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Sample records for culturable heterotrophic bacteria

  1. Diversity and biosynthetic potential of culturable aerobic heterotrophic bacteria isolated from Magura Cave, Bulgaria

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    Tomova Iva

    2013-01-01

    Full Text Available Biocapacity of bacteria inhabiting karstic caves to produce valuable biologically active compounds is still slightly investigated. A total of 46 culturable heterotrophic bacteria were isolated under aerobic conditions from the Gallery with pre-historical drawings in Magura Cave, Bulgaria. Phylogenetic analysis revealed that most of bacterial isolates aff iliated with Proteobacteria (63%, followed by Actinobacteria (10.9%, Bacteroidetes (10.9%, and Firmicutes (6.5%. A strong domination of Gram-negative bacteria (total 81% belonging to nine genera: Serratia, Pseudomonas, Enterobacter, Sphingobacterium, Stenotrophomonas, Commamonas, Acinetobacter, Obesumbacterium, and Myroides, was observed. Gram-positive isolates were represented by the genera Bacillus, Arthrobacter, and Micrococcus. One isolate showed a signif icant phylogenetic distance to the closest neighbor and could represent а novel species. Heterotrophic bacterial isolates from Magura Cave were investigated for hydrolytic enzymes production, antimicrobial and hemolytic activity. Predominance of producers of protease (87%, followed by xanthan lyase (64%, lipase (40%, β-glycosidase (40%, and phytase (21% was observed. Over 75% of the isolates demonstrated antimicrobial and hemolytic activity. The results suggest that heterotrophic bacteria isolated from Magura Cave could be a valuable source of industrially relevant psychrotolerant enzymes and bioactive metabolites. This study is a f irst report on the taxonomic composition and biological activity of culturable bacteria inhabiting a cave in Bulgaria.

  2. Leaching of pyrite by acidophilic heterotrophic iron-oxidizing bacteria in pure and mixed cultures

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    Bacelar-Nicolau, P.; Johnson, D.B. [Univ. of Wales, Bangor (United Kingdom). School of Biological Sciences

    1999-02-01

    Seven strains of heterotrophic iron-oxidizing acidophilic bacteria were examined to determine their abilities to promote oxidative dissolution of pyrite (FeS{sub 2}) when they were grown in pure cultures and in mixed cultures with sulfur-oxidizing Thiobacillus spp. Only one of the isolates (strain T-24) oxidized pyrite when it was grown in pyrite-basal salts medium. However, when pyrite-containing cultures were supplemented with 0.02% (wt/vol) yeast extract, most of the isolates oxidized pyrite, and one (strain T-24) promoted rates of mineral dissolution similar to the rates observed with the iron-oxidizing autotroph Thiobacillus ferroxidans. Pyrite oxidation by another isolate (strain T-21) occurred in cultures containing between 0.005 and 0.05% (wt/vol) yeast extract but was completely inhibited in cultures containing 0.5% yeast extract. Ferrous iron was also needed for mineral dissolution by the iron-oxidizing heterotrophs, indicating that these organisms oxidize pyrite via the indirect mechanism. Mixed cultures of three isolates (strains T-21, T-232, and T-24) and the sulfur-oxidizing autotroph Thiobacillus thiooxidans promoted pyrite dissolution; since neither strains T-21 and T-23 nor T. thiooxidans could oxidize this mineral in yeast extract-free media, this was a novel example of bacterial synergism. Mixed cultures of strains T-21 and T-23 and the sulfur-oxidizing mixotroph Thiobacillus acidophilus also oxidized pyrite but to a lesser extent than did mixed cultures containing T. thiooxidans. Pyrite leaching by strain T -23 grown in an organic compound-rich medium and incubated either shaken or unshaken was also assessed. The potential environmental significance of iron-oxidizing heterotrophs in accelerating pyrite oxidation is discussed.

  3. Culturable heterotrophic bacteria from the marine sponge Dendrilla nigra: isolation and phylogenetic diversity of actinobacteria

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    Selvin, Joseph; Gandhimathi, R.; Kiran, G. Seghal; Priya, S. Shanmugha; Ravji, T. Rajeetha; Hema, T. A.

    2009-09-01

    Culturable heterotrophic bacterial composition of marine sponge Dendrilla nigra was analysed using different enrichments. Five media compositions including without enrichment (control), enriched with sponge extract, with growth regulator (antibiotics), with autoinducers, and complete enrichment containing sponge extract, antibiotics, and autoinducers were developed. DNA hybridization assay was performed to explore host specific bacteria and ecotypes of culturable sponge-associated bacteria. Enrichment with selective inducers (AHLs and sponge extract) and regulators (antibiotics) considerably enhanced the cultivation potential of sponge-associated bacteria. It was found that Marinobacter (MSI032), Micromonospora (MSI033), Streptomyces (MSI051), and Pseudomonas (MSI057) were sponge-associated obligate symbionts. The present findings envisaged that “ Micromonospora-Saccharomonospora-Streptomyces” group was the major culturable actinobacteria in the marine sponge D. nigra. The DNA hybridization assay was a reliable method for the analysis of culturable bacterial community in marine sponges. Based on the culturable community structure, the sponge-associated bacteria can be grouped (ecotypes) as general symbionts, specific symbionts, habitat flora, and antagonists.

  4. Microbial pollution indicators and culturable heterotrophic bacteria in a Mediterranean area (Southern Adriatic Sea Italian coasts)

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    Stabili, L.; Cavallo, R. A.

    2011-05-01

    In the present study we evaluated the degree of microbial water pollution along the coast line between Brindisi and Santa Maria di Leuca (Southern Adriatic Sea) as well as the culturable heterotrophic bacteria abundances and biodiversity in relation to the microbiological quality of the water. A total of 3773 colonies were isolated, subcultured and identified by several morphological, cultural and biochemical methods including the standardized API 20 E and API 20 NE tests. Along the examined coastal tract the microbial pollution indicators were always below the tolerance limits for bathing waters defined by the CEE directive, suggesting a good sanitary quality. Concerning culturable heterotrophic bacteria, different temporal density trends were observed in the four sites in relation to their geographical position. A positive relationship between the bacterial abundances and the temperature was observed in S. Cataldo and Otranto. The culturable bacterial community was mainly composed of the genera Aeromonas, Pseudomonas, Photobacterium and Flavobacterium. The Enterobacteriaceae family represented a conspicuous component of the bacterial community too. Bacilli were predominant among the Gram-positive bacteria. Of interest is the isolation of yeasts (2% at the surface and 1% at the bottom) taking into account their capability of biodegradation of various materials. Because of the low level of microbial pollution recorded, our results are indicative of the natural variation and diversity of the culturable bacterial community in such an oligotrophic ecosystem and could represent a good point of comparison with other ecosystems as well as a baseline for long term studies aimed to evaluate the effects of environmental fluctuations and human impacts on this aspect of biodiversity in coastal areas.

  5. Diversity and antimicrobial potential of culturable heterotrophic bacteria associated with the endemic marine sponge Arenosclera brasiliensis

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    Cintia P.J. Rua

    2014-06-01

    Full Text Available Marine sponges are the oldest Metazoa, very often presenting a complex microbial consortium. Such is the case of the marine sponge Arenosclera brasiliensis, endemic to Rio de Janeiro State, Brazil. In this investigation we characterized the diversity of some of the culturable heterotrophic bacteria living in association with A. brasiliensis and determined their antimicrobial activity. The genera Endozoicomonas (N = 32, Bacillus (N = 26, Shewanella (N = 17, Pseudovibrio (N = 12, and Ruegeria (N = 8 were dominant among the recovered isolates, corresponding to 97% of all isolates. Approximately one third of the isolates living in association with A. brasiliensis produced antibiotics that inhibited the growth of Bacillus subtilis, suggesting that bacteria associated with this sponge play a role in its health.

  6. Biodiversity of culturable heterotrophic bacteria in the Southern Adriatic Sea Italian coastal waters

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    Loredana Stabili

    2004-04-01

    Full Text Available The qualitative and quantitative composition of culturable heterotrophic bacteria in water samples from the Southern Adriatic Sea of Italy was examined. Water samples were collected monthly, for a year, at 16 stations along the coast line between Brindisi and Santa Maria di Leuca. The results obtained described the heterotrophic bacterial community over an annual cycle. Mean values of bacterial densities were 5.3 x 104 CFUml-1 in Brindisi, 5.8 x 104 CFUml-1 in S. Cataldo, 4.3 x 104 CFUml-1 in Otranto and 6.7 x 104 CFUml-1 in S. M. di Leuca. The differences in bacterial densities between the sites considered were estimated. The hydrodynamic circulation, the trophism and the geographical position of the examined sites contribute to justify the different bacterial density trends. The bacterial community consisted mainly of the genera Aeromonas, Pseudomonas, Photobacterium and Flavobacterium. The Enterobacteriaceae represented a considerable fraction of the bacterial community in the Southern Adriatic Sea. Bacilli were predominant among the Gram positive bacteria. The enzymatic versatility of the observed genera suggest their importance in organic matter turnover of this oligotrophic ecosystem.

  7. Culturable heterotrophic bacteria from Potter Cove, Antarctica, and their hydrolytic enzymes production

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    Mauro Tropeano

    2012-12-01

    Full Text Available Affiliations of the dominant culturable bacteria isolated from Potter Cove, South Shetland Islands, Antarctica, were investigated together with their production of cold-active hydrolytic enzymes. A total of 189 aerobic heterotrophic bacterial isolates were obtained at 4°C and sorted into 63 phylotypes based on their amplified ribosomal DNA restriction analysis profiles. The sequencing of the 16S rRNA genes of representatives from each phylotype showed that the isolates belong to the phyla Proteobacteria (classes Alpha- and Gamma-proteobacteria, Bacteroidetes (class Flavobacteria, Actinobacteria (class Actinobacteria and Firmicutes (class Bacilli. The predominant culturable group in the site studied belongs to the class Gammaproteobacteria, with 65 isolates affiliated to the genus Pseudoalteromonas and 58 to Psychrobacter. Among the 189 isolates screened, producers of amylases (9.5%, pectinases (22.8%, cellulases (14.8%, CM-cellulases (25.4%, xylanases (20.1% and proteases (44.4% were detected. More than 25% of the isolates produced at least one extracellular enzyme, with some of them producing up to six of the tested extracellular enzymatic activities. These results suggest that a high culturable bacterial diversity is present in Potter Cove and that this place represents a promising source of biomolecules.

  8. Culturable heterotrophic bacteria from the euphotic zone of the Indian Ocean ocean during the summer monsoon

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    Nair, S.; LokaBharathi, P.A.; Chandramohan, D.

    Cuturable heterotrophic bacterial counts (viable counts: VC) by surface plating on ZoBell medium and total bacterial counts (TC) by epifuorenscence microscopy were carried out in sea water off the southwest coast of India during the monsoon. TC were...

  9. Self-sustaining, solar-driven bioelectricity generation in micro-sized microbial fuel cell using co-culture of heterotrophic and photosynthetic bacteria

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    Liu, Lin; Choi, Seokheun

    2017-04-01

    Among many energy harvesting techniques with great potential, microbial fuel cell (MFC) technology is arguably the most underdeveloped. Even so, excitement is building, as microorganisms can harvest electrical power from any biodegradable organic source (e.g. wastewater) that is readily available in resource-limited settings. Nevertheless, the requirement for endless introduction of organic matter imposes a limiting factor to this technology, demanding an active feeding system and additional power. Here, we demonstrated self-sustaining bioelectricity generation from a microliter-scale microbial fuel cell (MFC) by using the syntrophic interaction between heterotrophic exoelectrogenic bacteria and phototrophs. The MFC continuously generated light-responsive electricity from the heterotrophic bacterial metabolic respiration with the organic substrates produced by photosynthetic bacteria. Without additional organic fuel, the mixed culture in a 90-μL-chamber MFC generated self-sustained current for more than 13 days, while the heterotrophic culture produced current that decreased dramatically within a few hours. The current from the mixed culture was about 70 times greater than that of the device with only photosynthetic bacteria. The miniaturization provided a short start-up time, a well-controlled environment, and small internal resistance. Those advantages will become the general design platform for micropower generation.

  10. Light scattering by marine heterotrophic bacteria

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    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.

  11. Viruses, bacteria, and heterotrophic nanoflagellates in Laptev Sea plankton

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    Kopylov, A. I.; Sazhin, A. F.; Zabotkina, E. A.; Romanenko, A. V.; Romanova, N. D.; Makarevich, P. R.; Wenger, M. P.

    2016-11-01

    The paper considers the concentrations and functional characteristics of viruses, bacteria, and heterotrophic nanoflagellates determined for the first time in the Laptev Sea in August-September, 2014. The abundance of bacteria, viruses, and heterotrophic nanoflagellates varied from 110.1 × 103 to 828.4 × 103 cells/mL, from 384.2 × 103 to 2932.8 × 103 particles/mL, and from 108 to 651 cells/mL, respectively. The daily bacterioplankton production varied from 4.2 × 103 to 381.7 × 103 cells/mL, with an average of 117.6 × 103 cells/mL. Electron transmission microscopy has for the first time shown that the frequency of visibly infected bacterial cells varied from 0.2 to 2.0% (0.8% on average) of NB. The average virus-induced mortality of bacteria was 6.3% of bacterioplankton production, with variations ranging from 1.4 to 16.9%. Grazing on bacteria by heterotrophic nanoflagellates contributed more to bacteria mortality than virus-induced bacterial lysis. By grazing on bacteria, heterotrophic nanoflagellates consumed large quantities of viruses located on the surface and inside bacterial cells.

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

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    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.

  13. Abundance and Biomass of Benthic Heterotrophic Bacteria in Jiaozhou Bay, China

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The abundance and biomass of benthic heterotrophic bacteria were investigated for the 4 typical sampling stations in the northern muddy part of Jiaozhou Bay, estuary of the Dagu River, raft culturing and nearby areas of Huangdao in March, June, August and December, 2002. The abundance and biomass range from 0 . 98×107 to 16 . 87×107cells g - 1 sediment and 0 . 45 to 7 . 08 μg C g - 1 sediment, respectively. Correlation analysis showed that heterotrophic bacterial abundance and biomass are significantly correlated to water temperature (R=0 . 79 and 0 . 83, respectively, P<0 . 01).

  14. 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.

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

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    Churilin, Nikita; Soina, Vera

    2015-04-01

    The study of diversity and functional state of microorganisms in subsurface rocks layers, their participation in the biochemical weathering and formation of organic horizons of soils is important for understanding ecology and microorganisms in Antarctic soils. The study of cultured forms of microorganisms and their potential viability is still relevant to characterize the physiological state, biological activity and resilience of microorganisms involved in the initial soil formation. Improvement of isolation techniques of viable bacteria from the extreme habitats has a particular importance for rising the efficiency of environmental monitoring. The aim of the study was to investigate the viable heterotrophic bacteria involved in the formation of soils from wet valleys Larsemann Oasis, which is one of the warmest ice-free space of East Antarctica. Soil samples were taken from the intermountain humid valleys, where silt-gravelly substrates formed moss, algae, lichen cover. We used nutrient solutions (trypticase soy, R2A and glucose-peptone) to isolate cultured bacteria and study their morphological types in the light microscope. The total number of microorganisms was determined by fluorescent microscopy with acridine orange. SEM was used for morphological studies of bacterial communities in situ. To activate the growth processes we added into nutrient solutions various regulatory metabolites that have dose-dependence and operate at the community level. Physiological and functional conditions were determined by the duration of the lag phase and specific growth rate of bacterial communities in nutrient solutions containing various organic substrates. Soils form under protection of «stone pavement» and organisms leave the surface, so the forming organo-mineral horizon occurs inside of rock, thus the microprofile can form on both sides of the organic horizons. UV radiation, lack of moisture and strong wind are main limiting factors for microorganisms' growth in

  16. Interactions of Methylotrophs with Plants and Other Heterotrophic Bacteria

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    Hiroyuki Iguchi

    2015-04-01

    Full Text Available Methylotrophs, which can utilize methane and/or methanol as sole carbon and energy sources, are key players in the carbon cycle between methane and CO2, the two most important greenhouse gases. This review describes the relationships between methylotrophs and plants, and between methanotrophs (methane-utilizers, a subset of methylotrophs and heterotrophic bacteria. Some plants emit methane and methanol from their leaves, and provide methylotrophs with habitats. Methanol-utilizing methylotrophs in the genus Methylobacterium are abundant in the phyllosphere and have the ability to promote the growth of some plants. Methanotrophs also inhabit the phyllosphere, and methanotrophs with high methane oxidation activities have been found on aquatic plants. Both plant and environmental factors are involved in shaping the methylotroph community on plants. Methanotrophic activity can be enhanced by heterotrophic bacteria that provide growth factors (e.g., cobalamin. Information regarding the biological interaction of methylotrophs with other organisms will facilitate a better understanding of the carbon cycle that is driven by methylotrophs.

  17. Culturing bias in marine heterotrophic flagellates analyzed through seawater enrichment incubations.

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    del Campo, Javier; Balagué, Vanessa; Forn, Irene; Lekunberri, Itziar; Massana, Ramon

    2013-10-01

    The diversity of heterotrophic flagellates is generally based on cultivated strains, on which ultrastructural, physiological, and molecular studies have been performed. However, the relevance of these cultured strains as models of the dominant heterotrophic flagellates in the marine planktonic environment is unclear. In fact, molecular surveys typically recover novel eukaryotic lineages that have refused cultivation so far. This study was designed to directly address the culturing bias in planktonic marine heterotrophic flagellates. Several microcosms were established adding increasing amounts and sources of organic matter to a confined natural microbial community pre-filtered by 3 μm. Growth dynamics were followed by epifluorescence microscopy and showed the expected higher yield of bacteria and heterotrophic flagellates at increased organic matter additions. Moreover, protist diversity analyzed by molecular tools showed a clear substitution in the community, which differed more and more from the initial sample as the organic matter increased. Within this gradient, there was also an increase of sequences related to cultured organisms as well as a decrease in diversity. Culturing bias is partly explained by the use of organic matter in the isolation process, which drives a shift in the community to conditions closer to laboratory cultures. An intensive culturing effort using alternative isolation methods is necessary to allow the access to the missing heterotrophic flagellates that constitute the abundant and active taxa in marine systems.

  18. Modeling of heterotrophic bacteria counts in a water distribution system.

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    Francisque, Alex; Rodriguez, Manuel J; Miranda-Moreno, Luis F; Sadiq, Rehan; Proulx, François

    2009-03-01

    Heterotrophic plate count (HPC) constitutes a common indicator for monitoring of microbiological water quality in distribution systems (DS). This paper aims to identify factors explaining the spatiotemporal distribution of heterotrophic bacteria and model their occurrence in the distribution system. The case under study is the DS of Quebec City, Canada. The study is based on a robust database resulting from a sampling campaign carried out in about 50 DS locations, monitored bi-weekly over a three-year period. Models for explaining and predicting HPC levels were based on both one-level and multi-level Poisson regression techniques. The latter take into account the nested structure of data, the possible spatiotemporal correlation among HPC observations and the fact that sampling points, months and/or distribution sub-systems may represent clusters. Models show that the best predictors for spatiotemporal occurrence of HPC in the DS are: free residual chlorine that has an inverse relation with the HPC levels, water temperature and water ultraviolet absorbance, both having a positive impact on HPC levels. A sensitivity analysis based on the best performing model (two-level model) allowed for the identification of seasonal-based strategies to reduce HPC levels.

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

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    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.

  20. Polyhydroxyalkanoate production potential of heterotrophic bacteria in activated sludge.

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    Inoue, Daisuke; Suzuki, Yuta; Uchida, Takahiro; Morohoshi, Jota; Sei, Kazunari

    2016-01-01

    This study was conducted to evaluate the polyhydroxyalkanoate (PHA) production potential of cultivable heterotrophic bacteria in activated sludge by genotypic and phenotypic characterizations. A total of 114 bacterial strains were isolated from four activated sludge samples taken from a lab-scale sequencing batch reactor and three wastewater treatment processes of two municipal wastewater treatment plants. PCR detection of the phaC genes encoding class I and II PHA synthase revealed that 15% of the total isolates possessed phaC genes, all of which had the closest similarities to known phaC genes of α- and β-Proteobacteria and Actinobacteria. PHA production experiments under aerobic and nitrogen-limited conditions showed that 68% of the total isolates were capable of producing PHA from at least one of the six substrates used (acetate, propionate, lactate, butyrate, glucose and glycerol). Genotypic and phenotypic characterizations revealed that 75% of the activated sludge bacteria had PHA production potential. Our results also indicated that short-chain fatty acids would be the preferable substrates for PHA production by activated sludge bacteria, and that there might be a variety of unidentified phaC genes in activated sludge.

  1. Isolation and Characteristics of New Heterotrophic Nitrifying Bacteria

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    SU Jun-feng; MA Fang; WANG Hong-yu; GUO Jing-bo; HOU Ning; LI Wei-guo; WEI Li

    2007-01-01

    The study presented the method for isolating the heterotrophic nitrifiers and the characterization of heterotrophic nitrification. When influent Ammonia nitrogen concentration was 42. 78-73. 62 mg/L. The average ammonia nitrogen removal rate was 81,32% from the bio-ceramics reactor. Sodium acetate and ammonium chloride were used as carbon and nitrogen source. The COD removal rates by microorganisms of strain wgy21 and wgy36 were 56.1% and 45.45%, respectively. The TN removal rates by microorganisms of strain wgy21 and wgy36 were 65.85%and 67. 98%, respectively. At the same time, the concentration of ammonium nitrogen was with the removal rates of 75.25% and 84.96%, and it also had the function of producing NO2-N. Sodium acetate and sodium nitrite were used as carbon and nitrogen source. Through the 12days of the aerobic culture, the COD femoral rates by microorganisms of strain wgy21 and wgy36 were 29.25%and 22.08%, respectively. NO2-N concentration decreased slowly. Comparison, similarity of wgy21 and many Acinetobacter sp. ≥99%, similarity of wgy36 and many Acinetobacter sp. ≥99%. Refer to routine physiological-biochemical characteristic determination, further evidences showed that wgy21 and wgy36 belong to Acinetobacter sp.,respectively.

  2. Survey on Heterotrophic Bacterial Contamination in Bottled Mineral Water by Culture Method

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    Essmaeel Ghorbanalinezhad

    2014-12-01

    Full Text Available Background and Aim: This project focuses on the level of heterotrophic baceria in bottled mineral water which could be a health concern for the elderly, infants, pregnant women and immuno-compromised patients. Materials and Methods: Different brands of bottled water samples were selected randomly and evaluated for their bacteriological quality, using different specific culture media and biochemical tests. Water samples were analyzed within 24 hours of their purchase/collection. Samples were filtered with 0.45 micron and filters were plated in different media. Then media were incubated at 37˚C for 24-48 hours. Results: Morphological study and biochemical tests revealed a number of bacteria in different   brands of  bottled water. Heterotrophic bacteria(Gram positive cocci, Spore forming gram positive bacilli, non spore forming gram positive bacilli, gram negative bacilli, and gram negative coccobacilli; Pseudomonas and Stenotrophomonas counted in 70% of bottled water samples. There were no cases of fecal contamination or the presence of E.coli. Conclusions: Bottled water is not sterile and contains trace amounts of bacteria naturally present or introduced during processing. Testing drinking water for all possible pathogens is complex, time-consuming, and expensive. If only total coliform bacteria are detected in drinking water, the source is probably environmental. Since the significance of non-pathogenic heterotrophic bacteria in relation to health and diseases is not understood, there is an urgent need to establish a maximum limit for the heterotrophic count in the bottled mineral water. Growth conditions play a critical role in the recovery of heterotrophic bacteria in bottled drinking water.

  3. Sulfate-reducing bacteria from the Arabian Sea - their distribution in relation to thiosulfate-oxidising and heterotrophic bacteria

    Digital Repository Service at National Institute of Oceanography (India)

    LokaBharathi, P.A.; Chandramohan, D.

    and Tables 1-3. Water samples were collected using sterile JZ samplers. Sediment samples were collected using a Petersen's grab. Chemical and bacteriological analyses of the samples were carried out on board immediatelyaftercollection. Salinity, oxygen... in sterile sea water blanks before inoculation. Media and Technique. -Culturable aerobic heterotrophic bacteria (AB) were enumerated on nutrient agar (peptone, 5 g; beef extract, 1.5 g; yeast extract, I.S g; agar, 8 g; at pH 7.8) prepared in sea water (35%o...

  4. BACTERIOLOGICAL PROPERTIES OF MARINE WATER IN ADRIATIC FISH FARMS: ENUMERATION OF HETEROTROPHIC BACTERIA

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    Emin Teskeredžić

    2012-12-01

    Full Text Available Aquaculture is currently one of the fastest growing food production sectors in the world. Increase in nutrients and organic wastes lead to general deterioration of water quality. The problem of water quality is associated with both physical and chemical factors, as well as microbiological water quality. Heterotrophic bacteria play an important role in the process of decomposition of organic matter in water environment and indicate eutrophication process. Here we present our experience and knowledge on bacterial properties of marine water in the Adriatic fish farms with European sea bass (Dicentrarchus labrax L., 1758, with an emphasis on enumeration of heterotrophic bacteria in marine water. We applied two temperatures of incubation, as well as two methods for enumeration of heterotrophic bacteria: substrate SimPlate® test and spread plate method on conventional artificial media (Marine agar and Tryptic Soy agar with added NaCl. The results of analysis of bacteriological properties of marine water in the Adriatic fish farms showed that enumeration of heterotrophic bacteria in marine water depends on the applied incubation temperature and media for enumeration. At the same time, the incubation temperature of 22C favours more intense growth of marine heterotrophic bacteria, whereas a SimPlate test gives higher values of heterotrophic bacteria. Volatile values of heterotrophic bacteria during this research indicate a possible deterioration of microbiological water quality in the Adriatic fish farms and a need for regular monitoring of marine water quality.

  5. The antimicrobial activity of heterotrophic bacteria isolated from the marine sponge Erylus deficiens (Astrophorida, Geodiidae

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    Ana Patrícia Graça

    2015-05-01

    Full Text Available Interest in the study of marine sponges and their associated microbiome has increased both for ecological reasons and for their great biotechnological potential. In this work, heterotrophic bacteria associated with three specimens of the marine sponge Erylus deficiens, were isolated in pure culture, phylogenetically identified and screened for antimicrobial activity. The isolation of bacteria after an enrichment treatment in heterotrophic medium revealed diversity in bacterial composition with only Pseudoalteromonas being shared by two specimens. Of the 83 selected isolates, 58% belong to Proteobacteria, 23 % to Actinobacteria and 19 % to Firmicutes. Diffusion agar assays for bioactivity screening against four bacterial strains and one yeast, revealed that a high number of the isolated bacteria (68.7 % were active, particularly against Candida albicans and Vibrio anguillarum. Pseudoalteromonas, Microbacterium and Proteus were the most bioactive genera. After this preliminary screening, the bioactive strains were further evaluated in liquid assays against C. albicans, Bacillus subtilis and Escherichia coli. Filtered culture medium and acetone extracts from three and five days-old cultures were assayed. High antifungal activity against C. albicans in both aqueous and acetone extracts as well as absence of activity against B. subtilis were confirmed. Higher levels of activity were obtained with the aqueous extracts when compared to the acetone extracts and differences were also observed between the 3 and 5 day-old extracts. Furthermore, a low number of active strains was observed against E. coli. Potential presence of type-I polyketide synthases (PKS-I and nonribosomal peptide synthetases (NRPSs genes were detected in seventeen and thirty isolates, respectively. The high levels of bioactivity and the likely presence of associated genes suggest that Erylus deficiens bacteria are potential sources of novel marine bioactive compounds.

  6. Unicellular cyanobacteria synechocystis accommodate heterotrophic bacteria with varied enzymatic and metal resistance properties

    Digital Repository Service at National Institute of Oceanography (India)

    Anas, A.; Sageer, S.; Jasmin, C.; Vijayan, V.; Pavanan, P.; Athiyanathil, S.; Nair, S.

    unicellular cyanobacterium Synechocystis sp. that came from a heavy metal contaminated region of Cochin estuary, southwest coast of India. Based on 16S rRNA gene sequence similarities, the heterotrophic bacteria were grouped into three phyla: namely...

  7. HETEROTROPHIC PLATE COUNT BACTERIA - WHAT IS THEIR SIGNIFICANCE IN DRINKING WATER?

    Science.gov (United States)

    The possible health significance of heterotrophic plate count (HPC) bacteria, also know in earlier terminology as standard plate count (SPC) bacteria, in drinking water has been debated for decades. While the literature documents the universal occurrence of HPC bacteria in soil, ...

  8. Molasses as C source for heterotrophic bacteria production on solid fish waste

    NARCIS (Netherlands)

    Schneider, O.; Sereti, V.; Eding, E.H.; Verreth, J.A.J.

    2006-01-01

    The drumfilter effluent from a recirculation aquaculture system (RAS) can be used as substrate for heterotrophic bacteria production. These bacteria can be reused as aquatic feed. In RAS drumfilter effluents are organic carbon deficient for bacteria production. This is due to nitrogen accumulation i

  9. The dynamics of heterotrophic algal cultures.

    Science.gov (United States)

    De la Hoz Siegler, H; Ben-Zvi, A; Burrell, R E; McCaffrey, W C

    2011-05-01

    In this work, the time varying characteristics of microalgal cultures are investigated. Microalgae are a promising source of biofuels and other valuable chemicals; a better understanding of their dynamic behavior is, however, required to facilitate process scale-up, optimization and control. Growth and oil production rates are evaluated as a function of carbon and nitrogen sources concentration. It is found that nitrogen has a major role in controlling the productivity of microalgae. Moreover, it is shown that there exists a nitrogen source concentration at which biomass and oil production can be maximized. A mathematical model that describes the effect of nitrogen and carbon source on growth and oil production is proposed. The model considers the uncoupling between nutrient uptake and growth, a characteristic of algal cells. Validity of the proposed model is tested on fed-batch cultures. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. Nutrient and media recycling in heterotrophic microalgae cultures.

    Science.gov (United States)

    Lowrey, Joshua; Armenta, Roberto E; Brooks, Marianne S

    2016-02-01

    In order for microalgae-based processes to reach commercial production for biofuels and high-value products such as omega-3 fatty acids, it is necessary that economic feasibility be demonstrated at the industrial scale. Therefore, process optimization is critical to ensure that the maximum yield can be achieved from the most efficient use of resources. This is particularly true for processes involving heterotrophic microalgae, which have not been studied as extensively as phototrophic microalgae. An area that has received significant conceptual praise, but little experimental validation, is that of nutrient recycling, where the waste materials from prior cultures and post-lipid extraction are reused for secondary fermentations. While the concept is very simple and could result in significant economic and environmental benefits, there are some underlying challenges that must be overcome before adoption of nutrient recycling is viable at commercial scale. Even more, adapting nutrient recycling for optimized heterotrophic cultures presents some added challenges that must be identified and addressed that have been largely unexplored to date. These challenges center on carbon and nitrogen recycling and the implications of using waste materials in conjunction with virgin nutrients for secondary cultures. The aim of this review is to provide a foundation for further understanding of nutrient recycling for microalgae cultivation. As such, we outline the current state of technology and practical challenges associated with nutrient recycling for heterotrophic microalgae on an industrial scale and give recommendations for future work.

  11. Deep Subsurface Life from North Pond: Enrichment, Isolation, Characterization and Genomes of Heterotrophic Bacteria.

    Science.gov (United States)

    Russell, Joseph A; León-Zayas, Rosa; Wrighton, Kelly; Biddle, Jennifer F

    2016-01-01

    Studies of subsurface microorganisms have yielded few environmentally relevant isolates for laboratory studies. In order to address this lack of cultivated microorganisms, we initiated several enrichments on sediment and underlying basalt samples from North Pond, a sediment basin ringed by basalt outcrops underlying an oligotrophic water-column west of the Mid-Atlantic Ridge at 22°N. In contrast to anoxic enrichments, growth was observed in aerobic, heterotrophic enrichments from sediment of IODP Hole U1382B at 4 and 68 m below seafloor (mbsf). These sediment depths, respectively, correspond to the fringes of oxygen penetration from overlying seawater in the top of the sediment column and upward migration of oxygen from oxic seawater from the basalt aquifer below the sediment. Here we report the enrichment, isolation, initial characterization and genomes of three isolated aerobic heterotrophs from North Pond sediments; an Arthrobacter species from 4 mbsf, and Paracoccus and Pseudomonas species from 68 mbsf. These cultivated bacteria are represented in the amplicon 16S rRNA gene libraries created from whole sediments, albeit at low (up to 2%) relative abundance. We provide genomic evidence from our isolates demonstrating that the Arthrobacter and Pseudomonas isolates have the potential to respire nitrate and oxygen, though dissimilatory nitrate reduction could not be confirmed in laboratory cultures. The cultures from this study represent members of abundant phyla, as determined by amplicon sequencing of environmental DNA extracts, and allow for further studies into geochemical factors impacting life in the deep subsurface.

  12. An efficient screening method for the isolation of heterotrophic bacteria influencing growth of diatoms under photoautotrophic conditions.

    Science.gov (United States)

    Zecher, Karsten; Jagmann, Nina; Seemann, Philipp; Philipp, Bodo

    2015-12-01

    Interactions between photoautotrophic diatoms and heterotrophic bacteria are important for the biogeochemical C-cycle in the oceans. Additionally, biofilms formed by diatoms and bacteria are the initiating step of biofouling processes, which causes high costs in shipping. Despite this ecological and economical importance, the knowledge about biochemical and molecular mechanisms underlying these interkingdom interactions is relatively small. For analyzing these mechanisms, laboratory model systems are required. In this study, an efficient screening method for isolating bacteria influencing photoautotrophic diatom growth was established. First, diatom cultures of Phaeodactylum tricornutum and Thalassiosira pseudonana were made axenic by applying β-lactam antibiotics. Second, a non-invasive method for measuring growth of multiple parallel diatom cultures by chlorophyll fluorescence was established. This method allowed semi-quantitative chlorophyll determination of cultures with up to 3 μg (chlorophyll) ml(-1). Axenic diatom cultures were then used for enriching bacteria and led to the isolation of 24 strains influencing growth of both diatom strains in various ways. For example, Rheinheimera sp. strain Tn16 inhibited growth of T. pseudonana, while it stimulated growth and cell aggregation of P. tricornutum. Thus, this screening method is appropriate for isolating heterotrophic bacteria showing different interactions with different diatom species ranging from synergistic to antagonistic. In consecutive applications, this method will be useful to screen for bacterial mutants with altered phenotypes regarding the influence on diatom growth.

  13. Influence of Asellus aquaticus on Escherichia coli, Klebsiella pneumoniae, Campylobacter jejuni and naturally occurring heterotrophic bacteria in drinking water

    DEFF Research Database (Denmark)

    Christensen, Sarah Christine; Nissen, Erling; Arvin, Erik;

    2012-01-01

    . aquaticus on microbial water quality in non-chlorinated drinking water in controlled laboratory experiments. Pure cultures of the indicator organisms Escherichia coli and Klebsiella pneumoniae and the pathogen Campylobacter jejuni as well as naturally occurring heterotrophic drinking water bacteria...... (measured as heterotrophic plate counts, HPC) were investigated in microcosms at 7 °C, containing non-sterilised drinking water, drinking water sediment and A. aquaticus collected from a non-chlorinated ground water based drinking water supply system. Concentrations of E. coli, K. pneumoniae and C. jejuni...... grown on R-2A agar and an average of 83% for bacteria grown on yeast extract agar when dead A. aquaticus were present compared to no and living A. aquaticus present. A. aquaticus associated E. coli, K. pneumoniae and C. jejuni were measured (up to 25 per living and 500 per dead A. aquaticus) and so were...

  14. Effects of mercury contamination on the culturable heterotrophic, functional and genetic diversity of the bacterial community in soil

    DEFF Research Database (Denmark)

    Rasmussen, Lasse Dam; Sørensen, S. J.

    2001-01-01

    . The culturable heterotrophic diversity was investigated by colony morphology and colony appearance on solid LB medium. Functional diversity was analysed as sole carbon utilisation patterns in ECOplates. Genetic diversity was measured as bands on denaturing gradient gel electrophoresis (DGCE) gels obtained...... analysed by Shannon-Weaver indices, functional diversity was found to increase almost immediately after mercury addition and to remain at a level higher than the control soil for the rest of the experiment. The fraction of culturable heterotrophic bacteria increased from 1% to 10% of the total bacterial...

  15. Overestimation of heterotrophic bacteria in the Sargasso Sea: direct evidence by flow and imaging cytometry

    Science.gov (United States)

    Sieracki, Michael E.; Haugen, Elin M.; Cucci, Terry L.

    1995-08-01

    Accurate measurements of bacterial biomass in the ocean are needed for modeling marine microbial food webs and global biogeochemical cycling. We present direct evidence that previous estimates of heterotrophic bacteria biomass in the oligotrophic ocean are confounded by the presence of the abundant photosynthetic procaryote, Prochlorococcus. The chlorophyll autofluorescence of these photosynthetic bacterial cells is very faint and fades rapidly under epifluorescence microscopy. Detection and enumeration of these cells thus far has almost exclusively been by flow cytometry. Using a cooled, charge-coupled device (CCD) camera we were able to image these cells for direct biovolume measurements. A double-exposed image of DAPI-stained Prochlorococcus cells shows that they are indistinguishable from heterotrophic bacteria in standard slide preparations. At two Sargasso Sea stations Prochlorococcus could cause an overestimation of surface (top 150 m) integrated heterotrophic bacterial biovolume (biomass) of 18 and 22% determined by standard microscope methods. At the subsurface chlorophyll maximum Prochlorococcus was 33 and 43% of the heterotrophic bacterial biovolume (biomass) at these stations. Prochlorococcus cell size increased from 0.05 μm 3 in the surface mixed layer to about 0.2 μm 3 below 100 m, confirming previous interpretations of flow cytometric light scatter measurements. Shifting biomass from the heterotrophic bacteria pool to the primary producer compartment has significant implications for ecosystem structure and trophic transfer in marine food webs.

  16. Incidence of Legionella and heterotrophic bacteria in household rainwater tanks in Azumino, Nagano prefecture, Japan.

    Science.gov (United States)

    Kobayashi, Michiko; Oana, Kozue; Kawakami, Yoshiyuki

    2014-01-01

    Many administrative agencies in Japan are encouraging installation of household rainwater-storage tanks for more effective use of natural rainwater. Water samples were collected periodically from 43 rainwater tanks from 40 households and tested for the presence of Legionella species and the extent of heterotrophic bacteria in Azumino city, Nagano prefecture, Japan. PCR assays indicated the presence of Legionella spp. in 12 (30%) of the 43 tank water samples. Attempts were made to identify correlations between PCR positive samples, topography, pH, chemical oxygen demand (COD), atmospheric temperature and the numbers of heterotrophic bacteria. Between June and October, 2012, the numbers of heterotrophic bacteria in rainwater tanks and the values of COD positively correlated with the presence of Legionella species. In most of the Legionella-positive cases, heterotrophic bacterial cell counts were >10(4) CFU/mL. Moreover, Legionella species were less frequently detected when the COD value was >5 mg KMnO(4)/L. Therefore, at least in Azumino, Japan between June and October 2012, both heterotrophic bacterial counts and COD values may be considered index parameters for the presence of Legionella cells in rainwater tanks. Much more accumulation of such data is needed to verify the accuracy of these findings.

  17. Elevated temperature increases carbon and nitrogen fluxes between phytoplankton and heterotrophic bacteria through physical attachment

    KAUST Repository

    Arandia-Gorostidi, Nestor

    2016-12-06

    Quantifying the contribution of marine microorganisms to carbon and nitrogen cycles and their response to predicted ocean warming is one of the main challenges of microbial oceanography. Here we present a single-cell NanoSIMS isotope analysis to quantify C and N uptake by free-living and attached phytoplankton and heterotrophic bacteria, and their response to short-term experimental warming of 4 °C. Elevated temperature increased total C fixation by over 50%, a small but significant fraction of which was transferred to heterotrophs within 12 h. Cell-to-cell attachment doubled the secondary C uptake by heterotrophic bacteria and increased secondary N incorporation by autotrophs by 68%. Warming also increased the abundance of phytoplankton with attached heterotrophs by 80%, and promoted C transfer from phytoplankton to bacteria by 17% and N transfer from bacteria to phytoplankton by 50%. Our results indicate that phytoplankton-bacteria attachment provides an ecological advantage for nutrient incorporation, suggesting a mutualistic relationship that appears to be enhanced by temperature increases.

  18. Heterotrophic Bacteria Show Weak Competition for Nitrogen in Mediterranean Coastal Waters (Thau Lagoon) in Autumn.

    Science.gov (United States)

    Trottet, Aurore; Leboulanger, Christophe; Vidussi, Francesca; Pete, Romain; Bouvy, Marc; Fouilland, Eric

    2016-02-01

    The importance of heterotrophic bacteria relative to phytoplankton in the uptake of ammonium and nitrate was studied in Mediterranean coastal waters (Thau Lagoon) during autumn, when the Mediterranean Sea received the greatest allochthonous nutrient loads. Specific inhibitors and size-fractionation methods were used in combination with isotopic (15)N tracers. NO3 (-) and NH4 (+) uptake was dominated by phytoplankton (60 % on average) during the study period, which included a flood event. Despite lower biomass specific NH4 (+) and NO3 uptake rates, free-living heterotrophic bacteria contributed significantly (>30 %) to total microbial NH4 (+) and NO3 (-) uptake rates in low chlorophyll waters. Under these conditions, heterotrophic bacteria may be responsible for more than 50 % of primary production, using very little freshly produced phytoplankton exudates. In low chlorophyll coastal waters as reported during the present 3-month study, the heterotrophic bacteria seemed to depend to a greater extent on allochthonous N and C substrates than on autochthonous substrates derived from phytoplankton.

  19. Isolation and life cycle characterization of lytic viruses infecting heterotrophic bacteria and cyanobacteria

    DEFF Research Database (Denmark)

    Middelboe, Mathias; Chan, Amy; Bertelsen, Sif Koldborg

    2010-01-01

    Basic knowledge on viruses infecting heterotrophic bacteria and cyanobacteria is key to future progress in understanding the role of viruses in aquatic systems and the influence of virus–host interactions on microbial mortality, biogeochemical cycles, and genetic exchange. Such studies require th...

  20. Influence of Asellus aquaticus on Escherichia coli, Klebsiella pneumoniae, Campylobacter jejuni and naturally occurring heterotrophic bacteria in drinking water.

    Science.gov (United States)

    Christensen, Sarah C B; Nissen, Erling; Arvin, Erik; Albrechtsen, Hans-Jørgen

    2012-10-15

    Water lice, Asellus aquaticus (isopoda), frequently occur in drinking water distribution systems where they are a nuisance to consumers and water utilities. Whether they are solely an aesthetic problem or also affect the microbial water quality is a matter of interest. We studied the influence of A. aquaticus on microbial water quality in non-chlorinated drinking water in controlled laboratory experiments. Pure cultures of the indicator organisms Escherichia coli and Klebsiella pneumoniae and the pathogen Campylobacter jejuni as well as naturally occurring heterotrophic drinking water bacteria (measured as heterotrophic plate counts, HPC) were investigated in microcosms at 7 °C, containing non-sterilised drinking water, drinking water sediment and A. aquaticus collected from a non-chlorinated ground water based drinking water supply system. Concentrations of E. coli, K. pneumoniae and C. jejuni decreased over time, following a first order decay with half lives of 5.3, 18.4 and 1.3 days, respectively. A. aquaticus did not affect survival of indicators and pathogens substantially whereas HPC were influenced by presence of dead A. aquaticus. Growth rates increased with an average of 48% for bacteria grown on R-2A agar and an average of 83% for bacteria grown on yeast extract agar when dead A. aquaticus were present compared to no and living A. aquaticus present. A. aquaticus associated E. coli, K. pneumoniae and C. jejuni were measured (up to 25 per living and 500 per dead A. aquaticus) and so were A. aquaticus associated heterotrophic bacteria (>1.8*10(4) CFU per living and >6*10(4) CFU per dead A. aquaticus). A. aquaticus did not serve as an optimised habitat that increased survival of indicators and pathogens, since A. aquaticus associated E. coli, K. pneumoniae and C. jejuni were only measured as long as the bacteria were also present in the water and sediment.

  1. Response of Marine Microalgae, Heterotrophic Bacteria and Their Relationship to Enhanced UV-B Radiation

    Institute of Scientific and Technical Information of China (English)

    ZHOU Wenli; TANG Xuexi; XIAO Hui; WANG You; WANG Renjun

    2009-01-01

    Ozone depletion in the stratosphere has enhanced solar UV-B radiation reaching the Earth surface and has brought about significant effects to marine ecosystems. The effects of enhanced UV-B radiation on marine microalgae, heterotrophic bacteria and the interaction between them are discussed. The effects on marine microalgae have been proved to occur at molecular, cellular and population levels. Enhanced UV-B radiation increases microalgal flavonoid content but decreases their chlorophyll content and pho-tosynthesis rate; this rachation induces genetic change and results in DNA damage and change of protein content. There have been fewer studies on the effects of UV-B radiation on marine heterotrophic bacteria. Establishment of a nucroalgal ecological dynamic model at population and community levels under UV-B radiation has gradually become a hotspot. The effects of enhanced UV-B radiation on microalgae communities, heterotrophic bacterial populations and interaction between them will become a focus in the near future. This paper will make an overview on the studies concerning the effects of enhanced UV-B radiation on marine microal-gae and heterotrophic bacteria and the interaction between them.

  2. Distribution Pattern of Photosynthetic Picoplankton and Heterotrophic Bacteria in the Northern South China Sea

    Institute of Scientific and Technical Information of China (English)

    Yu-Ming Cai; Xiu-Ren Ning; Cheng-Gang Liu; Qiang Hao

    2007-01-01

    The environmental regulation of picoplankton distribution in the northern South China Sea was examined in winter and summer of 2004. The average abundance of Synechococcus, Prochlorococcus, and heterotrophic bacteria was lower in winter (30, 21, and 780×103 cells/cm3, respectively) than in summer (53, 85, and 1 090×103 cells/cm3,respectively), but the seasonal pattern was opposite for plcoeukaryotic phytoplankton (4 500 and 3 200 cells/cm3 in winter and summer, respectively). Synechococcus, picoeukaryotes, and bacteria were most abundant in the nutrient-rich coastal zone and continental shelf, but Prochlorococcus was most abundant in the continental slope and open ocean. The vertical distribution of each photosynthetic group and heterotrophic bacteria changed between the two seasons. Synechococcus populations with apparently different phycoerythrobilln content occurred at many stations in the summer. In addition, two different populations of Prochlorococcus were found: (i) small, weakly fluorescing cells in the surface layer; and (ii) larger, strongly fluorescent cells in the deep layer. The distribution pattern of photosynthetic picoplankton and heterotrophic bacteria depends on environmental effects and their ecophysiological differences. The distribution of Synechococcus appeared to be related to nutrient availability,whereas the distribution of Prochlorococcus appeared to be limited by temperature. Synechococcus was the only picophytoplankton with a consistent strong relationship with bacteria.

  3. Stoichiometric flexibility in diverse aquatic heterotrophic bacteria is coupled to differences in cellular phosphorus quotas

    Directory of Open Access Journals (Sweden)

    Casey Michael Godwin

    2015-02-01

    Full Text Available It is frequently presumed that heterotrophic bacteria from aquatic environments have low carbon (C content, high phosphorus (P content, and maintain homeostasis at low C:P in their biomass. Dissolved and particulate organic matter from primary producers in terrestrial and aquatic environments typically has high C:P ratios, suggesting that heterotrophic bacteria consuming this resource experience stoichiometric imbalance in C and P. The strength of elemental homeostasis is important for understanding how heterotrophic bacteria couple C and P cycles in response to environmental change, yet these generalizations are based upon data from only a few species that might not represent the physiology of bacteria in freshwaters. However, recent research has indicated that some strains of bacteria isolated from freshwaters have flexible C:P stoichiometry and can acclimate to changes in resource C:P. Although it is apparent that strains differ in their biomass C:P and flexibility, the basis for these characteristics has not been explained. We evaluated biomass C:P homeostasis in 24 strains of bacteria isolated from temperate lakes using a uniform relative growth rate in chemostats. Overall, the strains exhibited a range of homeostatic regulation from strong homeostasis to highly flexible biomass stoichiometry, but strains that were isolated using P-rich media formulations were more homeostatic than strains isolated using P-poor media. Strains exhibiting homeostatic biomass C:P had high cellular C and P content and showed little morphological change between C and P limitation. In contrast, stoichiometrically flexible strains had low P quotas and increased their C quotas and cell size under P limitation. Because stoichiometric flexibility is closely coupled to absolute P content in bacteria, anthropogenic inputs of P could lead to prevalence of more homeostatic bacteria, reducing the ability of natural assemblages to buffer changes in the availability of P

  4. Cold-Active, Heterotrophic Bacteria from the Highly Oligotrophic Waters of Lake Vanda, Antarctica

    Directory of Open Access Journals (Sweden)

    Nicole A. Vander Schaaf

    2015-07-01

    Full Text Available The permanently ice-covered lakes of the McMurdo Dry Valleys, Antarctica are distinctive ecosystems that consist strictly of microbial communities. In this study, water samples were collected from Lake Vanda, a stratified Dry Valley lake whose upper waters (from just below the ice cover to nearly 60 m are highly oligotrophic, and used to establish enrichment cultures. Six strains of psychrotolerant, heterotrophic bacteria were isolated from lake water samples from a depth of 50 or 55 m. Phylogenetic analyses showed the Lake Vanda strains to be species of Nocardiaceae, Caulobacteraceae, Sphingomonadaceae, and Bradyrhizobiaceae. All Lake Vanda strains grew at temperatures near or below 0 °C, but optimal growth occurred from 18 to 24 °C. Some strains showed significant halotolerance, but no strains required NaCl for growth. The isolates described herein include cold-active species not previously reported from Dry Valley lakes, and their physiological and phylogenetic characterization broadens our understanding of these limnologically unique lakes.

  5. Auto- and heterotrophic acidophilic bacteria enhance the bioremediation efficiency of sediments contaminated by heavy metals.

    Science.gov (United States)

    Beolchini, Francesca; Dell'Anno, Antonio; De Propris, Luciano; Ubaldini, Stefano; Cerrone, Federico; Danovaro, Roberto

    2009-03-01

    This study deals with bioremediation treatments of dredged sediments contaminated by heavy metals based on the bioaugmentation of different bacterial strains. The efficiency of the following bacterial consortia was compared: (i) acidophilic chemoautotrophic, Fe/S-oxidising bacteria, (ii) acidophilic heterotrophic bacteria able to reduce Fe/Mn fraction, co-respiring oxygen and ferric iron and (iii) the chemoautotrophic and heterotrophic bacteria reported above, pooled together, as it was hypothesised that the two strains could cooperate through a mutual substrate supply. The effect of the bioremediation treatment based on the bioaugmentation of Fe/S-oxidising strains alone was similar to the one based only on Fe-reducing bacteria, and resulted in heavy-metal extraction yields typically ranging from 40% to 50%. The efficiency of the process based only upon autotrophic bacteria was limited by sulphur availability. However, when the treatment was based on the addition of Fe-reducing bacteria and the Fe/S oxidizing bacteria together, their growth rates and efficiency in mobilising heavy metals increased significantly, reaching extraction yields >90% for Cu, Cd, Hg and Zn. The additional advantage of the new bioaugmentation approach proposed here is that it is independent from the availability of sulphur. These results open new perspectives for the bioremediation technology for the removal of heavy metals from highly contaminated sediments.

  6. Ultraviolet reduction of erythromycin and tetracycline resistant heterotrophic bacteria and their resistance genes in municipal wastewater.

    Science.gov (United States)

    Guo, Mei-Ting; Yuan, Qing-Bin; Yang, Jian

    2013-11-01

    Antibiotic resistance in wastewater is becoming a major public health concern, but poorly understood about impact of disinfection on antibiotic resistant bacteria and antibiotic resistance genes. The UV disinfection of antibiotic resistant heterotrophic bacteria and their relevant genes in the wastewater of a municipal wastewater treatment plant has been evaluated. Two commonly used antibiotics, erythromycin and tetracycline were selected because of their wide occurrences in regard to the antibiotic resistance problem. After UV treatment at a fluence of 5mJcm(-2), the log reductions of heterotrophic bacteria resistant to erythromycin and tetracycline in the wastewater were found to be 1.4±0.1 and 1.1±0.1, respectively. The proportion of tetracycline-resistant bacteria (5%) was nearly double of that before UV disinfection (3%). Tetracycline-resistant bacteria exhibited more tolerance to UV irradiation compared to the erythromycin-resistant bacteria (pUV treatment at a fluence of 5mJcm(-2) removed the total erythromycin- and tetracycline-resistance genes by 3.0±0.1 log and 1.9±0.1 log, respectively. UV treatment was effective in reducing antibiotic resistance in the wastewater.

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

    DEFF Research Database (Denmark)

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

    2009-01-01

    Multi-species biofilm modeling has been used for many years to understand the interactions between species in different biofilm systems, but the complex symbiotic relationship between species is sometimes overlooked, because models do not always include all relevant species and components....... In this paper, we develop and use a mathematical model to describe a model biofilm system that includes autotrophic and heterotrophic bacteria and the key products produced by the bacteria. The model combines the methods of earlier multi-species models with a multi-component biofilm model in order to explore...

  8. Recolonization by heterotrophic bacteria after UV irradiation or ozonation of seawater; a simulation of ballast water treatment.

    Science.gov (United States)

    Hess-Erga, Ole-Kristian; Blomvågnes-Bakke, Bente; Vadstein, Olav

    2010-10-01

    Transport of ballast water with ships represents a risk for introduction of foreign species. If ballast water is treated during uptake, there will be a recolonization of the ballast water by heterotrophic bacteria during transport. We investigated survival and succession of heterotrophic bacteria after disinfection of seawater in the laboratory, representing a model system of ballast water treatment and transport. The seawater was exposed to ultraviolet (UV) irradiation, ozone (2 doses) or no treatment, incubated for 16 days and examined with culture-dependent and -independent methods. The number of colony-forming units (CFU) was reduced below the detection level after disinfection with UV and high ozone dose (700 mV), and 1% of the initial level for the low ozone dose (400 mV). After less than 3 days, the CFU was back or above the starting point for the control, UV and low ozone treatment, whereas it took slightly more than 6 days for the high ozone treatment. Disinfection increased substrate availability and reduced cell densities. Lack of competition and predation induced the recolonization by opportunistic bacteria (r-strategists), with significant increase in bacterial numbers and a low diversity (based on DGGE band pattern). All cultures stabilized after the initial recolonization phase (except Oz700) where competition due to crowding and nutrient limitation favoured bacteria with high substrate affinity (K-strategists), resulting in higher species richness and diversity (based on DGGE band pattern). The bacterial community was significantly altered qualitatively and quantitatively and may have a higher potential as invaders in the recipient depending on disinfection method and the time of release. These results have implications for the treatment strategy used for ballast water.

  9. Health concerns of heterotrophic plate count (HPC) bacteria in dental equipment water lines.

    Science.gov (United States)

    Allen, Martin J; Edberg, Stephen C

    2016-06-01

    There is an unsubstantiated concern as to the health relevance of HPC (heterotrophic plate count) bacteria in dental equipment waterlines. The American Dental Association (ADA) web site includes guidelines for controlling HPC populations and implies that HPC populations >500 CFU/mL as a "health" benchmark. The world-wide published literature including the United Nations fully examined this situation and concluded that HPC bacteria are not a health risk, but merely a general water quality parameter for all waters including dental water lines. This review provides documentation that the standard measurement of HPC bacteria in waters alone do not pose a health risk and the ADA already provides appropriate practices to minimize HPC bacteria in dental equipment water.

  10. The Biology of Heterotrophic N2-fixing Bacteria in Marine and Estuarine Waters

    DEFF Research Database (Denmark)

    Bentzon-Tilia, Mikkel

    the potential to fix significant amounts of N2 at cell densities equivalent to densities observed in the environment from which they were isolated. Hence, N2 fixation by heterotrophic bacteria are likely important in some marine environments. However, the scale and spatial extent of the heterotrophic N2......Biological nitrogen (N)2 fixation is of paramount importance for marine N cycling and for life in the oceans in general. It represents the sole mechanism by which microorganisms can channel inert atmospheric N2 gas into biomass and hence it may fuel a significant fraction of primary production...... in certain aquatic environments. The capability of fixing N2 is restricted to the prokaryotes, but its genetic potential is distributed between a diverse assortment of organisms (diazotrophs) within the bacterial and archeal domains. Traditionally, the colonial cyanobacterium Trichodesmium, various...

  11. Ecophysiological properties of cultivable heterotrophic bacteria and yeasts dominating in phytocenoses of Galindez Island, maritime Antarctica.

    Science.gov (United States)

    Vasileva-Tonkova, Evgenia; Romanovskaya, Victoria; Gladka, Galina; Gouliamova, Dilnora; Tomova, Iva; Stoilova-Disheva, Margarita; Tashyrev, Oleksandr

    2014-04-01

    Antarctic plants are stable specific microenvironments for microbial colonization that are still less explored. In this study, we investigated cultivable heterotrophic bacteria and yeasts dominating in plant samples collected from different terrestrial biotopes near Ukrainian Antarctic Base on Galindez Island, maritime Antarctica. Phylogenetic analysis revealed affiliation of the bacterial isolates to genera Pseudomonas, Stenotrophomonas, Brevundimonas, Sporosarcina, Dermacoccus, Microbacterium, Rothia and Frondihabitans, and the yeast isolates to genera Rhodosporidium, Cryptococcus, Leucosporidiella, Candida and Exophiala. Some ecophysiological properties of isolated strains were determined that are important in response to different stresses such as psychro- and halotolerance, UV-resistance and production of hydrolytic enzymes. The majority of isolates (88 %) was found to be psychrotolerant; all are halotolerant. Significant differences in survival subsequent to UV-C radiation were observed among the isolates, as measured by culturable counts. For the bacterial isolates, lethal doses in the range 80-600 J m⁻² were determined, and for the yeast isolates--in the range 300-1,000 J m⁻². Dermacoccus profundi U9 and Candida davisiana U6 were found as most UV resistant among the bacterial and yeast isolates, respectively. Producers of caseinase, gelatinase, β-glucosidase, and cellulase were detected. To the best of our knowledge, this is the first report on isolation of UV resistant strain D. profundi, and Frondihabitans strain from Antarctica, and on detection of cellulase activity in Antarctic yeast strain C. davisiana. The results obtained contribute to clarifying adaptation strategies of Antarctic microbiota and its possible role in functional stability of Antarctic biocenoses. Stress tolerant strains were detected that are valuable for ecological and applied studies.

  12. Genomics and Ecophysiology of Heterotrophic Nitrogen-Fixing Bacteria Isolated from Estuarine Surface Water.

    Science.gov (United States)

    Bentzon-Tilia, Mikkel; Severin, Ina; Hansen, Lars H; Riemann, Lasse

    2015-07-07

    The ability to reduce atmospheric nitrogen (N2) to ammonia, known as N2 fixation, is a widely distributed trait among prokaryotes that accounts for an essential input of new N to a multitude of environments. Nitrogenase reductase gene (nifH) composition suggests that putative N2-fixing heterotrophic organisms are widespread in marine bacterioplankton, but their autecology and ecological significance are unknown. Here, we report genomic and ecophysiology data in relation to N2 fixation by three environmentally relevant heterotrophic bacteria isolated from Baltic Sea surface water: Pseudomonas stutzeri strain BAL361 and Raoultella ornithinolytica strain BAL286, which are gammaproteobacteria, and Rhodopseudomonas palustris strain BAL398, an alphaproteobacterium. Genome sequencing revealed that all were metabolically versatile and that the gene clusters encoding the N2 fixation complex varied in length and complexity between isolates. All three isolates could sustain growth by N2 fixation in the absence of reactive N, and this fixation was stimulated by low concentrations of oxygen in all three organisms (≈ 4 to 40 µmol O2 liter(-1)). P. stutzeri BAL361 did, however, fix N at up to 165 µmol O2 liter(-1), presumably accommodated through aggregate formation. Glucose stimulated N2 fixation in general, and reactive N repressed N2 fixation, except that ammonium (NH4 (+)) stimulated N2 fixation in R. palustris BAL398, indicating the use of nitrogenase as an electron sink. The lack of correlations between nitrogenase reductase gene expression and ethylene (C2H4) production indicated tight posttranscriptional-level control. The N2 fixation rates obtained suggested that, given the right conditions, these heterotrophic diazotrophs could contribute significantly to in situ rates. The biological process of importing atmospheric N2 is of paramount importance in terrestrial and aquatic ecosystems. In the oceans, a diverse array of prokaryotes seemingly carry the genetic capacity

  13. Active nitrogen-fixing heterotrophic bacteria at and below the chemocline of the central Baltic Sea.

    Science.gov (United States)

    Farnelid, Hanna; Bentzon-Tilia, Mikkel; Andersson, Anders F; Bertilsson, Stefan; Jost, Günter; Labrenz, Matthias; Jürgens, Klaus; Riemann, Lasse

    2013-07-01

    The Baltic Sea receives large nitrogen inputs by diazotrophic (N2-fixing) heterocystous cyanobacteria but the significance of heterotrophic N2 fixation has not been studied. Here, the diversity, abundance and transcription of the nifH fragment of the nitrogenase enzyme in two basins of the Baltic Sea proper was examined. N2 fixation was measured at the surface (5 m) and in anoxic water (200 m). Vertical sampling profiles of >10 and bacteria (nifH cluster III) at and below the chemocline. Abundances of genes and transcripts of seven diazotrophic phylotypes were investigated using quantitative polymerase chain reaction revealing abundances of heterotrophic nifH phylotypes of up to 2.1 × 10(7) nifH copies l(-1). Abundant nifH transcripts (up to 3.2 × 10(4) transcripts l(-1)) within nifH cluster III and co-occurring N2 fixation (0.44±0.26 nmol l(-1) day(-1)) in deep water suggests that heterotrophic diazotrophs are fixing N2 in anoxic ammonium-rich waters. Our results reveal that N2 fixation in the Baltic Sea is not limited to illuminated N-deplete surface waters and suggest that N2 fixation could also be of importance in other suboxic regions of the world's oceans.

  14. Interactions of the metal tolerant heterotrophic microorganisms and iron oxidizing autotrophic bacteria from sulphidic mine environment during bioleaching experiments.

    Science.gov (United States)

    Jeremic, Sanja; Beškoski, Vladimir P; Djokic, Lidija; Vasiljevic, Branka; Vrvić, Miroslav M; Avdalović, Jelena; Gojgić Cvijović, Gordana; Beškoski, Latinka Slavković; Nikodinovic-Runic, Jasmina

    2016-05-01

    Iron and sulfur oxidizing chemolithoautotrophic acidophilic bacteria, such as Acidithiobacillus species, hold the dominant role in mine environments characterized by low pH values and high concentrations of reduced sulfur and iron compounds, such as ores, rocks and acid drainage waters from mines. On the other hand, heterotrophic microorganisms, especially their biofilms, from these specific niches are receiving increased attention, but their potential eco-physiological roles have not been fully understood. Biofilms are considered a threat to human health, but biofilms also have beneficial properties as they are deployed in waste recycling and bioremediation systems. We have analyzed interactions of the metal tolerant heterotrophic microorganisms in biofilms with iron oxidizing autotrophic bacteria both from the sulphidic mine environment (copper mine Bor, Serbia). High tolerance to Cu(2+), Cd(2+) and Cr(6+) and the presence of genetic determinants for the respective metal tolerance and biofilm-forming ability was shown for indigenous heterotrophic bacteria that included strains of Staphylococcus and Rhodococcus. Two well characterized bacteria- Pseudomonas aeruginosa PAO1 (known biofilm former) and Cupriavidus metallidurans CH34 (known metal resistant representative) were also included in the study. The interaction and survivability of autotrophic iron oxidizing Acidithiobacillus bacteria and biofilms of heterotrophic bacteria during co-cultivation was revealed. Finally, the effect of heterotrophic biofilms on bioleaching process with indigenous iron oxidizing Acidithiobacillus species was shown not to be inhibitory under in vitro conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. An enrichment and acclimation procedure to obtain photo heterotrophic cultures for H{sub 2} production from organic effluents

    Energy Technology Data Exchange (ETDEWEB)

    Acevedo-Benitez, J. A.; Ponce-Noyola, M. T.; Poggi-Varaldo, H. M.

    2009-07-01

    Production of H{sub 2} via photo heterotrophic is an attractive alternative, due to the capacity of photo heterotrophic organisms to convert the organic matter of effluents into H{sub 2}. The objective of our work was to develop a protocol for selecting undefined mixed cultures of photo heterotrophic microorganism with the capability of producing of H{sub 2}. (Author)

  16. Occurrence of heterotrophic and coliform bacteria in liquid hand soaps from bulk refillable dispensers in public facilities.

    Science.gov (United States)

    Chattman, Marisa; Gerba, Sheri L; Maxwell, Charles P

    2011-03-01

    The goal of the study discussed in this article was to determine the occurrence of heterotrophic and coliform bacteria in liquid soap from bulk refillable dispensers, obtained from restrooms in a variety of public facilities. A total of 541 samples was collected from five U.S. cities. Liquid soap from dispensers in public areas was found to contain heterotrophic and coliform bacterial numbers averaging more than 106 CFU/mL in 24.8% of the dispensers.

  17. Killing of total heterotrophic bacteria using the gas diffusion electrode system.

    Science.gov (United States)

    Xu, W Y; Li, P

    2012-06-01

    This study focused on the disinfection of dual electrodes with a gas diffusion cathode using total heterotrophic bacteria as indicator microorganisms. Batch tests were performed to study the effects of platinum load W(Pt) and the pore-forming agent content WNH4HCO3 in gas diffusion electrodes on the germicidal efficacy eta and H2O2 yield. The results showed that the disinfection improved with W(Pt), but its efficiency at W(Pt) of 3 per thousand was equivalent to W(Pt) of 4 per thousand. The right amount of the pore-forming agent improved disinfection. Continuous tests were performed to study residence times (RTs), pH and oxygen flow rates Qo2 on the germicidal efficacy and H2O2 yield. The results indicated that at the steady state total heterotrophic bacteria in the outlet stream were completely inactivated under our experimental conditions. Disinfection improved with increasing RT. This phenomenon was more significant when RT disinfection shortened with an increasing oxygen flow rate Qo2. The operating costs are high. Further research is required to fully understand all parameters and reduce operating costs.

  18. Effect of electro-stimulation on activity of heterotrophic denitrifying bacteria and denitrification performance.

    Science.gov (United States)

    Liu, Hengyuan; Tong, Shuang; Chen, Nan; Liu, Ying; Feng, Chuanping; Hu, Qili

    2015-11-01

    The effects of electro-stimulation on heterotrophic denitrifying bacterial activity and nitrate removal were investigated using a bench-scale bio-electrochemical reactor in this study. Results showed that the maximum nitrate removal efficiency was 100% at the optimum current density of 200mA/m(2), at which low nitrite production and high ATP aggregate level were obtained. The activity of denitrifying bacteria was highest at the range densities of 200-250mA/m(2), although the terminative pH increased to 8.62 at 200mA/m(2) and 9.63 at 250mA/m(2). This demonstrates that suitable current densities could improve the activity of denitrifying bacteria. Therefore, this study provides a number of useful information to improve the bio-electrochemical reactor designs and promote the removal efficiency of pollutants. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Heterotrophic bacteria of the Dapeng Bay in the South China Sea: community structure, abundance, and the relationships of culturablity with environmental factors

    Institute of Scientific and Technical Information of China (English)

    JIANG Fajun; HU Zhangli; HU Chaoqun

    2010-01-01

    The community composition,abundance and culturablity of heterotrophic bacterioplankton in the Dapeng Bay of the South China Sea were investigated by morphological method,bacterial cultivation and biochemical methods over an annual cycle.Aeromonas and Pseudomonas were the predominant genera among the Gram-negative bacteria.The bacterioplankton abundance fluctuated from 2.07×10s to 2.44×109 cells/dm3,and culturable bacteria abundance ranged between0.1×106 and 16.07×106 CFU/dm3.The Culturablity of heterotrophic bacteria ranged between0.01% and 1.31%.The relationship between bacterial culturablity and the environmental factors was also studied in different sites of the Dapeng Bay.Throughout the bay,a significantly positive relationship was evidenced between bacterial culturability and temperature,meanswhile bacterial culturability was significantly inversely related with salinity.The positive relationship was shown at the central bay while a negative relationship was observed at the bay mouth and there was no significant correlation at top bay between bacterial culturablity and chlorophyll a of sea water.A positive relationship was found between culturability and DIN all the bay,but DIP showed a significantly negative relationship with bacterial culturability only at the mouth of the bay.

  20. Inactivation of Heterotrophic Bacteria in Well Water Using ZVI, TiO2 and ZnO Nanoparticles

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Zazuli

    2016-07-01

    Full Text Available Background & Aims of the Study: The heterotrophic bacteria are widely used as a water microbial pollution index for drinking water. The aim of this study was to investigate the effect of metallic nanoparticles such as Zero Valent Iron (ZVI, Titanium dioxide (TiO2 and Zinc oxide (ZnO on Heterotrophic Bacteria inactivation in well water. Materials & Methods: We performed an experimental-laboratory study that the effect of nanoparticles type Zero valent iron (ZVI, Titanium Dioxide (TiO2 and Zinc oxide (ZnO in constant contact time (30 min and nanoparticles dose (1 g/L was investigated on heterotrophic bacteria inactivation. Results: The results showed that TiO2 was detected more effective than ZnO and ZVI. The HPC inactivation after 30 min of retention time by TiO2, ZnO and ZVI nanoparticles were 71.5, 50 and 36.4 as percent, respectively. The maximum bacteria inactivation was 98.82% in the presence of TiO2 nanoparticles. Conclusions: It is concluded that nanoparticles used in this study could be effectively used to increase the efficiency of removing heterotrophic bacteria from water and can be considered for microorganisms’ inactivation.

  1. Massive regime shifts and high activity of heterotrophic bacteria in an ice-covered lake.

    Directory of Open Access Journals (Sweden)

    Mina Bižić-Ionescu

    Full Text Available In winter 2009/10, a sudden under-ice bloom of heterotrophic bacteria occurred in the seasonally ice-covered, temperate, deep, oligotrophic Lake Stechlin (Germany. Extraordinarily high bacterial abundance and biomass were fueled by the breakdown of a massive bloom of Aphanizomenon flos-aquae after ice formation. A reduction in light resulting from snow coverage exerted a pronounced physiological stress on the cyanobacteria. Consequently, these were rapidly colonized, leading to a sudden proliferation of attached and subsequently of free-living heterotrophic bacteria. Total bacterial protein production reached 201 µg C L(-1 d(-1, ca. five times higher than spring-peak values that year. Fluorescence in situ hybridization and denaturing gradient gel electrophoresis at high temporal resolution showed pronounced changes in bacterial community structure coinciding with changes in the physiology of the cyanobacteria. Pyrosequencing of 16S rRNA genes revealed that during breakdown of the cyanobacterial population, the diversity of attached and free-living bacterial communities were reduced to a few dominant families. Some of these were not detectable during the early stages of the cyanobacterial bloom indicating that only specific, well adapted bacterial communities can colonize senescent cyanobacteria. Our study suggests that in winter, unlike commonly postulated, carbon rather than temperature is the limiting factor for bacterial growth. Frequent phytoplankton blooms in ice-covered systems highlight the need for year-round studies of aquatic ecosystems including the winter season to correctly understand element and energy cycling through aquatic food webs, particularly the microbial loop. On a global scale, such knowledge is required to determine climate change induced alterations in carbon budgets in polar and temperate aquatic systems.

  2. Massive regime shifts and high activity of heterotrophic bacteria in an ice-covered lake.

    Science.gov (United States)

    Bižić-Ionescu, Mina; Amann, Rudolf; Grossart, Hans-Peter

    2014-01-01

    In winter 2009/10, a sudden under-ice bloom of heterotrophic bacteria occurred in the seasonally ice-covered, temperate, deep, oligotrophic Lake Stechlin (Germany). Extraordinarily high bacterial abundance and biomass were fueled by the breakdown of a massive bloom of Aphanizomenon flos-aquae after ice formation. A reduction in light resulting from snow coverage exerted a pronounced physiological stress on the cyanobacteria. Consequently, these were rapidly colonized, leading to a sudden proliferation of attached and subsequently of free-living heterotrophic bacteria. Total bacterial protein production reached 201 µg C L(-1) d(-1), ca. five times higher than spring-peak values that year. Fluorescence in situ hybridization and denaturing gradient gel electrophoresis at high temporal resolution showed pronounced changes in bacterial community structure coinciding with changes in the physiology of the cyanobacteria. Pyrosequencing of 16S rRNA genes revealed that during breakdown of the cyanobacterial population, the diversity of attached and free-living bacterial communities were reduced to a few dominant families. Some of these were not detectable during the early stages of the cyanobacterial bloom indicating that only specific, well adapted bacterial communities can colonize senescent cyanobacteria. Our study suggests that in winter, unlike commonly postulated, carbon rather than temperature is the limiting factor for bacterial growth. Frequent phytoplankton blooms in ice-covered systems highlight the need for year-round studies of aquatic ecosystems including the winter season to correctly understand element and energy cycling through aquatic food webs, particularly the microbial loop. On a global scale, such knowledge is required to determine climate change induced alterations in carbon budgets in polar and temperate aquatic systems.

  3. Impact of Sulfur Starvation in Autotrophic and Heterotrophic Cultures of the Extremophilic Microalga Galdieria phlegrea (Cyanidiophyceae).

