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Sample records for non-photosynthetic sulphide-oxidizing bacteria

  1. Endosymbiotic sulphate-reducing and sulphide-oxidizing bacteria in an oligochaete worm.

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    Dubilier, N; Mülders, C; Ferdelman, T; de Beer, D; Pernthaler, A; Klein, M; Wagner, M; Erséus, C; Thiermann, F; Krieger, J; Giere, O; Amann, R

    2001-05-17

    Stable associations of more than one species of symbiont within a single host cell or tissue are assumed to be rare in metazoans because competition for space and resources between symbionts can be detrimental to the host. In animals with multiple endosymbionts, such as mussels from deep-sea hydrothermal vents and reef-building corals, the costs of competition between the symbionts are outweighed by the ecological and physiological flexibility gained by the hosts. A further option for the coexistence of multiple symbionts within a host is if these benefit directly from one another, but such symbioses have not been previously described. Here we show that in the gutless marine oligochaete Olavius algarvensis, endosymbiotic sulphate-reducing bacteria produce sulphide that can serve as an energy source for sulphide-oxidizing symbionts of the host. Thus, these symbionts do not compete for resources but rather share a mutalistic relationship with each other in an endosymbiotic sulphur cycle, in addition to their symbiotic relationship with the oligochaete host.

  2. Nitrite reductase activity of sulphate-reducing bacteria prevents their inhibition by nitrate-reducing, sulphide-oxidizing bacteria.

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    Greene, E A; Hubert, C; Nemati, M; Jenneman, G E; Voordouw, G

    2003-07-01

    Sulphate-reducing bacteria (SRB) can be inhibited by nitrate-reducing, sulphide-oxidizing bacteria (NR-SOB), despite the fact that these two groups are interdependent in many anaerobic environments. Practical applications of this inhibition include the reduction of sulphide concentrations in oil fields by nitrate injection. The NR-SOB Thiomicrospira sp. strain CVO was found to oxidize up to 15 mM sulphide, considerably more than three other NR-SOB strains that were tested. Sulphide oxidation increased the environmental redox potential (Eh) from -400 to +100 mV and gave 0.6 nitrite per nitrate reduced. Within the genus Desulfovibrio, strains Lac3 and Lac6 were inhibited by strain CVO and nitrate for the duration of the experiment, whereas inhibition of strains Lac15 and D. vulgaris Hildenborough was transient. The latter had very high nitrite reductase (Nrf) activity. Southern blotting with D. vulgaris nrf genes as a probe indicated the absence of homologous nrf genes from strains Lac3 and Lac6 and their presence in strain Lac15. With respect to SRB from other genera, inhibition of the known nitrite reducer Desulfobulbus propionicus by strain CVO and nitrate was transient, whereas inhibition of Desulfobacterium autotrophicum and Desulfobacter postgatei was long-lasting. The results indicate that inhibition of SRB by NR-SOB is caused by nitrite production. Nrf-containing SRB can overcome this inhibition by further reducing nitrite to ammonia, preventing a stalling of the favourable metabolic interactions between these two bacterial groups. Nrf, which is widely distributed in SRB, can thus be regarded as a resistance factor that prevents the inhibition of dissimilatory sulphate reduction by nitrite.

  3. Asymmetrically acting lycopene beta-cyclases (CrtLm) from non-photosynthetic bacteria.

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    Tao, L; Picataggio, S; Rouvière, P E; Cheng, Q

    2004-03-01

    Carotenoids have important functions in photosynthesis, nutrition, and protection against oxidative damage. Some natural carotenoids are asymmetrical molecules that are difficult to produce chemically. Biological production of carotenoids using specific enzymes is a potential alternative to extraction from natural sources. Here we report the isolation of lycopene beta-cyclases that selectively cyclize only one end of lycopene or neurosporene. The crtLm genes encoding the asymmetrically acting lycopene beta-cyclases were isolated from non-photosynthetic bacteria that produced monocyclic carotenoids. Co-expression of these crtLm genes with the crtEIB genes from Pantoea stewartii (responsible for lycopene synthesis) resulted in the production of monocyclic gamma-carotene in Escherichia coli. The asymmetric cyclization activity of CrtLm could be inhibited by the lycopene beta-cyclase inhibitor 2-(4-chlorophenylthio)-triethylamine (CPTA). Phylogenetic analysis suggested that bacterial CrtL-type lycopene beta-cyclases might represent an evolutionary link between the common bacterial CrtY-type of lycopene beta-cyclases and plant lycopene beta- and epsilon-cyclases. These lycopene beta-cyclases may be used for efficient production of high-value asymmetrically cyclized carotenoids.

  4. Oxidação de sulfetos de níquel com microorganismos mesófilos Nickel sulphide oxidation by mesophile bacteria

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    Luciano Rodrigo Gomes Santos

    2008-03-01

    Full Text Available A oxidação de sulfetos metálicos tem sido associada à drenagem ácida de mina, um dos maiores problemas ambientais na mineração. Uma das formas de se acelerar a oxidação desses sulfetos é a biolixivação, na qual o crescimento desses microorganismos é favorecido. Foi estudada, nesse trabalho, a oxidação de um concentrado sulfetado complexo de pentlandita/pirrotita utilizando bactérias mesófilas. Foram avaliados os efeitos do pH e do percentual de sólidos sobre a extração do níquel. Os resultados indicaram que a biolixiviação pode ser uma alternativa viável ao processamento de sulfetos complexos de ferro e de níquel, uma vez que foram obtidos percentuais de extração acima de 60%. O pH possui pequena influência nos percentuais de extração obtidos, sendo o valor ideal igual a 2,0. Sua influência parece estar ligada, principalmente, à regulação da atividade bacteriana. Percentuais de sólidos elevados (aproximadamente de 10% podem ser praticados, sem apresentarem diferenças significativas na extração final de níquel, pois a transferência gasosa no sistema é pouco comprometida. Dessa forma, o fator limitante da atividade bacteriana, em percentuais elevados de sólidos, é a disponibilidade de dióxido de carbono.Metallic sulphide oxidation has been associated to the generation of acid mine drainage, one of the most import environmental issues in the mining industry. Bioleaching can be applied to accelerate sulphide oxidation, ceasing these impacts. This work sought to study the biooxidation of a complex nickel-iron sulphide (pentlandite and pyrrhotite using acidophile iron-oxidizing bacteria. The effects of pH and solids concentration on the extraction of nickel were evaluated. A high nickel extraction (around 60% can be achieved confirming the feasibility of nickel sulphide bioleaching. The pH has a negligible effect on nickel extraction being pH 2.0 the best value. Nickel dissolution can be achieved at high

  5. The human gut and groundwater harbor non-photosynthetic bacteria belonging to a new candidate phylum sibling to Cyanobacteria.

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    Di Rienzi, Sara C; Sharon, Itai; Wrighton, Kelly C; Koren, Omry; Hug, Laura A; Thomas, Brian C; Goodrich, Julia K; Bell, Jordana T; Spector, Timothy D; Banfield, Jillian F; Ley, Ruth E

    2013-10-01

    Cyanobacteria were responsible for the oxygenation of the ancient atmosphere; however, the evolution of this phylum is enigmatic, as relatives have not been characterized. Here we use whole genome reconstruction of human fecal and subsurface aquifer metagenomic samples to obtain complete genomes for members of a new candidate phylum sibling to Cyanobacteria, for which we propose the designation 'Melainabacteria'. Metabolic analysis suggests that the ancestors to both lineages were non-photosynthetic, anaerobic, motile, and obligately fermentative. Cyanobacterial light sensing may have been facilitated by regulators present in the ancestor of these lineages. The subsurface organism has the capacity for nitrogen fixation using a nitrogenase distinct from that in Cyanobacteria, suggesting nitrogen fixation evolved separately in the two lineages. We hypothesize that Cyanobacteria split from Melainabacteria prior or due to the acquisition of oxygenic photosynthesis. Melainabacteria remained in anoxic zones and differentiated by niche adaptation, including for symbiosis in the mammalian gut. DOI:http://dx.doi.org/10.7554/eLife.01102.001.

  6. The human gut and groundwater harbor non-photosynthetic bacteria belonging to a new candidate phylum sibling to Cyanobacteria

    Science.gov (United States)

    Di Rienzi, Sara C; Sharon, Itai; Wrighton, Kelly C; Koren, Omry; Hug, Laura A; Thomas, Brian C; Goodrich, Julia K; Bell, Jordana T; Spector, Timothy D; Banfield, Jillian F; Ley, Ruth E

    2013-01-01

    Cyanobacteria were responsible for the oxygenation of the ancient atmosphere; however, the evolution of this phylum is enigmatic, as relatives have not been characterized. Here we use whole genome reconstruction of human fecal and subsurface aquifer metagenomic samples to obtain complete genomes for members of a new candidate phylum sibling to Cyanobacteria, for which we propose the designation ‘Melainabacteria’. Metabolic analysis suggests that the ancestors to both lineages were non-photosynthetic, anaerobic, motile, and obligately fermentative. Cyanobacterial light sensing may have been facilitated by regulators present in the ancestor of these lineages. The subsurface organism has the capacity for nitrogen fixation using a nitrogenase distinct from that in Cyanobacteria, suggesting nitrogen fixation evolved separately in the two lineages. We hypothesize that Cyanobacteria split from Melainabacteria prior or due to the acquisition of oxygenic photosynthesis. Melainabacteria remained in anoxic zones and differentiated by niche adaptation, including for symbiosis in the mammalian gut. DOI: http://dx.doi.org/10.7554/eLife.01102.001 PMID:24137540

  7. Respiratory processes in non-photosynthetic plastids

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    Marta eRenato

    2015-07-01

    Full Text Available Chlororespiration is a respiratory process located in chloroplast thylakoids which consists in an electron transport chain from NAD(PH to oxygen. This respiratory chain involves the NAD(PH dehydrogenase complex, the plastoquinone pool and the plastid terminal oxidase (PTOX, and it probably acts as a safety valve to prevent the over-reduction of the photosynthetic machinery in stress conditions. The existence of a similar respiratory activity in non-photosynthetic plastids has been less studied. Recently, it has been reported that tomato fruit chromoplasts present an oxygen consumption activity linked to ATP synthesis. Etioplasts and amyloplasts contain several electron carriers and some subunits of the ATP synthase, so they could harbor a similar respiratory process. This review provides an update on the study about respiratory processes in chromoplasts, identifying the major gaps that need to be addressed in future research. It also reviews the proteomic data of etioplasts and amyloplasts, which suggest the presence of a respiratory electron transport chain in these plastids.

  8. Non-photosynthetic pigments as potential biosignatures

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    Schwieterman, E. W.; Cockell, C. S.; Meadows, V. S.

    2014-03-01

    Photosynthetic organisms on Earth produce potentially detectable surface reflectance biosignatures due in part to the spectral location and strength of pigment absorption. However, life on Earth uses pigments for a multitude of purposes other than photosynthesis, including coping with extreme environments. Macroscopic environments exist on Earth where the surface reflectance is significantly altered by a nonphotosynthetic pigment, such as the case of hypersaline lakes and ponds (Oren et al. 1992). Here we explore the nature and potential detectability of non-photosynthetic pigments in disk-averaged planetary observations using a combination of laboratory measurements and archival reflectance spectra, along with simulated broadband photometry and spectra. The in vivo visible reflectance spectra of a cross section of pigmented microorganisms are presented to illustrate the spectral diversity of biologically produced pigments. Synthetic broadband colors are generated to show a significant spread in color space. A 1D radiative transfer model (Meadows & Crisp 1996; Crisp 1997) is used to approximate the spectra of scenarios where pigmented organisms are widespread on planets with Earth-like atmospheres. Broadband colors are revisited to show that colors due to surface reflectivity are not robust to the addition of scattering and absorption effects from the atmosphere. We consider a èbest case' plausible scenario for the detection of nonphotosynthetic pigments by using the Virtual Planetary Laboratory's 3D spectral Earth model (Robinson et al. 2011) to explore the detectability of the surface biosignature produced by pigmented halophiles that are widespread on an Earth-analog planet.

  9. A Wood-Waste Cover Prevents Sulphide Oxidation and Treats Acid Effluents at the East-Sullivan Mine Site

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    Germain, D.; Tassé, N.; Cyr, J.

    2004-05-01

    At the East Sullivan site, wood wastes covering the abandoned mine tailings impoundment prevent sulphide oxidation by creating an anoxic environment. The addition of coarse ligneous wastes favours infiltration, resulting in a water table rise. This maintains most tailings saturated and thus provides an additional protection against sulphide oxidation. Moreover, high infiltration allows a more rapid flushing of acid prone groundwater generated prior to the cover placement. Finally, the pore-waters under the cover are characterized by a strong reducing potential and high alkalinity. These conditions favour sulphate reduction and base metal precipitation as sulphides and carbonates. The restoration strategy capitalized on the alkaline and reductive properties of the waters underlying the wood-waste cover. An original treatment of acid effluents, based on the recirculation of water discharging around the impoundment through the organic cover, was implemented in 1998. In 2003, the total volume of water treated was 725 000 m3. Data gathered near the dispersal zone show that despite dispersing acid water, the groundwater pH decreases by only one unit from 7 to 6, during the recirculation period: May to October. However, alkalinity decreases from 800 to 100 mg/L-CaCO3. But it is back up to 800 mg/L the following spring, thanks to sulphate reduction. Fe2+ concentrations near the dispersal zone are maintained below 2 mg/L. Evolution of the iron mass in the surface waters suggests that the contaminated groundwater flush is completed in the north and west sectors of the impoundment; the east and south ones are expected to be recovered within 3 to 4 years. A wood-waste cover, besides limiting sulphide oxidation, can fill the role of alkaline reducing barrier for the treatment of these acidogenic waters, until a balance between acidity and alkalinity in the effluent is reached.

  10. A novel carotenoid 1,2-hydratase (CruF) from two species of the non-photosynthetic bacterium Deinococcus.

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    Sun, Zongtao; Shen, Shaochuan; Wang, Chao; Wang, Hu; Hu, Yaping; Jiao, Jiandong; Ma, Tingting; Tian, Bing; Hua, Yuejin

    2009-08-01

    A novel carotenoid 1,2-hydratase (CruF) responsible for the C-1',2' hydration of gamma-carotene was identified in the non-photosynthetic bacteria Deinococcus radiodurans R1 and Deinococcus geothermalis DSM 11300. Gene expression and disruption experiments demonstrated that dr0091 and dgeo2309 encode CruF in D. radiodurans and D. geothermalis, respectively. Their homologues were also found in the genomes of cyanobacteria, and exhibited little homology to the hydroxyneurosporene synthase (CrtC) proteins found mainly in photosynthetic bacteria. Phylogenetic analysis showed that CruF homologues form a separate family, which is evolutionarily distant from the known CrtC family.

  11. Bacteriophytochrome controls carotenoid-independent response to photodynamic stress in a non-photosynthetic rhizobacterium, Azospirillum brasilense Sp7.

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    Kumar, Santosh; Kateriya, Suneel; Singh, Vijay Shankar; Tanwar, Meenakshi; Agarwal, Shweta; Singh, Hina; Khurana, Jitendra Paul; Amla, Devinder Vijay; Tripathi, Anil Kumar

    2012-01-01

    Ever since the discovery of the role of bacteriophytochrome (BphP) in inducing carotenoid synthesis in Deinococcus radiodurans in response to light the role of BphPs in other non-photosynthetic bacteria is not clear yet. Azospirillum brasilense, a non-photosynthetic rhizobacterium, harbours a pair of BphPs out of which AbBphP1 is a homolog of AtBphP1 of Agrobacterium tumefaciens. By overexpression, purification, biochemical and spectral characterization we have shown that AbBphP1 is a photochromic bacteriophytochrome. Phenotypic study of the ΔAbBphP1 mutant showed that it is required for the survival of A. brasilense on minimal medium under red light. The mutant also showed reduced chemotaxis towards dicarboxylates and increased sensitivity to the photooxidative stress. Unlike D. radiodurans, AbBphP1 was not involved in controlling carotenoid synthesis. Proteome analysis of the ΔAbBphP1 indicated that AbBphP1 is involved in inducing a cellular response that enables A. brasilense in regenerating proteins that might be damaged due to photodynamic stress.

  12. Succession of cable bacteria and electric currents in marine sediment

    OpenAIRE

    Schauer, Regina; Risgaard-Petersen, Nils; Kjeldsen, Kasper U.; Tataru Bjerg, Jesper J; B Jørgensen, Bo; Schramm, Andreas; Nielsen, Lars Peter

    2014-01-01

    Filamentous Desulfobulbaceae have been reported to conduct electrons over centimetre-long distances, thereby coupling oxygen reduction at the surface of marine sediment to sulphide oxidation in sub-surface layers. To understand how these ‘cable bacteria' establish and sustain electric conductivity, we followed a population for 53 days after exposing sulphidic sediment with initially no detectable filaments to oxygen. After 10 days, cable bacteria and electric currents were established through...

  13. Estimating Achievable Accuracy for Global Imaging Spectroscopy Measurement of Non-Photosynthetic Vegetation Cover

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    Dennison, P. E.; Kokaly, R. F.; Daughtry, C. S. T.; Roberts, D. A.; Thompson, D. R.; Chambers, J. Q.; Nagler, P. L.; Okin, G. S.; Scarth, P.

    2016-12-01

    Terrestrial vegetation is dynamic, expressing seasonal, annual, and long-term changes in response to climate and disturbance. Phenology and disturbance (e.g. drought, insect attack, and wildfire) can result in a transition from photosynthesizing "green" vegetation to non-photosynthetic vegetation (NPV). NPV cover can include dead and senescent vegetation, plant litter, agricultural residues, and non-photosynthesizing stem tissue. NPV cover is poorly captured by conventional remote sensing vegetation indices, but it is readily separable from substrate cover based on spectral absorption features in the shortwave infrared. We will present past research motivating the need for global NPV measurements, establishing that mapping seasonal NPV cover is critical for improving our understanding of ecosystem function and carbon dynamics. We will also present new research that helps determine a best achievable accuracy for NPV cover estimation. To test the sensitivity of different NPV cover estimation methods, we simulated satellite imaging spectrometer data using field spectra collected over mixtures of NPV, green vegetation, and soil substrate. We incorporated atmospheric transmittance and modeled sensor noise to create simulated spectra with spectral resolutions ranging from 10 to 30 nm. We applied multiple methods of NPV estimation to the simulated spectra, including spectral indices, spectral feature analysis, multiple endmember spectral mixture analysis, and partial least squares regression, and compared the accuracy and bias of each method. These results prescribe sensor characteristics for an imaging spectrometer mission with NPV measurement capabilities, as well as a "Quantified Earth Science Objective" for global measurement of NPV cover. Copyright 2016, all rights reserved.

  14. A plastid gene phylogeny of the non-photosynthetic parasitic Orobanche (Orobanchaceae) and related genera

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    Park, J.-M.; Manen, J.-F.; Colwell, A.E.; Schneeweiss, G.M.

    2008-01-01

    The phylogenetic relationships of the non-photosynthetic Orobanche sensu lato (Orobanchaceae), which includes some of the economically most important parasitic weeds, remain insufficiently understood and controversial. This concerns both the phylogenetic relationships within the genus, in particular its monophyly or lack thereof, and the relationships to other holoparasitic genera such as Cistanche or Conopholis. Here we present the first comprehensive phylogenetic study of this group based on a region from the plastid genome (rps2 gene). Although substitution rates appear to be elevated compared to the photosynthetic members of Orobanchaceae, relationships among the major lineages Cistanche, Conopholis plus Epifagus, Boschniakia rossica (Cham. & Schltdl.) B. Fedtsch., B. himalaica Hook. f. & Thomson, B. hookeri Walp. plus B. strobilacea A. Gray, and Orobanche s. l. remain unresolved. Resolution within Orobanche, however, is much better. In agreement with morphological, cytological and other molecular phylogenetic evidence, five lineages, corresponding to the four traditionally recognised sections (Gymnocaulis, Myzorrhiza, Orobanche, Trionychon) and O. latisquama Reut. ex Boiss. (of sect. Orobanche), can be distinguished. A combined analysis of plastid rps2 and nuclear ITS sequences of the holoparasitic genera results in more resolved and better supported trees, although the relationships among Orobanche s. l., Cistanche, and the clade including the remaining genera is unresolved. Therefore, rps2 is a marker from the plastid genome that is well-suited to be used in combination with other already established nuclear markers for resolving generic relationships of Orobanche and related genera. ?? 2008 The Botanical Society of Japan and Springer.

  15. The Non-Photosynthetic Algae Helicosporidium spp.: Emergence of a Novel Group of Insect Pathogens

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    Aurélien Tartar

    2013-07-01

    Full Text Available Since the original description of Helicosporidium parasiticum in 1921, members of the genus Helicosporidium have been reported to infect a wide variety of invertebrates, but their characterization has remained dependent on occasional reports of infection. Recently, several new Helicosporidium isolates have been successfully maintained in axenic cultures. The ability to produce large quantity of biological material has led to very significant advances in the understanding of Helicosporidium biology and its interactions with insect hosts. In particular, the unique infectious process has been well documented; the highly characteristic cyst and its included filamentous cell have been shown to play a central role during host infection and have been the focus of detailed morphological and developmental studies. In addition, phylogenetic analyses inferred from a multitude of molecular sequences have demonstrated that Helicosporidium are highly specialized non-photosynthetic algae (Chlorophyta: Trebouxiophyceae, and represent the first described entomopathogenic algae. This review provides an overview of (i the morphology of Helicosporidium cell types, (ii the Helicosporidium life cycle, including the entire infectious sequence and its impact on insect hosts, (iii the phylogenetic analyses that have prompted the taxonomic classification of Helicosporidium as green algae, and (iv the documented host range for this novel group of entomopathogens.

  16. Immunocytochemical localization of Pisum sativum TRXs f and m in non-photosynthetic tissues.

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    Traverso, José A; Vignols, Florence; Cazalis, Roland; Serrato, Antonio J; Pulido, Pablo; Sahrawy, Mariam; Meyer, Yves; Cejudo, Francisco Javier; Chueca, Ana

    2008-01-01

    Plants are the organisms containing the most complex multigenic family for thioredoxins (TRX). Several types of TRXs are targeted to chloroplasts, which have been classified into four subgroups: m, f, x, and y. Among them, TRXs f and m were the first plastidial TRXs characterized, and their function as redox modulators of enzymes involved in carbon assimilation in the chloroplast has been well-established. Both TRXs, f and m, were named according to their ability to reduce plastidial fructose-1,6-bisphosphatase (FBPase) and malate dehydrogenase (MDH), respectively. Evidence is presented here based on the immunocytochemistry of the localization of f and m-type TRXs from Pisum sativum in non-photosynthetic tissues. Both TRXs showed a different spatial pattern. Whilst PsTRXm was localized to vascular tissues of all the organs analysed (leaves, stems, and roots), PsTRXf was localized to more specific cells next to xylem vessels and vascular cambium. Heterologous complementation analysis of the yeast mutant EMY63, deficient in both yeast TRXs, by the pea plastidial TRXs suggests that PsTRXm, but not PsTRXf, is involved in the mechanism of reactive oxygen species (ROS) detoxification. In agreement with this function, the PsTRXm gene was induced in roots of pea plants in response to hydrogen peroxide.

  17. Synergy in Sulfur Cycle: The Biogeochemical Significance of Sulfate Reducing Bacteria in Syntrophic Associations

    Digital Repository Service at National Institute of Oceanography (India)

    LokaBharathi, P.A.

    . In the gutless marine oligochaete Olavius algarvensis, endosymbiotic sulfate-reducing bacteria produce sulphide that can serve as an energy source for sulphide-oxidizing symbionts of the host. Apparently these symbionts do not compete for resources but rather... to tame and harness their potential better- from the coastal realms where they compete successfully with aerobes 33 in the biodegradative processes to the dark abysses of deep ocean beds where they biogeochemically control the rich mineral resources...

  18. RpoH2 sigma factor controls the photooxidative stress response in a non-photosynthetic rhizobacterium, Azospirillum brasilense Sp7.

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    Kumar, Santosh; Rai, Ashutosh Kumar; Mishra, Mukti Nath; Shukla, Mansi; Singh, Pradhyumna Kumar; Tripathi, Anil Kumar

    2012-12-01

    Bacteria belonging to the Alphaproteobacteria normally harbour multiple copies of the heat shock sigma factor (known as σ(32), σ(H) or RpoH). Azospirillum brasilense, a non-photosynthetic rhizobacterium, harbours five copies of rpoH genes, one of which is an rpoH2 homologue. The genes around the rpoH2 locus in A. brasilense show synteny with that found in rhizobia. The rpoH2 of A. brasilense was able to complement the temperature-sensitive phenotype of the Escherichia coli rpoH mutant. Inactivation of rpoH2 in A. brasilense results in increased sensitivity to methylene blue and to triphenyl tetrazolium chloride (TTC). Exposure of A. brasilense to TTC and the singlet oxygen-generating agent methylene blue induced several-fold higher expression of rpoH2. Comparison of the proteome of A. brasilense with its rpoH2 deletion mutant and with an A. brasilense strain overexpressing rpoH2 revealed chaperone GroEL, elongation factors (Ef-Tu and EF-G), peptidyl prolyl isomerase, and peptide methionine sulfoxide reductase as the major proteins whose expression was controlled by RpoH2. Here, we show that the RpoH2 sigma factor-controlled photooxidative stress response in A. brasilense is similar to that in the photosynthetic bacterium Rhodobacter sphaeroides, but that RpoH2 is not involved in the detoxification of methylglyoxal in A. brasilense.

  19. Succession of cable bacteria and electric currents in marine sediment.

    Science.gov (United States)

    Schauer, Regina; Risgaard-Petersen, Nils; Kjeldsen, Kasper U; Tataru Bjerg, Jesper J; B Jørgensen, Bo; Schramm, Andreas; Nielsen, Lars Peter

    2014-06-01

    Filamentous Desulfobulbaceae have been reported to conduct electrons over centimetre-long distances, thereby coupling oxygen reduction at the surface of marine sediment to sulphide oxidation in sub-surface layers. To understand how these 'cable bacteria' establish and sustain electric conductivity, we followed a population for 53 days after exposing sulphidic sediment with initially no detectable filaments to oxygen. After 10 days, cable bacteria and electric currents were established throughout the top 15 mm of the sediment, and after 21 days the filament density peaked with a total length of 2 km cm(-2). Cells elongated and divided at all depths with doubling times over the first 10 days of 98%. Comparison of the increase in biovolume and electric current density suggested high cellular growth efficiency. While the vertical expansion of filaments continued over time and reached 30 mm, the electric current density and biomass declined after 13 and 21 days, respectively. This might reflect a breakdown of short filaments as their solid sulphide sources became depleted in the top layers of the anoxic zone. In conclusion, cable bacteria combine rapid and efficient growth with oriented movement to establish and exploit the spatially separated half-reactions of sulphide oxidation and oxygen consumption.

  20. Late Proterozoic rise in atmospheric oxygen concentration inferred from phylogenetic and sulphur-isotope studies

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    Canfield, D. E.; Teske, A.

    1996-01-01

    The evolution of non-photosynthetic sulphide-oxidizing bacteria was contemporaneous with a large shift in the isotopic composition of biogenic sedimentary sulphides between 0.64 and 1.05 billion years ago. Both events were probably driven by a rise in atmospheric oxygen concentrations to greater than 5-18% of present levels--a change that may also have triggered the evolution of animals.

  1. RuBisCO in Non-Photosynthetic Alga Euglena longa: Divergent Features, Transcriptomic Analysis and Regulation of Complex Formation.

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    Kristína Záhonová

    Full Text Available Euglena longa, a close relative of the photosynthetic model alga Euglena gracilis, possesses an enigmatic non-photosynthetic plastid. Its genome has retained a gene for the large subunit of the enzyme RuBisCO (rbcL. Here we provide new data illuminating the putative role of RuBisCO in E. longa. We demonstrated that the E. longa RBCL protein sequence is extremely divergent compared to its homologs from the photosynthetic relatives, suggesting a possible functional shift upon the loss of photosynthesis. Similarly to E. gracilis, E. longa harbors a nuclear gene encoding the small subunit of RuBisCO (RBCS as a precursor polyprotein comprising multiple RBCS repeats, but one of them is highly divergent. Both RBCL and the RBCS proteins are synthesized in E. longa, but their abundance is very low compared to E. gracilis. No RBCS monomers could be detected in E. longa, suggesting that processing of the precursor polyprotein is inefficient in this species. The abundance of RBCS is regulated post-transcriptionally. Indeed, blocking the cytoplasmic translation by cycloheximide has no immediate effect on the RBCS stability in photosynthetically grown E. gracilis, but in E. longa, the protein is rapidly degraded. Altogether, our results revealed signatures of evolutionary degradation (becoming defunct of RuBisCO in E. longa and suggest that its biological role in this species may be rather unorthodox, if any.

  2. RuBisCO in Non-Photosynthetic Alga Euglena longa: Divergent Features, Transcriptomic Analysis and Regulation of Complex Formation

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    Záhonová, Kristína; Füssy, Zoltán; Oborník, Miroslav; Eliáš, Marek

    2016-01-01

    Euglena longa, a close relative of the photosynthetic model alga Euglena gracilis, possesses an enigmatic non-photosynthetic plastid. Its genome has retained a gene for the large subunit of the enzyme RuBisCO (rbcL). Here we provide new data illuminating the putative role of RuBisCO in E. longa. We demonstrated that the E. longa RBCL protein sequence is extremely divergent compared to its homologs from the photosynthetic relatives, suggesting a possible functional shift upon the loss of photosynthesis. Similarly to E. gracilis, E. longa harbors a nuclear gene encoding the small subunit of RuBisCO (RBCS) as a precursor polyprotein comprising multiple RBCS repeats, but one of them is highly divergent. Both RBCL and the RBCS proteins are synthesized in E. longa, but their abundance is very low compared to E. gracilis. No RBCS monomers could be detected in E. longa, suggesting that processing of the precursor polyprotein is inefficient in this species. The abundance of RBCS is regulated post-transcriptionally. Indeed, blocking the cytoplasmic translation by cycloheximide has no immediate effect on the RBCS stability in photosynthetically grown E. gracilis, but in E. longa, the protein is rapidly degraded. Altogether, our results revealed signatures of evolutionary degradation (becoming defunct) of RuBisCO in E. longa and suggest that its biological role in this species may be rather unorthodox, if any. PMID:27391690

  3. Accounting for non-photosynthetic vegetation in remote-sensing-based estimates of carbon flux in wetlands

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    Schile, Lisa M.; Byrd, Kristin B.; Windham-Myers, Lisamarie; Kelly, Maggi

    2013-01-01

    Monitoring productivity in coastal wetlands is important due to their high carbon sequestration rates and potential role in climate change mitigation. We tested agricultural- and forest-based methods for estimating the fraction of absorbed photosynthetically active radiation (f APAR), a key parameter for modelling gross primary productivity (GPP), in a restored, managed wetland with a dense litter layer of non-photosynthetic vegetation, and we compared the difference in canopy light transmission between a tidally influenced wetland and the managed wetland. The presence of litter reduced correlations between spectral vegetation indices and f APAR. In the managed wetland, a two-band vegetation index incorporating simulated World View-2 or Hyperion green and near-infrared bands, collected with a field spectroradiometer, significantly correlated with f APAR only when measured above the litter layer, not at the ground where measurements typically occur. Measures of GPP in these systems are difficult to capture via remote sensing, and require an investment of sampling effort, practical methods for measuring green leaf area and accounting for background effects of litter and water.

  4. Succession of cable bacteria and electric currents in marine sediment

    DEFF Research Database (Denmark)

    Schauer, Regina; Risgaard-Petersen, Nils; Kjeldsen, Kasper Urup

    2014-01-01

    ][mu]m, with a general increase over time and depth, and yet they shared 16S rRNA sequence identity of >98%. Comparison of the increase in biovolume and electric current density suggested high cellular growth efficiency. While the vertical expansion of filaments continued over time and reached 30[thinsp]mm, the electric......Filamentous Desulfobulbaceae have been reported to conduct electrons over centimetre-long distances, thereby coupling oxygen reduction at the surface of marine sediment to sulphide oxidation in sub-surface layers. To understand how these /`cable bacteria/' establish and sustain electric...... conductivity, we followed a population for 53 days after exposing sulphidic sediment with initially no detectable filaments to oxygen. After 10 days, cable bacteria and electric currents were established throughout the top 15[thinsp]mm of the sediment, and after 21 days the filament density peaked with a total...

  5. Succession of cable bacteria and electric currents in marine sediment

    DEFF Research Database (Denmark)

    Schauer, Regina; Risgaard-Petersen, Nils; Kjeldsen, Kasper Urup

    2014-01-01

    Filamentous Desulfobulbaceae have been reported to conduct electrons over centimetre-long distances, thereby coupling oxygen reduction at the surface of marine sediment to sulphide oxidation in sub-surface layers. To understand how these /`cable bacteria/' establish and sustain electric...... conductivity, we followed a population for 53 days after exposing sulphidic sediment with initially no detectable filaments to oxygen. After 10 days, cable bacteria and electric currents were established throughout the top 15[thinsp]mm of the sediment, and after 21 days the filament density peaked with a total......][mu]m, with a general increase over time and depth, and yet they shared 16S rRNA sequence identity of >98%. Comparison of the increase in biovolume and electric current density suggested high cellular growth efficiency. While the vertical expansion of filaments continued over time and reached 30[thinsp]mm, the electric...

  6. Innovative Approaches Using Lichen Enriched Media to Improve Isolation and Culturability of Lichen Associated Bacteria

    OpenAIRE

    Biosca, Elena G.; Flores, Raquel; Ricardo D Santander; D?ez-Gil, Jos? Luis; Barreno, Eva

    2016-01-01

    Lichens, self-supporting mutualistic associations between a fungal partner and one or more photosynthetic partners, also harbor non-photosynthetic bacteria. The diversity and contribution of these bacteria to the functioning of lichen symbiosis have recently begun to be studied, often by culture-independent techniques due to difficulties in their isolation and culture. However, culturing as yet unculturable lichenic bacteria is critical to unravel their potential functional roles in lichen sy...

  7. cDNA cloning, expression levels and gene mapping of photosynthetic and non-photosynthetic ferredoxin genes in sunflower (Helianthus annuus L.).

    Science.gov (United States)

    Venegas-Calerón, M; Zambelli, A; Ruiz-López, N; Youssar, L; León, A; Garcés, R; Martínez-Force, Enrique

    2009-03-01

    Fatty acid desaturation in plastids and chloroplasts depends on the electron-donor activity of ferredoxins. Using degenerate oligonucleotides designed from known photosynthetic and heterotrophic plant ferredoxin sequences, two full-length ferredoxin cDNAs were cloned from sunflower (Helianthus annuus L.) leaves and developing seeds, HaFd1 and HaFd2, homologous to photosynthetic and non-photosynthetic ferredoxins, respectively. Based on these cDNAs, the respective genomic sequences were obtained and the presence of DNA polymorphisms was investigated. Complete sequencing of the HaFd1 and HaFd2 genes in different lines indicated the presence of two haplotypes for HaFd2 and their alignment showed that sequence polymorphisms are restricted to the 5'-NTR intron. In addition, specific DNA markers for the HaFd1 and HaFd2 genes were developed that enabled the genes to be mapped. Accordingly, the HaFd1 locus maps to linkage group 10 of the public sunflower map, while the HaFd2 locus maps to linkage group 11. Both ferredoxins display different spatial-temporal patterns of expression. While HaFd2 is expressed at similar levels in all tissues tested (leaves, stem, roots, cotyledons and developing seeds), HaFd1 is more strongly expressed in green tissues than in all the other tissues tested. Both photosynthetic- and heterotrophic-ferredoxins are present in sunflower seeds and may contribute to fatty acid desaturation during oil accumulation. Nevertheless, the levels of HaFd2 expression during seed formation are distinct in lines that only varied in the HaFd2 haplotypes they expressed.

  8. Chemical behaviors of different arsenic-bearing sulphides bio-oxidated by thermophilic bacteria

    Institute of Scientific and Technical Information of China (English)

    YANG Hong-ying; GONG En-pu; YANG Li-li; WANG Da-wen

    2005-01-01

    The study on arsenopyrite and realgar of bacterial oxidation shows that the chemical behaviors of different arsenic-bearing sulphides oxidated by thermophilic bacteria are quite distinct. Arsenopyrite is active and quickly eroded in bacteria-bearing solution. With a high leaching rate over 95%, the arsenopyrite phase cannot be detected by X-ray diffraction(XRD). Arsenopyrite is highly toxic to bacteria that at the initial stage of bio-oxidation, bacterial growth is inhibited and the number of bacterium cell drops from 2.26 × 108/mL to the lowest 2.01 × 105/mL. At the later stages of bio-oxidation, bacteria grow fast and reach 2.23 × 108/mL. Comparably, realgar is inertial and resistive to bacterial corrosion and oxidation. Arsenic in realgar crystal is hard to be leached and the residue is still realgar phase, as indicated by XRD. The cell number of bacteria varies a little, decreasing from 2.26 × 108/mL to 2.01 × 107/mL, during the bacterial oxidation. The results show that the crystal structure and arsenic valency of arsenic-bearing sulphides play a vital role during the leaching process of bacterial oxidation.

  9. Characteristics of the temperature coefficlent,Q10,for the respiration of non-photosynthetic organs and soils of forest ecosystems

    Institute of Scientific and Technical Information of China (English)

    Wang Wenjie; Wang Huimei; Zu Yuangang; Li Xueying; Koike Takayoshi

    2006-01-01

    activity may be more sensitive to global warming.The duration of the period with leaves slightly affects the temperature sensitivity of woody organisms since the Q10 values for root and stem of coniferous evergreen trees did not differ significantly from deciduous trees (p>0.10). CO2 analytical methods (soda lime absorption method,IRGA (Infra-read gas analysis),and chromatograph analysis) and root separation methods (excised root and trenched box) slightly affected the Q10 values of soil and root respiration (p>0.10),but an in vitro measurement of stem respiration yielded a significantly higher Q10 value than an in vivo method (p<0.05).In general,although the Q10 values of non-photosynthetic organisms stayed within a relatively conservative range,considerable variation between and within elements were still detectable.Accordingly,attention should be paid to the quantitative estimation of total CO2 effiux by Q10-related models.In future studies,the biochemical factors and the environmental and biological factors controlling respiration should be emphasized for precise estimation of total CO2 effiux.The difficulty is how to clarify the underlying mechanism for fluctuations of Q10 values for one specific habitat and element (e.g.temperature acclimation or adaptation of Q10 values) and then allow the Q10 values to be more conservative for representation of temperature sensitivity in global warming processes.

  10. Estimating photosynthetic vegetation, non-photosynthetic vegetation and bare soil fractions using Landsat and MODIS data: Effects of site heterogeneity, soil properties and land cover

    Science.gov (United States)

    Guerschman, J. P.; Scarth, P.; McVicar, T.; Malthus, T. J.; Stewart, J.; Rickards, J.; Trevithick, R.; Renzullo, L. J.

    2013-12-01

    Vegetation fractional cover is a key indicator for land management monitoring, both in pastoral and agricultural settings. Maintaining adequate vegetation cover protects the soil from the effects of water and wind erosion and also ensures that carbon is returned to soil through decomposition. Monitoring vegetation fractional cover across large areas and continuously in time needs good remote sensing techniques underpinned by high quality ground data to calibrate and validate algorithms. In this study we used Landsat and MODIS reflectance data together with field measurements from 1476 observations across Australia to produce estimates of vegetation fractional cover using a linear unmixing technique. Specifically, we aimed at separating fractions of photosynthetic vegetation (PV), non-photosynthetic vegetation (NPV) and bare soil (B). We used Landsat reflectance averaged over a 3x3 pixel window representing the area actually measured on the ground and also a 'degraded' Landsat reflectance 40x40 pixel window to simulate the effect of a coarser sensor. Using these two Landsat reflectances we quantified the heterogeneity of each site. We used data from two MODIS-derived reflectance products: the Nadir BRDF-Adjusted surface Reflectance product (MCD43A4) and the MODIS 8-day surface reflectance (MOD09A1). We derived endmembers from the data and estimated fractional cover using a linear unmixing technique. Log transforms and band interaction terms were added to account for non-linearities in the spectral mixing. For each reflectance source we investigated if the residuals were correlated with site heterogeneity, soil colour, soil moisture and land cover type. As expected, the best model was obtained when Landsat data for a small region around each site was used. We obtained root mean square error (RMSE) values of 0.134, 0.175 and 0.153 for PV, NPV and B respectively. When we degraded the Landsat data to an area of ~1 km2 around each site the model performance decreased to

  11. Sulphide oxidation in ornamental slates: protective treatment with siloxanes

    OpenAIRE

    Rivas, T.; Iglesias, J.; Taboada, J.; Vilán, J.A.

