1750-). Here we report how diverse protist grazers grow on both vegetative cells and spores of B. cereus and how the bacteria survive ingestion and digestion, and even proliferate inside the digestive vacuoles of ciliated protists. The survival ability of B. cereus...

  10. Host pathogen relations: exploring animal models for fungal pathogens.

    Science.gov (United States)

    Harwood, Catherine G; Rao, Reeta P

    2014-06-30

    Pathogenic fungi cause superficial infections but pose a significant public health risk when infections spread to deeper tissues, such as the lung. Within the last three decades, fungi have been identified as the leading cause of nosocomial infections making them the focus of research. This review outlines the model systems such as the mouse, zebrafish larvae, flies, and nematodes, as well as ex vivo and in vitro systems available to study common fungal pathogens.

  11. Host Pathogen Relations: Exploring Animal Models for Fungal Pathogens

    Directory of Open Access Journals (Sweden)

    Catherine G. Harwood

    2014-06-01

    Full Text Available Pathogenic fungi cause superficial infections but pose a significant public health risk when infections spread to deeper tissues, such as the lung. Within the last three decades, fungi have been identified as the leading cause of nosocomial infections making them the focus of research. This review outlines the model systems such as the mouse, zebrafish larvae, flies, and nematodes, as well as ex vivo and in vitro systems available to study common fungal pathogens.

  12. Interaction of the tick immune system with transmitted pathogens

    Directory of Open Access Journals (Sweden)

    Ondrej eHajdusek

    2013-07-01

    Full Text Available Ticks are hematophagous arachnids transmitting a wide variety of pathogens including viruses, bacteria, and protozoans to their vertebrate hosts. The tick vector competence has to be intimately linked to the ability of transmitted pathogens to evade tick defense mechanisms encountered on their route through the tick body comprising midgut, hemolymph, salivary glands or ovaries. Tick innate immunity is, like in other invertebrates, based on an orchestrated action of humoral and cellular immune responses. The direct antimicrobial defense in ticks is accomplished by a variety of small molecules such as defensins, lysozymes or by tick-specific antimicrobial compounds such as microplusin/hebraein or 5.3-kDa family proteins. Phagocytosis of the invading microbes by tick hemocytes seems to be mediated by the primordial complement-like system composed of thioester-containing proteins, fibrinogen-related lectins and convertase-like factors. Moreover, an important role in survival of the ingested microbes seems to be played by host proteins and redox balance maintenance in the tick midgut. Here, we summarize recent knowledge about the major components of tick immune system and focus on their interaction with the relevant tick-transmitted pathogens, represented by spirochetes (Borrelia, rickettsiae (Anaplasma, and protozoans (Babesia. Availability of the tick genomic database and feasibility of functional genomics based on RNA interference greatly contribute to the understanding of molecular and cellular interplay at the tick-pathogen interface and may provide new targets for blocking the transmission of tick pathogens.

  13. Comparative genomics and the evolution of pathogenicity in human pathogenic fungi.

    LENUS (Irish Health Repository)

    Moran, Gary P

    2011-01-01

    Because most fungi have evolved to be free-living in the environment and because the infections they cause are usually opportunistic in nature, it is often difficult to identify specific traits that contribute to fungal pathogenesis. In recent years, there has been a surge in the number of sequenced genomes of human fungal pathogens, and comparison of these sequences has proved to be an excellent resource for exploring commonalities and differences in how these species interact with their hosts. In order to survive in the human body, fungi must be able to adapt to new nutrient sources and environmental stresses. Therefore, genes involved in carbohydrate and amino acid metabolism and transport and genes encoding secondary metabolites tend to be overrepresented in pathogenic species (e.g., Aspergillus fumigatus). However, it is clear that human commensal yeast species such as Candida albicans have also evolved a range of specific factors that facilitate direct interaction with host tissues. The evolution of virulence across the human pathogenic fungi has occurred largely through very similar mechanisms. One of the most important mechanisms is gene duplication and the expansion of gene families, particularly in subtelomeric regions. Unlike the case for prokaryotic pathogens, horizontal transfer of genes between species and other genera does not seem to have played a significant role in the evolution of fungal virulence. New sequencing technologies promise the prospect of even greater numbers of genome sequences, facilitating the sequencing of multiple genomes and transcriptomes within individual species, and will undoubtedly contribute to a deeper insight into fungal pathogenesis.

  14. Bacteria isolated from parasitic nematodes - a potential novel vector of pathogens?

    OpenAIRE

    Lacharme-Lora, Lizeth; Salisbury, Vyv; Humphrey, Tom J.; Stafford, Kathryn; Perkins, Sarah E.

    2009-01-01

    Bacterial pathogens are ubiquitous in soil and water - concurrently so are free-living helminths that feed on bacteria. These helminths fall into two categories; the non-parasitic and the parasitic. The former have been the focus of previous work, finding that bacterial pathogens inside helminths are conferred survival advantages over and above bacteria alone in the environment, and that accidental ingestion of non-parasitic helminths can cause systemic infection in vertebrate hosts. Here, we...

  15. Potential role of bacteria packaging by protozoa in the persistence and transmission of pathogenic bacteria

    OpenAIRE

    Denoncourt, Alix M.; Paquet, Valérie E.; Charette, Steve J.

    2014-01-01

    Many pathogenic bacteria live in close association with protozoa. These unicellular eukaryotic microorganisms are ubiquitous in various environments. A number of protozoa such as amoebae and ciliates ingest pathogenic bacteria, package them usually in membrane structures, and then release them into the environment. Packaged bacteria are more resistant to various stresses and are more apt to survive than free bacteria. New evidence indicates that protozoa and not bacteria control the packaging...

  16. Genomic and Phenomic Study of Mammary Pathogenic Escherichia coli

    Science.gov (United States)

    Blum, Shlomo E.; Heller, Elimelech D.; Sela, Shlomo; Elad, Daniel; Edery, Nir; Leitner, Gabriel

    2015-01-01

    Escherichia coli is a major etiological agent of intra-mammary infections (IMI) in cows, leading to acute mastitis and causing great economic losses in dairy production worldwide. Particular strains cause persistent IMI, leading to recurrent mastitis. Virulence factors of mammary pathogenic E. coli (MPEC) involved pathogenesis of mastitis as well as those differentiating strains causing acute or persistent mastitis are largely unknown. This study aimed to identify virulence markers in MPEC through whole genome and phenome comparative analysis. MPEC strains causing acute (VL2874 and P4) or persistent (VL2732) mastitis were compared to an environmental strain (K71) and to the genomes of strains representing different E. coli pathotypes. Intra-mammary challenge in mice confirmed experimentally that the strains studied here have different pathogenic potential, and that the environmental strain K71 is non-pathogenic in the mammary gland. Analysis of whole genome sequences and predicted proteomes revealed high similarity among MPEC, whereas MPEC significantly differed from the non-mammary pathogenic strain K71, and from E. coli genomes from other pathotypes. Functional features identified in MPEC genomes and lacking in the non-mammary pathogenic strain were associated with synthesis of lipopolysaccharide and other membrane antigens, ferric-dicitrate iron acquisition and sugars metabolism. Features associated with cytotoxicity or intra-cellular survival were found specifically in the genomes of strains from severe and acute (VL2874) or persistent (VL2732) mastitis, respectively. MPEC genomes were relatively similar to strain K-12, which was subsequently shown here to be possibly pathogenic in the mammary gland. Phenome analysis showed that the persistent MPEC was the most versatile in terms of nutrients metabolized and acute MPEC the least. Among phenotypes unique to MPEC compared to the non-mammary pathogenic strain were uric acid and D-serine metabolism. This study

  17. Inactivation of bacterial pathogenic load in compost against vermicompost of organic solid waste aiming to achieve sanitation goals: A review.

    Science.gov (United States)

    Soobhany, Nuhaa; Mohee, Romeela; Garg, Vinod Kumar

    2017-06-01

    Waste management strategies for organic residues, such as composting and vermicomposting, have been implemented in some developed and developing countries to solve the problem of organic solid waste (OSW). Yet, these biological treatment technologies do not always result in good quality compost or vermicompost with regards to sanitation capacity owing to the presence of bacterial pathogenic substances in objectionable concentrations. The presence of pathogens in soil conditioners poses a potential health hazard and their occurrence is of particular significance in composts and/or vermicomposts produced from organic materials. Past and present researches demonstrated a high-degree of agreement that various pathogens survive after the composting of certain OSW but whether similar changes in bacterial pathogenic loads arise during vermitechnology has not been thoroughly elucidated. This review garners information regarding the status of various pathogenic bacteria which survived or diffused after the composting process compared to the status of these pathogens after the vermicomposting of OSW with the aim of achieving sanitation goals. This work is also indispensable for the specification of compost quality guidelines concerning pathogen loads which would be specific to treatment technology. It was hypothesized that vermicomposting process for OSW can be efficacious in sustaining the existence of pathogenic organisms most specifically; human pathogens under safety levels. In summary, earthworms can be regarded as a way of obliterating pathogenic bacteria from OSW in a manner equivalent to earthworm gut transit mechanism which classifies vermicomposting as a promising sanitation technique in comparison to composting processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Tropism and pathogenicity of rickettsiae

    Directory of Open Access Journals (Sweden)

    Tsuneo eUchiyama

    2012-06-01

    Full Text Available Rickettsiae are obligate intracellular parasitic bacteria that cause febrile exanthematous illnesses such as Rocky Mountain spotted fever, Mediterranean spotted fever, epidemic and murine typhus, etc. Although the vector ranges of each Rickettsia species are rather restricted; i.e., ticks belonging to Arachnida and lice and fleas belonging to Insecta usually act as vectors for spotted fever group and typhus group rickettsiae, respectively, it would be interesting to elucidate the mechanisms controlling the vector tropism of rickettsiae. This review discusses the factors determining the vector tropism of rickettsiae. In brief, the vector tropism of rickettsiae species is basically consistent with their tropism towards cultured tick and insect cells. The mechanisms responsible for rickettsiae pathogenicity are also described. Recently, genomic analyses of rickettsiae have revealed that they possess several genes that are homologous to those affecting the pathogenicity of other bacteria. Analyses comparing the genomes of pathogenic and nonpathogenic strains of rickettsiae have detected many factors that are related to rickettsial pathogenicity. It is also known that a reduction in the rickettsial genome has occurred during the course of its evolution. Interestingly, Rickettsia species with small genomes, such as Rickettsia prowazekii, are more pathogenic to humans than those with larger genomes. This review also examines the growth kinetics of pathogenic and nonpathogenic species of spotted fever group rickettsiae in mammalian cells. The growth of nonpathogenic species is restricted in these cells, which is mediated, at least in part, by autophagy. The superinfection of nonpathogenic rickettsiae-infected cells with pathogenic rickettsiae results in an elevated yield of the nonpathogenic rickettsiae and the growth of the pathogenic rickettsiae. Autophagy is restricted in these cells. These results are discussed in this review.

  19. Pathogen avoidance by insect predators

    OpenAIRE

    Meyling, Nicolai V.; Ormond, Emma; Roy, Helen E.; Pell, Judith K.

    2008-01-01

    Insects can detect cues related to the risk of attack by their natural enemies. Pathogens are among the natural enemies of insects and entomopathogenic fungi attack a wide array of host species. Evidence documents that social insects in particular have adapted behavioural mechanisms to avoid infection by fungal pathogens. These mechanisms are referred to as 'behavioural resistance'. However, there is little evidence for similar adaptations in non-social insects. We have conducted experime...

  20. Antibiotic Resistance in Foodborne Pathogens

    OpenAIRE

    Walsh, Ciara; Duffy, Geraldine

    2013-01-01

    Wide-spread antibiotic resistance among bacterial pathogens is now a serious public health issue and multi-antibiotic resistance has been reported in many foodborne pathogens including Salmonella and E. coli. A study to determine antibiotic resistance profiles of a range of Salmonella and Verocytotoxigenic E.coli (VTEC) isolated from Irish foods revealed significant levels of antibiotic resistance in the strains. S. typhimurium DT104 were multiantibiotic resistant with 97% resistant to 7 anti...

  1. Molecular detection of human bacterial pathogens

    National Research Council Canada - National Science Library

    Liu, Dongyou

    2011-01-01

    .... Molecular Detection of Human Bacterial Pathogens addresses this issue, with international scientists in respective bacterial pathogen research and diagnosis providing expert summaries on current...

  2. Surviving After Suicide

    Science.gov (United States)

    ... fewer tools for communicating their feelings. Surviving After Suicide Fact Sheet 3 Children are especially vulnerable to feelings of guilt and ... to take care of them. Secrecy about the suicide in the hopes of protecting children may cause further complications. Explain the situation and ...

  3. Survivability via Control Objectives

    Energy Technology Data Exchange (ETDEWEB)

    CAMPBELL,PHILIP L.

    2000-08-11

    Control objectives open an additional front in the survivability battle. A given set of control objectives is valuable if it represents good practices, it is complete (it covers all the necessary areas), and it is auditable. CobiT and BS 7799 are two examples of control objective sets.

  4. Education for Survival.

    Science.gov (United States)

    Allen, James E., Jr.

    In this address, James E. Allen, Jr., Assistant Secretary for Education and U.S. Commissioner of Education, discusses the relationship of education to the problem of ecological destruction. He states that the solutions to the problems of air, water, and soil pollution may be found in redirected education. This "education for survival" can serve to…

  5. Artists’ Survival Rate

    DEFF Research Database (Denmark)

    Bille, Trine; Jensen, Søren

    2017-01-01

    The literature of cultural economics generally finds that an artistic education has no significant impact on artists’ income and careers in the arts. In our research, we have readdressed this question by looking at the artists’ survival in the arts occupations. The results show that an artistic...... education has a significant impact on artists’ careers in the arts and we find important industry differences....

  6. Lack of the RNA chaperone Hfq attenuates pathogenicity of several Escherichia coli pathotypes towards Caenorhabditis elegans

    DEFF Research Database (Denmark)

    Bojer, Martin Saxtorph; Jakobsen, Henrik; Struve, Carsten

    2012-01-01

    as a model for virulence characterization and screening for novel antimicrobial entities. Several E. coli human pathotypes are also pathogenic towards C. elegans, and we show here that lack of the RNA chaperone Hfq significantly reduces pathogenicity of VTEC, EAEC, and UPEC in the nematode model. Thus, Hfq...... is intrinsically essential to pathogenic E. coli for survival and virulence exerted in the C. elegans host.......Escherichia coli is an important agent of Gram-negative bacterial infections worldwide, being one of the leading causes of diarrhoea and urinary tract infections. Strategies to understand pathogenesis and develop therapeutic compounds include the use of the nematode Caenorhabditis elegans...

  7. Biosensors for plant pathogen detection.

    Science.gov (United States)

    Khater, Mohga; de la Escosura-Muñiz, Alfredo; Merkoçi, Arben

    2017-07-15

    Infectious plant diseases are caused by pathogenic microorganisms such as fungi, bacteria, viruses, viroids, phytoplasma and nematodes. Worldwide, plant pathogen infections are among main factors limiting crop productivity and increasing economic losses. Plant pathogen detection is important as first step to manage a plant disease in greenhouses, field conditions and at the country boarders. Current immunological techniques used to detect pathogens in plant include enzyme-linked immunosorbent assays (ELISA) and direct tissue blot immunoassays (DTBIA). DNA-based techniques such as polymerase chain reaction (PCR), real time PCR (RT-PCR) and dot blot hybridization have also been proposed for pathogen identification and detection. However these methodologies are time-consuming and require complex instruments, being not suitable for in-situ analysis. Consequently, there is strong interest for developing new biosensing systems for early detection of plant diseases with high sensitivity and specificity at the point-of-care. In this context, we revise here the recent advancement in the development of advantageous biosensing systems for plant pathogen detection based on both antibody and DNA receptors. The use of different nanomaterials such as nanochannels and metallic nanoparticles for the development of innovative and sensitive biosensing systems for the detection of pathogens (i.e. bacteria and viruses) at the point-of-care is also shown. Plastic and paper-based platforms have been used for this purpose, offering cheap and easy-to-use really integrated sensing systems for rapid on-site detection. Beside devices developed at research and development level a brief revision of commercially available kits is also included in this review. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Radiobilogical cell survival models

    International Nuclear Information System (INIS)

    Zackrisson, B.

    1992-01-01

    A central issue in clinical radiobiological research is the prediction of responses to different radiation qualities. The choice of cell survival and dose-response model greatly influences the results. In this context the relationship between theory and model is emphasized. Generally, the interpretations of experimental data depend on the model. Cell survival models are systematized with respect to their relations to radiobiological theories of cell kill. The growing knowlegde of biological, physical, and chemical mechanisms is reflected in the formulation of new models. The present overview shows that recent modelling has been more oriented towards the stochastic fluctuations connected to radiation energy deposition. This implies that the traditional cell surivival models ought to be complemented by models of stochastic energy deposition processes and repair processes at the intracellular level. (orig.)

  9. Carbonaceous Survivability on Impact

    Science.gov (United States)

    Bunch, T. E.; Becker, Luann; Morrison, David (Technical Monitor)

    1994-01-01

    In order to gain knowledge about the potential contributions of comets and cosmic dust to the origin of life on Earth, we need to explore the survivability of their potential organic compounds on impact and the formation of secondary products that may have arisen from the chaotic events sustained by the carriers as they fell to Earth. We have performed a series of hypervelocity impact experiments using carbon-bearing impactors (diamond, graphite, kerogens, PAH crystals, and Murchison and Nogoya meteorites) into Al plate targets at velocities - 6 km/s. Estimated peak shock pressures probably did not exceed 120 GPa and peak shock temperatures were probably less than 4000 K for times of nano- to microsecs. Nominal crater dia. are less than one mm. The most significant results of these experiments are the preservation of the higher mass PAHs (e. g., pyrene relative to napthalene) and the formation of additional alkylated PAHs. We have also examined the residues of polystyrene projectiles impacted by a microparticle accelerator into targets at velocities up to 15 km/s. This talk will discuss the results of these experiments and their implications with respect to the survival of carbonaceous deliverables to early Earth. The prospects of survivability of organic molecules on "intact" capture of cosmic dust in space via soft: and hard cosmic dust collectors will also be discussed.

  10. Survival analysis models and applications

    CERN Document Server

    Liu, Xian

    2012-01-01

    Survival analysis concerns sequential occurrences of events governed by probabilistic laws.  Recent decades have witnessed many applications of survival analysis in various disciplines. This book introduces both classic survival models and theories along with newly developed techniques. Readers will learn how to perform analysis of survival data by following numerous empirical illustrations in SAS. Survival Analysis: Models and Applications: Presents basic techniques before leading onto some of the most advanced topics in survival analysis.Assumes only a minimal knowledge of SAS whilst enablin

  11. Viruses, Other Pathogenic Microorganisms and Esophageal Cancer.

    Science.gov (United States)

    Xu, Wenji; Liu, Zhongshu; Bao, Quncha; Qian, Zhikan

    2015-05-01

    Esophageal cancer (EC) is the eighth most prevalent malignant tumor and the sixth leading cause of cancer mortality throughout the world. Despite the technical developments in diagnosis and treatment, the 5-year survival rate is still low. The etiology of EC remains poorly understood; multiple risk factors may be involved and account for the great variation in EC incidence in different geographic regions. Infection with carcinogenetic pathogens has been proposed as a risk factor for EC. This review explores the recent studies on the association of human papillomavirus (HPV), Epstein-Barr virus (EBV), Helicobacter pylori and esophageal bacterial biota with EC. Among the above-mentioned pathogens, HPV most likely contributes to esophageal squamous cell carcinoma (ESCC) in high-risk populations. New techniques are being applied to studies on the role of infection in EC, which will inevitably bring novel ideas to the field in the near future. Multiple meta-analyses support the finding of a higher HPV detection rate in regions associated with high risk for ESCC compared to low-risk areas. A potential role of HPV in the rise of esophageal adenocarcinoma (EAC) was proposed recently. However, further studies are required before a firm conclusion can be drawn. Less work has been done in studying the association between EBV and ESCC, and the results are quite controversial. H. pylori infection is found to be inversely related to EC, which is probably due to the reduced incidence of gastroesophageal reflux disease. Analysis of the esophageal bacterial biota revealed distinct clusters of bacteria in normal and diseased esophagi. A type II microbiome rich in Gram-negative bacteria potentially contributes to EAC by inducing chronic inflammation. Novel findings from such studies as these may benefit public health by justifying anti-infection measures to prevent EC.

  12. Diverse microbial species survive high ammonia concentrations

    Science.gov (United States)

    Kelly, Laura C.; Cockell, Charles S.; Summers, Stephen

    2012-04-01

    Planetary protection regulations are in place to control the contamination of planets and moons with terrestrial micro-organisms in order to avoid jeopardizing future scientific investigations relating to the search for life. One environmental chemical factor of relevance in extraterrestrial environments, specifically in the moons of the outer solar system, is ammonia (NH3). Ammonia is known to be highly toxic to micro-organisms and may disrupt proton motive force, interfere with cellular redox reactions or cause an increase of cell pH. To test the survival potential of terrestrial micro-organisms exposed to such cold, ammonia-rich environments, and to judge whether current planetary protection regulations are sufficient, soil samples were exposed to concentrations of NH3 from 5 to 35% (v/v) at -80°C and room temperature for periods up to 11 months. Following exposure to 35% NH3, diverse spore-forming taxa survived, including representatives of the Firmicutes (Bacillus, Sporosarcina, Viridibacillus, Paenibacillus, Staphylococcus and Brevibacillus) and Actinobacteria (Streptomyces). Non-spore forming organisms also survived, including Proteobacteria (Pseudomonas) and Actinobacteria (Arthrobacter) that are known to have environmentally resistant resting states. Clostridium spp. were isolated from the exposed soil under anaerobic culture. High NH3 was shown to cause a reduction in viability of spores over time, but spore morphology was not visibly altered. In addition to its implications for planetary protection, these data show that a large number of bacteria, potentially including spore-forming pathogens, but also environmentally resistant non-spore-formers, can survive high ammonia concentrations.

  13. Pathogenicity of highly pathogenic avian influenza virus in mammals

    NARCIS (Netherlands)

    de Wit, Emmie; Kawaoka, Yoshihiro; de Jong, Menno D.; Fouchier, Ron A. M.

    2008-01-01

    In recent years, there has been an increase in outbreaks of highly pathogenic avian influenza (HPAI) in poultry. Occasionally, these outbreaks have resulted in transmission of influenza viruses to humans and other mammals, with symptoms ranging from conjunctivitis to pneumonia and death. Here, the

  14. From Exit to Entry: Long-term Survival and Transmission of Salmonella

    Directory of Open Access Journals (Sweden)

    Landon L. Waldner

    2012-10-01

    Full Text Available Salmonella spp. are a leading cause of human infectious disease worldwide and pose a serious health concern. While we have an improving understanding of pathogenesis and the host-pathogen interactions underlying the infection process, comparatively little is known about the survival of pathogenic Salmonella outside their hosts. This review focuses on three areas: (1 in vitro evidence that Salmonella spp. can survive for long periods of time under harsh conditions; (2 observations and conclusions about Salmonella persistence obtained from human outbreaks; and (3 new information revealed by genomic- and population-based studies of Salmonella and related enteric pathogens. We highlight the mechanisms of Salmonella persistence and transmission as an essential part of their lifecycle and a prerequisite for their evolutionary success as human pathogens.

  15. Pathogen transport in groundwater systems: contrasts with traditional solute transport

    Science.gov (United States)

    Hunt, Randall J.; Johnson, William P.

    2017-06-01

    Water quality affects many aspects of water availability, from precluding use to societal perceptions of fit-for-purpose. Pathogen source and transport processes are drivers of water quality because they have been responsible for numerous outbreaks resulting in large economic losses due to illness and, in some cases, loss of life. Outbreaks result from very small exposure (e.g., less than 20 viruses) from very strong sources (e.g., trillions of viruses shed by a single infected individual). Thus, unlike solute contaminants, an acute exposure to a very small amount of contaminated water can cause immediate adverse health effects. Similarly, pathogens are larger than solutes. Thus, interactions with surfaces and settling become important even as processes important for solutes such as diffusion become less important. These differences are articulated in "Colloid Filtration Theory", a separate branch of pore-scale transport. Consequently, understanding pathogen processes requires changes in how groundwater systems are typically characterized, where the focus is on the leading edges of plumes and preferential flow paths, even if such features move only a very small fraction of the aquifer flow. Moreover, the relatively short survival times of pathogens in the subsurface require greater attention to very fast (solute transport mechanisms discussed here, a more encompassing view of water quality and source water protection is attained. With this more holistic view and theoretical understanding, better evaluations can be made regarding drinking water vulnerability and the relation between groundwater and human health.

  16. New trends in emerging pathogens.

    Science.gov (United States)

    Skovgaard, Niels

    2007-12-15

    The emergence of pathogens is the result of a number of impact in all parts of the food chain. The emerging technologies in food production explain how new pathogens can establish themselves in the food chain and compromise food safety. The impact of the food technology is analysed for several bacteria, such as Yersinia, Campylobacter, Arcobacter, Helicobacter pullorum, Enterobacter sakazakii, Mycobacterium avium spp. paratuberculosis, prions related to vCJD and others. The importance of the ability of many microbes to form VBNC forms is elaborated on. Research on culture independent methods may address this outstanding issue to the better understanding of emerging pathogens. The "demerging" of pathogens also occur, and examples of this are explained. The reaction of bacteria to stresses and sublethal treatments, and how exposure to one stress factor can confer resistance to other stresses, literally speaking causing contagious resistance, are explained. The implication of this e.g. in modern approaches of food preservation, such as Minimally processed Foods, is considerable. Intestinal colonization of EHEC may be regulated by Quorum sensing, and this ability of microbes plays an important role in the colonization of microbes in food and on food processing equipment, an important factor in the emergence of pathogens. The emergence of Saccharomyces cerevisiae, as an opportunistic human pathogen, used for centuries for food and production of alcoholic beverages, calls for research in molecular tools to distinguish between probiotic and clinical strains. Cyclospora cayetanensis and Norovirus outbreaks can no longer be designated as emerging pathogens, they share however one characteristic in the epidemiology of emerging nature, the importance of the hygiene in the primary production stage, including supply of potable water, and the application of GMP and the HACCP principles in the beginning of the food chain. Hepatitis E virus is a potential emerging food borne

  17. Applied Genomics of Foodborne Pathogens

    DEFF Research Database (Denmark)

    and customized source of information designed for and accessible to microbiologists interested in applying cutting-edge genomics in food safety and public health research. This book fills this void with a well-selected collection of topics, case studies, and bioinformatics tools contributed by experts......This book provides a timely and thorough snapshot into the emerging and fast evolving area of applied genomics of foodborne pathogens. Driven by the drastic advance of whole genome shot gun sequencing (WGS) technologies, genomics applications are becoming increasingly valuable and even essential...... at the forefront of foodborne pathogen genomics research....

  18. A global assembly of adult female mosquito mark-release-recapture data to inform the control of mosquito-borne pathogens

    NARCIS (Netherlands)

    Guerra, C.A.; Reiner Jr, R.C.; Perkins, T.A.; Lindsay, S.W.; Midega, J.T.; Brady, O.J.; Barker, C.M.; Reisen, W.K.; Harrington, L.C.; Takken, W.; Kitron, U.; Lloyd, A.L.; Hay, S.I.; Scott, T.W.; Smith, D.L.

    2014-01-01

    Background Pathogen transmission by mosquitos is known to be highly sensitive to mosquito bionomic parameters. Mosquito mark-release-recapture (MMRR) experiments are a standard method for estimating such parameters including dispersal, population size and density, survival, blood feeding frequency

  19. Effects of dairy manure storage conditions on the survival of E. coli O157:H7 and listeria

    Science.gov (United States)

    Dairy manure is regularly applied to crop fields as a solid or liquid to improve the soil nutrient status. However, pathogens may survive during manure storage and enter the environment during application. In this study, three storage practices were evaluated to understand the survival patterns of E...

  20. Applied survival analysis using R

    CERN Document Server

    Moore, Dirk F

    2016-01-01

    Applied Survival Analysis Using R covers the main principles of survival analysis, gives examples of how it is applied, and teaches how to put those principles to use to analyze data using R as a vehicle. Survival data, where the primary outcome is time to a specific event, arise in many areas of biomedical research, including clinical trials, epidemiological studies, and studies of animals. Many survival methods are extensions of techniques used in linear regression and categorical data, while other aspects of this field are unique to survival data. This text employs numerous actual examples to illustrate survival curve estimation, comparison of survivals of different groups, proper accounting for censoring and truncation, model variable selection, and residual analysis. Because explaining survival analysis requires more advanced mathematics than many other statistical topics, this book is organized with basic concepts and most frequently used procedures covered in earlier chapters, with more advanced topics...

  1. Lack of direct effects of agrochemicals on zoonotic pathogens and fecal indicator bacteria.

    Science.gov (United States)

    Staley, Zachery R; Senkbeil, Jacob K; Rohr, Jason R; Harwood, Valerie J

    2012-11-01

    Agrochemicals, fecal indicator bacteria (FIB), and pathogens frequently contaminate water simultaneously. No significant direct effects of fertilizer, atrazine, malathion, and chlorothalonil on the survival of Escherichia coli, Enterococcus faecalis, Salmonella enterica, human polyomaviruses, and adenovirus were detected, supporting the assertion that previously observed effects of agrochemicals on FIB were indirect.

  2. Isolation, identification, characterization and antibiotic sensitivity profile of pathogenic Legionella pneumophila isolates from different water sources

    Directory of Open Access Journals (Sweden)

    Kannan Subbaram

    2017-05-01

    Conclusions: Serious and fatal L. pneumophila infections may be transmitted through water. Legionella can survive under various conditions in various water sources. L. pneumophila is the important pathogen causing human disease. Great challenge prevails to health care professionals because these Legionellae acquired antibiotic resistance to many routinely prescribed antibiotics.

  3. Functional Redundancy and Ecological Innovation Shape the Circulation of Tick-Transmitted Pathogens

    Directory of Open Access Journals (Sweden)

    Agustín Estrada-Peña

    2017-05-01

    Full Text Available Ticks are vectors of pathogens affecting human and animal health worldwide. Nevertheless, the ecological and evolutionary interactions between ticks, hosts, and pathogens are largely unknown. Here, we integrated a framework to evaluate the associations of the tick Ixodes ricinus with its hosts and environmental niches that impact pathogen circulation. The analysis of tick-hosts association suggested that mammals and lizards were the ancestral hosts of this tick species, and that a leap to Aves occurred around 120 M years ago. The signature of the environmental variables over the host's phylogeny revealed the existence of two clades of vertebrates diverging along a temperature and vegetation split. This is a robust proof that the tick probably experienced a colonization of new niches by adapting to a large set of new hosts, Aves. Interestingly, the colonization of Aves as hosts did not increase significantly the ecological niche of I. ricinus, but remarkably Aves are super-spreaders of pathogens. The disparate contribution of Aves to the tick-host-pathogen networks revealed that I. ricinus evolved to maximize habitat overlap with some hosts that are super-spreaders of pathogens. These results supported the hypothesis that large host networks are not a requirement of tick survival but pathogen circulation. The biological cost of tick adaptation to non-optimal environmental conditions might be balanced by molecular mechanisms triggered by the pathogens that we have only begun to understand.

  4. Mixed infections reveal virulence differences between host-specific bee pathogens.

    Science.gov (United States)

    Klinger, Ellen G; Vojvodic, Svjetlana; DeGrandi-Hoffman, Gloria; Welker, Dennis L; James, Rosalind R

    2015-07-01

    Dynamics of host-pathogen interactions are complex, often influencing the ecology, evolution and behavior of both the host and pathogen. In the natural world, infections with multiple pathogens are common, yet due to their complexity, interactions can be difficult to predict and study. Mathematical models help facilitate our understanding of these evolutionary processes, but empirical data are needed to test model assumptions and predictions. We used two common theoretical models regarding mixed infections (superinfection and co-infection) to determine which model assumptions best described a group of fungal pathogens closely associated with bees. We tested three fungal species, Ascosphaera apis, Ascosphaera aggregata and Ascosphaera larvis, in two bee hosts (Apis mellifera and Megachile rotundata). Bee survival was not significantly different in mixed infections vs. solo infections with the most virulent pathogen for either host, but fungal growth within the host was significantly altered by mixed infections. In the host A. mellifera, only the most virulent pathogen was present in the host post-infection (indicating superinfective properties). In M. rotundata, the most virulent pathogen co-existed with the lesser-virulent one (indicating co-infective properties). We demonstrated that the competitive outcomes of mixed infections were host-specific, indicating strong host specificity among these fungal bee pathogens. Published by Elsevier Inc.

  5. Nuclear War Survival Skills

    Energy Technology Data Exchange (ETDEWEB)

    Kearny, C.H.

    2002-06-24

    The purpose of this book is to provide Americans with information and instructions that will significantly increase their chances of surviving a possible nuclear attack. It brings together field-tested instructions that, if followed by a large fraction of Americans during a crisis that preceded an attack, could save millions of lives. The author is convinced that the vulnerability of our country to nuclear threat or attack must be reduced and that the wide dissemination of the information contained in this book would help achieve that objective of our overall defense strategy.

  6. Survival after blood transfusion

    DEFF Research Database (Denmark)

    Kamper-Jørgensen, Mads; Ahlgren, Martin; Rostgaard, Klaus

    2008-01-01

    of transfusion recipients in Denmark and Sweden followed for up to 20 years after their first blood transfusion. Main outcome measure was all-cause mortality. RESULTS: A total of 1,118,261 transfusion recipients were identified, of whom 62.0 percent were aged 65 years or older at the time of their first...... the SMR remained significantly 1.3-fold increased. CONCLUSION: The survival and relative mortality patterns among blood transfusion recipients were characterized with unprecedented detail and precision. Our results are relevant to assessments of the consequences of possible transfusion-transmitted disease...... as well as for cost-benefit estimation of new blood safety interventions....

  7. Pathogen disgust and interpersonal personality

    NARCIS (Netherlands)

    Kupfer, Tom R.; Tybur, Joshua M.

    2017-01-01

    The behavioral immune system includes motivational systems for avoiding contact with pathogens, including those transmitted by other people. Motivations to avoid others may depend not only on the perceived risk of infection but also on perceived benefits of social interaction. Based on this idea, we

  8. Lectins in human pathogenic fungi.

    Science.gov (United States)

    Gallegos, Belém; Martínez, Ruth; Pérez, Laura; Del Socorro Pina, María; Perez, Eduardo; Hernández, Pedro

    2014-01-01

    Lectins are carbohydrate-binding proteins widely distributed in nature. They constitute a highly diverse group of proteins consisting of many different protein families that are, in general, structurally unrelated. In the last few years, mushroom and other fungal lectins have attracted wide attention due to their antitumour, antiproliferative and immunomodulatory activities. The present mini-review provides concise information about recent developments in understanding lectins from human pathogenic fungi. A bibliographic search was performed in the Science Direct and PubMed databases, using the following keywords "lectin", "fungi", "human" and "pathogenic". Lectins present in fungi have been classified; however, the role played by lectins derived from human pathogenic fungi in infectious processes remains uncertain; thus, this is a scientific field requiring more research. This manuscript is part of the series of works presented at the "V International Workshop: Molecular genetic approaches to the study of human pathogenic fungi" (Oaxaca, Mexico, 2012). Copyright © 2013 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

  9. Pathogenicity of Shigella in chickens.

    Science.gov (United States)

    Shi, Run; Yang, Xia; Chen, Lu; Chang, Hong-tao; Liu, Hong-ying; Zhao, Jun; Wang, Xin-wei; Wang, Chuan-qing

    2014-01-01

    Shigellosis in chickens was first reported in 2004. This study aimed to determine the pathogenicity of Shigella in chickens and the possibility of cross-infection between humans and chickens. The pathogenicity of Shigella in chickens was examined via infection of three-day-old SPF chickens with Shigella strain ZD02 isolated from a human patient. The virulence and invasiveness were examined by infection of the chicken intestines and primary chicken intestinal epithelial cells. The results showed Shigella can cause death via intraperitoneal injection in SPF chickens, but only induce depression via crop injection. Immunohistochemistry and transmission electron microscopy revealed the Shigella can invade the intestinal epithelia. Immunohistochemistry of the primary chicken intestinal epithelial cells infected with Shigella showed the bacteria were internalized into the epithelial cells. Electron microscopy also confirmed that Shigella invaded primary chicken intestinal epithelia and was encapsulated by phagosome-like membranes. Our data demonstrate that Shigella can invade primary chicken intestinal epithelial cells in vitro and chicken intestinal mucosa in vivo, resulting in pathogenicity and even death. The findings suggest Shigella isolated from human or chicken share similar pathogenicity as well as the possibility of human-poultry cross-infection, which is of public health significance.

  10. Survival curves for irradiated cells

    International Nuclear Information System (INIS)

    Gibson, D.K.

    1975-01-01

    The subject of the lecture is the probability of survival of biological cells which have been subjected to ionising radiation. The basic mathematical theories of cell survival as a function of radiation dose are developed. A brief comparison with observed survival curves is made. (author)

  11. Survival with a helping hand: Campylobacter and microbiota

    Directory of Open Access Journals (Sweden)

    Ivana eIndikova

    2015-11-01

    Full Text Available Campylobacteriosis is the most important bacterial food-borne disease in the developed world. Consumption of chicken meat, beef or raw milk, direct contact with ruminants and exposure to contaminated surface water or even consumption of tap water have been identified as risk factors for human disease. However, the most important risk factor is consumption of and/or handling contaminated chicken. Campylobacter spp. are fastidious microorganisms but must somehow survive outside the host, especially in food and agricultural environments and also resist the innate and humoral immune responses inside the host. In this paper we hypothesize that other microorganisms in mixed populations with Campylobacter may act to improve survival outside the host and may also protect the pathogen against the intestinal immune system. Our evidence for this hypothesis is based on: 1. newly generated microbial community analysis; 2. the prolonged survival of Campylobacter in mixed species biofilms and in co-culture with environmental bacteria; 3. improved survival in amoebae and rumen fluid; 4. sulphur release and iron uptake systems within the intestinal lumen. This would make Campylobacter an exceptional food-borne pathogen. With this in mind, new strategies are necessary to combat Campylobacter along the total food chain.

  12. Selection of pathogen-resistant mutants in rapeseed

    International Nuclear Information System (INIS)

    Spanier, A.; Roebbelen, G.

    1990-01-01

    Full text: Significant yield reductions are due to Phoma lingam and Alternaria brassicae. Toxin containing culture filtrates of the pathogens as well as concentrated toxins of Phoma (Sirodesmins) are used for resistance selections in in-vitro cultures of haploid rapeseed materials. A few days after transfer of the in-vitro materials to the selective media the inhibitory effect of both the culture filtrates as well as the Sirodesmins was apparent. Clones were obtained, surviving several transfers onto toxin containing media. Further experiments shall clarify whether the toxin tolerance, selected in vitro at the cell level, is expressed in the differentiated plant in the greenhouse and finally in the field. (author)

  13. Survival of Listeria monocytogenes on a conveyor belt material with or without antimicrobial additives

    OpenAIRE

    Chaitiemwong, N.; Hazeleger, W.C.; Beumer, R.R.

    2010-01-01

    Survival of Listeria monocytogenes on a conveyor belt material with or without antimicrobial additives, in the absence or presence of food debris from meat, fish and vegetables and at temperatures of 10, 25 and 37 °C was investigated. The pathogen survived best at 10 °C, and better at 25 °C than at 37 °C on both conveyor belt materials. The reduction in the numbers of the pathogen on belt material with antimicrobial additives in the first 6 h at 10 °C was 0.6 log unit, which was significantly...

  14. Nuclear war survival skills

    International Nuclear Information System (INIS)

    Kearney, C.H.

    1979-09-01

    This book includes chapters on psychological preparations, warning and communications, and evacuation. It describes the building of expedient shelters, their ventilation and cooling, the purification and storage of adequate water, the processing and cooking of whole grains and legumes, fallout meters, protection against fires and carbon monoxide, and expedient furnishings for shelters. Other chapters cover sanitation and preventive medicine, medical advice for nuclear survivors lacking the help of doctors, improvised footwear and clothing, and advice on minimum preparations that can be made at low cost and should be made before a crisis arises. One appendix of the handbook gives detailed, field-tested instructions for building six types of earth-covered expedient fallout shelters, with criteria to guide the choice of which shelter to build. Others contain instructions for making an efficient shelter-ventilating pump and a homemade fallout meter that is accurate and dependable with inexpensive materials found in most households. This report is primarily a compilation and summary of civil defense measures and inventions developed at ORNL over the past 14 years and field-tested in six states, from Florida to Utah. It is the first comprehensive handbook of survival information for use by untrained citizens who want to improve their chances of surviving a possible nuclear attack. Sections may be easily excerpted and reproduced for mass distribution through news media

  15. Survival and transport of faecal bacteria in agricultural soils

    DEFF Research Database (Denmark)

    Bech, Tina Bundgaard

    Today, there is yearly applied 34 million tonnes of animal waste to arable land in Denmark. This waste may contain pathogenic zoonotic bacteria and/or antibiotic resistant bacteria, and when applied to arable land there is a risk of contaminating groundwater, surface water, feeding animals or fresh...... produce. Prediction of faecal bacterial survival and transport in the soil environment will help minimize the risk of contamination, as best management practices can be adapted to this knowledge. The aim of this Ph.D. is to study factors influencing faecal bacteria survival and transport in soil...... – it is based on both field scale and lab scale experiments. The influence of application method and slurry properties has been tested on both survival and transport....

  16. Biofilm formation enhances Helicobacter pylori survivability in vegetables.

    Science.gov (United States)

    Ng, Chow Goon; Loke, Mun Fai; Goh, Khean Lee; Vadivelu, Jamuna; Ho, Bow

    2017-04-01

    To date, the exact route and mode of transmission of Helicobacter pylori remains elusive. The detection of H. pylori in food using molecular approaches has led us to postulate that the gastric pathogen may survive in the extragastric environment for an extended period. In this study, we show that H. pylori prolongs its survival by forming biofilm and micro-colonies on vegetables. The biofilm forming capability of H. pylori is both strain and vegetable dependent. H. pylori strains were classified into high and low biofilm formers based on their highest relative biofilm units (BU). High biofilm formers survived longer on vegetables compared to low biofilm formers. The bacteria survived better on cabbage compared to other vegetables tested. In addition, images captured on scanning electron and confocal laser scanning microscopes revealed that the bacteria were able to form biofilm and reside as micro-colonies on vegetable surfaces, strengthening the notion of possible survival of H. pylori on vegetables for an extended period of time. Taken together, the ability of H. pylori to form biofilm on vegetables (a common food source for human) potentially plays an important role in its survival, serving as a mode of transmission of H. pylori in the extragastric environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Cra negatively regulates acid survival in Yersinia pseudotuberculosis.

