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1

Comparative Genomics of Green Sulfur Bacteria  

DEFF Research Database (Denmark)

Eleven completely sequenced Chlorobi genomes were compared in oligonucleotide usage, gene contents, and synteny. The green sulfur bacteria (GSB) are equipped with a core genome that sustains their anoxygenic phototrophic lifestyle by photosynthesis, sulfur oxidation, and CO(2) fixation. Whole-genome gene family and single gene sequence comparisons yielded similar phylogenetic trees of the sequenced chromosomes indicating a concerted vertical evolution of large gene sets. Chromosomal synteny of genes is not preserved in the phylum Chlorobi. The accessory genome is characterized by anomalous oligonucleotide usage and endows the strains with individual features for transport, secretion, cell wall, extracellular constituents, and a few elements of the biosynthetic apparatus. Giant genes are a peculiar feature of the genera Chlorobium and Prosthecochloris. The predicted proteins have a huge molecular weight of 10(6), and are probably instrumental for the bacteria to generate their own intimate (micro)environment.

Ussery, David

2010-01-01

2

Mechanisms and Evolution of Oxidative Sulfur Metabolism in Green Sulfur Bacteria  

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Green sulfur bacteria (GSB) constitute a closely related group of photoautotrophic and thiotrophic bacteria with limited phenotypic variation. They typically oxidize sulfide and thiosulfate to sulfate with sulfur globules as an intermediate. Based on genome sequence information from 15 strains, the distribution and phylogeny of enzymes involved in their oxidative sulfur metabolism was investigated. At least one homolog of sulfide:quinone oxidoreductase (SQR) is present in all strains. In all ...

Gregersen, Lea H.; Bryant, Donald A.; Frigaard, Niels-ulrik

2011-01-01

3

Photoreduction and reoxidation of the three iron-sulfur clusters of reaction centers of green sulfur bacteria.  

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Iron-sulfur clusters are the terminal electron acceptors of the photosynthetic reaction centers of green sulfur bacteria and photosystem I. We have studied electron-transfer reactions involving these clusters in the green sulfur bacterium Chlorobium tepidum, using flash-absorption spectroscopic measurements. We show for the first time that three different clusters, named F(X), F(1), and F(2), can be photoreduced at room temperature during a series of consecutive flashes. The rates of electron...

Se?tif, P.; Seo, D.; Sakurai, H.

2001-01-01

4

Sulfur globule oxidation in green sulfur bacteria is dependent on the dissimilatory sulfite reductase system  

DEFF Research Database (Denmark)

Green sulfur bacteria oxidize sulfide and thiosulfate to sulfate with extracellular globules of elemental sulfur as intermediate. Here we investigated which genes are involved in the formation and consumption of these sulfur globules in the green sulfur bacterium Chlorobaculum tepidum. We show that sulfur globule oxidation is strictly dependent on the dissimilatory sulfite reductase (DSR) system. Deletion of dsrM/CT2244 or dsrT/CT2245 or the two dsrCABL clusters (CT0851-CT0854, CT2247-2250) abolished sulfur globule oxidation and prevented formation of sulfate from sulfide, whereas deletion of dsrU/CT2246 had no effect. The DSR system also seems to be involved in formation of thiosulfate, because thiosulfate is released from wild type cells during sulfide oxidation, but not from the dsr mutants. The dsr mutants incapable of complete substrate oxidation oxidized sulfide and thiosulfate about twice as fast as the wild type, while having only slightly lower growth rates (70-80% of wild type). The increased oxidation rates seem to compensate for the incomplete substrate oxidation to satisfy the requirement for reducing equivalents during growth. A mutant in which two sulfide:quinone oxidoreductases (sqrB/CT0117 and sqrD/CT1087) were deleted, exhibited a decreased sulfide oxidation rate (~50% of wild type), yet formation and consumption of sulfur globules were not affected. The observation that mutants lacking the DSR system maintain efficient growth, suggests that the DSR system is dispensable in environments with sufficient sulfide concentrations. Thus, the DSR system in GSB may have been acquired by horizontal gene transfer in a response to a need for improved substrate utilization in sulfide-limiting habitats.

Holkenbrink, Carina; Ocón Barbas, Santiago

2011-01-01

5

Mechanisms and evolution of oxidative sulfur metabolism in green sulfur bacteria  

Directory of Open Access Journals (Sweden)

Full Text Available Green sulfur bacteria (GSB constitute a closely related group of photoautotrophic and thiotrophic bacteria with limited phenotypic variation. They typically oxidize sulfide and thiosulfate to sulfate with sulfur globules as an intermediate. Based on genome sequence information from 15 strains, the distribution and phylogeny of enzymes involved in their oxidative sulfur metabolism was investigated. At least one homolog of sulfide:quinone oxidoreductase (SQR is present in all strains. In all sulfur-oxidizing GSB strains except the earliest diverging Chloroherpeton thalassium, the sulfide oxidation product is further oxidized to sulfite by the dissimilatory sulfite reductase (DSR system. This system consists of components horizontally acquired partly from sulfide-oxidizing and partly from sulfate-reducing bacteria. Depending on the strain, the sulfite is probably oxidized to sulfate by one of two different mechanisms that have different evolutionary origins: adenosine-5’-phosphosulfate reductase (APR or polysulfide reductase-like complex 3 (PSRLC3. Thiosulfate utilization by the SOX system in GSB has apparently been acquired horizontally from proteobacteria. SoxCD does not occur in GSB, and its function in sulfate formation in other bacteria has been replaced by the DSR system in GSB. Sequence analyses suggested that the conserved soxJXYZAKBW gene cluster was horizontally acquired by Chlorobium phaeovibrioides DSM 265 from the Chlorobaculum lineage and that this acquisition was mediated by a mobile genetic element. Thus, the last common ancestor of currently known GSB was probably photoautotrophic, hydrogenotrophic, and contained SQR but not DSR or SOX. In addition, the predominance of the Chlorobium-Chlorobaculum-Prosthecochloris lineage among cultured GSB could be due to the horizontally acquired DSR and SOX systems. Finally, based upon structural, biochemical, and phylogenetic analyses, a uniform nomenclature is suggested for sqr genes in prokaryotes.

Niels-UlrikFrigaard

2011-05-01

6

Chromatic acclimation and population dynamics of green sulfur bacteria grown with spectrally tailored light  

CERN Document Server

Living organisms have to adjust to their surrounding in order to survive in stressful conditions. We study this mechanism in one of most primitive creatures - photosynthetic green sulfur bacteria. These bacteria absorb photons very efficiently using the chlorosome antenna complexes and perform photosynthesis in extreme low-light environments. How the chlorosomes in green sulfur bacteria are acclimated to the stressful light conditions, for instance, if the spectrum of light is not optimal for absorption, is unknown. Studying Chlorobaculum tepidum cultures with far-red to near-infrared light-emitting diodes, we found that these bacteria react to changes in energy flow by regulating the amount of light-absorbing pigments and the size of the chlorosomes. Surprisingly, our results indicate that the bacteria can survive in near-infrared lights capturing low-frequency photons by the intermediate units of the light-harvesting complex. The latter strategy may be used by the species recently found near hydrothermal ve...

Saikin, Semion K; Huh, Joonsuk; Hannout, Moataz; Wang, Yaya; Zare, Farrokh; Aspuru-Guzik, Alan; Tang, Joseph Kuo-Hsiang

2014-01-01

7

Atomistic study of energy funneling in the light-harvesting complex of green sulfur bacteria  

CERN Document Server

Phototrophic organisms such as plants, photosynthetic bacteria and algae use microscopic complexes of pigment molecules to absorb sunlight. Within the light-harvesting complexes, which frequently have multiple functional and structural subunits, the energy is transferred in the form of molecular excitations with very high efficiency. Green sulfur bacteria are considered to be amongst the most efficient light-harvesting organisms. Despite multiple experimental and theoretical studies of these bacteria the physical origin of the efficient and robust energy transfer in their light-harvesting complexes is not well understood. To study excitation dynamics at the systems level we introduce an atomistic model that mimic a complete light-harvesting apparatus of green sulfur bacteria. The model contains about 4000 pigment molecules and comprises a double wall roll for the chlorosome, a baseplate and six Fenna-Matthews-Olson trimer complexes. We show that the fast relaxation within functional subunits combined with the...

Huh, Joonsuk; Brookes, Jennifer C; Valleau, Stéphanie; Fujita, Takatoshi; Aspuru-Guzik, Alán

2013-01-01

8

Carbon Flow of Heliobacteria Is Related More to Clostridia than to the Green Sulfur Bacteria*  

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The recently discovered heliobacteria are the only Gram-positive photosynthetic bacteria that have been cultured. One of the unique features of heliobacteria is that they have properties of both the photosynthetic green sulfur bacteria (containing the type I reaction center) and Clostridia (forming heat-resistant endospores). Most of the previous studies of heliobacteria, which are strict anaerobes and have the simplest known photosynthetic apparatus, have focused on energy and electron trans...

Tang, Kuo-hsiang; Feng, Xueyang; Zhuang, Wei-qin; Alvarez-cohen, Lisa; Blankenship, Robert E.; Tang, Yinjie J.

2010-01-01

9

The green non-sulfur bacteria: a deep branching in the eubacterial line of descent  

Science.gov (United States)

Ribosomal RNA sequence comparisons define a phylogenetic grouping, the green non-sulfur bacteria and relatives (GNS), known to contain the genera Chloroflexus, Herpetosiphon and Thermomicrobium--organisms that have little phenotypic similarity. The unit is phylogenetically deep, but entirely distinct from any other eubacterial division (phylum). It is also relatively ancient--branching from the common eubacterial stem earlier than any other group of eubacteria reported thus far. The group phenotype is predominantly thermophilic, and its thermophilic members, especially Thermomicrobium, are more slowly evolving than Herpetosiphon, a mesophile. The GNS unit appears significantly older than either the green sulfur bacteria or the cyanobacteria--making it likely that organisms such as Chloroflexus, not the cyanobacteria, generated the oldest stromatolites, which formed over three billion years ago.

Oyaizu, H.; Debrunner-Vossbrinck, B.; Mandelco, L.; Studier, J. A.; Woese, C. R.

1987-01-01

10

Specific detection of green sulfur bacteria by in situ hybridization with a fluorescently labeled oligonucleotide probe.  

Science.gov (United States)

An oligodeoxynucleotide probe (GSB-532) specific for green sulfur bacteria was developed. Highly stringent hybridization conditions were established using whole cells of Chlorobium limicola DSM249 immobilized on glass slides. At a formamide concentration of 10%, the optimum specificity was reached at 47 degrees C. When a conventional fixation procedure was used, a conspicuous autofluorescence developed within the cells. This autofluorescence was due to the liberation of bacteriochlorophyll by the detergent Triton X-100 and a subsequent conversion to bacteriophenophytin and related compounds. The signal-to-noise ratio could be increased by a final dehydration of the samples with methanol. Finally, the method was adapted to the hybridization of natural samples collected on polycarbonate membrane filters. In situ hybridization of pure cultures, various enrichments, and natural samples from the chemocline of a freshwater lake confirmed that probe GSB-532 hybridized exclusively to cells of green sulfur bacteria. Our protocol allows the highly specific detection of green sulfur bacteria in water samples and a rapid screening of natural bacterial communities. Employing probe GSB-532, the phylogenetic affiliation of the epibionts in "Chlorochromatium aggregatum" and "Pelochromatium roseum" could be demonstrated for the first time. PMID:10339808

Tuschak, C; Glaeser, J; Overmann, J

1999-03-01

11

Chromatic acclimation and population dynamics of green sulfur bacteria grown with spectrally tailored light  

Science.gov (United States)

Living organisms have to adjust to their surrounding in order to survive in stressful conditions. We study this mechanism in one of most primitive creatures – photosynthetic green sulfur bacteria. These bacteria absorb photons very efficiently using the chlorosome antenna complexes and perform photosynthesis in extreme low-light environments. How the chlorosomes in green sulfur bacteria are acclimated to the stressful light conditions, for instance, if the spectrum of light is not optimal for absorption, is unknown. Studying Chlorobaculum tepidum cultures with far-red to near-infrared light-emitting diodes, we found that these bacteria react to changes in energy flow by regulating the amount of light-absorbing pigments and the size of the chlorosomes. Surprisingly, our results indicate that the bacteria can survive in near-infrared lights capturing low-frequency photons by the intermediate units of the light-harvesting complex. The latter strategy may be used by the species recently found near hydrothermal vents in the Pacific Ocean.

Saikin, Semion K.; Khin, Yadana; Huh, Joonsuk; Hannout, Moataz; Wang, Yaya; Zare, Farrokh; Aspuru-Guzik, Alan; Tang, Joseph Kuo-Hsiang

2014-01-01

12

Gene expression system in green sulfur bacteria by conjugative plasmid transfer.  

Science.gov (United States)

Gene transfer and expression systems in green sulfur bacteria were established by bacterial conjugation with Escherichia coli. Conjugative plasmid transfer from E. coli S17-1 to a thermophilic green sulfur bacterium, Chlorobaculum tepidum (formerly Chlorobium tepidum) WT2321, was executed with RSF1010-derivative broad-host-range plasmids, named pDSK5191 and pDSK5192, that confer erythromycin and streptomycin/spectinomycin resistance, respectively. The transconjugants harboring these plasmids were reproducibly obtained at a frequency of approximately 10(-5) by selection with erythromycin and a combination of streptomycin and spectinomycin, respectively. These plasmids were stably maintained in C. tepidum cells in the presence of these antibiotics. The plasmid transfer to another mesophilic green sulfur bacterium, C. limnaeum (formerly Chlorobium phaeobacteroides) RK-j-1, was also achieved with pDSK5192. The expression plasmid based on pDSK5191 was constructed by incorporating the upstream and downstream regions of the pscAB gene cluster on the C. tepidum genome, since these regions were considered to include a constitutive promoter and a ?-independent terminator, respectively. Growth defections of the ?cycA and ?soxB mutants were completely rescued after introduction of pDSK5191-cycA and -soxB that were designed to express their complementary genes. On the other hand, pDSK5191-6xhis-pscAB, which incorporated the gene cluster of 6xhis-pscA and pscB, produced approximately four times more of the photosynthetic reaction center complex with His-tagged PscA as compared with that expressed in the genome by the conventional natural transformation method. This expression system, based on conjugative plasmid, would be applicable to general molecular biological studies of green sulfur bacteria. PMID:24312414

Azai, Chihiro; Harada, Jiro; Hirozo, Oh-oka

2013-01-01

13

Photoreduction and reoxidation of the three iron-sulfur clusters of reaction centers of green sulfur bacteria.  

Science.gov (United States)

Iron-sulfur clusters are the terminal electron acceptors of the photosynthetic reaction centers of green sulfur bacteria and photosystem I. We have studied electron-transfer reactions involving these clusters in the green sulfur bacterium Chlorobium tepidum, using flash-absorption spectroscopic measurements. We show for the first time that three different clusters, named F(X), F(1), and F(2), can be photoreduced at room temperature during a series of consecutive flashes. The rates of electron escape to exogenous acceptors depend strongly upon the number of reduced clusters. When two or three clusters are reduced, the escape is biphasic, with the fastest phase being 12-14-fold faster than the slowest phase, which is similar to that observed after single reduction. This is explained by assuming that escape involves mostly the second reducible cluster. Evidence is thus provided for a functional asymmetry between the two terminal acceptors F(1) and F(2). From multiple-flash experiments, it was possible to derive the intrinsic recombination rates between P840(+) and reduced iron-sulfur clusters: values of 7, 14, and 59 s(-1) were found after one, two and three electron reduction of the clusters, respectively. The implications of our results for the relative redox potentials of the three clusters are discussed. PMID:11509338

Sétif, P; Seo, D; Sakurai, H

2001-09-01

14

Multiple types of 8-vinyl reductases for (bacterio)chlorophyll biosynthesis occur in many green sulfur bacteria.  

Science.gov (United States)

Two 8-vinyl reductases, BciA and BciB, have been identified in chlorophototrophs. The bciA gene of Chlorobaculum tepidum was replaced with genes similar to bciB from other green sulfur bacteria. Pigment analyses of the complemented strains showed that the bciB homologs encode 8-vinyl reductases similar to those of cyanobacteria. PMID:21764919

Liu, Zhenfeng; Bryant, Donald A

2011-09-01

15

Multiple Types of 8-Vinyl Reductases for (Bacterio)Chlorophyll Biosynthesis Occur in Many Green Sulfur Bacteria ?  

Science.gov (United States)

Two 8-vinyl reductases, BciA and BciB, have been identified in chlorophototrophs. The bciA gene of Chlorobaculum tepidum was replaced with genes similar to bciB from other green sulfur bacteria. Pigment analyses of the complemented strains showed that the bciB homologs encode 8-vinyl reductases similar to those of cyanobacteria.

Liu, Zhenfeng; Bryant, Donald A.

2011-01-01

16

Low-Temperature Fluorescence from Single Chlorosomes, Photosynthetic Antenna Complexes of Green Filamentous and Sulfur Bacteria  

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Fluorescence spectra of single chlorosomes isolated from a green filamentous bacterium (Chloroflexus (Cfl.) aurantiacus) and a green sulfur bacterium (Chlorobium (Cb.) tepidum) were measured by using a confocal laser microscope at 13 K. Chlorosomes were frozen either in a liquid solution (floating chlorosome) or on a quartz plate after being adsorbed (adsorbed chlorosome). Fluorescence peak wavelengths were shorter for the adsorbed single chlorosomes than for the floating ones. Single floatin...

Shibata, Yutaka; Saga, Yoshitaka; Tamiaki, Hitoshi; Itoh, Shigeru

2006-01-01

17

Dominance of green sulfur bacteria in the chemocline of the meromictic Lake Suigetsu, Japan, as revealed by dissimilatory sulfite reductase gene analysis.  

Science.gov (United States)

This study investigated the spatiotemporal abundance and diversity of the ?-subunit of the dissimilatory sulfite reductase gene (dsrA) in the meromictic Lake Suigetsu for assessing the sulfur-oxidizing bacterial community. The density of dsrA in the chemocline reached up to 3.1 × 10(6) copies ml(-1) in summer by means of quantitative real-time PCR and it was generally higher than deeper layers. Most of the dsrA clones sequenced were related to green sulfur bacteria such as Chlorobium phaeovibrioides, C. limicola, and C. luteolum. Below the chemocline of the lake, we also detected other dsrA clones related to the purple sulfur bacterium Halochromatium salexigens and some branching lineages of diverse sequences that were related to chemotrophic sulfur bacterial species such as Magnetospirillum gryphiswaldense, Candidatus Ruthia magnifica, and Candidatus Thiobios zoothamnicoli. The abundance and community compositions of sulfur-oxidizing bacteria changed depending on the water depth and season. This study indicated that the green sulfur bacteria dominated among sulfur-oxidizing bacterial population in the chemocline of Lake Suigetsu and that certain abiotic environmental variables were important factors that determined sulfur bacterial abundance and community structure. PMID:23455488

Mori, Yumi; Kataoka, Takafumi; Okamura, Takahiko; Kondo, Ryuji

2013-05-01

18

Temperature and Carbon Assimilation Regulate the Chlorosome Biogenesis in Green Sulfur Bacteria  

CERN Document Server

Green photosynthetic bacteria adjust the structure and functionality of the chlorosome - the light absorbing antenna complex - in response to environmental stress factors. The chlorosome is a natural self-assembled aggregate of bacteriochlorophyll (BChl) molecules. In this study we report the regulation of the biogenesis of the Chlorobaculum tepidum chlorosome by carbon assimilation in conjunction with temperature changes. Our studies indicate that the carbon source and thermal stress culture of Cba. tepidum grows slower and incorporates less BChl c in the chlorosome. Compared with the chlorosome from other cultural conditions we investigated, the chlorosome from the carbon source and thermal stress culture displays: (a) smaller cross-sectional radius and overall size; (b) simplified BChl c homologues with smaller side chains; (c) blue-shifted Qy absorption maxima and (d) a sigmoid-shaped circular dichroism (CD) spectra. Using a theoretical model we analyze how the observed spectral modifications can be assoc...

Tang, Joseph Kuo-Hsiang; Pingali, Sai Venkatesh; Enriquez, Miriam M; Huh, Joonsuk; Frank, Harry A; Urban, Volker S; Aspuru-Guzik, Alan

2013-01-01

19

Characterization of a plant-like protochlorophyllide a divinyl reductase in green sulfur bacteria.  

Science.gov (United States)

The green sulfur bacterium Chlorobium tepidum synthesizes three types of (bacterio)chlorophyll ((B)Chl): BChl a(P), Chl a(PD), and BChl c(F). During the synthesis of all three molecules, a C-8 vinyl substituent is reduced to an ethyl group, and in the case of BChl c(F), the C-8(2) carbon of this ethyl group is subsequently methylated once or twice by the radical S-adenosylmethionine enzyme BchQ. The C. tepidum genome contains homologs of two genes, bchJ (CT2014) and CT1063, that are highly homologous to genes, bchJ and AT5G18660, and that have been reported to encode C-8 vinyl reductases in Rhodobacter capsulatus and Arabidopsis thaliana, respectively. To determine which gene product actually encodes a C-8 vinyl reductase activity, the bchJ and CT1063 genes were insertionally inactivated in C. tepidum. All three Chls synthesized by the CT1063 mutant of C. tepidum have a C-8 vinyl group. Using NADPH but not NADH as reductant, recombinant BciA reduces the C-8 vinyl group of 3,8-divinyl-protochlorophyllide in vitro. These data demonstrate that CT1063, renamed bciA, encodes a C-8 divinyl reductase in C. tepidum. The bchJ mutant produces detectable amounts of Chl a(PD), BChl a(P), and BChl c(F), all of which have reduced C-8 substituents, but the mutant cells secrete large amounts of 3,8-divinyl-protochlorophyllide a into the growth medium and have a greatly reduced BChl c(F) content. The results suggest that BchJ may play an important role in substrate channeling and/or regulation of Chl biosynthesis but show that it is not a vinyl reductase. Because only some Chl-synthesizing organisms possess homologs of bciA, at least two types of C-8 vinyl reductases must occur. PMID:17148453

Chew, Aline Gomez Maqueo; Bryant, Donald A

2007-02-01

20

Unifying principles in homodimeric type I photosynthetic reaction centers: properties of PscB and the FA, FB and FX iron-sulfur clusters in green sulfur bacteria.  

Science.gov (United States)

The photosynthetic reaction center from the green sulfur bacterium Chlorobium tepidum (CbRC) was solubilized from membranes using Triton X-100 and isolated by sucrose density ultra-centrifugation. The CbRC complexes were subsequently treated with 0.5 M NaCl and ultrafiltered over a 100 kDa cutoff membrane. The resulting CbRC cores did not exhibit the low-temperature EPR resonances from FA- and FB- and were unable to reduce NADP+. SDS-PAGE and mass spectrometric analysis showed that the PscB subunit, which harbors the FA and FB clusters, had become dissociated, and was now present in the filtrate. Attempts to rebind PscB onto CbRC cores were unsuccessful. Mössbauer spectroscopy showed that recombinant PscB contains a heterogeneous mixture of [4Fe-4S]2+,1+ and other types of Fe/S clusters tentatively identified as [2Fe-2S]2+,1+ clusters and rubredoxin-like Fe3+,2+ centers, and that the [4Fe-4S]2+,1+ clusters which were present were degraded at high ionic strength. Quantitative analysis confirmed that the amount of iron and sulfide in the recombinant protein was sub-stoichiometric. A heme-staining assay indicated that cytochrome c551 remained firmly attached to the CbRC cores. Low-temperature EPR spectroscopy of photoaccumulated CbRC complexes and CbRC cores showed resonances between g=5.4 and 4.4 assigned to a S=3/2 ground spin state [4Fe-4S]1+ cluster and at g=1.77 assigned to a S=1/2 ground spin state [4Fe-4S]1+ cluster, both from FX-. These results unify the properties of the acceptor side of the Type I homodimeric reaction centers found in green sulfur bacteria and heliobacteria: in both, the FA and FB iron-sulfur clusters are present on a salt-dissociable subunit, and FX is present as an interpolypeptide [4Fe-4S]2+,1+ cluster with a significant population in a S=3/2 ground spin state. PMID:18835244

Jagannathan, Bharat; Golbeck, John H

2008-12-01

 
 
 
 
21

Composition and optical properties of reaction centre core complexes from the green sulfur bacteria Prosthecochloris aestuarii and Chlorobium tepidum.  

Science.gov (United States)

Photosynthetically active reaction centre core (RCC) complexes were isolated from two species of green sulfur bacteria, Prosthecochloris (Ptc.) aestuarii strain 2K and Chlorobium (Chl.) tepidum, using the same isolation procedure. Both complexes contained the main reaction centre protein PscA and the iron-sulfur protein PscB, but were devoid of Fenna-Matthews-Olson (FMO) protein. The Chl. tepidum RCC preparation contained in addition PscC (cytochrome c). In order to allow accurate determination of the pigment content of the RCC complexes, the extinction coefficients of bacteriochlorophyll (BChl) a in several solvents were redetermined with high precision. They varied between 54.8 mM(-1) cm(-1) for methanol and 97.0 mM(-1) cm(-1) for diethylether in the Q(Y) maximum. Both preparations appeared to contain 16 BChls a of which two are probably the 13(2)-epimers, 4 chlorophylls (Chls) a 670 and 2 carotenoids per RCC. The latter were of at least two different types. Quinones were virtually absent. The absorption spectra were similar for the two species, but not identical. Eight bands were present at 6 K in the BChl a Q(Y) region, with positions varying from 777 to 837 nm. The linear dichroism spectra showed that the orientation of the BChl a Q(Y) transitions is roughly parallel to the membrane plane; most nearly parallel were transitions at 800 and 806 nm. For both species, the circular dichroism spectra were dominated by a strong band at 807-809 nm, indicating strong interactions between at least some of the BChls. The absorption, CD and LD spectra of the four Chls a 670 were virtually identical for both RCC complexes, indicating that their binding sites are highly conserved and that they are an essential part of the RCC complexes, possibly as components of the electron transfer chain. Low temperature absorption spectroscopy indicated that typical FMO-RCC complexes of Ptc. aestuarii and Chl. tepidum contain two FMO trimers per reaction centre. PMID:16228441

Permentier, H P; Schmidt, K A; Kobayashi, M; Akiyama, M; Hager-Braun, C; Neerken, S; Miller, M; Amesz, J

2000-01-01

22

Experimental Study of Interactions between Purple and Green Sulfur Bacteria in Sandy Sediments Exposed to Illumination Deprived of Near-Infrared Wavelengths  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Sedimentary biofilms of the green sulfur bacterium Prosthecochloris aestuarii strain CE 2404, the purple sulfur bacterium Thiocapsa roseopersicina strain 5811, and a mixed culture of both were cultured in fine sand (100- to 300-?m grain size) within counter gradients of oxygen and sulfide. The artificial sediments were exposed to illumination deprived of near-infrared light (NIR) by filtering out the wavelengths longer than 700 nm to simulate the critical light conditions in submerged aquati...

2002-01-01

23

Specific Gene bciD for C7-Methyl Oxidation in Bacteriochlorophyll e Biosynthesis of Brown-Colored Green Sulfur Bacteria  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The gene named bciD, which encodes the enzyme involved in C7-formylation in bacteriochlorophyll e biosynthesis, was found and investigated by insertional inactivation in the brown-colored green sulfur bacterium Chlorobaculum limnaeum (previously called Chlorobium phaeobacteroides). The bciD mutant cells were green in color, and accumulated bacteriochlorophyll c homologs bearing the 7-methyl group, compared to C7-formylated BChl e homologs in the wild type. BChl-c homolog compositions in the m...

Harada, Jiro; Mizoguchi, Tadashi; Satoh, Souichirou; Tsukatani, Yusuke; Yokono, Makio; Noguchi, Masato; Tanaka, Ayumi; Tamiaki, Hitoshi

2013-01-01

24

Long-Term Population Dynamics of Phototrophic Sulfur Bacteria in the Chemocline of Lake Cadagno, Switzerland  

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Population analyses in water samples obtained from the chemocline of crenogenic, meromictic Lake Cadagno, Switzerland, in October for the years 1994 to 2003 were studied using in situ hybridization with specific probes. During this 10-year period, large shifts in abundance between purple and green sulfur bacteria and among different populations were obtained. Purple sulfur bacteria were the numerically most prominent phototrophic sulfur bacteria in samples obtained from 1994 to 2001, when the...

Tonolla, Mauro; Peduzzi, Raffaele; Hahn, Dittmar

2005-01-01

25

Comprehensive detection of phototrophic sulfur bacteria using PCR primers that target reverse dissimilatory sulfite reductase gene.  

Science.gov (United States)

A new set of primers for the detection of phototrophic sulfur bacteria in natural environments is described. The primers target the ?-subunit of the reverse dissimilatory sulfite reductase gene (dsrA). PCR-amplification resulted in products of the expected size from all the phototrophic strains tested, including purple sulfur and green sulfur bacteria. Seventy-nine clones obtained from environmental DNA using the primers were sequenced and all found to be closely related to the dsrA of purple sulfur bacteria and green sulfur bacteria. This newly developed PCR assay targeting dsrA is rapid and simple for the detection of phototrophic sulfur bacteria in situ and superior to the use of culture-dependent techniques. PMID:21576872

Mori, Yumi; Purdy, Kevin J; Oakley, Brian B; Kondo, Ryuji

2010-01-01

26

Energy transfer from carotenoid and FMO-protein in subcellular preparations from green sulfur bacteria. Spectroscopic characterization of an FMO-reaction center core complex at low temperature.  

Science.gov (United States)

The Fenna-Matthews-Olson (FMO)-protein and the FMO-reaction center (RC) core complex from the green sulfur bacterium Chlorobium tepidum were examined at 6 K by absorption and fluorescence spectroscopy. The absorption spectrum of the RC core complex was obtained by a subtraction method and found to have fiye peaks in the QY region, at 797, 808, 818, 834 and 837 nm. The efficiency of energy transfer from carotenoid to bacteriochlorophyll a in the RC core complex was 23% at 6 K, and from the FMO-protein to the core it was 35%. Energy transfer from the FMO-protein to the core complex was also measured in isolated membranes of Prosthecochloris aestuarii from the action spectra of charge separation. Again, a low efficiency of energy transfer was obtained, both at 6 K and at room temperature. PMID:24271823

Francke, C; Otte, S C; Miller, M; Amesz, J; Olson, J M

1996-10-01

27

Experimental study of interactions between purple and green sulfur bacteria in sandy sediments exposed to illumination deprived of near-infrared wavelengths.  

Science.gov (United States)

Sedimentary biofilms of the green sulfur bacterium Prosthecochloris aestuarii strain CE 2404, the purple sulfur bacterium Thiocapsa roseopersicina strain 5811, and a mixed culture of both were cultured in fine sand (100- to 300-microm grain size) within counter gradients of oxygen and sulfide. The artificial sediments were exposed to illumination deprived of near-infrared light (NIR) by filtering out the wavelengths longer than 700 nm to simulate the critical light conditions in submerged aquatic sediments. A 16 h of visible light-8 h of dark regimen was used. We studied the effects of these light conditions on the metabolisms of and interactions between both species by comparing the single species biofilms with the mixed biofilm. The photosynthesis rates of P. aestuarii were shown to be highly limited by the imposed light conditions, because the sulfide photooxidation rates were strongly stimulated when NIR was added. T. roseopersicina performed both aerobic chemosynthesis and photosynthesis, but the photosynthesis rates were low and poorly stimulated by the addition of NIR. This species decreased the penetration depth of oxygen in the sediment by about 1 mm by actively respiring oxygen. This way, the strict anaerobe P. aestuarii was able to grow closer to the surface in the mixed culture. As a result, P. aestuarii benefited from the presence of T. roseopersicina in the mixed culture, which was reflected by an increase in the biomass. In contrast, the density of the latter species was almost completely unaffected by the interaction. Both species coexisted in a layer of the same depth in the mixed culture, and the ecological and evolutionary implications of coexistence are discussed. PMID:12039757

Massé, Astrid; Pringault, Olivier; De Wit, Rutger

2002-06-01

28

Forster energy transfer in chlorosomes of green photosynthetic bacteria  

Science.gov (United States)

Energy transfer properties of whole cells and chlorosome antenna complexes isolated from the green sulfur bacteria Chlorobium limicola (containing bacteriochlorophyll c), Chlorobium vibrioforme (containing bacteriochlorophyll d) and Pelodictyon phaeoclathratiforme (containing bacteriochlorophyll e) were measured. The spectral overlap of the major chlorosome pigment (bacteriochlorophyll c, d or, e) with the bacteriochlorophyll a B795 chlorosome baseplate pigment is greatest for bacteriochlorophyll c and smallest for bacteriochlorophyll e. The absorbance and fluorescence spectra of isolated chlorosomes were measured, fitted to gaussian curves and the overlap factors with B795 calculated. Energy transfer times from the bacteriochlorophyll c, d or e to B795 were measured in whole cells and the results interpreted in terms of the Forster theory of energy transfer.

Causgrove, T. P.; Brune, D. C.; Blankenship, R. E.

1992-01-01

29

Genetic manipulation of carotenoid biosynthesis in the green sulfur bacterium Chlorobium tepidum.  

Science.gov (United States)

The green sulfur bacterium Chlorobium tepidum is a strict anaerobe and an obligate photoautotroph. On the basis of sequence similarity with known enzymes or sequence motifs, nine open reading frames encoding putative enzymes of carotenoid biosynthesis were identified in the genome sequence of C. tepidum, and all nine genes were inactivated. Analysis of the carotenoid composition in the resulting mutants allowed the genes encoding the following six enzymes to be identified: phytoene synthase (crtB/CT1386), phytoene desaturase (crtP/CT0807), zeta-carotene desaturase (crtQ/CT1414), gamma-carotene desaturase (crtU/CT0323), carotenoid 1',2'-hydratase (crtC/CT0301), and carotenoid cis-trans isomerase (crtH/CT0649). Three mutants (CT0180, CT1357, and CT1416 mutants) did not exhibit a discernible phenotype. The carotenoid biosynthetic pathway in C. tepidum is similar to that in cyanobacteria and plants by converting phytoene into lycopene using two plant-like desaturases (CrtP and CrtQ) and a plant-like cis-trans isomerase (CrtH) and thus differs from the pathway known in all other bacteria. In contrast to the situation in cyanobacteria and plants, the construction of a crtB mutant completely lacking carotenoids demonstrates that carotenoids are not essential for photosynthetic growth of green sulfur bacteria. However, the bacteriochlorophyll a contents of mutants lacking colored carotenoids (crtB, crtP, and crtQ mutants) were decreased from that of the wild type, and these mutants exhibited a significant growth rate defect under all light intensities tested. Therefore, colored carotenoids may have both structural and photoprotection roles in green sulfur bacteria. The ability to manipulate the carotenoid composition so dramatically in C. tepidum offers excellent possibilities for studying the roles of carotenoids in the light-harvesting chlorosome antenna and iron-sulfur-type (photosystem I-like) reaction center. The phylogeny of carotenogenic enzymes in green sulfur bacteria and green filamentous bacteria is also discussed. PMID:15292122

Frigaard, Niels-Ulrik; Maresca, Julia A; Yunker, Colleen E; Jones, A Daniel; Bryant, Donald A

2004-08-01

30

Sodium dodecyl sulfate-polyacrylamide gel protein electrophoresis of freshwater photosynthetic sulfur bacteria.  

Science.gov (United States)

Sodium dodecyl sulfate-polyacrylamide gel protein electrophoresis (SDS-PAGE) was carried out using different bacterial strains of the photosynthetic sulfur bacteria Chlorobium, Thiocapsa, Thiocystis, and Chromatium cultured in the laboratory, and the natural blooms in two karstic lakes (Lake Cisó and Lake Vilar, NE Spain) where planktonic photosynthetic bacteria (purple and green sulfur bacteria) massively developed accounting for most of the microbial biomass. Several extraction, solubilization, and electrophoresis methods were tested to develop an optimal protocol for the best resolution of the SDS-PAGE. Protein composition from different water depths and at different times of the year was visualized within a molecular mass range between 100 and 15 kDa yielding up to 20 different protein bands. Protein banding patterns were reproducible and changed in time and with depth in agreement with changes in photosynthetic bacteria composition. When a taxonomically stable community was followed in time, differences were observed in the intensity but not in the composition of the SDS-PAGE banding pattern. Three environmental variables directly related to the activity of sulfur bacteria (light, oxygen, and sulfide concentrations) had a significant effect on protein banding patterns and explained 33% of the variance. Changes in natural protein profiles of the bacterial blooms agreed with changes in species composition and in the in situ metabolic state of the populations. PMID:20524118

Osuna, M Begoña; Casamayor, Emilio O

2011-01-01

31

[Colorless sulfur bacteria Thioploca from different sites in Lake Baikal].  

Science.gov (United States)

The colorless sulfur bacteria Thioploca spp. found in Lake Baikal are probably a marker for the influx of subterranean mineralized fluids. Bacteria act as a biological filter; by consuming sulfide in their metabolism, they detoxicate it and maintain the purity of Lake Baikal's water. The bacteria were investigated by various techniques. According to analysis of the 16S rRNA gene fragment, Thioploca sp. from Frolikha Bay, Baikal belongs to the clade of freshwater species found in Lake Biwa and Lake Constance; it is most closely related to Thioploca ingrica. PMID:19334606

Zemskaia, T I; Chernitsyna, S M; Dul'tseva, N M; Sergeeva, V N; Pogodaeva, T V; Namsaraev, B B

2009-01-01

32

The reductive tricarboxylic acid cycle of carbon dioxide assimilation: initial studies and purification of ATP-citrate lyase from the green sulfur bacterium Chlorobium tepidum.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Carbon dioxide is fixed largely by the reductive tricarboxylic acid (RTCA) cycle in green sulfur bacteria. One of the key enzymes, ATP-citrate lyase, was purified to apparent homogeneity from the moderately thermophilic green sulfur bacterium Chlorobium tepidum. The molecular weight of the native enzyme was about 550,000, and the preponderance of evidence indicated that the protein is composed of identical subunits (Mr of approximately 135,000) which degraded to two major proteins with Mrs of...

Wahlund, T. M.; Tabita, F. R.

1997-01-01

33

Nitrogen fixation by the thermophilic green sulfur bacterium Chlorobium tepidum.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The thermophilic green sulfur bacterium Chlorobium tepidum grew with N2, NH4+, or glutamine as the sole nitrogen source under phototrophic (anaerobic-light) conditions. Growth on N2 required increased buffering capacity to stabilize uncharacterized pH changes that occurred during diazotrophic growth. Increased sulfide levels were stimulatory for growth on N2. Levels of nitrogenase activity (acetylene reduction) in N2-grown C. tepidum cells were very high, among the highest ever reported for a...

Wahlund, T. M.; Madigan, M. T.

1993-01-01

34

Thioploca spp: filamentous sulfur bacteria with nitrate vacuoles  

DEFF Research Database (Denmark)

Thioploca spp. are multicellular, filamentous, colorless sulfur bacteria inhabiting freshwater and marine sediments. They have elemental sulfur inclusions similar to the phylogenetically closely related Beggiatoa, but in contrast to these they live in bundles surrounded by a common sheath. Vast communities of large Thioploca species live along the Pacific coast of South America and in other upwelling areas of high organic matter sedimentation with bottom waters poor in oxygen and rich in nitrate. Each cell of these thioplocas harbors a large liquid vacuole which is used as a storage for nitrate with a concentration of lip to 506 mM. The nitrate is used as an electron acceptor for sulfide oxidation and the bacteria may grow autotrophically or mixotrophically using acetate or other organic molecules as carbon source. The filaments stretch up into the overlying seawater, from which they take up nitrate, and then glide down 5-15 cm deep into the sediment through their sheaths to oxidize sulfide formed by intensive sulfate reduction. New major occurrences have bren found in recent years, both in lakes and in the ocean, and have stimulated the interest in these fascinating bacteria. (C) 1999 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.

Jørgensen, BB; Gallardo, VA

1999-01-01

35

Biosynthesis and Isotopic Composition of Bacteriochlorophyll a and Okenone in Purple Sulfur Bacteria  

Science.gov (United States)

Phototrophic sulfur bacteria play an integral part in the anaerobic cycling of sulfur. Bacteriochloroyphll a (Bchl a) is a well-studied photosynthetic compound required for photosynthesis in the organisms that possess it. The only known fossil of purple sulfur bacteria (PSB) in the geologic record is okenane, believed to be of biologic origin originating from the carotenoid pigment okenone, which has only been documented in eleven species of Chromatiaceae. Organic geochemical studies have identified okenane in preserved organic matter in rocks and ancient sediments and further, okenone production has been observed in modern water columns and sediment surfaces. We have undertaken a comprehensive study on the biosynthesis of bacterial pigments including okenone and C, N, and S isotopic fractionation during various growth modes in controlled laboratory experiments of purple sulfur bacteria. Cultures of Marichromatium purpuratum 1591, M. purpuratum 1711, Thiocapsa marina 5653, and FGL21 (isolated from the chemocline of Fayetteville Green Lake, NY) were grown under autotrophic and photoheterotrophic (e.g. acetate or pyruvate) conditions in batch cultures. Concentrations of okenone and Bchl a were quantified as a function of time and growth by Ultra Performance-Liquid Chromatography-Mass Spectrometry (UP-LC-MS) and spectrophotometry. Overall okenone and Bchl a concentrations reached ?M levels in the cultures. At stationary phase, all four strains achieved concentrations of okenone and Bchl a that were approximately 2.5 fM and 0.2 fM per cell, respectively, with okenone to Bchl a ratios of approximately 12 to 1. Isotope Ratio Mass Spectrometry (IRMS) was performed on bulk cells and compound specific analysis of Bchl a and okenone to better understand the fractionation associated with the production of the compounds.

Smith, D.; Scott, J. H.; Steele, A.; Cody, G. D.; Ohara, S.; Bowden, R.; Fogel, M. L.

2011-12-01

36

Ametryne and Prometryne as Sulfur Sources for Bacteria  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Bacteria were isolated that could utilize quantitatively the s-triazine herbicide prometryne [N,N? -bis(1-methylethyl)-6-(methylthio)-1,3,5-triazine-2,4-diamine] or ametryne [N-ethyl-N?-(1-methylethyl)-6-(methylthio)-1,3,5-triazine- 2,4-diamine], or both, as a sole source of sulfur for growth. The success of enrichments depended on previous exposure of the soil inoculum to s-triazine herbicides. Deaminoethylametryne [4-(1-methylethyl)amino-6-(methylthio)-1,3,5-triazine-2-(1H)-one], methyl...

Cook, Alasdair M.; Hu?tter, Ralf

1982-01-01

37

Characterization of the group 1 and group 2 sigma factors of the green sulfur bacterium Chlorobium tepidum and the green non-sulfur bacterium Chloroflexus aurantiacus.  

Science.gov (United States)

The group 1 and group 2 sigma70-type sigma factors of the green sulfur bacterium Chlorobium tepidum and of the green nonsulfur bacterium Chloroflexus aurantiacus were cloned and characterized. Cb. tepidum was found to contain one sigma70-type sigma factor; the expression of the gene was analyzed by Northern blot hybridization and primer-extension mapping. Cf. aurantiacus has genes encoding four sigma factors of groups 1 and 2. The expression of these genes was examined in cells grown aerobically and anaerobically. The sigC gene was expressed at approximately equal levels under both conditions, resulting in its designation as the group 1 sigma factor of this organism. The only other detectable transcripts arose from the sigB gene, which was expressed at higher levels during aerobic growth. A phylogenetic tree was obtained using the group 1 sigma factors of Cb. tepidum, Cf. aurantiacus, and diverse eubacteria as the molecular marker. The resulting phylogenetic tree shows that Cb. tepidum and Cf. aurantiacus are related to each other and to the cyanobacteria. The relationship of the group 2 sigma factors of Cf. aurantiacus and the cyanobacteria was more specifically examined phylogenetically. The group 2 sigma factors of Cf. aurantiacus probably arose by gene duplication events after the split of the green nonsulfur bacteria from other photosynthetic eubacteria. PMID:9732443

Gruber, T M; Bryant, D A

1998-10-01

38

SoxAX Binding Protein, a Novel Component of the Thiosulfate-Oxidizing Multienzyme System in the Green Sulfur Bacterium Chlorobium tepidum?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

From the photosynthetic green sulfur bacterium Chlorobium tepidum (pro synon. Chlorobaculum tepidum), we have purified three factors indispensable for the thiosulfate-dependent reduction of the small, monoheme cytochrome c554. These are homologues of sulfur-oxidizing (Sox) system factors found in various thiosulfate-oxidizing bacteria. The first factor is SoxYZ that serves as the acceptor for the reaction intermediates. The second factor is monomeric SoxB that is proposed to catalyze the hydr...

Ogawa, Takuro; Furusawa, Toshinari; Nomura, Ryohei; Seo, Daisuke; Hosoya-matsuda, Naomi; Sakurai, Hidehiro; Inoue, Kazuhito

2008-01-01

39

Sulfur bacteria in wastewater stabilization ponds periodically affected by the ‘red-water’ phenomenon:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Several wastewater stabilization ponds (WSP) in Tunisia suffer periodically from the ‘red-water’ phenomenon due to blooming of purple sulfur bacteria, indicating that sulfur cycle is one of the main element cycles in these ponds. In this study, we investigated the microbial diversity of the El Menzeh WSP and focused in particular on the different functional groups of sulfur bacteria. For this purpose, we used denaturing gradient gel electrophoresis of PCR-amplified fragments of the 16S rR...

2012-01-01

40

Sulfur bacteria in wastewater stabilization ponds periodically affected by the ‘red-water’ phenomenon  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Several wastewater stabilization ponds (WSP) in Tunisia suffer periodically from the ‘red-water’ phenomenon due to blooming of purple sulfur bacteria, indicating that sulfur cycle is one of the main element cycles in these ponds. In this study, we investigated the microbial diversity of the El Menzeh WSP and focused in particular on the different functional groups of sulfur bacteria. For this purpose, we used denaturing gradient gel electrophoresis of PCR-amplified fragments of the 16S rR...

2013-01-01

 
 
 
 
41

[Fe]-hydrogenases in green algae: photo-fermentation and hydrogen evolution under sulfur deprivation  

Energy Technology Data Exchange (ETDEWEB)

Recent studies indicate that [Fe]-hydrogenases and H{sub 2} metabolism are widely distributed among green algae. The enzymes are simple structured and catalyze H{sub 2} evolution with similar rates than the more complex [Fe]-hydrogenases from bacteria. Different green algal species developed diverse strategies to survive under sulfur deprivation. Chlamydomonas reinhardtii evolves large quantities of hydrogen gas in the absence of sulfur. In a sealed culture of C. reinhardtii, the photosynthetic O{sub 2} evolution rate drops below the rate of respiratory O{sub 2} consumption due to a reversible inhibition of photosystem II, thus leading to an intracellular anaerobiosis. The algal cells survive under these anaerobic conditions by switching their metabolism to a kind of photo-fermentation. Although possessing a functional [Fe]-hydrogenase gene, the cells of Scenedesmus obliquus produce no significant amounts of H{sub 2} under S-depleted conditions. Biochemical analyses indicate that S. obliquus decreases almost the complete metabolic activities while maintaining a low level of respiratory activity. (author)

Winkler, M.; Hemschemeier, A.; Happe, T. [Botanisches Institut der Universitat Bonn (Germany); Gotor, C. [CSIC y Universidad de Sevilla (Spain). Instituto de Bioquimica Vegetal y Fotosintesis; Melis, A. [University of California, Berkeley, CA (United States). Department of Plant and Microbial Biology

2002-12-01

42

Sulfur Isotope Analysis of Minerals and Fluids in a Natural CO2 Reservoir, Green River, Utah  

Science.gov (United States)

Predicting the security of geological CO2 storage sites requires an understanding of the geochemical behavior of the stored CO2, especially of fluid-rock reactions in reservoirs, caprocks and fault zones. Factors that may influence geochemical behavior include co-injection of sulfur gases along with the CO2, either in acid-gas disposal or as contaminants in CO2 storage sites, and microbial activity, such as bacterial sulfate reduction. The latter may play an important role in buffering the redox chemistry of subsurface fluids, which could affect toxic trace metal mobilization and transport in acidic CO2-rich fluids. These processes involving sulfur are poorly understood. Natural CO2-reservoirs provide natural laboratories, where the flow and reactions of the CO2-charged fluids and the activity of microbial communities are integrated over sufficient time-scales to aid prediction of long-term CO2 storage. This study reports on sulfur isotope analyses of sulfate and sulfide minerals in rock core and in CO2-charged fluids collected from a stacked sequence of natural CO2 reservoirs at Green River, Utah. Scientific drilling adjacent to a CO2-degassing normal fault to a depth of 325m retrieved core and fluid samples from two CO2 reservoirs in the Entrada and Navajo Sandstones and from the intervening Carmel Formation caprock. Fluid samples were collected from CO2-charged springs that discharge through the faults. Sulfur exists as sulfate in the fluids, as sedimentary gypsum beds in the Carmel Formation, as remobilized gypsum veins within a fault damage zone in the Carmel Fm. and in the Entrada Sandstone, and as disseminated pyrite and pyrite-mineralized open fractures throughout the cored interval. We use the stable sulfur (?34S) and oxygen (?18OSO4) isotopes of the sulfate, gypsum, and pyrite to understand the source of sulfur in the reservoir as well as the timing of gypsum vein and pyrite formation. The hydration water of the gypsum is also reported to explore the different timing of gypsum vein formation. Macroscopic and microscopic gradients in the sulfur isotope composition of pyrite throughout the core and at discernible redox-reaction fronts were examined in detail to assess the role of bacteria in mediating sulfate reduction, sulfide mineralization and buffering of groundwater redox chemistry. The CO2 charged fluids and gypsum veins within the Entrada Sandstone have a narrow and very similar range in both ?34SSO4 and ?18OSO4, suggesting that the fluids (9.1-10.7‰) are the most likely source of the sulfate in the veins (11.4-12.8‰) and that the veins formed during recent fluid flow through the Entrada, with sulfate coming from remobilized gypsum beds in the Carmel. The Carmel also contains two isotopically distinct types of gypsum veins: one with ?34SSO4 values similar to the Entrada veins and one with much higher ?34SSO4 values (15.1-16.1‰). The latter are likely primary gypsum, while the former are likely secondary gypsum. Sulfur isotope fractionation between pyrite (-16.5‰ to -35.7‰) at the Carmel-Navajo interface and reservoir fluids (9.1-10.7‰) suggest that sulfur reducing bacteria play a role in producing the deposited sulfide. This data demonstrates active sulfur cycling in CO2 reservoirs with many different sulfur species cycled among various pools creating the wide isotope dispersion we observe.

Chen, F.; Kampman, N.; Bickle, M. J.; Busch, A.; Turchyn, A. V.

2013-12-01

43

Redox regulation of energy transfer efficiency in antennas of green photosynthetic bacteria  

Science.gov (United States)

The efficiency of energy transfer from the peripheral chlorosome antenna structure to the membrane-bound antenna in green sulfur bacteria depends strongly on the redox potential of the medium. The fluorescence spectra and lifetimes indicate that efficient quenching pathways are induced in the chlorosome at high redox potential. The midpoint redox potential for the induction of this effect in isolated chlorosomes from Chlorobium vibrioforme is -146 mV at pH 7 (vs the normal hydrogen electrode), and the observed midpoint potential (n = 1) decreases by 60 mV per pH unit over the pH range 7-10. Extraction of isolated chlorosomes with hexane has little effect on the redox-induced quenching, indicating that the component(s) responsible for this effect are bound and not readily extractable. We have purified and partially characterized the trimeric water-soluble bacteriochlorophyll a-containing protein from the thermophilic green sulfur bacterium Chlorobium tepidum. This protein is located between the chlorosome and the membrane. Fluorescence spectra of the purified protein indicate that it also contains groups that quench excitations at high redox potential. The results indicate that the energy transfer pathway in green sulfur bacteria is regulated by redox potential. This regulation appears to operate in at least two distinct places in the energy transfer pathway, the oligomeric pigments in the interior of the chlorosome and in the bacteriochlorophyll a protein. The regulatory effect may serve to protect the cell against superoxide-induced damage when oxygen is present. By quenching excitations before they reach the reaction center, reduction and subsequent autooxidation of the low potential electron acceptors found in these organisms is avoided.

Blankenship, R. E.; Cheng, P.; Causgrove, T. P.; Brune, D. C.; Wang, J.

1993-01-01

44

Motility patterns of filamentous sulfur bacteria, Beggiatoa spp.  

DEFF Research Database (Denmark)

The large sulfur bacteria, Beggiatoa spp., live on the oxidation of sulfide with oxygen or nitrate, but avoid high concentrations of both sulfide and oxygen. As gliding filaments, they rely on reversals in the gliding direction to find their preferred environment, the oxygenâ??sulfide interface.We observed the chemotactic patterns of single filaments in a transparent agar medium and scored their reversals and the glided distances between reversals. Filaments within the preferred microenvironment glided distances shorter than their own length between reversals that anchored them in their position as a microbial mat. Filaments in the oxic region above the mat or in the sulfidic, anoxic region below the mat glided distances longer than the filament length between reversals. This reversal behavior resulted in a diffusion-like spreading of the filaments. A numerical model of such gliding filaments was constructed based on our observations. The model was applied to virtual filaments in the oxygen- and sulfide-free zone of the sediment, which is a main habitat of Beggiatoa in the natural environment. The model predicts a long residence time of the virtual filament in the suboxic zone and explains why Beggiatoa accumulate high nitrate concentrations in internal vacuoles as an alternative electron acceptor to oxygen.

