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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; Davenport, C

2010-01-01

2

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

3

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

4

Mechanisms and evolution of oxidative sulfur metabolism in green sulfur bacteria  

DEFF Research Database (Denmark)

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 or polysulfide reductase-like complex 3. 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.

Gregersen, Lea Haarup; Bryant, Donald A.

2011-01-01

5

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

6

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

7

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 several 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 ...

Huh, Joonsuk; Saikin, Semion K.; Brookes, Jennifer C.; Valleau, Ste?phanie; Fujita, Takatoshi; Aspuru-guzik, Ala?n

2013-01-01

8

Signature pigments of green sulfur bacteria in lower Pleistocene deposits from the Banyoles lacustrine area (Spain)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Signature pigments of photosynthetic green sulfur bacteria (GSB) were found in ancient sediments collected from an abandoned clay quarry located in the Banyoles lacustrine area (Spain). The sediments belong to the Interglacial Waalian of the lower Pleistocene (0.7–1.5 millions years old) and were deposited after a marshy event occurring during that geologic period. Reverse-phase high performance liquid chromatography (RP-HPLC) analyses of acetone:methanol sediment extracts revealed that the...

Mallorqui?, Noemi?; Arellano, Juan B.; Borrego, Carles M.; Garci?a-gil, L. Jesu?s

2005-01-01

9

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

Science.gov (United States)

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 several 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 among 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 mimics a complete light-harvesting apparatus of green sulfur bacteria. The model contains approximately 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 transfer between collective excited states of pigments can result in robust energy funneling to the initial excitation conditions and temperature changes. Moreover, the same mechanism describes the coexistence of multiple time scales of excitation dynamics frequently observed in ultrafast optical experiments. While our findings support the hypothesis of supertransfer, the model reveals energy transport through multiple channels on different length scales. PMID:24405318

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

2014-02-01

10

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ther...

Tang, Joseph Kuo-hsiang; Saikin, Semion k; Pingali, Sai venkatesh; Enriquez, Miriam m; Huh, Joonsuk; Frank, Harry a; Urban, Volker s; Aspuru-guzik, Alan

2013-01-01

11

217 000-year-old DNA sequences of green sulfur bacteria in Mediterranean sapropels and their implications for the reconstruction of the paleoenvironment.  

Science.gov (United States)

Deep-sea sediments of the eastern Mediterranean harbour a series of dark, organic carbon-rich layers, so-called sapropels. Within these layers, the carotenoid isorenieratene was detected. Since it is specific for the obligately anaerobic phototrophic green sulfur bacteria, the presence of isorenieratene may suggest that extended water column anoxia occurred in the ancient Mediterranean Sea during periods of sapropel formation. Only three carotenoids (isorenieratene, beta-isorenieratene and chlorobactene) are typical for green sulfur bacteria and thus do not permit to differentiate between the approximately 80 known phylotypes. In order to reconstruct the paleoecological conditions in more detail, we searched for fossil 16S rRNA gene sequences of green sulfur bacteria employing ancient DNA methodology. 540 bp-long fossil sequences could indeed be amplified from up to 217 000-year-old sapropels. In addition, such sequences were also recovered from carbon-lean intermediate sediment layers deposited during times of an entirely oxic water column. Unexpectedly, however, all the recovered 16S rRNA gene sequences grouped with freshwater or brackish, rather than truly marine, types of green sulfur bacteria. It is therefore feasible that the molecular remains of green sulfur bacteria originated from populations which thrived in adjacent freshwater or estuarine coastal environments rather than from an indigenous pelagic population. PMID:17227428

Coolen, Marco J L; Overmann, Jörg

2007-01-01

12

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

13

Theoretical characterization of excitation energy transfer in chlorosome light-harvesting antennae from green sulfur bacteria.  

Science.gov (United States)

We present a theoretical study of excitation dynamics in the chlorosome antenna complex of green photosynthetic bacteria based on a recently proposed model for the molecular assembly. Our model for the excitation energy transfer (EET) throughout the antenna combines a stochastic time propagation of the excitonic wave function with molecular dynamics simulations of the supramolecular structure and electronic structure calculations of the excited states. We characterized the optical properties of the chlorosome with absorption, circular dichroism and fluorescence polarization anisotropy decay spectra. The simulation results for the excitation dynamics reveal a detailed picture of the EET in the chlorosome. Coherent energy transfer is significant only for the first 50 fs after the initial excitation, and the wavelike motion of the exciton is completely damped at 100 fs. Characteristic time constants of incoherent energy transfer, subsequently, vary from 1 ps to several tens of ps. We assign the time scales of the EET to specific physical processes by comparing our results with the data obtained from time-resolved spectroscopy experiments. PMID:24504540

Fujita, Takatoshi; Huh, Joonsuk; Saikin, Semion K; Brookes, Jennifer C; Aspuru-Guzik, Alán

2014-06-01

14

Temperature and carbon assimilation regulate the chlorosome biogenesis in green sulfur bacteria.  

Science.gov (United States)

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 C. tepidum grows slower and incorporates fewer 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 homologs with smaller side chains, (c) blue-shifted Qy absorption maxima, and (d) a sigmoid-shaped circular dichroism spectra. Using a theoretical model, we analyze how the observed spectral modifications can be associated with structural changes of BChl aggregates inside the chlorosome. Our report suggests a mechanism of metabolic regulation for chlorosome biogenesis. PMID:24047985

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

2013-09-17

15

Large-scale distribution and activity patterns of an extremely low-light-adapted population of green sulfur bacteria in the Black Sea.  

Science.gov (United States)

The Black Sea chemocline represents the largest extant habitat of anoxygenic phototrophic bacteria and harbours a monospecific population of Chlorobium phylotype BS-1. High-sensitivity measurements of underwater irradiance and sulfide revealed that the optical properties of the overlying water column were similar across the Black Sea basin, whereas the vertical profiles of sulfide varied strongly between sampling sites and caused a dome-shaped three-dimensional distribution of the green sulfur bacteria. In the centres of the western and eastern basins the population of BS-1 reached upward to depths of 80 and 95 m, respectively, but were detected only at 145 m depth close to the shelf. Using highly concentrated chemocline samples from the centres of the western and eastern basins, the cells were found to be capable of anoxygenic photosynthesis under in situ light conditions and exhibited a photosynthesis-irradiance curve similar to low-light-adapted laboratory cultures of Chlorobium BS-1. Application of a highly specific RT-qPCR method which targets the internal transcribed spacer (ITS) region of the rrn operon of BS-1 demonstrated that only cells at the central station are physiologically active in contrast to those at the Black Sea periphery. Based on the detection of ITS-DNA sequences in the flocculent surface layer of deep-sea sediments across the Black Sea, the population of BS-1 has occupied the major part of the basin for the last decade. The continued presence of intact but non-growing BS-1 cells at the periphery of the Black Sea indicates that the cells can survive long-distant transport and exhibit unusually low maintenance energy requirements. According to laboratory measurements, Chlorobium BS-1 has a maintenance energy requirement of approximately 1.6-4.9.10(-15) kJ cell(-1) day(-1) which is the lowest value determined for any bacterial culture so far. Chlorobium BS-1 thus is particularly well adapted to survival under the extreme low-light conditions of the Black Sea, and can be used as a laboratory model to elucidate general cellular mechanisms of long-term starvation survival. Because of its adaptation to extreme low-light marine environments, Chlorobium BS-1 also represents a suitable indicator for palaeoceanography studies of deep photic zone anoxia in ancient oceans. PMID:20236170

Marschall, Evelyn; Jogler, Mareike; Hessge, Uta; Overmann, Jörg

2010-05-01

16

Sulfur bacteria in wastewater stabilization ponds periodically affected by the 'red-water' phenomenon.  

Science.gov (United States)

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 rRNA gene and of different functional genes involved in microbial sulfur metabolism (dsrB, aprA, and pufM). Analyses of the 16S rRNA revealed a relatively high microbial diversity where Proteobacteria, Chlorobi, Bacteroidetes, and Cyanobacteria constitute the major bacterial groups. The dsrB and aprA gene analysis revealed the presence of deltaproteobacterial sulfate-reducing bacteria (i.e., Desulfobacter and Desulfobulbus), while the analysis of 16S rRNA, aprA, and pufM genes assigned the sulfur-oxidizing bacteria community to the photosynthetic representatives belonging to the Chlorobi (green sulfur bacteria) and the Proteobacteria (purple sulfur and non sulfur bacteria) phyla. These results point on the diversity of the metabolic processes within this wastewater plant and/or the availability of sulfate and diverse electron donors. PMID:22354366

Belila, Abdelaziz; Abbas, Ben; Fazaa, Imed; Saidi, Neila; Snoussi, Mejdi; Hassen, Abdennaceur; Muyzer, Gerard

2013-01-01

17

Oxidative metabolism of inorganic sulfur compounds by bacteria.  

Science.gov (United States)

The history of the elucidation of the microbiology and biochemistry of the oxidation of inorganic sulfur compounds in chemolithotrophic bacteria is briefly reviewed, and the contribution of Martinus Beijerinck to the study of sulfur-oxidizing bacteria highlighted. Recent developments in the biochemistry, enzymology and molecular biology of sulfur oxidation in obligately and facultatively lithotrophic bacteria are summarized, and the existence of at least two major pathways of thiosulfate (sulfur and sulfide) oxidation confirmed. These are identified as the 'Paracoccus sulfur oxidation' (or PSO) pathway and the 'S4intermediate' (or S4I) pathway respectively. The former occurs in organisms such as Paracoccus (Thiobacillus) versutus and P. denitrificans, and possibly in Thiobacillus novellus and Xanthobacter spp. The latter pathway is characteristic of the obligate chemolithotrophs (e.g. Thiobacillus tepidarius, T. neapolitanus, T. ferrooxidans, T. thiooxidans) and facultative species such as T. acidophilus and T. aquaesulis, all of which can produce or oxidize tetrathionate when grown on thiosulfate. The central problem, as yet incompletely resolved in all cases, is the enzymology of the conversion of sulfane-sulfur (as in the outer [S-] atom of thiosulfate [-S-SO3-]), or sulfur itself, to sulfate, and whether sulfite is involved as a free intermediate in this process in all, or only some, cases. The study of inorganic sulfur compound oxidation for energetic purposes in bacteria (i.e. chemolithotrophy and sulfur photolithotrophy) poses challenges for comparative biochemistry. It also provides evidence of convergent evolution among diverse bacterial groups to achieve the end of energy-yielding sulfur compound oxidation (to drive autotrophic growth on carbon dioxide) but using a variety of enzymological systems, which share some common features. Some new data are presented on the oxidation of 35S-thiosulfate, and on the effect of other anions (selenate, molybdate, tungstate, chromate, vanadate) on sulfur compound oxidation, including observations which relate to the roles of polythionates and elemental sulfur as intermediates. PMID:9049021

Kelly, D P; Shergill, J K; Lu, W P; Wood, A P

1997-02-01

18

Influence of Purple Sulfur Bacteria on the biogeochemistry of Carbon and Sulfur Isotopes in Crystal Lake, OH  

Science.gov (United States)

Crystal Lakes are a series of four interconnected mesotrophic, moulin-induced glacial lakes in west-central Ohio. The study site, Main Lake (a.k.a. Crystal Lake), is the largest and deepest lake among them. It is about 5 ha with a maximum depth of 11.9 meters and a mean depth of 3.8 meters. Thermal stratification develops during the warmer months. Photosynthesis, which preferentially uptakes lighter isotopes, is the primary pathway for carbon and sulfur isotope fractionation in natural waters. Photosynthesizers present at Crystal Lake include green algae, diatoms, cyanobacteria, and purple sulfur bacteria (PSB). Phytoplankton growth is limited by nutrient availability, influencing the extent of fractionation. Purple sulfur bacteria (PSB) utilize sulfide as an electron donor instead of water. The layer of concentrated PSB population exists between oxic and anoxic water in lakes where sufficient light and sulfide are present. These bacteria impact the levels of several sulfur compounds and isotopic composition within lake systems by oxidizing sulfide to sulfate. Field parameters collected in warmer months show turbidity and chlorophyll peaks around 6 m with variations caused by temperature, light, and nutrient availability. The dissolved oxygen minimum and the redox and sulfate maxima generally correspond with the turbidity and chlorophyll peaks, indicating the presence of a PSB layer. This layer occurs at the boundary between the metalimnion and hypolimnion. Sulfide concentrations increased from a maximum of 0.02 mg/L in May to a maximum of 9.25 mg/L in August. In May sulfide was only found at 10.4 m and below while in August it was present at 6 m and below. Sulfate values remain relatively constant with a maximum at the layer of PSB, then decline with depth where Sulfide is abundant. ?13C-DIC values peak at 6 m corresponding with the layer of PSB. This peak may be due to the influence of PSB on carbon isotope fractionation. The carbon isotope composition of phytoplankton is to be determined. The isotopic composition of different sulfur species, SO42- , S0 and S2-, and seasonal variation are being analyzed. Exploration of the potential role of PSB on sulfur isotopic composition and their affect on the sulfur isotopic distribution in the lake system is in progress. Currently, no sulfur isotopic composition measurements through PSB or systematic studies of the impact of fractionation between sulfate and sulfide by PSB exist in the literature. Since PSB affect the equilibrium of the system, more than just sulfate and sulfide should be considered.

Meyer, A.; Nichols, D. L.; Cheng, S.

2013-12-01

19

Diversity of anoxygenic phototrophic sulfur bacteria in the microbial mats of the Ebro Delta: a combined morphological and molecular approach.  