    Science.gov (United States)

    Hu, Yangbo; Lu, Pei; Zhang, Yong; Li, Yunlong; Li, Lamei; Huang, Li; Chen, Shiyun

    2011-04-01

    Survival in acidic environments is important for successful infection of gastrointestinal pathogens. Many bacteria have evolved elaborate mechanisms by inducing or repressing gene expression, which subsequently provide pH homeostasis and enable acid survival. In this study, we employed comparative proteomic analysis to identify the acid-responsive proteins of a food-borne enteric bacterium, Yersinia pseudotuberculosis. The expression level of eight proteins involved in carbohydrate metabolism was up- or downregulated over twofold at pH 4.5 compared with pH 7.0. The role of a global transcriptional regulator catabolite repressor/activator Cra was further studied in this acid survival process. lacZ-fusion analysis showed that expression of cra was repressed under acidic pH. Deletion of the cra gene increased acid survival by 10-fold, whereas complementation restored the wild-type phenotype. These results lead us to propose that, in response to acidic pH, the expression of cra gene is downregulated to increase acid survival. This is the first study to demonstrate the regulatory role of Cra in acid survival in an enteric bacterium. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  18. A Plant Bacterial Pathogen Manipulates Its Insect Vector's Energy Metabolism

    Science.gov (United States)

    Hijaz, Faraj; Ebert, Timothy A.; Rogers, Michael E.

    2016-01-01

    ABSTRACT Insect-transmitted plant-pathogenic bacteria may alter their vectors' fitness, survival, behavior, and metabolism. Because these pathogens interact with their vectors on the cellular and organismal levels, potential changes at the biochemical level might occur. “Candidatus Liberibacter asiaticus” (CLas) is transmitted in a persistent, circulative, and propagative manner. The genome of CLas revealed the presence of an ATP translocase that mediates the uptake of ATP and other nucleotides from medium to achieve its biological processes, such as growth and multiplication. Here, we showed that the levels of ATP and many other nucleotides were significantly higher in CLas-infected than healthy psyllids. Gene expression analysis showed upregulation for ATP synthase subunits, while ATPase enzyme activity showed a decrease in ATPase activity. These results indicated that CLas stimulated Diaphorina citri to produce more ATP and many other energetic nucleotides, while it may inhibit their consumption by the insect. As a result of ATP accumulation, the adenylated energy charge (AEC) increased and the AMP/ATP and ADP/ATP ratios decreased in CLas-infected D. citri psyllids. Survival analysis confirmed a shorter life span for CLas-infected D. citri psyllids. In addition, electropenetrography showed a significant reduction in total nonprobing time, salivation time, and time from the last E2 (phloem ingestion) to the end of recording, indicating that CLas-infected psyllids were at a higher hunger level and they tended to forage more often. This increased feeding activity reflects the CLas-induced energetic stress. In conclusion, CLas alters the energy metabolism of its psyllid vector, D. citri, in order to secure its need for energetic nucleotides. IMPORTANCE Insect transmission of plant-pathogenic bacteria involves propagation and circulation of the bacteria within their vectors. The transmission process is complex and requires specific interactions at the molecular

  19. Surface adhesins and exopolymers of selected foodborne pathogens

    DEFF Research Database (Denmark)

    Jaglic, Zoran; Desvaux, Mickaël; Weiss, Agnes

    2014-01-01

    The ability of bacteria to bind different compounds and to adhere to biotic and abiotic surfaces provides them with a range of advantages, such as colonization of various tissues, internalisation, avoidance of an immune response and survival and persistence in the environment. A variety of bacter......The ability of bacteria to bind different compounds and to adhere to biotic and abiotic surfaces provides them with a range of advantages, such as colonization of various tissues, internalisation, avoidance of an immune response and survival and persistence in the environment. A variety...... of bacterial surface structures are involved in this process and these promote bacterial adhesion in a more or less specific manner. In this review, we will focus on those surface adhesins and exopolymers in selected foodborne pathogens that are involved mainly in primary adhesion. Their role in biofilm...

  20. Wildlife translocation: the conservation implications of pathogen exposure and genetic heterozygosity

    Science.gov (United States)

    2011-01-01

    Background A key challenge for conservation biologists is to determine the most appropriate demographic and genetic management strategies for wildlife populations threatened by disease. We explored this topic by examining whether genetic background and previous pathogen exposure influenced survival of translocated animals when captive-bred and free-ranging bighorn sheep (Ovis canadensis) were used to re-establish a population that had been extirpated in the San Andres Mountains in New Mexico, USA. Results Although the free-ranging source population had significantly higher multi-locus heterozygosity at 30 microsatellite loci than the captive bred animals, neither source population nor genetic background significantly influenced survival or cause of death. The presence of antibodies to a respiratory virus known to cause pneumonia was associated with increased survival, but there was no correlation between genetic heterozygosity and the presence of antibodies to this virus. Conclusions Although genetic theory predicts otherwise, increased heterozygosity was not associated with increased fitness (survival) among translocated animals. While heterosis or genetic rescue effects may occur in F1 and later generations as the two source populations interbreed, we conclude that previous pathogen exposure was a more important marker than genetic heterozygosity for predicting survival of translocated animals. Every wildlife translocation is an experiment, and whenever possible, translocations should be designed and evaluated to test hypotheses that will further improve our understanding of how pathogen exposure and genetic variability influence fitness. PMID:21284886

  1. Wildlife translocation: the conservation implications of pathogen exposure and genetic heterozygosity

    Directory of Open Access Journals (Sweden)

    Penedo M Cecilia T

    2011-02-01

    Full Text Available Abstract Background A key challenge for conservation biologists is to determine the most appropriate demographic and genetic management strategies for wildlife populations threatened by disease. We explored this topic by examining whether genetic background and previous pathogen exposure influenced survival of translocated animals when captive-bred and free-ranging bighorn sheep (Ovis canadensis were used to re-establish a population that had been extirpated in the San Andres Mountains in New Mexico, USA. Results Although the free-ranging source population had significantly higher multi-locus heterozygosity at 30 microsatellite loci than the captive bred animals, neither source population nor genetic background significantly influenced survival or cause of death. The presence of antibodies to a respiratory virus known to cause pneumonia was associated with increased survival, but there was no correlation between genetic heterozygosity and the presence of antibodies to this virus. Conclusions Although genetic theory predicts otherwise, increased heterozygosity was not associated with increased fitness (survival among translocated animals. While heterosis or genetic rescue effects may occur in F1 and later generations as the two source populations interbreed, we conclude that previous pathogen exposure was a more important marker than genetic heterozygosity for predicting survival of translocated animals. Every wildlife translocation is an experiment, and whenever possible, translocations should be designed and evaluated to test hypotheses that will further improve our understanding of how pathogen exposure and genetic variability influence fitness.

  2. Pathogen reduction of blood components.

    Science.gov (United States)

    Solheim, Bjarte G

    2008-08-01

    Thanks to many blood safety interventions introduced in developed countries the risk of transfusion transmitted infections has become exceedingly small in these countries. However, emerging pathogens still represent a serious challenge, as demonstrated by West Nile virus in the US and more recently by Chikungunya virus in the Indian Ocean. In addition bacterial contamination, particularly in platelets, and protozoa transmitted by blood components still represent sizeable risks in developed countries. In developing countries the risk of all transfusion transmitted infections is still high due to insufficient funding and organisation of the health service. Pathogen reduction of pooled plasma products has virtually eliminated the risk of transfusion transmitted infections, without compromising the quality of the products significantly. Pathogen reduction of blood components has been much more challenging. Solvent detergent treatment which has been so successfully applied for plasma products dissolves cell membranes, and can, therefore, only be applied for plasma and not for cellular blood components. Targeting of nucleic acids has been another method for pathogen inactivation of plasma and the only approach possible for cellular blood products. As documented in more than 15 year's track record, solvent detergent treatment of pooled plasma can yield high quality plasma. The increased risk for contamination by unknown viruses due to pooling is out weighed by elimination of TRALI, significant reduction in allergic reactions and standardisation of the product. Recently, a promising method for solvent detergent treatment of single donor plasma units has been published. Methylene blue light treatment of single donor plasma units has a similar long track record as pooled solvent detergent treated plasma; but the method is less well documented and affects coagulation factor activity more. Psoralen light treated plasma has only recently been introduced (CE marked in Europe

  3. Surviving Sepsis Campaign

    DEFF Research Database (Denmark)

    Rhodes, Andrew; Evans, Laura E; Alhazzani, Waleed

    2017-01-01

    OBJECTIVE: To provide an update to "Surviving Sepsis Campaign Guidelines for Management of Sepsis and Septic Shock: 2012." DESIGN: A consensus committee of 55 international experts representing 25 international organizations was convened. Nominal groups were assembled at key international meetings...... (for those committee members attending the conference). A formal conflict-of-interest (COI) policy was developed at the onset of the process and enforced throughout. A stand-alone meeting was held for all panel members in December 2015. Teleconferences and electronic-based discussion among subgroups......, and evidence profiles were generated. Each subgroup generated a list of questions, searched for best available evidence, and then followed the principles of the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system to assess the quality of evidence from high to very low...

  4. Surviving Sepsis Campaign

    DEFF Research Database (Denmark)

    Rhodes, Andrew; Evans, Laura E; Alhazzani, Waleed

    2017-01-01

    OBJECTIVE: To provide an update to "Surviving Sepsis Campaign Guidelines for Management of Sepsis and Septic Shock: 2012". DESIGN: A consensus committee of 55 international experts representing 25 international organizations was convened. Nominal groups were assembled at key international meetings...... (for those committee members attending the conference). A formal conflict-of-interest (COI) policy was developed at the onset of the process and enforced throughout. A stand-alone meeting was held for all panel members in December 2015. Teleconferences and electronic-based discussion among subgroups......, and evidence profiles were generated. Each subgroup generated a list of questions, searched for best available evidence, and then followed the principles of the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system to assess the quality of evidence from high to very low...

  5. Surviving relatives after suicide

    DEFF Research Database (Denmark)

    Nørrelykke, Helle; Cohrt, Pernille

    and that suicide has become a subject of research, prevention and treatment. Auxiliary Strategies In the 1990s there have been established the Centre for Suicide Research and the Centre for Prevention of Suicide in Denmark and there has been drafted a national policy document which focuses on the need......We would like to focus on the surviving relatives after suicides, because it is generally accepted that it is especially difficult to recover after the loss from suicide and because we know as a fact that one suicide affects five persons on average. Every year approximately 700 people commit...... suicide in Denmark. This means that at least 400 people undergo the trauma it is when one of their near relatives commits suicide. We also know that the loss from suicide involves a lot of conflicting feelings - like anger, shame, guilt and loss and that the lack of therapy/treatment of these difficult...

  6. Neuroepigenetic Regulation of Pathogenic Memories.

    Science.gov (United States)

    Sillivan, Stephanie E; Vaissière, Thomas; Miller, Courtney A

    2015-01-01

    Our unique collection of memories determines our individuality and shapes our future interactions with the world. Remarkable advances into the neurobiological basis of memory have identified key epigenetic mechanisms that support the stability of memory. Various forms of epigenetic regulation at the levels of DNA methylation, histone modification, and non-coding RNAs (ncRNAs) can modulate transcriptional and translational events required for memory processes. By changing the cellular profile in the brain's emotional, reward, and memory circuits, these epigenetic modifications have also been linked to perseverant, pathogenic memories. In this review, we will delve into the relevance of epigenetic dysregulation to pathogenic memory mechanisms by focusing on two neuropsychiatric disorders perpetuated by aberrant memory associations: substance use disorder (SUD) and post-traumatic stress disorder (PTSD). As our understanding improves, neuroepigenetic mechanisms may someday be harnessed to develop novel therapeutic targets for the treatment of these chronic, relapsing disorders.

  7. Neuroepigenetic regulation of pathogenic memories

    Directory of Open Access Journals (Sweden)

    Stephanie E. Sillivan

    2015-01-01

    Full Text Available Our unique collection of memories determines our individuality and shapes our future interactions with the world. Remarkable advances into the neurobiological basis of memory have identified key epigenetic mechanisms that support the stability of memory. Various forms of epigenetic regulation at the levels of DNA methylation, histone modification, and noncoding RNAs can modulate transcriptional and translational events required for memory processes. By changing the cellular profile in the brain’s emotional, reward, and memory circuits, these epigenetic modifications have also been linked to perseverant, pathogenic memories. In this review, we will delve into the relevance of epigenetic dysregulation to pathogenic memory mechanisms by focusing on 2 neuropsychiatric disorders perpetuated by aberrant memory associations: substance use disorder and post-traumatic stress disorder. As our understanding improves, neuroepigenetic mechanisms may someday be harnessed to develop novel therapeutic targets for the treatment of these chronic, relapsing disorders.

  8. Antimicrobial resistance of mastitis pathogens.

    Science.gov (United States)

    Oliver, Stephen P; Murinda, Shelton E

    2012-07-01

    Antibiotics are used extensively in the dairy industry to combat disease and to improve animal performance. Antibiotics such as penicillin, cephalosporin, streptomycin, and tetracycline are used for the treatment and prevention of diseases affecting dairy cows caused by a variety of gram-positive and gram-negative bacteria. Antibiotics are often administrated routinely to entire herds to prevent mastitis during the dry period. An increase in the incidence of disease in a herd generally results in increased use of antimicrobials, which in turn increases the potential for antibiotic residues in milk and the potential for increased bacterial resistance to antimicrobials. Continued use of antibiotics in the treatment and prevention of diseases of dairy cows will continue to be scrutinized. It is clear that strategies employing the prudent use of antimicrobials are needed. This clearly illustrates the importance of effective herd disease prevention and control programs. Based on studies published to date, scientific evidence does not support widespread, emerging resistance among mastitis pathogens to antibacterial drugs even though many of these antibiotics have been used in the dairy industry for treatment and prevention of disease for several decades. However, it is clear that use of antibiotics in dairy cows can contribute to increased antimicrobial resistance. While antimicrobial resistance does occur, we are of the opinion that the advantages of using antibiotics for the treatment of mastitis far outweigh the disadvantages. The clinical consequences of antimicrobial resistance of dairy pathogens affecting humans appear small. Antimicrobial resistance among dairy pathogens, particularly those found in milk, is likely not a human health concern as long as the milk is pasteurized. However, there are an increasing number of people who choose to consume raw milk. Transmission of an antimicrobial-resistant mastitis pathogen and/or foodborne pathogen to humans could occur

  9. Methods for air cleaning and protection of building occupants from airborne pathogens

    DEFF Research Database (Denmark)

    Bolashikov, Zhecho Dimitrov; Melikov, Arsen Krikor

    2009-01-01

    germicidal irradiation (UVGI), photocatalytic oxidation (PCO), plasmacluster ions and other technologies for air disinfection and purification from pathogens are analyzed with respect to currently used air distribution principles. The importance of indoor air characteristics, such as temperature, relative...... of transmission, i.e. the generation of pathogen laden droplets originating in the respiratory tract of an infected individual, the survivability of the pathogens, their dispersal indoors and their transfer to a healthy person are reviewed. The advantages and the drawbacks of air dilution, filtration, ultraviolet...... humidity and velocity for the efficiency of each method is analyzed, taking into consideration the nature of the pathogens themselves. The applicability of the methods to the different types of total volume air distribution used at present indoors, i.e. mixing, displacement and underfloor ventilation...

  10. The BER necessities: the repair of DNA damage in human-adapted bacterial pathogens.

    Science.gov (United States)

    van der Veen, Stijn; Tang, Christoph M

    2015-02-01

    During colonization and disease, bacterial pathogens must survive the onslaught of the host immune system. A key component of the innate immune response is the generation of reactive oxygen and nitrogen species by phagocytic cells, which target and disrupt pathogen molecules, particularly DNA, and the base excision repair (BER) pathway is the most important mechanism for the repair of such oxidative DNA damage. In this Review, we discuss how the human-specific pathogens Mycobacterium tuberculosis, Helicobacter pylori and Neisseria meningitidis have evolved specialized mechanisms of DNA repair, particularly their BER pathways, compared with model organisms such as Escherichia coli. This specialization in DNA repair is likely to reflect the distinct niches occupied by these important human pathogens in the host.

  11. Evolutionary biology of bacterial and fungal pathogens

    National Research Council Canada - National Science Library

    Baquero, F

    2008-01-01

    ... and Evolutionary Dynamics of Pathogens * 21 Keith A. Crandall and Marcos Pérez-Losada II. Evolutionary Genetics of Microbial Pathogens 4. Environmental and Social Influences on Infectious Disea...

  12. Plant Pathogenicity in Spaceflight Environments

    OpenAIRE

    Bishop, Deborah L.; Levine, Howard G.; Anderson, Anne J.

    1996-01-01

    Plants grown in microgravity are subject to many environmental stresses, which may promote microbial growth and result in pathogenicity to the plant. Recent plant experiments with super dwarf wheat aboard the NASA Space Shuttle and NASA/Russian Mir Space Station returned from the mission with severe degrees of fungal contamination. Understanding the cause of such microbial contamination and methods to eliminate it are necessary prerequisites for continued plant growth and development studies ...

  13. Proteomics of Plant Pathogenic Fungi

    Directory of Open Access Journals (Sweden)

    Raquel González-Fernández

    2010-01-01

    Full Text Available Plant pathogenic fungi cause important yield losses in crops. In order to develop efficient and environmental friendly crop protection strategies, molecular studies of the fungal biological cycle, virulence factors, and interaction with its host are necessary. For that reason, several approaches have been performed using both classical genetic, cell biology, and biochemistry and the modern, holistic, and high-throughput, omic techniques. This work briefly overviews the tools available for studying Plant Pathogenic Fungi and is amply focused on MS-based Proteomics analysis, based on original papers published up to December 2009. At a methodological level, different steps in a proteomic workflow experiment are discussed. Separate sections are devoted to fungal descriptive (intracellular, subcellular, extracellular and differential expression proteomics and interactomics. From the work published we can conclude that Proteomics, in combination with other techniques, constitutes a powerful tool for providing important information about pathogenicity and virulence factors, thus opening up new possibilities for crop disease diagnosis and crop protection.

  14. Minisequencing mitochondrial DNA pathogenic mutations

    Directory of Open Access Journals (Sweden)

    Carracedo Ángel

    2008-04-01

    Full Text Available Abstract Background There are a number of well-known mutations responsible of common mitochondrial DNA (mtDNA diseases. In order to overcome technical problems related to the analysis of complete mtDNA genomes, a variety of different techniques have been proposed that allow the screening of coding region pathogenic mutations. Methods We here propose a minisequencing assay for the analysis of mtDNA mutations. In a single reaction, we interrogate a total of 25 pathogenic mutations distributed all around the whole mtDNA genome in a sample of patients suspected for mtDNA disease. Results We have detected 11 causal homoplasmic mutations in patients suspected for Leber disease, which were further confirmed by standard automatic sequencing. Mutations m.11778G>A and m.14484T>C occur at higher frequency than expected by change in the Galician (northwest Spain patients carrying haplogroup J lineages (Fisher's Exact test, P-value Conclusion We here developed a minisequencing genotyping method for the screening of the most common pathogenic mtDNA mutations which is simple, fast, and low-cost. The technique is robust and reproducible and can easily be implemented in standard clinical laboratories.

  15. Molecular Mechanisms of Bacterial Pathogenicity

    Science.gov (United States)

    Fuchs, Thilo Martin

    Cautious optimism has arisen over recent decades with respect to the long struggle against bacteria, viruses, and parasites. This has been offset, however, by a fatal complacency stemming from previous successes such as the development of antimicrobial drugs, the eradication of smallpox, and global immunization programs. Infectious diseases nevertheless remain the world's leading cause of death, killing at least 17 million persons annually [61]. Diarrheal diseases caused by Vibrio cholerae or Shigella dysenteriae kill about 3 million persons every year, most of them young children: Another 4 million die of tuberculosis or tetanus. Outbreaks of diphtheria in Eastern Europe threatens the population with a disease that had previously seemed to be overcome. Efforts to control infectious diseases more comprehensively are undermined not only by socioeconomic conditions but also by the nature of the pathogenic organisms itself; some isolates of Staphylococcus aureus and Enterobacter have become so resistant to drugs by horizontal gene transfer that they are almost untreatable. In addition, the mechanism of genetic variability helps pathogens to evade the human immune system, thus compromising the development of powerful vaccines. Therefore detailed knowledge of the molecular mechanisms of microbial pathogenicity is absolutely necessary to develop new strategies against infectious diseases and thus to lower their impact on human health and social development.

  16. Effectiveness of irradiation in killing pathogens

    International Nuclear Information System (INIS)

    Yeager, J.G.; Ward, R.L.

    1980-01-01

    United States Environmental Protection Agency regulations include gamma ray irradiation of sludge as an approved Process to Further Reduce Pathogens (PFRP) prior to land application. Research at Sandia National Laboratories on pathogen inactivation in sludge by gamma irradiation has demonstrated that the 1 Mrad PFRP dose is capable, by itself, of eliminating bacterial, fungal, and parasitic pathogens from sludge. Gamma irradiation of sludge in conjunction with the required Processes to Significantly Reduce Pathogens (PSRP) should also eliminate the viral hazard from wastewater sludges

  17. 76 FR 24793 - Highly Pathogenic Avian Influenza

    Science.gov (United States)

    2011-05-03

    .... APHIS-2006-0074] RIN 0579-AC36 Highly Pathogenic Avian Influenza AGENCY: Animal and Plant Health... any subtype of highly pathogenic avian influenza is considered to exist. The interim rule also imposed... avian influenza, or that have moved through regions where any subtype of highly pathogenic avian...

  18. Global distribution of two fungal pathogens threatening endangered sea turtles.

    Science.gov (United States)

    Sarmiento-Ramírez, Jullie M; Abella-Pérez, Elena; Phillott, Andrea D; Sim, Jolene; van West, Pieter; Martín, María P; Marco, Adolfo; Diéguez-Uribeondo, Javier

    2014-01-01

    Nascent fungal infections are currently considered as one of the main threats for biodiversity and ecosystem health, and have driven several animal species into critical risk of extinction. Sea turtles are one of the most endangered groups of animals and only seven species have survived to date. Here, we described two pathogenic species, i.e., Fusarium falciforme and Fusarium keratoplasticum, that are globally distributed in major turtle nesting areas for six sea turtle species and that are implicated in low hatch success. These two fungi possess key biological features that are similar to emerging pathogens leading to host extinction, e.g., high virulence, and a broad host range style of life. Their optimal growth temperature overlap with the optimal incubation temperature for eggs, and they are able to kill up to 90% of the embryos. Environmental forcing, e.g., tidal inundation and clay/silt content of nests, were correlated to disease development. Thus, these Fusarium species constitute a major threat to sea turtle nests, especially to those experiencing environmental stressors. These findings have serious implications for the survival of endangered sea turtle populations and the success of conservation programs worldwide.

  19. Global distribution of two fungal pathogens threatening endangered sea turtles.

    Directory of Open Access Journals (Sweden)

    Jullie M Sarmiento-Ramírez

    Full Text Available Nascent fungal infections are currently considered as one of the main threats for biodiversity and ecosystem health, and have driven several animal species into critical risk of extinction. Sea turtles are one of the most endangered groups of animals and only seven species have survived to date. Here, we described two pathogenic species, i.e., Fusarium falciforme and Fusarium keratoplasticum, that are globally distributed in major turtle nesting areas for six sea turtle species and that are implicated in low hatch success. These two fungi possess key biological features that are similar to emerging pathogens leading to host extinction, e.g., high virulence, and a broad host range style of life. Their optimal growth temperature overlap with the optimal incubation temperature for eggs, and they are able to kill up to 90% of the embryos. Environmental forcing, e.g., tidal inundation and clay/silt content of nests, were correlated to disease development. Thus, these Fusarium species constitute a major threat to sea turtle nests, especially to those experiencing environmental stressors. These findings have serious implications for the survival of endangered sea turtle populations and the success of conservation programs worldwide.

  20. Network survivability performance (computer diskette)

    Science.gov (United States)

    1993-11-01

    File characteristics: Data file; 1 file. Physical description: 1 computer diskette; 3 1/2 in.; high density; 2.0MB. System requirements: Mac; Word. This technical report has been developed to address the survivability of telecommunications networks including services. It responds to the need for a common understanding of, and assessment techniques for network survivability, availability, integrity, and reliability. It provides a basis for designing and operating telecommunication networks to user expectations for network survivability.

  1. Depression and Liver Transplant Survival.

    Science.gov (United States)

    Meller, William; Welle, Nicole; Sutley, Kristen; Thurber, Steven

    Patients who underwent liver transplantation and experienced clinical depression have heretofore evinced lower survival rates when compared to nondepressed counterparts. To investigate the hypothesis that transplant patients who seek and obtain medical treatment for depression would circumvent the prior reduced survival findings. A total of 765 patients with liver transplants were scrutinized for complications following transplantation. Further, 104 patients experienced posttransplant depression as manifested by diagnosis and treatment by medical personnel. Survival analyses were conducted comparing hazard and survival curves for these selected individuals and the remainder of transplant patients. Contrary to prior data and consistent with the aforementioned hypothesis, median survival durations, survival curves, and hazard functions (controlling for age and prolonged posttransplant survival for the depressed patients were better. The improved survival for the depressed patients may simply be related to an amelioration of depressed symptoms via antidepressant medications. However, this interpretation would only be congruent with reduced hazard, not elevated survival, beyond the norm (median) for other transplant participants. Assuming the reliability and generalization of our findings, perhaps a reasonable and compelling interpretation is that combined with the effectiveness of antidepressant medications, the seeking and receiving treatment for depression is a type of proxy measure of a more global pattern of adherence to recommended posttransplant medical regimens. Copyright © 2017 The Academy of Psychosomatic Medicine. Published by Elsevier Inc. All rights reserved.

  2. Ship Systems Survivability Test Site

    Data.gov (United States)

    Federal Laboratory Consortium — Area for testing survivability of shipboard systems to include electrical, communications, and fire suppression. Multipurpose test range for supporting gun firing,...

  3. Surviving a Suicide Attempt

    Directory of Open Access Journals (Sweden)

    Ahmed Al-Harrasi

    2016-09-01

    Full Text Available Suicide is a global phenomenon in all regions of the world affecting people of all age groups. It has detrimental consequences on patients, their families, and the community as a whole. There have been numerous risk factors described for suicide including mental illness, stressful life situations, loss of social support, and general despair. The association of suicide with Islam has not been extensively studied. The common impression from clinical practice is that being a practicing Muslim reduces the risk of suicide. Another factor associated with suicide is starting a patient on antidepressants. However, this has been questioned recently. This report describes a middle-aged man with depression and multiple social stressors who survived a serious suicide attempt. The discussion will focus on the factors that lead him to want to end his life and the impact of the assumed protective factors such as religious belief and family support on this act of self-harm. Such patients can be on the edge when there is an imbalance between risk factors (such as depression, insomnia, and psychosocial stressors and protective factors (like religious affiliation and family support. All physicians are advised to assess the suicide risk thoroughly in patients with depression regardless of any presumed protective factor.

  4. Survival and weak chaos.

    Science.gov (United States)

    Nee, Sean

    2018-05-01

    Survival analysis in biology and reliability theory in engineering concern the dynamical functioning of bio/electro/mechanical units. Here we incorporate effects of chaotic dynamics into the classical theory. Dynamical systems theory now distinguishes strong and weak chaos. Strong chaos generates Type II survivorship curves entirely as a result of the internal operation of the system, without any age-independent, external, random forces of mortality. Weak chaos exhibits (a) intermittency and (b) Type III survivorship, defined as a decreasing per capita mortality rate: engineering explicitly defines this pattern of decreasing hazard as 'infant mortality'. Weak chaos generates two phenomena from the normal functioning of the same system. First, infant mortality- sensu engineering-without any external explanatory factors, such as manufacturing defects, which is followed by increased average longevity of survivors. Second, sudden failure of units during their normal period of operation, before the onset of age-dependent mortality arising from senescence. The relevance of these phenomena encompasses, for example: no-fault-found failure of electronic devices; high rates of human early spontaneous miscarriage/abortion; runaway pacemakers; sudden cardiac death in young adults; bipolar disorder; and epilepsy.

  5. A survival programme

    International Nuclear Information System (INIS)

    Vester, F.

    1978-01-01

    The book is a non-speculative information source on ecological problems and their possible solutions. It is a 'programme' from a twofold point of view: it determines political and scientific-technological objectives and it transfers knowledge by mental steps with techniques of programmed instruction. Thus emphasis is laid on detailed problems, especially by conscionsly challenged redundancies, and, on the other hand, a greater context is presented. Selected facts are examined under their different aspects, interactions and control circuits are described. Each chapter will speak for itself after the introduction has been read but is related to other chapters by cross references, illustrative material, a glossary and a comprehensive list of references. The 'Survival Programme' is a realistic and challenging discussion with the problem of 'Ecology in the Industrial Age'. It adresses scientists from various disciplines but also offers itself as a compendium to laymen in search of information, members of citizens initiatives and responsible representants of the political and industrial world. (orig./HP) [de

  6. Interactions between intestinal pathogens, enteropathy and malnutrition in developing countries.

    Science.gov (United States)

    Prendergast, Andrew J; Kelly, Paul

    2016-06-01

    This review focuses on recent data highlighting the interactions between intestinal pathogens, enteropathy and malnutrition in developing countries, which drive morbidity and mortality and hinder the long-term developmental potential of children. Diarrhoea remains the second commonest cause of death in children below 5 years, and malnutrition underlies 45% of all child deaths. Even in the absence of diarrhoea, subclinical pathogen carriage and enteropathy are almost universal in developing countries. Here, we review recent studies addressing the causes and consequences of diarrhoea; emerging data on environmental influences that govern postnatal development of the gut and microbiota; current concepts of environmental enteric dysfunction; and recent intervention trials in the field. We highlight the interactions between these processes, whereby intestinal pathogens drive a cycle of gut damage, malabsorption, chronic inflammation and failed mucosal regeneration, leading to malnutrition and susceptibility to further enteric infections. Efforts to improve child survival and long-term developmental potential need to address the overlapping and interacting effects of diarrhoea, enteropathy and malnutrition. Recent insights from human and animal studies suggest potential targets for intervention.

  7. Epigenetic control of effectors in plant pathogens

    Directory of Open Access Journals (Sweden)

    Mark eGijzen

    2014-11-01

    Full Text Available Plant pathogens display impressive versatility in adapting to host immune systems. Pathogen effector proteins facilitate disease but can become avirulence (Avr factors when the host acquires discrete recognition capabilities that trigger immunity. The mechanisms that lead to changes to pathogen Avr factors that enable escape from host immunity are diverse, and include epigenetic switches that allow for reuse or recycling of effectors. This perspective outlines possibilities of how epigenetic control of Avr effector gene expression may have arisen and persisted in plant pathogens, and how it presents special problems for diagnosis and detection of specific pathogen strains or pathotypes.

  8. Vibrio harveyi effect under survival of Litopenaeus vannamei larvae

    Directory of Open Access Journals (Sweden)

    Gabriel Aguirre-Guzmán

    2013-06-01

    Full Text Available The culture of aquatic organisms show a high relevance in the human feeding and the culture activities can create artificial conditions that increase the growth and selection of specific bacteria. Vibrio species are normal bacteria’s from microflora of penaeid shrimp, those are opportunistic pathogens that can take advantage of the ecological changes generated for the culture of aquatic organisms and which may cause diseases, low survival and economic losses in the shrimp production. The aim of this research was to determine the variation in the survival of different larval substages (nauplius, zoea I-III, mysis I-III and postlarvae 1, of Pacific white shrimp Litopenaeus vannamei exposed at three doses [103 , 105 , and 107 colony-forming unit (CFU ml-1 [ of V. harveyi, by immersion (30 min as infection method. This species generated a significant low survival in larvae (p < 0.05 only in high doses (105 and 107 CFU ml-1 , where higher doses show the lowest values of survival. Larval substages and postlarvae 1 of shrimp showed sensitivity associate to the increase of Vibrio doses and this sensitivity decreased with the growth of larval substages and postlarvae 1. This information has high significance for the fisheries and aquaculture industry, which help to generate strategies to reduce the effects of V. harveyi with positive effect in growth and survival of the shrimp larvae and postlarvae 1.

  9. Pathogen recognition in the innate immune response.

    Science.gov (United States)

    Kumar, Himanshu; Kawai, Taro; Akira, Shizuo

    2009-04-28

    Immunity against microbial pathogens primarily depends on the recognition of pathogen components by innate receptors expressed on immune and non-immune cells. Innate receptors are evolutionarily conserved germ-line-encoded proteins and include TLRs (Toll-like receptors), RLRs [RIG-I (retinoic acid-inducible gene-I)-like receptors] and NLRs (Nod-like receptors). These receptors recognize pathogens or pathogen-derived products in different cellular compartments, such as the plasma membrane, the endosomes or the cytoplasm, and induce the expression of cytokines, chemokines and co-stimulatory molecules to eliminate pathogens and instruct pathogen-specific adaptive immune responses. In the present review, we will discuss the recent progress in the study of pathogen recognition by TLRs, RLRs and NLRs and their signalling pathways.

  10. Contamination of water resources by pathogenic bacteria

    Science.gov (United States)

    2014-01-01

    Water-borne pathogen contamination in water resources and related diseases are a major water quality concern throughout the world. Increasing interest in controlling water-borne pathogens in water resources evidenced by a large number of recent publications clearly attests to the need for studies that synthesize knowledge from multiple fields covering comparative aspects of pathogen contamination, and unify them in a single place in order to present and address the problem as a whole. Providing a broader perceptive of pathogen contamination in freshwater (rivers, lakes, reservoirs, groundwater) and saline water (estuaries and coastal waters) resources, this review paper attempts to develop the first comprehensive single source of existing information on pathogen contamination in multiple types of water resources. In addition, a comprehensive discussion describes the challenges associated with using indicator organisms. Potential impacts of water resources development on pathogen contamination as well as challenges that lie ahead for addressing pathogen contamination are also discussed. PMID:25006540

  11. Icu Pathogens: A Continuous Challenge

    International Nuclear Information System (INIS)

    Hafeez, A.; Munir, T.; Najeeb, S.; Rehman, S.; Gilani, M.

    2016-01-01

    Objective: To determine the frequency and antibiogram of pathogens in an intensive care unit (ICU). Study Design: Cross-sectional, observational study. Place and Duration of Study: Department of Microbiology, Army Medical College, National University of Science and Technology, Islamabad, from January 2013 to January 2014. Methodology: Clinical samples, received from patients admitted in ICU, were inoculated on various medias like blood agar, chocolate agar, MacConkey agar and urine samples on CLED. These were then incubated at 37 degree C for 24 hours. Isolates were identified by colony morphology, Gram reaction, catalase test, oxidase test. Species identification in case of Gram Negative Rods was done by using API 20E (BioMerieux). Antibiotic susceptibility was done by using modified KirbyBauer disc diffusion technique. Bacterial isolates were prepared and inoculated on Mueller-Hinton agar plates followed by application of various antibiotic disc (Oxoid, UK) as per manufacturer's instructions. The plates were then incubated at 37 degree C aerobically for 18 - 24 hours. Zone diameters were measured and interpreted as sensitive and resistant, according to Clinical and Laboratory Standards Institute (CLSI) guidelines. Results: Out of the 367 positive cultures, 116 (31.08 percent) were Acinetobacter baumanniisusceptible to minocycline and tigecycline followed by Klebsiella pneumoniae (n=71, 16 percent) susceptible to tigecycline and meropenem. Others were Pseudomonas aeruginosa, Escherichia coli Coagulase Negative Staphylococcus, Staphylococcus aureus, Enterococcus spp., Streptococcus spp., Klebsiella oxytoca, Stenotrophomonas maltophilia, and Candida spp. Conclusion: Acinetobacter baumannii was the most frequently isolated pathogen. Most of the cultures yielding pathogens were from respiratory tract samples. Gram negative isolates were multidrug resistant but most were tigecycline and susceptible to meropenem. (author)

  12. The role and regulation of catalase in respiratory tract opportunistic bacterial pathogens.

    Science.gov (United States)

    Eason, Mia M; Fan, Xin

    2014-09-01

    Respiratory tract bacterial pathogens are the etiologic agents of a variety of illnesses. The ability of these bacteria to cause disease is imparted through survival within the host and avoidance of pathogen clearance by the immune system. Respiratory tract pathogens are continually bombarded by reactive oxygen species (ROS), which may be produced by competing bacteria, normal metabolic function, or host immunological responses. In order to survive and proliferate, bacteria have adapted defense mechanisms to circumvent the effects of ROS. Bacteria employ the use of anti-oxidant enzymes, catalases and catalase-peroxidases, to relieve the effects of the oxidative stressors to which they are continually exposed. The decomposition of ROS has been shown to provide favorable conditions in which respiratory tract opportunistic bacterial pathogens such as Haemophilus influenzae, Mycobacterium tuberculosis, Legionella pneumophila, and Neisseria meningitidis are able to withstand exposure to highly reactive molecules and yet survive. Bacteria possessing mutations in the catalase gene have a decreased survival rate, yet may be able to compensate for the lack of catalatic activity if peroxidatic activity is present. An incomplete knowledge of the mechanisms by which catalase and catalase-peroxidases are regulated still persists, however, in some bacterial species, a regulatory factor known as OxyR has been shown to either up-regulate or down-regulate catalase gene expression. Yet, more research is still needed to increase the knowledge base in relation to this enzyme class. As with this review, we focus on major respiratory tract opportunistic bacterial pathogens in order to elucidate the function and regulation of catalases. The importance of the research could lead to the development of novel treatments against respiratory bacterial infections. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. The Arrhenius Equation As Means to Simulate E. Coli Survival in Waters

    Science.gov (United States)

    E. coli is an important microorganism indicator used to show the presence of pathogens and fecal contamination in waters. Knowing E. coli survival rates is important for assessing the severity of contamination that has occurred and making appropriate management evaluations. E. ...

  14. Survival of Phytophthora ramorum in Rhododendron root balls and in rootless substrates

    Science.gov (United States)

    A. Vercauteren; M. Riedel; M. Maes; S. Werres; K. Heungens

    2013-01-01

    This study assesses the survival of Phytophthora ramorum in the root ball of Rhododendron container plants as well as in different rootless forest substrates and a horticultural potting medium. Following inoculation of the root balls, the aboveground plant parts stayed symptomless, whilst the pathogen could be recovered with a...

  15. Global Activities and Plant Survival

    DEFF Research Database (Denmark)

    Bandick, Roger

    2014-01-01

    the highest exit rates. Moreover, the exit rates of globally engaged plants seem to be unaffected by increased foreign presence, whereas there appears to be a negative impact on the survival rates of non-exporting non-MNE plants. Finally, the result reveals that the survival ratio of plants of acquired...

  16. Radionuclide blood cell survival studies

    International Nuclear Information System (INIS)

    Bentley, S.A.; Miller, D.T.

    1986-01-01

    Platelet and red cell survival studies are reviewed. The use of 51 Cr and di-isopropylfluoridate labelled with tritium or 32 P is discussed for red cell survival study and 51 Cr and 111 In-oxine are considered as platelet labels. (UK)

  17. Female partner preferences enhance offspring ability to survive an infection.

    Science.gov (United States)

    Raveh, Shirley; Sutalo, Sanja; Thonhauser, Kerstin E; Thoß, Michaela; Hettyey, Attila; Winkelser, Friederike; Penn, Dustin J

    2014-01-23

    It is often suggested that mate choice enhances offspring immune resistance to infectious diseases. To test this hypothesis, we conducted a study with wild-derived house mice (Mus musculus musculus) in which females were experimentally mated either with their preferred or non-preferred male, and their offspring were infected with a mouse pathogen, Salmonella enterica (serovar Typhimurium). We found that offspring sired by preferred males were significantly more likely to survive the experimental infection compared to those sired by non-preferred males. We found no significant differences in the pathogen clearance or infection dynamics between the infected mice, suggesting that offspring from preferred males were better able to cope with infection and had improved tolerance rather than immune resistance. Our results provide the first direct experimental evidence within a single study that partner preferences enhance offspring resistance to infectious diseases.

  18. Mycoplasmas and their host: emerging and re-emerging minimal pathogens.

    Science.gov (United States)

    Citti, Christine; Blanchard, Alain

    2013-04-01

    Commonly known as mycoplasmas, bacteria of the class Mollicutes include the smallest and simplest life forms capable of self replication outside of a host. Yet, this minimalism hides major human and animal pathogens whose prevalence and occurrence have long been underestimated. Owing to advances in sequencing methods, large data sets have become available for a number of mycoplasma species and strains, providing new diagnostic approaches, typing strategies, and means for comprehensive studies. A broader picture is thus emerging in which mycoplasmas are successful pathogens having evolved a number of mechanisms and strategies for surviving hostile environments and adapting to new niches or hosts. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. The response of foodborne pathogens to osmotic and desiccation stresses in the food chain

    DEFF Research Database (Denmark)

    Burgess, Catherine M.; Gianotti, Andrea; Gruzdev, Nadia

    2016-01-01

    In combination with other strategies, hyperosmolarity and desiccation are frequently used by the food processing industry as a means to prevent bacterial proliferation, and particularly that of foodborne pathogens, in food products. However, it is increasingly observed that bacteria, including...... human pathogens, encode mechanisms to survive and withstand these stresses. This review provides an overview of the mechanisms employed by Salmonella spp., Shiga toxin producing E. coli, Cronobacter spp., Listeria monocytogenes and Campylobacter spp. to tolerate osmotic and desiccation stresses...... and identifies gaps in knowledge which need to be addressed to ensure the safety of low water activity and desiccated food products....

