WorldWideScience

Sample records for bacteria revealsdifferent strategies

  1. The Evolution of Two-Component Systems in Bacteria RevealsDifferent Strategies for Niche Adaptation

    Energy Technology Data Exchange (ETDEWEB)

    Alm, Eric; Huang, Katherine; Arkin, Adam

    2006-09-13

    Two-component systems including histidine protein kinasesrepresent the primary signal transduction paradigm in prokaryoticorganisms. To understand how these systems adapt to allow organisms todetect niche-specific signals, we analyzed the phylogenetic distributionof nearly 5000 histidine protein kinases from 207 sequenced prokaryoticgenomes. We found that many genomes carry a large repertoire of recentlyevolved signaling genes, which may reflect selective pressure to adapt tonew environmental conditions. Both lineage-specific gene family expansionand horizontal gene transfer play major roles in the introduction of newhistidine kinases into genomes; however, there are differences in howthese two evolutionary forces act. Genes imported via horizontal transferare more likely to retain their original functionality as inferred from asimilar complement of signaling domains, while gene family expansionaccompanied by domain shuffling appears to be a major source of novelgenetic diversity. Family expansion is the dominantsource of newhistidine kinase genes in the genomes most enriched in signalingproteins, and detailed analysis reveals that divergence in domainstructure and changes in expression patterns are hallmarks of recentexpansions. Finally, while these two modes of gene acquisition arewidespread across bacterial taxa, there are clear species-specificpreferences for which mode is used.

  2. Current strategies for improving food bacteria

    NARCIS (Netherlands)

    Kuipers, O P; Buist, Girbe; Kok, Jan

    2000-01-01

    Novel concepts and methodologies are emerging that hold great promise for the directed improvement of food-related bacteria, specifically lactic acid bacteria. Also, the battle against food spoilage and pathogenic bacteria can now be fought more effectively. Here we describe recent advances in

  3. SOS, the formidable strategy of bacteria against aggressions.

    Science.gov (United States)

    Baharoglu, Zeynep; Mazel, Didier

    2014-11-01

    The presence of an abnormal amount of single-stranded DNA in the bacterial cell constitutes a genotoxic alarm signal that induces the SOS response, a broad regulatory network found in most bacterial species to address DNA damage. The aim of this review was to point out that beyond being a repair process, SOS induction leads to a very strong but transient response to genotoxic stress, during which bacteria can rearrange and mutate their genome, induce several phenotypic changes through differential regulation of genes, and sometimes acquire characteristics that potentiate bacterial survival and adaptation to changing environments. We review here the causes and consequences of SOS induction, but also how this response can be modulated under various circumstances and how it is connected to the network of other important stress responses. In the first section, we review articles describing the induction of the SOS response at the molecular level. The second section discusses consequences of this induction in terms of DNA repair, changes in the genome and gene expression, and sharing of genomic information, with their effects on the bacteria's life and evolution. The third section is about the fine tuning of this response to fit with the bacteria's 'needs'. Finally, we discuss recent findings linking the SOS response to other stress responses. Under these perspectives, SOS can be perceived as a powerful bacterial strategy against aggressions. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  4. Metabolic strategies of beer spoilage lactic acid bacteria in beer.

    Science.gov (United States)

    Geissler, Andreas J; Behr, Jürgen; von Kamp, Kristina; Vogel, Rudi F

    2016-01-04

    Beer contains only limited amounts of readily fermentable carbohydrates and amino acids. Beer spoilage lactic acid bacteria (LAB) have to come up with metabolic strategies in order to deal with selective nutrient content, high energy demand of hop tolerance mechanisms and a low pH. The metabolism of 26 LAB strains of 6 species and varying spoilage potentialwas investigated in order to define and compare their metabolic capabilities using multivariate statistics and outline possible metabolic strategies. Metabolic capabilities of beer spoilage LAB regarding carbohydrate and amino acids did not correlate with spoilage potential, but with fermentation type (heterofermentative/homofermentative) and species. A shift to mixed acid fermentation by homofermentative (hof) Pediococcus claussenii and Lactobacillus backii was observed as a specific feature of their growth in beer. For heterofermentative (hef) LAB a mostly versatile carbohydrate metabolism could be demonstrated, supplementing the known relevance of organic acids for their growth in beer. For hef LAB a distinct amino acid metabolism, resulting in biogenic amine production, was observed, presumably contributing to energy supply and pH homeostasis.

  5. 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.

  6. Elucidation of bacteria found in car interiors and strategies to reduce the presence of potential pathogens

    Science.gov (United States)

    Stephenson, Rachel E.; Gutierrez, Daniel; Peters, Cindy; Nichols, Mark; Boles, Blaise R.

    2014-01-01

    The human microbiome is influenced by a number of factors, including environmental exposure to microbes. Because many humans spend a large amount of time in built environments, it can be expected that the microbial ecology of these environments will influence the human microbiome. In an attempt to further understand the microbial ecology of built environments, the microbiota of car interiors was analyzed using culture dependent and culture independent methods. While it was found that the number and type of bacteria varied widely among the cars and sites tested, Staphylococcus and Propionibacterium were nearly always the dominant genera found at the locations sampled. Because Staphylococcus is of particular concern to human health, the characteristics of this genus found in car interiors were investigated. Staphylococcus epidermidis, S. aureus, and S. warnerii were the most prevalent staphylococcal species found, and 22.6% of S. aureus strains isolated from shared community vehicles were resistant to methicillin. The reduction in the prevalence of pathogenic bacteria in cars by using silver-based antimicrobial surface coatings was also evaluated. Coatings containing 5% silver ion additives were applied to steering wheels, placed in cars for five months and were found to eliminate the presence of culturable pathogenic bacteria recovered from these sites relative to controls. Together, these results provide new insight into the microbiota found in an important built environment, the automobile, and potential strategies for controlling the presence of human pathogens. PMID:24564823

  7. Evolutionary strategies of viruses, bacteria and archaea in hydrothermal vent ecosystems revealed through metagenomics.

    Science.gov (United States)

    Anderson, Rika E; Sogin, Mitchell L; Baross, John A

    2014-01-01

    The deep-sea hydrothermal vent habitat hosts a diverse community of archaea and bacteria that withstand extreme fluctuations in environmental conditions. Abundant viruses in these systems, a high proportion of which are lysogenic, must also withstand these environmental extremes. Here, we explore the evolutionary strategies of both microorganisms and viruses in hydrothermal systems through comparative analysis of a cellular and viral metagenome, collected by size fractionation of high temperature fluids from a diffuse flow hydrothermal vent. We detected a high enrichment of mobile elements and proviruses in the cellular fraction relative to microorganisms in other environments. We observed a relatively high abundance of genes related to energy metabolism as well as cofactors and vitamins in the viral fraction compared to the cellular fraction, which suggest encoding of auxiliary metabolic genes on viral genomes. Moreover, the observation of stronger purifying selection in the viral versus cellular gene pool suggests viral strategies that promote prolonged host integration. Our results demonstrate that there is great potential for hydrothermal vent viruses to integrate into hosts, facilitate horizontal gene transfer, and express or transfer genes that manipulate the hosts' functional capabilities.

  8. Evolutionary strategies of viruses, bacteria and archaea in hydrothermal vent ecosystems revealed through metagenomics.

    Directory of Open Access Journals (Sweden)

    Rika E Anderson

    Full Text Available The deep-sea hydrothermal vent habitat hosts a diverse community of archaea and bacteria that withstand extreme fluctuations in environmental conditions. Abundant viruses in these systems, a high proportion of which are lysogenic, must also withstand these environmental extremes. Here, we explore the evolutionary strategies of both microorganisms and viruses in hydrothermal systems through comparative analysis of a cellular and viral metagenome, collected by size fractionation of high temperature fluids from a diffuse flow hydrothermal vent. We detected a high enrichment of mobile elements and proviruses in the cellular fraction relative to microorganisms in other environments. We observed a relatively high abundance of genes related to energy metabolism as well as cofactors and vitamins in the viral fraction compared to the cellular fraction, which suggest encoding of auxiliary metabolic genes on viral genomes. Moreover, the observation of stronger purifying selection in the viral versus cellular gene pool suggests viral strategies that promote prolonged host integration. Our results demonstrate that there is great potential for hydrothermal vent viruses to integrate into hosts, facilitate horizontal gene transfer, and express or transfer genes that manipulate the hosts' functional capabilities.

  9. Non-anthocyanin polyphenolic transformation by native yeast and bacteria co-inoculation strategy during vinification.

    Science.gov (United States)

    Devi, Apramita; Archana, Kodira Muthanna; Bhavya, Panikuttria Kuttappa; Anu-Appaiah, Konerira Aiyappaa

    2018-02-01

    Co-inoculation has been adapted by many wine-producing countries because it enhances the success of malolactic fermentation and reduces the fermentation cost, as well as time. However, wine phenolics have been sparsely highlighted during co-inoculation, even though polyphenols are an important parameter affecting wine colour, astringency and aroma. In the present study, we investigated the impact of co-inoculation on non-anthocyanin polyphenol profile for two different grape varieties. Co-inoculation of native yeast strain (AAV2) along with Oenococcus oeni was adapted for Cabernet Sauvignon and Shiraz wine. It was observed that the co-inoculation had minimal yet significant impact on the phenolic composition of wines for both the grape varieties. Color loss, as well as fruity aroma development, was observed in co-inoculated wines. The wines were on a par with the commercial wine, as well as wines without malolactic fermentation, in terms of phenolic compounds and overall organoleptic acceptance. Principal component analysis and hierarchical cluster analysis further suggested that the varietal influence on phenolic composition was dominating compared to inoculation strategies. Among the varieties, the inoculation strategies have significantly influenced the Cabernet wines compared to Shiraz wines. The results of the present study demonstrate that the phenolic compounds are not drastically affected by metabolic activities of malolactic bacteria during co-inoculation and, hence, are equally suitable for wine fermentation. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  10. Rumen bacteria at work: bioaugmentation strategies to enhance biogas production from cow manure.

    Science.gov (United States)

    Ozbayram, E G; Akyol, Ç; Ince, B; Karakoç, C; Ince, O

    2018-02-01

    To investigate the effects of different bioaugmentation strategies for enhancing the biogas production from cow manure and evaluate microbial community patterns. Co-inoculation with cow rumen fluid and cow rumen-derived enriched microbial consortia was evaluated in anaerobic batch tests at 36°C and 41°C. Singular addition of both rumen fluid and enriched bioaugmentation culture had a promising enhancement on methane yields; however, the highest methane yield (311 ml CH 4 per gram VS at 41°C) was achieved when the anaerobic seed sludge was co-inoculated together with rumen fluid and enriched bioaugmentation culture. Bacterial community profiles were investigated by Ion PGM Platform, and specific lignocellulolytic bacteria dynamics in batch tests were assessed by qPCR. The temperature had minor effects on the abundance of bacterial community; in which Bacteroidetes and Firmicutes were the most abundant phyla in all digesters. Furthermore, Rikenellaceae, Clostridiaceae, Porphyromonadaceae, Bacteroidaceae and Ruminococcaceae played a crucial role during the anaerobic degradation of cow manure. There was an important impact of Firmicutes flavefaciens and Ruminococcus albus at 41°C, which in turn positively affected the methane production. The degree of enhancement in biogas production can be upgraded by the co-inoculation of rumen-derived bioaugmentation culture with anaerobic seed sludge with high methanogenic activity. A close look at the biotic interactions and their associations with abiotic factors might be valuable for evaluating rumen-related bioaugmentation applications. © 2017 The Society for Applied Microbiology.

  11. Exploring Post-Treatment Reversion of Antimicrobial Resistance in Enteric Bacteria of Food Animals as a Resistance Mitigation Strategy.

    Science.gov (United States)

    Volkova, Victoriya V; KuKanich, Butch; Riviere, Jim E

    2016-11-01

    Antimicrobial drug use in food animals is associated with an elevation in relative abundance of bacteria resistant to the drug among the animal enteric bacteria. Some of these bacteria are potential foodborne pathogens. Evidence suggests that at least in the enteric nontype-specific Escherichia coli, after treatment the resistance abundance reverts to the background pre-treatment levels, without further interventions. We hypothesize that it is possible to define the distribution of the time period after treatment within which resistance to the administered drug, and possibly other drugs in case of coselection, in fecal bacteria of the treated animals returns to the background pre-treatment levels. Furthermore, it is possible that a novel resistance mitigation strategy for microbiological food safety could be developed based on this resistance reversion phenomenon. The strategy would be conceptually similar to existing antimicrobial drug withdrawal periods, which is a well-established and accepted mitigation strategy for avoiding violative drug residues in the edible products from the treated animals. For developing resistance-relevant withdrawals, a mathematical framework can be used to join the necessary pharmacological, microbiological, and animal production components to project the distributions of the post-treatment resistance reversion periods in the production animal populations for major antimicrobial drug classes in use. The framework can also help guide design of empirical studies into the resistance-relevant withdrawal periods and development of mitigation approaches to reduce the treatment-associated elevation of resistance in animal enteric bacteria. We outline this framework, schematically and through exemplar equations, and how its components could be formulated.

  12. MALDI-TOF MS Andromas strategy for the routine identification of bacteria, mycobacteria, yeasts, Aspergillus spp. and positive blood cultures.

    Science.gov (United States)

    Bille, E; Dauphin, B; Leto, J; Bougnoux, M-E; Beretti, J-L; Lotz, A; Suarez, S; Meyer, J; Join-Lambert, O; Descamps, P; Grall, N; Mory, F; Dubreuil, L; Berche, P; Nassif, X; Ferroni, A

    2012-11-01

    All organisms usually isolated in our laboratory are now routinely identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) using the Andromas software. The aim of this study was to describe the use of this strategy in a routine clinical microbiology laboratory. The microorganisms identified included bacteria, mycobacteria, yeasts and Aspergillus spp. isolated on solid media or extracted directly from blood cultures. MALDI-TOF MS was performed on 2665 bacteria isolated on solid media, corresponding to all bacteria isolated during this period except Escherichia coli grown on chromogenic media. All acquisitions were performed without extraction. After a single acquisition, 93.1% of bacteria grown on solid media were correctly identified. When the first acquisition was not contributory, a second acquisition was performed either the same day or the next day. After two acquisitions, the rate of bacteria identified increased to 99.2%. The failures reported on 21 strains were due to an unknown profile attributed to new species (9) or an insufficient quality of the spectrum (12). MALDI-TOF MS has been applied to 162 positive blood cultures. The identification rate was 91.4%. All mycobacteria isolated during this period (22) were correctly identified by MALDI-TOF MS without any extraction. For 96.3% and 92.2% of yeasts and Aspergillus spp., respectively, the identification was obtained with a single acquisition. After a second acquisition, the overall identification rate was 98.8% for yeasts (160/162) and 98.4% (63/64) for Aspergillus spp. In conclusion, the MALDI-TOF MS strategy used in this work allows a rapid and efficient identification of all microorganisms isolated routinely. © 2011 The Authors. Clinical Microbiology and Infection © 2011 European Society of Clinical Microbiology and Infectious Diseases.

  13. Engineering strategies aimed at control of acidification rate of lactic acid bacteria

    DEFF Research Database (Denmark)

    Martinussen, Jan; Solem, Christian; Holm, Anders Koefoed

    2013-01-01

    The ability of lactic acid bacteria to produce lactic acid from various sugars plays an important role in food fermentations. Lactic acid is derived from pyruvate, the end product of glycolysis and thus a fast lactic acid production rate requires a high glycolytic flux. In addition to lactic acid......, alternative end products - ethanol, acetic acid and formic acid - are formed by many species. The central role of glycolysis in lactic acid bacteria has provoked numerous studies aiming at identifying potential bottleneck(s) since knowledge about flux control could be important not only for optimizing food...

  14. Plant growth promoting bacteria as an alternative strategy for salt tolerance in plants: A review.

    Science.gov (United States)

    Numan, Muhammad; Bashir, Samina; Khan, Yasmin; Mumtaz, Roqayya; Shinwari, Zabta Khan; Khan, Abdul Latif; Khan, Ajmal; Al-Harrasi, Ahmed

    2018-04-01

    Approximately 5.2 billion hectare agriculture land are affected by erosion, salinity and soil degradation. Salinity stress has significantly affecting the fertile lands, and therefore possesses a huge impact on the agriculture and economy of a country. Salt stress has severe effects on the growth and development of plants as well as reducing its yield. Plants are inherently equipped with stress tolerance ability to responds the specific type of stress. Plants retained specific mechanisms for salt stress mitigation, such as hormonal stimulation, ion exchange, antioxidant enzymes and activation of signaling cascades on their metabolic and genetic frontiers that sooth the stressed condition. Additional to the plant inherent mechanisms, certain plant growth promoting bacteria (PGPB) also have specialized mechanism that play key role for salt stress tolerance and plant growth promotion. These bacteria triggers plants to produce different plant growth hormones like auxin, cytokinine and gibberellin as well as volatile organic compounds. These bacteria also produces growth regulators like siderophore, which fix nitrogen, solubilize organic and inorganic phosphate. Considering the importance of PGPB in compensation of salt tolerance in plants, the present study has reviewed the different aspect and mechanism of bacteria that play key role in promoting plants growth and yield. It can be concluded that PGPB can be used as a cost effective and economical tool for salinity tolerance and growth promotion in plants. Copyright © 2018 Elsevier GmbH. All rights reserved.

  15. Distinct Osmoadaptation Strategies in the Strict Halophilic and Halotolerant Bacteria Isolated from Lunsu Salt Water Body of North West Himalayas.

    Science.gov (United States)

    Vaidya, Shivani; Dev, Kamal; Sourirajan, Anuradha

    2018-07-01

    Two strict halophilic bacterial strains, Halobacillus trueperi SS1, and Halobacillus trueperi SS3, and three halotolerant bacterial strains, Shewanella algae SS2, Halomonas venusta SS5, and Marinomonas sp. SS8 of Lunsu salt water body, Himachal Pradesh, India, were selected to study the mechanism of salt tolerance and the role of osmolytes therein. A combination of flame photometry, chromatographic and colorimetric assays was used to study the mechanism of salt tolerance in the selected strict halophilic and halotolerant bacterial strains. The strict halophiles and, one of the halotolerants, Marinomonas sp. SS8 were found to utilize both "salt-in strategy" and "accumulation of compatible solutes strategy" for osmoregulation in hypersaline conditions. On the contrary, the remaining two halotolerants used "accumulation of compatible solutes strategy" under saline stress and not the "salt-in strategy". The present study suggests towards distinct mechanisms of salt tolerance in the two classes, wherein strict halophiles accumulate compatible solutes as well as adopt salt-in strategy, while the halotolerant bacteria accumulate a range of compatible solutes, except Marinomonas sp. SS8, which utilizes both the strategies to combat salt stress.

  16. Resistance in bacteria of the food chain: epidemiology and control strategies

    DEFF Research Database (Denmark)

    Aarestrup, Frank Møller; Wegener, Henrik Caspar; Collignon, P.

    2008-01-01

    quantification of the transmission difficult. The exposure of humans to antimicrobial resistance from food animals can be controlled by either limiting the selective pressure from antimicrobial usage or by limiting the spread of the bacteria/genes. A number of control options are reviewed, including drug...... licensing, removing financial incentives, banning or restricting the use of certain drugs, altering prescribers behavior, improving animal health, improving hygiene and implementing microbial criteria for certain types of resistant pathogens for use in the control of trade of both food animals and food.......Bacteria have evolved multiple mechanisms for the efficient evolution and spread of antimicrobial resistance. Modern food production facilitates the emergence and spread of resistance through the intensive use of antimicrobial agents and international trade of both animals and food products...

  17. Strategies for removal of indicator pathogenic bacteria from commercial harvested shellfish

    OpenAIRE

    Jones, S; Howell, T; O'Neill, K; Langan, R

    1992-01-01

    The Great Bay/Piscataqua River Estuary in New Hampshire and Maine has an abundant oyster resource in sewage-contaminated water. The only approved area in the Maine portion of the Estuary is Spinney Creek, where fecal indicator bacteria are present at reduced levels and Vibrio vulnificus is absent. Spinney Creek Oyster Company (SCOC) of Eliot, Maine, operates relay lagoons and a depuration facility for oysters harvested commercially from restricted areas of the Salmon Falls River in Maine. Oys...

  18. Resistance in bacteria of the food chain: epidemiology and control strategies

    DEFF Research Database (Denmark)

    Cavaco, Lina; Aarestrup, Frank Møller

    2013-01-01

    Antimicrobial agents are widely used for treatment of animals and humans as well as for production purposes in livestock production in several countries. This is exerting a major selective pressure on bacterial populations, and is selecting for populations resistant to the antimicrobials used....... The emergence and spread of resistant bacteria in the food chain is a major concern as food-producing animals may constitute a huge reservoir for antimicrobial resistance. Furthermore, food animals and food of animal origin is traded worldwide, which means that the occurrences of antimicrobial resistance...

  19. Heavy Metal Resistance Strategies of Acidophilic Bacteria and Their Acquisition: Importance for Biomining and Bioremediation

    Directory of Open Access Journals (Sweden)

    Claudio A Navarro

    2013-01-01

    Full Text Available Microbial solubilizing of metals in acid environments is successfully used in industrial bioleaching of ores or biomining to extract metals such as copper, gold, uranium and others. This is done mainly by acidophilic and other microorganisms that mobilize metals and generate acid mine drainage or AMD, causing serious environmental problems. However, bioremediation or removal of the toxic metals from contaminated soils can be achieved by using the specific properties of the acidophilic microorganisms interacting with these elements. These bacteria resist high levels of metals by using a few "canonical" systems such as active efflux or trapping of the metal ions by metal chaperones. Nonetheless, gene duplications, the presence of genomic islands, the existence of additional mechanisms such as passive instruments for pH and cation homeostasis in acidophiles and an inorganic polyphosphate-driven metal resistance mechanism have also been proposed. Horizontal gene transfer in environmental microorganisms present in natural ecosystems is considered to be an important mechanism in their adaptive evolution. This process is carried out by different mobile genetic elements, including genomic islands (GI, which increase the adaptability and versatility of the microorganism. This mini-review also describes the possible role of GIs in metal resistance of some environmental microorganisms of importance in biomining and bioremediation of metal polluted environments such as Thiomonas arsenitoxydans, a moderate acidophilic microorganism, Acidithiobacillus caldus and Acidithiobacillus ferrooxidans strains ATCC 23270 and ATCC 53993, all extreme acidophiles able to tolerate exceptionally high levels of heavy metals. Some of these bacteria contain variable numbers of GIs, most of which code for high numbers of genes related to metal resistance. In some cases there is an apparent correlation between the number of metal resistance genes and the metal tolerance of each

  20. Single-Cell Analysis of Growth in Budding Yeast and Bacteria Reveals a Common Size Regulation Strategy.

    Science.gov (United States)

    Soifer, Ilya; Robert, Lydia; Amir, Ariel

    2016-02-08

    To maintain a constant cell size, dividing cells have to coordinate cell-cycle events with cell growth. This coordination has long been supposed to rely on the existence of size thresholds determining cell-cycle progression [1]. In budding yeast, size is controlled at the G1/S transition [2]. In agreement with this hypothesis, the size at birth influences the time spent in G1: smaller cells have a longer G1 period [3]. Nevertheless, even though cells born smaller have a longer G1, the compensation is imperfect and they still bud at smaller cell sizes. In bacteria, several recent studies have shown that the incremental model of size control, in which size is controlled by addition of a constant volume (in contrast to a size threshold), is able to quantitatively explain the experimental data on four different bacterial species [4-7]. Here, we report on experimental results for the budding yeast Saccharomyces cerevisiae, finding, surprisingly, that cell size control in this organism is very well described by the incremental model, suggesting a common strategy for cell size control with bacteria. Additionally, we argue that for S. cerevisiae the "volume increment" is not added from birth to division, but rather between two budding events. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Multiplicity of Mathematical Modeling Strategies to Search for Molecular and Cellular Insights into Bacteria Lung Infection.

    Science.gov (United States)

    Cantone, Martina; Santos, Guido; Wentker, Pia; Lai, Xin; Vera, Julio

    2017-01-01

    Even today two bacterial lung infections, namely pneumonia and tuberculosis, are among the 10 most frequent causes of death worldwide. These infections still lack effective treatments in many developing countries and in immunocompromised populations like infants, elderly people and transplanted patients. The interaction between bacteria and the host is a complex system of interlinked intercellular and the intracellular processes, enriched in regulatory structures like positive and negative feedback loops. Severe pathological condition can emerge when the immune system of the host fails to neutralize the infection. This failure can result in systemic spreading of pathogens or overwhelming immune response followed by a systemic inflammatory response. Mathematical modeling is a promising tool to dissect the complexity underlying pathogenesis of bacterial lung infection at the molecular, cellular and tissue levels, and also at the interfaces among levels. In this article, we introduce mathematical and computational modeling frameworks that can be used for investigating molecular and cellular mechanisms underlying bacterial lung infection. Then, we compile and discuss published results on the modeling of regulatory pathways and cell populations relevant for lung infection and inflammation. Finally, we discuss how to make use of this multiplicity of modeling approaches to open new avenues in the search of the molecular and cellular mechanisms underlying bacterial infection in the lung.

  2. Interventional strategies and current clinical experience with carbapenemase-producing Gram-negative bacteria.

    Science.gov (United States)

    Akova, M; Daikos, G L; Tzouvelekis, L; Carmeli, Y

    2012-05-01

    The wide dissemination of carbapenemase-producing Gram-negatives (CPGNs), including enterobacterial species and non-fermenters, has caused a public health crisis of global dimensions. These organisms cause serious infections in hospitalized patients, and are associated with increased mortality. Cross-transmission is common, and outbreaks may occur in healthcare facilities where the infection control practices are inadequate. CPGNs exhibit extensive drug-resistant phenotypes, complicate therapy, and limit treatment options. Systematic data on therapy are limited. However, regimens combining two or more active agents seem to be more efficacious than monotherapy in carbapenemase-producing Klebsiella pneumoniae infections. Strict infection control measures, including active surveillance for timely detection of colonized patients, separation of carriers from non-carriers, and contact precautions, are of utmost importance, and may be the only effective way of preventing the introduction and transmission of these bacteria in healthcare settings. © 2012 The Authors. Clinical Microbiology and Infection © 2012 European Society of Clinical Microbiology and Infectious Diseases.

  3. Engineered biomaterial and biophysical stimulation as combinatorial strategies to address prosthetic infection by pathogenic bacteria.

    Science.gov (United States)

    Boda, Sunil Kumar; Basu, Bikramjit

    2017-10-01

    A plethora of antimicrobial strategies are being developed to address prosthetic infection. The currently available methods for implant infection treatment include the use of antibiotics and revision surgery. Among the bacterial strains, Staphylococcus species pose significant challenges particularly, with regard to hospital acquired infections. In order to combat such life threatening infectious diseases, researchers have developed implantable biomaterials incorporating nanoparticles, antimicrobial reinforcements, surface coatings, slippery/non-adhesive and contact killing surfaces. This review discusses a few of the biomaterial and biophysical antimicrobial strategies, which are in the developmental stage and actively being pursued by several research groups. The clinical efficacy of biophysical stimulation methods such as ultrasound, electric and magnetic field treatments against prosthetic infection depends critically on the stimulation protocol and parameters of the treatment modality. A common thread among the three biophysical stimulation methods is the mechanism of bactericidal action, which is centered on biophysical rupture of bacterial membranes, the generation of reactive oxygen species (ROS) and bacterial membrane depolarization evoked by the interference of essential ion-transport. Although the extent of antimicrobial effect, normally achieved through biophysical stimulation protocol is insufficient to warrant therapeutic application, a combination of antibiotic/ROS inducing agents and biophysical stimulation methods can elicit a clinically relevant reduction in viable bacterial numbers. In this review, we present a detailed account of both the biomaterial and biophysical approaches for achieving maximum bacterial inactivation. Summarizing, the biophysical stimulation methods in a combinatorial manner with material based strategies can be a more potent solution to control bacterial infections. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B

  4. Dual Recognition Strategy for Specific and Sensitive Detection of Bacteria Using Aptamer-Coated Magnetic Beads and Antibiotic-Capped Gold Nanoclusters.

    Science.gov (United States)

    Cheng, Dan; Yu, Mengqun; Fu, Fei; Han, Weiye; Li, Gan; Xie, Jianping; Song, Yang; Swihart, Mark T; Song, Erqun

    2016-01-05

    Food poisoning and infectious diseases caused by pathogenic bacteria such as Staphylococcus aureus (SA) are serious public health concerns. A method of specific, sensitive, and rapid detection of such bacteria is essential and important. This study presents a strategy that combines aptamer and antibiotic-based dual recognition units with magnetic enrichment and fluorescent detection to achieve specific and sensitive quantification of SA in authentic specimens and in the presence of much higher concentrations of other bacteria. Aptamer-coated magnetic beads (Apt-MB) were employed for specific capture of SA. Vancomycin-stabilized fluorescent gold nanoclusters (AuNCs@Van) were prepared by a simple one-step process and used for sensitive quantification of SA in the range of 32-10(8) cfu/mL with the detection limit of 16 cfu/mL via a fluorescence intensity measurement. And using this strategy, about 70 cfu/mL of SA in complex samples (containing 3 × 10(8) cfu/mL of other different contaminated bacteria) could be successfully detected. In comparison to prior studies, the developed strategy here not only simplifies the preparation procedure of the fluorescent probes (AuNCs@Van) to a great extent but also could sensitively quantify SA in the presence of much higher concentrations of other bacteria directly with good accuracy. Moreover, the aptamer and antibiotic used in this strategy are much less expensive and widely available compared to common-used antibodies, making it cost-effective. This general aptamer- and antibiotic-based dual recognition strategy, combined with magnetic enrichment and fluorescent detection of trace bacteria, shows great potential application in monitoring bacterial food contamination and infectious diseases.

  5. Synonymous codon ordering: a subtle but prevalent strategy of bacteria to improve translational efficiency.

    Directory of Open Access Journals (Sweden)

    Zhu-Qing Shao

    Full Text Available BACKGROUND: In yeast coding sequences, once a particular codon has been used, subsequent occurrence of the same amino acid tends to use codons sharing the same tRNA. Such a phenomenon of co-tRNA codons pairing bias (CTCPB is also found in some other eukaryotes but it is not known whether it occurs in prokaryotes. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we focused on a total of 773 bacterial genomes to investigate their synonymous codon pairing preferences. After calculating the actual frequencies of synonymous codon pairs and comparing them with their expected values, we detected an obvious pairing bias towards identical codon pairs. This seems consistent with the previously reported CTCPB phenomenon, since identical codons are certainly read by the same tRNA. However, among co-tRNA but non-identical codon pairs, only 22 were often found overrepresented, suggesting that many co-tRNA codons actually do not preferentially pair together in prokaryotes. Therefore, the previously reported co-tRNA codons pairing rule needs to be more rigorously defined. The affinity differences between a tRNA anticodon and its readable codons should be taken into account. Moreover, both within-gene-shuffling tests and phylogenetic analyses support the idea that translational selection played an important role in shaping the observed synonymous codon pairing pattern in prokaryotes. CONCLUSIONS: Overall, a high level of synonymous codon pairing bias was detected in 73% investigated bacterial species, suggesting the synonymous codon ordering strategy has been prevalently adopted by prokaryotes to improve their translational efficiencies. The findings in this study also provide important clues to better understand the complex dynamics of translational process.

  6. Strategies for Pathogen Biocontrol Using Lactic Acid Bacteria and Their Metabolites: A Focus on Meat Ecosystems and Industrial Environments

    Directory of Open Access Journals (Sweden)

    Patricia Castellano

    2017-07-01

    Full Text Available The globalization of trade and lifestyle ensure that the factors responsible for the emergence of diseases are more present than ever. Despite biotechnology advancements, meat-based foods are still under scrutiny because of the presence of pathogens, which causes a loss of consumer confidence and consequently a fall in demand. In this context, Lactic Acid Bacteria (LAB as GRAS organisms offer an alternative for developing pathogen-free foods, particularly avoiding Listeria monocytogenes, with minimal processing and fewer additives while maintaining the foods’ sensorial characteristics. The use of LAB strains, enabling us to produce antimicrobial peptides (bacteriocins in addition to lactic acid, with an impact on quality and safety during fermentation, processing, and/or storage of meat and ready-to-eat (RTE meat products, constitutes a promising tool. A number of bacteriocin-based strategies including the use of bioprotective cultures, purified and/or semi-purified bacteriocins as well as their inclusion in varied packaging materials under different storage conditions, have been investigated. The application of bacteriocins as part of hurdle technology using non-thermal technologies was explored for the preservation of RTE meat products. Likewise, considering that food contamination with L. monocytogenes is a consequence of the post-processing manipulation of RTE foods, the role of bacteriocinogenic LAB in the control of biofilms formed on industrial surfaces is also discussed.

  7. Strategies for Pathogen Biocontrol Using Lactic Acid Bacteria and Their Metabolites: A Focus on Meat Ecosystems and Industrial Environments

    Science.gov (United States)

    Castellano, Patricia; Pérez Ibarreche, Mariana; Fontana, Cecilia; Vignolo, Graciela M.

    2017-01-01

    The globalization of trade and lifestyle ensure that the factors responsible for the emergence of diseases are more present than ever. Despite biotechnology advancements, meat-based foods are still under scrutiny because of the presence of pathogens, which causes a loss of consumer confidence and consequently a fall in demand. In this context, Lactic Acid Bacteria (LAB) as GRAS organisms offer an alternative for developing pathogen-free foods, particularly avoiding Listeria monocytogenes, with minimal processing and fewer additives while maintaining the foods’ sensorial characteristics. The use of LAB strains, enabling us to produce antimicrobial peptides (bacteriocins) in addition to lactic acid, with an impact on quality and safety during fermentation, processing, and/or storage of meat and ready-to-eat (RTE) meat products, constitutes a promising tool. A number of bacteriocin-based strategies including the use of bioprotective cultures, purified and/or semi-purified bacteriocins as well as their inclusion in varied packaging materials under different storage conditions, have been investigated. The application of bacteriocins as part of hurdle technology using non-thermal technologies was explored for the preservation of RTE meat products. Likewise, considering that food contamination with L. monocytogenes is a consequence of the post-processing manipulation of RTE foods, the role of bacteriocinogenic LAB in the control of biofilms formed on industrial surfaces is also discussed. PMID:28696370

  8. Patterns of bacteria-host associations suggest different ecological strategies between two reef building cold-water coral species

    Science.gov (United States)

    Meistertzheim, Anne.-Leila; Lartaud, Franck; Arnaud-Haond, Sophie; Kalenitchenko, Dimitri; Bessalam, Manon; Le Bris, Nadine; Galand, Pierre E.

    2016-08-01

    Cold-water corals (CWC) are main ecosystem engineers of the deep sea, and their reefs constitute hot-spots of biodiversity. However, their ecology remains poorly understood, particularly, the nature of the holobiont formed by corals with their associated bacterial communities. Here, we analyzed Madrepora oculata and Lophelia pertusa samples, collected from one location in a Mediterranean canyon in two different seasons (autumn and spring), in order to test for species specificity and temporal stability of the host-bacteria associations. The 16S rRNA sequencing revealed host-specific patterns of bacterial communities associated with L. pertusa and M. oculata, both in terms of community composition and diversity. All analyzed M. oculata polyps exhibited temporally and spatially similar bacterial communities dominated by haplotypes homologous to the known cnidarians-associated genus Endozoicomonas. In contrast, the bacterial communities associated with L. pertusa varied among polyps from the same colony, as well as among distinct colonies and between seasons. While the resilient consortium formed by M. oculata and its bacterial community fit the definition of holobiont, the versatility of the L. pertusa microbiome suggests that this association is more influenced by the environmental conditions or nutritional status. Our results thus highlight distinct host/microbes association strategies for these two closely related Scleractinians sharing the same habitat, suggesting distinct sensitivity to environmental change.

  9. A Trojan-Horse Strategy Including a Bacterial Suicide Action for the Efficient Use of a Specific Gram-Positive Antibiotic on Gram-Negative Bacteria.

    Science.gov (United States)

    Schalk, Isabelle J

    2018-05-10

    In the alarming context of rising bacterial antibiotic resistance, there is an urgent need to discover new antibiotics or increase and/or enlarge the activity of those currently in use. The need for new antibiotics is even more urgent in the case of Gram-negative bacteria, such as Acinetobacter, Pseudomonas, and Enterobacteria, which have become resistant to many antibiotics and have an outer membrane with very low permeability to drugs. Vectorization of antibiotics using siderophores may be a solution to bypass such a bacterial wall: the drugs use the iron transporters of the outer membrane as gates to enter bacteria in a Trojan-horse strategy. Designing siderophore-antibiotics that can cross outer membranes has become almost routine, but their transport across the inner membrane is still a limiting step, as well as a strategy that allows dissociation of the antibiotic from the siderophore once inside the bacteria. Liu et al. ( J. Med. Chem. 2018 , DOI: 10.1021/acs.jmedchem.8b00218 ) report the synthesis of a siderophore-cephalosporin compound and demonstrate that β-lactams, such as cephalosporins, can serve as β-lactamase-triggered releasable linkers to allow intracellular delivery of Gram-positive antibiotics to Gram-negative bacteria.

  10. Strategies to increase the hygienic and economic value of fresh fish: Biopreservation using lactic acid bacteria of marine origin.

    Science.gov (United States)

    Gómez-Sala, Beatriz; Herranz, Carmen; Díaz-Freitas, Belén; Hernández, Pablo E; Sala, Ana; Cintas, Luis M

    2016-04-16

    In this work we describe the development of a biopreservation strategy for fresh fish based on the use of bacteriocinogenic LAB of marine origin. For this purpose, two multibacteriocinogenic LAB strains, Lactobacillus curvatus BCS35 and Enterococcus faecium BNM58, previously isolated from fish and fish products were selected owing to their capability to inhibit the growth of several fish-spoilage and food-borne pathogenic bacteria. Two commercially important fish species were chosen, young hake (Merluccius merluccius) and megrim (Lepidorhombus boscii), and the specimens were acquired at the Marín (Pontevedra, Spain) retail fish market, after one night in the chilled hold of a near-shore fishing vessel. The biopreservation potential and the application strategies of these two LAB strains were first tested at a laboratory scale, where several batches of fresh fish were inoculated with: (i) the multibacteriocinogenic LAB culture(s) as protective culture(s); and/or (ii) their cell-free culture supernatant(s) as food ingredient(s), and (iii) the lyophilized bacteriocin preparation(s) as lyophilized food ingredient(s). All batches were stored in polystyrene boxes, permanently filled with ice at 0-2 °C, for 14 days. Microbiological analyses, as well as sensorial analyses, were carried out during the biopreservation trials. Subsequently, Lb. curvatus BCS35 was selected to up-scale the trials, and combinations of the three application methods were assayed. For this purpose, this strain was grown in a semi-industrial scale fermentor (150l) in modified MRS broth, and three batches of fresh fish were inoculated with the protective culture and/or food ingredient, and stored on ice in a chilled chamber at 0-2 °C at the Marín retail fish market for 14 days. Microbiological analyses were carried out during the storage period, showing that when Lb. curvatus BCS35 culture or the corresponding cell-free culture supernatant was used as protective culture or food ingredient

  11. Draft Genome of Scalindua rubra, Obtained from the Interface Above the Discovery Deep Brine in the Red Sea, Sheds Light on Potential Salt Adaptation Strategies in Anammox Bacteria.

    Science.gov (United States)

    Speth, Daan R; Lagkouvardos, Ilias; Wang, Yong; Qian, Pei-Yuan; Dutilh, Bas E; Jetten, Mike S M

    2017-07-01

    Several recent studies have indicated that members of the phylum Planctomycetes are abundantly present at the brine-seawater interface (BSI) above multiple brine pools in the Red Sea. Planctomycetes include bacteria capable of anaerobic ammonium oxidation (anammox). Here, we investigated the possibility of anammox at BSI sites using metagenomic shotgun sequencing of DNA obtained from the BSI above the Discovery Deep brine pool. Analysis of sequencing reads matching the 16S rRNA and hzsA genes confirmed presence of anammox bacteria of the genus Scalindua. Phylogenetic analysis of the 16S rRNA gene indicated that this Scalindua sp. belongs to a distinct group, separate from the anammox bacteria in the seawater column, that contains mostly sequences retrieved from high-salt environments. Using coverage- and composition-based binning, we extracted and assembled the draft genome of the dominant anammox bacterium. Comparative genomic analysis indicated that this Scalindua species uses compatible solutes for osmoadaptation, in contrast to other marine anammox bacteria that likely use a salt-in strategy. We propose the name Candidatus Scalindua rubra for this novel species, alluding to its discovery in the Red Sea.

  12. Anaerobic bacteria

    Science.gov (United States)

    Anaerobic bacteria are bacteria that do not live or grow when oxygen is present. In humans, these bacteria ... Brook I. Diseases caused by non-spore-forming anaerobic bacteria. In: Goldman L, Schafer AI, eds. Goldman-Cecil ...

  13. Elaboration of highly hydrophobic polymeric surface — a potential strategy to reduce the adhesion of pathogenic bacteria?

    Energy Technology Data Exchange (ETDEWEB)

    Poncin-Epaillard, F., E-mail: fabienne.poncin-epaillard@univ-lemans.fr [Institut des Molécules et Matériaux du Mans (IMMM), département Polymères, Colloïdes et Interfaces, UMR CNRS 6283 Université LUNAM, av. O. Messiaen, 72085 Le Mans (France); Herry, J.M. [INRA-AgroParisTech, UMR 1319 MICALIS, équipe B2HM, 25 avenue de la République, 91300 Massy (France); Marmey, P.; Legeay, G. [CTTM, 20 rue Thalès de Milet 72000 Le Mans (France); Debarnot, D. [Institut des Molécules et Matériaux du Mans (IMMM), département Polymères, Colloïdes et Interfaces, UMR CNRS 6283 Université LUNAM, av. O. Messiaen, 72085 Le Mans (France); Bellon-Fontaine, M.N. [INRA-AgroParisTech, UMR 1319 MICALIS, équipe B2HM, 25 avenue de la République, 91300 Massy (France)

    2013-04-01

    Different polymeric surfaces have been modified in order to reach a high hydrophobic character, indeed the superhydrophobicity property. For this purpose, polypropylene and polystyrene have been treated by RF or μwaves CF{sub 4} plasma with different volumes, the results were compared according to the density of injected power. The effect of pretreatment such as mechanical abrasion or plasma activation was also studied. The modified surfaces were shown as hydrophobic, or even superhydrophobic depending of defects density. They were characterized by measurement of wettability and roughness at different scales, i.e. macroscopic, mesoscopic and atomic. It has been shown that a homogeneous surface at the macroscopic scale could be heterogeneous at lower mesoscopic scale. This was associated with the crystallinity of the material. The bioadhesion tests were performed with Gram positive and negative pathogenic strains: Listeria monocytogenes, Pseudomonas aeruginosa and Hafnia alvei. They have demonstrated an antibacterial efficiency of very hydrophobic and amorphous PS treated for all strains tested and a strain-dependent efficiency with modified PP surface being very heterogeneous at the mesoscopic scale. Thus, these biological results pointed out not only the respective role of the surface chemistry and topography in bacterial adhesion, but also the dependence on the peaks and valley distribution at bacteria dimension scale. Highlights: ► Simple, eco-friendly modification of polymers leading to highly hydrophobic property ► Plasma treatment inducing surface fluorination and roughness ► Study of non-adhesion of different types of bacteria onto such polymeric surfaces ► Dependence of their non-adhesion on surface topography whatever their characteristics.

  14. Antibiotics from predatory bacteria

    Directory of Open Access Journals (Sweden)

    Juliane Korp

    2016-03-01

    Full Text Available Bacteria, which prey on other microorganisms, are commonly found in the environment. While some of these organisms act as solitary hunters, others band together in large consortia before they attack their prey. Anecdotal reports suggest that bacteria practicing such a wolfpack strategy utilize antibiotics as predatory weapons. Consistent with this hypothesis, genome sequencing revealed that these micropredators possess impressive capacities for natural product biosynthesis. Here, we will present the results from recent chemical investigations of this bacterial group, compare the biosynthetic potential with that of non-predatory bacteria and discuss the link between predation and secondary metabolism.

  15. Design, characterization and applications of new ionic liquid matrices for multifunctional analysis of biomolecules: A novel strategy for pathogenic bacteria biosensing

    International Nuclear Information System (INIS)

    Abdelhamid, Hani Nasser; Khan, M Shahnawaz; Wu, Hui-Fen

    2014-01-01

    Highlights: • Design and characterize novel UV absorbed-ionic liquid matrices series. • Apply the new series for different analytes. • Introduce a novel methodology for pathogenic bacteria biosensing. • Tabulate the physical parameters of the new series. - Abstract: The design, preparation and performance for novel UV-light absorbing (room-temperature) ionic liquid matrices (UV-RTILMs) for matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) were reported. A series of UV-RTILMs was prepared by ultrasonication of equimolar of acid (mefenamic acid) and bases (aniline (ANI), pyridine (Pyr), dimethyl aniline (DMANI) and 2-methyl picoline (2-P)). The UV-RTILMs have not only significant absorbance at the desired wavelength (337 nm of the N 2 Laser), but also have available protons that can easily undergo proton transfer reactions to ionize the target molecules. The novel UV-RTILMs have the ability to ionize different and wide classes of compounds such as drugs, carbohydrate, and amino acids. The new UV-RTILMs series have been successfully and selectively applied for biosensing the lysates of pathogenic bacteria in the presence of the cell macromolecules. A new strategy for biosensing pathogens was presented via sensing the pathogens lysate in the cell suspension. The new materials can effectively detect the bacterial toxins without separation or any pretreatment. They offered excellent ionization of labile oligosaccharides with protonated peaks. They could significantly enhance the analyte signals, produce homogeneous spotting, reducing spot-to-spot variation, excellent vacuum stability, higher ion peak intensity, and wide application possibility. The physical parameters such as molar refractivity, molar volume, parachor, surface tension, density and polarizability were calculated and tabulated. The new UV-RTILMs could offer excellent reproducibility and great repeatability and they are promising matrices for wide applications on MALDI-MS

  16. Design, characterization and applications of new ionic liquid matrices for multifunctional analysis of biomolecules: A novel strategy for pathogenic bacteria biosensing

    Energy Technology Data Exchange (ETDEWEB)

    Abdelhamid, Hani Nasser [Department of Chemistry, National Sun Yat-Sen University, Kaohsiung, 804, Taiwan (China); Department of Chemistry, Assuit University, Assuit, 71515 (Egypt); Khan, M Shahnawaz [Doctoral Degree Program in Marine Biotechnology, National Sun Yat-Sen University, Kaohsiung, 804, Taiwan (China); Wu, Hui-Fen, E-mail: hwu@faculty.nsysu.edu.tw [Department of Chemistry, National Sun Yat-Sen University, Kaohsiung, 804, Taiwan (China); School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, 800, Taiwan (China); Institute of Medical Science and Technology, National Sun Yat-Sen University, Kaohsiung, 804, Taiwan (China); Doctoral Degree Program in Marine Biotechnology, National Sun Yat-Sen University, Kaohsiung, 804, Taiwan (China); Center for Nanoscience and Nanotechnology, National Sun Yat-Sen University, Kaohsiung, 804, Taiwan (China)

    2014-05-01

    Highlights: • Design and characterize novel UV absorbed-ionic liquid matrices series. • Apply the new series for different analytes. • Introduce a novel methodology for pathogenic bacteria biosensing. • Tabulate the physical parameters of the new series. - Abstract: The design, preparation and performance for novel UV-light absorbing (room-temperature) ionic liquid matrices (UV-RTILMs) for matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) were reported. A series of UV-RTILMs was prepared by ultrasonication of equimolar of acid (mefenamic acid) and bases (aniline (ANI), pyridine (Pyr), dimethyl aniline (DMANI) and 2-methyl picoline (2-P)). The UV-RTILMs have not only significant absorbance at the desired wavelength (337 nm of the N{sub 2} Laser), but also have available protons that can easily undergo proton transfer reactions to ionize the target molecules. The novel UV-RTILMs have the ability to ionize different and wide classes of compounds such as drugs, carbohydrate, and amino acids. The new UV-RTILMs series have been successfully and selectively applied for biosensing the lysates of pathogenic bacteria in the presence of the cell macromolecules. A new strategy for biosensing pathogens was presented via sensing the pathogens lysate in the cell suspension. The new materials can effectively detect the bacterial toxins without separation or any pretreatment. They offered excellent ionization of labile oligosaccharides with protonated peaks. They could significantly enhance the analyte signals, produce homogeneous spotting, reducing spot-to-spot variation, excellent vacuum stability, higher ion peak intensity, and wide application possibility. The physical parameters such as molar refractivity, molar volume, parachor, surface tension, density and polarizability were calculated and tabulated. The new UV-RTILMs could offer excellent reproducibility and great repeatability and they are promising matrices for wide applications on MALDI-MS.

  17. Use of a mixed culture strategy to isolate halophilic bacteria with antibacterial and cytotoxic activity from the Manaure solar saltern in Colombia.

    Science.gov (United States)

    Conde-Martínez, Natalia; Acosta-González, Alejandro; Díaz, Luis E; Tello, Edisson

    2017-12-08

    Water evaporation in solar salterns creates salinity gradients that promote the adaptation of microbial species to different salinities. This competitive habitat challenges the metabolic capabilities of microorganisms and promotes alterations in their production of secondary metabolites. Thus, solar salterns are a potentially important source of new natural products. In Colombia, the most important and representative solar saltern is located in Manaure (La Guajira) in the north of Colombia. The aim of this study was to develop an alternative screening strategy to select halophilic bacteria as producers of bioactive compounds from mixed microbial cultures rather than individual environmental isolates. Brine and sediment samples from different ponds (across a salinity gradient) were inoculated in seven different culture media to grow bacteria and archaea, allowing for a total of 40 different mixed cultures. An organic extract from each mixed culture was obtained and tested against multidrug resistant pathogens, including Klebsiella pneumoniae, vancomycin-resistant Enterococcus faecium, methicillin-resistant Staphylococcus aureus and Bacillus subtilis. In addition, the extracts were tested against two human cancer cell lines, cervical adenocarcinoma (SiHa) and lung carcinoma (A-549). Twenty-four of the forty extracts from mixed cultures obtained from brine and sediment samples from the Manaure solar saltern showed antibacterial activity against Bacillus subtilis. Two extracts, referred to as A1SM3-29 and A1SM3-36, were also active against a methicillin-resistant Staphylococcus aureus, with the latter extract also showing slight cytotoxic activity against the assayed human lung cancer cell line. From this mixed culture, nine isolates were cultivated, and their extracts were tested against the same pathogens, resulting in the identification of a Vibrio sp. strain (A1SM3-36-8) with antimicrobial activity that was similar to that observed for the mixed culture extract

  18. Design, characterization and applications of new ionic liquid matrices for multifunctional analysis of biomolecules: a novel strategy for pathogenic bacteria biosensing.

    Science.gov (United States)

    Abdelhamid, Hani Nasser; Khan, M Shahnawaz; Wu, Hui-Fen

    2014-05-01

    The design, preparation and performance for novel UV-light absorbing (room-temperature) ionic liquid matrices (UV-RTILMs) for matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) were reported. A series of UV-RTILMs was prepared by ultrasonication of equimolar of acid (mefenamic acid) and bases (aniline (ANI), pyridine (Pyr), dimethyl aniline (DMANI) and 2-methyl picoline (2-P)). The UV-RTILMs have not only significant absorbance at the desired wavelength (337 nm of the N2 Laser), but also have available protons that can easily undergo proton transfer reactions to ionize the target molecules. The novel UV-RTILMs have the ability to ionize different and wide classes of compounds such as drugs, carbohydrate, and amino acids. The new UV-RTILMs series have been successfully and selectively applied for biosensing the lysates of pathogenic bacteria in the presence of the cell macromolecules. A new strategy for biosensing pathogens was presented via sensing the pathogens lysate in the cell suspension. The new materials can effectively detect the bacterial toxins without separation or any pretreatment. They offered excellent ionization of labile oligosaccharides with protonated peaks. They could significantly enhance the analyte signals, produce homogeneous spotting, reducing spot-to-spot variation, excellent vacuum stability, higher ion peak intensity, and wide application possibility. The physical parameters such as molar refractivity, molar volume, parachor, surface tension, density and polarizability were calculated and tabulated. The new UV-RTILMs could offer excellent reproducibility and great repeatability and they are promising matrices for wide applications on MALDI-MS. Copyright © 2014. Published by Elsevier B.V.

  19. Big bacteria

    DEFF Research Database (Denmark)

    Schulz, HN; Jørgensen, BB

    2001-01-01

    A small number of prokaryotic species have a unique physiology or ecology related to their development of unusually large size. The biomass of bacteria varies over more than 10 orders of magnitude, from the 0.2 mum wide nanobacteria to the largest cells of the colorless sulfur bacteria......, Thiomargarita namibiensis, with a diameter of 750 mum. All bacteria, including those that swim around in the environment, obtain their food molecules by molecular diffusion. Only the fastest and largest swimmers known, Thiovulum majus, are able to significantly increase their food supply by motility...... and by actively creating an advective flow through the entire population. Diffusion limitation generally restricts the maximal size of prokaryotic cells and provides a selective advantage for mum-sized cells at the normally low substrate concentrations in the environment. The largest heterotrophic bacteria...

  20. Big bacteria

    DEFF Research Database (Denmark)

    Schulz, HN; Jørgensen, BB

    2001-01-01

    A small number of prokaryotic species have a unique physiology or ecology related to their development of unusually large size. The biomass of bacteria varies over more than 10 orders of magnitude, from the 0.2 mum wide nanobacteria to the largest cells of the colorless sulfur bacteria...... and by actively creating an advective flow through the entire population. Diffusion limitation generally restricts the maximal size of prokaryotic cells and provides a selective advantage for mum-sized cells at the normally low substrate concentrations in the environment. The largest heterotrophic bacteria......, the 80 x 600 mum large Epulopiscium sp. from the gut of tropical fish, are presumably living in a very nutrient-rich medium. Many large bacteria contain numerous inclusions in the cells that reduce the volume of active cytoplasm. The most striking examples of competitive advantage from large cell size...

  1. Magnetic Bacteria.

    Science.gov (United States)

    Nelson, Jane Bray; Nelson, Jim

    1992-01-01

    Describes the history of Richard Blakemore's discovery of magnetotaxic organisms. Discusses possible reasons why the magnetic response in bacteria developed. Proposes research experiments integrating biology and physics in which students investigate problems using cultures of magnetotaxic organisms. (MDH)

  2. The fecal bacteria

    Science.gov (United States)

    Sadowsky, Michael J.; Whitman, Richard L.

    2011-01-01

    The Fecal Bacteria offers a balanced, integrated discussion of fecal bacteria and their presence and ecology in the intestinal tract of mammals, in the environment, and in the food supply. This volume covers their use in examining and assessing water quality in order to offer protection from illnesses related to swimming in or ingesting contaminated water, in addition to discussing their use in engineering considerations of water quality, modeling, monitoring, and regulations. Fecal bacteria are additionally used as indicators of contamination of ready-to-eat foods and fresh produce. The intestinal environment, the microbial community structure of the gut microbiota, and the physiology and genomics of this broad group of microorganisms are explored in the book. With contributions from an internationally recognized group of experts, the book integrates medicine, public health, environmental, and microbiological topics in order to provide a unique, holistic understanding of fecal bacteria. Moreover, it shows how the latest basic science and applied research findings are helping to solve problems and develop effective management strategies. For example, readers will discover how the latest tools and molecular approaches have led to our current understanding of fecal bacteria and enabled us to improve human health and water quality. The Fecal Bacteria is recommended for microbiologists, clinicians, animal scientists, engineers, environmental scientists, food safety experts, water quality managers, and students. It will help them better understand fecal bacteria and use their knowledge to protect human and environmental health. They can also apply many of the techniques and molecular tools discussed in this book to the study of a broad range of microorganisms in a variety of habitats.

  3. Draft Genome of Scalindua rubra, Obtained from the Interface Above the Discovery Deep Brine in the Red Sea, Sheds Light on Potential Salt Adaptation Strategies in Anammox Bacteria

    NARCIS (Netherlands)

    Speth, Daan R.; Lagkouvardos, Ilias; Wang, Yong; Qian, Pei Yuan; Dutilh, Bas E.|info:eu-repo/dai/nl/304546313; Jetten, Mike S M

    2017-01-01

    Several recent studies have indicated that members of the phylum Planctomycetes are abundantly present at the brine-seawater interface (BSI) above multiple brine pools in the Red Sea. Planctomycetes include bacteria capable of anaerobic ammonium oxidation (anammox). Here, we investigated the

  4. Draft Genome of Scalindua rubra, Obtained from the Interface Above the Discovery Deep Brine in the Red Sea, Sheds Light on Potential Salt Adaptation Strategies in Anammox Bacteria

    NARCIS (Netherlands)

    Speth, Daan R.; Lagkouvardos, Ilias; Wang, Yong; Qian, Pei Yuan; Dutilh, Bas E.; Jetten, M.S.M.

    2017-01-01

    Several recent studies have indicated that members of the phylum Planctomycetes are abundantly present at the brine-seawater interface (BSI) above multiple brine pools in the Red Sea. Planctomycetes include bacteria capable of anaerobic ammonium oxidation (anammox). Here, we investigated the

  5. Considering the Specific Impact of Harsh Conditions and Oil Weathering on Diversity, Adaptation, and Activity of Hydrocarbon-Degrading Bacteria in Strategies of Bioremediation of Harsh Oily-Polluted Soils

    Science.gov (United States)

    Al Disi, Zulfa; Jaoua, Samir; Al-Thani, Dhabia; Al-Meer, Saeed

    2017-01-01

    Weathering processes change properties and composition of spilled oil, representing the main reason of failure of bioaugmentation strategies. Our purpose was to investigate the metabolic adaptation of hydrocarbon-degrading bacteria at harsh conditions to be considered to overcome the limitations of bioaugmentation strategies at harsh conditions. Polluted soils, exposed for prolonged periods to weathered oil in harsh soils and weather conditions, were used. Two types of enrichment cultures were employed using 5% and 10% oil or diesel as sole carbon sources with varying the mineral nitrogen sources and C/N ratios. The most effective isolates were obtained based on growth, tolerance to toxicity, and removal efficiency of diesel hydrocarbons. Activities of the newly isolated bacteria, in relation to the microenvironment from where they were isoalted and their interaction with the weathered oil, showed individual specific ability to adapt when exposed to such factors, to acquire metabolic potentialities. Among 39 isolates, ten identified ones by 16S rDNA genes similarities, including special two Pseudomonas isolates and one Citrobacter isolate, showed particularity of shifting hydrocarbon-degrading ability from short chain n-alkanes (n-C12–n-C16) to longer chain n-alkanes (n-C21–n-C25) and vice versa by alternating nitrogen source compositions and C/N ratios. This is shown for the first time. PMID:28243605

  6. Considering the Specific Impact of Harsh Conditions and Oil Weathering on Diversity, Adaptation, and Activity of Hydrocarbon-Degrading Bacteria in Strategies of Bioremediation of Harsh Oily-Polluted Soils

    Directory of Open Access Journals (Sweden)

    Zulfa Al Disi

    2017-01-01

    Full Text Available Weathering processes change properties and composition of spilled oil, representing the main reason of failure of bioaugmentation strategies. Our purpose was to investigate the metabolic adaptation of hydrocarbon-degrading bacteria at harsh conditions to be considered to overcome the limitations of bioaugmentation strategies at harsh conditions. Polluted soils, exposed for prolonged periods to weathered oil in harsh soils and weather conditions, were used. Two types of enrichment cultures were employed using 5% and 10% oil or diesel as sole carbon sources with varying the mineral nitrogen sources and C/N ratios. The most effective isolates were obtained based on growth, tolerance to toxicity, and removal efficiency of diesel hydrocarbons. Activities of the newly isolated bacteria, in relation to the microenvironment from where they were isoalted and their interaction with the weathered oil, showed individual specific ability to adapt when exposed to such factors, to acquire metabolic potentialities. Among 39 isolates, ten identified ones by 16S rDNA genes similarities, including special two Pseudomonas isolates and one Citrobacter isolate, showed particularity of shifting hydrocarbon-degrading ability from short chain n-alkanes (n-C12–n-C16 to longer chain n-alkanes (n-C21–n-C25 and vice versa by alternating nitrogen source compositions and C/N ratios. This is shown for the first time.

  7. Rumen bacteria

    International Nuclear Information System (INIS)

    McSweeney, C.S.; Denman, S.E.; Mackie, R.I.

    2005-01-01

    The rumen is the most extensively studied gut community and is characterized by its high population density, wide diversity and complexity of interactions. This complex, mixed microbial culture is comprised of prokaryote organisms including methane-producing archaebacteria, eukaryote organisms, such as ciliate and flagellate protozoa, anaerobic phycomycete fungi and bacteriophage. Bacteria are predominant (up to 10 11 viable cells per g comprising 200 species) but a variety of ciliate protozoa occur widely (10 4 -10 6 /g distributed over 25 genera). The anaerobic fungi are also widely distributed (zoospore population densities of 10 2 -10 4 /g distributed over 5 genera). The occurrence of bacteriophage is well documented (10 7 -10 9 particles/g). This section focuses primarily on the widely used methods for the cultivation and the enumeration of rumen microbes, especially bacteria, which grow under anaerobic conditions. Methods that can be used to measure hydrolytic enzymes (cellulases, xylanases, amylases and proteinases) are also described, along with cell harvesting and fractionation procedures. Brief reference is also made to fungi and protozoa, but detailed explanations for culturing and enumerating these microbes is presented in Chapters 2.4 and 2.5

  8. Acanthamoeba feature a unique backpacking strategy to trap and feed on Listeria monocytogenes and other motile bacteria

    DEFF Research Database (Denmark)

    Doyscher, Dominik; Fieseler, Lars; Dons, Lone Elisabet

    2013-01-01

    Despite its prominent role as an intracellular human pathogen, Listeria monocytogenes normally features a saprophytic lifestyle, and shares many environmental habitats with predatory protozoa. Earlier studies claimed that Acanthamoeba may act as environmental reservoirs for L.?monocytogenes, wher......Despite its prominent role as an intracellular human pathogen, Listeria monocytogenes normally features a saprophytic lifestyle, and shares many environmental habitats with predatory protozoa. Earlier studies claimed that Acanthamoeba may act as environmental reservoirs for L.......?monocytogenes, whereas others failed to confirm this hypothesis. Our findings support the latter and provide clear evidence that L.?monocytogenes is unable to persist in Acanthamoeba castellanii and A.?polyphaga. Instead, external Listeria cells are rapidly immobilized on the surface of Acanthamoeba trophozoites......-lapse microscopy revealed that shortly after the bacteria are collected, the amoeba can change direction of movement, phagocytose the backpack and continue to repeat the process. The phenomenon was also observed with avirulent L.?monocytogenes mutants, non-pathogenic Listeria, and other motile bacteria, indicating...

  9. Inoculating Helianthus annuus (sunflower) grown in zinc and cadmium contaminated soils with plant growth promoting bacteria--effects on phytoremediation strategies.