Science.gov (United States)

The diversity of purple and green sulfur bacteria in the multilayered sediments of the Ebro Delta was investigated. Specific oligonucleotide primers for these groups were used for the selective amplification of 16S rRNA gene sequences. Subsequently, amplification products were separated by denaturing gradient gel electrophoresis and sequenced, which yielded a total of 32 sequences. Six of the sequences were related to different cultivated members of the green sulfur bacteria assemblage, whereas seven fell into the cluster of marine or halophilic Chromatiaceae. Six sequences were clustered with the family Ectothiorhodospiraceae, three of the six being closely related to chemotrophic bacteria grouped together with Halorhodospira genus, and the other three forming a group related to the genus Ectothiorhodospira. The last thirteen sequences constituted a cluster where no molecular isolate from microbial mats has so far been reported. Our results indicate that the natural diversity in the ecosystem studied has been significantly underestimated in the past and point out the presence of novel species not related to all known purple sulfur bacteria. Furthermore, the detection of green sulfur bacteria, after only an initial step of enrichment, suggests that -- with the appropriate methodology -- several genera, such as Prosthecochloris, could be established as regular members of marine microbial mats. PMID:16329919

Martínez-Alonso, Maira; Van Bleijswijk, Judith; Gaju, Núria; Muyzer, Gerard

2005-05-01

20

Ametryne and Prometryne as Sulfur Sources for Bacteria  

Science.gov (United States)

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], methylsulfonic acid, and sodium sulfate could also be used as sulfur sources. Utilization of a compound was quantified as the growth yield per mole of sulfur supplied. Yields were about 6 kg of protein per mol of sulfur. The product of the desulfuration of an s-triazine was identified as the corresponding hydroxy-derivative. This is the first substantiated report of the utilization of these s-triazines as sulfur sources by bacteria. PMID:16345988

Cook, Alasdair M.; Hütter, Ralf

1982-01-01

 
 
 
 
21

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

22

Förster 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 Förster theory of energy transfer. PMID:11536509

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

1992-08-14

23

The role of bacteria and mycorrhiza in plant sulfur supply  

Science.gov (United States)

Plant growth is highly dependent on bacteria, saprophytic, and mycorrhizal fungi which facilitate the cycling and mobilization of nutrients. Over 95% of the sulfur (S) in soil is present in an organic form. Sulfate-esters and sulfonates, the major forms of organo-S in soils, arise through deposition of biological material and are transformed through subsequent humification. Fungi and bacteria release S from sulfate-esters using sulfatases, however, release of S from sulfonates is catalyzed by a bacterial multi-component mono-oxygenase system. The asfA gene is used as a key marker in this desulfonation process to study sulfonatase activity in soil bacteria identified as Variovorax, Polaromonas, Acidovorax, and Rhodococcus. The rhizosphere is regarded as a hot spot for microbial activity and recent studies indicate that this is also the case for the mycorrhizosphere where bacteria may attach to the fungal hyphae capable of mobilizing organo-S. While current evidence is not showing sulfatase and sulfonatase activity in arbuscular mycorrhiza, their effect on the expression of plant host sulfate transporters is documented. A revision of the role of bacteria, fungi and the interactions between soil bacteria and mycorrhiza in plant S supply was conducted. PMID:25566295

Gahan, Jacinta; Schmalenberger, Achim

2014-01-01

24

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

25

Quantitative proteomics of Chlorobaculum tepidum : insights into the sulfur metabolism of a phototrophic green sulfur bacterium  

DEFF Research Database (Denmark)

Chlorobaculum (Cba.) tepidum is a green sulfur bacterium that oxidizes sulfide, elemental sulfur, and thiosulfate for photosynthetic growth. To gain insight into the sulfur metabolism, the proteome of Cba. tepidum cells sampled under different growth conditions has been quantified using a rapid gel-free, filter-aided sample preparation (FASP) protocol with an in-solution isotopic labeling strategy. Among the 2245 proteins predicted from the Cba. tepidum genome, approximately 970 proteins were detected in unlabeled samples, whereas approximately 630-640 proteins were detected in labeled samples comparing two different growth conditions. Wild-type cells growing on thiosulfate had an increased abundance of periplasmic cytochrome c-555 and proteins of the periplasmic thiosulfate-oxidizing SOX enzyme system when compared with cells growing on sulfide. A dsrM mutant of Cba. tepidum, which lacks the dissimilatory sulfite reductase DsrM protein and therefore is unable to oxidize sulfur globules to sulfite, was also investigated. When compared with wild type, the dsrM cells exhibited an increased abundance of DSR enzymes involved in the initial steps of sulfur globule oxidation (DsrABCL) and a decreased abundance of enzymes putatively involved in sulfite oxidation (Sat-AprAB-QmoABC). The results show that Cba. tepidum regulates the cellular levels of enzymes involved in sulfur metabolism and other electron-transferring processes in response to the availability of reduced sulfur compounds.

Falkenby, Lasse Gaarde; Szymanska, Monika

2011-01-01

26

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

27

Detecting oxidized contaminants in water using sulfur-oxidizing bacteria.  

Science.gov (United States)

For the rapid and reliable detection of oxidized contaminants (i.e., nitrite, nitrate, perchlorate, dichromate) in water, a novel toxicity detection methodology based on sulfur-oxidizing bacteria (SOB) has been developed. The methodology exploits the ability of SOB to oxidize elemental sulfur to sulfuric acid in the presence of oxygen. The reaction results in an increase in electrical conductivity (EC) and a decrease in pH. When oxidized contaminants were added to the system, the effluent EC decreased and the pH increased due to the inhibition of the SOB. We found that the system can detect these contaminants in the 5-50 ppb range (in the case of NO(3)(-), 10 ppm was detected), which is lower than many whole-cell biosensors to date. At low pH, the oxidized contaminants are mostly in their acid or nonpolar, protonated form which act as uncouplers and make the SOB biosensor more sensitive than other whole-cell biosensors which operate at higher pH values where the contaminants exist as dissociated anions. The SOB biosensor can detect toxicity on the order of minutes to hours which can serve as an early warning so as to not pollute the environment and affect public health. PMID:21417357

Van Ginkel, Steven W; Hassan, Sedky H A; Ok, Yong Sik; Yang, Jae E; Kim, Yong-Seong; Oh, Sang-Eun

2011-04-15

28

Phototropic sulfur and sulfate-reducing bacteria in the chemocline of meromictic Lake Cadagno, Switzerland  

Directory of Open Access Journals (Sweden)

Full Text Available Lake Cadagno, a crenogenic meromictic lake located in the catchment area of a dolomite vein rich in gypsum in the Piora Valley in the southern Alps of Switzerland, is characterized by a compact chemocline with high concentrations of sulfate, steep gradients of oxygen, sulfide and light and a turbidity maximum that correlates to large numbers of bacteria (up to 107 cells ml-1. The most abundant taxa in the chemocline are large- and small-celled purple sulfur bacteria, which account for up to 35% of all bacteria, and sulfate- reducing bacteria that represent up to 23% of all bacteria. Depending on the season, as much as 45% of all bacteria in the chemocline are associated in aggregates consisting of different populations of small-celled purple sulfur bacteria of the genus Lamprocystis (up to 35% of all bacteria and sulfate-reducing bacteria of the family Desulfobulbaceae (up to 12% of all bacteria that are almost completely represented by bacteria closely related to Desulfocapsa thiozymogenes. Their association in aggregates is restricted to small-celled purple sulfur bacteria of the genus Lamprocystis, but not obligate since non-associated cells of bacteria related to D. thiozymogenes are frequently found, especially under limited light conditions in winter and early summer. Aggregate formation and concomitant growth enhancement of isolates of both partners of this association suggests synergistic interactions that might resemble a sulfide-based source-sink relationship between the sulfate-reducing bacterium that is able to sustain growth by a disproportionation of inorganic sulfur compounds (sulfur, thiosulfate, sulfite, with the purple sulfur bacteria acting as a biotic scavenger. The availability of these isolates opens up the door for future studies considering other facets of potential interactions in aggregates since both types of organisms are metabolically highly versatile and interactions may not be limited to sulfur compounds only.

Raffaele PEDUZZI

2004-08-01

29

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 oxygen–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

30

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 oxygen–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

31

[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

32

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

33

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

34

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

35

Subtidal Gastropods Consume Sulfur-Oxidizing Bacteria: Evidence from Coastal Hydrothermal Vents  

Science.gov (United States)

The black abalone (Haliotis cracherodii), a commercially important shallow-water gastropod common off White Point, Southern California, is found frequently at subtidal hydrothermal vents within mats of filamentous sulfur-oxidizing bacteria. Foraging vent abalones actively consume the bacteria and confine their nightly feeding forays to bacterial mats surrounding the vents. The growth of abalones consuming the sulfur bacteria exceeds that of control individuals consuming microalgae and is comparable to reported growth rates of abalones consuming macroalgae. Thus, off White Point, the black abalone may derive a portion of its nutrition from the subsidy of geothermal energy.

Stein, Jeffrey L.

1984-02-01

36

A model of the protein-pigment baseplate complex in chlorosomes of photosynthetic green bacteria  

DEFF Research Database (Denmark)

In contrast to photosynthetic reaction centers, which share the same structural architecture, more variety is found in the light-harvesting antenna systems of phototrophic organisms. The largest antenna system described, so far, is the chlorosome found in anoxygenic green bacteria, as well as in a recently discovered aerobic phototroph. Chlorosomes are the only antenna system, in which the major light-harvesting pigments are organized in self-assembled supramolecular aggregates rather than on protein scaffolds. This unique feature is believed to explain why some green bacteria are able to carry out photosynthesis at very low light intensities. Encasing the chlorosome pigments is a protein-lipid monolayer including an additional antenna complex: the baseplate, a two-dimensional paracrystalline structure containing the chlorosome protein CsmA and bacteriochlorophyll a (BChl a). In this article, we review current knowledge of the baseplate antenna complex, which physically and functionally connects the chlorosome pigments to the reaction centers via the Fenna-Matthews-Olson protein, with special emphasis on the well-studied green sulfur bacterium Chlorobaculum tepidum (previously Chlorobium tepidum). A possible role for the baseplate in the biogenesis of chlorosomes is discussed. In the final part, we present a structural model of the baseplate through combination of a recent NMR structure of CsmA and simulation of circular dichroism and optical spectra for the CsmA-BChl a complex.

Pedersen, Marie Ø; Linnanto, Juha

2010-01-01

37

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

38

Volatile sulfur production by pig cecal bacteria in batch culture and screening inhibitors of sulfate reducing bacteria.  

Science.gov (United States)

We studied the effects of specific inhibitors of methanogenesis (2-bromoethane sulfonate, BES) and sulfate reduction (sodium molybdate) on volatile sulfur production in batch cultures of pig cecal bacteria. The volatile sulfur concentration in headspace gas was determined by flame-photometric detector gas chromatography. BES stimulated production of hydrogen sulfide (H2S) and methanethiol, and sodium molybdate completely inhibited the production of these volatile sulfur compounds. The results indicated that dissimilate sulfate reduction is mainly responsible for volatile sulfur production in the hindgut. Therefore the extracts of herbs, food colors, and aroma chemicals were tested for their inhibitory effects on H2S production by a dissimilatory sulfate-reducing bacteria. Desulfovibrio desulfuricans DSM642. H2S was measured by the chromatography of the headspace gas, using a flame photometric detector. Of 306 herbal extracts tested, 69 extracts from 38 herbs inhibited H2S production at 1.0 mg/mL. Sisymbrium officinale (hedge mustard) was the most potent inhibitor. Six pigments inhibited H2S release. Erythrosine and rose bengal showed inhibitory effects at 0.01 mg/mL. Peppermint oil and 96 aroma chemicals were assayed for their effects on H2S release. Thirty-two aroma chemicals suppressed H2S production at 0.1 mg/mL, and camphene, 1-decanol, and 2-nonanone were effective at 0.01 mg/mL. PMID:11185657

Arakawa, T; Ishikawa, Y; Ushida, K

2000-08-01

39

Structure, Function and Reconstitution of Antenna Complexes of Green Photosynthetic Bacteria  

Energy Technology Data Exchange (ETDEWEB)

Most chlorophyll-type pigments in a photosynthetic organism function as an antenna, absorbing light and transferring excitations to a photochemical reaction center where energy storage takes place by a series of chemical reactions. The green photosynthetic bacteria are characterized by large antenna complexes known as chlorosomes, in which pigment-pigment interactions are of dominant importance. The overall objective of this project is to determine the mechanisms of excitation transfer and regulation of this unique antenna system, including how it is integrated into the rest of the photosynthetic energy transduction apparatus. Techniques that are being used in this research include biochemical analysis, spectroscopy, microscopy, X-ray structural studies, and reconstitution from purified components. Our recent results indicate that the chlorosome baseplate structure, which is the membrane attachment site for the chlorosome to the membrane, is a unique pigment-protein that contains large amounts of carotenoids and small amounts of bacteriochlorophyll a. Reconstitution of directed energy transfer in chlorosomes will be carried out using purified baseplates and oligomeric pigments. The integral membrane B808-866 antenna complex from Chloroflexus aurantiacus and the Fenna-Matthews-Olson protein-reaction center complex from green sulfur bacteria will be characterized by spectroscopic and structural techniques.

Blankenship, Robert E.

2005-06-10

40

The role of sulfur-oxidizing bacteria Thiobacillus thiooxidans in pyrite weathering  

International Nuclear Information System (INIS)

The paper investigates the role of the sulfur-oxidizing bacteria Thiobacillus thiooxidans in pyrite weathering in order to clarify the effects of the bacteria on the dissolution behavior of pyrite and the formation of secondary minerals using Raman spectroscopy and powder X-ray diffraction (XRD) in addition to solution analysis. It was found that T. thiooxidans, when present with the iron-oxidizing bacteria Thiobacillus ferrooxidans, enhanced the dissolution of Fe and S species for pyrite, whereas T. thiooxidans alone did not oxidize pyrite. Enhancement of the consumption of elemental sulfur and regeneration of Fe(II) ions were also observed with T. thiooxidans together with T. ferrooxidans, while this did not occur with T. ferrooxidans alone

 
 
 
 
41

The riboswitch-mediated control of sulfur metabolism in bacteria  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Many operons in Gram-positive bacteria that are involved in methionine (Met) and cysteine (Cys) biosynthesis possess an evolutionarily conserved regulatory leader sequence (S-box) that positively controls these genes in response to methionine starvation. Here, we demonstrate that a feed-back regulation mechanism utilizes S-adenosyl-methionine as an effector. S-adenosyl-methionine directly and specifically binds to the nascent S-box RNA, causing an intrinsic terminator to form and interrupt tr...

Epshtein, Vitaly; Mironov, Alexander S.; Nudler, Evgeny

2003-01-01

42

Detecting endocrine disrupting compounds in water using sulfur-oxidizing bacteria.  

Science.gov (United States)

For the rapid and reliable detection of endocrine disrupting compounds in water, a novel toxicity detection methodology based on sulfur-oxidizing bacteria (SOB) has been developed. The methodology exploits the ability of SOB to oxidize elemental sulfur to sulfuric acid in the presence of oxygen. The reaction results in an increase in electrical conductivity (EC) and a decrease in pH. When endocrine disrupting compounds were added to the system, the effluent EC decreased and the pH increased due to the inhibition of the SOB. We found that the system can detect these chemicals in the 50-200 ppb range, which is lower than many whole-cell biosensors to date. The SOB biosensor can detect toxicity on the order of min to h which can serve as an early warning so as to not pollute the environment and affect public health. PMID:20580056

Van Ginkel, Steven W; Hassan, Sedky H A; Oh, Sang-Eun

2010-09-01

43

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

Science.gov (United States)

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. PMID:17760503

Mussmann, Marc; Hu, Fen Z; Richter, Michael; de Beer, Dirk; Preisler, André; Jørgensen, Bo B; Huntemann, Marcel; Glöckner, Frank Oliver; Amann, Rudolf; Koopman, Werner J H; Lasken, Roger S; Janto, Benjamin; Hogg, Justin; Stoodley, Paul; Boissy, Robert; Ehrlich, Garth D

2007-09-01

44

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

45

Bacteria associated with iron seeps in a sulfur-rich, neutral pH, freshwater ecosystem.  