    Science.gov (United States)

    Carfagna, Simona; Bottone, Claudia; Cataletto, Pia Rosa; Petriccione, Milena; Pinto, Gabriele; Salbitani, Giovanna; Vona, Vincenza; Pollio, Antonino; Ciniglia, Claudia

    2016-09-01

    In plants and algae, sulfate assimilation and cysteine synthesis are regulated by sulfur (S) accessibility from the environment. This study reports the effects of S deprivation in autotrophic and heterotrophic cultures of Galdieria phlegrea (Cyanidiophyceae), a unicellular red alga isolated in the Solfatara crater located in Campi Flegrei (Naples, Italy), where H2S is the prevalent form of gaseous S in the fumarolic fluids and S is widespread in the soils near the fumaroles. This is the first report on the effects of S deprivation on a sulfurous microalga that is also able to grow heterotrophically in the dark. The removal of S from the culture medium of illuminated cells caused a decrease in the soluble protein content and a significant decrease in the intracellular levels of glutathione. Cells from heterotrophic cultures of G. phlegrea exhibited high levels of internal proteins and high glutathione content, which did not diminish during S starvation, but rather glutathione significantly increased. The activity of O-acetylserine(thiol)lyase (OASTL), the enzyme synthesizing cysteine, was enhanced under S deprivation in a time-dependent manner in autotrophic but not in heterotrophic cells. Analysis of the transcript abundance of the OASTL gene supports the OASTL activity increase in autotrophic cultures under S deprivation.

  4. Distribution of general aerobic heterotrophic bacteria in sediment core taken from the Canadian basin and the Chukchi Sea

    Institute of Scientific and Technical Information of China (English)

    Gao Aiguo; Chen Haowen

    2008-01-01

    The occurrence percentage and abundance of General Aerobic Heterotrophic Bacteria (GAB) were determined by using the method of MPN for 182 subsamples from 10 sediment cores taken from the Canadian basin and the Chukchi Sea at two different culturing temperatures.The results showed that the general occurrencepercentage of GAB was quite high,average abundances of GAB at cultured temperatures of 4℃ and 25℃ were 4.46 ×107 and 5.47×107 cells·g -1 (wt), respectively.The highest abundance of GAB occurred at 20~22 cm section in the sediment.GAB abundances changed among the section of sediments,but there is a trend: the abundances at the middle or lower sections were lower than those at upper section.Cultivation at 25℃ could improve the occurrence percentage and abundances of GAB,which suggests that the increasing of temperature may change the living circumstances of GAB.The differences of GAB among the latitudes areas indicated thatoccurrence percentage and abundances of GAB in middle latitude areas were higher than those in the higher or lower latitude areas,and were more obvious at 4℃than those at 25℃.The GAB abundances in sediment under the shallower water seemed to be lower than those in sediments under the deeper water and this status was more obvious at 25℃ than that at 4℃.

  5. Olivine dissolution in the presence of heterotrophic bacteria (Pseudomonas reactants) extracted from Icelandic groundwater of the CO2 injection pilot site

    Science.gov (United States)

    Shirokova, Liudmila; Pokrovsky, Oleg; Benezeth, Pascale; Gerard, Emmanuelle; Menez, Benedicte; Alfredsson, Helgi

    2010-05-01

    This work is aimed at experimental modeling of the effect of heterotrophic bacteria on dissolution of important rock-forming mineral, olivine, at the conditions of CO2 storage and sequestration. Heterotrophic aerobic gram-negative bacteria were extracted from deep underground water (HK31, 1700 m deep and, t = 25-30°C) of basaltic aquifer located within the Hellisheidi CO2 injection pilot site (Iceland). Following this sampling, we separated, using culture on nutrient agar plates, four different groups of gram-negative aerobic bacteria. The enzymatic activity of studied species has been evaluated using Biolog Ecoplates and their genetic identification was performed using 18-S RNA analysis. The optimal growth conditions of bacteria on Brain Hearth Broth nutrient have been determined as 5 to 37°C and growth media pH varied from 7.0-8.2. Culturing experiments allowed determining the optimal physico-chemical conditions for bacteria experiments in the presence of basic Ca, Mg-containing silicates. Olivine (Fo92) was chosen as typical mineral of basalt, widely considered in carbon dioxide sequestration mechanisms. Dissolution experiments were performed in constant-pH (7 to 9), bicarbonate-buffered (0.001 to 0.05 M) nutrient-diluted media in batch reactors at 0-30 bars of CO2 in the presence of various biomass of Pseudomonas reactants. The release rate of magnesium, silica and iron was measured as a function of time in the presence of live, actively growing, dead (autoclaved or glutaraldehyde-treated) cells and bacteria exometabolites. Both nutrient media diluted 10 times (to 100 mg DOC/L) and inert electrolyte (NaCl, no DOC) were used. Our preliminary results indicate that the pH and dissolved organic matter are the first-order parameters that control the element release from olivine at far from equilibrium conditions. The SEM investigation of reacted surfaces reveal formation of surface roughness with much stronger mineral alteration in the presence of live bacteria

  6. Heterotrophic bacteria from brackish water of the southern Baltic Sea: biochemical and molecular identification and characterisation

    Directory of Open Access Journals (Sweden)

    Agnieszka Cabaj

    2006-12-01

    Full Text Available Six bacterial strains isolated from the surface water of thesouthern Baltic Sea were described on the basis of their morphological,physiological and biochemical features, and were classified onthe basis of 16S rDNA sequence analysis. Comparative analysesof the 16S rDNA sequences of five of the six bacterial strainsexamined displayed a ≥98% similarity to the sequences availablein the NCBI GenBank. The 16S rDNA sequence of strain 2 sharedonly a 96% similarity with other published sequences, whichsuggests that this is a new, hitherto unknown species. The isolatedheterotrophic bacteria belong to the families Bacillaceae(strain 1, Flexibacteriaceae (strain 2, Sphingomonadaceae(strains 3, 5, Micrococcaceae (strain 4 and Aurantimonadaceae(strain 6.    This is the first study in which the polyphasic approach hasbeen applied to the identification of heterotrophic bacteriafrom the brackish waters of the Gulf of Gdańsk and Gdańsk Deep.

  7. Analysis the Existence of Heterotrophic Bacteria in Active Water Desalination Plant Output of Kashan City, Iran

    Directory of Open Access Journals (Sweden)

    Hosseindoost Gh. MSc,

    2015-12-01

    Full Text Available Aims One of the consequences of taking ground water into surface is changing its chemical quality, specially increasing the concentration of dissolved salts. This research was performed in order to analyze growth possibility of heterotrophic bacteria in the membrane of active desalination plants in Kashan City, Iran. Instrument & Methods This descriptive cross-sectional study was done on water output of 20 active desalination plants in 2013 in Kashan City, Iran and 200 specimens of input and output water was randomly extracted from desalination plants. Awareness and education level of system operators, filter changing intervals, HPC of input and output water and chlorine concentration of input and output water were measured and recorded. Obtained data were analyzed statistically with SPSS 18 software using one-way ANOVA, Chi-square, McNemar and one-sample T tests. Findings There was a significant relation between the interval time and output HPC level of the plants (p0.05. The mean concentration of chlorine in samples of 20 desalination plants was 0.76±0.44mg/l in input water and 0.64±0.52mg/l in output water (p>0.05. Level of awareness had significant relation with the output water pollution with HPC (p0.05. Conclusion The mean level of HPC

  8. Contrasting life strategies of viruses that infect photo- and heterotrophic bacteria, as revealed by viral tagging.

    Science.gov (United States)

    Deng, Li; Gregory, Ann; Yilmaz, Suzan; Poulos, Bonnie T; Hugenholtz, Philip; Sullivan, Matthew B

    2012-10-30

    Ocean viruses are ubiquitous and abundant and play important roles in global biogeochemical cycles by means of their mortality, horizontal gene transfer, and manipulation of host metabolism. However, the obstacles involved in linking viruses to their hosts in a high-throughput manner bottlenecks our ability to understand virus-host interactions in complex communities. We have developed a method called viral tagging (VT), which combines mixtures of host cells and fluorescent viruses with flow cytometry. We investigated multiple viruses which infect each of two model marine bacteria that represent the slow-growing, photoautotrophic genus Synechococcus (Cyanobacteria) and the fast-growing, heterotrophic genus Pseudoalteromonas (Gammaproteobacteria). Overall, viral tagging results for viral infection were consistent with plaque and liquid infection assays for cyanobacterial myo-, podo- and siphoviruses and some (myo- and podoviruses) but not all (four siphoviruses) heterotrophic bacterial viruses. Virus-tagged Pseudoalteromonas organisms were proportional to the added viruses under varied infection conditions (virus-bacterium ratios), while no more than 50% of the Synechococcus organisms were virus tagged even at viral abundances that exceeded (5 to 10×) that of their hosts. Further, we found that host growth phase minimally impacts the fraction of virus-tagged Synechococcus organisms while greatly affecting phage adsorption to Pseudoalteromonas. Together these findings suggest that at least two contrasting viral life strategies exist in the oceans and that they likely reflect adaptation to their host microbes. Looking forward to the point at which the virus-tagging signature is well understood (e.g., for Synechococcus), application to natural communities should begin to provide population genomic data at the proper scale for predictively modeling two of the most abundant biological entities on Earth. Viral study suffers from an inability to link viruses to hosts en

  9. Survey on Heterotrophic Bacterial Contamination in Bottled Mineral Water by Culture Method

    OpenAIRE

    Essmaeel Ghorbanalinezhad; Ghazaleh Saeedi; Delaram Khanjani

    2014-01-01

    Background and Aim: This project focuses on the level of heterotrophic baceria in bottled mineral water which could be a health concern for the elderly, infants, pregnant women and immuno-compromised patients. Materials and Methods: Different brands of bottled water samples were selected randomly and evaluated for their bacteriological quality, using different specific culture media and biochemical tests. Water samples were analyzed within 24 hours of their purchase/collection. Samples we...

  10. The Biology of Heterotrophic N2-fixing Bacteria in Marine and Estuarine Waters

    DEFF Research Database (Denmark)

    Bentzon-Tilia, Mikkel

    cyanobacterial endosymbionts of diatoms, and recently also unicellular cyanobacteria, have been considered the dominant marine diazotrophs. However, phylogenetic analyses of the functional genes involved in N2 fixation seem to suggest that heterotrophic N2-fixing organisms are present and active in various...... and that a subset of these could be subsequently isolated for further genomic and ecophysiological analyses. Such analyses showed that regulation of N2 fixation in heterotrophs are not straightforward and in many cases it is counterintuitive. Furthermore, they showed that individual heterotrophic strains have...

  11. Population of Aerobic Heterotrophic Nitrogen-Fixing Bacteria Associated with Wetland and Dryland Rice

    OpenAIRE

    Barraquio, W.L.; de Guzman, M. R.; Barrion, M.; Watanabe, I.

    1982-01-01

    Nitrogen-fixing activity and populations of nitrogen-fixing bacteria associated with two varieties of rice grown in dryland and wetland conditions were measured at various growth stages during the dry season. Acetylene reduction activities were measured both in the field and for the hydroponically grown rice, which was transferred from the field to water culture 1 day before assay. The activities measured by both methods were higher in wetland than in dryland rice. The population of nitrogen-...

  12. Photoautotrophic-heterotrophic biofilm communities: a laboratory incubator designed for growing axenic diatoms and bacteria in defined mixed-species biofilms.

    Science.gov (United States)

    Buhmann, Matthias; Kroth, Peter G; Schleheck, David

    2012-02-01

    Biofilm communities in the euphotic zone of aquatic habitats comprise photoautotrophic microorganisms, such as diatoms, green algae and cyanobacteria, which produce the organic carbon that fuels the life of a heterotrophic contingent of microorganisms, mostly bacteria. Such photoautotrophic-heterotrophic mixed-species biofilms have received little attention in biofilm research due to a lack of suitable pure-culture laboratory model systems. However, they offer important insight into microbial population dynamics and community interactions during a biofilm-developmental process that shapes highly structured, extremely well-adapted microbial landscapes. Here, we report on the development of a sterile incubation chamber for growing and monitoring axenic phototrophic biofilms, i.e. a sterilizable, illuminated, continuous-flow system for a routine work with pure cultures. The system has been designed to simulate the growth conditions in the shallow, littoral zone of aquatic habitats (horizontal surface, submerged in water, illuminated, aerated). Additional features of the concept include automated photometrical monitoring of biofilm density (as biofilm turbidity), analysis via confocal microscopy, direct harvesting of cells, and options to control illumination, flow velocity, and composition of culture fluid. The application of the system was demonstrated in growth experiments using axenic diatom biofilms, or axenic diatom biofilms co-cultivated with different bacterial strains isolated from epilithic biofilms of an oligotrophic freshwater lake. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

  13. Influence of the root system of the Common Osier (Salix viminalis L.) on abundance of heterotrophic bacteria in the willow sewage treatment system.

    Science.gov (United States)

    Lalke-Porczyk, Elzbieta; Brzezinska, Maria Swiontek; Donderski, Wojciech

    2009-06-01

    The impact of the Common Osier (Salix viminalis L.) root system on number (CFU) of heterotrophic bacteria and their production in a soil-willow filter was examined. The Osier rhizosphere was found to be suitable habitat for growth of the examined microbial group, and the root system stimulated development of heterotrophic bacteria. The rhizosphere bacteria to control soil bacteria (R:C) ratio oscillated between 2.48 and 2.75 depending on the location of sample collection. The highest abundance of bacteria as well as highest bacterial production was observed at location I, near sewage discharge onto the plot. There was a significant positive correlation between the number of heterotrophic bacteria and the bacterial production.

  14. Putative N2-fixing heterotrophic bacteria associated with dinoflagellate-Cyanobacteria consortia in the low-nitrogen Indian Ocean

    DEFF Research Database (Denmark)

    Farnelid, H.; Tarangkoon, Woraporn; Hansen, Gert

    2010-01-01

    that the symbionts fix gaseous nitrogen (N2). Individual heterotrophic dinoflagellates containing cyanobacterial symbionts were isolated from the open Indian Ocean and off Western Australia, and characterized using light microscopy, transmission electron microscopy (TEM), and nitrogenase (nifH) gene amplification......, cloning, and sequencing. Cyanobacteria, heterotrophic bacteria and eukaryotic algae were recognized as symbionts of the heterotrophic dinoflagellates. nifH gene sequences were obtained from 23 of 37 (62%) specimens of dinoflagellates (Ornithocercus spp. and Amphisolenia spp.). Interestingly, only 2...... specimens contained cyanobacterial nifH sequences, while 21 specimens contained nifH genes related to heterotrophic bacteria. Of the 137 nifH sequences obtained 68% were most similar to Alpha-, Beta-, and Gammaproteobacteria, 8% clustered with anaerobic bacteria, and 5% were related to second alternative...

  15. Coupling of heterotrophic bacteria to phytoplankton bloom development at different pCO2 levels: a mesocosm study

    Directory of Open Access Journals (Sweden)

    R. Thyrhaug

    2008-01-01

    Full Text Available The predicted rise in anthropogenic CO2 emissions will increase CO2 concentrations and decrease seawater pH in the upper ocean. Recent studies have revealed effects of pCO2 induced changes in seawater chemistry on a variety of marine life forms, in particular calcifying organisms. To test whether the predicted increase in pCO2 will directly or indirectly (via changes in phytoplankton dynamics affect abundance, activities, and community composition of heterotrophic bacteria during phytoplankton bloom development, we have aerated mesocosms with CO2 to obtain triplicates with three different partial pressures of CO2 (pCO2: 350 µatm (1×CO2, 700 µatm (2×CO2 and 1050 µatm (3×CO2. The development of a phytoplankton bloom was initiated by the addition of nitrate and phosphate. In accordance to an elevated carbon to nitrogen drawdown at increasing pCO2, bacterial production (BPP of free-living and attached bacteria as well as cell-specific BPP (csBPP of attached bacteria were related to the C:N ratio of suspended matter. These relationships significantly differed among treatments. However, bacterial abundance and activities were not statistically different among treatments. Solely community structure of free-living bacteria changed with pCO2 whereas that of attached bacteria seemed to be independent of pCO2 but tightly coupled to phytoplankton bloom development. Our findings imply that changes in pCO2, although reflected by changes in community structure of free-living bacteria, do not directly affect bacterial activity. Furthermore, bacterial activity and dynamics of heterotrophic bacteria, especially of attached bacteria, were tightly linked to phytoplankton development and, hence, may also potentially depend on changes in pCO2.

  16. Tracking heterotrophic and autotrophic carbon cycling by magnetotactic bacteria in freshwater sediments using DNA stable isotope probing

    Science.gov (United States)

    Kürşat Coşkun, Ömer; Roud, Sophie; He, Kuang; Petersen, Nikolai; Gilder, Stuart; Orsi, William D.

    2017-04-01

    Magnetotactic bacteria (MTB) are diverse, widespread, motile prokaryotes which biomineralize nanosize magnetic minerals, either magnetite or gregite, under highly conserved genetic control and have magnetotaxis to align their position in aquatic environment according to Earth's magnetic field. They play important roles on some geobiological cycle of important minerals such as iron, sulphur, nitrogen and carbon. Yet, to date, their importance in carbon cycle and carbon source in their natural environment have not been previously studied. In this study, we focused on freshwater benthic carbon cycling of MTB and total bacteria using DNA stable isotope probing (DNA-SIP) technique coupled with quantitative PCR (qPCR). Pond sediments from Unterlippach (Germany) were amended with 13C-labelled sodium bicarbonate and 13C-labelled organic matter, and incubated in the dark over a two week time period. Applying separate qPCR assays specific for total bacteria and MTB, respectively, allowed us to estimate the contribution of MTB to total heterotrophic and autotrophic carbon cycling via DNA-SIP. After one week, there was a slight degree of autotrophic activity which increased markedly after two weeks. Comparing total DNA to the qPCR data revealed that changes in the buoyant density of DNA was due mainly to autotrophic bacterial production. DNA-SIP also identified heterotrophic utilization of 13C-labelled organic matter by MTB after 1 week. The qPCR data also allowed us to estimate uptake rates based on the incubation times for heterotrophic and autotrophic MTB. High-throughput DNA sequencing of 16S rRNA genes showed that most of the MTB involved in carbon cycling were related to the Magnetococcus genus. This study sheds light on the carbon sources for MTB in a natural environment and helps unravel their ecological role in the carbon cycle.

  17. [Variation of bacteria numbers in fish-shrimp mix-culturing ecosystem].

    Science.gov (United States)

    Li, Qiufen; Chen, Bijuan; Qu, Keming; Yuan, Youxian; Li, Jian; Sun, Xiutao; Zhao, Fazhen

    2002-06-01

    The study on variation of bacteria numbers in Penaeus chinensis-fish mix-culturing ecosystem in 1997. Indicated that at the beginning of culturing season, total number of heterotrophic bacteria and that of nitrate-reducing bacteria in mix-culturing ponds was low, but it was higher than that in mono-culturing shrimp pond. With time going on, the number of bacteria in mono-culturing pond increased rapidly and remained at a high level in August and September, an that in mix-culturing ponds also increased. But the latter increased slowly, and it was never over 10(4) cells.ml-1 and dropped in September. Number of bacteria in bottom of the ponds varied with the similar regulation, but the numbers was 10-100 times higher. The numbers of vibrio in mix-culturing ponds was always lower than that in contrastive pond at the same time. So, in fish-shrimp mix-culturing ponds, the contents of organic matter were lower and the total amount and variability of phytoplankton were higher than corresponding items in mono-culturing pond. It was concluded that mix-culture could stimulate and control the growth of heterotrophic bacteria, accelerate the degradation of organic pollutants, consequently fasten and stabilize the circulation of mater in ecosystem of ponds in culturing season.

  18. Inference of Interactions in Cyanobacterial-Heterotrophic Co-Cultures via Transcriptome Sequencing

    Energy Technology Data Exchange (ETDEWEB)

    Beliaev, Alex S.; Romine, Margaret F.; Serres, Margaret; Bernstein, Hans C.; Linggi, Bryan E.; Markillie, Lye Meng; Isern, Nancy G.; Chrisler, William B.; Kucek, Leo A.; Hill, Eric A.; Pinchuk, Grigoriy; Bryant, Donald A.; Wiley, H. S.; Fredrickson, Jim K.; Konopka, Allan

    2014-04-29

    We employed deep sequencing technology to identify transcriptional adaptation of the euryhaline unicellular cyanobacterium Synechococcus sp. PCC 7002 and the marine facultative aerobe Shewanella putrefaciens W3-18-1 to growth in a co-culture and infer the effect of carbon flux distributions on photoautotroph-heterotroph interactions. The overall transcriptome response of both organisms to co-cultivation was shaped by their respective physiologies and growth constraints. Carbon limitation resulted in the expansion of metabolic capacities which was manifested through the transcriptional upregulation of transport and catabolic pathways. While growth coupling occurred via lactate oxidation or secretion of photosynthetically fixed carbon, there was evidence of specific metabolic interactions between the two organisms. On one hand, the production and excretion of specific amino acids (methionine and alanine) by the cyanobacterium correlated with the putative downregulation of the corresponding biosynthetic machinery of Shewanella W3-18-1. On the other hand, the broad and consistent decrease of mRNA levels for many Fe-regulated Synechococcus 7002 genes during co-cultivation suggested increased Fe availability as well as more facile and energy-efficient mechanisms for Fe acquisition by the cyanobacterium. Furthermore, evidence pointed at potentially novel interactions between oxygenic photoautotrophs and heterotrophs related to the oxidative stress response as transcriptional patterns suggested that Synechococcus 7002 rather than Shewanella W3-18-1 provided scavenging functions for reactive oxygen species under co-culture conditions. This study provides an initial insight into the complexity of photoautotrophic-heterotrophic interactions and brings new perspectives of their role in the robustness and stability of the association.

  19. Active nitrogen-fixing heterotrophic bacteria at and below the chemocline of the central Baltic Sea

    OpenAIRE

    Farnelid, Hanna; Bentzon-Tilia, Mikkel; Andersson, Anders F.; Bertilsson, Stefan; Jost, Günter; Labrenz, Matthias; Jürgens, Klaus; Riemann, Lasse

    2013-01-01

    The Baltic Sea receives large nitrogen inputs by diazotrophic (N2-fixing) heterocystous cyanobacteria but the significance of heterotrophic N2 fixation has not been studied. Here, the diversity, abundance and transcription of the nifH fragment of the nitrogenase enzyme in two basins of the Baltic Sea proper was examined. N2 fixation was measured at the surface (5 m) and in anoxic water (200 m). Vertical sampling profiles of >10 and

  20. Genomics and ecophysiology of heterotrophic nitrogen-fixing bacteria isolated from estuarine surface water

    DEFF Research Database (Denmark)

    Bentzon-Tilia, Mikkel; Severin, Ina; Hansen, Lars H.;

    2015-01-01

    ABSTRACT The ability to reduce atmospheric nitrogen (N 2) to ammonia, known as N 2 fixation, is a widely distributed trait among prokaryotes that accounts for an essential input of new N to a multitude of environments. Nitrogenase reductase gene (nifH) composition suggests that putative N 2-fixing...... heterotrophic organisms are widespread in marine bacterioplankton, but their autecology and ecological significance are unknown. Here, we report genomic and ecophysiology data in relation to N 2 fixation by three environmentally ...

  1. Distribution and enzymatic activity of heterotrophic bacteria decomposing selected macromolecular compounds in a Baltic Sea sandy beach

    Science.gov (United States)

    Podgórska, B.; Mudryk, Z. J.

    2003-03-01

    The potential capability to decompose macromolecular compounds, and the level of extracellular enzyme activities were determined in heterotrophic bacteria isolated from a sandy beach in Sopot on the Southern Baltic Sea coast. Individual isolates were capable of hydrolysing a wide spectrum of organic macromolecular compounds. Lipids, gelatine, and DNA were hydrolyzed most efficiently. Only a very small percentage of strains were able to decompose cellulose, and no pectinolytic bacteria were found. Except for starch-hydrolysis, no significant differences in the intensity of organic compound decomposition were recorded between horizontal and vertical profiles of the studied beach. Of all the studied extracellular enzymes, alkaline phosphatase, esterase lipase, and leucine acrylaminidase were most active; in contrast, the activity α-fucosidase, α-galactosidase and β-glucouronidase was the weakest. The level of extracellular enzyme activity was similar in both sand layers.

  2. Evaluation of growth yield of Spirulina (Arthrospira) sp. in photoautotrophic, heterotrophic and mixotrophic cultures.

    Science.gov (United States)

    Chojnacka, Katarzyna; Zielińska, Agnieszka

    2012-02-01

    In microbial cultures, both cellular growth rate and yield (defined as the degree of substrate conversion into the biomass) are important. Although effect of culture conditions on growth kinetics has been well documented for various microbial strains, there is almost no literature concerning the effect of environmental conditions on growth equilibrium, expressed as biomass yield coefficients from substrate. The present paper discusses the effect of culture conditions: irradiance (physical substrate) and glucose concentration (chemical substrate) on biomass yield coefficients from two chemical substrates: glucose and nitrate-nitrogen in photoautotrophic, heterotrophic and mixotrophic culture of blue-green alga Spirulina (Arthrospira) sp. The efficiency of substrates incorporation into the biomass can be precisely determined only if the elemental composition of the biomass is known. The experimental results showed that culture conditions had a substantial influence on biomass yield coefficients (biomass yield from glucose and nitrate-nitrogen). It was found that, the increase of irradiance favoured increase of biomass yield coefficient from both, glucose and nitrate-nitrogen. However, in the case of yield from nitrogen in mixotrophic culture, the effect was opposite. The effect of glucose concentration was different: the higher the initial glucose concentration, the lower the biomass yield coefficients from chemical substrates.

  3. Multiple antibiotic resistance of heterotrophic bacteria in the littoral zone of Lake Shira as an indicator of human impact on the ecosystem.

    Science.gov (United States)

    Lobova, Tatiana I; Barkhatov, Yuri V; Salamatina, Ol'ga V; Popova, Lyudmila Yu

    2008-01-01

    Resistance to Ampicillin and Kanamycin displayed by heterotrophic bacteria isolated in Summer and in Spring from the littoral and the central parts of Lake Shira (a therapeutic lake in the Khakasia Republic, Russia) has been investigated. It has been found that in Summer, human and animal microflora featuring multiple antibiotic resistance (to Ampicillin and Kanamycin) predominates in all the studied stations of the littoral zone of the lake. In Spring, concentrations of bacteria featuring multiple antibiotic resistance decrease significantly and bacteria sensitive to antibiotics predominate in the lake. Emergence of multiple antibiotic resistance in bacteria of Lake Shira is caused by the input of allochthonous bacteria into the lake; this feature of heterotrophic bacteria of Lake Shira can be used to monitor the impact on the ecosystem made by health resorts.

  4. Densities, cellulases, alginate and pectin lyases of luminous and other heterotrophic bacteria associated with marine algae

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaiah, N.; Chandramohan, D.

    Epiphytic luminous and non-luminous bacteria were determined quantitatively for eight intertidal algal species from rocky beaches of Goa and Lakshadweep coral reef lagoon. Luminous bacteria were present on all eight algal species and contributed 2...

  5. Occurrence of heterotrophic bacteria and fungi in an aviation fuel handling system and its relationship with fuel fouling.

    Science.gov (United States)

    Ferrari, M D; Neirotti, E; Albornoz, C

    1998-01-01

    Clean, dry and contaminant-free fuel is necessary for safe and economical aircraft operation. Microbial growth in aviation fuel handling systems can alter the quality of the product. This paper reports the occurrence of heterotrophic bacteria and fungi in a handling system of jet A-1 aviation turbine fuel. A total of 350 samples were collected during 1990-1996. The aerobic microorganisms in fuel samples were mainly fungi, 85% of samples containing < or = 100 cfu/l (range 0 (< 1 cfu/l) to 2000 cfu/l). The predominant fungi were Cladosporium and Aspergillus. Water was observed mainly in samples extracted from the drainage pipes of two tanks used frequently as intermediate storage tanks. The aerobic heterotrophic microorganisms found in water samples were mostly bacteria, counts varying from 100 to 8.8 x 10(7) cfu/ml, with 85% of samples containing 10(4)-10(7) cfu/ml. There was a preponderance of Pseudomonas spp. Bacterial contaminants belonging to the genus Flavobacterium and Aeromonas were also identified. Sulphate reducing bacteria were detected in 80% of water samples. It was not possible to assign a maximum microbial contamination level above which maintenance is required and it is suggested that analysis of successive samples from the same site are necessary for this purpose. Microbial sludges produced in the laboratory and collected from a contaminated tank bottom were analysed chemically. The data are presented and discussed. Samples collected from the supply pipes of tanks and refueller trucks during the period surveyed always met the standard specifications.

  6. Abundance of general aerobic heterotrophic bacteria in the Bering Sea and Chukchi Sea and their adaptation to temperature

    Institute of Scientific and Technical Information of China (English)

    陈皓文; 高爱国; 孙海青; 矫玉田

    2004-01-01

    The abundance of general aerobic heterotrophic bacteria(GAB) from the water and sediment in the Bering Sea and the Chukchi Sea was determined by using petri dish cultivation and counting method. The abundance of GAB among the different sea areas, sampling sites, layers of sediments surveyed and adaptability to differential temperatures was studied. The result obtained showed that: the occurrence percentage of GAB in the surface water was higher than that in sediment, but the abundance was only 0.17% of sediment. The occurrence percentage of GAB in surficial layer of sediment was higher than that in the other layers. The occurrence percentage of GAB in surficial layer of sediment was higher than that in the other layers. The occurrence percentage, abundance and its variation of GAB in the Bering Sea were higher than that in the Chukchi Sea respectively. The average value of the abundance of GAB in sediment showed a trend: roughly higher in the lower latitudinal area than higher latitude. The results from temperature test mean that: the majority of bacteria tested were cold -adapted ones, minority might be mesophilic bacteria. The results indicated that, Arctic ocean bacteria had a stronger adaptability to environmental temperature.

  7. Relatively high antibiotic resistance among heterotrophic bacteria from arctic fjord sediments than water - Evidence towards better selection pressure in the fjord sediments

    Science.gov (United States)

    Hatha, A. A. Mohamed; Neethu, C. S.; Nikhil, S. M.; Rahiman, K. M. Mujeeb; Krishnan, K. P.; Saramma, A. V.

    2015-12-01

    The objective of this study was to determine the prevalence of antibiotic resistance among aerobic heterotrophic bacteria and coliform bacteria from water and sediment of Kongsfjord. The study was based on the assumption that arctic fjord environments are relatively pristine and offer very little selection pressure for drug resistant mutants. In order to test the hypothesis, 200 isolates belonging to aerobic heterotrophic bacteria and 114 isolates belonging to coliforms were tested against 15 antibiotics belonging to 5 different classes such as beta lactams, aminoglycosides, quinolones, sulpha drugs and tetracyclines. Resistance to beta lactam and extended spectrum beta lactam (ESBL) antibiotics was considerably high and they found to vary significantly (p antibiotic resistance against ESBL's extent and diversity of antibiotic resistance (as revealed by multiple antibiotic resistance index and resistance patterns), was high in the aerobic heterotrophic bacteria. Most striking observation was that isolates from fjord sediments (both heterotrophic bacteria and coliforms) in general showed relatively high prevalence of antibiotic resistance against most of the antibiotics tested, indicating to better selection pressure for drug resistance mutants in the fjord sediments.

  8. Biological removal of nitrate by an oil reservoir culture capable of autotrophic and heterotrophic activities: kinetic evaluation and modeling of heterotrophic process.

    Science.gov (United States)

    An, Shijie; Stone, Heather; Nemati, Mehdi

    2011-06-15

    Kinetics of heterotrophic denitrification was investigated using an oil reservoir culture with the ability to function under both autotrophic and heterotrophic conditions. In the batch system nitrate at concentrations up to 30 mM did not influence the kinetics but with 50mM slower growth and removal rates were observed. A kinetic model, representing the denitrification as reduction of nitrate to nitrite, and subsequent reduction of nitrite to nitrous oxides and nitrogen gas was developed. The value of various kinetic coefficients, including maximum specific growth rate, saturation constant, yield and activation energy for nitrate and nitrite reductions were determined by fitting the experimental data into the developed model. In continuous bioreactors operated with 10 or 30 mM nitrate, complete removal of nitrate (no residual nitrite) and linear dependency between nitrate loading and removal rates were observed for loading rates up to 0.21 and 0.58 mM h(-1), respectively. The highest removal rates of 0.31 and 0.94 mM h(-1) observed at loading rates of 0.42 mM h(-1) and 1.26 mM h(-1), with corresponding removal percentages of nitrate and total nitrogen being 75.4, 54.4%, and 74.4 and 17.9%, respectively. Developed kinetic model predicted the performance of the continuous bioreactors with accuracy.

  9. Photochemical Production and Behavior of Hydroperoxyacids in Heterotrophic Bacteria Attached to Senescent Phytoplanktonic Cells

    Directory of Open Access Journals (Sweden)

    Frédéric Vaultier

    2013-06-01

    Full Text Available The photooxidation of cellular monounsaturated fatty acids was investigated in senescent phytoplanktonic cells (Emiliania huxleyi and in their attached bacteria under laboratory controlled conditions. Our results indicated that UV-visible irradiation of phytodetritus induced the photooxidation of oleic (produced by phytoplankton and bacteria and cis-vaccenic (specifically produced by bacteria acids. These experiments confirmed the involvement of a substantial singlet oxygen transfer from senescent phytoplanktonic cells to attached bacteria, and revealed a significant correlation between the concentration of chlorophyll, a photosensitizer, in the phytodetritus and the photodegradation state of bacteria. Hydroperoxyacids (fatty acid photoproducts appeared to be quickly degraded to ketoacids and hydroxyacids in bacteria and in phytoplanktonic cells. This degradation involves homolytic cleavage (most likely induced by UV and/or transition metal ions and peroxygenase activity (yielding epoxy acids.

  10. Polyphasic approach to characterize heterotrophic bacteria of biofilms and patina on walls of the Suburban Bath of the Herculaneum's archaeological excavations in Italy

    Science.gov (United States)

    Ventorino, V.; Pepe, O.; Sannino, L.; Blaiotta, G.; Palomba, S.

    2012-04-01

    plates were purified in the same growth medium by streaking and differentiated by assessing their morphological (phase-contrast microscopy) and biochemical characteristics (Gram-stains KOH-lysis and catalase activity). Cultural-based method allow us to identify by 16S and 26S rRNA partial sequence analysis, heterotrophic bacteria belonging to different genera as Bacillus, Pseudomonas, Aeromonas and Microbacterium. By using this approach, Bacillus-related species (B. benzoevorans, B. megaterium and B. pumilis and B. megaterium/B. simplex group) as well as Aeromonas sobria/Aeromonas salmonicida/Aeromonas hydrophila group, Pseudomonas plecoglossicida and Microbacterium esteraromaticum were isolated in different sample points analysed. DGGE analysis of PCR amplified V3 region of rDNA from DNA directly recovered from samples of biofilms and patina, enabled identification of bacterial species not found using culturable technology, as those closest related to Aeromonas, Paenibacillus, Brevibacterium, Exiguobacterium, Microbacterium, Brevibacterium, Stenothophomonas and Streptomyces. Combination of culture-dependent and independent methods provide a better characterization of heterotrophic microbiota that colonize the surface of ancient decorated walls and can contribute to understand the potential of biodeterioration activity by heterotrophic microorganisms.

  11. DISTRIBUTION OF BACTERIA IN SHELLFISH CULTURE AREA AROUND QINGDAO

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Bacteria numbers in water of coastal shellfish culture area around Qingdao were examined in April, August and October 1998 respectively. The results showed that the total numbers of heterotrophic and coliform bacteria in waters of the area and the specific geographical area varied with seasons. The highest populations were recorded during summer, I.e. 1.0×104~4.5×106cell/ml and 3.0×100~2.4×103cell/100ml, and with average values of 1.61×105cell/ml and 1.24×102cell/100ml respectively. The second highest populations occurred in autumn, and the lowest were in spring. The numbers of coliform bacteria were relatively low in waters near the mouths of bays and open part of the shellfish culture area, while those in waters near the estuaries of big rivers, wharves, navigation routes or the area in front of downtown areas were much higher than other areas. Single-index assessment of the environment quality of shellfish culture was made to indicate that the water sanitary quality in most of these areas are very good, however, some parts were serious polluted by the faeces of warm-blood animals. These results provided theoretical reference for the programming and organizing of shellfish culture.

  12. Seasonal variations of virus- and nanoflagellate-mediated mortality of heterotrophic bacteria in the coastal ecosystem of subtropical western Pacific

    Directory of Open Access Journals (Sweden)

    A. Y. Tsai

    2013-05-01

    Full Text Available Since viral lysis and nanoflagellate grazing differ in their impact on the aquatic food web, it is important to assess the relative importance of both bacterial mortality factors. In this study, an adapted version of the modified dilution method was applied to simultaneously estimate the impact of both virus and nanoflagellate grazing on the mortality of heterotrophic bacteria. A series of experiments was conducted monthly from April to December 2011 and April to October 2012. The growth rates of bacteria we measured ranged from 0.078 h−1 (April 2011 to 0.42 h−1 (September 2011, indicating that temperature can be important in controlling the seasonal variations of bacterial growth. Furthermore, it appeared that seasonal changes in nanoflagellate grazing and viral lysis could account for 34% to 68% and 13% to 138% of the daily removal of bacterial production, respectively. We suggest that nanoflagellate grazing might play a key role in controlling bacterial biomass and might exceed the impact of viral lysis during the summer period (July to August because of the higher abundance of nanoflagellates at that time. Viral lysis, on the other hand, was identified as the main cause of bacterial mortality between September and December. Based on these findings in this study, the seasonal variations in bacterial abundance we observed can be explained by a scenario in which both growth rates and loss rates (grazing + viral lysis influence the dynamics of the bacteria community.

  13. Heterotrophic high cell-density fed-batch cultures of the phycocyanin-producing red alga Galdieria sulphuraria.

    Science.gov (United States)

    Schmidt, Rikke Ankerstjerne; Wiebe, Marilyn G; Eriksen, Niels Thomas

    2005-04-05

    Growth and phycocyanin production in batch and fed-batch cultures of the microalga Galdieria sulphuraria 074G, which was grown heterotrophically in darkness on glucose, fructose, sucrose, and sugar beet molasses, was investigated. In batch cultures, specific growth rates and yields of biomass dry weight on the pure sugars were 1.08-1.15 day-1 and 0.48-0.50 g g-1, respectively. They were slightly higher when molasses was the carbon source. Cellular phycocyanin contents during the exponential growth phase were 3-4 mg g-1 in dry weight. G. sulphuraria was able to tolerate concentrations of glucose and fructose of up to 166 g L-1 (0.9 M) and an ammonium sulfate concentration of 22 g L-1 (0.17 M) without negative effects on the specific growth rate. When the total concentration of dissolved substances in the growth medium exceeded 1-2 M, growth was completely inhibited. In carbon-limited fed-batch cultures, biomass dry weight concentrations of 80-120 g L-1 were obtained while phycocyanin accumulated to concentrations between 250 and 400 mg L-1. These results demonstrate that G. sulphuraria is well suited for growth in heterotrophic cultures at very high cell densities, and that such cultures produce significant amounts of phycocyanin. Furthermore, the productivity of phycocyanin in the heterotrophic fed-batch cultures of G. sulphuraria was higher than is attained in outdoor cultures of Spirulina platensis, where phycocyanin is presently obtained.

  14. The effect of urban landfill leachate characteristics on the coexistence of anammox bacteria and heterotrophic denitrifiers.

    Science.gov (United States)

    Ruscalleda, M; Puig, S; Mora, X; López, H; Ganigué, R; Balaguer, M D; Colprim, J

    2010-01-01

    Heterotrophic denitrification coexists with the anammox process contributing to N removal owing to the biodegradable organic matter supply from urban landfill leachate and the decay of microorganisms. Both biomasses consumed nitrite increasing the nitrite requirements of the system. The aim of this paper is the study of the causes which induce the system to decrease nitrogen removal efficiency. In this study, urban landfill leachate has been treated in an anammox Sequencing Batch Reactor (SBR) for 360 days. The anammox reactor treated on average 0.24 kgN m(-3) d(-1) obtaining nitrogen removal efficiencies up to 89%. The results demonstrated that i) a suitable influent nitrite to ammonium molar ratio is a crucial factor to avoid troubles in the anammox reactor performance; ii) an excess of nitrite implied nitrite accumulation in the reactor; iii) a lower nitrite supply than the necessary for the system could force a loss of specific anammox activity due to nitrite competition with denitrifiers. These results pointed out the importance of the previous partial-nitritation process control in order to obtain a correct influent nitrite to ammonium molar ratio for the anammox reactor. In addition, sudden variation of the leachate characteristics must be avoided.

  15. Virioplankton in the Kara Sea: The impact of viruses on mortality of heterotrophic bacteria

    Science.gov (United States)

    Kopylov, A. I.; Sazhin, A. F.; Zabotkina, E. A.; Romanova, N. D.

    2015-07-01

    Studies were conducted in shallow and deepwater areas of the Kara Sea. The abundance of bacteria ( N B ) and the abundance of viruses ( N V ) ranged within (19.4-2215.1) × 103 cells/ml and (97.6-5796.8) × 103 particles/ml, respectively. The virus to bacteria ratio varied from 1.4 to 29.1. A positive correlation was found between N B and N V ( R = 0.87, n = 45, p = 0.05. Using electron transmission microscopy it was detected that the frequency of visibly infected cells of bacteria (FVIC) varied from 0.2 to 1.9% of N B . The maximum values of FVIC were recorded in the estuary of the Yenisei River. The infected cells of bacteria contained from 4 to 127 (an average of 12) phages/cell of mature viruses. Virus-mediated mortality of bacteria was 0.5% and varied from 1.4 to 16.1% of the total mortality of bacterioplankton. This indicates a minor role of viruses in the control of overabundance and production of bacterioplankton in the Kara Sea during the surveyed period.

  16. A comparison of effects of several herbicides on photoautotrophic, photomixotrophic and heterotrophic cultured tobacco cells and seedlings.

    Science.gov (United States)

    Sato, F; Takeda, S; Yamada, Y

    1987-12-01

    The effects of herbicides with different primary modes of action were examined on the growth of photoautotrophic, photomixotrophic, and heterotrophic cultures of tobacco cells. These responses were compared with those of tobacco seedlings to the same herbicides. Herbicides, which primarily inhibit or disturb photosynthetic processes, suppressed the growth of photoautotrophic cells most strongly, as compared to photomixotrophic and heterotrophic cells (atrazine, diuron, paraquat). Herbicides having a primary mode of action other than the inhibition of photosynthetic processes, suppressed the growth of all types of cultured cells at similar concentrations (2,4-D, diphenamid, glyphosate, dinoseb, sodium chlorate, bialaphos, DTP), but the photoautotrophic cells were still the most sensitive to all kinds of herbicides except sodium chlorate. Furthermore, photoautotrophic cells responded to most of the herbicides as did the seedlings, with the exception of glyphosate and diphenamid. The possibility of photoautotrophically cultured cells as a model system to study the effects of herbicides are discussed.

  17. Aquatic heterotrophic bacteria have highly flexible phosphorus content and biomass stoichiometry.

    Science.gov (United States)

    Godwin, Casey M; Cotner, James B

    2015-10-01

    Bacteria are central to the cycling of carbon (C), nitrogen (N) and phosphorus (P) in every ecosystem, yet our understanding of how tightly these cycles are coupled to bacterial biomass composition is based upon data from only a few species. Bacteria are commonly assumed to have high P content, low biomass C:P and N:P ratios, and inflexible stoichiometry. Here, we show that bacterial assemblages from lakes exhibit unprecedented flexibility in their P content (3% to less than 0.01% of dry mass) and stoichiometry (C:N:P of 28: 7: 1 to more than 8500: 1200: 1). The flexibility in C:P and N:P stoichiometry was greater than any species or assemblage, including terrestrial and aquatic autotrophs, and suggests a highly dynamic role for bacteria in coupling multiple element cycles.

  18. Cultivation and biochemical characterization of heterotrophic bacteria associated with phytoplankton bloom in the Amundsen sea polynya, Antarctica

    Science.gov (United States)

    Choi, Seon-Bin; Kim, Jong-Geol; Jung, Man-Young; Kim, So-Jeong; Min, Ui-Gi; Si, Ok-Ja; Park, Soo-Je; Yeon Hwang, Chung; Park, Jisoo; Lee, SangHoon; Rhee, Sung-Keun

    2016-01-01

    Polynyas are a key ecosystem for carbon cycling in the Antarctic Ocean due to the intensive primary production. Most of the knowledge regarding the bacterioplankton community in the Antarctic Ocean that is responsible for re-mineralization of fixed carbon comes from metagenomic analyses. Here, the extinction-dilution method was used to obtain representative heterotrophs from a polynya in the Amundsen Sea, Antarctica, and their biochemical potential for carbon re-mineralization were assessed. All 23 strains have close relatives belonging to type strains within the following genera (number of strains; % 16S rRNA gene sequence similarity): Bizionia (4; >97.8%), Leeuwenhoekiella (1; 96.2%), Pseudoalteromonas (14; >98.5%), Pseudomonas (1; 99.4%) and Sulfitobacter (3; 100%), which were also observed in 454 pyrosequencing-based analysis of 16S rRNA gene sequences of the polynya. Although sequence reads related to Polaribacter were the most common, Polaribacter strains could only be obtained from colonies cultured on agar plates. The strain of Leeuwenhoekiella showed a prominent ability in hydrolyzing diverse esters, amides, and glycosides while the strains of Pseudoalteromonas, Polaribacter, and Bizionia showed extracellular enzyme activities only on a narrow range of amides. The strains of Leeuwenhoekiella, Pseudoalteromonas, and Sulfitobacter utilized various labile carbon sources: carbohydrates, organic acids, amino acids, and peptides. The most frequent isolates, strains of Pseudoaltermonas, showed marked differences in terms of their potential to utilize different types of labile carbon sources, which may reflect high genomic diversity. The strains of Bizionia and Pseudomonas did not utilize carbohydrates. Unique biochemical properties associated with extracellular hydrolase activities and labile carbon utilization were revealed for dominant culturable heterotrophs which gives insights into their roles in active re-mineralization of fixed carbons in polynya.

  19. Interactions between marine snow and heterotrophic bacteria: aggregate formation and microbial dynamics

    DEFF Research Database (Denmark)

    Grossart, H.P.; Kiørboe, Thomas; Tang, K.W.

    2006-01-01

    Macroscopic aggregates (marine snow) contribute to new production and nutrient dynamics in the upper ocean and vertical fluxes of organic matter to the deep ocean. To test whether microorganisms play a significant role in phytoplankton aggregate formation we studied particle abundance and size...... and aggregation was studied by amplification of 16S rRNA gene fragments and denaturing gradient gel electrophoresis (DGGE). Our results show that the presence of bacteria was a prerequisite for aggregation of T. weissflogii but not of Navicula sp. Occurrences of distinct populations of free-living and attached...

  20. Biological and chemical factors driving the temporal distribution of cyanobacteria and heterotrophic bacteria in a eutrophic lake (West Lake, China).

    Science.gov (United States)

    Song, Hao; Xu, Jiahui; Lavoie, Michel; Fan, Xiaoji; Liu, Guangfu; Sun, Liwei; Fu, Zhengwei; Qian, Haifeng

    2017-02-01

    Physico-chemical parameters, hydrological conditions, and microbial interactions can affect the growth and persistence of cyanobacteria, but the interacting effects among these bloom-forming factors are still poorly known. This hampers our capacity to predict the occurrence of cyanobacterial bloom accurately. Here, we studied the relationship between temperature, N and P cycles, and the microbial community abundance and diversity at 0.5 m under the surface of West Lake (China) from January 21 to November 20, 2015, in order to better understand the key factors regulating temporal changes in the cyanobacterial community. Using high throughput sequencing of the 16S rRNA gene V3-V4 region, we studied the diversity and abundance of bacteria. In parallel, we measured physico-chemical parameters and followed the abundance of key genes involved in N fixation, denitrification, and nutrient uptake. Multivariate analyses suggest that P concentration and water temperature are the key factors controlling the outbreak of summer cyanobacterial bloom. RT-qPCR analyses of the bacterial community and measurements of the copy number of denitrification-related gene (nirK, nosZ, nirS) show that denitrification potential and denitrifying bacteria relative abundance (Pseudomonas and Bacillus) increased in concert with diazotrophic cyanobacterial genera (Anabaena, Nostoc, Aphanizomenon flos-aquae) and the common bloom-forming non-diazotrophic cyanobacterium genus Microcystis. The present study brings new insights on the complex interplay between physico-chemical parameters, heterotrophic bacterial community composition, nitrogen cycle, and cyanobacteria dominance in a eutrophic lake.

  1. Antagonistic interactions between filamentous heterotrophs and the cyanobacterium Nostoc muscorum.

    Science.gov (United States)

    Svercel, Miroslav; Saladin, Bianca; van Moorsel, Sofia J; Wolf, Sarah; Bagheri, Homayoun C

    2011-09-13

    Little is known about interactions between filamentous heterotrophs and filamentous cyanobacteria. Here, interactions between the filamentous heterotrophic bacteria Fibrella aestuarina (strain BUZ 2) and Fibrisoma limi (BUZ 3) with an axenic strain of the autotrophic filamentous cyanobacterium Nostoc muscorum (SAG 25.82) were studied in mixed cultures under nutrient rich (carbon source present in medium) and poor (carbon source absent in medium) conditions. F. aestuarina BUZ 2 significantly reduced the cyanobacterial population whereas F. limi BUZ 3 did not. Physical contact between heterotrophs and autotroph was observed and the cyanobacterial cells showed some level of damage and lysis. Therefore, either contact lysis or entrapment with production of extracellular compounds in close vicinity of host cells could be considered as potential modes of action.The supernatants from pure heterotrophic cultures did not have an effect on Nostoc cultures. However, supernatant from mixed cultures of BUZ 2 and Nostoc had a negative effect on cyanobacterial growth, indicating that the lytic compounds were only produced in the presence of Nostoc.The growth and survival of tested heterotrophs was enhanced by the presence of Nostoc or its metabolites, suggesting that the heterotrophs could utilize the autotrophs and its products as a nutrient source. However, the autotroph could withstand and out-compete the heterotrophs under nutrient poor conditions. Our results suggest that the nutrients in cultivation media, which boost or reduce the number of heterotrophs, were the important factor influencing the outcome of the interplay between filamentous heterotrophs and autotrophs. For better understanding of these interactions, additional research is needed. In particular, it is necessary to elucidate the mode of action for lysis by heterotrophs, and the possible defense mechanisms of the autotrophs.

  2. Antagonistic interactions between filamentous heterotrophs and the cyanobacterium Nostoc muscorum

    Directory of Open Access Journals (Sweden)

    Wolf Sarah

    2011-09-01

    Full Text Available Abstract Background Little is known about interactions between filamentous heterotrophs and filamentous cyanobacteria. Here, interactions between the filamentous heterotrophic bacteria Fibrella aestuarina (strain BUZ 2 and Fibrisoma limi (BUZ 3 with an axenic strain of the autotrophic filamentous cyanobacterium Nostoc muscorum (SAG 25.82 were studied in mixed cultures under nutrient rich (carbon source present in medium and poor (carbon source absent in medium conditions. Findings F. aestuarina BUZ 2 significantly reduced the cyanobacterial population whereas F. limi BUZ 3 did not. Physical contact between heterotrophs and autotroph was observed and the cyanobacterial cells showed some level of damage and lysis. Therefore, either contact lysis or entrapment with production of extracellular compounds in close vicinity of host cells could be considered as potential modes of action. The supernatants from pure heterotrophic cultures did not have an effect on Nostoc cultures. However, supernatant from mixed cultures of BUZ 2 and Nostoc had a negative effect on cyanobacterial growth, indicating that the lytic compounds were only produced in the presence of Nostoc. The growth and survival of tested heterotrophs was enhanced by the presence of Nostoc or its metabolites, suggesting that the heterotrophs could utilize the autotrophs and its products as a nutrient source. However, the autotroph could withstand and out-compete the heterotrophs under nutrient poor conditions. Conclusions Our results suggest that the nutrients in cultivation media, which boost or reduce the number of heterotrophs, were the important factor influencing the outcome of the interplay between filamentous heterotrophs and autotrophs. For better understanding of these interactions, additional research is needed. In particular, it is necessary to elucidate the mode of action for lysis by heterotrophs, and the possible defense mechanisms of the autotrophs.

  3. Hexavalent chromium reduction by aerobic heterotrophic bacteria indigenous to chromite mine overburden

    Directory of Open Access Journals (Sweden)

    Dey Satarupa

    2013-01-01

    Full Text Available Microbiological analysis of overburden samples collected from chromite mining areas of Orissa, India revealed that they are rich in microbial density as well as diversity and dominated by Gramnegative (58% bacteria. The phenotypically distinguishable bacterial isolates (130 showed wide degree of tolerance to chromium (2-8 mM when tested in peptone yeast extract glucose agar medium. Isolates (92 tolerating 2 mM chromium exhibited different degrees of Cr+6 reducing activity in chemically defined Vogel Bonner (VB broth and complex KSC medium. Three potent isolates, two belonging to Arthrobacter spp. and one to Pseudomonas sp. were able to reduce more than 50 and 80% of 2 mM chromium in defined and complex media respectively. Along with Cr+6 (MIC 8.6-17.8 mM, the isolates showed tolerance to Ni+2, Fe+3, Cu+2 and Co+2 but were extremely sensitive to Hg+2 followed by Cd+2, Mn+2 and Zn+2. In addition, they were resistant to antibiotics like penicillin, methicillin, ampicillin, neomycin and polymyxin B. During growth under shake-flask conditions, Arthrobacter SUK 1201 and SUK 1205 showed 100% reduction of 2 mM Cr+6 in KSC medium with simultaneous formation of insoluble precipitates of chromium salts. Both the isolates were also equally capable of completely reducing the Cr+6 present in mine seepage when grown in mine seepage supplemented with VB concentrate.

  4. 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...

  5. Ammonium removal of drinking water at low temperature by activated carbon filter biologically enhanced with heterotrophic nitrifying bacteria.

    Science.gov (United States)

    Qin, Wen; Li, Wei-Guang; Zhang, Duo-Ying; Huang, Xiao-Fei; Song, Yang

    2016-03-01

    We sought to confirm whether use of Acinetobacter strains Y7 and Y16, both strains of heterotrophic nitrifying bacteria, was practical for removing ammonium (NH4 (+)-N) from drinking water at low temperatures. To test this, ammonium-containing drinking water was treated with strains Y7 and Y16 at 8 and 2 °C. Continuous ammonium treatment was conducted in order to evaluate the performance of three biologically enhanced activated carbon (BEAC) filters in removing ammonium. The three BEAC filters were inoculated with strain Y7, strain Y16, and a mixture of strains Y7 and Y16, respectively. A granular activated carbon (GAC) filter, without inoculation by any strains, was tested in parallel with the BEAC filters as control. The results indicated that NH4 (+)-N removal was significant when a BEAC filter was inoculated with the mixture of strains Y7 and Y16 (BEAC-III filter). Amounts of 0.44 ± 0.05 and 0.25 ± 0.05 mg L(-1) NH4 (+)-N were removed using the BEAC-III filter at 8 and 2 °C, respectively. These values were 2.8-4.0-fold higher than the values of ammonium removal acquired using the GAC filter. The synergistic effect of using strains Y7 and Y16 in concert was the cause of the high-ammonium removal efficiency achieved by using the BEAC-III filter at low temperatures. In addition, a high C/N ratio may promote NH4 (+)-N removal efficiency by improving biomass and microbial activity. This study provides new insight into the use of biofilters to achieve biological removal of ammonium at low temperature.

  6. Seasonal seawater temperature as the major determinant for populations of culturable bacteria in the sediments of an intact mangrove in an arid region

    OpenAIRE

    2006-01-01

    Mangroves are highly productive marine ecosystems where bacteria (culturable and nonculturable) actively participate in biomineralization of organic matter and biotransformation of minerals. This study explores spatial and seasonal fluctuations of culturable heterotrophic bacteria and Vibrio spp. in the sediments of an intact mangrove ecosystem and determines the dominant environmental factors that govern these fluctuations. Sediment samples were collected monthly from three stations in the m...

  7. Signatures of Autotrophic and Heterotrophic Metabolic Activity in Enrichment Cultures from a Sulphur Oxidizing Acid Mine Site

    Science.gov (United States)

    Slater, G. F.; Bernier, L.; Cowie, B. R.; Warren, L. A.

    2006-12-01

    Delineating the role of microorganisms in geochemical processes of interest in natural environments requires the development of tools that provide the ability to distinguish amongst microbial activity associated with different metabolic guilds. The gap between phylogenetic characterization and phenotypic understanding remains, underscoring the need to consider alternative methods. Compound specific analysis of cellular components has the potential to differentiate between active metabolic processes supporting microbial communities and may be especially useful in extreme environments. The goal of this study was to determine whether the phospholipids fatty acid (PLFA) distribution and isotopic signatures associated with autotrophs and heterotrophs enriched from an acid mine drainage (AMD) system differed, and further whether natural consortial autotrophic isolates showed similar signatures to autotrophic pure strains of Acidithiobacillus ferrooxidans and A. thiooxidans. Two distinct initial enrichments with tetrathionate and CO2 yielded primarily autotrophic (95%) Acidithiobaccillus spp. sulphur oxidizing communities. The remaining microbial members of theses enrichments (subculture of the consortial isolates in a medium amended with glucose but without tetrathionate selectively resulted in their visible growth. PLFA profiles and δ13C signatures from autotrophic (1) natural enrichments, pure cultures of (2) A. ferrooxidans and (3) A. thiooxidans were similar, but collectively differed from those of the natural heterotrophic enrichment cultures. The PLFA profiles for the heterotrophic communities were made up of primarily (88-99%) C16:0 and two isomers of C18:1. In contrast, the autotrophic communities had high proportions of C16:1 (up to 18%) as well as cyclo C17 and cyclo C19 PLFA that combined comprised 18 to 58% of the observed PLFA. The δ13C signatures of the PLFA also differed strongly between the two trophic levels. The δ13C of the autotrophic PLFA, - 24 to

  8. Seasonal and spatial variations in heterotrophic nanoflagellate and bacteria abundances in sediments of a freshwater littoral zone

    NARCIS (Netherlands)

    Starink, Mathieu; Bär-Gilissen, M.J.; Cappenberg, T.E.

    1996-01-01

    We studied seasonal variation in heterotrophic nanoflagellates (HNAN) and bacterial, densities at different depths in the sediment of two freshwater littoral stations. Station 1 was in a reed bed of Phragmites australis; station 2 was outside the reed zone in open water. Benthic HNAN abundances

  9. Variation of a benthic heterotrophic bacteria community with different respiratory metabolisms in Coyuca de Benítez coastal lagoon (Guerrero, Mexico).

    Science.gov (United States)

    Ferrara-Guerrero, María Jesús; Castellanos-Páez, María Elena; Garza-Mouriño, Gabriela

    2007-03-01

    The fluctuations of the number, biomass and composition of the heterotrophic community were studied daily for two days, according to depth, pH, Eh, O2 and organic carbon concentration within a zone of the canal between the Coyuca de Benitez lagoon (Guerrero, Mexico) and the coastal waters. At the three moments of the day studied (6 am, 2 pm and 10 pm), the oxygen concentrations in the overlying water and in the superficial sediment layer were near air-saturation in the diurnal samplings (582 microM at 6 am and 665 microM at 2 pm), and sub-satured during the night (158 microM). In the sediments, the models of vertical distribution of Eh and organic carbon distributions were very irregular due to the bio-perturbation of the benthic, meio- and macrofauna, whose activity allows the superficial organic carbon to migrate towards sediment deeper layers. Vertical distribution of the different viable bacteria populations seems to be related to the hydrodynamic patterns of the communicating canal and sediments heterogeneity. In the sediment column, the heterotrophic bacteria total number varied from 6.8 to 20.3 x 108 cells cm(-3). The highest heterotrophic bacterial biomass values were encountered during the diurnal samplings (39.2 microgC.l(-1) at 6 am and 34.4 microgC.(l(-1) at 2 pm) and the lowest during the night (9.7 microgC.l(-1). The fluctuations of viable heterotrophic bacteria populations with different respiratory metabolisms (aerobic, microaerophilic and anaerobic) can be explained by the existence of suboxic microniches that appear when particles of sediment are resuspended due to the water circulation and the benthic infauna excavating activity, that allows the supernatant water oxygen to penetrate through its galleries towards deeper sediment zones. The statistical analysis (Multiple lineal regression model r2 > or = 0.5) showed that the on the whole, the hydrological parameters are not influence over the bacterial number and bacterial biomass distribution (r2

  10. Optimization of culture media for large-scale lutein production by heterotrophic Chlorella vulgaris.

    Science.gov (United States)

    Jeon, Jin Young; Kwon, Ji-Sue; Kang, Soon Tae; Kim, Bo-Ra; Jung, Yuchul; Han, Jae Gap; Park, Joon Hyun; Hwang, Jae Kwan

    2014-01-01

    Lutein is a carotenoid with a purported role in protecting eyes from oxidative stress, particularly the high-energy photons of blue light. Statistical optimization was performed to growth media that supports a higher production of lutein by heterotrophically cultivated Chlorella vulgaris. The effect of media composition of C. vulgaris on lutein was examined using fractional factorial design (FFD) and central composite design (CCD). The results indicated that the presence of magnesium sulfate, EDTA-2Na, and trace metal solution significantly affected lutein production. The optimum concentrations for lutein production were found to be 0.34 g/L, 0.06 g/L, and 0.4 mL/L for MgSO4 ·7H2 O, EDTA-2Na, and trace metal solution, respectively. These values were validated using a 5-L jar fermenter. Lutein concentration was increased by almost 80% (139.64 ± 12.88 mg/L to 252.75 ± 12.92 mg/L) after 4 days. Moreover, the lutein concentration was not reduced as the cultivation was scaled up to 25,000 L (260.55 ± 3.23 mg/L) and 240,000 L (263.13 ± 2.72 mg/L). These observations suggest C. vulgaris as a potential lutein source.

  11. Seasonal seawater temperature as the major determinant for populations of culturable bacteria in the sediments of an intact mangrove in an arid region.

    Science.gov (United States)

    Gonzalez-Acosta, Barbara; Bashan, Yoav; Hernandez-Saavedra, Norma Y; Ascencio, Felipe; Cruz-Agüero, Gustavo

    2006-02-01

    Mangroves are highly productive marine ecosystems where bacteria (culturable and non-culturable) actively participate in biomineralization of organic matter and biotransformation of minerals. This study explores spatial and seasonal fluctuations of culturable heterotrophic bacteria and Vibrio spp. in the sediments of an intact mangrove ecosystem and determines the dominant environmental factors that govern these fluctuations. Sediment samples were collected monthly from three stations in the mangroves of Laguna de Balandra, Baja California Sur, Mexico, through an annual cycle. Physicochemical parameters included seawater temperature, salinity, and concentration of dissolved oxygen. Viable counts of culturable heterotrophic bacteria and Vibrio spp. were made. In one sample (March 2003), nutrient concentrations (ammonium, nitrites, nitrates, and phosphates), organic matter, pH and sediment texture were also determined. General cluster analyses, analysis of variance of specific variables, and several principal component analyses demonstrated that seawater temperature is the principal determinant of seasonal distribution of culturable heterotrophic bacteria and Vibrio spp. in mangrove sediments. Soil texture, concentration of nutrients, and organic matter concentration contribute to heterogenicity to a lesser extent. A large spatial variation in bacterial populations was observed over short distances ( approximately 1 m) in sampling areas within the same site. These analyses show that the culturable bacterial distribution in sediments of mangroves has high spatial and temporal heterogeneity.

  12. The effect of Chlorella growth and inorganic nutrients absorption by marine heterotrophic bacteria%海洋异养细菌对小球藻生长和无机营养盐吸收的影响研究

    Institute of Scientific and Technical Information of China (English)

    白洁; 易齐涛; 李佳霖

    2009-01-01

    The consortium of marine heterotrophic bacteria and Chlorella vulgaris was separated and six strains of bacteria were isolated,purified and analyzed by the DNA fingerprint of DGGE(denature gel gradient electrophoresis).One of the strains was found to promote the growth of the C.vulgaris,while the other five strains had no effects.Meanwhile,all of the separated strains could be observed to grow well on the DOC from the pure culture.Compared with the pure culture of C.vulgaris,the mixed culture of the consortium was observed a more efficiency of removing inorganic nitrogen.Also,the absorption of inorganic nutrients was considerably made by bacteria.%从胶州湾海洋异养细菌同小球藻(Chlorella vulgaris)的共存体系中,分离出6株形态特征差异较大的异养细菌,并做变性凝胶梯度电泳(Denature Gel Gradient Electrophoresis,DGGE)分析.其中一株对小球藻的生长有较大的促进作用,而其余菌株则没有明显的效果.6株细菌能在小球藻产生的胞外溶解有机物(Dissolved Organic Mate rials,DOM)溶液中生长良好,共存细菌对提高菌藻体系对无机营养盐的吸收具有较大的贡献.

  13. A decadal (2002-2014 analysis for dynamics of heterotrophic bacteria in an Antarctic coastal ecosystem: variability and physical and biogeochemical forcings

    Directory of Open Access Journals (Sweden)

    Hyewon Kim

    2016-11-01

    Full Text Available We investigated the dynamics of heterotrophic bacteria in the coastal western Antarctic Peninsula (WAP, using decadal (2002-2014 time series of two bacterial variables, bacterial production (BP via 3H-leucine incorporation rates and bacterial biomass (BB via bacterial abundance, collected at Palmer Antarctica Long Term Ecological Research (LTER Station B (64.8°S, 64.1°W over a full austral growing season (October-March. Strong seasonal and interannual variability in the degree of bacterial coupling with phytoplankton processes were observed with varying lags. On average, BP was only 4% of primary production (PP, consistent with low BP:PP ratios observed in polar waters. BP was more strongly correlated with chlorophyll (Chl, than with PP, implying that bacteria feed on DOC produced from a variety of trophic levels (e.g. zooplankton sloppy feeding and excretion as well as directly on phytoplankton-derived DOC. The degree of bottom-up control on bacterial abundance was moderate and relatively consistent across entire growing seasons, suggesting that bacteria in the coastal WAP are under consistent DOC limitation. Temperature also influenced BP rates, though its effect was weaker than DOC. We established generalized linear models (GLMs for monthly composites of BP and BB via stepwise regression to explore a set of physical and biogeochemical predictors. Physically, high BP and large BB were shaped by a stratified water-column, similar to forcing mechanisms favoring phytoplankton blooms, but high sea surface temperature (SST also significantly promoted bacterial processes. High BP and large BB were influenced by high PP and bulk DOC concentrations. Based on these findings, we suggest an increasingly important role of marine heterotrophic bacteria in the coastal WAP food-web as climate change introduces a more favorable environmental setting for promoting BP, with increased DOC from retreating glaciers, a more stabilized upper water-column from ice

  14. Influence of river discharge on abundance and dissemination of heterotrophic, indicator and pathogenic bacteria along the east coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Prasad, V.R.; Srinivas, T.N.R.; Sarma, V.V.S.S.

    and pathogenic bacteria, has a vital position in marine pollution studies, as this gives an unswerving consequence of pollution on human health and also other marine biota. Hence it is crucial to observe microbial load in marine environments to warrant... of marine resources that pose a human health hazard and subsequent economic loss. Higher abundance of different bacteria was observed off Visakhapatnam city due to the intensive anthropogenic activities. Besides highlighting significant correlations...

  15. 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.

  16. Calcium carbonate precipitation by heterotrophic bacteria isolated from biofilms formed on deteriorated ignimbrite stones: influence of calcium on EPS production and biofilm formation by these isolates.

    Science.gov (United States)

    López-Moreno, Angélica; Sepúlveda-Sánchez, José David; Mercedes Alonso Guzmán, Elia Mercedes; Le Borgne, Sylvie

    2014-01-01

    Heterotrophic CaCO3-precipitating bacteria were isolated from biofilms on deteriorated ignimbrites, siliceous acidic rocks, from Morelia Cathedral (Mexico) and identified as Enterobacter cancerogenus (22e), Bacillus sp. (32a) and Bacillus subtilis (52g). In solid medium, 22e and 32a precipitated calcite and vaterite while 52g produced calcite. Urease activity was detected in these isolates and CaCO3 precipitation increased in the presence of urea in the liquid medium. In the presence of calcium, EPS production decreased in 22e and 32a and increased in 52g. Under laboratory conditions, ignimbrite colonization by these isolates only occurred in the presence of calcium and no CaCO3 was precipitated. Calcium may therefore be important for biofilm formation on stones. The importance of the type of stone, here a siliceous stone, on biological colonization is emphasized. This calcium effect has not been reported on calcareous materials. The importance of the effect of calcium on EPS production and biofilm formation is discussed in relation to other applications of CaCO3 precipitation by bacteria.

  17. Isolation and phylogenetic characterization of iron-sulfur-oxidizing heterotrophic bacteria indigenous to nickel laterite ores of Sulawesi, Indonesia: Implications for biohydrometallurgy

    Science.gov (United States)

    Chaerun, Siti Khodijah; Hung, Sutina; Mubarok, Mohammad Zaki; Sanwani, Edy

    2015-09-01

    The main objective of this study was to isolate and phylogenetically identify the indigenous iron-sulfur-oxidizing heterotrophic bacteria capable of bioleaching nickel from laterite mineral ores. The bacteria were isolated from a nickel laterite mine area in South Sulawesi Province, Indonesia. Seven bacterial strains were successfully isolated from laterite mineral ores (strains SKC/S-1 to SKC/S-7) and they were capable of bioleaching of nickel from saprolite and limonite ores. Using EzTaxon-e database, the 16S rRNA gene sequences of the seven bacterial strains were subjected to phylogenetic analysis, resulting in a complete hierarchical classification system, and they were identified as Pseudomonas taiwanensis BCRC 17751 (98.59% similarity), Bacillus subtilis subsp. inaquosorum BGSC 3A28 (99.14% and 99.32% similarities), Paenibacillus pasadenensis SAFN-007 (98.95% and 99.33% similarities), Bacillus methylotrophicus CBMB 205 (99.37% similarity), and Bacillus altitudinis 41KF2b (99.37% similarity). It is noteworthy that members of the phylum Firmicutes (in particular the genus Bacillus) predominated in this study, therefore making them to have the high potential to be candidates for the bioleaching of nickel from laterite mineral ores. To our knowledge, this is the first report on the predominance of the phylum Firmicutes in the Sulawesi laterite mineral ores.

  18. Phytoplankton, Bacteria and Heterotrophic Nanoflagellate studies using ship and OCM-2 data along a coastal transect in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Matondkar, S.G.P.; Basu, S.; Parab, S.G.; Pednekar, S.; Niyati Hede, N.; Dwivedi, R.M.; Raman, M.; Babu, K.N.; Shukla, A.K.; Shirdhankar, M.M.

    . Chlorophyll a (Chl a) values of the coastal waters were much higher than shelf stations. The total bacteria of coastal waters ranged from 0.93x109 - 4.359x109 cells L sup(-1). A strong positive correlation was noticed in Chl a and bacterial load, especially...

  19. Diversity and bioactive potentials of culturable heterotrophic bacteria from the surficial sediments of the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Anas, A.; Nilayangod, C.; Jasmin, C.; Vinothkumar, S.; Parameswaran, P.S.; Nair, S.

    . BMC Bioinform 12:385 Pai SS et al (2010) Penaeus monodon larvae can be protected from Vibrio harveyi infection by pre-emptive treatment of a rearing system with antagonistic or non-antagonistic bacterial probiotics. Aquac Res 41:847–860 Paulmier A...). Preparation of organic extracts Organic extract of 131 isolates was prepared using ethyl acetate as solvent. Bacterial isolates for the production of secondary metabolites were prepared in basal medium. Briefly, 100 ll of bacterial inoculum (1.0 OD at 600 nm...

  20. Abiotic process for Fe(II) oxidation and green rust mineralization driven by a heterotrophic nitrate reducing bacteria (Klebsiella mobilis).

    Science.gov (United States)

    Etique, Marjorie; Jorand, Frédéric P A; Zegeye, Asfaw; Grégoire, Brian; Despas, Christelle; Ruby, Christian

    2014-04-01

    Green rusts (GRs) are mixed Fe(II)-Fe(III) hydroxides with a high reactivity toward organic and inorganic pollutants. GRs can be produced from ferric reducing or ferrous oxidizing bacterial activities. In this study, we investigated the capability of Klebsiella mobilis to produce iron minerals in the presence of nitrate and ferrous iron. This bacterium is well-known to reduce nitrate using an organic carbon source as electron donor but is unable to enzymatically oxidize Fe(II) species. During incubation, GR formation occurred as a secondary iron mineral precipitating on cell surfaces, resulting from Fe(II) oxidation by nitrite produced via bacterial respiration of nitrate. For the first time, we demonstrate GR formation by indirect microbial oxidation of Fe(II) (i.e., a combination of biotic/abiotic processes). These results therefore suggest that nitrate-reducing bacteria can potentially contribute to the formation of GR in natural environments. In addition, the chemical reduction of nitrite to ammonium by GR is observed, which gradually turns the GR into the end-product goethite. The nitrogen mass-balance clearly demonstrates that the total amount of ammonium produced corresponds to the quantity of bioreduced nitrate. These findings demonstrate how the activity of nitrate-reducing bacteria in ferrous environments may provide a direct link between the biogeochemical cycles of nitrogen and iron.