    Science.gov (United States)

    Marques, Ana P G C; Moreira, Helena; Franco, Albina R; Rangel, António O S S; Castro, Paula M L

    2013-06-01

    Plant growth promoting bacteria (PGPR) may help reducing the toxicity of heavy metals to plants in polluted environments. In this work the effects of inoculating metal resistant and plant growth promoting bacterial strains on the growth of Helianthus annuus grown in Zn and Cd spiked soils were assessed. The PGPR strains Ralstonia eutropha (B1) and Chrysiobacterium humi (B2) reduced losses of weight in metal exposed plants and induced changes in metal bioaccumulation and bioconcentration - with strain B2 decreasing up to 67% Zn accumulation and by 20% Zn bioconcentration factor (BCF) in the shoots, up to 64% Zn uptake and 38% Zn BCF in the roots, and up to 27% Cd uptake and 27% Cd BCF in plant roots. The impact of inoculation on the bacterial communities in the rhizosphere of the plant was also assessed. Bacterial community diversity decreased with increasing levels of metal contamination in the soil, but in rhizosphere soil of plants inoculated with the PGPR strains, a higher bacterial diversity was kept throughout the experimental period. Inoculation of sunflower, particularly with C. humi (B2), appears to be an effective way of enhancing the short term stabilization potential of the plant in metal contaminated land, lowering losses in plant biomass and decreasing aboveground tissue contamination. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Bleach vs. Bacteria

    Science.gov (United States)

    ... Articles | Inside Life Science Home Page Bleach vs. Bacteria By Sharon Reynolds Posted April 2, 2014 Your ... hypochlorous acid to help kill invading microbes, including bacteria. Researchers funded by the National Institutes of Health ...

  11. Bacteria and lignin degradation

    Institute of Scientific and Technical Information of China (English)

    Jing LI; Hongli YUAN; Jinshui YANG

    2009-01-01

    Lignin is both the most abundant aromatic (phenolic) polymer and the second most abundant raw material.It is degraded and modified by bacteria in the natural world,and bacteria seem to play a leading role in decomposing lignin in aquatic ecosystems.Lignin-degrading bacteria approach the polymer by mechanisms such as tunneling,erosion,and cavitation.With the advantages of immense environmental adaptability and biochemical versatility,bacteria deserve to be studied for their ligninolytic potential.

  12. Optimal strategy for competence differentiation in bacteria.

    Directory of Open Access Journals (Sweden)

    C Scott Wylie

    2010-09-01

    Full Text Available A phylogenetically diverse subset of bacterial species are naturally competent for transformation by DNA. Transformation entails recombination of genes between different lineages, representing a form of bacterial sex that increases standing genetic variation. We first assess whether homologous recombination by transformation is favored by evolution. Using stochastic population genetic computer simulations in which beneficial and deleterious mutations occur at many loci throughout the whole genome, we find that transformation can increase both the rate of adaptive evolution and the equilibrium level of fitness. Secondly, motivated by experimental observations of Bacillus subtilis, we assume that competence additionally entails a weak persister phenotype, i.e., the rates of birth and death are reduced for these cells. Consequently, persisters evolve more slowly than non-persisters. We show via simulation that strains which stochastically switch into and out of the competent phenotype are evolutionarily favored over strains that express only a single phenotype. Our model's simplicity enables us to derive and numerically solve a system of finite- deterministic equations that describe the evolutionary dynamics. The observed tradeoff between the benefit of recombination and the cost of persistence may explain the previously mysterious observation that only a fractional subpopulation of B. subtilis cells express competence. More generally, this work demonstrates that population genetic forces can give rise to phenotypic diversity even in an unchanging and homogeneous environment.

  13. Genomics of Probiotic Bacteria

    Science.gov (United States)

    O'Flaherty, Sarah; Goh, Yong Jun; Klaenhammer, Todd R.

    Probiotic bacteria from the Lactobacillus and Bifidobacterium species belong to the Firmicutes and the Actinobacteria phylum, respectively. Lactobacilli are members of the lactic acid bacteria (LAB) group, a broadly defined family of microorganisms that ferment various hexoses into primarily lactic acid. Lactobacilli are typically low G + C gram-positive species which are phylogenetically diverse, with over 100 species documented to date. Bifidobacteria are heterofermentative, high G + C content bacteria with about 30 species of bifidobacteria described to date.

  14. [Unique properties of highly radioresistant bacteria].

    Science.gov (United States)

    Romanovskaia, V A; Rokitko, P V; Malashenko, Iu R

    2000-01-01

    In connection with the Chernobyl Nuclear Power Plant (ChNPP) accident and the negative ecological after-effects for biota in this zone the interest has arisen to radioresistant bacteria, as to the most dynamic model of the given ecosystem, and to mechanisms which provide resistance of bacteria to ionizing radiation. The analysis of published data has shown that the radioresistant bacteria are not interrelated taxonomically and phylogenetically. The extreme radioresistant bacteria are represented by the Deinococcus species, which form a group phylogenetically close to the line Thermus-Meiothermus. Other radioresistant bacteria are the representatives of the genera Rubrobacter, Methylobacterium, Kocuria, Bacillus and some archebacteria. Data on natural habitats, of radioresistant bacteria are not numerous. In a number of cases it is difficult to distinguish their natural habitats, as they were isolated from the samples which were previously exposed to X-ray or gamma-irradiation, or from the ecosystems with the naturally raised radioactivity. To understand the strategy of survival of radioresistant bacteria, we briefly reviewed the mechanism of action of various species of radiation on cells and macromolecules; physiological signs of the cell damage caused by radiation; mechanisms eliminating (repairing) these damages. More details on mechanisms of the DNA repair in D. radiodurans are described. The extreme resistance of D. radiodurans to the DNA damaging factors is defined by 1) repair mechanisms which fundamentally differ from those in other procaryotes; 2) ability to increase the efficiency of a standard set of the DNA repairing proteins. Literary and own data on the effect of radiation on survival of various groups of bacteria in natural ecosystems are summarized. The ecological consequences of the ChNPP accident for soil bacteria in this region were estimated. The reduction of the number of soil bacteria and recession of microbial diversity under the effect of

  15. How honey kills bacteria

    NARCIS (Netherlands)

    Kwakman, Paulus H. S.; te Velde, Anje A.; de Boer, Leonie; Speijer, Dave; Vandenbroucke-Grauls, Christina M. J. E.; Zaat, Sebastian A. J.

    2010-01-01

    With the rise in prevalence of antibiotic-resistant bacteria, honey is increasingly valued for its antibacterial activity. To characterize all bactericidal factors in a medical-grade honey, we used a novel approach of successive neutralization of individual honey bactericidal factors. All bacteria

  16. Hydrocarbon degradation potentials of bacteria isolated from spent ...

    African Journals Online (AJOL)

    Hydrocarbon degradation potentials of bacteria isolated from spent lubricating oil contaminated soil. ... This study has shown that resident bacteria strains in lubricating oil contaminated soils have potential application in the bioremediation of oil polluted sites and enhance the possibility of developing models and strategies ...

  17. Mathematical studies on nosocomial spread of antibiotic-resistant bacteria

    NARCIS (Netherlands)

    Gurieva, T.V.

    2017-01-01

    Infections with antibiotic-resistant bacteria are a worldwide problem in hospitals and their rates remain high in many countries despite efforts to reduce the rates. Infection prevention is complicated by asymptomatic carriers. Using mathematical modelling, different intervention strategies were

  18. Extracellular communication in bacteria

    DEFF Research Database (Denmark)

    Chhabra, S.R.; Philipp, B.; Eberl, L.

    2005-01-01

    molecules, in different Gram-positive and Gram-negative bacteria they control pathogenicity, secondary metabolite production, biofilm differentiation, DNA transfer and bioluminescence. The development of biosensors for the detection of these signal molecules has greatly facilitated their subsequent chemical...

  19. Do Bacteria Age?

    Indian Academy of Sciences (India)

    Bacteria are thought to be examples of organisms that do not age. They divide by .... carry genetic material to the next generation through the process of reproduction; they are also .... molecules, and modified proteins. This report revealed that ...

  20. Social Behaviour in Bacteria

    Indian Academy of Sciences (India)

    Administrator

    the recipient. • Social behaviours can be categorized according to the fitness ... is actually the flagella of symbiotic spirochete bacteria that helps it to swim around .... Normal population. Responsive switching. (Environmental stress). Stochastic.

  1. [Darwin and bacteria].

    Science.gov (United States)

    Ledermann D, Walter

    2009-02-01

    As in 2009 the scientific world celebrates two hundreds years from the birthday of Charles Darwin and one hundred and fifty from the publication of The Origin of Species, an analysis of his complete work is performed, looking for any mention of bacteria. But it seems that the great naturahst never took knowledge about its existence, something rather improbable in a time when the discovery of bacteria shook the medical world, or he deliberately ignored them, not finding a place for such microscopic beings into his theory of evolution. But the bacteria badly affected his familiar life, killing scarlet fever one of his children and worsening to death the evolution of tuberculosis of his favourite Annie. Darwin himself could suffer the sickness of Chagas, whose etiological agent has a similar level to bacteria in the scale of evolution.

  2. Lipopolysaccharides in diazotrophic bacteria

    OpenAIRE

    Serrato, Rodrigo V.

    2014-01-01

    Biological nitrogen fixation (BNF) is a process in which the atmospheric nitrogen (N2) is transformed into ammonia (NH3) by a select group of nitrogen-fixing organisms, or diazotrophic bacteria. In order to furnish the biologically useful nitrogen to plants, these bacteria must be in constant molecular communication with their host plants. Some of these molecular plant-microbe interactions are very specific, resulting in a symbiotic relationship between the diazotroph and the host. Others are...

  3. Lipopolysaccharides in diazotrophic bacteria.

    Science.gov (United States)

    Serrato, Rodrigo V

    2014-01-01

    Biological nitrogen fixation (BNF) is a process in which the atmospheric nitrogen (N2) is transformed into ammonia (NH3) by a select group of nitrogen-fixing organisms, or diazotrophic bacteria. In order to furnish the biologically useful nitrogen to plants, these bacteria must be in constant molecular communication with their host plants. Some of these molecular plant-microbe interactions are very specific, resulting in a symbiotic relationship between the diazotroph and the host. Others are found between associative diazotrophs and plants, resulting in plant infection and colonization of internal tissues. Independent of the type of ecological interaction, glycans, and glycoconjugates produced by these bacteria play an important role in the molecular communication prior and during colonization. Even though exopolysaccharides (EPS) and lipochitooligosaccharides (LCO) produced by diazotrophic bacteria and released onto the environment have their importance in the microbe-plant interaction, it is the lipopolysaccharides (LPS), anchored on the external membrane of these bacteria, that mediates the direct contact of the diazotroph with the host cells. These molecules are extremely variable among the several species of nitrogen fixing-bacteria, and there are evidences of the mechanisms of infection being closely related to their structure.

  4. Deployable micro-traps to sequester motile bacteria

    Science.gov (United States)

    di Giacomo, Raffaele; Krödel, Sebastian; Maresca, Bruno; Benzoni, Patrizia; Rusconi, Roberto; Stocker, Roman; Daraio, Chiara

    2017-04-01

    The development of strategies to reduce the load of unwanted bacteria is a fundamental challenge in industrial processing, environmental sciences and medical applications. Here, we report a new method to sequester motile bacteria from a liquid, based on passive, deployable micro-traps that confine bacteria using micro-funnels that open into trapping chambers. Even in low concentrations, micro-traps afford a 70% reduction in the amount of bacteria in a liquid sample, with a potential to reach >90% as shown by modelling improved geometries. This work introduces a new approach to contain the growth of bacteria without chemical means, an advantage of particular importance given the alarming growth of pan-drug-resistant bacteria.

  5. 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.

  6. Mycorrhiza helper bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Deveau, Aurelie [French National Insitute for Agricultural Research (INRA); Labbe, Jessy [ORNL

    2016-10-01

    This chapter focuses on the Mycorrhiza Helper Bacteria (MHB), a generic name given to bacteria which stimulate the formation of mycorrhizal symbiosis. By extension, some bacterial strains that positively impact the functioning of mycorrhizal symbiosis are also called MHB. These bacteria have applicative interests, as they indirectly improve the health and growth of tree seedlings. MHB are not restricted to a specific type of ecosystem, but are rather generalist in the way that they associate with both herbaceous and woody mycorrhizal plants from boreal, temperate, arid and tropical ecosystems. However, understanding the molecular mechanisms and their specificities will help us to know more about the ecology of the MHB. The process of acquisition varies between fungal species; while ectomycorrhizal fungi most probably recurrently acquire them from the environment, the association between bacterial endosymbionts and Glomeromycota probably dates back to very ancient times, and has since been vertically transmitted.

  7. Communication among Oral Bacteria

    Science.gov (United States)

    Kolenbrander, Paul E.; Andersen, Roxanna N.; Blehert, David S.; Egland, Paul G.; Foster, Jamie S.; Palmer, Robert J.

    2002-01-01

    Human oral bacteria interact with their environment by attaching to surfaces and establishing mixed-species communities. As each bacterial cell attaches, it forms a new surface to which other cells can adhere. Adherence and community development are spatiotemporal; such order requires communication. The discovery of soluble signals, such as autoinducer-2, that may be exchanged within multispecies communities to convey information between organisms has emerged as a new research direction. Direct-contact signals, such as adhesins and receptors, that elicit changes in gene expression after cell-cell contact and biofilm growth are also an active research area. Considering that the majority of oral bacteria are organized in dense three-dimensional biofilms on teeth, confocal microscopy and fluorescently labeled probes provide valuable approaches for investigating the architecture of these organized communities in situ. Oral biofilms are readily accessible to microbiologists and are excellent model systems for studies of microbial communication. One attractive model system is a saliva-coated flowcell with oral bacterial biofilms growing on saliva as the sole nutrient source; an intergeneric mutualism is discussed. Several oral bacterial species are amenable to genetic manipulation for molecular characterization of communication both among bacteria and between bacteria and the host. A successful search for genes critical for mixed-species community organization will be accomplished only when it is conducted with mixed-species communities. PMID:12209001

  8. PATHOGENICITY OF BIOFILM BACTERIA

    Science.gov (United States)

    There is a paucity of information concerning any link between the microorganisms commonly found in biofilms of drinking water systems and their impacts on human health. For bacteria, culture-based techniques detect only a limited number of the total microorganisms associated wit...

  9. Bacteria-surface interactions.

    Science.gov (United States)

    Tuson, Hannah H; Weibel, Douglas B

    2013-05-14

    The interaction of bacteria with surfaces has important implications in a range of areas, including bioenergy, biofouling, biofilm formation, and the infection of plants and animals. Many of the interactions of bacteria with surfaces produce changes in the expression of genes that influence cell morphology and behavior, including genes essential for motility and surface attachment. Despite the attention that these phenotypes have garnered, the bacterial systems used for sensing and responding to surfaces are still not well understood. An understanding of these mechanisms will guide the development of new classes of materials that inhibit and promote cell growth, and complement studies of the physiology of bacteria in contact with surfaces. Recent studies from a range of fields in science and engineering are poised to guide future investigations in this area. This review summarizes recent studies on bacteria-surface interactions, discusses mechanisms of surface sensing and consequences of cell attachment, provides an overview of surfaces that have been used in bacterial studies, and highlights unanswered questions in this field.

  10. Antifreeze Proteins of Bacteria

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 12; Issue 12. Antifreeze Proteins of Bacteria. M K Chattopadhyay. General Article Volume 12 Issue 12 December 2007 pp 25-30. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/012/12/0025-0030 ...

  11. Respective impact of implementation of prevention strategies, colonization with multiresistant bacteria and antimicrobial use on the risk of early- and late-onset VAP: An analysis of the OUTCOMEREA network

    OpenAIRE

    Ibn Saied, Wafa; Souweine, Bertrand; Garrouste-Orgeas, Maité; Ruckly, Stéphane; Darmon, Michael; Bailly, Sébastien; Cohen, Yves; Azoulay, Elie; Schwebel, Carole; Radjou, Aguila; Kallel, Hatem; Adrie, Christophe; Dumenil, Anne-Sylvie; Argaud, Laurent; Marcotte, Guillaume

    2017-01-01

    International audience; Rationale: The impact of prevention strategies and risk factors for early-onset (EOP) versus late-onset (LOP) ventilator -associated pneumonia (VAP) are still debated.Objectives: To evaluate, in a multicenter cohort, the risk factors for EOP and LOP, as the evolution of prevention strategies.Methods: 7,784 patients with mechanical ventilation (MV) for at least 48 hours were selected into the multicenter prospective OUTCOMEREA database (1997-2016). VAP occurring between...

  12. The friendly bacteria within us Commensal bacteria of the intestine ...

    Indian Academy of Sciences (India)

    Balance of bacterial species in the gut · Immunosensory detection of intestinal bacteria · Pathogenic bacteria release interleukin-8 from HT-29 cells · Lactobacillus GG prevents the IL-8 release in response to pathogens · Effect of probiotic bacteria on chemokine response of epithelia to pathogens · PCR array studies in colon ...

  13. Manufacture of Probiotic Bacteria

    Science.gov (United States)

    Muller, J. A.; Ross, R. P.; Fitzgerald, G. F.; Stanton, C.

    Lactic acid bacteria (LAB) have been used for many years as natural biopreservatives in fermented foods. A small group of LAB are also believed to have beneficial health effects on the host, so called probiotic bacteria. Probiotics have emerged from the niche industry from Asia into European and American markets. Functional foods are one of the fastest growing markets today, with estimated growth to 20 billion dollars worldwide by 2010 (GIA, 2008). The increasing demand for probiotics and the new food markets where probiotics are introduced, challenges the industry to produce high quantities of probiotic cultures in a viable and stable form. Dried concentrated probiotic cultures are the most convenient form for incorporation into functional foods, given the ease of storage, handling and transport, especially for shelf-stable functional products. This chapter will discuss various aspects of the challenges associated with the manufacturing of probiotic cultures.

  14. Pepsin homologues in bacteria

    Directory of Open Access Journals (Sweden)

    Bateman Alex

    2009-09-01

    Full Text Available Abstract Background Peptidase family A1, to which pepsin belongs, had been assumed to be restricted to eukaryotes. The tertiary structure of pepsin shows two lobes with similar folds and it has been suggested that the gene has arisen from an ancient duplication and fusion event. The only sequence similarity between the lobes is restricted to the motif around the active site aspartate and a hydrophobic-hydrophobic-Gly motif. Together, these contribute to an essential structural feature known as a psi-loop. There is one such psi-loop in each lobe, and so each lobe presents an active Asp. The human immunodeficiency virus peptidase, retropepsin, from peptidase family A2 also has a similar fold but consists of one lobe only and has to dimerize to be active. All known members of family A1 show the bilobed structure, but it is unclear if the ancestor of family A1 was similar to an A2 peptidase, or if the ancestral retropepsin was derived from a half-pepsin gene. The presence of a pepsin homologue in a prokaryote might give insights into the evolution of the pepsin family. Results Homologues of the aspartic peptidase pepsin have been found in the completed genomic sequences from seven species of bacteria. The bacterial homologues, unlike those from eukaryotes, do not possess signal peptides, and would therefore be intracellular acting at neutral pH. The bacterial homologues have Thr218 replaced by Asp, a change which in renin has been shown to confer activity at neutral pH. No pepsin homologues could be detected in any archaean genome. Conclusion The peptidase family A1 is found in some species of bacteria as well as eukaryotes. The bacterial homologues fall into two groups, one from oceanic bacteria and one from plant symbionts. The bacterial homologues are all predicted to be intracellular proteins, unlike the eukaryotic enzymes. The bacterial homologues are bilobed like pepsin, implying that if no horizontal gene transfer has occurred the duplication

  15. Incorporation of therapeutically modified bacteria into gut microbiota inhibits obesity.

    Science.gov (United States)

    Chen, Zhongyi; Guo, Lilu; Zhang, Yongqin; Walzem, Rosemary L; Pendergast, Julie S; Printz, Richard L; Morris, Lindsey C; Matafonova, Elena; Stien, Xavier; Kang, Li; Coulon, Denis; McGuinness, Owen P; Niswender, Kevin D; Davies, Sean S

    2014-08-01

    Metabolic disorders, including obesity, diabetes, and cardiovascular disease, are widespread in Westernized nations. Gut microbiota composition is a contributing factor to the susceptibility of an individual to the development of these disorders; therefore, altering a person's microbiota may ameliorate disease. One potential microbiome-altering strategy is the incorporation of modified bacteria that express therapeutic factors into the gut microbiota. For example, N-acylphosphatidylethanolamines (NAPEs) are precursors to the N-acylethanolamide (NAE) family of lipids, which are synthesized in the small intestine in response to feeding and reduce food intake and obesity. Here, we demonstrated that administration of engineered NAPE-expressing E. coli Nissle 1917 bacteria in drinking water for 8 weeks reduced the levels of obesity in mice fed a high-fat diet. Mice that received modified bacteria had dramatically lower food intake, adiposity, insulin resistance, and hepatosteatosis compared with mice receiving standard water or control bacteria. The protective effects conferred by NAPE-expressing bacteria persisted for at least 4 weeks after their removal from the drinking water. Moreover, administration of NAPE-expressing bacteria to TallyHo mice, a polygenic mouse model of obesity, inhibited weight gain. Our results demonstrate that incorporation of appropriately modified bacteria into the gut microbiota has potential as an effective strategy to inhibit the development of metabolic disorders.

  16. The effects of bacteria on crystalline rock

    International Nuclear Information System (INIS)

    Brown, D.A.

    1994-01-01

    Many reactions involving inorganic minerals at water-rock interfaces have now been recognized to be bacterially mediated; these reactions could have a significant effect in the excavation of vaults for toxic and radioactive waste disposal. To investigate the role that bacteria play in the natural aqueous environment of crystalline rock the microbial growth factors of nutrition, energy and environment are described. Microbial activity has been investigated in Atomic Energy of Canada's Underground Research Laboratory (URL), situated in the Archean granitic Lac du Bonnet Batholith, Winnipeg, Manitoba. Faults, initiated in the Early Proterozoic, and later-formed fractures, provide ground-water pathways. Planktonic bacteria, free-swimming in the groundwater, have been observed in over 100 underground borehole samples. The number of bacteria varied from 10 3 to 10 5 mL -1 and appeared to decrease with depth and with increased salinity of the water. However, in the natural environment of deep (100-500 m) crystalline rocks, where nutrition is limited, formation of biofilms by sessile bacteria is a successful survival strategy. Natural biofilms at the URL and biofilms grown in bioreactors have been studied. The biofilms can accumulate different elements, depending upon the local environment. Precipitates of iron have been found in all the biofilms studied, where they are either passively accumulated or utilized as an energy source. Within the biofilm active and extensive biogeochemical immobilization of dissolved elements is controlled by distinct bacterial activities which are sufficiently discrete for hematite and siderite to be precipitated in close proximity

  17. Visualizing aquatic bacteria by light and transmission electron microscopy.

    Science.gov (United States)

    Silva, Thiago P; Noyma, Natália P; Duque, Thabata L A; Gamalier, Juliana P; Vidal, Luciana O; Lobão, Lúcia M; Chiarini-Garcia, Hélio; Roland, Fábio; Melo, Rossana C N

    2014-01-01

    The understanding of the functional role of aquatic bacteria in microbial food webs is largely dependent on methods applied to the direct visualization and enumeration of these organisms. While the ultrastructure of aquatic bacteria is still poorly known, routine observation of aquatic bacteria by light microscopy requires staining with fluorochromes, followed by filtration and direct counting on filter surfaces. Here, we used a new strategy to visualize and enumerate aquatic bacteria by light microscopy. By spinning water samples from varied tropical ecosystems in a cytocentrifuge, we found that bacteria firmly adhere to regular slides, can be stained by fluorochoromes with no background formation and fast enumerated. Significant correlations were found between the cytocentrifugation and filter-based methods. Moreover, preparations through cytocentrifugation were more adequate for bacterial viability evaluation than filter-based preparations. Transmission electron microscopic analyses revealed a morphological diversity of bacteria with different internal and external structures, such as large variation in the cell envelope and capsule thickness, and presence or not of thylakoid membranes. Our results demonstrate that aquatic bacteria represent an ultrastructurally diverse population and open avenues for easy handling/quantification and better visualization of bacteria by light microscopy without the need of filter membranes.

  18. Plant growth-promoting bacteria: mechanisms and applications.

    Science.gov (United States)

    Glick, Bernard R

    2012-01-01

    The worldwide increases in both environmental damage and human population pressure have the unfortunate consequence that global food production may soon become insufficient to feed all of the world's people. It is therefore essential that agricultural productivity be significantly increased within the next few decades. To this end, agricultural practice is moving toward a more sustainable and environmentally friendly approach. This includes both the increasing use of transgenic plants and plant growth-promoting bacteria as a part of mainstream agricultural practice. Here, a number of the mechanisms utilized by plant growth-promoting bacteria are discussed and considered. It is envisioned that in the not too distant future, plant growth-promoting bacteria (PGPB) will begin to replace the use of chemicals in agriculture, horticulture, silviculture, and environmental cleanup strategies. While there may not be one simple strategy that can effectively promote the growth of all plants under all conditions, some of the strategies that are discussed already show great promise.

  19. Functional amyloids in bacteria.

    Science.gov (United States)

    Romero, Diego; Kolter, Roberto

    2014-06-01

    The term amyloidosis is used to refer to a family of pathologies altering the homeostasis of human organs. Despite having a name that alludes to starch content, the amyloid accumulations are made up of proteins that polymerize as long and rigid fibers. Amyloid proteins vary widely with respect to their amino acid sequences but they share similarities in their quaternary structure; the amyloid fibers are enriched in β-sheets arranged perpendicular to the axis of the fiber. This structural feature provides great robustness, remarkable stability, and insolubility. In addition, amyloid proteins specifically stain with certain dyes such as Congo red and thioflavin-T. The aggregation into amyloid fibers, however, it is not restricted to pathogenic processes, rather it seems to be widely distributed among proteins and polypeptides. Amyloid fibers are present in insects, fungi and bacteria, and they are important in maintaining the homeostasis of the organism. Such findings have motivated the use of the term "functional amyloid" to differentiate these amyloid proteins from their toxic siblings. This review focuses on systems that have evolved in bacteria that control the expression and assembly of amyloid proteins on cell surfaces, such that the robustness of amyloid proteins are used towards a beneficial end. Copyright© by the Spanish Society for Microbiology and Institute for Catalan Studies.

  20. Temperate and lytic bacteriophages programmed to sensitize and kill antibiotic-resistant bacteria.

    Science.gov (United States)

    Yosef, Ido; Manor, Miriam; Kiro, Ruth; Qimron, Udi

    2015-06-09

    The increasing threat of pathogen resistance to antibiotics requires the development of novel antimicrobial strategies. Here we present a proof of concept for a genetic strategy that aims to sensitize bacteria to antibiotics and selectively kill antibiotic-resistant bacteria. We use temperate phages to deliver a functional clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated (Cas) system into the genome of antibiotic-resistant bacteria. The delivered CRISPR-Cas system destroys both antibiotic resistance-conferring plasmids and genetically modified lytic phages. This linkage between antibiotic sensitization and protection from lytic phages is a key feature of the strategy. It allows programming of lytic phages to kill only antibiotic-resistant bacteria while protecting antibiotic-sensitized bacteria. Phages designed according to this strategy may be used on hospital surfaces and hand sanitizers to facilitate replacement of antibiotic-resistant pathogens with sensitive ones.

  1. Respective impact of implementation of prevention strategies, colonization with multiresistant bacteria and antimicrobial use on the risk of early- and late-onset VAP: An analysis of the OUTCOMEREA network.

    Directory of Open Access Journals (Sweden)

    Wafa Ibn Saied

    Full Text Available The impact of prevention strategies and risk factors for early-onset (EOP versus late-onset (LOP ventilator-associated pneumonia (VAP are still debated.To evaluate, in a multicenter cohort, the risk factors for EOP and LOP, as the evolution of prevention strategies.7,784 patients with mechanical ventilation (MV for at least 48 hours were selected into the multicenter prospective OUTCOMEREA database (1997-2016. VAP occurring between the 3rd and 6th day of MV defined EOP, while those occurring after defined LOPs. We used a Fine and Gray subdistribution model to take the successful extubation into account as a competing event.Overall, 1,234 included patients developed VAP (EOP: 445 (36%; LOP: 789 (64%. Male gender was a risk factor for both EOP and LOP. Factors specifically associated with EOP were admission for respiratory distress, previous colonization with multidrug-resistant Pseudomonas aeruginosa, chest tube and enteral feeding within the first 2 days of MV. Antimicrobials administrated within the first 2 days of MV were all protective of EOP. ICU admission for COPD exacerbation or pneumonia were early risk factors for LOP, while imidazole and vancomycin use within the first 2 days of MV were protective factors. Late risk factors (between the 3rd and the 6th day of MV were the intra-hospital transport, PAO2-FIO2<200 mmHg, vasopressor use, and known colonization with methicillin-resistant Staphylococcus aureus. Among the antimicrobials administered between the 3rd and the 6th day, fluoroquinolones were the solely protective one.Contrarily to LOP, the risk of EOP decreased across the study time periods, concomitantly with an increase in the compliance with bundle of prevention measures.VAP risk factors are mostly different according to the pneumonia time of onset, which should lead to differentiated prevention strategies.

  2. Cable Bacteria in Freshwater Sediments

    DEFF Research Database (Denmark)

    Risgaard-Petersen, Nils; Kristiansen, Michael; Frederiksen, Rasmus

    2015-01-01

    In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable...... bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the freshwater stream Giber Å, Denmark, was incubated in the laboratory. After 2 weeks, pH signatures...... marine cable bacteria, with the genus Desulfobulbus as the closest cultured lineage. The results of the present study indicate that electric currents mediated by cable bacteria could be important for the biogeochemistry in many more environments than anticipated thus far and suggest a common evolutionary...

  3. Immunomodulatory properties of probiotic bacteria

    DEFF Research Database (Denmark)

    Fink, Lisbeth Nielsen

    2007-01-01

    Certain lactic acid bacteria (LAB) are part of the commensal intestinal flora and considered beneficial for health, as they compete with pathogens for adhesion sites in the intestine and ferment otherwise indigestible compounds. Another important property of these so-called probiotic bacteria...... with bacteria, and the cytokine pattern induced by specific bacteria resembled the pattern induced in MoDC, except for TNF-alpha and IL-6, which were induced in response to different bacteria in blood DC/monocytes and monocyte-derived DC. Autologous NK cells produced IFN-gamma when cultured with blood DC......, monocytes and monocyte-derived DC and IL-12-inducing bacteria, whereas only DC induced IFN-gamma production in allogeneic T cells. In vitro-generated DC is a commonly used model of tissue DC, but they differ in certain aspects from intestinal DC, which are in direct contact with the intestinal microbiota...

  4. Radiation-resistant asporogenic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Yano, K [Tokyo Univ. (Japan). Faculty of Agriculture

    1975-09-01

    This paper reports the biological and ecological examinations on the radiation-resistant asporogenic bacteria (mainly concerning Micrococcus radiodurans). Radiation-resistant asporogenic bacteria were isolated from the irradiated areas of the natural world as well as from the general areas and from the Rn waters in the Misasa hot spring. The acquiring of the tolerance to radiation in bacteria was also examined. In addition, the future problems of microbiological treatment with irradiation were mentioned.

  5. Radiation-resistant asporogenic bacteria

    International Nuclear Information System (INIS)

    Yano, Keiji

    1975-01-01

    This paper reports the biological and ecological examinations on the radiation-resistant asporogenic bacteria (mainly concerning Micrococcus radiodurans). Radiation-resistant asporogenic bacteria were isolated from the irradiated areas of the natural world as well as from the general areas and from the Rn waters in the Misasa hot spring. The acquiring of the tolerance to radiation in bacteria was also examined. In addition, the future problems of microbiological treatment with irradiation were mentioned. (Tsukamoto, Y.)

  6. Acoustofluidic bacteria separation

    International Nuclear Information System (INIS)

    Li, Sixing; Huang, Tony Jun; Ma, Fen; Zeng, Xiangqun; Bachman, Hunter; Cameron, Craig E

    2017-01-01

    Bacterial separation from human blood samples can help with the identification of pathogenic bacteria for sepsis diagnosis. In this work, we report an acoustofluidic device for label-free bacterial separation from human blood samples. In particular, we exploit the acoustic radiation force generated from a tilted-angle standing surface acoustic wave (taSSAW) field to separate Escherichia coli from human blood cells based on their size difference. Flow cytometry analysis of the E. coli separated from red blood cells shows a purity of more than 96%. Moreover, the label-free electrochemical detection of the separated E. coli displays reduced non-specific signals due to the removal of blood cells. Our acoustofluidic bacterial separation platform has advantages such as label-free separation, high biocompatibility, flexibility, low cost, miniaturization, automation, and ease of in-line integration. The platform can be incorporated with an on-chip sensor to realize a point-of-care sepsis diagnostic device. (paper)

  7. Acoustofluidic bacteria separation

    Science.gov (United States)

    Li, Sixing; Ma, Fen; Bachman, Hunter; Cameron, Craig E.; Zeng, Xiangqun; Huang, Tony Jun

    2017-01-01

    Bacterial separation from human blood samples can help with the identification of pathogenic bacteria for sepsis diagnosis. In this work, we report an acoustofluidic device for label-free bacterial separation from human blood samples. In particular, we exploit the acoustic radiation force generated from a tilted-angle standing surface acoustic wave (taSSAW) field to separate Escherichia coli from human blood cells based on their size difference. Flow cytometry analysis of the E. coli separated from red blood cells shows a purity of more than 96%. Moreover, the label-free electrochemical detection of the separated E. coli displays reduced non-specific signals due to the removal of blood cells. Our acoustofluidic bacterial separation platform has advantages such as label-free separation, high biocompatibility, flexibility, low cost, miniaturization, automation, and ease of in-line integration. The platform can be incorporated with an on-chip sensor to realize a point-of-care sepsis diagnostic device.

  8. Bacteria, phages and septicemia.

    Directory of Open Access Journals (Sweden)

    Ausra Gaidelyte

    Full Text Available The use of phages is an attractive option to battle antibiotic resistant bacteria in certain bacterial infections, but the role of phage ecology in bacterial infections is obscure. Here we surveyed the phage ecology in septicemia, the most severe type of bacterial infection. We observed that the majority of the bacterial isolates from septicemia patients spontaneously secreted phages active against other isolates of the same bacterial strain, but not to the strain causing the disease. Such phages were also detected in the initial blood cultures, indicating that phages are circulating in the blood at the onset of sepsis. The fact that most of the septicemic bacterial isolates carry functional prophages suggests an active role of phages in bacterial infections. Apparently, prophages present in sepsis-causing bacterial clones play a role in clonal selection during bacterial invasion.

  9. Interactions between the microbiota and pathogenic bacteria in the gut.

    Science.gov (United States)

    Bäumler, Andreas J; Sperandio, Vanessa

    2016-07-07

    The microbiome has an important role in human health. Changes in the microbiota can confer resistance to or promote infection by pathogenic bacteria. Antibiotics have a profound impact on the microbiota that alters the nutritional landscape of the gut and can lead to the expansion of pathogenic populations. Pathogenic bacteria exploit microbiota-derived sources of carbon and nitrogen as nutrients and regulatory signals to promote their own growth and virulence. By eliciting inflammation, these bacteria alter the intestinal environment and use unique systems for respiration and metal acquisition to drive their expansion. Unravelling the interactions between the microbiota, the host and pathogenic bacteria will produce strategies for manipulating the microbiota against infectious diseases.

  10. Vibrio bacteria in raw oysters: managing risks to human health.

    Science.gov (United States)

    Froelich, Brett A; Noble, Rachel T

    2016-03-05

    The human-pathogenic marine bacteria Vibrio vulnificus and V. parahaemolyticus are strongly correlated with water temperature, with concentrations increasing as waters warm seasonally. Both of these bacteria can be concentrated in filter-feeding shellfish, especially oysters. Because oysters are often consumed raw, this exposes people to large doses of potentially harmful bacteria. Various models are used to predict the abundance of these bacteria in oysters, which guide shellfish harvest policy meant to reduce human health risk. Vibrio abundance and behaviour varies from site to site, suggesting that location-specific studies are needed to establish targeted risk reduction strategies. Moreover, virulence potential, rather than simple abundance, should be also be included in future modeling efforts. © 2016 The Author(s).

  11. Chemical signaling between plants and plant-pathogenic bacteria.

    Science.gov (United States)

    Venturi, Vittorio; Fuqua, Clay

    2013-01-01

    Studies of chemical signaling between plants and bacteria in the past have been largely confined to two models: the rhizobial-legume symbiotic association and pathogenesis between agrobacteria and their host plants. Recent studies are beginning to provide evidence that many plant-associated bacteria undergo chemical signaling with the plant host via low-molecular-weight compounds. Plant-produced compounds interact with bacterial regulatory proteins that then affect gene expression. Similarly, bacterial quorum-sensing signals result in a range of functional responses in plants. This review attempts to highlight current knowledge in chemical signaling that takes place between pathogenic bacteria and plants. This chemical communication between plant and bacteria, also referred to as interkingdom signaling, will likely become a major research field in the future, as it allows the design of specific strategies to create plants that are resistant to plant pathogens.

  12. Interactions between the microbiota and pathogenic bacteria in the gut

    Science.gov (United States)

    Bäumler, Andreas J.; Sperandio, Vanessa

    2016-01-01

    The microbiome has an important role in human health. Changes in the microbiota can confer resistance to or promote infection by pathogenic bacteria. Antibiotics have a profound impact on the microbiota that alters the nutritional landscape of the gut and can lead to the expansion of pathogenic populations. Pathogenic bacteria exploit microbiota-derived sources of carbon and nitrogen as nutrients and regulatory signals to promote their own growth and virulence. By eliciting inflammation, these bacteria alter the intestinal environment and use unique systems for respiration and metal acquisition to drive their expansion. Unravelling the interactions between the microbiota, the host and pathogenic bacteria will produce strategies for manipulating the microbiota against infectious diseases. PMID:27383983

  13. Ecophysiology of the Anammox Bacteria

    NARCIS (Netherlands)

    Kartal, M.B.

    2008-01-01

    Anaerobic ammonium oxidizing (anammox) bacteria oxidize ammonium to dinitrogen gas with nitrite as the electron acceptor. These bacteria are the key players in the global nitrogen cycle, responsible for the most of nitrogen production in natural ecosystems. The anammox process is also a

  14. Money and transmission of bacteria.

    NARCIS (Netherlands)

    Gedik, H.; Voss, T.A.; Voss, A.

    2013-01-01

    Money is one of the most frequently passed items in the world. The aim of this study was to ascertain the survival status of bacteria including Staphylococcus aureus, Escherichia coli, and Vancomycin- Resistant Enterococci (VRE) on banknotes from different countries and the transmission of bacteria

  15. Motility of electric cable bacteria

    DEFF Research Database (Denmark)

    Bjerg, Jesper Tataru; Damgaard, Lars Riis; Holm, Simon Agner

    2016-01-01

    Cable bacteria are filamentous bacteria that electrically couple sulfide oxidation and oxygen reduction at centimeter distances, and observations in sediment environments have suggested that they are motile. By time-lapse microscopy, we found that cable bacteria used gliding motility on surfaces...... with a highly variable speed of 0.50.3 ms1 (meanstandard deviation) and time between reversals of 155108 s. They frequently moved forward in loops, and formation of twisted loops revealed helical rotation of the filaments. Cable bacteria responded to chemical gradients in their environment, and around the oxic......-anoxic interface, they curled and piled up, with straight parts connecting back to the source of sulfide. Thus, it appears that motility serves the cable bacteria in establishing and keeping optimal connections between their distant electron donor and acceptors in a dynamic sediment environment....

  16. Isolation and screening of lactic acid bacteria, Lactococcus lactis ...

    African Journals Online (AJOL)

    In aquaculture probiotic feeding could play a crucial role in developing microbial control strategies, since disease outbreaks are recognized as important constraints to aquaculture production and the fear of antibiotic resistance. In this study, lactic acid bacteria (LAB) strains from the intestinal tissue of African catfish Clarias ...

  17. METHODS FOR DETECTING BACTERIA USING POLYMER MATERIALS

    NARCIS (Netherlands)

    Van Grinsven Bart Robert, Nicolaas; Cleij, Thomas

    2017-01-01

    A method for characterizing bacteria includes passing a liquid containing an analyte comprising a first bacteria and a second bacteria over and in contact with a polymer material on a substrate. The polymer material is formulated to bind to the first bacteria, and the first bacteria binds to the

  18. Tumour targeting with systemically administered bacteria.

    LENUS (Irish Health Repository)

    Morrissey, David

    2012-01-31

    Challenges for oncology practitioners and researchers include specific treatment and detection of tumours. The ideal anti-cancer therapy would selectively eradicate tumour cells, whilst minimising side effects to normal tissue. Bacteria have emerged as biological gene vectors with natural tumour specificity, capable of homing to tumours and replicating locally to high levels when systemically administered. This property enables targeting of both the primary tumour and secondary metastases. In the case of invasive pathogenic species, this targeting strategy can be used to deliver genes intracellularly for tumour cell expression, while non-invasive species transformed with plasmids suitable for bacterial expression of heterologous genes can secrete therapeutic proteins locally within the tumour environment (cell therapy approach). Many bacterial genera have been demonstrated to localise to and replicate to high levels within tumour tissue when intravenously (IV) administered in rodent models and reporter gene tagging of bacteria has permitted real-time visualisation of this phenomenon. Live imaging of tumour colonising bacteria also presents diagnostic potential for this approach. The nature of tumour selective bacterial colonisation appears to be tumour origin- and bacterial species- independent. While originally a correlation was drawn between anaerobic bacterial colonisation and the hypoxic nature of solid tumours, it is recently becoming apparent that other elements of the unique microenvironment within solid tumours, including aberrant neovasculature and local immune suppression, may be responsible. Here, we consider the pre-clinical data supporting the use of bacteria as a tumour-targeting tool, recent advances in the area, and future work required to develop it into a beneficial clinical tool.

  19. Review on SERS of Bacteria

    Directory of Open Access Journals (Sweden)

    Pamela A. Mosier-Boss

    2017-11-01

    Full Text Available Surface enhanced Raman spectroscopy (SERS has been widely used for chemical detection. Moreover, the inherent richness of the spectral data has made SERS attractive for use in detecting biological materials, including bacteria. This review discusses methods that have been used to obtain SERS spectra of bacteria. The kinds of SERS substrates employed to obtain SERS spectra are discussed as well as how bacteria interact with silver and gold nanoparticles. The roll of capping agents on Ag/Au NPs in obtaining SERS spectra is examined as well as the interpretation of the spectral data.

  20. Beer spoilage bacteria and hop resistance

    NARCIS (Netherlands)

    Sakamoto, K; Konings, WN

    2003-01-01

    For brewing industry, beer spoilage bacteria have been problematic for centuries. They include some lactic acid bacteria such as Lactobacillus brevis, Lactobacillus lindneri and Pediococcus damnosus, and some Gram-negative bacteria such as Pectinatus cerevisiiphilus, Pectinatus frisingensis and

  1. Electron transport chains of lactic acid bacteria

    NARCIS (Netherlands)

    Brooijmans, R.J.W.

    2008-01-01

    Lactic acid bacteria are generally considered facultative anaerobic obligate fermentative bacteria. They are unable to synthesize heme. Some lactic acid bacteria are unable to form menaquinone as well. Both these components are cofactors of respiratory (electron transport) chains of prokaryotic

  2. Gut Bacteria Affect Immunotherapy Response

    Science.gov (United States)

    Three new studies have identified intestinal bacteria that appear to influence the response to checkpoint inhibitors. This Cancer Currents blog post explains how the researchers think their findings could be used to improve patients’ responses to these immunotherapy drugs.

  3. hydroxyalkanoate (PHAs) producing bacteria isolated

    African Journals Online (AJOL)

    SERVER

    2007-07-04

    Jul 4, 2007 ... ium (MSM), having inhibitors for Gram positive bacteria and fungi and a mixed ... Two techniques were used for detecting the presence of polymer: staining ... was saline solution at 600 nm wavelength on VARIAN DSM 100.

  4. Thymidine kinase diversity in bacteria

    DEFF Research Database (Denmark)

    Sandrini, Michael; Clausen, A.R.; Munch-Petersen, B.

    2006-01-01

    Thymidine kinases (TKs) appear to be almost ubiquitous and are found in nearly all prokaryotes, eukaryotes, and several viruses. They are the key enzymes in thymidine salvage and activation of several anti-cancer and antiviral drugs. We show that bacterial TKs can be subdivided into 2 groups. The....... The TKs from Gram-positive bacteria are more closely related to the eukaryotic TK1 enzymes than are TKs from Gram-negative bacteria....

  5. Anaerobic bacteria that dechlorinate perchloroethene.

    Science.gov (United States)

    Fathepure, B Z; Nengu, J P; Boyd, S A

    1987-01-01

    In this study, we identified specific cultures of anaerobic bacteria that dechlorinate perchlorethene (PCE). The bacteria that significantly dechlorinated PCE were strain DCB-1, an obligate anaerobe previously shown to dechlorinate chlorobenzoate, and two strains of Methanosarcina. The rate of PCE dechlorination by DCB-1 compared favorably with reported rates of trichloroethene bio-oxidation by methanotrophs. Even higher PCE dechlorination rates were achieved when DCB-1 was grown in a methanogenic consortium. PMID:3426224

  6. [Regulating acid stress resistance of lactic acid bacteria--a review].

    Science.gov (United States)

    Wu, Chongde; Huang, Jun; Zhou, Rongqing

    2014-07-04

    As cell factories, lactic acid bacteria are widely used in food, agriculture, pharmaceutical and other industries. Acid stress is one the important survival challenges encountered by lactic acid bacteria both in fermentation process and in the gastrointestinal tract. Recently, the development of systems biology and metabolic engineering brings unprecedented opportunity for further elucidating the acid tolerance mechanisms and improving the acid stress resistance of lactic acid bacteria. This review addresses physiological mechanisms of lactic acid bacteria during acid stress. Moreover, strategies to improve the acid stress resistance of lactic acid were proposed.

  7. Why do bacteria divide?

    Science.gov (United States)

    Norris, Vic

    2015-01-01

    The problem of not only how but also why cells divide can be tackled using recent ideas. One idea from the origins of life – Life as independent of its constituents – is that a living entity like a cell is a particular pattern of connectivity between its constituents. This means that if the growing cell were just to get bigger the average connectivity between its constituents per unit mass – its cellular connectivity – would decrease and the cell would lose its identity. The solution is division which restores connectivity. The corollary is that the cell senses decreasing cellular connectivity and uses this information to trigger division. A second idea from phenotypic diversity – Life on the Scales of Equilibria – is that a bacterium must find strategies that allow it to both survive and grow. This means that it has learnt to reconcile the opposing constraints that these strategies impose. The solution is that the cell cycle generates daughter cells with different phenotypes based on sufficiently complex equilibrium (E) and non-equilibrium (NE) cellular compounds and structures appropriate for survival and growth, respectively, alias ‘hyperstructures.’ The corollary is that the cell senses both the quantity of E material and the intensity of use of NE material and then uses this information to trigger the cell cycle. A third idea from artificial intelligence – Competitive Coherence – is that a cell selects the active subset of elements that actively determine its phenotype from a much larger set of available elements. This means that the selection of an active subset of a specific size and composition must be done so as to generate both a coherent cell state, in which the cell’s contents work together harmoniously, and a coherent sequence of cell states, each coherent with respect to itself and to an unpredictable environment. The solution is the use of a range of mechanisms ranging from hyperstructure dynamics to the cell cycle itself. PMID

  8. Antimicrobial Activity – The Most Important Property of Probiotic and Starter Lactic Acid Bacteria

    Directory of Open Access Journals (Sweden)

    Blaženka Kos

    2010-01-01

    Full Text Available The antimicrobial activity of industrially important lactic acid bacteria as starter cultures and probiotic bacteria is the main subject of this review. This activity has been attributed to the production of metabolites such as organic acids (lactic and acetic acid, hydrogen peroxide, ethanol, diacetyl, acetaldehyde, acetoine, carbon dioxide, reuterin, reutericyclin and bacteriocins. The potential of using bacteriocins of lactic acid bacteria, primarily used as biopreservatives, represents a perspective, alternative antimicrobial strategy for continuously increasing problem with antibiotic resistance. Another strategy in resolving this problem is an application of probiotics for different gastrointestinal and urogenital infection therapies.

  9. Human body may produce bacteria.

    Science.gov (United States)

    Salerian, Alen J

    2017-06-01

    "Human body may produce bacteria" proposes that human body may produce bacteria and represent an independent source of infections contrary to the current paradigm of infectious disorders proposed by Louis Pasteur in 1880. The following observations are consistent with this hypothesis: A. Bidirectional transformations of both living and nonliving things have been commonly observed in nature. B. Complex multicellular organisms harbor the necessary properties to produce bacteria (water, nitrogen and oxygen). C. Physical laws suggest any previously observed phenomenon or action will occur again (life began on earth; a non living thing). D. Animal muscle cells may generate energy (fermentation). E. Sterilized food products (i.e. boiled eggs), may produce bacteria and fungus under special conditions and without any exposure to foreign living cells. "Human body may produce bacteria" may challenge the current medical paradigm that views human infectious disorders as the exclusive causative byproducts of invading foreign cells. It may also introduce new avenues to treat infectious disorders. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Horizontal gene transfer between bacteria.

    Science.gov (United States)

    Heuer, Holger; Smalla, Kornelia

    2007-01-01

    Horizontal gene transfer (HGT) refers to the acquisition of foreign genes by organisms. The occurrence of HGT among bacteria in the environment is assumed to have implications in the risk assessment of genetically modified bacteria which are released into the environment. First, introduced genetic sequences from a genetically modified bacterium could be transferred to indigenous micro-organisms and alter their genome and subsequently their ecological niche. Second, the genetically modified bacterium released into the environment might capture mobile genetic elements (MGE) from indigenous micro-organisms which could extend its ecological potential. Thus, for a risk assessment it is important to understand the extent of HGT and genome plasticity of bacteria in the environment. This review summarizes the present state of knowledge on HGT between bacteria as a crucial mechanism contributing to bacterial adaptability and diversity. In view of the use of GM crops and microbes in agricultural settings, in this mini-review we focus particularly on the presence and role of MGE in soil and plant-associated bacteria and the factors affecting gene transfer.

  11. Chitin Degradation In Marine Bacteria

    DEFF Research Database (Denmark)

    Paulsen, Sara; Machado, Henrique; Gram, Lone

    2015-01-01

    Introduction: Chitin is the most abundant polymer in the marine environment and the second most abundant in nature. Chitin does not accumulate on the ocean floor, because of microbial breakdown. Chitin degrading bacteria could have potential in the utilization of chitin as a renewable carbon...... and nitrogen source in the fermentation industry.Methods: Here, whole genome sequenced marine bacteria were screened for chitin degradation using phenotypic and in silico analyses.Results: The in silico analyses revealed the presence of three to nine chitinases in each strain, however the number of chitinases...... chitin regulatory system.Conclusions: This study has provided insight into the ecology of chitin degradation in marine bacteria. It also served as a basis for choosing a more efficient chitin degrading production strain e.g. for the use of chitin waste for large-scale fermentations....

  12. Methylotrophic bacteria in sustainable agriculture.

    Science.gov (United States)

    Kumar, Manish; Tomar, Rajesh Singh; Lade, Harshad; Paul, Diby

    2016-07-01

    Excessive use of chemical fertilizers to increase production from available land has resulted in deterioration of soil quality. To prevent further soil deterioration, the use of methylotrophic bacteria that have the ability to colonize different habitats, including soil, sediment, water, and both epiphytes and endophytes as host plants, has been suggested for sustainable agriculture. Methylotrophic bacteria are known to play a significant role in the biogeochemical cycle in soil ecosystems, ultimately fortifying plants and sustaining agriculture. Methylotrophs also improve air quality by using volatile organic compounds such as dichloromethane, formaldehyde, methanol, and formic acid. Additionally, methylotrophs are involved in phosphorous, nitrogen, and carbon cycling and can help reduce global warming. In this review, different aspects of the interaction between methylotrophs and host plants are discussed, including the role of methylotrophs in phosphorus acquisition, nitrogen fixation, phytohormone production, iron chelation, and plant growth promotion, and co-inoculation of these bacteria as biofertilizers for viable agriculture practices.

  13. Acetic Acid Bacteria as Symbionts of Insects

    KAUST Repository

    Crotti, Elena; Chouaia, Bessem; Alma, Alberto; Favia, Guido; Bandi, Claudio; Bourtzis, Kostas; Daffonchio, Daniele

    2016-01-01

    Acetic acid bacteria (AAB) are being increasingly described as associating with different insect species that rely on sugar-based diets. AAB have been found in several insect orders, among them Diptera, Hemiptera, and Hymenoptera, including several vectors of plant, animal, and human diseases. AAB have been shown to associate with the epithelia of different organs of the host, they are able to move within the insect’s body and to be transmitted horizontally and vertically. Here, we review the ecology of AAB and examine their relationships with different insect models including mosquitoes, leafhoppers, and honey bees. We also discuss the potential use of AAB in symbiont-based control strategies, such as “Trojan-horse” agents, to block the transmission of vector-borne diseases.

  14. Acetic Acid Bacteria as Symbionts of Insects

    KAUST Repository

    Crotti, Elena

    2016-06-14

    Acetic acid bacteria (AAB) are being increasingly described as associating with different insect species that rely on sugar-based diets. AAB have been found in several insect orders, among them Diptera, Hemiptera, and Hymenoptera, including several vectors of plant, animal, and human diseases. AAB have been shown to associate with the epithelia of different organs of the host, they are able to move within the insect’s body and to be transmitted horizontally and vertically. Here, we review the ecology of AAB and examine their relationships with different insect models including mosquitoes, leafhoppers, and honey bees. We also discuss the potential use of AAB in symbiont-based control strategies, such as “Trojan-horse” agents, to block the transmission of vector-borne diseases.

  15. Bacteria of Phlebotominae Sand Flies Collected in Western Iran

    Directory of Open Access Journals (Sweden)

    Somayeh Rafatbakhsh-Iran

    2015-08-01

    Full Text Available Microorganisms particularly bacteria presenting in insects such as Phlebotominae may play an important role in the epidemiology of human infectious disease. Nowadays, because of vector implications, the routine methods of controlling and spraying have no more beneficial effects on vectors and reservoirs. Little knows about the prevalence and diversity of sand fly bacteria. The main objective of this study was to determine the presence of bacteria of phlebotominae sand flies collected in Hamadan, west of Iran. This information is important in order to development of vector control strategies. The microbial flora of Phlebotomus papatasi and P. sergenti the main vector of Cutaneous Leishmaniasis in the old world, were investigated. We characterized 8 bacteria, including 5 Gram-negative bacteria: Acinetobacter lwoffii, Pseudomonas aeruginosa, Enterobacter cloacae, Edvardsiela sp. and Proteus mirabilis and Gram-positive bacteria: Bacillus subtilis, Staphylococcus saprophyticus and Micrococcus luteus. Our study provides some data on the microbiota diversity of field-collected sand flies for the first time in Hamadan. Our results indicate that there is a range of variation of aerobic bacteria inhabiting sand fly, which possibly reflect the ecological condition of the habitat where the fly breeds. Microbiota is increasingly regarded as an important factor for modulating vector competence in insect vectors. So, mirobiota can be effects on the biology of phlebotominae and their roles in the sandfly-Leishmania interaction. Further experiments are required to clearly delineate the vectorial role of sand flies. Because it is probable that in the future, factors such as environmental changes, migration and urbanization can ease the transmission of leishmaniasis in this area.

  16. Bacteria versus selenium: A view from the inside out

    Science.gov (United States)

    Staicu, Lucian; Oremland, Ronald S.; Tobe, Ryuta; Mihara, Hisaaki

    2017-01-01

    Bacteria and selenium (Se) are closely interlinked as the element serves both essential nutrient requirements and energy generation functions. However, Se can also behave as a powerful toxicant for bacterial homeostasis. Conversely, bacteria play a tremendous role in the cycling of Se between different environmental compartments, and bacterial metabolism has been shown to participate to all valence state transformations undergone by Se in nature. Bacteria possess an extensive molecular repertoire for Se metabolism. At the end of the 1980s, a novel mode of anaerobic respiration based on Se oxyanions was experimentally documented for the first time. Following this discovery, specific enzymes capable of reducing Se oxyanions and harvesting energy were found in a number of anaerobic bacteria. The genes involved in the expression of these enzymes have later been identified and cloned. This iterative approach undertaken outside-in led to the understanding of the molecular mechanisms of Se transformations in bacteria. Based on the extensive knowledge accumulated over the years, we now have a full(er) view from the inside out, from DNA-encoding genes to enzymes and thermodynamics. Bacterial transformations of Se for assimilatory purposes have been the object of numerous studies predating the investigation of Se respiration. Remarkable contributions related to the understating of the molecular picture underlying seleno-amino acid biosynthesis are reviewed herein. Under certain circumstances, Se is a toxicant for bacterial metabolism and bacteria have evolved strategies to counteract this toxicity, most notably by the formation of elemental Se (nano)particles. Several biotechnological applications, such as the production of functional materials and the biofortification of crop species using Se-utilizing bacteria, are presented in this chapter.

  17. Antibiotic effects against periodontal bacteria in organ cultured tissue.

    Science.gov (United States)

    Takeshita, Masaaki; Haraguchi, Akira; Miura, Mayumi; Hamachi, Takafumi; Fukuda, Takao; Sanui, Terukazu; Takano, Aiko; Nishimura, Fusanori

    2017-02-01

    Mechanical reduction of infectious bacteria by using physical instruments is considered the principal therapeutic strategy for periodontal disease; addition of antibiotics is adjunctive. However, local antibiotic treatment, combined with conventional mechanical debridement, has recently been shown to be more effective in periodontitis subjects with type 2 diabetes. This suggests that some bacteria may invade the inflamed inner gingival epithelium, and mechanical debridement alone will be unable to reduce these bacteria completely. Therefore, we tried to establish infected organ culture models that mimic the inner gingival epithelium and aimed to see the effects of antibiotics in these established models. Mouse dorsal skin epithelia were isolated, and periodontal bacteria were injected into the epithelia. Infected epithelia were incubated with test antibiotics, and colony-forming ability was evaluated. Results indicated that effective antibiotics differed according to injected bacteria and the bacterial combinations tested. Overall, in organ culture model, the combination of amoxicillin or cefdinir and metronidazole compensate for the effects of less effective bacterial combinations on each other. This in vitro study would suggest effective periodontal treatment regimens, especially for severe periodontitis.

  18. MAGNETIC BACTERIA AND THEIR POTENTIAL APPLICATIONS: A REVIEW ARTICLE

    Directory of Open Access Journals (Sweden)

    Sara Rajab Eljmeli

    2017-03-01

    Full Text Available Introduction: This outline explores the scientific discovery concerning the magnetotactic bacteria (MTB. The results of the discovery are used in microbiology, mineralogy, limnology, physics, biophysics, chemistry, biochemistry, geology, crystallography, and astrobiology. Magnetosomes of the MTB are organized in linear chains and orient the cell body along geomagnetic field lines while flagella actively propel the cells, resulting in so-called magnetotaxis. Materials and Methods: The review article about the magnetotactic bacteria is a collection of many research papers from different institutes. The emerging important points about this review lie in: (1 any biological system is capable of producing magnetic biomaterials such as magnetite (Fe3O4 and gregite (Fe3S4; (2 the navigation of these nano-crystals in the biological system is interconnected with the Earth’s magnetic field. Results: The researchers involved in the study have shown that the magnetotactic bacteria do respond to a magnetic field. This makes them attractive for biomedical and industrial applications because of the availability of superior electromagnets, superconducting magnets and permanent magnet. Magnetic bacteria can also be used as a diagnostic tool in the detection of imperfections even at the nanoscale. Discussion and Conclusions: Although the importance of this issue is still limitedly used in medical area, more performance is necessary to explore the world of these bacteria that are candidate for new industry and new therapy strategies in biotechnology and medical fields.

  19. Novel Adaptive Bacteria Foraging Algorithms for Global Optimization

    Directory of Open Access Journals (Sweden)

    Ahmad N. K. Nasir

    2014-01-01

    Full Text Available This paper presents improved versions of bacterial foraging algorithm (BFA. The chemotaxis feature of bacteria through random motion is an effective strategy for exploring the optimum point in a search area. The selection of small step size value in the bacteria motion leads to high accuracy in the solution but it offers slow convergence. On the contrary, defining a large step size in the motion provides faster convergence but the bacteria will be unable to locate the optimum point hence reducing the fitness accuracy. In order to overcome such problems, novel linear and nonlinear mathematical relationships based on the index of iteration, index of bacteria, and fitness cost are adopted which can dynamically vary the step size of bacteria movement. The proposed algorithms are tested with several unimodal and multimodal benchmark functions in comparison with the original BFA. Moreover, the application of the proposed algorithms in modelling of a twin rotor system is presented. The results show that the proposed algorithms outperform the predecessor algorithm in all test functions and acquire better model for the twin rotor system.

  20. ENDOSPORES OF THERMOPHILIC FERMENTATIVE BACTERIA

    DEFF Research Database (Denmark)

    Volpi, Marta

    2016-01-01

    solely based on endospores of sulphate-reducing bacteria (SRB), which presumably constitute only a small fraction of the total thermophilic endospore community reaching cold environments. My PhD project developed an experimental framework for using thermophilic fermentative endospores (TFEs) to trace...

  1. Alternative sources of Legionella bacteria

    NARCIS (Netherlands)

    van Heijnsbergen, H.H.L.

    2017-01-01

    Legionella bacteria can cause Legionnaires’ disease (LD) in humans. Symptoms of LD can range from mild disease to severe pneumonia with sometimes fatal outcome. In the Netherlands, the most important infective agent is Legionella pneumophila. L. pneumophila infection is associated with aquatic

  2. Programmed survival of soil bacteria

    DEFF Research Database (Denmark)

    Jensen, Lars Bogø; Molin, Søren; Sternberg, Claus

    Biological containment systems have been developed for Pseudomonas putida and related soil bacteria. The systems are based on combinations of lethal genes and regulated gene expression. Two types of killing function have been employed: 1) A membrane protein interfering with the membrane potential...

  3. Automated radiometric detection of bacteria

    International Nuclear Information System (INIS)

    Waters, J.R.

    1974-01-01

    A new radiometric method called BACTEC, used for the detection of bacteria in cultures or in supposedly sterile samples, was discussed from the standpoint of methodology, both automated and semi-automated. Some of the results obtained so far were reported and some future applications and development possibilities were described. In this new method, the test sample is incubated in a sealed vial with a liquid culture medium containing a 14 C-labeled substrate. If bacteria are present, they break down the substrate, producing 14 CO 2 which is periodically extracted from the vial as a gas and is tested for radioactivity. If this gaseous radioactivity exceeds a threshold level, it is evidence of bacterial presence and growth in the test vial. The first application was for the detection of bacteria in the blood cultures of hospital patients. Data were presented showing typical results. Also discussed were future applications, such as rapid screening for bacteria in urine industrial sterility testing and the disposal of used 14 C substrates. (Mukohata, S.)