Science.gov (United States)

The freshwater nature reserve De Bruuk is an iron- and sulfur-rich minerotrophic peatland containing many iron seeps and forms a suitable habitat for iron and sulfur cycle bacteria. Analysis of 16S rRNA gene-based clone libraries showed a striking correlation of the bacterial population of samples from this freshwater ecosystem with the processes of iron reduction (genus Geobacter), iron oxidation (genera Leptothrix and Gallionella) and sulfur oxidation (genus Sulfuricurvum). Results from fluorescence in situ hybridization analyses with a probe specific for the beta-1 subgroup of Proteobacteria, to which the genera Leptothrix and Gallionella belong, and newly developed probes specific for the genera Geobacter and Sulfuricurvum, supported the clone library data. Molecular data suggested members of the epsilonproteobacterial genus Sulfuricurvum as contributors to the oxidation of reduced sulfur compounds in the iron seeps of De Bruuk. In an evaluation of anaerobic dimethyl sulfide (DMS)-degrading activity of sediment, incubations with the electron acceptors sulfate, ferric iron and nitrate were performed. The fastest conversion of DMS was observed with nitrate. Further, a DMS-oxidizing, nitrate-reducing enrichment culture was established with sediment material from De Bruuk. This culture was dominated by dimorphic, prosthecate bacteria, and the 16S rRNA gene sequence obtained from this enrichment was closely affiliated with Hyphomicrobium facile, which indicates that the Hyphomicrobium species are capable of both aerobic and nitrate-driven DMS degradation. PMID:18754044

Haaijer, Suzanne C M; Harhangi, Harry R; Meijerink, Bas B; Strous, Marc; Pol, Arjan; Smolders, Alfons J P; Verwegen, Karin; Jetten, Mike S M; Op den Camp, Huub J M

2008-12-01

46

Revealing biogenic sulfuric acid corrosion in sludge digesters: detection of sulfur-oxidizing bacteria within full-scale digesters.  

Science.gov (United States)

Biogenic sulfuric acid corrosion (BSA) is a costly problem affecting both sewerage infrastructure and sludge handling facilities such as digesters. The aim of this study was to verify BSA in full-scale digesters by identifying the microorganisms involved in the concrete corrosion process, that is, sulfate-reducing (SRB) and sulfur-oxidizing bacteria (SOB). To investigate the SRB and SOB communities, digester sludge and biofilm samples were collected. SRB diversity within digester sludge was studied by applying polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) targeting the dsrB-gene (dissimilatory sulfite reductase beta subunit). To reveal SOB diversity, cultivation dependent and independent techniques were applied. The SRB diversity studies revealed different uncultured SRB, confirming SRB activity and H2S production. Comparable DGGE profiles were obtained from the different sludges, demonstrating the presence of similar SRB species. By cultivation, three pure SOB strains from the digester headspace were obtained including Acidithiobacillus thiooxidans, Thiomonas intermedia and Thiomonas perometabolis. These organisms were also detected with PCR-DGGE in addition to two new SOB: Thiobacillus thioparus and Paracoccus solventivorans. The SRB and SOB responsible for BSA were identified within five different digesters, demonstrating that BSA is a problem occurring not only in sewer systems but also in sludge digesters. In addition, the presence of different SOB species was successfully associated with the progression of microbial corrosion. PMID:25353947

Huber, B; Drewes, J E; Lin, K C; König, R; Müller, E

2014-01-01

47

INFLUENCE OF ELEMENTAL SULFUR, ORGANIC MATTER, SULFUR OXIDIZING BACTERIA AND CABRONITE ALONE OR IN COMBINATION ON COWPEA PLANTS AND THE USED SOIL  

Directory of Open Access Journals (Sweden)

Full Text Available A field experiment was carried out at the Abis Experimental Farm, Faculty of Agriculture, Alexandria University. The soil (clay loam was treated with sulfur oxidizing bacteria (S.O.B., municipal refuse compost (O.M, elemental sulfur (E.S and Cabronite, each alone or in combination. Seeds of cowpea were inoculated with the specific root nodule bacteria (Okadin before planting.According to the obtained results the following results could be concluded:All the used treatments i.e E.S; O.M; Cabronite and S.O.B. each alone or in combination significantly increased the dry weights of cowpea plants and also increased the roots, shoots and seeds as well the used soil content of S, P, K, N, Fe, Mn, Zn and Cu.The application of elemental sulfur with S.O.B. to the soil improved the availability and plant uptake of macro and micro nutrients by cowpea plants as well nutrients content of the used soil.Application of O.M maximized the role of sulfur and S.O.B.It could be concluded that the best treatment which clearly affected growth, nodulation, seed yield and nutrients content of cowpea plants as well as the elemental content of the used soil was elemental sulfur (E.S + organic matter (O.M and sulfur oxidizing bacteria (S.O.B. treatment.

El-Halfawi M. H.

2010-10-01

48

EFFECT OF SOLE AND ASSOCIATIVE ACTIONS OF ELEMENTAL SULFUR AND INOCULATION SULFUR OXIDIZING BACTERIA ON GROWTH AND NUTRIENTS CONTENTS OF PEPPER PLANTS AND THE USED SOILS  

Directory of Open Access Journals (Sweden)

Full Text Available A pot experiment was conducted to study the effect of elemental sulfur (E.S rate (2.5 g/kg soil and sulfur oxidizing bacteria on pepper plant and some chemical properties of two representative soil samples varying in their texture and CaCO3 content. Pepper was grown in Shobrakheet clay loam and Nobaria sandy loam soils for 50 days. Each soil was treated with elemental sulfur (2.5 g kg-1 soil and inoculated with two sulfur oxidizing bacteria (S.O.B. No.8 and S.O.B. ATCC 8158. Elemental sulfur with or without sulfur oxidizing bacteria increased shoot dry weights of pepper plants as compared with control. The highest effect was observed with E.S + ATCC 8158 treatment which resulted in increasing the pepper shoot dry weights from 1.36 to 2.08 g pot-1 with the clay loam soil and from 0.77 to 1.37 g pot-1 with the sandy loam soil. The same treatment resulted in the highest plant content of S, N, P, K and micronutrients.

S. A. Ibrahim

2011-12-01

49

INFLUENCE OF ELEMENTAL SULFUR, ORGANIC MATTER, SULFUR OXIDIZING BACTERIA AND CABRONITE ALONE OR IN COMBINATION ON COWPEA PLANTS AND THE USED SOIL  

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A field experiment was carried out at the Abis Experimental Farm, Faculty of Agriculture, Alexandria University. The soil (clay loam) was treated with sulfur oxidizing bacteria (S.O.B.), municipal refuse compost (O.M), elemental sulfur (E.S) and Cabronite, each alone or in combination. Seeds of cowpea were inoculated with the specific root nodule bacteria (Okadin) before planting.According to the obtained results the following results could be concluded:All the used treatments i.e E.S; O.M; C...

El-Halfawi M. H.; Ibrahim S. A.; Hala Kandil

2010-01-01

50

Preliminary analysis of lipids and fatty acids of green bacteria and Chloroflexus aurantiacus.  

Science.gov (United States)

The complex lipids and fatty acids of the seven type species of green bacteria and three strains of Chloroflexus aurantiacus were analyzed. The green bacteria contained lipids that behaved as cardiolipin and phosphatidylglycerol on thin-layer chromatography. They did not contain phosphatidylethanolamine or phosphatidylserine. Similarly, Chloroflexus contained lipids that behaved as phosphatidylglycerol and phosphatidylinositol on thin-layer chromatography and did not contain phosphatidylethanolamine or phosphatidylserine. The green bacteria contained glycolipids I and II of Constantopoulos and Bloch (monogalactosyldiglyceride and a galactose- and rhamnose-containing diglyceride). Chloroflexus exhibited galactose-containing glycolipids that behaved identically with the mono- and digalactosyldiglycerides of spinach on thin-layer chromatography, and each contained galactose as well as at least one other sugar. The fatty acids of both groups of bacteria consisted entirely of saturated and monounsaturated fatty acids. In the green bacteria, myristic, palmitic, and hexadecenoic acids predominated. In Chloroflexus, palmitic, stearic, and oleic acids predominated. The positions of the double bonds in the monounsaturated fatty acids of Chloroflexus indicated synthesis by the anaerobic pathway. The lipid analyses suggest a close relationship between the green bacteria and Chloroflexus and further suggest that these groups of photosynthetic bacteria are more closely related to the blue-green algae than are the purple bacteria. PMID:4421249

Kenyon, C N; Gray, A M

1974-10-01

51

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

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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

52

Interactions between anaerobic ammonium and sulfur-oxidizing bacteria in a laboratory scale model system.  

Science.gov (United States)

Fixed nitrogen is released by anaerobic ammonium oxidation (anammox) and/or denitrification from (marine) ecosystems. Nitrite, the terminal electron acceptor of the anammox process, occurs in nature at very low concentrations and is produced via (micro)aerobic oxidation of ammonium or nitrate reduction. The coupling of sulfide-dependent denitrification to anammox is particularly interesting because besides hydrogen, sulfide is the most important reductant at the chemocline of anoxic marine basins and is abundant within sediments. Although at ?M concentrations, sulfide may be toxic and inhibiting anammox activity, a denitrifying microorganism could convert sulfide and nitrate at sufficiently high rates to allow anammox bacteria to stay active despite an influx of sulfide. To test this hypothesis, a laboratory scale model system containing a co-culture of anammox bacteria and the autotrophic denitrifier Sulfurimonas denitrificans?DSM1251 was started. Complementary techniques revealed that the gammaproteobacterial Sedimenticola sp. took over the intended role of Su.?denitrificans. A stable coculture of anammox bacteria and Sedimenticola sp. consumed sulfide, nitrate, ammonium and CO2 . Anammox bacteria contributed 65-75% to the nitrogen loss from the reactor. The cooperation between anammox and sulfide-dependent denitrification may play a significant role in environments where sulfur cycling is active and where actual sulfide concentrations stay below ?M range. PMID:24750895

Russ, Lina; Speth, Daan R; Jetten, Mike S M; Op den Camp, Huub J M; Kartal, Boran

2014-11-01

53

Effect of organics and alkalinity on the sulfur oxidizing bacteria (SOB) biosensor.  

Science.gov (United States)

The environmental risk assessment of toxic chemicals in stream water requires the use of a low cost standardized toxicity bioassay. Here, a biosensor for detection of toxic chemicals in stream water was studied using sulfur oxidizing bacteria (SOB) in continuous mode. The biosensor depends on the ability of SOB to oxidize sulfur particles under aerobic conditions to produce sulfuric acid. The reaction results in an increase in electrical conductivity (EC) and a decrease in pH. The biosensor is based on the inhibition of SOB in the presence of toxic chemicals by measuring changes in EC and pH. We found that the SOB biosensor can detect Cr(6+)at a low concentration (50 ppb) which is lower than many whole-cell biosensors. The effect of organic material in real stream water on SOB activity was studied. Due to the presence of mixotrophic SOB, we found that the presence of organic matter increases SOB activity which decreases the biosensor start up period. Low alkalinity (22 mg L(-1) CaCO(3)) increased effluent EC and decreased effluent pH which is optimal for biosensor operation. While at high alkalinity (820 mg L(-1) CaCO(3), the activity of SOB little decreased. We found that system can detect 50 ppb of Cr(6+) at low alkalinity (22 mg L(-1) CaCO(3)) in few hours while, complete inhibition was observed after 35 h of operation at high alkalinity (820 mg L(-1) CaCO(3)). PMID:22840537

Hassan, Sedky H A; Van Ginkel, Steven W; Oh, Sang-Eun

2013-01-01

54

Sulfur oxidation in rice field soil: activity, enumeration, isolation and characterization of thiosulfate-oxidizing bacteria.  

Science.gov (United States)

In rice paddy fields the bulk soil is anoxic, but oxygenated zones occur in the surrounding of the rice roots to where oxygen is transported via the aerenchyma system of the rice plants. In the anaerobic soil compartments sulfate is consumed by sulfate-reducing bacteria. In the rhizosphere the reduced sulfur compounds can be reoxidized by sulfur-oxidizing bacteria. Measurements of the potential activity of thiosulfate-oxidizing bacteria in soil slurries derived from planted rice soil microcosms showed turnover rates of 2-6 mumol d-1 g-dw-1. Thiosulfate was oxidized to sulfate with tetrathionate as intermediate. Most probable number (MPN) enumeration with three aerobic media and one anaerobic nitrate-amended medium showed that thiosulfate-oxidizing bacteria were abundant in paddy soil and in rhizosphere soil at numbers of 10(5) to 10(6) per gram dry weight soil. Nine isolates of S-oxidizing bacteria were obtained from enrichment cultures or from the highest dilutions of the MPN series and were affiliated to four different phylogenetic groups. These isolates were characterized by physiological properties and by comparative 16S rDNA sequence analysis. Three isolates (TA1-AE1, TA1-A1 and TA12-21) were shown to be facultatively chemolithoautotrophic strains of Ancylobacter aquaticus. Three further isolates (Tv6-2b, Z2A-6A and Z4A-2A) were also facultatively chemolithoautotrophic and were affiliated with the Xanthobacter sp. group, probably representing new strains of X. flavus or X. tagetidis. Strain SZ-2111 was phylogenetically related to Bosea thiooxidans. However, the genus Bosea is described as obligately heterotrophic, whereas strain 5Z-2111 was able to grow autotrophically. The isolates 5Z-C1 and TBW3 were obligate chemolithoautotrophs and were closely affiliated with Thiobacillus thioparus. Our results showed that S-oxidizing bacteria were abundant and active in rice paddy soil and consisted of physiologically and phylogenetically diverse populations. PMID:9924825

Stubner, S; Wind, T; Conrad, R

1998-12-01

55

Metabolic adaptation and trophic strategies of soil bacteria - C1- metabolism and sulfur chemolithotrophy in Starkeya novella  

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The highly diverse and metabolically versatile microbial communities found in soil environments are major contributors to the global carbon, nitrogen and sulfur cycles. We have used a combination of genome –based pathway analysis with proteomics and gene expression studies to investigate metabolic adaptation in a representative of these bacteria, Starkeya novella, which was originally isolated from agricultural soil. This bacterium was the first facultative sulfur chemolithoautotroph that w...

UlrikeKappler

2013-01-01

56

Cultured and genetic diversity, and activities of sulfur-oxidizing bacteria in low-temperature hydrothermal fluids of the North Fiji Basin  

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We determined key chemical parameters and thiosulfate oxidation in low-temperature hydrothermal fluids from the North Fiji Basin. In addition, the bacterial diversity (with the main emphasis on sulfur-oxidizing bacteria) was investigated. The hydrothermal fluids had low concentrations of sulfide (up to 50.0 µM) and increased counts of both total bacteria and sulfur-oxidizing bacteria compared to ambient seawater. Pure cultures of bacteria were isolated from these fluids on media suited for a...

Podgorsek, Lilijana; Petri, Ralf; Imhoff, Johannes F.