  1. Variation of a benthic heterotrophic bacteria community with different respiratory metabolisms in Coyuca de Benítez coastal lagoon (Guerrero, Mexico

    Directory of Open Access Journals (Sweden)

    María Jesús Ferrara-Guerrero

    2007-03-01

    Full Text Available The fluctuations of the number, biomass and composition of the heterotrophic community were studied daily for two days, according to depth, pH, Eh, O2 and organic carbon concentration within a zone of the canal between the Coyuca de Benítez lagoon (Guerrero, Mexico and the coastal waters. At the three moments of the day studied (6 am, 2 pm and 10 pm, the oxygen concentrations in the overlying water and in the superficial sediment layer were near air-saturation in the diurnal samplings (582 µM at 6 am and 665 µM at 2 pm, and sub-satured during the night (158 µM. In the sediments, the models of vertical distribution of Eh and organic carbon distributions were very irregular due to the bio-perturbation of the benthic, meio- and macrofauna, whose activity allows the superficial organic carbon to migrate towards sediment deeper layers. Vertical distribution of the different viable bacteria populations seems to be related to the hydrodynamic patterns of the communicating canal and sediments heterogeneity. In the sediment column, the heterotrophic bacteria total number varied from 6.8 to 20.3 x 108 cells cm-3. The highest heterotrophic bacterial biomass values were encountered during the diurnal samplings (39.2 µgC.l-1 at 6 am and 34.4 µgC.l-1 at 2 pm and the lowest during the night (9.7 µgC.l-1. The fluctuations of viable heterotrophic bacteria populations with different respiratory metabolisms (aerobic, microaerophilic and anaerobic can be explained by the existence of suboxic microniches that appear when particles of sediment are resuspended due to the water circulation and the benthic infauna excavating activity, that allows the supernatant water oxygen to penetrate through its galleries towards deeper sediment zones. The statistical analysis (Multiple lineal regression model r²≥ 0.5 showed that the on the whole, the hydrological parameters are not influence over the bacterial number and bacterial biomass distribution (r²≤ 0

  2. Habitat and taxon as driving forces of carbohydrate catabolism in marine heterotrophic bacteria: example of the model algae-associated bacterium Zobellia galactanivorans Dsij(T).

    Science.gov (United States)

    Barbeyron, Tristan; Thomas, François; Barbe, Valérie; Teeling, Hanno; Schenowitz, Chantal; Dossat, Carole; Goesmann, Alexander; Leblanc, Catherine; Oliver Glöckner, Frank; Czjzek, Mirjam; Amann, Rudolf; Michel, Gurvan

    2016-12-01

    The marine flavobacterium Zobellia galactanivorans Dsij(T) was isolated from a red alga and by now constitutes a model for studying algal polysaccharide bioconversions. We present an in-depth analysis of its complete genome and link it to physiological traits. Z. galactanivorans exhibited the highest gene numbers for glycoside hydrolases, polysaccharide lyases and carbohydrate esterases and the second highest sulfatase gene number in a comparison to 125 other marine heterotrophic bacteria (MHB) genomes. Its genome contains 50 polysaccharide utilization loci, 22 of which contain sulfatase genes. Catabolic profiling confirmed a pronounced capacity for using algal polysaccharides and degradation of most polysaccharides could be linked to dedicated genes. Physiological and biochemical tests revealed that Z. galactanivorans stores and recycles glycogen, despite loss of several classic glycogen-related genes. Similar gene losses were observed in most Flavobacteriia, suggesting presence of an atypical glycogen metabolism in this class. Z. galactanivorans features numerous adaptive traits for algae-associated life, such as consumption of seaweed exudates, iodine metabolism and methylotrophy, indicating that this bacterium is well equipped to form profitable, stable interactions with macroalgae. Finally, using statistical and clustering analyses of the MHB genomes we show that their carbohydrate catabolism correlates with both taxonomy and habitat. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  3. Culturable bacteria in Himalayan ice in response to atmospheric circulation

    Directory of Open Access Journals (Sweden)

    S. Zhang

    2006-06-01

    Full Text Available Only recently has specific attention been given to culturable bacteria in Tibetan glaciers, but their relation to atmospheric circulation is less understood yet. Here we investigate the seasonal variation of culturable bacteria preserved in a Himalayan ice core. High concentration of culturable bacteria in glacial ice deposited during the pre-monsoon season is attributed to the transportation of continental dust stirred up by the frequent dust storms in Northwest China during spring. This is also confirmed by the spatial distribution of culturable bacteria in Tibetan glaciers. Culturable bacteria deposited during monsoon season are more diverse than other seasons because they derive from both marine air masses and local or regional continental sources. We suggest that microorganisms in Himalayan ice can be used to reconstruct atmospheric circulation.

  4. Monitoring and spatial distribution of heterotrophic bacteria and fecal coliforms in the Rodrigo de Freitas Lagoon, Rio de Janeiro, Brazil

    Directory of Open Access Journals (Sweden)

    Lutterbach Márcia T. S.

    2001-01-01

    Full Text Available The distribution of heterothrophic bacteria and fecal coliforms was monitored at four sampling stations located near the shore of the Rodrigo de Freitas Lagoon, in the city of Rio de Janeiro, Brazil. Water samples were collected, monthly from October 1994 through September 1998. The highest heterothrophic count (6.5x10 7 CFU/100mL was recorded at stations 2 and 4 during August 1998 and the lowest (10 ³ CFU/100 mL at station 3 during February 1995. With respect to fecal coliforms, the highest and lowest counts were 1.6x10 5 coliforms/100mL at station 3 during March 1997 and <1 coliform/100mL at all the stations during February 1995 and September 1997 as well as station 3 during February 1998. The data indicated a percentage increase of the microorganisms surveyed over time at all the sampling stations studied.

  5. Feeding by the heterotrophic dinoflagellate Oxyrrhis marina on the red-tide raphidophyte Heterosigma akashiwo: a potential biological method to control red tides using mass-cultured grazers.

    Science.gov (United States)

    Jeong, Hae Jin; Kim, Jae Seong; Yoo, Yeong Du; Kim, Seong Taek; Kim, Tae Hoon; Park, Myung Gil; Lee, Chang Hoon; Seong, Kyeong Ah; Kang, Nam Seon; Shim, Jae Hyung

    2003-01-01

    As part of the development of a method to control the outbreak and persistence of red tides using mass-cultured heterotrophic protist grazers, we measured the growth and ingestion rates of cultured Oxyrrhis marina (a heterotrophic dinoflagellate) on cultured Heterosigma akashiwo (a raphidophyte) in bottles in the laboratory and in mesocosms (ca. 60 liter) in nature, and those of the cultured grazer on natural populations of the red-tide organism in mesocosms set up in nature. In the bottle incubation, specific growth rates of O. marina increased rapidly with increasing concentration of cultured prey up to ca. 950 ng C ml(-1) (equivalent to 9,500 cells ml(-1)), but were saturated at higher concentrations. Maximum specific growth rate (mumax), KGR (prey concentration sustaining 0.5 mumax) and threshold prey concentration of O. marina on H. akashiwo were 1.43 d(-1), 104 ng C ml(-1), and 8.0 ng C ml(-1), respectively. Maximum ingestion and clearance rates of O. marina were 1.27 ng C grazer(-1) d(-1) and 0.3 microl grazer(-1) h(-1), respectively. Cultured O. marina grew well effectively reducing cultured and natural populations of H. akashiwo down to a very low concentration within 3 d in the mesocosms. The growth and ingestion rates of cultured O. marina on natural populations of H. akashiwo in the mesocosms were 39% and 40%, respectively, of those calculated based on the results from the bottle incubation in the laboratory, while growth and ingestion rates of cultured O. marina on cultured H. akashiwo in the mesocosms were 55% and 36%, respectively. Calculated grazing impact by O. marina on natural populations of H. akashiwo suggests that O. marina cultured on a large scale could be used for controlling red tides by H. akashiwo near aquaculture farms that are located in small ponds, lagoons, semi-enclosed bays, and large land-aqua tanks to which fresh seawater should be frequently supplied.

  6. Comparison of Optimal Thermodynamic Models of the Tricarboxylic Acid Cycle from Heterotrophs, Cyanobacteria, and Green Sulfur Bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Dennis G.; Jaramillo Riveri, Sebastian I.; Baxter, Douglas J.; Cannon, William R.

    2014-12-15

    We have applied a new stochastic simulation approach to predict the metabolite levels, energy flow, and material flux in the different oxidative TCA cycles found in E. coli and Synechococcus sp. PCC 7002, and in the reductive TCA cycle typical of chemolithoautotrophs and phototrophic green sulfur bacteria such as Chlorobaculum tepidum. The simulation approach is based on equations of state and employs an assumption similar to that used in transition state theory. The ability to evaluate the thermodynamics of metabolic pathways allows one to understand the relationship between coupling of energy and material gradients in the environment and the selforganization of stable biological systems, and it is shown that each cycle operates in the direction expected due to its environmental niche. The simulations predict changes in metabolite levels and flux in response to changes in cofactor concentrations that would be hard to predict without an elaborate model based on the law of mass action. In fact, we show that a thermodynamically unfavorable reaction can still have flux in the forward direction when it is part of a reaction network. The ability to predict metabolite levels, energy flow and material flux should be significant for understanding the dynamics of natural systems and for understanding principles for engineering organisms for production of specialty chemicals, such as biofuels.

  7. Effects of biofloc promotion on water quality, growth, biomass yield and heterotrophic community in Litopenaeus vannamei (Boone, 1931) experimental intensive cultures

    OpenAIRE

    Irasema E. Luis-Villaseñor; Domenico Voltolina; Juan M. Audelo-Naranjo; María R. Pacheco-Marges; Víctor E. Herrera-Espericueta; Emilio Romero-Beltrán

    2015-01-01

    Six 1.2-m3 tanks were stocked with an initial biomass of 500 g m-3 of Litopenaeus vannamei juveniles (individual weight: 1.0±0.3 g), to evaluate the effect of biofloc promotion on water quality and on shrimp growth and production, and to identify the dominant taxa in the heterotrophic communities present in experimental closed cultures. Feeding was ad libitum twice daily with 35% protein shrimp feed. Three tanks were managed as biofloc technology (BFT) systems, adding daily an amount of cornm...

  8. Influence factors on growth of heterotrophic bacteria in water using PESA as water treatment agent%使用聚环氧琥珀酸水处理剂时水中异养菌繁殖的影响因素

    Institute of Scientific and Technical Information of China (English)

    傅晓萍; 李本高; 刘小平

    2011-01-01

    采用微生物培养菌落计数法研究了使用聚环氧琥珀酸水处理剂时水中PESA,磷、通气量,初始茵数及pH值对异养菌繁殖的影响,结果表明:PESA使用浓度较低时对异养菌繁殖影响较小,浓度增加促进异养菌生长期繁殖;磷酸盐促进异养菌稳定期繁殖;通气对异养菌生长繁殖影响不明显;初始菌数对异养菌繁殖的稳定期影响不明显;pH值对异养菌的生长繁殖影响较大.%The effects of polyepoxysuccinic acid ( PESA ), phosphorus, ventilation, initial amount of heterotrophic bacteria and pH value on the growth of heterotrophic bacteria in the water using PESA as a water treatment agent were studied by the flat-dish numeration method. The results showed that PESA had little influence on the breeding of heterotrophic bacteria at a low concentration, while it promoted the growth rate of heterotrophic bacteria as its concentration increased. The higher the concentration of phosphate, the more the amount of heterotrophic bacteria in the stable breeding period.Ventilation had no effect on the growth of heterotrophic bacteria. The initial amount of heterotrophic bacteria had little influence on the amount during the balance period. The pH value had a significant impact on the breeding of heterotrophic bacteria.

  9. 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...

  10. Biodegradation of endosulfan by mixed bacteria culture strains of ...

    African Journals Online (AJOL)

    Biodegradation of endosulfan by mixed bacteria culture strains of Pseudomonas ... PROMOTING ACCESS TO AFRICAN RESEARCH ... The biodegradation process was carried out according to the method established by Buff et al., 1992.

  11. Elective culture of bacteria used in bioleaching on pyrrhotite

    Institute of Scientific and Technical Information of China (English)

    邱冠周; 覃文庆; 蓝卓越; 黎维中

    2003-01-01

    Elective culture of bacteria on pyrrhotite was researched, and the selected bacteria were tested on bi-oleaching of marmatite and zinc sulfide ore. The results show that the microorganism cultured on pyrrhotite with va-rious S/Fe ratios is a mixed culture of thiobacillus ferrooxidans and thiobacillus thiooxidans, of which the integral ac-tivity and the oxidation capability of Fe2+ and S are enhanced. With the high Fe and low S content of pyrrhotite, the oxida-tion capacity of ferrous ion is improved; on the contrary, the oxidation capacity of sulfur is advanced. The bioleaching ca-pacity of bacteria cultured on marmatite is better than that of the bacteria cultivated by conventional methods.

  12. Effects of culture conditions on acetic acid production by bacteria ...

    African Journals Online (AJOL)

    SARAH

    2015-11-30

    Nov 30, 2015 ... Keywords: Acetic acid bacteria, acetic acid production, Cocoa fermentation, culture conditions. INTRODUCTION ... assessed by acid forming colony characterized by a ... production capacity to ethanol, lactic acid, acetic acid.

  13. An analysis of the changes in soluble hydrogenase and global gene expression in Cupriavidus necator (Ralstonia eutropha) H16 grown in heterotrophic diauxic batch culture.

    Science.gov (United States)

    Jugder, Bat-Erdene; Chen, Zhiliang; Ping, Darren Tan Tek; Lebhar, Helene; Welch, Jeffrey; Marquis, Christopher P

    2015-03-25

    Soluble hydrogenases (SH) are enzymes that catalyse the oxidation of molecular hydrogen. The SH enzyme from Cupriavidus necator H16 is relatively oxygen tolerant and makes an attractive target for potential application in biochemical hydrogen fuel cells. Expression of the enzyme can be mediated by derepression of the hox promoter system under heterotrophic conditions. However, the overall impact of hox derepression, from a transcriptomic perspective, has never been previously reported. Derepression of hydrogenase gene expression upon fructose depletion was confirmed in replicate experiments. Using qRT-PCR, hoxF was 4.6-fold up-regulated, hypF2 was up-regulated in the cells grown 2.2-fold and the regulatory gene hoxA was up-regulated by a mean factor of 4.5. A full transcriptomic evaluation revealed a substantial shift in the global pattern of gene expression. In addition to up-regulation of genes associated with hydrogenase expression, significant changes were observed in genes associated with energy transduction, amino acid metabolism, transcription and translation (and regulation thereof), genes associated with cell stress, lipid and cell wall biogenesis and other functions, including cell motility. We report the first full transcriptome analysis of C. necator H16 grown heterotrophically on fructose and glycerol in diauxic batch culture, which permits expression of soluble hydrogenase under heterotrophic conditions. The data presented deepens our understanding of the changes in global gene expression patterns that occur during the switch to growth on glycerol and suggests that energy deficit is a key driver for induction of hydrogenase expression in this organism.

  14. Nitrate and sulfate reducers-retrievable number of bacteria and their activities in Indian waters

    Digital Repository Service at National Institute of Oceanography (India)

    LokaBharathi, P.A.; Nair, S.; Chandramohan, D.

    Culturable heterotrophic, nitrate reducing and sulfate reducing bacteria (HB, NRB and SRB) were enumerated from 25, 50, 100 and 200 m depths at 15 stations and their potential activities viz. Nitrate reducing (NRA) and Sulfate reducing (SRA) were...

  15. "DRUG RESISTANCE PATTERN IN ISOLATED BACTERIA FROM BLOOD CULTURES"

    OpenAIRE

    A Sobhani; H. Shodjai S. Javanbakht

    2004-01-01

    Bacteremia is an important infectious disease which may lead to death. Common bacteria and pattern of antibiotic resistance in different communities are different and understanding these differences is important. In the present study, relative frequency and pattern of drug resistance have been examined in bacteria isolated from blood cultures in Razi Hospital laboratory. The method of the study was descriptive. Data collection was carried out retrospectively. Total sample consisted of 311 pos...

  16. 黄河三角洲南部潮间带底栖异样细菌的分布特征研究%DISTRIBUTION OF HETEROTROPHIC BACTERIA IN SEDIMENTS IN THE SOUTHERN INTERTIDAL AREA OF YELLOW RIVER DELTA

    Institute of Scientific and Technical Information of China (English)

    张鹏; 邹立; 姚晓; 山口一岩; 郭新宇; 高会旺

    2011-01-01

    2008年4月和7月于黄河三角洲南部潮间带进行了大面站调查,采用DAPI荧光染色荧光显微镜计数法测定了沉积物中异养细菌数量,研究其分布特征,探讨满足其生长繁殖需要的物质来源.结果表明,春季和夏季潮间带沉积物中异养细菌丰度的变化范围分别为4.0~31.9×105 cells/g dw(平均值为11.81×105 cells/g dw)和5.9~53.5×105 cells/g dw(平均值为17.80×105cells/g dw).与世界其它地区相比,本调查区域沉积物中异养细菌丰度处于较低水平,这可能与该区域沉积物中POC含量较低有关(春季平均为0.10%,夏季平均为0.57%).春季和夏季沉积物中BB:PB(Bacteria Biomass,BB;Phytoplankton Biomass,PB)值的变化范围分别为0.02~0.89%(平均为0.26%)和0.09~3.38%(平均为0.55%),都处于较低水平(<5%);该较低水平表明底栖藻类现存量远远超过了异养细茵生长的需求.春季和夏季潮间带沉积物中异养细菌丰度和叶绿素浓度的相关系数均为0.24,显示出不显著相关,说明藻类有机物不是异养细菌食物的主要来源.本研究区域有多条河流输入,沉积物中的异养细菌生长繁殖所需的溶解有机物可能有相当一部分来自陆源径流.%In order to study on the distribution of heterotrophic bacteria in sediments in the southern intertidal area of Yellow River Delta, explore the material supplying for their growth and production, heterotrophic bacteria in sediments were analyzed in April and July 2008, stained with DAPI and counted with fluorescence microscopy. The results showed that the heterotrophic bacteria abundance in sediments ranged at 4. 0~31.9 × 105 cells/g dw (averaged at 11.81× 10s cells/g dw) and 5.9~53. 5 × 105 cells/g dw (averaged at 17.80 × 105 cells/g dw) in spring and summer, respectively. Compared to other similar areas all over the world, the heterotrophic bacteria abundance in this area was at a relatively low level. This may be due to the

  17. Isolation and Characterization of a New Heterotrophic Nitrifying Bacillus sp. Strain

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective To characterize the heterotrophic nitrifying bacteria. Methods The bacteria were isolated from membrane bioreactor for treating synthetic wastewater using the method newly introduced in this study. Fluorescence in situ hybridization (FISH) was used to validate the nonexistence of autotrophic ammonia oxidizers and nitrite oxidizers. Batch tests were carried out to investigate the capability of heterotrophic nitrification by the pure culture. Phylogenetic analysis of the pure culture was performed. Results A heterotrophic nitrifier, named Bacillus sp. LY, was newly isolated from the membrane bioreactor system in which the efficiency of TN removal was up to 80%. After 24-day, incubation, the removal efficiency of COD by Bacillus sp. LYwas 71.7%. The ammonium nitrogen removal rate after assimilation nearly ceased by Bacillus sp. LYwas 74.7%.The phylogenetic tree of Bacillus sp. LY and the neighbouring nitrifiers were given. Conclusions The batch test results indicate that Bacillus sp. LY can utilize the organic carbon as the source of assimilation when it grows on glucose and ammonium chloride medium accompanying the formation of oxidized-nitrogen. It also can denitrify nitrate while nitrifying. Bacillus sp. LY may become a new bacterial resource for heterotrophic nitrification and play a bioremediation role in nutrient removal.

  18. Variation of a benthic heterotrophic bacteria community with different respiratory metabolisms in Coyuca de Benítez coastal lagoon (Guerrero, Mexico)

    OpenAIRE

    Jesús Ferrara Guerrero, María; Elena Castellanos Páez, María; Garza Mouriño, Gabriela

    2003-01-01

    The fluctuations of the number, biomass and composition of the heterotrophic community were studied daily for two days, according to depth, pH, Eh, O2 and organic carbon concentration within a zone of the canal between the Coyuca de Benítez lagoon (Guerrero, Mexico) and the coastal waters. At the three moments of the day studied (6 am, 2 pm and 10 pm), the oxygen concentrations in the overlying water and in the superficial sediment layer were near air-saturation in the diurnal samplings (582 ...

  19. Variation of a benthic heterotrophic bacteria community with different respiratory metabolisms in Coyuca de Benítez coastal lagoon (Guerrero, México)

    OpenAIRE

    María Jesús Ferrara-Guerrero; María Elena Castellanos-Páez; Gabriela Garza-Mouriño

    2007-01-01

    The fluctuations of the number, biomass and composition of the heterotrophic community were studied daily for two days, according to depth, pH, Eh, O2 and organic carbon concentration within a zone of the canal between the Coyuca de Benítez lagoon (Guerrero, Mexico) and the coastal waters. At the three moments of the day studied (6 am, 2 pm and 10 pm), the oxygen concentrations in the overlying water and in the superficial sediment layer were near air-saturation in the diurnal samplings (582 ...

  20. 低温异养硝化菌的鉴定及对小白鼠的安全性研究%Study on Identify of Low Temperature Heterotrophic Nitvification Bacteria and Safety of ICR Rats

    Institute of Scientific and Technical Information of China (English)

    黄晓飞; 李伟光; 张多英; 潘忠诚; 秦雯; 宿程远

    2012-01-01

    对一株在低温环境中具有较强硝化能力的异养硝化菌经菌落特征观察、革兰氏染色镜检和生化特性进行研究,鉴定该菌为不动杆菌属(Acinetobacter.)成员.同时通过持续饲喂法和腹腔注射法对小白鼠进行安全性试验,结果:通过腹腔注射途径确定的半数致死量LD(50)为5.41×1011 CFU/kg;经口服途径持续饲喂3个月低温异养硝化菌(Acinetobacter.Y20) 1.5×1012 CFU/kg体重以下是安全的,从而表明该菌对哺乳动物是安全的.%In this paper, a strain in low temperature environment with strong nitrification capacity by the colony characteristics of heterotrophic nitrification bacteria, Gram staining and biochemical characteristics were studied, the identification of the bacterium Acinetobacter species ( Acinetobacter. ) members. At the same time through continuous feeding method and intraperitoneal injection on mice for safety tests, results: through intraperitoneal injection of pathways that determine the half lethal dose of LD ( 50) to 5.41 ×101lCFU/kg; by the oral route continued feeding of low temperature for 3 months of heterotrophic nitrification bacteria ( Acinetobacter.Y20 ) 1.5 × 1012CFU/kg body weight following is safe, thereby indicating that the bacteria to mammals is safe.

  1. "DRUG RESISTANCE PATTERN IN ISOLATED BACTERIA FROM BLOOD CULTURES"

    Directory of Open Access Journals (Sweden)

    A. Sobhani

    2004-05-01

    Full Text Available Bacteremia is an important infectious disease which may lead to death. Common bacteria and pattern of antibiotic resistance in different communities are different and understanding these differences is important. In the present study, relative frequency and pattern of drug resistance have been examined in bacteria isolated from blood cultures in Razi Hospital laboratory. The method of the study was descriptive. Data collection was carried out retrospectively. Total sample consisted of 311 positive blood cultures from 1999 to 2001. Variables under study were bacterial strains, antibiotics examined in antibiogram, microbial resistance, and patients' age and sex. The most common isolated bacteria were Salmonella typhi (22.2% and the least common ones were Citrobacter (1.6%. The highest antibiotic resistance was seen against amoxicillin (88.4%. The proportion of males to females was1: 1/1 and the most common age group was 15-44 (47.3%. Common bacteria and pattern of antibiotic resistance were different in some areas and this subject requires further studies in the future.

  2. Culturing marine bacteria - an essential prerequisite for biodiscovery.

    Science.gov (United States)

    Joint, Ian; Mühling, Martin; Querellou, Joël

    2010-09-01

    The potential for using marine microbes for biodiscovery is severely limited by the lack of laboratory cultures. It is a long-standing observation that standard microbiological techniques only isolate a very small proportion of the wide diversity of microbes that are known in natural environments from DNA sequences. A number of explanations are reviewed. The process of establishing laboratory cultures may destroy any cell-to-cell communication that occurs between organisms in the natural environment and that are vital for growth. Bacteria probably grow as consortia in the sea and reliance on other bacteria for essential nutrients and substrates is not possible with standard microbiological approaches. Such interactions should be considered when designing programmes for the isolation of marine microbes. The benefits of novel technologies for manipulating cells are reviewed, including single cell encapsulation in gel micro-droplets. Although novel technologies offer benefits for bringing previously uncultured microbes into laboratory culture, many useful bacteria can still be isolated using variations of plating techniques. Results are summarized for a study to culture bacteria from a long-term observatory station in the English Channel. Bacterial biodiversity in this assemblage has recently been characterized using high-throughput sequencing techniques. Although Alphaproteobacteria dominated the natural bacterial assemblage throughout the year, Gammaproteobacteria were the most frequent group isolated by plating techniques. The use of different gelling agents and the addition of ammonium to seawater-based agar did lead to the isolation of a higher proportion of Alphaproteobacteria. Variation in medium composition was also able to increase the recovery of other groups of particular interest for biodiscovery, such as Actinobacteria.

  3. Culturing marine bacteria – an essential prerequisite for biodiscovery

    Science.gov (United States)

    Joint, Ian; Mühling, Martin; Querellou, Joël

    2010-01-01

    Summary The potential for using marine microbes for biodiscovery is severely limited by the lack of laboratory cultures. It is a long‐standing observation that standard microbiological techniques only isolate a very small proportion of the wide diversity of microbes that are known in natural environments from DNA sequences. A number of explanations are reviewed. The process of establishing laboratory cultures may destroy any cell‐to‐cell communication that occurs between organisms in the natural environment and that are vital for growth. Bacteria probably grow as consortia in the sea and reliance on other bacteria for essential nutrients and substrates is not possible with standard microbiological approaches. Such interactions should be considered when designing programmes for the isolation of marine microbes. The benefits of novel technologies for manipulating cells are reviewed, including single cell encapsulation in gel micro‐droplets. Although novel technologies offer benefits for bringing previously uncultured microbes into laboratory culture, many useful bacteria can still be isolated using variations of plating techniques. Results are summarized for a study to culture bacteria from a long‐term observatory station in the English Channel. Bacterial biodiversity in this assemblage has recently been characterized using high‐throughput sequencing techniques. Although Alphaproteobacteria dominated the natural bacterial assemblage throughout the year, Gammaproteobacteria were the most frequent group isolated by plating techniques. The use of different gelling agents and the addition of ammonium to seawater‐based agar did lead to the isolation of a higher proportion of Alphaproteobacteria. Variation in medium composition was also able to increase the recovery of other groups of particular interest for biodiscovery, such as Actinobacteria. PMID:21255353

  4. Z-QS01菌株对小球藻的生态学效应及对UV-B辐射的响应%Quorum Sensing of an Associated Heterotrophic Bacteria-Z-QS01 with Chlorella Vulgaris and Response to Enhanced UV-B Radiation

    Institute of Scientific and Technical Information of China (English)

    周文礼; 肖慧; 乔秀亭; 孙敬锋; 邢克智; 唐学玺

    2011-01-01

    利用生态毒理学方法研究了小球藻共栖Z-QS01菌株的生态学效应及对U V-B辐射的响应.结果表明:Z-QS01菌株通过分泌化学物质实现自我行为调节和对小球藻的抑制效应,Z-QS01菌株的密度和分泌到培养液中的化学物质的浓度是启动调节机制的必要条件;UV-B辐射增强显著影响Z-QS01菌株的群感效应,随UV-B辐射剂量的增加,Z-QS01菌株对小球藻的抑制效应降低.实验数据可为水产养殖业生态防病提供参考,并为揭示藻菌间相互作用机制提供有价值的参考资料.%An associated heterotrophic dominant single bacteria-Z-QS01 was selected to study its mechanism of quorum sensing and factors that affected quorum sensing using ecotoxicological technique in co-cultural system with Chlorella vulgaris. The results show that self-regulation and inhibitive effect of bacteria-Z-QS01 to Chlorella vulgaris could implement through excreting chemic substance. Density of bacteria-Z-QS01 and concentration of chemic substance excreted by bacteria-Z-QS01 are the necessary conditions, which decide whether the regulation mechanism could be carried out or not. The enhanced UV-B radiation could affect quorum sensing of bacteria-Z-QS01 significantly, and the inhibitive effect to Chlorella vulgaris is decreased gradually with the dose increase of UV-B radiation.

  5. Effects of biofloc promotion on water quality, growth, biomass yield and heterotrophic community in Litopenaeus vannamei (Boone, 1931 experimental intensive cultures

    Directory of Open Access Journals (Sweden)

    Irasema E. Luis-Villaseñor

    2015-08-01

    Full Text Available Six 1.2-m3 tanks were stocked with an initial biomass of 500 g m-3 of Litopenaeus vannamei juveniles (individual weight: 1.0±0.3 g, to evaluate the effect of biofloc promotion on water quality and on shrimp growth and production, and to identify the dominant taxa in the heterotrophic communities present in experimental closed cultures. Feeding was ad libitum twice daily with 35% protein shrimp feed. Three tanks were managed as biofloc technology (BFT systems, adding daily an amount of cornmeal equivalent to 50% of the shrimp feed supplied. The remaining three received only shrimp feed and served as controls. Experiment lasted 21 days. The mean concentrations of P-PO4 3- and inorganic dissolved N species (TAN, N-NO2 -, N-NO3 - were significantly lower (P<0.5 in BFT than in the control. The individual final weight, increase in biomass, food, and protein conversion rates were significantly better in BFT than in the control (P<0.05. The mean N content of the shrimp biomass gained in the BFT cultures was equivalent to 45.7% of the protein-N added as feed, and was significantly higher than the 34.7% recycled into shrimp biomass in the control cultures. Bacterial concentrations were not significantly different. Vibrionaceae dominated in both systems; in both some isolates were potential pathogens, and diversity was higher in the control than in the BFT treatment. The advantages of BFT technology are confirmed by the significantly lower TAN and N-NO2 - concentrations, as well as by the better shrimp performance in terms of growth, biomass yield, and food and protein conversion efficiency.

  6. 脉冲磁场对电厂循环冷却水中异养菌的灭活%Inactivation of heterotrophic bacteria in circulation cooling water system of power plant by pulsed magnetic field

    Institute of Scientific and Technical Information of China (English)

    武红梅; 刘智安; 薛金英; 刘洋; 周斐博; 王玮

    2012-01-01

    为了控制微生物繁殖对电厂循环冷却水系统造成的危害,研究了脉冲电源发生器与线圈绕组相连产生的脉冲磁场对循环水中异养菌的灭活影响,并对灭活关键因素进行了分析。实验结果表明,脉冲磁场对电厂循环冷却水中的异养菌有灭活作用;灭活率对频率和输出电压有选择性,并且随着作用时间和温度的升高而升高;在扫频范围100~1000 Hz、输出电压3 V、单次作用时间为15 s,温度45℃时,异养菌灭活率达到78.8%。%In order to control the harm caused by microbial growth in circulation cooling water systems,the inactivation of heterotrophic bacteria was investigated with the pulsed magnetic fields generated by DC-pulse generator combining with coil windings.Analyses for key factors of sterilization were carried out.The experimental results revealed that the pulsed magnetic fields have effects on inactivation of heterotrophic bacteria in the circulation cooling water system.The inactivation rates take selectivity for the frequency and output voltage.The inactivation rates increase with the increasing of temperature and time duration for each pulse.When the sweep frequency of pulsed magnetic field ranges from 10 to 1 000 Hz,the output voltage is 3 V,and the time duration for each pulse is 15 s,the inactivation rate is 78.8%.

  7. Heterotrophic activities of bacterioplankton and bacteriobenthos.

    Science.gov (United States)

    Chocair, J A; Albright, L J

    1981-03-01

    Several marine waters and surface sediments of coastal British Columbia were analyzed and compared for bacterial colony forming units (CFU) and numbers of active bacteria (NAB) as indicated by microautoradiography, glucose and alanine heterotrophic activities, and dissolved (DOC) and particulate organic carbon (POC). Bacteria numbers (CFU, NAB) were usually much greater (by several orders of magnitude) in surface sediments than in overlying waters. DOC and POC were also generally greater in surface sediments than in overlying waters, often by as much as one order of magnitude. Both glucose and alanine heterotrophic potentials were greater in surface sediments; however, on a per active cell (NAB) basis, no significant differences were noted between the glucose-specific activities of the bacteria of the surface sediments and overlying waters. The data suggest that these surface sediments carry greater standing crops of bacteria than overlying waters without significant decreases in glucose-specific activities.

  8. Numerical contribution of phytoplanktonic cells, heterotrophic particles and bacteria to size fractionated POC in the Cananéia estuary (25ºS 48ºW, Brazil

    Directory of Open Access Journals (Sweden)

    Hilda de Souza Lima Mesquita

    1985-01-01

    Full Text Available Oxidable POC, at two stations in the Cananéia estuary, was found to be largely dependent upon the smallest size POC. The correlation factors between POC and the numerical abundance of cells, heterotrofic particles and bacteria, in each of the size categories studied, were generally low and non-significant for both stations, with a few exceptions. At St. I the number of heterotrophic particles seems to account for some of the POC variation over the year. At St. II, the only significant correlation found was between the number of the largest and intermediate size classes bacteria and the equivalent size classes POC. At this station the importance of the detritus component is suggested. The differences found between the stations, concerning the numerical contribution of cells, particles and bacteria to total POC, have been attributed to the differential hydrodynamic conditions acting upon material coming from land, due to diverse location of the stations. Sampling date and the collection of different water masses have also been considered as factors that may greatly affect the relationships studied.

  9. Microbial heterotrophic metabolic rates constrain the microbial carbon pump

    Digital Repository Service at National Institute of Oceanography (India)

    Robinson, C.; Ramaiah, N.

    The respiration of dissolved organic matter by heterotrophic bacteria and Archaea represents the largest sink in the global marine biological carbon cycle, an important constraint on organic carbon supply, and the major driver of global elemental...

  10. Biotransformation of pharmaceuticals under nitrification, nitratation and heterotrophic conditions.

    Science.gov (United States)

    Fernandez-Fontaina, E; Gomes, I B; Aga, D S; Omil, F; Lema, J M; Carballa, M

    2016-01-15

    The effect of nitrification, nitratation and heterotrophic conditions on the biotransformation of several pharmaceuticals in a highly enriched nitrifying activated sludge was evaluated in this study by selective activation of ammonia oxidizing bacteria (AOB), nitrite oxidizing bacteria (NOB) and heterotrophic bacteria. Nitrifiers displayed a noticeable capacity to process ibuprofen due to hydroxylation by ammonia monooxygenase (AMO) to produce 2-hydroxy-ibuprofen. Naproxen was also biotransformed under nitrifying conditions. On the other hand, heterotrophic bacteria present in the nitrifying activated sludge (NAS) biotransformed sulfamethoxazole. In contrast, both nitrifying and heterotrophic activities were ineffective against diclofenac, diazepam, carbamazepine and trimethoprim. Similar biotransformation rates of erythromycin, roxithromycin and fluoxetine were observed under all conditions tested. Overall, results from this study give more evidence on the role of the different microbial communities present in activated sludge reactors on the biological removal of pharmaceuticals. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Sensitivity and rapidity of blood culture bottles in the detection of cornea organ culture media contamination by bacteria and fungi

    OpenAIRE

    Thuret, G; Carricajo, A.; Chiquet, C.; Vautrin, A C; Celle, N; Boureille, M; Acquart, S; Aubert, G.; Maugery, J; Gain, P.

    2002-01-01

    Aims: To test the bactericidal activity of standard organ culture medium, and to compare the sensitivity and rapidity of blood culture bottles with conventional microbiological methods for detection of bacteria and fungi inoculated in a standard cornea organ culture medium.

  12. Electromechanical and Elastic Probing of Bacteria in Cell Culture Medium

    Science.gov (United States)

    Thompson, G.L.; Reukov, V.V.; Nikiforov, M.P.; Jesse, S.; Kalinin, S.V.; Vertegel, A.A.

    2012-01-01

    Rapid phenotype characterization and identification of cultured cells, which is needed for progress in tissue engineering and drug testing, requires an experimental technique that measures physical properties of cells with sub-micron resolution. Recently, band excitation piezoresponse force microscopy (BEPFM) has been proven useful for recognition and imaging of different types of bacteria in pure water. Here, the BEPFM method is performed for the first time in physiologically-relevant electrolyte media, such as Dulbecco’s phosphate-buffered saline (DPBS) and Dulbecco’s modified Eagle’s medium (DMEM). Distinct electromechanical responses for Micrococcus lysodeikticus (Gram-positive) and Pseudomonas fluorescens (Gram-negative) bacteria are demonstrated in DPBS. The results suggest that mechanical properties of the outer surface coating each bacterium, as well as the electrical double layer around them, are responsible for the BEPFM image formation mechanism in electrolyte media. PMID:22641388

  13. Heavy metal pollution exerts reduction/adaptation in the diversity and enzyme expression profile of heterotrophic bacteria in Cochin estuary, India

    Digital Repository Service at National Institute of Oceanography (India)

    Jose, J.; Giridhar, R.; Anas, A.; LokaBharathi, P.A.; Nair, S.

    enzyme. In conclusion, the heavy metal pollution in Cochin estuary brought in reduction/adaptation in the distribution, diversity and enzyme expression profile of bacteria, which may impart adverse impacts on ecosystem functioning....

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

    Science.gov (United States)

    Çiftçi Türetken, Pelin S; Altuğ, Gülşen

    2016-02-01

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

  15. Novel approach for the ammonium removal by simultaneous heterotrophic nitrification and denitrification using a novel bacterial species co-culture.

    Science.gov (United States)

    Angar, Yassmina; Kebbouche-Gana, Salima; Djelali, Nacer-Eddine; Khemili-Talbi, Souad

    2016-03-01

    Agricultural activities lead excessive emission of ammonia nitrogen in the environment and can profoundly interfere the equilibrium of the natural ecosystems leading to their contamination. Actually, the biological purification of wastewaters is the most adopted technique thanks to its several advantages such as high performance and low energy consumption. For this reason, two novel strains of Alcaligenes sp. S84S3 and Proteus sp. S19 genus were isolated from an activated sludge and applied in the treatment of ammonium and nitrite in aqueous solution. Under the optimum operating conditions of temperature (30 °C), pH (7), carbon substrate (2 g/L of glucose) and duration of incubation time (69 h), the strain Alcaligenes sp. S84S3 could oxidize 65% of the ammonium as high as 272.72 mg-NH4(+)/L. Moreover, during 48 h, the nitrate reduction rate performed by the strain Proteus S19 was about 99 % without production of nitrite intermediate (negligible concentration). Moreover, the coculture of the strains Alcaligenes sp. S84S3 and Proteus sp. S19 could eliminate 65.83% of the ammonium ions without production of toxic forms of nitrogen oxides during a short time of incubation (118 h) at the same operational conditions with providing the aeration in the first treatment phase. The coculture of our isolated strains is assumed to have a good potential for nitrification and denitrification reactions applied in the treatment of wastewater containing ammonium, nitrite and nitrate. As a result, we can consider that the mixed culture is a practical method in the treatment of high-strength ammonium wastewater with reducing of sludge production.

  16. The presence of embedded bacterial pure cultures in agar plates stimulate the culturability of soil bacteria

    DEFF Research Database (Denmark)

    Burmølle, Mette; Johnsen, Kaare; Abu Al-Soud, Waleed Mohamad Abdel F

    2009-01-01

    Traditional methods for bacterial cultivation recover only a small fraction of bacteria from all sorts of natural environments, and attempts have been made to improve the bacterial culturability. Here we describe the development of a cultivation method, based on the embedment of pure bacterial cu...

  17. Surface modification of substrates for bacteria and cell culture.

    Science.gov (United States)

    Baede, Tom; Sladek, Raymond; Stoffels, Eva

    2006-10-01

    The plasma needle is a medical device that consists of a tungsten wire placed in a tube through which helium flows. A RF voltage frequency of 13.05 MHz is applied to the wire to produce the plasma. The device has a non-thermal effect and is therefore suited for both organic and inorganic surfaces. It was designed to manipulate tissues, but can also be used to modify the bacterial adhesion properties of material surfaces. The surface modification has a number of applications, most notably cell culture and the preventive treatment of caries. The research consists of two sets of experiments. In the first experiments the effect of the plasma treatment on the wettability was studied by means of contact angle measurements. The wettability quantifies the hydrophilic behavior of a surface. Plasma treatment with the plasma needle significantly increased the wettability of the studied materials. The persistence of the wettability change was also examined. For some materials the effect was only temporary. Bacteria are very particular about the surfaces they adhere to and the wettability of the surface plays an important role in their preference. The next set of experiments dealt with the effect of plasma treatment on bacterial adhesion. This effect was measured by comparing the growth rates of E. coli and S. mutans bacteria that were cultured on both plasma and non-treated surfaces. The effect appears to be species specific.

  18. An approach to measure ciliate grazing on living heterotrophic nanoflagellates

    DEFF Research Database (Denmark)

    Christoffersen, K.; González, J. M.

    2003-01-01

    . Here we present an approach for the assessment of ciliate grazing on living heterotrophic nanoflagellates. Stationary phase cultures of a heterotrophic nanoflagellate (Cafeteria sp.) were live-stained by allowing them to take up fluorescently labelled macromolecules. Controls revealed that this label...

  19. Bioprecipitation of Calcium Carbonate Crystals by Bacteria Isolated from Saline Environments Grown in Culture Media Amended with Seawater and Real Brine

    Directory of Open Access Journals (Sweden)

    G. A. Silva-Castro

    2015-01-01

    Full Text Available The precipitation of calcium carbonate and calcium sulphate by isolated bacteria from seawater and real brine obtained in a desalination plant growth in culture media containing seawater and brine as mineral sources has been studied. However, only bioprecipitation was detected when the bacteria were grown in media with added organic matter. Biomineralization process started rapidly, crystal formation taking place in the beginning a few days after inoculation of media; roughly 90% of total cultivated bacteria showed. Six major colonies with carbonate precipitation capacity dominated bacterial community structure cultivated in heterotrophic platable bacteria medium. Taxonomic identification of these six strains through partial 16S rRNA gene sequences showed their affiliation with Gram-positive Bacillus and Virgibacillus genera. These strains were able to form calcium carbonate minerals, which precipitated as calcite and aragonite crystals and showed bacterial fingerprints or bacteria calcification. Also, carbonic anhydrase activity was observed in three of these isolated bacteria. The results of this research suggest that microbiota isolated from sea water and brine is capable of precipitation of carbonate biominerals, which can occur in situ with mediation of organic matter concentrations. Moreover, calcium carbonate precipitation ability of this microbiota could be of importance in bioremediation of CO2 and calcium in certain environments.

  20. Effect of low-frequency pulsed magnetic field on heterotrophic bacteria in circulation cooling water at power plants%低频脉冲磁场对电厂循环冷却水异养菌的影响

    Institute of Scientific and Technical Information of China (English)

    薛金英; 刘智安; 武红梅; 乔波波; 周斐博

    2012-01-01

    The bactericidal experiments of low-frequency pulsed magnetic field have been carried out, aiming at two aspects: the change of variable frequency pulse magnetic field direction, and the two directions of fixed frequency and sweep frequency range. The experimental results show that the change of microbiological physiological function took place under the magnetic field effect. The variable-frequency pulsed magnetic field not only can inhibit the growth of heterotrophic bacteria in circulating cooling water, but also can stimulate the reproduction of heterotrophic bacteria. When the direction of magnetic field is parallel and perpendicular with the water flow direction, the bactericidal rate reaches more than 70%. When the direction of magnetic field is parallel with the water flow direction in the range of 11-17 kHz sweep frequency, the bactericidal rate can reach 82.64%. Therefore, the effective sweep frequency range should be determined,when low frequency pulsed magnetic field is made use of. Thus,better bactericidal effect can be obtained.%从变频脉冲磁场方向的变化以及固定频率与扫频范围两个方向进行了低频脉冲磁场的杀菌实验.实验表明微生物生理功能在磁场作用下发生改变,变频脉冲电磁场既能抑制循环水中异养菌的生长,也能刺激异养菌的繁衍;当磁场方向与水流方向平行和垂直时能达到70%以上的杀菌率,其中磁场方向与水流方向平行时在11~17 kHz频率范围内的杀菌率达到82.64%.因此利用低频脉冲磁场进行杀菌时应确定有效的扫频范围,才能达到较好的杀菌效果.

  1. Improving diversity in cultures of bacteria from an extreme environment.

    Science.gov (United States)

    Vester, Jan Kjølhede; Glaring, Mikkel Andreas; Stougaard, Peter

    2013-08-01

    The ikaite columns in the Ikka Fjord in Greenland represent one of the few permanently cold and alkaline environments on Earth, and the interior of the columns is home to a bacterial community adapted to these extreme conditions. The community is characterized by low cell numbers imbedded in a calcium carbonate matrix, making extraction of bacterial cells and DNA a challenge and limiting molecular and genomic studies of this environment. To utilize this genetic resource, cultivation at high pH and low temperature was studied as a method for obtaining biomass and DNA from the fraction of this community that would not otherwise be amenable to genetic analyses. The diversity and community dynamics in mixed cultures of bacteria from ikaite columns was investigated using denaturing gradient gel electrophoresis and pyrosequencing of 16S rDNA. Both medium composition and incubation time influenced the diversity of the culture and many hitherto uncharacterized genera could be brought into culture by extended incubation time. Extended incubation time also gave rise to a more diverse community with a significant number of rare species not detected in the initial community.

  2. 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...

  3. Sponge-associated bacteria of Lakshadweep coral reefs, India: resource for extracellular hydrolytic enzymes

    Digital Repository Service at National Institute of Oceanography (India)

    Feby, A.; Nair, S.

    % of the sponge-associated bacteria expressed multiple enzymatic activities (greater than equal to 4) with variation in the percentage of expression of individ-ual enzymes. More than 65% of the culturable het-erotrophic bacteria associated with sponges were...

  4. Acidophilic algae isolated from mine-impacted environments and their roles in sustaining heterotrophic acidophiles

    Directory of Open Access Journals (Sweden)

    David Barrie Johnson

    2012-09-01

    Full Text Available Two acidophilic algae, identified as strains of Chlorella protothecoides var. acidicola and Euglena mutabilis, were isolated in pure culture from abandoned copper mines in Spain and Wales and grown in pH- and temperature-controlled bioreactors. The Chlorella isolate grew optimally at pH 2.5 and 30 ˚C, with a corresponding culture doubling time of 9 hours. The isolates displayed similar tolerance (10-50 mM to four transition metals tested. Growth of the algae in liquid media was paralleled with increasing concentrations of dissolved organic carbon (DOC. Glycolic acid was identified as a significant component (12- 14% of total DOC. Protracted incubation resulted in concentrations of glycolic acid declining in both cases, and glycolic acid added to a culture of Chlorella incubated in the dark was taken up by the alga (~100% within three days. Two monosaccharides were identified in cell-free liquors of each algal isolate: fructose and glucose (Chlorella, and mannitol and glucose (Euglena. These were rapidly metabolised by acidophilic heterotrophic bacteria (Acidiphilium and Acidobacterium spp. though only fructose was utilised by the more fastidious heterotroph Acidocella aromatica. The significance of algae in promoting the growth of iron- (and sulfate- reducing heterotrophic acidophiles that are important in remediating mine-impacted waters is discussed.

  5. Biotransformation of pharmaceuticals under nitrification, nitratation and heterotrophic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Fontaina, E., E-mail: eduardo.fernandez.fontaina@usc.es [Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, 15782 Santiago de Compostela (Spain); Gomes, I.B. [Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, 15782 Santiago de Compostela (Spain); Aga, D.S. [Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, NY 14260 (United States); Omil, F.; Lema, J.M.; Carballa, M. [Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, 15782 Santiago de Compostela (Spain)

    2016-01-15

    The effect of nitrification, nitratation and heterotrophic conditions on the biotransformation of several pharmaceuticals in a highly enriched nitrifying activated sludge was evaluated in this study by selective activation of ammonia oxidizing bacteria (AOB), nitrite oxidizing bacteria (NOB) and heterotrophic bacteria. Nitrifiers displayed a noticeable capacity to process ibuprofen due to hydroxylation by ammonia monooxygenase (AMO) to produce 2-hydroxy-ibuprofen. Naproxen was also biotransformed under nitrifying conditions. On the other hand, heterotrophic bacteria present in the nitrifying activated sludge (NAS) biotransformed sulfamethoxazole. In contrast, both nitrifying and heterotrophic activities were ineffective against diclofenac, diazepam, carbamazepine and trimethoprim. Similar biotransformation rates of erythromycin, roxithromycin and fluoxetine were observed under all conditions tested. Overall, results from this study give more evidence on the role of the different microbial communities present in activated sludge reactors on the biological removal of pharmaceuticals. - Highlights: • The removal of pharmaceuticals in nitrifying activated sludge (NAS) was studied. • Nitrifying activity increases biotransformation rate of ibuprofen and naproxen. • Hydroxylation of ibuprofen by ammonia monooxygenase of ammonia oxidizing bacteriaHeterotrophic activity enhances biotransformation of sulfamethoxazole in NAS. • Recalcitrance of trimethoprim, diclofenac, carbamazepine and diazepam in NAS.

  6. Natural hot spots for gain of multiple resistances: arsenic and antibiotic resistances in heterotrophic, aerobic bacteria from marine hydrothermal vent fields.

    Science.gov (United States)

    Farias, Pedro; Espírito Santo, Christophe; Branco, Rita; Francisco, Romeu; Santos, Susana; Hansen, Lars; Sorensen, Soren; Morais, Paula V

    2015-04-01

    Microorganisms are responsible for multiple antibiotic resistances that have been associated with resistance/tolerance to heavy metals, with consequences to public health. Many genes conferring these resistances are located on mobile genetic elements, easily exchanged among phylogenetically distant bacteria. The objective of the present work was to isolate arsenic-, antimonite-, and antibiotic-resistant strains and to determine the existence of plasmids harboring antibiotic/arsenic/antimonite resistance traits in phenotypically resistant strains, in a nonanthropogenically impacted environment. The hydrothermal Lucky Strike field in the Azores archipelago (North Atlantic, between 11°N and 38°N), at the Mid-Atlantic Ridge, protected under the OSPAR Convention, was sampled as a metal-rich pristine environment. A total of 35 strains from 8 different species were isolated in the presence of arsenate, arsenite, and antimonite. ACR3 and arsB genes were amplified from the sediment's total DNA, and 4 isolates also carried ACR3 genes. Phenotypic multiple resistances were found in all strains, and 7 strains had recoverable plasmids. Purified plasmids were sequenced by Illumina and assembled by EDENA V3, and contig annotation was performed using the "Rapid Annotation using the Subsystems Technology" server. Determinants of resistance to copper, zinc, cadmium, cobalt, and chromium as well as to the antibiotics β-lactams and fluoroquinolones were found in the 3 sequenced plasmids. Genes coding for heavy metal resistance and antibiotic resistance in the same mobile element were found, suggesting the possibility of horizontal gene transfer and distribution of theses resistances in the bacterial population.

  7. 9 CFR 113.25 - Culture media for detection of bacteria and fungi.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Culture media for detection of bacteria and fungi. 113.25 Section 113.25 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION... STANDARD REQUIREMENTS Standard Procedures § 113.25 Culture media for detection of bacteria and fungi. (a...

  8. Different Abilities of Eight Mixed Cultures of Methane-oxidizing Bacteria to Degrade TCE

    DEFF Research Database (Denmark)

    Broholm, Kim; Christensen, Thomas Højlund; Jensen, Bjørn K.

    1993-01-01

    The ability of eight mixed cultures of methane-oxidizing bacteria to degrade trichloroethylene (TCE) was examined in laboratory batch experiments. This is one of the first reported works studying TCE degradation by mixed cultures of methane-oxidizing bacteria at 10°C, a common temperature for soils...

  9. Impact of lactate on growth of cultures of cecal bacteria from commercial broilers

    Science.gov (United States)

    Cultures of beneficial bacteria used in probiotics produce and utilize organic acids that may play a role in the ability of the cultures to inhibit colonization of poultry by enteropathogens. Cecal contents of adult poultry contain many of these beneficial bacteria, and earlier experiments showed th...

  10. Efficacy of Antimicrobials on Bacteria Cultured in a Spaceflight Analogue

    Science.gov (United States)

    Nickerson, CA; Wotring, Virginia; Barrila, Jennifer; Crabbe, Aurelie; Castro, Sarah; Davis, Richard; Rideout, April; McCarthy, Breanne; Ott, C. Mark

    2014-01-01

    As humans travel in space, they will interact with microbial flora from themselves, other crewmembers, their food, and the environment. While evaluations of microbial ecology aboard the Mir and ISS suggest a predominance of common environmental flora, the presence of (and potential for) infectious agents has been well documented. Likewise, pathogens have been detected during preflight monitoring of spaceflight food, resulting in the disqualification of that production lot from flight. These environmental and food organisms range from the obligate pathogen, Salmonella enterica serovar Typhimurium (S. Typhimurium), which has been responsible for disqualification and removal of food destined for ISS and has previously been reported from Shuttle crew refuse, to the opportunistic pathogen Staphylococcus aureus, isolated numerous times from ISS habitable compartments and the crew. Infectious disease events have affected spaceflight missions, including an upper respiratory infection that delayed the launch of STS-36 and an incapacitating Pseudomonas aeruginosa urinary tract infection of a crewmember during Apollo 13. These observations indicate that the crew has the potential to be exposed to obligate and opportunistic pathogens. This risk of exposure is expected to increase with longer mission durations and increased use of regenerative life support systems. As antibiotics are the primary countermeasure after infection, determining if their efficacy during spaceflight missions is comparable to terrestrial application is of critical importance. The NASA Rotating Wall Vessel (RWV) culture system has been successfully used as a spaceflight culture analogue to identify potential alterations in several key microbial characteristics, such as virulence and gene regulation, in response to spaceflight culture. We hypothesized that bacteria cultured in the low fluid shear RWV environment would demonstrate changes in efficacy of antibiotics compared to higher fluid shear controls

  11. Heterotrophic Mass Cultures of Chlorella Vulgaris with Glucose Feeding in Fermenters%发酵罐葡萄糖流加大规模异养培养小球藻

    Institute of Scientific and Technical Information of China (English)

    梁世中; 朱明军; 孟海华; 尹建云; 陈峰

    2000-01-01

    应用流加工艺在5,50,200,800,4 000 L机械搅拌发酵罐中大规模异养培养小球藻.与间歇异养或光照自养相比,流加培养大大地提高了细胞密度和生产率.最高细胞质量浓度达到43.31 g/L,比生长速率达到0.069 h-1,细胞生产率达到0.62 g/(L·h).结果表明,利用传统的机械搅拌发酵罐大规模生产小球藻有良好的商业化前景.%Chlorella vulgaris was heterotrophically cultured in 5, 50, 200, 800, and 4 000 L stirred tank fermenters with glucose feeding,which gave significant improvement in cell density and productivity compared to batch culture. The highest cell dry weight mass concentration reached 43.31 g/L.The specific growth rate was 0.069 h-1. The cell productivity was 0.62 g/(L·h). The results suggest Chlorella vulgaris can be heterotrophically produced in stirred tank fermenters for commercial use.

  12. [Influence of predominant aerobic bacteria isolated from different healthy animals on daidzein biotransforming capacity by co-culture with different daidzein biotransforming bacteria].

    Science.gov (United States)

    Luo, Jinglong; Wang, Xiuling; Fan, Jinru; Wang, Shiying; Li, Jia

    2011-08-01

    To investigate the influence of isolated predominant aerobic bacteria on daidzein biotransformation capacity by co-culture with daidzein biotransforming bacteria. Predominant aerobic bacteria were isolated from diluted feces solutions of different healthy animals, including ICR mice, Luhua chicken, Landrace pigs and Rex rabbits. Daidzein biotransforming bacteria were anaerobically co-cultured with the isolated predominant aerobic bacteria and the cultural broth was extracted and detected by high performance liquid chromatography (HPLC). Twenty two predominant aerobic bacteria were isolated from the four different healthy animals mentioned above. Based on the analyses of 16S rRNA gene sequences, morphology study and relative biophysico-biochemical characteristics, all 22 isolates belong to the 5 genera, i. e. Escherichia (10) , Proteus (5) , Enterococcus (4), Bacillus (2) and Pseudomonas (1). Co-culture between predominant aerobic bacteria and daidzein biotransforming bacteria was carried out under anaerobic conditions. The results showed that the biotransformation capacity was totally lost when different daidzein biotransforming bacterium was co-cultured with either Bacillus cereus ( R1 ) or Pseudomonas aerginosa (R5) and continuously inoculated for 2 or 3 passages. However, no obvious influence was observed when daidzein biotransforming bacteria were co-cultured with all the other isolated predominant aerobic bacteria except R1 and R5. In addition, when strain R1 and R5 was co-cultured with the intestinal microflora of the ICR mice anaerobically and continuously inoculated for 5 passages, about 90% of the co-cultures totally lost the activity to convert daidzein to equol effectively. Different predominant aerobic bacteria showed different influence on daidzein biotransformation capacity after being co-cultured with different daidzein biotransforming bacteria. Among all the isolated predominant aerobic bacteria used for co-culture, both Bacillus cereus ( R1) and

  13. Exploration and prediction of interactions between methanotrophs and heterotrophs.

    Science.gov (United States)

    Stock, Michiel; Hoefman, Sven; Kerckhof, Frederiek-Maarten; Boon, Nico; De Vos, Paul; De Baets, Bernard; Heylen, Kim; Waegeman, Willem

    2013-12-01

    Methanotrophs can form the basis of a methane-driven food web on which heterotrophic microorganisms can feed. In return, these heterotrophs can stimulate growth of methanotrophs in co-culture by providing growth additives. However, only a few specific interactions are currently known. We incubated nine methanotrophs with 25 heterotrophic strains in a pairwise miniaturized co-cultivation setup. Through principal component analysis and k-means clustering, methanotrophs and heterotrophs could be grouped according to their interaction behaviour, suggesting strain-dependent methanotroph-heterotroph complementarity. Co-cultivation significantly enhanced the growth parameters of three methanotrophs. This was most pronounced for Methylomonas sp. M5, with a threefold increase in maximum density and a fourfold increase in maximum increase in density in co-culture with Cupriavidus taiwanensis LMG 19424. In contrast, co-cultivation with Methylobacterium radiotolerans LMG 2269 and Pseudomonas aeruginosa LMG 12228 inhibited growth of most methanotrophs. Functional genomic analysis suggested the importance of vitamin metabolism for co-cultivation success. The generated data set was then successfully exploited as a proof-of-principle for predictive modelling of co-culture responses based on other interactions of the same heterotrophs and methanotrophs, yielding values of the area under the receiver operating characteristic curve of 0.73 upon 50% missing values for the maximum increase in density parameter. As such, these modelling-based tools were shown to hold great promise in reducing the amount of data that needs to be generated when conducting large co-cultivation studies.

  14. Antibiotic Resistance of Gram Negative Bacteria Isolated From Urine Cultures in Our Laboratory

    Directory of Open Access Journals (Sweden)

    Hakan Temiz

    2008-12-01

    Full Text Available In this study; we analyzed the antimicrobial susceptibility of Gram negative bacteria isolated from urine cultures in the Microbiology Laboratory of Dicle University Medical Faculty Hospital from January 2006 to December 2006; retrospectively. Escherichia coli and Klebsiella species were the most frequently isolated bacteria from both outpatients and hospitalized patients. The most effective antibiotics to these bacteria were carbapenems. These results were suggested to be useful for empirical treatment of urinary system infections in our hospital.

  15. [Improved culturability of soil bacteria using proper combination with various culturing medium].

    Science.gov (United States)

    Hu, Yuan-Sen; Li, Cui-Xiang; Sun, Fu-Lin; Wu, Kun; Jia, Xin-Cheng

    2007-10-01

    To isolate more unique and previously unrecognized bacteria in soil samples, the culture difference under three incubation modes was investigated by using trophic, low-nutrient broth and soil extract as growth medium. Plate count proved that the oligotrophic medium resulted in a slow growth and consecutive colony formation over the course of incubation. On the 5th day, the most number of colony-forming unit was found on trophic LB and low-nutrient R2A, which was approximate 5 times as many as that isolated on 0.1 x LB. Of the 7 media, LB broth harvested the maximum bacterial communities, and novel species could be isolated as the nutrient was diluted to appropriate extent. The DGGE patterns of oligotrophic and rich nutrient culture collection displayed low similarity, however, the bands at various lanes exhibited complementary effect. When cultivated with static flask, LB and R2A media obtained more bacterial species, which concluded most species isolated by the other five media. Under the test tube incubation mode, the most species was also found in LB medium except some appeared only on R2A and TSB. Apparent bacterial communities difference could be detected between R2A, LB and TSB media. The experiment data may contribute much to the special medium design as well as improvement of bacterial culturability by using proper medium.

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

    National Research Council Canada - National Science Library

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

    2016-01-01

    ... 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...

  17. Improved apparatus for continuous culture of hydrogen-fixing bacteria

    Science.gov (United States)

    Foster, J. F.; Litchfield, J. H.

    1970-01-01

    Improved apparatus permits the continuous culture of Hydrogenomonas eutropha. System incorporates three essential subsystems - /1/ environmentally isolated culture vessel, /2/ analytical system with appropriate sensors and readout devices, /3/ control system with feedback responses to each analytical measurement.

  18. Implementing sponge physiological and genomic information to enhance the diversity of its culturable associated bacteria.

    Science.gov (United States)

    Lavy, Adi; Keren, Ray; Haber, Markus; Schwartz, Inbar; Ilan, Micha

    2014-02-01

    In recent years new approaches have emerged for culturing marine environmental bacteria. They include the use of novel culture media, sometimes with very low-nutrient content, and a variety of growth conditions such as temperature, oxygen levels, and different atmospheric pressures. These approaches have largely been neglected when it came to the cultivation of sponge-associated bacteria. Here, we used physiological and environmental conditions to reflect the environment of sponge-associated bacteria along with genomic data of the prominent sponge symbiont Candidatus Poribacteria sp. WGA-4E, to cultivate bacteria from the Red Sea sponge Theonella swinhoei. Designing culturing conditions to fit the metabolic needs of major bacterial taxa present in the sponge, through a combined use of diverse culture media compositions with aerobic and microaerophilic states, and addition of antibiotics, yielded higher diversity of the cultured bacteria and led to the isolation of novel sponge-associated and sponge-specific bacteria. In this work, 59 OTUs of six phyla were isolated. Of these, 22 have no close type strains at the species level (bacteria species, and some are probably new genera and even families.

  19. [Cooperation of mixed culturing bacteria in the hydrogen production by fermentation].

    Science.gov (United States)

    Lin, Ming; Ren, Nanqi; Wang, Aijie; Wang, Xiangjing

    2003-03-01

    In order to discuss the cooperation of H2-producing fermentation bacteria (HPFB) in mixed culture, a batch test fed with glucose and complex organic substance (starch, beef, PEP and peptone) respectively, was conducted to investigate the effects of mixed culture on H2-producing ability. For the systemic and accurate analysis, three kinds of the mixed culture were use to this batch test. It included that the mixed culture with five strains of HPFB (B49, H1, LM12, LM11 and B51), B49 and three stains of non-HPFB (L10, Bacteroide 3-2, Sporobacterl), and B49 and hydrogen producing sludge. The results showed that the cooperation of mixed culturing bacteria was conditional on the substrates. When fed with glucose, which were easily utilized by HPB, the H2-producing ability of HPB was restrained because of the competition on the co-substrate between HPB and other fermentation bacteria, and it was quite difficult for the cooperation of mixed culturing bacteria to be performed. When fed with complex organic substance, the H2-producing ability of HPB was enhanced via the cooperation of mixed culturing bacteria. Furthermore, a strategy was put forward, that is, different kind of HPB cultures could be adopted according to the difference of substrates.

  20. Production of halomethanes and isoprene in the culture of bacteria isolated from brackish water

    Science.gov (United States)

    Fujimori, T.; Taniai, G.; Kurihara, M.; Tamegai, H.; Hashimoto, S.

    2010-12-01

    Halomethanes produced naturally are important source of halogen in troposphere and stratosphere. In the ocean, macroalgae and phytoplankton have been considered to be the main producers of halomethanes. Recent investigations have shown that marine bacteria also produces halomethane such as iodomethane. However, knowledge of aquatic halomethane production, especially by bacteria, is insufficient. Here we survey bacteria, which produce volatile organic compounds (VOCs) including halomethanes, from brackish area (salinity: about 5‰) where high halomethane productions were observed. Bacteria was isolated and incubated in marine broth 2216, which is the media for marine bacteria. The VOCs such as halomethanes in the gas phase above cultured samples was determined using dynamic headspace (GESTEL DHS) - gas chromatograph (Agilent 6890N)- mass spectrometer (Agilent 5975C). The optical density at 600 nm (OD600) was also measured during the cultured period. From the result of the isolation and measurement of VOCs, some of the isolated bacteria produced halomethanes. For example, monohalomethanes (from 1 to about 600 nM) and isoprene (up to about 400 nM) were increased for several days in the culture (dibromomethane, chloroiodomethane, bromoiodomethane, and tribromomethane were not detected). Since halomethanes are abundant at the sampling point (under 1% of light intensity of the surface), bacteria is one of the possible candidates for halomethane producer there. Now, we are studying on the identification by 16S rRNA sequence analysis of bacteria collected from brackish water.

  1. High-Level Culturability of Epiphytic Bacteria and Frequency of Biosurfactant Producers on Leaves

    Science.gov (United States)

    Burch, Adrien Y.; Do, Paulina T.; Sbodio, Adrian; Suslow, Trevor V.

    2016-01-01

    ABSTRACT To better characterize the bacterial community members capable of biosurfactant production on leaves, we distinguished culturable biosurfactant-producing bacteria from nonproducers and used community sequencing to compare the composition of these distinct cultured populations with that from DNA directly recovered from leaves. Communities on spinach, romaine, and head lettuce leaves were compared with communities from adjacent samples of soil and irrigation source water. Soil communities were poorly described by culturing, with recovery of cultured representatives from only 21% of the prevalent operational taxonomic units (OTUs) (>0.2% reads) identified. The dominant biosurfactant producers cultured from soil included bacilli and pseudomonads. In contrast, the cultured communities from leaves are highly representative of the culture-independent communities, with over 85% of the prevalent OTUs recovered. The dominant taxa of surfactant producers from leaves were pseudomonads as well as members of the infrequently studied genus Chryseobacterium. The proportions of bacteria cultured from head lettuce and romaine leaves that produce biosurfactants were directly correlated with the culture-independent proportion of pseudomonads in a given sample, whereas spinach harbored a wider diversity of biosurfactant producers. A subset of the culturable bacteria in irrigation water also became enriched on romaine leaves that were irrigated overhead. Although our study was designed to identify surfactant producers on plants, we also provide evidence that most bacteria in some habitats, such as agronomic plant surfaces, are culturable, and these communities can be readily investigated and described by more classical culturing methods. IMPORTANCE The importance of biosurfactant production to the bacteria that live on waxy leaf surfaces as well as their ability to be accurately assessed using culture-based methodologies was determined by interrogating epiphytic populations by

  2. Isolation and characterization of culturable bacteria from bulk soil ...

    African Journals Online (AJOL)

    Olaf _SK

    2015-03-18

    Mar 18, 2015 ... Plant growth promoting bacteria affect both growth and development of .... grown for 24 h using the Zymo Research ZR Soil Microbe DNA. MiniPrep™ Catalog ... stained with 5 μl of 10 mg/ml ethidium bromide and visualised.

  3. biodegradation of endosulfan by mixed bacteria culture strains of ...

    African Journals Online (AJOL)

    Nwokem et al.

    this study, endosulfan was degraded by indigenous bacteria strains of ... acute threats to human health, and long-term low-dose exposure to pesticides causes ... Biostimulation involves modification within the environment to ... subsurface through injection wells, although injection well technology .... aluminum foil. The flasks ...

  4. Culturable diversity of halophilic bacteria in foreshore soils

    Directory of Open Access Journals (Sweden)

    Aarzoo Irshad

    2014-06-01

    Full Text Available Halophilic bacteria are commonly found in natural environments containing significant concentration of NaCl such as inland salt lakes and evaporated sea-shore pools, as well as environments such as curing brines, salted food products and saline soils. Dependence on salt is an important phenotypic characteristic of halophilic bacteria, which can be used in the polyphasic characterization of newly discovered microorganisms. In this study the diversity of halophilic bacteria in foreshore soils of Daecheon, Chungnam, and Saemangeum, Jeonbuk, was investigated. Two types of media, namely NA and R2A supplemented with 3%, 5%, 9%, 15%, 20% and 30% NaCl were used. More than 200 halophilic bacteria were isolated and BOX-PCR fingerprinting analysis was done for the typing of the isolates. The BLAST identification results showed that isolated strains were composed of 4 phyla, Firmicutes (60%, Proteobacteria (31%, Bacteriodetes (5% and Actinobacteria (4%. Isolates were affiliated with 16 genera and 36 species. Bacillus was the dominant genus in the phylum Firmicutes, comprising 24% of the total isolates. Halomonas (12% and Shewanella (12% were also found as the main genera. These findings show that the foreshore soil of Daecheon Beach and Saemangeum Sea of Korea represents an untapped source of bacterial biodiversity.

  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. 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

  7. Process for inhibiting the growth of a culture of lactic acid bacteria, and optionally lysing the bacterial cells, and uses of the resulting lysed culture

    NARCIS (Netherlands)

    Nauta, Arjen; Venema, Gerard; Kok, Jan; Ledeboer, Aat M.

    1995-01-01

    The invention provides a process for inhibiting the growth of a culture of lactic acid bacteria, or a product containing such culture e.g. a cheese product, in which in the cells of the lactic acid bacteria a holin obtainable from bacteriophages of Gram-positive bacteria, esp. from bacteriophages of

  8. Enrichment culture of marine anaerobic ammonium oxidation (anammox) bacteria

    Institute of Scientific and Technical Information of China (English)

    GUAN Yong-jie

    2016-01-01

    The present study investigates the enrichment of anaerobic ammonium oxidation (anammox) bacteria in the marine environment using sediment samples obtained from the East China Sea and discusses the nitrogen removal efficiency of marine anammox bioreactor. Enrichment of anammox bacteria with simultaneous removal of nitrite and ammonium ions was observed in the Anaerobic Sequencing Batch Reactor under a total nitrogen loading rate of 0.37kg-N m-3day-1. In this study, The nitrogen removal efficiency was up to 80% and the molar-reaction ratio of ammonium, nitrite and nitrate was 1.0:1.22:0.22 which was a little different from a previously reported ratio of 1.0:1.32:0.26 in a freshwater system.

  9. Mixed cultures of Kimchi lactic acid bacteria show increased cell ...

    African Journals Online (AJOL)

    ufuoma

    kimchi lactobacilli on batch fermentation increased the cell density and lactic acid production with low nutrients .... first series of fermentations were carried out using pure cultures of each ... Each number represents the mean. ± SD of three ...

  10. [Culturable psychrotolerant methanotrophic bacteria in landfill cover soil].

    Science.gov (United States)

    Kallistova, A Iu; Montonen, L; Jurgens, G; Munster, U; Kevbrina, M V; Nozhevnikova, A N

    2014-01-01

    Methanotrophs closely related to psychrotolerant members of the genera Methylobacter and Methylocella were identified in cultures enriched at 10@C from landfill cover soil samples collected in the period from April to November. Mesophilic methanotrophs of the genera Methylobacter and Methylosinus were found in cultures enriched at 20 degrees C from the same cover soil samples. A thermotolerant methanotroph related to Methylocaldum gracile was identified in the culture enriched at 40 degrees C from a sample collected in May (the temperature of the cover soil was 11.5-12.5 degrees C). In addition to methanotrophs, methylobacteria of the genera Methylotenera and Methylovorus and members of the genera Verrucomicrobium, Pseudomonas, Pseudoxanthomonas, Dokdonella, Candidatus Protochlamydia, and Thiorhodospira were also identified in the enrichment cultures. A methanotroph closely related to the psychrotolerant species Methylobacter tundripaludum (98% sequence identity of 16S r-RNA genes with the type strain SV96(T)) was isolated in pure culture. The introduction of a mixture of the methanotrophic enrichments, grown at 15 degrees C, into the landfill cover soil resulted in a decrease in methane emission from the landfill surface in autumn (October, November). The inoculum used was demonstrated to contain methanotrophs closely related to Methylobacter tundripaludum SV96.

  11. Bacteria abundance and diversity of different life stages of Plutella xylostella (Lepidoptera: Plutellidae), revealed by bacteria culture-dependent and PCR-DGGE methods.

    Science.gov (United States)

    Lin, Xiao-Li; Pan, Qin-Jian; Tian, Hong-Gang; Douglas, Angela E; Liu, Tong-Xian

    2015-03-01

    Microbial abundance and diversity of different life stages (fourth instar larvae, pupae and adults) of the diamondback moth, Plutella xylostella L., collected from field and reared in laboratory, were investigated using bacteria culture-dependent method and PCR-DGGE analysis based on the sequence of bacteria 16S rRNA V3 region gene. A large quantity of bacteria was found in all life stages of P. xylostella. Field population had higher quantity of bacteria than laboratory population, and larval gut had higher quantity than pupae and adults. Culturable bacteria differed in different life stages of P. xylostella. Twenty-five different bacterial strains were identified in total, among them 20 strains were presented in larval gut, only 8 strains in pupae and 14 strains in adults were detected. Firmicutes bacteria, Bacillus sp., were the most dominant species in every life stage. 15 distinct bands were obtained from DGGE electrophoresis gel. The sequences blasted in GenBank database showed these bacteria belonged to six different genera. Phylogenetic analysis showed the sequences of the bacteria belonged to the Actinobacteri, Proteobacteria and Firmicutes. Serratia sp. in Proteobacteria was the most abundant species in larval gut. In pupae, unculturable bacteria were the most dominant species, and unculturable bacteria and Serratia sp. were the most dominant species in adults. Our study suggested that a combination of molecular and traditional culturing methods can be effectively used to analyze and to determine the diversity of gut microflora. These known bacteria may play important roles in development of P. xylostella.