    2011-01-01

    In this work, we present the results of the measurement of the effectiveness of two silanes-siloxanes based products applied on roofing slates with the aim of slowing down the oxidation of the iron sulphide inclusions. The products were applied by immersion and spraying and also at different dilutions. The effectiveness of the treatments were evaluated by means of static contact angle measurements and water absorption coefficient variations; also, the durability under thermal cycles and the c...

  12. Sulphide oxidation in ornamental slates: protective treatment with siloxanes

    Directory of Open Access Journals (Sweden)

    Rivas, T.

    2011-03-01

    Full Text Available In this work, we present the results of the measurement of the effectiveness of two silanes-siloxanes based products applied on roofing slates with the aim of slowing down the oxidation of the iron sulphide inclusions. The products were applied by immersion and spraying and also at different dilutions. The effectiveness of the treatments were evaluated by means of static contact angle measurements and water absorption coefficient variations; also, the durability under thermal cycles and the colour variations before treatment and before UVA exposition were tested. In all the cases, a very low product consumptions were obtained, due to the particular porous system of these rocks; also, any of the treatments increased the static angle. Nevertheless, the products tested remarkably increased the resistance of sulphides to the oxidation during thermal cycles without producing important changes in rock colour and also they have shown a good durability under UVA exposition

    En este trabajo se presentan los resultados de la medida de la eficacia de dos silanos-siloxanos aplicados en pizarras de techar con el objetivo de reducir la oxidación de las inclusiones de sulfuros de hierro. Los productos fueron aplicados por inmersión y spray a diferentes concentraciones. La efectividad de los tratamientos fue evaluada mediante la medida del ángulo de contacto estático y las variaciones del coeficiente de absorción de agua y su durabilidad mediante ciclos térmicos y de exposición a luz ultravioleta. A pesar del bajo consumo de ambos productos, debido al particular sistema poroso de estas rocas, y del bajo incremento del ángulo de contacto, ambos silanos-siloxanos incrementan notablemente la resistencia de los sulfuros a la oxidación durante los ciclos térmicos sin producir cambios relevantes en el color de la roca y muestran una aceptable durabilidad bajo la luz ultravioleta.

  13. Biomarker evidence for green and purple sulphur bacteria in a stratified Palaeoproterozoic sea.

    Science.gov (United States)

    Brocks, Jochen J; Love, Gordon D; Summons, Roger E; Knoll, Andrew H; Logan, Graham A; Bowden, Stephen A

    2005-10-06

    The disappearance of iron formations from the geological record approximately 1.8 billion years (Gyr) ago was the consequence of rising oxygen levels in the atmosphere starting 2.45-2.32 Gyr ago. It marks the end of a 2.5-Gyr period dominated by anoxic and iron-rich deep oceans. However, despite rising oxygen levels and a concomitant increase in marine sulphate concentration, related to enhanced sulphide oxidation during continental weathering, the chemistry of the oceans in the following mid-Proterozoic interval (approximately 1.8-0.8 Gyr ago) probably did not yet resemble our oxygen-rich modern oceans. Recent data indicate that marine oxygen and sulphate concentrations may have remained well below current levels during this period, with one model indicating that anoxic and sulphidic marine basins were widespread, and perhaps even globally distributed. Here we present hydrocarbon biomarkers (molecular fossils) from a 1.64-Gyr-old basin in northern Australia, revealing the ecological structure of mid-Proterozoic marine communities. The biomarkers signify a marine basin with anoxic, sulphidic, sulphate-poor and permanently stratified deep waters, hostile to eukaryotic algae. Phototrophic purple sulphur bacteria (Chromatiaceae) were detected in the geological record based on the new carotenoid biomarker okenane, and they seem to have co-existed with communities of green sulphur bacteria (Chlorobiaceae). Collectively, the biomarkers support mounting evidence for a long-lasting Proterozoic world in which oxygen levels remained well below modern levels.

  14. The Type III Secretion System (T3SS) is a Determinant for Rice-Endophyte Colonization by Non-Photosynthetic Bradyrhizobium.

    Science.gov (United States)

    Piromyou, Pongdet; Songwattana, Pongpan; Greetatorn, Teerana; Okubo, Takashi; Kakizaki, Kaori Chiba; Prakamhang, Janpen; Tittabutr, Panlada; Boonkerd, Nantakorn; Teaumroong, Neung; Minamisawa, Kiwamu

    2015-01-01

    Plant associations by bradyrhizobia have been detected not only in leguminous plants, but also in non-leguminous species including rice. Bradyrhizobium sp. SUTN9-2 was isolated from Aeschynomene americana L., which is a leguminous weed found in the rice fields of Thailand. This strain promoted the highest total rice (Oryza sativa L. cultivar Pathum Thani 1) dry weight among the endophytic bradyrhizobial strains tested, and was, thus, employed for the further characterization of rice-Bradyrhizobium interactions. Some known bacterial genes involved in bacteria-plant interactions were selected. The expression of the type III secretion component (rhcJ), type IV secretion component (virD4), and pectinesterase (peces) genes of the bacterium were up-regulated when the rice root exudate was added to the culture. When SUTN9-2 was inoculated into rice seedlings, the peces, rhcJ, virD4, and exopolysaccharide production (fliP) genes were strongly expressed in the bacterium 6-24 h after the inoculation. The gene for glutathione-S-transferase (gst) was slightly expressed 12 h after the inoculation. In order to determine whether type III secretion system (T3SS) is involved in bradyrhizobial infections in rice plants, wild-type SUTN9-2 and T3SS mutant strains were inoculated into the original host plant (A. americana) and a rice plant (cultivar Pathum Thani 1). The ability of T3SS mutants to invade rice tissues was weaker than that of the wild-type strain; however, their phenotypes in A. americana were not changed by T3SS mutations. These results suggest that T3SS is one of the important determinants modulating rice infection; however, type IV secretion system and peces may also be responsible for the early steps of rice infection.

  15. FtsZ-less prokaryotic cell division as well as FtsZ- and dynamin-less chloroplast and non-photosynthetic plastid division

    Directory of Open Access Journals (Sweden)

    Shin-Ya eMiyagishima

    2014-09-01

    Full Text Available The chloroplast division machinery is a mixture of a stromal FtsZ-based complex descended from a cyanobacterial ancestor of chloroplasts and a cytosolic dynamin-related protein (DRP 5B-based complex derived from the eukaryotic host. Molecular genetic studies have shown that each component of the division machinery is normally essential for normal chloroplast division. However, several exceptions have been found. In the absence of the FtsZ ring, nonphotosynthetic plastids are able to proliferate, likely by elongation and budding. Depletion of DRP5B impairs, but does not stop chloroplast division. Chloroplasts in glaucophytes, which possesses a peptidoglycan (PG layer, divide without DRP5B. Certain parasitic eukaryotes possess nonphotosynthetic plastids of secondary endosymbiotic origin, but neither FtsZ nor DRP5B is encoded in their genomes. Elucidation of the FtsZ- and/or DRP5B-less chloroplast division mechanism will lead to a better understanding of the function and evolution of the chloroplast division machinery and the finding of the as-yet-unknown mechanism that is likely involved in chloroplast division. Recent studies have shown that FtsZ was lost from a variety of prokaryotes, many of which lost PG by regressive evolution. In addition, even some of the FtsZ-bearing bacteria are able to divide when FtsZ and PG are depleted experimentally. In some cases, alternative mechanisms for cell division, such as budding by an increase of the cell surface-to-volume ratio, are proposed. Although PG is believed to have been lost from chloroplasts other than in glaucophytes, there is some indirect evidence for the existence of PG in chloroplasts. Such information is also useful for understanding how nonphotosynthetic plastids are able to divide in FtsZ-depleted cells and the reason for the retention of FtsZ in chloroplast division. Here we summarize information to facilitate analyses of FtsZ- and/or DRP5B-less chloroplast and nonphotosynthetic plastid

  16. Sulphur-cycling bacteria and ciliated protozoans in a Beggiatoaceae mat covering organically enriched sediments beneath a salmon farm in a southern Chilean fjord.

    Science.gov (United States)

    Aranda, Carlos P; Valenzuela, Cristian; Matamala, Yessica; Godoy, Félix A; Aranda, Nicol

    2015-11-15

    The colourless mat covering organically enriched sediments underlying an intensive salmon farm in Estero Pichicolo, southern Chile, was surveyed by combined 454 PyroTag and conventional Sanger sequencing of 16S/18S ribosomal RNA genes for Bacteria and Eukarya. The mat was dominated by the sulphide-oxidizing bacteria (SOB) Candidatus Isobeggiatoa, Candidatus Parabeggiatoa and Arcobacter. By order of their abundances, sulphate-reducing bacteria (SRB) were represented by diverse deltaproteobacterial Desulfobacteraceae, but also within Desulfobulbaceae, Desulfuromonadaceae and Desulfovibrionaceae. The eukaryotic PyroTags were dominated by polychaetes, copepods and nematodes, however, ciliated protozoans were highly abundant in microscopy observations, and were represented by the genera Condylostoma, Loxophyllum and Peritromus. Finally, the abundant Sulfurimonas/Sulfurovum also suggest the occurrence of zero-valence sulphur oxidation, probably derived from Beggiatoaceae as a result of bacteriovorus infaunal activity or generated as free S(0) by the Arcobacter bacteria. The survey suggests an intense and complex sulphur cycle within the surface of salmon-farm impacted sediments.

  17. Early oxygenation of the terrestrial environment during the Mesoproterozoic.

    Science.gov (United States)

    Parnell, John; Boyce, Adrian J; Mark, Darren; Bowden, Stephen; Spinks, Sam

    2010-11-11

    Geochemical data from ancient sedimentary successions provide evidence for the progressive evolution of Earth's atmosphere and oceans. Key stages in increasing oxygenation are postulated for the Palaeoproterozoic era (∼2.3 billion years ago, Gyr ago) and the late Proterozoic eon (about 0.8 Gyr ago), with the latter implicated in the subsequent metazoan evolutionary expansion. In support of this rise in oxygen concentrations, a large database shows a marked change in the bacterially mediated fractionation of seawater sulphate to sulphide of Δ(34)S atmospheric oxygen concentrations and the evolution of non-photosynthetic sulphide-oxidizing bacteria. Here we report Δ(34)S values exceeding 50‰ from a terrestrial Mesoproterozoic (1.18 Gyr old) succession in Scotland, a time period that is at present poorly characterized. This level of fractionation implies disproportionation in the sulphur cycle, probably involving sulphide-oxidizing bacteria, that is not evident from Δ(34)S data in the marine record. Disproportionation in both red beds and lacustrine black shales at our study site suggests that the Mesoproterozoic terrestrial environment was sufficiently oxygenated to support a biota that was adapted to an oxygen-rich atmosphere, but had also penetrated into subsurface sediment.

  18. Growth of Chlorella vulgaris and associated bacteria in photobioreactors.

    Science.gov (United States)

    Lakaniemi, Aino-Maija; Intihar, Veera M; Tuovinen, Olli H; Puhakka, Jaakko A

    2012-01-01

    The aim of this study was to test three flat plate photobioreactor configurations for growth of Chlorella vulgaris under non-axenic conditions and to characterize and quantify associated bacterial communities. The photobioreactor cultivations were conducted using tap water-based media to introduce background bacterial population. Growth of algae was monitored over time with three independent methods. Additionally, the quantity and quality of eukaryotes and bacteria were analysed using culture-independent molecular tools based on denaturing gradient gel electrophoresis (PCR-DGGE) and quantitative polymerase chain reaction (QPCR). Static mixers used in the flat plate photobioreactors did not generally enhance the growth at the low light intensities used. The maximum biomass concentration and maximum specific growth rate were 1.0 g l(-1) and 2.0 day(-1) respectively. Bacterial growth as determined by QPCR was associated with the growth of C. vulgaris. Based on PCR-DGGE, bacteria in the cultures mainly originated from the tap water. Bacterial community profiles were diverse but reproducible in all flat plate cultures. Most prominent bacteria in the C. vulgaris cultures belonged to the class Alphaproteobacteria and especially to the genus Sphingomonas. Analysis of the diversity of non-photosynthetic microorganisms in algal mass cultures can provide useful information on the public health aspects and unravel community interactions.

  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. Anaerobic bacteria

    Science.gov (United States)

    Brook I, Goldstein EJ. Diseases caused by non-spore forming anaerobic bacteria. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 297. Stedman's Online ...

  1. Pathway of Fermentative Hydrogen Production by Sulfate-reducing Bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Wall, Judy D. [Univ. of Missouri, Columbia, MO (United States)

    2015-02-16

    Biofuels are a promising source of sustainable energy. Such biofuels are intermediate products of microbial metabolism of renewable substrates, in particular, plant biomass. Not only are alcohols and solvents produced in this degradative process but energy-rich hydrogen as well. Non photosynthetic microbial hydrogen generation from compounds other than sugars has not been fully explored. We propose to examine the capacity of the abundant soil anaerobes, sulfate-reducing bacteria, for hydrogen generation from organic acids. These apparently simple pathways have yet to be clearly established. Information obtained may facilitate the exploitation of other microbes not yet readily examined by molecular tools. Identification of the flexibility of the metabolic processes to channel reductant to hydrogen will be useful in consideration of practical applications. Because the tools for genetic and molecular manipulation of sulfate-reducing bacteria of the genus Desulfovibrio are developed, our efforts will focus on two strains, D. vulgaris Hildenborough and Desulfovibrio G20.Therefore total metabolism, flux through the pathways, and regulation are likely to be limiting factors which we can elucidate in the following experiments.

  2. Big bacteria

    DEFF Research Database (Denmark)

    Schulz, HN; Jørgensen, BB

    2001-01-01

    , 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......, 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...

  3. Pigments from UV-resistant Antarctic bacteria as photosensitizers in Dye Sensitized Solar Cells.

    Science.gov (United States)

    Órdenes-Aenishanslins, N; Anziani-Ostuni, G; Vargas-Reyes, M; Alarcón, J; Tello, A; Pérez-Donoso, J M

    2016-09-01

    Here we report the use of pigments produced by UV-resistant Antarctic bacteria as photosensitizers in Dye Sensitized Solar Cells (DSSCs). Pigments were obtained from red and yellow colored psychrotolerant bacteria isolated from soils of King George Island, Antarctica. Based on metabolic characteristics and 16s DNA sequence, pigmented bacteria were identified as Hymenobacter sp. (red) and Chryseobacterium sp. (yellow). Pigments produced by these microorganisms were extracted and classified as carotenoids based on their spectroscopic and structural characteristics, determined by UV-Vis spectrophotometry and infrared spectroscopy (FTIR), respectively. With the purpose of develop green solar cells based on bacterial pigments, the photostability and capacity of these molecules as light harvesters in DSSCs were determined. Absorbance decay assays determined that bacterial carotenoids present high photostability. In addition, solar cells based on these photosensitizers exhibit an open circuit voltage (VOC) of 435.0 [mV] and a short circuit current density (ISC) of 0.2 [mA·cm(-2)] for the red pigment, and a VOC of 548.8 [mV] and a ISC of 0.13 [mA·cm(-2)] for the yellow pigment. This work constitutes the first approximation of the use of pigments produced by non-photosynthetic bacteria as photosensitizers in DSSCs. Determined photochemical characteristics of bacterial pigments, summed to their easy obtention and low costs, validates its application as photosensitizers in next-generation biological solar cells.

  4. Innovative Approaches Using Lichen Enriched Media to Improve Isolation and Culturability of Lichen Associated Bacteria

    Science.gov (United States)

    Biosca, Elena G.; Flores, Raquel; Santander, Ricardo D.; Díez-Gil, José Luis; Barreno, Eva

    2016-01-01

    Lichens, self-supporting mutualistic associations between a fungal partner and one or more photosynthetic partners, also harbor non-photosynthetic bacteria. The diversity and contribution of these bacteria to the functioning of lichen symbiosis have recently begun to be studied, often by culture-independent techniques due to difficulties in their isolation and culture. However, culturing as yet unculturable lichenic bacteria is critical to unravel their potential functional roles in lichen symbiogenesis, to explore and exploit their biotechnological potential and for the description of new taxa. Our objective was to improve the recovery of lichen associated bacteria by developing novel isolation and culture approaches, initially using the lichen Pseudevernia furfuracea. We evaluated the effect of newly developed media enriched with novel lichen extracts, as well as the influence of thalli washing time and different disinfection and processing protocols of thalli. The developed methodology included: i) the use of lichen enriched media to mimic lichen nutrients, supplemented with the fungicide natamycin; ii) an extended washing of thalli to increase the recovery of ectolichenic bacteria, thus allowing the disinfection of thalli to be discarded, hence enhancing endolichenic bacteria recovery; and iii) the use of an antioxidant buffer to prevent or reduce oxidative stress during thalli disruption. The optimized methodology allowed significant increases in the number and diversity of culturable bacteria associated with P. furfuracea, and it was also successfully applied to the lichens Ramalina farinacea and Parmotrema pseudotinctorum. Furthermore, we provide, for the first time, data on the abundance of culturable ecto- and endolichenic bacteria that naturally colonize P. furfuracea, R. farinacea and P. pseudotinctorum, some of which were only able to grow on lichen enriched media. This innovative methodology is also applicable to other microorganisms inhabiting these

  5. Innovative Approaches Using Lichen Enriched Media to Improve Isolation and Culturability of Lichen Associated Bacteria.

    Science.gov (United States)

    Biosca, Elena G; Flores, Raquel; Santander, Ricardo D; Díez-Gil, José Luis; Barreno, Eva

    2016-01-01

    Lichens, self-supporting mutualistic associations between a fungal partner and one or more photosynthetic partners, also harbor non-photosynthetic bacteria. The diversity and contribution of these bacteria to the functioning of lichen symbiosis have recently begun to be studied, often by culture-independent techniques due to difficulties in their isolation and culture. However, culturing as yet unculturable lichenic bacteria is critical to unravel their potential functional roles in lichen symbiogenesis, to explore and exploit their biotechnological potential and for the description of new taxa. Our objective was to improve the recovery of lichen associated bacteria by developing novel isolation and culture approaches, initially using the lichen Pseudevernia furfuracea. We evaluated the effect of newly developed media enriched with novel lichen extracts, as well as the influence of thalli washing time and different disinfection and processing protocols of thalli. The developed methodology included: i) the use of lichen enriched media to mimic lichen nutrients, supplemented with the fungicide natamycin; ii) an extended washing of thalli to increase the recovery of ectolichenic bacteria, thus allowing the disinfection of thalli to be discarded, hence enhancing endolichenic bacteria recovery; and iii) the use of an antioxidant buffer to prevent or reduce oxidative stress during thalli disruption. The optimized methodology allowed significant increases in the number and diversity of culturable bacteria associated with P. furfuracea, and it was also successfully applied to the lichens Ramalina farinacea and Parmotrema pseudotinctorum. Furthermore, we provide, for the first time, data on the abundance of culturable ecto- and endolichenic bacteria that naturally colonize P. furfuracea, R. farinacea and P. pseudotinctorum, some of which were only able to grow on lichen enriched media. This innovative methodology is also applicable to other microorganisms inhabiting these

  6. Rhizosphere Bacteria

    Directory of Open Access Journals (Sweden)

    N.V. Feoktistova

    2016-06-01

    Full Text Available The review deals with the analysis of modern literature data on rhizosphere bacteria and their role in plant life. The structure of rhizosphere has been characterized. The role of plants as the centers of formation of microbial communities has been shown. Data on the main groups of microorganisms inhabiting the rhizosphere have been provided. The associative relationship between rhizobacteria and partner plants has been investigated. The modern concept of holobiont defined as the whole host plant organism and microorganisms associated with it has been reviewed. The role of rhizobacteria in the processes of nitrogen fixation has been discussed in detail. The mechanisms of direct stimulation of plant growth by biosynthesis of phytohormones, improvement of phosphorus and nitrogen nutrition, increase in resistance to stress, and stimulation mediated by antagonism against pathogenic microorganisms have been analyzed. The criteria for selection of rhizobacteria for practical purposes have been discussed.

  7. Influence of methanethiol on biological sulphide oxidation in gas treatment system.

    Science.gov (United States)

    Roman, Pawel; Bijmans, Martijn F M; Janssen, Albert J H

    2016-01-01

    Inorganic and organic sulphur compounds such as hydrogen sulphide (H2S) and thiols (RSH) are unwanted components in sour gas streams (e.g. biogas and refinery gases) because of their toxicity, corrosivity and bad smell. Biological treatment processes are often used to remove H2S at small and medium scales (<50 tons per day of H2S). Preliminarily research by our group focused on achieving maximum sulphur production from biological H2S oxidation in the presence of methanethiol. In this paper the underlying principles have been further studied by assessing the effect of methanethiol on the biological conversion of H2S under a wide range of redox conditions covering not only sulphur but also sulphate-producing conditions. Furthermore, our experiments were performed in an integrated system consisting of a gas absorber and a bioreactor in order to assess the effect of methanethiol on the overall gas treatment efficiency. This study shows that methanethiol inhibits the biological oxidation of H2S to sulphate by way of direct suppression of the cytochrome c oxidase activity in biomass, whereas the oxidation of H2S to sulphur was hardly affected. We estimated the kinetic parameters of biological H2S oxidation that can be used to develop a mathematical model to quantitatively describe the biodesulphurization process. Finally, it was found that methanethiol acts as a competitive inhibitor; therefore, its negative effect can be minimized by increasing the enzyme (biomass) concentration and the substrate (sulphide) concentration, which in practice means operating the biodesulphurization systems under low redox conditions.

  8. A note on sulphide-oxide mineralisation in Carlsberg Ridge basalts

    Digital Repository Service at National Institute of Oceanography (India)

    Banerjee, R.; Iyer, S.D.

    Pillow basalts from the Carlsberg Ridge at 3 degrees 35'N contain disseminated chalcopyrite, pyrite, and magnetite. The euhedral shape of the pyrite grains indicate them to be early formed and grown unobstructed while magnetite occurs as skeletal...

  9. Bacteria isolated from amoebae/bacteria consortium

    Science.gov (United States)

    Tyndall, Richard L.

    1995-01-01

    New protozoan derived microbial consortia and method for their isolation are provided. Consortia and bacteria isolated therefrom are useful for treating wastes such as trichloroethylene and trinitrotoluene. Consortia, bacteria isolated therefrom, and dispersants isolated therefrom are useful for dispersing hydrocarbons such as oil, creosote, wax, and grease.

  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. Intracellular Bacteria in Protozoa

    Science.gov (United States)

    Görtz, Hans-Dieter; Brigge, Theo

    Intracellular bacteria in humans are typically detrimental, and such infections are regarded by the patients as accidental and abnormal. In protozoa it seems obvious that many bacteria have coevolved with their hosts and are well adapted to the intracellular way of life. Manifold interactions between hosts and intracellular bacteria are found, and examples of antibacterial resistance of unknown mechanisms are observed. The wide diversity of intracellular bacteria in protozoa has become particularly obvious since they have begun to be classified by molecular techniques. Some of the bacteria are closely related to pathogens; others are responsible for the production of toxins.

  13. Using flow cytometry for counting natural planktonic bacteria and understanding the structure of planktonic bacterial communities

    Directory of Open Access Journals (Sweden)

    Josep M. Gasol

    2000-06-01

    Full Text Available Flow cytometry is rapidly becoming a routine methodology in aquatic microbial ecology. The combination of simple to use bench-top flow cytometers and highly fluorescent nucleic acid stains allows fast and easy determination of microbe abundance in the plankton of lakes and oceans. The different dyes and protocols used to stain and count planktonic bacteria as well as the equipment in use are reviewed, with special attention to some of the problems encountered in daily routine practice such as fixation, staining and absolute counting. One of the main advantages of flow cytometry over epifluorescence microscopy is the ability to obtain cell-specific measurements in large numbers of cells with limited effort. We discuss how this characteristic has been used for differentiating photosynthetic from non-photosynthetic prokaryotes, for measuring bacterial cell size and nucleic acid content, and for estimating the relative activity and physiological state of each cell. We also describe how some of the flow cytometrically obtained data can be used to characterize the role of microbes on carbon cycling in the aquatic environment and we prospect the likely avenues of progress in the study of planktonic prokaryotes through the use of flow cytometry.

  14. Carbon metabolic pathways in phototrophic bacteria and their broader evolutionary implications

    Directory of Open Access Journals (Sweden)

    Kuo-Hsiang eTang

    2011-08-01

    Full Text Available Photosynthesis is the biological process that converts solar energy to biomass, bio-products and biofuel. It is the only major natural solar energy storage mechanism on Earth. To satisfy the increased demand for sustainable energy sources and identify the mechanism of photosynthetic carbon assimilation, which is one of the bottlenecks in photosynthesis, it is essential to understand the process of solar energy storage and associated carbon metabolism in photosynthetic organisms. Researchers have employed physiological studies, microbiological chemistry, enzyme assays, genome sequencing, transcriptomics, and 13C-based metabolomics/fluxomics to investigate central carbon metabolism and enzymes that operate in phototrophs. In this report, we review diverse CO2 assimilation pathways, acetate assimilation, carbohydrate catabolism, the TCA cycle and some key and/or unconventional enzymes in central carbon metabolism of phototrophic microorganisms. We also discuss the reducing equivalent flow during photoautotrophic and photoheterotrophic growth, evolutionary links in the central carbon metabolic network, and correlations between photosynthetic and non-photosynthetic organisms. Considering the metabolic versatility in these fascinating and diverse photosynthetic bacteria, many essential questions in their central carbon metabolism still remain to be addressed.

  15. 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.

  16. How honey kills bacteria

    NARCIS (Netherlands)

    P.H.S. Kwakman; A.A. te Velde; L. de Boer; D. Speijer; C.M.J.E. Vandenbroucke-Grauls; S.A.J. Zaat

    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 t

  17. Metallization of bacteria cells

    Institute of Scientific and Technical Information of China (English)

    黎向锋; 李雅芹; 蔡军; 张德远

    2003-01-01

    Bacteria cells with different standard shapes are well suited for use as templates for the fabrication of magnetic and electrically conductive microstructures. In this paper, metallization of bacteria cells is demonstrated by an electroless deposition technique of nickel-phosphorus initiated by colloid palladium-tin catalyst on the surfaces of Citeromyces matritensis and Bacillus cereus. The activated and metallized bacteria cells have been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction analysis (XRD). Results showed that both Citeromyces matritensis and Bacillus cereus had no deformation in shape after metallization; the metallized films deposited on the surfaces of bacteria cells are homogeneous in thickness and noncrystalline in phase structure. The kinetics of colloid palladium-tin solution and electroless plating on bacteria cells is discussed.

  18. 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.

  19. [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.

  20. 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...

  1. Lipopolysaccharides in diazotrophic bacteria

    Directory of Open Access Journals (Sweden)

    Rodrigo Vassoler Serrato

    2014-09-01

    Full Text Available Biological nitrogen fixation 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.

  2. 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.

  3. 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.

  4. Technological investigations of sulphide oxidation from flotation tailings in order to increase the degree of copper leaching

    OpenAIRE

    Jonović, Radojka; Avramović, Ljiljana; Stevanović, Zoran; Jonović, Marko

    2014-01-01

    The off-balance resources present the environmental problem and potential resource for copper extraction. This paper presents the results obtained using different reagents for the process of sulphide form oxidation of copper from flotation tailings. For the investigation in this paper work, the samples of flotation tailings were taken from the Old Flotation Tailing Dump of the Mining and Smelting Complex Bor in Eastern Serbia. Experimental testing was carried out in order to increase the leac...

  5. Experimental and theoretical insights into the oxodiperoxomolybdenum-catalysed sulphide oxidation using hydrogen peroxide in ionic liquids.

    Science.gov (United States)

    Carrasco, Carlos J; Montilla, Francisco; Alvarez, Eleuterio; Mealli, Carlo; Manca, Gabriele; Galindo, Agustín

    2014-09-28

    The oxidation of organic sulphides with aqueous hydrogen peroxide in ionic liquids (ILs) catalysed by oxodiperoxomolybdenum complexes was investigated. The selective formation of several sulfones was achieved using the 1 : 3 ratio of sulphide : H2O2 in [C4mim][PF6] (C4mim = 1-butyl-3-methylimidazolium) in a reaction catalysed by the [Mo(O)(O2)2(H2O)n] complex. Conversely, sulfoxides were produced with good selectivities using a 1 : 1 ratio in the same solvent in a 1 h reaction with [Mo(O)(O2)2(Mepz)2] (Mepz = methylpyrazol). The use of [C4mim][PF6] as the solvent was advantageous for two reasons: (i) the improved performance of the H2O2-IL combination; (ii) recycling of the catalyst/IL mixture without a significant diminution of conversion or selectivity. A DFT analysis using the [Mo(O)(O2)2(L)] catalysts (L = Mepz, a; 3,5-dimethylpyrazole, dmpz, b; and H2O, c) indicated that a Sharpless-type outer-sphere mechanism is more probable than a Thiel-type one. The highest barrier of the catalytic profile was the oxo-transfer step, in which the nucleophilic attack of sulphide onto the peroxide ligand occurred with formation of dioxoperoxo species. In order to yield the sulfoxide and the starting catalyst, the oxidation of the resulting dioxoperoxo species with H2O2 was found to be the most favourable pathway. Subsequently, the sulfoxide to sulfone oxidation was performed through a similar mechanism involving the [Mo(O)(O2)2(L)] catalyst. The comparable energies found for the successive two oxo-transfer steps were in agreement with the experimental formation of sulfone in both the reaction with an excess of the oxidant and the stoichiometric reaction in the absence of the oxidant. In the latter case, diphenylsulfone was isolated as the major product in the 1 : 1 combination of diphenylsulphide and [Mo(O)(O2)2(Mepz)2] in the ionic liquid [C4mim][PF6]. Also, the compounds [HMepz]4[Mo8O26(Mepz)2]·2H2O, 1, [Hdmpz]4[Mo8O26(dmpz)2]·2dmpz, , and [Hpz]4[Mo8O22(O2)4(pz)2]·3H2O, 3, were obtained by treating in water, stoichiometrically, dimethylsulfoxide and the corresponding [Mo(O)(O2)2(L)2] complex (L = Mepz; 3,5-dimethylpyrazole, dmpz; pyrazol, pz). The crystal structures of octanuclear compounds 1-3 were indirect proof of the formation of the theoretically proposed intermediates.

  6. 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.

  7. Antibiotic-Resistant Bacteria.

    Science.gov (United States)

    Longenecker, Nevin E.; Oppenheimer, Dan

    1982-01-01

    A study conducted by high school advanced bacteriology students appears to confirm the hypothesis that the incremental administration of antibiotics on several species of bacteria (Escherichia coli, Staphylococcus epidermis, Bacillus sublitus, Bacillus megaterium) will allow for the development of antibiotic-resistant strains. (PEB)

  8. Mycophagous soil bacteria

    NARCIS (Netherlands)

    Rudnick, M.B.

    2015-01-01

    Abstract

    Soil microorganisms evolved several strategies to compete for limited nutrients in soil. Bacteria of the genus Collimonas developed a way to exploit fungi as a source of organic nutrients. This strategy has been termed “mycophagy&r

  9. Is Your ATM Dispensing Bacteria?

    Science.gov (United States)

    ... news/fullstory_162067.html Is Your ATM Dispensing Bacteria? Study in New York City found most of ... keypads in New York City were covered in bacteria, researchers reported, with most of the microbes coming ...

  10. Exopolysaccharides from Marine Bacteria

    Institute of Scientific and Technical Information of China (English)

    CHI Zhenming; FANG Yan

    2005-01-01

    Microbial polysaccharides represent a class of important products of growing interest for many sectors of industry. In recent years, there has been a growing interest in isolating new exopolysaccharides (EPSs)-producing bacteria from marine environments, particularly from various extreme marine environments. Many new marine microbial EPSs with novel chemical compositions, properties and structures have been found to have potential applications in fields such as adhesives,textiles, pharmaceuticals and medicine for anti-cancer, food additives, oil recovery and metal removal in mining and industrial waste treatments, etc This paper gives a brief summary of the information about the EPSs produced by marine bacteria,including their chemical compositions, properties and structures, together with their potential applications in industry.

  11. Genomics of oral bacteria.

    Science.gov (United States)

    Duncan, Margaret J

    2003-01-01

    Advances in bacterial genetics came with the discovery of the genetic code, followed by the development of recombinant DNA technologies. Now the field is undergoing a new revolution because of investigators' ability to sequence and assemble complete bacterial genomes. Over 200 genome projects have been completed or are in progress, and the oral microbiology research community has benefited through projects for oral bacteria and their non-oral-pathogen relatives. This review describes features of several oral bacterial genomes, and emphasizes the themes of species relationships, comparative genomics, and lateral gene transfer. Genomics is having a broad impact on basic research in microbial pathogenesis, and will lead to new approaches in clinical research and therapeutics. The oral microbiota is a unique community especially suited for new challenges to sequence the metagenomes of microbial consortia, and the genomes of uncultivable bacteria.

  12. 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.

  13. South-Seeking Magnetic Bacteria

    OpenAIRE

    Kirschvink, J.L.

    1980-01-01

    Magnetotactic bacteria, originally discovered by Blakemore (1975), are by far the most convincing and abundant example of magnetically sensitive organisms in existence. Their magnetite crystals passively align the bacteria with the earth's magnetic field like a 3-dimensional compass (Frankel et al. 1979). These microaerophilic bacteria normally live in the soupy, oxygen-poor mud/water transition zone in many freshwater and marine environments. If the mud is disturbed so that the bacteria are ...

  14. Cable Bacteria in Freshwater Sediments

    OpenAIRE

    Risgaard-Petersen, Nils; Kristiansen, Michael; Frederiksen, Rasmus B.; Dittmer, Anders Lindequist; Bjerg, Jesper Tataru; Trojan, Daniela; Schreiber, Lars; Damgaard, Lars Riis; Schramm, Andreas; Nielsen, Lars Peter

    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 fre...

  15. 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

  16. Bacteria counting method based on polyaniline/bacteria thin film.

    Science.gov (United States)

    Zhihua, Li; Xuetao, Hu; Jiyong, Shi; Xiaobo, Zou; Xiaowei, Huang; Xucheng, Zhou; Tahir, Haroon Elrasheid; Holmes, Mel; Povey, Malcolm

    2016-07-15

    A simple and rapid bacteria counting method based on polyaniline (PANI)/bacteria thin film was proposed. Since the negative effects of immobilized bacteria on the deposition of PANI on glass carbon electrode (GCE), PANI/bacteria thin films containing decreased amount of PANI would be obtained when increasing the bacteria concentration. The prepared PANI/bacteria film was characterized with cyclic voltammetry (CV) technique to provide quantitative index for the determination of the bacteria count, and electrochemical impedance spectroscopy (EIS) was also performed to further investigate the difference in the PANI/bacteria films. Good linear relationship of the peak currents of the CVs and the log total count of bacteria (Bacillus subtilis) could be established using the equation Y=-30.413X+272.560 (R(2)=0.982) over the range of 5.3×10(4) to 5.3×10(8)CFUmL(-1), which also showed acceptable stability, reproducibility and switchable ability. The proposed method was feasible for simple and rapid counting of bacteria. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Brotes germinados y bacterias

    OpenAIRE

    García Olmedo, Francisco

    2011-01-01

    Ante la confusión y el revuelo asociados al último incidente causado por una cepa de la bacteria Escherichia coli (E. coli) en Alemania, tal vez no esté de más esta carta para recordar y actualizar escritos míos anteriores aparecidos en Revista de Libros sobre los riesgos alimentarios en general y sobre los peligros de dicho microorganismo en particular. 1 . Aunque es cierto que la proporción de cepas peligrosas de E. coli es quizás inferior a la de delincuentes entre los humanos, exi...

  18. Phylogeny and distribution of nitrate-storing Beggiatoa spp. in coastal marine sediments

    DEFF Research Database (Denmark)

    Mussmann, M.; Schulz, HN; Strotmann, B.

    2003-01-01

    Filamentous sulphide-oxidizing Beggiatoa spp. often occur in large numbers in the coastal seabed without forming visible mats on the sediment surface. We studied the diversity, population structure and the nitrate-storing capability of such bacteria in the Danish Limfjorden and the German Wadden...... Sea. Their distribution was compared to the vertical gradients of O-2 , NO3 (-) and H-2 S as measured by microsensors. The main Beggiatoa spp. populations occurred in a 0.5-3 cm thick intermediate zone, below the depth of oxygen and nitrate penetration but above the zone of free sulphide...... by coupling sulphide oxidation with the reduction of nitrate to dinitrogen and/or ammonia. Calculations of the diffusive nitrate flux and the potential sulphide oxidation by Beggiatoa spp. show that the bacteria may play a critical role for the sulphur cycling and the nitrogen balance in these coastal...

  19. Beneficial bacteria inhibit cachexia.

    Science.gov (United States)

    Varian, Bernard J; Goureshetti, Sravya; Poutahidis, Theofilos; Lakritz, Jessica R; Levkovich, Tatiana; Kwok, Caitlin; Teliousis, Konstantinos; Ibrahim, Yassin M; Mirabal, Sheyla; Erdman, Susan E

    2016-03-15

    Muscle wasting, known as cachexia, is a debilitating condition associated with chronic inflammation such as during cancer. Beneficial microbes have been shown to optimize systemic inflammatory tone during good health; however, interactions between microbes and host immunity in the context of cachexia are incompletely understood. Here we use mouse models to test roles for bacteria in muscle wasting syndromes. We find that feeding of a human commensal microbe, Lactobacillus reuteri, to mice is sufficient to lower systemic indices of inflammation and inhibit cachexia. Further, the microbial muscle-building phenomenon extends to normal aging as wild type animals exhibited increased growth hormone levels and up-regulation of transcription factor Forkhead Box N1 [FoxN1] associated with thymus gland retention and longevity. Interestingly, mice with a defective FoxN1 gene (athymic nude) fail to inhibit sarcopenia after L. reuteri therapy, indicating a FoxN1-mediated mechanism. In conclusion, symbiotic bacteria may serve to stimulate FoxN1 and thymic functions that regulate inflammation, offering possible alternatives for cachexia prevention and novel insights into roles for microbiota in mammalian ontogeny and phylogeny.

  20. Chemical communication in bacteria

    Science.gov (United States)

    Suravajhala, Srinivasa Sandeep; Saini, Deepak; Nott, Prabhu

    Luminescence in Vibrio fischeri is a model for quorum-sensing-gene-regulation in bacteria. We study luminescence response of V. fischeri to both internal and external cues at the single cell and population level. Experiments with ES114, a wild-type strain, and ainS mutant show that luminescence induction in cultures is not always proportional to cell-density and there is always a basal level of luminescence. At any given concentration of the exogenously added signals, C6-HSL and C8-HSL, luminescence per cell reaches a maximum during the exponential phase and decreases thereafter. We hypothesize that (1) C6-HSL production and LuxR activity are not proportional to cell-density, and (2) there is a shift in equilibrium from C6-HSL to C8-HSL during the later stages of growth of the culture. RT-PCR analysis of luxI and luxR shows that the expression of these genes is maximum corresponding to the highest level of luminescence. The shift in equilibrium is shown by studying competitive binding of C6-HSL and C8-HSL to LuxR. We argue that luminescence is a unicellular behaviour, and an intensive property like per cell luminescence is more important than gross luminescence of the population in understanding response of bacteria to chemical signalling. Funding from the Department of Science and Technology, India is acknowledged.

  1. Replication Restart in Bacteria.

    Science.gov (United States)

    Michel, Bénédicte; Sandler, Steven J

    2017-07-01

    In bacteria, replication forks assembled at a replication origin travel to the terminus, often a few megabases away. They may encounter obstacles that trigger replisome disassembly, rendering replication restart from abandoned forks crucial for cell viability. During the past 25 years, the genes that encode replication restart proteins have been identified and genetically characterized. In parallel, the enzymes were purified and analyzed in vitro, where they can catalyze replication initiation in a sequence-independent manner from fork-like DNA structures. This work also revealed a close link between replication and homologous recombination, as replication restart from recombination intermediates is an essential step of DNA double-strand break repair in bacteria and, conversely, arrested replication forks can be acted upon by recombination proteins and converted into various recombination substrates. In this review, we summarize this intense period of research that led to the characterization of the ubiquitous replication restart protein PriA and its partners, to the definition of several replication restart pathways in vivo, and to the description of tight links between replication and homologous recombination, responsible for the importance of replication restart in the maintenance of genome stability. Copyright © 2017 American Society for Microbiology.

  2. 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...

  3. 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...... 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...... 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...

  4. Bacteria transport under unsaturated conditions

    OpenAIRE

    Gargiulo, Grazia

    2007-01-01

    The aim of this work was to study the bacteria transport behaviour in different conditions using an unsaturated porous media. A column based system able to keep the unsaturated conditions was designed and developed to perform the experiments. Two bacteria strains Deinococcus radiodurans and Rhodococcus rhodochrous strongly different in hydrophobicity were employed. During the experiments the bacteria concentration in the outflow was continuously on-line measured and after the experiment the c...