2004-01-01

57

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

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A green sulfur bacterium, strain JAGS6(T) Was isolated from a marine aquaculture pond located near Kakinada on the east coast of India. Cells of strain JAGS6(T) were Gram-negative, non-motile, coccoid, 1-1.2 mu m in diameter, with prosthecae. Phylogenetic analysis on the basis of 16S rRNA gene sequences showed that strain JAGS6(T) clusters with members of the genus Prosthecochloris and the sequence similarity with the nearest relative, Prosthecochloris vibrioformis, is 96.7%. Cultures of stra...

Kumar, P. A.; Srinivas, T. N. R.; Sasikala, Ch; Ramana, Ch V.; Su?ling, Jo?rg; Imhoff, Johannes F.

2009-01-01

58

EFFECT OF LIGNIN ON ENZYMATIC SACCHARIFICATION OF HARDWOOD AFTER GREEN LIQUOR AND SULFURIC ACID PRETREATMENTS  

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Full Text Available Red maple, sweet gum, trembling aspen, red alder, and Eucalyptus globulus samples were pretreated with dilute sulfuric acid and green liquor before enzymatic saccharification. Substrates showed different levels of delignification and sugar recovery, depending on the applied pretreatments and the syringaldehyde/vanillin ratio (S/V. Three major conclusions were drawn in this research. First, lignin is the greatest contributor to recalcitrance of hardwood to enzymatic saccharification. Second, a high S/V ratio is a useful indicator of high delignification during a pretreatment process. Third, green liquor pretreatment is a promising pretreatment method because of a high delignification degree and sugar recovery. In addition, xylan also contributes to the recalcitrance of hardwoods toward enzymatic saccharification.

Douyong Min,

2012-02-01

59

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

60

Influence of Gamma Radiation in Combination with Biocides on Sulfur Reducing Bacteria  

International Nuclear Information System (INIS)

The counts of sulfur reducing bacteria (SRB) of the water samples collected from a gas treatment plant of a petroleum field in middle delta-Egypt were determined. The data showed a significant counts of (SRB) in the collected samples and there was a mild increase in the bacterial counts through the system stages which revealed the presence of appropriate conditions required for the growth of (SRB) microflora. Three groups of non-oxidizing biocides were screened for their bactericidal activities. It was found that the biocides IA and IB were slightly superior in respect to the antibacterial efficacy compared to their analogues of aldehydic and cationic forms, respectively. So, these biocides were selected for the study of the combined treatment with gamma radiation to maximize the efficiency on sulfate reducing bacteria treatment using the minimum effective dose of both radiation and biocides, and to eliminate their negative impacts, This treatment demonstrated that it is possible to minimize the amount of chemical biocides that are injected into targeted systems and released to the environment by exposing the waste water to ionizing radiation after biocides addition

 
 
 
 
61

Malachite green-INT (MINT) method for determining active bacteria in sewage.  

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A membrane filtration method was developed to determine the proportion of active (respiring) bacteria at various stages of sewage treatment. Samples were incubated in the presence of 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl tetrazolium chloride (INT) and, after fixation, passed through membrane filters. Filters were counterstained with malachite green and then were examined by bright-field microscopy. The contrast between bacteria and the filter background was greatly improved by drying an...

Dutton, R. J.; Bitton, G.; Koopman, B.

1983-01-01

62

Effect of green tea on volatile sulfur compounds in mouth air.  

Science.gov (United States)

Many food products are claimed to be effective in controlling halitosis. Halitosis is caused mainly by volatile sulfur compounds (VSCs) such as H(2)S and CH(3)SH produced in the oral cavity. Oral microorganisms degrade proteinaceous substrates to cysteine and methionine, which are then converted to VSCs. Most treatments for halitosis focus on controlling the number of microorganisms in the oral cavity. Since tea polyphenols have been shown to have antimicrobial and deodorant effects, we have investigated whether green tea powder reduces VSCs in mouth air, and compared its effectiveness with that of other foods which are claimed to control halitosis. Immediately after administering the products, green tea showed the largest reduction in concentration of both H(2)S and CH(3)SH gases, especially CH(3)SH which also demonstrated a better correlation with odor strength than H(2)S; however, no reduction was observed at 1, 2 and 3 h after administration. Chewing gum, mints and parsley-seed oil product did not reduce the concentration of VSCs in mouth air at any time. Toothpaste, mints and green tea strongly inhibited VSCs production in a saliva-putrefaction system, but chewing gum and parsley-seed oil product could not inhibit saliva putrefaction. Toothpaste and green tea also demonstrated strong deodorant activities in vitro, but no significant deodorant activity of mints, chewing gum or parsley-seed oil product were observed. We concluded that green tea was very effective in reducing oral malodor temporarily because of its disinfectant and deodorant activities, whereas other foods were not effective. PMID:18388413

Lodhia, Parth; Yaegaki, Ken; Khakbaznejad, Ali; Imai, Toshio; Sato, Tsutomu; Tanaka, Tomoko; Murata, Takatoshi; Kamoda, Takeshi

2008-02-01

63

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

64

Natural Green Coating Inhibits Adhesion of Clinically Important Bacteria  

Science.gov (United States)

Despite many advances, biomaterial-associated infections continue to be a major clinical problem. In order to minimize bacterial adhesion, material surface modifications are currently being investigated and natural products possess large potential for the design of innovative surface coatings. We report the bioguided phytochemical investigation of Pityrocarpa moniliformis and the characterization of tannins by mass spectrometry. It was demonstrated that B-type linked proanthocyanidins-coated surfaces, here termed Green coatings, reduced Gram-positive bacterial adhesion and supported mammalian cell spreading. The proposed mechanism of bacterial attachment inhibition is based on electrostatic repulsion, high hydrophilicity and the steric hindrance provided by the coating that blocks bacterium-substratum interactions. This work shows the applicability of a prototype Green-coated surface that aims to promote necessary mammalian tissue compatibility, while reducing bacterial colonization. PMID:25655943

Trentin, Danielle S.; Silva, Denise B.; Frasson, Amanda P.; Rzhepishevska, Olena; da Silva, Márcia V.; de L. Pulcini, Elinor; James, Garth; Soares, Gabriel V.; Tasca, Tiana; Ramstedt, Madeleine; Giordani, Raquel B.; Lopes, Norberto P.; Macedo, Alexandre J.

2015-01-01

65

Natural green coating inhibits adhesion of clinically important bacteria.  

Science.gov (United States)

Despite many advances, biomaterial-associated infections continue to be a major clinical problem. In order to minimize bacterial adhesion, material surface modifications are currently being investigated and natural products possess large potential for the design of innovative surface coatings. We report the bioguided phytochemical investigation of Pityrocarpa moniliformis and the characterization of tannins by mass spectrometry. It was demonstrated that B-type linked proanthocyanidins-coated surfaces, here termed Green coatings, reduced Gram-positive bacterial adhesion and supported mammalian cell spreading. The proposed mechanism of bacterial attachment inhibition is based on electrostatic repulsion, high hydrophilicity and the steric hindrance provided by the coating that blocks bacterium-substratum interactions. This work shows the applicability of a prototype Green-coated surface that aims to promote necessary mammalian tissue compatibility, while reducing bacterial colonization. PMID:25655943

Trentin, Danielle S; Silva, Denise B; Frasson, Amanda P; Rzhepishevska, Olena; da Silva, Márcia V; de L Pulcini, Elinor; James, Garth; Soares, Gabriel V; Tasca, Tiana; Ramstedt, Madeleine; Giordani, Raquel B; Lopes, Norberto P; Macedo, Alexandre J

2015-01-01

66

Changes in hydrogen production and polymer accumulation upon sulfur-deprivation in purple photosynthetic bacteria  

Energy Technology Data Exchange (ETDEWEB)

The work investigated physiological conditions directing cellular metabolism toward either H{sub 2}-production or storage polymer accumulation in purple photosynthetic bacteria. Hydrogen-producing cultures of the purple anoxygenic photosynthetic bacterium Rhodospirillum rubrum were resuspended in media lacking sulfur (S) nutrients. S-deprived cultures displayed lack of growth, cessation of bacteriochlorophyll and protein accumulation, and inhibition of H{sub 2} evolution. Cell volume increased substantially and large amounts of polymer were found to accumulate extracellularly. Poly-{beta}-hydroxybutyrate (PHB) content increased about 3.5-fold within 24 h of S-deprivation. Most cells remained viable after 100 h of S-deprivation and cultures were capable of resuming growth and H{sub 2}-production when supplemented with sulfate. Transcript levels, protein amount, and activity of the nitrogenase enzyme, which are responsible for H{sub 2}-production, decreased with a halftime of about 15 h upon S-deprivation. In addition, the nitrogenase NifH subunits were modified by ADP-ribosylation, indicating post-translational inactivation. Comparative aconitase activity measurements of control and S-deprived cells failed to indicate a general stress to Fe-S proteins, as aconitase, a Fe-S protein in the citric acid cycle sensitive to oxidative stress, maintained activity throughout the course of the S-deprivation. In contrast to nifH transcriptional down-regulation, expression of cysK (encoding cysteine synthase) was upregulated in response to S-deprivation. The described physiology is not specific to R. rubrum, as Rhodobacter sphaeroides and Rhodopseudomonas palustris exhibited a similar response to S-deprivation. It is suggested that manipulation of the supply of S-nutrients may serve as a tool for the alternative production of H{sub 2} or PHB in purple photosynthetic bacteria, thus affording opportunities to design photobiological systems that serve in both energy conversion and storage processes. (author)

Melnicki, Matthew R. [Agricultural and Environmental Chemistry, University of California, 111 Koshland Hall, MC-3102, Berkeley, CA 94720 (United States); Eroglu, Ela [Plant and Microbial Biology, University of California, Berkeley, CA 94720-3102 (United States); Melis, Anastasios [Agricultural and Environmental Chemistry, University of California, 111 Koshland Hall, MC-3102, Berkeley, CA 94720 (United States); Plant and Microbial Biology, University of California, Berkeley, CA 94720-3102 (United States)

2009-08-15

67

Expansion of ability of denitrification within the filamentous colorless sulfur bacteria of the genus Thiothrix.  

Science.gov (United States)

Filamentous sulfur bacteria of the genus Thiothrix are able to respire nitrate (NO3-?NO2-) under anaerobic growth. Here, Thiothrix caldifontis (G1(T), G3), Thiothrix unzii (A1(T), TN) and Thiothrix lacustris AS were shown to be capable of further reduction of nitrite and/or nitrous oxides (denitrification). In particular, in the genomes of these strains, excluding T. unzii TN, the nirS gene encoding periplasmic respiratory nitrite reductase was detected, and for T. lacustris AS the nirS expression was confirmed during anaerobic growth. The nirK gene, coding for an alternative nitrite reductase, and the nrfA gene, encoding nitrite reduction to ammonia, were not found in any investigated strains. All Thiothrix species capable of denitrification possess the cnorB gene encoding cytochrome c-dependent NO reductase but not the qnorB gene coding for quinol-dependent NO reductase. Denitrifying capacity ('full' or 'truncated') can vary between strains belonging to the same species and correlates with physical-chemical parameters of the environment such as nitrate, hydrogen sulfide and oxygen concentrations. Phylogenetic analysis revealed the absence of recent horizontal transfer events for narG and nirS; however, cnorB was subjected to gene transfer before the separation of modern species from a last common ancestor of the Thiothrix species. PMID:25074823

Trubitsyn, Ivan V; Belousova, Elena V; Tutukina, Maria N; Merkel, Alexander Y; Dubinina, Galina A; Grabovich, Margarita Y

2014-09-01

68

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

69

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

70

Development of an online sulfur-oxidizing bacteria biosensor for the monitoring of water toxicity.  

Science.gov (United States)

A toxicity monitoring system based on the metabolic properties of sulfur-oxidizing bacteria (SOB) in continuous and fed-batch modes has been applied for the detection of nitrite (NO2 (-)-N). In this study, the effects of different concentrations of NO2 (-)-N (0.1 to 5 mg/L) on the SOB bioreactors were tested. We found that 5 mg/L NO2 (-)-N was very toxic to the SOB bioreactors in both continuous (R1) and fed-batch (R2) modes, showing complete inhibition of SOB activity within 2 h of operation. R1 and R2 were operated in different ways; however, the EC inhibition and recovery patterns were very similar. The EC rate increased with an increasing NO2 (-)-N concentration in both continuous and fed-batch modes. The addition of 5 mg/L NO2 (-)-N in continuous mode decreased the average EC rate by 14.38?±?2.1 ?S/cm/min; while in fed-batch mode, the EC rate decreased by 23 ?S/cm/min. Although the toxicity monitoring system could detect 0.5-5 mg/L NO2 (-)-N, it could not detect 0.1 mg/L NO2 (-)-N in either continuous or fed-batch operation. Thus, the SOB biosensor method presented is useful to detect toxic agents such as NO2 (-)-N within a few minutes or hours. PMID:25253265

Gurung, Anup; Kang, Woo-Chang; Shin, Beom-Soo; Cho, Ju Sik; Oh, Sang-Eun

2014-12-01

71

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

72

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 the 18 isolates examined for antagonistic activity, 3 isolates of Lactobacillus plantarum and one isolate of Enterococcus sp. were able to give distinct zones of inhibition against 5 indicator strains of lactic acid bacteria isolated in this study. Cell free supernatant of Lactobacillus plantarum OL9 was active against Gram-positive bacteria (Lactobacillus, Enterococcus and Propionibacterium and also against one Gram-negative bacteria strain of spoilage significance (Erwinia.Este estudio se emprendió con el objetivo de obtener bacterias del ácido láctico con capacidad para utilizarse como cultivo iniciador en la fermentación de aceitunas. Por esta razón, 32 cepas de bacterias del ácido láctico procedentes de fermentaciones espontáneas de aceitunas verdes se caracterizaron e identificaron en función de criterios morfológicos y bioquímicos. Catorce cepas se identificaron como Lactococcus lactis, 11 cepas como Lactobacillus plantarum y 7 cepas como Enterococcus sp. De las 18 cepas que se examinaron para detectar actividades antagónicas, se encontró que 3 cepas de Lactobacillus plantarum y una de Enterococcus sp. mostraban zonas de inhibición contra 5 cepas indicadoras de bacterias del ácido láctico aisladas en este estudio. El sobrenadante libre de células Lactobacillus plantarum OL9 fue activo contra diversas bacterias Gram-positivas (Lactobacillus, Enterococcus y Propionibacterium y contra una cepa de bacteria Gram-negativa relacionada con alteraciones (Erwinia.