  12. Heterotrophic bacteria abundances in Rodrigo de Freitas Lagoon (Rio de Janeiro, Brazil Abundância bacteriana heterotrófica na Lagoa Rodrigo de Freitas (Rio de Janeiro, Brasil

    Directory of Open Access Journals (Sweden)

    Alessandra M. Gonzalez

    2006-12-01

    Full Text Available The Rodrigo de Freitas Lagoon (RJ, Brazil is an important coastal ecosystem that has been submitted to an accelerated degradation process. The aim of this work was to determine the abundance and the spatial distribution of total heterotrophic (by flow cytometry and cultivated bacteria ("pour plate" method on R2A agar. Another objective was to evaluate the lagoon's influence on water quality of Ipanema and Leblon beaches. Physical and chemical data were acquired too. Sub-superficial water samples were taken monthly, from December 1999 to October 2000. On lagoon, the cultivated bacteria abundance varied from 6.9x10(5 to 5.0x10(7 CFU.100 mL-1. On Ipanema and Leblon beaches, this parameter yielded 1.4x10(5 and 2.8x10(6 CFU.100 mL-1, respectively. Total bacterial abundance varied from 2.9x10(7 to 3.2x10(7 cells.mL-1 on lagoon. On Ipanema and Leblon, this parameter yielded 8.7x10(6 and 1.1x10(7 cells.mL-1, respectively. Two sub-groups were determined with dominance of HNA cells. Samples were added latter to better understand the bacteria present on these environments. Bacterial abundance were analyzed only by flow cytometry and the results varied from 8.3x10(6 to 2.5x10(7 cells.mL-1 on lagoon. On the beach, this parameter yielded 6.9x10(6 cells. mL-1. Two bacterial sub-groups were also observed, with dominance of HNA on lagoon and LNA on the beach. The results showed that the Rodrigo de Freitas Lagoon is an eutrophic ecosystem where the bacterial populations and the physical and chemical parameters do not differ spatially. The data also confirmed that the outflow of the lagoon's polluted waters affect the sanitary conditions of Ipanema and Leblon beaches.A Lagoa Rodrigo de Freitas (RJ, Brasil é um importante ecossistema que vêm sendo submetido a um acelerado processo de degradação. O objetivo desse estudo foi determinar a abundância e a distribuição espacial das bactérias heterotróficas totais (citometria em fluxo e cultivadas ("pour plate

  13. Heterotrophic Bacterial Flora in Aquaculture Area around Xuejiadao

    Institute of Scientific and Technical Information of China (English)

    DU Zongjun; LI Yun; YU Dehua; WANG Xianghong; CHEN Jixiang; Robertson P.A.W.; Austin B.; XU Huaishu

    2002-01-01

    From Oct., 1999 to Oct., 2000, the heterotrophic bacterial flora in the aquaculture area around Xuejiadao wasinvestigated. The result shows that the populations of the heterotrophic bacteria are heavier in summer and autumn thanthose in winter and spring. The average populations in seawater, sediment, the surface of seaweed and the surface of fish are1.4 × 104cfu mL -1, 5.4 × 106cfu g 1, 1.5 × 106cfu g-1 and 1.8 × 103cfu cm 2, respectively. A total of 30l strains were isolated,among them 259 were Gram-negative. All the Gram-negative bacteria belong to 13 genera and some genera of Enterobacteri-aceae. The communities of bacteria are slightly different among the samples. In the body surface of fish, Genus vibrio isdominant. In the remaining samples, dominant genus is Aeromonas.

  14. Increased production of outer membrane vesicles by cultured freshwater bacteria in response to ultraviolet radiation.

    Science.gov (United States)

    Gamalier, Juliana P; Silva, Thiago P; Zarantonello, Victor; Dias, Felipe F; Melo, Rossana C N

    2017-01-01

    Secretion of membrane vesicles is an important biological process of both eukaryotic and prokaryotic cells. This process has been characterized in pathogenic bacteria, but is less clear in non-pathogenic bacteria from aquatic ecosystems. Here, we investigated, for the first time, the process of formation of outer membranes vesicles (OMVs), nanoscale vesicles extruded from the outer membrane (OM) of gram-negative bacteria, in cultures of freshwater bacteria after exposure or not to ultraviolet radiation (UVR) as an environmental stressor. Non-axenic cultures of freshwater bacteria isolated from a Brazilian aquatic ecosystem (Funil reservoir) were exposed or not to UVR (UVA+UVB) over a 3h period, during which cell density, viability and ultrastructure were analyzed. First, we showed that UVR induce bacterial death. UVR triggered significant negative effect on cell density after 3h of UVR treatment. This decrease was directly associated with cell death as revealed by a cell viability fluorescent probe that enables the distinction of live/dead bacteria. Transmission electron microscopy (TEM) revealed changes indicative of cell death after 3h of UVR exposure, with significant increase of damaged cells compared to the control group. Second, we demonstrated that gram-negative bacteria release OMVs during normal growth and after UVR exposure. OMVs were clearly identified as round, membrane-bound vesicles budding off from the bacterial OM as isolated or clustered vesicles or free in the extracellular medium. Remarkably, quantitative TEM analyses showed that bacteria respond to UVR with increased formation of OMVs. Moreover, while OMVs numbers per intact or damaged cell did not differ in the untreated group, UVR led to a higher vesiculation by bacteria in process of death. This means that degenerating bacteria release OMVs before lysis and that this secretion might be an adaptive/protective response to rapid changes in environmental conditions such as UV radiation. Copyright

  15. Distribution and species composition of planktonic luminous bacteria in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaiah, N.; Chandramohan, D.

    Distribution of the total viable heterotrophic bacteria and the luminous bacteria in the neretic and oceanic waters of the west coast of India was studied. Counts of viable heterotrophs fluctuated widely, generally with a decrease in their number...

  16. Effect of sampling time on the culturability of airborne fungi and bacteria sampled by filtration.

    Science.gov (United States)

    Durand, Kate T H; Muilenberg, Michael L; Burge, Harriet A; Seixas, Noah S

    2002-01-01

    Air sampling of bioaerosols by filtration may be preferable for many epidemiological studies because the methods can be used to collect personal samples for a full work-shift. There is some concern, however, that the viability of fungal spores and bacterial cells might be compromised by sampling for as long as a full shift. This study was designed to determine the effect of sampling up to 6 h on the viability (measured by culture) of airborne fungi and bacteria at composting facilities. Six side-by-side samples were collected in two locations at each of three composting facilities for 1 h at 2 l/m on polycarbonate filters. Two samples in each set were then capped while clean, HEPA-filtered air was drawn across two others for an additional 2 h and across the last two for an additional 5 h. Filters were washed and the samples were analyzed for culturable bacteria and fungi, and for total bacteria and fungi by microscopic counting. Concentrations ranged from 1.7 x 10(3) to 6.2 x 10(7) c.f.u./m3 of culturable fungi and 1.17 x 10(4) to 1.0 x 10(6) c.f.u./m3 of culturable bacteria. In linear models that included duration of sampling, location, and the interaction of location and sample duration, neither sample duration nor the interaction term were significant predictors of the logs of the concentrations of culturable fungi or bacteria or of the ratio of the logs of the culturable concentrations to total concentrations for fungi or bacteria. This suggests that increased sampling time does not affect the viability of the organisms commonly found in the air at composting facilities.

  17. Bacteria in non-woven textile filters for domestic wastewater treatment.

    Science.gov (United States)

    Spychała, Marcin; Starzyk, Justyna

    2015-01-01

    The objective of this study was preliminary identification of heterotrophic and ammonia oxidizing bacteria (AOB) cell concentration in the cross-sectional profile of geotextile filters for wastewater treatment. Filters of thicknesses 3.6 and 7.2 mm, made of non-woven textile TS20, were supplied with septic tank effluent and intermittently dosed and filtered under hydrostatic pressure. The cumulative loads of chemical oxygen demand (COD) and total solids were about 1.36 and 1.06 kg/cm2, respectively. The filters under analysis reached a relatively high removal efficiency for organic pollution 70-90% for biochemical oxygen demand (BOD5) and 60-85% for COD. The ammonia nitrogen removal efficiency level proved to be unstable (15-55%). Biomass samples for dry mass identification were taken from two regions: continuously flooded with wastewater and intermittently flooded with wastewater. The culturable heterotrophic bacteria were determined as colony-forming units (CFUs) on microbiological-selective media by means of the plate method. AOB and nitrite oxidizing bacteria (NOB) were examined using the FISH technique. A relatively wide range of heterotrophic bacteria was observed from 7.4×10(5)/cm2 to 3.8×10(6)/cm2 in geotextile layers. The highest concentration of heterotrophic bacteria (3.8×10(6)/cm2) was observed in the first layer of the textile filter. AOB were identified occasionally--about 8-15% of all bacteria colonizing the last filter layer, but occasionally much higher concentrations and ammonia nitrogen efficiency were achieved. Bacteria oxidizing nitrite to nitrate were not observed. The relation of total and organic fraction of biomass to culturable heterotrophic bacteria was also found.

  18. Acetic acid bacteria in traditional balsamic vinegar: phenotypic traits relevant for starter cultures selection.

    Science.gov (United States)

    Gullo, Maria; Giudici, Paolo

    2008-06-30

    This review focuses on acetic acid bacteria in traditional balsamic vinegar process. Although several studies are available on acetic acid bacteria ecology, metabolism and nutritional requirements, their activity as well as their technological traits in homemade vinegars as traditional balsamic vinegar is not well known. The basic technology to oxidise cooked grape must to produce traditional balsamic vinegar is performed by the so called "seed-vinegar" that is a microbiologically undefined starter culture obtained from spontaneous acetification of previous raw material. Selected starter cultures are the main technological improvement in order to innovate traditional balsamic vinegar production but until now they are rarely applied. To develop acetic acid bacteria starter cultures, selection criteria have to take in account composition of raw material, acetic acid bacteria metabolic activities, applied technology and desired characteristics of the final product. For traditional balsamic vinegar, significative phenotypical traits of acetic acid bacteria have been highlighted. Basic traits are: ethanol preferred and efficient oxidation, fast rate of acetic acid production, tolerance to high concentration of acetic acid, no overoxidation and low pH resistance. Specific traits are tolerance to high sugar concentration and to a wide temperature range. Gluconacetobacter europaeus and Acetobacter malorum strains can be evaluated to develop selected starter cultures since they show one or more suitable characters.

  19. Bacterial Diversity and Bioprospecting for Cold-Active Hydrolytic Enzymes from Culturable Bacteria Associated with Sediment from Nella Fjord, Eastern Antarctica

    Directory of Open Access Journals (Sweden)

    Bo Chen

    2011-01-01

    Full Text Available The diversity and cold-active hydrolytic enzymes of culturable bacteria associated with sandy sediment from Nella Fjord, Eastern Antarctica (69°22′6″ S, 76°21′45″ E was investigated. A total of 33 aerobic heterotrophic bacterial strains were isolated at 4 °C. These bacterial isolates could be sorted into 18 phylotypes based on the 16S rRNA gene sequence belonging to four phyla, namely Alphaproteobacteria, Gammaproteobacteria, Bacteroidetes and Actinobacteria. Only seven isolates were psychrophilic, 15 isolates were moderately psychrophilic, and 11 isolates were psychrotolerant. More than 72% of the isolates required sodium chloride to grow. Esterase, b-glucosidase and proteases activities at 4 °C were detected in more than 45% of the strains while approximately 21%, 15% and 12% of the strains possessed lipase, amylase and chitinase, respectively. These results indicate that a relatively high culturable bacterial diversity is present within marine sediment of Nella Fjord and it could serve as an ideal candidate region for bioprospecting.

  20. Bacterial diversity and bioprospecting for cold-active hydrolytic enzymes from culturable bacteria associated with sediment from Nella Fjord, Eastern Antarctica.

    Science.gov (United States)

    Yu, Yong; Li, Hui-Rong; Zeng, Yin-Xin; Chen, Bo

    2011-01-31

    The diversity and cold-active hydrolytic enzymes of culturable bacteria associated with sandy sediment from Nella Fjord, Eastern Antarctica (69°22'6″ S, 76°21'45″ E) was investigated. A total of 33 aerobic heterotrophic bacterial strains were isolated at 4 °C. These bacterial isolates could be sorted into 18 phylotypes based on the 16S rRNA gene sequence belonging to four phyla, namely Alphaproteobacteria, Gammaproteobacteria, Bacteroidetes and Actinobacteria. Only seven isolates were psychrophilic, 15 isolates were moderately psychrophilic, and 11 isolates were psychrotolerant. More than 72% of the isolates required sodium chloride to grow. Esterase, β-glucosidase and proteases activities at 4 °C were detected in more than 45% of the strains while approximately 21%, 15% and 12% of the strains possessed lipase, amylase and chitinase, respectively. These results indicate that a relatively high culturable bacterial diversity is present within marine sediment of Nella Fjord and it could serve as an ideal candidate region for bioprospecting.

  1. Interaction between Chlorella vulgaris and bacteria:interference and resource competition

    Institute of Scientific and Technical Information of China (English)

    QU Liang; WANG Renjun; ZHAO Peng; CHEN Ruinan; ZHOU Wenli; TANG Liuqing; TANG Xuexi

    2014-01-01

    Research of interaction mechanism between Chlorella vulgaris and two bacterial strains (Z-QD08 and Z-QS01) were conducted under laboratory conditions. Growth rates of bacteria and C. vulgaris were tested under co-culture conditions to evaluate the effects of concentrations of C. vulgaris and bacteria on their interactions. To test whether the availability of inorganic nutrients, vitamins and trace metals affects the interactions between C. vulgaris and bacteria, experiments were performed with or without the culture medium filtrate of C. vulgaris or bacteria. The results showed that the growth of C. vulgaris was promot-ed at low concentrations of bacteria (5×106 cells/ml), and expressed a positive correlation with the bacteria density, whereas opposite trend was observed for treatments with high bacteria density (10×106 cells/ml and 20×106 cells/ml). The growth rate of bacteria decreased with the increasing concentrations of C. vul-garis. The growth of bacteria Z-QD08 was inhibited by C. vulgaris through interference competition, while the mechanism for interaction between bacteria Z-QS01 and C. vulgaris was resource competition. The influence of cell density on the interaction between microalgae and bacteria was also discussed. These ex-periments confirm some elements of published theory on interactions between heterotrophic bacteria and microalgae and suggest that heterotrophic bacteria play an important role in the development of blooms in natural waters.

  2. Use of MALDI-TOF MS technique for rapid identification of bacteria from positive blood cultures

    Directory of Open Access Journals (Sweden)

    Sung Kuk Hong

    2014-01-01

    Full Text Available We evaluated the feasibility of same-day routine aerobic bacterial identification using the following procedures: Picking colonies from 4 and 6 h incubated subculture from positive blood culture bottle and analyzing them by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS. The matched identification rate of this procedure at the species level was 80.6% (141/175 for the 4-h cultures compared with overnight cultures and 90.9% (159/175 for the 6-h cultures. Thus, our technique provides an easy and rapid method for identification of aerobic bacteria in routine clinical microbiology laboratories.

  3. FT-IR microspectroscopy in rapid identification of bacteria in pure and mixed culture

    Science.gov (United States)

    Fontoura, Inglid; Belo, Ricardo; Sakane, Kumiko; Cardoso, Maria Angélica Gargione; Khouri, Sônia; Uehara, Mituo; Raniero, Leandro; Martin, Airton A.

    2010-02-01

    In recent years FT-IR microspectroscopy has been developed for microbiology analysis and applied successfully in pure cultures of microorganisms to rapidly identify strains of bacteria, yeasts and fungi. The investigation and characterization of microorganism mixed cultures is also of growing importance, especially in hospitals where it is common to poly-microbial infections. In this work, the rapid identification of bacteria in pure and mixed cultures was studied. The bacteria were obtained from the Institute Oswaldo Cruz culture collection at Brazil. Escherichia coli ATCC 10799 and Staphylococcus aureus ATCC 14456 were analyzed, 3 inoculations were examined in triplicate: Escherichia coli, Staphylococcus aureus and a mixed culture of them. The inoculations were prepared according to McFarland 0.5, incubated at 37 ° C for 6 hours, diluted in saline, placed in the CaF2 window and store for one hour at 50°C to obtain thin film. The measurement was performed by Spectrum Spotlight 400 (Perkin-Elmer) equipment in the range of 4000-900 cm-1, with 32 scans using a transmittance technique with point and image modes. The data were processed (baseline, normalization, calculation of first derivate followed by smoothing with 9 point using a Savitzky-Golay algorithm) and a cluster analysis were done by Ward's algorithm and an excellent discrimination between pure and mixed culture was obtained. Our preliminary results indicate that the FT-IR microspectroscopy associated with cluster analysis can be used to discriminate between pure and mixed culture.

  4. Phylogeny of culturable estuarine bacteria catabolizing riverine organic matter in the northern Baltic Sea.

    Science.gov (United States)

    Kisand, Veljo; Cuadros, Rocio; Wikner, Johan

    2002-01-01

    The objective of our study was to isolate and determine the phylogenetic affiliation of culturable estuarine bacteria capable of catabolizing riverine dissolved organic matter (RDOM) under laboratory conditions. Additions of RDOM consistently promoted the growth of estuarine bacteria in carbon-limited dilution cultures, with seasonal variation in growth rates and yields. At least 42 different taxa were culturable on solid agar media and, according to quantitative DNA-DNA hybridizations, constituted 32 to 89% of the total bacterial number in the enriched treatments. Five species in the Cytophaga-Flexibacter-Bacteroides group and one in the gamma-proteobacteria phylogenetic group (Marinomonas sp.) were numerically dominant during the stationary phase of the RDOM-enriched dilution cultures but not in the control cultures. Four of the isolates in Cytophaga-Flexibacter-Bacteroides group were putatively affiliated with the genus FLAVOBACTERIUM: All dominating isolates were determined to be new species based on comparison to the current databases. The same group of species dominated independently of the season investigated, suggesting a low diversity of bacteria catabolizing RDOM in the estuary. It also suggested a broad tolerance of the dominating species to seasonal variation in hydrography, chemistry, and competition with other species. Taken together, our results suggest that a limited group of bacteria, mainly in the Flavobacterium genus, played an important role in introducing new energy and carbon to the marine system in the northern Baltic Sea.

  5. Use of potato extract broth for culturing root-nodule bacteria.

    Science.gov (United States)

    Martyniuk, Stefan; Oroń, Jadwiga

    2011-01-01

    Liquid media containing potato extract and 1% of glucose or sucrose were used to culture root-nodule bacteria (rhizobia) in shaken Erlenmeyer flasks. For comparison, these bacteria were also cultured in yeast extract-mannitol broth (YEMB) as a standard medium. Proliferation of rhizobia was monitored by measuring optical densities (OD550) of the cultures and by plate counting of the viable cells (c.f.u) of the bacteria. In general, multiplication of the rhizobia in potato extract-glucose broth (PEGB) and potato extract-sucrose broth (PESB) was markedly faster, as indicated by higher values of OD550, than in YEMB. The numbers of R. leguminosarum by. vicae GGL and S. meliloti 330 in PEGB and PEGB were high and ranged from 1.2 x 10(10) to 4.9 x 10(10) mL(-1) after 48 h of incubation at 28 degrees C. B. japonicum B3S culture in PEGB contained 6.4 x 10(9) c.f.u. ml(-1) after 72 h of incubation. PEGB and YEMB cultures of the rhizobia were similar with respect to their beneficial effects on nodulation of the host-plants of these bacteria.

  6. Study of frequency of bacteria isolated from blood culture and their antibiotic susceptibility pattern in a university hospital in Tehran

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    Hoorieh Saderi

    2009-12-01

    Full Text Available Introduction: Determining frequency of bacteria, isolated from blood culture and their antibiotic susceptibility patterns, has epidemiological significance and can help in selecting empirical therapy. This study was aimed to assess, the frequency of bacteria isolated from blood culture of patients suspected to bacteremia and their antibiotic susceptibility patterns. Methods: Culture of blood and determination of antibiotic susceptibility was done by standard methods. In this study, a variety of isolated bacteria types, antibiotic susceptibility, as well as age, sex and type of admission of patients were analyzed in a university hospital from 21 March, 2006 to 20 March, 2007. Results: During one year, blood culture was done for 5116 patients and bacteria were isolated in 912 cases (17.8%. Three most frequently groups of bacteria in blood cultures of patients were non-fermentative gram negative bacteria (Pseudomonas and Acintobacter spp, coliforms (Escherichia coli and enterobacter and klebsiella spp. and coagulase negative staphylococci, respectively, which were isolated in 63.4%, 17.0% and 12.8% of patients, and constituted 93.2% of positive blood cultures. Higher resistance was shown in bacteria isolated from inpatients compare to outpatients. Conclusion: This study showed the influence of age, sex and type of admission (outpatient or inpatient in a variety of isolated bacteria in blood culture. The result of this study were the same as the other studies in Iran and other countries in respect of the variety of isolated bacteria and antibiotic susceptibility and show increase of antibiotic resistance in these bacteria.

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

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    F. Van Wambeke

    2007-10-01

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

  8. Diagnosis of Helicobacter pylori: comparison of an urease test, histological visualization of curved bacteria and culture

    OpenAIRE

    Francisco Hernández; Patrícia Rivera; Manuel Sigarán; Jorge Miranda

    1991-01-01

    Helicobacter pylori was investigated in 189 patients for culture, microscopic visualization of campylobacter-like organisms (CLO) and a ten minute urease test. In 136 (72%) the bacteria was isolated, and in 98 of them CLO were histologically detected. Specificity, sensitivity, positive and negative predictive values of microscopic visualization of CLO were: 0.77, 0.73, 0.97 and 0.51, respectively; 98 culture-positive patients were urease test positive. Specificity, sensitivity, positive and n...

  9. High-Level Culturability of Epiphytic Bacteria and Frequency of Biosurfactant Producers on Leaves

    OpenAIRE

    Burch, AY; Do, PT; Sbodio, A; Suslow, TV; Lindow, SE

    2016-01-01

    To better characterize the bacterial community members capable of biosurfactant production on leaves, we distinguished culturable biosurfactant-producing bacteria from nonproducers and used community sequencing to compare the composition of these distinct cultured populations with that from DNA directly recovered from leaves. Communities on spinach, romaine, and head lettuce leaves were compared with communities from adjacent samples of soil and irrigation source water. Soil communities were ...

  10. Current Perspectives on Viable but Non-Culturable (VBNC Pathogenic Bacteria

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    Thandavarayan eRamamurthy

    2014-07-01

    Full Text Available Under stress conditions, many species of bacteria enter into starvation mode of metabolism or a physiologically viable but non-culturable (VBNC state. Several human pathogenic bacteria have been reported to enter into the VBNC state under these conditions. The pathogenic VBNC bacteria cannot be grown using conventional culture media, although they continue to retain their viability and express their virulence. Though there have been debates on the VBNC concept in the past, several molecular studies have shown that not only VBNC state can be induced under in vitro conditions but also that resuscitation from this state is possible under appropriate conditions. The most notable advance in resuscitating VBNC bacteria is the discovery of resuscitation-promoting factor (Rpf, which is a bacterial cytokines found in both Gram-positive and Gram-negative organisms. VBNC state is a survival strategy adopted by the bacteria, which has important implication in several fields, including environmental monitoring, food technology and infectious disease management and hence it is important to investigate the association of bacterial pathogens under VBNC state and the water/foodborne outbreaks. In this review, we describe various aspects of VBNC bacteria, which include their proteomic and genetic profiles under the VBNC state, conditions of resuscitation, methods of detection, antibiotic resistance and observations on Rpf.

  11. Assemblage of benthic diatoms and culturable heterotrophs in shallow-water hydrothermal vent of the D. Joao de Castro Seamount, Azores in the Atlantic Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Raghukumar, C.; Mohandass, C.; Cardigos, F.; DeCosta, P.M.; Santos, R.S.; Colaco, A.

    of the yellow and white zones respectively) was added to sterile sea water with pine pollen 16 . Purified cultures of thraustochytrids were maintained in modified Vishniac agar medium containing 0.01% glucose, 0.01% peptone, 0.05% yeast extract, vitamin mix...

  12. Culturable associated-bacteria of the sponge Theonella swinhoei show tolerance to high arsenic concentrations

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    Ray eKeren

    2015-02-01

    Full Text Available Sponges are potent filter feeders and as such are exposed to high fluxes of toxic trace elements, which can accumulate in their body over time. Such is the case of the Red Sea sponge Theonella swinhoei, which has been shown to accumulate up to 8500 mg/Kg of the highly toxic element arsenic. T. swinhoei is known to harbor a multitude of sponge-associated bacteria, so it is hypothesized that the associated-bacteria will be tolerant to high arsenic concentration. This study also investigates the fate of the arsenic accumulated in the sponge to test if the associated-bacteria have an important role in the arsenic accumulation process of their host, since bacteria are key players in the natural arsenic cycle. Separation of the sponge to sponge cells and bacteria enriched fractions showed that arsenic is accumulated by the bacteria. Sponge-associated, arsenic-tolerant bacteria were cultured in the presence of 5 mM of either arsenate or arsenite (equivalent to 6150 mg/Kg arsenic, dry weight. The 54 isolated bacteria were grouped to 15 OTUs and isolates belonging to 12 OTUs were assessed for tolerance to arsenate at increased concentrations up to 100 mM. Eight of the 12 OTUs tolerated an order of magnitude increase in the concentration of arsenate, and some exhibited external biomineralization of arsenic-magnesium salts. The biomineralization of this unique mineral was directly observed in bacteria for the first time. These results may provide an explanation for the ability of the sponge to accumulate considerable amounts of arsenic. Furthermore arsenic-mineralizing bacteria can potentially be used for the study of bioremediation, as arsenic toxicity affects millions of people worldwide.

  13. Quick Estimation Model for the Concentration of Indoor Airborne Culturable Bacteria: An Application of Machine Learning

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    Zhijian Liu

    2017-07-01

    Full Text Available Indoor airborne culturable bacteria are sometimes harmful to human health. Therefore, a quick estimation of their concentration is particularly necessary. However, measuring the indoor microorganism concentration (e.g., bacteria usually requires a large amount of time, economic cost, and manpower. In this paper, we aim to provide a quick solution: using knowledge-based machine learning to provide quick estimation of the concentration of indoor airborne culturable bacteria only with the inputs of several measurable indoor environmental indicators, including: indoor particulate matter (PM2.5 and PM10, temperature, relative humidity, and CO2 concentration. Our results show that a general regression neural network (GRNN model can sufficiently provide a quick and decent estimation based on the model training and testing using an experimental database with 249 data groups.

  14. Quick Estimation Model for the Concentration of Indoor Airborne Culturable Bacteria: An Application of Machine Learning.

    Science.gov (United States)

    Liu, Zhijian; Li, Hao; Cao, Guoqing

    2017-07-30

    Indoor airborne culturable bacteria are sometimes harmful to human health. Therefore, a quick estimation of their concentration is particularly necessary. However, measuring the indoor microorganism concentration (e.g., bacteria) usually requires a large amount of time, economic cost, and manpower. In this paper, we aim to provide a quick solution: using knowledge-based machine learning to provide quick estimation of the concentration of indoor airborne culturable bacteria only with the inputs of several measurable indoor environmental indicators, including: indoor particulate matter (PM2.5 and PM10), temperature, relative humidity, and CO₂ concentration. Our results show that a general regression neural network (GRNN) model can sufficiently provide a quick and decent estimation based on the model training and testing using an experimental database with 249 data groups.

  15. VIABILITY AND ISOLATION OF MARINE-BACTERIA BY DILUTION CULTURE - THEORY, PROCEDURES, AND INITIAL RESULTS

    NARCIS (Netherlands)

    BUTTON, DK; SCHUT, F; QUANG, P; MARTIN, R; ROBERTSON, BR

    1993-01-01

    Dilution culture, a method for growing the typical small bacteria from natural aquatic assemblages, has been developed. Each of 11 experimental trials of the technique was successful. Populations are measured, diluted to a small and known number of cells, inoculated into unamended sterilized seawate

  16. BIOCHEMICAL CHARACTERISTICS OF LACTIC ACID PRODUCING BACTERIA AND PREPARATION OF CAMEL MILK CHEESE BY USING STARTER CULTURE

    OpenAIRE

    T. Ahmed and R. Kanwal

    2004-01-01

    Lactic acid bacteria (LAB) were isolated from camel milk by culturing the milk on specific media and pure culture was obtained by sub-culturing. Purification of culture was confirmed by Gram’s staining and identified by different biochemical tests. Camel milk contained lactic acid producing bacteria like Streptococci such as S. cremoris and S. lactis and Lactobacilli such as L. acidophilus. L. acidophilus grew more rapidly in camel milk than others as its growth was supported by camel milk...

  17. Salt stress induced lipid accumulation in heterotrophic culture cells of Chlorella protothecoides: Mechanisms based on the multi-level analysis of oxidative response, key enzyme activity and biochemical alteration.

    Science.gov (United States)

    Wang, Tao; Ge, Haiyan; Liu, Tingting; Tian, Xiwei; Wang, Zejian; Guo, Meijin; Chu, Ju; Zhuang, Yingping

    2016-06-20

    Salt stress as an effective stress factor that could improve the lipid content and lipid yield of glucose in the heterotrophic culture cells of Chlorella protothecoides was demonstrated in this study. The highest lipid content of 41.2% and lipid yield of 185.8mg/g were obtained when C. protothecoides was stressed under 30g/L NaCl condition at its late logarithmic growth phase. Moreover, the effects of salt and osmotic stress on lipid accumulation were comparatively analyzed, and it was found that the effects of NaCl and KCl stress had no significant differences at the same osmolarity level of 1150mOsm/kg with lipid contents of 41.7 and 40.8% as well as lipid yields of 192.9 and 186.8mg/g, respectively, whereas these results were obviously higher than those obtained under the iso-osmotic glycerol and sorbitol stresses. Furthermore, basing on the multi-level analysis of oxidative response, key enzyme activity and biochemical alteration, the superior performance of salt stress driving lipid over-synthesis was probably ascribed to the more ROS production as a result of additional ion effect besides the osmotic effect, subsequently mediating the alteration from carbohydrate storage to lipid accumulation in signal transduction process of C. protothecoides.

  18. Heterotrophic potential of Atribacteria from deep marine Antarctic sediment

    Science.gov (United States)

    Carr, S. A.; Orcutt, B.; Mandernack, K. W.; Spear, J. R.

    2015-12-01

    Bacteria belonging to the newly classified candidate phylum "Atribacteria" (formerly referred to as "OP9" and "JS1") are common in anoxic methane-rich sediments. However, the metabolic functions and biogeochemical role of these microorganisms in the subsurface remains unrealized due to the lack of pure culture representatives. This study observed a steady increase of Atribacteria-related sequences with increasing sediment depth throughout the methane-rich zone of the Adélie Basin, Antarctica (according to a 16S rRNA gene survey). To explore the functional potential of Atribacteria in this basin, samples from various depths (14, 25 and 97 meters below seafloor), were subjected to metagenomic sequencing. Additionally, individual cells were separated from frozen, unpreserved sediment for whole genome amplification. The successful isolation and sequencing of a single-amplified Atribacteria genome from these unpreserved sediments demonstrates a future use of single cell techniques with previously collected and frozen sediments. Our resulting single-cell amplified genome, combined with metagenomic interpretations, provides our first insights to the functional potential of Atribacteria in deep subsurface settings. As observed for non-marine Atribacteria, genomic analyses suggest a heterotrophic metabolism, with Atribacteria potentially producing fermentation products such as acetate, ethanol and CO2. These products may in turn support methanogens within the sediment microbial community and explain the frequent occurrence of Atribacteria in anoxic methane-rich sediments.

  19. Isolation of culturable endophytic bacteria from Moso bamboo (Phyllostachys edulis and 16S rDNA diversity analysis

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    Yuan Zong-Sheng

    2015-01-01

    Full Text Available We analyzed culturable endophytic bacteria from Moso bamboo (Phyllostachys edulis using traditional bacterial isolation and culture methods and then studied the colony characteristics and diversity with a 16S rDNA sequence analysis. We isolated 82 endophytic bacteria strains belonging to 47 species in 26 genera from the root, rhizome, stem and leaves of Moso bamboo species from populations on Wuyi Mountain, and in the Jiangle and Changting regions. There were significant differences in the composition of the culturable endophytic bacteria isolated from the different areas and from different tissues. The dominant bacteria strains from the Wuyi Mountain samples were Arthrobacter, Staphylococcus, Bacillus and Enterobacter, while the dominant bacteria from the Jiangle samples were Bacillus, Staphylococcus and Curtobacterium, and the dominant bacteria in the Changting samples were Alcaligenes, Pseudomonas, Staphylococcus and Bacillus. Our results demonstrate the abundant diversity of endophytic bacteria in Moso bamboo.

  20. Process for the lysis of a culture of lactic acid bacteria by means of a lysin, and uses of the resulting lysed culture

    NARCIS (Netherlands)

    Buist, Girbe; Venema, Gerard; Kok, Jan; Ledeboer, Aat M.

    1995-01-01

    The invention provides a process for the lysis of a culture of lactic acid bacteria, or a product containing such culture e.g. cheese, by means of a lysin through the in situ production of a homologous autolysin, or a heterologous autolysin obtainable from Gram-positive bacteria esp. from lactic aci

  1. Clinical identification of bacteria in human chronic wound infections: culturing vs. 16S ribosomal DNA sequencing

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    Rhoads Daniel D

    2012-11-01

    Full Text Available Abstract Background Chronic wounds affect millions of people and cost billions of dollars in the United States each year. These wounds harbor polymicrobial biofilm communities, which can be difficult to elucidate using culturing methods. Clinical molecular microbiological methods are increasingly being employed to investigate the microbiota of chronic infections, including wounds, as part of standard patient care. However, molecular testing is more sensitive than culturing, which results in markedly different results being reported to clinicians. This study compares the results of aerobic culturing and molecular testing (culture-free 16S ribosomal DNA sequencing, and it examines the relative abundance score that is generated by the molecular test and the usefulness of the relative abundance score in predicting the likelihood that the same organism would be detected by culture. Methods Parallel samples from 51 chronic wounds were studied using aerobic culturing and 16S DNA sequencing for the identification of bacteria. Results One hundred forty-five (145 unique genera were identified using molecular methods, and 68 of these genera were aerotolerant. Fourteen (14 unique genera were identified using aerobic culture methods. One-third (31/92 of the cultures were determined to be Staphylococcus aureus, Pseudomonas aeruginosa, and Enterococcus faecalis with higher relative abundance scores were more likely to be detected by culture as demonstrated with regression modeling. Conclusion Discordance between molecular and culture testing is often observed. However, culture-free 16S ribosomal DNA sequencing and its relative abundance score can provide clinicians with insight into which bacteria are most abundant in a sample and which are most likely to be detected by culture.

  2. In Vitro Cultivation of 'Unculturable' Oral Bacteria, Facilitated by Community Culture and Media Supplementation with Siderophores.

    Science.gov (United States)

    Vartoukian, Sonia R; Adamowska, Aleksandra; Lawlor, Megan; Moazzez, Rebecca; Dewhirst, Floyd E; Wade, William G

    2016-01-01

    Over a third of oral bacteria are as-yet-uncultivated in-vitro. Siderophores have been previously shown to enable in-vitro growth of previously uncultivated bacteria. The objective of this study was to cultivate novel oral bacteria in siderophore-supplemented culture media. Various compounds with siderophore activity, including pyoverdines-Fe-complex, desferricoprogen and salicylic acid, were found to stimulate the growth of difficult-to-culture strains Prevotella sp. HOT-376 and Fretibacterium fastidiosum. Furthermore, pyrosequencing analysis demonstrated increased proportions of the as-yet-uncultivated phylotypes Dialister sp. HOT-119 and Megasphaera sp. HOT-123 on mixed culture plates supplemented with siderophores. Therefore a culture model was developed, which incorporated 15 μg siderophore (pyoverdines-Fe-complex or desferricoprogen) or 150 μl neat subgingival-plaque suspension into a central well on agar plates that were inoculated with heavily-diluted subgingival-plaque samples from subjects with periodontitis. Colonies showing satellitism were passaged onto fresh plates in co-culture with selected helper strains. Five novel strains, representatives of three previously-uncultivated taxa (Anaerolineae bacterium HOT-439, the first oral taxon from the Chloroflexi phylum to have been cultivated; Bacteroidetes bacterium HOT-365; and Peptostreptococcaceae bacterium HOT-091) were successfully isolated. All novel isolates required helper strains for growth, implying dependence on a biofilm lifestyle. Their characterisation will further our understanding of the human oral microbiome.

  3. C isotope fractionation during heterotrophic activity driven carbonate precipitation

    Science.gov (United States)

    Balci, Nurgul; Demirel, Cansu

    2016-04-01

    Stable carbon isotopic fractionation during carbonate precipitation induced by environmentally enriched heterotrophic halophilic microorganims was experimentally investigated under various salinity (% 4.5, %8, %15) conditions at 30 °C. Halophilic heterotrophic microorganims were enriched from a hypersaline Lake Acigöl located in SW Turkey (Balci et al.,2015) and later used for the precipitation experiments (solid and liquid medium). The carbonate precipitates had relatively high δ13C values (-4.3 to -16.9 ‰) compared to the δ13C values of the organic compounds that ranged from -27.5 to -25.4 ‰. At salinity of 4.5 % δ13C values of carbonate ranged from -4.9 ‰ to -10.9 ‰ with a 13C-enrichment factor of +20 to +16 ‰ higher than the δ13C values of the associated DOC (-27.5) . At salinity 8 % δ13C values of carbonate ranged from -16.3 ‰ to -11.7 ‰ with a 13C-enrichment factor of+11.3 to+15.9 ‰ higher than the δ13C values of the associated DOC. The respected values for 15 % salinity ranged from -12.3 ‰ to -9.7 ‰ with a 13C-enrichment factor of +15.2 to+16.8 ‰ higher than the δ13C values of the associated DOC. The carbonate precipitates produced in the solid medium are more enriched in 13C relative to liquid culture experiments. These results suggest that the carbon in the solid was derived from both the bacterial oxidation of organic compounds in the medium and from the atmospheric CO2. A solid medium used in the experiments may have suppressed convective and advective mass transport favouring diffusion-controlled system. This determination suggests that the rate and equilibration of CO2 exchange with the atmosphere is the major control on C isotope composition of carbonate minerals precipitated in the experiments. Key words: Lake Acıgöl, halophilic bacteria, carbonate biomineralization, C isotopes References Nurgul Balci, Meryem Menekşe, Nevin Gül Karagüler, M. Şeref Sönmez,Patrick Meister 2015.Reproducing authigenic carbonate

  4. Diversity of endophytic bacteria of Dendrobium officinale based on culture-dependent and culture-independent methods

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    Cong Pei

    2017-01-01

    Full Text Available Culture-dependent and culture-independent methods were compared and evaluated in the study of the endophytic diversity of Dendrobium officinale. Culture-independent methods consisted of polymerase chain reaction–denaturing gradient gel electrophoresis (PCR-DGGE and metagenome methods. According to the results, differences were found between the three methods. Three phyla, namely Firmicutes, Proteobacteria, and Actinobacteria, were detected using the culture-dependent method, and two phyla, Firmicutes and Proteobacteria, were detected by the DGGE method. Using the metagenome method, four major phyla were determined, including Proteobacteria (76.54%, Actinobacteria (18.56%, Firmicutes (2.27%, and Bacteroidetes (1.56%. A distinct trend was obtained at the genus level in terms of the method and the corresponding number of genera determined. There were 449 genera and 16 genera obtained from the metagenome and DGGE methods, respectively, and only 7 genera were obtained through the culture-dependent method. By comparison, all the genera from the culture-dependent and DGGE methods were contained in the members determined using the metagenome method. Overall, culture-dependent methods are limited to ‘finding’ endophytic bacteria in plants. DGGE is an alternative to investigating primary diversity patterns; however, the metagenome method is still the best choice for determining the endophytic profile in plants. It is essential to use multiphasic approaches to study cultured and uncultured microbes.

  5. Algae-bacteria association inferred by 16S rDNA similarity in established microalgae cultures.

    Science.gov (United States)

    Schwenk, Dagmar; Nohynek, Liisa; Rischer, Heiko

    2014-06-01

    Forty cultivable, visually distinct bacterial cultures were isolated from four Baltic microalgal cultures Chlorella pyrenoidosa, Scenedesmus obliquus, Isochrysis sp., and Nitzschia microcephala, which have been maintained for several years in the laboratory. Bacterial isolates were characterized with respect to morphology, antibiotic susceptibility, and 16S ribosomal DNA sequence. A total of 17 unique bacterial strains, almost all belonging to one of three families, Rhodobacteraceae, Rhizobiaceae, and Erythrobacteraceae, were subsequently isolated. The majority of isolated bacteria belong to Rhodobacteraceae. Literature review revealed that close relatives of the bacteria isolated in this study are not only often found in marine environments associated with algae, but also in lakes, sediments, and soil. Some of them had been shown to interact with organisms in their surroundings. A Basic Local Alignment Search Tool study indicated that especially bacteria isolated from the Isochrysis sp. culture were highly similar to microalgae-associated bacteria. Two of those isolates, I1 and I6, belong to the Cytophaga-Flavobacterium-Bacteroides phylum, members of which are known to occur in close communities with microalgae. An UniFrac analysis revealed that the bacterial community of Isochrysis sp. significantly differs from the other three communities.

  6. Size-resolved culturable airborne bacteria sampled in rice field, sanitary landfill, and waste incineration sites.

    Science.gov (United States)

    Heo, Yongju; Park, Jiyeon; Lim, Sung-Il; Hur, Hor-Gil; Kim, Daesung; Park, Kihong

    2010-08-01

    Size-resolved bacterial concentrations in atmospheric aerosols sampled by using a six stage viable impactor at rice field, sanitary landfill, and waste incinerator sites were determined. Culture-based and Polymerase Chain Reaction (PCR) methods were used to identify the airborne bacteria. The culturable bacteria concentration in total suspended particles (TSP) was found to be the highest (848 Colony Forming Unit (CFU)/m(3)) at the sanitary landfill sampling site, while the rice field sampling site has the lowest (125 CFU/m(3)). The closed landfill would be the main source of the observed bacteria concentration at the sanitary landfill. The rice field sampling site was fully covered by rice grain with wetted conditions before harvest and had no significant contribution to the airborne bacteria concentration. This might occur because the dry conditions favor suspension of soil particles and this area had limited personnel and vehicle flow. The respirable fraction calculated by particles less than 3.3 mum was highest (26%) at the sanitary landfill sampling site followed by waste incinerator (19%) and rice field (10%), which showed a lower level of respiratory fraction compared to previous literature values. We identified 58 species in 23 genera of culturable bacteria, and the Microbacterium, Staphylococcus, and Micrococcus were the most abundant genera at the sanitary landfill, waste incinerator, and rice field sites, respectively. An antibiotic resistant test for the above bacteria (Micrococcus sp., Microbacterium sp., and Staphylococcus sp.) showed that the Staphylococcus sp. had the strongest resistance to both antibiotics (25.0% resistance for 32 microg ml(-1) of Chloramphenicol and 62.5% resistance for 4 microg ml(-1) of Gentamicin).

  7. Isolation of lactic acid bacteria with potential protective culture characteristics from fruits

    Science.gov (United States)

    Hashim, Nurul Huda; Sani, Norrakiah Abdullah

    2015-09-01

    Lactic acid bacteria are also known as beneficial microorganisms abundantly found in fermented food products. In this study, lactic acid bacteria were isolated from fresh cut fruits obtained from local markets. Throughout the isolation process from 11 samples of fruits, 225 presumptive lactic acid bacteria were isolated on MRS agar medium. After catalase and oxidase tests, 149 resulted to fit the characteristics of lactic acid bacteria. Further identification using Gram staining was conducted to identify the Gram positive bacteria. After this confirmation, the fermentation characteristics of these isolates were identified. It was found that 87 (58.4%) isolates were heterofermentative, while the rest of 62 (41.6%) are homofermentative lactic acid bacteria. Later, all these isolates were investigated for the ability to inhibit growth of Staphylococcus aureus using agar spot assay method. Seven (4.7%) isolates showed strong antagonistic capacity, while 127 (85.2%) and 8 (5.4%) isolates have medium and weak antagonistic capacity, respectively. The other 7 (4.7%) isolates indicated to have no antagonistic effect on S. aureus. Results support the potential of LAB isolated in this study which showed strong antagonistic activity against S. aureus may be manipulated to become protective cultures in food products. While the homofermentative or heterofermentative LAB can be utilized in fermentation of food and non-food products depending on the by-products required during the fermentation.

  8. STUDY ON INACTIVATION OF HETEROTROPHIC BACTERIA IN THE CIRCULATING COOLING WATER SYSTEM OF POWER PLANT BY SWEET PULSED MAGNETIC FIELD%扫频脉冲磁场对电厂循环冷却水中异养菌的灭活研究

    Institute of Scientific and Technical Information of China (English)

    武红梅; 刘智安; 常英; 薛金英; 刘洋; 周斐博

    2011-01-01

    The effect of sweep pulsed magnetic field on heterotrophic bacteria of power plant circulating cooling water was studied and the inactivation key factors were analyzed.It was found that pulsed magnetic field has an inactivated role in heterotrophic bacteria.The efficiency depends on the frequency and output voltage.The inactivated rate of magnetic field is increased with the increasing of the temperature and the single magnetic treatment time.With the sweep pulse magnetic field 100~1 000 Hz,the single magnetic treatment time 15s,output voltage 3V,temperature 45℃ the inactivated rate is 78.8%.%研究了扫频脉冲磁场对电厂循环冷却水中异养菌的影响,并对灭活关键因素进行了分析。实验结果表明,脉冲磁场对电厂循环冷却水中的异养菌有灭活作用。灭活率对频率和输出电压具有选择性,并且随着作用时间和温度的升高而升高。在扫频范围100~1 000Hz、输出电压3 V、单次作用时间为15 s,温度45℃时,异养菌灭活率可达78.8%。

  9. Characterization of culturable bacteria isolated from the cold-water coral Lophelia pertusa

    Science.gov (United States)

    Galkiewicz, Julia P.; Pratte, Zoe A.; Gray, Michael A.; Kellogg, Christina A.

    2011-01-01

    Microorganisms associated with corals are hypothesized to contribute to the function of the host animal by cycling nutrients, breaking down carbon sources, fixing nitrogen, and producing antibiotics. This is the first study to culture and characterize bacteria from Lophelia pertusa, a cold-water coral found in the deep sea, in an effort to understand the roles that the microorganisms play in the coral microbial community. Two sites in the northern Gulf of Mexico were sampled over 2 years. Bacteria were cultured from coral tissue, skeleton, and mucus, identified by 16S rRNA genes, and subjected to biochemical testing. Most isolates were members of the Gammaproteobacteria, although there was one isolate each from the Betaproteobacteria and Actinobacteria. Phylogenetic results showed that both sampling sites shared closely related isolates (e.g. Pseudoalteromonas spp.), indicating possible temporally and geographically stable bacterial-coral associations. The Kirby-Bauer antibiotic susceptibility test was used to separate bacteria to the strain level, with the results showing that isolates that were phylogenetically tightly grouped had varying responses to antibiotics. These results support the conclusion that phylogenetic placement cannot predict strain-level differences and further highlight the need for culture-based experiments to supplement culture-independent studies.

  10. Study of frequency of bacteria isolated from blood culture and their antibiotic susceptibility pattern in a university hospital in Tehran

    OpenAIRE

    Hoorieh Saderi; Ali akbar Karimi; Marzieh Loni

    2009-01-01

    Introduction: Determining frequency of bacteria, isolated from blood culture and their antibiotic susceptibility patterns, has epidemiological significance and can help in selecting empirical therapy. This study was aimed to assess, the frequency of bacteria isolated from blood culture of patients suspected to bacteremia and their antibiotic susceptibility patterns. Methods: Culture of blood and determination of antibiotic susceptibility was done by standard methods. In this study, a variety ...

  11. Antioxidant Activity of Peptides from Fermented Milk with Mix Culture of Lactic Acid Bacteria and Yeast

    Directory of Open Access Journals (Sweden)

    Yun Li

    2015-02-01

    Full Text Available The aim of the present study is to investigate the production of antioxidant peptides during milk fermentation with co-culture of Lactic Acid Bacteria (LAB and yeast. Five LAB strains, previously screened with higher hydrolysis activity and Debaryomyces hansenii H2 which isolated from Tibet kefir were used in the study. The peptides separated from fermented milk were analysed antioxidant activity with DPPH radical scavenging, hydroxyl radical scavenging, chelation of metal ions and reducing power assays. The growth of Streptococcus. thermophilus Lactobacillus. delbrueckii ssp. bulgaricus and Lactococcus. lactis was enhanced with co-cultures and L. acidophilus was inhibited in co-culture with yeast. In co-culture with yeast, a significant decrease of the acidity was observed among all the fermentation and the pH reached higher values than in single LAB cultures. Except for L.delbrueckii ssp. bulgaricus, there was no significant difference of protein hydrolysis with other test LAB strains between co-culture and single culture. The co-incubation of LAB with the yeast developed a stronger antioxidant activity in DPPH radical and hydroxyl radical scavenging and no significant (p>0.05 difference in chelation of metal ions. The reducing power of L.delbrueckii ssp. bulgaricus and L. helveticus in co-culture was significant higher than those of single culture.

  12. Grazing on autotrophic and heterotrophic picoplankton by ciliates isolated from Lake Kinneret, Israel

    NARCIS (Netherlands)

    Hadas, O.; Malinsky-Rushansky, N.; Pinkas, R.; Cappenberg, T.E.

    1998-01-01

    The rates of ingestion of three ciliates (Colpoda steinii, Cyclidium sp. and Stylonichia sp.) on fluorescently labeled heterotrophic bacteria, picocyanobacteria (Synechococcus P, CN) and a picoeukaryote isolated from Lake Kinneret were measured. Uptake values were 930, 35 and 1210 bacteria ciliate (

  13. Role in Cheese Flavour Formation of Heterofermentative Lactic Acid Bacteria from Mesophilic Starter Cultures

    DEFF Research Database (Denmark)

    Pedersen, Thomas Bæk

    -starters including strains from our culture collection were used throughout the project. Initially selected strains were screened for enzyme activities involved in cheese flavour formation after growth in a cheese based medium (CBM) and in a nutrient rich growth medium (MRS). The Leuconostoc strains had low...... the heterofermentative bacteria grew and were established well. The biodiversity of heterofermentative bacteria in DL-starters was examined using pulsed field gel electrophoresis (PFGE) and the strains were characterized with 16s rRNA sequencing and carbohydrate fermentation. The sugar fermentation results indicated...... with plant isolates, the ability to ferment citrate and lacked several genes involved in the fermentation of complex carbohydrates. The presented research in this thesis has gained insight in to the role of heterofermentative lactic acid bacteria in cheese flavour formation. The traditional DL...

  14. Diversity of cultured bacteria from the perennial ice block of Scarisoara Ice Cave, Romania

    Directory of Open Access Journals (Sweden)

    Corina Iţcuş

    2016-01-01

    Full Text Available Cave ice ecosystems represent a poorly investigated glacial environment. Diversity of cave ice bacteria and their distribution in perennial ice deposits of this underground glacial habitat could constitute a proxy for microbial response to climatic and environmental changes. Scarisoara Ice Cave (Romania hosts one of the oldest and largest cave ice blocks worldwide. Here we report on cultured microbial diversity of recent, 400, and 900 years-old perennial ice from this cave, representing the first characterization of a chronological distribution of cave-ice bacteria. Total cell density measured by SYBR Green I epifluorescence microscopy varied in the 2.4 x 104 – 2.9 x 105 cells mL-1 range. The abundance of cultured bacteria (5 x 102 – 8 x 104 CFU mL-1 representing 0.3-52% of the total cell number decreased exponentially with the ice age, and was higher in organic rich ice sediments. Cultivation at 4˚C and 15˚C using BIOLOG EcoPlates revealed a higher functional diversity of cold-active bacteria, dependent on the age, sediment content and physicochemical properties of the ice. The composition dissimilarity of ice microbiota across the ice block was confirmed by growth parameter variations when cultivated in different liquid media at low and high temperatures. PCR-DGGE and sequencing of bacterial 16S rRNA gene fragments from the cultured ice samples led to the identification of 77 bacterial amplicons belonging to Gammaproteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria, showing variation in distribution across the ice layers. Several identified OTUs were homologous to those identified in other glacial and karst environments and showed partial conservation across the ice block. Moreover, our survey provided a glimpse on the cave-ice hosted bacteria as putative biomarkers for past climate and environmental changes.

  15. Occurrence of Aerobic and Anaerobic Bacteria in the Consumer End of a Water Distribution System.

    Science.gov (United States)

    Hoca, Süleyman; Üstüntürk-Onan, Miray; Ilhan-Sungur, Esra

    2017-07-01

      In this study, mixed species biofilm formation including sulphate-reducing bacteria (SRB) on polypropylene surface and bacteriology of network water were investigated in a model water distribution system during a nine-month period. Water and biofilm samples were analyzed for the enumeration of aerobic heterotrophic bacteria (AHB), anaerobic heterotrophic bacteria (ANHB) and SRB. The number of live/dead bacteria was also analyzed by epifluorescence microscopy. In addition, extracellular polysaccharide substances (EPS) extraction, carbohydrate analysis and scanning electron microscope observation were performed. A biofilm with heterogeneous structure formed on the polypropylene surface of the model water distribution system. Live/dead staining data indicated that biofilm matured in the first month. It was observed that especially AHB entered into a viable but not culturable state because of the temperature decrease. It was also noted that temperature is an important environmental factor especially for planktonic SRB. The quantity of carbohydrate significantly decreased according to the temperature.

  16. Anaerobic bacteria grow within Candida albicans biofilms and induce biofilm formation in suspension cultures.

    Science.gov (United States)

    Fox, Emily P; Cowley, Elise S; Nobile, Clarissa J; Hartooni, Nairi; Newman, Dianne K; Johnson, Alexander D

    2014-10-20

    The human microbiome contains diverse microorganisms, which share and compete for the same environmental niches. A major microbial growth form in the human body is the biofilm state, where tightly packed bacterial, archaeal, and fungal cells must cooperate and/or compete for resources in order to survive. We examined mixed biofilms composed of the major fungal species of the gut microbiome, Candida albicans, and each of five prevalent bacterial gastrointestinal inhabitants: Bacteroides fragilis, Clostridium perfringens, Escherichia coli, Klebsiella pneumoniae, and Enterococcus faecalis. We observed that biofilms formed by C. albicans provide a hypoxic microenvironment that supports the growth of two anaerobic bacteria, even when cultured in ambient oxic conditions that are normally toxic to the bacteria. We also found that coculture with bacteria in biofilms induces massive gene expression changes in C. albicans, including upregulation of WOR1, which encodes a transcription regulator that controls a phenotypic switch in C. albicans, from the "white" cell type to the "opaque" cell type. Finally, we observed that in suspension cultures, C. perfringens induces aggregation of C. albicans into "mini-biofilms," which allow C. perfringens cells to survive in a normally toxic environment. This work indicates that bacteria and C. albicans interactions modulate the local chemistry of their environment in multiple ways to create niches favorable to their growth and survival. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Combined therapy of Salmonella infection in chickens by antimicrobial agents followed by cultured cecal bacteria.

    Science.gov (United States)

    Seuna, E; Schneitz, C; Nurmi, E

    1980-06-01

    Week-old chickens infected with Salmonella infantis when one day old were treated with antimicrobial drugs either given alone or followed by peroral inoculation of bacterial culture. The bacteria were derived from the cecal contents of adult chickens. The antimicrobial drugs used were: neomycin, neomycin plus oxytetracycline, neomycin plus polymyxin, and sulfadiazine plus trimethoprim. The combined therapy with oxytetracycline plus neomycin and bacterial culture seemed to be the most effective, although the efficacy varied between the parallel trials. Sulfadiazine plus trimethoprim followed by treatment with the bacterial culture decreased the infection rate. The bacterial culture alone also had a slight anti-salmonella effect. When only antimicrobials were given, salmonellae rapidly reappeared in the intestines when the therapy was stopped.

  18. Solid Medium for Culturing Black Smoker Bacteria at Temperatures to 120°C

    OpenAIRE

    Deming, Jody W.; Baross, John A.

    1986-01-01

    A solid, highly thermostable medium, based on the new gelling agent GELRITE, was devised to facilitate the culturing of extremely thermophilic microorganisms from submarine hydrothermal vents. The medium remained solid at temperatures to 120°C at vapor pressures and hydrostatic pressures to 265 atm. It proved useful to its maximum tested limits in isolating colonies of black smoker bacteria from hydrothermal fluids recently collected at the Juan de Fuca Ridge in the Pacific Ocean.

  19. Pathogenesis of Human Enterovirulent Bacteria: Lessons from Cultured, Fully Differentiated Human Colon Cancer Cell Lines

    Science.gov (United States)

    Liévin-Le Moal, Vanessa

    2013-01-01

    SUMMARY Hosts are protected from attack by potentially harmful enteric microorganisms, viruses, and parasites by the polarized fully differentiated epithelial cells that make up the epithelium, providing a physical and functional barrier. Enterovirulent bacteria interact with the epithelial polarized cells lining the intestinal barrier, and some invade the cells. A better understanding of the cross talk between enterovirulent bacteria and the polarized intestinal cells has resulted in the identification of essential enterovirulent bacterial structures and virulence gene products playing pivotal roles in pathogenesis. Cultured animal cell lines and cultured human nonintestinal, undifferentiated epithelial cells have been extensively used for understanding the mechanisms by which some human enterovirulent bacteria induce intestinal disorders. Human colon carcinoma cell lines which are able to express in culture the functional and structural characteristics of mature enterocytes and goblet cells have been established, mimicking structurally and functionally an intestinal epithelial barrier. Moreover, Caco-2-derived M-like cells have been established, mimicking the bacterial capture property of M cells of Peyer's patches. This review intends to analyze the cellular and molecular mechanisms of pathogenesis of human enterovirulent bacteria observed in infected cultured human colon carcinoma enterocyte-like HT-29 subpopulations, enterocyte-like Caco-2 and clone cells, the colonic T84 cell line, HT-29 mucus-secreting cell subpopulations, and Caco-2-derived M-like cells, including cell association, cell entry, intracellular lifestyle, structural lesions at the brush border, functional lesions in enterocytes and goblet cells, functional and structural lesions at the junctional domain, and host cellular defense responses. PMID:24006470

  20. Detection, isolation, and preliminary characterization of bacteria contaminating plant tissue cultures

    Directory of Open Access Journals (Sweden)

    Monika Kałużna

    2014-01-01

    Full Text Available In order to limit the contamination problem in plant tissue cultures experiments on selection of media suitable for detection and isolation of bacteria contaminating plant tissue explants, and preliminary characterization of isolates were made. In the first experiment aiming at detection of bacteria in plant explants four strains representing genera most often occurring at our survey of plant tissue cultures, and earlier isolated and identified (Bacillus, Methylobacterium, Pseudomonas and Xanthomonas were streaked on five bacteriological media (NA, King B, K, R2A and 523 and on the medium used for plant culture initiation – ½ MS with milk albumin (IM. All strains grew on all media but on K and IM at the slowest rate and on 523 medium at the fastest. The IM medium proved to be useful for immediate bacteria detection at the initial stage of culture. In the second experiment, aiming at characterization of isolates on the basis of colony growth and morphology 14 strains (Agrobacterium, Bacillus, Curtobacterium, Flavobacterium, Lactobacillus, Methylobacterium – 2 strains Mycobacterium, Paenibacillus, Plantibacterium, Pseudomonas, Stenotrophomonas, Xanthomonas, and species Serratia marcescens were streaked on five microbiological media: KB, NBY, YDC, YNA and YPGA. All strains grew on all those media but at different rates. The only exception was the strain of Lactobacillus spp., which did not grow on King B medium. This medium allowed the detection of such characteristic traits as fluorescence (Pseudomonas and secretion of inclusions (Stenotrophomonas. The third experiment was focussed on assessment of the sensitivity of detection of specific bacteria in pure cultures and in plant tis- sue cultures using standard PCR and BIO-PCR techniques with genus specific primers and 2 methods of DNA isolation. Results showed that the use of Genomic Mini kit enabled an increase of the sensitivity by 100 times as compared to extraction of DNA by boiling

  1. Isolation and identification of culturable bacteria from honeydew of whitefly, Bemisia tabaci (G. (Hemiptera: Aleyrodidae

    Directory of Open Access Journals (Sweden)

    Roopa H.K.

    2014-12-01

    Full Text Available Bemisia tabaci (G. is an important pest and a vector of Gemini viruses infecting plants. During the process of feeding B. tabaci excretes honeydew which is rich in nutrients, and an excellent medium for microbial growth. Recent report proved that volatile emitted by the honeydew associated bacteria of aphid, Acyrthosiphon pisum Harris was involved in natural enemy calling. Thus understanding the honeydew associated bacteria is of paramount importance from the non-chemical method of insect pest management. In this perspective, very less information is available on bacteria associated with the honeydew excreted by B. tabaci. Therefore, in the present study we have isolated and characterized three culturable bacteria from the honeydew of B. tabaci viz. Bacillus endophyticus, Bacillus niacini and Roseomonas species by employing 16Sr DNA BLASTx analyses which revealed that both B. endophyticus and B. niacini had high similarity (>99% to the respective species, while Roseomonas sp. showed only 95% similarity to the existing Roseomonas sp. specificity of honeydew association of Roseomonas sp. was confirmed by developing specific primers as this genus is reported from immunocompromised persons and recently from ticks and mites. The present study also indicated the possible host-plant origin of these honeydew associated bacteria.

  2. Isolation and identification of culturable bacteria from honeydew of whitefly, Bemisia tabaci (G.) (Hemiptera: Aleyrodidae).

    Science.gov (United States)

    H K, Roopa; K B, Rebijith; R, Asokan; Mahmood, Riaz; N K, Krishna Kumar

    2014-12-01

    Bemisia tabaci (G.) is an important pest and a vector of Gemini viruses infecting plants. During the process of feeding B. tabaci excretes honeydew which is rich in nutrients, and an excellent medium for microbial growth. Recent report proved that volatile emitted by the honeydew associated bacteria of aphid, Acyrthosiphon pisum Harris was involved in natural enemy calling. Thus understanding the honeydew associated bacteria is of paramount importance from the non-chemical method of insect pest management. In this perspective, very less information is available on bacteria associated with the honeydew excreted by B. tabaci. Therefore, in the present study we have isolated and characterized three culturable bacteria from the honeydew of B. tabaci viz. Bacillus endophyticus, Bacillus niacini and Roseomonas species by employing 16Sr DNA BLASTx analyses which revealed that both B. endophyticus and B. niacini had high similarity (> 99%) to the respective species, while Roseomonas sp. showed only 95% similarity to the existing Roseomonas sp. specificity of honeydew association of Roseomonas sp. was confirmed by developing specific primers as this genus is reported from immunocompromised persons and recently from ticks and mites. The present study also indicated the possible host-plant origin of these honeydew associated bacteria.

  3. Enhancing the culturability of bacteria from the gastrointestinal tract of farmed adult turbot Scophthalmus maximus

    Science.gov (United States)

    Xing, Mengxin; Hou, Zhanhui; Qu, Yanmei; Liu, Bin

    2014-03-01

    Eighteen agar media were tested for the culture of gut-associated bacteria from farmed adult turbot ( Scophthalmus maximus), including 16 agar media with or without 1% gastrointestinal (GI) supernatant, or with 2% or 4% GI supernatant. A total of 1 711 colonies were analyzed and 24 operational taxonomic units (OTUs) were identified. The greatest bacterial diversity was isolated on Zobell 2216E/Zobell 2216E+ agar media, whereas MRS/MRS+ agar media produced a low diversity of colonies. Agar media with GI supernatant (1%, 2%, or 4%) showed increased diversity and yielded different profiles of OTUs from the corresponding original media, suggesting that GI supernatant provides substances that enhance the culture efficiency of bacteria from the turbot GI tract. The large majority of the colonies (82%) were γ-Proteobacteria, whereas 15.6% and 2.4% of colonies were Firmicutes and Actinobacteria, respectively. At the genus level, 49.4% of all colonies were assigned to Vibrio. Other potential pathogens, including Pseudomonas, Photobacterium, and Enterobacter, and potential probiotics, including Bacillus, Paenibacillus, and Pseudomonas, were also isolated on agar media. Most cultured bacteria belonged to species that were first described in the turbot GI tract. The impact of these species on turbot physiology and health should be investigated further.

  4. PCR identification of bacteria in blood culture does not fit the daily workflow of a routine microbiology laboratory.

    Science.gov (United States)

    Karumaa, Santra; Kärpänoja, Pauliina; Sarkkinen, Hannu

    2012-03-01

    We have evaluated the GenoType blood culture assay (Hain Lifescience, Nehren, Germany) for the identification of bacteria in 233 positive blood cultures and assessed its suitability in the workflow of a routine microbiology laboratory. In 68/233 (29.2%) samples, the culture result could not be confirmed by the GenoType assay due to a lack of primers in the test, multiple organisms in the sample, or inconsistency with respect to the identification by culture. Although the GenoType blood culture assay gives satisfactory results for bacteria for which primers are available, there are difficulties in applying the test in the routine microbiology laboratory.

  5. Flow cytometric viability assessment of lactic acid bacteria starter cultures produced by fluidized bed drying.

    Science.gov (United States)

    Bensch, Gerald; Rüger, Marc; Wassermann, Magdalena; Weinholz, Susann; Reichl, Udo; Cordes, Christiana

    2014-06-01

    For starter culture production, fluidized bed drying is an efficient and cost-effective alternative to the most frequently used freeze drying method. However, fluidized bed drying also poses damaging or lethal stress to bacteria. Therefore, investigation of impact of process variables and conditions on viability of starter cultures produced by fluidized bed drying is of major interest. Viability of bacteria is most frequently assessed by plate counting. While reproductive growth of cells can be characterized by the number of colony-forming units, it cannot provide the number of viable-but-nonculturable cells. However, in starter cultures, these cells still contribute to the fermentation during food production. In this study, flow cytometry was applied to assess viability of Lactobacillus plantarum starter cultures by membrane integrity analysis using SYBR®Green I and propidium iodide staining. The enumeration method established allowed for rapid, precise and sensitive determination of viable cell concentration, and was used to investigate effects of fluidized bed drying and storage on viability of L. plantarum. Drying caused substantial membrane damage on cells, most likely due to dehydration and oxidative stress. Nevertheless, high bacterial survival rates were obtained, and granulates contained in the average 2.7 × 10(9) viable cells/g. Furthermore, increased temperatures reduced viability of bacteria during storage. Differences in results of flow cytometry and plate counting suggested an occurrence of viable-but-nonculturable cells during storage. Overall, flow cytometric viability assessment is highly feasible for rapid routine in-process control in production of L. plantarum starter cultures, produced by fluidized bed drying.

  6. Characteristics of spatial and temporal distribution of bacteria in cage culture areas of Dapeng' ao Cove in spring%大鹏澳网箱养殖区春季细菌的时空分布特征

    Institute of Scientific and Technical Information of China (English)

    朱志红; 林钦; 黄洪辉

    2011-01-01

    This paper is about the first ecological survey of s in the Daya Bay in Apr. of 2008, focused on the distribution of heterotrophic bacteria and Vibrio in the water and sediment as well as the relationship with the environmental factors. The results showed that the concentration of heterotrophic bacteria in the water was higher in the culture area than that in the control area with significant differences in the level of α = 0.01. The heterotrophic bacteria concent ration in the culture area was 11 times higher than that in the control area in bottom mud. The vertical distribution of the heterotrophic bacteria concentration in the water was higher in the sea surface than that in the sea bottom, with the significant differences in the level of α =0.05. Compared to the water, heterotrophic bacteria content was very high in the sediments, come up to 1.1 × 107 cfu/g. The horizontal distribution of Vibrio content in the water was higher in the culture area than that in the control area with the significant differences in the level of α =0.05. The horizontal content distribution of Vibrio in bottom mud is in the culture area > in the control area with the significant differences in the level of α =0.01.The vertical distribution of Vibrio concentration in the water was higher in the sea surface than that in the sea bottom, with the significant differences in the level of α =0.01. Vibrio concentration in the sediments was as high as 1.0 × 107 cfu/g. The relationship among, temperature,salinity,the value of DO were discussed. The result showed that the concentration of heterotrophic bacteria was positively correlated with temperature ( r = 0. 843 ,p = 0. 035 ), but negative correlated with salinity and the value of DO( r = -0. 737,p = O. 095; r = -0. 224 ,p = 0. 670. There was a significant positive correlation between the Vibrio concentration and temperature ( r = 0. 821 ,p = O. 045 ), a negative correlation between Vibrio concentration and salinity( r = - 0. 860

  7. Indirect Interspecies Regulation: Transcriptional and Physiological Responses of a Cyanobacterium to Heterotrophic Partnership

    Science.gov (United States)

    McClure, Ryan S.; Thiel, Vera; Sadler, Natalie C.; Kim, Young-Mo; Chrisler, William B.; Hill, Eric A.; Romine, Margaret F.; Jansson, Janet K.; Fredrickson, Jim K.; Beliaev, Alexander S.

    2017-01-01

    ABSTRACT The mechanisms by which microbes interact in communities remain poorly understood. Here, we interrogated specific interactions between photoautotrophic and heterotrophic members of a model consortium to infer mechanisms that mediate metabolic coupling and acclimation to partnership. This binary consortium was composed of a cyanobacterium, Thermosynechococcus elongatus BP-1, which supported growth of an obligate aerobic heterotroph, Meiothermus ruber strain A, by providing organic carbon, O2, and reduced nitrogen. Species-resolved transcriptomic analyses were used in combination with growth and photosynthesis kinetics to infer interactions and the environmental context under which they occur. We found that the efficiency of biomass production and resistance to stress induced by high levels of dissolved O2 increased, beyond axenic performance, as a result of heterotrophic partnership. Coordinated transcriptional responses transcending both species were observed and used to infer specific interactions resulting from the synthesis and exchange of resources. The cyanobacterium responded to heterotrophic partnership by altering expression of core genes involved with photosynthesis, carbon uptake/fixation, vitamin synthesis, and scavenging of reactive oxygen species (ROS). IMPORTANCE This study elucidates how a cyanobacterial primary producer acclimates to heterotrophic partnership by modulating the expression levels of key metabolic genes. Heterotrophic bacteria can indirectly regulate the physiology of the photoautotrophic primary producers, resulting in physiological changes identified here, such as increased intracellular ROS. Some of the interactions inferred from this model system represent putative principles of metabolic coupling in phototrophic-heterotrophic partnerships. PMID:28289730

  8. Prevalence of periodontopathogenic bacteria in patients suffering from periodontitis using culture and PCR methods

    Directory of Open Access Journals (Sweden)

    Amir Aliramezani

    2012-01-01

    Full Text Available Background and Aims: Periodontitis is one of the most common oral diseases with the various incidence rates in different populations. A number of bacteria are considered as the major etiologic agents of periodontitis. The aim of the present study was to determine the prevalence of periodontopathogen bacteria in patients using both PCR and culture techniques.Materials and Methods: In this study, one-hundred patients (including 62 females and 38 males with an average age of 49±11.5 years with adult periodontitis referred to periodontics department of School of Dentistry/Tehran University of Medical Sciences were investigated. The samples were taken and sent immediately to the laboratory for culture and molecular evaluation. The PCR was performed using specific primers and the statistical analysis of data was performed using SPSS statistic software and McNemar test.Results: The results demonstrated that the total detection rate in culture method was 64%. The rate of Aggregatibacter actinomycetemcomitans (Aa was 28% which was significantly higher than that of Porphyromonas gingivalis (Pg (6% and Prevotella intermedia (Pi (3%. 27% of cases showed mixed bacterial growth. 65% of patients were positive using molecular method. The rate of Aa (30% was significantly higher than that of Pg (7% and Pi (5%. The mixed PCR positive rate containing of Aa, Pg and Pi was (23%.Conclusion: In this study, it was found that most of the bacteria isolated using culture and molecular methods were Aa, Pg and Pi, respectively. Although the detection frequencies of both techniques were similar, the specificity, sensitivity and bacterial detection speed of the PCR technique is obviously higher. Therefore, the use of molecular techniques is strongly recommended. However, both techniques seem to be suitable for microbiological diagnostics.

  9. Heterotrophic free-living and particle-bound bacterial cell size in the river Cauvery and its downstream tributaries

    Indian Academy of Sciences (India)

    T S Harsha; Sadanand M Yamakanamardi; M Mahadevaswamy

    2007-03-01

    This is the first comprehensive study on planktonic heterotrophic bacterial cell size in the river Cauvery and its important tributaries in Karnataka State, India. The initial hypothesis that the mean cell size of planktonic heterotrophic bacteria in the four tributaries are markedly different from each other and also from that in the main river Cauvery was rejected, because all five watercourses showed similar planktonic heterotrophic bacterial cell size. Examination of the correlation between mean heterotrophic bacterial cell size and environmental variables showed four correlations in the river Arkavathy and two in the river Shimsha. Regression analysis revealed that 18% of the variation in mean heterotrophic free-living bacterial cell size was due to biological oxygen demand (BOD) in the river Arkavathy, 11% due to surface water velocity (SWV) in the river Cauvery and 11% due to temperature in the river Kapila. Heterotrophic particle-bound bacterial cell size variation was 28% due to chloride and BOD in the river Arkavathy, 11% due to conductivity in the river Kapila and 8% due to calcium in the river Cauvery. This type of relationship between heterotrophic bacterial cell size and environmental variables suggests that, though the mean heterotrophic bacterial cell size was similar in all the five water courses, different sets of environmental variables apparently control the heterotrophic bacterial cell size in the various water bodies studied in this investigation. The possible cause for this environmental (bottom–up) control is discussed.