  5. Bacteriophages of methanotrophic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Tyutikow, F.M. (All-Union Research Inst. for Genetics and Selection of Industrial Microorganisms, Moscow, USSR); Bespalova, I.A.; Rebentish, B.A.; Aleksandrushkina, N.N.; Krivisky, A.S.

    1980-10-01

    Bacteriophages of methanotrophic bacteria have been found in 16 out of 88 studied samples (underground waters, pond water, soil, gas and oil installation waters, fermentor cultural fluids, bacterial paste, and rumen of cattle) taken in different geographic zones of the Soviet Union. Altogether, 23 phage strains were isolated. By fine structure, the phages were divided into two types (with very short or long noncontractile tails); by host range and serological properties, they fell into three types. All phages had guanine- and cytosine-rich double-stranded deoxyribonucleic acid consisting of common nitrogen bases. By all of the above-mentioned properties, all phages within each of the groups were completely identical to one another, but differed from phages of other groups.

  6. 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.

  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. Swimming bacteria in liquid crystal

    Science.gov (United States)

    Sokolov, Andrey; Zhou, Shuang; Aranson, Igor; Lavrentovich, Oleg

    2014-03-01

    Dynamics of swimming bacteria can be very complex due to the interaction between the bacteria and the fluid, especially when the suspending fluid is non-Newtonian. Placement of swimming bacteria in lyotropic liquid crystal produces a new class of active materials by combining features of two seemingly incompatible constituents: self-propelled live bacteria and ordered liquid crystals. Here we present fundamentally new phenomena caused by the coupling between direction of bacterial swimming, bacteria-triggered flows and director orientations. Locomotion of bacteria may locally reduce the degree of order in liquid crystal or even trigger nematic-isotropic phase transition. Microscopic flows generated by bacterial flagella disturb director orientation. Emerged birefringence patterns allow direct optical observation and quantitative characterization of flagella dynamics. At high concentration of bacteria we observed the emergence of self-organized periodic texture caused by bacteria swimming. Our work sheds new light on self-organization in hybrid bio-mechanical systems and can lead to valuable biomedical applications. Was supported by the US DOE, Office of Basic Energy Sciences, Division of Materials Science and Engineering, under the Contract No. DE AC02-06CH11357.

  9. Ecophysiology of the anammox bacteria

    NARCIS (Netherlands)

    Kartal, Mustafa Boran

    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 cost-effecti

  10. 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

  11. 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....

  12. Dynamics of anoxygenic photosynthesis in an experimental green sulphur bacteria biofilm

    DEFF Research Database (Denmark)

    Pringault, Olivier; Epping, E.H.G.; Guyoneaud, Remy

    1999-01-01

    procedure to solve the non-stationary general diffusion equation. A close agreement was found between the areal rates of anoxygenic photosynthesis during the cycling procedure and the steady state before the cycling experiment. For the different layers of the biofilm, the maximum activity was observed after...... 10–12 min of light exposure. After this maximum, sulphide oxidation decreased concomitantly with sulphide concentration, indicating sulphide limitation of anoxygenic photosynthesis. This lag time limits the application of the standard dark–light shift method with a brief light exposure of a few...... seconds and, therefore, the numerical procedure described in this study enables the depth distribution of anoxygenic photosynthesis rates in microbial mats to be determined more accurately....

  13. Commensal ocular bacteria degrade mucins.

    Science.gov (United States)

    Berry, M; Harris, A; Lumb, R; Powell, K

    2002-12-01

    Antimicrobial activity in tears prevents infection while maintaining a commensal bacterial population. The relation between mucin and commensal bacteria was assessed to determine whether commensals possess mucinolytic activity, how degradation depends on mucin integrity, and whether mucins affect bacterial replication. Bacteria were sampled from healthy eyes and contact lenses from asymptomatic wearers. Intracellular mucins were extracted and purified from cadaver conjunctivas, and surface mucins from extended wear contact lenses. After exposure to bacteria, changes in mucin hydrodynamic volume (proteolytic cleavage) and subunit charge (oligosaccharide degradation) were assayed by size exclusion and ion exchange chromatography. The effect of mucin on bacterial replication was followed for up to 24 hours from the end of incubation with purified ocular mucins. Ocular bacteria decreased the hydrodynamic volume of intracellular and contact lens adherent mucins, irrespective of glycosylation density. A decrease in mucin sialylation was observed after exposure to commensal bacteria. Subunit charge distributions were generally shifted to lesser negative charge, consistent with loss of charged epitopes. Subunits with high negative charge, observed after digesting lightly adhering contact lens mucins with bacteria, suggest preferential cleavage sites in the mucin molecule. The presence of purified ocular mucin in the medium inhibited bacterial growth. Bacteria in the healthy ocular surface possess mucinolytic activity on both intact and surface processed mucins, targeted to discrete sites in the mucin molecule. Inhibition of bacterial growth by ocular mucins can be seen as part of the mucosal control of microbiota.

  14. Sampling bacteria with a laser

    Science.gov (United States)

    Schwarzwälder, Kordula; Rutschmann, Peter

    2014-05-01

    Water quality is a topic of high interest and it's getting more and more important due to climate change and the implementation of European Water Framework Directive (WFD). One point of interest here is the inflow of bacteria into a river caused by combined sewer overflows which lead untreated wastewater including bacteria directly into a river. These bacteria remain in the river for a certain time, they settle down and can be remobilised again. In our study we want to investigate these processes of sedimentation and resuspension and use the results for the development of a software module coupled with the software Flow3D. Thereby we should be able to simulate and therefore predict the water quality influenced by combined sewer overflows. Hence we need to get information about the bacteria transport and fate. We need to know about the size of the bacteria or of the bacteria clumps and the size of the particles the bacteria are attached to. The agglomerates lead to different characteristics and velocities of settlement. The timespan during this bacteria can be detected in the bulk phase depends on many factors like the intensity of UV light, turbidity of the water, the temperature of the water, if there are grazers and a lot more. The size, density and composition of the agglomerates is just a part of all these influencing factors, but it is extremely difficult to differ between the other effects if we have no information about the simple sedimentation in default of these basic information. However we have a big problem getting the data. The chaining between bacteria or bacteria and particles is not too strong, so filtering the water to get a sieving curve may destroy these connections. We did some experiments similar to PIV (particle image velocimetry) measurements and evaluated the pictures with a macro written for the software ImageJ. Doing so we were able to get the concentration of bacteria in the water and collect information about the size of the bacteria. We

  15. Motility of Electric Cable Bacteria

    OpenAIRE

    Bjerg, Jesper Tataru; Damgaard, Lars Riis; Holm, Simon Agner; Schramm, Andreas; Nielsen, Lars Peter

    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 0.5 ± 0.3 μm s−1 (mean ± standard deviation) and time between reversals of 155 ± 108 s. They frequently moved forward in loops, and formation of twisted loops revealed ...

  16. 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

  17. 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 Mega

  18. Sewage-pollution indicator bacteria

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaiah, N.; Rodrigues, V.; Alwares, E.; Rodrigues, C.; Baksh, R.; Jayan, S.; Mohandass, C.

    Spatial distribution and annual cycle of sewage pollution indicator (total coliforms and total fecal coliforms) and human pathogenic bacteria (Escherichia coli and Streptococcus faecalis) in water and sediment samples in the Mandovi and Zuari...

  19. 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....

  20. LACTIC ACID BACTERIA: PROBIOTIC APPLICATIONS

    OpenAIRE

    NEENA GARG

    2015-01-01

    Lactic acid bacteria (LAB) is a heterotrophic Gram-positive bacteria which under goes lactic acid fermentations and leads to production of lactic acid as an end product. LAB includes Lactobacillus, Leuconostoc, Pediococcus, Lactococcus and Streptococcus which are grouped together in the family lactobacillaceae. LAB shows numerous antimicrobial activities due to production of antibacterial and antifungal compounds such as organic acids, bacteriocins, diacetyl, hydrogen peroxide and reutrin. LA...

  1. 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....

  2. Geobiology of Marine Magnetotactic Bacteria

    Science.gov (United States)

    2006-06-01

    Coast. Shelf Sci., 45:769-788. [38] Overmann, J. and H. van Gemerden. 2000. Microbial interactions involving sulfur bacteria: implications for the...1998) Organic acids in the rhizosphere : a critical review. Plant and Soil 205: 25-44. J0rgensen BB, Kuenen JG, Cohen Y (1979) Microbial ...my advisor Katrina Edwards for taking a chance on someone who initially knew nothing about magnetotactic bacteria, microbial ecology, or microbiology

  3. A comparative effect of 3 disinfectants on heterotrophic bacteria, iron bacteria and sulfate-reducing bacteria

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The disinfection effect of chlorine dioxide, chlorine and their mixture on heterotrophic bacteria, iron bacteria and sulfate-reducing bacteria in circulating cooling water was studied. The results of the test indicated that high purity chlorine dioxide was the most effective biocide in the 3 disinfectants, and with a dosage of 0.5mg/L, chlorine dioxide could obtain perfect effect. High purity chloride dioxide could have the excellent effect with the pH value of 6 to 10, and could keep it within 72 h. Chlorine and their mixture couldn't reach the effect of chlorine dioxide.

  4. Bioreporter bacteria for landmine detection

    Energy Technology Data Exchange (ETDEWEB)

    Burlage, R.S. [Oak Ridge National Lab., TN (United States); Youngblood, T. [Frisby Technologies, Aiken, SC (United States); Lamothe, D. [American Technologies, Inc., Huntsville, AL (United States). Ordnance/Explosives Environmental Services Div.

    1998-04-01

    Landmines (and other UXO) gradually leak explosive chemicals into the soil at significant concentrations. Bacteria, which have adapted to scavenge low concentrations of nutrients, can detect these explosive chemicals. Uptake of these chemicals results in the triggering of specific bacterial genes. The authors have created genetically recombinant bioreporter bacteria that detect small concentrations of energetic chemicals. These bacteria are genetically engineered to produce a bioluminescent signal when they contact specific explosives. A gene for a brightly fluorescent compound can be substituted for increased sensitivity. By finding the fluorescent bacteria, you find the landmine. Detection might be accomplished using stand-off illumination of the minefield and GPS technology, which would result in greatly reduced risk to the deminers. Bioreporter technology has been proven at the laboratory scale, and will be tested under field conditions in the near future. They have created a bacterial strain that detects sub-micromolar concentrations of o- and p-nitrotoluene. Related bacterial strains were produced using standard laboratory protocols, and bioreporters of dinitrotoluene and trinitrotoluene were produced, screening for activity with the explosive compounds. Response time is dependent on the growth rate of the bacteria. Although frill signal production may require several hours, the bacteria can be applied over vast areas and scanned quickly, producing an equivalent detection speed that is very fast. This technology may be applicable to other needs, such as locating buried explosives at military and ordnance/explosive manufacturing facilities.

  5. Filtrating forms of soil bacteria

    Science.gov (United States)

    Van'kova, A. A.; Ivanov, P. I.; Emtsev, V. T.

    2013-03-01

    Filtrating (ultramicroscopic) forms (FF) of bacteria were studied in a soddy-podzolic soil and the root zone of alfalfa plants as part of populations of the most widespread physiological groups of soil bacteria. FF were obtained by filtering soil solutions through membrane filters with a pore diameter of 0.22 μm. It was established that the greater part of the bacteria in the soil and in the root zone of the plants has an ultramicroscopic size: the average diameter of the cells is 0.3 μm, and their length is 0.6 μm, which is significantly less than the cell size of banal bacteria. The number of FF varies within a wide range depending on the physicochemical conditions of the habitat. The FF number's dynamics in the soil is of a seasonal nature; i.e., the number of bacteria found increases in the summer and fall and decreases in the winter-spring period. In the rhizosphere of the alfalfa, over the vegetation period, the number of FF and their fraction in the total mass of the bacteria increase. A reverse tendency is observed in the rhizoplane. The morphological particularities (identified by an electron microscopy) and the nature of the FF indicate their physiological activity.

  6. Cable Bacteria in Freshwater Sediments.

    Science.gov (United States)

    Risgaard-Petersen, Nils; Kristiansen, Michael; Frederiksen, Rasmus B; Dittmer, Anders Lindequist; Bjerg, Jesper Tataru; Trojan, Daniela; Schreiber, Lars; Damgaard, Lars Riis; Schramm, Andreas; Nielsen, Lars Peter

    2015-09-01

    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 and electric fields indicated electron transfer between vertically separated anodic and cathodic half-reactions. Fluorescence in situ hybridization revealed the presence of Desulfobulbaceae filaments. In addition, in situ measurements of oxygen, pH, and electric potential distributions in the waterlogged banks of Giber Å demonstrated the presence of distant electric redox coupling in naturally occurring freshwater sediment. At the same site, filamentous Desulfobulbaceae with cable bacterium morphology were found to be present. Their 16S rRNA gene sequence placed them as a distinct sister group to the known 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 origin of the cable phenotype within Desulfobulbaceae with subsequent diversification into a freshwater and a marine lineage.

  7. Natural occurrence of microbial sulphur oxidation by long-range electron transport in the seafloor

    NARCIS (Netherlands)

    Malkin, S.Y.; Rao, A.M.F.; Seitaj, D.; Vasquez-Cardenas, D.; Zetsche, E.-M.; Hidalgo-Martinez, S.; Boschker, H.T.S.; Meysman, F.J.R.

    2014-01-01

    Recently, a novel mode of sulphur oxidation was described in marine sediments, in which sulphide oxidation in deeper anoxic layers was electrically coupled to oxygen reduction at the sediment surface. Subsequent experimental evidence identified that long filamentous bacteria belonging to the family

  8. Isolation and Identification of Concrete Environment Bacteria

    Science.gov (United States)

    Irwan, J. M.; Anneza, L. H.; Othman, N.; Husnul, T.; Alshalif, A. F.

    2016-07-01

    This paper presents the isolation and molecular method for bacteria identification through PCR and DNA sequencing. Identification of the bacteria species is required in order to fully utilize the bacterium capability for precipitation of calcium carbonate in concrete. This process is to enable the addition of suitable catalyst according to the bacterium enzymatic pathway that is known through the bacteria species used. The objective of this study is to isolate, enriched and identify the bacteria species. The bacteria in this study was isolated from fresh urine and acid mine drainage water, Kota Tinggi, Johor. Enrichment of the isolated bacteria was conducted to ensure the bacteria survivability in concrete. The identification of bacteria species was done through polymerase chain reaction (PCR) and rRDNA sequencing. The isolation and enrichment of the bacteria was done successfully. Whereas, the results for bacteria identification showed that the isolated bacteria strains are Bacillus sp and Enterococus faecalis.

  9. [Genetic resources of nodule bacteria].

    Science.gov (United States)

    Rumiantseva, M L

    2009-09-01

    Nodule bacteria (rhizobia) form highly specific symbiosis with leguminous plants. The efficiency of accumulation of biological nitrogen depends on molecular-genetic interaction between the host plant and rhizobia. Genetic characteristics of microsymbiotic strains are crucial in developing highly productive and stress-resistant symbiotic pairs: rhizobium strain-host plant cultivar (species). The present review considers the issue of studying genetic resources of nodule bacteria to identify genes and their blocks, responsible for the ability of rhizobia to form highly effective symbiosis in various agroecological conditions. The main approaches to investigation of intraspecific and interspecific genetic and genomic diversity of nodule bacteria are considered, from MLEE analysis to the recent methods of genomic DNA analysis using biochips. The data are presented showing that gene centers of host plants are centers of genetic diversification of nodule bacteria, because the intraspecific polymorphism of genetic markers of the core and the accessory rhizobial genomes is extremely high in them. Genotypic features of trapped and nodule subpopulations of alfalfa nodule bacteria are discussed. A survey of literature showed that the genomes of natural strains in alfalfa gene centers exhibit significant differences in genes involved in control of metabolism, replication, recombination, and the formation of defense response (hsd genes). Natural populations of rhizobia are regarded as a huge gene pool serving as a source of evolutionary innovations.

  10. 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....

  11. 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.

  12. IDENTIFICATION OF BACTERIA IN LATEX PAINTS

    Directory of Open Access Journals (Sweden)

    Rojas, J.

    2008-01-01

    Full Text Available The bacteria are prokaryote organisms with a high capacity to colonize many types of habits. This research was developed with the object to identify extremophiles bacteria presents in latex paint. The bacteria were cultivated in culture mediums TSA, Blood Agar, Mc Conkey and finally the biochemical proof API-NF® for bacteria's isolation and identification, respectively. Characterization showed bacterial profile of Pasteurella sp. Hypothesis that could be found extremophiles bacteria in latex paint were demonstrated.

  13. Adaptation, Bacteria and Maxwell's Demons

    Science.gov (United States)

    Galajda, Peter; Keymer, Juan E.; Austin, Robert H.

    2007-03-01

    We propose a method to study the adaptation of bacterial populations with an asymmetric wall of Maxwell Demon openings. A Maxwell Demon opening is a funnel which is easier to enter than to leave. The interaction of swimming cells with such a Maxwell Demon Wall results in a population density separation, in apparent (but not real) violation of the Second Law of Thermodynamics, as we will show. Bacteria can be exposed to spatial challenges in order to move to e. g. higher food levels. The question we address in these experiments is: do the bacteria adapt and overcome the Maxwell Demon Wall?

  14. Bioenergetics of Monoterpenoid Essential Oil Biosynthesis in Non-Photosynthetic Glandular Trichomes.

    Science.gov (United States)

    Johnson, Sean R; Lange, Iris; Srividya, Narayanan; Lange, Bernd Markus

    2017-08-24

    The commercially important essential oils of peppermint (Mentha x piperita L.) and its relatives in the mint family (Lamiaceae) are accumulated in specialized anatomical structures called glandular trichomes (GTs). A genome-scale stoichiometric model of secretory phase metabolism in peppermint GTs was constructed based on current biochemical and physiological knowledge. Fluxes through the network were predicted based on metabolomic and transcriptomic data. Using simulated reaction deletions, this model predicted that two processes, the regeneration of ATP and ferredoxin (in its reduced form), exert substantial control over flux toward monoterpenes. Follow-up biochemical assays with isolated GTs indicated that oxidative phosphorylation and ethanolic fermentation were active, and that cooperation to provide ATP depended on the concentration of the carbon source. We also report that GTs with high flux toward monoterpenes express, at very high levels, genes coding for a unique pair of ferredoxin and ferredoxin-NADP+ reductase isoforms. This study provides the first evidence how bioenergetic processes determine flux through monoterpene biosynthesis in GTs. {copyright, serif} 2017 American Society of Plant Biologists. All rights reserved.

  15. Biochemistry, proteomics, and phosphoproteomics of plant mitochondria from non-photosynthetic cells

    DEFF Research Database (Denmark)

    Havelund, Jesper; Thelen, Jay J.; Møller, Ian Max

    2013-01-01

    Mitochondria fulfill some basic roles in all plant cells. They supply the cell with energy in the form of ATP and reducing equivalents (NAD(P)H) and they provide the cell with intermediates for a range of biosynthetic pathways. In addition to this, mitochondria contribute to a number of specialized...... functions depending on the tissue and cell type, as well as environmental conditions. We will here review the biochemistry and proteomics of mitochondria from non-green cells and organs, which differ from those of photosynthetic organs in a number of respects. We will briefly cover purification...... of mitochondria and general biochemical properties such as oxidative phosphorylation. We will then mention a few adaptive properties in response to water stress, seed maturation and germination and the ability to function under hypoxic conditions. The discussion will mainly focus on Arabidopsis cell cultures...

  16. Biochemistry, proteomics and phosphoproteomics of plant mitochondria from non-photosynthetic cells

    Directory of Open Access Journals (Sweden)

    Jesper Foged Havelund

    2013-03-01

    Full Text Available Mitochondria fulfill some basic roles in all plant cells. They supply the cell with energy in the form of ATP and reducing equivalents (NAD(PH and they provide the cell with intermediates for a range of biosynthetic pathways. In addition to this, mitochondria contribute to a number of specialized functions depending on the tissue and cell type, as well as environmental conditions. We will here review the biochemistry and proteomics of mitochondria from non-green cells and organs, which differ from those of photosynthetic organs in a number of respects. We will briefly cover purification of mitochondria and general biochemical properties such as oxidative phosphorylation. We will then mention a few adaptive properties in response to water stress, seed maturation and germination and the ability to function under hypoxic conditions. The discussion will mainly focus on Arabidopsis cell cultures, etiolated germinating rice seedlings and potato tubers as model plants. It will cover the general proteome as well as the posttranslational modification protein phosphorylation. To date 64 phosphorylated mitochondrial proteins with a total of 103 phosphorylation sites have been identified.

  17. Biochemistry, proteomics, and phosphoproteomics of plant mitochondria from non-photosynthetic cells

    DEFF Research Database (Denmark)

    Havelund, Jesper; Thelen, Jay J.; Møller, Ian Max

    2013-01-01

    functions depending on the tissue and cell type, as well as environmental conditions. We will here review the biochemistry and proteomics of mitochondria from non-green cells and organs, which differ from those of photosynthetic organs in a number of respects. We will briefly cover purification...

  18. Pre-biotic stage of life origin under non-photosynthetic conditions

    Science.gov (United States)

    Bartsev, S. I.; Mezhevikin, V. V.

    2005-01-01

    Spontaneous assembling of a simplest bacterial cell even if all necessary molecules are present in a solution seems to be extremely rare event and from the scientific standpoint has to be considered as impossible. Therefore, a predecessor of a living cell has to be very simple for providing its self-assembling and at the same time it should be able of progressive increase in complexity. Now phase-separated particles, first of all micelles, are put forward as possible predecessors of living cell. According to the offered working concept only phase-separated particles possessing autocatalytic properties can be considered as predecessors of living cells. The first stage of evolution of these phase-separated autocatalytic systems is the appearance of pre-biotic metabolism providing synthesis of amphiphiles for formation of capsules of these systems. This synthesis is maintained by the energy of a base reaction being a component of a planet-chemical cycle. Catalytic system providing functioning of pre-biotic metabolism is based on multivariate oligomeric autocatalyst, which reproduces itself from monomers, penetrating the particles from the outside. Since the autocatalyst realizes random polymerization then a collection of other oligomers possessing different catalytic functions is produced. In the paper the functioning of multivariate oligomeric autocatalyst in flow reactor is analyzed. c2005 Published by Elsevier Ltd on behalf of COSPAR.

  19. Differential allocation to photosynthetic and non-photosynthetic nitrogen fractions among native and invasive species.

    Science.gov (United States)

    Funk, Jennifer L; Glenwinkel, Lori A; Sack, Lawren

    2013-01-01

    Invasive species are expected to cluster on the "high-return" end of the leaf economic spectrum, displaying leaf traits consistent with higher carbon assimilation relative to native species. Intra-leaf nitrogen (N) allocation should support these physiological differences; however, N biochemistry has not been examined in more than a few invasive species. We measured 34 leaf traits including seven leaf N pools for five native and five invasive species from Hawaii under low irradiance to mimic the forest understory environment. We found several trait differences between native and invasive species. In particular, invasive species showed preferential N allocation to metabolism (amino acids) rather than photosynthetic light reactions (membrane-bound protein) by comparison with native species. The soluble protein concentration did not vary between groups. Under these low irradiance conditions, native species had higher light-saturated photosynthetic rates, possibly as a consequence of a greater investment in membrane-bound protein. Invasive species may succeed by employing a wide range of N allocation mechanisms, including higher amino acid production for fast growth under high irradiance or storage of N in leaves as soluble protein or amino acids.

  20. Differential allocation to photosynthetic and non-photosynthetic nitrogen fractions among native and invasive species.

    Directory of Open Access Journals (Sweden)

    Jennifer L Funk

    Full Text Available Invasive species are expected to cluster on the "high-return" end of the leaf economic spectrum, displaying leaf traits consistent with higher carbon assimilation relative to native species. Intra-leaf nitrogen (N allocation should support these physiological differences; however, N biochemistry has not been examined in more than a few invasive species. We measured 34 leaf traits including seven leaf N pools for five native and five invasive species from Hawaii under low irradiance to mimic the forest understory environment. We found several trait differences between native and invasive species. In particular, invasive species showed preferential N allocation to metabolism (amino acids rather than photosynthetic light reactions (membrane-bound protein by comparison with native species. The soluble protein concentration did not vary between groups. Under these low irradiance conditions, native species had higher light-saturated photosynthetic rates, possibly as a consequence of a greater investment in membrane-bound protein. Invasive species may succeed by employing a wide range of N allocation mechanisms, including higher amino acid production for fast growth under high irradiance or storage of N in leaves as soluble protein or amino acids.

  1. Manipulating Genetic Material in Bacteria

    Science.gov (United States)

    1998-01-01

    Lisa Crawford, a graduate research assistant from the University of Toledo, works with Laurel Karr of Marshall Space Flight Center (MSFC) in the molecular biology laboratory. They are donducting genetic manipulation of bacteria and yeast for the production of large amount of desired protein. Photo credit: NASA/Marshall Space Flight Center (MSFC)

  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. 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...

  4. Functional genomics of intracellular bacteria.

    Science.gov (United States)

    de Barsy, Marie; Greub, Gilbert

    2013-07-01

    During the genomic era, a large amount of whole-genome sequences accumulated, which identified many hypothetical proteins of unknown function. Rapidly, functional genomics, which is the research domain that assign a function to a given gene product, has thus been developed. Functional genomics of intracellular pathogenic bacteria exhibit specific peculiarities due to the fastidious growth of most of these intracellular micro-organisms, due to the close interaction with the host cell, due to the risk of contamination of experiments with host cell proteins and, for some strict intracellular bacteria such as Chlamydia, due to the absence of simple genetic system to manipulate the bacterial genome. To identify virulence factors of intracellular pathogenic bacteria, functional genomics often rely on bioinformatic analyses compared with model organisms such as Escherichia coli and Bacillus subtilis. The use of heterologous expression is another common approach. Given the intracellular lifestyle and the many effectors that are used by the intracellular bacteria to corrupt host cell functions, functional genomics is also often targeting the identification of new effectors such as those of the T4SS of Brucella and Legionella.

  5. Hydrocarbon degradation by antarctic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Cavanagh, J.A.E.; Nichols, P.D.; McMeekin, T.A.; Franzmann, P.D. [Univ. of Tasmania (Australia)] [and others

    1996-12-31

    Bacterial cultures obtained from sediment samples collected during a trial oil spill experiment conducted at Airport beach, Eastern Antarctica were selectively enriched for n-alkane-degrading and phenanthrenedegrading bacteria. Samples were collected from a control site and sites treated with different hydrocarbon mixtures - Special Antarctic blend (SAB), BP-Visco and orange roughy oils. One set of replicate sites was also treated with water from Organic Lake which had previously been shown to contain hydrocarbon-degrading bacteria. No viable bacteria were obtained from samples collected from sites treated with orange roughy oil. Extensive degradation of n-alkanes by enrichment cultures obtained from sites treated with SAB and BP-Visco occurred at both 25{degrees}C and 10{degrees}C. Extensive degradation of phenanthrene also occurred in enrichment cultures from these sites grown at 25{degrees}C. Concurrent increases of polar lipid in these cultures were also observed. The presence of 1,4-naphthaquinone and 1-naphthol during the growth of the cultures on phenanthrene is unusual and warrants further investigation of the mechanism of phenanthrene-degradation by these Antarctic bacteria.

  6. 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.

  7. Engineering robust lactic acid bacteria

    NARCIS (Netherlands)

    Bron, P.A.; Bokhorst-van de Veen, van H.; Wels, M.; Kleerebezem, M.

    2011-01-01

    For centuries, lactic acid bacteria (LAB) have been industrially exploited as starter cultures in the fermentation of foods and feeds for their spoilage-preventing and flavor-enhancing characteristics. More recently, the health-promoting effects of LAB on the consumer have been widely acknowledged,

  8. Photoreceptor proteins from purple bacteria

    NARCIS (Netherlands)

    Hendriks, J.; van der Horst, M.A.; Chua, T.K.; Ávila Pérez, M.; van Wilderen, L.J.; Alexandre, M.T.A.; Groot, M.-L.; Kennis, J.T.M.; Hellingwerf, K.J.; Hunter, C.N.; Daldal, F.; Thurnauer, M.C.; Beatty, J.T.

    2009-01-01

    Purple bacteria contain representatives of four of the six main families of photoreceptor proteins: phytochromes, BLUF domain containing proteins, xanthopsins (i.e., photoactive yellow proteins), and phototropins (containing one or more light, oxygen, or voltage (LOV) domains). Most of them have a

  9. 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

  10. SYNTHETIC BIOLOGY IN STREPTOMYCES BACTERIA

    NARCIS (Netherlands)

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

    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 t

  11. 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.

  12. Hybridization of cloned Rhodopseudomonas capsulata photosynthesis genes with DNA from other photosynthetic bacteria.

    OpenAIRE

    Beatty, J T; Cohen, S N

    1983-01-01

    The homology of Rhodopseudomonas capsulata DNA segments carrying photosynthesis genes with sequences present in total DNA from certain other photosynthetic and non-photosynthetic bacterial species was determined by hybridization. R. capsulata DNA fragments that carry loci for production of peptide components of the photosynthetic reaction center and light-harvesting I antenna complex were found to hybridize to DNA from some photosynthetic species. However, fragments that carry carotenoid or b...

  13. Pesticide Exposures May Alter Mouth Bacteria

    Science.gov (United States)

    ... fullstory_162249.html Pesticide Exposures May Alter Mouth Bacteria Study of Washington farm workers finds alterations persist ... News) -- Pesticide exposure may change the makeup of bacteria in the mouths of farm workers, a new ...

  14. Smokeless Tobacco May Contain Potentially Harmful Bacteria

    Science.gov (United States)

    ... 160769.html Smokeless Tobacco May Contain Potentially Harmful Bacteria Infections, diarrhea and vomiting are possible consequences, FDA ... products can harbor several species of potentially harmful bacteria, researchers warn. Two types in particular -- Bacillus licheniformis ...

  15. Certain Bacteria May Affect Preterm Birth Risk

    Science.gov (United States)

    ... https://medlineplus.gov/news/fullstory_163401.html Certain Bacteria May Affect Preterm Birth Risk Bad 'bugs' tied ... Feb. 3, 2017 (HealthDay News) -- Certain types of bacteria in a pregnant woman's cervix and vagina can ...

  16. Aggregation Patterns in Stressed Bacteria

    CERN Document Server

    Tsimring, L S; Aranson, I S; Ben-Jacob, E; Cohen, I; Shochet, O; Tsimring, Lev; Levine, Herbert; Aranson, Igor; Ben-Jacob, Eshel; Cohen, Inon; Shochet, Ofer

    1995-01-01

    We study the formation of spot patterns seen in a variety of bacterial species when the bacteria are subjected to oxidative stress due to hazardous byproducts of respiration. Our approach consists of coupling the cell density field to a chemoattractant concentration as well as to nutrient and waste fields. The latter serves as a triggering field for emission of chemoattractant. Important elements in the proposed model include the propagation of a front of motile bacteria radially outward form an initial site, a Turing instability of the uniformly dense state and a reduction of motility for cells sufficiently far behind the front. The wide variety of patterns seen in the experiments is explained as being due the variation of the details of the initiation of the chemoattractant emission as well as the transition to a non-motile phase.

  17. 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).

  18. LACTIC ACID BACTERIA: PROBIOTIC APPLICATIONS

    Directory of Open Access Journals (Sweden)

    NEENA GARG

    2015-10-01

    Full Text Available Lactic acid bacteria (LAB is a heterotrophic Gram-positive bacteria which under goes lactic acid fermentations and leads to production of lactic acid as an end product. LAB includes Lactobacillus, Leuconostoc, Pediococcus, Lactococcus and Streptococcus which are grouped together in the family lactobacillaceae. LAB shows numerous antimicrobial activities due to production of antibacterial and antifungal compounds such as organic acids, bacteriocins, diacetyl, hydrogen peroxide and reutrin. LAB are used as starter culture, consortium members and bioprotective agents in food industry that improve food quality, safety and shelf life. A variety of probiotic LAB species are available including Lactobacillus acidophilus, L. bulgaricus, L. lactis, L. plantarum, L. rhamnosus, L. reuteri, L. fermentum, Bifidobacterium longum, B. breve, B. bifidum, B. esselnsis, B. lactis, B. infantis that are currently recommended for development of functional food products with health-promoting capacities.

  19. Dissipative Shocks behind Bacteria Gliding

    CERN Document Server

    Virga, Epifanio G

    2014-01-01

    Gliding is a means of locomotion on rigid substrates utilized by a number of bacteria includingmyxobacteria and cyanobacteria. One of the hypotheses advanced to explain this motility mechanism hinges on the role played by the slime filaments continuously extruded from gliding bacteria. This paper solves in full a non-linear mechanical theory that treats as dissipative shocks both the point where the extruded slime filament comes in contact with the substrate, called the filament's foot, and the pore on the bacterium outer surface from where the filament is ejected. We prove that kinematic compatibility for shock propagation requires that the bacterium uniform gliding velocity (relative to the substrate) and the slime ejecting velocity (relative to the bacterium) must be equal, a coincidence that seems to have already been observed.

  20. 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.

  1. Compartmentalization of bacteria in microcapsules.

    Science.gov (United States)

    van Wijk, Judith; Heunis, Tiaan; Harmzen, Elrika; Dicks, Leon M T; Meuldijk, Jan; Klumperman, Bert

    2014-12-18

    Lactobacillus plantarum strain 423 was encapsulated in hollow poly(organosiloxane) microcapsules by templating water-in-oil Pickering emulsion droplets via the interfacial reaction of alkylchlorosilanes. The bacteria were suspended in growth medium or buffer to protect the cells against pH changes during the interfacial reactions with alkylchlorosilanes. The results of this work open up novel avenues for the encapsulation of microbial cells.

  2. Endocytosis of Viruses and Bacteria

    Science.gov (United States)

    Cossart, Pascale; Helenius, Ari

    2014-01-01

    Of the many pathogens that infect humans and animals, a large number use cells of the host organism as protected sites for replication. To reach the relevant intracellular compartments, they take advantage of the endocytosis machinery and exploit the network of endocytic organelles for penetration into the cytosol or as sites of replication. In this review, we discuss the endocytic entry processes used by viruses and bacteria and compare the strategies used by these dissimilar classes of pathogens. PMID:25085912

  3. Characterization of Mediterranean Magnetotactic Bacteria

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Magnetotactic bacteria are a diverse group of motile prokaryotes that are ubiquitous in aquatic habitats and cosmopolitan in distribution. In this study, we collected magnetotactic bacteria from the Mediterranean Sea. A remarkable diversity of morphotypes was observed, including muiticellular types that seemed to differ from those previously found in North and South America. Another interesting organism was one with magnetosomes arranged in a six-stranded bundle which occupied one third of the cell width. The magnetosome bundle was evident even under optic microscopy. These cells were connected together and swam as a linear entire unit. Magnetosomes did not always align up to form a straight linear chain. A chain composed of rectangle magnetosomes bent at a position with an oval crystal. High resolution transmission electron microscopy analysis of the crystal at the pivotal position suggested uncompleted formation of the crystal. This is the first report of Mediterranean magnetotactic bacteria, which should be useful for studies of biogeochemical cycling and geohistory of the Mediterranean Sea.

  4. 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 common that

  5. 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…

  6. 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 distribut

  7. 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…

  8. 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 micro

  9. 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 bact

  10. 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

  11. Corrosion of alloy 800H and the effect of surface-applied CeO2 in a sulphidizing/oxidizing/carburizing environment at 700°C

    NARCIS (Netherlands)

    Stroosnijder, M.F.; Guttmann, V.; Fransen, T.; Wit, de J.H.W.

    1990-01-01

    The corrosion behavior of a wrought austenitic Fe-20Cr-32Ni steel, Alloy 800H, was studied in a simulated coal-gasification atmosphere at 700°C for exposure times up to 2500 hr. The influence of preoxidation and CeO2-surface application followed by preoxidation on the corrosion resistance of this ma

  12. [Bacteria ecology in planting-culturing system].

    Science.gov (United States)

    Huang, Fenglian; Xia, Beicheng; Dai, Xin; Chen, Guizhu

    2004-06-01

    Planting-culturing system in inter-tidal zone is a new type eco-culturing model. The survey on bacteria biomass and water quality in the designed planting-culturing system in inter-tidal zone showed that the mangrove planted in the system improved water quality and made water quality to II-III type, better than the IV and V type in the control pond. Designed ponds made heterotrophic bacteria, vibrio, phosphorus bacteria and enzyme-producing bacteria populations 1-2 order lower than the control pond without mongrove planting. Correlation analyses with CORREL software showed that the biomass of these bacteria was positively related with the nitrogen and phosphorus contents in water of the system, and the correlation coefficient for heterogeneous bacteria and vibrio was up to 0.9205. Heterotrophic bacteria and vibrio could be used as the water-quality monitoring organisms.

  13. Ciliates as engineers of phototrophic biofilms

    NARCIS (Netherlands)

    Weerman, Ellen J.; van der Geest, Harm G.; van der Meulen, Myra D.; Manders, Erik M. M.; van de Koppel, Johan; Herman, Peter M. J.; Admiraal, Wim

    2011-01-01

    1. Phototrophic biofilms consist of a matrix of phototrophs, non-photosynthetic bacteria and extracellular polymeric substances (EPS) which is spatially structured. Despite widespread exploitation of algae and bacteria within phototrophic biofilms, for example by protozoans, the 'engineering' effect

  14. 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.

  15. DMTB: the magnetotactic bacteria database

    Science.gov (United States)

    Pan, Y.; Lin, W.

    2012-12-01

    Magnetotactic bacteria (MTB) are of interest in biogeomagnetism, rock magnetism, microbiology, biomineralization, and advanced magnetic materials because of their ability to synthesize highly ordered intracellular nano-sized magnetic minerals, magnetite or greigite. Great strides for MTB studies have been made in the past few decades. More than 600 articles concerning MTB have been published. These rapidly growing data are stimulating cross disciplinary studies in such field as biogeomagnetism. We have compiled the first online database for MTB, i.e., Database of Magnestotactic Bacteria (DMTB, http://database.biomnsl.com). It contains useful information of 16S rRNA gene sequences, oligonucleotides, and magnetic properties of MTB, and corresponding ecological metadata of sampling sites. The 16S rRNA gene sequences are collected from the GenBank database, while all other data are collected from the scientific literature. Rock magnetic properties for both uncultivated and cultivated MTB species are also included. In the DMTB database, data are accessible through four main interfaces: Site Sort, Phylo Sort, Oligonucleotides, and Magnetic Properties. References in each entry serve as links to specific pages within public databases. The online comprehensive DMTB will provide a very useful data resource for researchers from various disciplines, e.g., microbiology, rock magnetism and paleomagnetism, biogeomagnetism, magnetic material sciences and others.

  16. Mitochondria are not captive bacteria.

    Science.gov (United States)

    Harish, Ajith; Kurland, Charles G

    2017-12-07

    Lynn Sagan's conjecture (1967) that three of the fundamental organelles observed in eukaryote cells, specifically mitochondria, plastids and flagella were once free-living primitive (prokaryotic) cells was accepted after considerable opposition. Even though the idea was swiftly refuted for the specific case of origins of flagella in eukaryotes, the symbiosis model in general was accepted for decades as a realistic hypothesis to describe the endosymbiotic origins of eukaryotes. However, a systematic analysis of the origins of the mitochondrial proteome based on empirical genome evolution models now indicates that 97% of modern mitochondrial protein domains as well their homologues in bacteria and archaea were present in the universal common ancestor (UCA) of the modern tree of life (ToL). These protein domains are universal modular building blocks of modern genes and genomes, each of which is identified by a unique tertiary structure and a specific biochemical function as well as a characteristic sequence profile. Further, phylogeny reconstructed from genome-scale evolution models reveals that Eukaryotes and Akaryotes (archaea and bacteria) descend independently from UCA. That is to say, Eukaryotes and Akaryotes are both primordial lineages that evolved in parallel. Finally, there is no indication of massive inter-lineage exchange of coding sequences during the descent of the two lineages. Accordingly, we suggest that the evolution of the mitochondrial proteome was autogenic (endogenic) and not endosymbiotic (exogenic). Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. The mycorrhiza helper bacteria revisited.

    Science.gov (United States)

    Frey-Klett, P; Garbaye, J; Tarkka, M

    2007-01-01

    In natural conditions, mycorrhizal fungi are surrounded by complex microbial communities, which modulate the mycorrhizal symbiosis. Here, the focus is on the so-called mycorrhiza helper bacteria (MHB). This concept is revisited, and the distinction is made between the helper bacteria, which assist mycorrhiza formation, and those that interact positively with the functioning of the symbiosis. After considering some examples of MHB from the literature, the ecological and evolutionary implications of the relationships of MHB with mycorrhizal fungi are discussed. The question of the specificity of the MHB effect is addressed, and an assessment is made of progress in understanding the mechanisms of the MHB effect, which has been made possible through the development of genomics. Finally, clear evidence is presented suggesting that some MHB promote the functioning of the mycorrhizal symbiosis. This is illustrated for three critical functions of practical significance: nutrient mobilization from soil minerals, fixation of atmospheric nitrogen, and protection of plants against root pathogens. The review concludes with discussion of future research priorities regarding the potentially very fruitful concept of MHB.