  4. Synthetic Biology in Streptomyces Bacteria

    NARCIS (Netherlands)

    Medema, Marnix H.; Breitling, Rainer; Takano, Eriko

    2011-01-01

    Actinomycete bacteria of the genus Streptomyces are major producers of bioactive compounds for the biotechnology industry. They are the source of most clinically used antibiotics, as well as of several widely used drugs against common diseases, including cancer . Genome sequencing has revealed that

  5. Deodorant bacteria; Des bacteries desodorisantes

    Energy Technology Data Exchange (ETDEWEB)

    Fanlo, J.L. [Ecole Nationale Superieure des Mines, 30 - Ales (France)

    1998-02-01

    Purifying bacteria: if this concept is not new, its application to gases cleansing has only been developed recently. This method allows to eliminate the volatile organic compounds and the gaseous effluents odors which come from industrial sites. Three bioreactors types exist at the present time. Their principles are explained. (O.M.) 6 refs.

  6. Fuzzy species among recombinogenic bacteria

    Directory of Open Access Journals (Sweden)

    Fraser Christophe

    2005-03-01

    Full Text Available Abstract Background It is a matter of ongoing debate whether a universal species concept is possible for bacteria. Indeed, it is not clear whether closely related isolates of bacteria typically form discrete genotypic clusters that can be assigned as species. The most challenging test of whether species can be clearly delineated is provided by analysis of large populations of closely-related, highly recombinogenic, bacteria that colonise the same body site. We have used concatenated sequences of seven house-keeping loci from 770 strains of 11 named Neisseria species, and phylogenetic trees, to investigate whether genotypic clusters can be resolved among these recombinogenic bacteria and, if so, the extent to which they correspond to named species. Results Alleles at individual loci were widely distributed among the named species but this distorting effect of recombination was largely buffered by using concatenated sequences, which resolved clusters corresponding to the three species most numerous in the sample, N. meningitidis, N. lactamica and N. gonorrhoeae. A few isolates arose from the branch that separated N. meningitidis from N. lactamica leading us to describe these species as 'fuzzy'. Conclusion A multilocus approach using large samples of closely related isolates delineates species even in the highly recombinogenic human Neisseria where individual loci are inadequate for the task. This approach should be applied by taxonomists to large samples of other groups of closely-related bacteria, and especially to those where species delineation has historically been difficult, to determine whether genotypic clusters can be delineated, and to guide the definition of species.

  7. Alcoholic pancreatitis: A tale of spirits and bacteria

    OpenAIRE

    Vonlaufen, Alain; Spahr, Laurent; Apte, Minoti V; Frossard, Jean-Louis

    2014-01-01

    Alcohol is a major cause of chronic pancreatitis. About 5% of alcoholics will ever suffer from pancreatitis, suggesting that additional co-factors are required to trigger an overt disease. Experimental work has implicated lipopolysaccharide, from gut-derived bacteria, as a potential co-factor of alcoholic pancreatitis. This review discusses the effects of alcohol on the gut flora, the gut barrier, the liver-and the pancreas and proposes potential interventional strategies. A better understand...

  8. Plant Growth-Promoting Bacteria: Mechanisms and Applications

    Directory of Open Access Journals (Sweden)

    Bernard R. Glick

    2012-01-01

    Full Text Available The worldwide increases in both environmental damage and human population pressure have the unfortunate consequence that global food production may soon become insufficient to feed all of the world's people. It is therefore essential that agricultural productivity be significantly increased within the next few decades. To this end, agricultural practice is moving toward a more sustainable and environmentally friendly approach. This includes both the increasing use of transgenic plants and plant growth-promoting bacteria as a part of mainstream agricultural practice. Here, a number of the mechanisms utilized by plant growth-promoting bacteria are discussed and considered. It is envisioned that in the not too distant future, plant growth-promoting bacteria (PGPB will begin to replace the use of chemicals in agriculture, horticulture, silviculture, and environmental cleanup strategies. While there may not be one simple strategy that can effectively promote the growth of all plants under all conditions, some of the strategies that are discussed already show great promise.

  9. Quantitative relationship between antibiotic exposure and the acquisition and transmission of resistance in bacteria in the laboratory

    NARCIS (Netherlands)

    Händel, N.

    2015-01-01

    The worldwide emergence and spread of antibiotic resistant bacteria represent a major threat to human health care as the chance of therapy failure and costs for treatment increase. To curb the continuous rise of drug resistant bacteria worldwide, new strategies are urgently needed that counteract

  10. Antimicrobial Photodynamic Therapy to Kill Gram-negative Bacteria

    Science.gov (United States)

    Sperandio, Felipe F; Huang, Ying-Ying; Hamblin, Michael R

    2013-01-01

    Antimicrobial photodynamic therapy (PDT) or photodynamic inactivation (PDI) is a new promising strategy to eradicate pathogenic microorganisms such as Gram-positive and Gram-negative bacteria, yeasts and fungi. The search for new approaches that can kill bacteria but do not induce the appearance of undesired drug-resistant strains suggests that PDT may have advantages over traditional antibiotic therapy. PDT is a non-thermal photochemical reaction that involves the simultaneous presence of visible light, oxygen and a dye or photosensitizer (PS). Several PS have been studied for their ability to bind to bacteria and efficiently generate reactive oxygen species (ROS) upon photostimulation. ROS are formed through type I or II mechanisms and may inactivate several classes of microbial cells including Gram-negative bacteria such as Pseudomonas aeruginosa, which are typically characterized by an impermeable outer cell membrane that contains endotoxins and blocks antibiotics, dyes, and detergents, protecting the sensitive inner membrane and cell wall. This review covers significant peer-reviewed articles together with US and World patents that were filed within the past few years and that relate to the eradication of Gram-negative bacteria via PDI or PDT. It is organized mainly according to the nature of the PS involved and includes natural or synthetic food dyes; cationic dyes such as methylene blue and toluidine blue; tetrapyrrole derivatives such as phthalocyanines, chlorins, porphyrins, chlorophyll and bacteriochlorophyll derivatives; functionalized fullerenes; nanoparticles combined with different PS; other formulations designed to target PS to bacteria; photoactive materials and surfaces; conjugates between PS and polycationic polymers or antibodies; and permeabilizing agents such as EDTA, PMNP and CaCl2. The present review also covers the different laboratory animal models normally used to treat Gram-negative bacterial infections with antimicrobial PDT. PMID

  11. Genetics of Lactic Acid Bacteria

    Science.gov (United States)

    Zagorec, Monique; Anba-Mondoloni, Jamila; Coq, Anne-Marie Crutz-Le; Champomier-Vergès, Marie-Christine

    Many meat (or fish) products, obtained by the fermentation of meat originating from various animals by the flora that naturally contaminates it, are part of the human diet since millenaries. Historically, the use of bacteria as starters for the fermentation of meat, to produce dry sausages, was thus performed empirically through the endogenous micro-biota, then, by a volunteer addition of starters, often performed by back-slopping, without knowing precisely the microbial species involved. It is only since about 50 years that well defined bacterial cultures have been used as starters for the fermentation of dry sausages. Nowadays, the indigenous micro-biota of fermented meat products is well identified, and the literature is rich of reports on the identification of lactic acid bacteria (LAB) present in many traditional fermented products from various geographical origin, obtained without the addition of commercial starters (See Talon, Leroy, & Lebert, 2007, and references therein).

  12. Re-engineering bacteria for ethanol production

    Science.gov (United States)

    Yomano, Lorraine P; York, Sean W; Zhou, Shengde; Shanmugam, Keelnatham; Ingram, Lonnie O

    2014-05-06

    The invention provides recombinant bacteria, which comprise a full complement of heterologous ethanol production genes. Expression of the full complement of heterologous ethanol production genes causes the recombinant bacteria to produce ethanol as the primary fermentation product when grown in mineral salts medium, without the addition of complex nutrients. Methods for producing the recombinant bacteria and methods for producing ethanol using the recombinant bacteria are also disclosed.

  13. Oligotrophic bacteria isolated from clinical materials.

    OpenAIRE

    Tada, Y; Ihmori, M; Yamaguchi, J

    1995-01-01

    Oligotrophic bacteria (oligotrophs) are microorganisms that grow in extremely nutritionally deficient conditions in which the concentrations of organic substances are low. Many oligotrophic bacteria were isolated from clinical materials including urine, sputum, swabbings of the throat, vaginal discharges, and others. Seventy-seven strains of oligotrophic bacteria from 871 samples of clinical material were isolated. A relatively higher frequency of isolation of oligotrophic bacteria was shown ...

  14. Geobiology of Marine Magnetotactic Bacteria

    Science.gov (United States)

    2006-06-01

    prokaryotic cells of diverse phylogeny when grown in media containing 45 1mM iron, suggesting some kind of detoxification function . The inclusions were...salt marsh productivity. FISH also showed that aggregates consist of genetically identical cells. QPCR data indicated that populations are finely...my advisor Katrina Edwards for taking a chance on someone who initially knew nothing about magnetotactic bacteria, microbial ecology , or microbiology

  15. Nitrogen-fixing methane-utilizing bacteria

    NARCIS (Netherlands)

    Bont, de J.A.M.

    1976-01-01

    Methane occurs abundantly in nature. In the presence of oxygen this gas may be metabolized by bacteria that are able to use it as carbon and energy source. Several types of bacteria involved in the oxidation of methane have been described in literature. Methane-utilizing bacteria have in

  16. Laser-Based Identification of Pathogenic Bacteria

    Science.gov (United States)

    Rehse, Steven J.

    2009-01-01

    Bacteria are ubiquitous in our world. From our homes, to our work environment, to our own bodies, bacteria are the omnipresent although often unobserved companions to human life. Physicists are typically untroubled professionally by the presence of these bacteria, as their study usually falls safely outside the realm of our typical domain. In the…

  17. Ecology of mycophagous collimonas bacteria in soil

    NARCIS (Netherlands)

    Höppener-Ogawa, Sachie

    2008-01-01

    Bacteria belonging to the genus Collimonas consist of soil bacteria that can grow at expense of living fungal hyphae i.e. they are mycophagous. This PhD studies deals with the ecology of mycophagous bacteria in soil using collimonads as model organisms. Collimonads were found to be widely

  18. Stress Physiology of Lactic Acid Bacteria

    Science.gov (United States)

    Papadimitriou, Konstantinos; Alegría, Ángel; Bron, Peter A.; de Angelis, Maria; Gobbetti, Marco; Kleerebezem, Michiel; Lemos, José A.; Linares, Daniel M.; Ross, Paul; Stanton, Catherine; Turroni, Francesca; van Sinderen, Douwe; Varmanen, Pekka; Ventura, Marco; Zúñiga, Manuel; Tsakalidou, Effie

    2016-01-01

    SUMMARY Lactic acid bacteria (LAB) are important starter, commensal, or pathogenic microorganisms. The stress physiology of LAB has been studied in depth for over 2 decades, fueled mostly by the technological implications of LAB robustness in the food industry. Survival of probiotic LAB in the host and the potential relatedness of LAB virulence to their stress resilience have intensified interest in the field. Thus, a wealth of information concerning stress responses exists today for strains as diverse as starter (e.g., Lactococcus lactis), probiotic (e.g., several Lactobacillus spp.), and pathogenic (e.g., Enterococcus and Streptococcus spp.) LAB. Here we present the state of the art for LAB stress behavior. We describe the multitude of stresses that LAB are confronted with, and we present the experimental context used to study the stress responses of LAB, focusing on adaptation, habituation, and cross-protection as well as on self-induced multistress resistance in stationary phase, biofilms, and dormancy. We also consider stress responses at the population and single-cell levels. Subsequently, we concentrate on the stress defense mechanisms that have been reported to date, grouping them according to their direct participation in preserving cell energy, defending macromolecules, and protecting the cell envelope. Stress-induced responses of probiotic LAB and commensal/pathogenic LAB are highlighted separately due to the complexity of the peculiar multistress conditions to which these bacteria are subjected in their hosts. Induction of prophages under environmental stresses is then discussed. Finally, we present systems-based strategies to characterize the “stressome” of LAB and to engineer new food-related and probiotic LAB with improved stress tolerance. PMID:27466284

  19. AIDS: "it's the bacteria, stupid!".

    Science.gov (United States)

    Broxmeyer, Lawrence; Cantwell, Alan

    2008-11-01

    Acid-fast tuberculous mycobacterial infections are common in AIDS and are regarded as secondary "opportunistic infections." According to the National Institute of Allergy and Infectious Diseases, TB is the major attributable cause of death in AIDS patients. Could such bacteria play a primary or causative role in AIDS? Certainly, In screening tests for HIV, there is frequent, up to 70%, cross-reactivity, between the gag and pol proteins of HIV and patients with mycobacterial infections such as tuberculosis. By 1972, five years before gays started dying in the U.S., Rolland wrote Genital Tuberculosis, a Forgotten Disease? And ironically, in 1979, on the eve of AIDS recognition, Gondzik and Jasiewicz showed that even in the laboratory, genitally infected tubercular male guinea pigs could infect healthy females through their semen by an HIV-compatible ratio of 1 in 6 or 17%, prompting him to warn his patients that not only was tuberculosis a sexually transmitted disease, but also the necessity of the application of suitable contraceptives, such as condoms, to avoid it. Gondzik's solution and date of publication are chilling; his findings significant. Since 1982 Cantwell et al found acid-fast bacteria closely related to tuberculosis (TB) and atypical tuberculosis in AIDS tissue. On the other hand molecular biologist and virologist Duesberg, who originally defined retroviral ultrastructure, has made it clear that HIV is not the cause of AIDS and that the so-called AIDS retrovirus has never been isolated in its pure state. Dr. Etienne de Harven, first to examine retroviruses under the electron, agrees. In 1993 HIV co-discoverer Luc Montagnier reported on cell-wall-deficient (CWD) bacteria which he called "mycoplasma" in AIDS tissue. He suspected these as a necessary "co-factor" for AIDS. Remarkably, Montagnier remained silent on Cantwell's reports of acid-fast bacteria which could simulate "mycoplasma" in AIDS tissue. Mattman makes clear that the differentiation between

  20. Subversion of the cytoskeleton by intracellular bacteria: lessons from Listeria, Salmonella, and Vibrio

    Science.gov (United States)

    de Souza Santos, Marcela; Orth, Kim

    2018-01-01

    Summary Entry into host cells and intracellular persistence by invasive bacteria are tightly coupled to the ability of the bacterium to disrupt the eukaryotic cytoskeletal machinery. Herein we review the main strategies used by three intracellular pathogens to harness key modulators of the cytoskeleton. Two of these bacteria, namely Listeria monocytogenes and Salmonella enterica serovar Typhimurium, exhibit quite distinct intracellular lifestyles, and therefore, provide a comprehensive panel for the understanding of the intricate bacteria-cytoskeleton interplay during infections. The emerging intracellular pathogen Vibrio parahaemolyticus is depicted as a developing model for the uncovering of novel mechanisms used to hijack the cytoskeleton. PMID:25440316

  1. Isolation of previously uncultured rumen bacteria by dilution to extinction using a new liquid culture medium.

    Science.gov (United States)

    Kenters, Nikki; Henderson, Gemma; Jeyanathan, Jeyamalar; Kittelmann, Sandra; Janssen, Peter H

    2011-01-01

    A new anaerobic medium that mimics the salts composition of rumen fluid was used in conjunction with a dilution method of liquid culture to isolate fermentative bacteria from the rumen of a grass-fed sheep. The aim was to inoculate a large number of culture tubes each with a mean of 97% sequence identity to genes of uncultured bacteria detected in various gastrointestinal environments. This strategy has therefore allowed us to cultivate many novel rumen bacteria, opening the way to overcoming the lack of cultures of many of the groups detected using cultivation-independent methods. Copyright © 2010 Elsevier B.V. All rights reserved.

  2. The seaweed holobiont: understanding seaweed-bacteria interactions.

    Science.gov (United States)

    Egan, Suhelen; Harder, Tilmann; Burke, Catherine; Steinberg, Peter; Kjelleberg, Staffan; Thomas, Torsten

    2013-05-01

    Seaweeds (macroalgae) form a diverse and ubiquitous group of photosynthetic organisms that play an essential role in aquatic ecosystems. These ecosystem engineers contribute significantly to global primary production and are the major habitat formers on rocky shores in temperate waters, providing food and shelter for aquatic life. Like other eukaryotic organisms, macroalgae harbor a rich diversity of associated microorganisms with functions related to host health and defense. In particular, epiphytic bacterial communities have been reported as essential for normal morphological development of the algal host, and bacteria with antifouling properties are thought to protect chemically undefended macroalgae from detrimental, secondary colonization by other microscopic and macroscopic epibiota. This tight relationship suggests that macroalgae and epiphytic bacteria interact as a unified functional entity or holobiont, analogous to the previously suggested relationship in corals. Moreover, given that the impact of diseases in marine ecosystems is apparently increasing, understanding the role of bacteria as saprophytes and pathogens in seaweed communities may have important implications for marine management strategies. This review reports on the recent advances in the understanding of macroalgal-bacterial interactions with reference to the diversity and functional role of epiphytic bacteria in maintaining algal health, highlighting the holobiont concept. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  3. Control of Fusarium Wilt of Chili With Chitinolytic Bacteria

    Directory of Open Access Journals (Sweden)

    DWI SURYANTO

    2010-03-01

    Full Text Available Biological control of plant disease using antagonistic microorganism has been obtaining much attention and implemented for decades. One of the potential microorganisms used in this strategy is chitinolytic bacteria. Utilization of this bacteria ranges from cell life, enzymes, genes, or other metabolites. In this study, we examined the ability of chitinolytic bacteria as a biocontrol agent of Fusarium wilt of red chili (Capsicum annuum L. seedlings. The ability of chitinolytic bacteria to suppress the disease was evaluated by soaking red chili seeds in the bacterial isolates solution for 30 minutes prior seedling. Percentage of seedling of treated chili seed at end of study (4-weeks ranging from 46 to 82.14%. Relative reduction of the seedling damping-off was observed in all bacterial treatment ranged from 28.57 to 60.71%. Furthermore, manifestation of bacterial suppression to Fusarium wilt was also exhibited by increasing of seedling height (ranged from 7.33 to 7.87 cm compared to 6.88 cm and dry-weight (ranged from 2.7 to 4.3 mg compared to 2.3 mg. However, no significant effect was observed in leaf number. Then, from all chitinolytic isolates tested, BK08 was the most potential candidate for biological control agent of Fusarium wilt in chili seedling.

  4. The role of anaerobic bacteria in the cystic fibrosis airway.

    Science.gov (United States)

    Sherrard, Laura J; Bell, Scott C; Tunney, Michael M

    2016-11-01

    Anaerobic bacteria are not only normal commensals, but are also considered opportunistic pathogens and have been identified as persistent members of the lower airway community in people with cystic fibrosis of all ages and stages of disease. Currently, the role of anaerobic bacteria in cystic fibrosis lower airway disease is not well understood. Therefore, this review describes the recent studies relating to the potential pathophysiological role(s) of anaerobes within the cystic fibrosis lungs. The most frequently identified anaerobic bacteria in the lower airways are common to both cystic fibrosis and healthy lungs. Studies have shown that in cystic fibrosis, the relative abundance of anaerobes fluctuates in the lower airways with reduced lung function and increased inflammation associated with a decreased anaerobic load. However, anaerobes found within the lower airways also produce virulence factors, may cause a host inflammatory response and interact synergistically with recognized pathogens. Anaerobic bacteria are potentially members of the airway microbiota in health but could also contribute to the pathogenesis of lower airway disease in cystic fibrosis via both direct and indirect mechanisms. A personalized treatment strategy that maintains a normal microbial community may be possible in the future.

  5. 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...

  6. Controlling weeds with fungi, bacteria and viruses: a review

    Science.gov (United States)

    Harding, Dylan P.; Raizada, Manish N.

    2015-01-01

    Weeds are a nuisance in a variety of land uses. The increasing prevalence of both herbicide resistant weeds and bans on cosmetic pesticide use has created a strong impetus to develop novel strategies for controlling weeds. The application of bacteria, fungi and viruses to achieving this goal has received increasingly great attention over the last three decades. Proposed benefits to this strategy include reduced environmental impact, increased target specificity, reduced development costs compared to conventional herbicides and the identification of novel herbicidal mechanisms. This review focuses on examples from North America. Among fungi, the prominent genera to receive attention as bioherbicide candidates include Colletotrichum, Phoma, and Sclerotinia. Among bacteria, Xanthomonas and Pseudomonas share this distinction. The available reports on the application of viruses to controlling weeds are also reviewed. Focus is given to the phytotoxic mechanisms associated with bioherbicide candidates. Achieving consistent suppression of weeds in field conditions is a common challenge to this control strategy, as the efficacy of a bioherbicide candidate is generally more sensitive to environmental variation than a conventional herbicide. Common themes and lessons emerging from the available literature in regard to this challenge are presented. Additionally, future directions for this crop protection strategy are suggested. PMID:26379687

  7. Purification Techniques of Bacteriocins from Lactic Acid Bacteria and Other Gram-Positive Bacteria

    Science.gov (United States)

    Saavedra, Lucila; Sesma, Fernando

    The search for new antimicrobial peptides produced by lactic acid ­bacteria and other Gram-positive microorganisms has become an interesting field of research in the past decades. The fact that bacteriocins are active against numerous foodborne and human pathogens, are produced by generally regarded as safe (GRAS) microorganisms, and are readily degraded by proteolytic host systems makes them attractive candidates for biotechnological applications. However, before suggesting or choosing a new bacteriocin for future technology developments, it is necessary to elucidate its biochemical structure and its mode of action, which may be carried out once the bacteriocin is purified to homogeneity. This chapter focuses on describing the main strategies used for the purification of numerous bacteriocins.

  8. A direct pre-screen for marine bacteria producing compounds inhibiting quorum sensing reveals diverse planktonic bacteria that are bioactive.

    Science.gov (United States)

    Linthorne, Jamie S; Chang, Barbara J; Flematti, Gavin R; Ghisalberti, Emilio L; Sutton, David C

    2015-02-01

    A promising new strategy in antibacterial research is inhibition of the bacterial communication system termed quorum sensing. In this study, a novel and rapid pre-screening method was developed to detect the production of chemical inhibitors of this system (quorum-quenching compounds) by bacteria isolated from marine and estuarine waters. This method involves direct screening of mixed populations on an agar plate, facilitating specific isolation of bioactive colonies. The assay showed that between 4 and 46 % of culturable bacteria from various samples were bioactive, and of the 95 selectively isolated bacteria, 93.7 % inhibited Vibrio harveyi bioluminescence without inhibiting growth, indicating potential production of quorum-quenching compounds. Of the active isolates, 21 % showed further activity against quorum-sensing-regulated pigment production by Serratia marcescens. The majority of bioactive isolates were identified by 16S ribosomal DNA (rDNA) amplification and sequencing as belonging to the genera Vibrio and Pseudoalteromonas. Extracts of two strongly bioactive Pseudoalteromonas isolates (K1 and B2) were quantitatively assessed for inhibition of growth and quorum-sensing-regulated processes in V. harveyi, S. marcescens and Chromobacterium violaceum. Extracts of the isolates reduced V. harveyi bioluminescence by as much as 98 % and C. violaceum pigment production by 36 % at concentrations which had no adverse effect on growth. The activity found in the extracts indicated that the isolates may produce quorum-quenching compounds. This study further supports the suggestion that quorum quenching may be a common attribute among culturable planktonic marine and estuarine bacteria.

  9. The determination and arrangement of a combination of enzyme lactate dehydrogenase of bacteria Acinetobacter sp. as a device the identity important bacteria agent composts

    Science.gov (United States)

    Sukmawati, D.; Puspitaningrum, R.; Muzajjanah

    2017-07-01

    The number of garbage generated by the industry or society is a usual problem encountered by almost all urban centers, especially large cities such as Jakarta. Waste prevention strategy required quickly and accurately. One strategy for tackling the Junk was getting lactic acid-producing bacteria. It has been shown that lactic acid can increase the acceleration of organic matter such as an overhaul of lignin and cellulose as well as out causing toxic compounds arising from decay. This research will be conducted on the determination and characterization of the enzyme-producing compost bacteria LDH lactate dehydrogenase LDH - which in isolation from the garbage Landfill Rawasari. Methodology: Research carried out consists: isolation of lactic acid-producing bacteria; identification of microscopic, macroscopic and staining Gram; cellulose assay, and optimization of PCR conditions LDH enzymes producing bacteria. Isolation is performed by dilution method and the direct method. As many as 5-point sampling. Each stage is conducted from 10 grams of soil from the top surface of the compost. Isolation results obtained 100 isolate the bacteria. Base on the characteristic of macroscopic and microscopic observations retrieved 14 isolates of bacteria have shaped rods and brought forth a negative kind of Gram positive staining. Bacterial isolates with codes (BK1; BK3; BK4; BK5; BK6; BK7; BK8; BK9; BK10; BK11: BK12; BK 13). The potential bacteria with ability produce lactate dehydrogenase was BK1 and BK3. Base for analysis phylogenetic there was identification bacteria bak1 and bak3 where Acinetobacter sp.

  10. Endocarditis caused by anaerobic bacteria.

    Science.gov (United States)

    Kestler, M; Muñoz, P; Marín, M; Goenaga, M A; Idígoras Viedma, P; de Alarcón, A; Lepe, J A; Sousa Regueiro, D; Bravo-Ferrer, J M; Pajarón, M; Costas, C; García-López, M V; Hidalgo-Tenorio, C; Moreno, M; Bouza, E

    2017-10-01

    Infective endocarditis (IE) caused by anaerobic bacteria is a rare and poorly characterized disease. Most data reported in the literature are from case reports [1-3]. Therefore, we assessed the situation of anaerobic IE (AIE) in Spain using the database of the Spanish Collaboration on Endocarditis (GAMES). We performed a prospective study from 2008 to 2016 in 26 Spanish centers. We included 2491 consecutive cases of definite IE (Duke criteria). Anaerobic bacteria caused 22 cases (0.9%) of definite IE. Median age was 66 years (IQR, 56-73), and 19 (86.4%) patients were men. Most patients (14 [63.6%]) had prosthetic valve IE and all episodes were left-sided: aortic valves, 12 (54.5%); and mitral valves, 8 (36.4%). The most common pathogens were Propionibacterium acnes (14 [63.6%]), Lactobacillus spp (3 [13.63%]), and Clostridium spp. (2 [9.0%]), and the infection was mainly odontogenic. Fifteen of the 22 patients (68.2%) underwent cardiac surgery. Mortality was 18.2% during admission and 5.5% after 1 year of follow-up. When patients with AIE were compared with the rest of the cohort, we found that although those with AIE had a similar age and Charlson comorbidity index, they were more likely to have community-acquired IE (86.4% vs. 60.9%, p = 0.01), have undergone cardiac surgery (68.2% vs 48.7% p = 0.06), and have had lower mortality rates during admission (18.2% vs. 27.3%). IE due to anaerobic bacteria is an uncommon disease that affects mainly prosthetic valves and frequently requires surgery. Otherwise, there are no major differences between AIE and IE caused by other microorganisms. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Bacteria and vampirism in cinema.

    Science.gov (United States)

    Castel, O; Bourry, A; Thévenot, S; Burucoa, C

    2013-09-01

    A vampire is a non-dead and non-alive chimerical creature, which, according to various folklores and popular superstitions, feeds on blood of the living to draw vital force. Vampires do not reproduce by copulation, but by bite. Vampirism is thus similar to a contagious disease contracted by intravascular inoculation with a suspected microbial origin. In several vampire films, two real bacteria were staged, better integrated than others in popular imagination: Yersinia pestis and Treponema pallidum. Bacillus vampiris was created for science-fiction. These films are attempts to better define humans through one of their greatest fears: infectious disease. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  12. Global Strategy

    DEFF Research Database (Denmark)

    Li, Peter Ping

    2013-01-01

    Global strategy differs from domestic strategy in terms of content and process as well as context and structure. The content of global strategy can contain five key elements, while the process of global strategy can have six major stages. These are expounded below. Global strategy is influenced...... by rich and complementary local contexts with diverse resource pools and game rules at the national level to form a broad ecosystem at the global level. Further, global strategy dictates the interaction or balance between different entry strategies at the levels of internal and external networks....

  13. Graphene-based wireless bacteria detection on tooth enamel

    Science.gov (United States)

    Mannoor, Manu S.; Tao, Hu; Clayton, Jefferson D.; Sengupta, Amartya; Kaplan, David L.; Naik, Rajesh R.; Verma, Naveen; Omenetto, Fiorenzo G.; McAlpine, Michael C.

    2012-03-01

    Direct interfacing of nanosensors onto biomaterials could impact health quality monitoring and adaptive threat detection. Graphene is capable of highly sensitive analyte detection due to its nanoscale nature. Here we show that graphene can be printed onto water-soluble silk. This in turn permits intimate biotransfer of graphene nanosensors onto biomaterials, including tooth enamel. The result is a fully biointerfaced sensing platform, which can be tuned to detect target analytes. For example, via self-assembly of antimicrobial peptides onto graphene, we show bioselective detection of bacteria at single-cell levels. Incorporation of a resonant coil eliminates the need for onboard power and external connections. Combining these elements yields two-tiered interfacing of peptide-graphene nanosensors with biomaterials. In particular, we demonstrate integration onto a tooth for remote monitoring of respiration and bacteria detection in saliva. Overall, this strategy of interfacing graphene nanosensors with biomaterials represents a versatile approach for ubiquitous detection of biochemical targets.

  14. Oral Anaerobic Bacteria in the Etiology of Ankylosing Spondylitis

    Directory of Open Access Journals (Sweden)

    Mesut Öğrendik

    2017-06-01

    Full Text Available Ankylosing spondylitis (AS is associated with periodontitis. Anti– Porphyromonas gingivalis and anti– Prevotella intermedia antibody titers were higher in patients with spondyloarthritis than in healthy people. Sulfasalazine is an effective antibiotic treatment for AS. Moxifloxacin and rifamycin were also found to be significantly effective. The etiology hypothesis suggests that oral anaerobic bacteria such as Porphyromonas spp and Prevotella spp contribute to the disease. These bacteria have been identified in AS, and we will discuss their pathogenic properties with respect to our knowledge of the disease. Periodontal pathogens are likely to be responsible for the development of AS in genetically susceptible individuals. This finding should guide the development of more comprehensive and efficacious treatment strategies for AS.

  15. Subversion of inflammasome activation and pyroptosis by pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Larissa D Cunha

    2013-11-01

    Full Text Available Activation of the inflammasome occurs in response to a notably high number of pathogenic microbes and is a broad innate immune response that effectively contributes to restriction of pathogen replication and generation of adaptive immunity. Activation of these platforms leads to caspase-1- and/or caspase-11-dependent secretion of proteins, including cytokines, and induction of a specific form of cell death called pyroptosis, which directly or indirectly contribute for restriction of pathogen replication. Not surprisingly, bona fide intracellular pathogens developed strategies for manipulation of cell death to guarantee intracellular replication. In this sense, the remarkable advances in the knowledge of the inflammasome field have been accompanied by several reports characterizing the inhibition of this platform by several pathogenic bacteria. Herein, we review some processes used by pathogenic bacteria, including Yersinia spp., Pseudomonas aeruginosa, Vibrio parahaemolyticus, Chlamydia trachomatis, Francisella tularensis, Shigella flexneri, Legionella pneumophila and Coxiella burnetii to evade the activation of the inflammasome and the induction of pyroptosis.

  16. Probiotic Bacteria Induce a ‘Glow of Health’

    Science.gov (United States)

    Smillie, Christopher; Varian, Bernard J.; Ibrahim, Yassin M.; Lakritz, Jessica R.; Alm, Eric J.; Erdman, Susan E.

    2013-01-01

    Radiant skin and hair are universally recognized as indications of good health. However, this ‘glow of health’ display remains poorly understood. We found that feeding of probiotic bacteria to aged mice induced integumentary changes mimicking peak health and reproductive fitness characteristic of much younger animals. Eating probiotic yogurt triggered epithelial follicular anagen-phase shift with sebocytogenesis resulting in thick lustrous fur due to a bacteria-triggered interleukin-10-dependent mechanism. Aged male animals eating probiotics exhibited increased subcuticular folliculogenesis, when compared with matched controls, yielding luxuriant fur only in probiotic-fed subjects. Female animals displayed probiotic-induced hyperacidity coinciding with shinier hair, a feature that also aligns with fertility in human females. Together these data provide insights into mammalian evolution and novel strategies for integumentary health. PMID:23342023

  17. 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.

  18. Money and transmission of bacteria.

    Science.gov (United States)

    Gedik, Habip; Voss, Timothy A; Voss, Andreas

    2013-08-28

    Money is one of the most frequently passed items in the world. The aim of this study was to ascertain the survival status of bacteria including Staphylococcus aureus, Escherichia coli, and Vancomycin- Resistant Enterococci (VRE) on banknotes from different countries and the transmission of bacteria to people who come in contact with the banknotes. The survival rate was highest for the Romanian Leu yielding all three microorganisms used after both three and six hours of drying. Furthermore, the Leu was the only banknote to yield VRE after one day of drying. Other currencies either enabled the survival of Extended-Spectrum Beta-Lactamases (ESBL) and VRE (e.g. Euro), but not of MRSA, or the other way round (e.g. US Dollar). While a variety of factors such as community hygiene levels, people's behaviour, and antimicrobial resistance rates at community level obviously have influence on the transmission of resistant microorganisms, the type of banknote-paper may be an additional variable to consider.

  19. Resistance of Bacteria to Biocides.

    Science.gov (United States)

    Maillard, Jean-Yves

    2018-04-01

    Biocides and formulated biocides are used worldwide for an increasing number of applications despite tightening regulations in Europe and in the United States. One concern is that such intense usage of biocides could lead to increased bacterial resistance to a product and cross-resistance to unrelated antimicrobials including chemotherapeutic antibiotics. Evidence to justify such a concern comes mostly from the use of health care-relevant bacterial isolates, although the number of studies of the resistance characteristics of veterinary isolates to biocides have increased the past few years. One problem remains the definition of "resistance" and how to measure resistance to a biocide. This has yet to be addressed globally, although the measurement of resistance is becoming more pressing, with regulators both in Europe and in the United States demanding that manufacturers provide evidence that their biocidal products will not impact on bacterial resistance. Alongside in vitro evidence of potential antimicrobial cross-resistance following biocide exposure, our understanding of the mechanisms of bacterial resistance and, more recently, our understanding of the effect of biocides to induce a mechanism(s) of resistance in bacteria has improved. This article aims to provide an understanding of the development of antimicrobial resistance in bacteria following a biocide exposure. The sections provide evidence of the occurrence of bacterial resistance and its mechanisms of action and debate how to measure bacterial resistance to biocides. Examples pertinent to the veterinary field are used where appropriate.

  20. Differential scanning calorimetry of bacteria.

    Science.gov (United States)

    Miles, C A; Mackey, B M; Parsons, S E

    1986-04-01

    Thermograms obtained by differential scanning calorimetry of a range of bacteria of different heat resistances were compared. Equations were derived to calculate the rate at which the numbers of viable organisms in a calorimeter decline as the temperature is raised at a constant rate. Vegetative bacteria scanned at 10 degrees C min-1 showed multi-peaked thermograms with four major peaks (denoted m, n, p and q) occurring in the regions 68-73, 77-84, 89-99 and 105-110 degrees C respectively. Exceptions were that peak m (the largest peak) occurred at 79-82 degrees C in Bacillus stearothermophilus and an additional peak, r, was detected in Escherichia coli at 119 degrees C. At temperatures below the main peak m there were major differences in thermograms between species. There was a direct relationship between the onset of thermal denaturation and the thermoresistance of different organisms. Heat-sensitive organisms displayed thermogram features which were absent in the more heat-resistant types. When samples were cooled to 5 degrees C and re-heated, a small endothermic peak, pr, was observed at the same temperature as p. Peaks p and pr were identified as the melting endotherms of DNA. In all vegetative organisms examined, maximum death rates, computed from published D and z values, occurred at temperatures above the onset of thermal denaturation, i.e. cell death and irreversible denaturation of cell components occurred within the same temperature range.

  1. Constitutive and regulated expression vectors to construct polyphosphate deficient bacteria

    Directory of Open Access Journals (Sweden)

    Jerez Carlos A

    2009-03-01

    Full Text Available Abstract Background Inorganic polyphosphate (polyP, a polymer of tens or hundreds of phosphate residues linked by ATP-like bonds, is found in all organisms and performs a wide variety of functions. PolyP is synthesized in bacterial cells by the actions of polyphosphate kinases (PPK1 and PPK2 and degraded by an exopolyphosphatase (PPX. Bacterial cells with polyP deficiencies are impaired in many structural and important cellular functions such as motility, quorum sensing, biofilm formation and virulence. Knockout mutants of the ppk1 gene have been the most frequent strategy employed to generate polyP deficient cells. Results As an alternative method to construct polyP-deficient bacteria we developed constitutive and regulated broad-host-range vectors for depleting the cellular polyP content. This was achieved by the overexpression of yeast exopolyphosphatase (PPX1. Using this approach in a polyphosphate accumulating bacteria (Pseudomonas sp. B4, we were able to eliminate most of the cellular polyP (>95%. Furthermore, the effect of overexpression of PPX1 resembled the functional defects found in motility and biofilm formation in a ppk1 mutant from Pseudomonas aeruginosa PAO1. The plasmids constructed were also successfully replicated in other bacteria such as Escherichia coli, Burkholderia and Salmonella. Conclusion To deplete polyP contents in bacteria broad-host-range expression vectors can be used as an alternative and more efficient method compared with the deletion of ppk genes. It is of great importance to understand why polyP deficiency affects vital cellular processes in bacteria. The construction reported in this work will be of great relevance to study the role of polyP in microorganisms with non-sequenced genomes or those in which orthologs to ppk genes have not been identified.

  2. Aging in bacteria, immortality or not-a critical review.

    Science.gov (United States)

    Gómez, José M G

    2010-12-01

    Bacteria were traditionally thought to have a symmetrical binary fission without a clear distinction between soma and germ-line, being thus considered as immortal biological entities. Yet it has been recently described that bacteria also undergo replicative aging (RA). That is, they exhibit finite replicative abilities under good conditions to growth. The apparently initial indistinguishability of sibling cells after cytokinesis is broken. After division, the daughter cell that inherits the "old" pole present in the "mother cell" progressively exhibits a decline in its proliferative capacity with increasing cell pole age. This is a clear hallmark and phenotypic manifestation of a bona fide RA phenomenon in toto. While the exact molecular mechanism(s) underlying to this lost of replicative potential are not yet fully understood, the "old pole cell" is considered as an aging parent that in a repeatedly manner is able to produce rejuvenated offspring which inherit a resetting of the biological clock. On the order hand, bacteria exhibit in addition to this "mandatory" RA the dubbed conditional senescence (CS). CS is defined as a decline in cellular viability observed in arrested-growing bacteria populations, a phenomenon apparently not related to RA under growing active conditions. To understand bacterial aging, it is necessary to put it within the sociality-multicellularity framework. This is a new conceptual paradigm that expresses the natural reality of the bacterial world. From this more ecological perspective these bacterial aging phenomena probably should represent an insurance/bethedging anticipative survival strategy. This is underpinned in a self-generation of an appropriate level of populational phenotypic diversity. That is, bacterial aging could be considered a communitarian adaptive response to cope with different environmental stresses and threats. I have highlighted the necessity to construct an integrative conceptual framework to achieve a unified view

  3. Biofilms: Community Behavior by Bacteria

    Indian Academy of Sciences (India)

    IAS Admin

    United we stand, divided we fall. This is a ... controls biofilm development, swarming motility and the produc- ... thought that the absence of overt gut flora upsets the balance .... there are several risks of integration which makes this strategy.

  4. Towards lactic acid bacteria-based biorefineries.

    Science.gov (United States)

    Mazzoli, Roberto; Bosco, Francesca; Mizrahi, Itzhak; Bayer, Edward A; Pessione, Enrica

    2014-11-15

    Lactic acid bacteria (LAB) have long been used in industrial applications mainly as starters for food fermentation or as biocontrol agents or as probiotics. However, LAB possess several characteristics that render them among the most promising candidates for use in future biorefineries in converting plant-derived biomass-either from dedicated crops or from municipal/industrial solid wastes-into biofuels and high value-added products. Lactic acid, their main fermentation product, is an attractive building block extensively used by the chemical industry, owing to the potential for production of polylactides as biodegradable and biocompatible plastic alternative to polymers derived from petrochemicals. LA is but one of many high-value compounds which can be produced by LAB fermentation, which also include biofuels such as ethanol and butanol, biodegradable plastic polymers, exopolysaccharides, antimicrobial agents, health-promoting substances and nutraceuticals. Furthermore, several LAB strains have ascertained probiotic properties, and their biomass can be considered a high-value product. The present contribution aims to provide an extensive overview of the main industrial applications of LAB and future perspectives concerning their utilization in biorefineries. Strategies will be described in detail for developing LAB strains with broader substrate metabolic capacity for fermentation of cheaper biomass. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Sulfur metabolism in phototrophic sulfur bacteria

    DEFF Research Database (Denmark)

    Frigaard, Niels-Ulrik; Dahl, Christiane

    2008-01-01

    Phototrophic sulfur bacteria are characterized by oxidizing various inorganic sulfur compounds for use as electron donors in carbon dioxide fixation during anoxygenic photosynthetic growth. These bacteria are divided into the purple sulfur bacteria (PSB) and the green sulfur bacteria (GSB......). They utilize various combinations of sulfide, elemental sulfur, and thiosulfate and sometimes also ferrous iron and hydrogen as electron donors. This review focuses on the dissimilatory and assimilatory metabolism of inorganic sulfur compounds in these bacteria and also briefly discusses these metabolisms...... in other types of anoxygenic phototrophic bacteria. The biochemistry and genetics of sulfur compound oxidation in PSB and GSB are described in detail. A variety of enzymes catalyzing sulfur oxidation reactions have been isolated from GSB and PSB (especially Allochromatium vinosum, a representative...

  6. Bactericide for sulfate-reducing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Shklyar, T F; Anoshina, G M; Blokhin, V Ye; Kisarrev, Ye L; Novikovsa, G M

    1981-01-01

    The aim of the invention is to find a bactericide for sulfate-reducing bacteria of oil fields in Western Siberia in order to suppress the biocorrosive activity on oil industry equipment. This goal is achieved by using M-nitroacetanylide as the bactericide of sulfate-reducing bacteria. This agent suppresses the activity of a stored culture of sulfate-reducing bacteria that comes from industrial waste waters injection wells of the Smotlor oil field.

  7. Differential staining of bacteria: acid fast stain.

    Science.gov (United States)

    Reynolds, Jackie; Moyes, Rita B; Breakwell, Donald P

    2009-11-01

    Acid-fastness is an uncommon characteristic shared by the genera Mycobacterium (Section 10A) and Nocardia. Because of this feature, this stain is extremely helpful in identification of these bacteria. Although Gram positive, acid-fast bacteria do not take the crystal violet into the wall well, appearing very light purple rather than the deep purple of normal Gram-positive bacteria. (c) 2009 by John Wiley & Sons, Inc.

  8. Transformation of gram positive bacteria by sonoporation

    Science.gov (United States)

    Yang, Yunfeng; Li, Yongchao

    2014-03-11

    The present invention provides a sonoporation-based method that can be universally applied for delivery of compounds into Gram positive bacteria. Gram positive bacteria which can be transformed by sonoporation include, for example, Bacillus, Streptococcus, Acetobacterium, and Clostridium. Compounds which can be delivered into Gram positive bacteria via sonoporation include nucleic acids (DNA or RNA), proteins, lipids, carbohydrates, viruses, small organic and inorganic molecules, and nano-particles.

  9. Magnetotactic bacteria at the geomagnetic equator

    International Nuclear Information System (INIS)

    Frankel, R.B.; Blakemore, R.P.; Araujo, F.F.T. de; Esquivel, D.M.S.; Danon, J.

    1981-01-01

    Magnetotatic bacteria are observed in freshwater and marine sediments of Fortaleza, Brazil, situated close to the geomagnetic equator. Both South-seeking and North-seeking bacteria are present in roughly equal numbers in the same samples. This observation is consistent with the hypothesis that the vertical component of the geomagnetic field selects the predominant polarity type among magnetotactic bacteria in natural environments. (Author) [pt

  10. Statistical signatures of a targeted search by bacteria

    Science.gov (United States)

    Jashnsaz, Hossein; Anderson, Gregory G.; Pressé, Steve

    2017-12-01

    Chemoattractant gradients are rarely well-controlled in nature and recent attention has turned to bacterial chemotaxis toward typical bacterial food sources such as food patches or even bacterial prey. In environments with localized food sources reminiscent of a bacterium’s natural habitat, striking phenomena—such as the volcano effect or banding—have been predicted or expected to emerge from chemotactic models. However, in practice, from limited bacterial trajectory data it is difficult to distinguish targeted searches from an untargeted search strategy for food sources. Here we use a theoretical model to identify statistical signatures of a targeted search toward point food sources, such as prey. Our model is constructed on the basis that bacteria use temporal comparisons to bias their random walk, exhibit finite memory and are subject to random (Brownian) motion as well as signaling noise. The advantage with using a stochastic model-based approach is that a stochastic model may be parametrized from individual stochastic bacterial trajectories but may then be used to generate a very large number of simulated trajectories to explore average behaviors obtained from stochastic search strategies. For example, our model predicts that a bacterium’s diffusion coefficient increases as it approaches the point source and that, in the presence of multiple sources, bacteria may take substantially longer to locate their first source giving the impression of an untargeted search strategy.

  11. Bioenergetics of photoheterotrophic bacteria in the oceans.

    Science.gov (United States)

    Kirchman, David L; Hanson, Thomas E

    2013-04-01

    Photoheterotrophic microbes, such as proteorhodopsin (PR)-based phototrophic (PRP) and aerobic anoxygenic phototrophic (AAP) bacteria, are well known to be abundant in the oceans, potentially playing unique roles in biogeochemical cycles. However, the contribution of phototrophy to the energy requirements of these bacteria has not been quantitatively examined to date. To better understand the implications of photoheterophy in the oceans, we calculated energy benefits and costs of phototrophy and compared net benefits with maintenance costs. Benefits depend on the number of photosynthetic units (PSUs), absorption cross-section area of each PSU as function of wavelength, the in situ light quality, and the energy yield per absorbed photon. For costs we considered the energy required for the synthesis of pigments, amino acids and proteins in each PSU. Our calculations indicate that AAP bacteria harvest more light energy than do PRP bacteria, but the costs of phototrophy are much higher for AAP bacteria. Still, the net energy gained by AAP bacteria is often sufficient to meet maintenance costs, while that is not the case for PRP bacteria except with high light intensities and large numbers of proteorhodopsin molecules per cell. The low costs and simplicity of PR-based phototrophy explain the high abundance of proteorhodopsin genes in the oceans. However, even for AAP bacteria, the net energy yield of phototrophy is apparently too low to influence the distribution of photoheterotrophic bacteria among various marine systems. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

  12. Quorum sensing in gram-negative bacteria

    DEFF Research Database (Denmark)

    Wu, H.; Song, Z.J.; Høiby, N.

    2004-01-01

    Bacteria can communicate with each other by means of signal molecules to coordinate the behavior of the entire community, and the mechanism is referred to as quorum sensing (QS). Signal systems enable bacteria to sense the size of their densities by monitoring the concentration of the signal...... molecules. Among Gram-negative bacteria N-acyl-L-homoserine lactone (acyl-HSL)-dependent quorum sensing systems are particularly widespread. These systems are used to coordinate expression of phenotypes that are fundamental to the interaction of bacteria with each other and with their environment...

  13. Isolation and characterization of methanogenic bacteria from ...

    African Journals Online (AJOL)

    Isolation and characterization of methanogenic bacteria from brewery wastewater in Kenya. Sylvia Injete Murunga, Duncan Onyango Mbuge, Ayub Njoroge Gitau, Urbanus Ndungwa Mutwiwa, Ingrid Namae Wekesa ...

  14. Fewer bacteria in warm water

    International Nuclear Information System (INIS)

    Bagh, Lene

    1999-01-01

    There has been many suggestions to how the ideal warm water system should be. Particularly whether warm water containers or heat exchangers in larger houses are the best solutions in order to maintain a water quality with low levels of bacteria. In an investigation made by Statens Byggeforskningsinstitutt (Denmark) regarding ''Bacterial growth in warm water installations with heat exchangers'' there were used several heat exchangers made by Gjelsted and Lund of three of which had HWAT heating cables. The bacterial content was low from these exchangers compared to exchangers with circulation. The article presents promising results from a study where the method was investigated over a longer period in two new larger warm water systems. Some energy conservation aspects are discussed

  15. Modeling Political Populations with Bacteria

    Science.gov (United States)

    Cleveland, Chris; Liao, David

    2011-03-01

    Results from lattice-based simulations of micro-environments with heterogeneous nutrient resources reveal that competition between wild-type and GASP rpoS819 strains of E. Coli offers mutual benefit, particularly in nutrient deprived regions. Our computational model spatially maps bacteria populations and energy sources onto a set of 3D lattices that collectively resemble the topology of North America. By implementing Wright-Fishcer re- production into a probabilistic leap-frog scheme, we observe populations of wild-type and GASP rpoS819 cells compete for resources and, yet, aid each other's long term survival. The connection to how spatial political ideologies map in a similar way is discussed.

  16. Cell Size Regulation in Bacteria

    Science.gov (United States)

    Amir, Ariel

    2014-05-01

    Various bacteria such as the canonical gram negative Escherichia coli or the well-studied gram positive Bacillus subtilis divide symmetrically after they approximately double their volume. Their size at division is not constant, but is typically distributed over a narrow range. Here, we propose an analytically tractable model for cell size control, and calculate the cell size and interdivision time distributions, as well as the correlations between these variables. We suggest ways of extracting the model parameters from experimental data, and show that existing data for E. coli supports partial size control, and a particular explanation: a cell attempts to add a constant volume from the time of initiation of DNA replication to the next initiation event. This hypothesis accounts for the experimentally observed correlations between mother and daughter cells as well as the exponential dependence of size on growth rate.

  17. Antioxidant Properties of Probiotic Bacteria.

    Science.gov (United States)

    Wang, Yang; Wu, Yanping; Wang, Yuanyuan; Xu, Han; Mei, Xiaoqiang; Yu, Dongyou; Wang, Yibing; Li, Weifen

    2017-05-19

    Oxidative stress defines a condition in which the prooxidant-antioxidant balance in the cell is disturbed, resulting in DNA hydroxylation, protein denaturation, lipid peroxidation, and apoptosis, ultimately compromising cells' viability. Probiotics have been known for many beneficial health effects, and the consumption of probiotics alone or in food shows that strain-specific probiotics can present antioxidant activity and reduce damages caused by oxidation. However, the oxidation-resistant ability of probiotics, especially the underling mechanisms, is not properly understood. In this view, there is interest to figure out the antioxidant property of probiotics and summarize the mode of action of probiotic bacteria in antioxidation. Therefore, in the present paper, the antioxidant mechanisms of probiotics have been reviewed in terms of their ability to improve the antioxidant system and their ability to decrease radical generation. Since in recent years, oxidative stress has been associated with an altered gut microbiota, the effects of probiotics on intestinal flora composition are also elaborated.

  18. Engineering nanoparticle-coated bacteria as oral DNA vaccines for cancer immunotherapy.

    Science.gov (United States)

    Hu, Qinglian; Wu, Min; Fang, Chun; Cheng, Changyong; Zhao, Mengmeng; Fang, Weihuan; Chu, Paul K; Ping, Yuan; Tang, Guping

    2015-04-08

    Live attenuated bacteria are of increasing importance in biotechnology and medicine in the emerging field of cancer immunotherapy. Oral DNA vaccination mediated by live attenuated bacteria often suffers from low infection efficiency due to various biological barriers during the infection process. To this end, we herein report, for the first time, a new strategy to engineer cationic nanoparticle-coated bacterial vectors that can efficiently deliver oral DNA vaccine for efficacious cancer immunotherapy. By coating live attenuated bacteria with synthetic nanoparticles self-assembled from cationic polymers and plasmid DNA, the protective nanoparticle coating layer is able to facilitate bacteria to effectively escape phagosomes, significantly enhance the acid tolerance of bacteria in stomach and intestines, and greatly promote dissemination of bacteria into blood circulation after oral administration. Most importantly, oral delivery of DNA vaccines encoding autologous vascular endothelial growth factor receptor 2 (VEGFR2) by this hybrid vector showed remarkable T cell activation and cytokine production. Successful inhibition of tumor growth was also achieved by efficient oral delivery of VEGFR2 with nanoparticle-coated bacterial vectors due to angiogenesis suppression in the tumor vasculature and tumor necrosis. This proof-of-concept work demonstrates that coating live bacterial cells with synthetic nanoparticles represents a promising strategy to engineer efficient and versatile DNA vaccines for the era of immunotherapy.

  19. Sterol Synthesis in Diverse Bacteria.

    Science.gov (United States)

    Wei, Jeremy H; Yin, Xinchi; Welander, Paula V

    2016-01-01

    Sterols are essential components of eukaryotic cells whose biosynthesis and function has been studied extensively. Sterols are also recognized as the diagenetic precursors of steranes preserved in sedimentary rocks where they can function as geological proxies for eukaryotic organisms and/or aerobic metabolisms and environments. However, production of these lipids is not restricted to the eukaryotic domain as a few bacterial species also synthesize sterols. Phylogenomic studies have identified genes encoding homologs of sterol biosynthesis proteins in the genomes of several additional species, indicating that sterol production may be more widespread in the bacterial domain than previously thought. Although the occurrence of sterol synthesis genes in a genome indicates the potential for sterol production, it provides neither conclusive evidence of sterol synthesis nor information about the composition and abundance of basic and modified sterols that are actually being produced. Here, we coupled bioinformatics with lipid analyses to investigate the scope of bacterial sterol production. We identified oxidosqualene cyclase (Osc), which catalyzes the initial cyclization of oxidosqualene to the basic sterol structure, in 34 bacterial genomes from five phyla (Bacteroidetes, Cyanobacteria, Planctomycetes, Proteobacteria, and Verrucomicrobia) and in 176 metagenomes. Our data indicate that bacterial sterol synthesis likely occurs in diverse organisms and environments and also provides evidence that there are as yet uncultured groups of bacterial sterol producers. Phylogenetic analysis of bacterial and eukaryotic Osc sequences confirmed a complex evolutionary history of sterol synthesis in this domain. Finally, we characterized the lipids produced by Osc-containing bacteria and found that we could generally predict the ability to synthesize sterols. However, predicting the final modified sterol based on our current knowledge of sterol synthesis was difficult. Some bacteria

  20. Characterization of Bacteria Isolation of Bacteria from Pinyon Rhizosphere,

    Science.gov (United States)

    2016-01-01

    Two hundred and fifty bacterial strains were isolated from pinyon rhizosphere and screened for biosurfactants production. Among them, six bacterial strains were selected for their potential to produce biosurfactants using two low cost wastes, crude glycerol and lactoserum, as raw material. Both wastes were useful for producing biosurfactants because of their high content in fat and carbohydrates. The six strains were identified by 16S rDNA with an identity percentage higher than 95%, three strains belonged to Enterobacter sp., Pseudomonas aeruginosa, Bacillus pumilus and Rhizobium sp. All strains assayed were able to grow and showed halos around the colonies as evidence of biosurfactants production on Cetyl Trimethyl Ammonium Bromide agar with crude glycerol and lactoserum as substrate. In a mineral salt liquid medium enriched with both wastes, the biosurfactants were produced and collected from free cell medium after 72 h incubation. The biosurfactants produced reduced the surface tension from 69 to 30 mN/m with an emulsification index of diesel at approximately 60%. The results suggest that biosurfactants produced by rhizosphere bacteria from pinyon have promising environmental applications.

  1. Identification of New Aflatoxin B1-Degrading Bacteria from Iran

    Directory of Open Access Journals (Sweden)

    Fahimeh Sangi

    2018-04-01

    Full Text Available Background: Aflatoxin B1 (AFB1 is a mutagenic and carcinogenic compound mainly produced by the Aspergillus parasiticus, A. flavus, A. nomius, A. tamari, and A. pseudotamarii. AFB1 biodegradation is the most important strategy for reducing AFB1 in plant tissues. Bacteria can deactivate and biodegrade AFB1 for effective detoxification of contaminated products. The present study investigated the efficiency of AFB1 degradation by soil bacteria from the Southern Khorasan Province in Eastern Iran by thin-layer and high-performance liquid chromatography during 2014–2015. Methods: DNA was extracted from AFB1-degrading isolates by the cetyltrimethylammonium bromide method and the 16S rRNA gene was amplified with the 27f and 1492r general bacterial primers and the sequences were used to identify the isolates based on their similarity to Gene Bank sequences of known bacterial species. Results: We isolated five strains from four species of AFB1-degrading bacteria from Birjand plain, including Bacillus pumilus, two isolates of Ochrobactrum pseudogrigonens, Pseudomonas aeruginosa, and Enterobacter cloace, which had AFB1-degrading activities of 88%, 78%, 61%, 58%, and 51%, respectively. Conclusion: We provide the first demonstration of AFB1 degradation by B. pumilus in from Iran and the first report identifying O. pseudogrigonens and E. cloace species as having AFB1-degrading activity.

  2. Modulation of host responses by oral commensal bacteria

    Directory of Open Access Journals (Sweden)

    Deirdre A. Devine

    2015-02-01

    Full Text Available Immunomodulatory commensal bacteria are proposed to be essential for maintaining healthy tissues, having multiple roles including priming immune responses to ensure rapid and efficient defences against pathogens. The default state of oral tissues, like the gut, is one of inflammation which may be balanced by regulatory mechanisms and the activities of anti-inflammatory resident bacteria that modulate Toll-like receptor (TLR signalling or NF-κB activation, or influence the development and activities of immune cells. However, the widespread ability of normal resident organisms to suppress inflammation could impose an unsustainable burden on the immune system and compromise responses to pathogens. Immunosuppressive resident bacteria have been isolated from the mouth and, for example, may constitute 30% of the resident streptococci in plaque or on the tongue. Their roles in oral health and dysbiosis remain to be determined. A wide range of bacterial components and/or products can mediate immunomodulatory activity, raising the possibility of development of alternative strategies for therapy and health promotion using probiotics, prebiotics, or commensal-derived immunomodulatory molecules.

  3. Quorum Quenching in Culturable Phyllosphere Bacteria from Tobacco

    Directory of Open Access Journals (Sweden)

    Guoqiang Zhuang

    2013-07-01

    Full Text Available Many Gram-negative plant pathogenic bacteria employ a N-acylhomoserine lactone (AHL-based quorum sensing (QS system to regulate their virulence traits. A sustainable biocontrol strategy has been developed using quorum quenching (QQ bacteria to interfere with QS and protect plants from pathogens. Here, the prevalence and the diversity of QQ strains inhabiting tobacco leaf surfaces were explored. A total of 1177 leaf-associated isolates were screened for their ability to disrupt AHL-mediated QS, using the biosensor Chromobacterium violaceum CV026. One hundred and sixty-eight strains (14% are capable of interfering with AHL activity. Among these, 106 strains (63% of the culturable quenchers can enzymatically degrade AHL molecules, while the remaining strains might use other QS inhibitors to interrupt the chemical communication. Moreover, almost 79% of the QQ strains capable of inactivating AHLs enzymatically have lactonase activity. Further phylogenetic analysis based on 16S rDNA revealed that the leaf-associated QQ bacteria can be classified as Bacillus sp., Acinetobacter sp., Lysinibacillus sp., Serratia sp., Pseudomonas sp., and Myroides sp. The naturally occurring diversity of bacterial quenchers might provide opportunities to use them as effective biocontrol reagents for suppressing plant pathogen in situ.

  4. Production of Remedial Proteins through Genetically Modified Bacteria

    Directory of Open Access Journals (Sweden)

    Fatima Tariq

    2018-02-01

    Full Text Available Recombinant DNA technology has created biological organisms with advanced genetic sequences and has been extensively used to express multiple genes for therapeutic purposes when expressed in a suitable host. Microbial systems such as prokaryotic bacteria has been successfully utilized as a heterologous systems showing high therapeutic potency for various human diseases. Bioengineered bacteria have been successfully utilized for producing therapeutic proteins, treating infectious diseases, and disease arise due to increasing resistance to antibiotics. Prominently E. coli found to be the most widely used expression system for recombinant therapeutic protein production i.e. hormones, enzymes and antibodies. Besides E. coli, non-pathogenic lactic acid bacteria has also been considered as an excellent candidate for live mucosal vaccine. Likewise, S. typhimurium has been deployed as attenuated type of vaccination as well as in treatment strategy of various cancers due to its ability of wide progression in tumors. The present article is a summarized view of the main achievements and current developments in the field of recombinant therapeutics using bacterial strains focusing on their usability in therapeutics and future potential.

  5. Anti-Quorum Sensing Potential of Potato Rhizospheric Bacteria

    Directory of Open Access Journals (Sweden)

    Adeleh Sobhanipour

    2017-01-01

    Full Text Available The occurrence of antibiotic-resistant pathogenic bacteria is becoming a serious problem. The rise of multiresistance strains has forced the pharmaceutical industry to come up with new generation of more effective and potent antibiotics, therefore creating development of antivirulence compounds. Due to extensive usage of cell-to-cell bacterial communication (QS systems to monitor the production of virulence factors, disruption of QS system results in creation of a promising strategy for the control of bacterial infection. Numerous natural quorum quenching (QQ agents have been identified. In addition, many microorganisms are capable of producing smaller molecular QS inhibitors and/or macromolecular QQ enzymes. In present survey, anti QS activity of 1280 rhizosphere bacteria was assessed using the Pectobacterium carotovorum as AHL-donor and Chromobacterium violaceum CV026 as biosensor system. The results showed that 61 strains had highly AHL-degrading activity. Both Lux I and Lux R activity were affected by some isolates, suggesting that the rhizobacteria target both QS signal and receptor. These soil microorganisms with their anti-QS activity have the potential to be novel therapeutic agents for reducing virulence and pathogenicity of antibiotic resistant bacteria.

  6. Characterization of (per)chlorate-reducing bacteria

    NARCIS (Netherlands)

    Wolterink, A.F.W.M.

    2004-01-01

    Some bacteria can use (per)chlorateas terminal electron acceptor for growth. These bacteria convert perchlorate via chlorate and chlorite into chloride and molecular oxygen. Oxygen formation in microbial respiration is unique. In this study two chlorate-reducing strains

  7. Rapid methods for detection of bacteria

    DEFF Research Database (Denmark)

    Corfitzen, Charlotte B.; Andersen, B.Ø.; Miller, M.

    2006-01-01

    Traditional methods for detection of bacteria in drinking water e.g. Heterotrophic Plate Counts (HPC) or Most Probable Number (MNP) take 48-72 hours to give the result. New rapid methods for detection of bacteria are needed to protect the consumers against contaminations. Two rapid methods...