Nour-Eddine, Karam

2004-12-01

73

Solubilization of minerals by bacteria: Electrophoretic mobility of Thiobacillus ferrooxidans in the presence of iron, pyrite, and sulfur  

Energy Technology Data Exchange (ETDEWEB)

Thiobacillus ferrooxidans is an obligate acidophile that respires aerobically on pyrite, elemental sulfur, or soluble ferrous ions. The electrophoretic mobility of the bacterium was determined by laser Doppler velocimetry under physiological conditions. When grown on pyrite or ferrous ions, washed cells were negatively charged at pH 2.0. The density of the negative charge depended on whether the conjugate base was sulfate, perchlorate, chloride, or nitrate. The addition of ferric ions shifted the net charge on the surface asymptotically to a positive value. When grown on elemental sulfur, washed cells were close to their isoelectric point at pH 2.0. Both pyrite and colloidal sulfur were negatively charged under the same conditions. The electrical double layer around the bacterial cells under physiological conditions exerted minimal electrostatic repulsion in possible interactions between the cell and either of its charged insoluble substrates. When Thiobacillus ferrooxidans was mixed with either pyrite or colloidal sulfur at pH 2.0, the mobility spectra of the free components disappeared with time to be replaced with a new colloidal particle whose electrophoretic properties were intermediate between those of the starting components. This new particle had the charge and size properties anticipated for a complex between the bacterium and its insoluble substrates. The utility of such measurements for the study of the interactions of chemolithotrophic bacteria with their insoluble substrates is discussed. 34 refs., 9 figs., 1 tab.

Blake, R.C. II; Shute, E.A.; Howard, G.T. [Meharry Medical College, Nashville, TN (United States)

1994-09-01

74

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

75

Metabolic adaptation and trophic strategies of soil bacteria-C1- metabolism and sulfur chemolithotrophy in Starkeya novella.  

Science.gov (United States)

The highly diverse and metabolically versatile microbial communities found in soil environments are major contributors to the global carbon, nitrogen, and sulfur cycles. We have used a combination of genome -based pathway analysis with proteomics and gene expression studies to investigate metabolic adaptation in a representative of these bacteria, Starkeya novella, which was originally isolated from agricultural soil. This bacterium was the first facultative sulfur chemolithoautotroph that was isolated and it is also able to grow with methanol and on over 39 substrates as a heterotroph. However, using glucose, fructose, methanol, thiosulfate as well as combinations of the carbon compounds with thiosulfate as growth substrates we have demonstrated here that contrary to the previous classification, S. novella is not a facultative sulfur chemolitho- and methylotroph, as the enzyme systems required for these two growth modes are always expressed at high levels. This is typical for key metabolic pathways. In addition enzymes for various pathways of carbon dioxide fixation were always expressed at high levels, even during heterotrophic growth on glucose or fructose, which suggests a role for these pathways beyond the generation of reduced carbon units for cell growth, possibly in redox balancing of metabolism. Our results then indicate that S. novella, a representative of the Xanthobacteraceae family of methylotrophic soil and freshwater dwelling bacteria, employs a mixotrophic growth strategy under all conditions tested here. As a result the contribution of this bacterium to either carbon sequestration or the release of climate active substances could vary very quickly, which has direct implications for the modeling of such processes if mixotrophy proves to be the main growth strategy for large populations of soil bacteria. PMID:24146664

Kappler, Ulrike; Nouwens, Amanda S

2013-01-01

76

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

Energy Technology Data Exchange (ETDEWEB)

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.

Chistyakova, N. I., E-mail: nchistyakova@yandex.ru; Rusakov, V. S.; Nazarova, K. A.; Koksharov, Yu. A. [M.V. Lomonosov Moscow State University, Faculty of Physics (Russian Federation); Zavarzina, D. G. [Russian Academy of Sciences, Institute of Microbiology (Russian Federation); Greneche, J.-M. [Universite du Maine, Laboratoire de Physique de l' Etat Condense, UMR CNRS 6087 (France)

2008-02-15

77

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

78

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

International Nuclear Information System (INIS)

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 ?-D-glucuronide (X-Gluc) as substrates. The biodegradation capacity of the selected strains of each species was confirmed by HPLC analysis. (Author).

79

Abundance and diversity of organohalide-respiring bacteria in lake sediments across a geographical sulfur gradient.  

Science.gov (United States)

Across the U.S. Upper Midwest, a natural geographical sulfate gradient exists in lakes. Sediment grab samples and cores were taken to explore whether this sulfur gradient impacted organohalide-respiring Chloroflexi in lake sediments. Putative organohalide-respiring Chloroflexi were detected in 67 of 68 samples by quantitative polymerase chain reaction. Their quantities ranged from 3.5 × 10(4) to 8.4 × 10(10) copies 16S rRNA genes g(-1) dry sediment and increased in number from west to east, whereas lake sulfate concentrations decreased along this west-to-east transect. A terminal restriction fragment length polymorphism (TRFLP) method was used to corroborate this inverse relationship, with sediment samples from lower sulfate lakes containing both a higher number of terminal restriction fragments (TRFs) belonging to the organohalide-respiring Dehalococcoidetes, and a greater percentage of the TRFLP amplification made up by Dehalococcoidetes members. Statistical analyses showed that dissolved sulfur in the porewater, measured as sulfate after oxidation, appeared to have a negative impact on the total number of putative organohalide-respiring Chloroflexi, the number of Dehalococcoidetes TRFs, and the percentage of the TRFLP amplification made up by Dehalococcoidetes. These findings point to dissolved sulfur, presumably present as reduced sulfur species, as a potentially controlling factor in the natural cycling of chlorine, and perhaps as a result, the natural cycling of some carbon as well. PMID:23240654

Krzmarzick, Mark J; McNamara, Patrick J; Crary, Benjamin B; Novak, Paige J

2013-05-01

80

Isolation of Sulfur Reducing and Oxidizing Bacteria Found in Contaminated Drywall  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Drywall from China has been reported to release sulfur producing products which are corrosive to metals, result in noxious odors, and represent a significant health risk. It has been reported that these emissions produce medical symptoms such as respiratory or asthma type problems, sinusitis, gastrointestinal disorders, and vision problems in home owners and their household pets. We report here a method of identifying a causative agent for these emissions by sampling affected gypsum wallboard...

Guilford, Frederick T.; Sutton, John S.; Kilburn, Kaye H.; Vincent Bolton; John Shane; Straus, David C.; Hooper, Dennis G.

2010-01-01

 
 
 
 
81

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 on...

Nualsri, C.; Chuenchit, S.; Maneechai, P.; Petcharat, V.

2005-01-01

82

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

Science.gov (United States)

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

83

Memory-assisted exciton diffusion in the chlorosome light-harvesting antenna of green sulfur bacteria  

CERN Document Server

Chlorosomes are likely the largest and most efficient natural light-harvesting photosynthetic antenna systems. They are composed of large numbers of bacteriochlorophylls organized into supramolecular aggregates. We explore the microscopic origin of the fast excitation energy transfer in the chlorosome using the recently-resolved structure and atomistic-detail simulations. Despite the dynamical disorder effects on the electronic transitions of the bacteriochlorophylls, our simulations show that the exciton delocalizes over the entire aggregate in about 200 fs. The memory effects associated to the dynamical disorder assist the exciton diffusion through the aggregates and enhance the diffusion coefficients as a factor of two as compared to the model without memory. Furthermore, exciton diffusion in the chlorosome is found to be highly anisotropic with the preferential transfer towards the baseplate, which is the next functional element in the photosynthetic system.

Fujita, Takatoshi; Saikin, Semion K; Aspuru-Guzik, Alan

2012-01-01

84

Theoretical characterization of excitation energy transfer in chlorosome light-harvesting antennae from green sulfur bacteria  

CERN Document Server

Chlorosomes are the largest and most efficient natural light-harvesting antenna systems. They contain thousands of pigment molecules - bacteriochlorophylls (BChls)- that are organized into supramolecular aggregates and form a very efficient network for excitonic energy migration. Here, we present a theoretical study of excitation energy transfer (EET) in the chlorosome based on experimental evidence of the molecular assembly. Our model for the exciton dynamics throughout the antenna combines a stochastic time propagation of the excitonic wave function with molecular dynamics simulations of supramolecular structure, and electronic structure calculations of the excited states. The simulation results reveal a detailed picture of the EET in the chlorosome. Coherent energy transfer is significant only for the first 50 fs after the initial excitation, and the wavelike motion of the exciton is completely damped at 100 fs. Characteristic time constants of incoherent energy transfer, subsequently, vary from 1 ps to se...

Fujita, Takatoshi; Saikin, Semion K; Brookes, Jennifer C; Aspuru-Guzik, Alan

2013-01-01

85

Retreived bacteria from Noctiluca miliaris (green) bloom of the northeastern Arabian Sea  

Science.gov (United States)

In recent years, seasonal blooms of the dinoflagellate Noctiluca miliaris have appeared in the open-waters of the northern Arabian Sea (NAS). This study provides the first characterization of bacteria from a seasonal bloom of green Noctiluca of NAS (20°N-17°N and 64°E-70°E), during the spring-inter-monsoon cruise of Sagar Sampada 253, in March 2007. Bacterial growth as assessed by most-probable number (MPN) and plate counts, revealed `variable-physiotypes' over a wide range of salinities (0%-25% w/v NaCl), pH levels (5-8.5), and organic nutrient strengths, in comparison to non-bloom waters. MPN indices of bacteria in surface waters of bloom stations *DWK and *PRB, corresponded to (3.08-4.41)×103 cells/mL at 3.5% NaCl (w/v), and (2.82-9.49)×102 cells/mL at 25% (w/v) NaCl in tryptone-yeast extract broth (TYE). Plate counts were (1.12-4)×106 CFU/mL at 0% (w/v) NaCl, (1.28-3.9)×106 CFU/mL at 3.5% (w/v) NaCl, and (0.4-7)×104 CFU/mL at 25% NaCl (w/v) on TYE. One-tenth-strength Zobell's gave (0.6-3.74)×105 CFU/mL at pH 5 to (3.58-7.5)×105 CFU/mL at pH 8.5. These bacteria were identified to the genera Bacillus, Cellulomonas, Staphylococcus, Planococcus, Dietzia, Virgibacillus, Micrococcus, Sporosarcinae, Leucobacter, and Halomonas. The identity of three strains (GUFBSS253N2, GUFBSS253N30, and GUFBSS253N84) was confirmed through 16S rDNA sequence homology as Bacillus cohnii, Bacillus flexus, and Bacillus cereus. The ˜2-3-fold higher plate counts of culturable bacteria from the open-waters of the NAS indicate that these bacteria could critically determine the biogeochemical dynamics of the bloom and its milieu. The role of these bacteria in sustaining/terminating the bloom is under evaluation.

Basu, Subhajit; Matondkar, S. G. Prabhu; Furtado, Irene

2013-01-01

86

Metal mobilization by iron- and sulfur-oxidizing bacteria in a multiple extreme mine tailings in the Atacama Desert, Chile.  

Science.gov (United States)

The marine shore sulfidic mine tailings dump at the Chañaral Bay in the Atacama Desert, northern Chile, is characterized by extreme acidity, high salinity, and high heavy metals concentrations. Due to pyrite oxidation, metals (especially copper) are mobilized under acidic conditions and transported toward the tailings surface and precipitate as secondary minerals (Dold, Environ. Sci. Technol. 2006, 40, 752-758.). Depth profiles of total cell counts in this almost organic-carbon free multiple extreme environment showed variable numbers with up to 10(8) cells g(-1) dry weight for 50 samples at four sites. Real-time PCR quantification and bacterial 16S rRNA gene diversity analysis via clone libraries revealed a dominance of Bacteria over Archaea and the frequent occurrence of the acidophilic iron(II)- and sulfur-oxidizing and iron(III)-reducing genera Acidithiobacillus, Alicyclobacillus, and Sulfobacillus. Acidophilic chemolithoautotrophic iron(II)-oxidizing bacteria were also frequently found via most-probable-number (MPN) cultivation. Halotolerant iron(II)-oxidizers in enrichment cultures were active at NaCl concentrations up to 1 M. Maximal microcalorimetrically determined pyrite oxidation rates coincided with maxima of the pyrite content, total cell counts, and MPN of iron(II)-oxidizers. These findings indicate that microbial pyrite oxidation and metal mobilization preferentially occur in distinct tailings layers at high salinity. Microorganisms for biomining with seawater salt concentrations obviously exist in nature. PMID:23373853

Korehi, H; Blöthe, M; Sitnikova, M A; Dold, B; Schippers, A

2013-03-01

87

Sulfur Isotropic Studies of Archean Slate and Graywacke from Northern Minnesota: Evidence for the Existence of Sulfate Reducing Bacteria  

Science.gov (United States)

Sulfur isotopic studies of pyrite from metasediments in the 2.6 b.y. old Deer Lake greenstone sequence, Minnesota, were conducted in order to evaluate the possible importance of sulfate reducing bacteria in sulfide formation. Pyrite occurs as ovules up to 2 cm in diameter within graphitic slates, and as fine disseminations in metagraywacke units. SEM studies indicate the pyrite is framboidal in morphology. Delta notation values of pyrite from the Deer Lake sediments range from -2.3 to 11.1 0/00, with a peak at approximately +2 o/oo. Isotopic data is consistent with either high temperature inorganic reduction of circulating seawater sulfate, or low temperature bacterial reduction. However, the lack of sulfide bands or massive occurrences in the sediments, the restriction of pyrite mineralization to the sediments, and the absence of evidence for hot spring activity suggest that a diagenetic origin of pyrite is more feasible. Sulfide in such an environment would be produced principally by the action of sulfate reducing bacteria.

Ripley, E. M.; Nicol, D. L.

1979-01-01

88

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

89

Insights into the Genome of Large Sulfur Bacteria Revealed by Analysis of Single Filaments  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 wh...

Mußmann, Marc; Hu, Fen Z.; Richter, Michael; Beer, Dirk; Preisler, Andre?; Jørgensen, Bo B.; Huntemann, Marcel; Glo?ckner, Frank Oliver; Amann, Rudolf; Koopman, Werner J. H.; Lasken, Roger S.; Janto, Benjamin; Hogg, Justin; Stoodley, Paul; Boissy, Robert

2007-01-01

90

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

91

A diverse assemblage of indole-3-acetic acid producing bacteria associate with unicellular green algae.  

Science.gov (United States)

Microalgae have tremendous potential as a renewable feedstock for the production of liquid transportation fuels. In natural waters, the importance of physical associations and biochemical interactions between microalgae and bacteria is generally well appreciated, but the significance of these interactions to algal biofuels production have not been investigated. Here, we provide a preliminary report on the frequency of co-occurrence between indole-3-acetic acid (IAA)-producing bacteria and green algae in natural and engineered ecosystems. Growth experiments with unicellular algae, Chlorella and Scenedesmus, revealed IAA concentration-dependent responses in chlorophyll content and dry weight. Importantly, discrete concentrations of IAA resulted in cell culture synchronization, suggesting that biochemical priming of cellular metabolism could vastly improve the reliability of high density cultivation. Bacterial interactions may have an important influence on algal growth and development; thus, the preservation or engineered construction of the algal-bacterial assembly could serve as a control point for achieving low input, reliable production of algal biofuels. PMID:24879600

Bagwell, Christopher E; Piskorska, Magdalena; Soule, Tanya; Petelos, Angela; Yeager, Chris M

2014-08-01

92

Natural polysulfides- reactive sulfur species from Allium with applications in medicine and agriculture  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Natural sulfur compounds from plants, bacteria, fungi and animals frequently exhibit interesting biological activities, such as antioxidant, antimicrobial and anticancer activity. Considering the recent developments in medicine (e.g. oxidative stress in ageing, antibiotic resistant bacteria, and selective anticancer agents) and Agriculture (e.g. 'green'; pesticides), several of these compounds have become the focus of interdisciplinary research. Among the various sulfur agents isolated to dat...