Dunker, Rita; Røy, Hans

2011-01-01

45

Sulfate- and Sulfur-Reducing Bacteria as Terrestrial Analogs for Microbial Life on Jupiter's Satellite Io  

Science.gov (United States)

Observations from the Voyager and Galileo spacecraft have revealed Jupiter's moon Io to be the most volcanically active body of our Solar System. The Galileo Near Infrared Imaging Spectrometer (NIMS) detected extensive deposits of sulfur compounds, elemental sulfur and SO2 frost on the surface of Io. There are extreme temperature variations on Io's surface, ranging from -130 C to over 2000 C at the Pillan Patera volcanic vent. The active volcanoes, fumaroles, calderas, and lava lakes and vast sulfur deposits on this frozen moon indicate that analogs of sulfur- and sulfate-reducing bacteria might inhabit Io. Hence Io may have great significance to Astrobiology. Earth's life forms that depend on sulfur respiration are members of two domains: Bacteria and Archaea. Two basic links of the biogeochemical sulfur cycle of Earth have been studied: 1) the sulfur oxidizing process (occurring at aerobic conditions) and 2) the process of sulfur-reduction to hydrogen sulfide (anaerobic conditions). Sulfate-reducing bacteria (StRB) and sulfur-reducing bacteria (SrRB) are responsible for anaerobic reducing processes. At the present time the systematics of StRB include over 112 species distributed into 35 genera of Bacteria and Archaea. Moderately thermophilic and mesophilic SrRB belong to the Bacteria. The hyperthermophilic SrRB predominately belong to the domain Archaea and are included in the genera: Pyrodictium, Thermoproteus, Pyrobaculum, Thermophilum, Desulfurococcus, and Thermodiscus. The StRB and SrRB use a wide spectrum of substrates as electron donors for lithotrophic and heterotrophic type nutrition. The electron acceptors for the StRB include: sulfate, thiosulfate, sulfite, sulfur, arsenate, dithionite, tetrathionate, sulfur monoxide, iron, nitrite, selenite, fumarate, oxygen, carbon dioxide, and chlorine-containing phenol compounds. The Sulfate- and Sulfur-reducing bacteria are widely distributed in anaerobic ecosystems, including extreme environments like hot springs, deepsea hydrothermal vents, soda and high salinity lakes, and cryo-environments. Furthermore, the StRB and SrRB have Astrobiological significance as these anaerobic extremophiles may represent the dominant relic life forms that inhabited our planet during the extensive volcanic activity in the Earth's early evolutionary period.

Pikuta, Elena V.; Hoover, Richard B.; Six, N. Frank (Technical Monitor)

2001-01-01

46

Membrane-associated c-type cytochromes from the green sulfur bacterium Chlorobium limicola forma thiosulfatophilum: purification and characterization of cytochrome c553.  

Science.gov (United States)

Tetraheme cytochromes involved in photosynthetic electron transport have previously been described associated with the reaction centers of purple photosynthetic bacteria; however, similar heme proteins have not until now been characterized in the phylogenetically distinct green sulfur bacteria. In this paper we describe the first isolation and characterization of a multitheme, membrane-associated cytochrome from a green sulfur bacterium, Chlorobium limicola forma thiosulfatophilum. We show that this cytochrome contains a single polypeptide of 32 kDa apparent molecular mass on SDS-PAGE and has a characteristic broad alpha-band absorption at 553 nm. By both low-temperature absorption and electron paramagnetic resonance spectroscopy, we demonstrate that there are at least four distinct heme groups. PMID:9048580

Albouy, D; Sturgis, J N; Feiler, U; Nitschke, W; Robert, B

1997-02-18

47

Taurine-Sulfur Assimilation and Taurine-Pyruvate Aminotransferase Activity in Anaerobic Bacteria  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We demonstrated the ability of strictly fermentative, as well as facultatively fermentative, bacteria to assimilate sulfonate sulfur for growth. Taurine (2-aminoethanesulfonate) can be utilized by Clostridium pasteurianum C1 but does not support fermentative growth of two Klebsiella spp. and two different Clostridium spp. However, the latter are able to assimilate the sulfur of a variety of other sulfonates (e.g., cysteate, 3-sulfopyruvate, and 3-sulfolactate) anaerobically. A novel taurine-p...

Chien, C.; Leadbetter, E. R.; Godchaux, W.

1997-01-01

48

Chemolithotrophic Sulfur-Oxidizing Bacteria from the Galapagos Rift Hydrothermal Vents †  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Three distinct physiological types of sulfur-oxidizing bacteria were enriched and isolated from samples collected at several deep-sea hydrothermal vents (2,550 m) of the Galapagos Rift ocean floor spreading center. Twelve strains of the obligately chemolithotrophic genus Thiomicrospira were obtained from venting water and from microbial mats covering surfaces in the immediate vicinity of the vents. From these and other sources two types of obligately heterotrophic sulfur oxidizers were repeat...

Ruby, E. G.; Wirsen, C. O.; Jannasch, H. W.

1981-01-01

49

Proteomic analysis of chlorosome-depleted membranes of the green sulfur bacterium Chlorobium tepidum.  

Science.gov (United States)

Green sulfur bacteria are obligate anaerobic phototrophs, which in addition to outer and plasma membranes contain chlorosomes. The analysis of the membrane proteome of Chlorobium tepidum from chlorosome-depleted membranes is described in this study. The membranes were purified by sucrose density centrifugation and characterized by 1-DE and 2-DE coupled with MS, absorption spectroscopy, and electron microscopy. 1-DE and 2-DE were employed to analyze the membrane proteins and to characterize the capabilities of the methods. Solubilization of the membrane proteins prior to 2-DE was improved by using a series of zwitterionic detergents. Based on the resolved spots after 2-DE, the combination of amidosulfobetaine 14 with Triton X-100 is more efficient than the combination of CHAPS, N-decyl-N,N-dimethyl-3-ammonio-1-propane sulfonate, and Triton X-100. From the application of 1-DE and 2-DE, 167 and 202 unique proteins were identified, respectively, using PMF by MALDI-TOF MS. Both methods resulted in the detection of 291 different proteins of which only 88 were predicted membrane proteins, indicating the limitation of membrane protein detection after separation with electrophoresis methods. In addition, 53 of these proteins were identified as outer membrane proteins. PMID:16294302

Aivaliotis, Michalis; Haase, Winfried; Karas, Michael; Tsiotis, Georgios

2006-01-01

50

Physiology of purple sulfur bacteria forming macroscopic aggregates in Great Sippewissett Salt Marsh, Massachusetts  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Purple bacterial aggregates found in tidal pools of Great Sippewissett Salt Marsh (Falmouth, Cape Cod, MA) were investigated in order to elucidate the ecological significance of cell aggregation. Purple sulfur bacteria were the dominant microorganisms in the aggregates which also contained diatoms and a high number of small rod-shaped bacteria. Urea in concentrations of ? 1 M caused disintegration of the aggregates while proteolytic enzymes, surfactants or chaotropic agents did not...

1993-01-01

51

Modeling the electron transport chain of purple non-sulfur bacteria  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Purple non-sulfur bacteria (Rhodospirillaceae) have been extensively employed for studying principles of photosynthetic and respiratory electron transport phosphorylation and for investigating the regulation of gene expression in response to redox signals. Here, we use mathematical modeling to evaluate the steady-state behavior of the electron transport chain (ETC) in these bacteria under different environmental conditions. Elementary-modes analysis of a stoichiometric ETC model reveals nine ...

Klamt, Steffen; Grammel, Hartmut; Straube, Ronny; Ghosh, Robin; Gilles, Ernst Dieter

2008-01-01

52

Oxygen uncouples light absorption by the chlorosome antenna and photosynthetic electron transfer in the green sulfur bacterium chlorobium tepidum  

Science.gov (United States)

In photosynthetic green sulfur bacteria excitation energy is transferred from large bacteriochlorophyll (BChl) c chlorosome antennas via small BChl a antennas to the reaction centers which then transfer electrons from cytochrome c to low-potential iron-sulfur proteins. Under oxidizing conditions a reversible mechanism is activated in the chlorosomes which quenches excited BChl c. We used flash-induced cytochrome c oxidation to investigate the effect of this quenching on photosynthetic electron transfer in whole cells of Chlorobium tepidum. The extent of cytochrome c photooxidation under aerobic conditions decreased to approx. 3% of that under anaerobic conditions when BChl c was excited under light-limiting conditions. Photooxidation obtained by excitation of BChl a was similar under aerobic and anaerobic conditions. We interpret this drastic decrease in energy transfer from BChl c to the reaction center as a consequence of the quenching mechanism which is activated by O2. This reversible uncoupling of the chlorosome antenna might prevent formation of toxic reactive oxygen species from photosynthetically produced reductants under aerobic conditions. The green filamentous bacterium Chloroflexus aurantiacus also contains chlorosomes but energy transfer from the BChl c and BChl a antennas to the reaction center in this species was not affected by O2. PMID:10393254

Frigaard; Matsuura

1999-06-30

53

Competition for sulfide among colorless and purple sulfur bacteria in cyanobacterial mats.  

Science.gov (United States)

The vertical zonation of light, O2, H2S, pH, and sulfur bacteria was studied in two benthic cyanobacterial mats from hypersaline ponds at Guerrero Negro, Baja California, Mexico. The physical-chemical gradients were analyzed in the upper few mm at depth of the photic zone, colorless sulfur bacteria (Beggiatoa sp.) were the dominant sulfide oxidizing organisms. In a mat, where the O2-H2S interface was close to the photic zone, but yet received no significant visible light, purple sulfur bacteria (Chromatium sp.) were the dominant sulfide oxidizers. Analysis of the spectral light distribution here showed that the penetration of only 1% of the incident near-IR light (800-900 nm) into the sulfide zone was sufficient for the mass development of Chromatium in a narrow band of 300 micromoles thickness. The balance between O2 and light penetration down into the sulfide zone thus determined in micro-scale which type of sulfur bacteria became dominant. PMID:11542103

Jorgensen, B B; Des Marais, D J

1986-01-01

54

Competition for sulfide among colorless and purple sulfur bacteria in cyanobacterial mats  

Science.gov (United States)

The vertical zonation of light, O2, H2S, pH, and sulfur bacteria was studied in two benthic cyanobacterial mats from hypersaline ponds at Guerrero Negro, Baja California, Mexico. The physical-chemical gradients were analyzed in the upper few mm at < or = 100 micrometers spatial resolution by microelectrodes and by a fiber optic microprobe. In mats, where oxygen produced by photosynthesis diffused far below the depth of the photic zone, colorless sulfur bacteria (Beggiatoa sp.) were the dominant sulfide oxidizing organisms. In a mat, where the O2-H2S interface was close to the photic zone, but yet received no significant visible light, purple sulfur bacteria (Chromatium sp.) were the dominant sulfide oxidizers. Analysis of the spectral light distribution here showed that the penetration of only 1% of the incident near-IR light (800-900 nm) into the sulfide zone was sufficient for the mass development of Chromatium in a narrow band of 300 micromoles thickness. The balance between O2 and light penetration down into the sulfide zone thus determined in micro-scale which type of sulfur bacteria became dominant.

Jorgensen, B. B.; Des Marais, D. J.

1986-01-01

55

Sulfur oxidation in mutants of the photosynthetic green sulfur bacterium Chlorobium tepidum devoid of cytochrome c-554 and SoxB.  

Science.gov (United States)

A mutant devoid of cytochrome c-554 (CT0075) in Chlorobium tepidum (syn. Chlorobaculum tepidum) exhibited a decreased growth rate but normal growth yield when compared to the wild type. From quantitative determinations of sulfur compounds in media, the mutant was found to oxidize thiosulfate more slowly than the wild type but completely to sulfate as the wild type. This indicates that cytochrome c-554 would increase the rate of thiosulfate oxidation by serving as an efficient electron carrier but is not indispensable for thiosulfate oxidation itself. On the other hand, mutants in which a portion of the soxB gene (CT1021) was replaced with the aacC1 cassette did not grow at all in a medium containing only thiosulfate as an electron source. They exhibited partial growth yields in media containing only sulfide when compared to the wild type. This indicates that SoxB is not only essential for thiosulfate oxidation but also responsible for sulfide oxidation. An alternative electron carrier or electron transfer path would thus be operating between the Sox system and the reaction center in the mutant devoid of cytochrome c-554. Cytochrome c-554 might function in any other pathway(s) as well as the thiosulfate oxidation one, since even green sulfur bacteria that cannot oxidize thiosulfate contain a cycA gene encoding this electron carrier. PMID:19421892

Azai, Chihiro; Tsukatani, Yusuke; Harada, Jiro; Oh-oka, Hirozo

2009-05-01

56

Lamellar organization of pigments in chlorosomes, the light harvesting complexes of green photosynthetic bacteria.  

Science.gov (United States)

Chlorosomes of green photosynthetic bacteria constitute the most efficient light harvesting complexes found in nature. In addition, the chlorosome is the only known photosynthetic system where the majority of pigments (BChl) is not organized in pigment-protein complexes but instead is assembled into aggregates. Because of the unusual organization, the chlorosome structure has not been resolved and only models, in which BChl pigments were organized into large rods, were proposed on the basis of freeze-fracture electron microscopy and spectroscopic constraints. We have obtained the first high-resolution images of chlorosomes from the green sulfur bacterium Chlorobium tepidum by cryoelectron microscopy. Cryoelectron microscopy images revealed dense striations approximately 20 A apart. X-ray scattering from chlorosomes exhibited a feature with the same approximately 20 A spacing. No evidence for the rod models was obtained. The observed spacing and tilt-series cryoelectron microscopy projections are compatible with a lamellar model, in which BChl molecules aggregate into semicrystalline lateral arrays. The diffraction data further indicate that arrays are built from BChl dimers. The arrays form undulating lamellae, which, in turn, are held together by interdigitated esterifying alcohol tails, carotenoids, and lipids. The lamellar model is consistent with earlier spectroscopic data and provides insight into chlorosome self-assembly. PMID:15298919

Psencík, J; Ikonen, T P; Laurinmäki, P; Merckel, M C; Butcher, S J; Serimaa, R E; Tuma, R

2004-08-01

57

Succession of Sulfur-Oxidizing Bacteria in the Microbial Community on Corroding Concrete in Sewer Systems† ?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Microbially induced concrete corrosion (MICC) in sewer systems has been a serious problem for a long time. A better understanding of the succession of microbial community members responsible for the production of sulfuric acid is essential for the efficient control of MICC. In this study, the succession of sulfur-oxidizing bacteria (SOB) in the bacterial community on corroding concrete in a sewer system in situ was investigated over 1 year by culture-independent 16S rRNA gene-based molecular ...

Okabe, Satoshi; Odagiri, Mitsunori; Ito, Tsukasa; Satoh, Hisashi

2007-01-01

58

Phylogenetic Evidence for the Existence of Novel Thermophilic Bacteria in Hot Spring Sulfur-Turf Microbial Mats in Japan  

Digital Repository Infrastructure Vision for European Research (DRIVER)

So-called sulfur-turf microbial mats, which are macroscopic white filaments or bundles consisting of large sausage-shaped bacteria and elemental sulfur particles, occur in sulfide-containing hot springs in Japan. However, no thermophiles from sulfur-turf mats have yet been isolated as cultivable strains. This study was undertaken to determine the phylogenetic positions of the sausage-shaped bacteria in sulfur-turf mats by direct cloning and sequencing of 16S rRNA genes amplified from the bulk...

Yamamoto, Hiroyuki; Hiraishi, Akira; Kato, Kenji; Chiura, Hiroshi X.; Maki, Yonosuke; Shimizu, Akira

1998-01-01

59

Leaching of marine manganese nodules by acidophilic bacteria growing on elemental sulfur  

Science.gov (United States)

This article describes the bioleaching of manganese nodules by thermophilic and mesophilic sulfuroxidizing bacteria, in which oxidized sulfur compounds are biologically produced from elemental sulfur added to liquid medium and are simultaneously used to leach nodules. The thermophile Acidianus brierleyi solubilized the manganese nodules faster at 65 °C than did the mesophiles Thiobacillus ferrooxidans and Thiobacillus thiooxidans at 30 °C. Leaching experiments with A. brierleyi growing on elemental sulfur were used to optimize various process parameters, such as medium pH, initial sulfur-liquid loading ratio, and initial cell concentration. The observed dependencies of the leaching rates at a pH optimum on the initial amounts of elemental sulfur and A. brierleyi cells were qualitatively consistent with model simulations for microbial sulfur oxidation. Under the conditions determined as optimum, the leaching of nodule particles (-330+500 mesh) by A. brierleyi yielded 100 pct extraction of both copper and zinc within 4 days and high extractions of nickel (85 pct), cobalt (70 pct), and manganese (55 pct) for 10 days. However, the iron leaching was practically negligible.

Konishi, Yasuhiro; Asai, Satoru; Sawada, Yuichi

1997-02-01

60

Improved hydrogen photoproduction from photosynthetic bacteria and green algae  

Energy Technology Data Exchange (ETDEWEB)

Photosynthetic bacteria evolve hydrogen at much higher rates than do other classes of photosynthetic microorganisms. In addition, they tolerate harsh environments, grow rapidly, and utilize both visible and near infrared light in photosynthesis. They do not split water, but this does not necessarily eliminate their potential use in future applied systems. They are easily manipulated genetically, and thus might be modified to metabolize common biomass waste materials in place of expensive defined organic substrates. Furthermore, the potential for increasing hydrogen photoproduction via genetic techniques is promising. Strains that partially degrade cellulose, have high photoproduction rates, or contain very large amounts of the enzymes associated with hydrogen metabolism have been isolated. Green algae also produce hydrogen but are capable of using water as a substrate. For example, C. reinhardi can evolve hydrogen and oxygen at a molar ratio approaching 2:1. Based upon effect of dichlorophenyl dimethylurea (a specific inhibitor of photosystem II, PSII) on hydrogen photoproduction in the wild type strain and upon results obtained with PSII mutants, one can demonstrate that water is the major source of electrons for hydrogen production. The potential efficiency of in vivo coupling between hydrogenase and the photosynthetic electron transport system is high. Up to 76% of the reductants generated by the electron transport system can be channeled directly to the enzyme for in vivo hydrogen production. Rates exceeding 170 ..mu..moles of H/sub 2/ mg Chl/sup -1/ hr/sup -1/ have been observed.

Weaver, P.F.; Lien, S.; Seibert, M.

1979-01-01

 
 
 
 
61

Application of bacteria involved in the biological sulfur cycle for paper mill effluent purification  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In anaerobic wastewater treatment, the occurrence of biological sulfate reduction results in the formation of unwanted hydrogen sulfide, which is odorous, corrosive and toxic. In this paper, the role and application of bacteria in anaerobic and aerobic sulfur transformations are described and exemplified for the treatment of a paper mill wastewater. The sulfate containing wastewater first passes an anaerobic UASB reactor for bulk COD removal which is accompanied by the formation of biogas and...

2009-01-01

62

Analysis of Subfossil Molecular Remains of Purple Sulfur Bacteria in a Lake Sediment  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Molecular remains of purple sulfur bacteria (Chromatiaceae) were detected in Holocene sediment layers of a meromictic salt lake (Mahoney Lake, British Columbia, Canada). The carotenoid okenone and bacteriophaeophytin a were present in sediments up to 11,000 years old. Okenone is specific for only a few species of Chromatiaceae, including Amoebobacter purpureus, which presently predominates in the chemocline bacterial community of the lake. With a primer set specific for Chromatiaceae in combi...

Coolen, Marco J. L.; Overmann, Jo?rg

1998-01-01

63

Community Structure of Filamentous, Sheath-Building Sulfur Bacteria, Thioploca spp., off the Coast of Chile  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The filamentous sulfur bacteria Thioploca spp. produce dense bacterial mats in the shelf area off the coast of Chile and Peru. The mat consists of common sheaths, shared by many filaments, that reach 5 to 10 cm down into the sediment. The structure of the Thioploca communities off the Bay of Concepcion was investigated with respect to biomass, species distribution, and three-dimensional orientation of the sheaths. Thioploca sheaths and filaments were found across the whole shelf area within t...

Schulz, H. N.; Jorgensen, B. B.; Fossing, H. A.; Ramsing, N. B.

1996-01-01

64

Insights into the genome of large sulfur bacteria revealed by analysis of single filaments  

DEFF Research Database (Denmark)

Marine sediments are frequently covered by mats of the filamentous Beggiatoa and other large nitrate-storing bacteria that oxidize hydrogen sulfide using either oxygen or nitrate, which they store in intracellular vacuoles. Despite their conspicuous metabolic properties and their biogeochemical importance, little is known about their genetic repertoire because of the lack of pure cultures. Here, we present a unique approach to access the genome of single filaments of Beggiatoa by combining whole genome amplification, pyrosequencing, and optical genome mapping. Sequence assemblies were incomplete and yielded average contig sizes of approximately 1 kb. Pathways for sulfur oxidation, nitrate and oxygen respiration, and CO2 fixation confirm the chemolithoautotrophic physiology of Beggiatoa. In addition, Beggiatoa potentially utilize inorganic sulfur compounds and dimethyl sulfoxide as electron acceptors. We propose a mechanism of vacuolar nitrate accumulation that is linked to proton translocation by vacuolar-type ATPases. Comparative genomics indicates substantial horizontal gene transfer of storage, metabolic, and gliding capabilities between Beggiatoa and cyanobacteria. These capabilities enable Beggiatoa to overcome non-overlapping availabilities of electron donors and acceptors while gliding between oxic and sulfidic zones. The first look into the genome of these filamentous sulfur-oxidizing bacteria substantially deepens the understanding of their evolution and their contribution to sulfur and nitrogen cycling in marine sediments.

Mussmann, Marc; Hu, Fen Z.

2007-01-01

65

The complete genome sequence of Chlorobium tepidum TLS, a photosynthetic, anaerobic, green-sulfur bacterium  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The complete genome of the green-sulfur eubacterium Chlorobium tepidum TLS was determined to be a single circular chromosome of 2,154,946 bp. This represents the first genome sequence from the phylum Chlorobia, whose members perform anoxygenic photosynthesis by the reductive tricarboxylic acid cycle. Genome comparisons have identified genes in C. tepidum that are highly conserved among photosynthetic species. Many of these have no assigned function and may play novel role...

Eisen, Jonathan A.; Nelson, Karen E.; Paulsen, Ian T.; Heidelberg, John F.; Wu, Martin; Dodson, Robert J.; Deboy, Robert; Gwinn, Michelle L.; Nelson, William C.; Haft, Daniel H.; Hickey, Erin K.; Peterson, Jeremy D.; Durkin, A. Scott; Kolonay, James L.; Yang, Fan

2002-01-01

66

Two Genes Encoding New Carotenoid-Modifying Enzymes in the Green Sulfur Bacterium Chlorobium tepidum  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The green sulfur bacterium Chlorobium tepidum produces chlorobactene as its primary carotenoid. Small amounts of chlorobactene are hydroxylated by the enzyme CrtC and then glucosylated and acylated to produce chlorobactene glucoside laurate. The genes encoding the enzymes responsible for these modifications of chlorobactene, CT1987, and CT0967, have been identified by comparative genomics, and these genes were insertionally inactivated in C. tepidum to verify their predicted function. The gen...

Maresca, Julia A.; Bryant, Donald A.

2006-01-01

67

Genetic Manipulation of Carotenoid Biosynthesis in the Green Sulfur Bacterium Chlorobium tepidum†  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The green sulfur bacterium Chlorobium tepidum is a strict anaerobe and an obligate photoautotroph. On the basis of sequence similarity with known enzymes or sequence motifs, nine open reading frames encoding putative enzymes of carotenoid biosynthesis were identified in the genome sequence of C. tepidum, and all nine genes were inactivated. Analysis of the carotenoid composition in the resulting mutants allowed the genes encoding the following six enzymes to be identified: phytoene synthase (...

Frigaard, Niels-ulrik; Maresca, Julia A.; Yunker, Colleen E.; Jones, A. Daniel; Bryant, Donald A.

2004-01-01

68

Rapid one-step purification of the BChl-a containing FMO-protein from the green sulfur bacterium Chlorobium tepidum using a high efficiency immunomatrix.  

Science.gov (United States)

A new and rapid procedure has been developed for the isolation of the bacteriochlorophyll a-containing Fenna-Matthews-Olson (FMO)-protein from green sulfur bacteria. Polyclonal antibodies raised against the FMO-protein of Chlorobium (Chl.) tepidum were employed in the preparation of an antibody column utilizing immobilized protein A as the matrix. The antibody column afforded essentially a one-step purification process, resulting in preparations that were free from contaminating pigments and proteins. This was evidenced by absorption spectroscopy, SDS-PAGE, and fluorescence emission. PMID:16228508

Hu, Diane D; Blankenship, Robert E

2002-01-01

69

Purification of ferredoxins and their reaction with purified reaction center complex from the green sulfur bacterium Chlorobium tepidum.  

Science.gov (United States)

Four ferredoxin (Fd) fractions, namely, FdA-D were purified from the green sulfur bacterium Chlorobium tepidum. Their absorption spectra are typical of 2[4Fe-4S] cluster type Fds with peaks at about 385 and 280 nm and a shoulder at about 305 nm. The A(385)/A(280) ratios of the purified Fds were 0.76-0.80. Analysis of the N-terminal amino acid sequences of these Fds (15-25 residues) revealed that those of FdA and FdB completely agree with those deduced from the genes, fdx3 and fdx2, respectively, found in this bacterium (Chung and Bryant, personal communication). The N-terminal amino acid sequences of FdC and FdD (15 residues) were identical, and agree with that deduced from the gene fdx1 (Chung and Bryant, personal communication). The A(385) values of these Fds were unchanged when they were stored for a month at -80 degrees C under aerobic conditions and decreased by 10-15% when they were stored for 6 days at 4 degrees C under aerobic conditions, indicating that they are not extremely unstable. In the presence of Fd-NADP(+) reductase from spinach, and a purified reaction center (RC) preparation from C. tepidum composed of five kinds of polypeptides, these Fds supported the photoreduction of NADP(+) at room temperature with the following K(m) and V(max) (in micromol NADP(+) micromol BChl a(-1) h(-1)): FdA, 2.0 microm and 258; FdB, 0.49 microM and 304; FdC, 1.13 microM and 226; FdD, 0.5 microM and 242; spinach Fd, 0.54 microM and 183. The V(max) value of FdB was more than twice that previously reported for purified RC preparations from green sulfur bacteria. PMID:11115649

Seo, D; Tomioka, A; Kusumoto, N; Kamo, M; Enami, I; Sakurai, H

2001-01-19

70

Chemolithotrophic sulfur-oxidizing bacteria from the galapagos rift hydrothermal vents.  

Science.gov (United States)

Three distinct physiological types of sulfur-oxidizing bacteria were enriched and isolated from samples collected at several deep-sea hydrothermal vents (2,550 m) of the Galapagos Rift ocean floor spreading center. Twelve strains of the obligately chemolithotrophic genus Thiomicrospira were obtained from venting water and from microbial mats covering surfaces in the immediate vicinity of the vents. From these and other sources two types of obligately heterotrophic sulfur oxidizers were repeatedly isolated that presumably oxidized thiosulfate either to sulfate (acid producing; 9 strains) or to polythionates (base producing; 74 strains). The former were thiobacilli-like, exhibiting a thiosulfate-stimulated increase in growth and CO(2) incorporation, whereas the latter were similar to previously encountered pseudomonad-like heterotrophs. The presence of chemolithotrophic sulfur-oxidizing bacteria in the sulfide-containing hydrothermal water supports the hypothesis that chemosynthesis provides a substantial primary food source for the rich populations of invertebrates found in the immediate vicinity of the vents. PMID:16345831

Ruby, E G; Wirsen, C O; Jannasch, H W

1981-08-01

71

Accumulation of chlorophyllous pigments esterified with the geranylgeranyl group and photosynthetic competence in the CT2256-deleted mutant of the green sulfur bacterium Chlorobium tepidum.  

Science.gov (United States)

Green sulfur bacteria contain chlorophyllous pigments, chlorophyll (Chl) aPD and bacteriochlorophyll (BChl) aP, esterified with Delta2,6-phytadienol and phytol, respectively, which would be produced by reduction of the geranylgeranyl group at the C-17 propionate residue. In the genome of Chlorobium tepidum, two paralogous genes presumably encoding geranylgeranyl reductase, CT1232 and CT2256, are found. The deletion mutants of the CT1232 and CT2256 genes were constructed using an insertional inactivation method in order to clarify the biosynthetic process of the Delta2,6-phytadienyl and phytyl groups in green sulfur bacteria. The compositions of chlorophyllous pigments in the two mutants were determined by LC-MS analysis. The CT2256-deleted mutant accumulated Chl aGG and BChl aGG esterified with geranylgeraniol, indicating that CT2256 was involved in the production of both Delta2,6-phytadienyl and phytyl groups. The relatively high fluorescence emission from chlorosomes in the mutant also suggested some hindrance of the energy transfer from chlorosomes to the reaction center complex. However, the CT1232-deleted mutant almost showed no apparent phenotype compared to the wild type. Furthermore, the purple bacterium Rhodobacter capsulatus mutant defective in the bchP gene was partially complemented with the CT2256 gene; BChl aP was synthesized in the mutant in addition to accumulating other intermediates. PMID:18846281

Harada, Jiro; Miyago, Shohei; Mizoguchi, Tadashi; Azai, Chihiro; Inoue, Kazuhito; Tamiaki, Hitoshi; Oh-oka, Hirozo

2008-10-01

72

Genetic transfer by conjugation in the thermophilic green sulfur bacterium Chlorobium tepidum.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The broad-host-range IncQ group plasmids pDSK519 and pGSS33 were transferred by conjugation from Escherichia coli into the thermophilic green sulfur bacterium Chlorobium tepidum. C. tepidum exconjugants expressed the kanamycin and ampicillin-chloramphenicol resistances encoded by pDSK519 and pGSS33, respectively. Ampicillin resistance was a particularly good marker for selection in C. tepidum. Both pDSK519 and pGSS33 were stably maintained in C. tepidum at temperatures below 42 degrees C and ...

Wahlund, T. M.; Madigan, M. T.

1995-01-01

73

An integrated method incorporating sulfur-oxidizing bacteria and electrokinetics to enhance removal of copper from contaminated soil  

Energy Technology Data Exchange (ETDEWEB)

The combination of bioleaching and electrokinetics for the remediation of metal contaminated land has been investigated. In bioleaching, bacteria convert reduced sulfur compounds to sulfuric acid, acidifying soil and mobilizing metal ions. In electrokinetics, DC current acidifies soil, and mobilized metals are transported to the cathode by electromigration. When bioleaching was applied to silt soil artificially contaminated with seven metals and amended with sulfur, bacterial activity was partially inhibited and limited acidification occurred. Electrokinetic treatment of silt soil contaminated solely with 1000 mg/kg copper nitrate showed 89% removal of copper from the soil within 15 days. To combine bioleaching and electrokinetics sequentially, preliminary partial acidification was performed by amending copper-contaminated soil with sulfur (to 5% w/w) and incubating at constant moisture (30% w/w) and temperature (20 C) for 90 days. Indigenous sulfur oxidizing bacteria partially acidified the soil from pH 8.1 to 5.4. This soil was then treated by electrokinetics yielding 86% copper removal in 16 days. In the combined process, electrokinetics stimulated sulfur oxidation, by removing inhibitory factors, yielding a 5.1-fold increase in soil sulfate concentration. Preacidification by sulfur-oxidizing bacteria increased the cost-effectiveness of the electrokinetic treatment by reducing the power requirement by 66%.

Maini, G.; Sharman, A.K.; Sunderland, G.; Knowles, C.J.; Jackman, S.A.

2000-03-15

74

Chemical protection of bacteria and cultured mammalian cells by sulfur-containing compounds  

International Nuclear Information System (INIS)

Protection by sulfur-containing compounds was studied using bacteria E. coli Bsub(H) and cultured mouse leukemic cells, L 5178 Y, and the protective mechanisms were discussed. The dose reduction factors of non-sulfhydryl compounds observed in the bacteria were the same as those observed in mammalian cells, and the protective activity of these compounds was proportional to their reaction rates with hydroxyl radicals. On the other hand, sulfhydryl compounds, with the exception of glutathione, offered a much greater protection than was anticipated from their radical scavenging activity. From studies under anoxia, the protection of cysteine was explained by its OH scavenging and competition with oxygen. In addition, for MEA, protection against the direct action of radiation was suggested. This was supported by the significant protection in the frozen state. (author)

1975-01-01

75

Comparative proteomics and activity of a green sulfur bacterium through the water column of Lake Cadagno, Switzerland.  

Science.gov (United States)

Primary production in the meromictic Lake Cadagno, Switzerland, is dominated by anoxygenic photosynthesis. The green sulfur bacterium Chlorobium clathratiforme is the dominant phototrophic organism in the lake, comprising more than half of the bacterial population, and its biomass increases 3.8-fold over the summer. Cells from four positions in the water column were used for comparative analysis of the Chl. clathratiforme proteome in order to investigate changes in protein composition in response to the chemical and physical gradient in their environment, with special focus on how the bacteria survive in the dark. Although metagenomic data are not available for Lake Cadagno, proteome analysis was possible based on the completely sequenced genome of an isolated strain of Chl. clathratiforme. Using LC-MS/MS we identified 1321 Chl. clathratiforme proteins in Lake Cadagno and quantitatively compared 621 of these in the four samples. Our results showed that compared with cells obtained from the photic zone, cells collected from the dark part of the water column had the same expression level of key enzymes involved in carbon metabolism and photosynthetic light harvesting. However, most proteins participating in nitrogen and sulfur metabolism were twofold less abundant in the dark. From the proteome analysis we were able to show that Chl. clathratiforme in the photic zone contains enzymes for fixation of N(2) and the complete oxidation of sulfide to sulfate while these processes are probably not active in the dark. Instead we propose that Chl. clathratiforme cells in the dark part of the water column obtain energy for maintenance from the fermentation of polyglucose. Based on the observed protein compositions we have constructed possible pathways for C, N and S metabolism in Chl. clathratiforme. PMID:20731699

Habicht, Kirsten S; Miller, Mette; Cox, Raymond P; Frigaard, Niels-Ulrik; Tonolla, Mauro; Peduzzi, Sandro; Falkenby, Lasse G; Andersen, Jens S

2011-01-01

76

Prosthecochloris indica sp. nov., a novel green sulfur bacterium from a marine aquaculture pond, Kakinada, India.  

Science.gov (United States)

A green sulfur bacterium, strain JAGS6T was isolated from a marine aquaculture pond located near Kakinada on the east coast of India. Cells of strain JAGS6T were Gram-negative, non-motile, coccoid, 1-1.2 microm in diameter, with prosthecae. Phylogenetic analysis on the basis of 16S rRNA gene sequences showed that strain JAGS6T clusters with members of the genus Prosthecochloris and the sequence similarity with the nearest relative, Prosthecochloris vibrioformis, is 96.7%. Cultures of strain JAGS6T are green in color and the cells contain bacteriochlorophyll c and most likely carotenoids of the chlorobactene series as photosynthetic pigments. Strain JAGS6T is mesophilic, halotolerant (up to 7% NaCl) and is obligately phototrophic, utilizing sulfide but not thiosulfate as a photosynthetic electron donor. Sulfur globules are deposited outside the cells during oxidation of sulfide. On the basis of 16S rRNA gene sequence analysis and its morphological and physiological characteristics, strain JAGS6T is distinct from described species of the genus Prosthecochloris and we propose to describe it as a new species, Prosthecochloris indica, sp. nov. The type strain is JAGS6T (=JCM 13299T=ATCC BAA1214T). PMID:19436133

Anil Kumar, Pinnaka; Naga Radha Srinivas, Tanuku; Sasikala, Chintalapati; Venkata Ramana, Chintalapati; Süling, Jorg; Imhoff, Johannes

2009-04-01

77

A reconstituted light-harvesting complex from the green sulfur bacterium Chlorobium tepidum containing CsmA and bacteriochlorophyll a.  

Science.gov (United States)

Green sulfur bacteria possess two light-harvesting antenna systems, the chlorosome and the Fenna-Matthews-Olson (FMO) protein. In addition to self-aggregated bacteriochlorophyll (BChl) c, chlorosomes of Chlorobium tepidum contain a small amount of BChl a (ratio 100:1). The chlorosomal BChl a is associated with CsmA, a 6.2 kDa protein that accounts for more than 50% of the protein content of chlorosomes. This CsmA-BChl a complex is located in the chlorosome baseplate with the hydrophilic C-terminal part of CsmA in contact with the FMO protein. CsmA was purified from Chl. tepidum. Isolated chlorosomes were lyophilized and extracted with chloroform/methanol (1:1, v/v). The extract was further purified using gel filtration and reverse-phase HPLC and the purity of the preparation confirmed by SDS-PAGE. Mass spectrometric analysis showed an m/z of 6154.8, in agreement with the calculated mass of the csmA gene product after C-terminal processing. CD spectroscopy of the isolated protein showed that the main structural motif was an alpha-helix. We have reconstituted the isolated CsmA protein with BChl a in micelles of n-octyl beta-d-glucopyranoside. The resulting preparation reproduced the spectral characteristics of the CsmA-BChl a complex present in the chlorosome baseplate. PMID:18177020

Pedersen, Marie Ø; Pham, Lan; Steensgaard, Dorte B; Miller, Mette

2008-02-01

78

Who is in there?: exploration of endophytic bacteria within the siphonous green seaweed Bryopsis (Bryopsidales, Chlorophyta)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Associations between marine seaweeds and bacteria are widespread, with endobiotic bacterial-algal interactions being described for over 40 years. Also within the siphonous marine green alga Bryopsis, intracellular bacteria have been visualized by electron microscopy in the early '70s, but were up to now never molecularly analyzed. To study this partnership, we examined the presence and phylogenetic diversity of microbial communities within the cytoplasm of two Bryopsis species by combining fl...

Hollants, Joke; Leroux, Olivier; Leliaert, Fre?de?rik; Decleyre, Helen; Clerck, Olivier; Willems, Anne

2011-01-01

79

Who Is in There? Exploration of Endophytic Bacteria within the Siphonous Green Seaweed Bryopsis (Bryopsidales, Chlorophyta)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Associations between marine seaweeds and bacteria are widespread, with endobiotic bacterial-algal interactions being described for over 40 years. Also within the siphonous marine green alga Bryopsis, intracellular bacteria have been visualized by electron microscopy in the early ‘70s, but were up to now never molecularly analyzed. To study this partnership, we examined the presence and phylogenetic diversity of microbial communities within the cytoplasm of two Bryopsis species by combining ...

Hollants, Joke; Leroux, Olivier; Leliaert, Frederik; Decleyre, Helen; Clerck, Olivier; Willems, Anne

2011-01-01

80

Who is in there?: exploration of endophytic bacteria within the siphonous green seaweed Bryopsis (Bryopsidales, Chlorophyta)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Associations between marine seaweeds and bacteria are widespread, with endobiotic bacterial-algal interactions being described for over 40 years. Also within the siphonous marine green alga Bryopsis, intracellular bacteria have been visualized by electron microscopy in the early ‘70s, but were up to now never molecularly analyzed. To study this partnership, we examined the presence and phylogenetic diversity of microbial communities within the cytoplasm of two Bryopsis species by combining ...

Hollants, Joke; Leroux, Olivier; Leliaert, Fre?de?rik; Decleyre, Helen; Clerck, Olivier; Willems, Anne

2011-01-01

 
 
 
 
81

Green electricity production with living plants and bacteria in a fuel cell  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The world needs sustainable, efficient, and renewable energy production. We present the plant microbial fuel cell (plant-MFC), a concept that exploits a bioenergy source in situ. In the plant-MFC, plants and bacteria were present to convert solar energy into green electricity. The principal idea is that plants produce rhizodeposits, mostly in the form of carbohydrates, and the bacteria convert these rhizodeposits into electrical energy via the fuel cell. Here, we demonstrated the proof of pri...

Strik, D. P. B. T. B.; Hamelers, H. V. M.; Snel, J. F. H.; Buisman, C. J. N.

2008-01-01

82

Isolation of lactic acid bacteria for its possible use in the fermentation of green algerian olives  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study was undertaken with the aim of obtaining lactic acid bacteria with the ability to ferment olives for possible use as starter cultures. For this reason, 32 isolates of lactic acid bacteria isolated from the spontaneous fermentation of green olives were characterized and identified on the basis of morphological and biochemical criteria. 14 of them were identified as Lactococcus lactis, 11 isolates as Lactobacillus plantarum and 7 isolates as Enterococcus sp. Of t...

Mourad, Kacem; Halima, Zadi-karam; Nour-eddine, Karam

2004-01-01

83

Identification and characterization of sulfur-oxidizing bacteria in an artificial wetland that treats wastewater from a tannery.  

Science.gov (United States)

Wastewater from tanneries contains high concentrations of organic matter, chromium, nitrogen, and sulfur compounds. In this study, an artificial wetland is is used as the tertiary treatment in a tannery in León Gto., México. It consists of three subplots with an area of about 450 m2. Two subplots were planted with Typha sp. and the third with Scirpus americanus. Geochemical analyses along the flowpath of the wetland show that contaminants were effectively attenuated. The most probable number technique was used to determine rhizospheric microbial populations involved in the sulfur cycle and suggested that there were 104-10(6) cells g(-1) sediment of sulfate-reducing bacteria and 10(2)-10(5) of sulfur-oxidizing bacteria (SOB). Representatives of SOB were isolated on media containing thiosulfate. Phylogenetic analysis of 16S rRNA of SOB isolates shows that they belong to the genera Acinetobacter, Alcaligenes, Ochrobactrum, and Pseudomonas. Most of the isolates are organotrophic and can oxidize reduced sulfur compounds such as elemental sulfur or thiosulfate, accumulating thiosulfate, or tetrathionate during growth. All isolates can use reduced-sulfur compounds as their sole sulfur source and some can use nitrate as an electron acceptor to grow anaerobically. Our results illustrate the relevance of SOB in the functioning of the wetland constructed for tannery wastewater remediation. PMID:19260219

Pacheco Aguilar, Juan Ramiro; Peña Cabriales, Juan José; Maldonado Vega, María

2008-01-01

84

Archaea, Bacteria, and Sulfur-Cycling in a Shallow-Sea Hydrothermal Ecosystem  

Science.gov (United States)

Deep-sea hydrothermal systems are windows to the marine subsurface biosphere. It often is overlooked, however, that their far more accessible shallow-sea counterparts can serve the same purpose. To characterize the extent, diversity, and activity of the subsurface microbial community in the shallow vent ecosystem near Panarea Island (Italy), sediment cores were analyzed with a broad array of analytical techniques. Vent fluid and sediment temperatures reached up to 135 °C, with pHs in porewaters generally measuring 5-6. Microsensor profiles marked a very sharp oxic-anoxic transition, and when coupled to pH and H2S profiles, pointed to aerobic sulfide oxidation. With increasing depth from the sediment-water interface, porewater analyses showed a decrease in sulfate levels from ~30 mM to thermophilic sulfate reducing and acidophilic sulfide oxidizing bacteria. Results from several sites also showed that with increasing depth and temperature, biomass abundance of archaea generally increased relative to that of bacteria. Lastly, DGGE fingerprinting and 16S rRNA clone libraries from several depths at Hot Lake revealed a moderate diversity of bacteria, dominated by Epsilonproteobacteria; this class is known to catalyze both sulfur reduction and oxidation reactions, and to mediate the formation of iron-sulfides, including framboidal pyrite. Archaeal sequences at Hot Lake are dominated by uncultured Thermoplasmatales, plus several sequences in the Korarchaeota.

Amend, J. P.; Huang, C.; Amann, R.; Bach, W.; Meyerdierks, A.; Price, R. E.; Schubotz, F.; Summons, R. E.; Wenzhoefer, F.

2009-12-01

85

Electron transfer kinetics in purified reaction centers from the green sulfur bacterium Chlorobium tepidum studied by multiple-flash excitation.  

Science.gov (United States)

Reaction center preparations from the green sulfur bacterium Chlorobium tepidum, which contain monoheme cytochrome c, were studied by flash-absorption spectroscopy in the near-UV, visible, and near-infrared regions. The decay kinetics of the photooxidized primary donor P840(+), together with the amount of photooxidized cytochrome c, were analyzed along a series of four flashes spaced by 1 ms: 95% of the P840(+) was reduced by cytochrome c with a t(1/2) of approximately 65 micros after the first flash, 80% with a t(1/2) of approximately 100 micros after the second flash, and 23% with a t(1/2) of approximately 100 micros after the third flash; after the fourth flash, almost no cytochrome c oxidation occurred. The observed rates, the establishment of redox equilibrium after each flash, and the total amount of photooxidizable cytochrome c are consistent with the presence of two equivalent cytochrome c molecules per photooxidizable P840. The data are well fitted assuming a standard free energy change DeltaG degrees of -53 meV for electron transfer from one cytochrome c to P840(+), DeltaG degrees being independent of the oxidation state of the other cytochrome c. These observations support a model with two monoheme cytochromes c which are symmetrically arranged around the reaction center core. From the ratio of menaquinone-7 to the bacteriochlorophyll pigment absorbing at 663 nm, it was estimated that our preparations contain 0.6-1.2 menaquinone-7 molecules per reaction center. However, no transient signal due to menaquinone could be observed between 360 and 450 nm in the time window from 10 ns to 4 micros. No recombination reaction between the primary partners P840(+) and A(0)(-) could be detected under normal conditions. Such a recombination was observed (t(1/2) approximately 19 ns) under highly reducing conditions or after accumulation of three electrons on the acceptor side during a series of flashes, showing that the secondary acceptors can stabilize three electrons. From our data, there is no evidence for involvement of menaquinone in charge separation in the reaction center of green sulfur bacteria. PMID:10508417

Kusumoto, N; Sétif, P; Brettel, K; Seo, D; Sakurai, H

1999-09-14

86

Sulfur-Oxidizing Bacteria in Soap Lake (Washington State), a Meromictic, Haloalkaline Lake with an Unprecedented High Sulfide Content?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Culture-dependent and -independent techniques were used to study the diversity of chemolithoautotrophic sulfur-oxidizing bacteria in Soap Lake (Washington State), a meromictic, haloalkaline lake containing an unprecedentedly high sulfide concentration in the anoxic monimolimnion. Both approaches revealed the dominance of bacteria belonging to the genus Thioalkalimicrobium, which are common inhabitants of soda lakes. A dense population of Thioalkalimicrobium (up to 107 cells/ml) was found at t...

Sorokin, Dimitry Y.; Foti, Mirjam; Pinkart, Holly C.; Muyzer, Gerard

2007-01-01

87

Removal of sediment and bacteria from water using green chemistry.  

Science.gov (United States)

Although nearly all newly derived water purification methods have improved the water quality in developing countries, few have been accepted and maintained for long-term use. Field studies indicate that the most beneficial methods use indigenous resources, as they are both accessible and accepted by communities they help. In an effort to implement a material that will meet community needs, two fractions of mucilage gum were extracted from the Opuntia ficus-indica cactus and tested as flocculation agents against sediment and bacterial contamination. As diatomic ions are known to affect both mucilage and promote cell aggregation, CaCl(2) was studied in conjunction and compared with mucilage as a bacteria removal method. To evaluate performance, ion-rich waters that mimic natural water bodies were prepared. Column tests containing suspensions of the sediment kaolin exhibited particle flocculation and settling rates up to 13.2 cm/min with mucilage versus control settling rates of 0.5 cm/min. Bacillus cereus tests displayed flocculation and improved settling times with mucilage concentrations lower than 5 ppm and removal rates between 97 and 98% were observed for high bacteria concentration tests (>10(8) cells/ml). This natural material not only displays water purification abilities, but it is also affordable, renewable and readily available. PMID:20369814

Buttice, Audrey L; Stroot, Joyce M; Lim, Daniel V; Stroot, Peter G; Alcantar, Norma A

2010-05-01

88

SoxAX Binding Protein, a Novel Component of the Thiosulfate-Oxidizing Multienzyme System in the Green Sulfur Bacterium Chlorobium tepidum?  

Science.gov (United States)

From the photosynthetic green sulfur bacterium Chlorobium tepidum (pro synon. Chlorobaculum tepidum), we have purified three factors indispensable for the thiosulfate-dependent reduction of the small, monoheme cytochrome c554. These are homologues of sulfur-oxidizing (Sox) system factors found in various thiosulfate-oxidizing bacteria. The first factor is SoxYZ that serves as the acceptor for the reaction intermediates. The second factor is monomeric SoxB that is proposed to catalyze the hydrolytic cleavage of sulfate from the SoxYZ-bound oxidized product of thiosulfate. The third factor is the trimeric cytochrome c551, composed of the monoheme cytochrome SoxA, the monoheme cytochrome SoxX, and the product of the hypothetical open reading frame CT1020. The last three components were expressed separately in Escherichia coli cells and purified to homogeneity. In the presence of the other two Sox factors, the recombinant SoxA and SoxX showed a low but discernible thiosulfate-dependent cytochrome c554 reduction activity. The further addition of the recombinant CT1020 protein greatly increased the activity, and the total activity was as high as that of the native SoxAX-CT1020 protein complex. The recombinant CT1020 protein participated in the formation of a tight complex with SoxA and SoxX and will be referred to as SAXB (SoxAX binding protein). Homologues of the SAXB gene are found in many strains, comprising roughly about one-third of the thiosulfate-oxidizing bacteria whose sox gene cluster sequences have been deposited so far and ranging over the Chlorobiaciae, Chromatiaceae, Hydrogenophilaceae, Oceanospirillaceae, etc. Each of the deduced SoxA and SoxX proteins of these bacteria constitute groups that are distinct from those found in bacteria that apparently lack SAXB gene homologues.

Ogawa, Takuro; Furusawa, Toshinari; Nomura, Ryohei; Seo, Daisuke; Hosoya-Matsuda, Naomi; Sakurai, Hidehiro; Inoue, Kazuhito

2008-01-01

89

SoxAX binding protein, a novel component of the thiosulfate-oxidizing multienzyme system in the green sulfur bacterium Chlorobium tepidum.  

Science.gov (United States)

From the photosynthetic green sulfur bacterium Chlorobium tepidum (pro synon. Chlorobaculum tepidum), we have purified three factors indispensable for the thiosulfate-dependent reduction of the small, monoheme cytochrome c(554). These are homologues of sulfur-oxidizing (Sox) system factors found in various thiosulfate-oxidizing bacteria. The first factor is SoxYZ that serves as the acceptor for the reaction intermediates. The second factor is monomeric SoxB that is proposed to catalyze the hydrolytic cleavage of sulfate from the SoxYZ-bound oxidized product of thiosulfate. The third factor is the trimeric cytochrome c(551), composed of the monoheme cytochrome SoxA, the monoheme cytochrome SoxX, and the product of the hypothetical open reading frame CT1020. The last three components were expressed separately in Escherichia coli cells and purified to homogeneity. In the presence of the other two Sox factors, the recombinant SoxA and SoxX showed a low but discernible thiosulfate-dependent cytochrome c(554) reduction activity. The further addition of the recombinant CT1020 protein greatly increased the activity, and the total activity was as high as that of the native SoxAX-CT1020 protein complex. The recombinant CT1020 protein participated in the formation of a tight complex with SoxA and SoxX and will be referred to as SAXB (SoxAX binding protein). Homologues of the SAXB gene are found in many strains, comprising roughly about one-third of the thiosulfate-oxidizing bacteria whose sox gene cluster sequences have been deposited so far and ranging over the Chlorobiaciae, Chromatiaceae, Hydrogenophilaceae, Oceanospirillaceae, etc. Each of the deduced SoxA and SoxX proteins of these bacteria constitute groups that are distinct from those found in bacteria that apparently lack SAXB gene homologues. PMID:18641134

Ogawa, Takuro; Furusawa, Toshinari; Nomura, Ryohei; Seo, Daisuke; Hosoya-Matsuda, Naomi; Sakurai, Hidehiro; Inoue, Kazuhito

2008-09-01

90

An overview of the bacteria and archaea involved in removal of inorganic and organic sulfur compounds from coal  

Energy Technology Data Exchange (ETDEWEB)

Of special importance for biohydrometallurgy are acidophilic chemolithotrophic bacteria from a number of different taxonomic groups, namely: the genera of [ital Thiobacillus] and [ital Leptospirillum], moderately thermophilic bacteria which were combined into the group [ital Sulfobacillus-Alicyclobacillus], and archaea of the genera [ital Sulfolobus, Acidianus, Metallosphaera], and [ital Sulfurococcus]. These bacteria are able to oxidize one or more of the following compounds Fe[sup 2+], S[sup 0] and sulfide minerals and to grow under extreme environmental conditions. Growth pH varies in the range from 1 to 5, growth temperature - from 2 to 90[degree]C. They can tolerate high concentration of metal ions. They possess a great physiological, biochemical and genetic variability. Some of them are important for removal of inorganic sulfur compounds from coals. Some types of coals and oils contain aromatic heterocyclic compounds with the C-S bond. Although a wide range of mostly heterotrophic and some chemolithotrophic bacteria, from bacteria and archaea to eucaryotes, participate in its transformation, only certain organisms have a unique capability of splitting this bond. They can remove organic sulfur-containing compounds from coal. The possibilities of application of bacteria in biological processing of coals are discussed. 74 refs., 2 figs., 5 tabs.