  18. 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...

  19. Serological studies on chloridazon-degrading bacteria.

    Science.gov (United States)

    Layh, G; Böhm, R; Eberspächer, J; Lingens, F

    1983-01-01

    Agglutination tests and immunofluorescence tests with antisera against four strains of chloridazon-degrading bacteria revealed the serological uniformity of a group of 22 chloridazon-degrading bacterial strains. No serological relationship could be found between chloridazon-degrading bacteria and representatives of other Gram-negative bacteria. This was demonstrated by agglutination tests, including testing of the antiserum against Acinetobacter calcoaceticus, and by immunofluorescence tests, including testing of the sera against Pseudomonas and Acinetobacter strains. The tests were performed with 31 representatives of different Gram-negative bacteria, and with 22 strains of chloridazon-degrading bacteria as antigens. Differences in the extent of agglutination reactions and antibody titres among chloridazon-degrading bacterial strains together with cross-adsorption xperiments, suggest a rough classification of chloridazon-degrading bacteria into two subgroups. On the basis of immunofluorescence data, a linkage-map was worked out to represent serological relationships in the group of chloridazon-degrading strains.

  20. Coryneform bacteria associated with canine otitis externa

    DEFF Research Database (Denmark)

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

    2010-01-01

    of coryneform bacteria was 16% among 55 cases of canine otitis externa examined at the Danish hospital during 2007. In contrast, detectable levels of coryneform bacteria were not demonstrated in samples from the acustic meatus of 35 dogs with apparently healthy ears, attending the hospital during the same year......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...

  1. Endophytic bacteria in Coffea arabica L.

    Science.gov (United States)

    Vega, Fernando E; Pava-Ripoll, Monica; Posada, Francisco; Buyer, Jeffrey S

    2005-01-01

    Eighty-seven culturable endophytic bacterial isolates in 19 genera were obtained from coffee plants collected in Colombia (n = 67), Hawaii (n = 17), and Mexico (n = 3). Both Gram positive and Gram negative bacteria were isolated, with a greater percentage (68%) being Gram negative. Tissues yielding bacterial endophytes included adult plant leaves, various parts of the berry (e.g., crown, pulp, peduncle and seed), and leaves, stems, and roots of seedlings. Some of the bacteria also occurred as epiphytes. The highest number of bacteria among the berry tissues sampled was isolated from the seed, and includes Bacillus , Burkholderia , Clavibacter , Curtobacterium , Escherichia , Micrococcus , Pantoea , Pseudomonas , Serratia , and Stenotrophomonas . This is the first survey of the endophytic bacteria diversity in various coffee tissues, and the first study reporting endophytic bacteria in coffee seeds. The possible role for these bacteria in the biology of the coffee plant remains unknown.

  2. 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.

  3. Survival of soil bacteria during prolonged desiccation.

    Science.gov (United States)

    Chen, M.; Alexander, M.

    1973-01-01

    A determination was made of the kinds and numbers of bacteria surviving when two soils were maintained in the laboratory under dry conditions for more than half a year. Certain non-spore-forming bacteria were found to survive in the dry condition for long periods. A higher percentage of drought-tolerant than drought-sensitive bacteria was able to grow at low water activities. When they were grown in media with high salt concentrations, bacteria generally became more tolerant of prolonged drought and they persisted longer. The percent of cells in a bacterial population that remained viable when exposed to drought stress varied with the stage of growth.

  4. 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...

  5. Coryneform bacteria associated with canine otitis externa.

    Science.gov (United States)

    Aalbæk, Bent; Bemis, David A; Schjærff, Mette; Kania, Stephen A; Frank, Linda A; Guardabassi, Luca

    2010-10-26

    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 bacteria, mainly Staphylococcus pseudintermedius alone (n=5) or in combination with Malassezia pachydermatis (n=5). Some coryneform isolates displayed resistance to fusidic acid or enrofloxacin, two antimicrobial agents commonly used for the treatment of otitis externa in dogs. The frequency of isolation of coryneform bacteria was 16% among 55 cases of canine otitis externa examined at the Danish hospital during 2007. In contrast, detectable levels of coryneform bacteria were not demonstrated in samples from the acustic meatus of 35 dogs with apparently healthy ears, attending the hospital during the same year. On basis of the current knowledge, these coryneform bacteria should be regarded as potential secondary pathogens able to proliferate in the environment of an inflamed ear canal.

  6. Single Bacteria as Turing Machines

    Science.gov (United States)

    Bos, Julia; Zang, Qiucen; Vyawahare, Saurabh; Austin, Robert

    2014-03-01

    In Allan Turing's famous 1950 paper on Computing Machinery and Intelligence, he started with the provocative statement: ``I propose to consider the question, `Can machines think?' This should begin with definitions of the meaning of the terms `machine' and `think'.'' In our own work on exploring the way that organisms respond to stress and evolve, it seems at times as if they come to remarkably fast solutions to problems, indicating some sort of very clever computational machinery. I'll discuss how it would appear that bacteria can indeed create a form of a Turing Machine, the first example of a computer, and how they might use this algorithm to do rapid evolution to solve a genomics problem.

  7. 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.

  8. 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

  9. Mitochondria: a target for bacteria.

    Science.gov (United States)

    Lobet, Elodie; Letesson, Jean-Jacques; Arnould, Thierry

    2015-04-01

    Eukaryotic cells developed strategies to detect and eradicate infections. The innate immune system, which is the first line of defence against invading pathogens, relies on the recognition of molecular patterns conserved among pathogens. Pathogen associated molecular pattern binding to pattern recognition receptor triggers the activation of several signalling pathways leading to the establishment of a pro-inflammatory state required to control the infection. In addition, pathogens evolved to subvert those responses (with passive and active strategies) allowing their entry and persistence in the host cells and tissues. Indeed, several bacteria actively manipulate immune system or interfere with the cell fate for their own benefit. One can imagine that bacterial effectors can potentially manipulate every single organelle in the cell. However, the multiple functions fulfilled by mitochondria especially their involvement in the regulation of innate immune response, make mitochondria a target of choice for bacterial pathogens as they are not only a key component of the central metabolism through ATP production and synthesis of various biomolecules but they also take part to cell signalling through ROS production and control of calcium homeostasis as well as the control of cell survival/programmed cell death. Furthermore, considering that mitochondria derived from an ancestral bacterial endosymbiosis, it is not surprising that a special connection does exist between this organelle and bacteria. In this review, we will discuss different mitochondrial functions that are affected during bacterial infection as well as different strategies developed by bacterial pathogens to subvert functions related to calcium homeostasis, maintenance of redox status and mitochondrial morphology.

  10. Progress in Research of Bacteria Fertilizer Strengthening Resistance of Plants

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Bacteria fertilizer is used most widely among all kinds of microbial fertilizers. We summarize the research headway of bacteria fertilizer. It mainly focuses on bacteria fertilizer improving the stress resistance of plant. Then we can offer basis to research and exploit bacteria fertilizer. These bacteria include azotobacter, photosynthetic bacteria, Bacillus mucilaginosus siliceous, phosphorus bacteria, plant growth-promoting rhizobacteria(PGPR), effective microorganism(EM).

  11. 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 belo

  12. Lactic Acid Bacteria in the Gut

    NARCIS (Netherlands)

    Stolaki, M.; Vos, de W.M.; Kleerebezem, M.; Zoetendal, E.G.

    2012-01-01

    From all bacterial groups, the lactic acid bacteria (LAB) are probably the group of bacteria that is most associated with human lifestyle. The term LAB mainly refers to the ability of these organisms to convert sugars to lactic acid. The LAB comprise non-sporing, aerotolerant, coccus or rod-shaped,

  13. 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...

  14. 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....

  15. 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...

  16. Symbiosis: Gut Bacteria Manipulate Host Behaviour.

    Science.gov (United States)

    Yuval, Boaz

    2017-08-07

    Bacteria resident in the gut of Drosophila modify the fly's innate chemosensory responses to nutritional stimuli. In effect, the gut microbiome compels the host to forage on food patches that favour particular assemblages of bacteria. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Why do bacteria engage in homologous recombination?

    NARCIS (Netherlands)

    Vos, M.

    2009-01-01

    Microbiologists have long recognized that the uptake and incorporation of homologous DNA from outside the cell is a common feature of bacteria, with important implications for their evolution. However, the exact reasons why bacteria engage in homologous recombination remain elusive. This Opinion

  18. Lactic Acid Bacteria in the Gut

    NARCIS (Netherlands)

    Stolaki, M.; Vos, de W.M.; Kleerebezem, M.; Zoetendal, E.G.

    2012-01-01

    From all bacterial groups, the lactic acid bacteria (LAB) are probably the group of bacteria that is most associated with human lifestyle. The term LAB mainly refers to the ability of these organisms to convert sugars to lactic acid. The LAB comprise non-sporing, aerotolerant, coccus or rod-shaped,

  19. Energy transduction in lactic acid bacteria

    NARCIS (Netherlands)

    Poolman, Bert

    In the discovery of some general principles of energy transduction, lactic acid bacteria have played an important role. In this review, the energy transducing processes of lactic acid bacteria are discussed with the emphasis on the major developments of the past 5 years. This work not only includes

  20. Method of dispersing a hydrocarbon using bacteria

    Science.gov (United States)

    Tyndall, Richard L.

    1996-01-01

    New protozoan derived microbial consortia and method for their isolation are provided. Consortia and bacteria isolated therefrom are useful for treating wastes such as trichloroethylene and trinitrotoluene. Consortia, bacteria isolated therefrom, and dispersants isolated therefrom are useful for dispersing hydrocarbons such as oil, creosote, wax, and grease.

  1. 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%).

  2. 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...

  3. Why do bacteria engage in homologous recombination?

    NARCIS (Netherlands)

    Vos, M.

    2009-01-01

    Microbiologists have long recognized that the uptake and incorporation of homologous DNA from outside the cell is a common feature of bacteria, with important implications for their evolution. However, the exact reasons why bacteria engage in homologous recombination remain elusive. This Opinion art

  4. Bacteria dispersal by hitchhiking on zooplankton

    DEFF Research Database (Denmark)

    Grossart, Hans-Peter; Dziallas, Claudia; Leunert, Franziska;

    2010-01-01

    and nonpathogenic bacteria has shown that direct association with zooplankton has significant influences on the bacteria's physiology and ecology. We used stratified migration columns to study vertical dispersal of hitchhiking bacteria through migrating zooplankton across a density gradient that was otherwise...... impenetrable for bacteria in both upward and downward directions (conveyor-belt hypothesis). The strength of our experiments is to permit quantitative estimation of transport and release of associated bacteria: vertical migration of Daphnia magna yielded an average dispersal rate of 1.3 x 10(5) x cells x...... Daphnia(-1) x migration cycle(-1) for the lake bacterium Brevundimonas sp. Bidirectional vertical dispersal by migrating D. magna was also shown for two other bacterial species, albeit at lower rates. The prediction that diurnally migrating zooplankton acquire different attached bacterial communities from...

  5. Hydrocarbon Degrading Bacteria: Isolation and Identification

    Directory of Open Access Journals (Sweden)

    Lies Indah Sutiknowati

    2007-11-01

    Full Text Available There is little information how to identify hydrocarbon degrading bacteria for bioremediation of marine oil spills. We have used gravel which contaminated oil mousse from Beach Simulator Tank, in Marine Biotechnology Institute, Kamaishi, Japan, and grown on enrichment culture. Biostimulation with nutrients (N and P was done to analyze biodegradation of hydrocarbon compounds: Naphthalene, Phenanthrene, Trichlorodibenzofuran and Benzo[a]pyrene. Community of bacteria from enrichment culture was determined by DGGE. Isolating and screening the bacteria on inorganic medium contain hydrocarbon compounds and determination of bacteria by DAPI (number of cells and CFU. DNA was extracted from colonies of bacteria and sequence determination of the 16S rDNA was amplified by primers U515f and U1492r. Twenty nine strains had been sequence and have similarity about 90-99% to their closest taxa by homology Blast search and few of them have suspected as new species.

  6. 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.

  7. Chryseobacterium indologenes, novel mannanase-producing bacteria

    Directory of Open Access Journals (Sweden)

    Surachai Rattanasuk

    2009-10-01

    Full Text Available Mannanase is a mannan degrading enzyme which is produced by microorganisms, including bacteria. This enzyme can be used in many industrial processes as well as for improving the quality of animal feeds. The aim of the present study was toscreen and characterize the mannanase-producing bacteria. Two genera of bacteria were isolated from Thai soil samples,fermented coconut, and fertilizer. Screening was carried out on agar plates containing mannan stained with iodine solution.The bacteria were identified by partial 16S rRNA gene sequence, biochemical test and morphology, respectively. The mannanase activity was determined by zymogram and DNS method. Two strains of bacteria with mannanase activity were identified as Bacillus and Chryseobacterium. This is the first report of mannanase-producing Chryseobacterium.

  8. 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...

  9. Antibiotic resistance in probiotic bacteria

    Directory of Open Access Journals (Sweden)

    Miguel eGueimonde

    2013-07-01

    Full Text Available Probiotics are live microorganisms which when administered in adequate amounts confer a health benefit on the host. The main probiotic bacteria are strains belonging to the genera Lactobacillus and Bifidobacterium, although other representatives, such as Bacillus or Escherichia coli strains, have also been used. Lactobacillus and Bifidobacterium are two common inhabitants of the human intestinal microbiota. Also, some species are used in food fermentation processes as starters, or as adjunct cultures in the food industry. With some exceptions, antibiotic resistance in these beneficial microbes does not constitute a safety concern in itself, when mutations or intrinsic resistance mechanisms are responsible for the resistance phenotype. In fact, some probiotic strains with intrinsic antibiotic resistance could be useful for restoring the gut microbiota after antibiotic treatment. However, specific antibiotic resistance determinants carried on mobile genetic elements, such as tetracycline resistance genes, are often detected in the typical probiotic genera, and constitute a reservoir of resistance for potential food or gut pathogens, thus representing a serious safety issue.

  10. Comparative cytotoxicity of periodontal bacteria

    Energy Technology Data Exchange (ETDEWEB)

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

    1988-11-01

    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.

  11. 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.

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

    Science.gov (United States)

    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 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.

  13. 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.

  14. 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.

  15. Light scattering by marine heterotrophic bacteria

    Science.gov (United States)

    Ulloa, Osvaldo; Sathyendranath, Shubha; Platt, Trevor; Quinones, Renato A.

    1992-01-01

    Mie theory is applied to estimate scattering by polydispersions of marine heterotrophic bacteria, and a simple expression is derived for the bacterial scattering coefficient. The error incurred in deriving bacterial optical properties by use of the van de Hulst approximations is computed. The scattering properties of natural bacterial assemblages in three marine environments, Georges Bank, Northeast Channel, and Sargasso Sea, are assessed by applying Mie theory to field data on bacterial size and abundance. Results are used to examine the potential contribution of bacteria to the scattering properties of seawater. The utility of using pigment data to predict the magnitude of scattering by bacteria is discussed.

  16. Do symbiotic bacteria subvert host immunity?

    Science.gov (United States)

    Hooper, Lora V

    2009-05-01

    The mammalian intestine is home to dense and complex indigenous bacterial communities. Most of these bacteria establish beneficial symbiotic relationships with their hosts, making important contributions to host metabolism and digestive efficiency. The vast numbers of intestinal bacteria and their proximity to host tissues raise the question of how symbiotic host-bacterial relationships are established without eliciting potentially harmful immune responses. In light of the varied ways in which pathogenic bacteria manipulate host immunity, this Opinion article explores the role of immune suppression, subversion and evasion in the establishment of symbiotic host-bacterial associations.

  17. 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....

  18. Anaerobic bacteria, the colon and colitis.

    Science.gov (United States)

    Roediger, W E

    1980-02-01

    Anaerobic bacteria constitute more than 90% of the bacteria in the colon. An anaerobic environment is needed to maintain their growth and the production of short-chain fatty acids by these bacteria from carbohydrates. Short-chain fatty acids are rapidly absorbed and essential for metabolic as well as functional welfare of the colonic mucosa. The importance of these acids in water absorption and in the patogenesis of colitis is discussed in relation to the concept of "energy deficiency diseases" of the colonic mucosa.

  19. 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....

  20. 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, carn

  1. 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.

  2. Bioluminescent hydrocarbonclastic bacteria of the Niger Delta

    African Journals Online (AJOL)

    Administrator

    2007-02-19

    Feb 19, 2007 ... Bioluminescence is the chemical emission of light by organisms (Lang and Lange, ... (TNT) – contaminated soils by two different erated comp- .... Effect of phosphate levels on growth of bioluminescent bacteria. Phosphate ...

  3. ISOLATION AND CHARACTERIZATION OF BACTERIA FROM THE ...

    African Journals Online (AJOL)

    xx

    Key words: Drosophila melanogaster, gut-bacteria, larval development, Lysinibacillus sp. P-011 .... each test, 50 1st instar larvae and three replications were used. All the tests ..... molecules are produced by the blood-sucking insect Stomoxys.

  4. 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.

  5. Discovering lactic acid bacteria by genomics

    NARCIS (Netherlands)

    Klaenhammer, T.; Altermann, E.; Arigoni, F.; Bolotin, A.; Breidt, F.; Broadbent, J.; Cano, R.; Chaillou, S.; Deutscher, J.; Gasson, M.; Guchte, van de M.; Guzzo, J.; Hartke, A.; Hawkins, T.; Hols, P.; Hutkins, R.; Kleerebezem, M.; Kok, J.; Kuipers, O.; Lubbers, M.; Maguin, E.; McKay, L.; Mills, D.; Nauta, A.; Overbeek, R.; Pel, H.; Pridmore, D.; Saier, M.; Sinderen, van D.; Sorokin, A.; Steele, J.; O'Sullivan, D.; Vos, de W.; Weimer, B.; Zagorec, M.; Siezen, R.

    2002-01-01

    This review summarizes a collection of lactic acid bacteria that are now undergoing genomic sequencing and analysis. Summaries are presented on twenty different species, with each overview discussing the organisms fundamental and practical significance, nvironmental habitat, and its role in

  6. Discovering lactic acid bacteria by genomics

    NARCIS (Netherlands)

    Klaenhammer, T; Altermann, E; Arigoni, F; Bolotin, A; Breidt, F; Broadbent, J; Cano, R; Chaillou, S; Deutscher, J; Gasson, M; van de Guchte, M; Guzzo, J; Hartke, A; Hawkins, T; Hols, P; Hutkins, R; Kleerebezem, M; Kok, J; Kuipers, O; Maguin, E; McKay, L; Mills, D; Nauta, A; Overbeek, R; Pel, H; Pridmore, D; Saier, M; van Sinderen, D; Sorokin, A; Steele, J; O'Sullivan, D; de Vos, W; Weimer, B; Zagorec, M; Siezen, R

    This review summarizes a collection of lactic acid bacteria that are now undergoing genomic sequencing and analysis. Summaries are presented on twenty different species, with each overview discussing the organisms fundamental and practical significance, environmental habitat, and its role in

  7. 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...

  8. 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...... and particularly higher organisms, covering a variety of functions ranging from pathogenic to symbiotic interactions. The detailed knowledge of these bacterial communication systems has opened completely new perspectives for controlling undesired microbial activities....

  9. Protection of probiotic bacteria in synbiotic matrices

    Science.gov (United States)

    Probiotics, like Lactobacillus acidophilus, Lactobacillus reuteri, Bifidobacterium breve, Bifidobacterium longum, when encapsulated with prebiotic fibers such as fructo-oligosaccharides (FOS), inulin (I) and pectic-oligosaccharides (POS), formed a synbiotic matrix system that protected the bacteria ...

  10. Distribution of phytopathogenic bacteria in infested seeds

    Science.gov (United States)

    Populations of phytopathogenic bacteria representing five host-pathogen combinations were assessed to determine if there was a mathematical relationship common across seedborne bacterial diseases. Bacterial populations were estimated from naturally-infested seeds of cowpea (Vigna unguiculata), peppe...

  11. Preparation of genomic DNA from bacteria.

    Science.gov (United States)

    Andreou, Lefkothea-Vasiliki

    2013-01-01

    The purpose of this protocol is the isolation of bulk cellular DNA from bacteria (alternatively see Preparation of genomic DNA from Saccharomyces cerevisiae or Isolation of Genomic DNA from Mammalian Cells protocols). Copyright © 2013 Elsevier Inc. All rights reserved.

  12. 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;

  13. 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...

  14. Quorum sensing in Gram-negative bacteria

    Institute of Scientific and Technical Information of China (English)

    WU Hong; SONG Zhijun; Niels HФIBY; Michael GIVSKOV

    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 and particularly higher organisms,covering a variety of functions ranging from pathogenic to symbiotic interactions.The detailed knowledge of these bacterial communication systems has opened completely new perspectives for controlling undesired microbial activities.

  15. T cell polarizing properties of probiotic bacteria.

    Science.gov (United States)

    Barberi, Chiara; Campana, Stefania; De Pasquale, Claudia; Rabbani Khorasgani, Mohammad; Ferlazzo, Guido; Bonaccorsi, Irene

    2015-12-01

    Different commensal bacteria employed as probiotics have been shown to be endowed with immunomodulatory properties and to actively interact with antigen presenting cells, such as dendritic cells and macrophages. In particular, different strains of probiotic bacteria may induce the secretion of a discrete cytokine profile able to induce divergent T cell polarization. Here, we briefly review current knowledge regarding the effects of different species and strains of probiotic bacteria on T cell polarization. Given that the loss of intestinal homeostasis is frequently associated with an aberrant T cell polarization profile, a comprehensive knowledge of the immunomodulatory potential of these bacteria is crucial for their employment in the management of human immune-mediated pathologies, such as allergies or inflammatory bowel diseases.

  16. Distribution of urease producing bacteria in the

    African Journals Online (AJOL)

    higher proportion of bacteria associated with the caecal wall. (63%) were facultative .... Of even more importance is the role that the domestic rabbit can and ... Until more is known about digestion of plant foods in the monogastric herbivore ...

  17. Lactic Acid Bacteria in Health and Disease

    African Journals Online (AJOL)

    reports demonstrating the health promoting effects of ... therapy. In 1908, élie Metchinkoff, proposed that the acid-producing organisms (lactic acid bacteria) ... Phage resistance aids in .... In a study conducted [29] in children aged 3 it was found.

  18. Ecology: Electrical Cable Bacteria Save Marine Life.

    Science.gov (United States)

    Nielsen, Lars Peter

    2016-01-11

    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.

  19. The antibiotics relo in bacteria resistance

    OpenAIRE

    Santana, Vinicius Canato; CESUMAR

    2007-01-01

    The paper explains how antibiotics help us to combat bacteriosis, and also presents a brief historical report about the emergence of the antibiotic era with the discovery of penicillin. It introduces the problem of bacteria resistance, and brings the concept of antibiotics and its that produce these substance, and brings the concept of antibiotics and its main function. It questions about the self-defense of the organisms that produce these substances. relates the bacteria structures attacked...

  20. [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.

  1. How do bacteria tune translation efficiency?

    OpenAIRE

    Li, Gene-Wei

    2015-01-01

    Bacterial proteins are translated with precisely determined rates to meet cellular demand. In contrast, efforts to express recombinant proteins in bacteria are often met with large unpredictability in their levels of translation. The disconnect between translation of natural and synthetic mRNA stems from the lack of understanding of the strategy used by bacteria to tune translation efficiency. The development of array-based oligonucleotide synthesis and ribosome profiling provides new approac...

  2. ORAL BACTERIA AND SYSTEMS DISEASES: A REVIEW

    OpenAIRE

    Moromi Nakata, Hilda; Profesor Principal de Microbiología, jefe de la sección de C. Dinámicas. D.A. Ciencia Básicas. Miembro permanente del Instituto de Investigaciones Estomatológicas de la Facultad de Odontología de la Universidad Nacional Mayor de San Marcos. Lima. Perú.

    2014-01-01

    In order to show a global vision of oral bacteria in systemic diseases, it is important to analyze the presence and consequences of these microorganisms in relation with: bacteremia, endocarditis, cardiovascular disease, cerebrovascular disease, bacterial pneumonia, neonatal weight, nefritis, arthritis, dermatitis and diabetes mellitus, reaching conclusions for each one of them. Con el objeto de presentar una visión general de la bacterias orales en los procesos sistémicos, se analiza la p...

  3. Quorum sensing mechanism in lactic acid bacteria

    Directory of Open Access Journals (Sweden)

    Hatice Yılmaz - Yıldıran

    2015-04-01

    and detection occurs as a consecution it is hard to understand their QS mechanism. In this review, connection between QS mechanism and some characteristics of lactic acid bacteria are evaluated such as concordance with its host, inhibition of pathogen development and colonization in gastrointestinal system, bacteriocin production, acid and bile resistance, adhesion to epithelium cells. Understanding QS mechanism of lactic acid bacteria will be useful to design metabiotics which is defined as novel probiotics.

  4. Study of Lactobacillus as Probiotic Bacteria

    OpenAIRE

    J Nowroozi; M Mirzaii; M. Norouzi

    2004-01-01

    Because of inhibitory effect, selected probiotic lactobacilli may be used as biological preservative, so, the aim of this study was to present some data on lactobacillus as probiotic bacteria. Lactic acid bacteria were isolated from sausage. Each isolate of lactobacillus species was identified by biochemical tests and comparing their sugar fermentation pattern. Antibacterial activities were done by an agar spot, well diffusion and blank disk method. Enzyme sensitivity of supernatant fluid and...

  5. 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....

  6. Study of Lactobacillus as Probiotic Bacteria

    Directory of Open Access Journals (Sweden)

    J Nowroozi

    2004-07-01

    Full Text Available Because of inhibitory effect, selected probiotic lactobacilli may be used as biological preservative, so, the aim of this study was to present some data on lactobacillus as probiotic bacteria. Lactic acid bacteria were isolated from sausage. Each isolate of lactobacillus species was identified by biochemical tests and comparing their sugar fermentation pattern. Antibacterial activities were done by an agar spot, well diffusion and blank disk method. Enzyme sensitivity of supernatant fluid and concentrated cell free culture after treatment with α-amylase, lysozyme and trypsin was determined. The isolated bacteria were Lacto. plantarum, Lacto delbruekii, Lacto. acidophilus, Lacto. brevis. The isolated bacteria had strong activity against indicator strains. The antibacterial activity was stable at 100ºC for 10 min and at 56ºC for 30 min, but activity was lost after autoclaving. The maximum production of plantaricin was obtained at 25 - 30ºC at pH 6.5. Because, lactobacilli that used to process sausage fermentation are producing antimicrobial activity with heat stability bacteriocin, so, these bacteria may be considered to be a healthy probiotic diet. Lactobacilli originally isolated from meat products are the best condidates as probiotic bacteria to improve the microbiological safety of these foods.

  7. Tyramine and phenylethylamine biosynthesis by food bacteria.

    Science.gov (United States)

    Marcobal, Angela; De las Rivas, Blanca; Landete, José María; Tabera, Laura; Muñoz, Rosario

    2012-01-01

    Tyramine poisoning is caused by the ingestion of food containing high levels of tyramine, a biogenic amine. Any foods containing free tyrosine are subject to tyramine formation if poor sanitation and low quality foods are used or if the food is subject to temperature abuse or extended storage time. Tyramine is generated by decarboxylation of the tyrosine through tyrosine decarboxylase (TDC) enzymes derived from the bacteria present in the food. Bacterial TDC have been only unequivocally identified and characterized in Gram-positive bacteria, especially in lactic acid bacteria. Pyridoxal phosphate (PLP)-dependent TDC encoding genes (tyrDC) appeared flanked by a similar genetic organization in several species of lactic acid bacteria, suggesting a common origin by a single mobile genetic element. Bacterial TDC are also able to decarboxylate phenylalanine to produce phenylethylamine (PEA), another biogenic amine. The molecular knowledge of the genes involved in tyramine production has led to the development of molecular methods for the detection of bacteria able to produce tyramine and PEA. These rapid and simple methods could be used for the analysis of the ability to form tyramine by bacteria in order to evaluate the potential risk of tyramine biosynthesis in food products.

  8. 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...

  9. Antioxidant activity of Sphaerococcus coronopifolius associated bacteria

    Directory of Open Access Journals (Sweden)

    Nádia Fino

    2014-06-01

    Full Text Available Associated bacteria living on macroalgae surfaces are an interesting source of new secondary metabolites with biological activities. The aim of this study was the isolation and identification of epiphytic bacteria from the marine algae Sphaerococcus coronopifolius and the evaluation of the antioxidant activity of the bacteria extracts. The identification of epiphytic bacteria was determined by 16S rRNA gene sequencing. Bacteria extracts were obtained with methanol and dichloromethane (1:1 extraction. Antioxidant activity was evaluated by quantification of total phenolic content (TPC, 2,2-diphenyl-1-picrylhydrazyl (DPPH radical scavenging activity and oxygen radical absorbent capacity (ORAC. The extracts with higher antioxidant activity were tested on MCF-7 and HepG-2 cell lines in oxidative stress conditions induced by H2O2 at 0.2 mM and 0.5 mM, respectively. In total were isolated 21 Sphaerococcus coronopifolius associated bacteria and identified as Vibrio sp. (28.57%, Shewanella sp. (23.81%, Pseudoalteromonas sp. (19.05%, Bacillus sp. (9.52% and Halomonas sp. (9.52%. Two (9.52% of them presented less than 90% Basic Local Alignment Search Tool (BLAST match. The epiphytic bacteria with the most antioxidant potential evaluated by ORAC and DPPH methods were Sp2, Sp12, Sp23, Sp25 and Sp27. The strain Sp4 show high antioxidant activity in all antioxidant methods (ORAC, DPPH and TPC. In oxidative stress conditions on MCF-7 cell line, the extracts of bacteria (1mg.ml-1: 24hours Sp4 (16.15%, Sp25 (17.95% and Sp27 (10.65% prevented the cell death induced by H2O2. In the HepG-2 cell line was the extracts of Sp2 (9.01%, Sp4 (11.21%, Sp12 (7.20% and Sp23 (8.81% bacteria that high prevented the oxidative stress condition induced by H2O2. In conclusion, the Sphaerococcus coronopifolius associated bacteria can be an interesting and excellent source of marine natural compounds with antioxidant activity.

  10. Phylogeny and distribution of nitrate-storing Beggiatoa spp. in coastal marine sediments

    DEFF Research Database (Denmark)

    Mussmann, M.; Schulz, HN; Strotmann, B.

    2003-01-01

    Filamentous sulphide-oxidizing Beggiatoa spp. often occur in large numbers in the coastal seabed without forming visible mats on the sediment surface. We studied the diversity, population structure and the nitrate-storing capability of such bacteria in the Danish Limfjorden and the German Wadden ....... Fluorescence in situ hybridization (FISH) of the natural Beggiatoa spp. populations showed that filament width is a conservative character of each phylogenetic species but a given filament width may represent multiple phylogenetic species in a mixed population....

  11. Results of Microbiological Research in the Polish Part of the Muskau Arch - The Largest Amd Environment in Poland - Final Report

    Directory of Open Access Journals (Sweden)

    Bożęcki Piotr

    2014-06-01

    Full Text Available This work presents the results of microbiological investigations carried out in the Polish part of the Muskau Arch. In this abandoned lignite mining area highly acidified Fe-rich waters have been formed as a result of sulphide oxidation. Microbiological tests have shown that all studied groups of microorganisms exhibit both time and spatial variability. The most common group of microorganisms are bacteria Galionella sp.

  12. 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.

  13. [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.

  14. Flagellated ectosymbiotic bacteria propel a eucaryotic cell.

    Science.gov (United States)

    Tamm, S L

    1982-09-01

    A devescovinid flagellate from termites exhibits rapid gliding movements only when in close contact with other cells or with a substrate. Locomotion is powered not by the cell's own flagella nor by its remarkable rotary axostyle, but by the flagella of thousands of rod bacteria which live on its surface. That the ectosymbiotic bacteria actually propel the protozoan was shown by the following: (a) the bacteria, which lie in specialized pockets of the host membrane, bear typical procaryotic flagella on their exposed surface; (b) gliding continues when the devescovinid's own flagella and rotary axostyle are inactivated; (c) agents which inhibit bacterial flagellar motility, but not the protozoan's motile systems, stop gliding movements; (d) isolated vesicles derived from the surface of the devescovinid rotate at speeds dependent on the number of rod bacteria still attached; (e) individual rod bacteria can move independently over the surface of compressed cells; and (f) wave propagation by the flagellar bundles of the ectosymbiotic bacteria is visualized directly by video-enhanced polarization microscopy. Proximity to solid boundaries may be required to align the flagellar bundles of adjacent bacteria in the same direction, and/or to increase their propulsive efficiency (wall effect). This motility-linked symbiosis resembles the association of locomotory spirochetes with the Australian termite flagellate Mixotricha (Cleveland, L. R., and A. V. Grimstone, 1964, Proc. R. Soc. Lond. B Biol. Sci., 159:668-686), except that in our case propulsion is provided by bacterial flagella themselves. Since bacterial flagella rotate, an additional novelty of this system is that the surface bearing the procaryotic rotary motors is turned by the eucaryotic rotary motor within.

  15. Learning from bacteria about natural information processing.

    Science.gov (United States)

    Ben-Jacob, Eshel

    2009-10-01

    Under natural growth conditions, bacteria live in complex hierarchical communities. To conduct complex cooperative behaviors, bacteria utilize sophisticated communication to the extent that their chemical language includes semantic and even pragmatic aspects. I describe how complex colony forms (patterns) emerge through the communication-based interplay between individual bacteria and the colony. Individual cells assume newly co-generated traits and abilities that are not prestored in the genetic information of the cells, that is, not all the information required for efficient responses to all environmental conditions is stored. To solve newly encountered problems, they assess the problem via collective sensing, recall stored information of past experience, and then execute distributed information processing of the 10(9)-10(12) bacteria in the colony--transforming the colony into a "super-brain." I show illuminating examples of swarming intelligence of live bacteria in which they solve optimization problems that are beyond what human beings can solve. This will lead to a discussion about the special nature of bacterial computational principles compared to Turing algorithm computational principles, in particular about the role of distributed information processing.

  16. 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.

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

    NARCIS (Netherlands)

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

    1992-01-01

    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 th

  18. 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

  19. Isolation of cellulolytic activities from Tribolium castaneum (red flour ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-12-01

    Dec 1, 2009 ... lose production by non-photosynthetic organisms inclu- ding bacteria, marine invertebrates, fungi, slime molds and amoebae has also been ... Maillet et al., 2000), arthropods (Watanabe et al., 1997;. Wei et al., 2006) and ...

  20. Fossil bacteria in Xuanlong iron ore deposits of Hebei Province

    Institute of Scientific and Technical Information of China (English)

    DAI Yongding; SONG Haiming; SHEN Jiying

    2004-01-01

    Discovered in Early Proterozoic Xuanlong iron ore deposits are six genera of fossil iron bacteria, i. e. sphere (coenobium of) rod-shaped (monomer) Naumanniella, ellipsoid elliptical Ochrobium, sphere spherical Siderocapsa and chain spherical Siderococcus, chain rod-shaped Leptothrix and Lieskeella, and six genera of fossil blue bacteria, namely sphere spherical Gloeocapsa, Synechocystis and Globobacter, chain spherical Anabaena and Nostoc, and constrictive septate tubular Nodularia. The biomineralized monomers and coenobia of the two categories of bacteria, together with hematite plates made up the bacteria pelletal, bacteria silky,bacteria fibrous and clasty bacteria pelletal textural lamina. The bacteria pelletal laminae combined with other bacteria laminae to make up oncolite, stromatolite and laminate. The precipitation of iron oxide was accelerated due to iron and blue bacteria cohabiting on microbial film or mat. The Xuanlong iron ore deposits are microbial binding ore deposits of ocean source.

  1. Studies on ultrasmall bacteria in relation to the presence of bacteria in the stratosphere

    Science.gov (United States)

    Alshammari, Fawaz; Wainwright, Milton; Alabri, Khalid; Alharbi, Sulamain A.

    2011-04-01

    Recent studies confirm that bacteria exist in the stratosphere. It is generally assumed that these bacteria are exiting from Earth, although it is possible that some are incoming from space. Most stratospheric bacterial isolates belong to the spore-forming genus Bacillus, although non-spore formers have also been isolated. Theoretically, the smaller a bacterium is, the more likely it is to be carried from Earth to the stratosphere. Ultrasmall bacteria have been frequently isolated from Earth environments, but not yet from the stratosphere. This is an anomalous situation, since we would expect such small bacteria to be over represented in the stratosphere-microflora. Here, we show that ultrasmall bacteria are present in the environment on Earth (i.e. in seawater and rainwater) and discuss the paradox of why they have not been isolated from the stratosphere.

  2. High Life Expectancy of Bacteria on Lichens.

    Science.gov (United States)

    Cernava, Tomislav; Berg, Gabriele; Grube, Martin

    2016-10-01

    Self-sustaining lichen symbioses potentially can become very old, sometimes even thousands of years in nature. In the joint structures, algal partners are sheltered between fungal structures that are externally colonized by bacterial communities. With this arrangement lichens survive long periods of drought, and lichen thalli can be revitalized even after decades of dry storage in a herbarium. To study the effects of long-term ex situ storage on viability of indigenous bacterial communities we comparatively studied herbarium-stored material of the lung lichen, Lobaria pulmonaria. We discovered that a significant fraction of the lichen-associated bacterial community survives herbarium storage of nearly 80 years, and living bacteria can still be found in even older material. As the bacteria reside in the upper surface layers of the lichen material, we argue that the extracellular polysaccharides of lichens contribute to superior life expectancy of bacteria. Deeper understanding of underlying mechanisms could provide novel possibilities for biotechnological applications.

  3. Encapsulation of probiotic bacteria in biopolymeric system.

    Science.gov (United States)

    Huq, Tanzina; Khan, Avik; Khan, Ruhul A; Riedl, Bernard; Lacroix, Monique

    2013-01-01

    Encapsulation of probiotic bacteria is generally used to enhance the viability during processing, and also for the target delivery in gastrointestinal tract. Probiotics are used with the fermented dairy products, pharmaceutical products, and health supplements. They play a great role in maintaining human health. The survival of these bacteria in the human gastrointestinal system is questionable. In order to protect the viability of the probiotic bacteria, several types of biopolymers such as alginate, chitosan, gelatin, whey protein isolate, cellulose derivatives are used for encapsulation and several methods of encapsulation such as spray drying, extrusion, emulsion have been reported. This review focuses on the method of encapsulation and the use of different biopolymeric system for encapsulation of probiotics.

  4. [Bacteriocins produced by lactic acid bacteria].

    Science.gov (United States)

    Bilková, Andrea; Sepova, Hana Kinová; Bilka, Frantisek; Balázová, Andrea

    2011-04-01

    Lactic acid bacteria comprise several genera of gram-positive bacteria that are known for the production of structurally different antimicrobial substances. Among them, bacteriocins are nowadays in the centre of scientific interest. Bacteriocins, proteinaceous antimicrobial substances, are produced ribosomally and have usually a narrow spectrum of bacterial growth inhibition. According to their structure and the target of their activity, they are divided into four classes, although there are some suggestions for a renewed classification. The most interesting and usable class are lantibiotics. They comprise the most widely commercially used and well examined bacteriocin, nisin. The non-pathogenic character of lactic acid bacteria is advantageous for using their bacteriocins in food preservation as well as in feed supplements or in veterinary medicine.

  5. Inorganic nanoparticles engineered to attack bacteria.

    Science.gov (United States)

    Miller, Kristen P; Wang, Lei; Benicewicz, Brian C; Decho, Alan W

    2015-11-01

    Antibiotics were once the golden bullet to constrain infectious bacteria. However, the rapid and continuing emergence of antibiotic resistance (AR) among infectious microbial pathogens has questioned the future utility of antibiotics. This dilemma has recently fueled the marriage of the disparate fields of nanochemistry and antibiotics. Nanoparticles and other types of nanomaterials have been extensively developed for drug delivery to eukaryotic cells. However, bacteria have very different cellular architectures than eukaryotic cells. This review addresses the chemistry of nanoparticle-based antibiotic carriers, and how their technical capabilities are now being re-engineered to attack, kill, but also non-lethally manipulate the physiologies of bacteria. This review also discusses the surface functionalization of inorganic nanoparticles with small ligand molecules, polymers, and charged moieties to achieve drug loading and controllable release.

