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Sample records for aerobic anoxygenic phototroph

  1. Aerobic Anoxygenic Phototrophic Bacteria

    PubMed Central

    Yurkov, Vladimir V.; Beatty, J. Thomas

    1998-01-01

    The aerobic anoxygenic phototrophic bacteria are a relatively recently discovered bacterial group. Although taxonomically and phylogenetically heterogeneous, these bacteria share the following distinguishing features: the presence of bacteriochlorophyll a incorporated into reaction center and light-harvesting complexes, low levels of the photosynthetic unit in cells, an abundance of carotenoids, a strong inhibition by light of bacteriochlorophyll synthesis, and the inability to grow photosynthetically under anaerobic conditions. Aerobic anoxygenic phototrophic bacteria are classified in two marine (Erythrobacter and Roseobacter) and six freshwater (Acidiphilium, Erythromicrobium, Erythromonas, Porphyrobacter, Roseococcus, and Sandaracinobacter) genera, which phylogenetically belong to the α-1, α-3, and α-4 subclasses of the class Proteobacteria. Despite this phylogenetic information, the evolution and ancestry of their photosynthetic properties are unclear. We discuss several current proposals for the evolutionary origin of aerobic phototrophic bacteria. The closest phylogenetic relatives of aerobic phototrophic bacteria include facultatively anaerobic purple nonsulfur phototrophic bacteria. Since these two bacterial groups share many properties, yet have significant differences, we compare and contrast their physiology, with an emphasis on morphology and photosynthetic and other metabolic processes. PMID:9729607

  2. Ecology of aerobic anoxygenic phototrophs in aquatic environments.

    PubMed

    Koblížek, Michal

    2015-11-01

    Recognition of the environmental role of photoheterotrophic bacteria has been one of the main themes of aquatic microbiology over the last 15 years. Aside from cyanobacteria and proteorhodopsin-containing bacteria, aerobic anoxygenic phototrophic (AAP) bacteria are the third most numerous group of phototrophic prokaryotes in the ocean. This functional group represents a diverse assembly of species which taxonomically belong to various subgroups of Alpha-, Beta- and Gammaproteobacteria. AAP bacteria are facultative photoheterotrophs which use bacteriochlorophyll-containing reaction centers to harvest light energy. The light-derived energy increases their bacterial growth efficiency, which provides a competitive advantage over heterotrophic species. Thanks to their enzymatic machinery AAP bacteria are active, rapidly growing organisms which contribute significantly to the recycling of organic matter. This chapter summarizes the current knowledge of the ecology of AAP bacteria in aquatic environments, implying their specific role in the microbial loop. PMID:26139241

  3. Diverse Arrangement of Photosynthetic Gene Clusters in Aerobic Anoxygenic Phototrophic Bacteria

    PubMed Central

    Zheng, Qiang; Zhang, Rui; Koblížek, Michal; Boldareva, Ekaterina N.; Yurkov, Vladimir; Yan, Shi; Jiao, Nianzhi

    2011-01-01

    Background Aerobic anoxygenic photototrophic (AAP) bacteria represent an important group of marine microorganisms inhabiting the euphotic zone of the ocean. They harvest light using bacteriochlorophyll (BChl) a and are thought to be important players in carbon cycling in the ocean. Methodology/Principal Findings Aerobic anoxygenic phototrophic (AAP) bacteria represent an important part of marine microbial communities. Their photosynthetic apparatus is encoded by a number of genes organized in a so-called photosynthetic gene cluster (PGC). In this study, the organization of PGCs was analyzed in ten AAP species belonging to the orders Rhodobacterales, Sphingomonadales and the NOR5/OM60 clade. Sphingomonadales contained comparatively smaller PGCs with an approximately size of 39 kb whereas the average size of PGCs in Rhodobacterales and NOR5/OM60 clade was about 45 kb. The distribution of four arrangements, based on the permutation and combination of the two conserved regions bchFNBHLM-LhaA-puhABC and crtF-bchCXYZ, does not correspond to the phylogenetic affiliation of individual AAP bacterial species. While PGCs of all analyzed species contained the same set of genes for bacteriochlorophyll synthesis and assembly of photosynthetic centers, they differed largely in the carotenoid biosynthetic genes. Spheroidenone, spirilloxanthin, and zeaxanthin biosynthetic pathways were found in each clade respectively. All of the carotenoid biosynthetic genes were found in the PGCs of Rhodobacterales, however Sphingomonadales and NOR5/OM60 strains contained some of the carotenoid biosynthetic pathway genes outside of the PGC. Conclusions/Significance Our investigations shed light on the evolution and functional implications in PGCs of marine aerobic anoxygenic phototrophs, and support the notion that AAP are a heterogenous physiological group phylogenetically scattered among Proteobacteria. PMID:21949847

  4. Phylogenetically Diverse Aerobic Anoxygenic Phototrophic Bacteria Isolated from Epilithic Biofilms in Tama River, Japan

    PubMed Central

    Hirose, Setsuko; Matsuura, Katsumi; Haruta, Shin

    2016-01-01

    The diversity of aerobic anoxygenic phototrophic (AAP) bacteria in freshwater environments, particularly in rivers, has not been examined in as much detail as in ocean environments. In the present study, we investigated the phylogenetic and physiological diversities of AAP bacteria in biofilms that developed on submerged stones in a freshwater river using culture methods. The biofilms collected were homogenized and inoculated on solid media and incubated aerobically in the dark. Sixty-eight red-, pink-, yellow-, orange-, or brown-colored colonies were isolated, and, of these, 28 isolates contained the photosynthetic pigment, bacteriochlorophyll (BChl) a. Phylogenetic analyses based on 16S rRNA gene sequences showed that the isolates were classified into 14 groups in 8 operational taxonomic units (OTUs) and distributed in the orders Rhodospirillales, Rhodobacterales, and Sphingomonadales of Alphaproteobacteria and in Betaproteobacteria. Physiological analyses confirmed that none of the representative isolates from any of the groups grew under anaerobic phototrophic conditions. Seven isolates in 4 OTUs showed a 16S rRNA gene sequence identity of 98.0% or less with any established species, suggesting the presence of previously undescribed species of AAP bacteria. Six isolates in 2 other OTUs had the closest relatives, which have not been reported to be AAP bacteria. Physiological comparisons among the isolates revealed differences in preferences for nutrient concentrations, BChl contents, and light-harvesting proteins. These results suggest that diverse and previously unknown AAP bacteria inhabit river biofilms. PMID:27453124

  5. The variability of light-harvesting complexes in aerobic anoxygenic phototrophs.

    PubMed

    Selyanin, Vadim; Hauruseu, Dzmitry; Koblížek, Michal

    2016-04-01

    Light-harvesting capacity was investigated in six species of aerobic anoxygenic phototrophic (AAP) bacteria using absorption spectroscopy, fluorescence emission spectroscopy, and pigment analyses. Aerobically grown AAP cells contained approx. 140-1800 photosynthetic reaction centers per cell, an order of magnitude less than purple non-sulfur bacteria grown semiaerobically. Three of the studied AAP species did not contain outer light-harvesting complexes, and the size of their reaction center core complexes (RC-LH1 core complexes) varied between 29 and 36 bacteriochlorophyll molecules. In AAP species containing accessory antennae, the size was frequently reduced, providing between 5 and 60 additional bacteriochlorophyll molecules. In Roseobacter litoralis, it was found that cells grown at a higher light intensity contained more reaction centers per cell, while the size of the light-harvesting complexes was reduced. The presented results document that AAP species have both the reduced number and size of light-harvesting complexes which is consistent with the auxiliary role of phototrophy in this bacterial group. PMID:26482589

  6. Pyrosequencing analysis of aerobic anoxygenic phototrophic bacterial community structure in the oligotrophic western Pacific Ocean.

    PubMed

    Zheng, Qiang; Liu, Yanting; Steindler, Laura; Jiao, Nianzhi

    2015-04-01

    Aerobic anoxygenic phototrophic bacteria (AAPB) represent a widespread functional bacterial group defined by their obligate aerobic and facultative photoheterotrophic abilities. They are an active part of the marine microbial community as revealed by a large number of previous investigations. Here, we made an in-depth comparison of AAPB community structures in the subsurface water and the upper twilight zone of the western Pacific Ocean using high-throughput sequencing based on the pufM gene. Approximately, 100 000 sequences, grouped into 159 OTUs (94% cut-off value), included 44 and 24 OTUs unique to the subsurface and the upper twilight zone, respectively; 92 OTUs were common to both subsurface and twilight zone, and 3 OTUs were found in all samples. Consistent with previous studies, AAPB belonging to the Gammaproteobacteria were the dominant group in the whole water column, followed by the alphaproteobacterial AAPB. Comparing the relative abundance distribution patterns of different clades, an obvious community-structure separation according to deeper or shallower environment could be observed. Sulfitobacter-like, Loktanella-like, Erythrobacter-like, Dinoroseobacter-like and Gamma-HIMB55-like AAPB preferred the high-light subsurface water, while Methylobacterium-like, 'Citromicrobium'-like, Roseovarius-like and Bradyrhizobium-like AAPB, the dim light environment. PMID:25724533

  7. Leucine incorporation by aerobic anoxygenic phototrophic bacteria in the Delaware estuary

    PubMed Central

    Stegman, Monica R; Cottrell, Matthew T; Kirchman, David L

    2014-01-01

    Aerobic anoxygenic phototrophic (AAP) bacteria are well known to be abundant in estuaries, coastal regions and in the open ocean, but little is known about their activity in any aquatic ecosystem. To explore the activity of AAP bacteria in the Delaware estuary and coastal waters, single-cell 3H-leucine incorporation by these bacteria was examined with a new approach that combines infrared epifluorescence microscopy and microautoradiography. The approach was used on samples from the Delaware coast from August through December and on transects through the Delaware estuary in August and November 2011. The percent of active AAP bacteria was up to twofold higher than the percentage of active cells in the rest of the bacterial community in the estuary. Likewise, the silver grain area around active AAP bacteria in microautoradiography preparations was larger than the area around cells in the rest of the bacterial community, indicating higher rates of leucine consumption by AAP bacteria. The cell size of AAP bacteria was 50% bigger than the size of other bacteria, about the same difference on average as measured for activity. The abundance of AAP bacteria was negatively correlated and their activity positively correlated with light availability in the water column, although light did not affect 3H-leucine incorporation in light–dark experiments. Our results suggest that AAP bacteria are bigger and more active than other bacteria, and likely contribute more to organic carbon fluxes than indicated by their abundance. PMID:24824666

  8. Aerobic Anoxygenic Phototrophic Bacteria in the Mid-Atlantic Bight and the North Pacific Gyre

    PubMed Central

    Cottrell, Matthew T.; Mannino, Antonio; Kirchman, David L.

    2006-01-01

    The abundance of aerobic anoxygenic phototrophic (AAP) bacteria, cyanobacteria, and heterotrophs was examined in the Mid-Atlantic Bight and the central North Pacific Gyre using infrared fluorescence microscopy coupled with image analysis and flow cytometry. AAP bacteria comprised 5% to 16% of total prokaryotes in the Atlantic Ocean but only 5% or less in the Pacific Ocean. In the Atlantic, AAP bacterial abundance was as much as 2-fold higher than that of Prochlorococcus spp. and 10-fold higher than that of Synechococcus spp. In contrast, Prochlorococcus spp. outnumbered AAP bacteria 5- to 50-fold in the Pacific. In both oceans, subsurface abundance maxima occurred within the photic zone, and AAP bacteria were least abundant below the 1% light depth. The abundance of AAP bacteria rivaled some groups of strictly heterotrophic bacteria and was often higher than the abundance of known AAP bacterial genera (Erythrobacter and Roseobacter spp.). Concentrations of bacteriochlorophyll a (BChl a) were low (∼1%) compared to those of chlorophyll a in the North Atlantic. Although the BChl a content of AAP bacteria per cell was typically 20- to 250-fold lower than the divinyl-chlorophyll a content of Prochlorococcus, the pigment content of AAP bacteria approached that of Prochlorococcus in shelf break water. Our results suggest that AAP bacteria can be quite abundant in some oceanic regimes and that their distribution in the water column is consistent with phototrophy. PMID:16391092

  9. Aerobic Anoxygenic Phototrophic Bacteria in the Mid-Atlantic Bight and the North Pacific Gyre. Revised

    NASA Technical Reports Server (NTRS)

    Cottrell, Matthew T.; Mannino, Antonio; Kirchman, David L.

    2005-01-01

    The abundance of aerobic anoxygenic phototrophic (AM) bacteria, cyanobacteria and heterotrophs was examined in the Mid-Atlantic Bight and the central North Pacific gyre using infrared fluorescence microscopy coupled with image analysis and flow cytometry. AAP bacteria comprised 5% to 16% of total prokaryotes in the Atlantic but only 5% or less in the Pacific. In the Atlantic, AAP bacterial abundance was as much as 2-fold higher than Prochlorococcus and 10-folder higher than Synechococcus. In contrast, Prochlorococcus outnumbered AAP bacteria 5- to 50-fold in the Pacific. In both oceans, subsurface abundance maxima occurred within the photic zone, and AAP bacteria were least abundant below the 1% light depth. Concentrations of bacteriochlorophyll a (BChl a) were low (approx.1%) compared to chlorophyll a. Although the BChl a content of AAP bacteria per cell was typically 20- to 250-fold lower than the divinyl-chlorophyll a content of Prochlorococcus, in shelf break water the pigment content of AAP bacteria approached that of Prochlorococcus. The abundance of AAP bacteria rivaled some groups of strictly heterotrophic bacteria and was often higher than the abundance of known AAP genera (Erythrobacter and Roseobacter spp.). The distribution of AAP bacteria in the water column, which was similar in the Atlantic and the Pacific, was consistent with phototrophy.

  10. Single-cell activity of freshwater aerobic anoxygenic phototrophic bacteria and their contribution to biomass production.

    PubMed

    Garcia-Chaves, Maria C; Cottrell, Matthew T; Kirchman, David L; Ruiz-González, Clara; Del Giorgio, Paul A

    2016-07-01

    Aerobic anoxygenic phototrophic (AAP) bacteria are photoheterotrophs that despite their low abundances have been hypothesized to play an ecologically and biogeochemically important role in aquatic systems. Characterizing this role requires a better understanding of the in situ dynamics and activity of AAP bacteria. Here we provide the first assessment of the single-cell activity of freshwater AAP bacteria and their contribution to total bacterial production across lakes spanning a wide trophic gradient, and explore the role of light in regulating AAP activity. The proportion of cells that were active in leucine incorporation and the level of activity per cell were consistently higher for AAP than for bulk bacteria across lakes. As a result, AAP bacteria contributed disproportionately more to total bacterial production than to total bacterial abundance. Interestingly, although environmentally driven patterns in activity did not seem to differ largely between AAP and bulk bacteria, their response to light did, and exposure to light resulted in increases in the proportion of active AAP bacteria with no clear effect on their cell-specific activity. This suggests that light may play a role in the activation of AAP bacteria, enabling these photoheterotrophs to contribute more to the carbon cycle than suggested by their abundance. PMID:26771928

  11. Bacteriochlorophyll and community structure of aerobic anoxygenic phototrophic bacteria in a particle-rich estuary.

    PubMed

    Cottrell, Matthew T; Ras, Josephine; Kirchman, David L

    2010-07-01

    Photoheterotrophic microbes use organic substrates and light energy to satisfy their demand for carbon and energy and seem to be well adapted to eutrophic estuarine and oligotrophic oceanic environments. One type of photoheterotroph, aerobic anoxygenic phototrophic (AAP) bacteria, is especially abundant in particle-rich, turbid estuaries. To explore questions regarding the controls of these photoheterotrophic bacteria, we examined their abundance by epifluorescence microscopy, concentrations of the light-harvesting pigment, bacteriochlorophyll a (BChl a) and the diversity of pufM and 16S ribosomal RNA (rRNA) genes in the Chesapeake Bay. Concentrations of BChl a varied substantially, much more so than AAP bacterial abundance, along the estuarine salinity gradient. The BChl a concentration was correlated with turbidity only when oceanic and estuarine waters were considered together. Concentrations of BChl a and BChl a quotas were higher in particle-associated than in free-living AAP bacterial communities and appear to reflect physiological adaptation, not different AAP bacterial communities; pufM genes did not differ between particle-associated and free-living communities. In contrast, particle-associated and free-living bacterial communities were significantly different, on the basis of the analysis of 16S rRNA genes. The BChl a quota of AAP bacteria was not correlated with turbidity, suggesting that pigment synthesis varies in direct response to particles, not light attenuation. The AAP bacteria seem to synthesize more BChl a when dissolved and particulate substrates are available than when only dissolved materials are accessible, which has implications for understanding the impact of substrates on the level of photoheterotrophy compared with heterotrophy in AAP bacteria. PMID:20182527

  12. Diversity of cultivated and metabolically active aerobic anoxygenic phototrophic bacteria along an oligotrophic gradient in the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Jeanthon, C.; Boeuf, D.; Dahan, O.; Le Gall, F.; Garczarek, L.; Bendif, E. M.; Lehours, A.-C.

    2011-07-01

    Aerobic anoxygenic phototrophic (AAP) bacteria play significant roles in the bacterioplankton productivity and biogeochemical cycles of the surface ocean. In this study, we applied both cultivation and mRNA-based molecular methods to explore the diversity of AAP bacteria along an oligotrophic gradient in the Mediterranean Sea in early summer 2008. Colony-forming units obtained on three different agar media were screened for the production of bacteriochlorophyll-a (BChl-a), the light-harvesting pigment of AAP bacteria. BChl-a-containing colonies represented a low part of the cultivable fraction. In total, 54 AAP strains were isolated and the phylogenetic analyses based on their 16S rRNA and pufM genes showed that they were all affiliated to the Alphaproteobacteria. The most frequently isolated strains belonged to Citromicrobium bathyomarinum, and Erythrobacter and Roseovarius species. Most other isolates were related to species not reported to produce BChl-a and/or may represent novel taxa. Direct extraction of RNA from seawater samples enabled the analysis of the expression of pufM, the gene coding for the M subunit of the reaction centre complex of aerobic anoxygenic photosynthesis. Clone libraries of pufM gene transcripts revealed that most phylotypes were highly similar to sequences previously recovered from the Mediterranean Sea and a large majority (~94 %) was affiliated to the Gammaproteobacteria. The most abundantly detected phylotypes occurred in the western and eastern Mediterranean basins. However, some were exclusively detected in the eastern basin, reflecting the highest diversity of pufM transcripts observed in this ultra-oligotrophic region. To our knowledge, this is the first study to document extensively the diversity of AAP isolates and to unveil the active AAP community in an oligotrophic marine environment. By pointing out the discrepancies between culture-based and molecular methods, this study highlights the existing gaps in the understanding

  13. Diversity of cultivated and metabolically active aerobic anoxygenic phototrophic bacteria along an oligotrophic gradient in the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Jeanthon, C.; Boeuf, D.; Dahan, O.; Le Gall, F.; Garczarek, L.; Bendif, E. M.; Lehours, A.-C.

    2011-05-01

    Aerobic anoxygenic phototrophic (AAP) bacteria play significant roles in the bacterioplankton productivity and biogeochemical cycles of the surface ocean. In this study, we applied both cultivation and mRNA-based molecular methods to explore the diversity of AAP bacteria along an oligotrophic gradient in the Mediterranean Sea in early summer 2008. Colony-forming units obtained on three different agar media were screened for the production of bacteriochlorophyll-a (BChl-a), the light-harvesting pigment of AAP bacteria. BChl-a-containing colonies represented a low part of the cultivable fraction. In total, 52 AAP strains were isolated and the phylogenetic analyses based on their 16S rRNA and pufM genes showed that they were all affiliated to the Alphaproteobacteria. The most frequently isolated strains belonged to Citromicrobium bathyomarinum, and Erythrobacter and Roseovarius species. Most other isolates were related to species not reported to produce BChl-a and/or may represent novel taxa. Direct extraction of RNA from seawater samples enabled the analysis of the expression of pufM, the gene coding for the M subunit of the reaction centre complex of aerobic anoxygenic photosynthesis. Clone libraries of pufM gene transcripts revealed that most phylotypes were highly similar to sequences previously recovered from the Mediterranean Sea and a large majority (~94%) was affiliated with the Gammaproteobacteria. The most abundantly detected phylotypes occurred in the western and eastern Mediterranean basins. However, some were exclusively detected in the eastern basin, reflecting the highest diversity of pufM transcripts observed in this ultra-oligotrophic region. To our knowledge, this is the first study to document extensively the diversity of AAP isolates and to unveil the active AAP community in an oligotrophic marine environment. By pointing out the discrepancies between culture-based and molecular methods, this study highlights the existing gaps in the understanding

  14. Carotenoid charge transfer states and their role in energy transfer processes in LH1-RC complexes from aerobic anoxygenic phototrophs.

    PubMed

    Šlouf, Václav; Fuciman, Marcel; Dulebo, Alexander; Kaftan, David; Koblížek, Michal; Frank, Harry A; Polívka, Tomáš

    2013-09-26

    Light-harvesting complexes ensure necessary flow of excitation energy into photosynthetic reaction centers. In the present work, transient absorption measurements were performed on LH1-RC complexes isolated from two aerobic anoxygenic phototrophs (AAPs), Roseobacter sp. COL2P containing the carotenoid spheroidenone, and Erythrobacter sp. NAP1 which contains the carotenoids zeaxanthin and bacteriorubixanthinal. We show that the spectroscopic data from the LH1-RC complex of Roseobacter sp. COL2P are very similar to those previously reported for Rhodobacter sphaeroides, including the transient absorption spectrum originating from the intramolecular charge-transfer (ICT) state of spheroidenone. Although the ICT state is also populated in LH1-RC complexes of Erythrobacter sp. NAP1, its appearance is probably related to the polarity of the bacteriorubixanthinal environment rather than to the specific configuration of the carotenoid, which we hypothesize is responsible for populating the ICT state of spheroidenone in LH1-RC of Roseobacter sp. COL2P. The population of the ICT state enables efficient S1/ICT-to-bacteriochlorophyll (BChl) energy transfer which would otherwise be largely inhibited for spheroidenone and bacteriorubixanthinal due to their low energy S1 states. In addition, the triplet states of these carotenoids appear well-tuned for efficient quenching of singlet oxygen or BChl-a triplets, which is of vital importance for oxygen-dependent organisms such as AAPs. PMID:23130956

  15. Influence of selected environmental factors on the abundance of aerobic anoxygenic phototrophs in peat-bog lakes.

    PubMed

    Lew, Sylwia; Lew, Marcin; Koblížek, Michal

    2016-07-01

    Aerobic anoxygenic phototrophs (AAPs) are photoheterotrophic prokaryotes that are widespread in many limnic and marine environments. So far, little is known about their distribution in peat-bog lakes. Seventeen peat-bog lakes were sampled during three summer seasons 2009, 2011, and 2012, and the vertical distribution of AAPs was determined by infrared epifluorescence microscopy. The analysis demonstrated that in the surface layers of the studied lakes, AAP abundance ranged from 0.3 to 12.04 × 10(5) cells mL(-1), which represents <1 to 18.3 % of the total bacteria. The vertical distribution of AAPs confirmed their presence in the upper parts of the water column with minimum numbers in the anoxic bottom waters. We have shown that the AAP abundance was significantly positively correlated with the water pH, and the highest proportion of photoheterotrophs was found in peat-bog lakes with a pH between 6.7 and 7.6. Our results demonstrated an influence of water acidity on the abundance of AAPs, which may reflect a fundamental difference in the microbial composition between acidic and pH neutral peat-bog lakes. PMID:27032635

  16. Patterns in Abundance, Cell Size and Pigment Content of Aerobic Anoxygenic Phototrophic Bacteria along Environmental Gradients in Northern Lakes

    PubMed Central

    Fauteux, Lisa; Cottrell, Matthew T.; Kirchman, David L.; Borrego, Carles M.; Garcia-Chaves, Maria Carolina; del Giorgio, Paul A.

    2015-01-01

    There is now evidence that aerobic anoxygenic phototrophic (AAP) bacteria are widespread across aquatic systems, yet the factors that determine their abundance and activity are still not well understood, particularly in freshwaters. Here we describe the patterns in AAP abundance, cell size and pigment content across wide environmental gradients in 43 temperate and boreal lakes of Québec. AAP bacterial abundance varied from 1.51 to 5.49 x 105 cells mL-1, representing <1 to 37% of total bacterial abundance. AAP bacteria were present year-round, including the ice-cover period, but their abundance relative to total bacterial abundance was significantly lower in winter than in summer (2.6% and 7.7%, respectively). AAP bacterial cells were on average two-fold larger than the average bacterial cell size, thus AAP cells made a greater relative contribution to biomass than to abundance. Bacteriochlorophyll a (BChla) concentration varied widely across lakes, and was not related to AAP bacterial abundance, suggesting a large intrinsic variability in the cellular pigment content. Absolute and relative AAP bacterial abundance increased with dissolved organic carbon (DOC), whereas cell-specific BChla content was negatively related to chlorophyll a (Chla). As a result, both the contribution of AAP bacteria to total prokaryotic abundance, and the cell-specific BChla pigment content were positively correlated with the DOC:Chla ratio, both peaking in highly colored, low-chlorophyll lakes. Our results suggest that photoheterotrophy might represent a significant ecological advantage in highly colored, low-chlorophyll lakes, where DOC pool is chemically and structurally more complex. PMID:25927833

  17. Formation of Polyhydroxyalkanoate in Aerobic Anoxygenic Phototrophic Bacteria and Its Relationship to Carbon Source and Light Availability▿

    PubMed Central

    Xiao, Na; Jiao, Nianzhi

    2011-01-01

    Aerobic anoxygenic phototrophic bacteria (AAPB) are unique players in carbon cycling in the ocean. Cellular carbon storage is an important mechanism regulating the nutrition status of AAPB but is not yet well understood. In this paper, six AAPB species (Dinoroseobacter sp. JL1447, Roseobacter denitrificans OCh 114, Roseobacter litoralis OCh 149, Dinoroseobacter shibae DFL 12T, Labrenzia alexandrii DFL 11T, and Erythrobacter longus DSMZ 6997) were examined, and all of them demonstrated the ability to form the carbon polymer polyhydroxyalkanoate (PHA) in the cell. The PHA in Dinoroseobacter sp. JL1447 was identified as poly-beta-hydroxybutyrate (PHB) according to evidence from Fourier transform infrared spectroscopy, differential scanning calorimetry, and 1H nuclear magnetic resonance spectroscopy examinations. Carbon sources turned out to be critical for PHA production in AAPB. Among the eight media tested with Dinoroseobacter sp. JL1447, sodium acetate, giving a PHA production rate of 72%, was the most productive carbon source, followed by glucose, with a 68% PHA production rate. Such PHA production rates are among the highest recorded for all bacteria. The C/N ratio of substrates was verified by the experiments as another key factor in PHA production. In the case of R. denitrificans OCh 114, PHA was not detected when the organism was cultured at C/N ratios of <2 but became apparent at C/N ratios of >3. Light is also important for the formation of PHA in AAPB. In the case of Dinoroseobacter sp. JL1447, up to a one-quarter increase in PHB production was observed when the culture underwent growth in a light-dark cycle compared to growth completely in the dark. PMID:21908634

  18. A marine inducible prophage vB_CibM-P1 isolated from the aerobic anoxygenic phototrophic bacterium Citromicrobium bathyomarinum JL354

    NASA Astrophysics Data System (ADS)

    Zheng, Qiang; Zhang, Rui; Xu, Yongle; , Richard Allen White, III; Wang, Yu; Luo, Tingwei; Jiao, Nianzhi

    2014-11-01

    A prophage vB_CibM-P1 was induced by mitomycin C from the epipelagic strain Citromicrobium bathyomarinum JL354, a member of the alpha-IV subcluster of marine aerobic anoxygenic phototrophic bacteria (AAPB). The induced bacteriophage vB_CibM-P1 had Myoviridae-like morphology and polyhedral heads (approximately capsid 60-100 nm) with tail fibers. The vB_CibM-P1 genome is ~38 kb in size, with 66.0% GC content. The genome contains 58 proposed open reading frames that are involved in integration, DNA packaging, morphogenesis and bacterial lysis. VB_CibM-P1 is a temperate phage that can be directly induced in hosts. In response to mitomycin C induction, virus-like particles can increase to 7 × 109 per ml, while host cells decrease an order of magnitude. The vB_CibM-P1 bacteriophage is the first inducible prophage from AAPB.

  19. Isolation of Optically Targeted Single Bacteria by Application of Fluidic Force Microscopy to Aerobic Anoxygenic Phototrophs from the Phyllosphere

    PubMed Central

    Stiefel, Philipp; Zambelli, Tomaso

    2013-01-01

    In their natural environment, bacteria often behave differently than they do under laboratory conditions. To gain insight into the physiology of bacteria in situ, dedicated approaches are required to monitor their adaptations and specific behaviors under environmental conditions. Optical microscopy is crucial for the observation of fundamental characteristics of bacteria, such as cell shape, size, and marker gene expression. Here, fluidic force microscopy (FluidFM) was exploited to isolate optically selected bacteria for subsequent identification and characterization. In this study, bacteriochlorophyll-producing bacteria, which can be visualized due to their characteristic fluorescence in the infrared range, were isolated from leaf washes. Bacterial communities from the phyllosphere were investigated because they harbor genes indicative of aerobic anoxygenic photosynthesis. Our data show that different species of Methylobacterium express their photosystem in planta, and they show a distinct pattern of bacteriochlorophyll production under laboratory conditions that is dependent on supplied carbon sources. PMID:23770907

  20. Remotely Detectable Biosignatures of Anoxygenic Phototrophs

    NASA Astrophysics Data System (ADS)

    Parenteau, M. N.; Kiang, N. Y.; Blankenship, R. E.; Sanromá, E.; Palle Bago, E.; Hoehler, T. M.; Pierson, B. K.

    2014-12-01

    Many astrobiological/exobiological studies have been directed at searching for evidence of life on planetary bodies within our solar system, but the search for life does not have to be restricted to our stellar neighborhood. The field of exoplanet research has grown rapidly over the last several years. Studies have moved beyond detection to assessing the habitability and biosignatures of these worlds. The biosignatures considered thus far focus on biogenic gases and planetary surface features, such as the light reflected from the surface of plants to generate the "red edge" of vegetation. Much work has focused on detecting biosignatures of higher life forms (vegetation) on exoplanets. However, land plants only appeared on the Earth 450 million years ago, and required a long path of photosynthetic evolution. There is a dearth of studies examining how light might interact with much simpler, more evolutionarily ancient pigmented communities, such as photosynthetic microbes. These anoxygenic phototrophs, which have inhabited Earth for nearly 80% of its history, may dominate exoplanets at a similar stage of evolution as the Archean or Paleoproterozoic Earth. Similar to the remotely detectable "red edge" of chlorophyll a - containing vegetation, we measured the reflectance spectra of pure cultures and environmental samples of purple sulfur, purple non-sulfur, heliobacteria, green sulfur, and green non-sulfur anoxygenic phototrophs. We observed an increase in reflectivity just past the absorption maximum for the bacteriochlorophyll pigments. Since this reflectance feature is shifted into the NIR compared to that of the red edge of vegetation, we're calling this the "NIR edge" of anoxygenic phototrophs. The bacteriochlorophyll pigments are particularly well suited to absorb the far-red and near-infrared radiation emitted by M dwarf stars, the most common type of star in our galaxy. Therefore these phototrophs serve as model organisms for photosynthesis adapted to

  1. [New Strains of an Aerobic Anoxygenic Phototrophic Bacterium Porphyrobacter donghaensis Isolated from a Siberian Thermal Spring and a Low-Mineralization Lake].

    PubMed

    Nuyanzina-Boldareva, E N; Akimova, V N; Takaiche, S; Gorlenko, V M

    2016-01-01

    A strain of aerobic anoxygenic phototrophic bacteria (AAPB) isolated from the surface of a cyano- bacterial mat of an Eastern Siberian thermal spring (40 C) and designated Se 4 was identified as Porphyro- bacter donghaensis according to its 16S rRNA gene sequence. A DNA-DNA hybridization level of 95% was determined between strain Se-4 and the type strain of this species; SW-132@T. The isolate was an obligate aerobe,. forming orange round colonies on solid media, which turn red in the course of growth. The cells were motile rods capable of branching. The cells divided by uniform fission by constriction. Optimal growth was observed at pH 7.5 and NaCl concentrations from 0 to 1 g/L. The pigments present were carotenoids and bacteriochlorophyll a. Another Porphyrobacter donghaensis strain, Noj- 1, isolated from a purple mat developing on the surface of a coastal set-up in a steppe low-mineralization (1.5 g/L) soda lake Nozhii (Eastern Siberia) possessed similar characteristics. Thus, the AAPB species Porphyrobacter donghaensis was shown to-occur, apart from its known habitat, marine environments, in low-mineralization soda lakes and freshwater thermal springs. Description of the species Porphyrobacter donghaensis was amended. PMID:27301129

  2. Picoplankton Bloom in Global South? A High Fraction of Aerobic Anoxygenic Phototrophic Bacteria in Metagenomes from a Coastal Bay (Arraial do Cabo—Brazil)

    PubMed Central

    Cuadrat, Rafael R. C.; Ferrera, Isabel; Grossart, Hans-Peter; Dávila, Alberto M. R.

    2016-01-01

    Abstract Marine habitats harbor a great diversity of microorganism from the three domains of life, only a small fraction of which can be cultivated. Metagenomic approaches are increasingly popular for addressing microbial diversity without culture, serving as sensitive and relatively unbiased methods for identifying and cataloging the diversity of nucleic acid sequences derived from organisms in environmental samples. Aerobic anoxygenic phototrophic bacteria (AAP) play important roles in carbon and energy cycling in aquatic systems. In oceans, those bacteria are widely distributed; however, their abundance and importance are still poorly understood. The aim of this study was to estimate abundance and diversity of AAPs in metagenomes from an upwelling affected coastal bay in Arraial do Cabo, Brazil, using in silico screening for the anoxygenic photosynthesis core genes. Metagenomes from the Global Ocean Sample Expedition (GOS) were screened for comparative purposes. AAPs were highly abundant in the free-living bacterial fraction from Arraial do Cabo: 23.88% of total bacterial cells, compared with 15% in the GOS dataset. Of the ten most AAP abundant samples from GOS, eight were collected close to the Equator where solar irradiation is high year-round. We were able to assign most retrieved sequences to phylo-groups, with a particularly high abundance of Roseobacter in Arraial do Cabo samples. The high abundance of AAP in this tropical bay may be related to the upwelling phenomenon and subsequent picoplankton bloom. These results suggest a link between upwelling and light abundance and demonstrate AAP even in oligotrophic tropical and subtropical environments. Longitudinal studies in the Arraial do Cabo region are warranted to understand the dynamics of AAP at different locations and seasons, and the ecological role of these unique bacteria for biogeochemical and energy cycling in the ocean. PMID:26871866

  3. Picoplankton Bloom in Global South? A High Fraction of Aerobic Anoxygenic Phototrophic Bacteria in Metagenomes from a Coastal Bay (Arraial do Cabo--Brazil).

    PubMed

    Cuadrat, Rafael R C; Ferrera, Isabel; Grossart, Hans-Peter; Dávila, Alberto M R

    2016-02-01

    Marine habitats harbor a great diversity of microorganism from the three domains of life, only a small fraction of which can be cultivated. Metagenomic approaches are increasingly popular for addressing microbial diversity without culture, serving as sensitive and relatively unbiased methods for identifying and cataloging the diversity of nucleic acid sequences derived from organisms in environmental samples. Aerobic anoxygenic phototrophic bacteria (AAP) play important roles in carbon and energy cycling in aquatic systems. In oceans, those bacteria are widely distributed; however, their abundance and importance are still poorly understood. The aim of this study was to estimate abundance and diversity of AAPs in metagenomes from an upwelling affected coastal bay in Arraial do Cabo, Brazil, using in silico screening for the anoxygenic photosynthesis core genes. Metagenomes from the Global Ocean Sample Expedition (GOS) were screened for comparative purposes. AAPs were highly abundant in the free-living bacterial fraction from Arraial do Cabo: 23.88% of total bacterial cells, compared with 15% in the GOS dataset. Of the ten most AAP abundant samples from GOS, eight were collected close to the Equator where solar irradiation is high year-round. We were able to assign most retrieved sequences to phylo-groups, with a particularly high abundance of Roseobacter in Arraial do Cabo samples. The high abundance of AAP in this tropical bay may be related to the upwelling phenomenon and subsequent picoplankton bloom. These results suggest a link between upwelling and light abundance and demonstrate AAP even in oligotrophic tropical and subtropical environments. Longitudinal studies in the Arraial do Cabo region are warranted to understand the dynamics of AAP at different locations and seasons, and the ecological role of these unique bacteria for biogeochemical and energy cycling in the ocean. PMID:26871866

  4. [Anoxygenic phototrophic bacteria from microbial communities of Goryachinsk Thermal Spring (Baikal Area, Russia)].

    PubMed

    Kalashnikov, A M; Gaĭsin, V A; Sukhacheva, M V; Namsaraeva, B B; Panteleeva, A N; Nuianzina-Boldareva, E N; Kuznetsov, B B; Gorlenko, V M

    2014-01-01

    Species composition of anoxygenic phototrophic bacteria in microbial mats of the Goryachinsk thermal spring was investigated along the temperature gradient. The spring belonging to nitrogenous alkaline hydrotherms is located at the shore of Lake Baikal 188 km north-east from Ulan-Ude. The water is of the sulfate-sodium type, contains trace amounts of sulfide, salinity does not exceed 0.64 g/L, pH 9.5. The temperature at the outlet of the spring may reach 54 degrees C. The cultures of filamentous anoxygenic phototrophic bacteria, nonsulfur and sulfur purple bacteria, and aerobic anoxygenic phototrophic bacteria were identified using the pufLM molecular marker. The fmoA marker was used for identification of green sulfur bacteria. Filamentous cyanobacteria predominated in the mats, with anoxygenic phototrophs comprising a minor component of the phototrophic communities. Thermophilic bacteria Chloroflexus aurantiacus were detected irn the samples from both the thermophilic and mesophilic mats. Cultures ofnonsulfur purple bacteria similar to Blastochloris sulfoviridis and Rhodomicrobium vannielii were isolatd from the mats developing at high (50.6-49.4 degrees C) and low temperatures (45-20 degrees C). Purple sulfur bacteria Allochromatium sp. and Thiocapsa sp., as well as green sulfur bacteria Chlorobium sp., were revealedin low-temperature mats. Truly thermophilic purple and gree sulfur bacteria were not found in the spring. Anoxygenic phototrophic bacteria found in the spring were typical of the sulfuret communities, for which the sulfur cycle is mandatory. The presence of aerobic bacteriochlorophylla-containing bacteria identified as Agrobacterium (Rhizobium) tumifaciens in the mesophilic (20 degrees C) mat is of interest. PMID:25844460

  5. Complete Genome Sequence of the Filamentous Anoxygenic Phototrophic Bacterium Chloroflexus aurantiacus

    SciTech Connect

    Tang, Kuo-Hsiang; Barry, Kerrie; Chertkov, Olga; Dalin, Eileen; Han, Cliff; Hauser, Loren John; Honchak, Barbara M; Karbach, Lauren E; Land, Miriam L; Lapidus, Alla L.; Larimer, Frank W; Mikhailova, Natalia; Pitluck, Sam; Pierson, Beverly K

    2011-01-01

    Chloroflexus aurantiacus is a thermophilic filamentous anoxygenic phototrophic (FAP) bacterium, and can grow phototrophically under anaerobic conditions or chemotrophically under aerobic and dark conditions. According to 16S rRNA analysis, Chloroflexi species are the earliest branching bacteria capable of photosynthesis, and Cfl. aurantiacus has been long regarded as a key organism to resolve the obscurity of the origin and early evolution of photosynthesis. Cfl. aurantiacus contains a chimeric photosystem that comprises some characters of green sulfur bacteria and purple photosynthetic bacteria, and also has some unique electron transport proteins compared to other photosynthetic bacteria.

  6. The hydrological context determines the beta-diversity of aerobic anoxygenic phototrophic bacteria in European Arctic seas but does not favor endemism

    PubMed Central

    Lehours, Anne-Catherine; Jeanthon, Christian

    2015-01-01

    Despite an increasing number of studies over the last 15 years, aerobic anoxygenic photoheterotrophic (AAP) bacteria remain a puzzling functional group in terms of physiology, metabolism, and ecology. To contribute to a better knowledge of their environmental distribution, the present study aims at analyzing their diversity and structure at the boundary between the Norwegian, Greenland, and Barents Seas. The polymorphism of a marker gene encoding a sub-unit of the photosynthetic apparatus (pufM gene) was analyzed and attempted to be related to environmental parameters. The Atlantic or Arctic origin of water masses had a strong impact on the AAP bacterial community structure whose populations mostly belonged to the Alpha- and Gammaproteobacteria. A majority (>60%) of pufM sequences were affiliated to the Gammaproteobacteria reasserting that this class often represents the major component of the AAP bacterial community in oceanic regions. Two alphaproteobacterial groups dominate locally suggesting that they can constitute key players in this marine system transiently. We found that temperature is a major determinant of alpha diversity of AAP bacteria in this marine biome with specific clades emerging locally according to the partitioning of water masses. Whereas we expected specific AAP bacterial populations in this peculiar and newly explored ecosystem, most pufM sequences were highly related to sequences retrieved elsewhere. This observation highlights that the studied area does not favor AAP bacteria endemism but also opens new questions about the truthfulness of biogeographical patterns and on the extent of AAP bacterial diversity. PMID:26191046

  7. Complete genome sequence of the filamentous anoxygenic phototrophic bacterium Chloroflexus aurantiacus

    PubMed Central

    2011-01-01

    Background Chloroflexus aurantiacus is a thermophilic filamentous anoxygenic phototrophic (FAP) bacterium, and can grow phototrophically under anaerobic conditions or chemotrophically under aerobic and dark conditions. According to 16S rRNA analysis, Chloroflexi species are the earliest branching bacteria capable of photosynthesis, and Cfl. aurantiacus has been long regarded as a key organism to resolve the obscurity of the origin and early evolution of photosynthesis. Cfl. aurantiacus contains a chimeric photosystem that comprises some characters of green sulfur bacteria and purple photosynthetic bacteria, and also has some unique electron transport proteins compared to other photosynthetic bacteria. Methods The complete genomic sequence of Cfl. aurantiacus has been determined, analyzed and compared to the genomes of other photosynthetic bacteria. Results Abundant genomic evidence suggests that there have been numerous gene adaptations/replacements in Cfl. aurantiacus to facilitate life under both anaerobic and aerobic conditions, including duplicate genes and gene clusters for the alternative complex III (ACIII), auracyanin and NADH:quinone oxidoreductase; and several aerobic/anaerobic enzyme pairs in central carbon metabolism and tetrapyrroles and nucleic acids biosynthesis. Overall, genomic information is consistent with a high tolerance for oxygen that has been reported in the growth of Cfl. aurantiacus. Genes for the chimeric photosystem, photosynthetic electron transport chain, the 3-hydroxypropionate autotrophic carbon fixation cycle, CO2-anaplerotic pathways, glyoxylate cycle, and sulfur reduction pathway are present. The central carbon metabolism and sulfur assimilation pathways in Cfl. aurantiacus are discussed. Some features of the Cfl. aurantiacus genome are compared with those of the Roseiflexus castenholzii genome. Roseiflexus castenholzii is a recently characterized FAP bacterium and phylogenetically closely related to Cfl. aurantiacus. According to

  8. Unique communities of anoxygenic phototrophic bacteria in saline lakes of Salar de Atacama (Chile): evidence for a new phylogenetic lineage of phototrophic Gammaproteobacteria from pufLM gene analyses.

    PubMed

    Thiel, Vera; Tank, Marcus; Neulinger, Sven C; Gehrmann, Linda; Dorador, Cristina; Imhoff, Johannes F

    2010-12-01

    Phototrophic bacteria are important primary producers of salt lakes in the Salar de Atacama and at times form visible mass developments within and on top of the lake sediments. The communities of phototrophic bacteria from two of these lakes were characterized by molecular genetic approaches using key genes for the biosynthesis of the photosynthetic apparatus in phototrophic purple bacteria (pufLM) and in green sulfur bacteria (fmoA). Terminal restriction fragment length polymorphism of the pufLM genes indicated high variability of the community composition between the two lakes and subsamples thereof. The communities were characterized by the dominance of a novel, so far undescribed lineage of pufLM containing bacteria and the presence of representatives related to known halophilic Chromatiaceae and Ectothiorhodospiraceae. In addition, the presence of BChl b-containing anoxygenic phototrophic bacteria and of aerobic anoxygenic bacteria was indicated. Green sulfur bacteria were not detected in the environmental samples, although a bacterium related to Prosthecochloris indicum was identified in an enrichment culture. This is the first comprehensive description of phototrophic bacterial communities in a salt lake of South America made possible only due to the application of the functional pufLM genes. PMID:20868378

  9. Computation studies into architecture and energy transfer properties of photosynthetic units from filamentous anoxygenic phototrophs

    SciTech Connect

    Linnanto, Juha Matti; Freiberg, Arvi

    2014-10-06

    We have used different computational methods to study structural architecture, and light-harvesting and energy transfer properties of the photosynthetic unit of filamentous anoxygenic phototrophs. Due to the huge number of atoms in the photosynthetic unit, a combination of atomistic and coarse methods was used for electronic structure calculations. The calculations reveal that the light energy absorbed by the peripheral chlorosome antenna complex transfers efficiently via the baseplate and the core B808–866 antenna complexes to the reaction center complex, in general agreement with the present understanding of this complex system.

  10. Chemical and structural status of copper associated with oxygenic and anoxygenic phototrophs and heterotrophs: possible evolutionary consequences.

    PubMed

    Pokrovsky, O S; Pokrovski, G S; Shirokova, L S; Gonzalez, A G; Emnova, E E; Feurtet-Mazel, A

    2012-03-01

    Copper adsorption on the surface and intracellular uptake inside the cells of four representative taxons of soil and aquatic micro-organisms: aerobic rhizospheric heterotrophs (Pseudomonas aureofaciens), anoxygenic (Rhodovulum steppense) and oxygenic (cyanobacteria Gloeocapsa sp. and freshwater diatoms Navicula minima) phototrophs were studied in a wide range of pH, copper concentration, and time of exposure. Chemical status of adsorbed and assimilated Cu was investigated using in situ X-ray absorption spectroscopy. In case of adsorbed copper, XANES spectra demonstrated significant fractions of Cu(I) likely in the form of tri-coordinate complexes with O/N and/or S ligands. Upon short-term reversible adsorption at all four studied micro-organisms' cell surface, Cu(II) is coordinated by 4.0 ± 0.5 planar oxygens at an average distance of 1.97 ± 0.02 Å, which is tentatively assigned to the carboxylate groups. The atomic environment of copper incorporated into diatoms and cyanobacteria during long-term growth is similar to that of the adsorbed metal with slightly shorter distances to the first O/N neighbor (1.95 Å). In contrast to the common view of Cu status in phototrophic micro-organisms, XAFS failed to detect sulfur in the nearest atomic environment of Cu assimilated by freshwater plankton (cyanobacteria) and periphyton (diatoms). The appearance of S in Cu 1st coordination shell at 2.27-2.32 Å was revealed only after long-term interaction of Cu with anoxygenic phototrophs (and Cu uptake by soil heterotrophs), suggesting Cu scavenging in the form of sulfhydryl, histidine/carboxyl or a mixture of carboxylate and sulfhydryl complexes. These new structural constraints suggest that adsorbed Cu(II) is partially reduced to Cu(I) already at the cell surface, where as intracellular Cu uptake and storage occur in the form of both Cu(I)-S linked proteins and Cu(II) carboxylates. Obtained results allow to better understand how, in the course of biological evolution, micro

  11. Draft Genome Sequence of a Sulfide-Oxidizing, Autotrophic Filamentous Anoxygenic Phototrophic Bacterium, Chloroflexus sp. Strain MS-G (Chloroflexi).

    PubMed

    Thiel, Vera; Hamilton, Trinity L; Tomsho, Lynn P; Burhans, Richard; Gay, Scott E; Schuster, Stephan C; Ward, David M; Bryant, Donald A

    2014-01-01

    The draft genome sequence of the thermophilic filamentous anoxygenic phototrophic bacterium Chloroflexus sp. strain MS-G (Chloroflexi), isolated from Mushroom Spring (Yellowstone National Park, WY, USA) was sequenced and comprises 4,784,183 bp in 251 contigs. The draft genome is predicted to encode 4,059 protein coding genes, 49 tRNA encoding genes, and 3 rRNA operons. PMID:25189583

  12. Draft Genome Sequence of a Sulfide-Oxidizing, Autotrophic Filamentous Anoxygenic Phototrophic Bacterium, Chloroflexus sp. Strain MS-G (Chloroflexi)

    PubMed Central

    Thiel, Vera; Hamilton, Trinity L.; Tomsho, Lynn P.; Burhans, Richard; Gay, Scott E.; Schuster, Stephan C.; Ward, David M.

    2014-01-01

    The draft genome sequence of the thermophilic filamentous anoxygenic phototrophic bacterium Chloroflexus sp. strain MS-G (Chloroflexi), isolated from Mushroom Spring (Yellowstone National Park, WY, USA) was sequenced and comprises 4,784,183 bp in 251 contigs. The draft genome is predicted to encode 4,059 protein coding genes, 49 tRNA encoding genes, and 3 rRNA operons. PMID:25189583

  13. Oxygen and sulfur isotope fractionation during sulfide oxidation by anoxygenic phototrophic bacteria

    NASA Astrophysics Data System (ADS)

    Brabec, Michelle Y.; Lyons, Timothy W.; Mandernack, Kevin W.

    2012-04-01

    Sulfide-mediated anoxygenic photosynthesis (SMAP) carried out by anaerobic phototrophic bacteria may have played an important role in sulfur cycling, formation of sulfate, and, perhaps, primary production in the Earth’s early oceans. Determination of ε34SSO4-Sulfide- and ε18OSO4-H2O values for bacterial sulfide oxidation will permit more refined interpretation of the δ34S and δ18OSO4 values measured in modern anoxic environments, such as meromictic lakes where sulfide commonly extends into the photic zone, and in the ancient rock record, particularly during periods of the Precambrian when anoxic and sulfidic (euxinic) conditions were believed to be more pervasive than today. Laboratory experiments with anaerobic purple and green sulfur phototrophs, Allochromatium vinosum and Chlorobaculum tepidum, respectively, were conducted to determine the sulfur and oxygen isotope fractionation during the oxidation of sulfide to sulfate. Replicate experiments were conducted at 25 °C for A. vinosum and 45 °C for C. tepidum, and in duplicate at three different starting oxygen isotope values for water to determine sulfate-water oxygen isotope fractionations accurately (ε18OSO4-H2O). ε18OSO4-H2O values of 5.6 ± 0.2‰ and 5.4 ± 0.1‰ were obtained for A. vinosum and C. tepidum, respectively. Temperature had no apparent effect on the ε18OSO4-H2O values. By combining all data from both cultures, an average ε18OSO4-H2O value of 5.6 ± 0.3‰ was obtained for SMAP. This value falls between those previously reported for bacterial oxidation of sphalerite and elemental sulfur (7-9‰) and abiotic and biotic oxidation of pyrite and chalcopyrite (2-4‰). Sulfur isotope fractionation between sulfide and sulfate formed by A.vinosum was negligible (0.1 ± 0.2‰) during all experiments. For C. tepidum an apparent fractionation of -2.3 ± 0.5‰ was observed during the earlier stages of oxidation based on bulk δ34S measurements of sulfate and sulfide and became smaller (-0.7

  14. Draft Genome Sequence of Chloroflexus sp. Strain isl-2, a Thermophilic Filamentous Anoxygenic Phototrophic Bacterium Isolated from the Strokkur Geyser, Iceland.

    PubMed

    Gaisin, Vasil A; Ivanov, Timophey M; Kuznetsov, Boris B; Gorlenko, Vladimir M; Grouzdev, Denis S

    2016-01-01

    We report here the draft genome sequence of the thermophilic filamentous anoxygenic phototrophic bacterium Chloroflexus sp. strain isl-2, which was isolated from the Strokkur geyser, Iceland, and contains 5,222,563 bp with a G+C content of 59.65%. The annotated genome sequence offers the genetic basis for understanding the strain's ecological role as a phototrophic bacterium within the bacterial community. PMID:27445390

  15. Draft Genome Sequence of Chloroflexus sp. Strain isl-2, a Thermophilic Filamentous Anoxygenic Phototrophic Bacterium Isolated from the Strokkur Geyser, Iceland

    PubMed Central

    Gaisin, Vasil A.; Ivanov, Timophey M.; Kuznetsov, Boris B.; Gorlenko, Vladimir M.

    2016-01-01

    We report here the draft genome sequence of the thermophilic filamentous anoxygenic phototrophic bacterium Chloroflexus sp. strain isl-2, which was isolated from the Strokkur geyser, Iceland, and contains 5,222,563 bp with a G+C content of 59.65%. The annotated genome sequence offers the genetic basis for understanding the strain’s ecological role as a phototrophic bacterium within the bacterial community. PMID:27445390

  16. Formation of the light-harvesting complex I (B870) of anoxygenic phototrophic purple bacteria.

    PubMed

    Drews, G

    1996-09-01

    The light-harvesting (LH) complex I (B870) of anoxygenic photosynthetic purple bacteria is the oligomeric form of its subunit B820 consisting of the low-molecular-weight polypeptides alpha, beta, bacteriochlorophyll (BChl), and carotenoids in the stoichiometric ratio [alpha1 beta1 (BChl2) Crt1-2]n. LHI surrounds the photochemical reaction center (RC). The major absorption band of the LHI complex is species-specific and is found at 870-890 nm; those of the subunit and the monomeric BChl a (dissolved in methanol) absorb at 820 and 770 nm, respectively. The isolated LHI complex can be reversibly dissociated to the B820 subunit or to the polypeptides and pigments by addition of detergents. Reconstitution of the B820 or the functional B870 complex is still possible after partial truncation of the N- or C-terminal regions of the alpha- or beta-polypeptide or of the beta-polypeptide only. The minimal structural requirements for reconstitution of a spectrally wild-type form after truncation of the polypeptides and/or modifications of the BChl molecule are described. The insertion of the LHIalpha- and LHIbeta-polypeptides into the membrane and the in vivo assembly of LHI, studied in a cell-free system and in whole cells of Rhodobacter capsulatus, depend on the primary structures of both polypeptides, BChl, the chaperones DnaK and GroEL, membrane-bound proteins, and energized membranes. Exchanges, deletions, or insertions of amino acyl residues, especially in the conserved region of the N-terminus of the LHIalpha-polypeptide, prevent or reduce the efficiency and stability of the LHI assembly. Therefore, reconstitution of LHI in a detergent micelle does not exactly reproduce the formation of the LHI complex in the photosynthetic membrane in vivo. The N-terminal domains play a crucial role in the formation of the oligomeric protein scaffold and of the pigment array. Facultatively phototrophic bacteria such as Rhodospirillum (Rsp.) rubrum or Rhodobacter (Rba.) capsulatus can

  17. Functional Relationship Between Phytoplankton and Aerobic Anoxygenic Photosynthetic Bacteria: Modes of Coexistence

    NASA Astrophysics Data System (ADS)

    Kolber, Z. S.; Haffa, A.; Klimov, D.

    2006-12-01

    Aerobic Anoxygenic Photosynthetic Bacteria (AAPs) are ubiquitously distributed in the upper ocean. Although they contain bacteriochlorophyll a (BChla), the main absorption bands in the near UV (370 nm) and infrared (800-850 nm) make this pigment impractical in light harvesting below the first few meters of the water column. Instead, they utilize carotenoids as major light harvesting pigments. Since these carotenoids absorb in the 430-550 nm range, phytoplankton and AAPs utilize a similar portion of the available light spectrum. As AAPs cannot utilize water as the electron donor, they transfer electrons between a range of organic/inorganic electron donors and electron acceptors, thus significantly participating in the redox cycle in the upper ocean. We have measured the vertical distribution and photosynthetic properties of both phytoplankton and AAPs in a highly oligotrophic region 800 km SW of Monterey Bay (34N, 129W), and we have consistently observed the presence of a BChla maximum about 30 to 40 meters above the chlorophyll maximum, indicating that phytoplankton and AAPs occupy different ecological niches in the water column. However, the abundance of AAPs generally displayed a maximum at dawn and a minimum at the dusk, indicating a high level of mortality. This diel cycle was observed in 5 micron and 3 micron size fractions, indicating active grazing by small protists. Incubation experiments with natural, mixed population of AAPs and phytoplankton results in an unusually high accumulation of AAPs in DCMU-treated samples, indicating that pigmented protists do contribute significantly to AAP grazing in a tightly-controlled microbial loop. On the other hand, AAP incubations in pure cultures indicate that they biomineralize sulfur, thus affecting the sulfur cycle. All of these observations indicate that the role of AAPs in the upper ocean ecology is defined by their relationship with phototrophic and heterotrophic communities, rather than by their relative

  18. Characterization of the chlorosome antenna of the filamentous anoxygenic phototrophic bacterium Chloronema sp. strain UdG9001.

    PubMed

    Gich, Frederic; Airs, Ruth L; Danielsen, Marianne; Keely, Brendan J; Abella, Carles A; Garcia-Gil, Jesús; Miller, Mette; Borrego, Carles M

    2003-12-01

    The absorption and fluorescence properties of chlorosomes of the filamentous anoxygenic phototrophic bacterium Chloronema sp. strain UdG9001 were analyzed. The chlorosome antenna of Chloronema consists of bacteriochlorophyll (BChl) d and BChl c together with gamma-carotene as the main carotenoid. HPLC analysis combined with APCI LC-MS/MS showed that the chlorosomal BChls comprise a highly diverse array of homologues that differ in both the degree of alkylation of the macrocycle at C-8 and/or C-12 and the alcohol moiety esterified to the propionic acid group at C-17. BChl c and BChl d from Chloronema were mainly esterified with geranylgeraniol (33% of the total), heptadecanol (24%), octadecenol (19%), octadecanol (14%), and hexadecenol (9%). Despite this pigment heterogeneity, fluorescence emission of the chlorosomes showed a single peak centered at 765 nm upon excitation at wavelengths ranging from 710 to 740 nm. This single emission, assigned to BChl c, indicates an energy transfer from BChl d to BChl c within the same chlorosome. Likewise, incubation of chlorosomes under reducing conditions caused a weak increase in fluorescence emission, which indicates a small redox-dependent fluorescence. Finally, protein analysis of Chloronema chlorosomes using SDS-PAGE and MALDI-TOF-MS revealed the presence of a chlorosomal polypeptide with a molecular mass of 5.7 kDa, resembling the CsmA protein found in Chloroflexus aurantiacus and Chlorobium tepidum chlorosomes. Several minor polypeptides were also detected but not identified. These results indicate that, compared with other members of filamentous anoxygenic phototrophic bacteria and green sulfur bacteria, Chloronema possesses an antenna system with novel features that may be of interest for further investigations. PMID:14610639

  19. Exciton description of chlorosome to baseplate excitation energy transfer in filamentous anoxygenic phototrophs and green sulfur bacteria.

    PubMed

    Linnanto, Juha M; Korppi-Tommola, Jouko E I

    2013-09-26

    A description of intra-chlorosome and from chlorosome to baseplate excitation energy transfer in green sulfur bacteria and in filamentous anoxygenic phototrophs is presented. Various shapes and sizes, single and multiwalled tubes, cylindrical spirals and lamellae of the antenna elements mimicking pigment organization in chlorosomes were generated by using molecular mechanics calculations, and the absorption, LD, and CD spectra of these were predicted by using exciton theory. Calculated absorption and LD spectra were similar for all modeled antenna structures; on the contrary, CD spectra turned out to be sensitive to the size and pigment orientations in the antenna. It was observed that, bringing two tubular antennae at close enough interaction distance, the exciton density of the lowest energy state became localized on pigments facing each other in the antenna dimer. Calculations predicted for stacked tubular antenna elements extremely fast, faster than 500 fs, intra-chlorosome energy transfer toward the baseplates in the direction perpendicular to the chlorosome long axis. Downhill excitation energy transfer according to our model is driven by interactions of the antennae with their immediate surroundings. Energy transfer from the chlorosome to the baseplate, consisting of 2D lattices of monomeric and dimeric bacteriochlorophyll a molecules, was predicted to occur in 5-15 ps, in agreement with experimental findings. Advancement of excitation through a double tube antenna stack, a model for antenna element organization in chlorosomes of green sulfur bacteria, to a monomeric baseplate was visualized in space and in time. PMID:23848459

  20. Carotenoid biomarkers as an imperfect reflection of the anoxygenic phototrophic community in meromictic Fayetteville Green Lake.

    PubMed

    Meyer, K M; Macalady, J L; Fulton, J M; Kump, L R; Schaperdoth, I; Freeman, K H

    2011-07-01

    Organic biomarkers in marine sedimentary rocks hold important clues about the early history of Earth's surface environment. The chemical relicts of carotenoids from anoxygenic sulfur bacteria are of particular interest to geoscientists because of their potential to signal episodes of marine photic-zone euxinia such as those proposed for extended periods in the Proterozoic as well as brief intervals during the Phanerozoic. It is therefore critical to constrain the environmental and physiological factors that influence carotenoid production and preservation in modern environments. Here, we present the results of coupled pigment and nucleic acid clone library analyses from planktonic and benthic samples collected from a microbially dominated meromictic lake, Fayetteville Green Lake (New York). Purple sulfur bacteria (PSB) are abundant and diverse both in the water column at the chemocline and in benthic mats below oxygenated shallow waters, with different PSB species inhabiting the two environments. Okenone (from PSB) is an abundant carotenoid in both the chemocline waters and in benthic mats. Green sulfur bacteria and their primary pigment Bchl e are also represented in and below the chemocline. However, the water column and sediments are devoid of the green sulfur bacteria carotenoid isorenieratene. The unexpected absence of isorenieratene and apparent benthic production of okenone provide strong rationale for continued exploration of the microbial ecology of biomarker production in modern euxinic environments. PMID:21682840

  1. Characterization of the physiology and cell-mineral interactions of the marine anoxygenic phototrophic Fe(II) oxidizer Rhodovulum iodosum--implications for Precambrian Fe(II) oxidation.

    PubMed

    Wu, Wenfang; Swanner, Elizabeth D; Hao, Likai; Zeitvogel, Fabian; Obst, Martin; Pan, Yongxin; Kappler, Andreas

    2014-06-01

    Anoxygenic phototrophic Fe(II)-oxidizing bacteria (photoferrotrophs) are suggested to have contributed to the deposition of banded iron formations (BIFs) from oxygen-poor seawater. However, most studies evaluating the contribution of photoferrotrophs to Precambrian Fe(II) oxidation have used freshwater and not marine strains. Therefore, we investigated the physiology and mineral products of Fe(II) oxidation by the marine photoferrotroph Rhodovulum iodosum. Poorly crystalline Fe(III) minerals formed initially and transformed to more crystalline goethite over time. During Fe(II) oxidation, cell surfaces were largely free of minerals. Instead, the minerals were co-localized with EPS suggesting that EPS plays a critical role in preventing cell encrustation, likely by binding Fe(III) and directing precipitation away from cell surfaces. Fe(II) oxidation rates increased with increasing initial Fe(II) concentration (0.43-4.07 mM) under a light intensity of 12 μmol quanta m(-2) s(-1). Rates also increased as light intensity increased (from 3 to 20 μmol quanta m(-2) s(-1)), while the addition of Si did not significantly change Fe(II) oxidation rates. These results elaborate on how the physical and chemical conditions present in the Precambrian ocean controlled the activity of marine photoferrotrophs and confirm the possibility that such microorganisms could have oxidized Fe(II), generating the primary Fe(III) minerals that were then deposited to some Precambrian BIFs. PMID:24606418

  2. Dynamics of the anoxygenic phototrophic community in meromictic Fayetteville Green Lake (NY) and the associated sedimentary pigment record

    NASA Astrophysics Data System (ADS)

    Meyer, K. M.; Fulton, J. M.; Hunter, S.; Macalady, J. L.; Kump, L.; Freeman, K. H.

    2012-12-01

    Photosynthetic pigments and their diagenetic products in marine sedimentary rocks hold important clues about recent and ancient variability in the Earth's surface environment. The chemical relicts of carotenoids from anoxygenic sulfur bacteria are of particular interest to geoscientists because of their potential to signal episodes of marine photic-zone euxinia such as those proposed for extended periods in the Proterozoic as well as brief intervals during the Phanerozoic. It is therefore critical to constrain the environmental and physiological factors that influence carotenoid production and preservation in modern environments. Our work in redox stratified, microbially dominated Fayetteville Green Lake (New York) has spanned the past decade and included seasonal (2005-2006) and monthly (2011) pigment monitoring in the water column, as well as a coupled pigment and nucleic acid clone library analyses from planktonic and benthic samples in 2006. Populations of photosynthetic bacteria in the water column are dynamic on monthly and annual scales. In 2011, purple sulfur bacteria (PSB) and green sulfur bacteria (GSB) were most abundant in spring and fall, respectively, responding to environmental conditions. PSB are diverse both at the chemocline and in benthic mats below oxygenated shallow waters, with different PSB species inhabiting the two environments. Okenone (from PSB) is an abundant carotenoid in both the chemocline waters and in benthic mats. GSB and their primary pigment Bchl e are also represented in and below the chemocline. However, the water column and sediments contain only trace concentrations of the GSB carotenoid isorenieratene, with concentrations relative to Bchl e being at least two orders of magnitude lower than we have observed in other meromictic lakes. Sediments deposited over the past ~550 years also reveal decadal to centennial scale variability in pigment production in the water column, possibly associated with hypothesized climatic and

  3. Isolation of Aerobic Anoxygenic Photosynthetic Bacteria from Black Smoker Plume Waters of the Juan de Fuca Ridge in the Pacific Ocean

    PubMed Central

    Yurkov, Vladimir; Beatty, J. Thomas

    1998-01-01

    A strain of the aerobic anoxygenic photosynthetic bacteria was isolated from a deep-ocean hydrothermal vent plume environment. The in vivo absorption spectra of cells indicate the presence of bacteriochlorophyll a incorporated into light-harvesting complex I and a reaction center. The general morphological and physiological characteristics of this new isolate are described. PMID:16349490

  4. Geminicoccus roseus gen. nov., sp. nov., an aerobic phototrophic Alphaproteobacterium isolated from a marine aquaculture biofilter.

    PubMed

    Foesel, Bärbel U; Gössner, Anita S; Drake, Harold L; Schramm, Andreas

    2007-12-01

    A Gram-negative, strictly aerobic, diplococcoid bacterium (strain D2-3(T)) was isolated from the biofilter of a recirculating marine aquaculture system. Phylogenetic analysis of the 16S rRNA gene sequence of D2-3(T) indicated that the new organism occupied a novel lineage within the alpha-1 subclass of Proteobacteria and was related to the genera Rhodothalassium, Azospirillum, Craurococcus, Acidiphilium, and Tistrella. The highest sequence similarity (90.8%) of the 16S rRNA gene sequence of D2-3(T) was to that of Candidatus "Alysiosphaera europaea". D2-3(T) was mesophilic, heterotrophic, required sea salt, and had a pH optimum of 8.0. Growth in the presence of light resulted in the formation of pink colonies, a 25% increased cell yield, and a slightly increased growth rate. D2-3(T) contained carotenoids and low amounts of bacteriochlorophyll a. Membranes of D2-3(T) contained b-type cytochromes. The G+C content of the DNA was 60.3+/-0.1mol%. Phylogenetic, morphological, physiological, and biochemical analyses demonstrated that D2-3(T) represented a new aerobic phototrophic genus, for which the name Geminicoccus roseus gen. nov., sp. nov. is proposed for the type species (D2-3(T)=DSM 18922(T)=ATCC BAA-1445(T)). PMID:17643894

  5. Hoeflea olei sp. nov., a diesel-oil-degrading, anoxygenic, phototrophic bacterium isolated from backwaters and emended description of the genus Hoeflea.

    PubMed

    Rahul, K; Azmatunnisa, M; Sasikala, Ch; Ramana, Ch V

    2015-08-01

    A Gram-stain-negative, diesel-oil-degrading, rod-shaped bacterium (designated JC234T) was isolated from a water sample collected from diesel-oil-contaminated backwaters in Kerala, India. Strain JC234T was oxidase- and catalase-positive, and grew at 20-35 °C and at pH 7-9. Cells contained bacteriochlorophyll-a, hydroxydemethylspheroidene and three unidentified carotenoids. Growth occurred under aerobic, microaerobic and phototrophic anaerobic conditions. Strain JC234T could utilize diesel-oil as a sole source of carbon and energy. Based on the 16S rRNA gene sequence analysis, strain JC234T belonged to the genus Hoeflea within the family Phyllobacteriaceae, and was closely related to Hoeflea alexandrii AM1V30T (98.1% 16S rRNA gene sequence similarity), Hoeflea halophila JG120-1T (97.6%) and other members of the genus Hoeflea ( < 96.4 ). Strain JC234T showed 22 ± 2% and 28 ± 1.5 % DNA-DNA hybridization with Hoeflea alexandrii KCTC 22096T and Hoeflea halophila KCTC 23107T, respectively. The DNA G+C content of strain JC234T was 54.3 mol %. The major cellular fatty acids were C18 : 1ω7c/C18 : 1ω6c, C16 : 0 and C16 : 1ω7c/C16 : 1ω6c. Phosphatidylcholine, phosphatidylethanolamine, phosphatidylmonomethylethanolamine and phosphatidylglycerol were the major polar lipids. Strain JC234T contained Q10 as the predominant ubiquinone. On the basis of morphological, physiological, genetic, phylogenetic and chemotaxonomical analyses, we conclude that strain JC234T represents a novel species of the genus Hoeflea, for which the name Hoefleaolei sp. nov. is proposed. The type strain is JC234T ( = KCTC 42071T = LMG 28200T). An emended description of the genus Hoeflea is also provided. PMID:25899504

  6. Citrimicrobium luteum gen. nov., sp. nov., aerobic anoxygenic phototrophic bacterium isolated from the gut of a sea cucumber Stichopus japonicus.

    PubMed

    Jung, Hong-Joo; Cha, In-Tae; Yim, Kyung June; Song, Hye Seon; Cho, Kichul; Kim, Daekyung; Lee, Hae-Won; Lee, Jae Kook; Seo, Myung-Ji; Roh, Seong Woon; Lee, Sung-Jae

    2014-10-01

    A Gram-stain negative, yellow-pigmented, motile, pleomorphic bacterium, designated strain CBA4602(T), was isolated from the gut of the sea cucumber Stichopus japonicus, which was collected from Jeju Island in the Republic of Korea. In a phylogenetic analysis based on the 16S rRNA gene, strain CBA4602(T) belonged to the order Sphingomonadales in the class Alphaproteobacteria. The 16S rRNA gene sequence similarity between strain CBA4602(T) and 'Citromicrobium bathyomarinum' JF-1, the most closely related strain having nonvalidly published name, was 98.4%, followed by 95.2-96.7% identities with sequence of the other closest strains in the genus Erythrobacter. Strain CBA4602(T) had bacteriochlorophyll a and carotenoids. Strain CBA4602(T) grew in 0-10% (w/v) NaCl, at 10-42°C and pH 6.0-8.0, with optimal growth in 1-2% NaCl, at 30-37°C and pH 7.0. Strain CBA4602(T) was positive for catalase and oxidase activities and was able to hydrolyse gelatine and Tween 20 and 40, but not starch, Tween 80 or L-tyrosine. The G+C content of genomic DNA from strain CBA4602(T) was 68.0 mol% and Q-10 was the major detected isoprenoid quinone. The polar lipids were three unidentified phospholipids, three unidentified glycolipids, and two unidentified lipids. The dominant fatty acids were anteiso-C15:0, C16:0, anteiso-C17:0 and C18:0. As considering the current taxonomic status of the genus 'Citromicrobium' and polyphasic taxonomic analyses, strain CBA4602(T) represents a novel genus and species. The name Citrimicrobium luteum is proposed for the type strain CBA4602(T) (=KACC 17668(T) =JCM 19530(T)). PMID:25163838

  7. A Comparison of 14 Erythrobacter Genomes Provides Insights into the Genomic Divergence and Scattered Distribution of Phototrophs

    PubMed Central

    Zheng, Qiang; Lin, Wenxin; Liu, Yanting; Chen, Chang; Jiao, Nianzhi

    2016-01-01

    Aerobic anoxygenic phototrophic bacteria (AAPB) are bacteriochlorophyll a (Bchl a)-containing microbial functional population. Erythrobacter is the first genus that was identified to contain AAPB species. Here, we compared 14 Erythrobacter genomes: seven phototrophic strains and seven non- phototrophic strains. Interestingly, AAPB strains are scattered in this genus based on their phylogenetic relationships. All 14 strains could be clustered into three groups based on phylo-genomic analysis, average genomic nucleotide identity and the phylogeny of signature genes (16S rRNA and virB4 genes). The AAPB strains were distributed in three groups, and gain and loss of phototrophic genes co-occurred in the evolutionary history of the genus Erythrobacter. The organization and structure of photosynthesis gene clusters (PGCs) in seven AAPB genomes displayed high synteny of major regions except for few insertions. The 14 Erythrobacter genomes had a large range of genome sizes, from 2.72 to 3.60 M, and the sizes of the core and pan- genomes were 1231 and 8170 orthologous clusters, respectively. Integrative and conjugative elements (ICEs) were frequently identified in genomes we studied, which might play significant roles in shaping or contributing to the pan-genome of Erythrobacter. Our findings suggest the ongoing evolutionary divergence of Erythrobacter genomes and the scattered distribution characteristic of PGC. PMID:27446024

  8. A Comparison of 14 Erythrobacter Genomes Provides Insights into the Genomic Divergence and Scattered Distribution of Phototrophs.

    PubMed

    Zheng, Qiang; Lin, Wenxin; Liu, Yanting; Chen, Chang; Jiao, Nianzhi

    2016-01-01

    Aerobic anoxygenic phototrophic bacteria (AAPB) are bacteriochlorophyll a (Bchl a)-containing microbial functional population. Erythrobacter is the first genus that was identified to contain AAPB species. Here, we compared 14 Erythrobacter genomes: seven phototrophic strains and seven non- phototrophic strains. Interestingly, AAPB strains are scattered in this genus based on their phylogenetic relationships. All 14 strains could be clustered into three groups based on phylo-genomic analysis, average genomic nucleotide identity and the phylogeny of signature genes (16S rRNA and virB4 genes). The AAPB strains were distributed in three groups, and gain and loss of phototrophic genes co-occurred in the evolutionary history of the genus Erythrobacter. The organization and structure of photosynthesis gene clusters (PGCs) in seven AAPB genomes displayed high synteny of major regions except for few insertions. The 14 Erythrobacter genomes had a large range of genome sizes, from 2.72 to 3.60 M, and the sizes of the core and pan- genomes were 1231 and 8170 orthologous clusters, respectively. Integrative and conjugative elements (ICEs) were frequently identified in genomes we studied, which might play significant roles in shaping or contributing to the pan-genome of Erythrobacter. Our findings suggest the ongoing evolutionary divergence of Erythrobacter genomes and the scattered distribution characteristic of PGC. PMID:27446024

  9. Genome sequence of Fulvimarina pelagi HTCC2506T, a Mn(II)-oxidizing alphaproteobacterium possessing an aerobic anoxygenic photosynthetic gene cluster and Xanthorhodopsin.

    PubMed

    Kang, Ilnam; Oh, Hyun-Myung; Lim, Seung-Il; Ferriera, Steve; Giovannoni, Stephen J; Cho, Jang-Cheon

    2010-09-01

    Fulvimarina pelagi is a Mn(II)-oxidizing marine heterotrophic bacterium in the order Rhizobiales. Here we announce the draft genome sequence of F. pelagi HTCC2506(T), which was isolated from the Sargasso Sea by using dilution-to-extinction culturing. The genome sequence contained a xanthorhodopsin gene as well as a photosynthetic gene cluster, which suggests the coexistence of two different phototrophic mechanisms in a single microorganism. PMID:20639329

  10. Phototrophic Fe(II)-oxidation in the chemocline of a ferruginous meromictic lake

    PubMed Central

    Walter, Xavier A.; Picazo, Antonio; Miracle, Maria R.; Vicente, Eduardo; Camacho, Antonio; Aragno, Michel; Zopfi, Jakob

    2014-01-01

    Precambrian Banded Iron Formation (BIF) deposition was conventionally attributed to the precipitation of iron-oxides resulting from the abiotic reaction of ferrous iron (Fe(II)) with photosynthetically produced oxygen. Earliest traces of oxygen date from 2.7 Ga, thus raising questions as to what may have caused BIF precipitation before oxygenic photosynthesis evolved. The discovery of anoxygenic phototrophic bacteria thriving through the oxidation of Fe(II) has provided support for a biological origin for some BIFs, but despite reports suggesting that anoxygenic phototrophs may oxidize Fe(II) in the environment, a model ecosystem of an ancient ocean where they are demonstrably active was lacking. Here we show that anoxygenic phototrophic bacteria contribute to Fe(II) oxidation in the water column of the ferruginous sulfate-poor, meromictic lake La Cruz (Spain). We observed in-situ photoferrotrophic activity through stimulation of phototrophic carbon uptake in the presence of Fe(II), and determined light-dependent Fe(II)-oxidation by the natural chemocline microbiota. Moreover, a photoferrotrophic bacterium most closely related to Chlorobium ferrooxidans was enriched from the ferruginous water column. Our study for the first time demonstrates a direct link between anoxygenic photoferrotrophy and the anoxic precipitation of Fe(III)-oxides in a ferruginous water column, providing a plausible mechanism for the bacterial origin of BIFs before the advent of free oxygen. However, photoferrotrophs represent only a minor fraction of the anoxygenic phototrophic community with the majority apparently thriving by sulfur cycling, despite the very low sulfur content in the ferruginous chemocline of Lake La Cruz. PMID:25538702

  11. Phototrophic Fe(II)-oxidation in the chemocline of a ferruginous meromictic lake.

    PubMed

    Walter, Xavier A; Picazo, Antonio; Miracle, Maria R; Vicente, Eduardo; Camacho, Antonio; Aragno, Michel; Zopfi, Jakob

    2014-01-01

    Precambrian Banded Iron Formation (BIF) deposition was conventionally attributed to the precipitation of iron-oxides resulting from the abiotic reaction of ferrous iron (Fe(II)) with photosynthetically produced oxygen. Earliest traces of oxygen date from 2.7 Ga, thus raising questions as to what may have caused BIF precipitation before oxygenic photosynthesis evolved. The discovery of anoxygenic phototrophic bacteria thriving through the oxidation of Fe(II) has provided support for a biological origin for some BIFs, but despite reports suggesting that anoxygenic phototrophs may oxidize Fe(II) in the environment, a model ecosystem of an ancient ocean where they are demonstrably active was lacking. Here we show that anoxygenic phototrophic bacteria contribute to Fe(II) oxidation in the water column of the ferruginous sulfate-poor, meromictic lake La Cruz (Spain). We observed in-situ photoferrotrophic activity through stimulation of phototrophic carbon uptake in the presence of Fe(II), and determined light-dependent Fe(II)-oxidation by the natural chemocline microbiota. Moreover, a photoferrotrophic bacterium most closely related to Chlorobium ferrooxidans was enriched from the ferruginous water column. Our study for the first time demonstrates a direct link between anoxygenic photoferrotrophy and the anoxic precipitation of Fe(III)-oxides in a ferruginous water column, providing a plausible mechanism for the bacterial origin of BIFs before the advent of free oxygen. However, photoferrotrophs represent only a minor fraction of the anoxygenic phototrophic community with the majority apparently thriving by sulfur cycling, despite the very low sulfur content in the ferruginous chemocline of Lake La Cruz. PMID:25538702

  12. Distribution and Origin of Oxygen-Dependent and Oxygen-Independent Forms of Mg-Protoporphyrin Monomethylester Cyclase among Phototrophic Proteobacteria

    PubMed Central

    Boldareva-Nuianzina, Ekaterina N.; Bláhová, Zuzana; Sobotka, Roman

    2013-01-01

    Magnesium-protoporphyrin IX monomethylester cyclase is one of the key enzymes of the bacteriochlorophyll biosynthesis pathway. There exist two fundamentally different forms of this enzyme. The oxygen-dependent form, encoded by the gene acsF, catalyzes the formation of the bacteriochlorophyll fifth ring using oxygen, whereas the oxygen-independent form encoded by the gene bchE utilizes an oxygen atom extracted from water. The presence of acsF and bchE genes was surveyed in various phototrophic Proteobacteria using the available genomic data and newly designed degenerated primers. It was found that while the majority of purple nonsulfur bacteria contained both forms of the cyclase, the purple sulfur bacteria contained only the oxygen-independent form. All tested species of aerobic anoxygenic phototrophs contained acsF genes, but some of them also retained the bchE gene. In contrast to bchE phylogeny, the acsF phylogeny was in good agreement with 16S inferred phylogeny. Moreover, the survey of the genome data documented that the acsF gene occupies a conserved position inside the photosynthesis gene cluster, whereas the bchE location in the genome varied largely between the species. This suggests that the oxygen-dependent cyclase was recruited by purple phototrophic bacteria very early during their evolution. The primary sequence and immunochemical similarity with its cyanobacterial counterparts suggests that acsF may have been acquired by Proteobacteria via horizontal gene transfer from cyanobacteria. The acquisition of the gene allowed purple nonsulfur phototrophic bacteria to proliferate in the mildly oxygenated conditions of the Proterozoic era. PMID:23396335

  13. Facultative anoxygenic photosynthesis in cyanobacteria driven by arsenite and sulfide with evidence for the support of nitrogen fixation

    NASA Astrophysics Data System (ADS)

    Wolfe-Simon, F.; Hoeft, S. E.; Baesman, S. M.; Oremland, R. S.