  8. Rock-degrading endophytic bacteria in cacti

    Science.gov (United States)

    M. Esther Puente; Ching Y. Li; Yoav Bashan

    2009-01-01

    A plant-bacterium association of the cardon cactus (Pachycereus pringlei) and endophytic bacteria promotes establishment of seedlings and growth on igneous rocks without soil. These bacteria weather several rock types and minerals, unbind significant amounts of useful minerals for plants from the rocks, fix in vitro N2. produce...

  9. Comparative Genomics of Green Sulfur Bacteria

    DEFF Research Database (Denmark)

    Ussery, David; Davenport, C; Tümmler, B

    2010-01-01

    Eleven completely sequenced Chlorobi genomes were compared in oligonucleotide usage, gene contents, and synteny. The green sulfur bacteria (GSB) are equipped with a core genome that sustains their anoxygenic phototrophic lifestyle by photosynthesis, sulfur oxidation, and CO(2) fixation. Whole...... weight of 10(6), and are probably instrumental for the bacteria to generate their own intimate (micro)environment....

  10. Analyzing Arthropods for the Presence of Bacteria

    OpenAIRE

    Andrews, Elizabeth S.

    2013-01-01

    Bacteria within arthropods can be identified using culture-independent methods. This unit describes protocols for surface sterilization of arthropods, DNA extraction of whole bodies and tissues, touchdown PCR amplification using 16S rDNA general bacteria primers and profiling the bacterial community using denaturing gradient gel electrophoresis.

  11. Resuscitation effects of catalase on airborne bacteria.

    OpenAIRE

    Marthi, B; Shaffer, B T; Lighthart, B; Ganio, L

    1991-01-01

    Catalase incorporation into enumeration media caused a significant increase (greater than 63%) in the colony-forming abilities of airborne bacteria. Incubation for 30 to 60 min of airborne bacteria in collection fluid containing catalase caused a greater than 95% increase in colony-forming ability. However, catalase did not have any effects on enumeration at high relative humidities (80 to 90%).

  12. Catabolism of lysine by mixed rumen bacteria

    International Nuclear Information System (INIS)

    Onodera, Ryoji; Kandatsu, Makoto.

    1975-01-01

    Metabolites arising from the catabolism of lysine by the mixed rumen bacteria were chromatographically examined by using radioactive lysine. After 6 hr incubation, 241 nmole/ml of lysine was decomposed to give ether-soluble substances and CO 2 by the bacteria and 90 nmole/ml of lysine was incorporated unchanged into the bacteria. delta-Aminovalerate, cadaverine or pipecolate did not seem to be produced from lysine even after incubation of the bacteria with addition of those three amino compounds to trap besides lysine and radioactive lysine. Most of the ether-soluble substances produced from radioactive lysine was volatile fatty acids (VFAs). Fractionation of VFAs revealed that the peaks of butyric and acetic acids coincided with the strong radioactive peaks. Small amounts of radioactivities were detected in propionic acid peak and a peak assumed to be caproic acid. The rumen bacteria appeared to decompose much larger amounts of lysine than the rumen ciliate protozoa did. (auth.)

  13. Biodiversity of Bacteria Isolated from Different Soils

    Directory of Open Access Journals (Sweden)

    Fatma YAMAN

    2017-01-01

    Full Text Available The aim of this study was to determine the biodiversity of PHB producing bacteria isolated from soils where fruit and vegetable are cultivated (onion, grape, olive, mulberry and plum in Aydın providence. Morphological, cultural, biochemical, and molecular methods were used for bacteria identification. These isolated bacteria were identified by 16S rRNA sequencing and using BLAST. The following bacteria Bacillus thuringiensis (6, Bacillus cereus (8, Bacillus anthrachis (1, Bacillus circulans (1, Bacillus weihenstephanensis (1, Pseudomonas putida (1, Azotobacter chroococcum (1, Brevibacterium frigoritolerans (1, Burkholderia sp. (1, Staphylococcus epidermidis (1, Streptomyces exfoliatus (1, Variovorax paradoxus (1 were found. The Maximum Likelihood method was used to produce a molecular phylogenetic analysis and a phylogenetic tree was constructed. These bacteria can produce polyhydroxybutyrate (PHB which is an organic polymer with commercial potential as a biodegradable thermoplastic. PHB can be used instead of petrol derivated non-degradable plastics. For this reason, PHB producing microorganisms are substantial in industry.

  14. HYDROCARBON-DEGRADING BACTERIA AND SURFACTANT ACTIVITY

    Energy Technology Data Exchange (ETDEWEB)

    Brigmon, R; Topher Berry, T; Grazyna A. Plaza, G; jacek Wypych, j

    2006-08-15

    Fate of benzene ethylbenzene toluene xylenes (BTEX) compounds through biodegradation was investigated using two different bacteria, Ralstonia picketti (BP-20) and Alcaligenes piechaudii (CZOR L-1B). These bacteria were isolated from extremely polluted petroleum hydrocarbon contaminated soils. PCR and Fatty Acid Methyl Ester (FAME) were used to identify the isolates. Biodegradation was measured using each organism individually and in combination. Both bacteria were shown to degrade each of the BTEX compounds. Alcaligenes piechaudii biodegraded BTEXs more efficiently while mixed with BP-20 and individually. Biosurfactant production was observed by culture techniques. In addition 3-hydroxy fatty acids, important in biosurfactant production, was observed by FAME analysis. In the all experiments toluene and m+p- xylenes were better growth substrates for both bacteria than the other BTEX compounds. In addition, the test results indicate that the bacteria could contribute to bioremediation of aromatic hydrocarbons (BTEX) pollution increase biodegradation through the action by biosurfactants.

  15. Coryneform bacteria associated with canine otitis externa

    DEFF Research Database (Denmark)

    Aalbæk, Bent; Bemis, David A.; Schjærff, Mette

    2010-01-01

    This study aims to investigate the occurrence of coryneform bacteria in canine otitis externa. A combined case series and case-control study was carried out to improve the current knowledge on frequency and clinical significance of coryneform bacteria in samples from canine otitis externa. A total...... of 16 cases of otitis externa with involvement of coryneform bacteria were recorded at two referral veterinary hospitals in Denmark and the US, respectively. Coryneform bacteria were identified by partial 16S rRNA gene sequencing. Corynebacterium auriscanis was the most common coryneform species (10...... cases). Small colony variants of this species were also observed. Other coryneform isolates were identified as Corynebacterium amycolatum (3 cases), Corynebacterium freneyi (2 cases) and an Arcanobacterium-like species (1 case). The coryneform bacteria were in all cases isolated together with other...

  16. Hyphae colonizing bacteria associated with Penicillium bilaii

    DEFF Research Database (Denmark)

    Ghodsalavi, Behnoushsadat

    shown that mycorrhizal helper bacteria presenting in mycorrhizal fungi could stimulate fungal growth, promote establishment of root-fungus symbiosis and enhance plant production. But it is unknown if the comparable relationship exist between the non-mycorrhizal fungus P. bilaii and its hyphae associated...... bacteria. In the current PhD thesis, we assumed that hyphae-associated microbiome of P. bilaii might harbor helper bacteria with ability to improve fungal growth and P solubilization performance. Therefore, we aimed to isolate bacteria associated with the P. bilaii hyphae and identify the fungal growth...... stimulating bacteria with the perspective of promoting efficiency of Jumpstart in soil – plant system. For this purpose, most of the work within the current project was carried out by development of suitable model systems by mimicking the natural soil habitat to reach to the reliable performance in soil...

  17. Structural adaptations of octaheme nitrite reductases from haloalkaliphilic Thioalkalivibrio bacteria to alkaline pH and high salinity.

    Directory of Open Access Journals (Sweden)

    Anna Popinako

    Full Text Available Bacteria Tv. nitratireducens and Tv. paradoxus from soda lakes grow optimally in sodium carbonate/NaCl brines at pH range from 9.5 to 10 and salinity from 0.5 to 1.5 M Na+. Octaheme nitrite reductases (ONRs from haloalkaliphilic bacteria of genus Thioalkalivibrio are stable and active in a wide range of pH (up to 11 and salinity (up to 1 M NaCl. To establish adaptation mechanisms of ONRs from haloalkaliphilic bacteria a comparative analysis of amino acid sequences and structures of ONRs from haloalkaliphilic bacteria and their homologues from non-halophilic neutrophilic bacteria was performed. The following adaptation strategies were observed: (1 strategies specific for halophilic and alkaliphilic proteins (an increase in the number of aspartate and glutamate residues and a decrease in the number of lysine residues on the protein surface, (2 strategies specific for halophilic proteins (an increase in the arginine content and a decrease in the number of hydrophobic residues on the solvent-accessible protein surface, (3 strategies specific for alkaliphilic proteins (an increase in the area of intersubunit hydrophobic contacts. Unique adaptation mechanism inherent in the ONRs from bacteria of genus Thioalkalivibrio was revealed (an increase in the core in the number of tryptophan and phenylalanine residues, and an increase in the number of small side chain residues, such as alanine and valine, in the core.

  18. Surface-enhanced Raman scattering detection of bacteria on microarrays at single cell levels using silver nanoparticles

    International Nuclear Information System (INIS)

    Zhou, Haibo; Yang, Danting; Mircescu, Nicoleta E.; Ivleva, Natalia P.; Schwarzmeier, Kathrin; Niessner, Reinhard; Haisch, Christoph; Wieser, Andreas; Schubert, Sören

    2015-01-01

    We describe a method for the synthesis of SERS-active silver nanoparticles (AgNPs) directly on the surface of bacteria (bacteria-AgNPs), specifically of E. coli cells. This straightforward strategy allows for the sensitive determination of bacteria on a microarray platform. Antibodies were used as selective receptors on the microarray surface. The Raman signal of bacteria-AgNPs is about 10 times higher than that obtained previously with microarrays based on mixing bacteria and AgNPs (bacteria+AgNPs). The optimum SERS enhancement of bacteria-AgNPs is obtained under 633-nm laser excitation, and this most likely is due to the plasmonic interaction of aggregated AgNPs. The method allows for an identification and quantification even of single E. coli bacteria. In our perception, this straightforward approach represents a most valuable tool for the detection of E. coli and, conceivably, of other bacteria, and thus has a large potential in environmental monitoring, medical diagnosis, and in food safety and quality control. (author)

  19. Comparative cytotoxicity of periodontal bacteria

    International Nuclear Information System (INIS)

    Stevens, R.H.; Hammond, B.F.

    1988-01-01

    The direct cytotoxicity of sonic extracts (SE) from nine periodontal bacteria for human gingival fibroblasts (HGF) was compared. Equivalent dosages (in terms of protein concentration) of SE were used to challenge HGF cultures. The cytotoxic potential of each SE was assessed by its ability to (1) inhibit HGF proliferation, as measured by direct cell counts; (2) inhibit 3H-thymidine incorporation in HGF cultures; or (3) cause morphological alterations of the cells in challenged cultures. The highest concentration (500 micrograms SE protein/ml) of any of the SEs used to challenge the cells was found to be markedly inhibitory to the HGFs by all three of the criteria of cytotoxicity. At the lowest dosage tested (50 micrograms SE protein/ml); only SE from Actinobacillus actinomycetemcomitans, Bacteroides gingivalis, and Fusobacterium nucleatum caused a significant effect (greater than 90% inhibition or overt morphological abnormalities) in the HGFs as determined by any of the criteria employed. SE from Capnocytophaga sputigena, Eikenella corrodens, or Wolinella recta also inhibited cell proliferation and thymidine incorporation at this dosage; however, the degree of inhibition (5-50%) was consistently, clearly less than that of the first group of three organisms named above. The SE of the three other organisms tested (Actinomyces odontolyticus, Bacteroides intermedius, and Streptococcus sanguis) had little or no effect (0-10% inhibition) at this concentration. The data suggest that the outcome of the interaction between bacterial components and normal resident cells of the periodontium is, at least in part, a function of the bacterial species

  20. Tape Cassette Bacteria Detection System

    Science.gov (United States)

    1973-01-01

    The design, fabrication, and testing of an automatic bacteria detection system with a zero-g capability and based on the filter-capsule approach is described. This system is intended for monitoring the sterility of regenerated water in a spacecraft. The principle of detection is based on measuring the increase in chemiluminescence produced by the action of bacterial porphyrins (i.e., catalase, cytochromes, etc.) on a luminol-hydrogen peroxide mixture. Since viable as well as nonviable organisms initiate this luminescence, viable organisms are detected by comparing the signal of an incubated water sample with an unincubated control. Higher signals for the former indicate the presence of viable organisms. System features include disposable sealed sterile capsules, each containing a filter membrane, for processing discrete water samples and a tape transport for moving these capsules through a processing sequence which involves sample concentration, nutrient addition, incubation, a 4 Molar Urea wash and reaction with luminol-hydrogen peroxide in front of a photomultiplier tube. Liquids are introduced by means of a syringe needle which pierces a rubber septum contained in the wall of the capsule. Detection thresholds obtained with this unit towards E. coli and S. marcescens assuming a 400 ml water sample are indicated.

  1. Antioxidant Properties of Probiotic Bacteria

    Directory of Open Access Journals (Sweden)

    Yang Wang

    2017-05-01

    Full Text Available Oxidative stress defines a condition in which the prooxidant–antioxidant balance in the cell is disturbed, resulting in DNA hydroxylation, protein denaturation, lipid peroxidation, and apoptosis, ultimately compromising cells’ viability. Probiotics have been known for many beneficial health effects, and the consumption of probiotics alone or in food shows that strain-specific probiotics can present antioxidant activity and reduce damages caused by oxidation. However, the oxidation-resistant ability of probiotics, especially the underling mechanisms, is not properly understood. In this view, there is interest to figure out the antioxidant property of probiotics and summarize the mode of action of probiotic bacteria in antioxidation. Therefore, in the present paper, the antioxidant mechanisms of probiotics have been reviewed in terms of their ability to improve the antioxidant system and their ability to decrease radical generation. Since in recent years, oxidative stress has been associated with an altered gut microbiota, the effects of probiotics on intestinal flora composition are also elaborated.

  2. Metabolic engineering of lactic acid bacteria for the production of nutraceuticals

    NARCIS (Netherlands)

    Hugenholtz, J.; Sybesma, W.; Groot, M.N.; Wisselink, W.; Ladero, V.; Burgess, K.; Sinderen, van D.; Piard, J.C.; Eggink, G.; Smid, E.J.; Savoy, G.; Sesma, F.; Jansen, T.; Hols, P.; Kleerebezem, M.

    2002-01-01

    Lactic acid bacteria display a relatively simple and well-described metabolism where the sugar source is converted mainly to lactic acid. Here we will shortly describe metabolic engineering strategies on the level of sugar metabolism, that lead to either the efficient re-routing of the lactococcal

  3. Methods for baiting and enriching fungus-feeding (Mycophagous) rhizosphere bacteria

    NARCIS (Netherlands)

    Ballhausen, Max Bernhard; Veen, Van J.A.; Hundscheid, M.P.J.; Boer, De Wietse

    2015-01-01

    Mycophagous soil bacteria are able to obtain nutrients from living fungal hyphae. However, with exception of the soil bacterial genus Collimonas, occurrence of this feeding strategy has not been well examined. Evaluation of the importance of mycophagy in soil bacterial communities requires

  4. Oxalic acid: a signal molecule for fungus-feeding bacteria of the genus Collimonas?

    NARCIS (Netherlands)

    Rudnick, M.B.; van Veen, J. A.; De Boer, Wietse

    2015-01-01

    Mycophagous (=fungus feeding) soil bacteria of the genus Collimonas have been shown to colonize and grow on hyphae of different fungal hosts as the only source of energy and carbon. The ability to exploit fungal nutrient resources might require a strategy for collimonads to sense fungi in the soil

  5. European multicenter study on antimicrobial resistance in bacteria isolated from companion animal urinary tract infections

    DEFF Research Database (Denmark)

    Marques, Cátia; Gama, Luís Telo; Belas, Adriana

    2016-01-01

    for fluoroquinolone-resistant Proteus spp. isolated from companion animals from Belgium. CONCLUSIONS: This work brings new insights into the current status of antimicrobial resistance in bacteria isolated from companion animals with UTI in Europe and reinforces the need for strategies aiming to reduce resistance....

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

    DEFF Research Database (Denmark)

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

    2011-01-01

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

  7. Modeling the fate and transport of bacteria in agricultural and pasture lands using APEX

    Science.gov (United States)

    The Agricultural Policy/Environmental eXtender (APEX) model is a whole farm to small watershed scale continuous simulation model developed for evaluating various land management strategies. The current version, APEX0806, does not have the modeling capacity for fecal indicator bacteria fate and trans...

  8. 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.

  9. Appropriate strategies.

    Science.gov (United States)

    Halty, M

    1979-01-01

    Technology strategies are concerned with the production, distribution, and consumption of technology. Observation of less developed countries (LDCs) and international organizations shows that little attention is given to the development of a technology strategy. LDCs need to formulate a strategy of self-reliant technological development for the next decade. They should no longer be content to stand in a technologically dependent relationship to the developed countries. Such strategies must balance the ratio between investment in indigenous technologies and expenditure for foreign technology. The strategies change according to the level of industrialization achieved. The following considerations come into development of technology strategies: 1) determination of an appropriate balance among the accumulation, consumption, and distribution of technology; 2) the amount and level of government support; and 3) the balance between depth and breadth of technology to be encouraged.

  10. Environmental strategy

    DEFF Research Database (Denmark)

    Zabkar, Vesna; Cater, Tomaz; Bajde, Domen

    2013-01-01

    perspective, appropriate environmental strategies in compliance with environmental requirements aim at building competitive advantages through sustainable development. There is no universal “green” strategy that would be appropriate for each company, regardless of its market requirements and competitive......Environmental issues and the inclusion of environmental strategies in strategic thinking is an interesting subject of investigation. In general, managerial practices organized along ecologically sound principles contribute to a more environmentally sustainable global economy. From the managerial...

  11. Bacteria classification using Cyranose 320 electronic nose

    Directory of Open Access Journals (Sweden)

    Gardner Julian W

    2002-10-01

    Full Text Available Abstract Background An electronic nose (e-nose, the Cyrano Sciences' Cyranose 320, comprising an array of thirty-two polymer carbon black composite sensors has been used to identify six species of bacteria responsible for eye infections when present at a range of concentrations in saline solutions. Readings were taken from the headspace of the samples by manually introducing the portable e-nose system into a sterile glass containing a fixed volume of bacteria in suspension. Gathered data were a very complex mixture of different chemical compounds. Method Linear Principal Component Analysis (PCA method was able to classify four classes of bacteria out of six classes though in reality other two classes were not better evident from PCA analysis and we got 74% classification accuracy from PCA. An innovative data clustering approach was investigated for these bacteria data by combining the 3-dimensional scatter plot, Fuzzy C Means (FCM and Self Organizing Map (SOM network. Using these three data clustering algorithms simultaneously better 'classification' of six eye bacteria classes were represented. Then three supervised classifiers, namely Multi Layer Perceptron (MLP, Probabilistic Neural network (PNN and Radial basis function network (RBF, were used to classify the six bacteria classes. Results A [6 × 1] SOM network gave 96% accuracy for bacteria classification which was best accuracy. A comparative evaluation of the classifiers was conducted for this application. The best results suggest that we are able to predict six classes of bacteria with up to 98% accuracy with the application of the RBF network. Conclusion This type of bacteria data analysis and feature extraction is very difficult. But we can conclude that this combined use of three nonlinear methods can solve the feature extraction problem with very complex data and enhance the performance of Cyranose 320.

  12. Folate Production by Probiotic Bacteria

    Directory of Open Access Journals (Sweden)

    Stefano Raimondi

    2011-01-01

    Full Text Available Probiotic bacteria, mostly belonging to the genera Lactobacillus and Bifidobacterium, confer a number of health benefits to the host, including vitamin production. With the aim to produce folate-enriched fermented products and/or develop probiotic supplements that accomplish folate biosynthesis in vivo within the colon, bifidobacteria and lactobacilli have been extensively studied for their capability to produce this vitamin. On the basis of physiological studies and genome analysis, wild-type lactobacilli cannot synthesize folate, generally require it for growth, and provide a negative contribution to folate levels in fermented dairy products. Lactobacillus plantarum constitutes an exception among lactobacilli, since it is capable of folate production in presence of para-aminobenzoic acid (pABA and deserves to be used in animal trials to validate its ability to produce the vitamin in vivo. On the other hand, several folate-producing strains have been selected within the genus Bifidobacterium, with a great variability in the extent of vitamin released in the medium. Most of them belong to the species B. adolescentis and B. pseudocatenulatum, but few folate producing strains are found in the other species as well. Rats fed a probiotic formulation of folate-producing bifidobacteria exhibited increased plasma folate level, confirming that the vitamin is produced in vivo and absorbed. In a human trial, the same supplement raised folate concentration in feces. The use of folate-producing probiotic strains can be regarded as a new perspective in the specific use of probiotics. They could more efficiently confer protection against inflammation and cancer, both exerting the beneficial effects of probiotics and preventing the folate deficiency that is associated with premalignant changes in the colonic epithelia.

  13. Magnetotactic Bacteria from Extreme Environments

    Directory of Open Access Journals (Sweden)

    Christopher T. Lefèvre

    2013-03-01

    Full Text Available Magnetotactic bacteria (MTB represent a diverse collection of motile prokaryotes that biomineralize intracellular, membrane-bounded, tens-of-nanometer-sized crystals of a magnetic mineral called magnetosomes. Magnetosome minerals consist of either magnetite (Fe3O4 or greigite (Fe3S4 and cause cells to align along the Earth’s geomagnetic field lines as they swim, a trait called magnetotaxis. MTB are known to mainly inhabit the oxic–anoxic interface (OAI in water columns or sediments of aquatic habitats and it is currently thought that magnetosomes function as a means of making chemotaxis more efficient in locating and maintaining an optimal position for growth and survival at the OAI. Known cultured and uncultured MTB are phylogenetically associated with the Alpha-, Gamma- and Deltaproteobacteria classes of the phylum Proteobacteria, the Nitrospirae phylum and the candidate division OP3, part of the Planctomycetes-Verrucomicrobia-Chlamydiae (PVC bacterial superphylum. MTB are generally thought to be ubiquitous in aquatic environments as they are cosmopolitan in distribution and have been found in every continent although for years MTB were thought to be restricted to habitats with pH values near neutral and at ambient temperature. Recently, however, moderate thermophilic and alkaliphilic MTB have been described including: an uncultured, moderately thermophilic magnetotactic bacterium present in hot springs in northern Nevada with a probable upper growth limit of about 63 °C; and several strains of obligately alkaliphilic MTB isolated in pure culture from different aquatic habitats in California, including the hypersaline, extremely alkaline Mono Lake, with an optimal growth pH of >9.0.

  14. Fermentative Bacteria Influence the Competition between Denitrifiers and DNRA Bacteria

    Directory of Open Access Journals (Sweden)

    Eveline M. van den Berg

    2017-09-01

    results of this study clearly show that not only the ratio of available substrates, but also the nature of the electron donor influences the outcome of competition between DNRA and denitrification. Apparently, fermentative bacteria are competitive for the electron donor and thereby alter the ratio of available substrates for nitrate reduction.

  15. The Microworld of Marine-Bacteria

    DEFF Research Database (Denmark)

    JØRGENSEN, BB

    1995-01-01

    Microsensor studies show that the marine environment in the size scale of bacteria is physically and chemically very different from the macroenvironment. The microbial world of the sediment-water interface is thus dominated by water viscosity and steep diffusion gradients. Because of the diverse...... metabolism types, bacteria in the mostly anoxic sea floor play an important role in the major element cycles of the ocean. The communities of giant, filamentous sulfur bacteria that live in the deep-sea hydrothermal vents or along the Pacific coast of South America are presented here as examples....

  16. Labelling of bacteria with indium chelates

    International Nuclear Information System (INIS)

    Kleinert, P.; Pfister, W.; Endert, G.; Sproessig, M.

    1985-01-01

    The indium chelates were prepared by reaction of radioactive indiumchloride with 10 μg oxine, 15 μg tropolone and 3 mg acetylacetone, resp. The formed chelates have been incubated with 10 9 germs/ml for 5 minutes, with labelling outputs from 90 to 95%. Both gram-positive (Streptococcus, Staphylococcus) and gram-negative bacteria (Escherichia coli) can be labelled. The reproductive capacity of the bacteria was not impaired. The application of indium labelled bacteria allows to show the distribution of microorganisms within the living organism and to investigate problems of bacterial adherence. (author)

  17. Mortality of fecal bacteria in seawater

    International Nuclear Information System (INIS)

    Garcia-Lara, J.; Menon, P.; Servais, P.; Billen, G.

    1991-01-01

    The authors propose a method for determining the mortality rate for allochthonous bacteria released in aquatic environments without interference due to the loss of culturability in specific culture media. This method consists of following the disappearance of radioactivity from the trichloracetic acid-insoluble fraction in water samples to which [ 3 H]thymidine-prelabeled allochthonous bacteria have been added. In coastal seawater, they found that the actual rate of disappearance of fecal bacteria was 1 order of magnitude lower than the rate of loss of culturability on specific media. Minor adaptation of the procedure may facilitate assessment of the effect of protozoan grazing and bacteriophage lysis on the overall bacterial mortality rate

  18. Pu sorption to activated conglomerate anaerobic bacteria

    International Nuclear Information System (INIS)

    Sasaki, Takayuki; Kudo, Akira

    2001-01-01

    The sorption of Pu to the anaerobic bacteria activated under specific conditions of temperature, pH and depleted nutrients after long dormant period was investigated. After 4 h at neutral pH, the distribution coefficient (K d ) between bacteria and aqueous phase at 308 and 278 K had around 10 3 to 10 4 . After over 5 days, however, the K d at only 308 K had increased to over 10 5 . Sterilized (dead) and dormant anaerobic bacteria adsorbed Pu to the same extent. (author)

  19. Bacteria Culture Test: MedlinePlus Lab Test Information

    Science.gov (United States)

    ... this page: https://medlineplus.gov/labtests/bacteriaculturetest.html Bacteria Culture Test To use the sharing features on this page, please enable JavaScript. What is a Bacteria Culture Test? Bacteria are a large group of ...

  20. Evaluation Strategy

    DEFF Research Database (Denmark)

    Coto Chotto, Mayela; Wentzer, Helle; Dirckinck-Holmfeld, Lone

    2009-01-01

    The paper presents an evaluation strategy based on deliberate ideals and principles of dialogue design. The evaluation strategy is based on experiential phenomenology taking the point of departure for design and evaluation processes in the experienced practitioners themselves. The article present...... the evaluation strategy and methodology of a research project Making Online Path to Enter new Markets, MOPEM. It is an EU-research project with partners from different Educational Institutions of Technology and Business in five European Countries.......The paper presents an evaluation strategy based on deliberate ideals and principles of dialogue design. The evaluation strategy is based on experiential phenomenology taking the point of departure for design and evaluation processes in the experienced practitioners themselves. The article presents...

  1. Phaeobacter inhibens as probiotic bacteria in non-axenic Artemia and algae cultures

    OpenAIRE

    Grotkjær, T.; Bentzon-Tilia, M.; D'Alvise, P.; Dierckens, K.; Bossier, P.; Gram, L.

    2016-01-01

    The growing aquaculture industry is in need for non-antibiotic based disease control strategies to reduce risk of bacteria developing and spreading antibiotic resistance. We have previously, in axenic model systems of live larval feed, demonstrated that bacteria from the Roseobacter clade can antagonize fish pathogens such as Vibrio anguillarum and Vibrio harveyi and that they can reduce larval mortality in challenge trials. However, in the aquaculture production, a natural microbiota is pres...

  2. Contribution of midgut bacteria to blood digestion and egg production in aedes aegypti (diptera: culicidae (L.

    Directory of Open Access Journals (Sweden)

    Pimenta Paulo FP

    2011-06-01

    Full Text Available Abstract Background The insect gut harbors a variety of microorganisms that probably exceed the number of cells in insects themselves. These microorganisms can live and multiply in the insect, contributing to digestion, nutrition, and development of their host. Recent studies have shown that midgut bacteria appear to strengthen the mosquito's immune system and indirectly enhance protection from invading pathogens. Nevertheless, the physiological significance of these bacteria for mosquitoes has not been established to date. In this study, oral administration of antibiotics was employed in order to examine the contribution of gut bacteria to blood digestion and fecundity in Aedes aegypti. Results The antibiotics carbenicillin, tetracycline, spectinomycin, gentamycin and kanamycin, were individually offered to female mosquitoes. Treatment of female mosquitoes with antibiotics affected the lysis of red blood cells (RBCs, retarded the digestion of blood proteins and reduced egg production. In addition, antibiotics did not affect the survival of mosquitoes. Mosquito fertility was restored in the second gonotrophic cycle after suspension of the antibiotic treatment, showing that the negative effects of antibiotics in blood digestion and egg production in the first gonotrophic cycle were reversible. Conclusions The reduction of bacteria affected RBC lysis, subsequently retarded protein digestion, deprived mosquito from essential nutrients and, finally, oocyte maturation was affected, resulting in the production of fewer viable eggs. These results indicate that Ae. aegypti and its midgut bacteria work in synergism to digest a blood meal. Our findings open new possibilities to investigate Ae. aegypti-associated bacteria as targets for mosquito control strategies.

  3. Enteropathogenic Escherichia coli, Samonella, Shigella and Yersinia: cellular aspects of host-bacteria interactions in enteric diseases

    Directory of Open Access Journals (Sweden)

    Reis Roberta

    2010-07-01

    Full Text Available Abstract A successful infection of the human intestine by enteropathogenic bacteria depends on the ability of bacteria to attach and colonize the intestinal epithelium and, in some cases, to invade the host cell, survive intracellularly and disseminate from cell to cell. To accomplish these processes bacteria have evolved an arsenal of molecules that are mostly secreted by dedicated type III secretion systems, and that interact with the host, subverting normal cellular functions. Here we overview the most important molecular strategies developed by enteropathogenic Escherichia coli, Salmonella enterica, Shigella flexneri, and Yersinia enterocolitica to cause enteric infections. Despite having evolved different effectors, these four microorganisms share common host cellular targets.

  4. Flow cytometry, fluorescent probes, and flashing bacteria

    NARCIS (Netherlands)

    Bunthof, C.J.

    2002-01-01


    Key words: fluorescent probes, flow cytometry, CSLM, viability, survival, microbial physiology, lactic acid bacteria, Lactococcus lactis , Lactobacillus plantarum , cheese, milk,

  5. Effect of leukocyte hydrolases on bacteria

    International Nuclear Information System (INIS)

    Cohen, D.; Michel, J.; Ferne, M.; Bergner-Rabinowitz, S.; Ginsburg, I.

    1979-01-01

    Leukocyte extracts, trypsin, and lysozyme are all capable of releasing the bulk of the LPS from S. typhi, S. typhimurium, and E. coli. Bacteria which have been killed by heat, ultraviolet irradiation, or by a variety of metabolic inhibitors and antibiotics which affect protein, DNA, RNA, and cell wall synthesis no longer yield soluble LPS following treatment with the releasing agents. On the other hand, bacteria which are resistant to certain of the antibiotics yield nearly the full amount of soluble LPS following treatment, suggesting that certain heatabile endogenous metabolic pathways collaborate with the releasing agents in the release of LPS from the bacteria. It is suggested that some of the beneficial effects of antibiotics on infections with gram-negative bacteria may be the prevention of massive release of endotoxin by leukocyte enzymes in inflammatory sites

  6. Systemic resistance induced by rhizosphere bacteria

    NARCIS (Netherlands)

    Loon, L.C. van; Bakker, P.A.H.M.; Pieterse, C.M.J.

    1998-01-01

    Nonpathogenic rhizobacteria can induce a systemic resistance in plants that is phenotypically similar to pathogen-induced systemic acquired resistance (SAR). Rhizobacteria-mediated induced systemic resistance (ISR) has been demonstrated against fungi, bacteria, and viruses in Arabidopsis, bean,

  7. Lactic acid bacteria: microbiological and functional aspects

    National Research Council Canada - National Science Library

    Lahtinen, Sampo

    2012-01-01

    "Updated with the substantial progress made in lactic acid and bacteria research since the third edition, this fourth volume discusses improved insights in genetics and new molecular biological techniques...

  8. Comparative genomics of the lactic acid bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Makarova, K.; Slesarev, A.; Wolf, Y.; Sorokin, A.; Mirkin, B.; Koonin, E.; Pavlov, A.; Pavlova, N.; Karamychev, V.; Polouchine, N.; Shakhova, V.; Grigoriev, I.; Lou, Y.; Rokhsar, D.; Lucas, S.; Huang, K.; Goodstein, D. M.; Hawkins, T.; Plengvidhya, V.; Welker, D.; Hughes, J.; Goh, Y.; Benson, A.; Baldwin, K.; Lee, J. -H.; Diaz-Muniz, I.; Dosti, B.; Smeianov, V; Wechter, W.; Barabote, R.; Lorca, G.; Altermann, E.; Barrangou, R.; Ganesan, B.; Xie, Y.; Rawsthorne, H.; Tamir, D.; Parker, C.; Breidt, F.; Broadbent, J.; Hutkins, R.; O' Sullivan, D.; Steele, J.; Unlu, G.; Saier, M.; Klaenhammer, T.; Richardson, P.; Kozyavkin, S.; Weimer, B.; Mills, D.

    2006-06-01

    Lactic acid-producing bacteria are associated with various plant and animal niches and play a key role in the production of fermented foods and beverages. We report nine genome sequences representing the phylogenetic and functional diversity of these bacteria. The small genomes of lactic acid bacteria encode a broad repertoire of transporters for efficient carbon and nitrogen acquisition from the nutritionally rich environments they inhabit and reflect a limited range of biosynthetic capabilities that indicate both prototrophic and auxotrophic strains. Phylogenetic analyses, comparison of gene content across the group, and reconstruction of ancestral gene sets indicate a combination of extensive gene loss and key gene acquisitions via horizontal gene transfer during the coevolution of lactic acid bacteria with their habitats.

  9. Do bacteria, not fish, produce 'fish kairomone'?

    NARCIS (Netherlands)

    Ringelberg, J.; Van Gool, E.

    1998-01-01

    Fish-associated chemicals enhance phototactic downward swimming in Daphnia. If perch were treated with the antibiotic ampicillin, this enhancement was significantly decreased. Therefore, not fish, but bacteria associated with fish, seem to produce this kairomone. [KEYWORDS: Diel vertical migration;

  10. Bacteria-mediated bisphenol A degradation.

    Science.gov (United States)

    Zhang, Weiwei; Yin, Kun; Chen, Lingxin

    2013-07-01

    Bisphenol A (BPA) is an important monomer in the manufacture of polycarbonate plastics, food cans, and other daily used chemicals. Daily and worldwide usage of BPA and BPA-contained products led to its ubiquitous distribution in water, sediment/soil, and atmosphere. Moreover, BPA has been identified as an environmental endocrine disruptor for its estrogenic and genotoxic activity. Thus, BPA contamination in the environment is an increasingly worldwide concern, and methods to efficiently remove BPA from the environment are urgently recommended. Although many factors affect the fate of BPA in the environment, BPA degradation is mainly depended on the metabolism of bacteria. Many BPA-degrading bacteria have been identified from water, sediment/soil, and wastewater treatment plants. Metabolic pathways of BPA degradation in specific bacterial strains were proposed, based on the metabolic intermediates detected during the degradation process. In this review, the BPA-degrading bacteria were summarized, and the (proposed) BPA degradation pathway mediated by bacteria were referred.

  11. Abundance, viability and culturability of Antarctic bacteria

    Digital Repository Service at National Institute of Oceanography (India)

    LokaBharathi, P.A.; DeSouza, M.J.B.D.; Nair, S.; Chandramohan, D.

    The viability of total number of bacteria decide the mineralisation rate in any ecosystem and ultimately the fertility of the region. This study aims at establishing the extent of viability in the standing stock of the Antarctic bacterial population...

  12. Interactions between phototrophic bacteria in marine sediments

    NARCIS (Netherlands)

    de Wit, Rutger

    1989-01-01

    Phototrophic bacteria are the most consicious organisms occuring in laminated microbial sediment ecosystems (microbial mats). In the Waddensea area ecosystems consisting of a toplayer of the cyanobacterium Microleus chthonoplastes overlying a red layer of the purple sulfur bacterium Thiocapsa

  13. Molecular genetic studies on obligate anaerobic bacteria

    International Nuclear Information System (INIS)

    Woods, D.R.

    1982-01-01

    Molecular genetic studies on obligate anaerobic bacteria have lagged behind similar studies in aerobes. However, the current interest in biotechnology, the involvement of anaerobes in disease and the emergence of antibioticresistant strains have focused attention on the genetics of anaerobes. This article reviews molecular genetic studies in Bacteroides spp., Clostridium spp. and methanogens. Certain genetic systems in some anaerobes differ from those in aerobes and illustrate the genetic diversity among bacteria

  14. Ecology: Electrical Cable Bacteria Save Marine Life

    DEFF Research Database (Denmark)

    Nielsen, Lars Peter

    2016-01-01

    Animals at the bottom of the sea survive oxygen depletion surprisingly often, and a new study identifies cable bacteria in the sediment as the saviors. The bacterial electrical activity creates an iron 'carpet', trapping toxic hydrogen sulfide.......Animals at the bottom of the sea survive oxygen depletion surprisingly often, and a new study identifies cable bacteria in the sediment as the saviors. The bacterial electrical activity creates an iron 'carpet', trapping toxic hydrogen sulfide....

  15. Extracellular deoxyribonuclease production by periodontal bacteria.

    Science.gov (United States)

    Palmer, L J; Chapple, I L C; Wright, H J; Roberts, A; Cooper, P R

    2012-08-01

    Whilst certain bacteria have long been known to secrete extracellular deoxyribonuclease (DNase), the purpose in microbial physiology was unclear. Recently, however, this enzyme has been demonstrated to confer enhanced virulence, enabling bacteria to evade the host's immune defence of extruded DNA/chromatin filaments, termed neutrophil extracellular traps (NETs). As NETs have recently been identified in infected periodontal tissue, the aim of this study was to screen periodontal bacteria for extracellular DNase activity. To determine whether DNase activity was membrane bound or secreted, 34 periodontal bacteria were cultured in broth and on agar plates. Pelleted bacteria and supernatants from broth cultures were analysed for their ability to degrade DNA, with relative activity levels determined using an agarose gel electrophoresis assay. Following culture on DNA-supplemented agar, expression was determined by the presence of a zone of hydrolysis and DNase activity related to colony size. Twenty-seven bacteria, including red and orange complex members Porphyromonas gingivalis, Tannerella forsythia, Fusobacterium nucleatum, Parvimonas micra, Prevotella intermedia, Streptococcus constellatus, Campylobacter rectus and Prevotella nigrescens, were observed to express extracellular DNase activity. Differences in DNase activity were noted, however, when bacteria were assayed in different culture states. Analysis of the activity of secreted DNase from bacterial broth cultures confirmed their ability to degrade NETs. The present study demonstrates, for the first time, that DNase activity is a relatively common property of bacteria associated with advanced periodontal disease. Further work is required to determine the importance of this bacterial DNase activity in the pathogenesis of periodontitis. © 2011 John Wiley & Sons A/S.

  16. Occurrence of diazotrophic bacteria in Araucaria angustifolia

    OpenAIRE

    Neroni,Rafaela de Fátima; Cardoso,Elke Jurandy Bran Nogueira

    2007-01-01

    Araucaria angustifolia is an environmentally threatened tree and the whole biota of the Araucaria Forest should be investigated with the aim of its preservation. Diazotrophic bacteria are extremely important for the maintenance of ecosystems, but they have never been studied in Araucaria Forests. In this study, diazotrophic bacteria were isolated from Araucaria roots and soil, when grown in semi-specific, semi-solid media. The diazotrophic character of some recovered isolates could be confirm...

  17. [Teichoic acids from lactic acid bacteria].

    Science.gov (United States)

    Livins'ka, O P; Harmasheva, I L; Kovalenko, N K

    2012-01-01

    The current view of the structural diversity of teichoic acids and their involvement in the biological activity of lactobacilli has been reviewed. The mechanisms of effects of probiotic lactic acid bacteria, in particular adhesive and immunostimulating functions have been described. The prospects of the use of structure data of teichoic acid in the assessment of intraspecific diversity of lactic acid bacteria have been also reflected.

  18. A nanovehicle developed for treating deep-seated bacteria using low-dose X-ray.

    Science.gov (United States)

    Pan, Chien-Lin; Chen, Ming-Hong; Tung, Fu-I; Liu, Tse-Ying

    2017-01-01

    Many non-antibiotic strategies, such as photocatalysis and photodynamic therapy, have been proposed to inhibit and/or kill bacteria. However, these approaches still have drawbacks such as insufficient bacterial specificity and the limited penetration depth of ultraviolet and near-infrared light. To overcome these limitations, we developed a bacteria-specific anti-bacterial technique via using low-dose X-ray. Graphene oxide quantum dots (GQDs, a multifunctional vehicle) conjugated with vancomycin (Van, a bacteria-targeting ligand) were assembled with Protoporphyrin IX (PpIX, a photo/radiation sensitizer) to yield a novel Van-GQDs/PpIX complex that specifically attached to Escherichia coli and efficiently generated intracellular reactive oxygen species following X-ray activation. Delivery using GQDs increased the PpIX/Van ratio in the target bacterial cell, damaged bacterial cell wall, and enhanced X-ray-induced PpIX activation. Hence, this approach allowed for the use of a low-dose X-ray to efficiently activate the Van-GQDs/PpIX complex to exert its bactericidal effects on Escherichia coli without damaging normal cells. Furthermore, the E. coli did not develop resistance to the proposed approach for at least 7 rounds of repeated administration during one week. Thus, this proposed vehicle exhibiting bacteria-specific X-ray-triggered toxicity is a promising alternative to antibiotics for treating serious bacterial infections occurring in deep-seated tissues/organs (e.g., osteomyelitis and peritonitis). Administration of antibiotics is the most common treatment modality for bacterial infections. However, in some cases, patient attributes such as age, health, tolerance to antibiotics do not allow for the use of high-dose antibiotics. In addition, some bacteria develop resistance to antibiotics because of improper and long-term use of these agents. Therefore, non-antibiotic strategies to treat deeply situated bacterial infections, such as osteomyelitis, are urgently

  19. Mimicking Seawater For Culturing Marine Bacteria

    DEFF Research Database (Denmark)

    Rygaard, Anita Mac; Sonnenschein, Eva; Gram, Lone

    2015-01-01

    Only about 1% of marine bacteria have been brought into culture using traditional techniques. The purpose of this study was to investigate if mimicking the natural bacterial environment can increase culturability.We used marine substrates containing defined algal polymers or gellan gum as solidif......Only about 1% of marine bacteria have been brought into culture using traditional techniques. The purpose of this study was to investigate if mimicking the natural bacterial environment can increase culturability.We used marine substrates containing defined algal polymers or gellan gum...... as solidifying agents, and enumerated bacteria from seawater and algal exudates. We tested if culturability could be influenced by addition of quorum sensing signals (AHLs). All plates were incubated at 15°C. Bacterial counts (CFU/g) from algal exudates from brown algae were highest on media containing algal...... polymers. In general, bacteria isolated from algal exudates preferred more rich media than bacteria isolated from seawater. Overall, culturability ranged from 0.01 to 0.8% as compared to total cell count. Substitution of agar with gellan gum increased the culturability of seawater bacteria approximately...

  20. Antibiotic-resistant bacteria in drinking water.

    Science.gov (United States)

    Armstrong, J L; Shigeno, D S; Calomiris, J J; Seidler, R J

    1981-08-01

    We analyzed drinking water from seven communities for multiply antibiotic-resistant (MAR) bacteria (bacteria resistant to two or more antibiotics) and screened the MAR bacterial isolates obtained against five antibiotics by replica plating. Overall, 33.9% of 2,653 standard plate count bacteria from treated drinking waters were MAR. Two different raw water supplies for two communities carried MAR standard plate count bacteria at frequencies of 20.4 and 18.6%, whereas 36.7 and 67.8% of the standard plate count populations from sites within the respective distribution systems were MAR. Isolate identification revealed that MAR gram-positive cocci (Staphylococcus) and MAR gram-negative, nonfermentative rods (Pseudomonas, Alcaligenes, Moraxella-like group M, and Acinetobacter) were more common in drinking waters than in untreated source waters. Site-to-site variations in generic types and differences in the incidences of MAR organisms indicated that shedding of MAR bacteria living in pipelines may have contributed to the MAR populations in tap water. We conclude that the treatment of raw water and its subsequent distribution select for standard plate count bacteria exhibiting the MAR phenotype.

  1. Safety strategy

    International Nuclear Information System (INIS)

    Schultheiss, G.F.

    1980-01-01

    The basis for safety strategy in nuclear industry and especially nuclear power plants is the prevention of radioactivity release inside or outside of the technical installation. Therefore either technical or administrative measures are combined to a general strategy concept. This introduction will explain in more detail the following topics: - basic principles of safety - lines of assurance (LOA) - defense in depth - deterministic and probabilistic methods. This presentation is seen as an introduction to the more detailed discussion following in this course, nevertheless some selected examples will be used to illustrate the aspects of safety strategy development although they might be repeated later on. (orig.)

  2. Export strategy

    DEFF Research Database (Denmark)

    Knudsen, Thorbjørn; Koed Madsen, Tage

    2002-01-01

    It is argued here that traditional export strategy research (encompassing the study of internationalization processes and export performance) is characterized by weak theoretical foundations and could benefit from a reorientation towards a dynamic capabilities perspective (DCP). We seek to draw...... on insights from DCP in order to devise a theoretical basis that could enrich export strategy research. Although our development of DCP insights builds on previous work, it also adds a crucial distinction between knowledge stocks and informational architecture. Changes in architecture are of greater...... importance. Following this elaboration of the dynamic capabilities perspective, we outline some implications and guidelines for future export strategy research....

  3. Vapor-induced transfer of bacteria in the absence of mechanical disturbances

    International Nuclear Information System (INIS)

    Ayoub, G.M.; Dahdah, L.; Alameddine, I.; Malaeb, L.

    2014-01-01

    Graphical abstract: - Highlights: • Study is first to investigate the possibility of transfer of bacteria through vapor. • Bacteria exhibited transfer in the absence of mechanical disturbances in reactors. • Gram positive smaller bacteria transferred more than gram negative larger bacteria. • Transfer probability increases at optimal growth temperature of mesophilic bacteria. • Salinity lowers bacterial survival and has synergistic effect with temperature. - Abstract: Transfer of bacteria through water vapor generated at moderate temperatures (30–50 °C) in passive solar stills, has scarcely been reported. The objective of this research was to investigate whether bacteria in highly humid atmospheres can get transferred through water vapor in the absence of other transfer media to find their way to the distillate. To achieve this objective, passive solar reactors were chosen as the medium for experimentation, and distillation experiments were conducted by spiking a pure bacterial culture (Escherichia coli, Klebsiella pneumonia or Enterococcus faecalis) in low mineralized water vs. highly mineralized water in the dark under moderate temperatures ranges (30–35 °C, 40–45 °C and 50–55 °C). Results showed that bacteria indeed get transferred with the vapor in stills when not exposed to solar U.V. radiation. The trends observed were adequately explained by a zero-modified Hurdle–Poisson model. The numbers of cultivable bacterial colonies transferred were bacterial size, water type and temperature dependent with highest transfers occurring in E. faecalis > E. coli > K. pneumonia at the 40 °C range in low mineralized water. Proper management strategies are recommended to achieve complete disinfection in solar stills

  4. Development of Electrochemical Biosensors for Ultrasensitive Detection of Bacteria in the Environment

    DEFF Research Database (Denmark)

    Fapyane, Deby

    2018-01-01

    to those conventional methods, are intensively studied. Biosensor technology is one of the strategies for rapid monitoring of pathogens such as bacteria, virus, and parasites in the environment. Among them, the electrochemical biosensor offers simple, rapid, cost-effective and possibility...... for ultrasensitive detection of bacterial cells, DNA and rRNA. Several key operational parameters were assessed such as the optimization of probe design and labeling molecules. Here, more specifically we used two novel labels for the development of the electrochemical biosensor for bacteria detection; cellulase...

  5. Nanotextile membranes for bacteria Escherichia coli capturing

    Directory of Open Access Journals (Sweden)

    Jaroslav Lev

    2010-01-01

    Full Text Available The article describes an experimental study dealing with the possibility of nanotextile materials usa­ge for microbiologically contaminated water filtration. The aim of the study is to verify filtration ability of different nanotextile materials and evaluate the possibilities of practical usage. Good detention ability of these materials in the air filtration is the presumption for nanotextile to be used for bacteria filtration from a liquid. High nanotextile porosity with the nanotextile pores dimensions smaller than a bacteria size predicates the possibility of a successful usage of these materials. For the experiment were used materials made from electrospinning nanofibres under the label PA612, PUR1, PUR2 s PUR3 on the supporting unwoven textiles (viscose and PP. As a model simulation of the microbial contamination, bacteria Escherichia coli was chosen. Contaminated water was filtered during the overpressure activity of 105Pa on the input side of the filter from the mentioned material. After three-day incubation on the nutrient medium, cultures found in the samples before and after filtration were compared. In the filtrated water, bacteria E. coli were indicated, which did not verify the theoretical presumptions about an absolut bacteria detention. However, used materials caught at least 94% of bacteria in case of material PUR1 and up to 99,996% in case of material PUR2. These results predict the possibility of producing effective nanotextile filters for microbiologically contaminated water filtration.Recommendation: For the production of materials with better filtrating qualities, experiments need to be done, enabling better understanding of the bacteria detention mechanisms on the nanotextile material, and parameters of the used materials that influence the filtrating abilities need to be verified.

  6. [Spectrum and susceptibility of preoperative conjunctival bacteria].

    Science.gov (United States)

    Fernández-Rubio, M E; Cuesta-Rodríguez, T; Urcelay-Segura, J L; Cortés-Valdés, C

    2013-12-01

    To describe the conjunctival bacterial spectrum of our patients undergoing intraocular surgery and their antibiotic sensitivity during the study period. A retrospective study of preoperative conjunctival culture of patients consecutively scheduled for intraocular surgery from 21 February 2011 to 1 April 2013. Specimens were directly seeded onto blood-agar and MacConkey-agar (aerobiosis incubation, 2 days), and on chocolate-agar (6% CO2 incubation, 7 days). The identified bacteria were divided into 3 groups according to their origin; the bacteria susceptibility tests were performed on those more pathogenic and on some of the less pathogenic when more than 5 colonies were isolated. The sensitivity of the exigent growing bacteria was obtained with disk diffusion technique, and for of the non-exigent bacteria by determining their minimum inhibitory concentration. The Epidat 3.1 program was used for statistical calculations. A total of 13,203 bacteria were identified in 6,051 cultures, with 88.7% being typical colonizers of conjunctiva (group 1), 8.8% typical of airways (group 2), and the remaining 2.5% of undetermined origin (group 3). 530 cultures (8.8%) were sterile. The sensitivity of group 1 was: 99% vancomycin, 95% rifampicin, 87% chloramphenicol, 76% tetracycline. Levels of co-trimoxazole, aminoglycosides, quinolones, β-lactams and macrolides decreased since 2007. The group 2 was very sensitive to chloramphenicol, cefuroxime, rifampicin, ciprofloxacin and amoxicillin/clavulanate. In group 3, to levofloxacin 93%, ciprofloxacin 89%, tobramycin 76%, but ceftazidime 53% and cefuroxime 29% decreased. None of the tested antibiotics could eradicate all possible conjunctival bacteria. Bacteria living permanently on the conjunctiva (group 1) have achieved higher resistance than the eventual colonizers. Copyright © 2013 Sociedad Española de Oftalmología. Published by Elsevier Espana. All rights reserved.

  7. Magnetosome chain superstructure in uncultured magnetotactic bacteria

    International Nuclear Information System (INIS)

    Abraçado, Leida G; Farina, Marcos; Abreu, Fernanda; Keim, Carolina N; Lins, Ulysses; Campos, Andrea P C

    2010-01-01

    Magnetotactic bacteria produce magnetosomes, which are magnetic particles enveloped by biological membranes, in a highly controlled mineralization process. Magnetosomes are used to navigate in magnetic fields by a phenomenon called magnetotaxis. Two levels of organization and control are recognized in magnetosomes. First, magnetotactic bacteria create a spatially distinct environment within vesicles defined by their membranes. In the vesicles, the bacteria control the size, composition and purity of the mineral content of the magnetic particles. Unique crystal morphologies are produced in magnetosomes as a consequence of this bacterial control. Second, magnetotactic bacteria organize the magnetosomes in chains within the cell body. It has been shown in a particular case that the chains are positioned within the cell body in specific locations defined by filamentous cytoskeleton elements. Here, we describe an additional level of organization of the magnetosome chains in uncultured magnetotactic cocci found in marine and freshwater sediments. Electron microscopy analysis of the magnetosome chains using a goniometer showed that the magnetic crystals in both types of bacteria are not oriented at random along the crystal chain. Instead, the magnetosomes have specific orientations relative to the other magnetosomes in the chain. Each crystal is rotated either 60°, 180° or 300° relative to their neighbors along the chain axis, causing the overlapping of the (1 1 1) and (1-bar 1-bar 1-bar) capping faces of neighboring crystals. We suggest that genetic determinants that are not present or active in bacteria with magnetosomes randomly rotated within a chain must be present in bacteria that organize magnetosomes so precisely. This particular organization may also be used as an indicative biosignature of magnetosomes in the study of magnetofossils in the cases where this symmetry is observed

  8. Chemically enhanced sunlight for killing bacteria

    International Nuclear Information System (INIS)

    Block, S.S.; Goswami, D.Y.

    1995-01-01

    Solar ultraviolet (UV) photocatalyzed oxidation of chemicals with titanium dioxide (TiO 2 ) has received considerable attention. Much less recognized, however, is the ability of the same system to destroy bacteria. This study examined this phenomenon and the conditions that affect it. Bacteria in aqueous solution were given solar exposure with titanium dioxide and their survival with time was determined. Lamps with a predominantly solar ultraviolet spectrum were also used in the experiments. Without exposure to UV light, TiO 2 had no deleterious effect on the bacteria. However, several common bacteria on solar exposure in the presence of TiO 2 were killed in just a few minutes, whereas without TiO 2 it took over an hour to destroy them. A concentration of 0.01% TiO 2 was most effective in killing bacteria and 10-fold concentrations lower or higher were successively less effective. Inorganic and organic compounds in solution, even in small amounts, interfered with the efficiency of killing. Alkaline solution also reduced the bactericidal activity. Circulation and agitation provided by stirring to keep the TiO 2 particles suspended reduced the time necessary to kill the bacteria. Time-intensity curves for killing bacteria were the same general shape with or without TiO 2 , indicating that TiO 2 served merely as a catalyst to increase the rate of the reaction but that the mechanism of action was not changed. The shape of the curves show that the organisms are sensitized with a minimum intensity of radiation and that an increase doesn't greatly increase the rate of kill. Below this critical intensity, however, the time required for killing markedly increases as the intensity is decreased

  9. Using Bacteria to Store Renewable Energy (Text Version) | News | NREL

    Science.gov (United States)

    Using Bacteria to Store Renewable Energy (Text Version) Using Bacteria to Store Renewable Energy is a text version of the video entitled "Using Bacteria to Store Renewable Energy." ; Bacteria from some of the Earth's harshest environments now have a new home at NREL. [A natural spring has

  10. Rapid diagnostics of the bacteria in air

    Energy Technology Data Exchange (ETDEWEB)

    Belov Nikolai, N. [ATECH KFT, Budapest (Hungary)

    2000-07-01

    Presence of the bacteria and viruses in the air is great problem now. Terrorists are going to use the bacteria weapon. Now biotechnology provides very cheap equipment ({approx} $500) for modification of the bacteria sorts. It may be used for receiving of new variants of the bacteriological weapon. And presence of one small bacteria aerosol generator in the international airport during several days will start the dangerous epidemic incidence the entire world. From another side - poor countries with hot and wet weather are continuously producing new and new dangerous bacteria. Every year epidemic waves of influence are going from China, India or Africa. And once up a time it will be epidemic explosive with fast lethal finish. Methods of estimation of the bio-aerosols in Air of City are very poor. Standard Bio-aerosol sampler has two conflicting demands. From one side the bio-sampler needs in great air volume of sample with great efficiency of separation of aerosol particles from measured air. From another side all selected particles needs in great care. This demand carried out from method of measurement of bacteria in sample by counting of colonies that grew from bacteria on nutrient media after incubation time. It is a problem to prevent bacterial flora from death during collecting aerosol sample. This time of growth and counting of colony is so long that result of this measurement will be unusable if it will be terrorist action of start of bacteriological was. Here presented new methods for fast diagnostics of the bacteria in the air. It consists from 4 general parts: (1) Micro-droplet method for diagnostics of biological active substances in aerosol sample. This method allows to control the bio-particle position on the plate, to use series of biochemistry species for analytical reaction for this small bio-particle. Small volume of biochemical reaction reduces noise. This method provides extremely high sensitivity for discovering of biological material. (2

  11. Modulation of immune homeostasis by commensal bacteria

    Science.gov (United States)

    Ivanov, Ivaylo I.; Littman, Dan R.

    2011-01-01

    Intestinal bacteria form a resident community that has co-evolved with the mammalian host. In addition to playing important roles in digestion and harvesting energy, commensal bacteria are crucial for the proper functioning of mucosal immune defenses. Most of these functions have been attributed to the presence of large numbers of “innocuous” resident bacteria that dilute or occupy niches for intestinal pathogens or induce innate immune responses that sequester bacteria in the lumen, thus quenching excessive activation of the mucosal immune system. However it has recently become obvious that commensal bacteria are not simply beneficial bystanders, but are important modulators of intestinal immune homeostasis and that the composition of the microbiota is a major factor in pre-determining the type and robustness of mucosal immune responses. Here we review specific examples of individual members of the microbiota that modify innate and adaptive immune responses, and we focus on potential mechanisms by which such species-specific signals are generated and transmitted to the host immune system. PMID:21215684

  12. Molecular analysis of deep subsurface bacteria

    International Nuclear Information System (INIS)

    Jimenez Baez, L.E.

    1989-09-01

    Deep sediments samples from site C10a, in Appleton, and sites, P24, P28, and P29, at the Savannah River Site (SRS), near Aiken, South Carolina were studied to determine their microbial community composition, DNA homology and mol %G+C. Different geological formations with great variability in hydrogeological parameters were found across the depth profile. Phenotypic identification of deep subsurface bacteria underestimated the bacterial diversity at the three SRS sites, since bacteria with the same phenotype have different DNA composition and less than 70% DNA homology. Total DNA hybridization and mol %G+C analysis of deep sediment bacterial isolates suggested that each formation is comprised of different microbial communities. Depositional environment was more important than site and geological formation on the DNA relatedness between deep subsurface bacteria, since more 70% of bacteria with 20% or more of DNA homology came from the same depositional environments. Based on phenotypic and genotypic tests Pseudomonas spp. and Acinetobacter spp.-like bacteria were identified in 85 million years old sediments. This suggests that these microbial communities might have been adapted during a long period of time to the environmental conditions of the deep subsurface

  13. Overlapping riboflavin supply pathways in bacteria.

    Science.gov (United States)

    García-Angulo, Víctor Antonio

    2017-03-01

    Riboflavin derivatives are essential cofactors for a myriad of flavoproteins. In bacteria, flavins importance extends beyond their role as intracellular protein cofactors, as secreted flavins are a key metabolite in a variety of physiological processes. Bacteria obtain riboflavin through the endogenous riboflavin biosynthetic pathway (RBP) or by the use of importer proteins. Bacteria frequently encode multiple paralogs of the RBP enzymes and as for other micronutrient supply pathways, biosynthesis and uptake functions largely coexist. It is proposed that bacteria shut down biosynthesis and would rather uptake riboflavin when the vitamin is environmentally available. Recently, the overlap of riboflavin provisioning elements has gained attention and the functions of duplicated paralogs of RBP enzymes started to be addressed. Results point towards the existence of a modular structure in the bacterial riboflavin supply pathways. Such structure uses subsets of RBP genes to supply riboflavin for specific functions. Given the importance of riboflavin in intra and extracellular bacterial physiology, this complex array of riboflavin provision pathways may have developed to contend with the various riboflavin requirements. In riboflavin-prototrophic bacteria, riboflavin transporters could represent a module for riboflavin provision for particular, yet unidentified processes, rather than substituting for the RBP as usually assumed.

  14. Bacteria and plutonium in marine environments

    International Nuclear Information System (INIS)

    Carey, A.E.; Bowen, V.T.

    1978-01-01

    Microbes are important in geochemical cycling of many elements. Recent reports emphasize biogenous particulates and bacterial exometabolites as controlling oceanic distribution of plutonium. Bacteria perform oxidation/reduction reactions on metals such as mercury, nickel, lead, copper, and cadmium. Redox transformations or uptake of Pu by marine bacteria may well proceed by similar mechanisms. Profiles of water samples and sediment cores were obtained along the continental shelf off Nova Scotia and in the Gulf of St. Lawrence. Profiles of water samples, and sediment cores were obtained. Epifluorescent microscopy was used to view bacteria (from water or sediment) after concentration on membrane filters and staining with acridine orange. Radiochemical analyses measured Pu in sediments and water samples. Studies of 237 Pu uptake used a strain of Leucothrix mucor isolated from a macroalga. Enumeration shows bacteria to range 10 4 to 10 5 cells/ml in seawater or 10 7 to 10 8 cells/gram of sediment. These numbers are related to the levels and distrbution of Pu in the samples. In cultures of L. mucor amended with Pu atom concentrations approximating those present in open ocean environments, bacterial cells concentrated 237 Pu slower and to lower levels than did clay minerals, glass beads, or phytoplankton. These data further clarify the role of marine bacteria in Pu biogeochemistry

  15. Marine Pseudomonas putida: a potential source of antimicrobial substances against antibiotic-resistant bacteria

    Directory of Open Access Journals (Sweden)

    Palloma Rodrigues Marinho

    2009-08-01

    Full Text Available Bacteria isolated from marine sponges found off the coast of Rio de Janeiro, Brazil, were screened for the production of antimicrobial substances. We report a new Pseudomonas putida strain (designated P. putida Mm3 isolated from the sponge Mycale microsigmatosa that produces a powerful antimicrobial substance active against multidrug-resistant bacteria. P. putida Mm3 was identified on the basis of 16S rRNA gene sequencing and phenotypic tests. Molecular typing for Mm3 was performed by RAPD-PCR and comparison of the results to other Pseudomonas strains. Our results contribute to the search for new antimicrobial agents, an important strategy for developing alternative therapies to treat infections caused by multidrug-resistant bacteria.