  10. Carbon dynamics in highly heterotrophic subarctic thaw ponds

    Directory of Open Access Journals (Sweden)

    T. Roiha

    2015-07-01

    Full Text Available Global warming has accelerated the formation of permafrost thaw ponds in several subarctic and arctic regions. These ponds are net heterotrophic as evidenced by their greenhouse gas (GHG supersaturation levels (CO2 and CH4, and generally receive large terrestrial carbon inputs from the thawing and eroding permafrost. We measured seasonal and vertical variations in the concentration and type of dissolved organic matter (DOM in five subarctic thaw (thermokarst ponds in northern Quebec, and explored how environmental gradients influenced heterotrophic and phototrophic biomass and productivity. Late winter DOM had low aromaticity indicating reduced inputs of terrestrial carbon, while the high concentration of dissolved organic carbon (DOC suggests that some production of non-chromophoric dissolved compounds by the microbial food web took place under the ice cover. Summer DOM had a strong terrestrial signature, but was also characterized with significant inputs of algal-derived carbon, especially at the pond surface. During late winter, bacterial production was low (maximum of 0.8 mg C m−3 d−1 and was largely based on free-living bacterioplankton (58 %. Bacterial production in summer was high (up to 58 mg C m−3 d−1, dominated by particle-attached bacteria (67 %, and strongly correlated to the amount of terrestrial carbon. Primary production was restricted to summer surface waters due to strong light limitation deeper in the water column or in winter. The phototrophic biomass was equal to the heterotrophic biomass, but as the algae were mostly composed of mixotrophic species, most probably they used bacteria rather than solar energy in such shaded ponds. According to the δ13C analyses, non-algal carbon supported 51 % of winter and 37 % of summer biomass of the phantom midge larvae, Chaoborus sp., that are at the top of the trophic chain. Our results point to a strong heterotrophic energy pathway in these thaw pond ecosystems, where

  11. Carbon dynamics in highly heterotrophic subarctic thaw ponds

    Science.gov (United States)

    Roiha, T.; Laurion, I.; Rautio, M.

    2015-12-01

    Global warming has accelerated the formation of permafrost thaw ponds in several subarctic and arctic regions. These ponds are net heterotrophic as evidenced by their greenhouse gas (GHG) supersaturation levels (CO2 and CH4), and generally receive large terrestrial carbon inputs from the thawing and eroding permafrost. We measured seasonal and vertical variations in the concentration and type of dissolved organic matter (DOM) in five subarctic thaw (thermokarst) ponds in northern Quebec, and explored how environmental gradients influenced heterotrophic and phototrophic biomass and productivity. Late winter DOM had low aromaticity indicating reduced inputs of terrestrial carbon, while the high concentration of dissolved organic carbon (DOC) suggests that some production of non-chromophoric dissolved compounds by the microbial food web took place under the ice cover. Summer DOM had a strong terrestrial signature, but was also characterized with significant inputs of algal-derived carbon, especially at the pond surface. During late winter, bacterial production was low (maximum of 0.8 mg C m-3 d-1) and was largely based on free-living bacterioplankton (58 %). Bacterial production in summer was high (up to 58 mg C m-3 d-1), dominated by particle-attached bacteria (67 %), and strongly correlated with the amount of terrestrial carbon. Primary production was restricted to summer surface waters due to strong light limitation deeper in the water column or in winter. The phototrophic biomass was equal to the heterotrophic biomass, but as the algae were mostly composed of mixotrophic species, most probably they used bacteria rather than solar energy in such shaded ponds. Our results point to a strong heterotrophic energy pathway in these thaw pond ecosystems, where bacterioplankton dominates the production of new carbon biomass in both summer and winter.

  12. Comparing rapid and culture indicator bacteria methods at inland lake beaches

    Science.gov (United States)

    Francy, Donna S.; Bushon, Rebecca N.; Brady, Amie M.G.; Kephart, Christopher M.

    2013-01-01

    A rapid method, quantitative polymerase chain reaction (qPCR), for quantifying indicator bacteria in recreational waters is desirable for public health protection. We report that replacing current Escherichia coli standards with new US Environmental Protection Agency beach action values (BAVs) for enterococci by culture or qPCR may result in more advisories being posted at inland recreational lakes. In this study, concentrations of E. coli and enterococci by culture methods were compared to concentrations of Enterococcus spp. by qPCR at 3 inland lake beaches in Ohio. The E. coli and enterococci culture results were significantly related at all beaches; however, the relations between culture results and Enterococcus spp. qPCR results were not always significant and differed among beaches. All the qPCR results exceeded the new BAV for Enterococcus spp. by qPCR, whereas only 23.7% of culture results for E. coli and 79% of culture results for enterococci exceeded the current standard for E. coli or BAV for enterococci.

  13. [Endogenous respiration process analysis of heterotrophic biomass and autotrophic biomass based on respiration map ].

    Science.gov (United States)

    Li, Zhi-hua; Bai, Xu-li; Zhang, Qin; Liu, Yi; He, Chun-bo

    2014-09-01

    The endogenous process is an important metabolic part of the activated sludge, and the understanding of this process is still unclear. Characteristics of endogenous respiration for heterotrophic bacteria and autotrophic nitrifiers were analyzed using respirogram. Results showed that both heterotrophic and autotrophic bacteria entered the stage of endogenous respiration at almost the same time, but heterotrophic bacteria first entered the stage of dormancy i. e. , they were easier to recover a higher proportion of biomass during the dormancy stage, indicating that heterotrophic bacteria exhibited strong environmental adaptability. Autotrophic bacteria were, however, quite different. This finding confirmed that autotrophic bacteria were more vulnerable from the viewpoint of endogenous respiration. In addition, the study also found that the increase of endogenous respiration rate ratio reflected the decreased sludge activity. And the proportion of endogenous respiration was an important parameter to characterize the activity of activated sludge, which can be used as a quantitative index for the health status of activated sludge. The findings further deepened the understanding of endogenous respiration process and provided a theoretical basis for the operation and management of wastewater treatment plants.

  14. 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.

  15. Evaluation on the microbial interactions of anaerobic ammonium oxidizers and heterotrophs in Anammox biofilm

    DEFF Research Database (Denmark)

    Ni, Bing-Jie; Ruscalleda, Mael; Smets, Barth F.

    2012-01-01

    Anaerobic ammonium oxidation (Anammox) is a cost-effective new process to treat high-strength nitrogenous wastewater. In this work, the microbial interactions of anaerobic ammonium oxidizers and heterotrophs through the exchange of soluble microbial products (SMP) in Anammox biofilm....... Experimental results showed the heterotrophs could grow both on SMP and decay released substrate from the metabolism of the Anammox bacteria. However, heterotrophic growth in Anammox biofilm (23%) was significantly lower than that of nitrifying biofilm (30–50%). The model predictions matched well...... with the experimental observations of the bacterial distribution, as well as the nitrogenous transformations in batch and continuous experiments. The modeling results showed that low nitrogen surface loading resulted in a lower availability of SMP leading to low heterotrophic growth in Anammox biofilm, but high...

  16. Electromechanical and elastic probing of bacteria in a cell culture medium.

    Science.gov (United States)

    Thompson, G L; Reukov, V V; Nikiforov, M P; Jesse, S; Kalinin, S V; Vertegel, A A

    2012-06-22

    Rapid phenotype characterization and identification of cultured cells, which is needed for progress in tissue engineering and drug testing, requires an experimental technique that measures physical properties of cells with sub-micron resolution. Recently, band excitation piezoresponse force microscopy (BEPFM) has been proven useful for recognition and imaging of bacteria of different types in pure water. Here, the BEPFM method is performed for the first time on physiologically relevant electrolyte media, such as Dulbecco's phosphate-buffered saline (DPBS) and Dulbecco's modified Eagle's medium (DMEM). Distinct electromechanical responses for Micrococcus lysodeikticus (Gram-positive) and Pseudomonas fluorescens (Gram-negative) bacteria in DPBS are demonstrated. The results suggest that mechanical properties of the outer surface coating each bacterium, as well as the electrical double layer around them, are responsible for the BEPFM image formation mechanism in electrolyte media.

  17. Draft Genome Sequence of Limnobacter sp. Strain CACIAM 66H1, a Heterotrophic Bacterium Associated with Cyanobacteria.

    Science.gov (United States)

    da Silva, Fábio Daniel Florêncio; Lima, Alex Ranieri Jerônimo; Moraes, Pablo Henrique Gonçalves; Siqueira, Andrei Santos; Dall'Agnol, Leonardo Teixeira; Baraúna, Anna Rafaella Ferreira; Martins, Luisa Carício; Oliveira, Karol Guimarães; de Lima, Clayton Pereira Silva; Nunes, Márcio Roberto Teixeira; Vianez-Júnior, João Lídio Silva Gonçalves; Gonçalves, Evonnildo Costa

    2016-05-19

    Ecological interactions between cyanobacteria and heterotrophic prokaryotes are poorly known. To improve the genomic studies of heterotrophic bacterium-cyanobacterium associations, the draft genome sequence (3.2 Mbp) of Limnobacter sp. strain CACIAM 66H1, found in a nonaxenic culture of Synechococcus sp. (cyanobacteria), is presented here.

  18. Portable self-contained cultures for phage and bacteria made of paper and tape.

    Science.gov (United States)

    Funes-Huacca, Maribel; Wu, Alyson; Szepesvari, Eszter; Rajendran, Pavithra; Kwan-Wong, Nicholas; Razgulin, Andrew; Shen, Yi; Kagira, John; Campbell, Robert; Derda, Ratmir

    2012-11-01

    In this paper, we demonstrate that a functional, portable device for the growth of bacteria or amplification of bacteriophage can be created using simple materials. These devices are comprised of packing tape, sheets of paper patterned by hydrophobic printer ink, and a polydimethyl siloxane (PDMS) membrane, which is selectively permeable to oxygen but non-permeable to water. These devices supply bacteria with oxygen and prevent the evaporation of media for a period over 48 h. The division time of E. coli and the amplification of the phage M13 in this device are similar to the rates measured on agar plates and in shaking cultures. The growth of bacteria with a fluorescent mCherry reporter can be quantified using a flatbed scanner or a cell phone camera. Permeating devices with commercial viability dye (PrestoBlue) can be used to detect low copy number of E. coli (1-10 CFU in 100 μL) and visualize microorganisms in environmental samples. The platform, equipped with bacteria that carry inducible mCherry reporter could also be used to quantify the concentration of the inducer (here, arabinose). Identical culture platforms can, potentially, be used to quantify the induction of gene expression by an engineered phage or by synthetic transcriptional regulators that respond to clinically relevant molecules. The majority of measurement and fabrication procedures presented in this report have been replicated by low-skilled personnel (high-school students) in a low-resource environment (high-school classroom). The fabrication and performance of the device have also been tested in a low-resource laboratory setting by researchers in Nairobi, Kenya. Accordingly, this platform can be used as both an educational tool and as a diagnostic tool in low-resource environments worldwide.

  19. Characterization of microalgae-bacteria consortium cultured in landfill leachate for carbon fixation and lipid production.

    Science.gov (United States)

    Zhao, Xin; Zhou, Yan; Huang, Sheng; Qiu, Duanyang; Schideman, Lance; Chai, Xiaoli; Zhao, Youcai

    2014-03-01

    The characteristics of cultivating high-density microalgae-bacteria consortium with landfill leachate was tested in this study. Landfill leachate was collected from Laogang landfill operated for over 10 years in Shanghai, China. The maximum biomass concentration of 1.58g L(-1) and chlorophyll a level of 22mg L(-1) were obtained in 10% leachate spike ratio. Meanwhile, up to 90% of the total nitrogen in landfill leachate was removed in culture with 10% leachate spike ratio with a total nitrogen concentration of 221.6mg L(-1). The fluorescence peak of humic-like organic matters red shifted to longer wavelengths by the end of culture, indicating that microalgae-bacteria consortium was effective for treating landfill leachate contaminants. Furthermore, with the leachate spike ratio of 10%, the maximum lipid productivity and carbon fixation were 24.1 and 65.8mg L(-1)d(-1), respectively. Results of this research provide valuable information for optimizing microalgae culture in landfill leachate.

  20. An initial investigation into the ecology of culturable aerobic postmortem bacteria.

    Science.gov (United States)

    Chun, Lauren P; Miguel, Marcus J; Junkins, Emily N; Forbes, Shari L; Carter, David O

    2015-12-01

    Postmortem microorganisms are increasingly recognized for their potential to serve as physical evidence. Yet, we still understand little about the ecology of postmortem microbes, particularly those associated with the skin and larval masses. We conducted an experiment to characterize microbiological and chemical properties of decomposing swine (Sus scrofa domesticus) carcasses on the island of Oahu, Hawaii, USA, during June 2013. Bacteria were collected from the head, limb, and larval mass during the initial 145h of decomposition. We also measured the pH, temperature, and oxidation-reduction potential of larval masses in situ. Bacteria were cultured aerobically on Standard Nutrient Agar at 22°C and identified using protein or genetic signals. Carcass decomposition followed a typical sigmoidal pattern and associated bacterial communities differed by sampling location and time since death, although all communities were dominated by phyla Actinobacteria, Firmicutes, and Proteobacteria. Larval masses were reducing environments (~-200mV) of neutral pH (6.5-7.5) and high temperature (35°C-40°C). We recommend that culturable postmortem and larval mass microbiology and chemistry be investigated in more detail, as it has potential to complement culture-independent studies and serve as a rapid estimate of PMI.

  1. Co-culturing Effects of Coexisting Bacteria on Wood Degradation by Trametes versicolor.

    Science.gov (United States)

    Kamei, Ichiro

    2017-01-01

    White-rot fungi are the main decomposers of wood cell-wall polymer in forest ecosystems. Little is known, however, about the interactions between white-rot fungi and other coexisting microorganisms in decayed wood. A white-rot fungus, Trametes versicolor strain TN6F, was isolated from a fruit body, and 44 strains of coexisting cultivable bacteria were isolated from its substrate, natural white rot-decayed wood. The effects of these bacteria on fungal growth were examined by an in vitro confrontation growth assay. Among the isolates, nine bacterial strains inhibited the growth of strain TN6F, while 35 strains did not affect the growth of TN6F. However, when co-cultured with strain TN6F on wood powder, many bacterial strains promoted the weight loss of the substrate. A subsequent chemical composition analysis showed that co-culturing accelerated delignification. Higher laccase activity was detected when strain TN6F was co-cultured on wood powder medium with bacterial strains TN6W-26 or TN6W-27. These results indicate that some bacterial strains might promote wood degradation.

  2. Acoustic trapping for bacteria identification in positive blood cultures with MALDI-TOF MS.

    Science.gov (United States)

    Hammarström, Björn; Nilson, Bo; Laurell, Thomas; Nilsson, Johan; Ekström, Simon

    2014-11-04

    Matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is currently changing the clinical routine for identification of microbial pathogens. One important application is the rapid identification of bacteria for the diagnosis of bloodstream infections (BSI). A novel approach based on acoustic trapping and an integrated selective enrichment target (ISET) microchip that improves the sample preparation step for this type of analysis is presented. The method is evaluated on clinically relevant samples in the form of Escherichia coli infected blood cultures. It is shown that noncontact acoustic trapping enables capture, enrichment, and washing of bacteria directly from the complex background of crude blood cultures. The technology replaces centrifugation-based separation with a faster and highly automated sample preparation method that minimizes manual handling of hazardous pathogens. The presented method includes a solid phase extraction step that was optimized for enrichment of the bacterial proteins and peptides that are used for bacterial identification. The acoustic trapping-based assay provided correct identification in 12 out 12 cases of E. coli positive blood cultures with an average score of 2.19 ± 0.09 compared to 1.98 ± 0.08 when using the standard assay. This new technology opens up the possibility to automate and speed up an important and widely used diagnostic assay for bloodstream infections.

  3. Physico-chemical properties of polyhydroxyalkanoate produced by mixed-culture nitrogen-fixing bacteria.

    Science.gov (United States)

    Patel, Meeta; Gapes, Daniel J; Newman, Roger H; Dare, Peter H

    2009-03-01

    Ultra-high molecular weight polyhydroxyalkanoates (PHAs) with low polydispersity index (PDI = 1.3) were produced in a novel, pilot scale application of mixed cultures of nitrogen-fixing bacteria. The number average molecular weight (M (n)) of the poly(3-hydroxybutyrate) (P(3HB)) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(3HB-co-3HV)) was determined to be 2.4 x 10(6) and 2.5 x 10(6) g mol(-1), respectively. Using two types of carbon sources, biomass contents of the P(3HB) and P(3HB-co-3HV) were 18% and 30% (PHA in dry biomass), respectively. The extracted polymers were analysed for their physical properties using analytical techniques such as nuclear magnetic resonance (NMR) spectroscopy, differential scanning calorimetry (DSC) and gel permeation chromatography (GPC). NMR confirmed the formation of homopolymer and copolymer. DSC showed a single melting endotherm peak for both polymers, with enthalpies that indicated crystallinity indices of 44% and 37% for P(3HB) and P(3HB-co-3HV), respectively. GPC showed a sharp unimodal trace for both polymers, reflecting the homogeneity of the polymer chains. The work described here emphasises the potential of mixed colony nitrogen-fixing bacteria cultures for producing biodegradable polymers which have properties that are very similar to those from their pure-culture counterparts and therefore making a more economically viable route for obtaining biopolyesters.

  4. IDENTIFICATION OF BACTERIA IN BLOOD CULTURES FROM CLINICALLY ILL CAPTIVE ANTILLEAN MANATEES (TRICHECHUS MANATUS MANATUS).

    Science.gov (United States)

    Silva, Mariana C O; Attademo, Fernanda F L; Freire, Augusto C B; Sousa, Glaucia P; Luna, Fábia O; Lima, Débora C V; Mota, Rinaldo A; Mendes, Emiko S; Silva, Jean C R

    2017-03-01

    Between September 2001 and March 2013, 62 bacterial cultures (37 aerobic and 25 anaerobic) were performed on 37 blood samples from 23 Antillean manatees ( Trichechus manatus manatus) that were kept in captivity at the Brazilian National Center for Research and Conservation of Aquatic Mammals (CMA) in Pernambuco (CMA-PE) and Alagoas (CMA-AL), Brazil. All of the animals sampled exhibited clinical signs at the time of sampling including abscesses (n = 8), debilitation and anorexia (n = 22), and profound lethargy-moribundity (n = 7). The 4 animals with profound lethargy-moribundity died shortly after sampling of unknown causes. Bacteria were isolated from 15/37 (40.5%) and aerobic blood cultures from 13/23 animals (56.5%). None of the anaerobic cultures were positive. Aeromonas caviae , Aeromonas hydrophila , Aeromonas sp., Escherichia coli , Leclercia adecarboxylata , Pantoea agglomerans , Pseudomonas aeruginosa , Pseudomonas stutzeri , Pseudomonas sp., Sphingomonas paucimobilis , coagulase-negative Staphylococcus, and Staphylococcus epidermidis were each found in only one animal; Staphylococcus spp. was found in two; and Vibrio fluvialis in four. Thirteen samples had only one bacteria isolated, one sample had two bacteria, and one sample had three bacteria isolated. Regarding sex, age group, and origin among the manatees examined, 54.5% (6/11) of the females, 58.3% (7/12) of the males, 40% (2/5) of the calves, 66.7% (8/12) of the juveniles, 50% (3/6) of the adults, 55.5% (10/18) at CMA-PE, and 60% (3/5) at CMA-AL were found to be positive for bacterial growth during at least one sampling time. All Antillean manatees were clinically ill. Regarding clinical signs, bacteria were found in 50% (11/22) of blood samples of the animals showing debilitation and anorexia, 1 of 8 (12.5%) of blood samples of the animals showing abscesses, and 3 of 7 (42.9%) of blood samples of the animals showing profound lethargy-moribundity.

  5. Variation of culturable bacteria along depth in the East Rongbuk ice core, Mt. Everest

    Directory of Open Access Journals (Sweden)

    Liang Shen

    2012-05-01

    Full Text Available Ice melt water from a 22.27 m ice core which was drilled from the East Rongbuk Glacier, Mt. Everest was incubation in two incubation ways: plate melt water directly and enrichment melt water prior plate, respectively. The abundance of cultivable bacteria ranged from 0–295 CFU mL−1 to 0–1720 CFU mL−1 in two incubations with a total of 1385 isolates obtained. Comparing to direct cultivation, enrichment cultivation recovered more bacteria. Pigment-producing bacteria accounted for an average of 84.9% of total isolates. Such high percentage suggested that pigment production may be an adaptive physiological feature for the bacteria in ice core to cope with strong ultraviolet radiation on the glacier. The abundances of cultivable bacteria and pigment-producing isolates varied synchronously along depth: higher abundance in the middle and lower at the top and bottom. It indicated that the middle part of the ice core was hospitable for the microbial survival. Based on the physiological properties of the colonies, eighty-nine isolates were selected for phylogenetic analysis. Obtained 16S rRNA gene sequences fell into four groups: Firmicutes, Alpha-Proteobacteria, Gamma-Proteobacteria, and Actinobacteria, with the Firmicutes being dominant. Microbial compositions derived from direct and enrichment cultivations were not overlapped. We suggest that it is a better way to explore the culturable microbial diversity in ice core by combining the approaches of both direct and enrichment cultivation.

  6. Identification of bacteria associated with feline chronic gingivostomatitis using culture-dependent and culture-independent methods.

    Science.gov (United States)

    Dolieslager, Sanne M J; Riggio, Marcello P; Lennon, Alan; Lappin, David F; Johnston, Norman; Taylor, David; Bennett, David

    2011-02-24

    Feline chronic gingivostomatitis (FCGS) is a chronic inflammatory disease of the oral cavity that causes severe pain and distress. There are currently no specific treatment methods available and little is known regarding its aetiology, although bacteria are thought to play a major role. The purpose of this study was to identify the oral bacterial flora in normal and diseased cats. Oral swabs were obtained from the palatoglossal folds of eight cats (three normal and five FCGS) and were subjected to microbiological culture. Pasteurella pneumotropica and Pasteurella multocida subsp. multocida were the most prevalent species identified by culture methods in the normal and FCGS samples, respectively. Bacteria were also identified using culture-independent methods (bacterial 16S rRNA gene sequencing). For the normal samples, 158 clones were analysed and 85 clones were sequenced. Capnocytophaga canimorsus (10.8% of clones analysed) was the predominant species. Uncultured species accounted for 8.2% of clones analysed, and 43.7% of clones analysed represented potentially novel species. For the FCGS samples, 253 clones were analysed and 91 clones were sequenced. The predominant species was P. multocida subsp. multocida (51.8% of clones analysed). Uncultured species accounted for 8.7% of clones analysed, and 4.7% of clones analysed represented potentially novel species. It is concluded that the oral flora in cats with FCGS appears to be less diverse than that found in normal cats. However, P. multocida subsp. multocida is found to be significantly more prevalent in FCGS than in normal cats and consequently may be of aetiological significance in this disease. Copyright © 2010 Elsevier B.V. All rights reserved.

  7. Diversity of culturable halophilic sulfur-oxidizing bacteria in hypersaline habitats.

    Science.gov (United States)

    Sorokin, Dimitry Yu; Tourova, Tatjana P; Lysenko, Anatoly M; Muyzer, Gerard

    2006-10-01

    Unexpectedly high culturable diversity of moderately and extremely halophilic obligately chemolithoautotrophic sulfur-oxidizing bacteria (SOB) was discovered in the sediments of various hypersaline habitats, including chloride-sulfate lakes in Mongolia, Russia and Ukraine, a sea saltern in Slovenia and a deep-sea salt brine from the Mediterranean. Six different groups of halophilic SOB, including four new genera, all belonging to the Gammaproteobacteria, were found. Two groups of moderately halophilic strictly aerobic SOB dominated at 2 M NaCl, including representatives of the genus Halothiobacillus (in fully aerobic conditions) and Thiomicrospira (in micro-oxic conditions). Under denitrifying conditions at 2 M NaCl, a group of moderately halophilic and facultatively anaerobic SOB was selected, capable of complete denitrification of nitrate. The group represents a new genus with closest relatives among as yet undescribed marine thiodenitrifying isolates. With thiocyanate as a substrate, an enrichment culture at 2 M NaCl yielded a pure culture of moderately halophilic SOB capable of aerobic growth with thiocyanate and thiosulfate at up to 4 M NaCl. Furthermore, this bacterium also grew anaerobically using nitrite as electron acceptor. It formed a new lineage distantly related to the genus Thiomicrospira. Enrichments at 4 M NaCl resulted in the domination of two different, previously unknown, groups of extremely halophilic SOB. Under oxic conditions, they were represented by strictly aerobic spiral-shaped bacteria, related to the Ectothiorhodospiraceae, while under denitrifying conditions a group of facultatively anaerobic nitrate-reducing bacteria with long rod-shaped cells was selected, distantly related to the genus Acidithiobacillus.

  8. Analysis of adult otitis media: polymerase chain reaction versus culture for bacteria and viruses.

    Science.gov (United States)

    Liederman, E M; Post, J C; Aul, J J; Sirko, D A; White, G J; Buchman, C A; Ehrlich, G D

    1998-01-01

    Recent studies using the polymerase chain reaction (PCR) have identified bacterial and viral genomic sequences in culture-negative pediatric middle ear effusions. To evaluate this technique in adults, 19 effusions were analyzed to compare bacterial and viral culture and PCR detection of Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and adenovirus. Effusions from 4 subjects positive for human immunodeficiency virus (HIV) were analyzed by PCR for HIV virus. Three of 19 effusions were culture-positive for bacteria, and 0 of 19 for viruses. Fifteen of 19 effusions were PCR-positive for bacterial genomic sequences, and 0 of 19 for adenovirus. Thirteen of 15 PCR-positive specimens demonstrated S pneumoniae, 5 of 15 H influenzae, and 0 of 13 M catarrhalis. All 4 effusions from HIV-positive subjects were PCR-positive for HIV. No effusion was culture-positive and PCR-negative. These results confirm that culture-negative middle ear effusions contain genomic sequences from bacterial pathogens. Finding of HIV RNA and DNA in effusion from HIV-positives suggests replicating virus in this fluid.

  9. Evaluation of mono or mixed cultures of lactic acid bacteria in type II sourdough system.

    Science.gov (United States)

    Ekinci, Raci; Şimşek, Ömer; Küçükçuban, Ayca; Nas, Sebahattin

    2016-01-01

    The aim of this study was to evaluate the use of mono and mixed lactic acid bacteria (LAB) cultures to determine suitable LAB combinations for a type II sourdough system. In this context, previously isolated sourdough LAB strains with antimicrobial activity, which included Lactobacillus plantarum PFC22, Lactobacillus brevis PFC31, Pediococcus acidilactici PFC38, and Lactobacillus sanfranciscensis PFC80, were used as mono or mixed culture combinations in a fermentation system to produce type II sourdough, and subsequently in bread dough production. Compared to the monoculture fermentation of dough, the use of mixed cultures shortened the adaptation period by half. In addition, the use of mixed cultures ensured higher microbial viability, and enhanced the fruity flavor during bread dough production. It was determined that the combination of L. plantarum PFC22 + P. acidilactici PFC38 + L. sanfranciscensis PFC80 is a promising culture mixture that can be used in the production of type II sourdough systems, and that may also contribute to an increase in metabolic activity during bread production process.

  10. Continous application of bioorganic fertilizer induced resilient culturable bacteria community associated with banana Fusarium wilt suppression

    Science.gov (United States)

    Fu, Lin; Ruan, Yunze; Tao, Chengyuan; Li, Rong; Shen, Qirong

    2016-06-01

    Fusarium wilt of banana always drives farmers to find new land for banana cultivation due to the comeback of the disease after a few cropping years. A novel idea for solving this problem is the continuous application of bioorganic fertilizer (BIO), which should be practiced from the beginning of banana planting. In this study, BIO was applied in newly reclaimed fields to pre-control banana Fusarium wilt and the culturable rhizobacteria community were evaluated using Biolog Ecoplates and culture-dependent denaturing gradient gel electrophoresis (CD-DGGE). The results showed that BIO application significantly reduced disease incidences and increased crop yields, respectivly. And the stabilized general bacterial metabolic potential, especially for the utilization of carbohydrates, carboxylic acids and phenolic compounds, was induced by BIO application. DGGE profiles demonstrated that resilient community structure of culturable rhizobacteria with higher richness and diversity were observed in BIO treated soils. Morever, enriched culturable bacteria affiliated with Firmicutes, Gammaproteobacteria and Actinobacteria were also detected. In total, continuous application of BIO effectively suppressed Fusarium wilt disease by stabilizing culturable bacterial metabolic potential and community structure. This study revealed a new method to control Fusarium wilt of banana for long term banana cultivation.

  11. Growth rate characteristics of acidophilic heterotrophic organisms from mine waste rock piles

    Science.gov (United States)

    Yacob, T. W.; Silverstein, J.; Jenkins, J.; Andre, B. J.; Rajaram, H.

    2010-12-01

    Autotrophic iron oxidizing bacteria play a key role in pyrite oxidation and generation of acid mine drainage AMD. Scarcity of organic substrates in many disturbed sites insures that IOB have sufficient oxygen and other nutrients for growth. It is proposed that addition of organic carbon substrate to waste rock piles will result in enrichment of heterotrophic microorganisms limiting the role of IOB in AMD generation. Previous researchers have used the acidophilic heterotroph Acidiphilium cryptum as a model to study the effects of organic substrate addition on the pyrite oxidation/AMD cycle. In order to develop a quantitative model of effects such as competition for oxygen, it is necessary to use growth and substrate consumption rate expressions, and one approach is to choose a model strain such as A. cryptum for kinetic studies. However we have found that the growth rate characteristics of A. cryptum may not provide an accurate model of the remediation effects of organic addition to subsurface mined sites. Fluorescent in-situ hybridization (FISH) assays of extracts of mine waste rock enriched with glucose and yeast extract did not produce countable numbers of cells in the Acidiphilium genus, with a detection limit of3 x 104 cells/gram rock, despite evidence of the presence of well established heterotrophic organisms. However, an MPN enrichment produced heterotrophic population estimates of 1x107 and 1x109 cells/gram rock. Growth rate studies of A. cryptum showed that cultures took 120 hours to degrade 50% of an initial glucose concentration of 2,000 mg/L. However a mixed culture enriched from mine waste rock consumed 100% of the same amount of glucose in 24 hours. Substrate consumption data for the mixed culture were fit to a Monod growth model: {dS}/{dt} = μ_{max}S {( {X_0}/{Y} + S_0 -S )}/{(K_s +S)} Kinetic parameters were estimated utilizing a non linear regression method coupled with an ODE solver. The maximum specific growth rate of the mixed population with

  12. Comparison of dry medium culture plates for mesophilic aerobic bacteria in milk, ice cream, ham, and codfish fillet products.

    Science.gov (United States)

    Park, Junghyun; Kim, Myunghee

    2013-12-01

    This study was performed to compare the performance of Sanita-Kun dry medium culture plate with those of traditional culture medium and Petrifilm dry medium culture plate for the enumeration of the mesophilic aerobic bacteria in milk, ice cream, ham, and codfish fillet. Mesophilic aerobic bacteria were comparatively evaluated in milk, ice cream, ham, and codfish fillet using Sanita-Kun aerobic count (SAC), Petrifilm aerobic count (PAC), and traditional plate count agar (PCA) media. According to the results, all methods showed high correlations of 0.989~1.000 and no significant differences were observed for enumerating the mesophilic aerobic bacteria in the tested food products. SAC method was easier to perform and count colonies efficiently as compared to the PCA and PAC methods. Therefore, we concluded that the SAC method offers an acceptable alternative to the PCA and PAC methods for counting the mesophilic aerobic bacteria in milk, ice cream, ham, and codfish fillet products.

  13. Modelling the effect of lactic acid bacteria from starter- and aroma culture on growth of Listeria monocytogenes in cottage cheese

    DEFF Research Database (Denmark)

    Østergaard, Nina Bjerre; Eklöw, Annelie; Dalgaard, Paw

    2014-01-01

    Four mathematical models were developed and validated for simultaneous growth of mesophilic lactic acid bacteria from added cultures and Listeria monocytogenes, during chilled storage of cottage cheese with freshor cultured cream dressing. The mathematical models include the effect of temperature...... cheese to improvemodel performance. The inhibiting effect of mesophilic lactic acid bacteria from added cultures on growth of L. monocytogenes was efficiently modelled using the Jameson approach. The new models appropriately predicted the maximum population density of L. monocytogenes in cottage cheese....... The developed models were successfully validated by using 25 growth rates for L. monocytogenes, 17 growth rates for lactic acid bacteria and a total of 26 growth curves for simultaneous growth of L. monocytogenes and lactic acid bacteria in cottage cheese. These data were used in combination with bias...

  14. Volatile organic compounds generated by cultures of bacteria and viruses associated with respiratory infections.

    Science.gov (United States)

    Abd El Qader, Amir; Lieberman, David; Shemer Avni, Yonat; Svobodin, Natali; Lazarovitch, Tsilia; Sagi, Orli; Zeiri, Yehuda

    2015-12-01

    Respiratory infections (RI) can be viral or bacterial in origin. In either case, the invasion of the pathogen results in production and release of various volatile organic compounds (VOCs). The present study examines the VOCs released from cultures of five viruses (influenza A, influenza B, adenovirus, respiratory syncitial virus and parainfluenza 1 virus), three bacteria (Moraxella catarrhalis, Haemophilus influenzae and Legionella pneumophila) and Mycoplasma pneumoniae isolated colonies. Our results demonstrate the involvement of inflammation-induced VOCs. Two significant VOCs were identified as associated with infectious bacterial activity, heptane and methylcyclohexane. These two VOCs have been linked in previous studies to oxidative stress effects. In order to distinguish between bacterial and viral positive cultures, we performed principal component analysis including peak identity (retention time) and VOC concentration (i.e. area under the peak) revealing 1-hexanol and 1-heptadecene to be good predictors.

  15. Identification and Antimicrobial Resistance of Bacteria Isolated from Probiotic Products Used in Shrimp Culture

    DEFF Research Database (Denmark)

    Noor Uddin, Gazi Md; Larsen, Marianne Halberg; Christensen, Henrik

    2015-01-01

    Probiotics are increasingly used in aquaculture to control diseases and improve feed digestion and pond water quality; however, little is known about the antimicrobial resistance properties of such probiotic bacteria and to what extent they may contribute to the development of bacterial resistance...... in aquaculture ponds. Concerns have been raised that the declared information on probiotic product labels are incorrect and information on bacterial composition are often missing. We therefore evaluated seven probiotics commonly used in Vietnamese shrimp culture for their bacterial species content, phenotypic....... used to identify resistance genes and genetic elements associated with horizontal gene transfer. Thirteen bacterial species declared on the probiotic products could not be identified and 11 non-declared Bacillus spp. were identified. Although our culture-based isolation and identification may have...

  16. Identification and Antimicrobial Resistance of Bacteria Isolated from Probiotic Products Used in Shrimp Culture

    DEFF Research Database (Denmark)

    Noor Uddin, Gazi Md; Larsen, Marianne Halberg; Christensen, Henrik;

    2015-01-01

    Probiotics are increasingly used in aquaculture to control diseases and improve feed digestion and pond water quality; however, little is known about the antimicrobial resistance properties of such probiotic bacteria and to what extent they may contribute to the development of bacterial resistance...... in aquaculture ponds. Concerns have been raised that the declared information on probiotic product labels are incorrect and information on bacterial composition are often missing. We therefore evaluated seven probiotics commonly used in Vietnamese shrimp culture for their bacterial species content, phenotypic....... used to identify resistance genes and genetic elements associated with horizontal gene transfer. Thirteen bacterial species declared on the probiotic products could not be identified and 11 non-declared Bacillus spp. were identified. Although our culture-based isolation and identification may have...

  17. Larvicidal and Growth-Inhibitory Activity of Entomopathogenic Bacteria Culture Fluids Against Aedes aegypti (Diptera: Culicidae).

    Science.gov (United States)

    da Silva, João Luiz Rosa; Undurraga Schwalm, Fernanda; Eugênio Silva, Carlos; da Costa, Marisa; Heermann, Ralf; Santos da Silva, Onilda

    2017-01-06

    Dengue, Chikungunya, and Zika are important vector-borne diseases, and Aedes aegypti L. is their main transmitter. As the disease management is mainly based on mosquito control strategies, the search for alternative and cost-effective approaches is ongoing. The Gram-negative bacteria Xenorhabdus nematophila and Photorhabdus luminescens are symbiotically associated with entomopathogenic nematodes and are highly pathogenic for insect larvae. After we have recently confirmed the toxicity of these bacteria in Ae. aegypti larvae, we here evaluated the toxic activity of culture fluids on the development of this mosquito species. Larval susceptibility was assessed by exposing larvae to different concentrations of P. luminescens or X. nematophila culture fluids to confirm whether secondary metabolites might cause the mosquitos' death. Xenorhabdus nematophila culture fluid was more effective and stable during the mosquito pathogenicity bioassays compared to that of P. luminescens Larval mortality started a few hours after exposure of the insects to the fluids. Furthermore, the residual effect of larvicidal activity of X. nematophila fluid persisted at full efficiency for 4 d. Particularly, larval mortality was still higher than 50% for up to 8 d. Exposure of larvae to a sublethal dose of X. nematophila fluid delayed pupation as well as emergence of adult mosquitoes and caused cumulative larval mortality higher than 90% by day 14. Here, we describe for the first time the use of stable culture fluids and therefore secondary metabolites of P. luminescens and X. nematophila as a promising basis for the use as biopesticide for control of Ae. aegypti in the future.

  18. The impact of bitter taste receptor genetics on culturable bacteria in chronic rhinosinusitis.

    Science.gov (United States)

    Rom, D I; Christensen, J M; Alvarado, R; Sacks, R; Harvey, R J

    2017-03-01

    Extra-oral bitter taste receptors have been associated with innate bacterial defence mechanisms. Genetic variation in T2R38 functionality has been shown to be associated with susceptibility to upper respiratory tract infections and chronic rhinosinusitis (CRS). We sought to independently assess the influence of bitter taste receptor genotype on the presence of culturable bacteria in the sinuses. A cross-sectional analysis of patients with CRS undergoing surgery was performed. Middle meatal nasal swabs were sent for microbiological evaluation at the time of the procedure. Mucosal biopsies were taken and sent for bitter taste receptor genotype analysis. Sequencing of 3 polymorphisms in the TAS2R38 gene was performed to identify genotypes as super-tasters (PAV/PAV), non-tasters (AVI/AVI) or heterozygous expression (PAV/AVI). The presence of culturable organisms and common pathogens were compared with bitter taste receptor genotypes. 25 patients (age 52.4 +/- 18.28 years, 51% female) were assessed. Super-tasters comprised 16% of the group, 24% were non-tasters and 48% had heterozygous expression. A cultured pathogen was grown in 48% of patients; 32% gram-positive, 20% gram-negative, 28% grew Staphylococcus aureus and 12% Pseudomonas aeruginosa. A non-taster genotype was predictive of colonised pathogens. Tissue eosinophilia (more than 10 HPF) was seen in 48%. Even in a small sample of patients with CRS, non-taster T2R38 genotype appears to predict the presence of culturable bacteria colonising the sinus cavity at the time of surgery for their condition. A genetic link to patients more likely to become infected is likely.

  19. Selective enrichment and production of highly urease active bacteria by non-sterile (open) chemostat culture.

    Science.gov (United States)

    Cheng, Liang; Cord-Ruwisch, Ralf

    2013-10-01

    In general, bioprocesses can be subdivided into naturally occurring processes, not requiring sterility (e.g., beer brewing, wine making, lactic acid fermentation, or biogas digestion) and other processes (e.g., the production of enzymes and antibiotics) that typically require a high level of sterility to avoid contaminant microbes overgrowing the production strain. The current paper describes the sustainable, non-sterile production of an industrial enzyme using activated sludge as inoculum. By using selective conditions (high pH, high ammonia concentration, and presence of urea) for the target bacterium, highly active ureolytic bacteria, physiologically resembling Sporosarcina pasteurii were reproducibly enriched and then continuously produced via chemostat operation of the bioreactor. When using a pH of 10 and about 0.2 M urea in a yeast extract-based medium, ureolytic bacteria developed under aerobic chemostat operation at hydraulic retention times of about 10 h with urease levels of about 60 μmol min⁻¹ ml⁻¹ culture. For cost minimization at an industrial scale the costly protein-rich yeast extract medium could be replaced by commercial milk powder or by lysed activated sludge. Glutamate, molasses, or glucose-based media did not result in the enrichment of ureolytic bacteria by the chemostat. The concentration of intracellular urease was sufficiently high such that the produced raw effluent from the reactor could be used directly for biocementation in the field.

  20. Genetic diversity of culturable bacteria in oil-contaminated rhizosphere of Galega orientalis

    Energy Technology Data Exchange (ETDEWEB)

    Jussila, Minna M. [Department of Applied Chemistry and Microbiology, Viikki Biocenter, PO Box 56, FI-00014, University of Helsinki (Finland)]. E-mail: minna.m.jussila@helsinki.fi; Jurgens, German [Department of Applied Chemistry and Microbiology, Viikki Biocenter, PO Box 56, FI-00014, University of Helsinki (Finland); Lindstroem, Kristina [Department of Applied Chemistry and Microbiology, Viikki Biocenter, PO Box 56, FI-00014, University of Helsinki (Finland); Suominen, Leena [Department of Applied Chemistry and Microbiology, Viikki Biocenter, PO Box 56, FI-00014, University of Helsinki (Finland)

    2006-01-15

    A collection of 50 indigenous meta-toluate tolerating bacteria isolated from oil-contaminated rhizosphere of Galega orientalis on selective medium was characterized and identified by classical and molecular methods. 16S rDNA partial sequencing showed the presence of five major lineages of the Bacteria domain. Gram-positive Rhodococcus, Bacillus and Arthrobacter and gram-negative Pseudomonas were the most abundant genera. Only one-fifth of the strains that tolerated m-toluate also degraded m-toluate. The inoculum Pseudomonas putida PaW85 was not found in the rhizosphere samples. The ability to degrade m-toluate by the TOL plasmid was detected only in species of the genus Pseudomonas. However, a few Rhodococcus erythropolis strains were found which were able to degrade m-toluate. A new finding was that Pseudomonas migulae strains and a few P. oryzihabitans strains were able to grow on m-toluate and most likely contained the TOL plasmid. Because strain specific differences in degradation abilities were found for P. oryzihabitans, separation at the strain level was important. For strain specific separation (GTG){sub 5} fingerprinting was the best method. A combination of the single locus ribotyping and the whole genomic fingerprinting techniques with the selective partial sequencing formed a practical molecular toolbox for studying genetic diversity of culturable bacteria in oil-contaminated rhizosphere. - Bacterial diversity during rhizoremediation in oil-contaminated soil is characterized by a combination of molecular methods.

  1. Optimized Composition of Functional Bacteria for Bioremediation of Sediment Environment of Shrimp Culture

    Institute of Scientific and Technical Information of China (English)

    李秋芬; 辛福言; 邹玉霞; 陈民山; 唐启升

    2004-01-01

    After the single-strain abilities of organic-pollutant-degrading bacteria in bioremediation of sediment environment of shrimp culture are determined, the multistrain degrading effect of the compositions of different strains is measured. The results indicate that the multi-strains groups have higher degrading ability than the single-strain groups. Three-strain groups are better than two-strain groups, and fourstrain groups are better than three-strain groups and five-strain groups, the groups composed of strains Lt7222, Lt7511, Fc6308 and Gy7018 has the best degrading effect, the CODMn removal rate is 73.2 % in 66 h, and gets to 82.7 % in 114 h, 30 % higher than that of the best single-strain group; Groups of Lt7222, Lt7511, Lt7451 and Gy7018 are the second, whose CODMn removal rate is 82.1% in 114 h, It is suggested that multi-species bacteria be used as functional bacteria in biorernediation ofmariculture environment.

  2. The culturable soil antibiotic resistome: a community of multi-drug resistant bacteria.

    Directory of Open Access Journals (Sweden)

    Fiona Walsh

    Full Text Available Understanding the soil bacterial resistome is essential to understanding the evolution and development of antibiotic resistance, and its spread between species and biomes. We have identified and characterized multi-drug resistance (MDR mechanisms in the culturable soil antibiotic resistome and linked the resistance profiles to bacterial species. We isolated 412 antibiotic resistant bacteria from agricultural, urban and pristine soils. All isolates were multi-drug resistant, of which greater than 80% were resistant to 16-23 antibiotics, comprising almost all classes of antibiotic. The mobile resistance genes investigated, (ESBL, bla NDM-1, and plasmid mediated quinolone resistance (PMQR resistance genes were not responsible for the respective resistance phenotypes nor were they present in the extracted soil DNA. Efflux was demonstrated to play an important role in MDR and many resistance phenotypes. Clinically relevant Burkholderia species are intrinsically resistant to ciprofloxacin but the soil Burkholderia species were not intrinsically resistant to ciprofloxacin. Using a phenotypic enzyme assay we identified the antibiotic specific inactivation of trimethoprim in 21 bacteria from different soils. The results of this study identified the importance of the efflux mechanism in the soil resistome and variations between the intrinsic resistance profiles of clinical and soil bacteria of the same family.

  3. Reducing time to identification of aerobic bacteria and fastidious micro-organisms in positive blood cultures.

    Science.gov (United States)

    Intra, J; Sala, M R; Falbo, R; Cappellini, F; Brambilla, P

    2016-12-01

    Rapid and early identification of micro-organisms in blood has a key role in the diagnosis of a febrile patient, in particular, in guiding the clinician to define the correct antibiotic therapy. This study presents a simple and very fast method with high performances for identifying bacteria by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) after only 4 h of incubation. We used early bacterial growth on PolyViteX chocolate agar plates inoculated with five drops of blood-broth medium deposited in the same point and spread with a sterile loop, followed by a direct transfer procedure on MALDI-TOF MS target slides without additional modification. Ninety-nine percentage of aerobic bacteria were correctly identified from 600 monomicrobial-positive blood cultures. This procedure allowed obtaining the correct identification of fastidious pathogens, such as Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae that need complex nutritional and environmental requirements in order to grow. Compared to the traditional pathogen identification from blood cultures that takes over 24 h, the reliability of results, rapid performance and suitability of this protocol allowed a more rapid administration of optimal antimicrobial treatment in the patients.

  4. Caciotta della Garfagnana cheese: selection and evaluation of autochthonous mesophilic lactic acid bacteria as starter cultures

    Directory of Open Access Journals (Sweden)

    Domenico Cerri

    2011-04-01

    Full Text Available The aim of this study was to isolate, identify and select, with respect to acidification and proteolytic activities, the autochthonous mesophilic lactic acid bacteria (LAB present in milk and Caciotta della Garfagnana, a cheese produced either with raw or thermised cow’s milk in small dairies and family plants of Garfagnana (Tuscany, to obtain LAB strains with attributes suitable to be employed as starter cultures in this type of cheese, particularly when thermised milk is used to control spoilage microflora. Samples of raw milk, curd and cheese were collected from three representative farmers of the production area and used to isolate autochthonous LAB. Phenotypic and genotypic (species-specific PCR assay identification of isolated LAB was done. Twenty-eight strains of LAB isolated from milk, curd and cheese were screened for acidifying and proteolytic activities. LAB strains with the better attributes were used as mesophilic starter cultures in technological trials: experimental cheeses manufactured with the addition of autochthonous LAB and control cheeses were compared for LAB and pH evolution. Experimental cheeses presented a significant increase in the mesophilic lactic acid microflora up to 14 days of ripening and significantly lower pH values up to seven days of ripening. The use of wild selected mesophilic lactic acid bacteria, together with thermisation of milk, for the Caciotta della Garfagnana looks very promising and could help to both standardise the production and improve quality and traditional characteristics of this type of cheese.

  5. Caciotta della Garfagnana cheese: selection and evaluation of autochthonous mesophilic lactic acid bacteria as starter cultures

    Directory of Open Access Journals (Sweden)

    Barbara Turchi

    2011-05-01

    Full Text Available he aim of this study was to isolate, identify and select, with respect to acidification and proteolytic activities, the autochthonous mesophilic lactic acid bacteria (LAB present in milk and Caciotta della Garfagnana, a cheese produced either with raw or thermised cow’s milk in small dairies and family plants of Garfagnana (Tuscany, to obtain LAB strains with attributes suitable to be employed as starter cultures in this type of cheese, particularly when thermised milk is used to control spoilage microflora. Samples of raw milk, curd and cheese were collected from three representative farmers of the production area and used to isolate autochthonous LAB. Phenotypic and genotypic (species-specific PCR assay identification of isolated LAB was done. Twenty-eight strains of LAB isolated from milk, curd and cheese were screened for acidifying and proteolytic activities. LAB strains with the better attributes were used as mesophilic starter cultures in technological trials: experimental cheeses manufactured with the addition of autochthonous LAB and control cheeses were compared for LAB and pH evolution. Experimental cheeses presented a significant increase in the mesophilic lactic acid microflora up to 14 days of ripening and significantly lower pH values up to seven days of ripening. The use of wild selected mesophilic lactic acid bacteria, together with thermisation of milk, for the Caciotta della Garfagnana looks very promising and could help to both standardise the production and improve quality and traditional characteristics of this type of cheese.

  6. Commensal bacteria modulate innate immune responses of vaginal epithelial cell multilayer cultures.

    Science.gov (United States)

    Rose, William A; McGowin, Chris L; Spagnuolo, Rae Ann; Eaves-Pyles, Tonyia D; Popov, Vsevolod L; Pyles, Richard B

    2012-01-01

    The human vaginal microbiome plays a critical but poorly defined role in reproductive health. Vaginal microbiome alterations are associated with increased susceptibility to sexually-transmitted infections (STI) possibly due to related changes in innate defense responses from epithelial cells. Study of the impact of commensal bacteria on the vaginal mucosal surface has been hindered by current vaginal epithelial cell (VEC) culture systems that lack an appropriate interface between the apical surface of stratified squamous epithelium and the air-filled vaginal lumen. Therefore we developed a reproducible multilayer VEC culture system with an apical (luminal) air-interface that supported colonization with selected commensal bacteria. Multilayer VEC developed tight-junctions and other hallmarks of the vaginal mucosa including predictable proinflammatory cytokine secretion following TLR stimulation. Colonization of multilayers by common vaginal commensals including Lactobacillus crispatus, L. jensenii, and L. rhamnosus led to intimate associations with the VEC exclusively on the apical surface. Vaginal commensals did not trigger cytokine secretion but Staphylococcus epidermidis, a skin commensal, was inflammatory. Lactobacilli reduced cytokine secretion in an isolate-specific fashion following TLR stimulation. This tempering of inflammation offers a potential explanation for increased susceptibility to STI in the absence of common commensals and has implications for testing of potential STI preventatives.

  7. Commensal Bacteria Modulate Innate Immune Responses of Vaginal Epithelial Cell Multilayer Cultures

    Science.gov (United States)

    Rose, William A.; McGowin, Chris L.; Spagnuolo, Rae Ann; Eaves-Pyles, Tonyia D.; Popov, Vsevolod L.; Pyles, Richard B.

    2012-01-01

    The human vaginal microbiome plays a critical but poorly defined role in reproductive health. Vaginal microbiome alterations are associated with increased susceptibility to sexually-transmitted infections (STI) possibly due to related changes in innate defense responses from epithelial cells. Study of the impact of commensal bacteria on the vaginal mucosal surface has been hindered by current vaginal epithelial cell (VEC) culture systems that lack an appropriate interface between the apical surface of stratified squamous epithelium and the air-filled vaginal lumen. Therefore we developed a reproducible multilayer VEC culture system with an apical (luminal) air-interface that supported colonization with selected commensal bacteria. Multilayer VEC developed tight-junctions and other hallmarks of the vaginal mucosa including predictable proinflammatory cytokine secretion following TLR stimulation. Colonization of multilayers by common vaginal commensals including Lactobacillus crispatus, L. jensenii, and L. rhamnosus led to intimate associations with the VEC exclusively on the apical surface. Vaginal commensals did not trigger cytokine secretion but Staphylococcus epidermidis, a skin commensal, was inflammatory. Lactobacilli reduced cytokine secretion in an isolate-specific fashion following TLR stimulation. This tempering of inflammation offers a potential explanation for increased susceptibility to STI in the absence of common commensals and has implications for testing of potential STI preventatives. PMID:22412914

  8. 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...

  9. Culturing aerobic and anaerobic bacteria and mammalian cells with a microfluidic differential oxygenator.

    Science.gov (United States)

    Lam, Raymond H W; Kim, Min-Cheol; Thorsen, Todd

    2009-07-15

    In this manuscript, we report on the culture of anaerobic and aerobic species within a disposable multilayer polydimethylsiloxane (PDMS) microfluidic device with an integrated differential oxygenator. A gas-filled microchannel network functioning as an oxygen-nitrogen mixer generates differential oxygen concentration. By controlling the relative flow rate of the oxygen and nitrogen input gases, the dissolved oxygen (DO) concentration in proximal microchannels filled with culture media are precisely regulated by molecular diffusion. Sensors consisting of an oxygen-sensitive dye embedded in the fluid channels permit dynamic fluorescence-based monitoring of the DO concentration using low-cost light-emitting diodes. To demonstrate the general utility of the platform for both aerobic and anaerobic culture, three bacteria with differential oxygen requirements (E. coli, A. viscosus, and F. nucleatum), as well as a model mammalian cell line (murine embryonic fibroblast cells (3T3)), were cultured. Growth characteristics of the selected species were analyzed as a function of eight discrete DO concentrations, ranging from 0 ppm (anaerobic) to 42 ppm (fully saturated).

  10. Methanogenic archaea and sulfate reducing bacteria co-cultured on acetate: teamwork or coexistence?

    Science.gov (United States)

    Ozuolmez, Derya; Na, Hyunsoo; Lever, Mark A; Kjeldsen, Kasper U; Jørgensen, Bo B; Plugge, Caroline M

    2015-01-01

    Acetate is a major product of fermentation processes and an important substrate for sulfate reducing bacteria and methanogenic archaea. Most studies on acetate catabolism by sulfate reducers and methanogens have used pure cultures. Less is known about acetate conversion by mixed pure cultures and the interactions between both groups. We tested interspecies hydrogen transfer and coexistence between marine methanogens and sulfate reducers using mixed pure cultures of two types of microorganisms. First, Desulfovibrio vulgaris subsp. vulgaris (DSM 1744), a hydrogenotrophic sulfate reducer, was cocultured together with the obligate aceticlastic methanogen Methanosaeta concilii using acetate as carbon and energy source. Next, Methanococcus maripaludis S2, an obligate H2- and formate-utilizing methanogen, was used as a partner organism to M. concilii in the presence of acetate. Finally, we performed a coexistence experiment between M. concilii and an acetotrophic sulfate reducer Desulfobacter latus AcSR2. Our results showed that D. vulgaris was able to reduce sulfate and grow from hydrogen leaked by M. concilii. In the other coculture, M. maripaludis was sustained by hydrogen leaked by M. concilii as revealed by qPCR. The growth of the two aceticlastic microbes indicated co-existence rather than competition. Altogether, our results indicate that H2 leaking from M. concilii could be used by efficient H2-scavengers. This metabolic trait, revealed from coculture studies, brings new insight to the metabolic flexibility of methanogens and sulfate reducers residing in marine environments in response to changing environmental conditions and community compositions. Using dedicated physiological studies we were able to unravel the occurrence of less obvious interactions between marine methanogens and sulfate-reducing bacteria.

  11. Methanogenic archaea and sulfate reducing bacteria co-cultured on acetate: teamwork or coexistence?

    Directory of Open Access Journals (Sweden)

    Derya eOzuolmez

    2015-05-01

    Full Text Available Acetate is a major product of fermentation processes and an important substrate for sulfate reducing bacteria and methanogenic archaea. Most studies on acetate catabolism by sulfate reducers and methanogens have used pure cultures. Less is known about acetate conversion by mixed pure cultures and the interactions between both groups. We tested interspecies hydrogen transfer and coexistence between marine methanogens and sulfate reducers using mixed pure cultures of two types of microorganisms. First, Desulfovibrio vulgaris subsp. vulgaris (DSM 1744, a hydrogenotrophic sulfate reducer, was cocultured together with the obligate aceticlastic methanogen Methanosaeta concilii using acetate as carbon and energy source. Next, Methanococcus maripaludis S2, an obligate H2- and formate-utilizing methanogen, was used as a partner organism to M. concilii in the presence of acetate. Finally, we performed a coexistence experiment between M. concilii and an acetotrophic sulfate reducer Desulfobacter latus AcSR2. Our results showed that D. vulgaris was able to reduce sulfate and grow from hydrogen leaked by M. concilii. In the other coculture, M. maripaludis was sustained by hydrogen leaked by M. concilii as revealed by qPCR. The growth of the two aceticlastic microbes indicated co-existence rather than competition. Altogether, our results indicate that H2 leaking from M. concilii could be used by efficient H2-scavengers. This metabolic trait, revealed from coculture studies, brings new insight to the metabolic flexibility of methanogens and sulfate reducers residing in marine environments in response to changing environmental conditions and community compositions. Using dedicated physiological studies we were able to unravel the occurrence of less obvious interactions between marine methanogens and sulfate-reducing bacteria.

  12. Evaluation on factors influencing the heterotrophic growth on the soluble microbial products of autotrophs.

    Science.gov (United States)

    Ni, Bing-Jie; Zeng, Raymond J; Fang, Fang; Xie, Wen-Ming; Xu, Juan; Sheng, Guo-Ping; Sun, Yu-Jiao; Yu, Han-Qing

    2011-04-01

    In this work, the heterotrophic growth on the microbial products of autotrophs and the effecting factors were evaluated with both experimental and modeling approaches. Fluorescence in situ hybridization (FISH) analysis illustrated that ammonia oxidizers (AOB), nitrite oxidizers (NOB), and heterotrophs accounted for about 65%, 20%, and 15% of the total bacteria, respectively. The mathematical evaluation of experimental data reported in literature indicated that heterotrophic growth in nitrifying biofilm (30-50%) and granules (30%) was significantly higher than that of nitrifying sludge (15%). It was found that low influent ammonium resulted in a lower availability of soluble microbial products (SMP) and a slower heterotrophic growth, but high ammonium (>150 mg N L(-1)) feeding would lead to purely AOB dominated sludge with high biomass-associated products contained effluent, although the absolute heterotrophic growth increased. Meanwhile, the total active biomass concentration increased gradually with the increasing solids retention time, whereas the factions of active AOB, NOB, and heterotrophs varied a lot at different solids retention times. This work could be useful for better understanding of the autotrophic wastewater treatment systems.

  13. Culturable bacteria in hydroponic cultures of moss Racomitrium japonicum and their potential as biofertilizers for moss production.

    Science.gov (United States)

    Tani, Akio; Akita, Motomu; Murase, Haruhiko; Kimbara, Kazuhide

    2011-07-01

    The use of Racomitrium japonicum, a drought resistant bryophyte used for roof-greening, is gradually increasing. However, its utilization is hampered by slow growth rate. Here we isolated culturable bacteria from hydroponic cultivation samples to identify isolates that could promote moss growth. Most of the isolates belonged to Pseudomonas, Rhodococcus, and Duganella species. The isolates were biochemically characterized according to their type of interaction with plants, i.e., production of auxin, siderophores, or hydrogen cyanate, growth in the absence of an added nitrogen source, calcium phosphate solubilization, utilization of sugars, polymers, or aliphatic compounds, and antifungal activity. The isolates were applied to sterile protonemata and non-sterile adult gametophytes of R. japonicum to evaluate their effect on plant growth. Furthermore, we isolated fungi that inhibited moss growth. Our results suggest that the microbial community structure in hydroponic cultures is important to stabilize moss production and the isolates that promote moss growth have potential to be utilized as biofertilizers for moss production.

  14. Screening, growth medium optimisation and heterotrophic cultivation of microalgae for biodiesel production.

    Science.gov (United States)

    Jia, Zongchao; Liu, Ying; Daroch, Maurycy; Geng, Shu; Cheng, Jay J

    2014-08-01

    This article presents a study on screening of microalgal strains from the Peking University Algae Collection and heterotrophic cultivation for biodiesel production of a selected microalgal strain. Among 89 strains, only five were capable of growing under heterotrophic conditions in liquid cultures and Chlorella sp. PKUAC 102 was found the best for the production of heterotrophic algal biodiesel. Composition of the growth medium was optimised using response surface methodology and optimised growth conditions were successfully used for cultivation of the strain in a fermentor. Conversion of algal lipids to fatty acid methyl esters (FAMEs) showed that the lipid profile of the heterotrophically cultivated Chlorella sp. PKUAC 102 contains fatty acids suitable for biodiesel production.

  15. The capacity of some newly bacteria and fungi for biodegradation of herbicide trifluralin under agiated culture media.

    Science.gov (United States)

    Erguven, G O; Bayhan, H; Ikizoglu, B; Kanat, G; Nuhoglu, Y

    2016-05-30

    Bioremediation is the use of microorganisms to degrade environmental contaminants (pesticides, polyaromatic hydrocarbons etc.) into less toxic forms or compounds. In this study microbial biodegradation of trifluralin was performed in liquid media with 11 different types of identified fungi and bacteria cultures and their mixtures in agiated culture media. The isolated fungi and bacteria mixtures showed the highest degradation, reaching 93% in the chemical oxygen demand (COD) parameter in four days and 82% as trifluralin active ingredient in five days. Bacteria and fungi mixtures achieved 69% and 66% degradations of trifluralin active ingredient respectively. In the fungi studies, the best removal was achieved by M.Chlamydosporia at 80%, in the bacteria studies, the best removal was achieved by Bacillus simplex about 95% in five days. These different removal rates were due to the microbial differencies.

  16. Viral lysis of Phaeocystis pouchetii: implications for algal population dynamics and heterotrophic C, N and P cycling

    DEFF Research Database (Denmark)

    Haaber, Jakob Brandt Borup; Middelboe, Mathias

    2009-01-01

    A model ecosystem with two autotrophic flagellates, Phaeocystis pouchetii and Rhodomonas salina, a virus specific to P. pouchetii (PpV) and bacteria and heterotrophic nanoflagellates was used to investigate effects of viral lysis on algal population dynamics and heterotrophic nitrogen...... of virus-resistant P. pouchetii following cell lysis was observed in long-term incubations (150 days), and possibly influenced by nutrient availability and competition from R. salina. The observed impact of viral activity on autotrophic and heterotrophic processes provides direct experimental evidence...... for virus-driven nutrient generation and emphasizes the potential importance of the viral activity in supporting marine primary production....

  17. Statistical approach for the culture conditions optimization of magnetotactic bacteria for magnetic cells production

    Institute of Scientific and Technical Information of China (English)

    Li Wenbing; Yu Longjiang; Zhou Pengpeng

    2006-01-01

    The culture of Magnetospirillum magneticum WM-1 depends on several control factors that have great effect on the magnetic cells concentration. Investigation into the optimal culture conditions needs a large number of experiments. So it is desirable to minimize the number of experiments and maximize the information gained from them. The orthogonal design of experiments and mathematical statistical method are considered as effective methods to optimize the culture condition of magnetotactic bacteria WM-1 for high magnetic cells concentration. The effects of the four factors, such as pH value of medium, oxygen concentration of gas phase in the serum bottle, C:C (mtartaric acid: msuccinic acid) ratio and NaNO3 concentration, are simultaneously investigated by only sixteen experiments through the orthogonal design L16(44) method. The optimal culture condition is obtained. At the optimal culture condition ( pH 7.0, an oxygen concentration 4.0%, C: C (mtartaric acid:msuccinic acid) ratio 1:2 and NaNO3 100 mg l-1), the magnetic cells concentration is promoted to 6.5×107 cells ml-1, approximately 8.3% higher than that under the initial conditions. The pH value of medium is a very important factor for magnetic cells concentration. It can be proved that the orthogonal design of experiment is of 90% confidence. Ferric iron uptake follows Michaelis-Menten kinetics with a Km of 2.5 μM and a Vmax of 0.83 min-1.

  18. About the order in aerobic heterotrophic microbial communities from hydrocarbon-contaminated sites

    NARCIS (Netherlands)

    Becker, P.M.

    1999-01-01

    The organizational structure of communities of aerobic heterotrophic bacteria was studied by means of physiological and molecular typing of the members of arbitrary samples of isolates, ASsI. The isolate sample assay (ISA) was applied to three different hydrocarbon-polluted sites: a dry windrow pile

  19. About the order in aerobic heterotrophic microbial communities from hydrocarbon-contaminated sites

    NARCIS (Netherlands)

    Becker, P.M.

    1999-01-01

    The organizational structure of communities of aerobic heterotrophic bacteria was studied by means of physiological and molecular typing of the members of arbitrary samples of isolates, ASsI. The isolate sample assay (ISA) was applied to three different hydrocarbon-polluted sites: a dry windrow pile

  20. Enumeration of total bacteria and bacteria with genes for proteolytic activity in pure cultures and in environmental samples by quantitative PCR mediated amplification.

    Science.gov (United States)

    Bach, H-J; Tomanova, J; Schloter, M; Munch, J C

    2002-05-01

    Real-time quantitative PCR assays were developed for the absolute quantification of different groups of bacteria in pure cultures and in environmental samples. 16S rRNA genes were used as markers for eubacteria, and genes for extracellular peptidases were used as markers for potentially proteolytic bacteria. For the designed 16S rDNA TaqMan assay, specificity of the designed primer-probe combination for eubacteria, a high amplification efficiency over a wide range of starting copy numbers and a high reproducibility is demonstrated. Cell concentrations of Bacillus cereus, B. subtilis and Pseudomonas fluorescens in liquid culture were monitored by TaqMan-PCR using the 16S rDNA target sequence of Escherichia coli as external standard for quantification. Results agree with plate counts and microscopic counts of DAPI stained cells. The significance of 16S rRNA operon multiplicity to the quantification of bacteria is discussed.Furthermore, three sets of primer pair together with probe previously designed for targeting different classes of bacterial extracellular peptidases were tested for their suitability for TaqMan-PCR based quantification of proteolytic bacteria. Since high degeneracy of the probes did not allow accurate quantification, SybrGreen was used instead of molecular probes to visualize and quantify PCR products during PCR. The correlation between fluorescence and starting copy number was of the same high quality as for the 16S rDNA TaqMan assay for all the three peptidase gene classes. The detected amount of genes for neutral metallopeptidase of B. cereus, for subtilisin of B. subtilis and for alkaline metallopeptidase of P. fluorescens corresponded exactly to the numbers of bacteria investigated by the 16S rDNA targeting assay. The developed assays were applied for the quantification of bacteria in soil samples.

  1. Diversity of culturable bacteria including Pantoea in wild mosquito Aedes albopictus

    Science.gov (United States)

    2013-01-01

    Background The microbiota has been shown to play an important role in the biology of insects. In recent decades, significant efforts have been made to better understand the diversity of symbiotic bacteria associated with mosquitoes and assess their influence on pathogen transmission. Here, we report the bacterial composition found in field-caught Aedes albopictus populations by using culture-dependent methods. Results A total of 104 mosquito imagos (56 males and 48 females) were caught from four contrasting biotopes of Madagascar and their bacterial contents were screened by plating whole body homogenates on three different culture media. From 281 bacterial colony types obtained, amplified ribosomal DNA restriction analysis (ARDRA) showed they had 40 distinct ribotypes. Sequencing and BLAST analysis of the 16S rDNA genes responsible for each representative profile made it possible to identify 27 genera distributed in three major phyla. In female mosquitoes, bacterial isolates were mostly Proteobacteria (51.3%) followed by Firmicutes (30.3%) and Actinobacteria (18.4%). Conversely, Actinobacteria was the most abundant phylum in male mosquitoes (48%) followed by Proteobacteria (30.6%) and Firmicutes (20.4%). The relative abundance and composition of isolates also varied between sampling sites, ranging from 3 distinct families in Ankazobe to 8 in Tsimbazaza Park, and Toamasina and Ambohidratrimo. Pantoea was the most common genus in both females and males from all sampling sites, except for Ambohidratrimo. No differences in genome size were found between Pantoea isolates from mosquitoes and reference strains in pulse field gel electrophoresis. However, according to the numbers and sizes of plasmids, mosquito isolates clustered into three different groups with other strains isolated from insects but distinct from isolates from the environment. Conclusions The recent upsurge in research into the functional role of the insect microbiota prompts the interest to better

  2. Effect of uranium (VI) on two sulphate-reducing bacteria cultures from a uranium mine site

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Monica [Centro de Ciencias do Mar, Faculdade de Ciencias e Tecnologia, DQF, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro (Portugal); Faleiro, Maria Leonor [IBB-Centro de Biomedicina Molecular e Estrutural, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro (Portugal); Chaves, Sandra; Tenreiro, Rogerio [Universidade de Lisboa, Faculdade de Ciencias, Centro de Biodiversidade, Genomica Integrativa e Funcional (BioFIG), Campus de FCUL, Campo Grande 1749-016 Lisboa (Portugal); Costa, Maria Clara, E-mail: mcorada@ualg.pt [Centro de Ciencias do Mar, Faculdade de Ciencias e Tecnologia, DQF, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro (Portugal)

    2010-05-15

    This work was conducted to assess the impact of uranium (VI) on sulphate-reducing bacteria (SRB) communities obtained from environmental samples collected on the Portuguese uranium mining area of Urgeirica. Culture U was obtained from a sediment, while culture W was obtained from sludge from the wetland of that mine. Temperature gradient gel electrophoresis (TGGE) was used to monitor community changes under uranium stress conditions. TGGE profiles of dsrB gene fragment demonstrated that the initial cultures were composed of SRB species affiliated with Desulfovibrio desulfuricans, Desulfovibrio vulgaris and Desulfomicrobium spp. (sample U), and by species related to D. desulfuricans (sample W). A drastic change in SRB communities was observed as a result of uranium (VI) exposure. Surprisingly, SRB were not detected in the uranium removal communities. Such findings emphasize the need of monitoring the dominant populations during bio-removal studies. TGGE and phylogenetic analysis of the 16S rRNA gene fragment revealed that the uranium removal consortia are composed by strains affiliated to Clostridium genus, Caulobacteraceae and Rhodocyclaceae families. Therefore, these communities can be attractive candidates for environmental biotechnological applications associated to uranium removal.

  3. Optimization of Chlorella vulgaris and bioflocculant-producing bacteria co-culture: enhancing microalgae harvesting and lipid content.

    Science.gov (United States)

    Wang, Y; Yang, Y; Ma, F; Xuan, L; Xu, Y; Huo, H; Zhou, D; Dong, S

    2015-05-01

    Microalgae are a sustainable bioresource, and the biofuel they produce is widely considered to be an alternative to limited natural fuel resources. However, microalgae harvesting is a bottleneck in the development of technology. Axenic Chlorella vulgaris microalgae exhibit poor harvesting, as expressed by a flocculation efficiency of 0·2%. This work optimized the co-culture conditions of C. vulgaris and bioflocculant-producing bacteria in synthetic wastewater using response surface methodology (RSM), thus aiming to enhance C. vulgaris harvesting and lipid content. Three significant process variables- inoculation ratio of bacteria and microalgae, initial glucose concentration, and co-culture time- were proposed in the RSM model. F-values (3·98/8·46) and R(2) values (0·7817/0·8711) both indicated a reasonable prediction by the RSM model. The results showed that C. vulgaris harvesting efficiency reached 45·0-50·0%, and the lipid content was over 21·0% when co-cultured with bioflocculant-producing bacteria under the optimized culture conditions of inoculation ratio of bacteria and microalgae of 0·20-0·25, initial glucose concentration of microalgae harvesting and cost-effective microalgal bioproducts, and confirmed the promising prospect of introducing bioflocculant-producing bacteria into microalgae bioenergy production. This work optimized the co-culture conditions of microalgae (C. vulgaris) and bioflocculant-producing bacteria (F2, Rhizobium radiobacter) in synthetic wastewater using response surface methodology, aiming to enhance C. vulgaris harvesting and lipid produced content. Bioflocculant-producing microbes are environmentally friendly functional materials. They avoid the negative effects of traditional chemical flocculants. This work provided new insights into microalgae harvesting and cost-effective production of microalgal bioproducts, and confirmed the promising prospect of introducing bioflocculant-producing bacteria into microalgae

  4. Reduction in the structural instability of cloned eukaryotic tandem-repeat DNA by low-temperature culturing of host bacteria.

    Science.gov (United States)

    Thapana, Watcharaporn; Sujiwattanarat, Penporn; Srikulnath, Kornsorn; Hirai, Hirohisa; Koga, Akihiko

    2014-10-27

    Summary For accurate analyses of eukaryotic tandem-repeat DNA, it is often required to clone a genomic DNA fragment into a bacterial plasmid. It is, however, a serious problem that tandem-repeat DNA is frequently subjected to structural changes during maintenance or amplification in the host bacteria. Here, we show an example of a clear difference in the instability of tandem-repeat DNA between different culturing temperatures. A fragment of monkey centromeric DNA carried by pUC19 was considerably degraded by culturing bacteria at 37 °C, but the damage was reduced at 25 °C. Thus, culturing temperature is a significant factor for avoiding degradation, in addition to the genotype of the host bacteria.