  20. Plant pathogenic anaerobic bacteria use aromatic polyketides to access aerobic territory.

    Science.gov (United States)

    Shabuer, Gulimila; Ishida, Keishi; Pidot, Sacha J; Roth, Martin; Dahse, Hans-Martin; Hertweck, Christian

    2015-11-06

    Around 25% of vegetable food is lost worldwide because of infectious plant diseases, including microbe-induced decay of harvested crops. In wet seasons and under humid storage conditions, potato tubers are readily infected and decomposed by anaerobic bacteria (Clostridium puniceum). We found that these anaerobic plant pathogens harbor a gene locus (type II polyketide synthase) to produce unusual polyketide metabolites (clostrubins) with dual functions. The clostrubins, which act as antibiotics against other microbial plant pathogens, enable the anaerobic bacteria to survive an oxygen-rich plant environment. Copyright © 2015, American Association for the Advancement of Science.

  1. Damage by pathogens and insects to Scots pine and lodgepole pine 25 years after reciprocal plantings in Canada and Sweden

    OpenAIRE

    Fries, Anders

    2017-01-01

    A combined species - provenance - family experiment with Scots pine and lodgepole pine was planted in Canada and Sweden. One aim of the experiment was to evaluate the two species' sensitivities to pathogens and insects 25 years after establishment in their non-native continents. In Canada, Scots pine had better average survival than lodgepole pine, but survival rates among trees from the best seed-lots were equal. In Canada only western gall rust infected Scots pine to some extent, and mounta...

  2. Salmonella Pathogenicity and Host Adaptation in Chicken-Associated Serovars

    Science.gov (United States)

    Johnson, Timothy J.; Ricke, Steven C.; Nayak, Rajesh; Danzeisen, Jessica

    2013-01-01

    SUMMARY Enteric pathogens such as Salmonella enterica cause significant morbidity and mortality. S. enterica serovars are a diverse group of pathogens that have evolved to survive in a wide range of environments and across multiple hosts. S. enterica serovars such as S. Typhi, S. Dublin, and S. Gallinarum have a restricted host range, in which they are typically associated with one or a few host species, while S. Enteritidis and S. Typhimurium have broad host ranges. This review examines how S. enterica has evolved through adaptation to different host environments, especially as related to the chicken host, and continues to be an important human pathogen. Several factors impact host range, and these include the acquisition of genes via horizontal gene transfer with plasmids, transposons, and phages, which can potentially expand host range, and the loss of genes or their function, which would reduce the range of hosts that the organism can infect. S. Gallinarum, with a limited host range, has a large number of pseudogenes in its genome compared to broader-host-range serovars. S. enterica serovars such as S. Kentucky and S. Heidelberg also often have plasmids that may help them colonize poultry more efficiently. The ability to colonize different hosts also involves interactions with the host's immune system and commensal organisms that are present. Thus, the factors that impact the ability of Salmonella to colonize a particular host species, such as chickens, are complex and multifactorial, involving the host, the pathogen, and extrinsic pressures. It is the interplay of these factors which leads to the differences in host ranges that we observe today. PMID:24296573

  3. Streptococcus agalactiae: a vaginal pathogen?

    Science.gov (United States)

    Maniatis, A N; Palermos, J; Kantzanou, M; Maniatis, N A; Christodoulou, C; Legakis, N J

    1996-03-01

    The significance of Streptococcus agalactiae as an aetiological agent in vaginitis was evaluated. A total of 6226 samples from women who presented with vaginal symptoms was examined. The presence of >10 leucocytes/high-power field (h.p.f.) was taken to be the criterion of active infection. S. agalactiae was isolated from 10.1% of these samples. The isolation rates of other common pathogens such as Candida spp., Gardnerella vaginalis and Trichomonas spp. were 54.1%, 27.2% and 4.2%, respectively, in the same group of patients. In contrast, the isolation rates of these micro-organisms in the group of patients who had no infection (S. agalactiae was isolated, it was the sole pathogen isolated (83%) and its presence was associated with an inflammatory response in 80% of patients. Furthermore, the relative risk of vaginal infection with S. agalactiae (2.38) in patients with purulent vaginal discharge was greater than that of Candida spp. infection (1.41) and lower than that of Trichomonas spp. infection (8.32). These data suggest that S. agalactiae in symptomatic women with microscopic evidence of inflammation should be considered a causative agent of vaginitis.

  4. Boosted TCA cycle enhances survival of zebrafish to Vibrio alginolyticus infection.

    Science.gov (United States)

    Yang, Man-Jun; Cheng, Zhi-Xue; Jiang, Ming; Zeng, Zao-Hai; Peng, Bo; Peng, Xuan-Xian; Li, Hui

    2018-01-01

    Vibrio alginolyticus is a waterborne pathogen that infects a wide variety of hosts including fish and human, and the outbreak of this pathogen can cause a huge economic loss in aquaculture. Thus, enhancing host's capability to survive from V. alginolyticus infection is key to fighting infection and this remains still unexplored. In the present study, we established a V. alginolyticus-zebrafish interaction model by which we explored how zebrafish survived from V. alginolyticus infection. We used GC-MS based metabolomic approaches to characterize differential metabolomes between survival and dying zebrafish upon infection. Pattern recognition analysis identified the TCA cycle as the most impacted pathway. The metabolites in the TCA cycle were decreased in the dying host, whereas the metabolites were increased in the survival host. Furthermore, the enzymatic activities of the TCA cycle including pyruvate dehydrogenase (PDH), α-ketoglutaric dehydrogenase (KGDH) and succinate dehydrogenase (SDH) also supported this conclusion. Among the increased metabolites in the TCA cycle, malic acid was the most crucial biomarker for fish survival. Indeed, exogenous malate promoted zebrafish survival in a dose-dependent manner. The corresponding activities of KGDH and SDH were also increased. These results indicate that the TCA cycle is a key pathway responsible for the survival or death in response to infection caused by V. alginolyticus, and highlight the way on development of metabolic modulation to control the infection.

  5. Interaction of pathogens with host cholesterol metabolism.

    Science.gov (United States)

    Sviridov, Dmitri; Bukrinsky, Michael

    2014-10-01

    Pathogens of different taxa, from prions to protozoa, target cellular cholesterol metabolism to advance their own development and to impair host immune responses, but also causing metabolic complications, for example, atherosclerosis. This review describes recent findings of how pathogens do it. A common theme in interaction between pathogens and host cholesterol metabolism is pathogens targeting lipid rafts of the host plasma membrane. Many intracellular pathogens use rafts as an entry gate, taking advantage of the endocytic machinery and high abundance of outward-looking molecules that can be used as receptors. At the same time, disruption of the rafts' functional capacity, achieved by the pathogens through a number of various means, impairs the ability of the host to generate immune response, thus helping pathogen to thrive. Pathogens cannot synthesize cholesterol, and salvaging host cholesterol helps pathogens build advanced cholesterol-containing membranes and assembly platforms. Impact on cholesterol metabolism is not limited to the infected cells; proteins and microRNAs secreted by infected cells affect lipid metabolism systemically. Given an essential role that host cholesterol metabolism plays in pathogen development, targeting this interaction may be a viable strategy to fight infections, as well as metabolic complications of the infections.

  6. Marketing child survival.

    Science.gov (United States)

    Grant, J P

    1984-01-01

    Growth monitoring charts, packets of oral rehydration salts (ORS), and vaccines, are inexpensive, life-saving, growth-protecting technologies which can enable parents to protect their children against the worst effects of poverty. Similarly, a matrix of current and easily understandable information about pregnancy, breast feeding, weaning, feeding during and immediately after illness, child spacing, and preparing and using home-made oral rehydration solutions, also could empower parents to protect the lives and the health of their children. The question arises as to how can these technologies and this information be put at the disposal of millions of families in the low-income world. The initial task of the Child Survival and Development Revolution is the communication of what is now possible, yet little is known about how to communicate information whose principal value is to the poor. There are 2 large-scale precedents: the Green Revolution, which in many instances succeeded in putting into the hands of thousands of small and large farmers the techniques and the knowledge which enabled them to double and treble the yields from their lands; and the campaign to put the knowledge and the means of family planning at the disposal of many millions of people. There are 2 lessons to be learned from these precedents: they have shown that the way to promote a people's technology and to put information at the disposal of the majority is by mobilizing all possible resources and working through all possible channels both to create the demand and to meet it; and neither the Green Revolution nor the family planning movement rally took off until they were viewed as political and economic priorities and given the full support of the nation's political leadership. Nowhere are these 2 lessons more clearly illustrated than in present-day Indonesia. Because the campaign for family planning was given high personal and political priority by the President, and because 85% of all family

  7. Potentially pathogenic, pathogenic, and allergenic moulds in the urban soils

    Directory of Open Access Journals (Sweden)

    Đukić Dragutin A.

    2011-01-01

    Full Text Available The dynamics of soil mould populations that can compromise the human immune system was evaluated in experimental plots located at different distances (100, 300, 500, 700 and 900 m from the main source of pollution - the Podgorica Aluminum Plant. Soil samples were collected in July and October 2008 from three different plot zones at a depth of 0-10 cm. The count of potentially pathogenic, keratinolytic and allergenic (melaninogenic moulds was assessed, which can significantly contribute to both diagnosis and prophylaxis. The count of medically important moulds was higher in the urban soil than in the unpolluted (control soil. Their count decreased with increasing distance from the main pollution source (PAP. Their abundance in the soil was considerably higher in autumn than in spring.

  8. Genetic characteristics and pathogenic mechanisms of periodontal pathogens.

    Science.gov (United States)

    Amano, A; Chen, C; Honma, K; Li, C; Settem, R P; Sharma, A

    2014-05-01

    Periodontal disease is caused by a group of bacteria that utilize a variety of strategies and molecular mechanisms to evade or overcome host defenses. Recent research has uncovered new evidence illuminating interesting aspects of the virulence of these bacteria and their genomic variability. This paper summarizes some of the strategies utilized by the major species - Aggregatibacter actinomycetemcomitans, Tannerella forsythia, Treponema denticola, and Porphyromonas gingivalis - implicated in the pathogenesis of periodontal disease. Whole-genome sequencing of 14 diverse A. actinomycetemcomitans strains has revealed variations in their genetic content (ranging between 0.4% and 19.5%) and organization. Strikingly, isolates from human periodontal sites showed no genomic changes during persistent colonization. T. forsythia manipulates the cytokine responses of macrophages and monocytes through its surface glycosylation. Studies have revealed that bacterial surface-expressed O-linked glycans modulate T-cell responses during periodontal inflammation. Periodontal pathogens belonging to the "red complex" consortium express neuraminidases, which enables them to scavenge sialic acid from host glycoconjugates. Analysis of recent data has demonstrated that the cleaved sialic acid acts as an important nutrient for bacterial growth and a molecule for the decoration of bacteria surfaces to help evade the host immune attack. In addition, bacterial entry into host cells is also an important prerequisite for the lifestyle of periodontal pathogens such as P. gingivalis. Studies have shown that, after its entry into the cell, this bacterium uses multiple sorting pathways destined for autophagy, lysosomes, or recycling pathways. In addition, P. gingivalis releases outer membrane vesicles which enter cells via endocytosis and cause cellular functional impairment.

  9. Competitive Survival of Escherichia coli, Vibrio cholerae, Salmonella typhimurium and Shigella dysenteriae in Riverbed Sediments.

    Science.gov (United States)

    Abia, Akebe Luther King; Ubomba-Jaswa, Eunice; Momba, Maggy Ndombo Benteke

    2016-11-01

    Studies on the survival of bacterial enteric pathogens in riverbed sediments have mostly focused on individual organisms. Reports on the competitive survival of these pathogens in riverbed sediments under the same experimental setup are limited. We investigated the survival of Escherichia coli, Salmonella enterica ser. Typhimurium, Vibrio cholerae and Shigella dysenteriae in riverbed sediments of the Apies River. Experiments were performed in flow chambers containing three sediment types and connected to aquarium pumps immersed in river water to maintain continuous water circulation. Each chamber was inoculated with ~10 7  CFU/mL (final concentration) of each microorganism and kept at 4, 20 and 30 °C. Chambers were sampled on days 0, 1, 2, 7, 14 and 28. At 4 °C, only E. coli and S. typhimurium survived throughout the 28 experimental days. V. cholerae had the shortest survival time at this temperature and was not detected in any of the sediment chambers 24 h after inoculation. S. dysenteriae only survived until day 7. At an increased temperature of 20 °C, only S. dysenteriae was not detected on day 28 of the experiment. At 30 °C, V. cholerae and Salmonella survived longer (28 days) than E. coli (14 days) and S. dysenteriae (4 days). Vibrio cholerae was shown to have the highest T 90 values (32 days) in all sediment types at 20 and 30 °C. We conclude that the sediments of the Apies River present a favourable environment for the survival of indicator and pathogenic bacteria depending on the prevailing temperature.

  10. Mucosal immunity to pathogenic intestinal bacteria.

    Science.gov (United States)

    Perez-Lopez, Araceli; Behnsen, Judith; Nuccio, Sean-Paul; Raffatellu, Manuela

    2016-03-01

    The intestinal mucosa is a particularly dynamic environment in which the host constantly interacts with trillions of commensal microorganisms, known as the microbiota, and periodically interacts with pathogens of diverse nature. In this Review, we discuss how mucosal immunity is controlled in response to enteric bacterial pathogens, with a focus on the species that cause morbidity and mortality in humans. We explain how the microbiota can shape the immune response to pathogenic bacteria, and we detail innate and adaptive immune mechanisms that drive protective immunity against these pathogens. The vast diversity of the microbiota, pathogens and immune responses encountered in the intestines precludes discussion of all of the relevant players in this Review. Instead, we aim to provide a representative overview of how the intestinal immune system responds to pathogenic bacteria.

  11. Yeast cell differentiation: Lessons from pathogenic and non-pathogenic yeasts.

    Science.gov (United States)

    Palková, Zdena; Váchová, Libuše

    2016-09-01

    Yeasts, historically considered to be single-cell organisms, are able to activate different differentiation processes. Individual yeast cells can change their life-styles by processes of phenotypic switching such as the switch from yeast-shaped cells to filamentous cells (pseudohyphae or true hyphae) and the transition among opaque, white and gray cell-types. Yeasts can also create organized multicellular structures such as colonies and biofilms, and the latter are often observed as contaminants on surfaces in industry and medical care and are formed during infections of the human body. Multicellular structures are formed mostly of stationary-phase or slow-growing cells that diversify into specific cell subpopulations that have unique metabolic properties and can fulfill specific tasks. In addition to the development of multiple protective mechanisms, processes of metabolic reprogramming that reflect a changed environment help differentiated individual cells and/or community cell constituents to survive harmful environmental attacks and/or to escape the host immune system. This review aims to provide an overview of differentiation processes so far identified in individual yeast cells as well as in multicellular communities of yeast pathogens of the Candida and Cryptococcus spp. and the Candida albicans close relative, Saccharomyces cerevisiae. Molecular mechanisms and extracellular signals potentially involved in differentiation processes are also briefly mentioned. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Cardiovascular disease incidence and survival

    DEFF Research Database (Denmark)

    Byberg, Stine; Agyemang, Charles; Zwisler, Ann Dorthe

    2016-01-01

    Studies on cardiovascular disease (CVD) incidence and survival show varying results between different ethnic groups. Our aim was to add a new dimension by exploring the role of migrant status in combination with ethnic background on incidence of-and survival from-CVD and more specifically acute...... of some types of cardiovascular disease compared to Danish-born. Family-reunified migrants on the other hand had lower rates of CVD. All migrants had better survival than Danish-born indicating that migrants may not always be disadvantaged in health....

  13. Stimulated human fibroblast cell survival

    International Nuclear Information System (INIS)

    Smith, B.P.; Gale, K.L.; Einspenner, M.; Greenstock, C.L.; Gentner, N.E.

    1992-01-01

    Techniques for cloning cultured mammalian cells have supported the most universally-accepted method for measuring the induction of lethality by geno-toxicants such as ionizing radiation: the 'survival of colony-forming ability (CFA)' assay. Since most cultured human cell lines exhibit plating efficiency (i.e. the percentage of cells that are capable of reproductively surviving and dividing to form visible colonies) well below 100%, such assays are in essence 'survival of plating efficiency' assays, since they are referred to the plating (or cloning) efficiency of control (i.e. unirradiated) cells. (author). 8 refs., 2 figs

  14. Survival of pathogens of Brussels sprouts (Brassica oleracea Gemifera group) in crop residues

    NARCIS (Netherlands)

    Köhl, J.; Vlaswinkel, M.E.T.; Groenenboom-de Haas, B.H.; Kastelein, P.; Hoof, van R.A.; Wolf, van der J.M.; Krijger, M.C.

    2011-01-01

    Mycosphaerella brassicicola (ringspot), Alternaria brassicicola and A. brassicae (dark leaf spot) and Xanthomonas campestris pv. campestris (black spot) can infect leaves of Brussels sprouts resulting in yield losses. Infections of outer leaves of sprouts cause severe losses in quality. Crop

  15. Persistence and survival of pathogens in dry foods and dry food processing environments

    NARCIS (Netherlands)

    Beuchat, L.; Komitopoulou, E.; Betts, R.; Beckers, H.; Bourdichon, F.; Joosten, H.; Fanning, S.; ter Kuile, B.

    2011-01-01

    Low-moisture foods and food ingredients, i.e., those appearing to be dry or that have been subjected to a drying process, represent important nutritional constituents of human diets. Some of these foods are naturally low in moisture, such as cereals, honey and nuts, whereas others are produced from

  16. Biology of the fire blight pathogen Erwinia amylovora in oligotrophic environments: survival responses and virulence

    OpenAIRE

    Delgado Santander, Ricardo

    2016-01-01

    Erwinia amylovora es una bacteria fitopatógena de la familia Enterobacteriaceae, responsable del fuego bacteriano de las rosáceas. Los efectos destructivos de este patógeno sobre frutos, flores y prácticamente todos los órganos de las plantas hospedadoras afectadas constituyen una amenaza importante para la producción de pera y manzana, y suponen graves pérdidas económicas anuales en todo el mundo. E. amylovora está clasificada como un organismo de cuarentena en la Unión Europea y en otros pa...

  17. Effect of peppermint essential oil on growth and survival of some foodborne pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    M Boniadian

    2014-08-01

    Full Text Available This study was conducted to determine the effects of peppermint essential oils on Bacillus cereus, Salmonella typhimurium, Listeria monocytogenes and Yersinia enterocolitica. In the first step, Minimum Inhibitory Concentration (MIC and Minimum Bactericidal Concentration (MBC of peppermint essential were determined by the tube dilution method in tryptic soy broth (TSB. Then, the growth behavior of each of the aforementioned bacteria was assessed in presence of peppermint essential oil in concentration of less than MIC. The result of first step showed that Y. enterocolitica is more sensitive to peppermint essential oil than other tested bacteria (MIC = 0.1% & MBC = 0.22%, followed by L. monocytogenes (MIC = 0.12% & MBC = 0.15%, S. typhimurium (MIC = 0.22% & MBC = 0.25% and B. cereus (MIC = 0.3% & MBC = 5%, respectively. The results revealed that, the peppermint essential oils in low concentration inhibited the growth rate of bacteria thus may use as a natural preservative and flavoring in foods.

  18. Heme Synthesis and Acquisition in Bacterial Pathogens

    OpenAIRE

    Choby, Jacob E.; Skaar, Eric P.

    2016-01-01

    Bacterial pathogens require the iron-containing cofactor heme to cause disease. Heme is essential to the function of hemoproteins, which are involved in energy generation by the electron transport chain, detoxification of host immune effectors, and other processes. During infection, bacterial pathogens must synthesize heme or acquire heme from the host; however, host heme is sequestered in high-affinity hemoproteins. Pathogens have evolved elaborate strategies to acquire heme from host source...

  19. The Candida Pathogenic Species Complex

    Science.gov (United States)

    Turner, Siobhán A.; Butler, Geraldine

    2014-01-01

    Candida species are the most common causes of fungal infection. Approximately 90% of infections are caused by five species: Candida albicans, Candida glabrata, Candida tropicalis, Candida parapsilosis, and Candida krusei. Three (C. albicans, C. tropicalis, and C. parapsilosis) belong to the CTG clade, in which the CTG codon is translated as serine and not leucine. C. albicans remains the most commonly isolated but is decreasing relative to the other species. The increasing incidence of C. glabrata is related to its reduced susceptibility to azole drugs. Genome analysis suggests that virulence in the CTG clade is associated with expansion of gene families, particularly of cell wall genes. Similar independent processes took place in the C. glabrata species group. Gene loss and expansion in an ancestor of C. glabrata may have resulted in preadaptations that enabled pathogenicity. PMID:25183855

  20. Land application of sewage sludge: Pathogen issues

    International Nuclear Information System (INIS)

    Chang, A.C.

    1997-01-01

    Diseases transmitted via the faecal-oral exposure route cause severe gastroenteric disorders, and large numbers of causative organisms are discharged with the faecal matter of infected individuals. For this reason, pathogenic bacteria, viruses, protozoa, or helminths, are always found in sewage sludge. If not properly treated for use in agriculture, sludge can be a source of pathogenic contamination. Radiation is an attractive method to reduce the numbers of microorganisms in sewage sludge. Routine examination for pathogens is not practised nor recommended because complicated and costly procedures are involved. Instead, an indicator organism is usually assayed and enumerated. In this paper, methods are discussed for the investigation of pathogens in sewage sludge. (author)

  1. Effects of co-occurring Wolbachia and Spiroplasma endosymbionts on the Drosophila immune response against insect pathogenic and non-pathogenic bacteria.

    Science.gov (United States)

    Shokal, Upasana; Yadav, Shruti; Atri, Jaishri; Accetta, Julia; Kenney, Eric; Banks, Katherine; Katakam, Akash; Jaenike, John; Eleftherianos, Ioannis

    2016-02-09

    Symbiotic interactions between microbes and animals are common in nature. Symbiotic organisms are particularly common in insects and, in some cases, they may protect their hosts from pathogenic infections. Wolbachia and Spiroplasma endosymbionts naturally inhabit various insects including Drosophila melanogaster fruit flies. Therefore, this symbiotic association is considered an excellent model to investigate whether endosymbiotic bacteria participate in host immune processes against certain pathogens. Here we have investigated whether the presence of Wolbachia alone or together with Spiroplasma endosymbionts in D. melanogaster adult flies affects the immune response against the virulent insect pathogen Photorhabdus luminescens and against non-pathogenic Escherichia coli bacteria. We found that D. melanogaster flies carrying no endosymbionts, those carrying both Wolbachia and Spiroplasma, and those containing Wolbachia only had similar survival rates after infection with P. luminescens or Escherichia coli bacteria. However, flies carrying both endosymbionts or Wolbachia only contained higher numbers of E. coli cells at early time-points post infection than flies without endosymbiotic bacteria. Interestingly, flies containing Wolbachia only had lower titers of this endosymbiont upon infection with the pathogen P. luminescens than uninfected flies of the same strain. We further found that the presence of Wolbachia and Spiroplasma in D. melanogaster up-regulated certain immune-related genes upon infection with P. luminescens or E. coli bacteria, but it failed to alter the phagocytic ability of the flies toward E. coli inactive bioparticles. Our results suggest that the presence of Wolbachia and Spiroplasma in D. melanogaster can modulate immune signaling against infection by certain insect pathogenic and non-pathogenic bacteria. Results from such studies are important for understanding the molecular basis of the interactions between endosymbiotic bacteria of insects

  2. Probabilistic Survivability Versus Time Modeling

    Science.gov (United States)

    Joyner, James J., Sr.

    2016-01-01

    This presentation documents Kennedy Space Center's Independent Assessment work completed on three assessments for the Ground Systems Development and Operations (GSDO) Program to assist the Chief Safety and Mission Assurance Officer during key programmatic reviews and provided the GSDO Program with analyses of how egress time affects the likelihood of astronaut and ground worker survival during an emergency. For each assessment, a team developed probability distributions for hazard scenarios to address statistical uncertainty, resulting in survivability plots over time. The first assessment developed a mathematical model of probabilistic survivability versus time to reach a safe location using an ideal Emergency Egress System at Launch Complex 39B (LC-39B); the second used the first model to evaluate and compare various egress systems under consideration at LC-39B. The third used a modified LC-39B model to determine if a specific hazard decreased survivability more rapidly than other events during flight hardware processing in Kennedy's Vehicle Assembly Building.

  3. The Survival of the Wisest

    Science.gov (United States)

    Salk, Jonas

    1975-01-01

    Suggests that humans differ from other living organisms in the ability to exercise learned behavior and the individual will, which may allow people to make the changes in values necessary to survive on this planet. (DW)

  4. Impact of relative humidity, inoculum carrier and size, and native microbiota on Salmonella ser. Typhimurium survival in baby lettuce.

    Science.gov (United States)

    López-Gálvez, Francisco; Gil, Maria Isabel; Allende, Ana

    2018-04-01

    The effects of relative humidity (RH), fluctuating climate conditions, inoculum size and carrier on the survival of Salmonella enterica serovar Typhimurium on baby lettuce in environmental test chambers were studied. Buffered peptone water (BPW), distilled water (DW), and irrigation water (IW) were compared as inoculum carriers. Additionally, survival of Salmonella in suspensions prepared using filtered and unfiltered IW was assessed. Salmonella Typhimurium survived better on baby lettuce plants at high RH independently of the inoculum size. When lettuce plants were grown under fluctuating environmental conditions, Salmonella survival was similar under both RH conditions. Regarding the inoculum carrier, the inoculated microorganism survived better on lettuce plants when BPW was used as carrier both at high and low RH. Survival rate of Salmonella in IW was affected by the presence of native microbiota. Native microbiota present in IW did not affect survival of Salmonella or the levels of mesophilic bacteria on the baby lettuce leaves. The information obtained in the present study contributes to the knowledge on the effect of environmental conditions on pathogenic bacteria survival on growing edible plants. These results are useful when selecting the methodology to carry out experimental studies on the survival of microbial pathogens under different pre-harvest conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Customer service skills for survival.

    Science.gov (United States)

    McAtee, L F

    1999-11-01

    As APICS practitioners, we all must share a common goal. How can we contribute to our company's success? Success can be measured in positive terms of market share, growth, profitability, return on investment, or some combination thereof. Each company must establish its own definition of success. For the purposes of this article, success will be equated to one word that we can all readily identify with: survival. What skills do we need to survive in the marketplace of the next millennium?

  6. Prolongation of islet allograft survival

    International Nuclear Information System (INIS)

    Lacy, P.E.; Davie, J.M.; Finke, E.H.; Scharp, D.W.

    1979-01-01

    Pretreatment of donor rats with irradiation and silica followed by in vitro culture of the islets for 1 to 2 days prolonged survival of allografts across a minor histocompatibility barrier if hand-picked, clean islets were used for transplantation. Pretreatment of donor rats with irradiation and silica in conjunction with a single injection of antilymphocyte serum (ALS) into the recipient produced a prolongation of survival of hand-picked islets transplanted across a major histocompatibility barrier

  7. Operational slack and venture survival

    OpenAIRE

    Azadegan, Arash; Patel, Pankaj; Parida, Vinit

    2013-01-01

    Slack can act as a double-edged sword. While it can buffer against environmental threats to help ensure business continuity, slack canalso be costly and reduce profitability. In this study, we focus on operational slack, the form related to the firm’s production processes. We investigate the role of operational slack on firm survival during its venture stage, when its survival is significantly challenged by environmental threats. Specifically, we explore how change in three types of environme...

  8. Influence of soil pathogens on early regeneration success of tropical trees varies between forest edge and interior.

    Science.gov (United States)

    Krishnadas, Meghna; Comita, Liza S

    2018-01-01

    Soil fungi are key mediators of negative density-dependent mortality in seeds and seedlings, and the ability to withstand pathogens in the shaded understory of closed-canopy forests could reinforce light gradient partitioning by tree species. For four species of tropical rainforest trees-two shade-tolerant and two shade-intolerant-we conducted a field experiment to examine the interactive effects of fungal pathogens, light, and seed density on germination and early seedling establishment. In a fully factorial design, seeds were sown into 1 m 2 plots containing soil collected from underneath conspecific adult trees, with plots assigned to forest edge (high light) or shaded understory, high or low density, and fungicide or no fungicide application. We monitored total seed germination and final seedling survival over 15 weeks. Shade-intolerant species were strongly constrained by light; their seedlings survived only at the edge. Fungicide application significantly improved seedling emergence and/or survival for three of the four focal species. There were no significant interactions between fungicide and seed density, suggesting that pathogen spread with increased aggregation of seeds and seedlings did not contribute to pathogen-mediated mortality. Two species experienced significant edge-fungicide interactions, but fungicide effects in edge vs. interior forest varied with species and recruitment stage. Our results suggest that changes to plant-pathogen interactions could affect plant recruitment in human-impacted forests subject to fragmentation and edge-effects.

  9. Agrochemicals indirectly increase survival of E. coli O157:H7 and indicator bacteria by reducing ecosystem services.

    Science.gov (United States)

    Staley, Zachery R; Rohr, Jason R; Senkbeil, Jacob K; Harwood, Valerie J

    Storm water and agricultural runoff frequently contain agrochemicals, fecal indicator bacteria (FIB), and zoonotic pathogens. Entry of such contaminants into aquatic ecosystems may affect ecology and human health. This study tested the hypothesis that the herbicide atrazine and the fungicide chlorothalonil indirectly affect the survival of FIB (Escherichia coli and Enterococcus faecalis) and a pathogen (E. coli O157:H7) by altering densities of protozoan predators or by altering competition from autochthonous bacteria. Streptomycin-resistant E. coli, En. faecalis, and E. coli O157:H7 were added to microcosms composed of Florida river water containing natural protozoan and bacterial populations. FIB, pathogen, and protozoan densities were monitored over six days. Known metabolic inhibitors, cycloheximide and streptomycin, were used to inhibit autochthonous protozoa or bacteria, respectively. The inhibitors made it possible to isolate the effects of predation or competition on survival of allochthonous bacteria, and each treatment increased the survival of FIB and pathogens. Chlorothalonil's effect was similar to that of cycloheximide, significantly reducing protozoan densities and elevating densities of FIB and pathogens relative to the control. Atrazine treatment did not affect protozoan densities, but, through an effect on competition, resulted in significantly greater densities of En. faecalis and E. coli O157:H7. Hence, by reducing predaceous protozoa and bacterial competitors that facilitate purifying water bodies of FIBs and human pathogens, chlorothalonil and atrazine indirectly diminished an ecosystem service of fresh water.

  10. Opportunities for mitigating pathogen contamination during on-farm food production.

    Science.gov (United States)

    Doyle, Michael P; Erickson, Marilyn C

    2012-01-16

    Fruits, vegetables, and meat are susceptible to contamination by foodborne pathogens at many points from production through preparation in the home. This review will largely highlight approaches and progress made in the last five years to address strategies to reduce pathogen contamination in animal production but will also touch on the emerging field of preharvest produce food safety. Mitigation strategies can be divided into those that address pathogen reduction in the environment and those that target reduction/elimination of pathogen contamination in animals or plants. The former strategy has been encompassed in studies evaluating sanitation treatments of facilities as well as in numerous epidemiologic risk assessment studies (both on-farm assessments and computer simulation models) that identify management practices that impact pathogen prevalence in animals. Interventions to significantly reduce pathogen exposure via feed or water are dependent on their role as a significant contributor to pathogen contamination in the animal production system. In addition, inconsistent results obtained with interventions of dietary additives or formulation modifications (grain versus forage; inclusion of distiller's grains) on pathogen prevalence in animals have been attributed to a range of factors including target organism, grain type, level of inclusion, the animal's health or stress level, and ability to survive the gastric acidic conditions. Recent attempts to microencapsulate organic acids or bacteriophage within feed have met with only marginal improvements in reducing pathogen carriage in animals but this approach may have greater potential with other antimicrobial additives (i.e., essential oils). Bacteriophage therapy, in general, can significantly reduce pathogen carriage in animals but based on its transient nature and the potential for development of phage-resistant subpopulations, this approach should be administered to animals just prior to slaughter and

  11. A new resting trap to sample fungus-infected mosquitoes, and the pathogenicity of Lecanicillium muscarium to culicid adults

    NARCIS (Netherlands)

    Luz, C.; Mnyone, L.L.; Sangusangu, R.; Lyimo, I.N.; Rocha, L.F.N.; Humber, R.A.; Russell, T.L.

    2010-01-01

    Some soil-dwelling entomopathogenic fungi that are widely used in pest control are also able to reduce the survival of adult mosquito vectors under laboratory conditions. However, there is still little information about the naturally occurring fungal pathogens affecting culicid mosquitoes. As such,

  12. Interaction between Food-borne Pathogens (Campylobacter jejuni, Salmonella Typhimurium and Listeria monocytogenes) and a Common Soil Flagellate (Cercomonas sp.)

    DEFF Research Database (Denmark)

    Bui, Thanh Xuan; Wolff, Anders; Madsen, Mogens

    2012-01-01

    Free-living protozoa may harbor, protect, and disperse bacteria, including those ingested and passed in viable form in feces. The flagellates are very important predators on bacteria in soil, but their role in the survival of food-borne pathogens associated with fruits and vegetables is not well...

  13. Brain transcriptomes of honey bees (Apis mellifera experimentally infected by two pathogens: Black queen cell virus and Nosema ceranae

    Directory of Open Access Journals (Sweden)

    Vincent Doublet

    2016-12-01

    Full Text Available Regulation of gene expression in the brain plays an important role in behavioral plasticity and decision making in response to external stimuli. However, both can be severely affected by environmental factors, such as parasites and pathogens. In honey bees, the emergence and re-emergence of pathogens and potential for pathogen co-infection and interaction have been suggested as major components that significantly impaired social behavior and survival. To understand how the honey bee is affected and responds to interacting pathogens, we co-infected workers with two prevalent pathogens of different nature, the positive single strand RNA virus Black queen cell virus (BQCV, and the Microsporidia Nosema ceranae, and explored gene expression changes in brains upon single infections and co-infections. Our data provide an important resource for research on honey bee diseases, and more generally on insect host-pathogen and pathogen-pathogen interactions. Raw and processed data are publicly available in the NCBI/GEO database: (http://www.ncbi.nlm.nih.gov/geo/ under accession number GSE81664.

  14. Comparative genome analysis of pathogenic and non-pathogenic Clavibacter strains reveals adaptations to their lifestyle

    OpenAIRE

    Załuga, Joanna; Stragier, Pieter; Baeyen, Steve; Haegeman, Annelies; Van Vaerenbergh, Johan; Maes, Martine; De Vos, Paul

    2014-01-01

    Background The genus Clavibacter harbors economically important plant pathogens infecting agricultural crops such as potato and tomato. Although the vast majority of Clavibacter strains are pathogenic, there is an increasing number of non-pathogenic isolates reported. Non-pathogenic Clavibacter strains isolated from tomato seeds are particularly problematic because they affect the current detection and identification tests for Clavibacter michiganensis subsp. michiganensis (Cmm), which is reg...

  15. Evasion Mechanisms Used by Pathogens to Escape the Lectin Complement Pathway

    DEFF Research Database (Denmark)

    Rosbjerg, Anne; Genster, Ninette; Pilely, Katrine

    2017-01-01

    the level of activity. The result is a pro-inflammatory response meant to combat foreign microbes. Microbial elimination is, however, not a straight forward procedure; pathogens have adapted to their environment by evolving a collection of evasion mechanisms that circumvent the human complement system....... Complement evasion strategies features different ways of exploiting human complement proteins and moreover features different pathogen-derived proteins that interfere with the normal processes. Accumulated, these mechanisms target all three complement activation pathways as well as the final common part...... of the cascade. This review will cover the currently known lectin pathway evasion mechanisms and give examples of pathogens that operate these to increase their chance of invasion, survival and dissemination....

  16. Potential role of bacteria packaging by protozoa in the persistence and transmission of pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Alix M Denoncourt

    2014-05-01

    Full Text Available Many pathogenic bacteria live in close association with protozoa. These unicellular eukaryotic microorganisms are ubiquitous in various environments. A number of protozoa such as amoebae and ciliates ingest pathogenic bacteria, package them usually in membrane structures, and then release them into the environment. Packaged bacteria are more resistant to various stresses and are more apt to survive than free bacteria. New evidence indicates that protozoa and not bacteria control the packaging process. It is possible that packaging is more common than suspected and may play a major role in the persistence and transmission of pathogenic bacteria. To confirm the role of packaging in the propagation of infections, it is vital that the molecular mechanisms governing the packaging of bacteria by protozoa be identified as well as elements related to the ecology of this process in order to determine whether packaging acts as a Trojan Horse.

  17. Abundance of sewage-pollution indicator and human pathogenic bacteria in a tropical estuarine complex

    Digital Repository Service at National Institute of Oceanography (India)

    Nagvenkar, G.S.; Ramaiah, N.

    contamination, allochthonous bacteria Introduction: Environmental surveys are necessary for understanding and documenting the occurrence and distribution of pollution indicator and human pathogenic bacteria. In order to quantify and understand... and Chandramohan 1993; Ruiz et al. 2000; Ramaiah and De 2003). Mortality and survival rates of fecal contamination indicator Escherichia coli in the marine regimes have also been studied (Thom et al. 1992; Darakas 2001). Findings from these studies affirm...

  18. Effective but costly, evolved mechanisms of defense against a virulent opportunistic pathogen in Drosophila melanogaster.

    OpenAIRE

    Yixin H Ye; Stephen F Chenoweth; Elizabeth A McGraw

    2009-01-01

    Drosophila harbor substantial genetic variation for antibacterial defense, and investment in immunity is thought to involve a costly trade-off with life history traits, including development, life span, and reproduction. To understand the way in which insects invest in fighting bacterial infection, we selected for survival following systemic infection with the opportunistic pathogen Pseudomonas aeruginosa in wild-caught Drosophila melanogaster over 10 generations. We then examined genome-wide...

  19. Impact of vector dispersal and host-plant fidelity on the dissemination of an emerging plant pathogen.

    Directory of Open Access Journals (Sweden)

    Jes Johannesen

    Full Text Available Dissemination of vector-transmitted pathogens depend on the survival and dispersal of the vector and the vector's ability to transmit the pathogen, while the host range of vector and pathogen determine the breath of transmission possibilities. In this study, we address how the interaction between dispersal and plant fidelities of a pathogen (stolbur phytoplasma tuf-a and its vector (Hyalesthes obsoletus: Cixiidae affect the emergence of the pathogen. Using genetic markers, we analysed the geographic origin and range expansion of both organisms in Western Europe and, specifically, whether the pathogen's dissemination in the northern range is caused by resident vectors widening their host-plant use from field bindweed to stinging nettle, and subsequent host specialisation. We found evidence for common origins of pathogen and vector south of the European Alps. Genetic patterns in vector populations show signals of secondary range expansion in Western Europe leading to dissemination of tuf-a pathogens, which might be newly acquired and of hybrid origin. Hence, the emergence of stolbur tuf-a in the northern range was explained by secondary immigration of vectors carrying stinging nettle-specialised tuf-a, not by widening the host-plant spectrum of resident vectors with pathogen transmission from field bindweed to stinging nettle nor by primary co-migration from the resident vector's historical area of origin. The introduction of tuf-a to stinging nettle in the northern range was therefore independent of vector's host-plant specialisation but the rapid pathogen dissemination depended on the vector's host shift, whereas the general dissemination elsewhere was linked to plant specialisation of the pathogen but not of the vector.

  20. Population genomics of fungal and oomycete pathogens

    Science.gov (United States)

    We are entering a new era in plant pathology where whole-genome sequences of many individuals of a pathogen species are becoming readily available. This era of pathogen population genomics will provide new opportunities and challenges, requiring new computational and analytical tools. Population gen...

  1. Immunity to plant pathogens and iron homeostasis.

    Science.gov (United States)

    Aznar, Aude; Chen, Nicolas W G; Thomine, Sebastien; Dellagi, Alia

    2015-11-01

    Iron is essential for metabolic processes in most living organisms. Pathogens and their hosts often compete for the acquisition of this nutrient. However, iron can catalyze the formation of deleterious reactive oxygen species. Hosts may use iron to increase local oxidative stress in defense responses against pathogens. Due to this duality, iron plays a complex role in plant-pathogen interactions. Plant defenses against pathogens and plant response to iron deficiency share several features, such as secretion of phenolic compounds, and use common hormone signaling pathways. Moreover, fine tuning of iron localization during infection involves genes coding iron transport and iron storage proteins, which have been shown to contribute to immunity. The influence of the plant iron status on the outcome of a given pathogen attack is strongly dependent on the nature of the pathogen infection strategy and on the host species. Microbial siderophores emerged as important factors as they have the ability to trigger plant defense responses. Depending on the plant species, siderophore perception can be mediated by their strong iron scavenging capacity or possibly via specific recognition as pathogen associated molecular patterns. This review highlights that iron has a key role in several plant-pathogen interactions by modulating immunity. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  2. Bacterial reproductive pathogens of cats and dogs.

    Science.gov (United States)

    Graham, Elizabeth M; Taylor, David J

    2012-05-01

    With the notable exception of Brucella canis, exogenous bacterial pathogens are uncommon causes of reproductive disease in cats and dogs. Most bacterial reproductive infections are endogenous, and predisposing factors for infection are important. This article reviews the etiology, pathogenesis, clinical presentation, diagnosis, treatment, and public health significance of bacterial reproductive pathogens in cats and dogs.

  3. Digital PCR for detection of citrus pathogens

    Science.gov (United States)

    Citrus trees are often infected with multiple pathogens of economic importance, especially those with insect or mite vectors. Real-time/quantitative PCR (qPCR) has been used for high-throughput detection and relative quantification of pathogens; however, target reference or standards are required. I...