  16. Marine Pseudomonas putida: a potential source of antimicrobial substances against antibiotic-resistant bacteria.

    Science.gov (United States)

    Marinho, Palloma Rodrigues; Moreira, Ana Paula Barbosa; Pellegrino, Flávia Lúcia Piffano Costa; Muricy, Guilherme; Bastos, Maria do Carmo de Freire; Santos, Kátia Regina Netto dos; Giambiagi-deMarval, Marcia; Laport, Marinella Silva

    2009-08-01

    Bacteria isolated from marine sponges found off the coast of Rio de Janeiro, Brazil, were screened for the production of antimicrobial substances. We report a new Pseudomonas putida strain (designated P. putida Mm3) isolated from the sponge Mycale microsigmatosa that produces a powerful antimicrobial substance active against multidrug-resistant bacteria. P. putida Mm3 was identified on the basis of 16S rRNA gene sequencing and phenotypic tests. Molecular typing for Mm3 was performed by RAPD-PCR and comparison of the results to other Pseudomonas strains. Our results contribute to the search for new antimicrobial agents, an important strategy for developing alternative therapies to treat infections caused by multidrug-resistant bacteria.

  17. Treatment of high-salinity chemical wastewater by indigenous bacteria--bioaugmented contact oxidation.

    Science.gov (United States)

    Li, Qiang; Wang, Mengdi; Feng, Jun; Zhang, Wei; Wang, Yuanyuan; Gu, Yanyan; Song, Cunjiang; Wang, Shufang

    2013-09-01

    A 90 m(3) biological contact oxidation system in chemical factory was bioaugmented with three strains of indigenous salt-tolerant bacteria. These three strains were screened from contaminative soil in situ. Their activity of growth and degradation was investigated with lab-scale experiments. Their salt-tolerant mechanism was confirmed to be compatible-solutes strategy for moderately halophilic bacteria, with amino acid and betaine playing important roles. The running conditions of the system were recorded for 150 days. The indigenous bacteria had such high suitability that the reactor got steady rapidly and the removal of COD maintained above 90%. It was introduced that biofilm fragments in sedimentation tank were inversely flowed to each reaction tank, and quantitative PCR demonstrated that this process could successfully maintain the bacterial abundance in the reaction tanks. In addition, the T-RFLP revealed that bioaugmented strains dominated over others in the biofilm. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Coevolution with bacteria drives the evolution of aerobic fermentation in Lachancea kluyveri.

    Directory of Open Access Journals (Sweden)

    Nerve Zhou

    Full Text Available The Crabtree positive yeasts, such as Saccharomyces cerevisiae, prefer fermentation to respiration, even under fully aerobic conditions. The selective pressures that drove the evolution of this trait remain controversial because of the low ATP yield of fermentation compared to respiration. Here we propagate experimental populations of the weak-Crabtree yeast Lachancea kluyveri, in competitive co-culture with bacteria. We find that L. kluyveri adapts by producing quantities of ethanol lethal to bacteria and evolves several of the defining characteristics of Crabtree positive yeasts. We use precise quantitative analysis to show that the rate advantage of fermentation over aerobic respiration is insufficient to provide an overall growth advantage. Thus, the rapid consumption of glucose and the utilization of ethanol are essential for the success of the aerobic fermentation strategy. These results corroborate that selection derived from competition with bacteria could have provided the impetus for the evolution of the Crabtree positive trait.

  19. Method of Detecting Coliform Bacteria and Escherichia Coli Bacteria from Reflected Light

    Science.gov (United States)

    Vincent, Robert (Inventor)

    2013-01-01

    The present invention relates to a method of detecting coliform bacteria in water from reflected light and a method of detecting Eschericha Coli bacteria in water from reflected light, and also includes devices for the measurement, calculation and transmission of data relating to that method.

  20. COMPETITION BETWEEN ANOXYGENIC PHOTOTROPHIC BACTERIA AND COLORLESS SULFUR BACTERIA IN A MICROBIAL MAT

    NARCIS (Netherlands)

    VISSCHER, PT; VANDENENDE, FP; SCHAUB, BEM; VANGEMERDEN, H

    The populations of chemolithoautotrophic (colorless) sulfur bacteria and anoxygenic phototrophic bacteria were enumerated in a marine microbial mat. The highest population densities were found in the 0-5 mm layer of the mat: 2.0 X 10(9) cells CM-3 sediment, and 4.0 X 10(7) cells cm-3 sediment for

  1. Mathematical model of rhamnolipid production using E.coli bacteria

    Science.gov (United States)

    Adham, Muhammad Fariduddin; Apri, Mochamad; Moeis, Maelita Ramdani

    2018-03-01

    Rhamnolipid is one of biosurfactants that is widely used in many industries. Despite its wide use, production of rhamnolipid usually involves a pathogen that may endanger our health. To tackle this issue, in iGEM (International Genetically Engineered Machine) competition 2015, our team engineered Escherichia coli (E.coli) to produce rhamnolipid. The bacteria were then put into medium containing glucose and lactose. It turned out that bacteria E. coli produced lower rhamnolipid than that by pseudomonas, therefore a good strategy is required to improve their productivity. We present a mathematical model to describe the production of rhamnolipid by the engineered E coli. Using bifurcation analysis, the equilibrium points of the model and their stabilities were analyzed as the amount of lactose was varied. We show that the system produces bistability behavior for some interval values of lactose. From this analysis we found that to guarantee a high production of rhamnolipid, a high level of lactose is required. To maintain the productivity, however, it is sufficient to maintain the lactose level above a certain threshold value.

  2. Elevated Rate of Genome Rearrangements in Radiation-Resistant Bacteria.

    Science.gov (United States)

    Repar, Jelena; Supek, Fran; Klanjscek, Tin; Warnecke, Tobias; Zahradka, Ksenija; Zahradka, Davor

    2017-04-01

    A number of bacterial, archaeal, and eukaryotic species are known for their resistance to ionizing radiation. One of the challenges these species face is a potent environmental source of DNA double-strand breaks, potential drivers of genome structure evolution. Efficient and accurate DNA double-strand break repair systems have been demonstrated in several unrelated radiation-resistant species and are putative adaptations to the DNA damaging environment. Such adaptations are expected to compensate for the genome-destabilizing effect of environmental DNA damage and may be expected to result in a more conserved gene order in radiation-resistant species. However, here we show that rates of genome rearrangements, measured as loss of gene order conservation with time, are higher in radiation-resistant species in multiple, phylogenetically independent groups of bacteria. Comparison of indicators of selection for genome organization between radiation-resistant and phylogenetically matched, nonresistant species argues against tolerance to disruption of genome structure as a strategy for radiation resistance. Interestingly, an important mechanism affecting genome rearrangements in prokaryotes, the symmetrical inversions around the origin of DNA replication, shapes genome structure of both radiation-resistant and nonresistant species. In conclusion, the opposing effects of environmental DNA damage and DNA repair result in elevated rates of genome rearrangements in radiation-resistant bacteria. Copyright © 2017 Repar et al.

  3. Genetic tools for the investigation of Roseobacter clade bacteria

    Directory of Open Access Journals (Sweden)

    Tielen Petra

    2009-12-01

    Full Text Available Abstract Background The Roseobacter clade represents one of the most abundant, metabolically versatile and ecologically important bacterial groups found in marine habitats. A detailed molecular investigation of the regulatory and metabolic networks of these organisms is currently limited for many strains by missing suitable genetic tools. Results Conjugation and electroporation methods for the efficient and stable genetic transformation of selected Roseobacter clade bacteria including Dinoroseobacter shibae, Oceanibulbus indolifex, Phaeobacter gallaeciensis, Phaeobacter inhibens, Roseobacter denitrificans and Roseobacter litoralis were tested. For this purpose an antibiotic resistance screening was performed and suitable genetic markers were selected. Based on these transformation protocols stably maintained plasmids were identified. A plasmid encoded oxygen-independent fluorescent system was established using the flavin mononucleotide-based fluorescent protein FbFP. Finally, a chromosomal gene knockout strategy was successfully employed for the inactivation of the anaerobic metabolism regulatory gene dnr from D. shibae DFL12T. Conclusion A genetic toolbox for members of the Roseobacter clade was established. This provides a solid methodical basis for the detailed elucidation of gene regulatory and metabolic networks underlying the ecological success of this group of marine bacteria.

  4. Manipulation of Host Cholesterol by Obligate Intracellular Bacteria

    Directory of Open Access Journals (Sweden)

    Dhritiman Samanta

    2017-05-01

    Full Text Available Cholesterol is a multifunctional lipid that plays important metabolic and structural roles in the eukaryotic cell. Despite having diverse lifestyles, the obligate intracellular bacterial pathogens Chlamydia, Coxiella, Anaplasma, Ehrlichia, and Rickettsia all target cholesterol during host cell colonization as a potential source of membrane, as well as a means to manipulate host cell signaling and trafficking. To promote host cell entry, these pathogens utilize cholesterol-rich microdomains known as lipid rafts, which serve as organizational and functional platforms for host signaling pathways involved in phagocytosis. Once a pathogen gains entrance to the intracellular space, it can manipulate host cholesterol trafficking pathways to access nutrient-rich vesicles or acquire membrane components for the bacteria or bacteria-containing vacuole. To acquire cholesterol, these pathogens specifically target host cholesterol metabolism, uptake, efflux, and storage. In this review, we examine the strategies obligate intracellular bacterial pathogens employ to manipulate cholesterol during host cell colonization. Understanding how obligate intracellular pathogens target and use host cholesterol provides critical insight into the host-pathogen relationship.

  5. Simultaneous transcriptional profiling of bacteria and their host cells.

    Directory of Open Access Journals (Sweden)

    Michael S Humphrys

    Full Text Available We developed an RNA-Seq-based method to simultaneously capture prokaryotic and eukaryotic expression profiles of cells infected with intracellular bacteria. As proof of principle, this method was applied to Chlamydia trachomatis-infected epithelial cell monolayers in vitro, successfully obtaining transcriptomes of both C. trachomatis and the host cells at 1 and 24 hours post-infection. Chlamydiae are obligate intracellular bacterial pathogens that cause a range of mammalian diseases. In humans chlamydiae are responsible for the most common sexually transmitted bacterial infections and trachoma (infectious blindness. Disease arises by adverse host inflammatory reactions that induce tissue damage & scarring. However, little is known about the mechanisms underlying these outcomes. Chlamydia are genetically intractable as replication outside of the host cell is not yet possible and there are no practical tools for routine genetic manipulation, making genome-scale approaches critical. The early timeframe of infection is poorly understood and the host transcriptional response to chlamydial infection is not well defined. Our simultaneous RNA-Seq method was applied to a simplified in vitro model of chlamydial infection. We discovered a possible chlamydial strategy for early iron acquisition, putative immune dampening effects of chlamydial infection on the host cell, and present a hypothesis for Chlamydia-induced fibrotic scarring through runaway positive feedback loops. In general, simultaneous RNA-Seq helps to reveal the complex interplay between invading bacterial pathogens and their host mammalian cells and is immediately applicable to any bacteria/host cell interaction.

  6. Solubilization of plutonium hydrous oxide by iron-reducing bacteria

    International Nuclear Information System (INIS)

    Rusin, P.A.; Quintana, L.; Brainard, J.R.; Strietelmeler, B.A.; Tait, C.D.; Ekberg, S.A.; Palmer, P.D.; Newton, T.W.; Clark, D.L.

    1994-01-01

    The removal of plutonium from soils id challenging because of its strong sorption to soils and limited solubility, Microbial reduction of metals is known to affect the speciation and solubility of sparingly soluble metals in the environment, notably iron and manganese. The similarity in reduction potential for α-FeOOH(s) and hydrous PuO 2 (s) suggests that iron-reducing bacteria may also reduce and solubilize plutonium. Bacillus strains were used to demonstrate that iron-reducing bacteria mediate the solubilization of hydrous PuO 2 (s) under anaerobic conditions. Up to ∼90% of the PuO 2 was biosolubilized in the presence of nitrilotriacetic acid (NTA) within 6-7 days. Biosolubilization occurred to a lesser extent (∼ 40%) in the absence of NTA. Little PuO 2 solubilization occurred in sterile culture media or in the presence of a non-iron-reducing Escherichia coli. These observations suggest a potentially attractive, environmentally benign strategy for the remediation of Pu-contaminated soils. 26 refs., 5 figs., 2 tabs

  7. Primordial-like enzymes from bacteria with reduced genomes.

    Science.gov (United States)

    Ferla, Matteo P; Brewster, Jodi L; Hall, Kelsi R; Evans, Gary B; Patrick, Wayne M

    2017-08-01

    The first cells probably possessed rudimentary metabolic networks, built using a handful of multifunctional enzymes. The promiscuous activities of modern enzymes are often assumed to be relics of this primordial era; however, by definition these activities are no longer physiological. There are many fewer examples of enzymes using a single active site to catalyze multiple physiologically-relevant reactions. Previously, we characterized the promiscuous alanine racemase (ALR) activity of Escherichia coli cystathionine β-lyase (CBL). Now we have discovered that several bacteria with reduced genomes lack alr, but contain metC (encoding CBL). We characterized the CBL enzymes from three of these: Pelagibacter ubique, the Wolbachia endosymbiont of Drosophila melanogaster (wMel) and Thermotoga maritima. Each is a multifunctional CBL/ALR. However, we also show that CBL activity is no longer required in these bacteria. Instead, the wMel and T. maritima enzymes are physiologically bi-functional alanine/glutamate racemases. They are not highly active, but they are clearly sufficient. Given the abundance of the microorganisms using them, we suggest that much of the planet's biochemistry is carried out by enzymes that are quite different from the highly-active exemplars usually found in textbooks. Instead, primordial-like enzymes may be an essential part of the adaptive strategy associated with streamlining. © 2017 The Authors. Molecular Microbiology Published by John Wiley & Sons Ltd.

  8. Adhesion Properties of Lactic Acid Bacteria on Intestinal Mucin

    Directory of Open Access Journals (Sweden)

    Keita Nishiyama

    2016-09-01

    Full Text Available Lactic acid bacteria (LAB are Gram-positive bacteria that are natural inhabitants of the gastrointestinal (GI tracts of mammals, including humans. Since Mechnikov first proposed that yogurt could prevent intestinal putrefaction and aging, the beneficial effects of LAB have been widely demonstrated. The region between the duodenum and the terminal of the ileum is the primary region colonized by LAB, particularly the Lactobacillus species, and this region is covered by a mucus layer composed mainly of mucin-type glycoproteins. The mucus layer plays a role in protecting the intestinal epithelial cells against damage, but is also considered to be critical for the adhesion of Lactobacillus in the GI tract. Consequently, the adhesion exhibited by lactobacilli on mucin has attracted attention as one of the critical factors contributing to the persistent beneficial effects of Lactobacillus in a constantly changing intestinal environment. Thus, understanding the interactions between Lactobacillus and mucin is crucial for elucidating the survival strategies of LAB in the GI tract. This review highlights the properties of the interactions between Lactobacillus and mucin, while concomitantly considering the structure of the GI tract from a histochemical perspective.

  9. Using Fluorescent Viruses for Detecting Bacteria in Water

    Science.gov (United States)

    Tabacco, Mary Beth; Qian, Xiaohua; Russo, Jaimie A.

    2009-01-01

    A method of detecting water-borne pathogenic bacteria is based partly on established molecular-recognition and fluorescent-labeling concepts, according to which bacteria of a species of interest are labeled with fluorescent reporter molecules and the bacteria can then be detected by fluorescence spectroscopy. The novelty of the present method lies in the use of bacteriophages (viruses that infect bacteria) to deliver the fluorescent reporter molecules to the bacteria of the species of interest.

  10. Effects of ionizing radiation on bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Suhadi, F [National Atomic Energy Agency, Jakarta (Indonesia). Pasar Djumat Research Centre

    1976-10-01

    The differences of radiosensitivities among bacteria in addition to the dependence upon the species or strains also depends on the environmental condition during irradiation (temperature, medium, the presence of protective or sensitizing agents, the gas phase or atmosphere, and water activity, or degree of hydration) and on the effects of the environmental condition before and after irradiation treatment (temperature of incubation, age of culture and growth medium). In general, spores are more resistant to radiation than vegetatic bacteria, with the exception that a few cocci are the most radiation resistant bacteria (Micrococcus and Streptococcus). The application of ionizing radiation in the fields of microbiology supports the radiation sterilization of medical and pharmaceutical products. In addition, microbiological aspects of food preservation, especially radurization, radicidation, and immunization studies by using irradiated microorganisms, are also important.

  11. Hydrodynamic interaction between bacteria and passive sphere

    Science.gov (United States)

    Zhang, Bokai; Ding, Yang; Xu, Xinliang

    2017-11-01

    Understanding hydrodynamic interaction between bacteria and passive sphere is important for identifying rheological properties of bacterial and colloidal suspension. Over the past few years, scientists mainly focused on bacterial influences on tracer particle diffusion or hydrodynamic capture of a bacteria around stationary boundary. Here, we use superposition of singularities and regularized method to study changes in bacterial swimming velocity and passive sphere diffusion, simultaneously. On this basis, we present a simple two-bead model that gives a unified interpretation of passive sphere diffusion and bacterial swimming. The model attributes both variation of passive sphere diffusion and changes of speed of bacteria to an effective mobility. Using the effective mobility of bacterial head and tail as an input function, the calculations are consistent with simulation results at a broad range of tracer diameters, incident angles and bacterial shapes.

  12. Interactions among sulfide-oxidizing bacteria

    Science.gov (United States)

    Poplawski, R.

    1985-01-01

    The responses of different phototrophic bacteria in a competitive experimental system are studied, one in which primary factors such as H2S or light limited photometabolism. Two different types of bacteria shared one limited source of sulfide under specific conditions of light. The selection of a purple and a green sulfur bacteria and the cyanobacterium was based on their physiological similarity and also on the fact that they occur together in microbial mats. They all share anoxygenic photosynthesis, and are thus probably part of an evolutionary continuum of phototrophic organisms that runs from, strictly anaerobic physiology to the ability of some cyanobacteria to shift between anoxygenic bacterial style photosynthesis and the oxygenic kind typical of eukaryotes.

  13. Copper tolerance and virulence in bacteria

    Science.gov (United States)

    Ladomersky, Erik; Petris, Michael J.

    2015-01-01

    Copper (Cu) is an essential trace element for all aerobic organisms. It functions as a cofactor in enzymes that catalyze a wide variety of redox reactions due to its ability to cycle between two oxidation states, Cu(I) and Cu(II). This same redox property of copper has the potential to cause toxicity if copper homeostasis is not maintained. Studies suggest that the toxic properties of copper are harnessed by the innate immune system of the host to kill bacteria. To counter such defenses, bacteria rely on copper tolerance genes for virulence within the host. These discoveries suggest bacterial copper intoxication is a component of host nutritional immunity, thus expanding our knowledge of the roles of copper in biology. This review summarizes our current understanding of copper tolerance in bacteria, and the extent to which these pathways contribute to bacterial virulence within the host. PMID:25652326

  14. Lethal photosensitization of biofilm-grown bacteria

    Science.gov (United States)

    Wilson, Michael

    1997-12-01

    Antibacterial agents are increasingly being used for the prophylaxis and treatment of oral diseases. As these agents can be rendered ineffective by resistance development in the target organisms there is a need to develop alternative antimicrobial approaches. Light-activated antimicrobial agents release singlet oxygen and free radicals which can kill adjacent bacteria and a wide range of cariogenic and periodontopathogenic bacteria has been shown to be susceptible to such agents. In the oral cavity these organisms are present as biofilms (dental plaques) which are less susceptible to traditional antimicrobial agents than bacterial suspensions. The results of these studies have shown that biofilm-grown oral bacteria are also susceptible to lethal photosensitization although the light energy doses required are grater than those needed to kill the organisms when they are grown as aqueous suspensions.

  15. Gastric spiral bacteria in small felids.

    Science.gov (United States)

    Kinsel, M J; Kovarik, P; Murnane, R D

    1998-06-01

    Nine small cats, including one bobcat (Felis rufus), one Pallas cat (F. manul), one Canada lynx (F. lynx canadensis), two fishing cats (F. viverrina), two margays (F. wiedii), and two sand cats (F. margarita), necropsied between June 1995 and March 1997 had large numbers of gastric spiral bacteria, whereas five large cats, including one African lion (Panthera leo), two snow leopards (P. uncia), one Siberian tiger (P. tigris altaica), and one jaguar (P. onca), necropsied during the same period had none. All of the spiral organisms from the nine small cats were histologically and ultrastructurally similar. Histologically, the spiral bacteria were 5-14 microm long with five to nine coils per organism and were located both extracellularly within gastric glands and surface mucus, and intracellularly in parietal cells. Spiral bacteria in gastric mucosal scrapings from the Canada lynx, one fishing cat, and the two sand cats were gram negative and had corkscrewlike to tumbling motility when viewed with phase contrast microscopy. The bacteria were 0.5-0.7 microm wide, with a periodicity of 0.65-1.1 microm in all cats. Bipolar sheathed flagella were occasionally observed, and no periplasmic fibrils were seen. The bacteria were extracellular in parietal cell canaliculi and intracellular within parietal cells. Culture of mucosal scrapings from the Canada lynx and sand cats was unsuccessful. Based on morphology, motility, and cellular tropism, the bacteria were probably Helicobacter-like organisms. Although the two margays had moderate lymphoplasmacytic gastritis, the other cats lacked or had only mild gastric lymphoid infiltrates, suggesting that these organisms are either commensals or opportunistic pathogens.

  16. Exogenous fatty acid metabolism in bacteria.

    Science.gov (United States)

    Yao, Jiangwei; Rock, Charles O

    2017-10-01

    Bacterial type II fatty acid synthesis (FASII) is a target for novel antibiotic development. All bacteria encode for mechanisms to incorporate exogenous fatty acids, and some bacteria can use exogenous fatty acids to bypass FASII inhibition. Bacteria encode three different mechanisms for activating exogenous fatty acids for incorporation into phospholipid synthesis. Exogenous fatty acids are converted into acyl-CoA in Gammaproteobacteria such as E. coli. Acyl-CoA molecules constitute a separate pool from endogenously synthesized acyl-ACP. Acyl-CoA can be used for phospholipid synthesis or broken down by β-oxidation, but cannot be used for lipopolysaccharide synthesis. Exogenous fatty acids are converted into acyl-ACP in some Gram-negative bacteria. The resulting acyl-ACP undergoes the same fates as endogenously synthesized acyl-ACP. Exogenous fatty acids are converted into acyl-phosphates in Gram-positive bacteria, and can be used for phospholipid synthesis or become acyl-ACP. Only the order Lactobacillales can use exogenous fatty acids to bypass FASII inhibition. FASII shuts down completely in presence of exogenous fatty acids in Lactobacillales, allowing Lactobacillales to synthesize phospholipids entirely from exogenous fatty acids. Inhibition of FASII cannot be bypassed in other bacteria because FASII is only partially down-regulated in presence of exogenous fatty acid or FASII is required to synthesize essential metabolites such as β-hydroxyacyl-ACP. Certain selective pressures such as FASII inhibition or growth in biofilms can select for naturally occurring one step mutations that attenuate endogenous fatty acid synthesis. Although attempts have been made to estimate the natural prevalence of these mutants, culture-independent metagenomic methods would provide a better estimate. Copyright © 2017 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

  17. Bacteria vs. bacteriophages: parallel evolution of immune arsenals

    Directory of Open Access Journals (Sweden)

    Muhammad Abu Bakr Shabbir

    2016-08-01

    Full Text Available Bacteriophages are the most common entities on earth and represent a constant challenge to bacterial populations. To fend off bacteriophage infection, bacteria evolved immune systems to avert phage adsorption and block invader DNA entry. They developed restriction-modification systems and mechanisms to abort infection and interfere with virion assembly, as well as newly recognized clustered regularly interspaced short palindromic repeats (CRISPR. In response to bacterial immune systems, bacteriophages synchronously evolved resistance mechanisms, such as the anti-CRISPR systems to counterattack bacterial CRISPR-cas systems, in a continuing evolutionary arms race between virus and host. In turn, it is fundamental to the survival of the bacterial cell to evolve a system to combat bacteriophage immune strategies.

  18. Genomics of lactic acid bacteria: Current status and potential applications.

    Science.gov (United States)

    Wu, Chongde; Huang, Jun; Zhou, Rongqing

    2017-08-01

    Lactic acid bacteria (LAB) are widely used for the production of a variety of foods and feed raw materials where they contribute to flavor and texture of the fermented products. In addition, specific LAB strains are considered as probiotic due to their health-promoting effects in consumers. Recently, the genome sequencing of LAB is booming and the increased amount of published genomics data brings unprecedented opportunity for us to reveal the important traits of LAB. This review describes the recent progress on LAB genomics and special emphasis is placed on understanding the industry-related physiological features based on genomics analysis. Moreover, strategies to engineer metabolic capacity and stress tolerance of LAB with improved industrial performance are also discussed.

  19. Differential staining of bacteria: gram stain.

    Science.gov (United States)

    Moyes, Rita B; Reynolds, Jackie; Breakwell, Donald P

    2009-11-01

    In 1884, Hans Christian Gram, a Danish doctor, developed a differential staining technique that is still the cornerstone of bacterial identification and taxonomic division. This multistep, sequential staining protocol separates bacteria into four groups based on cell morphology and cell wall structure: Gram-positive cocci, Gram-negative cocci, Gram-positive rods, and Gram-negative rods. The Gram stain is useful for assessing bacterial contamination of tissue culture samples or for examining the Gram stain status and morphological features of bacteria isolated from mixed or isolated bacterial cultures. (c) 2009 by John Wiley & Sons, Inc.

  20. Motile bacteria in a critical fluid mixture

    Science.gov (United States)

    Koumakis, Nick; Devailly, Clémence; Poon, Wilson C. K.

    2018-06-01

    We studied the swimming of Escherichia coli bacteria in the vicinity of the critical point in a solution of the nonionic surfactant C12E5 in buffer solution. In phase-contrast microscopy, each swimming cell produces a transient trail behind itself lasting several seconds. Comparing quantitative image analysis with simulations show that these trails are due to local phase reorganization triggered by differential adsorption. This contrasts with similar trails seen in bacteria swimming in liquid crystals, which are due to shear effects. We show how our trails are controlled, and use them to probe the structure and dynamics of critical fluctuations in the fluid medium.

  1. Bacteria Provide Cleanup of Oil Spills, Wastewater

    Science.gov (United States)

    2010-01-01

    Through Small Business Innovation Research (SBIR) contracts with Marshall Space Flight Center, Micro-Bac International Inc., of Round Rock, Texas, developed a phototrophic cell for water purification in space. Inside the cell: millions of photosynthetic bacteria. Micro-Bac proceeded to commercialize the bacterial formulation it developed for the SBIR project. The formulation is now used for the remediation of wastewater systems and waste from livestock farms and food manufacturers. Strains of the SBIR-derived bacteria also feature in microbial solutions that treat environmentally damaging oil spills, such as that resulting from the catastrophic 2010 Deepwater Horizon oil rig explosion in the Gulf of Mexico.

  2. Functional Encyclopedia of Bacteria and Archaea

    Energy Technology Data Exchange (ETDEWEB)

    Blow, M. J.; Deutschbauer, A. M.; Hoover, C. A.; Lamson, J.; Lamson, J.; Price, M. N.; Waters, J.; Wetmore, K. M.; Bristow, J.; Arkin, A. P.

    2013-03-20

    Bacteria and Archaea exhibit a huge diversity of metabolic capabilities with fundamental importance in the environment, and potential applications in biotechnology. However, the genetic bases of these capabilities remain unclear due largely to an absence of technologies that link DNA sequence to molecular function. To address this challenge, we are developing a pipeline for high throughput annotation of gene function using mutagenesis, growth assays and DNA sequencing. By applying this pipeline to annotate gene function in 50 diverse microbes we hope to discover thousands of new gene functions and produce a proof of principle `Functional Encyclopedia of Bacteria and Archaea?.

  3. Beer spoilage bacteria and hop resistance.

    Science.gov (United States)

    Sakamoto, Kanta; Konings, Wil N

    2003-12-31

    For brewing industry, beer spoilage bacteria have been problematic for centuries. They include some lactic acid bacteria such as Lactobacillus brevis, Lactobacillus lindneri and Pediococcus damnosus, and some Gram-negative bacteria such as Pectinatus cerevisiiphilus, Pectinatus frisingensis and Megasphaera cerevisiae. They can spoil beer by turbidity, acidity and the production of unfavorable smell such as diacetyl or hydrogen sulfide. For the microbiological control, many advanced biotechnological techniques such as immunoassay and polymerase chain reaction (PCR) have been applied in place of the conventional and time-consuming method of incubation on culture media. Subsequently, a method is needed to determine whether the detected bacterium is capable of growing in beer or not. In lactic acid bacteria, hop resistance is crucial for their ability to grow in beer. Hop compounds, mainly iso-alpha-acids in beer, have antibacterial activity against Gram-positive bacteria. They act as ionophores which dissipate the pH gradient across the cytoplasmic membrane and reduce the proton motive force (pmf). Consequently, the pmf-dependent nutrient uptake is hampered, resulting in cell death. The hop-resistance mechanisms in lactic acid bacteria have been investigated. HorA was found to excrete hop compounds in an ATP-dependent manner from the cell membrane to outer medium. Additionally, increased proton pumping by the membrane bound H(+)-ATPase contributes to hop resistance. To energize such ATP-dependent transporters hop-resistant cells contain larger ATP pools than hop-sensitive cells. Furthermore, a pmf-dependent hop transporter was recently presented. Understanding the hop-resistance mechanisms has enabled the development of rapid methods to discriminate beer spoilage strains from nonspoilers. The horA-PCR method has been applied for bacterial control in breweries. Also, a discrimination method was developed based on ATP pool measurement in lactobacillus cells. However

  4. CSR STRATEGIES

    OpenAIRE

    LAURENTIU BARANGA; ION STEGAROIU

    2011-01-01

    Corporate Social Responsibility (CSR) has got three components: economic responsibility of shareholders, corporate environmental responsibility, corporate responsibility of the society. Each component of the CSR has its own features, according to which adequate individual behaviour is established. Knowing these features is very important in CSR strategy development.

  5. Genomic and evolutionary comparisons of diazotrophic and pathogenic bacteria of the order Rhizobiales

    Directory of Open Access Journals (Sweden)

    Vasconcelos Ana

    2010-02-01

    Full Text Available Abstract Background Species belonging to the Rhizobiales are intriguing and extensively researched for including both bacteria with the ability to fix nitrogen when in symbiosis with leguminous plants and pathogenic bacteria to animals and plants. Similarities between the strategies adopted by pathogenic and symbiotic Rhizobiales have been described, as well as high variability related to events of horizontal gene transfer. Although it is well known that chromosomal rearrangements, mutations and horizontal gene transfer influence the dynamics of bacterial genomes, in Rhizobiales, the scenario that determine pathogenic or symbiotic lifestyle are not clear and there are very few studies of comparative genomic between these classes of prokaryotic microorganisms trying to delineate the evolutionary characterization of symbiosis and pathogenesis. Results Non-symbiotic nitrogen-fixing bacteria and bacteria involved in bioremediation closer to symbionts and pathogens in study may assist in the origin and ancestry genes and the gene flow occurring in Rhizobiales. The genomic comparisons of 19 species of Rhizobiales, including nitrogen-fixing, bioremediators and pathogens resulted in 33 common clusters to biological nitrogen fixation and pathogenesis, 15 clusters exclusive to all nitrogen-fixing bacteria and bacteria involved in bioremediation, 13 clusters found in only some nitrogen-fixing and bioremediation bacteria, 01 cluster exclusive to some symbionts, and 01 cluster found only in some pathogens analyzed. In BBH performed to all strains studied, 77 common genes were obtained, 17 of which were related to biological nitrogen fixation and pathogenesis. Phylogenetic reconstructions for Fix, Nif, Nod, Vir, and Trb showed possible horizontal gene transfer events, grouping species of different phenotypes. Conclusions The presence of symbiotic and virulence genes in both pathogens and symbionts does not seem to be the only determinant factor for lifestyle

  6. Genomic and evolutionary comparisons of diazotrophic and pathogenic bacteria of the order Rhizobiales.

    Science.gov (United States)

    Carvalho, Fabíola M; Souza, Rangel C; Barcellos, Fernando G; Hungria, Mariangela; Vasconcelos, Ana Tereza R

    2010-02-08

    Species belonging to the Rhizobiales are intriguing and extensively researched for including both bacteria with the ability to fix nitrogen when in symbiosis with leguminous plants and pathogenic bacteria to animals and plants. Similarities between the strategies adopted by pathogenic and symbiotic Rhizobiales have been described, as well as high variability related to events of horizontal gene transfer. Although it is well known that chromosomal rearrangements, mutations and horizontal gene transfer influence the dynamics of bacterial genomes, in Rhizobiales, the scenario that determine pathogenic or symbiotic lifestyle are not clear and there are very few studies of comparative genomic between these classes of prokaryotic microorganisms trying to delineate the evolutionary characterization of symbiosis and pathogenesis. Non-symbiotic nitrogen-fixing bacteria and bacteria involved in bioremediation closer to symbionts and pathogens in study may assist in the origin and ancestry genes and the gene flow occurring in Rhizobiales. The genomic comparisons of 19 species of Rhizobiales, including nitrogen-fixing, bioremediators and pathogens resulted in 33 common clusters to biological nitrogen fixation and pathogenesis, 15 clusters exclusive to all nitrogen-fixing bacteria and bacteria involved in bioremediation, 13 clusters found in only some nitrogen-fixing and bioremediation bacteria, 01 cluster exclusive to some symbionts, and 01 cluster found only in some pathogens analyzed. In BBH performed to all strains studied, 77 common genes were obtained, 17 of which were related to biological nitrogen fixation and pathogenesis. Phylogenetic reconstructions for Fix, Nif, Nod, Vir, and Trb showed possible horizontal gene transfer events, grouping species of different phenotypes. The presence of symbiotic and virulence genes in both pathogens and symbionts does not seem to be the only determinant factor for lifestyle evolution in these microorganisms, although they may act in

  7. [Bacterial biofilms as a natural form of existence of bacteria in the environment and host organism].

    Science.gov (United States)

    Romanova, Iu M; Gintsburg, A L

    2011-01-01

    Advances in microscopic analysis and molecular genetics research methods promoted the acquisition of evidence that natural bacteria populations exist predominately as substrate attached biofilms. Bacteria in biofilms are able to exchange signals and display coordinated activity that is inherent to multicellular organisms. Formation of biofilm communities turned out to be one of the main survival strategies of bacteria in their ecological niche. Bacteria in attached condition in biofilm are protected from the environmental damaging factors and effects of antibacterial substances in the environment and host organism during infection. According to contemporary conception, biofilm is a continuous layer of bacterial cells that are attached to a surface and each other, and contained in a biopolymer matrix. Such bacterial communities may be composed of bacteria of one or several species, and composed of actively functioning cells as well as latent and uncultured forms. Particular attention has recently been paid to the role of biofilms in the environment and host organism. Microorganisms form biofilm on any biotic and abiotic surfaces which creates serious problems in medicine and various areas of economic activity. Currently, it is established that biofilms are one of the pathogenetic factors of chronic inflection process formation. The review presents data on ubiquity of bacteria existence as biofilms, contemporary methods of microbial community analysis, structural-functional features of bacterial biofilms. Particular attention is paid to the role of biofilm in chronic infection process formation, heightened resistance to antibiotics of bacteria in biofilms and possible mechanisms of resistance. Screening approaches for agents against biofilms in chronic infections are discussed.

  8. The inhibitory effects of free ammonia on ammonia oxidizing bacteria and nitrite oxidizing bacteria under anaerobic condition.

    Science.gov (United States)

    Qian, Wenting; Peng, Yongzhen; Li, Xiyao; Zhang, Qiong; Ma, Bin

    2017-11-01

    The free ammonia (FA) inhibition on ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) under anaerobic condition was investigated in this study. The results indicated that NOB was more sensitive to the FA anaerobic treatment than AOB. The FA anaerobic inhibition on nitrifier gradually heightened with the increase of FA concentration. Accompanied with FA concentration increase from 0 to 16.82mgNH 3 -N·L -1 (the highest concentration adopted in this study), the activity of AOB reduced by 15.9%, while NOB decreased by 29.2%. After FA anaerobic treatment, nitrite was accumulated during nitrification. However, the nitrite accumulation disappeared on the sixth cycle of activity recovery tests with excessive aeration. Based on this result, a novel strategy for achieving nitritation is proposed, which involves recirculating a portion of the activated sludge through a side-line sludge treatment unit, where the sludge is subjected to treatment with FA under anaerobic condition. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Protein aggregation in bacteria: the thin boundary between functionality and toxicity.

    Science.gov (United States)

    Bednarska, Natalia G; Schymkowitz, Joost; Rousseau, Frederic; Van Eldere, Johan

    2013-09-01

    Misfolding and aggregation of proteins have a negative impact on all living organisms. In recent years, aggregation has been studied in detail due to its involvement in neurodegenerative diseases, including Alzheimer's, Parkinson's and Huntington's diseases, and type II diabetes--all associated with accumulation of amyloid fibrils. This research highlighted the central importance of protein homeostasis, or proteostasis for short, defined as the cellular state in which the proteome is both stable and functional. It implicates an equilibrium between synthesis, folding, trafficking, aggregation, disaggregation and degradation. In accordance with the eukaryotic systems, it has been documented that protein aggregation also reduces fitness of bacterial cells, but although our understanding of the cellular protein quality control systems is perhaps most detailed in bacteria, the use of bacterial proteostasis as a drug target remains little explored. Here we describe protein aggregation as a normal physiological process and its role in bacterial virulence and we shed light on how bacteria defend themselves against the toxic threat of aggregates. We review the impact of aggregates on bacterial viability and look at the ways that bacteria use to maintain a balance between aggregation and functionality. The proteostasis in bacteria can be interrupted via overexpression of proteins, certain antibiotics such as aminoglycosides, as well as antimicrobial peptides--all leading to loss of cell viability. Therefore intracellular protein aggregation and disruption of proteostatic balance in bacteria open up another strategy that should be explored towards the discovery of new antimicrobials.

  10. Application of immobilized synthetic anti-lipopolysaccharide peptides for the isolation and detection of bacteria.

    Science.gov (United States)

    Sandetskaya, N; Engelmann, B; Brandenburg, K; Kuhlmeier, D

    2015-08-01

    The molecular detection of microorganisms in liquid samples generally requires their enrichment or isolation. The aim of our study was to evaluate the capture and pre-concentration of bacteria by immobilized particular cationic antimicrobial peptides, called synthetic anti-lipopolysaccharide peptides (SALP). For the proof-of-concept and screening of different SALP, the peptides were covalently immobilized on glass slides, and the binding of bacteria was confirmed by microscopic examination of the slides or their scanning, in case of fluorescent bacterial cells. The most efficient SALP was further tethered to magnetic beads. SALP beads were used for the magnetic capture of Escherichia coli in liquid samples. The efficiency of this strategy was evaluated using polymerase chain reaction (PCR). Covalently immobilized SALP were capable of capturing bacteria in liquid samples. However, PCR was hampered by the unspecific binding of DNA to the positively charged peptide. We developed a method for DNA recovery by the enzymatic digestion of the peptide, which allowed for a successful PCR, though the method had its own adverse impact on the detection and, thus, did not allow for the reliable quantitative analysis of the pathogen enrichment. Immobilized SALP can be used as capture molecules for bacteria in liquid samples and can be recommended for the design of the assays or decontamination of the fluids. For the accurate subsequent detection of bacteria, DNA-independent methods should be used.

  11. Modes of action for biological control of Botrytis cinerea by antagonistic bacteria

    Directory of Open Access Journals (Sweden)

    Rana HAIDAR

    2017-01-01

    Full Text Available The role of beneficial bacteria in biocontrol of plant diseases, particularly those caused by the necrotrophic fungus Botrytis cinerea, has been investigated by testing many bacteria under laboratory and field conditions. Bacteria may protect plants against B. cinerea by direct antagonistic interactions between biocontrol agents and this pathogen, as well as indirect effects through the induction of host resistance. This review focuses on various bacteria that act as biological control agents (BCAs of B. cinerea and their associated mechanisms. The modes of action (MoAs include: i synthesis of anti-fungal metabolites, such as antibiotics, cell wall-degrading enzymes and volatile organic compounds (VOCs; ii competition for nutrients and/or a niche; and iii induction of host resistance. The challenge for development of BCAs is to reduce the variability of efficiency and to prove persistence under a large range of conditions. We discuss the advantages and drawbacks of MoA for future applications of bacteria in the field and in post-harvest storage, as well as combination of different MoAs as a strategy to achieve a more regular efficacy.

  12. Simultaneous aptasensor for multiplex pathogenic bacteria detection based on multicolor upconversion nanoparticles labels.

    Science.gov (United States)

    Wu, Shijia; Duan, Nuo; Shi, Zhao; Fang, Congcong; Wang, Zhouping

    2014-03-18

    A highly sensitive and specific multiplex method for the simultaneous detection of three pathogenic bacteria was fabricated using multicolor upconversion nanoparticles (UCNPs) as luminescence labels coupled with aptamers as the molecular recognition elements. Multicolor UCNPs were synthesized via doping with various rare-earth ions to obtain well-separated emission peaks. The aptamer sequences were selected using the systematic evolution of ligands by exponential enrichment (SELEX) strategy for Staphylococcus aureus, Vibrio parahemolyticus, and Salmonella typhimurium. When applied in this method, aptamers can be used for the specific recognition of the bacteria from complex mixtures, including those found in real food matrixes. Aptamers and multicolor UCNPs were employed to selectively capture and simultaneously quantify the three target bacteria on the basis of the independent peaks. Under optimal conditions, the correlation between the concentration of three bacteria and the luminescence signal was found to be linear from 50-10(6) cfu mL(-1). Improved by the magnetic separation and concentration effect of Fe3O4 magnetic nanoparticles, the limits of detection of the developed method were found to be 25, 10, and 15 cfu mL(-1) for S. aureus, V. parahemolyticus, and S. typhimurium, respectively. The capability of the bioassay in real food samples was also investigated, and the results were consistent with experimental results obtained from plate-counting methods. This proposed method for the detection of various pathogenic bacteria based on multicolor UCNPs has great potential in the application of food safety and multiplex nanosensors.

  13. Pathogenic Assay of Probiotic Bacteria Producing Proteolytic Enzymes as Bioremediation Bacteria Against Vannamei Shrimp Larvae (Litopenaeus vannamei)

    OpenAIRE

    Wilis Ari Setyati; Muhammad Zainuddin; Person Pesona Renta

    2017-01-01

    Application of bacteria in bioremediation of shrimp culture ponds is one of the methods used to clean internal pollutants. This study aimed to evaluate the pathogenicity of extracellular proteolytic enzyme produced by the probiotic bacteria as bioremediation bacteria on vannamei shrimp larvae culture. There were five probiotic bacteria, which were successfully isolated from the sediments served as substrate in mangrove area. The isolated bacteria were coded in number as 13, 19, 30, 33, and 36...

  14. Granzyme B Disrupts Central Metabolism and Protein Synthesis in Bacteria to Promote an Immune Cell Death Program.

    Science.gov (United States)

    Dotiwala, Farokh; Sen Santara, Sumit; Binker-Cosen, Andres Ariel; Li, Bo; Chandrasekaran, Sriram; Lieberman, Judy

    2017-11-16

    Human cytotoxic lymphocytes kill intracellular microbes. The cytotoxic granule granzyme proteases released by cytotoxic lymphocytes trigger oxidative bacterial death by disrupting electron transport, generating superoxide anion and inactivating bacterial oxidative defenses. However, they also cause non-oxidative cell death because anaerobic bacteria are also killed. Here, we use differential proteomics to identify granzyme B substrates in three unrelated bacteria: Escherichia coli, Listeria monocytogenes, and Mycobacteria tuberculosis. Granzyme B cleaves a highly conserved set of proteins in all three bacteria, which function in vital biosynthetic and metabolic pathways that are critical for bacterial survival under diverse environmental conditions. Key proteins required for protein synthesis, folding, and degradation are also substrates, including multiple aminoacyl tRNA synthetases, ribosomal proteins, protein chaperones, and the Clp system. Because killer cells use a multipronged strategy to target vital pathways, bacteria may not easily become resistant to killer cell attack. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Effects of symbiotic bacteria on chemical sensitivity of Daphnia magna.

    Science.gov (United States)

    Manakul, Patcharaporn; Peerakietkhajorn, Saranya; Matsuura, Tomoaki; Kato, Yasuhiko; Watanabe, Hajime

    2017-07-01

    The crustacean zooplankton Daphnia magna has been widely used for chemical toxicity tests. Although abiotic factors have been well documented in ecotoxicological test protocols, biotic factors that may affect the sensitivity to chemical compounds remain limited. Recently, we identified symbiotic bacteria that are critical for the growth and reproduction of D. magna. The presence of symbiotic bacteria on Daphnia raised the question as to whether these bacteria have a positive or negative effect on toxicity tests. In order to evaluate the effects of symbiotic bacteria on toxicity tests, bacteria-free Daphnia were prepared, and their chemical sensitivities were compared with that of Daphnia with symbiotic bacteria based on an acute immobilization test. The Daphnia with symbiotic bacteria showed higher chemical resistance to nonylphenol, fenoxycarb, and pentachlorophenol than bacteria-free Daphnia. These results suggested potential roles of symbiotic bacteria in the chemical resistance of its host Daphnia. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. DOT strategies versus orbiter strategies

    NARCIS (Netherlands)

    Rutten, R.J.

    2001-01-01

    The Dutch Open Telescope is a high-resolution solar imager coming on-line at La Palma. The definition of the DOT science niche, strategies, and requirements resemble Solar Orbiter considerations and deliberations. I discuss the latter in the light of the former, and claim that multi-line observation

  17. Fermentation of D-Tagatose by Human Intestinal Bacteria and Dairy Lactic Acid Bacteria

    OpenAIRE

    Bertelsen, Hans; Andersen, Hans; Tvede, Michael

    2011-01-01

    A number of 174 normal or pathogenic human enteric bacteria and dairy lactic acid bacteria were screened for D-tagatose fermentation by incubation for 48 hours. Selection criteria for fermentation employed included a drop in pH below 5.5 and a distance to controls of more than 0.5. Only a few of the normal occurring enteric human bacteria were able to ferment D-tagatose, among those Enterococcus faecalis, Enterococcus faecium and Lactobacillus strains. D-Tagatose fermentation seems to be comm...

  18. Brilliant glyconanocapsules for trapping of bacteria.

    Science.gov (United States)

    Yan, Xibo; Sivignon, Adeline; Alcouffe, Pierre; Burdin, Béatrice; Favre-Bonté, Sabine; Bilyy, Rostyslav; Barnich, Nicolas; Fleury, Etienne; Ganachaud, François; Bernard, Julien

    2015-08-28

    Nanoprecipitation of miglyol into droplets surrounded by a functional glycopolymer generates nanocapsules of biointerest. Fluorophores are trapped in situ or post-grafted onto the crosslinked polymer shell for efficient imaging. The resulting colloids induce aggregation of bacteria through strong specific interactions and promote their facile removal.

  19. Brilliant glyconanocapsules for trapping of bacteria

    OpenAIRE

    Yan, Xibo; Sivignon, Adeline; Alcouffe, Pierre; Burdin, Béatrice; Favre-Bonté, Sabine; Bilyy, Rostyslav; Barnich, Nicolas; Fleury, Etienne; Ganachaud, François; Bernard, Julien

    2015-01-01

    Nanoprecipitation of miglyol into droplets surrounded by a functional glycopolymer generates nanocapsules of biointerest. Fluorophores are trapped in situ or post-grafted onto the crosslinked polymer shell for efficient imaging. The resulting colloids induce aggregation of bacteria through strong specific interactions and promote their facile removal.

  20. On Bunsen Burners, Bacteria and the Bible

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 2. On Bunsen Burners, Bacteria and the Bible. Milind Watve. Classroom Volume 1 Issue 2 February 1996 pp 84-89. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/001/02/0084-0089 ...

  1. Solvent-tolerant bacteria in biocatalysis.

    NARCIS (Netherlands)

    Bont, de J.A.M.

    1998-01-01

    The toxicity of fine chemicals to the producer organism is a problem in several biotechnological production processes. In several instances, an organic phase can be used to extract the toxic product from the aqueous phase during a fermentation. With the discovery of solvent-tolerant bacteria, more

  2. OCCURRENCE OF PATHOGENIC BACTERIA ASSOCIATED WITH ...

    African Journals Online (AJOL)

    USER

    With the diminishing rate of natural fish resources globally, a reasonable percentage of fish and fish products .... from these artificial fish habitat, one may not be out of place to ... condition for bacteria reproduction and development in their host ...

  3. Identification of bacteria using mass spectrometry techniques

    Czech Academy of Sciences Publication Activity Database

    Krásný, Lukáš; Hynek, R.; Hochel, I.

    2013-01-01

    Roč. 353, NOV 2013 (2013), s. 67-79 ISSN 1387-3806 R&D Projects: GA ČR GAP503/10/0664 Institutional support: RVO:61388971 Keywords : Mass spectrometry * Bacteria * Identification Subject RIV: EE - Microbiology, Virology Impact factor: 2.227, year: 2013

  4. Antimicrobial resistant bacteria in the food chain

    DEFF Research Database (Denmark)

    Wegener, Henrik Caspar

    2003-01-01

    Antimicrobials are used for treatment and prevention of disease in food animals and as feed additives for growth promotion. All uses lead to the development of resistant bacteria, some of which are pathogenic to humans. Current main concerns are with resistance in Salmonella and Campylobacter...

  5. Bioluminescent bacteria: lux genes as environmental biosensors

    OpenAIRE

    Nunes-Halldorson,Vânia da Silva; Duran,Norma Letícia

    2003-01-01

    Bioluminescent bacteria are widespread in natural environments. Over the years, many researchers have been studying the physiology, biochemistry and genetic control of bacterial bioluminescence. These discoveries have revolutionized the area of Environmental Microbiology through the use of luminescent genes as biosensors for environmental studies. This paper will review the chronology of scientific discoveries on bacterial bioluminescence and the current applications of bioluminescence in env...

  6. (VAM) and phosphate solubilizing bacteria (PSB)

    African Journals Online (AJOL)

    User

    2013-09-18

    Sep 18, 2013 ... mycorrhiza (VAM), and phosphate solubilising bacteria (PSB) individually and in .... Two-way analysis of variance (ANOVA) was carried out at a 0.05 level of significance on the data and SPSS version 13.0 was used.

  7. 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...

  8. Filamentous bacteria transport electrons over centimetre distances

    DEFF Research Database (Denmark)

    Pfeffer, Christian; Larsen, Steffen; Song, Jie

    2012-01-01

    across centimetre-wide zones. Here we present evidence that the native conductors are long, filamentous bacteria. They abounded in sediment zones with electric currents and along their length they contained strings with distinct properties in accordance with a function as electron transporters. Living...

  9. Halophilic and haloalkaliphilic sulfur-oxidizing bacteria

    NARCIS (Netherlands)

    Sorokin, D.Y.; Banciu, H.; Robertson, L.A.; Kuenen, J.G.; Muntyan, M.S.; Muyzer, G.; Rosenberg, E.; DeLong, F.; Delong, E.; Lory, S.; Stackebrandt, E.; Thompson, F.

    2013-01-01

    Chemotrophic sulfur-oxidizing bacteria (SOB) represent an important functional group of microorganisms responsible for the dark oxidation of reduced sulfur compounds generated by sulfidogens. Until recently, only a single genus of halophilic SOB (Halothiobacillus) has been described, and nothing was

  10. Identification of marine methanol-utilizing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, M; Iwaki, H; Kouno, K; Inui, T

    1980-01-01

    A taxonomical study of 65 marine methanol-utilizing bacteria is described. They were Gram-negative, non-spore-forming rods with a polar flagellum and had marine bacterial properties and required vitamin B/sub 12/ for growth. All of them assimilated fructose in addition to C/sub 1/-compounds and produced acid oxidatively from fructose. Twenty-four strains assimilated only C/sub 1/-compounds. They were resistant to penicillin, oxytetracycline and 0/129 substance (Vibrio stat), and tolerant to 12% NaCl. Guanine-cytosine contents of deoxyribonucleic acid in typical strains fell in the range of 43.8 to 47.6%. Other morphological and physiological properties were almost the same as those of terrestrial methanol-utilizers. Bacteria in the first group (41 strains) were facultative methylotrophs and were divided into three subgroups by the assimilation of methylated amines, that is, subgroup I (30 strains) assimilated mono-, di- and tri-methylamine, subgroup II (9 strains) assimilated only mono-methylamine, the bacteria of subgroups I and II were named Alteromonas thalassomethanolica sp. nov. and subgroup III (2 strains) did not assimilate methylated amines, and was tentatively assigned as Alteromonas sp. The second group of bacteria (24 strains) was obligate methylotrophs, named Methylomonas thalassica sp. nov. and was divided into subgroup IV (15 strains) which assimilated mono-, di and tri-methylamine and subgroup V (9 strains) which assimilated mono-methylamine.

  11. Bacteria Isolated from Post-Partum Infections

    Directory of Open Access Journals (Sweden)

    Nahid Arianpour

    2009-06-01

    Full Text Available Objective: This study was undertaken with an aim to determine bacterial species involved in post partum infections and also their abundance in patients admitted to at Khanevadeh hospital. In this study out of three different kinds of postpartum infections (i.e. genital, breast and urinary tract, only genital infection is considered.Materials and Methods: Post partum infection among 6077 patients (inpatients and re-admitted patients of Khanevadeh hospital from 2003 till 2008 was studied in this descriptive study. Samples were collected from patients for laboratory diagnosis to find out the causative organisms.Results: Follow up of mothers after delivery revealed 7.59% (461 patients had post partum infection, out of which 1.03% (63 patients were re-hospitalized. Infection was more often among younger mothers. Bacteria isolated and identified were both aerobic and anaerobic cocci and bacilli, majority of which were normal flora of the site of infection. Though, some pathogenic bacteria like Staphylococcus aureus, Neisseria gonorrhea, Chlamydia trachomatis,were also the causative agents. The commonest infection was infection at the site of episiotomy. Conclusion: Puerperal infection was detected in of 7.59% mothers. Bacteria isolated were both aerobic and anaerobic cocci and bacilli, majority of which were normal flora. However; some pathogenic bacteria were isolated.

  12. Serpins in unicellular Eukarya, Archaea, and Bacteria:

    DEFF Research Database (Denmark)

    Roberts, T.H.; Hejgaard, Jørn; Saunders, N.F.W

    2004-01-01

    , where serpins were found in only 4 of 13 genera, and Bacteria, in only 9 of 56 genera. The serpins from unicellular organisms appear to be phylogenetically distinct from all of the clades of higher eukaryotic serpins. Most of the sequences from unicellular organisms have the characteristics...

  13. Bacteria as transporters of phosphorus through soil

    DEFF Research Database (Denmark)

    Glæsner, N.; Bælum, Jacob; Jacobsen, C. S.

    2016-01-01

    The transport of phosphorus (P) from agricultural land has led to the eutrophication of surface waters worldwide, especially in areas with intensive animal production. In this research, we investigated the role of bacteria in the leaching of P through three agricultural soils with different...

  14. Multidrug transporters in lactic acid bacteria

    NARCIS (Netherlands)

    Mazurkiewicz, P; Sakamoto, K; Poelarends, GJ; Konings, WN

    Gram-positive lactic acid bacteria possess several Multi-Drug Resistance systems (MDRs) that excrete out of the cell a wide variety of mainly cationic lipophilic cytotoxic compounds as well as many clinically relevant antibiotics. These MDRs are either proton/drug antiporters belonging to the major

  15. Drug efflux proteins in multidrug resistant bacteria

    NARCIS (Netherlands)

    vanVeen, HW; Konings, WN

    Bacteria contain an array of transport proteins in their cytoplasmic membrane. Many of these proteins play an important role in conferring resistance to toxic compounds. The multidrug efflux systems encountered in prokaryotic cells are very similar to those observed in eukaryotic cells. Therefore, a

  16. Bioluminescent hydrocarbonclastic bacteria of the Niger Delta ...

    African Journals Online (AJOL)

    Utilization of three petroleum hydrocarbons (Mobil SAE 40 Engine Oil, Diesel and Bonny light Crude Oil) by four bioluminescent bacteria (Vibrio harveyi, V. fisheri, Photobacterium leiognathi and P. Phosphoreum isolated from the Bonny estuary in the Niger Delta, Nigeria was investigated. Microbial utilization was monitored ...

  17. Pathomorphology and aerobic bacteria associated with pneumonia ...

    African Journals Online (AJOL)

    Pneumonia occurs in all ages of sheep and goats, in all breeds, in every country of the world causing heavy economic losses. The aim of this study was to determine the prevalence of pneumonia and aerobic bacteria flora associated with it in small ruminants slaughtered at the Nsukka abattoir. Pneumonic lung of small ...

  18. Metabolic plasticity for isoprenoid biosynthesis in bacteria.

    Science.gov (United States)

    Pérez-Gil, Jordi; Rodríguez-Concepción, Manuel

    2013-05-15

    Isoprenoids are a large family of compounds synthesized by all free-living organisms. In most bacteria, the common precursors of all isoprenoids are produced by the MEP (methylerythritol 4-phosphate) pathway. The MEP pathway is absent from archaea, fungi and animals (including humans), which synthesize their isoprenoid precursors using the completely unrelated MVA (mevalonate) pathway. Because the MEP pathway is essential in most bacterial pathogens (as well as in the malaria parasites), it has been proposed as a promising new target for the development of novel anti-infective agents. However, bacteria show a remarkable plasticity for isoprenoid biosynthesis that should be taken into account when targeting this metabolic pathway for the development of new antibiotics. For example, a few bacteria use the MVA pathway instead of the MEP pathway, whereas others possess the two full pathways, and some parasitic strains lack both the MVA and the MEP pathways (probably because they obtain their isoprenoids from host cells). Moreover, alternative enzymes and metabolic intermediates to those of the canonical MVA or MEP pathways exist in some organisms. Recent work has also shown that resistance to a block of the first steps of the MEP pathway can easily be developed because several enzymes unrelated to isoprenoid biosynthesis can produce pathway intermediates upon spontaneous mutations. In the present review, we discuss the major advances in our knowledge of the biochemical toolbox exploited by bacteria to synthesize the universal precursors for their essential isoprenoids.

  19. Chitinolytic bacteria of the mammal digestive tract

    Czech Academy of Sciences Publication Activity Database

    Šimůnek, Jiří; Hodrová, Blanka; Bartoňová, H.; Kopečný, Jan

    2001-01-01

    Roč. 46, č. 1 (2001), s. 76-78 ISSN 0015-5632 R&D Projects: GA ČR GA525/00/0984; GA AV ČR KSK5052113 Keywords : chitinolytic bacteria Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 0.776, year: 2001

  20. Tolerance of anaerobic bacteria to chlorinated solvents.

    Science.gov (United States)

    Koenig, Joanna C; Groissmeier, Kathrin D; Manefield, Mike J

    2014-01-01

    The aim of this research was to evaluate the effects of four chlorinated aliphatic hydrocarbons (CAHs), perchloroethene (PCE), carbon tetrachloride (CT), chloroform (CF) and 1,2-dichloroethane (1,2-DCA), on the growth of eight anaerobic bacteria: four fermentative species (Escherichia coli, Klebsiella sp., Clostridium sp. and Paenibacillus sp.) and four respiring species (Pseudomonas aeruginosa, Geobacter sulfurreducens, Shewanella oneidensis and Desulfovibrio vulgaris). Effective concentrations of solvents which inhibited growth rates by 50% (EC50) were determined. The octanol-water partition coefficient or log Po/w of a CAH proved a generally satisfactory measure of its toxicity. Most species tolerated approximately 3-fold and 10-fold higher concentrations of the two relatively more polar CAHs CF and 1,2-DCA, respectively, than the two relatively less polar compounds PCE and CT. EC50 values correlated well with growth rates observed in solvent-free cultures, with fast-growing organisms displaying higher tolerance levels. Overall, fermentative bacteria were more tolerant to CAHs than respiring species, with iron- and sulfate-reducing bacteria in particular appearing highly sensitive to CAHs. These data extend the current understanding of the impact of CAHs on a range of anaerobic bacteria, which will benefit the field of bioremediation.

  1. The proteolytic systems of lactic acid bacteria

    NARCIS (Netherlands)

    Kunji, Edmund R.S.; Mierau, Igor; Hagting, Anja; Poolman, Bert; Konings, Wil N.

    1996-01-01

    Proteolysis in dairy lactic acid bacteria has been studied in great detail by genetic, biochemical and ultrastructural methods. From these studies the picture emerges that the proteolytic systems of lactococci and lactobacilli are remarkably similar in their components and mode of action. The

  2. Proteolytic enzymes of lactic acid bacteria

    NARCIS (Netherlands)

    Law, J; Haandrikman, A

    The proteolytic system of lactic acid bacteria is essential for their growth in milk and contributes significantly to flavour development in fermented milk products where these microorganisms are used as starter cultures. The proteolytic system is composed of proteinases which initially cleave the

  3. Biological Potential of Chitinolytic Marine Bacteria

    DEFF Research Database (Denmark)

    Paulsen, Sara Skøtt; Andersen, Birgitte; Gram, Lone

    2016-01-01

    Chitinolytic microorganisms secrete a range of chitin modifying enzymes, which can be exploited for production of chitin derived products or as fungal or pest control agents. Here, we explored the potential of 11 marine bacteria (Pseudoalteromonadaceae, Vibrionaceae) for chitin degradation using...

  4. Exopolysaccharides produced by lactic acid bacteria

    NARCIS (Netherlands)

    Caggianiello, Graziano; Kleerebezem, Michiel; Spano, Giuseppe

    2016-01-01

    A wide range of lactic acid bacteria (LAB) is able to produce capsular or extracellular polysaccharides, with various chemical compositions and properties. Polysaccharides produced by LAB alter the rheological properties of the matrix in which they are dispersed, leading to typically viscous and

  5. Radiographic markers - A reservoir for bacteria?

    International Nuclear Information System (INIS)

    Tugwell, Jenna; Maddison, Adele

    2011-01-01

    Introduction: Amongst the most frequently handled objects in the radiology department are radiographic markers. They are personal accessories used with every patient, and are kept in the radiographers pockets when not utilised. Upon enquiry it was discovered that many radiographers disregarded the potential of these accessories to become a vector for cross-contamination thus never or rarely clean them. The aims of this study were therefore to identify if radiographic markers are a reservoir for bacteria and to establish an effective cleaning method for decontaminating them. Methodology: 25 radiographers/student radiographers were selected for this study. Swabbing of their markers prior and post cleaning took place. The microbiology laboratory subsequently analyzed the results by quantifying and identifying the bacteria present. The participants also completed a closed questionnaire regarding their markers (e.g. frequency of cleaning and type of marker) to help specify the results gained from the swabbing procedure. Results: From the sample swabbed, 92% were contaminated with various organisms including Staphylococcus and Bacillus species, the amount of bacteria present ranged from 0 to >50 CFU. There were no significant differences between disinfectant wipes and alcohol gel in decontaminating the markers. Both successfully reduced their bacterial load, with 80% of the markers post cleaning having 0 CFU. Conclusion: The results indicated that radiographic markers can become highly contaminated with various organisms thus serve as a reservoir for bacteria. In addition, the markers need to be cleaned on a regular basis, with either disinfectant wipes or alcohol gel to reduce their bacterial load.