Karavaiko, G.I.; Lobyreva, L.B. (Russian Academy of Sciences, Moscow (Russian Federation). Inst. of Microbiology)

1994-11-01

91

Lamellar Organization of Pigments in Chlorosomes, the Light Harvesting Complexes of Green Photosynthetic Bacteria  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Chlorosomes of green photosynthetic bacteria constitute the most efficient light harvesting complexes found in nature. In addition, the chlorosome is the only known photosynthetic system where the majority of pigments (BChl) is not organized in pigment-protein complexes but instead is assembled into aggregates. Because of the unusual organization, the chlorosome structure has not been resolved and only models, in which BChl pigments were organized into large rods, were proposed on the basis o...

Ps?enc?i?k, J.; Ikonen, T. P.; Laurinma?ki, P.; Merckel, M. C.; Butcher, S. J.; Serimaa, R. E.; Tuma, R.

2004-01-01

92

Tetrazolium Reduction-Malachite Green Method for Assessing the Viability of Filamentous Bacteria in Activated Sludge  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A method was developed to assess the activity of filamentous bacteria in activated sludge. It involves the incubation of activated sludge with 2(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl tetrazolium chloride followed by staining with malachite green. Both cells and 2(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl tetrazolium chloride-formazan crystals can be observed in prepared specimens by using bright-field microscopy. This procedure allowed us to distinguish between inactive and actively metabol...

Bitton, Gabriel; Koopman, Ben

1982-01-01

93

Effects of stress hormones on the production of volatile sulfur compounds by periodontopathogenic bacteria  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Little is known about the effects of stress hormones on the etiologic agents of halitosis. Thus, the aim of this study was to evaluate in vitro the effects of adrenaline (ADR), noradrenaline (NA) and cortisol (CORT) on bacteria that produce volatile sulfur compounds (VSC), the major gases responsibl [...] e for bad breath. Cultures of Fusobacterium nucleatum (Fn), Porphyromonas endodontalis (Pe), Prevotella intermedia (Pi) and Porphyromonas gingivalis (Pg) were exposed to 50 µM ADR, NA and CORT or equivalent volumes of sterile water as controls for 12 and 24 h. Growth was evaluated based on absorbance at 660 nm. Portable gas chromatography was used to measure VSC concentrations. Kruskal-Wallis and the Dunn post-hoc test were used to compare the groups. For Fn, ADR, NA and CORT significantly reduced bacterial growth after 12 h and 24 h (p 0.05). In the Pi cultures, ADR, NA and CORT increased H2S (p

Caroline Morini, Calil; Gisele Mattos, Oliveira; Karina, Cogo; Antonio Carlos, Pereira; Fernanda Klein, Marcondes; Francisco Carlos, Groppo.

2014-06-11

94

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

Science.gov (United States)

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.

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

1989-01-01

95

Functional genes based analysis of sulfur-oxidizing bacteria community in sulfide removing bioreactor.  

Science.gov (United States)

Sulfur-oxidizing bacteria (SOB) are the main microorganisms that participate in the bioremediation of sulfide-rich wastewater. To reveal the SOB community structure and determine which members of SOB contribute to the sulfide oxidation in a sulfide-rich cloth printing and dyeing wastewater treatment plant, specific primer pairs dsrA 625F/877R, soxB 704F/1199R, and sqr 473F/982R based on the SOB functional genes encoding dissimilatory sulfite reductase, sulfate thioesterase/thiohydrolase, and sulfide: quinone oxidoreductase were designed. The restriction fragment length polymorphism analysis showed that the diversity indices and the abundance of each OTU have no significant changes after time, which suggested the SOB community in the sulfide removing bioreactor have high steady phylogenetic analysis of functional gene-based clone libraries detected the SOB from Chlorobia, ?-proteobacteria, ?-proteobacteria, and ?-proteobacteria. The combined clone library showed the presence of dominant members of the SOB species closely related to families Halothiobacillaceae (17%), Hydrogenophilaceae (14%), and Rhodocyclaceae (13%), which may contribute to the sulfide oxidation in wastewater treatment process. This work provides a precise understanding of SOB microbial community within sulfide removing bioreactor, and the result gives assistance for the optimization of the treatment systems for sulfide biological degradation. PMID:21212946

Luo, Jian-Fei; Lin, Wei-Tie; Guo, Yong

2011-04-01

96

Effects of stress hormones on the production of volatile sulfur compounds by periodontopathogenic bacteria.  

Science.gov (United States)

Little is known about the effects of stress hormones on the etiologic agents of halitosis. Thus, the aim of this study was to evaluate in vitro the effects of adrenaline (ADR), noradrenaline (NA) and cortisol (CORT) on bacteria that produce volatile sulfur compounds (VSC), the major gases responsible for bad breath. Cultures of Fusobacterium nucleatum (Fn), Porphyromonas endodontalis (Pe), Prevotella intermedia (Pi) and Porphyromonas gingivalis (Pg) were exposed to 50 µM ADR, NA and CORT or equivalent volumes of sterile water as controls for 12 and 24 h. Growth was evaluated based on absorbance at 660 nm. Portable gas chromatography was used to measure VSC concentrations. Kruskal-Wallis and the Dunn post-hoc test were used to compare the groups. For Fn, ADR, NA and CORT significantly reduced bacterial growth after 12 h and 24 h (pproduction (p0.05). In the Pi cultures, ADR, NA and CORT increased H2S (pproduction of sub-gingival species in vitro. This process appears to be complex and supports the association between stress and the production of VSC. PMID:24918364

Calil, Caroline Morini; Oliveira, Gisele Mattos; Cogo, Karina; Pereira, Antonio Carlos; Marcondes, Fernanda Klein; Groppo, Francisco Carlos

2014-01-01

97

Application of bacteria involved in the biological sulfur cycle for paper mill effluent purification  

Energy Technology Data Exchange (ETDEWEB)

In anaerobic wastewater treatment, the occurrence of biological sulfate reduction results in the formation of unwanted hydrogen sulfide, which is odorous, corrosive and toxic. In this paper, the role and application of bacteria in anaerobic and aerobic sulfur transformations are described and exemplified for the treatment of a paper mill wastewater. The sulfate containing wastewater first passes an anaerobic UASB reactor for bulk COD removal which is accompanied by the formation of biogas and hydrogen sulfide. In an aeration pond, the residual COD{sub organic} and the formed dissolved hydrogen sulfide are removed. The biogas, consisting of CH{sub 4} (80-90 vol.%), CO{sub 2} (10-20 vol.%) and H{sub 2}S (0.8-1.2 vol.%), is desulfurised prior to its combustion in a power generator thereby using a new biological process for H{sub 2}S removal. This process will be described in more detail in this paper. Biomass from the anaerobic bioreactor has a compact granular structure and contains a diverse microbial community. Therefore, other anaerobic bioreactors throughout the world are inoculated with biomass from this UASB reactor. The sludge was also successfully used in investigation on sulfate reduction with carbon monoxide as the electron donor and the conversion of methanethiol. This shows the biotechnological potential of this complex reactor biomass.

Janssen, Albert J.H. [Sub-department of Environmental Technology, Wageningen University, Wageningen (Netherlands); Shell Global Solutions Int. B.V., Amsterdam (Netherlands)], E-mail: albert.janssen@wur.nl; Lens, Piet N.L. [Sub-department of Environmental Technology, Wageningen University, Wageningen (Netherlands); Stams, Alfons J.M.; Plugge, Caroline M. [Laboratory of Microbiology, Wageningen University, Wageningen (Netherlands); Sorokin, Dimitri Y. [Department of Biotechnology, Delft (Netherlands); Institute of Microbiology, Russian Academy of Science, Moscow (Russian Federation); Muyzer, Gerard [Department of Biotechnology, Delft (Netherlands); Dijkman, Henk; Van Zessen, Erik [Paques B.V., Balk (Netherlands); Luimes, Peter [Industriewater Eerbeek B.V. Eerbeek (Netherlands); Buisman, Cees J.N. [Sub-department of Environmental Technology, Wageningen University, Wageningen (Netherlands)

2009-02-01

98

Application of bacteria involved in the biological sulfur cycle for paper mill effluent purification.  

Science.gov (United States)

In anaerobic wastewater treatment, the occurrence of biological sulfate reduction results in the formation of unwanted hydrogen sulfide, which is odorous, corrosive and toxic. In this paper, the role and application of bacteria in anaerobic and aerobic sulfur transformations are described and exemplified for the treatment of a paper mill wastewater. The sulfate containing wastewater first passes an anaerobic UASB reactor for bulk COD removal which is accompanied by the formation of biogas and hydrogen sulfide. In an aeration pond, the residual CODorganic and the formed dissolved hydrogen sulfide are removed. The biogas, consisting of CH4 (80-90 vol.%), CO2 (10-20 vol.%) and H2S (0.8-1.2 vol.%), is desulfurised prior to its combustion in a power generator thereby using a new biological process for H2S removal. This process will be described in more detail in this paper. Biomass from the anaerobic bioreactor has a compact granular structure and contains a diverse microbial community. Therefore, other anaerobic bioreactors throughout the world are inoculated with biomass from this UASB reactor. The sludge was also successfully used in investigation on sulfate reduction with carbon monoxide as the electron donor and the conversion of methanethiol. This shows the biotechnological potential of this complex reactor biomass. PMID:19027933

Janssen, Albert J H; Lens, Piet N L; Stams, Alfons J M; Plugge, Caroline M; Sorokin, Dimitri Y; Muyzer, Gerard; Dijkman, Henk; Van Zessen, Erik; Luimes, Peter; Buisman, Cees J N

2009-02-01

99

Community structure of filamentous, sheath-building sulfur bacteria, Thioploca spp, off the coast of Chile  

DEFF Research Database (Denmark)

The filamentous sulfur bacteria Thioploca spp, produce dense bacterial mats in the shelf area off the coast of Chile and Peru. The mat consists of common sheaths, shared by many filaments, that reach 5 to 10 cm dean into the sediment, The structure of the Thioploca communities off the Bay of Concepcion was investigated,vith respect to biomass, species distribution, and three-dimensional orientation of the sheaths, Thioploca sheaths and filaments were found across the whole shelf area within the oxygen minimum zone, The maximum wet weight of sheaths, 800 g m(-2), was found at a depth of 90 m, The bacterial filaments within the sheaths contributed about 10% of this weight, The highest density of filaments was found within the uppermost I cm of the mat, On the basis of diameter classes, it was possible to distinguish populations containing only Thioploca spp, from mixed populations containing Beggiatoa spp, Three distinct size classes of Thioploca spp. were found, two of which have been described previously as Thioploca araucae and Thioploca chileae. Many Thioploca filaments did not possess a visible sheath, and about 20% of the sheaths contained more than one Thioploca species. The three-dimensional sheath structure showed that Thioploca filaments can move from the surface and deep into the sediment.

Schulz, HN; Jørgensen, BB

1996-01-01

100

Application of bacteria involved in the biological sulfur cycle for paper mill effluent purification  

International Nuclear Information System (INIS)

In anaerobic wastewater treatment, the occurrence of biological sulfate reduction results in the formation of unwanted hydrogen sulfide, which is odorous, corrosive and toxic. In this paper, the role and application of bacteria in anaerobic and aerobic sulfur transformations are described and exemplified for the treatment of a paper mill wastewater. The sulfate containing wastewater first passes an anaerobic UASB reactor for bulk COD removal which is accompanied by the formation of biogas and hydrogen sulfide. In an aeration pond, the residual CODorganic and the formed dissolved hydrogen sulfide are removed. The biogas, consisting of CH4 (80-90 vol.%), CO2 (10-20 vol.%) and H2S (0.8-1.2 vol.%), is desulfurised prior to its combustion in a power generator thereby using a new biological process for H2S removal. This process will be described in more detail in this paper. Biomass from the anaerobic bioreactor has a compact granular structure and contains a diverse microbial community. Therefore, other anaerobic bioreactors throughout the world are inoculated with biomass from this UASB reactor. The sludge was also successfully used in investigation on sulfate reduction with carbon monoxide as the electron donor and the conversion of methanethiol. This shows the biotechnological potential of this complex reactor biomass

2009-02-01

 
 
 
 
101

Methods for removing malodorous sulfur compounds from pulp mill flue gases and the like by using green liquor  

Energy Technology Data Exchange (ETDEWEB)

This is an improved method for removing malodorous sulfur compounds from flue gases generated in kraft or sodium sulfite pulping operations and the like by the absorption process using green liquor, an aqueous solution containing sodium sulfide and sodium carbonate. The malodorous gas compounds, including hydrogen sulfide, methyl mercaptan, and dimethyl sulfide are preferentially absorbed by the sodium sulfide forming sodium hydrosulfide and methanol. Any sulfur dioxide in the gas is absorbed and neutralized by sodium carbonate. In this method carbon dioxide absorption is minimized and the formation of sodium bicarbonate is limited. Sodium bicarbonate formation is minimized in order to avoid its reaction with sodium hydrosulfide which would then release undesirable hydrogen sulfide during absorption, as well as to forestall the need to increase chemical and lime kiln capacity requirements when the green liquor returned to the kraft recovery process contains excess amounts of sodium bicarbonate.

Farin, W.G.

1984-02-14

102

Cultivation of Autotrophic Ammonia-Oxidizing Archaea from Marine Sediments in Coculture with Sulfur-Oxidizing Bacteria? †  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The role of ammonia-oxidizing archaea (AOA) in nitrogen cycling in marine sediments remains poorly characterized. In this study, we enriched and characterized AOA from marine sediments. Group I.1a crenarchaea closely related to those identified in marine sediments and “Candidatus Nitrosopumilus maritimus” (99.1 and 94.9% 16S rRNA and amoA gene sequence identities to the latter, respectively) were substantially enriched by coculture with sulfur-oxidizing bacteria (SOB). The selective enric...

2010-01-01

103

Manipulation of the bacteriochlorophyll c homolog distribution in the green sulfur bacterium Chlorobium tepidum.  

Science.gov (United States)

We have shown that the green sulfur bacterium Chlorobium tepidum can be grown in batch culture supplemented with potentially toxic fatty alcohols without a major effect on the growth rate if the concentration of the alcohols is kept low either by programmed addition or by adding the alcohol as an inclusion complex with ?-cyclodextrin. HPLC and GC analysis of pigment extracts from the supplemented cells showed that the fatty alcohols were incorporated into bacteriochlorophyll c as the esterifying alcohol. It was possible to change up to 43% of the naturally occurring farnesyl ester of bacteriochlorophyll c with the added alcohol. This change in the homolog composition had no effect on the spectral properties of the cells when farnesol was partially replaced by stearol, phytol or geranylgeraniol. However, with dodecanol we obtained a blue-shift of 6 nm of the Qy band of the bacteriochlorophyll c and a concomitant change in the fluorescence emission was observed. The possible significance of these findings is discussed in the light of current ideas about bacteriochlorophyll organization in the chlorosomes. PMID:24271479

Steensgaard, D B; Cox, R P; Miller, M

1996-06-01

104

Purification and characterization of ferredoxin-NAD(P)(+) reductase from the green sulfur bacterium Chlorobium tepidum.  

Science.gov (United States)

Ferredoxin-NAD(P)(+) reductase [EC 1.18.1.3, 1.18.1.2] was isolated from the green sulfur bacterium Chlorobium tepidum and purified to homogeneity. The molecular mass of the subunit is 42 kDa, as deduced by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The molecular mass of the native enzyme is approximately 90 kDa, estimated by gel-permeation chromatography, and is thus a homodimer. The enzyme contains one FAD per subunit and has absorption maxima at about 272, 385, and 466 nm. In the presence of ferredoxin (Fd) and reaction center (RC) complex from C. tepidum, it efficiently catalyzes photoreduction of both NADP(+) and NAD(+). When concentrations of NADP(+) exceeded 10 microM, NADP(+) photoreduction rates decreased with increased concentration. The inhibition by high concentrations of substrate was not observed with NAD(+). It also reduces 2,6-dichlorophenol-indophenol (DPIP) and molecular oxygen with either NADPH or NADH as efficient electron donors. It showed NADPH diaphorase activity about two times higher than NADH diaphorase activity in DPIP reduction assays at NAD(P)H concentrations less than 0.1 mM. At 0.5 mM NAD(P)H, the two activities were about the same, and at 1 mM, the former activity was slightly lower than the latter. PMID:12009411

Seo, Daisuke; Sakurai, Hidehiro

2002-05-20

105

Chlorobium ferrooxidans sp. nov., a phototrophic green sulfur bacterium that oxidizes ferrous iron in coculture with a "Geospirillum" sp. strain  

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A green phototrophic bacterium was enriched with ferrous iron as sole electron donor and was isolated in defined coculture with a spirilloid chemoheterotrophic bacterium. The coculture oxidized ferrous iron to ferric iron with stoichiometric formation of cell mass from carbon dioxide. Sulfide, thiosulfate, or elemental sulfur was not used as electron donor in the light. Hydrogen or acetate in the presence of ferrous iron increased the cell yield of the phototrophic partner, and hydrogen could...

Heising, Silke; Richter, Lothar; Ludwig, Wolfgang; Schink, Bernhard

1999-01-01

106

Roseobacter clade bacteria are abundant in coastal sediments and encode a novel combination of sulfur oxidation genes.  

Science.gov (United States)

Roseobacter clade bacteria (RCB) are abundant in marine bacterioplankton worldwide and central to pelagic sulfur cycling. Very little is known about their abundance and function in marine sediments. We investigated the abundance, diversity and sulfur oxidation potential of RCB in surface sediments of two tidal flats. Here, RCB accounted for up to 9.6% of all cells and exceeded abundances commonly known for pelagic RCB by 1000-fold as revealed by fluorescence in situ hybridization (FISH). Phylogenetic analysis of 16S rRNA and sulfate thiohydrolase (SoxB) genes indicated diverse, possibly sulfur-oxidizing RCB related to sequences known from bacterioplankton and marine biofilms. To investigate the sulfur oxidation potential of RCB in sediments in more detail, we analyzed a metagenomic fragment from a RCB. This fragment encoded the reverse dissimilatory sulfite reductase (rDSR) pathway, which was not yet found in RCB, a novel type of sulfite dehydrogenase (SoeABC) and the Sox multi-enzyme complex including the SoxCD subunits. This was unexpected as soxCD and dsr genes were presumed to be mutually exclusive in sulfur-oxidizing prokaryotes. This unique gene arrangement would allow a metabolic flexibility beyond known sulfur-oxidizing pathways. We confirmed the presence of dsrA by geneFISH in closely related RCB from an enrichment culture. Our results show that RCB are an integral part of the microbial community in marine sediments, where they possibly oxidize inorganic and organic sulfur compounds in oxic and suboxic sediment layers. PMID:22739490

Lenk, Sabine; Moraru, Cristina; Hahnke, Sarah; Arnds, Julia; Richter, Michael; Kube, Michael; Reinhardt, Richard; Brinkhoff, Thorsten; Harder, Jens; Amann, Rudolf; Mußmann, Marc

2012-12-01

107

The reductive tricarboxylic acid cycle of carbon dioxide assimilation: initial studies and purification of ATP-citrate lyase from the green sulfur bacterium Chlorobium tepidum.  

Science.gov (United States)

Carbon dioxide is fixed largely by the reductive tricarboxylic acid (RTCA) cycle in green sulfur bacteria. One of the key enzymes, ATP-citrate lyase, was purified to apparent homogeneity from the moderately thermophilic green sulfur bacterium Chlorobium tepidum. The molecular weight of the native enzyme was about 550,000, and the preponderance of evidence indicated that the protein is composed of identical subunits (Mr of approximately 135,000) which degraded to two major proteins with Mrs of approximately 65,000 and approximately 42,000. Western immunoblots and in vitro phosphorylation experiments indicated that these two species could have been the result of proteolysis by an endogenous protease, similar to what has been observed with mammalian, yeast, and mold ATP-citrate lyase. In addition to apparent structural similarities, the catalytic properties of C. tepidum ATP-citrate lyase showed marked similarities to the eukaryotic enzyme, with significant differences from other prokaryotic ATP-citrate lyases, including the enzyme from the closely related organism Chlorobium limicola. Phosphorylation of C. tepidum ATP-citrate lyase occurred, presumably on a histidine residue at the active site, similar to the case for the mammalian enzyme. In contrast to the situation observed for other prokaryotic ATP-citrate lyase enzymes, the C. tepidum enzyme was not able to replace ATP and GTP for activity or use Cu2+ to replace Mg2+ for enzyme activity. Given the apparent structural and catalytic similarities of the enzyme from C. tepidum and its eukaryotic counterpart, the C. tepidum system should serve as an excellent model for studies of the enzymology and regulation of this protein. PMID:9244275

Wahlund, T M; Tabita, F R

1997-08-01

108

Redox titration of two [4Fe-4S] clusters in the photosynthetic reaction center from the anaerobic green sulfur bacterium Chlorobium vibrioforme.  

Science.gov (United States)

Anaerobic green sulfur bacteria contain photosynthetic reaction centers analogous to photosystem I (PS I) of plants and cyanobacteria. These reaction centers, termed type I, are characterized by the presence of bound iron-sulfur clusters as the terminal electron acceptors. In this work, the iron-sulfur clusters in Chlorobium vibrioforme were studied using selective light-induced reduction protocols, spin quantifications, and chemical redox titrations coupled with EPR detection. Illumination of a dark-frozen sample at 12 K results in the appearance of a spectrum termed signal I. Chemical reduction in darkness at solution potentials between -414 mV and -492 mV results in the appearance of a different spectrum termed signal II. Illumination of these chemically poised samples at 12 K results in the appearance of signal I such that the sum of the intensity of signal I + signal II is nearly constant for every ratio of signal I/signal II. As the solution potential is lowered to -545 mV, the spectrum shifts to yet a third set of resonances, termed signal III. Concomitant with this shift is a loss of low temperature light-induced reduction of signal I. Photoaccumulation of a sample poised at a solution potential of -50 mV results also in the appearance of signal III at nearly the same spin concentration as the chemically reduced sample. Spin quantifications imply that signals I and II are both derived from the reduction of one iron-sulfur cluster, termed center I; signal III is derived from simultaneous reduction of two iron-sulfur clusters, centers I and II. By measuring the EPR signal intensities over a range of solution potentials, centers I and II were shown to have Em (pH 10.0) values of -446 mV and -501 mV, respectively. The observations are consistent with a structural and functional analogy of centers I and II with F(A) and F(B) of PS I. PMID:9119012

Scott, M P; Kjoer, B; Scheller, H V; Golbeck, J H

1997-03-01

109

Selection of oleuropein-degrading lactic acid bacteria strains isolated from fermenting Moroccan green olives  

Energy Technology Data Exchange (ETDEWEB)

A total of 177 strains of lactic acid bacteria (LAB) were isolated from early-stage Moroccan Picholine green olive fermentation, including Lactobacillus plantarum (44.63%), Lactobacillus pentosus (25.99%), Lactobacillus brevis (9.61%) and Pediococcus pentosaceus (19.77%). All the isolates were screened for their tolerance to olive leaf extract and oleuropein. Most of the isolates (85.3%) were found able to degrade oleuropein, when evaluated by either oleuropein or 5-Bromo-4-chloro-3-indolyl {beta}-D-glucuronide (X-Gluc) as substrates. The biodegradation capacity of the selected strains of each species was confirmed by HPLC analysis. (Author).

Ghabbour, N.; Lamzira, Z.; Thonart, P.; Cidalia, P.; Markaouid, M.; Asehraoua, A.

2011-07-01

110

Characterization by Mass Spectroscopy of a 10 kDa c-554 Cytochrome from the Green Sulfur Bacterium Chlorobium tepidum.  

Science.gov (United States)

Preparative isoelectric focusing was used to isolate a type c cytochrome from photosynthetic membranes of the green sulfur bacterium Chlorobium tepidum. The purified protein showed a molecular weight of 10 kDa according to SDS-PAGE and ESI mass spectrometry. The absorption spectrum in the visible range is typical of a cytochrome with peaks at 420, 525.2 and 554.4 nm. Cleavage by either trypsin or endoproteinase lys-C of the isolated cytochrome combined with tandem mass spectrometry and Edman sequencing yielded a sequence perfectly matching parts of the recently sequenced genome of C. tepidum. PMID:16245046

Rémigy, Hervé-W; Aivaliotis, Michalis; Ioannidis, Nikos; Jenö, Paul; Mini, Thierry; Engel, Andreas; Jaquinod, Michel; Tsiotis, Georgios

2003-01-01

111

Rapid detection of bacteria in green tea using a novel pretreatment method in a bioluminescence assay.  

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Tea is one of the most popular beverages consumed in the world, and green tea has become a popular beverage in Western as well as Asian countries. A novel pretreatment method for a commercial bioluminescence assay to detect bacteria in green tea was developed and evaluated in this study. Pretreatment buffers with pH levels ranging from 6.0 to 9.0 were selected from MES (morpholineethanesulfonic acid), HEPES (N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid), or Tricine buffers. To evaluate the effect of pretreatment and the performance of the assay, serially diluted cultures of Enterobacter cloacae, Escherichia coli, Bacillus subtilis, and Staphylococcus aureus were tested. The improved methods, which consisted of a pretreatment of the sample in alkaline buffer, significantly decreased the background bioluminescence intensity of green tea samples when compared with the conventional method. Pretreatment with alkaline buffers with pH levels ranging from 8.0 to 9.0 increased the bioluminescence intensities of cultures of E. cloacae and S. aureus. Strong log-linear relationships between the bioluminescence intensities and plate counts emerged for the tested strains. Furthermore, the microbial detection limit was 15 CFU in 500 ml of bottled green tea after an 8-h incubation at 35°C and an assay time of 1 h. The results showed that contaminated samples could be detected within 1 h of operation using our improved bioluminescence assay. This method could be used to test for contamination during the manufacturing process as well as for statistical sampling for quality control. PMID:24853516

Shinozaki, Yohei; Harada, Yasuhiro

2014-06-01

112

Iron minerals formed by dissimilatory iron-and sulfur reducing bacteria studied by Moessbauer spectrometry  

International Nuclear Information System (INIS)

Zero-field and in-field Moessbauer investigations and electron paramagnetic resonance (EPR) measurements to follow the kinetics of the iron mineral formation by thermophilic dissimilatory anaerobic Fe(III)-reducing bacteria (strain Z-0001) and anaerobic alkaliphilic bacteria (strain Z-0531) were carried out.

2008-02-01

113

Iron minerals formed by dissimilatory iron-and sulfur reducing bacteria studied by Mössbauer spectrometry  

Science.gov (United States)

Zero-field and in-field Mössbauer investigations and electron paramagnetic resonance (EPR) measurements to follow the kinetics of the iron mineral formation by thermophilic dissimilatory anaerobic Fe(III)-reducing bacteria (strain Z-0001) and anaerobic alkaliphilic bacteria (strain Z-0531) were carried out.

Chistyakova, N. I.; Rusakov, V. S.; Nazarova, K. A.; Koksharov, Yu. A.; Zavarzina, D. G.; Greneche, J.-M.

2008-02-01

114

Green Synthesis and Characterization of Silver Nanoparticles for Antimicrobial Activity Against Burn Wounds Contaminating Bacteria  

Science.gov (United States)

Silver nanoparticles (AgNPs) were prepared from the plant extract of N. arbor-tristis under atmospheric conditions through green synthesis and characterized by various physicochemical techniques like UV-Visible spectroscopy, IR Spectra, energy dispersive X-ray spectrometry (EDS), X-ray diffraction and transmission electron microscopy (TEM) and the results confirmed the synthesis of homogeneous and stable AgNPs by the plant extracts. The antimicrobial activity of AgNPs was investigated against most common bacteria found in burn wound Staphylococcus epidermidis and Pseudomonas aeruginosa. In these tests, Mueller Hinton agar plates were used with AgNPs of various concentrations, supplemented in liquid systems. P. aeruginosa was inhibited at the low concentration of AgNPs, whereas the growth-inhibitory effect on S. epidermidis was mild. These results suggest that AgNPs can be used as effective growth inhibitors of various microorganisms, making them applicable to diverse medical devices and antimicrobial control systems.

Rout, Anandini; Jena, Padan K.; Sahoo, Debasish; Parida, Umesh K.; Bindhani, Birendra K.

2014-04-01

115

Characterization of lactic acid bacteria from naturally-fermented Manzanilla Aloreña green table olives.  

Science.gov (United States)

Manzanilla Aloreña (or Aloreña) table olives are naturally fermented traditional green olives with a denomination of protection (DOP). The aim of this study was to search for lactic acid bacteria (LAB) with technological properties of interest for possible inclusion in a starter or protective culture preparation or also as probiotics. A collection of 144 LAB obtained from Aloreña green table olives naturally-fermented by four small-medium enterprises (SMEs) from Málaga (Spain), including lactobacilli (81.94%), leuconostocs (10.42%) and pediococci (7.64%) were studied. REP-PCR clustering and further identification of strains by sequencing of phes and rpo genes revealed that all lactobacilli from the different SMEs were Lactobacillus pentosus. Pediococci were identified as Pediococcus parvulus (SME1) and leuconostocs as Leuconostoc pseudomesenteroides (SME1 and SME4). Genotyping revealed that strains were not clonally related and exhibited a considerable degree of genomic diversity specially for lactobacilli and also for leuconostocs. Some strains exhibit useful technological properties such as production of antimicrobial substances active against pathogenic bacteria such as Listeria monocytogenes, Bacillus cereus, Staphylococcus aureus, Streptococcus mutans and Salmonella enterica, utilization of raffinose and stachyose, production of bile salt hydrolase, phytase and haeme-dependent catalase activities, growth at 10 °C and in the presence of 6.5% NaCl, good acidifying capacity and also resistance to freezing. However, none of the isolates showed protease or amylase activity, and also did not exhibit biogenic amine production from histidine, ornithine, cysteine or tyrosine. On the basis of data obtained, selected strains with potential traits were tested for their survival at low pH and their tolerance to bile salts, and the survival capacity demonstrated by some of the analysed strains are encouraging to further study their potential as probiotics. PMID:22986194

Abriouel, Hikmate; Benomar, Nabil; Cobo, Antonio; Caballero, Natacha; Fernández Fuentes, Miguel Ángel; Pérez-Pulido, Rubén; Gálvez, Antonio

2012-12-01

116

A genomic region required for phototrophic thiosulfate oxidation in the green sulfur bacterium Chlorobium tepidum (syn. Chlorobaculum tepidum).  

Science.gov (United States)

The specific enzymes employed by Chlorobium tepidum for the anaerobic oxidation of thiosulfate, sulfide and elemental sulfur during anoxygenic photosynthesis are not well defined. In particular, it is unclear how C. tepidum completely oxidizes thiosulfate. A C. tepidum genomic region, encoding a putative quinone-interacting membrane-bound oxidoreductase (Qmo) complex (CT0866-0868), hypothetical proteins (CT0869-0875) and a sulfide : quinone oxidoreductase (SQR) homologue (CT0876), was analysed for its role in anaerobic sulfur oxidation. Transcripts of genes encoding the Qmo complex, which is similar to archaeal heterodisulfide reductases, were detected by RT-PCR only while sulfide or elemental sulfur were being oxidized, whereas the SQR homologue and CT0872 were expressed during thiosulfate oxidation and into early stationary phase. A mutant of C. tepidum was obtained in which the region between CT0868 and CT0876 was replaced by a transposon insertion resulting in the truncation or deletion of nine genes. This strain, C5, was completely defective for growth on thiosulfate as the sole electron donor in C. tepidum, but only slightly defective for growth on sulfide or thiosulfate plus sulfide. Strain C5 did not oxidize thiosulfate and also displayed a defect in acetate assimilation under all growth conditions. A gene of unknown function, CT0872, deleted in strain C5 that is conserved in chemolithotrophic sulfur-oxidizing bacteria and archaea is the most likely candidate for the thiosulfate oxidation phenotype observed in this strain. The defect in acetate assimilation may be explained by deletion of CT0874, which encodes a homologue of 3-oxoacyl acyl carrier protein synthase. PMID:18310028

Chan, Leong-Keat; Weber, Timothy S; Morgan-Kiss, Rachael M; Hanson, Thomas E

2008-03-01

117

Close interspecies interactions between prokaryotes from sulfureous environments  

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Full Text Available Green sulfur bacteria are obligate photolithoautotrophs that require highly reducing conditions for growth and can utilize only a very limited number of carbon substrates. These bacteria thus inhabit a very narrow ecologic niche. However, several green sulfur bacteria have overcome the limits of immobility by entering into a symbiosis with motile Betaproteobacteria in a type of multicelllular association termed phototrophic consortia. One of these consortia, “Chlorochromatium aggregatum”, has recently been established as the first culturable model system to elucidate the molecular basis of this symbiotic interaction. It consists of 12-20 green sulfur bacteria epibionts surrounding a central, chemoheterotrophic betaproteobacterium in a highly ordered fashion. Recent genomic, transcriptomic, and proteomic studies of "C. aggregatum" and its epibiont provide insights into the molecular basis and the origin of the stable association between the two very distantly related bacteria. While numerous genes of central metabolic pathways are upregulated during and hence involved in the specific symbiosis, only a limited number of unique putative symbiosis genes have been detected in the epibiont. Green sulfur bacteria therefore are preadapted to a symbiotic lifestyle. The metabolic coupling between the bacterial partners appears to involve amino acids and highly specific ultrastructures at the contact sites between the cells. Similarly, the interaction in the equally well studied archaeal consortia consisting of Nanoarchaeum equitans and its host Ignicoccus hospitalis is based on the transfer of amino acids while lacking the highly specialized contact sites observed in phototrophic consortia.

JörgOvermann

2011-07-01

118

Biologically produced sulfur  

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Sulfur compound oxidizing bacteria produce sulfur as an intermediate in the oxidation of hydrogen sulfide to sulfate. Sulfur produced by these microorganisms can be stored in sulfur globules, located either inside or outside the cell. Excreted sulfur globules are colloidal particles which are stabilized against aggregation by electrostatic repulsion or steric stabilization. The formed elemental sulfur has some distinctly different properties as compared to normal inorganic sulfur. The density...

Kleinjan, W. E.; Keizer, A.; Janssen, A. J. H.

2003-01-01

119

Chemolithotrophic Bacteria in Copper Ores Leached at High Sulfuric Acid Concentration  

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Extensive bacterial growth was observed when copper sulfide ores were leached with 0.6 N sulfuric acid. The bacterial population developed in this condition was examined by characterization of the spacer regions between the 16S and 23S rRNA genetic loci obtained after PCR amplification of the DNA extracted from the leached ore. The spacers observed had the sizes found in strains of "Leptospirillum ferrooxidans" and Thiobacillus thiooxidans, except for a larger one, approximately 560 bp long, ...

Vasquez, M.; Espejo, R. T.

1997-01-01

120

Sewage sludge bioleaching by indigenous sulfur-oxidizing bacteria: effects of ratio of substrate dosage to solid content.  

Science.gov (United States)

The aim of this work was to study the effect of ratio of substrate dosage to solid content (Sd/SC) on sewage sludge bioleaching. The inocula--indigenous sulfur-oxidizing bacteria were enriched and cultured from the fresh activated sludge to a wastewater treatment plant. The results showed that Sd/SC significantly influenced the sludge bioleaching process. With increase in Sd/SC the sludge bioleaching was enhanced, which was represented by the acceleration of sludge acidification, oxidizing environment formation, and substrate (sulfur) utilization. Higher Sd/SC was more efficient to solubilize the heavy metals and total phosphorus (TP) than lower Sd/SC, while total nitrogen (TN) release was not influenced by Sd/SC. Zinc and copper were efficiently bioleached because of sludge acidification and sludge oxidation, but lead was bioleached with a low efficiency because of the formation of low soluble PbSO(4) precipitates. After bioleaching the biotoxicity of sewage sludge greatly reduced. PMID:18945613

Zhang, Panyue; Zhu, Yi; Zhang, Guangming; Zou, Sai; Zeng, Guangming; Wu, Zhen

2009-02-01

 
 
 
 
121

Existing and emerging technologies that exploit sulfur cycling bacteria in subsurface petroleum reservoir microbial communities (Invited)  

Science.gov (United States)

Fossil fuels remain by far our most important energy resources, providing around 90% of global primary energy supply. In the coming decadal transition between petroleum reliance and a more sustainable energy future we must increasingly view our vital petroleum reserves as microbial ecosystems that can be engineered to responsibly and creatively meet the energy needs of societies worldwide. In this way, the bioenergy agenda must interface with the traditional geoenergy industry and the challenges it faces. Bioengineering and deep biosphere geomicrobiology focus on the ecophysiology and biogeography of microorganisms in subsurface habitats including marine sediments and petroleum reservoirs. Understanding microbial communities in fossil fuel deposits will allow their distribution and catalytic potential to be exploited as geobiotechnologies that target known problem areas including sulfur cycle management related to biodesulfurization of heavy oils and reservoir souring control via nitrate injection, as well as promising emerging directions such as understanding subsurface geofluid dispersal vectors that could enable microbes to be used as bio-indicators in offshore oil and gas exploration. Results related to different research themes within contemporary petroleum geomicrobiology and bioengineering at Newcastle University will be presented with a focus on microorganisms involved in sulfur cycling that are commonly detected in different oil field microbial communities including mesophilic sulfide-oxidizing Epsilonproteobacteria and thermophilic sulfate-reducers belonging to the genus Desulfotomaculum.

Hubert, C. R.

2013-12-01

122

Cultivation of autotrophic ammonia-oxidizing archaea from marine sediments in coculture with sulfur-oxidizing bacteria.  

Science.gov (United States)

The role of ammonia-oxidizing archaea (AOA) in nitrogen cycling in marine sediments remains poorly characterized. In this study, we enriched and characterized AOA from marine sediments. Group I.1a crenarchaea closely related to those identified in marine sediments and "Candidatus Nitrosopumilus maritimus" (99.1 and 94.9% 16S rRNA and amoA gene sequence identities to the latter, respectively) were substantially enriched by coculture with sulfur-oxidizing bacteria (SOB). The selective enrichment of AOA over ammonia-oxidizing bacteria (AOB) is likely due to the reduced oxygen levels caused by the rapid initial growth of SOB. After biweekly transfers for ca. 20 months, archaeal cells became the dominant prokaryotes (>80%), based on quantitative PCR and fluorescence in situ hybridization analysis. The increase of archaeal 16S rRNA gene copy numbers was coincident with the amount of ammonia oxidized, and expression of the archaeal amoA gene was observed during ammonia oxidation. Bacterial amoA genes were not detected in the enrichment culture. The affinities of these AOA to oxygen and ammonia were substantially higher than those of AOB. [(13)C]bicarbonate incorporation and the presence and activation of genes of the 3-hydroxypropionate/4-hydroxybutyrate cycle indicated autotrophy during ammonia oxidation. In the enrichment culture, ammonium was oxidized to nitrite by the AOA and subsequently to nitrate by Nitrospina-like bacteria. Our experiments suggest that AOA may be important nitrifiers in low-oxygen environments, such as oxygen-minimum zones and marine sediments. PMID:20870784

Park, Byoung-Joon; Park, Soo-Je; Yoon, Dae-No; Schouten, Stefan; Sinninghe Damsté, Jaap S; Rhee, Sung-Keun

2010-11-01

123

Green Tea Catechins Quench the Fluorescence of Bacteria-Conjugated Alexa Fluor Dyes  

Science.gov (United States)

Accumulating evidence suggests that Green tea polyphenolic catechins, especially the (-)-epigallocatechin gallate (EGCG), can be cross-linked to many proteins, and confer a wide range of anti-bacterial activities possibly by damaging microbial cytoplasmic lipids and proteins. At the doses that conferred protection against lethal polymicrobial infection (induced by cecal ligation and puncture), EGCG significantly reduced bacterial loads particularly in the liver and lung. To elucidate its bactericidal mechanisms, we determined whether EGCG affected the fluorescence intensities of bacteria-conjugated Alexa Fluor 488 or 594 dyes. When mixed with unconjugated Alexa Fluor 488 or 594 dyes, EGCG or analogs did not affect the fluorescence intensity of these dyes. In a sharp contrast, EGCG and some analogs (e.g., Catechin Gallate, CG), markedly reduced the fluorescence intensity of Gram-positive Staphylococcus aureus-conjugated Alexa 594 and Gram-negative Escherichia coli-conjugated Alexa 488. Interestingly, co-treatment with ethanol impaired the EGCG-mediated fluorescence quenching of the G+ S. aureus, but not of the G- E. coli-conjugated Alexa Flour dyes. In light of the notion that Alexa Fluor dyes can be quenched by aromatic amino acids, it is plausible that EGCG exerts anti-microbial activities possibly by altering microbial protein conformations and functions. This possibility can now be explored by screening other fluorescence-quenching agents for possible antimicrobial activities.

Zhao, Lin; Li, Wei; Zhu, Shu; Tsai, Sheena; Li, Jianhua; Tracey, Kevin J.; Wang, Ping; Fan, Saijun; Sama, Andrew E.; Wang, Haichao

2013-01-01

124

Characterization of isocitrate dehydrogenase from the green sulfur bacterium Chlorobium limicola. A carbon dioxide-fixing enzyme in the reductive tricarboxylic acid cycle.  

Science.gov (United States)

Isocitrate dehydrogenase (IDH) catalyzes the reversible conversion between isocitrate and 2-oxoglutarate accompanied by decarboxylation/carboxylation and oxidoreduction of NAD(P)+ cofactor. While this enzyme has been well studied as a catabolic enzyme in the tricarboxylic acid (TCA) cycle, here we have characterized NADP-dependent IDH from Chlorobium limicola, a green sulfur bacterium that fixes CO2 through the reductive tricarboxylic acid (RTCA) cycle, focusing on the CO2-fixation ability of the enzyme. The gene encoding Cl-IDH consisted of 2226 bp, corresponding to a polypeptide of 742 amino acid residues. The primary structure and the size of the recombinant protein indicated that Cl-IDH was a monomeric enzyme of 80 kDa distinct from the dimeric NADP-dependent IDHs predominantly found in bacteria or eukaryotic mitochondria. Apparent Michaelis constants for isocitrate (45 +/- 13 microm) and NADP+ (27 +/- 10 microm) were much smaller than those for 2-oxoglutarate (1.1 +/- 0.5 mm) and CO2 (1.3 +/- 0.3 mm). No significant differences in kinetic properties were observed between Cl-IDH and the dimeric, NADP-dependent IDH from Saccharomyces cerevisiae (Sc-IDH) at the optimum pH of each enzyme. However, in contrast to the 20% activity of Sc-IDH toward carboxylation as compared with that toward decarboxylation at pH 7.0, the activities of Cl-IDH for both directions were almost equivalent at this pH, suggesting a more favorable property of Cl-IDH than Sc-IDH as a CO2-fixation enzyme under physiological pH. Furthermore, we found that among various intermediates, oxaloacetate was a competitive inhibitor (K(i) = 0.35 +/- 0.04 mm) for 2-oxoglutarate in the carboxylation reaction by Cl-IDH, a feature not found in Sc-IDH. PMID:11952794

Kanao, Tadayoshi; Kawamura, Mineko; Fukui, Toshiaki; Atomi, Haruyuki; Imanaka, Tadayuki

2002-04-01

125

Structure and organization of a 25 kbp region of the genome of the photosynthetic green sulfur bacterium Chlorobium vibrioforme containing Mg-chelatase encoding genes.  

Science.gov (United States)

A region comprising approximately 25 kbp of the genome of the strictly anaerobic and obligate photosynthetic green sulfur bacterium Chlorobium vibrioforme has been mapped, subcloned and partly sequenced. Approximately 15 kbp have been sequenced in it's entirety and three genes with significant homology and feature similarity to the bchI, -D and -H genes and the chlI, -D and -H genes of Rhodobacter and Synechocystis strain PCC6803, respectively, which encode magnesium chelatase subunits, have been identified. Magnesium chelatase catalyzes the insertion of Mg2+ into protoporphyrin IX, and is the first enzyme unique to the (bacterio)chlorophyll specific branch of the porphyrin biosynthetic pathway. The organization of the three Mg-chelatase encoding genes is unique to Chlorobium and suggests that the magnesium chelatase of C. vibrioforme is encoded by a single operon. The analyzed 25 kbp region contains five additional open reading frames, two of which display significant homology and feature similarity to genes encoding lipoamide dehydrogenase and genes with function in purine synthesis, and another three display significant homology to open reading frames with unknown function in distantly related bacteria. Putative E. coli sigma 70-like promoter sequences, ribosome binding sequences and rho-independent transcriptional stop signals within the sequenced 15 kbp region are related to the identified genes and orfs. Southern analysis, restriction mapping and partial sequencing of the remaining ca. 10 kbp of the analyzed 25 kbp region have shown that this part includes the hemA, -C, -D and -B genes (MOBERG and AVISSAR 1994), which encode enzymes with function in the early part of the biosynthetic pathway of porphyrins. PMID:10022081

Petersen, B L; Møller, M G; Stummann, B M; Henningsen, K W

1998-01-01

126

Screening of antagonistic bacteria against the green mold disease (Trichoderma harzianum Rifai of Grey Oyster Mushroom (Pleurotus pulmonarius (Fr. Quel.  

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Full Text Available A total of 174 strains of bacteria antagonistic against the green mold (Trichoderma harzianum, isolated from cultivating bags and fruiting bodies of the mushrooms, were screened for effects on mushroom mycelia and ability to control the green mold disease. Twenty-eight of them promoted the primodia formation of the Pleurotus pulmonarius mycelia on agar plates. Twenty-two isolates were selected and further tested in a mushroom house. Cell suspension of each isolate was prepared and sprayed onto the spawn surface of P. pulmonarius. Fifteen isolates shortened the times required from watering to 2nd and 3rd flushing and increased yield of the basidiocarps by 1.1-34.3% over 30 days. Six isolates of bacteria which showed an inhibitory effect against T. harzianum, enhanced primordia formation and increased yield of P. pulmonarius were selected and used for control testing in a cultivation house. The suspension of each isolate was sprayed onto the spawn surface immediately after exposure to the air in the mushroom house, followed by spore suspension of T. harzianum two days later. The number of infected bags was counted at 30 days after inoculation and the cumulative yield was compared after 60 days. The results showed that bacteria isolate B012-022 was highly effective in suppressing the green mold disease.Only 6.7% of the cultivating bags were found to be infected by T. harzianum when bacteria isolate B012-022 was applied. Cumulative yield obtained from 900 g of 94% sawdust + 5% rice bran + 1% Ca(OH2 was 300.0 g/bag after 60 days, 71.1% higher than the bags infected by the green mold and without bacterial spraying. Identification of the six bacterial isolates showed all to be Bacillus spp.

Nualsri, C.

2005-01-01

127

Effectiveness of the bran media and bacteria inoculum treatments in increasing pH and reducing sulfur-total of acid sulfate soils  

Science.gov (United States)

This study was carried out to determine the effectiveness ofsulfate reducing bacteria (SRB) in using bran as a source of food and energy, and to see the effectiveness of the bran media and bacteria inoculums treatments for pH and sulfur-total of acid sulfate reduction insoils. This study used two factors in group random designs with four treatments for bacteria inoculum of B1 (1%), B2 (5%), B3 (10%), B4 (15%) and two treatments for organic media (bran) of D1 (1:1) and D2 (1:19). Based on three replications, the combination resulted in a total of 24 treatments. Soil pH was measured using the Duddridge and Wainright method and determination of sulfate content in soil was conducted by the spectrophotometry method. The data obtained was analyzed for significance by Analysis of Variance and the Least Significant Difference Test. The pH of the initial acid sulfate soils ranged from 3 to 4 and the soil sulfur-total ranged from 1.4% to 10%. After mixing sulfate reducing bacteria with the bran mediaand incubated for four days, the pH of the acid sulfate soils increased from 3.67 to 4.20, while the soil sulfur-total contents had been reduced by 2.85% to 0.35%. This experiment has proven that an acid sulfate soil with low pH is a good growth medium for the sulfate reducing bacteria. The bestincubation period to achieve an effective bioremediation resultthrough sulfate percentage reduction by sulfate reducing bacteria was 10 days, while the optimum bran media dose was 1:19, and the bacteria inoculums dose was 10%.

Taufieq, Nur Anny Suryaningsih; Rahim, Sahibin Abdul; Jamil, Habibah

2013-11-01

128

Filamentous sulfur bacteria, Beggiatoa spp., in arctic marine sediments (Svalbard, 79°N)  

DEFF Research Database (Denmark)

Fjord sediments on the west coast of the arctic archipelago Svalbard were surveyed to understand whether large filamentous sulfur bacteria of the genus Beggiatoa thrive at seawater temperatures permanently near freezing. Two sediments had abundant populations of Beggiatoa, while at six sites, only sporadic occurrences were observed. We conclude that Beggiatoa, although previously unnoticed, are widespread in these arctic fjord sediments. Beggiatoa ranged in diameter from 2 to 52 μm and, by those tested, stored nitrate in vacuoles at up to 260 mM. The 16S rRNA gene sequence of a 20-μm-wide filament is closely associated with other large, marine, nitrate-storing Beggiatoa. The Beggiatoa mostly occurred in the upper 2-5 cm of oxidized surface sediment between oxygen and the deeper sulfidic zone. In spite of a very low or an undetectable sulfide concentration, sulfate reduction provided abundant H2S in this zone. The total living biomass of Beggiatoa filaments at one study site varied over 3 years between 1.13 and 3.36 g m-2. Because of their large size, Beggiatoa accounted for up to 15% of the total prokaryotic biomass, even though the filament counts at this site were rather low, comprising <1/10 000 of the bacterial numbers on a cell basis.

Jørgensen, Bo Barker; Dunker, Rita

2010-01-01

129

The reaction center complex from the green sulfur bacterium Chlorobium tepidum: a structural analysis by scanning transmission electron microscopy.  

Science.gov (United States)

The three-dimensional (3D) structure of the reaction center (RC) complex isolated from the green sulfur bacterium Chlorobium tepidum was determined from projections of negatively stained preparations by angular reconstitution. The purified complex contained the PscA, PscC, PscB, PscD subunits and the Fenna-Matthews-Olson (FMO) protein. Its mass was found to be 454 kDa by scanning transmission electron microscopy (STEM), indicating the presence of two copies of the PscA subunit, one copy of the PscB and PscD subunits, three FMO proteins and at least one copy of the PscC subunit. An additional mass peak at 183 kDa suggested that FMO trimers copurify with the RC complexes. Images of negatively stained RC complexes were recorded by STEM and aligned and classified by multivariate statistical analysis. Averages of the major classes indicated that different morphologies of the elongated particles (length=19 nm, width=8 nm) resulted from a rotation around the long axis. The 3D map reconstructed from these projections allowed visualization of the RC complex associated with one FMO trimer. A second FMO trimer could be correspondingly accommodated to yield a symmetric complex, a structure observed in a small number of side views and proposed to be the intact form of the RC complex. PMID:10398586

Rémigy, H W; Stahlberg, H; Fotiadis, D; Müller, S A; Wolpensinger, B; Engel, A; Hauska, G; Tsiotis, G

1999-07-23

130

An isolated reaction center complex from the green sulfur bacterium Chlorobium vibrioforme can photoreduce ferredoxin at high rates.  

Science.gov (United States)

Chlorosome-depleted membranes and a reaction center complex with well-defined subunit composition were prepared from the green sulfur bacterium Chlorobium vibrioforme under anaerobic conditions. The reaction center complex contains a 15-kDa polypeptide with the N-terminal amino acid sequence MEPQLSRPETASNQVR/. This sequence is nearly identical to the N-terminus of the pscD gene product from Chlorobium limicola (Hager-Braun et al. (1995) Biochemistry 34: 9617-9624). In the presence of ferredoxin and ferredoxin:NADP(+) oxidoreductase, the membranes and the isolated reaction center complex photoreduced NADP(+) at rates of 333 and 110 ?mol (mg bacteriochlorophyll a)(-1) h(-1), respectively. This shows that the isolated reaction center complex contains all the components essential for steady state electron transport. Midpoint potentials at pH 7.0 of 160 mV for cytochrome c 551 and of 245 mV for P840 were determined by redox titration. Antibodies against cytochrome c 551 inhibit NADP(+) reduction while antibodies against the bacteriochlorophyll a-binding Fenna-Matthews-Olson protein do not. PMID:24301705

Kjær, B; Scheller, H V

1996-01-01

131

Thioalkalivibrio thiocyanoxidans sp. nov. and Thioalkalivibrio paradoxus sp. nov., novel alkaliphilic, obligately autotrophic, sulfur-oxidizing bacteria capable of growth on thiocyanate, from soda lakes.  