  4. Occurrence of root parsley pathogens inhabiting seeds

    Directory of Open Access Journals (Sweden)

    Bogdan Nowicki

    2013-12-01

    Full Text Available The studies on root parsley pathogens inhabiting seeds were conducted during 1981-1988 and in 1993. Filter paper method with prefreezing and keeping under light was used. Each test sample comprised 500 seeds. Pathogenicity of collected fungal isolates was tested following two laboratory methods. 238 seed samples were studied. 18 fungal species were found but only 7 proved to be important pathogens of root parsley. The most common inhabitants of root parsley seeds were Alternaria spp. A.allernata occurred on 74,8% of seeds but only a few isolates showed to be slightly pathogenic while A.petroselini and A.radicina were higly pathogenic and inhabited 11,4 and 4,2% of seeds, respectively. The second group of important pathogens were species of Fusarium found on 3,9% of seeds. F.avenaceum dominated as it comprised 48% of Fusarium isolates, the next were as follow: F.culmorum - 20%, F.equiseti - 15%, F.solani - 8%, F.oxysporum - 7% and F.dimerum -2%. Some fungi like Botrytis cinerea, Septoria petroselini and Phoma spp. inhabited low number of seeds, respectively O,4; 0,5 and 0,8%, but they were highly pathogenic to root parsley. The fungi: Bipolaris sorokiniana, Drechslera biseptata, Stemphylium botryosum and Ulocludium consortiale showed slight pathogenicity. They were isolated from 3,8% of seeds.

  5. 77 FR 34783 - Highly Pathogenic Avian Influenza

    Science.gov (United States)

    2012-06-12

    ... [Docket No. APHIS-2006-0074] RIN 0579-AC36 Highly Pathogenic Avian Influenza AGENCY: Animal and Plant... regions where any subtype of highly pathogenic avian influenza (HPAI) is considered to exist. The interim... avian influenza (HPAI). On January 24, 2011, we published in the Federal Register (76 FR 4046-4056...

  6. THE OCCURRENCE, GROWTH AND CONTROL OF PATHOGENS ...

    African Journals Online (AJOL)

    Fermented foods have many advantageous attributes such as improved nutritional value and safety against bacterial pathogens. These foods are also important for weaning purposes and hence play a role in protecting infants against foodborne diseases. However, pathogens have been isolated from some fermented foods ...

  7. Tracing pathogens in the food chain

    NARCIS (Netherlands)

    Brul, S.; Fratamico, P.M.; McMeekin, T.A.

    2010-01-01

    Successful methods for the detection and investigation of outbreaks of foodborne disease are essential for ensuring consumer safety. Increased understanding of the transmission of pathogens in food chains will also assist efforts to safeguard public health. Tracing pathogens in the food chain

  8. Arthropods vector grapevine trunk disease pathogens.

    Science.gov (United States)

    Moyo, P; Allsopp, E; Roets, F; Mostert, L; Halleen, F

    2014-10-01

    Arthropod-mediated dispersal of pathogens is known in many cropping systems but has never been demonstrated for grapevine trunk disease pathogens. Arthropods from vineyards were screened for the presence of pathogens associated with Petri disease and esca using cultural and molecular techniques. The ability of the most abundant pathogen-carrying species to inoculate healthy grapevine vascular tissues was also determined. Millipedes and ants were allowed to associate with a DsRed- Express-transformed Phaeomoniella chlamydospora, after which they were exposed to freshly pruned healthy grapevines under controlled conditions and wounds were monitored for subsequent infection. In addition, the possibility of millipede excreta, commonly found on pruning wounds in the field, to act as inoculum source was determined. A diverse arthropod fauna was associated with declining grapevines and many of these carried trunk disease pathogens. However, spiders, the ant Crematogaster peringueyi, and the millipede Ommattoiulus moreleti were the most abundant pathogen carriers. The ant and millipede species fed on pruning wound sap and effectively transmitted trunk disease pathogens. Millipede excreta contained viable spores of Phaeomoniella chlamydospora and may serve as an inoculum source. Numerous arthropods, including beneficial predators, are potential vectors of grapevine trunk disease pathogens. Our results highlight the need for an integrated approach, including targeted management of ants and millipedes at the time of pruning, to limit the spread of grapevine trunk diseases.

  9. Pathogens' toolbox to manipulate human complement.

    Science.gov (United States)

    Fernández, Francisco J; Gómez, Sara; Vega, M Cristina

    2017-12-14

    The surveillance and pathogen fighting functions of the complement system have evolved to protect mammals from life-threatening infections. In turn, pathogens have developed complex molecular mechanisms to subvert, divert and evade the effector functions of the complement. The study of complement immunoevasion by pathogens sheds light on their infection drivers, knowledge that is essential to implement therapies. At the same time, complement evasion also acts as a discovery ground that reveals important aspects of how complement works under physiological conditions. In recent years, complex interrelationships between infection insults and the onset of autoimmune and complement dysregulation diseases have led to propose that encounters with pathogens can act as triggering factors for disease. The correct management of these diseases involves the recognition of their triggering factors and the development and administration of complement-associated molecular therapies. Even more recently, unsuspected proteins from pathogens have been shown to possess moonlighting functions as virulence factors, raising the possibility that behind the first line of virulence factors there be many more pathogen proteins playing secondary, helping and supporting roles for the pathogen to successfully establish infections. In an era where antibiotics have a progressively reduced effect on the management and control of infectious diseases worldwide, knowledge on the mechanisms of pathogenic invasion and evasion look more necessary and pressing than ever. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Pathogenic features of heterotrophic plate count bacteria from drinking-water boreholes.

    Science.gov (United States)

    Horn, Suranie; Pieters, Rialet; Bezuidenhout, Carlos

    2016-12-01

    Evidence suggests that heterotrophic plate count (HPC) bacteria may be hazardous to humans with weakened health. We investigated the pathogenic potential of HPC bacteria from untreated borehole water, consumed by humans, for: their haemolytic properties, the production of extracellular enzymes such as DNase, proteinase, lipase, lecithinase, hyaluronidase and chondroitinase, the effect simulated gastric fluid has on their survival, as well as the bacteria's antibiotic-susceptible profile. HuTu-80 cells acted as model for the human intestine and were exposed to the HPC isolates to determine their effects on the viability of the cells. Several HPC isolates were α- or β-haemolytic, produced two or more extracellular enzymes, survived the SGF treatment, and showed resistance against selected antibiotics. The isolates were also harmful to the human intestinal cells to varying degrees. A novel pathogen score was calculated for each isolate. Bacillus cereus had the highest pathogen index: the pathogenicity of the other bacteria declined as follows: Aeromonas taiwanensis > Aeromonas hydrophila > Bacillus thuringiensis > Alcaligenes faecalis > Pseudomonas sp. > Bacillus pumilus > Brevibacillus sp. > Bacillus subtilis > Bacillus sp. These results demonstrated that the prevailing standards for HPCs in drinking water may expose humans with compromised immune systems to undue risk.

  11. Pathogenic Acinetobacter: from the Cell Surface to Infinity and Beyond

    Science.gov (United States)

    Weber, Brent S.; Harding, Christian M.

    2015-01-01

    The genus Acinetobacter encompasses multiple nosocomial opportunistic pathogens that are of increasing worldwide relevance because of their ability to survive exposure to various antimicrobial and sterilization agents. Among these, Acinetobacter baumannii, Acinetobacter nosocomialis, and Acinetobacter pittii are the most frequently isolated in hospitals around the world. Despite the growing incidence of multidrug-resistant Acinetobacter spp., little is known about the factors that contribute to pathogenesis. New strategies for treating and managing infections caused by multidrug-resistant Acinetobacter strains are urgently needed, and this requires a detailed understanding of the pathobiology of these organisms. In recent years, some virulence factors important for Acinetobacter colonization have started to emerge. In this review, we focus on several recently described virulence factors that act at the bacterial surface level, such as the capsule, O-linked protein glycosylation, and adhesins. Furthermore, we describe the current knowledge regarding the type II and type VI secretion systems present in these strains. PMID:26712938

  12. Distinct lipid a moieties contribute to pathogen-induced site-specific vascular inflammation.

    Directory of Open Access Journals (Sweden)

    Connie Slocum

    2014-07-01

    Full Text Available Several successful pathogens have evolved mechanisms to evade host defense, resulting in the establishment of persistent and chronic infections. One such pathogen, Porphyromonas gingivalis, induces chronic low-grade inflammation associated with local inflammatory bone loss and systemic inflammation manifested as atherosclerosis. P. gingivalis expresses an atypical lipopolysaccharide (LPS structure containing heterogeneous lipid A species, that exhibit Toll-like receptor-4 (TLR4 agonist or antagonist activity, or are non-activating at TLR4. In this study, we utilized a series of P. gingivalis lipid A mutants to demonstrate that antagonistic lipid A structures enable the pathogen to evade TLR4-mediated bactericidal activity in macrophages resulting in systemic inflammation. Production of antagonistic lipid A was associated with the induction of low levels of TLR4-dependent proinflammatory mediators, failed activation of the inflammasome and increased bacterial survival in macrophages. Oral infection of ApoE(-/- mice with the P. gingivalis strain expressing antagonistic lipid A resulted in vascular inflammation, macrophage accumulation and atherosclerosis progression. In contrast, a P. gingivalis strain producing exclusively agonistic lipid A augmented levels of proinflammatory mediators and activated the inflammasome in a caspase-11-dependent manner, resulting in host cell lysis and decreased bacterial survival. ApoE(-/- mice infected with this strain exhibited diminished vascular inflammation, macrophage accumulation, and atherosclerosis progression. Notably, the ability of P. gingivalis to induce local inflammatory bone loss was independent of lipid A expression, indicative of distinct mechanisms for induction of local versus systemic inflammation by this pathogen. Collectively, our results point to a pivotal role for activation of the non-canonical inflammasome in P. gingivalis infection and demonstrate that P. gingivalis evades immune

  13. Type IV pili in Francisella – A virulence trait in an intracellular pathogen

    Directory of Open Access Journals (Sweden)

    Emelie eNäslund Salomonsson

    2011-02-01

    Full Text Available Francisella tularensis is a highly virulent intracellular human pathogen that is capable of rapid proliferation in the infected host. Mutants affected in intracellular survival and growth are highly attenuated which highlights the importance of the intracellular phase of the infection. Genomic analysis has revealed that Francisella encodes all genes required for expression of functional type IV pili (Tfp, and in this focused review we summarise recent findings regarding this system in the pathogenesis of tularemia. Tfp are dynamic adhesive structures that have been identified as major virulence determinants in several human pathogens, but it is not obvious what role these structures could have in an intracellular pathogen like Francisella. In the human pathogenic strains, genes required for secretion and assembly of Tfp and one pilin, PilA, have shown to be required for full virulence. Importantly, specific genetic differences have been identified between the different Francisella subspecies where in the most pathogenic type A variants all genes are intact while several Tfp genes are pseudogenes in the less pathogenic type B strains. This suggests that there has been a selection for expression of Tfp with different properties in the different subspecies. There is also a possibility that the genetic differences reflect adaption to different environmental niches of the subspecies and plays a role in transmission of tularemia. This is also in line with recent findings where Tfp pilins are found to be glycosylated which could reflect a role for Tfp in the environment to promote survival and transmission. We are still far from understanding the role of Tfp in virulence and transmission of tularemia, but with the genomic information and genetic tools available we are in a good position to address these issues in the future.

  14. Shigella IpaH Family Effectors as a Versatile Model for Studying Pathogenic Bacteria.

    Science.gov (United States)

    Ashida, Hiroshi; Sasakawa, Chihiro

    2015-01-01

    Shigella spp. are highly adapted human pathogens that cause bacillary dysentery (shigellosis). Via the type III secretion system (T3SS), Shigella deliver a subset of virulence proteins (effectors) that are responsible for pathogenesis, with functions including pyroptosis, invasion of the epithelial cells, intracellular survival, and evasion of host immune responses. Intriguingly, T3SS effector activity and strategies are not unique to Shigella, but are shared by many other bacterial pathogens, including Salmonella, Yersinia, and enteropathogenic Escherichia coli (EPEC). Therefore, studying Shigella T3SS effectors will not only improve our understanding of bacterial infection systems, but also provide a molecular basis for developing live bacterial vaccines and antibacterial drugs. One of Shigella T3SS effectors, IpaH family proteins, which have E3 ubiquitin ligase activity and are widely conserved among other bacterial pathogens, are very relevant because they promote bacterial survival by triggering cell death and modulating the host immune responses. Here, we describe selected examples of Shigella pathogenesis, with particular emphasis on the roles of IpaH family effectors, which shed new light on bacterial survival strategies and provide clues about how to overcome bacterial infections.

  15. Shigella IpaH family effectors as a versatile model for studying pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Hiroshi eAshida

    2016-01-01

    Full Text Available Shigella spp. are highly adapted human pathogens that cause bacillary dysentery (shigellosis. Via the type III secretion system (T3SS, Shigella deliver a subset of virulence proteins (effectors that are responsible for pathogenesis, with functions including pyroptosis, invasion of the epithelial cells, intracellular survival, and evasion of host immune responses. Intriguingly, T3SS effector activity and strategies are not unique to Shigella, but are shared by many other bacterial pathogens, including Salmonella, Yersinia, and enteropathogenic Escherichia coli (EPEC. Therefore, studying Shigella T3SS effectors will not only improve our understanding of bacterial infection systems, but also provide a molecular basis for developing live bacterial vaccines and antibacterial drugs. One of Shigella T3SS effectors, IpaH family proteins, which have E3 ubiquitin ligase activity and are widely conserved among other bacterial pathogens, are very relevant because they promote bacterial survival by triggering cell death and modulating the host immune responses. Here, we describe selected examples of Shigella pathogenesis, with particular emphasis on the roles of IpaH family effectors, which shed new light on bacterial survival strategies and provide clues about how to overcome bacterial infections.

  16. A Genetic Screen Reveals that Synthesis of 1,4-Dihydroxy-2-Naphthoate (DHNA), but Not Full-Length Menaquinone, Is Required for Listeria monocytogenes Cytosolic Survival.

    Science.gov (United States)

    Chen, Grischa Y; McDougal, Courtney E; D'Antonio, Marc A; Portman, Jonathan L; Sauer, John-Demian

    2017-03-21

    Through unknown mechanisms, the host cytosol restricts bacterial colonization; therefore, only professional cytosolic pathogens are adapted to colonize this host environment. Listeria monocytogenes is a Gram-positive intracellular pathogen that is highly adapted to colonize the cytosol of both phagocytic and nonphagocytic cells. To identify L. monocytogenes determinants of cytosolic survival, we designed and executed a novel screen to isolate L. monocytogenes mutants with cytosolic survival defects. Multiple mutants identified in the screen were defective for synthesis of menaquinone (MK), an essential molecule in the electron transport chain. Analysis of an extensive set of MK biosynthesis and respiratory chain mutants revealed that cellular respiration was not required for cytosolic survival of L. monocytogenes but that, instead, synthesis of 1,4-dihydroxy-2-naphthoate (DHNA), an MK biosynthesis intermediate, was essential. Recent discoveries showed that modulation of the central metabolism of both host and pathogen can influence the outcome of host-pathogen interactions. Our results identify a potentially novel function of the MK biosynthetic intermediate DHNA and specifically highlight how L. monocytogenes metabolic adaptations promote cytosolic survival and evasion of host immunity. IMPORTANCE Cytosolic bacterial pathogens, such as Listeria monocytogenes and Francisella tularensis , are exquisitely evolved to colonize the host cytosol in a variety of cell types. Establishing an intracellular niche shields these pathogens from effectors of humoral immunity, grants access to host nutrients, and is essential for pathogenesis. Through yet-to-be-defined mechanisms, the host cytosol restricts replication of non-cytosol-adapted bacteria, likely through a combination of cell autonomous defenses (CADs) and nutritional immunity. Utilizing a novel genetic screen, we identified determinants of L. monocytogenes cytosolic survival and virulence and identified a role

  17. Quantitative survival of Leptospira interrogans in soil and water microcosms.

    Science.gov (United States)

    Casanovas-Massana, Arnau; Pedra, Gabriel Ghizzi; Wunder, Elsio A; Diggle, Peter J; Begon, Mike; Ko, Albert I

    2018-04-27

    Leptospira interrogans is the etiological agent of leptospirosis, a globally distributed zoonotic disease. Human infection usually occurs through skin exposure with water and soil contaminated with the urine of chronically infected animals. In this study, we aimed to quantitatively characterize the survival of Leptospira interrogans serovar Copenhageni in environmental matrices. We constructed laboratory microcosms to simulate natural conditions and determined the persistence of DNA markers in soil, mud, spring water and sewage using a qPCR and a PMA-qPCR assay. We found that L. interrogans does not survive at high concentrations in the tested matrices. No net growth was detected in any of the experimental conditions and in all cases the concentration of the DNA markers targeted decreased from the beginning of the experiment following an exponential decay with a decreasing decay rate over time. After 12 and 21 days of incubation the spiked concentration of 10 6 L. interrogans cells/mL or g decreased to approximately 100 cells/mL or g in soil and spring water microcosms, respectively. Furthermore, culturable L. interrogans persisted at concentrations under the limit of detection by PMA-qPCR or qPCR for at least 16 days in soil and 28 days in spring water. Altogether our findings suggest that the environment is not a multiplication reservoir, but a temporary carrier of the L. interrogans Copenhageni, although the observed prolonged persistence at low concentrations may still enable the transmission of the disease. IMPORTANCE Leptospirosis is a zoonotic disease caused by spirochetes of the genus Leptospira that primarily affects impoverished populations worldwide. Although leptospirosis is transmitted by contact with water and soil, little is known about the ability of the pathogen to survive in the environment. In this study, we quantitatively characterized the survival of L. interrogans in environmental microcosms and found that although it cannot multiply in water

  18. The evolution of pathogenic trypanosomes

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    Jamie R. Stevens

    Full Text Available In the absence of a fossil record, the evolution of protozoa has until recently largely remained a matter for speculation. However, advances in molecular methods and phylogenetic analysis are now allowing interpretation of the "history written in the genes". This review focuses on recent progress in reconstruction of trypanosome phylogeny based on molecular data from ribosomal RNA, the miniexon and protein-coding genes. Sufficient data have now been gathered to demonstrate unequivocally that trypanosomes are monophyletic; the phylogenetic trees derived can serve as a framework to reinterpret the biology, taxonomy and present day distribution of trypanosome species, providing insights into the coevolution of trypanosomes with their vertebrate hosts and vectors. Different methods of dating the divergence of trypanosome lineages give rise to radically different evolutionary scenarios and these are reviewed. In particular, the use of one such biogeographically based approach provides new insights into the coevolution of the pathogens, Trypanosoma brucei and Trypanosoma cruzi, with their human hosts and the history of the diseases with which they are associated.

  19. Quorum Sensing of Periodontal Pathogens

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    Darije Plančak

    2015-01-01

    Full Text Available The term ‘quorum sensing’ describes intercellular bacterial communication which regulates bacterial gene expression according to population cell density. Bacteria produce and secrete small molecules, named autoinducers, into the intercellular space. The concentration of these molecules increases as a function of population cell density. Once the concentration of the stimulatory threshold is reached, alteration in gene expression occurs. Gram-positive and Gram-negative bacteria possess different types of quorum sensing systems. Canonical LuxI/R-type/acyl homoserine lactone mediated quorum sensing system is the best studied quorum sensing circuit and is described in Gram-negative bacteria which employ it for inter-species communication mostly. Grampositive bacteria possess a peptide-mediated quorum sensing system. Bacteria can communicate within their own species (intra-species but also between species (inter-species, for which they employ an autoinducer-2 quorum sensing system which is called the universal language of the bacteria. Periodontal pathogenic bacteria possess AI-2 quorum sensing systems. It is known that they use it for regulation of biofilm formation, iron uptake, stress response and virulence factor expression. A better understanding of bacterial communication mechanisms will allow the targeting of quorum sensing with quorum sensing inhibitors to prevent and control disease.

  20. Algae as reservoirs for coral pathogens.

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    Michael J Sweet

    Full Text Available Benthic algae are associated with coral death in the form of stress and disease. It's been proposed that they release exudates, which facilitate invasion of potentially pathogenic microbes at the coral-algal interface, resulting in coral disease. However, the original source of these pathogens remains unknown. This study examined the ability of benthic algae to act as reservoirs of coral pathogens by characterizing surface associated microbes associated with major Caribbean and Indo-Pacific algal species/types and by comparing them to potential pathogens of two dominant coral diseases: White Syndrome (WS in the Indo-Pacific and Yellow Band Disease (YBD in the Caribbean. Coral and algal sampling was conducted simultaneously at the same sites to avoid spatial effects. Potential pathogens were defined as those absent or rare in healthy corals, increasing in abundance in healthy tissues adjacent to a disease lesion, and dominant in disease lesions. Potentially pathogenic bacteria were detected in both WS and YBD and were also present within the majority of algal species/types (54 and 100% for WS and YBD respectively. Pathogenic ciliates were associated only with WS and not YBD lesions and these were also present in 36% of the Indo-Pacific algal species. Although potential pathogens were associated with many algal species, their presence was inconsistent among replicate algal samples and detection rates were relatively low, suggestive of low density and occurrence. At the community level, coral-associated microbes irrespective of the health of their host differed from algal-associated microbes, supporting that algae and corals have distinctive microbial communities associated with their tissue. We conclude that benthic algae are common reservoirs for a variety of different potential coral pathogens. However, algal-associated microbes alone are unlikely to cause coral death. Initial damage or stress to the coral via other competitive mechanisms is

  1. Pathogen-induced Caenorhabditis elegans developmental plasticity has a hormetic effect on the resistance to biotic and abiotic stresses

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    Leroy Magali

    2012-09-01

    Full Text Available Abstract Background Phenotypic plasticity, i.e. the capacity to change the phenotype in response to changes in the environment without alteration of the genotype, is important for coping with unstable environments. In spite of the ample evidence that microorganisms are a major environmental component playing a significant role in eukaryotic organisms health and disease, there is not much information about the effect of microorganism-induced developmental phenotypic plasticity on adult animals’ stress resistance and longevity. Results We examined the consequences of development of Caenorhabditis elegans larvae fed with different bacterial strains on stress resistance and lifespan of adult nematodes. Bacterial strains used in this study were either pathogenic or innocuous to nematodes. Exposure to the pathogen during development did not affect larval survival. However, the development of nematodes on the pathogenic bacterial strains increased lifespan of adult nematodes exposed to the same or a different pathogen. A longer nematode lifespan, developed on pathogens and exposed to pathogens as adults, did not result from an enhanced capacity to kill bacteria, but is likely due to an increased tolerance to the damage inflicted by the pathogenic bacteria. We observed that adult nematodes developed on a pathogen induce higher level of expression of the hsp-16.2 gene and have higher resistance to heat shock than nematodes developed on an innocuous strain. Therefore, the increased resistance to pathogens could be, at least partially, due to the early induction of the heat shock response in nematodes developed on pathogens. The lifespan increase is controlled by the DBL-1 transforming growth factor beta-like, DAF-2/DAF-16 insulin-like, and p38 MAP kinase pathways. Therefore, the observed modulation of adult nematode lifespans by developmental exposure to a pathogen is likely a genetically controlled response. Conclusions Our study shows that development

  2. Diverse structural approaches to haem appropriation by pathogenic bacteria.

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    Hare, Stephen A

    2017-04-01

    The critical need for iron presents a challenge for pathogenic bacteria that must survive in an environment bereft of accessible iron due to a natural low bioavailability and their host's nutritional immunity. Appropriating haem, either direct from host haemoproteins or by secreting haem-scavenging haemophores, is one way pathogenic bacteria can overcome this challenge. After capturing their target, haem appropriation systems must remove haem from a high-affinity binding site (on the host haemoprotein or bacterial haemophore) and transfer it to a binding site of lower affinity on a bacterial receptor. Structural information is now available to show how, using a combination of induced structural changes and steric clashes, bacteria are able to extract haem from haemophores, haemopexin and haemoglobin. This review focuses on structural descriptions of these bacterial haem acquisition systems, summarising how they bind haem and their target haemoproteins with particularly emphasis on the mechanism of haem extraction. Copyright © 2017 The Author. Published by Elsevier B.V. All rights reserved.

  3. Plasticity in early immune evasion strategies of a bacterial pathogen.

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    Bernard, Quentin; Smith, Alexis A; Yang, Xiuli; Koci, Juraj; Foor, Shelby D; Cramer, Sarah D; Zhuang, Xuran; Dwyer, Jennifer E; Lin, Yi-Pin; Mongodin, Emmanuel F; Marques, Adriana; Leong, John M; Anguita, Juan; Pal, Utpal

    2018-04-17

    Borrelia burgdorferi is one of the few extracellular pathogens capable of establishing persistent infection in mammals. The mechanisms that sustain long-term survival of this bacterium are largely unknown. Here we report a unique innate immune evasion strategy of B. burgdorferi , orchestrated by a surface protein annotated as BBA57, through its modulation of multiple spirochete virulent determinants. BBA57 function is critical for early infection but largely redundant for later stages of spirochetal persistence, either in mammals or in ticks. The protein influences host IFN responses as well as suppresses multiple host microbicidal activities involving serum complement, neutrophils, and antimicrobial peptides. We also discovered a remarkable plasticity in BBA57-mediated spirochete immune evasion strategy because its loss, although resulting in near clearance of pathogens at the inoculum site, triggers nonheritable adaptive changes that exclude detectable nucleotide alterations in the genome but incorporate transcriptional reprograming events. Understanding the malleability in spirochetal immune evasion mechanisms that ensures their host persistence is critical for the development of novel therapeutic and preventive approaches to combat long-term infections like Lyme borreliosis.

  4. Pathogenic Leptospira: Advances in understanding the molecular pathogenesis and virulence

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    Ghazaei, Ciamak

    2018-01-01

    Leptospirosis is a common zoonotic disease has emerged as a major public health problem, with developing countries bearing disproportionate burdens. Although the diverse range of clinical manifestations of the leptospirosis in humans is widely documented, the mechanisms through which the pathogen causes disease remain undetermined. In addition, leptospirosis is a much-neglected life-threatening disease although it is one of the most important zoonoses occurring in a diverse range of epidemiological distribution. Recent advances in molecular profiling of pathogenic species of the genus Leptospira have improved our understanding of the evolutionary factors that determine virulence and mechanisms that the bacteria employ to survive. However, a major impediment to the formulation of intervention strategies has been the limited understanding of the disease determinants. Consequently, the association of the biological mechanisms to the pathogenesis of Leptospira, as well as the functions of numerous essential virulence factors still remain implicit. This review examines recent advances in genetic screening technologies, the underlying microbiological processes, the virulence factors and associated molecular mechanisms driving pathogenesis of Leptospira species. PMID:29445617

  5. Helicobacter pylori - a seasoned pathogen by any other name

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    Ahmed Niyaz

    2009-12-01

    Full Text Available Abstract Helicobacter pylori is a well known inhabitant of human stomach which is linked to peptic ulcer disease and gastric adenocarcinoma. It was recently shown in several studies that H. pylori can be harnessed as a surrogate marker of human migration and that its population structure and stratification patterns exactly juxtapose to those of Homo sapiens. This is enough a testimony to convey that H. pylori may have coevolved with their host. Several protective effects of H. pylori colonization have been considered as evidence of a presumed symbiotic relationship. Contrary to this assumption is the presence of a strong virulence apparatus within H. pylori; why a co-evolved parasite would try inflicting its host with serious infection and even causing cancer? The answer is perhaps embedded in the evolutionary history of both the bacterium and the host. We discuss a hypothetical scenario wherein H. pylori may have acquired virulence genes from donors within its environment that varied with change in human history and ecology. The H. pylori genomes sequenced to date portray fairly high abundance of such laterally acquired genes which have no assigned functions but could be linked to inflammatory responses or other pathogenic attributes. Therefore, the powerful virulence properties and survival strategies of Helicobacter make it a seasoned pathogen; thus the efforts to portray it as a commensal or a (harmless 'bacterial parasite' need rethinking.

  6. Alterations in the health of hibernating bats under pathogen pressure.

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    Bandouchova, Hana; Bartonička, Tomáš; Berkova, Hana; Brichta, Jiri; Kokurewicz, Tomasz; Kovacova, Veronika; Linhart, Petr; Piacek, Vladimir; Pikula, Jiri; Zahradníková, Alexandra; Zukal, Jan

    2018-04-17

    In underground hibernacula temperate northern hemisphere bats are exposed to Pseudogymnoascus destructans, the fungal agent of white-nose syndrome. While pathological and epidemiological data suggest that Palearctic bats tolerate this infection, we lack knowledge about bat health under pathogen pressure. Here we report blood profiles, along with body mass index (BMI), infection intensity and hibernation temperature, in greater mouse-eared bats (Myotis myotis). We sampled three European hibernacula that differ in geomorphology and microclimatic conditions. Skin lesion counts differed between contralateral wings of a bat, suggesting variable exposure to the fungus. Analysis of blood parameters suggests a threshold of ca. 300 skin lesions on both wings, combined with poor hibernation conditions, may distinguish healthy bats from those with homeostatic disruption. Physiological effects manifested as mild metabolic acidosis, decreased glucose and peripheral blood eosinophilia which were strongly locality-dependent. Hibernating bats displaying blood homeostasis disruption had 2 °C lower body surface temperatures. A shallow BMI loss slope with increasing pathogen load suggested a high degree of infection tolerance. European greater mouse-eared bats generally survive P. destructans invasion, despite some health deterioration at higher infection intensities (dependant on hibernation conditions). Conservation measures should minimise additional stressors to conserve constrained body reserves of bats during hibernation.

  7. Serosurvey for selected pathogens in Iberian roe deer

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    Oleaga Álvaro

    2010-11-01

    Full Text Available Abstract Background The roe deer is the most abundant and widespread wild Eurasian cervid. Its populations are expanding and increasingly in contact with livestock. This may affect the distribution of infectious diseases shared with other wild and domestic ungulates. Methods We investigated the antibody seroprevalence against Pestivirus, Herpesvirus, Bluetongue (BT virus, M. avium paratuberculosis (MAP, and Brucella sp. in 519 roe deer from different regions in Spain, south-western Europe. Results No antibodies were detected against BT and Brucella sp. However, antibodies were detected against Pestivirus (1.5%, Herpesvirus (0.2% and MAP (9.2%. MAP antibodies were detected in seven of the eight populations (range 5-16.4%. Conclusions The detection of MAP antibodies in samples from most roe deer populations suggests that contact with MAP is widespread in this wildlife species. The highest prevalence was detected in sites with abundant dairy cattle and frequent use of liquid manure on pastures. Considering the results obtained regarding exposure to different pathogens, we suggest that antibody prevalences in this non-gregarious browser are largely determined by environmental factors, potentially modulating vector populations or pathogen survival in the environment.

  8. Rhodococcus equi: the many facets of a pathogenic actinomycete.

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    Vázquez-Boland, José A; Giguère, Steeve; Hapeshi, Alexia; MacArthur, Iain; Anastasi, Elisa; Valero-Rello, Ana

    2013-11-29

    Rhodococcus equi is a soil-dwelling pathogenic actinomycete that causes pulmonary and extrapulmonary pyogranulomatous infections in a variety of animal species and people. Young foals are particularly susceptible and develop a life-threatening pneumonic disease that is endemic at many horse-breeding farms worldwide. R. equi is a facultative intracellular parasite of macrophages that replicates within a modified phagocytic vacuole. Its pathogenicity depends on a virulence plasmid that promotes intracellular survival by preventing phagosome-lysosome fusion. Species-specific tropism of R. equi for horses, pigs and cattle appears to be determined by host-adapted virulence plasmid types. Molecular epidemiological studies of these plasmids suggest that human R. equi infection is zoonotic. Analysis of the recently determined R. equi genome sequence has identified additional virulence determinants on the bacterial chromosome. This review summarizes our current understanding of the clinical aspects, biology, pathogenesis and immunity of this fascinating microbe with plasmid-governed infectivity. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Biological activity of Penaeus monodon GILT in shrimp pathogen protection

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    Aekkaraj Nualla-ong

    2017-04-01

    Full Text Available Gamma-interferon-inducible lysosomal thiol reductase (GILT contains a CXXC active site motif that possesses thiol reductase activity by catalyzing the disulfide bond reduction of exogenous antigens. Mutating the active site of human GILT to change the cysteine residues to serine residues eliminates this property. Our previous study reported that Penaeus monodon GILT (PmGILT contained a CXXS active site motif. Therefore, we assessed the enzymatic activity of PmGILT and demonstrated that it displayed identical thiol reductase activity at an acidic pH. In addition, the biological activity of PmGILT against shrimp pathogens, including white spot syndrome virus (WSSV and Gram-negative bacteria, was investigated. The neutralization of WSSV with PmGILT indicated the inhibition of WSSV invasion into shrimp hemocyte cells. Moreover, the relative percentage survival of shrimp injected with PmGILT-treated virus solution was 75%. Finally, the antimicrobial activity of PmGILT was confirmed by the growth inhibition of Vibrio harveyi. These results establish the role of PmGILT in the inhibition of the virulence of two major shrimp pathogens.

  10. Cell Survival Signaling in Neuroblastoma

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    Megison, Michael L.; Gillory, Lauren A.; Beierle, Elizabeth A.

    2013-01-01

    Neuroblastoma is the most common extracranial solid tumor of childhood and is responsible for over 15% of pediatric cancer deaths. Neuroblastoma tumorigenesis and malignant transformation is driven by overexpression and dominance of cell survival pathways and a lack of normal cellular senescence or apoptosis. Therefore, manipulation of cell survival pathways may decrease the malignant potential of these tumors and provide avenues for the development of novel therapeutics. This review focuses on several facets of cell survival pathways including protein kinases (PI3K, AKT, ALK, and FAK), transcription factors (NF-κB, MYCN and p53), and growth factors (IGF, EGF, PDGF, and VEGF). Modulation of each of these factors decreases the growth or otherwise hinders the malignant potential of neuroblastoma, and many therapeutics targeting these pathways are already in the clinical trial phase of development. Continued research and discovery of effective modulators of these pathways will revolutionize the treatment of neuroblastoma. PMID:22934706

  11. Survival of Sami cancer patients

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    Leena Soininen

    2012-07-01

    Full Text Available Objectives. The incidence of cancer among the indigenous Sami people of Northern Finland is lower than among the Finnish general population. The survival of Sami cancer patients is not known, and therefore it is the object of this study. Study design. The cohort consisted of 2,091 Sami and 4,161 non-Sami who lived on 31 December 1978 in the two Sami municipalities of Inari and Utsjoki, which are located in Northern Finland and are 300–500 km away from the nearest central hospital. The survival experience of Sami and non-Sami cancer patients diagnosed in this cohort during 1979–2009 was compared with that of the Finnish patients outside the cohort. Methods. The Sami and non-Sami cancer patients were matched to other Finnish cancer patients for gender, age and year of diagnosis and for the site of cancer. An additional matching was done for the stage at diagnosis. Cancer-specific survival analyses were made using the Kaplan–Meier method and Cox regression modelling. Results. There were 204 Sami and 391 non-Sami cancer cases in the cohort, 20,181 matched controls without matching with stage, and 7,874 stage-matched controls. In the cancer-specific analysis without stage variable, the hazard ratio for Sami was 1.05 (95% confidence interval 0.85–1.30 and for non-Sami 1.02 (0.86–1.20, indicating no difference between the survival of those groups and other patients in Finland. Likewise, when the same was done by also matching the stage, there was no difference in cancer survival. Conclusion. Long distances to medical care or Sami ethnicity have no influence on the cancer patient survival in Northern Finland.

  12. Aircraft Survivability: Survivability in The Low Altitude Regime, Summer 2009

    Science.gov (United States)

    2009-01-01

    elevation, sun location, temperature, humidity, ozone level, visibility, cloud coverage, and wind speed and direction. Survivability in the Low Altitude...JASP Summer PMSG 14–16 July 2009 Key West, FL AUG 45th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit 2–5 August 2009 Denver, CO

  13. Efferocytosis of Pathogen-Infected Cells

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    Niloofar Karaji

    2017-12-01

    Full Text Available The prompt and efficient clearance of unwanted and abnormal cells by phagocytes is termed efferocytosis and is crucial for organism development, maintenance of tissue homeostasis, and regulation of the immune system. Dying cells are recognized by phagocytes through pathways initiated via “find me” signals, recognition via “eat me” signals and down-modulation of regulatory “don’t eat me” signals. Pathogen infection may trigger cell death that drives phagocytic clearance in an immunologically silent, or pro-inflammatory manner, depending on the mode of cell death. In many cases, efferocytosis is a mechanism for eliminating pathogens and pathogen-infected cells; however, some pathogens have subverted this process and use efferocytic mechanisms to avoid innate immune detection and assist phagocyte infection. In parallel, phagocytes can integrate signals received from infected dying cells to elicit the most appropriate effector response against the infecting pathogen. This review focuses on pathogen-induced cell death signals that drive infected cell recognition and uptake by phagocytes, and the outcomes for the infected target cell, the phagocyte, the pathogen and the host.

  14. Waterborne Pathogens: Detection Methods and Challenges

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    Flor Yazmín Ramírez-Castillo

    2015-05-01

    Full Text Available Waterborne pathogens and related diseases are a major public health concern worldwide, not only by the morbidity and mortality that they cause, but by the high cost that represents their prevention and treatment. These diseases are directly related to environmental deterioration and pollution. Despite the continued efforts to maintain water safety, waterborne outbreaks are still reported globally. Proper assessment of pathogens on water and water quality monitoring are key factors for decision-making regarding water distribution systems’ infrastructure, the choice of best water treatment and prevention waterborne outbreaks. Powerful, sensitive and reproducible diagnostic tools are developed to monitor pathogen contamination in water and be able to detect not only cultivable pathogens but also to detect the occurrence of viable but non-culturable microorganisms as well as the presence of pathogens on biofilms. Quantitative microbial risk assessment (QMRA is a helpful tool to evaluate the scenarios for pathogen contamination that involve surveillance, detection methods, analysis and decision-making. This review aims to present a research outlook on waterborne outbreaks that have occurred in recent years. This review also focuses in the main molecular techniques for detection of waterborne pathogens and the use of QMRA approach to protect public health.

  15. Comparative pathogenicity of Vibrio spp., Photobacterium damselae ssp. damselae and five isolates of Aeromonas salmonicida ssp. achromogenes in juvenile Atlantic halibut (Hippoglossus hippoglossus).

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    Bowden, T J; Bricknell, I R; Preziosi, B M

    2018-01-01

    Juvenile Atlantic halibut (~100 mg, Hippoglossus hippoglossus) were exposed to Vibrio proteolyticus, a Vibrio spp. isolate, Photobacterium damselae ssp. damselae and five different isolates of Aeromonas salmonicida ssp. achromogenes via an hour-long bath immersion to ascertain their variation in pathogenicity to this fish species. Results were analysed using Kaplan-Meier survival analysis. Analysis of the data from challenges using A. salmonicida ssp. achromogenes revealed three survival values of zero and a spread of values from 0 to 28.43. Challenges using a Vibrio spp isolate, V. proteolyticus and P. damselae resulted in Kaplan-Meier survival estimates of 31.21, 50.41 and 57.21, respectively. As all bacterial species tested could induce juvenile halibut mortalities, they must all be considered as potential pathogens. However, the degree of pathogenicity of A. salmonicida is isolate dependent. © 2017 John Wiley & Sons Ltd.

  16. Poly-β-hydroxybutyrate (PHB) accumulating Bacillus spp. improve the survival, growth and robustness of Penaeus monodon (Fabricius, 1798) postlarvae.

    Science.gov (United States)

    Laranja, Joseph Leopoldo Q; Ludevese-Pascual, Gladys L; Amar, Edgar C; Sorgeloos, Patrick; Bossier, Peter; De Schryver, Peter

    2014-10-10

    Low larval survival resulting from suboptimal culture conditions and luminous vibriosis poses a major problem for the larviculture of penaeid shrimp. In this study, a poly-β-hydroxybutyrate (PHB) accumulating mixed bacterial culture (mBC; 48.5% PHB on cell dry weight) and two PHB accumulating bacterial isolates, Bacillus sp. JL47 (54.7% PHB on cell dry weight) and Bacillus sp. JL1 (45.5% PHB on cell dry weight), were obtained from a Philippine shrimp culture pond and investigated for their capacity to improve growth, survival and robustness of Penaeus monodon postlarvae (PL). Shrimp PL1 and shrimp PL30 were provided with the PHB containing bacterial cultures in the feed for 30 days followed by, respectively, a challenge with pathogenic Vibrio campbellii and exposure to a lethal dose of ammonia. Prior to the pathogenic challenge or ammonia stress, growth and survival were higher for shrimp receiving the PHB accumulating bacteria as compared to shrimp receiving diets without bacterial additions. After exposure to the pathogenic challenge the shrimp fed PHB accumulating bacteria showed a higher survival as compared to non-treated shrimp, suggesting an increase in robustness for the shrimp. Similar effects were observed when shrimp PL30 were provided with the PHB accumulating bacterial cultures during a challenge with pathogenic V. campbellii through the water. The survival of shrimp exposed to lethal ammonia stress showed no significant difference between PHB accumulating bacteria-fed shrimp and non-PHB treated shrimp. The data illustrate that bacilli capable of accumulating PHB can provide beneficial effects to P. monodon post-larvae during culture in terms of growth performance, survival and resistance against pathogenic infection and ammonia stress. Further investigations are required to verify the PHB effect of the bacterial cultures on the shrimp. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Inorganic Polyphosphate Is Essential for Salmonella Typhimurium Virulence and Survival in Dictyostelium discoideum

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    Macarena A. Varas

    2018-01-01

    Full Text Available Inorganic polyphosphate (polyP deficiency in enteric bacterial pathogens reduces their ability to invade and establish systemic infections in different hosts. For instance, inactivation of the polyP kinase gene (ppk encoding the enzyme responsible for polyP biosynthesis reduces invasiveness and intracellular survival of Salmonella enterica serovar Typhimurium (S. Typhimurium in epithelial cells and macrophages in vitro. In addition, the virulence in vivo of a S. Typhimurium Δppk mutant is significantly reduced in a murine infection model. In spite of these observations, the role played by polyP during the Salmonella-host interaction is not well understood. The social amoeba Dictyostelium discoideum has proven to be a useful model for studying relevant aspects of the host-pathogen interaction. In fact, many intracellular pathogens can survive within D. discoideum cells using molecular mechanisms also required to survive within macrophages. Recently, we established that S. Typhimurium is able to survive intracellularly in D. discoideum and identified relevant genes linked to virulence that are crucial for this process. The aim of this study was to determine the effect of a polyP deficiency in S. Typhimurium during its interaction with D. discoideum. To do this, we evaluated the intracellular survival of wild-type and Δppk strains of S. Typhimurium in D. discoideum and the ability of these strains to delay the social development of the amoeba. In contrast to the wild-type strain, the Δppk mutant was unable to survive intracellularly in D. discoideum and enabled the social development of the amoeba. Both phenotypes were complemented using a plasmid carrying a copy of the ppk gene. Next, we simultaneously evaluated the proteomic response of both S. Typhimurium and D. discoideum during host-pathogen interaction via global proteomic profiling. The analysis of our results allowed the identification of novel molecular signatures that give insight into

  18. Solar irradiance limits the long-term survival of Listeria monocytogenes in seawater.

    Science.gov (United States)

    NicAogáin, K; Magill, D; O'Donoghue, B; Conneely, A; Bennett, C; O'Byrne, C P

    2018-03-01

    Seafood has often been implicated in outbreaks of food-borne illness caused by Listeria monocytogenes but the source of contamination is usually not known. In this study we investigated the possibility that this pathogen could survive in seawater for an extended time period. Freshly collected seawater samples were inoculated with 1 × 10 8  CFU per ml of L. monocytogenes EGD-e and survival was monitored by plate counting for up to 25 days. When incubated in the dark, either at ambient temperatures (4-14°C) or at 16°C, >10 4  CFU per ml survivors were present after 25 days. However, when the seawater cell suspensions were exposed to ambient light (solar irradiation) and temperatures, L. monocytogenes lost viability rapidly and no survivors could be detected after the 80 h time point. Both UV-A and visible light in the blue region of the spectrum (470 nm) were found to contribute to this effect. The stress inducible sigma factor σ B was found to play a role in survival of L. monocytogenes in seawater. Together these data demonstrate that solar irradiation is a critical determinant of L. monocytogenes survival in marine environments. The data further suggest the possibility of controlling this food-borne pathogen in food-processing environments using visible light. Listeria monocytogenes is a food-borne bacterial pathogen capable of causing the life-threatening infection, listeriosis. In seafood the route of contamination from the environment is often not well understood as this pathogen is not generally thought to survive well in seawater. Here we provide evidence that L. monocytogenes is capable of surviving for long periods of time in seawater when light is excluded. Sunlight is demonstrated to have a significant effect on the survival of this pathogen in seawater, and both visible (470 nm) and UV-A light are shown to contribute to this effect. © 2017 The Society for Applied Microbiology.