    2010-12-01

    The rise in atmospheric oxygen (O2) over geologic time is attributed to the evolution and widespread proliferation of oxygenic photosynthesis in cyanobacteria. However, cyanobacteria maintain a metabolic flexibility that may not always result in O2 release. In the environment, cyanobacteria may use a variety of alternative electron donors rather than water that are known to be used by other anoxygenic phototrophs (eg. purple sulfur bacteria) including reduced forms of sulfur, iron, nitrogen, and arsenic. Recent evidence suggests cyanobacteria actively take advantage of at least a few of these alternatives. We used a classical Winogradsky approach to enrich for cyanobacteria from the high salinity, elevated pH and arsenic-enriched waters of Mono Lake (CA). Experiments, optimized for cyanobacteria, revealed light-dependent, anaerobic arsenite-oxidation in sub-cultured sediment-free enrichments dominated by a filamentous cyanobacteria. We isolated and identified the dominant member of this enrichment to be a member of the Oscillatoriales by 16S rDNA. Addition of 1 mM arsenite induced facultative anoxygenic photosynthesis under continuous and circadian light. This isolate also oxidized sulfide under the same light-based conditions. Aerobic conditions elicited no arsenite oxidation in the light or dark and the isolate grew as a typical cyanobacterium using oxygenic photosynthesis. Under near-infrared light (700 nm) there was a direct correlation of enhanced growth with an increase in the rate arsenite or sulfide oxidation suggesting the use of photosystem I. Additionally, to test the wide-spread nature of this metabolism in the Oscillatoriales, we followed similar arsenite- and sulfide-driven facultative anoxygenic photosynthesis as well as nitrogen fixation (C2H2 reduction) in the axenic isolate Oscillatoria sp. CCMP 1731. Future characterization includes axenic isolation of the Mono Lake Oscillatoria sp. as well as the arsenite oxidase responsible for electron

  14. Occurrence of facultative anoxygenic photosynthesis among filamentous and unicellular cyanobacteria.

    PubMed Central

    Garlick, S; Oren, A; Padan, E

    1977-01-01

    Eleven of 21 cyanobacteria strains examined are capable of facultative anoxygenic photosynthesis, as shown by their ability to photoassimilate CO2 in the presence of Na2S, 3-(3,4-dichlorophenyl)-1,1-dimethylurea and 703-nm light. These include different cyanobacterial types (filamentous and unicellular) of different growth histories (aerobic, anaerobic, and marine and freshwater). Oscillatoria limnetica, Aphanothece halophytica (7418), and Lyngbya (7104) have different optimal concentrations of Na2S permitting CO2 photoassimilation, above which the rate decreases: 3.5, 0.7, and 0.1 mM, respectively. In A. halophytica, for each CO2 molecule photoassimilated two sulfide molecules are oxidized to elemental sulfur, which is excreted from the cells.The ecological and evolutionary significance of anoxygenic photosynthesis in the cyanobacteria is discussed. PMID:402355

  15. Occurrence of facultative anoxygenic photosynthesis among filamentous and unicellular cyanobacteria.

    PubMed

    Garlick, S; Oren, A; Padan, E

    1977-02-01

    Eleven of 21 cyanobacteria strains examined are capable of facultative anoxygenic photosynthesis, as shown by their ability to photoassimilate CO2 in the presence of Na2S, 3-(3,4-dichlorophenyl)-1,1-dimethylurea and 703-nm light. These include different cyanobacterial types (filamentous and unicellular) of different growth histories (aerobic, anaerobic, and marine and freshwater). Oscillatoria limnetica, Aphanothece halophytica (7418), and Lyngbya (7104) have different optimal concentrations of Na2S permitting CO2 photoassimilation, above which the rate decreases: 3.5, 0.7, and 0.1 mM, respectively. In A. halophytica, for each CO2 molecule photoassimilated two sulfide molecules are oxidized to elemental sulfur, which is excreted from the cells. The ecological and evolutionary significance of anoxygenic photosynthesis in the cyanobacteria is discussed. PMID:402355

  16. The Genome of Heliobacterium modesticaldum, a Phototrophic Representative of the Firmicutes Containing the Simplest Photosynthetic Apparatus▿ †

    PubMed Central

    Sattley, W. Matthew; Madigan, Michael T.; Swingley, Wesley D.; Cheung, Patricia C.; Clocksin, Kate M.; Conrad, Amber L.; Dejesa, Liza C.; Honchak, Barbara M.; Jung, Deborah O.; Karbach, Lauren E.; Kurdoglu, Ahmet; Lahiri, Surobhi; Mastrian, Stephen D.; Page, Lawrence E.; Taylor, Heather L.; Wang, Zi T.; Raymond, Jason; Chen, Min; Blankenship, Robert E.; Touchman, Jeffrey W.

    2008-01-01

    Despite the fact that heliobacteria are the only phototrophic representatives of the bacterial phylum Firmicutes, genomic analyses of these organisms have yet to be reported. Here we describe the complete sequence and analysis of the genome of Heliobacterium modesticaldum, a thermophilic species belonging to this unique group of phototrophs. The genome is a single 3.1-Mb circular chromosome containing 3,138 open reading frames. As suspected from physiological studies of heliobacteria that have failed to show photoautotrophic growth, genes encoding enzymes for known autotrophic pathways in other phototrophic organisms, including ribulose bisphosphate carboxylase (Calvin cycle), citrate lyase (reverse citric acid cycle), and malyl coenzyme A lyase (3-hydroxypropionate pathway), are not present in the H. modesticaldum genome. Thus, heliobacteria appear to be the only known anaerobic anoxygenic phototrophs that are not capable of autotrophy. Although for some cellular activities, such as nitrogen fixation, there is a full complement of genes in H. modesticaldum, other processes, including carbon metabolism and endosporulation, are more genetically streamlined than they are in most other low-G+C gram-positive bacteria. Moreover, several genes encoding photosynthetic functions in phototrophic purple bacteria are not present in the heliobacteria. In contrast to the nutritional flexibility of many anoxygenic phototrophs, the complete genome sequence of H. modesticaldum reveals an organism with a notable degree of metabolic specialization and genomic reduction. PMID:18441057

  17. Anoxygenic Photosynthesis Controls Oxygenic Photosynthesis in a Cyanobacterium from a Sulfidic Spring

    PubMed Central

    Al-Najjar, Mohammad A. A.; Yilmaz, Pelin; Lavik, Gaute; de Beer, Dirk; Polerecky, Lubos

    2015-01-01

    Before the Earth's complete oxygenation (0.58 to 0.55 billion years [Ga] ago), the photic zone of the Proterozoic oceans was probably redox stratified, with a slightly aerobic, nutrient-limited upper layer above a light-limited layer that tended toward euxinia. In such oceans, cyanobacteria capable of both oxygenic and sulfide-driven anoxygenic photosynthesis played a fundamental role in the global carbon, oxygen, and sulfur cycle. We have isolated a cyanobacterium, Pseudanabaena strain FS39, in which this versatility is still conserved, and we show that the transition between the two photosynthetic modes follows a surprisingly simple kinetic regulation controlled by this organism's affinity for H2S. Specifically, oxygenic photosynthesis is performed in addition to anoxygenic photosynthesis only when H2S becomes limiting and its concentration decreases below a threshold that increases predictably with the available ambient light. The carbon-based growth rates during oxygenic and anoxygenic photosynthesis were similar. However, Pseudanabaena FS39 additionally assimilated NO3− during anoxygenic photosynthesis. Thus, the transition between anoxygenic and oxygenic photosynthesis was accompanied by a shift of the C/N ratio of the total bulk biomass. These mechanisms offer new insights into the way in which, despite nutrient limitation in the oxic photic zone in the mid-Proterozoic oceans, versatile cyanobacteria might have promoted oxygenic photosynthesis and total primary productivity, a key step that enabled the complete oxygenation of our planet and the subsequent diversification of life. PMID:25576611

  18. A Combined Molecular and Isotopic Study of Anoxygenic Photosynthesis in Meromictic Lakes of the Northwestern United States

    NASA Astrophysics Data System (ADS)

    Harris, J. H., IV; Gilhooly, W., III; Crane, E. J., III; Steinman, B.; Shelton, M. R.

    2014-12-01

    Sulfur isotope fractionations within the chemocline can be an indication of green and purple sulfur photosynthetic activity. This isotopic signal is, however, small and variable, on the order of +2-6‰ (Zerkle et al. 2009). It is therefore advantageous to investigate the environmental and ecological effects on this signal so that these influences can be taken into account when estimating the contribution of anoxygenic phototrophs to the sulfur cycle in aquatic environments. This project aims to investigate the ways in which anoxygenic phototroph community structure and lake water geochemistry impact the sulfur isotope fractionation expressed during anoxygenic photosynthesis in meromictic lakes. During the summer of 2013, water column profile analysis of six lakes in the Pacific Northwest (located in eastern Washington and western Montana) were conducted to assess photosynthetically available radiation, salinity, pH, temperature, dissolved solids, and specific conductivity. Water column samples were obtained to determine the sulfur isotopic composition of dissolved sulfate and sulfide, major ion and sulfide concentrations. Microbial samples were also collected for genetic sequencing. Initial results found green (e.g., Chlorobiaceae sp.) and purple (e.g., Lamprocystis purpurea) bacteria at the same depth in one of the study lakes. These data, in addition to the same suite of samples collected in the summer of 2014, provide insight into relationships between the isotopic composition of sulfur (in H2S, S0, and SO4), lake water chemistry, and the presence or absence of green and purple sulfur bacteria.

  19. Temporal metatranscriptomic patterning in phototrophic Chloroflexi inhabiting a microbial mat in a geothermal spring.

    PubMed

    Klatt, Christian G; Liu, Zhenfeng; Ludwig, Marcus; Kühl, Michael; Jensen, Sheila I; Bryant, Donald A; Ward, David M

    2013-09-01

    Filamentous anoxygenic phototrophs (FAPs) are abundant members of microbial mat communities inhabiting neutral and alkaline geothermal springs. Natural populations of FAPs related to Chloroflexus spp. and Roseiflexus spp. have been well characterized in Mushroom Spring, where they occur with unicellular cyanobacteria related to Synechococcus spp. strains A and B'. Metatranscriptomic sequencing was applied to the microbial community to determine how FAPs regulate their gene expression in response to fluctuating environmental conditions and resource availability over a diel period. Transcripts for genes involved in the biosynthesis of bacteriochlorophylls (BChls) and photosynthetic reaction centers were much more abundant at night. Both Roseiflexus spp. and Chloroflexus spp. expressed key genes involved in the 3-hydroxypropionate (3-OHP) carbon dioxide fixation bi-cycle during the day, when these FAPs have been thought to perform primarily photoheterotrophic and/or aerobic chemoorganotrophic metabolism. The expression of genes for the synthesis and degradation of storage polymers, including glycogen, polyhydroxyalkanoates and wax esters, suggests that FAPs produce and utilize these compounds at different times during the diel cycle. We summarize these results in a proposed conceptual model for temporal changes in central carbon metabolism and energy production of FAPs living in a natural environment. The model proposes that, at night, Chloroflexus spp. and Roseiflexus spp. synthesize BChl, components of the photosynthetic apparatus, polyhydroxyalkanoates and wax esters in concert with fermentation of glycogen. It further proposes that, in daytime, polyhydroxyalkanoates and wax esters are degraded and used as carbon and electron reserves to support photomixotrophy via the 3-OHP bi-cycle. PMID:23575369

  20. Temporal metatranscriptomic patterning in phototrophic Chloroflexi inhabiting a microbial mat in a geothermal spring

    PubMed Central

    Klatt, Christian G; Liu, Zhenfeng; Ludwig, Marcus; Kühl, Michael; Jensen, Sheila I; Bryant, Donald A; Ward, David M

    2013-01-01

    Filamentous anoxygenic phototrophs (FAPs) are abundant members of microbial mat communities inhabiting neutral and alkaline geothermal springs. Natural populations of FAPs related to Chloroflexus spp. and Roseiflexus spp. have been well characterized in Mushroom Spring, where they occur with unicellular cyanobacteria related to Synechococcus spp. strains A and B′. Metatranscriptomic sequencing was applied to the microbial community to determine how FAPs regulate their gene expression in response to fluctuating environmental conditions and resource availability over a diel period. Transcripts for genes involved in the biosynthesis of bacteriochlorophylls (BChls) and photosynthetic reaction centers were much more abundant at night. Both Roseiflexus spp. and Chloroflexus spp. expressed key genes involved in the 3-hydroxypropionate (3-OHP) carbon dioxide fixation bi-cycle during the day, when these FAPs have been thought to perform primarily photoheterotrophic and/or aerobic chemoorganotrophic metabolism. The expression of genes for the synthesis and degradation of storage polymers, including glycogen, polyhydroxyalkanoates and wax esters, suggests that FAPs produce and utilize these compounds at different times during the diel cycle. We summarize these results in a proposed conceptual model for temporal changes in central carbon metabolism and energy production of FAPs living in a natural environment. The model proposes that, at night, Chloroflexus spp. and Roseiflexus spp. synthesize BChl, components of the photosynthetic apparatus, polyhydroxyalkanoates and wax esters in concert with fermentation of glycogen. It further proposes that, in daytime, polyhydroxyalkanoates and wax esters are degraded and used as carbon and electron reserves to support photomixotrophy via the 3-OHP bi-cycle. PMID:23575369

  1. Community shift from phototrophic to chemotrophic sulfide oxidation following anoxic holomixis in a stratified seawater lake.

    PubMed

    Pjevac, Petra; Korlević, Marino; Berg, Jasmine S; Bura-Nakić, Elvira; Ciglenečki, Irena; Amann, Rudolf; Orlić, Sandi

    2015-01-01

    Most stratified sulfidic holomictic lakes become oxygenated after annual turnover. In contrast, Lake Rogoznica, on the eastern Adriatic coast, has been observed to undergo a period of water column anoxia after water layer mixing and establishment of holomictic conditions. Although Lake Rogoznica's chemistry and hydrography have been studied extensively, it is unclear how the microbial communities typically inhabiting the oxic epilimnion and a sulfidic hypolimnion respond to such a drastic shift in redox conditions. We investigated the impact of anoxic holomixis on microbial diversity and microbially mediated sulfur cycling in Lake Rogoznica with an array of culture-independent microbiological methods. Our data suggest a tight coupling between the lake's chemistry and occurring microorganisms. During stratification, anoxygenic phototrophic sulfur bacteria were dominant at the chemocline and in the hypolimnion. After an anoxic mixing event, the anoxygenic phototrophic sulfur bacteria entirely disappeared, and the homogeneous, anoxic water column was dominated by a bloom of gammaproteobacterial sulfur oxidizers related to the GSO/SUP05 clade. This study is the first report of a community shift from phototrophic to chemotrophic sulfide oxidizers as a response to anoxic holomictic conditions in a seasonally stratified seawater lake. PMID:25344237

  2. Community Shift from Phototrophic to Chemotrophic Sulfide Oxidation following Anoxic Holomixis in a Stratified Seawater Lake

    PubMed Central

    Korlević, Marino; Berg, Jasmine S.; Bura-Nakić, Elvira; Ciglenečki, Irena; Amann, Rudolf; Orlić, Sandi

    2014-01-01

    Most stratified sulfidic holomictic lakes become oxygenated after annual turnover. In contrast, Lake Rogoznica, on the eastern Adriatic coast, has been observed to undergo a period of water column anoxia after water layer mixing and establishment of holomictic conditions. Although Lake Rogoznica's chemistry and hydrography have been studied extensively, it is unclear how the microbial communities typically inhabiting the oxic epilimnion and a sulfidic hypolimnion respond to such a drastic shift in redox conditions. We investigated the impact of anoxic holomixis on microbial diversity and microbially mediated sulfur cycling in Lake Rogoznica with an array of culture-independent microbiological methods. Our data suggest a tight coupling between the lake's chemistry and occurring microorganisms. During stratification, anoxygenic phototrophic sulfur bacteria were dominant at the chemocline and in the hypolimnion. After an anoxic mixing event, the anoxygenic phototrophic sulfur bacteria entirely disappeared, and the homogeneous, anoxic water column was dominated by a bloom of gammaproteobacterial sulfur oxidizers related to the GSO/SUP05 clade. This study is the first report of a community shift from phototrophic to chemotrophic sulfide oxidizers as a response to anoxic holomictic conditions in a seasonally stratified seawater lake. PMID:25344237

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

    NASA Technical Reports Server (NTRS)

    Trueper, H. G.

    1985-01-01

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

  4. Cytochromes and iron sulfur proteins in sulfur metabolism of phototrophic bacteria

    NASA Technical Reports Server (NTRS)

    Fischer, U.

    1985-01-01

    Dissimilatory sulfur metabolism in phototrophic sulfur bacteria provides the bacteria with electrons for photosynthetic electron transport chain and, with energy. Assimilatory sulfate reduction is necessary for the biosynthesis of sulfur-containing cell components. Sulfide, thiosulfate, and elemental sulfur are the sulfur compounds most commonly used by phototrophic bacteria as electron donors for anoxygenic photosynthesis. Cytochromes or other electron transfer proteins, like high-potential-iron-sulfur protein (HIPIP) function as electron acceptors or donors for most enzymatic steps during the oxidation pathways of sulfide or thiosulfate. Yet, heme- or siroheme-containing proteins themselves undergo enzymatic activities in sulfur metabolism. Sirohemes comprise a porphyrin-like prosthetic group of sulfate reductase. eenzymatic reactions involve electron transfer. Electron donors or acceptors are necessary for each reaction. Cytochromes and iron sulfur problems, are able to transfer electrons.

  5. Sulfur cycling and metabolism of phototrophic and filamentous sulfur bacteria

    NASA Technical Reports Server (NTRS)

    Guerrero, R.; Brune, D.; Poplawski, R.; Schmidt, T. M.

    1985-01-01

    Phototrophic sulfur bacteria taken from different habitate (Alum Rock State Park, Palo Alto salt marsh, and Big Soda Lake) were grown on selective media, characterized by morphological and pigment analysis, and compared with bacteria maintained in pure culture. A study was made of the anaerobic reduction of intracellular sulfur globules by a phototrophic sulfur bacterium (Chromatium vinosum) and a filamentous aerobic sulfur bacterium (Beggiatoa alba). Buoyant densities of different bacteria were measured in Percoll gradients. This method was also used to separate different chlorobia in mixed cultures and to assess the relative homogeneity of cultures taken directly or enriched from natural samples (including the purple bacterial layer found at a depth of 20 meters at Big Soda Lake.) Interactions between sulfide oxidizing bacteria were studied.

  6. Phototrophic utilization of toluene under anoxic conditions by a new strain of blastochloris sulfoviridis

    PubMed

    Zengler; Heider; Rossello-Mora; Widdel

    1999-10-01

    The capacity of anoxygenic phototrophic bacteria to utilize aromatic hydrocarbons was investigated in enrichment cultures with toluene. When mineral medium with toluene (provided in an inert carrier phase) was inoculated with activated sludge and incubated under infrared illumination (> 750 nm), a red-to-brownish culture developed. Agar dilution series indicated the dominance of two types of phototrophic bacteria. One type formed red colonies, had rod-shaped cells with budding division, and grew on benzoate but not on toluene. The other type formed yellow-to-brown colonies, had oval cells, and utilized toluene and benzoate. One strain of the latter type, ToP1, was studied in detail. Sequence analysis of the 16S rRNA gene and DNA-DNA hybridization indicated an affiliation of strain ToP1 with the species Blastochloris sulfoviridis, a member of the alpha-subclass of Proteobacteria. However, the type strain (DSM 729) of Blc. sulfoviridis grew neither on toluene nor on benzoate. Light-dependent consumption of toluene in the presence of carbon dioxide and formation of cell mass by strain ToP1 were demonstrated in quantitative growth experiments. Strain ToP1 is the first phototrophic bacterium shown to utilize an aromatic hydrocarbon. In the supernatant of toluene-grown cultures and in cell-free extracts incubated with toluene and fumarate, the formation of benzylsuccinate was detected. These findings indicate that the phototrophic bacterium activates toluene anaerobically by the same mechanism that has been reported for denitrifying and sulfate-reducing bacteria. The natural abundance of phototrophic bacteria with the capacity for toluene utilization was examined in freshwater habitats. Counting series revealed that up to around 1% (1.8 x 10(5) cells per gram dry mass of sample) of the photoheterotrophic population cultivable with acetate grew on toluene. PMID:10525736

  7. Biogeography of thermophilic phototrophic bacteria belonging to Roseiflexus genus.

    PubMed

    Gaisin, Vasil A; Grouzdev, Denis S; Namsaraev, Zorigto B; Sukhacheva, Marina V; Gorlenko, Vladimir M; Kuznetsov, Boris B

    2016-03-01

    Isolated environments such as hot springs are particularly interesting for studying the microbial biogeography. These environments create an 'island effect' leading to genetic divergence. We studied the phylogeographic pattern of thermophilic anoxygenic phototrophic bacteria, belonging to the Roseiflexus genus. The main characteristic of the observed pattern was geographic and geochronologic fidelity to the hot springs within Circum-Pacific and Alpine-Himalayan-Indonesian orogenic belts. Mantel test revealed a correlation between genetic divergence and geographic distance among the phylotypes. Cluster analysis revealed a regional differentiation of the global phylogenetic pattern. The phylogeographic pattern is in correlation with geochronologic events during the break up of Pangaea that led to the modern configuration of continents. To our knowledge this is the first geochronological scenario of intercontinental prokaryotic taxon divergence. The existence of the modern phylogeographic pattern contradicts with the existence of the ancient evolutionary history of the Roseiflexus group proposed on the basis of its deep-branching phylogenetic position. These facts indicate that evolutionary rates in Roseiflexus varied over a wide range. PMID:26826142

  8. Arsenic(III) fuels anoxygenic photosynthesis in hot spring biofilms from Mono Lake, California

    USGS Publications Warehouse

    Kulp, T.R.; Hoeft, S.E.; Asao, M.; Madigan, M.T.; Hollibaugh, J.T.; Fisher, J.C.; Stolz, J.F.; Culbertson, C.W.; Miller, L.G.; Oremland, R.S.

    2008-01-01

    Phylogenetic analysis indicates that microbial arsenic metabolism is ancient and probably extends back to the primordial Earth. In microbial biofilms growing on the rock surfaces of anoxic brine pools fed by hot springs containing arsenite and sulfide at high concentrations, we discovered light-dependent oxidation of arsenite [As(III)] to arsenate [As(V)] occurring under anoxic conditions. The communities were composed primarily of Ectothiorhodospira-like purple bacteria or Oscillatoria-like cyanobacteria. A pure culture of a photosynthetic bacterium grew as a photoautotroph when As(III) was used as the sole photosynthetic electron donor. The strain contained genes encoding a putative As(V) reductase but no detectable homologs of the As(III) oxidase genes of aerobic chemolithotrophs, suggesting a reverse functionality for the reductase. Production of As(V) by anoxygenic photosynthesis probably opened niches for primordial Earth's first As(V)-respiring prokaryotes.

  9. Abundance, depth distribution, and composition of aerobic bacteriochlorophyll a-producing bacteria in four basins of the central Baltic Sea.

    PubMed

    Salka, Ivette; Moulisová, Vladimíra; Koblízek, Michal; Jost, Günter; Jürgens, Klaus; Labrenz, Matthias

    2008-07-01

    The abundance, vertical distribution, and diversity of aerobic anoxygenic phototrophic bacteria (AAP) were studied at four basins of the Baltic Sea. AAP were enumerated by infrared epifluorescence microscopy, and their diversity was analyzed by using pufM gene clone libraries. In addition, numbers of CFU containing the pufM gene were determined, and representative strains were isolated. Both approaches indicated that AAP reached maximal abundance in the euphotic zone. Maximal AAP abundance was 2.5 x 10(5) cells ml(-1) (11% of total prokaryotes) or 1.0 x 10(3) CFU ml(-1) (9 to 10% of total CFU). Environmental pufM clone sequences were grouped into 11 operational taxonomic units phylogenetically related to cultivated members of the Alpha-, Beta-, and Gammaproteobacteria. In spite of varying pufM compositions, five clones were present in all libraries. Of these, Jannaschia-related clones were always found in relative abundances representing 25 to 30% of the total AAP clones. The abundances of the other clones varied. Clones potentially affiliated with typical freshwater Betaproteobacteria sequences were present at three Baltic Sea stations, whereas clones grouping with Loktanella represented 40% of the total cell numbers in the Gotland Basin. For three alphaproteobacterial clones, probable pufM phylogenetic relationships were supported by 16S rRNA gene analyses of Baltic AAP isolates, which showed nearly identical pufM sequences. Our data indicate that the studied AAP assemblages represented a mixture of marine and freshwater taxa, thus characterizing the Baltic Sea as a "melting pot" of abundant, polyphyletic aerobic photoheterotrophic bacteria. PMID:18502937

  10. A proposed aerobic granules size development scheme for aerobic granulation process.

    PubMed

    Dahalan, Farrah Aini; Abdullah, Norhayati; Yuzir, Ali; Olsson, Gustaf; Salmiati; Hamdzah, Myzairah; Din, Mohd Fadhil Mohd; Ahmad, Siti Aqlima; Khalil, Khalilah Abdul; Anuar, Aznah Nor; Noor, Zainura Zainon; Ujang, Zaini

    2015-04-01

    Aerobic granulation is increasingly used in wastewater treatment due to its unique physical properties and microbial functionalities. Granule size defines the physical properties of granules based on biomass accumulation. This study aims to determine the profile of size development under two physicochemical conditions. Two identical bioreactors namely Rnp and Rp were operated under non-phototrophic and phototrophic conditions, respectively. An illustrative scheme was developed to comprehend the mechanism of size development that delineates the granular size throughout the granulation. Observations on granules' size variation have shown that activated sludge revolutionised into the form of aerobic granules through the increase of biomass concentration in bioreactors which also determined the changes of granule size. Both reactors demonstrated that size transformed in a similar trend when tested with and without illumination. Thus, different types of aerobic granules may increase in size in the same way as recommended in the aerobic granule size development scheme. PMID:25661308

  11. Engineering and Coordination of Regulatory Networks and Intracellular Complexes to Maximize Hydrogen Production by Phototrophic Microorganisms

    SciTech Connect

    James C. Liao

    2012-05-22

    This project is a collaboration with F. R. Tabita of Ohio State. Our major goal is to understand the factors and regulatory mechanisms that influence hydrogen production. The organisms to be utilized in this study, phototrophic microorganisms, in particular nonsulfur purple (NSP) bacteria, catalyze many significant processes including the assimilation of carbon dioxide into organic carbon, nitrogen fixation, sulfur oxidation, aromatic acid degradation, and hydrogen oxidation/evolution. Our part of the project was to develop a modeling technique to investigate the metabolic network in connection to hydrogen production and regulation. Organisms must balance the pathways that generate and consume reducing power in order to maintain redox homeostasis to achieve growth. Maintaining this homeostasis in the nonsulfur purple photosynthetic bacteria is a complex feat with many avenues that can lead to balance, as these organisms possess versatile metabolic capabilities including anoxygenic photosynthesis, aerobic or anaerobic respiration, and fermentation. Growth is achieved by using H{sub 2} as an electron donor and CO{sub 2} as a carbon source during photoautotrophic and chemoautotrophic growth, where CO{sub 2} is fixed via the Calvin-Benson-Bassham (CBB) cycle. Photoheterotrophic growth can also occur when alternative organic carbon compounds are utilized as both the carbon source and electron donor. Regardless of the growth mode, excess reducing equivalents generated as a result of oxidative processes, must be transferred to terminal electron acceptors, thus insuring that redox homeostasis is maintained in the cell. Possible terminal acceptors include O{sub 2}, CO{sub 2}, organic carbon, or various oxyanions. Cells possess regulatory mechanisms to balance the activity of the pathways which supply energy, such as photosynthesis, and those that consume energy, such as CO{sub 2} assimilation or N{sub 2} fixation. The major route for CO{sub 2} assimilation is the CBB

  12. Abundance, Depth Distribution, and Composition of Aerobic Bacteriochlorophyll a-Producing Bacteria in Four Basins of the Central Baltic Sea▿ †

    PubMed Central

    Salka, Ivette; Moulisová, Vladimíra; Koblížek, Michal; Jost, Günter; Jürgens, Klaus; Labrenz, Matthias

    2008-01-01

    The abundance, vertical distribution, and diversity of aerobic anoxygenic phototrophic bacteria (AAP) were studied at four basins of the Baltic Sea. AAP were enumerated by infrared epifluorescence microscopy, and their diversity was analyzed by using pufM gene clone libraries. In addition, numbers of CFU containing the pufM gene were determined, and representative strains were isolated. Both approaches indicated that AAP reached maximal abundance in the euphotic zone. Maximal AAP abundance was 2.5 × 105 cells ml−1 (11% of total prokaryotes) or 1.0 × 103 CFU ml−1 (9 to 10% of total CFU). Environmental pufM clone sequences were grouped into 11 operational taxonomic units phylogenetically related to cultivated members of the Alpha-, Beta-, and Gammaproteobacteria. In spite of varying pufM compositions, five clones were present in all libraries. Of these, Jannaschia-related clones were always found in relative abundances representing 25 to 30% of the total AAP clones. The abundances of the other clones varied. Clones potentially affiliated with typical freshwater Betaproteobacteria sequences were present at three Baltic Sea stations, whereas clones grouping with Loktanella represented 40% of the total cell numbers in the Gotland Basin. For three alphaproteobacterial clones, probable pufM phylogenetic relationships were supported by 16S rRNA gene analyses of Baltic AAP isolates, which showed nearly identical pufM sequences. Our data indicate that the studied AAP assemblages represented a mixture of marine and freshwater taxa, thus characterizing the Baltic Sea as a “melting pot” of abundant, polyphyletic aerobic photoheterotrophic bacteria. PMID:18502937

  13. Microscale sulfur cycling in the phototrophic pink berry consortia of the Sippewissett Salt Marsh

    PubMed Central

    Wilbanks, Elizabeth G; Jaekel, Ulrike; Salman, Verena; Humphrey, Parris T; Eisen, Jonathan A; Facciotti, Marc T; Buckley, Daniel H; Zinder, Stephen H; Druschel, Gregory K; Fike, David A; Orphan, Victoria J

    2014-01-01

    Microbial metabolism is the engine that drives global biogeochemical cycles, yet many key transformations are carried out by microbial consortia over short spatiotemporal scales that elude detection by traditional analytical approaches. We investigate syntrophic sulfur cycling in the ‘pink berry’ consortia of the Sippewissett Salt Marsh through an integrative study at the microbial scale. The pink berries are macroscopic, photosynthetic microbial aggregates composed primarily of two closely associated species: sulfide-oxidizing purple sulfur bacteria (PB-PSB1) and sulfate-reducing bacteria (PB-SRB1). Using metagenomic sequencing and 34S-enriched sulfate stable isotope probing coupled with nanoSIMS, we demonstrate interspecies transfer of reduced sulfur metabolites from PB-SRB1 to PB-PSB1. The pink berries catalyse net sulfide oxidation and maintain internal sulfide concentrations of 0–500 μm. Sulfide within the berries, captured on silver wires and analysed using secondary ion mass spectrometer, increased in abundance towards the berry interior, while δ34S-sulfide decreased from 6‰ to −31‰ from the exterior to interior of the berry. These values correspond to sulfate–sulfide isotopic fractionations (15–53‰) consistent with either sulfate reduction or a mixture of reductive and oxidative metabolisms. Together this combined metagenomic and high-resolution isotopic analysis demonstrates active sulfur cycling at the microscale within well-structured macroscopic consortia consisting of sulfide-oxidizing anoxygenic phototrophs and sulfate-reducing bacteria. PMID:24428801

  14. Light-Harvesting Antenna System from the Phototrophic Bacterium Roseiflexus castenholzii

    SciTech Connect

    Collins, Aaron M.; Qian, Pu; Tang, Qun; Bocian, David F; Hunter, C. Neil; Blankenship, Robert E.

    2010-08-12

    Photosynthetic organisms have evolved diverse light-harvesting complexes to harness light of various qualities and intensities. Photosynthetic bacteria can have (bacterio)chlorophyll Qy antenna absorption bands ranging from ~650 to ~1100 nm. This broad range of wavelengths has allowed many organisms to thrive in unique light environments. Roseiflexus castenholzii is a niche-adapted, filamentous anoxygenic phototroph (FAP) that lacks chlorosomes, the dominant antenna found in most green bacteria, and here we describe the purification of a full complement of photosynthetic complexes: the light-harvesting (LH) antenna, reaction center (RC), and core complex (RC-LH). By high-performance liquid chromatography separation of bacteriochlorophyll and bacteriopheophytin pigments extracted from the core complex and the RC, the number of subunits that comprise the antenna was determined to be 15 ± 1. Resonance Raman spectroscopy of the carbonyl stretching region displayed modes indicating that 3C-acetyl groups of BChl a are all involved in molecular interactions probably similar to those found in LH1 complexes from purple photosynthetic bacteria. Finally, two-dimensional projections of negatively stained core complexes and the LH antenna revealed a closed, slightly elliptical LH ring with an average diameter of 130 ± 10 Å surrounding a single RC that lacks an H-subunit but is associated with a tetraheme c-type cytochrome.

  15. Anoxygenic photosynthesis modulated Proterozoic oxygen and sustained Earth's middle age

    PubMed Central

    Johnston, D. T.; Wolfe-Simon, F.; Pearson, A.; Knoll, A. H.

    2009-01-01

    Molecular oxygen (O2) began to accumulate in the atmosphere and surface ocean ca. 2,400 million years ago (Ma), but the persistent oxygenation of water masses throughout the oceans developed much later, perhaps beginning as recently as 580–550 Ma. For much of the intervening interval, moderately oxic surface waters lay above an oxygen minimum zone (OMZ) that tended toward euxinia (anoxic and sulfidic). Here we illustrate how contributions to primary production by anoxygenic photoautotrophs (including physiologically versatile cyanobacteria) influenced biogeochemical cycling during Earth's middle age, helping to perpetuate our planet's intermediate redox state by tempering O2 production. Specifically, the ability to generate organic matter (OM) using sulfide as an electron donor enabled a positive biogeochemical feedback that sustained euxinia in the OMZ. On a geologic time scale, pyrite precipitation and burial governed a second feedback that moderated sulfide availability and water column oxygenation. Thus, we argue that the proportional contribution of anoxygenic photosynthesis to overall primary production would have influenced oceanic redox and the Proterozoic O2 budget. Later Neoproterozoic collapse of widespread euxinia and a concomitant return to ferruginous (anoxic and Fe2+ rich) subsurface waters set in motion Earth's transition from its prokaryote-dominated middle age, removing a physiological barrier to eukaryotic diversification (sulfide) and establishing, for the first time in Earth's history, complete dominance of oxygenic photosynthesis in the oceans. This paved the way for the further oxygenation of the oceans and atmosphere and, ultimately, the evolution of complex multicellular organisms. PMID:19805080

  16. Anoxygenic growth of cyanobacteria on Fe(II) and their associated biosignatures: Implications for biotic contributions to Precambrian Banded Iron Formations

    NASA Astrophysics Data System (ADS)

    Parenteau, M.; Jahnke, L. L.; Cady, S. L.; Pierson, B.

    2011-12-01

    Banded Iron Formations (BIFs) are widespread Precambrian sedimentary deposits that accumulated in deep ocean basins or shallow platformal areas with inputs of reduced iron (Fe(II)) and silica from deep ocean hydrothermal activity. There is debate as to whether abiotic or biotic mechanisms were responsible for the oxidation of aqueous Fe(II) and the subsequent accumulation of ferric iron (Fe(III)) mineral assemblages in BIFs. Biotic Fe(II) oxidation could have occurred indirectly as a result of the photosynthetic production of oxygen by cyanobacteria, or could have been directly mediated by anoxygenic phototrophs or chemolithotrophs. The anoxygenic use of Fe(II) as an electron donor for photosynthesis has also been hypothesized in cyanobacteria, representing another biotic mechanism by which Fe(II) could be oxidized in BIFs. This type of photoferrotrophic metabolism may also represent a key step in the evolution of oxygenic photosynthesis. Members of our group have speculated that an intermediate reductant such as Fe(II) could have acted as a transitional electron donor before water. The widespread abundance of Fe(II) in Archean and Neoproterozoic ferruginous oceans would have made it particularly suitable as an electron donor for photosynthesis. We have been searching for modern descendants of such an ancestral "missing link" cyanobacterium in the phototrophic mats at Chocolate Pots, a hot spring in Yellowstone National Park with a constant outflow of anoxic Fe(II)-rich thermal water. Our physiological ecology study of the Synechococcus-Chloroflexi mat using C-14 bicarbonate uptake and autoradiography experiments revealed that the cyanobacteria grow anoxygenically using Fe(II) as an electron donor for photosynthesis in situ. An initial set of similar experiments substituting C-13 bicarbonate as the tracer was used to characterize labeling of the community lipid biomarker signature and confirm the C-14 results. Under light conditions with and without Fe(II), the C

  17. Anthocyanin-dependent anoxygenic photosynthesis in coloured flower petals?

    NASA Astrophysics Data System (ADS)

    Lysenko, Vladimir; Varduny, Tatyana

    2013-11-01

    Chlorophylless flower petals are known to be composed of non-photosynthetic tissues. Here, we show that the light energy storage that can be photoacoustically measured in flower petals of Petunia hybrida is approximately 10-12%. We found that the supposed chlorophylless photosynthesis is an anoxygenic, anthocyanin-dependent process occurring in blue flower petals (ADAPFP), accompanied by non-respiratory light-dependent oxygen uptake and a 1.5-fold photoinduced increase in ATP levels. Using a simple, adhesive tape stripping technique, we have obtained a backside image of an intact flower petal epidermis, revealing sword-shaped ingrowths connecting the cell wall and vacuole, which is of interest for the further study of possible vacuole-related photosynthesis. Approaches to the interpretations of ADAPFP are discussed, and we conclude that these results are not impossible in terms of the known photochemistry of anthocyanins.

  18. Spectral light measurements in microbenthic phototrophic communities with a fiber-optic microprobe coupled to a sensitive diode array detector

    SciTech Connect

    Kuehl, M. ); Joergensen, B.B. )

    1992-12-01

    A diode array detector system for microscale light measurements with fiber-optic microprobes was developed; it measures intensities of 400-900-nm light over >6 orders of magnitude with a spectral resolution of 2-5 nm. Fiber-optic microprobes to measure field radiance or scalar irradiance were coupled to the detector system and used for spectral light measurements in hypersaline microbial mats and in laminated phototrophic communities of coastal sediments. The vertical distribution of major photopigments of microalgae, cyanobacteria, and anoxygenic phototrophic bacteria could be identified from extinction maxima in measured radiance spectra at 430-550 nm (Chl a and carotenoids), 620-625 nm (phycocyanin), 675 nm (Chl a), 745-750 nm (BChl c), 800-810 nm, and 860-880 nm (BChl a). Scalar irradiance spectra exhibited a different spectral composition and a higher light intensity at the sediment surface as compared to incident light. IR light thus reached 200% of incident at the sediment surface. Maximal light penetration was found for IR light, whereas visible light was strongly attenuated in the upper 0-2 mm of the sediment. Measurements of photon scalar irradiance (400-700 nm) were combined with microelectrode measurements of oxygenic photosynthesis in the coastal sediment. With an incident light intensity of 200 [mu]Einst m[sup [minus]2]s[sup [minus]1], photon scalar irradiance reached a maximum of 283 [mu]Einst m[sup [minus]2]s[sup [minus]1] at the sediment surface. The lower boundary of the euphotic zone was 2.2 mm below the surface at a light intensity of 12 [mu]Einst m[sup [minus]2]s[sup [minus]1]. 20 refs., 6 figs.

  19. Development of a real-time PCR method for the detection of fossil 16S rDNA fragments of phototrophic sulfur bacteria in the sediments of Lake Cadagno.

    PubMed

    Ravasi, D F; Peduzzi, S; Guidi, V; Peduzzi, R; Wirth, S B; Gilli, A; Tonolla, M

    2012-05-01

    Lake Cadagno is a crenogenic meromictic lake situated in the southern range of the Swiss Alps characterized by a compact chemocline that has been the object of many ecological studies. The population dynamics of phototrophic sulfur bacteria in the chemocline has been monitored since 1994 with molecular methods such as 16S rRNA gene clone library analysis. To reconstruct paleo-microbial community dynamics, we developed a quantitative real-time PCR methodology for specific detection of 16S rRNA gene sequences of purple and green sulfur bacteria populations from sediment samples. We detected fossil 16S rDNA of nine populations of phototrophic sulfur bacteria down to 9-m sediment depth, corresponding to about 9500 years of the lake's biogeological history. These results provide the first evidence for the presence of 16S rDNA of anoxygenic phototrophic bacteria in Holocene sediments of an alpine meromictic lake and indicate that the water column stratification and the bacterial plume were already present in Lake Cadagno thousands of years ago. The finding of Chlorobium clathratiforme remains in all the samples analyzed shows that this population, identified in the water column only in 2001, was already a part of the lake's biota in the past. PMID:22433067

  20. Insights into chemotaxonomic composition and carbon cycling of phototrophic communities in an artesian sulfur-rich spring (Zodletone, Oklahoma, USA), a possible analog for ancient microbial mat systems.

    PubMed

    Bühring, S I; Sievert, S M; Jonkers, H M; Ertefai, T; Elshahed, M S; Krumholz, L R; Hinrichs, K-U

    2011-03-01

    Zodletone spring in Oklahoma is a unique environment with high concentrations of dissolved-sulfide (10 mm) and short-chain gaseous alkanes, exhibiting characteristics that are reminiscent of conditions that are thought to have existed in Earth's history, in particular the late Archean and early-to-mid Proterozoic. Here, we present a process-oriented investigation of the microbial community in two distinct mat formations at the spring source, (1) the top of the sediment in the source pool and (2) the purple streamers attached to the side walls. We applied a combination of pigment and lipid biomarker analyses, while functional activities were investigated in terms of oxygen production (microsensor analysis) and carbon utilization ((13)C incorporation experiments). Pigment analysis showed cyanobacterial pigments, in addition to pigments from purple sulfur bacteria (PSB), green sulfur bacteria (GSB) and Chloroflexus-like bacteria (CLB). Analysis of intact polar lipids (IPLs) in the source sediment confirmed the presence of phototrophic organisms via diacylglycerol phospholipids and betaine lipids, whereas glyceroldialkylglyceroltetraether additionally indicated the presence of archaea. No archaeal IPLs were found in the purple streamers, which were strongly dominated by betaine lipids. (13)C-bicarbonate- and -acetate-labeling experiments indicated cyanobacteria as predominant phototrophs in the source sediment, carbon was actively fixed by PSB/CLB/GSB in purple streamers by using near infrared light. Despite the presence of cyanobacteria, no oxygen could be detected in the presence of light, suggesting anoxygenic photosynthesis as the major metabolic process at this site. Our investigations furthermore indicated photoheterotrophy as an important process in both habitats. We obtained insights into a syntrophically operating phototrophic community in an ecosystem that bears resemblance to early Earth conditions, where cyanobacteria constitute an important contributor to

  1. Phototrophic sulfide oxidation: environmental insights and a method for kinetic analysis

    PubMed Central

    Hanson, Thomas E.; Luther, George W.; Findlay, Alyssa J.; MacDonald, Daniel J.; Hess, Daniel

    2013-01-01

    Previously, we presented data that indicated microbial sulfide oxidation would out-compete strictly chemical, abiotic sulfide oxidation reactions under nearly all conditions relevant to extant ecosystems (Luther et al., 2011). In particular, we showed how anaerobic microbial sulfide oxidation rates were several orders of magnitude higher than even metal catalyzed aerobic sulfide oxidation processes. The fact that biotic anaerobic sulfide oxidation is kinetically superior to abiotic reactions implies that nearly all anaerobic and sulfidic environments should host microbial populations that oxidize sulfide at appreciable rates. This was likely an important biogeochemical process during long stretches of euxinia in the oceans suggested by the geologic record. In particular, phototrophic sulfide oxidation allows the utilization of carbon dioxide as the electron acceptor suggesting that this process should be particularly widespread rather than relying on the presence of other chemical oxidants. Using the Chesapeake Bay as an example, we argue that phototrophic sulfide oxidation may be more important in many environments than is currently appreciated. Finally, we present methodological considerations to assist other groups that wish to study this process. PMID:24391629

  2. Deep-water anoxygenic photosythesis in a ferruginous chemocline.

    PubMed

    Crowe, S A; Maresca, J A; Jones, C; Sturm, A; Henny, C; Fowle, D A; Cox, R P; Delong, E F; Canfield, D E

    2014-07-01

    Ferruginous Lake Matano, Indonesia hosts one of the deepest anoxygenic photosynthetic communities on Earth. This community is dominated by low-light adapted, BChl e-synthesizing green sulfur bacteria (GSB), which comprise ~25% of the microbial community immediately below the oxic-anoxic boundary (OAB; 115-120 m in 2010). The size of this community is dependent on the mixing regime within the lake and the depth of the OAB-at ~117 m, the GSB live near their low-light limit. Slow growth and C-fixation rates suggest that the Lake Matano GSB can be supported by sulfide even though it only accumulates to scarcely detectable (low μm to nm) concentrations. A model laboratory strain (Chlorobaculum tepidum) is indeed able to access HS- for oxidation at nm concentrations. Furthermore, the GSB in Lake Matano possess a full complement of S-oxidizing genes. Together, this physiological and genetic information suggests that deep-water GSB can be supported by a S-cycle, even under ferruginous conditions. The constraints we place on the metabolic capacity and physiology of GSB have important geobiological implications. Biomarkers diagnostic of GSB would be a good proxy for anoxic conditions but could not discriminate between euxinic and ferruginous states, and though GSB biomarkers could indicate a substantial GSB community, such a community may exist with very little metabolic activity. The light requirements of GSB indicate that at light levels comparable to those in the OAB of Lake Matano or the Black Sea, GSB would have contributed little to global ocean primary production, nutrient cycling, and banded iron formation (BIF) deposition in the Precambrian. Before the proliferation of oxygenic photosynthesis, shallower OABs and lower light absorption in the ocean's surface waters would have permitted greater light availability to GSB, potentially leading to a greater role for GSB in global biogeochemical cycles. PMID:24923179

  3. Coexistence of Microaerophilic, Nitrate-Reducing, and Phototrophic Fe(II) Oxidizers and Fe(III) Reducers in Coastal Marine Sediment

    PubMed Central

    Laufer, Katja; Nordhoff, Mark; Røy, Hans; Schmidt, Caroline; Behrens, Sebastian; Jørgensen, Bo Barker

    2015-01-01

    Iron is abundant in sediments, where it can be biogeochemically cycled between its divalent and trivalent redox states. The neutrophilic microbiological Fe cycle involves Fe(III)-reducing and three different physiological groups of Fe(II)-oxidizing microorganisms, i.e., microaerophilic, anoxygenic phototrophic, and nitrate-reducing Fe(II) oxidizers. However, it is unknown whether all three groups coexist in one habitat and how they are spatially distributed in relation to gradients of O2, light, nitrate, and Fe(II). We examined two coastal marine sediments in Aarhus Bay, Denmark, by cultivation and most probable number (MPN) studies for Fe(II) oxidizers and Fe(III) reducers and by quantitative-PCR (qPCR) assays for microaerophilic Fe(II) oxidizers. Our results demonstrate the coexistence of all three metabolic types of Fe(II) oxidizers and Fe(III) reducers. In qPCR, microaerophilic Fe(II) oxidizers (Zetaproteobacteria) were present with up to 3.2 × 106 cells g dry sediment−1. In MPNs, nitrate-reducing Fe(II) oxidizers, anoxygenic phototrophic Fe(II) oxidizers, and Fe(III) reducers reached cell numbers of up to 3.5 × 104, 3.1 × 102, and 4.4 × 104 g dry sediment−1, respectively. O2 and light penetrated only a few millimeters, but the depth distribution of the different iron metabolizers did not correlate with the profile of O2, Fe(II), or light. Instead, abundances were homogeneous within the upper 3 cm of the sediment, probably due to wave-induced sediment reworking and bioturbation. In microaerophilic Fe(II)-oxidizing enrichment cultures, strains belonging to the Zetaproteobacteria were identified. Photoferrotrophic enrichments contained strains related to Chlorobium and Rhodobacter; the nitrate-reducing Fe(II) enrichments contained strains related to Hoeflea and Denitromonas. This study shows the coexistence of all three types of Fe(II) oxidizers in two near-shore marine environments and the potential for competition and interrelationships between them

  4. Coexistence of Microaerophilic, Nitrate-Reducing, and Phototrophic Fe(II) Oxidizers and Fe(III) Reducers in Coastal Marine Sediment.

    PubMed

    Laufer, Katja; Nordhoff, Mark; Røy, Hans; Schmidt, Caroline; Behrens, Sebastian; Jørgensen, Bo Barker; Kappler, Andreas

    2015-01-01

    Iron is abundant in sediments, where it can be biogeochemically cycled between its divalent and trivalent redox states. The neutrophilic microbiological Fe cycle involves Fe(III)-reducing and three different physiological groups of Fe(II)-oxidizing microorganisms, i.e., microaerophilic, anoxygenic phototrophic, and nitrate-reducing Fe(II) oxidizers. However, it is unknown whether all three groups coexist in one habitat and how they are spatially distributed in relation to gradients of O2, light, nitrate, and Fe(II). We examined two coastal marine sediments in Aarhus Bay, Denmark, by cultivation and most probable number (MPN) studies for Fe(II) oxidizers and Fe(III) reducers and by quantitative-PCR (qPCR) assays for microaerophilic Fe(II) oxidizers. Our results demonstrate the coexistence of all three metabolic types of Fe(II) oxidizers and Fe(III) reducers. In qPCR, microaerophilic Fe(II) oxidizers (Zetaproteobacteria) were present with up to 3.2 × 10(6) cells g dry sediment(-1). In MPNs, nitrate-reducing Fe(II) oxidizers, anoxygenic phototrophic Fe(II) oxidizers, and Fe(III) reducers reached cell numbers of up to 3.5 × 10(4), 3.1 × 10(2), and 4.4 × 10(4) g dry sediment(-1), respectively. O2 and light penetrated only a few millimeters, but the depth distribution of the different iron metabolizers did not correlate with the profile of O2, Fe(II), or light. Instead, abundances were homogeneous within the upper 3 cm of the sediment, probably due to wave-induced sediment reworking and bioturbation. In microaerophilic Fe(II)-oxidizing enrichment cultures, strains belonging to the Zetaproteobacteria were identified. Photoferrotrophic enrichments contained strains related to Chlorobium and Rhodobacter; the nitrate-reducing Fe(II) enrichments contained strains related to Hoeflea and Denitromonas. This study shows the coexistence of all three types of Fe(II) oxidizers in two near-shore marine environments and the potential for competition and interrelationships between

  5. Iron, Sulfur, Arsenic and Water: Geochemical Implications of Facultative Anoxygenic Photosynthesis in Cyanobacteria and the Slow Rise of Oxygen

    NASA Astrophysics Data System (ADS)

    Wolfe-Simon, F.; Johnston, D. T.; Girguis, P. R.; Pearson, A.; Knoll, A. H.

    2008-12-01

    Over geologic time, the global rise in atmospheric oxygen (O2) is attributed to the evolution and wide spread proliferation of oxygenic photosynthesis in cyanobacteria. However, cyanobacteria maintain a metabolic flexibility that may not always result in O2 release. Specifically, cyanobacteria can use a variety of alternative electron donors, rather than water, that are also readily oxidized. These may include sulfur, iron, and arsenic. Cyanobacteria are thus not uniquely constrained towards O2 production. Changes in the bioavailability of these key elements may have had dramatic consequences for and resulted in the slow accumulation of O2 in the atmosphere. In particular, by using facultative anoxygenic photosynthesis the cells maintain advantageous anaerobic conditions for N2-fixation. Although other types of bacteria are capable of N2-fixation, cyanobacteria singularly possess the dynamic capability of generating and surviving O2. These two processes "pull" the cells in opposite directions, metabolically speaking, around an aerobic-anaerobic continuum. Such a strategy also confers a distinct competitive advantage for cyanobacteria over photosynthetic eukaryotes, as they can endure widespread euxinia and maintain their cellular N quota. In an anoxic and/or sulfidic ocean, cyanobacteria would be expected to dominate over eukaryotic algae. Here we present Bayesian constructed phylogenetic distribution of specific genes and the metabolic role of key enzymes that form the basis of this hypothesis. We further suggest that the consequences of this proposed ecosystem structure altered the redox balance of the fluid Earth (atmosphere and oceans) and can help explain the observed long-term geochemical stasis and slow rates of eukaryotic diversification. We suggest that the underlying control for global oxygenation was a synergistic interplay between the evolution and elastic physiology of cyanobacteria as they impacted the redox state of early Earth.

  6. Relationships between 16S-23S rRNA gene internal transcribed spacer DNA and genomic DNA similarities in the taxonomy of phototrophic bacteria

    NASA Astrophysics Data System (ADS)

    Okamura, K.; Hisada, T.; Takata, K.; Hiraishi, A.

    2013-04-01

    Rapid and accurate identification of microbial species is essential task in microbiology and biotechnology. In prokaryotic systematics, genomic DNA-DNA hybridization is the ultimate tool to determine genetic relationships among bacterial strains at the species level. However, a practical problem in this assay is that the experimental procedure is laborious and time-consuming. In recent years, information on the 16S-23S rRNA gene internal transcribed spacer (ITS) region has been used to classify bacterial strains at the species and intraspecies levels. It is unclear how much information on the ITS region can reflect the genome that contain it. In this study, therefore, we evaluate the quantitative relationship between ITS DNA and entire genomic DNA similarities. For this, we determined ITS sequences of several species of anoxygenic phototrophic bacteria belonging to the order Rhizobiales, and compared with DNA-DNA relatedness among these species. There was a high correlation between the two genetic markers. Based on the regression analysis of this relationship, 70% DNA-DNA relatedness corresponded to 92% ITS sequence similarity. This suggests the usefulness of the ITS sequence similarity as a criterion for determining the genospecies of the phototrophic bacteria. To avoid the effects of polymorphism bias of ITS on similarities, PCR products from all loci of ITS were used directly as genetic probes for comparison. The results of ITS DNA-DNA hybridization coincided well with those of genomic DNA-DNA relatedness. These collective data indicate that the whole ITS DNA-DNA similarity can be used as an alternative to genomic DNA-DNA similarity.

  7. Electroactivity of phototrophic river biofilms and constitutive cultivable bacteria.

    PubMed

    Lyautey, Emilie; Cournet, Amandine; Morin, Soizic; Boulêtreau, Stéphanie; Etcheverry, Luc; Charcosset, Jean-Yves; Delmas, François; Bergel, Alain; Garabetian, Frédéric

    2011-08-01

    Electroactivity is a property of microorganisms assembled in biofilms that has been highlighted in a variety of environments. This characteristic was assessed for phototrophic river biofilms at the community scale and at the bacterial population scale. At the community scale, electroactivity was evaluated on stainless steel and copper alloy coupons used both as biofilm colonization supports and as working electrodes. At the population scale, the ability of environmental bacterial strains to catalyze oxygen reduction was assessed by cyclic voltammetry. Our data demonstrate that phototrophic river biofilm development on the electrodes, measured by dry mass and chlorophyll a content, resulted in significant increases of the recorded potentials, with potentials of up to +120 mV/saturated calomel electrode (SCE) on stainless steel electrodes and +60 mV/SCE on copper electrodes. Thirty-two bacterial strains isolated from natural phototrophic river biofilms were tested by cyclic voltammetry. Twenty-five were able to catalyze oxygen reduction, with shifts of potential ranging from 0.06 to 0.23 V, cathodic peak potentials ranging from -0.36 to -0.76 V/SCE, and peak amplitudes ranging from -9.5 to -19.4 μA. These isolates were diversified phylogenetically (Actinobacteria, Firmicutes, Bacteroidetes, and Alpha-, Beta-, and Gammaproteobacteria) and exhibited various phenotypic properties (Gram stain, oxidase, and catalase characteristics). These data suggest that phototrophic river biofilm communities and/or most of their constitutive bacterial populations present the ability to promote electronic exchange with a metallic electrode, supporting the following possibilities: (i) development of electrochemistry-based sensors allowing in situ phototrophic river biofilm detection and (ii) production of microbial fuel cell inocula under oligotrophic conditions. PMID:21642402

  8. Populations of Anaerobic Phototrophic Bacteria in a Spartina alterniflora Salt Marsh

    PubMed Central

    Paterek, J. Robert; Paynter, M. J. B.

    1988-01-01

    Habitat-simulating media were used with the Hungate anaerobic roll tube technique to enumerate culturable anaerobic photosynthetic bacteria in sediment, tidal waters, and Spartina alterniflora plant samples collected from the salt marsh at Sapelo Island, Ga. No phototrophs were detected in samples of creekside (low marsh) sediment or in tidal waters in creekside regions. In the high marsh region, 90% of anaerobic phototrophic bacteria occurred in the top 5 mm of sediment and none were detected below 6 mm. There was a seasonal variation, with maximal populations occurring in summer and fall (mean, 4.4 × 105 phototrophs g of dry sediment−1) and minimal numbers occurring in winter (mean, 3.9 × 103 phototrophs g of dry sediment−1). During winter and late spring, phototrophs had a patchy distribution over the high marsh sediment surface. In contrast, during late summer they had a random uniform distribution. Tidal water collected over high marsh sediment contained an average of 8.7 × 102 phototrophs ml−1, with no significant seasonal variation. Anaerobic phototrophic bacteria were also cultured from the lower stem tissue of S. alterniflora growing in both the high (4.3 × 104 phototrophs g of dry tissue−1) and creekside (4.9 × 104 phototrophs g of dry tissue−1) marsh regions. Chromatium buderi, Chromatium vinosum, Thiospirillum sanguineum, Rhodospirillum molischianum, and Chlorobium phaeobacteroides were the predominant anaerobic phototrophic species cultured from high marsh sediment. The two Chromatium species were dominant. PMID:16347646

  9. Buoyant densities of phototrophic sulfur bacteria and cyanobacteria

    NASA Technical Reports Server (NTRS)

    Guerrero, R.

    1985-01-01

    The buoyant densities of bacterial cells are greatly influenced by the accumulation of intracellular reserve material. The buoyant density of phototrophic bacteria that are planktonic is of particular interest, since these organisms must remain in the photic zone of the water column for optimal growth. Separation of cells by their buoyant density may also be of use in separating and identifying organisms from a natural population. The bacteria used were obtained from pure cultures, enrichments, or samples taken directly from the environment.

  10. A physiological role for HgII during phototrophic growth

    NASA Astrophysics Data System (ADS)

    Grégoire, D. S.; Poulain, A. J.

    2016-02-01

    The bioaccumulation of toxic monomethylmercury is influenced by the redox reactions that determine the amount of mercury (Hg) substrate--HgII or Hg0 (refs ,)--that is available for methylation. Phototrophic microorganisms can reduce HgII to Hg0 (ref. ). This reduction has been linked to a mixotrophic lifestyle, in which microbes gain energy photosynthetically but acquire diverse carbon compounds for biosynthesis from the environment. Photomixotrophs must maintain redox homeostasis to disperse excess reducing power due to the accumulation of reduced enzyme cofactors. Here we report laboratory experiments in which we exposed purple bacteria growing in a bioreactor to HgII and monitored Hg0 concentrations. We show that phototrophs use HgII as an electron sink to maintain redox homeostasis. Hg0 concentrations increased only when bacteria grew phototrophically, and when bacterial enzyme cofactor ratios indicated the presence of an intracellular redox imbalance. Under such conditions, bacterial growth rates increased with increasing HgII concentrations; when alternative electron sinks were added, Hg0 production decreased. We conclude that Hg can fulfil a physiological function in bacteria, and that photomixotrophs can modify the availability of Hg to methylation sites.

  11. Mixotrophic operation of photo-bioelectrocatalytic fuel cell under anoxygenic microenvironment enhances the light dependent bioelectrogenic activity.

    PubMed

    Chandra, Rashmi; Venkata Subhash, G; Venkata Mohan, S

    2012-04-01

    Electrogenic activity of photo-bioelectrocatalytic /photo-biological fuel cell (PhFC) was evaluated in a mixotrophic mode under anoxygenic microenvironment using photosynthetic consortia as biocatalyst. An acetate rich wastewater was used as anolyte for harnessing energy along with additional treatment. Mixotrophic operation facilitated good electrogenic activity and wastewater treatment associated with biomass growth. PhFC operation documented feasible microenvironment for the growth of photosynthetic bacteria compared to algae which was supported by pigment (total chlorophyll and bacteriochlorophyll) and diversity analysis. Pigment data also illustrated the association between bacterial and algal species. The synergistic interaction between anoxygenic and oxygenic photosynthesis was found to be suitable for PhFC operation. Light dependent deposition of electrons at electrode was relatively higher compared to dark dependent electron deposition under anoxygenic condition. PhFC documented for good volatile fatty acids removal by utilizing them as electron donor. Bioelectrochemical behavior of PhFC was evaluated by voltammetric and chronoamperometry analysis. PMID:22297047

  12. Regulation of nap Gene Expression and Periplasmic Nitrate Reductase Activity in the Phototrophic Bacterium Rhodobacter sphaeroides DSM158

    PubMed Central

    Gavira, Mónica; Roldán, M. Dolores; Castillo, Francisco; Moreno-Vivián, Conrado

    2002-01-01

    Bacterial periplasmic nitrate reductases (Nap) can play different physiological roles and are expressed under different conditions depending on the organism. Rhodobacter sphaeroides DSM158 has a Nap system, encoded by the napKEFDABC gene cluster, but nitrite formed is not further reduced because this strain lacks nitrite reductase. Nap activity increases in the presence of nitrate and oxygen but is unaffected by ammonium. Reverse transcription-PCR and Northern blots demonstrated that the napKEFDABC genes constitute an operon transcribed as a single 5.5-kb product. Northern blots and nap-lacZ fusions revealed that nap expression is threefold higher under aerobic conditions but is regulated by neither nitrate nor ammonium, although it is weakly induced by nitrite. On the other hand, nitrate but not nitrite causes a rapid enzyme activation, explaining the higher Nap activity found in nitrate-grown cells. Translational nap′-′lacZ fusions reveal that the napK and napD genes are not efficiently translated, probably due to mRNA secondary structures occluding the translation initiation sites of these genes. Neither butyrate nor caproate increases nap expression, although cells growing phototrophically on these reduced substrates show a very high Nap activity in vivo (nitrite accumulation is sevenfold higher than in medium with malate). Phototrophic growth on butyrate or caproate medium is severely reduced in the NapA− mutants. Taken together, these results indicate that nitrate reduction in R. sphaeroides is mainly regulated at the level of enzyme activity by both nitrate and electron supply and confirm that the Nap system is involved in redox balancing using nitrate as an ancillary oxidant to dissipate excess reductant. PMID:11872721

  13. Cultured phototrophic biofilms for phosphorus removal in wastewater treatment.

    PubMed

    Guzzon, Antonella; Bohn, Andreas; Diociaiuti, Marco; Albertano, Patrizia

    2008-10-01

    Culture experiments with phototrophic biofilms taken from the sedimentation tank of the wastewater treatment plant at the Fiumicino Airport in Rome, Italy were carried out in a prototype continuous flow incubator. Biofilms grown at varying photosynthetic photon flux density (PPFD), temperature and flow velocity were sampled at three developmental stages to quantify biofilm dry weight, chlorophyll a concentration and total cellular phosphorus content. While no coherent significant effects by flow and temperature were evidenced, maximum biofilm dry weight and phosphorous concentration significantly increased across all featured PPFDs. Maximum chlorophyll a concentration was saturated above 60 micromol m(-2)s(-1). A highly significant association between organic biomass and phosphorous content was observed for most light conditions, including a larger proportional increase of phosphorus concentration with respect to chlorophyll a at high PPFD. Up to 112 mg P m(-2)d(-1) maximal phosphorous removal rates were achieved. Elemental analysis by energy filtering transmission electron microscopy showed subcellular localization of phosphorus, confirming the accumulation in phototrophic microorganisms in biofilms grown in high light conditions. PMID:18774156

  14. Isolation of a significant fraction of non-phototroph diversity from a desert Biological Soil Crust

    DOE PAGESBeta

    Nunes da Rocha, Ulisses; Cadillo-Quiroz, Hinsby; Karaoz, Ulas; Rajeev, Lara; Klitgord, Niels; Dunn, Sean; Truong, Viet; Buenrostro, Mayra; Bowen, Benjamin P.; Garcia-Pichel, Ferran; et al

    2015-04-14

    Biological Soil Crusts (BSCs) are organosedimentary assemblages comprised of microbes and minerals in topsoil of terrestrial environments. BSCs strongly impact soil quality in dryland ecosystems (e.g., soil structure and nutrient yields) due to pioneer species such as Microcoleus vaginatus; phototrophs that produce filaments that bind the soil together, and support an array of heterotrophic microorganisms. These microorganisms in turn contribute to soil stability and biogeochemistry of BSCs. Non-cyanobacterial populations of BSCs are less well known than cyanobacterial populations. Therefore, we attempted to isolate a broad range of numerically significant and phylogenetically representative BSC aerobic heterotrophs. Combining simple pre-treatments (hydration ofmore » BSCs under dark and light) and isolation strategies (media with varying nutrient availability and protection from oxidative stress) we recovered 402 bacterial and one fungal isolate in axenic culture, which comprised 116 phylotypes (at 97% 16S rRNA gene sequence homology), 115 bacterial and one fungal. Each medium enriched a mostly distinct subset of phylotypes, and cultivated phylotypes varied due to the BSC pre-treatment. The fraction of the total phylotype diversity isolated, weighted by relative abundance in the community, was determined by the overlap between isolate sequences and OTUs reconstructed from metagenome or metatranscriptome reads. Together, more than 8% of relative abundance of OTUs in the metagenome was represented by our isolates, a cultivation efficiency much larger than typically expected from most soils. We conclude that simple cultivation procedures combined with specific pre-treatment of samples afford a significant reduction in the culturability gap, enabling physiological and metabolic assays that rely on ecologically relevant axenic cultures.« less

  15. Isolation of a significant fraction of non-phototroph diversity from a desert Biological Soil Crust

    PubMed Central

    Nunes da Rocha, Ulisses; Cadillo-Quiroz, Hinsby; Karaoz, Ulas; Rajeev, Lara; Klitgord, Niels; Dunn, Sean; Truong, Viet; Buenrostro, Mayra; Bowen, Benjamin P.; Garcia-Pichel, Ferran; Mukhopadhyay, Aindrila; Northen, Trent R.; Brodie, Eoin L.

    2015-01-01

    Biological Soil Crusts (BSCs) are organosedimentary assemblages comprised of microbes and minerals in topsoil of terrestrial environments. BSCs strongly impact soil quality in dryland ecosystems (e.g., soil structure and nutrient yields) due to pioneer species such as Microcoleus vaginatus; phototrophs that produce filaments that bind the soil together, and support an array of heterotrophic microorganisms. These microorganisms in turn contribute to soil stability and biogeochemistry of BSCs. Non-cyanobacterial populations of BSCs are less well known than cyanobacterial populations. Therefore, we attempted to isolate a broad range of numerically significant and phylogenetically representative BSC aerobic heterotrophs. Combining simple pre-treatments (hydration of BSCs under dark and light) and isolation strategies (media with varying nutrient availability and protection from oxidative stress) we recovered 402 bacterial and one fungal isolate in axenic culture, which comprised 116 phylotypes (at 97% 16S rRNA gene sequence homology), 115 bacterial and one fungal. Each medium enriched a mostly distinct subset of phylotypes, and cultivated phylotypes varied due to the BSC pre-treatment. The fraction of the total phylotype diversity isolated, weighted by relative abundance in the community, was determined by the overlap between isolate sequences and OTUs reconstructed from metagenome or metatranscriptome reads. Together, more than 8% of relative abundance of OTUs in the metagenome was represented by our isolates, a cultivation efficiency much larger than typically expected from most soils. We conclude that simple cultivation procedures combined with specific pre-treatment of samples afford a significant reduction in the culturability gap, enabling physiological and metabolic assays that rely on ecologically relevant axenic cultures. PMID:25926821

  16. Isolation of a significant fraction of non-phototroph diversity from a desert Biological Soil Crust

    SciTech Connect

    Nunes da Rocha, Ulisses; Cadillo-Quiroz, Hinsby; Karaoz, Ulas; Rajeev, Lara; Klitgord, Niels; Dunn, Sean; Truong, Viet; Buenrostro, Mayra; Bowen, Benjamin P.; Garcia-Pichel, Ferran; Mukhopadhyay, Aindrila; Northen, Trent R.; Brodie, Eoin L.

    2015-04-14

    Biological Soil Crusts (BSCs) are organosedimentary assemblages comprised of microbes and minerals in topsoil of terrestrial environments. BSCs strongly impact soil quality in dryland ecosystems (e.g., soil structure and nutrient yields) due to pioneer species such as Microcoleus vaginatus; phototrophs that produce filaments that bind the soil together, and support an array of heterotrophic microorganisms. These microorganisms in turn contribute to soil stability and biogeochemistry of BSCs. Non-cyanobacterial populations of BSCs are less well known than cyanobacterial populations. Therefore, we attempted to isolate a broad range of numerically significant and phylogenetically representative BSC aerobic heterotrophs. Combining simple pre-treatments (hydration of BSCs under dark and light) and isolation strategies (media with varying nutrient availability and protection from oxidative stress) we recovered 402 bacterial and one fungal isolate in axenic culture, which comprised 116 phylotypes (at 97% 16S rRNA gene sequence homology), 115 bacterial and one fungal. Each medium enriched a mostly distinct subset of phylotypes, and cultivated phylotypes varied due to the BSC pre-treatment. The fraction of the total phylotype diversity isolated, weighted by relative abundance in the community, was determined by the overlap between isolate sequences and OTUs reconstructed from metagenome or metatranscriptome reads. Together, more than 8% of relative abundance of OTUs in the metagenome was represented by our isolates, a cultivation efficiency much larger than typically expected from most soils. We conclude that simple cultivation procedures combined with specific pre-treatment of samples afford a significant reduction in the culturability gap, enabling physiological and metabolic assays that rely on ecologically relevant axenic cultures.

  17. Elucidating temporal resource allocation and diurnal dynamics in phototrophic metabolism using conditional FBA

    PubMed Central

    Rügen, Marco; Bockmayr, Alexander; Steuer, Ralf

    2015-01-01

    The computational analysis of phototrophic growth using constraint-based optimization requires to go beyond current time-invariant implementations of flux-balance analysis (FBA). Phototrophic organisms, such as cyanobacteria, rely on harvesting the sun’s energy for the conversion of atmospheric CO2 into organic carbon, hence their metabolism follows a strongly diurnal lifestyle. We describe the growth of cyanobacteria in a periodic environment using a new method called conditional FBA. Our approach enables us to incorporate the temporal organization and conditional dependencies into a constraint-based description of phototrophic metabolism. Specifically, we take into account that cellular processes require resources that are themselves products of metabolism. Phototrophic growth can therefore be formulated as a time-dependent linear optimization problem, such that optimal growth requires a differential allocation of resources during different times of the day. Conditional FBA then allows us to simulate phototrophic growth of an average cell in an environment with varying light intensity, resulting in dynamic time-courses for all involved reaction fluxes, as well as changes in biomass composition over a diurnal cycle. Our results are in good agreement with several known facts about the temporal organization of phototrophic growth and have implications for further analysis of resource allocation problems in phototrophic metabolism. PMID:26496972

  18. Teaching Aerobic Fitness Concepts.

    ERIC Educational Resources Information Center

    Sander, Allan N.; Ratliffe, Tom

    2002-01-01

    Discusses how to teach aerobic fitness concepts to elementary students. Some of the K-2 activities include location, size, and purpose of the heart and lungs; the exercise pulse; respiration rate; and activities to measure aerobic endurance. Some of the 3-6 activities include: definition of aerobic endurance; heart disease risk factors;…

  19. Phototrophic microorganisms in biofilm samples from Vernjika Cave, Serbia

    NASA Astrophysics Data System (ADS)

    Popović, Slađana; Jovanović, Jelena; Predojević, Dragana; Trbojević, Ivana; Blagojević, Ana; Subakov Simić, Gordana

    2016-04-01

    Caves represent specific natural monuments in terms of structure, complexity and beauty which can be found worldwide. Even though they are considered extreme environments, they are still a unique habitat for a large number of organisms that grow and proliferate here. Often can be seen that the cave walls are differently coloured as a consequence of the biofilm development. Biofilms represent complex communities of microorganisms that can develop on different kind of surfaces, including various rock surfaces. Each microbe species play a different role in a community, but their development on stone surfaces can cause substantial damage to the substrates through different mechanisms of biodeterioration and degradation. There is an increased interest in the phototrophic component of biofilms (aerophytic cyanobacteria and algae), especially cyanobacteria, an ancient microorganisms capable to survive the most diverse extreme conditions. These phototrophs can easily be found at cave entrances illuminated by direct or indirect sunlight and areas near artificial lights. Cyanobacteria and algae were investigated in biofilm samples taken from the entrance of Vernjika Cave in Eastern Serbia. Cyanobacteria, Chlorophyta and Bacillariophyta were documented, with Cyanobacteria as a group with the highest number of recorded taxa. Chroococcalean species were the most diverse with the most frequently encountered species from the genus Gloeocapsa. Phormidium and Nostoc species were commonly recorded Oscillatoriales and Nostocles, respectively. Among Oscillatoriales species, it was noticed that one Phormidium species precipitates CaCO3 on it's sheats. Trebouxia sp. and Desmococcus olivaceus were frequently documented Chlorophyta, and representatives of Bacillariophyta were exclusively aerophytic taxa, mostly belonging to the genera Luticola and Humidophila. Measured ecological parameters, temperature and relative humidity, were influenced by the external climatic changes, while light

  20. Light-enhanced bioaccumulation of molybdenum by nitrogen-deprived recombinant anoxygenic photosynthetic bacterium Rhodopseudomonas palustris.

    PubMed

    Naito, Taki; Sachuronggui; Ueki, Masayoshi; Maeda, Isamu

    2016-01-01

    As molybdenum (Mo) is an indispensable metal for plant nitrogen metabolisms, accumulation of dissolved Mo into bacterial cells may connect to the development of bacterial fertilizers that promote plant growth. In order to enhance Mo bioaccumulation, nitrogen removal and light illumination were examined in anoxygenic photosynthetic bacteria (APB) because APB possess Mo nitrogenase whose synthesis is strictly regulated by ammonium ion concentration. In addition, an APB, Rhodopseudomonas palustris, transformed with a gene encoding Mo-responsive transcriptional regulator ModE was constructed. Mo content was most markedly enhanced by the removal of ammonium ion from medium and light illumination while their effects on other metal contents were limited. Increases in contents of trace metals including Mo by the genetic modification were observed. Thus, these results demonstrated an effective way to enrich Mo in the bacterial cells by the culture conditions and genetic modification. PMID:26376718

  1. The evolution of glutathione metabolism in phototrophic microorganisms

    NASA Technical Reports Server (NTRS)

    Fahey, R. C.; Buschbacher, R. M.; Newton, G. L.

    1987-01-01

    Of the many roles ascribed to glutathione (GSH) the one most clearly established is its role in the protection of higher eucaryotes against oxygen toxicity through destruction of thiol-reactive oxygen byproducts. If this is the primary function of GSH then GSH metabolism should have evolved during or after the evolution of oxygenic photosynthesis. That many bacteria do not produce GSH is consistent with this view. In the present study we have examined the low-molecular-weight thiol composition of a variety of phototrophic microorganisms to ascertain how evolution of GSH production is related to evolution of oxygenic photosynthesis. Cells were extracted in the presence of monobromobimane (mBBr) to convert thiols to fluorescent derivatives, which were analyzed by high-pressure liquid chromatography. Significant levels of GSH were not found in the green bacteria (Chlorobium thiosulfatophilum and Chloroflexus aurantiacus). Substantial levels of GSH were present in the purple bacteria (Chromatium vinosum, Rhodospirillum rubrum, Rhodobacter sphaeroides, and Rhodocyclus gelatinosa), the cyanobacteria [Anacystis nidulans, Microcoleus chthonoplastes S.G., Nostoc muscorum, Oscillatoria amphigranulata, Oscillatoria limnetica, Oscillatoria sp. (Stinky Spring, Utah), Oscillatoria terebriformis, Plectonema boryanum, and Synechococcus lividus], and eucaryotic algae (Chlorella pyrenoidsa, Chlorella vulgaris, Euglena gracilis, Scenedesmus obliquus, and Chlamydomonas reinhardtii). Other thiols measured included cysteine, gamma-glutamylcysteine, thiosulfate, coenzyme A, and sulfide; several unidentified thiols were also detected. Many of the organisms examined also exhibited a marked ability to reduce mBBr to syn-(methyl,methyl)bimane, an ability that was quenched by treatment with 2-pyridyl disulfide or 5,5'-bisdithio-(2-nitrobenzoic acid) prior to reaction with mBBr. These observations indicate the presence of a reducing system capable of electron transfer to mBBr and reduction of

  2. Light-Dependent Sulfide Oxidation in the Anoxic Zone of the Chesapeake Bay Can Be Explained by Small Populations of Phototrophic Bacteria

    PubMed Central

    Bennett, Alexa J.; Hanson, Thomas E.; Luther, George W.

    2015-01-01

    Microbial sulfide oxidation in aquatic environments is an important ecosystem process, as sulfide is potently toxic to aerobic organisms. Sulfide oxidation in anoxic waters can prevent the efflux of sulfide to aerobic water masses, thus mitigating toxicity. The contribution of phototrophic sulfide-oxidizing bacteria to anaerobic sulfide oxidation in the Chesapeake Bay and the redox chemistry of the stratified water column were investigated in the summers of 2011 to 2014. In 2011 and 2013, phototrophic sulfide-oxidizing bacteria closely related to Prosthecochloris species of the phylum Chlorobi were cultivated from waters sampled at and below the oxic-anoxic interface, where measured light penetration was sufficient to support populations of low-light-adapted photosynthetic bacteria. In 2012, 2013, and 2014, light-dependent sulfide loss was observed in freshly collected water column samples. In these samples, extremely low light levels caused 2- to 10-fold increases in the sulfide uptake rate over the sulfide uptake rate under dark conditions. An enrichment, CB11, dominated by Prosthecochloris species, oxidized sulfide with a Ks value of 11 μM and a Vmax value of 51 μM min−1 (mg protein−1). Using these kinetic values with in situ sulfide concentrations and light fluxes, we calculated that a small population of Chlorobi similar to those in enrichment CB11 can account for the observed anaerobic light-dependent sulfide consumption activity in natural water samples. We conclude that Chlorobi play a far larger role in the Chesapeake Bay than currently appreciated. This result has potential implications for coastal anoxic waters and expanding oxygen-minimum zones as they begin to impinge on the photic zone. PMID:26296727

  3. Phototrophic pigment diversity and picophytoplankton in permafrost thaw lakes

    NASA Astrophysics Data System (ADS)

    Przytulska, A.; Comte, J.; Crevecoeur, S.; Lovejoy, C.; Laurion, I.; Vincent, W. F.

    2016-01-01

    Permafrost thaw lakes (thermokarst lakes) are widely distributed across the northern landscape, and are known to be biogeochemically active sites that emit large amounts of carbon to the atmosphere as CH4 and CO2. However, the abundance and composition of the photosynthetic communities that fix CO2 have been little explored in this ecosystem type. In order to identify the major groups of phototrophic organisms and their controlling variables, we sampled 12 permafrost thaw lakes along a permafrost degradation gradient in northern Québec, Canada. Additional samples were taken from five rock-basin reference lakes in the region to determine if the thaw lakes differed in limnological properties and phototrophs. Phytoplankton community structure was determined by high-performance liquid chromatography analysis of their photoprotective and photosynthetic pigments, and autotrophic picoplankton concentrations were assessed by flow cytometry. One of the black-colored lakes located in a landscape of rapidly degrading palsas (permafrost mounds) was selected for high-throughput 18S rRNA sequencing to complement conclusions based on the pigment and cytometry analyses. The results showed that the limnological properties of the thaw lakes differed significantly from the reference lakes, and were more highly stratified. However, both waterbody types contained similarly diverse phytoplankton groups, with dominance of the pigment assemblages by fucoxanthin-containing taxa, as well as chlorophytes, cryptophytes and cyanobacteria. Chlorophyll a concentrations (Chl a) were correlated with total phosphorus (TP), and both were significantly higher in the thaw lakes (overall means of 3.3 µg Chl a L-1 and 34 µg TP L-1) relative to the reference lakes (2.0 µg Chl a L-1 and 8.2 µg TP L-1). Stepwise multiple regression of Chl a against the other algal pigments showed that it was largely a function of alloxanthin, fucoxanthin and Chl b (R2 = 0.85). The bottom waters of two of the thaw

  4. Phototrophic bacteria for nutrient recovery from domestic wastewater.

    PubMed

    Hülsen, Tim; Batstone, Damien J; Keller, Jürg

    2014-03-01

    The organics and nutrients in industrial and domestic wastewater are increasingly being regarded as a valuable resource for energy and nutrient recovery. Emerging concepts to redesign wastewater treatment as resource recovery systems include the use of different bacteria and algae to partition carbon and nutrients to the particulate phase through assimilation or bio-accumulation. This study evaluates the use of purple phototrophic bacteria (PPB) (also known as purple non-sulphur bacteria or PNSB) for such a biological concentration process through a series of batch tests. The key objectives are to (a) demonstrate consistent selection and enrichment of PPB using infrared light in a non-sterile medium, and (b) achieve effective partitioning of soluble organics, ammonium and phosphate into the PPB culture. PPB were successfully enriched from pre-settled domestic wastewater within 2-3 days and identified as members of the order Rhodobacterales. Under anaerobic conditions with infrared irradiation the enrichment culture was able to simultaneously remove COD (63 ± 5%), NH4-N (99.6%-0.12 ± 0.03 mgN L(-1)) and PO4-P (88%-0.8 ± 0.6 mgP L(-1)) from primary settled domestic wastewater in 24 h. In this experiment, acetate was added as an additional carbon source to demonstrate the maximal nitrogen and phosphorous elimination potential. Almost all the COD removed was assimilated into biomass rather than oxidised to CO2, with the total COD actually increasing during the batch experiments due to phototrophic synthesis. NH4-N and PO4-P were also assimilated by the biomass rather than removed through destructive oxidation or accumulation. The process offers the opportunity to concentrate organics and macronutrients from wastewater in one solids stream that can be anaerobically digested to generate energy and recover nutrients from the concentrated digestate. Technical challenges include the design of a continuous reactor system, as well as efficient delivery of

  5. Isoprenoid biosynthesis in eukaryotic phototrophs: A spotlight on algae

    SciTech Connect

    Lohr M.; Schwender J.; Polle, J. E. W.