Anwar, Awais

2009-01-01

93

Hydrogen-producing purple non-sulfur bacteria isolated from the trophic lake Averno (Naples, Italy)  

Energy Technology Data Exchange (ETDEWEB)

Seventeen purple non-sulfur bacterial strains, isolated from the trophic lake Averno, Naples, Italy, were phylogenetically classified and their H{sub 2}-producing performances were tested utilizing various synthetic substrates and the fermentation broth derived from the spontaneous fermentation of vegetable residues. All the strains showed the capability to produce hydrogen on at least one of the four carbon substrates tested (malic, lactic, acetic and succinic acid). On lactate, Rhodopseudomonas palustris strain AV33 showed the best maximum production rate (50.7 {+-} 2.6 mL (H{sub 2}) L{sup -1} h{sup -1}), with a mean rate, calculated on the whole period of production, of 17.9 mL {+-} 0.7 (H{sub 2}) L{sup -1} h{sup -1}. In the presence of acetate, AV33 produced only few mL of H{sub 2}, but intracellularly accumulated poly-{beta}-hydroxybutyrate up to a concentration of 21.4 {+-} 3.4% (w/w) of cell dry weight. Rp. palustris AV33 also produced H{sub 2} on the fermentation broth supplemented with Fe, with a maximum production rate of 16.4 {+-} 2.3 mL (H{sub 2}) L{sup -1} h{sup -1} and a conversion yield of 44.2%. (author)

Bianchi, Lucia; Mannelli, Francesca; Viti, Carlo; Adessi, Alessandra; De Philippis, Roberto [Department of Agricultural Biotechnology, University of Florence, Piazzale delle Cascine 24, I 50144 Florence (Italy)

2010-11-15

94

Iron sulfides and sulfur species produced at hematite surfaces in the presence of sulfate-reducing bacteria 1  

Science.gov (United States)

In the presence of sulfate-reducing bacteria ( Desulfovibrio desulfuricans) hematite (?-Fe 2O 3) dissolution is affected potentially by a combination of enzymatic (hydrogenase) reduction and hydrogen sulfide oxidation. As a consequence, ferrous ions are free to react with excess H 2S to form insoluble ferrous sulfides. X-ray photoelectron spectra indicate binding energies similar to ferrous sulfides having pyrrhotite-like structures (Fe2 p3/2 708.4 eV; S2 p3/2 161.5 eV). Other sulfur species identified at the surface include sulfate, sulfite and polysulfides. Thin film X-ray diffraction identifies a limited number of peaks, the principal one of which may be assigned to the hexagonal pyrrhotite (102) peak (d = 2.09 Å; 2? = 43.22°), at the hematite surface within 3 months exposure to sulfate-reducing bacteria (SRB). High-resolution transmission electron microscopy identifies the presence of a hexagonal structure associated with observed crystallites. Although none of the analytical techniques employed provide unequivocal evidence as to the nature of the ferrous sulfide formed in the presence of SRB at hematite surfaces, we conclude from the available evidence that a pyrrhotite stiochiometry and structure is the best description of the sulfides we observe. Such ferrous sulfide production is inconsistent with previous reports in which mackinawite and greigite were products of biological sulfate reduction (Rickard 1969a; Herbert et al., 1998; Benning et al., 1999). The apparent differences in stoichiometry may be related to sulfide activity at the mineral surface, controlled in part by H 2S autooxidation in the presence of iron oxides. Due to the relative stability of pyrrhotite at low temperatures, ferrous sulfide dissolution is likely to be reduced compared to the more commonly observed products of SRB activity. Additionally, biogenic pyrrhotite formation will also have implications for geomagnetic field behavior of sediments.

Neal, Andrew L.; Techkarnjanaruk, Somkiet; Dohnalkova, Alice; McCready, David; Peyton, Brent M.; Geesey, Gill G.

2001-01-01

95

Energy transfer kinetics in whole cells and isolated chlorosomes of green photosynthetic bacteria.  

Science.gov (United States)

Time-resolved fluorescence spectroscopy and global data analysis techniques have been used to study the flow of excitations in antennae of the green photosynthetic bacteria Chloroflexus aurantiacus and Chlorobium vibrioforme f. thiosulfatophilum. The transfer of energy from bacteriochlorophyll (BChl) c in Chloroflexus or BChl d in Chlorobium to BChl a 795 was resolved in both whole cells and isolated chlorosomes. In Chloroflexus, the decay of excitations in BChl c occurs in ?16 ps and a corresponding rise in BChl a emission at 805 nm is detected in global analyses. This band then decays in 46 ps in whole cells due to energy transfer into the membrane. The 805 nm fluorescence in isolated chlorosomes shows a fast decay component similar to that of whole cells, which is consistent with trapping by residual membrane antenna complexes. In Chlorobium, the kinetics are sensitive to the presence of oxygen. Under anaerobic conditions, BChl d decays in 66 ps while the lifetime shortens to 11 ps in aerobic samples. The effect is reversible and occurs in both whole cells and isolated chlorosomes. Emission from BChl a is similarly affected by oxygen, indicating that oxidant-induced quenching can occur from all chlorosome pigments. PMID:24420408

Causgrove, T P; Brune, D C; Wang, J; Wittmershaus, B P; Blankenship, R E

1990-10-01

96

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 antimicrobial 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. PMID:24011199

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

2013-10-01

97

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

98

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

99

Documentation of Auxotrophic Mutation in Blue-Green Bacteria: Characterization of a Tryptophan Auxotroph in Agmenellum quadruplicatum  

Science.gov (United States)

A tryptophan-requiring auxotroph of Agmenellum quadruplicatum strain BG1, a species of blue-green bacteria, was isolated by means of a nitrosoguanidine-penicillin procedure. Its growth characteristics were determined, and the enzymological block was identified in the A activity of tryptophan synthetase. Starvation of the auxotroph for tryptophan resulted in the derepression of the synthesis of all five enzymes. The first four enzymes derepressed 2- to 3-fold, and tryptophan synthetase B derepressed 20-fold. In the parental prototroph, BG1, anthranilate synthetase was active in crude extracts with ammonia as the amino donor reactant, but not with glutamine. Images PMID:4204902

Ingram, Lonnie O.; Pierson, Duane; Kane, James F.; Van Baalen, C.; Jensen, Roy A.

1972-01-01

100

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

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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

 
 
 
 
101

Two exopolyphosphatases with distinct molecular architectures and substrate specificities from the thermophilic green-sulfur bacterium Chlorobium tepidum TLS.  

Science.gov (United States)

The genome of the thermophilic green-sulfur bacterium Chlorobium tepidum TLS possesses two genes encoding putative exopolyphosphatases (PPX; EC 3.6.1.11), namely CT0099 (ppx1, 993 bp) and CT1713 (ppx2, 1557 bp). The predicted polypeptides of 330 and 518 aa residues are Ppx-GppA phosphatases of different domain architectures - the largest one has an extra C-terminal HD domain - which may represent ancient paralogues. Both ppx genes were cloned and overexpressed in Escherichia coli BL21(DE3). While CtPPX1 was validated as a monomeric enzyme, CtPPX2 was found to be a homodimer. Both PPX homologues were functional, K(+)-stimulated phosphohydrolases, with an absolute requirement for divalent metal cations and a marked preference for Mg(2+). Nevertheless, they exhibited remarkably different catalytic specificities with regard to substrate classes and chain lengths. Even though both enzymes were able to hydrolyse the medium-size polyphosphate (polyP) P13-18 (polyP mix with mean chain length of 13-18 phosphate residues), CtPPX1 clearly reached its highest catalytic efficiency with tripolyphosphate and showed substantial nucleoside triphosphatase (NTPase) activity, while CtPPX2 preferred long-chain polyPs (>300 Pi residues) and did not show any detectable NTPase activity. These catalytic features, taken together with the distinct domain architectures and molecular phylogenies, indicate that the two PPX homologues of Chl. tepidum belong to different Ppx-GppA phosphatase subfamilies that should play specific biochemical roles in nucleotide and polyP metabolisms. In addition, these results provide an example of the remarkable functional plasticity of the Ppx-GppA phosphatases, a family of proteins with relatively simple structures that are widely distributed in the microbial world. PMID:24969471

Albi, Tomás; Serrano, Aurelio

2014-09-01

102

Stimulation of Cell Division by Croton Oil in Blue-Green Bacteria  

Science.gov (United States)

The potent tumor-promoting agent croton oil, which has been shown previously to be strongly mitogenic in mammalian cells, stimulates cell division in snake mutants of the blue-green bacterium Agmenellum quadruplicatum. Images PMID:4196260

Ingram, Lonnie O'Neal; Fisher, W. D.

1973-01-01

103

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

104

Sub-Micrometer-Scale Mapping of Magnetite Crystals and Sulfur Globules in Magnetotactic Bacteria Using Confocal Raman Micro-Spectrometry  

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The ferrimagnetic mineral magnetite is biomineralized by magnetotactic microorganisms and a diverse range of animals. Here we demonstrate that confocal Raman microscopy can be used to visualize chains of magnetite crystals in magnetotactic bacteria, even though magnetite is a poor Raman scatterer and in bacteria occurs in typical grain sizes of only 35–120 nm, well below the diffraction-limited optical resolution. When using long integration times together with low laser power (<0.25 mW) t...

Eder, Stephan H. K.; Gigler, Alexander M.; Hanzlik, Marianne; Winklhofer, Michael

2014-01-01

105

Antibacterial activity of Green Seaweed Caulerpa racemosa from Takalar Waters against pathogenic bacteria promoting ice-ice diseases in the agar-producing red algae Gracilaria verrucosa.  

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The Ice-ice disease caused by bacterial pathogens which attack the algae tissue resulted white and brittle of seaweed thallus on red seaweed Gracilaria verrucosa farming. Study of antibacterial activity of green seaweed Caulerpa racemosa against the pathogens has been done using method include isolation of bacteria, pathogenicity test with Koch's postulates method, characterization of ice-ice bacteria, extraction of Caulerpa racemosa, and antibacterial test by agar diffusion method. The res...

Zainuddin, Elmi Nurhaidah; Anshary, Hilal; Huyyirnah1); Hiola, Ridha

2012-01-01

106

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

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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

107

Solubilization of Minerals by Bacteria: Electrophoretic Mobility of Thiobacillus ferrooxidans in the Presence of Iron, Pyrite, and Sulfur  

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Thiobacillus ferroxidans is an obligate acidophile that respires aerobically on pyrite, elemental sulfur, or soluble ferrous ions. The electrophoretic mobility of the bacterium was determined by laser Doppler velocimetry under physiological conditions. When grown on pyrite or ferrous ions, washed cells were negatively charged at pH 2.0. The density of the negative charge depended on whether the conjugate base was sulfate, perchlorate, chloride, or nitrate. The addition of ferric ions shifted ...

Blake, Robert C.; Shute, Elizabeth A.; Howard, Gary T.

1994-01-01

108

green  

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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

109

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

110

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

111

Sulfur and phosphorus distribution between liquid iron and magnesia-saturated slag in molecular hydrogen/water atmosphere relevant to a novel green ironmaking technology  

Science.gov (United States)

As an integral part of a research project which aimed to develop a novel green ironmaking process, an experimental determination of the sulfur and phosphorus distribution ratios, LS and LP, respectively, between molten iron and CaO-MgO(Saturated)-SiO2-Al 3O3-FeO slag was determined in the temperature range 1550-1650°C. Oxygen partial pressure was controlled by H2/H2O equilibrium in the range of 10-10-10-8 atm. For sulfur distribution, it was found that the trend of the distribution is the same as the previous work done under CO/CO2 atmosphere but LS in this case is 38-44 times less under similar oxygen partial pressure. This might be attributed to the impact of H2 on the distribution. Considering the fact that the input sulfur in the proposed process is approximately 34 times less than the blast furnace process, the proposed process would produce hot metal with approximately the same sulfur content to the hot metal produced by the blast furnace. For phosphorus distribution, LP was 450-1050 times that of the blast furnace. Also considering the amount of phosphorus input in the two processes, it was found that the expected P content in iron in the new process would be approximately three times less than in the blast furnace hot metal. This means that the proposed process will produce hot metal with much lower phosphorus which will minimize the need for dephosphorization in the steelmaking stage.

Mohassab Ahmed, Mohassab Yousef

112

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

113

The hopanoids of the purple non-sulfur bacteria Rhodopseudomonas palustris and Rhodopseudomonas acidophila and the absolute configuration of bacteriohopanetetrol.  

Science.gov (United States)

Five complex hopanoids have been detected in the purple non-sulfur bacterium Rhodopseudomonas acidophila. Next to the polyfunctionalized methylcyclopentane bacteriohopanetetrol ether already isolated from Methylobacterium organophilum, 35-carbamoylbacteriohopane-32,33,34-triol, 34,35-dicarbamoylbacteriohopane-32,33-diol and two nucleoside analogues, (22R)-30-(5'-adenosyl)hopane and (22S)-30-(5'-adenosyl)hopane were isolated and identified by spectroscopic and chemical methods. In Rhodopseudomonas palustris, however, only 35-amino-bacteriohopane-32,33,34-triol was detected. Chemical correlation between adenosylhopane and bacteriohopanetetrol, as well as comparison of derivatives obtained from bacterial and synthetic hopanoids, permitted the determination of the configurations of all asymmetric centres of the side-chain of bacteriohopanetetrol as 22R, 32R, 33R and 34S. According to the stereochemistry, this side-chain could be a D-ribose derivative linked through its C-5 carbon atom to the hopane skeleton. PMID:3338464

Neunlist, S; Bisseret, P; Rohmer, M

1988-01-15

114

Antimicrobial effects of green tea polyphenols on thermophilic spore-forming bacteria.  

Science.gov (United States)

The inhibitory action of tea polyphenols towards the development and growth of bacterial spores was examined. Among the tested Bacillus bacteria, tea polyphenols showed antibacterial effects towards Bacillus stearothermophilus, which is a thermophilic spore-forming bacterium. The heat resistance of B. stearothermophilus spores was reduced by the addition of tea polyphenols. Clostridium thermoaceticum, an anaerobic spore-forming bacterium, also exhibited reduced heat resistance of its spores in the presence of tea polyphenols. (-)-Epigallocatechin gallate, which is the main component of tea polyphenols, showed strong activity against both B. stearothermophilus and C. thermoaceticum. The heat resistance of these bacterial spores was more rapidly decreased by the addition of tea polyphenols at high temperatures. PMID:16232822

Sakanaka, S; Juneja, L R; Taniguchi, M

2000-01-01

115

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)

116

"Green preservatives": combating fungi in the food and feed industry by applying antifungal lactic acid bacteria.  