  19. Laser inactivation of pathogenic viruses in water

    Science.gov (United States)

    Grishkanich, Alexander; Zhevlakov, Alexander; Kascheev, Sergey; Sidorov, Igor; Ruzankina, Julia; Yakovlev, Alexey; Mak, Andrey

    2016-03-01

    Currently there is a situation that makes it difficult to provide the population with quality drinking water for the sanitary-hygienic requirements. One of the urgent problems is the need for water disinfection. Since the emergence of microorganisms that are pathogens transmitted through water such as typhoid, cholera, etc. requires constant cleansing of waters against pathogenic bacteria. In the water treatment process is destroyed up to 98% of germs, but among the remaining can be pathogenic viruses, the destruction of which requires special handling. As a result, the conducted research the following methods have been proposed for combating harmful microorganisms: sterilization of water by laser radiation and using a UV lamp.

  20. Role of mannitol metabolism in the pathogenicity of the necrotrophic fungus Alternaria brassicicola

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    Benoit eCalmes

    2013-05-01

    Full Text Available In this study, the physiological functions of fungal mannitol metabolism in the pathogenicity and protection against environmental stresses were investigated in the necrotrophic fungus Alternaria brassicicola. Mannitol metabolism was examined during infection of Brassica oleracea leaves by sequential HPLC quantification of the major soluble carbohydrates and expression analysis of genes encoding two proteins of mannitol metabolism, i.e. a mannitol dehydrogenase (AbMdh, and a mannitol-1-phosphate dehydrogenase (AbMpd. Knockout mutants deficient for AbMdh or AbMpd and a double mutant lacking both enzyme activities were constructed. Their capacity to cope with various oxidative and drought stresses and their pathogenic behaviour were evaluated. Metabolic and gene expression profiling indicated an increase in mannitol production during plant infection. Depending on the mutants, distinct pathogenic processes, such as leaf and silique colonization, sporulation, survival on seeds, were impaired by comparison to the wild-type. This pathogenic alteration could be partly explained by the differential susceptibilities of mutants to oxidative and drought stresses. These results highlight the importance of mannitol metabolism with respect to the ability of A. brassicicola to efficiently accomplish key steps of its pathogenic life cycle.

  1. Recovery Estimation of Dried Foodborne Pathogens Is Directly Related to Rehydration Kinetics

    Science.gov (United States)

    Lang, Emilie; Zoz, Fiona; Iaconelli, Cyril; Guyot, Stéphane; Alvarez-Martin, Pablo; Beney, Laurent; Perrier-Cornet, Jean-Marie; Gervais, Patrick

    2016-01-01

    Drying is a common process which is used to preserve food products and technological microorganisms, but which is deleterious for the cells. The aim of this study is to differentiate the effects of drying alone from the effects of the successive and necessary rehydration. Rehydration of dried bacteria is a critical step already studied in starter culture but not for different kinetics and not for pathogens. In the present study, the influence of rehydration kinetics was investigated for three foodborne pathogens involved in neonatal diseases caused by the consumption of rehydrated milk powder: Salmonella enterica subsp. enterica serovar Typhimurium, Salmonella enterica subsp. enterica serovar Senftenberg and Cronobacter sakazakii. Bacteria were dried in controlled relative humidity atmospheres and then rehydrated using different methods. Our results showed that the survival of the three pathogens was strongly related to rehydration kinetics. Consequently, rehydration is an important step to consider during food safety assessment or during studies of dried foodborne pathogens. Also, it has to be considered with more attention in consumers’ homes during the preparation of food, like powdered infant formula, to avoid pathogens recovery. PMID:27494169

  2. Effect of environmental parameters on pathogen and faecal indicator organism concentrations within an urban estuary

    Science.gov (United States)

    Henry, Rebekah; Schang, Christelle; Kolotelo, Peter; Coleman, Rhys; Rooney, Graham; Schmidt, Jonathan; Deletic, Ana; McCarthy, David T.

    2016-06-01

    Current World Health Organisation figures estimate that ∼2.5 million deaths per year result from recreational contact with contaminated water sources. Concerns about quantitative risk assessments of waterways using faecal indicator organisms (FIOs) as surrogates to infer pathogenic risk currently exist. In Melbourne, Australia, the Yarra River has come under public scrutiny due to perceived public health risks associated with aquatic recreation; a characteristic shared with urban estuaries worldwide. A 10-month study of the Yarra estuary investigated the processes that affect FIOs and pathogens within this system. A total of 74 samples were collected from three estuarine and two upstream, freshwater, locations under different climatic and hydrological conditions, and the levels of Escherichia coli, enterococci, Clostridium perfringens, fRNA coliphages, Campylobacter spp. Cryptosporidium oocysts, Giardia cysts, adenoviruses, and enteroviruses were monitored. Reference pathogenic bacteria, protozoa, and viruses were detected in 81%, 19%, and 8% of samples, respectively. Variations in FIO concentrations were found to be associated with changes in specific climatic and hydrological variables including: temperature, flow, humidity and rainfall. In contrast, pathogen levels remained unaffected by all variables investigated. Limitations of current national and international culture-based standard methods may have played a significant role in limiting the identification of correlative relationships The data demonstrate the differences between FIOs and microbial pathogens in terms of sources, sinks, and survival processes within an urban estuary and provide further evidence of the inadequacy of FIO inclusion in the development of worldwide regulatory water quality criteria and risk assessment models.

  3. Recovery Estimation of Dried Foodborne Pathogens Is Directly Related to Rehydration Kinetics.

    Directory of Open Access Journals (Sweden)

    Emilie Lang

    Full Text Available Drying is a common process which is used to preserve food products and technological microorganisms, but which is deleterious for the cells. The aim of this study is to differentiate the effects of drying alone from the effects of the successive and necessary rehydration. Rehydration of dried bacteria is a critical step already studied in starter culture but not for different kinetics and not for pathogens. In the present study, the influence of rehydration kinetics was investigated for three foodborne pathogens involved in neonatal diseases caused by the consumption of rehydrated milk powder: Salmonella enterica subsp. enterica serovar Typhimurium, Salmonella enterica subsp. enterica serovar Senftenberg and Cronobacter sakazakii. Bacteria were dried in controlled relative humidity atmospheres and then rehydrated using different methods. Our results showed that the survival of the three pathogens was strongly related to rehydration kinetics. Consequently, rehydration is an important step to consider during food safety assessment or during studies of dried foodborne pathogens. Also, it has to be considered with more attention in consumers' homes during the preparation of food, like powdered infant formula, to avoid pathogens recovery.

  4. Pathogen inactivation in liquid dairy manure during anaerobic and aerobic digestions

    Science.gov (United States)

    Biswas, S.; Pandey, P.; Castillo, A. R.; Vaddella, V. K.

    2014-12-01

    Controlling manure-borne pathogens such as E. coli O157:H7, Salmonella spp. and Listeria monocytogenes are crucial for protecting surface and ground water as well as mitigating risks to human health. In California dairy farms, flushing of dairy manure (mainly animal feces and urine) from freestall barns and subsequent liquid-solid manure separation is a common practice for handling animal waste. The liquid manure fraction is generally pumped into the settling ponds and it goes into aerobic and/or anaerobic lagoons for extended period of time. Considering the importance of controlling pathogens in animal waste, the objective of the study was to understand the effects of anaerobic and aerobic digestions on the survival of three human pathogens in animal waste. The pathogen inactivation was assessed at four temperatures (30, 35, 42, and 50 °C), and the relationships between temperature and pathogen decay were estimated. Results showed a steady decrease of E. coli levels in aerobic and anaerobic digestion processes over the time; however, the decay rates varied with pathogens. The effect of temperature on Salmonella spp. and Listeria monocytogenes survival was different than the E. coli survival. In thermophilic temperatures (42 and 50 °C), decay rate was considerable greater compared to the mesophilic temperatures (30 and 35°C). The E. coli log reductions at 50 °C were 2.1 in both aerobic and anaerobic digestions after 13 days of incubation. The Salmonella spp. log reductions at 50 °C were 5.5 in aerobic digestion, and 5.9 in anaerobic digestion. The Listeria monocytogenes log reductions at 50 °C were 5.0 in aerobic digestion, and 5.6 in anaerobic digestion. The log reduction of E. coli, Salmonella spp., and Listeria monocytogens at 30 °C in aerobic environment were 0.1, 4.7, and 5.6, respectively. In anaerobic environment, the corresponding reductions were 0.4, 4.3, and 5.6, respectively. We anticipate that the outcomes of the study will help improving the

  5. Construction of a Nocardia brasiliensis fluorescent plasmid to study Actinomycetoma pathogenicity.

    Science.gov (United States)

    Salinas-Carmona, Mario C; Rocha-Pizaña, María R

    2011-01-01

    Nocardia brasiliensis, is a bacteria that lives as saprophyte in soil and causes a disease called actinomycetoma in both human and animals. Nocardia brasiliensis is an intracellular, facultative bacterium that replicates and survives within host macrophages. The mechanisms involved in the evasion of the microbicidal actions of macrophages remain unclear. The filamentous growth of N. brasiliensis is resistant to unicellular preparations, leading to inaccurate quantification of bacterial numbers by means of colony forming units (CFU). As successful survival studies with green fluorescent protein (GFP)-expressing bacterial strains have been reported, we constructed a recombinant GFP-expressing strain of N. brasiliensis. The virulence of the modified strain is maintained because it induces mycetoma in BALB/c mice. This new strain can be used for bacterial survival assays using cytometry and to elucidate the pathogenicity mechanisms in Actinomycetoma infection. Copyright © 2010 Elsevier Inc. All rights reserved.

  6. Genetic aspects of piglet survival

    NARCIS (Netherlands)

    Knol, E.F.

    2001-01-01

    Piglet mortality is high. In the USA nearly 20% of the piglets do not survive between late gestation and weaning; 7% of the piglets die during farrowing and some 13% are lost during lactation. These statistics from the USA are no exception to the norm. Selection for increased piglet

  7. Survival analysis II: Cox regression

    NARCIS (Netherlands)

    Stel, Vianda S.; Dekker, Friedo W.; Tripepi, Giovanni; Zoccali, Carmine; Jager, Kitty J.

    2011-01-01

    In contrast to the Kaplan-Meier method, Cox proportional hazards regression can provide an effect estimate by quantifying the difference in survival between patient groups and can adjust for confounding effects of other variables. The purpose of this article is to explain the basic concepts of the

  8. Environmental survival of Neisseria meningitidis.

    Science.gov (United States)

    Tzeng, Y-L; Martin, L E; Stephens, D S

    2014-01-01

    Neisseria meningitidis is transmitted through the inhalation of large human respiratory droplets, but the risk from contaminated environmental surfaces is controversial. Compared to Streptococcus pneumoniae and Acinetobacter baumanni, meningococcal viability after desiccation on plastic, glass or metal surfaces decreased rapidly, but viable meningococci were present for up to 72 h. Encapsulation did not provide an advantage for meningococcal environmental survival on environmental surfaces.

  9. Survivability of SCADA Control Loop

    NARCIS (Netherlands)

    Camacho, José; de Boer, Pieter-Tjerk; Remke, Anne Katharina Ingrid

    2009-01-01

    The endorsement of information technologies for critical infrastructures control introduces new threats in their security and surveillance. Along with certain level of protection against attacks, it is desirable for critical processes to survive even if they succeed. A stochastic Petri Nets-based

  10. Human pathogen shown to cause disease in the threatened eklhorn coral Acropora palmata.

    Directory of Open Access Journals (Sweden)

    Kathryn Patterson Sutherland

    Full Text Available Coral reefs are in severe decline. Infections by the human pathogen Serratia marcescens have contributed to precipitous losses in the common Caribbean elkhorn coral, Acropora palmata, culminating in its listing under the United States Endangered Species Act. During a 2003 outbreak of this coral disease, called acroporid serratiosis (APS, a unique strain of the pathogen, Serratia marcescens strain PDR60, was identified from diseased A. palmata, human wastewater, the non-host coral Siderastrea siderea and the corallivorous snail Coralliophila abbreviata. In order to examine humans as a source and other marine invertebrates as vectors and/or reservoirs of the APS pathogen, challenge experiments were conducted with A. palmata maintained in closed aquaria to determine infectivity of strain PDR60 from reef and wastewater sources. Strain PDR60 from wastewater and diseased A. palmata caused disease signs in elkhorn coral in as little as four and five days, respectively, demonstrating that wastewater is a definitive source of APS and identifying human strain PDR60 as a coral pathogen through fulfillment of Koch's postulates. A. palmata inoculated with strain PDR60 from C. abbreviata showed limited virulence, with one of three inoculated fragments developing APS signs within 13 days. Strain PDR60 from non-host coral S. siderea showed a delayed pathogenic effect, with disease signs developing within an average of 20 days. These results suggest that C. abbreviata and non-host corals may function as reservoirs or vectors of the APS pathogen. Our results provide the first example of a marine "reverse zoonosis" involving the transmission of a human pathogen (S. marcescens to a marine invertebrate (A. palmata. These findings underscore the interaction between public health practices and environmental health indices such as coral reef survival.

  11. Task 1.5 Genomic Shift and Drift Trends of Emerging Pathogens

    Energy Technology Data Exchange (ETDEWEB)

    Borucki, M

    2010-01-05

    The Lawrence Livermore National Laboratory (LLNL) Bioinformatics group has recently taken on a role in DTRA's Transformation Medical Technologies Initiative (TMTI). The high-level goal of TMTI is to accelerate the development of broad-spectrum countermeasures. To achieve those goals, TMTI has a near term need to conduct analyses of genomic shift and drift trends of emerging pathogens, with a focused eye on select agent pathogens, as well as antibiotic and virulence markers. Most emerging human pathogens are zoonotic viruses with a genome composed of RNA. The high mutation rate of the replication enzymes of RNA viruses contributes to sequence drift and provides one mechanism for these viruses to adapt to diverse hosts (interspecies transmission events) and cause new human and zoonotic diseases. Additionally, new viral pathogens frequently emerge due to genetic shift (recombination and segment reassortment) which allows for dramatic genotypic and phenotypic changes to occur rapidly. Bacterial pathogens also evolve via genetic drift and shift, although sequence drift generally occurs at a much slower rate for bacteria as compared to RNA viruses. However, genetic shift such as lateral gene transfer and inter- and intragenomic recombination enables bacteria to rapidly acquire new mechanisms of survival and antibiotic resistance. New technologies such as rapid whole genome sequencing of bacterial genomes, ultra-deep sequencing of RNA virus populations, metagenomic studies of environments rich in antibiotic resistance genes, and the use of microarrays for the detection and characterization of emerging pathogens provide mechanisms to address the challenges posed by the rapid emergence of pathogens. Bioinformatic algorithms that enable efficient analysis of the massive amounts of data generated by these technologies as well computational modeling of protein structures and evolutionary processes need to be developed to allow the technology to fulfill its potential.

  12. Human pathogen shown to cause disease in the threatened eklhorn coral Acropora palmata.

    Science.gov (United States)

    Sutherland, Kathryn Patterson; Shaban, Sameera; Joyner, Jessica L; Porter, James W; Lipp, Erin K

    2011-01-01

    Coral reefs are in severe decline. Infections by the human pathogen Serratia marcescens have contributed to precipitous losses in the common Caribbean elkhorn coral, Acropora palmata, culminating in its listing under the United States Endangered Species Act. During a 2003 outbreak of this coral disease, called acroporid serratiosis (APS), a unique strain of the pathogen, Serratia marcescens strain PDR60, was identified from diseased A. palmata, human wastewater, the non-host coral Siderastrea siderea and the corallivorous snail Coralliophila abbreviata. In order to examine humans as a source and other marine invertebrates as vectors and/or reservoirs of the APS pathogen, challenge experiments were conducted with A. palmata maintained in closed aquaria to determine infectivity of strain PDR60 from reef and wastewater sources. Strain PDR60 from wastewater and diseased A. palmata caused disease signs in elkhorn coral in as little as four and five days, respectively, demonstrating that wastewater is a definitive source of APS and identifying human strain PDR60 as a coral pathogen through fulfillment of Koch's postulates. A. palmata inoculated with strain PDR60 from C. abbreviata showed limited virulence, with one of three inoculated fragments developing APS signs within 13 days. Strain PDR60 from non-host coral S. siderea showed a delayed pathogenic effect, with disease signs developing within an average of 20 days. These results suggest that C. abbreviata and non-host corals may function as reservoirs or vectors of the APS pathogen. Our results provide the first example of a marine "reverse zoonosis" involving the transmission of a human pathogen (S. marcescens) to a marine invertebrate (A. palmata). These findings underscore the interaction between public health practices and environmental health indices such as coral reef survival.

  13. Enteric bacterial pathogen detection in southern sea otters (Enhydra lutris nereis) is associated with coastal urbanization and freshwater runoff.

    Science.gov (United States)

    Miller, Melissa A; Byrne, Barbara A; Jang, Spencer S; Dodd, Erin M; Dorfmeier, Elene; Harris, Michael D; Ames, Jack; Paradies, David; Worcester, Karen; Jessup, David A; Miller, Woutrina A

    2010-01-01

    Although protected for nearly a century, California's sea otters have been slow to recover, in part due to exposure to fecally-associated protozoal pathogens like Toxoplasma gondii and Sarcocystis neurona. However, potential impacts from exposure to fecal bacteria have not been systematically explored. Using selective media, we examined feces from live and dead sea otters from California for specific enteric bacterial pathogens (Campylobacter, Salmonella, Clostridium perfringens, C. difficile and Escherichia coli O157:H7), and pathogens endemic to the marine environment (Vibrio cholerae, V. parahaemolyticus and Plesiomonas shigelloides). We evaluated statistical associations between detection of these pathogens in otter feces and demographic or environmental risk factors for otter exposure, and found that dead otters were more likely to test positive for C. perfringens, Campylobacter and V. parahaemolyticus than were live otters. Otters from more urbanized coastlines and areas with high freshwater runoff (near outflows of rivers or streams) were more likely to test positive for one or more of these bacterial pathogens. Other risk factors for bacterial detection in otters included male gender and fecal samples collected during the rainy season when surface runoff is maximal. Similar risk factors were reported in prior studies of pathogen exposure for California otters and their invertebrate prey, suggesting that land-sea transfer and/or facilitation of pathogen survival in degraded coastal marine habitat may be impacting sea otter recovery. Because otters and humans share many of the same foods, our findings may also have implications for human health.

  14. Enteric bacterial pathogen detection in southern sea otters (Enhydra lutris nereis) is associated with coastal urbanization and freshwater runoff

    Science.gov (United States)

    Miller, Melissa A.; Byrne, Barbara A.; Jang, Spencer S.; Dodd, Erin M.; Dorfmeier, Elene; Harris, Michael D.; Ames, Jack; Paradies, David; Worcester, Karen; Jessup, David A.; Miller, Woutrina A.

    2009-01-01

    Although protected for nearly a century, California’s sea otters have been slow to recover, in part due to exposure to fecally-associated protozoal pathogens like Toxoplasma gondii and Sarcocystis neurona. However, potential impacts from exposure to fecal bacteria have not been systematically explored. Using selective media, we examined feces from live and dead sea otters from California for specific enteric bacterial pathogens (Campylobacter, Salmonella, Clostridium perfringens, C. difficile and Escherichia coli O157:H7), and pathogens endemic to the marine environment (Vibrio cholerae, V. parahaemolyticus and Plesiomonas shigelloides). We evaluated statistical associations between detection of these pathogens in otter feces and demographic or environmental risk factors for otter exposure, and found that dead otters were more likely to test positive for C. perfringens, Campylobacter and V. parahaemolyticus than were live otters. Otters from more urbanized coastlines and areas with high freshwater runoff (near outflows of rivers or streams) were more likely to test positive for one or more of these bacterial pathogens. Other risk factors for bacterial detection in otters included male gender and fecal samples collected during the rainy season when surface runoff is maximal. Similar risk factors were reported in prior studies of pathogen exposure for California otters and their invertebrate prey, suggesting that land-sea transfer and/or facilitation of pathogen survival in degraded coastal marine habitat may be impacting sea otter recovery. Because otters and humans share many of the same foods, our findings may also have implications for human health. PMID:19720009

  15. A novel approach for differentiating pathogenic and non-pathogenic Leptospira based on molecular fingerprinting.

    Science.gov (United States)

    Xiao, Di; Zhang, Cuicai; Zhang, Huifang; Li, Xiuwen; Jiang, Xiugao; Zhang, Jianzhong

    2015-04-24

    Leptospirosis is a worldwide, deadly zoonotic disease. Pathogenic Leptospira causes leptospirosis. The rapid and accurate identification of pathogenic and non-pathogenic Leptospira strains is essential for appropriate therapeutic management and timely intervention for infection control. The molecular fingerprint is a simple and rapid alternative tool for microorganisms identification, which is based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). In this study, molecular fingerprint was performed to identify pathogenic strains of Leptospira. Phylogenetic analysis based on 16S rRNA gene sequences was used as the reference method. In addition, a label-free technique was used to reveal the different proteins of pathogenic or non-pathogenic Leptospira. A reference database was constructed using 30 Leptospira strains, including 16 pathogenic strains and 14 non-pathogenic strains. Two super reference spectra that were associated with pathogenicity were established. Overall, 33 Leptospira strains were used for validation, and 32 of 33 Leptospira strains could be identified on the species level and all the 33 could be classified as pathogenic or non-pathogenic. The super reference spectra and the major spectra projection (MSP) dendrogram correctly categorized the Leptospira strains into pathogenic and non-pathogenic groups, which was consistent with the 16S rRNA reference methods. Between the pathogenic and non-pathogenic strains, 108 proteins were differentially expressed. molecular fingerprint is an alternative to conventional molecular identification and can rapidly distinguish between pathogenic and non-pathogenic Leptospira strains. Therefore, molecular fingerprint may play an important role in the clinical diagnosis, treatment, surveillance, and tracking of epidemic outbreaks of leptospirosis. Leptospirosis is a worldwide zoonosis that is caused by spirochetes of the genus Leptospira. Leptospirosis is a serious zoonotic

  16. Pathogen reduction in sludges by irradiation

    International Nuclear Information System (INIS)

    Brandon, J.R.

    1978-01-01

    This paper presents results of pathogen inactivation programs being conducted in Belgium, Czechoslovakia, France, East Germany, West Germany, Hungary, Italy, The Netherlands, Poland, Spain, Sweden, Switzerland, the United Kingdom, and the United States

  17. Land application of sewage sludge: Pathogen issues

    Energy Technology Data Exchange (ETDEWEB)

    Chang, A C [Department of Soil and Environmental Sciences, Univ. of California at Riverside, Riverside, CA (United States)

    1997-10-01

    Diseases transmitted via the faecal-oral exposure route cause severe gastroenteric disorders, and large numbers of causative organisms are discharged with the faecal matter of infected individuals. For this reason, pathogenic bacteria, viruses, protozoa, or helminths, are always found in sewage sludge. If not properly treated for use in agriculture, sludge can be a source of pathogenic contamination. Radiation is an attractive method to reduce the numbers of microorganisms in sewage sludge. Routine examination for pathogens is not practised nor recommended because complicated and costly procedures are involved. Instead, an indicator organism is usually assayed and enumerated. In this paper, methods are discussed for the investigation of pathogens in sewage sludge. (author). 8 refs, 3 tabs.

  18. Genomes of foodborne and waterborne pathogens

    National Research Council Canada - National Science Library

    Fratamico, Pina M; Liu, Yanhong; Kathariou, Sophia

    2011-01-01

    ... of Pathogenic Vibrio cholerae * 85 Salvador Almagro-Moreno, Ronan A. Murphy, and E. Fidelma Boyd 8. Genomics of the Enteropathogenic Yersiniae * 101 Alan McNally, Nicholas R. Thomson, and Brendan W. ...

  19. Antibiotic resistance and pathogenicity factors in Staphylococcus ...

    Indian Academy of Sciences (India)

    know which endemic strains of S. aureus in dairy cattle ... Antibiotic resistance; cattle; mastitis; MRSA; pathogenic genes ... recommended by Clinical and Laboratory Standards Institute ...... fnbA, eno, hla and nuc, did not show any relation to.

  20. Exposure Control--OSHA's Bloodborne Pathogens Standard.

    Science.gov (United States)

    Granville, Mark F.

    1993-01-01

    Explains schools' responsibilities in complying with the Occupational Safety and Health Administration's (OSHA) Bloodborne Pathogens Standard. Describes exposure determination plan, protective equipment, housekeeping practices, labeling of waste, training employees, hepatitis B vaccinations, postexposure evaluation and medical follow-up, and…

  1. Persistence and drug tolerance in pathogenic yeast

    DEFF Research Database (Denmark)

    Bojsen, Rasmus Kenneth; Regenberg, Birgitte; Folkesson, Sven Anders

    2017-01-01

    In this review, we briefly summarize the current understanding of how fungal pathogens can persist antifungal treatment without heritable resistance mutations by forming tolerant persister cells. Fungal infections tolerant to antifungal treatment have become a major medical problem. One mechanism...

  2. Promotion and inhibition of mutation in pathogens

    Directory of Open Access Journals (Sweden)

    Maurice Samuel Devaraj

    2014-03-01

    Findings from this research may be used to prevent development of drug resistance, whether epigenetic or arising due to deoxyribonucleic acid (DNA modification, in several pathogens, especially Mycobacterium tuberculosis through the co-administration of adenosine along with antibiotic treatment.

  3. Modulation of pathogen recognition by autophagy

    Directory of Open Access Journals (Sweden)

    Ji Eun eOh

    2012-03-01

    Full Text Available Autophagy is an ancient biological process for maintaining cellular homeostasis by degradation of long-lived cytosolic proteins and organelles. Recent studies demonstrated that autophagy is availed by immune cells to regulate innate immunity. On the one hand, cells exert direct effector function by degrading intracellular pathogens; on the other hand, autophagy modulates pathogen recognition and downstream signaling for innate immune responses. Pathogen recognition via pattern recognition receptors induces autophagy. The function of phagocytic cells is enhanced by recruitment of autophagy-related proteins. Moreover, autophagy acts as a delivery system for viral replication complexes to migrate to the endosomal compartments where virus sensing occurs. In another case, key molecules of the autophagic pathway have been found to negatively regulate immune signaling, thus preventing aberrant activation of cytokine production and consequent immune responses. In this review, we focus on the recent advances in the role of autophagy in pathogen recognition and modulation of innate immune responses.

  4. Dietary proteins extend the survival of salmonella dublin in a gastric Acid environment

    DEFF Research Database (Denmark)

    Birk, Tina; Kristensen, Kim; Harboe, Anne

    2012-01-01

    The pH of the human stomach is dynamic and changes over time, depending on the composition of the food ingested and a number of host-related factors such as age. To evaluate the number of bacteria surviving the gastric acid barrier, we have developed a simple gastric acid model, in which we...... mimicked the dynamic pH changes in the human stomach. In the present study, model gastric fluid was set up to imitate pH dynamics in the stomachs of young and elderly people after ingestion of a standard meal. To model a serious foodborne pathogen, we followed the survival of Salmonella enterica serotype...

  5. Pathogen Causing Disease of Diagnosis PCR Tecnology

    OpenAIRE

    SEVİNDİK, Emre; KIR, A. Çağrı; BAŞKEMER, Kadir; UZUN, Veysel

    2013-01-01

    Polimerase chain reaction (PCR) with which, the development of recombinant DNA tecnology, a technique commonly used in field of moleculer biology and genetic. Duplication of the target DNA is provided with this technique without the need for cloning. Some fungus species, bacteria, viruses constitutent an important group of pathogenicity in human, animals and plants. There are routinely applied types of PCR in the detection of pathogens infections diseases. These Nested- PCR, Real- Time PCR, M...

  6. Adaptive value of sex in microbial pathogens.

    Science.gov (United States)

    Michod, Richard E; Bernstein, Harris; Nedelcu, Aurora M

    2008-05-01

    Explaining the adaptive value of sex is one of the great outstanding problems in biology. The challenge comes from the difficulty in identifying the benefits provided by sex, which must outweigh the substantial costs of sex. Here, we consider the adaptive value of sex in viruses, bacteria and fungi, and particularly the information available on the adaptive role of sex in pathogenic microorganisms. Our general theme is that the varied aspects of sex in pathogens illustrate the varied issues surrounding the evolution of sex generally. These include, the benefits of sex (in the short- and long-term), as well as the costs of sex (both to the host and to the pathogen). For the benefits of sex (that is, its adaptive value), we consider three hypotheses: (i) sex provides for effective and efficient recombinational repair of DNA damages, (ii) sex provides DNA for food, and (iii) sex produces variation and reduces genetic associations among alleles under selection. Although the evolution of sex in microbial pathogens illustrates these general issues, our paper is not a general review of theories for the evolution of sex in all organisms. Rather, we focus on the adaptive value of sex in microbial pathogens and conclude that in terms of short-term benefits, the DNA repair hypothesis has the most support and is the most generally applicable hypothesis in this group. In particular, recombinational repair of DNA damages may substantially benefit pathogens when challenged by the oxidative defenses of the host. However, in the long-term, sex may help get rid of mutations, increase the rate of adaptation of the population, and, in pathogens, may infrequently create new infective strains. An additional general issue about sex illustrated by pathogens is that some of the most interesting consequences of sex are not necessarily the reasons for which sex evolved. For example, antibiotic resistance may be transferred by bacterial sex, but this transfer is probably not the reason sex

  7. Identification of periodontal pathogens in atherosclerotic vessels

    DEFF Research Database (Denmark)

    Fiehn, Nils-Erik; Larsen, Tove; Christiansen, Natalia

    2005-01-01

    Epidemiological studies have shown that periodontitis may be associated with presence of atherosclerosis. DNA from periodontal pathogens has been detected in atherosclerotic lesions, but viable oral bacteria have not yet been isolated from atherosclerotic plaques. The purpose of the present study...... was to determine if viable oral bacteria could be isolated from atherosclerotic lesions and if DNA from periodontal pathogens could be detected by use of polymerase chain reaction (PCR) techniques....

  8. The cuticle and plant defense to pathogens

    Directory of Open Access Journals (Sweden)

    Jean-Pierre eMetraux

    2014-06-01

    Full Text Available The cuticle provides a physical barrier against water loss and protects against irradiation, xenobiotics and pathogens. Components of the cuticle are perceived by invading fungi and activate developmental processes during pathogenesis. In addition, cuticle alterations of various types induce a syndrome of reactions that often results in resistance to necrotrophs. This article reviews the current knowledge on the role of the cuticle in relation to the perception of pathogens and activation of defenses.

  9. Soil moisture and temperature conditions affect survival and sporulation capacity of Rhododendron leaf disks infested with Phytophthora ramorum

    Science.gov (United States)

    Ebba K. Peterson; Niklaus J. Grünwald; Jennifer L. ParkeSoil

    2017-01-01

    Soilborne inoculum (infested leaf debris which has become incorporated into the soil) may be an important contributor to the persistence of the sudden oak death pathogen Phytophthora ramorum in recurrently positive nurseries. To initiate new epidemics, soilborne inoculum must not only be able to survive over time, but also be capable of...

  10. No benefit in diversity? The effect of genetic variation on survival and disease resistance in a polygynous social insect

    DEFF Research Database (Denmark)

    Schmidt, Anna Mosegaard; Linksvayer, Timothy Arnold; Boomsma, Jacobus Jan

    2011-01-01

    within-worker variation).3. We found significant differences in worker survival among the three inbred lineages, with exposure to conidiospores of the fungal pathogen Beauveria bassiana causing significant mortality to the workers independently of their diversity type. Increased diversity did not improve...

  11. Adenoid Reservoir for Pathogenic Biofilm Bacteria▿

    Science.gov (United States)

    Nistico, L.; Kreft, R.; Gieseke, A.; Coticchia, J. M.; Burrows, A.; Khampang, P.; Liu, Y.; Kerschner, J. E.; Post, J. C.; Lonergan, S.; Sampath, R.; Hu, F. Z.; Ehrlich, G. D.; Stoodley, P.; Hall-Stoodley, L.

    2011-01-01

    Biofilms of pathogenic bacteria are present on the middle ear mucosa of children with chronic otitis media (COM) and may contribute to the persistence of pathogens and the recalcitrance of COM to antibiotic treatment. Controlled studies indicate that adenoidectomy is effective in the treatment of COM, suggesting that the adenoids may act as a reservoir for COM pathogens. To investigate the bacterial community in the adenoid, samples were obtained from 35 children undergoing adenoidectomy for chronic OM or obstructive sleep apnea. We used a novel, culture-independent molecular diagnostic methodology, followed by confocal microscopy, to investigate the in situ distribution and organization of pathogens in the adenoids to determine whether pathogenic bacteria exhibited criteria characteristic of biofilms. The Ibis T5000 Universal Biosensor System was used to interrogate the extent of the microbial diversity within adenoid biopsy specimens. Using a suite of 16 broad-range bacterial primers, we demonstrated that adenoids from both diagnostic groups were colonized with polymicrobial biofilms. Haemophilus influenzae was present in more adenoids from the COM group (P = 0.005), but there was no significant difference between the two patient groups for Streptococcus pneumoniae or Staphylococcus aureus. Fluorescence in situ hybridization, lectin binding, and the use of antibodies specific for host epithelial cells demonstrated that pathogens were aggregated, surrounded by a carbohydrate matrix, and localized on and within the epithelial cell surface, which is consistent with criteria for bacterial biofilms. PMID:21307211

  12. Regulatory T cells and immunity to pathogens.

    Science.gov (United States)

    Rouse, Barry T; Suvas, Susmit

    2007-09-01

    Immune responses to pathogens are modulated by one or more types of cells that perform a regulatory function. Some cells with this function, such as CD4+ Foxp3+ natural regulatory T cells (nTreg), pre-exist prior to infections whereas others may be induced as a consequence of infection (adaptive Treg). With pathogens that have a complex pathogenesis, multiple types of regulatory cells could influence the outcome. One major property of Treg is to help minimize collateral tissue damage that can occur during immune reactions to a chronic infection. The consequence is less damage to the host but in such situations the pathogen is likely to establish persistence. In some cases, a fine balance is established between Treg responses, effector components of immunity and the pathogen. Treg responses to pathogens may also act to hamper the efficacy of immune control. This review discusses these issues as well as the likely mechanisms by which various pathogens can signal the participation of Treg during infection.

  13. Sexual Reproduction of Human Fungal Pathogens

    Science.gov (United States)

    Heitman, Joseph; Carter, Dee A.; Dyer, Paul S.; Soll, David R.

    2014-01-01

    We review here recent advances in our understanding of sexual reproduction in fungal pathogens that commonly infect humans, including Candida albicans, Cryptococcus neoformans/gattii, and Aspergillus fumigatus. Where appropriate or relevant, we introduce findings on other species associated with human infections. In particular, we focus on rapid advances involving genetic, genomic, and population genetic approaches that have reshaped our view of how fungal pathogens evolve. Rather than being asexual, mitotic, and largely clonal, as was thought to be prevalent as recently as a decade ago, we now appreciate that the vast majority of pathogenic fungi have retained extant sexual, or parasexual, cycles. In some examples, sexual and parasexual unions of pathogenic fungi involve closely related individuals, generating diversity in the population but with more restricted recombination than expected from fertile, sexual, outcrossing and recombining populations. In other cases, species and isolates participate in global outcrossing populations with the capacity for considerable levels of gene flow. These findings illustrate general principles of eukaryotic pathogen emergence with relevance for other fungi, parasitic eukaryotic pathogens, and both unicellular and multicellular eukaryotic organisms. PMID:25085958

  14. The Intriguing Evolutionary Journey of Enteroinvasive E. coli (EIEC) toward Pathogenicity.

    Science.gov (United States)

    Pasqua, Martina; Michelacci, Valeria; Di Martino, Maria Letizia; Tozzoli, Rosangela; Grossi, Milena; Colonna, Bianca; Morabito, Stefano; Prosseda, Gianni

    2017-01-01

    Among the intestinal pathogenic Escherichia coli , enteroinvasive E. coli (EIEC) are a group of intracellular pathogens able to enter epithelial cells of colon, multiplicate within them, and move between adjacent cells with a mechanism similar to Shigella , the ethiological agent of bacillary dysentery. Despite EIEC belong to the same pathotype of Shigella , they neither have the full set of traits that define Shigella nor have undergone the extensive gene decay observed in Shigella . Molecular analysis confirms that EIEC are widely distributed among E. coli phylogenetic groups and correspond to bioserotypes found in many E. coli serogroups. Like Shigella , also in EIEC the critical event toward a pathogenic life-style consisted in the acquisition by horizontal gene transfer of a large F-type plasmid (pINV) containing the genes required for invasion, intracellular survival, and spreading through the intestinal mucosa. In Shigella , the ample gain in virulence determinants has been counteracted by a substantial loss of functions that, although important for the survival in the environment, are redundant or deleterious for the life inside the host. The pathoadaptation process that has led Shigella to modify its metabolic profile and increase its pathogenic potential is still in infancy in EIEC, although maintenance of some features typical of E. coli might favor their emerging relevance as intestinal pathogens worldwide, as documented by recent outbreaks in industrialized countries. In this review, we will discuss the evolution of EIEC toward Shigella -like invasive forms going through the epidemiology, including the emergence of new virulent strains, their genome organization, and the complex interactions they establish with the host.

  15. The Intriguing Evolutionary Journey of Enteroinvasive E. coli (EIEC toward Pathogenicity

    Directory of Open Access Journals (Sweden)

    Martina Pasqua

    2017-12-01

    Full Text Available Among the intestinal pathogenic Escherichia coli, enteroinvasive E. coli (EIEC are a group of intracellular pathogens able to enter epithelial cells of colon, multiplicate within them, and move between adjacent cells with a mechanism similar to Shigella, the ethiological agent of bacillary dysentery. Despite EIEC belong to the same pathotype of Shigella, they neither have the full set of traits that define Shigella nor have undergone the extensive gene decay observed in Shigella. Molecular analysis confirms that EIEC are widely distributed among E. coli phylogenetic groups and correspond to bioserotypes found in many E. coli serogroups. Like Shigella, also in EIEC the critical event toward a pathogenic life-style consisted in the acquisition by horizontal gene transfer of a large F-type plasmid (pINV containing the genes required for invasion, intracellular survival, and spreading through the intestinal mucosa. In Shigella, the ample gain in virulence determinants has been counteracted by a substantial loss of functions that, although important for the survival in the environment, are redundant or deleterious for the life inside the host. The pathoadaptation process that has led Shigella to modify its metabolic profile and increase its pathogenic potential is still in infancy in EIEC, although maintenance of some features typical of E. coli might favor their emerging relevance as intestinal pathogens worldwide, as documented by recent outbreaks in industrialized countries. In this review, we will discuss the evolution of EIEC toward Shigella-like invasive forms going through the epidemiology, including the emergence of new virulent strains, their genome organization, and the complex interactions they establish with the host.

  16. Pathogenicity of Human ST23 Streptococcus agalactiae to Fish and Genomic Comparison of Pathogenic and Non-pathogenic Isolates

    Directory of Open Access Journals (Sweden)

    Rui Wang

    2017-10-01

    Full Text Available Streptococcus agalactiae, or Group B Streptococcus (GBS, is a major pathogen causing neonatal sepsis and meningitis, bovine mastitis, and fish meningoencephalitis. CC23, including its namesake ST23, is not only the predominant GBS strain derived from human and cattle, but also can infect a variety of homeothermic and poikilothermic species. However, it has never been characterized in fish. This study aimed to determine the pathogenicity of ST23 GBS to fish and explore the mechanisms causing the difference in the pathogenicity of ST23 GBS based on the genome analysis. Infection of tilapia with 10 human-derived ST23 GBS isolates caused tissue damage and the distribution of pathogens within tissues. The mortality rate of infection was ranged from 76 to 100%, and it was shown that the mortality rate caused by only three human isolates had statistically significant difference compared with fish-derived ST7 strain (P < 0.05, whereas the mortality caused by other seven human isolates did not show significant difference compared with fish-derived ST7 strain. The genome comparison and prophage analysis showed that the major genome difference between virulent and non-virulent ST23 GBS was attributed to the different prophage sequences. The prophage in the P1 region contained about 43% GC and encoded 28–39 proteins, which can mediate the acquisition of YafQ/DinJ structure for GBS by phage recombination. YafQ/DinJ belongs to one of the bacterial toxin–antitoxin (TA systems and allows cells to cope with stress. The ST23 GBS strains carrying this prophage were not pathogenic to tilapia, but the strains without the prophage or carrying the pophage that had gene mutation or deletion, especially the deletion of YafQ/DinJ structure, were highly pathogenic to tilapia. In conclusion, human ST23 GBS is highly pathogenic to fish, which may be related to the phage recombination.