  6. Heterotrophic bacteria associated with the green alga

    NARCIS (Netherlands)

    Ismail, A.; Ktari, L.; Ahmed, M.; Bolhuis, H.; Bouhaouala-Zahar, B.; Stal, L.J.; Boudabbous, A.; El Bour, M.

    2018-01-01

    Heterotrophic bacteria associated with the green alga Ulva rigida, collected from the coast of Tunisia, were isolated andsubsequently identified by their 16S rRNA gene sequences and by phylogenetic analysis. The 71 isolates belong to four phyla:Proteobacteria (Alpha-and Gamma- subclasses),

  7. Study Strategies

    DEFF Research Database (Denmark)

    Nielsen, Camilla Kirketerp; Noer, Vibeke Røn

    and theory forms the basis of the research. Veterinary students have been followed through alternating learning contexts referring to both the scholastic academic classrooms and workplaces in commercial pig herds as well as to group work and game-based situations in a mandatory master course - ”the pig...... as a student´ and the process of professionalization. By maintaining the position of focusing upon the education as a situated and formative trajectory, the comparative analysis shows how students in profession-oriented educational settings manage the challenges of education and use study strategies......ID: 1277 / 22 SES 06 B: 2 22. Research in Higher Education Format of Presentation: Paper Alternative EERA Network: 19. Ethnography Topics: NW 22: Teaching, learning and assessment in higher education Keywords: Profession-oriented learning, study strategies, professionalisation processes...

  8. Arbitrage strategy

    OpenAIRE

    Kardaras, Constantinos

    2010-01-01

    An arbitrage strategy allows a financial agent to make certain profit out of nothing, i.e., out of zero initial investment. This has to be disallowed on economic basis if the market is in equilibrium state, as opportunities for riskless profit would result in an instantaneous movement of prices of certain financial instruments. The principle of not allowing for arbitrage opportunities in financial markets has far-reaching consequences, most notably the option-pricing and hedging formulas in c...

  9. Marketing Strategy

    OpenAIRE

    Andrýsková, Hana

    2013-01-01

    The aim of this thesis is to examine current marketing efforts of AARON - the leading seller of digital cameras. I will analyze current marketing tools and suggest improvements in efficiency and effectiveness of these tools. Marketing strategy is a method of managing and coordinating efforts in marketing field so that the goals can be reached. The aim is to increase sales, turnover, revenues, profits, drive out competition and also to build up a corporate image and corporate culture. I will a...

  10. The interaction of bacteria and metal surfaces

    International Nuclear Information System (INIS)

    Mansfeld, Florian

    2007-01-01

    This review discusses different examples for the interaction of bacteria and metal surfaces based on work reported previously by various authors and work performed by the author with colleagues at other institutions and with his graduate students at CEEL. Traditionally it has been assumed that the interaction of bacteria with metal surfaces always causes increased corrosion rates ('microbiologically influenced corrosion' (MIC)). However, more recently it has been observed that many bacteria can reduce corrosion rates of different metals and alloys in many corrosive environments. For example, it has been found that certain strains of Shewanella can prevent pitting of Al 2024 in artificial seawater, tarnishing of brass and rusting of mild steel. It has been observed that corrosion started again when the biofilm was killed by adding antibiotics. The mechanism of corrosion protection seems to be different for different bacteria since it has been found that the corrosion potential E corr became more negative in the presence of Shewanella ana and algae, but more positive in the presence of Bacillus subtilis. These findings have been used in an initial study of the bacterial battery in which Shewanella oneidensis MR-1 was added to a cell containing Al 2024 and Cu in a growth medium. It was found that the power output of this cell continuously increased with time. In the microbial fuel cell (MFC) bacteria oxidize the fuel and transfer electrons directly to the anode. In initial studies EIS has been used to characterize the anode, cathode and membrane properties for different operating conditions of a MFC that contained Shewanella oneidensis MR-1. Cell voltage (V)-current density (i) curves were obtained using potentiodynamic sweeps. The current output of a MFC has been monitored for different experimental conditions

  11. The interaction of bacteria and metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Mansfeld, Florian [Corrosion and Environmental Effects Laboratory (CEEL), The Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-0241 (United States)

    2007-10-10

    This review discusses different examples for the interaction of bacteria and metal surfaces based on work reported previously by various authors and work performed by the author with colleagues at other institutions and with his graduate students at CEEL. Traditionally it has been assumed that the interaction of bacteria with metal surfaces always causes increased corrosion rates ('microbiologically influenced corrosion' (MIC)). However, more recently it has been observed that many bacteria can reduce corrosion rates of different metals and alloys in many corrosive environments. For example, it has been found that certain strains of Shewanella can prevent pitting of Al 2024 in artificial seawater, tarnishing of brass and rusting of mild steel. It has been observed that corrosion started again when the biofilm was killed by adding antibiotics. The mechanism of corrosion protection seems to be different for different bacteria since it has been found that the corrosion potential E{sub corr} became more negative in the presence of Shewanella ana and algae, but more positive in the presence of Bacillus subtilis. These findings have been used in an initial study of the bacterial battery in which Shewanella oneidensis MR-1 was added to a cell containing Al 2024 and Cu in a growth medium. It was found that the power output of this cell continuously increased with time. In the microbial fuel cell (MFC) bacteria oxidize the fuel and transfer electrons directly to the anode. In initial studies EIS has been used to characterize the anode, cathode and membrane properties for different operating conditions of a MFC that contained Shewanella oneidensis MR-1. Cell voltage (V) - current density (i) curves were obtained using potentiodynamic sweeps. The current output of a MFC has been monitored for different experimental conditions. (author)

  12. [Methanotrophic bacteria of acid sphagnum bogs].

    Science.gov (United States)

    Dedysh, S N

    2002-01-01

    Acid sphagnum bogs cover a considerable part of the territory of Russia and are an important natural source of biogenic methane, which is formed in their anaerobic layers. A considerable portion of this methane is consumed in the aerobic part of the bog profile by acidophilic methanotrophic bacteria, which comprise the methane filter of sphagnum bogs and decrease CH4 emission to the atmosphere. For a long time, these bacteria escaped isolation, which became possible only after the elucidation of the optimal conditions of their functioning in situ: pH 4.5 to 5.5; temperature, from 15 to 20 degrees C; and low salt concentration in the solution. Reproduction of these conditions and rejection of earlier used media with a high content of biogenic elements allowed methanotrophic bacteria of two new genera and species--Methylocella palustris and Methylocapsa acidophila--to be isolated from the peat of sphagnum bogs of the northern part of European Russia and West Siberia. These bacteria are well adapted to the conditions in cold, acid, oligotrophic sphagnum bogs. They grow in a pH range of 4.2-7.5 with an optimum at 5.0-5.5, prefer moderate temperatures (15-25 degrees C) and media with a low content of mineral salts (200-500 mg/l), and are capable of active nitrogen fixation. Design of fluorescently labeled 16S rRNA-targeted oligonucleotide probes for the detection of Methylocella palustris and Methylocapsa acidophila and their application to the analysis of sphagnum peat samples showed that these bacteria represent dominant populations of methanotrophs with a density of 10(5)-10(6) cells/g peat. In addition to Methylocella and Methylocapsa populations, one more abundant population of methanotrophs was revealed (10(6) cells/g peat), which were phylogenetically close to the genus Methylocystis.

  13. Anaerobic bacteria in wastewater treatment plant.

    Science.gov (United States)

    Cyprowski, Marcin; Stobnicka-Kupiec, Agata; Ławniczek-Wałczyk, Anna; Bakal-Kijek, Aleksandra; Gołofit-Szymczak, Małgorzata; Górny, Rafał L

    2018-03-28

    The objective of this study was to assess exposure to anaerobic bacteria released into air from sewage and sludge at workplaces from a wastewater treatment plant (WWTP). Samples of both sewage and sludge were collected at six sampling points and bioaerosol samples were additionally collected (with the use of a 6-stage Andersen impactor) at ten workplaces covering different stages of the technological process. Qualitative identification of all isolated strains was performed using the biochemical API 20A test. Additionally, the determination of Clostridium pathogens was carried out using 16S rRNA gene sequence analysis. The average concentration of anaerobic bacteria in the sewage samples was 5.49 × 10 4 CFU/mL (GSD = 85.4) and in sludge-1.42 × 10 6 CFU/g (GSD = 5.1). In turn, the average airborne bacterial concentration was at the level of 50 CFU/m 3 (GSD = 5.83) and the highest bacterial contamination (4.06 × 10 3  CFU/m 3 ) was found in winter at the bar screens. In total, 16 bacterial species were determined, from which the predominant strains belonged to Actinomyces, Bifidobacterium, Clostridium, Propionibacterium and Peptostreptococcus genera. The analysis revealed that mechanical treatment processes were responsible for a substantial emission of anaerobic bacteria into the air. In both the sewage and air samples, Clostridium perfringens pathogen was identified. Anaerobic bacteria were widely present both in the sewage and in the air at workplaces from the WWTP, especially when the technological process was performed in closed spaces. Anaerobic bacteria formed small aggregates with both wastewater droplets and dust particles of sewage sludge origin and as such may be responsible for adverse health outcomes in exposed workers.

  14. The Potential of Indigenous Bacteria for Removing Cadmium from Industrial Wastewater in Lawang, East Java

    OpenAIRE

    Agung Pambudiono; Endang Suarsini; Mohamad Amin

    2018-01-01

    Heavy metals have been used in various areas around the world especially in the industrial sector. Heavy metals contamination is very dangerous for ecosystem because of its toxicity for some organisms. Cadmium (Cd) is a dangerous metal pollutant that can cause remarkable diverse of toxic effects, in particular for humans and animals. The use of bacteria as bioremediation agents has been widely studied because more efficient, less cost, and environmentally friendly strategy. This present study...

  15. Antibacterial activity of silver-killed bacteria: the "zombies" effect

    Science.gov (United States)

    Wakshlak, Racheli Ben-Knaz; Pedahzur, Rami; Avnir, David

    2015-04-01

    We report a previously unrecognized mechanism for the prolonged action of biocidal agents, which we denote as the zombies effect: biocidally-killed bacteria are capable of killing living bacteria. The concept is demonstrated by first killing Pseudomonas aeruginosa PAO1 with silver nitrate and then challenging, with the dead bacteria, a viable culture of the same bacterium: Efficient antibacterial activity of the killed bacteria is observed. A mechanism is suggested in terms of the action of the dead bacteria as a reservoir of silver, which, due to Le-Chatelier's principle, is re-targeted to the living bacteria. Langmuirian behavior, as well as deviations from it, support the proposed mechanism.

  16. Estratégias de cultivo para produção dos plásticos biodegradáveis poli(3-Hidroxibutirato e poli(3-hidroxibutirato-co-3-hidroxivalerato por bactérias Cultivation strategies for production of the biodegradable plastics poly(3-hydroxybutyrate and poly(3-hydroxybutyrate-co-3-hydroxyvalerate by bacteria

    Directory of Open Access Journals (Sweden)

    Cláudia Regina Squio

    2004-08-01

    Full Text Available Polyhydroxyalkanoates (PHAs are carbon and energy storage materials that are accumulated as intracellular granules in a variety of microorganisms during unbalanced growth. PHAs have drawn attention due to their properties similar to conventional plastics and complete biodegradability. They can be used for food and cosmetics packaging, and in medicine and agriculture. However, their applicability is reduced because of their high production cost compared to conventional plastics. An overview on production strategies of poly(3-hydroxybutyrate and poly(3-hydroxybutyrate-co-3-hydroxyvalerate aiming at reducing the production costs is presented.

  17. Strategies for combating bacterial biofilm infections

    DEFF Research Database (Denmark)

    Wu, Hong; Moser, Claus Ernst; Wang, Heng-Zhuang

    2015-01-01

    Formation of biofilm is a survival strategy for bacteria and fungi to adapt to their living environment, especially in the hostile environment. Under the protection of biofilm, microbial cells in biofilm become tolerant and resistant to antibiotics and the immune responses, which increases the di.......International Journal of Oral Science advance online publication, 12 December 2014; doi:10.1038/ijos.2014.65....

  18. Characteristic sizes of life in the oceans - from bacteria to whales

    DEFF Research Database (Denmark)

    Andersen, Ken Haste; Berge, T.; Goncalves, R.

    2016-01-01

    -based scaling laws for resource acquisition, mobility, sensory range, and progeny size for all pelagic marine life, from bacteria to whales. Further, we review and develop simple theoretical arguments for observed scaling laws and the characteristic sizes of a change or breakdown of power laws. We divide life...... in the ocean into seven major realms based on trophic strategy, physiology, and life history strategy. Such a categorization represents a move away from a taxonomically oriented description toward a trait-based description of life in the oceans. Finally, we discuss life forms that transgress the simple size......-based rules and identify unanswered questions....

  19. Impact of Matric Potential and Pore Size Distribution on Growth Dynamics of Filamentous and Non-Filamentous Soil Bacteria

    NARCIS (Netherlands)

    Wolf, A.B.; Vos, de M.; Boer, de W.; Kowalchuk, G.A.

    2013-01-01

    The filamentous growth form is an important strategy for soil microbes to bridge air-filled pores in unsaturated soils. In particular, fungi perform better than bacteria in soils during drought, a property that has been ascribed to the hyphal growth form of fungi. However, it is unknown if, and to

  20. Influence of natural substrates and co-occurring marine bacteria on the production of secondary metabolites by Photobacterium halotolerans

    DEFF Research Database (Denmark)

    Månsson, Maria; Giobergia, Sonia; Møller, Kirsten A.

    Genome sequences reveal that our current standard laboratory conditions only support a fraction of the potential secondary metabolism in bacteria. Thus, we must rethink cultivation, detection, and isolation strategies for bacterial secondary metabolites in order to explore the huge, so far...

  1. Impact of matric potential and pore size distribution on growth dynamics of filamentous and non-filamentous soil bacteria

    NARCIS (Netherlands)

    Wolf, A.B.; Vos, M.; De Boer, W.; Kowalchuk, G.A.

    2013-01-01

    The filamentous growth form is an important strategy for soil microbes to bridge air-filled pores in unsaturated soils. In particular, fungi perform better than bacteria in soils during drought, a property that has been ascribed to the hyphal growth form of fungi. However, it is unknown if, and to

  2. Consumer Exposure to Antimicrobial Resistant Bacteria From Food at Swiss Retail Level

    Directory of Open Access Journals (Sweden)

    Christoph Jans

    2018-03-01

    products featured a medium to high potential of AMR exposure for Gram-negative and Gram-positive foodborne pathogens and indicator bacteria. Food at retail, additional food categories including fermented and novel foods as well as technologically important bacteria and AMR genetics are recommended to be better integrated into systematic One Health AMR surveillance and mitigation strategies to close observed knowledge gaps and enable a comprehensive AMR risk assessment for consumers.

  3. Consumer Exposure to Antimicrobial Resistant Bacteria From Food at Swiss Retail Level

    Science.gov (United States)

    Jans, Christoph; Sarno, Eleonora; Collineau, Lucie; Meile, Leo; Stärk, Katharina D. C.; Stephan, Roger

    2018-01-01

    featured a medium to high potential of AMR exposure for Gram-negative and Gram-positive foodborne pathogens and indicator bacteria. Food at retail, additional food categories including fermented and novel foods as well as technologically important bacteria and AMR genetics are recommended to be better integrated into systematic One Health AMR surveillance and mitigation strategies to close observed knowledge gaps and enable a comprehensive AMR risk assessment for consumers. PMID:29559960

  4. Transfusion strategy

    DEFF Research Database (Denmark)

    Jakobsen, Carl-Johan

    2014-01-01

    Blood transfusion is associated with increased morbidity and mortality and numerous reports have emphasised the need for reduction. Following this there is increased attention to the concept of patient blood management. However, bleeding is relatively common following cardiac surgery and is furth....... In conclusion the evidence supports that each institution establishes its own patient blood management strategy to both conserve blood products and maximise outcome.......Blood transfusion is associated with increased morbidity and mortality and numerous reports have emphasised the need for reduction. Following this there is increased attention to the concept of patient blood management. However, bleeding is relatively common following cardiac surgery and is further...

  5. Production of L-carnitine by secondary metabolism of bacteria

    Directory of Open Access Journals (Sweden)

    Iborra José L

    2007-10-01

    Full Text Available Abstract The increasing commercial demand for L-carnitine has led to a multiplication of efforts to improve its production with bacteria. The use of different cell environments, such as growing, resting, permeabilized, dried, osmotically stressed, freely suspended and immobilized cells, to maintain enzymes sufficiently active for L-carnitine production is discussed in the text. The different cell states of enterobacteria, such as Escherichia coli and Proteus sp., which can be used to produce L-carnitine from crotonobetaine or D-carnitine as substrate, are analyzed. Moreover, the combined application of both bioprocess and metabolic engineering has allowed a deeper understanding of the main factors controlling the production process, such as energy depletion and the alteration of the acetyl-CoA/CoA ratio which are coupled to the end of the biotransformation. Furthermore, the profiles of key central metabolic activities such as the TCA cycle, the glyoxylate shunt and the acetate metabolism are seen to be closely interrelated and affect the biotransformation efficiency. Although genetically modified strains have been obtained, new strain improvement strategies are still needed, especially in Escherichia coli as a model organism for molecular biology studies. This review aims to summarize and update the state of the art in L-carnitine production using E. coli and Proteus sp, emphasizing the importance of proper reactor design and operation strategies, together with metabolic engineering aspects and the need for feed-back between wet and in silico work to optimize this biotransformation.

  6. Walleye Autochthonous Bacteria as Promising Probiotic Candidates against Flavobacterium columnare

    Directory of Open Access Journals (Sweden)

    Hamza Seghouani

    2017-07-01

    Full Text Available Walleye (Sander vitreus is the second most fished freshwater species in Canada. While much sought by anglers, walleye also supports substantial commercial fisheries. To cope with the recent decline of wild walleye populations, fish farmers produce juveniles for lake stocking. However, walleye breeding is particularly tedious, mostly due to high disease susceptibility at larval and juvenile developmental stages. The main threat is the columnaris disease, which is caused by Flavobacterium columnare, an opportunistic bacteria. As F. columnare strains exhibit increasing antibiotic resistance, there is a strong need to develop efficient and sustainable alternative strategies to control columnaris disease. Bacterial probiotics have been shown to mitigate infections either by enhancing host immune response or by inhibiting pathogen growth. Being successfully assessed in many fish/pathogen combinations, we developed a tailored probiotic strategy for walleye to prevent and treat columnaris disease. Thirty-seven endogenous bacterial strains were isolated from healthy walleye’s skin and gut, were tested in vitro against F. columnare. Significant antagonistic effect against F. columnare was measured for 2 out of 37 endogenous strains. These two probiotic strains were identified as Pseudomonas fluorescens. The antagonistic effect of these two successful probiotics was further validated in vivo during a 2-month stress trial: groups receiving probiotic treatments showed on average 53.74% survival improvement.

  7. Antibiotic resistance in bacteria associated with food animals: a United States perspective of livestock production.

    Science.gov (United States)

    Mathew, Alan G; Cissell, Robin; Liamthong, S

    2007-01-01

    The use of antimicrobial compounds in food animal production provides demonstrated benefits, including improved animal health, higher production and, in some cases, reduction in foodborne pathogens. However, use of antibiotics for agricultural purposes, particularly for growth enhancement, has come under much scrutiny, as it has been shown to contribute to the increased prevalence of antibiotic-resistant bacteria of human significance. The transfer of antibiotic resistance genes and selection for resistant bacteria can occur through a variety of mechanisms, which may not always be linked to specific antibiotic use. Prevalence data may provide some perspective on occurrence and changes in resistance over time; however, the reasons are diverse and complex. Much consideration has been given this issue on both domestic and international fronts, and various countries have enacted or are considering tighter restrictions or bans on some types of antibiotic use in food animal production. In some cases, banning the use of growth-promoting antibiotics appears to have resulted in decreases in prevalence of some drug resistant bacteria; however, subsequent increases in animal morbidity and mortality, particularly in young animals, have sometimes resulted in higher use of therapeutic antibiotics, which often come from drug families of greater relevance to human medicine. While it is clear that use of antibiotics can over time result in significant pools of resistance genes among bacteria, including human pathogens, the risk posed to humans by resistant organisms from farms and livestock has not been clearly defined. As livestock producers, animal health experts, the medical community, and government agencies consider effective strategies for control, it is critical that science-based information provide the basis for such considerations, and that the risks, benefits, and feasibility of such strategies are fully considered, so that human and animal health can be maintained while

  8. Interactions between Paramyxoviruses and Bacteria: Implications for Pathogenesis and Intervention

    NARCIS (Netherlands)

    D.T. Nguyen (Tien)

    2014-01-01

    markdownabstract__Abstract__ Globally, respiratory tract diseases caused by bacteria and viruses are an important burden of disease. Respiratory bacteria (Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and Staphylococcus aureus) can colonize the upper respiratory tract.

  9. Time related total lactic acid bacteria population diversity and ...

    African Journals Online (AJOL)

    user

    2011-02-07

    Feb 7, 2011 ... the diversity and dynamics of lactic acid bacteria (LAB) population in fresh ..... combining morphological, biochemical and molecular data are important for ..... acid bacteria from fermented maize (Kenkey) and their interactions.

  10. Oh What a Tangled Biofilm Web Bacteria Weave

    Science.gov (United States)

    ... Home Page Oh What a Tangled Biofilm Web Bacteria Weave By Elia Ben-Ari Posted May 1, ... a suitable surface, some water and nutrients, and bacteria will likely put down stakes and form biofilms. ...

  11. The Effect of Bacteria Penetration on Chalk Permeability

    DEFF Research Database (Denmark)

    Halim, Amalia Yunita; Shapiro, Alexander; Nielsen, Sidsel Marie

    number of B. licheniformis was detected on the effluent compared with P. putida. However, in the experiment with B. licheniformis mainly spores were detected in the effluent. The core permeability decreased rapidly during injection of bacteria and a starvation period of 12 days did not allow......Bacteria selective plugging is one of the mechanisms through which microorganisms can be applied for enhanced oil recovery. Bacteria can plug the water-bearing zones of a reservoir, thus altering the flow paths and improving sweep efficiency. It is known that the bacteria can penetrate deeply...... into reservoirs, however, a complete understanding of the penetration behavior of bacteria is lacking, especially in chalk formations where the pore throat sizes are almost comparable with the sizes of bacteria vegetative cells. This study investigates the penetration of bacteria into chalk. Two bacteria types...

  12. Developing new bacteria subroutines in the SWAT model

    Science.gov (United States)

    Fecal bacteria observations from four different sites in Korea and the US demonstrate seasonal variability, showing a significant relationship with temperature (Figure 1); fecal indicator bacteria (FIB) concentrations are relatively higher in summer and lower in winter , including Stillwater river (...

  13. Bacteria Associated with Fresh Tilapia Fish (Oreochromis niloticus ...

    African Journals Online (AJOL)

    acer

    Keywords: Bacteria, Tilapia fish and Sokoto central market. INTRODUCTION ... The bacteria are transmitted by fish that have made contact ... with which a product spoils is also related to the .... Base on the percentage frequency of occurance ,.

  14. Frequency of Resistance and Susceptible Bacteria Isolated from Houseflies

    Directory of Open Access Journals (Sweden)

    B Davari

    2010-12-01

    Conclusion: Houseflies collected from hospitals and slaughterhouse may be involved in the spread of drug resistant bacteria and may increase the potential of human exposure to drug resistant bacteria.

  15. NATO strategy

    International Nuclear Information System (INIS)

    Tarr, D.W.

    1988-01-01

    Nuclear weapons are for NATO both the primary instrument for deterring a nuclear attack and the fall-back option if, in the event of a conventional assault, NATO's non-nuclear defence forces cannot hold. The dilemma of depending upon potentially self-destructive nuclear responses if deterrence fails and defence falters has always haunted NATO strategy, but after the Soviets achieved nuclear parity with the United States, this dilemma became more intensely perceived. Now the credibility, viability, acceptability, sensibility and morality of nuclear weapons for deterrence and defence are increasingly at issue. As a result, an increasing variety of non-nuclear (conventional) alternatives are being advanced to replace or supplement nuclear deterrence for the Alliance. The thrust of the author of this paper remarks is to attempt to apply the definitions, requirements, and other key conceptual distinctions of nuclear deterrence found in the body of western strategic literature to three categories of non-nuclear alternatives currently in vogue: strengthened conventional forces; deployment of new, high-technology non-nuclear weapons; and adoption of an offensive manoeuvre strategy. Let me, therefore, begin by listing the basic definitions, concepts and apparent requirements of deterrence which the deterrence theory literature offers

  16. Have sex or not? Lessons from bacteria.

    Science.gov (United States)

    Lodé, T

    2012-01-01

    Sex is one of the greatest puzzles in evolutionary biology. A true meiotic process occurs only in eukaryotes, while in bacteria, gene transcription is fragmentary, so asexual reproduction in this case really means clonal reproduction. Sex could stem from a signal that leads to increased reproductive output of all interacting individuals and could be understood as a secondary consequence of primitive metabolic reactions. Meiotic sex evolved in proto-eukaryotes to solve a problem that bacteria did not have, namely a large amount of DNA material, occurring in an archaic step of proto-cell formation and genetic exchanges. Rather than providing selective advantages through reproduction, sex could be thought of as a series of separate events which combines step-by-step some very weak benefits of recombination, meiosis, gametogenesis and syngamy. Copyright © 2012 S. Karger AG, Basel.

  17. 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.

  18. Ancient bacteria show evidence of DNA repair

    DEFF Research Database (Denmark)

    Johnson, Sarah Stewart; Hebsgaard, Martin B; Christensen, Torben R

    2007-01-01

    -term survival of bacteria sealed in frozen conditions for up to one million years. Our results show evidence of bacterial survival in samples up to half a million years in age, making this the oldest independently authenticated DNA to date obtained from viable cells. Additionally, we find strong evidence...... geological timescales. There has been no direct evidence in ancient microbes for the most likely mechanism, active DNA repair, or for the metabolic activity necessary to sustain it. In this paper, we couple PCR and enzymatic treatment of DNA with direct respiration measurements to investigate long...... that this long-term survival is closely tied to cellular metabolic activity and DNA repair that over time proves to be superior to dormancy as a mechanism in sustaining bacteria viability....

  19. Protein-Injection Machines in Bacteria.

    Science.gov (United States)

    Galán, Jorge E; Waksman, Gabriel

    2018-03-08

    Many bacteria have evolved specialized nanomachines with the remarkable ability to inject multiple bacterially encoded effector proteins into eukaryotic or prokaryotic cells. Known as type III, type IV, and type VI secretion systems, these machines play a central role in the pathogenic or symbiotic interactions between multiple bacteria and their eukaryotic hosts, or in the establishment of bacterial communities in a diversity of environments. Here we focus on recent progress elucidating the structure and assembly pathways of these machines. As many of the interactions shaped by these machines are of medical importance, they provide an opportunity to develop novel therapeutic approaches to combat important human diseases. Copyright © 2018 Elsevier Inc. All rights reserved.

  20. Seeing Streptococcus pneumoniae, a Common Killer Bacteria

    DEFF Research Database (Denmark)

    Kjærgaard, Rikke Schmidt; Andersen, Ebbe Sloth

    2014-01-01

    Look around you. The diversity and complexity of life on earth is overwhelming and data continues to grow. In our desire to understand and explain everything scientifically from molecular evolution to supernovas we depend on visual representations. This paper investigates visual representations...... of the bacteria Streptococcus pneumoniae by use of ink, watercolours and computer graphics. We propose a novel artistic visual rendering of Streptococcus pneumoniae and ask what the value of these kind of representations are compared to traditional scientific data. We ask if drawings and computer......-assisted representations can add to our scientific knowledge about this dangerous bacteria. Is there still a role for the scientific illustrator in the scientific process and synthesis of scientific knowledge?...

  1. [Synthesis of reserve polyhydroxyalkanoates by luminescent bacteria].

    Science.gov (United States)

    Boiandin, A N; Kalacheva, G S; Rodicheva, E K; Volova, T G

    2008-01-01

    The ability of marine luminescent bacteria to synthesize polyesters of hydroxycarboxylic acids (polyhydroxyalkanoates, PHA) as reserve macromolecules was studied. Twenty strains from the collection of the luminescent bacteria CCIBSO (WDSM839) of the Institute of Biophysics, Siberian Branch, Russian Academy of Sciences, assigned to different taxa (Photobacterium leiognathi, Ph. phosphoreum, Vibrio harveyi, and V. fischeri) were analyzed. The most productive strains were identified, and the conditions ensuring high polymer yields in batch culture (40-70% of the cell dry mass weight) were determined. The capacity of synthesizing two- and three-component polymers containing hydroxybutyric acid as the main monomer and hydroxyvaleric and hydroxyhexanoic acids was revealed in Ph. leiognathi and V. harveyi strains. The results allow luminescent microorganisms to be regarded as new producers of multicomponent polyhydroxyalkanoates.

  2. New Insight on the Response of Bacteria to Fluoride

    OpenAIRE

    Breaker, R.R.

    2012-01-01

    Fluoride has been used for decades to prevent caries and it is well established that this anion can inhibit the growth of bacteria. However, the precise effects that fluoride has on bacteria and the mechanisms that bacteria use to overcome fluoride toxicity have largely remained unexplored. Recently, my laboratory reported the discovery of biological systems that bacteria use to sense fluoride and reduce fluoride toxicity. These sensors and their associated genes are very widespread in biolog...

  3. Antioxidant and Antimicrobial Potential of the Bifurcaria bifurcata Epiphytic Bacteria

    OpenAIRE

    Horta, André; Pinteus, Susete; Alves, Celso; Fino, Nádia; Silva, Joana; Fernandez, Sara; Rodrigues, Américo; Pedrosa, Rui

    2014-01-01

    This article belongs to the Special Issue Selected Papers from the 14th International Symposium on Marine Natural Products Surface-associated marine bacteria are an interesting source of new secondary metabolites. The aim of this study was the isolation and identification of epiphytic bacteria from the marine brown alga, Bifurcaria bifurcata, and the evaluation of the antioxidant and antimicrobial activity of bacteria extracts. The identification of epiphytic bacteria was determined by 16S...

  4. Bactericidal effects of antibiotics on slowly growing and nongrowing bacteria.

    OpenAIRE

    Eng, R H; Padberg, F T; Smith, S M; Tan, E N; Cherubin, C E

    1991-01-01

    Antimicrobial agents are most often tested against bacteria in the log phase of multiplication to produce the maximum bactericidal effect. In an infection, bacteria may multiply less optimally. We examined the effects of several classes of antimicrobial agents to determine their actions on gram-positive and gram-negative bacteria during nongrowing and slowly growing phases. Only ciprofloxacin and ofloxacin exhibited bactericidal activity against nongrowing gram-negative bacteria, and no antib...

  5. [Application of anaerobic bacteria detection in oral and maxillofacial infection].

    Science.gov (United States)

    Bao, Zhen-ying; Lin, Qin; Meng, Yan-hong; He, Chun; Su, Jia-zeng; Peng, Xin

    2016-02-18

    To investigate the distribution and drug resistance of anaerobic bacteria in the patients with oral and maxillofacial infection. Aerobic and anaerobic bacteria cultures from 61 specimens of pus from the patients with oral and maxillofacial infection in the Department of Oral and Maxillofacial Surgery, Peking University School of Stomatology were identified. The culture type was evaluated by API 20A kit and drug resistance test was performed by Etest method. The clinical data and antibacterial agents for the treatment of the 61 cases were collected, and the final outcomes were recorded. The bacteria cultures were isolated from all the specimens, with aerobic bacteria only in 6 cases (9.8%), anaerobic bacteria only in 7 cases (11.5%), and both aerobic and anaerobic bacteria in 48 cases (78.7%). There were 55 infected cases (90.2%) with anaerobic bacteria, and 81 anaerobic bacteria stains were isolated. The highest bacteria isolation rate of Gram positive anaerobic bacteria could be found in Peptostreptococcus, Bifidobacterium and Pemphigus propionibacterium. No cefoxitin, amoxicillin/carat acid resistant strain was detected in the above three Gram positive anaerobic bacteria. The highest bacteria isolation rate of Gram negative anaerobic bacteria could be detected in Porphyromonas and Prevotella. No metronidazole, cefoxitin, amoxicillin/carat acid resistant strain was found in the two Gram negative anaerobic bacteria. In the study, 48 patients with oral and maxillofacial infection were treated according to the results of drug resistance testing, and the clinical cure rate was 81.3%. Mixed aerobic and anaerobic bacteria cultures are very common in most oral and maxillofacial infection patients. Anaerobic bacteria culture and drug resistance testing play an important role in clinical treatment.

  6. Cellulase Production by Bacteria: A Review

    OpenAIRE

    Sadhu Sangrila; Maiti Tushar Kanti

    2013-01-01

    Cellulose is an abundant natural biopolymer on earth and most dominating Agricultural waste. This cellulosic biomass is a renewable and abundant resource with great potential for bioconversion to value-added bioproducts. It can be degraded by cellulase produced by cellulolytic bacteria. This enzyme has various industrial applications and now considered as major group of industrial enzyme. The review discusses application of cellulase, classification of cellulase, quantification...

  7. Chemotactic waves of bacteria at the mesoscale

    OpenAIRE

    Calvez, Vincent

    2016-01-01

    The existence of travelling waves for a model of concentration waves of bacteria is investigated. The model consists in a kinetic equation for the biased motion of cells following a run-and-tumble process, coupled with two reaction-diffusion equations for the chemical signals. Strong mathematical difficulties arise in comparison with the diffusive regime which was studied in a previous work. The cornerstone of the proof consists in establishing monotonicity properties of the spatial density o...

  8. Transfer of DNA from Bacteria to Eukaryotes

    Directory of Open Access Journals (Sweden)

    Benoît Lacroix

    2016-07-01

    Full Text Available Historically, the members of the Agrobacterium genus have been considered the only bacterial species naturally able to transfer and integrate DNA into the genomes of their eukaryotic hosts. Yet, increasing evidence suggests that this ability to genetically transform eukaryotic host cells might be more widespread in the bacterial world. Indeed, analyses of accumulating genomic data reveal cases of horizontal gene transfer from bacteria to eukaryotes and suggest that it represents a significant force in adaptive evolution of eukaryotic species. Specifically, recent reports indicate that bacteria other than Agrobacterium, such as Bartonella henselae (a zoonotic pathogen, Rhizobium etli (a plant-symbiotic bacterium related to Agrobacterium, or even Escherichia coli, have the ability to genetically transform their host cells under laboratory conditions. This DNA transfer relies on type IV secretion systems (T4SSs, the molecular machines that transport macromolecules during conjugative plasmid transfer and also during transport of proteins and/or DNA to the eukaryotic recipient cells. In this review article, we explore the extent of possible transfer of genetic information from bacteria to eukaryotic cells as well as the evolutionary implications and potential applications of this transfer.

  9. Intracellular bacteria: the origin of dinoflagellate toxicity.

    Science.gov (United States)

    Silva, E S

    1990-01-01

    Dinoflagellate blooms of the same species have been registered either as toxic or nontoxic and, in the latter case, toxicity may be of different types. A hypothesis has been formulated according to which the bacteria having in some way taken part in the toxin formation are either inside the dinoflagellate cell or in the nutritive liquid. The presence of intracellular bacteria in those microorganisms has been studied mainly in material from cultures, a few from the sea, and several strains were isolated from different species. Experiments with crossed inoculations have shown that the bacterial strain from Gonyaulax tamarensis caused the cells of some other species to become toxic. From nontoxic clonal cultures of Prorocentrum balticum, Glenodinium foliaceum, and Gyrodinium instriatum, after inoculation of that bacterial strain, cultures were obtained whose cell extracts showed the same kind of toxicity as G. tamarensis. No toxic action could be found in the extracts of the bacterial cells form the assayed strains. The interference of intracellular bacteria in the metabolism of dinoflagellates must be the main cause of their toxicity.

  10. Acoustic manipulation of bacteria cells suspensions

    Science.gov (United States)

    GutiéRrez-Ramos, Salomé; Hoyos, Mauricio; Aider, Jean Luc; Ruiz, Carlos; Acoustofluidics Team Team; Soft; Bio Group Collaboration

    An acoustic contacless manipulation gives advantages in the exploration of the complex dynamics enviroment that active matter exhibits. Our works reports the control confinement and dispersion of Escherichia coliRP437-pZA3R-YFP suspensions (M9Glu-Ca) via acoustic levitation.The manipulation of the bacteria bath in a parallel plate resonator is achieved using the acoustic radiation force and the secondary radiation force. The primary radiation force generates levitation of the bacteria cells at the nodal plane of the ultrasonic standing wave generated inside the resonator. On the other side, secondary forces leads to the consolidation of stable aggregates. All the experiments were performed in the acoustic trap described, where we excite the emission plate with a continuous sinusoidal signal at a frequency in the order of MHz and a quartz slide as the reflector plate. In a typical experiment we observed that, before the input of the signal, the bacteria cells exhibit their typical run and tumble behavior and after the sound is turned on all of them displace towards the nodal plane, and instantaneously the aggregation begins in this region. CNRS French National Space Studies, CONACYT Mexico.

  11. Fecal indicator bacteria at Havana Bay

    International Nuclear Information System (INIS)

    Lopez Perez, Lisse; Gomez D'Angelo, Yamiris; Beltran Gonzalez, Jesus; Alvarez Valiente, Reinaldo

    2013-01-01

    Aims: Fecal indicator bacteria concentrations were evaluated in Havana Bay. Methods: Concentrations of traditional fecal indicator bacteria were calculated between April 2010 and February 2011, by MPN methods. Concentrations of thermo tolerant coliform (CTT), Escherichia coli, fecal streptococci (EF), intestinal enterococci (ENT) in seawater, and Clostridium perfringens in sediment surface, were determined. Results: CTT and E. coli levels were far above Cuban water quality standard for indirect contact with water, showing the negative influence of sewage and rivers on the bay. The EF and ENT were measured during sewage spills at the discharge site and they were suitable indicators of fecal contamination, but these indicators didn't show the same behavior in other selected sites. This result comes from its well-known inactivation by solar light in tropical zones and the presumable presence of humid acids in the waters of the bay. Conclusion: Fecal indicator bacteria and its statistical relationships reflect recent and chronic fecal contamination at the bay and near shores.

  12. Alkaline phosphatase activity of rumen bacteria.

    Science.gov (United States)

    Cheng, K J; Costerton, J W

    1977-11-01

    Of the 54 strains of rumen bacteria examined for alkaline phosphatase (APase) production, 9 of 33 gram-negative strains and none of 21 gram-positive strains produced the enzyme. The APase of the cells of the three strains of Bacteroides ruminicola that produced significant amounts of the enzyme was located in the periplasmic area of the cell envelope, whereas the enzyme was located in the strains of Selenomonas ruminantium and Succinivibrio dextrinosolvens was associated with the outer membrane. The localization of APase production in the cells of natural populations of rumen bacteria from hay-fed sheep was accomplished by reaction product deposition, and both the proportion of APase-producing bacteria and the location of the enzyme in the cell envelope of the producing cells could be determined. We suggest that this procedure is useful in detecting shifts in the bacterial population and the release of cell-bound APase that accompany feedlot bloat and other sequelae of dietary manipulation in ruminants.

  13. Soil bacteria for remediation of polluted soils

    Energy Technology Data Exchange (ETDEWEB)

    Springael, D; Bastiaens, L; Carpels, M; Mergaey, M; Diels, L

    1996-09-18

    Soil bacteria, specifically adapted to contaminated soils, may be used for the remediation of polluted soils. The Flemish research institute VITO has established a collection of bacteria, which were isolated from contaminated areas. This collection includes microbacteria degrading mineral oils (Pseudomonas sp., Acinetobacter sp. and others), microbacteria degrading polycyclic aromatic hydrocarbons (genera Sphingomonas and Mycobacterium), microbacteria degrading polychlorobiphenyls (genus Ralstonia and strains related to beta-Proteobacteria), and metal resistant bacteria with plasmid borne resistances to Cd, Zn, Ni, Co, Cu, Hg, and Cr. Bench-scale reactors were developed to investigate the industrial feasibility of bioremediation. Batch Stirred Tank Reactors were used to evaluate the efficiency of oil degraders. Soils, contaminated with non-ferrous metals, were treated using a Bacterial Metal Slurry Reactor. It was found that the reduction of the Cd concentration may vary strongly from sample to sample: reduction factors vary from 95 to 50%. Is was shown that Cd contained in metallic sinter and biologically unavailable Cd could not be removed.

  14. Magnesium and manganese content of halophilic bacteria

    International Nuclear Information System (INIS)

    de Medicis, E.; Paquette, J.; Gauthier, J.J.; Shapcott, D.

    1986-01-01

    Magnesium and manganese contents were measured by atomic absorption spectrophotometry in bacteria of several halophilic levels, in Vibrio costicola, a moderately halophilic eubacterium growing in 1 M NaCl, Halobacterium volcanii, a halophilic archaebacterium growing in 2.5 NaCl, Halobacterium cutirubrum, an extremely halophilic archaebacterium growing in 4 M NaCl, and Escherichia coli, a nonhalophilic eubacterium growing in 0.17 M NaCl. Magnesium and manganese contents varied with the growth phase, being maximal at the early log phase. Magnesium and manganese molalities in cell water were shown to increase with the halophilic character of the logarithmically growing bacteria, from 30 mmol of Mg per kg of cell water and 0.37 mmol of Mn per kg of cell water for E. coli to 102 mmol of Mg per kg of cell water and 1.6 mmol of Mn per kg of cell water for H cutirubrum. The intracellular concentrations of manganese were determined independently by a radioactive tracer technique in V. costicola and H. volcanii. The values obtained by 54 Mn loading represented about 70% of the values obtained by atomic absorption. The increase of magnesium and manganese contents associated with the halophilic character of the bacteria suggests that manganese and magnesium play a role in haloadaptation

  15. Fish skin bacteria: Colonial and cellular hydrophobicity.

    Science.gov (United States)

    Sar, N; Rosenberg, E

    1987-05-01

    Bacteria were desorbed from the skin of healthy, fast-swimming fish by several procedures, including brief exposure to sonic oscillation and treatment with nontoxic surface active agents. The surface properties of these bacteria were studied by measuring their adhesion to hexadecane, as well as by a newly developed, simple method for studying the hydrophobicity of bacterial lawns. This method, referred to as the "Direction of Spreading" (DOS) method, consists of recording the direction to which a water drop spreads when introduced at the border between bacterial lawns and other surfaces. Of the 13 fish skin isolates examined, two strains were as hydrophobic as polystyrene by the DOS method. Suspended cells of one of these strains adhered strongly to hexadecane (84%), whereas cells of the other strain adhered poorly (13%). Another strain which was almost as hydrophobic as polystyrene by the DOS method did not adhere to hexadecane at all. Similarly, lawns of three other strains were more hydrophobic than glass by the DOS method, but cell suspensions prepared from these colonies showed little or no adhesion to hexadecane. The high colonial but relatively low cellular hydrophobicity could be due to a hydrophobic slime that is removed during the suspension and washing procedures. The possibility that specific bacteria assist in fish locomotion by changing the surface properties of the fish skin and by producing drag-reducing polymers is discussed.

  16. Engineering bacteria for enhanced polyhydroxyalkanoates (PHA biosynthesis

    Directory of Open Access Journals (Sweden)

    Guo-Qiang Chen

    2017-09-01

    Full Text Available Polyhydroxyalkanoates (PHA have been produced by some bacteria as bioplastics for many years. Yet their commercialization is still on the way. A few issues are related to the difficulty of PHA commercialization: namely, high cost and instabilities on molecular weights (Mw and structures, thus instability on thermo-mechanical properties. The high cost is the result of complicated bioprocessing associated with sterilization, low conversion of carbon substrates to PHA products, and slow growth of microorganisms as well as difficulty of downstream separation. Future engineering on PHA producing microorganisms should be focused on contamination resistant bacteria especially extremophiles, developments of engineering approaches for the extremophiles, increase on carbon substrates to PHA conversion and controlling Mw of PHA. The concept proof studies could still be conducted on E. coli or Pseudomonas spp. that are easily used for molecular manipulations. In this review, we will use E. coli and halophiles as examples to show how to engineer bacteria for enhanced PHA biosynthesis and for increasing PHA competitiveness.

  17. Contaminant bacteria in traditional-packed honey

    Directory of Open Access Journals (Sweden)

    Hening Tjaturina Pramesti

    2007-03-01

    Full Text Available Honey may be contaminated by microorganisms during its harvesting, processing, and packaging. Honey selected for clinical purposes must safe, sterile, and contain antimicrobial activity, so it must be evaluated using laboratory testing. The aim of this descriptive laboratory study was to isolate and identify the bacterial contaminant in the traditional-packed honey dealing with the use of honey for medical purposes. the colony forming units of honey sample cultured on blood agar were counted using Stuart bacterial colony counter. The suspected bacterial colonies were isolated and identified based on cultural morphology characteristics. The isolates of suspected bacterial colonies were stained according to Gram and Klein method and then were examined by the biochemical reaction. The results showed that there were two contaminant bacteria. Gram-positive cocci which were presumptively identified as coagulase-negative Staphylococci and gram-positive rods which were presumptively identified as Bacillus subtilis. In conclusion, the contaminant bacteria were regarded as low pathogen bacteria. The subtilin enzyme of B subtilis may cause an allergic reaction and coagulase-negative Staphylococci, Staphylococcus epidermidis is also an opportunist pathogen. Inevitably, for medical purposes, traditional-packed honey must be well filtered, water content above 18%, and standardized sterilization without loss of an antibacterial activity or change in properties.

  18. Excitons in intact cells of photosynthetic bacteria.

    Science.gov (United States)

    Freiberg, Arvi; Pajusalu, Mihkel; Rätsep, Margus

    2013-09-26

    Live cells and regular crystals seem fundamentally incompatible. Still, effects characteristic to ideal crystals, such as coherent sharing of excitation, have been recently used in many studies to explain the behavior of several photosynthetic complexes, especially the inner workings of the light-harvesting apparatus of the oldest known photosynthetic organisms, the purple bacteria. To this date, there has been no concrete evidence that the same effects are instrumental in real living cells, leaving a possibility that this is an artifact of unnatural study conditions, not a real effect relevant to the biological operation of bacteria. Hereby, we demonstrate survival of collective coherent excitations (excitons) in intact cells of photosynthetic purple bacteria. This is done by using excitation anisotropy spectroscopy for tracking the temperature-dependent evolution of exciton bands in light-harvesting systems of increasing structural complexity. The temperature was gradually raised from 4.5 K to ambient temperature, and the complexity of the systems ranged from detergent-isolated complexes to complete bacterial cells. The results provide conclusive evidence that excitons are indeed one of the key elements contributing to the energetic and dynamic properties of photosynthetic organisms.

  19. NREL Scientists Model Methane-Eating Bacteria | News | NREL

    Science.gov (United States)

    Scientists Model Methane-Eating Bacteria News Release: NREL Scientists Model Methane-Eating Bacteria February 13, 2018 Nature is full of surprises - not to mention solutions. A research team ) recently explored the possibilities provided by the natural world by researching how the bacteria

  20. Quantification and Qualification of Bacteria Trapped in Chewed Gum

    NARCIS (Netherlands)

    Wessel, Stefan W.; van der Mei, Henny C.; Morando, David; Slomp, Anje M.; van de Belt-Gritter, Betsy; Maitra, Amarnath; Busscher, Henk J.

    2015-01-01

    Chewing of gum contributes to the maintenance of oral health. Many oral diseases, including caries and periodontal disease, are caused by bacteria. However, it is unknown whether chewing of gum can remove bacteria from the oral cavity. Here, we hypothesize that chewing of gum can trap bacteria and

  1. Isolation and characterization of feather degrading bacteria from ...

    African Journals Online (AJOL)

    This study is aimed at isolating and characterizing new culturable feather degrading bacteria from soils of the University of Mauritius Farm. Bacteria that were isolated were tested for their capability to grow on feather meal agar (FMA). Proteolytic bacteria were tested for feather degradation and were further identified ...

  2. Bacteria associated with cultures of psathyrella atroumbonata (Pleger)

    African Journals Online (AJOL)

    These bacteria include Bacillus licheniformis, Bacillus subtilis, Leuconostoc mesenteroides, Pseudomonas aeruginosa, Bacillus cereus and Staphylococcus aureus. The average bacteria count was 1.0 x 106 cfu/ml and these bacteria grew within pH range of 5.0 and 9.0. the optimum temperature range of growth lied ...

  3. The growth of bacteria on organic compounds in drinking water

    NARCIS (Netherlands)

    Kooij, van der D.

    1984-01-01

    Growth ("regrowth") of bacteria In drinking water distribution systems results in a deterioration of the water quality. Regrowth of chemoheterotrophic bacteria depends on the presence of organic. compounds that serve as a nutrient source for these bacteria. A batch-culture technique was

  4. Bacteria associated with contamination of ready-to-eat (RTE ...

    African Journals Online (AJOL)

    The bacteria associated with contamination of ready-to-eat (RTE) cooked rice in Lagos, Nigeria were studied using standard microbiological methods. The objective of this study was to investigate the distribution of pathogenic bacteria recovered from RTE cooked rice in Lagos, assess bacteria load in the contaminated RTE ...

  5. Patterns and sources of fecal coliform bacteria in three streams in Virginia, 1999-2000

    Science.gov (United States)

    Hyer, Kenneth; Moyer, Douglas

    2003-01-01

    (maximum observed concentration of 290,000 colonies/100 milliliters (col/100mL) could occur along the entire length of each stream, and that the samples collected at the downstream monitoring station of each stream were generally representative of the entire upstream reach. Seasonal patterns were observed in the base-flow fecal coliform concentrations of all streams; concentrations were typically highest in the summer and lowest in the winter. Fecal coliform concentrations were lowest during periods of base flow (typically 200?2,000 col/100mL) and increased by 3?4 orders of magnitude during storm events (as high as 700,000 col/100mL). Multiple linear regression models were developed to predict fecal coliform concentrations as a function of streamflow and other water-quality parameters. The source tracking technique provided identification of bacteria contributions from diverse sources that included (but were not limited to) humans, cattle, poultry, horses, dogs, cats, geese, ducks, raccoons, and deer. Seasonal patterns were observed in the contributions of cattle and poultry sources. There were relations between the identified sources of fecal coliform bacteria and the land-use practices within each watershed. There were only minor differences in the distribution of bacteria sources between low-flow periods and high-flow periods. A coupled approach that utilized both a large available source library and a smaller, location-specific source library provided the most success in identifying the unknown E. coli isolates. BST data should provide valuable support and guidance for producing more defendable and scientifically rigorous watershed models. Incorporation of these bacteria-source data into watershed management strategies also should result in the selection of more efficient source-reduction scenarios for improving water quality.

  6. Implementation Strategy

    Science.gov (United States)

    1983-01-01

    Meeting the identified needs of Earth science requires approaching EOS as an information system and not simply as one or more satellites with instruments. Six elements of strategy are outlined as follows: implementation of the individual discipline missions as currently planned; use of sustained observational capabilities offered by operational satellites without waiting for the launch of new mission; put first priority on the data system; deploy an Advanced Data Collection and Location System; put a substantial new observing capability in a low Earth orbit in such a way as to provide for sustained measurements; and group instruments to exploit their capabilities for synergism; maximize the scientific utility of the mission; and minimize the costs of implementation where possible.

  7. Biological hydrogen production from biomass by thermophilic bacteria

    International Nuclear Information System (INIS)

    Claassen, P.A.M.; Mars, A.E.; Budde, M.A.W.; Lai, M.; de Vrije, T.; van Niel, E.W.J.

    2006-01-01

    To meet the reduction of the emission of CO 2 imposed by the Kyoto protocol, hydrogen should be produced from renewable primary energy. Besides the indirect production of hydrogen by electrolysis using electricity from renewable resources, such as sunlight, wind and hydropower, hydrogen can be directly produced from biomass. At present, there are two strategies for the production of hydrogen from biomass: the thermochemical technology, such as gasification, and the biotechnological approach using micro-organisms. Biological hydrogen production delivers clean hydrogen with an environmental-friendly technology and is very suitable for the conversion of wet biomass in small-scale applications, thus having a high chance of becoming an economically feasible technology. Many micro-organisms are able to produce hydrogen from mono- and disaccharides, starch and (hemi)cellulose under anaerobic conditions. The anaerobic production of hydrogen is a common phenomenon, occurring during the process of anaerobic digestion. Here, hydrogen producing micro-organisms are in syn-trophy with methanogenic bacteria which consume the hydrogen as soon as it is produced. In this way, hydrogen production remains obscure and methane is the end-product. By uncoupling hydrogen production from methane production, hydrogen becomes available for recovery and exploitation. This study describes the use of extreme thermophilic bacteria, selected because of a higher hydrogen production efficiency as compared to mesophilic bacteria, for the production of hydrogen from renewable resources. As feedstock energy crops like Miscanthus and Sorghum bicolor and waste streams like domestic organic waste, paper sludge and potato steam peels were used. The feedstock was pretreated and/or enzymatically hydrolyzed prior to fermentation to make a fermentable substrate. Hydrogen production by Caldicellulosiruptor saccharolyticus, Thermotoga elfii and T. neapolitana on all substrates was observed. Nutrient

  8. Bacteria-Targeting Nanoparticles for Managing Infections

    Science.gov (United States)

    Radovic-Moreno, Aleksandar Filip

    Bacterial infections continue to be a significant concern particularly in healthcare settings and in the developing world. Current challenges include the increasing spread of drug resistant (DR) organisms, the side effects of antibiotic therapy, the negative consequences of clearing the commensal bacterial flora, and difficulties in developing prophylactic vaccines. This thesis was an investigation of the potential of a class of polymeric nanoparticles (NP) to contribute to the management of bacterial infections. More specifically, steps were taken towards using these NPs (1) to achieve greater spatiotemporal control over drug therapy by more targeted antibiotic delivery to bacteria, and (2) to develop a prophylactic vaccine formulation against the common bacterial sexually transmitted disease (STD) caused by Chlamydia trachomatis. In the first part, we synthesized polymeric NPs containing poly(lactic-co-glycolic acid)-block-poly(L-histidine)-block-poly(ethylene glycol) (PLGA-PLH-PEG). We show that these NPs are able to bind to bacteria under model acidic infection conditions and are able to encapsulate and deliver vancomycin to inhibit the growth of Staphylococcus aureus bacteria in vitro. Further work showed that the PLGA-PLH-PEG-based NPs demonstrated the potential for competition for binding bacteria at a site of infection from soluble protein and model phagocytic and tissue-resident cells in a NP composition dependent manner. The NPs demonstrated low toxicity in vitro, were well tolerated by mice in vivo, and circulated in the blood on timescales comparable to control PLGA-PEG NPs. In the second part, we used PLGA-PLH-PEG-based NPs to design a prophylactic vaccine against the obligate intracellular bacterium Chlamydia trachomatis, the most common cause of bacterial STD in the world. Currently, no vaccines against this pathogen are approved for use in humans. We first formulated NPs encapsulating the TLR7 agonist R848 conjugated to poly(lactic acid) (R848-PLA

  9. Isolation and Presumptive Identification of Adherent Epithelial Bacteria (“Epimural” Bacteria) from the Ovine Rumen Wall

    OpenAIRE

    Mead, Lorna J.; Jones, G. A.

    1981-01-01

    One hundred sixty-one strains of adherent bacteria were isolated under anaerobic conditions from four sites on the rumen epithelial surface of sheep fed hay or a hay-grain ration. Before isolation of bacteria, rumen tissue was washed six times in an anaerobic dilution solution, and viable bacteria suspended in the washings were counted. Calculation indicated that unattached bacteria would have been removed from the tissue by this procedure, but a slow and progressive release of attached bacte...

  10. Label and label-free based surface-enhanced Raman scattering for pathogen bacteria detection: A review.

    Science.gov (United States)

    Liu, Yu; Zhou, Haibo; Hu, Ziwei; Yu, Guangxia; Yang, Danting; Zhao, Jinshun

    2017-08-15

    Rapid, accurate detection of pathogen bacteria is a highly topical research area for the sake of food safety and public health. Surface-enhanced Raman scattering (SERS) is being considered as a powerful and attractive technique for pathogen bacteria detection, due to its sensitivity, high speed, comparatively low cost, multiplexing ability and portability. This contribution aims to give a comprehensive overview of SERS as a technique for rapid detection of pathogen bacteria based on label and label-free strategies. A brief tutorial on SERS is given first of all. Then we summarize the recent trends and developments of label and label-free based SERS applied to detection of pathogen bacteria, including the relatively complete interpretation of SERS spectra. In addition, multifunctional SERS platforms for pathogen bacteria in matrix are discussed as well. Furthermore, an outlook of the work done and a perspective on the future directions of SERS as a reliable tool for real-time pathogen bacteria detection are given. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Bacteria isolated from bats inhibit the growth of Pseudogymnoascus destructans, the causative agent of white-nose syndrome.

    Science.gov (United States)

    Hoyt, Joseph R; Cheng, Tina L; Langwig, Kate E; Hee, Mallory M; Frick, Winifred F; Kilpatrick, A Marm

    2015-01-01

    Emerging infectious diseases are a key threat to wildlife. Several fungal skin pathogens have recently emerged and caused widespread mortality in several vertebrate groups, including amphibians, bats, rattlesnakes and humans. White-nose syndrome, caused by the fungal skin pathogen Pseudogymnoascus destructans, threatens several hibernating bat species with extinction and there are few effective treatment strategies. The skin microbiome is increasingly understood to play a large role in determining disease outcome. We isolated bacteria from the skin of four bat species, and co-cultured these isolates with P. destructans to identify bacteria that might inhibit or kill P. destructans. We then conducted two reciprocal challenge experiments in vitro with six bacterial isolates (all in the genus Pseudomonas) to quantify the effect of these bacteria on the growth of P. destructans. All six Pseudomonas isolates significantly inhibited growth of P. destructans compared to non-inhibitory control bacteria, and two isolates performed significantly better than others in suppressing P. destructans growth for at least 35 days. In both challenge experiments, the extent of suppression of P. destructans growth was dependent on the initial concentration of P. destructans and the initial concentration of the bacterial isolate. These results show that bacteria found naturally occurring on bats can inhibit the growth of P. destructans in vitro and should be studied further as a possible probiotic to protect bats from white-nose syndrome. In addition, the presence of these bacteria may influence disease outcomes among individuals, populations, and species.

  12. Bacteria isolated from bats inhibit the growth of Pseudogymnoascus destructans, the causative agent of white-nose syndrome.

    Directory of Open Access Journals (Sweden)

    Joseph R Hoyt

    Full Text Available Emerging infectious diseases are a key threat to wildlife. Several fungal skin pathogens have recently emerged and caused widespread mortality in several vertebrate groups, including amphibians, bats, rattlesnakes and humans. White-nose syndrome, caused by the fungal skin pathogen Pseudogymnoascus destructans, threatens several hibernating bat species with extinction and there are few effective treatment strategies. The skin microbiome is increasingly understood to play a large role in determining disease outcome. We isolated bacteria from the skin of four bat species, and co-cultured these isolates with P. destructans to identify bacteria that might inhibit or kill P. destructans. We then conducted two reciprocal challenge experiments in vitro with six bacterial isolates (all in the genus Pseudomonas to quantify the effect of these bacteria on the growth of P. destructans. All six Pseudomonas isolates significantly inhibited growth of P. destructans compared to non-inhibitory control bacteria, and two isolates performed significantly better than others in suppressing P. destructans growth for at least 35 days. In both challenge experiments, the extent of suppression of P. destructans growth was dependent on the initial concentration of P. destructans and the initial concentration of the bacterial isolate. These results show that bacteria found naturally occurring on bats can inhibit the growth of P. destructans in vitro and should be studied further as a possible probiotic to protect bats from white-nose syndrome. In addition, the presence of these bacteria may influence disease outcomes among individuals, populations, and species.

  13. Bacteria-Mineral Interactions on the Surfaces of Metal-Resistant Bacteria

    International Nuclear Information System (INIS)

    Malkin, A.J.

    2010-01-01

    The extraordinary ability of indigenous microorganisms, like metal-resistant bacteria, for biotransformation of toxic compounds is of considerable interest for the emerging area of environmental bioremediation. However, the underlying mechanisms by which metal-resistant bacteria transform toxic compounds are currently unknown and await elucidation. The project's objective was to study stress-induced responses of metal-resistant bacteria to environmental changes and chemical stimulants. This project involved a multi-institutional collaboration of our LLNL group with the group of Dr. H.-Y. Holman (Lawrence Berkeley National Laboratory). In this project, we have utilized metal-resistant bacteria Arthrobacter oxydans as a model bacterial system. We have utilized atomic force microscopy (AFM) to visualize for the first time at the nanometer scale formation of stress-induced structures on bacterial surfaces in response to Cr (VI) exposure. We have demonstrated that structure, assembly, and composition of these stress-induced structures are dependent on Cr (VI) concentrations. Our AFM observations of the appearance and development of stress-induced layers on the surfaces of Arthrobacter oxydans bacteria exposed to Cr (VI) were confirmed by Dr. Holman's biochemical, electron microscopy, and synchrotron infrared spectromicroscopy studies. In general, in vitro imaging of live microbial and cellular systems represents one of the most challenging issues in application of AFM. Various approaches for immobilization of bacteria on the substrate for in vitro imaging were tested in this project. Imaging of live bacteria was achieved, however further optimization of experimental methods are needed for high-resolution visualization of the cellular environmental structural dynamics by AFM. This project enhanced the current insight into molecular architecture, structural and environmental variability of bacterial systems. The project partially funded research for two book chapters (1

  14. Screening and characterization of phosphate solubilizing bacteria from isolate of thermophilic bacteria

    Science.gov (United States)

    Yulianti, Evy; Rakhmawati, Anna

    2017-08-01

    The aims of this study were to select bacteria that has the ability to dissolve phosphate from thermophilic bacteria isolates after the Merapi eruption. Five isolates of selected bacteria was characterized and continued with identification. Selection was done by using a pikovskaya selective medium. Bacterial isolates were grown in selective medium and incubated for 48 hours at temperature of 55 ° C. Characterization was done by looking at the cell and colony morphology, physiological and biochemical properties. Identification was done with the Profile Matching method based on the reference genus Oscillospira traced through Bergey's Manual of Determinative Bacteriology. Dendogram was created based on similarity index SSM. The results showed there were 14 isolates of bacteria that were able to dissolve phosphate indicated by a clear zone surrounding the bacterial colony on selective media. Five isolates were selected with the largest clear zone. Isolates D79, D92, D110a, D135 and D75 have different characters. The result of phenotypic characters identification with Genus Oscillospira profile has a percentage of 100% similarity to isolate D92 and D110a; 92.31% for isolates D79, and 84.6% for isolates D75 and D135. Dendogram generated from average linkage algorithm / UPGMA using the Simple Matching Coefficient (SSM) algorithms showed, isolate thermophilic bacteria D75 and D135 are combined together to form cluster 1. D110a and D92 form a sub cluster A. Sub cluster A and D79 form cluster 2

  15. Quorum sensing communication between bacteria and human cells: signals, targets and functions

    Directory of Open Access Journals (Sweden)

    Angelika eHolm

    2014-06-01

    Full Text Available Both direct and long-range interactions between pathogenic Pseudomonas aeruginosa bacteria and their eukaryotic hosts are important in the outcome of infections. For cell-to-cell communication, these bacteria employ the quorum sensing (QS system to pass on information of the density of the bacterial population and collectively switch on virulence factor production, biofilm formation and resistance development. Thus, QS allows bacteria to behave as a community to perform tasks which would be impossible for individual cells, e.g. to overcome defense and immune systems and establish infections in higher organisms. This review highlights these aspects of QS and our own recent research on how P.aeruginosa communicates with human cells using the small QS signal molecules N-acyl homoserine lactones (AHL. We focus on how this conversation changes the behavior and function of neutrophils, macrophages and epithelial cells and on how the signaling machinery in human cells responsible for the recognition of AHL. Understanding the bacteria-host relationships at both cellular and molecular levels is essential for the identification of new targets and for the development of novel strategies to fight bacterial infections in the future.