    2012-04-01

    Isoprenoids are one of the largest groups of natural compounds and have a variety of important functions in the primary metabolism of land plants and algae. In recent years, our understanding of the numerous facets of isoprenoid metabolism in land plants has been rapidly increasing, while knowledge on the metabolic network of isoprenoids in algae still lags behind. Here, current views on the biochemistry and genetics of the core isoprenoid metabolism in land plants and in the major algal phyla are compared and some of the most pressing open questions are highlighted. Based on the different evolutionary histories of the various groups of eukaryotic phototrophs, we discuss the distribution and regulation of the mevalonate (MVA) and the methylerythritol phosphate (MEP) pathways in land plants and algae and the potential consequences of the loss of the MVA pathway in groups such as the green algae. For the prenyltransferases, serving as gatekeepers to the various branches of terpenoid biosynthesis in land plants and algae, we explore the minimal inventory necessary for the formation of primary isoprenoids and present a preliminary analysis of their occurrence and phylogeny in algae with primary and secondary plastids. The review concludes with some perspectives on genetic engineering of the isoprenoid metabolism in algae.

  6. Mushroom speleothems: Stromatolites that formed in the absence of phototrophs

    NASA Astrophysics Data System (ADS)

    Bontognali, Tomaso; D'Angeli, Ilenia; Tisato, Nicola; Vasconcelos, Crisogono; Bernasconi, Stefano; Gonzales, Esteban; DeWaele, Jo

    2016-04-01

    Unusual speleothems resembling giant mushrooms occur in Santa Catalina Cave, Cuba. Although these mineral buildups are considered a natural heritage, their composition and formation mechanism remain poorly understood. Here we characterize their morphology and mineralogy and present a model for their genesis. We propose that the mushrooms, which are mainly comprised of calcite and aragonite, formed during four different phases within an evolving cave environment. The stipe of the mushroom is an assemblage of three well-known speleothems: a stalagmite surrounded by calcite rafts that were subsequently encrusted by cave clouds (mammilaries). More peculiar is the cap of the mushroom, which is morphologically similar to cerebroid stromatolites and thrombolites of microbial origin occurring in marine environments. Scanning electron microscopy investigations of this last unit revealed the presence of fossilized extracellular polymeric substances (EPS) – the constituents of biofilms and microbial mats. These organic microstructures are mineralized with Ca-carbonate, suggesting that the mushroom cap formed through a microbially-influenced mineralization process. The existence of cerebroid Ca-carbonate buildups forming in dark caves (i.e., in the absence of phototrophs) has interesting implications for the study of fossil microbialites preserved in ancient rocks, which are today considered as one of the earliest evidence for life on Earth.

  7. Photosynthetic formation of inorganic pyrophosphate in phototrophic bacteria.

    PubMed

    Nore, B F; Nyrén, P; Salih, G F; Strid, A

    1990-04-01

    In this paper we report studies on photosynthetic formation of inorganic pyrophosphate (PPi) in three phototrophic bacteria. Formation of PPi was found in chromatophores from Rhodopseudomonas viridis but not in chromatophores from Rhodopseudomonas blastica and Rhodobacter capsulatus. The maximal rate of PPi synthesis in Rps. viridis was 0.15 μmol PPi formed/(min*μmol Bacteriochlorophyll) at 23°C. The synthesis of PPi was inhibited by electron transport inhibitors, uncouplers and fluoride, but was insensitive to oligomycin and venturicidin. The steady state rate of PPi synthesis under continuous illumination was about 15% of the steady-state rate of ATP synthesis. The synthesis of PPi after short light flashes was also studied. The yield of PPi after a single 1 ms flash was equivalent to approximately 1 μmol PPi/500 μmol Bacteriochlorophyll. In Rps. viridis chromatophores, PPi was also found to induce a membrane potential, which was sensitive to carbonyl cyanide p-trifluoromethoxyphenylhydrazone and NaF. PMID:24419767

  8. Management of aerobic vaginitis.

    PubMed

    Tempera, Gianna; Furneri, Pio Maria

    2010-01-01

    Aerobic vaginitis is a new nonclassifiable pathology that is neither specific vaginitis nor bacterial vaginosis. The diversity of this microbiological peculiarity could also explain several therapeutic failures when patients were treated for infections identified as bacterial vaginosis. The diagnosis 'aerobic vaginitis' is essentially based on microscopic examinations using a phase-contrast microscope (at ×400 magnification). The therapeutic choice for 'aerobic vaginitis' should take into consideration an antibiotic characterized by an intrinsic activity against the majority of bacteria of fecal origin, bactericidal effect and poor/absent interference with the vaginal microbiota. Regarding the therapy for aerobic vaginitis when antimicrobial agents are prescribed, not only the antimicrobial spectrum but also the presumed ecological disturbance on the anaerobic and aerobic vaginal and rectal microbiota should be taken into a consideration. Because of their very low impact on the vaginal microbiota, kanamycin or quinolones are to be considered a good choice for therapy. PMID:21051843

  9. Lasers-an effective artificial source of radiation for the cultivation of anoxygenic photosynthetic bacteria.

    PubMed

    Bertling, K; Hurse, T J; Kappler, U; Rakić, A D

    2006-06-01

    The laser diode (LD) is a unique light source that can efficiently produce all radiant energy within the narrow wavelength range used most effectively by a photosynthetic microorganism. We have investigated the use of a single type of LD for the cultivation of the well-studied anoxygenic photosynthetic bacterium, Rhodobacter capsulatus (Rb. capsulatus). An array of vertical-cavity surface-emitting lasers (VCSELs) was driven with a current of 25 mA, and delivered radiation at 860 nm with 0.4 nm linewidth. The emitted light was found to be a suitable source of radiant energy for the cultivation of Rb. capsulatus. The dependence of growth rate on incident irradiance was quantified. Despite the unusual nearly monochromatic light source used in these experiments, no significant changes in the pigment composition and in the distribution of bacteriochlorophyll between LHII and LHI-RC were detected in bacterial cells transferred from incandescent light to laser light. We were also able to show that to achieve a given growth rate in a light-limited culture, the VCSEL required only 30% of the electricity needed by an incandescent bulb, which is of great significance for the potential use of laser-devices in biotechnological applications and photobioreactor construction. PMID:16514675

  10. Environmental controls and composition of anoxygenic photoheterotrophs in ultraoligotrophic high-altitude lakes (Central Pyrenees).

    PubMed

    Caliz, Joan; Casamayor, Emilio O

    2014-04-01

    The phylogenetic composition of freshwater anoxygenic photoheterotrophs (APs) has been poorly investigated as compared with their marine counterparts. In this study, we explored a set of ultraoligotrophic cold high mountain lakes (Central Pyrenees, Spain) by both pufM gene denaturing gradient gel electrophoresis fingerprinting, and cloning and sequencing of selected lakes samples. Different ranges of limnological and physico-chemical values were explored as environmental drivers of APs richness and composition. We did not observe significant relationships between richness/diversity of pufM and any of the limnological characteristics measured or trophic status, but a negative correlation with ammonia concentration. Conductivity, pH and nitrate concentration were significantly related to changes in APs community composition, whereas lake area, altitude, temperature and trophic status did not. Most of the sequences (> 85%) had the pufM sequences of Limnohabitans (Betaproteobacteria) as the closest relative in databases, whereas less abundant clones were more closely related to Rhodobacter, Sulfitobacter and Brevundimonas (Alphaproteobacteria), in agreement with 16S rRNA gene sequences previously found in the area. Congregibacter-like Gammaproteobacteria were not detected. Comparison with available studies in inland waters showed taxonomic partitioning along salinity gradients, and Congregibacter-like sequences restricted to high saline conditions in continental water bodies. PMID:24596287

  11. Temperature modulates phototrophic periphyton response to chronic copper exposure.

    PubMed

    Lambert, Anne Sophie; Dabrin, Aymeric; Morin, Soizic; Gahou, Josiane; Foulquier, Arnaud; Coquery, Marina; Pesce, Stéphane

    2016-01-01

    Streams located in vineyard areas are highly prone to metal pollution. In a context of global change, aquatic systems are generally subjected to multi-stress conditions due to multiple chemical and/or physical pressures. Among various environmental factors that modulate the ecological effects of toxicants, special attention should be paid to climate change, which is driving an increase in extreme climate events such as sharp temperature rises. In lotic ecosystems, periphyton ensures key ecological functions such as primary production and nutrient cycling. However, although the effects of metals on microbial communities are relatively well known, there is scant data on possible interactions between temperature increase and metal pollution. Here we led a study to evaluate the influence of temperature on the response of phototrophic periphyton to copper (Cu) exposure. Winter communities, collected in a 8 °C river water, were subjected for six weeks to four thermal conditions in microcosms in presence or not of Cu (nominal concentration of 15 μg L(-1)). At the initial river temperature (8 °C), our results confirmed the chronic impact of Cu on periphyton, both in terms of structure (biomass, distribution of algal groups, diatomic composition) and function (photosynthetic efficiency). At higher temperatures (13, 18 and 23 °C), Cu effects were modulated. Indeed, temperature increase reduced Cu effects on algal biomass, algal class proportions, diatom assemblage composition and photosynthetic efficiency. This reduction of Cu effects on periphyton may be related to lower bioaccumulation of Cu and/or to selection of more Cu-tolerant species at higher temperatures. PMID:26608872

  12. Carbohydrate secretion by phototrophic communities in tidal sediments

    NASA Astrophysics Data System (ADS)

    de Winder, B.; Staats, N.; Stal, L. J.; Paterson, D. M.

    1999-09-01

    Two different benthic phototrophic communities on tidal flats were investigated for their carbohydrate content and distribution. Carbohydrates were analysed as two operationally defined fractions, related to the difficulty of extraction from the sediment matrix. Water-soluble (colloidal) and EDTA-extractable (capsular) carbohydrates were measured in a cyanobacterial mat and a diatom biofilm. The chlorophyll-specific carbohydrate content of the two communities was very different. The diatom biofilm contained up to 100 times more colloidal carbohydrate than the cyanobacterial mat. The concentrations of colloidal carbohydrates in the diatom biofilm correlated with biomass (chlorophyll-a), but this was not the case with the carbohydrate in the EDTA extract. It is proposed that the capsular carbohydrates were probably recalcitrant to mineralisation and therefore accumulated in the sediment. Neither colloidal nor EDTA-extractable carbohydrate in the cyanobacterial mat correlated with chlorophyll-a. This was probably an artefact caused by the fact that approximately 50% of the chlorophyll-a in the mat was attributed to diatoms. The characteristics of extracellular polysaccharides were investigated in laboratory cultures of the dominant organisms. Extracellular polysaccharides of the cyanobacterium Microcoleus chthonoplastes and of the diatom Navicula menisculus did not contain uronic acids. However, carboxylated sugars were found in large quantities in the capsular polysaccharides of the cyanobacterium and were present in equal ratios in the extracellular and capsular carbohydrate of the diatom Cylindrotheca closterium. Both in laboratory model systems of diatom biofilms and in situ, enhanced colloidal carbohydrate production was observed in the light. No light-dependent increase in carbohydrate concentration was found for the cyanobacterial mat. The cyanobacteria formed a mat in which the filamentous organisms entangled sand grains and attached firmly to the substratum

  13. Analysis of lipophilic pigments from a phototrophic microbial mat community by high performance liquid chromatography

    NASA Technical Reports Server (NTRS)

    Palmisano, A. C.; Cronin, S. E.; Des Marais, D. J.

    1988-01-01

    As assay for lipophilic pigments in phototrophic microbial mat communities using reverse phase-high performance liquid chromatography was developed which allows the separation of 15 carotenoids and chloropigments in a single 30 min program. Lipophilic pigments in a laminated mat from a commercial salina near Laguna Guerrero Negro, Baja California Sur, Mexico reflected their source organisms. Myxoxanthophyll, echinenone, canthaxanthin, and zeaxanthin were derived from cyanobacteria; chlorophyll c, and fucoxanthin from diatoms; chlorophyll a from cyanobacteria and diatoms; bacteriochlorophylls a and c, bacteriophaeophytin a, and gamma-carotene from Chloroflexus spp.; and beta-carotene from a variety of phototrophs. Sensitivity of detection was 0.6-6.1 ng for carotenoids and 1.7-12 ng for most chloropigments. This assay represents a significant improvement over previous analyses of lipophilic pigments in microbial mats and promises to have a wider application to other types of phototrophic communities.

  14. Teaching Aerobic Lifestyles: New Perspectives.

    ERIC Educational Resources Information Center

    Goodrick, G. Ken; Iammarino, Nicholas K.

    1982-01-01

    New approaches to teaching aerobic life-styles in secondary schools are suggested, focusing on three components: (1) the psychological benefits of aerobic activity; (2) alternative aerobic programs at nonschool locations; and (3) the development of an aerobics curriculum to help maintain an active life-style after graduation. (JN)

  15. Aerobic Conditioning Class.

    ERIC Educational Resources Information Center

    Johnson, Neil R.

    1980-01-01

    An aerobic exercise class that focuses on the conditioning of the cardiovascular and muscular systems is presented. Students complete data cards on heart rate, pulse, and exercises to be completed during the forty minute course. (CJ)

  16. [Research advances in aerobic denitrifiers].

    PubMed

    Wang, Wei; Cai, Zu-cong; Zhong, Wen-hui; Wang, Guo-xiang

    2007-11-01

    This paper reviewed the varieties and characteristics of aerobic denitrifiers, their action mechanisms, and the factors affecting aerobic denitrification. Aerobic denitrifiers mainly include Pseudomonas, Alcaligenes, Paracoccus and Bacillus, which are either aerobic or facultative aerobic, and heterotrophic. They can denitrify under aerobic conditions, with the main product being N2O. They can also convert NH4+ -N to gas product. The nitrate reductase which catalyzes the denitrification is periplasmic nitrate reductase rather than membrane-bound nitrate reductase. Dissolved oxygen concentration and C/N ratio are the main factors affecting aerobic denitrification. The main methods for screening aerobic denitrifiers, such as intermittent aeration and selected culture, were also introduced. The research advances in the application of aerobic denitrifiers in aquaculture, waste water processing, and bio-degradation of organic pollutants, as well as the contributions of aerobic denitrifiers to soil nitrogen emission were summarized. PMID:18260473

  17. Genes, Genomes, and Assemblages of Modern Anoxygenic Photosynthetic Cyanobacteria as Proxies for Ancient Cyanobacteria

    NASA Astrophysics Data System (ADS)

    Grim, S. L.; Dick, G.

    2015-12-01

    Oxygenic photosynthetic (OP) cyanobacteria were responsible for the production of O2 during the Proterozoic. However, the extent and degree of oxygenation of the atmosphere and oceans varied for over 2 Ga after OP cyanobacteria first appeared in the geologic record. Cyanobacteria capable of anoxygenic photosynthesis (AP) may have altered the trajectory of oxygenation, yet the scope of their role in the Proterozoic is not well known. Modern cyanobacterial populations from Middle Island Sinkhole (MIS), Michigan and a handful of cultured cyanobacterial strains, are capable of OP and AP. With their metabolic versatility, these microbes may approximate ancient cyanobacterial assemblages that mediated Earth's oxygenation. To better characterize the taxonomic and genetic signatures of these modern AP/OP cyanobacteria, we sequenced 16S rRNA genes and conducted 'omics analyses on cultured strains, lab mesocosms, and MIS cyanobacterial mat samples collected over multiple years from May to September. Diversity in the MIS cyanobacterial mat is low, with one member of Oscillatoriales dominating at all times. However, Planktothrix members are more abundant in the cyanobacterial community in late summer and fall. The shift in cyanobacterial community composition may be linked to seasonally changing light intensity. In lab mesocosms of MIS microbial mat, we observed a shift in dominant cyanobacterial groups as well as the emergence of Chlorobium, bacteria that specialize in AP. These shifts in microbial community composition and metabolism are likely in response to changing environmental parameters such as the availability of light and sulfide. Further research is needed to understand the impacts of the changing photosynthetic community on oxygen production and the entire microbial consortium. Our study connects genes and genomes of AP cyanobacteria to their environment, and improves understanding of cyanobacterial metabolic strategies that may have shaped Earth's redox evolution.

  18. Chloracidobacterium thermophilum gen. nov., sp. nov.: an anoxygenic microaerophilic chlorophotoheterotrophic acidobacterium.

    PubMed

    Tank, Marcus; Bryant, Donald A

    2015-05-01

    A novel anoxygenic photoheterotrophic member of the phylum Acidobacteria , Chloracidobacterium thermophilum strain B sp. nov., was isolated from a cyanobacterial enrichment culture derived from microbial mats associated with Octopus Spring, Yellowstone National Park, WY. C. thermophilum sp. nov. was a Gram-stain-negative rod (diameter, approximately 0.8-1.0 µm; variable length, approximately 2.5 µm), which formed greenish-brown liquid suspension cultures. It was a moderately thermophilic microaerophile and grew in a defined medium at 51 °C (T(opt); range 44 to 58 °C) and in the pH range 5.5 to 9.5 (pH(opt) = ~7.0). The DNA G+C content was 61.3 mol%, and phylogenetic analysis, based on the 16S rRNA sequence, showed that C. thermophilum sp. nov. belongs to subdivision 4 ( Acidobacteriaceae ) of the Acidobacteria . C. thermophilum sp. nov. was unable to synthesize branched-chain amino acids, L-lysine, and vitamin B12, which were required for growth. Although the organism lacked genes/enzymes for autotrophic carbon fixation, bicarbonate was required. Growth was stimulated by other amino acids and 2-oxoglutarate. Cells produced chlorosomes containing a diverse mixture of bacteriochlorophyll (BChl) c derivatives, and additionally, synthesized BChl a P, Chl a PD, and Zn-BChl a'P, which occurred in type-1 homodimeric reaction centres. The carotenoids included echinenone, canthaxanthin, lycopene, γ-carotene and β-carotene. C. thermophilum sp. nov. produced iso-diabolic acid as its major fatty acid and synthesized three hopanoids (diploptene, bacteriohopanetetrol and bacteriohopanetetrol cyclitol ether). Based upon its phenotypic and genotypic properties, the name Chloracidobacterium thermophilum gen. nov., sp. nov. is proposed for this isolate; the type strain is C. thermophilum strain B(T) (ATCC BAA-2647 = JCM 30199). PMID:25667398

  19. Seasonal occurrence of anoxygenic photosynthesis in Tillari and Selaulim reservoirs, Western India

    NASA Astrophysics Data System (ADS)

    Kurian, S.; Roy, R.; Repeta, D. J.; Gauns, M.; Shenoy, D. M.; Suresh, T.; Sarkar, A.; Narvenkar, G.; Johnson, C. G.; Naqvi, S. W. A.

    2011-12-01

    Phytoplankton and bacterial pigment compositions were determined by high performance liquid chromatography (HPLC) and liquid chromatography- mass spectrometry (LCMS) in two freshwater reservoirs (Tillari Dam and Selaulim Dam), which are located at the foothills of the Western Ghats in India. These reservoirs experience anoxia in the hypolimnion during summer. Water samples were collected from both reservoirs during anoxic periods while one of them (Tillari Reservoir) was also sampled in winter, when convective mixing results in well-oxygenated conditions throughout the water column. During the periods of anoxia (summer), bacteriochlorophyll (BChl) e isomers and isoreneiratene, characteristic of brown sulfur bacteria, were dominant in the anoxic (sulfidic) layer of the Tillari Reservoir under low light intensities. The winter observations showed the dominance of small cells of Chlorophyll-b containing green algae and cyanobacteria, with minor presence of fucoxanthin-containing diatoms and peridinin-containing dinoflagellates. Using total BChl-e concentration observed in June, the standing stock of brown sulfur bacteria carbon in the Tillari Reservoir was computed to be 2.4 gC m-2, which is much higher than the similar estimate for carbon derived from oxygenic photosynthesis (0.82 gC m-2). These results highlight the importance of anoxygenic photosynthetic biomass in tropical freshwater systems. The Selaulim Reservoir also displayed similar characteristics with the presence of BChl-e isomers and isorenieratene in the anoxic hypolimnion during summer. Although sulfidic conditions prevailed in the water column below the thermocline, the occurrence of photoautotrophic bacteria was restricted only to mid-depths (maximal concentration of BChl-e isomers was noted at 0.2 % of the surface incident light). This shows that the vertical distribution of photoautotrophic sulfur bacteria is primarily controlled by light penetration in the water column where the presence of H2S

  20. Physiological response of BSC phototrophic community to EPS removal

    NASA Astrophysics Data System (ADS)

    Adessi, Alessandra; Cruz de Carvalho, Ricardo; Silvestre, Susana; Rossi, Federico; Mugnai, Gianmarco; Marques da Silva, Jorge; Branquinho, Cristina; De Philippis, Roberto

    2015-04-01

    Biological Soil Crusts (BSCs) are associations between soil particles and varying proportions of cyanobacteria, heterotrophic bacteria, algae, fungi, lichens and mosses. BSCs play a major role in soil stabilization, and in drylands have been well acknowledged for mitigating desertification effects. Amongst the wide diversity of organisms that compose BSCs, cyanobacteria are the first primary producers: they colonize nutrient-limited soils, modifying the micro-environment through the excretion of large amounts of extracellular polymeric substances (EPSs). EPSs represent a huge carbon and nitrogen source for other inhabitants of the crust, are three-dimensionally spread through the first millimeters of the soil, and have a recognized role in influencing the hydrological behavior of the crust. The aim of this study was to investigate the possible role that EPSs play in the physiology of the phototrophic community residing on a light crust (without mosses or lichens, thus mainly inhabited by cyanobacteria and algae). In particular it was investigated whether the three-dimensional matrix in which EPSs are organized allowed light distribution and diffusion inside the crust, thus influencing photosynthesis. Non-invasive techniques were used to extract the polymeric matrix and to analyze photosynthetic performances in native and extracted BSC samples. Preliminary results suggested that the mild extraction protocol allowed to remove a portion of the matrix, and that this treatment revealed highly significant differences in the optical properties of the crusts comparing native and extracted samples. The extraction did not affect cell viability, as samples after the extraction were still photosynthetically active. However, chlorophyll variable fluorescence was significantly lower in the extracted samples than in native ones, and susceptibility to photoinhibition was significantly modified. Evaluating the role of the EPSs in the community is essential to further understand the

  1. Halodurantibacterium flavum gen. nov., sp. nov., a non-phototrophic bacterium isolated from an oil production mixture.

    PubMed

    Lv, Xiang-Lin; Xie, Bai-Sheng; Cai, Man; Tang, Yue-Qin; Wang, Ya-Nan; Cui, Heng-Lin; Liu, Xue-Ying; Tan, Yan; Wu, Xiao-Lei

    2015-01-01

    Three Gram-negative bacterial strains, DQW12E6-69-1(T), DQW12E61-22-1, and DQW12E6-22-1-1, were isolated from an oil production mixture from Daqing Oilfield, northeastern China. The phylogenetic analysis based on the 16S rRNA gene sequences revealed that the three strains formed a stable cluster different from the known genus in Rhodobacteraceae of Alphaproteobacteria. In addition, they were most closely related to species in genera Pararhodobacter, Rhodobacter ,and Rhodobaca with the 16S rRNA gene sequence similarities being 95.1-95.9 %. Cells of the three strains were aerobic; they do not require salt to grow but are resistant to high salinity. They could conduct chemoorganoheterotrophic growth on various carbon sources, with non-phototrophic growth observed. The genomic DNA G+C contents of the strains DQW12E6-69-1(T), DQW12E6-22-1-1, and DQW12E61-22-1 were 63.8, 63.7, and 63.6 mol%, respectively. The predominant respiratory ubiquinone of DQW12E6-69-1(T) was Q-10, and the major fatty acids were C18:1 ω7c, C(18:0), and C(10:0) 3-OH. Photosynthetic pigments and photosynthetic reaction center gene pufM were not detected. The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, unidentified glycolipid, and unidentified phospholipid. On the basis of phenotypic, genotypic, and chemotaxonomic characteristics, strains DQW12E6-69-1(T), DQW12E61-22-1, and DQW12E6-22-1-1 represent a novel genus and a novel species of the family Rhodobacteraceae. The name Halodurantibacterium flavum gen. nov., sp. nov. is proposed with strain DQW12E6-69-1(T) (=LMG 27742(T) = CGMCC 1.12756(T)) as the type strain. PMID:25240291

  2. Metagenomic evidence for the presence of phototrophic Gemmatimonadetes bacteria in diverse environments.

    PubMed

    Zeng, Yonghui; Baumbach, Jan; Barbosa, Eudes Guilherme Vieira; Azevedo, Vasco; Zhang, Chuanlun; Koblížek, Michal

    2016-02-01

    Gemmatimonadetes represents a poorly understood bacterial phylum with only a handful of cultured species. Recently, one of its few representatives, Gemmatimonas phototrophica, was found to contain purple bacterial photosynthetic reaction centres. However, almost nothing is known about the environmental distribution of phototrophic Gemmatimonadetes bacteria. To fill this gap, we took advantage of fast-growing public metagenomic databases and performed an extensive survey of metagenomes deposited into the NCBI's WGS database, the JGI's IMG webserver and the MG-RAST webserver. By employing Mg protoporphyrin IX monomethyl ester oxidative cyclase (AcsF) as a marker gene, we identified 291 AcsF fragments (24-361 amino acids long) that are closely related to G. phototrophica from 161 metagenomes originating from various habitats, including air, river waters/sediment, estuarine waters, lake waters, biofilms, plant surfaces, intertidal sediment, soils, springs and wastewater treatment plants, but none from marine waters or sediment. Based on AcsF hit counts, phototrophic Gemmatimonadetes bacteria make up 0.4-11.9% of whole phototrophic microbial communities in these habitats. Unexpectedly, an almost complete 37.9 kb long photosynthesis gene cluster with identical gene composition and arrangement to those in G. phototrophica was reconstructed from the Odense wastewater metagenome, only differing in a 7.2 kb long non-photosynthesis-gene insert. These data suggest that phototrophic Gemmatimonadetes bacteria are much more widely distributed in the environment and exhibit a higher genetic diversity than previously thought. PMID:26636755

  3. Growth of non-phototrophic microorganisms using solar energy through mineral photocatalysis.

    PubMed

    Lu, Anhuai; Li, Yan; Jin, Song; Wang, Xin; Wu, Xiao-Lei; Zeng, Cuiping; Li, Yan; Ding, Hongrui; Hao, Ruixia; Lv, Ming; Wang, Changqiu; Tang, Yueqin; Dong, Hailiang

    2012-01-01

    Phototrophy and chemotrophy are two dominant modes of microbial metabolism. To date, non-phototrophic microorganisms have been excluded from the solar light-centered phototrophic metabolism. Here we report a pathway that demonstrates a role of light in non-phototrophic microbial activity. In lab simulations, visible light-excited photoelectrons from metal oxide, metal sulfide, and iron oxide stimulated the growth of chemoautotrophic and heterotrophic bacteria. The measured bacterial growth was dependent on light wavelength and intensity, and the growth pattern matched the light absorption spectra of the minerals. The photon-to-biomass conversion efficiency was in the range of 0.13-1.90‰. Similar observations were obtained in a natural soil sample containing both bacteria and semiconducting minerals. Results from this study provide evidence for a newly identified, but possibly long-existing pathway, in which the metabolisms and growth of non-phototrophic bacteria can be stimulated by solar light through photocatalysis of semiconducting minerals. PMID:22473012

  4. Physiology and Mechanism of Phototrophic Fe(II) Oxidation by Rhodopseudomonas palustris TIE-1

    NASA Astrophysics Data System (ADS)

    Jiao, Y.; Newman, D.

    2007-12-01

    Phototrophic Fe(II)-oxidizing bacteria use electrons from ferrous iron [Fe(II)] and energy from light to drive reductive CO2 fixation. This metabolism is thought to be ancient in origin, and plays an important role in environmental iron cycling. It has been implicated in the deposition of Banded Iron Formations, a class of ancient sedimentary iron deposits. Consistent with this hypothesis, we discovered that hydrogen gas, a thermodynamically favorable electron donor to Fe(II), in an Archean atmosphere would not have inhibited phototrophic Fe(II) oxidation. To understand this physiology and the connection to BIF formation at the molecular level, the mechanisms of phototrophic Fe(II) oxidation were examined in a model organism Rhodopseudomonas palustris TIE-1. Increased expression of a putative decaheme c-type cytochrome, encoded by pioA, was observed when cells were grown under Fe(II)-oxidizing conditions. Two genes located immediately downstream of pioA in the same operon, pioB and pioC, encode a putative outer membrane beta-barrel protein and a putative high potential iron-sulfur protein, respectively. Deletion studies demonstrated that all three genes are involved in phototrophic Fe(II) oxidation. This study provides our first insight into the molecular mechanisms of this metabolism, which will be further characterized by in vitro biochemical studies.

  5. Solids Retention Time Dependent Phototrophic Growth and Population Changes in Chemostat Cultivation Using Wastewater.

    PubMed

    Shen, Qi; Wall, Judy D; Hu, Zhiqiang

    2016-01-01

    There has been renewed interest in using algae for wastewater polishing and treatment in recent years. Because solids retention time (SRT) is a key design and operating parameter in bioreactor operation, this research determined the effect of SRT on phototrophic growth and microbial population dynamics in continuous-flow chemostat systems. There was a unique feature of phototrophic growth that differed from chemotrophic growth in chemostat. It was found that the phototrophic biomass concentration increased proportionally as SRT increased from 3 to 9 days. Regardless of the change in SRT, a step function model was successfully applied with the predicted phototrophic production rate of 4.5 ± 0.9 g/m(2)·d at the light intensity of 68.5 μmol/m(2)·s. Even though the continuous-flow systems were initially seeded with a 1:1 mixture of green algae and cyanobacteria, Chlorella vulgaris always dominated (98%) in the continuous-flow chemostat systems under steady-state conditions. PMID:26803021

  6. Changes in tolerance to herbicide toxicity throughout development stages of phototrophic biofilms.

    PubMed

    Paule, A; Roubeix, V; Lauga, B; Duran, R; Delmas, F; Paul, E; Rols, J L

    2013-11-15

    Ecotoxicological experiments have been performed in laboratory-scale microcosms to investigate the sensitivity of phototrophic biofilm communities to the alachlor herbicide, in relation to the stages of phototrophic biofilm maturation (age of the phototrophic biofilms) and physical structure (intact biofilm versus recolonization). The phototrophic biofilms were initially cultivated on artificial supports in a prototype rotating annular bioreactor (RAB) with Taylor-Couette type flow under constant operating conditions. Biofilms were collected after 1.6 and 4.4 weeks of culture providing biofilms with different maturation levels, and then exposed to nominal initial alachlor concentration of 10 μg L(-1) in either intact or recolonized biofilms for 15 days in microcosms (mean time-weighted average concentration - TWAC of 5.52 ± 0.74 μg L(-1)). At the end of the exposure period, alachlor effects were monitored by a combination of biomass descriptors (ash-free dry mass - AFDM, chlorophyll a), structural molecular fingerprinting (T-RFLP), carbon utilization spectra (Biolog) and diatom species composition. We found significant effects that in terms of AFDM, alachlor inhibited growth of the intact phototrophic biofilms. No effect of alachlor was observed on diatom composition or functional and structural properties of the bacterial community regardless of whether they were intact or recolonized. The intact three-dimensional structure of the biofilm did not appear to confer protection from the effects of alachlor. Bacterial community structure and biomass level of 4.4 weeks - intact phototrophic biofilms were significantly influenced by the biofilm maturation processes rather than alachlor exposure. The diatom communities which were largely composed of mobile and colonizer life-form populations were not affected by alachlor. This study showed that the effect of alachlor (at initial concentration of 10 μg L(-1) or mean TWAC of 5.52 ± 0.74 μg L(-1)) is mainly limited to

  7. Electroactivity of Phototrophic River Biofilms and Constitutive Cultivable Bacteria ▿ †

    PubMed Central

    Lyautey, Emilie; Cournet, Amandine; Morin, Soizic; Boulêtreau, Stéphanie; Etcheverry, Luc; Charcosset, Jean-Yves; Delmas, François; Bergel, Alain; Garabetian, Frédéric

    2011-01-01

    Electroactivity is a property of microorganisms assembled in biofilms that has been highlighted in a variety of environments. This characteristic was assessed for phototrophic river biofilms at the community scale and at the bacterial population scale. At the community scale, electroactivity was evaluated on stainless steel and copper alloy coupons used both as biofilm colonization supports and as working electrodes. At the population scale, the ability of environmental bacterial strains to catalyze oxygen reduction was assessed by cyclic voltammetry. Our data demonstrate that phototrophic river biofilm development on the electrodes, measured by dry mass and chlorophyll a content, resulted in significant increases of the recorded potentials, with potentials of up to +120 mV/saturated calomel electrode (SCE) on stainless steel electrodes and +60 mV/SCE on copper electrodes. Thirty-two bacterial strains isolated from natural phototrophic river biofilms were tested by cyclic voltammetry. Twenty-five were able to catalyze oxygen reduction, with shifts of potential ranging from 0.06 to 0.23 V, cathodic peak potentials ranging from −0.36 to −0.76 V/SCE, and peak amplitudes ranging from −9.5 to −19.4 μA. These isolates were diversified phylogenetically (Actinobacteria, Firmicutes, Bacteroidetes, and Alpha-, Beta-, and Gammaproteobacteria) and exhibited various phenotypic properties (Gram stain, oxidase, and catalase characteristics). These data suggest that phototrophic river biofilm communities and/or most of their constitutive bacterial populations present the ability to promote electronic exchange with a metallic electrode, supporting the following possibilities: (i) development of electrochemistry-based sensors allowing in situ phototrophic river biofilm detection and (ii) production of microbial fuel cell inocula under oligotrophic conditions. PMID:21642402

  8. Energy positive domestic wastewater treatment: the roles of anaerobic and phototrophic technologies.

    PubMed

    Shoener, B D; Bradley, I M; Cusick, R D; Guest, J S

    2014-05-01

    The negative energy balance of wastewater treatment could be reversed if anaerobic technologies were implemented for organic carbon oxidation and phototrophic technologies were utilized for nutrient recovery. To characterize the potential for energy positive wastewater treatment by anaerobic and phototrophic biotechnologies we performed a comprehensive literature review and analysis, focusing on energy production (as kJ per capita per day and as kJ m(-3) of wastewater treated), energy consumption, and treatment efficacy. Anaerobic technologies included in this review were the anaerobic baffled reactor (ABR), anaerobic membrane bioreactor (AnMBR), anaerobic fluidized bed reactor (AFB), upflow anaerobic sludge blanket (UASB), anaerobic sequencing batch reactor (ASBR), microbial electrolysis cell (MEC), and microbial fuel cell (MFC). Phototrophic technologies included were the high rate algal pond (HRAP), photobioreactor (PBR), stirred tank reactor, waste stabilization pond (WSP), and algal turf scrubber (ATS). Average energy recovery efficiencies for anaerobic technologies ranged from 1.6% (MFC) to 47.5% (ABR). When including typical percent chemical oxygen demand (COD) removals by each technology, this range would equate to roughly 40-1200 kJ per capita per day or 110-3300 kJ m(-3) of treated wastewater. The average bioenergy feedstock production by phototrophic technologies ranged from 1200-4700 kJ per capita per day or 3400-13 000 kJ m(-3) (exceeding anaerobic technologies and, at times, the energetic content of the influent organic carbon), with usable energy production dependent upon downstream conversion to fuels. Energy consumption analysis showed that energy positive anaerobic wastewater treatment by emerging technologies would require significant reductions of parasitic losses from mechanical mixing and gas sparging. Technology targets and critical barriers for energy-producing technologies are identified, and the role of integrated anaerobic and

  9. The capacity of phototrophic sulfur bacterium Thiocapsa roseopersicina for chemosynthesis.

    PubMed

    Kondratieva, E N; Zhukov, V G; Ivanovsky, R N; Petushkova, U P; Monosov, E Z

    1976-07-01

    Purple sulfur bacterium Thiocapsa roseopersicina strain BBS requiring vitamin B12 may grow in the dark in media containing no other organic compounds. Under such conditions the cells oxidize sulfide and thiosulfate with the use of O2 and assimilate carbon dioxide. After 10--30s assimilation of NaH14CO3 about 60% of radioactivity is found in phosphorylated compounds characteristic for the reductive pentose phosphate cycle. The possibility of the function of this cycle in the dark in the presence of O2 is confirmed by the capacity of cells grown under such conditions to synthesize ribulose-1,5-diphosphate carboxylase. All this evidence suggests the ability of T. roseopersicina to change from phototrophy to aerobic chemolithoautotrophy. PMID:942280

  10. Dance--Aerobic and Anaerobic.

    ERIC Educational Resources Information Center

    Cohen, Arlette

    1984-01-01

    This article defines and explains aerobic exercise and its effects on the cardiovascular system. Various studies on dancers are cited indicating that dance is an anaerobic activity with some small degree of aerobic benefit. (DF)

  11. Aerobic Dance in Public Schools.

    ERIC Educational Resources Information Center

    Chiles, Barbara Ann; Moore, Suzanne

    1981-01-01

    Aerobic dance offers a challenging workout in a social atmosphere. Though some physical education instructors tend to exclude dance units from the curriculum, most could teach aerobic dance if they had a basic knowledge of aerobic routines. The outline for a unit to be used in the class is presented. (JN)

  12. Managing for Improved Aerobic Stability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aerobic deterioration or spoilage of silage is the result of aerobic microorganisms metabolizing components of the silage using oxygen. In the almost 40 years over which these silage conferences have been held, we have come to recognize the typical pattern of aerobic microbial development by which s...

  13. A mass-spring model unveils the morphogenesis of phototrophic Diatoma biofilms

    PubMed Central

    Celler, K.; Hödl, I.; Simone, A.; Battin, T. J.; Picioreanu, C.

    2014-01-01

    Diatoms often dominate planktonic communities in the ocean and phototrophic biofilms in streams and rivers, greatly contributing to global biogeochemical fluxes. In pelagic ecosystems, these microscopic algae can form chain-like microcolonies, which seem advantageous for nutrient uptake and protect against grazing, and at the same time reduce sinking. Despite the capability of many diatoms to form chains, their contribution to the architecture of phototrophic biofilms remains elusive. Here we propose a computational model to simulate the growth and behaviour of Diatoma chains in contrasting flow environments. This mass-spring mechanical model captures the natural behaviour of Diatoma chains well, emphasising the relevance of chain growth and entanglement for biofilm morphogenesis. The model qualitatively describes formation of intricate dome-shaped structures and of dreadlock-type streamers as observed in nature in multidirectional and unidirectional flow, respectively. The proposed model is a useful tool to study the effect of fluid dynamics on biofilm morphogenesis. PMID:24413376

  14. An integrated approach for assessing the bioreceptivity of glazed tiles to phototrophic microorganisms.

    PubMed

    Coutinho, M L; Miller, A Z; Rogerio-Candelera, M A; Mirão, J; Cerqueira Alves, L; Veiga, J P; Águas, H; Pereira, S; Lyubchyk, A; Macedo, M F

    2016-01-01

    A laboratory-based methodology was designed to assess the bioreceptivity of glazed tiles. The experimental set-up consisted of multiple steps: manufacturing of pristine and artificially aged glazed tiles, enrichment of phototrophic microorganisms, inoculation of phototrophs on glazed tiles, incubation under optimal conditions and quantification of biomass. In addition, tile intrinsic properties were assessed to determine which material properties contributed to tile bioreceptivity. Biofilm growth and biomass were appraised by digital image analysis, colorimetry and chlorophyll a analysis. SEM, micro-Raman and micro-particle induced X-ray emission analyses were carried out to investigate the biodeteriorating potential of phototrophic microorganisms on the glazed tiles. This practical and multidisciplinary approach showed that the accelerated colonization conditions allowed different types of tile bioreceptivity to be distinguished and to be related to precise characteristics of the material. Aged tiles showed higher bioreceptivity than pristine tiles due to their higher capillarity and permeability. Moreover, biophysical deterioration caused by chasmoendolithic growth was observed on colonized tile surfaces. PMID:26900634

  15. Light Structures Phototroph, Bacterial and Fungal Communities at the Soil Surface

    PubMed Central

    Davies, Lawrence O.; Schäfer, Hendrik; Marshall, Samantha; Bramke, Irene; Oliver, Robin G.; Bending, Gary D.

    2013-01-01

    The upper few millimeters of soil harbour photosynthetic microbial communities that are structurally distinct from those of underlying bulk soil due to the presence of light. Previous studies in arid zones have demonstrated functional importance of these communities in reducing soil erosion, and enhancing carbon and nitrogen fixation. Despite being widely distributed, comparative understanding of the biodiversity of the soil surface and underlying soil is lacking, particularly in temperate zones. We investigated the establishment of soil surface communities on pasture soil in microcosms exposed to light or dark conditions, focusing on changes in phototroph, bacterial and fungal communities at the soil surface (0–3 mm) and bulk soil (3–12 mm) using ribosomal marker gene analyses. Microbial community structure changed with time and structurally similar phototrophic communities were found at the soil surface and in bulk soil in the light exposed microcosms suggesting that light can influence phototroph community structure even in the underlying bulk soil. 454 pyrosequencing showed a significant selection for diazotrophic cyanobacteria such as Nostoc punctiforme and Anabaena spp., in addition to the green alga Scenedesmus obliquus. The soil surface also harboured distinct heterotrophic bacterial and fungal communities in the presence of light, in particular, the selection for the phylum Firmicutes. However, these light driven changes in bacterial community structure did not extend to the underlying soil suggesting a discrete zone of influence, analogous to the rhizosphere. PMID:23894406

  16. Gain and Loss of Phototrophic Genes Revealed by Comparison of Two Citromicrobium Bacterial Genomes

    PubMed Central

    Zheng, Qiang; Zhang, Rui; Fogg, Paul C. M.; Beatty, J. Thomas; Wang, Yu; Jiao, Nianzhi

    2012-01-01

    Proteobacteria are thought to have diverged from a phototrophic ancestor, according to the scattered distribution of phototrophy throughout the proteobacterial clade, and so the occurrence of numerous closely related phototrophic and chemotrophic microorganisms may be the result of the loss of genes for phototrophy. A widespread form of bacterial phototrophy is based on the photochemical reaction center, encoded by puf and puh operons that typically are in a ‘photosynthesis gene cluster’ (abbreviated as the PGC) with pigment biosynthesis genes. Comparison of two closely related Citromicrobial genomes (98.1% sequence identity of complete 16S rRNA genes), Citromicrobium sp. JL354, which contains two copies of reaction center genes, and Citromicrobium strain JLT1363, which is chemotrophic, revealed evidence for the loss of phototrophic genes. However, evidence of horizontal gene transfer was found in these two bacterial genomes. An incomplete PGC (pufLMC-puhCBA) in strain JL354 was located within an integrating conjugative element, which indicates a potential mechanism for the horizontal transfer of genes for phototrophy. PMID:22558224

  17. Molecular characterization of phototrophic microorganisms in the forefield of a receding glacier in the Swiss Alps

    NASA Astrophysics Data System (ADS)

    Frey, Beat; Bühler, Lukas; Schmutz, Stefan; Zumsteg, Anita; Furrer, Gerhard

    2013-03-01

    Recently deglaciated areas are ideal environments to study soil formation and primary microbial succession where phototrophic microorganisms may play a role as primary producers. The aim of our study was to investigate the cyanobacterial and green algal community composition in three different successional stages of the Damma glacier forefield in the Swiss Alps using 16S rDNA and ITS rDNA clone libraries. Cyanobacterial target sequences varied along the glacier forefield, with the highest cyanobacterial 16S rRNA gene copies found in sparsely vegetated soils. Sequence analysis revealed that the phototrophic communities were distinct in each of the three soil environments. The majority of the cyanobacterial sequences retrieved from barren soils were related to the Oscillatoriales. The diversity in sparsely vegetated soils was low, and sequences closely related to Nostoc sp. dominated. The majority of the algal phylotypes are related to members of the Trebouxiophyceae known to live as symbiotic partners in lichens. We conclude that the community composition appears to shift markedly along the chronosequence, indicating that each soil environment selects for its phototrophic community. When cyanobacteria occur together with eukaryotic microalgae, they form a rich source of organic matter and may be important contributors of carbon in nutrient-deficient deglaciated soils.

  18. Silver nanoparticles impact phototrophic biofilm communities to a considerably higher degree than ionic silver.

    PubMed

    González, Aridane G; Mombo, Stéphane; Leflaive, Joséphine; Lamy, Alexandre; Pokrovsky, Oleg S; Rols, Jean-Luc

    2015-06-01

    Due to the significant increase in nanoparticle production and especially that of silver nanoparticles over the past decade, the toxicity of silver in both ionic (Ag(+)) and nanoparticulate (AgNPs) form must be studied in detail in order to understand their impact on natural ecosystems. A comparative study of the effect of AgNPs and ionic silver on two independent phototrophic biofilms was conducted in a rotating annular bioreactor (RAB) operating under constant conditions. The concentration of dissolved silver in the inlet solution was progressively increased every 4 days of exposure, from 0.1 to 100 μg L(-1). In the course of the 40-day experiment, biofilm samples were collected to determine the evolution of biomass, chlorophyll-a, as well as photosynthetic and heterotrophic enzymatic activities in response to silver addition. Analysis of both dissolved and particulate silver allowed quantification of the distribution coefficient and uptake rate constants. The presence of both AgNPs and Ag(+) produced significant changes in the biofilm structure, decreasing the relative percentage of Diatomophyceae and Cyanophyceae and increasing the relative percentage of Chlorophyceae. The accumulation capacity of the phototrophic biofilm with respect to ionic silver and the corresponding distribution coefficients were an order of magnitude higher than those of the phototrophic biofilm with respect to AgNPs. Higher levels of AgNPs decreased the biomass from 8.6 ± 0.2 mg cm(-2) for 0-10 μg L(-1) AgNPs to 6.0 ± 0.1 mg cm(-2) for 100 μg L(-1) added AgNPs, whereas ionic silver did not have any toxic effect on the biofilm growth up to 100 μg L(-1) of added Ag(+). At the same time, AgNPs did not significantly affect the photosynthetic activity of the biofilm surface communities compared to Ag(+). It can thus be hypothesized that negatively charged AgNPs may travel through the biofilm water channels, thereby affecting the whole biofilm structure. In contrast

  19. Air-dust-borne associations of phototrophic and hydrocarbon-utilizing microorganisms: promising consortia in volatile hydrocarbon bioremediation.

    PubMed

    Al-Bader, Dhia; Eliyas, Mohamed; Rayan, Rihab; Radwan, Samir

    2012-11-01

    Aquatic and terrestrial associations of phototrophic and heterotrophic microorganisms active in hydrocarbon bioremediation have been described earlier. The question arises: do similar consortia also occur in the atmosphere? Dust samples at the height of 15 m were collected from Kuwait City air, and analyzed microbiologically for phototrophic and heterotrophic hydrocarbon-utilizing microorganisms, which were subsequently characterized according to their 16S rRNA gene sequences. The hydrocarbon utilization potential of the heterotrophs alone, and in association with the phototrophic partners, was measured quantitatively. The chlorophyte Gloeotila sp. and the two cyanobacteria Nostoc commune and Leptolyngbya thermalis were found associated with dust, and (for comparison) the cynobacteria Leptolyngbya sp. and Acaryochloris sp. were isolated from coastal water. All phototrophic cultures harbored oil vapor-utilizing bacteria in the magnitude of 10(5) g(-1). Each phototrophic culture had its unique oil-utilizing bacteria; however, the bacterial composition in Leptolyngbya cultures from air and water was similar. The hydrocarbon-utilizing bacteria were affiliated with Acinetobacter sp., Aeromonas caviae, Alcanivorax jadensis, Bacillus asahii, Bacillus pumilus, Marinobacter aquaeolei, Paenibacillus sp., and Stenotrophomonas maltophilia. The nonaxenic cultures, when used as inocula in batch cultures, attenuated crude oil in light and dark, and in the presence of antibiotics and absence of nitrogenous compounds. Aqueous and diethyl ether extracts from the phototrophic cultures enhanced the growth of the pertinent oil-utilizing bacteria in batch cultures, with oil vapor as a sole carbon source. It was concluded that the airborne microbial associations may be effective in bioremediating atmospheric hydrocarbon pollutants in situ. Like the aquatic and terrestrial habitats, the atmosphere contains dust-borne associations of phototrophic and heterotrophic hydrocarbon

  20. Aerobic landfill bioreactor

    DOEpatents

    Hudgins, Mark P; Bessette, Bernard J; March, John C; McComb, Scott T.

    2002-01-01

    The present invention includes a system of decomposing municipal solid waste (MSW) within a landfill by converting the landfill to aerobic degradation in the following manner: (1) injecting air via the landfill leachate collection system (2) injecting air via vertical air injection wells installed within the waste mass; (3) applying leachate to the waste mass using a pressurized drip irrigation system; (4) allowing landfill gases to vent; and (5) adjusting air injection and recirculated leachate to achieve a 40% to 60% moisture level and a temperature between 120.degree. F. and 140.degree. F. in steady state.

  1. Aerobic landfill bioreactor

    DOEpatents

    Hudgins, Mark P; Bessette, Bernard J; March, John; McComb, Scott T.

    2000-01-01

    The present invention includes a method of decomposing municipal solid waste (MSW) within a landfill by converting the landfill to aerobic degradation in the following manner: (1) injecting air via the landfill leachate collection system (2) injecting air via vertical air injection wells installed within the waste mass; (3) applying leachate to the waste mass using a pressurized drip irrigation system; (4) allowing landfill gases to vent; and (5) adjusting air injection and recirculated leachate to achieve a 40% to 60% moisture level and a temperature between 120.degree. F. and 140.degree. F. in steady state.

  2. Light-Dependent Aerobic Methane Oxidation Reduces Methane Emissions from Seasonally Stratified Lakes

    PubMed Central

    Oswald, Kirsten; Milucka, Jana; Brand, Andreas; Littmann, Sten; Wehrli, Bernhard; Kuypers, Marcel M. M.; Schubert, Carsten J.

    2015-01-01

    Lakes are a natural source of methane to the atmosphere and contribute significantly to total emissions compared to the oceans. Controls on methane emissions from lake surfaces, particularly biotic processes within anoxic hypolimnia, are only partially understood. Here we investigated biological methane oxidation in the water column of the seasonally stratified Lake Rotsee. A zone of methane oxidation extending from the oxic/anoxic interface into anoxic waters was identified by chemical profiling of oxygen, methane and δ13C of methane. Incubation experiments with 13C-methane yielded highest oxidation rates within the oxycline, and comparable rates were measured in anoxic waters. Despite predominantly anoxic conditions within the zone of methane oxidation, known groups of anaerobic methanotrophic archaea were conspicuously absent. Instead, aerobic gammaproteobacterial methanotrophs were identified as the active methane oxidizers. In addition, continuous oxidation and maximum rates always occurred under light conditions. These findings, along with the detection of chlorophyll a, suggest that aerobic methane oxidation is tightly coupled to light-dependent photosynthetic oxygen production both at the oxycline and in the anoxic bottom layer. It is likely that this interaction between oxygenic phototrophs and aerobic methanotrophs represents a widespread mechanism by which methane is oxidized in lake water, thus diminishing its release into the atmosphere. PMID:26193458

  3. Aerobic Fitness and School Children.

    ERIC Educational Resources Information Center

    Hinkle, J. Scott

    1997-01-01

    Provides school counselors with information on aerobic exercise (specifically running) and the psychological, behavioral, and physical benefits children obtained by participating in fitness programs. Recommends collaboration between school counselors and physical education teachers and gives a preliminary discussion of aerobic running and its…

  4. Aerobic Fitness and School Children.

    ERIC Educational Resources Information Center

    Hinkle, J. Scott

    1992-01-01

    Provides school counselors with information regarding aerobic exercise (specifically running), and the psychological, behavioral, and physical benefits children obtain by participating in fitness programs. Presents methods of collaboration between school counselors and physical education teachers. Offers preliminary discussion of aerobic running…

  5. Exercise, Animal Aerobics, and Interpretation?

    ERIC Educational Resources Information Center

    Oliver, Valerie

    1996-01-01

    Describes an aerobic activity set to music for children that mimics animal movements. Example exercises include walking like a penguin or jumping like a cricket. Stresses basic aerobic principles and designing the program at the level of children's motor skills. Benefits include reaching people who normally don't visit nature centers, and bridging…

  6. Implication of composite electrode on the functioning of photo-bioelectrocatalytic fuel cell operated with heterotrophic-anoxygenic condition.

    PubMed

    Navaneeth, B; Hari Prasad, R; Chiranjeevi, P; Chandra, Rashmi; Sarkar, Omprakesh; Verma, Anil; Subudhi, Sanjukta; Lal, Banwari; Venkata Mohan, S

    2015-06-01

    Electrode materials play a vital role in biofilm formation and electron conduction for efficient functioning of fuel cells. In the present study, graphite polymer composite electrode (GPF) was evaluated as anode for photo-bioelectrocatalytic fuel cell (PhFC; biophotovoltaic system) and compared with much studied graphite electrode (Gc) with photosynthetic bacteria as biocatalyst under anoxygenic condition. The electrogenic activity noticed in GPF (584mV; 2.67mA) was slightly lower than Gc (604mV; 2.92mA; OL2/HRT2). Consequently, COD removal observed by GPF (87.3%) was lower than Gc (91.8%). The increase in bacterial chlorophyll pigment showed a positive influence on electrogenic activity for both the electrodes. The polarization resistance (OL2 and HRT2 condition) was significantly higher for GPF (330Ω) as compared to Gc (110Ω). It is interesting to note that the performance of GPF is slightly lower than Gc based PhFC. The findings have opened avenues for composite materials for PhFC. PMID:25795447

  7. Maleimides (1 H-pyrrole-2,5-diones) as molecular indicators of anoxygenic photosynthesis in ancient water columns

    NASA Astrophysics Data System (ADS)

    Grice, Kliti; Gibbison, Robert; Atkinson, Jane E.; Schwark, Lorenz; Eckardt, Christian B.; Maxwell, James R.

    1996-10-01

    Maleimides (1 H-pyrrole-2,5-diones), degradation products of photosynthetic tetrapyrrole pigments, have been found for the first time in the polar fraction of the solvent extracts of two marine sediments deposited in restricted basins: Kupferschiefer (Permian) and Serpiano shale (Mid-Triassic). GC and GC—MS analyses of the TBDMS ( tertiary-butyldimethylsilyl) derivatives show a simple component distribution, dominated by Me Et maleimide, mainly of planktonic origin; Me n-Pr and Me i-Bu maleimides, present in low abundance, are thought on structural grounds to be derived from the bacteriochlorophylls c, d, or e of Chlorobiaceae (anoxygenic green sulfur bacteria). This is confirmed for Kupferschiefer by isotope ratio monitoring (irm) GCMS which shows them to be enriched in 13C as a result of their photosynthetic carbon assimilation, which takes place by the reversed tricarboxylic acid (TCA) cycle. The structurally more specific Me i-Bu maleimide is, however, slightly more enriched in 13C than Me n-Pr maleimide, suggesting that the latter is derived in part from reduction of the C 3-acid substituent at C-17 of phytoplanktonic chlorophyll. These results provide evidence for the existence in both depositional settings of microbial communities containing Chlorobiaceae. In turn, this indicates that there must have been periods when the water column was highly stratified and anoxia extended into the zone of light penetration.

  8. Oxygen suppresses light-driven anodic current generation by a mixed phototrophic culture.

    PubMed

    Darus, Libertus; Ledezma, Pablo; Keller, Jürg; Freguia, Stefano

    2014-12-01

    This paper describes the detrimental effect of photosynthetically evolved oxygen on anodic current generation in the presence of riboflavin upon illumination of a mixed phototrophic culture enriched from a freshwater pond at +0.6 V vs standard hydrogen electrode. In the presence of riboflavin, the phototrophic biomass in the anodic compartment produced an electrical current in response to light/dark cycles (12 h/12 h) over 12 months of operation, generating a maximum current density of 17.5 mA x m(-2) during the dark phase, whereas a much lower current of approximately 2 mA x m(-2) was generated during illumination. We found that the low current generation under light exposure was caused by high rates of reoxidation of reduced riboflavin by oxygen produced during photosynthesis. Quantification of biomass by fluorescence in situ hybridization images suggested that green algae were predominant in both the anode-based biofilm (55.1%) and the anolyte suspension (87.9%) with the remaining biovolume accounted for by bacteria. Genus-level sequencing analysis revealed that bacteria were dominated by cyanobacterium Leptolyngbia (∼35%), while the prevailing algae were Dictyosphaerium, Coelastrum, and Auxenochlorella. This study offers a key comprehension of mediator sensitivity to reoxidation by dissolved oxygen for improvement of microbial solar cell performance. PMID:25364824

  9. Carbon Metabolic Pathways in Phototrophic Bacteria and Their Broader Evolutionary Implications

    PubMed Central

    Tang, Kuo-Hsiang; Tang, Yinjie J.; Blankenship, Robert Eugene

    2011-01-01

    Photosynthesis is the biological process that converts solar energy to biomass, bio-products, and biofuel. It is the only major natural solar energy storage mechanism on Earth. To satisfy the increased demand for sustainable energy sources and identify the mechanism of photosynthetic carbon assimilation, which is one of the bottlenecks in photosynthesis, it is essential to understand the process of solar energy storage and associated carbon metabolism in photosynthetic organisms. Researchers have employed physiological studies, microbiological chemistry, enzyme assays, genome sequencing, transcriptomics, and 13C-based metabolomics/fluxomics to investigate central carbon metabolism and enzymes that operate in phototrophs. In this report, we review diverse CO2 assimilation pathways, acetate assimilation, carbohydrate catabolism, the tricarboxylic acid cycle and some key, and/or unconventional enzymes in central carbon metabolism of phototrophic microorganisms. We also discuss the reducing equivalent flow during photoautotrophic and photoheterotrophic growth, evolutionary links in the central carbon metabolic network, and correlations between photosynthetic and non-photosynthetic organisms. Considering the metabolic versatility in these fascinating and diverse photosynthetic bacteria, many essential questions in their central carbon metabolism still remain to be addressed. PMID:21866228

  10. Comparative ecology of H2 cycling in sedimentary and phototrophic ecosystems

    NASA Technical Reports Server (NTRS)

    Hoehler, Tori M.; Albert, Daniel B.; Alperin, Marc J.; Bebout, Brad M.; Martens, Christopher S.; Des Marais, David J.

    2002-01-01

    The simple biochemistry of H2 is critical to a large number of microbial processes, affecting the interaction of organisms with each other and with the environment. The sensitivity of each of these processes to H2 can be described collectively, through the quantitative language of thermodynamics. A necessary prerequisite is to understand the factors that, in turn, control H2 partial pressures. These factors are assessed for two distinctly different ecosystems. In anoxic sediments from Cape Lookout Bight (North Carolina, USA), H2 partial pressures are strictly maintained at low, steady-state levels by H2-consuming organisms, in a fashion that can be quantitatively predicted by simple thermodynamic calculations. In phototrophic microbial mats from Baja California (Mexico), H2 partial pressures are controlled by the activity of light-sensitive H2-producing organisms, and consequently fluctuate over orders of magnitude on a daily basis. The differences in H2 cycling can subsequently impact any of the H2-sensitive microbial processes in these systems. In one example, methanogenesis in Cape Lookout Bight sediments is completely suppressed through the efficient consumption of H2 by sulfate-reducing bacteria; in contrast, elevated levels of H2 prevail in the producer-controlled phototrophic system, and methanogenesis occurs readily in the presence of 40 mM sulfate.

  11. Bioengineering and Coordination of Regulatory Networks and Intracellular Complexes to Maximize Hydrogen Production by Phototrophic Microorganisms

    SciTech Connect

    Tabita, F. Robert

    2013-07-30

    In this study, the Principal Investigator, F.R. Tabita has teemed up with J. C. Liao from UCLA. This project's main goal is to manipulate regulatory networks in phototrophic bacteria to affect and maximize the production of large amounts of hydrogen gas under conditions where wild-type organisms are constrained by inherent regulatory mechanisms from allowing this to occur. Unrestrained production of hydrogen has been achieved and this will allow for the potential utilization of waste materials as a feed stock to support hydrogen production. By further understanding the means by which regulatory networks interact, this study will seek to maximize the ability of currently available “unrestrained” organisms to produce hydrogen. The organisms to be utilized in this study, phototrophic microorganisms, in particular nonsulfur purple (NSP) bacteria, catalyze many significant processes including the assimilation of carbon dioxide into organic carbon, nitrogen fixation, sulfur oxidation, aromatic acid degradation, and hydrogen oxidation/evolution. Moreover, due to their great metabolic versatility, such organisms highly regulate these processes in the cell and since virtually all such capabilities are dispensable, excellent experimental systems to study aspects of molecular control and biochemistry/physiology are available.

  12. Environmental drivers of phototrophic biofilms in an Alpine show cave (SW-Italian Alps).

    PubMed

    Piano, E; Bona, F; Falasco, E; La Morgia, V; Badino, G; Isaia, M

    2015-12-01

    The proliferation of lampenflora is a major threat for the conservation of show caves, since phototrophic organisms cause physical, chemical and aesthetic damage to speleothems. In this paper we examine the environmental factors influencing the presence and the growth of the three main photosynthetic groups composing phototrophic biofilms in the Bossea show cave (SW-Italian Alps). The presence and the primary production of cyanobacteria, diatoms and green algae were detected with BenthoTorch®, an instrument for in situ measurement of chlorophyll a concentration that has never been used before in caves. By means of different techniques of regression analysis, we highlighted the response of the three photosynthetic groups to different environmental factors. Illuminance proved to be the main factor influencing positively both the probability of the presence and the productivity of the three groups. The presence of seeping water on the substrate and the distance from the cave entrance proved to play an important role in determining patterns of colonization. By means of GIS techniques, we provide thematic maps of the cave, providing a representation of pattern of the density of the three examined photosynthetic groups within different areas of the cave. The same approach may apply to other show caves, aiming at providing suggestions for the cave management (i.e. cleaning of the cave walls and positioning of artificial lights) and reduce impact caused by tourism. PMID:26112916

  13. Soil surface colonization by phototrophic indigenous organisms, in two contrasted soils treated by formulated maize herbicide mixtures.

    PubMed

    Joly, Pierre; Misson, Benjamin; Perrière, Fanny; Bonnemoy, Frédérique; Joly, Muriel; Donnadieu-Bernard, Florence; Aguer, Jean-Pierre; Bohatier, Jacques; Mallet, Clarisse

    2014-11-01

    Soil phototrophic microorganisms, contributors to soil health and food webs, share their particular metabolism with plants. Current agricultural practices employ mixtures of pesticides to ensure the crops yields and can potentially impair these non-target organisms. However despite this environmental reality, studies dealing the susceptibility of phototrophic microorganisms to pesticide mixtures are scarce. We designed a 3 months microcosm study to assess the ecotoxicity of realistic herbicide mixtures of formulated S-metolachlor (Dual Gold Safeneur(®)), mesotrione (Callisto(®)) and nicosulfuron (Milagro(®)) on phototrophic communities of two soils (Limagne vertisol and Versailles luvisol). The soils presented different colonizing communities, with diatoms and chlorophyceae dominating communities in Limagne soil and cyanobacteria and bryophyta communities in Versailles soil. The results highlighted the strong impairment of Dual Gold Safeneur(®) treated microcosms on the biomass and the composition of both soil phototrophic communities, with no resilience after a delay of 3 months. This study also excluded any significant mixture effect on these organisms for Callisto(®) and Milagro(®) herbicides. We strongly recommend carrying on extensive soil studies on S-metolachlor and its commercial formulations, in order to reconsider its use from an ecotoxicological point of view. PMID:25129149

  14. Production and Consumption of Hydrogen in Hot Spring Microbial Mats Dominated by a Filamentous Anoxygenic Photosynthetic Bacterium

    PubMed Central

    Otaki, Hiroyo; Everroad, R. Craig; Matsuura, Katsumi; Haruta, Shin

    2012-01-01

    Microbial mats containing the filamentous anoxygenic photosynthetic bacterium Chloroflexus aggregans develop at Nakabusa hot spring in Japan. Under anaerobic conditions in these mats, interspecies interaction between sulfate-reducing bacteria as sulfide producers and C. aggregans as a sulfide consumer has been proposed to constitute a sulfur cycle; however, the electron donor utilized for microbial sulfide production at Nakabusa remains to be identified. In order to determine this electron donor and its source, ex situ experimental incubation of mats was explored. In the presence of molybdate, which inhibits biological sulfate reduction, hydrogen gas was released from mat samples, indicating that this hydrogen is normally consumed as an electron donor by sulfate-reducing bacteria. Hydrogen production decreased under illumination, indicating that C. aggregans also functions as a hydrogen consumer. Small amounts of hydrogen may have also been consumed for sulfur reduction. Clone library analysis of 16S rRNA genes amplified from the mats indicated the existence of several species of hydrogen-producing fermentative bacteria. Among them, the most dominant fermenter, Fervidobacterium sp., was successfully isolated. This isolate produced hydrogen through the fermentation of organic carbon. Dispersion of microbial cells in the mats resulted in hydrogen production without the addition of molybdate, suggesting that simultaneous production and consumption of hydrogen in the mats requires dense packing of cells. We propose a cyclic electron flow within the microbial mats, i.e., electron flow occurs through three elements: S (elemental sulfur, sulfide, sulfate), C (carbon dioxide, organic carbon) and H (di-hydrogen, protons). PMID:22446313

  15. Modeling the Habitat Range of Phototrophs in Yellowstone National Park: Toward the Development of a Comprehensive Fitness Landscape

    PubMed Central

    Boyd, Eric S.; Fecteau, Kristopher M.; Havig, Jeff R.; Shock, Everett L.; Peters, John W.

    2012-01-01

    The extent to which geochemical variation shapes the distribution of phototrophic metabolisms was modeled based on 439 observations in geothermal springs in Yellowstone National Park (YNP), Wyoming. Generalized additive models (GAMs) were developed to predict the distribution of phototrophic metabolism as a function of spring temperature, pH, and total sulfide. GAMs comprised of temperature explained 38.8% of the variation in the distribution of phototrophic metabolism, whereas GAMs comprised of sulfide and pH explained 19.6 and 11.2% of the variation, respectively. These results suggest that of the measured variables, temperature is the primary constraint on the distribution of phototrophs in YNP. GAMs comprised of multiple variables explained a larger percentage of the variation in the distribution of phototrophic metabolism, indicating additive interactions among variables. A GAM that combined temperature and sulfide explained the greatest variation in the dataset (53.4%) while minimizing the introduction of degrees of freedom. In an effort to verify the extent to which phototroph distribution reflects constraints on activity, we examined the influence of sulfide and temperature on dissolved inorganic carbon (DIC) uptake rates under both light and dark conditions. Light-driven DIC uptake decreased systematically with increasing concentrations of sulfide in acidic, algal-dominated systems, but was unaffected in alkaline, cyanobacterial-dominated systems. In both alkaline and acidic systems, light-driven DIC uptake was suppressed in cultures incubated at temperatures 10°C greater than their in situ temperature. Collectively, these quantitative results indicate that apart from light availability, the habitat range of phototrophs in YNP springs is defined largely by constraints imposed firstly by temperature and secondly by sulfide on the activity of these populations that inhabit the edges of the habitat range. These findings are consistent with the predictions

  16. Subaerial biofilms on granitic historic buildings: microbial diversity and development of phototrophic multi-species cultures.

    PubMed

    Vázquez-Nion, D; Rodríguez-Castro, J; López-Rodríguez, M C; Fernández-Silva, I; Prieto, B

    2016-07-01

    Microbial communities of natural subaerial biofilms developed on granitic historic buildings of a World Heritage Site (Santiago de Compostela, NW Spain) were characterized and cultured in liquid BG11 medium. Environmental barcoding through next-generation sequencing (Pacific Biosciences) revealed that the biofilms were mainly composed of species of Chlorophyta (green algae) and Ascomycota (fungi) commonly associated with rock substrata. Richness and diversity were higher for the fungal than for the algal assemblages and fungi showed higher heterogeneity among samples. Cultures derived from natural biofilms showed the establishment of stable microbial communities mainly composed of Chlorophyta and Cyanobacteria. Although most taxa found in these cultures were not common in the original biofilms, they are likely common pioneer colonizers of building stone surfaces, including granite. Stable phototrophic multi-species cultures of known microbial diversity were thus obtained and their reliability to emulate natural colonization on granite should be confirmed in further experiments. PMID:27192622

  17. Oxidative phosphorylation during glycollate metabolism in mitochondria from phototrophic Euglena gracilis.

    PubMed

    Collins, N; Brown, R H; Merrett, M J

    1975-09-01

    Mitochondria were isolated by gradient centrifugation on linear sucrose gradients from broken cell suspensions of phototrophically grown Euglena gracilis. An antimycin A-sensitive but rotenone-insensitive glycollate-dependent oxygen uptake was demonstrated in isolated mitochondria. The partial reactions of glycollate-cytochrome c oxidoreductase and cytochrome c oxidase were demonstrated by using Euglena cytochrome c as exogenous electron acceptor/donor. Isolated mitochondria contain glycollate dehydrogenase and glyoxylate-glutamate aminotransferase and oxidize exogenous glycine. A P:O ratio of 1.7 was obtained for glycollate oxidation, consistent with glycollate electrons entering the Euglena respiratory chain at the flavoprotein level. The significance of these results is discussed in relation to photorespiration in algae. PMID:813630

  18. Ecophysiology of phototrophic sulfur bacteria in lakes: Vertical distribution of planktonic populations

    NASA Technical Reports Server (NTRS)

    Guerrero, R.

    1985-01-01

    The study of purple and green sulfur bacterial populations in nature is of interest for the following reasons: (1) high quantities of biomass, with low species diversity can be collected; (2) study of planktonic life permits one to understand the mechanisms, structural as well as physiological, used to maintain their vertical position without sinking; and (3) they are capable of sulfur oxidations and reductions that act as important intermediates in the global sulfur cycle. Purple and green photosynthetic bacteria, moreover, may be responsible for certain geological deposits. Planktonic phototrophic sulfur bacteria were analyzed in relation to their vertical distribution in the water column. Factors, including competition for light, that determine their sedimentation rates and the numerical changes in species and populations were assessed.

  19. Purple phototrophic bacterium enhances stevioside yield by Stevia rebaudiana Bertoni via foliar spray and rhizosphere irrigation.

    PubMed

    Wu, Jing; Wang, Yiming; Lin, Xiangui

    2013-01-01

    This study was conducted to compare the effects of foliar spray and rhizosphere irrigation with purple phototrophic bacteria (PPB) on growth and stevioside (ST) yield of Stevia. rebaudiana. The S. rebaudiana plants were treated by foliar spray, rhizosphere irrigation, and spray plus irrigation with PPB for 10 days, respectively. All treatments enhanced growth of S. rebaudiana, and the foliar method was more efficient than irrigation. Spraying combined with irrigation increased the ST yield plant (-1) by 69.2% as compared to the control. The soil dehydrogenase activity, S. rebaudiana shoot biomass, chlorophyll content in new leaves, and soluble sugar in old leaves were affected significantly by S+I treatment, too. The PPB probably works in the rhizosphere by activating the metabolic activity of soil bacteria, and on leaves by excreting phytohormones or enhancing the activity of phyllosphere microorganisms. PMID:23825677

  20. A parallel bubble column system for the cultivation of phototrophic microorganisms.

    PubMed

    Havel, Jan; Franco-Lara, Ezequiel; Weuster-Botz, Dirk

    2008-07-01

    An incubator with up to 16 parallel bubble columns was equipped with artificial light sources assuring a light supply with a homogenous light spectrum directly above the bioreactors. Cylindrical light reflecting tubes were positioned around every single bubble column to avoid light scattering effects and to redirect the light from the top onto the cylindrical outer glass surface of each bubble column. The light reflecting tubes were equipped with light intensity filters to control the total light intensity for every single photo-bioreactor. Parallel cultivations of the unicellular obligate phototrophic cyanobacterium, Synechococcus PCC7942, were studied under different constant light intensities ranging from 20 to 102 microE m(-2)s(-1) at a constant humidified air flow rate supplemented with CO(2). PMID:18488151

  1. Enrichments for phototrophic bacteria and characterization by morphology and pigment analysis

    NASA Technical Reports Server (NTRS)

    Brune, D.

    1985-01-01

    The purpose of this investigation was to examine several sulfide containing environments for the presence of phototrophic bacteria and to obtain enriched cultures of some of the bacteria present. The field sites were Alum Rock State Park, the Palo Alto salt marsh, the bay area salt ponds, and Big Soda Lake (near Fallon, Nevada). Bacteria from these sites were characterized by microscopic examination, measurement of in vitro absorption spectra, and analysis of carotenoid pigments. Field observations at one of the bay area salt ponds, in which the salt concentration was saturating (about 30 percent NaCl) and the sediments along the shore of the pond covered with a gypsum crust, revealed a layer of purple photosynthetic bacteria under a green layer in the gypsum crust. Samples of this gypsum crust were taken to the laboratory to measure light transmission through the crust and to try to identify the purple photosynthetic bacteria present in this extremely saline environment.

  2. Distribution and Physiology of Aerobic Bacteria Containing Bacteriochlorophyll a on the East and West Coasts of Australia †

    PubMed Central

    Shiba, Tsuneo; Shioi, Yuzo; Takamiya, Ken-Ichiro; Sutton, David C.; Wilkinson, Clive R.

    1991-01-01

    Aerobic heterotrophic bacteria containing bacteriochlorophyll were isolated from specimens from a wide variety of marine environments on the west (Shark Bay, Lake Clifton, Lake Heyward, and Perth) and east (near Townsville and Brisbane) coasts of Australia. The bacteria were found in a high proportion (10 to 30%) of the total heterotrophic bacterial strains isolated from marine algae, seagrasses, stromatolites, the epiphytes on stromatolites, seawater, and sands; in some cases they constituted up to 49% of the total. This is much higher than the previous report of 6% from Japan. A high percentage, 13%, was also found in the seawater of Hamelin Pool, at Shark Bay, where the salinity was 66%. The number of these bacteria was generally low in seawater and sands, with a few exceptions. There were no aerobic bacteriochlorophyll-containing bacteria on sponges or corals. The isolated strains were orange or pink, and most had absorption maxima around 800 and 850 to 870 nm, the latter range being the absorption of bacteriochlorophyll a in vivo. The maximum bacteriochlorophyll content was 1 nmol/mg (dry weight) of bacterial cells. Most of the bacteria did not grow phototrophically under anaerobic conditions in a broth medium containing succinate. Cells and cell extracts grown under aerobic conditions had photochemical activities such as reversible photooxidations of the reaction center and cytochrome(s). Some strains showed denitrifying activity. The optimal salinity for bacterial growth varied between strains. PMID:16348398

  3. Regulation of electron transfer processes affects phototrophic mat structure and activity.

    PubMed

    Ha, Phuc T; Renslow, Ryan S; Atci, Erhan; Reardon, Patrick N; Lindemann, Stephen R; Fredrickson, James K; Call, Douglas R; Beyenal, Haluk

    2015-01-01

    Phototrophic microbial mats are among the most diverse ecosystems in nature. These systems undergo daily cycles in redox potential caused by variations in light energy input and metabolic interactions among the microbial species. In this work, solid electrodes with controlled potentials were placed under mats to study the electron transfer processes between the electrode and the microbial mat. The phototrophic microbial mat was harvested from Hot Lake, a hypersaline, epsomitic lake located near Oroville (Washington, USA). We operated two reactors: graphite electrodes were polarized at potentials of -700 mVAg/AgCl [cathodic (CAT) mat system] and +300 mVAg/AgCl [anodic (AN) mat system] and the electron transfer rates between the electrode and mat were monitored. We observed a diel cycle of electron transfer rates for both AN and CAT mat systems. Interestingly, the CAT mats generated the highest reducing current at the same time points that the AN mats showed the highest oxidizing current. To characterize the physicochemical factors influencing electron transfer processes, we measured depth profiles of dissolved oxygen (DO) and sulfide in the mats using microelectrodes. We further demonstrated that the mat-to-electrode and electrode-to-mat electron transfer rates were light- and temperature-dependent. Using nuclear magnetic resonance (NMR) imaging, we determined that the electrode potential regulated the diffusivity and porosity of the microbial mats. Both porosity and diffusivity were higher in the CAT mats than in the AN mats. We also used NMR spectroscopy for high-resolution quantitative metabolite analysis and found that the CAT mats had significantly higher concentrations of osmoprotectants such as betaine and trehalose. Subsequently, we performed amplicon sequencing across the V4 region of the 16S rRNA gene of incubated mats to understand the impact of electrode potential on microbial community structure. These data suggested that variation in the

  4. Regulation of electron transfer processes affects phototrophic mat structure and activity

    PubMed Central

    Ha, Phuc T.; Renslow, Ryan S.; Atci, Erhan; Reardon, Patrick N.; Lindemann, Stephen R.; Fredrickson, James K.; Call, Douglas R.; Beyenal, Haluk

    2015-01-01

    Phototrophic microbial mats are among the most diverse ecosystems in nature. These systems undergo daily cycles in redox potential caused by variations in light energy input and metabolic interactions among the microbial species. In this work, solid electrodes with controlled potentials were placed under mats to study the electron transfer processes between the electrode and the microbial mat. The phototrophic microbial mat was harvested from Hot Lake, a hypersaline, epsomitic lake located near Oroville (Washington, USA). We operated two reactors: graphite electrodes were polarized at potentials of -700 mVAg/AgCl [cathodic (CAT) mat system] and +300 mVAg/AgCl [anodic (AN) mat system] and the electron transfer rates between the electrode and mat were monitored. We observed a diel cycle of electron transfer rates for both AN and CAT mat systems. Interestingly, the CAT mats generated the highest reducing current at the same time points that the AN mats showed the highest oxidizing current. To characterize the physicochemical factors influencing electron transfer processes, we measured depth profiles of dissolved oxygen (DO) and sulfide in the mats using microelectrodes. We further demonstrated that the mat-to-electrode and electrode-to-mat electron transfer rates were light- and temperature-dependent. Using nuclear magnetic resonance (NMR) imaging, we determined that the electrode potential regulated the diffusivity and porosity of the microbial mats. Both porosity and diffusivity were higher in the CAT mats than in the AN mats. We also used NMR spectroscopy for high-resolution quantitative metabolite analysis and found that the CAT mats had significantly higher concentrations of osmoprotectants such as betaine and trehalose. Subsequently, we performed amplicon sequencing across the V4 region of the 16S rRNA gene of incubated mats to understand the impact of electrode potential on microbial community structure. These data suggested that variation in the

  5. The Epsomitic Phototrophic Microbial Mat of Hot Lake, Washington. Community Structural Responses to Seasonal Cycling

    SciTech Connect

    Lindemann, Stephen R.; Moran, James J.; Stegen, James C.; Renslow, Ryan S.; Hutchison, Janine R.; Cole, Jessica K.; Dohnalkova, Alice; Tremblay, Julien; Singh, Kanwar; Malfatti, Stephanie; Chen, Feng; Tringe, Susannah; Beyenal, Haluk; Fredrickson, Jim K.

    2013-11-13

    Phototrophic microbial mats are compact ecosystems composed of highly interactive organisms in which energy and element cycling take place over millimeter-to-centimeter-scale distances. Although microbial mats are common in hypersaline environments, they have not been extensively characterized in systems dominated by divalent ions. Hot Lake is a meromictic, epsomitic lake that occupies a small, endorheic basin in north-central Washington. The lake harbors a benthic, phototrophic mat that assembles each spring, disassembles each fall, and is subject to greater than tenfold variation in salinity (primarily Mg2+ and SO2-4) and irradiation over the annual cycle. We examined spatiotemporal variation in the mat community at five time points throughout the annual cycle with respect to prevailing physicochemical parameters by amplicon sequencing of the V4 region of the 16S rRNA gene coupled to near-full-length 16S RNA clone sequences. The composition of these microbial communities was relatively stable over the seasonal cycle and included dominant populations of Cyanobacteria, primarily a group IV cyanobacterium (Leptolyngbya), and Alphaproteobacteria (specifically, members of Rhodobacteraceae and Geminicoccus). Members of Gammaproteobacteria (e.g., Thioalkalivibrio and Halochromatium) and Deltaproteobacteria (e.g., Desulfofustis) that are likely to be involved in sulfur cycling peaked in summer and declined significantly by mid-fall, mirroring larger trends in mat community richness and evenness. Phylogenetic turnover analysis of abundant phylotypes employing environmental metadata suggests that seasonal shifts in light variability exert a dominant influence on the composition of Hot Lake microbial mat communities. The seasonal development and organization of these structured microbial mats provide opportunities for analysis of the temporal and physical dynamics that feed back to community function.