  17. Pathogenicity and Host Range of Pathogen Causing Black Raspberry (Rubus coreanus) Anthracnose in Korea

    OpenAIRE

    Uh Seong Jeong; Ju Hee Kim; Ki Kwon Lee; Seong Soo Cheong; Wang Hyu Lee

    2013-01-01

    The strains of Colletotrichum gloeosporioides, C. coccodes, C. acutatum isolated from black raspberry werepathogenic to apple and strawberry after dropping inoculation, but showed weak pathogenicity in hot-pepperand tomato. The anthracnose pathogens of C. gloeosporioides, C. orbiculare, C. acutatum isolated from apple,hot-pepper and pumpkin showed pathogenicity in black raspberry. Moreover, the anthracnose pathogensisolated from apple caused disease symptoms in non-wounded inoculation.

  18. Survival relative to new and ancestral host plants, phytoplasma infection, and genetic constitution in host races of a polyphagous insect disease vector

    Science.gov (United States)

    Maixner, Michael; Albert, Andreas; Johannesen, Jes

    2014-01-01

    Dissemination of vectorborne diseases depends strongly on the vector's host range and the pathogen's reservoir range. Because vectors interact with pathogens, the direction and strength of a vector's host shift is vital for understanding epidemiology and is embedded in the framework of ecological specialization. This study investigates survival in host-race evolution of a polyphagous insect disease vector, Hyalesthes obsoletus, whether survival is related to the direction of the host shift (from field bindweed to stinging nettle), the interaction with plant-specific strains of obligate vectored pathogens/symbionts (stolbur phytoplasma), and whether survival is related to genetic differentiation between the host races. We used a twice repeated, identical nested experimental design to study survival of the vector on alternative hosts and relative to infection status. Survival was tested with Kaplan–Meier analyses, while genetic differentiation between vector populations was quantified with microsatellite allele frequencies. We found significant direct effects of host plant (reduced survival on wrong hosts) and sex (males survive longer than females) in both host races and relative effects of host (nettle animals more affected than bindweed animals) and sex (males more affected than females). Survival of bindweed animals was significantly higher on symptomatic than nonsymptomatic field bindweed, but in the second experiment only. Infection potentially had a positive effect on survival in nettle animals but due to low infection rates the results remain suggestive. Genetic differentiation was not related to survival. Greater negative plant-transfer effect but no negative effect of stolbur in the derived host race suggests preadaptation to the new pathogen/symbiont strain before strong diversifying selection during the specialization process. Physiological maladaptation or failure to accept the ancestral plant will have similar consequences, namely positive assortative

  19. Pathogen Decay during Managed Aquifer Recharge at Four Sites with Different Geochemical Characteristics and Recharge Water Sources.

    Science.gov (United States)

    Sidhu, J P S; Toze, S; Hodgers, L; Barry, K; Page, D; Li, Y; Dillon, P

    2015-09-01

    Recycling of stormwater water and treated effluent via managed aquifer recharge (MAR) has often been hampered because of perceptions of low microbiological quality of recovered water and associated health risks. The goal of this study was to assess the removal of selected pathogens in four large-scale MAR schemes and to determine the influence of aquifer characteristics, geochemistry, and type of recharge water on the pathogen survival times. Bacterial pathogens tested in this study had the shortest one log removal time (, 200 d). Human adenovirus and rotavirus were relatively persistent under anaerobic conditions (, >200 d). Human adenovirus survived longer than all the other enteric virus tested in the study and hence could be used as a conservative indicator for virus removal in groundwater during MAR. The results suggest that site-specific subsurface conditions such as groundwater chemistry can have considerable influence on the decay rates of enteric pathogens and that viruses are likely to be the critical pathogens from a public health perspective. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  20. Age, pathogen exposure, but not maternal care shape offspring immunity in an insect with facultative family life.

    Science.gov (United States)

    Vogelweith, Fanny; Körner, Maximilian; Foitzik, Susanne; Meunier, Joël

    2017-03-07

    To optimize their resistance against pathogen infection, individuals are expected to find the right balance between investing into the immune system and other life history traits. In vertebrates, several factors were shown to critically affect the direction of this balance, such as the developmental stage of an individual, its current risk of infection and/or its access to external help such as parental care. However, the independent and/or interactive effects of these factors on immunity remain poorly studied in insects. Here, we manipulated maternal presence and pathogen exposure in families of the European earwig Forficula auricularia to measure whether and how the survival rate and investment into two key immune parameters changed during offspring development. The pathogen was the entomopathogenic fungus Metarhizium brunneum and the immune parameters were hemocyte concentration and phenol/pro-phenoloxidase enzyme activity (total-PO). Our results surprisingly showed that maternal presence had no effect on offspring immunity, but reduced offspring survival. Pathogen exposure also lowered the survival of offspring during their early development. The concentration of hemocytes and the total-PO activity increased during development, to be eventually higher in adult females compared to adult males. Finally, pathogen exposure overall increased the concentration of hemocytes-but not the total-PO activity-in adults, while it had no effect on these measures in offspring. Our results show that, independent of their infection risk and developmental stage, maternal presence does not shape immune defense in young earwigs. This reveals that pathogen pressure is not a universal evolutionary driver of the emergence and maintenance of post-hatching maternal care in insects.

  1. Intracellular survival of Staphylococcus aureus during persistent infection in the insect Tenebrio molitor.

    Science.gov (United States)

    McGonigle, John E; Purves, Joanne; Rolff, Jens

    2016-06-01

    Survival of bacteria within host cells and tissues presents a challenge to the immune systems of higher organisms. Escape from phagocytic immune cells compounds this issue, as immune cells become potential vehicles for pathogen dissemination. However, the duration of persistence within phagocytes and its contribution to pathogen load has yet to be determined. We investigate the immunological significance of intracellular persistence within the insect model Tenebrio molitor, assessing the extent, duration and location of bacterial recovery during a persistent infection. Relative abundance of Staphylococcus aureus in both intracellular and extracellular fractions was determined over 21 days, and live S. aureus were successfully recovered from both the hemolymph and within phagocytic immune cells across the entire time course. The proportion of bacteria recovered from within phagocytes also increased over time. Our results show that to accurately estimate pathogen load it is vital to account for bacteria persisting within immune cells. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. 51Cr - erythrocyte survival curves

    International Nuclear Information System (INIS)

    Paiva Costa, J. de.

    1982-07-01

    Sixteen patients were studied, being fifteen patients in hemolytic state, and a normal individual as a witness. The aim was to obtain better techniques for the analysis of the erythrocytes, survival curves, according to the recommendations of the International Committee of Hematology. It was used the radiochromatic method as a tracer. Previously a revisional study of the International Literature was made in its aspects inherent to the work in execution, rendering possible to establish comparisons and clarify phonomena observed in cur investigation. Several parameters were considered in this study, hindering both the exponential and the linear curves. The analysis of the survival curves of the erythrocytes in the studied group, revealed that the elution factor did not present a homogeneous answer quantitatively to all, though, the result of the analysis of these curves have been established, through listed programs in the electronic calculator. (Author) [pt

  3. Complexity for survival of livings

    International Nuclear Information System (INIS)

    Zak, Michail

    2007-01-01

    A connection between survivability of livings and complexity of their behavior is established. New physical paradigms-exchange of information via reflections, and chain of abstractions-explaining and describing progressive evolution of complexity in living (active) systems are introduced. A biological origin of these paradigms is associated with a recently discovered mirror neuron that is able to learn by imitation. As a result, an active element possesses the self-nonself images and interacts with them creating the world of mental dynamics. Three fundamental types of complexity of mental dynamics that contribute to survivability are identified. Mathematical model of the corresponding active systems is described by coupled motor-mental dynamics represented by Langevin and Fokker-Planck equations, respectively, while the progressive evolution of complexity is provided by nonlinear evolution of probability density. Application of the proposed formalism to modeling common-sense-based decision-making process is discussed

  4. Individual social capital and survival

    DEFF Research Database (Denmark)

    Ejlskov, Linda; Mortensen, Rikke N; Overgaard, Charlotte

    2014-01-01

    BACKGROUND: The concept of social capital has received increasing attention as a determinant of population survival, but its significance is uncertain. We examined the importance of social capital on survival in a population study while focusing on gender differences. METHODS: We used data from...... a Danish regional health survey with a five-year follow-up period, 2007-2012 (n = 9288, 53.5% men, 46.5% women). We investigated the association between social capital and all-cause mortality, performing separate analyses on a composite measure as well as four specific dimensions of social capital while...... controlling for covariates. Analyses were performed with Cox proportional hazard models by which hazard ratios and 95% confidence intervals were calculated. RESULTS: For women, higher levels of social capital were associated with lower all-cause mortality regardless of age, socioeconomic status, health...

  5. Complexity for survival of livings

    Energy Technology Data Exchange (ETDEWEB)

    Zak, Michail [Jet Propulsion Laboratory, California Institute of Technology, Advance Computing Algorithms and IVHM Group, Pasadena, CA 91109 (United States)]. E-mail: Michail.Zak@jpl.nasa.gov

    2007-05-15

    A connection between survivability of livings and complexity of their behavior is established. New physical paradigms-exchange of information via reflections, and chain of abstractions-explaining and describing progressive evolution of complexity in living (active) systems are introduced. A biological origin of these paradigms is associated with a recently discovered mirror neuron that is able to learn by imitation. As a result, an active element possesses the self-nonself images and interacts with them creating the world of mental dynamics. Three fundamental types of complexity of mental dynamics that contribute to survivability are identified. Mathematical model of the corresponding active systems is described by coupled motor-mental dynamics represented by Langevin and Fokker-Planck equations, respectively, while the progressive evolution of complexity is provided by nonlinear evolution of probability density. Application of the proposed formalism to modeling common-sense-based decision-making process is discussed.

  6. Saudi sands, SCUDS, and survival.

    Science.gov (United States)

    Glendon, M P

    1993-01-01

    SCUD attacks were one of many challenges this pediatric nurse practitioner (NP) and Air Force Reserve flight nurse faced daily during Desert Shield and Desert Storm. Providing nursing care to sick and injured patients on board a C141 transport plane en route from Saudi Arabia to Germany was her primary responsibility. Additionally, many hours were spent filling sandbags, attending in-service classes, and practicing putting on a gas mask and protective suit. Although the war has been over for almost 3 years, the effects are long lasting. The author was able to use her wartime experience positively to gain insight into survival in today's violent society. As violence increases, NPs must reshape their focus and educate their clients about survival.

  7. LATERAL SURVIVAL: AN OT ACCOUNT

    Directory of Open Access Journals (Sweden)

    Moira Yip

    2004-12-01

    Full Text Available When laterals are the targets of phonological processes, laterality may or may not survive. In a fixed feature geometry, [lateral] should be lost if its superordinate node is eliminated by either the spreading of a neighbouring node, or by coda neutralization. So if [lateral] is under Coronal (Blevins 1994, it should be lost under Place assimilation, and if [lateral] is under Sonorant Voicing (Rice & Avery 1991 it should be lost by rules that spread voicing. Yet in some languages lateral survives such spreading intact. Facts like these argue against a universal attachment of [lateral] under either Coronal or Sonorant Voicing, and in favour of an account in terms of markedness constraints on feature-co-occurrence (Padgett 2000. The core of an OT account is that IFIDENTLAT is ranked above whatever causes neutralization, such as SHARE-F or *CODAF. laterality will survive. If these rankings are reversed, we derive languages in which laterality is lost. The other significant factor is markedness. High-ranked feature co-occurrence constraints like *LATDORSAL can block spreading from affecting laterals at all.

  8. Effective but costly, evolved mechanisms of defense against a virulent opportunistic pathogen in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Yixin H Ye

    2009-04-01

    Full Text Available Drosophila harbor substantial genetic variation for antibacterial defense, and investment in immunity is thought to involve a costly trade-off with life history traits, including development, life span, and reproduction. To understand the way in which insects invest in fighting bacterial infection, we selected for survival following systemic infection with the opportunistic pathogen Pseudomonas aeruginosa in wild-caught Drosophila melanogaster over 10 generations. We then examined genome-wide changes in expression in the selected flies relative to unselected controls, both of which had been infected with the pathogen. This powerful combination of techniques allowed us to specifically identify the genetic basis of the evolved immune response. In response to selection, population-level survivorship to infection increased from 15% to 70%. The evolved capacity for defense was costly, however, as evidenced by reduced longevity and larval viability and a rapid loss of the trait once selection pressure was removed. Counter to expectation, we observed more rapid developmental rates in the selected flies. Selection-associated changes in expression of genes with dual involvement in developmental and immune pathways suggest pleiotropy as a possible mechanism for the positive correlation. We also found that both the Toll and the Imd pathways work synergistically to limit infectivity and that cellular immunity plays a more critical role in overcoming P. aeruginosa infection than previously reported. This work reveals novel pathways by which Drosophila can survive infection with a virulent pathogen that may be rare in wild populations, however, due to their cost.

  9. NAD+-Glycohydrolase Promotes Intracellular Survival of Group A Streptococcus.

    Directory of Open Access Journals (Sweden)

    Onkar Sharma

    2016-03-01

    Full Text Available A global increase in invasive infections due to group A Streptococcus (S. pyogenes or GAS has been observed since the 1980s, associated with emergence of a clonal group of strains of the M1T1 serotype. Among other virulence attributes, the M1T1 clone secretes NAD+-glycohydrolase (NADase. When GAS binds to epithelial cells in vitro, NADase is translocated into the cytosol in a process mediated by streptolysin O (SLO, and expression of these two toxins is associated with enhanced GAS intracellular survival. Because SLO is required for NADase translocation, it has been difficult to distinguish pathogenic effects of NADase from those of SLO. To resolve the effects of the two proteins, we made use of anthrax toxin as an alternative means to deliver NADase to host cells, independently of SLO. We developed a novel method for purification of enzymatically active NADase fused to an amino-terminal fragment of anthrax toxin lethal factor (LFn-NADase that exploits the avid, reversible binding of NADase to its endogenous inhibitor. LFn-NADase was translocated across a synthetic lipid bilayer in vitro in the presence of anthrax toxin protective antigen in a pH-dependent manner. Exposure of human oropharyngeal keratinocytes to LFn-NADase in the presence of protective antigen resulted in cytosolic delivery of NADase activity, inhibition of protein synthesis, and cell death, whereas a similar construct of an enzymatically inactive point mutant had no effect. Anthrax toxin-mediated delivery of NADase in an amount comparable to that observed during in vitro infection with live GAS rescued the defective intracellular survival of NADase-deficient GAS and increased the survival of SLO-deficient GAS. Confocal microscopy demonstrated that delivery of LFn-NADase prevented intracellular trafficking of NADase-deficient GAS to lysosomes. We conclude that NADase mediates cytotoxicity and promotes intracellular survival of GAS in host cells.

  10. Significance and survival of Enterococci during the house fly development.

    Science.gov (United States)

    Ghosh, Anuradha; Akhtar, Mastura; Holderman, Chris; Zurek, Ludek

    2014-01-01

    House flies are among the most important nonbiting insect pests of medical and veterinary importance. Larvae develop in decaying organic substrates and their survival strictly depends on an active microbial community. House flies have been implicated in the ecology and transmission of enterococci, including multi-antibiotic-resistant and virulent strains of Enterococcus faecalis. In this study, eight American Type Culture Collection type strains of enterococci including Enterococcus avium, Enterococcus casseliflavus, Enterococcus durans, Enterococcus hirae, Enterococcus mundtii, Enterococcus gallinarum, Enterococcusfaecalis, and Enterococcusfaecium were evaluated for their significance in the development of house flies from eggs to adults in bacterial feeding assays. Furthermore, the bacterial colonization of the gut of teneral flies as well as the importance of several virulence traits of E. faecalis in larval mortality was assessed. Overall survival of house flies (egg to adult) was significantly higher when grown with typically nonpathogenic enterococcal species such as E. hirae (76.0% survival), E. durans (64.0%), and E. avium (64.0%) compared with that with clinically important species E. faecalis (24.0%) and E. faecium (36.0%). However, no significant differences in survival of house fly larvae were detected when grown with E. faecalis strains carrying various virulence traits, including isogenic mutants of the human clinical isolate E. faecalis V583 with in-frame deletions of gelatinase, serine protease, and capsular polysaccharide serotype C. Enterococci were commonly detected in fly puparia (range: 75-100%; concentration: 103-105 CFU/puparium);however, the prevalence of enterococci in teneral flies varied greatly: from 25.0 (E. casseliflavus) to 89.5% (E. hirae). In conclusion, depending on the species, enterococci variably support house fly larval development and colonize the gut of teneral adults. The human pathogenic species, E. faecalis and E. faecium

  11. Electrochemical Methodologies for the Detection of Pathogens.

    Science.gov (United States)

    Amiri, Mandana; Bezaatpour, Abolfazl; Jafari, Hamed; Boukherroub, Rabah; Szunerits, Sabine

    2018-05-25

    Bacterial infections remain one of the principal causes of morbidity and mortality worldwide. The number of deaths due to infections is declining every year by only 1% with a forecast of 13 million deaths in 2050. Among the 1400 recognized human pathogens, the majority of infectious diseases is caused by just a few, about 20 pathogens only. While the development of vaccinations and novel antibacterial drugs and treatments are at the forefront of research, and strongly financially supported by policy makers, another manner to limit and control infectious outbreaks is targeting the development and implementation of early warning systems, which indicate qualitatively and quantitatively the presence of a pathogen. As toxin contaminated food and drink are a potential threat to human health and consequently have a significant socioeconomic impact worldwide, the detection of pathogenic bacteria remains not only a big scientific challenge but also a practical problem of enormous significance. Numerous analytical methods, including conventional culturing and staining techniques as well as molecular methods based on polymerase chain reaction amplification and immunological assays, have emerged over the years and are used to identify and quantify pathogenic agents. While being highly sensitive in most cases, these approaches are highly time, labor, and cost consuming, requiring trained personnel to perform the frequently complex assays. A great challenge in this field is therefore to develop rapid, sensitive, specific, and if possible miniaturized devices to validate the presence of pathogens in cost and time efficient manners. Electrochemical sensors are well accepted powerful tools for the detection of disease-related biomarkers and environmental and organic hazards. They have also found widespread interest in the last years for the detection of waterborne and foodborne pathogens due to their label free character and high sensitivity. This Review is focused on the current

  12. Pathogenicity island mobility and gene content.

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Kelly Porter

    2013-10-01

    Key goals towards national biosecurity include methods for analyzing pathogens, predicting their emergence, and developing countermeasures. These goals are served by studying bacterial genes that promote pathogenicity and the pathogenicity islands that mobilize them. Cyberinfrastructure promoting an island database advances this field and enables deeper bioinformatic analysis that may identify novel pathogenicity genes. New automated methods and rich visualizations were developed for identifying pathogenicity islands, based on the principle that islands occur sporadically among closely related strains. The chromosomally-ordered pan-genome organizes all genes from a clade of strains; gaps in this visualization indicate islands, and decorations of the gene matrix facilitate exploration of island gene functions. A %E2%80%9Clearned phyloblocks%E2%80%9D method was developed for automated island identification, that trains on the phylogenetic patterns of islands identified by other methods. Learned phyloblocks better defined termini of previously identified islands in multidrug-resistant Klebsiella pneumoniae ATCC BAA-2146, and found its only antibiotic resistance island.

  13. Deconstructing host-pathogen interactions in Drosophila

    Directory of Open Access Journals (Sweden)

    Ethan Bier

    2012-01-01

    Full Text Available Many of the cellular mechanisms underlying host responses to pathogens have been well conserved during evolution. As a result, Drosophila can be used to deconstruct many of the key events in host-pathogen interactions by using a wealth of well-developed molecular and genetic tools. In this review, we aim to emphasize the great leverage provided by the suite of genomic and classical genetic approaches available in flies for decoding details of host-pathogen interactions; these findings can then be applied to studies in higher organisms. We first briefly summarize the general strategies by which Drosophila resists and responds to pathogens. We then focus on how recently developed genome-wide RNA interference (RNAi screens conducted in cells and flies, combined with classical genetic methods, have provided molecular insight into host-pathogen interactions, covering examples of bacteria, fungi and viruses. Finally, we discuss novel strategies for how flies can be used as a tool to examine how specific isolated virulence factors act on an intact host.

  14. PIML: the Pathogen Information Markup Language.

    Science.gov (United States)

    He, Yongqun; Vines, Richard R; Wattam, Alice R; Abramochkin, Georgiy V; Dickerman, Allan W; Eckart, J Dana; Sobral, Bruno W S

    2005-01-01

    A vast amount of information about human, animal and plant pathogens has been acquired, stored and displayed in varied formats through different resources, both electronically and otherwise. However, there is no community standard format for organizing this information or agreement on machine-readable format(s) for data exchange, thereby hampering interoperation efforts across information systems harboring such infectious disease data. The Pathogen Information Markup Language (PIML) is a free, open, XML-based format for representing pathogen information. XSLT-based visual presentations of valid PIML documents were developed and can be accessed through the PathInfo website or as part of the interoperable web services federation known as ToolBus/PathPort. Currently, detailed PIML documents are available for 21 pathogens deemed of high priority with regard to public health and national biological defense. A dynamic query system allows simple queries as well as comparisons among these pathogens. Continuing efforts are being taken to include other groups' supporting PIML and to develop more PIML documents. All the PIML-related information is accessible from http://www.vbi.vt.edu/pathport/pathinfo/

  15. Susceptibility of pathogenic and nonpathogenic Naegleria ssp

    International Nuclear Information System (INIS)

    Whiteman, L.Y.

    1988-01-01

    The susceptibility of four species of Naegleria amoebae to complement-mediated lysis was determined. The amoebicidal activity of normal human serum (NHS) and normal guinea pig serum (NGPS) for Naegleria amoebae was measured by an in vitro cytotoxicity assay. Release of radioactivity from amoebae labeled with 3 H-uridine and visual observation with a compound microscope were used as indices of lysis. Susceptibility or resistance to complement-mediated lysis in vitro correlated with the in vivo pathogenic potential. Nonpathogenic Naegleria amoebae were lysed at a faster rate and at higher cell concentrations than were pathogenic amoebae. Electrophoretic analysis of NHS incubated with pathogenic or nonpathogenic Naegleria spp. demonstrated that amoebae activate the complement cascade resulting in the production of C3 and C5 complement cleavage products. Treatment with papain or trypsin for 1 h, but not with sialidase, increase the susceptibility of highly pathogenic, mouse-passaged N. fowleri to lysis. Treatment with actinomycin D, cycloheximide or various protease inhibitors for 4 h did not increase susceptibility to lysis. Neither a repair process involving de novo protein synthesis nor a complement-inactivating protease appear to account for the increase resistance of N. fowleri amoebae to complement-mediated lysis. A binding study with 125 I radiolabeled C9 indicated that the terminal complement component does not remain stably bound to the membrane of pathogenic amoebae

  16. Regulatory Proteolysis in Arabidopsis-Pathogen Interactions.

    Science.gov (United States)

    Pogány, Miklós; Dankó, Tamás; Kámán-Tóth, Evelin; Schwarczinger, Ildikó; Bozsó, Zoltán

    2015-09-24

    Approximately two and a half percent of protein coding genes in Arabidopsis encode enzymes with known or putative proteolytic activity. Proteases possess not only common housekeeping functions by recycling nonfunctional proteins. By irreversibly cleaving other proteins, they regulate crucial developmental processes and control responses to environmental changes. Regulatory proteolysis is also indispensable in interactions between plants and their microbial pathogens. Proteolytic cleavage is simultaneously used both by plant cells, to recognize and inactivate invading pathogens, and by microbes, to overcome the immune system of the plant and successfully colonize host cells. In this review, we present available results on the group of proteases in the model plant Arabidopsis thaliana whose functions in microbial pathogenesis were confirmed. Pathogen-derived proteolytic factors are also discussed when they are involved in the cleavage of host metabolites. Considering the wealth of review papers available in the field of the ubiquitin-26S proteasome system results on the ubiquitin cascade are not presented. Arabidopsis and its pathogens are conferred with abundant sets of proteases. This review compiles a list of those that are apparently involved in an interaction between the plant and its pathogens, also presenting their molecular partners when available.

  17. Priority setting of foodborne pathogens: disease burden and costs of selected enteric pathogens

    NARCIS (Netherlands)

    Kemmeren JM; Mangen MJJ; Duynhoven YTHP van; Havelaar AH; MGB

    2006-01-01

    Toxoplasmosis causes the highest disease burden among seven evaluated foodborne pathogens. This is the preliminary conclusion of a major study of the disease burden and related costs of foodborne pathogens. The other micro-organisms that were studied are Campylobacter spp., Salmonella spp.,

  18. Methods for detecting pathogens in the beef food chain: detecting particular pathogens

    Science.gov (United States)

    The main food-borne pathogens of concern in the beef food chain are Shiga toxin-producing Escherichia coli (STEC) and Salmonella spp.; however, the presence of other pathogens, including Listeria monocytogenes, Campylobacter spp., Clostridium spp., Bacillus cereus, and Mycobacterium avium subsp. par...

  19. Host-pathogen interactions and genome evolution in two generalist and specialist microsporidian pathogens of mosquitoes

    Science.gov (United States)

    The adaptation of two distantly related microsporidia to their mosquito hosts was investigated. Edhazardia aedis is a specialist pathogen that infects Aedes aegypti, the main vector of dengue and yellow fever arboviruses. Vavraia culicis is a generalist pathogen of several insects including Anophele...

  20. Assessing the consequences of global change for forest disturbance from herbivores and pathogens.

    Science.gov (United States)

    Ayres, M P; Lombardero, M J

    2000-11-15

    Herbivores and pathogens impact the species composition, ecosystem function, and socioeconomic value of forests. Herbivores and pathogens are an integral part of forests, but sometimes produce undesirable effects and a degradation of forest resources. In the United States, a few species of forest pests routinely have significant impacts on up to 20 million ha of forest with economic costs that probably exceed $1 billion/year. Climatic change could alter patterns of disturbance from herbivores and pathogens through: (1) direct effects on the development and survival of herbivores and pathogens; (2) physiological changes in tree defenses; and (3) indirect effects from changes in the abundance of natural enemies (e.g. parasitoids of insect herbivores), mutualists (e.g. insect vectors of tree pathogens), and competitors. Because of their short life cycles, mobility, reproductive potential, and physiological sensitivity to temperature, even modest climate change will have rapid impacts on the distribution and abundance of many forest insects and pathogens. We identify 32 syndromes of biotic disturbance in North American forests that should be carefully evaluated for their responses to climate change: 15 insect herbivores, browsing mammals; 12 pathogens; 1 plant parasite; and 3 undiagnosed patterns of forest decline. It is probable that climatic effects on some herbivores and pathogens will impact on biodiversity, recreation, property value, forest industry, and even water quality. Some scenarios are beneficial (e.g. decreased snow cover may increase winter mortality of some insect pests), but many are detrimental (e.g. warming tends to accelerate insect development rate and facilitate range expansions of pests and climate change tends to produce a mismatch between mature trees and their environment, which can increase vulnerability to herbivores and pathogens). Changes in forest disturbance can produce feedback to climate through affects on water and carbon flux in

  1. Genetic recombination between human and animal parasites creates novel strains of human pathogen.

    Directory of Open Access Journals (Sweden)

    Wendy Gibson

    2015-03-01

    Full Text Available Genetic recombination between pathogens derived from humans and livestock has the potential to create novel pathogen strains, highlighted by the influenza pandemic H1N1/09, which was derived from a re-assortment of swine, avian and human influenza A viruses. Here we investigated whether genetic recombination between subspecies of the protozoan parasite, Trypanosoma brucei, from humans and animals can generate new strains of human pathogen, T. b. rhodesiense (Tbr responsible for sleeping sickness (Human African Trypanosomiasis, HAT in East Africa. The trait of human infectivity in Tbr is conferred by a single gene, SRA, which is potentially transferable to the animal pathogen Tbb by sexual reproduction. We tracked the inheritance of SRA in crosses of Tbr and Tbb set up by co-transmitting genetically-engineered fluorescent parental trypanosome lines through tsetse flies. SRA was readily transferred into new genetic backgrounds by sexual reproduction between Tbr and Tbb, thus creating new strains of the human pathogen, Tbr. There was no evidence of diminished growth or transmissibility of hybrid trypanosomes carrying SRA. Although expression of SRA is critical to survival of Tbr in the human host, we show that the gene exists as a single copy in a representative collection of Tbr strains. SRA was found on one homologue of chromosome IV in the majority of Tbr isolates examined, but some Ugandan Tbr had SRA on both homologues. The mobility of SRA by genetic recombination readily explains the observed genetic variability of Tbr in East Africa. We conclude that new strains of the human pathogen Tbr are being generated continuously by recombination with the much larger pool of animal-infective trypanosomes. Such novel recombinants present a risk for future outbreaks of HAT.

  2. Genetic recombination between human and animal parasites creates novel strains of human pathogen.

    Science.gov (United States)

    Gibson, Wendy; Peacock, Lori; Ferris, Vanessa; Fischer, Katrin; Livingstone, Jennifer; Thomas, James; Bailey, Mick

    2015-03-01

    Genetic recombination between pathogens derived from humans and livestock has the potential to create novel pathogen strains, highlighted by the influenza pandemic H1N1/09, which was derived from a re-assortment of swine, avian and human influenza A viruses. Here we investigated whether genetic recombination between subspecies of the protozoan parasite, Trypanosoma brucei, from humans and animals can generate new strains of human pathogen, T. b. rhodesiense (Tbr) responsible for sleeping sickness (Human African Trypanosomiasis, HAT) in East Africa. The trait of human infectivity in Tbr is conferred by a single gene, SRA, which is potentially transferable to the animal pathogen Tbb by sexual reproduction. We tracked the inheritance of SRA in crosses of Tbr and Tbb set up by co-transmitting genetically-engineered fluorescent parental trypanosome lines through tsetse flies. SRA was readily transferred into new genetic backgrounds by sexual reproduction between Tbr and Tbb, thus creating new strains of the human pathogen, Tbr. There was no evidence of diminished growth or transmissibility of hybrid trypanosomes carrying SRA. Although expression of SRA is critical to survival of Tbr in the human host, we show that the gene exists as a single copy in a representative collection of Tbr strains. SRA was found on one homologue of chromosome IV in the majority of Tbr isolates examined, but some Ugandan Tbr had SRA on both homologues. The mobility of SRA by genetic recombination readily explains the observed genetic variability of Tbr in East Africa. We conclude that new strains of the human pathogen Tbr are being generated continuously by recombination with the much larger pool of animal-infective trypanosomes. Such novel recombinants present a risk for future outbreaks of HAT.

  3. Stage at diagnosis and ovarian cancer survival

    DEFF Research Database (Denmark)

    Maringe, Camille; Walters, Sarah; Butler, John

    2012-01-01

    We investigate what role stage at diagnosis bears in international differences in ovarian cancer survival.......We investigate what role stage at diagnosis bears in international differences in ovarian cancer survival....

  4. Life-Cycle Models for Survivable Systems

    National Research Council Canada - National Science Library

    Linger, Richard

    2002-01-01

    .... Current software development life-cycle models are not focused on creating survivable systems, and exhibit shortcomings when the goal is to develop systems with a high degree of assurance of survivability...

  5. Probability of Survival Decision Aid (PSDA)

    National Research Council Canada - National Science Library

    Xu, Xiaojiang; Amin, Mitesh; Santee, William R

    2008-01-01

    A Probability of Survival Decision Aid (PSDA) is developed to predict survival time for hypothermia and dehydration during prolonged exposure at sea in both air and water for a wide range of environmental conditions...

  6. Serpin functions in host-pathogen interactions

    Directory of Open Access Journals (Sweden)

    Jialing Bao

    2018-04-01

    Full Text Available Serpins are a broadly distributed superfamily of protease inhibitors that are present in all kingdoms of life. The acronym, serpin, is derived from their function as potent serine proteases inhibitors. Early studies of serpins focused on their functions in haemostasis since modulating serine proteases activities are essential for coagulation. Additional research has revealed that serpins function in infection and inflammation, by modulating serine and cysteine proteases activities. The aim of this review is to summarize the accumulating findings and current understanding of the functions of serpins in host-pathogen interactions, serving as host defense proteins as well as pathogenic factors. We also discuss the potential crosstalk between host and pathogen serpins. We anticipate that future research will elucidate the therapeutic value of this novel target.

  7. Pathogenicity gene variations within the order Entomophthorales

    DEFF Research Database (Denmark)

    Grell, Morten Nedergaard; Jensen, Annette Bruun; Lange, Lene

    Fungi within the order Entomophthorales (subphylum Entomophthoromycotina) are obligate biotrophic pathogens of arthropods with a remarkable narrow host range. Infection takes place through the cuticle when conidia hit a susceptible host, facilitated by enzymatic and mechanical mechanisms. In the ...... pathogenicity genes within genera Entomophthora and Pandora, using fungal genomic DNA originating from field-collected, infected insect host species of dipteran (flies, mosquitoes) or hemipteran (aphid) origin.......Fungi within the order Entomophthorales (subphylum Entomophthoromycotina) are obligate biotrophic pathogens of arthropods with a remarkable narrow host range. Infection takes place through the cuticle when conidia hit a susceptible host, facilitated by enzymatic and mechanical mechanisms......, conidia are produced and discharged when humidity gets high—usually during night. In an earlier secretome study of field-collected grain aphids (Sitobion avenae) infected with entomophthoralean fungi, a number of pathogenesis-related, secreted enzymes were discovered (Fungal Genetics and Biology 2011, vol...

  8. Threats and opportunities of plant pathogenic bacteria.

    Science.gov (United States)

    Tarkowski, Petr; Vereecke, Danny

    2014-01-01

    Plant pathogenic bacteria can have devastating effects on plant productivity and yield. Nevertheless, because these often soil-dwelling bacteria have evolved to interact with eukaryotes, they generally exhibit a strong adaptivity, a versatile metabolism, and ingenious mechanisms tailored to modify the development of their hosts. Consequently, besides being a threat for agricultural practices, phytopathogens may also represent opportunities for plant production or be useful for specific biotechnological applications. Here, we illustrate this idea by reviewing the pathogenic strategies and the (potential) uses of five very different (hemi)biotrophic plant pathogenic bacteria: Agrobacterium tumefaciens, A. rhizogenes, Rhodococcus fascians, scab-inducing Streptomyces spp., and Pseudomonas syringae. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Histone Acetylation in Fungal Pathogens of Plants

    Directory of Open Access Journals (Sweden)

    Junhyun Jeon

    2014-03-01

    Full Text Available Acetylation of histone lysine residues occurs in different organisms ranging from yeast to plants and mammals for the regulation of diverse cellular processes. With the identification of enzymes that create or reverse this modification, our understanding on histone acetylation has expanded at an amazing pace during the last two decades. In fungal pathogens of plants, however, the importance of such modification has only just begun to be appreciated in the recent years and there is a dearth of information on how histone acetylation is implicated in fungal pathogenesis. This review covers the current status of research related to histone acetylation in plant pathogenic fungi and considers relevant findings in the interaction between fungal pathogens and host plants. We first describe the families of histone acetyltransferases and deacetylases. Then we provide the cases where histone acetylation was investigated in the context of fungal pathogenesis. Finally, future directions and perspectives in epigenetics of fungal pathogenesis are discussed.

  10. Expression Study of Banana Pathogenic Resistance Genes

    Directory of Open Access Journals (Sweden)

    Fenny M. Dwivany

    2016-10-01

    Full Text Available Banana is one of the world's most important trade commodities. However, infection of banana pathogenic fungi (Fusarium oxysporum race 4 is one of the major causes of decreasing production in Indonesia. Genetic engineering has become an alternative way to control this problem by isolating genes that involved in plant defense mechanism against pathogens. Two of the important genes are API5 and ChiI1, each gene encodes apoptosis inhibitory protein and chitinase enzymes. The purpose of this study was to study the expression of API5 and ChiI1 genes as candidate pathogenic resistance genes. The amplified fragments were then cloned, sequenced, and confirmed with in silico studies. Based on sequence analysis, it is showed that partial API5 gene has putative transactivation domain and ChiI1 has 9 chitinase family GH19 protein motifs. Data obtained from this study will contribute in banana genetic improvement.

  11. Peritoneal dialysis peritonitis by anaerobic pathogens: a retrospective case series

    Science.gov (United States)

    2013-01-01

    Background Bacterial infections account for most peritoneal dialysis (PD)-associated peritonitis episodes. However, anaerobic PD peritonitis is extremely rare and intuitively associated with intra-abdominal lesions. In this study, we examined the clinical characteristics of PD patients who developed anaerobic peritonitis. Methods We retrospectively identified all anaerobic PD peritonitis episodes from a prospectively collected PD registry at a single center between 1990 and 2010. Only patients receiving more than 3 months of PD were enrolled. We analyzed clinical features as well as outcomes of anaerobic PD peritonitis patients. Results Among 6 patients, 10 episodes of PD-associated peritonitis were caused by anaerobic pathogens (1.59% of all peritonitis episodes during study the period), in which the cultures from 5 episodes had mixed growth. Bacteroides fragilis was the most common species identified (4 isolates). Only 3 episodes were associated with gastrointestinal lesions, and 4 episodes were related to a break in sterility during exchange procedures. All anaerobic pathogens were susceptible to clindamycin and metronidazole, but penicillin resistance was noted in 4 isolates. Ampicillin/sulbactam resistance was found in 2 isolates. In 5 episodes, a primary response was achieved using the first-generation cephalosporin and ceftazidime or aminoglycoside. In 3 episodes, the first-generation cephalosporin was replaced with aminoglycosides. Tenckhoff catheter removal was necessary in 2 episodes. Only one episode ended with mortality (due to a perforated bowel). Conclusion Anaerobic PD-associated peritonitis might be predominantly caused by contamination, rather than intra-abdominal events. Half of anaerobic PD-associated peritonitis episodes had polymicrobial growth. The overall outcome of anaerobic peritonitis is fair, with a high catheter survival rate. PMID:23705895

  12. IPO survival in a reputational market

    OpenAIRE

    Espenlaub, Susanne; Khurshed, Arif; Mohamed, Abdulkadir

    2012-01-01

    We examine IPO survival in a 'reputational' market, the Alternative Investment Market (AIM), where principle-based regulation pivots on the role of a regulatory agent, the nominated advisor (Nomad) to the IPO company. We find that Nomad reputation has a significant impact on IPO survival. IPOs backed by reputable Nomads 'survive longer (by about two years) than those backed by other Nomads. We also find that survival rates of AIM IPOs are broadly comparable to those of North American IPOs. Wh...

  13. Survival Patterns Among Newcomers To Franchising

    OpenAIRE

    Timothy Bates

    1997-01-01

    This study analyzes survival patterns among franchisee firms and establishments that began operations in 1986 and 1987. Differing methodologies and data bases are utilized to demonstrate that 1) franchises have higher survival rates than independents, and 2) franchises have lower survival rates than independent business formations. Analyses of corporate establishment data generate high franchisee survival rates relative to independents, while analyses of young firm data generate the opposite ...

  14. Photoinactivation of major bacterial pathogens in aquaculture

    Directory of Open Access Journals (Sweden)

    Heyong Jin Roh

    2016-08-01

    Full Text Available Abstract Background Significant increases in the bacterial resistance to various antibiotics have been found in fish farms. Non-antibiotic therapies for infectious diseases in aquaculture are needed. In recent years, light-emitting diode technology has been applied to the inactivation of pathogens, especially those affecting humans. The purpose of this study was to assess the effect of blue light (wavelengths 405 and 465 nm on seven major bacterial pathogens that affect fish and shellfish important in aquaculture. Results We successfully demonstrate inactivation activity of a 405/465-nm LED on selected bacterial pathogens. Although some bacteria were not fully inactivated by the 465-nm light, the 405-nm light had a bactericidal effect against all seven pathogens, indicating that blue light can be effective without the addition of a photosensitizer. Photobacterium damselae, Vibrio anguillarum, and Edwardsiella tarda were the most susceptible to the 405-nm light (36.1, 41.2, and 68.4 J cm−2, respectively, produced one log reduction in the bacterial populations, whereas Streptococcus parauberis was the least susceptible (153.8 J cm−2 per one log reduction. In general, optical density (OD values indicated that higher bacterial densities were associated with lower inactivating efficacy, with the exception of P. damselae and Vibrio harveyi. In conclusion, growth of the bacterial fish and shellfish pathogens evaluated in this study was inactivated by exposure to either the 405- or 465-nm light. In addition, inactivation was dependent on exposure time. Conclusions This study presents that blue LED has potentially alternative therapy for treating fish and shellfish bacterial pathogens. It has great advantages in aspect of eco-friendly treating methods differed from antimicrobial methods.

  15. Differentiation between a pathogenic and a non-pathogenic form of Gyrodactylus salaris using PCR-RFLP

    DEFF Research Database (Denmark)

    Kania, Per Walther; Jørgensen, Thomas Rohde; Buchmann, Kurt

    2007-01-01

    A new method based on PCR-RFLP is presented. It is able to differentiate between the Danish non-pathogenic form of Gyrodactylus salaris and the Norwegian pathogenic form.......A new method based on PCR-RFLP is presented. It is able to differentiate between the Danish non-pathogenic form of Gyrodactylus salaris and the Norwegian pathogenic form....