  6. Microgravity effects on pathogenicity of bacteria

    Directory of Open Access Journals (Sweden)

    Ya-juan WANG

    2013-01-01

    Full Text Available Microgravity is one of the important environmental conditions during spaceflight. A series of studies have shown that many kinds of bacteria could be detected in space station and space shuttle. Space environment or simulated microgravity may throw a certain influence on those opportunistic pathogens and lead to some changes on their virulence, biofilm formation and drug tolerance. The mechanism of bacteria response to space environment or simulated microgravity has not been defined. However, the conserved RNA-binding protein Hfq has been identified as a likely global regulator involved in the bacteria response to this environment. In addition, microgravity effects on bacterial pathogenicity may threaten astronauts' health. The present paper will focus on microgravity-induced alterations of pathogenicity and relative mechanism in various opportunistic pathogens.

  7. 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

  8. Monitoring of environmental pollutants by bioluminescent bacteria.

    Science.gov (United States)

    Girotti, Stefano; Ferri, Elida Nora; Fumo, Maria Grazia; Maiolini, Elisabetta

    2008-02-04

    This review deals with the applications of bioluminescent bacteria to the environmental analyses, published during the years 2000-2007. The ecotoxicological assessment, by bioassays, of the environmental risks and the luminescent approaches are reported. The review includes a brief introduction to the characteristics and applications of bioassays, a description of the characteristics and applications of natural bioluminescent bacteria (BLB), and a collection of the main applications to organic and inorganic pollutants. The light-emitting genetically modified bacteria applications, as well as the bioluminescent immobilized systems and biosensors are outlined. Considerations about commercially available BLB and BLB catalogues are also reported. Most of the environmental applications, here mentioned, of luminescent organisms are on wastewater, seawater, surface and ground water, tap water, soil and sediments, air. Comparison to other bioindicators and bioassay has been also made. Various tables have been inserted, to make easier to take a rapid glance at all possible references concerning the topic of specific interest.

  9. 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.

  10. 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.

  11. Ancient bacteria show evidence of DNA repair

    DEFF Research Database (Denmark)

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

    2007-01-01

    Recent claims of cultivable ancient bacteria within sealed environments highlight our limited understanding of the mechanisms behind long-term cell survival. It remains unclear how dormancy, a favored explanation for extended cellular persistence, can cope with spontaneous genomic decay over......-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...... 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....

  12. 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.

  13. Quantification and Qualification of Bacteria Trapped in Chewed Gum

    OpenAIRE

    Wessel, Stefan W.; van der Mei, Henny C.; David Morando; Slomp, Anje M.; Betsy van de Belt-Gritter; Amarnath Maitra; 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 remove them from the oral cavity. To test this hypothesis, we developed two methods to quantify numbers of bacteria trapped in chewed gum. In the first method, known numbers of bacteria were finger-...

  14. Bacteriocins From Lactic Acid Bacteria: Interest For Food Products Biopreservation

    OpenAIRE

    Dortu, C.; Thonart, Philippe

    2009-01-01

    Bacteriocins from lactic acid bacteria: interest for food products biopreservation. Bacteriocins from lactic acid bacteria are low molecular weight antimicrobial peptides. They have inhibitory activity against the bacteria that are closed related to the producer strains and a narrow inhibitory spectrum. Nevertheless, most of them have activity against some food-born pathogenic bacteria as Listeria monocytogenes. The application of bacteriocins or bacteriocin producing lactic acid bacteria in ...

  15. Biodegradation of Complex Bacteria on Phenolic Derivatives in River Water

    Institute of Scientific and Technical Information of China (English)

    GUANG-HUA LU; CHAO WANG; ZHE SUN

    2009-01-01

    Objective To isolate, incubate, and identify 4-chlorophenol-degrading complex bacteria, determine the tolerance of these bacteria to phenolic derivatives and study their synergetic metabolism as well as the aboriginal microbes and co-metabolic degradation of mixed chlorophenols in river water. Methods Microbial community of complex bacteria was identified by plate culture observation techniques and Gram stain method. Bacterial growth inhibition test was used to determine the tolerance of complex bacteria to toxicants. Biodegradability of phenolic derivatives was determined by adding 4-chlorophenol-degrading bacteria in river water. Results The complex bacteria were identified as Mycopiana, Alcaligenes, Pseudvmonas, and Flavobacterium. The domesticated complex bacteria were more tolerant to phenolic derivatives than the aboriginal bacteria from Qinhuai River. The biodegradability of chlorophenols, dihydroxybenzenes and nitrophenols under various aquatic conditions was determined and compared. The complex bacteria exhibited a higher metabolic efficiency on chemicals than the aboriginal microbes, and the final removal rate of phenolic derivatives was increased at least by 55% when the complex bacteria were added into river water. The metabolic relationship between dominant mixed bacteria and river bacteria was studied. Conclusion The complex bacteria domesticated by 4-chlorophenol can grow and be metabolized to take other chlorophenols, dihydroxybenzenes and nitrophenols as the sole carbon and energy source. There is a synergetic metabolism of most compounds between the aboriginal microbes in river water and the domesticated complex bacteria. 4-chlorophenol-degrading bacteria can co-metabolize various chlorophenols in river water.

  16. Pervasive transcription: detecting functional RNAs in bacteria.

    Science.gov (United States)

    Lybecker, Meghan; Bilusic, Ivana; Raghavan, Rahul

    2014-01-01

    Pervasive, or genome-wide, transcription has been reported in all domains of life. In bacteria, most pervasive transcription occurs antisense to protein-coding transcripts, although recently a new class of pervasive RNAs was identified that originates from within annotated genes. Initially considered to be non-functional transcriptional noise, pervasive transcription is increasingly being recognized as important in regulating gene expression. The function of pervasive transcription is an extensively debated question in the field of transcriptomics and regulatory RNA biology. Here, we highlight the most recent contributions addressing the purpose of pervasive transcription in bacteria and discuss their implications.

  17. Bacteriophage biosensors for antibiotic-resistant bacteria.

    Science.gov (United States)

    Sorokulova, Irina; Olsen, Eric; Vodyanoy, Vitaly

    2014-03-01

    An increasing number of disease-causing bacteria are resistant to one or more anti-bacterial drugs utilized for therapy. Early and speedy detection of these pathogens is therefore very important. Traditional pathogen detection techniques, that include microbiological and biochemical assays are long and labor-intensive, while antibody or DNA-based methods require substantial sample preparation and purification. Biosensors based on bacteriophages have demonstrated remarkable potential to surmount these restrictions and to offer rapid, efficient and sensitive detection technique for antibiotic-resistant bacteria.

  18. 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.

  19. Fatty acid composition of selected prosthecate bacteria.

    Science.gov (United States)

    Carter, R N; Schmidt, J M

    1976-10-11

    The cellular fatty acid composition of 14 strains of Caulobacter speices and types, two species of Prosthecomicrobium, and two species of Asticcacaulis was determined by gas-liquid chromatography. In most of these bacteria, the major fatty acids were octadecenoic acid (C18:1), hexadecenoic acid (C16:1) and hexadecanoic acid (C16:0). Some cyclopropane and branched chain fatty acids were detected in addition to the straight chained acids. Hydroxytetradecanoic acid was an important component of P.enhydrum but significant amounts of hydroxy acids were not detected in other prosthecate bacteria examined.

  20. 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...... material is demonstrated by the bacteria‐triggered release of antibiotics to control bacterial populations and signaling molecules to modulate quorum sensing. The self‐regulating system provides the basis for the development of device‐relevant polymeric materials, which only release antibiotics...... in dependency of the titer of bacteria surrounding the medical device....

  1. 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

  2. Instabilities in the Swimming of Bacteria

    Science.gov (United States)

    Riley, Emily; Lauga, Eric

    2016-11-01

    Peritrichously flagellated bacteria, such as E. coli and B. subtillis, have flagella randomly distributed over their body. These flagella rotate to generate a pushing force that causes the cell to swim body first. For changes in direction these flagella return to their randomly distributed state where the flagella point in many different directions. The main observed state of swimming peritrichously flagellated bacteria however is one where all their flagella gathered or bundled at one end of the body. In this work we address this problem from the point of view of fluid-structure interactions and show theoretically and numerically how the conformation of flagella depends on the mechanics of the cell.

  3. DNA Barcoding on Bacteria: A Review

    Directory of Open Access Journals (Sweden)

    D. E. Lebonah

    2014-01-01

    Full Text Available Bacteria are omnipotent and they can be found everywhere. The study of bacterial pathogens has been happening from olden days to prevent epidemics, food spoilage, losses in agricultural production, and loss of lives. Modern techniques in DNA based species identification are considered. So, there is a need to acquire simple and quick identification technique. Hence, this review article covers the efficacy of DNA barcoding of bacteria. Routine DNA barcoding involves the production of PCR amplicons from particular regions to sequence them and these sequence data are used to identify or “barcode” that organism to make a distinction from other species.

  4. 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?.

  5. Polymer/bacteria composite nanofiber non-wovens by electrospinning of living bacteria protected by hydrogel microparticles.

    Science.gov (United States)

    Gensheimer, Marco; Brandis-Heep, Astrid; Agarwal, Seema; Thauer, Rudolf K; Greiner, Andreas

    2011-03-10

    Physically crosslinked PVA-hydrogel microparticles are utilized for encapsulation of E. coli and M. luteus. The bacteria survive dry storage or treatment with bacteria-hostile organic solvents significantly better than unprotected bacteria as proven by culture-test experiments. The bacteria-protecting PVA microparticles are available for standard polymer-solution-processing techniques, as exemplarily shown by co-electrospinning of living bacteria encapsulated in dry PVA-hydrogel microparticles together with PVB-, PLLA-, and PCL-form organic solvents.

  6. Bacteria in crude oil survived autoclaving and stimulated differentially by exogenous bacteria.

    Science.gov (United States)

    Gong, Xiao-Cui; Liu, Ze-Shen; Guo, Peng; Chi, Chang-Qiao; Chen, Jian; Wang, Xing-Biao; Tang, Yue-Qin; Wu, Xiao-Lei; Liu, Chun-Zhong

    2012-01-01

    Autoclaving of crude oil is often used to evaluate the hydrocarbon-degrading abilities of bacteria. This may be potentially useful for bioaugmentation and microbial enhanced oil recovery (MEOR). However, it is not entirely clear if "endogenous" bacteria (e.g., spores) in/on crude oil survive the autoclaving process, or influence subsequent evaluation of the hydrocarbon-degradation abilities of the "exogenous" bacterial strains. To test this, we inoculated autoclaved crude oil medium with six exogenous bacterial strains (three Dietzia strains, two Acinetobacter strains, and one Pseudomonas strain). The survival of the spore-forming Bacillus and Paenibacillus and the non-spore-forming mesophilic Pseudomonas, Dietzia, Alcaligenes, and Microbacterium was detected using a 16S rRNA gene clone library and terminal restriction fragment length polymorphism (T-RFLP) analysis. However, neither bacteria nor bacterial activity was detected in three controls consisting of non-inoculated autoclaved crude oil medium. These results suggest that detection of endogenous bacteria was stimulated by the six inoculated strains. In addition, inoculation with Acinetobacter spp. stimulated detection of Bacillus, while inoculation with Dietzia spp. and Pseudomonas sp. stimulated the detection of more Pseudomonas. In contrast, similar exogenous bacteria stimulated similar endogenous bacteria at the genus level. Based on these results, special emphasis should be applied to evaluate the influence of bacteria capable of surviving autoclaving on the hydrocarbon-degrading abilities of exogenous bacteria, in particular, with regard to bioaugmentation and MEOR. Bioaugmentation and MEOR technologies could then be developed to more accurately direct the growth of specific endogenous bacteria that may then improve the efficiency of treatment or recovery of crude oil.

  7. Bacteria in crude oil survived autoclaving and stimulated differentially by exogenous bacteria.

    Directory of Open Access Journals (Sweden)

    Xiao-Cui Gong

    Full Text Available Autoclaving of crude oil is often used to evaluate the hydrocarbon-degrading abilities of bacteria. This may be potentially useful for bioaugmentation and microbial enhanced oil recovery (MEOR. However, it is not entirely clear if "endogenous" bacteria (e.g., spores in/on crude oil survive the autoclaving process, or influence subsequent evaluation of the hydrocarbon-degradation abilities of the "exogenous" bacterial strains. To test this, we inoculated autoclaved crude oil medium with six exogenous bacterial strains (three Dietzia strains, two Acinetobacter strains, and one Pseudomonas strain. The survival of the spore-forming Bacillus and Paenibacillus and the non-spore-forming mesophilic Pseudomonas, Dietzia, Alcaligenes, and Microbacterium was detected using a 16S rRNA gene clone library and terminal restriction fragment length polymorphism (T-RFLP analysis. However, neither bacteria nor bacterial activity was detected in three controls consisting of non-inoculated autoclaved crude oil medium. These results suggest that detection of endogenous bacteria was stimulated by the six inoculated strains. In addition, inoculation with Acinetobacter spp. stimulated detection of Bacillus, while inoculation with Dietzia spp. and Pseudomonas sp. stimulated the detection of more Pseudomonas. In contrast, similar exogenous bacteria stimulated similar endogenous bacteria at the genus level. Based on these results, special emphasis should be applied to evaluate the influence of bacteria capable of surviving autoclaving on the hydrocarbon-degrading abilities of exogenous bacteria, in particular, with regard to bioaugmentation and MEOR. Bioaugmentation and MEOR technologies could then be developed to more accurately direct the growth of specific endogenous bacteria that may then improve the efficiency of treatment or recovery of crude oil.

  8. 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.

  9. Freeze-drying of lactic acid bacteria.

    Science.gov (United States)

    Fonseca, Fernanda; Cenard, Stéphanie; Passot, Stéphanie

    2015-01-01

    Lactic acid bacteria are of great importance for the food and biotechnology industry. They are widely used as starters for manufacturing food (e.g., yogurt, cheese, fermented meats, and vegetables) and probiotic products, as well as for green chemistry applications. Freeze-drying or lyophilization is a convenient method for preservation of bacteria. By reducing water activity to values below 0.2, it allows long-term storage and low-cost distribution at suprazero temperatures, while minimizing losses in viability and functionality. Stabilization of bacteria via freeze-drying starts with the addition of a protectant solution to the bacterial suspension. Freeze-drying includes three steps, namely, (1) freezing of the concentrated and protected cell suspension, (2) primary drying to remove ice by sublimation, and (3) secondary drying to remove unfrozen water by desorption. In this chapter we describe a method for freeze-drying of lactic acid bacteria at a pilot scale, thus allowing control of the process parameters for maximal survival and functionality recovery.

  10. Collective Sensing-Capacity of Bacteria Populations

    CERN Document Server

    Einolghozati, Arash; Fekri, Faramarz

    2012-01-01

    The design of biological networks using bacteria as the basic elements of the network is initially motivated by a phenomenon called quorum sensing. Through quorum sensing, each bacterium performs sensing the medium and communicating it to others via molecular communication. As a result, bacteria can orchestrate and act collectively and perform tasks impossible otherwise. In this paper, we consider a population of bacteria as a single node in a network. In our version of biological communication networks, such a node would communicate with one another via molecular signals. As a first step toward such networks, this paper focuses on the study of the transfer of information to the population (i.e., the node) by stimulating it with a concentration of special type of a molecules signal. These molecules trigger a chain of processes inside each bacteria that results in a final output in the form of light or fluorescence. Each stage in the process adds noise to the signal carried to the next stage. Our objective is ...

  11. The proteolytic system of lactic acid bacteria.

    Science.gov (United States)

    Mayo, B

    1993-12-01

    Lactic acid bacteria are widely used throughout the world, empirically or deliberately, in the manufacturing of several food and feed stuffs, including milk products (such as cheese, butter, yoghurt, buttermilk, etc.), fermented vegetables (pickles, olives and sauerkraut), sausages, sourdough bread and silage, due to their ability to convert sugars into lactic acid. Of these, dairy products are of outstanding economic importance. Starter cultures used in the dairy industry are mixtures of carefully selected lactic acid bacteria which are added to the milk to fulfil the desired fermentation. Dairy starter cultures must reach high densities in milk in order to produce lactic acid at the required rates for manufacturing. Under these conditions, amino acids supply becomes limitant due to their scarce concentration in milk and to the auxotrophies shown by many starter bacteria. This implies the necessity of a proteolytic system, able to degrade the most abundant protein in milk, casein, into assimilable amino acids and peptides. Casein degradation and utilization require the concerted action of proteinases, peptidases and amino acid and peptide uptake systems. This whole set of enzymes constitutes the proteolytic system. In this article an overview of the recent biochemical and genetic data on the proteolytic system of lactic acid bacteria will be presented.

  12. Drug efflux proteins in multidrug resistant bacteria

    NARCIS (Netherlands)

    vanVeen, HW; Konings, WN

    1997-01-01

    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

  13. Seeing Streptococcus pneumoniae, a Common Killer Bacteria

    DEFF Research Database (Denmark)

    Kjærgaard, Rikke Schmidt; Andersen, Ebbe Sloth

    2014-01-01

    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...

  14. Anchoring of proteins to lactic acid bacteria

    NARCIS (Netherlands)

    Leenhouts, K; Buist, Girbe; Kok, Jan

    1999-01-01

    The anchoring of proteins to the cell surface of lactic acid bacteria (LAB) using genetic techniques is an exciting and emerging research area that holds great promise for a wide variety of biotechnological applications. This paper reviews five different types of anchoring domains that have been exp

  15. Why engineering lactic acid bacteria for biobutanol

    Science.gov (United States)

    The Gram-positive Lactic acid bacteria (LAB) are considered attractive biocatalysts for biomass to biofuels for several reasons. They have GRAS (Generally Recognized As Safe) status that are acceptable in food, feed, and medical applications. LAB are fermentative: selected strains are capable of f...

  16. Metabolic engineering of bacteria for ethanol production

    Energy Technology Data Exchange (ETDEWEB)

    Ingram, L.O.; Gomez, P.F.; Lai, X.; Moniruzzaman, M.; Wood, B.E.; Yomano, L.P.; York, S.W. [Univ. of Florida, Gainesville, FL (United States). Dept. of Microbiology and Cell Science

    1998-04-20

    Technologies are available which will allow the conversion of lignocellulose into fuel ethanol using genetically engineered bacteria. Assembling these into a cost-effective process remains a challenge. The authors` work has focused primarily on the genetic engineering of enteric bacteria using a portable ethanol production pathway. Genes encoding Zymomonas mobilis pyruvate decarboxylase and alcohol dehydrogenase have been integrated into the chromosome of Escherichia coli B to produce strain KO11 for the fermentation of hemicellulose-derived syrups. This organism can efficiently ferment all hexose and pentose sugars present in the polymers of hemicellulose. Klebsiella oxytoca M5A1 has been genetically engineered in a similar manner to produce strain P2 for ethanol production from cellulose. This organism has the native ability to ferment cellobiose and cellotriose, eliminating the need for one class of cellulase enzymes. The optimal pH for cellulose fermentation with this organism is near that of fungal cellulases. The general approach for the genetic engineering of new biocatalysts has been most successful with enteric bacteria thus far. However, this approach may also prove useful with gram-positive bacteria which have other important traits for lignocellulose conversion. Many opportunities remain for further improvements in the biomass to ethanol processes.

  17. Carbohydrate Metabolism in Bifidobacteria: Human Symbiotic Bacteria

    Science.gov (United States)

    Bifidobacterium ssp. constitute up to 90% of microbial gut flora in the infant colon, but considerably less in adults. Carbohydrate metabolism in these bacteria is highly unusual. Data from four Bifidobacterium genomes indicates genes missing from glycolysis, gluconeogenesis, and the TCA cycle, in...

  18. 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

  19. 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...

  20. 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...

  1. 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...

  2. Radiographic markers - A reservoir for bacteria?

    Energy Technology Data Exchange (ETDEWEB)

    Tugwell, Jenna, E-mail: jenna.tugwell@googlemail.co [Department of Radiology, Ysbyty Gwynedd Hospital, Bangor, North Wales (United Kingdom); Maddison, Adele [Nuffield Health, Shrewsbury Hospital (United Kingdom)

    2011-05-15

    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.

  3. Antibiotic-Resistant Bacteria: There is Hope.

    Science.gov (United States)

    Offner, Susan

    1998-01-01

    Argues that reduction in the use of antibiotics would enable antibiotic-sensitive bacteria to flourish. Presents an activity designed to show students how a small, seemingly unimportant difference in doubling time can, over a period of time, make an enormous difference in population size. (DDR)

  4. Multidrug transporters in lactic acid bacteria

    NARCIS (Netherlands)

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

    2005-01-01

    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

  5. 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, probiotic In food industry there is a perceived need for rapid methods for detection and viability a

  6. Bacteria that purify sludge; Des bacteries epuratrices

    Energy Technology Data Exchange (ETDEWEB)

    Peignen-Seraline, P.; Manem, J. [Cirsee, Lyonnaise des Eaux, 92 - Nanterre (France)

    1997-03-01

    Inherent in water purification processes, the formation of sludges is intensively studied. Recently, original bacteria have been observed by searchers: some of them purify water making ``tassels``, others separate them and some of them even participate in the elimination of the first. This research study is described into details and will probably be used in the future at the industrial scale. (O.M.)

  7. Genetics of proteinases of lactic acid bacteria

    NARCIS (Netherlands)

    Kok, Jan; Venema, Gerhardus

    1988-01-01

    Because it is essential for good growth with concomitant rapid acid production, and for the production of flavorous peptides and amino acids, the proteolytic ability of lactic acid bacteria is of crucial importance for reliable dairy product quality. In view of this importance, considerable research

  8. 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.

  9. Genetics of proteinases of lactic acid bacteria

    NARCIS (Netherlands)

    Kok, Jan; Venema, Gerhardus

    Because it is essential for good growth with concomitant rapid acid production, and for the production of flavorous peptides and amino acids, the proteolytic ability of lactic acid bacteria is of crucial importance for reliable dairy product quality. In view of this importance, considerable research

  10. 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

  11. Physiology of Haloalkaliphilic Sulfur-oxidizing Bacteria

    NARCIS (Netherlands)

    Banciu, H.L.

    2004-01-01

    The inorganic sulfur oxidation by obligate haloalkaliphilic chemolithoautotrophs was only recently discovered and investigated. These autotrophic sulfur oxidizing bacteria (SOB), capable of oxidation of inorganic sulfur compounds at moderate to high salt concentration and at high pH, can be divided

  12. Discovering lactic acid bacteria by genomics

    NARCIS (Netherlands)

    Klaenhammer, T; Altermann, E; Arigoni, F; Bolotin, A; Breidt, F; Broadbent, J; Cano, R; Chaillou, S; Deutscher, J; Gasson, M; van de Guchte, M; Guzzo, J; Hartke, A; Hawkins, T; Hols, P; Hutkins, R; Kleerebezem, M; Kok, J; Kuipers, O; Maguin, E; McKay, L; Mills, D; Nauta, A; Overbeek, R; Pel, H; Pridmore, D; Saier, M; van Sinderen, D; Sorokin, A; Steele, J; O'Sullivan, D; de Vos, W; Weimer, B; Zagorec, M; Siezen, R

    2002-01-01

    This review summarizes a collection of lactic acid bacteria that are now undergoing genomic sequencing and analysis. Summaries are presented on twenty different species, with each overview discussing the organisms fundamental and practical significance, environmental habitat, and its role in ferment

  13. Discovering lactic acid bacteria by genomics

    NARCIS (Netherlands)

    Klaenhammer, T.; Altermann, E.; Arigoni, F.; Bolotin, A.; Breidt, F.; Broadbent, J.; Cano, R.; Chaillou, S.; Deutscher, J.; Gasson, M.; Guchte, van de M.; Guzzo, J.; Hartke, A.; Hawkins, T.; Hols, P.; Hutkins, R.; Kleerebezem, M.; Kok, J.; Kuipers, O.; Lubbers, M.; Maguin, E.; McKay, L.; Mills, D.; Nauta, A.; Overbeek, R.; Pel, H.; Pridmore, D.; Saier, M.; Sinderen, van D.; Sorokin, A.; Steele, J.; O'Sullivan, D.; Vos, de W.; Weimer, B.; Zagorec, M.; Siezen, R.

    2002-01-01

    This review summarizes a collection of lactic acid bacteria that are now undergoing genomic sequencing and analysis. Summaries are presented on twenty different species, with each overview discussing the organisms fundamental and practical significance, nvironmental habitat, and its role in fermenta

  14. NSAID enteropathy and bacteria: a complicated relationship.

    Science.gov (United States)

    Syer, Stephanie D; Blackler, Rory W; Martin, Rebeca; de Palma, Giada; Rossi, Laura; Verdu, Elena; Bercik, Premek; Surette, Michael G; Aucouturier, Anne; Langella, Philippe; Wallace, John L

    2015-04-01

    The clinical significance of small intestinal damage caused by nonsteroidal anti-inflammatory drugs (NSAIDs) remains under-appreciated. It occurs with greater frequency than the damage caused by these drugs in the upper gastrointestinal tract, but is much more difficult to diagnose and treat. Although the pathogenesis of NSAID enteropathy remains incompletely understood, it is clear that bacteria, bile, and the enterohepatic circulation of NSAIDs are all important factors. However, they are also interrelated with one another. Bacterial enzymes can affect the cytotoxicity of bile and are essential for enterohepatic circulation of NSAIDs. Gram-negative bacteria appear to be particularly important in the pathogenesis of NSAID enteropathy, possibly through release of endotoxin. Inhibitors of gastric acid secretion significantly aggravate NSAID enteropathy, and this effect is due to significant changes in the intestinal microbiome. Treatment with antibiotics can, in some circumstances, reduce the severity of NSAID enteropathy, but published results are inconsistent. Specific antibiotic-induced changes in the microbiota have not been causally linked to prevention of intestinal damage. Treatment with probiotics, particularly Bifidobacterium, Lactobacillus, and Faecalibacteriaum prausnitzii, has shown promising effects in animal models. Our studies suggest that these beneficial effects are due to colonization by the bacteria, rather than to products released by the bacteria.

  15. Current topics in signal transduction in bacteria

    NARCIS (Netherlands)

    Hellingwerf, K.J.; Crielaard, W.; Teixeira de mattos, M.J.; Hoff, W.D.; Kort, R.; Verhamme, D.T.; Avignone-Rossa, C

    1998-01-01

    Among the signal transfer systems in bacteria two types predominate: two-component regulatory systems and quorum sensing systems. Both types of system can mediate signal transfer across the bacterial cell envelope; however, the signalling molecule typically is not taken up into the cells in the

  16. 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

  17. Molecular approaches to study probiotic bacteria

    NARCIS (Netherlands)

    Vaughan, E.E.; Heilig, G.H.J.; Zoetendal, E.G.; Satokari, R.; Collins, J.K.; Akkermans, A.D.L.; Vos, de W.M.

    2000-01-01

    Functional foods comprising probiotic bacteria are receiving increasing attention from the scientific community and science funding agencies [1]. An essential aspect relating to the functionality of probiotic-based foods is to develop molecular methods to determine the presence, activity and viabili

  18. 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

  19. Magnetotactic bacteria and microjets: A comparative study

    NARCIS (Netherlands)

    Khalil, I.S.M.; Magdanz, Veronika; Sanchez, Samuel; Schmidt, Oliver G.; Misra, Sarthak

    2013-01-01

    We provide a comparative study between two self-propelled microrobots, i.e., magnetotactic bacteria and microjets. This study includes characterization of their fluidic properties (linear and rotational drag coefficients) based on their morphologies and characterization of their magnetic properties

  20. Bacteria in ice may record climate change

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    @@ To many people, bacteria and climate change are like chalk and cheese: the srnallest creature versus one of the biggest phenomena on Earth. Not really.Scientists with the CAS Institute of Tibetan Plateau Research (ITP) and coworkers recently reported that small bugs deposited in ice and snow might tell how our climate has been changing.

  1. 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...

  2. 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

  3. Physiology of Haloalkaliphilic Sulfur-oxidizing Bacteria

    NARCIS (Netherlands)

    Banciu, H.L.

    2004-01-01

    The inorganic sulfur oxidation by obligate haloalkaliphilic chemolithoautotrophs was only recently discovered and investigated. These autotrophic sulfur oxidizing bacteria (SOB), capable of oxidation of inorganic sulfur compounds at moderate to high salt concentration and at high pH, can be divided

  4. Multidrug transporters in lactic acid bacteria

    NARCIS (Netherlands)

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

    2005-01-01

    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

  5. 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 proteo

  6. Anchoring of proteins to lactic acid bacteria

    NARCIS (Netherlands)

    Leenhouts, K; Buist, Girbe; Kok, Jan

    1999-01-01

    The anchoring of proteins to the cell surface of lactic acid bacteria (LAB) using genetic techniques is an exciting and emerging research area that holds great promise for a wide variety of biotechnological applications. This paper reviews five different types of anchoring domains that have been exp

  7. 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...

  8. Heterotrophic bacteria in drinking water distribution system: a review.

    Science.gov (United States)

    Chowdhury, Shakhawat

    2012-10-01

    The microbiological quality of drinking water in municipal water distribution systems (WDS) depends on several factors. Free residual chlorine and/or chloramines are typically used to minimize bacterial recontamination and/or regrowth in WDS. Despite such preventive measures, regrowth of heterotrophic (HPC) and opportunistic bacteria in bulk water and biofilms has yet to be controlled completely. No approach has shown complete success in eliminating biofilms or HPC bacteria from bulk water and pipe surfaces. Biofilms can provide shelter for pathogenic bacteria and protect these bacteria from disinfectants. Some HPC bacteria may be associated with aesthetic and non-life threatening diseases. Research to date has achieved important success in understanding occurrence and regrowth of bacteria in bulk water and biofilms in WDS. To achieve comprehensive understanding and to provide efficient control against bacteria regrowth, future research on bacteria regrowth dynamics and their implications is warranted. In this study, a review was performed on the literature published in this area. The findings and limitations of these papers are summarized. Occurrences of bacteria in WDS, factors affecting bacteria regrowth in bulk water and biofilms, bacteria control strategies, sources of nutrients, human health risks from bacterial exposure, modelling of bacteria regrowth and methods of bacteria sampling and detection and quantification are investigated. Advances to date are noted, and future research needs are identified. Finally, research directions are proposed to effectively control HPC and opportunistic bacteria in bulk water and biofilms in WDS.

  9. Utilisation of Riverine Dom By Coastal Bacteria

    Science.gov (United States)

    Rochelle-Newall, E.; Pizay, M.-D.; Gattuso, J.-P.

    Coastal bacteria were incubated over a period of 8 days in size fractionated, river- ine dissolved organic matter (DOM) collected from the Danish Randersfjord during spring (April) and summer (August) of 2001. Three molecular weight size fractions were used: 0.2 µm filtered (0.2-DOM), >1 kDa (high molecular weight, HMW-DOM) and respira- tion, BR) were measured. The results were compared with parallel control incubations of riverine bacteria in size fractionated riverine DOM and coastal bacteria in size frac- tionated coastal DOM. In all incubations, regardless of initial DOC concentration, size or source, bacterial abundance started low and increased towards the end of the incu- bation. Similarly, bacterial production was initially low, increased during the first few days and then decreased towards the end of the incubation. There were few differences within each incubation type in spring, with the measured parameters failing to exhibit any significant differences between the 0.2-DOM, HMW-DOM or the LMW-DOM incubations. In summer, as in spring, abundance and production were initially low and then increased. BR was higher in summer (ave. 2.2 versus 1.2 µm O2 d-1), potentially due to the higher temperatures (18C versus 6C in spring). The average % DOC removal was also higher in summer (8.9% versus 4.6%) despite relatively similar ini- tial DOC concentrations. Moreover, differences in BA and BP were evident between the sources of DOM in summer. While the coastal bacteria transplanted into riverine HMW-DOM performed similarly to coastal bacteria in coastal HMW-DOM, riverine bacteria in riverine HMW-DOM exhibited higher BA, BP and BR, indicating perhaps a difference in the capabilities of the coastal bacterial assemblage as compared to that of the natural riverine assemblage. Bacterial growth efficiency varied between 26% and 69% and was generally highest in the LMW-DOM incubations. These results fur- ther demonstrate the flexibility of bacteria in their ability to

  10. Invasion of dentinal tubules by oral bacteria.

    Science.gov (United States)

    Love, R M; Jenkinson, H F

    2002-01-01

    Bacterial invasion of dentinal tubules commonly occurs when dentin is exposed following a breach in the integrity of the overlying enamel or cementum. Bacterial products diffuse through the dentinal tubule toward the pulp and evoke inflammatory changes in the pulpo-dentin complex. These may eliminate the bacterial insult and block the route of infection. Unchecked, invasion results in pulpitis and pulp necrosis, infection of the root canal system, and periapical disease. While several hundred bacterial species are known to inhabit the oral cavity, a relatively small and select group of bacteria is involved in the invasion of dentinal tubules and subsequent infection of the root canal space. Gram-positive organisms dominate the tubule microflora in both carious and non-carious dentin. The relatively high numbers of obligate anaerobes present-such as Eubacterium spp., Propionibacterium spp., Bifidobacterium spp., Peptostreptococcus micros, and Veillonella spp.-suggest that the environment favors growth of these bacteria. Gram-negative obligate anaerobic rods, e.g., Porphyromonas spp., are less frequently recovered. Streptococci are among the most commonly identified bacteria that invade dentin. Recent evidence suggests that streptococci may recognize components present within dentinal tubules, such as collagen type I, which stimulate bacterial adhesion and intra-tubular growth. Specific interactions of other oral bacteria with invading streptococci may then facilitate the invasion of dentin by select bacterial groupings. An understanding the mechanisms involved in dentinal tubule invasion by bacteria should allow for the development of new control strategies, such as inhibitory compounds incorporated into oral health care products or dental materials, which would assist in the practice of endodontics.

  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. 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.

  13. Segmentation of Bacteria Image Based on Level Set Method

    Institute of Scientific and Technical Information of China (English)

    WANG Hua; CHEN Chun-xiao; HU Yong-hong; YANG Wen-ge

    2008-01-01

    In biology ferment engineering, accurate statistics of the quantity of bacte-ria is one of the most important subjects. In this paper, the quantity of bacteria which was observed traditionally manuauy can be detected automatically. Image acquisition and pro-cessing system is designed to accomplish image preprocessing, image segmentation and statistics of the quantity of bacteria. Segmentation of bacteria images is successfully real-ized by means of a region-based level set method and then the quantity of bacteria is com-puted precisely, which plays an important role in optimizing the growth conditions of bac-teria.

  14. Observation of polyphosphate granules in cable bacteria

    Science.gov (United States)

    Yang, T.; Nielsen, L. P.; Risgaard-Petersen, N.

    2015-12-01

    Cable bacteria are long filamentous bacteria that capable for long distance electron transport: transporting electrons derived from oxidizing sulfide in anoxic layers, to oxygen at the sediment surface, over a distance of centimeters. Cable bacteria are found in many types of freshwater and marine sediment all over the world, with density of approximately thousands of kilometers per square meter. These long filaments are composed by individual cells closely related to Desulfobulbaceae, connected with a shared outer membrane inside which the strings structure are presumed to be highly conductive. The observed doubling time of cells within the filament is about 20 min, which is among the shortest compare to other bacteria. In these cable cells, we constantly observed polyphosphate granules (poly-P), regardless of cell dimension and shape. This is very interesting since it has long been recognized that the microbial polyP content is low during rapid growth and increases under unfavorable conditions, for example, increasing sulfide concentration and anoxia resulted in a decomposition of poly-P in Beggiatoa. Here, we investigated marine cable bacteria from Netherland and Aarhus Bay, focusing on the poly-P dynamics under various redox conditions. In poly-P stained cells, typically there are two big poly-P granules locate at each polar. In dividing cells, however, the morphology of poly-P changed to six small granules precisely arranged to two row. Moreover, the cells seem be able to continuously divide more than one time without elongation step. These varied poly-P morphologies demonstrate that poly-P is closely related to the cell growth and cell division, by an unknown mechanism. Individual cable filaments were picked up and were exposed to different redox conditions; our primary data indicated the cable cells could suffer anoxic condition better than oxic condition. We also detected decomposition of poly-P under anoxia. These results call for an in-depth examination

  15. Can Protein in Common Skin Bacteria Offer Disease Protection?

    Science.gov (United States)

    ... https://medlineplus.gov/news/fullstory_162192.html Can Protein in Common Skin Bacteria Offer Disease Protection? RoxP ... Swedish researchers report that Propionibacterium acnes secretes a protein called RoxP that protects against bacteria that are ...

  16. Bagged Salads May Be Fertile Ground for Bacteria

    Science.gov (United States)

    ... html Bagged Salads May Be Fertile Ground for Bacteria Study found juices released from damaged leaves encouraged ... Prepackaged salads may promote the growth of salmonella bacteria, researchers report. They found that even slight damage ...

  17. Molecular and chemical dialogues in bacteria-protozoa interactions

    NARCIS (Netherlands)

    Song, C.; Mazzola, M.; Cheng, X.; Oetjen, J.; Alexandrov, T.; Dorrestein, P.; Watrous, J.; Voort, van der M.; Raaijmakers, J.M.

    2015-01-01

    Protozoan predation of bacteria can significantly affect soil microbial community composition and ecosystem functioning. Bacteria possess diverse defense strategies to resist or evade protozoan predation. For soil-dwelling Pseudomonas species, several secondary metabolites were proposed to provide p

  18. Microfluidic Assay to Quantify the Adhesion of Marine Bacteria

    National Research Council Canada - National Science Library

    Arpa-Sancet, M P; Christophis, C; Rosenhahn, A

    2012-01-01

    .... To determine the attachment strength of bacteria to coatings, a microfluidic adhesion assay has been developed which allows probing at which critical wall shear stress bacteria are removed from the surface...

  19. 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. ...

  20. Gut Bacteria Changes After Some Weight-Loss Surgeries

    Science.gov (United States)

    ... https://medlineplus.gov/news/fullstory_165987.html Gut Bacteria Changes After Some Weight-Loss Surgeries Better diversity ... Specifically, the procedure leads to increased diversity of bacteria in the gut, and a microbial population distinct ...

  1. THE ECOLOGY OF BACTERIA IN THE ALFRESCO ATMOSPHERE

    Science.gov (United States)

    This MiniReview is concerned with the sources,flux and the spacial and temporal distributions of culturable airborne bacteria; how meteorological conditions modulate these distributions; and how death, culture media, and experimental devices relate to measuring airborne bacteria....

  2. Bacteriocins and lactic acid bacteria - a minireview | Savadogo ...

    African Journals Online (AJOL)

    African Journal of Biotechnology ... Fermentation of various foods by lactic acid bacteria (LAB) is one of the oldest forms of ... scientific research about lactic acid bacteria as probiotics and their bacteriocins for healthy nutrition of fermented food.

  3. 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.

  4. 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.

  5. Gut Bacteria May Link Diet, Colon Cancer, Study Says

    Science.gov (United States)

    ... https://medlineplus.gov/news/fullstory_163274.html Gut Bacteria May Link Diet, Colon Cancer, Study Says High- ... link appears to be a type of intestinal bacteria, the Boston research team said. Specifically, they looked ...

  6. Study Ties Inflammation, Gut Bacteria to Type 1 Diabetes

    Science.gov (United States)

    ... news/fullstory_163143.html Study Ties Inflammation, Gut Bacteria to Type 1 Diabetes However, it's not yet ... Italian study finds. Those changes include different gut bacteria and inflammation in the small intestine. The differences ...

  7. 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.

  8. Targeted delivery of colloids by swimming bacteria

    Science.gov (United States)

    Koumakis, N.; Lepore, A.; Maggi, C.; Di Leonardo, R.

    2013-01-01

    The possibility of exploiting motile microorganisms as tiny propellers represents a fascinating strategy for the transport of colloidal cargoes. However, delivery on target sites usually requires external control fields to steer propellers and trigger cargo release. The need for a constant feedback mechanism prevents the design of compact devices where biopropellers could perform their tasks autonomously. Here we show that properly designed three-dimensional (3D) microstructures can define accumulation areas where bacteria spontaneously and efficiently store colloidal beads. The process is stochastic in nature and results from the rectifying action of an asymmetric energy landscape over the fluctuating forces arising from collisions with swimming bacteria. As a result, the concentration of colloids over target areas can be strongly increased or depleted according to the topography of the underlying structures. Besides the significance to technological applications, our experiments pose some important questions regarding the structure of stationary probability distributions in non-equilibrium systems. PMID:24100868

  9. Resistant bacteria in stem cell transplant recipients

    Directory of Open Access Journals (Sweden)

    Nucci Marcio

    2002-01-01

    Full Text Available Bacterial infections account for most infections in hematopoietic stem cell transplant recipients. While early mortality reduced dramatically with the introduction of the concept of empirical antibiotic therapy in neutropenic patients, no effect of prophylaxis on the mortality was observed in many studies. On the other hand, antibiotic prophylaxis has resulted in the emergence of resistance among bacteria. In addition, the choice of the antibiotic regimen for empirical therapy and the practices of antibiotic therapy during neutropenia may result in a significant shift in the pattern of bacterial infections. The use of quinolones and vancomycin as prophylaxis, and of carbapenems and vancomycin in the empirical antibiotic therapy, are associated with the appearance of resistant Gram-positive and Gram-negative bacteria. Therefore, hematologists must be aware of the impact of these practices on the emergence of infections due to multi-resistant pathogens, since these infections may be associated with increased mortality.