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

    Science.gov (United States)

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

    2014-09-01

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

  6. Cultivation of hard-to-culture subsurface mercury-resistant bacteria and discovery of new merA gene sequences

    DEFF Research Database (Denmark)

    Rasmussen, L D; Zawadsky, C; Binnerup, S J

    2008-01-01

    was increased up to 2,800 times and numbers of mCFU were similar to the total number of mercury-resistant bacteria in the soils. Denaturing gradient gel electrophoresis analysis of DNA extracted from membranes suggested stimulation of growth of hard-to-culture bacteria during the preincubation. A total of 25......Mercury-resistant bacteria may be important players in mercury biogeochemistry. To assess the potential for mercury reduction by two subsurface microbial communities, resistant subpopulations and their merA genes were characterized by a combined molecular and cultivation-dependent approach...

  7. Abundance and diversity of culturable Pseudomonas constitute sensitive indicators for adverse long-term copper impacts in soil

    DEFF Research Database (Denmark)

    Thorsen, Maja Kristine; Brandt, Kristian Koefoed; Nybroe, Ole

    2013-01-01

    heterotrophic bacteria. This indicates that the Pseudomonas population is not resilient towards copper stress and that culturable Pseudomonas spp. comprise sensitive bio-indicators of adverse copper impacts in contaminated soils. Further this study shows that copper exposure decreases bacterial diversity...

  8. Effects of culture medium compositions on antidiabetic activity and anticancer activity of marine endophitic bacteria isolated from sponge

    Science.gov (United States)

    Maryani, Faiza; Mulyani, Hani; Artanti, Nina; Udin, Linar Zalinar; Dewi, Rizna Triana; Hanafi, Muhammad; Murniasih, Tutik

    2017-01-01

    High diversity of Indonesia marine spesies and their ability in producing secondary metabolite that can be used as a drug candidate cause this fascinating topic need to explore. Most of marine organisms explored to discover drug is macroorganism whereas microorganism (such as Indonesia marine bacteria) is very limited. Therefore, in this report, antidiabetic and anticancer activity of Indonesia marine bacteria isolated from Sponges's extract have been studied. Bacteria strain 8.9 which are collection of Research Center for Oseanography, Indonesian Institute of Sciences were from Barrang Lompo Island, Makasar, Indonesia. Bacteria were cultured in different culture medium compositions (such as: different pH, source of glucose and water) for 48 hours on a shaker, then they were extracted with ethyl asetate. Extracts of bacteria were tested by DPPH method (antioxidant activity), alpha glucosidase inhibitory activity method (antidiabetic activity), and Alamar Blue assay (anticancer activity) at 200 ppm. According to result, extract of bacteria in pH 8.0 exhibited the greatest antioxidant (19.27% inhibition), antidiabetic (63.95% inhibition) and anticancer activity of T47D cell line (44.62% cell viability) compared to other extracts. However, effect of addition of sugar sources (such as: glucose, sucrose, and soluble starch) and effect of addition of water/sea water exhibited less influence on their bioactivities. In conclusion, Indonesia marine bacteria isolated from sponge have potential a source of bioactive compound in drug discovery field.

  9. Effect of bacteria proportion on the fermentation of goat yoghurt with probiotic culture.

    Science.gov (United States)

    Shu, Guowei; Wang, Shuai; Chen, Zikun; Chen, He; Wang, Changfeng; Ma, Yaning

    2015-01-01

    Goat milk production in Shaanxi province is dominant in China, but the product is mainly infant formula and adult milk powder; product homogeneity is serious and has no goat yoghurt with probiotic culture. The effect of bacteria proportion (1:3:1, 1:2:1, 1:1:1, 2:1:1, 3:1:1) on pH, acidity, and viable counts and sensory evaluation of goat milk fermented by probiotics including L. acidophilus, B. bifidum  or L. casei besides, S. thermophilus and L. bulgaricus for developing AB-goat yoghurt and BC-goat yoghurt was investigated. The optimum bacteria proportion of L. acidophilus : B. bifidum : S. thermophilus and L. bulgaricus for AB-goat yoghurt and B. bifidum : L. casei : S. thermophilus and L. bulgaricus for BC-goat yoghurt were both 2:1:1. The pH, acidity, the viable counts of L. acidophilus and B. bifidum, the total viable counts were respectively 4.60, 7.73 (g/L), 3.50×107 cfu/mL, 3.40×107 cfu/mL and 2.30×109 cfu/mL in AB-goat yoghurt. The pH, acidity, the viable counts of B. bifidum and L. casei, the total viable counts were respectively  4.61, 8.16 (g/L), 7.60×107 cfu/mL, 5.60×107 cfu/mL and 2.04×109 cfu/mL in BC-goat yoghurt. The bacteria proportion had a significant effect on fermentation of AB- and BC-goat yoghurt, the results are beneficial for developing AB-goat yoghurt and BC-goat yoghurt.

  10. Delayed incubation as an alternative method to sample storage for enumeration of E. coli and culturable bacteria in water.

    Science.gov (United States)

    Guardabassi, L; Gravesen, J; Lund, C; Bagge, L; Dalsgaard, A

    2002-11-01

    The effects of sample storage on enumeration of Escherichia coli in marine bathing water and culturable bacteria in drinking water were evaluated. Results showed that overnight storage at 0-5 degrees C significantly reduced the counts of E. coli in bathing water (p = 0.0001) with a mean reduction of 25%. A similar effect of sample storage was observed for the enumeration of culturable bacteria in drinking water at 22 +/- 2 degrees C for 66 +/- 4 h (p = 0.0074; mean reduction = 25%) or at 36 +/- 2 degrees C for 44 +/- 4h (p = 0.0353; mean reduction = 6%). The use of a delayed incubation method, i.e. overnight storage at 0-5 degrees C of inoculated agar plates prior to incubation, did not significantly affect the counts of culturable bacteria when plates were incubated at 22 + 2 degrees C for 66 +/- 4 h, whereas it resulted in a significant increase of the bacterial numbers when plates were incubated at 36 +/- 2 degrees C for 44 +/- 4 h (p = 0.0002; mean increase = 32%). Based on these results, it is suggested to avoid the use of overnight or longer sample storage for the enumeration of E. coli in bathing water samples, as well as for the enumeration of culturable bacteria in drinking water. The delayed incubation method appears to be a reliable procedure for the enumeration of culturable bacteria and could represent a valid alternative to sample storage in order to overcome problems associated with the performance of bacteriological counts during weekends or statutory holidays. However, a multi-laboratory study is needed to evaluate the reproducibility of the delayed incubation method for the enumeration of culturable bacteria and its possible use for the enumeration of E. coli by membrane filtration.

  11. Microbial community analysis of food-spoilage bacteria in commercial custard creams using culture-dependent and independent methods.

    Science.gov (United States)

    Arakawa, K; Kawai, Y; Iioka, H; Tanioka, M; Nishimura, J; Kitazawa, H; Tsurumi, K; Saito, T

    2008-08-01

    Custard cream is made from highly nutritive raw materials such as milk and sugar and is easily spoiled by the multiplication of specific microbial contaminants or residents. However, this spoilage microbial community has not been studied. We determined the spoilage microbiota in commercial custard creams using culture-dependent and independent methods. Using the culture-dependent analysis with various agar media, 185 bacterial colonies and 43 eukaryal colonies were isolated from 7 commercial custard cream products. All bacterial isolates were morphologically, physiologically, and genetically identified as bacilli, staphylococci, lactic acid bacteria, and psychrotrophic gram-negative rods. Using culture-independent molecular analysis, the PCR-denaturing gradient gel electrophoresis technique, spoilage of the commercial custard creams was found to be caused by bacilli, staphylococci, lactic acid bacteria, psychrotrophic gram-negative rods, Anoxybacillus sp., Caurobacter sp., and Streptococcus sp. bacteria. The detected spoilage bacteria were the same species as previously detected in spoiled milk products and shown in other reports, suggesting that spoilage bacteria in a raw material easily grow in processed foods made from milk. We determined the spoilage microbial communities in commercial custard creams, and these are the first data concerning spoilage microbiota in nonfermented processed foods using a culture-independent analysis. Our study will be useful for the manufacture and safe preservation of dairy products because the first step toward safe food preservation by food manufacturers is to understand the spoilage microbiota in a target food to select optimal preservatives and to reduce the use of food additives.

  12. Studies on culture condition and extracellular hydrolase of psychrophilic bacteria from Arctic sea ice

    Institute of Scientific and Technical Information of China (English)

    Li Xiaohui; Yu Yong; Li Huirong; Zhang Lin; Jiang Xinyin; Ren Daming

    2008-01-01

    Arctic sea ice in the polar region provides a cold habitat for microbial community.Arctic sea ice microorganisms are revealed to be of considerable importance in basic research and potential in biotechnological application.This paper investigated the culture condition and extracellular hydrolase of 14 strains of different Arctic sea ice bacteria.The results showed that optimal growth temperature of strains is 15 ℃ or 20 ℃.The optimal pH is about 8.0.They hardly grow at acid condition.3% NaCl is necessary for better growth.These strains have different abilities in producing amylase,protease,cellulase and lipase.Pseudoalteronomas sp.Bsi429 and Pseudoalteronomas sp.Bsi539 produced both cellulose,protease and lipase.These results provide a basis for further developing and exploiting the cold adapted marine enzyme resources.

  13. Probiotic bacteria change Echherichia coli-induced gene expression in cultured colonocytes: Implications in intestinal pathophysiology

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    AIM: To investigate the change in eukaryotic gene expression profile in Caco-2 cells after infection with strains of Escherichia coli and commensal probiotic bacteria.METHODS: A 19200 gene/expressed sequence tag gene chip was used to examine expression of genes after infection of Caco-2 cells with strains of normal flora E.coli, Lactobacillus plantarum, and a combination of the two.RESULTS: The cDNA microarray revealed up-regulation of 155 and down-regulation of 177 genes by E. coli. L. plantarum up-regulated 45 and down-regulated 36 genes. During mixed infection, 27 genes were upregulated and 59 were down-regulated, with nullification of stimulatory/inhibitory effects on most of the genes. Expression of several new genes was noted in this group.CONCLUSION: The commensal bacterial strains used in this study induced the expression of a large number of genes in colonocyte-like cultured cells and changed the expression of several genes involved in important cellular processes such as regulation of transcription, protein biosynthesis, metabolism, cell adhesion, ubiquitination,and apoptosis. Such changes induced by the presence of probiotic bacteria may shape the physiologic and pathologic responses they trigger in the host.

  14. Ability of procalcitonin to diagnose bacterial infection and bacteria types compared with blood culture findings

    Directory of Open Access Journals (Sweden)

    Watanabe Y

    2016-09-01

    Full Text Available Yuji Watanabe,1,2 Nozomi Oikawa,1,2 Maya Hariu,1,2 Ryota Fuke,1 Masafumi Seki1 1Division of Infectious Diseases and Infection Control, 2Laboratory for Clinical Microbiology, Tohoku Medical and Pharmaceutical University Hospital, Sendai City, Miyagi, Japan Abstract: Procalcitonin (PCT and C-reactive protein serve as biomarkers of infection in patients with sepsis/bacteremia. The present study assessed the clinical characteristics of 280 patients with suspected sepsis who were admitted to Tohoku Medical and Pharmaceutical University Hospital between January 2012 and December 2013. Among the patients, 133 and 147 were positive and negative for PCT, respectively. Patients who were PCT positive were older and more frequently male, had reduced levels of platelets and albumin, and increased levels of aspartate aminotransferase, alanine aminotransferase, blood urea nitrogen, creatinine, and C-reactive protein. Patients who were PCT positive had significantly higher blood culture positivity compared with those who were PCT negative, and the sensitivity and specificity of PCT for detecting positive blood cultures were 74.5% and 59.1%, respectively. Escherichia coli was detected in PCT-positive patients, whereas Staphylococcus epidermidis and Staphylococcus lugdunensis were frequently detected in PCT-negative patients. Levels of PCT were higher in the patients infected with gram-negative rods than those with gram-positive cocci. Furthermore, extended-spectrum β-lactamase (ESBL-producing bacteria cases showed higher levels of PCT than those of non-ESBL cases. These results suggest that PCT may be a useful biomarker of sepsis, and it might serve as a strong tool to detect patients with severe gram-negative rod bacteremia including ESBL-producing bacteria cases early due to its relative high sensitivity. Keywords: biomarker, sepsis, Escherichia coli, gram-negative rods, ESBL

  15. Development of a Laboratory Model of a Phototroph-Heterotroph Mixed-Species Biofilm at the Stone/Air Interface.

    Science.gov (United States)

    Villa, Federica; Pitts, Betsey; Lauchnor, Ellen; Cappitelli, Francesca; Stewart, Philip S

    2015-01-01

    Recent scientific investigations have shed light on the ecological importance and physiological complexity of subaerial biofilms (SABs) inhabiting lithic surfaces. In the field of sustainable cultural heritage (CH) preservation, mechanistic approaches aimed at investigation of the spatiotemporal patterns of interactions between the biofilm, the stone, and the atmosphere are of outstanding importance. However, these interactions have proven difficult to explore with field experiments due to the inaccessibility of samples, the complexity of the ecosystem under investigation and the temporal resolution of the experiments. To overcome these limitations, we aimed at developing a unifying methodology to reproduce a fast-growing, phototroph-heterotroph mixed species biofilm at the stone/air interface. Our experiments underscore the ability of the dual-species SAB model to capture functional traits characteristic of biofilms inhabiting lithic substrate such as: (i) microcolonies of aggregated bacteria; (ii) network like structure following surface topography; (iii) cooperation between phototrophs and heterotrophs and cross feeding processes; (iv) ability to change the chemical parameters that characterize the microhabitats; (v) survival under desiccation and (vi) biocide tolerance. With its advantages in control, replication, range of different experimental scenarios and matches with the real ecosystem, the developed model system is a powerful tool to advance our mechanistic understanding of the stone-biofilm-atmosphere interplay in different environments.

  16. Development of a laboratory model of a phototroph-heterotroph mixed-species biofilm at the stone/air interface

    Directory of Open Access Journals (Sweden)

    Federica eVilla

    2015-11-01

    Full Text Available Recent scientific investigations have shed light on the ecological importance and physiological complexity of subaerial biofilms (SABs inhabiting lithic surfaces. In the field of sustainable cultural heritage (CH preservation, mechanistic approaches aimed at investigation of the spatiotemporal patterns of interactions between the biofilm, the stone, and the atmosphere are of outstanding importance. However, these interactions have proven difficult to explore with field experiments due to the inaccessibility of samples, the complexity of the ecosystem under investigation and the temporal resolution of the experiments.To overcome these limitations, we aimed at developing a unifying methodology to reproduce a fast-growing, phototroph-heterotroph mixed species biofilm at the stone/air interface. Our experiments underscore the ability of the dual-species SAB model to capture functional traits characteristic of biofilms inhabiting lithic substrate such as: i microcolonies of aggregated bacteria; ii network like structure following surface topography; iii cooperation between phototrophs and heterotrophs and cross feeding processes; iv ability to change the chemical parameters that characterize the microhabitats; v survival under desiccation and vi biocide tolerance. With its advantages in control, replication, range of different experimental scenarios and matches with the real ecosystem, the developed model system is a powerful tool to advance our mechanistic understanding of the stone-biofilm-atmosphere interplay in different environments.

  17. Identification and Antimicrobial Resistance of Bacteria Isolated from Probiotic Products Used in Shrimp Culture.

    Directory of Open Access Journals (Sweden)

    Gazi Md Noor Uddin

    Full Text Available Probiotics are increasingly used in aquaculture to control diseases and improve feed digestion and pond water quality; however, little is known about the antimicrobial resistance properties of such probiotic bacteria and to what extent they may contribute to the development of bacterial resistance in aquaculture ponds. Concerns have been raised that the declared information on probiotic product labels are incorrect and information on bacterial composition are often missing. We therefore evaluated seven probiotics commonly used in Vietnamese shrimp culture for their bacterial species content, phenotypic antimicrobial resistance and associated transferable resistance genes. The bacterial species was established by 16S rRNA sequence analysis of 125 representative bacterial isolates. MIC testing was done for a range of antimicrobials and whole genome sequencing of six multiple antimicrobial resistant Bacillus spp. used to identify resistance genes and genetic elements associated with horizontal gene transfer. Thirteen bacterial species declared on the probiotic products could not be identified and 11 non-declared Bacillus spp. were identified. Although our culture-based isolation and identification may have missed a few bacterial species present in the tested products this would represent minor bias, but future studies may apply culture independent identification methods like pyro sequencing. Only 6/60 isolates were resistant to more than four antimicrobials and whole genome sequencing showed that they contained macrolide (ermD, tetracycline (tetL, phenicol (fexA and trimethoprim (dfrD, dfrG and dfrK resistance genes, but not known structures associated with horizontal gene transfer. Probiotic bacterial strains used in Vietnamese shrimp culture seem to contribute with very limited types and numbers of resistance genes compared to the naturally occurring bacterial species in aquaculture environments. Approval procedures of probiotic products must be

  18. Identification and Antimicrobial Resistance of Bacteria Isolated from Probiotic Products Used in Shrimp Culture.

    Science.gov (United States)

    Noor Uddin, Gazi Md; Larsen, Marianne Halberg; Christensen, Henrik; Aarestrup, Frank M; Phu, Tran Minh; Dalsgaard, Anders

    2015-01-01

    Probiotics are increasingly used in aquaculture to control diseases and improve feed digestion and pond water quality; however, little is known about the antimicrobial resistance properties of such probiotic bacteria and to what extent they may contribute to the development of bacterial resistance in aquaculture ponds. Concerns have been raised that the declared information on probiotic product labels are incorrect and information on bacterial composition are often missing. We therefore evaluated seven probiotics commonly used in Vietnamese shrimp culture for their bacterial species content, phenotypic antimicrobial resistance and associated transferable resistance genes. The bacterial species was established by 16S rRNA sequence analysis of 125 representative bacterial isolates. MIC testing was done for a range of antimicrobials and whole genome sequencing of six multiple antimicrobial resistant Bacillus spp. used to identify resistance genes and genetic elements associated with horizontal gene transfer. Thirteen bacterial species declared on the probiotic products could not be identified and 11 non-declared Bacillus spp. were identified. Although our culture-based isolation and identification may have missed a few bacterial species present in the tested products this would represent minor bias, but future studies may apply culture independent identification methods like pyro sequencing. Only 6/60 isolates were resistant to more than four antimicrobials and whole genome sequencing showed that they contained macrolide (ermD), tetracycline (tetL), phenicol (fexA) and trimethoprim (dfrD, dfrG and dfrK) resistance genes, but not known structures associated with horizontal gene transfer. Probiotic bacterial strains used in Vietnamese shrimp culture seem to contribute with very limited types and numbers of resistance genes compared to the naturally occurring bacterial species in aquaculture environments. Approval procedures of probiotic products must be strengthened

  19. Heterotrophic bacterial populations in tropical sandy beaches

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, S.; LokaBharathi, P.A.

    Distribution pattern of heterotrophic bacterial flora of three sandy beaches of the west coast of India was studied. The population in these beaches was microbiologically different. Population peaks of halotolerant and limnotolerant forms were...

  20. Intense association of non-culturable endophytic bacteria with antibiotic-cleansed in vitro watermelon and their activation in degenerating cultures.

    Science.gov (United States)

    Thomas, Pious

    2011-12-01

    The study was undertaken with a view to unravel the source of bacterial colony growth observed in a section of micropropagated triploid watermelon cultures that were supposedly cleansed of the associated endophytic bacteria through antibiotic treatment, and thereafter maintained under stringent sterility checks to prevent lateral intrusion of contaminants. Five different bacteria were retrieved from colony growth-displaying watermelon cultures that were previously treated with gentamycin and five isolates from cefazolin-treated stocks with the organisms showing tolerance to the respective antibiotic. These watermelon cultures were in degeneration phase (over 6 months after the previous sub-culturing), while the actively maintained counterpart stocks appeared healthy with no colony growth on different bacteriological media during tissue-screenings. The latter cultures, however, revealed abundant motile, tetrazolium-stained bacterial cells in microscopy, suggesting tissue colonization by non-culturable endophytes. PCR screening on healthy cultures endorsed tissue colonization by different bacterial phylogenic groups. A few organisms could be activated to cultivation from healthy watermelon stocks through host tissue extract supplementation, which also enhanced the growth of all the organisms. The study indicated that a fraction of antibiotic-tolerant bacteria survived intra-tissue in non-culturable form during the preceding cleansing activity, multiplied to substantial numbers thereafter, and turned cultivable in degenerating cultures contributed by tissue breakdown products. This study brings out the existence of a deep endophyte association in tissue cultures which is not easily dissociable. It also signifies the utility of in vitro system for investigations into plant-endophyte association and to bring normally non-culturable novel organisms to cultivation facilitating their future exploitation.

  1. Wastewater nutrient removal in a mixed microalgae-bacteria culture: effect of light and temperature on the microalgae-bacteria competition.

    Science.gov (United States)

    González-Camejo, J; Barat, R; Pachés, M; Murgui, M; Seco, A; Ferrer, J

    2017-03-27

    The aim of this study was to evaluate the effect of light intensity and temperature on nutrient removal and biomass productivity in a microalgae-bacteria culture and their effects on the microalgae-bacteria competition. Three experiments were carried out at constant temperature and various light intensities: 40, 85 and 125 µE m(-2) s(-1). Other two experiments were carried out at variable temperatures: 23 ± 2°C and 28 ± 2°C at light intensity of 85 and 125 µE m(-2) s(-1), respectively. The photobioreactor was fed by the effluent from an anaerobic membrane bioreactor. High nitrogen and phosphorus removal efficiencies (about 99%) were achieved under the following operating conditions: 85-125 µE m(-2) s(-1) and 22 ± 1°C. In the microalgae-bacteria culture studied, increasing light intensity favoured microalgae growth and limited the nitrification process. However, a non-graduated temperature increase (up to 32°C) under the light intensities studied caused the proliferation of nitrifying bacteria and the nitrite and nitrate accumulation. Hence, light intensity and temperature are key parameters in the control of the microalgae-bacteria competition. Biomass productivity significantly increased with light intensity, reaching 50.5 ± 9.6, 80.3 ± 6.5 and 94.3 ± 7.9 mgVSS L(-1) d(-1) for a light intensity of 40, 85 and 125 µE m(-2) s(-1), respectively.

  2. Bioalteration of synthetic Fe(III)-, Fe(II)-bearing basaltic glasses and Fe-free glass in the presence of the heterotrophic bacteria strain Pseudomonas aeruginosa: Impact of siderophores

    Science.gov (United States)

    Perez, Anne; Rossano, Stéphanie; Trcera, Nicolas; Huguenot, David; Fourdrin, Chloé; Verney-Carron, Aurélie; van Hullebusch, Eric D.; Guyot, François

    2016-09-01

    This study aims to evaluate the role of micro-organisms and their siderophores in the first steps of the alteration processes of basaltic glasses in aqueous media. In this regard, three different types of glasses - with or without iron, in the reduced Fe(II) or oxidized Fe(III) states - were prepared on the basis of a simplified basaltic glass composition. Control and Pseudomonas aeruginosa inoculated experiments were performed in a buffered (pH 6.5) nutrient depleted medium to stimulate the production of the pyoverdine siderophore. Results show that the presence of P. aeruginosa has an effect on the dissolution kinetics of all glasses as most of the calculated elemental release rates are increased compared to sterile conditions. Reciprocally, the composition of the glass in contact with P. aeruginosa has an impact on the bacterial growth and siderophore production. As an essential nutrient for this microbial strain, Fe notably appears to play a central role during biotic experiments. Its presence in the glass stimulates the bacterial growth and minimizes the synthesis of pyoverdine. Moreover the initial Fe2+/Fe3+ ratio in the glasses modulates this synthesis, as pyoverdine is not detected at all in the system in contact with Fe(III)-bearing glass. Finally, the dissolution rates appear to be correlated to siderophore concentrations as they increase with respect to sterile experiments in the order Fe(III)-bearing glass < Fe(II)-bearing glass < Fe-free glass. This increase is attributed to complexation reactions between siderophores and Fe or Al for Fe(II)-bearing glass or Fe-free glass, respectively. The dissolution of an Fe-free glass is significantly improved in the presence of bacteria, as initial dissolution rates are increased by a factor of 3. This study attests to the essential role of siderophores in the P. aeruginosa-promoted dissolution processes of basaltic glasses as well as to the complex relationships between the nutritional potential of the glass and

  3. Identification, isolation and quantification of representative bacteria from fermented cassava dough using an integrated approach of culture-dependent and culture-independent methods.

    Science.gov (United States)

    Miambi, Edouard; Guyot, Jean-Pierre; Ampe, Frédéric

    2003-04-25

    The use of denaturing gradient gel electrophoresis (DGGE) and traditional culture-depending methods for examining the bacterial community of traditional cassava starch fermentation were investigated. It appeared that DGGE profiles of total DNA of cassava dough exhibited 10 distinguishable bands. In contrast, DGGE fingerprints of bacteria recovered from enrichment cultures of fermented dough gave variable profiles containing fewer bands. Bands corresponding to five bacterial species detected by direct PCR-DGGE of total DNA from of cassava dough were also observed in DGGE patterns of enrichment cultures. Eighteen strains were isolated from cultures selected on the basis of their DGGE banding patterns. Assessment of bacterial identification by 16S rDNA sequence similarity revealed that band comigration implied sequence identity. Comparison of 16S rDNA sequences of excised DGGE bands and recovered pure culture isolates with those in GENBANK and the RDP databases revealed that representative bacteria of fermented cassava dough were Lactobacillus and Pediococcus species as well as species of Clostridium, Propionibacterium and Bacillus. Some Lactobacillus species detected in dough samples by sequence analysis of DGGE bands were not recovered in any of the five culture media and conditions used. On the other hand, some species recovered as pure cultures from enrichments were not detected by direct DGGE analysis of total bacterial DNA from cassava dough. Our results provide evidence of the necessity to combine both culture-dependent and culture-independent methods for better description of microbial communities in indigenous cassava starch fermentations.

  4. 茶园一株异养硝化-好氧脱氮菌的鉴定及特性研究%and characterization of a heterotrophic nitrification-aerobic denitrification bacteria from tea garden

    Institute of Scientific and Technical Information of China (English)

    韩晓阳; 王乃栋; 于亚伟; 张丽霞

    2012-01-01

    By the experimental procedure of enrichment culture and purification, one bacterial strain F1 was screened from the soil of tea garden in Shandong province. The strain was identified as Flavobacterium sp. , on the base of 16S rRNA sequencing analysis and physiological & biochemistry tests as well as the observation of negative staining electron microscopy. The nitrification performance and denitrification ability were studied and the results showed that while using organic matter, strain F1 has the function of both nitrification and denitrification. After 60 h culture, ammonia nitrogen removal rate reached 84.54% and nitrite nitrogen removal rate reached 91.87% in the nitrifying medium; ammonia nitrogen removal rate reached 79. 17% and nitrite nitrogen removal rate reached 84. 30% in the denitrifying medium; the denitrification capacity of ammonium nitrogen was the strongest under the conditions of the initial nitrogen.%经过菌株富集培养、分离纯化等一系列步骤,从山东茶园土壤中筛选出一株菌株F1,通过对其进行16SrRNA测序及生理生化指标的测定,结合负染电镜观察结果,参照《伯杰细菌鉴定手册》鉴定该菌株属于黄杆菌属。同时对其硝化和反硝化脱氮能力进行了研究。结果表明,菌株F1能在利用有机物的同时进行硝化和反硝化脱氮作用。经过60h的培养,在硝化培养基上对氨氮的去除率达到84.54%,对亚硝酸盐的去除率达到91.87%;在反硝化培养基上对硝酸盐的去除率达到79.17%,对亚硝酸盐的去除率达到84.30%;在以铵态氮为初始氮源的条件下脱氮能力最强。

  5. Application of culture culture-independent molecular biology based methods to evaluate acetic acid bacteria diversity during vinegar processing.

    Science.gov (United States)

    Ilabaca, Carolina; Navarrete, Paola; Mardones, Pamela; Romero, Jaime; Mas, Albert

    2008-08-15

    Acetic acid bacteria (AAB) are considered fastidious microorganisms because they are difficult to isolate and cultivate. Different molecular approaches were taken to detect AAB diversity, independently of their capacity to grow in culture media. Those methods were tested in samples that originated during traditional vinegar production. Bacterial diversity was assessed by analysis of 16S rRNA gene, obtained by PCR amplifications of DNA extracted directly from the acetification container. Bacterial composition was analyzed by RFLP-PCR of 16S rRNA gene, Temporal Temperature Gradient Gel Electrophoresis (TTGE) separation of amplicons containing region V3-V5 of 16S rRNA gene and cloning of those amplicons. TTGE bands and clones were grouped based on their electrophoretic pattern similarity and sequenced to be compared with reference strains. The main microorganism identified in vinegar was Acetobacter pasteurianus, which at the end of the acetification process was considered to be the only microorganism present. The diversity was the highest at 2% acetic acid, where indefinite species of Gluconacetobacter xylinus/europaeus/intermedius were also present.

  6. Effect of culture medium on acid production from sorbitol by oral bacteria.

    Science.gov (United States)

    Kalfas, S; Edwardsson, S

    1990-08-01

    The fermentation of sorbitol or glucose and the acid production by strains belonging to the genera Actinomyces, Lactobacillus, and Streptococcus isolated from the predominant sorbitol-fermenting human dental plaque flora were studied in cultures in complex or defined bacteriologic broths and in saliva-based broth. The growth yields of Lactobacillus and Streptococcus in the saliva-based media and of Actinomyces in the defined broth were poor. Addition of fermentable carbohydrate to the saliva-based broth favored the growth of Streptococcus and Lactobacillus but not that of Actinomyces. The results showed obvious differences in the capacity of oral bacteria to ferment sorbitol between cultures in saliva-based and bacteriologic broths. Lactobacillus failed to utilize sorbitol when saliva was the only source of nutrients. Lower proportions of lactic and formic acids were formed from sorbitol by Actinomyces and Lactobacillus in the saliva-based than in the bacteriologic media. The findings illustrate some mechanisms possibly involved in the interactions between sorbitol and dental plaque flora.

  7. Biological activity of a red-tide alga--A. tamarense under co-cultured condition with bacteria

    Institute of Scientific and Technical Information of China (English)

    SU Jian-qiang; YU Zhi-ming; TIAN Yun; SONG Xiu-xian; HONG Hua-sheng; ZHENG Tian-ling

    2005-01-01

    The relationship between Alexandrium tamarense(Lebour) Balech, one of red-tide alga, and two strains of marine bacteria,Bacillius megaterium(S7 ) and B. halmapulus(S10) isolated from Xiamen Western Sea, was investigated by evaluating the growth state of A. tamarense and the variation of β-glucosidase activity in co-culture system. The results showed the growth and multiplication of the alga were related with the concentration, genus speciality of the bacteria, and growth stage of the alga itself. The growth of A. tamarense was obviously inhibited by S7 and S10 at high concentration. Either inhibition or promotion contributed much more clearly in earlier than in later stage of the growth of the alga. Furthermore, there was a roughly similar variation trend of the activity of extra-cellular enzyme, β-glucosidase, in the water of the separately co-cultured bacteria S7 and S10 with the alga. The β-glucosidase activity(β-GlcA) rapidly increased during the later algal growth accompanying the increase of the lysis of the alga cells. The obvious inhibition of A. tamarense by marine bacteria at high concentration and evident increase of β-GlcA in co-colture system would help us in better understanding the relationship between red-tide alga and bacteria, and also enlightened us the possible use of bacteria in the bio-control of red-tide.

  8. Functionalized arrays of Raman-enhancing nanoparticles for capture and culture-free analysis of bacteria in human blood

    Science.gov (United States)

    Liu, Ting-Yu; Tsai, Kun-Tong; Wang, Huai-Hsien; Chen, Yu; Chen, Yu-Hsuan; Chao, Yuan-Chun; Chang, Hsuan-Hao; Lin, Chi-Hung; Wang, Juen-Kai; Wang, Yuh-Lin

    2011-11-01

    Detecting bacteria in clinical samples without using time-consuming culture processes would allow rapid diagnoses. Such a culture-free detection method requires the capture and analysis of bacteria from a body fluid, which are usually of complicated composition. Here we show that coating Ag-nanoparticle arrays with vancomycin (Van) can provide label-free analysis of bacteria via surface-enhanced Raman spectroscopy (SERS), leading to a ~1,000-fold increase in bacteria capture, without introducing significant spectral interference. Bacteria from human blood can be concentrated onto a microscopic Van-coated area while blood cells are excluded. Furthermore, a Van-coated substrate provides distinctly different SERS spectra of Van-susceptible and Van-resistant Enterococcus, indicating its potential use for drug-resistance tests. Our results represent a critical step towards the creation of SERS-based multifunctional biochips for rapid culture- and label-free detection and drug-resistant testing of microorganisms in clinical samples.

  9. Detection of periodontopathogenic bacteria in pregnant women by traditional anaerobic culture method and by a commercial molecular genetic method.

    Science.gov (United States)

    Urbán, Edit; Terhes, Gabriella; Radnai, Márta; Gorzó, István; Nagy, Elisabeth

    2010-06-01

    To culture facultative and strict anaerobic bacteria is a well-established method for analyzing subgingival plaque samples. Micro-IDent and micro-IDent Plus (HAIN Lifescience GmbH, Nehren, Germany) tests are two commercially available rapid PCR-based methods for the identification and quantification of putative periodontopathogen bacteria. In this study, we compared these commercial PCR-based hybridization methods with conventional anaerobic culture technique. A total of 36 subgingival plaque samples were collected from periodontal pockets of pregnant women with chronic localized periodontitis. Aliquots of these samples were evaluated with species-specific probes provided by micro-IDent and micro-IDent Plus tests simultaneously, and from the same samples anaerobic and capnophylic bacteria were cultured on selective media. The overall agreement between both methods was excellent for Eubacterium nodatum, Tannerella forsythia and Porphyromonas gingivalis (97-92%), fair for Capnocytophaga sp, Eikenella corrodens, Actinobacillus actinomycetemcomitans, and Prevotella intermedia (91-89%) and poor for Fusobacterium nucleatum, Parvimonas micra (Micromonas micros), and Campylobacter rectus (86-78%). Discrepancies in the results may be explained by inability of culture method to distinguish between closely related taxa (e.i P. intermedia/Prevotella. nigrescens), and problems of keeping periodontopathogen bacteria viable, which is required for successful detection by standard culture method. Nucleic acid-based methods may replace cultivation method as frequently used methods in microbiological diagnosis of progressive periodontitis, thus micro-IDent and micro-IDent Plus tests can be recommended where culture of periodontopathogenic bacteria is not performed in routine microbiology laboratories to analyze subgingival plaque samples.

  10. Modelling the effect of lactic acid bacteria from starter- and aroma culture on growth of Listeria monocytogenes in cottage cheese.

    Science.gov (United States)

    Østergaard, Nina Bjerre; Eklöw, Annelie; Dalgaard, Paw

    2014-10-01

    Four mathematical models were developed and validated for simultaneous growth of mesophilic lactic acid bacteria from added cultures and Listeria monocytogenes, during chilled storage of cottage cheese with fresh- or cultured cream dressing. The mathematical models include the effect of temperature, pH, NaCl, lactic- and sorbic acid and the interaction between these environmental factors. Growth models were developed by combining new and existing cardinal parameter values. Subsequently, the reference growth rate parameters (μref at 25°C) were fitted to a total of 52 growth rates from cottage cheese to improve model performance. The inhibiting effect of mesophilic lactic acid bacteria from added cultures on growth of L. monocytogenes was efficiently modelled using the Jameson approach. The new models appropriately predicted the maximum population density of L. monocytogenes in cottage cheese. The developed models were successfully validated by using 25 growth rates for L. monocytogenes, 17 growth rates for lactic acid bacteria and a total of 26 growth curves for simultaneous growth of L. monocytogenes and lactic acid bacteria in cottage cheese. These data were used in combination with bias- and accuracy factors and with the concept of acceptable simulation zone. Evaluation of predicted growth rates of L. monocytogenes in cottage cheese with fresh- or cultured cream dressing resulted in bias-factors (Bf) of 1.07-1.10 with corresponding accuracy factor (Af) values of 1.11 to 1.22. Lactic acid bacteria from added starter culture were on average predicted to grow 16% faster than observed (Bf of 1.16 and Af of 1.32) and growth of the diacetyl producing aroma culture was on average predicted 9% slower than observed (Bf of 0.91 and Af of 1.17). The acceptable simulation zone method showed the new models to successfully predict maximum population density of L. monocytogenes when growing together with lactic acid bacteria in cottage cheese. 11 of 13 simulations of L

  11. Production of NO and N2O by Pure Cultures of Nitrifying and Denitrifying Bacteria during Changes in Aeration

    NARCIS (Netherlands)

    Kester, R.A.; Boer, W. de; Laanbroek, H.J.

    1997-01-01

    Peak emissions of NO and N2O are often observed after wetting of soil. The reactions to sudden changes in the aeration of cultures of nitrifying and denitrifying bacteria with respect to NO and N2O emissions were compared to obtain more information about the microbiological aspects of peak emissions

  12. Influence of Dilution Rate on Enzymes of Intermediary Metabolism in Two Freshwater Bacteria Grown in Continuous Culture

    NARCIS (Netherlands)

    Matin, A.; Grootjans, A.; Hogenhuis, H.

    1976-01-01

    Two freshwater bacteria, a Pseudomonas sp. and a Spirillum sp., were grown in continuous culture under steady-state conditions in L-lactate-, succinate-, ammonium- or phosphate-limited media. In Pseudomonas sp., NAD-independent and NAD-dependent L-lactate dehydrogenases, aconitase, isocitrate dehydr

  13. Toward Probiotict Food Product from Meat Through Isolation and Identification Lactic Acid Bacteria As Probiotic Culture Stater

    Directory of Open Access Journals (Sweden)

    Yunilas Yunilas

    2014-01-01

    Full Text Available Probiotic food products of meat can provide extensive benefits, to increase the shelf life and nutritional value also improve the taste. The use of lactic acid bacteria culture (LAB derived from the isolation of the meat and the addition of probiotic cultures (Lactobacilli and Bifidobacteria in fermented sausage processing is expected to produce a probiotic sausage products with nutritional value, and better shelf life and improve health. This study aimed to isolate and identify lactic acid bacteria (LAB of meat as a starter culture fermented sausages. The parameters observed were gram test, catalase, motility, gas production, type of fermentation, growth at various temperatures and pH. The results were obtained 28 isolates, 17 isolates were able to produce acid and 8 of them are lactic acid bacteria (LAB with the characteristics of gram-positive, catalase negative, not motile, produces gas, are hetero and homo fermentative, optimum growth temperature of 300C and a few of them are able to grow on pH 3.5. Lactic acid bacteria that able to be combined with probiotics as sausage starter culture to the probiotic food products of meat.

  14. Dilution-to-extinction culturing of SAR11 members and other marine bacteria from the Red Sea

    KAUST Repository

    Mohamed, Roslinda B.

    2013-12-01

    Life in oceans originated about 3.5 billion years ago where microbes were the only life form for two thirds of the planet’s existence. Apart from being abundant and diverse, marine microbes are involved in nearly all biogeochemical processes and are vital to sustain all life forms. With the overgrowing number of data arising from culture-independent studies, it became necessary to improve culturing techniques in order to obtain pure cultures of the environmentally significant bacteria to back up the findings and test hypotheses. Particularly in the ultra-oligotrophic Red Sea, the ubiquitous SAR11 bacteria has been reported to account for more than half of the surface bacterioplankton community. It is therefore highly likely that SAR11, and other microbial life that exists have developed special adaptations that enabled them to thrive successfully. Advances in conventional culturing have made it possible for abundant, unculturable marine bacteria to be grown in the lab. In this study, we analyzed the effectiveness of the media LNHM and AMS1 in isolating marine bacteria from the Red Sea, particularly members of the SAR11 clade. SAR11 strains obtained from this study AMS1, and belonged to subgroup 1a and phylotype 1a.3. We also obtained other interesting strains which should be followed up with in the future. In the long run, results from this study will enhance our knowledge of the pelagic ecosystem and allow the impacts of rising temperatures on marine life to be understood.

  15. 16S rRNA gene sequencing in routine identification of anaerobic bacteria isolated from blood cultures

    DEFF Research Database (Denmark)

    Justesen, Ulrik Stenz; Skov, Marianne Nielsine; Knudsen, Elisa;

    2010-01-01

    A comparison between conventional identification and 16S rRNA gene sequencing of anaerobic bacteria isolated from blood cultures in a routine setting was performed (n = 127). With sequencing, 89% were identified to the species level, versus 52% with conventional identification. The times...

  16. ISOLATION OF TYPICAL MARINE-BACTERIA BY DILUTION CULTURE - GROWTH, MAINTENANCE, AND CHARACTERISTICS OF ISOLATES UNDER LABORATORY CONDITIONS

    NARCIS (Netherlands)

    SCHUT, F; DEVRIES, EJ; GOTTSCHAL, JC; ROBERTSON, BR; HARDER, W; PRINS, R A; BUTTON, DK

    Marine bacteria in Resurrection Bay near Seward, Alaska, and in the central North Sea off the Dutch coast were cultured in filtered autoclaved seawater following dilution to extinction. The populations present before dilution varied from 0.11 x 10(9) to 1.07 x 10(9) cells per liter. The mean cell

  17. Improving the culturability of freshwater bacteria using FW70, a low-nutrient solid medium amended with sodium pyruvate.

    Science.gov (United States)

    Imazaki, Iori; Kobori, Youichi

    2010-04-01

    Bacterial culture based on the use of plate media is an effective method for investigating bacterial populations in the environment. To improve the culturability of bacteria from freshwater lakes, we developed a new medium, FW70, which contains sodium pyruvate, casamino acids, and lake water and is solidified using gellan gum. To test the importance of these components, we prepared a series of media in which one or more of the components was absent. Water was sampled 31 times from 3 Japanese lakes and was passed through a membrane filter (pore size = 0.45 microm) to remove fast-growing microbes before the water was spread onto the plates. In most cases, significantly larger numbers of bacterial colonies were detected on FW70 than on other media. Furthermore, to test the practicality of FW70, we compared it with standard nutrient agar and R2A agar. In all cases, the culturability was significantly greater on FW70 than on standard nutrient agar or R2A agar. Some isolates recovered by means of FW70 belonged to bacteria that had not previously been classified. These results suggest that FW70 improves the culturability of freshwater bacteria and can be used for the isolation of novel bacteria as a result of the filtration step.

  18. Multicenter evaluation of the Verigene Gram-negative blood culture nucleic acid test for rapid detection of bacteria and resistance determinants in positive blood cultures.

    Science.gov (United States)

    Uno, Naoki; Suzuki, Hiromichi; Yamakawa, Hiromi; Yamada, Maiko; Yaguchi, Yuji; Notake, Shigeyuki; Tamai, Kiyoko; Yanagisawa, Hideji; Misawa, Shigeki; Yanagihara, Katsunori

    2015-12-01

    The Verigene Gram-Negative Blood Culture Nucleic Acid Test (BC-GN) is a microarray-based assay that enables rapid detection of 9 common Gram-negative bacteria and 6 resistance determinants directly from positive blood cultures. We compared the performance of BC-GN with currently used automated systems, testing 141 clinical blood cultures and 205 spiked blood cultures. For identification of BC-GN target organisms in clinical and spiked blood cultures, the BC-GN assay showed 98.5% (130/132) and 98.9% (182/184) concordance, respectively. Of 140 resistance genes positively detected in clinical and spiked blood cultures with the BC-GN test, 139 (99.3%) were confirmed by PCR, and the detection results were consistent with the resistance phenotypes observed. The BC-GN assay, thus, can potentially improve care for sepsis patients by enabling timely detection and targeted antimicrobial therapy.

  19. Effects of ultraviolet light disinfection on tetracycline-resistant bacteria in wastewater effluents.

    Science.gov (United States)

    Childress, H; Sullivan, B; Kaur, J; Karthikeyan, R

    2014-09-01

    The ubiquitous use of antibiotics has led to an increasing number of antibiotic-resistant bacterial strains, including strains that are multidrug-resistant, pathogenic, or both. There is also evidence to suggest that antibiotic resistance genes (ARGs) spread to the environment, humans, and animals through wastewater effluents. The overall objective of this study was to investigate the effect of ultraviolet (UV) light disinfection on antibiotic-resistant bacteria. Wastewater effluent samples from a wastewater treatment plant (WWTP) in Texas were evaluated for differences in tetracycline-resistant bacteria before and after UV treatment. The effects of photoreactivation or dark repair on the reactivation of bacteria present in WWTP effluent after UV disinfection were also examined. Culture-based methods were used to characterize viable heterotrophic, tetracycline-resistant heterotrophic, Escherichia coli, and tetracycline-resistant E. coli bacteria present before and after UV treatment. UV disinfection was found to be as effective at reducing concentrations of resistant heterotrophs and E. coli, as it was at reducing total bacterial concentrations. The lowest survival ratio following UV disinfection was observed in tetracycline-resistant E. coli showing particular susceptibility to UV treatment. Photoreactivation and dark repair rates were found to be comparable to each other for all bacterial populations.

  20. Culture-based Identification Of Microcystin-Degrading Bacteria In the Sandusky Bay and Maumee Bay of Lake Erie

    Science.gov (United States)

    Ormiston, A.; Mou, X.

    2012-12-01

    for this research include a comparison of MC-degrading bacteria in different habitats, and investigating the interactions between heterotrophic bacteria, cyanobacteria and zooplankton during CyanoHABs.

  1. Impact of succinate on growth of cultures of cecal bacteria from commercial broilers

    Science.gov (United States)

    Beneficial bacteria in probiotics produce and utilize several organic acids that may play a role in the ability of these bacteria to inhibit colonization of poultry by enteropathogens. Since cecal contents of adult poultry contain many of these beneficial bacteria, 3 experiments were conducted to ex...

  2. Aerobic bacteria cultured from the mouth of the American opossum (Didelphis virginiana) with reference to bacteria associated with bite infections.

    OpenAIRE

    Howell, J. M.; Dalsey, W C

    1990-01-01

    The American opossum inflicts bite injuries both when hunted for food and when accidentally provoked when handled in captivity. This study involved aerobically culturing organisms from the mouths of seven wild opossums (Didelphis virginiana). Isolates included streptococci, coagulase-positive and -negative staphylococci, Aeromonas spp., Citrobacter freundii, Eikenella corrodens, and Escherichia coli.

  3. BIOCHEMICAL CHARACTERISTICS OF LACTIC ACID PRODUCING BACTERIA AND PREPARATION OF CAMEL MILK CHEESE BY USING STARTER CULTURE

    Directory of Open Access Journals (Sweden)

    T. Ahmed and R. Kanwal

    2004-04-01

    Full Text Available Lactic acid bacteria (LAB were isolated from camel milk by culturing the milk on specific media and pure culture was obtained by sub-culturing. Purification of culture was confirmed by Gram’s staining and identified by different biochemical tests. Camel milk contained lactic acid producing bacteria like Streptococci such as S. cremoris and S. lactis and Lactobacilli such as L. acidophilus. L. acidophilus grew more rapidly in camel milk than others as its growth was supported by camel milk. Ability of each strain was tested to convert lactose of milk into lactic acid. It was observed that 66% lactose was converted by S. lactis 20, whereas S. cremoris 22 and L. acidophilus 23 converted 56 and 74% lactose into lactic acid, respectively. Effect of freeze-drying was also recorded and the results showed that in all cases there was a slight decrease in the cell count before and after the freeze-drying. The decrease was approximately 0.47, 0.078 and 0.86% for S. lactis 20, S. cremoris 22 and L. acidophilus 23, respectively. Starter culture was prepared from strains isolated from camel milk. Camel and buffalo milk cheese was prepared by using starter culture. The strains isolated from camel milk were best for acid production and coagulated the milk in less time. It is concluded that cheese can be prepared successfully from camel milk and better results can be obtained by coagulating milk with starter culture.

  4. Culturable diversity and functional annotation of psychrotrophic bacteria from cold desert of Leh Ladakh (India).

    Science.gov (United States)

    Yadav, Ajar Nath; Sachan, Shashwati Ghosh; Verma, Priyanka; Tyagi, Satya Prakash; Kaushik, Rajeev; Saxena, Anil K

    2015-01-01

    To study culturable bacterial diversity under subzero temperature conditions and their possible functional annotation, soil and water samples from Leh Ladakh region were analysed. Ten different nutrient combinations were used to isolate the maximum possible culturable morphotypes. A total of 325 bacterial isolates were characterized employing 16S rDNA-Amplified Ribosomal DNA Restriction Analysis with three restriction endonucleases AluI, MspI and HaeIII, which led to formation of 23-40 groups for the different sites at 75 % similarity index, adding up to 175 groups. Phylogenetic analysis based on 16S rRNA gene sequencing led to the identification of 175 bacteria, grouped in four phyla, Firmicutes (54 %), Proteobacteria (28 %), Actinobacteria (16 %) and Bacteroidetes (3 %), and included 29 different genera with 57 distinct species. Overall 39 % of the total morphotypes belonged to the Bacillus and Bacillus derived genera (BBDG) followed by Pseudomonas (14 %), Arthrobacter (9 %), Exiguobacterium (8 %), Alishewanella (4 %), Brachybacterium, Providencia, Planococcus (3 %), Janthinobacterium, Sphingobacterium, Kocuria (2 %) and Aurantimonas, Citricoccus, Cellulosimicrobium, Brevundimonas, Desemzia, Flavobacterium, Klebsiella, Paracoccus, Psychrobacter, Sporosarcina, Staphylococcus, Sinobaca, Stenotrophomonas, Sanguibacter, Vibrio (1 %). The representative isolates from each cluster were screened for their plant growth promoting characteristics at low temperature (5-15 °C). Variations were observed among strains for production of ammonia, hydrogen cyanide, indole-3-acetic acid and siderophore, solubilisation of phosphate, 1-aminocyclopropane-1-carboxylate deaminase activity and biocontrol activity against Rhizoctonia solani and Macrophomina phaseolina. Cold adapted microbes may have application as inoculants and biocontrol agents in crops growing at high altitudes under cold climate condition.

  5. Nitrogen source effects on the denitrifying anaerobic methane oxidation culture and anaerobic ammonium oxidation bacteria enrichment process.

    Science.gov (United States)

    Fu, Liang; Ding, Jing; Lu, Yong-Ze; Ding, Zhao-Wei; Zeng, Raymond J

    2017-05-01

    The co-culture system of denitrifying anaerobic methane oxidation (DAMO) and anaerobic ammonium oxidation (Anammox) has a potential application in wastewater treatment plant. This study explored the effects of permutation and combination of nitrate, nitrite, and ammonium on the culture enrichment from freshwater sediments. The co-existence of NO3(-), NO2(-), and NH4(+) shortened the enrichment time from 75 to 30 days and achieved a total nitrogen removal rate of 106.5 mg/L/day on day 132. Even though ammonium addition led to Anammox bacteria increase and a higher nitrogen removal rate, DAMO bacteria still dominated in different reactors with the highest proportion of 64.7% and the maximum abundance was 3.07 ± 0.25 × 10(8) copies/L (increased by five orders of magnitude) in the nitrite reactor. DAMO bacteria showed greater diversity in the nitrate reactor, and one was similar to M. oxyfera; DAMO bacteria in the nitrite reactor were relatively unified and similar to M. sinica. Interestingly, no DAMO archaea were found in the nitrate reactor. This study will improve the understanding of the impact of nitrogen source on DAMO and Anammox co-culture enrichment.

  6. Screening of lactic acid bacteria isolated from Serbian kajmak for use in starter cultures

    Directory of Open Access Journals (Sweden)

    Joković, N.

    2014-09-01

    Full Text Available One hundred and seventy eight isolates of lactic acid bacteria (LAB were isolated by pour plate and enrichment techniques from a sample of milk used for kajmak production and three samples of kajmak from one month ripening period. The identification of isolates was performed by phenotypic characterization followed by molecular identification using (GTG5-PCR and sequence analysis of 16S rRNA gene. Isolates belonged to Lactococcus lactis and Enterococcus faecium were found in milk and kajmak samples while Leuconostoc mesenteroides and Enterococcus durans were the most frequently isolated species from kajmak samples. Streptococcus thermophilus were isolated from milk sample only with enrichment technique. Further characterization of LAB isolates was done for technological properties which are important for industrial application of LAB. Strains of Lc. lactis and S. thermophilus that showed very good acidification and proteolityc activities and L. mesenteroides strains that metabolized citrate can be used in development of starter cultures for eventual industrial production of kajmak. Additionally, producers of antimicrobial compounds belonged to Lc. lactis subsp. lactis biovar. diacetylactis can be used for control of undesirable microflora in kajmak production.

  7. Inoculation of paperboard mill sludge versus mixed culture bacteria for hydrogen production from paperboard mill wastewater.

    Science.gov (United States)

    Farghaly, Ahmed; Tawfik, Ahmed; Danial, Amal

    2016-02-01

    A comparative evaluation of paperboard mill sludge (PMS) versus mixed culture bacteria (MCB) as inoculum for hydrogen production from paperboard mill wastewater (PMW) was investigated. The experiments were conducted at different initial cultivation pHs, inoculums to substrate ratios (ISRs gVS/gCOD), and hydraulic retention times (HRTs). The peak hydrogen yield (HY) of 5.29 ± 0.16 and 1.22 ± 0.11 mmol/gCODinitial was occurred at pH = 5 for MCB and PMS, respectively. At pH of 5, the HY and COD removal achieved the highest values of 2.26 ± 0.14 mmol/gCODinitial and 86 ± 1.6% at ISR = 6 for MCB, and 2.38 ± 0.25 mmol/gCODinitial and 60.4 ± 2.5% at ISRs = 3 for PMS. The maximum hydrogen production rate was 93.75 ± 8.9 mmol/day at HRT = 9.6 h from continuous upflow anaerobic reactor inoculated with MCB. Meanwhile, the 16S ribosomal RNA (rRNA) gene fragments indicated a dominance of a novel hydrogen-producing bacterium of Stenotrophomonas maltophilia for PMS microbial community. On the other hand, Escherichia fergusonii and Enterobacter hormaechei were the predominant species for MCB.

  8. The genetic diversity of culturable nitrogen-fixing bacteria in the rhizosphere of wheat.

    Science.gov (United States)

    Venieraki, Anastasia; Dimou, Maria; Pergalis, Panagiotis; Kefalogianni, Io; Chatzipavlidis, Iordanis; Katinakis, Panagiotis

    2011-02-01

    A total of 17 culturable nitrogen-fixing bacterial strains associated with the roots of wheat growing in different regions of Greece were isolated and characterized for plant-growth-promoting traits such as auxin production and phosphate solubilization. The phylogenetic position of the isolates was first assessed by the analysis of the PCR-amplified 16S rRNA gene. The comparative sequence analysis and phylogenetic analysis based on 16S rRNA gene sequences show that the isolates recovered in this study are grouped with Azospirillum brasilense, Azospirillum zeae, and Pseudomonas stutzeri. The diazotrophic nature of all isolates was confirmed by amplification of partial nifH gene sequences. The phylogenetic tree based on nifH gene sequences is consistent with 16S rRNA gene phylogeny. The isolates belonging to Azospirillum species were further characterized by examining the partial dnaK gene phylogenetic tree. Furthermore, it was demonstrated that the ipdC gene was present in all Azospirillum isolates, suggesting that auxin is mainly synthesized via the indole-3-pyruvate pathway. Although members of P. stutzeri and A. zeae are known diazotrophic bacteria, to the best of our knowledge, this is the first report of isolation and characterization of strains belonging to these bacterial genera associated with wheat.

  9. Populations of Select Cultured and Uncultured Bacteria in the Rumen of Sheep and the Effect of Diets and Ruminal Fractions

    Directory of Open Access Journals (Sweden)

    Jill Stiverson

    2011-01-01

    Full Text Available The objective of this study was to assess the importance of select cultured and uncultured bacteria in the rumen by quantifying their populations and the effect of diets and ruminal fractions. Full-length 16S rRNA gene (rrs sequences were recovered from rumen samples using specific primers designed from partial sequences recovered previously. Five uncultured bacterial operational taxonomic units (OTUs were quantified using specific quantitative PCR (qPCR in fractionated ruminal samples from sheep fed either hay alone or hay plus corn. Species Fibrobacter succinogenes, Ruminococcus albus, R. flavefaciens, Ruminobacter amylophilus, Selenomonas ruminantium, and Mitsuokella multacida and genera Butyrivibrio and Prevotella were also quantified as comparison. The full-length rrs sequence improved taxonomic assignments of partial rrs sequences. Genus Prevotella had the greatest abundance. Of the three major cultured cellulolytic species, R. flavefaciens was most abundant, followed by R. albus and F. succinogenes. The five uncultured bacterial OTUs, classified to genus Acetivibrio, genus Allobaculum, family Ruminococcaceae, order Clostridiales, or class Clostridia, had abundance comparable to that of the above species of genera except Prevotella. Corn supplementation and fractions affected distribution of the rumen bacteria, but to a limited extent. When compared to the qPCR data, sequence frequencies in the rrs clone libraries tended to overestimate the abundance of the bacteria represented. This study showed that abundance and population dynamics of uncultured bacteria can be quantified by specific qPCR, which complements the results of rrs clone libraries. This study also revealed that some uncultured bacteria might be as important as some of the well-characterized bacteria in the rumen. The approach used should be applicable to assess the abundance and potential importance of uncultured bacteria in other environments.

  10. Metagenomic Analysis Reveals Symbiotic Relationship among Bacteria in Microcystis-Dominated Community.

    Science.gov (United States)

    Xie, Meili; Ren, Minglei; Yang, Chen; Yi, Haisi; Li, Zhe; Li, Tao; Zhao, Jindong

    2016-01-01

    Microcystis bloom, a cyanobacterial mass occurrence often found in eutrophicated water bodies, is one of the most serious threats to freshwater ecosystems worldwide. In nature, Microcystis forms aggregates or colonies that contain heterotrophic bacteria. The Microcystis-bacteria colonies were persistent even when they were maintained in lab culture for a long period. The relationship between Microcystis and the associated bacteria was investigated by a metagenomic approach in this study. We developed a visualization-guided method of binning for genome assembly after total colony DNA sequencing. We found that the method was effective in grouping sequences and it did not require reference genome sequence. Individual genomes of the colony bacteria were obtained and they provided valuable insights into microbial community structures. Analysis of metabolic pathways based on these genomes revealed that while all heterotrophic bacteria were dependent upon Microcystis for carbon and energy, Vitamin B12 biosynthesis, which is required for growth by Microcystis, was accomplished in a cooperative fashion among the bacteria. Our analysis also suggests that individual bacteria in the colony community contributed a complete pathway for degradation of benzoate, which is inhibitory to the cyanobacterial growth, and its ecological implication for Microcystis bloom is discussed.

  11. Metagenomic analysis reveals symbiotic relationship among bacteria in Microcystis-dominated community

    Directory of Open Access Journals (Sweden)

    Meili eXie

    2016-02-01

    Full Text Available Microcystis bloom, a cyanobacterial mass occurrence often found in eutrophicated water bodies, is one of the most serious threats to freshwater ecosystems worldwide. In nature, Microcystis forms aggregates or colonies that contain heterotrophic bacteria. The Microcystis-bacteria colonies were persistent even when they were maintained in lab culture for a long period. The relationship between Microcystis and the associated bacteria was investigated by a metagenomic approach in this study. We developed a visualization-guided method of binning for genome assembly after total colony DNA sequencing. We found that the method was effective in grouping sequences and it did not require reference genome sequence. Individual genomes of the colony bacteria were obtained and they provided valuable insights into microbial community structures. Analysis of metabolic pathways based on these genomes revealed that while all heterotrophic bacteria were dependent upon Microcystis for carbon and energy, Vitamin B12 biosynthesis, which is required for growth by Microcystis, was accomplished in a cooperative fashion among the bacteria. Our analysis also suggests that individual bacteria in the colony community contributed a complete pathway for degradation of benzoate, which is inhibitory to the cyanobacterial growth, and its ecological implication for Microcystis bloom is discussed.

  12. Degradation of alkenones by aerobic heterotrophic bacteria: Selective or not ?

    Digital Repository Service at National Institute of Oceanography (India)

    Rontani, J-F.; Harji, R.; Guasco, S.; Prahl, F.G.; Volkman, J.K.; Bhosle, N.B.; Bonin, P.

    -treated algal cells. The observed increases in U sup (k’) sub(37) are equivalent to a +2 degrees C and +3.3 degrees C change in the inferred temperature. Our results clearly show that intense aerobic microbial degradative processes have the potential...

  13. Role of Heterotrophic Bacteria in Marine Ecological Processes

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaiah, N.

    are then developed into the fossil fuels and extracted as oil and gas to drive the world?s economy. The burning of fossil fuel releases large quantities of CO2 into the atmosphere, which may accumulate over time or can be incorporated into plant material... the natural sulphur cycle, rather drastically. The burning of fossil fuels burdens the air with excessive sulphur dioxide, which is washed out by rain into the soil and aquatic environments. Industrialization adds considerable amounts of sulphur dioxide...

  14. Genetic and metabolic variability in autotrophic and heterotrophic bacteria

    Science.gov (United States)

    Decicco, B. T.

    1972-01-01

    The studies to evaluate an organism's ability to maintain normal physiological activities over a long period of time in a bioregenerative system are presented. Studies reviewed include: heat tolerant mutants of Pseudomonas fluoresceins, virulence factors of the Staphylococci, and the effect of mutations on the virulence for man in common and ubiquitous microorganisms.

  15. Removal of crude petroleum hydrocarbons by heterotrophic bacteria ...

    African Journals Online (AJOL)

    SERVER

    2007-07-04

    Jul 4, 2007 ... 1Health Safety and Environment, Shell Petroleum Development Company Limited, P. O. Box 263, Old Aba ... Sufficient supply of nutrients and their influence on the .... their enduring presence in the Niger Delta ecosystems ..... Soil and Fresh Water Vegetation Union Graft Publs. ... The bacterial Community.

  16. Fish waste management by conversion into heterotrophic bacteria biomass

    NARCIS (Netherlands)

    Schneider, O.

    2006-01-01

    Just as all other types of animal production, aquaculture produces waste. This waste can be managed outside the production system, comparable to terrestrial husbandry systems. However, particularly recirculation aquaculture systems (RAS) are suited to manage waste within the system. In this case, pr

  17. Temporal variations in the abundance of heterotrophic bacteria in ...

    African Journals Online (AJOL)

    Administrator

    of fertilizers and pesticides in agricultural practices, landscape alteration ... Sewage and different solid and liquid wastes are released into the open canal, which is less ... processor controlled Conductivity meter, model 306. The instrument.

  18. Distribution of biomass of heterotrophic bacterioplankton in the Bohai Sea

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Distribution, variation and impact factors of biomass of bacterioplankton from April to May 1999in Bohai Sea were studied in DAPI method with epifluorescence microscopy. The biomass in surface waters showed a small day-night variation, varying from 0.13 to 2.51 μg/dm3 with an average of 0.84 μg/dm3. The biomass in bottom waters showed, however, a large variation, changing from 0.15 to 4.18 μg/dm3 with an average of 1.36 μg/dm3. The peak values occurred at 5 and 11 a.m. The bottom water biomass showed a significant correlation with particulate organic carbon (r=0.639, P<0.05). Heterotrophic bacterioplankton biomass was high in nearshore waters and low in offshore areas with a high biomass zone around Huanghe (Yellow) River mouth,showing the same distribution of nutrients. In vertical distribution, heterotrophic bacteria biomass in bottom waters was higher than that in surface water.

  19. Discrimination of Four Marine Biofilm-Forming Bacteria by LC-MS Metabolomics and Influence of Culture Parameters.

    Science.gov (United States)

    Favre, Laurie; Ortalo-Magné, Annick; Greff, Stéphane; Pérez, Thierry; Thomas, Olivier P; Martin, Jean-Charles; Culioli, Gérald

    2017-04-12

    Most marine bacteria can form biofilms, and they are the main components of biofilms observed on marine surfaces. Biofilms constitute a widespread life strategy, as growing in such structures offers many important biological benefits. The molecular compounds expressed in biofilms and, more generally, the metabolomes of marine bacteria remain poorly studied. In this context, a nontargeted LC-MS metabolomics approach of marine biofilm-forming bacterial strains was developed. Four marine bacteria, Persicivirga (Nonlabens) mediterranea TC4 and TC7, Pseudoalteromonas lipolytica TC8, and Shewanella sp. TC11, were used as model organisms. The main objective was to search for some strain-specific bacterial metabolites and to determine how culture parameters (culture medium, growth phase, and mode of culture) may affect the cellular metabolism of each strain and thus the global interstrain metabolic discrimination. LC-MS profiling and statistical partial least-squares discriminant analyses showed that the four strains could be differentiated at the species level whatever the medium, the growth phase, or the mode of culture (planktonic vs biofilm). A MS/MS molecular network was subsequently built and allowed the identification of putative bacterial biomarkers. TC8 was discriminated by a series of ornithine lipids, while the P. mediterranea strains produced hydroxylated ornithine and glycine lipids. Among the P. mediterranea strains, TC7 extracts were distinguished by the occurrence of diamine derivatives, such as putrescine amides.

  20. Antibiotic resistant bacteria/genes dissemination in lacustrine sediments highly increased following cultural eutrophication of Lake Geneva (Switzerland).

    Science.gov (United States)

    Thevenon, Florian; Adatte, Thierry; Wildi, Walter; Poté, John

    2012-02-01

    This study investigates faecal indicator bacteria (FIB), multiple antibiotic resistant (MAR), and antibiotic resistance genes (ARGs), of sediment profiles from different parts of Lake Geneva (Switzerland) over the last decades. MARs consist to expose culturable Escherichia coli (EC) and Enterococcus (ENT) to mixed five antibiotics including Ampicillin, Tetracycline, Amoxicillin, Chloramphenicol and Erythromycin. Culture-independent is performed to assess the distribution of ARGs responsible for, β-lactams (blaTEM; Amoxicillin/Ampicillin), Streptomycin/Spectinomycin (aadA), Tetracycline (tet) Chloramphenicol (cmlA) and Vancomycin (van). Bacterial cultures reveal that in the sediments deposited following eutrophication of Lake Geneva in the 1970s, the percentage of MARs to five antibiotics varied from 0.12% to 4.6% and 0.016% to 11.6% of total culturable EC and ENT, respectively. In these organic-rich bacteria-contaminated sediments, the blaTEM resistant of FIB varied from 22% to 48% and 16% to 37% for EC and ENT respectively, whereas the positive PCR assays responsible for tested ARGs were observed for EC, ENT, and total DNA from all samples. The aadA resistance gene was amplified for all the sediment samples, including those not influenced by WWTP effluent water. Our results demonstrate that bacteria MARs and ARGs highly increased in the sediments contaminated with WWTP effluent following the cultural eutrophication of Lake Geneva. Hence, the human-induced changing limnological conditions highly enhanced the sediment microbial activity, and therein the spreading of antibiotic resistant bacteria and genes in this aquatic environment used to supply drinking water in a highly populated area. Furthermore, the presence of the antibiotic resistance gene aadA in all the studied samples points out a regional dissemination of this emerging contaminant in freshwater sediments since at least the late nineteenth century.

  1. Biodegradation of ortho-Cresol by a Mixed Culture of Nitrate-Reducing Bacteria Growing On Toluene

    DEFF Research Database (Denmark)

    Flyvbjerg, John; Jørgensen, Claus; Arvin, Erik

    1993-01-01

    A mixed culture of nitrate-reducing bacteria degraded o-cresol in the presence of toluene as a primary growth substrate. No degradation of o-cresol was observed in the absence of toluene or when the culture grew on p-cresol and 2,4-dimethylphenol. In batch cultures, the degradation of o-cresol st......A mixed culture of nitrate-reducing bacteria degraded o-cresol in the presence of toluene as a primary growth substrate. No degradation of o-cresol was observed in the absence of toluene or when the culture grew on p-cresol and 2,4-dimethylphenol. In batch cultures, the degradation of o...... of unidentified water-soluble intermediates. A mathematical model based on a simplified Monod equation is used to describe the kinetics of o-cresol degradation. In this model, the biomass activity toward o-cresol is assumed to decay according to first-order kinetics once toluene is depleted. On the basis...

  2. Stochastic modelling of Listeria monocytogenes single cell growth in cottage cheese with mesophilic lactic acid bacteria from aroma producing cultures

    DEFF Research Database (Denmark)

    Østergaard, Nina Bjerre; Christiansen, Lasse Engbo; Dalgaard, Paw

    2015-01-01

    for pH, lactic acid concentration and initial concentration of lactic acid bacteria. These data and bootstrap sampling were used to represent product variability in the stochastic model. Lag time data were estimated from observed growth data (lactic acid bacteria) and from literature on L. monocytogenes...... single cells. These lag time data were expressed as relative lag times and included in growth models. A stochastic model was developed from an existing deterministic growth model including the effect of five environmental factors and inter-bacterial interaction [Østergaard, N.B, Eklöw, A and Dalgaard, P....... 2014. Modelling the effect of lactic acid bacteria from starter- and aroma culture on growth of Listeria monocytogenes in cottage cheese. International Journal of Food Microbiology. 188, 15-25]. Growth of L. monocytogenes single cells, using lag time distributions corresponding to three different...

  3. Identification of intracellular bacteria in adenoid and tonsil tissue specimens: the efficiency of culture versus fluorescent in situ hybridization (FISH).

    Science.gov (United States)

    Stępińska, M; Olszewska-Sosińska, O; Lau-Dworak, M; Zielnik-Jurkiewicz, B; Trafny, E A

    2014-01-01

    Monocyte/macrophage cells from human nasopharyngeal lymphoid tissue can be a source of bacteria responsible for human chronic and recurrent upper respiratory tract infection. Detection and characterization of pathogens surviving intracellularly could be a key element in bacteriological diagnosis of the infections as well as in the study on interactions between bacteria and their host. The present study was undertaken to assess the possibility of isolation of viable bacteria from the cells expressing monocyte/macrophage marker CD14 in nasopharyngeal lymphoid tissue. Overall, 74 adenotonsillectomy specimens (adenoids and tonsils) from 37 children with adenoid hypertrophy and recurrent infections as well as 15 specimens from nine children with adenoid hypertrophy, which do not suffer from upper respiratory tract infections (the control group), were studied. The suitability of immunomagnetic separation for extraction of CD14(+) cells from lymphoid tissue and for further isolation of the intracellular pathogens has been shown. The coexistence of living pathogens including Haemophilus influenzae, Staphylococcus aureus, and Streptococcus pyogenes with the bacteria representing normal nasopharyngeal microbiota inside CD14(+) cells was demonstrated. Twenty-four strains of these pathogens from 32.4 % of the lysates of CD14(+) cells were isolated. Concurrently, the fluorescent in situ hybridization (FISH) with a universal EUB388, and the species-specific probes demonstrated twice more often the persistence of these bacterial species in the lysates of CD14(+) cells than conventional culture. Although the FISH technique appears to be more sensitive than traditional culture in the intracellular bacteria identification, the doubts on whether the bacteria are alive, and therefore, pathogenic would still exist without the strain cultivation.

  4. Efficiency of some soil bacteria for chemical oxygen demand reduction of synthetic chlorsulfuron solutions under agiated culture conditions.

    Science.gov (United States)

    Erguven, G O; Yildirim, N

    2016-05-30

    This study searches the efficiency of certain soil bacteria on chemical oxygen demand (COD) reduction of synthetic chlorsulfuron solutions under agitated culture conditions. It also aims to determine the turbidity of liquid culture medium with chlorsulfuron during bacterial incubation for 120 hours. As a result the highest and lowest COD removal efficiency of bacteria was determined for Bacillus simplex as 94% and for Micrococcus luteus as 70%, respectively at the end of the 96th hour. It was found that COD removal efficiency showed certain differences depend on the bacterial species. It was also observed that B. simplex had the highest COD removal efficiency and it was a suitable bacterium species for bioremediation of a chlorsulfuron contaminated soils.

  5. Effect of Physical and Chemical Changes on the Antimicrobial Activity of Culture Supernatant Fluid of Lactic Acid Bacteria

    Directory of Open Access Journals (Sweden)

    Leila Goudarzi (MSc

    2016-04-01

    Full Text Available Background and Objective: Lactic acid bacteria are Gram-positive, catalase-negative, nonsporulating, either rod- or coccus-shaped bacteria that have beneficial effects on their hosts by producing antimicrobial substances such as lactic acid, hydrogen peroxide, bacteriocins and biosurfactants. Bacteriocins are antimicrobial peptides that are produced by bacteria and can inhibit the growth of other bacteria. Methods: In this experimental study, bacteriocin production by Lactobacilli as known probiotic strains was evaluated in different physicochemical conditions. Antagonistic activity was evaluated using quantitative method of Microscale Optical Density Assay (MODA. After neutralization of acid and treatment with various enzymes, temperature, pH and NaCl conditions, the antimicrobial activity of culture supernatant fluid of Lactobacillus acidophilus and L. plantarum was investigated against pathogenic Proteus. Results: The culture supernatant fluid of Lactobacilli was sensitive to proteolytic enzymes with relatively good stability to temperature. The antimicrobial activity was also present due to production of bacteriocin under different NaCl conditions (1 to 4% NaCl and pH range of 5 to 8. Conclusion: It seems that the antimicrobial liquid of Lactobacillus strains contains bacteriocin, which shows antimicrobial effects against pathogenic strains of Proteus. To investigate further this effect, some complementary studies should be performed.