  16. Laser thermal ablation of multidrug-resistant bacteria using functionalized gold nanoparticles

    Directory of Open Access Journals (Sweden)

    Mocan L

    2017-03-01

    Full Text Available Lucian Mocan,1,2 Flaviu A Tabaran,3 Teodora Mocan,2,4 Teodora Pop,5 Ofelia Mosteanu,5 Lucia Agoston-Coldea,6 Cristian T Matea,2 Diana Gonciar,2 Claudiu Zdrehus,1,2 Cornel Iancu1 13rd Department of General Surgery, “Iuliu Hatieganu” University of Medicine and Pharmacy, 2Department of Nanomedicine, “Octavian Fodor” Gastroenterology Institute, 3Department of Pathology, University of Agricultural Sciences and Veterinary Medicine, Faculty of Veterinary Medicine, 4Department of Physiology, 53rd Gastroenterology Department, 6Department of Internal Medicine, “Iuliu Hatieganu” University of Medicine and Pharmacy, Cluj-Napoca, Romania Abstract: The issue of multidrug resistance (MDR has become an increasing threat to public health. One alternative strategy against MDR bacteria would be to construct therapeutic vectors capable of physically damaging these microorganisms. Gold nanoparticles hold great promise for the development of such therapeutic agents, since the nanoparticles exhibit impressive properties, of which the most important is the ability to convert light into heat. This property has scientific significance since is exploited to develop nano-photothermal vectors to destroy bacteria at a molecular level. The present paper summarizes the latest advancements in the field of nanotargeted laser hyperthermia of MDR bacteria mediated by gold nanoparticles. Keywords: bacteria, photo-thermal ablation, gold nanoparticles, antibiotic resistance

  17. Interactions of the cell-wall glycopolymers of lactic acid bacteria with their bacteriophages

    Directory of Open Access Journals (Sweden)

    Marie-Pierre eChapot-Chartier

    2014-05-01

    Full Text Available Lactic acid bacteria (LAB are Gram positive bacteria widely used in the production of fermented food in particular cheese and yoghurts. Bacteriophage infections during fermentation processes have been for many years a major industrial concern and have stimulated numerous research efforts. Better understanding of the molecular mechanisms of bacteriophage interactions with their host bacteria is required for the development of efficient strategies to fight against infections. The bacterial cell wall plays key roles in these interactions. First, bacteriophages must adsorb at the bacterial surface through specific interactions with receptors that are cell wall components. At next step, phages must overcome the barrier constituted by cell wall peptidoglycan to inject DNA inside bacterial cell. Also at the end of the infection cycle, phages synthesize endolysins able to hydrolyze peptidoglycan and lyse bacterial cells to release phage progeny. In the last decade, concomitant development of genomics and structural analysis of cell wall components allowed considerable advances in the knowledge of their structure and function in several model LAB. Here, we describe the present knowledge on the structure of the cell wall glycopolymers of the best characterized LAB emphasizing their structural variations and we present the available data regarding their role in bacteria-phage specific interactions at the different steps of the infection cycle.

  18. Antibacterial activity of Pinus elliottii against anaerobic bacteria present in primary endodontic infections.

    Science.gov (United States)

    Caetano da Silva, Sandro Donizete; Mendes de Souza, Maria Gorete; Oliveira Cardoso, Miguel Jorge; da Silva Moraes, Thais; Ambrósio, Sérgio Ricardo; Sola Veneziani, Rodrigo Cássio; Martins, Carlos Henrique G

    2014-12-01

    activity revealed significant results--MICB50 lay between 7.8 and 62.5 μg/mL, and dehydroabietic acid prevented all the evaluated bacteria from forming a biofilm. Hence, the chemical constituents of P. elliottii are promising biomolecules to develop novel therapeutic strategies to fight against endodontic infections. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Screening and biological characteristics of fufenozide degrading bacteria

    Science.gov (United States)

    Xu, Chenhao; Gong, Mingfu; Guan, Qinlan; Deng, Xia; Deng, Hongyan; Huang, Jiao

    2018-04-01

    Fufenozide was a novel pesticide for the control of Lepidoptera pests, which was highly toxic to silkworm. Fufenozide-contaminated soil samples were collected and the bacteria that degrade fufenozide were isolated and screened by selective medium. The colony characteristics, cell characteristics and degradation characteristics in different concentrations fufenozide of the fufenozide degrading bacteria were studied. The results indicated that seven strains of fufenozide degradeing bacteria, named as DDH01, DDH03, DDH04, DDH04, DDH05, DDH07 and DDH07 respectively, were isolated from soil contaminated with fufenozide. DDH01, DDH02, DDH04 and DDH05 of seven fufenozide degrading bacteria, was gram-positive bacteria, and DDH03, DDH06 and DDH07 was gram-negative bacteria. All of seven strains of fufenozide degrading bacteria were not spores, weeks flagella, rod-shaped bacteria. DDH06 and DDH07 had capsules, and the remaining five strains had not capsule. The colonies formed by seven strains of fufenozide degradation bacteria on beef extract peptone medium plate were milky white colonies with irregular edges, thinner lawn, smaller colony with smooth surface. The growth of 7 strains of fufenozide degradation bacteria was significantly affected by the concentration of fufenozide, All of 7 strains grown in the range from 0.00025 g/mL to 1 g/mL of 10% fufenozide suspension. DDH2 was the best among the 7 strains of fufenozide degrading bacteria grown in 10% fufenozide suspension medium.

  20. In vitro model of production of antibodies; a new approach to reveal the presence of key bacteria in polymicrobial environments.

    Science.gov (United States)

    Wu, Chongcong; Nakka, Sravya; Mansouri, Sepahdar; Bengtsson, Torbjörn; Nayeri, Tayeb; Nayeri, Fariba

    2016-09-09

    There is a rapid emergence of multiple resistant gram-negative bacteria due to overuse of antibiotics in the treatment of infections. Biofilms consist of polymicrobial communities that survive the host's defense system. The key bacteria in biofilms are slow growing and support an attachment and rapid growth of other microorganisms. Current antimicrobial strategies often fail due to poor diagnosis of key pathogens in biofilms. The study aims to develop anti-bacterial human antibodies in vitro from patients who had recently undergone a systemic infection by pathogenic bacteria and to use these antibodies as a tool for detecting bacteria in biofilms. Lymphocytes were separated from whole blood of patients (n = 10) and stimulated with heat-killed bacteria to produce antibodies in vitro. The specificity of antibodies in recognizing the bacteria against which they were directed was evaluated by surface plasmon resonance system (SPR) and electron microscopy. The ulcer secretions from patients with chronic and acute leg ulcers and healthy controls were analyzed by the SPR system and the results were compared with culture studies. The produced antibodies recognized bacteria with high sensitivity (SPR). The antibodies against Enterococcus fecalis bound specifically to the microorganism in a bacterial co-culture that was visualized by electron microscopy. In the present work, a method for producing specific antibodies against bacteria is introduced to recognize bacterial components in body fluids of patients suffering from pathogenic biofilms. This diagnostic technique may be most useful in clinical microbiology and in the choice of antibiotics in the treatment of serious infections.

  1. Probiotic bacteria: selective enumeration and survival in dairy foods.

    Science.gov (United States)

    Shah, N P

    2000-04-01

    A number of health benefits have been claimed for probiotic bacteria such as Lactobacillus acidophilus, Bifidobacterium spp., and Lactobacillus casei. Because of the potential health benefits, these organisms are increasingly incorporated into dairy foods. However, studies have shown low viability of probiotics in market preparations. In order to assess viability of probiotic bacteria, it is important to have a working method for selective enumeration of these probiotic bacteria. Viability of probiotic bacteria is important in order to provide health benefits. Viability of probiotic bacteria can be improved by appropriate selection of acid and bile resistant strains, use of oxygen impermeable containers, two-step fermentation, micro-encapsulation, stress adaptation, incorporation of micronutrients such as peptides and amino acids and by sonication of yogurt bacteria. This review will cover selective enumeration and survival of probiotic bacteria in dairy foods.

  2. Quantification of Faecalibacterium prausnitzii- and Subdoligranulum variabile-like bacteria in the cecum of chickens by real-time PCR

    DEFF Research Database (Denmark)

    Lund, Marianne; Friis-Holm, Lotte Bjerrum; Pedersen, Karl

    2010-01-01

    The intestinal microbial community is playing an important role in health and production performance of chickens. To understand the effect on the intestinal microflora induced by various feeding strategies, feed additives, infections, and intestinal disorders, it is important to have methods......, and in hatcher material. Quantification of this group of F. prausnitzii-S. variabile-like bacteria has not been performed before by real-time PCR, but results confirm previous results obtained by cloning and sequencing showing that the F. prausnitzii-S. variabile-like group of bacteria constitutes a major...

  3. Introduce of Viable But Nonculturable Bacteria

    Directory of Open Access Journals (Sweden)

    Mehdi Hassanshahian

    2008-03-01

    Full Text Available Viable-But-Nonculturable-State (VBNC is the condition in which bacteria fail to grow on their routine bacteriological media where they would normally grow and develop into colonies, but are still alive and capable of renewed metabolic activity. VBNC state is useful for evaluating public health and for ascertaining the sterility of drinking water, pharmaceuticals, and foodstuff. A number of bacteria, mostly pathogenic to humans, have been proved to enter into this state in response to natural stresses such as starvation, incubation out of optimum growth temperature, increased osmotic pressure, etc. Once in the VBNC state, they undergo various physiological, structural, and genetic alterations. These alterations result in reduced cell size, conversion from bacilli to coccid, thickened cell walls, and peptidoglycan gaining many cross links. Metabolic changes also occur that include reductions in growth, nutrient transport, and respiratory rate; biosynthesis of new protein, and ATP remaining at a constant level. It has been shown that in the VBNC state, some pathogens conserve their virulence properties. Gene expression continues in the VBNC cell. Nucleic acids remain intact in the early VBNC phase but they gradually undergo degradation with prolonged VBNC. Cytological methods such as direct viable count and reduction of tetrazolium salts, and molecular methods such as reverse transcription polymerase chain reaction and green fluorescent protein have been used for the study of VBNC. Resuscitation from VBNC state starts when the inducing factor(s is/are lifted. Factors that help the resuscitation of VBNC bacteria include addition of certain nutrients and chemicals, introduction of a few culturable cells into the VBNC cell population, and passage through the animal host. As virulence properties are sustained during the VBNC phase, special care must be paid when evaluating sterility of drinking water.

  4. Catecholate siderophores protect bacteria from pyochelin toxicity.

    Directory of Open Access Journals (Sweden)

    Conrado Adler

    Full Text Available Bacteria produce small molecule iron chelators, known as siderophores, to facilitate the acquisition of iron from the environment. The synthesis of more than one siderophore and the production of multiple siderophore uptake systems by a single bacterial species are common place. The selective advantages conferred by the multiplicity of siderophore synthesis remains poorly understood. However, there is growing evidence suggesting that siderophores may have other physiological roles besides their involvement in iron acquisition.Here we provide the first report that pyochelin displays antibiotic activity against some bacterial strains. Observation of differential sensitivity to pyochelin against a panel of bacteria provided the first indications that catecholate siderophores, produced by some bacteria, may have roles other than iron acquisition. A pattern emerged where only those strains able to make catecholate-type siderophores were resistant to pyochelin. We were able to associate pyochelin resistance to catecholate production by showing that pyochelin-resistant Escherichia coli became sensitive when biosynthesis of its catecholate siderophore enterobactin was impaired. As expected, supplementation with enterobactin conferred pyochelin resistance to the entE mutant. We observed that pyochelin-induced growth inhibition was independent of iron availability and was prevented by addition of the reducing agent ascorbic acid or by anaerobic incubation. Addition of pyochelin to E. coli increased the levels of reactive oxygen species (ROS while addition of ascorbic acid or enterobactin reduced them. In contrast, addition of the carboxylate-type siderophore, citrate, did not prevent pyochelin-induced ROS increases and their associated toxicity.We have shown that the catecholate siderophore enterobactin protects E. coli against the toxic effects of pyochelin by reducing ROS. Thus, it appears that catecholate siderophores can behave as protectors of

  5. Repair by genetic recombination in bacteria: overview

    International Nuclear Information System (INIS)

    Howard-Flanders, P.

    1975-01-01

    DNA molecules that have been damaged in both strands at the same level are not subject to repair by excision but instead can be repaired through recombination with homologous molecules. Examples of two-strand damage include postreplication gaps opposite pyrimidine dimers, two-strand breaks produced by x-rays, and chemically induced interstrand cross-links. In ultraviolet-irradiated bacteria, and newly synthesized DNA is of length equal to the interdimer spacing. With continued incubation, this low-molecular-weight DNA is joined into high-molecular-weight chains (postreplication repair), a process associated with sister exchanges in bacteria. Recombination is initiated by pyrimidine dimers opposite postreplication gaps and by interstrand cross-links that have been cut by excision enzymes. The free ends at the resulting gaps presumably initiate the exchanges. Postreplication repair in Escherichia coli occurs in recB - and recC - but is greatly slowed in recF - mutants. RecB and recC are the structural genes for exonuclease V, which digests two-stranded DNA by releasing oligonucleotides first from one strand and then from the other. The postreplication sister exchanges in ultraviolet-irradiated bacteria result in the distribution of pyrimidine dimers between parental and daughter strands, indicating that long exchanges involving both strands of each duplex occur. The R1 restriction endonuclease from E. coli has been used to cut the DNA of a bacterial drug-resistance transfer factor with one nuclease-sensitive site, and also DNA from the frog Xenopus enriched for ribosomal 18S and 28S genes. The fragments were annealed with the cut plasmid DNA and ligated, producing a new larger plasmid carrying the eukaryotic rDNA and able to infect and replicate in E. coli

  6. Close Encounters of Lymphoid Cells and Bacteria

    Science.gov (United States)

    Cruz-Adalia, Aranzazu; Veiga, Esteban

    2016-01-01

    During infections, the first reaction of the host against microbial pathogens is carried out by innate immune cells, which recognize conserved structures on pathogens, called pathogen-associated molecular patterns. Afterward, some of these innate cells can phagocytose and destroy the pathogens, secreting cytokines that would modulate the immune response to the challenge. This rapid response is normally followed by the adaptive immunity, more specific and essential for a complete pathogen clearance in many cases. Some innate immune cells, usually named antigen-presenting cells, such as macrophages or dendritic cells, are able to process internalized invaders and present their antigens to lymphocytes, triggering the adaptive immune response. Nevertheless, the traditional boundary of separated roles between innate and adaptive immunity has been blurred by several studies, showing that very specialized populations of lymphocytes (cells of the adaptive immunity) behave similarly to cells of the innate immunity. These “innate-like” lymphocytes include γδ T cells, invariant NKT cells, B-1 cells, mucosal-associated invariant T cells, marginal zone B cells, and innate response activator cells, and together with the newly described innate lymphoid cells are able to rapidly respond to bacterial infections. Strikingly, our recent data suggest that conventional CD4+ T cells, the paradigm of cells of the adaptive immunity, also present innate-like behavior, capturing bacteria in a process called transinfection. Transinfected CD4+ T cells digest internalized bacteria like professional phagocytes and secrete large amounts of proinflammatory cytokines, protecting for further bacterial challenges. In the present review, we will focus on the data showing such innate-like behavior of lymphocytes following bacteria encounter. PMID:27774092

  7. Electroactive biofilms of sulphate reducing bacteria

    International Nuclear Information System (INIS)

    Cordas, Cristina M.; Guerra, L. Tiago; Xavier, Catarina; Moura, Jose J.G.

    2008-01-01

    Biofilms formed from a pure strain of Desulfovibrio desulfuricans 27774 on stainless steel and graphite polarised surfaces were studied. The polarisation conditions applied were -0.4 V vs. SCE for different times. A cathodic current related with the biofilms growth was observed with a maximum intensity of -270 mA m -2 that remained stable for several days using graphite electrodes. These sulphate reducing bacteria biofilms present electrocatalytic activity towards hydrogen and oxygen reduction reactions. Electrode polarisation has a selective effect on the catalytic activity. The biofilms were also observed by scanning electronic microscopy revealing the formation of homogeneous films on the surfaces

  8. Isolation and biochemical characterizations of the bacteria ...

    African Journals Online (AJOL)

    These isolates yielded off white convex colonies on potato dextrose agar (PDA) media at 29°C with 1.7 to 1.9 mm diameter and were yellow on yeast extract dextrose chalk agar (YDC) media at 27°C with 1.8 to 2.0 mm diameter. The bacteria were rod shape measuring 0.5 to 0.6 × 1.4 to 1.6 μm on PDA and 0.6 to 0.7 × 1.5 to ...

  9. Bioluminescent bacteria: lux genes as environmental biosensors

    Directory of Open Access Journals (Sweden)

    Nunes-Halldorson Vânia da Silva

    2003-01-01

    Full Text Available Bioluminescent bacteria are widespread in natural environments. Over the years, many researchers have been studying the physiology, biochemistry and genetic control of bacterial bioluminescence. These discoveries have revolutionized the area of Environmental Microbiology through the use of luminescent genes as biosensors for environmental studies. This paper will review the chronology of scientific discoveries on bacterial bioluminescence and the current applications of bioluminescence in environmental studies, with special emphasis on the Microtox toxicity bioassay. Also, the general ecological significance of bioluminescence will be addressed.

  10. Polymorphic transformation of helical flagella of bacteria

    Science.gov (United States)

    Lim, Sookkyung; Howard Berg Collaboration; William Ko Collaboration; Yongsam Kim Collaboration; Wanho Lee Collaboration; Charles Peskin Collaboration

    2016-11-01

    Bacteria such as E. coli swim in an aqueous environment by utilizing the rotation of flagellar motors and alternate two modes of motility, runs and tumbles. Runs are steady forward swimming driven by bundles of flagellar filaments whose motors are turning CCW; tumbles involve a reorientation of the direction of swimming triggered by motor reversals. During tumbling, the helical flagellum undergoes polymorphic transformations, which is a local change in helical pitch, helical radius, and handedness. In this work, we investigate the underlying mechanism of structural conformation and how this polymorphic transition plays a role in bacterial swimming. National Science Foundation.

  11. Ethylene-producing bacteria that ripen fruit.

    Science.gov (United States)

    Digiacomo, Fabio; Girelli, Gabriele; Aor, Bruno; Marchioretti, Caterina; Pedrotti, Michele; Perli, Thomas; Tonon, Emil; Valentini, Viola; Avi, Damiano; Ferrentino, Giovanna; Dorigato, Andrea; Torre, Paola; Jousson, Olivier; Mansy, Sheref S; Del Bianco, Cristina

    2014-12-19

    Ethylene is a plant hormone widely used to ripen fruit. However, the synthesis, handling, and storage of ethylene are environmentally harmful and dangerous. We engineered E. coli to produce ethylene through the activity of the ethylene-forming enzyme (EFE) from Pseudomonas syringae. EFE converts a citric acid cycle intermediate, 2-oxoglutarate, to ethylene in a single step. The production of ethylene was placed under the control of arabinose and blue light responsive regulatory systems. The resulting bacteria were capable of accelerating the ripening of tomatoes, kiwifruit, and apples.

  12. Are Bacteria more dangerous in space?

    International Nuclear Information System (INIS)

    Leys, N.; Baatout, S.

    2010-01-01

    With a mission to Mars and a permanent base on the moon as the ultimate dream, space travel is continually pushing back the frontiers. But long space missions present great challenges for science, for example in the field of microbiology. Together with the European Space Agency (ESA), SCK-CEN is studying the effects of space travel conditions on the behaviour of bacteria. In 2009 the SCK-CEN experts completed four innovative research projects at the cutting edge of microbiology, radiation sciences and space travel.

  13. Electroactive biofilms of sulphate reducing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Cordas, Cristina M.; Guerra, L. Tiago; Xavier, Catarina [Requimte-CQFB, Departamento de Quimica, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Moura, Jose J.G. [Requimte-CQFB, Departamento de Quimica, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal)], E-mail: jose.moura@dq.fct.unl.pt

    2008-12-01

    Biofilms formed from a pure strain of Desulfovibrio desulfuricans 27774 on stainless steel and graphite polarised surfaces were studied. The polarisation conditions applied were -0.4 V vs. SCE for different times. A cathodic current related with the biofilms growth was observed with a maximum intensity of -270 mA m{sup -2} that remained stable for several days using graphite electrodes. These sulphate reducing bacteria biofilms present electrocatalytic activity towards hydrogen and oxygen reduction reactions. Electrode polarisation has a selective effect on the catalytic activity. The biofilms were also observed by scanning electronic microscopy revealing the formation of homogeneous films on the surfaces.

  14. Bacteria-Triggered Release of Antimicrobial Agents

    DEFF Research Database (Denmark)

    Komnatnyy, Vitaly V.; Chiang, Wen-Chi; Tolker-Nielsen, Tim

    2014-01-01

    Medical devices employed in healthcare practice are often susceptible to microbial contamination. Pathogenic bacteria may attach themselves to device surfaces of catheters or implants by formation of chemically complex biofilms, which may be the direct cause of device failure. Extracellular...... bacterial lipases are particularly abundant at sites of infection. Herein it is shown how active or proactive compounds attached to polymeric surfaces using lipase‐sensitive linkages, such as fatty acid esters or anhydrides, may be released in response to infection. Proof‐of‐concept of the responsive...

  15. Anaerobic bacteria as producers of antibiotics.

    Science.gov (United States)

    Behnken, Swantje; Hertweck, Christian

    2012-10-01

    Anaerobic bacteria are the oldest terrestrial creatures. They occur ubiquitously in soil and in the intestine of higher organisms and play a major role in human health, ecology, and industry. However, until lately no antibiotic or any other secondary metabolite has been known from anaerobes. Mining the genome sequences of Clostridium spp. has revealed a high prevalence of putative biosynthesis genes (PKS and NRPS), and only recently the first antibiotic from the anaerobic world, closthioamide, has been isolated from the cellulose degrading bacterium Clostridium cellulolyticum. The successful genetic induction of antibiotic biosynthesis in an anaerobe encourages further investigations of obligate anaerobes to tap their hidden biosynthetic potential.

  16. Heterotrophic bacteria in soils of Larsemann Oasis of East Antarctica

    Science.gov (United States)

    Churilin, Nikita; Soina, Vera

    2015-04-01

    Antarctic soils. Primitive soils and permafrost layer have a great unevenness in the number of cultivated and potentially viable cells in different horizons. This phenomenon is characteristic for habitats with stable and alternating negative temperatures that can be attributed to the irregular migration of cells during freezing and heterogeneity of microbial populations along the depth of dormancy. One of the identified features was the lack of correlation with the organic content. SEM study of microbial communities in native Antarctic soils revealed the presence of biofilms, which can play an important role in weathering of rocks and primary soil formation, by forming organic horizon and protecting cells from environmental impact. Biofilms can also influence on distribution of bacterial cells in forming soils. Growth regulators (indoleacetic acid, wheat germ agglutinin, alkylhydroxybenzenes, pyruvate Na and serotonin) were used in experiments on the growth reactivation using soil samples with low number of microorganisms. The results obtained by this analysis can be used for further research to develop methods of the most complete selection of viable bacteria from Antarctic soils. We also determined the physiological condition of bacterial populations and their maximum specific growth rate. This method determines the functional (trophic) diversity of microbial communities and the maximum specific growth rate that reflects the environmental strategy of bacterial growth. In spite of the extreme conditions, a variety of physiological and metabolic willingness to consume polymers hydrolytic bacterial associations of endolithic soil is highest in the surface horizon and sharply decreases in the mineral horizon.

  17. Diffusible signal factor-dependent quorum sensing in pathogenic bacteria and its exploitation for disease control.

    Science.gov (United States)

    Dow, J M

    2017-01-01

    Cell-to-cell signals of the diffusible signal factor (DSF) family are cis-2-unsaturated fatty acids of differing chain length and branching pattern. DSF signalling has been described in diverse bacteria to include plant and human pathogens where it acts to regulate functions such as biofilm formation, antibiotic tolerance and the production of virulence factors. DSF family signals can also participate in interspecies signalling with other bacteria and interkingdom signalling such as with the yeast Candida albicans. Interference with DSF signalling may afford new opportunities for the control of bacterial disease. Such strategies will depend in part on detailed knowledge of the molecular mechanisms underlying the processes of signal synthesis, perception and turnover. Here, I review both recent progress in understanding DSF signalling at the molecular level and prospects for translating this knowledge into approaches for disease control. © 2016 The Society for Applied Microbiology.

  18. Modeling how soluble microbial products (SMP) support heterotrophic bacteria in autotroph-based biofilms

    DEFF Research Database (Denmark)

    Merkey, Brian; Rittmann, Bruce E.; Chopp, David L.

    2009-01-01

    . In this paper, we develop and use a mathematical model to describe a model biofilm system that includes autotrophic and heterotrophic bacteria and the key products produced by the bacteria. The model combines the methods of earlier multi-species models with a multi-component biofilm model in order to explore...... the interaction between species via exchange of soluble microbial products (SMP). We show that multiple parameter sets are able to describe the findings of experimental studies, and that heterotrophs growing on autotrophically produced SMP may pursue either r- or K-strategies to sustain themselves when SMP...... is their only substrate. We also show that heterotrophs can colonize some distance from the autotrophs and still be sustained by autotrophically produced SMP. This work defines the feasible range of parameters for utilization of SMP by heterotrophs and the nature of the interactions between autotrophs...

  19. Endospore-forming bacteria as an indicator of pollution in sediments of Lake Geneva

    Directory of Open Access Journals (Sweden)

    Bueche M.

    2013-04-01

    Full Text Available Treated wastewater and runoff-water is released by the outlet of the sewage treatment plant of Vidy (Lausanne directly into the Lake of Geneva via a pipe located 300m from the shore. Even if this water is properly treated with modern technologies, we can observe an accumulation of micro pollutants into the sediments, and particularly heavy-metals. The main objective of this project is to investigate how these elevated concentrations of heavy metals affect both abundance and diversity of prokaryotes in the sediments. A special emphasis was given to endospore-forming bacteria, which could use sporulation as a survival strategy to resist in highly contaminated areas. This study could have implications both for understanding the role of endospore-forming bacteria in the environment as well as in terms of improving the bioremediation processes.

  20. Growth and chemosensory behavior of sulfate-reducing bacteria in oxygen-sulfide gradients

    DEFF Research Database (Denmark)

    Sass, Andrea M.; Wieland, Andrea Eschemann; Kühl, Michael

    2002-01-01

    Growth and chemotactic behavior in oxic–anoxic gradients were studied with two freshwater and four marine strains of sulfate-reducing bacteria related to the genera Desulfovibrio, Desulfomicrobium or Desulfobulbus. Cells were grown in oxygen–sulfide counter-gradients within tubes filled with agar...... chemotactically to lactate, nitrate, sulfate and thiosulfate, and even sulfide functioned as an attractant. In oxic–anoxic gradients the bacteria moved away from high oxygen concentrations and formed bands at the outer edge of the oxic zone at low oxygen concentration (... to actively change the extension and slope of the gradients by oxygen reduction with lactate or even sulfide as electron donor. Generally, the chemotactic behavior was in agreement with a defense strategy that re-establishes anoxic conditions, thus promoting anaerobic growth and, in a natural community...

  1. Anti-virulence approaches and novel peptidomimetics for combating resistant and biofilm associated bacteria

    DEFF Research Database (Denmark)

    Liu, Yang

    Anti-virulence approaches and novel peptidomimetics for combating resistant and biofilm associated bacteria The misuse and overuse of antibiotics has a broad impact on the environment. Antibiotic resistance has become a major threat for modern medical treatment of infectious diseases. There are m......Anti-virulence approaches and novel peptidomimetics for combating resistant and biofilm associated bacteria The misuse and overuse of antibiotics has a broad impact on the environment. Antibiotic resistance has become a major threat for modern medical treatment of infectious diseases...... consisting of microcolonies embedded in self-produced extracellular polymer substances (EPS). EPS can contribute to cell-cell adhesion and restrict antibiotic penetration. Biofilm cells show much greater resistance to stressful conditions than their free-living counterparts. Conventional treatment strategies...

  2. Interactive Control System, Intended Strategy, Implemented Strategy dan Emergent Strategy

    Directory of Open Access Journals (Sweden)

    Tubagus Ismail

    2012-09-01

    Full Text Available The purpose of this study was to examine the relationship between management control system (MCS and strategy formation processes, namely: intended strategy, emergent strategy and impelemented strategy. The focus of MCS in this study was interactive control system. The study was based on Structural Equation Modeling (SEM as its multivariate analyses instrument. The samples were upper middle managers of manufacturing company in Banten Province, DKI Jakarta Province and West Java Province. AMOS Software 16 program is used as an additional instrument to resolve the problem in SEM modeling. The study found that interactive control system brought a positive and significant influence on Intended strategy; interactive control system brought a positive and significant influence on implemented strategy; interactive control system brought a positive and significant influence on emergent strategy. The limitation of this study is that our empirical model only used one way relationship between the process of strategy formation and interactive control system.

  3. Bacteria in atmospheric waters: Detection, characteristics and implications

    Science.gov (United States)

    Hu, Wei; Niu, Hongya; Murata, Kotaro; Wu, Zhijun; Hu, Min; Kojima, Tomoko; Zhang, Daizhou

    2018-04-01

    In this review paper, we synthesize the current knowledges about bacteria in atmospheric waters, e.g., cloud, fog, rain, and snow, most of which were obtained very recently. First, we briefly describe the importance of bacteria in atmospheric waters, i.e., the essentiality of studying bacteria in atmospheric waters in understanding aerosol-cloud-precipitation-climate interactions in the Earth system. Next, approaches to collect atmospheric water samples for the detection of bacteria and methods to identify the bacteria are summarized and compared. Then the available data on the abundance, viability and community composition of bacteria in atmospheric waters are summarized. The average bacterial concentration in cloud water was usually on the order 104-105 cells mL-1, while that in precipitation on the order 103-104 cells mL-1. Most of the bacteria were viable or metabolically active. Their community composition was highly diverse and differed at various sites. Factors potentially influencing the bacteria, e.g., air pollution levels and sources, meteorological conditions, seasonal effect, and physicochemical properties of atmospheric waters, are described. After that, the implications of bacteria present in atmospheric waters, including their effect on nucleation in clouds, atmospheric chemistry, ecosystems and public health, are briefly discussed. Finally, based on the current knowledges on bacteria in atmospheric waters, which in fact remains largely unknown, we give perspectives that should be paid attention to in future studies.

  4. The effect of lactic acid bacteria on cocoa bean fermentation.

    Science.gov (United States)

    Ho, Van Thi Thuy; Zhao, Jian; Fleet, Graham

    2015-07-16

    Cocoa beans (Theobroma cacao L.) are the raw material for chocolate production. Fermentation of cocoa pulp by microorganisms is crucial for developing chocolate flavor precursors. Yeasts conduct an alcoholic fermentation within the bean pulp that is essential for the production of good quality beans, giving typical chocolate characters. However, the roles of bacteria such as lactic acid bacteria and acetic acid bacteria in contributing to the quality of cocoa bean and chocolate are not fully understood. Using controlled laboratory fermentations, this study investigated the contribution of lactic acid bacteria to cocoa bean fermentation. Cocoa beans were fermented under conditions where the growth of lactic acid bacteria was restricted by the use of nisin and lysozyme. The resultant microbial ecology, chemistry and chocolate quality of beans from these fermentations were compared with those of indigenous (control) fermentations. The yeasts Hanseniaspora guilliermondii, Pichia kudriavzevii, Kluyveromyces marxianus and Saccharomyces cerevisiae, the lactic acid bacteria Lactobacillus plantarum, Lactobacillus pentosus and Lactobacillus fermentum and the acetic acid bacteria Acetobacter pasteurianus and Gluconobacter frateurii were the major species found in control fermentations. In fermentations with the presence of nisin and lysozyme, the same species of yeasts and acetic acid bacteria grew but the growth of lactic acid bacteria was prevented or restricted. These beans underwent characteristic alcoholic fermentation where the utilization of sugars and the production of ethanol, organic acids and volatile compounds in the bean pulp and nibs were similar for beans fermented in the presence of lactic acid bacteria. Lactic acid was produced during both fermentations but more so when lactic acid bacteria grew. Beans fermented in the presence or absence of lactic acid bacteria were fully fermented, had similar shell weights and gave acceptable chocolates with no differences

  5. Metabolism of polychlorinated biphenyls by marine bacteria

    International Nuclear Information System (INIS)

    Carey, A.E.; Harvey, G.R.

    1978-01-01

    There have been no reports of laboratory studies of PCB metabolism by marine organisms. A few workers have analyzed marine animals for products of PCB metabolism. A search for hydroxylated PCBs in marine fish proved inconclusive. Phenolic metabolites of PCBs have been identified in seals and guillemot. PCBs that had been hydroxylated and excreted by marine organisms would most likely be found in the sediments, so in our laboratory we conducted a search for these compounds in marine sediments. Two kilograms of organic-rich surface sediment from Buzzards Bay, Massachusetts, were extracted. The phenolic fraction was isolated and analyzed by gas chromatography-mass spectrometry (GC-MS). Neither wide mass scans nor selected mass searches produced any evidence of hydroxylated PCB derivatives. It was felt that if any marine organisms were capable of metabolism of PCBs, some marine bacteria should have that capability. Thus a series of laboratory experiments was conducted to test this possibility. Reported here is the finding of PCB metabolism by marine bacteria in batch culture

  6. Long-term preservation of anammox bacteria.

    Science.gov (United States)

    Rothrock, Michael J; Vanotti, Matias B; Szögi, Ariel A; Gonzalez, Maria Cruz Garcia; Fujii, Takao

    2011-10-01

    Deposit of useful microorganisms in culture collections requires long-term preservation and successful reactivation techniques. The goal of this study was to develop a simple preservation protocol for the long-term storage and reactivation of the anammox biomass. To achieve this, anammox biomass was frozen or lyophilized at two different freezing temperatures (-60°C and in liquid nitrogen (-200°C)) in skim milk media (with and without glycerol), and the reactivation of anammox activity was monitored after a 4-month storage period. Of the different preservation treatments tested, only anammox biomass preserved via freezing in liquid nitrogen followed by lyophilization in skim milk media without glycerol achieved stoichiometric ratios for the anammox reaction similar to the biomass in both the parent bioreactor and in the freshly harvested control treatment. A freezing temperature of -60°C alone, or in conjunction with lyophilization, resulted in the partial recovery of the anammox bacteria, with an equal mixture of anammox and nitrifying bacteria in the reactivated biomass. To our knowledge, this is the first report of the successful reactivation of anammox biomass preserved via sub-zero freezing and/or lyophilization. The simple preservation protocol developed from this study could be beneficial to accelerate the integration of anammox-based processes into current treatment systems through a highly efficient starting anammox biomass.

  7. Bioactivation of Phytoestrogens: Intestinal Bacteria and Health.

    Science.gov (United States)

    Landete, J M; Arqués, J; Medina, M; Gaya, P; de Las Rivas, B; Muñoz, R

    2016-08-17

    Phytoestrogens are polyphenols similar to human estrogens found in plants or derived from plant precursors. Phytoestrogens are found in high concentration in soya, flaxseed and other seeds, fruits, vegetables, cereals, tea, chocolate, etc. They comprise several classes of chemical compounds (stilbenes, coumestans, isoflavones, ellagitannins, and lignans) which are structurally similar to endogenous estrogens but which can have both estrogenic and antiestrogenic effects. Although epidemiological and experimental evidence indicates that intake of phytoestrogens in foods may be protective against certain chronic diseases, discrepancies have been observed between in vivo and in vitro experiments. The microbial transformations have not been reported so far in stilbenes and coumestans. However, isoflavones, ellagitanins, and lignans are metabolized by intestinal bacteria to produce equol, urolithins, and enterolignans, respectively. Equol, urolithin, and enterolignans are more bioavailable, and have more estrogenic/antiestrogenic and antioxidant activity than their precursors. Moreover, equol, urolithins and enterolignans have anti-inflammatory effects and induce antiproliferative and apoptosis-inducing activities. The transformation of isoflavones, ellagitanins, and lignans by intestinal microbiota is essential to be protective against certain chronic diseases, as cancer, cardiovascular disease, osteoporosis, and menopausal symptoms. Bioavailability, bioactivity, and health effects of dietary phytoestrogens are strongly determined by the intestinal bacteria of each individual.

  8. Inoculation of sugarcane with diazotrophic bacteria

    Directory of Open Access Journals (Sweden)

    Nivaldo Schultz

    2014-04-01

    Full Text Available The sugarcane industry, a strategic crop in Brazil, requires technological improvements in production efficiency to increase the crop energy balance. Among the various currently studied alternatives, inoculation with diazotrophic bacteria proved to be a technology with great potential. In this context, the efficiency of a mixture of bacterial inoculant was evaluated with regard to the agronomic performance and N nutrition of sugarcane. The experiment was carried out on an experimental field of Embrapa Agrobiologia, in Seropédica, Rio de Janeiro, using a randomized block, 2 × 3 factorial design (two varieties and three treatments with four replications, totaling 24 plots. The varieties RB867515 and RB72454 were tested in treatments consisting of: inoculation with diazotrophic bacteria, N-fertilized control with 120 kg ha-1 N and absolute control (no inoculation and no N fertilizer. The inoculum was composed of five strains of five diazotrophic species. The yield, dry matter accumulation, total N in the shoot dry matter and the contribution of N by biological fixation were evaluated, using the natural 15N abundance in non-inoculated sugarcane as reference. The bacterial inoculant increased the stalk yield of variety RB72454 similarly to fertilization with 120 kg ha-1 N in the harvests of plant-cane and first ratoon crops, however the contribution of biological N fixation was unchanged by inoculation, indicating that the benefits of the inoculant in sugarcane may have resulted from plant growth promotion.

  9. Beneficial effects of antioxidative lactic acid bacteria

    Directory of Open Access Journals (Sweden)

    Hisako Nakagawa

    2017-01-01

    Full Text Available Oxidative stress is caused by exposure to reactive oxygen intermediates. The oxidative damage of cell components such as proteins, lipids, and nucleic acids one of the important factors associated with diabetes mellitus, cancers and cardiovascular diseases. This occurs as a result of imbalance between the generations of oxygen derived radicals and the organism’s antioxidant potential. The amount of oxidative damage increases as an organism ages and is postulated to be a major causal factor of senescence. To date, many studies have focused on food sources, nutrients, and components that exert antioxidant activity in worms, flies, mice, and humans. Probiotics, live microorganisms that when administered in adequate amounts provide many beneficial effects on the human health, have been attracting growing interest for their health-promoting effects, and have often been administered in fermented milk products. In particular, lactic acid bacteria (LAB are known to conferre physiologic benefits. Many studies have indicated the antioxidative activity of LAB. Here we review that the effects of lactic acid bacteria to respond to oxidative stress, is connected to oxidative-stress related disease and aging.

  10. Starvation-survival of subsurface bacteria

    International Nuclear Information System (INIS)

    Magill, N.G.

    1988-01-01

    The ability of four subsurface isolates to survive starvation was examined and the results were compared to survival curves obtained for Escherichia coli B and Serratia marcescens. To examine the starvation-survival phenomenon further, several experimental parameters including nutritional history, initial cell density, growth phase, temperature of growth and starvation, and aeration. Nutritional history, initial cell density, and growth phases of the cells had some effect on the ability of these bacteria to survive whereas temperature and limited aeration had no effect under the conditions tested. No conditions were found where E. coli B or Serratia marcescens died rapidly or where less than 10% of the original cell number of viable cells remained. Because the apparent survival of these bacteria may be due to cryptic growth, cross-feeding experiments with 14 C-labeled cells and unlabeled cells were carried out with E. coli B and Pseudomonas Lula V. Leaked extracellular 14 C-compounds were not used for growth or maintenance energy, and were not taken up by either bacterium. Cryptic growth did not occur; the cells were truly starving under the experimental conditions used

  11. Interactive Control System, Intended Strategy, Implemented Strategy dan Emergent Strategy

    OpenAIRE

    Tubagus Ismail; Darjat Sudrajat

    2012-01-01

    The purpose of this study was to examine the relationship between management control system (MCS) and strategy formation processes, namely: intended strategy, emergent strategy and impelemented strategy. The focus of MCS in this study was interactive control system. The study was based on Structural Equation Modeling (SEM) as its multivariate analyses instrument. The samples were upper middle managers of manufacturing company in Banten Province, DKI Jakarta Province and West Java Province. AM...

  12. Identifying the major bacteria causing intramammary infections in individual milk samples of sheep and goats using traditional bacteria culturing and real-time polymerase chain reaction.

    Science.gov (United States)

    Rovai, M; Caja, G; Salama, A A K; Jubert, A; Lázaro, B; Lázaro, M; Leitner, G

    2014-09-01

    Use of DNA-based methods, such as real-time PCR, has increased the sensitivity and shortened the time for bacterial identification, compared with traditional bacteriology; however, results should be interpreted carefully because a positive PCR result does not necessarily mean that an infection exists. One hundred eight lactating dairy ewes (56 Manchega and 52 Lacaune) and 24 Murciano-Granadina dairy goats were used for identifying the main bacteria causing intramammary infections (IMI) using traditional bacterial culturing and real-time PCR and their effects on milk performance. Udder-half milk samples were taken for bacterial culturing and somatic cell count (SCC) 3 times throughout lactation. Intramammary infections were assessed based on bacteria isolated in ≥2 samplings accompanied by increased SCC. Prevalence of subclinical IMI was 42.9% in Manchega and 50.0% in Lacaune ewes and 41.7% in goats, with the estimated milk yield loss being 13.1, 17.9, and 18.0%, respectively. According to bacteriology results, 87% of the identified single bacteria species (with more than 3 colonies/plate) or culture-negative growth were identical throughout samplings, which agreed 98.9% with the PCR results. Nevertheless, the study emphasized that 1 sampling may not be sufficient to determine IMI and, therefore, other inflammatory responses such as increased SCC should be monitored to identify true infections. Moreover, when PCR methodology is used, aseptic and precise milk sampling procedures are key for avoiding false-positive amplifications. In conclusion, both PCR and bacterial culture methods proved to have similar accuracy for identifying infective bacteria in sheep and goats. The final choice will depend on their response time and cost analysis, according to the requirements and farm management strategy. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  13. Identification of Lactic Acid Bacteria and Propionic Acid Bacteria using FTIR Spectroscopy and Artificial Neural Networks

    Directory of Open Access Journals (Sweden)

    Beata Nalepa

    2012-01-01

    Full Text Available In the present study, lactic acid bacteria and propionic acid bacteria have been identified at the genus level with the use of artificial neural networks (ANNs and Fourier transform infrared spectroscopy (FTIR. Bacterial strains of the genera Lactobacillus, Lactococcus, Leuconostoc, Streptococcus and Propionibacterium were analyzed since they deliver health benefits and are routinely used in the food processing industry. The correctness of bacterial identification by ANNs and FTIR was evaluated at two stages. At first stage, ANNs were tested based on the spectra of 66 reference bacterial strains. At second stage, the evaluation involved 286 spectra of bacterial strains isolated from food products, deposited in our laboratory collection, and identified by genus-specific PCR. ANNs were developed based on the spectra and their first derivatives. The most satisfactory results were reported for the probabilistic neural network, which was built using a combination of W5W4W3 spectral ranges. This network correctly identified the genus of 95 % of the lactic acid bacteria and propionic acid bacteria strains analyzed.

  14. HCN Producing Bacteria Enable Sensing Of Non-Bioavailable Hg Species by the Whole Cell Biosensor

    Science.gov (United States)

    Horvat, M.; Rijavec, T.; Koron, N.; Lapanje, A.

    2015-12-01

    Bacteria play an important role in Hg transformation reactions. The production of cyanide (HCN) and other secondary metabolites seems to be key elements involved in these transformations. Current hypotheses link the role of HCN production to growth inhibition of nonHCN producing competitor organisms (role of an antimicrobial agent). Our past investigations showed that HCN production did not correlate with antimicrobial activity and since pK value of HCN is very high (pK = 9,21), it can be expected that most of the produced HCN is removed from the microenvironment. This way, the expected inhibitory concentrations can hardly be reached. Accordingly, we proposed a new concept, where the ability of complexation of transient metals by HCN served as a regulation process for the accessibility of micro-elements. In our study, we focused on the presence of HCN producing bacteria and carried it out in the Hg contaminated environment connected to the Idrija Mercury Mine, Slovenia. We characterised the isolates according to the presence of Hg resistance (HgR), level of HCN production and genetic similarities. In laboratory setups, using our merR whole cell based biosensor, we determined the transformation of low bioavailable Hg0 and HgS forms into bioavailable Hg by these HCN producing bacteria. We observed that HgR strains producing HCN had the highest impact on increased Hg bioavailability. In the proposed ecological strategy HgR HCN producing bacteria increase their competitive edge over non-HgR competitors through the increase of Hg toxicity. Due to their activity, Hg is made available to other organisms as well and thus enters into the ecosystem. Finally, using some of the characteristics of bacteria (e.g. Hg resistance genetic elements), we developed a fully automated sensing approach, combining biosensorics and mechatronics, to measure the bioavailability of Hg in situ.

  15. Isolation of butanol- and isobutanol-tolerant bacteria and physiological characterization of their butanol tolerance.

    Science.gov (United States)

    Kanno, Manabu; Katayama, Taiki; Tamaki, Hideyuki; Mitani, Yasuo; Meng, Xian-Ying; Hori, Tomoyuki; Narihiro, Takashi; Morita, Naoki; Hoshino, Tamotsu; Yumoto, Isao; Kimura, Nobutada; Hanada, Satoshi; Kamagata, Yoichi

    2013-11-01

    Despite their importance as a biofuel production platform, only a very limited number of butanol-tolerant bacteria have been identified thus far. Here, we extensively explored butanol- and isobutanol-tolerant bacteria from various environmental samples. A total of 16 aerobic and anaerobic bacteria that could tolerate greater than 2.0% (vol/vol) butanol and isobutanol were isolated. A 16S rRNA gene sequencing analysis revealed that the isolates were phylogenetically distributed over at least nine genera: Bacillus, Lysinibacillus, Rummeliibacillus, Brevibacillus, Coprothermobacter, Caloribacterium, Enterococcus, Hydrogenoanaerobacterium, and Cellulosimicrobium, within the phyla Firmicutes and Actinobacteria. Ten of the isolates were phylogenetically distinct from previously identified butanol-tolerant bacteria. Two relatively highly butanol-tolerant strains CM4A (aerobe) and GK12 (obligate anaerobe) were characterized further. Both strains changed their membrane fatty acid composition in response to butanol exposure, i.e., CM4A and GK12 exhibited increased saturated and cyclopropane fatty acids (CFAs) and long-chain fatty acids, respectively, which may serve to maintain membrane fluidity. The gene (cfa) encoding CFA synthase was cloned from strain CM4A and expressed in Escherichia coli. The recombinant E. coli showed relatively higher butanol and isobutanol tolerance than E. coli without the cfa gene, suggesting that cfa can confer solvent tolerance. The exposure of strain GK12 to butanol by consecutive passages even enhanced the growth rate, indicating that yet-unknown mechanisms may also contribute to solvent tolerance. Taken together, the results demonstrate that a wide variety of butanol- and isobutanol-tolerant bacteria that can grow in 2.0% butanol exist in the environment and have various strategies to maintain structural integrity against detrimental solvents.

  16. Ruminal tryptophan-utilizing bacteria degrade ergovaline from tall fescue seed extract.

    Science.gov (United States)

    Harlow, B E; Goodman, J P; Lynn, B C; Flythe, M D; Ji, H; Aiken, G E

    2017-02-01

    The objectives of this study were to evaluate degradation of ergovaline in a tall fescue [ (Schreb.) Darbysh.] seed extract by rumen microbiota ex vivo and to identify specific bacteria capable of ergovaline degradation in vitro. Rumen cell suspensions were prepared by harvesting rumen fluid from fistulated wether goats ( = 3), straining, and differential centrifugation. Suspensions were dispensed into anaerobic tubes with added Trypticase with or without extract (∼10 μg kg ergovaline). Suspensions were incubated for 48 h at 39°C. Samples were collected at 0, 24, and 48 h for ergovaline analysis and enumeration of hyper-ammonia producing (HAB) and tryptophan-utilizing bacteria. Ergovaline values were analyzed by repeated measures using the mixed procedure of SAS. Enumeration data were log transformed for statistical analysis. When suspensions were incubated with extract, 11 to 15% of ergovaline disappearance was observed over 48 h ( = 0.02). After 24 h, suspensions with added extract had 10-fold less HAB than controls ( = 0.04), but treatments were similar by 48 h ( = 1.00). However, after 24 h and 48 h, suspensions with extract had 10-fold more tryptophan-utilizing bacteria ( rumen pure cultures ( JB1, B159, HD4, B, F, MD1, SR) were evaluated for the ability to degrade ergovaline in vitro. Pure culture cell suspensions were incubated as described above and samples were taken at 0 and 48 h for ergovaline analysis. Data were analyzed using the ANOVA procedure of SAS. All HAB, including the isolates, tested degraded ergovaline (54 to 75%; bacteria tested did not degrade ergovaline. The results of this study indicate which rumen bacteria may play an important role in ergovaline degradation and that microbiological strategies for controlling their activity could have ramifications for fescue toxicosis and other forms of ergotism in ruminants.

  17. Sulphur bacteria mediated formation of Palaeoproterozoic phosphorites

    Science.gov (United States)

    Joosu, Lauri; Lepland, Aivo; Kirsimäe, Kalle

    2014-05-01

    Modern phosphorite formation is typically associated with high productivity in upwelling areas where apatite (Ca-phosphate) precipitation is mediated by sulphur oxidising bacteria [1]. They inhabit the oxic/anoxic interface within the upper few centimetres of sediment column, accumulating phosphate in their cells under oxic conditions and releasing it rapidly when conditions become anoxic. Sulphur bacteria are known to live in close association with a consortium of anaerobic methane oxidising archaea and syntrophic sulphate-reducing bacteria. Paleoproterozoic, c. 2.0 Ga Zaonega Formation in Karelia, Russia contains several P-rich intervals in the upper part of 1500 m thick succession of organic-rich sedimentary rocks interlayered with mafic tuffs and lavas. Apatite in these P-rich intervals forms impure laminae, lenses and round-oval nodules which diameters typically range from 300 to 1000 μm. Individual apatite particles in P-rich laminae and nodules commonly occur as cylinders that are 1-8 μm long and have diameters of 0.5-4 μm. Cross-sections of best preserved cylindrical apatite particles reveal a thin outer rim whereas the internal parts consist of small anhedral elongated crystallites, intergrown with carbonaceous material. During recrystallization the outer rim thickens towards interior and cylinders may attain hexagonal crystal habit, but their size and shape remains largely unchanged [2]. The sizes of Zaonega nodules are similar to giant sulphide-oxidising bacteria known from modern and ancient settings [3, 4]. Individual apatite cylinders and aggregates have shapes and sizes similar to the methanotrophic archaea that inhabit microbial mats in modern seep/vent areas where they operate in close associations with sulphur-oxidising microbial communities [5]. Seep/vent influence during the Zaonega phosphogenesis is indicated by variable, though positive Eu anomaly, expected in magmatically active sedimentary environment experiencing several lava flows

  18. Revolutionizing membrane protein overexpression in bacteria

    NARCIS (Netherlands)

    Schlegel, Susan; Klepsch, Mirjam; Gialama, Dimitra; Wickstrom, David; Slotboom, Dirk Jan; de Gier, Jan-Willem; Wickström, David

    The bacterium Escherichia coli is the most widely used expression host for overexpression trials of membrane proteins. Usually, different strains, culture conditions and expression regimes are screened for to identify the optimal overexpression strategy. However, yields are often not satisfactory,

  19. Exploring Anopheles gut bacteria for Plasmodium blocking activity

    Science.gov (United States)

    Bahia, Ana C; Dong, Yuemei; Blumberg, Benjamin J; Mlambo, Godfree; Tripathi, Abhai; BenMarzouk-Hidalgo, Omar J; Chandra, Ramesh; Dimopoulos, George

    2014-01-01

    SUMMARY Malaria parasite transmission requires the successful development of Plasmodium gametocytes into flagellated microgametes upon mosquito blood ingestion, and the subsequent fertilization of microgametes and macrogametes for the development of motile zygotes, called ookinetes, which invade and transverse the Anopheles vector mosquito midgut at around 18-36 h after blood ingestion. Within the mosquito midgut, the malaria parasite has to withstand the mosquito's innate immune response and the detrimental effect of its commensal bacterial flora. We have assessed the midgut colonization capacity of 5 gut bacterial isolates from field-derived, and 2 from laboratory colony, mosquitoes and their effect on Plasmodium development in vivo and in vitro, along with their impact on mosquito survival. Some bacterial isolates activated the mosquito's immune system, affected the mosquito's life span, and were capable of blocking Plasmodium development. We have also shown that the ability of these bacteria to inhibit the parasites is likely to involve different mechanisms and factors. A Serratia marcescens isolate was particularly efficient in colonizing the mosquitoes’ gut, compromising mosquito survival, and inhibiting both sexual- and asexual-stage Plasmodium through secreted factors, thereby rendering it a potential candidate for the development of a malaria transmission intervention strategy. PMID:24428613

  20. A metabolic pathway for catabolizing levulinic acid in bacteria

    International Nuclear Information System (INIS)

    Rand, Jacqueline M.; Pisithkul, Tippapha; Clark, Ryan L.; Thiede, Joshua M.; Mehrer, Christopher R.

    2017-01-01

    Microorganisms can catabolize a wide range of organic compounds and therefore have the potential to perform many industrially relevant bioconversions. One barrier to realizing the potential of biorefining strategies lies in our incomplete knowledge of metabolic pathways, including those that can be used to assimilate naturally abundant or easily generated feedstocks. For instance, levulinic acid (LA) is a carbon source that is readily obtainable as a dehydration product of lignocellulosic biomass and can serve as the sole carbon source for some bacteria. Yet, the genetics and structure of LA catabolism have remained unknown. Here, we report the identification and characterization of a seven-gene operon that enables LA catabolism in Pseudomonas putida KT2440. When the pathway was reconstituted with purified proteins, we observed the formation of four acyl-CoA intermediates, including a unique 4-phosphovaleryl-CoA and the previously observed 3-hydroxyvaleryl-CoA product. Using adaptive evolution, we obtained a mutant of Escherichia coli LS5218 with functional deletions of fadE and atoC that was capable of robust growth on LA when it expressed the five enzymes from the P. putida operon. Here, this discovery will enable more efficient use of biomass hydrolysates and metabolic engineering to develop bioconversions using LA as a feedstock.

  1. Bioremediation of copper-contaminated soils by bacteria.

    Science.gov (United States)

    Cornu, Jean-Yves; Huguenot, David; Jézéquel, Karine; Lollier, Marc; Lebeau, Thierry

    2017-02-01

    Although copper (Cu) is an essential micronutrient for all living organisms, it can be toxic at low concentrations. Its beneficial effects are therefore only observed for a narrow range of concentrations. Anthropogenic activities such as fungicide spraying and mining have resulted in the Cu contamination of environmental compartments (soil, water and sediment) at levels sometimes exceeding the toxicity threshold. This review focuses on the bioremediation of copper-contaminated soils. The mechanisms by which microorganisms, and in particular bacteria, can mobilize or immobilize Cu in soils are described and the corresponding bioremediation strategies-of varying levels of maturity-are addressed: (i) bioleaching as a process for the ex situ recovery of Cu from Cu-bearing solids, (ii) bioimmobilization to limit the in situ leaching of Cu into groundwater and (iii) bioaugmentation-assisted phytoextraction as an innovative process for in situ enhancement of Cu removal from soil. For each application, the specific conditions required to achieve the desired effect and the practical methods for control of the microbial processes were specified.

  2. Antibacterial Activities of Endophytic Bacteria Isolated from Taxus brevifolia Against Foodborne Pathogenic Bacteria.

    Science.gov (United States)

    Islam, Nurul; Choi, Jaehyuk; Baek, Kwang-Hyun

    2018-05-01

    Endophytes are a potential source of novel bioactive compounds with medicinal properties. In this study, 41 endophytic bacteria (EB) were isolated from tissues of a medicinally important plant Taxus brevifolia (Pacific yew). The objective was to screen all the EB isolates for their antibacterial effects against five foodborne pathogenic bacteria: Bacillus cereus ATCC10876, Staphylococcus aureus ATCC12600, Listeria monocytogenes ATCC19115, Escherichia coli ATCC43890, and Salmonella Typhimurium ATCC19585. Among the EB isolates, T. brevifolia seed (TbS)-8, T. brevifolia fleshy part of fruit (TbFl)-10, T. brevifolia leaf (TbL)-22, TbS-29, and TbL-34 exerted significant antibacterial activity against the tested foodborne pathogens. Especially TbFl-10 showed the highest antibacterial activity against all the tested bacteria and was identified as Paenibacillus kribbensis (Pk). Furthermore, an ethyl acetate extract of Pk-TbFl-10 possessed antibacterial activities against the tested five foodborne pathogenic bacteria, with zones of inhibition from 15.71 ± 2.85 to 13.01 ± 2.12 mm. Scanning electron microscopy analysis revealed ruptured, lysed, shrunk, and swollen cells of all the tested foodborne pathogens treated with the ethyl acetate extract of Pk-TbFl-10, suggesting that a metabolite(s) of Pk-TbFl-10 penetrates the cell membrane and causes cell lysis leading to cell death. Our results indicate that Pk-TbFl-10 isolated from T. brevifolia can serve as a novel source of natural antibacterial agents against foodborne pathogenic bacteria, with potential applications in the pharmaceutical industry.

  3. [Effects of transgenic Bt + CpTI cotton on rhizosphere bacteria and ammonia oxidizing bacteria population].

    Science.gov (United States)

    Dong, Lianhua; Meng, Ying; Wang, Jing

    2014-03-04

    The effect of transgenic cotton on the rhizosphere bacteria can be important to the risk assessment for the genetically modified crops. We studied the rhizosphere microbial community with cultivating genetically modified cotton. The effects of transgenic Bt + CpTI Cotton (SGK321) and its receptor cotton (SY321) on rhizosphere total bacteria and ammonia oxidizing bacteria population size were studied by using droplet digital PCR. We collected rhizosphere soil before cotton planting and along with the cotton growth stage (squaring stage, flowering stage, belling stage and boll opening stage). There was no significant change on the total bacterial population between the transgenic cotton and the receptor cotton along with the growth stage. However, the abundance of ammonia oxidizing bacteria (AOB) in both type of cottons showed significant difference between different growth stages, and the variation tendency was different. In squaring stage, the numbers of AOB in rhizosphere of SY321 and SGK321 increased 4 and 2 times, respectively. In flowering stage, AOB number in rhizosphere of SY321 significantly decreased to be 5.96 x 10(5) copies/g dry soil, however, that of SGK321 increased to be 1.25 x 10(6) copies/g dry soil. In belling stage, AOB number of SY321 greatly increased to be 1.49 x 10(6) copies/g dry soil, but no significant change was observed for AOB number of SGK321. In boll opening stage, both AOB number of SY321 and SGK321 clearly decreased and they were significantly different from each other. Compared to the non-genetically modified cotton, the change in abundance of ammonia oxidizing bacteria was slightly smooth in the transgenic cotton. Not only the cotton growth stage but also the cotton type caused this difference. The transgenic cotton can slow down the speed of ammonia transformation through impacting the number of AOB, which is advantageous for plant growth.

  4. Reactivity of the Bacteria-Water Interface: Linking Nutrient Availability to Bacteria-Metal Interactions

    Science.gov (United States)

    Fowle, D. A.; Daughney, C. J.; Riley, J. L.

    2002-12-01

    Identifying and quantifying the controls on metal mobilities in geologic systems is critical in order to understand processes such as global element cycling, metal transport in near-surface water-rock systems, sedimentary diagenesis, and mineral formation. Bacteria are ubiquitous in near-surface water-rock systems, and numerous laboratory and field studies have demonstrated that bacteria can facilitate the formation and dissolution of minerals, and enhance or inhibit contaminant transport. However, despite the growing evidence that bacteria play a key role in many geologic processes in low temperature systems, our understanding of the influence of the local nutrient dynamics of the system of interest on bacteria-metal interactions is limited. Here we present data demonstrating the effectiveness of coupling laboratory experiments with geochemical modeling to isolate the effect of nutrient availability on bacterially mediated proton and metal adsorption reactions. Experimental studies of metal-bacteria interactions were conducted in batch reactors as a function of pH, and solid-solute interactions after growth in a variety of defined and undefined media. Media nutrient composition (C,N,P) was quantified before and after harvesting the cells. Surface complexation models (SCM) for the adsorption reactions were developed by combining sorption data with the results of acid-base titrations, and in some cases zeta potential titrations of the bacterial surface. Our results indicate a clear change in both buffering potential and metal binding capacity of the cell walls of Bacillus subtilis as a function of initial media conditions. Combining current studies with our past studies on the effects of growth phase and others work on temperature dependence on metal adsorption we hope to develop a holistic surface complexation model for quantifying bacterial effects on metal mass transfer in many geologic systems.

  5. Bacterial strategies of resistance to antimicrobial peptides.

    Science.gov (United States)

    Joo, Hwang-Soo; Fu, Chih-Iung; Otto, Michael

    2016-05-26

    Antimicrobial peptides (AMPs) are a key component of the host's innate immune system, targeting invasive and colonizing bacteria. For successful survival and colonization of the host, bacteria have a series of mechanisms to interfere with AMP activity, and AMP resistance is intimately connected with the virulence potential of bacterial pathogens. In particular, because AMPs are considered as potential novel antimicrobial drugs, it is vital to understand bacterial AMP resistance mechanisms. This review gives a comparative overview of Gram-positive and Gram-negative bacterial strategies of resistance to various AMPs, such as repulsion or sequestration by bacterial surface structures, alteration of membrane charge or fluidity, degradation and removal by efflux pumps.This article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'. © 2016 The Author(s).