  10. Intracellular cytoskeletal elements and cytoskeletons in bacteria.

    Science.gov (United States)

    Madkour, Mohamed H F; Mayer, Frank

    2007-01-01

    Within a short period of time after the discovery of bacterial cytoskletons, major progress had been made in areas such as general spatial layout of cytoskeletons, their involvement in a variety of cellfunctions (shape control, cell division, chromosome segregation, cell motility). This progress was achieved by application of advanced investigation techniques. Homologs of eukaryotic actin, tubulin, and intermediate filaments were found in bacteria; cytoskeletal proteins not closely or not at all related to any of these major cytoskeletal proteins were discovered in a number of bacteria such as Mycoplasmas, Spiroplasmas, Spirochetes, Treponema, Caulobacter. A structural role for bacterial elongation factor Tu was indicated. On the basis of this new thinking, new approaches in biotechnology and new drugs are on the way.

  11. Sulfate-reducing bacteria: Microbiology and physiology

    Science.gov (United States)

    Peck, H. D.

    1985-01-01

    The sulfate reducing bacteria, the first nonphotosynthetic anaerobic bacteria demonstrated to contain c type cytochromes, perform electron transfer coupled to phosphorylation. A new bioenergetic scheme for the formation of a proton gradient for growth of Desulfovibrio on organic substrates and sulfate involving vectors electron transfer and consistent with the cellular localization of enzymes and electron transfer components was proposed. Hydrogen is produced in the cytoplasm from organic substrates and, as a permease molecule diffuses rapidly across the cytoplasmic membrane, it is oxidized to protons and electrons by the periplasmic hydrogenase. The electrons only are transferred across the cytoplasmic membrane to the cytoplasm where they are used to reduce sulfate to sulfide. The protons are used for transport or to drive a reversible ATPOSE. The net effect is the transfer of protons across the cytoplasmic membrane with the intervention of a proton pump. This type of H2 cycling is relevant to the bioenergetics of other types of anaerobic microorganisms.

  12. 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.

  13. HERBASPIRILLUM-LIKE BACTERIA IN BANANA PLANTS

    Directory of Open Access Journals (Sweden)

    Weber Olmar B.

    2001-01-01

    Full Text Available Diazotrophic bacteria isolated from banana plants were characterized by morphological and physiological aspects. Three different groups of these plant-bacteria could be established. Two of them showed similarity to species of the Herbaspirillum genus. The third one was different because used only a few carbon substrates and produced water diffusible compounds that fluoresced under UV light. All three bacterial groups were thin rods with mono or bipolar flagella, presented negative reaction in Gram stain, showed catalase activity, were able to reduce nitrate and grew better in semi-solid JNFb medium at 31ºC. The nitrogenase activity was detected in semi-solid N-free JNFb medium and expressed higher values when pH ranged from 6.5 to 7.0 (groups I and II and 6.0 to 6.5 (group III. The diazotrophs isolated from banana plants were distinct from species of Herbaspirillum previously identified in gramineous plants.

  14. Sulfate inhibition effect on sulfate reducing bacteria

    Directory of Open Access Journals (Sweden)

    Sulaiman Al Zuhair

    2008-12-01

    Full Text Available There is an increasing interest in the potential of bacterial sulfate reduction as an alternative method for sulfate removal from wastewater. Under anaerobic conditions, sulfate-reducing bacteria (SRB utilize sulfate to oxidize organic compounds and generate sulfide (S2-. SRB were successfully isolated from sludge samples obtained from a local petroleum refinery, and used for sulfate removal. The effects of initial sulfate concentration, temperature and pH on the rate of bacterial growth and anaerobic sulfate removal were investigated and the optimum conditions were identified. The experimental data were used to determine the parameters of two proposed kinetic model, which take into consideration substrate inhibition effect. Keywords: Sulfate Reducing Bacteria, Sulfate, Kinetic Model, Biotreatement, Inhibition Received: 31 August 2008 / Received in revised form: 18 September 2008, Accepted: 18 September 2008 Published online: 28 September 2008

  15. Biotechnological potential of Clostridium butyricum bacteria

    Directory of Open Access Journals (Sweden)

    Daria Szymanowska-Powałowska

    2014-09-01

    Full Text Available In response to demand from industry for microorganisms with auspicious biotechnological potential, a worldwide interest has developed in bacteria and fungi isolation. Microorganisms of interesting metabolic properties include non-pathogenic bacteria of the genus Clostridium, particularly C. acetobutylicum, C. butyricum and C. pasteurianum. A well-known property of C. butyricum is their ability to produce butyric acid, as well as effectively convert glycerol to 1,3-propanediol (38.2 g/L. A conversion rate of 0.66 mol 1,3-propanediol/mol of glycerol has been obtained. Results of the studies described in the present paper broaden our knowledge of characteristic features of C. butyricum specific isolates in terms of their phylogenetic affiliation, fermentation capacity and antibacterial properties.

  16. Scanning electron microscopy of bacteria Tetrasphaera duodecadis.

    Science.gov (United States)

    Arroyo, E; Enríquez, L; Sánchez, A; Ovalle, M; Olivas, A

    2014-01-01

    This study reports the characterization of the Tetrasphaera duodecadis bacteria and the techniques used therein. In order to evaluate the morphological characteristics of the T. duodecadis bacteria scanning electron microscope (SEM) was used throughout its different growth stages. These microorganisms were grown in vitamin B12 broths with 1% tryptone, 0.2% yeast extract, and 0.1% glucose. The turbidimetric method was employed for the determination of bacterial concentration and growth curve. The SEM results show small agglomerates of 0.8 ± 0.05 µm during the lag phase, and rod-like shapes during the exponential phase with similar shapes in the stationary phase.

  17. Sulfur-oxidizing bacteria in environmental technology.

    Science.gov (United States)

    Pokorna, Dana; Zabranska, Jana

    2015-11-01

    Hydrogen sulfide is widely known as the most undesirable component of biogas that caused not only serious sensoric and toxic problems, but also corrosion of concrete and steel structures. Many agricultural and industrial waste used in biogas production, may contain a large amount of substances that serve as direct precursors to the formation of sulfide sulfur-sources of hydrogen sulfide in the biogas. Biological desulfurization methods are currently promoted to abiotic methods because they are less expensive and do not produce undesirable materials which must be disposed of. The final products of oxidation of sulfides are no longer hazardous. Biological removal of sulfide from a liquid or gaseous phase is based on the activity of sulfur-oxidizing bacteria. They need an oxidizing agent such as an acceptor of electrons released during the oxidation of sulfides-atmospheric oxygen or oxidized forms of nitrogen. Different genera of sulfur-oxidizing bacteria and their technological application are discussed.

  18. Probiotic bacteria induce a 'glow of health'.

    Directory of Open Access Journals (Sweden)

    Tatiana Levkovich

    Full Text Available 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.

  19. Nitrogen acquisition in Agave tequilana from degradation of endophytic bacteria

    OpenAIRE

    Beltran-Garcia, Miguel J.; White, JR; Prado, Fernanda M; Prieto, Katia R.; Yamaguchi, Lydia F.; Torres, Monica S.; Kato, Massuo J.; Medeiros, Marisa H. G.; Di Mascio,Paolo

    2014-01-01

    Plants form symbiotic associations with endophytic bacteria within tissues of leaves, stems, and roots. It is unclear whether or how plants obtain nitrogen from these endophytic bacteria. Here we present evidence showing nitrogen flow from endophytic bacteria to plants in a process that appears to involve oxidative degradation of bacteria. In our experiments we employed Agave tequilana and its seed-transmitted endophyte Bacillus tequilensis to elucidate organic nitrogen transfer from 15N-labe...

  20. Probiotic bacteria in prevention and treatment of diarrhea

    OpenAIRE

    Jasmina Havranek; Šimun Zamberlin; Iva Dolenčić Špehar; Tamara Prtilo; Milna Tudor; Dubravka Samaržija

    2009-01-01

    Probiotic bacteria have beneficial effects in prevention and treatment of different diseases. The results of preventive and therapeutic effect of probiotic bacteria on diarrhea during last ten years are shown in this paper. The greatest preventive and therapeutic effect of probiotic bacteria was identified for acute diarrhea in children caused by rotaviruses. Significant, but slightly lower effect of probiotic bacteria was proved for antibiotic associated diarrhea. Positive effect in preventi...

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

    OpenAIRE

    Froelich, Brett A.; Noble, Rachel T.

    2016-01-01

    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 pol...

  2. Utilization of fumarate by sulfur-reducing bacteria Desulfuromonas sp.

    OpenAIRE

    O. Сhayka; T. Peretjatko; Gudz, S.; HALUSHKA A.

    2016-01-01

    The main goal of the work was to study the utilization of fumarate by sulfur-reducing bacteria Desulfuromonas sp. under different growth conditions and accumulation of hydrogen sulfide by bacteria in the media with sulfur and different electron donors. Sulfur-reducing bacteria Desulfuromonas sp., isolated from soil in Yazivske sulfur deposit, were used in the reasearch. Bacteria were grown in the medium Postgate C without sulfates. The content of hydrogen sulfide was determined by formation o...

  3. Method of detecting and counting bacteria

    Science.gov (United States)

    Picciolo, G. L.; Chappelle, E. W. (Inventor)

    1976-01-01

    An improved method is provided for determining bacterial levels, especially in samples of aqueous physiological fluids. The method depends on the quantitative determination of bacterial adenosine triphosphate (ATP) in the presence of nonbacterial ATP. The bacterial ATP is released by cell rupture and is measured by an enzymatic bioluminescent assay. A concentration technique is included to make the method more sensitive. It is particularly useful where the fluid to be measured contains an unknown or low bacteria count.

  4. Tyramine and Phenylethylamine Biosynthesis by Food Bacteria

    OpenAIRE

    Marcobal, A.; Rivas, Blanca de las; Landete, José María; Tabera, Laura; Muñoz, Rosario

    2012-01-01

    Tyramine poisoning is caused by the ingestion of food containing high levels of tyramine, a biogenic amine. Any foods containing free tyrosine are subject to tyramine formation if poor sanitation and low quality foods are used or if the food is subject to temperature abuse or extended storage time. Tyramine is generated by decarboxylation of the tyrosine through tyrosine decarboxylase (TDC) enzymes derived from the bacteria present in the food. Bacterial TDC have been only unequivocally ident...

  5. [Genetic virulence markers of opportunistic bacteria].

    Science.gov (United States)

    Bondarenko, V M

    2011-01-01

    The analysis of opportunistic bacteria phenotypic and genetic virulence markers indicates that pathogenicity formation is based on a structural modification of bacterial DNA which is linked with migration of interbacterial pathogenicity "islands" genetic determinants. Structural organization features of these mobile genetic elements determine high expression probability, and PCR detection of pathogenicity "islands" determinants that control adhesins, invasins, cytotoxic and cytolitic toxines synthesis may indicate etiopathogenetic significance of clinical isolates.

  6. 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.

  7. Ferrous iron oxidation by anoxygenic phototrophic bacteria

    OpenAIRE

    Widdel, Friedrich; Schnell, Sylvia; Heising, Silke; Ehrenreich, Armin; Assmus, Bernhard; Schink, Bernhard

    1993-01-01

    Natural oxidation of ferrous to ferric iron by bacteria such as Thiobacillus ferrooxidans or Gallionella ferruginea 1, or by chemical oxidation2,3 has previously been thought always to involve molecular oxygen as the electron acceptor. Anoxic photochemical reactions4 6 or a photobiological process involving two photosystems7 9 have also been discussed as mechanisms of ferrous iron oxidation. The knowledge of such processes has implications that bear on our understanding of the origin of Preca...

  8. Physiology of Haloalkaliphilic Sulfur-oxidizing Bacteria

    OpenAIRE

    Banciu, H.L.

    2004-01-01

    The inorganic sulfur oxidation by obligate haloalkaliphilic chemolithoautotrophs was only recently discovered and investigated. These autotrophic sulfur oxidizing bacteria (SOB), capable of oxidation of inorganic sulfur compounds at moderate to high salt concentration and at high pH, can be divided into three genera belonging to the γ subdivision of the Proteobacteria: Thioalkalimicrobium, Thioalkalivibrio and Thioalkalispira. Their taxonomy, metabolic diversity and the potential application...

  9. Bacteria associated with Amblyomma cajennense tick eggs

    Directory of Open Access Journals (Sweden)

    Erik Machado-Ferreira

    2015-01-01

    Full Text Available AbstractTicks represent a large group of pathogen vectors that blood feed on a diversity of hosts. In the Americas, the Ixodidae ticks Amblyomma cajennense are responsible for severe impact on livestock and public health. In the present work, we present the isolation and molecular identification of a group of culturable bacteria associated with A. cajennense eggs from females sampled in distinct geographical sites in southeastern Brazil. Additional comparative analysis of the culturable bacteria from Anocentor nitens, Rhipicephalus sanguineus and Ixodes scapularis tick eggs were also performed. 16S rRNA gene sequence analyses identified 17 different bacterial types identified as Serratia marcescens, Stenotrophomonas maltophilia, Pseudomonas fluorescens, Enterobacter spp., Micrococcus luteus, Ochrobactrum anthropi, Bacillus cereus and Staphylococcus spp., distributed in 12 phylogroups. Staphylococcus spp., especially S. sciuri,was the most prevalent bacteria associated with A. cajennenseeggs, occurring in 65% of the samples and also frequently observed infecting A. nitens eggs. S. maltophilia, S. marcescens and B. cereus occurred infecting eggs derived from specific sampling sites, but in all cases rising almost as pure cultures from infected A. cajennense eggs. The potential role of these bacterial associations is discussed and they possibly represent new targets for biological control strategies of ticks and tick borne diseases.

  10. Anhydrobiosis in bacteria: From physiology to applications

    Indian Academy of Sciences (India)

    Armando Hernández García

    2011-12-01

    Anhydrobiosis is a phenomenon related to the partial or total desiccation of living organisms, keeping their vital functions after rehydration. The desiccated state in prokaryotes has been widely studied, mainly due to the broad spectrum of the anhydrobiosis applications. In this review, we present the basic theoretical concepts related to anhydrobiosis, focusing on bacterial species. An update about desiccation tolerance in bacteria is given; and the general mechanisms of desiccation tolerance and desiccation damage are described. In addition, we show how the study of anhydrobiosis in prokaryotes has established the theoretical and practical basis for the development of the drying technologies. With regard to the desiccation tolerance in bacteria, although many mechanisms remain undiscovered at the molecular level, important research about the physiology of the anhydrobiotic state and its applications has been performed, and here we provide the most recent information about this subject. On the other hand, the most widely used drying technologies and their particular applications in several fields are described (e.g. medicine, agriculture and food industry). Finally, topics on the stability of desiccated bacterial cells are treated, concluding with the necessity of focusing the research on the mathematical modelling of the desiccated state in bacteria.

  11. 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.

  12. Diversity of bacteria at healthy human conjunctiva.

    Science.gov (United States)

    Dong, Qunfeng; Brulc, Jennifer M; Iovieno, Alfonso; Bates, Brandon; Garoutte, Aaron; Miller, Darlene; Revanna, Kashi V; Gao, Xiang; Antonopoulos, Dionysios A; Slepak, Vladlen Z; Shestopalov, Valery I

    2011-07-20

    Ocular surface (OS) microbiota contributes to infectious and autoimmune diseases of the eye. Comprehensive analysis of microbial diversity at the OS has been impossible because of the limitations of conventional cultivation techniques. This pilot study aimed to explore true diversity of human OS microbiota using DNA sequencing-based detection and identification of bacteria. Composition of the bacterial community was characterized using deep sequencing of the 16S rRNA gene amplicon libraries generated from total conjunctival swab DNA. The DNA sequences were classified and the diversity parameters measured using bioinformatics software ESPRIT and MOTHUR and tools available through the Ribosomal Database Project-II (RDP-II). Deep sequencing of conjunctival rDNA from four subjects yielded a total of 115,003 quality DNA reads, corresponding to 221 species-level phylotypes per subject. The combined bacterial community classified into 5 phyla and 59 distinct genera. However, 31% of all DNA reads belonged to unclassified or novel bacteria. The intersubject variability of individual OS microbiomes was very significant. Regardless, 12 genera-Pseudomonas, Propionibacterium, Bradyrhizobium, Corynebacterium, Acinetobacter, Brevundimonas, Staphylococci, Aquabacterium, Sphingomonas, Streptococcus, Streptophyta, and Methylobacterium-were ubiquitous among the analyzed cohort and represented the putative "core" of conjunctival microbiota. The other 47 genera accounted for ocular surface pathogens. The first DNA sequencing-based survey of bacterial population at the conjunctiva have revealed an unexpectedly diverse microbial community. All analyzed samples contained ubiquitous (core) genera that included commensal, environmental, and opportunistic pathogenic bacteria.

  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......RNA genes cell−1. Leaching of bacteria was in the range of 2.5–4.5 × 105 cells ml−1 prior to application of slurry to the three soil textures. After slurry application, leaching increased to 1.1 × 106 cells ml−1 in the loamy sand, 4.9 × 106 cells ml−1 in the sandy loam and 5.0 × 106 cells ml−1 in the loam....... Based on the reported P content of soil bacteria, 0.3–1.8% of the total P leached was present in the bacterial biomass when no slurry was applied, whereas slurry application increased the leaching of P from the bacterial biomass to 3−7.9% of total P leached. Bacterial leaching was related...

  14. Chemotaxis when bacteria remember: drift versus diffusion.

    Directory of Open Access Journals (Sweden)

    Sakuntala Chatterjee

    2011-12-01

    Full Text Available Escherichia coli (E. coli bacteria govern their trajectories by switching between running and tumbling modes as a function of the nutrient concentration they experienced in the past. At short time one observes a drift of the bacterial population, while at long time one observes accumulation in high-nutrient regions. Recent work has viewed chemotaxis as a compromise between drift toward favorable regions and accumulation in favorable regions. A number of earlier studies assume that a bacterium resets its memory at tumbles - a fact not borne out by experiment - and make use of approximate coarse-grained descriptions. Here, we revisit the problem of chemotaxis without resorting to any memory resets. We find that when bacteria respond to the environment in a non-adaptive manner, chemotaxis is generally dominated by diffusion, whereas when bacteria respond in an adaptive manner, chemotaxis is dominated by a bias in the motion. In the adaptive case, favorable drift occurs together with favorable accumulation. We derive our results from detailed simulations and a variety of analytical arguments. In particular, we introduce a new coarse-grained description of chemotaxis as biased diffusion, and we discuss the way it departs from older coarse-grained descriptions.

  15. Predominant bacteria diversity in Chinese traditional sourdough.

    Science.gov (United States)

    Zhang, Guohua; He, Guoqing

    2013-08-01

    The purpose of this study was to identify the major bacteria in Chinese traditional sourdough (CTS). Five CTS samples (Hn-87, Sx-91, Gs-107, Hf-112, and Hr-122) were collected from different Chinese steamed breads shops or private households. The total bacterial DNA was extracted from sourdough samples and sequenced using Illumina Hiseq 2000 system. Illumina tags were assigned to BLASTN server based on 16S rRNA libraries to reveal a genetic profile. Phylogenetic analysis revealed that the bacteria in traditional sourdough samples were dominated by the genera Leuconostoc and Lactobacillus. Beta diversity analysis, principal component analysis, and cluster analysis compared the bacterial differences in traditional sourdough samples. The results showed that Leuconostoc, Lactobacillus, and Weissella were the predominant genera among the 5 samples. This differentiated the sourdoughs into 3 typologies, namely, 1) Gs-107 and Sx-91, 2) Hr-122 and Hn-87, and 3) Hf-112. This study identified 3 unique major bacteria genus in CTS bread ecosystems.

  16. Multitasking SecB chaperones in bacteria

    Directory of Open Access Journals (Sweden)

    Ambre eSala

    2014-12-01

    Full Text Available Protein export in bacteria is facilitated by the canonical SecB chaperone, which binds to unfolded precursor proteins, maintains them in a translocation competent state and specifically cooperates with the translocase motor SecA to ensure their proper targeting to the Sec translocon at the cytoplasmic membrane. Besides its key contribution to the Sec pathway, SecB chaperone tasking is critical for the secretion of the Sec-independent heme-binding protein HasA and actively contributes to the cellular network of chaperones that control general proteostasis in Escherichia coli, as judged by the significant interplay found between SecB and the Trigger Factor, DnaK and GroEL chaperones. Although SecB is mainly a proteobacterial chaperone associated with the presence of an outer membrane and outer membrane proteins, secB-like genes are also found in Gram-positive bacteria as well as in certain phages and plasmids, thus suggesting alternative functions. In addition, a SecB-like protein is also present in the major human pathogen M. tuberculosis where it specifically controls a stress-responsive toxin-antitoxin (TA system. This review focuses on such very diverse chaperone functions of SecB, both in E. coli and in other unrelated bacteria.

  17. Enteric Bacteria and Cancer Stem Cells

    Directory of Open Access Journals (Sweden)

    Jun Sun

    2011-01-01

    Full Text Available Intestinal bacteria can contribute to cell proliferation and cancer development, particularly in chronic infectious diseases in which bacteria and/or bacterial components might interfere with cell function. The number of microbial cells within the gut lumen is estimated to be 100 trillion, which is about 10-times larger than the number of eukaryotic cells in the human body. Because of the complexity of the gut flora, identifying the specific microbial agents related to human diseases remains challenging. Recent studies have demonstrated that the stemness of colon cancer cells is, in part, orchestrated by the microenvironment and is defined by high Wnt activity. In this review article, we will discuss recent progress with respect to intestinal stem cells, cancer stem cells, and the molecular mechanisms of enteric bacteria in the activation of the Wnt pathway. We will also discuss the roles of other pathways, including JAK-STAT, JNK, and Notch, in regulating stem cell niches during bacterial infections using Drosophila models. Insights gained from understanding how host-bacterial interaction during inflammation and cancer may serve as a paradigm for understanding the nature of self-renewal signals.

  18. Bacteria-powered battery on paper.

    Science.gov (United States)

    Fraiwan, Arwa; Choi, Seokheun

    2014-12-21

    Paper-based devices have recently emerged as simple and low-cost paradigms for fluid manipulation and analytical/clinical testing. However, there are significant challenges in developing paper-based devices at the system level, which contain integrated paper-based power sources. Here, we report a microfabricated paper-based bacteria-powered battery that is capable of generating power from microbial metabolism. The battery on paper showed a very short start-up time relative to conventional microbial fuel cells (MFCs); paper substrates eliminated the time traditional MFCs required to accumulate and acclimate bacteria on the anode. Only four batteries connected in series provided desired values of current and potential to power an LED for more than 30 minutes. The battery featured (i) a low-cost paper-based proton exchange membrane directly patterned on commercially available parchment paper and (ii) paper reservoirs for holding the anolyte and the catholyte for an extended period of time. Based on this concept, we also demonstrate the use of paper-based test platforms for the rapid characterization of electricity-generating bacteria. This paper-based microbial screening tool does not require external pumps/tubings and represents the most rapid test platform (<50 min) compared with the time needed by using traditional screening tools (up to 103 days) and even recently proposed MEMS arrays (< 2 days).

  19. Engineering Hybrid Chemotaxis Receptors in Bacteria.

    Science.gov (United States)

    Bi, Shuangyu; Pollard, Abiola M; Yang, Yiling; Jin, Fan; Sourjik, Victor

    2016-09-16

    Most bacteria use transmembrane sensors to detect a wide range of environmental stimuli. A large class of such sensors are the chemotaxis receptors used by motile bacteria to follow environmental chemical gradients. In Escherichia coli, chemotaxis receptors are known to mediate highly sensitive responses to ligands, making them potentially useful for biosensory applications. However, with only four ligand-binding chemotaxis receptors, the natural ligand spectrum of E. coli is limited. The design of novel chemoreceptors to extend the sensing capabilities of E. coli is therefore a critical aspect of chemotaxis-based biosensor development. One path for novel sensor design is to harvest the large natural diversity of chemosensory functions found in bacteria by creating hybrids that have the signaling domain from E. coli chemotaxis receptors and sensory domains from other species. In this work, we demonstrate that the E. coli receptor Tar can be successfully combined with most typical sensory domains found in chemotaxis receptors and in evolutionary-related two-component histidine kinases. We show that such functional hybrids can be generated using several different fusion points. Our work further illustrates how hybrid receptors could be used to quantitatively characterize ligand specificity of chemotaxis receptors and histidine kinases using standardized assays in E. coli.

  20. Bioleaching of marmatite using moderately thermophilic bacteria

    Institute of Scientific and Technical Information of China (English)

    ZHOU Hong-bo; LIU Fei-fei; ZOU Ying-qin; ZENG Xiao-xi; QIU Guan-zhou

    2008-01-01

    The process of bioleaching marmatite using moderately thermophilic bacteria was studied by comparing marmatite leaching performance of mesophiles and moderate thermophiles and valuating the effect of venting capacity as well as pulp density on marmatite leaching performance of moderate thermophiles. The results show that moderate thermophiles have more advantages over mesophilies in bioleaching marmatite at 45℃ and the pulp density of 50g/L, and the zinc extraction efficiency reaches 93.1% in 20d. Aeration agitation can improve the transfer of O2 and CO2 in solution and promote the growth of bacteria and therefore, enhance the leaching efficiency. Under the venting levels of 50, 200 and 800mL/min, the zinc extraction efficiencies by moderate thermophiles are 57.8%, 92.5% and 96.0%, respectively. With the increase of pulp density, the total leaching amount of valuable metals increases, however, the extraction efficiency decreases due to many reasons, such as increasing shear force leading to poorly growth condition for bacteria, etc. The zinc extraction decreases remarkably to 58.9% while the pulp density mounts up 20%.

  1. Anhydrobiosis in bacteria: from physiology to applications.

    Science.gov (United States)

    García, Armando Hernández

    2011-12-01

    Anhydrobiosis is a phenomenon related to the partial or total desiccation of living organisms, keeping their vital functions after rehydration. The desiccated state in prokaryotes has been widely studied, mainly due to the broad spectrum of the anhydrobiosis applications. In this review, we present the basic theoretical concepts related to anhydrobiosis, focusing on bacterial species. An update about desiccation tolerance in bacteria is given; and the general mechanisms of desiccation tolerance and desiccation damage are described. In addition, we show how the study of anhydrobiosis in prokaryotes has established the theoretical and practical basis for the development of the drying technologies. With regard to the desiccation tolerance in bacteria, although many mechanisms remain undiscovered at the molecular level, important research about the physiology of the anhydrobiotic state and its applications has been performed, and here we provide the most recent information about this subject. On the other hand, the most widely used drying technologies and their particular applications in several fields are described (e.g. medicine, agriculture and food industry). Finally, topics on the stability of desiccated bacterial cells are treated, concluding with the necessity of focusing the research on the mathematical modelling of the desiccated state in bacteria.

  2. 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.

  3. Precision genome engineering in lactic acid bacteria.

    Science.gov (United States)

    van Pijkeren, Jan Peter; Britton, Robert A

    2014-08-29

    Innovative new genome engineering technologies for manipulating chromosomes have appeared in the last decade. One of these technologies, recombination mediated genetic engineering (recombineering) allows for precision DNA engineering of chromosomes and plasmids in Escherichia coli. Single-stranded DNA recombineering (SSDR) allows for the generation of subtle mutations without the need for selection and without leaving behind any foreign DNA. In this review we discuss the application of SSDR technology in lactic acid bacteria, with an emphasis on key factors that were critical to move this technology from E. coli into Lactobacillus reuteri and Lactococcus lactis. We also provide a blueprint for how to proceed if one is attempting to establish SSDR technology in a lactic acid bacterium. The emergence of CRISPR-Cas technology in genome engineering and its potential application to enhancing SSDR in lactic acid bacteria is discussed. The ability to perform precision genome engineering in medically and industrially important lactic acid bacteria will allow for the genetic improvement of strains without compromising safety.

  4. 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 r

  5. Taxonomic scheme for the identification of marine bacteria

    Science.gov (United States)

    Oliver, James D.

    1982-06-01

    A recently developed taxonomic scheme for the identification of marine bacteria is presented. The scheme is based on numerous reviews and monographs on marine bacteria, as well as Bergey's Manual of Determinative Bacteriology. While fairly extensive, the scheme is designed to identify marine bacteria using relatively few tests.

  6. A computerised system for the identification of lactic acid bacteria.

    NARCIS (Netherlands)

    Wijtzes, T.; Bruggeman, M.R.; Nout, M.J.R.; Zwietering, M.H.

    1997-01-01

    A generic computerised system for the identification of bacteria was developed. The system is equipped with a key to the identification of lactic acid bacteria. The identification is carried out in two steps. The first step distinguishes groups of bacteria by following a decision tree with general i

  7. Metabolism in bacteria at low temperature: A recent report

    Indian Academy of Sciences (India)

    Dipanwita Sengupta; Madhab K Chattopadhyay

    2013-06-01

    The adaptability of bacteria to extreme cold environments has been demonstrated from time to time by various investigators. Metabolic activity of bacteria at subzero temperatures is also evidenced. Recent studies indicate that bacteria continue both catabolic and anabolic activities at subzero temperatures. Implications of these findings are discussed.

  8. 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

  9. Mucolytic bacteria with increased prevalence in IBD mucosa augment in vitro utilization of mucin by other bacteria

    NARCIS (Netherlands)

    Png, C.W.; Linden, S.K.; Gilshenan, K.S.; Zoetendal, E.G.; McSweeney, C.S.; Sly, L.I.; McGuckin, M.A.; Florin, T.H.

    2010-01-01

    OBJECTIVES: Mucosa-associated bacteria are increased in inflammatory bowel disease (IBD), which suggests the possibility of an increased source of digestible endogenous mucus substrate. We hypothesized that mucolytic bacteria are increased in IBD, providing increased substrate to sustain nonmucolyti

  10. The analysis of bacteria strains and sensitivity of bacteria to antibiotics in acute obstructive cholangitis with suppuration

    Institute of Scientific and Technical Information of China (English)

    顾彬

    2013-01-01

    Objective To analyze the changes of bacteria stains in acute obstructive cholangitis with suppuration(AOSC) and sensitivity of different bacteria strains to antibiotics in recent decade. Methods The data of bacterial

  11. 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

  12. 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

  13. Probiotic bacteria in prevention and treatment of diarrhea

    Directory of Open Access Journals (Sweden)

    Jasmina Havranek

    2009-03-01

    Full Text Available Probiotic bacteria have beneficial effects in prevention and treatment of different diseases. The results of preventive and therapeutic effect of probiotic bacteria on diarrhea during last ten years are shown in this paper. The greatest preventive and therapeutic effect of probiotic bacteria was identified for acute diarrhea in children caused by rotaviruses. Significant, but slightly lower effect of probiotic bacteria was proved for antibiotic associated diarrhea. Positive effect in prevention of traveller’s diarrhea and radiation-induced diarrhea is not significant. Preventive and therapeutic effect on diarrhea is not dependent on the way of probiotic bacteria consumption, by fermented milk, capsule or oral rehydration solution.

  14. Root Associated Bacteria – Friends or Enemies? A Review

    Directory of Open Access Journals (Sweden)

    Gabriela Mihalache

    2015-10-01

    Full Text Available Plant roots, due to their exudates, represent important ecological niches for bacteria, which can influence the plant growth by their both beneficial and deleterious effects. The positive effects of bacteria interaction with the plants roots consist in facilitating the nutrient uptake (N, P, producing phytohormones, enhancing their resistance to biotic and abiotic factors such as pathogenic fungi and bacteria, extreme temperatures, heavy metals, salinity. Regarding the harmful effects of bacteria on plants growth, production of phytotoxins, competition for nutrients or inducing diseases or even plants death represents examples of mechanisms by which bacteria can affect in a negative manner the growth of the plants.

  15. Carotenoid biosynthesis in extremophilic Deinococcus-Thermus bacteria.

    Science.gov (United States)

    Tian, Bing; Hua, Yuejin

    2010-11-01

    Bacteria from the phylum Deinococcus-Thermus are known for their resistance to extreme stresses including radiation, oxidation, desiccation and high temperature. Cultured Deinococcus-Thermus bacteria are usually red or yellow pigmented because of their ability to synthesize carotenoids. Unique carotenoids found in these bacteria include deinoxanthin from Deinococcus radiodurans and thermozeaxanthins from Thermus thermophilus. Investigations of carotenogenesis will help to understand cellular stress resistance of Deinococcus-Thermus bacteria. Here, we discuss the recent progress toward identifying carotenoids, carotenoid biosynthetic enzymes and pathways in some species of Deinococcus-Thermus extremophiles. In addition, we also discuss the roles of carotenoids in these extreme bacteria.

  16. 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...... and carotenoid species also allow the functions of these pigments to be studied in vivo....

  17. Hessian fly-associated bacteria: transmission, essentiality, and composition.

    Directory of Open Access Journals (Sweden)

    Raman Bansal

    Full Text Available Plant-feeding insects have been recently found to use microbes to manipulate host plant physiology and morphology. Gall midges are one of the largest groups of insects that manipulate host plants extensively. Hessian fly (HF, Mayetiola destructor is an important pest of wheat and a model system for studying gall midges. To examine the role of bacteria in parasitism, a systematic analysis of bacteria associated with HF was performed for the first time. Diverse bacteria were found in different developmental HF stages. Fluorescent in situ hybridization detected a bacteriocyte-like structure in developing eggs. Bacterial DNA was also detected in eggs by PCR using primers targeted to different bacterial groups. These results indicated that HF hosted different types of bacteria that were maternally transmitted to the next generation. Eliminating bacteria from the insect with antibiotics resulted in high mortality of HF larvae, indicating that symbiotic bacteria are essential for the insect to survive on wheat seedlings. A preliminary survey identified various types of bacteria associated with different HF stages, including the genera Enterobacter, Pantoea, Stenotrophomonas, Pseudomonas, Bacillus, Ochrobactrum, Acinetobacter, Alcaligenes, Nitrosomonas, Arcanobacterium, Microbacterium, Paenibacillus, and Klebsiella. Similar bacteria were also found specifically in HF-infested susceptible wheat, suggesting that HF larvae had either transmitted bacteria into plant tissue or brought secondary infection of bacteria to the wheat host. The bacteria associated with wheat seedlings may play an essential role in the wheat-HF interaction.

  18. Computational Challenges in Characterization of Bacteria and Bacteria-Host Interactions Based on Genomic Data

    Institute of Scientific and Technical Information of China (English)

    Chao Zhang; Guo-lu Zheng; Shun-Fu Xu; Dong Xu

    2012-01-01

    With the rapid development of next-generation sequencing technologies,bacterial identification becomes a very important and essential step in processing genomic data,especially for metagenomic data.Many computational methods have been developed and some of them are widely used to address the problems in bacterial identification.In this article we review the algorithms of these methods,discuss their drawbacks,and propose future computational methods that use genomic data to characterize bacteria.In addition,we tackle two specific computational problems in bacterial identification,namely,the detection of host-specific bacteria and the detection of disease-associated bacteria,by offering potential solutions as a starting point for those who are interested in the area.

  19. Design and application of the method for isolating magnetotactic bacteria

    Institute of Scientific and Technical Information of China (English)

    XIAO Zhijie; LIAN Bin; CHEN Jun; H. Henry Teng

    2007-01-01

    A simple apparatus was designed to effectively isolate magnetotactic bacteria from soils or sediments based on their magnetotaxis. Through a series of processes including sample incubation, MTB harvesting, isolation, purification and identification, several strains of bacteria were isolated from the samples successfully. By Transmission Electron Microscopy (TEM) and Energy-Dispersive X-ray Analysis (EDXA), these bacteria were certificated to be magnetotactic bacteria. The phylogenetic relationship between the isolated magnetic strains and some known magnetotactic bacteria was inferred by the construction of phylogenetic tree based on 16SrDNA sequences. This apparatus has been proven to have the advantages of being inexpensive, simple to assemble, easy to perform and highly efficient to isolate novel magnetotactic bacteria. The research indicated that the combined approach of harvesting MTB by home-made apparatus and the method of plate colony isolation could purify and isolate magnetotactic bacteria effectively.

  20. Freeing Water from Viruses and Bacteria

    Science.gov (United States)

    2004-01-01

    Four years ago, Argonide Corporation, a company focused on the research, production, and marketing of specialty nano materials, was seeking to develop applications for its NanoCeram[R] fibers. Only 2 nanometers in diameter, these nano aluminum oxide fibers possessed unusual bio-adhesive properties. When formulated into a filter material, the electropositive fibers attracted and retained electro-negative particles such as bacteria and viruses in water-based solutions. This technology caught the interest of NASA as a possible solution for improved water filtration in space cabins. NASA's Johnson Space Center awarded Sanford, Florida-based Argonide a Phase I Small Business Innovation Research (SBIR) contract to determine the feasibility of using the company's filter for purifying recycled space cabin water. Since viruses and bacteria can be carried aboard space cabins by space crews, the ability to detect and remove these harmful substances is a concern for NASA. The Space Agency also desired an improved filter to polish the effluent from condensed and waste water, producing potable drinking water. During its Phase I partnership with NASA, Argonide developed a laboratory-size filter capable of removing greater than 99.9999 percent of bacteria and viruses from water at flow rates more than 200 times faster than virus-rated membranes that remove particles by sieving. Since the new filter s pore size is rather large compared to other membranes, it is also less susceptible to clogging by small particles. In September 2002, Argonide began a Phase II SBIR project with Johnson to develop a full-size cartridge capable of serving a full space crew. This effort, which is still ongoing, enabled the company to demonstrate that its filter media is an efficient absorbent for DNA and RNA.

  1. Fluorescence characterization of clinically-important bacteria.

    Directory of Open Access Journals (Sweden)

    Lewis R Dartnell

    Full Text Available Healthcare-associated infections (HCAI/HAI represent a substantial threat to patient health during hospitalization and incur billions of dollars additional cost for subsequent treatment. One promising method for the detection of bacterial contamination in a clinical setting before an HAI outbreak occurs is to exploit native fluorescence of cellular molecules for a hand-held, rapid-sweep surveillance instrument. Previous studies have shown fluorescence-based detection to be sensitive and effective for food-borne and environmental microorganisms, and even to be able to distinguish between cell types, but this powerful technique has not yet been deployed on the macroscale for the primary surveillance of contamination in healthcare facilities to prevent HAI. Here we report experimental data for the specification and design of such a fluorescence-based detection instrument. We have characterized the complete fluorescence response of eleven clinically-relevant bacteria by generating excitation-emission matrices (EEMs over broad wavelength ranges. Furthermore, a number of surfaces and items of equipment commonly present on a ward, and potentially responsible for pathogen transfer, have been analyzed for potential issues of background fluorescence masking the signal from contaminant bacteria. These include bedside handrails, nurse call button, blood pressure cuff and ward computer keyboard, as well as disinfectant cleaning products and microfiber cloth. All examined bacterial strains exhibited a distinctive double-peak fluorescence feature associated with tryptophan with no other cellular fluorophore detected. Thus, this fluorescence survey found that an emission peak of 340nm, from an excitation source at 280nm, was the cellular fluorescence signal to target for detection of bacterial contamination. The majority of materials analysed offer a spectral window through which bacterial contamination could indeed be detected. A few instances were found of

  2. 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.

  3. Do foliar endophytic bacteria fix nitrogen?

    Science.gov (United States)

    Kueppers, L. M.; Moyes, A. B.; Frank, C.; Pett-Ridge, J.; Carper, D.; Vandehey, N.; O'Neil, J.; Dekas, A.

    2015-12-01

    Endophytic microorganisms - bacteria and fungi that live inside healthy plant tissue - are a relatively unexplored source of functional diversity in natural ecosystems. Prior to modern sequencing technology, detecting uncultured endophytic bacteria and assessing their putative functions was challenging. However, recent work has revealed a remarkable diversity of as yet non-culturable endophytic taxa and is beginning to identify functional roles within plant microbiomes. We recently examined bacterial communities in the foliage of a long-lived, high-elevation conifer species, limber pine (Pinus flexilis), and discovered a community strongly dominated by acetic acid bacteria (Acetobacteraceae), with several taxa closely related to known nitrogen fixers. Given limber pine's status as a pioneer species that is able to grow in low fertility soils, we hypothesized that this bacterial community has a potential functional role in fixing atmospheric nitrogen, providing a source of this limiting nutrient to the host tree. We used the radioisotope 13N2 to confirm that N2 rapidly diffuses into pine needles, where it could potentially be fixed. With an acetylene reduction assay we confirmed nitrogenase enzyme activity inside excised twigs 4 times over a growing season, and estimate potential rates of N2 fixation at 0.1 nmol N2 g needle-1 hr-1. Scaled to the stand level, this N input could be on the order of ~20 mg N m-2 d-1 over a growing season. While these rates are low, the long lifespan of individual trees (~1000 years) makes them biologically meaningful. Still, measured rates of acetylene reduction and bulk 15N2 incorporation are quite variable in space and time. Much work remains to better characterize the plant-microbial interactions in this system, including the rates of nitrogen fixation and their variability over the growing season, across edaphic conditions, among host species, and through plant development; and to determine which community members are responsible

  4. Bacteriophage Infection of Model Metal Reducing Bacteria

    Science.gov (United States)

    Weber, K. A.; Bender, K. S.; Gandhi, K.; Coates, J. D.