  6. Comparison of two commercial broadrange PCR and sequencing assays for identification of bacteria in culture-negative clinical samples

    DEFF Research Database (Denmark)

    Stavnsbjerg, Camilla; Frimodt-Moller, Niels; Moser, Claus Ernst

    2017-01-01

    Background Culturing has long been the gold standard for detecting aetiologic agents in bacterial infections. In some cases, however, culturing fails to detect the infection. To further investigate culture-negative samples, amplification and subsequent sequencing of the 16S rRNA gene is often...... applied. The aim of the present study was to compare the current method used at our Department of Clinical Microbiology, based on the MicroSeq ID system (Applied Biosystems, USA) with the Universal Microbe Detection (UMD) SelectNA kit (Molzym, Germany). Methods 76 culture-negative samples were first...... in a real-time PCR and sequenced. Results 22 of 76 samples (28.9%) were positive for bacteria with the UMD SelectNA, which was significantly more (p = 0.0055) than the MicroSeq ID where 11 of 76 samples (14.5%) were positive. The UMD SelectNA assay identified more relevant bacterial pathogens than the Micro...

  7. Isolation and phylogenetic analysis of heterotrophic nitrobacteria

    Institute of Scientific and Technical Information of China (English)

    SU Jun-feng; MA Fang; GUO Jing-bo; HOU Ning; GAO Shan-shan; WANG Hong-yu

    2008-01-01

    A method about the isolation of heterotrophic nitrosebactria and the characteristics of heterotrophic nitrosobaetria were studied, it can be seen from the fluorescence in situ hybridization results of the bio-mem-brahe sample from the bio-ceramic reactor, the spots of green nitrosobacteria are obviously more than those of orange nitrohaeteria. Two heterotrophic nitrohacteria were isolated from the bio-ceramic reactor. By sequencing 16SrDNA and establishing the phylogenic tree, they were identified physiologically and biochemically as Pseudomonas sp.. After 12 d, the COD removal efficiency of wgy55 and wgy68 were 45.03% and 50.85% , the NH4-N removal efficiency of them were 80.12% and 85.93%, and the TN removal efficiency of them were 69.71% and 64.7%. The final concentration of NO2-N of wgy55 and wgy68 was 0.753 mg/L and 0.601 mg/ L, and that of NO3-N was 3.21 mg/L and 3.38 mg/L. These results show that wgy55 and wgy68 have the ca-pability of nitrification and they are heterotrophic nitrobacteria.

  8. Miniaturized extinction culturing is the preferred strategy for rapid isolation of fast-growing methane-oxidizing bacteria

    OpenAIRE

    Hoefman, Sven; van der Ha, David; De Vos, Paul; Boon, Nico; Heylen, Kim

    2012-01-01

    Summary Methane‐oxidizing bacteria (MOB) have a large potential as a microbial sink for the greenhouse gas methane as well as for biotechnological purposes. However, their application in biotechnology has so far been hampered, in part due to the relative slow growth rate of the available strains. To enable the availability of novel strains, this study compares the isolation of MOB by conventional dilution plating with miniaturized extinction culturing, both performed after an initial enrichme...

  9. Effects of Bacillus subtilis natto and Different Components in Culture on Rumen Fermentation and Rumen Functional Bacteria In Vitro.

    Science.gov (United States)

    Sun, Peng; Li, Jinan; Bu, Dengpan; Nan, Xuemei; Du, Hong

    2016-05-01

    This study was to investigate the effects of live or autoclaved Bacillus subtilis natto, their fermented products and media on rumen fermentation and rumen functional bacteria in vitro. Rumen fluid from three multiparous lactating Holstein cows was combined and transferred into serum bottles after diluted. Fifteen serum bottles were divided into five treatments, which were designed as following: CTR (the fermentation of 0.5 g TMR and ruminal fluids from dairy cows), LBS (CTR plus a minimum of 10(11) cfu live Bacillus subtilis natto), ABS (CTR plus a minimum of 10(11) cfu autoclaved Bacillus subtilis natto), BSC (CTR plus 1 ml Bacillus subtilis natto fermentation products without bacteria), and BSM (CTR plus 1 ml liquid fermentation medium). When separated from the culture, live Bacillus subtilis natto individually increased the concentrations of ammonia-N (P Bacillus subtilis natto has the similar function with the live bacteria except for the ratio of acetate and propionate. Except B. fibrisolvens, live or autoclaved Bacillus subtilis natto did not influence or decreased the 16S rRNA gene quantification of the detected bacteria. BSC and BSM altered the relative expression of certain functional bacteria in the rumen. These results indicated that it was Bacillus subtilis natto thalli that played the important role in promoting rumen fermentation when applied as a probiotic in dairy ration.

  10. The microbial spectrum of neonatal sepsis in Uganda: recovery of culturable bacteria in mother-infant pairs.

    Science.gov (United States)

    Kiwanuka, Julius; Bazira, Joel; Mwanga, Juliet; Tumusiime, Dickson; Nyesigire, Eunice; Lwanga, Nkangi; Warf, Benjamin C; Kapur, Vivek; Poss, Mary; Schiff, Steven J

    2013-01-01

    Neonatal sepsis in the developing world is incompletely characterized. We seek to characterize the microbial spectrum involved in sepsis and determine the role of maternal transmission by comparing organisms that can be cultured from septic newborn infants and their mothers. From 80 consecutive mother-infant pairs meeting clinical criteria for neonatal sepsis, we collected infant blood and spinal fluid, and maternal blood and vaginal specimens. Identifiable bacteria were recovered from the blood in 32.5% of infants, and from 2.5% of cerebrospinal fluid cultures, for a total of 35% recoverable putative causative agents. Bacteria recovered from vaginal specimens were not concordant with those recovered from infants. Similarly there was no concordance of bacteria recovered from blood and cerebrospinal fluid. We conclude that relying on traditional bacterial culture techniques does not adequately delineate the role of maternal versus environmental sources of neonatal sepsis in this setting. More sensitive molecular approaches will be needed to properly characterize the maternal and environmental microbial community involved in neonatal sepsis in such developing countries.

  11. 16S rRNA Gene Phylogenesis of Culturable Predominant Bacteria from Diseased Apostichopus japonicus(Holothuroidea, Echinodermata)

    Institute of Scientific and Technical Information of China (English)

    MA Haiyan; JIANG Guoliang; WU Zhiqiang; WANG Xin

    2009-01-01

    Cultured Apostichopusjaponicus in China suffers from a kind of skin ulceration disease that has caused severe economic loss in recent years. The disease, pathogens of which are supposed to be bacteria by most researchers, is highly infectious and can often cause all individuals in the same culture pool to die in a very short time. The 16S rRNA gene phylogenesis of the culturable bacteria from the lesions of diseased individuals was conducted to study the biodiversity of the bacterial communities in the lesions and to identify probable pathogen(s) associated with this kind of disease. S. japonica samples were selected from a hatchery located in the eastern part of Qingdao, China. Bacterial universal primers GM5F and DS907R were used to amplify the 16S rRNA gene of bacteria colonies, and touchdown PCR was performed to amplify the target sequences. The results suggest that γ- proteobacteria (Alteromonadales and Vibrionales) of CFB group, many strains of which have been also determined as pathogens in other marine species, are the predominant bacterial genera of the diseased Apostichopusjaponicus individuals.

  12. Food waste as nutrient source in heterotrophic microalgae cultivation.

    Science.gov (United States)

    Pleissner, Daniel; Lam, Wan Chi; Sun, Zheng; Lin, Carol Sze Ki

    2013-06-01

    Glucose, free amino nitrogen (FAN), and phosphate were recovered from food waste by fungal hydrolysis using Aspergillus awamori and Aspergillus oryzae. Using 100g food waste (dry weight), 31.9 g glucose, 0.28 g FAN, and 0.38 g phosphate were recovered after 24h of hydrolysis. The pure hydrolysate has then been used as culture medium and nutrient source for the two heterotrophic microalgae Schizochytrium mangrovei and Chlorella pyrenoidosa, S. mangrovei and C. pyrenoidosa grew well on the complex food waste hydrolysate by utilizing the nutrients recovered. At the end of fermentation 10-20 g biomass were produced rich in carbohydrates, lipids, proteins, and saturated and polyunsaturated fatty acids. Results of this study revealed the potential of food waste hydrolysate as culture medium and nutrient source in microalgae cultivation.

  13. Rapid identification of bacteria from positive blood culture bottles by MALDI-TOF MS following short-term incubation on solid media.

    Science.gov (United States)

    Altun, Osman; Botero-Kleiven, Silvia; Carlsson, Sarah; Ullberg, Måns; Özenci, Volkan

    2015-11-01

    Rapid identification of bacteria from blood cultures enables early initiation of appropriate antibiotic treatment in patients with bloodstream infections (BSI). The objective of the present study was to evaluate the use of matrix-associated laser desorption ionization-time of flight (MALDI-TOF) MS after a short incubation on solid media for rapid identification of bacteria from positive blood culture bottles. MALDI-TOF MS was performed after 2.5 and 5.5 h plate incubation of samples from positive blood cultures. Identification scores with values ≥ 1.7 were accepted as successful identification if the results were confirmed by conventional methods. Conventional methods included MALDI-TOF MS, Vitek 2, and diverse biochemical and agglutination tests after overnight culture. In total, 515 positive blood cultures with monomicrobial bacterial growth representing one blood culture per patient were included in the study. There were 229/515 (44.5%) and 286/515 (55.5%) blood culture bottles with Gram-negative bacteria (GNB) and Gram-positive bacteria (GPB), respectively. MALDI-TOF MS following short-term culture could accurately identify 300/515 (58.3%) isolates at 2.5 h, GNB being identified in greater proportion (180/229; 78.6%) than GPB (120/286; 42.0%). In an additional 124/515 bottles (24.1%), identification was successful at 5.5 h, leading to accurate identification of bacteria from 424/515 (82.3%) blood cultures after short-term culture. Interestingly, 11/24 of the isolated anaerobic bacteria could be identified after 5.5 h. The present study demonstrates, in a large number of clinical samples, that MALDI-TOF MS following short-term culture on solid medium is a reliable and rapid method for identification of bacteria from blood culture bottles with monomicrobial bacterial growth.

  14. Changes in diversity of cultured bacteria resistant to erythromycin and tetracycline in swine manure during simulated composting and lagoon storage.

    Science.gov (United States)

    Wang, L; Gutek, A; Grewal, S; Michel, F C; Yu, Z

    2015-09-01

    This study investigated the impact of composting and lagoon storage on survival and change in diversity of tetracycline-resistant (Tc(r) ) and erythromycin-resistant (Em(r) ) bacteria and the resistance genes they carry in swine manure. Treatments were arranged as a 2 × 2 factorial design: composting vs lagoon storage and 0 vs 1% Surround WP Crop Protectant (a clay product) in three replicates. After 48 days of treatments, resistant bacteria were enumerated by selective plating and identified by 16S rRNA gene sequencing. The erm and the tet gene(s) carried by the resistant isolates were screened using class-specific PCR assays. The plate counts of Tc(r) and Em(r) bacteria decreased by 4-7 logs by composting, but only by 1-2 logs by the lagoon treatment. During the treatments, Acinetobacter gave way to Pseudomonas and Providencia as the largest resistant genera. The clay product had little effect on survival or diversity of resistant bacteria. Of six classes of erm and seven classes of tet genes tested, changes in prevalence were also noted. The results indicate that composting can dramatically shift Tc(r) and Em(r) bacterial populations, and composting can be an effective and practical approach to decrease dissemination of antibiotic resistance from swine farms to the environment. The presented research provided evidence that composting is much more effective than lagoon storage in dramatically decreasing culturable bacteria resistant to erythromycin and tetracycline in swine manure. Considerable diversity changes of resistant bacteria were also demonstrated during composting or lagoon storage. Overall, Acinetobacter was the major resistant genus in untreated swine manure, but pseudomonads and Providencia became the major resistant genera after the treatments. This is the first study that investigated diversity changes of cultured bacteria resistant to these two antibiotics during composting and lagoon storage of swine manure. New genes encoding resistance to

  15. Ubiquity and diversity of heterotrophic bacterial nasA genes in diverse marine environments.

    Directory of Open Access Journals (Sweden)

    Xuexia Jiang

    Full Text Available Nitrate uptake by heterotrophic bacteria plays an important role in marine N cycling. However, few studies have investigated the diversity of environmental nitrate assimilating bacteria (NAB. In this study, the diversity and biogeographical distribution of NAB in several global oceans and particularly in the western Pacific marginal seas were investigated using both cultivation and culture-independent molecular approaches. Phylogenetic analyses based on 16S rRNA and nasA (encoding the large subunit of the assimilatory nitrate reductase gene sequences indicated that the cultivable NAB in South China Sea belonged to the α-Proteobacteria, γ-Proteobacteria and CFB (Cytophaga-Flavobacteria-Bacteroides bacterial groups. In all the environmental samples of the present study, α-Proteobacteria, γ-Proteobacteria and Bacteroidetes were found to be the dominant nasA-harboring bacteria. Almost all of the α-Proteobacteria OTUs were classified into three Roseobacter-like groups (I to III. Clone library analysis revealed previously underestimated nasA diversity; e.g. the nasA gene sequences affiliated with β-Proteobacteria, ε-Proteobacteria and Lentisphaerae were observed in the field investigation for the first time, to the best of our knowledge. The geographical and vertical distributions of seawater nasA-harboring bacteria indicated that NAB were highly diverse and ubiquitously distributed in the studied marginal seas and world oceans. Niche adaptation and separation and/or limited dispersal might mediate the NAB composition and community structure in different water bodies. In the shallow-water Kueishantao hydrothermal vent environment, chemolithoautotrophic sulfur-oxidizing bacteria were the primary NAB, indicating a unique nitrate-assimilating community in this extreme environment. In the coastal water of the East China Sea, the relative abundance of Alteromonas and Roseobacter-like nasA gene sequences responded closely to algal blooms, indicating

  16. Ubiquity and diversity of heterotrophic bacterial nasA genes in diverse marine environments.

    Science.gov (United States)

    Jiang, Xuexia; Dang, Hongyue; Jiao, Nianzhi

    2015-01-01

    Nitrate uptake by heterotrophic bacteria plays an important role in marine N cycling. However, few studies have investigated the diversity of environmental nitrate assimilating bacteria (NAB). In this study, the diversity and biogeographical distribution of NAB in several global oceans and particularly in the western Pacific marginal seas were investigated using both cultivation and culture-independent molecular approaches. Phylogenetic analyses based on 16S rRNA and nasA (encoding the large subunit of the assimilatory nitrate reductase) gene sequences indicated that the cultivable NAB in South China Sea belonged to the α-Proteobacteria, γ-Proteobacteria and CFB (Cytophaga-Flavobacteria-Bacteroides) bacterial groups. In all the environmental samples of the present study, α-Proteobacteria, γ-Proteobacteria and Bacteroidetes were found to be the dominant nasA-harboring bacteria. Almost all of the α-Proteobacteria OTUs were classified into three Roseobacter-like groups (I to III). Clone library analysis revealed previously underestimated nasA diversity; e.g. the nasA gene sequences affiliated with β-Proteobacteria, ε-Proteobacteria and Lentisphaerae were observed in the field investigation for the first time, to the best of our knowledge. The geographical and vertical distributions of seawater nasA-harboring bacteria indicated that NAB were highly diverse and ubiquitously distributed in the studied marginal seas and world oceans. Niche adaptation and separation and/or limited dispersal might mediate the NAB composition and community structure in different water bodies. In the shallow-water Kueishantao hydrothermal vent environment, chemolithoautotrophic sulfur-oxidizing bacteria were the primary NAB, indicating a unique nitrate-assimilating community in this extreme environment. In the coastal water of the East China Sea, the relative abundance of Alteromonas and Roseobacter-like nasA gene sequences responded closely to algal blooms, indicating that NAB may be

  17. Clinical evaluation of the FilmArray blood culture identification panel in identification of bacteria and yeasts from positive blood culture bottles.

    Science.gov (United States)

    Altun, Osman; Almuhayawi, Mohammed; Ullberg, Måns; Ozenci, Volkan

    2013-12-01

    The FilmArray platform (FA; BioFire, Salt Lake City, UT) is a closed diagnostic system allowing high-order multiplex PCR analysis with automated readout of results directly from positive blood cultures in 1 h. In the present study, we evaluated the clinical performance of the FilmArray blood culture identification (BCID) panel, which includes 19 bacteria, five yeasts, and three antibiotic resistance genes. In total, 206 blood culture bottles were included in the study. The FilmArray could identify microorganisms in 153/167 (91.6%) samples with monomicrobial growth. Thirteen of the 167 (7.8%) microorganisms were not covered by the FilmArray BCID panel. In 6/167 (3.6%) samples, the FilmArray detected an additional microorganism compared to blood culture. When polymicrobial growth was analyzed, the FilmArray could detect all target microorganisms in 17/24 (71%) samples. Twelve blood culture bottles that yielded a positive signal but showed no growth were also negative by FilmArray. In 3/206 (1.5%) bottles, the FilmArray results were invalid. The results of the FilmArray were reproducible, as demonstrated by the testing and retesting of five bottles in the same day and a longitudinal follow-up of five other blood cultures up to 4 weeks. The present study shows that the FilmArray is a rapid identification method with high performance in direct identification of bacteria and yeasts from positive blood culture bottles.

  18. Persistence and Potential Viable but Non-culturable State of Pathogenic Bacteria during Storage of Digestates from Agricultural Biogas Plants

    Science.gov (United States)

    Maynaud, Geraldine; Pourcher, Anne-Marie; Ziebal, Christine; Cuny, Anais; Druilhe, Céline; Steyer, Jean-Philippe; Wéry, Nathalie

    2016-01-01

    Despite the development of on-farm anaerobic digestion as a process for making profitable use of animal by-products, factors leading to the inactivation of pathogenic bacteria during storage of digestates remain poorly described. Here, a microcosm approach was used to evaluate the persistence of three pathogenic bacteria (Salmonella enterica Derby, Campylobacter coli and Listeria monocytogenes) in digestates from farms, stored for later land spreading. Nine samples, including raw digestates, liquid fractions of digestate and composted digestates, were inoculated with each pathogen and maintained for 40 days at 24°C. Concentrations of pathogens were monitored using culture and qPCR methods. The persistence of L. monocytogenes, detected up to 20 days after inoculation, was higher than that of Salmonella Derby, detected for 7–20 days, and of C. coli (not detected after 7 days). In some digestates, the concentration of the pathogens by qPCR assay was several orders of magnitude higher than the concentration of culturable cells, suggesting a potential loss of culturability and induction of Viable but Non-Culturable (VBNC) state. The potential VBNC state which was generally not observed in the same digestate for the three pathogens, occurred more frequently for C. coli and L. monocytogenes than for Salmonella Derby. Composting a digestate reduced the persistence of seeded L. monocytogenes but promoted the maintenance of Salmonella Derby. The effect of NH4+/NH3 on the culturability of C. coli and Salmonella Derby was also shown. The loss of culturability may be the underlying mechanism for the regrowth of pathogens. We have also demonstrated the importance of using molecular tools to monitor pathogens in environmental samples since culture methods may underestimate cell concentration. Our results underline the importance of considering VBNC cells when evaluating the sanitary effect of an anaerobic digestion process and the persistence of pathogens during the storage of

  19. Persistence and potential Viable but Non-culturable state of pathogenic bacteria during storage of digestates from agricultural biogas plants

    Directory of Open Access Journals (Sweden)

    Geraldine Maynaud

    2016-09-01

    Full Text Available Despite the development of on-farm anaerobic digestion as a process for making profitable use of animal by-products, factors leading to the inactivation of pathogenic bacteria during storage of digestates remain poorly described. Here, a microcosm approach was used to evaluate the persistence of three pathogenic bacteria (Salmonella enterica Derby, Campylobacter coli and Listeria monocytogenes in digestates from farms, stored for later land spreading. Nine samples, including raw digestates, liquid fractions of digestate and composted digestates, were inoculated with each pathogen and maintained for 40 days at 24°C. Concentrations of pathogens were monitored using culture and qPCR methods. The persistence of L. monocytogenes, detected up to 20 days after inoculation, was higher than that of Salmonella Derby, detected for 7-20 days, and of C. coli (not detected after 7 days. In some digestates, the concentration of the pathogens by qPCR assay was several orders of magnitude higher than the concentration of culturable cells, suggesting a potential loss of culturability and induction of Viable but Non-Culturable (VBNC state. The potential VBNC state which was generally not observed in the same digestate for the three pathogens, occurred more frequently for C. coli and L. monocytogenes than for Salmonella Derby. Composting a digestate reduced the persistence of seeded L. monocytogenes but promoted the maintenance of Salmonella Derby. The effect of NH4+/NH3 on the culturability of C. coli and Salmonella Derby was also shown.The loss of culturability may be the underlying mechanism for the regrowth of pathogens. We have also demonstrated the importance of using molecular tools to monitor pathogens in environmental samples since culture methods may underestimate cell concentration. Our results underline the importance of considering VBNC cells when evaluating the sanitary effect of an anaerobic digestion process and the persistence of pathogens during

  20. Phaeobacter inhibens as Probiotic Bacteria in Non-Axenic Artemia and Algae Cultures

    DEFF Research Database (Denmark)

    Grotkjær, Torben; D'Alvise, Paul; Bentzon-Tilia, Mikkel;

    2015-01-01

    Bacterial diseases are a major constraint in aquaculture, especially in larviculture. Antibiotics that can control pathogens should be avoided due to risk of antibiotic resistance. We have shown in axenic systems of live larval feed that marine Roseobacter clade bacteria can antagonize fish patho...... demonstrates that probiotic bacteria can be introduced at the stage of live feed and have a pathogen reducing effect in both an Artemia and a D. tertiolecta challenge setup. This can potentially limit the subsequent use of antibiotics for control of pathogenic bacteria....

  1. Stochastic modelling of Listeria monocytogenes single cell growth in cottage cheese with mesophilic lactic acid bacteria from aroma producing cultures.

    Science.gov (United States)

    Østergaard, Nina Bjerre; Christiansen, Lasse Engbo; Dalgaard, Paw

    2015-07-02

    A stochastic model was developed for simultaneous growth of low numbers of Listeria monocytogenes and populations of lactic acid bacteria from the aroma producing cultures applied in cottage cheese. During more than two years, different batches of cottage cheese with aroma culture were analysed for pH, lactic acid concentration and initial concentration of lactic acid bacteria. These data and bootstrap sampling were used to represent product variability in the stochastic model. Lag time data were estimated from observed growth data (lactic acid bacteria) and from literature on L. monocytogenes single cells. These lag time data were expressed as relative lag times and included in growth models. A stochastic model was developed from an existing deterministic growth model including the effect of five environmental factors and inter-bacterial interaction [Østergaard, N.B, Eklöw, A and Dalgaard, P. 2014. Modelling the effect of lactic acid bacteria from starter- and aroma culture on growth of Listeria monocytogenes in cottage cheese. International Journal of Food Microbiology. 188, 15-25]. Growth of L. monocytogenes single cells, using lag time distributions corresponding to three different stress levels, was simulated. The simulated growth was subsequently compared to growth of low concentrations (0.4-1.0 CFU/g) of L. monocytogenes in cottage cheese, exposed to similar stresses, and in general a good agreement was observed. In addition, growth simulations were performed using population relative lag time distributions for L. monocytogenes as reported in literature. Comparably good predictions were obtained as for the simulations performed using lag time data for individual cells of L. monocytogenes. Therefore, when lag time data for individual cells are not available, it was suggested that relative lag time distributions for L. monocytogenes can be used as a qualified default assumption when simulating growth of low concentrations of L. monocytogenes.

  2. Lack of detection of ampicillin resistance gene transfer from Bt176 transgenic corn to culturable bacteria under field conditions.

    Science.gov (United States)

    Badosa, Esther; Moreno, Carmen; Montesinos, Emilio

    2004-05-01

    Population levels of total and ampicillin-resistant culturable bacteria and the putative horizontal bla gene acquirement from Bt-corn were studied in commercial fields of transgenic corn in Spain during the years 2000-2003. Commercial fields consisting of conventional corn (Dracma) and Bt176 transgenic corn (Compa CB) were located in three climatic regions. The effect of corn type, plant material, field location, stage of sampling and year of study were studied on total and ampicillin resistant bacterial population levels, on median effective dose and on the slope of the dose-response curve to ampicillin. None of the parameters measured were significantly different (Ptransgenic and non-transgenic cornfields under the diverse conditions studied. However, in population levels of ampicillin resistant bacteria, the minimum difference between sample means to be significant with a likelihood of 80% was 8.9%. Specific detection of putative bacteria harbouring bla TEM-1 ampicillin resistance genes acquired from Bt176 corn was performed with a method based on the extraction of DNA from the culturable bacterial fraction and with PCR. Primers for PCR were targeted to the bla gene and the corresponding flanking regions present in the pUC18 cloning vector or the Bt176 construct. The culturable bacterial fraction of 144 field samples (up to 864 analysis, including ampicillin enrichments) was analysed by PCR. The estimated total number of bacteria analysed was 10(8). The level of detection of a transfer event according to the sensitivity of the methods used was 10(-6). Four samples of transgenic and five of non-transgenic corn gave positive signals. However, the amplification products did not correspond to the ones expected from Bt176 or pUC18. The limitations of the sampling design and of the methods used are discussed.

  3. Kinetic analysis of strains of lactic acid bacteria and acetic acid bacteria in cocoa pulp simulation media toward development of a starter culture for cocoa bean fermentation.

    Science.gov (United States)

    Lefeber, Timothy; Janssens, Maarten; Camu, Nicholas; De Vuyst, Luc

    2010-12-01

    The composition of cocoa pulp simulation media (PSM) was optimized with species-specific strains of lactic acid bacteria (PSM-LAB) and acetic acid bacteria (PSM-AAB). Also, laboratory fermentations were carried out in PSM to investigate growth and metabolite production of strains of Lactobacillus plantarum and Lactobacillus fermentum and of Acetobacter pasteurianus isolated from Ghanaian cocoa bean heap fermentations, in view of the development of a defined starter culture. In a first step, a selection of strains was made out of a pool of strains of these LAB and AAB species, obtained from previous studies, based on their fermentation kinetics in PSM. Also, various concentrations of citric acid in the presence of glucose and/or fructose (PSM-LAB) and of lactic acid in the presence of ethanol (PSM-AAB) were tested. These data could explain the competitiveness of particular cocoa-specific strains, namely, L. plantarum 80 (homolactic and acid tolerant), L. fermentum 222 (heterolactic, citric acid fermenting, mannitol producing, and less acid tolerant), and A. pasteurianus 386B (ethanol and lactic acid oxidizing, acetic acid overoxidizing, acid tolerant, and moderately heat tolerant), during the natural cocoa bean fermentation process. For instance, it turned out that the capacity to use citric acid, which was exhibited by L. fermentum 222, is of the utmost importance. Also, the formation of mannitol was dependent not only on the LAB strain but also on environmental conditions. A mixture of L. plantarum 80, L. fermentum 222, and A. pasteurianus 386B can now be considered a mixed-strain starter culture for better controlled and more reliable cocoa bean fermentation processes.

  4. How long can culturable bacteria and total DNA persist in environmental waters? The role of sunlight and solid particles.

    Science.gov (United States)

    Gutiérrez-Cacciabue, Dolores; Cid, Alicia G; Rajal, Verónica B

    2016-01-01

    In this work, sunlight inactivation of two indicator bacteria in freshwater, with and without solid particles, was studied and the persistence of culturable cells and total DNA was compared. Environmental water was used to prepare two matrices, with and without solid particles, which were spiked with Escherichia coli and Enterococcus faecalis. These matrices were used to prepare microcosm bags that were placed in two containers: one exposed to sunlight and the other in the dark. During one month, samples were removed from each container and detection was done by membrane filter technique and real-time PCR. Kinetic parameters were calculated to assess sunlight effect. Indicator bacteria without solid particles exposed to sunlight suffered an immediate decay (solid particles varied depending on the situation analyzed (T99 from 3 up to 60days), being always culturable E. coli more persistent than E. faecalis. On the other side, E. faecalis DNA persisted much longer than culturable cells (T99>40h in the dark with particles). In this case active cells were more prone to sunlight than total DNA and the protective effect of solid particles was also observed. Results highlight that the effects caused by the parameters which describe the behavior of culturable microorganisms and total DNA in water are different and must be included in simulation models but without forgetting that these parameters will also depend on bacterial properties, sensitizers, composition, type, and uses of the aquatic environment under assessment.

  5. Nondairy beverage produced by controlled fermentation with potential probiotic starter cultures of lactic acid bacteria and yeast.

    Science.gov (United States)

    Freire, Ana Luiza; Ramos, Cintia Lacerda; da Costa Souza, Patrícia Nirlane; Cardoso, Mauro Guilherme Barros; Schwan, Rosane Freitas

    2017-02-21

    This work aimed to develop a nondairy fermented beverage from a blend of cassava and rice based on Brazilian indigenous beverage cauim using probiotic lactic acid bacteria (LAB) and yeast. The indigenous strains Lactobacillus plantarum CCMA 0743 (from cauim) and Torulaspora delbrueckii CCMA 0235 (from tarubá), and the commercial probiotic, L. acidophilus LAC-04, were used as starter cultures in single and co-cultivations. The bacteria populations were around 8.0 log (CFU/mL) at the end of all fermentations as recommended for probiotic products. Higher residual starch contents were noted in the single LAB cultures (10.6% [w/w]) than in co-cultures (1.6g/L) and ethanol was lower than 0.5% (w/v) consisting in a non-alcoholic beverage. The assays containing yeast showed the highest antioxidant activity (around 10% by DPPH and ABTS methods). Therefore, a nondairy fermented beverage was successfully obtained, and the co-culture of LAB and T. delbrueckii could increase the product's functional properties.

  6. Enzymatic catalysis of mercury methylation by planktonic and biofilm cultures of sulfate- reducing bacteria

    Science.gov (United States)

    Lin, C.; Kampalath, R.; Jay, J.

    2007-12-01

    While biofilms are now known to be the predominant form of microbial growth in nature, little is known about their role in environmental mercury (Hg) methylation. Due to its long-range atmospheric transport, Hg contamination of food chains is a worldwide problem, impacting even pristine areas. Among different forms of mercury species, methylmercury (MeHg) is an extremely neurotoxic and biomagnification-prone compound that can lead to severely adverse health effects on wildlife and humans. Considerable studies have shown that in the aquatic environment the external supply of MeHg is not sufficient to account for MeHg accumulation in biota and in situ biological MeHg formation plays a critical role in determining the amount of MeHg in food webs; moreover, sulfate-reducing bacteria (SRB) has been identified as the principal Hg-methylating organisms in nature. In a wide range of aquatic systems wetlands are considered important sites for Hg methylation mostly because of the environmental factors that promote microbial activity within, and biofilms are especially important in wetland ecosystems due to large amount of submerged surfaces. Although recent work has focused on the environmental factors that control MeHg production and the conditions that affect the availability of inorganic Hg to SRB, much remains to be understood about the biochemical mechanism of the Hg methylation process in SRB, especially in the biofilm-growth of these microbes. Data from our previous study with SRB strains isolated from a coastal wetland suggested that the specific Hg methylation rate found was approximately an order of magnitude higher in biofilm cells than in planktonic cells. In order to investigate possible reasons for this observed difference, and to test if this phenomenon is observed in other strains, we conducted chloroform, fluroacetate and molybdate inhibition assays in both complete and incomplete-oxidizing SRB species (Desulfovibrio desulfuricans M8, Desulfococcus sp

  7. Screening on DHA-producing Antarctic bacteria N- 6 and its cultural conditions

    Institute of Scientific and Technical Information of China (English)

    Zhang Botao; Miao Jin-lai; Hui Hanxing; Wang Qing

    2006-01-01

    In Antarctic, the geography and climate differs from those in other places,and the bacteria there have adapted well to the environment there. Two hundred strains of bacteria were isolated from the sea ice in Antarctica. The bacteria were screened for DHA by means of GC, with fish oil as the standard. Seven strains containing DHA or EPA were obtained, among which the strain of No. N-6 was outstanding. And the component of DHA was identified by GC-MS. The relative content of DHA in N-6 was 8.72%, and total lipids in dry bacteria was 22.54%. The effects of some factors, including temperature, salinity and pH value, on the growth and DHAcontent of strain N-6 were studied. The results show that the DHA-content is relatively high when in low temperature and high pH, and the bacterium is psychrophilic, alkalophilic.

  8. Cultural and morphological properties of the vaccine strain Yersinia pestis EV NIIEG bacteria after photodynamic inactivation

    Science.gov (United States)

    Ulianova, Onega V.; Lyapina, Anna M.; Khizhnyakova, Mariya A.; Laskavy, Vladislav N.; Feodorova, Valentina A.; Ulyanov, Sergey S.

    2015-03-01

    New method of photoinactivation of plague microbes (bacteria Yersinia pestis) has been suggested. Rate of growth of colonies of Y. pestis EV NIIEG at specific regimes of photo processing have been analyzed. Dependence of growth on exposure time and concentrations of photosensitizer (methylene blue) has been studied. Number of colony forming units of Y. pestis EV NIIEG bacteria as a function of intensity of light and concentration of methylene blue has been scrutinized.

  9. Culture-independent characterization of bacteria and fungi in a poultry bioaerosol using pyrosequencing: a new approach.

    Science.gov (United States)

    Nonnenmann, M W; Bextine, B; Dowd, S E; Gilmore, K; Levin, J L

    2010-12-01

    Work in animal production facilities often results in exposure to organic dusts. Previous studies have documented decreases in pulmonary function and lung inflammation among workers exposed to organic dust in the poultry industry. Bacteria and fungi have been reported as components of the organic dust produced in poultry facilities. To date, little is known about the diversity and concentration of bacteria and fungi inside poultry buildings. All previous investigations have utilized culture-based methods for analysis that identify only biota cultured on selected media. The bacterial tag-encoded flexible (FLX) amplicon pyrosequencing (bTEFAP) and fungal tag-encoded flexible (FLX) amplicon pyrosequencing (fTEFAP) are modern and comprehensive approaches for determining biodiversity of microorganisms and have not previously been used to provide characterization of exposure to microorganisms in an occupational environment. This article illustrates the potential application of this novel technique in occupational exposure assessment as well as other settings. An 8-hr area sample was collected using an Institute of Medicine inhalable sampler attached to a mannequin in a poultry confinement building. The sample was analyzed using bTEFAP and fTEFAP. Of the bacteria and fungi detected, 116 and 39 genera were identified, respectively. Among bacteria, Staphylococcus cohnii was present in the highest proportion (23%). The total inhalable bacteria concentration was estimated to be 7503 cells/m³. Among the fungi identified, Sagenomella sclerotialis was present in the highest proportion (37%). Aspergillus ochraceus and Penicillium janthinellum were also present in high proportions. The total inhalable fungi concentration was estimated to be 1810 cells/m³. These estimates are lower than what has been reported by others using standard epifluorescence microscope methods. However, no study has used non-culture-based techniques, such as bTEFAP and fTEFAP, to evaluate bacteria and

  10. Liquid chromatography-mass spectrometry for metabolic footprinting of co-cultures of lactic and propionic acid bacteria

    DEFF Research Database (Denmark)

    Honore, Anders H.; Thorsen, Michael; Skov, Thomas

    2013-01-01

    Co-cultures of specific lactic and propionic acid bacteria have been shown to have an antagonistic effect against yeast and moulds in dairy systems. In studies of these co-cultures by bioassay-guided fractionation and analysis, numerous compounds have been reported to inhibit yeast and moulds...... could be a potent approach to elucidation of the mechanism. The purpose of this review is to discuss the two pre-requisites for such a study-the compound classes expected in the co-cultures, and on the basis of these, the most suitable analytical technique(s). Ultrahigh-performance liquid chromatography....... The strategy recommended in this study does not include all compound classes, and suggestions for supplementary methods are listed....

  11. 16SrRNA and enzymatic diversity of culturable bacteria from the sediments of oxygen minimum zone in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Divya, B.; Soumya, K.V.; Nair, S.

    recycling of organic matter. This study has for the first time addressed the phylogenetic and functional description of culturable bacteria of this region. Genotypic characterization of the isolates using amplified rDNA restriction analysis (ARDRA) followed...

  12. Selection of lactic acid bacteria from Brazilian kefir grains for potential use as starter or probiotic cultures.

    Science.gov (United States)

    Zanirati, Débora Ferreira; Abatemarco, Mário; Sandes, Sávio Henrique de Cicco; Nicoli, Jacques Robert; Nunes, Álvaro Cantini; Neumann, Elisabeth

    2015-04-01

    Brazilian kefir is a homemade fermented beverage that is obtained by incubating milk or a brown sugar solution with kefir grains that contribute their different microbiological compositions. It is highly important to isolate and characterize microorganisms from Brazilian kefir grains to obtain starter cultures for the industrial production of a standardized commercial kefir. Thus, the present study aimed to isolate lactic acid bacteria from eight kefir grains that were propagated in milk or sugar solutions from five different locations in Brazil and to select Lactobacillus isolates based on desirable in vitro probiotic properties. One hundred eight isolates from both substrates were identified by amplified ribosomal DNA restriction analysis and/or 16S rRNA gene sequencing and were determined to belong to the following 11 species from the genera: Lactococcus, Leuconostoc, Lactobacillus (L.), and Oenococcus. Leuconostoc mesenteroides, Lactobacillus kefiri, and Lactobacillus kefiranofaciens were isolated only from milk grains, whereas Lactobacillus perolens, Lactobacillus parafarraginis, Lactobacillus diolivorans, and Oenococcus oeni were isolated exclusively from sugar water grains. When the microbial compositions of four kefir grains were evaluated with culture-independent analyses, L. kefiranofaciens was observed to predominant in milk grains, whereas Lactobacillus hilgardii was most abundant in sugar water kefir. Unfortunately, L. hilgardii was not isolated from any grain, although this bacteria was detected with a culture-independent methodology. Fifty-two isolated Lactobacilli were tested for gastric juice and bile salt tolerance, antagonism against pathogens, antimicrobial resistance, and surface hydrophobicity. Three Lactobacillus strains (L. kefiranofaciens 8U, L. diolivorans 1Z, and Lactobacillus casei 17U) could be classified as potential probiotics. In conclusion, several lactic acid bacteria that could be used in combination with yeasts as starter

  13. Evaluation of dry sheet medium culture plate (Compactdry TC) method for determining numbers of bacteria in food samples.

    Science.gov (United States)

    Mizuochi, S; Kodaka, H

    2000-05-01

    The Compactdry, a ready-to-use and self-diffusible dry medium sheet culture system, has been developed by the Nissui Pharmaceutical Co. Ltd. for enumerating bacteria in food. The Compactdry consists of special spread sheet with culture medium that is the same as standard method nutrients, a cold water-soluble gelling agent, and a unique plastic dish. The procedure for bacterial examination in a sample solution (1 ml) is to just inoculate a test solution into the center of the self-diffusible medium and incubate at 35 degrees C for 48 h. The Compactdry TC (CTC) for the enumeration of total aerobic bacteria from 97 food samples was compared with the standard plate count (SPC) method and 3M Petrifilm aerobic count plates (PAC). The correlation coefficients between the CTC and SPC method, the CTC and PAC, and the PAC and SPC method were 0.97, 0.99, and 0.97, respectively. The Compactdry system is useful for the enumeration of total aerobic bacteria in food and may be a possible suitable alternative to the conventional pour-plate or the Petrifilm plate methods.

  14. Evaluating Nitrogen-Containing Biosynthetic Products Produced by Saltwater Culturing of Several California Littoral Zone Gram-Negative Bacteria.

    Science.gov (United States)

    Lorig-Roach, Nicholas; Still, Patrick C; Coppage, David; Compton, Jennifer E; Crews, Mitchell S; Navarro, Gabriel; Tenney, Karen; Crews, Phillip

    2017-08-25

    The biosynthetic potential of marine-sediment-derived Gram-negative bacteria is poorly understood. Sampling of California near-shore marine environments afforded isolation of numerous Gram-negative bacteria in the Proteobacteria and Bacteriodetes phyla, which were grown in the laboratory to provide extracts whose metabolites were identified by comparative analyses of LC-mass spectrometry and MS(n) data. Overall, we developed an assemblage of seven bacterial strains grown in five different media types designed to coax out unique secondary metabolite production as a function of varying culture conditions. The changes in metabolite production patterns were tracked using the GNPS MS(2) fragmentation pattern analysis tool. A variety of nitrogen-rich metabolites were visualized from the different strains grown in different media, and strikingly, all of the strains examined produced the same new, proton-atom-deficient compound, 1-methyl-4-methylthio-β-carboline (1), C13H12N2S. Scale-up liquid culture of Achromobacter spanius (order: Burkholderiales; class: Betaproteobacteria) provided material for the final structure elucidation. The methods successfully combined in this work should stimulate future studies of molecules from marine-derived Gram-negative bacteria.

  15. Validation of the H2S method to detect bacteria of fecal origin by cultured and molecular methods.

    Science.gov (United States)

    McMahan, Lanakila; Devine, Anthony A; Grunden, Amy M; Sobsey, Mark D

    2011-12-01

    Using biochemical and molecular methods, this research determined whether or not the H(2)S test did correctly identify sewage-contaminated waters by being the first to use culturing and molecular methods to identify the types and numbers of fecal indicator organisms, pathogens, and other microbes present in sewage samples with positive H(2)S test results. For the culture-based method, samples were analyzed for the presence of fecal bacteria by spread plating the sewage sample onto differential and selective media for Aeromonas spp., Escherichia coli, sulfite-reducing clostridia, H(2)S-producing bacteria, and Salmonella/Shigella spp. The isolates were then: (1) tested to determine whether they were H(2)S-producing organisms and (2) identified to the genus and species level using biochemical methods. The molecular method used to characterize the microbial populations of select samples was terminal restriction fragment length polymorphisms. These experiments on sewage provided evidence that positive H(2)S tests consistently contained fecal bacteria and pathogens. There were strong relationships of agreement between the organisms identified by both methods tested. This study is an important advance in microbial water quality detection since it is focused on the evaluation of a novel, low-cost, water microbiology test that has the potential to provide millions of people worldwide access to water quality detection technology. Of prime consideration in evaluating water quality tests is the determination of the test's accuracy and specificity, and this article is a fundamental step in providing that information.

  16. Influence of an aerobic fungus grown on solid culture on ruminal degradability and on a mixture culture of anaerobic cellulolytic bacteria.

    Science.gov (United States)

    Hernández-Díaz, R; Pimentel-González, D J; Figueira, A C; Viniegra-González, G; Campos-Montiel, R G

    2010-06-01

    In this work, the effect of a solid fungal culture of Aspergillus niger (An) grown on coffee pulp on the in situ ruminal degradability (RD) of corn stover was evaluated. In addition, the effect of its extracts on the in vitro dry matter disappearance (IVDMD) and on a mixed culture of anaerobic cellulolytic bacteria (MCACB) was also investigated. The solid ferment was a crude culture of An, grown on coffee pulp. Regarding in situ RD, a significant difference (p < 0.05) was found between treatment with 200 g/day of the solid culture and control (no solid culture added) on dry matter, crude protein and neutral detergent fibre on RD. All the water extracts (pH 4, 7 and 10) enhanced IVDMD and stimulated the cellulolytic activity on a MCACB. Ultrafiltration results showed that active compounds with a molecular weight lower than 30 kDa were responsible for the effect on MCACB. Such results suggest that the effects of the solid An culture in RD are related to the presence of water soluble compounds having a molecular weight lower than 30 kDa.

  17. Heavy metal bioleaching and sludge stabilization in a single-stage reactor using indigenous acidophilic heterotrophs.

    Science.gov (United States)

    Mehrotra, Akanksha; Sreekrishnan, T R

    2017-01-10

    Simultaneous sludge digestion and metal leaching (SSDML) have been reported at mesophilic temperature. It is generally perceived that while sludge stabilization is effected by heterotrophs at neutral pH, metal bioleaching is done by acidophilic autotrophs. However, little information is available on the microbial communities involved in the process. This study carried out SSDML in a single-stage reactor using sludge indigenous microorganisms and looked at the bacterial communities responsible for the process. Volatile suspended solids were reduced by more than 40%. The concentration of zinc, copper, chromium, cadmium and nickel decreased by more than 45% in the dry sludge. Acidophilic species of Alicyclobacillus genus were the dominant heterotrophs. A few heterotrophic bacteria were detected which can oxidize iron (Alicyclobacillus ferrooxydans, Alicyclobacillus ferripilum and Ferrimicrobium acidiphilum). Acidithiobacillus ferrooxidans (autotroph) was responsible for the oxidation of both iron and sulfur which lead to a change in the pH from neutral to acidic. The presence of acidophilic heterotrophs, which can oxidize either iron or sulfur, enhanced the efficiency of SSDML process with respect to sludge stabilization and metal leaching. This study shows that it is possible to carry out the SSDML in a single-stage reactor with indigenous microorganisms.

  18. Quantamatrix Multiplexed Assay Platform system for direct detection of bacteria and antibiotic resistance determinants in positive blood culture bottles.

    Science.gov (United States)

    Wang, H Y; Uh, Y; Kim, S; Lee, H

    2017-05-01

    Rapid and accurate identification of the causative pathogens of bloodstream infections (BSIs) is crucial for initiating appropriate antimicrobial therapy, which decreases the related morbidity and mortality rates. The aim of this study was to evaluate the usefulness of a newly developed multiplexed, bead-based bioassay system, the Quantamatrix Multiplexed Assay Platform (QMAP) system, obtained directly from blood culture bottles, to simultaneously detect the presence of bacteria and identify the genes for antibiotic resistance. The QMAP system was used to evaluate 619 blood culture bottles from patients with BSIs and to compare the results of conventional culture methods. Using conventional bacterial cultures as the reference standard, the sensitivity, specificity, positive predictive value, and negative predictive value of the QMAP system for detection of bacterial pathogens in positive blood culture (PBC) samples were 99.8% (n=592, 95% CI 0.9852-1.000, p system for identification of the genes for antibiotic resistance were 99.4% (n=158, 95% CI 0.9617-0.9999, p system takes about 3 hr, while culture methods can take 48-72 hr. Therefore, analysis using the QMAP system is rapid and reliable for characterizing causative pathogens in BSIs. Copyright © 2016 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  19. Identification of bacteria associated with feline chronic gingivostomatitis using culture-dependent and culture-independent methods

    OpenAIRE

    Dolieslager, Sanne M.J.; Riggio, Marcello P; Lennon, Alan; Lappin, David F; Johnston, Norman; Taylor, David; Bennett, David

    2011-01-01

    Abstract Feline chronic gingivostomatitis (FCGS) is a chronic inflammatory disease of the oral cavity that causes severe pain and distress. There are currently no specific treatment methods available and little is known regarding its aetiology, although bacteria are thought to play a major role. The purpose of this study was to identify the oral bacterial flora in normal and diseased cats. Oral swabs were obtained from the palatoglossal folds of eight cats (three normal, five FCGS)...

  20. [Staining of sulfate-reducing bacteria with hexacyanoferrat-compounds (cultural and cytochemical evidence of Fe) (author's transl)].

    Science.gov (United States)

    Stübner, G

    1978-04-01

    Hexacyanoferrat-compounds are suitable 1. to indicate the valence of Fe-ions in cultures of desulfuricants (Desulfovibrio spec., Desulfotomaculum) in fluid and solid medium before and after inoculation; 2. stain directly the sulfate-reducing bacteria in presence of Fe-ions and give a colour-reaction of those parts of the cell containing Fe-compounds, e.g. FeS. Therefore they act as a cytochemical indicator system. The chemical base of the reactions are as follows: (1) 4HS + SO42 leads to H2S + 2H2O + OH- H2S leads to H+ + HS- leads to 2H+ + S2- (in the bacteria) (2) FeIII-salt + S2-leads to Fe2S3 leads to 2FeIIS + S 2FeIIS + FeIII(CN6) leads to FeIIIFeII(CN)6 (blue complex-compound).

  1. Interspecies interactions result in enhanced biofilm formation by co-cultures of bacteria isolated from a food processing environment

    DEFF Research Database (Denmark)

    Røder, Henriette Lyng; Raghupathi, Prem Krishnan; Herschend, Jakob

    2015-01-01

    examined for multispecies biofilm formation. Eight strains from each sampling site were chosen and all possible combinations of four member co-cultures were tested for enhanced biofilm formation at 15°C and 24°C. In approximately 20% of the multispecies consortia grown at 15°C, the biofilm formation......Bacterial attachment and biofilm formation can lead to poor hygienic conditions in food processing environments. Furthermore, interactions between different bacteria may induce or promote biofilm formation. In this study, we isolated and identified a total of 687 bacterial strains from seven...... different locations in a meat processing environment and evaluated their biofilm formation capability. A diverse group of bacteria was isolated and most were classified as poor biofilm producers in a Calgary biofilm device assay. Isolates from two sampling sites, the wall and the meat chopper, were further...

  2. Culture-independent detection of "TM7" bacteria in a streptomycin-resistant acidophilic nitrifying process

    Science.gov (United States)

    Kurogi, T.; Linh, N. T. T.; Kuroki, T.; Yamada, T.; Hiraishi, A.

    2014-02-01

    Nitrification in biological wastewater treatment processes has been believed for long time to take place under neutral conditions and is inhibited under acidic conditions. However, we previously constructed acidophilic nitrifying sequencing-batch reactors (ANSBRs) being capable of nitrification at level, this study was undertaken to construct streptomycin-resistant acidophilic nitrifying (SRAN) reactors and to demonstrate whether TM7 bacteria are abundant in these reactors. The SRAN reactors were constructed by seeding with nitrifying sludge from an ANSBR and cultivating with ammonium-containing mineral medium (pH 4.0), to which streptomycin at a concentration of 10, 30 and 50 mg L-1 was added. In all reactors, the pH varied between 2.7 and 4.0, and ammonium was completely converted to nitrate in every batch cycle. PCR-aided denaturing gradient gel electrophoresis (DGGE) targeting 16S rRNA genes revealed that some major clones assigned to TM7 bacteria and Gammaproteobacteria were constantly present during the overall period of operation. Fluorescence in situ hybridization (FISH) with specific oligonucleotide probes also showed that TM7 bacteria predominated in all SRAN reactors, accounting for 58% of the total bacterial population on average. Although the biological significance of the TM7 bacteria in the SRAN reactors are unknown, our results suggest that these bacteria are possibly streptomycin-resistant and play some important roles in the acidophilic nitrifying process.

  3. Characterization of lactic acid bacteria isolated from infant faeces as potential probiotic starter cultures for fermented sausages.

    Science.gov (United States)

    Rubio, Raquel; Jofré, Anna; Martín, Belén; Aymerich, Teresa; Garriga, Margarita

    2014-04-01

    A total of 109 lactic acid bacteria isolated from infant faeces were identified by partial 16S rRNA, cpn60 and/or pheS sequencing. Lactobacillus was the most prevalent genus, representing 48% of the isolates followed by Enterococcus (38%). Lactobacillus gasseri (21%) and Enterococcus faecalis (38%) were the main species detected. A further selection of potential probiotic starter cultures for fermented sausages focused on Lactobacillus as the most technologically relevant genus in this type of product. Lactobacilli strains were evaluated for their ability to grow in vitro in the processing conditions of fermented sausages and for their functional and safety properties, including antagonistic activity against foodborne pathogens, survival from gastrointestinal tract conditions (acidity, bile and pancreatin), tyramine production, antibiotic susceptibility and aggregation capacity. The best strains according to the results obtained were Lactobacillus casei/paracasei CTC1677, L. casei/paracasei CTC1678, Lactobacillus rhamnosus CTC1679, L. gasseri CTC1700, L. gasseri CTC1704, Lactobacillus fermentum CTC1693. Those strains were further assayed as starter cultures in model sausages. L. casei/paracasei CTC1677, L. casei/paracasei CTC1678 and L. rhamnosus CTC1679 were able to lead the fermentation and dominate (levels ca. 10(8) CFU/g) the endogenous lactic acid bacteria, confirming their suitability as probiotic starter cultures.

  4. Evaluation of antibiotics as a methodological procedure to inhibit free-living and biofilm bacteria in marine zooplankton culture

    Directory of Open Access Journals (Sweden)

    Vanessa O. Agostini

    2016-01-01

    Full Text Available There is a problem with keeping culture medium completely or partially free from bacteria. The use of prokaryotic metabolic inhibitors, such as antibiotics, is suggested as an alternative solution, although such substances should not harm non-target organisms. Thus, the aim of this study was to assess the effectiveness of antibiotic treatments in inhibiting free-living and biofilm bacteria and their half-life in artificial marine environment using the copepod Acartia tonsa as bioindicador of non-harmful antibiotic combinations. Regarding to results, the application of 0.025 g L-1 penicillin G potassium + 0.08 g L-1 streptomycin sulphate + 0.04 g L-1 neomycin sulphate showed great potential for use in marine cultures and scientific experiments without lethal effects to non-target organisms. The effect of this combination starts within the first six hours of exposure and reduces up to 93 % the bacterial density, but the half-life is short, requiring replacement. No adverse changes in water quality were observed within 168 hours of exposure. As a conclusion, we can infer that this treatment was an effective procedure for zooplankton cultures and scientific experiments with the aim of measuring the role of free-living and biofilm in the marine community.

  5. Endophytic bacteria in plant tissue culture: differences between easy- and difficult-to-propagate Prunus avium genotypes.

    Science.gov (United States)

    Quambusch, Mona; Pirttilä, Anna Maria; Tejesvi, Mysore V; Winkelmann, Traud; Bartsch, Melanie

    2014-05-01

    The endophytic bacterial communities of six Prunus avium L. genotypes differing in their growth patterns during in vitro propagation were identified by culture-dependent and culture-independent methods. Five morphologically distinct isolates from tissue culture material were identified by 16S rDNA sequence analysis. To detect and analyze the uncultivable fraction of endophytic bacteria, a clone library was established from the amplified 16S rDNA of total plant extract. Bacterial diversity within the clone libraries was analyzed by amplified ribosomal rDNA restriction analysis and by sequencing a clone for each identified operational taxonomic unit. The most abundant bacterial group was Mycobacterium sp., which was identified in the clone libraries of all analyzed Prunus genotypes. Other dominant bacterial genera identified in the easy-to-propagate genotypes were Rhodopseudomonas sp. and Microbacterium sp. Thus, the community structures in the easy- and difficult-to-propagate cherry genotypes differed significantly. The bacterial genera, which were previously reported to have plant growth-promoting effects, were detected only in genotypes with high propagation success, indicating a possible positive impact of these bacteria on in vitro propagation of P. avium, which was proven in an inoculation experiment.

  6. Heterotrophic bacterial production and metabolic balance during the VAHINE mesocosm experiment in the New Caledonia lagoon

    Science.gov (United States)

    Van Wambeke, France; Pfreundt, Ulrike; Barani, Aude; Berthelot, Hugo; Moutin, Thierry; Rodier, Martine; Hess, Wolfgang R.; Bonnet, Sophie

    2016-06-01

    Studies investigating the fate of diazotrophs through the microbial food web are lacking, although N2 fixation can fuel up to 50 % of new production in some oligotrophic oceans. In particular, the role played by heterotrophic prokaryotes in this transfer is largely unknown. In the frame of the VAHINE (VAriability of vertical and tropHIc transfer of diazotroph derived N in the south wEst Pacific) experiment, three replicate large-volume (˜ 50 m3) mesocosms were deployed for 23 days in the new Caledonia lagoon and were intentionally fertilized on day 4 with dissolved inorganic phosphorus (DIP) to stimulate N2 fixation. We specifically examined relationships between heterotrophic bacterial production (BP) and N2 fixation or primary production, determined bacterial growth efficiency and established carbon budgets. BP was statistically higher during the second phase of the experiment (P2: days 15-23), when chlorophyll biomass started to increase compared to the first phase (P1: days 5-14). Phosphatase alkaline activity increased drastically during the second phase of the experiment, showing adaptations of microbial populations after utilization of the added DIP. Notably, among autotrophs, Synechococcus abundances increased during P2, possibly related to its capacity to assimilate leucine and to produce alkaline phosphatase. Bacterial growth efficiency based on the carbon budget (27-43 %), was notably higher than generally cited for oligotrophic environments and discussed in links with the presence of abundant species of bacteria expressing proteorhodopsin. The main fates of gross primary production (particulate + dissolved) were respiration (67 %) and export through sedimentation (17 %). BP was highly correlated with particulate primary production and chlorophyll biomass during both phases of the experiment but was slightly correlated, and only during P2 phase, with N2 fixation rates. Heterotrophic bacterial production was strongly stimulated after mineral N enrichment

  7. Optimization of an effective growth medium for culturing probiotic bacteria for applications in strict vegetarian food products

    Directory of Open Access Journals (Sweden)

    Manju Pathak

    2012-10-01

    Full Text Available Background: This study aimed to modify de Man Rogosa Sharpe culture medium (termed MRS for selective cultivation of probiotics strain for the consumption by the strictly vegetarian human population. Vegetarian probiotic foods by definition must be free from all animal-derived ingredients. This not only includes the product ingredients but the probiotic inoculum as well. Probiotic starter cultures are traditionally grown and stored in media containing milk or meatderived ingredients. The presence of these ingredients makes the probiotic cell concentrates unsuitable for use in vegetarian products and thus creates the need for a growth medium which isfree from animal-derived ingredients. Present study investigated the growth of a strain of Lactobacillus lactis in MRS. The present invention relates in general to a bacterial culture media,and more specifically a complex microbial culture media, based on plant seed powder extract in place of animal extract for probiotic bacterial growth.Methods: Lactobacillus lactis, a probiotic, was grown in standard MRS culture medium as well as in our various test media (TM containing various vegetal source in place of beef extract, yeast extract and peptone as in case of MRS. The inoculated culture mediums were incubated at 37C for 72 hours and growth of probiotic is recorded at regular intervals. The growth was recorded as Colony Forming Units (CFUs.Results: The best growth of probiotic is observed in TM 2. TM 2 is the leguminous seed extract. Starter culture mediums for probiotics or other bacteria primarily contain protein from animal source. The possibility of using vegetal protein from TM 2 extract in place of peptones and meat extract for the nitrogen supplementation of culture media for the growth of lactic acid bacteria has been demonstrated.Functional Foods in Health and Disease 2012, 2(10:369-378 Conclusion: The absolute vegetarian culture medium containing TM 2 is better than standard MRS for the

  8. Multiwavelength Resonance Raman Characterization of the Effect of Growth Phase and Culture Medium on Bacteria.

    Science.gov (United States)

    Kunapareddy, Nagapratima; Grun, Jacob; Lunsford, Robert; Nikitin, Sergei; Wang, Zheng; Gillis, David

    2015-08-01

    We examine the use of multiwavelength ultraviolet (UV) resonance-Raman signatures to identify the effects of growth phase and growth medium on gram-positive and gram-negative bacteria. Escherichia coli (E. coli), Citrobacter koseri (C. koseri), Citrobacter braakii (C. braakii), and Bacillus cereus (B. cereus) were grown to logarithmic and stationary phases in nutrient broth and brain heart infusion broth. Resonance Raman spectra of bacteria were obtained at multiple wavelengths between 220 and 260 nm; a range that encompasses the resonance frequencies of cellular constituents. We find that spectra of the same bacterial species exhibit differences due to both growth condition and growth phase, but the larger differences reflect changes due to growth phase. The differences in the Raman spectra correlate with genetic differences among the species. Using a Pearson correlation based algorithm, we achieve successful identification of these bacteria in 83% of the cases.

  9. Growth Characteristics of Tetraselmis sp.-1 in Phototrophic, Mixotrophic and Heterotrophic Conditions

    Institute of Scientific and Technical Information of China (English)

    Shen Jihong(沈继红); Yu Junhong; Lin Xuezheng; Li Guangyou; Liu Fayi

    2004-01-01

    Tetraselmis sp.-1 is a new microalgae strain constructed by cell fusion technique. In this paper, the growth characteristics of Tetraselmis sp.-1 under different culture conditions are investigated. The growth kinetic models are obtained, the assimilation of C and NH4+ is investigated and the assimilation efficiency of Tetraselmis sp.-1 under different culture conditions is calculated. The results show that different culture conditions do not have obvious influence on carbon absorbance, but have significant influence on nitrogen absorbance, C∶N is maximum under heterotrophic condition, while minimum under phototrophic condition. The assimilation efficiency (η) of Tetraselmis sp.-1 has the highest value in heterotrophic condition and largely higher than those in phototrophic and mixotrophic conditions.

  10. Some low homogenization pressures improve certain probiotic characteristics of yogurt culture bacteria and Lactobacillus acidophilus LA-K.

    Science.gov (United States)

    Muramalla, T; Aryana, K J

    2011-08-01

    Lactobacillus delbrueckii ssp. bulgaricus, Streptococcus salivarius ssp. thermophilus, and Lactobacillus acidophilus are dairy cultures widely used in the manufacture of cultured dairy products. Commonly used homogenization pressures in the dairy industry are 13.80 MPa or less. It is not known whether low homogenization pressures can stimulate bacteria to improve their probiotic characteristics. Objectives were to determine the effect of homogenization at 0, 3.45, 6.90, 10.34, and 13.80 MPa on acid tolerance, bile tolerance, protease activity, and growth of L. delbrueckii ssp. bulgaricus LB-12, S. salivarius ssp. thermophilus ST-M5, and L. acidophilus LA-K. The cultures were individually inoculated in cool autoclaved skim milk (4°C) and homogenized for 5 continuous passes. Growth and bile tolerance of samples were determined hourly for 10h of incubation. Acid tolerance was determined every 20 min for 120 min of incubation. Protease activity was determined at 0, 12, and 24h of incubation. All homogenization pressures studied improved acid tolerance of L. delbrueckii ssp. bulgaricus LB-12 but had no beneficial effect on protease activity and had negative effects on growth and bile tolerance. A pressure of 6.90 MPa improved acid tolerance, bile tolerance, and protease activity of S. salivarius ssp. thermophilus ST-M5, but none of the homogenization pressures studied had an effect on its growth. Homogenization pressures of 13.80 and 6.90 MPa improved acid tolerance and bile tolerance, respectively, of L. acidophilus LA-K but had no effect on protease activity and its growth. Some low homogenization pressures positively influenced some characteristics of yogurt culture bacteria and L. acidophilus LA-K. Culture pretreatment with some low homogenization pressures can be recommended for improvement of certain probiotic characteristics. Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  11. Evaluation of the Verigene Gram-positive blood culture nucleic acid test for rapid detection of bacteria and resistance determinants.

    Science.gov (United States)

    Wojewoda, Christina M; Sercia, Linda; Navas, Maria; Tuohy, Marion; Wilson, Deborah; Hall, Geraldine S; Procop, Gary W; Richter, Sandra S

    2013-07-01

    Rapid identification of pathogens from blood cultures can decrease lengths of stay and improve patient outcomes. We evaluated the accuracy of the Verigene Gram-positive blood culture (BC-GP) nucleic acid test for investigational use only (Nanosphere, Inc., Northbrook, IL) for the identification of Gram-positive bacteria from blood cultures. The detection of resistance genes (mecA in Staphylococcus aureus and Staphylococcus epidermidis and vanA or vanB in Enterococcus faecium and Enterococcus faecalis) by the BC-GP assay also was assessed. A total of 186 positive blood cultures (in BacT/Alert FA bottles) with Gram-positive cocci observed with Gram staining were analyzed using the BC-GP assay. The BC-GP results were compared with the identification and susceptibility profiles obtained with routine methods in the clinical laboratory. Discordant results were arbitrated with additional biochemical, cefoxitin disk, and repeat BC-GP testing. The initial BC-GP organism identification was concordant with routine method results for 94.6% of the blood cultures. Only 40% of the Streptococcus pneumoniae identifications were correct. The detection of the mecA gene for 69 blood cultures with only S. aureus or S. epidermidis was concordant with susceptibility testing results. For 3 of 6 cultures with multiple Staphylococcus spp., mecA detection was reported but was correlated with oxacillin resistance in a species other than S. aureus or S. epidermidis. The detection of vanA agreed with susceptibility testing results for 45 of 46 cultures with E. faecalis or E. faecium. Comparison of the mean times to results for each organism group showed that BC-GP results were available 31 to 42 h earlier than phenotypic identifications and 41 to 50 h earlier than susceptibility results.

  12. Enrichment and Characterization of PCB-Degrading Bacteria as Potential Seed Cultures for Bioremediation of Contaminated Soil

    Directory of Open Access Journals (Sweden)

    Dubravka Hršak

    2007-01-01

    Full Text Available The main objective of our study was to obtain seed cultures for enhancing the transformation of polychlorinated biphenyls (PCBs in contaminated soil of the transformer station in Zadar, Croatia, damaged during warfare activities in 1991. For enrichment, six soil samples were collected from different polluted areas and microcosm approach, stimulating the growth of biphenyl-degrading bacteria, was employed. Enrichment experiments resulted in the selection of two fast growing mixed cultures TSZ7 and AIR1, originating from the soil of the transformer station and the airport area, respectively. Both cultures showed significant PCB-degrading activity (56 to 60 % of PCB50 mixture was reduced after a two-week cultivation. Furthermore, the cultures displayed similar PCB-degrading competence and reduced di-to tetrachlorobiphenyls more effectively than penta- to hepta-chlorobiphenyls. Strain Z6, identified as Rhodococcus erythropolis, was found to be the only culture member showing PCB-transformation potential similar to that of the mixed culture TSZ7, from which it was isolated. Based on the metabolites identified in the assay with the single congener 2,4,4’-chlorobiphenyl, we proposed that the strain Z6 was able to use both the 2,3-and 3,4-dioxygenase pathways. Furthermore, the identified metabolites suggested that beside these pathways another unidentified pathway might also be active in strain Z6. Based on the obtained results, the culture TSZ7 and the strain Z6 were designated as potential seed cultures for bioremediation of the contaminated soil.

  13. A new approach to determine the susceptibility of bacteria to antibiotics directly from positive blood culture bottles in two hours.

    Science.gov (United States)

    March, Gabriel A; García-Loygorri, María C; Simarro, María; Gutiérrez, María P; Orduña, Antonio; Bratos, Miguel A

    2015-02-01

    The rapid identification and antibiotic susceptibility test of bacteria causing bloodstream infections are given a very high priority by clinical laboratories. In an effort to reduce the time required for performing antibiotic susceptibility test (AST), we have developed a new method to be applied from positive blood culture bottles. The design of method was performed using blood culture bottles prepared artificially with five strains which have a known susceptibility. An aliquot of the blood culture was subcultured in the presence of specific antibiotics and bacterial counts were monitored using the Sysmex UF-1000i flow cytometer at different times up to 180min. Receiver operating curve (ROC) analysis allowed us to find out the cut-off point for differentiating between sensitive and resistant strains to the tested antibiotic. This procedure was then validated against standard commercial methods on a total of 100 positive blood culture bottles from patients. First, bacterial identification was performed by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS) directly from positive blood culture bottles as we have previously reported. Secondly, antibiotic susceptibility test was performed in the same way that was carried out in artificially prepared blood culture bottles. Our results indicate that antibiotic susceptibility test can be determined as early as 120min since a blood culture bottle is flagged as positive. The essential agreement between our susceptibility test and commercial methods (E-test, MicroScan and Vitek) was 99%. In summary, we conclude that reliable results on bacterial identification and antibiotic susceptibility test performed directly from positive blood culture bottles can be obtained within 3h.

  14. Citric acid cycle in the hyperthermophilic archaeon Pyrobaculum islandicum grown autotrophically, heterotrophically, and mixotrophically with acetate.

    Science.gov (United States)

    Hu, Yajing; Holden, James F

    2006-06-01

    The hyperthermophilic archaeon Pyrobaculum islandicum uses the citric acid cycle in the oxidative and reductive directions for heterotrophic and autotrophic growth, respectively, but the control of carbon flow is poorly understood. P. islandicum was grown at 95 degrees C autotrophically, heterotrophically, and mixotrophically with acetate, H2, and small amounts of yeast extract and with thiosulfate as the terminal electron acceptor. The autotrophic growth rates and maximum concentrations of cells were significantly lower than those in other media. The growth rates on H2 and 0.001% yeast extract with and without 0.05% acetate were the same, but the maximum concentration of cells was fourfold higher with acetate. There was no growth with acetate if 0.001% yeast extract was not present, and addition of H2 to acetate-containing medium greatly increased the growth rates and maximum concentrations of cells. P. islandicum cultures assimilated 14C-labeled acetate in the presence of H2 and yeast extract with an efficiency of 55%. The activities of 11 of 19 enzymes involved in the central metabolism of P. islandicum were regulated under the three different growth conditions. Pyruvate synthase and acetate:coenzyme A (CoA) ligase (ADP-forming) activities were detected only in heterotrophically grown cultures. Citrate synthase activity decreased in autotrophic and acetate-containing cultures compared to the activity in heterotrophic cultures. Acetylated citrate lyase, acetate:CoA ligase (AMP forming), and phosphoenolpyruvate carboxylase activities increased in autotrophic and acetate-containing cultures. Citrate lyase activity was higher than ATP citrate synthase activity in autotrophic cultures. These data suggest that citrate lyase and AMP-forming acetate:CoA ligase, but not ATP citrate synthase, work opposite citrate synthase to control the direction of carbon flow in the citric acid cycle.

  15. Continuous culture enrichments of ammonia-oxidizing bacteria at low ammonium concentrations

    NARCIS (Netherlands)

    Bollmann, A.; Laanbroek, H.J.

    2001-01-01

    Until now enrichments of ammonia-oxidizing bacteria from natural ammonium-limited environments have been performed mainly in the presence of much higher ammonia concentrations than those present in the natural environment and many have resulted in the enrichment and isolation of environmentally less

  16. Distribution of baroduric, psychrotrophic and culturable nitrifying and denitrifying bacteria in the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    LokaBharathi, P.A.; PradeepRam, A.S.; Nair, S.; Nath, B.N.; Chandramohan, D.

    minutes-76 degrees 05 minutes E, showed that nitrifying bacteria were present in layers of sediment 0-25 cm below sea floor (bsf) with maximum numbers at sub-surface layers. Their average numbers ranged from 4.0 x 10 sup(4) to 2.43 x 10 sup(8) CFU g sup(-1...

  17. Quantification of anaerobic ammonium-oxidizing bacteria in enrichment cultures by quantitative competitive PCR

    Institute of Scientific and Technical Information of China (English)

    HAO Chun; WANG Huan; LIU Qinhua; LI Xudong

    2009-01-01

    The anaerobic ammonium-oxidizing (ANAMMOX) bacteria were enriched from a sequencing batch biofilm reactor (SBBR) biofilm.We successfully developed a quantitative competitive polymerase chain reaction (QC-PCR) system to detect and quantify ANAMMOX bacteria in environmental samples.For QC-PCR system,PCR primer sets targeting 16S ribosomal RNA genes of ANAMMOX bacteria were designed and used.The quantification range of this system was 4 orders of magnitude,from 10~3 to 10~6 copies per PCR,corresponding to the detection limit of 300 target copies per mL.A 312-bp internal standard (IS) was constructed,which showed very similar amplification efficiency with the target amxC fragment (349 bp) over 4 orders of magnitude (10~3-10~6).The linear regressions were obtained with a R~2 of 0.9824 for 10~3 copies,R~2 of 0.9882 for 10~4 copies,0.9857 for 10~5 copies and 0.9899 for 10~6 copies.Using this method,we quantified ANAMMOX bacteria in a shortcut nitrification/denitrification-anammox system which is set for piggery wastewater treatment.

  18. Rapid identification of bacteria in blood cultures by using fluorescently labeled oligonucleotide probes

    NARCIS (Netherlands)

    Jansen, GJ; Mooibroek, M; Idema, J; Harmsen, HJM; Welling, GW; Degener, JE

    2000-01-01

    The applicability of whole-cell hybridization for the identification of pathogenic bacteria in blood from septic patients was examined. Oligonucleotide probes, fluorescently labeled with fluorescein isothiocyanate, directed against the variable regions of the 16S rRNAs of the following bacterial spe

  19. 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...

  20. 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...

  1. Jania rubens-associated bacteria: molecular identification and antimicrobial activity

    NARCIS (Netherlands)

    Ismail-Ben Ali, A.; El Bour, M.; Ktari, L.; Bolhuis, H.; Ahmed, M.; Boudabbous, A.; Stal, L.J.

    2012-01-01

    Marine macroalgae surfaces constitute suitable substrata for bacterial colonization which are known to produce bioactive compounds. Thus, hereby we focused on heterotrophic aerobic bacteria species associated with coralline red alga Jania rubens (northern coast of Tunisia, southern Mediterranean Sea

  2. Heterotrophic and autotrophic microbial populations in cold perennial springs of the high arctic.

    Science.gov (United States)

    Perreault, Nancy N; Greer, Charles W; Andersen, Dale T; Tille, Stefanie; Lacrampe-Couloume, Georges; Lollar, Barbara Sherwood; Whyte, Lyle G

    2008-11-01

    The saline springs of Gypsum Hill in the Canadian high Arctic are a rare example of cold springs originating from deep groundwater and rising to the surface through thick permafrost. The heterotrophic bacteria and autotrophic sulfur-oxidizing bacteria (up to 40% of the total microbial community) isolated from the spring waters and sediments were classified into four phyla (Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria) based on 16S rRNA gene analysis; heterotrophic isolates were primarily psychrotolerant, salt-tolerant, facultative anaerobes. Some of the isolates contained genes for thiosulfate oxidation (soxB) and anoxygenic photosynthesis (pufM), possibly enabling the strains to better compete in these sulfur-rich environments subject to long periods of illumination in the Arctic summer. Although leucine uptake by the spring water microbial community was low, CO(2) uptake was relatively high under dark incubation, reinforcing the idea that primary production by chemoautotrophs is an important process in the springs. The small amounts of hydrocarbons in gases exsolving from the springs (0.38 to 0.51% CH(4)) were compositionally and isotopically consistent with microbial methanogenesis and possible methanotrophy. Anaerobic heterotrophic sulfur oxidation and aerobic autotrophic sulfur oxidation activities were demonstrated in sediment slurries. Overall, our results describe an active microbial community capable of sustainability in an extreme environment that experiences prolonged periods of continuous light or darkness, low temperatures, and moderate salinity, where life seems to rely on chemolithoautotrophy.