Science.gov (United States)

Nine strains of haloalkaliphilic, obligately autotrophic, sulfur-oxidizing bacteria able to grow with thiocyanate (SCN-) as the sole energy and nitrogen source were isolated from soda lakes in South-East Siberia, Kenya and Egypt after enrichment on sodium carbonate minerals buffered at pH 10 with thiocyanate as the substrate. The isolates fell into two groups that were substantially different in terms of cell morphology, growth parameters and the ability to oxidize carbon disulfide. The bacteria were able to oxidize sulfide, polysulfide, sulfur and tetrathionate, as well as thiocyanate. Two isolates belonged to an extremely halotolerant type growing in the presence of up to 4 M Na+. Cyanate (CNO-) was the main nitrogen-containing intermediate during thiocyanate degradation in both groups. According to DNA-DNA hybridization data and phylogenetic analysis, both groups of isolates belong to a recently described genus of haloalkaliphilic sulfur-oxidizing bacteria, i.e. Thioalkalivibrio, belonging to the gamma-Proteobacteria, in which where they represent two new species. The species name Thioalkalivibrio paradoxus (type strain ARh 1T = DSM 13531T = JCM 11367T) is proposed for the group with barrel-shaped cells, and the species name Thioalkalivibrio thiocyanoxidans (type strain ARh 2T, DSM 13532T = JCM 11368T) is proposed for the group with vibrio-shaped cells. The diagnosis of the genus Thioalkalivibrio is amended according to the new data. PMID:11931180

Sorokin, Dimitry Yu; Tourova, Tatyana P; Lysenko, Anatoly M; Mityushina, Lubov L; Kuenen, J Gijs

2002-03-01

132

Ultrafast energy transfer in light-harvesting chlorosomes from the green sulfur bacterium Chlorobium tepidum  

Science.gov (United States)

Two independent pump-probe techniques were used to study the antenna energy transfer kinetics of intact chlorosomes from the green bacterium Chlorobium tepidum with femtosecond resolution. The isotropic kinetics revealed by one-color experiments in the BChl c antenna were inhomogeneous with respect to wavelength. Multiexponential analyses of the photobleaching/stimulated emission (PB/SE) decay profiles typically yielded (apart from a ?10 fs component that may stem from the initial coherent oscillation) components with lifetimes 1-2 ps and several tens of ps. The largest amplitudes for the latter component occur at 810 nm, the longest wavelength studied. Analyses of most two-color pump-probe profiles with the probe wavelength red-shifted from the pump wavelength yielded no PB/SE rise components. PB/SE components with ? 1 ps risetime were found in 790 ? 810 and 790 ? 820 nm profiles, in which the probe wavelength is situated well into the BChl a absorption region. A 760 ? 740 nm uphill two-color experiment yielded a PB/SE component with 4-6 ps risetime. Broadband absorption difference spectra of chlorosomes excited at 720 nm (in the blue edge of the 746 nm BChl c Q y band) exhibit ?15 nm red-shifting of the PB/SE peak wavelength during the first several hundred fs. Analogous spectra excited at 760 nm (at the red edge) show little dynamic spectral shifting. Our results suggest that inhomogeneous broadening and spectral equilibration play a larger role in the early BChl c antenna kinetics in chlorosomes from C. tepidum than in those from C. aurantiacus, a system studied previously. As in C. aurantiacus, the initial one-color anisotropies r(0) for most BChl c wavelengths are close t0 0.4. The corresponding residual anisotropies r(?) are typically 0.19-0.25, which is much lower than found in C. aurantiacus (>/0.35); the transition moment organization is appreciably less collinear in the BChl c antenna of C. tepidum. However, the final one-color anisotropies at 789 and 801 nm are ? 0 and 0.09 respectively, and the final anisotropy in the 780 ? 800 nm experiment is ? -0.1. These facts indicate that the BChl a transition moments themselves exhibit some order, and are directed at an angle >54.7° on the average from the BChl c moments. The one-color profiles exhibit coherent oscillations at most wavelengths, including 800 nm; Fourier analyses of these oscillations frequently yield components with frequencies 70-80 and 130-140 cm -1.

Savikhin, Sergei; van Noort, Paula I.; Zhu, Yinwen; Lin, Su; Blankenship, Robert E.; Struve, Walter S.

1995-05-01

133

Preliminary investigations of hydrogen peroxide treatment of selected ornamental fishes and efficacy against external bacteria and parasites in green swordtails.  

Science.gov (United States)

The objectives of these preliminary studies were to evaluate the use of hydrogen peroxide (H2O2) for the treatment of selected species of ornamental fishes and its efficacy in treating external bacteria and parasites. In the first part of the study, fish of five species (serpae tetra Hyphessobrycon eques (also known as Serpa tetra H. serpae), tiger barb Puntius tetrazona, blue gourami Trichogaster trichopterus, suckermouth catfish Hypostomus plecostomus, and green swordtail Xiphophorus hellerii) were exposed to H2O2 for 1 h at concentrations between 6 and 34 mg/L or for 24 h at concentrations between 1 and 6 mg/L. The results were species specific: green swordtails tolerated all of the treatments, serpae tetras and tiger barbs were sensitive only to the highest concentration, and mortalities of suckermouth catfish and blue gourami were recorded in every treatment. In the second part of the study, clinically healthy green swordtails and fish infested with external motile rod-shaped bacteria (i.e., Ichthyobodo spp., Trichodina spp., and Gyrodactylus spp.) were treated with several concentrations of H2O2. A single H2O2 treatment of 3.1 mg/L or more for 1 h effectively eliminated external bacteria, concentrations of 6.5 mg/L or more appeared to effectively kill Ichthyobodo spp., and none of the treatments tested was effective against Trichodina spp. or Gyrodactylus spp. These preliminary findings suggest that H2O2 is effective for treating certain external bacterial infections and flagellate infestations in some species of ornamental fish at the dosages tested. Other treatment regimens may need to be tested for effectiveness against Trichodina spp. and Dactylogyrus spp. PMID:18201053

Russo, Riccardo; Curtis, Eric W; Yanong, Roy P E

2007-06-01

134

Function of a PscD subunit in a homodimeric reaction center complex of the photosynthetic green sulfur bacterium Chlorobium tepidum studied by insertional gene inactivation. Regulation of energy transfer and ferredoxin-mediated NADP+ reduction on the cytoplasmic side.  

Science.gov (United States)

The PscD subunit in the homodimeric "type I" photosynthetic reaction center (RC) complex of the green sulfur bacterium Chlorobium tepidum was disrupted by insertional mutagenesis of its relevant pscD gene. This is the first report on the use of the direct mutagenic approach into the RC-related genes in green sulfur bacteria. The RC complex of C. tepidum is supposed to form a homodimer of two identical PscA subunits together with three other subunits: PscB (FA/FB-containing protein), PscC (cytochrome cz), and PscD. PscD shows a relatively low but significant similarity in its amino acid sequence to PsaD in the photosystem I of plants and cyanobacteria. We studied the biochemical and spectroscopic properties of a mutant lacking PscD in order to elucidate its unknown function. 1) The RC complex isolated from the mutant cells showed no band corresponding to PscD on SDS-PAGE analysis. 2) The growth rate of the PscD-less mutant was slower than that of the wild-type cells at low light intensities. 3) Time-resolved fluorescence spectra at 77 K revealed prolonged decay times of the fluorescence from bacteriochlorophyll c on the antenna chlorosome and from bacteriochlorophyll a on the Fenna-Matthews-Olson antenna protein in the mutant cells. The loss of PscD led to a much slower energy transfer from the antenna pigments to the special pair bacteriochlorophyll a (P840). 4) The mutant strain exhibited slightly less activity of ferredoxin-mediated NADP+ photoreduction compared with that in the wild-type strain. The extent of suppression, however, was less significant than that reported in the PsaD-less mutants of cyanobacterial photosystem I. The evolutionary relationship between PscD and PsaD was also discussed based on a structural homology modeling of the former. PMID:15371432

Tsukatani, Yusuke; Miyamoto, Ryo; Itoh, Shigeru; Oh-Oka, Hirozo

2004-12-01

135

Antibiotic Resistant Bacteria As Bio-Indicator Of Polluted Effluent In The Green Turtles, Chelonia Mydas In Oman  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Antibiotic resistant bacteria were studied as bio-indicators of marine polluted effluents during egg-laying in green turtles. A non-invasive procedure for sampling oviductal fluid was used to test for exposure of turtles to pollution in Ras Al-Hadd, Oman, which is one of the most important nesting beaches in the world. Each sample was obtained by inserting a 15 cm sterile swab gently into the cloacal vent as the sphincter muscle is relaxed and the cloacal lining is unfolde...

2011-01-01

136

Rubredoxin from the green sulfur bacterium Chlorobium tepidum functions as an electron acceptor for pyruvate ferredoxin oxidoreductase.  

Science.gov (United States)

Rubredoxin (Rd) from the moderately thermophilic green sulfur bacterium Chlorobium tepidum was found to function as an electron acceptor for pyruvate ferredoxin oxidoreductase (PFOR). This enzyme, which catalyzes the conversion of pyruvate to acetyl-CoA and CO(2), exhibited an absolute dependence upon the presence of Rd. However, Rd was incapable of participating in the pyruvate synthase or CO(2) fixation reaction of C. tepidum PFOR, for which two different reduced ferredoxins are employed as electron donors. These results suggest a specific functional role for Rd in pyruvate oxidation and provide the initial indication that the two important physiological reactions catalyzed by PFOR/pyruvate synthase are dependent on different electron carriers in the cell. The UV-visible spectrum of oxidized Rd, with a monomer molecular weight of 6500, gave a molar absorption coefficient at 492 nm of 6.89 mM(-1) cm(-1) with an A(492)/A(280) ratio of 0.343 and contained one iron atom/molecule. Further spectroscopic studies indicated that the CD spectrum of oxidized C. tepidum Rd exhibited a unique absorption maximum at 385 nm and a shoulder at 420 nm. The EPR spectrum of oxidized Rd also exhibited unusual anisotropic resonances at g = 9.675 and g = 4.322, which is composed of a narrow central feature with broader shoulders to high and low field. The midpoint reduction potential of C. tepidum Rd was determined to be -87 mV, which is the most electronegative value reported for Rd from any source. PMID:10514453

Yoon, K S; Hille, R; Hemann, C; Tabita, F R

1999-10-15

137

green  

Directory of Open Access Journals (Sweden)

Full Text Available The “green” topic follows the “youngsters”, which is quite natural for the Russian language.Traditionally these words put together sound slightly derogatory. However, “green” also means fresh, new and healthy.For Russia, and for Siberia in particular, “green” architecture does sound new and fresh. Forced by the anxious reality, we are addressing this topic intentionally. The ecological crisis, growing energy prices, water, air and food deficits… Alexander Rappaport, our regular author, writes: “ It has been tolerable until a certain time, but under transition to the global civilization, as the nature is destroyed, and swellings of megapolises expand incredibly fast, the size and the significance of all these problems may grow a hundredfold”.However, for this very severe Siberian reality the newness of “green” architecture may turn out to be well-forgotten old. A traditional Siberian house used to be built on principles of saving and environmental friendliness– one could not survive in Siberia otherwise.Probably, in our turbulent times, it is high time to fasten “green belts”. But we should keep from enthusiastic sticking of popular green labels or repainting of signboards into green color. We should avoid being drowned in paper formalities under “green” slogans. And we should prevent the Earth from turning into the planet “Kin-dza-dza”.

Elena Grigoryeva

2011-02-01

138

Membrane proteome of the green sulfur bacterium Chlorobium tepidum (syn. Chlorobaculum tepidum) analyzed by gel-based and gel-free methods.  

Science.gov (United States)

Chlorobium tepidum is a Gram-negative bacterium of the green sulfur phylum (Chlorobia). Chlorobia are obligate anaerobic photolithoautotrophs that are widely distributed in aquatic environments where anoxic layers containing reduced sulfur compounds are exposed to light. The envelope of C. tepidum is a complex organelle composed of the outer membrane, the periplasm-peptidoglycan layer, and the cytoplasmic membrane. In addition to the outer and plasma membranes, C. tepidum contains chlorosomes attached to the cytoplasmic side of the plasma membrane. Each cellular compartment has a unique set of proteins, called sub-proteome. An important aim of proteome analysis is to study the level of the expressed genes and their response to environmental changes. Membrane protein studies are of primary importance to understand how nutrients are transported inside the cell, how toxic molecules are exported, and the mechanisms of photosynthesis and energy metabolism. PMID:20349210

Kouyianou, Kalliopi; Aivaliotis, Michalis; Gevaert, Kris; Karas, Michael; Tsiotis, Georgios

2010-06-01

139

Gene inactivation in the cyanobacterium Synechococcus sp. PCC 7002 and the green sulfur bacterium Chlorobium tepidum using in vitro-made DNA constructs and natural transformation.  

Science.gov (United States)

Inactivation of a chromosomal gene is a useful approach to study the function of the gene in question and can be used to produce a desired phenotype in the organism. This chapter describes how to generate such mutants of the cyanobacterium Synechococcus sp. PCC 7002 and the green sulfur bacterium Chlorobium tepidum by natural transformation with synthetic DNA constructs. Two alternative methods to generate the DNA constructs, both performed entirely in vitro and based on the polymerase chain reaction (PCR), are also presented. These methods are ligation of DNA fragments with T4 DNA ligase, and megaprimer PCR. PMID:15187290

Frigaard, Niels-Ulrik; Sakuragi, Yumiko; Bryant, Donald A

2004-01-01

140

Utility of Green Fluorescent Nucleic Acid Dyes and Aluminum Oxide Membrane Filters for Rapid Epifluorescence Enumeration of Soil and Sediment Bacteria  

Digital Repository Infrastructure Vision for European Research (DRIVER)

High background fluorescence and unspecific staining hampered the epifluorescence enumeration of bacteria in 45% of the tested soil and sediment samples with 4?,6-diamidino-2-phenylindole (DAPI) and polycarbonate membrane filters. These problems of the determination of total cell counts can be circumvented by using green fluorescent high-affinity nucleic acid dyes and aluminum oxide membrane filters. Due to the bright staining of cells, we recommend SYBR Green II as dye.

Weinbauer, Markus G.; Beckmann, Christiane; Ho?fle, Manfred G.

1998-01-01

 
 
 
 
141

Utility of green fluorescent nucleic acid dyes and aluminum oxide membrane filters for rapid epifluorescence enumeration of soil and sediment bacteria.  

Science.gov (United States)

High background fluorescence and unspecific staining hampered the epifluorescence enumeration of bacteria in 45% of the tested soil and sediment samples with 4',6-diamidino-2-phenylindole (DAPI) and polycarbonate membrane filters. These problems of the determination of total cell counts can be circumvented by using green fluorescent high-affinity nucleic acid dyes and aluminum oxide membrane filters. Due to the bright staining of cells, we recommend SYBR Green II as dye. PMID:9835595

Weinbauer, M G; Beckmann, C; Höfle, M G

1998-12-01

142

Fe-S cluster biogenesis in Gram-positive bacteria: SufU is a zinc-dependent sulfur transfer protein.  

Science.gov (United States)

The biosynthesis of Fe-S clusters in Bacillus subtilis and other Gram-positive bacteria is catalyzed by the SufCDSUB system. The first step in this pathway involves the sulfur mobilization from the free amino acid cysteine to a sulfur acceptor protein SufU via a PLP-dependent cysteine desulfurase SufS. In this reaction scheme, the formation of an enzyme S-covalent intermediate is followed by the binding of SufU. This event leads to the second half of the reaction where a deprotonated thiol of SufU promotes the nucleophilic attack onto the persulfide intermediate of SufS. Kinetic analysis combined with spectroscopic methods identified that the presence of a zinc atom tightly bound to SufU (Ka = 10(17) M(-1)) is crucial for its structural and catalytic competency. Fe-S cluster assembly experiments showed that despite the high degree of sequence and structural similarity to the ortholog enzyme IscU, the B. subtilis SufU does not act as a standard Fe-S cluster scaffold protein. The involvement of SufU as a dedicated agent of sulfur transfer, rather than as an assembly scaffold, in the biogenesis of Fe-S clusters in Gram-positive microbes indicates distinct strategies used by bacterial systems to assemble Fe-S clusters. PMID:24321018

Selbach, Bruna P; Chung, Alexander H; Scott, Aubrey D; George, Simon J; Cramer, Stephen P; Dos Santos, Patricia C

2014-01-14

143

Menaquinone-7 in the reaction center complex of the green sulfur bacterium Chlorobium vibrioforme functions as the electron acceptor A1.  

Science.gov (United States)

Photosynthetically active reaction center complexes were prepared from the green sulfur bacterium Chlorobium vibrioforme NCIMB 8327, and the content of quinones was determined by extraction and high-performance liquid chromatography. The analysis showed a stoichiometry of 1.7 molecules of menaquinone-7/reaction center. No other quinones were detected in the isolated reaction centers, whereas membrane preparations also contained chlorobiumquinone. The possible involvement of quinones in electron transport was investigated by electron paramagnetic resonance (EPR) spectroscopy. A highly anisotropic radical was detected by Q-band EPR spectroscopy in both membranes and isolated reaction centers following dark reduction with sodium dithionite and photoaccumulation at 205 K. At 34 GHz, the EPR spectrum is characterized by a g tensor with gxx = 2.0063, gyy = 2.0052, gzz = 2.0020 and delta B of 0.7 mT, consistent with its identification as a quinone. This spectrum is highly similar in terms of g values and line widths to photoaccumulated A1- in photosystem I of Synechococcus sp. PCC 7002. The results indicate that menaquinone-7 in the green sulfur bacterial reaction center is analogous to phylloquinone in photosystem I. PMID:9536963

Kjaer, B; Frigaard, N U; Yang, F; Zybailov, B; Miller, M; Golbeck, J H; Scheller, H V

1998-03-10

144

Formation of Fe(III)-containing mackinawite from hydroxysulphate green rust by sulphate reducing bacteria  

International Nuclear Information System (INIS)

The interactions between Fe(II-III) hydroxysulphate GR(SO42-) and sulphate reducing bacteria (SRB) were studied. The considered SRB, Desulfovibrio desulfuricans subsp. aestuarii ATCC 29578, were added with GR(SO42-) to culture media. Different conditions were envisioned, corresponding to various concentrations of bacteria, various sources of sulphate (dissolved SO42- + GR(SO42-) or GR(SO42-) alone) and various atmospheres (N2:H2 or N2:CO2:H2). In the first part of the study, CO2 was deliberately omitted so as to avoid the formation of carbonated compounds, and GR(SO42-) was the only source of sulphate. Cell concentration increases from ?4 x 107 to ?7 x 108 cells/mL in 2 weeks. The evolution with time of the iron compounds, monitored by Raman spectroscopy and X-ray diffraction, showed the progressive formation of a FeS compound, the Fe(III)-containing mackinawite. This result is consistent with the association GR(SO42-)/SRB/FeS observed in rust layers formed on steel in seawater. In the presence of CO2 and additional dissolved sulphate species, a rapid growth of the bacteria could be observed, leading to the total transformation of GR(SO42-) into mackinawite, found in three physico-chemical states (nanocrystalline, crystalline stoichiometric FeS and Fe(III)-containing), and siderite FeCO3.

2009-11-01

145

Use of Green Fluorescent Protein To Tag and Investigate Gene Expression in Marine Bacteria  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Two broad-host-range vectors previously constructed for use in soil bacteria (A. G. Matthysse, S. Stretton, C. Dandie, N. C. McClure, and A. E. Goodman, FEMS Microbiol. Lett. 145:87–94, 1996) were assessed by epifluorescence microscopy for use in tagging three marine bacterial species. Expression of gfp could be visualized in Vibrio sp. strain S141 cells at uniform levels of intensity from either the lac or the npt-2 promoter, whereas expression of gfp could be visualized in Psychrobacter s...

Stretton, Serina; Techkarnjanaruk, Somkiet; Mclennan, Alan M.; Goodman, Amanda E.

1998-01-01

146

Development of a gas diffusion multicommuted flow injection system for the determination of sulfur dioxide in wines, comparing malachite green and pararosaniline chemistries.  

Science.gov (United States)

A flow system based on the multicommutation concept was developed for the determination of free and total sulfur dioxide in table wines, exploiting gas diffusion separation and spectrophotometric detection. The system allowed the comparison of malachite green and pararosaniline chemistries, using the same manifold configuration. Free and total SO(2) were determined within the ranges 1.00-40.0 and 25.0-250 mg L(-1), at determination throughputs of 25 and 23 h(-1), respectively. Employing the malachite green reaction, detection limits of 0.3 and 0.8 mg L(-1) were attained for free and total SO(2), respectively. Pararosaniline chemistry provided detection limits of 0.6 mg L(-1) for free SO(2) and 0.8 mg L(-1) for total SO(2). Relative standard deviations better than 1.8 and 1.4% were obtained by the malachite green and pararosaniline reactions, respectively. With regard to the two tested chemistries, 18 wines were analyzed and the results achieved by the pararosaniline reaction compared better with those furnished by the recommended procedure. PMID:19309149

Oliveira, Sara M; Lopes, Teresa I M S; Tóth, Ildikó V; Rangel, António O S S

2009-05-13

147

Seawater-based methane production from blue-green algae biomass by marine bacteria coculture  

Energy Technology Data Exchange (ETDEWEB)

Marine-enriched culture NKM 004 produced methane from various carbohydrates, but methane production was inhibited by sulfate and acetate accumulated in the medium. On the other hand, marine methanogenic bacterium NKM 006 produced methane from acetate and methyltrophic substrates, and methane production was not inhibited by sulfate. The mixture of NKM 004 and NKM 006 continuously produced methane from marine blue-green algae Dermocarpa species NKBG 102B at 54 ..mu..mol/L medium/h for 200 h and the dry weight of the algal biomass was decreased to 25% of the initial weight in the natural seawater. Conversion of algal carbohydrate (glucose equivalent) to methane was 65%. Results indicate that this system is promising for methane production based on seawater and solar energy.

Matsunaga, T.; Izumida, H.

1984-01-01

148

Microbiological study of naturally fermented Algerian green olives: isolation and identification of lactic acid bacteria and yeasts along with the effects of brine solutions obtained at the end of olive fermentation on Lactobacillus plantarum...  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The microflora of naturally fermented green olives produced in Western Algeria was studied over 15, 60 and 90 day fermentation periods. Different microorganisms (aerobic bacteria, coliforms, staphylococci, lactic acid bacteria, lactobacilli, enterococci, yeasts, psychrotrophs and lipolytic bacteria) were recorded at 15 and 60 days of fermentation. After 90 days (pH 4.40) of fermentation, the lactic acid bacte...

Mourad, Kacem; Nour-eddine, Karam

2006-01-01

149

Antioxidant efficacy of crude methanol extract of ashitaba green tea against radiation induced oxidative stress in E.coli K12 bacteria  

International Nuclear Information System (INIS)

This study was undertaken to evaluate the antioxidant activity of methanol crude extract of ashitaba green tea (G). The DPPH scavenging assay was evaluated for green tea extract to determine its radical scavenging capacity. The bacteria was pretreated with ashitaba green tea extract, quercetin (Q) and (-) epigallocatechin -3-gallate (E) at below MIC level. Oxidative stress was induced at 0.4 Gy using gamma radiation. The antioxidant efficacy of ashitaba green tea was evaluated through enzyme antioxidant studies like SOD (Superoxidedismutase) and CAT (Catalase). The oxidative stress marker Thiobarbituric acid-reactive substance (TBARS) was also evaluated. Further the protective efficacy of the(G) was confirmed by colony forming units (CFU) study. Among the tested compounds the crude extract of ashitaba (G) exhibited excellent antioxidant activity in comparison with quercetin and (-) epigallocatechin -3-gallate. (abstract)

2013-03-20

150

Different sensitivities to oxygen between two strains of the photosynthetic green sulfur bacterium Chlorobium vibrioforme NCIB 8327 with bacteriochlorophyll c and d.  

Science.gov (United States)

Two sub-strains of the anoxygenic photosynthetic green sulfur bacterium Chlorobium vibrioforme NCIB 8327 were derived from the same clone and could be discriminated only by their possession of either bacteriochlorophyll (BChl) c or d as the major pigment in the peripheral light-harvesting antenna system, chlorosome (Saga Y et al. (2003) Anal Sci 19: 1575-1579). In the presence of a proper amount of oxygen in the initial culture medium, the BChl d strain showed longer retardation on its growth initiation than the BChl c strain, indicating that the latter was advantageous for survival under aerobic light conditions which produced reactive oxygen species in vivo. The result would be ascribable to the difference of the midpoint potentials between two kinds of chlorosomes formed by self-aggregates of BChl c and d as measured by their fluorescence quenching. PMID:16172933

Harada, Jiro; Saga, Yoshitaka; Oh-oka, Hirozo; Tamiaki, Hitoshi

2005-11-01

151

Kinetics of electron transfer between soluble cytochrome c-554 and purified reaction center complex from the green sulfur bacterium Chlorobium tepidum.  

Science.gov (United States)

Soluble cytochrome c-554 (M (r) approximately 10 kDa) is purified from the green sulfur bacterium Chlorobium tepidum. Its midpoint redox potential is determined to be +148 mV from redox titration at pH 7.0. The kinetics of cytochrome c-554 oxidation by a purified reaction center complex from the same organism were studied by flash absorption spectroscopy at room temperature, and the results indicate that the reaction partner of cytochrome c-554 is cytochrome c-551 bound to the reaction center rather than the primary donor P840. The second-order rate constant for the electron donation from cytochrome c-554 to cytochrome c-551 was estimated to be 1.7x10(7) M(-1) s(-1). The reaction rate was not significantly influenced by the ionic strength of the reaction medium. PMID:16228506

Itoh, Masaaki; Seo, Daisuke; Sakurai, Hidehiro; Sétif, Pierre

2002-01-01

152

Application of indigenous sulfur-oxidizing bacteria from municipal wastewater to selectively bioleach phosphorus from high-phosphorus iron ore: effect of particle size.  

Science.gov (United States)

The effects of ore particle size on selectively bioleaching phosphorus (P) from high-phosphorus iron ore were studied. The average contents of P and Fe in the iron ore were 1.06 and 47.90% (w/w), respectively. The particle sizes of the ores used ranged from 58 to 3350 microm. It was found that the indigenous sulfur-oxidizing bacteria from municipal wastewater could grow well in the slurries of solid high-phosphorus iron ore and municipal wastewater. The minimum bioleaching pH reached for the current work was 0.33. The P content in bioleached iron ore reduced slightly with decreasing particle size, while the removal percentage of Fe decreased appreciably with decreasing particle size. The optimal particle size fraction was 58-75 microm, because the P content in bioleached iron ore reached a minimum of 0.16% (w/w), the removal percentage of P attained a maximum of 86.7%, while the removal percentage of Fe dropped to a minimum of 1.3% and the Fe content in bioleached iron ore was a maximum of 56.4% (w/w) in this case. The iron ores thus obtained were suitable to be used in the iron-making process. The removal percentage of ore solid decreased with decreasing particle size at particle size range of 106-3350 microm. The possible reasons resulting in above phenomena were explored in the current work. It was inferred that the particle sizes of the iron ore used in this work have no significant effect on the viability of the sulfur-oxidizing bacteria. PMID:23530328

Shen, Shaobo; Rao, Ruirui; Wang, Jincao

2013-01-01

153

Assessing acute toxicity of effluent from a textile industry and nearby river waters using sulfur-oxidizing bacteria in continuous mode.  

Science.gov (United States)

Bioassays are becoming an important tool for assessing the toxicity of complex mixtures of substances in aquatic environments in which Daphnia magna is routinely used as a test organism. Bioassays outweigh physicochemical analyses and are valuable in the decision-making process pertaining to the final discharge of effluents from wastewater treatment plants as they measure the total effect of the discharge which is ecologically relevant. In this study, the aquatic toxicity of a textile plant effluent and river water downstream from the plant were evaluated with sulfur-oxidizing bacterial biosensors in continuous mode. Collected samples were analysed for different physicochemical parameters and 1,4-dioxane was detected in the effluent. The effluent contained a relatively high chemical oxygen demand of 60 mg L(-1), which exceeded the limit set by the Korean government for industrial effluent discharges. Results showed that both the effluent and river waters were toxic to sulfur-oxidizing bacteria. These results show the importance of incorporating bioassays to detect toxicity in wastewater effluents for the sustainable management of water resources. PMID:22329151

Gurung, Anup; Hassan, Sedky H A; Oh, Sang-Eun

2011-10-01

154

CO2 assimilation in the chemocline of Lake Cadagno is dominated by a few types of phototrophic purple sulfur bacteria  

DEFF Research Database (Denmark)

Lake Cadagno is characterized by a compact chemocline that harbors high concentrations of various phototrophic sulfur bacteria. Four strains representing the numerically most abundant populations in the chemocline were tested in dialysis bags in situ for their ability to fix COâ??. The purple sulfur bacterium Candidatus 'Thiodictyon syntrophicum' strain Cad16(T) had the highest COâ?? assimilation rate in the light of the four strains tested and had a high COâ?? assimilation rate even in the dark. The COâ?? assimilation of the population represented by strain Cad16(T) was estimated to be up to 25% of the total primary production in the chemocline. Pure cultures of strain Cad16(T) exposed to cycles of 12 h of light and 12 h of darkness exhibited the highest COâ?? assimilation during the first 4 h of light. The draft genome sequence of Cad16(T) showed the presence of cbbL and cbbM genes, which encode form I and form II of RuBisCO, respectively. Transcription analyses confirmed that, whereas cbbM remained poorly expressed throughout light and dark exposure, cbbL expression varied during the light-dark cycle and was affected by the available carbon sources. Interestingly, the peaks in cbbL expression did not correlate with the peaks in COâ?? assimilation.

Storelli, Nicola; Peduzzi, Sandro

2013-01-01

155

CO2 assimilation in the chemocline of Lake Cadagno is dominated by a few types of phototrophic purple sulfur bacteria.  

DEFF Research Database (Denmark)

Lake Cadagno is characterized by a compact chemocline that harbors high concentrations of various phototrophic sulfur bacteria. Four strains representing the numerically most abundant populations in the chemocline were tested in dialysis bags in situ for their ability to fix COâ??. The purple sulfur bacterium Candidatus 'Thiodictyon syntrophicum' strain Cad16(T) had the highest COâ?? assimilation rate in the light of the four strains tested and had a high COâ?? assimilation rate even in the dark. The COâ?? assimilation of the population represented by strain Cad16(T) was estimated to be up to 25% of the total primary production in the chemocline. Pure cultures of strain Cad16(T) exposed to cycles of 12 h of light and 12 h of darkness exhibited the highest COâ?? assimilation during the first 4 h of light. The draft genome sequence of Cad16(T) showed the presence of cbbL and cbbM genes, which encode form I and form II of RuBisCO, respectively. Transcription analyses confirmed that, whereas cbbM remained poorly expressed throughout light and dark exposure, cbbL expression varied during the light-dark cycle and was affected by the available carbon sources. Interestingly, the peaks in cbbL expression did not correlate with the peaks in COâ?? assimilation.

Storelli, Nicola; Peduzzi, Sandro

2013-01-01

156

Time-resolved step-scan FTIR investigation on the primary donor of the reaction center from the green sulfur bacterium Chlorobium tepidum.  

Science.gov (United States)

The vibrational properties of the primary donor P(840) in the reaction center (RC) of the green sulfur bacterium Chlorobium tepidum and its interactions with the surrounding protein environment have been investigated by Fourier transform infrared (FTIR) difference spectroscopy at cryogenic temperatures. By using the step-scan technique with a time resolution of 5 mus on RCs that had been depleted of the iron-sulfur electron acceptors, the formation and decay of the triplet state (3)P(840) have been followed in infrared for the first time. The (3)P(840)/P(840) FTIR difference spectrum is compared to the P(840) (+)/P(840) FTIR difference spectrum measured under identical conditions on untreated RCs and recorded with the same step-scan set-up. The latter P(840) (+)/P(840) difference spectrum is essentially the same as those measured under steady-state conditions using the more conventional continuous illumination method. Comparison of the (3)P(840)/P(840) and P(840) (+)/P(840) spectra provides unambiguous assignment of the vibration of the 9-keto C=O group(s) of P(840) at 1684 cm(-1) as the only common negative band in the two spectra. This frequency corresponds to carbonyl group(s) free from hydrogen bonding interactions. The obtained results are discussed in the framework of the structure and photochemistry of the primary donor P(840). PMID:16245086

Mezzetti, Alberto; Seo, Daisuke; Leibl, Winfried; Sakurai, Hidehiro; Breton, Jacques

2003-01-01

157

AKTIVITAS ANTIBAKTERI FRAKSI-FRAKSI EKSTRAK SIRIH HIJAU (Piper betle Linn TERHADAP PATOGEN PANGAN [Antibacterial Activity of Fractionated Green Sirih (Piper betle Linn Extract Against Food Pathogenic Bacteria  

Directory of Open Access Journals (Sweden)

Full Text Available Fractionation of green sirih (Piper betle Linn extract by chromatography colom using the mixture of several solvents i.e. chloroform, ethanol and acetic acid (4:1:1 resulted in 17 fractions. All fractions showed antibacterial activities but only 2 fractions (fraction 3 and fraction 4 showed the highest inhibition towards the six tested bacteria Escherichia coli, Salmonella Typhimurium, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus and Listeria monocytogenes. Among the tested bacteria, all fractions of green sirih extracts showed the most effective inhibition against, Salmonella Typhimurium with inhibition zone diameters ranging from 10 mm to 26 mm. Identification using GC-MS found that fraction 3 and fraction 4 contained chavicol; dodecanoic acid, myristic, palmitic and oleic acid.

Maggy T. Suhartono

2012-12-01

158

Diel Variations in Carbon Metabolism by Green Nonsulfur-Like Bacteria in Alkaline Siliceous Hot Spring Microbial Mats from Yellowstone National Park  

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Green nonsulfur-like bacteria (GNSLB) in hot spring microbial mats are thought to be mainly photoheterotrophic, using cyanobacterial metabolites as carbon sources. However, the stable carbon isotopic composition of typical Chloroflexus and Roseiflexus lipids suggests photoautotrophic metabolism of GNSLB. One possible explanation for this apparent discrepancy might be that GNSLB fix inorganic carbon only during certain times of the day. In order to study temporal variability in carbon metaboli...

Meer, Marcel T. J.; Schouten, Stefan; Bateson, Mary M.; Nu?bel, Ulrich; Wieland, Andrea; Ku?hl, Michael; Leeuw, Jan W.; Sinninghe Damste?, Jaap S.; Ward, David M.

2005-01-01

159

AKTIVITAS ANTIBAKTERI FRAKSI-FRAKSI EKSTRAK SIRIH HIJAU (Piper betle Linn) TERHADAP PATOGEN PANGAN [Antibacterial Activity of Fractionated Green Sirih (Piper betle Linn) Extract Against Food Pathogenic Bacteria  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Fractionation of green sirih (Piper betle Linn) extract by chromatography colom using the mixture of several solvents i.e. chloroform, ethanol and acetic acid (4:1:1) resulted in 17 fractions. All fractions showed antibacterial activities but only 2 fractions (fraction 3 and fraction 4) showed the highest inhibition towards the six tested bacteria Escherichia coli, Salmonella Typhimurium, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus and Listeria monocytogenes. Among the test...

2012-01-01

160

Comparison of bamboo green, timber and yellow in sulfite, sulfuric acid and sodium hydroxide pretreatments for enzymatic saccharification.  

Science.gov (United States)

The response and behavior of bamboo green, timber, and yellow of moso bamboo (Phyllostachys heterocycla) to three pretreatments, sulfite (SPORL), dilute acid (DA), and alkali (NaOH), were investigated and compared with varied chemical loadings at 180°C for 30 min with a 6.25:1 (v/w) liquor-to-bamboo ratio. All the pretreatments improved the enzymatic digestibility of bamboo substrates. Under the investigated conditions, the DA pretreatment achieved better enzymatic digestibility, but had lower sugar recovery yield, and formed more fermentation inhibitors. The results suggested that the SPORL pretreatment be able to generate more readily digestible bamboo substrate with higher sugar yield and fewer fermentation inhibitors than the corresponding DA pretreatment if hemicelluloses are sufficiently removed by adding more acid to bring down the pretreatment pH. Bamboo timber had higher sugar content and better enzymatic digestibility and therefore was a better feedstock for bioconversion than bamboo green and yellow. PMID:24212128

Li, Zhiqiang; Jiang, Zehui; Fei, Benhua; Cai, Zhiyong; Pan, Xuejun

2014-01-01

 
 
 
 
161

Reconstitution of an active magnesium chelatase enzyme complex from the bchI, -D, and -H gene products of the green sulfur bacterium Chlorobium vibrioforme expressed in Escherichia coli.  

Science.gov (United States)

Magnesium-protoporphyrin chelatase, the first enzyme unique to the (bacterio)chlorophyll-specific branch of the porphyrin biosynthetic pathway, catalyzes the insertion of Mg2+ into protoporphyrin IX. Three genes, designated bchI, -D, and -H, from the strictly anaerobic and obligately phototrophic green sulfur bacterium Chlorobium vibrioforme show a significant level of homology to the magnesium chelatase-encoding genes bchI, -D, and -H and chlI, -D, and -H of Rhodobacter sphaeroides and Synechocystis strain PCC6803, respectively. These three genes were expressed in Escherichia coli; the subsequent purification of overproduced BchI and -H proteins on an Ni2+-agarose affinity column and denaturation of insoluble BchD protein in 6 M urea were required for reconstitution of Mg-chelatase activity in vitro. This work therefore establishes that the magnesium chelatase of C. vibrioforme is similar to the magnesium chelatases of the distantly related bacteria R. sphaeroides and Synechocystis strain PCC6803 with respect to number of subunits and ATP requirement. In addition, reconstitution of an active heterologous magnesium chelatase enzyme complex was obtained by combining the C. vibrioforme BchI and -D proteins and the Synechocystis strain PCC6803 ChlH protein. Furthermore, two versions, with respect to the N-terminal start of the bchI gene product, were expressed in E. coli, yielding ca. 38- and ca. 42-kDa versions of the BchI protein, both of which proved to be active. Western blot analysis of these proteins indicated that two forms of BchI, corresponding to the 38- and the 42-kDa expressed proteins, are also present in C. vibrioforme. PMID:9457877

Petersen, B L; Jensen, P E; Gibson, L C; Stummann, B M; Hunter, C N; Henningsen, K W

1998-02-01

162

Viscosity dependence of the electron transfer rate from bound cytochrome c to P840 in the photosynthetic reaction center of the green sulfur bacterium Chlorobium tepidum.  

Science.gov (United States)

Anomalous high viscosity dependence was found in the rate of reaction between the bound cytochrome c and the primary donor bacteriochlorophyll dimer (P840) of the reaction center complex purified from the green sulfur bacterium Chlorobium tepidum. The cytochrome has a primary structure with the N-terminal three membrane-spanning helices connected to the extended C-terminal heme-containing hydrophilic moiety. The rate constant of the reaction decreased from 5.0 x 10(3) s-1 to 1.0 x 10 s-1 as the glycerol concentration increased from 0 to 60% (v/v) at 295 K, showing a linear dependence on the -2.4th power of the specific viscosity. The glycerol effect was fully reversible. The extraordinary high viscosity dependence cannot be explained by the simple diffusive Brownian fluctuation model and suggests that the electron transfer mechanism is dependent on the unique conformational fluctuations of the heme-containing moiety of cytochrome c. PMID:9230061

Oh-oka, H; Iwaki, M; Itoh, S

1997-07-29

163

Purification of water polluted with oil and sulfurous closed-ring and aromatic compounds contained in oil and oil products using bacteria relating to thiosphaera  

Energy Technology Data Exchange (ETDEWEB)

The intensity of natural purification (self-purification) of reservoirs polluted with oil and oil products is determined by microorganisms. Hydrocarbon-oxidizing microorganisms are constant natural constituent of biocenose in reservoirs. However, as a result of outflows, the oil and oil products concentration exceeds maximum values allowing normal vital functions of microorganisms resulting in breaking micro-biocenose suppression of vital functions of bacteria. In this regard, elective anaerobic microorganisms of Thiosphaera are worthy of notice. We found out that bacteria belonging to Thiosphaera pantotropha decomposed oil at high oil concentrations in water (at oil concentration like 1 liter of oil in 1 liter of water). And this is when aerobic microorganisms lose their vital functions at maximum concentration of 20 g of oil in 1 liter of water. To intensify the process of oil decomposition we emulsified oil with aqueous solutions of salts. Thiosphaera pantotropha are found out to decompose oil in a wide range of ratio between oil and aqueous solutions of salts: from 1:10 to 10:1. The water solutions salinity made from 20 g/l to 80 g/l. It must be noticed that, since the Thiosphaera pantotropha are elective anaerobes and decompose oil both in presence and in absence of oxygen, it is not necessary anymore to conduct the process under strictly anaerobic conditions and to supply additional oxygen. This makes it possible to simplify the process of biodegradation of oil and to make this process practically more feasible and economically more profitable being compared to the processes based on the use of other species of bacteria. We found out that Thiosphaera decompose sulfurous closed-ring and aromatic compounds in oil which are chemically and thermally stable and can be hardly decomposed, and possess extremely poisonous properties, as well. The use of microorganisms of Thiosphaera pantotropha allows to purify waters polluted with oil and oil products both during planned purification of old impurities and in cases of emergency, in cases of oil outflows. (authors)

Kurashov, V.M.; Sakhno, T.V. [Research and Production Centre, Ecological Consortium, Kazan (Russian Federation); Gavrilov, V.S. [Inspection of Nature Management in the Republic of Tatarstan, Directorate of Federal Dept., Kazan (Russian Federation); Zijatdinov, R.N. [Kazan State Academy of Veterinary Medicine (Russian Federation)

2005-07-01

164

Purification of water polluted with oil and sulfurous closed-ring and aromatic compounds contained in oil and oil products using bacteria relating to thiosphaera  

International Nuclear Information System (INIS)

The intensity of natural purification (self-purification) of reservoirs polluted with oil and oil products is determined by microorganisms. Hydrocarbon-oxidizing microorganisms are constant natural constituent of biocenose in reservoirs. However, as a result of outflows, the oil and oil products concentration exceeds maximum values allowing normal vital functions of microorganisms resulting in breaking micro-biocenose suppression of vital functions of bacteria. In this regard, elective anaerobic microorganisms of Thiosphaera are worthy of notice. We found out that bacteria belonging to Thiosphaera pantotropha decomposed oil at high oil concentrations in water (at oil concentration like 1 liter of oil in 1 liter of water). And this is when aerobic microorganisms lose their vital functions at maximum concentration of 20 g of oil in 1 liter of water. To intensify the process of oil decomposition we emulsified oil with aqueous solutions of salts. Thiosphaera pantotropha are found out to decompose oil in a wide range of ratio between oil and aqueous solutions of salts: from 1:10 to 10:1. The water solutions salinity made from 20 g/l to 80 g/l. It must be noticed that, since the Thiosphaera pantotropha are elective anaerobes and decompose oil both in presence and in absence of oxygen, it is not necessary anymore to conduct the process under strictly anaerobic conditions and to supply additional oxygen. This makes it possible to simplify the process of biodegradation of oil and to make this process practically more feasible and economically more profitable being compared to the processes based on the use of other species of bacteria. We found out that Thiosphaera decompose sulfurous closed-ring and aromatic compounds in oil which are chemically and thermally stable and can be hardly decomposed, and possess extremely poisonous properties, as well. The use of microorganisms of Thiosphaera pantotropha allows to purify waters polluted with oil and oil products both during planned purification of old impurities and in cases of emergency, in cases of oil outflows. (authors)

2005-10-03

165

Reconstitution of an Active Magnesium Chelatase Enzyme Complex from the bchI, -D, and -H Gene Products of the Green Sulfur Bacterium Chlorobium vibrioforme Expressed in Escherichia coli  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Magnesium-protoporphyrin chelatase, the first enzyme unique to the (bacterio)chlorophyll-specific branch of the porphyrin biosynthetic pathway, catalyzes the insertion of Mg2+ into protoporphyrin IX. Three genes, designated bchI, -D, and -H, from the strictly anaerobic and obligately phototrophic green sulfur bacterium Chlorobium vibrioforme show a significant level of homology to the magnesium chelatase-encoding genes bchI, -D, and -H and chlI, -D, and -H of Rhodobacter sphaeroides and Synec...

Petersen, Bent L.; Jensen, Poul Erik; Gibson, Lucien C. D.; Stummann, Bjarne M.; Hunter, C. Neil; Henningsen, Knud W.

1998-01-01

166

A multi-gene approach in the systematics of the phototrophic purple sulfur bacteria genera Marichromatium and Allochromatium with description of the new species Allochromatium humboldtianum and the new biotype Marichromatium gracile biotype thermosulfidiphilum.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the present thesis two genera of the photosynthetic Purple Sulfur Bacteria (PSB) of the family Chromatiaceae are revised by molecular techniques which include extensive DNA-DNA hybridization (DDH) studies and a multi-gene analysis. Traditionally, species of PSB have been described based on some easily recognizable phenotypic properties and separated in two families the Chromatiaceae and Ectothiorhosdopiraceae. Within the Chromatiaceae the genus Chromatium was also separated in several gene...

Serrano Wilbert

2009-01-01

167

Developing a Biofilm of Sulfur Oxidizing Bacteria, Starting-up and Operating a Bioscrubber Treating H2S  

Directory of Open Access Journals (Sweden)

Full Text Available Development of an acclimatized SOB biofilm, startup and performance of a fixed bed bioscrubber packed with corrugated tube parts as a media having high specific surface area was investigated. Bioscrubber was a cylindrical Plexiglas air-and water-tight column with 10 L in working bed volume. Sludge from a tannery wastewater treatment plant was used as a seed for SOB separation, acclimation and enrichment. Enriched acclimatized SOB were applied as inoculum for biofilm development, which was carried out by recirculating the prepared microbial suspension through the bed. Thickness of the developed biofilm was 56 ?m in which active acidophilic autotrophic H2S oxidizing bacteria were completely predominated. Activity measurements showed highest biodegradation rate of biofilm at liquid pH around 3. Due to employing an efficient specialized biofilm, startup period of the reactor was quite short and H2S removal efficiency just 12 h after starting up reached above of 92% and increased to 96% at day 3 of starting up while inlet H2S concentration gradually was increased to around 30 ppm. At the end of start up pH of the recycle liquid was modified to the optimal value of 3±0.5 in which biofilm demonstrated the highest activity in terms of OUR after which removal efficiency increased around 3% while other operating conditions were consistent. Furthermore, performance of the bioscrubber was evaluated at various inlet H2S concentrations ranging from 30 to 150 ppmv. It was indicated that the inlet H2S concentrations in studied range did not affect the performance of the bioscrubber so that the removal efficiency of H2S was greater than 99.4% at all concentrations. These observations suggested that the development of an efficient specialized SOB biofilm on a media with high specific surface area will decrease the startup course and achieve high removal efficiency in the bioscrubber treating H2S. In addition, operation in acidic recycle liquid will overcome use of alkaline to adjust the pH, which reduce the operation cost of the control system.

Gholamreza Moussavi

2007-01-01

168

Isolation and endotoxin activities of lipopolysaccharides from cyanobacterial cultures and complex water blooms and comparison with the effects of heterotrophic bacteria and green alga.  

Science.gov (United States)

Massive cyanobacterial water blooms are serious environmental and health problems worldwide. While some cyanobacterial toxins such as peptide microcystins have been investigated extensively, other toxic components of cyanobacteria (e.g. lipopolysaccharides, LPS) are poorly understood. The present study characterized endotoxin activities of LPS isolated from (i) laboratory cyanobacterial cultures, (ii) cyanobacterial water bloom samples dominated by Microcystis sp., Planktothrix sp., Aphanizomenon sp. and Anabaena sp., (iii) heterotrophic Gram-negative bacteria Escherichia coli, Kluyvera intermedia, Pseudomonas putida and Pseudomonas fluorescens and (iv) green alga Pseudokirchneriella subcapitata. Toxicity results derived with Limulus amebocyte lysate assay (LAL-test) showed that endotoxin activities of LPS from both cyanobacteria and heterotrophic bacteria were comparable and the values were within a similar range (1 x 10(3)-1 x 10(6) Endotoxin Units, EU, per mg of isolated LPS). The highest activities among the cyanobacterial samples were observed in the Aphanizomenon sp. dominated water bloom. The results also suggest generally higher endotoxin activities in complex natural samples than in laboratory cyanobacterial cultures. Further, experiments with the eukaryotic green alga P. subcapitata demonstrated a need for careful purification of the LPS extracts prior to testing with the LAL assay as several contaminants may overestimate endotoxin activities. This study shows relatively high pyrogenicity of LPS from various cyanobacteria. Further research should focus on detailed toxicological and ecotoxicological characterization of LPS in massive cyanobacterial water blooms. PMID:17461433

Bernardová, Katerina; Babica, Pavel; Marsálek, Blahoslav; Bláha, Ludek

2008-01-01

169

Effect of light quality on sulfide photo-oxidation and growth in an artificial biofilm of the green sulfur bacterium Prosthecochloris aestuarii.  

Science.gov (United States)

We have succeeded in culturing an axenic biofilm of the green sulfur bacterium Prosthecochloris aestuarii strain CE 2404 in an artificial sandy sediment under visible light (400-700 nm). This simulates the conditions of deep submerged sediments. A five-week incubation period, using a 16-hour light / 8-hour dark regime, was applied in the benthic gradient chamber (BGC). The biofilm was located below the oxygen penetration depth of 1.2 mm, namely between 1.5 and 2.5 mm and the biomass peak was at 2.1 mm depth. This is much shallower compared to previously described artificial mats of P. aestuarii, which were grown in the BGC under near infrared (NIR)-rich light. High resolution time courses of photosynthesis were measured as sulfide photo-oxidation rates and studied under visible light and visible light amended with NIR to assess the effect of light quality. Sulfide photo-oxidation rates were rather low under visible light and strongly stimulated at most depths under full light conditions. However, under the latter conditions the rates decelerated after a maximum rate was reached at 8-10 min, apparently due to diffusional limitation of sulfide supply. It was concluded that the top of the mat was not limited by the photon flux density, while the biomass peak and the bottom of the biofilm were severely light limited under the culture conditions. These results support the hypothesis that a biofilm of P. aestuarii can develop in deep submerged sediments, when the oxygen penetration depth is very shallow. Nevertheless, the addition of NIR light strongly enhances the potential of P. aestuarii to grow deeper in the sediment. PMID:16228511

Massé, Astrid; Pringault, Olivier; de Wit, Rutger

2002-01-01

170

Spectroscopic and functional properties of novel 2[4Fe-4S] cluster-containing ferredoxins from the green sulfur bacterium Chlorobium tepidum.  

Science.gov (United States)

Two distinct ferredoxins, Fd I and Fd II, were isolated and purified to homogeneity from photoautotrophically grown Chlorobium tepidum, a moderately thermophilic green sulfur bacterium that assimilates carbon dioxide by the reductive tricarboxylic acid cycle. Both ferredoxins serve a crucial role as electron donors for reductive carboxylation, catalyzed by a key enzyme of this pathway, pyruvate synthase/pyruvate ferredoxin oxidoreductase. The reduction potentials of Fd I and Fd II were determined by cyclic voltammetry to be -514 and -584 mV, respectively, which are more electronegative than any previously studied Fds in which two [4Fe-4S] clusters display a single transition. Further spectroscopic studies indicated that the CD spectrum of oxidized Fd I closely resembled that of Fd II; however, both spectra appeared to be unique relative to ferredoxins studied previously. Double integration of the EPR signal of the two Fds yielded approximately approximately 2.0 spins per molecule, compatible with the idea that C. tepidum Fd I and Fd II accept 2 electrons upon reduction. These results suggest that the C. tepidum Fd I and Fd II polypeptides each contain two bound [4Fe-4S] clusters. C. tepidum Fd I and Fd II are novel 2[4Fe-4S] Fds, which were shown previously to function as biological electron donors or acceptors for C. tepidum pyruvate synthase/pyruvate ferredoxin oxidoreductase (Yoon, K.-S., Hille, R., Hemann, C. F., and Tabita, F. R. (1999) J. Biol. Chem. 274, 29772-29778). Kinetic measurements indicated that Fd I had approximately 2.3-fold higher affinity than Fd II. The results of amino acid sequence alignments, molecular modeling, oxidation-reduction potentials, and spectral properties strongly indicate that the C. tepidum Fds are chimeras of both clostridial-type and chromatium-type Fds, suggesting that the two Fds are likely intermediates in the evolutional development of 2[4Fe-4S] clusters compared with the well described clostridial and chromatium types. PMID:11568186

Yoon, K S; Bobst, C; Hemann, C F; Hille, R; Tabita, F R

2001-11-23

171

ATP-citrate lyase from the green sulfur bacterium Chlorobium limicola is a heteromeric enzyme composed of two distinct gene products.  

Science.gov (United States)

The reductive tricarboxylic acid cycle functions as a carbon dioxide fixation pathway in the green sulfur bacterium, Chlorobium limicola. ATP-citrate lyase, one of the key enzymes of this cycle, was partially purified from C. limicola strain M1 and the N-terminal sequence of a 65-kDa protein was found to show similarity toward eukaryotic ATP-citrate lyase. A DNA fragment was amplified with primers designed from this sequence and an internal sequence highly conserved among eukaryotic enzymes. Using this fragment as a probe, we isolated a DNA fragment containing two adjacent open reading frames, aclB (1197 bp) and aclA (1827 bp), whose products showed significant similarity to the N- and C-terminal regions of the human enzyme, respectively. Heterologous expression of these genes in Escherichia coli showed that both gene products were essential for ATP-citrate lyase activity. The recombinant enzyme was purified from the cell-free extract of E. coli harboring aclBA for further characterization. The molecular mass of the recombinant enzyme was determined to be approximately 532--557 kDa by gel-filtration. The enzyme catalyzed the cleavage of citrate in an ATP(-), CoA- and Mg(2+)-dependent manner, where ATP and Mg(2+) could be replaced by dATP and Mn(2+), respectively. ADP and oxaloacetate inhibited the reaction. These properties suggested that ATP-citrate lyase from C. limicola controlled the cycle flux depending on intracellular energy conditions. This paper provides the first direct evidence that a bacterial ATP-citrate lyase is a heteromeric enzyme, distinct from mammalian enzymes. PMID:11248686

Kanao, T; Fukui, T; Atomi, H; Imanaka, T

2001-03-01

172

New carotenoids from the thermophilic green sulfur bacterium Chlorobium tepidum: 1',2'-dihydro-gamma-carotene, 1',2'-dihydrochlorobactene, and OH-chlorobactene glucoside ester, and the carotenoid composition of different strains.  