    2008-12-01

    Microbially-mediated metal reduction plays a significant role controlling contaminant mobility in aqueous, soil, and sedimentary environments. From among environmentally relevant microorganisms mediating metal reduction, Geobacter spp. have been identified as predominant metal-reducing bacteria under acetate- oxidizing conditions. Due to the significance of these bacteria in environmental systems, it is necessary to understand factors influencing their metabolic physiology. Examination of the annotated finished genome sequence of G. sulfurreducens PCA, G. uraniumreducens Rf4, G. metallireduceans GS-15 as well as a draft genome sequence of Geobacter sp. FRC-32 have identified gene sequences of putative bacteriophage origin. Presence of these sequences indicates that these bacteria are susceptible to phage infection. Polymerase chain reaction (PCR) primer sets designed tested for the presence of 12 of 25 annotated phage-like sequences in G. sulfurreducens PCA and 9 of 17 phage-like sequences in FRC- 32. The following genes were successfully amplified in G. sulfurreducens PCA: prophage type transcription regulator, phage-induced endonuclease, phage tail sheath, 2 phage tail proteins, phage protein D, phage base plate protein, phage-related DNA polymerase, integrase, phage transcriptional regulator, and Cro-like transcription regulator. Nine of the following sequences were present in FRC-32: 4 separate phage- related proteins, phage-related tail component, viron core protein, phage Mu protein, phage base plate, and phage tail sheath. In addition to the bioinformatics evidence, incubation of G. sulfurreducens PCA with 1 μg mL-1 mytomycin C (mutagen stimulating prophage induction) during mid-log phase resulted in significant cell lysis relative to cultures that remained unamended. Cell lysis was concurrent with an increase in viral like particles enumerated using epifluorescent microscopy. In addition, samples collected following this lytic event (~44hours) were

  5. Phosphate solubilizing bacteria around Indian peninsula

    Digital Repository Service at National Institute of Oceanography (India)

    DeSouza, M.J.B.D; Nair, S.; Chandramohan, D

    nitrophenylphosphate by the culture. One mole of nitrophenol is equivalent to 1 atom of phosphorus. The absorbance was read at 418 nm using DU-6 Beckmann spectrophotometer. The activity was expressed as ?mol.Pml-1d-1. The cultures which showed good phosphate... strengthening the fact that the isolates are of marine origin. Maximum activity of 5 ?mol.P.ml-1d-1 was observed for strain P6 in 4.5% NaCl Location Beaches Islands Coasts Offshore Table 1?Phosphate solubilizing bacteria in various niches. No. of cultures...

  6. 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......Oxygen consumption in marine sediments is often coupled to the oxidation of sulphide generated by degradation of organic matter in deeper, oxygen-free layers. Geochemical observations have shown that this coupling can be mediated by electric currents carried by unidentified electron transporters......, electrical cables add a new dimension to the understanding of interactions in nature and may find use in technology development....

  7. Turning bacteria suspensions into a "superfluid"

    CERN Document Server

    López, Héctor Matías; Douarche, Carine; Auradou, Harold; Clément, Eric

    2015-01-01

    The rheological response under simple shear of an active suspension of Escherichia coli is determined in a large range of shear rates and concentrations. The effective viscosity and the time scales characterizing the bacterial organization under shear are obtained. In the dilute regime, we bring evidences for a low shear Newtonian plateau characterized by a shear viscosity decreasing with concentration. In the semi-dilute regime, for particularly active bacteria, the suspension display a "super-fluid" like transition where the viscous resistance to shear vanishes, thus showing that macroscopically, the activity of pusher swimmers organized by shear, is able to fully overcome the dissipative effects due to viscous loss.

  8. 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.

  9. Preservation of bacteria in natural polymers.

    Science.gov (United States)

    Krumnow, April A; Sorokulova, Iryna B; Olsen, Eric; Globa, Ludmila; Barbaree, James M; Vodyanoy, Vitaly J

    2009-08-01

    A new inexpensive and simple method for preserving microorganisms has been developed. Natural polymers of acacia gum and pullulan were used to preserve model bacteria Escherichia coli and Bacillus subtilis via immobilization and storage under various conditions. Formulation of E. coli and B. subtilis in acacia gum significantly increased the viability of both cultures during desiccation at 40 degrees C as well as during the storage at various temperatures and relative humidity. In the ranges of temperatures and humidity used in experiments, the high humidity affected the viability of E. coli more than high temperature. Thermodynamic parameters for E. coli thermal degradation were used for quantification of results and characterization of the preservation process. Viability of B. subtilis in acacia gum polymer was not significantly changed during the storage in the temperature and humidity experiments. The number of viable B. subtilis recovered after storage in pullulan, and in PBS under various humidity conditions was 1-2 logs less in comparison with the number of cells before storage. It was found that acacia gum provides better protection than pullulan for both bacteria during the preservation process.

  10. Rapid detection of bacteria in water

    Science.gov (United States)

    Deininger, Rolf A.; Lee, Ji Y.

    2002-06-01

    A rapid detection of bacteria in water is essential for a timely response. This applies primarily to drinking water, be it bottled water or water from a public supply system, but is equally important for the analysis of water from swimming pools and beaches, and ballast water from oceangoing ships discharging into coastal or inland waters of the US. There are several methods available today for a rapid test including PCR based methods, flow cytometry, and electro chemiluminescence, to name a few. All of the above methods work, but are complicated and/or require expensive equipment and highly trained analysts in a laboratory. The method described here is based on lysing the bacteria after capture on a membrane filter, and measuring the ATP in a luminometer after the addition of luciferin/luciferase. This bioluminescence test can be done onsite, in less than 5 minutes, with equipment that fits onto a clipboard. It is a fast screening test that indicates if there is enough biologically active material in the same to pose a threat to the consumer. If this is the case, an additional step using immunomagnetic separation may be used to identify the responsible organisms. Tests have been done with E. coli 0157:H7, pseudomonas, and logionella. These tests take about 30 minutes each, and allow a quick determination of bacterial threats in a field situation.

  11. Accumulation of swimming bacteria near an interface

    Science.gov (United States)

    Tang, Jay; Li, Guanglai

    2012-11-01

    Microbes inhabit planet earth over billions of years and have adapted to diverse physical environment of water, soil, and particularly at or near interfaces. We focused our attention on the locomotion of Caulobacter crescentus, a singly flagellated bacterium, at the interface of water/solid or water/air. We measured the distribution of a forward swimming strain of C. crescentus near a surface using a three-dimensional tracking technique based on dark field microscopy and found that the swimming bacteria accumulate heavily within a micrometer from the surface. We attribute this accumulation to frequent collisions of the swimming cells with the surface, causing them to align parallel to the surface as they continually move forward. The extent of accumulation at the steady state is accounted for by balancing alignment caused by these collisions with rotational Brownian motion of the micrometer-sized bacteria. We performed a simulation based on this model, which reproduced the measured results. Additional simulations demonstrate the dependence of accumulation on swimming speed and cell size, showing that longer and faster cells accumulate more near a surface than shorter and slower ones do. The overarching goal of our study is to describe interfacial microbial behavior through detailed analysis of their motion. We acknowledge support by NSF PHY 1058375.

  12. Magnetotactic bacteria on Earth and on Mars.

    Science.gov (United States)

    McKay, Christopher P; Friedmann, E Imre; Frankel, Richard B; Bazylinski, Dennis A

    2003-01-01

    Continued interest in the possibility of evidence for life in the ALH84001 Martian meteorite has focused on the magnetite crystals. This review is structured around three related questions: is the magnetite in ALH84001 of biological or non-biological origin, or a mixture of both? does magnetite on Earth provide insight to the plausibility of biogenic magnetite on Mars? could magnetotaxis have developed on Mars? There are credible arguments for both the biological and non-biological origin of the magnetite in ALH84001, and we suggest that more studies of ALH84001, extensive laboratory simulations of non-biological magnetite formation, as well as further studies of magnetotactic bacteria on Earth will be required to further address this question. Magnetite grains produced by bacteria could provide one of the few inorganic traces of past bacterial life on Mars that could be recovered from surface soils and sediments. If there was biogenic magnetite on Mars in sufficient abundance to leave fossil remains in the volcanic rocks of ALH84001, then it is likely that better-preserved magnetite will be found in sedimentary deposits on Mars. Deposits in ancient lakebeds could contain well-preserved chains of magnetite clearly indicating a biogenic origin.

  13. Co-electrospinning of bacteria and viruses

    Science.gov (United States)

    Salalha, Wael; Kuhn, Jonathan; Chervinsky, Shmuel; Zussman, Eyal

    2006-03-01

    Co-electrospinning provides a novel and highly versatile approach towards composite fibers with diameters ranging from a few hundred nm down to 30 nm with embedded elements. In the present work, co-electrospinning of poly(vinyl alcohol) (PVA) and viruses (T7, T4, λ) or bacteria (Escherichia coli, Staphylococcus albus) was carried out. These preparations should have applications for tissue engineering, gene therapy, phage therapy and biosensing. The average diameter of the co-spun nanofibers was about 300 nm. We found that the encapsulated viruses and bacteria manage to survive the electrospinning process, its pressure buildup in the core of the fiber and the electrostatic field in the co-electrospinning process. Approximately 10% of the Escherichia coli and 20% of Staphylococcus albus cells are viable after spinning. Approximately 5% of the bacterial viruses were also viable after the electrospinning. It should be noted that the encapsulated cells and viruses remain stable for two months without a further decrease in number. These results demonstrate the potential of the co-electrospinning process for the encapsulation and immobilization of bio-objects and the possibility of adapting them to technical applications (e.g., bio-chips).

  14. The Role of Bacteria in Iron Biomineralization

    Science.gov (United States)

    Konhauser, K. O.

    2012-04-01

    Bacteria contribute significantly to the development of extremely fine-grained iron mineral precipitates, including oxyhydroxides, carbonates, silicates, phosphates, and sulphides. They influence biomineralization in two significant ways. First, bacteria possess a negative surface charge at pH values characteristic of most natural environments, and in doing so, will become reactive towards metal cations. Once bound, those cations react with more ions, potentially leading to mineral precipitation if a state of supersaturation is achieved. Second, during metabolism, the bacterium affects the redox and saturation states of the fluids around the living cells. In this regard, the microenvironment surrounding each cell can be quite different from the bulk aqueous environment, and as a result, mineral phases form that would not normally be predicted from the geochemistry of the bulk fluid. The impact that iron biomineralization has on elemental cycling in aqueous and sedimentary environments cannot be overstated because many major elemental cycles are strongly linked to iron biomineralizing processes. Although individual 'biomineral' grains are micrometer in scale, if one adds the total amount of biomineralizing biomass, it is not difficult to imagine how they can be significant in partitioning metals from the hydrosphere into the sedimentary system. Indeed, the extensive record of banded iron formation (BIF), from 3.8 to 0.5 billion years ago, testifies to the enormous magnitude of ferric iron sequestration into the sediments throughout much of Earth's history.

  15. Hydrocarbon degradation by Antarctic coastal bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Cavanagh, J.E. [University of Tasmania, Hobart (Australia). Antarctic Cooperative Research Centre; CSIRO Div of Marine Research, Hobart (Australia); University of Tasmania, Hobart (Australia). Dept. of Agricultural Science; Nichols, P.D. [University of Tasmania, Hobart (Australia). Antarctic Cooperative Research Centre; CSIRO Div. of Marine Research, Hobart (Australia); Franzmann, P.D. [CSIRO Land and Water, Wembley (Australia); McMeekin, T.A. [University of Tasmania, Hobart (Australia). Antarctic Cooperative Research Centre

    1999-07-01

    Bacterial cultures obtained through selective enrichment of beach sand collected 60 days and one year after treatment of sites in a pilot oil spill trial conducted at Airport Beach, Vestfold Hills, East Antarctica, were examined for the ability to degrade n-alkanes and phenanthrene. The effects of different hydrocarbon mixtures (Special Antarctic Blend [SAB] and BP-Visco), (fish oil [orange roughy]) and inoculation of replicate sites with water from Organic Lake, (previously shown to contain hydrocarbon-degrading bacteria) on the indigenous microbial population, were examined. Of the cultures obtained, those from sites treated with SAB and BP-Visco degraded n-alkanes most consistently and typically to the greatest extent. Two mixed cultures obtained from samples collected at 60 days and two isolates obtained from these cultures extensively degraded phenanthrene. 1-Hydroxy-naphthoic acid formed the major phenanthrene metabolite. Lower levels of salicyclic acid, 1-naphthol, 1,4-naphthaquinone and phenanthrene 9-10 dihydrodiol were detected in extracts of phenanthrene grown cultures. This study shows that under laboratory conditions indigenous Antarctica bacteria can degrade n-alkanes and the more recalcitrant polycyclic aromatic hydrocarbon, phenanthrene. The enrichment of hydrocarbon degrading microorganisms in Antarctic ecosystems exposed to hydrocarbons, is relevant for the long term fate of hydrocarbon spills in this environment. (author)

  16. Magnetotactic bacteria and magnetosomes - Scope and challenges.

    Science.gov (United States)

    Jacob, Jobin John; Suthindhiran, K

    2016-11-01

    Geomagnetism aided navigation has been demonstrated by certain organisms which allows them to identify a particular location using magnetic field. This attractive technique to recognize the course was earlier exhibited in numerous animals, for example, birds, insects, reptiles, fishes and mammals. Magnetotactic bacteria (MTB) are one of the best examples for magnetoreception among microorganisms as the magnetic mineral functions as an internal magnet and aid the microbe to move towards the water columns in an oxic-anoxic interface (OAI). The ability of MTB to biomineralize the magnetic particles (magnetosomes) into uniform nano-sized, highly crystalline structure with uniform magnetic properties has made the bacteria an important topic of research. The superior properties of magnetosomes over chemically synthesized magnetic nanoparticles made it an attractive candidate for potential applications in microbiology, biophysics, biochemistry, nanotechnology and biomedicine. In this review article, the scope of MTB, magnetosomes and its challenges in research and industrial application have been discussed in brief. This article mainly focuses on the application based on the magnetotactic behaviour of MTB and magnetosomes in different areas of modern science.

  17. Infected neonatal cephalohematomas caused by anaerobic bacteria.

    Science.gov (United States)

    Brook, Itzhak

    2005-01-01

    To present the microbiological and clinical features of six children with infected cephalohematomas (IC) caused by anaerobic bacteria. Presentation of a case series. Polymicrobial infection was present in all instances, where the number of isolates varied from two to four. Two patients had anaerobes only and the other four had mixed flora of strict anaerobes and facultatives. There were 16 bacterial isolates (12 anaerobic, 4 aerobic). The anaerobic isolates were Peptostreptococcus spp. (5 isolates), Prevotella spp. (4), Bacteroides fragilis group (2), and Propionibacterium acnes (1). The aerobic isolates were E. coli (2), Staphylococcus aureus (1) and group B streptococci (1). Blood cultures were positive for three patients. The most common predisposing conditions were vacuum extraction and amnionitis (4 instances of each), instrumental delivery (3), electronic fetal monitoring (2), prolonged delivery (1), and premature rupture of membranes (1). All patients underwent drainage, and four also had surgical incision and drainage of the IC. Osteomyelitis developed in one instance and scalp abscess developed in two patients, both of whom had electronic fetal monitoring. All patients eventually recovered from infection after receiving parenteral and subsequent oral antibiotic therapy for a total of 14-38 days. This study highlights the polymicrobial nature and potential importance of anaerobic bacteria in IC in newborns.

  18. 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.

  19. Epidemiology of nosocomial bacteria resistant to antimicrobials

    Directory of Open Access Journals (Sweden)

    Cristina E. Cabrera

    2011-03-01

    Full Text Available Nosocomial infections are a major challenge for public health because of the high rates of morbidity and mortality generated. It was considered that the excessive or inappropriate use of antibiotics triggers the emergence of resistant strains. Among the clinically important bacteria that most commonly cause nososcomial infections, Gram positive multiresistant pathogens stand out such as methicillin-resistant Staphylococcus aureus (MRSA and vancomycin-resistant Enterococcus spp (VRE, and the Gram negative strains of Klebsiella pneumoniae, Escherichia coli, Pseudomonas spp. and Acinetobacter baumannii producing expanded spectrum b-lactamases (ESbL. This review describes the behavior of the main bacterial pathogens resistant to antibiotics that cause infections in Europe, United States, and Latin America, emphasizing studies of molecular epidemiology on a global scale, including the major epidemiological studies in Colombia. The genetic structure of S. aureus and Enterococcus spp strains shows a clonal characteristic favored by the predominance of a small number of clones with the capacity to spread globally, due probably to cross-infection. However, the introduction of MRSA strains from the community encourages genetic diversity, tending to establish a genetic polyclonal endemic structure in places like the United States. In Gram negative bacteria, the high genetic diversity among isolates, mainly in Latin American countries, indicates that the polyclonal spread is influenced by horizontal transfer of plasmids, by excessive exposure to antibiotics, and prolonged hospital stays. In Colombia, there is information on nosocomial resistant pathogens, but molecular epidemiological information is still scarce.

  20. Epidemiology of nosocomial bacteria resistant to antimicrobials

    Directory of Open Access Journals (Sweden)

    Cristina E Cabrera

    2011-04-01

    Full Text Available Nosocomial infections are a major challenge for public health because of the high rates of morbidity and mortality generated. It was considered that the excessive or inappropriate use of antibiotics triggers the emergence of resistant strains. Among the clinically important bacteria that most commonly cause nososcomial infections, Gram positive multiresistant pathogens stand out such as methicillin-resistant Staphylococcus aureus (MRSA and vancomycin-resistant Enterococcus spp (VRE, and the Gram negative strains of Klebsiella pneumoniae, Escherichia coli, Pseudomonas spp. and Acinetobacter baumannii producing expanded spectrum b-lactamases (ESbL. This review describes the behavior of the main bacterial pathogens resistant to antibiotics that cause infections in Europe, United States, and Latin America, emphasizing studies of molecular epidemiology on a global scale, including the major epidemiological studies in Colombia. The genetic structure of S. aureus and Enterococcus spp strains shows a clonal characteristic favored by the predominance of a small number of clones with the capacity to spread globally, due probably to cross-infection. However, the introduction of MRSA strains from the community encourages genetic diversity, tending to establish a genetic polyclonal endemic structure in places like the United States. In Gram negative bacteria, the high genetic diversity among isolates, mainly in Latin American countries, indicates that the polyclonal spread is influenced by horizontal transfer of plasmids, by excessive exposure to antibiotics, and prolonged hospital stays. In Colombia, there is information on nosocomial resistant pathogens, but molecular epidemiological information is still scarce.

  1. Estuarine ecology of phenanthrene-degrading bacteria

    Science.gov (United States)

    Guerin, William F.; Jones, Galen E.

    1989-08-01

    Phenanthrene degrading bacteria were ubiquitously distributed in waters and sediments of the Great Bay Estuary, NH, as determined using a 14C-phenanthrene mineralization assay. Similar activities were observed in water samples collected in March and June when these were incubated at 18 °C even though ambient water temperatures were 1-4 °C and 10-22 °C, respectively. This observation indicated the constant presence of a mesophilic phenanthrene-degrading bacterial population in the estuary. Among water samples, the highest biodegradation activities were associated with samples collected downstream from a dredging operation which introduced high concentrations of coal tar PAH (polycyclic aromatic hydrocarbons) into the Cocheco River, and in areas receiving PAH from pleasure and commercial boating activities. Mid-estuarine maxima in biodegradation activity during both sampling trips suggested adaptation of the microbial flora to the salinities prevailing in the low turnover, high residence time portion of the Estuary at the time of sampling. Despite the hydrophobicity of phenanthrene, no correlation between biodegradation rates and particulate matter concentrations were observed. Similarly, concentrations of nutrients and dissolved and particulate organic matter correlated poorly with biodegradation rates. Better agreements between 14C-phenanthrene mineralization potentials and plate counts on a phenanthrene/toluene agar (PTA) medium were observed. Phenanthrene biodegradative activities and numbers of culturable bacteria growing on PTA were governed by the degree of previous exposure to PAH.

  2. 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.

  3. 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.

  4. Cyanobacterial Toxin Degrading Bacteria: Who Are They?

    Directory of Open Access Journals (Sweden)

    Konstantinos Ar. Kormas

    2013-01-01

    Full Text Available Cyanobacteria are ubiquitous in nature and are both beneficial and detrimental to humans. Benefits include being food supplements and producing bioactive compounds, like antimicrobial and anticancer substances, while their detrimental effects are evident by toxin production, causing major ecological problems at the ecosystem level. To date, there are several ways to degrade or transform these toxins by chemical methods, while the biodegradation of these compounds is understudied. In this paper, we present a meta-analysis of the currently available 16S rRNA and mlrA (microcystinase genes diversity of isolates known to degrade cyanobacterial toxins. The available data revealed that these bacteria belong primarily to the Proteobacteria, with several strains from the sphingomonads, and one from each of the Methylobacillus and Paucibacter genera. Other strains belonged to the genera Arthrobacter, Bacillus, and Lactobacillus. By combining the ecological knowledge on the distribution, abundance, and ecophysiology of the bacteria that cooccur with toxic cyanobacterial blooms and newly developed molecular approaches, it is possible not only to discover more strains with cyanobacterial toxin degradation abilities, but also to reveal the genes associated with the degradation of these toxins.

  5. Detection of phenols using engineered bacteria

    Science.gov (United States)

    Wise, Arlene A.; Kuske, Cheryl R.; Terwilliger, Thomas C.

    2007-12-04

    Detection of phenols using engineered bacteria. A biosensor can be created by placing a reporter gene under control of an inducible promoter. The reporter gene produces a signal when a cognate transcriptional activator senses the inducing chemical. Creation of bacterial biosensors is currently restricted by limited knowledge of the genetic systems of bacteria that catabolize xenobiotics. By using mutagenic PCR to change the chemical specificity of the Pseudomonas species CF600 DmpR protein, the potential for engineering novel biosensors for detection of phenols has been demonstrated. DmpR, a well-characterized transcriptional activator of the P. CF600's dmp operon mediates growth on simple phenols. Transcription from Po, the promoter heading the dmp operon, is activated when the sensor domain of DmpR interacts with phenol and mono-substituted phenols. By altering the sensor domain of the DmpR, a group of DmpR derivatives that activate transcription of a Po-lacZ fusion in response to eight of the EPA's eleven priority pollutant phenols has been created. The assays and the sensor domain mutations that alter the chemical specificity of DmpR is described.

  6. 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

  7. 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.

  8. 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.

  9. Rapid, quantitative determination of bacteria in water. [adenosine triphosphate

    Science.gov (United States)

    Chappelle, E. W.; Picciolo, G. L.; Thomas, R. R.; Jeffers, E. L.; Deming, J. W. (Inventor)

    1978-01-01

    A bioluminescent assay for ATP in water borne bacteria is made by adding nitric acid to a water sample with concentrated bacteria to rupture the bacterial cells. The sample is diluted with sterile, deionized water, then mixed with a luciferase-luciferin mixture and the resulting light output of the bioluminescent reaction is measured and correlated with bacteria present. A standard and a blank also are presented so that the light output can be correlated to bacteria in the sample and system noise can be substracted from the readings. A chemiluminescent assay for iron porphyrins in water borne bacteria is made by adding luminol reagent to a water sample with concentrated bacteria and measuring the resulting light output of the chemiluminescent reaction.

  10. Challenging the concept of bacteria subsisting on antibiotics.

    Science.gov (United States)

    Walsh, Fiona; Amyes, Sebastian G B; Duffy, Brion

    2013-06-01

    Antibiotic resistance concerns have been compounded by a report that soil bacteria can catabolise antibiotics, i.e. break down and use them as a sole carbon source. To date this has not been verified or reproduced, therefore in this study soil bacteria were screened to verify and reproduce this hypothesis. Survival in high concentrations of antibiotics was initially observed; however, on further analysis these bacteria either did not degrade the antibiotics or they used an intrinsic resistance mechanism (β-lactamases) to degrade the β-lactams, as demonstrated by high-performance liquid chromatography. These results did not verify or reproduce the hypothesis that bacteria subsist on antibiotics or catabolise antibiotics as previously reported. This study identified that bacteria with a catabolising phenotype did not degrade streptomycin or trimethoprim and therefore could not utilise the antibiotics as a nutrient source. Therefore, we conclude that soil bacteria do not catabolise antibiotics.

  11. Phototrophic bacteria and their role in the biogeochemical sulfur cycle

    Science.gov (United States)

    Trueper, H. G.

    1985-01-01

    An essential step that cannot be bypassed in the biogeochemical cycle of sulfur today is dissimilatory sulfate reduction by anaerobic bacteria. The enormous amounts of sulfides produced by these are oxidized again either anaerobically by phototrophic bacteria or aerobically by thiobacilli and large chemotrophic bacteria (Beggiatoa, Thiovulum, etc.). Phototrophic bacteria use sulfide, sulfur, thiosulfate, and sulfite as electron donors for photosynthesis. The most obvious intermediate in their oxidative sulfur metabolism is a long chain polysulfide that appears as so called sulfur globules either inside (Chromatiaceae) or outside (Ectothiorhodospiraceae, Chlorobiaceae, and some of the Rhodospirillaceae) the cells. The assimilation of sulfur compounds in phototrophic bacteria is in principle identical with that of nonphototrophic bacteria. However, the Chlorobiaceae and some of the Chromatiaceae and Rhodospirillaceae, unable to reduce sulfate, rely upon reduced sulfur for biosynthetic purposes.

  12. THE AVAILABILITY OF Mytilus galloprovincialis FOR MONITORING ENTERIC BACTERIA

    Directory of Open Access Journals (Sweden)

    Nüket SĐVRĐ

    2012-01-01

    Full Text Available In this study, the usage of Mediterranean Mussel (Mytilus galloprovincialis Lamarck, 1819 as monitoring organism on enteric bacteria concentrations in heavily polluted marine environments and its use possibilities as water quality improving tool were investigated. The ability of the Mediterranean Mussel to accumulate and purge fecal coliform bacteria investigated in laboratory experiments. First, increase on bacteria concentration was observed on 1,5th hour and sharp decrease rate lasted until 10th hours after that period slow but steady declining bacteria concentration rate was observed and beginning bacteria concentration rate was reached within next 30- 50 hours. Time dependent bacteria concentration reduction has found statistically significant at p<0.001 (r-sq = 0.81. The investigation has also revealed that mussel farming could be established in the over polluted area which is the case only in the different discharge points in the sea.

  13. 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)

  14. Virulence of Entomopathogenic Fungi and Bacteria against Stored Product Pests

    OpenAIRE

    Sevim, Ali; Sevim, Elif; Demirci, Meryem

    2015-01-01

    Virulence of Entomopathogenic Fungi and Bacteria against Stored Product PestsEntomopathogenic microorganisms such as bacteria, fungi, viruses, nematodes and protozoa play an important role for regulation of insect pest populations and, this leads to use these microorganisms as biological control agents against pest species as an alternative to chemicals insecticides. In this study, we tested different bacteria originated from stored product pests and fungi isolated from different sources agai...

  15. Biocidal Energetic Materials for the Destruction of Spore Forming Bacteria

    Science.gov (United States)

    2015-07-01

    L R E P O R T DTRA-TR-13-52 Biocidal Energetic Materials for the Destruction of Spore Forming Bacteria Distribution Statement A...Z39.18 00-07-2015 Technical N/A Biocidal Energetic Materials for the Destruction of Spore Forming Bacteria HDTRA1-10-1-0108 Emily M. Hunt, Ph.D. West...understand the interaction between spore forming bacteria and thermite reactions and products and to exploit energetic material reactions with

  16. Optical trapping and manipulation of viruses and bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Ashkin, A.; Dziedzic, J.M.

    1987-03-20

    Optical trapping and manipulation of viruses and bacteria by laser radiation pressure were demonstrated with single-beam gradient traps. Individual tobacco mosaic viruses and dense oriented arrays of viruses were trapped in aqueous solution with no apparent damage using approximately 120 milliwatts of argon laser power. Trapping and manipulation of single live motile bacteria and Escherichia coli bacteria were also demonstrated in a high-resolution microscope at powers of a few milliwatts.

  17. Diversity, distribution and sources of bacteria in residential kitchens

    OpenAIRE

    2012-01-01

    Bacteria readily colonize kitchen surfaces, and the exchange of microbes between humans and the kitchen environment can impact human health. However, we have a limited understanding of the overall diversity of these communities, how they differ across surfaces, and sources of bacteria to kitchen surfaces. Here we used high-throughput sequencing of the 16S rRNA gene to explore biogeographical patterns of bacteria across >80 surfaces within the kitchens of each of four households. In total, 34 ...

  18. Biodegradation of Mixed PAHs by PAH-Degrading Endophytic Bacteria

    OpenAIRE

    Xuezhu Zhu; Xue Ni; Michael Gatheru Waigi; Juan Liu; Kai Sun; Yanzheng Gao

    2016-01-01

    Endophytic bacteria can promote plant growth, induce plant defence mechanisms, and increase plant resistance to organic contaminants. The aims of the present study were to isolate highly PAH-degrading endophytic bacteria from plants growing at PAH-contaminated sites and to evaluate the capabilities of these bacteria to degrade polycyclic aromatic hydrocarbons (PAHs) in vitro, which will be beneficial for re-colonizing target plants and reducing plant PAH residues through the inoculation of pl...

  19. Bacteria resitnce to antibiotics: an analysis of hospital conduct

    OpenAIRE

    Oliveira, Andrea Luiza de; CESUMAR

    2007-01-01

    The objective of this paper is to identify the main medical-hospital practices that aggravate bacteria resistance and reflect the indiscriminate use of antibiotics leaging to hospital infections. To that aim, we present general concepts on antibiotic therapy. We analyse the development of induced bacteria resistance by the indiscriminate use of antibiotics, describing the genetic and biochemical resistance mechanisms. We focus on the incidence of bacteria resistance in hospital in relation to...

  20. Antibiotic-resistant soil bacteria in transgenic plant fields

    OpenAIRE

    Demaneche, S.; Sanguin, H.; Pote, J.; Navarro, Elisabeth; Bernillon, D.; Mavingui, P.; Wildi, W.; Vogel, T M; Simonet, P

    2008-01-01

    Understanding the prevalence and polymorphism of antibiotic resistance genes in soil bacteria and their potential to be transferred horizontally is required to evaluate the likelihood and ecological (and possibly clinical) consequences of the transfer of these genes from transgenic plants to soil bacteria. In this study, we combined culture-dependent and -independent approaches to study the prevalence and diversity of bla genes in soil bacteria and the potential impact that a 110-successive-y...

  1. Antibiotic-resistant soil bacteria in transgenic plant fields

    OpenAIRE

    Demanèche, Sandrine; Sanguin, Hervé; Poté, John; Navarro, Elisabeth; Bernillon, Dominique; Mavingui, Patrick; Wildi, Walter; Vogel, Timothy M.; Simonet, Pascal

    2008-01-01

    Understanding the prevalence and polymorphism of antibiotic resistance genes in soil bacteria and their potential to be transferred horizontally is required to evaluate the likelihood and ecological (and possibly clinical) consequences of the transfer of these genes from transgenic plants to soil bacteria. In this study, we combined culture-dependent and -independent approaches to study the prevalence and diversity of bla genes in soil bacteria and the potential impact that a 10-successive-ye...

  2. Antibiotic-resistant soil bacteria in transgenic plant fields

    OpenAIRE

    Demanèche, Sandrine; Sanguin, Hervé; Poté, John; Navarro, Elisabeth; Bernillon, Dominique; Mavingui, Patrick; Wildi, Walter; Vogel, Timothy,; Simonet, Pascal

    2008-01-01

    Understanding the prevalence and polymorphism of antibiotic resistance genes in soil bacteria and their potential to be transferred horizontally is required to evaluate the likelihood and ecological (and possibly clinical) consequences of the transfer of these genes from transgenic plants to soil bacteria. In this study, we combined culture-dependent and -independent approaches to study the prevalence and diversity of bla genes in soil bacteria and the potential impact that a 10-successive-y...

  3. High motility reduces grazing mortality of planktonic bacteria

    DEFF Research Database (Denmark)

    Matz, Carsten; Jurgens, K.

    2005-01-01

    We tested the impact of bacterial swimming speed on the survival of planktonic bacteria in the presence of protozoan grazers. Grazing experiments with three common bacterivorous nanoflagellates revealed low clearance rates for highly motile bacteria. High-resolution video microscopy demonstrated ......(3), >50 mum s(-1)) illustrated the combined protective action of small cell size and high motility. Our findings suggest that motility has an important adaptive function in the survival of planktonic bacteria during protozoan grazing....

  4. Detachment and flow cytometric quantification of seagrass-associated bacteria.

    Science.gov (United States)

    Trevathan-Tackett, Stacey; Macreadie, Peter; Ralph, Peter; Seymour, Justin

    2014-07-01

    A new protocol was developed to detach bacteria from seagrass tissue and subsequently enumerate cells using flow cytometry (FCM). A method involving addition of the surfactant Tween 80 and vortexing resulted in maximum detachment efficiency of seagrass attached bacteria, providing a robust protocol for precisely enumerating seagrass-associated bacteria with FCM. Using this approach we detected cell concentrations between 2.0×10(5) and 8.0×10(6)cells mg(-1) DW tissue.

  5. Identification of bacteria in scuba divers' rinse tanks.

    Science.gov (United States)

    Washburn, Brian K; Levin, Andrew E; Hennessy, Kristen; Miller, Michael R

    2010-01-01

    Scuba divers typically rinse equipment in communal tanks. Studies show these tanks are contaminated with bacteria, but the types of bacteria have not been studied. We sought to identify bacteria in rinse tanks at a dive facility at San Pedro, Belize, to determine the origin of the bacteria and determine whether the bacteria represented potential threats to human health. The identity of bacteria was investigated using reverse line blot (RLB) assays based on 28 different rDNA probes designed to detect known pathogens of sepsis, as well as by sequencing 23S rDNA from isolates and performing VITEK identification of several isolates. Based on the identities of bacteria in divers' rinse tanks, many likely originate from the ocean, and others likely originate from the divers themselves. None of the bacteria identified would be considered overt human pathogens. However, some of the bacteria found in the tanks are known to be associated with unsanitary conditions and can cause opportunistic infections, which may pose health problems to some individuals. Rinsing scuba equipment in communal tanks has the potential to transmit disease among some divers. Equipment, especially regulators and masks, should be rinsed/cleaned individually and not be placed in communal tanks.

  6. Isolation and identification of marine fish tumour (odontoma) associated bacteria

    Institute of Scientific and Technical Information of China (English)

    Ramalingam Vijayakumar; Kuzhanthaivel Raja; Vijayapoopathi Singaravel; Ayyaru Gopalakrishnan

    2015-01-01

    Objective: To identify fish tumour associated bacteria. Methods: The marine fish Sphyraena jello with odontoma was collected from in Tamil Nadu (Southeast India), and tumour associated bacteria were isolated. Then the isolated bacteria were identified based on molecular characters. Results: A total of 4 different bacterial species were isolated from tumour tissue. The bacterial species were Bacillus sp., Pontibacter sp., Burkholderia sp. and Macrococcus sp., and the sequences were submitted in DNA Data Bank of Japan with accession numbers of AB859240, AB859241, AB859242 and AB859243 respectively. Conclusions: Four different bacterial species were isolated from Sphyraena jello, but the role of bacteria within tumour needs to be further investigated.

  7. Quantification and qualification of bacteria trapped in chewed gum.

    Science.gov (United States)

    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 remove them from the oral cavity. To test this hypothesis, we developed two methods to quantify numbers of bacteria trapped in chewed gum. In the first method, known numbers of bacteria were finger-chewed into gum and chewed gums were molded to standard dimensions, sonicated and plated to determine numbers of colony-forming-units incorporated, yielding calibration curves of colony-forming-units retrieved versus finger-chewed in. In a second method, calibration curves were created by finger-chewing known numbers of bacteria into gum and subsequently dissolving the gum in a mixture of chloroform and tris-ethylenediaminetetraacetic-acid (TE)-buffer. The TE-buffer was analyzed using quantitative Polymerase-Chain-Reaction (qPCR), yielding calibration curves of total numbers of bacteria versus finger-chewed in. Next, five volunteers were requested to chew gum up to 10 min after which numbers of colony-forming-units and total numbers of bacteria trapped in chewed gum were determined using the above methods. The qPCR method, involving both dead and live bacteria yielded higher numbers of retrieved bacteria than plating, involving only viable bacteria. Numbers of trapped bacteria were maximal during initial chewing after which a slow decrease over time up to 10 min was observed. Around 10(8) bacteria were detected per gum piece depending on the method and gum considered. The number of species trapped in chewed gum increased with chewing time. Trapped bacteria were clearly visualized in chewed gum using scanning-electron-microscopy. Summarizing, using novel methods to quantify and qualify oral bacteria trapped in chewed gum, the hypothesis is confirmed that chewing of gum can trap

  8. Bacterias, fuente de energía para el futuro

    Directory of Open Access Journals (Sweden)

    Alba Ayde Romero Mejía

    2012-06-01

    Full Text Available This paper presents a family of bacteria called Geobacter that have the ability to produce power as a renewable source in a microbial fuel cell. These bacteria can completely oxidize organic compounds using different elements or substances as electron acceptors. The paper addresses key features of the bacteria, the mechanisms used to harness the electricity generated and an approximation of the system required to become a competitive source of renewable energy. The results show a comparative analysis of sources of conventional and unconventional energy with respect to the Geobacter family of bacteria.

  9. A Comprehensive Review of Aliphatic Hydrocarbon Biodegradation by Bacteria.

    Science.gov (United States)

    Abbasian, Firouz; Lockington, Robin; Mallavarapu, Megharaj; Naidu, Ravi

    2015-06-01

    Hydrocarbons are relatively recalcitrant compounds and are classified as high-priority pollutants. However, these compounds are slowly degraded by a large variety of microorganisms. Bacteria are able to degrade aliphatic saturated and unsaturated hydrocarbons via both aerobic and anaerobic pathways. Branched hydrocarbons and cyclic hydrocarbons are also degraded by bacteria. The aerobic bacteria use different types of oxygenases, including monooxygenase, cytochrome-dependent oxygenase and dioxygenase, to insert one or two atoms of oxygen into their targets. Anaerobic bacteria, on the other hand, employ a variety of simple organic and inorganic molecules, including sulphate, nitrate, carbonate and metals, for hydrocarbon oxidation.

  10. Liquid-nitrogen cryopreservation of three kinds of autotrophicbioleaching bacteria

    Institute of Scientific and Technical Information of China (English)

    WU Xue-ling; XIN Xiao-hong; JIANG Ying; LIANG Ren-xing; YUAN Peng; FANG Cheng-xiang

    2008-01-01

    Three kinds of autotrophic bioleaching bacteria strains,including mesophilic and acidophilic ferrous ion-oxidizing bacteria Acidithiobacillus ferrooxidans (A.ferrooxidans),mesophilic and acidophilic sulfur-oxidizing bacteria Acidithiobacillus thiooxidans (A.thiooxidans),and moderately thermophilic sulfur-oxidizing bacteria Acidianus brierleyi,were cryopreserved in liquid nitrogen and their ferrous ion- or sulfur-oxidizing activities were investigated and compared with the original ones.The results revealed that ferrous ion/sulfur oxidation activities of the strains were almost equal before and after cryopreservation.Glycerin was used as cryoprotective agent.In conclusion,liquid-nitrogen cryopreservation is a simple and effective method for autotrophic bioleaching microorganisms.

  11. Water quality indicators: bacteria, coliphages, enteric viruses.

    Science.gov (United States)

    Lin, Johnson; Ganesh, Atheesha

    2013-12-01

    Water quality through the presence of pathogenic enteric microorganisms may affect human health. Coliform bacteria, Escherichia coli and coliphages are normally used as indicators of water quality. However, the presence of above-mentioned indicators do not always suggest the presence of human enteric viruses. It is important to study human enteric viruses in water. Human enteric viruses can tolerate fluctuating environmental conditions and survive in the environment for long periods of time becoming causal agents of diarrhoeal diseases. Therefore, the potential of human pathogenic viruses as significant indicators of water quality is emerging. Human Adenoviruses and other viruses have been proposed as suitable indices for the effective identification of such organisms of human origin contaminating water systems. This article reports on the recent developments in the management of water quality specifically focusing on human enteric viruses as indicators.