  6. Comparative Ecology of H2 Cycling in Organotrophic and Phototrophic Ecosystems

    NASA Technical Reports Server (NTRS)

    Hoehler, Tori M.; Alperin, Marc J.; Albert, Daniel B.; Bebout, Brad M.; Martens, Christopher S.; DesMarais, David J.; DeVincenzi, Don (Technical Monitor)

    2001-01-01

    The simple biochemistry of H2 is critical to a large number of microbial processes, affecting the interaction of organisms with each other and with the environment. The sensitivity of these many processes to H2 can be described quantitatively, at a basic thermodynamic level. This shared dependence on H2 may provide a means for interpreting the ecology and system-level biogeochemistry of widely variant microbial ecosystems on a common (and quantitative) level. Understanding the factors that control H2 itself is a critical prerequisite. Here, we examine two ecosystems that vary widely with respect to H2 cycling. In anoxic, 'organotrophic' sediments from Cape Lookout Bight (North Carolina, USA), H2 partial pressures are strictly maintained at low, steady-state levels by H2-consuming organisms, in a fashion that can be quantitatively predicted by simple thermodynamic calculations. In phototrophic microbial mats from Baja, Mexico, H2 partial pressures are instead controlled by the activity of light-sensitive H2-producing organisms. In consequence, H2 partial pressures within the system fluctuate by orders of magnitude on hour-long time scales. The differences in H2 cycling subsequently impact H2-sensitive microbial processes, such as methanogenesis. For example, the presence of sulfate in the organotrophic system always yielded low levels of H2 that were inhibitory to methanogenesis; however, the elevated levels of H2 in the phototrophic system favored methane production at significant levels, even in the presence of high sulfate concentrations. The myriad of other H2-sensitive microbial processes are expected to exhibit similar behavior.

  7. The epsomitic phototrophic microbial mat of Hot Lake, Washington: community structural responses to seasonal cycling

    PubMed Central

    Lindemann, Stephen R.; Moran, James J.; Stegen, James C.; Renslow, Ryan S.; Hutchison, Janine R.; Cole, Jessica K.; Dohnalkova, Alice C.; Tremblay, Julien; Singh, Kanwar; Malfatti, Stephanie A.; Chen, Feng; Tringe, Susannah G.; Beyenal, Haluk; Fredrickson, James K.

    2013-01-01

    Phototrophic microbial mats are compact ecosystems composed of highly interactive organisms in which energy and element cycling take place over millimeter-to-centimeter-scale distances. Although microbial mats are common in hypersaline environments, they have not been extensively characterized in systems dominated by divalent ions. Hot Lake is a meromictic, epsomitic lake that occupies a small, endorheic basin in north-central Washington. The lake harbors a benthic, phototrophic mat that assembles each spring, disassembles each fall, and is subject to greater than tenfold variation in salinity (primarily Mg2+ and SO2−4) and irradiation over the annual cycle. We examined spatiotemporal variation in the mat community at five time points throughout the annual cycle with respect to prevailing physicochemical parameters by amplicon sequencing of the V4 region of the 16S rRNA gene coupled to near-full-length 16S RNA clone sequences. The composition of these microbial communities was relatively stable over the seasonal cycle and included dominant populations of Cyanobacteria, primarily a group IV cyanobacterium (Leptolyngbya), and Alphaproteobacteria (specifically, members of Rhodobacteraceae and Geminicoccus). Members of Gammaproteobacteria (e.g., Thioalkalivibrio and Halochromatium) and Deltaproteobacteria (e.g., Desulfofustis) that are likely to be involved in sulfur cycling peaked in summer and declined significantly by mid-fall, mirroring larger trends in mat community richness and evenness. Phylogenetic turnover analysis of abundant phylotypes employing environmental metadata suggests that seasonal shifts in light variability exert a dominant influence on the composition of Hot Lake microbial mat communities. The seasonal development and organization of these structured microbial mats provide opportunities for analysis of the temporal and physical dynamics that feed back to community function. PMID:24312082

  8. The Transition from Aerobic to Anaerobic Metabolism.

    ERIC Educational Resources Information Center

    Skinner, James S.; McLellan, Thomas H.

    1980-01-01

    The transition from aerobic to anaerobic metabolism is discussed. More research is needed on different kinds of athletes and athletic activities and how they may affect aerobic and anaerobic metabolisms. (CJ)

  9. "Aerobic" Writing: A Writing Practice Model.

    ERIC Educational Resources Information Center

    Crisp, Sally Chandler

    "Aerobic writing" is a writing center strategy designed to keep students in writing "shape." Like aerobic exercise, aerobic writing is sustained for a certain length of time and done on a regular basis at prescribed time intervals. The program requires students to write at least two times a week for approximately an hour each time. Students write,…

  10. Arthritis and Aerobic Exercise: A Review.

    ERIC Educational Resources Information Center

    Ike, Robert W.; And Others

    1989-01-01

    Arthritic patients who regularly do aerobic exercise make significant gains in aerobic and functional status, and in subjective areas like pain tolerance and mood. Still, they are often advised to curtail physical activity. Guidelines are presented for physicians prescribing aerobic exercise. An exercise tolerance test is recommended. (SM)

  11. Quantifying Microbial Diversity: Morphotypes, 16S rRNA Genes, and Carotenoids of Oxygenic Phototrophs in Microbial Mats

    PubMed Central

    Nübel, Ulrich; Garcia-Pichel, Ferran; Kühl, Michael; Muyzer, Gerard

    1999-01-01

    We quantified the diversity of oxygenic phototrophic microorganisms present in eight hypersaline microbial mats on the basis of three cultivation-independent approaches. Morphological diversity was studied by microscopy. The diversity of carotenoids was examined by extraction from mat samples and high-pressure liquid chromatography analysis. The diversity of 16S rRNA genes from oxygenic phototrophic microorganisms was investigated by extraction of total DNA from mat samples, amplification of 16S rRNA gene segments from cyanobacteria and plastids of eukaryotic algae by phylum-specific PCR, and sequence-dependent separation of amplification products by denaturing-gradient gel electrophoresis. A numerical approach was introduced to correct for crowding the results of chromatographic and electrophoretic analyses. Diversity estimates typically varied up to twofold among mats. The congruence of richness estimates and Shannon-Weaver indices based on numbers and proportional abundances of unique morphotypes, 16S rRNA genes, and carotenoids unveiled the underlying diversity of oxygenic phototrophic microorganisms in the eight mat communities studied. PMID:9925563

  12. Regulation of electron transfer processes affects phototrophic mat structure and activity

    SciTech Connect

    Ha, Phuc T.; Renslow, Ryan S.; Atci, Erhan; Reardon, Patrick N.; Lindemann, Stephen R.; Fredrickson, James K.; Call, Douglas R.; Beyenal, Haluk

    2015-09-03

    Phototrophic microbial mats are among the most diverse ecosystems in nature. These systems undergo daily cycles in redox potential caused by variations in light energy input and metabolic interactions among the microbial species. In this work, solid electrodes with controlled potentials were placed under mats to study the electron transfer processes between the electrode and the microbial mat. The phototrophic microbial mat was harvested from Hot Lake, a hypersaline, epsomitic lake located near Oroville (Washington, USA). We operated two reactors: graphite electrodes were polarized at potentials of -700 mVAg/AgCl [cathodic (CAT) mat system] and +300 mVAg/AgCl [anodic (AN) mat system] and the electron transfer rates between the electrode and mat were monitored. We observed a diel cycle of electron transfer rates for both AN and CAT mat systems. Interestingly, the CAT mats generated the highest reducing current at the same time points that the AN mats showed the highest oxidizing current. To characterize the physicochemical factors influencing electron transfer processes, we measured depth profiles of dissolved oxygen (DO) and sulfide in the mats using microelectrodes. We further demonstrated that the mat-to-electrode and electrode-to-mat electron transfer rates were light- and temperature-dependent. Using nuclear magnetic resonance (NMR) imaging, we determined that the electrode potential regulated the diffusivity and porosity of the microbial mats. Both porosity and diffusivity were higher in the CAT mats than in the AN mats. We also used NMR spectroscopy for high-resolution quantitative metabolite analysis and found that the CAT mats had significantly higher concentrations of osmoprotectants such as betaine and trehalose. Subsequently, we performed amplicon sequencing across the V4 region of the 16S rRNA gene of incubated mats to understand the impact of electrode potential on microbial community structure. In conclusion, these data suggested

  13. Regulation of electron transfer processes affects phototrophic mat structure and activity

    DOE PAGESBeta

    Ha, Phuc T.; Renslow, Ryan S.; Atci, Erhan; Reardon, Patrick N.; Lindemann, Stephen R.; Fredrickson, James K.; Call, Douglas R.; Beyenal, Haluk

    2015-09-03

    Phototrophic microbial mats are among the most diverse ecosystems in nature. These systems undergo daily cycles in redox potential caused by variations in light energy input and metabolic interactions among the microbial species. In this work, solid electrodes with controlled potentials were placed under mats to study the electron transfer processes between the electrode and the microbial mat. The phototrophic microbial mat was harvested from Hot Lake, a hypersaline, epsomitic lake located near Oroville (Washington, USA). We operated two reactors: graphite electrodes were polarized at potentials of -700 mVAg/AgCl [cathodic (CAT) mat system] and +300 mVAg/AgCl [anodic (AN) mat system]more » and the electron transfer rates between the electrode and mat were monitored. We observed a diel cycle of electron transfer rates for both AN and CAT mat systems. Interestingly, the CAT mats generated the highest reducing current at the same time points that the AN mats showed the highest oxidizing current. To characterize the physicochemical factors influencing electron transfer processes, we measured depth profiles of dissolved oxygen (DO) and sulfide in the mats using microelectrodes. We further demonstrated that the mat-to-electrode and electrode-to-mat electron transfer rates were light- and temperature-dependent. Using nuclear magnetic resonance (NMR) imaging, we determined that the electrode potential regulated the diffusivity and porosity of the microbial mats. Both porosity and diffusivity were higher in the CAT mats than in the AN mats. We also used NMR spectroscopy for high-resolution quantitative metabolite analysis and found that the CAT mats had significantly higher concentrations of osmoprotectants such as betaine and trehalose. Subsequently, we performed amplicon sequencing across the V4 region of the 16S rRNA gene of incubated mats to understand the impact of electrode potential on microbial community structure. In conclusion, these data suggested that

  14. Microbial phototrophic fixation of atmospheric CO2 in China subtropical upland and paddy soils

    NASA Astrophysics Data System (ADS)

    Ge, Tida; Wu, Xiaohong; Chen, Xiaojuan; Yuan, Hongzhao; Zou, Ziying; Li, Baozhen; Zhou, Ping; Liu, Shoulong; Tong, Chengli; Brookes, Phil; Wu, Jinshui

    2013-07-01

    Autotrophic microorganisms, which can fix atmospheric CO2 to synthesize organic carbon, are numerous and widespread in soils. However, the extent and the mechanism of CO2 fixation in soils remain poorly understood. We incubated five upland and five paddy soils from subtropical China in an enclosed, continuously 14CO2-labeled, atmosphere and measured 14CO2 incorporated into soil organic matter (SOC14) and microbial biomass (MBC14) after 110 days. The five upland soils supported dominant crops soils (maize, wheat, sweet potato, and rapeseed) in the region, while all paddy soils were cultivated in a regime consisting of permanently-flooded double-cropping rice cultivation. The upland and paddy soils represented typical soil types (fluvisols and ultisols) and three landforms (upland, hill, and low mountain), ranging in total carbon from low (<10 g kg-1 soil organic carbon) to medium (10-20 g kg-1) to high (>20 g kg-1). Substantial amounts of 14CO2 were fixed into SOC14 (mean 20.1 ± 7.1 mg C kg-1 in upland soil, 121.1 ± 6.4 mg C kg-1 in paddy soil) in illuminated soils (12 h light/12 h dark), whereas no 14C was fixed in soils incubated in continuous darkness. We concluded that the microbial CO2 fixation was almost entirely phototrophic rather than chemotrophic. The rate of SOC14 synthesis was significantly higher in paddy soils than in upland soils. The SOC14 comprised means of 0.15 ± 0.01% (upland) and 0.65 ± 0.03% (paddy) of SOC. The extent of 14C immobilized as MBC14 and that present as dissolved organic C (DOC14) differed between soil types, accounting for 15.69-38.76% and 5.54-18.37% in upland soils and 15.57-40.03% and 3.67-7.17% of SOC14 in paddy soils, respectively. The MBC14/MBC and DOC14/DOC were 1.76-5.70% and 1.69-5.17% in the upland soils and 4.23-28.73% and 5.65-14.30% in the paddy soils, respectively. Thus, the newly-incorporated C stimulated the dynamics of DOC and MBC more than the dynamics of SOC. The SOC14 and MBC14 concentrations were highly

  15. Aerobic microbial enhanced oil recovery

    SciTech Connect

    Torsvik, T.; Gilje, E.; Sunde, E.

    1995-12-31

    In aerobic MEOR, the ability of oil-degrading bacteria to mobilize oil is used to increase oil recovery. In this process, oxygen and mineral nutrients are injected into the oil reservoir in order to stimulate growth of aerobic oil-degrading bacteria in the reservoir. Experiments carried out in a model sandstone with stock tank oil and bacteria isolated from offshore wells showed that residual oil saturation was lowered from 27% to 3%. The process was time dependent, not pore volume dependent. During MEOR flooding, the relative permeability of water was lowered. Oxygen and active bacteria were needed for the process to take place. Maximum efficiency was reached at low oxygen concentrations, approximately 1 mg O{sub 2}/liter.

  16. Low temperature treatment of domestic wastewater by purple phototrophic bacteria: Performance, activity, and community.

    PubMed

    Hülsen, Tim; Barry, Edward M; Lu, Yang; Puyol, Daniel; Batstone, Damien J

    2016-09-01

    Low wastewater temperatures affect microbial growth rates and microbial populations, as well as physical chemical characteristics of the wastewater. Wastewater treatment plant design needs to accommodate changing temperatures, and somewhat limited capacity is a key criticism of low strength anaerobic treatment such as Anaerobic Membrane Bioreactors (AnMBR). This study evaluates the applicability of an alternative platform utilizing purple phototrophic bacteria for low temperature domestic wastewater treatment. Two photo-anaerobic membrane bioreactors (PAnMBR) at ambient (22 °C) and low temperatures (10 °C) were compared to fully evaluate temperature response of critical processes. The results show good functionality at 10 °C in comparison with ambient operation. This enabled operation at 10 °C to discharge limits (TCOD < 100 mg L(-1); TN < 10 mg L(-1) and TP < 1 mg L(-1)) at a HRT < 1 d. While capacity of the system was not limited, microbial community showed a strong shift to a far narrower diversity, almost complete dominance by PPB, and of a single Rhodobacter spp. compared to a more diverse community in the ambient reactor. The outcomes of the current work enable applicability of PPB for domestic wastewater treatment to a broad range of regions. PMID:27235774

  17. Hydrologic Variability Affects Invertebrate Grazing on Phototrophic Biofilms in Stream Microcosms

    PubMed Central

    Ceola, Serena; Hödl, Iris; Adlboller, Martina; Singer, Gabriel; Bertuzzo, Enrico; Mari, Lorenzo; Botter, Gianluca; Waringer, Johann; Battin, Tom J.; Rinaldo, Andrea

    2013-01-01

    The temporal variability of streamflow is known to be a key feature structuring and controlling fluvial ecological communities and ecosystem processes. Although alterations of streamflow regime due to habitat fragmentation or other anthropogenic factors are ubiquitous, a quantitative understanding of their implications on ecosystem structure and function is far from complete. Here, by experimenting with two contrasting flow regimes in stream microcosms, we provide a novel mechanistic explanation for how fluctuating flow regimes may affect grazing of phototrophic biofilms (i.e., periphyton) by an invertebrate species (Ecdyonurus sp.). In both flow regimes light availability was manipulated as a control on autotroph biofilm productivity and grazer activity, thereby allowing the test of flow regime effects across various ratios of biofilm biomass to grazing activity. Average grazing rates were significantly enhanced under variable flow conditions and this effect was highest at intermediate light availability. Our results suggest that stochastic flow regimes, characterised by suitable fluctuations and temporal persistence, may offer increased windows of opportunity for grazing under favourable shear stress conditions. This bears important implications for the development of comprehensive schemes for water resources management and for the understanding of trophic carbon transfer in stream food webs. PMID:23613735

  18. Carbon isotope fractionation by thermophilic phototrophic sulfur bacteria: evidence for autotrophic growth in natural populations

    NASA Technical Reports Server (NTRS)

    Madigan, M. T.; Takigiku, R.; Lee, R. G.; Gest, H.; Hayes, J. M.

    1989-01-01

    Purple phototrophic bacteria of the genus Chromatium can grow as either photoautotrophs or photoheterotrophs. To determine the growth mode of the thermophilic Chromatium species, Chromatium tepidum, under in situ conditions, we have examined the carbon isotope fractionation patterns in laboratory cultures of this organism and in mats of C. tepidum which develop in sulfide thermal springs in Yellowstone National Park. Isotopic analysis (13C/12C) of total carbon, carotenoid pigments, and bacteriochlorophyll from photoautotrophically grown cultures of C. tepidum yielded 13C fractionation factors near -20%. Cells of C. tepidum grown on excess acetate, wherein synthesis of the Calvin cycle enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase ribulose bisphosphate carboxylase) was greatly repressed, were isotopically heavier, fractionation factors of ca. -7% being observed. Fractionation factors determined by isotopic analyses of cells and pigment fractions of natural populations of C. tepidum growing in three different sulfide thermal springs in Yellowstone National Park were approximately -20%, indicating that this purple sulfur bacterium grows as a photoautotroph in nature.

  19. Light-induced division and genomic synchrony in phototrophically growing cultures of Rhodopseudomonas sphaeroides.

    PubMed

    Lueking, D R; Campbell, T B; Burghardt, R C

    1981-05-01

    An experimental procedure for rapidly obtaining cell populations of phototrophically growing Rhodopseudomonas sphaeroides which display division and genomic synchrony has been developed. The basis of the procedure resides with the normal physiological response displayed by cells of R. sphaeroides that have been subjected to an immediate decrease in incident light intensity. After an abrupt high- to low-light transition of an asynchronously dividing cell population, an immediate cessation of increases in culture turbidity, total cell number, and net accumulations of culture deoxyribonucleic acid and phospholipid occurs. Total cell number remains constant for 2.5 h after the transition to low light, after which time, it undergoes a sharp increase. Reinitiation of high-light conditions of growth 1 h subsequent to this increase in total cell number results in a cell population possessing a high degree of division and genomic synchrony. A characterization of this procedure, together with a demonstration of its utility for studies on intracytoplasmic membrane assembly, is presented. PMID:7012139

  20. Diversity of extremophilic purple phototrophic bacteria in Soap Lake, a Central Washington (USA) Soda Lake.

    PubMed

    Asao, Marie; Pinkart, Holly C; Madigan, Michael T

    2011-08-01

    Culture-based and culture-independent methods were used to explore the diversity of phototrophic purple bacteria in Soap Lake, a small meromictic soda lake in the western USA. Among soda lakes, Soap Lake is unusual because it consists of distinct upper and lower water bodies of vastly different salinities, and its deep waters contain up to 175 mM sulfide. From Soap Lake water new alkaliphilic purple sulfur bacteria of the families Chromatiaceae and Ectothiorhodospiraceae were cultured, and one purple non-sulfur bacterium was isolated. Comparative sequence analysis of pufM, a gene that encodes a key photosynthetic reaction centre protein universally found in purple bacteria, was used to measure the diversity of purple bacteria in Soap Lake. Denaturing gradient gel electrophoresis and subsequent phylogenetic analyses of pufMs amplified from Soap Lake water revealed that a significant diversity of purple bacteria inhabit this soda lake. Although close relatives of several of the pufM phylotypes obtained from cultured species could also be detected in Soap Lake water, several other more divergent pufM phylotypes were also detected. It is possible that Soap Lake purple bacteria are major contributors of organic matter into the ecosystem of this lake, especially in its extensive anoxic and sulfidic deep waters. PMID:21410624

  1. Cenoses of phototrophic algae of ultrasaline lakes in the Kulunda steppe (Altai krai, Russian Federation)

    NASA Astrophysics Data System (ADS)

    Sapozhnikov, Ph. V.; Kalinina, O. Yu.; Nikitin, M. A.; Samylina, O. S.

    2016-01-01

    In 2012, expeditions of the Institute of Microbiology, Russian Academy of Sciences, delivered samples of algo-bacterial mats from Kulunda steppe alkaline lakes (Petukhovskoe alkaline lake, Tanatar VI, and Gorchina III). The filamentous alga Ctenocladus circinnatus (Chlorophyta) acted as an edificator of the mats. The composition of cenoses algocomponents also included chlorophytes Dunaliella viridis and Picocystis salinarum as well as diatoms Anomeoneis sphaerophora, Brachysira brebissonii, B. zellensis, Mastogloia pusilla var. subcapitata, Nitzschia amphibia, N. cf. communis, and Nitzschia sp. 1. The composition and structure of phototrophic algae cenoses (including diatom taxocenes) were described for the investigated lakes for the first time. For the period from 2011 to 2012, the total mineralization significantly increased in lakes. This involved sensible alterations of cenoses. B. zellensis was the most permanent component of diatom taxocenes in both seasons. In the summer of 2011, it was often accompanied by A. sphaerophora and B. brebissonii. In the summer of 2012, A. sphaerophora was found only singularly in Lake Gorchina III, and some biotopes of Lake Tanatar VI were massively inhabited by N. cf. communis, including colonies that had not been previously described for the species. The genetic analysis of three diatoms, which are markedly different from each other in their appearance and were sampled from different lakes but were all determined as Nitzschia cf. communis, showed their complete similarity to each other with the 18S rRNA gene fragment and the highest similarity of all the three diatoms with the species Nitzschia communis.

  2. The Organellar Genomes of Chromera and Vitrella, the Phototrophic Relatives of Apicomplexan Parasites.

    PubMed

    Oborník, Miroslav; Lukeš, Julius

    2015-01-01

    Apicomplexa are known to contain greatly reduced organellar genomes. Their mitochondrial genome carries only three protein-coding genes, and their plastid genome is reduced to a 35-kb-long circle. The discovery of coral-endosymbiotic algae Chromera velia and Vitrella brassicaformis, which share a common ancestry with Apicomplexa, provided an opportunity to study possibly ancestral forms of organellar genomes, a unique glimpse into the evolutionary history of apicomplexan parasites. The structurally similar mitochondrial genomes of Chromera and Vitrella differ in gene content, which is reflected in the composition of their respiratory chains. Thus, Chromera lacks respiratory complexes I and III, whereas Vitrella and apicomplexan parasites are missing only complex I. Plastid genomes differ substantially between these algae, particularly in structure: The Chromera plastid genome is a linear, 120-kb molecule with large and divergent genes, whereas the plastid genome of Vitrella is a highly compact circle that is only 85 kb long but nonetheless contains more genes than that of Chromera. It appears that organellar genomes have already been reduced in free-living phototrophic ancestors of apicomplexan parasites, and such reduction is not associated with parasitism. PMID:26092225

  3. Phototrophic periphyton techniques combine phosphorous removal and recovery for sustainable salt-soil zone.

    PubMed

    Lu, Haiying; Feng, Yanfang; Wu, Yonghong; Yang, Linzhang; Shao, Hongbo

    2016-10-15

    The P (Pi as KH2PO4 and Po as ATP) removal processes by phototrophic periphyton were investigated by determining the removal kinetics, metal content (Ca, Mg, Al, Fe, Cu, and Zn) of the solution and P fractions (Labile-P, Fe/Al-P, Ca-P, and Res-P) within the periphyton. Results showed that the periphyton was able to remove completely both Pi and Po after 48h when periphyton content was greater than 0.2gL(-1) (dry weight). The difference between Pi and Po removal was the conversion of Po into Pi by the periphyton, after that the removal mechanism was similar. The P removal mechanism was mainly due to the adsorption on the surfaces of the periphyton, including two aspects: i) the adsorption of PO4(3-) onto metal salts such as calcium carbonate (~50%) and ii) complexation between PO4(3-) and metal cations such as Ca(2+) (~40%). However, this bio-adsorptional process was significantly influenced by the extracellular polymeric substance (EPS) of periphyton, water hardness, initial P concentration, temperature and light intensity. This study not only deepens the understanding of P biogeochemical process in aquatic ecosystem, but provides a potential biomaterial for combining phosphorous removal and recovery from non-point source wastewaters, especially around salt-soil zone. PMID:27328877

  4. Development of Synechocystis sp. PCC 6803 as a Phototrophic Cell Factory

    PubMed Central

    Yu, Yi; You, Le; Liu, Dianyi; Hollinshead, Whitney; Tang, Yinjie J.; Zhang, Fuzhong

    2013-01-01

    Cyanobacteria (blue-green algae) play profound roles in ecology and biogeochemistry. One model cyanobacterial species is the unicellular cyanobacterium Synechocystis sp. PCC 6803. This species is highly amenable to genetic modification. Its genome has been sequenced and many systems biology and molecular biology tools are available to study this bacterium. Recently, researchers have put significant efforts into understanding and engineering this bacterium to produce chemicals and biofuels from sunlight and CO2. To demonstrate our perspective on the application of this cyanobacterium as a photosynthesis-based chassis, we summarize the recent research on Synechocystis 6803 by focusing on five topics: rate-limiting factors for cell cultivation; molecular tools for genetic modifications; high-throughput system biology for genome wide analysis; metabolic modeling for physiological prediction and rational metabolic engineering; and applications in producing diverse chemicals. We also discuss the particular challenges for systems analysis and engineering applications of this microorganism, including precise characterization of versatile cell metabolism, improvement of product rates and titers, bioprocess scale-up, and product recovery. Although much progress has been achieved in the development of Synechocystis 6803 as a phototrophic cell factory, the biotechnology for “Compounds from Synechocystis” is still significantly lagging behind those for heterotrophic microbes (e.g., Escherichia coli). PMID:23945601

  5. Carbon isotope fractionation by thermophilic phototrophic sulfur bacteria: evidence for autotrophic growth in natural populations.

    PubMed Central

    Madigan, M T; Takigiku, R; Lee, R G; Gest, H; Hayes, J M

    1989-01-01

    Purple phototrophic bacteria of the genus Chromatium can grow as either photoautotrophs or photoheterotrophs. To determine the growth mode of the thermophilic Chromatium species, Chromatium tepidum, under in situ conditions, we have examined the carbon isotope fractionation patterns in laboratory cultures of this organism and in mats of C. tepidum which develop in sulfide thermal springs in Yellowstone National Park. Isotopic analysis (13C/12C) of total carbon, carotenoid pigments, and bacteriochlorophyll from photoautotrophically grown cultures of C. tepidum yielded 13C fractionation factors near -20%. Cells of C. tepidum grown on excess acetate, wherein synthesis of the Calvin cycle enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase ribulose bisphosphate carboxylase) was greatly repressed, were isotopically heavier, fractionation factors of ca. -7% being observed. Fractionation factors determined by isotopic analyses of cells and pigment fractions of natural populations of C. tepidum growing in three different sulfide thermal springs in Yellowstone National Park were approximately -20%, indicating that this purple sulfur bacterium grows as a photoautotroph in nature. PMID:11536609

  6. WWOX loss activates aerobic glycolysis

    PubMed Central

    Abu-Remaileh, Muhannad; Seewaldt, Victoria L; Aqeilan, Rami I

    2015-01-01

    Cancer cells undergo reprogramming of glucose metabolism to limit energy production to glycolysis—a state known as “aerobic glycolysis.” Hypoxia-inducible factor 1 (HIF1α) is a transcription factor that regulates many genes responsible for this switch. As discussed here, new data suggest that the tumor suppressor WW domain-containing oxidoreductase (WWOX) modulates HIF1α, thereby regulating this metabolic state. PMID:27308416

  7. The Draft Genome Sequence of Sphingomonas sp. Strain FukuSWIS1, Obtained from Acidic Lake Grosse Fuchskuhle, Indicates Photoheterotrophy and a Potential for Humic Matter Degradation

    PubMed Central

    Salka, Ivette; Srivastava, Abhishek; Allgaier, Martin

    2014-01-01

    Sphingomonas spp. are Alphaproteobacteria considered to be versatile bacteria that can utilize a variety of natural substrates available in terrestrial and aquatic systems. Sphingomonas sp. strain FukuSWIS1 was isolated from the eutrophic and acidic freshwater Lake Grosse Fuchskuhle in northeastern Germany. The strain has a genome size of 3.89 Mb, possesses a set of photosynthetic genes, and expresses photopigment BChl a under oxic conditions. Thus, this strain belongs to the aerobic anoxygenic phototrophic (AAP) bacteria, which are most likely involved in humic matter degradation as indicated by the presence of organic compound mineralizing genes. PMID:25395647

  8. Methods to determine aerobic endurance.

    PubMed

    Bosquet, Laurent; Léger, Luc; Legros, Patrick

    2002-01-01

    Physiological testing of elite athletes requires the correct identification and assessment of sports-specific underlying factors. It is now recognised that performance in long-distance events is determined by maximal oxygen uptake (V(2 max)), energy cost of exercise and the maximal fractional utilisation of V(2 max) in any realised performance or as a corollary a set percentage of V(2 max) that could be endured as long as possible. This later ability is defined as endurance, and more precisely aerobic endurance, since V(2 max) sets the upper limit of aerobic pathway. It should be distinguished from endurance ability or endurance performance, which are synonymous with performance in long-distance events. The present review examines methods available in the literature to assess aerobic endurance. They are numerous and can be classified into two categories, namely direct and indirect methods. Direct methods bring together all indices that allow either a complete or a partial representation of the power-duration relationship, while indirect methods revolve around the determination of the so-called anaerobic threshold (AT). With regard to direct methods, performance in a series of tests provides a more complete and presumably more valid description of the power-duration relationship than performance in a single test, even if both approaches are well correlated with each other. However, the question remains open to determine which systems model should be employed among the several available in the literature, and how to use them in the prescription of training intensities. As for indirect methods, there is quantitative accumulation of data supporting the utilisation of the AT to assess aerobic endurance and to prescribe training intensities. However, it appears that: there is no unique intensity corresponding to the AT, since criteria available in the literature provide inconsistent results; and the non-invasive determination of the AT using ventilatory and heart rate

  9. Aerobic granular processes: Current research trends.

    PubMed

    Zhang, Quanguo; Hu, Jianjun; Lee, Duu-Jong

    2016-06-01

    Aerobic granules are large biological aggregates with compact interiors that can be used in efficient wastewater treatment. This mini-review presents new researches on the development of aerobic granular processes, extended treatments for complicated pollutants, granulation mechanisms and enhancements of granule stability in long-term operation or storage, and the reuse of waste biomass as renewable resources. A discussion on the challenges of, and prospects for, the commercialization of aerobic granular process is provided. PMID:26873285

  10. Domestic wastewater treatment with purple phototrophic bacteria using a novel continuous photo anaerobic membrane bioreactor.

    PubMed

    Hülsen, Tim; Barry, Edward M; Lu, Yang; Puyol, Daniel; Keller, Jürg; Batstone, Damien J

    2016-09-01

    A key future challenge of domestic wastewater treatment is nutrient recovery while still achieving acceptable discharge limits. Nutrient partitioning using purple phototrophic bacteria (PPB) has the potential to biologically concentrate nutrients through growth. This study evaluates the use of PPB in a continuous photo-anaerobic membrane bioreactor (PAnMBR) for simultaneous organics and nutrient removal from domestic wastewater. This process could continuously treat domestic wastewater to discharge limits (<50 mgCOD L(-1), 5 mgN L(-1), 1.0 mgP L(-1)). Approximately 6.4 ± 1.3 gNH4-N and 1.1 ± 0.2 gPO4-P for every 100 gSCOD were removed at a hydraulic retention time of 8-24 h and volumetric loading rates of 0.8-2.5 COD kg m(3) d(-1). Thus, a minimum of 200 mg L(-1) of ethanol (to provide soluble COD) was required to achieve these discharge limits. Microbial community through sequencing indicated dominance of >60% of PPB, though the PPB community was highly variable. The outcomes from the current work demonstrate the potential of PPB for continuous domestic (and possibly industrial) wastewater treatment and nutrient recovery. Technical challenges include the in situ COD supply in a continuous reactor system, as well as efficient light delivery. Addition of external (agricultural or fossil) derived organics is not financially nor environmentally justified, and carbon needs to be sourced internally from the biomass itself to enable this technology. Reduced energy consumption for lighting is technically feasible, and needs to be addressed as a key objective in scaleup. PMID:27232993

  11. Genomic analysis reveals key aspects of prokaryotic symbiosis in the phototrophic consortium “Chlorochromatium aggregatum”

    PubMed Central

    2013-01-01

    Background ‘Chlorochromatium aggregatum’ is a phototrophic consortium, a symbiosis that may represent the highest degree of mutual interdependence between two unrelated bacteria not associated with a eukaryotic host. ‘Chlorochromatium aggregatum’ is a motile, barrel-shaped aggregate formed from a single cell of ‘Candidatus Symbiobacter mobilis”, a polarly flagellated, non-pigmented, heterotrophic bacterium, which is surrounded by approximately 15 epibiont cells of Chlorobium chlorochromatii, a non-motile photolithoautotrophic green sulfur bacterium. Results We analyzed the complete genome sequences of both organisms to understand the basis for this symbiosis. Chl. chlorochromatii has acquired relatively few symbiosis-specific genes; most acquired genes are predicted to modify the cell wall or function in cell-cell adhesion. In striking contrast, ‘Ca. S. mobilis’ appears to have undergone massive gene loss, is probably no longer capable of independent growth, and thus may only reproduce when consortia divide. A detailed model for the energetic and metabolic bases of the dependency of ‘Ca. S. mobilis’ on Chl. chlorochromatii is described. Conclusions Genomic analyses suggest that three types of interactions lead to a highly sophisticated relationship between these two organisms. Firstly, extensive metabolic exchange, involving carbon, nitrogen, and sulfur sources as well as vitamins, occurs from the epibiont to the central bacterium. Secondly, ‘Ca. S. mobilis’ can sense and move towards light and sulfide, resources that only directly benefit the epibiont. Thirdly, electron cycling mechanisms, particularly those mediated by quinones and potentially involving shared protonmotive force, could provide an important basis for energy exchange in this and other symbiotic relationships. PMID:24267588

  12. Mineral and non-carbon nutrient utilization and recovery during sequential phototrophic-heterotrophic growth of lipid-rich algae.

    PubMed

    Bohutskyi, Pavlo; Liu, Kexin; Kessler, Ben A; Kula, Thomas; Hong, Yongseok; Bouwer, Edward J; Betenbaugh, Michael J; Allnutt, F C Thomas

    2014-06-01

    A critical factor in implementing microalgal biofuels for mass production is the nutrient requirements. The current study investigated the fate of macro- and micronutrients and their availability in a sequential phototrophic-heterotrophic production process for the lipid rich microalga Auxenochlorella protothecoides. More than 99 % (by weight) of overall process nutrients were supplied during the initial photoautotrophic stage reflecting its significantly larger volume. Under photoautotrophic growth conditions only 9-35 % of supplied Mn, S, Fe, N, Mg, and Cu and less than 5 % of P, Mo, Co, B, Zn, and Ca were consumed by the algae. The rest of these nutrients remain in the spent growth media during the culture concentration-down from an 800 L phototrophic pond to a 5 L heterotrophic fermenter. In contrast, Zn, Mo, Mn, Mg, Ca, and N were exhausted (90-99 % removal) during the first 25 h of the heterotrophic growth stage. The depletion of these key nutrients may have ultimately limited the final biomass density and/or lipid productivity achieved. Approximately 10-20 % of the total supplied S, Mn, Fe, N, and Cu and 5 % of Ca and Zn were assimilated into algal biomass. Several elements including N, P, Mn, B, Cu, Ca, Mg, S, and Fe were released back into the liquid phase by anaerobic digestion (AD) of the residual biomass after lipid extraction. The nutrients recovered from the AD effluent and remaining in the spent medium should be recycled or their initial concentration to the phototrophic stage decreased to enhance process economics and sustainability for future commercialization of algal-derived biofuels. PMID:24839256

  13. Analysis of a marine phototrophic biofilm by confocal laser scanning microscopy using the new image quantification software PHLIP

    PubMed Central

    Mueller, Lukas N; de Brouwer, Jody FC; Almeida, Jonas S; Stal, Lucas J; Xavier, João B

    2006-01-01

    Background Confocal laser scanning microscopy (CLSM) is the method of choice to study interfacial biofilms and acquires time-resolved three-dimensional data of the biofilm structure. CLSM can be used in a multi-channel modus where the different channels map individual biofilm components. This communication presents a novel image quantification tool, PHLIP, for the quantitative analysis of large amounts of multichannel CLSM data in an automated way. PHLIP can be freely downloaded from Results PHLIP is an open source public license Matlab toolbox that includes functions for CLSM imaging data handling and ten image analysis operations describing various aspects of biofilm morphology. The use of PHLIP is here demonstrated by a study of the development of a natural marine phototrophic biofilm. It is shown how the examination of the individual biofilm components using the multi-channel capability of PHLIP allowed the description of the dynamic spatial and temporal separation of diatoms, bacteria and organic and inorganic matter during the shift from a bacteria-dominated to a diatom-dominated phototrophic biofilm. Reflection images and weight measurements complementing the PHLIP analyses suggest that a large part of the biofilm mass consisted of inorganic mineral material. Conclusion The presented case study reveals new insight into the temporal development of a phototrophic biofilm where multi-channel imaging allowed to parallel monitor the dynamics of the individual biofilm components over time. This application of PHLIP presents the power of biofilm image analysis by multi-channel CLSM software and demonstrates the importance of PHLIP for the scientific community as a flexible and extendable image analysis platform for automated image processing. PMID:16412253

  14. Diversity of an aerial phototrophic coating of historic buildings in the former Auschwitz II-Birkenau concentration camp.

    PubMed

    Nowicka-Krawczyk, Paulina; Żelazna-Wieczorek, Joanna; Otlewska, Anna; Koziróg, Anna; Rajkowska, Katarzyna; Piotrowska, Małgorzata; Gutarowska, Beata; Żydzik-Białek, Agnieszka

    2014-09-15

    Aerial phototrophs colonize materials of anthropogenic origin, thus contributing to their biodeterioration. Structures preserved at the former Auschwitz II-Birkenau concentration and extermination camp show signs of degradation by cyanobacteria and algae. In order to protect the Auschwitz-Birkenau Memorial Site, diversity of aerial phototrophs growing on the historic buildings has been studied. Analyses of cyanobacterial and algal biofilms growing on various construction substrates were carried out in summer and winter. Multivariate data analyses were used to: characterize the diversity of cyanobacteria and algae growing in brick and wooden camp buildings depending on the research season, indicate preferences of cyanobacteria and algae in colonizing substrates, and to predict the environmental factor that most determines the growth of phototrophs. The biofilms were formed mainly by cyanobacteria, green algae and diatoms. The amount of cyanobacteria and algae in the biofilms was varied, which resulted from changes in climatic conditions, the type of substrate and the height at which the biofilms developed. In the summer, the ratio of cyanobacteria and algae groups was balanced, while in the winter, green algae and diatoms were dominant. Green algae showed a preference for colonizing plaster, wood and concrete, of which the walls and doors of the buildings were made. Their participation was correlated with a height gradient. Cyanobacteria and diatoms grew on bricks and soil on the floor of the buildings and temperature and relative humidity were the factors that modified their amount. Green algae were more cosmopolitan-occurred in dry places, potentially inaccessible to other organisms; therefore, they have been identified as the pioneer group in the prevailing climatic conditions. PMID:24937497

  15. Heterotrophic symbionts of phototrophic consortia: members of a novel diverse cluster of Betaproteobacteria characterized by a tandem rrn operon structure.

    PubMed

    Pfannes, Kristina R; Vogl, Kajetan; Overmann, Jörg

    2007-11-01

    Phototrophic consortia represent the most highly developed type of interspecific association of bacteria and consist of green sulfur bacterial epibionts attached around a central colourless rod-shaped bacterium. Based on 16S rRNA gene sequencing, the central bacterium of the consortium 'Chlorochromatium aggregatum' was recently shown to represent a novel and phylogenetically isolated lineage of the Comamonadaceae within the beta-subgroup of the Proteobacteria. To date, 19 types of phototrophic consortia are distinguished based on the different 16S rRNA gene sequences of their epibionts, but the diversity and phylogenetic relationships of the heterotrophic partner bacteria are still unknown. We developed an approach based on the specific rrn (ribosomal RNA) operon structure of the central bacterium of 'C. aggregatum' to recover 16S rRNA gene sequences of other central bacteria and their close relatives from natural consortia populations. Genomic DNA of the central bacterium of 'C. aggregatum' was first enriched several hundred-fold by employing a selective method for growth of consortia in a monolayer biofilm followed by a purification of the genome of the central bacterium by cesium chloride-bisbenzimidazole equilibrium density gradient centrifugation. A combination of inverse PCR, cloning and sequencing revealed that two rrn operons of the central bacterium are arranged in a tandem fashion and are separated by an unusually short intergenic region of 195 base pairs. This rare gene order was exploited to screen various natural microbial communities by PCR. We discovered a diverse and previously unknown subgroup of Betaproteobacteria in the chemoclines of freshwater lakes. This group was absent in other freshwater and soil samples. All the 16S rRNA gene sequences recovered are related to that of the central bacterium of 'C. aggregatum'. Fluorescence in situ hybridization indicated that two of these sequences originated from central bacteria of different phototrophic

  16. Aerobic Fitness for the Moderately Retarded.

    ERIC Educational Resources Information Center

    Bauer, Dan

    1981-01-01

    Intended for physical education teachers, the booklet offers ideas for incorporating aerobic conditioning into programs for moderately mentally retarded students. An explanation of aerobic fitness and its benefits is followed by information on initiating a fitness program with evaluation of height, weight, body fat, resting heart rate, and…

  17. Aerobic rice mechanization: techniques for crop establishment

    NASA Astrophysics Data System (ADS)

    Khusairy, K. M.; Ayob, H.; Chan, C. S.; Fauzi, M. I. Mohamed; Mohamad Fakhrul, Z. O.; Shahril Shah, G. S. M.; Azlan, O.; Rasad, M. A.; Hashim, A. M.; Arshad, Z.; E, E. Ibrahim; Saifulizan, M. N.

    2015-12-01

    Rice being the staple food crops, hundreds of land races in it makes the diversity of rice crops. Aerobic rice production was introduced which requires much less water input to safeguard and sustain the rice production and conserve water due to decreasing water resources, climatic changes and competition from urban and industrial users. Mechanization system plays an important role for the success of aerobic rice cultivation. All farming activities for aerobic rice production are run on aerobic soil conditions. Row seeder mechanization system is developed to replace conventional seeding technique on the aerobic rice field. It is targeted for small and the large scale aerobic rice farmers. The aero - seeder machine is used for the small scale aerobic rice field, while the accord - seeder is used for the large scale aerobic rice field. The use of this mechanization machine can eliminate the tedious and inaccurate seeding operations reduce labour costs and increases work rate. The machine is easy to operate and it can increase crop establishment rate. It reduce missing hill, increasing planting and crop with high yield can be produce. This machine is designed for low costs maintenance and it is easy to dismantle and assemble during maintenance and it is safe to be used.

  18. Skeletal Muscle Hypertrophy after Aerobic Exercise Training

    PubMed Central

    Konopka, Adam R.; Harber, Matthew P.

    2014-01-01

    Current dogma suggests aerobic exercise training has minimal effect on skeletal muscle size. We and others have demonstrated that aerobic exercise acutely and chronically alters protein metabolism and induces skeletal muscle hypertrophy. These findings promote an antithesis to the status quo by providing novel perspective on skeletal muscle mass regulation and insight into exercise-countermeasures for populations prone to muscle loss. PMID:24508740

  19. Aerobic Dancing--A Rhythmic Sport.

    ERIC Educational Resources Information Center

    Sorensen, Jacki

    Fitness programs now and in the future must offer built-in cardiovascular conditioning, variety, novelty, and change to meet the physical, mental, and emotional needs of our society. Aerobic dancing (dancing designed to train and strengthen the heart, lungs, and vascular system) is one of the first indoor group Aerobic exercise programs designed…

  20. Exposure of phototrophs to 548 days in low Earth orbit: microbial selection pressures in outer space and on early earth.

    PubMed

    Cockell, Charles S; Rettberg, Petra; Rabbow, Elke; Olsson-Francis, Karen

    2011-10-01

    An epilithic microbial community was launched into low Earth orbit, and exposed to conditions in outer space for 548 days on the European Space Agency EXPOSE-E facility outside the International Space Station. The natural phototroph biofilm was augmented with akinetes of Anabaena cylindrica and vegetative cells of Nostoc commune and Chroococcidiopsis. In space-exposed dark controls, two algae (Chlorella and Rosenvingiella spp.), a cyanobacterium (Gloeocapsa sp.) and two bacteria associated with the natural community survived. Of the augmented organisms, cells of A. cylindrica and Chroococcidiopsis survived, but no cells of N. commune. Only cells of Chroococcidiopsis were cultured from samples exposed to the unattenuated extraterrestrial ultraviolet (UV) spectrum (>110 nm or 200 nm). Raman spectroscopy and bright-field microscopy showed that under these conditions the surface cells were bleached and their carotenoids were destroyed, although cell morphology was preserved. These experiments demonstrate that outer space can act as a selection pressure on the composition of microbial communities. The results obtained from samples exposed to >200 nm UV (simulating the putative worst-case UV exposure on the early Earth) demonstrate the potential for epilithic colonization of land masses during that time, but that UV radiation on anoxic planets can act as a strong selection pressure on surface-dwelling organisms. Finally, these experiments have yielded new phototrophic organisms of potential use in biomass and oxygen production in space exploration. PMID:21593797

  1. Phototrophic Biofilm Assembly in Microbial-Mat-Derived Unicyanobacterial Consortia: Model Systems for the Study of Autotroph-Heterotroph Interactions

    SciTech Connect

    Cole, Jessica K.; Hutchison, Janine R.; Renslow, Ryan S.; Kim, Young-Mo; Chrisler, William B.; Engelmann, Heather E.; Dohnalkova, Alice; Hu, Dehong; Metz, Thomas O.; Fredrickson, Jim K.; Lindemann, Stephen R.

    2014-04-07

    Though microbial autotroph-heterotroph interactions influence biogeochemical cycles on a global scale, the diversity and complexity of natural systems and their intractability to in situ environmental manipulation makes elucidation of the principles governing these interactions challenging. Examination of primary succession during phototrophic biofilm assembly provides a robust means by which to elucidate the dynamics of such interactions and determine their influence upon recruitment and maintenance of phylogenetic and functional diversity in microbial communities. We isolated and characterized two unicyanobacterial consortia from the Hot Lake phototrophic mat, quantifying the structural and community composition of their assembling biofilms. The same heterotrophs were retained in both consortia and included members of Alphaproteobacteria, Gammaproteobacteria, and Bacteroidetes, taxa frequently reported as consorts of microbial photoautotrophs. Cyanobacteria led biofilm assembly, eventually giving way to a late heterotrophic bloom. The consortial biofilms exhibited similar patterns of assembly, with the relative abundances of members of Bacteroidetes and Alphaproteobacteria increasing and members of Gammaproteobacteria decreasing as colonization progressed. Despite similar trends in assembly at higher taxa, the consortia exhibited substantial differences in community structure at the species level. These similar patterns of assembly with divergent community structures suggest that, while similar niches are created by the metabolism of the cyanobacteria, the resultant webs of autotroph-heterotroph and heterotroph-heterotroph interactions driving metabolic exchange are specific to each primary producer. Altogether, our data support these Hot Lake unicyanobacterial consortia as generalizable model systems whose simplicity and tractability permit the deciphering of community assembly principles relevant to natural microbial communities.

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

    PubMed

    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. PMID:26635736

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

    PubMed Central

    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. PMID:26635736

  4. Carotenoid and fatty acid compositions of an indigenous Ettlia texensis isolate (Chlorophyceae) under phototrophic and mixotrophic conditions.

    PubMed

    Yıldırım, Arzu; Demirel, Zeliha; İşleten-Hoşoğlu, Müge; Akgün, İsmail Hakkı; Hatipoğlu-Uslu, Sevde; Conk-Dalay, Meltem

    2014-02-01

    Ettlia oleoabundance (formerly known as Neochloris oleoabundance) is an attractive candidate for biodiesel production because of its high lipid accumulation, and it's taking the majority of the attention among the strains of Ettlia genus; however, potential of the other genus members is unknown. An indigenous strain from Salda Lake (South West Turkey) identified by 18S rDNA sequencing as Ettlia texensis (GenBank accession no: JQ038221), and its fatty acid and carotenoid compositions under phototrophic and mixotrophic conditions was investigated to evaluate the potential of the strain for commercial uses. A threefold increase was observed in total lipid content (total fatty acids; from 13% to 37%) in mixotrophic culture respect to the phototrophic growth conditions. The oleic acid (C18:1) and alpha-linolenic acid (18:3) were the major unsaturated fatty acids accounting for 40% and 13.2% of total fatty acids in mixotrophic culture, respectively. Carotenoid analyses of the mixotrophic culture revealed the metabolite canthaxanthin, a commercially valuable carotenoid used mainly for food coloring, was the major constituent among other pigments. The possible use of E. texensis in biotechnological applications is discussed. PMID:24166102

  5. Exposure of phototrophs to 548 days in low Earth orbit: microbial selection pressures in outer space and on early earth

    PubMed Central

    Cockell, Charles S; Rettberg, Petra; Rabbow, Elke; Olsson-Francis, Karen

    2011-01-01

    An epilithic microbial community was launched into low Earth orbit, and exposed to conditions in outer space for 548 days on the European Space Agency EXPOSE-E facility outside the International Space Station. The natural phototroph biofilm was augmented with akinetes of Anabaena cylindrica and vegetative cells of Nostoc commune and Chroococcidiopsis. In space-exposed dark controls, two algae (Chlorella and Rosenvingiella spp.), a cyanobacterium (Gloeocapsa sp.) and two bacteria associated with the natural community survived. Of the augmented organisms, cells of A. cylindrica and Chroococcidiopsis survived, but no cells of N. commune. Only cells of Chroococcidiopsis were cultured from samples exposed to the unattenuated extraterrestrial ultraviolet (UV) spectrum (>110 nm or 200 nm). Raman spectroscopy and bright-field microscopy showed that under these conditions the surface cells were bleached and their carotenoids were destroyed, although cell morphology was preserved. These experiments demonstrate that outer space can act as a selection pressure on the composition of microbial communities. The results obtained from samples exposed to >200 nm UV (simulating the putative worst-case UV exposure on the early Earth) demonstrate the potential for epilithic colonization of land masses during that time, but that UV radiation on anoxic planets can act as a strong selection pressure on surface-dwelling organisms. Finally, these experiments have yielded new phototrophic organisms of potential use in biomass and oxygen production in space exploration. PMID:21593797

  6. Green synthesis of biogenic metal nanoparticles by terrestrial and aquatic phototrophic and heterotrophic eukaryotes and biocompatible agents.

    PubMed

    Narayanan, Kannan Badri; Sakthivel, Natarajan

    2011-12-12

    The size, shape and controlled dispersity of nanoparticles play a vital role in determining the physical, chemical, optical and electronic properties attributing its applications in environmental, biotechnological and biomedical fields. Various physical and chemical processes have been exploited in the synthesis of several inorganic metal nanoparticles by wet and dry approaches viz., ultraviolet irradiation, aerosol technologies, lithography, laser ablation, ultrasonic fields, and photochemical reduction techniques. However, these methodologies remain expensive and involve the use of hazardous chemicals. Therefore, there is a growing concern for the development of alternative environment friendly and sustainable methods. Increasing awareness towards green chemistry and biological processes has led to a necessity to develop simple, cost-effective and eco-friendly procedures. Phototrophic eukaryotes such as plants, algae, and diatoms and heterotrophic human cell lines and some biocompatible agents have been reported to synthesize greener nanoparticles like cobalt, copper, silver, gold, bimetallic alloys, silica, palladium, platinum, iridium, magnetite and quantum dots. Owing to the diversity and sustainability, the use of phototrophic and heterotrophic eukaryotes and biocompatible agents for the synthesis of nanomaterials is yet to be fully explored. This review describes the recent advancements in the green synthesis and applications of metal nanoparticles by plants, aquatic autotrophs, human cell lines, biocompatible agents and biomolecules. PMID:21981929

  7. Spatially-resolved carbon flow through a hypersaline phototrophic microbial mat

    NASA Astrophysics Data System (ADS)

    Moran, J.; Lindemann, S. R.; Cory, A. B.; Courtney, S.; Cole, J. K.; Fredrickson, J.

    2013-12-01

    Hot Lake is a hypersaline, meromictic lake located in an endorheic basin in north-central Washington. Low annual rainfall and high evaporation rates contribute to the lake's high salinity. The predominant dissolved salt is magnesium sulfate, of which monimolimnion waters may seasonally exceed 2 M concentrations. Induced by its high salinity and meromictic nature, Hot Lake displays an inverse thermal gradient with deep horizons seasonally exceeding 50 °C. Despite extreme conditions, dense benthic microbial mats composed of cyanobacteria, anoxygenic photoheterotrophs, and bacterial heterotroph populations develop in the lake. These mats can exceed 1 cm in thickness and display vertical stratification in color due to bacterial pigmentation. Typical mat stratification includes an orange surface layer underlain by green and purple layers at increasing depth. Carbonates, including aragonite and magnesite, are observed within the mat and their formation is likely induced or influenced by microbial metabolic activities and associated pH excursions. We are exploring the role Hot Lake's microbial mats play in carbon cycling. Cyanobacteria are the dominant CO2-fixing organisms in the mat and we seek to understand the spatial and metabolic controls on how the carbon initially fixed by mat cyanobacteria is transferred to associated heterotrophic populations spread throughout the mat strata. Secondly, we seek to understand the overall net carbon balance of the mat through a growing season. We are using a stable isotope probing approach for assessing carbon uptake and migration through representative mat samples. We performed a series of ex situ incubations of freshly harvested mat samples in lake water amended with 13C-labeled bicarbonate or substrates commonly consumed by heterotrophs (including acetate and glucose) and using multiple stable isotope techniques to track label uptake, residence time, remineralization, and location within the mat. In addition to bulk isotope

  8. Phaeobacterium nitratireducens gen. nov., sp. nov., a phototrophic gammaproteobacterium isolated from a mangrove forest sediment sample.

    PubMed

    Nupur; Tanuku, Naga Radha Srinivas; Shinichi, Takaichi; Pinnaka, Anil Kumar

    2015-08-01

    A novel brown-coloured, Gram-negative-staining, rod-shaped, motile, phototrophic, purple sulfur bacterium, designated strain AK40T, was isolated in pure culture from a sediment sample collected from Coringa mangrove forest, India. Strain AK40T contained bacteriochlorophyll a and carotenoids of the rhodopin series as major photosynthetic pigments. Strain AK40T was able to grow photoheterotrophically and could utilize a number of organic substrates. It was unable to grow photoautotrophically and did not utilize sulfide or thiosulfate as electron donors. Thiamine and riboflavin were required for growth. The dominant fatty acids were C12 : 0, C16 : 0, C18 : 1ω7c and summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH). The polar lipid profile of strain AK40T was found to contain diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and eight unidentified lipids. Q-10 was the predominant respiratory quinone. The DNA G+C content of strain AK40T was 65.5 mol%. 16S rRNA gene sequence comparisons indicated that the isolate represented a member of the family Chromatiaceae within the class Gammaproteobacteria. 16S rRNA gene sequence analysis indicated that strain AK40T was closely related to Phaeochromatium fluminis, with 95.2% pairwise sequence similarity to the type strain; sequence similarity to strains of other species of the family was 90.8-94.8%. Based on the sequence comparison data, strain AK40T was positioned distinctly outside the group formed by the genera Phaeochromatium, Marichromatium, Halochromatium, Thiohalocapsa, Rhabdochromatium and Thiorhodovibrio. Distinct morphological, physiological and genotypic differences from previously described taxa supported the classification of this isolate as a representative of a novel species in a new genus, for which the name Phaeobacterium nitratireducens gen. nov., sp. nov. is proposed. The type strain of Phaeobacterium nitratireducens is AK40T ( = JCM 19219T = MTCC 11824T

  9. Fit women are not able to use the whole aerobic capacity during aerobic dance.

    PubMed

    Edvardsen, Elisabeth; Ingjer, Frank; Bø, Kari

    2011-12-01

    Edvardsen, E, Ingjer, F, and Bø, K. Fit women are not able to use the whole aerobic capacity during aerobic dance. J Strength Cond Res 25(12): 3479-3485, 2011-This study compared the aerobic capacity during maximal aerobic dance and treadmill running in fit women. Thirteen well-trained female aerobic dance instructors aged 30 ± 8.17 years (mean ± SD) exercised to exhaustion by running on a treadmill for measurement of maximal oxygen uptake (VO(2)max) and peak heart rate (HRpeak). Additionally, all subjects performed aerobic dancing until exhaustion after a choreographed videotaped routine trying to reach the same HRpeak as during maximal running. The p value for statistical significance between running and aerobic dance was set to ≤0.05. The results (mean ± SD) showed a lower VO(2)max in aerobic dance (52.2 ± 4.02 ml·kg·min) compared with treadmill running (55.9 ± 5.03 ml·kg·min) (p = 0.0003). Further, the mean ± SD HRpeak was 182 ± 9.15 b·min in aerobic dance and 192 ± 9.62 b·min in treadmill running, giving no difference in oxygen pulse between the 2 exercise forms (p = 0.32). There was no difference in peak ventilation (aerobic dance: 108 ± 10.81 L·min vs. running: 113 ± 11.49 L·min). In conclusion, aerobic dance does not seem to be able to use the whole aerobic capacity as in running. For well endurance-trained women, this may result in a lower total workload at maximal intensities. Aerobic dance may therefore not be as suitable as running during maximal intensities in well-trained females. PMID:22080322

  10. The Energetics of Aerobic versus Anaerobic Respiration.

    ERIC Educational Resources Information Center

    Champion, Timothy D.; Schwenz, Richard W.

    1990-01-01

    Background information, laboratory procedures, and a discussion of the results of an experiment designed to investigate the difference in energy gained from the aerobic and anaerobic oxidation of glucose are presented. Sample experimental and calculated data are included. (CW)

  11. Neuromodulation of Aerobic Exercise—A Review

    PubMed Central

    Heijnen, Saskia; Hommel, Bernhard; Kibele, Armin; Colzato, Lorenza S.

    2016-01-01

    Running, and aerobic exercise in general, is a physical activity that increasingly many people engage in but that also has become popular as a topic for scientific research. Here we review the available studies investigating whether and to which degree aerobic exercise modulates hormones, amino acids, and neurotransmitters levels. In general, it seems that factors such as genes, gender, training status, and hormonal status need to be taken into account to gain a better understanding of the neuromodular underpinnings of aerobic exercise. More research using longitudinal studies and considering individual differences is necessary to determine actual benefits. We suggest that, in order to succeed, aerobic exercise programs should include optimal periodization, prevent overtraining and be tailored to interindividual differences, including neuro-developmental and genetically-based factors. PMID:26779053

  12. Aerobic Dance for Children: Resources and Recommendations.

    ERIC Educational Resources Information Center

    Wood, Denise A.

    1986-01-01

    Aerobic dance classes may be safe for older children, but are inappropriate for children in the fourth grade and under. Programs for these children should emphasize creativity. Resources for program development are given. (MT)

  13. Conditioning and Aerobics for Older Americans.

    ERIC Educational Resources Information Center

    Hansen, Joyce

    1980-01-01

    A class designed for the maintenance and gradual improvement of senior citizens' physical fitness includes relaxation training, flexibility and stretching exercises, interval training activities (designed as a link between less strenuous exercise and more strenuous activities), and aerobic exercises. (CJ)

  14. Aerobic dynamic feeding as a strategy for in situ accumulation of polyhydroxyalkanoate in aerobic granules.

    PubMed

    Gobi, K; Vadivelu, V M

    2014-06-01

    Aerobic dynamic feeding (ADF) strategy was applied in sequencing batch reactor (SBR) to accumulate polyhydroxyalkanoate (PHA) in aerobic granules. The aerobic granules were able to remove 90% of the COD from palm oil mill effluent (POME). The volatile fatty acids (VFAs) in the POME are the sole source of the PHA accumulation. In this work, 100% removal of propionic and butyric acids in the POME were observed. The highest amount of PHA produced in aerobic granules was 0.6833mgPHA/mgbiomass. The PHA formed was identified as a P (hydroxybutyrate-co-hydroxyvalerate) P (HB-co-HV). PMID:24725384

  15. Physiological responses during aerobic dance of individuals grouped by aerobic capacity and dance experience.

    PubMed

    Thomsen, D; Ballor, D L

    1991-03-01

    This study examined the effects of aerobic capacity (peak oxygen uptake) and aerobic dance experience on the physiological responses to an aerobic dance routine. The heart rate (HR) and VO2 responses to three levels (intensities) of aerobic dance were measured in 27 women. Experienced aerobic dancers (AD) (mean peak VO2 = 42 ml.kg-1.min-1) were compared to subjects with limited aerobic dance experience of high (HI) (peak VO2 greater than 35 ml.kg-1.min-1) and low (LO) (peak VO2 less than 35 ml.kg-1.min-1) aerobic capacities. The results indicated the LO group exercised at a higher percentage of peak heart rate and peak VO2 at all three dance levels than did either the HI or AD groups (HI = AD). Design of aerobic dance routines must consider the exercise tolerance of the intended audience. In mixed groups, individuals with low aerobic capacities should be shown how and encouraged to modify the activity to reduce the level of exertion. PMID:2028095

  16. Experimental modelling of Calcium carbonate precipitation in the presence of phototrophic anaerobic bacteria Rhodovulum sp.

    NASA Astrophysics Data System (ADS)

    Bundeleva, Irina; Shirokova, Liudmila; Benezeth, Pascale; Pokrovsky, Oleg; Kompantseva, Elena

    2010-05-01

    Carbonate biomineralization is considered as one of the main natural processes controlling CO2 levels in the atmosphere both in the past and at present time. Haloalcaliphilic Rhodovulum sp. A-20s isolated from soda lake in southern Siberia and halophilic neutrophilic Rhodovulum sp. S-1765 isolated from hypersaline water body in Crimea steppe represent a large group of phototrophic bacteria likely to be involved in CaCO3 formation in soda and saline lakes. These bacteria use organic substrates for non-oxygenic photosynthesis and thus may mediate CaCO3 precipitation without CO2 consumption in highly-saline, highly-alkaline, NaHCO3-rich solutions. In order to provide the link between surface properties of bacteria and their ability to precipitate Ca carbonate, we used a combination of electrophoretic mobility measurements, surface titration and Ca ion adsorption using dead (autoclaved), inactivated (NaN3 - treated) and live cells at 25 °C as a unction of pH (3-11) and NaCl concentrations (0.01, 0.1, 0.5 M). Zeta potential of both bacteria is identical for active, NaN3-inactivated and dead cells at high ionic strength (0.5 M NaCl). The pH of isoelectric point is below 3 and zeta-potential decreases or remain negative up to pH 11. However, at lower ionic strength (0.1 M and 0.01 M NaCl) for live cells the potential increases towards positive values in the alkaline solutions (pH of 9 to 10). Similar to previous results on cyanobacteria (Martinez et al., 2009) there is a net increase in zeta-potential towards more positive values at pH = 10.4 for active cells. In order to better understand this phenomenon, experiments with different concentration of Ca2+ and HCO3- ions as well as experiments with live cultures in the darkness have been carried out. The presence in solution of Ca2+ (0.01 and 0.001 M) and the absence of light in experiment do not change significantly the potential of the cells. However, the presence in solution of HCO3- strongly reduces the zeta

  17. Localized electron transfer rates and microelectrode-based enrichment of microbial communities within a phototrophic microbial mat

    SciTech Connect

    Babauta, Jerome T.; Atci, Erhan; Ha, Phuc T.; Lindemann, Stephen R.; Ewing, Timothy; Call, Douglas R.; Fredrickson, James K.; Beyenal, Haluk

    2014-01-01

    Phototrophic microbial mats frequently exhibit sharp, light-dependent redox gradients that regulate microbial respiration on specific electron acceptors as a function of depth. In this work, a benthic phototrophic microbial mat from Hot Lake, a hypersaline, epsomitic lake located near Oroville in north-central Washington, was used to develop a microscale electrochemical method to study local electron transfer processes within the mat. To characterize the physicochemical variables influencing electron transfer, we initially quantified redox potential, pH, and dissolved oxygen gradients by depth in the mat under photic and aphotic conditions. We further demonstrated that power output of a mat fuel cell was light-dependent. To study local electron transfer processes, we deployed a microscale electrode (microelectrode) with tip size ~20 μm. To enrich a subset of microorganisms capable of interacting with the microelectrode, we anodically polarized the microelectrode at depth in the mat. Subsequently, to characterize the microelectrode- associated community and compare it to the neighboring mat community, we performed amplicon sequencing of the V1-V3 region of the 16S gene. Differences in Bray-Curtis beta diversity, illustrated by large changes in relative abundance at the phylum level, suggested successful enrichment of specific mat community members on the microelectrode surface. The microelectrode-associated community exhibited substantially reduced alpha diversity and elevated relative abundances of Prosthecochloris, Loktanella, Catellibacterium, other unclassified members of Rhodobacteraceae, Thiomicrospira, and Limnobacter, compared with the community at an equivalent depth in the mat. Our results suggest that local electron transfer to an anodically polarized microelectrode selected for a specific microbial population, with substantially more abundance and diversity of sulfur-oxidizing phylotypes compared with the neighboring mat community.

  18. Localized electron transfer rates and microelectrode-based enrichment of microbial communities within a phototrophic microbial mat.

    PubMed

    Babauta, Jerome T; Atci, Erhan; Ha, Phuc T; Lindemann, Stephen R; Ewing, Timothy; Call, Douglas R; Fredrickson, James K; Beyenal, Haluk

    2014-01-01

    Phototrophic microbial mats frequently exhibit sharp, light-dependent redox gradients that regulate microbial respiration on specific electron acceptors as a function of depth. In this work, a benthic phototrophic microbial mat from Hot Lake, a hypersaline, epsomitic lake located near Oroville in north-central Washington, was used to develop a microscale electrochemical method to study local electron transfer processes within the mat. To characterize the physicochemical variables influencing electron transfer, we initially quantified redox potential, pH, and dissolved oxygen gradients by depth in the mat under photic and aphotic conditions. We further demonstrated that power output of a mat fuel cell was light-dependent. To study local electron transfer processes, we deployed a microscale electrode (microelectrode) with tip size ~20 μm. To enrich a subset of microorganisms capable of interacting with the microelectrode, we anodically polarized the microelectrode at depth in the mat. Subsequently, to characterize the microelectrode-associated community and compare it to the neighboring mat community, we performed amplicon sequencing of the V1-V3 region of the 16S gene. Differences in Bray-Curtis beta diversity, illustrated by large changes in relative abundance at the phylum level, suggested successful enrichment of specific mat community members on the microelectrode surface. The microelectrode-associated community exhibited substantially reduced alpha diversity and elevated relative abundances of Prosthecochloris, Loktanella, Catellibacterium, other unclassified members of Rhodobacteraceae, Thiomicrospira, and Limnobacter, compared with the community at an equivalent depth in the mat. Our results suggest that local electron transfer to an anodically polarized microelectrode selected for a specific microbial population, with substantially more abundance and diversity of sulfur-oxidizing phylotypes compared with the neighboring mat community. PMID:24478768

  19. Localized electron transfer rates and microelectrode-based enrichment of microbial communities within a phototrophic microbial mat

    PubMed Central

    Babauta, Jerome T.; Atci, Erhan; Ha, Phuc T.; Lindemann, Stephen R.; Ewing, Timothy; Call, Douglas R.; Fredrickson, James K.; Beyenal, Haluk

    2014-01-01

    Phototrophic microbial mats frequently exhibit sharp, light-dependent redox gradients that regulate microbial respiration on specific electron acceptors as a function of depth. In this work, a benthic phototrophic microbial mat from Hot Lake, a hypersaline, epsomitic lake located near Oroville in north-central Washington, was used to develop a microscale electrochemical method to study local electron transfer processes within the mat. To characterize the physicochemical variables influencing electron transfer, we initially quantified redox potential, pH, and dissolved oxygen gradients by depth in the mat under photic and aphotic conditions. We further demonstrated that power output of a mat fuel cell was light-dependent. To study local electron transfer processes, we deployed a microscale electrode (microelectrode) with tip size ~20 μm. To enrich a subset of microorganisms capable of interacting with the microelectrode, we anodically polarized the microelectrode at depth in the mat. Subsequently, to characterize the microelectrode-associated community and compare it to the neighboring mat community, we performed amplicon sequencing of the V1–V3 region of the 16S gene. Differences in Bray-Curtis beta diversity, illustrated by large changes in relative abundance at the phylum level, suggested successful enrichment of specific mat community members on the microelectrode surface. The microelectrode-associated community exhibited substantially reduced alpha diversity and elevated relative abundances of Prosthecochloris, Loktanella, Catellibacterium, other unclassified members of Rhodobacteraceae, Thiomicrospira, and Limnobacter, compared with the community at an equivalent depth in the mat. Our results suggest that local electron transfer to an anodically polarized microelectrode selected for a specific microbial population, with substantially more abundance and diversity of sulfur-oxidizing phylotypes compared with the neighboring mat community. PMID:24478768

  20. Taxonomy of Aerobic Marine Eubacteria

    PubMed Central

    Baumann, Linda; Baumann, Paul; Mandel, M.; Allen, Richard D.

    1972-01-01

    Two hundred and eighteen strains of nonfermentative marine bacteria were submitted to an extensive morphological, physiological, and nutritional characterization. All the strains were gram-negative, straight or curved rods which were motile by means of polar or peritrichous flagella. A wide variety of organic substrates served as sole sources of carbon and energy. The strains differed extensively in their nutritional versatility, being able to utilize from 11 to 85 carbon compounds. Some strains had an extracellular amylase, gelatinase, lipase, or chitinase and were able to utilize n-hexadecane and to denitrify. None of the strains had a yellow, cell-associated pigment or a constitutive arginine dihydrolase system, nor were they able to hydrolyze cellulose or agar. The results of the physiological and nutritional characterization were submitted to a numerical analysis which clustered the strains into 22 groups on the basis of phenotypic similarities. The majority of these groups were separable by a large number of unrelated phenotypic traits. Analysis of the moles per cent guanine plus cytosine (GC) content in the deoxyribonucleic acid of representative strains indicated that the peritrichously flagellated groups had a GC content of 53.7 to 67.8 moles%; polarly flagellated strains had a GC content of 30.5 to 64.7 moles%. The peritrichously flagellated groups were assigned to the genus Alcaligenes. The polarly flagellated groups, which had a GC content of 43.2 to 48.0 moles%, were placed into a newly created genus, Alteromonas; groups which had a GC content of 57.8 to 64.7 moles% were placed into the genus Pseudomonas; and the remaining groups were left unassigned. Twelve groups were given the following designations: Alteromonas communis, A. vaga, A. macleodii, A. marinopraesens, Pseudomonas doudoroffi, P. marina, P. nautica, Alcaligenes pacificus, A. cupidus, A. venustus, and A. aestus. The problems of assigning species of aerobic marine bacteria to genera are

  1. Taxonomy of aerobic marine eubacteria.

    PubMed

    Baumann, L; Baumann, P; Mandel, M; Allen, R D

    1972-04-01

    Two hundred and eighteen strains of nonfermentative marine bacteria were submitted to an extensive morphological, physiological, and nutritional characterization. All the strains were gram-negative, straight or curved rods which were motile by means of polar or peritrichous flagella. A wide variety of organic substrates served as sole sources of carbon and energy. The strains differed extensively in their nutritional versatility, being able to utilize from 11 to 85 carbon compounds. Some strains had an extracellular amylase, gelatinase, lipase, or chitinase and were able to utilize n-hexadecane and to denitrify. None of the strains had a yellow, cell-associated pigment or a constitutive arginine dihydrolase system, nor were they able to hydrolyze cellulose or agar. The results of the physiological and nutritional characterization were submitted to a numerical analysis which clustered the strains into 22 groups on the basis of phenotypic similarities. The majority of these groups were separable by a large number of unrelated phenotypic traits. Analysis of the moles per cent guanine plus cytosine (GC) content in the deoxyribonucleic acid of representative strains indicated that the peritrichously flagellated groups had a GC content of 53.7 to 67.8 moles%; polarly flagellated strains had a GC content of 30.5 to 64.7 moles%. The peritrichously flagellated groups were assigned to the genus Alcaligenes. The polarly flagellated groups, which had a GC content of 43.2 to 48.0 moles%, were placed into a newly created genus, Alteromonas; groups which had a GC content of 57.8 to 64.7 moles% were placed into the genus Pseudomonas; and the remaining groups were left unassigned. Twelve groups were given the following designations: Alteromonas communis, A. vaga, A. macleodii, A. marinopraesens, Pseudomonas doudoroffi, P. marina, P. nautica, Alcaligenes pacificus, A. cupidus, A. venustus, and A. aestus. The problems of assigning species of aerobic marine bacteria to genera are

  2. Aerobic Excercise and Research Opportunities to Benefit Impaired Children. (Project AEROBIC). Final Report.

    ERIC Educational Resources Information Center

    Idaho Univ., Moscow.

    The final report summarizes accomplishments of Project AEROBIC (Aerobic Exercise and Research Opportunities to Benefit Impaired Children), which provided a physical education exercise program for severely, profoundly, and multiply handicapped children aged 10-21. Activities are outlined for the 3 year period and include modification of exercise…

  3. Metatranscriptomic analysis of a high-sulfide aquatic spring reveals insights into sulfur cycling and unexpected aerobic metabolism.

    PubMed

    Spain, Anne M; Elshahed, Mostafa S; Najar, Fares Z; Krumholz, Lee R

    2015-01-01

    Zodletone spring is a sulfide-rich spring in southwestern Oklahoma characterized by shallow, microoxic, light-exposed spring water overlaying anoxic sediments. Previously, culture-independent 16S rRNA gene based diversity surveys have revealed that Zodletone spring source sediments harbor a highly diverse microbial community, with multiple lineages putatively involved in various sulfur-cycling processes. Here, we conducted a metatranscriptomic survey of microbial populations in Zodletone spring source sediments to characterize the relative prevalence and importance of putative phototrophic, chemolithotrophic, and heterotrophic microorganisms in the sulfur cycle, the identity of lineages actively involved in various sulfur cycling processes, and the interaction between sulfur cycling and other geochemical processes at the spring source. Sediment samples at the spring's source were taken at three different times within a 24-h period for geochemical analyses and RNA sequencing. In depth mining of datasets for sulfur cycling transcripts revealed major sulfur cycling pathways and taxa involved, including an unexpected potential role of Actinobacteria in sulfide oxidation and thiosulfate transformation. Surprisingly, transcripts coding for the cyanobacterial Photosystem II D1 protein, methane monooxygenase, and terminal cytochrome oxidases were encountered, indicating that genes for oxygen production and aerobic modes of metabolism are actively being transcribed, despite below-detectable levels (<1 µM) of oxygen in source sediment. Results highlight transcripts involved in sulfur, methane, and oxygen cycles, propose that oxygenic photosynthesis could support aerobic methane and sulfide oxidation in anoxic sediments exposed to sunlight, and provide a viewpoint of microbial metabolic lifestyles under conditions similar to those seen during late Archaean and Proterozoic eons. PMID:26417542

  4. Metatranscriptomic analysis of a high-sulfide aquatic spring reveals insights into sulfur cycling and unexpected aerobic metabolism

    PubMed Central

    Elshahed, Mostafa S.; Najar, Fares Z.; Krumholz, Lee R.

    2015-01-01

    Zodletone spring is a sulfide-rich spring in southwestern Oklahoma characterized by shallow, microoxic, light-exposed spring water overlaying anoxic sediments. Previously, culture-independent 16S rRNA gene based diversity surveys have revealed that Zodletone spring source sediments harbor a highly diverse microbial community, with multiple lineages putatively involved in various sulfur-cycling processes. Here, we conducted a metatranscriptomic survey of microbial populations in Zodletone spring source sediments to characterize the relative prevalence and importance of putative phototrophic, chemolithotrophic, and heterotrophic microorganisms in the sulfur cycle, the identity of lineages actively involved in various sulfur cycling processes, and the interaction between sulfur cycling and other geochemical processes at the spring source. Sediment samples at the spring’s source were taken at three different times within a 24-h period for geochemical analyses and RNA sequencing. In depth mining of datasets for sulfur cycling transcripts revealed major sulfur cycling pathways and taxa involved, including an unexpected potential role of Actinobacteria in sulfide oxidation and thiosulfate transformation. Surprisingly, transcripts coding for the cyanobacterial Photosystem II D1 protein, methane monooxygenase, and terminal cytochrome oxidases were encountered, indicating that genes for oxygen production and aerobic modes of metabolism are actively being transcribed, despite below-detectable levels (<1 µM) of oxygen in source sediment. Results highlight transcripts involved in sulfur, methane, and oxygen cycles, propose that oxygenic photosynthesis could support aerobic methane and sulfide oxidation in anoxic sediments exposed to sunlight, and provide a viewpoint of microbial metabolic lifestyles under conditions similar to those seen during late Archaean and Proterozoic eons. PMID:26417542

  5. Controlling the catalytic aerobic oxidation of phenols.

    PubMed

    Esguerra, Kenneth Virgel N; Fall, Yacoub; Petitjean, Laurène; Lumb, Jean-Philip

    2014-05-28

    The oxidation of phenols is the subject of extensive investigation, but there are few catalytic aerobic examples that are chemo- and regioselective. Here we describe conditions for the ortho-oxygenation or oxidative coupling of phenols under copper (Cu)-catalyzed aerobic conditions that give rise to ortho-quinones, biphenols or benzoxepines. We demonstrate that each product class can be accessed selectively by the appropriate choice of Cu(I) salt, amine ligand, desiccant and reaction temperature. In addition, we evaluate the effects of substituents on the phenol and demonstrate their influence on selectivity between ortho-oxygenation and oxidative coupling pathways. These results create an important precedent of catalyst control in the catalytic aerobic oxidation of phenols and set the stage for future development of catalytic systems and mechanistic investigations. PMID:24784319

  6. [Anaerobic-aerobic infection in acute appendicitis].

    PubMed

    Mamchich, V I; Ulitovskiĭ, I V; Savich, E I; Znamenskiĭ, V A; Beliaeva, O A

    1998-01-01

    362 patients with acute appendicitis (AA) were examined. For microbiological diagnosis of aerobic and anaerobic nonclostridial microflora we used complex accelerated methods (including evaluation of gram-negative microorganisms in comparison with tinctorial-fermentative method of differential staining according to oxygen sensitivity of catalasopositive together with aerobic and cathalasonegative anaerobic microorganisms) as well as complete bacteriologic examination with determination of sensitivity of the above microorganism to antimicrobial remedies. High rate of aerobic-anaerobic microbial associations and substantial identity of microflora from appendicis and exudate from abdominal cavity was revealed, which evidenced the leading role of endogenous microorganisms in etiology and pathogenesis of AA and peritonitis i. e. autoinfection. In patients with destructive forms of AA, complicated by peritonitis it is recommended to use the accelerated method of examination of pathologic material as well as the complete scheme of examination with the identification of the isolated microorganisms and the correction of antibiotic treatment. PMID:9511291

  7. Aerobic biodegradation of trichloroethene without auxiliary substrates.

    PubMed

    Schmidt, Kathrin R; Gaza, Sarah; Voropaev, Andrey; Ertl, Siegmund; Tiehm, Andreas

    2014-08-01

    Trichloroethene (TCE) represents a priority pollutant and is among the most frequently detected contaminants in groundwater. The current bioremediation measures have certain drawbacks like e.g. the need for auxiliary substrates. Here, the aerobic biodegradation of TCE as the sole growth substrate is demonstrated. This new process of metabolic TCE degradation was first detected in groundwater samples. TCE degradation was stable in an enriched mixed bacterial culture in mineral salts medium for over five years and repeated transfers of the culture resulting in a 10(10) times dilution of the original groundwater. Aerobic TCE degradation resulted in stoichiometric chloride formation. Stable carbon isotope fractionation was observed providing a reliable analytical tool to assess this new biodegradation process at field sites. The results suggest that aerobic biodegradation of TCE without auxiliary substrate could be considered as an option for natural attenuation or engineered bioremediation of contaminated sites. PMID:24793109

  8. Drying and recovery of aerobic granules.

    PubMed

    Hu, Jianjun; Zhang, Quanguo; Chen, Yu-You; Lee, Duu-Jong

    2016-10-01

    To dehydrate aerobic granules to bone-dry form was proposed as a promising option for long-term storage of aerobic granules. This study cultivated aerobic granules with high proteins/polysaccharide ratio and then dried these granules using seven protocols: drying at 37°C, 60°C, 4°C, under sunlight, in dark, in a flowing air stream or in concentrated acetone solutions. All dried granules experienced volume shrinkage of over 80% without major structural breakdown. After three recovery batches, although with loss of part of the volatile suspended solids, all dried granules were restored most of their original size and organic matter degradation capabilities. The strains that can survive over the drying and storage periods were also identified. Once the granules were dried, they can be stored over long period of time, with minimal impact yielded by the applied drying protocols. PMID:27392096

  9. Aerobic transformation of cadmium through metal sulfide biosynthesis in photosynthetic microorganisms

    PubMed Central

    2013-01-01

    Background Cadmium is a non-essential metal that is toxic because of its interference with essential metals such as iron, calcium and zinc causing numerous detrimental metabolic and cellular effects. The amount of this metal in the environment has increased dramatically since the advent of the industrial age as a result of mining activities, the use of fertilizers and sewage sludge in farming, and discharges from manufacturing activities. The metal bioremediation utility of phototrophic microbes has been demonstrated through their ability to detoxify Hg(II) into HgS under aerobic conditions. Metal sulfides are generally very insoluble and therefore, biologically unavailable. Results When Cd(II) was exposed to cells it was bioconverted into CdS by the green alga Chlamydomonas reinhardtii, the red alga Cyanidioschyzon merolae, and the cyanobacterium, Synechoccocus leopoliensis. Supplementation of the two eukaryotic algae with extra sulfate, but not sulfite or cysteine, increased their cadmium tolerances as well as their abilities to produce CdS, indicating an involvement of sulfate assimilation in the detoxification process. However, the combined activities of extracted serine acetyl-transferase (SAT) and O-acetylserine(thiol)lyase (OASTL) used to monitor sulfate assimilation, was not significantly elevated during cell treatments that favored sulfide biosynthesis. It is possible that the prolonged incubation of the experiments occurring over two days could have compensated for the low rates of sulfate assimilation. This was also the case for S. leopoliensis where sulfite and cysteine as well as sulfate supplementation enhanced CdS synthesis. In general, conditions that increased cadmium sulfide production also resulted in elevated cysteine desulfhydrase activities, strongly suggesting that cysteine is the direct source of sulfur for CdS synthesis. Conclusions Cadmium(II) tolerance and CdS formation were significantly enhanced by sulfate supplementation, thus

  10. Combined stable isotope, proteomic, metabolomics, and spatial specific analysis to track carbon flow through a hypersaline phototrophic microbial mat

    NASA Astrophysics Data System (ADS)

    Moran, J.; Cory, A.; Riha, K. M.; Huang, E. L.; Gritsenko, M. A.; Kim, Y. M.; Metz, T. O.; Lipton, M. S.