  16. Starvation-Survival in Haloarchaea.

    Science.gov (United States)

    Winters, Yaicha D; Lowenstein, Tim K; Timofeeff, Michael N

    2015-11-12

    Recent studies claiming to revive ancient microorganisms trapped in fluid inclusions in halite have warranted an investigation of long-term microbial persistence. While starvation-survival is widely reported for bacteria, it is less well known for halophilic archaea-microorganisms likely to be trapped in ancient salt crystals. To better understand microbial survival in fluid inclusions in ancient evaporites, laboratory experiments were designed to simulate growth of halophilic archaea under media-rich conditions, complete nutrient deprivation, and a controlled substrate condition (glycerol-rich) and record their responses. Haloarchaea used for this work included Hbt. salinarum and isolate DV582A-1 (genus Haloterrigena) sub-cultured from 34 kyear Death Valley salt. Hbt. salinarum and DV582A-1 reacted to nutrient limitation with morphological and population changes. Starved populations increased and most cells converted from rods to small cocci within 56 days of nutrient deprivation. The exact timing of starvation adaptations and the physical transformations differed between species, populations of the same species, and cells of the same population. This is the first study to report the timing of starvation strategies for Hbt. salinarum and DV582A-1. The morphological states in these experiments may allow differentiation between cells trapped with adequate nutrients (represented here by early stages in nutrient-rich media) from cells trapped without nutrients (represented here by experimental starvation) in ancient salt. The hypothesis that glycerol, leaked from Dunaliella, provides nutrients for the survival of haloarchaea trapped in fluid inclusions in ancient halite, is also tested. Hbt. salinarum and DV582A-1 were exposed to a mixture of lysed and intact Dunaliella for 56 days. The ability of these organisms to utilize glycerol from Dunaliella cells was assessed by documenting population growth, cell length, and cell morphology. Hbt. salinarum and DV582A-1

  17. Ghrelin as a Survival Hormone.

    Science.gov (United States)

    Mani, Bharath K; Zigman, Jeffrey M

    2017-12-01

    Ghrelin administration induces food intake and body weight gain. Based on these actions, the ghrelin system was initially proposed as an antiobesity target. Subsequent studies using genetic mouse models have raised doubts about the role of the endogenous ghrelin system in mediating body weight homeostasis or obesity. However, this is not to say that the endogenous ghrelin system is not important metabolically or otherwise. Here we review an emerging concept in which the endogenous ghrelin system serves an essential function during extreme nutritional and psychological challenges to defend blood glucose, protect body weight, avoid exaggerated depression, and ultimately allow survival. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Starvation-Survival in Haloarchaea

    Directory of Open Access Journals (Sweden)

    Yaicha D. Winters

    2015-11-01

    Full Text Available Recent studies claiming to revive ancient microorganisms trapped in fluid inclusions in halite have warranted an investigation of long-term microbial persistence. While starvation-survival is widely reported for bacteria, it is less well known for halophilic archaea—microorganisms likely to be trapped in ancient salt crystals. To better understand microbial survival in fluid inclusions in ancient evaporites, laboratory experiments were designed to simulate growth of halophilic archaea under media-rich conditions, complete nutrient deprivation, and a controlled substrate condition (glycerol-rich and record their responses. Haloarchaea used for this work included Hbt. salinarum and isolate DV582A-1 (genus Haloterrigena sub-cultured from 34 kyear Death Valley salt. Hbt. salinarum and DV582A-1 reacted to nutrient limitation with morphological and population changes. Starved populations increased and most cells converted from rods to small cocci within 56 days of nutrient deprivation. The exact timing of starvation adaptations and the physical transformations differed between species, populations of the same species, and cells of the same population. This is the first study to report the timing of starvation strategies for Hbt. salinarum and DV582A-1. The morphological states in these experiments may allow differentiation between cells trapped with adequate nutrients (represented here by early stages in nutrient-rich media from cells trapped without nutrients (represented here by experimental starvation in ancient salt. The hypothesis that glycerol, leaked from Dunaliella, provides nutrients for the survival of haloarchaea trapped in fluid inclusions in ancient halite, is also tested. Hbt. salinarum and DV582A-1 were exposed to a mixture of lysed and intact Dunaliella for 56 days. The ability of these organisms to utilize glycerol from Dunaliella cells was assessed by documenting population growth, cell length, and cell morphology. Hbt. salinarum

  19. Evasion Mechanisms Used by Pathogens to Escape the Lectin Complement Pathway.

    Science.gov (United States)

    Rosbjerg, Anne; Genster, Ninette; Pilely, Katrine; Garred, Peter

    2017-01-01

    The complement system is a crucial defensive network that protects the host against invading pathogens. It is part of the innate immune system and can be initiated via three pathways: the lectin, classical and alternative activation pathway. Overall the network compiles a group of recognition molecules that bind specific patterns on microbial surfaces, a group of associated proteases that initiates the complement cascade, and a group of proteins that interact in proteolytic complexes or the terminal pore-forming complex. In addition, various regulatory proteins are important for controlling the level of activity. The result is a pro-inflammatory response meant to combat foreign microbes. Microbial elimination is, however, not a straight forward procedure; pathogens have adapted to their environment by evolving a collection of evasion mechanisms that circumvent the human complement system. Complement evasion strategies features different ways of exploiting human complement proteins and moreover features different pathogen-derived proteins that interfere with the normal processes. Accumulated, these mechanisms target all three complement activation pathways as well as the final common part of the cascade. This review will cover the currently known lectin pathway evasion mechanisms and give examples of pathogens that operate these to increase their chance of invasion, survival and dissemination.

  20. Fate of pathogens in a simulated bioreduction system for livestock carcasses

    International Nuclear Information System (INIS)

    Gwyther, Ceri L.; Jones, David L.; Golyshin, Peter N.; Edwards-Jones, Gareth; Williams, A. Prysor

    2012-01-01

    Highlights: ► Bioreduction is a novel on-farm storage option for livestock carcasses. ► Legislation demands that pathogens are contained and do not proliferate during carcass storage. ► We examined the survival of key pathogens in lab-scale bioreduction vessels. ► Pathogen numbers reduced in the resulting liquor waste and bioaerosols. ► The results indicate that bioreduction should be validated for industry use. - Abstract: The EU Animal By-Products Regulations generated the need for novel methods of storage and disposal of dead livestock. Bioreduction prior to rendering or incineration has been proposed as a practical and potentially cost-effective method; however, its biosecurity characteristics need to be elucidated. To address this, Salmonella enterica (serovars Senftenberg and Poona), Enterococcus faecalis, Campylobacter jejuni, Campylobacter coli and a lux-marked strain of Escherichia coli O157 were inoculated into laboratory-scale bioreduction vessels containing sheep carcass constituents. Numbers of all pathogens and the metabolic activity of E. coli O157 decreased significantly within the liquor waste over time, and only E. faecalis remained detectable after 3 months. Only very low numbers of Salmonella spp. and E. faecalis were detected in bioaerosols, and only at initial stages of the trial. These results further indicate that bioreduction represents a suitable method of storing and reducing the volume of livestock carcasses prior to ultimate disposal.

  1. Methods for air cleaning and protection of building occupants from airborne pathogens

    Energy Technology Data Exchange (ETDEWEB)

    Bolashikov, Z.D.; Melikov, A.K. [International Centre for Indoor Environment and Energy, Department of Civil Engineering, Technical University of Denmark, Nils Koppels Alle, building 402, 2800 Lyngby (Denmark)

    2009-07-15

    This article aims to draw the attention of the scientific community towards the elevated risks of airborne transmission of diseases and the associated risks of epidemics or pandemics. The complexity of the problem and the need for multidisciplinary research is highlighted. The airborne route of transmission, i.e. the generation of pathogen laden droplets originating in the respiratory tract of an infected individual, the survivability of the pathogens, their dispersal indoors and their transfer to a healthy person are reviewed. The advantages and the drawbacks of air dilution, filtration, ultraviolet germicidal irradiation (UVGI), photocatalytic oxidation (PCO), plasmacluster ions and other technologies for air disinfection and purification from pathogens are analyzed with respect to currently used air distribution principles. The importance of indoor air characteristics, such as temperature, relative humidity and velocity for the efficiency of each method is analyzed, taking into consideration the nature of the pathogens themselves. The applicability of the cleaning methods to the different types of total volume air distribution used at present indoors, i.e. mixing, displacement and underfloor ventilation, as well as advanced air distribution techniques (such as personalized ventilation) is discussed. (author)

  2. DNA mutations mediate microevolution between host-adapted forms of the pathogenic fungus Cryptococcus neoformans.

    Directory of Open Access Journals (Sweden)

    Denise A Magditch

    Full Text Available The disease cryptococcosis, caused by the fungus Cryptococcus neoformans, is acquired directly from environmental exposure rather than transmitted person-to-person. One explanation for the pathogenicity of this species is that interactions with environmental predators select for virulence. However, co-incubation of C. neoformans with amoeba can cause a "switch" from the normal yeast morphology to a pseudohyphal form, enabling fungi to survive exposure to amoeba, yet conversely reducing virulence in mammalian models of cryptococcosis. Like other human pathogenic fungi, C. neoformans is capable of microevolutionary changes that influence the biology of the organism and outcome of the host-pathogen interaction. A yeast-pseudohyphal phenotypic switch also happens under in vitro conditions. Here, we demonstrate that this morphological switch, rather than being under epigenetic control, is controlled by DNA mutation since all pseudohyphal strains bear mutations within genes encoding components of the RAM pathway. High rates of isolation of pseudohyphal strains can be explained by the physical size of RAM pathway genes and a hypermutator phenotype of the strain used in phenotypic switching studies. Reversion to wild type yeast morphology in vitro or within a mammalian host can occur through different mechanisms, with one being counter-acting mutations. Infection of mice with RAM mutants reveals several outcomes: clearance of the infection, asymptomatic maintenance of the strains, or reversion to wild type forms and progression of disease. These findings demonstrate a key role of mutation events in microevolution to modulate the ability of a fungal pathogen to cause disease.

  3. Bacteria between protists and phages: from antipredation strategies to the evolution of pathogenicity.

    Science.gov (United States)

    Brüssow, Harald

    2007-08-01

    Bacteriophages and protists are major causes of bacterial mortality. Genomics suggests that phages evolved well before eukaryotic protists. Bacteria were thus initially only confronted with phage predators. When protists evolved, bacteria were caught between two types of predators. One successful antigrazing strategy of bacteria was the elaboration of toxins that would kill the grazer. The released cell content would feed bystander bacteria. I suggest here that, to fight grazing protists, bacteria teamed up with those phage predators that concluded at least a temporary truce with them in the form of lysogeny. Lysogeny was perhaps initially a resource management strategy of phages that could not maintain infection chains. Subsequently, lysogeny might have evolved into a bacterium-prophage coalition attacking protists, which became a food source for them. When protists evolved into multicellular animals, the lysogenic bacteria tracked their evolving food source. This hypothesis could explain why a frequent scheme of bacterial pathogenicity is the survival in phagocytes, why a significant fraction of bacterial pathogens have prophage-encoded virulence genes, and why some virulence factors of animal pathogens are active against unicellular eukaryotes. Bacterial pathogenicity might thus be one playing option of the stone-scissor-paper game played between phages-bacteria-protists, with humans getting into the crossfire.

  4. A teleost CD46 is involved in the regulation of complement activation and pathogen infection.

    Science.gov (United States)

    Li, Mo-Fei; Sui, Zhi-Hai; Sun, Li

    2017-11-03

    In mammals, CD46 is involved in the inactivation of complement by factor I (FI). In teleost, study on the function of CD46 is very limited. In this study, we examined the immunological property of a CD46 molecule (CsCD46) from tongue sole, a teleost species with important economic value. We found that recombinant CsCD46 (rCsCD46) interacted with FI and inhibited complement activation in an FI-dependent manner. rCsCD46 also interacted with bacterial pathogens via a different mechanism to that responsible for the FI interaction, involving different rCsCD46 sites. Cellular study showed that CsCD46 was expressed on peripheral blood leukocytes (PBL) and protected the cells against the killing effect of complement. When the CsCD46 on PBL was blocked by antibody before incubation of the cells with bacterial pathogens, cellular infection was significantly reduced. Consistently, when tongue sole were infected with bacterial pathogens in the presence of rCsCD46, tissue dissemination and survival of the pathogens were significantly inhibited. These results provide the first evidence to indicate that CD46 in teleosts negatively regulates complement activation via FI and protects host cells from complement-induced damage, and that CD46 is required for optimal bacterial infection probably by serving as a receptor for the bacteria.

  5. Molecular techniques for characterisation of pathogens

    DEFF Research Database (Denmark)

    Kampmann, Marie-Louise

    Pathogens have always had a major interest to humans due to their central role in sickness and death. Influenza A annually kills at least 250,000 humans, and has been the cause of millions of further deaths during pandemic years in the past. Plague (Yersinia pestis) has been the cause of the Black...... capture for the detection of Y. pestis in samples from the Justinian plague (600 AD) as an attempt to detect this pathogen as a cause of death in the victims....

  6. Whole-genome sequencing of veterinary pathogens

    DEFF Research Database (Denmark)

    Ronco, Troels

    -electrophoresis and single-locus sequencing has been widely used to characterize such types of veterinary pathogens. However, DNA sequencing techniques have become fast and cost effective in recent years and whole-genome sequencing data provide a much higher discriminative power and reproducibility than any...... genetic background. This indicates that dairy cows can be natural carriers of S. aureus subtypes that in certain cases lead to CM. A group of isolates that mostly belonged to ST151 carried three pathogenicity islands that were primarily found in this group. The prevalence of resistance genes was generally...

  7. Effect of APOE ε4 allele on survival and fertility in an adverse environment.

    Directory of Open Access Journals (Sweden)

    Eric van Exel

    Full Text Available The apolipoprotein-ε4 allele (APOE-ε4 is strongly associated with detrimental outcomes in affluent populations including atherosclerotic disease, Alzheimer's disease, and reduced lifespan. Despite these detrimental outcomes, population frequencies of APOE-ε4 are high. We hypothesize that the high frequency of APOE-ε4 was maintained because of beneficial effects during evolution when infectious pathogens were more prevalent and a major cause of mortality. We examined a rural Ghanaian population with a high pathogen exposure for selective advantages of APOE-ε4, to survival and or fertility.This rural Ghanaian population (n = 4311 has high levels of mortality from widespread infectious diseases which are the main cause of death. We examined whether APOE-ε4 was associated with survival (total follow-up time was 30,262 years and fertility after stratifying by exposure to high or low pathogen levels. Households drawing water from open wells and rivers were classified as exposed to high pathogen levels while low pathogen exposure was classified as those drawing water from borehole wells. We found a non-significant, but positive survival benefit, i.e. the hazard ratio per APOE-ε4 allele was 0.80 (95% confidence interval: 0.69 to 1.05, adjusted for sex, tribe, and socioeconomic status. Among women aged 40 years and older (n = 842, APOE-ε4 was not associated with the lifetime number of children. However, APOE-ε4 was associated with higher fertility in women exposed to high pathogen levels. Compared with women not carrying an APOE-ε4 allele, those carrying one APOE-ε4 allele had on average one more child and those carrying two APOE-ε4 alleles had 3.5 more children (p = 0.018.Contrary to affluent modern-day populations, APOE-ε4 did not carry a survival disadvantage in this rural Ghanaian population. Moreover, APOE-ε4 promotes fertility in highly infectious environments. Our findings suggest that APOE-ε4 may be considered as evolutionarily

  8. Effect of APOE ε4 allele on survival and fertility in an adverse environment.

    Science.gov (United States)

    van Exel, Eric; Koopman, Jacob J E; Bodegom, David van; Meij, Johannes J; Knijff, Peter de; Ziem, Juventus B; Finch, Caleb E; Westendorp, Rudi G J

    2017-01-01

    The apolipoprotein-ε4 allele (APOE-ε4) is strongly associated with detrimental outcomes in affluent populations including atherosclerotic disease, Alzheimer's disease, and reduced lifespan. Despite these detrimental outcomes, population frequencies of APOE-ε4 are high. We hypothesize that the high frequency of APOE-ε4 was maintained because of beneficial effects during evolution when infectious pathogens were more prevalent and a major cause of mortality. We examined a rural Ghanaian population with a high pathogen exposure for selective advantages of APOE-ε4, to survival and or fertility. This rural Ghanaian population (n = 4311) has high levels of mortality from widespread infectious diseases which are the main cause of death. We examined whether APOE-ε4 was associated with survival (total follow-up time was 30,262 years) and fertility after stratifying by exposure to high or low pathogen levels. Households drawing water from open wells and rivers were classified as exposed to high pathogen levels while low pathogen exposure was classified as those drawing water from borehole wells. We found a non-significant, but positive survival benefit, i.e. the hazard ratio per APOE-ε4 allele was 0.80 (95% confidence interval: 0.69 to 1.05), adjusted for sex, tribe, and socioeconomic status. Among women aged 40 years and older (n = 842), APOE-ε4 was not associated with the lifetime number of children. However, APOE-ε4 was associated with higher fertility in women exposed to high pathogen levels. Compared with women not carrying an APOE-ε4 allele, those carrying one APOE-ε4 allele had on average one more child and those carrying two APOE-ε4 alleles had 3.5 more children (p = 0.018). Contrary to affluent modern-day populations, APOE-ε4 did not carry a survival disadvantage in this rural Ghanaian population. Moreover, APOE-ε4 promotes fertility in highly infectious environments. Our findings suggest that APOE-ε4 may be considered as evolutionarily adaptive. Its

  9. Survival of adult martens in Northern Wisconsin

    Science.gov (United States)

    Nicholas P. McCann; Patrick A. Zollner; Jonathan H. Gilbert

    2010-01-01

    Low adult marten (Martes americana) survival may be one factor limiting their population growth >30 yr after their reintroduction in Wisconsin, USA. We estimated annual adult marten survival at 0.81 in northern Wisconsin, with lower survival during winter (0.87) than summer-fall (1.00). Fisher (Martes pennanti) and raptor kills...

  10. 46 CFR 199.201 - Survival craft.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Survival craft. 199.201 Section 199.201 Shipping COAST... craft. (a) Each survival craft must be approved and equipped as follows: (1) Each lifeboat must be... addition to the survival craft required in paragraph (b)(1) of this section, additional liferafts must be...

  11. 46 CFR 199.261 - Survival craft.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Survival craft. 199.261 Section 199.261 Shipping COAST... SYSTEMS FOR CERTAIN INSPECTED VESSELS Additional Requirements for Cargo Vessels § 199.261 Survival craft. (a) Each survival craft must be approved and equipped as follows: (1) Each lifeboat must be a totally...

  12. 46 CFR 28.120 - Survival craft.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Survival craft. 28.120 Section 28.120 Shipping COAST... VESSELS Requirements for All Vessels § 28.120 Survival craft. (a) Except as provided in paragraphs (b) through (h) of this section and 28.305, each vessel must carry the survival craft specified in Table 28...

  13. 46 CFR 133.105 - Survival craft.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Survival craft. 133.105 Section 133.105 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS LIFESAVING SYSTEMS Requirements for All OSVs § 133.105 Survival craft. (a) Each survival craft must be approved and equipped as...

  14. Heme as a danger molecule in pathogen recognition.

    Science.gov (United States)

    Wegiel, Barbara; Hauser, Carl J; Otterbein, Leo E

    2015-12-01

    Appropriate control of redox mechanisms are critical for and effective innate immune response, which employs multiple cell types, receptors and molecules that recognize danger signals when they reach the host. Recognition of pathogen-associated pattern molecules (PAMPs) is a fundamental host survival mechanism for efficient elimination of invading pathogens and resolution of the infection and inflammation. In addition to PAMPs, eukaryotic cells contain a plethora of intracellular molecules that are normally secured within the confines of the plasma membrane, but if liberated and encountered in the extracellular milieu can provoke rapid cell activation. These are known as Alarmins or Danger-Associated Molecular Patterns (DAMPs) and can be released actively by cells or passively as a result of sterile cellular injury after trauma, ischemia, or toxin-induced cell rupture. Both PAMPs and DAMPs are recognized by a series of cognate receptors that increase the generation of free radicals and activate specific signaling pathways that result in regulation of a variety of stress response, redox sensitive genes. Multiple mediators released, as cells die include, but are not limited to ATP, hydrogen peroxide, heme, formyl peptides, DNA or mitochondria provide the second signal to amplify immune responses. In this review, we will focus on how sterile and infective stimuli activate the stress response gene heme oxygenase-1 (Hmox1, HO-1), a master gene critical to an appropriate host response that is now recognized as one with enormous therapeutic potential. HO-1 gene expression is regulated in large part by redox-sensitive proteins including but not limited to nrf2. Both PAMPs and DAMPs increase the activation of nrf2 and HO-1. Heme is a powerful pro-oxidant and as such should be qualified as a DAMP. With its degradation by HO-1a molecule of carbon monoxide (CO) is generated that in turn serves as a bioactive signaling molecule. PAMPs such as bacterial endotoxin activate HO-1

  15. The urban phenomenon and re-spatialization of the complex pathogens

    Directory of Open Access Journals (Sweden)

    Jorge A. Pickenhayn

    2008-06-01

    More than half of a century has passed since the popularization of the concept of pathogen complex. During this time, the world urban population has been multiplied by five, compared to the rural population. The environmental changes led to ecological modifications in these dynamic systems, perceptible in the agents and vectors of the transmitted pathologies, which adopted new strategies of survival. A case study in the city of San Juan, Argentina, where the pathogen complex of the Chagas’ Disease registers transformations, is presented. Its vector, Triatoma infestans, gradually carries its populations from the surrounding rural environments to the city. To do this, it profits from an inter-specific relationship with doves (Columba livia, acting on them as parasite, and takes advantage of their mobility.

  16. [Chlamydia trachomatis proteasome protein as one of the significant pathogenicity factors of exciter].

    Science.gov (United States)

    Davydov, D Iu; Zigangirova, N A

    2014-01-01

    Sex-related infections are a global problem. Such infections may lead to acute or chronic diseases. Chlamydia trachomatis is a dangerous and widespread pathogenicity factor that is not sensitive to conventional drugs and has no obvious symptoms. Protein CPAF is leading factor of pathogenesis. This protein inhibits the signaling pathways of host cell and supports long survival of the pathogen in the host cell. The goal of this work was to review general properties of the proteasome Chlamydia protein CPAF, its functions, and role in pathology. The role of protein CPAF in the anti-chlamydia immune reaction is discussed. The prospects of the development of promising anti-chlamydia vaccine, as well as new effective anti-chlamydia drugs are also discussed.

  17. Breaking into the epithelial apical-junctional complex--news from pathogen hackers.

    Science.gov (United States)

    Vogelmann, Roger; Amieva, Manuel R; Falkow, Stanley; Nelson, W James

    2004-02-01

    The epithelial apical-junctional complex is a key regulator of cellular functions. In addition, it is an important target for microbial pathogens that manipulate the cell to survive, proliferate and sometimes persist within a host. Out of a myriad of potential molecular targets, some bacterial and viral pathogens have selected a subset of protein targets at the apical-junctional complex of epithelial cells. Studying how microbes use these targets also teaches us about the inherent physiological properties of host molecules in the context of normal junctional structure and function. Thus, we have learned that three recently uncovered components of the apical-junctional complex of the Ig superfamily--junctional adhesion molecule, Nectin and the coxsackievirus and adenovirus receptor--are important regulators of junction structure and function and represent critical targets of microbial virulence gene products.

  18. Breaking into the epithelial apical–junctional complex — news from pathogen hackers

    Science.gov (United States)

    Vogelmann, Roger; Amieva, Manuel R; Falkow, Stanley; Nelson, W James

    2012-01-01

    The epithelial apical–junctional complex is a key regulator of cellular functions. In addition, it is an important target for microbial pathogens that manipulate the cell to survive, proliferate and sometimes persist within a host. Out of a myriad of potential molecular targets, some bacterial and viral pathogens have selected a subset of protein targets at the apical–junctional complex of epithelial cells. Studying how microbes use these targets also teaches us about the inherent physiological properties of host molecules in the context of normal junctional structure and function. Thus, we have learned that three recently uncovered components of the apical–junctional complex of the Ig superfamily — junctional adhesion molecule, Nectin and the coxsackievirus and adenovirus receptor — are important regulators of junction structure and function and represent critical targets of microbial virulence gene products. PMID:15037310

  19. The application of bioflocs technology to protect brine shrimp (Artemia franciscana) from pathogenic Vibrio harveyi.

    Science.gov (United States)

    Crab, R; Lambert, A; Defoirdt, T; Bossier, P; Verstraete, W

    2010-11-01

    To study the potential biocontrol activity of bioflocs technology. Glycerol-grown bioflocs were investigated for their antimicrobial and antipathogenic properties against the opportunistic pathogen Vibrio harveyi. The bioflocs did not produce growth-inhibitory substances. However, bioflocs and biofloc supernatants decreased quorum sensing-regulated bioluminescence of V. harveyi. This suggested that the bioflocs had biocontrol activity against this pathogen because quorum sensing regulates virulence of vibrios towards different hosts. Interestingly, the addition of live bioflocs significantly increased the survival of gnotobiotic brine shrimp (Artemia franciscana) larvae challenged to V. harveyi. Bioflocs grown on glycerol as carbon source inhibit quorum sensing-regulated bioluminescence in V. harveyi and protect brine shrimp larvae from vibriosis. The results presented in this study indicate that in addition to water quality control and in situ feed production, bioflocs technology could help in controlling bacterial infections within the aquaculture pond. © 2010 The Authors. Journal of Applied Microbiology © 2010 The Society for Applied Microbiology.

  20. Improving fish survival through turbines

    International Nuclear Information System (INIS)

    Ferguson, J.W.

    1993-01-01

    Much of what is known about fish passage through hydroturbines has been developed by studying migratory species of fish passing through large Kaplan turbine units. A review of the literature on previous fish passage research presented in the accompanying story illustrates that studies have focused on determining mortality levels, rather than identifying the causal mechanism involved. There is a need for understanding how turbine designs could be altered to improve fish passage conditions, how to retrofit existing units, and how proposed hydro plant operational changes may affect fish survival. The US Army Corps of Engineers has developed a research program to define biologically based engineering criteria for improving fish passage conditions. Turbine designs incorporating these criteria can be evaluated for their effects on fish survival, engineering issues, costs, and power production. The research program has the following objectives: To gain a thorough knowledge of the mechanisms of fish mortality; To define the biological sensitivities of key fish species to these mechanisms of mortality; To develop new turbine design criteria to reduce fish mortality; To construct prototype turbine designs, and to test these designs for fish passage, hydro-mechanical operation, and power production; and To identify construction and power costs associated with new turbine designs

  1. Survival strategies in arctic ungulates

    Directory of Open Access Journals (Sweden)

    N. J. C. Tyler

    1990-09-01

    Full Text Available Arctic ungulates usually neither freeze nor starve to death despite the rigours of winter. Physiological adaptations enable them to survive and reproduce despite long periods of intense cold and potential undernutrition. Heat conservation is achieved by excellent insulation combined with nasal heat exchange. Seasonal variation in fasting metabolic rate has been reported in several temperate and sub-arctic species of ungulates and seems to occur in muskoxen. Surprisingly, there is no evidence for this in reindeer. Both reindeer and caribou normally maintain low levels of locomotor activity in winter. Light foot loads are important for reducing energy expenditure while walking over snow. The significance and control of selective cooling of the brain during hard exercise (e.g. escape from predators is discussed. Like other cervids, reindeer and caribou display a pronounced seasonal cycle of appetite and growth which seems to have an intrinsic basis. This has two consequences. First, the animals evidently survive perfectly well despite enduring negative energy balance for long periods. Second, loss of weight in winter is not necessarily evidence of undernutrition. The main role of fat reserves, especially in males, may be to enhance reproductive success. The principal role of fat reserves in winter appears to be to provide a supplement to, rather than a substitute for, poor quality winter forage. Fat also provides an insurance against death during periods of acute starvation.

  2. Survival study of enterotoxigenic Escherichia colistrain in seawater and wastewater microcosms.

    Science.gov (United States)

    Boukef Ben Omrane, I; El Bour, M; Mejri, S; Mraouna, R; Got, P; Troussellier, M; Boudabous, A

    2011-01-01

    In order to survey osmotic and oligotrophic stress consequence on pathogenic enterobacteria discharged in marine areas, we examined enterotoxigenic Escherichia coli (ETEC) and a reference (Ecoli O126:B16) strains during their survival (47 days) in wastewater microcosms, submerged in natural seawater and maintained in laboratory conditions. The results revealed that the survival time for the two strains was prolonged when bacterial cells were previously incubated in wastewater, with less cellular membrane damage. In addition, the wild clinical E. coli strain showed a better survival capacity than the reference E. coli strain one. For both, we noted some modifications in biochemical profiles relatively to the initial state, notably when they were previously incubated in wastewater microcosm.

  3. Seed bank survival of an invasive species, but not of two native species, declines with invasion.

    Science.gov (United States)

    Orrock, John L; Christopher, Cory C; Dutra, Humberto P

    2012-04-01

    Soil-borne seed pathogens may play an important role in either hindering or facilitating the spread of invasive exotic plants. We examined whether the invasive shrub Lonicera maackii (Caprifoliaceae) affected fungi-mediated mortality of conspecific and native shrub seeds in a deciduous forest in eastern Missouri. Using a combination of L. maackii removal and fungicide treatments, we found no effect of L. maackii invasion on seed viability of the native Symphoricarpos orbiculatus (Caprifoliaceae) or Cornus drummondii (Cornaceae). In contrast, fungi were significant agents of L. maackii seed mortality in invaded habitats. Losses of L. maackii to soil fungi were also significant in invaded habitats where L. maackii had been removed, although the magnitude of the effect of fungi was lower, suggesting that changes in soil chemistry or microhabitat caused by L. maackii were responsible for affecting fungal seed pathogens. Our work suggests that apparent competition via soil pathogens is not an important factor contributing to impacts of L. maackii on native shrubs. Rather, we found that fungal seed pathogens have density-dependent effects on L. maackii seed survival. Therefore, while fungal pathogens may provide little biotic resistance to early invasion by L. maackii, our study illustrates that more work is needed to understand how changes in fungal pathogens during the course of an invasion contribute to the potential for restoration of invaded systems. More generally, our study suggests that increased rates of fungal pathogen attack may be realized by invasive plants, such as L. maackii, that change the chemical or physical environment of the habitats they invade.

  4. Survival of Mycobacterium avium in drinking water biofilms as affected by water flow velocity, availability of phosphorus, and temperature.

    Science.gov (United States)

    Torvinen, Eila; Lehtola, Markku J; Martikainen, Pertti J; Miettinen, Ilkka T

    2007-10-01

    Mycobacterium avium is a potential pathogen occurring in drinking water systems. It is a slowly growing bacterium producing a thick cell wall containing mycolic acids, and it is known to resist chlorine better than many other microbes. Several studies have shown that pathogenic bacteria survive better in biofilms than in water. By using Propella biofilm reactors, we studied how factors generally influencing the growth of biofilms (flow rate, phosphorus concentration, and temperature) influence the survival of M. avium in drinking water biofilms. The growth of biofilms was followed by culture and DAPI (4',6'-diamidino-2-phenylindole) staining, and concentrations of M. avium were determined by culture and fluorescence in situ hybridization methods. The spiked M. avium survived in biofilms for the 4-week study period without a dramatic decline in concentration. The addition of phosphorus (10 microg/liter) increased the number of heterotrophic bacteria in biofilms but decreased the culturability of M. avium. The reason for this result is probably that phosphorus increased competition with other microbes. An increase in flow velocity had no effect on the survival of M. avium, although it increased the growth of biofilms. A higher temperature (20 degrees C versus 7 degrees C) increased both the number of heterotrophic bacteria and the survival of M. avium in biofilms. In conclusion, the results show that in terms of affecting the survival of slowly growing M. avium in biofilms, temperature is a more important factor than the availability of nutrients like phosphorus.

  5. Parasitic infection improves survival from septic peritonitis by enhancing mast cell responses to bacteria in mice.

    Directory of Open Access Journals (Sweden)

    Rachel E Sutherland

    Full Text Available Mammals are serially infected with a variety of microorganisms, including bacteria and parasites. Each infection reprograms the immune system's responses to re-exposure and potentially alters responses to first-time infection by different microorganisms. To examine whether infection with a metazoan parasite modulates host responses to subsequent bacterial infection, mice were infected with the hookworm-like intestinal nematode Nippostrongylus brasiliensis, followed in 2-4 weeks by peritoneal injection of the pathogenic bacterium Klebsiella pneumoniae. Survival from Klebsiella peritonitis two weeks after parasite infection was better in Nippostrongylus-infected animals than in unparasitized mice, with Nippostrongylus-infected mice having fewer peritoneal bacteria, more neutrophils, and higher levels of protective interleukin 6. The improved survival of Nippostrongylus-infected mice depends on IL-4 because the survival benefit is lost in mice lacking IL-4. Because mast cells protect mice from Klebsiella peritonitis, we examined responses in mast cell-deficient Kit(W-sh/Kit(W-sh mice, in which parasitosis failed to improve survival from Klebsiella peritonitis. However, adoptive transfer of cultured mast cells to Kit(W-sh/Kit(W-sh mice restored survival benefits of parasitosis. These results show that recent infection with Nippostrongylus brasiliensis protects mice from Klebsiella peritonitis by modulating mast cell contributions to host defense, and suggest more generally that parasitosis can yield survival advantages to a bacterially infected host.

  6. The Tick Microbiome: Why Non-pathogenic Microorganisms Matter in Tick Biology and Pathogen Transmission

    Directory of Open Access Journals (Sweden)

    Sarah I. Bonnet

    2017-06-01

    Full Text Available Ticks are among the most important vectors of pathogens affecting humans and other animals worldwide. They do not only carry pathogens however, as a diverse group of commensal and symbiotic microorganisms are also present in ticks. Unlike pathogens, their biology and their effect on ticks remain largely unexplored, and are in fact often neglected. Nonetheless, they can confer multiple detrimental, neutral, or beneficial effects to their tick hosts, and can play various roles in fitness, nutritional adaptation, development, reproduction, defense against environmental stress, and immunity. Non-pathogenic microorganisms may also play a role in driving transmission of tick-borne pathogens (TBP, with many potential implications for both human and animal health. In addition, the genetic proximity of some pathogens to mutualistic symbionts hosted by ticks is evident when studying phylogenies of several bacterial genera. The best examples are found within members of the Rickettsia, Francisella, and Coxiella genera: while in medical and veterinary research these bacteria are traditionally recognized as highly virulent vertebrate pathogens, it is now clear to evolutionary ecologists that many (if not most Coxiella, Francisella, and Rickettsia bacteria are actually non-pathogenic microorganisms exhibiting alternative lifestyles as mutualistic ticks symbionts. Consequently, ticks represent a compelling yet challenging system in which to study microbiomes and microbial interactions, and to investigate the composition, functional, and ecological implications of bacterial communities. Ultimately, deciphering the relationships between tick microorganisms as well as tick symbiont interactions will garner invaluable information, which may aid in the future development of arthropod pest and vector-borne pathogen transmission control strategies.

  7. Pathogenicity of Genetically Similar, H5N1 Highly Pathogenic Avian Influenza Virus Strains in Chicken and the Differences in Sensitivity among Different Chicken Breeds

    Science.gov (United States)

    Matsuu, Aya; Kobayashi, Tomoko; Patchimasiri, Tuangthong; Shiina, Takashi; Suzuki, Shingo; Chaichoune, Kridsada; Ratanakorn, Parntep; Hiromoto, Yasuaki; Abe, Haruka; Parchariyanon, Sujira; Saito, Takehiko

    2016-01-01

    Differences in the pathogenicity of genetically closely related H5N1 highly pathogenic avian influenza viruses (HPAIVs) were evaluated in White Leghorn chickens. These viruses varied in the clinical symptoms they induced, including lethality, virus shedding, and replication in host tissues. A comparison of the host responses in the lung, brain, and spleen suggested that the differences in viral replication efficiency were related to the host cytokine response at the early phase of infection, especially variations in the proinflammatory cytokine IL-6. Based on these findings, we inoculated the virus that showed the mildest pathogenicity among the five tested, A/pigeon/Thailand/VSMU-7-NPT/2004, into four breeds of Thai indigenous chicken, Phadu-Hung-Dang (PHD), Chee, Dang, and Luang-Hung-Khao (LHK), to explore effects of genetic background on host response. Among these breeds, Chee, Dang, and LHK showed significantly longer survival times than White Leghorns. Virus shedding from dead Thai indigenous chickens was significantly lower than that from White Leghorns. Although polymorphisms were observed in the Mx and MHC class I genes, there was no significant association between the polymorphisms in these loci and resistance to HPAIV. PMID:27078641

  8. The Role of Pathogenic Autoantibodies in Autoimmunity

    Directory of Open Access Journals (Sweden)

    Merrill J. Rowley

    2015-11-01

    Full Text Available The serological presence of autoantibodies is diagnostic of autoimmunity, and these autoantibodies may be present for many years before the presentation of autoimmune disease (AID. Although a pathogenic role has been demonstrated for various autoantibodies reactive with cell surface and extracellular autoantigens, studies using monoclonal antibodies (mAb show not all antibodies in the polyclonal response are pathogenic. Differences depend on Fab-mediated diversity in epitope specificity, Fc-mediated effects based on immunoglobulin (Ig class and subclass, activation of complement, and the milieu in which the reaction occurs. These autoantibodies often occur in organ-specific AID and this review illustrates their pathogenic and highly specific effects. The role of autoantibodies associated with intracellular antigens is less clear. In vitro they may inhibit or adversely affect well-defined intracellular biochemical pathways, yet, in vivo they are separated from their autoantigens by multiple cellular barriers. Recent evidence that Ig can traverse cell membranes, interact with intracellular proteins, and induce apoptosis has provided new evidence for a pathogenic role for such autoantibodies. An understanding of how autoantibodies behave in the polyclonal response and their role in pathogenesis of AID may help identify populations of culprit B-cells and selection of treatments that suppress or eliminate them.

  9. Host-pathogen interactions in typhoid fever

    NARCIS (Netherlands)

    de Jong, H.K.

    2015-01-01

    This thesis focuses on host-pathogen interactions in Salmonella Typhi and Burkholderia pseudomallei infections and explores the interplay between these bacteria and the innate immune system. Typhoid fever is one of the most common causes of bacterial infection in low-income countries. With adequate

  10. Current situation on highly pathogenic avian influenza

    Science.gov (United States)

    Avian influenza is one of the most important diseases affecting the poultry industry worldwide. Avian influenza viruses can cause a range of clinical disease in poultry. Viruses that cause severe disease and mortality are referred to as highly pathogenic avian influenza (HPAI) viruses. The Asian ...

  11. RNAi suppressors encoded by pathogenic human viruses

    NARCIS (Netherlands)

    de Vries, Walter; Berkhout, Ben

    2008-01-01

    RNA silencing or RNAi interference (RNAi) serves as an innate antiviral mechanism in plants, fungi and animals. Human viruses, like plant viruses, encode suppressor proteins or RNAs that block or modulate the RNAi pathway. This review summarizes the mechanisms by which pathogenic human viruses

  12. Low-Incidence, High-Consequence Pathogens

    Centers for Disease Control (CDC) Podcasts

    2014-02-21

    Dr. Stephan Monroe, a deputy director at CDC, discusses the impact of low-incidence, high-consequence pathogens globally.  Created: 2/21/2014 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 2/26/2014.

  13. Rapid methods: the detection of foodborne pathogens

    NARCIS (Netherlands)

    Beumer, R.R.; Hazeleger, W.C.

    2009-01-01

    Although bacteria are the first type of microorganisms that come to mind when discussing microbial food safety, they are by no means the only pathogenic foodborne microorganisms. Mycotoxin producing moulds, human enteric viruses, protozoan parasites and marine biotoxins are also of importance.

  14. Quantitative multiplex detection of pathogen biomarkers

    Energy Technology Data Exchange (ETDEWEB)

    Mukundan, Harshini; Xie, Hongzhi; Swanson, Basil I.; Martinez, Jennifer; Grace, Wynne K.

    2016-02-09

    The present invention addresses the simultaneous detection and quantitative measurement of multiple biomolecules, e.g., pathogen biomarkers through either a sandwich assay approach or a lipid insertion approach. The invention can further employ a multichannel, structure with multi-sensor elements per channel.

  15. Pathogen Pressure Puts Immune Defense into Perspective

    NARCIS (Netherlands)

    Horrocks, Nicholas P. C.; Matson, Kevin D.; Tieleman, B. Irene

    2011-01-01

    The extent to which organisms can protect themselves from disease depends on both the immune defenses they maintain and the pathogens they face. At the same time, immune systems are shaped by the antigens they encounter, both over ecological and evolutionary time. Ecological immunologists often

  16. Control of indigenous pathogenic bacteria in seafood

    DEFF Research Database (Denmark)

    Huss, Hans Henrik

    1997-01-01

    The pathogenic bacteria indigenous to the aquatic and general environment are listed. Their distribution in nature, prevalence in seafood and the possibilities for growth of these organisms in various types of products are outlined These data, combined with what is known regarding the epidemiology...

  17. EPCOT, NASA and plant pathogens in space.

    Science.gov (United States)

    White, R

    1996-01-01

    Cooperative work between NASA and Walt Disney World's EPCOT Land Pavilion is described. Joint efforts include research about allelopathy in multi-species plant cropping in CELSS, LEDs as light sources in hydroponic systems, and the growth of plant pathogens in space.

  18. Quantitative multiplex detection of pathogen biomarkers

    Science.gov (United States)

    Mukundan, Harshini; Xie, Hongzhi; Swanson, Basil I; Martinez, Jennifer; Grace, Wynne K

    2014-10-14

    The present invention addresses the simultaneous detection and quantitative measurement of multiple biomolecules, e.g., pathogen biomarkers through either a sandwich assay approach or a lipid insertion approach. The invention can further employ a multichannel, structure with multi-sensor elements per channel.

  19. Cultural, morphological, pathogenic and molecular characterization ...

    African Journals Online (AJOL)

    Alternaria blotch (Alternaria mali) causes severe foliar damage to apple trees in Kashmir. Twenty one (21) isolates of A. mali were collected from different locations and characterized for cultural, morphological, pathogenic and molecular variations. A. mali colonies varied in their cultural behaviour ranging from velvety to ...