  12. Isolation and Identification of Nitrite- oxidizing Bacteria

    Institute of Scientific and Technical Information of China (English)

    Yulong; CHEN; Wenyong; TAN; Da; YANG

    2015-01-01

    In order to select the strain that can degrade nitrite,we use the screening plate with nitrite as the sole nitrogen source to select the strain with ability to degrade nitrite,and get a strain with nitrite degrading capacity from the silt of shrimp farming pond in Hepu City,Guangxi Zhuang Autonomous Region. By identifying the strain from colony morphology,physiological and biochemical characteristics and 16 S r RNA sequence,we finally get a bacteria strain that can degrade nitrite,and this strain can grow well on the culture medium with nitrite concentration of 2 g / L. Based on morphology,nitrogen source requirements and evolutionary tree analysis of the above 16 S r RNA sequence,it is found that this strain belongs to Pannonibacter phragmitetus. According to the screening location,it is named HPPP007 strain.

  13. 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.

  14. Detection of bacteria with bioluminescent reporter bacteriophage.

    Science.gov (United States)

    Klumpp, Jochen; Loessner, Martin J

    2014-01-01

    Bacteriophages are viruses that exclusively infect bacteria. They are ideally suited for the development of highly specific diagnostic assay systems. Bioluminescent reporter bacteriophages are designed and constructed by integration of a luciferase gene in the virus genome. Relying on the host specificity of the phage, the system enables rapid, sensitive, and specific detection of bacterial pathogens. A bioluminescent reporter phage assay is superior to any other molecular detection method, because gene expression and light emission are dependent on an active metabolism of the bacterial cell, and only viable cells will yield a signal. In this chapter we introduce the concept of creating reporter phages, discuss their advantages and disadvantages, and illustrate the advances made in developing such systems for different Gram-negative and Gram-positive pathogens. The application of bioluminescent reporter phages for the detection of foodborne pathogens is emphasized.

  15. 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.

  16. Dynamics of swimming bacteria at complex interfaces

    CERN Document Server

    Lopez, Diego

    2014-01-01

    Flagellated bacteria exploiting helical propulsion are known to swim along circular trajectories near surfaces. Fluid dynamics predicts this circular motion to be clockwise (CW) above a rigid surface (when viewed from inside the fluid) and counter-clockwise (CCW) below a free surface. Recent experimental investigations showed that complex physicochemical processes at the nearby surface could lead to a change in the direction of rotation, both at solid surfaces absorbing slip-inducing polymers and interfaces covered with surfactants. Motivated by these results, we use a far-field hydrodynamic model to predict the kinematics of swimming near three types of interfaces: clean fluid-fluid interface, slipping rigid wall, and a fluid interface covered by incompressible surfactants. Representing the helical swimmer by a superposition of hydrodynamic singularities, we first show that in all cases the surfaces reorient the swimmer parallel to the surface and attract it, both of which are a consequence of the Stokes dip...

  17. The Respiratory Chain of Alkaliphilic Bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Terry Ann Krulwich

    2008-01-29

    Alkaliphilic bacteria that grow at extremely high pH are confronted by particular bioenergetic problems in carrying out oxidative phosphorylation. This project focused on the properties and adaptations of the respiratory chain. The respiratory chain as a whole, the redox poises of its components and several individual complexes of the respiratory chain of alkaliphilic Bacillus pseudofirmus OF4 have been characterized as part of this project and, importantly, this project has helped support the development of genetic tools that make B. pseudofirmus OF4 the most genetically tractable and, hence, most bioenergetically characterized extreme alkaliphile. Evidence has been obtained for a pivotal role of the cca3-type terminal oxidase in oxidative phosphorylation, especially at high pH and motifs that may be relevant to that special role have been identified.

  18. [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.

  19. [Travellers and multi-drug resistance bacteria].

    Science.gov (United States)

    Takeshita, Nozomi

    2012-02-01

    The number of international travellers has increased. There is enormous diversity in medical backgrounds, purposes of travel, and travelling styles among travellers. Travellers are hospitalized abroad because of exotic and common diseases via medical tourism. This is one way of transporting and importing human bacteria between countries, including multi-drug resistant organisms. In developing countries, the antimicrobial resistance in Shigella sp. and Salmonella sp. have been a problem, because of this trend, the first choice of antibiotics has changed in some countries. Community acquired infections as well as hospital acquired infections with MRSA, multi-drug resistance (MDR) Pseudomonas aeruginosa, and ESBL have been a problem. This review will discuss the risk of MDR bacterial infectious diseases for travellers.

  20. Mutagenic effects of heavy ions in bacteria

    Science.gov (United States)

    Horneck, G.; Krasavin, E. A.; Kozubek, S.

    1994-10-01

    Various mutagenic effects by heavy ions were studied in bacteria, irradiated at accelerators in Dubna, Prague, Berkeley or Darmstadt. Endpoints investigated are histidine reversion (B. subtilis, S. typhimurium), azide resistance (B. subtilis), mutation in the lactose operon (E. coli), SOS chromotest (E. coli) and λ-prophage induction (E. coli). It was found that the cross sections of the different endpoints show a similar dependence on energy. For light ions (Z = 26) it increases with energy up to a maximum or saturation. The increment becomes steeper with increasing Z. This dependence on energy suggests a ``mutagenic belt'' inside the track that is restricted to an area where the density of departed energy is low enough not to kill the cell, but high enough to induce mutations.

  1. Automatic tracking of Escherichia coli bacteria.

    Science.gov (United States)

    Xie, Jun; Khan, Shahid; Shah, Mubarak

    2008-01-01

    In this paper, we present an automatic method for estimating the trajectories of Escherichia coli bacteria from in vivo phase-contrast microscopy videos. To address the low-contrast boundaries in cellular images, an adaptive kernel-based technique is applied to detect cells in sequence of frames. Then a novel matching gain measure is introduced to cope with the challenges such as dramatic changes of cells' appearance and serious overlapping and occlusion. For multiple cell tracking, an optimal matching strategy is proposed to improve the handling of cell collision and broken trajectories. The results of successful tracking of Escherichia coli from various phase-contrast sequences are reported and compared with manually-determined trajectories, as well as those obtained from existing tracking methods. The stability of the algorithm with different parameter values is also analyzed and discussed.

  2. Antenna organization in green photosynthetic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Blankenship, R.E.

    1987-01-01

    This project is concerned with the structure and function of the unique antenna system found in the green photosynthetic bacteria. The antenna system in these organisms is contained within a vesicle known as a chlorosome, which is attached to the cytoplasmic side of the cell membrane. Additional antenna pigments and reaction centers are contained in integral membrane proteins. Energy absorbed by the bacteriochlorophyll c (BChl c) pigments in the chlorosome is transferred via a baseplate'' array of BChl a antenna pigments into the membrane and to the reaction center. A schematic model of chlorosome structure is shown. This project is aimed at increasing our understanding of the organization of the pigments in the chlorosome and how the antenna system functions.

  3. Exopolysaccharides from sourdough lactic acid bacteria.

    Science.gov (United States)

    Galle, Sandra; Arendt, Elke K

    2014-01-01

    The use of sourdough improves the quality and increases the shelf life of bread. The positive effects are associated with metabolites produced by lactic acid bacteria (LAB) during sourdough fermentation, including organic acids, exopolysaccharides (EPS), and enzymes. EPS formed during sourdough fermentation by glycansucrase activity from sucrose influence the viscoelastic properties of the dough and beneficially affect the texture and shelf life (in particular, starch retrogradation) of bread. Accordingly, EPS have the potential to replace hydrocolloids currently used as bread improvers and meet so the consumer demands for a reduced use of food additives. In this review, the current knowledge about the functional aspects of EPS formation by sourdough LAB especially in baking applications is summarized.

  4. Pyrite oxidation by Acidithiobacillus ferrooxidans bacteria

    Directory of Open Access Journals (Sweden)

    Savić Dragiša S.

    2005-01-01

    Full Text Available The kinetic model of pyrite particle dissolution by the action of bacteria Acidithiobacillus ferrooxidans in a shaken Erlenmeyer flask was presented. The model agreed well with the experimental data for the extracted iron and the number of cells in the liquid phase. The specific growth rate of the adsorbed cells was evaluated (μA = 1,6 d-1 by fitting the experimental data to the model curve. Also, the relevance of the two proposed mechanisms for the bacterial dissolution of sulphide (direct and indirect was discussed, indicating that the indirect one was dominant. The adsorption process of A. ferrooxidans to the pyrite surface was well correlated by a Langmuir type isotherm.

  5. 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.

  6. Bacteriocins active against plant pathogenic bacteria.

    Science.gov (United States)

    Grinter, Rhys; Milner, Joel; Walker, Daniel

    2012-12-01

    Gram-negative phytopathogens cause significant losses in a diverse range of economically important crop plants. The effectiveness of traditional countermeasures, such as the breeding and introduction of resistant cultivars, is often limited by the dearth of available sources of genetic resistance. An alternative strategy to reduce loss to specific bacterial phytopathogens is to use narrow-spectrum protein antibiotics such as colicin-like bacteriocins as biocontrol agents. A number of colicin-like bacteriocins active against phytopathogenic bacteria have been described previously as have strategies for their application to biocontrol. In the present paper, we discuss these strategies and our own recent work on the identification and characterization of candidate bacteriocins and how these potent and selective antimicrobial agents can be effectively applied to the control of economically important plant disease.

  7. Bacteria,inflammation,and colon cancer

    Institute of Scientific and Technical Information of China (English)

    Liying Yang; Zhiheng Pei

    2006-01-01

    Our relationship with the colonic bacterial flora has long been viewed as benign,but recent studies suggest that this symbiosis has risks as well as benefits.This relationship requires that the host not only provide a supportive environment for the symbiotic bacteria,but also actively maintain intact mechanisms for properly managing the physiologic stresses that are closely associated with the symbiont's essential survival functions.Failure to do so breaches the hostsymbiont contract,and can result in serious effects on the health of the host.Recent investigations that employ several knockout mouse models reveal the consequences of genetic deficiency in the host regarding these mechanisms,and the latent,pro-inflammatory,tumorigenic nature of normal bacterial flora.Further study of the interactions between normal bacterial flora and hosts could shed light on the etiologies and pathogenesis of inflammatory diseases and related cancers,with implications for human health.

  8. 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.

  9. Chromosome replication and segregation in bacteria.

    Science.gov (United States)

    Reyes-Lamothe, Rodrigo; Nicolas, Emilien; Sherratt, David J

    2012-01-01

    In dividing cells, chromosome duplication once per generation must be coordinated with faithful segregation of newly replicated chromosomes and with cell growth and division. Many of the mechanistic details of bacterial replication elongation are well established. However, an understanding of the complexities of how replication initiation is controlled and coordinated with other cellular processes is emerging only slowly. In contrast to eukaryotes, in which replication and segregation are separate in time, the segregation of most newly replicated bacterial genetic loci occurs sequentially soon after replication. We compare the strategies used by chromosomes and plasmids to ensure their accurate duplication and segregation and discuss how these processes are coordinated spatially and temporally with growth and cell division. We also describe what is known about the three conserved families of ATP-binding proteins that contribute to chromosome segregation and discuss their inter-relationships in a range of disparate bacteria.

  10. Origin and fate of repeats in bacteria.

    Science.gov (United States)

    Achaz, G; Rocha, E P C; Netter, P; Coissac, E

    2002-07-01

    We investigated 53 complete bacterial chromosomes for intrachromosomal repeats. In previous studies on eukaryote chromosomes, we proposed a model for the dynamics of repeats based on the continuous genesis of tandem repeats, followed by an active process of high deletion rate, counteracted by rearrangement events that may prevent the repeats from being deleted. The present study of long repeats in the genomes of Bacteria and Archaea suggests that our model of interspersed repeats dynamics may apply to them. Thus the duplication process might be a consequence of very ancient mechanisms shared by all three domains. Moreover, we show that there is a strong negative correlation between nucleotide composition bias and the repeat density of genomes. We hypothesise that in highly biased genomes, non-duplicated small repeats arise more frequently by random effects and are used as primers for duplication mechanisms, leading to a higher density of large repeats.

  11. Magnetotactic bacteria. Promising biosorbents for heavy metals

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Wei; Zhang, Yanzong; Ding, Xiaohui; Liu, Yan; Shen, Fei; Zhang, Xiaohong; Deng, Shihuai; Xiao, Hong; Yang, Gang; Peng, Hong [Sichuan Agricultural Univ., Chengdu (China). Provincial Key Lab. of Agricultural Environmental Engineering

    2012-09-15

    Magnetotactic bacteria (MTB), which can orient and migrate along a magnetic line of force due to intracellular nanosized magnetosomes, have been a subject of research in the medical field, in dating environmental changes, and in environmental remediation. This paper reviews the recent development of MTB as biosorbents for heavy metals. Ultrastructures and taxis of MTB are investigated. Adsorptions in systems of unitary and binary ions are highlighted, as well as adsorption conditions (temperature, pH value, biomass concentration, and pretreatments). The separation and desorption of MTB in magnetic separators are also discussed. A green method to produce metal nanoparticles is provided, and an energy-efficient way to recover precious metals is put forward during biosorption. (orig.)

  12. Magnetotactic bacteria. Magnetic navigation on the microscale

    Science.gov (United States)

    Klumpp, Stefan; Faivre, Damien

    2016-11-01

    Magnetotactic bacteria are aquatic microorganisms with the ability to swim along the field lines of a magnetic field, which in their natural environment is provided by the magnetic field of the Earth. They do so with the help of specialized magnetic organelles called magnetosomes, vesicles containing magnetic crystals. Magnetosomes are aligned along cytoskeletal filaments to give linear structures that can function as intracellular compass needles. The predominant viewpoint is that the cells passively align with an external magnetic field, just like a macroscopic compass needle, but swim actively along the field lines, propelled by their flagella. In this minireview, we give an introduction to this intriguing bacterial behavior and discuss recent advances in understanding it, with a focus on the swimming directionality, which is not only affected by magnetic fields, but also by gradients of the oxygen concentration.

  13. Atypical Bacteria and Macrolides in Asthma

    Directory of Open Access Journals (Sweden)

    Xepapadaki Paraskevi

    2008-09-01

    Full Text Available Chlamydophila pneumoniae and Mycoplasma pneumoniae are common pathogens causing acute illness in both the upper and lower airways. Several observations are supportive of a possible causative role of these pathogens in asthma; however, more evidence is required before this becomes meaningful in clinical practice. Atypical bacteria can enhance airway hyperresponsiveness and inflammation, both of which have been associated with exacerbations in patients with preexisting asthma. It is less clear whether the above mechanisms might also be responsible for the development of asthma. Difficulties in accurately diagnosing these infections contribute to such uncertainty. In the present report, evidence of the involvement of Chlamydophila and Mycoplasma infection in the development and the progression of asthma are reviewed.

  14. Screening Of Marine Bacteria For Pharmacological Activities

    Directory of Open Access Journals (Sweden)

    S. Vijayalakshmi

    2015-08-01

    Full Text Available Abstract The symbiotic and associated four marine bacteria BR1 Flavobacterium sp. isolated from Barnacle Balanus amphitriteEM13 Micrococus sp. from Seaweed Enteromorpha compressaPC4 Alcaligenes sp. from Ascidian Polyclinum constellatum and SW12 Bacillus sp. from seawater were cultured and extracted for pharmacological activities. The ethyl acetate extracts of these marine bacterial culture supernatants were screened for pharmacological activities such as Anti inflammatory Analgesic and CNS depressant activities using experimental animal model. In this studySW12 exhibited high activity for both Anti inflammatory and Analgesic. Especially which exhibited highest analgesic activity than standard drug pethidine. Another one PC4 showed highest analgesic activity similar to standard drug. Other two extracts EM13 and BR1 showed high activity in CNS depressant. Based on the result SW12 is a highly potent strain it may produce novel compound for pharmacological drug.

  15. 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...... to fluoroquinolones, which are used for empirical treatment of diarrhea in humans. Resistance to vancomycin and Synercid((R)) in enterococci is associated with use of similar drugs as growth promoters in food animals. Danish food animal producers have terminated the use of antimicrobial growth promoters. This has...... reduced the total use of antimicrobials by more than 50% and markedly reduced levels of resistance. There is an urgent need to implement globally, WHO principles for prudent use of antimicrobials in food animals. Use of antimicrobials as growth promoters could and should be terminated completely....

  16. Bacteria survival probability in bactericidal filter paper.

    Science.gov (United States)

    Mansur-Azzam, Nura; Hosseinidoust, Zeinab; Woo, Su Gyeong; Vyhnalkova, Renata; Eisenberg, Adi; van de Ven, Theo G M

    2014-05-01

    Bactericidal filter papers offer the simplicity of gravity filtration to simultaneously eradicate microbial contaminants and particulates. We previously detailed the development of biocidal block copolymer micelles that could be immobilized on a filter paper to actively eradicate bacteria. Despite the many advantages offered by this system, its widespread use is hindered by its unknown mechanism of action which can result in non-reproducible outcomes. In this work, we sought to investigate the mechanism by which a certain percentage of Escherichia coli cells survived when passing through the bactericidal filter paper. Through the process of elimination, the possibility that the bacterial survival probability was controlled by the initial bacterial load or the existence of resistant sub-populations of E. coli was dismissed. It was observed that increasing the thickness or the number of layers of the filter significantly decreased bacterial survival probability for the biocidal filter paper but did not affect the efficiency of the blank filter paper (no biocide). The survival probability of bacteria passing through the antibacterial filter paper appeared to depend strongly on the number of collision between each bacterium and the biocide-loaded micelles. It was thus hypothesized that during each collision a certain number of biocide molecules were directly transferred from the hydrophobic core of the micelle to the bacterial lipid bilayer membrane. Therefore, each bacterium must encounter a certain number of collisions to take up enough biocide to kill the cell and cells that do not undergo the threshold number of collisions are expected to survive. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Diversity of bacteria contaminating paper machines.

    Science.gov (United States)

    Lahtinen, Tomi; Kosonen, Mirva; Tiirola, Marja; Vuento, Matti; Oker-Blom, Christian

    2006-09-01

    Formation of microbial biofilms and slimes is a general and serious problem in the operation of paper machines. Studies of microbial populations in paper machine-derived biofilms have been conducted using standard microbiological procedures; however, the bacterial genera present in this type of samples as well as their diversity are quite poorly known. Here, the bacterial diversity of 38 process water and 22 biofilm samples from four different Finnish paper machines were analyzed by length heterogeneity analysis of PCR-amplified 16S ribosomal DNA (LH-PCR). In addition, sequencing of the amplified 16S rRNA gene from 69 clones was conducted for characterization of the bacterial genera present in biofilm and slime samples. The LH-PCR profiles of both the free-living (process waters) and immobilized (biofilms) bacteria were diverse at all stages of the papermaking process. Out of the 69 sequenced clones, 44 belonged to alpha-Proteobacteria, most of which were close to the nitrogen-fixing root nodule genera Sinorhizobium, Rhizobium and Azorhizobium. Other clones were assigned to beta- and gamma-Proteobacteria and the phylum Bacteroidetes. In addition, eight of the clones were assigned to a yet uncultivated phylum, TM7. Finally, epifluorescence microscopy revealed that Gram-negative bacteria were predominant in both the biofilm (65%) and process water (54%) samples and a small coccoid cell morphology was most common in all samples. Together, our results show that the analysis of microbial samples from paper machines using modern molecular biology techniques adds valuable information and should, therefore, be useful as a more specific and sensitive microbiological method for the paper industry. This information could further be applied, e.g., in the development of more specific and environmental friendly antimicrobial agents for paper mills.

  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; Kok, Jan

    2016-09-01

    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.

  19. Fewer Bacteria Adhere to Softer Hydrogels

    Science.gov (United States)

    Kolewe, Kristopher W.; Peyton, Shelly R.; Schiffman, Jessica D.

    2015-01-01

    Clinically, biofilm-associated infections commonly form on intravascular catheters and other hydrogel surfaces. The overuse of antibiotics to treat these infections has led to the spread of antibiotic resistance and underscores the importance of developing alternative strategies that delay the onset of biofilm formation. Previously, it has been reported that during surface contact, bacteria can detect surfaces through subtle changes in the function of their motors. However, how the stiffness of a polymer hydrogel influences the initial attachment of bacteria is unknown. Systematically, we investigated poly(ethylene glycol) dimethacrylate (PEGDMA) and agar hydrogels that were twenty times thicker than the cumulative size of bacterial cell appendages, as a function of Young’s moduli. Soft (44.05 – 308.5 kPa), intermediate (1495 – 2877 kPa), and stiff (5152 – 6489 kPa) hydrogels were synthesized. Escherichia coli and Staphylococcus aureus attachment onto the hydrogels was analyzed using confocal microscopy after 2 and 24 hr incubation periods. Independent of hydrogel chemistry and incubation time, E. coli and S. aureus attachment correlated positively to increasing hydrogel stiffness. For example, after a 24 hr incubation period, there were 52% and 82% less E. coli adhered to soft PEGDMA hydrogels, than to the intermediate and stiff PEGDMA hydrogels, respectively. A 62% and 79% reduction in the area coverage by the Gram-positive microbe S. aureus occurred after 24 hr incubation on the soft versus intermediate and stiff PEGDMA hydrogels. We suggest that hydrogel stiffness is an easily tunable variable that, potentially, could be used synergistically with traditional antimicrobial strategies to reduce early bacterial adhesion, and therefore the occurrence of biofilm-associated infections. PMID:26291308

  20. Abundant oligonucleotides common to most bacteria.

    Directory of Open Access Journals (Sweden)

    Colin F Davenport

    Full Text Available BACKGROUND: Bacteria show a bias in their genomic oligonucleotide composition far beyond that dictated by G+C content. Patterns of over- and underrepresented oligonucleotides carry a phylogenetic signal and are thus diagnostic for individual species. Patterns of short oligomers have been investigated by multiple groups in large numbers of bacteria genomes. However, global distributions of the most highly overrepresented mid-sized oligomers have not been assessed across all prokaryotes to date. We surveyed overrepresented mid-length oligomers across all prokaryotes and normalised for base composition and embedded oligomers using zero and second order Markov models. PRINCIPAL FINDINGS: Here we report a presumably ancient set of oligomers conserved and overrepresented in nearly all branches of prokaryotic life, including Archaea. These oligomers are either adenine rich homopurines with one to three guanine nucleosides, or homopyridimines with one to four cytosine nucleosides. They do not show a consistent preference for coding or non-coding regions or aggregate in any coding frame, implying a role in DNA structure and as polypeptide binding sites. Structural parameters indicate these oligonucleotides to be an extreme and rigid form of B-DNA prone to forming triple stranded helices under common physiological conditions. Moreover, the narrow minor grooves of these structures are recognised by DNA binding and nucleoid associated proteins such as HU. CONCLUSION: Homopurine and homopyrimidine oligomers exhibit distinct and unusual structural features and are present at high copy number in nearly all prokaryotic lineages. This fact suggests a non-neutral role of these oligonucleotides for bacterial genome organization that has been maintained throughout evolution.

  1. Fewer Bacteria Adhere to Softer Hydrogels.

    Science.gov (United States)

    Kolewe, Kristopher W; Peyton, Shelly R; Schiffman, Jessica D

    2015-09-01

    Clinically, biofilm-associated infections commonly form on intravascular catheters and other hydrogel surfaces. The overuse of antibiotics to treat these infections has led to the spread of antibiotic resistance and underscores the importance of developing alternative strategies that delay the onset of biofilm formation. Previously, it has been reported that during surface contact, bacteria can detect surfaces through subtle changes in the function of their motors. However, how the stiffness of a polymer hydrogel influences the initial attachment of bacteria is unknown. Systematically, we investigated poly(ethylene glycol) dimethacrylate (PEGDMA) and agar hydrogels that were 20 times thicker than the cumulative size of bacterial cell appendages, as a function of Young's moduli. Soft (44.05-308.5 kPa), intermediate (1495-2877 kPa), and stiff (5152-6489 kPa) hydrogels were synthesized. Escherichia coli and Staphylococcus aureus attachment onto the hydrogels was analyzed using confocal microscopy after 2 and 24 h incubation periods. Independent of hydrogel chemistry and incubation time, E. coli and S. aureus attachment correlated positively to increasing hydrogel stiffness. For example, after a 24 h incubation period, there were 52 and 82% fewer E. coli adhered to soft PEGDMA hydrogels than to the intermediate and stiff PEGDMA hydrogels, respectively. A 62 and 79% reduction in the area coverage by the Gram-positive microbe S. aureus occurred after 24 h incubation on the soft versus intermediate and stiff PEGDMA hydrogels. We suggest that hydrogel stiffness is an easily tunable variable that could potentially be used synergistically with traditional antimicrobial strategies to reduce early bacterial adhesion and therefore the occurrence of biofilm-associated infections.

  2. Diversity of rumen bacteria in canadian cervids.

    Science.gov (United States)

    Gruninger, Robert J; Sensen, Christoph W; McAllister, Timothy A; Forster, Robert J

    2014-01-01

    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 rumen and

  3. 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

  4. 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)

  5. 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.

  6. Taxonomy of phototrophic green and purple bacteria: a review.

    Science.gov (United States)

    Pfennig, N; Trüper, H G

    1983-01-01

    The presently existing classification for the green and purple bacteria comprises physiological-ecological assemblages of phototrophic bacteria with anoxygenic photosynthesis. The taxonomic units of the different levels were based entirely on common phenotypic traits, including morphological, cytological, physiological and biochemical characteristics. Since degrees of resemblance form the basis of the grouping, this classification cannot reflect the genetic or evolutionary relatedness of these bacteria, neither among themselves nor with other bacteria. The advantage of the artificial system, however, is the use of features which can be established in most laboratories and which allow the comparison and identification of newly isolated strains with those already studied and described. The four existing families correspond to the four major recognized, ecophysiological groups, the Chlorobiaceae and Chloroflexaceae among the green bacteria, and the Chromatiaceae and Rhodospirillaceae among the purple bacteria. Our knowledge of all these groups is incomplete; this is reflected by the fact that seven new species have been described during the past three years (6th Newsletter on phot. bacteria, Trüper and Hansen, 1982). The description of the new genus and species Erythrobacter longus (Shiba and Simidu, 1982) is also interesting, as it comprises aerobic chemoorganotrophic marine bacteria which form bacteriochlorophyll a and carotenoids; however, no strains were able to grow phototrophilcally. Significant success is currently being obtained in the different approaches toward elucidating the genetic relationships within and outside of the purple and green bacteria. Detailed studies of the lipopolysaccharides of several species and genera of the Rhodospirillaceae (Weckesser et al., 1979, and more recent paper) have proven to be very useful for the recognition of relationships or dissimilarities between the species of a genus or between different genera. Amino acid sequence

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. Cholesterol lipids and cholesterol-containing lipid rafts in bacteria.

    Science.gov (United States)

    Huang, Zhen; London, Erwin

    2016-09-01

    Sterols are important components of eukaryotic membranes, but rare in bacteria. Some bacteria obtain sterols from their host or environment. In some cases, these sterols form membrane domains analogous the lipid rafts proposed to exist in eukaryotic membranes. This review describes the properties and roles of sterols in Borrelia and Helicobacter.

  12. Interaction forces between waterborne bacteria and activated carbon particles

    NARCIS (Netherlands)

    Busscher, Henk J.; Dijkstra, Rene J. B.; Langworthy, Don E.; Collias, Dimitris I.; Bjorkquist, David W.; Mitchell, Michael D.; Van der Mei, Henny C.

    2008-01-01

    Activated carbons remove waterborne bacteria from potable water systems through attractive Lifshitz-van der Waals forces despite electrostatic repulsion between negatively charged cells and carbon surfaces. In this paper we quantify the interaction forces between bacteria with negatively and positiv

  13. Flow cytometric assessment of viability of lactic acid bacteria

    NARCIS (Netherlands)

    Bunthof, C.J.; Bloemen, K.; Breeuwer, P.; Rombouts, F.M.; Abee, T.

    2001-01-01

    The viability of lactic acid bacteria is crucial for their applications as dairy starters and as probiotics. We investigated the usefulness of flow cytometry (FCM) for viability assessment of lactic acid bacteria. The esterase substrate carboxyfluorescein diacetate (cFDA) and the dye exclusion DNA b

  14. Linkage between copepods and bacteria in the North Atlantic Ocean

    NARCIS (Netherlands)

    De Corte, D.; Lekunberri, I.; Sintes, E.; Garcia, J.A.L.; Gonzalez, S.; Herndl, G.J.

    2014-01-01

    Copepods and bacteria are fundamental components of the pelagic food web andplay a major role in biogeochemical cycles. Marine bacteria have a free-living or particleattachedlifestyle, but as members of the microbial food web, the only biotic interaction of bacteriais commonly assumed to be with

  15. Compatible solutes in lactic acid bacteria subjected to water stress.

    NARCIS (Netherlands)

    Kets, E.P.W.

    1997-01-01

    The goal of the research project described in this thesis was to investigate the protective effect of compatible solutes on tactic acid bacteria subjected to drying. Dried preparations of lactic acid bacteria are applied as starter cultures in feed and food industries. Dried starter cultures compare

  16. Bacteriocins of lactic acid bacteria : extending the family

    NARCIS (Netherlands)

    Alvarez-Sieiro, Patricia; Montalbán-López, Manuel; Mu, Dongdong; Kuipers, Oscar P

    2016-01-01

    Lactic acid bacteria (LAB) constitute a heterogeneous group of microorganisms that produce lactic acid as the major product during the fermentation process. LAB are Gram-positive bacteria with great biotechnological potential in the food industry. They can produce bacteriocins, which are proteinaceo

  17. Heme and menaquinone induced electron transport in lactic acid bacteria

    NARCIS (Netherlands)

    Brooijmans, R.J.W.; Smit, B.; Santos, dos F.; Riel, van J.; Vos, de W.M.; Hugenholtz, J.

    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. RES

  18. Method of separating bacteria from free living amoebae

    Energy Technology Data Exchange (ETDEWEB)

    Tyndall, Richard L. (Clinton, TN)

    1994-01-01

    New protozoan derived microbial consortia and method for their isolation are provided. Consortia and bacteria isolated therefrom are useful for treating wastes such as trichloroethylene and trinitrotoluene. Consortia, bacteria isolated therefrom, and dispersants isolated therefrom are useful for dispersing hydrocarbons such as oil, creosote, wax, and grease.

  19. Diversity and antibiotic resistance of uropathogenic bacteria from Abidjan

    Directory of Open Access Journals (Sweden)

    J.-L.A. Moroh

    2014-03-01

    Conclusions: The diversity of uropathogenic bacteria obtained appeared to be a characteristic of sub-Saharan African countries. Their resistances to different antibiotics were following a dramatic trend. Waiting to be confronted with therapeutic dead end with the advent of multi-resistant bacteria, identifying the region-specific causes is crucial to adapt antibiotic therapy.

  20. Stalking Antibiotic-Resistant Bacteria in Common Vegetables

    Science.gov (United States)

    Brock, David; Boeke, Caroline; Josowitz, Rebecca; Loya, Katherine

    2004-01-01

    The study developed a simple experimental protocol for studying antibiotic resistant bacteria that will allow students to determine the proportion of such bacteria found on common fruit and vegetable crops. This protocol can open up the world of environmental science and show how human behavior can dramatically alter ecosystems.

  1. 9th International Symposium on Lactic Acid Bacteria

    NARCIS (Netherlands)

    Kuipers, Oscar P.; Poolman, Berend; Hugenholtz, Jeroen

    2008-01-01

    What’s new in the field of lactic acid bacteria? The 9th International Symposium on Lactic Acid Bacteria (LAB9) will take place 31 August to 4 September 2008 in Egmond aan Zee, The Netherlands. Traditionally, the triannual LAB symposium focuses on the themes of genetics, physiology, and applications

  2. Toward more selective bacteria; Vers des bacteries plus selectives

    Energy Technology Data Exchange (ETDEWEB)

    Larane, A.

    1997-05-01

    Broadly used in purification plants of residual waters, the bacteria degradation is used now in water treatment plants. New techniques, as fixed cultures or filtration membranes increase, the reactors yield; in waiting for the genetically modified bacteria, able to eliminate a precise pollutant. (N.C.)

  3. Decontamination of airborne bacteria in meat processing plants

    Science.gov (United States)

    Air has been established as a source of bacterial contamination in meat processing facilities. Airborne bacteria may affect product shelf life, and have food safety implications. The effectiveness of reactive oxygen species (ROS) generating AirOcare equipment on the reduction of airborne bacteria in...

  4. Method of separating bacteria from free living amoebae

    Science.gov (United States)

    Tyndall, Richard L.

    1994-01-01

    New protozoan derived microbial consortia and method for their isolation are provided. Consortia and bacteria isolated therefrom are useful for treating wastes such as trichloroethylene and trinitrotoluene. Consortia, bacteria isolated therefrom, and dispersants isolated therefrom are useful for dispersing hydrocarbons such as oil, creosote, wax, and grease.

  5. Population dynamics of bacteria introduced into bentonite amended soil

    NARCIS (Netherlands)

    Heijnen, C.

    1992-01-01

    Bacteria have frequently been introduced into the soil environment, e.g. for increasing crop production or for biological control purposes. Many applications require high numbers of surviving organisms in order to be effective. However, survival of bacteria after introduction into soil is

  6. Population dynamics of bacteria introduced into bentonite amended soil.

    NARCIS (Netherlands)

    Heijnen, C.E.

    1992-01-01

    Bacteria have frequently been introduced into the soil environment, e.g. for increasing crop production or for biological control purposes. Many applications require high numbers of surviving organisms in order to be effective. However, survival of bacteria after introduction into soil is generally

  7. Performance of shcc with bacteria for concrete patch repair

    NARCIS (Netherlands)

    Sierra Beltran, M.G.; Jonkers, H.M.; Schlangen, E.

    2014-01-01

    The overall performance of concrete patch repair systems depends on the durability of and compatibility between the concrete substrate and the repair material. This paper investigates the performance of a new type of SHCC material with embedded bacteria as a repair material. The bacteria are a

  8. 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.

  9. Nitrogen acquisition in Agave tequilana from degradation of endophytic bacteria.

    Science.gov (United States)

    Beltran-Garcia, Miguel J; White, James F; Prado, Fernanda M; Prieto, Katia R; Yamaguchi, Lydia F; Torres, Monica S; Kato, Massuo J; Medeiros, Marisa H G; Di Mascio, Paolo

    2014-11-06

    Plants form symbiotic associations with endophytic bacteria within tissues of leaves, stems, and roots. It is unclear whether or how plants obtain nitrogen from these endophytic bacteria. Here we present evidence showing nitrogen flow from endophytic bacteria to plants in a process that appears to involve oxidative degradation of bacteria. In our experiments we employed Agave tequilana and its seed-transmitted endophyte Bacillus tequilensis to elucidate organic nitrogen transfer from (15)N-labeled bacteria to plants. Bacillus tequilensis cells grown in a minimal medium with (15)NH4Cl as the nitrogen source were watered onto plants growing in sand. We traced incorporation of (15)N into tryptophan, deoxynucleosides and pheophytin derived from chlorophyll a. Probes for hydrogen peroxide show its presence during degradation of bacteria in plant tissues, supporting involvement of reactive oxygen in the degradation process. In another experiment to assess nitrogen absorbed as a result of endophytic colonization of plants we demonstrated that endophytic bacteria potentially transfer more nitrogen to plants and stimulate greater biomass in plants than heat-killed bacteria that do not colonize plants but instead degrade in the soil. Findings presented here support the hypothesis that some plants under nutrient limitation may degrade and obtain nitrogen from endophytic microbes.

  10. Simple and convenient method for culturing anaerobic bacteria.

    OpenAIRE

    Behbehani, M J; Jordan, H. V.; Santoro, D L

    1982-01-01

    A simple and convenient method for culturing anaerobic bacteria is described. Cultures can be grown in commercially available flasks normally used for preparation of sterile external solutions. A special disposable rubber flask closure maintains anaerobic conditions in the flask after autoclaving. Growth of a variety of anaerobic oral bacteria was comparable to that obtained after anaerobic incubation of broth cultures in Brewer Anaerobic Jars.

  11. Lactic Acid Bacteria : embarking on 30 more years of research

    NARCIS (Netherlands)

    Kok, Jan; Johansen, Eric; Kleerebezem, Michiel; Teusink, Bas

    2014-01-01

    The 11th International Symposium on Lactic Acid Bacteria Lactic Acid Bacteria play important roles in the pro- duction of food and feed and are increasingly used as health-promoting probiotics. The incessant scientific interest in these microorganisms by academic research groups as well as by indust

  12. Bacteriocins of lactic acid bacteria : extending the family

    NARCIS (Netherlands)

    Alvarez-Sieiro, Patricia; Montalbán-López, Manuel; Mu, Dongdong; Kuipers, Oscar P

    2016-01-01

    Lactic acid bacteria (LAB) constitute a heterogeneous group of microorganisms that produce lactic acid as the major product during the fermentation process. LAB are Gram-positive bacteria with great biotechnological potential in the food industry. They can produce bacteriocins, which are

  13. IMPACT OF SOIL MANAGEMENT ON COTTON RHIZOSPHERE BACTERIA

    Science.gov (United States)

    Soil dwelling bacteria and fungi are responsible for a number of ecosystem services critical to agriculture. In particular, bacteria living in the rhizosphere (portion of soil directly influenced by plant roots) and arbuscular mycorrhizal fungi have been shown to improve nutrient and water uptake an...

  14. Viable Legionella pneumophila bacteria in natural soil and rainwater puddles

    NARCIS (Netherlands)

    van Heijnsbergen, E.; de Roda Husman, A. M.; Lodder, W. J.; Bouwknegt, M.; Docters van Leeuwen, A. E.; Bruin, J. P.; Euser, S. M.; den Boer, J. W.; Schalk, J. A C

    2014-01-01

    Aims: For the majority of sporadic Legionnaires' disease cases the source of infection remains unknown. Infection may possible result from exposure to Legionella bacteria in sources that are not yet considered in outbreak investigations. Therefore, potential sources of pathogenic Legionella bacteria

  15. Population dynamics of bacteria introduced into bentonite amended soil

    NARCIS (Netherlands)

    Heijnen, C.

    1992-01-01

    Bacteria have frequently been introduced into the soil environment, e.g. for increasing crop production or for biological control purposes. Many applications require high numbers of surviving organisms in order to be effective. However, survival of bacteria after introduction into soil is g

  16. Classification of methanogenic bacteria by 16S ribosomal RNA characterization

    Energy Technology Data Exchange (ETDEWEB)

    Fox, G.E.; Magrum, L.J.; Balch, W.E.; Wolfe, R.S.; Woese, C.R.

    1977-10-01

    The 16S ribosomal RNAs from 10 species of methanogenic bacteria have been characterized in terms of the oligonucleotides produced by T/sub 1/ RNase digestion. Comparative analysis of these data reveals the methanogens to constitute a distinct phylogenetic group containing two major divisions. These organisms appear to be only distantly related to typical bacteria.

  17. Functional genomics of lactic acid bacteria: from food to health

    NARCIS (Netherlands)

    Douillard, F.P.; Vos, de W.M.

    2014-01-01

    Genome analysis using next generation sequencing technologies has revolutionized the characterization of lactic acid bacteria and complete genomes of all major groups are now available. Comparative genomics has provided new insights into the natural and laboratory evolution of lactic acid bacteria a

  18. Linkage between copepods and bacteria in the North Atlantic Ocean

    NARCIS (Netherlands)

    De Corte, D.; Lekunberri, I.; Sintes, E.; Garcia, J.A.L.; Gonzalez, S.; Herndl, G.J.

    2014-01-01

    Copepods and bacteria are fundamental components of the pelagic food web andplay a major role in biogeochemical cycles. Marine bacteria have a free-living or particleattachedlifestyle, but as members of the microbial food web, the only biotic interaction of bacteriais commonly assumed to be with the

  19. Niche differentiation between ammonia-oxidizing bacteria in aquatic environments

    NARCIS (Netherlands)

    Coci, M.

    2007-01-01

    The aim of the studies presented in this thesis was the search for niche differentiation between the ammonia-oxidizing bacteria in aquatic environments. Ammonia-oxidizing bacteria are chemolitho-autotrophic microorganisms responsible for the first, mostly rate-limiting step of the nitrification

  20. Functional genomics of lactic acid bacteria: from food to health

    NARCIS (Netherlands)

    Douillard, F.P.; Vos, de W.M.

    2014-01-01

    Genome analysis using next generation sequencing technologies has revolutionized the characterization of lactic acid bacteria and complete genomes of all major groups are now available. Comparative genomics has provided new insights into the natural and laboratory evolution of lactic acid bacteria