  3. Killing of Mycolic Acid-Containing Bacteria Aborted Induction of Antibiotic Production by Streptomyces in Combined-Culture.

    Science.gov (United States)

    Asamizu, Shumpei; Ozaki, Taro; Teramoto, Kanae; Satoh, Katsuya; Onaka, Hiroyasu

    2015-01-01

    Co-culture of Streptomyces with mycolic acid-containing bacteria (MACB), which we termed "combined-culture," alters the secondary metabolism pattern in Streptomyces and has been a useful method for the discovery of bioactive natural products. In the course of our investigation to identify the inducing factor(s) of MACB, we previously observed that production of pigments in Streptomyces lividans was not induced by factors such as culture extracts or mycolic acids. Although dynamic changes occurred in culture conditions because of MACB, the activation of pigment production by S. lividans was observed in a limited area where both colonies were in direct contact. This suggested that direct attachment of cells is a requirement and that components on the MACB cell membrane may play an important role in the response by S. lividans. Here we examined whether this response was influenced by dead MACB that possess intact mycolic acids assembled on the outer cell membrane. Formaldehyde fixation and γ-irradiation were used to prepare dead cells that retain their shape and mycolic acids of three MACB species: Tsukamurella pulmonis, Rhodococcus erythropolis, and Rhodococcus opacus. Culturing tests verified that S. lividans does not respond to the intact dead cells of three MACB. Observation of combined-culture by scanning electron microscopy (SEM) indicated that adhesion of live MACB to S. lividans mycelia were a significant interaction that resulted in formation of co-aggregation. In contrast, in the SEM analysis, dead cells were not observed to adhere. Therefore, direct attachment by live MACB cells is proposed as one of the possible factors that causes Streptomyces to alter its specialized metabolism in combined-culture.

  4. Killing of Mycolic Acid-Containing Bacteria Aborted Induction of Antibiotic Production by Streptomyces in Combined-Culture.

    Directory of Open Access Journals (Sweden)

    Shumpei Asamizu

    Full Text Available Co-culture of Streptomyces with mycolic acid-containing bacteria (MACB, which we termed "combined-culture," alters the secondary metabolism pattern in Streptomyces and has been a useful method for the discovery of bioactive natural products. In the course of our investigation to identify the inducing factor(s of MACB, we previously observed that production of pigments in Streptomyces lividans was not induced by factors such as culture extracts or mycolic acids. Although dynamic changes occurred in culture conditions because of MACB, the activation of pigment production by S. lividans was observed in a limited area where both colonies were in direct contact. This suggested that direct attachment of cells is a requirement and that components on the MACB cell membrane may play an important role in the response by S. lividans. Here we examined whether this response was influenced by dead MACB that possess intact mycolic acids assembled on the outer cell membrane. Formaldehyde fixation and γ-irradiation were used to prepare dead cells that retain their shape and mycolic acids of three MACB species: Tsukamurella pulmonis, Rhodococcus erythropolis, and Rhodococcus opacus. Culturing tests verified that S. lividans does not respond to the intact dead cells of three MACB. Observation of combined-culture by scanning electron microscopy (SEM indicated that adhesion of live MACB to S. lividans mycelia were a significant interaction that resulted in formation of co-aggregation. In contrast, in the SEM analysis, dead cells were not observed to adhere. Therefore, direct attachment by live MACB cells is proposed as one of the possible factors that causes Streptomyces to alter its specialized metabolism in combined-culture.

  5. Identification of bacteria directly from positive blood culture samples by DNA pyrosequencing of the 16S rRNA gene.

    Science.gov (United States)

    Motoshima, Maiko; Yanagihara, Katsunori; Morinaga, Yoshitomo; Matsuda, Junichi; Hasegawa, Hiroo; Kohno, Shigeru; Kamihira, Shimeru

    2012-11-01

    Rapid identification of the causative bacteria of sepsis in patients can contribute to the selection of appropriate antibiotics and improvement of patients' prognosis. Genotypic identification is an emerging technology that may provide an alternative method to, or complement, established phenotypic identification procedures. We evaluated a rapid protocol for bacterial identification based on PCR and pyrosequencing of the V1 and V3 regions of the 16S rRNA gene using DNA extracted directly from positive blood culture samples. One hundred and two positive blood culture bottles from 68 patients were randomly selected and the bacteria were identified by phenotyping and pyrosequencing. The results of pyrosequencing identification displayed 84.3 and 64.7 % concordance with the results of phenotypic identification at the genus and species levels, respectively. In the monomicrobial samples, the concordance between the results of pyrosequencing and phenotypic identification at the genus level was 87.0 %. Pyrosequencing identified one isolate in 60 % of polymicrobial samples, which were confirmed by culture analysis. Of the samples identified by pyrosequencing, 55.7 % showed consistent results in V1 and V3 targeted sequencing; other samples were identified based on the results of V1 (12.5 %) or V3 (31.8 %) sequencing alone. One isolate was erroneously identified by pyrosequencing due to high sequence similarity with another isolate. Pyrosequencing identified one isolate that was not detected by phenotypic identification. The process of pyrosequencing identification can be completed within ~4 h. The information provided by DNA-pyrosequencing for the identification of micro-organisms in positive blood culture bottles is accurate and could prove to be a rapid and useful tool in standard laboratory practice.

  6. Cold-active halophilic bacteria from the ice-sealed Lake Vida, Antarctica.

    Science.gov (United States)

    Mondino, Lindsay J; Asao, Marie; Madigan, Michael T

    2009-10-01

    Lake Vida is a large, permanently ice-covered lake in the Victoria Valley of the McMurdo Dry Valleys, Antarctica and is unique among Dry Valley lakes because it is ice-sealed, with an ice-cover of nearly 19 m. Enrichment cultures of melt-water from Lake Vida 15.9 m ice yielded five pure cultures of aerobic, heterotrophic bacteria. Of these, one strain grew at -8 degrees C and the four others at -4 degrees C. All isolates were either halotolerant or halophilic, with two strains capable of growth at 15% NaCl. Phylogenetic analysis revealed the Lake Vida isolates to be Gammaproteobacteria, related to species of Psychrobacter and Marinobacter. This is the first report of pure cultures of bacteria from Lake Vida, and the isolates displayed a phenotype consistent with life in a cold hypersaline environment.

  7. Detection of Sialic Acid-Utilising Bacteria in a Caecal Community Batch Culture Using RNA-Based Stable Isotope Probing

    Directory of Open Access Journals (Sweden)

    Wayne Young

    2015-03-01

    Full Text Available Sialic acids are monosaccharides typically found on cell surfaces and attached to soluble proteins, or as essential components of ganglioside structures that play a critical role in brain development and neural transmission. Human milk also contains sialic acid conjugated to oligosaccharides, glycolipids, and glycoproteins. These nutrients can reach the large bowel where they may be metabolised by the microbiota. However, little is known about the members of the microbiota involved in this function. To identify intestinal bacteria that utilise sialic acid within a complex intestinal community, we cultured the caecal microbiota from piglets in the presence of 13C-labelled sialic acid. Using RNA-based stable isotope probing, we identified bacteria that consumed 13C-sialic acid by fractionating total RNA in isopycnic buoyant density gradients followed by 16S rRNA gene analysis. Addition of sialic acid caused significant microbial community changes. A relative rise in Prevotella and Lactobacillus species was accompanied by a corresponding reduction in the genera Escherichia/Shigella, Ruminococcus and Eubacterium. Inspection of isotopically labelled RNA sequences suggests that the labelled sialic acid was consumed by a wide range of bacteria. However, species affiliated with the genus Prevotella were clearly identified as the most prolific users, as solely their RNA showed significantly higher relative shares among the most labelled RNA species. Given the relevance of sialic acid in nutrition, this study contributes to a better understanding of their microbial transformation in the intestinal tract with potential implications for human health.

  8. Effects of the probiotic Enterococcus faecium NCIMB 10415 on selected lactic acid bacteria and enterobacteria in co-culture.

    Science.gov (United States)

    Starke, I C; Zentek, J; Vahjen, W

    2015-01-01

    Enterococcus faecium NCIMB 10415 is used as a probiotic for piglets and has been shown to modify the porcine intestinal microbiota. However, the mode of action of this probiotic modification is still unclear. One possible explanation is the direct growth inhibiting or stimulating effect of the probiotic on other indigenous bacteria. Therefore, the aim of the present study was to examine the growth interactions of the probiotic with different indigenous porcine bacteria in vitro. Reference strains were cultivated with the probiotic E. faecium strain NCIMB10415 (SF68) in a checkerboard assay with 102 to 105 cells/ml inoculum per strain. Growth kinetics were recorded for 8 h and used to determine specific growth of the co-cultures. Additionally, total DNA was extracted from the co-cultures at the end of the incubation to verify which strain in the co-culture was affected. Co-cultivation with eight Enterococcus spp. tester strains showed strain-specific growth differences. Three of four E. faecium strains were not influenced by the probiotic strain. PCR results showed reduced growth of the probiotic strain in co-culture with E. faecium DSM 6177. Three of four Enterococcus faecalis strains showed reduced specific growth in co-culture with the probiotic strain. However, E. faecalis DSM 20478 impaired growth of the probiotic E. faecium strain. The growth of Lactobacillus johnsonii DSM 10533 and Lactobacillus reuteri DSM 20016 was enhanced in co-culture with the probiotic strain, but co-cultivations with Lactobacillus mucosae DSM13345 or Lactobacillus amylovorus DSM10533 showed no differences. Co-cultures with the probiotic E. faecium showed no impact on the growth rate of four different enterobacterial reference strains (2 strains of Salmonella enterica and 2 strains of Escherichia coli), but PCR results showed reduced cell numbers for a pathogenic E. coli isolate at higher concentration of the probiotic strain. As the in vitro effect of the probiotic E. faecium on

  9. 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...

  10. Acetic acid bacteria from biofilm of strawberry vinegar visualized by microscopy and detected by complementing culture-dependent and culture-independent techniques.

    Science.gov (United States)

    Valera, Maria José; Torija, Maria Jesús; Mas, Albert; Mateo, Estibaliz

    2015-04-01

    Acetic acid bacteria (AAB) usually develop biofilm on the air-liquid interface of the vinegar elaborated by traditional method. This is the first study in which the AAB microbiota present in a biofilm of vinegar obtained by traditional method was detected by pyrosequencing. Direct genomic DNA extraction from biofilm was set up to obtain suitable quality of DNA to apply in culture-independent molecular techniques. The set of primers and TaqMan--MGB probe designed in this study to enumerate the total AAB population by Real Time--PCR detected between 8 × 10(5) and 1.2 × 10(6) cells/g in the biofilm. Pyrosequencing approach reached up to 10 AAB genera identification. The combination of culture-dependent and culture-independent molecular techniques provided a broader view of AAB microbiota from the strawberry biofilm, which was dominated by Ameyamaea, Gluconacetobacter, and Komagataeibacter genera. Culture-dependent techniques allowed isolating only one genotype, which was assigned into the Ameyamaea genus and which required more analysis for a correct species identification. Furthermore, biofilm visualization by laser confocal microscope and scanning electronic microscope showed different dispositions and cell morphologies in the strawberry vinegar biofilm compared with a grape vinegar biofilm.

  11. Non-culturable Bacteria and Test Methods%活的不可培养细菌及其检测

    Institute of Scientific and Technical Information of China (English)

    刘红; 张明; 姜明洪; 吴光虹

    2015-01-01

    Viable But Non-culturable State(VBNC)is a special condition of the bacteria in the bad environment,but it is difficult or unable to separate culture,and can not detected in this state. It is harm for food safety and public health. Introduction to inducements and recovery conditions ofSalmonella,Staphylococcusaureus,Escherichiacoli,Vibrio parahaemolyticus,Klebsiella peneumoniae, Enterococcus faecal, Vibrio cholerae,Campylobacter jejuni, Shigella bacteria, and current commonly used detection methods of VBNC state of bacteria commonly used detection methods,and current situation of pathogenic microorganisms VBNC in water environment in pathogenic microorganisms and susceptible VBNC in beer VBNC will provide some reference of bacteria in CBNC State for researchers.%活的不可培养(viable but non-culturable state,VBNC)细菌是细菌抵抗恶劣生存环境的一种自我保护形式。细菌在不良环境中,其细胞缩成球形或表现为细胞伸长,体积增大,用常规方法较难或无法进行分离培养,也不能进行检测,但仍具有代谢活性,在一定条件下仍可诱导复苏,具有潜在致病性,给食品安全、公共卫生带来隐患。介绍食品和环境中常见的沙门氏菌、金黄色葡萄球菌、大肠埃希氏菌、副溶血弧菌、肺炎克雷伯氏菌、粪链球菌、霍乱弧菌、空肠弯曲菌、志贺氏菌等细菌的诱导和复苏条件,和目前对VBNC状态细菌常用的检测方法,以及水环境中致病微生物VBNC和啤酒中易感微生物VBNC研究现状,希望能够对细菌VBNC状态的研究者提供一定的参考。

  12. 血培养分离菌的菌谱特征及耐药性分析%Analysis of the Bacteria Spectrum Characteristics and Drug Resistance of Bacteria Isolated from Blood Culture

    Institute of Scientific and Technical Information of China (English)

    李玉梅; 安宏志

    2014-01-01

    Objective To understand the bacteria spectrum characteristics and drug resistance of bacteria isolated from blood cul_ture so as to guide the clinical rational administration. Methods Automated blood culture system Bact/Alert120 and special blood culture bottle were used to culture the bacteria, and the positive specimens were subcultivated to culture media for isolation, iden_tification and drug sensitivity. Results A total of 291 strains of bacteria were isolated from 2370 blood culture specimens, the posi_tive rate was 12.28%. Of the isolated 2 370 strains of bacteria clinically, gram positive bacteria accounted for 71%, gram negative bacteria accounted for 23%, fungi accounted for 1%, other bacteria accounted for 5%. The bacteria ranked the first three were co_agulase negative staphylococcus(45%), Escherichia coli(26%), Staphylococcus aureus(13%). Most gram positive bacteria were high_ly sensitive to vancomycin, no drug-resistant strain occurred;most gram negative bacteria had lowest drug-resistant rate of imipen_em, followed by amikacin. Conclusion The bacteria isolated from blood culture were mainly gram positive bacteria, coagulase neg_ative staphylococcus has high proportion and antibiotic resistance rate. Understanding the distribution and drug resistance of bacte_ria in blood culture is of great importance in reducing bacterial resistance and nosocomial infection and guiding the rational drug use clinically.%目的:了解该院血培养阳性标本中的菌谱分布情况和细菌耐药情况,以指导临床合理用药。方法采用全自动血培养仪Bact/Alert120及专用血培养瓶培养细菌,阳性标本转种至培养基分离﹑鉴定﹑药敏。结果2370份血培养标本共分离到细菌291株,阳性率为12.28%。临床分离的2370株病原菌中,革兰阳性菌占71%,革兰阴性菌占23%,真菌占1%,其他占5%。分离数列前3位的病原菌分别为凝固酶阴性葡萄球菌﹙45%﹚﹑大肠埃希菌﹙26%

  13. Prey-predator dynamics in communities of culturable soil bacteria and protozoa: differential effects of mercury

    DEFF Research Database (Denmark)

    Holtze, M. S.; Ekelund, F.; Rasmussen, Lasse Dam

    2003-01-01

    We investigated whether the prey-predator dynamics of bacteria and protozoa were affected by inorganic mercury at concentrations of 0, 3.5 and 15 mg Hg(II) kg soil(-1). The amount of bioavailable Hg was estimated using a biosensor-assay based on the mer-lux gene fusion. The numbers of bacterial...... with 1/100 TSB as growth medium were also negatively affected by Hg. The different fractions of protozoa were affected to different degrees suggesting that amoebae were less sensitive than slow-growing flagellates, which again were less sensitive than the fast-growing flagellates. In contrast, Hg did...... not induce any detectable changes in the diversity of flagellate morphotypes. In the treatment with 15 mg Hg kg(-1) a transiently increased number of bacteria was seen at day 6 probably concomitant with a decrease in the numbers of protozoa. This might indicate that Hg affected the prey-predator dynamics...

  14. Interspecies interactions result in enhanced biofilm formation by co-cultures of bacteria isolated from a food processing environment.

    Science.gov (United States)

    Røder, Henriette L; Raghupathi, Prem K; Herschend, Jakob; Brejnrod, Asker; Knøchel, Susanne; Sørensen, Søren J; Burmølle, Mette

    2015-10-01

    Bacterial attachment and biofilm formation can lead to poor hygienic conditions in food processing environments. Furthermore, interactions between different bacteria may induce or promote biofilm formation. In this study, we isolated and identified a total of 687 bacterial strains from seven different locations in a meat processing environment and evaluated their biofilm formation capability. A diverse group of bacteria was isolated and most were classified as poor biofilm producers in a Calgary biofilm device assay. Isolates from two sampling sites, the wall and the meat chopper, were further examined for multispecies biofilm formation. Eight strains from each sampling site were chosen and all possible combinations of four member co-cultures were tested for enhanced biofilm formation at 15 °C and 24 °C. In approximately 20% of the multispecies consortia grown at 15 °C, the biofilm formation was enhanced when comparing to monospecies biofilms. Two specific isolates (one from each location) were found to be present in synergistic combinations with higher frequencies than the remaining isolates tested. This data provides insights into the ability of co-localized isolates to influence co-culture biofilm production with high relevance for food safety and food production facilities.

  15. Assessment of rhizospheric culturable bacteria of Phragmites australis and Juncus effusus from polluted sites.

    Science.gov (United States)

    Pereira, Sofia I A; Pires, Carlos; Henriques, Isabel; Correia, António; Magan, Naresh; Castro, Paula M L

    2015-10-01

    This study aimed at the isolation and characterization of metal(loid)-tolerant bacteria from the rhizosphere of Phragmites australis and Juncus effusus plants growing in two long-term contaminated sites in Northern Portugal. Site 1 had higher contamination than Site 3. Bacteria were isolated using metal(loid)-supplemented (Cd, Zn, and As) media. Isolates were grouped by random amplified polymorphic DNA and identified by 16S rRNA gene sequencing. Strains were also examined for their metal(loid) tolerance. The counts of metal(loid)-tolerant bacteria were higher in Site 1 and ranged between log 7.17 CFU g(-1) soil in As-containing medium and log 7.57 CFU g(-1) soil in Zn-containing medium, while counts at Site 3 varied between log 5.33 CFU g(-1) soil in Cd-containing medium and log 6.97 CFU g(-1) soil in As-containing medium. The composition of bacterial populations varied between locations. In Site 1, the classes Actinobacteria (36%) and Bacilli (24%) were well represented, while in Site 3 strains were mainly affiliated to classes Actinobacteria (35%), γ-Proteobacteria (35%), and β-Proteobacteria (12%). The order of metal(loid) toxicity for the isolated strains was Cd > As > Zn. Overall, 10 strains grew at 500 mg Cd L(-1) , 1000 mg Zn L(-1) , and 500 mg As L(-1) , being considered the most metal(loid)-tolerant bacteria. These strains belonged to genera Cupriavidus, Burkholderia, Novosphingobium, Sphingobacterium, Castellaniella, Mesorhizobium, Chryseobacterium, and Rhodococcus and were mainly retrieved from Site 1. The multiple metal(loid)-tolerant strains isolated in this study have potential to be used in bioremediation/phytoremediation.

  16. Growth dynamic of dual culture systems comprising ectomycorrhizal fungi and mycorrhiza helper bacteria

    OpenAIRE

    Sousa, Nadine R.; Ramos, Miguel A.; Castro, Paula M. L.

    2013-01-01

    Ectomycorrhizal fungi are ubiquitous root symbionts that associate with the majority of forest trees and often have a crucial role on plant survival and growth in impoverished soils. Within the vast community of soil microorganisms, the mycorrhiza helper bacteria (MHB) are recognizably one of the groups that most directly affect fungal growth and mycorrhiza establishment. Although their positive effect on the mycorrhizal partnership has been previously reported, the specificity of such associ...

  17. Targeting motility properties of bacteria in the development of probiotic cultures against Campylobacter jejuni in broiler chickens.

    Science.gov (United States)

    Aguiar, Vivian F; Donoghue, Ann M; Arsi, Komala; Reyes-Herrera, Ixchel; Metcalf, Joel H; de los Santos, Fausto S; Blore, Pamela J; Donoghue, Dan J

    2013-05-01

    Campylobacter is the leading cause of gastroenteritis worldwide. Campylobacter is commonly present in the intestinal tract of poultry, and one strategy to reduce enteric colonization is the use of probiotic cultures. This strategy has successfully reduced enteric colonization of Salmonella, but has had limited success against Campylobacter. In an effort to improve the efficacy of probiotic cultures, we developed a novel in vitro screening technique for selecting bacterial isolates with enhanced motility. It is proposed that motility-selected bacteria have the marked ability to reach the same gastrointestinal niche in poultry and competitively reduce C. jejuni. Bacterial isolates were collected from ceca of healthy chickens, and motile isolates were identified and tested for anti-Campylobacter activity. Isolates with these properties were selected for increased motility by passing each isolate 10 times and at each passage selecting bacteria that migrated the farthest during each passage. Three bacterial isolates with the greatest motility (all Bacillus subtilis) were used alone or in combination in two chicken trials. At day of hatch, chicks were administered these isolates alone or in combination (n=10/treatment, two trials), and chicks were orally challenged with a mixture of four different wild-type strains of C. jejuni (∼10(5) CFU/mL) on day 7. Isolate 1 reduced C. jejuni colonization in both of the trials (pchickens dosed using isolate with enhanced motility compared to the control and unselected isolate. These findings support the theory that the motility enhancement of potential probiotic bacteria may provide a strategy for reduction of C. jejuni in preharvest chickens.

  18. Use of Bacteriocinogenic Cultures without Inhibiting Cheese Associated Nonstarter Lactic Acid Bacteria; A Trial with Lactobacillus plantarum

    Directory of Open Access Journals (Sweden)

    Franca Rossi

    2016-02-01

    Full Text Available Bacteriocinogenic cultures can represent a natural way to increase the safety of cheeses made from raw milk, in which a relevant role in ripening and flavor formation is exerted by the nonstarter lactic acid bacteria (NSLAB. Since the latter can be inhibited by bacteriocin producers, this study evaluated to which extent a nisinogenic culture inoculated at low initial levels can affect the growth rate and peptide degradation activity of the nisin-sensitive cheese isolate Lactobacillus plantarum LZ by comparison with its isogenic variant, L. plantarum LZNI, with increased immunity to nisin. A growth delay of the nisin sensitive strain was observed only when its initial number was 100-fold lower than the nisin producer and nisin was added as an inducer of its own production. In this case, the amount of free α-amino groups was significantly different between cultures of L. plantarum LZ and LZNI only at Day 1. Reverse Phase High Performance Liquid Chromatography (RP-HPLC highlighted a few differences between the peptide profiles of co-cultures L. plantarum LZ and LZNI. However, results showed that the bacteriocin producer did not dramatically influence the behavior of the sensitive NSLAB and that the evaluation of the effects on microbial contaminants in cheese is worthwhile.

  19. The Use of Lactic Acid Bacteria Starter Culture in the Production of Nunu, a Spontaneously Fermented Milk Product in Ghana

    Directory of Open Access Journals (Sweden)

    Fortune Akabanda

    2014-01-01

    Full Text Available Nunu, a spontaneously fermented yoghurt-like product, is produced and consumed in parts of West Africa. A total of 373 predominant lactic acid bacteria (LAB previously isolated and identified from Nunu product were assessed in vitro for their technological properties (acidification, exopolysaccharides production, lipolysis, proteolysis and antimicrobial activities. Following the determination of technological properties, Lactobacillus fermentum 22-16, Lactobacillus plantarum 8-2, Lactobacillus helveticus 22-7, and Leuconostoc mesenteroides 14-11 were used as single and combined starter cultures for Nunu fermentation. Starter culture fermented Nunu samples were assessed for amino acids profile and rate of acidification and were subsequently evaluated for consumer acceptability. For acidification properties, 82%, 59%, 34%, and 20% of strains belonging to Lactobacillus helveticus, L. plantarum, L. fermentum, and Leu. mesenteriodes, respectively, demonstrated fast acidification properties. High proteolytic activity (>100 to 150 μg/mL was observed for 50% Leu. mesenteroides, 40% L. fermentum, 41% L. helveticus, 27% L. plantarum, and 10% Ent. faecium species. In starter culture fermented Nunu samples, all amino acids determined were detected in Nunu fermented with single starters of L. plantarum and L. helveticus and combined starter of L. fermntum and L. helveticus. Consumer sensory analysis showed varying degrees of acceptability for Nunu fermented with the different starter cultures.

  20. Clinical identification of bacteria in human chronic wound infections: culturing vs. 16S ribosomal DNA sequencing

    OpenAIRE

    Rhoads Daniel D; Cox Stephen B; Rees Eric J; Sun Yan; Wolcott Randall D

    2012-01-01

    Abstract Background Chronic wounds affect millions of people and cost billions of dollars in the United States each year. These wounds harbor polymicrobial biofilm communities, which can be difficult to elucidate using culturing methods. Clinical molecular microbiological methods are increasingly being employed to investigate the microbiota of chronic infections, including wounds, as part of standard patient care. However, molecular testing is more sensitive than culturing, which results in m...

  1. Variation of correlations between factors and culturable airborne bacteria and fungi

    Science.gov (United States)

    Gao, Min; Yan, Xu; Qiu, Tianlei; Han, Meilin; Wang, Xuming

    2016-03-01

    Bioaerosols, including their characteristics and overall changes correlated with environmental factors, have the potential to impact human health and influence atmospheric dynamics. In this study, the varying interrelationship between the concentration and diameter of culturable bioaerosols and twelve factors including PM2.5 (AQI), PM10 (AQI), sampling time, sampling season, temperature, relative humidity, dew, pressure, wind, O3, NO2, and SO2 is determined for twelve months during non-haze and haze days in Beijing. Results of principal component analysis (PCA) indicated that the influence of factors on culturable bioaerosols is mainly associated with haze levels, sampling time, and season. Multiple linear regressions showed that the correlation between PM10 (AQI) or temperature and culturable bioaerosols varied at different haze levels. The seasonal influence of PM2.5 (AQI) was observed in culturable bioaerosol concentrations, but not their diameters. A temporal relationship between PM10 (AQI) and culturable bioaerosol concentration was detected during rush hour. SO2 and NO2 show positive and negative correlations with culturable bioaerosol concentrations in the morning/evening and mid-day, respectively. These results are useful for accurately evaluating the health effects of exposure to bioaerosols.

  2. Taxonomic status and ecologic function of methanogenic bacteria isolated from the oral cavity of humans

    Energy Technology Data Exchange (ETDEWEB)

    Kemp, C.W.

    1985-01-01

    The detection of methane gas in samples of dental plaque and media inoculated with dental plaque was attributed to the presence of methane-producing bacteria in the plaque microbiota. The results of a taxonomic analysis of the 12 methanogenic isolates obtained from human dental plaque, (ABK1-ABK12), placed the organisms in the genus Methanobrevibacter. A DNA-DNA hybridization survey established three distinct genetic groups of oral methanogens based on percent homology values. The groups exhibited less than 32% homology between themselves and less than 17% homology with the three known members of the genus methanobrevibacter. The ecological role of the oral methanogens was established using mixed cultures of selected methanogenic isolates (ABK1, ABK4, ABK6, or ABK7) with oral heterotrophic bacteria. Binary cultures of either Streptococcus mutans, Streptococcus sanguis, Veillonella rodentium, Lactobacillus casei, or Peptostreptococcus anaerobius together with either methanogenic isolates ABK6 or ABK7 were grown to determine the effect of the methanogens on the distribution of carbon end products produced by the heterotrophs. Binary cultures of S. mutans and ABK7 exhibited a 27% decrease in lactic acid formation when compared to pure culture of S. mutans. The decrease in lactic acid production was attributed to the removal of formate by the methanogen, (ABK7), which caused an alteration in the distribution of carbon end products by S. mutans.

  3. Effects of carbon source on nitrogen removal of heterotrophic nitrifying and aerobic denitrifying bacteria strain qy37%包埋异养硝化好氧反硝化菌株qy37脱氮效果的碳源选择

    Institute of Scientific and Technical Information of China (English)

    张培玉; 张晨; 孙梦; 吴玉光

    2011-01-01

    This paper is concerned about the influence of the carbon source on the nitrogen removing rate in case of the heterotrophic nitrifying and aerobic denitrifying bacteria strain qy37. As is known, carbon source and its concentration may have significant effects on the bio-denitrification process. To solve the problem of low nitrogen removing rate due to the shortage of organic carbon, we have made thorough revision of the advances made in the world in recent years and explored the related mechanisms and factors affecting denitrifica-tion along with the analysis of the carbon source choice. Furthermore, we have conducted experiments in testing the potential of immobilized denitrifier of a strain coded as qy37 so as to reduce the nitrate at the presence of five different carbon sources, namely, lactose, sodium citrate, soluble starch, cane sugar and glucose. According to the features of carbon source and the potential influence on the water denitri-fication, we have chosen soluble starch as an available plant carbon source. The results of our study show the order of the nitrogen removal rate turns to be as follows: soluble starch > glucose > cane sugar > sodium citrate > lactose, of which soluble starch comes first. It has also been found that nitrogen removal rate can be made as high as above 85% . Right amount of soluble starch added helps to improve the removing rate while enhancing the mechanical strength of sodium alga acid and PVA ball, reducing the adsorption of PVA and water swelling simultaneously. Besides, the most appropriate concentration of the nitrogen removal has been found by changing different concentrations of the carbon source, for example, concentrations of 3 g/L, 5 g/L, 8 g/L, 10 g/L with soluble starch as carbon source. The results of our study indicate that the optimal concentration of carbon sources should be 8 g/L. Besides, we have also studied the method of embedding carbon source, that is, the denitrification rate by embedding carbon

  4. Diversity of thermophilic bacteria in raw, pasteurized and selectively-cultured milk, as assessed by culturing, PCR-DGGE and pyrosequencing.

    Science.gov (United States)

    Delgado, Susana; Rachid, Caio T C C; Fernández, Elena; Rychlik, Tomasz; Alegría, Angel; Peixoto, Raquel S; Mayo, Baltasar

    2013-10-01

    Thermophilic lactic acid bacteria (LAB) species, such as Streptococcus thermophilus, Lactobacillus delbrueckii and Lactobacillus helveticus, enjoy worldwide economic importance as dairy starters. To assess the diversity of thermophilic bacteria in milk, milk samples were enriched in thermophilic organisms through a stepwise procedure which included pasteurization of milk at 63 °C for 30 min (PM samples) and pasteurization followed by incubation at 42 °C for 24 h (IPM samples). The microbial composition of these samples was analyzed by culture-dependent (at 42 °C) and culture-independent (PCR-DGGE and pyrosequencing of 16S rRNA gene amplicons) microbial techniques. The results were then compared to those obtained for their corresponding starting raw milk counterparts (RM samples). Twenty different species were scored by culturing among 352 isolates purified from the counting plates and identified by molecular methods. Mesophilic LAB species (Lactococcus lactis, Lactococcus garvieae) were dominant (87% of the isolates) among the RM samples. However, S. thermophilus and Lb. delbrueckii were found to be the dominant recoverable organisms in both PM and IPM samples. The DGGE profiles of RM and PM samples were found to be very similar; the most prominent bands belonging to Lactococcus, Leuconostoc and Streptococcus species. In contrast, just three DGGE bands were obtained for IPM samples, two of which were assigned to S. thermophilus. The pyrosequencing results scored 95 operational taxonomic units (OTUs) at 3% sequence divergence in an RM sample, while only 13 were encountered in two IPM samples. This technique identified Leuconostoc citreum as the dominant microorganism in the RM sample, while S. thermophilus constituted more than 98% of the reads in the IPM samples. The procedure followed in this study allowed to estimate the bacterial diversity in milk and afford a suitable strategy for the isolation of new thermophilic LAB strains, among which adequate

  5. The Metabolic Response of Arabidopsis Roots to Oxidative Stress is Distinct from that of Heterotrophic Cells in Culture and Highlights a Complex Relationship between the Levels of Transcripts,Metabolites,and Flux

    Institute of Scientific and Technical Information of China (English)

    Martin Lehmann; Markus Schwarzl(a)inder; Toshihiro Obata; Supaart Sirikantaramas; Meike Burow; Carl Erik Olsen; Takayuki Tohge; Mark D.Fricker; Birger Lindberg Mφller; Alisdair R.Fernie; Lee J.Sweetloveb; Miriam Laxa

    2009-01-01

    Metabolic adjustments are a significant,but poorly understood,part of the response of plants to oxidative stress.In a previous study (Baxter et al.,2007),the metabolic response of Arabidopsis cells in culture to induction of ox-idative stress by menadione was characterized.An emergency survival strategy was uncovered in which anabolic primary metabolism was largely down-regulated in favour of catabolic and antioxidant metabolism.The response in whole plant tissues may be different and we have therefore investigated the response of Arabidopsis roots to menadione treatment,analyzing the transcriptome,metabolome and key metabolic fluxes with focus on primary as well as secondary metab-olism.Using a redox-sensitive GFP,it was also shown that menadione causes redox perturbation,not just in the mitochon-drion,but also in the cytosol and plastids of roots.In the first 30 min of treatment,the response was similar to the cell culture:there was a decrease in metabolites of the TCA cycle and amino acid biosynthesis and the transcriptomic response was dominated by up-regulation of DNA regulatory proteins.After 2 and 6 h of treatment,the response of the roots was different to the cell culture.Metabolite levels did not remain depressed,but instead recovered and,in the case of pyruvate,some amino acids and aliphatic glucosinolates showed a steady increase above control levels.However,no major changes in fluxes of central carbon metabolism were observed and metabolic transcripts changed largely independently of the corresponding metabolites.Together,the results suggest that root tissues can recover metabolic activity after oxidative inhibition and highlight potentially important roles for glycolysis and the oxidative pentose phosphate pathway.

  6. Antimicrobial activity of heterotrophic bacterial communities from the marine sponge Erylus discophorus (Astrophorida, Geodiidae.

    Directory of Open Access Journals (Sweden)

    Ana Patrícia Graça

    Full Text Available Heterotrophic bacteria associated with two specimens of the marine sponge Erylus discophorus were screened for their capacity to produce bioactive compounds against a panel of human pathogens (Staphylococcus aureus wild type and methicillin-resistant S. aureus (MRSA, Bacillus subtilis, Pseudomonas aeruginosa, Acinetobacter baumanii, Candida albicans and Aspergillus fumigatus, fish pathogen (Aliivibrio fischeri and environmentally relevant bacteria (Vibrio harveyi. The sponges were collected in Berlengas Islands, Portugal. Of the 212 isolated heterotrophic bacteria belonging to Alpha- and Gammaproteobacteria, Actinobacteria and Firmicutes, 31% produced antimicrobial metabolites. Bioactivity was found against both Gram positive and Gram negative and clinically and environmentally relevant target microorganisms. Bioactivity was found mainly against B. subtilis and some bioactivity against S. aureus MRSA, V. harveyi and A. fisheri. No antifungal activity was detected. The three most bioactive genera were Pseudovibrio (47.0%, Vibrio (22.7% and Bacillus (7.6%. Other less bioactive genera were Labrenzia, Acinetobacter, Microbulbifer, Pseudomonas, Gordonia, Microbacterium, Micrococcus and Mycobacterium, Paenibacillus and Staphylococcus. The search of polyketide I synthases (PKS-I and nonribosomal peptide synthetases (NRPSs genes in 59 of the bioactive bacteria suggested the presence of PKS-I in 12 strains, NRPS in 3 strains and both genes in 3 strains. Our results show the potential of the bacterial community associated with Erylus discophorus sponges as producers of bioactive compounds.

  7. Nitrate concentration-shift cultivation to enhance protein content of heterotrophic microalga Chlorella vulgaris: Over-compensation strategy.

    Science.gov (United States)

    Xie, Tonghui; Xia, Yun; Zeng, Yu; Li, Xingrui; Zhang, Yongkui

    2017-02-27

    Protein production from microalgae requires both high cell density during cultivation and high protein content in cells. Heterotrophic microalgae can achieve high cell density, and yet are confronted with the problem of low protein content. Based on over-compensation strategy, a new concentration-shift method was proposed to cultivate heterotrophic Chlorella vulgaris, aiming to increase protein content. With a prior starvation period, microalgae utilized more nitrate and accumulated more proteins compared to one-stage cultivation. Considering the convenience of operation, nitrate-added culture was adopted for producing heterotrophic microalgae, rather than sterile centrifugal culture. Operating parameters including nitrate concentration in N-deficient medium, N-starved time and nitrate concentration in N-rich medium were optimized, which were 0.18gl(-1), 38h and 2.45gl(-1), respectively. Under the optimized conditions, protein content in heterotrophic Chlorella reached 44.3%. Furthermore, the heterotrophic microalga was suggested to be a potential single-cell protein source according to the amino acid composition.

  8. Chromium induced stress conditions in heterotrophic and auxotrophic strains of Euglena gracilis.

    Science.gov (United States)

    Rocchetta, Iara; Mazzuca, Marcia; Conforti, Visitación; Balzaretti, Vilma; del Carmen Ríos de Molina, María

    2012-10-01

    Oxidative stress parameter and antioxidant defense compound as well as enzyme activity were studied in relation to different Cr(VI) concentrations (0, 10, 20, 40 μM) in two strains of Euglena gracilis, one isolated from a polluted river (MAT) and the other acquired from a culture collection (UTEX). Chromium toxicity was measured in the auxotrophic and obligated heterotrophic variants of the two strains. Chromium uptake was higher in auxotrophic cultures, reflected by their higher cell proliferation inhibition and lower IC50 levels compared to heterotrophic ones. In the Cr(VI) treatments a reduction of chlorophyll a and b ratio (Chl a/Chl b) was observed, the ratio of protein to paramylon content was augmented, and total lipid content increased, having the auxotrophic strains the highest values. TBARS content increased significantly only at 40 μM Cr(VI) treatment. Unsaturated fatty acids also increased in the Cr(VI) treatments, with the higher storage lipid (saturated acids) content in the heterotrophic cells. The antioxidant response, such as SOD activity and GSH content, increased with chromium concentration, showing the highest GSH values in the heterotrophic cultures and the SOD enzyme participation in chromium toxicity. The MAT strain had higher IC50 values, higher carbohydrate and saturated acid content, and better response of the antioxidant system than the UTEX one. This strain isolated from the polluted place also showed higher GSH content and SOD activity in control cells and in almost all treated cultures. SOD activity reached a 9-fold increase in both MAT strains. These results suggest that tolerance of MAT strain against Cr(VI) stress is not only related to GSH level and/or biosynthesis capacity but is also related to the participation of the SOD antioxidant enzyme.

  9. A culture-dependent survey of thermophilic bacteria from hot springs in Xiamen area in China

    Institute of Scientific and Technical Information of China (English)

    YANG Bo; OUYANG Jianping; AO Jingqun; CHEN Xinhua

    2009-01-01

    Microbes are believed to play important roles in ecosystem function in many environments. The hot springs of Xiamen Island are close to the Xiamen Sea, and may have some characteristics different from those of inland hot springs. Microbes living in the hot springs of Xiamen may have new characteristics. However, little is known about microbial communities of hot springs close to the Xiamen Sea. A cuhure-dependent survey of microbial population in the Xiamen hot springs was pcrformed by using an approach combining total cellular protein profile identification and 16S rRNA gene sequencing. A total of 328 isolates of bacteria were obtained from liquid and sediment samples from the Xiamen hot springs, including neutrophilie thermophilic bacteria and moderately thermophilic acidophiles. Neutrophilic thermophilic bacteria, which grow at a temperature range of 55-90℃ including Rhodothermus marinus (Strain 1) , Thermus thermophilus (Strain 2), Thermus thiopara (Strain 3) , Geobacillus stearothermophilus(Strain 4) , Geobacillus thermoleovorans (Strain 5) , and Pseudomonas pseudoal-caligenes (Strain 6), were recovered by 2216E plates. Moderately thermophilic acidophiles, which can grow at temperatures above 50℃ and a pH range of 1. 8-3.5 such as Alicyclobacillus acidoterrestris (Strain 8) , Sul-fobacillus acidophilus (Strain 9), and Sulfobacillus thermosulfidooxidans (Strain 10), were isolated on selective solid medium containing sulfur and Fe2+. Among these strains, Rhodothermus marinus, Thermus thermophilus and Geobacillus stearothermophilus are not only thermophilcs, but also halophiles. One bacterium strain (Strain 6) shared 99% nucleotide sequence homology with Pseudomonas pseudoalcaligenes on the 16S rRNA gene se-quence, but was quite different from Pseudomonas pseudoalcaligenes in biological characteristics, suggesting that it may represent a novel thermophilic species. Results indicated that various species of neutrophilic thermophiles and moderately thermophilic

  10. BIOLOGICAL NITROGEN REMOVAL FROM WASTEWATER BY DENITRIFICATION OF MIX-CULTURING FUNGI AND BACTERIA

    Institute of Scientific and Technical Information of China (English)

    TAKAYA; Naoki; SHOUN; Hirofumi

    2006-01-01

    Denitrificationis a biological processin which nitrateand/or nitrite is reduced to gaseous nitrogen,dinitrogen(N2)or nitrous oxide(N2O)while carbon dioxide is thesecond gaseous product of the process.This is one of themain mechanisms of the global nitrogen cycle,and playsanimportant role as the reverse reaction of nitrogen fixa-tion in maintaining global environmental homeostasis[1].Denitrification has beenlongthought to be a unique char-acteristic of prokaryotes[2,3].Anumber of bacteria(suchasPseudomonas s...

  11. Identification of triclosan-degrading bacteria in a triclosan enrichment culture using stable isotope probing.

    Science.gov (United States)

    Lee, Do Gyun; Cho, Kun-Ching; Chu, Kung-Hui

    2014-02-01

    Triclosan, a widely used antimicrobial agent, is an emerging contaminant in the environment. Despite its antimicrobial character, biodegradation of triclosan has been observed in pure cultures, soils and activated sludge. However, little is known about the microorganisms responsible for the degradation in mixed cultures. In this study, active triclosan degraders in a triclosan-degrading enrichment culture were identified using stable isotope probing (SIP) with universally (13)C-labeled triclosan. Eleven clones contributed from active microorganisms capable of uptake the (13)C in triclosan were identified. None of these clones were similar to known triclosan-degraders/utilizers. These clones distributed among α-, β-, or γ-Proteobacteria: one belonging to Defluvibacter (α-Proteobacteria), seven belonging to Alicycliphilus (β-Proteobacteria), and three belonging to Stenotrophomonas (γ-Proteobacteria). Successive additions of triclosan caused a significant shift in the microbial community structure of the enrichment culture, with dominant ribotypes belonging to the genera Alicycliphilus and Defluvibacter. Application of SIP has successfully identified diverse uncultivable triclosan-degrading microorganisms in an activated sludge enrichment culture. The results of this study not only contributed to our understanding of the microbial ecology of triclosan biodegradation in wastewater, but also suggested that triclosan degraders are more phylogenetically diverse than previously reported.

  12. Identification and Antimicrobial Resistance of Bacteria Isolated from Probiotic Products Used in Shrimp Culture

    DEFF Research Database (Denmark)

    Noor Uddin, Gazi Md; Larsen, Marianne Halberg; Christensen, Henrik;

    2015-01-01

    in aquaculture ponds. Concerns have been raised that the declared information on probiotic product labels are incorrect and information on bacterial composition are often missing. We therefore evaluated seven probiotics commonly used in Vietnamese shrimp culture for their bacterial species content, phenotypic...... that they contained macrolide (ermD), tetracycline (tetL), phenicol (fexA) and trimethoprim (dfrD, dfrG and dfrK) resistance genes, but not known structures associated with horizontal gene transfer. Probiotic bacterial strains used in Vietnamese shrimp culture seem to contribute with very limited types and numbers....... used to identify resistance genes and genetic elements associated with horizontal gene transfer. Thirteen bacterial species declared on the probiotic products could not be identified and 11 non-declared Bacillus spp. were identified. Although our culture-based isolation and identification may have...

  13. Diversity of bacteria and archaea from a landfill in Chandigarh, India as revealed by culture-dependent and culture-independent molecular approaches.

    Science.gov (United States)

    Krishnamurthi, S; Chakrabarti, T

    2013-02-01

    The bacterial community structure of a municipal landfill in Chandigarh, India was analysed by culture-dependent as well as culture-independent molecular approaches, and archaeal structure by the latter method. Samples were collected in two phases from the surface and a depth of 0.91 m in June, 2004 and from 0.91 m, 1.52 m and 1.68 m in May, 2005. After serial dilutions, samples were plated onto tryptic soy agar (TSA), plate count agar (PCA), tryptic soy broth agar (TSBA) and TSBA100 (TSBA diluted 100 times and solidified with agarose), and incubated aerobically at 30°C. The number of bacteria (CFU) on different media ranged between 9.4×10⁵g⁻¹ (on PCA) and 1.9×10⁷g⁻¹ (on TSA) (wet weight). The numbers of bacteria enumerated from plates incubated anaerobically (anaerobic agar and reinforced clostridial agar) were 2.1×10⁷and 1.7×10⁶g⁻¹, respectively. Of the 468 isolated and purified bacteria (183 in the first phase and 285 in the second phase), 135 were characterised using phenotypic characteristics as well as 16S rRNA gene sequence analysis. It was found that members of the phylum Firmicutes were overwhelmingly predominant (86.6%) in the landfill, followed by Actinobacteria (9.6%) and Proteobacteria (3.7%). Among the Firmicutes, at least 17 species from the single genus Bacillus were the most abundant inhabitants of the landfill. Detailed polyphasic characterisation of many of these isolates led to the discovery of a novel genus Paenisporosarcina (and the species P. quisquiliarum), a novel species of Microbacterium, M. immunditiarum, and reclassification of Sporosarcina macmurdoensis, Pelagibacillus goriensis, Bacillus silvestris, Bacillus insolitus, Bacillus psychrotolerans and Bacillus psychrodurans. Culture-independent analysis of two 16S rRNA gene libraries also revealed that the phylum Firmicutes was the predominant group in this community. The diversity of Archaea was found to be limited mainly to members of two orders: Methanosarcinales

  14. Phylogenetically distinct bacteria involve extensive dechlorination of aroclor 1260 in sediment-free cultures.

    Directory of Open Access Journals (Sweden)

    Shanquan Wang

    Full Text Available Microbial reductive dechlorination of the persistent polychlorinated biphenyls (PCBs is attracting much attention in cleanup of the contaminated environment. Nevertheless, most PCB dechlorinating cultures require presence of sediment or sediment substitutes to maintain their dechlorination activities which hinders subsequent bacterial enrichment and isolation processes. The information on enriching sediment-free PCB dechlorinating cultures is still limited. In this study, 18 microcosms established with soils and sediments were screened for their dechlorination activities on a PCB mixture - Aroclor 1260. After one year of incubation, 10 out of 18 microcosms showed significant PCB dechlorination with distinct dechlorination patterns (e.g., Process H, N and T classified based on profiles of PCB congeners loss and new congeners formation. Through serial transfers in defined medium, six sediment-free PCB dechlorinating cultures (i.e., CW-4, CG-1, CG-3, CG-4, CG-5 and SG-1 were obtained without amending any sediment or sediment-substitutes. PCB dechlorination Process H was the most frequently observed dechlorination pattern, which was found in four sediment-free cultures (CW-4, CG-3, CG-4 and SG-1. Sediment-free culture CG-5 showed the most extensive PCB dechlorination among the six cultures, which was mediated by Process N, resulting in the accumulation of penta- (e.g., 236-24-CB and tetra-chlorobiphenyls (tetra-CBs (e.g., 24-24-CB, 24-25-CB, 24-26-CB and 25-26-CB via dechlorinating 30.44% hepta-CBs and 59.12% hexa-CBs after three months of incubation. For culture CG-1, dechlorinators mainly attacked double flanked meta-chlorines and partially ortho-chlorines, which might represent a novel dechlorination pattern. Phylogenetic analysis showed distinct affiliation of PCB dechlorinators in the microcosms, including Dehalogenimonas and Dehalococcoides species. This study broadens our knowledge in microbial reductive dechlorination of PCBs, and provides

  15. [Actinomyces and other bacteria isolated from cervical cultures of women using IUDs].

    Science.gov (United States)

    Güleç, N; Günalp, A

    1987-07-01

    In this study we performed endocervical cultures from 517 patients with infection. In 75 of these 517 cultures (14.5%) Actinomyces has been grown. The incidence of Actinomyces has increased in correlation with IUD period, but the type of IUD has not affected the incidence of Actinomyces. Actinomycosis of uterus is usually superficial. It rarely spreads and causes pelvic actinomycosis. Even it can change to systemic infection. For this reason, in women who have used IUDs for long period Actinomyces infection should be kept in mind. Clinicians should be in corporation with the laboratories, this is important for identification of the microorganism and for the right therapy.

  16. Population dynamics of mixed cultures of yeast and lactic acid bacteria in cider conditions

    Directory of Open Access Journals (Sweden)

    Leila Roseli Dierings

    2013-10-01

    Full Text Available The objective of this work was to study the malolactic bioconversion in low acidity cider, according Brazilian conditions. The apple must was inoculated with Saccharomyces cerevisiae or S. cerevisiae with Oenococcus oeni. The control contained the indigenous microorganisms. Fermentation assays were carried out with clarified apple must from the Gala variety. At the beginning of fermentation, there was a fast growth of the non-Saccharomyces yeast population. Competitive inhibition occurred in all the assays, either with inoculated or indigenous populations of the yeast. The lactic acid bacteria count was ca. 1.41·10²CFU/mL at the beginning and 10(6CFU/mL after yeast cells autolysis. The lactic bacteria O. oeni reached the highest population (10(7CFU/mL when added to the apple must after the decline of the yeast. The malic acid was totally consumed during the alcoholic fermentation period (80.0 to 95.5 % and lactic acid was still synthesized during the 35 days of malolactic fermentation. These results could be important in order to achieve a high quality brut, or sec cider obtained from the dessert apple must.

  17. Marine Bacteria with antimicrobials capacity isolated from cultures of bivalve mollusks

    Directory of Open Access Journals (Sweden)

    Fabiola Pellon

    2014-06-01

    Full Text Available Microorganisms have commonly been studied as producers of antibacterial substances; yet they are also considered producers of antifungic, antiviral, antiparasitic, citotoxics and inhibitory of other forms of cellular growth substances. This paper describes the isolation, inhibitory potential and phenotipic characterization of native bacterial strains associated to bivalve mollusks such as Argopecten purpuratus “concha de abanico” and Crassostrea gigas “ostra” in cultivation systems. From 345 marine strains collected, 20 strains were recovered that had the ability of inhibiting a wide spectrum of fish, mollusks and shellfish pathogenic bacteria; being the most sensitive pathogens Aeromonas sobria P-281, Aeromonas hydrophila ATCC 7966, Vibrio vulnificus ATCC 27562 and Vibrio parahaemolyticus ATCC 17803. The phenotipic characterization of this strains with inhibitory capacity allowed the identification of the following genera: Vibrio (40%, Aeromonas (15%, Flavobacterium (10%, Pseudomonas (5%, Moraxella (5%, Flexibacter (5%. A 20% could not be identified. The results suggest that the isolated bacteria could be used as probiotics agents for the biological control of pathogens from marine organisms of interest in mariculture.

  18. Growth of Dunaliella tertiolecta and associated bacteria in photobioreactors.

    Science.gov (United States)

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

    2012-09-01

    The aim of this study was to test three flat-plate photobioreactor configurations for cultivation of marine green alga Dunaliella tertiolecta under non-axenic growth conditions and to characterize and quantify the associated bacteria. The photobioreactor cultivations were conducted using tap water-based media. Static mixers intended to enhance mixing and light utilization did not generally increase algal growth at the low light intensities used. The maximum biomass concentration (measured as volatile suspended solids) and maximum specific growth rate achieved in the flat plate with no mixer were 2.9 g l⁻¹ and 1.3 day⁻¹, respectively. Based on quantitative polymerase chain reaction, bacterial growth followed the growth of D. tertiolecta. Based on 16S rDNA amplification and denaturing gradient gel electrophoresis profiling, heterotrophic bacteria in the D. tertiolecta cultures mainly originated from the non-axenic algal inocula, and tap water heterotrophs were not enriched in high chloride media (3 % salinity). Bacterial communities were relatively stable and reproducible in all flat-plate cultivations and were dominated by Gammaproteobacteria, Flavobacteria, and Alphaproteobacteria.

  19. The prevalence of overgrowth by aerobic bacteria in the small intestine by small bowel culture: relationship with irritable bowel syndrome.

    Science.gov (United States)

    Pyleris, Emmannouil; Giamarellos-Bourboulis, Evangelos J; Tzivras, Dimitrios; Koussoulas, Vassilios; Barbatzas, Charalambos; Pimentel, Mark

    2012-05-01

    Many studies have linked irritable bowel syndrome (IBS) with small intestinal bacterial overgrowth (SIBO), although they have done so on a qualitative basis using breath tests even though quantitative cultures are the hallmark of diagnosis. The purpose of this study was to underscore the frequency of SIBO in a large number of Greeks necessitating upper gastrointestinal (GI) tract endoscopy by using quantitative microbiological assessment of the duodenal aspirate. Consecutive subjects presenting for upper GI endoscopy were eligible to participate. Quantitative culture of aspirates sampled from the third part of the duodenum during upper GI tract endoscopy was conducted under aerobic conditions. IBS was defined by Rome II criteria. Among 320 subjects enrolled, SIBO was diagnosed in 62 (19.4%); 42 of 62 had IBS (67.7%). SIBO was found in 37.5% of IBS sufferers. SIBO was found in 60% of IBS patients with predominant diarrhea compared with 27.3% without diarrhea (P = 0.004). Escherichia coli, Enterococcus spp and Klebsiella pneumoniae were the most common isolates within patients with SIBO. A step-wise logistic regression analysis revealed that IBS, history of type 2 diabetes mellitus and intake of proton pump inhibitors were independently and positively linked with SIBO; gastritis was protective against SIBO. Using culture of the small bowel, SIBO by aerobe bacteria is independently linked with IBS. These results reinforce results of clinical trials evidencing a therapeutic role of non-absorbable antibiotics for the management of IBS symptoms.

  20. Antibiotic Resistance and Heavy Metals Tolerance in Gram-Negative Bacteria from Diseased American Bullfrog (Rana catesbeiana) Cultured in Malaysia

    Institute of Scientific and Technical Information of China (English)

    M Na-jian; S W Lee; W Wendy; L W Tee; M Nadirah; S H Faizah

    2009-01-01

    A total of 140 bacterial isolates have been successfully isolated from various organs of diseased American bullfrog (Rana catesbeiana) cultured in Malaysia. The most frequently isolated bacteria was Edwardsiella spp. (46 isolates) followed by Aeromonas spp. (33 isolates), Flavobacterium spp. (31 isolates), and Vibrio spp. (30 isolates). Majority of the bacterial isolates were found sensitive to furazolidone (85.0%), chloramphenicol (85.0%), oxolinic acid (90.0%), florfenicol (95.0%), and flumequine (97.5%). On the other hand, most of the bacterial isolates were resistant to oleandomycin (77.5%) and lincomycin (87.5%). Nitrofurantoin and flumequine can be inhibited the growth of all of Vibrio spp. whereas all isolates of Edwardsiella spp. were found sensitive to florfenicol and flumequine. Multiple antibiotic resistance (MAR) index were in range of 0.30-0.40, indicating that bacterial isolates from cultured bullfrogs may have received high risk exposure to the tested antibiotics. In addition, 90-100% of the isolates were resistant to copper, cadmium, and chromium. These results provided insight information on tolerance level of bacterial isolates from cultured bullfrogs to 21 antibiotics as well as heavy metals.

  1. Miniaturized extinction culturing is the preferred strategy for rapid isolation of fast-growing methane-oxidizing bacteria.

    Science.gov (United States)

    Hoefman, Sven; van der Ha, David; De Vos, Paul; Boon, Nico; Heylen, Kim

    2012-05-01

    Methane-oxidizing bacteria (MOB) have a large potential as a microbial sink for the greenhouse gas methane as well as for biotechnological purposes. However, their application in biotechnology has so far been hampered, in part due to the relative slow growth rate of the available strains. To enable the availability of novel strains, this study compares the isolation of MOB by conventional dilution plating with miniaturized extinction culturing, both performed after an initial enrichment step. The extinction approach rendered 22 MOB isolates from four environmental samples, while no MOB could be isolated by plating. In most cases, extinction culturing immediately yielded MOB monocultures making laborious purification redundant. Both type I (Methylomonas spp.) and type II (Methylosinus sp.) MOB were isolated. The isolated methanotrophic diversity represented at least 11 different strains and several novel species based on 16S rRNA gene sequence dissimilarity. These strains possessed the particulate (100%) and soluble (64%) methane monooxygenase gene. Also, 73% of the strains could be linked to a highly active fast-growing mixed MOB community. In conclusion, miniaturized extinction culturing was more efficient in rapidly isolating numerous MOB requiring little effort and fewer materials, compared with the more widely applied plating procedure. This miniaturized approach allowed straightforward isolation and could be very useful for subsequent screening of desired characteristics, in view of their future biotechnological potential.

  2. The effects of fermentation and adsorption using lactic acid bacteria culture broth on the feed quality of rice straw

    Institute of Scientific and Technical Information of China (English)

    LIU Jing-jing; LIU Xiao-ping; REN Ji-wei; ZHAO Hong-yan; YUAN Xu-feng; WANG Xiao-fen; Abdelfattah Z M Salem; CUI Zong-jun

    2015-01-01

    To improve the nutritional value and the palatability of air-dried rice straw, culture broth of the lactic acid bacteria community SFC-2 was used to examine the effects of two different treatments, fermentation and adsorption. Air-dried and chopped rice straw was treated with either fermentation for 30 d after adding 1.5 L nutrient solution (50 mL inocula L–1, 1.2×1012 CFU mL–1 inocula) kg–1 straw dry matter, or spraying a large amount of culture broth (1.5 L kg–1 straw dry matter, 1.5×1011 CFU mL–1 culture broth) on the straw and al owing it to adsorb for 30 min. The feed quality and aerobic stability of the resulting forage were examined. Both treatments improved the feed quality of rice straw, and adsorption was better than fermen-tation for preserving nutrients and improving digestibility, as evidenced by higher dry matter (DM) and crude protein (CP) concentrations, lower neutral detergent ifber (NDF), acid detergent ifber (ADF) and NH3-N concentrations, as wel as higher lactic acid production and in vitro digestibility of DM (IVDMD). The aerobic stability of the adsorbed straw and the fermented straw was 392 and 480 h, respectively. After being exposed to air, chemical components and microbial community of the fermented straw were more stable than the adsorbed straw.

  3. Role in Cheese Flavour Formation of Heterofermentative Lactic Acid Bacteria from Mesophilic Starter Cultures

    DEFF Research Database (Denmark)

    Pedersen, Thomas Bæk

    -starters including strains from our culture collection were used throughout the project. Initially selected strains were screened for enzyme activities involved in cheese flavour formation after growth in a cheese based medium (CBM) and in a nutrient rich growth medium (MRS). The Leuconostoc strains had low...

  4. Lactic acid bacteria as protective cultures in fermented pork meat to prevent Clostridium spp. growth.

    Science.gov (United States)

    Di Gioia, Diana; Mazzola, Giuseppe; Nikodinoska, Ivana; Aloisio, Irene; Langerholc, Tomaz; Rossi, Maddalena; Raimondi, Stefano; Melero, Beatriz; Rovira, Jordi

    2016-10-17

    In meat fermented foods, Clostridium spp. growth is kept under control by the addition of nitrite. The growing request of consumers for safer products has led to consider alternative bio-based approaches, the use of protective cultures being one of them. This work is aimed at checking the possibility of using two Lactobacillus spp. strains as protective cultures against Clostridium spp. in pork ground meat for fermented salami preparation. Both Lactobacillus strains displayed anti-clostridia activity in vitro using the spot agar test and after co-culturing them in liquid medium with each Clostridium strain. Only one of them, however, namely L. plantarum PCS20, was capable of effectively surviving in ground meat and of performing anti-microbial activity in carnis in a challenge test where meat was inoculated with the Clostridium strain. Therefore, this work pointed out that protective cultures can be a feasible approach for nitrite reduction in fermented meat products. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Detection of Bacteria by Fluorescence in Situ Hybridization in Culture-Negative Soft Tissue Filler Lesions

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Tolker-Nielsen, Tim; Givskov, Michael

    2009-01-01

    BACKGROUND Adverse reactions to polyacrylamide gel occur as swellings or nodules, and controversy exists whether these are due to bacterial infection or an autoimmune reaction to the filler. OBJECTIVES Biopsies from culture-negative long-lasting nodules after injection with different types of pol...

  6. Evaluation of ultraviolet germicidal irradiation in reducing the airborne cultural bacteria concentrations in an elementary school in the Midwestern United States.

    Science.gov (United States)

    Su, Chunxiao; Lau, Josephine; Gibbs, Shawn G

    2015-05-01

    This article describes a casestudythe authors conducted in an elementary school in the Midwest. The objective was to evaluate the performance of ultraviolet germicidal irradiation (UGVI) to reduce the bioaerosol concentration in a classroom. Two fourth grade classrooms with the same dimensions were studied. One classroom was designated as the UVGI group and the other as the control group. Two-stage Tisch culturable impactors were utilized for collecting airborne bacteria with monthly samples collected from October 2012 to January 2013. Nonparametric methods were applied and p-values smaller than .05 were deemed significant. The concentrations of airborne cultural bacteria with a smaller size (1-8 pm) and the total bacterial concentrations from the UVGI classroom were significantly lower than those of the control room in three of four sampling months. These results could provide the preliminary results necessary to determine the effectiveness of upper-room UVGI in reducing the concentration of airborne cultural bacteria in classrooms and other buildings.

  7. Increasing the Richness of Culturable Arsenic-Tolerant Bacteria from Theonella swinhoei by Addition of Sponge Skeleton to the Growth Medium.

    Science.gov (United States)

    Keren, Ray; Lavy, Adi; Ilan, Micha

    2016-05-01

    Theonella swinhoei is an arsenic hyper-accumulator sponge, harboring a multitude of associated bacteria. These bacteria reside in the mesohyl, the dense extracellular matrix of the sponge. Previous elemental analysis of separated cell fractions from the sponge had determined that arsenic is localized to the associated bacteria. Subsequently, sponge-associated arsenic-tolerant bacteria were isolated here and grouped into 15 operational taxonomic units (OTUs, 97% similarity). Both culture-dependent and culture-independent work had revealed that T. swinhoei harbors a highly diverse bacterial community. It was thus hypothesized the acclimation of bacteria in the presence of a sponge skeleton, better mimicking its natural environment, would increase the yield of isolation of sponge-associated bacteria. Using seven modularly designed media, 380 bacteria isolates were grown and grouped into 22 OTUs. Inclusion of sponge skeleton in the growth medium promoted bacterial growth in all seven media, accounting for 20 of the 22 identified OTUs (the other two in a medium without skeleton). Diversity and richness indices were calculated for each treatment or combination of treatments with shared growth parameters. Integrating data inherent in the modularly designed media with the ecological indices led to the formation of new hypotheses regarding the aeration conditions and expected arsenic form in situ. Both aerobic and anoxic conditions are expected to occur in the sponge (temporally and/or spatially). Arsenate is expected to be the dominant (or even the only) arsenic form in the sponge.

  8. Modelling TCE degradation by a mixed culture of methane-oxidizing bacteria

    DEFF Research Database (Denmark)

    Broholm, Kim; Christensen, Thomas Højlund; Jensen, Bjørn K.

    1992-01-01

    A model describing the growth of bacteria and the degradation of methane and trichloroethylene (TCE) based on the concept of competitive inhibition is proposed. The model has been applied to laboratory batch experiments representing different initial TCE concentrations (50–4300 μg/l) and initial...... methane concentrations (0.53–3.2 mg/l). The proposed model simulated successfully the data obtained for initial methane concentration (less than 1.8 mg/l), causing constant experimental growth conditions during the experiments. This indicates that the interactions between methane and TCE degradation can...... be explained as competitive inhibition. The model simulations of the results from the experiments with the highest initial methane concentration of 3.2 mg/l failed, supposedly because the growth conditions changed during the experiments. The proposed model is a useful engineering tool for design of treatment...

  9. Phylogenetic diversity of culturable bacteria in surface seawater from the Drake Passage, Antarctica

    Science.gov (United States)

    Li, Zhao; Xing, Mengxin; Wang, Wei; Wang, Dan; Zhu, Jiancheng; Sun, Mi

    2016-09-01

    The Drake Passage is located between the Antarctic Peninsula and Tierra del Fuego in the south of South America. Surface seawater samples were collected at seven sites in the Drake Passage during the austral summer of 2012. The 16S rRNA sequences were analyzed from 187 isolated bacterial strains. Three phyla, 29 genera and 56 species were identified. The three phyla were Actinobacteria, Firmicutes and Proteobacteria; the Proteobacteria included α-Proteobacteria, β-Proteobacteria and γ-Proteobacteria. γ-Proteobacteria, Actinobacteria and Firmicutes were the dominant class or phyla in terms of quantity and species. Gram-positive bacteria (Actinobacteria and Firmicutes) accounted for 57.8% of all types identified. There were nine dominant genera, including Curtobacterium, Staphylococcus, and Halomonas, and 14 dominant species including Curtobacterium flaccumfaciens, Curtobacterium pusillum, and Staphylococcus sciuri. Of the strains identified, 87.2% were catalase positive or weakly positive.

  10. Thermal adaptation of heterotrophic soil respiration in laboratory microcosms.

    Science.gov (United States)

    Mark A. Bradford; Brian W. Watts; Christian A. Davies

    2010-01-01

    Respiration of heterotrophic microorganisms decomposing soil organic carbon releases carbon dioxide from soils to the atmosphere. In the short term, soil microbial respiration is strongly dependent on temperature. In the long term, the response of heterotrophic soil respiration to temperature is uncertain. However, following established evolutionary tradeoffs, mass-...

  11. The prediction of bacteria type and culture growth phase by an electronic nose with a multi-layer perceptron network

    Science.gov (United States)

    Gardner, J. W.; Craven, M.; Dow, C.; Hines, E. L.

    1998-01-01

    An investigation into the use of an electronic nose to predict the class and growth phase of two potentially pathogenic micro-organisms, Eschericha coli ( E. coli) and Staphylococcus aureus ( S. aureus), has been performed. In order to do this we have developed an automated system to sample, with a high degree of reproducibility, the head space of bacterial cultures grown in a standard nutrient medium. Head spaces have been examined by using an array of six different metal oxide semiconducting gas sensors and classified by a multi-layer perceptron (MLP) with a back-propagation (BP) learning algorithm. The performance of 36 different pre-processing algorithms has been studied on the basis of nine different sensor parameters and four different normalization techniques. The best MLP was found to classify successfully 100% of the unknown S. aureus samples and 92% of the unknown E. coli samples, on the basis of a set of 360 training vectors and 360 test vectors taken from the lag, log and stationary growth phases. The real growth phase of the bacteria was determined from optical cell counts and was predicted from the head space samples with an accuracy of 81%. We conclude that these results show considerable promise in that the correct prediction of the type and growth phase of pathogenic bacteria may help both in the more rapid treatment of bacterial infections and in the more efficient testing of new anti-biotic drugs.

  12. Adhesion of Pathogenic Bacteria to Food Contact Surfaces: Influence of pH of Culture

    Directory of Open Access Journals (Sweden)

    Akier Assanta Mafu

    2011-01-01

    Full Text Available The adhesion of Aeromonas hydrophila, Escherichia coli O157:H7, Salmonella Enteritidis, and Staphylococcus aureus to hydrophobic and hydrophilic surfaces in cultures with different pHs (6, 7, and 8 was studied. The results indicated that the type of material had no effect on the attachment capacity of microorganisms, while environmental pH influenced the adhesion of A. hydrophila, E. coli, and S. aureus to both solid substrates. The attachment of S. Enteritidis (P>.05 was not affected by the type of substrate or the culture pH, whereas E. coli displayed the weakest affinity for both polystyrene and glass surfaces. No correlation was established between the physicochemical properties of the materials, or the bacterial and the rate of bacterial adhesion, except for S. aureus. Photomicrographs have shown that surfaces were contaminated by small clusters of S. Enteritidis while S. aureus invaded the food contact surfaces in the form of small chains or cell aggregates.

  13. The Effect of Aluminium on Antibacterial Properties and the Content of Some Fatty Acids in Microalgae, Chlorella vulgaris Beijernick, under Heterotrophic and Autotrophic Conditions

    Directory of Open Access Journals (Sweden)

    Hossein Abbaspour

    2017-01-01

    Full Text Available Microalgae are a group of organisms, which have a significant potential for industrial applications. These algae contain large amounts of lipids compounds that are beneficial to health, have antibacterial properties, and their extracted oil can be used for biofuel. In this study, microalgae Chlorella vulgaris Beijernick was grown in the culture medium BG-11 containing aluminium (AlCl3 under autotrophic and heterotrophic conditions. In each case, survival and growth, dry weight, internal aluminium content of the sample, antibacterial properties, the content of fatty acids accumulated in the algae and secreted into the culture medium in the logarithmic growth phase were studied. Aluminium significantly increased (P < .05 growth and dry weight in autotrophic treatment compared to the heterotrophic one. Most antibacterial properties were observed in methanol extracts of heterotrophic treatments containing 0.05% glucose. Aluminium also decreased fatty acids accumulation in the algae and increased fatty acids excretion into the culture medium in heterotrophic treatment compared to the autotrophic treatment. Survival of the sample was maintained in heterotrophic conditions and showed growth without lag phase, which is indicative of rapid acclimation of organisms in heterotrophic conditions. It seems that the mentioned characteristics make the single-celled green algae Chlorella vulgaris more efficient in different ways.

  14. Continous application of bioorganic fertilizer induced resilient culturable bacteria community associated with banana Fusarium wilt suppression

    OpenAIRE

    Lin Fu; Yunze Ruan; Chengyuan Tao; Rong Li; Qirong Shen

    2016-01-01

    Fusarium wilt of banana always drives farmers to find new land for banana cultivation due to the comeback of the disease after a few cropping years. A novel idea for solving this problem is the continuous application of bioorganic fertilizer (BIO), which should be practiced from the beginning of banana planting. In this study, BIO was applied in newly reclaimed fields to pre-control banana Fusarium wilt and the culturable rhizobacteria community were evaluated using Biolog Ecoplates and cultu...

  15. Endophytic Bacteria Isolated from Panax ginseng Improves Ginsenoside Accumulation in Adventitious Ginseng Root Culture

    Directory of Open Access Journals (Sweden)

    Xiaolin Song

    2017-05-01

    Full Text Available Ginsenoside is the most important secondary metabolite of ginseng. Natural sources of wild ginseng have been overexploited. Although root culture could reduce the length of the growth cycle of ginseng, the number of ginsenosides is fewer and their contents are lower in adventitious roots of ginseng than that in ginseng cultivated in the field. In this study, we investigated the effects of endophytic bacterial elicitors on biomass and ginsenoside production in adventitious roots cultures of Panax ginseng. Endophyte LB 5-3 as an elicitor could increase biomass and ginsenoside accumulation in ginseng adventitious root culture. After 6 days elicitation with a 10.0 mL of strain LB 5-3, the content of total ginsenoside was 2.026 mg g−1 which was four times more than that in unchallenged roots. The combination of methyl jasmonate and strain LB 5-3 had a negative effect on ginseng adventitious root growth and ginsenoside production. The genomic DNA of strain LB 5-3 was sequenced, and was found to be most closely related to Bacillus altitudinis (KX230132.1. The challenged ginseng adventitious root extracts exerted inhibitory effect against the HepG2 cells, which IC50 value was 0.94 mg mL−1.

  16. Effects of artemisinin and Artemisia annua extracts on xenic bacteria isolated from clonal cultures of Histomonas meleagridis

    DEFF Research Database (Denmark)

    Thøfner, Ida; Hess, Claudia; Liebhart, Dieter

    Infection with the protozoa Histomonas meleagridis in poultry has re-emerged since the ban of effective drugs. Consequently efforts are set to find alternatives to chemotherapeutics to combat histomonosis. At present histomonads need accompanying bacteria when cultured in vitro, probably serving...... nutrient supply due to their appearance in parasitic food vacuoles. However, the relationship of the parasite and the bacteria is not fully clear. Six previously established clonal cultures of H. meleagridis were used to evaluate the effect of five Artemisia annua derived materials (i.e. dry leaves...

  17. Proteolytic and ACE-inhibitory activities of probiotic yogurt containing non-viable bacteria as affected by different levels of fat, inulin and starter culture

    OpenAIRE

    Shakerian, Mansour; Razavi,Seyed Hadi; Ziai, Seyed Ali; Khodaiyan, Faramarz; Yarmand, Mohammad Saeid; Moayedi, Ali

    2013-01-01

    In this study, the effects of fat (0.5 %, 3.2 % and 5.0 %), inulin (0.0 and 1.0 %) and starter culture (0.0 %, 0.5 %, 1.0 % and 1.5 %) on the angiotensin converting enzyme (ACE)-inhibitory activity of probiotic yogurt containing non-viable bacteria were assessed. Proteolytic activities of bacteria were also investigated. Yogurts were prepared either using a sole yogurt commercial culture including Streptococcus thermophilus and Lactobacillus delbrueckii subs. bulgaricus or bifidobacterium ani..