    2014-12-01

    Tracking labeled substrates through microbial mat systems can help elucidate carbon dynamics, species interactions, and niche partitioning, but the inherent microbial complexity of these systems makes them difficult to probe with single analytical techniques. Here we use a combination of different tools to track three labeled substrates through a benthic phototrophic mat from Hot Lake. Hot Lake is a hypersaline, meromictic lake located in an endorheic basin in north-central Washington which, despite extreme salinity and seasonal water temperatures (> 55 ˚C), hosts dense, phototrophic benthic microbial mats. Cyanobacteria are the dominant CO2-fixing organisms in the system and we seek to understand the spatial and metabolic controls on how the carbon initially fixed by mat cyanobacteria is transferred to associated heterotrophic populations spread throughout the mat strata. We performed ex situ incubations over a complete diel cycle with 13C labeled bicarbonate, acetate, and glucose. Traditional elemental analysis IRMS provided an estimate of bulk label uptake to total biomass and showed that both bicarbonate and acetate were incorporated only during daylight while glucose uptake was nearly constant through the cycle. Spatially resolved isotope analysis using laser ablation IRMS showed distinctive patterns between the different substrates with bicarbonate having highest uptake in the top third of the mat, acetate uptake focused near the mat's center, and glucose showing similar uptake at all mat depths. Proteomic analysis showed a longer lag in substrate conversion to protein than to biomass and a distinct spike in the number of labeled peptides in the bicarbonate incubation near the end of the diel cycle. Proteomic analysis confirmed that photosynthetic organisms showed the highest rates of label conversion to protein but heterotrophic organisms also incorporated label into their peptides. Metabolomic analysis demonstrated the high conversion of organic substrates

  11. INACTIVATION OF ENTERIC PATHOGENS DURING AEROBIC DIGESTION OF WASTEWATER SLUDGE

    EPA Science Inventory

    The effects of aerobic and anaerobic digestion on enteric viruses, enteric bacteria, total aerobic bacteria, and intestinal parasites were studied under laboratory and field conditions. Under laboratory conditions, the temperature of the sludge digestion was the major factor infl...

  12. ANAEROBIC AND AEROBIC TREATMENT OF CHLORINATED ALIPHATIC COMPOUNDS

    EPA Science Inventory

    Biological degradation of 12 chlorinated aliphatic compounds (CACs) was assessed in bench-top reactors and in serum bottle tests. Three continuously mixed daily batch-fed reactor systems were evaluated: anaerobic, aerobic, and sequential-anaerobic-aerobic (sequential). Glucose,...

  13. Reflections on Psychotherapy and Aerobic Exercise.

    ERIC Educational Resources Information Center

    Silverman, Wade

    This document provides a series of reflections by a practicing psychologist on the uses of aerobic workouts in psychotherapy. Two case histories are cited to illustrate the contention that the mode of exercise, rather than simply its presence or absence, is the significant indicator of a patient's emotional well-being or psychopathology. The first…

  14. Aerobic Exercise Prescription for Rheumatoid Arthritics.

    ERIC Educational Resources Information Center

    Evans, Blanche W.; Williams, Hilda L.

    The use of exercise as a general treatment for rheumatoid arthritics (RA) has included range of motion, muscular strength, water exercise and rest therapy while virtually ignoring possible benefits of aerobic exercise. The purposes of this project were to examine the guidelines for exercise prescription in relation to this special population and…

  15. Response of aerobic rice to Piriformospora indica.

    PubMed

    Das, Joy; Ramesh, K V; Maithri, U; Mutangana, D; Suresh, C K

    2014-03-01

    Rice cultivation under aerobic condition not only saves water but also opens up a splendid scope for effective application of beneficial root symbionts in rice crop unlike conventional puddled rice cultivation where water logged condition acts as constraint for easy proliferation of various beneficial soil microorganisms like arbuscular mycorrhizal (AM) fungi. Keeping these in view, an in silico investigation were carried out to explore the interaction of hydrogen phosphate with phosphate transporter protein (PTP) from P. indica. This was followed by greenhouse investigation to study the response of aerobic rice to Glomusfasciculatum, a conventional P biofertilizer and P. indica, an alternative to AM fungi. Computational studies using ClustalW tool revealed several conserved motifs between the phosphate transporters from Piriformospora indica and 8 other Glomus species. The 3D model of PTP from P. indica resembling "Mayan temple" was successfully docked onto hydrogen phosphate, indicating the affinity of this protein for inorganic phosphorus. Greenhouse studies revealed inoculation of aerobic rice either with P. indica, G. fasciculatum or both significantly enhanced the plant growth, biomass and yield with higher NPK, chlorophyll and sugar compared to uninoculated ones, P. indica inoculated plants being superior. A significantly enhanced activity of acid phosphatase and alkaline phosphatase were noticed in the rhizosphere soil of rice plants inoculated either with P. indica, G. fasciculatum or both, contributing to higher P uptake. Further, inoculation of aerobic rice plants with P. indica proved to be a better choice as a potential biofertilizer over mycorrhiza. PMID:24669667

  16. Media for the aerobic growth of campylobacter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of agar and sodium bicarbonate (NaHCO3) concentration on aerobic growth of Campylobacter in a fumarate-pyruvate medium was examined. The broth medium was supplemented with 0.0 to 0.2% agar and inoculated with 106 CFU/ml of Campylobacter coli 33559, Campylobacter fetus 27349, Campylobacter...

  17. Strengthening aerobic granule by salt precipitation.

    PubMed

    Chen, Yu-You; Pan, Xiangliang; Li, Jun; Lee, Duu-Jong

    2016-10-01

    Structural stability of aerobic granules is generally poor during long-term operation. This study precipitated seven salts inside aerobic granules using supersaturated solutions of (NH4)3PO4, CaCO3, CaSO4, MgCO3, Mg3(PO4)2, Ca3(PO4)2 or SiO2 to enhance their structural stability. All precipitated granules have higher interior strength at ultrasonic field and reveal minimal loss in organic matter degradation capability at 160-d sequential batch reactor tests. The strength enhancement followed: Mg3(PO4)2=CaSO4>SiO2>(NH4)3PO4>MgCO3>CaCO3=Ca3(PO4)2>original. Also, the intra-granular solution environment can be buffered by the precipitate MgCO3 to make the aerobic granules capable of degradation of organic matters at pH 3. Salt precipitation is confirmed a simple and cost-effective modification method to extend the applicability of aerobic granules for wastewater treatments. PMID:27377228

  18. AEROBIC DENITRIFICATION: IMPLICATIONS FOR NITROGEN FATE MODELING

    EPA Science Inventory

    In the Mississippi, as well as most nitrogen-degraded rivers and streams, NO3- is the dominant N species and therefore understanding its biogeochemical behavior is critical for accurate nitrogen fate modeling. To our knowledge this is the first work to report aerobic denitrificat...

  19. Anaerobic and aerobic transformation of TNT

    SciTech Connect

    Kulpa, C.F.; Boopathy, R.; Manning, J.

    1996-12-31

    Most studies on the microbial metabolism of nitroaromatic compounds have used pure cultures of aerobic microorganisms. In many cases, attempts to degrade nitroaromatics under aerobic conditions by pure cultures result in no mineralization and only superficial modifications of the structure. However, mixed culture systems properly operated result in the transformation of 2,4,6-trinitrotoluene (TNT) and in some cases mineralization of TNT occurs. In this paper, the mixed culture system is described with emphasis on intermediates and the characteristics of the aerobic microbial process including the necessity for a co-substrate. The possibility of removing TNT under aerobic/anoxic conditions is described in detail. Another option for the biodegradation of TNT and nitroaromatics is under anaerobic, sulfate reducing conditions. In this instance, the nitroaromatic compounds undergo a series of reductions with the formation of amino compounds. TNT under sulfate reducing conditions is reduced to triaminotoluene presumably by the enzyme nitrite reductase, which is commonly found in many Desulfovibrio spp. The removal of nitro groups from TNT is achieved by a series of reductive reactions with the formation of ammonia and toluene by Desulfovibrio sp. (B strain). These metabolic processes could be applied to other nitroaromatic compounds like nitrobenzene, nitrobenzoic acids, nitrophenols, and aniline. The data supporting the anaerobic transformation of TNT under different growth condition are reviewed in this report.

  20. Ventilation and Speech Characteristics during Submaximal Aerobic Exercise

    ERIC Educational Resources Information Center

    Baker, Susan E.; Hipp, Jenny; Alessio, Helaine

    2008-01-01

    Purpose: This study examined alterations in ventilation and speech characteristics as well as perceived dyspnea during submaximal aerobic exercise tasks. Method: Twelve healthy participants completed aerobic exercise-only and simultaneous speaking and aerobic exercise tasks at 50% and 75% of their maximum oxygen consumption (VO[subscript 2] max).…

  1. Adolescents' Interest and Performances in Aerobic Fitness Testing

    ERIC Educational Resources Information Center

    Zhu, Xihe; Chen, Senlin; Parrott, James

    2014-01-01

    This study examined adolescents' interest in aerobic fitness testing and its relation to the test performances. Adolescents (N = 356) from three middle schools participated in the study. The participants took two aerobic fitness tests: the Progressive Aerobic Cardiovascular Endurance Run (PACER) and One-Mile Run (1MR) with a two-day interval,…

  2. Marine Chloroflexus-like Organisms Synthesize Mid-Chain Branched Monomethylalkanes

    NASA Astrophysics Data System (ADS)

    Parenteau, M. N.; Jahnke, L. L.; Green, S. J.; Boomer, S. M.; Pierson, B. K.

    2010-04-01

    Mid-chain branched mono- and dimethylalkanes (MMA and DMA, respectively) are considered biomarkers for cyanobacteria. In this study, we report the synthesis of a series of MMAs by anoxygenic phototrophic marine Chloroflexus-like organisms (MCLOs).

  3. Monoseptic cultivation of phototrophic microorganisms--development and scale-up of a photobioreactor system with thermal sterilization.

    PubMed

    Walter, Christian; Steinau, Torsten; Gerbsch, Norbert; Buchholz, Rainer

    2003-07-01

    The use of phototrophic microorganisms as sources of biological active substances in photoautotrophic and mixotrophic cultivation modes requires an adequate cultivation system with thermal sterilization. A corresponding photobioreactor system in the 10, 25 and 100 l scales was developed. This "Medusa"-photobioreactor system represents a concept based on the air-lift loop principle, whose working volume is irradiated by external light sources. The incident irradiation can be varied by a light control system. An effective CO(2)/O(2) gas exchange is enabled due to the efficient supply with process gas by several gas supply nozzles within the system and a large degassing surface. Using a model to describe the growth characteristics of the organisms, the volumetric irradiation coefficient I(DX) was defined as scale-up parameter. On this basis the scale-up from 1 l bubble columns to the 10 and 100 l scales was realized. The scale-up was performed successfully with Chlorella salina as model organism. A maximum biomass concentration of 7.89 g (dry weight) l(-1) at a maximum specific growth rate of 0.058 h(-1) and a yield of 35 mg l(-1) h(-1) was obtained in a batch cultivation in the 100 l scale under photoautotrophic conditions with an initial biomass concentration of approx. 0.03 g l(-1). PMID:12919807

  4. The Behavior of Organic Phosphorus under Non-Point Source Wastewater in the Presence of Phototrophic Periphyton

    PubMed Central

    Lu, Haiying; Yang, Linzhang; Zhang, Shanqing; Wu, Yonghong

    2014-01-01

    To understand the role of ubiquitous phototrophic periphyton in aquatic ecosystem on the biogeochemical cycling of organic phosphorus, the conversion and removal kinetic characteristics of organic phosphorus (Porg) such as adenosine triphosphate (ATP) were investigated in the presence of the periphyton cultured in artificial non-point source wastewater. The preliminary results showed that the periphyton was very powerful in converting Porg evidenced by the fact that inorganic phosphorus (Pinorg) content in solution increased from about 0.7 to 14.3 mg P L−1 in 48 hours in the presence of 0.6 g L−1 periphyton. This was because the periphyton could produce abundant phosphatases that benefited the conversion of Porg to Pinrog. Moreover, this conversion process was described more suitable by the pseudo-first-order kinetic model. The periphyton was also effective in removing Porg, which showed that the Porg can be completely removed even when the initial Porg concentration was as high as 13 mg P L−1 in 48 hours in the presence of 1.6 g L−1 periphyton. Furthermore, it was found that biosorption dominated the Porg removal process and exhibited the characteristics of physical adsorption. However, this biosorption process by the periphyton was significantly influenced by biomass (absorbent dosage) and temperature. This work provides insights into Porg biogeochemical circulation of aquatic ecosystem that contained the periphyton or similar microbial aggregates. PMID:24465782

  5. Diversity of purple nonsulfur bacteria in shrimp ponds with varying mercury levels.

    PubMed

    Mukkata, Kanokwan; Kantachote, Duangporn; Wittayaweerasak, Banjong; Techkarnjanaruk, Somkiet; Boonapatcharoen, Nimaradee

    2016-07-01

    This research aimed to study the diversity of purple nonsulfur bacteria (PNSB) and to investigate the effect of Hg concentrations in shrimp ponds on PNSB diversity. Amplification of the pufM gene was detected in 13 and 10 samples of water and sediment collected from 16 shrimp ponds in Southern Thailand. In addition to PNSB, other anoxygenic phototrophic bacteria (APB) were also observed; purple sulfur bacteria (PSB) and aerobic anoxygenic phototrophic bacteria (AAPB) although most of them could not be identified. Among identified groups; AAPB, PSB and PNSB in the samples of water and sediment were 25.71, 11.43 and 8.57%; and 27.78, 11.11 and 22.22%, respectively. In both sample types, Roseobacter denitrificans (AAPB) was the most dominant species followed by Halorhodospira halophila (PSB). In addition two genera, observed most frequently in the sediment samples were a group of PNSB (Rhodovulum kholense, Rhodospirillum centenum and Rhodobium marinum). The UPGMA dendrograms showed 7 and 6 clustered groups in the water and sediment samples, respectively. There was no relationship between the clustered groups and the total Hg (HgT) concentrations in the water and sediment samples used (<0.002-0.03 μg/L and 35.40-391.60 μg/kg dry weight) for studying the biodiversity. It can be concluded that there was no effect of the various Hg levels on the diversity of detected APB species; particularly the PNSB in the shrimp ponds. PMID:27298580

  6. Taxonomic and Functional Metagenomic Signature of Turfs in the Abrolhos Reef System (Brazil)

    PubMed Central

    Walter, Juline M.; Tschoeke, Diogo A.; Meirelles, Pedro M.; de Oliveira, Louisi; Leomil, Luciana; Tenório, Márcio; Valle, Rogério; Salomon, Paulo S.; Thompson, Cristiane C.; Thompson, Fabiano L.

    2016-01-01

    Turfs are widespread assemblages (consisting of microbes and algae) that inhabit reef systems. They are the most abundant benthic component in the Abrolhos reef system (Brazil), representing greater than half the coverage of the entire benthic community. Their presence is associated with a reduction in three-dimensional coral reef complexity and decreases the habitats available for reef biodiversity. Despite their importance, the taxonomic and functional diversity of turfs remain unclear. We performed a metagenomics and pigments profile characterization of turfs from the Abrolhos reefs. Turf microbiome primarily encompassed Proteobacteria (mean 40.57% ± s.d. 10.36, N = 1.548,192), Cyanobacteria (mean 35.04% ± s.d. 15.5, N = 1.337,196), and Bacteroidetes (mean 11.12% ± s.d. 4.25, N = 424,185). Oxygenic and anoxygenic phototrophs, chemolithotrophs, and aerobic anoxygenic phototrophic (AANP) bacteria showed a conserved functional trait of the turf microbiomes. Genes associated with oxygenic photosynthesis, AANP, sulfur cycle (S oxidation, and DMSP consumption), and nitrogen metabolism (N2 fixation, ammonia assimilation, dissimilatory nitrate and nitrite ammonification) were found in the turf microbiomes. Principal component analyses of the most abundant taxa and functions showed that turf microbiomes differ from the other major Abrolhos benthic microbiomes (i.e., corals and rhodoliths) and seawater. Taken together, these features suggest that turfs have a homogeneous functional core across the Abrolhos Bank, which holds diverse microbial guilds when comparing with other benthic organisms. PMID:27548380

  7. Taxonomic and Functional Metagenomic Signature of Turfs in the Abrolhos Reef System (Brazil).

    PubMed

    Walter, Juline M; Tschoeke, Diogo A; Meirelles, Pedro M; de Oliveira, Louisi; Leomil, Luciana; Tenório, Márcio; Valle, Rogério; Salomon, Paulo S; Thompson, Cristiane C; Thompson, Fabiano L

    2016-01-01

    Turfs are widespread assemblages (consisting of microbes and algae) that inhabit reef systems. They are the most abundant benthic component in the Abrolhos reef system (Brazil), representing greater than half the coverage of the entire benthic community. Their presence is associated with a reduction in three-dimensional coral reef complexity and decreases the habitats available for reef biodiversity. Despite their importance, the taxonomic and functional diversity of turfs remain unclear. We performed a metagenomics and pigments profile characterization of turfs from the Abrolhos reefs. Turf microbiome primarily encompassed Proteobacteria (mean 40.57% ± s.d. 10.36, N = 1.548,192), Cyanobacteria (mean 35.04% ± s.d. 15.5, N = 1.337,196), and Bacteroidetes (mean 11.12% ± s.d. 4.25, N = 424,185). Oxygenic and anoxygenic phototrophs, chemolithotrophs, and aerobic anoxygenic phototrophic (AANP) bacteria showed a conserved functional trait of the turf microbiomes. Genes associated with oxygenic photosynthesis, AANP, sulfur cycle (S oxidation, and DMSP consumption), and nitrogen metabolism (N2 fixation, ammonia assimilation, dissimilatory nitrate and nitrite ammonification) were found in the turf microbiomes. Principal component analyses of the most abundant taxa and functions showed that turf microbiomes differ from the other major Abrolhos benthic microbiomes (i.e., corals and rhodoliths) and seawater. Taken together, these features suggest that turfs have a homogeneous functional core across the Abrolhos Bank, which holds diverse microbial guilds when comparing with other benthic organisms. PMID:27548380

  8. [Research advances in denitrogenation characteristics of aerobic denitrifiers].

    PubMed

    Liang, Shu-Cheng; Zhao, Min; Lu, Lei; Zhao, Li-Yan

    2010-06-01

    The discovery of aerobic denitrifiers is the enrichment and breakthrough of traditional denitrification theory. Owing to their unique superiority in denitrogenation, aerobic denitrifiers have become a hotspot in the study of bio-denitrogenation of waste water. Under aerobic conditions, the aerobic denitrifiers can utilize organic carbon sources for their growth, and produce N2 from nitrate and nitrite. Most of the denitrifiers can also proceed with heterotrophic nitrification simultaneously, transforming NH4(+)-N to gaseous nitrogen. In this paper, the denitrogenation characteristics and action mechanisms of some isolated aerobic denitrifiers were discussed from the aspects of electron theory and denitrifying enzyme system. The effects of the environmental factors DO, carbon sources, and C/N on the denitrogenation process of aerobic denitrifiers were analyzed, and the screening methods as well as the present and potential applications of aerobic denitrifiers in wastewater treatment were described and discussed. PMID:20873638

  9. Aerobic workout and bone mass in females.

    PubMed

    Alfredson, H; Nordström, P; Lorentzon, R

    1997-12-01

    This cross-sectional study aimed to investigate bone mass in females participating in aerobic workout. Twenty-three females (age 24.1 +/- 2.7 years), participating in aerobic workout for about 3 hours/week, were compared with 23 age-, weight- and height-matched non-active females. Areal bone mineral density (BMD) was measured in total body, head, whole dominant humerus, lumbar spine, right femoral neck, Ward's triangle, trochanter femoris, in specific sites in right femur diaphysis, distal femur, proximal tibia and tibial diaphysis, and bone mineral content (BMC) was measured in the whole dominant arm and right leg, using dual energy X-ray absorptiometry. The aerobic workout group had significantly (P < 0.05-0.01) higher BMD in total body (3.7%), lumbar spine (7.8%), femoral neck (11.6%), Ward's triangle (11.7%), trochanter femoris (9.6%), proximal tibia (6.8%) and tibia diaphysis (5.9%) compared to the non-active controls. There were no differences between the groups concerning BMD of the whole dominant humerus, femoral diaphysis, distal femur and BMC and lean mass of the whole dominant arm and right leg. Leaness of the whole dominant arm and leg was correlated to BMC of the whole dominant arm and right leg in both groups. In young females, aerobic workout containing alternating high and low impact movements for the lower body is associated with a higher bone mass in clinically important sites like the lumbar spine and hip, but muscle strengthening exercises like push-ups and soft-glove boxing are not associated with a higher bone mass in the dominant humerus. It appears that there is a skeletal adaptation to the loads of the activity. PMID:9458499

  10. Nitrification and aerobic denitrification in anoxic-aerobic sequencing batch reactor.

    PubMed

    Alzate Marin, Juan C; Caravelli, Alejandro H; Zaritzky, Noemí E

    2016-01-01

    The aim of this study was to evaluate the feasibility of achieving nitrogen (N) removal using a lab-scale sequencing batch reactor (SBR) exposed to anoxic/aerobic (AN/OX) phases, focusing to achieve aerobic denitrification. This process will minimize emissions of N2O greenhouse gas. The effects of different operating parameters on the reactor performance were studied: cycle duration, AN/OX ratio, pH, dissolved oxygen concentration (DOC), and organic load. The highest inorganic N removal (NiR), close to 70%, was obtained at pH=7.5, low organic load (440mgCOD/(Lday)) and high aeration given by 12h cycle, AN/OX ratio=0.5:1.0 and DOC higher than 4.0mgO2/L. Nitrification followed by high-rate aerobic denitrification took place during the aerobic phase. Aerobic denitrification could be attributed to Tetrad-forming organisms (TFOs) with phenotype of glycogen accumulating organisms using polyhydroxyalkanoate and/or glycogen storage. The proposed AN/OX system constitutes an eco-friendly N removal process providing N2 as the end product. PMID:26512862

  11. Aerobic and two-stage anaerobic-aerobic sludge digestion with pure oxygen and air aeration.

    PubMed

    Zupancic, Gregor D; Ros, Milenko

    2008-01-01

    The degradability of excess activated sludge from a wastewater treatment plant was studied. The objective was establishing the degree of degradation using either air or pure oxygen at different temperatures. Sludge treated with pure oxygen was degraded at temperatures from 22 degrees C to 50 degrees C while samples treated with air were degraded between 32 degrees C and 65 degrees C. Using air, sludge is efficiently degraded at 37 degrees C and at 50-55 degrees C. With oxygen, sludge was most effectively degraded at 38 degrees C or at 25-30 degrees C. Two-stage anaerobic-aerobic processes were studied. The first anaerobic stage was always operated for 5 days HRT, and the second stage involved aeration with pure oxygen and an HRT between 5 and 10 days. Under these conditions, there is 53.5% VSS removal and 55.4% COD degradation at 15 days HRT - 5 days anaerobic, 10 days aerobic. Sludge digested with pure oxygen at 25 degrees C in a batch reactor converted 48% of sludge total Kjeldahl nitrogen to nitrate. Addition of an aerobic stage with pure oxygen aeration to the anaerobic digestion enhances ammonium nitrogen removal. In a two-stage anaerobic-aerobic sludge digestion process within 8 days HRT of the aerobic stage, the removal of ammonium nitrogen was 85%. PMID:17251012

  12. Improved short-term toxicity test protocol to assess metal tolerance in phototrophic periphyton: toward standardization of PICT approaches.

    PubMed

    Lambert, Anne Sophie; Pesce, Stéphane; Foulquier, Arnaud; Gahou, Josiane; Coquery, Marina; Dabrin, Aymeric

    2015-03-01

    Pollution-induced community tolerance (PICT) approaches involve comparing tolerance levels of natural communities to a particular contaminant or a contaminant mixture using short-term toxicity tests performed under controlled conditions. However, results from toxicity tests can be modulated by various environmental and experimental conditions, raising questions about their reproducibility and comparability. In this context, the present study aimed to determine the influence of exposure duration, periphyton suspension concentration, and periphyton maturation stage on the measurement of short-term effects of copper on phototrophic periphyton communities. Our results showed the very weak influence of exposure duration in the tested range (2-6 h) on toxicity level, whereas periphyton biomass in the tested suspension (in terms of both chlorophyll a concentrations and dry weight), proved a crucial determinant in toxicity assessment. Results also highlighted the potential tolerance increase with the periphyton maturation stage. This parameter conditioned the positive linear relationship between tolerance level and periphyton suspension concentration, leading to an increase in the linear regression slope with the maturation stage. This suggests that such a relationship is probably highly periphyton-dependent. Consequently, to enable data toxicity comparisons, an a priori normalization of the periphyton suspension biomass is necessary, and PICT approaches require the use, as much of possible, of periphyton with similar maturation stage. Finally, the present study clearly shows that a better standardization of PICT approaches could help to improve reproducibility. It could thus facilitate the comparison of tolerance levels measured in the same study (e.g., spatial and/or temporal and/or inter-treatment comparison) as well as the comparison obtained from different experimental and in situ research. PMID:25167827

  13. Association of a new type of gliding, filamentous, purple phototrophic bacterium inside bundles of Microcoleus chthonoplastes in hypersaline cyanobacterial mats

    NASA Technical Reports Server (NTRS)

    D'Amelio, E. D.; Cohen, Y.; Des Marais, D. J.

    1987-01-01

    bacteria is not available yet in pure culture, and its taxonomical position cannot be fully established. This organism is suggested to be a new type of gliding, filamentous, purple phototroph.

  14. Raman imaging in geomicrobiology: endolithic phototrophic microorganisms in gypsum from the extreme sun irradiation area in the Atacama Desert.

    PubMed

    Vítek, Petr; Ascaso, Carmen; Artieda, Octavio; Wierzchos, Jacek

    2016-06-01

    The Raman imaging method was successfully applied for mapping the distribution of biomolecules (e.g., pigments) associated with cryptoendolithic and hypoendolithic microorganisms, as well as the inorganic host mineral matrix that forms the habitat for the biota. To the best of our knowledge, this is the first comprehensive study in the field of geomicrobiology based on this technique. The studied microbial ecosystem was located nearly 3000 m above sea level within the driest desert on Earth, the Atacama in Chile. Enhancement of carotenoid Raman signal intensity close to the surface was registered at different areas of endolithic colonization dominated by algae, with cyanobacteria present as well. This is interpreted as an adaptation mechanism to the excessive solar irradiation. On the other hand, cyanobacteria synthesize scytonemin as a passive UV-screening pigment (found at both the hypoendolithic and cryptoendolithic positions). The distribution of the scytonemin Raman signal was mapped simultaneously with the surrounding mineral matrix. Thus, mapping was done of the phototrophic microorganisms in their original microhabitat together with the host rock environment. Important information which was resolved from the Raman imaging dataset of the host rock is about the hydration state of Ca-sulfate, demonstrated on the presence of gypsum (CaSO4·2H2O) and the absence of both anhydrite (CaSO4) and bassanite (CaSO4·1/2H2O). Obtaining combined "in situ" simultaneous information from the geological matrix (inorganic) together with the microbial biomolecules (organic) is discussed and concluded as an important advantage of this technique. We discuss how selection of the laser wavelength (785 and 514.5-nm) influences the Raman imaging results. PMID:27055886

  15. Urea Utilization in the Phototrophic Bacterium Rhodobacter capsulatus Is Regulated by the Transcriptional Activator NtrC

    PubMed Central

    Masepohl, Bernd; Kaiser, Björn; Isakovic, Nazila; Richard, Cynthia L.; Kranz, Robert G.; Klipp, Werner

    2001-01-01

    The phototrophic nonsulfur purple bacterium Rhodobacter capsulatus can use urea as a sole source of nitrogen. Three transposon Tn5-induced mutations (Xan-9, Xan-10, and Xan-19), which led to a Ure− phenotype, were mapped to the ureF and ureC genes, whereas two other Tn5 insertions (Xan-20 and Xan-22) were located within the ntrC and ntrB genes, respectively. As in Klebsiella aerogenes and other bacteria, the genes encoding urease (ureABC) and the genes required for assembly of the nickel metallocenter (ureD and ureEFG) are clustered in R. capsulatus (ureDABC-orf136-ureEFG). No homologues of Orf136 were found in the databases, and mutational analysis demonstrated that orf136 is not essential for urease activity or growth on urea. Analysis of a ureDA-lacZ fusion showed that maximum expression of the ure genes occurred under nitrogen-limiting conditions (e.g., serine or urea as the sole nitrogen source), but ure gene expression was not substrate (urea) inducible. Expression of the ure genes was strictly dependent on NtrC, whereas ς54 was not essential for urease activity. Expression of the ure genes was lower (by a factor of 3.5) in the presence of ammonium than under nitrogen-limiting conditions, but significant transcription was also observed in the presence of ammonium, approximately 10-fold higher than in an ntrC mutant background. Thus, ure gene expression in the presence of ammonium also requires NtrC. Footprint analyses demonstrated binding of NtrC to tandem binding sites upstream of the ureD promoter. Phosphorylation of NtrC increased DNA binding by at least eightfold. Although urea is effectively used as a nitrogen source in an NtrC-dependent manner, nitrogenase activity was not repressed by urea. PMID:11133958

  16. Microbial Iron(II) Oxidation in Littoral Freshwater Lake Sediment: The Potential for Competition between Phototrophic vs. Nitrate-Reducing Iron(II)-Oxidizers

    PubMed Central

    Melton, E. D.; Schmidt, C.; Kappler, A.

    2012-01-01

    The distribution of neutrophilic microbial iron oxidation is mainly determined by local gradients of oxygen, light, nitrate and ferrous iron. In the anoxic top part of littoral freshwater lake sediment, nitrate-reducing and phototrophic Fe(II)-oxidizers compete for the same e− donor; reduced iron. It is not yet understood how these microbes co-exist in the sediment and what role they play in the Fe cycle. We show that both metabolic types of anaerobic Fe(II)-oxidizing microorganisms are present in the same sediment layer directly beneath the oxic-anoxic sediment interface. The photoferrotrophic most probable number counted 3.4·105 cells·g−1 and the autotrophic and mixotrophic nitrate-reducing Fe(II)-oxidizers totaled 1.8·104 and 4.5·104 cells·g−1 dry weight sediment, respectively. To distinguish between the two microbial Fe(II) oxidation processes and assess their individual contribution to the sedimentary Fe cycle, littoral lake sediment was incubated in microcosm experiments. Nitrate-reducing Fe(II)-oxidizing bacteria exhibited a higher maximum Fe(II) oxidation rate per cell, in both pure cultures and microcosms, than photoferrotrophs. In microcosms, photoferrotrophs instantly started oxidizing Fe(II), whilst nitrate-reducing Fe(II)-oxidizers showed a significant lag-phase during which they probably use organics as e− donor before initiating Fe(II) oxidation. This suggests that they will be outcompeted by phototrophic Fe(II)-oxidizers during optimal light conditions; as phototrophs deplete Fe(II) before nitrate-reducing Fe(II)-oxidizers start Fe(II) oxidation. Thus, the co-existence of the two anaerobic Fe(II)-oxidizers may be possible due to a niche space separation in time by the day-night cycle, where nitrate-reducing Fe(II)-oxidizers oxidize Fe(II) during darkness and phototrophs play a dominant role in Fe(II) oxidation during daylight. Furthermore, metabolic flexibility of Fe(II)-oxidizing microbes may play a paramount role in the

  17. The emission of volatile compounds during the aerobic and the combined anaerobic/aerobic composting of biowaste

    NASA Astrophysics Data System (ADS)

    Smet, Erik; Van Langenhove, Herman; De Bo, Inge

    Two different biowaste composting techniques were compared with regard to their overall emission of volatile compounds during the active composting period. In the aerobic composting process, the biowaste was aerated during a 12-week period, while the combined anaerobic/aerobic composting process consisted of a sequence of a 3-week anaerobic digestion (phase I) and a 2-week aeration period (phase II). While the emission of volatiles during phase I of the combined anaerobic/aerobic composting process was measured in a full-scale composting plant, the aerobic stages of both composting techniques were performed in pilot-scale composting bins. Similar groups of volatile compounds were analysed in the biogas and the aerobic composting waste gases, being alcohols, carbonyl compounds, terpenes, esters, sulphur compounds and ethers. Predominance of alcohols (38% wt/wt of the cumulative emission) was observed in the exhaust air of the aerobic composting process, while predominance of terpenes (87%) and ammonia (93%) was observed in phases I and II of the combined anaerobic/aerobic composting process, respectively. In the aerobic composting process, 2-propanol, ethanol, acetone, limonene and ethyl acetate made up about 82% of the total volatile organic compounds (VOC)-emission. Next to this, the gas analysis during the aerobic composting process revealed a strong difference in emission profile as a function of time between different groups of volatiles. The total emission of VOC, NH 3 and H 2S during the aerobic composting process was 742 g ton -1 biowaste, while the total emission during phases I and II of the combined anaerobic/aerobic composting process was 236 and 44 g ton -1 biowaste, respectively. Taking into consideration the 99% removal efficiency of volatiles upon combustion of the biogas of phase I in the electricity generator, the combined anaerobic/aerobic composting process can be considered as an attractive alternative for aerobic biowaste composting because of

  18. The aerobic and anaerobic bacteriology of perirectal abscesses.

    PubMed Central

    Brook, I; Frazier, E H

    1997-01-01

    The microbiology of perirectal abscesses in 144 patients was studied. Aerobic or facultative bacteria only were isolated in 13 (9%) instances, anaerobic bacteria only were isolated in 27 (19%) instances, and mixed aerobic and anaerobic flora were isolated in 104 (72%) instances. A total of 325 anaerobic and 131 aerobic or facultative isolates were recovered (2.2 anaerobic isolates and 0.9 aerobic isolates per specimen). The predominant anaerobes were as follows: Bacteroides fragilis group (85 isolates), Peptostreptococcus spp. (72 isolates), Prevotella spp. (71 isolates), Fusobacterium spp. (21 isolates), Porphyromonas spp. (20 isolates), and Clostridium spp. (15 isolates). The predominant aerobic and facultative bacteria were as follows: Staphylococcus aureus (34 isolates), Streptococcus spp. (28 isolates), and Escherichia coli (19 isolates). These data illustrate the polymicrobial aerobic and anaerobic microbiology of perirectal abscesses. PMID:9350771

  19. Sequence-Based Identification of Aerobic Actinomycetes

    PubMed Central

    Patel, Jean Baldus; Wallace, Richard J.; Brown-Elliott, Barbara A.; Taylor, Tony; Imperatrice, Carol; Leonard, Deborah G. B.; Wilson, Rebecca W.; Mann, Linda; Jost, Kenneth C.; Nachamkin, Irving

    2004-01-01

    We investigated the utility of 500-bp 16S rRNA gene sequencing for identifying clinically significant species of aerobic actinomycetes. A total of 28 reference strains and 71 clinical isolates that included members of the genera Streptomyces, Gordonia, and Tsukamurella and 10 taxa of Nocardia were studied. Methods of nonsequencing analyses included growth and biochemical analysis, PCR-restriction enzyme analysis of the 439-bp Telenti fragment of the 65 hsp gene, susceptibility testing, and, for selected isolates, high-performance liquid chromatography. Many of the isolates were included in prior taxonomic studies. Sequencing of Nocardia species revealed that members of the group were generally most closely related to the American Type Culture Collection (ATCC) type strains. However, the sequences of Nocardia transvalensis, N. otitidiscaviarum, and N. nova isolates were highly variable; and it is likely that each of these species contains multiple species. We propose that these three species be designated complexes until they are more taxonomically defined. The sequences of several taxa did not match any recognized species. Among other aerobic actinomycetes, each group most closely resembled the associated reference strain, but with some divergence. The study demonstrates the ability of partial 16S rRNA gene sequencing to identify members of the aerobic actinomycetes, but the study also shows that a high degree of sequence divergence exists within many species and that many taxa within the Nocardia spp. are unnamed at present. A major unresolved issue is the type strain of N. asteroides, as the present one (ATCC 19247), chosen before the availability of molecular analysis, does not represent any of the common taxa associated with clinical nocardiosis. PMID:15184431

  20. Aerobic degradation of olive mill wastewaters.

    PubMed

    Benitez, J; Beltran-Heredia, J; Torregrosa, J; Acero, J L; Cercas, V

    1997-02-01

    The degradation of olive mill wastewater by aerobic microorganisms has been investigated in a batch reactor, by conducting experiments where the initial concentration of organic matter, quantified by the chemical oxygen demand, and the initial biomass were varied. The evolution of the chemical oxygen demand, biomass and the total contents of phenolic and aromatic compounds were followed through each experiment. According to the Contois model, a kinetic expression for the substrate utilization rate is derived, and its biokinetic constants are evaluated. This final predicted equation agrees well with all the experimental data. PMID:9077005

  1. [Heterotrophic Nitrification and Aerobic Denitrification of the Hypothermia Aerobic Denitrification Bacterium: Arthrobacter arilaitensis].

    PubMed

    He, Teng-xia; Ni, Jiu-pai; Li, Zhen-lun; Sun, Quan; Ye Qing; Xu, Yi

    2016-03-15

    High concentrations of ammonium, nitrate and nitrite nitrogen were employed to clarify the abilities of heterotrophic nitrification and aerobic denitrification of Arthrobacter arilaitensis strain Y-10. Meanwhile, by means of inoculating the strain suspension into the mixed ammonium and nitrate, ammonium and nitrite nitrogen simulated wastewater, we studied the simultaneous nitrification and denitrification ability of Arthrobacter arilaitensis strain Y-10. In addition, cell optical density was assayed in each nitrogen removal process to analyze the relationship of cell growth and nitrogen removal efficiency. The results showed that the hypothermia denitrification strain Arthrobacter arilaitensis Y-10 exhibited high nitrogen removal efficiency during heterotrophic nitrification and aerobic denitrification. The ammonium, nitrate and nitrite removal rates were 65.0%, 100% and 61.2% respectively when strain Y-10 was cultivated for 4 d at 15°C with initial ammonium, nitrate and nitrite nitrogen concentrations of 208.43 mg · L⁻¹, 201.16 mg · L⁻¹ and 194.33 mg · L⁻¹ and initial pH of 7.2. Nitrite nitrogen could only be accumulated in the medium containing nitrate nitrogen during heterotrophic nitrification and aerobic denitrification process. Additionally, the ammonium nitrogen was mainly removed in the inorganic nitrogen mixed synthetic wastewater. In short, Arthrobacter arilaitensis Y-10 could conduct nitrification and denitrification effectively under aerobic condition and the ammonium nitrogen removal rate was more than 80.0% in the inorganic nitrogen mixed synthetic wastewater. PMID:27337904

  2. Acute effects of aerobic exercise promote learning.

    PubMed

    Perini, Renza; Bortoletto, Marta; Capogrosso, Michela; Fertonani, Anna; Miniussi, Carlo

    2016-01-01

    The benefits that physical exercise confers on cardiovascular health are well known, whereas the notion that physical exercise can also improve cognitive performance has only recently begun to be explored and has thus far yielded only controversial results. In the present study, we used a sample of young male subjects to test the effects that a single bout of aerobic exercise has on learning. Two tasks were run: the first was an orientation discrimination task involving the primary visual cortex, and the second was a simple thumb abduction motor task that relies on the primary motor cortex. Forty-four and forty volunteers participated in the first and second experiments, respectively. We found that a single bout of aerobic exercise can significantly facilitate learning mechanisms within visual and motor domains and that these positive effects can persist for at least 30 minutes following exercise. This finding suggests that physical activity, at least of moderate intensity, might promote brain plasticity. By combining physical activity-induced plasticity with specific cognitive training-induced plasticity, we favour a gradual up-regulation of a functional network due to a steady increase in synaptic strength, promoting associative Hebbian-like plasticity. PMID:27146330

  3. Characterization and aerobic biodegradation of selected monoterpenes

    SciTech Connect

    Misra, G.; Pavlostathis, S.G.; Li, J.; Purdue, E.M.

    1996-12-31

    Monoterpenes are biogenic chemicals and occur in abundance in nature. Large-scale industrial use of these chemicals has recently been initiated in an attempt to replace halogenated solvents and chlorofluorocarbons which have been implicated in the stratospheric depletion of ozone. This study examined four hydrocarbon monoterpenes (d-limonene, {alpha}-pinene, {gamma}-terpinene, and terpinolene) and four alcohols (arbanol, linalool, plinol, and {alpha}-terpineol). Water solubility, vapor pressure, and octanol/water partition coefficients were estimated. Aerobic biodegradability tests were conducted in batch reactors by utilizing forest soil extract and enriched cultures as inoculum. The hydrophobic nature and high volatility of the hydrocarbons restricted the investigation to relatively low aqueous concentrations. Each monoterpene was analyzed with a gas chromatograph equipped with a flame ionization detector after extraction from the aqueous phase with isooctane. Terpene mineralization was tested by monitoring liquid-phase carbon, CO{sub 2} production and biomass growth. All four hydrocarbons and two alcohols readily degraded under aerobic conditions. Plinol resisted degradation in assays using inocula from diverse sources, while arbanol degraded very slowly. The intrinsic biokinetics coefficients for the degradation of d-limonene and {alpha}-terpineol were estimated by using cultures enriched with the respective monoterpenes. Monoterpene biodegradation followed Monod kinetics.

  4. Acute effects of aerobic exercise promote learning

    PubMed Central

    Perini, Renza; Bortoletto, Marta; Capogrosso, Michela; Fertonani, Anna; Miniussi, Carlo

    2016-01-01

    The benefits that physical exercise confers on cardiovascular health are well known, whereas the notion that physical exercise can also improve cognitive performance has only recently begun to be explored and has thus far yielded only controversial results. In the present study, we used a sample of young male subjects to test the effects that a single bout of aerobic exercise has on learning. Two tasks were run: the first was an orientation discrimination task involving the primary visual cortex, and the second was a simple thumb abduction motor task that relies on the primary motor cortex. Forty-four and forty volunteers participated in the first and second experiments, respectively. We found that a single bout of aerobic exercise can significantly facilitate learning mechanisms within visual and motor domains and that these positive effects can persist for at least 30 minutes following exercise. This finding suggests that physical activity, at least of moderate intensity, might promote brain plasticity. By combining physical activity–induced plasticity with specific cognitive training–induced plasticity, we favour a gradual up-regulation of a functional network due to a steady increase in synaptic strength, promoting associative Hebbian-like plasticity. PMID:27146330

  5. The Acute Effect of Aerobic Exercise on Measures of Stress.

    ERIC Educational Resources Information Center

    Fort, Inza L.; And Others

    The immediate response of stress to aerobic exercise was measured by utilizing the Palmar Sweat Index (PSI) and the State-Trait Anxiety Inventory (STAI). Forty subjects (20 male and 20 female) from the ages of 18-30 sustained a single bout of aerobic activity for 30 minutes at 60 percent of their maximum heart rate. Pre-treatment procedures…

  6. Psychological Benefits of Aerobic Running: Implications for Mental Health Counselors.

    ERIC Educational Resources Information Center

    Hinkle, J. Scott

    1988-01-01

    Discusses the effect of aerobic running on psychological functioning and its adjunctive use in mental health counseling. Concludes that mental health counselors can provide more comprehensive services if they expand the psychoeducational model to include physiological parameters such as aerobic running that are associated with optimum mental…

  7. The Psychology, Physiology, and Creativity of Middle School Aerobic Exercisers.

    ERIC Educational Resources Information Center

    Hinkle, J. Scott; And Others

    1993-01-01

    Investigated effects of aerobic running program on psychological and physical fitness and creative abilities of eight-grade school children. Students (n=85) were randomly assigned to aerobic running treatment groups or to control groups who participated in traditional, nonaerobic physical education. Found statistically significant increases for…

  8. Aerobic Fitness Thresholds Associated with Fifth Grade Academic Achievement

    ERIC Educational Resources Information Center

    Wittberg, Richard; Cottrell, Lesley A.; Davis, Catherine L.; Northrup, Karen L.

    2010-01-01

    Background: Whereas effects of physical fitness and physical activity on cognitive function have been documented, little is known about how they are related. Purpose: This study assessed student aerobic fitness measured by FITNESSGRAM Mile times and/or Pacer circuits and whether the nature of the association between aerobic fitness and…

  9. Factors associated with low levels of aerobic fitness among adolescents

    PubMed Central

    Gonçalves, Eliane Cristina de Andrade; Silva, Diego Augusto Santos

    2016-01-01

    Abstract Objective: To evaluate the prevalence of low aerobic fitness levels and to analyze the association with sociodemographic factors, lifestyle and excess body fatness among adolescents of southern Brazil. Methods: The study included 879 adolescents aged 14-19 years the city of São José/SC, Brazil. The aerobic fitness was assessed by Canadian modified test of aerobic fitness. Sociodemographic variables (skin color, age, sex, study turn, economic level), sexual maturation and lifestyle (eating habits, screen time, physical activity, consumption of alcohol and tobacco) were assessed by a self-administered questionnaire. Excess body fatness was evaluated by sum of skinfolds triceps and subscapular. We used logistic regression to estimate odds ratios and 95% confidence intervals. Results: Prevalence of low aerobic fitness level was 87.5%. The girls who spent two hours or more in front screen, consumed less than one glass of milk by day, did not smoke and had an excess of body fatness had a higher chance of having lower levels of aerobic fitness. White boys with low physical activity had had a higher chance of having lower levels of aerobic fitness. Conclusions: Eight out of ten adolescents were with low fitness levels aerobic. Modifiable lifestyle factors were associated with low levels of aerobic fitness. Interventions that emphasize behavior change are needed. PMID:26743851

  10. Aerobic Digestion. Student Manual. Biological Treatment Process Control.

    ERIC Educational Resources Information Center

    Klopping, Paul H.

    This manual contains the textual material for a single-lesson unit on aerobic sludge digestion. Topic areas addressed include: (1) theory of aerobic digestion; (2) system components; (3) performance factors; (4) indicators of stable operation; and (5) operational problems and their solutions. A list of objectives, glossary of key terms, and…

  11. EFFECTS OF CORN SILAGE INOCULANTS ON AEROBIC STABILITY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aerobic stability of corn silage can be a major problem for farmers particularly in warm weather. Silage inoculants, while the most common type of silage additive, have not been consistently effective at improving aerobic stability. This study investigated new and proposed inoculant products over ...

  12. Aerobic Activity--Do Physical Education Programs Provide Enough?

    ERIC Educational Resources Information Center

    McGing, Eileen

    1989-01-01

    High school physical education curricula should concentrate less on sport skill development and competition, and more on health-related fitness and aerobic activity. Results are reported from a study of the type and amount of aerobic exercise provided in 29 high school physical education programs in a large metropolitan area. (IAH)

  13. Sexual dimorphism in primate aerobic capacity: a phylogenetic test.

    PubMed

    Lindenfors, Patrik; Revell, L J; Nunn, C L

    2010-06-01

    Male intrasexual competition should favour increased male physical prowess. This should in turn result in greater aerobic capacity in males than in females (i.e. sexual dimorphism) and a correlation between sexual dimorphism in aerobic capacity and the strength of sexual selection among species. However, physiological scaling laws predict that aerobic capacity should be lower per unit body mass in larger than in smaller animals, potentially reducing or reversing the sex difference and its association with measures of sexual selection. We used measures of haematocrit and red blood cell (RBC) counts from 45 species of primates to test four predictions related to sexual selection and body mass: (i) on average, males should have higher aerobic capacity than females, (ii) aerobic capacity should be higher in adult than juvenile males, (iii) aerobic capacity should increase with increasing sexual selection, but also that (iv) measures of aerobic capacity should co-vary negatively with body mass. For the first two predictions, we used a phylogenetic paired t-test developed for this study. We found support for predictions (i) and (ii). For prediction (iii), however, we found a negative correlation between the degree of sexual selection and aerobic capacity, which was opposite to our prediction. Prediction (iv) was generally supported. We also investigated whether substrate use, basal metabolic rate and agility influenced physiological measures of oxygen transport, but we found only weak evidence for a correlation between RBC count and agility. PMID:20406346

  14. 40 CFR 796.3100 - Aerobic aquatic biodegradation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 32 2014-07-01 2014-07-01 false Aerobic aquatic biodegradation. 796.3100 Section 796.3100 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT (CONTINUED) CHEMICAL FATE TESTING GUIDELINES Transformation Processes § 796.3100 Aerobic aquatic biodegradation. (a)...

  15. 40 CFR 796.3100 - Aerobic aquatic biodegradation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 33 2012-07-01 2012-07-01 false Aerobic aquatic biodegradation. 796.3100 Section 796.3100 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT (CONTINUED) CHEMICAL FATE TESTING GUIDELINES Transformation Processes § 796.3100 Aerobic aquatic biodegradation. (a)...

  16. 40 CFR 796.3100 - Aerobic aquatic biodegradation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 32 2011-07-01 2011-07-01 false Aerobic aquatic biodegradation. 796.3100 Section 796.3100 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT (CONTINUED) CHEMICAL FATE TESTING GUIDELINES Transformation Processes § 796.3100 Aerobic aquatic biodegradation. (a)...

  17. Heart rate during aerobics classes in women with different previous experience of aerobics.

    PubMed

    Laukkanen, R M; Kalaja, M K; Kalaja, S P; Holmala, E B; Paavolainen, L M; Tummavuori, M; Virtanen, P; Rusko, H K

    2001-01-01

    This study measured heart rate during floor and step aerobic classes at three intensity levels. A group of 20 female occasional exercisers [mean age 33 (SD 8) years, mean body mass index 21 (SD 2) kg.m-2 volunteered to participate in six aerobic classes (three floor classes, three step classes) and in a laboratory test as members of one of two groups according to their prestudy regular participation in aerobics classes. Subjects in group A had participated four or more times a week and those of group B less than twice a week. The characteristics of the groups were as follows: group A, n = 10, mean maximal oxygen uptake (VO2max) 38.7 (SD 3.6) ml.kg-1.min-1, mean maximal heart rate (HRmax) 183 (SD 8) beats.min-1; group B, n = 10, VO2max 36.1 (SD 3.6) ml.kg-1.min-1, HRmax 178 (SD 7) beats.min-1. Each class consisted of a warm-up, a 20 min period of structured aerobic exercise (cardiophase) and a cool-down. The cardiophase was planned and guided as light, (rate of perceived exertion, RPE 11-12), moderate (RPE 13-14) or heavy (RPE 15-17) by an experienced instructor. The mean heart rates during the light classes were 72 (step) and 74 (floor) %HRmax in group A and 75 (step) and 79 (floor) %HRmax in group B; during the moderate classes, 84 (step) and 80 (floor) %HRmax in group A and 82 (step) and 83 (floor) %HRmax in group B, and during the heavy classes 89 (step and floor) %HRmax in group A and 88 (step) and 92 (floor) %HRmax in group B. Differences in heart rate and %HRmax were not statistically significant between the groups. However, differences in heart rate and %HRmax between the intensities (light vs moderate, moderate vs heavy and light vs heavy) were significant within both groups (all, P < 0.01). Based on the results, we conclude that intensity management during the aerobics classes was generally successful regardless of the participants' prior participation in aerobics. However, some individuals who were older and/or had less prior participation tended to

  18. Production possibility frontiers in phototroph:heterotroph symbioses: trade-offs in allocating fixed carbon pools and the challenges these alternatives present for understanding the acquisition of intracellular habitats

    PubMed Central

    Hill, Malcolm S.

    2014-01-01

    Intracellular habitats have been invaded by a remarkable diversity of organisms, and strategies employed to successfully reside in another species' cellular space are varied. Common selective pressures may be experienced in symbioses involving phototrophic symbionts and heterotrophic hosts. Here I refine and elaborate the Arrested Phagosome Hypothesis that proposes a mechanism that phototrophs use to gain access to their host's intracellular habitat. I employ the economic concept of production possibility frontiers (PPF) as a useful heuristic to clearly define the trade-offs that an intracellular phototroph is likely to face as it allocates photosynthetically-derived pools of energy. Fixed carbon can fuel basic metabolism/respiration, it can support mitotic division, or it can be translocated to the host. Excess photosynthate can be stored for future use. Thus, gross photosynthetic productivity can be divided among these four general categories, and natural selection will favor phenotypes that best match the demands presented to the symbiont by the host cellular habitat. The PPF highlights trade-offs that exist between investment in growth (i.e., mitosis) or residency (i.e., translocating material to the host). Insights gained from this perspective might help explain phenomena such as coral bleaching because deficits in photosynthetic production are likely to diminish a symbiont's ability to “afford” the costs of intracellular residency. I highlight deficits in our current understanding of host:symbiont interactions at the molecular, genetic, and cellular level, and I also discuss how semantic differences among scientists working with different symbiont systems may diminish the rate of increase in our understanding of phototrophic-based associations. I argue that adopting interdisciplinary (in this case, inter-symbiont-system) perspectives will lead to advances in our general understanding of the phototrophic symbiont's intracellular niche. PMID:25101064

  19. Brain aerobic glycolysis and motor adaptation learning

    PubMed Central

    Shannon, Benjamin J.; Vaishnavi, Sanjeev Neil; Vlassenko, Andrei G.; Shimony, Joshua S.; Rutlin, Jerrel; Raichle, Marcus E.

    2016-01-01

    Ten percent to 15% of glucose used by the brain is metabolized nonoxidatively despite adequate tissue oxygenation, a process termed aerobic glycolysis (AG). Because of the known role of glycolysis in biosynthesis, we tested whether learning-induced synaptic plasticity would lead to regionally appropriate, learning-dependent changes in AG. Functional MRI (fMRI) before, during, and after performance of a visual–motor adaptation task demonstrated that left Brodmann area 44 (BA44) played a key role in adaptation, with learning-related changes to activity during the task and altered resting-state, functional connectivity after the task. PET scans before and after task performance indicated a sustained increase in AG in left BA 44 accompanied by decreased oxygen consumption. Intersubject variability in behavioral adaptation rate correlated strongly with changes in AG in this region, as well as functional connectivity, which is consistent with a role for AG in synaptic plasticity. PMID:27217563

  20. Surface Structure of Aerobically Oxidized Diamond Nanocrystals

    PubMed Central

    2015-01-01

    We investigate the aerobic oxidation of high-pressure, high-temperature nanodiamonds (5–50 nm dimensions) using a combination of carbon and oxygen K-edge X-ray absorption, wavelength-dependent X-ray photoelectron, and vibrational spectroscopies. Oxidation at 575 °C for 2 h eliminates graphitic carbon contamination (>98%) and produces nanocrystals with hydroxyl functionalized surfaces as well as a minor component (<5%) of carboxylic anhydrides. The low graphitic carbon content and the high crystallinity of HPHT are evident from Raman spectra acquired using visible wavelength excitation (λexcit = 633 nm) as well as carbon K-edge X-ray absorption spectra where the signature of a core–hole exciton is observed. Both spectroscopic features are similar to those of chemical vapor deposited (CVD) diamond but differ significantly from the spectra of detonation nanodiamond. The importance of these findings to the functionalization of nanodiamond surfaces for biological labeling applications is discussed. PMID:25436035

  1. Aerobic Microbial Degradation of Glucoisosaccharinic Acid

    PubMed Central

    Strand, S. E.; Dykes, J.; Chiang, V.

    1984-01-01

    α-Glucoisosaccharinic acid (GISA), a major by-product of kraft paper manufacture, was synthesized from lactose and used as the carbon source for microbial media. Ten strains of aerobic bacteria capable of growth on GISA were isolated from kraft pulp mill environments. The highest growth yields were obtained with Ancylobacter spp. at pH 7.2 to 9.5. GISA was completely degraded by cultures of an Ancylobacter isolate. Ancylobacter cell suspensions consumed oxygen and produced carbon dioxide in response to GISA addition. A total of 22 laboratory strains of bacteria were tested, and none was capable of growth on GISA. GISA-degrading isolates were not found in forest soils. Images PMID:16346467

  2. Brain aerobic glycolysis and motor adaptation learning.

    PubMed

    Shannon, Benjamin J; Vaishnavi, Sanjeev Neil; Vlassenko, Andrei G; Shimony, Joshua S; Rutlin, Jerrel; Raichle, Marcus E

    2016-06-28

    Ten percent to 15% of glucose used by the brain is metabolized nonoxidatively despite adequate tissue oxygenation, a process termed aerobic glycolysis (AG). Because of the known role of glycolysis in biosynthesis, we tested whether learning-induced synaptic plasticity would lead to regionally appropriate, learning-dependent changes in AG. Functional MRI (fMRI) before, during, and after performance of a visual-motor adaptation task demonstrated that left Brodmann area 44 (BA44) played a key role in adaptation, with learning-related changes to activity during the task and altered resting-state, functional connectivity after the task. PET scans before and after task performance indicated a sustained increase in AG in left BA 44 accompanied by decreased oxygen consumption. Intersubject variability in behavioral adaptation rate correlated strongly with changes in AG in this region, as well as functional connectivity, which is consistent with a role for AG in synaptic plasticity. PMID:27217563

  3. New Routes for Aerobic Biodegradation of Dimethylsulfoniopropionate

    PubMed Central

    Taylor, Barrie F.; Gilchrist, Darrin C.

    1991-01-01

    Dimethylsulfoniopropionate (DMSP), an osmolyte in marine plants, is biodegraded by cleavage of dimethyl sulfide (DMS) or by demethylation to 3-methiolpropionate (MMPA) and 3-mercaptopropionate (MPA). Sequential demethylation has been observed only with anoxic slurries of coastal sediments. Bacteria that grew aerobically on MMPA and DMSP were isolated from marine environments and phytoplankton cultures. Enrichments with DMSP selected for bacteria that generated DMS, whereas MMPA enrichments selected organisms that produced methanethiol (CH3SH) from either DMSP or MMPA. A bacterium isolated on MMPA grew on MMPA and DMSP, but rapid production of CH3SH from DMSP occurred only with DMSP-grown cells. Low levels of MPA accumulated during growth on MMPA, indicating demethylation as well as demethiolation of MMPA. The alternative routes for DMSP biodegradation via MMPA probably impact on net DMS fluxes to the marine atmosphere. PMID:16348607

  4. Biology of Moderately Halophilic Aerobic Bacteria

    PubMed Central

    Ventosa, Antonio; Nieto, Joaquín J.; Oren, Aharon

    1998-01-01

    The moderately halophilic heterotrophic aerobic bacteria form a diverse group of microorganisms. The property of halophilism is widespread within the bacterial domain. Bacterial halophiles are abundant in environments such as salt lakes, saline soils, and salted food products. Most species keep their intracellular ionic concentrations at low levels while synthesizing or accumulating organic solutes to provide osmotic equilibrium of the cytoplasm with the surrounding medium. Complex mechanisms of adjustment of the intracellular environments and the properties of the cytoplasmic membrane enable rapid adaptation to changes in the salt concentration of the environment. Approaches to the study of genetic processes have recently been developed for several moderate halophiles, opening the way toward an understanding of haloadaptation at the molecular level. The new information obtained is also expected to contribute to the development of novel biotechnological uses for these organisms. PMID:9618450

  5. [Research of aerobic granule characteristics with different granule age].

    PubMed

    Zhou, Man; Yang, Chang-Zhu; Pu, Wen-Hong; Luo, Ying-Dong; Gong, Jian-Yu

    2012-03-01

    In the SBR reactor, we studied the different style, physicochemical characteristic, pollutants removal and microbial activity between the short age and long age aerobic granule, respectively. The short age aerobic granule was cultivated from activated floccules sludge and the other was gotten from aerobic granular sludge which was operated stably more than one year. The results indicated that the wet density, the specific gravity and integrated coefficient (IC) of the short age aerobic granule were 1.066 g x cm(-1), 1.013 g x cm(-3) and 98.7%, respectively. And that of long age were 1.026 g x cm(-3), 1.010 g x cm(-3) and 98.4%, respectively. All of them were higher than the long age aerobic granule. The mean diameters of them were 1.9 mm and 2.2 mm, respectively. The settling velocity of short age and long age aerobic granule were 0.005-0.032 m x s(-1) and 0.003-0.028 m x s(-1), respectively, and two kinds of aerobic granule settling velocity increased with the diameter increased. SVI of the former was lower. The COD removal rates of two aerobic granules were above 90%, and the NH4(+) -N removal rates of them were about 85%. The results of the COD effluent concentration, NH4(+) -N effluent concentration and the pollutants concentration in a typical cycle indicated that the short age aerobic granule had better pollutants removal efficiency. The TP removal rates of them were between 40% -90% and 32% -85%, respectively. The TN removal rates of them were about 80%. The SOUR(H) SOUR(NH4) and SOUR(NO2) of the short age aerobic granule were 26.4, 14.8 and 11.2 mg x (h x g)(-1), respectively. And that of long age were 25.2, 14.4 and 8.4 mg x (h x g)(-1), respectively. In summary, the aerobic granule had significantly different physical and chemical characteristics because of different granule age, and the short age aerobic granule exhibited better pollutants removal ability, higher microbial activity and more stability than the long age aerobic granule. PMID:22624385

  6. Effects of Kettlebell Training on Aerobic Capacity.

    PubMed

    Falatic, J Asher; Plato, Peggy A; Holder, Christopher; Finch, Daryl; Han, Kyungmo; Cisar, Craig J

    2015-07-01

    This study examined the effects of a kettlebell training program on aerobic capacity. Seventeen female National Collegiate Athletic Association Division I collegiate soccer players (age: 19.7 ± 1.0 years, height: 166.1 ± 6.4 cm, weight: 64.2 ± 8.2 kg) completed a graded exercise test to determine maximal oxygen consumption (V̇O2max). Participants were assigned to a kettlebell intervention group (KB) (n = 9) or a circuit weight-training (CWT) control group (n = 8). Participants in the KB group completed a kettlebell snatch test to determine individual snatch repetitions. Both groups trained 3 days a week for 4 weeks in addition to their off-season strength and conditioning program. The KB group performed the 15:15 MVO2 protocol (20 minutes of kettlebell snatching with 15 seconds of work and rest intervals). The CWT group performed multiple free-weight and dynamic body-weight exercises as part of a continuous circuit program for 20 minutes. The 15:15 MVO2 protocol significantly increased V̇O2max in the KB group. The average increase was 2.3 ml·kg⁻¹·min⁻¹, or approximately a 6% gain. There was no significant change in V̇O2max in the CWT control group. Thus, the 4-week 15:15 MVO2 kettlebell protocol, using high-intensity kettlebell snatches, significantly improved aerobic capacity in female intercollegiate soccer players and could be used as an alternative mode to maintain or improve cardiovascular conditioning. PMID:26102260

  7. Microbial composition and ecological features of phototrophic biofilms proliferating in the Moidons Caves (France): investigation at the single-cell level.

    PubMed

    Borderie, Fabien; Denis, Michel; Barani, Aude; Alaoui-Sossé, Badr; Aleya, Lotfi

    2016-06-01

    The authors investigated the microbial composition of phototrophic biofilms proliferating in a show cave using flow cytometry for the first time in such a context. Results are based on several biofilms sampled in the Moidons Caves (France) and concern both heterotrophic prokaryotes and autotrophic microorganisms. Heterotrophic microorganisms with low nucleic acid content were dominant in biofilms, as can be expected from the oligotrophic conditions prevailing within the cave. Analysis of the biofilm autotrophic components revealed the presence of several taxa, particularly the unicellular green algae Chlorella minutissima, specifically well adapted to this cave. Relationships between flow cytometry results and environmental variables determined in the cave were established and discussed so as to better understand biofilm proliferation processes in caves. PMID:26961535

  8. Sequential anaerobic/aerobic biotreatment of bark leachate.

    PubMed

    Frigon, J C; Cimpoia, R; Guiot, S R

    2003-01-01

    Bark leachate is generated from sawmill operations such as log storage sites and contains polymeric tannins, carbohydrates, organic acids, phenolic and resin compounds. The present study was aimed at assessing the performance of a sequential anaerobic and aerobic treatment, for both chemical oxygen demand (COD) and phenol removal, under various combinations of operational conditions, in the continuous mode. After anaerobic treatment in a five litres upflow anaerobic sludge bed (UASB) reactor, the leachate was directed into two parallel aerobic reactors, either an activated sludge unit or a fixed film submerged filter (packed with polyethylene Flexirings), both of a volume of one litre and oxygenated by air diffusion. For a leachate of 22 gCOD/l, an overall COD removal of 96-98% was achieved at an hydraulic residence time (HRT) of 4 days for the anaerobic reactor and one day for either aerobic systems. The phenol concentration generally increased after anaerobic treatment but was below the detection limit (50 ppb) after aerobic polishing. Radiorespirometric microcosms with 14C-labelled phenol confirmed that phenol was mineralized in the aerobic reactors. The performances of both aerobic systems were similar for COD and phenol removal. Thus, a sequential anaerobic/aerobic treatment was able to effectively address the contamination of a bark leachate discharge, including phenols. PMID:14640219

  9. Cardioprotective Properties of Aerobic and Resistance Training Against Myocardial Infarction.

    PubMed

    Barboza, C A; Souza, G I H; Oliveira, J C M F; Silva, L M; Mostarda, C T; Dourado, P M M; Oyama, L M; Lira, F S; Irigoyen, M C; Rodrigues, B

    2016-06-01

    We evaluated the effects of aerobic and resistance exercise training on ventricular morphometry and function, physical capacity, autonomic function, as well as on ventricular inflammatory status in trained rats prior to myocardial infarction. Male Wistar rats were divided into the following groups: sedentary+Sham, sedentary+myocardial infarction, aerobic trained+myocardial infarction, and resistance trained+myocardial infarction. Sham and myocardial infarction were performed after training periods. In the days following the surgeries, evaluations were performed. Aerobic training prevents aerobic (to a greater extent) and resistance capacity impairments, ventricular dysfunction, baroreflex sensitivity and autonomic disorders (vagal tonus decrease and sympathetic tonus increase) triggered by myocardial infarction. Resistance training was able to prevent negative changes to aerobic and resistance capacity (to a greater extent) but not to ventricular dysfunction, and it prevented cardiovascular sympathetic increments. Additionally, both types of training reduced left ventricle inflammatory cytokine concentration. Our results suggest that aerobic and, for the first time, dynamic resistance training were able to reduce sympathetic tonus to the heart and vessels, as well as preventing the increase in pro-inflammatory cytokine concentrations in the left ventricle of trained groups. These data emphasizes the positive effects of aerobic and dynamic resistance training on the prevention of the negative changes triggered by myocardial infarction. PMID:26928914

  10. Upper limb aerobic training improves aerobic fitness and all-out performance of America's Cup grinders.

    PubMed

    Adami, Paolo Emilio; Delussu, Anna Sofia; Rodio, Angelo; Squeo, Maria Rosaria; Corsi, Loretta; Quattrini, Filippo Maria; Fattorini, Luigi; Bernardi, Marco

    2015-01-01

    This research on "America's Cup" grinders investigated the effects of a specific eight-week long-arm cranking ergometer (ACE) training on upper body (UB) aerobic fitness (ventilatory threshold - Tvent, respiratory compensation point- RCP, -oxygen uptake peak - VO₂peak) and high intensity working capacity. The training consisted of sessions carried out for 20-30 mins, three times per week, at an intensity between the UB-Tvent and UB-RCP, and replaced part of a typical lower limb aerobic training whilst maintaining the usual weekly schedule of callisthenics, resistance training and sailing. Seven sailors, including four grinders and three mastmen (age 30 ± 5.5 years, height 1.9 ± 0.04 m, body mass 102 ± 3.6 kg), were evaluated through both an ACE cardiopulmonary maximal exercise test (CPET) and an ACE all-out up to exhaustion exercise test, before and after the ACE training. UB aerobic fitness improved significantly: UB-VO₂peak increased from 4.29 ± 0.442 to 4.52 ± 0.522 l·min(-1) (6.4 ± 3.66%), VO₂ at UB-Tvent from 2.42 ± 0.282 to 2.97 ± 0.328 l·min(-1) (22.8 ± 5.09%) and VO₂ at UB-RCP from 3.25 ± 0.402 to 3.75 ± 0.352 l·min(-1) (16.1 ± 10.83%). Peak power at the ACE CPET increased from 351 ± 27.5 to 387 ± 33.5 W (10.5 ± 6.93%). The all-out test total mechanical work increased from 28.9 ± 2.35 to 40.1 ± 3.76 kJ (72.1 ± 4.67%). In conclusion, a high intensity aerobic ACE training can be effective in improving grinding performance by increasing UB aerobic fitness and all-out working capacity. PMID:25357134

  11. Novel Genes of the dsr Gene Cluster and Evidence for Close Interaction of Dsr Proteins during Sulfur Oxidation in the Phototrophic Sulfur Bacterium Allochromatium vinosum

    PubMed Central

    Dahl, Christiane; Engels, Sabine; Pott-Sperling, Andrea S.; Schulte, Andrea; Sander, Johannes; Lübbe, Yvonne; Deuster, Oliver; Brune, Daniel C.

    2005-01-01

    Seven new genes designated dsrLJOPNSR were identified immediately downstream of dsrABEFHCMK, completing the dsr gene cluster of the phototrophic sulfur bacterium Allochromatium vinosum D (DSM 180T). Interposon mutagenesis proved an essential role of the encoded proteins for the oxidation of intracellular sulfur, an obligate intermediate during the oxidation of sulfide and thiosulfate. While dsrR and dsrS encode cytoplasmic proteins of unknown function, the other genes encode a predicted NADPH:acceptor oxidoreductase (DsrL), a triheme c-type cytochrome (DsrJ), a periplasmic iron-sulfur protein (DsrO), and an integral membrane protein (DsrP). DsrN resembles cobyrinic acid a,c-diamide synthases and is probably involved in the biosynthesis of siro(heme)amide, the prosthetic group of the dsrAB-encoded sulfite reductase. The presence of most predicted Dsr proteins in A. vinosum was verified by Western blot analysis. With the exception of the constitutively present DsrC, the formation of Dsr gene products was greatly enhanced by sulfide. DsrEFH were purified from the soluble fraction and constitute a soluble α2β2γ2-structured 75-kDa holoprotein. DsrKJO were purified from membranes pointing at the presence of a transmembrane electron-transporting complex consisting of DsrKMJOP. In accordance with the suggestion that related complexes from dissimilatory sulfate reducers transfer electrons to sulfite reductase, the A. vinosum Dsr complex is copurified with sulfite reductase, DsrEFH, and DsrC. We therefore now have an ideal and unique possibility to study the interaction of sulfite reductase with other proteins and to clarify the long-standing problem of electron transport from and to sulfite reductase, not only in phototrophic bacteria but also in sulfate-reducing prokaryotes. PMID:15687204

  12. Novel genes of the dsr gene cluster and evidence for close interaction of Dsr proteins during sulfur oxidation in the phototrophic sulfur bacterium Allochromatium vinosum.

    PubMed

    Dahl, Christiane; Engels, Sabine; Pott-Sperling, Andrea S; Schulte, Andrea; Sander, Johannes; Lübbe, Yvonne; Deuster, Oliver; Brune, Daniel C

    2005-02-01

    Seven new genes designated dsrLJOPNSR were identified immediately downstream of dsrABEFHCMK, completing the dsr gene cluster of the phototrophic sulfur bacterium Allochromatium vinosum D (DSM 180(T)). Interposon mutagenesis proved an essential role of the encoded proteins for the oxidation of intracellular sulfur, an obligate intermediate during the oxidation of sulfide and thiosulfate. While dsrR and dsrS encode cytoplasmic proteins of unknown function, the other genes encode a predicted NADPH:acceptor oxidoreductase (DsrL), a triheme c-type cytochrome (DsrJ), a periplasmic iron-sulfur protein (DsrO), and an integral membrane protein (DsrP). DsrN resembles cobyrinic acid a,c-diamide synthases and is probably involved in the biosynthesis of siro(heme)amide, the prosthetic group of the dsrAB-encoded sulfite reductase. The presence of most predicted Dsr proteins in A. vinosum was verified by Western blot analysis. With the exception of the constitutively present DsrC, the formation of Dsr gene products was greatly enhanced by sulfide. DsrEFH were purified from the soluble fraction and constitute a soluble alpha(2)beta(2)gamma(2)-structured 75-kDa holoprotein. DsrKJO were purified from membranes pointing at the presence of a transmembrane electron-transporting complex consisting of DsrKMJOP. In accordance with the suggestion that related complexes from dissimilatory sulfate reducers transfer electrons to sulfite reductase, the A. vinosum Dsr complex is copurified with sulfite reductase, DsrEFH, and DsrC. We therefore now have an ideal and unique possibility to study the interaction of sulfite reductase with other proteins and to clarify the long-standing problem of electron transport from and to sulfite reductase, not only in phototrophic bacteria but also in sulfate-reducing prokaryotes. PMID:15687204

  13. N-acetyl-L-glutamate kinase (NAGK) from oxygenic phototrophs: P(II) signal transduction across domains of life reveals novel insights in NAGK control.

    PubMed

    Beez, Sabine; Fokina, Oleksandra; Herrmann, Christina; Forchhammer, Karl

    2009-06-19

    N-Acetyl-L-glutamate kinase (NAGK) catalyzes the first committed step in arginine biosynthesis in organisms that perform the cyclic pathway of ornithine synthesis. In eukaryotic and bacterial oxygenic phototrophs, the activity of NAGK is controlled by the P(II) signal transduction protein. Recent X-ray analysis of NAGK-P(II) complexes from a higher plant (Arabidopsis thaliana) and a cyanobacterium (Synechococcus elongatus) revealed that despite several differences, the overall structure of the complex is highly similar. The present study analyzes the functional conservation of P(II)-mediated NAGK regulation in plants and cyanobacteria to distinguish between universal properties and those that are specific for the different phylogenetic lineages. This study shows that plant and cyanobacterial P(II) proteins can mutually regulate the NAGK enzymes across the domains of life, implying a high selective pressure to conserve P(II)-NAGK interaction over more than 1.2 billion years of separate evolution. The non-conserved C-terminus of S. elongatus NAGK was identified as an element, which strongly enhances arginine inhibition and is responsible for most of the differences between S. elongatus and A. thaliana NAGK with respect to arginine sensitivity. Both P(II) proteins relieve arginine inhibition of NAGK, and in both lineages, P(II)-mediated relief from arginine inhibition is antagonized by 2-oxoglutarate. Together, these properties highlight the conserved role of P(II) as a signal integrator of the C/N balance sensed as 2-oxoglutarate to regulate arginine synthesis in oxygenic phototrophs. PMID:19409905

  14. Anaerobic digestion of dairy cattle manure autoheated by aerobic pretreatment

    SciTech Connect

    Achkari-Begdouri, A.

    1989-01-01

    A novel way to heat anaerobic digesters was investigated. Dairy cattle manure was autoheated by an aerobic pretreatment process and then fed to the anaerobic digester. Important physical properties of the dairy cattle manure were determined. These included bulk density, specific heat, thermal conductivity and the rheological properties; consistency coefficient, behavior index and apparent viscosity. These parameters were used to calculate the overall heat transfer coefficients, and to estimate the heat losses from the aerobic reactor to the outside environment. The total energy balance of the aerobic treatment system was then established. An optimization study of the main parameters influencing the autoheating process showed that the total solids, the air flow rate and the stirring speed for operation of the aerobic pretreatment should be approximately 7%, 70 L/H and 1,400 rpm respectively. Temperatures as high as 65C were reached in 40 hours of aerobic treatment. At the above recommended levels of total solids, the air flow rate and the stirring speed, there was little difference in the energy requirements for heating the influent by aeration and heating the influent by a conventional heating system. In addition to the temperature increase, the aerobic pretreatment assisted in balancing the anaerobic digestion process and increased the methanogenesis of the dairy cattle manure. Despite the 8% decomposition of organic matter that occurred during the aerobic pretreatment process, methane production of the digester started with the aerobically heated manure was significantly higher (at least 20% higher) than of the digester started with conventionally heated manure. The aerobic system successfully autoheated the dairy cattle manure with an energy cost equal to that of conventionally heated influent.

  15. Aerobic Exercise Program Reduces Anger Expression Among Overweight Children

    PubMed Central

    Tkacz, Joseph; Young-Hyman, Deborah; Boyle, Colleen A.; Davis, Catherine L.

    2009-01-01

    This study tested the effect of a structured aerobic exercise program on anger expression in healthy overweight children. Overweight, sedentary children were randomly assigned to an aerobic exercise program or a no-exercise control condition. All children completed the Pediatric Anger Expression Scale at baseline and posttest. Anger Out and Anger Expression scores were lower for the exercise condition at posttest. Fitness improvements contributed significantly to final models, and points earned for adherence correlated negatively with posttest Anger Out. An aerobic exercise program might be an effective strategy to reduce anger expression, including reduction of aggressive behavior, in overweight children. PMID:19168916

  16. Considerations in prescribing preflight aerobic exercise for astronauts

    NASA Technical Reports Server (NTRS)

    Frey, Mary Anne Bassett

    1987-01-01

    The physiological effects of prolonged exposure to weightlessness are discussed together with the effects of aerobic exercise on human characteristics affected by weightlessness. It is noted that, although early data on orthostatic intolerance after spaceflight led to a belief that a high level of aerobic fitness for astronauts was detrimental to orthostatic tolerance on return to earth, most of the data available today do not suport this contention. Aerobic fitness was found to be beneficial to cardiovascular function and to mental performance; therefore, it may be important in performing extravehicular activities during flight.

  17. Evaluation of Biodegradability of Waste Before and After Aerobic Treatment

    NASA Astrophysics Data System (ADS)

    Suchowska-Kisielewicz, Monika; Jędrczak, Andrzej; Sadecka, Zofia

    2014-12-01

    An important advantage of use of an aerobic biostabilization of waste prior to its disposal is that it intensifies the decomposition of the organic fraction of waste into the form which is easily assimilable for methanogenic microorganisms involved in anaerobic decomposition of waste in the landfill. In this article it is presented the influence of aerobic pre-treatment of waste as well as leachate recirculation on susceptibility to biodegradation of waste in anaerobic laboratory reactors. The research has shown that in the reactor with aerobically treated waste stabilized with recilculation conversion of the organic carbon into the methane is about 45% higher than in the reactor with untreated waste stabilized without recirculation.

  18. Effects of a Rebound Exercise Training Program on Aerobic Capacity and Body Composition.

    ERIC Educational Resources Information Center

    Tomassoni, Teresa L.; And Others

    1985-01-01

    This study was designed to determine if aerobic dancing on rebound exercise equipment (minitrampolines) is an effective way to improve aerobic capacity and body composition. Although aerobic capacity improved, percent body fat did not change. Results were similar to those produced by conventional aerobic dance programs of like intensity. (MT)

  19. Issues of Health, Appearance and Physical Activity in Aerobic Classes for Women

    ERIC Educational Resources Information Center

    D'Abundo, Michelle Lee

    2009-01-01

    The purpose of this research was to explore what appearance-focused messages were conveyed by aerobic instructors in aerobic classes for women. This qualitative research was influenced by the concept of wellness and how feminist pedagogy can be applied to promote individuals' well-being in aerobic classes. The practices of five aerobic instructors…

  20. Characteristics of aerobic granulation at mesophilic temperatures in wastewater treatment.

    PubMed

    Cui, Fenghao; Park, Seyong; Kim, Moonil

    2014-01-01

    Compact and structurally stable aerobic granules were developed in a sequencing batch reactor (SBR) at mesophilic temperatures (35°C). The morphological, biological and chemical characteristics of the aerobic granulation were investigated and a theoretical granulation mechanism was proposed according to the results of the investigation. The mature aerobic granules had compact structure, small size (mean diameter of 0.24 mm), excellent settleability and diverse microbial structures, and were effective for the removal of organics and nitrification. The growth kinetics demonstrated that the biomass growth depended on coexistence and interactions between heterotrophs and autotrophs in the granules. The functions of heterotrophs and autotrophs created a compact and secure layer on the outside of the granules, protecting the inside sludge containing environmentally sensitive and slow growing microorganisms. The mechanism and the reactor performance may promise feasibility and efficiency for treating industry effluents at mesophilic temperatures using aerobic granulation. PMID:24211486

  1. Prediction of Maximum Aerobic Power in Untrained Females

    ERIC Educational Resources Information Center

    Dolgener, Forrest A.