Science.gov (United States)

The complete carotenoid composition of the thermophilic green sulfur bacterium Chlorobium tepidum strain TNO was determined by spectroscopic methods. Major carotenoids were four kinds of carotenes: gamma-carotene, chlorobactene, and their 1',2'-dihydro derivatives (1',2'-dihydro-gamma-carotene and 1',2'-dihydrochlorobactene). In lesser amounts, hydroxyl gamma-carotene, hydroxyl chlorobactene, and their glucoside fatty acid esters were found. The only esterified fatty acid present was laurate, and OH-chlorobactene glucoside laurate is a novel carotenoid. In other strains of C. tepidum, the same carotenoids were found, but the composition varied from strain to strain. The overall pigment composition in cells of strain TNO was 4 mol carotenoids and 40 mol bacteriochlorophyll c per mol bacteriochlorophyll a. The effects of nicotine on carotenoid biosynthesis in C. tepidum differed from those in the thermophilic green nonsulfur bacterium Chloroflexus aurantiacus. PMID:9297463

Takaichi, S; Wang, Z Y; Umetsu, M; Nozawa, T; Shimada, K; Madigan, M T

1997-10-01

173

Sulfur as a Matrix for the Development of Microbial Biofilm Communities  

Science.gov (United States)

The high temperature, low oxygen, and high sulfide concentration of many hot springs select for a low diversity of organisms. The stringent requirements for growth and survival limit the types of interactions, which allow the microbial sulfur metabolism to be examined in depth. We combined geochemical, microbial and molecular data to understand mat development in the warm, oxygen-poor sulfidic Stinking Spring, Utah, USA. The upper flow zone of this spring has a variety of observable microbial biofilm structures that are linked to the activities of both sulfide-oxidizing and oxygenic bacteria. The diverse architecture of the microbial assemblages consist of bulbous ridge structures on the bottom of the streambed, floating mats that cover a large portion of the water surface area, and two morphologically different streamers; green long filaments and white shorter filaments, which both contain large amounts of elemental sulfur. We performed structural analysis using phase contrast and epifluorescence microscopy, and SEM coupled with EDS mapping. Amplicon sequenced 16S rRNA genes analyzed by QIIME and ARB indicated that the predominant organisms present were the cyanobacterial genus Leptolyngbya, and an ?-Proteobacteria closely related to the sulfur oxidizing genus Sulfurovum. Metagenomic analysis was conducted on six libraries from three locations using MG-RAST to analyze for genes associated with sulfur metabolism, specifically sulfur oxidation (sox) genes. The presence of sox genes and the microbial sulfur deposition strategy changes downstream as the sulfide concentration decreases. When sulfide is low, the streamers themselves become white and shorter with elemental sulfur deposited intracellularly, and diatoms seem to dominate over cyanobacteria, but do not form associations with the streamer structures. We propose that the microbial biofilms and green streamers present in the sulfide-rich section of the stream are formed in a multi-step process. Initial growth of cyanobacteria on bottom sulfur mats form green bulbous ridges that rise from the streambed by gas produced inside the mat. The bulbous features then break off and form floating mats. This is followed by colonization of remnant filaments by the proposed Sulfurovum. A repeating cycle ensues, in which the Sulfurovum produce a crust of elemental sulfur that the cyanobacteria must migrate past. This slowly builds up a core of elemental sulfur strings sheathed in cyanobacteria. Together, the co-habitation and interactions between sulfide-oxidizing bacteria and photosynthetic cyanobacteria construct visible physical structures that can potentially be preserved in the rock record.

Parker, C.; Bell, E.; Johnson, J. E.; Ma, X.; Stamps, B. W.; Rideout, J.; Johnson, H. A.; Vuono, D.; Spear, J. R.; Hanselmann, K.

2013-12-01

174

Characterization of Sulfur Compounds in Coffee Beans by Sulfur K-XANES Spectroscopy  

International Nuclear Information System (INIS)

In this 'feasibility study' the influence of roasting on the sulfur speciation in Mexican coffee beans was investigated by sulfur K-XANES Spectroscopy. Spectra of green and slightly roasted beans could be fitted to a linear combination of 'standard' reference spectra for biological samples, whereas longer roasting obviously involves formation of additional sulfur compounds in considerable amounts

2007-02-02

175

Safe use of genetically modified lactic acid bacteria in food: Bridging the gap between consumers, green groups, and industry  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english Within the European Union (EU), the use of genetically modified organisms (GMOs) in food production is not widely applied and accepted. In contrast to the United States of America, the current EU legislation limits the introduction of functional foods derived from GMOs that may bring a clear benefit [...] to the consumer. Genetically modified lactic acid bacteria (GM-LAB) can be considered as a different class of GMOs, and the European Union is preparing regulations for the risk assessment of genetically modified microorganisms. Since these procedures are not yet implemented, the current risk assessment procedure is shared for GMOs derived from micro organisms, plants, or animals. At present, the use of organisms in food production that have uncontrolled genetic alterations made through random mutagenesis, is permitted, while similar applications with organisms that have controlled genetic alterations are not allowed. The current paper reviews the opportunities that genetically modified lactic acid bacteria may offer the food industry and the consumer. An objective risk profile is described for the use of GM-LAB in food production. To enhance the introduction of functional foods with proven health claims it is proposed to adapt the current safety assessment procedures for (GM)-LAB and suggestions are made for the related cost accountability. A qualified presumption of safety as proposed by SANCO (EU SANCO 2003), based on taxonomy and on the history of safe use of LAB applied in food, could in the near future be applied to any kind of LAB or GM-LAB provided that a series of modern profiling methods are used to verify the absence of unintended effects of altered LAB that may cause harm to the health of the consumer.

Sybesma, Wilbert; Hugenholtz, Jeroen; de Vos, Willem M.; Smid, Eddy J..

176

Physico-Chemical and Microbial Quality of Locally Composted and Imported Green Waste Composts in Oman  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this work the physical, chemical and microbial properties of four locally composted green waste composts (GWCs) namely Almukhasib, Growers, Plantex, and Super along with four imported GWC (Florabella, Mikskaar, Potgrond, and Shamrock) were studied to evaluate the quality of these composts with the acceptable standards. All composts showed normal physical properties, except the bad smell from sulfur reducing bacteria in Almukhasib, light brown color Plantex and one viable weed seed in Shamr...

El-nagerabi, Saifeldin A. F.; Elshafie, Abdulkadir E.; Al-bahry, Saif N.; Alrawahi, Hasina S.; Huda AlBurashdi

2011-01-01

177

The effect of green tea extract on the removal of sulfur-containing oral malodor volatiles in vitro and its potential application in chewing gum.  

Science.gov (United States)

Increasing pH solution from 7.5 to 8.0 was found to significantly improve the effectiveness of green tea extract for methanethiol removal in vitro. Green tea extract was also found to remove hydrogen sulfide and its effectiveness was greatly improved under alkaline conditions. It was found that with green tea extract, maximum H?S removal was achieved when the pH was between 8.1 and 8.4 at 37 °C for 5 min. Further increases in pH resulted in decrease of the extract effectiveness. Vegetable acetone powders which contain polyphenol oxidases or peroxidases were found to further enhance the effectiveness for the removal of thiols when used in combination with green tea extracts at body temperature under alkaline conditions. Adding 5% baking soda to green tea extract-containing chewing gum was found to buffer saliva pHs to 8.0 during 10 min of chewing. However, severe discoloration was observed and undesirable bitterness was perceived, most likely due to the polymerization of unencapsulated green tea polyphenols. Therefore, encapsulation of green tea extract is recommended for applications at elevated pHs. PMID:21383482

Zeng, Q C; Wu, A Z; Pika, J

2010-09-01

178

Microbiological study of naturally fermented Algerian green olives: isolation and identification of lactic acid bacteria and yeasts along with the effects of brine solutions obtained at the end of olive fermentation on Lactobacillus plantarum...  

Directory of Open Access Journals (Sweden)

Full Text Available The microflora of naturally fermented green olives produced in Western Algeria was studied over 15, 60 and 90 day fermentation periods. Different microorganisms (aerobic bacteria, coliforms, staphylococci, lactic acid bacteria, lactobacilli, enterococci, yeasts, psychrotrophs and lipolytic bacteria were recorded at 15 and 60 days of fermentation. After 90 days (pH 4.40 of fermentation, the lactic acid bacteria population became dominant and persisted together with yeasts throughout the fermentation period. The lactic acid bacteria isolated (343 isolates were identified as L. casei, L. rhamnosus, L. paracasei, L. plantarum, L. lactis subsp. lactis, E. faecalis, E. faecium and E. durans. The dominant species was L. plantarum. Yeasts were isolated from all samples (32 isolates and were identified as Saccharomyces cerevisiae or Candida parapsilosis. Also, in this study we reported that brine solutions obtained at the end of olive fermentation were able to stimulate the growth of several L. plantarum strainsLa microflora de las aceitunas verdes fermentadas naturalmente elaboradas en Argelia Occidental fue estudiada en períodos de fermentación de 15, 60 y 90 días. Diferentes microorganismos (bacterias aeróbicas, coliformes, estafilococos, bacterias del ácido láctico, lactobacilos, enterococos, levaduras, psicotrofos y bacterias lipolíticas fueron detectados a los 15 y 60 días de fermentación. Después de 90 días de fermentación (pH 4.40, la población de bacterias lácticas se hizo dominante y persistió junto con las levaduras a lo largo de todo el proceso. Las bacterias lácticas aisladas (343 fueron identificadas como L. casei, L. rhamnosus, L. paracasei, L. plantarum, L. lactis subsp. lactis, E. faecalis, E. faecium y E. durans. La especie dominante fue L. plantarum. Las levaduras aisladas (32 de todas las muestras fueron identificadas como Saccharomyces cerevisiae o Candida parapsilosis. También se recoge en este estudio que las soluciones de salmuera obtenidas al final de fermentación de aceitunas verdes fueron capaces de estimular el crecimiento de varias cepas de L. plantarum.

Nour-Eddine, Karam

2006-09-01

179

Isolation and structural determination of C8-vinyl-bacteriochlorophyll d from the bciA and bchU double mutant of the green sulfur bacterium Chlorobaculum tepidum.  

Science.gov (United States)

The mutant lacking enzymes BciA and BchU, that catalyzed reduction of the C8-vinyl group and methylation at the C20 position of bacteriochlorophyll (BChl) c, respectively, in the green sulfur bacterium Chlorobaculum tepidum, were constructed. This mutant accumulated C8-vinyl-BChl d derivatives, and a molecular structure of the major pigment was fully characterized by its NMR, mass, and circular dichroism spectra, as well as by chemical modification: (3(1) R)-8-vinyl-12-ethyl-(R[V,E])BChl d was confirmed as a new BChl d species in the cells. In vitro chlorosome-like self-aggregates of this pigment were prepared in an aqueous micellar solution, and formed more rapidly than those of (3(1) R)-8,12-diethyl-(R[E,E])BChl d isolated from the green sulfur bacterium Chlorobaculum parvum NCIB8327d synthesizing BChl d homologs. Their red-shifted Q y absorption bands were almost the same at 761 nm, and the value was larger than those of in vitro self-aggregates of R[E,E]BChl c (737 nm) and R[V,E]BChl c (726 nm), while the monomeric states of the former gave Q y bands at shorter wavelengths than those of the latter. Red shifts by self-aggregation of the two BChl d species were estimated to be 110 nm and much larger than those by BChls c (75 nm for [E,E] and 64 nm for [V,E]). PMID:24789521

Harada, Jiro; Mizoguchi, Tadashi; Nomura, Kota; Tamiaki, Hitoshi

2014-07-01

180

Sulfur Dioxide  

Science.gov (United States)

You are here: EPA Home Air & Radiation Six Common Pollutants Sulfur Dioxide Announcements April 17, 2014 - EPA proposes options ... public health benefits through reductions in emissions of sulfur dioxide (SO 2 ) and nitrogen oxides (NOx), the primary causes of acid rain.

 
 
 
 
181

Sulfite oxidation in the purple sulfur bacterium Allochromatium vinosum: identification of SoeABC as a major player and relevance of SoxYZ in the process.  

Science.gov (United States)

In phototrophic sulfur bacteria, sulfite is a well-established intermediate during reduced sulfur compound oxidation. Sulfite is generated in the cytoplasm by the reverse-acting dissimilatory sulfite reductase DsrAB. Many purple sulfur bacteria can even use externally available sulfite as a photosynthetic electron donor. Nevertheless, the exact mode of sulfite oxidation in these organisms is a long-standing enigma. Indirect oxidation in the cytoplasm via adenosine-5'-phosphosulfate (APS) catalysed by APS reductase and ATP sulfurylase is neither generally present nor essential. The inhibition of sulfite oxidation by tungstate in the model organism Allochromatium vinosum indicated the involvement of a molybdoenzyme, but homologues of the periplasmic molybdopterin-containing SorAB or SorT sulfite dehydrogenases are not encoded in genome-sequenced purple or green sulfur bacteria. However, genes for a membrane-bound polysulfide reductase-like iron-sulfur molybdoprotein (SoeABC) are universally present. The catalytic subunit of the protein is predicted to be oriented towards the cytoplasm. We compared the sulfide- and sulfite-oxidizing capabilities of A. vinosum WT with single mutants deficient in SoeABC or APS reductase and the respective double mutant, and were thus able to prove that SoeABC is the major sulfite-oxidizing enzyme in A. vinosum and probably also in other phototrophic sulfur bacteria. The genes also occur in a large number of chemotrophs, indicating a general importance of SoeABC for sulfite oxidation in the cytoplasm. Furthermore, we showed that the periplasmic sulfur substrate-binding protein SoxYZ is needed in parallel to the cytoplasmic enzymes for effective sulfite oxidation in A. vinosum and provided a model for the interplay between these systems despite their localization in different cellular compartments. PMID:24030319

Dahl, Christiane; Franz, Bettina; Hensen, Daniela; Kesselheim, Anne; Zigann, Renate

2013-12-01

182

Highly purified photosynthetic reaction center (PscA/cytochrome c551)2 complex of the green sulfur bacterium Chlorobium limicola.  

Science.gov (United States)

The photosynthetic reaction center (RC) complex that forms a homodimer of core and cytochrome c subunits was isolated from Chlorobium limicola f. thiosulfatophilum, strain Larsen. The complex showed only two subunit bands at 68 (PscA core) and 21 kDa (cytochrome c551) on SDS-PAGE analysis, indicating the complete deletion of the light-harvesting bacteriochlorophyll a (BChl a) protein as well as the iron-sulfur protein. It contained 27 +/- 3 molecules of BChl a, 7 +/- 1 Chl-670, 3 +/- 1 carotenoids, and 1.6 +/- 0.1 c-type hemes per the primary electron donor P840. The complex showed a light-induced charge separation and recombination between P840 and the acceptor Chl-670 at 77 K as follows: P840*Chl-670-->P840+Chl-670(-)-->P840TChl-670-->P84 0 Chl-670. Pigment compositions and their function in the (PscA/cytochrome c551)2 complex were studied by absorption, circular dichroism, and fluorescence spectroscopy. PMID:7548069

Oh-oka, H; Kakutani, S; Kamei, S; Matsubara, H; Iwaki, M; Itoh, S

1995-10-10

183

Highly purified photosynthetic reaction center (PscA/Cytochrome C{sub 551}){sub 2} complex of the green sulfur bacterium chlorobium limicola  

Energy Technology Data Exchange (ETDEWEB)

The photosynthetic reaction center (RC) complex that forms a homodimer of core and cytochrome c subunits was isolated form Chlorobium limicola f. thiosulfatophilum, strain Larsen. The complex showed only two subunit bands at 68 (PscA core) and 21 kDa (cytochrome c{sub 551}) on SDS-PAGE analysis, indicating the complete deletion of the light-harvesting bacteriochlorophyll {alpha} (BChl {alpha}) protein as well s the iron-sulfur protein. It contained 27 {plus_minus} 3 molecules of BChl {alpha}, 7 {plus_minus} 1 Chl-670, 3 {plus_minus} 1 carotenoids, and 1.6 {plus_minus}0.1 c-type hemes per the primary electron donor P840. The complex showed a light-induced charge separation and recombination between P840 and the acceptor Chl-670 at 77 K as follows: P840{sup *}Chl-670{r_arrow}P840{sup +}Chl-670{sup {minus}}{r_arrow}P840{sup T}Chl-670{r_arrow}P840 Chl-670. Pigment compositions and their function in the (PscA/cytochrome c{sub 551}){sub 2} complex were studied by absorption, circular dichroism, and fluorescence spectroscopy 36 refs., 8 figs.

H. Oh-oka; S. Kakutani; S. Kamei [Osaka Univ. (Japan)]|[National Inst. for Basic Biology, Okazaki (Japan)

1995-10-10

184

Thiomicrospira kuenenii sp. nov. and Thiomicrospira frisia sp. nov., two mesophilic obligately chemolithoautotrophic sulfur-oxidizing bacteria isolated from an intertidal mud flat.  

Science.gov (United States)

Two new members of the genus Thiomicrospira were isolated from an intertidal mud flat sample with thiosulfate as the electron donor and CO2 as carbon source. On the basis of differences in genotypic and phenotypic characteristics, it is proposed that strain JB-A1T (= DSM 12350T) and strain JB-A2T (= DSM 12351T) are members of two new species, Thiomicrospira kuenenii and Thiomicrospira frisia, respectively. The cells were Gram-negative vibrios or slightly bent rods. Strain JB-A1T was highly motile, whereas strain JB-A2T showed a much lower degree of motility combined with a strong tendency to form aggregates. Both organisms were obligately autotrophic and strictly aerobic. Nitrate was not used as electron acceptor. Chemolithoautotrophic growth was observed with thiosulfate, tetrathionate, sulfur and sulfide. Neither isolate was able to grow heterotrophically. For strain JB-A1T, growth was observed between pH values of 4.0 and 7.5 with an optimum at pH 6.0, whereas for strain JB-A2T, growth was observed between pH 4.2 and 8.5 with an optimum at pH 6.5. The temperature limits for growth were between 3.5 and 42 degrees C and 3.5 and 39 degrees C, respectively. The optimum growth temperature for strain JB-A1T was between 29 and 33.5 degrees C, whereas strain JB-A2T showed optimal growth between 32 and 35 degrees C. The mean maximum growth rate on thiosulfate was 0.35 h-1 for strain JB-A1T and 0.45 h-1 for strain JB-A2T. PMID:10319459

Brinkhoff, T; Muyzer, G; Wirsen, C O; Kuever, J

1999-04-01

185

Thioalkalimicrobium aerophilum gen. nov., sp. nov. and Thioalkalimicrobium sibericum sp. nov., and Thioalkalivibrio versutus gen. nov., sp. nov., Thioalkalivibrio nitratis sp.nov., novel and Thioalkalivibrio denitrificancs sp. nov., novel obligately alkaliphilic and obligately chemolithoautotrophic sulfur-oxidizing bacteria from soda lakes.  

Science.gov (United States)

Forty-three strains of obligately chemolithoautotrophic sulfur-oxidizing bacteria were isolated from highly alkaline soda lakes in south-east Siberia (Russia) and in Kenya using a specific enrichment procedure at pH 10. The main difference between the novel isolates and known sulfur bacteria was their potential to grow and oxidize sulfur compounds at pH 10 and higher. The isolates fell into two groups that were substantially different from each other physiologically and genetically. Most of the Siberian isolates belonged to the group with a low DNA G+C content (48.0-51.2 mol%). They were characterized by a high growth rate, a low growth yield, a high cytochrome content, and high rates of oxidation of sulfide and thiosulfate. This group included 18 isolates with a DNA homology of more than 40%, and it is described here as a new genus, Thioalkalimicrobium, with two species Thioalkalimicrobium aerophilum (type species) and Thioalkalimicrobium sibericum. The other isolates, mainly from Kenyan soda lakes, fell into a group with a high DNA G+C content (61.0-65.6 mol%). In general, this group was characterized by a low growth rate, a high molar growth yield and low, but relatively equal, rates of oxidation of thiosulfate, sulfide, elemental sulfur and polythionates. The group included 25 isolates with a DNA homology of more than 30%. It was less compact than Thioalkalimicrobium, containing haloalkalophilic, carotenoid-producing, nitrate-reducing and facultatively anaerobic denitrifying strains. These bacteria are proposed to be assigned to a new genus, Thioalkalivibrio, with three species Thioalkalivibrio versutus (type species), Thioalkalivibrio denitrificans and Thioalkalivibrio nitratis. Phylogenetic analysis revealed that both groups belong to the gamma-Proteobacteria. The Thioalkalimicrobium species were closely affiliated with the neutrophilic chemolithoautotrophic sulfur bacteria of the genus Thiomicrospira, forming a new alkaliphilic lineage in this cluster. In contrast, Thioalkalivibrio was not related to any known chemolithoautotrophic taxa, but was distantly associated with anaerobic purple sulfur bacteria of the genus Ectothiorhodospira. PMID:11321103

Sorokin, D Y; Lysenko, A M; Mityushina, L L; Tourova, T P; Jones, B E; Rainey, F A; Robertson, L A; Kuenen, G J

2001-03-01

186

Binning of shallowly sampled metagenomic sequence fragments reveals that low abundance bacteria play important roles in sulfur cycling and degradation of complex organic polymers in an acid mine drainage community  

Science.gov (United States)

Our understanding of environmental microbiology has been greatly enhanced by community genome sequencing of DNA recovered directly the environment. Community genomics provides insights into the diversity, community structure, metabolic function, and evolution of natural populations of uncultivated microbes, thereby revealing dynamics of how microorganisms interact with each other and their environment. Recent studies have demonstrated the potential for reconstructing near-complete genomes from natural environments while highlighting the challenges of analyzing community genomic sequence, especially from diverse environments. A major challenge of shotgun community genome sequencing is identification of DNA fragments from minor community members for which only low coverage of genomic sequence is present. We analyzed community genome sequence retrieved from biofilms in an acid mine drainage (AMD) system in the Richmond Mine at Iron Mountain, CA, with an emphasis on identification and assembly of DNA fragments from low-abundance community members. The Richmond mine hosts an extensive, relatively low diversity subterranean chemolithoautotrophic community that is sustained entirely by oxidative dissolution of pyrite. The activity of these microorganisms greatly accelerates the generation of AMD. Previous and ongoing work in our laboratory has focused on reconstrucing genomes of dominant community members, including several bacteria and archaea. We binned contigs from several samples (including one new sample and two that had been previously analyzed) by tetranucleotide frequency with clustering by Self-Organizing Maps (SOM). The binning, evaluated by comparison with information from the manually curated assembly of the dominant organisms, was found to be very effective: fragments were correctly assigned with 95% accuracy. Improperly assigned fragments often contained sequences that are either evolutionarily constrained (e.g. 16S rRNA genes) or mobile elements that are not expected to reflect the tetranucleotide frequency signature of the host genome. Four unknown tetranucleotide frequency clusters with significant sequence (6 Mb total) were noted and analyzed further. Based on phylogenetic markers and BLAST results, these clusters represent low abundance bacteria including Acintobacteria, Firmicutes, and Proteobacteria. Functional analysis of these clusters revealved that the low- abundance bacteria harbor genes that could potentially encode important ecosystem functions such as sulfur utilization (e.g. polysulfide reductase) and polymer degradation (e.g. chitinase and glycoside hydrolase). We conclude that ESOM clustering of tetranucleotide frequency patterns is an effective method for rapidly binning shotgun community genomic sequences and a valuable tool for analyzing minor community members, which despite their low abundance may play crucial ecological roles.

Dick, G. J.; Andersson, A.; Banfield, J. F.

2007-12-01

187

Widespread distribution in pathogenic bacteria of di-iron proteins that repair oxidative and nitrosative damage to iron-sulfur centers.  

Science.gov (United States)

Expression of two genes of unknown function, Staphylococcus aureus scdA and Neisseria gonorrhoeae dnrN, is induced by exposure to oxidative or nitrosative stress. We show that DnrN and ScdA are di-iron proteins that protect their hosts from damage caused by exposure to nitric oxide and to hydrogen peroxide. Loss of FNR-dependent activation of aniA expression and NsrR-dependent repression of norB and dnrN expression on exposure to NO was restored in the gonococcal parent strain but not in a dnrN mutant, suggesting that DnrN is necessary for the repair of NO damage to the gonococcal transcription factors, FNR and NsrR. Restoration of aconitase activity destroyed by exposure of S. aureus to NO or H2O2 required a functional scdA gene. Electron paramagnetic resonance spectra of recombinant ScdA purified from Escherichia coli confirmed the presence of a di-iron center. The recombinant scdA plasmid, but not recombinant plasmids encoding the complete Escherichia coli sufABCDSE or iscRSUAhscBAfdx operons, complemented repair defects of an E. coli ytfE mutant. Analysis of the protein sequence database revealed the importance of the two proteins based on the widespread distribution of highly conserved homologues in both gram-positive and gram-negative bacteria that are human pathogens. We provide in vivo and in vitro evidence that Fe-S clusters damaged by exposure to NO and H2O2 can be repaired by this new protein family, for which we propose the name repair of iron centers, or RIC, proteins. PMID:18203837

Overton, Tim W; Justino, Marta C; Li, Ying; Baptista, Joana M; Melo, Ana M P; Cole, Jeffrey A; Saraiva, Lígia M

2008-03-01

188

Elemental sulfur in Eddy County, New Mexico  

Science.gov (United States)

Sulfur has been reported in Eddy County, N. Mex., in rocks ranging from Silurian to Holocene in age at depths of 0-15,020 feet. Targets of present exploration are Permian formations in the Delaware Basin and northwest shelf areas at depths of less than 4,000 feet. Most of the reported sulfur occurrences in the shelf area are in the 'Abo' (as used by some subsurface geologists), Yeso, and San Andres Formations and the Artesia Group. Sulfur deposition in the dense dolomites of the 'Abo,' Yeso, and San Andres Formations is attributed to the reduction of ionic sulfate by hydrogen sulfide in formation waters in zones of preexisting porosity and permeability. A similar origin accounts for most of the sulfur deposits in the formations of the Artesia Group, but some of the sulfur in these formations may have originated in place through the alteration of anhydrite to carbonate and sulfur by the metabolic processes of bacteria in the presence of hydrocarbons. Exploration in the Delaware Basin area is directed primarily toward the Castile Formation. Sulfur deposits in the Castile Formation are found in irregular masses of cavernous brecciated secondary carbonate rock enveloped by impermeable anhydrite. The carbonate masses, or 'castiles,' probably originated as collapse features resulting from subsurface solution and upward stopping. Formation of carbonate rock and sulfur in the castiles is attributed to the reduction of brecciated anhydrite by bacteria and hydrocarbons in the same process ascribed to the formation of carbonate and sulfur in the caprocks of salt domes.

Hinds, Jim S.; Cunningham, Richard R.

1970-01-01

189

Marine bacteria from Danish coastal waters show antifouling activity against the marine fouling bacterium Pseudoalteromonas sp. strain S91 and zoospores of the green alga Ulva australis independent of bacteriocidal activity.  

Science.gov (United States)

The aims of this study were to determine if marine bacteria from Danish coastal waters produce antifouling compounds and if antifouling bacteria could be ascribed to specific niches or seasons. We further assess if antibacterial effect is a good proxy for antifouling activity. We isolated 110 bacteria with anti-Vibrio activity from different sample types and locations during a 1-year sampling from Danish coastal waters. The strains were identified as Pseudoalteromonas, Phaeobacter, and Vibrionaceae based on phenotypic tests and partial 16S rRNA gene sequence similarity. The numbers of bioactive bacteria were significantly higher in warmer than in colder months. While some species were isolated at all sampling locations, others were niche specific. We repeatedly isolated Phaeobacter gallaeciensis at surfaces from one site and Pseudoalteromonas tunicata at two others. Twenty-two strains, representing the major taxonomic groups, different seasons, and isolation strategies, were tested for antiadhesive effect against the marine biofilm-forming bacterium Pseudoalteromonas sp. strain S91 and zoospores of the green alga Ulva australis. The antiadhesive effects were assessed by quantifying the number of strain S91 or Ulva spores attaching to a preformed biofilm of each of the 22 strains. The strongest antifouling activity was found in Pseudoalteromonas strains. Biofilms of Pseudoalteromonas piscicida, Pseudoalteromonas tunicata, and Pseudoalteromonas ulvae prevented Pseudoalteromonas S91 from attaching to steel surfaces. P. piscicida killed S91 bacteria in the suspension cultures, whereas P. tunicata and P. ulvae did not; however, they did prevent adhesion by nonbactericidal mechanism(s). Seven Pseudoalteromonas species, including P. piscicida and P. tunicata, reduced the number of settling Ulva zoospores to less than 10% of the number settling on control surfaces. The antifouling alpP gene was detected only in P. tunicata strains (with purple and yellow pigmentation), so other compounds/mechanisms must be present in the other Pseudoalteromonas strains with antifouling activity. PMID:22003011

Bernbom, Nete; Ng, Yoke Yin; Kjelleberg, Staffan; Harder, Tilmann; Gram, Lone

2011-12-01

190

Marine Bacteria from Danish Coastal Waters Show Antifouling Activity against the Marine Fouling Bacterium Pseudoalteromonas sp. Strain S91 and Zoospores of the Green Alga Ulva australis Independent of Bacteriocidal Activity?†  

Science.gov (United States)

The aims of this study were to determine if marine bacteria from Danish coastal waters produce antifouling compounds and if antifouling bacteria could be ascribed to specific niches or seasons. We further assess if antibacterial effect is a good proxy for antifouling activity. We isolated 110 bacteria with anti-Vibrio activity from different sample types and locations during a 1-year sampling from Danish coastal waters. The strains were identified as Pseudoalteromonas, Phaeobacter, and Vibrionaceae based on phenotypic tests and partial 16S rRNA gene sequence similarity. The numbers of bioactive bacteria were significantly higher in warmer than in colder months. While some species were isolated at all sampling locations, others were niche specific. We repeatedly isolated Phaeobacter gallaeciensis at surfaces from one site and Pseudoalteromonas tunicata at two others. Twenty-two strains, representing the major taxonomic groups, different seasons, and isolation strategies, were tested for antiadhesive effect against the marine biofilm-forming bacterium Pseudoalteromonas sp. strain S91 and zoospores of the green alga Ulva australis. The antiadhesive effects were assessed by quantifying the number of strain S91 or Ulva spores attaching to a preformed biofilm of each of the 22 strains. The strongest antifouling activity was found in Pseudoalteromonas strains. Biofilms of Pseudoalteromonas piscicida, Pseudoalteromonas tunicata, and Pseudoalteromonas ulvae prevented Pseudoalteromonas S91 from attaching to steel surfaces. P. piscicida killed S91 bacteria in the suspension cultures, whereas P. tunicata and P. ulvae did not; however, they did prevent adhesion by nonbactericidal mechanism(s). Seven Pseudoalteromonas species, including P. piscicida and P. tunicata, reduced the number of settling Ulva zoospores to less than 10% of the number settling on control surfaces. The antifouling alpP gene was detected only in P. tunicata strains (with purple and yellow pigmentation), so other compounds/mechanisms must be present in the other Pseudoalteromonas strains with antifouling activity.

Bernbom, Nete; Ng, Yoke Yin; Kjelleberg, Staffan; Harder, Tilmann; Gram, Lone

2011-01-01

191

Marine Bacteria from Danish Coastal Waters Show Antifouling Activity against the Marine Fouling Bacterium Pseudoalteromonas sp. Strain S91 and Zoospores of the Green Alga Ulva australis Independent of Bacteriocidal Activity  

DEFF Research Database (Denmark)

The aims of this study were to determine if marine bacteria from Danish coastal waters produce antifouling compounds and if antifouling bacteria could be ascribed to specific niches or seasons. We further assess if antibacterial effect is a good proxy for antifouling activity. We isolated 110 bacteria with anti-Vibrio activity from different sample types and locations during a 1-year sampling from Danish coastal waters. The strains were identified as Pseudoalteromonas, Phaeobacter, and Vibrionaceae based on phenotypic tests and partial 16S rRNA gene sequence similarity. The numbers of bioactive bacteria were significantly higher in warmer than in colder months. While some species were isolated at all sampling locations, others were niche specific. We repeatedly isolated Phaeobacter gallaeciensis at surfaces from one site and Pseudoalteromonas tunicata at two others. Twenty-two strains, representing the major taxonomic groups, different seasons, and isolation strategies, were tested for antiadhesive effect against the marine biofilm-forming bacterium Pseudoalteromonas sp. strain S91 and zoospores of the green alga Ulva australis. The antiadhesive effects were assessed by quantifying the number of strain S91 or Ulva spores attaching to a preformed biofilm of each of the 22 strains. The strongest antifouling activity was found in Pseudoalteromonas strains. Biofilms of Pseudoalteromonas piscicida, Pseudoalteromonas tunicata, and Pseudoalteromonas ulvae prevented Pseudoalteromonas S91 from attaching to steel surfaces. P. piscicida killed S91 bacteria in the suspension cultures, whereas P. tunicata and P. ulvae did not; however, they did prevent adhesion by nonbactericidal mechanism(s). Seven Pseudoalteromonas species, including P. piscicida and P. tunicata, reduced the number of settling Ulva zoospores to less than 10% of the number settling on control surfaces. The antifouling alpP gene was detected only in P. tunicata strains (with purple and yellow pigmentation), so other compounds/mechanisms must be present in theother Pseudoalteromonas strains with antifouling activity.

Bernbom, Nete; Ng, Yoke Yin

2011-01-01

192

Identification of a fourth family of lycopene cyclases in photosynthetic bacteria.  

Science.gov (United States)

A fourth and large family of lycopene cyclases was identified in photosynthetic prokaryotes. The first member of this family, encoded by the cruA gene of the green sulfur bacterium Chlorobium tepidum, was identified in a complementation assay with a lycopene-producing strain of Escherichia coli. Orthologs of cruA are found in all available green sulfur bacterial genomes and in all cyanobacterial genomes that lack genes encoding CrtL- or CrtY-type lycopene cyclases. The cyanobacterium Synechococcus sp. PCC 7002 has two homologs of CruA, denoted CruA and CruP, and both were shown to have lycopene cyclase activity. Although all characterized lycopene cyclases in plants are CrtL-type proteins, genes orthologous to cruP also occur in plant genomes. The CruA- and CruP-type carotenoid cyclases are members of the FixC dehydrogenase superfamily and are distantly related to CrtL- and CrtY-type lycopene cyclases. Identification of these cyclases fills a major gap in the carotenoid biosynthetic pathways of green sulfur bacteria and cyanobacteria. PMID:17606904

Maresca, Julia A; Graham, Joel E; Wu, Martin; Eisen, Jonathan A; Bryant, Donald A

2007-07-10

193

Isolation and structure determination of a complete set of bacteriochlorophyll-d homologs and epimers from a green sulfur bacterium Chlorobium vibrioforme and their aggregation properties in hydrophobic solvents.  

Science.gov (United States)

Eight bacteriochlorophyll (BChl)-d homologs and epimers were isolated from a strain of the green sulfur bacterium Chlorobium vibrioforme. By a combination of mass spectrometry and 1H-NMR spectroscopy using the chemical shifts of meso- and 3(1)-protons and 1H-1H NOE correlations, the molecular structures were determined as (3(1)R)-8-ethyl-12-methyl, (3'R)-8-ethyl-12-ethyl, (3(1)R)-8-propyl-12-methyl, (3(1)S)-8-propyl-12-methyl, (3(1)R)-8-propyl-12-ethyl, (3(1)S)-8-propyl-12-ethyl, (3(1)S)-8-isobutyl-12-methyl and (3(1)S)-8-isobutyl-12-ethyl. The aggregation behavior of the epimerically pure BChls-d in hydrophobic organic solvents was examined to investigate the absolute configuration of the 3-(1-hydroxyethyl) group as well as the bulkiness of the C8 and C12 side-chains by using electronic-absorption and fluorescence-emission spectroscopies At high concentration of the BChls-d in CH2Cl2, the absolute configuration of the 3-(1-hydroxyethyl) group governed the formation of a subunit as a building block for the subsequent higher assembly. Upon dilution of the resulting subunit with hexane, the bulkiness of the C8 and C12 side-chains were found to affect the association of the subunits differently: the bulkiness of the C8 side-chain acted as a promoter for the association due to a stabilized hydrophobic interaction among the relevant larger side-chain, whereas the bulkiness of the C12 side-chain acted as an inhibitor for that association due to introduction of a particular steric-hindrance around the side-chain in the aggregates. PMID:12656478

Mizoguchi, Tadashi; Saga, Yoshitaka; Tamiaki, Hitoshi

2002-10-01

194

Insertional inactivation studies of the csmA and csmC genes of the green sulfur bacterium Chlorobium vibrioforme 8327: the chlorosome protein CsmA is required for viability but CsmC is dispensable.  

Science.gov (United States)

Targeted mutagenesis was used to investigate the roles of the CsmA and CsmC proteins of the chlorosomes of the green bacteria Chlorobium tepidum and Chlorobium vibrioforme 8327. Under the photoautotrophic growth conditions employed, CsmA is required for the viability of the cells but CsmC is dispensable. The absence of CsmC caused a small red shift in the near-infrared absorption maximum of bacteriochlorophyll d in whole cells and chlorosomes, but chlorosomes were assembled in and could be isolated from the csmC mutant. The doubling time of the csmC mutant was approximately twice that of the wild-type strain. Fluorescence emission measurements suggested that energy transfer from the bulk bacteriochlorophyll d to another pigment, perhaps bacteriochlorophyll a, emitting at 800-804 nm, was less efficient in the csmC mutant cells than in wild-type cells. These studies establish that transformation and homologous recombination can be employed in targeted mutagenesis of Chlorobium sp. and further demonstrate that chlorosome proteins play important roles in the structure and function of these light-harvesting organelles. PMID:9682485

Chung, S; Shen, G; Ormerod, J; Bryant, D A

1998-07-15

195

Biochemistry of Dissimilatory Sulfur Oxidation  

Energy Technology Data Exchange (ETDEWEB)

The long term goals of this research were to define the substrate oxidation pathways, the electron transport mechanisms, and the modes of energy conservation employed during the dissimilatory oxidation of sulfur practiced by various species of the thiobacilli. Specific adhesion of the thiobacilli to elemental sulfur was studied by electrical impedance, dynamic light scattering, laser Doppler velocimetry, and optical trapping methods. The conclusion is that the thiobacilli appear to express specific receptors that enable the bacteria to recognize and adhere to insoluble sulfur. The enzyme tetrathionate oxidase was purified from two species of the thiobacilli. Extensive structural and functional studies were conducted on adenosine 5'-phosphosulfate reductase purified from cell-free extracts of Thiobacillus denitrificans. The kinetic mechanism of rhodanese was studied.

Blake II, R.

2003-05-30

196

Bacteria and Acidic Drainage from Coal Refuse: Inhibition by Sodium Lauryl Sulfate and Sodium Benzoate  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The application of an aqueous solution of sodium lauryl sulfate and sodium benzoate to the surface of high-sulfur coal refuse resulted in the inhibition of iron-and sulfur-oxidizing chemoautotrophic bacteria and in the decrease of acidic drainage from the refuse, suggesting that acid drainage can be abated in the field by inhibiting iron- and sulfur-oxidizing bacteria.

Dugan, Patrick R.; Apel, William A.

1983-01-01

197

Enhancement of Copper Availability and Microbial Community Changes in Rice Rhizospheres Affected by Sulfur  

Directory of Open Access Journals (Sweden)

Full Text Available The role of sulfur on the availability of Cu and the bacterial community in rice rhizospheres was investigated by pot experiments. With sulfur addition, pH in rhizosphere soil decreased and Mg(NO32 extractable Cu increased significantly. The bacterial community composition also changed with sulfur addition. Some specific clones having high similarity to Thiobacillus, which indicated that sulfur oxidation in the rice rhizosphere could increase the availability of Cu. These results suggested that sulfur source which could provide substrate to sulfur oxidizing bacteria and enhance the availability of Cu was not a suitable sulfur fertilizer for Cu polluted soil.

Xiao-Feng Yuan

2011-02-01

198

Determination of different sulfur forms with application to environmental research  

International Nuclear Information System (INIS)

Knowledge on the behavior of sulfur in the environment requires investigation on a molecular level. With that, chemical states of sulfur can be determined and can be used to track, e.g., microbially catalyzed remediation measurements of acidic mine waters and mineral bacteria interactions. ANKA provides an X-ray absorption beamline that is optimum for measurements at the sulfur K edge. Basics, experimental set-up, applications, and future upgrades are presented. (orig.)

2005-01-01

199

Greening economy, greening people  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Green economy is one that generates increasing prosperity while maintaining the natural systems that sustain us. The greening of economies is not generally a drag on growth but rather a new engine of growth; that it is a net generator of decent jobs, and that it is also a vital strategy for the elimination of persistent poverty. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/31039

Bandzeladze, T.

2013-01-01

200

Microbiological disproportionation of inorganic sulfur compounds  

DEFF Research Database (Denmark)

The disproportionation of inorganic sulfur intermediates at moderate temperatures (0-80 °C) is a microbiologically catalyzed chemolithotrophic process in which compounds like elemental sulfur, thiosulfate, and sulfite serve as both electron donor and acceptor, and generate hydrogen sulfide and sulfate. Thus the overall process is comparable to the fermentation of organic compounds such as glucose and is consequently often described as 'inorganic fermentation'. The process is primarily carried out by microorganisms with phylogenetic affiliation to the so called sulfate-reducing bacteria within the delta subclass of Proteobacteria. The organisms grow with sulfate as their external electron acceptor and low-molecular weight organic compounds or hydrogen as energy sources. Studies of the biochemistry of a few isolates indicate that the disproportionating microbes reverse the sulfate reduction pathway during disproportionation. However, investigations with elemental sulfur disproportionating bacteria present evidence for an alternative pathway involving the enzyme sulfite-oxidoreductase, an enzyme that has hitherto only been reported participating in the oxidation of sulfite in aerobic or phototrophic sulfide oxidizers. Investigations bridging geology and microbiology have found strong evidence for disproportionating bacteria participating in and enhancing the rate at which pyrite forms and being partly responsible for the isotopic signatures of sulfidic minerals in recent and old sediments. New results indicate that elemental sulfur disproportionating microbes can be traced back in time as long as 3.5 billion years and elemental sulfur disproportionation would thus be one the oldest biological processes on Earth.

Finster, Kai

2008-01-01

 
 
 
 
201

Methylotrophic bacteria symbiosis with the higher plants as means of minimization of the lower hydrocarbons concentration during artificial ecosystem gas exchange  

Science.gov (United States)

Plant growth unit should be included in the LSS for the space vehicles for vitamin greens supply and psychological support of cosmonauts during long-term missions. The lower hydrocarbons such as methane, methanol, methylated sulfuric compounds and methylated amines, ethylene and so on, are the natural products of human and plant metabolism and usually considered as the air pollutions. It is shown, that one way to decrease the lower hydrocarbons concentration in the artificial ecosystems could be colonization of the plants by methylotrophic bacteria. The aerobic methylotrophic bacteria possess unique ability to use methane and its oxidized or replaced derivatives without food damage and human, animals or plants infection. We have found that methylotrophic bacteria are the phyto-symbiotic bacteria: they stimulate growth and development of the colonized plants because of synthesizing cytokinins and auxins, and vitamin B12.Two collection strains of the obligate methylotrophic bacteria - Methylovorus mays C and Methylomonas metanica S - were chosen because of their high activity to assimilate the lower hydrocarbons due to functioning of methanoldehydrogenase, methanmonooxigenase and ribulose monophosphate cycle enzymes system.Colonization of the leaf cabbage Brassica chinensis L. by these strains led to approximately 30 % reduce of methanol and methane concentration in the air inside phytotron. Experimental estimations of the influence of methylotrophic bacteria on leafy greens growth and development are obtained.

Berkovich, Yuliy; Smolyanina, Svetlana; Moukhamedieva, Lana; Mardanov, Robert; Doronina, Nina; Ivanova, Ekaterina

202

Autotrophy of green non-sulphur bacteria in hot spring microbial mats: biological explanations for isotopically heavy organic carbon in the geological record  

Science.gov (United States)

Inferences about the evidence of life recorded in organic compounds within the Earth's ancient rocks have depended on 13C contents low enough to be characteristic of biological debris produced by the well-known CO2 fixation pathway, the Calvin cycle. 'Atypically' high values have been attributed to isotopic alteration of sedimentary organic carbon by thermal metamorphism. We examined the possibility that organic carbon characterized by a relatively high 13C content could have arisen biologically from recently discovered autotrophic pathways. We focused on the green non-sulphur bacterium Chloroflexus aurantiacus that uses the 3-hydroxypropionate pathway for inorganic carbon fixation and is geologically significant as it forms modern mat communities analogous to stromatolites. Organic matter in mats constructed by Chloroflexus spp. alone had relatively high 13C contents (-14.9%) and lipids diagnostic of Chloroflexus that were also isotopically heavy (-8.9% to -18.5%). Organic matter in mats constructed by Chloroflexus in conjunction with cyanobacteria had a more typical Calvin cycle signature (-23.5%). However, lipids diagnostic of Chloroflexus were isotopically enriched (-15.1% to -24.1%) relative to lipids typical of cyanobacteria (-33.9% to -36.3%). This suggests that, in mats formed by both cyanobacteria and Chloroflexus, autotrophy must have a greater effect on Chloroflexus carbon metabolism than the photoheterotrophic consumption of cyanobacterial photosynthate. Chloroflexus cell components were also selectively preserved. Hence, Chloroflexus autotrophy and selective preservation of its products constitute one purely biological mechanism by which isotopically heavy organic carbon could have been introduced into important Precambrian geological features.

van der Meer, M. T.; Schouten, S.; de Leeuw, J. W.; Ward, D. M.

2000-01-01

203

Two sulfur-containing ansamycin antibiotics from Streptomyces albolongus.  

Science.gov (United States)

Two sulfur-containing ansamycin antibiotics were isolated from the culture broth of Streptomyces albolongus C-46366; the major one was identical with awamycin and the minor one was a new ansamycin antibiotic, ansathiazin. Their structures were elucidated from their reactions and spectroscopic analyses. These antibiotics were active against gram-positive bacteria, acid-fast bacteria and a protozoan. PMID:3770139

Tanida, S; Shinagwa, S; Takizawa, M; Takahashi, T; Harada, S; Hasegawa, T

1986-10-15

204

Sulfur dioxide in geothermal waters and gases  

Energy Technology Data Exchange (ETDEWEB)

Methods were developed for stabilizing SO/sub 2/ in water and gas samples. The pararosaniline colorimetric method, and a gas chromatographic method using a flame photometric detector specific for sulfur gases were used to assay SO/sub 2/. Assays were also performed for sulfide, elemental sulfur and sulfate. A large number of acidic, neutral, and alkaline springs in Yellowstone National Park were sampled: SO/sub 2/ was found in small amounts in most of them. The highest concentration detected in water was 0.5-0.6 ..mu..g/ml (expressed as sulfur). Sulfur dioxide was never detected in gases emanating from hot springs, or in fumaroles, although H/sub 2/S was readily detected. Because of the high solubility of SO/sub 2/ in water, and its low pK, it is unlikely that environmentally significant quantities are volatilized from geothermal systems of the low-temperature type characteristic of Yellowstone Park. Laboratory studies suggest that in acid waters, ferric iron is the primary oxidant, as H/sub 2/S is not oxidized by O/sub 2/ at low pH. At neutral or alkaline pH, O/sub 2/ is the likely oxidant, because sulfide is oxidized by O/sub 2/ at these pH values, and neutral and alkali hot springs are always low in iron. Although bacteria capable of oxidizing sulfide and elemental sulfur are present in most of the springs sampled, it is concluded that the oxidation of reduced sulfur compounds to sulfur dioxide is primarily a chemical process, because of the rapidity with which it occurs and the lack of any evidence that bacteria produce sulfur dioxide.

Zinder, S.; Brock, T.D.

1977-01-01

205

Microbial pathways in colonic sulfur metabolism and links with health and disease  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Sulfur is both crucial to life and a potential threat to health. While colonic sulfur metabolism mediated by eukaryotic cells is relatively well studied, much less is known about sulfur metabolism within gastrointestinal microbes. Sulfated compounds in the colon are either of inorganic (e.g., sulfates, sulfites) or organic (e.g., dietary amino acids and host mucins) origin. The most extensively studied of the microbes involved in colonic sulfur metabolism are the sulfate-reducing bacteria (SR...

Carbonero, Franck; Benefiel, Ann C.; Alizadeh-ghamsari, Amir H.; Gaskins, H. Rex

2012-01-01

206

Green Alliance  

...Green Alliance You are here: Staff Karen Crane staff Karen Crane head of communications direct dial: 020 7630 4519 email: kcrane@green-alliance....uk Karen leads on brand and communications development at Green Alliance. She oversees the events and publications programmes, media activity, online ... Karen edits Green Alliance’s publications, including Inside Track, Green Alliance’s magazine, a platform for informed commentary on environmental politics and policy ...

207

Microbial Sulfur Cycle in Two Hydrothermal Chimneys on the Southwest Indian Ridge  

Science.gov (United States)

ABSTRACT Sulfur is an important element in sustaining microbial communities present in hydrothermal vents. Sulfur oxidation has been extensively studied due to its importance in chemosynthetic pathways in hydrothermal fields; however, less is known about sulfate reduction. Here, the metagenomes of hydrothermal chimneys located on the ultraslow-spreading Southwest Indian Ridge (SWIR) were pyrosequenced to elucidate the associated microbial sulfur cycle. A taxonomic summary of known genes revealed a few dominant bacteria that participated in the microbial sulfur cycle, particularly sulfate-reducing Deltaproteobacteria. The metagenomes studied contained highly abundant genes related to sulfur oxidation and reduction. Several carbon metabolic pathways, in particular the Calvin-Benson-Bassham pathway and the reductive tricarboxylic acid cycles for CO2 fixation, were identified in sulfur-oxidizing autotrophic bacteria. In contrast, highly abundant genes related to the oxidation of short-chain alkanes were grouped with sulfate-reducing bacteria, suggesting an important role for short-chain alkanes in the sulfur cycle. Furthermore, sulfur-oxidizing bacteria were associated with enrichment for genes involved in the denitrification pathway, while sulfate-reducing bacteria displayed enrichment for genes responsible for hydrogen utilization. In conclusion, this study provides insights regarding major microbial metabolic activities that are driven by the sulfur cycle in low-temperature hydrothermal chimneys present on an ultraslow midocean ridge.

Cao, Huiluo; Wang, Yong; Lee, On On; Zeng, Xiang; Shao, Zongze; Qian, Pei-Yuan

2014-01-01

208

Sulfuric acid poisoning  

Science.gov (United States)

Sulfuric acid is a very strong chemical that is corrosive. Corrosive means it can cause severe burns and ... or mucous membranes. This article discusses poisoning from sulfuric acid. This is for information only and not for ...

209

Think big--giant genes in bacteria.  

Science.gov (United States)

Long genes should be rare in archaea and eubacteria because of the demanding costs of time and resources for protein production. The search in 580 sequenced prokaryotic genomes, however, revealed 0.2% of all genes to be longer than 5 kb (absolute number: 3732 genes). Eighty giant bacterial genes of more than 20 kb in length were identified in 47 taxa that belong to the phyla Thermotogae (1), Chlorobi (3), Planctomycetes (1), Cyanobacteria (2), Firmicutes (7), Actinobacteria (9), Proteobacteria (23) or Euryarchaeota (1) (number of taxa in brackets). Giant genes are strain-specific, differ in their tetranucleotide usage from the bulk genome and occur preferentially in non-pathogenic environmental bacteria. The two longest bacterial genes known to date were detected in the green sulfur bacterium Chlorobium chlorochromatii CaD3 encoding proteins of 36 806 and 20 647 amino acids, being surpassed in length only by the human titin coding sequence. More than 90% of bacterial giant genes either encode a surface protein or a polyketide/non-ribosomal peptide synthetase. Most surface proteins are acidic, threonine-rich, lack cystein and harbour multiple amino acid repeats. Giant proteins increase bacterial fitness by the production of either weapons towards or shields against animate competitors or hostile environments. PMID:18237309

Reva, Oleg; Tümmler, Burkhard

2008-03-01

210

Sulfur-metabolizing bacterial populations in microbial mats of the Nakabusa hot spring, Japan.  