Science.gov (United States)

Fungal food spoilage plays a pivotal role in the deterioration of food and feed systems and some of them are also able to produce toxic compounds for humans and animals. The mycotoxins produced by fungi can cause serious health hazards, including cancerogenic, immunotoxic, teratogenic, neurotoxic, nephrotoxic and hepatotoxic effects, and Kashin-Beck disease. In addition to this, fungal spoilage/pathogens are causing losses of marketable quality and hygiene of foodstuffs, resulting in major economic problem throughout the world. Nowadays, food spoilage can be prevented using physical and chemical methods, but no efficient strategy has been proposed so far to reduce the microbial growth ensuring public health. Therefore, lactic acid bacteria (LAB) can play an important role as natural preservatives. The protection of food products using LAB is mainly due to the production of antifungal compounds such as carboxylic acids, fatty acids, ethanol, carbon dioxide, hydrogen peroxide, and bacteriocins. In addition to this, LAB can also positively contribute to the flavor, texture, and nutritional value of food products. This review mainly focuses on the use of LAB for food preservation given their extensive industrial application in a wide range of foods and feeds. The attention points out the several industrial patents concerning the use of antifungal LAB as biocontrol agent against spoilage organisms in different fermented foods and feeds. PMID:22909981

Pawlowska, Agata M; Zannini, Emanuele; Coffey, Aidan; Arendt, Elke K

2012-01-01

117

A DNA element recognised by the molybdenum-responsive transcription factor ModE is conserved in Proteobacteria, green sulphur bacteria and Archaea  

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Full Text Available Abstract Background The transition metal molybdenum is essential for life. Escherichia coli imports this metal into the cell in the form of molybdate ions, which are taken up via an ABC transport system. In E. coli and other Proteobacteria molybdenum metabolism and homeostasis are regulated by the molybdate-responsive transcription factor ModE. Results Orthologues of ModE are widespread amongst diverse prokaryotes, but not ubiquitous. We identified probable ModE-binding sites upstream of genes implicated in molybdenum metabolism in green sulphur bacteria and methanogenic Archaea as well as in Proteobacteria. We also present evidence of horizontal transfer of nitrogen fixation genes between green sulphur bacteria and methanogenic Archaea. Conclusions Whereas most of the archaeal helix-turn-helix-containing transcription factors belong to families that are Archaea-specific, ModE is unusual in that it is found in both Archaea and Bacteria. Moreover, its cognate upstream DNA recognition sequence is also conserved between Archaea and Bacteria, despite the fundamental differences in their core transcription machinery. ModE is the third example of a transcriptional regulator with a binding signal that is conserved in Bacteria and Archaea.

Pau Richard N

2003-12-01

118

A Green and Highly Efficient Solvent-free Synthesis of Novel Calicx[4]resorcinarene Derivatives Using Tungstate Sulfuric Acid  

International Nuclear Information System (INIS)

A facile and simple procedure for the synthesis of novel and known calix[4]resorcinarene derivatives were developed via a reaction of arylaldehydes with resorcinol in the presence of catalytic amounts of tungstate sulfuric acid (TSA) under solvent-free conditions. This eco-friendly method has many appealing attributes, such as excellent yields, short reactions times, use of safe and recoverable catalyst, and simple work-up procedures. TSA was characterized by powdered X-ray diffraction (XRD), X-ray fluorescence (XRF) and FTIR spectroscopy

119

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

120

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 lify 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)

 
 
 
 
121

The simultaneous presence of green rust 2 and sulfate reducing bacteria in the corrosion of steel sheet piles in a harbour area  

International Nuclear Information System (INIS)

Moessbauer spectroscopy and X-ray diffraction analysis allow to detect the presence of green rust 2, the ferrous-ferric sulfated compound of composition, 4Fe(OH)2, 2FeOOH, FeSO4, nH2O, mixed with magnetite at the surface of steel sheets corroded in a harbour area where the presence of sulfate reducing bacteria are also detected. (orig.)

122

The simultaneous presence of green rust 2 and sulfate reducing bacteria in the corrosion of steel sheet piles in a harbour area  

Science.gov (United States)

Mössbauer spectroscopy and X-ray diffraction analysis allow to detect the presence of green rust 2, the ferrous-ferric sulfated compound of composition, 4Fe(OH)2,2FeOOH,FeSO4,nH2O, mixed with magnetite at the surface of steel sheets corroded in a harbour area where the presence of sulfate reducing bacteria are also detected.

Génin, J.-M. R.; Olowe, A. A.; Benbouzid-Rollet, N. D.; Prieur, D.; Confente, M.; Resiak, B.

1992-04-01

123

Spectroscopic properties of a reconstituted light-harvesting complex from the green sulfur bacterium Chlorobium tepidum containing CsmA and bacteriochlorophyll a  

DEFF Research Database (Denmark)

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 . 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 R-helix. We have reconstituted the isolated CsmA protein with BChl a in micelles of n-octyl â-D-glucopyranoside. The resulting preparation reproduced the spectral characteristics of the CsmA-BChl a complex present in the chlorosome baseplate.

Pedersen, Marie Østergaard; Pham, Lan

2008-01-01

124

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

125

Benevolent behavior of Kleinia grandiflora leaf extract as a green corrosion inhibitor for mild steel in sulfuric acid solution  

Science.gov (United States)

The ethanolic extract of Kleinia grandiflora leaves was characterized and tested for its potential anticorrosion properties on mild steel in 1 M H2SO4 medium using mass-loss analysis, potentiodynamic polarization measurements, electrochemical impedance spectroscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy, UV-visible spectroscopy, and X-ray diffraction analysis. The effect of temperature on the corrosion behavior of mild steel was studied in the range of 308 to 328 K. The inhibition efficiency was observed to increase with increasing concentration of the extract. Polarization curves revealed that the Kleinia grandiflora leaf extract is a mixed inhibitor. Impedance diagrams revealed that an increase of Kleinia grandiflora leaf extract concentration increased the charge transfer resistance and decreased the double-layer capacitance. The adsorption process obeys Langmuir's model, with a standard free energy of adsorption (? G ads) of -18.62 kJ/mol. The obtained results indicate that the Kleinia grandiflora leaf extract can serve as an effective inhibitor for the corrosion of mild steel in a sulfuric acid medium.

Pitchaipillai, Muthukrishnan; Raj, Karthik; Balasubramanian, Jeyaprabha; Periakaruppan, Prakash

2014-11-01

126

Green Algae  

Science.gov (United States)

Color photomicrographs of several species of green algae with brief descriptions of their chief characteristics and habitat. Scroll to the bottom of the page to links to bacteria, and more protists including diatoms, desmids and rotifers.

Van Egmond, Wim

2010-01-01

127

Sulfur and Sulfuric Acid  

Science.gov (United States)

Sulfur is one of the few elements that is found in its elemental form in nature. Typical sulfur deposits occur in sedimentary limestone/gypsum formations, in limestone/anhydrite formations associated with salt domes, or in volcanic rock.1 A yellow solid at normal temperatures, sulfur becomes progressively lighter in color at lower temperatures and is almost white at the temperature of liquid air. It melts at 114-119°C (depending on crystalline form) to a transparent light yellow liquid as the temperature is increased. The low viscosity of the liquid begins to rise sharply above 160°C, peaking at 93 Pa·s at 188°C, and then falling as the temperature continues to rise to its boiling point of 445°C. This and other anomalous properties of the liquid state are due to equilibria between the various molecular species of sulfur, which includes small chains and rings.

D'Aquin, Gerard E.; Fell, Robert C.

128

Skin Bacteria Diversity and Spatial Distribution in Litoria genimaculata (GREEN- EYED TREE FROG Body Parts and its Bd-Inhibitory Activity -abstract-  

Directory of Open Access Journals (Sweden)

Full Text Available Several amphibian skin bacteria have shown inhibitory activity against the pathogenic fungus Batrachochytrium dendrobatidis (Bd. However‚ little is known about the spatial distribution of these inhibitory bacteria on amphibian skin‚ or their diversity. We looked at the diversity and distribution of skin bacteria of the green-eyed tree frog Litoria genimaculata. This stream-dwelling species from North Queensland rainforest declined in the early 1990s but has since recovered to pre-decline range population sizes. Swabs were taken from 5 body parts (hands‚ feet‚ legs and dorsal and ventral surfaces and inoculated onto agar plates for isolation of bacterial colonies. Bd- inhibitory activity was tested in challenge essays. Results show that feet had the highest number of bacterial isolates with Bd inhibitory activity followed by hands and legs with similar numbers of bacterial isolates and ventral body parts in that order. The dorsal surface had the lowest number of Bd inhibitory isolates. No sampled frogs were infected with Bd according to PCR assays‚ although Bd is endemic at the site. Information from morphological observations and Gram stains will be used to classify the bacterial isolates. Results will be analyzed for any patterns of distribution across the body of the frogs. Possible associations between body parts and bacterial isolates with and without Bd-inhibitory activity will be examined. This study will contribute to knowledge of the community structure of skin bacteria in frogs. Characterization of skin bacteria diversity is one of the first steps in understanding the role of amphibian skin bacteria in the resistance of the hosts to chytridiomycosis.

Martha L Silva-Velasco

2014-12-01

129

Microbiological analysis of the population of extremely haloalkaliphilic sulfur-oxidizing bacteria dominating in lab-scale sulfide-removing bioreactors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Thiopaq biotechnology for partial sulfide oxidation to elemental sulfur is an efficient way to remove H2S from biogases. However, its application for high-pressure natural gas desulfurization needs upgrading. Particularly, an increase in alkalinity of the scrubbing liquid is required. Therefore, the feasibility of sulfide oxidation into elemental sulfur under oxygen limitation was tested at extremely haloalkaline conditions in lab-scale bioreactors using mix sediments from hypersaline soda la...

Sorokin, D. Y.; Bosch, P. L. F.; Abbas, B.; Janssen, A. J. H.; Muyzer, G.

2008-01-01

130

Microbiological analysis of the population of extremely haloalkaliphilic sulfur-oxidizing bacteria dominating in lab-scale sulfide-removing bioreactors :  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Thiopaq biotechnology for partial sulfide oxidation to elemental sulfur is an efficient way to remove H2S from biogases. However, its application for high-pressure natural gas desulfurization needs upgrading. Particularly, an increase in alkalinity of the scrubbing liquid is required. Therefore, the feasibility of sulfide oxidation into elemental sulfur under oxygen limitation was tested at extremely haloalkaline conditions in lab-scale bioreactors using mix sediments from hypersaline soda la...

Sorokin, D. Y.; Den Bosch, P. L. F.; Abbas, B.; Janssen, A. J. H.; Muyzer, G.

2008-01-01

131

Green synthesis of protein capped silver nanoparticles from phytopathogenic fungus Macrophomina phaseolina (Tassi) Goid with antimicrobial properties against multidrug-resistant bacteria  

Science.gov (United States)

In recent years, green synthesis of nanoparticles, i.e., synthesizing nanoparticles using biological sources like bacteria, algae, fungus, or plant extracts have attracted much attention due to its environment-friendly and economic aspects. The present study demonstrates an eco-friendly and low-cost method of biosynthesis of silver nanoparticles using cell-free filtrate of phytopathogenic fungus Macrophomina phaseolina. UV-visible spectrum showed a peak at 450 nm corresponding to the plasmon absorbance of silver nanoparticles. Scanning electron microscopy (SEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM) revealed the presence of spherical silver nanoparticles of the size range 5 to 40 nm, most of these being 16 to 20 nm in diameter. X-ray diffraction (XRD) spectrum of the nanoparticles exhibited 2? values corresponding to silver nanoparticles. These nanoparticles were found to be naturally protein coated. SDS-PAGE analysis showed the presence of an 85-kDa protein band responsible for capping and stabilization of the silver nanoparticles. Antimicrobial activities of the silver nanoparticles against human as well as plant pathogenic multidrug-resistant bacteria were assayed. The particles showed inhibitory effect on the growth kinetics of human and plant bacteria. Furthermore, the genotoxic potential of the silver nanoparticles with increasing concentrations was evaluated by DNA fragmentation studies using plasmid DNA. PMID:25114655

2014-01-01

132

Analysis of iron- and sulfur-oxidizing bacteria in a treatment plant of acid rock drainage from a Japanese pyrite mine by use of ribulose-1, 5-bisphosphate carboxylase/oxygenase large-subunit gene.  

Science.gov (United States)

Iron- and sulfur-oxidizing bacteria in a treatment plant of acid rock drainage (ARD) from a pyrite mine in Yanahara, Okayama prefecture, Japan, were analyzed using the gene (cbbL) encoding the large subunit of ribulose-1, 5-bisphosphate carboxylase/oxygenase (RubisCO). Analyses of partial sequences of cbbL genes from Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans and Acidithiobacillus caldus strains revealed the diversity in their cbbL gene sequences. In contrast to the presence of two copies of form I cbbL genes (cbbL1 and cbbL2) in A. ferrooxidans genome, A. thiooxidans and A. caldus had a single copy of form I cbbL gene in their genomes. A phylogenetic analysis based on deduced amino acid sequences from cbbL genes detected in the ARD treatment plant and their close relatives revealed that 89% of the total clones were affiliated with A. ferrooxidans. Clones loosely affiliated with the cbbL from A. thiooxidans NB1-3 or Thiobacillus denitrificans was also detected in the treatment plant. cbbL gene sequences of iron- or sulfur-oxidizing bacteria isolated from the ARD and the ARD treatment plant were not detected in the cbbL libraries from the treatment plant, suggesting the low frequencies of isolates in the samples. PMID:20159572

Kamimura, Kazuo; Okabayashi, Ai; Kikumoto, Mei; Manchur, Mohammed Abul; Wakai, Satoshi; Kanao, Tadayoshi

2010-03-01

133

Phylogeny and distribution of the soxB gene among thiosulfate-oxidizing bacteria.  