    1978-01-01

    The author presents an equation for predicting maximum aerobic power in untrained females from values of percent body fat, weight, and submaximal values of heart rate, respiratory quotient, and expired gas. (MJB)

  2. Saline storage of aerobic granules and subsequent reactivation.

    PubMed

    Wan, Chunli; Lee, Duu-Jong; Yang, Xue; Wang, Yayi; Lin, Lin

    2014-11-01

    Loss of structural stability and bioactivity during long-term storage and operation is primary challenge to field applications of aerobic granular processes. This study for the first time stored aerobic granules in 5%w/w NaCl solution at 4°C for 187d. The stored granules were then successfully reactivated and used for 85d in sequencing batch reactors (SBR) and continuous-flow reactors (CFR) at varying levels of chemical oxygen demand (COD). High-throughput sequencing results reveal that Thauera sp., Paracoccus sp., and Nitrosomonas sp. were the predominant in the stored aerobic granules, and Pseudoxanthomonas sp. accumulated during the reactivation process. Saline storage, in which cells are in an unculturable state by saline stress, is a promising storage process for aerobic granules. PMID:25270079

  3. Aerobic capacity is correlated with the ranking of boxers.

    PubMed

    Bruzas, Vidas; Stasiulis, Arvydas; Cepulenas, Algirdas; Mockus, Pranas; Statkeviciene, Birute; Subacius, Vitalijus

    2014-08-01

    The goal was to assess the aerobic capacity of boxers and its relation with sport mastery. Participants were 12 boxers from the Lithuanian national team (VO₂max - 58.03 ± 3.00 ml/kg/min) of different weight classes. Their sport mastery ranking was established according to their achieved results during the last years of participation in amateur boxing contests. In a graduated treadmill running test, the boxers' aerobic capacity indices were established. Running speed at first and second ventilatory thresholds, VO₂max, and maximal oxygen pulse had moderate to strong correlations with the boxers' sport mastery ranking. Aerobic capacity is an important fitness component of boxers in all weight categories. Special attention should be paid to development of cardiac capacity in the boxers' training processes, as with aerobic power and anaerobic threshold training. PMID:25153738

  4. Aerobic exercise and endurance: improving fitness for health benefits.

    PubMed

    Wilmore, Jack H

    2003-05-01

    Clinicians who understand how the body responds to exercise, how aerobic training improves cardiovascular fitness, and the benefits and principles of prescribing aerobic exercise can effectively encourage patients to become active and optimize programs for those already active. Patients who are active at an early age and who continue to enjoy active lifestyles as adults will attenuate the normal losses in cardiovascular endurance, strength, and flexibility that accompany aging and sedentary living, thereby maintaining greater independence throughout their life spans. PMID:20086470

  5. Surface Structure of Aerobically Oxidized Diamond Nanocrystals

    DOE PAGESBeta

    Wolcott, Abraham; Schiros, Theanne; Trusheim, Matthew E.; Chen, Edward H.; Nordlund, Dennis; Diaz, Rosa E.; Gaaton, Ophir; Englund, Dirk; Owen, Jonathan S.

    2014-10-27

    Here we investigate the aerobic oxidation of high-pressure, high-temperature nanodiamonds (5–50 nm dimensions) using a combination of carbon and oxygen K-edge X-ray absorption, wavelength-dependent X-ray photoelectron, and vibrational spectroscopies. Oxidation at 575 °C for 2 h eliminates graphitic carbon contamination (>98%) and produces nanocrystals with hydroxyl functionalized surfaces as well as a minor component (<5%) of carboxylic anhydrides. The low graphitic carbon content and the high crystallinity of HPHT are evident from Raman spectra acquired using visible wavelength excitation (λexcit = 633 nm) as well as carbon K-edge X-ray absorption spectra where the signature of a core–hole exciton is observed.more » Both spectroscopic features are similar to those of chemical vapor deposited (CVD) diamond but differ significantly from the spectra of detonation nanodiamond. Lastly, we discuss the importance of these findings to the functionalization of nanodiamond surfaces for biological labeling applications.« less

  6. Maximal aerobic exercise following prolonged sleep deprivation.

    PubMed

    Goodman, J; Radomski, M; Hart, L; Plyley, M; Shephard, R J

    1989-12-01

    The effect of 60 h without sleep upon maximal oxygen intake was examined in 12 young women, using a cycle ergometer protocol. The arousal of the subjects was maintained by requiring the performance of a sequence of cognitive tasks throughout the experimental period. Well-defined oxygen intake plateaus were obtained both before and after sleep deprivation, and no change of maximal oxygen intake was observed immediately following sleep deprivation. The endurance time for exhausting exercise also remained unchanged, as did such markers of aerobic performance as peak exercise ventilation, peak heart rate, peak respiratory gas exchange ratio, and peak blood lactate. However, as in an earlier study of sleep deprivation with male subjects (in which a decrease of treadmill maximal oxygen intake was observed), the formula of Dill and Costill (4) indicated the development of a substantial (11.6%) increase of estimated plasma volume percentage with corresponding decreases in hematocrit and red cell count. Possible factors sustaining maximal oxygen intake under the conditions of the present experiment include (1) maintained arousal of the subjects with no decrease in peak exercise ventilation or the related respiratory work and (2) use of a cycle ergometer rather than a treadmill test with possible concurrent differences in the impact of hematocrit levels and plasma volume expansion upon peak cardiac output and thus oxygen delivery to the working muscles. PMID:2628360

  7. Dancing the aerobics ''hearing loss'' choreography

    NASA Astrophysics Data System (ADS)

    Pinto, Beatriz M.; Carvalho, Antonio P. O.; Gallagher, Sergio

    2002-11-01

    This paper presents an overview of gymnasiums' acoustic problems when used for aerobics exercises classes (and similar) with loud noise levels of amplified music. This type of gymnasium is usually a highly reverberant space, which is a consequence of a large volume surrounded by hard surfaces. A sample of five schools in Portugal was chosen for this survey. Noise levels in each room were measured using a precision sound level meter, and analyzed to calculate the standardized daily personal noise exposure levels (LEP,d). LEP,d values from 79 to 91 dB(A) were found to be typical values in this type of room, inducing a health risk for its occupants. The reverberation time (RT) values were also measured and compared with some European legal requirements (Portugal, France, and Belgium) for nearly similar situations. RT values (1 kHz) from 0.9 s to 2.8 s were found. These reverberation time values clearly differentiate between good and acoustically inadequate rooms. Some noise level and RT limits for this type of environment are given and suggestions for the improvement of the acoustical environment are shown. Significant reductions in reverberation time values and noise levels can be obtained by simple measures.

  8. Respirometric assessment of aerobic sludge stabilization.

    PubMed

    Tas, Didem Okutman

    2010-04-01

    Aerobic sludge stabilization was assessed respirometrically with the sludge taken from the secondary settling tank of a domestic wastewater treatment facility in Istanbul, Turkey. Zero-order removal rates of 178, 127 and 44 mg/L day were found for Suspended Solids (SS), Volatile Suspended Solids (VSS) and Total Organic Carbon (TOC) at the end of 18 days sludge stabilization, respectively. Significant nutrient release was observed by the mineralized nitrogen and phosphorus from the death and lysis of microorganisms. The model simulations for the batch respirometric assays for initial, 7th and 18th days of the stabilization agree reasonably well with the experimental data. The maximum storage rates (k(sto)) as well as maximum growth rates on stored products (micro(H2)) decrease with increasing stabilization period. Respirometric assays indicated the presence of microorganisms that started to compete with the dominant microorganisms as a result of the stabilization. As such, these findings have significance in terms of the efforts related to the sludge management and application processes. PMID:19942430

  9. Late Archean rise of aerobic microbial ecosystems

    PubMed Central

    Eigenbrode, Jennifer L.; Freeman, Katherine H.

    2006-01-01

    We report the 13C content of preserved organic carbon for a 150 million-year section of late Archean shallow and deepwater sediments of the Hamersley Province in Western Australia. We find a 13C enrichment of ≈10‰ in organic carbon of post-2.7-billion-year-old shallow-water carbonate rocks relative to deepwater sediments. The shallow-water organic-carbon 13C content has a 29‰ range in values (−57 to −28‰), and it contrasts with the less variable but strongly 13C-depleted (−40 to −45‰) organic carbon in deepwater sediments. The 13C enrichment likely represents microbial habitats not as strongly influenced by assimilation of methane or other 13C-depleted substrates. We propose that continued oxidation of shallow settings favored the expansion of aerobic ecosystems and respiring organisms, and, as a result, isotopic signatures of preserved organic carbon in shallow settings approached that of photosynthetic biomass. Facies analysis of published carbon-isotopic records indicates that the Hamersley shallow-water signal may be representative of a late Archean global signature and that it preceded a similar, but delayed, 13C enrichment of deepwater deposits. The data suggest that a global-scale expansion of oxygenated habitats accompanied the progression away from anaerobic ecosystems toward respiring microbial communities fueled by oxygenic photosynthesis before the oxygenation of the atmosphere after 2.45 billion years ago. PMID:17043234

  10. Personality, Metabolic Rate and Aerobic Capacity

    PubMed Central

    Terracciano, Antonio; Schrack, Jennifer A.; Sutin, Angelina R.; Chan, Wayne; Simonsick, Eleanor M.; Ferrucci, Luigi

    2013-01-01

    Personality traits and cardiorespiratory fitness in older adults are reliable predictors of health and longevity. We examined the association between personality traits and energy expenditure at rest (basal metabolic rate) and during normal and maximal sustained walking. Personality traits and oxygen (VO2) consumption were assessed in 642 participants from the Baltimore Longitudinal Study of Aging. Results indicate that personality traits were mostly unrelated to resting metabolic rate and energy expenditure at normal walking pace. However, those who scored lower on neuroticism (r =  −0.12) and higher on extraversion (r = 0.11), openness (r = 0.13), and conscientiousness (r = 0.09) had significantly higher energy expenditure at peak walking pace. In addition to greater aerobic capacity, individuals with a more resilient personality profile walked faster and were more efficient in that they required less energy per meter walked. The associations between personality and energy expenditure were not moderated by age or sex, but were in part explained by the proportion of fat mass. In conclusion, differences in personality may matter the most during more challenging activities that require cardiorespiratory fitness. These findings suggest potential pathways that link personality to health outcomes, such as obesity and longevity. PMID:23372763

  11. Surface Structure of Aerobically Oxidized Diamond Nanocrystals

    SciTech Connect

    Wolcott, Abraham; Schiros, Theanne; Trusheim, Matthew E.; Chen, Edward H.; Nordlund, Dennis; Diaz, Rosa E.; Gaaton, Ophir; Englund, Dirk; Owen, Jonathan S.

    2014-10-27

    Here we investigate the aerobic oxidation of high-pressure, high-temperature nanodiamonds (5–50 nm dimensions) using a combination of carbon and oxygen K-edge X-ray absorption, wavelength-dependent X-ray photoelectron, and vibrational spectroscopies. Oxidation at 575 °C for 2 h eliminates graphitic carbon contamination (>98%) and produces nanocrystals with hydroxyl functionalized surfaces as well as a minor component (<5%) of carboxylic anhydrides. The low graphitic carbon content and the high crystallinity of HPHT are evident from Raman spectra acquired using visible wavelength excitation (λexcit = 633 nm) as well as carbon K-edge X-ray absorption spectra where the signature of a core–hole exciton is observed. Both spectroscopic features are similar to those of chemical vapor deposited (CVD) diamond but differ significantly from the spectra of detonation nanodiamond. Lastly, we discuss the importance of these findings to the functionalization of nanodiamond surfaces for biological labeling applications.

  12. The mechanistic basis of aerobic performance variation in red junglefowl.

    PubMed

    Hammond, K A; Chappell, M A; Cardullo, R A; Lin, R; Johnsen, T S

    2000-07-01

    We examined aerobic performance, organ and muscle mass and enzymatic activity in red junglefowl (Gallus gallus). We tested three models of performance limitation (central limits, peripheral limits, symmorphosis) and explored relationships between basal metabolic rate (BMR), aerobic capacity ( V (O2max)) and social rank. Males had a lower BMR, a higher V (O2max) and a greater aerobic scope than females. Females possessed larger peritoneal and reproductive organs, while males had larger hearts, lungs and leg muscles. In females, BMR was correlated with spleen mass and V (O2max) was correlated with hematocrit and large intestine mass. Male BMR was correlated with intestinal tract and lung mass, and V (O2max) was correlated with heart and pectoralis mass. Male citrate synthase activity averaged 57 % higher than that of females and was correlated with V (O2max) (this correlation was not significant in females). Female social status was not correlated with any variable, but male dominance was associated with higher aerobic scope, larger heart and lungs, smaller peritoneal organs and greater leg citrate synthase activity. We conclude that aerobic capacity is controlled by system-wide limitations (symmorphosis) in males, while in females it is controlled by central organs. In neither sex is elevated aerobic capacity associated with increased maintenance costs. PMID:10851122

  13. Enhanced selection of micro-aerobic pentachlorophenol degrading granular sludge.

    PubMed

    Lv, Yuancai; Chen, Yuancai; Song, Wenzhe; Hu, Yongyou

    2014-09-15

    Column-type combined reactors were designed to cultivate micro-aerobic pentachlorophenol (PCP) degrading granular sludge under oxygen-limited conditions (0.1-0.2 mgL(-1)) over 39-day experimental period. Micro-aerobic granular had both anaerobic activity (SMA: 2.34 mMCH4/hg VSS) and aerobic activity (SOUR: 2.21 mMO2/hg VSS). Metabolite analysis results revealed that PCP was sequentially dechlorinated to TCP, DCP, and eventually to MCP. Methanogens were not directly involved in the dechlorination of PCP, but might played a vital role in stabilizing the overall structure of the granule sludge. For Eubacteria, the Shannon Index (2.09 in inoculated granular sludge) increased both in micro-aerobic granular sludge (2.61) and PCP-degradation granular sludge (2.55). However, for Archaea, it decreased from 2.53 to 1.85 and 1.84, respectively. Although the Shannon Index demonstrated slight difference between micro-aerobic granular sludge and PCP-degradation granular sludge, the Principal Component Analysis (PCA) indicated obvious variance of the microbial composition, revealing significant effect of micro-aerobic condition and PCP on microbial community. Furthermore, nucleotide sequencing indicated that the main microorganisms for PCP degradation might be related to Actinobacterium and Sphingomonas. These results provided insights into situ bioremediation of environments contaminated by PCP and had practical implications for the strategies of PCP degradation. PMID:25151236

  14. Sludge minimization using aerobic/anoxic treatment technology

    SciTech Connect

    Mines, R.O. Jr.; Kalch, R.S.

    1999-07-01

    The objective of this investigation was to demonstrate through a bench-scale study that using an aerobic/anoxic sequence to treat wastewater and biosolids could significantly reduce the production of biosolids (sludge). A bench-scale activated sludge reactor and anoxic digester were operated for approximately three months. The process train consisted of a completely-mixed aerobic reactor with wasting of biosolids to an anoxic digester for stabilization. The system was operated such that biomass produced in the aerobic activated sludge process was wasted to the anoxic digester; and biomass produced in the anoxic digester was wasted back to the activated sludge process. A synthetic wastewater consisting of bacto-peptone nutrient broth was fed to the liquid process train. Influent and effluent to the aerobic biological process train were analytically tested, as were the contents of mixed liquor in the aerobic reactor and anoxic digester. Overall removal efficiencies for the activated sludge process with regard to COD, TKN, NH{sub 3}-N, and alkalinity averaged 91, 89, 98, and 38%, respectively. The overall average sludge production for the aerobic/anoxic process was 24% less than the overall average sludge production from a conventional activated sludge bench-scale system fed the same substrate and operated under similar mean cell residence times.

  15. Aerobic microbial mineralization of dichloroethene as sole carbon substrate

    USGS Publications Warehouse

    Bradley, P.M.; Chapelle, F.H.

    2000-01-01

    Microorganisms indigenous to the bed sediments of a black- water stream utilized 1,2-dichloroethene (1,2-DCE) as a sole carbon substrate for aerobic metabolism. Although no evidence of growth was observed in the minimal salts culture media used in this study, efficient aerobic microbial mineralization of 1,2-DCE as sole carbon substrate was maintained through three sequential transfers (107 final dilution) of the original environmental innoculum. These results indicate that 1,2-DCE can be utilized as a primary substrate to support microbial metabolism under aerobic conditions.Microorganisms indigenous to the bed sediments of a black-water stream utilized 1,2-dichloroethene (1,2-DCE) as a sole carbon substrate for aerobic metabolism. Although no evidence of growth was observed in the minimal salts culture media used in this study, efficient aerobic microbial mineralization of 1,2-DCE as sole carbon substrate was maintained through three sequential transfers (107 final dilution) of the original environmental innoculum. These results indicate that 1,2-DCE can be utilized as a primary substrate to support microbial metabolism under aerobic conditions.

  16. Maternal and fetal responses to low-impact aerobic dance.

    PubMed

    McMurray, R G; Katz, V L; Poe, M P; Hackney, A C

    1995-07-01

    The purpose of this study was to compare the physiologic responses to low-impact aerobics using treadmill walking as a control. Ten pregnant women between 21 and 28 weeks of gestation completed 40 minutes of low-impact aerobic dance. The maternal and fetal responses were then compared to 40 minutes of walking at the same heart rate. The aerobics program consisted of a 10-minute warm-up, 20 minutes of high-intensity exercise, and 10 minutes of decreasing intensity. Heart rates were recorded every 5 minutes, and oxygen uptake (VO2) and fetal response (real-time ultrasound) were obtained every 10 minutes. The maternal heart rates were similar during both trials (overall, 133 +/- 6 beat/min). VO2 values during walking were about 4 mL/kg/min greater than during aerobic dance (p < or = 0.003). Minute ventilation (VE) was also greater during walking (28.7 +/- 6.4 versus 24.1 +/- 3.4 L/min, p < or = 0.001). Respiratory exchange ratios and the ventilatory equivalents for oxygen (VE/VO2) were similar for both trials. Aerobic dance caused greater fetal heart rates than walking (p < or = 0.001), differences being as high as 25 beat/min. The fetal rates had returned toward rest within 5 minutes following exercise. Low-impact aerobic dance, compared with walking at similar heart rates, results in a lower maternal metabolic rate and increases the transient stress on the fetus. PMID:7575837

  17. Tolerance to organic loading rate by aerobic granular sludge in a cyclic aerobic granular reactor.

    PubMed

    Long, Bei; Yang, Chang-zhu; Pu, Wen-hong; Yang, Jia-kuan; Liu, Fu-biao; Zhang, Li; Zhang, Jing; Cheng, Kai

    2015-04-01

    Sodium acetate as carbon source, tolerance to organic loading rate (OLR) by aerobic granular sludge in a cyclic aerobic granular reactor (CAGR) was investigated by gradually increasing the influent COD. AGS could maintain stability in the continuous flow reactor under OLR⩽15kg/m(3)d in the former 65 days, and SVI, granulation rate, average particle size and water content was 21 ml/g, 98%, 1.8mm and 97.2% on the 65th day. However, AGS gradually disintegrated after the 66 th day when OLR increased to 18 kg/m(3)d, and granules' properties deteriorated rapidly in a short time. High removal rates to pollutants were achieved by CAGR in the former 65 days, but the removal rates of pollutants dropped sharply from the 66 th day. With the increase of OLR and particle size, anaerobic cores inside the granules were formed by massive dead cells, while instability of anaerobic core eventually led to the collapse of the system. PMID:25710570

  18. Aerobic and anaerobic microbiology of infections after trauma in children.

    PubMed Central

    Brook, I

    1998-01-01

    OBJECTIVE: To review the recovery of aerobic and anaerobic bacteria from infections after trauma in children over a 20 year period. METHODS: Only specimens that were studied for both aerobic and anaerobic bacteria were included in the analysis. They were collected from seven separate centres in which the microbiology laboratories only accepted specimens that were properly collected without contamination and were submitted in appropriate transport media. Anaerobes and aerobic bacteria were cultured and identified using standard techniques. Clinical records were reviewed to identify post-trauma patients. RESULTS: From 1974 to 1994, 175 specimens obtained from 166 children with trauma showed bacterial growth. The trauma included blunt trauma (71), lacerations (48), bites (42), and open fractures (5). Anaerobic bacteria only were isolated in 38 specimens (22%), aerobic bacteria only in 51 (29%), and mixed aerobic-anaerobic flora in 86 (49%); 363 anaerobic (2.1/specimen) and 158 aerobic or facultative isolates (0.9/specimen) were recovered. The predominant anaerobic bacteria included Peptostreptococcus spp (115 isolates), Prevotella spp (68), Fusobacterium spp (52), B fragilis group (42), and Clostridium spp (21). The predominant aerobic bacteria included Staph aureus (51), E coli (13), Ps aeruginosa (12), Str pyogenes (11) and Klebsiella pneumoniae (9). Principal infections were: abscesses (52), bacteraemia (3), pulmonary infections (30, including aspiration pneumonia, tracheostomy associated pneumonia, empyema, and ventilator associated pneumonia), wounds (36, including cellulitis, post-traumatic wounds, decubitus ulcers, myositis, gastrostomy and tracheostomy site wounds, and fasciitis), bites (42, including 23 animal and 19 human), peritonitis (4), osteomyelitis (5), and sinusitis (3). Staph aureus and Str pyogenes were isolated at all sites. However, organisms of the oropharyngeal flora predominated in infections that originated from head and neck wounds and

  19. Field tests for evaluating the aerobic work capacity of firefighters.

    PubMed

    Lindberg, Ann-Sofie; Oksa, Juha; Gavhed, Désirée; Malm, Christer

    2013-01-01

    Working as a firefighter is physically strenuous, and a high level of physical fitness increases a firefighter's ability to cope with the physical stress of their profession. Direct measurements of aerobic capacity, however, are often complicated, time consuming, and expensive. The first aim of the present study was to evaluate the correlations between direct (laboratory) and indirect (field) aerobic capacity tests with common and physically demanding firefighting tasks. The second aim was to give recommendations as to which field tests may be the most useful for evaluating firefighters' aerobic work capacity. A total of 38 subjects (26 men and 12 women) were included. Two aerobic capacity tests, six field tests, and seven firefighting tasks were performed. Lactate threshold and onset of blood lactate accumulation were found to be correlated to the performance of one work task (r(s) = -0.65 and -0.63, p<0.01, respectively). Absolute (mL · min(-1)) and relative (mL · kg(-1) · min(-1)) maximal aerobic capacity was correlated to all but one of the work tasks (r(s) = -0.79 to 0.55 and -0.74 to 0.47, p<0.01, respectively). Aerobic capacity is important for firefighters' work performance, and we have concluded that the time to row 500 m, the time to run 3000 m relative to body weight (s · kg(-1)), and the percent of maximal heart rate achieved during treadmill walking are the most valid field tests for evaluating a firefighter's aerobic work capacity. PMID:23844153

  20. Summary report on the aerobic degradation of diesel fuel and the degradation of toluene under aerobic, denitrifying and sulfate reducing conditions

    SciTech Connect

    Coyne, P.; Smith, G.

    1995-08-15

    This report contains a number of studies that were performed to better understand the technology of the biodegradation of petroleum hydrocarbons. Topics of investigation include the following: diesel fuel degradation by Rhodococcus erythropolis; BTEX degradation by soil isolates; aerobic degradation of diesel fuel-respirometry; aerobic degradation of diesel fuel-shake culture; aerobic toluene degradation by A3; effect of HEPES, B1, and myo-inositol addition on the growth of A3; aerobic and anaerobic toluene degradation by contaminated soils; denitrifying bacteria MPNs; sulfate-reducing bacteria MPNs; and aerobic, DNB and SRB enrichments.

  1. Comparison of Aerobic and Anaerobic Biodegradation of Sugarcane Vinasse.

    PubMed

    Mota, V T; Araújo, T A; Amaral, M C S

    2015-07-01

    Vinasse is the main liquid waste from ethanol production, and it has a considerable pollution potential. Biological treatment is a promising alternative to reduce its organic load. The aim of this study was to analyze the biodegradation of sugarcane juice vinasse in aerobic and anaerobic conditions. The content of carbohydrates, proteins and volatile fatty acids was evaluated. Vinasse samples showed a high biodegradability (>96.5 %) and low percentage of inert chemical oxygen demand (COD) (<3.2 %) in both aerobic and anaerobic conditions. The rates of substrate utilization were slightly higher in aerobic reactors, but COD stabilization occurred simultaneously in the anaerobic reactors, confirming its suitability for anaerobic digestion. Inert COD in anaerobic conditions was lower than in aerobic conditions. On the other hand, COD from metabolic products in the anaerobic reactors was higher than in the aerobic ones, indicating an increased release of soluble microbial products (SMPs) by anaerobic microorganisms. The results indicated that carbohydrates were satisfactorily degraded and protein-like substances were the major components remaining after biological degradation of vinasse. PMID:25957273

  2. Gender difference in anaerobic capacity: role of aerobic contribution.

    PubMed Central

    Hill, D W; Smith, J C

    1993-01-01

    The purpose of this study was to evaluate effects of gender on anaerobic and aerobic contributions to high-intensity exercise. A group of 38 subjects (22 women, 16 men) performed modified Wingate tests against resistances of 0.086 kg kg-1 body mass (0.844 N kg-1) for women and 0.095 kg kg-1 body mass (0.932 N kg-1) for men. The aerobic contribution to total work performed was determined from breath-by-breath analyses of expired gases during each test. Total work in 30 s was 30% lower (Student's t test; P < 0.01) in women than men (211 +/- 5 J kg-1 versus 299 +/- 14 J kg-1). Aerobic contribution was only 7% lower (P = 0.12) in women than men (53 +/- 1 J kg-1 versus 57 +/- 2 J kg-1). The anaerobic component of the work performed, determined by subtraction of the aerobic component from total work in 30 s, was 35% lower (P < 0.01) in women than men (158 +/- 5 J kg-1 versus 242 +/- 15 J kg-1). It is concluded that, because women provide a relatively higher (P < 0.01) portion of the energy for a 30-s test aerobically than men (25% versus 20%), total work during a Wingate test actually underestimates the gender difference in anaerobic capacity between women and men. PMID:8457813

  3. Denitrification characteristics of a marine origin psychrophilic aerobic denitrifying bacterium.

    PubMed

    Zheng, Haiyan; Liu, Ying; Sun, Guangdong; Gao, Xiyan; Zhang, Qingling; Liu, Zhipei

    2011-01-01

    A psychrophilic aerobic denitrifying bacterium, strain S1-1, was isolated from a biological aerated filter conducted for treatment of recirculating water in a marine aquaculture system. Strain S1-1 was preliminarily identified as Psychrobacter sp. based on the analysis of its 16S rRNA gene sequence, which showed 100% sequence similarity to that of Psychrobacter sp. TSBY-70. Strain S1-1 grew well either in high nitrate or high nitrite conditions with a removal of 100% nitrate or 63.50% nitrite, and the total nitrogen removal rates could reach to 46.48% and 31.89%, respectively. The results indicated that nitrate was mainly reduced in its logarithmic growth phase with a very low level accumulation of nitrite, suggesting that the aerobic denitrification process of strain S1-1 occurred mainly in this phase. The GC-MS results showed that N2O was formed as the major intermediate during the aerobic denitrifying process of strain S1-1. Finally, factors affecting the growth of strain S1-1 and its aerobic denitrifying ability were also investigated. Results showed that the optimum aerobic denitrification conditions for strain S1-1 were sodium succinate as carbon source, C/N ratio15, salinity 10 g/L NaCl, incubation temperature 20 degrees C and initial pH 6.5. PMID:22432315

  4. Mood alterations in mindful versus aerobic exercise modes.

    PubMed

    Netz, Yael; Lidor, Ronnie

    2003-09-01

    The results of most recent studies have generally indicated an improvement in mood after participation in aerobic exercise. However, only a few researchers have compared mindful modes of exercise with aerobic exercise to examine the effect of 1 single session of exercise on mood. In the present study, the authors assessed state anxiety, depressive mood, and subjective well-being prior to and following 1 class of 1 of 4 exercise modes: yoga, Feldenkrais (awareness through movement), aerobic dance, and swimming; a computer class served as a control. Participants were 147 female general curriculum and physical education teachers (mean age = 40.15, SD = 0.2) voluntarily enrolled in a 1-year enrichment program at a physical education college. Analyses of variance for repeated measures revealed mood improvement following Feldenkrais, swimming, and yoga but not following aerobic dance and computer lessons. Mindful low-exertion activities as well as aerobic activities enhanced mood in 1 single session of exercise. The authors suggest that more studies assessing the mood-enhancing benefits of mindful activities such as Feldenkrais and yoga are needed. PMID:14629072

  5. Aerobic Denitrifying Bacteria That Produce Low Levels of Nitrous Oxide

    PubMed Central

    Takaya, Naoki; Catalan-Sakairi, Maria Antonina B.; Sakaguchi, Yasushi; Kato, Isao; Zhou, Zhemin; Shoun, Hirofumi

    2003-01-01

    Most denitrifiers produce nitrous oxide (N2O) instead of dinitrogen (N2) under aerobic conditions. We isolated and characterized novel aerobic denitrifiers that produce low levels of N2O under aerobic conditions. We monitored the denitrification activities of two of the isolates, strains TR2 and K50, in batch and continuous cultures. Both strains reduced nitrate (NO3−) to N2 at rates of 0.9 and 0.03 μmol min−1 unit of optical density at 540 nm−1 at dissolved oxygen (O2) (DO) concentrations of 39 and 38 μmol liter−1, respectively. At the same DO level, the typical denitrifier Pseudomonas stutzeri and the previously described aerobic denitrifier Paracoccus denitrificans did not produce N2 but evolved more than 10-fold more N2O than strains TR2 and K50 evolved. The isolates denitrified NO3− with concomitant consumption of O2. These results indicated that strains TR2 and K50 are aerobic denitrifiers. These two isolates were taxonomically placed in the β subclass of the class Proteobacteria and were identified as P. stutzeri TR2 and Pseudomonas sp. strain K50. These strains should be useful for future investigations of the mechanisms of denitrifying bacteria that regulate N2O emission, the single-stage process for nitrogen removal, and microbial N2O emission into the ecosystem. PMID:12788710

  6. Impact of brisk walking and aerobics in overweight women

    PubMed Central

    Melam, Ganeswara Rao; Alhusaini, Adel A; Buragadda, Syamala; Kaur, Taranpreet; Khan, Imran Ali

    2016-01-01

    [Purpose] Lack of physical activity and an uncontrolled diet cause excessive weight gain, which leads to obesity and other metabolic disorders. Studies have indicated that brisk walking and aerobics are the best methods for controlling and reducing weight and body mass composition. [Subjects and Methods] In this study, 45 overweight women were enrolled and divided into 3 groups. Women not involved in brisk walking or aerobics were included in group A (n = 15) as control subjects; women involved in brisk walking were in group B (n = 15); and those involved in aerobics were in group C (n = 15). [Results] This program was carried out 5 days/week for 10 weeks. Pre- and post-measurements of body mass index, waist and hip circumference, and skinfold thickness of the abdomen, subscapular area, biceps, and triceps were recorded for the women in all 3 groups. All values decreased in women who participated in brisk walking and aerobics for 10 weeks. [Conclusion] These results indicate that aerobics with diet therapy is a more effective intervention program for controlling and reducing body mass index and skinfold thickness than brisk walking with diet therapy in North Indian women. PMID:26957777

  7. Effects of 12 weeks of aerobic training on autonomic modulation, mucociliary clearance, and aerobic parameters in patients with COPD

    PubMed Central

    Leite, Marceli Rocha; Ramos, Ercy Mara Cipulo; Kalva-Filho, Carlos Augusto; Freire, Ana Paula Coelho Figueira; de Alencar Silva, Bruna Spolador; Nicolino, Juliana; de Toledo-Arruda, Alessandra Choqueta; Papoti, Marcelo; Vanderlei, Luiz Carlos Marques; Ramos, Dionei

    2015-01-01

    Introduction Patients with chronic obstructive pulmonary disease (COPD) exhibit aerobic function, autonomic nervous system, and mucociliary clearance alterations. These parameters can be attenuated by aerobic training, which can be applied with continuous or interval efforts. However, the possible effects of aerobic training, using progressively both continuous and interval sessions (ie, linear periodization), require further investigation. Aim To analyze the effects of 12-week aerobic training using continuous and interval sessions on autonomic modulation, mucociliary clearance, and aerobic function in patients with COPD. Methods Sixteen patients with COPD were divided into an aerobic (continuous and interval) training group (AT) (n=10) and a control group (CG) (n=6). An incremental test (initial speed of 2.0 km·h−1, constant slope of 3%, and increments of 0.5 km·h−1 every 2 minutes) was performed. The training group underwent training for 4 weeks at 60% of the peak velocity reached in the incremental test (vVO2peak) (50 minutes of continuous effort), followed by 4 weeks of sessions at 75% of vVO2peak (30 minutes of continuous effort), and 4 weeks of interval training (5×3-minute effort at vVO2peak, separated by 1 minute of passive recovery). Intensities were adjusted through an incremental test performed at the end of each period. Results The AT presented an increase in the high frequency index (ms2) (P=0.04), peak oxygen uptake (VO2peak) (P=0.01), vVO2peak (P=0.04), and anaerobic threshold (P=0.02). No significant changes were observed in the CG (P>0.21) group. Neither of the groups presented changes in mucociliary clearance after 12 weeks (AT: P=0.94 and CG: P=0.69). Conclusion Twelve weeks of aerobic training (continuous and interval sessions) positively influenced the autonomic modulation and aerobic parameters in patients with COPD. However, mucociliary clearance was not affected by aerobic training. PMID:26648712

  8. Cellular hallmarks reveal restricted aerobic metabolism at thermal limits

    PubMed Central

    Neves, Aitana; Busso, Coralie; Gönczy, Pierre

    2015-01-01

    All organisms live within a given thermal range, but little is known about the mechanisms setting the limits of this range. We uncovered cellular features exhibiting signature changes at thermal limits in Caenorhabditis elegans embryos. These included changes in embryo size and shape, which were also observed in Caenorhabditis briggsae, indicating evolutionary conservation. We hypothesized that such changes could reflect restricted aerobic capacity at thermal limits. Accordingly, we uncovered that relative respiration in C. elegans embryos decreases at the thermal limits as compared to within the thermal range. Furthermore, by compromising components of the respiratory chain, we demonstrated that the reliance on aerobic metabolism is reduced at thermal limits. Moreover, embryos thus compromised exhibited signature changes in size and shape already within the thermal range. We conclude that restricted aerobic metabolism at the thermal limits contributes to setting the thermal range in a metazoan organism. DOI: http://dx.doi.org/10.7554/eLife.04810.001 PMID:25929283

  9. Aerobic and anaerobic cellulase production by Cellulomonas uda.

    PubMed

    Poulsen, Henrik Vestergaard; Willink, Fillip Wolfgang; Ingvorsen, Kjeld

    2016-10-01

    Cellulomonas uda (DSM 20108/ATCC 21399) is one of the few described cellulolytic facultative anaerobes. Based on these characteristics, we initiated a physiological study of C. uda with the aim to exploit it for cellulase production in simple bioreactors with no or sporadic aeration. Growth, cellulase activity and fermentation product formation were evaluated in different media under both aerobic and anaerobic conditions and in experiments where C. uda was exposed to alternating aerobic/anaerobic growth conditions. Here we show that C. uda behaves as a true facultative anaerobe when cultivated on soluble substrates such as glucose and cellobiose, but for reasons unknown cellulase activity is only induced under aerobic conditions on insoluble cellulosic substrates and not under anaerobic conditions. These findings enhance knowledge on the limited number of described facultative cellulolytic anaerobes, and in addition it greatly limits the utility of C. uda as an 'easy to handle' cellulase producer with low aeration demands. PMID:27154570

  10. Influence of aerobic and anoxic microenvironments on polyhydroxyalkanoates (PHA) production from food waste and acidogenic effluents using aerobic consortia.

    PubMed

    Reddy, M Venkateswar; Mohan, S Venkata

    2012-01-01

    The functional role of aerobic and anoxic microenvironments on polyhydroxyalkanoates (PHA) production using food waste (UFW) and effluents from acidogenic biohydrogen production process (FFW) were studied employing aerobic mixed culture as biocatalyst. Anoxic microenvironment documented higher PHA production, while aerobic microenvironment showed higher substrate degradation. FFW showed higher PHA accumulation (39.6%) than UFW (35.6%) due to ready availability of precursors (fatty acids). Higher fraction of poly-3-hydroxy butyrate (PHB) was observed compared to poly-3-hydroxy valerate (PHV) in the accumulated PHA in the form of co-polymer [P3(HB-co-HV)]. Dehydrogenase, phosphatase and protease enzymatic activities were monitored during process operation. Integration with fermentative biohydrogen production yielded additional substrate degradation under both aerobic (78%) and anoxic (72%) microenvironments apart from PHA production. Microbial community analysis documented the presence of aerobic and facultative organisms capable of producing PHA. Integration strategy showed feasibility of producing hydrogen along with PHA by consuming fatty acids generated during acidogenic process in association with increased treatment efficiency. PMID:22055090

  11. Supplementary low-intensity aerobic training improves aerobic capacity and does not affect psychomotor performance in professional female ballet dancers.

    PubMed

    Smol, Ewelina; Fredyk, Artur

    2012-03-01

    We investigated whether 6-week low-intensity aerobic training program used as a supplement to regular dance practice might improve both the aerobic capacity and psychomotor performance in female ballet dancers. To assess their maximal oxygen uptake (VO2max) and anaerobic threshold (AT), the dancers performed a standard graded bicycle ergometer exercise test until volitional exhaustion prior to and after the supplementary training. At both these occasions, the psychomotor performance (assessed as multiple choice reaction time) and number of correct responses to audio-visual stimuli was assessed at rest and immediately after cessation of maximal intensity exercise. The supplementary low-intensity exercise training increased VO2max and markedly shifted AT toward higher absolute workload. Immediately after completion of the graded exercise to volitional exhaustion, the ballerinas' psychomotor performance remained at the pre-exercise (resting) level. Neither the resting nor the maximal multiple choice reaction time and accuracy of responses were affected by the supplementary aerobic training. The results of this study indicate that addition of low-intensity aerobic training to regular dance practice increases aerobic capacity of ballerinas with no loss of speed and accuracy of their psychomotor reaction. PMID:23485962

  12. Supplementary Low-Intensity Aerobic Training Improves Aerobic Capacity and Does Not Affect Psychomotor Performance in Professional Female Ballet Dancers

    PubMed Central

    Smol, Ewelina; Fredyk, Artur

    2012-01-01

    We investigated whether 6-week low-intensity aerobic training program used as a supplement to regular dance practice might improve both the aerobic capacity and psychomotor performance in female ballet dancers. To assess their maximal oxygen uptake (VO2max) and anaerobic threshold (AT), the dancers performed a standard graded bicycle ergometer exercise test until volitional exhaustion prior to and after the supplementary training. At both these occasions, the psychomotor performance (assessed as multiple choice reaction time) and number of correct responses to audio-visual stimuli was assessed at rest and immediately after cessation of maximal intensity exercise. The supplementary low-intensity exercise training increased VO2max and markedly shifted AT toward higher absolute workload. Immediately after completion of the graded exercise to volitional exhaustion, the ballerinas’ psychomotor performance remained at the pre-exercise (resting) level. Neither the resting nor the maximal multiple choice reaction time and accuracy of responses were affected by the supplementary aerobic training. The results of this study indicate that addition of low-intensity aerobic training to regular dance practice increases aerobic capacity of ballerinas with no loss of speed and accuracy of their psychomotor reaction. PMID:23485962

  13. Lipid Biomarkers Indicating Aerobic Methanotrophy at Ancient Marine Methane- Seeps

    NASA Astrophysics Data System (ADS)

    Birgel, D.; Peckmann, J.

    2007-12-01

    The inventory of lipid biomarkers of a number of ancient methane-seep limestones has been studied over the last decade. The molecular fingerprints of the chemosynthesis-based microbial communities tend to be extremely well-preserved in these limestones. The key process at seeps is the anaerobic oxidation of methane, performed by consortia of sulfate-reducing bacteria and methanotrophic archaea. Compounds preserved within modern and ancient seep settings comprise C-13-depleted lipid biomarkers. Besides the occurrence of C-13- depleted isoprenoids (archaea) and n-alkyl-chains (bacteria), C-13-depleted hopanoids have been reported in seep limestones. Here, lipid biomarker data are presented from three ancient methane-seep limestones embedded in Miocene and Campanian strata. These examples provide strong evidence that methane was not solely oxidized by an anaerobic process. In a Miocene limestone, 3-beta-methylated hopanoids were found (delta C-13: -100 per mil). Most likely, 3-beta-methylated hopanepolyols, prevailing in aerobic methanotrophs were the precursor lipids. In another Miocene limestone, a series of C-13-depleted 4-methylated steranes (lanostanes; -80 to -70 per mil) is derived from aerobic methanotrophs. Lanosterol is the most likely precursor of lanostanes, known to be produced by aerobic methanotrophs, some of which are outstanding among bacteria in having the capacity to produce steroids. In a Campanian seep limestone a suite of conspicuous secohexahydrobenzohopanes (-110 to -107 per mil) is found. These hopanoids probably represent early degradation products of seep-endemic aerobic methanotrophs. This interpretation is supported by the presence of "regular" hopanoids that can be discriminated from the unusual secohexahydrobenzohopanes by only moderately low delta C-13 values (-49 to -42 per mil). Structural and carbon isotope data reveal that aerobic methanotrophy is more common at ancient methane- seeps than previously noticed. Our data indicate that

  14. Chemical characterization of some aerobic liquids in CELSS

    NASA Technical Reports Server (NTRS)

    Madsen, Brooks C.

    1993-01-01

    Untreated aqueous soybean and wheat leachate and aerobically treated wheat leachate prepared from crop residues that are produced as a component of the Controlled Ecological Life Support System program designed to support long duration space missions were compared, and a general chemical characterization was accomplished. Solid phase extraction and high performance liquid chromatography were used to accomplish comparisons based on chromatographic and ultraviolet absorption properties of the components that are present. Specific compounds were not identified; however, general composition related to the initial presence of phenol-like compounds and their disappearance during aerobic treatment was explored.

  15. Effect of aerobic training and aerobic and resistance training on the inflammatory status of hypertensive older adults.

    PubMed

    Lima, Leandra G; Bonardi, José M T; Campos, Giulliard O; Bertani, Rodrigo F; Scher, Luria M L; Louzada-Junior, Paulo; Moriguti, Júlio C; Ferriolli, Eduardo; Lima, Nereida K C

    2015-08-01

    There is a relationship between high levels of inflammatory markers and low adhesion to the practice of physical activity in the older population. The objective of the present study was to compare the effect of two types of exercise programs, i.e., aerobic training and aerobic plus resistance training on the plasma levels of interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) of elderly hypertensive subjects. Hypertensive older volunteers in use of antihypertensive drugs were randomized to three groups: aerobic group (AG), resistance and aerobic group (RAG) and control group (CG). Training lasted 10 weeks, with sessions held three times a week. Blood samples were collected before training and 24 h after completion of the 30 sessions for the determination of serum IL-6 and TNF-α levels. Body mass index was obtained before and after 10 weeks. After intervention, BMI values were lower in AG and RAG compared to CG (p < 0.001), IL-6 was reduced in AG compared to CG (p = 0.04), and TNF-α levels were lower only in RAG compared to CG (p = 0.01). Concluding, both types of training were effective in reducing BMI values in hypertensive older subjects. Aerobic exercise produced the reduction of plasma IL-6 levels. However, the combination of aerobic and resistance exercise, which would be more indicated for the prevention of loss of functionality with aging, showed lower TNF-α mediator after training than control group and a greater fall of TNF-α levels associated to higher BMI reduction. PMID:25567682

  16. ENGINEERING AND ECONOMIC ASSESSMENT OF AUTOHEATED THERMOPHILIC AEROBIC DIGESTION WITH AIR AERATION

    EPA Science Inventory

    A major disadvantage of aerobic digestion is that it requires long detention times, particularly in colder climates, to insure adequate stabilization. Autoheated thermophilic aerobic digestion (ATAD) offers the potential to decrease the required detention time. ATAD takes advanta...

  17. Complete Genome Sequence of the Aerobic Marine Methanotroph Methylomonas methanica MC09

    SciTech Connect

    Boden, Rich; Cunliffe, Michael; Scanlan, Julie; Moussard, Helene; Kits, K. Dimitri; Klotz, Martin G; Jetten, MSM; Vuilleumier, Stephane; Han, James; Peters, Lin; Mikhailova, Natalia; Teshima, Hazuki; Tapia, Roxanne; Kyrpides, Nikos C; Ivanova, N; Pagani, Ioanna; Cheng, Jan-Fang; Goodwin, Lynne A.; Han, Cliff; Hauser, Loren John; Land, Miriam L; Lapidus, Alla L.; Lucas, Susan; Pitluck, Sam; Woyke, Tanja; Stein, Lisa Y.; Murrell, Collin

    2011-01-01

    Methylomonas methanica MC09 is a mesophilic, halotolerant, aerobic, methanotrophic member of the Gammaproteobacteria, isolated from coastal seawater. Here we present the complete genome sequence of this strain, the first available from an aerobic marine methanotroph.

  18. Helping Adults to Stay Physically Fit: Preventing Relapse Following Aerobic Exercise Training.

    ERIC Educational Resources Information Center

    Goodrick, G. Ken; And Others

    1984-01-01

    Long-term adherence to an aerobic exercise regime is a major problem among exercise program graduates. This article discusses the steps involved in developing relapse prevention treatment strategies for aerobic exercise programs. (JMK)

  19. Aerobic biodegradation of vinyl chloride in groundwater samples

    SciTech Connect

    Davis, J.W.; Carpenter, C.L. )

    1990-12-01

    Studies were conducted to examine the biodegradation of {sup 14}C-labeled vinyl chloride in samples taken from a shallow aquifer. Under aerobic conditions, vinyl chloride was readily degraded, with greater than 99% of the labeled material being degraded after 108 days and approximately 65% being mineralized to {sup 14}CO{sub 2}.

  20. Aerobic Fitness for the Severely and Profoundly Mentally Retarded.

    ERIC Educational Resources Information Center

    Bauer, Dan

    1981-01-01

    The booklet discusses the aerobic fitness capacities of severely/profoundly retarded students and discusses approaches for improving their fitness. An initial section describes a method for determining the student's present fitness level on the basis of computations of height, weight, blood pressure, resting pulse, and Barach Index and Crampton…

  1. Aerobic Capacity in Children and Adolescents with Cerebral Palsy

    ERIC Educational Resources Information Center

    Verschuren, Olaf; Takken, Tim

    2010-01-01

    This study described the aerobic capacity [VO[subscript 2peak] (ml/kg/min)] in contemporary children and adolescents with cerebral palsy (CP) using a maximal exercise test protocol. Twenty-four children and adolescents with CP classified at Gross Motor Functional Classification Scale (GMFCS) level I or level II and 336 typically developing…

  2. Aerobic Capacities of Early College High School Students

    ERIC Educational Resources Information Center

    Loflin, Jerry W.

    2014-01-01

    The Early College High School Initiative (ECHSI) was introduced in 2002. Since 2002, limited data, especially student physical activity data, have been published pertaining to the ECHSI. The purpose of this study was to examine the aerobic capacities of early college students and compare them to state and national averages. Early college students…

  3. Is Low-Impact Aerobic Dance an Effective Cardiovascular Workout?

    ERIC Educational Resources Information Center

    Williford, Henry N.; And Others

    1989-01-01

    Presents results of an investigation comparing energy cost and cardiovascular responses of aerobic dance routines performed at different intensity levels in varying amounts of energy expenditure. For low-impact dance to meet minimum guidelines suggested by the American College of Sports Medicine, it should be performed at high intensity. (SM)

  4. AEROBIC BIODEGRADABILITY AND TOXICITY OF NON-PETROLEUM OILS.

    EPA Science Inventory

    Vegetable oil spills are a widely known phenomenon, but are the least understood. These spills can be as devastating to the environment as petroleum oil spills. Previous laboratory research results have indicated that as vegetable oils degrade aerobically, the aqueous solutions b...

  5. Teaching Aerobic Cell Respiration Using the 5Es

    ERIC Educational Resources Information Center

    Patro, Edward T.

    2008-01-01

    The 5E teaching model provides a five step method for teaching science. While the sequence of the model is strictly linear, it does provide opportunities for the teacher to "revisit" prior learning before moving on. The 5E method is described as it relates to the teaching of aerobic cell respiration.

  6. The medically important aerobic actinomycetes: epidemiology and microbiology.

    PubMed Central

    McNeil, M M; Brown, J M

    1994-01-01

    The aerobic actinomycetes are soil-inhabiting microorganisms that occur worldwide. In 1888, Nocard first recognized the pathogenic potential of this group of microorganisms. Since then, several aerobic actinomycetes have been a major source of interest for the commercial drug industry and have proved to be extremely useful microorganisms for producing novel antimicrobial agents. They have also been well known as potential veterinary pathogens affecting many different animal species. The medically important aerobic actinomycetes may cause significant morbidity and mortality, in particular in highly susceptible severely immunocompromised patients, including transplant recipients and patients infected with human immunodeficiency virus. However, the diagnosis of these infections may be difficult, and effective antimicrobial therapy may be complicated by antimicrobial resistance. The taxonomy of these microorganisms has been problematic. In recent revisions of their classification, new pathogenic species have been recognized. The development of additional and more reliable diagnostic tests and of a standardized method for antimicrobial susceptibility testing and the application of molecular techniques for the diagnosis and subtyping of these microorganisms are needed to better diagnose and treat infected patients and to identify effective control measures for these unusual pathogens. We review the epidemiology and microbiology of the major medically important aerobic actinomycetes. Images PMID:7923055

  7. Aerobic Capacity and Anaerobic Power Levels of the University Students

    ERIC Educational Resources Information Center

    Taskin, Cengiz

    2016-01-01

    The aim of study was to analyze aerobic capacity and anaerobic power levels of the university students. Total forty university students who is department physical education and department business (age means; 21.15±1.46 years for male and age means; 20.55±1.79 years for female in department physical education), volunteered to participate in this…

  8. Relative importance of aerobic versus resistance training for healthy aging

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This review will focus on the importance of aerobic and resistance modes of physical activity for healthy aging as supported by findings in 2007. In line with public health recommendations, several studies in 2007 employed an exercise paradigm that combined both modes of physical activity. While a...

  9. Aerobic Digestion. Biological Treatment Process Control. Instructor's Guide.

    ERIC Educational Resources Information Center

    Klopping, Paul H.

    This unit on aerobic sludge digestion covers the theory of the process, system components, factors that affect the process performance, standard operational concerns, indicators of steady-state operations, and operational problems. The instructor's guide includes: (1) an overview of the unit; (2) lesson plan; (3) lecture outline (keyed to a set of…

  10. Aerobic and anaerobic cecal bacterial flora of commercially processed broilers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Differences in the bacterial flora of aerobic and anaerobic cultures of broiler ceca collected from a commercial poultry processing facility were determined. Bacterial isolates from cecal cultures were selected based on the ability of the bacteria to grow in media supplemented with lactate and succ...

  11. Characterization of aerobic ethanol productions in a computerized auxostat

    SciTech Connect

    Fraleigh, S.P.

    1989-01-01

    For many valuable bioproducts high productivity is associated with rapid growth. However, most continuous microbial cultures become unstable when the dilution rate is fixed near the value for maximum growth rate. The auxostat culture technique employs feedback control of a nutrient or metabolite to stabilize the biomass at its maximum potential growth rate. An auxostat device is therefore ideal for study of bioprocesses involving the overproduction of primary metabolites such as ethanol. Oxidoreductive transformations involving ethanol are utilized by Saccharomyces yeasts when normal respiration cannot satisfy energy needs. When rapid growth or other stress creates oxidoreductive conditions in aerobic Saccharomyces cultures, very high specific ethanol formation rates are established and biomass yield drops to levels more typical of anaerobic fermentation. Although the physiology is favorable, the potential for large-scale aerobic ethanol processes to compete with traditional anaerobic fermentations has not previously been assessed. In this study, a fully computerized auxostat device was constructed and used to characterize the specific and volumetric aerobic ethanol productivity of the yeast Saccharomyces cerevisiae. To divert substrate away from biomass and into product formation, aerobic cultures were stressed with variations of ionic balance (via extreme K{sup +} and H{sup +} setpoints) in the auxostat device. During growth with limiting K{sup +} concentrations, the goal of very low biomass yield was attained but the rate of ethanol production was poor. However, with excess K{sup +} the volumetric productivity reached 6.1 g/I,-h, a value that is comparable to optimized, continuous anaerobic cultures.

  12. Thirty-Three Years of Aerobic Exercise Adherence.

    ERIC Educational Resources Information Center

    Kasch, Frederick W.

    2001-01-01

    Followed 15 middle-aged men for 25-33 years while they participated in an aerobic exercise program. Adherence in the sample was 100 percent. Possible explanations for the adherence include program leadership, peer support, written evaluations and progress reports, emphasis on health, early and continued interest in sport and exercise, recognition…

  13. Growth of Campylobacter Incubated Aerobically in Media Supplemented with Peptones

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Growth of Campylobacter cultures incubated aerobically in media supplemented with peptones was studied, and additional experiments were conducted to compare growth of the bacteria in media supplemented with peptones to growth in media supplemented with fumarate-pyruvate-minerals-vitamins (FPMV). A b...

  14. AEROBIC BIODEGRADATION OF GASOLINE OXYGENATES MTBE AND TBA

    EPA Science Inventory

    MTBE degradation was investigated using a continuously stirred tank reactor (CSTR) with biomass retention (porous pot reactor) operated under aerobic conditions. MTBE was fed to the reactor at an influent concentration of 150 mg/l (1.70 mmol/l). A second identifical rector was op...

  15. Group Aquatic Aerobic Exercise for Children with Disabilities

    ERIC Educational Resources Information Center

    Fragala-Pinkham, Maria; Haley, Stephen M.; O'Neill, Margaret E.

    2008-01-01

    The effectiveness and safety of a group aquatic aerobic exercise program on cardiorespiratory endurance for children with disabilities was examined using an A-B study design. Sixteen children (11 males, five females) age range 6 to 11 years (mean age 9y 7mo [SD 1y 4mo]) participated in this twice-per-week program lasting 14 weeks. The children's …

  16. Identification of serum analytes and metabolites associated with aerobic capacity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Studies aimed at identifying serum markers of cellular metabolism (biomarkers) that are associated at baseline with aerobic capacity (V02 max) in young, healthy individuals have yet to be reported. Therefore, the goal of the present study was to use the standard chemistry screen and untargeted mass ...

  17. COMMERCIAL-SCALE AEROBIC-ANAEROBIC BIOREACTOR LANDFILL OPERATIONS

    EPA Science Inventory

    A sequential aerobic-anaerobic treatment system has been applied at a commercial scale (3,000 ton per day) municipal solid waste landfill in Kentucky, USA since 2001. In this system, the uppermost layer of landfilled waste is aerated and liquid waste including leachate, surface w...

  18. Measurement Agreement between Estimates of Aerobic Fitness in Youth: The Impact of Body Mass Index

    ERIC Educational Resources Information Center

    Saint-Maurice, Pedro F.; Welk, Gregory J.; Laurson, Kelly R.; Brown, Dale D.

    2014-01-01

    Purpose: The purpose of this study was to examine the impact of body mass index (BMI) on the agreement between aerobic capacity estimates from different Progressive Aerobic Cardiorespiratory Endurance Run (PACER) equations and the Mile Run Test. Method: The agreement between 2 different tests of aerobic capacity was examined on a large data set…

  19. Effects of dominant somatotype on aerobic capacity trainability

    PubMed Central

    Chaouachi, M; Chaouachi, A; Chamari, K; Chtara, M; Feki, Y; Amri, M; Trudeau, F

    2005-01-01

    Purpose: This study examined the association between dominant somatotype and the effect on aerobic capacity variables of individualised aerobic interval training. Methods: Forty one white North African subjects (age 21.4±1.3 years; V·o2max = 52.8±5.7 ml kg–1 min–1) performed three exercise tests 1 week apart (i) an incremental test on a cycle ergometer to determine V·o2max and V·o2 at the second ventilatory threshold (VT2); (ii) a VAM-EVAL track test to determine maximal aerobic speed (vV·o2max); and (iii) an exhaustive constant velocity test to determine time limit performed at 100% vV·o2max (tlim100). Subjects were divided into four somatometric groups: endomorphs-mesomorphs (Endo-meso; n = 9), mesomorphs (Meso; n = 11), mesomorphs-ectomorphs (Meso-ecto; n = 12), and ectomorphs (Ecto; n = 9). Subjects followed a 12 week training program (two sessions/week). Each endurance training session consisted of the maximal number of successive fractions for each subject. Each fraction consisted of one period of exercise at 100% of vV·o2max and one of active recovery at 60% of vV·o2max. The duration of each period was equal to half the individual tlim100 duration (153.6±39.7 s). After the training program, all subjects were re-evaluated for comparison with pre-test results. Results: Pre- and post-training data were grouped by dominant somatotype. Two way ANOVA revealed significant somatotype-aerobic training interaction effects (p<0.001) for improvements in vV·o2max, V·o2max expressed classically and according to allometric scaling, and V·o2 at VT2. There were significant differences among groups post-training: the Meso-ecto and the Meso groups showed the greatest improvements in aerobic capacity. Conclusion: The significant somatotype-aerobic training interaction suggests different trainability with intermittent and individualised aerobic training according to somatotype. PMID:16306506

  20. Characterization of a marine origin aerobic nitrifying-denitrifying bacterium.

    PubMed

    Zheng, Hai-Yan; Liu, Ying; Gao, Xi-Yan; Ai, Guo-Min; Miao, Li-Li; Liu, Zhi-Pei

    2012-07-01

    The bacterial strain F6 was isolated from a biological aerated filter that is used for purifying recirculating water in a marine aquaculture system and was identified as Marinobacter sp. based on the analysis of its 16S rRNA gene sequence. Strain F6 showed efficient aerobic denitrifying ability. One hundred percent of nitrates and 73.10% of nitrites were removed, and the total nitrogen (TN) removal rates reached 50.08% and 33.03% under a high nitrate and nitrite concentration in the medium, respectively. N(2)O and (15)N(2), as revealed by GC-MS and GC-IRMS, were the products of aerobic denitrification. Factors affecting the growth and aerobic denitrifying performance of strain F6 were investigated. The results showed that the optimum aerobic denitrification conditions for strain F6 were the presence of sodium succinate as a carbon source, a C/N ratio of 15, salinity ranging from 32-35 g/L of NaCl, incubation temperature of 30°C, an initial pH of 7.5, and rotation speed of 150 rpm [dissolved oxygen (DO) 6.75 mg/L]. In addition, strain F6 was confirmed to be a heterotrophic nitrifier through its NO(2)(-) generation and 25.96% TN removal when NH(4)(+) was used as the sole N source. Therefore, strain F6, the first reported member of genus Marinobacter with aerobic heterotrophic nitrifying-denitrifying ability, is an excellent candidate for facilitating simultaneous nitrification and denitrification (SND) in industry and aquaculture wastewater. PMID:22578593

  1. Aerobic exercise augments muscle transcriptome profile of resistance exercise.

    PubMed

    Lundberg, Tommy R; Fernandez-Gonzalo, Rodrigo; Tesch, Per A; Rullman, Eric; Gustafsson, Thomas

    2016-06-01

    Recent reports suggest that aerobic exercise may boost the hypertrophic response to short-term resistance training. This study explored the effects of an acute aerobic exercise bout on the transcriptional response to subsequent resistance exercise. Ten moderately trained men performed ∼45 min cycling on one leg followed by 4 × 7 maximal knee extensions for each leg, 15 min later. Thus, one limb performed aerobic and resistance exercise (AE + RE) while the opposing leg did resistance exercise only (RE). Biopsies were obtained from the vastus lateralis muscle of each leg 3 h after the resistance exercise bout. Using DNA microarray, we analyzed differences [≥1.5-fold, false discovery rate (FDR) ≤10%] in gene expression profiles for the two modes of exercise. There were 176 genes up (127)- or downregulated (49) by AE + RE compared with RE. Among the most significant differentially expressed genes were established markers for muscle growth and oxidative capacity, novel cytokines, transcription factors, and micro-RNAs (miRNAs). The most enriched functional categories were those linked to carbohydrate metabolism and transcriptional regulation. Upstream analysis revealed that vascular endothelial growth factor, cAMP-response element-binding protein, Tet methylcytosine dioxygenase, and mammalian target of rapamycin were regulators highly activated by AE + RE, whereas JnK, NF-κβ, MAPK, and several miRNAs were inhibited. Thus, aerobic exercise alters the skeletal muscle transcriptional signature of resistance exercise to initiate important gene programs promoting both myofiber growth and improved oxidative capacity. These results provide novel insight into human muscle adaptations to diverse exercise modes and offer the very first genomic basis explaining how aerobic exercise may augment, rather than compromise, muscle growth induced by resistance exercise. PMID:27101291

  2. Comparing Acute Effects of a Nano-TiO2 Pigment on Cosmopolitan Freshwater Phototrophic Microbes Using High-Throughput Screening

    PubMed Central

    Binh, Chu Thi Thanh; Peterson, Christopher G.; Tong, Tiezheng; Gray, Kimberly A.; Gaillard, Jean-François; Kelly, John J.

    2015-01-01

    Production of titanium-dioxide nanomaterials (nano-TiO2) is increasing, leading to potential risks associated with unintended release of these materials into aquatic ecosystems. We investigated the acute effects of nano-TiO2 on metabolic activity and viability of algae and cyanobacteria using high-throughput screening. The responses of three diatoms (Surirella angusta, Cocconeis placentula, Achnanthidium lanceolatum), one green alga (Scenedesmus quadricauda), and three cyanobacteria (Microcystis aeruginosa, Gloeocapsa sp., Synechococcus cedrorum) to short-term exposure (15 to 60 min) to a common nano-TiO2 pigment (PW6; average crystallite size 81.5 nm) with simulated solar illumination were assessed. Five concentrations of nano-TiO2 (0.5, 2.5, 5, 10, and 25 mg L-1) were tested and a fluorescent reporter (fluorescein diacetate) was used to assess metabolic activity. Algae were sensitive to nano-TiO2, with all showing decreased metabolic activity after 30-min exposure to the lowest tested concentration. Microscopic observation of algae revealed increased abundance of dead cells with nano-TiO2 exposure. Cyanobacteria were less sensitive to nano-TiO2 than algae, with Gloeocapsa showing no significant decrease in activity with nano-TiO2 exposure and Synechococcus showing an increase in activity. These results suggest that nanomaterial contamination has the potential to alter the distribution of phototrophic microbial taxa within freshwater ecosystems. The higher resistance of cyanobacteria could have significant implications as cyanobacteria represent a less nutritious food source for higher trophic levels and some cyanobacteria can produce toxins and contribute to harmful algal blooms. PMID:25923116

  3. Comparing Acute Effects of a Nano-TiO2 Pigment on Cosmopolitan Freshwater Phototrophic Microbes Using High-Throughput Screening.

    PubMed

    Binh, Chu Thi Thanh; Peterson, Christopher G; Tong, Tiezheng; Gray, Kimberly A; Gaillard, Jean-François; Kelly, John J

    2015-01-01

    Production of titanium-dioxide nanomaterials (nano-TiO2) is increasing, leading to potential risks associated with unintended release of these materials into aquatic ecosystems. We investigated the acute effects of nano-TiO2 on metabolic activity and viability of algae and cyanobacteria using high-throughput screening. The responses of three diatoms (Surirella angusta, Cocconeis placentula, Achnanthidium lanceolatum), one green alga (Scenedesmus quadricauda), and three cyanobacteria (Microcystis aeruginosa, Gloeocapsa sp., Synechococcus cedrorum) to short-term exposure (15 to 60 min) to a common nano-TiO2 pigment (PW6; average crystallite size 81.5 nm) with simulated solar illumination were assessed. Five concentrations of nano-TiO2 (0.5, 2.5, 5, 10, and 25 mg L-1) were tested and a fluorescent reporter (fluorescein diacetate) was used to assess metabolic activity. Algae were sensitive to nano-TiO2, with all showing decreased metabolic activity after 30-min exposure to the lowest tested concentration. Microscopic observation of algae revealed increased abundance of dead cells with nano-TiO2 exposure. Cyanobacteria were less sensitive to nano-TiO2 than algae, with Gloeocapsa showing no significant decrease in activity with nano-TiO2 exposure and Synechococcus showing an increase in activity. These results suggest that nanomaterial contamination has the potential to alter the distribution of phototrophic microbial taxa within freshwater ecosystems. The higher resistance of cyanobacteria could have significant implications as cyanobacteria represent a less nutritious food source for higher trophic levels and some cyanobacteria can produce toxins and contribute to harmful algal blooms. PMID:25923116

  4. Effects of Aerobic Exercise Based upon Heart Rate at Aerobic Threshold in Obese Elderly Subjects with Type 2 Diabetes

    PubMed Central

    Donini, Lorenzo Maria

    2015-01-01

    In obese diabetic subjects, a correct life style, including diet and physical activity, is part of a correct intervention protocol. Thus, the aim of this study was to evaluate the effects of aerobic training intervention, based on heart rate at aerobic gas exchange threshold (AerTge), on clinical and physiological parameters in obese elderly subjects with type 2 diabetes (OT2DM). Thirty OT2DM subjects were randomly assigned to an intervention (IG) or control group (CG). The IG performed a supervised aerobic exercise training based on heart rate at AerTge whereas CG maintained their usual lifestyle. Anthropometric measures, blood analysis, peak oxygen consumption (V˙O2peak), metabolic equivalent (METpeak), work rate (WRpeak), and WRAerTge were assessed at baseline and after intervention. After training, patients enrolled in the IG had significantly higher (P < 0.001) V˙O2peak, METpeak, WRpeak, and WRAerTge and significantly lower (P < 0.005) weight, BMI, %FM, and waist circumference than before intervention. Both IG and CG subjects had lower glycated haemoglobin levels after intervention period. No significant differences were found for all the other parameters between pre- and posttraining and between groups. Aerobic exercise prescription based upon HR at AerTge could be a valuable physical intervention tool to improve the fitness level and metabolic equilibrium in OT2DM patients. PMID:26089890

  5. Adaptation to Oxygen

    PubMed Central

    Hassani, Bahia Khalfaoui; Steunou, Anne-Soisig; Liotenberg, Sylviane; Reiss-Husson, Françoise; Astier, Chantal; Ouchane, Soufian

    2010-01-01

    The appearance of oxygen in the Earth's atmosphere via oxygenic photosynthesis required strict anaerobes and obligate phototrophs to cope with the presence of this toxic molecule. Here we show that in the anoxygenic phototroph Rubrivivax gelatinosus, the terminal oxidases (cbb3, bd, and caa3) expand the range of ambient oxygen tensions under which the organism can initiate photosynthesis. Unlike the wild type, the cbb3−/bd− double mutant can start photosynthesis only in deoxygenated medium or when oxygen is removed, either by sparging cultures with nitrogen or by co-inoculation with strict aerobes bacteria. In oxygenated environments, this mutant survives nonphotosynthetically until the O2 tension is reduced. The cbb3 and bd oxidases are therefore required not only for respiration but also for reduction of the environmental O2 pressure prior to anaerobic photosynthesis. Suppressor mutations that restore respiration simultaneously restore photosynthesis in nondeoxygenated medium. Furthermore, induction of photosystem in the cbb3− mutant led to a highly unstable strain. These results demonstrate that photosynthetic metabolism in environments exposed to oxygen is critically dependent on the O2-detoxifying action of terminal oxidases. PMID:20335164

  6. RESISTANCE TRAINING AS A PRECONDITIONING STRATEGY FOR ENHANCING AEROBIC EXERCISE TRAINING OUTCOMES IN COPD

    PubMed Central

    Covey, Margaret K.; Collins, Eileen G.; Reynertson, Sandra I.; Dilling, Daniel F.

    2014-01-01

    Purpose Aerobic exercise training is a recognized approach for improving functional capacity in COPD. People with greater disease severity often have difficulty achieving higher aerobic exercise training intensity. The effects of resistance training prior to aerobic training were examined to determine if this sequential approach was associated with greater gains in functional status than aerobic training alone or concurrent aerobic and resistance training. Methods Patients were randomized to: 1) sequential resistance then aerobic training (RT-then-AT) (8 weeks resistance training followed by 8 weeks aerobic exercise training), 2) control group (CE-then-AT+RT) (8 weeks of ‘sham’ training followed by 8 weeks concurrent aerobic and resistance training), 3) control group (CE-then-AT) (8 weeks ‘sham’ training followed by 8 weeks aerobic training). Outcomes were assessed at study entry, after week 8, and after week 16: aerobic exercise performance; muscle strength and endurance. Results 75 patients completed training: FEV1 %pred 40±10, V̇O2peak %predicted, 71±22, fat-free mass index 19.5±3.1. RT-then-AT had greater acquisition of peripheral muscle endurance than CE-then-AT+RT and CE-then-AT, but improvements in aerobic exercise performance were similar. Improvements in muscle strength were similar between RT-then-AT and CE-then-AT+RT. Sarcopenia was associated with poorer attendance, and lower aerobic and resistance training volumes. Conclusion Although the sequential approach to resistance and aerobic training yielded a greater increase in muscle endurance and higher resistance training volume compared to concurrent resistance and aerobic training, other training outcomes were similar between the two groups, thus the sequential approach is not clearly superior to the concurrent approach in severe COPD. ClinicalTrials.gov Identifier NCT01058213. PMID:24958605

  7. Field assessment of semi-aerobic condition and the methane correction factor for the semi-aerobic landfills provided by IPCC guidelines

    SciTech Connect

    Jeong, Sangjae; Nam, Anwoo; Yi, Seung-Muk; Kim, Jae Young

    2015-02-15

    Highlights: • CH{sub 4}/CO{sub 2} and CH{sub 4} + CO{sub 2}% are proposed as indices to evaluate semi-aerobic landfills. • A landfill which CH{sub 4}/CO{sub 2} > 1.0 is difficult to be categorized as semi-aerobic landfill. • Field conditions should be carefully investigated to determine landfill types. • The MCF default value for semi-aerobic landfills underestimates the methane emissions. - Abstract: According to IPCC guidelines, a semi-aerobic landfill site produces one-half of the amount of CH{sub 4} produced by an equally-sized anaerobic landfill site. Therefore categorizing the landfill type is important on greenhouse gas inventories. In order to assess semi-aerobic condition in the sites and the MCF value for semi-aerobic landfill, landfill gas has been measured from vent pipes in five semi-aerobically designed landfills in South Korea. All of the five sites satisfied requirements of semi-aerobic landfills in 2006 IPCC guidelines. However, the ends of leachate collection pipes which are main entrance of air in the semi-aerobic landfill were closed in all five sites. The CH{sub 4}/CO{sub 2} ratio in landfill gas, indicator of aerobic and anaerobic decomposition, ranged from 1.08 to 1.46 which is higher than the values (0.3–1.0) reported for semi-aerobic landfill sites and is rather close to those (1.0–2.0) for anaerobic landfill sites. The low CH{sub 4} + CO{sub 2}% in landfill gas implied air intrusion into the landfill. However, there was no evidence that air intrusion has caused by semi-aerobic design and operation. Therefore, the landfills investigated in this study are difficult to be classified as semi-aerobic landfills. Also MCF of 0.5 may significantly underestimate methane emissions compared to other researches. According to the carbon mass balance analyses, the higher MCF needs to be proposed for semi-aerobic landfills. Consequently, methane emission estimate should be based on field evaluation for the semi-aerobically designed landfills.

  8. Axenic aerobic biofilms inhibit corrosion of copper and aluminum.

    PubMed

    Jayaraman, A; Ornek, D; Duarte, D A; Lee, C C; Mansfeld, F B; Wood, T K

    1999-11-01

    The corrosion behavior of unalloyed copper and aluminum alloy 2024 in modified Baar's medium has been studied with continuous reactors using electrochemical impedance spectroscopy. An axenic aerobic biofilm of either Pseudomonas fragi K or Bacillus brevis 18 was able to lessen corrosion as evidenced by a consistent 20-fold increase in the low-frequency impedance value of copper as well as by a consistent four- to seven-fold increase in the polarization resistance of aluminum 2024 after six days exposure compared to sterile controls. This is the first report of axenic aerobic biofilms inhibiting generalized corrosion of copper and aluminum. Addition of the representative sulfate-reducing bacterium (SRB) Desulfovibrio vulgaris (to simulate consortia corrosion behavior) to either the P. fragi K or B. brevis 18 protective biofilm on copper increased the corrosion to that of the sterile control unless antibiotic (ampicillin) was added to inhibit the growth of SRB in the biofilm. PMID:10616712

  9. [Fluorescence fingerprint transformation of municipal wastewater caused by aerobic treatment].

    PubMed

    Wu, Jing; Cui, Shuo; Xie, Chao-bo; Cao, Zhi-ping; Chen, Mao-fu; Lü, Yan-li

    2011-12-01

    The conventional parameters such as COD and BOD only could represent information about total organic content. Fluorescence spectrum can display organic composition and it is unique for each sample, so it is referred as "fluorescence fingerprint". In the present study transformation of excitation-emission matrix of municipal wastewater with sewage as major components after aerobic treatment was investigated and then the zones of biodegradable and non-biodegradable organic matters were figured out: the fluorescence at excitation wavelength/emission wavelength of about 280/340 nm and 225/240 nm derived from biodegradable organics and those of the zone of excitation wavelength above 300 nm and the zone of excitation wavelength below 300 nm and emission wavelength above 400 nm were mainly related with non-biodegradable organics. The above-mentioned results indicated that fluorescence fingerprint could be used to evaluate the performance and instruct design and operation of aerobic systems. PMID:22295782

  10. Aerobic scope explains individual variation in feeding capacity

    PubMed Central

    Auer, Sonya K.; Salin, Karine; Anderson, Graeme J.; Metcalfe, Neil B.

    2015-01-01

    Links between metabolism and components of fitness such as growth, reproduction and survival can depend on food availability. A high standard metabolic rate (SMR; baseline energy expenditure) or aerobic scope (AS; the difference between an individual's maximum and SMR) is often beneficial when food is abundant or easily accessible but can be less important or even disadvantageous when food levels decline. While the mechanisms underlying these context-dependent associations are not well understood, they suggest that individuals with a higher SMR or AS are better able to take advantage of high food abundance. Here we show that juvenile brown trout (Salmo trutta) with a higher AS were able to consume more food per day relative to individuals with a lower AS. These results help explain why a high aerobic capacity can improve performance measures such as growth rate at high but not low levels of food availability. PMID:26556902

  11. Aerobic scope explains individual variation in feeding capacity.

    PubMed

    Auer, Sonya K; Salin, Karine; Anderson, Graeme J; Metcalfe, Neil B

    2015-11-01

    Links between metabolism and components of fitness such as growth, reproduction and survival can depend on food availability. A high standard metabolic rate (SMR; baseline energy expenditure) or aerobic scope (AS; the difference between an individual's maximum and SMR) is often beneficial when food is abundant or easily accessible but can be less important or even disadvantageous when food levels decline. While the mechanisms underlying these context-dependent associations are not well understood, they suggest that individuals with a higher SMR or AS are better able to take advantage of high food abundance. Here we show that juvenile brown trout (Salmo trutta) with a higher AS were able to consume more food per day relative to individuals with a lower AS. These results help explain why a high aerobic capacity can improve performance measures such as growth rate at high but not low levels of food availability. PMID:26556902

  12. Aerobic and microaerophilic actinomycetes of typical agropeat and peat soils

    NASA Astrophysics Data System (ADS)

    Zenova, G. M.; Gryadunova, A. A.; Pozdnyakov, A. I.; Zvyagintsev, D. G.

    2008-02-01

    A high number (from tens of thousands to millions of CFU/g of soil) of actinomycetes and a high diversity of genera were found in typical peat and agropeat soils. Agricultural use increases the number and diversity of the actinomycete complexes of the peat soils. In the peat soils, the actinomycete complex is represented by eight genera: Streptomyces, Micromonospora, Streptosporangium, Actinomadura, Microbispora, Saccharopolyspora, Saccharomonospora, and Microtetraspora. A considerable share of sporangial forms in the actinomycete complex of the peat soils not characteristic of the zonal soils was revealed. The number of actinomycetes that develop under aerobic conditions is smaller by 10-100 times than that of aerobic forms in the peat soils. Among the soil actinomycetes of the genera Streptomyces, Micromonospora, Streptosporangium, Actinomadura, Microbispora, and Microtetraspora, the microaerophilic forms were found; among the Saccharopolyspora and Saccharomonospora, no microaerophilic representatives were revealed.

  13. C4-Dicarboxylate Utilization in Aerobic and Anaerobic Growth.

    PubMed

    Unden, Gottfried; Strecker, Alexander; Kleefeld, Alexandra; Kim, Ok Bin

    2016-06-01

    C4-dicarboxylates and the C4-dicarboxylic amino acid l-aspartate support aerobic and anaerobic growth of Escherichia coli and related bacteria. In aerobic growth, succinate, fumarate, D- and L-malate, L-aspartate, and L-tartrate are metabolized by the citric acid cycle and associated reactions. Because of the interruption of the citric acid cycle under anaerobic conditions, anaerobic metabolism of C4-dicarboxylates depends on fumarate reduction to succinate (fumarate respiration). In some related bacteria (e.g., Klebsiella), utilization of C4-dicarboxylates, such as tartrate, is independent of fumarate respiration and uses a Na+-dependent membrane-bound oxaloacetate decarboxylase. Uptake of the C4-dicarboxylates into the bacteria (and anaerobic export of succinate) is achieved under aerobic and anaerobic conditions by different sets of secondary transporters. Expression of the genes for C4-dicarboxylate metabolism is induced in the presence of external C4-dicarboxylates by the membrane-bound DcuS-DcuR two-component system. Noncommon C4-dicarboxylates like l-tartrate or D-malate are perceived by cytoplasmic one-component sensors/transcriptional regulators. This article describes the pathways of aerobic and anaerobic C4-dicarboxylate metabolism and their regulation. The citric acid cycle, fumarate respiration, and fumarate reductase are covered in other articles and discussed here only in the context of C4-dicarboxylate metabolism. Recent aspects of C4-dicarboxylate metabolism like transport, sensing, and regulation will be treated in more detail. This article is an updated version of an article published in 2004 in EcoSal Plus. The update includes new literature, but, in particular, the sections on the metabolism of noncommon C4-dicarboxylates and their regulation, on the DcuS-DcuR regulatory system, and on succinate production by engineered E. coli are largely revised or new. PMID:27415771

  14. Aerobic Methane Oxidation in Alaskan Lakes Along a Latitudinal Transect

    NASA Astrophysics Data System (ADS)

    Martinez-Cruz, K. C.; Sepulveda-Jauregui, A.; Walter Anthony, K. M.; Anthony, P.; Thalasso, F.

    2013-12-01

    Karla Martinez-Cruz* **, Armando Sepulveda-Jauregui*, Katey M. Walter Anthony*, Peter Anthony*, and Frederic Thalasso**. * Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, Alaska. ** Biotechnology and Bioengineering Department, Cinvestav, Mexico city, D. F., Mexico. Methane (CH4) is the third most important greenhouse gas in the atmosphere, after carbon dioxide and water vapor. Boreal lakes play an important role in the current global warming by contributing as much as 6% of global atmospheric CH4 sources annually. On the other hand, aerobic methane oxidation (methanotrophy) in lake water is a fundamental process in global methane cycling that reduces the amount of CH4 emissions to the atmosphere. Several environmental factors affect aerobic methane oxidation in the water column both directly and indirectly, including concentration of CH4 and O2, temperature and carbon budgets of lakes. We analyzed the potential of aerobic methane oxidation (PMO) rates in incubations of water collected from 30 Alaskan lakes along a north-south transect during winter and summer 2011. Our findings showed an effect of CH4 and O2 concentrations, temperature and yedoma thawing permafrost on PMO activity in the lake water. The highest PMO rates were observed in summer by lakes situated on thawing yedoma permafrost, most of them located in the interior of Alaska. We also estimated that 60-80% of all CH4 produced in Alaskan lakes could be taken up by methanotrophs in the lake water column, showing the significant influence of aerobic methane oxidation of boreal lakes to the global CH4 budget.

  15. Aerobic microorganism for the degradation of chlorinated aliphatic hydrocarbons

    DOEpatents

    Fliermans, Carl B.

    1989-01-01

    A chlorinated aliphatic hydrocarbon-degrading microorganism, having American Type Culture Collection accession numbers ATCC 53570 and 53571, in a biologically pure culture aseptically collected from a deep subsurface habitat and enhanced, mineralizes trichloroethylene and tetrachloroethylene to HCl, H.sub.2 O and Co.sub.2 under aerobic conditions stimulated by methane, acetate, methanol, tryptone-yeast extract, propane and propane-methane.

  16. Intensity Thresholds for Aerobic Exercise–Induced Hypoalgesia

    PubMed Central

    Naugle, Kelly M.; Naugle, Keith E.; Fillingim, Roger B.; Samuels, Brian; Riley, Joseph L.

    2014-01-01

    Despite many studies investigating exercise-induced hypoalgesia, there is limited understanding of the optimal intensity of aerobic exercise in producing hypoalgesic effects across different types of pain stimuli. Given that not all individuals are willing or capable of engaging in high intensity aerobic exercise, whether moderate intensity aerobic exercise is associated with a hypoalgesic response and whether this response generalizes to multiple pain induction techniques needs to be substantiated. Purpose This study’s purpose is to test for differences in the magnitude of pressure and heat pain modulation induced by moderate (MAE) and vigorous (VAE) intensity aerobic exercise. Methods Twelve healthy young males and 15 females completed one training session and three testing sessions consisting of 25 minutes of either 1) stationary cycling at 70% heart rate reserve (HRR), 2) stationary cycling at 50% HRR, or 3) quiet rest (control). Pain testing was conducted on both forearms prior to and immediately following each condition and included the following tests: pressure pain thresholds (PPT), suprathreshold pressure pain test, static continuous heat test, and repetitive pulse heat pain test. Repeated measures ANOVAs were conducted on each pain measure. Results VAE and MAE reduced pain ratings during static continuous heat stimuli and repetitive heat pulse stimuli, with VAE producing larger effects. VAE also increased PPTs, while neither exercise influenced suprathreshold pressure pain ratings. Conclusion These results suggest that MAE is capable of producing a hypoalgesic effect using continuous and repetitive pulse heat stimuli. However, a dose-response effect was evident as VAE produced larger effects than MAE. PMID:24002342

  17. Considerations in prescribing preflight aerobic exercise for astronauts.

    PubMed

    Frey, M A

    1987-10-01

    Many human responses to the weightless environment have been documented from actual spaceflights. These include physiological effects on the nervous system, cardiovascular system and fluid balance, and the musculoskeletal system, as well as psychological effects. Simulations on Earth have added to our knowledge about the physiology of weightlessness. Early data on orthostatic intolerance after real and simulated spaceflight led some scientists to discourage a high level of aerobic fitness for astronauts. They believed it was detrimental to orthostatic tolerance on return to Earth. However, most of the data available today do not support this contention. Furthermore, aerobic fitness is beneficial to cardiovascular function and mental performance. Therefore, it may be important in performing extra-vehicular activities during flight. Some astronauts claim exercise enhances their feeling of well-being and self image. And, although the cardiovascular system and exercise performance may recover more slowly after flight to preflight levels when fitness level prior to flight is high, the musculoskeletal system may recover more rapidly. Research is needed to determine optimal levels of aerobic training for performing tasks in flight, maintaining health and well-being during flight, and assuring satisfactory recovery on return to Earth. PMID:3314852

  18. Aerobic fitness and orthostatic tolerance: Evidence against an association

    NASA Technical Reports Server (NTRS)

    Ebert, Thomas J.