Science.gov (United States)

At the Nakabusa hot spring, Japan, dense olive-green microbial mats develop in regions where the slightly alkaline, sulfidic effluent has cooled to 65°C. The microbial community of such mats was analyzed by focusing on the diversity, as well as the in situ distribution and function of bacteria involved in sulfur cycling. Analyses of 16S rRNA and functional genes (aprA, pufM) suggested the importance of three thermophilic bacterial groups: aerobic chemolithotrophic sulfide-oxidizing species of the genus Sulfurihydrogenibium (Aquificae), anaerobic sulfate-reducing species of the genera Thermodesulfobacterium/Thermodesulfatator, and filamentous anoxygenic photosynthetic species of the genus Chloroflexus. A new oligonucleotide probe specific for Sulfurihydrogenibium was designed and optimized for catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH). In situ hybridizations of thin mat sections showed a heterogeneous vertical distribution of Sulfurihydrogenibium and Chloroflexus. Sulfurihydrogenibium dominated near the mat surface (50% of the total mat biovolume), while Chloroflexus dominated in deeper layers (up to 64% of the total mat biovolume). Physiological experiments monitoring in vitro changes of sulfide concentration indicated slight sulfide production by sulfate-reducing bacteria under anoxic-dark conditions, sulfide consumption by photosynthetic bacteria under anoxic-light conditions and strong sulfide oxidation by chemolithotrophic members of Aquificae under oxic-dark condition. We therefore propose that Sulfurihydrogenibium spp. act as highly efficient scavengers of oxygen from the spring water, thus creating a favorable, anoxic environment for Chloroflexus and Thermodesulfobacterium/Thermodesulfatator in deeper layers. PMID:21353426

Kubo, Kyoko; Knittel, Katrin; Amann, Rudolf; Fukui, Manabu; Matsuura, Katsumi

2011-06-01

211

Green Chemistry  

Science.gov (United States)

This special feature page from the American Chemical Society (ACS) showcases the up-and-coming field of "green chemistry," that is, the development of chemical products and processes that eliminate or reduce the use and generation of hazardous substances. A list of principles behind green chemistry, a searchable bibliography of green chemistry references, green chemistry links (including conferences), and an online preview of the ACS-published book Real-World Cases in Green Chemistry are all found at the site. Five video clips on green chemistry from the standpoint of academia, industry, and small business are also featured (Windows Media Player). This page comes from ACS's Green Chemistry Project, a three-year educational project to develop and disseminate green chemistry educational materials for graduate and undergraduate chemistry students. Check back often for updates.

2002-01-01

212

Green Alliance  

...Green Alliance You are here: Staff Louise Humphrey staff Louise Humphrey assistant director direct dial: 020 7630 4518 email: lhumphrey@green-alliance.org.uk Louise is head of the development team at Green Alliance, managing and developing our central support functions. She is also responsible for ...

213

Sulfuric acid on Europa and the radiolytic sulfur cycle  

Science.gov (United States)

A comparison of laboratory spectra with Galileo data indicates that hydrated sulfuric acid is present and is a major component of Europa's surface. In addition, this moon's visually dark surface material, which spatially correlates with the sulfuric acid concentration, is identified as radiolytically altered sulfur polymers. Radiolysis of the surface by magnetospheric plasma bombardment continuously cycles sulfur between three forms: sulfuric acid, sulfur dioxide, and sulfur polymers, with sulfuric acid being about 50 times as abundant as the other forms. Enhanced sulfuric acid concentrations are found in Europa's geologically young terrains, suggesting that low-temperature, liquid sulfuric acid may influence geological processes.

Carlson, R. W.; Johnson, R. E.; Anderson, M. S.

1999-01-01

214

Reduced sulfur in euxinic sediments of the Cariaco Basin : Sulfur isotope contraints on organic sulfur formation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Reduced sulfur accumulation in Holocene and latest Pleistocene euxinic marine sediments from the Cariaco Basin, Venezuela, was investigated to constrain the timing and possible pathways of organic matter (OM) sulfurization. Data were collected for a diverse suite of sulfur species, including concentrations and sulfur isotope compositions of pore-water sulfide, pore-water sulfate, pyrite sulfur, total organic sulfur (TOS), kerogen sulfur (KS), and polar bitumen sulfur (PBS). Results suggest th...

Sinninghe Damste?, J. S.; Werne, J.; Lyons, T. W.; Hollander, D. J.; Formolo, M.

2003-01-01

215

Chlorosomes: antenna organelles in photosynthetic green bacteria  

DEFF Research Database (Denmark)

The new series "Microbiology Monographs" begins with two volumes on intracellular components in prokaryotes. In this second volume, "Complex Intracellular Structures in Prokaryotes", the components, labelled complex intracellular structures, encompass a multitude of important cellular functions. Continuing and newly initiated research will provide a clearer understanding of the complex intracellular structures known at present and will bring to light surprising new ones as well. "Complex Intracellular Structures in Prokaryotes" provides historical background and comprehensive reviews of ten topics that cover the spectrum of the complex intracellular structures of prokaryotes: proteasomes, phycobilisomes, chlorosomes, gas vesicles, carboxysomes, magnetosomes, intracytoplasmic membranes, membrane-bound nucleoids, anammoxosomes, and cytoarchitecture of Epulopiscium spp. Cameos of selected additional structures are presented to broaden the scope of the volume and to generate increased interest in these structures.

Frigaard, N.-U.; Bryant, D. A.

2006-01-01

216

Metaphysical green  

DEFF Research Database (Denmark)

â??Sensation of Green is about the mental process like touching, seeing, hearing, or smelling, resulting from the immediate stimulation of landscape forms, plants, trees, wind and water. Sensation of Green triggers a feeling of scale, cheerfulness, calmness and peace. The spatial performance of Sensation of Green is created by a physical interaction between the language of space and the language of natureâ? The notion of Sensation of Green was developed through a previous study â??Learning from the Summer Houseâ?? investigating the unique architectural characteristics of the Danish summer houses. The idea of the concept is a mutual participation of nature in architecture meaning that landscape features become tools to design a built space. The paper develops the concept further focusing on the scale of a single residential unit. The paper argues that the concept of Sensation of Green is flexible to adapt to urban environment. It explores the potential of Sensation of Green in the city. The paper questions whether the Sensation of Green could introduce a new spectrum of greens, beside the real green. It develops the term of metaphysical green â?? does green have to be green or can it be only the Sensation of Green? Three existing examples are agents to this discussion. The first example is a Danish summer house. The other two are international urban examples. While the summer house articulates the original meaning of Sensation of Green, the urban examples illustrate its urban context. The first example is a tiny Danish summer house from 1918 . The second example is â??House before Houseâ?? , in Tokyo. The third example is a prefabricated house â??CHUâ?? . The analysis evaluates the characteristics of diverse tones of green â?? from green image to green sensation. The analysis is based on the original definition of the concept defined during the summer house study. Learning from these single residential units, the paper ends by questioning the potential of the concept of Sensation of Green concerning a larger urban typology.

Earon, Ofri

217

Biogenic hydroxysulfate green rust, a potential electron acceptor for SRB activity  

Science.gov (United States)

Microbiological reduction of a biogenic sulfated green rust (GR2(SO42-)), was examined using a sulfate reducing bacterium ( Desulfovibrio alaskensis). Experiments investigated whether GR2(SO42-) could serve as a sulfate source for D. alaskensis anaerobic respiration by analyzing mineral transformation. Batch experiments were conducted using lactate as the electron donor and biogenic GR2(SO42-) as the electron acceptor, at circumneutral pH in unbuffered medium. GR2(SO42-) transformation was monitored with time by X-ray diffraction (XRD), Transmission Mössbauer Spectroscopy (TMS), Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS), Transmission Electron Microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS). The reduction of sulfate anions and the formation of iron sulfur mineral were clearly identified by XPS analyses. TMS showed the formation of additional mineral as green rust (GR) and vivianite. XRD analyses discriminated the type of the newly formed GR as GR1. The formed GR1 was GR1(CO32-) as indicated by DRIFTS analysis. Thus, the results presented in this study indicate that D. alaskensis cells were able to use GR2(SO42-) as an electron acceptor. GR1(CO32-), vivianite and an iron sulfur compound were formed as a result of GR2(SO42-) reduction by D. alaskensis. Hence, in environments where geochemical conditions promote biogenic GR2(SO42-) formation, this mineral could stimulate the anaerobic respiration of sulfate reducing bacteria.

Zegeye, Asfaw; Huguet, Lucie; Abdelmoula, Mustapha; Carteret, Cédric; Mullet, Martine; Jorand, Frédéric

2007-11-01

218

A new role for sulfur in arsenic cycling.  

Science.gov (United States)

Sulfur and arsenic often coexist in the environment and share similar microbial redox transformations. We examined the effects of sulfide on aerobic arsenite oxidation in alkaline lake water samples and in laboratory enrichment cultures. Significant arsenite oxidation occurred only in treatments with bacteria present, and production of arsenate was greatly enhanced by the addition of sulfide or thiosulfate. IC-ICP-MS analysis of samples showed that mono- and dithioarsenate formed in arsenite + sulfide amended lake water. Our data indicate that these two thioarsenic compounds are fairly stable in sterile alkaline solutions, but are transformed predominantly to arsenate when bacteria are present. Enrichment culture experiments suggest that sulfur-oxidizing bacteria use free or arsenic-bound sulfur as a growth substrate and directly or indirectly transform arsenite and thioarsenates to arsenate during growth. Increases in cell density resulted in more rapid conversion of arsenite and thioarsenates. The rate and extent of these processes appearto be controlled bythe concentration of bacteria and the ratio of reduced sulfur to arsenite present. Sulfur-driven arsenite oxidation and microbial thioarsenate transformation may be important biogeochemical processes in the arsenic cycle of our study site (Mono Lake, CA, USA) and other alkaline environments as well. PMID:18350879

Fisher, Jenny C; Wallschläger, Dirk; Planer-Friedrich, Britta; Hollibaugh, James T

2008-01-01

219

Geochemistry of sulfur in the Florida Everglades; 1994 through 1999  

Science.gov (United States)

In this report, we present data on the geochemistry of sulfur in sediments and in surface water, groundwater, and rainwater in the Everglades region in south Florida. The results presented here are part of a larger study intended to determine the roles played by the cycling of carbon, nitrogen, phosphorus, and sulfur in the ecology of the south Florida wetlands. The geochemistry of sulfur in the region is particularly important because of its link to the production of toxic methylmercury through processes mediated by sulfate reducing bacteria. Sediment cores were collected from the Everglades Agricultural Area (EAA), Water Conservation Areas (WCAs) 1A and 2A, from Lake Okeechobee, and from Taylor Slough in the southern Everglades. Water collection was more widespread and includes surface water from WCAs 1A, 2A, 3A, 2B, the EAA, Taylor Slough, Lake Okeechobee, and the Kissimmee River. Groundwater was collected from The Everglades Nutrient Removal Area (ENR) and from WCA 2A. Rainwater was collected at two month intervals over a period of one year from the ENR and from WCA 2A. Water was analyzed for sulfate concentration and sulfate sulfur stable isotopic ratio (34S/32S). Sediment cores were analyzed for total sulfur concentration and/or for concentrations of sulfur species (sulfate, organic sulfur, disulfides, and acid volatile sulfides (AVS)) and for their stable sulfur isotopic ratio. Results show a decrease in total sulfur content (1.57 to 0.61 percent dry weight) with depth in two sediment cores collected in WCA 2A, indicating that there has been an increase in total sulfur content in recent times. A sediment core from the center of Lake Okeechobee shows a decrease in total sulfur content with depth (0.28 to 0.08 percent dry weight). A core from the periphery of the lake (South Bay) likewise shows a decrease in total sulfur content with depth (1.00 to 0.69 percent dry weight), however, the overall sulfur content is greater than that near the center at all depths. This suggests input of sulfur in recent times, especially near the lake margins. Sediments show a general decrease in sulfur concentration with depth, probably because of increases in sulfur input to the marshes in recent times. Regional differences in the concentrations and stable isotopic ratios of sulfate sulfur in surface water show that sulfur contamination to the northern Everglades likely originates from canals draining the EAA.

Bates, Anne L.; Orem, W. H.; Harvey, J. W.; Spiker, E. C.

2000-01-01

220

Draft Genome Sequence of the Sulfur-Oxidizing Bacterium “Candidatus Sulfurovum sediminum” AR, Which Belongs to the Epsilonproteobacteria  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Sulfur-oxidizing bacteria are common microorganisms in a variety of sulfide-rich environments. They play important roles in the global sulfur cycle on earth. Here, we present a high-quality draft genome sequence of a sulfur-oxidizing bacterium, “Candidatus Sulfurovum sediminum” strain AR, which belongs to the class Epsilonproteobacteria and dominated an enrichment culture from a marine sediment collected off Svalbard, within the Arctic Circle. Its genome contains genes for sulfur oxidatio...

Park, Soo-je; Ghai, Rohit; Marti?n-cuadrado, Ana-bele?n; Rodri?guez-valera, Francisco; Jung, Man-young; Kim, Jong-geol; Rhee, Sung-keun

2012-01-01

 
 
 
 
221

Sulfur Particles on the Early Earth  

Science.gov (United States)

Understanding the atmosphere of the early Earth during the Archean, the period of time approximately 4 - 2.45 billion years ago, is an important part of understanding the conditions under which life originated and developed. The presence of sulfur mass independent fractionation (S-MIF) in Archean sediments is thought to be evidence for an early anoxic atmosphere. Photolysis of sulfur dioxide (SO2) by UV light with ?MIF fractionation; however, sulfur must leave the atmosphere in at least two chemically different forms to preserve any S-MIF signature. It has been suggested that atmospheric reactions in a reducing atmosphere could favor S8 particles over sulfuric acid particles. Here we use aerosol mass spectrometry to probe the chemical composition of particles formed from reactions of sulfur dioxide under a range of atmospheric conditions. We find that S8 formation is enhanced in the presence of reducing species, such as H2 (with electrical discharge as the energy source for reaction) and CH4 (using UV light with wavelengths from 115-400 nm to initiate reaction). Additionally, organosulfur species are formed from the photochemical reaction of SO2 and CH4. These species could be important in the later Archean when methanogenic bacteria could provide a source of CH4 to the atmosphere. Implications for the early Earth are discussed.

Hasenkopf, C. A.; Dewitt, H.; Trainer, M. G.; Farmer, D.; Jimenez, J. L.; McKay, C. P.; Toon, O. B.; Tolbert, M. A.

2010-12-01

222

Separation of sulfur isotopes  

International Nuclear Information System (INIS)

Sulfur isotopes are continuously separated and enriched using a closed loop reflux system in which sulfur dioxide (SO_2) is reacted with sodium hydroxide (NaOH) or the like to form sodium hydrogen sulfite (NaHSO_3). Heavier sulfur isotopes are preferentially attracted to the NaHSO_3, and subsequently reacted with sulfuric acid (H_2SO_4) forming sodium hydrogen sulfate (NaHSO_4) and SO_2 gas which contains increased concentrations of the heavier sulfur isotopes. This heavy isotope enriched SO_2 gas is subsequently separated and the NaHSO_4 is reacted with NaOH to form sodium sulfate (Na_2SO_4) which is subsequently decomposed in an electrodialysis unit to form the NaOH and H_2SO_4 components which are used in the aforesaid reactions thereby effecting sulfur isotope separation and enrichment without objectionable loss of feed materials

1976-01-01

223

Marine Bacteria from Danish Coastal Waters Show Antifouling Activity against the Marine Fouling Bacterium Pseudoalteromonas sp. Strain S91 and Zoospores of the Green Alga Ulva australis Independent of Bacteriocidal Activity  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aims of this study were to determine if marine bacteria from Danish coastal waters produce antifouling compounds and if antifouling bacteria could be ascribed to specific niches or seasons. We further assess if antibacterial effect is a good proxy for antifouling activity. We isolated 110 bacteria with anti-Vibrio activity from different sample types and locations during a 1-year sampling from Danish coastal waters. The strains were identified as Pseudoalteromonas, Phaeobacter, and Vibrio...

Bernbom, Nete; Ng, Yoke Yin; Kjelleberg, Staffan; Harder, Tilmann; Gram, Lone

2011-01-01

224

Marine Bacteria from Danish Coastal Waters Show Antifouling Activity against the Marine Fouling Bacterium Pseudoalteromonas sp. Strain S91 and Zoospores of the Green Alga Ulva australis Independent of Bacteriocidal Activity?†  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aims of this study were to determine if marine bacteria from Danish coastal waters produce antifouling compounds and if antifouling bacteria could be ascribed to specific niches or seasons. We further assess if antibacterial effect is a good proxy for antifouling activity. We isolated 110 bacteria with anti-Vibrio activity from different sample types and locations during a 1-year sampling from Danish coastal waters. The strains were identified as Pseudoalteromonas, Phaeobacter, and Vibrio...

Bernbom, Nete; Ng, Yoke Yin; Kjelleberg, Staffan; Harder, Tilmann; Gram, Lone

2011-01-01

225

Green thunderstorms  

Science.gov (United States)

Many people around the world have observed green light apparently emanating from severe thunderstorms, but until recently there has been no scientific study of the phenomenon. Green thunderstorms have been observed from time to time in association with deep convection or severe weather events. Some skeptics who have not personally observed a green thunderstorm suggest that they are some kind of illusion. The existence of green thunderstorms has been objectively demonstrated by recording spectra of light from thunderstorms using a handheld spectrophotometer. During the spring and summer of 1995 and the spring of 1996 numerous storms were observed and spectra of the light emanating from these storms were recorded. Observations were made both at the ground and aboard research aircraft. Furthermore, time series of spectra were recorded as the observed color of some storms changed from dark blue to a bluish-green. Several hypotheses have been advanced to explain the occurrence of green light in connection with severe storms. Fankhauser gave some observational support to the belief that green light from thunderstorms is possible and believed that the source of the light is from the blue sky penetrating thin regions in the clouds. Fraser believes that light from the setting sun, in combination with the process of scattering by atmospheric molecules, creates the green light associated with severe weather and the thunderstorm acts only as a black backdrop. Unfortunately, no cloud illuminated by the sun is black and the green airlight produced by the Fraser theory is in reality overwhelmed by light reflected by the cloud. Often the unusual coloration has been attributed to hail or to reflection of light from foliage on the ground. The quantitative measurements made during the observation period fail to support these assumptions. We have observed thunderstorms to be green over ground that was not green and we have observed blue thunderstorms over ground that was green. Finally, Bohren believes that reddened sunlight in combination with filtering done by naturally blue-colored water creates green light. Given our observations, this is the most likely explanation for the green light. Our observations and calculations indicate that, depending on the microphysical parameters of the cloud, sunlight transmitted by the cloud may appear green.

Gallagher, Frank Woolsey, III

226

Green Glossary  

Science.gov (United States)

This seven page document provides a glossary of "green" terms that would be useful in any courses which cover sustainability topics. Terms touch on renewable energy, current issues relating to sustainability and environmentalism and a number of green technologies. This document may be downloaded in Microsoft Word Doc file format.

Wolf, Arlynne

2012-03-23

227

ADVANCED SULFUR CONTROL CONCEPTS  

Energy Technology Data Exchange (ETDEWEB)

Conventional sulfur removal in integrated gasification combined cycle (IGCC) power plants involves numerous steps: COS (carbonyl sulfide) hydrolysis, amine scrubbing/regeneration, Claus process, and tail-gas treatment. Advanced sulfur removal in IGCC systems involves typically the use of zinc oxide-based sorbents. The sulfides sorbent is regenerated using dilute air to produce a dilute SO{sub 2} (sulfur dioxide) tail gas. Under previous contracts the highly effective first generation Direct Sulfur Recovery Process (DSRP) for catalytic reduction of this SO{sub 2} tail gas to elemental sulfur was developed. This process is currently undergoing field-testing. In this project, advanced concepts were evaluated to reduce the number of unit operations in sulfur removal and recovery. Substantial effort was directed towards developing sorbents that could be directly regenerated to elemental sulfur in an Advanced Hot Gas Process (AHGP). Development of this process has been described in detail in Appendices A-F. RTI began the development of the Single-step Sulfur Recovery Process (SSRP) to eliminate the use of sorbents and multiple reactors in sulfur removal and recovery. This process showed promising preliminary results and thus further process development of AHGP was abandoned in favor of SSRP. The SSRP is a direct Claus process that consists of injecting SO{sub 2} directly into the quenched coal gas from a coal gasifier, and reacting the H{sub 2}S-SO{sub 2} mixture over a selective catalyst to both remove and recover sulfur in a single step. The process is conducted at gasifier pressure and 125 to 160 C. The proposed commercial embodiment of the SSRP involves a liquid phase of molten sulfur with dispersed catalyst in a slurry bubble-column reactor (SBCR).

Apostolos A. Nikolopoulos; Santosh K. Gangwal; William J. McMichael; Jeffrey W. Portzer

2003-01-01

228

Future Sulfur Dioxide Emissions  

Energy Technology Data Exchange (ETDEWEB)

The importance of sulfur dioxide emissions for climate change is now established, although substantial uncertainties remain. This paper presents projections for future sulfur dioxide emissions using the MiniCAM integrated assessment model. A new income-based parameterization for future sulfur dioxide emissions controls is developed based on purchasing power parity (PPP) income estimates and historical trends related to the implementation of sulfur emissions limitations. This parameterization is then used to produce sulfur dioxide emissions trajectories for the set of scenarios developed for the Special Report on Emission Scenarios (SRES). We use the SRES methodology to produce harmonized SRES scenarios using the latest version of the MiniCAM model. The implications, and requirements, for IA modeling of sulfur dioxide emissions are discussed. We find that sulfur emissions eventually decline over the next century under a wide set of assumptions. These emission reductions result from a combination of emission controls, the adoption of advanced electric technologies, and a shift away from the direct end use of coal with increasing income levels. Only under a scenario where incomes in developing regions increase slowly do global emission levels remain at close to present levels over the next century. Under a climate policy that limits emissions of carbon dioxide, sulfur dioxide emissions fall in a relatively narrow range. In all cases, the relative climatic effect of sulfur dioxide emissions decreases dramatically to a point where sulfur dioxide is only a minor component of climate forcing by the end of the century. Ecological effects of sulfur dioxide, however, could be significant in some developing regions for many decades to come.

Smith, Steven J.; Pitcher, Hugh M.; Wigley, Tom M.

2005-12-01

229

Acidophilic, Heterotrophic Bacteria of Acidic Mine Waters  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Obligately acidophilic, heterotrophic bacteria were isolated both from enrichment cultures developed with acidic mine water and from natural mine drainage. The bacteria were grouped by the ability to utilize a number of organic acids as sole carbon sources. None of the strains were capable of chemolithotrophic growth on inorganic reduced iron and sulfur compounds. All bacteria were rod shaped, gram negative, nonencapsulated, motile, capable of growth at pH 2.6 but not at pH 6.0, catalase and ...

1981-01-01

230

The Microworld of Marine-Bacteria  

DEFF Research Database (Denmark)

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

JÃ?RGENSEN, BB

1995-01-01

231

Microbial treatment of sulfur-contaminated industrial wastes.  

Science.gov (United States)

The present study evaluated the microbial removal of sulfur from a solid industrial waste in liquid culture under laboratory conditions. The study involved the use of two bacteria Acidithiobacillus ferrooxidans ATCC 53987 and Acidithiobacillus thiooxidans AZCT-M125-5 isolated from a Mexican soil. Experimentation for industrial waste biotreatment was done in liquid culture using 125-mL Erlenmeyer flasks containing 30 mL Starkey modified culture medium and incubated at 30°C during 7 days. The industrial waste was added at different pulp densities (8.25-100% w/v) corresponding to different sulfur contents from 0.7 to 8.63% (w/w). Sulfur-oxidizing activity of the strain AZCT-M125-5 produced 281 and 262 mg/g of sulfate and a sulfur removal of 60% and 45.7% when the pulp density was set at 8.25 and 16.5% (w/v), respectively. In comparison, the strain A. ferrooxidans ATCC 53987 showed a lower sulfur-oxidizing activity with a sulfate production of 25.6 and 12.7 mg/g and a sulfur removal of 6% and 2.5% at the same pulp densities, respectively. Microbial growth was limited by pulp densities higher than 25% (w/v) of industrial waste with minimal sulfur-oxidizing activity and sulfur removal. The rate of sulfur removal for Acidithiobacillus thioxidans AZCT-M125-5 and Acidithiobacillus ferrooxidans ATCC 53987 was 0.185 and 0.0159 mg S g(-1) h(-1) with a pulp density of 16.5% (w/v), respectively. This study demonstrated that Acidithiobacillus thiooxidans AZCT-M125-5 possesses a high sulfur-oxidizing activity, even at high sulfur concentration, which allows the treatment of hazardous materials. PMID:24171423

Gómez-Ramírez, Marlenne; Zarco-Tovar, Karina; Aburto, Jorge; de León, Roberto García; Rojas-Avelizapa, Norma G

2014-01-01

232

Green Alliance  

...Green Alliance You are here: Our work Green living Tower blocks Towering ambitions Visions of a greener, cleaner future often involve people living ...and working happily in tall, shining towers, saving space, reducing waste and maximising efficiency. Sadly though, the tower blocks of today are ... As a result, tower blocks present a significant challenge, and many high rise residential buildings lack even basic sustainability measures, such as ...Green Alliance has worked with residents in three London tower blocks and conducted a series of interviews with experts across the country, to ...

233

Green Alliance  

...Green Alliance You are here: Staff Rachel Cary staff Rachel Cary head of energy direct dial: 0207 630 4525 email: rcary@green-alliance....uk Rachel leads the Low Carbon Energy theme. She specialises in energy policy and is author of several influential reports, including recent ... Rachel is currently conducting a review of European energy policy. Prior to joining Green Alliance, Rachel worked for a number of ... Rachel holds an MSc in environmental technology from Imperial College London, and has a degree in physics from Manchester University. Recent ...

234

Green tea  

Science.gov (United States)

... breast cancer, prostate cancer, colon cancer, gastric cancer, lung cancer, solid tumor cancers and skin cancer related to exposure to sunlight. Some women use green tea to fight human papilloma virus ( ...

235

Sulfuric Acid on Europa  

Science.gov (United States)

Frozen sulfuric acid on Jupiter's moon Europa is depicted in this image produced from data gathered by NASA's Galileo spacecraft. The brightest areas, where the yellow is most intense, represent regions of high frozen sulfuric acid concentration. Sulfuric acid is found in battery acid and in Earth's acid rain. This image is based on data gathered by Galileo's near infrared mapping spectrometer.Europa's leading hemisphere is toward the bottom right, and there are enhanced concentrations of sulfuric acid in the trailing side of Europa (the upper left side of the image). This is the face of Europa that is struck by sulfur ions coming from Jupiter's innermost moon, Io. The long, narrow features that crisscross Europa also show sulfuric acid that may be from sulfurous material extruded in cracks. Galileo, launched in 1989, has been orbiting Jupiter and its moons since December 1995. JPL manages the Galileo mission for NASA's Office of Space Science, Washington DC. JPL is a division of the California Institute of Technology, Pasadena, CA.

1999-01-01

236

Green Alliance  

...Green Alliance You are here: People Associates Rebecca Willis associates Rebecca Willis associate Rebecca Willis is an independent researcher. Her work focuses on ... Before joining Green Alliance in 1998, Rebecca spent two years as a policy adviser at the European Parliament in Brussels, specialising in international ...civil society by Alastair Harper 27 January 2014 Community energy comes of age by Rebecca Willis 21 January 2014 The UK’s curious crusade against a new ...

237

Effects of sulfur forms on heavy metals bioleaching from contaminated sediments.  

Science.gov (United States)

The use of recyclable forms of sulfur will exclude the risk of sediment reacidification and reduce the cost of bioleaching process. Three different forms of sulfur (namely sulfur powder, prills and pieces) were used to examine the utilization and recycle of sulfur, used as energy substrate for sulfur-oxidizing bacteria (SOB) in the bioleaching of heavy metal-contaminated sediments. The results showed that despite their relatively smaller surface areas, the efficiency of metal bioleaching with sulfur prills and pieces were comparable to that with sulfur powder. After 13 days of bioleaching, 71-74% of Zn, 58-62% of Cu, and 22-31% of Cr could be leached from the sediments, respectively. During bioleaching, most of the oxidizable and reducible forms of metals were transformed to acid soluble, posing a favorable condition for final metals removal. Sulfur recycling experiments showed that the recovered sulfur prills and pieces were as the same effective in pH reduction as fresh sulfur, revealing the feasibility of eventual reuse of the recycled sulfur in the bioleaching process. Further studies are required to testify the performance of these recyclable forms of sulfur in future large-scale bioleaching reactor. PMID:19412854

Fang, D; Zhao, L; Zhou, L X; Shan, H X

2009-06-01

238

[Physiological and ecological effects of sulfur fertilization on soybean].  

Science.gov (United States)

A pot experiment with 3 levels of elemental sulfur (0, 30, and 60 mg S x kg(-1)) showed that sulfur fertilization on soybean increased the side roots number by 8.6% - 33.2%, root dry weight by 6.6% - 34.3%, root nodules number by 2.7% - 35.9% and dry weight by 13.0% - 75.7%, chlorophyll content by 0.4 - 3.9 unit, and yield per plant by 7.3% - 12.8%. Sulfur fertilization also increased the amount of soil bacteria, fungi and actinomycetes and the activities of peroxidase, urease, neutral phosphatase and polyphenoloxidase significantly. The effects of sulfur supply differed with its application rate, and 30 mg S x kg(-1) was more appropriate for getting high soybean yield. PMID:17330483

Zhao, Yanwen; Bi, Dongmei; Zhao, Quanzhi; Liu, Changzhen; Hu, Zhengyi

2006-12-01

239

Under sulfur's spell  

Science.gov (United States)

Thomas Rauchfuss marvels at the diversity of sulfur reactivity. Although it poisons most industrial catalysts, it adopts many forms in nature and takes on a variety of biological roles -- including that of a biocatalyst.

Rauchfuss, Thomas

2011-08-01

240

No sulfur flows on Io  

Science.gov (United States)

Physical and chemical properties of elemental sulfur are incompatible with the suggestion that the colored flows associated with volcanoes on Io are quenched unstable allotropes of sulfur. Either the volcanic flows are not sulfur, or some mechanism other than quenching is required to produce colored forms of sulfur in them. The properties of sulfur are unsuited to the production and survival of colored unstable allotropes on Io. The color of this object is probably due to some other material, possibly iron compounds.

Young, A. T.

1984-01-01

 
 
 
 
241

Fermentation, Hydrogen, and Sulfur Metabolism in Multiple Uncultivated Bacterial Phyla  

Energy Technology Data Exchange (ETDEWEB)

BD1-5, OP11, and OD1 bacteria have been widely detected in anaerobic environments, but their metabolisms remain unclear owing to lack of cultivated representatives and minimal genomic sampling. We uncovered metabolic characteristics for members of these phyla, and a new lineage, PER, via cultivation-independent recovery of 49 partial to near-complete genomes from an acetate-amended aquifer. All organisms were nonrespiring anaerobes predicted to ferment. Three augment fermentation with archaeal-like type II and III ribulose-1,5-bisphosphate carboxylase-oxygenase (RuBisCO) that couples adenosine monophosphate salvage with CO2 fixation, a pathway previously not described in Bacteria. Members of OD1 reduce sulfur and may pump protons using archaeal-type hydrogenases. For six organisms, the UGA stop codon is translated as tryptophan. All bacteria studied here may play previously unrecognized roles in hydrogen production, sulfur cycling, and fermentation of refractory sedimentary carbon.

Wrighton, Kelly C.; Thomas, Brian C.; Sharon, I.; Miller, Christopher S.; Castelle, Cindy; VerBerkmoes, Nathan C.; Wilkins, Michael J.; Hettich, Robert L.; Lipton, Mary S.; Williams, Kenneth H.; Long, Philip E.; Banfield, Jillian F.

2012-09-27

242

Quadruple sulfur isotope constraints on the origin and cycling of volatile organic sulfur compounds in a stratified sulfidic lake  

Science.gov (United States)

We have quantified the major forms of volatile organic sulfur compounds (VOSCs) distributed in the water column of stratified freshwater Fayetteville Green Lake (FGL), to evaluate the biogeochemical pathways involved in their production. The lake's anoxic deep waters contain high concentrations of sulfate (12-16 mmol L-1) and sulfide (0.12 ?mol L-1 to 1.5 mmol L-1) with relatively low VOSC concentrations, ranging from 0.1 nmol L-1 to 2.8 ?mol L-1. Sulfur isotope measurements of combined volatile organic sulfur compounds demonstrate that VOSC species are formed primarily from reduced sulfur (H2S/HS-) and zero-valent sulfur (ZVS), with little input from sulfate. Thedata support a role of a combination of biological and abiotic processes in formation of carbon-sulfur bonds between reactive sulfur species and methyl groups of lignin components. These processes are responsible for very fast turnover of VOSC species, maintaining their low levels in FGL. No dimethylsulfoniopropionate (DMSP) was detected by Electrospray Ionization Mass Spectrometry (ESI-MS) in the lake water column or in planktonic extracts. These observations indicate a pathway distinct from oceanic and coastal marine environments, where dimethylsulfide (DMS) and other VOSC species are principally produced via the breakdown of DMSP by plankton species.

Oduro, Harry; Kamyshny, Alexey; Zerkle, Aubrey L.; Li, Yue; Farquhar, James

2013-11-01

243

Bacteria Transformation  

Science.gov (United States)

Illustrates the beginning stages of gene cloning. This animation shows how plasmids become recombinant and are inserted into bacteria cells. This is the second of four animations detailing the gene cloning process. To begin at the beginning, see Making a Recombinant Plasmid. (To see the next animation, go to Making a Gene Library.)

244

Green times  

International Nuclear Information System (INIS)

The authors, founding members of the ''Green Party'' have in mind to make a very personal contribution to a better understanding of the present political situation which, although it seems to have reached a deadlock, still offers positive chances and prospects. New approaches in policy are mentioned which may help to overcome the present state of resignation of many adolescents and adults. Among other things, they describe themselves setting out for new pathways, the ''Greens'' in Parliament, prospect for the future, opportunities of the ecologically oriented economic policy. Finally, they call upon the reader to think and develop further under the motto ''What we all can do''. (HSCH)

1982-01-01

245

Production of sulfuric acid and installation therefor  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the production of sulfuric acid by (a) oxidizing a sulfurous material with an oxidant to obtain sulfur dioxide, (b) catalytically oxidizing this with oxygen to obtain sulfur trioxide and (c) producing sulfuric acid and a waste gas, at least part of the waste gas is recycled to the first step. The fabrication of sulfuric acid consists of: (a) producing sulfur dioxide from a sulfur based material and an oxidant; (b) converting catalytically the sulfur dioxide into trioxide in a catalytic con...

Arpentinier, Philippe; Dumont, Marie-noe?lle; Kalitventzeff, Boris

1998-01-01

246

Not everything green has green  

International Nuclear Information System (INIS)

Last week (March 2009) Slovak government extended the preferential treatment of renewable energy. Companies that will produce electricity from biomass, water, wind, solar and underground thermal springs, have guaranteed that they will receive a decently paid at least the next 15 years. It promises them a new government bill on the promotion of renewable energy. So far, the State guaranteed the purchase of green power for only one year in advance. And because it is more expensive than electricity from coal or uranium, green investment firms feared. Fifteen guarantees give assurance. The government will guarantee only purchase green electricity, but also biomethane to produce heat. So, who wants an ordinary agrarian biogas from waste and adjust to such a gas. Slovak gas industry will have to buy it into its network. Biomethane is not in domestic terms only on paper.

2009-03-26

247

Green Leaders  

Science.gov (United States)

More and more people are viewing the world through green-tinted glasses, and those ideas about making school and university facilities more environmentally friendly suddenly are appearing to be prudent and responsible. Among the groups that have been advocating for environmentally friendly school design for years are the Collaborative for High…

Kennedy, Mike

2008-01-01

248

Being green  

Being green What can you do to be more environmentally conscious? Find out here Manage your waste properly How to deal with waste responsibly and legally. You could be fined if you do not use an authorised person to take away your waste. * Household waste * Fly-tipping   Save water Advice for…

249

Sodium-sulfur thermal battery  

Energy Technology Data Exchange (ETDEWEB)

This paper discusses a sodium-sulfur thermal battery for generating electrical energy at temperatures above the melting point of sodium metal and sulfur. It comprises a sodium electrode comprising sodium metal; a sulfur electrode comprising sulfur; and a separator located between the sodium and sulfur electrodes. The separator having sufficient porosity to allow preliminary migration of fluid sodium metal and fluid sulfur and fluid sodium polysulfides therethrough during operation of the thermal battery to form a mixed polysulfides electrolyte gradient within the separator.

Ludwig, F.A.

1990-12-11

250

Creating low sulfur diesel  

International Nuclear Information System (INIS)

The paper focuses on the importance of investing in flexible refinery systems which are able to cope even when more and more stringent legislation demands lower and lower levels of sulfur in diesel fuel. Apart from achieving the required low levels of sulfur, the system for producing the fuel should also be tailored to allow optimum and well-timed investment of resources to take advantage of market opportunities. The efficient and cost-effective route to producing ULSD (ultra low sulfur diesel) needs to take into account many factors (e.g. origin of the crude, feedstock variability, hydrogen supply, etc.). Axens North America has developed a new integrated approach which achieves the maximum Total Performance in Hydrotreating (TPH) from all these factors. The component parts of the Axens system are described. The new system provides a highly cost-effective approach for sustained production of ULSD

2002-03-01

251

Discrimination of Pigments of Microalgae, Bacteria and Yeasts Using Lightweight Handheld Raman Spectrometers: Prospects for Astrobiology  

Science.gov (United States)

Handheld Raman instrumentation with 532 nm lasers can be used to distinguish carotenoids of autotrophic microalgae, purple sulfur bacteria, halophilic Archaea and pigmented yeasts. Pigments are proposed as biomarkers for astrobiology of Mars.

Jehlicka, J.; Osterrothova, K.; Nedbalova, L.; Gunde-Cimerman, N.; Oren, A.

2014-06-01

252

Membrane damage of bacteria by silanols treatment  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english Antimicrobial action of silanols, a new class of antimicrobials, was investigated by transmission electron microscopy and fluorescent dye studies. Gram-negative bacteria, Escherichia coli and Pseudomonas aeruginosa and Gram-positive bacteria, Staphylococcus aureus and Enterococcus faecalis were trea [...] ted by silanols at concentration of less than 0.2 wt% for one hour. Membrane damage of the bacteria by the silanol treatment was clearly observed by transmission electron microscopy. Separation of the cytoplasmic membrane from the outer membrane for E. coli and disorganized cytoplasmic membrane of the Gram-positive bacteria were observed when compared to the control. Fluorescent dyes, green-fluorescent nucleic acid stain (Syto 9) and the red-fluorescent nucleic acid stain (Propidium iodide), were used to monitor membrane damage of the bacteria by Confocal microscopy and Spectrophotometer. A reduction of the green fluorescent emission was detected for silanol treated bacteria indicating membrane damage of the bacteria and supporting the hypothesis that their viability loss may be due to their membrane damage analogus to alcohols

Kim, Yun-mi; Farrah, Samuel; Baney, Ronald H.

253

Green Alliance  

... Contact Hannah Kyrke-Smith for more details. Introducing... Green Alliance's new events co-ordinator Emily Crawley comes with great credentials for running sustainable events, having worked previously at Sustain and on energy efficiency events and projects at the consultancy SE2.   Follow us on   Subscribe to enews If you ... by Matthew Spencer 11 February 2014 Why a non-binding renewable energy target could mean more power to the EU by Clive Bates 6 February 2014 Why targets alone won't build a green economy by Jonny Hazell 3 February 2014 Why politics really needs civil society by Alastair ...Harper 27 January 2014 Community energy comes of age by Rebecca Willis 21 January 2014 The UK’s curious crusade against a new renewable energy target by Matthew Spencer 2 January 2014 Let’s follow Germany with a renewable gas strategy instead of fracking by Dr Bruce Tofield News 13 February 2014 Sky News:...

254

Green WSUS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The new era of information and communication technology (ICT) calls for a greater understanding of the environmental impacts of recent technology. With increasing energy cost and growing environmental concerns, green IT is receiving more and more attention. Network and system design play a crucial role in both computing and telecommunication systems. Significant part of this energy cost goes to system update by downloading regularly patches and bug fixes to solve security pr...

Kadry, Seifedine; Joumaa, Chibli

2012-01-01

255

Metabolomic study of Chilean biomining bacteria Acidithiobacillus ferrooxidans strain Wenelen and Acidithiobacillus thiooxidans strain Licanantay  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this study, we present the first metabolic profiles for two bioleaching bacteria using capillary electrophoresis coupled with mass spectrometry. The bacteria, Acidithiobacillus ferrooxidans strain Wenelen (DSM 16786) and Acidithiobacillus thiooxidans strain Licanantay (DSM 17318), were sampled at different growth phases and on different substrates: the former was grown with iron and sulfur, and the latter with sulfur and chalcopyrite. Metabolic profiles were scored from planktonic and sess...

Marti?nez, Patricio; Ga?lvez, Sebastia?n; Ohtsuka, Norimasa; Budinich, Marko; Corte?s, Mari?a Paz; Serpell, Cristia?n; Nakahigashi, Kenji; Hirayama, Akiyoshi; Tomita, Masaru; Soga, Tomoyoshi; Marti?nez, Servet; Maass, Alejandro; Parada, Pilar

2013-01-01

256

Green Gold  

International Nuclear Information System (INIS)

The main purpose of this work is to offer a general panoramic of the processes or experiences pilot that are carried out in the Project Green Gold, as strategy of environmental sustainability and organizational invigoration in Choco, especially in the 12 communities of the municipalities of Tado and Condoto. It is also sought to offer a minimum of information on the techniques of handmade production and to show the possibilities to carry out in a rational way the use and use of the natural resources. The Project Green Gold is carried out by the Corporation Green Gold (COV) and co-financed with resources of international and national character, the intervention of the financial resources it achievement mainly for the use of clean processes in the extraction stages and metals benefit. The project is centered primarily in the absence of use of products or toxic substances as the mercury, fair trade, organizational invigoration, execution of 11 approaches and certification of the metals Gold and Platinum. The COV, it has come executing the proposal from the year 2001 with the premise of contributing to the balance between the rational exploitation of the natural resources and the conservation of the environment in the Choco. In the project they are used technical handmade characteristic of the region framed inside the mining activity and production activities are diversified in the productive family units. Those producing with the support of entities of juridical character, specify the necessary game rules for the extraction and products commercialization

2004-01-01

257

Biotic and abiotic carbon to sulfur bond cleavage. Final report  

Energy Technology Data Exchange (ETDEWEB)

The microbial desulfurization of organosulfur compounds occurs by unprecedented and largely unexplored biochemical processes. A study of such biotic desulfurizations can be expected to give rise to new and useful chemistry and enzymology. The potential value of understanding and harnessing these processes is seen in relation to the need for methods for the removal of organically bound sulfur from coal and the degradation of organic sulfur-containing pollutants. This research effort has been directed towards an examination of desulfurization ability in well characterized microorganisms, the isolation of bacteria with desulfurization ability from natural sources, the characterization and mechanistic evaluation of the observed biocatalytic processes, the development of biomimetic synthetic organic chemistry based on biotic desulfurization mechanisms and the design and preparation of improved coal model compounds for use in microbial selection processes. A systematic approach to studying biodesulfurizations was undertaken in which organosulfur compounds have been broken down into classes based on the oxidation state of the sulfur atom and the structure of the rest of the organic material. Microbes have been evaluated in terms of ability to degrade organosulfur compounds with sulfur in its sulfonic acid oxidation state. These compounds are likely intermediates in coal desulfurization and are present in the environment as persistent pollutants in the form of detergents. It is known that oxygen bonded to sulfur lowers the carbon-sulfur bond energy, providing a thermodynamic basis for starting with this class of compounds.

Frost, J.W.

1994-05-01

258

Regeneration of waste sulfuric acid  

Energy Technology Data Exchange (ETDEWEB)

To meet the increasing need of high-octane-number gasoline in Japan today, four sulfuric-acid-process alkylaters have recently been constructed. This construction has increased the importance of disposing of waste sulfuric acid. This report describes the present status of Japan's sulfuric acid industry, focusing on applicable ways of regenerating waste sulfuric acid. Japan's yield of sulfuric acid has been holding almost level at an annual rate of about 650 tons for the past ten years. The report gives a table of yearly changes in the production ratio by raw material and the operation rate of sulfuric acid plants. The report also gives an outline of the reaction of waste sulfuric acid extracted from an alkylater in each process and a partial description of the theory of reaction in the sulfuric acid production process using nitric acid. The report also deals with low-temperature active catalysts and high-temperature durable catalysts and describes a device to regenerate sulfuric acid from waste sulfuric acid and a device to produce sulfuric acid from refined gas, sulfide mineral, and sulfur. The report also roughly describes the newly-developed double-contact system and its features. (12 figs, 9 tabs, 12 refs)

Konishi, Hideki

1988-06-01

259

Green Corridor green energy partnerships  

Energy Technology Data Exchange (ETDEWEB)

The Green Corridor refers to 2 kilometres of multi-lane roadway in Windsor, Ontario, including the Ambassador Bridge crossing over the Detroit River to the United States. This bi-national trade route serves about 12,000 trucks per day and handles 40 per cent of Canada-US trade. The route passes through a large residential community with a concentrated business area, several schools and the University of Windsor campus. Residents are experiencing significant environmental impacts and are voicing concerns about quality of life which is compromised by pedestrian safety concerns, poor sightlines, and dominance of the transportation infrastructure. Negative impacts include soil, air, and noise pollution along with ecological stressors. The Corridor imparts a negative first impression for those arriving in Canada for trade, business and tourism. An aesthetic, educational and environmentally sound redevelopment of this Corridor would have impacts at the community, the city and the national levels. For these reasons, a sustainable environmental redevelopment of the designated Green Corridor was launched. The Green Corridor redevelopment involves the local creative, residential, educational, and business communities in re-imaging and transforming the currently disadvantaged environment. Green Corridor will achieve this through a series of publicly engaging research projects that combine environmental, social sciences research, art, and commercial development along the trade route. Community residents and visitors will experience a new conception of the urban landscape, shifting from a concrete mass to a regenerative green zone where landscape and environmental education are emphasized through an educational wetlands project at a local high school and provisions for environmental research at the University of Windsor. The redevelopment project serves as a model for proposed projects of wind and river turbines in which educational opportunities will be funded by research grants and partner donations while construction costs will be absorbed by public, industrial or commercial partners. The proposed nature bridge demonstrates the extent to which this collaborative exchange of ideas and shared responsibilities can work toward the development of viable, lasting contributions from the arts to a community. 1 ref., 4 figs.

Strickland, R. [Windsor Univ., ON (Canada). School of Visual Arts; Harding, N. [Noel Harding Studio, Toronto, ON (Canada)

2006-07-01

260

Green photonics  

International Nuclear Information System (INIS)

Photonics, the broad merger of electronics with the optical sciences, encompasses such a wide swath of technology that its impact is almost universal in our everyday lives. This is a broad overview of some aspects of the industry and their contribution to the ‘green’ or environmental movement. The rationale for energy conservation is briefly discussed and the impact of photonics on our everyday lives and certain industries is described. Some opinions from industry are presented along with market estimates. References are provided to some of the most recent research in these areas. (review article)

2012-02-01

 
 
 
 
261

Green Alliance  

... with: Chris Williamson MP, shadow minister for communities and local government, MP for Derby North Professor Anne Power, professor of social policy and head of LSE housing and communities Dave Allport, programme manager, Birmingham Energy Savers Toby Gale, Westbourne neighbourhood manager, Paddington Development Trust chaired by: Edward Hobson, deputy director, Green Alliance Existing high rise housing has the potential to be more resource efficient supporting better connected and more cohesive communities, and helping cities transform their environmental performance. But are existing policies designed to enable this? This event marked ...

262

Green Alliance  

... The Green conservatism advisory group is made up of both independent experts and party insiders:Lord Howard - patron Laura Sandys, MP for South Thanet and PPS to Greg Barker as minister for climate change - co-chair Zac Goldsmith, MP for Richmond Park Dan Byles, MP for North Warwickshire and Bedworth Ben Caldecott, head of government advisory, Bloomberg New Energy FInance Adrian Gahan, former energy and climate change policy adviser to the Conservative party Guy Newey, head of environment and energy, Policy Exchange Adam Corner, research associate, Cardiff University Peter Franklin,...

263

Predatory prokaryotes: Predation and primary consumption evolved in bacteria  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Two kinds of predatory bacteria have been observed and characterized by light and electron microscopy in samples from freshwater sulfurous lakes in northeastern Spain. The first bacterium, named Vampirococcus, is Gram-negative and ovoidal (0.6 ?m wide). An anaerobic epibiont, it adheres to the surface of phototrophic bacteria (Chromatium spp.) by specific attachment structures and, as it grows and divides by fission, destroys its prey. An important in situ predatory role can be inferred for ...

Guerrero, Ricardo; Pedro?s-alio?, Carlos; Esteve, Isabel; Mas, Jordi; Chase, David; Margulis, Lynn

1986-01-01

264

Green Manufacturing  

Energy Technology Data Exchange (ETDEWEB)

Green Manufacturing Initiative (GMI): The initiative provides a conduit between the university and industry to facilitate cooperative research programs of mutual interest to support green (sustainable) goals and efforts. In addition to the operational savings that greener practices can bring, emerging market demands and governmental regulations are making the move to sustainable manufacturing a necessity for success. The funding supports collaborative activities among universities such as the University of Michigan, Michigan State University and Purdue University and among 40 companies to enhance economic and workforce development and provide the potential of technology transfer. WMU participants in the GMI activities included 20 faculty, over 25 students and many staff from across the College of Engineering and Applied Sciences; the College of Arts and Sciences' departments of Chemistry, Physics, Biology and Geology; the College of Business; the Environmental Research Institute; and the Environmental Studies Program. Many outside organizations also contribute to the GMI's success, including Southwest Michigan First; The Right Place of Grand Rapids, MI; Michigan Department of Environmental Quality; the Michigan Department of Energy, Labor and Economic Growth; and the Michigan Manufacturers Technical Center.

Patten, John

2013-12-31

265

Green chemistry  

International Nuclear Information System (INIS)

A grand challenge facing government, industry, and academia in the relationship of our technological society to the environment is reinventing the use of materials. To address this challenge, collaboration from an interdisciplinary group of stakeholders will be necessary. Traditionally, the approach to risk management of materials and chemicals has been through inerventions intended to reduce exposure to materials that are hazardous to health and the environment. In 1990, the Pollution Prevention Act encouraged a new tact-elimination of hazards at the source. An emerging approach to this grand challenge seeks to embed the diverse set of environmental perspectives and interests in the everyday practice of the people most responsible for using and creating new materials--chemists. The approach, which has come to be known as Green Chemistry, intends to eliminate intrinsic hazard itself, rather than focusing on reducing risk by minimizing exposure. This chapter addresses the representation of downstream environmental stakeholder interests in the upstream everyday practice that is reinventing chemistry and its material inputs, products, and waste as described in the '12 Principles of Green Chemistry'

2004-01-01

266

Green chemistry  

International Nuclear Information System (INIS)

The depletion of world fossil fuel reserves and the involvement of greenhouse gases in the global warming has led to change the industrial and energy policies of most developed countries. The goal is now to reserve petroleum to the uses where it cannot be substituted, to implement renewable raw materials obtained from plants cultivation, and to consider the biodegradability of molecules and of manufactured objects by integrating the lifetime concept in their expected cycle of use. The green chemistry includes the design, development and elaboration of chemical products and processes with the aim of reducing or eliminating the use and generation of harmful compounds for the health and the environment, by adapting the present day operation modes of the chemical industry to the larger framework of the sustainable development. In addition to biofuels, this book reviews the applications of green chemistry in the different industrial processes in concern. Part 1 presents the diversity of the molecules coming from renewable carbon, in particular lignocellulose and the biotechnological processes. Part 2 is devoted to materials and treats of the overall available technological solutions. Part 3 focusses on functional molecules and chemical intermediates, in particular in sugar- and fats-chemistry. Part 4 treats of biofuels under the aspects of their production and use in today's technologies. The last part deals with the global approaches at the environmental and agricultural levels. (J.S.)

2006-01-01

267

Assimilation of sulfur from alkyl- and arylsulfonates by Clostridium spp.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Organisms able to utilize one of several alkyl- and arylsulfonates as sole source of sulfur under anoxic conditions were enriched. Three fermenting bacteria, all putative Clostridium spp., were isolated in pure culture. All three organisms had wide substrate ranges for alkylsulfonates, taurine and arylsulfonates, presumably due to three different enzyme systems. One organism, strain KNNDS (DSM 10612) was selected for further characterization. The organism was possibly a new Clostridium sp., w...

Denger, Karin; Cook, Alasdair M.