  6. Discovery, research, and development of new antibiotics: the WHO priority list of antibiotic-resistant bacteria and tuberculosis.

    Science.gov (United States)

    Tacconelli, Evelina; Carrara, Elena; Savoldi, Alessia; Harbarth, Stephan; Mendelson, Marc; Monnet, Dominique L; Pulcini, Céline; Kahlmeter, Gunnar; Kluytmans, Jan; Carmeli, Yehuda; Ouellette, Marc; Outterson, Kevin; Patel, Jean; Cavaleri, Marco; Cox, Edward M; Houchens, Chris R; Grayson, M Lindsay; Hansen, Paul; Singh, Nalini; Theuretzbacher, Ursula; Magrini, Nicola

    2018-03-01

    The spread of antibiotic-resistant bacteria poses a substantial threat to morbidity and mortality worldwide. Due to its large public health and societal implications, multidrug-resistant tuberculosis has been long regarded by WHO as a global priority for investment in new drugs. In 2016, WHO was requested by member states to create a priority list of other antibiotic-resistant bacteria to support research and development of effective drugs. We used a multicriteria decision analysis method to prioritise antibiotic-resistant bacteria; this method involved the identification of relevant criteria to assess priority against which each antibiotic-resistant bacterium was rated. The final priority ranking of the antibiotic-resistant bacteria was established after a preference-based survey was used to obtain expert weighting of criteria. We selected 20 bacterial species with 25 patterns of acquired resistance and ten criteria to assess priority: mortality, health-care burden, community burden, prevalence of resistance, 10-year trend of resistance, transmissibility, preventability in the community setting, preventability in the health-care setting, treatability, and pipeline. We stratified the priority list into three tiers (critical, high, and medium priority), using the 33rd percentile of the bacterium's total scores as the cutoff. Critical-priority bacteria included carbapenem-resistant Acinetobacter baumannii and Pseudomonas aeruginosa, and carbapenem-resistant and third-generation cephalosporin-resistant Enterobacteriaceae. The highest ranked Gram-positive bacteria (high priority) were vancomycin-resistant Enterococcus faecium and meticillin-resistant Staphylococcus aureus. Of the bacteria typically responsible for community-acquired infections, clarithromycin-resistant Helicobacter pylori, and fluoroquinolone-resistant Campylobacter spp, Neisseria gonorrhoeae, and Salmonella typhi were included in the high-priority tier. Future development strategies should focus on

  7. Reducing gas content of coal deposits by means of bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Godlewska-Lipowa, A A; Kozlowski, B

    1981-07-01

    This paper discusses the results of experiments carried out in Poland under laboratory conditions on efficiency of methane control using bacteria from Methanosarcina and Methanomonas groups. Malashenko and Whittenburry culture mediums were used. Bacteria growth in an atmosphere of air and methane (48.2%, 8.6% and 5.21%) was observed. Temperature ranged from 19 to 20 C. Investigations show that the bacteria are characterized by high oxidation activity. Depending on methane concentration in the air the bacteria consume from 75% to 100% of methane during biosynthesis. The bacteria reduce methane and oxygen content and increase carbon dioxide content in the air. Using bacteria methane concentration in the air was reduced from 48.2% to 12.3%, from 8.6% to 0.0% and from 5.21% to 0.01%. (7 refs.) (In Polish)

  8. Influence of irradiation of bacteria on their thermoresistance

    International Nuclear Information System (INIS)

    Szulc, M.; Stefaniakowa, A.; Tropilo, J.; Stanczak, B.; Peconek, J.; Mierzewska, H.; Bielecka, J.

    1979-01-01

    The influence of x-radiation on thermoresistance of bacteria was determined. The studies were carried out on: E. coli, Pr. vulgaris, S. typhimurium, Staph. aureus and Str. faecalis. The bacteria were irradiated in PBS (physiological buffer solution) and in broth (containing about 1% of protein) with x-rays at radium absorbed doses of 100, 1000, 5000 and 10 000, which was followed immediately by heating at temperatures causing death of part of the bacteria. The results obtained indicate that irradiation of bacteria with small x-ray doses distinctly decreases their thermoresistance. Synergetic action of irradiation and heating of bacteria was observed, increasing with increased irradiation dose. The greatest changes of thermoresistance occurred with Pr. vulgaris, the smallest with S. typhimurium. Thermoresistance of bacteria decreased more strongly on their irradiation in protein-free medium (PBS). (author)

  9. Biotechnological applications of acetic acid bacteria.

    Science.gov (United States)

    Raspor, Peter; Goranovic, Dusan

    2008-01-01

    The acetic acid bacteria (AAB) have important roles in food and beverage production, as well as in the bioproduction of industrial chemicals. In recent years, there have been major advances in understanding their taxonomy, molecular biology, and physiology, and in methods for their isolation and identification. AAB are obligate aerobes that oxidize sugars, sugar alcohols, and ethanol with the production of acetic acid as the major end product. This special type of metabolism differentiates them from all other bacteria. Recently, the AAB taxonomy has been strongly rearranged as new techniques using 16S rRNA sequence analysis have been introduced. Currently, the AAB are classified in ten genera in the family Acetobacteriaceae. AAB can not only play a positive role in the production of selected foods and beverages, but they can also spoil other foods and beverages. AAB occur in sugar- and alcohol-enriched environments. The difficulty of cultivation of AAB on semisolid media in the past resulted in poor knowledge of the species present in industrial processes. The first step of acetic acid production is the conversion of ethanol from a carbohydrate carried out by yeasts, and the second step is the oxidation of ethanol to acetic acid carried out by AAB. Vinegar is traditionally the product of acetous fermentation of natural alcoholic substrates. Depending on the substrate, vinegars can be classified as fruit, starch, or spirit substrate vinegars. Although a variety of bacteria can produce acetic acid, mostly members of Acetobacter, Gluconacetobacter, and Gluconobacter are used commercially. Industrial vinegar manufacturing processes fall into three main categories: slow processes, quick processes, and submerged processes. AAB also play an important role in cocoa production, which represents a significant means of income for some countries. Microbial cellulose, produced by AAB, possesses some excellent physical properties and has potential for many applications. Other

  10. Transmission of Nephridial Bacteria of the Earthworm Eisenia fetida

    OpenAIRE

    Davidson, Seana K.; Stahl, David A.

    2006-01-01

    The lumbricid earthworms (annelid family Lumbricidae) harbor gram-negative bacteria in their excretory organs, the nephridia. Comparative 16S rRNA gene sequencing of bacteria associated with the nephridia of several earthworm species has shown that each species of worm harbors a distinct bacterial species and that the bacteria from different species form a monophyletic cluster within the genus Acidovorax, suggesting that there is a specific association resulting from radiation from a common b...

  11. Heme and menaquinone induced electron transport in lactic acid bacteria

    OpenAIRE

    Brooijmans, Rob; Smit, Bart; Santos, Filipe; van Riel, Jan; de Vos, Willem M; Hugenholtz, Jeroen

    2009-01-01

    Abstract Background For some lactic acid bacteria higher biomass production as a result of aerobic respiration has been reported upon supplementation with heme and menaquinone. In this report, we have studied a large number of species among lactic acid bacteria for the existence of this trait. Results Heme- (and menaquinone) stimulated aerobic growth was observed for several species and genera of lactic acid bacteria. These include Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacill...

  12. Carbon Capture and Storage (CCS): Risk assessment focused on marine bacteria.

    Science.gov (United States)

    Borrero-Santiago, A R; DelValls, T A; Riba, I

    2016-09-01

    Carbon capture and storage (CCS) is one of the options to mitigate the negative effects of the climate change. However, this strategy may have associated some risks such as CO2 leakages due to an escape from the reservoir. In this context, marine bacteria have been underestimated. In order to figure out the gaps and the lack of knowledge, this work summarizes different studies related to the potential effects on the marine bacteria associated with an acidification caused by a CO2 leak from CSS. An improved integrated model for risk assessment is suggested as a tool based on the rapid responses of bacterial community. Moreover, this contribution proposes a strategy for laboratory protocols using Pseudomona stanieri (CECT7202) as a case of study and analyzes the response of the strain under different CO2 conditions. Results showed significant differences (p≤0.05) under six diluted enriched medium and differences about the days in the exponential growth phase. Dilution 1:10 (Marine Broth 2216 with seawater) was selected as an appropriate growth medium for CO2 toxicity test in batch cultures. This work provide an essential and a complete tool to understand and develop a management strategy to improve future works related to possible effects produced by potential CO2 leaks. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Biodegradation of endosulfan by mixed bacteria culture strains of ...

    African Journals Online (AJOL)

    Biodegradation of endosulfan by mixed bacteria culture strains of Pseudomonas aeruginosa and Staphylococcus aureus. Nsidibeabasi Calvin Nwokem, Calvin Onyedika Nwokem, Casmir Emmanuel Gimba, Beatrice Nkiruka Iwuala ...

  14. Effect of radiation on activity of sulphate reducing bacteria

    International Nuclear Information System (INIS)

    Agaev, N.M.; Smorodin, A.E.; Gusejnov, M.M.

    1985-01-01

    The effect of γ-radiation on activity of sulphate reducing bacteria has been studied. Concentration of biogenic hydrogen, generated in the medium, is the main criterion, characterizing corrosion activity of the bacteria studied. The developed method of suppression of active development of sulfate reducing bacteria considerably reduces, and at lethal doses of γ-radiation eliminates altogether the bacteria activity and formation of the main corrosion agent-hydrogen sulphide-in the medium and that, in its turn, liquidates hydrogen sulphide corrosion

  15. Characterization of Bacteria Associated with Pinewood Nematode Bursaphelenchus xylophilus

    Science.gov (United States)

    Vicente, Claudia S. L.; Nascimento, Francisco; Espada, Margarida; Barbosa, Pedro; Mota, Manuel; Glick, Bernard R.; Oliveira, Solange

    2012-01-01

    Pine wilt disease (PWD) is a complex disease integrating three major agents: the pathogenic agent, the pinewood nematode Bursaphelenchus xylophilus; the insect-vector Monochamus spp.; and the host pine tree, Pinus sp. Since the early 80's, the notion that another pathogenic agent, namely bacteria, may play a role in PWD has been gaining traction, however the role of bacteria in PWD is still unknown. The present work supports the possibility that some B. xylophilus-associated bacteria may play a significant role in the development of this disease. This is inferred as a consequence of: (i) the phenotypic characterization of a collection of 35 isolates of B. xylophilus-associated bacteria, in different tests broadly used to test plant pathogenic and plant growth promoting bacteria, and (ii) greenhouse experiments that infer the pathogenicity of these bacteria in maritime pine, Pinus pinaster. The results illustrate the presence of a heterogeneous microbial community associated with B. xylophilus and the traits exhibited by at least, some of these bacteria, appear to be related to PWD symptoms. The inoculation of four specific B. xylophilus-associated bacteria isolates in P. pinaster seedlings resulted in the development of some PWD symptoms suggesting that these bacteria likely play an active role with B. xylophilus in PWD. PMID:23091599

  16. Characterization of carbofuran-degrading bacteria isolated from ...

    African Journals Online (AJOL)

    Workstation

    Key words: Pesticides, carbofuran, methomyl, biodegradation, bacteria. INTRODUCTION .... polymerase chain reaction (PCR) amplification and partial sequence analysis of ..... Beutel KK (1986). Chlorinated hydrocarbon, In W. Gerhartz (ed.),.

  17. Investigation of IR absorption spectra of oral cavity bacteria

    Science.gov (United States)

    Belikov, Andrei V.; Altshuler, Gregory B.; Moroz, Boris T.; Pavlovskaya, Irina V.

    1996-12-01

    The results of comparative investigation for IR and visual absorption spectra of oral cavity bacteria are represented by this paper. There are also shown the main differences in absorption spectra of such pure bacteria cultures as : E- coli, Candida, Staph, Epidermidis, and absorption spectra of bacteria colonies cultured in tooth root canals suspected to harbour several endodontical problems. The results of experimental research targeted to investigate an effect of such combined YAG:Nd and YAG:Cr; Tm; Ho laser parameters like: wavelength, energy density, average power and etc., to oral cavity bacteria deactivation are given finally.

  18. Solar-panel and parasol strategies shape the proteorhodopsin distribution pattern in marine Flavobacteriia.

    Science.gov (United States)

    Kumagai, Yohei; Yoshizawa, Susumu; Nakajima, Yu; Watanabe, Mai; Fukunaga, Tsukasa; Ogura, Yoshitoshi; Hayashi, Tetsuya; Oshima, Kenshiro; Hattori, Masahira; Ikeuchi, Masahiko; Kogure, Kazuhiro; DeLong, Edward F; Iwasaki, Wataru

    2018-05-01

    Proteorhodopsin (PR) is a light-driven proton pump that is found in diverse bacteria and archaea species, and is widespread in marine microbial ecosystems. To date, many studies have suggested the advantage of PR for microorganisms in sunlit environments. The ecophysiological significance of PR is still not fully understood however, including the drivers of PR gene gain, retention, and loss in different marine microbial species. To explore this question we sequenced 21 marine Flavobacteriia genomes of polyphyletic origin, which encompassed both PR-possessing as well as PR-lacking strains. Here, we show that the possession or alternatively the lack of PR genes reflects one of two fundamental adaptive strategies in marine bacteria. Specifically, while PR-possessing bacteria utilize light energy ("solar-panel strategy"), PR-lacking bacteria exclusively possess UV-screening pigment synthesis genes to avoid UV damage and would adapt to microaerobic environment ("parasol strategy"), which also helps explain why PR-possessing bacteria have smaller genomes than those of PR-lacking bacteria. Collectively, our results highlight the different strategies of dealing with light, DNA repair, and oxygen availability that relate to the presence or absence of PR phototrophy.

  19. Physical mode of bacteria and virus coevolution

    Science.gov (United States)

    Han, Pu; Niestemski, Liang; Deem, Michael

    2013-03-01

    Single-cell hosts such as bacteria or archaea possess an adaptive, heritable immune system that protects them from viral invasion. This system, known as the CRISPR-Cas system, allows the host to recognize and incorporate short foreign DNA or RNA sequences from viruses or plasmids. The sequences form what are called ``spacers'' in the CRISPR. Spacers in the CRISPR loci provide a record of the host and predator coevolution history. We develop a physical model to study the dynamics of this coevolution due to immune pressure. Hosts and viruses reproduce, die, and evolve due to viral infection pressure, host immune pressure, and mutation. We will discuss the differing effects of point mutation and recombination on CRISPR evolution. We will also discuss the effect of different spacer deletion mechanisms. We will describe population structure of hosts and viruses, how spacer diversity depends on position within CRISPR, and match of the CRISPR spacers to the virus population.

  20. Streptomyces bacteria as potential probiotics in aquaculture

    Directory of Open Access Journals (Sweden)

    Tan Loh eTeng Hern

    2016-02-01

    Full Text Available In response to the increased seafood demand from the ever-going human population, aquaculture has become the fastest growing animal food-producing sector. However, the indiscriminate use of antibiotics as a biological control agents for fish pathogens has led to the emergence of antibiotic resistance bacteria. Probiotics are defined as living microbial supplement that exert beneficial effects on hosts as well as improvement of environmental parameters. Probiotics have been proven to be effective in improving the growth, survival and health status of the aquatic livestock. This review aims to highlight the genus Streptomyces can be a good candidate for probiotics in aquaculture. Studies showed that the feed supplemented with Streptomyces could protect fish and shrimp from pathogens as well as increase the growth of the aquatic organisms. Furthermore, the limitations of Streptomyces as probiotics in aquaculture is also highlighted and solutions are discussed to these limitations.

  1. [Antimicrobial susceptibility testing of anaerobic bacteria].

    Science.gov (United States)

    García-Sánchez, José E; García-Sánchez, Enrique; García-García, María Inmaculada

    2014-02-01

    The anaerobic bacteria resistance to antibiotics is increasing, and even has appeared against the most active of those, like metronidazol and carbapenems. This fact forces to make and periodical sensibility tests -at least in the most aggressive and virulent species, in cases that they are isolated from life locations and in the absence of therapeutic response- to check the local sensibility and to establish suitable empiric therapies, all based on multicentric studies carried out in order to this or well to check the activity of new antibiotics. For the laboratory routine, the easiest sensibility method is the E-test/MIC evaluator. Another alternative is microdilution, that's only normalized for Bacteroides. There are preliminary facts that allow the use of disc diffusion method in some species of Bacteroides and Clostridium. For the temporal and multicentric studies, the procedure is dilution in agar plate, the reference method. Copyright © 2014 Elsevier España, S.L. All rights reserved.

  2. REGEN: Ancestral Genome Reconstruction for Bacteria

    Directory of Open Access Journals (Sweden)

    João C. Setubal

    2012-07-01

    Full Text Available Ancestral genome reconstruction can be understood as a phylogenetic study with more details than a traditional phylogenetic tree reconstruction. We present a new computational system called REGEN for ancestral bacterial genome reconstruction at both the gene and replicon levels. REGEN reconstructs gene content, contiguous gene runs, and replicon structure for each ancestral genome. Along each branch of the phylogenetic tree, REGEN infers evolutionary events, including gene creation and deletion and replicon fission and fusion. The reconstruction can be performed by either a maximum parsimony or a maximum likelihood method. Gene content reconstruction is based on the concept of neighboring gene pairs. REGEN was designed to be used with any set of genomes that are sufficiently related, which will usually be the case for bacteria within the same taxonomic order. We evaluated REGEN using simulated genomes and genomes in the Rhizobiales order.

  3. Synthesis of Metal Nanoparticles by Bacteria

    Directory of Open Access Journals (Sweden)

    Fikriye Alev Akçay

    2018-04-01

    Full Text Available Metal particles reduced to nano size by nanotechnological methods are confronted in many different fields such as biomedical and physicochemical, pharmaceutical, electric-electronic, automotive and food industries. Nanoparticles can be produced using chemical, physical and biological methods, of which chemical processes are in common use. However, physical and chemical methods are not environmentally friendly and economical because they require the use of high temperature, high pressure and toxic chemicals. For this reason, interest in the production of metal nanoparticles by biological methods, also called green technology, an environmentally friendly and sustainable approach, has increased in recent years. With some plant extracts and intracellular and extracellular secretions of microorganisms, some reduction reactions take place and metal nanoparticles are produced. Bacteria have been actively involved in nanotechnology in recent years due to their diversity in nature, their ease of isolation, and ease of nanoparticle synthesis. In this article, production and application of metal nanoparticles by using bacterial methods have been reviewed.

  4. Laser-induced fluorescence imaging of bacteria

    Science.gov (United States)

    Hilton, Peter J.

    1998-12-01

    This paper outlines a method for optically detecting bacteria on various backgrounds, such as meat, by imaging their laser induced auto-fluorescence response. This method can potentially operate in real-time, which is many times faster than current bacterial detection methods, which require culturing of bacterial samples. This paper describes the imaging technique employed whereby a laser spot is scanned across an object while capturing, filtering, and digitizing the returned light. Preliminary results of the bacterial auto-fluorescence are reported and plans for future research are discussed. The results to date are encouraging with six of the eight bacterial strains investigated exhibiting auto-fluorescence when excited at 488 nm. Discrimination of these bacterial strains against red meat is shown and techniques for reducing background fluorescence discussed.

  5. REGEN: Ancestral Genome Reconstruction for Bacteria.

    Science.gov (United States)

    Yang, Kuan; Heath, Lenwood S; Setubal, João C

    2012-07-18

    Ancestral genome reconstruction can be understood as a phylogenetic study with more details than a traditional phylogenetic tree reconstruction. We present a new computational system called REGEN for ancestral bacterial genome reconstruction at both the gene and replicon levels. REGEN reconstructs gene content, contiguous gene runs, and replicon structure for each ancestral genome. Along each branch of the phylogenetic tree, REGEN infers evolutionary events, including gene creation and deletion and replicon fission and fusion. The reconstruction can be performed by either a maximum parsimony or a maximum likelihood method. Gene content reconstruction is based on the concept of neighboring gene pairs. REGEN was designed to be used with any set of genomes that are sufficiently related, which will usually be the case for bacteria within the same taxonomic order. We evaluated REGEN using simulated genomes and genomes in the Rhizobiales order.

  6. Degradation of multiwall carbon nanotubes by bacteria

    International Nuclear Information System (INIS)

    Zhang, Liwen; Petersen, Elijah J.; Habteselassie, Mussie Y.; Mao, Liang; Huang, Qingguo

    2013-01-01

    Understanding the environmental transformation of multiwall carbon nanotubes (MWCNTs) is important to their life cycle assessment and potential environmental impacts. We report that a bacterial community is capable of degrading 14 C-labeled MWCNTs into 14 CO 2 in the presence of an external carbon source via co-metabolism. Multiple intermediate products were detected, and genotypic characterization revealed three possible microbial degraders: Burkholderia kururiensis, Delftia acidovorans, and Stenotrophomonas maltophilia. This result suggests that microbe/MWCNTs interaction may impact the long-term fate of MWCNTs. Highlights: •Mineralization of MWCNTs by a bacterial community was observed. •The mineralization required an external carbon source. •Multiple intermediate products were identified in the MWCNT degrading culture. •Three bacterial species were found likely responsible for MWCNT degradation. -- The 14 C-labeled multiwall carbon nanotubes can be degraded to 14 CO 2 and other byproducts by a bacteria community under natural conditions

  7. Phosphate Solubilizing Bacteria Adaptive to Vinasse

    Directory of Open Access Journals (Sweden)

    Kahar Muzakhar

    2015-06-01

    Full Text Available Microorganisms identified as phosphate solubilizing bacteria (PSB adaptive to vinasse were successfully screened from sugarcane soil from an agriculatural estate in Jatiroto. By conducting a screening on Pikovskaya’s agar medium (PAM, we found that five different isolates were detected as PSB (pvk-5a, pvk-5b, pvk-6b, pvk-7a, and pvk-8a. Of the five isolates only three could be grown and were found to be adaptive to vinasse based medium without any nutrients added (pvk-5a, pvk-5b and pvk-7a. The three isolates were characterized as coccus and Gram negative with no endospores detected. We suggest that these three isolates can be used as biofertilizer agent to support organic farming.

  8. Cultivable bacteria populations associated with leaves of banana and plantain plants and their antagonistic activity against Mycosphaerella fijiensis.

    Science.gov (United States)

    Ceballos, Isabel; Mosquera, Sandra; Angulo, Mónica; Mira, John J; Argel, Luz Edith; Uribe-Velez, Daniel; Romero-Tabarez, Magally; Orduz-Peralta, Sergio; Villegas, Valeska

    2012-10-01

    Mycosphaerella fijiensis is the etiological agent of Black Sigatoka, a fungal disease that affects production of banana and plantain crops in tropical regions. The sizes of cultivable epiphytic and endophytic bacterial populations, aerobic endospore forming bacteria (AEFB), and antagonist bacteria against M. fijiensis isolated from three Musa spp. cultivars from Urabá (Colombia) were studied, in order to find a suitable screening strategy to isolate antagonistic bacteria. Most of the variability found in the epiphytic and endophytic bacterial community sizes among fruit trees was explained by the cultivar differences. We found population sizes ranging from 1.25 × 10(3) to 9.64 × 10(5) CFU/g of fresh leaf and found that 44 % of total cultivable bacteria belong to the AEFB group. We isolated 648 AEFB from three different cultivars and assessed their antagonistic activity against M. fijiensis using the cell-free supernatant obtained from bacterial liquid cultures in three different in vitro assays. Five percent of those bacteria showed higher percent inhibition than the positive control Bacillus subtilis UA321 has (percent inhibition = 84 ± 5) in the screening phase. Therefore, they were selected as antagonistic bacteria against the pathogen. The strains with the highest percentage of antagonism were found in older leaves for the three cultivars, given support to recommend this group of leaves for future samplings. Some of these isolated bacteria affected the mycelium and ascospores morphology of the fungus. They also presented in vitro characteristics related to a successful colonization of the phylloplane such as indolic compounds, surfactant production, and biofilm formation, which makes them possible, potential candidates as biological control agents.

  9. Enumeration of petroleum hydrocarbon utilizing bacteria

    International Nuclear Information System (INIS)

    Mukherjee, S.; Barot, M.; Levine, A.D.

    1996-01-01

    In-situ biological treatment is one among a number of emerging technologies that may be applied to the remediation of contaminated soils and groundwater. In 1985, a surface spill of 1,500 gallons of dielectric transformer oil at the Sandia National Laboratories (HERMES II facility) resulted in contamination of soil up to depths of 160 feet. The extent of contamination and site characteristics favored the application of in-situ bioremediation as a potential remedial technology. The purpose of this research was to enumerate indigenous microbial populations capable of degrading petroleum hydrocarbons. Microbial enumeration and characterization methods suitably adapted for hydrocarbon utilizing bacteria were used as an indicator of the presence of viable microbial consortia in excavated oil samples with hydrocarbon (TPH) concentrations ranging from 300 to 26,850 ppm. Microbial activity was quantified by direct and streak plating soil samples on silica gel media. Effects of toxicity and temperature were studied using batch cultures of hydrocarbon utilizing bacteria (selectively isolated in an enrichment medium), at temperatures of 20 and 35 C. It was concluded from this study that it is possible to isolate native microorganisms from contaminated soils from depths of 60 to 160 feet, and with oil concentration ranging from 300 to 26,850 ppm. About 62% of the microorganisms isolated form the contaminated soil were capable of using contaminant oil as a substrate for growth and metabolism under aerobic conditions. Growth rates were observed to be 50% higher for the highest contaminant concentration at 20 C. Resistance to toxicity to contaminant oil was also observed to be greater at 20 C than at 35 C

  10. Diversity of rumen bacteria in canadian cervids.

    Directory of Open Access Journals (Sweden)

    Robert J Gruninger

    Full Text Available Interest in the bacteria responsible for the breakdown of lignocellulosic feedstuffs within the rumen has increased due to their potential utility in industrial applications. To date, most studies have focused on bacteria from domesticated ruminants. We have expanded the knowledge of the microbial ecology of ruminants by examining the bacterial populations found in the rumen of non-domesticated ruminants found in Canada. Next-generation sequencing of 16S rDNA was employed to characterize the liquid and solid-associated bacterial communities in the rumen of elk (Cervus canadensis, and white tailed deer (Odocoileus virginianus. Despite variability in the microbial populations between animals, principle component and weighted UniFrac analysis indicated that bacterial communities in the rumen of elk and white tail deer are distinct. Populations clustered according to individual host animal and not the association with liquid or solid phase of the rumen contents. In all instances, Bacteroidetes and Firmicutes were the dominant bacterial phyla, although the relative abundance of these differed among ruminant species and between phases of rumen digesta, respectively. In the elk samples Bacteroidetes were more predominant in the liquid phase whereas Firmicutes was the most prevalent phyla in the solid digesta (P = 1×10(-5. There were also statistically significant differences in the abundance of OTUs classified as Fibrobacteres (P = 5×10(-3 and Spirochaetes (P = 3×10(-4 in the solid digesta of the elk samples. We identified a number of OTUs that were classified as phylotypes not previously observed in the rumen environment. Our results suggest that although the bacterial diversity in wild North American ruminants shows overall similarities to domesticated ruminants, we observed a number of OTUs not previously described. Previous studies primarily focusing on domesticated ruminants do not fully represent the microbial diversity of the

  11. Effects of interactions of auxin-producing bacteria and bacterial-feeding nematodes on regulation of peanut growths.

    Science.gov (United States)

    Xu, Li; Xu, Wensi; Jiang, Ying; Hu, Feng; Li, Huixin

    2015-01-01

    The influences of an IAA (indole-3-acetic acid)-producing bacterium (Bacillus megaterium) and two bacterial-feeding nematodes (Cephalobus sp. or Mesorhabditis sp.) on the growth of peanut (Arachis hypogaea L. cv. Haihua 1) after various durations of time were investigated in natural soils. The addition of bacteria and nematodes and incubation time all significantly affected plant growth, plant root growth, plant nutrient concentrations, soil nutrient concentrations, soil microorganisms and soil auxin concentration. The addition of nematodes caused greater increases in these indices than those of bacteria, while the addition of the combination of bacteria and nematodes caused further increases. After 42-day growth, the increases in soil respiration differed between the additions of two kinds of nematodes because of differences in their life strategies. The effects of the bacteria and nematodes on the nutrient and hormone concentrations were responsible for the increases in plant growth. These results indicate the potential for promoting plant growth via the addition of nematodes and bacteria to soil.

  12. Inhibition of various gram-positive and gram-negative bacteria growth on selenium nanoparticle coated paper towels.

    Science.gov (United States)

    Wang, Qi; Larese-Casanova, Philip; Webster, Thomas J

    2015-01-01

    There are wide spread bacterial contamination issues on various paper products, such as paper towels hanging in sink splash zones or those used to clean surfaces, filter papers used in water and air purifying systems, and wrappings used in the food industry; such contamination may lead to the potential spread of bacteria and consequent severe health concerns. In this study, selenium nanoparticles were coated on normal paper towel surfaces through a quick precipitation method, introducing antibacterial properties to the paper towels in a healthy way. Their effectiveness at preventing biofilm formation was tested in bacterial assays involving Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus epidermidis. The results showed significant and continuous bacteria inhibition with about a 90% reduction from 24 to 72 hours for gram-positive bacteria including S. aureus and S. epidermidis. The selenium coated paper towels also showed significant inhibition of gram-negative bacteria like P. aeruginosa and E. coli growth at about 57% and 84%, respectively, after 72 hours of treatment. Therefore, this study established a promising selenium-based antibacterial strategy to prevent bacterial growth on paper products, which may lead to the avoidance of bacteria spreading and consequent severe health concerns.

  13. Effect of air pollution on the total bacteria and pathogenic bacteria in different sizes of particulate matter.

    Science.gov (United States)

    Liu, Huan; Zhang, Xu; Zhang, Hao; Yao, Xiangwu; Zhou, Meng; Wang, Jiaqi; He, Zhanfei; Zhang, Huihui; Lou, Liping; Mao, Weihua; Zheng, Ping; Hu, Baolan

    2018-02-01

    In recent years, air pollution events have occurred frequently in China during the winter. Most studies have focused on the physical and chemical composition of polluted air. Some studies have examined the bacterial bioaerosols both indoors and outdoors. But few studies have focused on the relationship between air pollution and bacteria, especially pathogenic bacteria. Airborne PM samples with different diameters and different air quality index values were collected in Hangzhou, China from December 2014 to January 2015. High-throughput sequencing of 16S rRNA was used to categorize the airborne bacteria. Based on the NCBI database, the "Human Pathogen Database" was established, which is related to human health. Among all the PM samples, the diversity and concentration of total bacteria were lowest in the moderately or heavily polluted air. However, in the PM2.5 and PM10 samples, the relative abundances of pathogenic bacteria were highest in the heavily and moderately polluted air respectively. Considering the PM samples with different particle sizes, the diversities of total bacteria and the proportion of pathogenic bacteria in the PM10 samples were different from those in the PM2.5 and TSP samples. The composition of PM samples with different sizes range may be responsible for the variances. The relative humidity, carbon monoxide and ozone concentrations were the main factors, which affected the diversity of total bacteria and the proportion of pathogenic bacteria. Among the different environmental samples, the compositions of the total bacteria were very similar in all the airborne PM samples, but different from those in the water, surface soil, and ground dust samples. Which may be attributed to that the long-distance transport of the airflow may influence the composition of the airborne bacteria. This study of the pathogenic bacteria in airborne PM samples can provide a reference for environmental and public health researchers. Copyright © 2017 Elsevier Ltd

  14. Cadmium resistance of endophytic bacteria and rizosféricas bacteria isolated from Oriza sativa in Colombia

    Directory of Open Access Journals (Sweden)

    Nataly Ayubb T

    2017-12-01

    Full Text Available The present study had as objective to evaluate in vitro the resistance of endophytic bacteria and rizospheric bacteria to different concentrations of Cadmium.This bacteria were isolated fron different tissues of commercial rice varieties and from bacteria isolated from the rhizosphere in rice plantations of the Nechí (Antioquía and Achí (Bolivar.  Plant growth promotion was evaluated in vitro by nitrogen fixation, phosphate solubilization and siderophores production of endophytic bacteria. Of each tissue isolated from rice plants was carried out isolation in culture medium for endophytic bacteria, and the soil samples were serially diluted in peptone water. Each sample was determined the population density by counting in CFU / g of tissue and morphotypes were separated by shape, color, size and appearance in culture media. Significant differences were observed for density population of bacteria with respect to tissue, with higher values in root (4x1011 g/root, followed of the stem (3x1010g/etem, leaf (5x109 g/ leaf, flag leaf (3x109 g/ flag leaf and with less density in panicle (4x108 g/panicle. The results of the identification with kit API were confirmed the presence of endophytic bacteria Burkholderia cepaceae and rizospheric bacteria Pseudomona fluorescens With the ability to tolerate different concentrations of Cd, fix nitrogen, solubilize phosphates and produce siderophores.

  15. Pathogenic Assay of Probiotic Bacteria Producing Proteolytic Enzymes as Bioremediation Bacteria Against Vannamei Shrimp Larvae (Litopenaeus vannamei

    Directory of Open Access Journals (Sweden)

    Wilis Ari Setyati

    2017-06-01

    Full Text Available Application of bacteria in bioremediation of shrimp culture ponds is one of the methods used to clean internal pollutants. This study aimed to evaluate the pathogenicity of extracellular proteolytic enzyme produced by the probiotic bacteria as bioremediation bacteria on vannamei shrimp larvae culture. There were five probiotic bacteria, which were successfully isolated from the sediments served as substrate in mangrove area. The isolated bacteria were coded in number as 13, 19, 30, 33, and 36. Pathogenic bacteria Vibrio harveyi was used as positive control. Pathogenic assay was carried out in two different bacterial concentrations, i.e. 10⁸ and 10⁶ cells.mL-1. The results showed that the lowest survival rate (SR of shrimp larvae in positive control V. harveyi was 53 and 65%. Whereas isolates with the highest SR value (100% were obtained from bacteria coded as 13 and 30. Isolates no. 19, 33 and 36 had SR of more than 90%. Total plate count (TPC data showed that the bacteria increased significantly at the end of the study with an average increase value of 24%. The smallest TPC value was shown by bacterial isolate no. 19, while the largest was obtained from the isolate no. 13. These results suggest that all probiotic bacteria were not pathogenic to the vannamei shrimp larvae.   Keywords: aquaculture, shrimp, bioremediation, pathogenesis, vibrio.

  16. Isolation of Crude Oil from Polluted Waters Using Biosurfactants Pseudomonas Bacteria: Assessment of Bacteria Concentration Effects

    Directory of Open Access Journals (Sweden)

    A. Khalifeh

    2013-04-01

    Full Text Available Biological decomposition techniques and isolation of environmental pollutions using biosurfactants bacteria are effective methods of environmental protection. Surfactants are amphiphilic compounds that are produced by local microorganisms and are able to reduce the surface and the stresses between surfaces. As a result, they will increase solubility, biological activity, and environmental decomposition of organic compounds. This study analyzes the effects of biosurfactants on crude oil recovery and its isolation using pseudomonas sea bacteria species. Preparation of biosurfactants was done in glass flasks and laboratory conditions. Experiments were carried out to obtain the best concentration of biosurfactants for isolating oil from water and destroying oil-in-water or water-in-oil emulsions in two pH ranges and four saline solutions of different concentrations. The most effective results were gained when a concentration of 0.1% biosurfactants was applied.

  17. Determination of Ammonia Oxidizing Bacteria and Nitrate Oxidizing Bacteria in Wastewater and Bioreactors

    Science.gov (United States)

    Francis, Somilez Asya

    2014-01-01

    The process of water purification has many different physical, chemical, and biological processes. One part of the biological process is the task of ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB). Both play critical roles in the treatment of wastewater by oxidizing toxic compounds. The broad term is nitrification, a naturally occurring process that is carried out by AOB and NOB by using oxidation to convert ammonia to nitrite and nitrite to nitrate. To monitor this biological activity, bacterial staining was performed on wastewater contained in inoculum tanks and biofilm samples from bioreactors. Using microscopy and qPCR, the purpose of this experiment was to determine if the population of AOB and NOB in wastewater and membrane bioreactors changed depending on temperature and hibernation conditions to determine the optimal parameters for AOB/NOB culture to effectively clean wastewater.

  18. Bacteria, some permanent tenants Space Station; Bacteria, unos inquilinos permanentes de la estacion espacial

    Energy Technology Data Exchange (ETDEWEB)

    Diaz, B.

    2015-07-01

    Vacuum cleaners to operate the vacuum or rags with ethanol they are the products of cleaning of the astronauts. Is there tight spaces fully sterilized? It seems not, even in the Space Station International (ISS). When it comes to bacteria, they are able to travel more than 400 kilometers housed in costumes, bodies and interior of the astronauts themselves and settle in a enclosed space where-unlike in a {sup c}leanroom 'terrestre- the air is not recycled. A NASA study has found an abundance of bacteria 'opportunists' which, although harmless on Earth, they might derivasen cause infections in inflammations or skin irritations. Not forgetting those fungi that could damage or affect the infrastructure equipment space. (Author)

  19. Seed-vectored endophytic bacteria modulate development of rice seedlings.

    Science.gov (United States)

    Verma, S K; Kingsley, K; Irizarry, I; Bergen, M; Kharwar, R N; White, J F

    2017-06-01

    The aim of the present study was to evaluate the effects of the removal of indigenous bacteria from rice seeds on seedling growth and development. Here we report the presence of three indigenous endophytic bacteria in rice seeds that play important roles in modulating seedling development (shoot and root lengths, and formation of root hairs and secondary roots) and defence against pathogens. Seed-associated bacteria were removed using surface sterilization with NaOCl (bleach) followed by antibiotic treatment. When bacteria were absent, growth of seedlings in terms of root hair development and overall seedling size was less than that of seedlings that contained bacteria. Reactive oxygen staining of seedlings showed that endophytic bacteria became intracellular in root parenchyma cells and root hairs. Roots containing endophytic bacteria were seen to stain densely for reactive oxygen, while roots free of bacteria stained lightly for reactive oxygen. Bacteria were isolated and identified as Enterobacter asburiae (VWB1), Pantoea dispersa (VWB2) and Pseudomonas putida (VWB3) by 16S rDNA sequencing. Bacteria were found to produce indole acetic acid (auxins), inhibited the pathogen Fusarium oxysporum and solubilized phosphate. Reinoculation of bacteria onto seedlings derived from surface-disinfected rice and Bermuda grass seeds significantly restored seedling growth and development. Rice seeds harbour indigenous bacterial endophytes that greatly influence seedling growth and development, including root and shoot lengths, root hair formation and disease susceptibility of rice seedlings. This study shows that seeds of rice naturally harbour bacterial endophytes that play key roles in modulation of seedling development. © 2017 The Society for Applied Microbiology.

  20. BioNLP Shared Task--The Bacteria Track.

    Science.gov (United States)

    Bossy, Robert; Jourde, Julien; Manine, Alain-Pierre; Veber, Philippe; Alphonse, Erick; van de Guchte, Maarten; Bessières, Philippe; Nédellec, Claire

    2012-06-26

    We present the BioNLP 2011 Shared Task Bacteria Track, the first Information Extraction challenge entirely dedicated to bacteria. It includes three tasks that cover different levels of biological knowledge. The Bacteria Gene Renaming supporting task is aimed at extracting gene renaming and gene name synonymy in PubMed abstracts. The Bacteria Gene Interaction is a gene/protein interaction extraction task from individual sentences. The interactions have been categorized into ten different sub-types, thus giving a detailed account of genetic regulations at the molecular level. Finally, the Bacteria Biotopes task focuses on the localization and environment of bacteria mentioned in textbook articles. We describe the process of creation for the three corpora, including document acquisition and manual annotation, as well as the metrics used to evaluate the participants' submissions. Three teams submitted to the Bacteria Gene Renaming task; the best team achieved an F-score of 87%. For the Bacteria Gene Interaction task, the only participant's score had reached a global F-score of 77%, although the system efficiency varies significantly from one sub-type to another. Three teams submitted to the Bacteria Biotopes task with very different approaches; the best team achieved an F-score of 45%. However, the detailed study of the participating systems efficiency reveals the strengths and weaknesses of each participating system. The three tasks of the Bacteria Track offer participants a chance to address a wide range of issues in Information Extraction, including entity recognition, semantic typing and coreference resolution. We found common trends in the most efficient systems: the systematic use of syntactic dependencies and machine learning. Nevertheless, the originality of the Bacteria Biotopes task encouraged the use of interesting novel methods and techniques, such as term compositionality, scopes wider than the sentence.

  1. Acetic acid bacteria: A group of bacteria with versatile biotechnological applications.

    Science.gov (United States)

    Saichana, Natsaran; Matsushita, Kazunobu; Adachi, Osao; Frébort, Ivo; Frebortova, Jitka

    2015-11-01

    Acetic acid bacteria are gram-negative obligate aerobic bacteria assigned to the family Acetobacteraceae of Alphaproteobacteria. They are members of the genera Acetobacter, Gluconobacter, Gluconacetobacter, Acidomonas, Asaia, Kozakia, Swaminathania, Saccharibacter, Neoasaia, Granulibacter, Tanticharoenia, Ameyamaea, Neokomagataea, and Komagataeibacter. Many strains of Acetobacter and Komagataeibacter have been known to possess high acetic acid fermentation ability as well as the acetic acid and ethanol resistance, which are considered to be useful features for industrial production of acetic acid and vinegar, the commercial product. On the other hand, Gluconobacter strains have the ability to perform oxidative fermentation of various sugars, sugar alcohols, and sugar acids leading to the formation of several valuable products. Thermotolerant strains of acetic acid bacteria were isolated in order to serve as the new strains of choice for industrial fermentations, in which the cooling costs for maintaining optimum growth and production temperature in the fermentation vessels could be significantly reduced. Genetic modifications by adaptation and genetic engineering were also applied to improve their properties, such as productivity and heat resistance. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Detection of Sulphate-Reducing Bacteria and Others Cultivable Facultative Bacteria in Dental Tissues

    Directory of Open Access Journals (Sweden)

    Lúcio de Souza Gonçalves

    2014-01-01

    Full Text Available Aim: To detect for the presence of sulphate-reducing bacteria (SRB and evaluate the possible association between SRB and cultivable facultative bacterial of oral sites with different periodontal conditions. Methods: The study was carried out on 9 samples from different oral sites in 8 patients (two samples were collected from the same patient. Material was collected using modified Postgate E culture medium, indicated for the growth and isolation of SRB. In addition, a reducing solution for anaerobic bacteria was used as a transport solution for facultative bacteria and identified by polymerase chain reaction amplification (PCR and sequencing of the 16S rRNA gene. Results: SRB was found in 3 patient samples: the first in a root fragment, the second in a root fragment and a healthy tooth with vertical bone loss and a mobility degree of 3; and the third in a healthy tooth extracted for orthodontic treatment. In the final patient, the cultivable facultative species Lactobacillus casei was identified. Other facultative bacterial species were identified in patient 5 (Kurthia Gibsonii and patient 7 (Pseudomonas aeruginosa. Conclusions: The detection of SRB in different dental tissues with distinct periodontal features demonstrated that new studies need to be developed in order to determine the true role of SRB in the oral microbiota. In addition, it was possible to verify the presence of Lactobacillus casei together with SRB in one sample.

  3. Mechanistic modeling of biocorrosion caused by biofilms of sulfate reducing bacteria and acid producing bacteria.

    Science.gov (United States)

    Xu, Dake; Li, Yingchao; Gu, Tingyue

    2016-08-01

    Biocorrosion is also known as microbiologically influenced corrosion (MIC). Most anaerobic MIC cases can be classified into two major types. Type I MIC involves non-oxygen oxidants such as sulfate and nitrate that require biocatalysis for their reduction in the cytoplasm of microbes such as sulfate reducing bacteria (SRB) and nitrate reducing bacteria (NRB). This means that the extracellular electrons from the oxidation of metal such as iron must be transported across cell walls into the cytoplasm. Type II MIC involves oxidants such as protons that are secreted by microbes such as acid producing bacteria (APB). The biofilms in this case supply the locally high concentrations of oxidants that are corrosive without biocatalysis. This work describes a mechanistic model that is based on the biocatalytic cathodic sulfate reduction (BCSR) theory. The model utilizes charge transfer and mass transfer concepts to describe the SRB biocorrosion process. The model also includes a mechanism to describe APB attack based on the local acidic pH at a pit bottom. A pitting prediction software package has been created based on the mechanisms. It predicts long-term pitting rates and worst-case scenarios after calibration using SRB short-term pit depth data. Various parameters can be investigated through computer simulation. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Laminar flow assisted anisotropic bacteria absorption for chemotaxis delivery of bacteria-attached microparticle

    Science.gov (United States)

    Huh, Keon; Oh, Darong; Son, Seok Young; Yoo, Hyung Jung; Song, Byeonghwa; Cho, Dong-il Dan; Seo, Jong-Mo; Kim, Sung Jae

    2016-12-01

    The concepts of microrobots has been drawn significant attentions recently since its unprecedented applicability in nanotechnology and biomedical field. Bacteria attached microparticles presented in this work are one of pioneering microrobot technology for self-propulsion or producing kinetic energy from ambient for their motions. Microfluidic device, especially utilizing laminar flow characteristics, were employed for anisotropic attachment of Salmonella typhimurium flagellated chemotactic bacteria to 30 um × 30 um and 50 um × 50 um microparticles that made of biodegradable polymer. Any toxic chemicals or harmful treatments were excluded during the attachment process and it finished within 100 s for the anisotropic attachment. The attachments were directly confirmed by fluorescent intensity changes and SEM visualization. Chemotaxis motions were tracked using aspartate and the maximum velocity of the bacteria-attached microrobot was measured to be 5 um/s which is comparable to prior state of art technologies. This reusable and scalable method could play a key role in chemotaxis delivery of functional microparticles such as drug delivery system.

  5. Bioactive proteins against pathogenic and spoilage bacteria

    Directory of Open Access Journals (Sweden)

    Mahmoud Z. Sitohy

    2014-10-01

    Full Text Available Background: It is likely that both human nutrition and the nutrition of livestock are benefited by the presence of bioactive proteins within their respective diet regimes. Bioactive proteins have been defined as specific protein fragments that positively impact bodily functions or conditions and may, ultimately, influence overall human health. The ingestion of bioactive proteins may have an effect on the major body systems—namely, the cardiovascular, digestive, immune and nervous systems. According to their functional properties, bioactive proteins may be classified as antimicrobial, antithrombotic, antihypertensive, opioid, immune-modulatory, mineral binding and anti-oxidative. There are many examples of biologically active food proteins and active peptides that can be obtained from various food protein sources. They have a physiological significance beyond the pure nutritional requirements; in other wordsthey have the acquisition of nitrogen for normal growth and maintenance. Objective: This study aims to specify and characterize the extent and mode of action of bioactive proteins in their native form, (glycinin, glycinin basic sub-unit and β-conglycinin against specific main pathogens (Listeria monocytogenes, Escherichia coli O157:H7 and Salmonella enterica serovar Enteritidis. We will be using standard media while identifying the main constituents responsible for this action. Methods: Glycinin, basic sub-unit and β-conglycinin were isolated from soybean protein and tested for their antimicrobial action against pathogenic and spoilage bacteria, They were thencompared to the properties of penicillin. Methylated soybean protein and also methylated chickpea protein (MSP and MCP, with isoelectric points around pI 8, were prepared by esterifying. 83 % of their free carboxyl groups and their interactions with Gram positive and Gram negative bacteria were examined. Results: The three divisions of cationic proteins exhibited antibacterial

  6. Analytical strategies for phosphoproteomics

    DEFF Research Database (Denmark)

    Thingholm, Tine E; Jensen, Ole N; Larsen, Martin R

    2009-01-01

    sensitive and specific strategies. Today, most phosphoproteomic studies are conducted by mass spectrometric strategies in combination with phospho-specific enrichment methods. This review presents an overview of different analytical strategies for the characterization of phosphoproteins. Emphasis...

  7. Seeing green bacteria in a new light: genomics-enabled studies of the photosynthetic apparatus in green sulfur bacteria and filamentous anoxygenic phototrophic bacteria

    DEFF Research Database (Denmark)

    Frigaard, Niels-Ulrik; Bryant, Donald A

    2004-01-01

    Based upon their photosynthetic nature and the presence of a unique light-harvesting antenna structure, the chlorosome, the photosynthetic green bacteria are defined as a distinctive group in the Bacteria. However, members of the two taxa that comprise this group, the green sulfur bacteria...... (Chlorobi) and the filamentous anoxygenic phototrophic bacteria ("Chloroflexales"), are otherwise quite different, both physiologically and phylogenetically. This review summarizes how genome sequence information facilitated studies of the biosynthesis and function of the photosynthetic apparatus...... a and carotenoid biosynthesis enzymes, gene cluster analysis in Cfx. aurantiacus, and gene inactivation studies in Chl. tepidum. Based on these results, BChl a and BChl c biosynthesis is similar in the two organisms, whereas carotenoid biosynthesis differs significantly. In agreement with its facultative anaerobic...

  8. Development of novel strategies to combat multidrug resistance mediated by efflux transporters and intracellular bacteria

    OpenAIRE

    Kuriakose, Jerrin

    2014-01-01

    Multidrug resistance (MDR) is the condition where cancer cells or microorganisms cease to respond to multiple drugs. MDR conferred by efflux transporters, that deprive the bioavailability of drugs at their site of action, are a threat to cancer and malarial chemotherapy. Specifically, the mammalian ABC transporter Pglycoprotein (P-gp) has undermined many drugs in treatment of cancer and other disease states. Mutations in the parasitic transporter Plasmodium falciparum chloroquine resistance t...

  9. Experimental evolution and the adjustment of metabolic strategies in lactic acid bacteria

    NARCIS (Netherlands)

    Bachmann, Herwig; Molenaar, Douwe; Branco dos Santos, Filipe; Teusink, Bas

    2017-01-01

    Experimental evolution of microbes has gained lots of interest in recent years, mainly due to the ease of strain characterisation through next-generation sequencing. While evolutionary and systems biologists use experimental evolution to address fundamental questions in their respective fields,

  10. Lipid remodelling is a widespread strategy in marine heterotrophic bacteria upon phosphorus deficiency

    Czech Academy of Sciences Publication Activity Database

    Sebastián, M.; Smith, A.F.; Gonzáles, J.M.; Fredricks, H. F.; Van Mooy, B.; Koblížek, Michal; Brandsma, J.; Koster, G.; Mestre, M.; Mostajir, B.; Pitta, P.; Postle, A.D.; Sánchez, P.; Gasol, J.M.; Scanlan, D.J.; Chen, Y.

    2016-01-01

    Roč. 10, č. 4 (2016), s. 968-978 ISSN 1751-7362 R&D Projects: GA ČR GA13-11281S Institutional support: RVO:61388971 Keywords : NORTH-ATLANTIC OCEAN * MICROBIAL FOOD-WEB * NUTRIENT LIMITATION Subject RIV: EE - Microbiology, Virology Impact factor: 9.664, year: 2016

  11. Ada response - a strategy for repair of alkylated DNA in bacteria.

    Science.gov (United States)

    Mielecki, Damian; Grzesiuk, Elżbieta

    2014-06-01

    Alkylating agents are widespread in the environment and also occur endogenously. They can be cytotoxic or mutagenic to the cells introducing alkylated bases to DNA or RNA. All organisms have evolved multiple DNA repair mechanisms to counteract the effects of DNA alkylation: the most cytotoxic lesion, N(3)-methyladenine (3meA), is excised by AlkA glycosylase initiating base excision repair (BER); toxic N(1)-methyladenine (1meA) and N(3)-methylcytosine (3meC), induced in DNA and RNA, are removed by AlkB dioxygenase; and mutagenic and cytotoxic O(6)-methylguanine (O(6) meG) is repaired by Ada methyltransferase. In Escherichia coli, Ada response involves the expression of four genes, ada, alkA, alkB, and aidB, encoding respective proteins Ada, AlkA, AlkB, and AidB. The Ada response is conserved among many bacterial species; however, it can be organized differently, with diverse substrate specificity of the particular proteins. Here, an overview of the organization of the Ada regulon and function of individual proteins is presented. We put special effort into the characterization of AlkB dioxygenases, their substrate specificity, and function in the repair of alkylation lesions in DNA/RNA. © 2014 The Authors. FEMS Microbiology Letters published by John Wiley & Sons Ltd on behalf of Federation of European Microbiological Societies.

  12. Ada response – a strategy for repair of alkylated DNA in bacteria

    Science.gov (United States)

    Mielecki, Damian; Grzesiuk, Elżbieta

    2014-01-01

    Alkylating agents are widespread in the environment and also occur endogenously. They can be cytotoxic or mutagenic to the cells introducing alkylated bases to DNA or RNA. All organisms have evolved multiple DNA repair mechanisms to counteract the effects of DNA alkylation: the most cytotoxic lesion, N3-methyladenine (3meA), is excised by AlkA glycosylase initiating base excision repair (BER); toxic N1-methyladenine (1meA) and N3-methylcytosine (3meC), induced in DNA and RNA, are removed by AlkB dioxygenase; and mutagenic and cytotoxic O6-methylguanine (O6meG) is repaired by Ada methyltransferase. In Escherichia coli, Ada response involves the expression of four genes, ada, alkA, alkB, and aidB, encoding respective proteins Ada, AlkA, AlkB, and AidB. The Ada response is conserved among many bacterial species; however, it can be organized differently, with diverse substrate specificity of the particular proteins. Here, an overview of the organization of the Ada regulon and function of individual proteins is presented. We put special effort into the characterization of AlkB dioxygenases, their substrate specificity, and function in the repair of alkylation lesions in DNA/RNA. PMID:24810496

  13. Strategy Development in Organisations

    DEFF Research Database (Denmark)

    Sørensen, Lene

    1999-01-01

    There exist certain ambiguities with the converging fields of information technology and organisational strategy development. The term "IT strategy" has evolved and reflects in some respects this confusion. This paper discusses some of the ambiguities and difficulties of the term "IT strategy......" as used in practice and literature. Emphasis is put on how the term is related to the problem, the organisation, the strategy process and the practical way of methodologically developing the strategy. Finally, alternative strategy developing perspectives are presented....

  14. Microbial leaching of iron from pyrite by moderate thermophile chemolithotropic bacteria

    International Nuclear Information System (INIS)

    Ilyas, S.; Niazi, S.B.

    2007-01-01

    The present work was aimed at studying the bioleachability of iron from pyrite by the selected moderately thermophilic strains of acidophilic chemolithotrophic and acidophilic heterotrophic bacteria. These included Sulfobacillus thermosulfidooxidans (chemolithotroph) and an un-identified strain of acidophilic heterotroph (code 6A1TSB) isolated from local environments. As compared to inoculated flasks, dissolution of metal (due to acid leaching) was significantly low in the un-inoculated control flasks in all the experiments in ore. A decrease in the bioleaching activity was observed at the later stages of bioleaching of metal from ore. Among the strategies adopted to enhance the metal leaching rates, a mixed consortium of the metal adapted cultures of the above-mentioned bacteria was found to exhibit the maximum metal leaching efficiency. In all the flasks where high metal leaching rates were observed, concomitantly biomass production rates were also high indicating high growth rates. It showed that the metal bioleaching capability of the bacteria was associated with their growth. Pyrite contained 42% iron. (author)

  15. Bacteria-mediated arsenic oxidation and reduction in the growth media of arsenic hyperaccumulator Pteris vittata.

    Science.gov (United States)

    Wang, Xin; Rathinasabapathi, Bala; de Oliveira, Letuzia Maria; Guilherme, Luiz R G; Ma, Lena Q

    2012-10-16

    Microbes play an important role in arsenic transformation and cycling in the environment. Microbial arsenic oxidation and reduction were demonstrated in the growth media of arsenic hyperaccumulator Pteris vittata L. All arsenite (AsIII) at 0.1 mM in the media was oxidized after 48 h incubation. Oxidation was largely inhibited by antibiotics, indicating that bacteria played a dominant role. To identify AsIII oxidizing bacteria, degenerate primers were used to amplify ∼500 bp of the AsIII oxidase gene aioA (aroA) using DNA extracted from the media. One aioA (aroA)-like sequence (MG-1, tentatively identified as Acinetobacter sp.) was amplified, exhibiting 82% and 91% identity in terms of gene and deduced protein sequence to those from Acinetobacter sp. 33. In addition, four bacterial strains with different arsenic tolerance were isolated and identified as Comamonas sp.C-1, Flavobacterium sp. C-2, Staphylococcus sp. C-3, and Pseudomonas sp. C-4 using carbon utilization, fatty acid profiles, and/or sequencing 16s rRNA gene. These isolates exhibited dual capacity for both AsV reduction and AsIII oxidation under ambient conditions. Arsenic-resistant bacteria with strong AsIII oxidizing ability may have potential to improve bioremediation of AsIII-contaminated water using P. vittata and/or other biochemical strategies.

  16. Desiccation: An environmental and food industry stress that bacteria commonly face.

    Science.gov (United States)

    Esbelin, Julia; Santos, Tiago; Hébraud, Michel

    2018-02-01

    Water is essential for all living organisms, for animals as well as for plants and micro-organisms. For these latter, the presence of water or a humid environment with a high air relative humidity (RH) is necessary for their survival and growth. Thus, variations in the availability of water or in the air relative humidity constitute widespread environmental stresses which challenge microorganisms, and especially bacteria. Indeed, in their direct environment, bacteria are often faced with conditions that remove cell-bound water through air-drying of the atmosphere. Bacterial cells are subject to daily or seasonal environmental variations, sometimes going through periods of severe desiccation. This is also the case in the food industry, where air dehumidification treatments are applied after the daily cleaning-disinfection procedures. In plants producing low-water activity products, it is also usual to significantly reduce or eliminate water usage. Periodic desiccation exposure affects bacteria viability and so they require strategies to persist. Negative effects of desiccation are wide ranging and include direct cellular damage but also changes in the biochemical and biophysical properties of cells for which planktonic cells are more exposed than cells in biofilm. Understanding the mechanisms of desiccation adaptation and tolerance has a biological and biotechnological interest. This review gives an overview of the factors influencing desiccation tolerance and the biological mechanisms involved in this stress response. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Lindane Bioremediation Capability of Bacteria Associated with the Demosponge Hymeniacidon perlevis

    Directory of Open Access Journals (Sweden)

    Stabili Loredana

    2017-04-01

    Full Text Available Lindane is an organochlorine pesticide belonging to persistent organic pollutants (POPs that has been widely used to treat agricultural pests. It is of particular concern because of its toxicity, persistence and tendency to bioaccumulate in terrestrial and aquatic ecosystems. In this context, we assessed the role of bacteria associated with the sponge Hymeniacidon perlevis in lindane degradation. Seven bacteria isolates were characterized and identified. These isolates showed a remarkable capacity to utilize lindane as a sole carbon source leading to a percentage of residual lindane ranging from 3% to 13% after 12 days of incubation with the pesticide. The lindane metabolite, 1,3–6-pentachloro-cyclohexene, was identified as result of lindane degradation and determined by gas chromatography–mass spectrometry (GC–MS. The bacteria capable of lindane degradation were identified on the basis of the phenotypic characterization by morphological, biochemical and cultural tests, completed with 16S rDNA sequence analysis, and assigned to Mameliella phaeodactyli, Pseudovibrio ascidiaceicola, Oceanicaulis stylophorae, Ruegeria atlantica and to three new uncharacterized species. The results obtained are a prelude to the development of future strategies for the in situ bioremediation of lindane.

  18. Effect of nematodes on rhizosphere colonization by seed-applied bacteria.

    Science.gov (United States)

    Knox, Oliver G G; Killham, Ken; Artz, Rebekka R E; Mullins, Chris; Wilson, Michael

    2004-08-01

    There is much interest in the use of seed-applied bacteria for biocontrol and biofertilization, and several commercial products are available. However, many attempts to use this strategy fail because the seed-applied bacteria do not colonize the rhizosphere. Mechanisms of rhizosphere colonization may involve active bacterial movement or passive transport by percolating water or plant roots. Transport by other soil biota is likely to occur, but this area has not been well studied. We hypothesized that interactions with soil nematodes may enhance colonization. To test this hypothesis, a series of microcosm experiments was carried out using two contrasting soils maintained under well-defined physical conditions where transport by mass water flow could not occur. Seed-applied Pseudomonas fluorescens SBW25 was capable of rhizosphere colonization at matric potentials of -10 and -40 kPa in soil without nematodes, but colonization levels were substantially increased by the presence of nematodes. Our results suggest that nematodes can have an important role in rhizosphere colonization by bacteria in soil.

  19. Interactions between Bacteria and Bile Salts in the Gastrointestinal and Hepatobiliary Tracts

    Directory of Open Access Journals (Sweden)

    Verónica Urdaneta

    2017-10-01

    Full Text Available Bile salts and bacteria have intricate relationships. The composition of the intestinal pool of bile salts is shaped by bacterial metabolism. In turn, bile salts play a role in intestinal homeostasis by controlling the size and the composition of the intestinal microbiota. As a consequence, alteration of the microbiome–bile salt homeostasis can play a role in hepatic and gastrointestinal pathological conditions. Intestinal bacteria use bile salts as environmental signals and in certain cases as nutrients and electron acceptors. However, bile salts are antibacterial compounds that disrupt bacterial membranes, denature proteins, chelate iron and calcium, cause oxidative damage to DNA, and control the expression of eukaryotic genes involved in host defense and immunity. Bacterial species adapted to the mammalian gut are able to endure the antibacterial activities of bile salts by multiple physiological adjustments that include remodeling of the cell envelope and activation of efflux systems and stress responses. Resistance to bile salts permits that certain bile-resistant pathogens can colonize the hepatobiliary tract, and an outstanding example is the chronic infection of the gall bladder by Salmonella enterica. A better understanding of the interactions between bacteria and bile salts may inspire novel therapeutic strategies for gastrointestinal and hepatobiliary diseases that involve microbiome alteration, as well as novel schemes against bacterial infections.

  20. Vapor-induced transfer of bacteria in the absence of mechanical disturbances

    KAUST Repository

    Ayoub, George M.

    2014-09-01

    Transfer of bacteria through water vapor generated at moderate temperatures (30-50. °C) in passive solar stills, has scarcely been reported. The objective of this research was to investigate whether bacteria in highly humid atmospheres can get transferred through water vapor in the absence of other transfer media to find their way to the distillate. To achieve this objective, passive solar reactors were chosen as the medium for experimentation, and distillation experiments were conducted by spiking a pure bacterial culture (Escherichia coli, Klebsiella pneumonia or Enterococcus faecalis) in low mineralized water vs. highly mineralized water in the dark under moderate temperatures ranges (30-35. °C, 40-45. °C and 50-55. °C). Results showed that bacteria indeed get transferred with the vapor in stills when not exposed to solar U.V. radiation. The trends observed were adequately explained by a zero-modified Hurdle-Poisson model. The numbers of cultivable bacterial colonies transferred were bacterial size, water type and temperature dependent with highest transfers occurring in E. faecalis>. E. coli>. K. pneumonia at the 40. °C range in low mineralized water. Proper management strategies are recommended to achieve complete disinfection in solar stills. © 2014 Elsevier B.V.