    1994-01-01

    This presentation will focus on only one side of the debate as to whether high levels of aerobic fitness have a deleterious effect on tolerance to gravitational stress. This issue was raised in the early 1970's as a result of two research publications. The first work investigated the carotid sinus baroreflex of humans with an airtight chamber that surrounded the head and neck. The steady-state reflex changes in blood pressure that were recorded 3 minutes after application of the head and neck stimuli, were attenuated in an athletic group compared to a sedentary group of volunteers. A second report in the NASA literature indicated that five endurance-trained runners were less tolerant to LBNP than five nonrunners. These early research findings have stimulated a considerable amount of interest that has lead to a growing number of research efforts seeking an association between aerobic fitness and orthostatic tolerance in humans. I will briefly review some of the more pertinent published research information which suggests that there is no relationship between aerobic fitness and orthostatic tolerance in humans.

  19. Aerobic and anaerobic growth of Paracoccus denitrificans on methanol.

    PubMed

    Bamforth, C W; Quayle, J R

    1978-10-01

    1. The dye-linked methanol dehydrogenase from Paracoccus denitrificans grown aerobically on methanol has been purified and its properties compared with similar enzymes from other bacteria. It was shown to be specific and to have high affinity for primary alcohols and formaldehyde as substrate, ammonia was the best activator and the enzyme could be linked to reduction of phenazine methosulphate. 2. Paracoccus denitrificans could be grown anaerobically on methanol, using nitrate or nitrite as electron acceptor. The methanol dehydrogenase synthesized under these conditions could not be differentiated from the aerobically-synthesized enzyme. 3. Activities of methanol dehydrogenase, formaldehyde dehydrogenase, formate dehydrogenase, nitrate reductase and nitrite reductase were measured under aerobic and anaerobic growth conditions. 4. Difference spectra of reduced and oxidized cytochromes in membrane and supernatant fractions of methanol-grown P. denitrificans were measured. 5. From the results of the spectral and enzymatic analyses it has been suggested that anaerobic growth on methanol/nitrate is made possible by reduction of nitrate to nitrite using electrons derived from the pyridine nucleotide-linked dehydrogenations of formaldehyde and formate, the nitrite so produced then functioning as electron acceptor for methanol dehydrogenase via cytochrome c and nitrite reductase. PMID:718372

  20. Decomposition of organic waste products under aerobic and anaerobic conditions

    SciTech Connect

    Gale, P.M.

    1988-01-01

    The objectives of this research were to determine the kinetics of C and N mineralization under aerobic and anaerobic conditions. These parameters were then used to verify the simulation model, DECOMPOSITION, for the anaerobic system. Incubation experiments were conducted to compare the aerobic and anaerobic decomposition of alfalfa (Medicago sativa L.), a substrate with a low C:N ratio. Under anaerobic conditions the net mineralization of N occurred more rapidly than that under aerobic conditions. However, the rate of C mineralization as measured by CO{sub 2} evolution was much lower. For the anaerobic decomposition of alfalfa, C mineralization was best described as the sum of the CO{sub 2} and CH{sub 4} evolved plus the water soluble organic C formed. The kinetics of C mineralization, as determined by this approach, were used to successfully predict the rate and amount of N mineralization from alfalfa undergoing anaerobic decomposition. The decomposition of paper mill sludge, a high C:N ratio substrate, was also evaluated.

  1. Aerobic and anaerobic exercise training in obese adults

    PubMed Central

    Al Saif, Amer; Alsenany, Samira

    2015-01-01

    [Purpose] Obesity is a global health problem and is associated with a multitude of complications. This study was designed to determine changes in cardiopulmonary functions after aerobic and anaerobic exercise training in obese subjects. [Subjects and Methods] Forty obese subjects, whose ages ranged between 18 and 25 years, were divided into 2 equal groups: group A received aerobic exercise training in addition to dietary measures, and group B received anaerobic exercise training for 3 months in addition to dietary measures. Measurements of systolic blood pressure, diastolic blood pressure, heart rate, maximum voluntary ventilation, maximal oxygen consumption, and body mass index were obtained for both groups before and after the exercise program. [Results] The mean body mass index, systolic blood pressure, diastolic blood pressure, heart rate, and maximal oxygen consumption decreased significantly, whereas the mean maximum voluntary ventilation increased significantly after treatment in group A. The mean maximum voluntary ventilation also increased significantly after treatment in group B. There were significant differences between the mean levels of the investigated parameters in groups A and B after treatment. [Conclusion] Aerobic exercise reduces weight and improves cardiopulmonary fitness in obese subjects better than anaerobic exercise. PMID:26180300

  2. Obesity promotes aerobic glycolysis in prostate cancer cells.

    PubMed

    Cavazos, David A; deGraffenried, Matthew J; Apte, Shruti A; Bowers, Laura W; Whelan, Kaitlin A; deGraffenried, Linda A

    2014-01-01

    Obesity is the leading preventable comorbidity associated with increased prostate cancer-related recurrence and mortality. Epidemiological and clinical studies indicate that a body mass index >30 is associated with increased oxidative DNA damage within the prostate gland and increased prostate cancer-related mortality. Here we provide evidence that obesity promotes worse clinical outcome through induction of metabolic abnormalities known to promote genotoxic stress. We have previously reported that blood serum derived from obese mice may enhance the proliferative and invasive potential of human prostate cancer cell lines ex vivo. Here we show that a 1-h exposure of LNCaP or PacMetUT1 prostate cancer cell lines and nonmalignant RWPE-1 prostate epithelial cells to 2% serum from obese mice induces markers of aerobic glycolysis relative to those exposed to serum from nonobese mice. This metabolic change was correlated with accumulation of reactive oxygen species (ROS) and increased frequency of DNA double-strand breaks. Interestingly, N-tert-Butylhydroxylamine, an antioxidant, significantly suppressed markers of aerobic glycolysis in the cells exposed to the blood serum of obese mice, suggesting that ROS contributes to a metabolic shift toward aerobic glycolysis. Here we describe obesity-induced changes in key metabolic markers that impact prostate cancer cell progression and explore the role of antioxidants in ameliorating these effects. PMID:25264717

  3. Aerobic Microbial Respiration In Oceanic Oxygen Minimum Zones

    PubMed Central

    Kalvelage, Tim; Lavik, Gaute; Jensen, Marlene M.; Revsbech, Niels Peter; Löscher, Carolin; Schunck, Harald; Desai, Dhwani K.; Hauss, Helena; Kiko, Rainer; Holtappels, Moritz; LaRoche, Julie; Schmitz, Ruth A.; Graco, Michelle I.; Kuypers, Marcel M. M.

    2015-01-01

    Oxygen minimum zones are major sites of fixed nitrogen loss in the ocean. Recent studies have highlighted the importance of anaerobic ammonium oxidation, anammox, in pelagic nitrogen removal. Sources of ammonium for the anammox reaction, however, remain controversial, as heterotrophic denitrification and alternative anaerobic pathways of organic matter remineralization cannot account for the ammonium requirements of reported anammox rates. Here, we explore the significance of microaerobic respiration as a source of ammonium during organic matter degradation in the oxygen-deficient waters off Namibia and Peru. Experiments with additions of double-labelled oxygen revealed high aerobic activity in the upper OMZs, likely controlled by surface organic matter export. Consistently observed oxygen consumption in samples retrieved throughout the lower OMZs hints at efficient exploitation of vertically and laterally advected, oxygenated waters in this zone by aerobic microorganisms. In accordance, metagenomic and metatranscriptomic analyses identified genes encoding for aerobic terminal oxidases and demonstrated their expression by diverse microbial communities, even in virtually anoxic waters. Our results suggest that microaerobic respiration is a major mode of organic matter remineralization and source of ammonium (~45-100%) in the upper oxygen minimum zones, and reconcile hitherto observed mismatches between ammonium producing and consuming processes therein. PMID:26192623

  4. Posttranscriptional Control of T Cell Effector Function by Aerobic Glycolysis

    PubMed Central

    Chang, Chih-Hao; Curtis, Jonathan D.; Maggi, Leonard B.; Faubert, Brandon; Villarino, Alejandro V.; O’Sullivan, David; Huang, Stanley Ching-Cheng; van der Windt, Gerritje J.W.; Blagih, Julianna; Qiu, Jing; Weber, Jason D.; Pearce, Edward J.; Jones, Russell G.; Pearce, Erika L.

    2013-01-01

    SUMMARY A “switch” from oxidative phosphorylation (OXPHOS) to aerobic glycolysis is a hallmark of T cell activation and is thought to be required to meet the metabolic demands of proliferation. However, why proliferating cells adopt this less efficient metabolism, especially in an oxygen-replete environment, remains incompletely understood. We show here that aerobic glycolysis is specifically required for effector function in T cells but that this pathway is not necessary for proliferation or survival. When activated T cells are provided with costimulation and growth factors but are blocked from engaging glycolysis, their ability to produce IFN-γ is markedly compromised. This defect is translational and is regulated by the binding of the glycolysis enzyme GAPDH to AU-rich elements within the 3′ UTR of IFN-γ mRNA. GAPDH, by engaging/disengaging glycolysis and through fluctuations in its expression, controls effector cytokine production. Thus, aerobic glycolysis is a metabolically regulated signaling mechanism needed to control cellular function. PMID:23746840

  5. Transcriptional Regulation of Aerobic Metabolism in Pichia pastoris Fermentation.

    PubMed

    Zhang, Biao; Li, Baizhi; Chen, Dai; Zong, Jie; Sun, Fei; Qu, Huixin; Liang, Chongyang

    2016-01-01

    In this study, we investigated the classical fermentation process in Pichia pastoris based on transcriptomics. We utilized methanol in pichia yeast cell as the focus of our study, based on two key steps: limiting carbon source replacement (from glycerol to methonal) and fermentative production of exogenous proteins. In the former, the core differential genes in co-expression net point to initiation of aerobic metabolism and generation of peroxisome. The transmission electron microscope (TEM) results showed that yeast gradually adapted methanol induction to increased cell volume, and decreased density, via large number of peroxisomes. In the fermentative production of exogenous proteins, the Gene Ontology (GO) mapping results show that PAS_chr2-1_0582 played a vital role in regulating aerobic metabolic drift. In order to confirm the above results, we disrupted PAS_chr2-1_0582 by homologous recombination. Alcohol consumption was equivalent to one fifth of the normal control, and fewer peroxisomes were observed in Δ0582 strain following methanol induction. In this study we determined the important core genes and GO terms regulating aerobic metabolic drift in Pichia, as well as developing new perspectives for the continued development within this field. PMID:27537181

  6. Soil and sediment bacteria capable of aerobic nitrate respiration.

    PubMed Central

    Carter, J P; Hsaio, Y H; Spiro, S; Richardson, D J

    1995-01-01

    Several laboratory strains of gram-negative bacteria are known to be able to respire nitrate in the presence of oxygen, although the physiological advantage gained from this process is not entirely clear. The contribution that aerobic nitrate respiration makes to the environmental nitrogen cycle has not been studied. As a first step in addressing this question, a strategy which allows for the isolation of organisms capable of reducing nitrate to nitrite following aerobic growth has been developed. Twenty-nine such strains have been isolated from three soils and a freshwater sediment and shown to comprise members of three genera (Pseudomonas, Aeromonas, and Moraxella). All of these strains expressed a nitrate reductase with an active site located in the periplasmic compartment. Twenty-two of the strains showed significant rates of nitrate respiration in the presence of oxygen when assayed with physiological electron donors. Also isolated was one member of the gram-positive genus Arthrobacter, which was likewise able to respire nitrate in the presence of oxygen but appeared to express a different type of nitrate reductase. In the four environments studied, culturable bacteria capable of aerobic nitrate respiration were isolated in significant numbers (10(4) to 10(7) per g of soil or sediment) and in three cases were as abundant as, or more abundant than, culturable bacteria capable of denitrification. Thus, it seems likely that the corespiration of nitrate and oxygen may indeed make a significant contribution to the flux of nitrate to nitrite in the environment. PMID:7487017

  7. Aerobic and Anaerobic Respiration in Profiles of Polesie Lubelskie Peatlands

    NASA Astrophysics Data System (ADS)

    Szafranek-Nakonieczna, Anna; Stêpniewska, Zofia

    2014-04-01

    Soil respiration is a very important factor influencing carbon deposition in peat and reflecting the intensity of soil organic matter decomposition, root respiration, and the ease of transporting gases to the surface. Carbon dioxide release from three different peat soil profiles (0-80 cm) of the Polesie Lubelskie Region (Eastern Poland) was analyzed under laboratory conditions. Peat samples were incubated at 5, 10, and 20°C in aerobic and anaerobic environments, and their CO2-evolution was analyzed up to 14 days. The respiration activity was found to be in the range of 0.013-0.497 g CO2 kg-1 DW d-1. The respiratory quotient was estimated to be in the range of 0.51-1.51, and the difference in respiration rates over 10°C ranged between 4.15 and 8.72 in aerobic and from 1.15 to 6.53 in anaerobic conditions. A strong influence of temperature, depth, the degree of peat decomposition, pH, and nitrate content on respiration activity was found. Lack of oxygen at low temperature caused higher respiration activity than under aerobic conditions. These results should be taken into account when the management of Polish peatlands is considered in the context of climate and carbon storage, and physicochemical properties of soil in relation to soil respiration activity are considered.

  8. Adaptation of aerobically growing Pseudomonas aeruginosa to copper starvation.

    PubMed

    Frangipani, Emanuela; Slaveykova, Vera I; Reimmann, Cornelia; Haas, Dieter

    2008-10-01

    Restricted bioavailability of copper in certain environments can interfere with cellular respiration because copper is an essential cofactor of most terminal oxidases. The global response of the metabolically versatile bacterium and opportunistic pathogen Pseudomonas aeruginosa to copper limitation was assessed under aerobic conditions. Expression of cioAB (encoding an alternative, copper-independent, cyanide-resistant ubiquinol oxidase) was upregulated, whereas numerous iron uptake functions (including the siderophores pyoverdine and pyochelin) were expressed at reduced levels, presumably reflecting a lower demand for iron by respiratory enzymes. Wild-type P. aeruginosa was able to grow aerobically in a defined glucose medium depleted of copper, whereas a cioAB mutant did not grow. Thus, P. aeruginosa relies on the CioAB enzyme to cope with severe copper deprivation. A quadruple cyo cco1 cco2 cox mutant, which was deleted for all known heme-copper terminal oxidases of P. aeruginosa, grew aerobically, albeit more slowly than did the wild type, indicating that the CioAB enzyme is capable of energy conservation. However, the expression of a cioA'-'lacZ fusion was less dependent on the copper status in the quadruple mutant than in the wild type, suggesting that copper availability might affect cioAB expression indirectly, via the function of the heme-copper oxidases. PMID:18708503

  9. Comparison of selected aerobic and anaerobic procedures for MSW treatment.

    PubMed

    Fricke, Klaus; Santen, Heike; Wallmann, Rainer

    2005-01-01

    This paper considers selected efficiency rates and process data of aerobic and anaerobic procedures for the treatment of municipal solid waste and residual waste. Data are exclusively related to mechanical-biological treatment (MBT) procedures for generating waste appropriate for landfilling. The following aspects are regarded: general framework conditions for the application of MBT, efficiency of decomposition and of stabilisation, air and water emissions and energy balances. The presented data can be used for more efficient planning. In comparison to aerobic processes, anaerobic digestion can be ecologically advantageous, particularly with regard to exhaust emissions and energy balances. On the other hand, the wastewater emissions and the wastewater treatment required must be regarded as disadvantageous. Due to the relatively short period of operational history of most anaerobic processes for mechanical-biological waste treatment and thus limited experiences, operational reliability of anaerobic processes is slightly lower. Extensive biological stability of the treated waste for low-emission disposal cannot be reached by anaerobic digestion alone, but only in combination with additional aerobic post-treatment. In connection with the utilisation of renewable energies and the rising relevancy of climate protection, it can be affirmed that anaerobic digestion for the treatment of municipal solid waste has a high potential for further development. PMID:16125060

  10. Adherence of older women with strength training and aerobic exercise

    PubMed Central

    Picorelli, Alexandra Miranda Assumpção; Pereira, Daniele Sirineu; Felício, Diogo Carvalho; Dos Anjos, Daniela Maria; Pereira, Danielle Aparecida Gomes; Dias, Rosângela Corrêa; Assis, Marcella Guimarães; Pereira, Leani Souza Máximo

    2014-01-01

    Background Participation of older people in a program of regular exercise is an effective strategy to minimize the physical decline associated with age. The purpose of this study was to assess adherence rates in older women enrolled in two different exercise programs (one aerobic exercise and one strength training) and identify any associated clinical or functional factors. Methods This was an exploratory observational study in a sample of 231 elderly women of mean age 70.5 years. We used a structured questionnaire with standardized tests to evaluate the relevant clinical and functional measures. A specific adherence questionnaire was developed by the researchers to determine motivators and barriers to exercise adherence. Results The adherence rate was 49.70% in the aerobic exercise group and 56.20% in the strength training group. Multiple logistic regression models for motivation were significant (P=0.003) for the muscle strengthening group (R2=0.310) and also significant (P=0.008) for the aerobic exercise group (R2=0.154). A third regression model for barriers to exercise was significant (P=0.003) only for the muscle strengthening group (R2=0.236). The present study shows no direct relationship between worsening health status and poor adherence. Conclusion Factors related to adherence with exercise in the elderly are multifactorial. PMID:24600212

  11. Evaluation of an aerobic treatment for olive mill wastewater detoxification.

    PubMed

    El Hajjouji, Houda; El Fels, Loubna; Pinelli, Eric; Barje, Farid; El Asli, Abdelghani; Merlina, Georges; Hafidi, Mohamed

    2014-01-01

    Olive mill wastewater (OMWW) is a by-product of the olive oil extraction industry. Its dumping creates severe environmental problems in the Mediterranean countries. The phytoxicity of OMWW is due to the phenolic substances and is evaluated through a genotoxicity method. An aerobic treatment of OMWW was conducted during 45 days. Different concentrations of raw and treated OMWW were tested using the Vicia faba micronuclei test. Results showed that raw OMWW induced significant micronuclei formation at 10% of OMWW dilution. At 20% of dilution, no mitosis was recorded. The 45 days aerobic treatment OMWW showed an important decrease in the genotoxicity and also in the toxicity that was observed at 10% and 20% OMWW dilution. This could be correlated with the biodegradation of 76% of the total phenols. Indeed, qualitative analysis by high performance liquid chromatography shows the disappearance of the majority of phenolic compounds after 45 days of treatment. This study was completed by an agricultural test with V. faba plant. Data showed significant growth yield of 36.3% and 29.9% after being irrigated with 5 and 10 t/ha, respectively. These results supported the positive role of aerobic treatment on OMWW and their capacity to ameliorate the agronomic potential of these effluents. PMID:25244133

  12. Electric motor assisted bicycle as an aerobic exercise machine.

    PubMed

    Nagata, T; Okada, S; Makikawa, M

    2012-01-01

    The goal of this study is to maintain a continuous level of exercise intensity around the aerobic threshold (AT) during riding on an electric motor assisted bicycle using a new control system of electrical motor assistance which uses the efficient pedaling rate of popular bicycles. Five male subjects participated in the experiment, and the oxygen uptake was measured during cycling exercise using this new pedaling rate control system of electrical motor assistance, which could maintain the pedaling rate within a specific range, similar to that in previous type of electrically assisted bicycles. Results showed that this new pedaling rate control system at 65 rpm ensured continuous aerobic exercise intensity around the AT in two subjects, and this intensity level was higher than that observed in previous type. However, certain subjects were unable to maintain the expected exercise intensity because of their particular cycling preferences such as the pedaling rate. It is necessary to adjust the specific pedaling rate range of the electrical motor assist control according to the preferred pedaling rate, so that this system becomes applicable to anyone who want continuous aerobic exercise. PMID:23366293

  13. Microbial fuel cells with highly active aerobic biocathodes

    NASA Astrophysics Data System (ADS)

    Milner, Edward M.; Popescu, Dorin; Curtis, Tom; Head, Ian M.; Scott, Keith; Yu, Eileen H.

    2016-08-01

    Microbial fuel cells (MFCs), which convert organic waste to electricity, could be used to make the wastewater infrastructure more energy efficient and sustainable. However, platinum and other non-platinum chemical catalysts used for the oxygen reduction reaction (ORR) at the cathode of MFCs are unsustainable due to their high cost and long-term degradation. Aerobic biocathodes, which use microorganisms as the biocatalysts for cathode ORR, are a good alternative to chemical catalysts. In the current work, high-performing aerobic biocathodes with an onset potential for the ORR of +0.4 V vs. Ag/AgCl were enriched from activated sludge in electrochemical half-cells poised at -0.1 and + 0.2 V vs. Ag/AgCl. Gammaproteobacteria, distantly related to any known cultivated gammaproteobacterial lineage, were identified as dominant in these working electrode biofilms (23.3-44.3% of reads in 16S rRNA gene Ion Torrent libraries), and were in very low abundance in non-polarised control working electrode biofilms (0.5-0.7%). These Gammaproteobacteria were therefore most likely responsible for the high activity of biologically catalysed ORR. In MFC tests, a high-performing aerobic biocathode increased peak power 9-fold from 7 to 62 μW cm-2 in comparison to an unmodified carbon cathode, which was similar to peak power with a platinum-doped cathode at 70 μW cm-2.

  14. Concentric left ventricular morphology in aerobically trained kayak canoeists.

    PubMed

    Gates, Phillip E; Campbell, Ian G; George, Keith P

    2004-09-01

    The aim of the present study was to test the hypothesis that upper body aerobically trained athletes (kayak canoeists) would have greater left ventricular wall thickness, but similar left ventricular diastolic chamber dimensions, compared with recreationally active and sedentary men. Ultrasound echocardiography was used to determine cardiac structure and function in highly trained kayak canoeists (n = 10), moderately active (n = 10) and sedentary men (n = 10). The septal and posterior left ventricular walls were approximately 0.2 cm thicker in kayak canoeists (P < 0.05), and left ventricular mass was 51% and 32% greater (P < 0.05) in canoeists than in the sedentary and moderately trained participants, respectively. There were no differences in left ventricular chamber dimension, suggesting that the kayak canoeists had a concentric pattern of left ventricular adaptation to aerobic upper body training. Scaling the data to body composition indices had no effect on the outcome of the statistical analysis. There were no differences in resting Doppler left ventricular diastolic or systolic function among the groups. Ejection fraction was lower in the kayak canoeists, but the magnitude of the difference was within the normal variability for this measurement. Thus aerobically upper body trained athletes demonstrated a concentric pattern of cardiac enlargement, but resting left ventricle function was not different between athletes, moderately active and sedentary individuals. PMID:15513280

  15. Transcriptional Regulation of Aerobic Metabolism in Pichia pastoris Fermentation

    PubMed Central

    Zhang, Biao; Li, Baizhi; Chen, Dai; Zong, Jie; Sun, Fei; Qu, Huixin; Liang, Chongyang

    2016-01-01

    In this study, we investigated the classical fermentation process in Pichia pastoris based on transcriptomics. We utilized methanol in pichia yeast cell as the focus of our study, based on two key steps: limiting carbon source replacement (from glycerol to methonal) and fermentative production of exogenous proteins. In the former, the core differential genes in co-expression net point to initiation of aerobic metabolism and generation of peroxisome. The transmission electron microscope (TEM) results showed that yeast gradually adapted methanol induction to increased cell volume, and decreased density, via large number of peroxisomes. In the fermentative production of exogenous proteins, the Gene Ontology (GO) mapping results show that PAS_chr2-1_0582 played a vital role in regulating aerobic metabolic drift. In order to confirm the above results, we disrupted PAS_chr2-1_0582 by homologous recombination. Alcohol consumption was equivalent to one fifth of the normal control, and fewer peroxisomes were observed in Δ0582 strain following methanol induction. In this study we determined the important core genes and GO terms regulating aerobic metabolic drift in Pichia, as well as developing new perspectives for the continued development within this field. PMID:27537181

  16. Mixotrophy in the newly described phototrophic dinoflagellate Woloszynskia cincta from western Korean waters: feeding mechanism, prey species and effect of prey concentration.

    PubMed

    Kang, Nam Seon; Jeong, Hae Jin; Yoo, Yeong Du; Yoon, Eun Young; Lee, Kyung Ha; Lee, Kitack; Kim, Gwanghoon

    2011-01-01

    Woloszynskia species are dinoflagellates in the order Suessiales inhabiting marine or freshwater environments; their ecophysiology has not been well investigated, in particular, their trophic modes have yet to be elucidated. Previous studies have reported that all Woloszynskia species are photosynthetic, although their mixotrophic abilities have not been explored. We isolated a dinoflagellate from coastal waters in western Korea and established clonal cultures of this dinoflagellate. On the basis of morphology and analyses of the small/large subunit rRNA gene (GenBank accession number=FR690459), we identified this dinoflagellate as Woloszynskia cincta. We further established that this dinoflagellate is a mixotrophic species. We found that W. cincta fed on algal prey using a peduncle. Among the diverse prey provided, W. cincta ingested those algal species that had equivalent spherical diameters (ESDs) ≤12.6 μm, exceptions being the diatom Skeletonema costatum and the dinoflagellate Prorocentrum minimum. However, W. cincta did not feed on larger algal species that had ESDs≥15 μm. The specific growth rates for W. cincta increased continuously with increasing mean prey concentration before saturating at a concentration of ca. 134 ng C/ml (1,340 cells/ml) when Heterosigma akashiwo was used as food. The maximum specific growth rate (i.e. mixotrophic growth) of W. cincta feeding on H. akashiwo was 0.499 d(-1) at 20 °C under illumination of 20 μE/m(2) /s on a 14:10 h light-dark cycle, whereas its growth rate (i.e. phototrophic growth) under the same light conditions without added prey was 0.040 d(-1). The maximum ingestion and clearance rates of W. cincta feeding on H. akashiwo were 0.49 ng C/grazer/d (4.9 cells/grazer/d) and 1.9 μl/grazer/h, respectively. The calculated grazing coefficients for W. cincta on co-occurring H. akashiwo were up to 1.1 d(-1). The results of the present study suggest that grazing by W. cincta can have a potentially considerable impact

  17. Evaluation of the petrifilm aerobic count plate for enumeration of aerobic marine bacteria from seawater and Caulerpa lentillifera.

    PubMed

    Kudaka, Jun; Horii, Toru; Tamanaha, Koji; Itokazu, Kiyomasa; Nakamura, Masaji; Taira, Katsuya; Nidaira, Minoru; Okano, Sho; Kitahara, Akio

    2010-08-01

    The enumeration and evaluation of the activity of marine bacteria are important in the food industry. However, detection of marine bacteria in seawater or seafood has not been easy. The Petrifilm aerobic count plate (ACP) is a ready-to-use alternative to the traditional enumeration media used for bacteria associated with food. The purpose of this study was to evaluate the usefulness of a simple detection and enumeration method utilizing the Petrifilm ACP for enumeration of aerobic marine bacteria from seawater and an edible seaweed, Caulerpa lentillifera. The efficiency of enumeration of total aerobic marine bacteria on Petrifilm ACP was compared with that using the spread plate method on marine agar with 80 seawater and 64 C. lentillifera samples. With sterile seawater as the diluent, a close correlation was observed between the method utilizing Petrifilm ACP and that utilizing the conventional marine agar (r=0.98 for seawater and 0.91 for C. lentillifera). The Petrifilm ACP method was simpler and less time-consuming than the conventional method. These results indicate that Petrifilm ACP is a suitable alternative to conventional marine agar for enumeration of marine microorganisms in seawater and C. lentillifera samples. PMID:20819367

  18. The effect of intensity controlled aerobic dance exercise on aerobic capacity of middle-aged, overweight women.

    PubMed

    Gillett, P A; Eisenman, P A

    1987-12-01

    The purpose of this study was to determine the effect of intensity controlled exercise on the aerobic capacity of overweight, middle-aged women. Thirty-eight moderately overweight women, ages 35-57, participated in a 16-week dance-exercise program. Random assignment was made to an experimental group (n = 20) in which intensity of exercise was controlled and prescribed, and a control group (n = 18) in which exercise was of an intensity typical to commercial aerobic classes. Prior to the onset of training, and at the completion of 16 weeks, the following fitness tests were administered: Aerobic capacity expressed as VO2 max, body composition analysis, blood chemistry, blood pressure, resting heart rate, muscular endurance, and flexibility. T-tests, ANCOVA, and gain-score analyses were utilized to evaluate data. Both groups showed small changes in weight, percent fat, resting systolic and diastolic blood pressure, resting heart rate, high density lipoprotein-cholesterol (HDL-C), muscular endurance, and flexibility, but these changes were statistically nonsignificant. The VO2 max for the experimental group increased 41%, while the VO2 max for the control group increased 22% (p less than 0.05). The results suggest that the cardiovascular fitness changes for overweight, middle-aged women are greater when exercise intensity and progression are tailored to their age and fitness level. PMID:3423310

  19. Assessing aerobic natural attenuation of trichloroethene at four DOE sites

    SciTech Connect

    Koelsch, Michael C.; Starr, Robert C.; Sorenson, Jr., Kent S.

    2005-03-01

    A 3-year Department of Energy Environmental Science Management Program (EMSP) project is currently investigating natural attenuation of trichloroethane (TCE) in aerobic groundwater. This presentation summarizes the results of a screening process to identify TCE plumes at DOE facilities that are suitable for assessing the rate of TCE cometabolism under aerobic conditions. In order to estimate aerobic degradation rates, plumes had to meet the following criteria: TCE must be present in aerobic groundwater, a conservative co-contaminant must be present and have approximately the same source as TCE, and the groundwater velocity must be known. A total of 127 TCE plumes were considered across 24 DOE sites. The four sites retained for the assessment were: (1) Brookhaven National Laboratory, OU III; (2) Paducah Gaseous Diffusion Plant, Northwest Plume; (3) Rocky Flats Environmental Technology Site, Industrialized Area--Southwest Plume and 903 Pad South Plume; and (4) Savannah River Site, A/M Area Plume. For each of these sites, a co-contaminant derived from the same source area as TCE was used as a nonbiodegrading tracer. The tracer determined the extent to which concentration decreases in the plume can be accounted for solely by abiotic processes such as dispersion and dilution. Any concentration decreases not accounted for by these processes must be explained by some other natural attenuation mechanism. Thus, ''half-lives'' presented herein are in addition to attenuation that occurs due to hydrologic mechanisms. This ''tracer-corrected method'' has previously been used at the DOE's Idaho National Engineering and Environmental Laboratory in conjunction with other techniques to document the occurrence of intrinsic aerobic cometabolism. Application of this method to other DOE sites is the first step to determining whether this might be a significant natural attenuation mechanism on a broader scale. Application of the tracer-corrected method to data from the Brookhaven

  20. ASSESSING AEROBIC NATURAL ATTENUATION OF TRICHLOROETHENE AT FOUR DOE SITES

    SciTech Connect

    Michael C. Koelsch; Robert C. Starr; Kent S. Sorenson, Jr.

    2005-03-01

    A 3-year Department of Energy Environmental Science Management Program (EMSP) project is currently investigating natural attenuation of trichloroethane (TCE) in aerobic groundwater. This presentation summarizes the results of a screening process to identify TCE plumes at DOE facilities that are suitable for assessing the rate of TCE cometabolism under aerobic conditions. In order to estimate aerobic degradation rates, plumes had to meet the following criteria: TCE must be present in aerobic groundwater, a conservative co-contaminant must be present and have approximately the same source as TCE, and the groundwater velocity must be known. A total of 127 TCE plumes were considered across 24 DOE sites. The four sites retained for the assessment were: (1) Brookhaven National Laboratory, OU III; (2) Paducah Gaseous Diffusion Plant, Northwest Plume; (3) Rocky Flats Environmental Technology Site, Industrialized Area--Southwest Plume and 903 Pad South Plume; and (4) Savannah River Site, A/M Area Plume. For each of these sites, a co-contaminant derived from the same source area as TCE was used as a nonbiodegrading tracer. The tracer determined the extent to which concentration decreases in the plume can be accounted for solely by abiotic processes such as dispersion and dilution. Any concentration decreases not accounted for by these processes must be explained by some other natural attenuation mechanism. Thus, ''half-lives'' presented herein are in addition to attenuation that occurs due to hydrologic mechanisms. This ''tracer-corrected method'' has previously been used at the DOE's Idaho National Engineering and Environmental Laboratory in conjunction with other techniques to document the occurrence of intrinsic aerobic cometabolism. Application of this method to other DOE sites is the first step to determining whether this might be a significant natural attenuation mechanism on a broader scale. Application of the tracer-corrected method to data from the Brookhaven

  1. Aerobic fitness is associated with greater hippocampal cerebral blood flow in children.

    PubMed

    Chaddock-Heyman, Laura; Erickson, Kirk I; Chappell, Michael A; Johnson, Curtis L; Kienzler, Caitlin; Knecht, Anya; Drollette, Eric S; Raine, Lauren B; Scudder, Mark R; Kao, Shih-Chun; Hillman, Charles H; Kramer, Arthur F

    2016-08-01

    The present study is the first to investigate whether cerebral blood flow in the hippocampus relates to aerobic fitness in children. In particular, we used arterial spin labeling (ASL) perfusion MRI to provide a quantitative measure of blood flow in the hippocampus in 73 7- to 9-year-old preadolescent children. Indeed, aerobic fitness was found to relate to greater perfusion in the hippocampus, independent of age, sex, and hippocampal volume. Such results suggest improved microcirculation and cerebral vasculature in preadolescent children with higher levels of aerobic fitness. Further, aerobic fitness may influence how the brain regulates its metabolic demands via blood flow in a region of the brain important for learning and memory. To add specificity to the relationship of fitness to the hippocampus, we demonstrate no significant association between aerobic fitness and cerebral blood flow in the brainstem. Our results reinforce the importance of aerobic fitness during a critical period of child development. PMID:27419884

  2. How to Make Students Feel Happy in the Course of Aerobics

    NASA Astrophysics Data System (ADS)

    Wang, Yuezhi

    With its own charm, aerobics is accepted by more and more university students, and becomes one of the most popular sports for girls in colleges. So the Aerobics Teachers must change the single mode of teaching. Aerobics Teachers should start from the actual situations, adopt the method of "group teach", and teach students to appreciate themselves and help each other in a team. And teachers also should make students feel happy of success and sports when they compete in teams.

  3. Beyond vascularization: aerobic fitness is associated with N-acetylaspartate and working memory.

    PubMed

    Erickson, Kirk I; Weinstein, Andrea M; Sutton, Bradley P; Prakash, Ruchika Shaurya; Voss, Michelle W; Chaddock, Laura; Szabo, Amanda N; Mailey, Emily L; White, Siobhan M; Wojcicki, Thomas R; McAuley, Edward; Kramer, Arthur F

    2012-01-01

    Aerobic exercise is a promising form of prevention for cognitive decline; however, little is known about the molecular mechanisms by which exercise and fitness impacts the human brain. Several studies have postulated that increased regional brain volume and function are associated with aerobic fitness because of increased vascularization rather than increased neural tissue per se. We tested this position by examining the relationship between cardiorespiratory fitness and N-acetylaspartate (NAA) levels in the right frontal cortex using magnetic resonance spectroscopy. NAA is a nervous system specific metabolite found predominantly in cell bodies of neurons. We reasoned that if aerobic fitness was predominantly influencing the vasculature of the brain, then NAA levels should not vary as a function of aerobic fitness. However, if aerobic fitness influences the number or viability of neurons, then higher aerobic fitness levels might be associated with greater concentrations of NAA. We examined NAA levels, aerobic fitness, and cognitive performance in 137 older adults without cognitive impairment. Consistent with the latter hypothesis, we found that higher aerobic fitness levels offset an age-related decline in NAA. Furthermore, NAA mediated an association between fitness and backward digit span performance, suggesting that neuronal viability as measured by NAA is important in understanding fitness-related cognitive enhancement. Since NAA is found exclusively in neural tissue, our results indicate that the effect of fitness on the human brain extends beyond vascularization; aerobic fitness is associated with neuronal viability in the frontal cortex of older adults. PMID:22574272

  4. Removal of Pesticides and Inorganic Contaminants in Anaerobic and Aerobic Biological Contactors

    EPA Science Inventory

    This presentation contains data on the removal of pesticides (acetochlor, clethodim, dicrotophos), ammonia, nitrate, bromate and perchlorate through aerobic and anaerobic biological treatment processes.

  5. What are the differences between aerobic and anaerobic toxic effects of sulfonamides on Escherichia coli?

    PubMed

    Qin, Mengnan; Lin, Zhifen; Wang, Dali; Long, Xi; Zheng, Min; Qiu, Yanling

    2016-01-01

    Bacteria in the environment face the threat of antibiotics. However, most studies investigating the toxicity and toxicity mechanisms of antibiotics have been conducted on microorganisms in aerobic conditions, while studies examining the anaerobic toxicity and toxicity mechanisms of antibiotics are still limited. In this study, we determined the aerobic and anaerobic toxicities of sulfonamides (SAs) on Escherichia coli. Next, a comparison of the aerobic and anaerobic toxicities indicated that the SAs could be divided into three groups: Group I: log(1/EC50-anaerobic)>log(1/EC50-aerobic) (EC50-anaerobic/EC50-aerobic, the median effective concentration under anaerobic/aerobic conditions), Group II: log(1/EC50-anaerobic)≈log(1/EC50-aerobic), and Group III: log(1/EC50-anaerobic)aerobic). Furthermore, this division was not based on the reactive oxygen species (ROS) level or the interaction energy (Ebinding) value, which represents the affinity between SAs and dihydropteroate synthase (dhps) but rather on the total binding energy. Furthermore, SAs with greatly similar structures were categorized into different groups. This deep insight into the difference between aerobic and anaerobic toxicities will benefit environmental science, and the results of this study will serve as a reference for the risk assessment of chemicals in the environment. PMID:26748048

  6. Stable carbon isotope fractionation during aerobic biodegradation of chlorinated ethenes

    SciTech Connect

    Chu, Kung-Hui; Mahendra, Shaily; Song, Donald L.; Conrad, Mark E.; Alvarez-Cohen, Lisa

    2003-06-01

    Stable isotope analysis is recognized as a powerful tool for monitoring, assessing, and validating in-situ bioremediation processes. In this study, kinetic carbon isotope fractionation factors () associated with the aerobic biodegradation of vinyl chloride (VC), cis-1,2-dichloroethylene (cDCE), and trichloroethylene (TCE) were examined. Of the three solvents, the largest fractionation effects were observed for biodegradation of VC. Both metabolic and cometabolic VC degradation were studied using Mycobacterium aurum L1 (grown on VC), Methylosinus trichosporium OB3b (grown on methane), Mycobacterium vaccae JOB 5 (grown on propane), and two VC enrichment cultures seeded from contaminated soils of Alameda Point and Travis Air Force Base, CA. M. aurum L1 caused the greatest fractionation (= -5.7) while for the cometabolic cultures, values ranged from -3.2 to -4.8. VC fractionation patterns for the enrichment cultures were within the range of those observed for the metabolic and cometabolic cultures (= -4.5 to -5.5). The fractionation for cometabolic degradation of TCE by Me. trichosporium OB3b was low (= -1.1), while no quantifiable carbon isotopic fractionation was observed during the cometabolic degradation of cDCE. For all three of the tested chlorinated ethenes, isotopic fractionation measured during aerobic degradation was significantly smaller than that reported for anaerobic reductive dechlorination. This study suggests that analysis of compound-specific isotopic fractionation could assist in determining whether aerobic or anaerobic degradation of VC and cDCE predominates in field applications of in-situ bioremediation. In contrast, isotopic fractionation effects associated with metabolic and cometabolic reactions are not sufficiently dissimilar to distinguish these processes in the field.

  7. Specificity of aerobic and anaerobic work capacities and powers.

    PubMed

    Boulay, M R; Lortie, G; Simoneau, J A; Hamel, P; Leblanc, C; Bouchard, C

    1985-12-01

    Thirty-three untrained subjects of both sexes, 18-31 years of age, performed several tests on cycle ergometers. Maximal aerobic power (MAP) was obtained in a progressive work test. Maximal aerobic capacity (MAC) was measured in a 90-min maximal test and was computed as the total work output during that period. Two all-out cycle ergometer work tests lasting 10 s and 90 s were used to estimate the anaerobic alactic capacity (AAC) and lactic capacity (ALC). Anaerobic alactic power (AAP) was computed as the highest output in 1 s in the AAC test and anaerobic lactic power (ALP) was obtained as the mean output during the last 5 s in an all-out test of 30 s. Correlation coefficients were computed between all measurements of capacity and power expressed per kg of body weight as well as with scores adjusted for sex differences. Common variances (r2 X 100) between measurements of power were either low (MAP-AAP, 40%) or moderate (MAP-ALP, 61%; AAP-ALP, 62%) while common variances between measurements of capacity were sometimes low (MAC-AAC, 49%) or higher (MAC-ALC, 76%; AAC-ALC, 77%). The common variances between tests of power and capacity reached high values when calculated with metabolic criteria of the same class (MAP-MAC, 81%; AAP-AAC, 92%). These results provide quantitative evidence to support the notion of specificity between the aerobic and the anaerobic work performances and support the distinction between capacity and power of the three energy systems. PMID:4077360

  8. Aerobic Granules: Microbial Landscape and Architecture, Stages, and Practical Implications

    PubMed Central

    Holliger, Christof

    2014-01-01

    For the successful application of aerobic granules in wastewater treatment, granules containing an appropriate microbial assembly able to remove contaminants should be retained and propagated within the reactor. To manipulate and/or optimize this process, a good understanding of the formation and dynamic architecture of the granules is desirable. Models of granules often assume a spherical shape with an outer layer and an inner core, but limited information is available regarding the extent of deviations from such assumptions. We report on new imaging approaches to gain detailed insights into the structural characteristics of aerobic granules. Our approach stained all components of the granule to obtain a high quality contrast in the images; hence limitations due to thresholding in the image analysis were overcome. A three-dimensional reconstruction of the granular structure was obtained that revealed the mesoscopic impression of the cavernlike interior of the structure, showing channels and dead-end paths in detail. In “old” granules, large cavities allowed for the irrigation and growth of dense microbial colonies along the path of the channels. Hence, in some areas, paradoxically higher biomass content was observed in the inner part of the granule compared to the outer part. Microbial clusters “rooting” from the interior of the mature granule structure indicate that granules mainly grow via biomass outgrowth and not by aggregation of small particles. We identify and discuss phenomena contributing to the life cycle of aerobic granules. With our approach, volumetric tetrahedral grids are generated that may be used to validate complex models of granule formation. PMID:24657859

  9. Effects of Aerobic Exercise on Anxiety Disorders: A Systematic Review.

    PubMed

    de Souza Moura, Antonio Marcos; Lamego, Murilo Khede; Paes, Flávia; Ferreira Rocha, Nuno Barbosa; Simoes-Silva, Vitor; Rocha, Susana Almeida; de Sá Filho, Alberto Souza; Rimes, Ridson; Manochio, João; Budde, Henning; Wegner, Mirko; Mura, Gioia; Arias-Carrión, Oscar; Yuan, Ti-Fei; Nardi, Antonio Egidio; Machado, Sergio

    2015-01-01

    Anxiety disorders are the most common psychiatric disorders observed currently. It is a normal adaptive response to stress that allows coping with adverse situations. Nevertheless, when anxiety becomes excessive or disproportional in relation to the situation that evokes it or when there is not any special object directed at it, such as an irrational dread of routine stimuli, it becomes a disabling disorder and is considered to be pathological. The traditional treatment used is medication and cognitive behavioral psychotherapy, however, last years the practice of physical exercise, specifically aerobic exercise, has been investigated as a new non-pharmacological therapy for anxiety disorders. Thus, the aim of this article was to provide information on research results and key chains related to the therapeutic effects of aerobic exercise compared with other types of interventions to treat anxiety, which may become a useful clinical application in a near future. Researches have shown the effectiveness of alternative treatments, such as physical exercise, minimizing high financial costs and minimizing side effects. The sample analyzed, 66.8% was composed of women and 80% with severity of symptoms anxiety as moderate to severe. The data analyzed in this review allows us to claim that alternative therapies like exercise are effective in controlling and reducing symptoms, as 91% of anxiety disorders surveys have shown effective results in treating. However, there is still disagreement regarding the effect of exercise compared to the use of antidepressant symptoms and cognitive function in anxiety, this suggests that there is no consensus on the correct intensity of aerobic exercise as to achieve the best dose-response, with intensities high to moderate or moderate to mild. PMID:26556089

  10. Cognitive enhancement by transcranial laser stimulation and acute aerobic exercise.

    PubMed

    Hwang, Jungyun; Castelli, Darla M; Gonzalez-Lima, F

    2016-08-01

    This is the first randomized, controlled study comparing the cognitive effects of transcranial laser stimulation and acute aerobic exercise on the same cognitive tasks. We examined whether transcranial infrared laser stimulation of the prefrontal cortex, acute high-intensity aerobic exercise, or the combination may enhance performance in sustained attention and working memory tasks. Sixty healthy young adults were randomly assigned to one of the following four treatments: (1) low-level laser therapy (LLLT) with infrared laser to two forehead sites while seated (total 8 min, 1064 nm continuous wave, 250 mW/cm(2), 60 J/cm(2) per site of 13.6 cm(2)); (2) acute exercise (EX) of high-intensity (total 20 min, with 10-min treadmill running at 85-90 % VO2max); (3) combined treatment (LLLT + EX); or (4) sham control (CON). Participants were tested for prefrontal measures of sustained attention with the psychomotor vigilance task (PVT) and working memory with the delayed match-to-sample task (DMS) before and after the treatments. As compared to CON, both LLLT and EX reduced reaction time in the PVT [F(1.56) = 4.134, p = 0.01, η (2)  = 0.181] and increased the number of correct responses in the DMS [F(1.56) = 4.690, p = 0.005, η (2)  = 0.201], demonstrating a significant enhancing effect of LLLT and EX on cognitive performance. LLLT + EX effects were similar but showed no significantly greater improvement on PVT and DMS than LLLT or EX alone. The transcranial infrared laser stimulation and acute aerobic exercise treatments were similarly effective for cognitive enhancement, suggesting that they augment prefrontal cognitive functions similarly. PMID:27220529

  11. Aerobic granules: microbial landscape and architecture, stages, and practical implications.

    PubMed

    Gonzalez-Gil, Graciela; Holliger, Christof

    2014-06-01

    For the successful application of aerobic granules in wastewater treatment, granules containing an appropriate microbial assembly able to remove contaminants should be retained and propagated within the reactor. To manipulate and/or optimize this process, a good understanding of the formation and dynamic architecture of the granules is desirable. Models of granules often assume a spherical shape with an outer layer and an inner core, but limited information is available regarding the extent of deviations from such assumptions. We report on new imaging approaches to gain detailed insights into the structural characteristics of aerobic granules. Our approach stained all components of the granule to obtain a high quality contrast in the images; hence limitations due to thresholding in the image analysis were overcome. A three-dimensional reconstruction of the granular structure was obtained that revealed the mesoscopic impression of the cavernlike interior of the structure, showing channels and dead-end paths in detail. In "old" granules, large cavities allowed for the irrigation and growth of dense microbial colonies along the path of the channels. Hence, in some areas, paradoxically higher biomass content was observed in the inner part of the granule compared to the outer part. Microbial clusters "rooting" from the interior of the mature granule structure indicate that granules mainly grow via biomass outgrowth and not by aggregation of small particles. We identify and discuss phenomena contributing to the life cycle of aerobic granules. With our approach, volumetric tetrahedral grids are generated that may be used to validate complex models of granule formation. PMID:24657859

  12. Criterion Related Validity of Karate Specific Aerobic Test (KSAT)

    PubMed Central

    Chaabene, Helmi; Hachana, Younes; Franchini, Emerson; Tabben, Montassar; Mkaouer, Bessem; Negra, Yassine; Hammami, Mehrez; Chamari, Karim

    2015-01-01

    Background: Karate is one the most popular combat sports in the world. Physical fitness assessment on a regular manner is important for monitoring the effectiveness of the training program and the readiness of karatekas to compete. Objectives: The aim of this research was to examine the criterion related to validity of the karate specific aerobic test (KSAT) as an indicator of aerobic level of karate practitioners. Patients and Methods: Cardiorespiratory responses, aerobic performance level through both treadmill laboratory test and YoYo intermittent recovery test level 1 (YoYoIRTL1) as well as time to exhaustion in the KSAT test (TE’KSAT) were determined in a total of fifteen healthy international karatekas (i.e. karate practitioners) (means ± SD: age: 22.2 ± 4.3 years; height: 176.4 ± 7.5 cm; body mass: 70.3 ± 9.7 kg and body fat: 13.2 ± 6%). Results: Peak heart rate obtained from KSAT represented ~99% of maximal heart rate registered during the treadmill test showing that KSAT imposes high physiological demands. There was no significant correlation between KSAT’s TE and relative (mL/min kg) treadmill maximal oxygen uptake (r = 0.14; P = 0.69; [small]). On the other hand, there was a significant relationship between KSAT’s TE and the velocity associated with VO2max (vVO2max) (r = 0.67; P = 0.03; [large]) as well as the velocity at VO2 corresponding to the second ventilatory threshold (vVO2 VAT) (r = 0.64; P = 0.04; [large]). Moreover, significant relationship was found between TE’s KSAT and both the total distance covered and parameters of intermittent endurance measured through YoYoIRTL1. Conclusions: The KSAT has not proved to have indirect criterion related validity as no significant correlations have been found between TE’s KSAT and treadmill VO2max. Nevertheless, as correlated to other aerobic fitness variables, KSAT can be considered as an indicator of karate specific endurance. The establishment of the criterion related validity of the KSAT

  13. New records in aerobic power among octogenarian lifelong endurance athletes

    PubMed Central

    Hayes, Erik; Galpin, Andrew; Kaminsky, Leonard; Jemiolo, Bozena; Fink, William; Trappe, Todd; Jansson, Anna; Gustafsson, Thomas; Tesch, Per

    2013-01-01

    We examined whole body aerobic capacity and myocellular markers of oxidative metabolism in lifelong endurance athletes [n = 9, 81 ± 1 yr, 68 ± 3 kg, body mass index (BMI) = 23 ± 1 kg/m2] and age-matched, healthy, untrained men (n = 6; 82 ± 1 y, 77 ± 5 kg, BMI = 26 ± 1 kg/m2). The endurance athletes were cross-country skiers, including a former Olympic champion and several national/regional champions, with a history of aerobic exercise and participation in endurance events throughout their lives. Each subject performed a maximal cycle test to assess aerobic capacity (V̇o2max). Subjects had a resting vastus lateralis muscle biopsy to assess oxidative enzymes (citrate synthase and βHAD) and molecular (mRNA) targets associated with mitochondrial biogenesis [peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α) and mitochondrial transcription factor A (Tfam)]. The octogenarian athletes had a higher (P < 0.05) absolute (2.6 ± 0.1 vs. 1.6 ± 0.1 l/min) and relative (38 ± 1 vs. 21 ± 1 ml·kg−1·min−1) V̇o2max, ventilation (79 ± 3 vs. 64 ± 7 l/min), heart rate (160 ± 5 vs. 146 ± 8 beats per minute), and final workload (182 ± 4 vs. 131 ± 14 W). Skeletal muscle oxidative enzymes were 54% (citrate synthase) and 42% (βHAD) higher (P < 0.05) in the octogenarian athletes. Likewise, basal PGC-1α and Tfam mRNA were 135% and 80% greater (P < 0.05) in the octogenarian athletes. To our knowledge, the V̇o2max of the lifelong endurance athletes is the highest recorded in humans >80 yr of age and comparable to nonendurance trained men 40 years younger. The superior cardiovascular and skeletal muscle health profile of the octogenarian athletes provides a large functional reserve above the aerobic frailty threshold and is associated with lower risk for disability and mortality. PMID:23065759

  14. Biodegradation of Asphalt Cement-20 by Aerobic Bacteria

    PubMed Central

    Pendrys, John P.

    1989-01-01

    Seven gram-negative, aerobic bacteria were isolated from a mixed culture enriched for asphalt-degrading bacteria. The predominant genera of these isolates were Pseudomonas, Acinetobacter, Alcaligenes, Flavimonas, and Flavobacterium. The mixed culture preferentially degraded the saturate and naphthene aromatic fractions of asphalt cement-20. A residue remained on the surface which was resistant to biodegradation and protected the underlying asphalt from biodegradation. The most potent asphalt-degrading bacterium, Acinetobacter calcoaceticus NAV2, excretes an emulsifier which is capable of emulsifying the saturate and naphthene aromatic fractions of asphalt cement-20. This emulsifier is not denatured by phenol. PMID:16347928

  15. Aerobic Microbial Respiration in Oceanic Oxygen Minimum Zones

    NASA Astrophysics Data System (ADS)

    Kalvelage, Tim; Lavik, Gaute; Jensen, Marlene M.; Revsbech, Niels Peter; Schunck, Harald; Loescher, Carolin; Desai, Dhwani K.; LaRoche, Julie; Schmitz-Streit, Ruth; Kuypers, Marcel M. M.

    2014-05-01

    In the oxygen minimum zones (OMZs) of the tropical oceans, sluggish ventilation combined with strong microbial respiration of sinking organic matter results in the depletion of oxygen (O2). When O2 concentrations drop below ~5 µmol/L, organic matter is generally assumed to be respired with nitrate, ultimately leading to the loss of fixed inorganic nitrogen via anammox and denitrification. However, direct measurements of microbial O2 consumption at low O2 levels are - apart from a single experiment conducted in the OMZ off Peru - so far lacking. At the same time, consistently observed active aerobic ammonium and nitrite oxidation at non-detectable O2 concentrations (<1 µmol/L) in all major OMZs, suggests aerobic microorganisms, likely including heterotrophs, to be well adapted to near-anoxic conditions. Consequently, microaerobic (≤5 µmol/L) remineralization of organic matter, and thus release of ammonium, in low- O2 environments might be significantly underestimated at present. Here we present extensive measurements of microbial O2 consumption in OMZ waters, combined with highly sensitive O2 (STOX) measurements and meta-omic functional gene analyses. Short-term incubation experiments with labelled O2 (18-18O2) carried out in the Namibian and Peruvian OMZ, revealed persistent aerobic microbial activity at depths with non-detectable concentrations of O2 (≤50 nmol/L). In accordance, examination of metagenomes and metatranscriptomes from Chilean and Peruvian OMZ waters identified genes encoding for terminal respiratory oxidases with high O2 affinities as well as their expression by diverse microbial communities. Oxygen consumption was particularly enhanced near the upper OMZ boundaries and could mostly (~80%) be assigned to heterotrophic microbial activity. Compared to previously identified anaerobic microbial processes, microaerobic organic matter respiration was the dominant remineralization pathway and source of ammonium (~90%) in the upper Namibian and

  16. Endurance training and aerobic fitness in young people.

    PubMed

    Baquet, Georges; van Praagh, Emmanuel; Berthoin, Serge

    2003-01-01

    Training-induced adaptations in aerobic fitness have been extensively studied in adults, and some exercise scientists have recommended similar training programmes for young people. However, the subject of the response to aerobic training of children and adolescents is controversial. The effects of exercise training on prepubertal children are particularly debatable. The latter may be partly explained by different training designs, which make comparisons between studies very problematic. We have analysed the procedures applied to protocol design and training methods to highlight the real impact of aerobic training on the peak oxygen uptake (V-dotO2) of healthy children and adolescents. In accordance with previously published reviews on trainability in youngsters, research papers were rejected from the final analysis according to criteria such as the lack of a control group, an unclear training protocol, inappropriate statistical procedures, small sample size, studies with trained or special populations, or with no peak V-dotO2 data. Factors such as maturity, group constitution, consistency between training and testing procedures, drop out rates, or attendance were considered, and possible associations with changes in peak V-dotO2 with training are discussed. From 51 studies reviewed, 22 were finally retained. In most of the studies, there was a considerable lack of research regarding circumpubertal individuals in general, and particularly in girls. The results suggest that methodologically listed parameters will exert a potential influence on the magnitude of peak V-dotO2 improvement. Even if little difference is reported for each parameter, it is suggested that the sum of errors will result in a significant bias in the assessment of training effects. The characteristics of each training protocol were also analysed to establish their respective potential influence on peak V-dotO2 changes. In general, aerobic training leads to a mean improvement of 5-6% in the peak V

  17. Development of a specific anaerobic field test for aerobic gymnastics.

    PubMed

    Alves, Christiano Robles Rodrigues; Borelli, Marcello Tadeu Caetano; Paineli, Vitor de Salles; Azevedo, Rafael de Almeida; Borelli, Claudia Cristine Gomes; Lancha Junior, Antônio Herbert; Gualano, Bruno; Artioli, Guilherme Giannini

    2015-01-01

    The current investigation aimed to develop a valid specific field test to evaluate anaerobic physical performance in Aerobic Gymnastics athletes. We first designed the Specific Aerobic Gymnast Anaerobic Test (SAGAT), which included gymnastics-specific elements performed in maximal repeated sprint fashion, with a total duration of 80-90 s. In order to validate the SAGAT, three independent sub-studies were performed to evaluate the concurrent validity (Study I, n=8), the reliability (Study II, n=10) and the sensitivity (Study III, n=30) of the test in elite female athletes. In Study I, a positive correlation was shown between lower-body Wingate test and SAGAT performance (Mean power: p = 0.03, r = -0.69, CI: -0.94 to 0.03 and Peak power: p = 0.02, r = -0.72, CI: -0.95 to -0.04) and between upper-body Wingate test and SAGAT performance (Mean power: p = 0.03, r = -0.67, CI: -0.94 to 0.02 and Peak power: p = 0.03, r = -0.69, CI: -0.94 to 0.03). Additionally, plasma lactate was similarly increased in response to SAGAT (p = 0.002), lower-body Wingate Test (p = 0.021) and a simulated competition (p = 0.007). In Study II, no differences were found between the time to complete the SAGAT in repeated trials (p = 0.84; Cohen's d effect size = 0.09; ICC = 0.97, CI: 0.89 to 0.99; MDC95 = 0.12 s). Finally, in Study III the time to complete the SAGAT was significantly lower during the competition cycle when compared to the period before the preparatory cycle (p < 0.001), showing an improvement in SAGAT performance after a specific Aerobic Gymnastics training period. Taken together, these data have demonstrated that SAGAT is a specific, reliable and sensitive measurement of specific anaerobic performance in elite female Aerobic Gymnastics, presenting great potential to be largely applied in training settings. PMID:25876039

  18. Development of a Specific Anaerobic Field Test for Aerobic Gymnastics

    PubMed Central

    Paineli, Vitor de Salles; Azevedo, Rafael de Almeida; Borelli, Claudia Cristine Gomes; Lancha Junior, Antônio Herbert; Gualano, Bruno; Artioli, Guilherme Giannini

    2015-01-01

    The current investigation aimed to develop a valid specific field test to evaluate anaerobic physical performance in Aerobic Gymnastics athletes. We first designed the Specific Aerobic Gymnast Anaerobic Test (SAGAT), which included gymnastics-specific elements performed in maximal repeated sprint fashion, with a total duration of 80-90 s. In order to validate the SAGAT, three independent sub-studies were performed to evaluate the concurrent validity (Study I, n=8), the reliability (Study II, n=10) and the sensitivity (Study III, n=30) of the test in elite female athletes. In Study I, a positive correlation was shown between lower-body Wingate test and SAGAT performance (Mean power: p = 0.03, r = -0.69, CI: -0.94 to 0.03 and Peak power: p = 0.02, r = -0.72, CI: -0.95 to -0.04) and between upper-body Wingate test and SAGAT performance (Mean power: p = 0.03, r = -0.67, CI: -0.94 to 0.02 and Peak power: p = 0.03, r = -0.69, CI: -0.94 to 0.03). Additionally, plasma lactate was similarly increased in response to SAGAT (p = 0.002), lower-body Wingate Test (p = 0.021) and a simulated competition (p = 0.007). In Study II, no differences were found between the time to complete the SAGAT in repeated trials (p = 0.84; Cohen’s d effect size = 0.09; ICC = 0.97, CI: 0.89 to 0.99; MDC95 = 0.12 s). Finally, in Study III the time to complete the SAGAT was significantly lower during the competition cycle when compared to the period before the preparatory cycle (p < 0.001), showing an improvement in SAGAT performance after a specific Aerobic Gymnastics training period. Taken together, these data have demonstrated that SAGAT is a specific, reliable and sensitive measurement of specific anaerobic performance in elite female Aerobic Gymnastics, presenting great potential to be largely applied in training settings. PMID:25876039

  19. Aerobic exercise training reduces arterial stiffness in metabolic syndrome

    PubMed Central

    Donley, David A.; Fournier, Sara B.; Reger, Brian L.; DeVallance, Evan; Bonner, Daniel E.; Olfert, I. Mark; Frisbee, Jefferson C.

    2014-01-01

    The metabolic syndrome (MetS) is associated with a threefold increase risk of cardiovascular disease (CVD) mortality partly due to increased arterial stiffening. We compared the effects of aerobic exercise training on arterial stiffening/mechanics in MetS subjects without overt CVD or type 2 diabetes. MetS and healthy control (Con) subjects underwent 8 wk of exercise training (ExT; 11 MetS and 11 Con) or remained inactive (11 MetS and 10 Con). The following measures were performed pre- and postintervention: radial pulse wave analysis (applanation tonometry) was used to measure augmentation pressure and index, central pressures, and an estimate of myocardial efficiency; arterial stiffness was assessed from carotid-femoral pulse-wave velocity (cfPWV, applanation tonometry); carotid thickness was assessed from B-mode ultrasound; and peak aerobic capacity (gas exchange) was performed in the seated position. Plasma matrix metalloproteinases (MMP) and CVD risk (Framingham risk score) were also assessed. cfPWV was reduced (P < 0.05) in MetS-ExT subjects (7.9 ± 0.6 to 7.2 ± 0.4 m/s) and Con-ExT (6.6 ± 1.8 to 5.6 ± 1.6 m/s). Exercise training reduced (P < 0.05) central systolic pressure (116 ± 5 to 110 ± 4 mmHg), augmentation pressure (9 ± 1 to 7 ± 1 mmHg), augmentation index (19 ± 3 to 15 ± 4%), and improved myocardial efficiency (155 ± 8 to 168 ± 9), but only in the MetS group. Aerobic capacity increased (P < 0.05) in MetS-ExT (16.6 ± 1.0 to 19.9 ± 1.0) and Con-ExT subjects (23.8 ± 1.6 to 26.3 ± 1.6). MMP-1 and -7 were correlated with cfPWV, and both MMP-1 and -7 were reduced post-ExT in MetS subjects. These findings suggest that some of the pathophysiological changes associated with MetS can be improved after aerobic exercise training, thereby lowering their cardiovascular risk. PMID:24744384

  20. A dual-species co-cultivation system to study the interactions between Roseobacters and dinoflagellates

    PubMed Central

    Wang, Hui; Tomasch, Jürgen; Jarek, Michael; Wagner-Döbler, Irene

    2014-01-01

    Some microalgae in nature live in symbiosis with microorganisms that can enhance or inhibit growth, thus influencing the dynamics of phytoplankton blooms. In spite of the great ecological importance of these interactions, very few defined laboratory systems are available to study them in detail. Here we present a co-cultivation system consisting of the toxic phototrophic dinoflagellate Prorocentrum minimum and the photoheterotrophic alphaproteobacterium Dinoroseobacter shibae. In a mineral medium lacking a carbon source, vitamins for the bacterium and the essential vitamin B12 for the dinoflagellate, growth dynamics reproducibly went from a mutualistic phase, where both algae and bacteria grow, to a pathogenic phase, where the algae are killed by the bacteria. The data show a “Jekyll and Hyde” lifestyle that had been proposed but not previously demonstrated. We used RNAseq and microarray analysis to determine which genes of D. shibae are transcribed and differentially expressed in a light dependent way at an early time-point of the co-culture when the bacterium grows very slowly. Enrichment of bacterial mRNA for transcriptome analysis was optimized, but none of the available methods proved capable of removing dinoflagellate ribosomal RNA completely. RNAseq showed that a phasin encoding gene (phaP1) which is part of the polyhydroxyalkanoate (PHA) metabolism operon represented approximately 10% of all transcripts. Five genes for aerobic anoxygenic photosynthesis were down-regulated in the light, indicating that the photosynthesis apparatus was functional. A betaine-choline-carnitine-transporter (BCCT) that may be used for dimethylsulfoniopropionate (DMSP) uptake was the highest up-regulated gene in the light. The data suggest that at this early mutualistic phase of the symbiosis, PHA degradation might be the main carbon and energy source of D. shibae, supplemented in the light by degradation of DMSP and aerobic anoxygenic photosynthesis. PMID:25009539

  1. A dual-species co-cultivation system to study the interactions between Roseobacters and dinoflagellates.

    PubMed

    Wang, Hui; Tomasch, Jürgen; Jarek, Michael; Wagner-Döbler, Irene

    2014-01-01

    Some microalgae in nature live in symbiosis with microorganisms that can enhance or inhibit growth, thus influencing the dynamics of phytoplankton blooms. In spite of the great ecological importance of these interactions, very few defined laboratory systems are available to study them in detail. Here we present a co-cultivation system consisting of the toxic phototrophic dinoflagellate Prorocentrum minimum and the photoheterotrophic alphaproteobacterium Dinoroseobacter shibae. In a mineral medium lacking a carbon source, vitamins for the bacterium and the essential vitamin B12 for the dinoflagellate, growth dynamics reproducibly went from a mutualistic phase, where both algae and bacteria grow, to a pathogenic phase, where the algae are killed by the bacteria. The data show a "Jekyll and Hyde" lifestyle that had been proposed but not previously demonstrated. We used RNAseq and microarray analysis to determine which genes of D. shibae are transcribed and differentially expressed in a light dependent way at an early time-point of the co-culture when the bacterium grows very slowly. Enrichment of bacterial mRNA for transcriptome analysis was optimized, but none of the available methods proved capable of removing dinoflagellate ribosomal RNA completely. RNAseq showed that a phasin encoding gene (phaP1 ) which is part of the polyhydroxyalkanoate (PHA) metabolism operon represented approximately 10% of all transcripts. Five genes for aerobic anoxygenic photosynthesis were down-regulated in the light, indicating that the photosynthesis apparatus was functional. A betaine-choline-carnitine-transporter (BCCT) that may be used for dimethylsulfoniopropionate (DMSP) uptake was the highest up-regulated gene in the light. The data suggest that at this early mutualistic phase of the symbiosis, PHA degradation might be the main carbon and energy source of D. shibae, supplemented in the light by degradation of DMSP and aerobic anoxygenic photosynthesis. PMID:25009539

  2. Controlled Clinical Comparison of BacT/ALERT Standard Aerobic Medium with BACTEC Standard Aerobic Medium for Culturing Blood

    PubMed Central

    Mirrett, Stanley; Reller, L. Barth; Petti, Cathy A.; Woods, Christopher W.; Vazirani, Bindu; Sivadas, Rekha; Weinstein, Melvin P.

    2003-01-01

    Standard aerobic media are widely used for culturing blood with the BacT/ALERT (BioMérieux, Inc., Durham, N.C.) (BM) and BACTEC 9240 (BD Diagnostic Systems, Sparks, Md.) (BD) automated continuously monitoring instrument systems. Although similarly composed of soybean-casein digest broths, the formulations of the standard aerobic media available for these instruments differ from each other in supplements and in sodium polyanetholesulfonate concentration. Therefore, we compared the standard aerobic media available for these systems at two university hospitals. Blood samples from adult patients with suspected bloodstream infection were inoculated at the bedside into nonvented BM and BD standard aerobic blood culture bottles and incubated in their respective instruments. The laboratories received 6,743 pairs of bottles that were each filled with 8 to 12 ml of blood. A total of 523 isolates representing true infections were recovered from 257 patients; of these isolates, 348 were recovered from both the BD and the BM bottles, 108 were recovered from the BM bottles only, and 67 were recovered from the BD bottles only (P < 0.005). More staphylococci (P < 0.05), especially coagulase-negative staphylococci (P < 0.05), and yeasts (P < 0.01) were recovered from BM bottles than from BD bottles. Of 291 unimicrobial episodes of bloodstream infection, 220 were detected with both bottles, 41 were detected with the BM bottles only, and 30 were detected with the BD bottles only (difference not significant). Among 335 cultures that were positive in both bottles within the first 72 h of incubation, the median times to detection were 14 h for BM bottles and 13 h for BD bottles. Rates for false-positive results were 0.5% for BM bottles and 0.1% for BD bottles. One BM bottle and seven BD bottles yielded false-negative results. We conclude that the BM medium provides improved recovery of microorganisms, especially staphylococci and yeasts, compared with that provided by the BD medium

  3. Aeration control of thermophilic aerobic digestion using fluorescence monitoring.

    PubMed

    Kim, Young-Kee; Oh, Byung-Keun

    2009-01-01

    The thermophilic aerobic digestion (TAD) process is recognized as an effective method for rapid waste activated sludge (WAS) degradation and the deactivation of pathogenic microorganisms. Yet, high energy costs due to heating and aeration have limited the commercialization of economical TAD processes. Previous research on autothermal thermophilic aerobic digestion (ATAD) has already reduced the heating cost. However, only a few studies have focused on reducing the aeration cost. Therefore, this study applied a two-step aeration control strategy to a fill-and-draw mode semicontinuous TAD process. The NADH-dependent fluorescence was monitored throughout the TAD experiment, and the aeration rate shifted according to the fluorescence intensity. As a result, the simple two-step aeration control operation achieved a 20.3% reduction in the total aeration, while maintaining an effective and stable operation. It is also expected that more savings can be achieved with a further reduction of the lower aeration rate or multisegmentation of the aeration rate. PMID:19190414

  4. Toxic effects of butyl elastomers on aerobic methane oxidation

    NASA Astrophysics Data System (ADS)

    Niemann, Helge; Steinle, Lea I.; Blees, Jan H.; Krause, Stefan; Bussmann, Ingeborg; Lehmann, Moritz F.; Treude, Tina

    2013-04-01

    Large quantities of the potent greenhouse gas methane are liberated into the water column of marine and lacustrine environments where it may be consumed by aerobic methane oxidising bacteria before reaching the atmosphere.The reliable quantification of aerobic methane oxidation (MOx) rates is consequently of paramount importance for estimating methane budgets and to understand the controls on water column methane cycling. A widely used set of methods for measuring MOx rates is based on the incubation of water samples during which the consumption of methane is monitored, for instance with radio-tracer assays. Typically, incubation vessels are sealed with butyl rubber stoppers because these elastomers are essentially impermeable for gases at the relevant time scales. We tested the effect of different stopper materials (unmodified- and halogenated butyl rubber) on MOx activity in environmental samples and in cultures of methane oxidising bacteria. MOx rates in samples sealed with unmodified butyl rubber were > 75% lower compared to parallel incubations with halogenated butyl rubber seals, suggesting inhibiting/toxic effects associated with the use of unmodified butyl elastomers. To further explore the cause of these effects, we analysed aqueous extracts of the different stoppers. Halogenated butyl rubber stoppers appeared to bleed off comparably little amounts of organics. In stark contrast, extracts of unmodified butyl rubber were contaminated with various organic compounds including potential bactericides such as benzyltoluenes, phenylalkanes and benzuothiazoles. We also found tetramethylthiourea, a scavenger of active oxygen species, which may inhibit the MOx pathway.

  5. Biotechnology for aerobic conversion of food waste into organic fertilizer.

    PubMed

    Stabnikova, Olena; Ding, Hong-Bo; Tay, Joo-Hwa; Wang, Jing-Yuan

    2005-02-01

    A biotechnology for aerobic conversion of food waste into organic fertilizer under controlled aeration, stirring, pH and temperature at 55-65 degrees C, is proposed. To maintain neutral pH at the beginning of the bioconversion 5% CaCO3 was added to the total solids of the food waste. The addition of 20% horticultural waste compost as a bulking agent to the food wastes (w.w./w.w.), improved the bioconversion and increased the stability of the final product. No starter culture was needed for aerobic bioconversion of food waste into organic fertilizer for 10 days. The low contents of heavy metals in the raw materials used in the bioconversions ensured the safety of fertilizer from food waste for application in agriculture. The addition of 4% organic fertilizer to the subsoil increased the yield and growth of Ipomoea aquatica (Kang Kong) by 1.5 to 2 times. The addition of phosphorus is required to enhance the positive effect of organic fertilizer on plant growth. PMID:15751394

  6. Efficient utilization of aerobic metabolism helps Tibetan locusts conquer hypoxia

    PubMed Central

    2013-01-01

    Background Responses to hypoxia have been investigated in many species; however, comparative studies between conspecific geographical populations at different altitudes are rare, especially for invertebrates. The migratory locust, Locusta migratoria, is widely distributed around the world, including on the high-altitude Tibetan Plateau (TP) and the low-altitude North China Plain (NP). TP locusts have inhabited Tibetan Plateau for over 34,000 years and thus probably have evolved superior capacity to cope with hypoxia. Results Here we compared the hypoxic responses of TP and NP locusts from morphological, behavioral, and physiological perspectives. We found that TP locusts were more tolerant of extreme hypoxia than NP locusts. To evaluate why TP locusts respond to extreme hypoxia differently from NP locusts, we subjected them to extreme hypoxia and compared their transcriptional responses. We found that the aerobic metabolism was less affected in TP locusts than in NP locusts. RNAi disruption of PDHE1β, an entry gene from glycolysis to TCA cycle, increased the ratio of stupor in TP locusts and decreased the ATP content of TP locusts in hypoxia, confirming that aerobic metabolism is critical for TP locusts to maintain activity in hypoxia. Conclusions Our results indicate that TP and NP locusts have undergone divergence in hypoxia tolerance. These findings also indicate that insects can adapt to hypoxic pressure by modulating basic metabolic processes. PMID:24047108

  7. Roles of triosephosphate isomerase and aerobic metabolism in Trypanosoma brucei.

    PubMed Central

    Helfert, S; Estévez, A M; Bakker, B; Michels, P; Clayton, C

    2001-01-01

    Kinetoplastid protozoa compartmentalize the first seven enzymes of glycolysis and two enzymes of glycerol metabolism in a microbody, the glycosome. While in its mammalian host, Trypanosoma brucei depends entirely on glucose for ATP generation. Under aerobic conditions, most of the glucose is metabolized to pyruvate. Aerobic metabolism depends on the activities of glycosomal triosephosphate isomerase and a mitochondrial glycerophosphate oxidase, and on glycerophosphate<-->dihydroxyacetone phosphate exchange across the glycosomal membrane. Using a combination of genetics and computer modelling, we show that triosephosphate isomerase is probably essential for bloodstream trypanosome survival, but not for the insect-dwelling procyclics, which preferentially use amino acids as an energy source. When the enzyme level decreased to about 15% of that of the wild-type, the growth rate was halved. Below this level, a lethal rise in dihydroxyacetone phosphate was predicted. Expression of cytosolic triosephosphate isomerase inhibited cell growth. Attempts to knockout the trypanosome alternative oxidase genes (which are needed for glycerophosphate oxidase activity) were unsuccessful, but when we lowered the level of the corresponding mRNA by expressing a homologous double-stranded RNA, oxygen consumption was reduced fourfold and the rate of trypanosome growth was halved. PMID:11415442

  8. On Aerobic Exercise and Behavioral and Neural Plasticity

    PubMed Central

    Swain, Rodney A.; Berggren, Kiersten L.; Kerr, Abigail L.; Patel, Ami; Peplinski, Caitlin; Sikorski, Angela M.

    2012-01-01

    Aerobic exercise promotes rapid and profound alterations in the brain. Depending upon the pattern and duration of exercise, these changes in the brain may extend beyond traditional motor areas to regions and structures normally linked to learning, cognition, and emotion. Exercise-induced alterations may include changes in blood flow, hormone and growth factor release, receptor expression, angiogenesis, apoptosis, neurogenesis, and synaptogenesis. Together, we believe that these changes underlie elevations of mood and prompt the heightened behavioral plasticity commonly observed following adoption of a chronic exercise regimen. In the following paper, we will explore both the psychological and psychobiological literatures relating to exercise effects on brain in both human and non-human animals and will attempt to link plastic changes in these neural structures to modifications in learned behavior and emotional expression. In addition, we will explore the therapeutic potential of exercise given recent reports that aerobic exercise may serve as a neuroprotectant and can also slow cognitive decline during normal and pathological aging. PMID:24961267

  9. Cultivation of aerobic granular sludge for rubber wastewater treatment.

    PubMed

    Rosman, Noor Hasyimah; Nor Anuar, Aznah; Othman, Inawati; Harun, Hasnida; Sulong Abdul Razak, Muhammad Zuhdi; Elias, Siti Hanna; Mat Hassan, Mohd Arif Hakimi; Chelliapan, Shreesivadass; Ujang, Zaini

    2013-02-01

    Aerobic granular sludge (AGS) was successfully cultivated at 27±1 °C and pH 7.0±1 during the treatment of rubber wastewater using a sequential batch reactor system mode with complete cycle time of 3 h. Results showed aerobic granular sludge had an excellent settling ability and exhibited exceptional performance in the organics and nutrients removal from rubber wastewater. Regular, dense and fast settling granule (average diameter, 1.5 mm; settling velocity, 33 m h(-1); and sludge volume index, 22.3 mL g(-1)) were developed in a single reactor. In addition, 96.5% COD removal efficiency was observed in the system at the end of the granulation period, while its ammonia and total nitrogen removal efficiencies were up to 94.7% and 89.4%, respectively. The study demonstrated the capabilities of AGS development in a single, high and slender column type-bioreactor for the treatment of rubber wastewater. PMID:23317554

  10. Aerobic and anaerobic PCB biodegradation in the environment

    SciTech Connect

    Abramowicz, D.A.

    1995-06-01

    Studies have identified two distinct biological processes capable of biotransforming polychlorinated biphenyls (PCBs): aerobic oxidative processes and anaerobic reductive processes. It is now known that these two complementary activities are occurring naturally in the environment. Anaerobic PCB dechlorination, responsible for the conversion of highly chlorinated PCBs to lightly chlorinated ortho-enriched congeners, has been documented extensively in the Hudson River and has been observed at many other sites throughout the world. The products from this anaerobic process are readily degradable by a wide range of aerobic bacteria, and it has now been shown that this process is occurring in surficial sediments in the Hudson River. The widespread anaerobic dechlorination of PCBs that has been observed in many river and marine sediments results in reduction of both the potential risk from and potential exposure to PCBs. The reductions in potential risk include reduced dioxin like toxicity and reduced carcinogenicity. The reduced PCB exposure realized upon dechlorination is manifested by reduced bioaccumulation in the food chain and by the increased anaerobic degradability of these products. 27 refs., 1 fig., 1 tab.

  11. Cardiovascular response to dynamic aerobic exercise: a mathematical model.

    PubMed

    Magosso, E; Ursino, M

    2002-11-01

    An original mathematical model of the cardiovascular response to dynamic exercise is presented. It includes the pulsating heart, the pulmonary and systemic circulation, a separate description of the vascular bed in active tissues, the local metabolic vasodilation in these tissues and the mechanical effects of muscular contractions on venous return. Moreover, the model provides a description of the ventilatory response to exercise and various neural regulatory mechanisms working on cardiovascular parameters. These mechanisms embrace the so-called central command, the arterial baroreflex and the lung inflation reflex. All parameters in the model have been given in accordance with physiological data from the literature. In this work, the model has been used to simulate the steady-state value of the main cardiorespiratory quantities at different levels of aerobic exercise and the temporal pattern in the transient phase from rest to moderate exercise. Results suggest that, with suitable parameter values the model is able accurately to simulate the cardiorespiratory response in the overall range of aerobic exercise. This response is characterised by a moderate hypertension (10-30%) and by a conspicuous increase in systemic conductance (80-130%), heart rate (64-150%) and cardiac output (100-200%). The transient pattern exhibits three distinct phases (lasting approximately 5s, 15s and 2 min), that reflect the temporal heterogeneity of the mechanisms involved. The model may be useful to improve understanding of exercise physiology and as an educational tool to analyse the complexity of cardiovascular and respiratory regulation. PMID:12507317

  12. Critical period of weed control in aerobic rice.

    PubMed

    Anwar, M P; Juraimi, A S; Samedani, B; Puteh, A; Man, A

    2012-01-01

    Critical period of weed control is the foundation of integrated weed management and, hence, can be considered the first step to design weed control strategy. To determine critical period of weed control of aerobic rice, field trials were conducted during 2010/2011 at Universiti Putra Malaysia. A quantitative series of treatments comprising two components, (a) increasing duration of weed interference and (b) increasing length of weed-free period, were imposed. Critical period was determined through Logistic and Gompertz equations. Critical period varied between seasons; in main season, it started earlier and lasted longer, as compared to off-season. The onset of the critical period was found relatively stable between seasons, while the end was more variable. Critical period was determined as 7-49 days after seeding in off-season and 7-53 days in main season to achieve 95% of weed-free yield, and 23-40 days in off-season and 21-43 days in main season to achieve 90% of weed-free yield. Since 5% yield loss level is not practical from economic view point, a 10% yield loss may be considered excellent from economic view point. Therefore, aerobic rice should be kept weed-free during 21-43 days for better yield and higher economic return. PMID:22778701

  13. [Optimization of aerobic/anaerobic subsurface flow constructed wetlands].