1997-01-01

268

Sulfur activation at Hiroshima  

International Nuclear Information System (INIS)

After the atomic bomb explosion in Hiroshima, Yamasaki and Sugimoto were able to measure the fast neutron activation of sulfur in the mastic holding insulators on electric poles (Appendix 5-2). Details of the sample collection and measurement procedure have been described by Hamada. The activation reaction 32S(n,p) 32P has a neutron energy threshold of about 2.5 MeV. The 32P decays by beta-particle emission with a half-life of 14.2 days. In 1958, Yamasaki revised his original data by correcting for self-absorption in the samples and by using new half-life data. The revised sulfur activation data were first compared by Kerr to calculated sulfur activation versus ground range using the one-dimensional, isotropic source output provided for Hiroshima by Preeg. A comparison similar to Kerr's of the measured activation data with calculations is shown. The results were discouraging. The transport calculation using the Preeg source is higher than the measured data by over a factor of two close to the hypocenter. Another discouraging aspect is the scatter in the measured sulfur data points. For example, there are points at larger ground ranges that have higher activities than smaller ground ranges. One normally expects the variation to be a rather smooth, nearly exponential decrease with distance. Because the sulfur activation is by high-energy neutrons and because the geometry of the insulators on the electric poles is simple enough to permit accurate calculations, good agreement between calculation and measurement would lend credence to the procedures being used to reassess the doses to the survivors. Fortunately, a number of developments led to better agreement. The Preeg source was an early, one-dimensional model of the Hiroshima bomb. Whalen and his colleagues at LANL made two-dimensional, coupled radiation and hydrodynamic calculations for the Hiroshima bomb that were better suited to its cylindrical symmetry. They provided an energy- and angle-dependent output of neutrons and gamma rays from the Hiroshima weapon that is used as the source term for the calculation of the free-field, air-over-ground, neutron, prompt gamma ray, and secondary radiation fields in the new dosimetry system (chapter 2,3 and 9). Furthermore, since the comparison in 1981, Hamada made additional corrections to the sulfur activation data. These corrections include a more complete analysis of the self-absorption of the samples, an analysis of their purity, revised locations, and an estimate of the uncertainty in the reported activities. The work reported here uses the two-dimensional output calculation of the Hiroshima explosion to calculate the sulfur activation and compares the results with Hamada's revision of the measurements. Because the axis of the bomb was not vertical when it exploded, the sulfur activation is not simply a function of ground range; it is a function of both the range and the azimuthal location of the insulator with respect to the bomb trajectory

1987-01-01

269

Structural basis for the oxidation of thiosulfate by a sulfur cycle enzyme  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Reduced inorganic sulfur compounds are utilized by many bacteria as electron donors to photosynthetic or respiratory electron transport chains. This metabolism is a key component of the biogeochemical sulfur cycle. The SoxAX protein is a heterodimeric c-type cytochrome involved in thiosulfate oxidation. The crystal structures of SoxAX from the photosynthetic bacterium Rhodovulum sulfidophilum have been solved at 1.75 ? resolution in the oxidized state and at 1.5 ? resolution in the dith...

Bamford, Vicki A.; Bruno, Stefano; Rasmussen, Tim; Appia-ayme, Corinne; Cheesman, Myles R.; Berks, Ben C.; Hemmings, Andrew M.

2002-01-01

270

Biogenesis of iron-sulfur clusters in mammalian cells: new insights and relevance to human disease  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Iron-sulfur (Fe-S) clusters are ubiquitous cofactors composed of iron and inorganic sulfur. They are required for the function of proteins involved in a wide range of activities, including electron transport in respiratory chain complexes, regulatory sensing, photosynthesis and DNA repair. The proteins involved in the biogenesis of Fe-S clusters are evolutionarily conserved from bacteria to humans, and many insights into the process of Fe-S cluster biogenesis have come from studies of model o...

Rouault, Tracey A.

2012-01-01

271

Stratospheric sulfur oxidation kinetics  

Energy Technology Data Exchange (ETDEWEB)

Oxidation of SO2 to H2SO4 in the atmosphere is believed to involve the reaction of SO3 with water. It is commonly assumed that this is an important step leading to homogeneous nucleation of H2SO4 aerosol particles. Heterogeneous chemistry on sulfuric acid aerosols regulate much of the ozone photochemistry in the lower stratosphere and are also believed to have significant effect on the climate. Understanding aerosol loading requires a detailed knowledge of the stratospheric sulfur budget, including its oxidation kinetics. Here we present results of a laboratory project studying a key step in the oxidation process, the homogeneous reaction between SO3 and H2O vapor. Kinetic measurements are performed in a high-pressure turbulent fast-flow reactor (fabricated at MIT) which minimizes heterogeneous loss of SO3 on reactorwalls. The rate of decay of SO3 and the appearance of H2SO4 is monitored in the presence of excess water vapor. Gas phase reactants and products are detected via an atmospheric pressure chemical ionization mass spectrometer which is coupled to the exit of the flow reactor. Sulfuric acid nucleation studies can also be performed using the turbulent flow reactor. Initial measurements using a particle detector (based on Mie scattering) showed that aerosol formation and particle size distribution are controlled by varying the SO3/H2O gas ratio and the reactor temperature. Results for the reaction SO3J+ H2O show a second order dependence in water vapor density and a strong negative temperature dependence. The results, measured in the range -30C to +95C, imply that an SO3.H2O adduct and/or a water dimer species is likely involved in the reaction mechanism. Results of recent theoretical calculations on the SO3 + H2O system also support the finding that two water molecules are involved. Implications for the gas phase production of sulfuric acid in the atmosphere will be discussed.

Jayne, J.T.; Worsnop, D.R.; Kolb, C.E. [Aerodyne Research, Inc., Billerica, MA (United States)] [and others

1995-12-31

272

Acidophilic sulfur disproportionation  

Science.gov (United States)

Bacterial disproportionation of elemental sulfur (S0) is a well-studied metabolism and is not previously reported to occur at pH values less than 4.5. In this study, a sediment core from an abandoned-coal-mine-waste deposit in Southwest Indiana revealed sulfur isotope fractionations between S0 and pyrite (?34Ses-py) of up to -35‰, inferred to indicate intense recycling of S0 via bacterial disproportionation and sulfide oxidation. Additionally, the chemistry of seasonally collected pore-water profiles were found to vary, with pore-water pH ranging from 2.2 to 3.8 and observed seasonal redox shifts expressed as abrupt transitions from Fe(III) to Fe(II) dominated conditions, often controlled by fluctuating water table depths. S0 is a common product during the oxidation of pyrite, a process known to generate acidic waters during weathering and production of acid mine drainage. The H2S product of S0 disproportionation, fractionated by up to -8.6‰, is rapidly oxidized to S0 near redox gradients via reaction with Fe(III) allowing for the accumulation of isotopically light S0 that can then become subject to further sulfur disproportionation. A mass-balance model for S0 incorporating pyrite oxidation, S0 disproportionation, and S0 oxidation readily explains the range of observed ?34Ses-py and emphasizes the necessity of seasonally varying pyrite weathering and metabolic rates, as indicated by the pore water chemistry. The findings of this research suggest that S0 disproportionation is potentially a common microbial process at a pH sulfur isotope fractionations, even in the absence of sulfate reduction.

Hardisty, Dalton S.; Olyphant, Greg A.; Bell, Jonathan B.; Johnson, Adam P.; Pratt, Lisa M.

2013-07-01

273

Efeito de extratos de própolis verde sobre bactérias patogênicas isoladas do leite de vacas com mastite / Effect of green propolis extracts on patogenic bacteria isolated from milk of cows with mastitis  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A sensibilidade, in vitro, de amostras de Staphylococcus aureus, Staphylococcus sp. coagulase negativos, Streptococcus agalactiae e bactérias do grupo dos coliformes, isoladas do leite de vacas com mastite, a diferentes extratos de própolis, na concentração de 100 mg/ml, foi avaliada pela técnica do [...] antibiograma em discos de papel de filtro com sobrecamada de meio de cultura. Os resultados mostraram que o extrato etanólico de própolis comercial, os extratos etanólico e, em menor proporção, o metanólico inibiram o crescimento das amostras de bactérias Gram-positivas, Staphylococcus aureus, Staphylococcus sp. coagulase negativos e Streptococcus agalactiae. Os extratos obtidos através da água, do acetato de etila e do clorofórmio não inibiram nenhuma amostra bacteriana, assim como os veículos etanol e metanol puros utilizados como controle. A bactéria Gram-negativa testada, do tipo coliforme, não apresentou sensibilidade a nenhum dos extratos. Verificaram-se diferenças significativas (p Abstract in english In vitro, the sensitivity to different propolis extracts, at a concentration of 100 mg/ml, of Staphylococcus aureus, Staphylococcus sp. coagulase negative, Streptococcus agalactiae and bacteria of the coliform group, isolated from the milk of cows with mastitis, was evaluated using the technique of [...] an agar disk diffusion with a medium doublelayer. The results showed that the commercial propolis, the ethanolic extract, and, in a minor proportion, the methanolic extract inhibited the growth of the Gram positive bacteria, Staphylococcus aureus, Staphylococcus sp. coagulase negative and Streptococcus agalactiae. The extracts obtained through water, etila acetate and chloroform did not inhibit any bacterial strains, nor did the pure ethanol and methanol vehicles that were utilized as controls. The Gram negative bacterium tested, from the coliform group, did not show sensitivity to any extract. Bacterial strains of the same species collected from different sources presented significant differences in sensitivity to the extracts (p

PINTO, Marcelo Souza; FARIA, José Eurico de; MESSAGE, Dejair; CASSINI, Sérvio Túlio Alves; PEREIRA, Carmen Silva; GIOSO, Marilú Martins.

274

Green business will remain green  

International Nuclear Information System (INIS)

It all started with two words. Climate change. The carbon dioxide trading scheme, which was the politicians' idea on solving the number one global problem, followed. Four years ago, when the project was begun, there was no data for project initiation. Quotas for polluters mainly from energy production and other energy demanding industries were distributed based on spreadsheets, maximum output and expected future development of economies. Slovak companies have had a chance to profit from these arrangements since 2005. Many of them took advantage of the situation and turned the excessive quotas into an extraordinary profit which often reached hundreds of million Sk. The fact that the price of free quotas offered for sale dropped basically to 0 in 2006 only proved that the initial distribution was too generous. And the market reacted to the first official measurements of emissions. Slovak companies also contributed to this development. However, when planning the maximum emission volumes for 2008-2012 period, in spite of the fact that actual data were available, their expectations were not realistic. A glance at the figures in the proposal of the Ministry of Environment is sufficient to realize that there will be no major change in the future. And so for many Slovak companies business with a green future will remain green for the next five years. The state decided to give to selected companies even more free space as far as emissions are concerned. The most privileged companies can expect quotas increased by tens of percent. (author)

2008-01-17

275

Green Alliance  

...Faye Scott, senior policy adviser, Green AllianceTony Travers, visiting professor, London School of EconomicsSimon Marsh, head of planning and regional policy, RSPBAlex Thomson, chief executive, LocalisDame Fiona Reynolds DBE, director general, National Trust chaired by: Peter Hetherington, Society Guardian and Town & Country Planning Association This debate analysed the prospects for environmental priorities under the localism agenda and in the light of forthcoming planning reforms.   kindly supported by ...   (chair) Peter Hetherington, Society Guardian and Town & Country Planning Association Peter Hetheringon, former regional affairs and northern editor of The Guardian, writes regularly for Society Guardian on local government, housing and  regeneration. He chaired the Town and Country Planning Association-serviced cross-party Connecting England Commission, continues to help lead work in this area  arguing for a more balance economy across England -  and is a ...

276

Green buildings  

... Advances in renewable energy technologies, such as a 'solar dye' for example, will certainly contribute greatly to the 'greening' of buildings and may someday lead to the widespread construction of buildings that far exceed the energy efficiency requirements set by policy-makers. Towards sustainable cities Beyond individual buildings or isolated developments, entire 'eco-cities' are currently being planned. Two of the most ambitious of these projects are located ... It called for explicit reference to the role of reduced VAT and other financial incentives in encouraging renovation works and to the need to train SMEs in techniques for energy-efficient renovation. The WWF is also critical of the current EPBD because it does not apply to most existing buildings, which constitute a majority of building stock. WWF  claims that most member states are only implementing the directive's ...

277

Isolation of an aerobic sulfur oxidizer from the SUP05/Arctic96BD-19 clade.  

Science.gov (United States)

Bacteria from the uncultured SUP05/Arctic96BD-19 clade of gamma proteobacterial sulfur oxidizers (GSOs) have the genetic potential to oxidize reduced sulfur and fix carbon in the tissues of clams and mussels, in oxygen minimum zones and throughout the deep ocean (>200?m). Here, we report isolation of the first cultured representative from this GSO clade. Closely related cultures were obtained from surface waters in Puget Sound and from the deep chlorophyll maximum in the North Pacific gyre. Pure cultures grow aerobically on natural seawater media, oxidize sulfur, and reach higher final cell densities when glucose and thiosulfate are added to the media. This suggests that aerobic sulfur oxidation enhances organic carbon utilization in the oceans. The first isolate from the SUP05/Arctic96BD-19 clade was given the provisional taxonomic assignment 'Candidatus: Thioglobus singularis', alluding to the clade's known role in sulfur oxidation and the isolate's planktonic lifestyle. PMID:22875135

Marshall, Katharine T; Morris, Robert M

2013-02-01

278

The green building envelope: vertical greening:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Planting on roofs and façades is one of the most innovative and fastest developing fields of green technologies with respect to the built environment and horticulture. This thesis is focused on vertical greening of structures and to the multi-scale benefits of vegetation. Vertical green can improve the environment in urban areas and is becoming a key design consideration in modern building developments. Vertical greening of structures offers large surfaces with vegetation and at the same tim...

Ottele?, M.

2011-01-01

279

Sulfur-Containing Glycomimetics  

Science.gov (United States)

Sugars with heteroatoms other than oxygen in the ring are unusual but highly interesting relatives of "normal" sugars. In particular, 4-thiofuranoses as well as 5-thiopyranoses have attracted considerable attention. Side by side with their counterparts with nitrogen in the ring, the iminosugars, these thiosugars feature exciting challenges for both the chemists synthesizing them and the biologists investigating their biological properties as glycomimetics. This chapter is aimed at giving an introduction to the world of sugars with sulfur in the ring, their syntheses as well as their chemical and biochemical properties as known to date.

Steiner, Andreas; Stütz, Arnold; Wrodnigg, Tanja

280

Beating sulfur sensitivity  

Energy Technology Data Exchange (ETDEWEB)

The paper explains the value of correct choice of catalyst for a butadiene selective hydrogenation unit; in particular sulfur-tolerant catalysts which minimise the need for frequent regeneration and therefore minimise production losses. As a consequence, a net increase in the benefits of the HF alkylation unit is achieved. The article explains selective hydrogenation chemistry, experimental apparatus, experimental procedure and experimental results. Other sub-headings are: activity and catalyst properties; industrial performance; economical evaluation. There was good agreement between the laboratory results and the full-scale industrial results.

Rabello, C.R.K.; Caldeira, A.C.C.; Souza, G.L.M. [PETROBRAS Research Center (Brazil)

2000-06-01

 
 
 
 
281

Blue-green algae  

Science.gov (United States)

... likely to be contaminated by bacteria, liver poisons (microcystins) produced by certain bacteria, and heavy metals. Choose ... of contaminants, such as liver-damaging substances called microcystins, toxic metals, and harmful bacteria, are POSSIBLY SAFE ...

282

Isolation and characterization of bacteria on the drainage water from Ratones mine and its behaviour on pyrite; Aislamiento y caracterizacion de bacterias en aguas de la mina de ratones y su comportamiento con pirita  

Energy Technology Data Exchange (ETDEWEB)

This paper describes some of the studies made about iron and sulfur oxidizing bacteria on the drainage water from Ratones mine. Different liquid and solid media were utilized as well as some energy sources, ferrous sulphate, thiosulfate and sulfur. Some experiment were al so realized on museum grade pyrite aimed at determining the possibilities of applying the mentioned bacteria on the leaching of pyrite and subsequently on the leaching of uranium ores. (Author) 27 refs.

Merino, J. L.; Saez, R. M.

1974-07-01

283

Process for removing sulfur from sulfur-containing gases  

International Nuclear Information System (INIS)

This patent describes a process for reducing the level of sulfur dioxide in a sulfur dioxide- containing gas. It comprises preparing an aqueous slurry comprising a calcium alkali together with a calcium-reactive silica or alumina, the calcium alkali and calcium-reactive silica or alumina being introduced into the slurry in a form consisting essentially of a high calcium fly ash, which are present in amounts sufficient to allow for the formation of a sulfur dioxide-absorbing component which includes a calcium silicate or calcium aluminate; heating the slurry to a temperature between about 50 degrees and 200 degrees C. for between about 0.1 and about 24 hours to facilitate in the formation of the sulfur dioxide-absorbing component; contacting the gas with the slurry in a manner sufficient to allow for the absorption of sulfur dioxide by the absorbing component; and separating the absorbing component in the form of spent solids from the gas

1989-12-08

284

Growth of Acidithiobacillus Ferrooxidans ATCC 23270 in Thiosulfate Under Oxygen-Limiting Conditions Generates Extracellular Sulfur Globules by Means of a Secreted Tetrathionate Hydrolase  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Production of sulfur globules during sulfide or thiosulfate oxidation is a characteristic feature of some sulfur bacteria. Although their generation has been reported in Acidithiobacillus ferrooxidans, its mechanism of formation and deposition, as well as the physiological significance of these globules during sulfur compounds oxidation, are currently unknown. Under oxygen-sufficient conditions (OSC), A. ferrooxidans oxidizes thiosulfate to tetrathionate, which accumulates in the culture medi...

Beard, Simo?n; Paradela, Alberto; Albar, Juan P.; Jerez, Carlos A.

2011-01-01

285

Sulfur in Cometary Dust  

Science.gov (United States)

The computer-intensive project consisted of the analysis and synthesis of existing data on composition of comet Halley dust particles. The main objective was to obtain a complete inventory of sulfur containing compounds in the comet Halley dust by building upon the existing classification of organic and inorganic compounds and applying a variety of statistical techniques for cluster and cross-correlational analyses. A student hired for this project wrote and tested the software to perform cluster analysis. The following tasks were carried out: (1) selecting the data from existing database for the proposed project; (2) finding access to a standard library of statistical routines for cluster analysis; (3) reformatting the data as necessary for input into the library routines; (4) performing cluster analysis and constructing hierarchical cluster trees using three methods to define the proximity of clusters; (5) presenting the output results in different formats to facilitate the interpretation of the obtained cluster trees; (6) selecting groups of data points common for all three trees as stable clusters. We have also considered the chemistry of sulfur in inorganic compounds.

Fomenkova, M. N.

1997-01-01

286

Leaching of Zinc Sulfide by Thiobacillus ferrooxidans: Bacterial Oxidation of the Sulfur Product Layer Increases the Rate of Zinc Sulfide Dissolution at High Concentrations of Ferrous Ions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper reports the results of leaching experiments conducted with and without Thiobacillus ferrooxidans at the same conditions in solution. The extent of leaching of ZnS with bacteria is significantly higher than that without bacteria at high concentrations of ferrous ions. A porous layer of elemental sulfur is present on the surfaces of the chemically leached particles, while no sulfur is present on the surfaces of the bacterially leached particles. The analysis of the data using the shr...

Fowler, T. A.; Crundwell, F. K.

1999-01-01

287

EPA Green Buildings  

Science.gov (United States)

The Environmental Protection Agency's site contains a wealth of information on green guilding: green-built schools, residences, and office buildings. This site also describes what EPA is doing to green its own buildings. Topics such as energy efficiency, indoor environment, and sustainable development are covered on the Green Buildings website.

2008-09-12

288

Centrifugal enrichment of sulfur isotopes  

International Nuclear Information System (INIS)

This work contains the results of the research for the complete cycle of the centrifuge enrichment process of all sulfur isotopes. As a result of this work there was obtained, and made available (by centrifuge enrichment process), for the first time hundreds of grams of all the isotopes of sulfur to high enrichment. (author)

2014-02-01

289

Process for preparing sulfur granules  

Energy Technology Data Exchange (ETDEWEB)

This invention relates to a process for the preparation of sulfur granules, in which in a granulation zone a sulfur melt is, with the aid of at least one feeding device, supplied in an upward direction into a bed of of sulfur nuclei. These nuclei are kept separate from each other and are contacted with a gas. The process is characterized in that a sulfur melt having a temperature of at least 5/sup 0/C above the crystallization temperature is introduced into a bed of sulfur nuclei having a temperature of 30-70/sup 0/C. The bed is fluidized with a gas, and the melt, after having left the feeding device, is contacted with a powerful gas stream having a temperature about equal to the temperature of the melt and a velocity of at least 100 m/s, in such an amount that the mass ratio of the gas stream to the sulfur melt is between 0.1 : 1 and 0.6 : 1. The sulfur granules formed are continuously discharged from the granulation zone. The process provides a more efficient production of sulfur granules having improved properties and reduces agglomeration of granules in the bed.

Slangen, H.J.M.; Hoek, C.

1988-09-20

290

Sulfur redox chemistry governs diurnal antimony and arsenic cycles at Champagne Pool, Waiotapu, New Zealand  

Science.gov (United States)

Champagne Pool, a sulfidic hot spring in New Zealand, exhibits distinct diurnal variations in antimony (Sb) and arsenic (As) concentrations, with daytime high and night-time low concentrations. To identify the underlying mobilization mechanisms, five sites along the drainage channel of Champagne Pool were sampled every 2 h during a 24 h period. Temporal variations in elemental concentrations and Sb, As, and sulfur (S) speciation were monitored in the discharging fluid. Total trace element concentrations in filtered and unfiltered samples were analyzed using ICP-MS, and Sb, As and S species were determined by IC-ICP-MS. Sulfur speciation in the drainage channel was dominated by thiosulfate and sulfide at night, while sulfate dominated during the day. The distinct diurnal changes suggest that the transformations are caused by phototrophic sulfur-oxidizing bacteria. These bacteria metabolize thiosulfate and sulfide in daylight to form sulfate and, as suggested by modeling with PhreeqC, elemental sulfur. Sulfide consumption during the day results in undersaturation of antimony sulfides, which triggers the additional release of dissolved Sb. For As, diurnal cycles were much more pronounced in speciation than in total concentrations, with di- and trithioarsenate forming at night due to excess sulfide, and monothioarsenate forming from arsenite and elemental sulfur during the day. Sulfur speciation was thus found to control Sb and As in terms of both solubility and speciation.

Ullrich, Maria K.; Pope, James G.; Seward, Terry M.; Wilson, Nathaniel; Planer-Friedrich, Britta

2013-07-01

291

The purification of elemental sulfur  

Energy Technology Data Exchange (ETDEWEB)

Sulfur has been purified by a dynamic pyrolysis procedure that takes into account the unique viscosity-temperature relationship of the liquid. An apparatus is described that incorporates gas-bubbling and rocking to overcome diffusion-limited kinetics. For the first time, a mechanism is proposed for the pyrolytic purification of sulfur based upon Carsul formation and the H{sub 2}S{leftrightarrow}H{sub 2}S{sub {ital x}} equilibrium. Infrared methods are delineated for qualitative analysis and quantitative estimates of anion contaminants, including the omnipresent hydrocarbon impurities. Our purified sulfur has a total carbon, oxygen, and hydrogen impurity level of {lt}10 {mu}g/g.

Susman, S.; Rowland, S.C.; Volin, K.J. (Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States))

1992-06-01

292

Sulfur, ultraviolet radiation, and the early evolution of life  

Science.gov (United States)

The present biosphere is shielded from harmful solar near ultraviolet (UV) radiation by atmospheric ozone. It is suggested that elemental sulfur vapor could have played a similar role in an anoxic, ozone-free, primitive atmosphere. Sulfur vapor would have been produced photochemically from volcanogenic SO2 and H2S. It is composed of ring molecules, primarily S8, that absorb strongly throughout the near UV, yet are expected to be relatively stable against photolysis and chemical attack. It is also insoluble in water and would thus have been immune to rainout or surface deposition over the oceans. Since the concentration of S8 in the primitive atmosphere would have been limited by its saturation vapor pressure, surface temperatures of 45 C or higher, corresponding to carbon dioxide partial pressures exceeding 2 bars, are required to sustain an effective UV screen. A warm, sulfur-rich, primitive atmosphere is consistent with inferences drawn from molecular phylogeny, which suggest that some of the earliest organisms were thermophilic bacteria that metabolized elemental sulfur.

Kasting, J. F.; Zahnle, K. J.; Pinto, J. P.; Young, A. T.

1989-01-01

293

Effect of operating parameters on sulfide biotransformation to sulfur.  

Science.gov (United States)

A laboratory-scale bioreactor with polyethylene semi-soft packing was constructed and utilized to determine the efficiency of sulfide biotransformation to sulfur under various operating parameters. Sodium sulfide dissolved in tap water was pumped into the bioreactor as sulfide for biological desulfurization. The sulfide, sulfur and sulfate-S in the effluent and the sulfide purged as gas-phase H2S were determined to investigate the effects of operating parameters, such as pH, DO, hydraulic retention time (HRT), temperature and salinity, on the sulfide oxidation products. The activity of bacteria was highest at pH 7.8-8.2. The maximal sulfide removal load was 7.25 kg/(m3 x day), with a 322.07 mg/L influent sulfide concentration and 4.80 mg/L DO. The increase of DO value corresponds to a decrease in the sulfur yield. The reactor had the highest sulfide removal load and sulfur yield at 2.55 mg/L DO. HRT had little effect on desulfurization efficiency when the sulfide removal load was kept constant. The most effective desulfurization temperature was 33 degrees C. The sulfide removal load decreased from 2.85 to 0.51 kg/(m3 x day) with increasing salinity from 0.5% to 2.5% (m/m). PMID:24649672

Liu, Weiguo; Liang, Cunzhen; Chen, Jiaqing; Zhu, Ling

2013-12-01

294

Physiology of phototrophic iron(II)-oxidizing bacteria: implications for modern and ancient environments.  

Science.gov (United States)

Phototrophic iron(II) [Fe(II)]-oxidizing bacteria are present in modern environments and evidence suggests that this metabolism was present already on early earth. We determined Fe(II) oxidation rates depending on pH, temperature, light intensity, and Fe(II) concentration for three phylogenetically different phototrophic Fe(II)-oxidizing strains (purple nonsulfur bacterium Rhodobacter ferrooxidans sp. strain SW2, purple sulfur bacterium Thiodictyon sp. strain F4, and green sulfur bacterium Chlorobium ferrooxidans strain KoFox). While we found the overall highest Fe(II) oxidation rates with strain F4 (4.5 mmol L(-1) day(-1), 800 lux, 20 degrees C), the lowest light saturation values [at which maximum Fe(II) oxidation occurred] were determined for strain KoFox with light saturation already below 50 lux. The oxidation rate per cell was determined for R. ferrooxidans strain SW2 to be 32 pmol Fe(II) h(-1) per cell. No significant toxic effect of Fe(II) was observed at Fe(II) concentrations of up to 30 mM. All three strains are mesophiles with upper temperature limits of c. 30 degrees C. The main pigments were identified to be spheroidene, spheroidenone, OH-spheroidenone (SW2), rhodopinal (F4), and chlorobactene (KoFox). This study will improve our ecophysiological understanding of iron cycling in modern environments and will help to evaluate whether phototrophic iron oxidizers may have contributed to the formation of Fe(III) on early earth. PMID:18811650

Hegler, Florian; Posth, Nicole R; Jiang, Jie; Kappler, Andreas

2008-11-01

295

GREEN MARKETING - AN OVERVIEW  

Directory of Open Access Journals (Sweden)

Full Text Available In today's business world environmental issues plays an important role in marketing. All most all the governments around the world have concerned about green marketing activities that they have attempted to regulate them. There has been little attempt to academically examine environmental or green marketing. It introduces the terms and concepts of green marketing, briefly discuss why going green is important and also examine some of the reason that organizations are adopting a green marketing philosophy. It also focuses some of the problems with green marketing

Arthi

2014-03-01

296

ACS Green Chemistry Institute  

Science.gov (United States)

This special feature page from the American Chemical Society (ACS) showcases the up-and-coming field of "green chemistry," that is, the development of chemical products and processes that eliminate or reduce the use and generation of hazardous substances. A list of principles behind green chemistry, a searchable bibliography of green chemistry references, and green chemistry links (including conferences). This page comes from ACS's Green Chemistry Project, a three-year educational project to develop and disseminate green chemistry educational materials for graduate and undergraduate chemistry students.

2005-12-13

297

DEGRADATION KINETICS OF MONOSACCHARIDES IN HYDROCHLORIC, SULFURIC, AND SULFUROUS ACID  

Directory of Open Access Journals (Sweden)

Full Text Available The degradation kinetics of monosaccharides during sulfurous acid treatment was compared to hydrochloric acid and to sulfuric acid treatments. Reaction conditions corresponded to the range found in previous research to allow for the production of hemicelluloses-derived monosaccharides through hydrolysis of wood. Degradation behavior of monosaccharides during treatment with each acid was expressed by a second-order reaction rate constant with respect to substrate and acid concentrations, and the activation energy and frequency factor were calculated using the Arrhenius equation. Results demonstrated that the second-order reaction rate of a monosaccharide was dependent on the type of acid, indicating that monosaccharides degrade at different rates under different acids, even when the molar concentration of the acid is the same. The degradation of monosaccharides in sulfurous acid was much slower than that in hydrochloric acid and in sulfuric acid. A comparison of two sequential treatments with sulfuric acid, with and without the bisulfite ion, showed that sulfurous acid has a protective effect on the degradation of monosaccharides.

Yan Shi,

2012-07-01

298

Metatranscriptomic analysis of sulfur oxidation genes in the endosymbiont of Solemya velum  

Directory of Open Access Journals (Sweden)

Full Text Available Thioautotrophic endosymbionts in the Domain Bacteria mediate key sulfur transformations in marine reducing environments. However, the molecular pathways underlying symbiont metabolism and the extent to which these pathways are expressed in situ are poorly characterized for almost all symbioses. This is largely due to the difficulty of culturing symbionts apart from their hosts. Here, we use pyrosequencing of community RNA transcripts (i.e., the metatranscriptome to characterize enzymes of dissimilatory sulfur metabolism in the model symbiosis between the coastal bivalve Solemya velum and its intracellular thioautotrophic symbionts. High-throughput sequencing of total RNA from the symbiont-containing gill of a single host individual generated 1.6 million sequence reads (500 Mbp. Of these, 43,735 matched Bacteria protein-coding genes in BLASTX searches of the NCBI database. The taxonomic identities of the matched genes indicated relatedness to diverse species of sulfur-oxidizing Gammaproteobacteria, including other thioautotrophic symbionts and the purple sulfur bacterium Allochromatium vinosum. Manual querying of these data identified 28 genes from diverse pathways of sulfur energy metabolism, including the dissimilatory sulfite reductase (Dsr pathway for sulfide oxidation to sulfite, the APS pathway for sulfite oxidation, and the Sox pathway for thiosulfate oxidation. In total, reads matching sulfur energy metabolism genes represented 7% of the Bacteria mRNA pool. Together, these data highlight the dominance of thioautotrophy in the context of symbiont community metabolism, identify the likely pathways mediating sulfur oxidation, and illustrate the utility of metatranscriptome sequencing for characterizing community gene transcription of uncultured symbionts.

FrankStewart

2011-06-01

299

Microbial pathways in colonic sulfur metabolism and links with health and disease  

Directory of Open Access Journals (Sweden)

Full Text Available Sulfur is both crucial to life and a potential threat to health. While colonic sulfur metabolism mediated by eukaryotic cells is relatively well studied, much less is known about sulfur metabolism within gastrointestinal microbes. Sulfated compounds in the colon are either of inorganic (e.g., sulfates, sulfites or organic (e.g., dietary amino acids and host mucins origin. The most extensively studied of the microbes involved in colonic sulfur metabolism are the sulfate-reducing bacteria, which are common colonic inhabitants. Many other microbial pathways are likely to shape colonic sulfur metabolism as well as the composition and availability of sulfated compounds, and these interactions need to be examined in more detail. Hydrogen sulfide is the sulfur derivative that has attracted the most attention in the context of colonic health, and the extent to which it is detrimental or beneficial remains in debate. Several lines of evidence point to sulfate-reducing bacteria or exogenous hydrogen sulfide as potential players in the etiology of intestinal disorders, inflammatory bowel diseases and colorectal cancer in particular. Generation of hydrogen sulfide via pathways other than dissimilatory sulfate reduction may be as, or more, important than those involving the sulfate-reducing bacteria. We suggest here that a novel axis of research is to assess the effects of hydrogen sulfide in shaping colonic microbiome structure. Clearly, in-depth characterization of the microbial pathways involved in colonic sulfur metabolism is necessary for a better understanding of its contribution to colonic disorders and development of therapeutic strategies.

AnnC.Benefiel

2012-11-01

300

X-ray crystallographic analysis of the sulfur carrier protein SoxY from Chlorobium limicola f. thiosulfatophilum reveals a tetrameric structure  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Dissimilatory oxidation of thiosulfate in the green sulfur bacterium Chlorobium limicola f. thiosulfatophilum is carried out by the ubiquitous sulfur-oxidizing (Sox) multi-enzyme system. In this system, SoxY plays a key role, functioning as the sulfur substrate-binding protein that offers its sulfur substrate, which is covalently bound to a conserved C-terminal cysteine, to another oxidizing Sox enzyme. Here, we report the crystal structures of a stand-alone SoxY protein of C. limicola f. thi...

Stout, Jan; Driessche, Gonzalez; Savvides, Savvas N.; Beeumen, Jozef

2007-01-01

 
 
 
 
301

Graphene-sulfur nanocomposites for rechargeable lithium-sulfur battery electrodes  

Energy Technology Data Exchange (ETDEWEB)

Rechargeable lithium-sulfur batteries having a cathode that includes a graphene-sulfur nanocomposite can exhibit improved characteristics. The graphene-sulfur nanocomposite can be characterized by graphene sheets with particles of sulfur adsorbed to the graphene sheets. The sulfur particles have an average diameter less than 50 nm..

Liu, Jun; Lemmon, John P; Yang, Zhenguo; Cao, Yuiliang; Li, Xiaolin

2014-06-17

302

Toxicology of sulfur in ruminants: review  

Energy Technology Data Exchange (ETDEWEB)

This review deals with the toxicology of sulfur in ruminants including toxicity, neurotoxic effects, and mechanism of toxic action of hydrogen sulfide, clinical signs, and treatment. It will report effects of excessive intake of sulfur by ruminants on feed intake, animal performance, ruminal digestion and motility, rumination, and other physiological functions. Poisoning of animals with sulfur from industrial emissions (sulfur dioxide) also is discussed. Excessive quantities of dietary sulfur (above .3 to .4%) as sulfate or elemental sulfur may cause toxic effects and in extreme cases can be fatal. The means is discussed whereby consumption of excessive amounts of sulfur leads to toxic effects. 53 references, 1 table.

Kandylis, K.

1984-10-01

303

Bacteria Inactivation During Lithotripsy  

Science.gov (United States)

The influence of extracorporeal and intracorporeal lithotripsy on the viability of bacteria contained inside artificial kidney stones was investigated in vitro. Two different bacteria were exposed to the action of one extracorporeal shock wave generator and four intracorporeal lithotripters.

Del Sol Quintero, María; Mora, Ulises; Gutiérrez, Jorge; Mues, Enrique; Castaño, Eduardo; Fernández, Francisco; Loske, Achim M.

2006-09-01

304

Sulfur metabolism in Beggiatoa alba.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The metabolism of sulfide, sulfur, and acetate by Beggiatoa alba was investigated under oxic and anoxic conditions. B. alba oxidized acetate to carbon dioxide with the stoichiometric reduction of oxygen to water. In vivo acetate oxidation was suppressed by sulfide and by several classic respiratory inhibitors, including dibromothymoquinone, an inhibitor specific for ubiquinones. B. alba also carried out an oxygen-dependent conversion of sulfide to sulfur, a reaction that was inhibited by seve...

1987-01-01

305

Zirconium in sulfuric acid applications  

International Nuclear Information System (INIS)

Zirconium is one of the few metals that resists attack by sulfuric acid at concentrations up to 75% and temperatures to boiling and above. This capability makes zirconium a good structural metal for use in 40 to 65% H_2SO_4 up to boiling temperatures and for weak acid concentrations at elevated temperatures. Zirconium's corrosion properties in sulfuric acid solutions are compared with nickel base alloys. Examples of applications and limitations in the use of zirconium are presented

1986-01-01

306

For sale: Sulfur emissions  

Energy Technology Data Exchange (ETDEWEB)

The allowance trading market has started a slow march to maturity. Competitive developers should understand the risks and opportunities now presented. The marketplace for sulfur dioxide (SO{sub 2}) emissions allowances - the centerpiece of Title 4's acid rain reduction program - remains enigmatic 19 months after the Clean Air Act amendments of 1990 were passed. Yet it is increasingly clear that the emission allowance market will likely confound the gloom and doom of its doubters. The recently-announced {dollar sign}10 million dollar Wisconsin Power and Light allowance sales to Duquesne Light and the Tennessee Valley Authority are among the latest indications of momentum toward a stabilizing market. This trend puts additional pressure on independent developers to finalize their allowance strategies. Developers who understand what the allowance trading program is and what it is not, know the key players, and grasp the unresolved regulatory issues will have a new competitive advantage. The topics addressed in this article include the allowance marketplace, marketplace characteristics, the regulatory front, forward-looking strategies, and increasing marketplace activity.

Heiderscheit, J. (Chadbourne and Parke, Washington, DC (United States))

307

Leaching of zinc sulfide by Thiobacillus ferrooxidans: Bacterial oxidation of the sulfur product layer increases the rate of zinc sulfide dissolution at high concentrations of ferrous ions  

Energy Technology Data Exchange (ETDEWEB)

This paper reports the results of leaching experiments conducted with and without Thiobacillus ferroxidans at the same conditions in solution. The extent of leaching of ZnS with Bacteria is significantly higher than that without bacteria at high concentrations of ferrous ions. A porous layer of elemental sulfur is present on the surfaces of the chemically leached particles, which no sulfur is present on the surfaces of the bacterially leached particles. The analysis of the data using the shrinking-core model shows that the chemical leaching of ZnS is limited by the diffusion of ferrous ions through the sulfur product layer at high concentrations of ferrous ions. The analysis of the data shows that diffusion through the product layer does not limit the rate of dissolution when bacteria are present. This suggests that the action of T.ferroxidans in oxidizing the sulfur formed on the particle surface is to remove the barrier to diffusion by ferrous ions.

Fowler, T.A.; Crundwell, F.K.

1999-12-01

308

Characterization of iron-sulfur cluster assembly protein IscA from Acidithiobacillus ferrooxidans.  

Science.gov (United States)

IscA is a key member of the iron-sulfur cluster assembly machinery found in bacteria and eukaryotes, but the mechanism of its function in the biogenesis of iron-sulfur cluster remains elusive. In this paper, we demonstrate that Acidithiobacillus ferrooxidans IscA is a [4Fe-4S] cluster binding protein, and it can bind iron in the presence of DTT with an apparent iron association constant of 4·10(20) M(-1). The iron binding in IscA can be promoted by oxygen through oxidizing ferrous iron to ferric iron. Furthermore, we show that the iron bound form of IscA can be converted to iron-sulfur cluster bound form in the presence of IscS and L-cysteine in vitro. Substitution of the invariant cysteine residues Cys35, Cys99, or Cys101 in IscA abolishes the iron binding activity of the protein; the IscA mutants that fail to bind iron are unable to assemble the iron-sulfur clusters. Further studies indicate that the iron-loaded IscA could act as an iron donor for the assembly of iron-sulfur clusters in the scaffold protein IscU in vitro. Taken together, these findings suggest that A. ferrooxidans IscA is not only an iron-sulfur protein, but also an iron binding protein that can act as an iron donor for biogenesis of iron-sulfur clusters. PMID:23586717

Qian, Lin; Zheng, Chunli; Liu, Jianshe

2013-03-01

309

Prevention of the formation of acid drainage from high-sulfur coal, coal refuse, and coal spoils by inhibition of iron and sulfur oxidizing microorganisms. Final report, 1 October 1977-30 June 1981  

Energy Technology Data Exchange (ETDEWEB)

Acid drainage is a problem associated geographically and geologically with the mining industry and is due to production or sulfuric acid from sulfur-containing minerals. The data presented in the report demonstrate that it is possible to inhibit pyrite-oxidizing bacteria in high sulfur coal refuse with a concurrent reduction in acid drainage formed in the refuse. The most effective inhibitors studied are combinations of sodium lauryl sulfate (SLS) plus sodium benzoate (Bz), both of which are relatively nontoxic to higher organisms.

Dugan, P.R.

1985-06-01

310

Identification of a fourth family of lycopene cyclases in photosynthetic bacteria  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A fourth and large family of lycopene cyclases was identified in photosynthetic prokaryotes. The first member of this family, encoded by the cruA gene of the green sulfur bacterium Chlorobium tepidum, was identified in a complementation assay with a lycopene-producing strain of Escherichia coli. Orthologs of cruA are found in all available green sulfur bacterial genomes and in all cyanobacterial genomes that lack genes encoding CrtL- or CrtY-type lycopene cyclases. The cyanobacterium Synechoc...

Maresca, Julia A.; Graham, Joel E.; Wu, Martin; Eisen, Jonathan A.; Bryant, Donald A.

2007-01-01

311

What Is Green?  

Science.gov (United States)

Green is a question with varying answers and sometimes no answer at all. It is a question of location, resources, people, environment, and money. As green really has no end point, a teacher's goal should be to teach students to question and consider green. In this article, the author provides several useful metrics to help technology teachers…

Pokrandt, Rachel

2010-01-01

312

In the Green  

Science.gov (United States)

Education officials used to debate whether they could afford to pursue green design and construction. Now the green movement has gained a foothold not just in education, but in society at large, and the prevailing attitude seems to have shifted. Can schools afford "not" to go green? As budgets are slashed repeatedly, education administrators must…

Kennedy, Mike

2011-01-01

313

Public Libraries Going Green  

Science.gov (United States)

Going green is now a national issue, and patrons expect their library to respond in the same way many corporations have. Libraries are going green with logos on their Web sites, programs for the public, and a host of other initiatives. This is the first book to focus strictly on the library's role in going green, helping you with: (1) Collection…

Miller, Kathryn

2010-01-01

314

Discriminating Bacteria with Optical Sensors Based on Functionalized Nanoporous Xerogels  

Directory of Open Access Journals (Sweden)

Full Text Available An innovative and low-cost method is proposed for the detection and discrimination of indole-positive pathogen bacteria. The method allows the non-invasive detection of gaseous indole, released by bacteria, with nanoporous colorimetric sensors. The innovation comes from the use of nanoporous matrices doped with 4-(dimethylamino-cinnamaldehyde, which act as sponges to trap and concentrate the targeted analyte and turn from transparent to dark green, long before the colonies get visible with naked eyes. With such sensors, it was possible to discriminate E. coli from H. alvei, two indole-positive and negative bacteria after seven hours of incubation.

Sabine Crunaire

2014-06-01

315

Sulfur in agriculture / Enxofre na agricultura  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese A deficiência de enxofre (S) nos solos vem se tornando cada vez mais comum em várias áreas do mundo em razão de práticas agronômicas, alta exportação de biomassa e redução das emissões atmosféricas. Nesta revisão são abordados a incidência, a exploração comercial e estoques de S na natureza, a impor [...] tância do S para as plantas, as formas orgânicas e inorgânicas no solo e suas transformações, assim como, principalmente, o processo de oxidação microbiológica do enxofre elementar (S0) como alternativa para a reposição dos níveis de S do solo. Também é abordada a diversidade de microrganismos oxidantes de S0 nos solos, com destaque para o gênero Thiobacillus, bem como os mecanismos bioquímicos de oxidação do S0 em bactérias. Por fim, foram revisados os principais métodos para determinação da taxa de oxidação do S0 nos solos e as variáveis que influenciam esse processo. Abstract in english Sulfur (S) deficiency in soils is becoming increasingly common in many areas of the world as a result of agronomic practices, high biomass exportation and reduced S emissions to the atmosphere. In this review, the incidence and commercial exploitation of S pools in nature are discussed, as well as t [...] he importance of S for plants and the organic and inorganic S forms in soil and their transformations, especially the process of microbiological oxidation of elemental sulfur (S0) as an alternative to the replenishment of S levels in the soil. The diversity of S0-oxidizing microorganisms in soils, in particular the genus Thiobacillus, and the biochemical mechanisms of S0 oxidation in bacteria were also addressed. Finally, the main methods to measure the S0 oxidation rate in soils and the variables that influence this process were revised.

Adriano Reis, Lucheta; Marcio Rodrigues, Lambais.

316

Sulfur in agriculture Enxofre na agricultura  

Directory of Open Access Journals (Sweden)

Full Text Available Sulfur (S deficiency in soils is becoming increasingly common in many areas of the world as a result of agronomic practices, high biomass exportation and reduced S emissions to the atmosphere. In this review, the incidence and commercial exploitation of S pools in nature are discussed, as well as the importance of S for plants and the organic and inorganic S forms in soil and their transformations, especially the process of microbiological oxidation of elemental sulfur (S0 as an alternative to the replenishment of S levels in the soil. The diversity of S0-oxidizing microorganisms in soils, in particular the genus Thiobacillus, and the biochemical mechanisms of S0 oxidation in bacteria were also addressed. Finally, the main methods to measure the S0 oxidation rate in soils and the variables that influence this process were revised.A deficiência de enxofre (S nos solos vem se tornando cada vez mais comum em várias áreas do mundo em razão de práticas agronômicas, alta exportação de biomassa e redução das emissões atmosféricas. Nesta revisão são abordados a incidência, a exploração comercial e estoques de S na natureza, a importância do S para as plantas, as formas orgânicas e inorgânicas no solo e suas transformações, assim como, principalmente, o processo de oxidação microbiológica do enxofre elementar (S0 como alternativa para a reposição dos níveis de S do solo. Também é abordada a diversidade de microrganismos oxidantes de S0 nos solos, com destaque para o gênero Thiobacillus, bem como os mecanismos bioquímicos de oxidação do S0 em bactérias. Por fim, foram revisados os principais métodos para determinação da taxa de oxidação do S0 nos solos e as variáveis que influenciam esse processo.

Adriano Reis Lucheta

2012-11-01

317

Green Venezuela - Climate &  

...Green Venezuela - Climate & Capitalism Climate & Capitalism An ecosocialist journal Home About Ecosocialist Notebook Book Reviews Archives Articles By Subject ...Review MR Press MRzine Economist’s Travelogue You are here: Home / 2007 / April / 09 / Green Venezuela Posted on April 9, 2007 Green Venezuela The Principal Speaker ...party, the Green Party of England and Wales, is affiliated to the Venezuela Information Centre (VIC), which is a solidarity organisation ...on the whole the Green Party is pretty supportive of solidarity with Venezuela. To my mind, the Bolivarian process is important for ...

318

GREEN MARKETING : GREEN ENVIRONMENT - STRATEGIES AND CHALLENGES  

Directory of Open Access Journals (Sweden)

Full Text Available -Green marketing is a phenomenon which has developed particular import in the modern market. This concept has enabled for the re-marketing and packing of existing products which already adhere to such guidelines. Additionally, the development of green marketing has opened the door of opportunity for companies to co-brand their products into separate line, lauding the green-friendliness of some while ignoring that of others. Such marketing techniques as will be explained are as a direct result of movement in the minds of the consumer market

Bhurelal Patidar

2014-05-01

319

Significance of Size and Nucleic Acid Content Heterogeneity as Measured by Flow Cytometry in Natural Planktonic Bacteria  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Total bacterial abundances estimated with different epifluorescence microscopy methods (4?,6-diamidino-2-phenylindole [DAPI], SYBR Green, and Live/Dead) and with flow cytometry (Syto13) showed good correspondence throughout two microcosm experiments with coastal Mediterranean water. In the Syto13-stained samples we could differentiate bacteria with apparent high DNA (HDNA) content and bacteria with apparent low DNA (LDNA) content. HDNA bacteria, “live” bacteria (determined as such with ...

Gasol, Josep M.; Zweifel, Ulla Li; Peters, Francesc; Fuhrman, Jed A.; Hagstro?m, A?ke

1999-01-01

320

Green metrics evaluation of isoprene production by microalgae and bacteria  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Isoprene is a key intermediate compound for the production of synthetic rubber and adhesives and is also used as a building block in the chemical industry. Traditionally, isoprene is obtained from crude oil during the refinery process. Nevertheless, plants and animals are also able to synthesize this important compound. This work compares two renewable approaches for isoprene production: by photosynthetic organisms (autotrophic microalgae/cyanobacteria) and by heterotrophic organisms (bacteri...

Matos, Cristina T.; Gouveia, L.; Morais, Ana Rita; Reis, Alberto; Bogel-lukasik, R.

2013-01-01

 
 
 
 
321

Sulfur as a lunar resource  

Science.gov (United States)

Results of a study of seven lava samples from the Apollo 17 landing site are presented. The samples are polished thin sections. Backscattered electron images on an SEM were used to process gray-level spectra to separate the triolite crystals; these were verified with the X-ray spectra. It is found that the quantities of sulfur to be gained by thermal processing are strongly influenced by duration of heating and sample processing; effective processing may require heating with active thermochemical reaction to extract the sulfur as H2S or SO2. The speciation of the sulfur gases evolved might be controlled by manipulation of temperature, total pressure, and partial gas pressures of the extraction environment.

Heiken, G.; Vaniman, D.; Hawkins, H.

322

Monodisperse sulfuric acid aerosol generator  

Energy Technology Data Exchange (ETDEWEB)

A simple sulfuric acid aerosol generator which provides a reproducible aerosol of narrow size distribution has been developed. The method is based on the injection of heated SO/sub 3/ vapor in N/sub 2/ into a stream of humidified air. Particle diameter is adjustable from approximately 0.3 to 1.5 ..mu..m with a relative standard deviation of between 0.12 and 0.20. The generator is also capable of producing particles of <0.3 ..mu..m and >1.5 ..mu..m under special conditions. The sulfuric acid aerosol size distribution was obtained from optical particle counter data and verified using electron microscopy. The sulfuric acid concentration range of the generator is 0.3-3 mgm/sup -3/ depending upon the particle size produced.

Wall, S.

1982-01-01

323

Sensory quality of turnip greens and turnip tops grown in northwestern Spain  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In Galicia (northwestern Spain), Brassica rapa var. rapa L. includes turnip greens and turnip tops as vegetable products. They are characterized by a particular sulfurous aroma, pungent flavor, and a bitter taste. In this work twelve local varieties grown as turnip greens and turnip tops were evaluated to define the sensory attributes, to relate them with secondary metabolites, and to select those sensorial traits that better describe these crops. Results showed differences in the sensory pro...

Francisco Candeira, Marta; Velasco Pazos, Pablo; Romero, A?ngeles; Va?zquez, Lourdes; Cartea Gonza?lez, Mari?a Elena

2009-01-01

324

Heat recovery from concentrated sulfuric acid  

Energy Technology Data Exchange (ETDEWEB)

This patent describes improvement in a process for the manufacture of sulfuric acid. It comprises: the catalytic oxidation of sulfur dioxide to sulfur trioxide, absorption of the sulfur trioxide in sulfuric acid, and cooling the sulfuric acid in a heat exchanger by transfer of heat to another fluid. The improvement comprises contacting a gas comprising sulfur trioxide with sulfuric acid in a primary absorption zone in a heat recovery tower, the sulfuric acid having a concentration between 98% and 101% and a temperature of at least 120{degrees} C.; contacting the gas exiting from the primary absorption zone with sulfuric acid in a secondary absorption zone positioned above the primary absorption zone in the heat recovery tower, the inlet temperature of the sulfuric acid to the secondary absorption zone being at least 10{degrees} C. cooler than the inlet temperature of the sulfuric acid to the primary absorption zone; and removing the heat of absorption in useful form from the sulfuric acid exiting the primary absorption zone by transfer of heat to another fluid, and thereby heating the another fluid to a temperature greater than 120{degrees} C.

McAlister, D.R.; Ziebold, S.A.

1991-02-26

325

Heavy metal removal from contaminated sludges with dissolved sulfur dioxide in combination with bacterial leaching  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Treatment of dredged sludge from the Hamburg harbour area with sulfurous acid (6%) shows nearly complete removal of Cd, Zn, and Mn within the first 10 minutes. Within 1 hour more than 50% of Cr, Ni, Pb and Hg are mobilized; dissolution of Cu and Fe reaches about 40%. The capability of certain bacteria (Thiobacillus thiooxidans and Thiobacillus ferrooxidans) to oxidize sulfur and ferrous iron respectively, while decreasing the pH value from 4-5 to about 2 was utilized for enhancing dissolution...

Calmano, Wolfgang; Ahlf, Wolfgang; Fo?rstner, Ulrich

1983-01-01

326

A cryptic sulfur cycle driven by iron below the sulfate-methane transition zone  

Digital Repository Infrastructure Vision for European Research (DRIVER)

My Ph.D thesis deals with biogeochemical cycling of carbon, sulfur and iron compounds in marine sediments on the continental shelves in relation to the activity and distribution of sulfate-reducing bacteria below the sulfate-methane transition. The aim of the first report was to study sulfate reduction and sulfur-iron geochemistry in deep gravity cores of Holocene mud collected from Bay of Aarhus (Denmark). It was the goal to understand if sulfate is generated by reoxidation of sulfide throug...

Holmkvist, Lars

2009-01-01

327

Crystal structure of the electron carrier domain of the reaction center cytochrome c(z) subunit from green photosynthetic bacterium Chlorobium tepidum.  