  20. Paleogene radiation of a plant pathogenic mushroom.

    Directory of Open Access Journals (Sweden)

    Martin P A Coetzee

    Full Text Available The global movement and speciation of fungal plant pathogens is important, especially because of the economic losses they cause and the ease with which they are able to spread across large areas. Understanding the biogeography and origin of these plant pathogens can provide insights regarding their dispersal and current day distribution. We tested the hypothesis of a Gondwanan origin of the plant pathogenic mushroom genus Armillaria and the currently accepted premise that vicariance accounts for the extant distribution of the species.The phylogeny of a selection of Armillaria species was reconstructed based on Maximum Parsimony (MP, Maximum Likelihood (ML and Bayesian Inference (BI. A timeline was then placed on the divergence of lineages using a Bayesian relaxed molecular clock approach.Phylogenetic analyses of sequenced data for three combined nuclear regions provided strong support for three major geographically defined clades: Holarctic, South American-Australasian and African. Molecular dating placed the initial radiation of the genus at 54 million years ago within the Early Paleogene, postdating the tectonic break-up of Gondwana.The distribution of extant Armillaria species is the result of ancient long-distance dispersal rather than vicariance due to continental drift. As these finding are contrary to most prior vicariance hypotheses for fungi, our results highlight the important role of long-distance dispersal in the radiation of fungal pathogens from the Southern Hemisphere.

  1. Novel Micro-organisms controlling plant pathogens

    NARCIS (Netherlands)

    Köhl, J.

    2009-01-01

    The invention relates to control of pathogen caused diseases on leaves, fruits and ears in plants, such as apple scab (Venturia inaequalis by treatment of plant with an isolate of Cladosporium cladosporioides. The treatment is effective in both prevention and treatment of the fungal infection

  2. Novel Micro-organisms controlling plant pathogens

    NARCIS (Netherlands)

    Köhl, J.

    2010-01-01

    The invention relates to control of pathogen caused diseases on leaves, fruits and ears in plants, such as apple scab (Venturia inaequalis by treatment of plant with an isolate of Cladosporium cladosporioides. The treatment is effective in both prevention and treatment of the fungal infection

  3. PATHOGENIC POTENTIALS OF ESCHERICHIA COLI ISOLATED ...

    African Journals Online (AJOL)

    Electrolyte and haematological parameters in rabbits infected with pathogenic isolates of Escherichia coli from rural water supplies in Rivers State, Nigeria, where monitored. Rabbits were orally infected with suspension containing 3x107 cfu /ml of Escherichia coli to induce diarrhoea, and the electrolyte (sodium, potassium ...

  4. Microbial minimalism: genome reduction in bacterial pathogens.

    Science.gov (United States)

    Moran, Nancy A

    2002-03-08

    When bacterial lineages make the transition from free-living or facultatively parasitic life cycles to permanent associations with hosts, they undergo a major loss of genes and DNA. Complete genome sequences are providing an understanding of how extreme genome reduction affects evolutionary directions and metabolic capabilities of obligate pathogens and symbionts.

  5. Plastic Transcriptomes Stabilize Immunity to Pathogen Diversity

    DEFF Research Database (Denmark)

    Zhang, Wei; Corwin, Jason A; Copeland, Daniel

    2017-01-01

    To respond to pathogen attack, selection and associated evolution has led to the creation of plant immune system that are a highly effective and inducible defense system. Central to this system are the plant defense hormones jasmonic acid (JA) and salicylic acid (SA) and crosstalk between the two...

  6. Host-pathogen interactions during apoptosis

    Indian Academy of Sciences (India)

    Unknown

    349. Keywords. Antioxidant; baculovirus; host-pathogen; eIF2α-kinase; P35; PKR .... conferring a selective advantage to the virus, the capacity to prevent apoptosis is ..... totic extracts were found to cleave purified PKR in vitro. These findings ...

  7. Plastic transcriptomes stabilize immunity to pathogen diversity

    DEFF Research Database (Denmark)

    Zhang, Wei; Corwin, Jason A.; Copeland, Daniel

    2017-01-01

    To respond to pathogen attack, selection and associated evolution has led to the creation of plant immune system that are a highly effective and inducible defense system. Central to this system are the plant defense hormones jasmonic acid (JA) and salicylic acid (SA) and crosstalk between the two...

  8. Campylobacter jejuni & Inflammation : Grilling the pathogen

    NARCIS (Netherlands)

    Bouwman, L.I.

    2016-01-01

    Campylobacter jejuni is the most common cause of bacterial foodborne disease. Yet, little is known about how this pathogen causes intestinal inflammation. The clinical pathology during human infection points to invasive bacterial behavior accompanied by the induction of potent pro-inflammatory

  9. The making of a new pathogen

    DEFF Research Database (Denmark)

    Stukenbrock, Eva; Bataillon, Thomas; Dutheil, Julien

    2011-01-01

    that gene-rich regions or regions with low recombination experience stronger effects of natural selection on neutral diversity. Emergence of a new agricultural host selected a highly specialized and fast-evolving pathogen with unique evolutionary patterns compared with its wild relatives. The strong impact...

  10. Home Air Purifiers Eradicate Harmful Pathogens

    Science.gov (United States)

    2014-01-01

    Marshall Space Flight Center funded the University of Madison-Wisconsin to develop ethylene scrubbers to keep produce fresh in space. Akida Holdings of Jacksonville, Florida, licensed the technology and developed Airocide, an air purifier that can kill airborne pathogens. Previously designed for industrial spaces, there is now a specially designed unit for home use.

  11. Antibiotic susceptibility profiles of oral pathogens

    NARCIS (Netherlands)

    Veloo, A. C. M.; Seme, K.; Raangs, Gerwin; Rurenga, P.; Singadji, Z.; Wekema - Mulder, G.; van Winkelhoff, A. J.

    2012-01-01

    Periodontitis is a bacterial disease that can be treated with systemic antibiotics. The aim of this study was to establish the antibiotic susceptibility profiles of five periodontal pathogens to six commonly used antibiotics in periodontics. A total of 247 periodontal bacterial isolates were tested

  12. Morphological, cultural, pathogenic and molecular variability ...

    African Journals Online (AJOL)

    Alternaria blight (Alternaria brassicae) causes severe foliar damage to Indian mustard in Uttarakhand. Ten (10) isolates of A. brassicae were collected from different hosts and characterized for cultural, morphological, pathogenic and molecular variations. A. brassicae colonies varied in their cultural behaviour ranging from ...

  13. Ewingella Americana: An Emerging True Pathogen

    Directory of Open Access Journals (Sweden)

    Syed Hassan

    2012-01-01

    Full Text Available Infections caused by Ewingella americana have been rarely reported in the literature. Most of the cases that have been reported were among the immunocompromised patients. We report a case of E. americana causing osteomyelitis and septic arthritis of the shoulder joint in a previous intravenous drug abuser. The causative pathogen was identified by synovial fluid analysis and culture.

  14. Arginase activity in pathogenic and non-pathogenic species of Leishmania parasites.

    Science.gov (United States)

    Badirzadeh, Alireza; Taheri, Tahereh; Taslimi, Yasaman; Abdossamadi, Zahra; Heidari-Kharaji, Maryam; Gholami, Elham; Sedaghat, Baharehsadat; Niyyati, Maryam; Rafati, Sima

    2017-07-01

    Proliferation of Leishmania (L.) parasites depends on polyamine availability, which can be generated by the L-arginine catabolism and the enzymatic activity of arginase (ARG) of the parasites and of the mammalian hosts. In the present study, we characterized and compared the arginase (arg) genes from pathogenic L. major and L. tropica and from non-pathogenic L. tarentolae. We quantified the level of the ARG activity in promastigotes and macrophages infected with pathogenic L. major and L. tropica and non-pathogenic L. tarentolae amastigotes. The ARG's amino acid sequences of the pathogenic and non-pathogenic Leishmania demonstrated virtually 98.6% and 88% identities with the reference L. major Friedlin ARG. Higher ARG activity was observed in all pathogenic promastigotes as compared to non-pathogenic L. tarentolae. In vitro infection of human macrophage cell line (THP1) with pathogenic and non-pathogenic Leishmania spp. resulted in increased ARG activities in the infected macrophages. The ARG activities present in vivo were assessed in susceptible BALB/c and resistant C57BL/6 mice infected with L. major, L. tropica and L. tarentolae. We demonstrated that during the development of the infection, ARG is induced in both strains of mice infected with pathogenic Leishmania. However, in L. major infected BALB/c mice, the induction of ARG and parasite load increased simultaneously according to the time course of infection, whereas in C57BL/6 mice, the enzyme is upregulated solely during the period of footpad swelling. In L. tropica infected mice, the footpads' swellings were slow to develop and demonstrated minimal cutaneous pathology and ARG activity. In contrast, ARG activity was undetectable in mice inoculated with the non-pathogenic L. tarentolae. Our data suggest that infection by Leishmania parasites can increase ARG activity of the host and provides essential polyamines for parasite salvage and its replication. Moreover, the ARG of Leishmania is vital for parasite

  15. Effect of humidity and temperature on the survival of Listeria monocytogenes on surfaces.

    Science.gov (United States)

    Redfern, J; Verran, J

    2017-04-01

    Listeria monocytogenes is a pathogenic bacterium, with human disease and infection linked to dairy products, seafood, ready-to-eat meat and raw & undercooked meats. Stainless steel is the most common food preparation surface and therefore, it is important to understand how food storage conditions such as surface materials, temperature and relative humidity can affect survival of L. monocytogenes. In this study, survival of L. monocytogenes on stainless steel was investigated at three temperatures (4, 10 and 21°C), each approx. 11, 50 and 85% humidity. Results indicate that the lower the temperature, the more cells were recovered in all three humidity environments, while medium humidity enhances survival, irrespective of temperature. Lower humidity decreases recovery at all temperatures. These data support the guidance noted above that humidity control is important, and that lower humidity environments are less likely to support retention of viable L. monocytogenes on a stainless steel surface. Understanding survival of potential food-borne pathogens is essential for the safe production and preparation of food. While it has long been 'common knowledge' that relative humidity can affect the growth and survival of micro-organisms, this study systematically describes the survival of L. monocytogenes on stainless steel under varying humidity and temperatures for the first time. The outcomes from this paper will allow those involved with food manufacture and preparation to make informed judgement on environmental conditions relating to humidity control, which is lacking in the food standards guidelines. © 2017 The Society for Applied Microbiology.

  16. The sunflower downy mildew pathogen Plasmopara halstedii.

    Science.gov (United States)

    Gascuel, Quentin; Martinez, Yves; Boniface, Marie-Claude; Vear, Felicity; Pichon, Magalie; Godiard, Laurence

    2015-02-01

    Downy mildew of sunflower is caused by Plasmopara halstedii (Farlow) Berlese & de Toni. Plasmopara halstedii is an obligate biotrophic oomycete pathogen that attacks annual Helianthus species and cultivated sunflower, Helianthus annuus. Depending on the sunflower developmental stage at which infection occurs, the characteristic symptoms range from young seedling death, plant dwarfing, leaf bleaching and sporulation to the production of infertile flowers. Downy mildew attacks can have a great economic impact on sunflower crops, and several Pl resistance genes are present in cultivars to protect them against the disease. Nevertheless, some of these resistances have been overcome by the occurrence of novel isolates of the pathogen showing increased virulence. A better characterization of P. halstedii infection and dissemination mechanisms, and the identification of the molecular basis of the interaction with sunflower, is a prerequisite to efficiently fight this pathogen. This review summarizes what is currently known about P. halstedii, provides new insights into its infection cycle on resistant and susceptible sunflower lines using scanning electron and light microscopy imaging, and sheds light on the pathogenicity factors of P. halstedii obtained from recent molecular data. Kingdom Stramenopila; Phylum Oomycota; Class Oomycetes; Order Peronosporales; Family Peronosporaceae; Genus Plasmopara; Species Plasmopara halstedii. Sunflower seedling damping off, dwarfing of the plant, bleaching of leaves, starting from veins, and visible white sporulation, initially on the lower side of cotyledons and leaves. Plasmopara halstedii infection may severely impact sunflower seed yield. In spring, germination of overwintered sexual oospores leads to sunflower root infection. Intercellular hyphae are responsible for systemic plant colonization and the induction of disease symptoms. Under humid and fresh conditions, dissemination structures are produced by the pathogen on all

  17. Immunity induced shortly after DNA vaccination of rainbow trout against rhabdoviruses protects against heterologous virus but not against bacterial pathogens

    DEFF Research Database (Denmark)

    Lorenzen, Niels; Lorenzen, Ellen; Einer-Jensen, Katja

    2002-01-01

    whereas no increased survival was found upon challenge with bacterial pathogens. Within two months after vaccination, the cross-protection disappeared while the specific immunity to homologous virus remained high. The early immunity induced by the DNA vaccines thus appeared to involve short-lived non......It was recently reported that DNA vaccination of rainbow trout fingerlings against viral hemorrhagic septicaemia virus (VHSV) induced protection within 8 days after intramuscular injection of plasmid DNA. In order to analyse the specificity of this early immunity, fish were vaccinated with plasmid...... DNA encoding the VHSV or the infectious haematopoietic necrosis virus (IHNV) glycoprotein genes and later challenged with homologous or heterologous pathogens. Challenge experiments revealed that immunity established shortly after vaccination was cross-protective between the two viral pathogens...

  18. Effect of ozonation on microbial fish pathogens, ammonia, nitrate, nitrite, and bod in simulated reuse hatchery water

    Energy Technology Data Exchange (ETDEWEB)

    Colberg, P.J.; Lingg, A.J.

    1978-10-01

    The effectiveness of ozone for eliminating fish pathogens and reducing nitrite, ammonia, and BOD associated with reuse hatchery systems was evaluated. Comparative survival rates of four bacterial fish pathogens and a bacterium-protozoan population during batch and continuous flow ozonation indicated a specific microbial ozone demand during batch treatment and 99% mortality of pathogens during continuous flow treatment. Oxidation of carbon and nitrite by ozone was rapid at low ozone concentrations; carbon and ammonia oxidation rates were pH dependent. The oxidation capacity of ozone in water was greatest at elevated pH even though lower ozone concentrations were used. Ozone treatment appears to be successful for disinfecting hatchery makeup water for recycling. However, the economics of such treatment are yet to be determined. (10 graphs, 28 references, 1 table)

  19. Exploiting amoeboid and non-vertebrate animal model systems to study the virulence of human pathogenic fungi.

    Science.gov (United States)

    Mylonakis, Eleftherios; Casadevall, Arturo; Ausubel, Frederick M

    2007-07-27

    Experiments with insects, protozoa, nematodes, and slime molds have recently come to the forefront in the study of host-fungal interactions. Many of the virulence factors required for pathogenicity in mammals are also important for fungal survival during interactions with non-vertebrate hosts, suggesting that fungal virulence may have evolved, and been maintained, as a countermeasure to environmental predation by amoebae and nematodes and other small non-vertebrates that feed on microorganisms. Host innate immune responses are also broadly conserved across many phyla. The study of the interaction between invertebrate model hosts and pathogenic fungi therefore provides insights into the mechanisms underlying pathogen virulence and host immunity, and complements the use of mammalian models by enabling whole-animal high throughput infection assays. This review aims to assist researchers in identifying appropriate invertebrate systems for the study of particular aspects of fungal pathogenesis.

  20. Exploiting amoeboid and non-vertebrate animal model systems to study the virulence of human pathogenic fungi.

    Directory of Open Access Journals (Sweden)

    Eleftherios Mylonakis

    2007-07-01

    Full Text Available Experiments with insects, protozoa, nematodes, and slime molds have recently come to the forefront in the study of host-fungal interactions. Many of the virulence factors required for pathogenicity in mammals are also important for fungal survival during interactions with non-vertebrate hosts, suggesting that fungal virulence may have evolved, and been maintained, as a countermeasure to environmental predation by amoebae and nematodes and other small non-vertebrates that feed on microorganisms. Host innate immune responses are also broadly conserved across many phyla. The study of the interaction between invertebrate model hosts and pathogenic fungi therefore provides insights into the mechanisms underlying pathogen virulence and host immunity, and complements the use of mammalian models by enabling whole-animal high throughput infection assays. This review aims to assist researchers in identifying appropriate invertebrate systems for the study of particular aspects of fungal pathogenesis.

  1. Exposure to minimally processed pear and melon during shelf life could modify the pathogenic potential of Listeria monocytogenes.

    Science.gov (United States)

    Colás-Medà, Pilar; Viñas, Inmaculada; Oliveira, Márcia; Anguera, Marina; Serrano, Jose C E; Abadias, Maribel

    2017-04-01

    Survival and virulence of foodborne pathogens can be influenced by environmental factors such as the intrinsic properties of food as well as the extrinsic properties that contribute to food shelf life (e.g., temperature and gas atmosphere). The direct contribution of food matrix characteristics on the survival of L. monocytogenes during fresh-cut fruit shelf life is not very well understood. In addition, the gastrointestinal tract is the primary route of listeriosis infection and penetration of the intestinal epithelial cell barrier is the first step in the infection process. Hence, the pathogenic potential of L. monocytogenes, measured as the capability for the organism to survive a simulated gastrointestinal tract and the proportion of cells able to subsequently adhere to and invade differentiated Caco-2 cells, subjected to fresh-cut pear and melon shelf life, was investigated. Samples were inoculated, stored at 10 °C for 7 days and evaluated after inoculation and again after 2 and 7 days of storage. A decrease in L. monocytogenes' capacity to survive a simulated gastrointestinal tract was observed with increasing storage time, regardless of the fruit matrix evaluated. Furthermore, L. monocytogenes placed on fresh-cut pear and melon was subjected to an attachment and invasion assay after crossing the simulated gastrointestinal tract. After inoculation, pathogen on fresh-cut pear showed 5-fold more capacity to adhere to Caco-2 cells than pathogen on fresh-cut melon. After 2 days of storage, L. monocytogenes grown on fresh-cut melon showed similar adhesive capacity (1.11%) than cells grown on pear (1.83%), but cells grown on melon had the higher invasive capacity (0.0093%). We can conclude that minimally processed melon could represent a more important hazard than pear under the studied shelf life. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. THE “CHALLENGING” MULTIDRUG-RESISTANT PATHOGENS OF NOSOCOMIAL INFECTIONS IN CRITICALLY ILL PATIENTS (A LITERATURE REVIEW

    Directory of Open Access Journals (Sweden)

    T. V. Chernenkaya

    2015-01-01

    Full Text Available ABSTRACT. Changes in the structure of the main causative agents of nosocomial infections and significant spread of multidrug­resistant strains of bacteria are a natural biological response for antibiotics that selectively inhibit pathogens and contribute to selection, survival and growth of drug resistant strains of bacteria. In this literature review we present the change of structure of the major causative microorganisms of nosocomial septic infections and theirs resistance to antibiotics for the last 70 years. 

  3. Overexpression of Differentially Expressed Genes Identified in Non-pathogenic and Pathogenic Entamoeba histolytica Clones Allow Identification of New Pathogenicity Factors Involved in Amoebic Liver Abscess Formation.

    Directory of Open Access Journals (Sweden)

    Martin Meyer

    2016-08-01

    Full Text Available We here compared pathogenic (p and non-pathogenic (np isolates of Entamoeba histolytica to identify molecules involved in the ability of this parasite to induce amoebic liver abscess (ALA-like lesions in two rodent models for the disease. We performed a comprehensive analysis of 12 clones (A1-A12 derived from a non-pathogenic isolate HM-1:IMSS-A and 12 clones (B1-B12 derived from a pathogenic isolate HM-1:IMSS-B. "Non-pathogenicity" included the induction of small and quickly resolved lesions while "pathogenicity" comprised larger abscess development that overstayed day 7 post infection. All A-clones were designated as non-pathogenic, whereas 4 out of 12 B-clones lost their ability to induce ALAs in gerbils. No correlation between ALA formation and cysteine peptidase (CP activity, haemolytic activity, erythrophagocytosis, motility or cytopathic activity was found. To identify the molecular framework underlying different pathogenic phenotypes, three clones were selected for in-depth transcriptome analyses. Comparison of a non-pathogenic clone A1np with pathogenic clone B2p revealed 76 differentially expressed genes, whereas comparison of a non-pathogenic clone B8np with B2p revealed only 19 differentially expressed genes. Only six genes were found to be similarly regulated in the two non-pathogenic clones A1np and B8np in comparison with the pathogenic clone B2p. Based on these analyses, we chose 20 candidate genes and evaluated their roles in ALA formation using the respective gene-overexpressing transfectants. We conclude that different mechanisms lead to loss of pathogenicity. In total, we identified eight proteins, comprising a metallopeptidase, C2 domain proteins, alcohol dehydrogenases and hypothetical proteins, that affect the pathogenicity of E. histolytica.

  4. Overexpression of Differentially Expressed Genes Identified in Non-pathogenic and Pathogenic Entamoeba histolytica Clones Allow Identification of New Pathogenicity Factors Involved in Amoebic Liver Abscess Formation.

    Science.gov (United States)

    Meyer, Martin; Fehling, Helena; Matthiesen, Jenny; Lorenzen, Stephan; Schuldt, Kathrin; Bernin, Hannah; Zaruba, Mareen; Lender, Corinna; Ernst, Thomas; Ittrich, Harald; Roeder, Thomas; Tannich, Egbert; Lotter, Hannelore; Bruchhaus, Iris

    2016-08-01

    We here compared pathogenic (p) and non-pathogenic (np) isolates of Entamoeba histolytica to identify molecules involved in the ability of this parasite to induce amoebic liver abscess (ALA)-like lesions in two rodent models for the disease. We performed a comprehensive analysis of 12 clones (A1-A12) derived from a non-pathogenic isolate HM-1:IMSS-A and 12 clones (B1-B12) derived from a pathogenic isolate HM-1:IMSS-B. "Non-pathogenicity" included the induction of small and quickly resolved lesions while "pathogenicity" comprised larger abscess development that overstayed day 7 post infection. All A-clones were designated as non-pathogenic, whereas 4 out of 12 B-clones lost their ability to induce ALAs in gerbils. No correlation between ALA formation and cysteine peptidase (CP) activity, haemolytic activity, erythrophagocytosis, motility or cytopathic activity was found. To identify the molecular framework underlying different pathogenic phenotypes, three clones were selected for in-depth transcriptome analyses. Comparison of a non-pathogenic clone A1np with pathogenic clone B2p revealed 76 differentially expressed genes, whereas comparison of a non-pathogenic clone B8np with B2p revealed only 19 differentially expressed genes. Only six genes were found to be similarly regulated in the two non-pathogenic clones A1np and B8np in comparison with the pathogenic clone B2p. Based on these analyses, we chose 20 candidate genes and evaluated their roles in ALA formation using the respective gene-overexpressing transfectants. We conclude that different mechanisms lead to loss of pathogenicity. In total, we identified eight proteins, comprising a metallopeptidase, C2 domain proteins, alcohol dehydrogenases and hypothetical proteins, that affect the pathogenicity of E. histolytica.

  5. Bacteriophages for detection of bacterial pathogens

    International Nuclear Information System (INIS)

    Kutateladze, M.

    2009-01-01

    The G. Eliava Institute of Bacteriophages, Microbiology and Virology (Tbilisi, Georgia) is one of the most famous institutions focused on bacteriophage research for the elaboration of appropriate phage methodologies for human and animal protection. The main direction of the institute is the study and production of bacteriophages against intestinal disorders (dysentery, typhoid, intesti) and purulent-septic infections (staphylococcus, streptococcus, pyophage, etc.). These preparations were successfully introduced during the Soviet era, and for decades were used throughout the former Soviet Union and in other Socialist countries for the treatment, prophylaxis, and diagnosis of various infectious diseases, including those caused by antibiotic-resistant bacterial strains. Bacteriophages were widely used for identifying and detecting infections caused by the most dangerous pathogens and causative agents of epidemiological outbreaks. The specific topic of this presentation is the phage typing of bacterial species, which can be an important method for epidemiological diagnostics. Together with different genetic methodologies - such as PCR-based methods, PFGE, plasmid fingerprinting, and ribosomal typing - phage typing is one method for identifying bacterial pathogens. The method has a high percentage of determination of phage types, high specificity of reaction, and is easy for interpretation and use by health workers. Phage typing was applied for inter-species differentiation of different species of Salmonella, S. typhi, Brucella spp, Staphylococcus aureus, E. col,i Clostridium deficile, Vibrio cholerae, Yersinia pestis, Yersinia enterocolitica, Lysteria monocytogenes, Clostridium perfringens, Clostridium tetani, plant pathogens, and other bacterial pathogens. In addition to addressing the utility and efficacy of phage typing, the paper will discuss the isolation and selection of diagnostic typing phages for interspecies differentiation of pathogens that is necessary

  6. Elucidating Host-Pathogen Interactions Based on Post-Translational Modifications Using Proteomics Approaches

    DEFF Research Database (Denmark)

    Ravikumar, Vaishnavi; Jers, Carsten; Mijakovic, Ivan

    2015-01-01

    can be efficiently applied to gain an insight into the molecular mechanisms involved. The measurement of the proteome and post-translationally modified proteome dynamics using mass spectrometry, results in a wide array of information, such as significant changes in protein expression, protein...... display host specificity through a complex network of molecular interactions that aid their survival and propagation. Co-infection states further lead to complications by increasing the microbial burden and risk factors. Quantitative proteomics based approaches and post-translational modification analysis...... pathogen interactions....

  7. Quantifying climate change impacts on runoff of zoonotic pathogens from land

    Science.gov (United States)

    Sterk, Ankie; de Roda Husman, Ana Maria; Stergiadi, Maria; de Nijs, Ton; Schijven, Jack

    2013-04-01

    Several studies have shown a correlation between rainfall and waterborne disease outbreaks. One of the mechanisms whereby rainfall may cause outbreaks is through an increase in runoff of animal faeces from fields to surface waters. Faeces originating from wildlife, domestic animals or manure-fertilized fields, is considered an important source of zoonotic pathogens to which people may be exposed by water recreation or drinking-water consumption. Climate changes affect runoff because of increasing winter precipitation and more extreme precipitation events, as well as changes in evaporation. Furthermore, drier summers are leading to longer periods of high soil moisture deficits, increasing the hydrophobicity of soil and consequently changing infiltration capacities. A conceptual model is designed to describe the impacts of climate changes on the terrestrial and aquatic ecosystems, which are both directly and indirectly affecting pathogen loads in the environment and subsequent public health risks. One of the major outcomes was the lack of quantitative data and limited qualitative analyses of impacts of climate changes on pathogen runoff. Quantifying the processes by which micro-organisms are transported from fields to waters is important to be able to estimate such impacts to enable targeted implementation of effective intervention measures. A quantitative model using Mathematica software will be developed to estimate concentrations of pathogens originating from overland flow during runoff events. Different input sources will be included by applying different land-use scenarios, including point source faecal pollution from dairy cows and geese and diffuse source pollution by fertilization. Zoonotic pathogens, i.e. Cryptosporidium and Campylobacter, were selected based on transport properties, faecal loads and disease burden. Transport and survival rates of these pathogens are determined including effects of changes in precipitation but also temperature induced

  8. A Brazilian social bee must cultivate fungus to survive.

    Science.gov (United States)

    Menezes, Cristiano; Vollet-Neto, Ayrton; Marsaioli, Anita Jocelyne; Zampieri, Davila; Fontoura, Isabela Cardoso; Luchessi, Augusto Ducati; Imperatriz-Fonseca, Vera Lucia

    2015-11-02

    The nests of social insects provide suitable microenvironments for many microorganisms as they offer stable environmental conditions and a rich source of food [1-4]. Microorganisms in turn may provide several benefits to their hosts, such as nutrients and protection against pathogens [1, 4-6]. Several examples of symbiosis between social insects and microorganisms have been found in ants and termites. These symbioses have driven the evolution of complex behaviors and nest structures associated with the culturing of the symbiotic microorganisms [5, 7, 8]. However, while much is known about these relationships in many species of ants and termites, symbiotic relationships between microorganisms and social bees have been poorly explored [3, 4, 9, 10]. Here, we report the first case of an obligatory relationship between the Brazilian stingless bee Scaptotrigona depilis and a fungus of the genus Monascus (Ascomycotina). Fungal mycelia growing on the provisioned food inside the brood cell are eaten by the larva. Larvae reared in vitro on sterilized larval food supplemented with fungal mycelia had a much higher survival rate (76%) compared to larvae reared under identical conditions but without fungal mycelia (8% survival). The fungus was found to originate from the material from which the brood cells are made. Since the bees recycle and transport this material between nests, fungus would be transferred to newly built cells and also to newly founded nests. This is the first report of a fungus cultivation mutualism in a social bee. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Resting spore formation of aphid-pathogenic fungus Pandora nouryi depends on the concentration of infective inoculum.

    Science.gov (United States)

    Huang, Zhi-Hong; Feng, Ming-Guang

    2008-07-01

    Resting spore formation of some aphid-pathogenic Entomophthorales is important for the seasonal pattern of their prevalence and survival but this process is poorly understood. To explore the possible mechanism involved in the process, Pandora nouryi (obligate aphid pathogen) interacted with green peach aphid Myzus persicae on cabbage leaves under favourable conditions. Host nymphs showered with primary conidia of an isolate (LC(50): 0.9-6.7 conidia mm(-2) 4-7 days post shower) from air captures in the low-latitude plateau of China produced resting spores (azygospores), primary conidia or both spore types. Surprisingly, the proportion of mycosed cadavers forming resting spores (P(CFRS)) increased sharply within the concentrations (C) of 28-240 conidia mm(-2), retained high levels at 240-1760, but was zero or extremely low at 0.3-16. The P(CFRS)-C relationship fit well the logistic equation P(CFRS) = 0.6774/[1 + exp(3.1229-0.0270C)] (r(2) = 0.975). This clarified for the first time the dependence of in vivo resting spore formation of P. nouryi upon the concentration of infective inoculum. A hypothesis is thus proposed that some sort of biochemical signals may exist in the host-pathogen interaction so that the fungal pathogen perceives the signals for prompt response to forthcoming host-density changes by either producing conidia for infecting available hosts or forming resting spores for surviving host absence in situ.

  10. Surviving Scientific Academia . . . and Beyond

    Energy Technology Data Exchange (ETDEWEB)

    Conlin, Jeremy Lloyd [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-02-03

    It's been 16 years since I first took a physics class at Weber State University. Since them, I've survived graduate school in Nuclear Engineering, and a postdoc appointment doing nuclear nonproliferation. Now I'm a Technical Staff Member at Los Alamos National Laboratory working with nuclear data, the physics behind the numerical simulations of nuclear reactors and nuclear weapons. Along the way, I've learned a few things. First, scientific computing is everywhere in science. If you are not writing codes, you will be analyzing their output, and generally there will be more output than a human can correctly and accurately interpret in a timely manner. Second, a career in science or engineering can be very rewarding with opportunities to collaborate with and generate friendships with very bright people from all over the world.

  11. Additive interaction in survival analysis

    DEFF Research Database (Denmark)

    Rod, Naja Hulvej; Lange, Theis; Andersen, Ingelise

    2012-01-01

    It is a widely held belief in public health and clinical decision-making that interventions or preventive strategies should be aimed at patients or population subgroups where most cases could potentially be prevented. To identify such subgroups, deviation from additivity of absolute effects...... an empirical example of interaction between education and smoking on risk of lung cancer. We argue that deviations from additivity of effects are important for public health interventions and clinical decision-making, and such estimations should be encouraged in prospective studies on health. A detailed...... is the relevant measure of interest. Multiplicative survival models, such as the Cox proportional hazards model, are often used to estimate the association between exposure and risk of disease in prospective studies. In Cox models, deviations from additivity have usually been assessed by surrogate measures...

  12. Survivable pulse power space radiator

    Science.gov (United States)

    Mims, James; Buden, David; Williams, Kenneth

    1989-01-01

    A thermal radiator system is described for use on an outer space vehicle, which must survive a long period of nonuse and then radiate large amounts of heat for a limited period of time. The radiator includes groups of radiator panels that are pivotally connected in tandem, so that they can be moved to deployed configuration wherein the panels lie largely coplanar, and to a stowed configuration wherein the panels lie in a stack to resist micrometeorite damage. The panels are mounted on a boom which separates a hot power source from a payload. While the panels are stowed, warm fluid passes through their arteries to keep them warm enough to maintain the coolant in a liquid state and avoid embrittlement of material. The panels can be stored in a largely cylindrical shell, with panels progressively further from the boom being of progressively shorter length.

  13. Riboflavin-ultraviolet light pathogen reduction treatment does not impact the immunogenicity of murine red blood cells.

    Science.gov (United States)

    Tormey, Christopher A; Santhanakrishnan, Manjula; Smith, Nicole H; Liu, Jingchun; Marschner, Susanne; Goodrich, Raymond P; Hendrickson, Jeanne E

    2016-04-01

    Ultraviolet (UV) illumination/pathogen reduction effectively inactivates white blood cells (WBCs) in whole blood. Given that cotransfused WBCs may impact recipient immune responses, we hypothesized that pathogen reduction of whole blood may alter responses to RBC antigens. Transgenic mice expressing a model (HOD) antigen, authentic human (hGPA or KEL) antigens, or natural fluorescence (uGFP) on their RBCs were utilized as blood donors. Recipients were transfused with fresh whole blood to which riboflavin had been added or fresh whole blood treated by UV illumination/pathogen reduction treatment after the addition of riboflavin. Posttransfusion RBC recovery, survival, and alloimmunization were measured by flow cytometry. UV illumination/pathogen reduction treatment did not alter RBC antigen expression, and recipients of treated syngeneic RBCs had persistently negative direct antiglobulin tests. Greater than 75% of treated and untreated syngeneic RBCs were recovered 24 hours posttransfusion in all experiments, although alterations in the long-term posttransfusion survival of treated RBCs were observed. Treated and untreated KEL RBCs induced similar recipient alloimmune responses, with all recipients making anti-KEL glycoprotein immunoglobulins (p > 0.05). Alloimmune responses to treated HOD or hGPA RBCs were no different from untreated RBCs (p > 0.05). Pathogen inactivation treatment of fresh whole murine blood with riboflavin and UV illumination does not impact the rate or magnitude of RBC alloimmunization to three distinct RBC antigens. Further, UV illumination/pathogen reduction appears safe from an immunohematologic standpoint, with no immunogenic neoantigens detected on treated murine RBCs. Future studies with fresh and stored human RBCs are warranted to confirm these findings. © 2015 AABB.

  14. Fingertip replantation: determinants of survival.

    Science.gov (United States)

    Li, Jing; Guo, Zheng; Zhu, Qingsheng; Lei, Wei; Han, Yisheng; Li, Mingquan; Wang, Zhen

    2008-09-01

    The purpose of this study was to determine the risk factors for an unsuccessful replanted fingertip. Two hundred eleven complete fingertip amputations in 211 patients who underwent replantation surgery between August of 1990 and March of 2006 were included in this study. The patients' age, gender, smoking history, digit position, dominant hand, amputation level, injury mechanism, platelet count, ischemia time, preservation method of the amputated part, anesthesia, number of arteries repaired, venous drainage, use of vein grafting, neurorrhaphy, bone shortening, and smoking after operation were tested for their impact on fingertip survival. One hundred seventy-two of 211 patients (81.5 percent) had a successful replantation. Univariate analysis showed crush or avulsion injury, high platelet count, and inappropriate preservation of the amputated part in saline solution or ethanol to be associated with a high incidence of replantation failure. Twenty-two of 54 patients (41 percent) who had a crush or avulsion trauma had failed replantation. Logistic regression analysis identified injury mechanism, platelet count, smoking after operation, preservation method of the amputated part, and the use of vein grafting as statistically significant predictive factors for success or failure. Injury mechanism, platelet count, smoking after operation, preservation method of amputated part, and the use of vein grafting were found to be the main predictors for the survival of the replanted fingertip. Applying external bleeding in zone 1 and venous drainage through the medullary cavity in zone 2 or venous anastomosis combined with vein grafting rather than venous anastomosis alone were strongly recommended in the fingertip replantation of crush or avulsion injury.

  15. Genetic diversity in the oral pathogen Porphyromonas gingivalis: molecular mechanisms and biological consequences

    Science.gov (United States)

    Tribble, Gena D; Kerr, Jennifer E; Wang, Bing-Yan

    2013-01-01

    Porphyromonas gingivalis is a Gram-negative anaerobic bacterium that colonizes the human oral cavity. It is implicated in the development of periodontitis, a chronic periodontal disease affecting half of the adult population in the USA. To survive in the oral cavity, these bacteria must colonize dental plaque biofilms in competition with other bacterial species. Long-term survival requires P. gingivalis to evade host immune responses, while simultaneously adapting to the changing physiology of the host and to alterations in the plaque biofilm. In reflection of this highly variable niche, P. gingivalis is a genetically diverse species and in this review the authors summarize genetic diversity as it relates to pathogenicity in P. gingivalis. Recent studies revealing a variety of mechanisms by which adaptive changes in genetic content can occur are also reviewed. Understanding the genetic plasticity of P. gingivalis will provide a better framework for understanding the host–microbe interactions associated with periodontal disease. PMID:23642116

  16. The sensitivity of bacterial foodborne pathogens to Croton blanchetianus Baill essential oil

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    Geiseanny Fernandes do Amarante Melo

    2013-12-01

    Full Text Available The aim of this study was to assess the activity of essential oil extracted from the leaves of C. blanchetianus Baill, popularly known as "marmeleiro", in inhibiting the growth and survival of pathogenic microorganisms in food by determining their survival in vitro and by observing the behaviour of Listeria monocytogenes inoculated into a food model (meat cubes that was stored at refrigeration temperature (7 ± 1 ºC for 4 days. The results indicated a bactericidal effect against Aeromonas hydrophila and Listeria monocytogenes and bacteriostatic action against Salmonella Enteritidis. A bacteriostatic effect on meat contaminated with L. monocytogenes was found for all concentrations of essential oils tested. These results showed that essential oil from the leaves of C. blanchetianus Baill represents an alternative source of potentially natural antimicrobial agents that may be used as a food preservative.

  17. Recent developments in pathogen detection arrays: implications for fungal plant pathogens and use in practica

    NARCIS (Netherlands)

    Lievens, B.; Thomma, B.P.H.J.

    2005-01-01

    The failure to adequately identify plant pathogens from culture-based morphological techniques has led to the development of culture-independent molecular approaches. Increasingly, diagnostic laboratories are pursuing fast routine methods that provide reliable identification, sensitive detection,

  18. THE OUTER MEMBRANE OF PATHOGENIC REPRESENTATIVES OF THE LEPTOSPIRA GENIUS

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    A. N. Vaganova

    2011-01-01

    Full Text Available Abstract. Pathogenic leptospires can infect wide spectrum of hosts and they can survive in the environment long time. The outer membrane is the cellular component participated in interaction of microorganisms and environment. In present time several proteins located in the outer membrane of leptospires which are responsible for colonization of host organism, protection from influence of immune system of host, transport of substances in to the cell and other processes have been described. The outer membrane contains proteins and lipopolysaccharide molecules which have citotoxic effect. It was shown that regulation of protein composition of membranes depends on several factors of environment such as temperature, osmolarity, presence of certain substances in environment. Lipopolysaccharide and protein molecules of outer membranes have antigenic properties. These molecules can be used in practice as the components of vaccine against leptospiroses and diagnostic tools. Current review summarize information concerning structural organization of the outer membrane of leptospires, diversities of incoming parts of molecules and regulation of their synthesis. Moreover, perspectives of practical using of the outer membrane components in diagnostics and prevention of leptospiroses are presented.

  19. Pathogens of wild maned wolves (Chrysocyon brachyurus) in Brazil.

    Science.gov (United States)

    de Almeida Curi, Nelson Henrique; Coelho, Carlyle Mendes; de Campos Cordeiro Malta, Marcelo; Magni, Elisa Maria Vaz; Sábato, Marco Aurelio Lima; Araújo, Amanda Soriano; Lobato, Zelia Inês Portela; Santos, Juliana Lúcia Costa; Santos, Hudson Andrade; Ragozo, Alessandra Alves Mara; de Souza, Silvio Luís Pereira

    2012-10-01

    The maned wolf, Chrysocyon brachyurus, is an endangered Neotropical canid that survives at low population densities. Diseases are a potential threat for its conservation but to date have been poorly studied. We performed clinical evaluations and investigated the presence of infectious diseases through serology and coprologic tests on maned wolves from Galheiro Natural Private Reserve, Perdizes City, Minas Gerais State, southeastern Brazil. Fifteen wolves were captured between 2003 and 2008. We found high prevalences of antibody to canine distemper virus (CDV; 13/14), canine parvovirus (CPV; 4/14), canine adenovirus type 2 (13/14), canine coronavirus (5/11), canine parainfluenza virus (5/5), and Toxoplasma gondii (6/8), along with Ancylostomidae eggs in all feces samples. Antibodies against Leishmania sp. were found in one of 10 maned wolves, and all samples were negative for Neospora caninum. Evidence of high exposure to these viral agents was also observed in unvaccinated domestic dogs from neighboring farms. High prevalence of viral agents and parasites such as CDV, CPV, and Ancylostomidae indicates that this population faces considerable risk of outbreaks and chronic debilitating parasites. This is the first report of exposure to canine parainfluenza virus in Neotropical free-ranging wild canids. Our findings highlight that canine pathogens pose a serious hazard to the viability of maned wolves and other wild carnivore populations in the area and emphasize the need for monitoring and protecting wildlife health in remaining fragments of the Cerrado biome.

  20. Brucella abortus: pathogenicity and gene regulation of virulence

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    Olga Rivas-Solano

    2015-06-01

    Full Text Available Brucella abortus is a zoonotic intracellular facultative pathogen belonging to the subdivision α2 of class Proteobacteria. It causes a worldwide distributed zoonotic disease called brucellosis. The main symptoms are abortion and sterility in cattle, as well as an undulant febrile condition in humans. In endemic regions like Central America, brucellosis has a high socioeconomic impact. A basic research project was recently conducted at the ITCR with the purpose of studying gene regulation of virulence, structure and immunogenicity in B. abortus. The present review was written as part of this project. B. abortus virulence seems to be determined by its ability to invade, survive and replicate inside professional and non-professional phagocytes. It reaches its intracellular replicative niche without the activation of host antimicrobial mechanisms of innate immunity. It also has gene regulation mechanisms for a rapid adaptation to an intracellular environment such as the two-component signal transduction system BvrR/BvrS and the quorum sensing regulator called Vjbr, as well as other transcription factors. All of them integrate a complex gene regulation network.