    PubMed

    Li, Feng-Min; Shan, Shi; Li, Yuan-Yuan; Li, Yang; Wang, Zheng-Yu

    2012-02-01

    Previous studies showed that setting aerobic and anaerobic paragraph segments in the subsurface constructed wetlands (SFCWs) can improve the COD, NH4(+)-N, and TN removal rate, whereas the oxygen enrichment environment which produced by the artificial aeration could restrain the NO3(-)-N and NO2(-)-N removal process, and to a certain extent, inhibit the denitrification in SFCWs Therefore, in this research the structure and technology of SFCW with aerobic and anaerobic paragraph segments were optimized, by using the multi-point water inflow and setting the corresponding section for the extra pollutant removal. Results showed that with the hydraulic load of 0.06 m3 x (m2 x d)(-1), the COD, NH4(+)-N and TN removal efficiencies in the optimized SFCW achieved 91.6%, 100% and 87.7% respectively. COD/N increased to 10 speedily after the inflow supplement. The multi-point water inflow could add carbon sources, and simultaneously maximum utilization of wetland to remove pollutants. The optimized SFCW could achieve the purposes of purification process optimization, and provide theoretical basis and application foundation for improving the total nitrogen removal efficiency. PMID:22509578

  14. Improved Aerobic Colony Count Technique for Hydrophobic Grid Membrane Filters

    PubMed Central

    Parrington, Lorna J.; Sharpe, Anthony N.; Peterkin, Pearl I.

    1993-01-01

    The AOAC International official action procedure for performing aerobic colony counts on hydrophobic grid membrane filters (HGMFs) uses Trypticase soy-fast green FCF agar (FGA) incubated for 48 h. Microbial growths are various shades of green on a pale green background, which can cause problems for automated as well as manual counting. HGMFs which had been incubated 24 or 48 h at 35°C on Trypticase soy agar were flooded underneath with 1 to 2 ml of 0.1% triphenyltetrazolium chloride (TTC) solution by simply lifting one corner of the filter while it was still on the agar and adding the reagent. Microbial growths on HGMFs were counted after color had been allowed to develop for 15 min at room temperature. With representative foods, virtually all colonies stained pink to red. Automated electronic counts made by using the MI-100 HGMF Interpreter were easier and more reliable than control HGMF counts made by the AOAC International official action procedure. Manual counting was easier as well because of increased visibility of the microbial growths. Except in the case of dairy products, 24-h TTC counts did not differ significantly from 48-h FGA counts, whereas the FGA counts at 24 h were always significantly lower, indicating that for many food products the HGMF TTC flooding method permits aerobic colony counts to be made after 24 h. PMID:16349033

  15. Progressive hypoxia decouples activity and aerobic performance of skate embryos

    PubMed Central

    Di Santo, Valentina; Tran, Anna H.; Svendsen, Jon C.

    2016-01-01

    Although fish population size is strongly affected by survival during embryonic stages, our understanding of physiological responses to environmental stressors is based primarily on studies of post-hatch fishes. Embryonic responses to acute exposure to changes in abiotic conditions, including increase in hypoxia, could be particularly important in species exhibiting long developmental time, as embryos are unable to select a different environment behaviourally. Given that oxygen is key to metabolic processes in fishes and aquatic hypoxia is becoming more severe and frequent worldwide, organisms are expected to reduce their aerobic performance. Here, we examined the metabolic and behavioural responses of embryos of a benthic elasmobranch fish, the little skate (Leucoraja erinacea), to acute progressive hypoxia, by measuring oxygen consumption and movement (tail-beat) rates inside the egg case. Oxygen consumption rates were not significantly affected by ambient oxygen levels until reaching 45% air saturation (critical oxygen saturation, Scrit). Below Scrit, oxygen consumption rates declined rapidly, revealing an oxygen conformity response. Surprisingly, we observed a decoupling of aerobic performance and activity, as tail-beat rates increased, rather than matching the declining metabolic rates, at air saturation levels of 55% and below. These results suggest a significantly divergent response at the physiological and behavioural levels. While skate embryos depressed their metabolic rates in response to progressive hypoxia, they increased water circulation inside the egg case, presumably to restore normoxic conditions, until activity ceased abruptly around 9.8% air saturation. PMID:27293746

  16. Maximum Aerobic Capacity of Underground Coal Miners in India

    PubMed Central

    Saha, Ratnadeep; Dey, Netai Chandra; Samanta, Amalendu; Biswas, Rajib

    2011-01-01

    Miners fitness test was assessed in terms of determination of maximum aerobic capacity by an indirect method following a standard step test protocol before going down to mine by taking into consideration of heart rates (Telemetric recording) and oxygen consumption of the subjects (Oxylog-II) during exercise at different working rates. Maximal heart rate was derived as 220−age. Coal miners reported a maximum aerobic capacity within a range of 35–38.3 mL/kg/min. It also revealed that oldest miners (50–59 yrs) had a lowest maximal oxygen uptake (34.2 ± 3.38 mL/kg/min) compared to (42.4 ± 2.03 mL/kg/min) compared to (42.4 ± 2.03 mL/kg/min) the youngest group (20–29 yrs). It was found to be negatively correlated with age (r = −0.55 and −0.33 for younger and older groups respectively) and directly associated with the body weight of the subjects (r = 0.57 – 0.68, P ≤ 0.001). Carriers showed maximum cardio respiratory capacity compared to other miners. Indian miners VO2max was found to be lower both compared to their abroad mining counterparts and various other non-mining occupational working groups in India. PMID:21961020

  17. Kibdelomycin Is a Bactericidal Broad-Spectrum Aerobic Antibacterial Agent

    PubMed Central

    Dayananth, Priya; Balibar, Carl J.; Garlisi, Charles G.; Lu, Jun; Kishii, Ryuta; Takei, Masaya; Fukuda, Yasumichi; Ha, Sookhee; Young, Katherine

    2015-01-01

    Bacterial resistance to antibiotics continues to grow and pose serious challenges, while the discovery rate for new antibiotics declines. Kibdelomycin is a recently discovered natural-product antibiotic that inhibits bacterial growth by inhibiting the bacterial DNA replication enzymes DNA gyrase and topoisomerase IV. It was reported to be a broad-spectrum aerobic Gram-positive agent with selective inhibition of the anaerobic bacterium Clostridium difficile. We have extended the profiling of kibdelomycin by using over 196 strains of Gram-positive and Gram-negative aerobic pathogens recovered from worldwide patient populations. We report the MIC50s, MIC90s, and bactericidal activities of kibdelomycin. We confirm the Gram-positive spectrum and report for the first time that kibdelomycin shows strong activity (MIC90, 0.125 μg/ml) against clinical strains of the Gram-negative nonfermenter Acinetobacter baumannii but only weak activity against Pseudomonas aeruginosa. We confirm that well-characterized resistant strains of Staphylococcus aureus and Streptococcus pneumoniae show no cross-resistance to kibdelomycin and quinolones and coumarin antibiotics. We also show that kibdelomycin is not subject to efflux in Pseudomonas, though it is in Escherichia coli, and it is generally affected by the outer membrane permeability entry barrier in the nonfermenters P. aeruginosa and A. baumannii, which may be addressable by structure-based chemical modification. PMID:25845866

  18. Nitroglycerin degradation mediated by soil organic carbon under aerobic conditions.

    PubMed

    Bordeleau, Geneviève; Martel, Richard; Bamba, Abraham N'Valoua; Blais, Jean-François; Ampleman, Guy; Thiboutot, Sonia

    2014-10-01

    The presence of nitroglycerin (NG) has been reported in shallow soils and pore water of several military training ranges. In this context, NG concentrations can be reduced through various natural attenuation processes, but these have not been thoroughly documented. This study aimed at investigating the role of soil organic matter (SOM) in the natural attenuation of NG, under aerobic conditions typical of shallow soils. The role of SOM in NG degradation has already been documented under anoxic conditions, and was attributed to SOM-mediated electron transfer involving different reducing agents. However, unsaturated soils are usually well-oxygenated, and it was not clear whether SOM could participate in NG degradation under these conditions. Our results from batch- and column-type experiments clearly demonstrate that in presence of dissolved organic matter (DOM) leached from a natural soil, partial NG degradation can be achieved. In presence of particulate organic matter (POM) from the same soil, complete NG degradation was achieved. Furthermore, POM caused rapid sorption of NG, which should result in NG retention in the organic matter-rich shallow horizons of the soil profile, thus promoting degradation. Based on degradation products, the reaction pathway appears to be reductive, in spite of the aerobic conditions. The relatively rapid reaction rates suggest that this process could significantly participate in the natural attenuation of NG, both on military training ranges and in contaminated soil at production facilities. PMID:25086776

  19. Aerobic biotransformation of polybrominated diphenyl ethers (PBDEs) by bacterial isolates

    PubMed Central

    Robrock, Kristin R.; Coelhan, Mehmet; Sedlak, David; Alvarez-Cohen, Lisa

    2009-01-01

    Polybrominated diphenyl ethers (PBDEs) are flame retardants that have been used in consumer products and furniture for three decades. Currently, very little is known about their fate in the environment and specifically about their susceptibility to aerobic biotransformation. Here, we investigated the ability of the polychlorinated biphenyl (PCB) degrading bacteria Rhodococcus jostii RHA1 and Burkholderia xenovorans LB400 to transform mono- through hexa-BDEs at ppb levels. We also tested the PBDE transforming abilities of related strain Rhodococcus sp. RR1 and the ether-degrading Pseudonocardia dioxanivorans CB1190. The two PCB-degrading strains transformed all of the mono- through penta-BDEs and strain LB400 transformed one of the hexa-BDEs. The extent of transformation was inversely proportional to the degree of bromination. Strains RR1 and CB1190 were only able to transform the less brominated mono- and di- BDE congeners. RHA1 released stoichiometric quantities of bromide while transforming mono- and tetra-BDE congeners. LB400 instead converted most of a mono-BDE to a hydroxylated mono-BDE. This is the first report of aerobic transformation of tetra-, penta- and hexa-BDEs as well as the first report of stoichiometric release of bromide during PBDE transformation. PMID:19731666

  20. Balinese dance exercises improve the maximum aerobic capacity.

    PubMed

    Adiputra, N; Alex, P; Sutjana, D P; Tirtayasa, K; Manuaba, A

    1996-06-01

    The maximum aerobic capacity can be used to predict the maximum working capacity. The maximum working capacity plays an important role in achieving the best performance. Therefore, physical fitness program for maintaining maximum working capacity is a must. A study on the application of Balinese dance exercise was carried out. Sixty young male Balinese, aged from 17 to 19 years were used as subjects. They were divided into two groups: Experimental group (EG) and control group (CG) based on their VO2max. The EG participated in a program of Balinese dance exercise 3 x 50 min per week for 8 weeks. Pretest-posttest control group design was applied. The maximum aerobic capacity was measured, based on the Modified Harvard Step-up Test and nomogram of Astrand. The results are as follows: there is a very significant improvement of VO2max from 2.7 +/- 0.5 l/min or 51.1 +/- 9.1 ml/kg/min into 3.1 +/- 0.5 l/min or 58.9 +/- 9.8 ml/kg/min. Other parameters such as resting heart rate, blood pressure and percent body fat were decreased significantly. The study concludes that Balinese dance exercise could be used as a program for physical fitness maintenance. PMID:9551128

  1. Comparison of sidestream treatment technologies: post aerobic digestion and Anammox.

    PubMed

    Bauer, Heidi; Johnson, Thomas D; Johnson, Bruce R; Oerke, David; Graziano, Steven

    2016-01-01

    Post aerobic digestion (PAD) and anaerobic ammonium oxidation (Anammox) are sidestream treatment technologies which are both excellent options for the reduction of nitrogen recycled back to the liquid stream without the need for supplemental carbon or alkalinity. However, the achievement of this goal is where the similarities between the two technologies end. PAD is an advanced digestion process where aerobic digestion is designed to follow anaerobic digestion. Other benefits of PAD include volatile solids reduction, odor reduction, and struvite formation reduction. Anammox harnesses a specific species of autotrophic bacteria that can help achieve partial nitritation/deammonification. Other benefits of Anammox include lower energy consumption due to requiring less oxygen compared with conventional nitrification. This manuscript describes the unique benefits and challenges of each technology. Example installations are presented with a narrative of how and why the technology was selected. A whole plant simulator is used to compare and contrast the mass balances and net present value costs on an 'apples to apples' basis. The discussion includes descriptions of conditions under which each technology would potentially be the most beneficial and cost-effective against a baseline facility without sidestream treatment. PMID:27232417

  2. Anaerobic Metabolism: Linkages to Trace Gases and Aerobic Processes

    NASA Astrophysics Data System (ADS)

    Megonigal, J. P.; Hines, M. E.; Visscher, P. T.

    2003-12-01

    Life evolved and flourished in the absence of molecular oxygen (O2). As the O2 content of the atmosphere rose to the present level of 21% beginning about two billion years ago, anaerobic metabolism was gradually supplanted by aerobic metabolism. Anaerobic environments have persisted on Earth despite the transformation to an oxidized state because of the combined influence of water and organic matter. Molecular oxygen diffuses about 104 times more slowly through water than air, and organic matter supports a large biotic O2 demand that consumes the supply faster than it is replaced by diffusion. Such conditions exist in wetlands, rivers, estuaries, coastal marine sediments, aquifers, anoxic water columns, sewage digesters, landfills, the intestinal tracts of animals, and the rumen of herbivores. Anaerobic microsites are also embedded in oxic environments such as upland soils and marine water columns. Appreciable rates of aerobic respiration are restricted to areas that are in direct contact with air or those inhabited by organisms that produce O2.Rising atmospheric O2 reduced the global area of anaerobic habitat, but enhanced the overall rate of anaerobic metabolism (at least on an area basis) by increasing the supply of electron donors and acceptors. Organic carbon production increased dramatically, as did oxidized forms of nitrogen, manganese, iron, sulfur, and many other elements. In contemporary anaerobic ecosystems, nearly all of the reducing power is derived from photosynthesis, and most of it eventually returns to O2, the most electronegative electron acceptor that is abundant. This photosynthetically driven redox gradient has been thoroughly exploited by aerobic and anaerobic microorganisms for metabolism. The same is true of hydrothermal vents (Tunnicliffe, 1992) and some deep subsurface environments ( Chapelle et al., 2002), where thermal energy is the ultimate source of the reducing power.Although anaerobic habitats are currently a small fraction of Earth

  3. Aerobic Requirements for Moving Handweights through Various Ranges of Motion While Walking.

    ERIC Educational Resources Information Center

    Auble, Thomas E.; And Others

    1987-01-01

    Comparison of the aerobic metabolic requirements of normal walking with and without 1-, 2-, and 3-pound handweights among nine adult males indicated that walking while moving handweights through large ranges of motion provides a combined upper and lower body aerobic stimulus that is sufficient for endurance training for persons with poor to…

  4. ENVIRONMENTAL REGULATIONS AND TECHNOLOGY - AUTOTHERMAL THERMOPHILIC AEROBIC DIGESTION OF MUNICIPAL WASTEWATER SLUDGE

    EPA Science Inventory

    This document describes a promising technology — autothermal thermophilic aerobic digestion — for meeting the current and proposed U.S. federal requirements for pathogen controJ and land application of municipal wastewater sludge. Autothermal thermophilic aerobic digestion, or AT...

  5. Steps Counts among Middle School Students Vary with Aerobic Fitness Level

    ERIC Educational Resources Information Center

    Le Masurier, Guy C.; Corbin, Charles B.

    2006-01-01

    The purpose of this study was to examine if steps/day taken by middle school students varied based on aerobic fitness classification. Middle school students (N = 223; 112 girls, 111 boys) were assigned to three aerobic fitness categories (HIGH, MOD, LOW) based on results of the FITNESSGRAM PACER test. Four weekdays of pedometer monitoring…

  6. The Effect of Four Instructional Formats on Aerobic Fitness of Junior-High School Students

    ERIC Educational Resources Information Center

    Wright, Ron W.; Karp, Grace Goc

    2006-01-01

    The low level of fitness in junior-high school students is an area of great concern. An important, but misunderstood, part of the physical education curriculum is the development of aerobic fitness. What is the best way to go about developing aerobic fitness? Four groups of primarily Caucasian (79.9%) Grade 8 and 9 students (n = 144), attending a…

  7. Associations between Attitudes toward Physical Education and Aerobic Capacity in Hungarian High School Students

    ERIC Educational Resources Information Center

    Kaj, Mónika; Saint-Maurice, Pedro F.; Karsai, István; Vass, Zoltán; Csányi, Tamás; Boronyai, Zoltán; Révész, László

    2015-01-01

    Purpose: The purpose of this study was to create a physical education (PE) attitude scale and examine how it is associated with aerobic capacity (AC). Method: Participants (n = 961, aged 15-20 years) were randomly selected from 26 Hungarian high schools. AC was estimated from performance on the Progressive Aerobic Cardiovascular and Endurance Run…

  8. Cardiac Frequency and Caloric Cost of Aerobic Dancing in Young Women.

    ERIC Educational Resources Information Center

    Nelson, Deborah J.; And Others

    1988-01-01

    A study of cardiac frequency during aerobic dancing indicated that it can sustain an elevated cardiac frequency in most cases. The caloric cost of aerobic dancing is approximately 50 percent greater than an equal duration of barre and center-floor exercise by elite ballet dancers. (JD)

  9. Active Female Maximal and Anaerobic Threshold Cardiorespiratory Responses to Six Different Water Aerobics Exercises

    ERIC Educational Resources Information Center

    Antunes, Amanda H.; Alberton, Cristine L.; Finatto, Paula; Pinto, Stephanie S.; Cadore, Eduardo L.; Zaffari, Paula; Kruel, Luiz F. M.

    2015-01-01

    Purpose: Maximal tests conducted on land are not suitable for the prescription of aquatic exercises, which makes it difficult to optimize the intensity of water aerobics classes. The aim of the present study was to evaluate the maximal and anaerobic threshold cardiorespiratory responses to 6 water aerobics exercises. Volunteers performed 3 of the…

  10. Carbon offsets from improved swine manure management using aerobic treatment technology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aerobic treatment of manure is an accepted manure management system under protocols adopted through the United Nations Framework Convention on Climate Change (UNFCCC). Our objectives were to determine greenhouse gas (GHG) emission reductions from replacement of anaerobic lagoons with aerobic treatme...

  11. Noise Levels during Aerobics and the Potential Effects on Distortion Product Otoacoustic Emissions

    ERIC Educational Resources Information Center

    Torre, Peter, III; Howell, Jennifer C.

    2008-01-01

    The purpose of this study was to measure noise levels during aerobics classes and to examine how outer hair cell (OHC) function, using distortion product otoacoustic emissions (DPOAEs), may be affected by this exposure. Fifty individuals (48 women and 2 men, ages 19-41 years) participated in 50-min aerobics classes. Noise levels were measured…

  12. Effects of anaerobic digestion and aerobic treatment on gaseous emissions from dairy manure storages

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Effects of anaerobic digestion and aerobic treatment on the reduction of gaseous emissions from dairy manure storages were evaluated in this study. Screened dairy manure containing 3.5% volatile solids (VS) was either anaerobically digested or aerobically treated prior to storage in air-tight vessel...

  13. Anaerobic-aerobic sequencing bioreactors improve energy efficiency for treatment of personal care product industry wastes.

    PubMed

    Ahammad, S Z; Bereslawski, J L; Dolfing, J; Mota, C; Graham, D W

    2013-07-01

    Personal care product (PCP) industry liquid wastes contain shampoo residues, which are usually treated by aerobic activated sludge (AS). Unfortunately, AS is expensive for PCP wastes because of high aeration and energy demands, whereas potentially energy-positive anaerobic designs cannot meet effluent targets. Therefore, combined anaerobic-aerobic systems may be the best solution. Seven treatment systems were assessed in terms of energy and treatment performance for shampoo wastes, including one aerobic, three anaerobic (HUASB, AHR and AnCSTR) and three anaerobic-aerobic reactor designs. COD removals were highest in the HUASB-aerobic (87.9 ± 0.4%) and AHR-aerobic (86.8±0.5%) systems, which used 69.2% and 62.5% less energy than aerobic AS. However, actual methane production rates were low relative to theoretical in the UASB and AHR units (∼10% methane/COD removed) compared with the AnCSTR unit (∼70%). Anaerobic-aerobic sequence reactors show promise for treating shampoo wastes, but optimal designs depend upon whether methane production or COD removal is most important to operations. PMID:23639409

  14. Sweat Rates During Continuous and Interval Aerobic Exercise: Implications for NASA Multipurpose Crew Vehicle (MPCV) Missions

    NASA Technical Reports Server (NTRS)

    Ryder, Jeffrey W.; Scott, Jessica; Ploutz-Snyder, Robert; Ploutz-Snyder, Lori L.

    2016-01-01

    Aerobic deconditioning is one of the effects spaceflight. Impaired crewmember performance due to loss of aerobic conditioning is one of the risks identified for mitigation by the NASA Human Research Program. Missions longer than 8 days will involve exercise countermeasures including those aimed at preventing the loss of aerobic capacity. The NASA Multipurpose Crew Vehicle (MPCV) will be NASA's centerpiece architecture for human space exploration beyond low Earth orbit. Aerobic exercise within the small habitable volume of the MPCV is expected to challenge the ability of the environmental control systems, especially in terms of moisture control. Exercising humans contribute moisture to the environment by increased respiratory rate (exhaling air at 100% humidity) and sweat. Current acceptable values are based on theoretical models that rely on an "average" crew member working continuously at 75% of their aerobic capacity (Human Systems Integration Requirements Document). Evidence suggests that high intensity interval exercise for much shorter durations are equally effective or better in building and maintaining aerobic capacity. This investigation will examine sweat and respiratory rates for operationally relevant continuous and interval aerobic exercise protocols using a variety of different individuals. The results will directly inform what types of aerobic exercise countermeasures will be feasible to prescribe for crewmembers aboard the MPCV.

  15. Sweat Rates During Continuous and Interval Aerobic Exercise: Implications for NASA Multipurpose Crew Vehicle (MPCV) Missions

    NASA Technical Reports Server (NTRS)

    Ryder, Jeffrey W.; Scott, Jessica; Ploutz-Snyder, Lori L.

    2016-01-01

    Aerobic deconditioning is one of the effects spaceflight. Impaired crewmember performance due to loss of aerobic conditioning is one of the risks identified for mitigation by the NASA Human Research Program. Missions longer than 8 days will involve exercise countermeasures including those aimed at preventing the loss of aerobic capacity. The NASA Multipurpose Crew Vehicle (MPCV) will be NASA's centerpiece architecture for human space exploration beyond low Earth orbit. Aerobic exercise within the small habitable volume of the MPCV is expected to challenge the ability of the Air Revitalization System, especially in terms of moisture and temperature control. Exercising humans contribute moisture to the environment by increased respiratory rate (exhaling air saturated with moisture) and sweat. Current acceptable values are based on theoretical models that rely on an "average" crew member working continuously at 75% of their aerobic capacity (Human Systems Integration Requirements Document). Evidence suggests that high intensity interval exercise for much shorter durations are equally effective or better in building and maintaining aerobic capacity. This investigation will examine metabolic moisture and heat production for operationally relevant continuous and interval aerobic exercise protocols. The results will directly inform what types of aerobic exercise countermeasures will be feasible to prescribe for crewmembers aboard the MPCV.

  16. We Huff and Puff: The Parameters and the Program of Aerobics for Children under Five.

    ERIC Educational Resources Information Center

    Eastman, Wayne

    In today's society, young children have few experiences with aerobic activities, a pattern of exercise traditionally reserved for adults. This paper discusses how aerobic exercises can be used in a preschool environment, arguing that such activities are best presented using a thematic approach so that young children can form impressions about…

  17. Degradation of TCE using sequential anaerobic biofilm and aerobic immobilized bed reactor

    NASA Technical Reports Server (NTRS)

    Chapatwala, Kirit D.; Babu, G. R. V.; Baresi, Larry; Trunzo, Richard M.

    1995-01-01

    Bacteria capable of degrading trichloroethylene (TCE) were isolated from contaminated wastewaters and soil sites. The aerobic cultures were identified as Pseudomonas aeruginosa (four species) and Pseudomonas fluorescens. The optimal conditions for the growth of aerobic cultures were determined. The minimal inhibitory concentration values of TCE for Pseudomonas sps. were also determined. The aerobic cells were immobilized in calcium alginate in the form of beads. Degradation of TCE by the anaerobic and dichloroethylene (DCE) by aerobic cultures was studied using dual reactors - anaerobic biofilm and aerobic immobilized bed reactor. The minimal mineral salt (MMS) medium saturated with TCE was pumped at the rate of 1 ml per hour into the anaerobic reactor. The MMS medium saturated with DCE and supplemented with xylenes and toluene (3 ppm each) was pumped at the rate of 1 ml per hour into the fluidized air-uplift-type reactor containing the immobilized aerobic cells. The concentrations of TCE and DCE and the metabolites formed during their degradation by the anaerobic and aerobic cultures were monitored by GC. The preliminary study suggests that the anaerobic and aerobic cultures of our isolates can degrade TCE and DCE.

  18. Effects of Aerobic Training on Primary Dysmenorrhea Symptomatology in College Females.

    ERIC Educational Resources Information Center

    Israel, Richard G.; And Others

    1985-01-01

    This study investigated the effects of a 12-week aerobic training program on menstrual distress symptoms in college females with clinically diagnosed primary dysmenorrhea. The findings suggest that aerobic training can significantly reduce the symptoms associated with primary dysmenorrhea. (Author/MT)

  19. Aerobic exercise increases peripheral and hepatic insulin sensitivity in sedentary adolescents

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Data are limited on the effects of controlled aerobic exercise programs (without weight loss) on insulin sensitivity and glucose metabolism in children and adolescents. To determine whether a controlled aerobic exercise program (without weight loss) improves peripheral and hepatic insulin sensitivi...

  20. Reliability and Validity of Self Report of Aerobic Activity: Family Health Project.

    ERIC Educational Resources Information Center

    Baranowski, Tom; And Others

    1984-01-01

    Two studies are presented which deal with reliability and validity of self-reports of aerobic activity. The goal of these studies was to develop and test a form that could be used in a behavior modification program designed to increase aerobic activity among healthy families. (Author/DF)

  1. Aerobic N2O emission for activated sludge acclimated under different aeration rates in the multiple anoxic and aerobic process.

    PubMed

    Wang, Huoqing; Guan, Yuntao; Pan, Min; Wu, Guangxue

    2016-05-01

    Nitrous oxide (N2O) is a potent greenhouse gas that can be emitted during biological nitrogen removal. N2O emission was examined in a multiple anoxic and aerobic process at the aeration rates of 600mL/min sequencing batch reactor (SBRL) and 1200mL/min (SBRH). The nitrogen removal percentage was 89% in SBRL and 71% in SBRH, respectively. N2O emission mainly occurred during the aerobic phase, and the N2O emission factor was 10.1% in SBRL and 2.3% in SBRH, respectively. In all batch experiments, the N2O emission potential was high in SBRL compared with SBRH. In SBRL, with increasing aeration rates, the N2O emission factor decreased during nitrification, while it increased during denitrification and simultaneous nitrification and denitrification (SND). By contrast, in SBRH the N2O emission factor during nitrification, denitrification and SND was relatively low and changed little with increasing aeration rates. The microbial competition affected the N2O emission during biological nitrogen removal. PMID:27155411

  2. Grey water treatment in a series anaerobic--aerobic system for irrigation.

    PubMed

    Abu Ghunmi, Lina; Zeeman, Grietje; Fayyad, Manar; van Lier, Jules B

    2010-01-01

    This study aims at treatment of grey water for irrigation, focusing on a treatment technology that is robust, simple to operate and with minimum energy consumption. The result is an optimized system consisting of an anaerobic unit operated in upflow mode, with a 1 day operational cycle, a constant effluent flow rate and varying liquid volume. Subsequent aerobic step is equipped with mechanical aeration and the system is insulated for sustaining winter conditions. The COD removal achieved by the anaerobic and aerobic units in summer and winter are 45%, 39% and 53%, 64%, respectively. Sludge in the anaerobic and aerobic reactor has a concentration of 168 and 8 mg VSL(-1), respectively. Stability of sludge in the anaerobic and aerobic reactors is 80% and 93%, respectively, based on COD. Aerobic effluent quality, except for pathogens, agrees with the proposed irrigation water quality guidelines for reclaimed water in Jordan. PMID:19699088

  3. Little left in the tank: metabolic scaling in marine teleosts and its implications for aerobic scope

    PubMed Central

    Killen, Shaun S; Costa, Isabel; Brown, Joseph A; Gamperl, A. Kurt

    2006-01-01

    Fish larvae are the world's smallest vertebrates, and their high rates of mortality may be partially owing to a very limited aerobic scope. Unfortunately, however, no complete empirical dataset exists on the relationship between minimal and maximal metabolism (and thus aerobic scope) for any fish species throughout ontogeny, and thus such an association is hard to delineate. We measured standard and maximal metabolism in three marine fish species over their entire life history, and show that while aerobic scope depends greatly on body size and developmental trajectory, it is extremely small during the early life stages (factorial aerobic scope≤1.5). Our findings strongly suggest that limited scope for aerobic activity early in life is likely to constrain physiological function and ultimately impact behaviour and possibly survival. Furthermore, our results have important implications for ecological models that incorporate metabolic scaling, and provide additional evidence against the existence of ‘universal’ scaling exponents. PMID:17164208

  4. The effects of cadence, impact, and step on physiological responses to aerobic dance exercise.

    PubMed

    Darby, L A; Browder, K D; Reeves, B D

    1995-09-01

    The physiological responses to aerobic dance exercise of varied impact (high, low), step (less arm movement vs. more arm movement), and cadence (124 vs. 138 beats.min-1) were investigated. Experienced, female aerobic dancers (N = 16) performed activities that combined the levels of impact and step for 3 trials of 8-min each. Dependent variables included heart rate, percentage of maximal heart rate, oxygen consumption, percentage of maximal oxygen consumption, and respiratory exchange ratio. Repeated measures analyses of variance indicated a significant Impact x Step interaction whereby oxygen consumption was greater for the high impact-less arm movement activity (jog), while the low impact-more arm movement activity (power jack) was greater for heart rate. The interaction of aerobic dance characteristics (e.g., impact, arm movement) that may alter physiological responses to aerobic dance exercise should be identified in future aerobic dance routines and studies. PMID:7481084

  5. Aerobic biotransformation of polyfluoroalkyl phosphate esters (PAPs) in soil.

    PubMed

    Liu, Chen; Liu, Jinxia

    2016-05-01

    Microbial transformation of polyfluoroalkyl phosphate esters (PAPs) into perfluorocarboxylic acids (PFCAs) has recently been confirmed to occur in activated sludge and soil. However, there lacks quantitative information about the half-lives of the PAPs and their significance as the precursors to PFCAs. In the present study, the biotransformation of 6:2 and 8:2 diPAP in aerobic soil was investigated in semi-dynamics reactors using improved sample preparation methods. To develop an efficient extraction method for PAPs, six different extraction solvents were compared, and the phenomenon of solvent-enhanced hydrolysis was investigated. It was found that adding acetic acid could enhance the recoveries of the diPAPs and inhibit undesirable hydrolysis during solvent extraction of soil. However 6:2 and 8:2 monoPAPs, which are the first breakdown products from diPAPs, were found to be unstable in the six solvents tested and quickly hydrolyzed to form fluorotelomer alcohols. Therefore reliable measurement of the monoPAPs from a live soil was not achievable. The apparent DT50 values of 6:2 diPAP and 8:2 diPAP biotransformation were estimated to be 12 and > 1000 days, respectively, using a double first-order in parallel model. At the end of incubation of day 112, the major degradation products of 6:2 diPAP were 5:3 fluorotelomer carboxylic acid (5:3 acid, 9.3% by mole), perfluoropentanoic acid (PFPeA, 6.4%) and perfluorohexanoic acid (PFHxA, 6.0%). The primary product of 8:2 diPAP was perfluorooctanoic acid (PFOA, 2.1%). The approximately linear relationship between the half-lives of eleven polyfluoroalkyl and perfluoroalkyl substances (PFASs, including 6:2 and 8:2 diPAPs) that biotransform in aerobic soils and their molecular weights suggested that the molecular weight is a good indicator of the general stability of low-molecular-weight PFAS-based compounds in aerobic soils. PMID:26849529

  6. 210Pb and 210Po, manganese and iron cycling across the O2/H2S interface of a permanently anoxic fjord: Framvaren, Norway

    USGS Publications Warehouse

    Swarzenski, Peter W.; McKee, Brent A.; Sorensen, Kai; Todd, James F.

    1999-01-01

    Vertical profiles of dissolved and particulate 210Po and 210b were measured across the redox transition zone at Station F1 in Framvaren Fjord, Norway. In this fjord, a sharp decrease in pH above the O2/H2S interface facilitates the aerobic dissolution of MnO2. In contrast, Fe(II) concentrations begin to increase only at the O2/H2S interface depth. Activity profiles reveal that dissolved 210Po and 210Pb are sequestered efficiently by particulates in surface waters. As polonium-210 and lead-210 activities descend down into the aerobic manganese reduction (AMR) zone, they are remobilized during the reductive dissolution of the carrier phase oxyhydroxides. Both 210Po and 210Pb are highly enriched at the O2/H2S interface where an active community of microbes, such as anoxygenic phototrophs (e.g., Chromatium, Chlorobium sp.), thrives. The coincident peaks in 210Po, 210Pb and microbial biomass suggest a strong biological influence on the behavior of these radionuclides. There is a strong covariance between the vertical distribution of Mn and Pb, indicating that their redox cycling is closely coupled and is likely microbially mediated.

  7. 210Pb and 210Po, manganese and iron cycling across the O2/H2S interface of a permanently anoxic fjord: Framvaren, Norway

    USGS Publications Warehouse

    Swarzenski, Peter W.; McKee, Brent A.; Sorenson, Kai; Todd, James F.

    1999-01-01

    Vertical profiles of dissolved and particulate 201Po and 210Pb were measured across the redox transition zone at Station F1 in Framvaren Fjord, Norway. In this fjord, a sharp decrease in pH above the O2/H2S interface facilitates the aerobic dissolution of MnO2. In contrast, Fe(II) concentrations begin to increase only at the O2/H2S interface depth. Activity profiles reveal that dissolved 210Po and 210Pb are sequestered efficiently by particulates in surface waters. As polonium-210 and lead-210 activities descend down into the aerobic manganese reduction (AMR) zone, they are remobilized during the reductive dissolution of the carrier phase oxyhydroxides. Both 210Po and 210Pb are highly enriched at the O2/H2S interface where an active community of microbes, such as anoxygenic phototrophs (e.g., Chromatium, Chlorobium sp.), thrives. The coincident peaks in 210Po and 210Pb and microbial biomass suggest a strong biological influence on the behavior of these radionuclides. There is a strong covariance between the vertical distribution of Mn and Pb, indicating that their redox cycling is closely coupled and is likely microbially mediated.

  8. Oxovanadium complex-catalyzed aerobic oxidation of propargylic alcohols.

    PubMed

    Maeda, Yasunari; Kakiuchi, Nobuyuki; Matsumura, Satoshi; Nishimura, Takahiro; Kawamura, Takashi; Uemura, Sakae

    2002-09-20

    A catalytic system consisting of vanadium oxyacetylacetonate [VO(acac)(2)] and 3 A molecular sieves (MS3A) in acetonitrile works effectively for the aerobic oxidation of propargylic alcohols [R(1)CH(OH)Ctbd1;CR(2)] to the corresponding carbonyl compounds under an atmospheric pressure of molecular oxygen. Although the reactivity of alpha-acetylenic alkanols (R(1) = alkyl) is lower compared to that of the alcohols of R(1) = aryl, alkenyl, and alkynyl, the use of VO(hfac)(2) as a catalyst and the addition of hexafluoroacetylacetone improve the product yield in these cases. A catalytic cycle involving a vanadium(V) alcoholate species and beta-hydrogen elimination from it has been proposed for this oxidation. PMID:12227802

  9. Phosphatase activity of aerobic and facultative anaerobic bacteria.

    PubMed

    Pácová, Z; Kocur, M

    1978-10-01

    1115 strains of aerobic and facultatively anaerobic bacteria were tested for phosphatase activity by a conventional plate method and a microtest. The microtest was devised to allow results to be read after 4 h cultivation. Phosphatase activity was found in wide range of species and strains. Besides staphylococci, where the test for phosphatase is successfully used, it may be applied as one of the valuable tests for the differentiation of the following species: Bacillus cereus, B. licheniformis, Aeromonas spp., Vibrio parahaemolyticus, Actinobacillus spp., Pasteurella spp., Xanthomonas spp., Flavobacterium spp., Alteromonas putrefaciens, Pseudomonas maltophilia, Ps. cepacia, and some other species of Pseudomonas. The species which gave uniformly negative phosphatase reaction were as follows: Staph. saprophyticus, Acinetobacter calcoaceticus, Alcaligenes faecalis, and Bordetella bronchiseptica. PMID:216188

  10. Denitrification kinetics in anoxic/aerobic activated sludge systems

    SciTech Connect

    Horne, G.M.

    1998-12-11

    Nitrogen removal needs at municipal wastewater treatment plants (WWTPs) have increased due to greater concerns about eutrophication and increased interest in reuse of treated municipal effluents. Biological processes are the most cost-effective method for nitrogen removal. Biological nitrogen removal is accomplished in two distinctly different processes by the conversion of nitrogen in the wastewater from organic nitrogen and ammonia to nitrate, followed by reduction of the nitrate to nitrogen gas. Nitrate production occurs in an aerobic activated sludge treatment zone during a process called nitrification. The nitrate is then converted through a series of intermediate steps to nitrogen gas in an anoxic zone (an anaerobic condition with nitrate present) during a process called denitrification, effectively removing the nitrogen from the wastewater. Many different WWTP designs have been developed to incorporate these two conditions for nitrogen removal.

  11. Enzymes and genes involved in aerobic alkane degradation

    PubMed Central

    Wang, Wanpeng; Shao, Zongze

    2013-01-01

    Alkanes are major constituents of crude oil. They are also present at low concentrations in diverse non-contaminated because many living organisms produce them as chemo-attractants or as protecting agents against water loss. Alkane degradation is a widespread phenomenon in nature. The numerous microorganisms, both prokaryotic and eukaryotic, capable of utilizing alkanes as a carbon and energy source, have been isolated and characterized. This review summarizes the current knowledge of how bacteria metabolize alkanes aerobically, with a particular emphasis on the oxidation of long-chain alkanes, including factors that are responsible for chemotaxis to alkanes, transport across cell membrane of alkanes, the regulation of alkane degradation gene and initial oxidation. PMID:23755043

  12. Aerobic sludge granulation at high temperatures for domestic wastewater treatment.

    PubMed

    Ab Halim, Mohd Hakim; Nor Anuar, Aznah; Azmi, Siti Izaidah; Jamal, Nur Syahida Abdul; Wahab, Norhaliza Abdul; Ujang, Zaini; Shraim, Amjad; Bob, Mustafa M

    2015-06-01

    With inoculum sludge from a conventional activated sludge wastewater treatment plant, three sequencing batch reactors (SBRs) fed with synthetic wastewater were operated at different high temperatures (30, 40 and 50±1°C) to study the formation of aerobic granular sludge (AGS) for simultaneous organics and nutrients removal with a complete cycle time of 3h. The AGS were successfully cultivated with influent loading rate of 1.6CODg(Ld)(-1). The COD/N ratio of the influent wastewater was 8. The results revealed that granules developed at 50°C have the highest average diameter, (3.36mm) with 98.17%, 94.45% and 72.46% removal efficiency observed in the system for COD, ammonia and phosphate, respectively. This study also demonstrated the capabilities of AGS formation at high temperatures which is suitable to be applied for hot climate conditions. PMID:25851807

  13. Aerobic sulfur-oxidizing bacteria: Environmental selection and diversification

    NASA Technical Reports Server (NTRS)

    Caldwell, D.

    1985-01-01

    Sulfur-oxidizing bacteria oxidize reduced inorganic compounds to sulfuric acid. Lithotrophic sulfur oxidizer use the energy obtained from oxidation for microbial growth. Heterotrophic sulfur oxidizers obtain energy from the oxidation of organic compounds. In sulfur-oxidizing mixotrophs energy are derived either from the oxidation of inorganic or organic compounds. Sulfur-oxidizing bacteria are usually located within the sulfide/oxygen interfaces of springs, sediments, soil microenvironments, and the hypolimnion. Colonization of the interface is necessary since sulfide auto-oxidizes and because both oxygen and sulfide are needed for growth. The environmental stresses associated with the colonization of these interfaces resulted in the evolution of morphologically diverse and unique aerobic sulfur oxidizers.

  14. Motion sickness susceptibility and aerobic fitness: a longitudinal study.

    PubMed

    Cheung, B S; Money, K E; Jacobs, I

    1990-03-01

    A longitudinal study evaluated the susceptibility to motion sickness in initially unfit subjects before and after an endurance training program. Motion stimulation was provided by the Precision Angular Mover, in which the subject was tumbled head over heels about an Earth-horizontal axis at 20 cycles per minute in darkness. Maximal aerobic power and the blood lactate response to submaximal exercise were evaluated with cycle ergometry. The training program caused significant improvements in VO2max and endurance capacity, and a significant decrease in percent body fat. There was a significant (p less than 0.0125) increase in motion sickness susceptibility after the physical training, suggesting that increased physical fitness caused increased susceptibility to motion sickness in some individuals. PMID:2156490

  15. Poplar lignin decomposition by gram-negative aerobic bacteria

    SciTech Connect

    Odier, E.; Janin, G.; Monties, B.

    1981-02-01

    Eleven gram-negative aerobic bacteria (Pseudomonadaceae and Neisseriaceae) out of 122 soil isolates were selected for their ability to assimilate poplar dioxane lignin without a cosubstrate. Dioxane lignin and milled wood lignin degradation rates ranged between 20 and 40% of initial content after 7 days in mineral medium, as determined by a loss of absorbance at 280 nm; 10 strains could degrade in situ lignin, as evidenced by the decrease of the acetyl bromide lignin content of microtome wood sections. No degradation of wood polysaccharides was detected. Lignin biodegradation by Pseudomonas 106 was confirmed by 14CO2 release from labeled poplar wood, although in lower yields compared with results obtained through chemical analysis based on acetyl bromide residual lignin determination. (Refs. 31).

  16. Enhancing aerobic granulation for biological nutrient removal from domestic wastewater.

    PubMed

    Coma, M; Verawaty, M; Pijuan, M; Yuan, Z; Bond, P L

    2012-01-01

    This study focuses on the enhancement of aerobic granulation and biological nutrient removal maintenance treating domestic wastewater. Two sequencing batch reactors (SBRs) were inoculated with either only floccular sludge (100%-floc SBR) or supplemented with 10% crushed granules (90%-floc SBR). Granules developed in both reactors. The 100%-floc SBR achieved 75% of nitrogen and 93% of phosphorus removal at the end of the performance, but some floccular sludge remained in the system. The 90%-floc SBR became fully granulated and finished with 84% and 99% of nitrogen and phosphorus removal, respectively. Regarding biological phosphorus removal, nitrite was identified as an inhibitor of the process. Nitrite levels lower than 5 mg N-NO2-L(-1) were used for anoxic phosphate uptake while higher concentrations inhibited the process. PMID:22050837

  17. Aerobic exercise improves gastrointestinal motility in psychiatric inpatients

    PubMed Central

    Kim, Yeon Soo; Song, Bong Kil; Oh, Ji Sun; Woo, Seung Seok

    2014-01-01

    AIM: To evaluate the benefit of aerobic exercise on colonic transit time (CTT) for psychiatric inpatients in a closed ward. METHODS: Sixty consecutive adult inpatients of the Somang Hospital Psychiatry Unit (Eumsung-gun, South Korea), without CTT-related diseases or drug therapies, were recruited for study from March to June of 2012. Upon enrollment, the patients were randomly assigned to partake in a 12-wk instructor-led group aerobic exercise program (exercise group; n = 30) or to maintain their ordinary daily activities (control group; n = 30). The exercise program was structured as 10 min warm-up (stretching), 40 min exercise, and 10 min cool-down (stretching) for three days each week. The exercise sessions consisted of walking only in week one and aerobics from weeks two to 12, with increasing intensity (50% heart rate reserve (HRR) for weeks one to four, 60% HRR for weeks five to eight, and 70% HRR for weeks nine to 12). CTT was measured before (baseline) and after (week 12) the exercise program, in duplicate (on days four and seven), using abdominal radiography and the multiple radio-opaque marker technique. Changes in the exercising patients’ CTT and weight-, cardiovascular- and fitness-related parameters were statistically assessed. RESULTS: The study dropout rate was 30.0%, with 23 patients in the exercise group and 19 patients in the control group completing the study. At week 12, the exercise group showed decreases in body weight (mean ± SE) baseline: 69.4 ± 2.8 vs study-end: 67.6 ± 2.7; P < 0.635) and body mass index (BMI) (25.2 ± 1.1 vs 24.9 ± 0.8; P < 0.810), but the extent of change was not significantly different from that experienced by the control group (body weight: 68.8 ± 4.0 vs 68.8 ± 3.9; BMI: 24.3 ± 1.1 vs 24.4 ± 1.2). However, the exercise group showed significant improvements in leg muscle strength (baseline: 41.7 ± 4.3 vs study-end: 64.1 ± 5.0; P < 0.001), cardio-respiratory endurance (120.5 ± 4.5 vs 105.4 ± 2.8; P < 0

  18. Targeting aerobic glycolysis: 3-bromopyruvate as a promising anticancer drug.

    PubMed

    Cardaci, Simone; Desideri, Enrico; Ciriolo, Maria Rosa

    2012-02-01

    The Warburg effect refers to the phenomenon whereby cancer cells avidly take up glucose and produce lactic acid under aerobic conditions. Although the molecular mechanisms underlying tumor reliance on glycolysis remains not completely clear, its inhibition opens feasible therapeutic windows for cancer treatment. Indeed, several small molecules have emerged by combinatorial studies exhibiting promising anticancer activity both in vitro and in vivo, as a single agent or in combination with other therapeutic modalities. Therefore, besides reviewing the alterations of glycolysis that occur with malignant transformation, this manuscript aims at recapitulating the most effective pharmacological therapeutics of its targeting. In particular, we describe the principal mechanisms of action and the main targets of 3-bromopyruvate, an alkylating agent with impressive antitumor effects in several models of animal tumors. Moreover, we discuss the chemo-potentiating strategies that would make unparalleled the putative therapeutic efficacy of its use in clinical settings. PMID:22328057

  19. Aerobic glycolysis: a novel target in kidney cancer.

    PubMed

    Shuch, Brian; Linehan, W Marston; Srinivasan, Ramaprasad

    2013-06-01

    Renal cell carcinoma (RCC) is a heterogenous group of cancers that arise from the nephron. While there are distinct histologic subtypes associated with common genetic alterations, most forms of RCC are linked by a common pathway of dysregulated metabolism. Reliance on aerobic glycolysis, a feature of cancer first hypothesized by Warburg, is a common feature in sporadic and hereditary forms of kidney cancer. Two hereditary forms of RCC, succinate dehydrogenase (SDH) and hereditary leiomyomatosis and RCC (HLRCC), are characterized by mutations in Krebs cycle enzymes, rendering them dependent on glycolysis for energy requirements. The reliance on these pathways may make them vulnerable to novel metabolic strategies, including inhibition of glycolysis, glucose uptake and macromolecule biosynthesis. PMID:23773105

  20. Aerobic Linear Allylic C-H Amination: Overcoming Benzoquinone Inhibition.

    PubMed

    Pattillo, Christopher C; Strambeanu, Iulia I; Calleja, Pilar; Vermeulen, Nicolaas A; Mizuno, Tomokazu; White, M Christina

    2016-02-01

    An efficient aerobic linear allylic C-H amination reaction is reported under palladium(II)/bis-sulfoxide/Brønsted base catalysis. The reaction operates under preparative, operationally simple conditions (1 equiv of olefin, 1 atm O2 or air) with reduced Pd(II)/bis-sulfoxide catalyst loadings while providing higher turnovers and product yields than systems employing stoichiometric benzoquinone (BQ) as the terminal oxidant. Pd(II)/BQ π-acidic interactions have been invoked in various catalytic processes and are often considered beneficial in promoting reductive functionalizations. When such electrophilic activation for functionalization is not needed, however, BQ at high concentrations may compete with crucial ligand (bis-sulfoxide) binding and inhibit catalysis. Kinetic studies reveal an inverse relationship between the reaction rate and the concentration of BQ, suggesting that BQ is acting as a ligand for Pd(II) which results in an inhibitory effect on catalysis. PMID:26730458

  1. Aerobic Fitness Does Not Contribute to Prediction of Orthostatic Intolerance

    NASA Technical Reports Server (NTRS)

    Convertino, Victor A.; Sather, Tom M.; Goldwater, Danielle J.; Alford, William R.

    1986-01-01

    Several investigations have suggested that orthostatic tolerance may be inversely related to aerobic fitness (VO (sub 2max)). To test this hypothesis, 18 males (age 29 to 51 yr) underwent both treadmill VO(sub 2max) determination and graded lower body negative pressures (LBNP) exposure to tolerance. VO(2max) was measured during the last minute of a Bruce treadmill protocol. LBNP was terminated based on pre-syncopal symptoms and LBNP tolerance (peak LBNP) was expressed as the cumulative product of LBNP and time (torr-min). Changes in heart rate, stroke volume cardiac output, blood pressure and impedance rheographic indices of mid-thigh-leg initial accumulation were measured at rest and during the final minute of LBNP. For all 18 subjects, mean (plus or minus SE) fluid accumulation index and leg venous compliance index at peak LBNP were 139 plus or minus 3.9 plus or minus 0.4 ml-torr-min(exp -2) x 10(exp 3), respectively. Pearson product-moment correlations and step-wise linear regression were used to investigate relationships with peak LBNP. Variables associated with endurance training, such as VO(sub 2max) and percent body fat were not found to correlate significantly (P is less than 0.05) with peak LBNP and did not add sufficiently to the prediction of peak LBNP to be included in the step-wise regression model. The step-wise regression model included only fluid accumulation index leg venous compliance index, and blood volume and resulted in a squared multiple correlation coefficient of 0.978. These data do not support the hypothesis that orthostatic tolerance as measured by LBNP is lower in individuals with high aerobic fitness.

  2. Parallel pathways of ethoxylated alcohol biodegradation under aerobic conditions.

    PubMed

    Zembrzuska, Joanna; Budnik, Irena; Lukaszewski, Zenon

    2016-07-01

    Non-ionic surfactants (NS) are a major component of the surfactant flux discharged into surface water, and alcohol ethoxylates (AE) are the major component of this flux. Therefore, biodegradation pathways of AE deserve more thorough investigation. The aim of this work was to investigate the stages of biodegradation of homogeneous oxyethylated dodecanol C12E9 having 9 oxyethylene subunits, under aerobic conditions. Enterobacter strain Z3 bacteria were chosen as biodegrading organisms under conditions with C12E9 as the sole source of organic carbon. Bacterial consortia of river water were used in a parallel test as an inoculum for comparison. The LC-MS technique was used to identify the products of biodegradation. Liquid-liquid extraction with ethyl acetate was selected for the isolation of C12E9 and metabolites from the biodegradation broth. The LC-MS/MS technique operating in the multiple reaction monitoring (MRM) mode was used for quantitative determination of C12E9, C12E8, C12E7 and C12E6. Apart from the substrate, the homologues C12E8, C12E7 and C12E6, being metabolites of C12E9 biodegradation by shortening of the oxyethylene chain, as well as intermediate metabolites having a carboxyl end group in the oxyethylene chain (C12E8COOH, C12E7COOH, C12E6COOH and C12E5COOH), were identified. Poly(ethylene glycols) (E) having 9, 8 and 7 oxyethylene subunits were also identified, indicating parallel central fission of C12E9 and its metabolites. Similar results were obtained with river water as inoculum. It is concluded that AE, under aerobic conditions, are biodegraded via two parallel pathways: by central fission with the formation of PEG, and by Ω-oxidation of the oxyethylene chain with the formation of carboxylated AE and subsequent shortening of the oxyethylene chain by a single unit. PMID:27037882

  3. Anaerobic/aerobic treatment of selected azo dyes in wastewater

    SciTech Connect

    Seshadri, S.; Bishop, P.L. . Dept. of Civil and Environmental Engineering); Agha, A.M. . Faculty of Civil Engineering)

    1994-01-01

    Azo dyes represent the largest class of dyes in use today. Current environmental concern with these dyes revolves around the potential carcinogenic health risk presented by these dyes or their intermediate biodegradation products when exposed to microflora in the human digestive tract. These dyes may build up in the environment, since many wastewater treatment plants allow these dyes to pass through the system virtually untreated. The initial step in the degradation of these dyes is the cleavage of the Azo bond. This cleavage is often impossible under aerobic conditions, but has been readily demonstrated under anaerobic conditions. The focus of the study was to determine the feasibility of using an anaerobic fluidized-bed reactor to accomplish this cleavage. The effects of typical process variables such as hydraulic retention time (HRT), influent dye concentration levels, and degree of bed fluidization on removal efficiencies were also studied. The four dyes selected for this study were Acid-Orange 7, Acid-Orange 8, Acid-Orange 10, and Acid-Red 14. The effectiveness of using a bench-scale-activated sludge reactor as a sequenced second stage was also examined. Results indicate that nearly complete cleavage of the Azo bond is easily accomplished for each of the four dyes under hydraulic retention times of either 12 or 24 h. Initial results indicate, though, that aromatic amine by-products remain. The sequenced second stage was able to remove the remaining Chemical Oxygen Demand (COD) load to acceptable levels. Work is presently underway to determine the face of the anaerobic by-products in the aerobic second stage.

  4. Cerebral Regulation in Different Maximal Aerobic Exercise Modes.

    PubMed

    Pires, Flávio O; Dos Anjos, Carlos A S; Covolan, Roberto J M; Pinheiro, Fabiano A; St Clair Gibson, Alan; Noakes, Timothy D; Magalhães, Fernando H; Ugrinowitsch, Carlos

    2016-01-01

    We investigated cerebral responses, simultaneously with peripheral and ratings of perceived exertion (RPE) responses, during different VO2MAX-matched aerobic exercise modes. Nine cyclists (VO2MAX of 57.5 ± 6.2 ml·kg(-1)·min(-1)) performed a maximal, controlled-pace incremental test (MIT) and a self-paced 4 km time trial (TT4km). Measures of cerebral (COX) and muscular (MOX) oxygenation were assessed throughout the exercises by changes in oxy- (O2Hb) and deoxy-hemoglobin (HHb) concentrations over the prefrontal cortex (PFC) and vastus lateralis (VL) muscle, respectively. Primary motor cortex (PMC) electroencephalography (EEG), VL, and rectus femoris EMG were also assessed throughout the trials, together with power output and cardiopulmonary responses. The RPE was obtained at regular intervals. Similar motor output (EMG and power output) occurred from 70% of the duration in MIT and TT4km, despite the greater motor output, muscle deoxygenation (↓ MOX) and cardiopulmonary responses in TT4km before that point. Regarding cerebral responses, there was a lower COX (↓ O2Hb concentrations in PFC) at 20, 30, 40, 50 and 60%, but greater at 100% of the TT4km duration when compared to MIT. The alpha wave EEG in PMC remained constant throughout the exercise modes, with greater values in TT4km. The RPE was maximal at the endpoint in both exercises, but it increased slower in TT4km than in MIT. Results showed that similar motor output and effort tolerance were attained at the closing stages of different VO2MAX-matched aerobic exercises, although the different disturbance until that point. Regardless of different COX responses during most of the exercises duration, activation in PMC was preserved throughout the exercises, suggesting that these responses may be part of a centrally-coordinated exercise regulation. PMID:27458381

  5. Novel aerobic tetracycline resistance gene that chemically modifies tetracycline.

    PubMed Central

    Speer, B S; Salyers, A A

    1989-01-01

    A tetracycline resistance gene that was found originally on the Bacteroides plasmid pBF4 confers resistance on Escherichia coli but only when cells are growing aerobically. When E. coli EM24 carrying this aerobic tetracycline resistance (*Tcr) gene is grown in medium containing tetracycline, the resulting spent medium is no longer toxic to tetracycline-sensitive (Tcs) E. coli EM24 (B.S. Speer and A.A. Salyers, J. Bacteriol. 170: 1423-1429, 1988). To determine whether the *Tcr gene product modified tetracycline, we characterized the material resulting from incubation of E. coli (*Tcr) with tetracycline. When [7-3H(N)]tetracycline was added to cultures of E. coli (*Tcr), at least 90% of the label was recovered in the extracellular fluid. Therefore, tetracycline was not being sequestered by the cells. The labeled material behaved similarly to tetracycline with respect to solubility in various organic solvents. However, the UV-visible light spectrum had a single peak at 258 nm, whereas the tetracycline spectrum had a peak at 364 nm. The labeled material also had a faster migration rate than did tetracycline on thin-layer plates in a solvent system of butanol-methanol-10% citric acid (4:1:2, vol/vol/vol) and was separable from tetracycline by reverse-phase high-pressure liquid chromatography, using an acetronitrile-0.1% trifluoroacetic acid solvent system. These results demonstrate that the *Tcr gene product chemically modifies tetracycline. The *Tcr gene is the first example of a chemically modifying tetracycline resistance mechanism. PMID:2644186

  6. Cerebral Regulation in Different Maximal Aerobic Exercise Modes

    PubMed Central

    Pires, Flávio O.; dos Anjos, Carlos A. S.; Covolan, Roberto J. M.; Pinheiro, Fabiano A.; St Clair Gibson, Alan; Noakes, Timothy D.; Magalhães, Fernando H.; Ugrinowitsch, Carlos

    2016-01-01

    We investigated cerebral responses, simultaneously with peripheral and ratings of perceived exertion (RPE) responses, during different VO2MAX-matched aerobic exercise modes. Nine cyclists (VO2MAX of 57.5 ± 6.2 ml·kg−1·min−1) performed a maximal, controlled-pace incremental test (MIT) and a self-paced 4 km time trial (TT4km). Measures of cerebral (COX) and muscular (MOX) oxygenation were assessed throughout the exercises by changes in oxy- (O2Hb) and deoxy-hemoglobin (HHb) concentrations over the prefrontal cortex (PFC) and vastus lateralis (VL) muscle, respectively. Primary motor cortex (PMC) electroencephalography (EEG), VL, and rectus femoris EMG were also assessed throughout the trials, together with power output and cardiopulmonary responses. The RPE was obtained at regular intervals. Similar motor output (EMG and power output) occurred from 70% of the duration in MIT and TT4km, despite the greater motor output, muscle deoxygenation (↓ MOX) and cardiopulmonary responses in TT4km before that point. Regarding cerebral responses, there was a lower COX (↓ O2Hb concentrations in PFC) at 20, 30, 40, 50 and 60%, but greater at 100% of the TT4km duration when compared to MIT. The alpha wave EEG in PMC remained constant throughout the exercise modes, with greater values in TT4km. The RPE was maximal at the endpoint in both exercises, but it increased slower in TT4km than in MIT. Results showed that similar motor output and effort tolerance were attained at the closing stages of different VO2MAX-matched aerobic exercises, although the different disturbance until that point. Regardless of different COX responses during most of the exercises duration, activation in PMC was preserved throughout the exercises, suggesting that these responses may be part of a centrally-coordinated exercise regulation. PMID:27458381

  7. Aerobic biodegradation of organic compounds in hydraulic fracturing fluids.

    PubMed

    Kekacs, Daniel; Drollette, Brian D; Brooker, Michael; Plata, Desiree L; Mouser, Paula J

    2015-07-01

    Little is known of the attenuation of chemical mixtures created for hydraulic fracturing within the natural environment. A synthetic hydraulic fracturing fluid was developed from disclosed industry formulas and produced for laboratory experiments using commercial additives in use by Marcellus shale field crews. The experiments employed an internationally accepted standard method (OECD 301A) to evaluate aerobic biodegradation potential of the fluid mixture by monitoring the removal of dissolved organic carbon (DOC) from an aqueous solution by activated sludge and lake water microbial consortia for two substrate concentrations and four salinities. Microbial degradation removed from 57 % to more than 90 % of added DOC within 6.5 days, with higher removal efficiency at more dilute concentrations and little difference in overall removal extent between sludge and lake microbe treatments. The alcohols isopropanol and octanol were degraded to levels below detection limits while the solvent acetone accumulated in biological treatments through time. Salinity concentrations of 40 g/L or more completely inhibited degradation during the first 6.5 days of incubation with the synthetic hydraulic fracturing fluid even though communities were pre-acclimated to salt. Initially diverse microbial communities became dominated by 16S rRNA sequences affiliated with Pseudomonas and other Pseudomonadaceae after incubation with the synthetic fracturing fluid, taxa which may be involved in acetone production. These data expand our understanding of constraints on the biodegradation potential of organic compounds in hydraulic fracturing fluids under aerobic conditions in the event that they are accidentally released to surface waters and shallow soils. PMID:26037076

  8. Aerobic power and peak power of elite America's Cup sailors.

    PubMed

    Neville, Vernon; Pain, Matthew T G; Folland, Jonathan P

    2009-05-01

    Big-boat yacht racing is one of the only able bodied sporting activities where standing arm-cranking ('grinding') is the primary physical activity. However, the physiological capabilities of elite sailors for standing arm-cranking have been largely unreported. The purpose of the study was to assess aerobic parameters, VO(2peak) and onset of blood lactate (OBLA), and anaerobic performance, torque-crank velocity and power-crank velocity relationships and therefore peak power (P (max)) and optimum crank-velocity (omega(opt)), of America's Cup sailors during standing arm-cranking. Thirty-three elite professional sailors performed a step test to exhaustion, and a subset of ten grinders performed maximal 7 s isokinetic sprints at different crank velocities, using a standing arm-crank ergometer. VO(2peak) was 4.7 +/- 0.5 L/min (range 3.6-5.5 L/min) at a power output of 332 +/- 44 W (range 235-425 W). OBLA occurred at a power output of 202 +/- 31 W (61% of W(max)) and VO(2) of 3.3 +/- 0.4 L/min (71% of VO(2peak)). The torque-crank velocity relationship was linear for all participants (r = 0.9 +/- 0.1). P (max) was 1,420 +/- 37 W (range 1,192-1,617 W), and omega(opt) was 125 +/- 6 rpm. These data are among the highest upper-body anaerobic and aerobic power values reported. The unique nature of these athletes, with their high fat-free mass and specific selection and training for standing arm cranking, likely accounts for the high values. The influence of crank velocity on peak power implies that power production during on-board 'grinding' may be optimised through the use of appropriate gear-ratios and the development of efficient gear change mechanisms. PMID:19234715

  9. Aerobic glycolysis tunes YAP/TAZ transcriptional activity

    PubMed Central

    Enzo, Elena; Santinon, Giulia; Pocaterra, Arianna; Aragona, Mariaceleste; Bresolin, Silvia; Forcato, Mattia; Grifoni, Daniela; Pession, Annalisa; Zanconato, Francesca; Guzzo, Giulia; Bicciato, Silvio; Dupont, Sirio

    2015-01-01

    Increased glucose metabolism and reprogramming toward aerobic glycolysis are a hallmark of cancer cells, meeting their metabolic needs for sustained cell proliferation. Metabolic reprogramming is usually considered as a downstream consequence of tumor development and oncogene activation; growing evidence indicates, however, that metabolism on its turn can support oncogenic signaling to foster tumor malignancy. Here, we explored how glucose metabolism regulates gene transcription and found an unexpected link with YAP/TAZ, key transcription factors regulating organ growth, tumor cell proliferation and aggressiveness. When cells actively incorporate glucose and route it through glycolysis, YAP/TAZ are fully active; when glucose metabolism is blocked, or glycolysis is reduced, YAP/TAZ transcriptional activity is decreased. Accordingly, glycolysis is required to sustain YAP/TAZ pro-tumorigenic functions, and YAP/TAZ are required for the full deployment of glucose growth-promoting activity. Mechanistically we found that phosphofructokinase (PFK1), the enzyme regulating the first committed step of glycolysis, binds the YAP/TAZ transcriptional cofactors TEADs and promotes their functional and biochemical cooperation with YAP/TAZ. Strikingly, this regulation is conserved in Drosophila, where phosphofructokinase is required for tissue overgrowth promoted by Yki, the fly homologue of YAP. Moreover, gene expression regulated by glucose metabolism in breast cancer cells is strongly associated in a large dataset of primary human mammary tumors with YAP/TAZ activation and with the progression toward more advanced and malignant stages. These findings suggest that aerobic glycolysis endows cancer cells with particular metabolic properties and at the same time sustains transcription factors with potent pro-tumorigenic activities such as YAP/TAZ. PMID:25796446

  10. Mechanism of aerobic biological destabilisation of wool scour effluent emulsions.

    PubMed

    Poole, Andrew J; Cord-Ruwisch, Ralf; William Jones, F

    2005-07-01

    Wool scouring effluent is a highly polluted industrial wastewater in which the main pollutant, wool wax, is held in a stable oil-in-water emulsion by non-ionic detergent. The use of microbial action to cause emulsion destabilisation has been proposed as a new treatment strategy for this effluent stream. This strategy aims at improving aerobic treatment performance by physically removing the high-COD, slowly bio-degradable wool wax from the system without bio-degradation. The mechanism by which an aerobic-mixed culture destabilises the wool scouring effluent emulsion was investigated. Our results show that destabilisation is due to partial bio-degradation of both the scouring detergent and the wool wax. Cleavage of the wool wax esters was the first stage in wax degradation, when 40-50% of wax was de-emulsified. Over the same period, detergent degradation was low, at 7-21%. With further incubation, detergent degradation increased, aiding further breakdown of the emulsion. The degradation of the detergent, a nonylphenol ethoxylate, resulted in both a reduction in molar concentration (of up to 82%) and a shortening of the ethoxylate chain length. The latter reduced the hydrophile-lipophile balance (HLB) from 12 to approximately 7, thereby reducing the ability of the residual detergent to stabilise the emulsion. Analysis of the emulsified and de-emulsified wax fractions could not identify a group of compounds that were preferentially de-emulsified based on molecular weight or polarity. These findings will assist in using a de-emulsification strategy in both existing and new treatment systems in order to save on aeration costs and treatment times for biological treatment of this highly polluted wastewater. PMID:15979119

  11. Optimizing aerobic conversion of glycerol to 3-hydroxypropionaldehyde

    SciTech Connect

    Slininger, P.J.; Bothast, R.J.

    1985-12-01

    Chemical oxidation of 3-hydroxypropionaldehyde (3-HPA) leads to acrylic acid, an industrially important polymerizable monomer currently derived from petroleum. As the availability of petroleum declines, 3-HPA may become attractive as a product to be obtained through fermentation of glycerol, a renewable resource. When cells of Klebsiella pneumoniae NRRL B-199 (ATCC 8724) were grown aerobically on a rich glycerol medium and then suspended in buffer supplemented with semicarbazide and glycerol, aerobic conversion of glycerol to 3-hydroxypropionaldehyde (3-HPA) ensued. Depending on conditions, 0.38 to 0.67 g of 3-HPA were formed per gram of glycerol consumed. This means that up to 83.8% of the carbon invested as glycerol could potentially be recovered as the target product, 3-HPA. Production of 3-HPA was sensitive to the age of cells harvested for resuspension and was nonexistent if cells were cultivated on glucose instead of glycerol as the sole carbon source. Compared with 24- and 72-h cells, 48-h cells produced 3-HPA at the highest rate and with the greatest yield. The cell biomass concentration present during the fermentation was never particularly critical to the 3-HPA yield, but initial fermentation rates and 3-HPA accumulation displayed a linear dependence on biomass concentration that faded when biomass exceeded 3 g/liter. Fermentation performance was a function of temperature, and an optimum initial specific 3-HPA productivity occurred at 32/sup 0/C, although the overall 3-HPA yield increased continuously within the 25 to 37/sup 0/C range studied. The pH optimum based on fermentation rate was different from that based on overall yield; 8 versus 7, respectively. Initial glycerol concentrations in the 20 to 50 g/liter range optimized initial 3-HPA productivity and yield.

  12. [Formation Mechanism of Aerobic Granular Sludge and Removal Efficiencies in Integrated ABR-CSTR Reactor].

    PubMed

    Wu, Kai-cheng; Wu, Peng; Xu, Yue-zhong; Li, Yue-han; Shen, Yao-liang

    2015-08-01

    Anaerobic Baffled Reactor (ABR) was altered to make an integrated anaerobic-aerobic reactor. The research investigated the mechanism of aerobic sludge granulation, under the condition of continuous-flow. The last two compartments of the ABR were altered into aeration tank and sedimentation tank respectively with seeded sludge of anaerobic granular sludge in anaerobic zone and conventional activated sludge in aerobic zone. The HRT was gradually decreased in sedimentation tank from 2.0 h to 0.75 h and organic loading rate was increased from 1.5 kg x (M3 x d)(-1) to 2.0 kg x (M3 x d)(-1) while the C/N of 2 was controlled in aerobic zone. When the system operated for 110 days, the mature granular sludge in aerobic zone were characterized by compact structure, excellent sedimentation performance (average sedimentation rate was 20.8 m x h(-1)) and slight yellow color. The system performed well in nitrogen and phosphorus removal under the conditions of setting time of 0.75 h and organic loading rate of 2.0 kg (m3 x d)(-1) in aerobic zone, the removal efficiencies of COD, NH4+ -N, TP and TN were 90%, 80%, 65% and 45%, respectively. The results showed that the increasing selection pressure and the high organic loading rate were the main propulsions of the aerobic sludge granulation. PMID:26592026

  13. Performance of sequential anaerobic/aerobic digestion applied to municipal sewage sludge.

    PubMed

    Tomei, M Concetta; Rita, Sara; Mininni, Giuseppe

    2011-07-01

    A promising alternative to conventional single phase processing, the use of sequential anaerobic-aerobic digestion, was extensively investigated on municipal sewage sludge from a full scale wastewater treatment plant. The objective of the work was to evaluate sequential digestion performance by testing the characteristics of the digested sludge in terms of volatile solids (VS), Chemical Oxygen Demand (COD) and nitrogen reduction, biogas production, dewaterability and the content of proteins and polysaccharides. VS removal efficiencies of 32% in the anaerobic phase and 17% in the aerobic one were obtained, and similar COD removal efficiencies (29% anaerobic and 21% aerobic) were also observed. The aerobic stage was also efficient in nitrogen removal providing a decrease of the nitrogen content in the supernatant attributable to nitrification and simultaneous denitrification. Moreover, in the aerobic phase an additional marked removal of proteins and polysaccharides produced in the anaerobic phase was achieved. The sludge dewaterability was evaluated by determining the Optimal Polymer Dose (OPD) and the Capillary Suction Time (CST) and a significant positive effect due to the aerobic stage was observed. Biogas production was close to the upper limit of the range of values reported in the literature in spite of the low anaerobic sludge retention time of 15 days. From a preliminary analysis it was found that the energy demand of the aerobic phase was significantly lower than the recovered energy in the anaerobic phase and the associated additional cost was negligible in comparison to the saving derived from the reduced amount of sludge to be disposed. PMID:21477916

  14. Influence of an aniline supplement on the stability of aerobic granular sludge.

    PubMed

    Dai, Yajie; Jiang, Yixin; Su, Haijia

    2015-10-01

    In order to evaluate the stability of aerobic granules in a toxic environment, this study discussed the influence of an aniline supplement on the properties and microbial community of aerobic granules. In the early stages of sequencing batch reactor (SBR) operation, an aniline supplement slightly affected the properties of the aerobic granules (strength, growth rate, SVI and so on). This effect was thereafter removed because of a change in the microbial community and the structure of aerobic granules: with the present of aniline, microbes with biodegradation ability appeared and gathered in the aerobic granules and the aerobic granules densified and settled faster as their SVI decreased to 35 mL/g and settling velocity increased to 41.56 m/h. When a synthetic waste water containing acetate as carbon source was used as influent, aniline (10-500 mg/L) could be degraded in 6 h, at a rate as high as 37.5 mg aniline/(L·h), with a removal rate in excess of 90%, while the effluent COD fell below 100 mg/L from the initial about 2000 mg/L. The aerobic granules cultured by acetate were compact, stable and resistant to aniline. PMID:26233584

  15. Assessment of Aerobic and Respiratory Growth in the Lactobacillus casei Group

    PubMed Central

    Zotta, Teresa; Ricciardi, Annamaria; Ianniello, Rocco G.; Parente, Eugenio; Reale, Anna; Rossi, Franca; Iacumin, Lucilla; Comi, Giuseppe; Coppola, Raffaele

    2014-01-01

    One hundred eighty four strains belonging to the species Lactobacillus casei, L. paracasei and L. rhamnosus were screened for their ability to grow under aerobic conditions, in media containing heme and menaquinone and/or compounds generating reactive oxygen species (ROS), in order to identify respiratory and oxygen-tolerant phenotypes. Most strains were able to cope with aerobic conditions and for many strains aerobic growth and heme or heme/menaquinone supplementation increased biomass production compared to anaerobic cultivation. Only four L. casei strains showed a catalase-like activity under anaerobic, aerobic and respiratory conditions and were able to survive in presence of H2O2 (1 mM). Almost all L. casei and L. paracasei strains tolerated menadione (0.2 mM) and most tolerated pyrogallol (50 mM), while L. rhamnosus was usually resistant only to the latter compound. This is the first study in which an extensive screening of oxygen and oxidative stress tolerance of members of the L. casei group has been carried out. Results allowed the selection of strains showing the typical traits of aerobic and respiratory metabolism (increased pH and biomass under aerobic or respiratory conditions) and unique oxidative stress response properties. Aerobic growth and respiration may confer technological and physiological advantages in the L. casei group and oxygen-tolerant phenotypes could be exploited in several food industry applications. PMID:24918811

  16. Promoting Motor Cortical Plasticity with Acute Aerobic Exercise: A Role for Cerebellar Circuits

    PubMed Central

    Mang, Cameron S.; Brown, Katlyn E.; Neva, Jason L.; Snow, Nicholas J.; Campbell, Kristin L.; Boyd, Lara A.

    2016-01-01

    Acute aerobic exercise facilitated long-term potentiation-like plasticity in the human primary motor cortex (M1). Here, we investigated the effect of acute aerobic exercise on cerebellar circuits, and their potential contribution to altered M1 plasticity in healthy individuals (age: 24.8 ± 4.1 years). In Experiment   1, acute aerobic exercise reduced cerebellar inhibition (CBI) (n = 10, p = 0.01), elicited by dual-coil paired-pulse transcranial magnetic stimulation. In Experiment   2, we evaluated the facilitatory effects of aerobic exercise on responses to paired associative stimulation, delivered with a 25 ms (PAS25) or 21 ms (PAS21) interstimulus interval (n = 16 per group). Increased M1 excitability evoked by PAS25, but not PAS21, relies on trans-cerebellar sensory pathways. The magnitude of the aerobic exercise effect on PAS response was not significantly different between PAS protocols (interaction effect: p = 0.30); however, planned comparisons indicated that, relative to a period of rest, acute aerobic exercise enhanced the excitatory response to PAS25 (p = 0.02), but not PAS21 (p = 0.30). Thus, the results of these planned comparisons indirectly provide modest evidence that modulation of cerebellar circuits may contribute to exercise-induced increases in M1 plasticity. The findings have implications for developing aerobic exercise strategies to “prime” M1 plasticity for enhanced motor skill learning in applied settings. PMID:27127659

  17. Aerobic fitness predicts relational memory but not item memory performance in healthy young adults.

    PubMed

    Baym, Carol L; Khan, Naiman A; Pence, Ari; Raine, Lauren B; Hillman, Charles H; Cohen, Neal J

    2014-11-01

    Health factors such as an active lifestyle and aerobic fitness have long been linked to decreased risk of cardiovascular disease, stroke, and other adverse health outcomes. Only more recently have researchers begun to investigate the relationship between aerobic fitness and memory function. Based on recent findings in behavioral and cognitive neuroscience showing that the hippocampus might be especially sensitive to the effects of exercise and fitness, the current study assessed hippocampal-dependent relational memory and non-hippocampal-dependent item memory in young adults across a range of aerobic fitness levels. Aerobic fitness was assessed using a graded exercise test to measure oxygen consumption during maximal exercise (VO2max), and relational and item memory were assessed using behavioral and eye movement measures. Behavioral results indicated that aerobic fitness was positively correlated with relational memory performance but not item memory performance, suggesting that the beneficial effects of aerobic fitness selectively affect hippocampal function and not that of the surrounding medial temporal lobe cortex. Eye movement results further supported the specificity of this fitness effect to hippocampal function, in that aerobic fitness predicted disproportionate preferential viewing of previously studied relational associations but not of previously viewed items. Potential mechanisms underlying this pattern of results, including neurogenesis, are discussed. PMID:24893739

  18. Setting times of Resilon and other sealers in aerobic and anaerobic environments.

    PubMed

    Nielsen, Benjamin A; Beeler, William J; Vy, Christina; Baumgartner, J Craig

    2006-02-01

    Eleven sealers, including Resilon sealer, were mixed according to manufacturer's instructions. Setting times were determined in both aerobic and anaerobic environments. Two samples of each sealer were mixed and placed in the following conditions: (a) uncovered in an aerobic incubator; (b) covered with a glass cover-slip in the aerobic incubator; (c) covered with phosphate buffered saline in an aerobic incubator; (d) uncovered in an anaerobic incubator; (e) light cured and then placed in the aerobic incubator (Resilon only). All samples were tested for setting times with a Gillmore needle at 15, 30, and 60 minutes, then hourly up to 8 hours, then at 24, 48, and 72 hours, and then weekly up to 3 weeks. Ketac Endo and Kerr Tubliseal, were the fastest sealers to set in aerobic environments. Ketac Endo and Resilon were the fastest sealers to set in anaerobic environments. Roth 801 and Roth 811 were the slowest sealers to set, taking over 3 weeks to set in either anaerobic or aerobic environments. Resilon sealer set in 30 minutes in both anaerobic environments. However, in the presence of air, Resilon took a week to set and when placed in PBS, an uncured layer remained on the surface. PMID:16427461

  19. Kinetics of aerobic cometabolic biodegradation of chlorinated and brominated aliphatic hydrocarbons: A review.

    PubMed

    Jesus, João; Frascari, Dario; Pozdniakova, Tatiana; Danko, Anthony S

    2016-05-15

    This review analyses kinetic studies of aerobic cometabolism (AC) of halogenated aliphatic hydrocarbons (HAHs) from 2001-2015 in order to (i) compare the different kinetic models proposed, (ii) analyse the estimated model parameters with a focus on novel HAHs and the identification of general trends, and (iii) identify further research needs. The results of this analysis show that aerobic cometabolism can degrade a wide range of HAHs, including HAHs that were not previously tested such as chlorinated propanes, highly chlorinated ethanes and brominated methanes and ethanes. The degree of chlorine mineralization was very high for the chlorinated HAHs. Bromine mineralization was not determined for studies with brominated aliphatics. The examined research period led to the identification of novel growth substrates of potentially high interest. Decreasing performance of aerobic cometabolism were found with increasing chlorination, indicating the high potential of aerobic cometabolism in the presence of medium- and low-halogenated HAHs. Further research is needed for the AC of brominated aliphatic hydrocarbons, the potential for biofilm aerobic cometabolism processes, HAH-HAH mutual inhibition and the identification of the enzymes responsible for each aerobic cometabolism process. Lastly, some indications for a possible standardization of future kinetic studies of HAH aerobic cometabolism are provided. PMID:26874310

  20. The influence of aerobic fitness status on ventilatory efficiency in patients with coronary artery disease

    PubMed Central

    Prado, Danilo M L; Rocco, Enéas A; Silva, Alexandre G; Silva, Priscila F; Lazzari, Jaqueline M; Assumpção, Gabriela L; Thies, Sheyla B; Suzaki, Claudia Y; Puig, Raphael S; Furlan, Valter

    2015-01-01

    OBJECTIVE: To test the hypotheses that 1) coronary artery disease patients with lower aerobic fitness exhibit a lower ventilatory efficiency and 2) coronary artery disease patients with lower initial aerobic fitness exhibit greater improvements in ventilatory efficiency with aerobic exercise training. METHOD: A total of 123 patients (61.0±0.7 years) with coronary artery disease were divided according to aerobic fitness status into 3 groups: group 1 (n = 34, peak VO2<17.5 ml/kg/min), group 2 (n = 67, peak VO2>17.5 and <24.5 ml/kg/min) and group 3 (n = 22, peak VO2>24.5 ml/kg/min). All patients performed a cardiorespiratory exercise test on a treadmill. Ventilatory efficiency was determined by the lowest VE/VCO2 ratio observed. The exercise training program comprised moderate-intensity aerobic exercise performed 3 times per week for 3 months. Clinicaltrials.gov: NCT02106533 RESULTS: Before intervention, group 1 exhibited both lower peak VO2 and lower ventilatory efficiency compared with the other 2 groups (p<0.05). After the exercise training program, group 1 exhibited greater improvements in aerobic fitness and ventilatory efficiency compared with the 2 other groups (group 1: ▵ = -2.5±0.5 units; group 2: ▵ = -0.8±0.3 units; and group 3: ▵ = -1.4±0.6 units, respectively; p<0.05). CONCLUSIONS: Coronary artery disease patients with lower aerobic fitness status exhibited lower ventilatory efficiency during a graded exercise test. In addition, after 3 months of aerobic exercise training, only the patients with initially lower levels of aerobic fitness exhibited greater improvements in ventilatory efficiency. PMID:25672429