Science.gov (United States)

In green sulfur photosynthetic bacteria, the cytochrome c(z) (cyt c(z)) subunit in the reaction center complex mediates electron transfer mainly from menaquinol/cytochrome c oxidoreductase to the special pair (P840) of the reaction center. The cyt c(z) subunit consists of an N-terminal transmembrane domain and a C-terminal soluble domain that binds a single heme group. The periplasmic soluble domain has been proposed to be highly mobile and to fluctuate between oxidoreductase and P840 during photosynthetic electron transfer. We have determined the crystal structure of the oxidized form of the C-terminal functional domain of the cyt c(z) subunit (C-cyt c(z)) from thermophilic green sulfur bacterium Chlorobium tepidum at 1.3-A resolution. The overall fold of C-cyt c(z) consists of four alpha-helices and is similar to that of class I cytochrome c proteins despite the low similarity in their amino acid sequences. The N-terminal structure of C-cyt c(z) supports the swinging mechanism previously proposed in relation with electron transfer, and the surface properties provide useful information on possible interaction sites with its electron transfer partners. Several characteristic features are observed for the heme environment: These include orientation of the axial ligands with respect to the heme plane, surface-exposed area of the heme, positions of water molecules, and hydrogen-bond network involving heme propionate groups. These structural features are essential for elucidating the mechanism for regulating the redox state of cyt c(z). PMID:20156447

Hirano, Yu; Higuchi, Makoto; Azai, Chihiro; Oh-Oka, Hirozo; Miki, Kunio; Wang, Zheng-Yu

2010-04-16

328

Interspecies communication in bacteria  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Until recently, bacteria were considered to live rather asocial, reclusive lives. New research shows that, in fact, bacteria have elaborate chemical signaling systems that enable them to communicate within and between species. One signal, termed AI-2, appears to be universal and facilitates interspecies communication. Many processes, including virulence factor production, biofilm formation, and motility, are controlled by AI-2. Strategies that interfere with communication in bacteria are bein...

Federle, Michael J.; Bassler, Bonnie L.

2003-01-01

329

Bacteria-Antagonists  

International Science & Technology Center (ISTC)

Development of Biological Control Agents Through Use of Recombinant Antagonistic Bacteria Possessing Variable Mechanisms of Antagonisms, High Colonizing Capacity and Marker Traits for their Monitoring in Nature

330

Silica Sulfuric Acid Promotes Aza-Michael Addition Reactions under Solvent-Free Condition as a Heterogeneous and Reusable Catalyst  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A highly efficient, inexpensive, recyclable, convenient, and green protocol for chemoselective aza-Michael addition reactions of amines/thiols to ?,?-unsaturated compounds using silica sulfuric acid (SSA or SiO2-SO3H) was developed. This method is simple, convenient and the title compounds are produced in good to excellent yields.

2009-01-01

331

Durability of incinerator ash waste encapsulated in modified sulfur cement  

International Nuclear Information System (INIS)

Waste form stability under anticipated disposal conditions is an important consideration for ensuring continued isolation of contaminants from the accessible environment. Modified sulfur cement is a relatively new material and has only recently been applied as a binder for encapsulation of mixed wastes. Little data are available concerning its long-term durability. Therefore, a series of property evaluation tests for both binder and waste-binder combinations have been conducted to examine potential waste form performance under storage and disposal conditions. These tests include compressive strength, biodegradation, radiation stability, water immersion, thermal cycling, and leaching. Waste form compressive strength increased with ash waste loadings to 30.5 MPa at a maximum incinerator ash loading of 43 wt %. Biodegradation testing resulted in no visible microbial growth of either bacteria or fungi. Initial radiation stability testing did not reveal statistically significant deterioration in structural integrity. Results of 90 day water immersion tests were dependent on the type of ash tested. There were no statistically significant changes in compressive strength detected after completion of thermal cycle testing. Radionuclides from ash waste encapsulated in modified sulfur cement leached between 5 and 8 orders of magnitude slower than the leach index criterion established by the Nuclear Regulatory Commission (NRC) for low-level radioactive waste. Modified sulfur cement waste forms containing up to 43 wt % incinerator fly ash passed EPA Toxicity Characteristic Leaching Procedure (TCLP) criteria for lead and cadmium leachability. 11 refs., 2 figs., 5 tabs

1991-05-13

332

Sulfur Chemistry in Bacterial Leaching of Pyrite  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the case of pyrite bioleaching by Leptospirillum ferrooxidans, an organism without sulfur-oxidizing capacity, besides the production of tetra- and pentathionate, a considerable accumulation of elemental sulfur occurred. A similar result was obtained for chemical oxidation assays with acidic, sterile iron(III) ion-containing solutions. In the case of Thiobacillus ferrooxidans, only slight amounts of elemental sulfur were detectable because of the organism's capacity to oxidize sulfur compou...

Schippers, A.; Jozsa, P.; Sand, W.

1996-01-01

333

Immunobiological Consequences of Sulfur Mustard Contamination  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Sulfur mustard has been employed in chemical warfare in certain regions including Iran. The short and long term biological effects of sulfur mustard contamination have been studied in both basic and clinical aspects. Sulfur mustard has been shown to induce a vast array of pathological effects in affected persons. In addition to skin, lung, eyes and gastrointestinal disturbances, sulfur mustard has been shown to induce hematological complications and a severe suppression of the immune system. ...

2006-01-01

334

Anaerobic microbial degradation of methylated sulfur compounds  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Dimethylsulfide (DMS) is one of the most abundant organic sulfur compounds in the marine environment and is thought to play an important role in the formation of cloud condensation nuclei through its atmospheric oxidation products methanesulfonic acid and sulfuric acid. DMS also forms a crucial link in the global sulfur cycle because it is the main sulfur species that is transported from marine to terrestrial environments. The precursor of DMS in marine environments is the osmolyte dimethylsu...

Maarel, Marc Jos Elise Cornelis

1996-01-01

335

Antibotulinal efficacy of sulfur dioxide in meat.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The addition of sodium metabisulfite as a source of sulfur dioxide delayed botulinal outgrowth in perishable canned comminuted pork when it was temperature abused at 27 degree C. The degree of inhibition was directly related to the level of sulfur dioxide. Levels greater than 100 microgram of sulfur dioxide per g were necessary to achieve significant inhibition when a target level of 100 botulinal spores per g was used. Sodium nitrite partially reduced the efficacy of the sulfur dioxide. Sulf...

1980-01-01

336

Equity, Efficiency and Sulfur Emission Reductions  

Energy Technology Data Exchange (ETDEWEB)

This paper evaluates possible sulfur emission policy options from the perspective of equity and efficiency. Efficiency has two relevant aspects relating to emission reductions: allocative and productive. Allocative efficiency to the determination of the optimal level of sulfur emissions. Productive efficiency requires the reduction of sulfur at the lowest possible cost. Once the optimal level of sulfur emissions has been established, the question must be addressed of how to achieve any needed reductions, and who will pay for them.

Peachman, C.

1984-01-01

337

Green gadgets for dummies  

CERN Document Server

Save some green by going green with these environmentally friendly gadgets! With concern for the future of our environment growing stronger and more serious every day, there has never been a better time to take a new approach to some of the most popular gizmos and gadgets on the market and learn how you can convernt to electronics that have minimal environmental impact. Green gadgets encompass everything from iPods to energy-efficient home entertainment devices to solar laptop chargers and crank-powered gizmos. This helpful resource explains how to research green gadgets, make a smart purc

Hutsko, Joe

2009-01-01

338

Investigation of energy gene expressions and community structures of free and attached acidophilic bacteria in chalcopyrite bioleaching.  

Science.gov (United States)

In order to better understand the bioleaching mechanism, expression of genes involved in energy conservation and community structure of free and attached acidophilic bacteria in chalcopyrite bioleaching were investigated. Using quantitative real-time PCR, we studied the expression of genes involved in energy conservation in free and attached Acidithiobacillus ferrooxidans during bioleaching of chalcopyrite. Sulfur oxidation genes of attached A. ferrooxidans were up-regulated while ferrous iron oxidation genes were down-regulated compared with free A. ferrooxidans in the solution. The up-regulation may be induced by elemental sulfur on the mineral surface. This conclusion was supported by the results of HPLC analysis. Sulfur-oxidizing Acidithiobacillus thiooxidans and ferrous-oxidizing Leptospirillum ferrooxidans were the members of the mixed culture in chalcopyrite bioleaching. Study of the community structure of free and attached bacteria showed that A. thiooxidans dominated the attached bacteria while L. ferrooxidans dominated the free bacteria. With respect to available energy sources during bioleaching of chalcopyrite, sulfur-oxidizers tend to be on the mineral surfaces whereas ferrous iron-oxidizers tend to be suspended in the aqueous phase. Taken together, these results indicate that the main role of attached acidophilic bacteria was to oxidize elemental sulfur and dissolution of chalcopyrite involved chiefly an indirect bioleaching mechanism. PMID:22968225

Zhu, Jianyu; Jiao, Weifeng; Li, Qian; Liu, Xueduan; Qin, Wenqing; Qiu, Guanzhou; Hu, Yuehua; Chai, Liyuan

2012-12-01

339

Sulfur diffusion in titanium and its alloys  

International Nuclear Information System (INIS)

Sulfur diffusion in titanium at 885-950 deg C and alloy VT6C (Ti-4.5% Al-3.5% V) in the temperature range of ?-phase existence is investigated. Using autoradiography method the distribution of sulfur over diffusion zone depth is obtained. The conclusion is made that sulfur diffusion in titanium is realized by interstitial mechanism

1986-01-01

340

Sulfur monochloride in organic synthesis  

Science.gov (United States)

The data on the reactivity of sulfur monochloride published in the past 15 years have been reviewed and systematized. The review focuses on the synthesis of acyclic and heterocyclic compounds with the use of S2Cl2. The bibliography includes 154 references.

Konstantinova, L. S.; Rakitin, O. A.

2014-03-01

 
 
 
 
341

Radiation induced sulfur dioxide removal  

International Nuclear Information System (INIS)

The biggest source of air pollution is the combustion of fossil fuels, were pollutants such as particulate, sulfur dioxide (SO2), nitrogen oxides (NOx), and volatile organic compounds (VOC) are emitted. Among these pollutants, sulfur dioxide plays the main role in acidification of the environment. The mechanism of sulfur dioxide transformation in the environment is partly photochemical. This is not direct photooxidation, however, but oxidation through formed radicals. Heterogenic reactions play an important role in this transformation as well; therefore, observations from environmental chemistry can be used in air pollution control engineering. One of the most promising technologies for desulfurization of the flue gases (and simultaneous denitrification) is radiation technology with an electron accelerator application. Contrary to the nitrogen oxides (NOx) removal processes, which is based on pure radiation induced reactions, sulfur dioxide removal depends on two pathways: a thermochemical reaction in the presence of ammonia/water vapor and a radiation set of radiochemical reactions. The mechanism of these reactions and the consequent technological parameters of the process are discussed in this paper. The industrial application of this radiation technology is being implemented in an industrial pilot plant operated by INCT at EPS Kaweczyn. A full-scale industrial plant is currently in operation in China, and two others are under development in Japan and Poland. (author)

1998-08-23

342

Synthesis and antibacterial activity of novel oxazolidinones with methylene oxygen- and methylene sulfur-linked substituents at C5-position.  

Science.gov (United States)

Novel oxazolidinone derivatives of the lead compound RBx 8700, containing methylene oxygen- and methylene sulfur-linked substituents at the C5-position, were synthesized. Antibacterial screening of these compounds against a panel of resistant and susceptible Gram-positive and fastidious Gram-negative bacteria gave compounds 2 and 4 as new antibacterial agents. PMID:17618116

Rudra, Sonali; Sangita, Fnu; Gujrati, Arti; Pandya, Manisha; Bhateja, Pragya; Mathur, Tarun; Singhal, Smita; Rattan, Ashok; Salman, Mohammed; Das, Biswajit

2007-09-01

343

Sustainable green urban planning: the Green Credit Tool  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Purpose – The Green Credit Tool is evaluated as a method to quantify the value of green-spaces and to determine how these green-space-values can be replaced or compensated for within urban spatial planning projects. Design/methodology/approach – Amersfoort Local Municipality created the Green Credit Tool to ensure protection and enhancement of the urban green totality. The tool is described and evaluated based on three core elements: the value matrix, the collection of values and green co...

2010-01-01

344

Green Management and Green Technology – Exploring the Causal Relationship  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, we analyze potential endogeneity problems in former econometric studies which regress corporate environmental performance such as green technology activities on green management. Based on evolutionary theory and the resource-based view of the firm, we discuss in the first step that green technology could also influence green management and that unobserved firm characteristics could simultaneously influence green management and green technology. Contrary to existing studies, we ...

2006-01-01

345

Green management and green technology - exploring the causal relationship  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, we analyze potential endogeneity problems in former econometric studies which regress corporate environmental performance such as green technology activities on green management. Based on evolutionary theory and the resource-based view of the firm, we discuss in the first step that green technology could also influence green management and that unobserved firm characteristics could simultaneously influence green management and green technology. Contrary to existing studies, we ...

Nogareda, Jazmin Seijas; Ziegler, Andreas

2006-01-01

346

Nitrogen and Sulfur Requirements for Clostridium thermocellum and Caldicellulosiruptor bescii on Cellulosic Substrates in Minimal Nutrient Media  

Energy Technology Data Exchange (ETDEWEB)

Growth media for cellulolytic Clostridium thermocellum and Caldicellulosiruptor bescii bacteria usually contain excess nutrients that would increase costs for consolidated bioprocessing for biofuel production and create a waste stream with nitrogen, sulfur and phosphate. C. thermocellum was grown on crystalline cellulose with varying concentrations of nitrogen and sulfur compounds, and growth rate and alcohol production response curves were determined. Both bacteria assimilated sulfate in the presence of ascorbate reductant, increasing the ratio of oxidized to reduced fermentation products. From these results, a low ionic strength, defined minimal nutrient medium with decreased nitrogen, sulfur, phosphate and vitamin supplements was developed for the fermentation of cellobiose, cellulose and acid-pretreated Populus. Carbon and electron balance calculations indicate the unidentified residual fermentation products must include highly reduced molecules. Both bacterial populations were maintained in co-cultures with substrates containing xylan or hemicellulose in defined medium with sulfate and basal vitamin supplements.

Kridelbaugh, Donna M [ORNL; Nelson, Josh C [ORNL; Engle, Nancy L [ORNL; Tschaplinski, Timothy J [ORNL; Graham, David E [ORNL

2013-01-01

347

The Green Office  

CERN Document Server

Any Green IT strategy should include a Green Office component, that tackles power consumption and paper usage in the office/work environment as well as in the data centre. While the most significant savings are made where the bulk of data processing is carried out (ie the data centre), savings can also be achieved in terms of workstations and related office IT equipment.

Calder, Alan

2009-01-01

348

A Green Clean  

Science.gov (United States)

In the professional cleaning industry, green cleaning has been much discussed in the past few years. Usually, the information pertains to the many reasons why a green cleaning program should be started, the steps involved to get the program off the ground, and the potential benefits. However, although many facility managers and school…

Kravitz, Robert

2006-01-01

349

AMAX for Harraby Green  

AMAX for Harraby Green Back to station AMAX Data for: Petteril at Harraby Green (76010) QMED = 31.5m 3/s Note: Place the mouse cursor over a column heading to view a description of the data in that column Rank Water Year Date Time Stage Flow Rating Source Ref Available Data Comments 24 1970-71 15/08…

350

Green technology in Taiwan  

International Nuclear Information System (INIS)

Taiwan is striving for leadership in the field of green Technologies. Solar cells and Light Emitting Diodes (LED) are the best examples of successful Taiwanese green technologies. Electronic vehicles and smart grids are giving new impetus to the Taiwanese export of high-quality technology.

2010-06-01

351

Green Cleaning Label Power  

Science.gov (United States)

Green cleaning plays a significant and supportive role in helping education institutions meet their sustainability goals. However, identifying cleaning products, supplies and equipment that truly are environmentally preferable can be daunting. The marketplace is inundated with products and services purporting to be "green" or environmentally…

Balek, Bill

2012-01-01

352

The Green Party  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This chapter is focused on the Czech Green Party. It presents its turbulent existence since the Velvet Revolution, his recent electoral and governmental emergence. The paper discusses the difficulties in implementing a green program in the Czech governmental context. It concludes on an analysis of the limited institutionalization of the party in practice and its dependence from political personalities.

Perottino, Michel

2009-01-01

353

Green by Default  

DEFF Research Database (Denmark)

The article offers information on the two sources of energy including green energy and gray energy. It discusses several facts which includes lower levels of greenhouse gases and conventional pollutants, relationship between economic incentives and underlying preferences and potential effects of green default rules..

Sunstein, Cass R.; Reisch, Lucia

2013-01-01

354

Green Chemistry and Education.  

Science.gov (United States)

Many students today are profoundly interested in the sustainability of their world. Introduces Green Chemistry and its principles with teaching materials. Green Chemistry is the use of chemistry for pollution prevention and the design of chemical products and processes that are environmentally benign. (ASK)

Hjeresen, Dennis L.; Schutt, David L.; Boese, Janet M.

2000-01-01

355

Sulfur bonding in fluidized-bed combustion  

Energy Technology Data Exchange (ETDEWEB)

Limestone use in desulfurization of flue gas during fluidized-bed combustion of coal is discussed. Reactions of sulfur dioxide with calcium oxide, sulfur dioxide with oxygen, and sulfur trioxide with calcium oxide are analyzed. Equations which describe desulfurization and effects of selected factors on desulfurization are derived. Desulfurization efficiency increases with increasing molar relation of calcium oxide to sulfur and with increasing initial sulfur concentration in flue gas. Accuracy of these general dependences is analyzed on the example of three coal types from Hungary (from Banhida, Tatabanya and Ajka) used in fluidized-bed combustion. Analysis results are shown in three diagrams. 4 references.

Boross, L.

1985-04-01

356

Green Map Atlas  

Science.gov (United States)

Based in New York, the people behind the Green Atlas have been going "green" since 1995. The Green Map system is an "adaptable framework for charting nature and culture in hometown environments." Recently, they published the Green Map Atlas, and now visitors can access the entire publication on this site. The Atlas includes maps of Jakarta, Kyoto, New York, Milwaukee, Toronto, and six other areas around the world. Visitors will find all types of interesting information on each of these maps, including the locations of community gardens, green spaces, bike trails, and other environmentally-friendly aspects of the built environment. It's certainly a novel and new way to think about communities, and these maps could also be used in courses on environmental science or urban planning.

357

"Green Schools" in China  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper you can see the history and the connotation of "Green Schools". Through an analysis of a case, the paper indicate that it has been formed some essential characters of "Green Schools" in China.In recent years the development of Chinese "Green Schools" was speedy, and gained some achievement. The paper recommend this, too.There are some problems and obstacles in the development. We must think much of this, and resolve it. There are some contrasts between some foreign countries and China about the characters of "Green Schools". There are some discussions and solved measures about the problems and obstacles of "Green Schools" in the 4th part.

Fang XIAO

2002-12-01

358

Biharmonic Green functions  

Directory of Open Access Journals (Sweden)

Full Text Available The harmonic Green and Neumann function and a particular Robin function are used to construct bi-harmonic Green, Neumann and particular Robin functions. Moreover hybrid bi-harmonic Green functions are given. They all are constructed via a convolution of the mentioned harmonic particular fundamental solutions. In case of the unit disc they are explicitly expressed. Besides these 9 bi-harmonic Green functions there is another bi-harmonic Green function in explicit form for the unit disc not defined by convolution. Related boundary value problems are not all well posed. In case they are, the unique solutions are given. For the other cases solvability conditions are determined and the unique solutions found. There are all together 12 Dirichlet kind boundary value problems for the inhomogeneous bi-harmonic equation treated. The investigation is restricted to the two dimensional case and complex notation is used.

Heinrich Begehr

2006-11-01

359

Microphysical simulations of sulfur burdens from stratospheric sulfur geoengineering  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Recent microphysical studies suggest that geoengineering by continuous stratospheric injection of SO2 gas may be limited by the growth of the aerosols. We study the efficacy of SO2, H2SO4 and aerosol injections on aerosol mass and optical depth using a three-dimensional general circulation model with sulfur chemistry and sectional aerosol microphysics (WACCM/CARMA). We find increasing injection rates o...

English, J. M.; Toon, O. B.; Mills, M. J.

2012-01-01

360

Collection Development "Green Business": The Green Capitalist  

Science.gov (United States)

The "greening" of corporate behemoths like Wal-Mart, DuPont, and Toyota has received much media attention in recent years. But consider small businesses: according to the U.S. Small Business Administration, of the estimated 27 million firms in the United States, 99.7 percent have fewer than 500 employees, 97.5 percent have fewer than 20, and more…

Eagan, Robert

2009-01-01

 
 
 
 
361

Phylogenetic analysis on the soil bacteria distributed in karst forest  

Directory of Open Access Journals (Sweden)

Full Text Available Phylogenetic composition of bacterial community in soil of a karst forest was analyzed by culture-independent molecular approach. The bacterial 16S rRNA gene was amplified directly from soil DNA and cloned to generate a library. After screening the clone library by RFLP, 16S rRNA genes of representative clones were sequenced and the bacterial community was analyzed phylogenetically. The 16S rRNA gene inserts of 190 clones randomly selected were analyzed by RFLP and generated 126 different RFLP types. After sequencing, 126 non-chimeric sequences were obtained, generating 113 phylotypes. Phylogenetic analysis revealed that the bacteria distributed in soil of the karst forest included the members assigning into Proteobacteria, Acidobacteria, Planctomycetes, Chloroflexi (Green nonsulfur bacteria, Bacteroidetes, Verrucomicrobia, Nitrospirae, Actinobacteria (High G+C Gram-positive bacteria, Firmicutes (Low G+C Gram-positive bacteria and candidate divisions (including the SPAM and GN08.

JunPei Zhou

2009-12-01

362

Facile synthesis, spectral properties and formation mechanism of sulfur nanorods in PEG-200  

Energy Technology Data Exchange (ETDEWEB)

Graphical abstract: Homogeneous rod-like structure of sulfur with a typical diameter of about 80 nm and an average aspect ratio of about 6–8 was obtained. The sulfur nanoparticles could self-assemble from spherical particles to nanorods in PEG-200. During the self-assembling process, the absorption band showed a red shift which was due to the production of nanorods. Highlights: ? A novel, facile and greener method to synthesize sulfur nanorods by the solubilizing and templating effect of PEG-200 was reported. ? S{sup 0} nanoparticles could self assemble in PEG-200 and finally form monodisperse and homogeneous rod-like structure with an average diameter of about 80 nm, the length ca. 600 nm. ? The absorption band showed a red shift and the RRS intensity enhanced continuously during the self-assembling process. ? PEG-200 induced the oriented attachment of sulfur nanoparticles by the terminal hydroxyl groups. -- Abstract: The synthesis of nano-sulfur sol by dissolving sublimed sulfur in a green solvent-PEG-200 was studied. Homogeneous rod-like structure of sulfur with a typical diameter of about 80 nm and an average aspect ratio of 6–8 was obtained. The structure, morphology, size, and stability of the products were investigated by transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and dynamic light scattering (DLS) measurements. The spectral properties of the products were investigated by ultraviolet-visible (UV–vis) absorption and resonance Rayleigh scattering spectroscopy (RRS). The results showed that the spherical sulfur nanoparticles could self-assemble into nanorods in PEG-200. During the self-assembling process, the absorption band showed a red shift and the RRS intensity enhanced continuously. There was physical cross-linking between PEG and sulfur nanoparticles. PEG-200 induced the oriented attachment of sulfur nanoparticles by the terminal hydroxyl groups. This research provides a greener and more environment-friendly synthetic method for the production of sulfur nanorods.

Xie, Xin-yuan; Li, Li-yun; Zheng, Pu-sheng [Department of Chemistry, Jinan University, Guangzhou 510632 (China); Zheng, Wen-jie, E-mail: tzhwj@jnu.edu.cn [Department of Chemistry, Jinan University, Guangzhou 510632 (China); Bai, Yan; Cheng, Tian-feng; Liu, Jie [Department of Chemistry, Jinan University, Guangzhou 510632 (China)

2012-11-15

363

Facile synthesis, spectral properties and formation mechanism of sulfur nanorods in PEG-200  

International Nuclear Information System (INIS)

Graphical abstract: Homogeneous rod-like structure of sulfur with a typical diameter of about 80 nm and an average aspect ratio of about 6–8 was obtained. The sulfur nanoparticles could self-assemble from spherical particles to nanorods in PEG-200. During the self-assembling process, the absorption band showed a red shift which was due to the production of nanorods. Highlights: ? A novel, facile and greener method to synthesize sulfur nanorods by the solubilizing and templating effect of PEG-200 was reported. ? S0 nanoparticles could self assemble in PEG-200 and finally form monodisperse and homogeneous rod-like structure with an average diameter of about 80 nm, the length ca. 600 nm. ? The absorption band showed a red shift and the RRS intensity enhanced continuously during the self-assembling process. ? PEG-200 induced the oriented attachment of sulfur nanoparticles by the terminal hydroxyl groups. -- Abstract: The synthesis of nano-sulfur sol by dissolving sublimed sulfur in a green solvent-PEG-200 was studied. Homogeneous rod-like structure of sulfur with a typical diameter of about 80 nm and an average aspect ratio of 6–8 was obtained. The structure, morphology, size, and stability of the products were investigated by transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and dynamic light scattering (DLS) measurements. The spectral properties of the products were investigated by ultraviolet-visible (UV–vis) absorption and resonance Rayleigh scattering spectroscopy (RRS). The results showed that the spherical sulfur nanoparticles could self-assemble into nanorods in PEG-200. During the self-assembling process, the absorption band showed a red shift and the RRS intensity enhanced continuously. There was physical cross-linking between PEG and sulfur nanoparticles. PEG-200 induced the oriented attachment of sulfur nanoparticles by the terminal hydroxyl groups. This research provides a greener and more environment-friendly synthetic method for the production of sulfur nanorods.

2012-11-01

364

The microbial sulfur cycle at extremely haloalkaline conditions of soda lakes  

Directory of Open Access Journals (Sweden)

Full Text Available Microbial sulfur cycle is among the most active in soda lakes. Oxidative part of the cycle is driven by chemolithoautotrophic haloalkaliphilic sulfur-oxidizing bacteria. They are present at high number of up to 106 viable cells/cm3 and represented by four genera within the Gammaproteobacteria, Thioalkalivibrio, Thioalkalimicrobium, Thioalkalispira and Thioalkalibacter. The genus Thioalkalivibrio is the most physiologically diverse and covers whole spectrum of salt/pH conditions present in soda lakes. The dominant subgroup of this genus is able to grow in saturated soda brines containing 4 M total Na+ - a unique property for any known aerobic chemolithoautotrophs. Some of the species can use thiocyanate as a sole energy source and 3 species out of 9 can grow anaerobically with nitrogen oxides. The reductive part of the cycle is also active in anoxic sediments of various soda lakes. In situ and laboratory experiments showed high sulfate reduction rates only hampered at salt-saturated conditions. The highest rates of sulfidogenesis were observed with elemental sulfur followed by thiosulfate. Formate was the most efficient electron donor with all three sulfur electron acceptors, while acetate was only utilized as an electron donor at sulfur-reducing conditions. The soda lake sulfidogenesis showed obligately alkaliphilic pH response matching the in situ conditions. Microbiological analysis showed a domination of three groups of haloalkaliphilic autotrophic SRB belonging to the order Desulfovibrionales with a clear tendency to grow by thiosulfate disproportionation even at salt-saturating conditions. Few novel representatives of the order Desulfobacterales capable of heterotrophic growth with VFA and alcohols at high pH and moderate salinity have also been found, while acetate oxidation was a function of a specialized group of haloalkaliphilic sulfur-reducing bacteria belonging to the phylum Chrysiogenetes.

DimitryYSorokin

2011-03-01

365

Titanospirillum velox: A huge, speedy, sulfur-storing spirillum from Ebro Delta microbial mats  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A long (20–30 ?m), wide (3–5 ?m) microbial-mat bacterium from the Ebro Delta (Tarragona, Spain) was grown in mixed culture and videographed live. Intracellular elemental sulfur globules and unique cell termini were observed in scanning-electron-microprobe and transmission-electron micrographs. A polar organelle underlies bundles of greater than 60 flagella at each indented terminus. These Gram-negative bacteria bend, flex, and swim in a spiral fashion; they translate at speeds greater t...

Guerrero, Ricardo; Haselton, Aaron; Sole?, Mo?nica; Wier, Andrew; Margulis, Lynn

1999-01-01

366

Sodium sulfur battery: An overview  

Science.gov (United States)

High theoretical specific energy values are expected from batteries with low equivalent weight reactants and large electronegativity differences. Alkali metals, acting as the negative electrode, and the chalcogenides as the positive electrode, potentially could produce a battery with high specific energy density. Weber and Kummer demonstrated such a battery using sodium and sulfur as the two electrode materials. The key to the development of this battery was the discovery that solid electrolytes such as beta-alumina conducts sodium ions efficiently. Since then other glassy materials have been shown to be adequate conductors of sodium ions as well. Based on these two types of electrolytes, three approaches to the design of the sodium/sulfur battery have evolved. This paper provides a brief overview of these design approaches.

Sen, R. K.; Landgrebe, A. L.

1987-01-01

367

Selling the green dream  

Energy Technology Data Exchange (ETDEWEB)

The article discusses the marketing and sales of energy generated from renewable energy sources. To purchase environmental energy in the USA, the consumer need do no more than tick a box on a sheet of paper. But, it is not just households that opt for green energy: businesses are also willing customers. A factor in the success in selling green energy to big business is that the retail price of wind power can be held constant over periods of several years, whereas fossil fuel prices can fluctuate wildly. Details of sources and sales of the top ten companies selling green energy are given.

Wood, E.

2005-08-01

368

Green Light Pulse Oximeter  

Energy Technology Data Exchange (ETDEWEB)

A reflectance pulse oximeter that determines oxygen saturation of hemoglobin using two sources of electromagnetic radiation in the green optical region, which provides the maximum reflectance pulsation spectrum. The use of green light allows placement of an oximetry probe at central body sites (e.g., wrist, thigh, abdomen, forehead, scalp, and back). Preferably, the two green light sources alternately emit light at 560 nm and 577 nm, respectively, which gives the biggest difference in hemoglobin extinction coefficients between deoxyhemoglobin, RHb, and oxyhemoglobin, HbO.sub.2.

Scharf, John Edward (Oldsmar, FL)

1998-11-03

369

Green Chemistry Teaching Resources  

Science.gov (United States)

The American Chemical Society (ACS) has created these excellent resources via the Green Chemistry Institute and the ACS Education Division. The goal of these materials is "to increase awareness and understanding of Green Chemistry principles, alternatives, practices, and benefits within traditional educational institutions and among practicing scientists." In the Online Resources section, visitors will find downloadable pocket guides to basic green chemistry principles, "Greener Education Materials for Chemists" from the University of Oregon, and more. Perhaps the best section of the site is Activities and Experiments, where visitors can look over activities like "Gassing Up Without Air Pollution" and "Cleaning Up With Atom Economy."

370

??????? (Bacteria???????): Pseudomonas syringae  

Full Text Available Pseudomonas syringae ATCC 19310 = PD 184 Janse, J.D., J.H.J. Derks, B.E. Spit, and W.R. van der Tuin. 1992. Classification of fluorescent soft rot Pseudomononas bacteria, including P. marginali

371

??????? (Bacteria???????): Pseudomonas cichorii  

Full Text Available Pseudomonas cichorii PD 377,PD 468 Janse, J.D., J.H.J. Derks, B.E. Spit, and W.R. van der Tuin. 1992. Classification of fluorescent soft rot Pseudomononas bacteria, including P. marginali

372

??????? (Bacteria???????): Pseudomonas cichorii  

Full Text Available Pseudomonas cichorii ATCC 10857 Janse, J.D., J.H.J. Derks, B.E. Spit, and W.R. van der Tuin. 199 2. Classification of fluorescent soft rot Pseudomononas bacteria, including P. marginali

373

??????? (Bacteria???????): Pseudomonas viridiflava  

Full Text Available Pseudomonas viridiflava NCPPB 635 Janse, J.D., J.H.J. Derks, B.E. Spit, and W.R. van der Tuin. 1 992. Classification of fluorescent soft rot Pseudomononas bacteria, including P. marginali

374

??????? (Bacteria???????): Pseudomonas tolaasii  

Full Text Available Pseudomonas tolaasii NCPPB 2192 = PD 210 Janse, J.D., J.H.J. Derks, B.E. Spit, and W.R. van der Tuin. 1992. Classification of fluorescent soft rot Pseudomononas bacteria, including P. marginali

375

Cultivation Media for Bacteria  

Science.gov (United States)

Common bacteriological culture media (tryptic soy agar, chocolate agar, Thayer-Martin agar, MacConkey agar, eosin-methylene blue agar, hektoen agar, mannitol salt agar, and sheep blood agar) are shown uninoculated and inoculated with bacteria.

American Society For Microbiology;

2009-12-08

376

??????? (Bacteria???????): Capnocytophaga canimorsus  

Full Text Available Capnocytophaga canimorsus Daneshvar, M.I., D.G. Hollis, and C.W. Moss. 1991. Chemical characteri zation of clinical isolates which are similar to CDC group DF-3 bacteria. J. Clin. Micro

377

The effect of green tea mouthwash (Camellia sinensis) on wound healing following periodontal crown lengthening surgery; a double blind randomized controlled trial  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Green tea has been used as a traditional medicine since 2700 BC and several studies have shown that green tea polyphenols inhibit the growth of oral and periodontal pathogenic bacteria and can improve oral and gingival health. In this clinical study we investigated the effect of green tea mouthwash on microbial dental plaque and gingival inflammation following periodontal surgery. A total of 34 crown lengthening surgeries were included in this study. After removing periodontal dressing, green...

Ali Forouzanfar; Hamid Reza Arab; Hooman Shafaee; Majid Reza Mokhtari; Shayan Golestani

2012-01-01

378

Antimicrobial activity of blue-green and green algae  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The methanolic extract of a blue-green alga and two green algae have been investigated for in vitro antimicrobial activity against Proteus vulgaris, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Aspergillus niger, Aspergillus flavus and Rhizopus nigricans using agar cup-plate method. Blue-green alga, namely, Microchaete tenera ; and green algae, namely, Nitella tenuissima and Sphaeroplea annulina , showed significant antibacteri...

Prashantkumar P; Angadi S; Vidyasagar G

2006-01-01

379

Growth of Acidithiobacillus ferrooxidans ATCC 23270 in thiosulfate under oxygen-limiting conditions generates extracellular sulfur globules by means of a secreted tetrathionate hydrolase  

Directory of Open Access Journals (Sweden)

Full Text Available Production of sulfur globules during sulfide or thiosulfate oxidation is a characteristic feature of some sulfur bacteria. Although their generation has been reported in Acidithiobacillus ferrooxidans, its mechanism of formation and deposition, as well as the physiological significance of these globules during sulfur compounds oxidation, are currently unknown. Under oxygen sufficient conditions (OSC, A. ferrooxidans oxidizes thiosulfate to tetrathionate, which accumulates in the culture medium. Tetrathionate is then oxidized by a tetrathionate hydrolase (TTH generating thiosulfate, elemental sulfur and sulfate as final products. We report here a massive production of extracellular conspicuous sulfur globules in thiosulfate-grown A. ferrooxidans cultures shifted to oxygen-limiting conditions (OLC. Concomitantly with sulfur globule deposition, the extracellular concentration of tetrathionate greatly diminished and sulfite accumulated in the culture supernatant. A. ferrooxidans cellular TTH activity was negligible in OLC incubated cells, indicating that this enzymatic activity was not responsible for tetrathionate disappearance. On the other hand, supernatants from both OSC- and OLC-incubated cells showed extracellular TTH activity, which most likely accounted for tetrathionate consumption in the culture medium. The extracellular TTH activity described here: (i gives experimental support to the TTH-driven model for hydrophilic sulfur globule generation, (ii explains the extracellular location of A. ferrooxidans sulfur deposits, and (iii strongly suggests that the generation of sulfur globules in A. ferrooxidans corresponds to an early step during its adaptation to an anaerobic lifestyle.

AlbertoParadela

2011-04-01

380

Polymerization of commercial Mexican sulfur  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: English Abstract in spanish Las características físicas del azufre cambian en forma notable cuando su temperatura es de alrededor de 160°C: a) Un cambio de cuatro órdenes de magnitud en la viscosidad laminar, en un intervalo de 25°C. b) Cambios en su densidad y en la velocidad del sonido. c) Su color se hace más oscuro y su ín [...] dice de refracción y permitividad eléctrica, muestran un mínimo, d) Además existe un interés especial en el proceso de polimerización que ocurre en torno a esa temperatura, debido a que el azufre polimerizado puede tener aplicaciones industriales. Estudios realizados en azufre extra puro (99.999 %) han permitido avanzar en el entendimiento de estos fenómenos, pero aún no se tiene una explicación completa de ellos. Las propiedades del azufre cambian mucho por la presencia de impurezas y gases disueltos en él, por lo que, si se quieren utilizar sus características para uso industrial, hay que proceder con azufre comercial y no de gran pureza. En este trabajo se reportan algunos resultados de espectroscopia infrarroja, espectroscopia Raman y difracción de rayos-X obtenidos en experimentos diseñados para obtener la polimerización de azufre mexicano comercial. Abstract in english As it is well known, the physical characteristics of sulfur exhibit a wide range of interesting phenomena around 160°C (1): a) A shear viscosity change of four orders of magnitude over a 25°C interval (2). b) Changes in density and in sound velocity. c) Its color becomes darker and its refractive in [...] dex and dielectric permittivity reach a minimum. d) Of special interest, because of its possible industrial applications, is the polymerization process that occurs at around 160°C. Studies made in ultra pure sulfur (99.999%) have shed some light on this phenomenon, but a coherent picture is still missing. The properties of sulfur are strongly affected by impurities and dissolved gases, so that a great deal of care is necessary when performing these experiments. If the purpose is to take advantages of these properties for industrial applications, one must rule out the use of ultra-pure sulfur and think in terms of a simple process with a commercial substance. In this work we shall report some infrared spectroscopy, Raman spectroscopy and X-ray diffraction results obtained in our attempts at the polymerization of commercial Mexican sulfur.

R.W, Gómez; J.L, Pérez M; V, Marquina; R, Ridaura; M.L, Marquina.

 
 
 
 
381

Radiolysis of Sulfuric Acid, Sulfuric Acid Monohydrate, and Sulfuric Acid Tetrahydrate and Its Relevance to Europa  

Science.gov (United States)

We report laboratory studies on the 0.8 MeV proton irradiation of ices composed of sulfuric acid (H2SO4), sulfuric acid monohydrate (H2SO4 H2O), and sulfuric acid tetrahydrate (H2SO4 4H2O) between 10 and 180 K. Using infrared spectroscopy, we identify the main radiation products as H2O, SO2, (S2O3)x, H3O+, HSO4(exp -), and SO4(exp 2-). At high radiation doses, we find that H2SO4 molecules are destroyed completely and that H2SO4 H2O is formed on subsequent warming. This hydrate is significantly more stable to radiolytic destruction than pure H2SO4, falling to an equilibrium relative abundance of 50% of its original value on prolonged irradiation. Unlike either pure H2SO4 or H2SO4 H2O, the loss of H2SO4 4H2O exhibits a strong temperature dependence, as the tetrahydrate is essentially unchanged at the highest irradiation temperatures and completely destroyed at the lowest ones, which we speculate is due to a combination of radiolytic destruction and amorphization. Furthermore, at the lower temperatures it is clear that irradiation causes the tetrahydrate spectrum to transition to one that closely resembles the monohydrate spectrum. Extrapolating our results to Europa s surface, we speculate that the variations in SO2 concentrations observed in the chaotic terrains are a result of radiation processing of lower hydration states of sulfuric acid and that the monohydrate will remain stable on the surface over geological times, while the tetrahydrate will remain stable in the warmer regions but be destroyed in the colder regions, unless it can be reformed by other processes, such as thermal reactions induced by diurnal cycling.

Loeffler, M. J.; Hudson, R. L.; Moore, M. H.; Carlson, R. W.

2011-01-01

382

Radiolysis of sulfuric acid, sulfuric acid monohydrate, and sulfuric acid tetrahydrate and its relevance to Europa  

Science.gov (United States)

We report laboratory studies on the 0.8 MeV proton irradiation of ices composed of sulfuric acid (H 2SO 4), sulfuric acid monohydrate (H 2SO 4·H 2O), and sulfuric acid tetrahydrate (H 2SO 4·4H 2O) between 10 and 180 K. Using infrared spectroscopy, we identify the main radiation products as H 2O, SO 2, (S 2O 3) x, H 3O +, HSO4-, and SO42-. At high radiation doses, we find that H 2SO 4 molecules are destroyed completely and that H 2SO 4·H 2O is formed on subsequent warming. This hydrate is significantly more stable to radiolytic destruction than pure H 2SO 4, falling to an equilibrium relative abundance of 50% of its original value on prolonged irradiation. Unlike either pure H 2SO 4 or H 2SO 4·H 2O, the loss of H 2SO 4·4H 2O exhibits a strong temperature dependence, as the tetrahydrate is essentially unchanged at the highest irradiation temperatures and completely destroyed at the lowest ones, which we speculate is due to a combination of radiolytic destruction and amorphization. Furthermore, at the lower temperatures it is clear that irradiation causes the tetrahydrate spectrum to transition to one that closely resembles the monohydrate spectrum. Extrapolating our results to Europa's surface, we speculate that the variations in SO 2 concentrations observed in the chaotic terrains are a result of radiation processing of lower hydration states of sulfuric acid and that the monohydrate will remain stable on the surface over geological times, while the tetrahydrate will remain stable in the warmer regions but be destroyed in the colder regions, unless it can be reformed by other processes, such as thermal reactions induced by diurnal cycling.

Loeffler, M. J.; Hudson, R. L.; Moore, M. H.; Carlson, R. W.

2011-09-01

383

Effect of different sulfur levels from various sources on brassica napus growth and soil sulfur fractions  

International Nuclear Information System (INIS)

A two year field study was conducted at two different locations in northern rain fed Punjab, Pakistan to assess the effect of different rates of sulfur application from various sources on soil sulfur fractions and growth of Brassica napus. The treatments included three sulfur sources i. e., single super phosphate, ammonium sulfate and gypsum each applied at five different rates (0, 10, 20, 30 and 40 kg S ha/sup -1/ ). Sulfur application had a significant positive effect on the growth and yield parameters of Brassica napus. Among the sulfur sources ammonium sulfate resulted in maximum increase in plant growth and yield parameters, followed by single super phosphate. Sulfur content and uptake by crop plants was significantly higher with ammonium sulfate application as compared to other two sulfur sources. Sulfur application also exerted a significant positive effect on different S fractions in the soils. On an average, 18.0% of the applied sulfur got incorporated into CaCl/sub 2/ extractable sulfur fraction, while 15.6% and 35.5% entered into adsorbed and organic sulfur fractions in the soils, respectively. The value cost ratio increased significantly by sulfur application up to 30 kg ha/sup -1/. Among sulfur sources, ammonium sulfate performed best giving the highest net return. (author)

2012-08-01

384

DsrR, a Novel IscA-Like Protein Lacking Iron- and Fe-S-Binding Functions, Involved in the Regulation of Sulfur Oxidation in Allochromatium vinosum? †  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the purple sulfur bacterium Allochromatium vinosum, the reverse-acting dissimilatory sulfite reductase (DsrAB) is the key enzyme responsible for the oxidation of intracellular sulfur globules. The genes dsrAB are the first and the gene dsrR is the penultimate of the 15 genes of the dsr operon in A. vinosum. Genes homologous to dsrR occur in a number of other environmentally important sulfur-oxidizing bacteria utilizing Dsr proteins. DsrR exhibits sequence similarities to A-type scaffolds, ...

Grimm, Frauke; Cort, John R.; Dahl, Christiane

2010-01-01

385

Green Product Innovation Strategy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Over the last decades, companies have started to incorporate green issues in product innovation strategies. This dissertation studies green product innovation strategy, its antecedents and its outcomes. A three-stage approach is followed. In the first stage, the topic is explored and a preliminary research framework is identified. The second stage involves theory-building, using case studies and literature interactively. This stage leads to the identification of elelments of product innovatio...

Driessen, P. H.

2005-01-01

386

Green Certificates For Electricity  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper studies implementation and use of Tradable Green Certificates in a multi-market equilibrium framework. The system of Tradable Green Certificates is designed to induce substitution from polluting fuels to renewable, i.e. non-polluting, fuels in electricity generation, and hence alleviate the climate warming problem. Our basic model is in line with Amundsen and Mortensen (2001) but we also include cost uncertainty and the social welfare analysis into our study. The model consis...

Seppa?la?, Minna

2003-01-01

387

POT for Harraby Green  

POT for Harraby Green Back to station POT Data for: Petteril at Harraby Green (76010) Note: Place the mouse cursor over a column heading to view a description of the data in that column Rank Date Time Stage Flow Rating Source Ref Comments 153 28/10/1970 21:00 0.850 18.91 In Range Mfiche 16b 154 26/11…

388

POT for Broad Green  

POT for Broad Green Back to station POT Data for: Bumpstead Brook at Broad Green (36010) Note: Place the mouse cursor over a column heading to view a description of the data in that column Rank Date Time Stage Flow Rating Source Ref Comments 3 16/09/1968 00:00 -8888.880 21.00 Protcd. CEH POTS 26-6-78…

389

Green growth and transport  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Transport figures prominently on green growth agendas. The reason is twofold. First, transport has major environmental impacts in terms of greenhouse gas emissions, local air emissions and noise. And managing congestion more effectively is part of the broader agenda for more sustainable development and better use of resources invested in infrastructure. Second, a large part of public expenditure to stimulate green growth is directed at transport sector industries. This concerns most notably a...

Perkins, Stephen

2011-01-01

390

Coordinate green growth  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Green economic growth needs a shared sense of direction if it is to lead to a more sustainable future under climate change. Studies on green innovation and societal transformation show that uncoordinated initiatives are unlikely to be an effective way “to get the ball rolling and to ‘learn by doing’” (Nature 468, 477; 2010). First, socio-technical transformations, such as the transition from fossil fuels to renewable-energy sources, will re...

Alkemade, F.; Hekkert, M. P.

2010-01-01

391

Solution for Green Computing  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Environmental and energy conservation issues have taken center stage in the global business arena in recent years. The reality of rising en­ergy costs and their impact on international affairs coupled with the increased concern over the global warming climate crisis and other en­vironmental issues have shifted the social and economic consciousness of the business community. Green Computing, or Green IT, is the practice of implementing policies and procedures that improve the efficiency of c...

2010-01-01

392

From green architecture to architectural green : Facade versus space  

DEFF Research Database (Denmark)

The paper investigates the topic of green architecture from an architectural point of view and not an energy point of view. The purpose of the paper is to establish a debate about the architectural language and spatial characteristics of green architecture. In this light, green becomes an adjective that describes the architectural exclusivity of this particular architecture genre. The adjective green expresses architectural qualities differentiating green architecture from none-green architecture. Currently, adding trees and vegetation to the buildingâ??s facade is the main architectural characteristics of green architecture. The paper argues that this greenification of facades is insufficient. The green is only a skin cladding the exterior envelope without having a spatial significance. Through the paper it is proposed to flip the order of words from green architecture to architectural green. Architectural green could signify green architecture with inclusive interrelations between green and space, built andunbuilt, inside and outside. The aim of the term is to reflect a new focus in green architecture â?? its architectural performance. Ecological issues are not underestimated or ignored, but so far they have overshadowed the architectural potential of green architecture. The paper questions how a green space should perform, look like and function. Two examples are chosen to demonstrate thorough integrations between green and space. The examples are public buildings categorized as pavilions. One is Dutch pavilion at Hannover (MVRDV, 2000). The second is MFO Park (Burckhardt + Partner AG, 2002). By the means of the examples, possible characteristics and performance of architectural green are discussed and evaluated. The paper argues that the notion of green as an architectural quality is not limited to the architecture of pavilions and can be applied in other architectural forms and functions. The paper ends by questioning the potential of architectural green in urbanity.

Earon, Ofri

393

Toward the green economy: Assessing countries' green power  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The green power potential of a country is a central factor in the transformation to a green economy. This paper argues that green power will become a decisive factor for global change. Green power combines sustainability, innovation and power into one concept. By merging insights from political science, economics and innovation research, this paper develops a multidimensional, multilevel concept of green power that takes both resources and processes into account. A first empirical assessment ...

Never, Babette

2013-01-01

394

Natural sulfur emissions into the atmosphere  

Energy Technology Data Exchange (ETDEWEB)

Natural atmospheric sulfur emission rates are reviewed for important components of the sulfur cycle. A summary of emission estimates is provided for vegetation, coastal and wetland ecosystems, inland soils, and oceanic environments. A brief discussion of sea salt sulfate, aeolian sources, volcanic activity, and biomass burning is also included. The emissions from plants and inland soils, may play a significant role in global sulfur cycling and very little work has been reported covering this subject. Large uncertainties continue to exist in the identity and the emission rates of the sulfur compounds and thus it is not reasonable to extrapolate these data in an attempt to balance the global sulfur cycle. Moreover interactions of enhanced anthropogenic activity with various components of the sulfur cycle need to be considered. 105 refs.

Aneja, V.P. (North Carolina State Univ., Raleigh (USA))

1990-04-01

395

Increased value of refined high sulfur coal  

Energy Technology Data Exchange (ETDEWEB)

Sulfur removal from high sulfur coal has several objectives including: a) reduction of the atmospheric load that contributes to the problem of acid precipitation; b) reduction of ash, which contributes to decreased energy transfer in boilers, as well as ash disposal; and c) alleviation of the social and economic dislocations related to uneven geographical distribution of sulfur in coal reserves. Cost in relation to the value of refined coal will govern the development of an emerging coal refining industry. Estimation of the premium paid by power companies for coal with a low sulfur content is a good estimate of the value that will be added as the result of refining. Estimates of premiums paid in 1984 are $28,65/t ($26 per st) for reduction of total sulfur from 3% to 1% S and greater than $28.65/t ($26 per st) for removal below 1% sulfur.

Dugan, P.R.

1987-08-01

396

Sulfur isotope composition of selected Polish coals  

Energy Technology Data Exchange (ETDEWEB)

Literature studies show that there are few data on sulfur isotope ratio in available the Polish coals. Elaboration of a method for the separation of sulfur from coal and measurement of sulfur isotope ratio of Polish coals is the scope of this work. The aim of the study was the preparation of coal samples and extraction of the particular form of sulfur. The stable compounds (Ag{sub 2}S and BaSO{sub 4}) were converted into sulfur dioxide. Sulfur isotope ratio in the gas phase was determined using a mass spectrometer. Samples were taken from selected Polish coal mines. Hard coal from Upper Silesia Basin, one sample from the Bogdanka coal-mine and one sample of lignite from the Belchatow coal-mine.

Chmielewski, A.G.; Wierzchnicki, R.; Derda, M.; Mikolajczuk, A.

2002-07-01

397

Sulfur isotope composition of selected Polish Coals  

International Nuclear Information System (INIS)

Literature studies show that there are few data on sulfur isotope ratio in available Polish coals. Elaboration of a method for the separation on sulfur from coal and measurement of sulfur isotope ratio of Polish coals is the scope of this work. The aim of the study was the preparation of coal samples and extraction of the particular form of sulfur. The stable compounds (Ag2S and BaSO4) were converted into sulfur dioxide. Sulfur isotope ratio in the gas phase was determined using a mass spectrometer. Samples were taken from selected Polish coal mines. Hard coal from Upper Silesia Basin, one sample from the Bogdanka coal-mine and one sample of lignite from Belchatow coal-mine. (author)

2001-06-24

398

Kinetics of anaerobic elemental sulfur oxidation by ferric iron in Acidithiobacillus ferrooxidans and protein identification by comparative 2-DE-MS/MS.  

Science.gov (United States)

Elemental sulfur oxidation by ferric iron in Acidithiobacillus ferrooxidans was investigated. The apparent Michaelis constant for ferric iron was 18.6 mM. An absence of anaerobic ferric iron reduction ability was observed in bacteria maintained on elemental sulfur for an extended period of time. Upon transition from ferrous iron to elemental sulfur medium, the cells exhibited similar kinetic characteristics of ferric iron reduction under anaerobic conditions to those of cells that were originally maintained on ferrous iron. Nevertheless, a total loss of anaerobic ferric iron reduction ability after the sixth passage in elemental sulfur medium was demonstrated. The first proteomic screening of total cell lysates of anaerobically incubated bacteria resulted in the detection of 1599 protein spots in the master two-dimensional electrophoresis gel. A set of 59 more abundant and 49 less abundant protein spots that changed their protein abundances in an anaerobiosis-dependent manner was identified and compared to iron- and sulfur-grown cells, respectively. Proteomic analysis detected a significant increase in abundance under anoxic conditions of electron transporters, such as rusticyanin and cytochrome c(552), involved in the ferrous iron oxidation pathway. Therefore we suggest the incorporation of rus-operon encoded proteins in the anaerobic respiration pathway. Two sulfur metabolism proteins were identified, pyridine nucleotide-disulfide oxidoreductase and sulfide-quinone reductase. The important transcription regulator, ferric uptake regulation protein, was anaerobically more abundant. The anaerobic expression of several proteins involved in cell envelope formation indicated a gradual adaptation to elemental sulfur oxidation. PMID:22057833

Kucera, Jiri; Bouchal, Pavel; Cerna, Hana; Potesil, David; Janiczek, Oldrich; Zdrahal, Zbynek; Mandl, Martin

2012-03-01

399

Oxidative stress enhances the expression of sulfur assimilation genes: preliminary insights on the Enterococcus faecalis iron-sulfur cluster machinery regulation  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The Firmicutes bacteria participate extensively in virulence and pathological processes. Enterococcus faecalis is a commensal microorganism; however, it is also a pathogenic bacterium mainly associated with nosocomial infections in immunocompromised patients. Iron-sulfur [Fe-S] clusters are inorgani [...] c prosthetic groups involved in d