Science.gov (United States)

A PCR protocol for the detection of sulfur-oxidizing bacteria based on soxB genes that are essential for thiosulfate oxidation by sulfur-oxidizing bacteria of various phylogenetic groups which use the 'Paracoccus sulfur oxidation' pathway was developed. Five degenerate primers were used to specifically amplify fragments of soxB genes from different sulfur-oxidizing bacteria previously shown to oxidize thiosulfate. The PCR yielded a soxB fragment of approximately 1000 bp from most of the bacteria. Amino acid and nucleotide sequences of soxB from reference strains as well as from new isolates and environmental DNA from a hydrothermal vent habitat in the North Fiji Basin were compared and used to infer relationships of soxB between sulfur-oxidizing bacteria belonging to various 16S rDNA-based phylogenetic groups. Major phylogenetic lines derived from 16S rDNA were confirmed by soxB phylogeny. Thiosulfate-oxidizing green sulfur bacteria formed a coherent group by their soxB sequences. Likewise, clearly separated branches demonstrated the distant relationship of representatives of alpha-, beta-, and gamma-Proteobacteria including representative species of the former genus Thiobacillus (now Halothiobacillus - gamma-Proteobacteria, Thiobacillus - beta-Proteobacteria and Starkeya - alpha-Proteobacteria). This general picture emerged although apparent evidence for lateral transfer of the soxB gene is indicated and comparison of soxB phylogeny and 16S rDNA phylogeny points to the significance of this gene transfer in hydrothermal vent bacterial communities of the North Fiji Basin. PMID:11313131

Petri, R; Podgorsek, L; Imhoff, J F

2001-04-13

134

Selective elimination of chloroplastidial DNA for metagenomics of bacteria associated with the green alga Caulerpa Taxifolia (bryopsidophyceae)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Molecular analyses of bacteria associated with photosynthetic organisms are often confounded by coamplification of the chloroplastidial 16S rDNA with the targeted bacterial 16S rDNA. This major problem has hampered progress in the characterization of bacterial communities associated to photosynthetic organisms and has limited the full realization of the potential offered by the last generation of metagenomics approaches. A simple and inexpensive method is presented, based on ethanol and bleac...

Aires, Tania; Marba, Nuria; Serrao, Ester A.; Duarte, Carlos M.; Arnaud-haond, Sophie

2012-01-01

135

The effect of Pediococcus acidilactici bacteria used as probiotic supplement on the growth and non-specific immune responses of green terror, Aequidens rivulatus.  

Science.gov (United States)

A 56-day feeding trial was conducted on a species of ornamental fish called green terror (Aequidens rivulatus) (0.388 ± 0.0021 g) to assess the effect of probiotic bacteria, Pediococcus acidilactici on the growth indices and innate immune response. The fish were randomly allocated into 9 oval tanks (120 l) at a density of 60 fish per tank. The experimental diets were comprised of the control (C), C complemented with fish oil (O) and the probiotic and fish oil (PA) and fed ad lib twice a day. The growth indices (specific growth rate (SGR), feed conversion ratio (FCR) and immunological indices of fish fed the diets including lysozyme activity, total immunoglobulin and alternative complement activity were measured. The Fish fed with the diet containing P. acidilactici (PA) displayed significantly (P < 0.05) higher final weight (3.25 ± 0.065 g), weight gain (830.94 ± 9.46%), SGR (3.53 ± 0.02%/day) and lower FCR (1.45 ± 0.011) compared to those of other experimental diets. Total immunoglobulin (10.05 ± 0.12 ?g/ml), lysozyme activity (4.08 ± 0.85 ?g/ml) and alternative complement activity (2.65 ± 0.12 U/ml) in the serum of PA fed fish showed significant compared to other treatments (P < 0.05). The results showed positive effects of P. acidilactici as a potent probiotic on growth indices and non-specific immune system of green terror. PMID:24161762

Neissi, Alireza; Rafiee, Gholamreza; Nematollahi, Mohammadali; Safari, Omid

2013-12-01

136

A green triple biocide cocktail consisting of a biocide, EDDS and methanol for the mitigation of planktonic and sessile sulfate-reducing bacteria.  

Science.gov (United States)

Sulfate-reducing bacteria (SRB) cause souring and their biofilms are often the culprit in Microbiologically Influenced Corrosion (MIC). The two most common green biocides for SRB treatment are tetrakis-hydroxymethylphosphonium sulfate (THPS) and glutaraldehyde. It is unlikely that there will be another equally effective green biocide in the market any time soon. This means more effective biocide treatment probably will rely on biocide cocktails. In this work a triple biocide cocktail consisting of glutaraldehyde or THPS, ethylenediaminedisuccinate (EDDS) and methanol was used to treat planktonic SRB and to remove established SRB biofilms. Desulfovibrio vulgaris (ATCC 7757), a corrosive SRB was used as an example in the tests. Laboratory results indicated that with the addition of 10-15% (v/v) methanol to the glutaraldehyde and EDDS double combination, mitigation of planktonic SRB growth in ATCC 1249 medium and a diluted medium turned from inhibition to a kill effect while the chelator dosage was cut from 2,000 to 1,000 ppm. Biofilm removal was achieved when 50 ppm glutaraldehyde combined with 15% methanol and 1,000 ppm EDDS was used. THPS showed similar effects when it was used to replace glutaraldehyde in the triple biocide cocktail to treat planktonic SRB. PMID:22806837

Wen, J; Xu, D; Gu, T; Raad, I

2012-02-01

137

Biological studies of hot springs. Algae and bacteria living in extreme environments; Onsen no seibutsugaku. Tokushu kankyo ni seisokusuru sorui to saikinrui  

Energy Technology Data Exchange (ETDEWEB)

This paper reviews studies on algae and bacteria living in extreme environments, such as hot springs. Most of algae living in extreme environments are blue-green algae. Species of algae living in hot springs reduce their kinds with increasing temperature, and reduce them drastically in the temperature range over 60 centigrade. Among algae living in hot springs, blue-green algae with acidophilic and thermophilic properties are elucidated. On the other hand, bacteria are classified into bacteria living in high temperature and strongly acidic environment, bacteria living in high temperature and nearly neutral environment, and bacteria living in relatively low temperature and strongly acidic environment. For the bacteria living in high temperature and strongly acidic environment, Bacillus genus bacteria and Archaebacteria are elucidated. For the bacteria living in high temperature and neutral environment, Bacillus genus bacteria, Thermus genus bacteria, Archaebacteria, and sulfur grass are elucidated. For the bacteria living in lower temperature and strongly acidic environment, Thiobacillus genus bacteria are elucidated. 174 refs., 11 figs., 5 tabs.

Sugimori, K. [Toho University, Tokyo (Japan). School of Medicine

1994-12-31

138

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.

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

2006-07-15

139

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

140

Sulfur revisited.  

Science.gov (United States)

Sulfur is a time-honored therapeutic agent useful in a variety of dermatologic disorders. Its keratolytic action is due to formation of hydrogen sulfide through a reaction that depends upon direct interaction between sulfur particles and keratinocytes. The smaller the particle size, the greater the degree of such interaction and the greater the therapeutic efficacy. When applied topically, sulfur induces various histologic changes, including hyperkeratosis, acanthosis, and dilatation of dermal vasculature. One study showed that sulfur was comedogenic when applied onto human and rabbit skin, findings that were not reproduced in other studies. About 1% of topically applied sulfur is systemically absorbed. Adverse effects from topically applied sulfur are uncommon and are mainly limited to the skin. In infants, however, fatal outcome after extensive application has been reported. PMID:2450900

Lin, A N; Reimer, R J; Carter, D M

1988-03-01

 
 
 
 
141

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

142

Self-aggregation behavior of synthetic zinc 3-hydroxymethyl-13/15-carbonyl-chlorins as models of main light-harvesting components in photosynthetic green bacteria.  

Science.gov (United States)

Zinc complexes of 3-hydroxymethyl-13/15-carbonyl-chlorins having a six-membered lactone as the E-ring were prepared by modifying purpurin-18 as models of bacteriochlorophyll-d, one of the chlorophyllous pigments in the main light-harvesting antenna systems (chlorosomes) of green photosynthetic bacteria. The synthetic 13-carbonylated compound self-aggregated in 1%(v/v) tetrahydrofuran and hexane to give large oligomers possessing red-shifted and broadened electronic absorption bands and intense circular dichroism bands at the shifted Q ( y ) region, indicating that the supramolecular structure of the resulting self-aggregate was similar to those of natural and artificial chlorosomal aggregates. The red-shift value observed here was smaller than the reported values in chlorosomal pigments having a five-membered keto-ring, which was ascribable to a weaker intermolecular hydrogen-bonding of 13-C=O with 3(1)-OH in a supramolecule of the former self-aggregate and suppression of the pi-pi interaction among the composite chlorins. On the other hand, the isomeric 15-carbonylated molecule was monomeric even in the nonpolar organic solvent, confirming the reported proposal that the linear orientation of three interactive moieties, OH, C=O and Zn, in a molecule is requisite for its chlorosomal self-aggregation. PMID:17912608

Tamiaki, Hitoshi; Yoshimura, Hideaki; Shimamura, Yasuhide; Kunieda, Michio

2008-01-01

143

Biological and Abiological Sulfur Reduction at High Temperatures †  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Reduction of elemental sulfur was studied in the presence and absencè of thermophilic sulfur-reducing bacteria, at temperatures ranging from 65 to 110°C, in anoxic artificial seawater media. Above 80°C, significant amounts of sulfide were produced abiologically at linear rates, presumably by the disproportionation of sulfur. These rates increased with increasing temperature and pH and were enhanced by yeast extract. In the same medium, the sulfur respiration of two recent thermophilic isol...

Belkin, Shimshon; Wirsen, Carl O.; Jannasch, Holger W.

1985-01-01

144

Bacteria: Fossil Record  

Science.gov (United States)

This description of the fossil record of bacteria focuses on one particular group of bacteria, the cyanobacteria or blue-green algae, which have left a fossil record that extends far back into the Precambrian. The oldest cyanobacteria-like fossils known are nearly 3.5 billion years old and are among the oldest fossils currently known. Cyanobacteria are larger than most bacteria and may secrete a thick cell wall. More importantly, cyanobacteria may form large layered structures, called stromatolites (if more or less dome-shaped) or oncolites (if round). The site also refers to pseudomorphs of pyrite and siderite, and a group of bacteria known as endolithic. Two links are available for more information. One provides information on the discovery of possible remains of bacteria-like organisms on a meteorite from Mars and the other has a research report on fossilized filamentous bacteria and other microbes, found in Cretaceous amber.

145

Sulfur Dioxide  

Science.gov (United States)

... other rulemaking documents. Policy and Guidance - Links to policies and guidance on SO 2 designations and implementation. Nonattainment Areas - Status of nonattainment areas (the Green Book) Air Quality Trends - Progress made in reducing SO 2 in ...

146

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

147

The Low-temperature Ion Sulfurizing Technology and its Applications  

Science.gov (United States)

A solid lubrication film mainly consists of FeS, which has excellent tribology properties, can be formed on the sulfurized iron or steel surface. The sulfurizing technology has aroused intense attention from the day it appeared. However, the widespread industrial application of sulfurizing technology was promoted by the low-temperature ion sulfurizing (LTIS) process. This paper summarized the phylogeny and sorts of sulfurizing technology firstly; then, the process flow of LTIS technology, the forming mechanism, microstructure and tribological properties of ion sulfurized layer were introduced detailedly; and then, the technological, economic and environmental merits of LTIS technology were generalized; finally, the industrial applications of LTIS technology in various typical rolling, sliding and heavy duty parts were reviewed briefly. LTIS technology, with the advantages of high sulfurizing speed, good performance of sulfurized layer and without sideeffect, has played an important role in the tribology modification of ferrous parts, and the LTIS process will become more green, simple and efficient in the future.

Ma, G. Z.; Xu, B. S.; Wang, H. D.; Li, G. L.; Zhang, S.

148

Oxidation of inorganic sulfur compounds in acidophilic prokaryotes  

Energy Technology Data Exchange (ETDEWEB)

The oxidation of reduced inorganic sulfur compounds to sulfuric acid is of great importance for biohydrometallurgical technologies as well as the formation of acidic (below pH 3) and often heavy metal-contaminated environments. The use of elemental sulfur as an electron donor is the predominant energy-yielding process in acidic natural sulfur-rich biotopes but also at mining sites containing sulfidic ores. Contrary to its significant role in the global sulfur cycle and its biotechnological importance, the microbial fundamentals of acidophilic sulfur oxidation are only incompletely understood. Besides giving an overview of sulfur-oxidizing acidophiles, this review describes the so far known enzymatic reactions related to elemental sulfur oxidation in acidophilic bacteria and archaea. Although generally similar reactions are employed in both prokaryotic groups, the stoichiometry of the key enzymes is different. Bacteria oxidize elemental sulfur by a sulfur dioxygenase to sulfite whereas in archaea, a sulfur oxygenase reductase is used forming equal amounts of sulfide and sulfite. In both cases, the activation mechanism of elemental sulfur is not known but highly reactive linear sulfur forms are assumed to be the actual substrate. Inhibition as well as promotion of these biochemical steps is highly relevant in bioleaching operations. An efficient oxidation can prevent the formation of passivating sulfur layers. In other cases, a specific inhibition of sulfur biooxidation may be beneficial for reducing cooling and neutralization costs. In conclusion, the demand for a better knowledge of the biochemistry of sulfur-oxidizing acidophiles is underlined. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

Rohwerder, T.; Sand, W. [Universitaet Duisburg-Essen, Biofilm Centre, Aquatic Biotechnology, Duisburg (Germany)

2007-07-15

149

BOGUS BACTERIA...  

Science.gov (United States)

Here are some websites to get you started... Just click on the links and start searching! microbe world- bacteria Bacteria Rule Quiz! Bacteria.... Harmful Bacteria Bacteria Museum Bacteria! Microbes- all sorts of info... When you are finished looking at the sites or when you have enough information concerning bacteria, ask Mrs. Deaton for some books that can give you even more DETAIL!!! *Don\\'t forget to keep track of your information on your I-CHARTS... ...

Deaton, Mrs.

2007-01-24

150

Effect of acidic pH on flow cytometric detection of bacteria stained with SYBR Green I and their distinction from background  

Science.gov (United States)

Unspecific background caused by biotic or abiotic particles, cellular debris, or autofluorescence is a well-known interfering parameter when applying flow cytometry to the detection of microorganisms in combination with fluorescent dyes. We present here an attempt to suppress the background signal intensity and thus to improve the detection of microorganisms using the nucleic acid stain SYBR® Green I. It has been observed that the fluorescent signals from SYBR Green I are greatly reduced at acidic pH. When lowering the pH of pre-stained samples directly prior to flow cytometric analysis, we hypothesized that the signals from particles and cells with membrane damage might therefore be reduced. Signals from intact cells, temporarily maintaining a neutral cytosolic pH, should not be affected. We show here that this principle holds true for lowering background interference, whereas the signals of membrane-compromised dead cells are only affected weakly. Signals from intact live cells at low pH were mostly comparable to signals without acidification. Although this study was solely performed with SYBR® Green I, the principle of low pH flow cytometry (low pH-FCM) might hold promise when analyzing complex matrices with an abundance of non-cellular matter, especially when expanded to non-DNA binding dyes with a stronger pH dependence of fluorescence than SYBR Green I and a higher pKa value.

Baldock, Daniel; Nebe-von-Caron, Gerhard; Bongaerts, Roy; Nocker, Andreas

2013-12-01

151

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

152

Sulfur isotope fractionation during the reduction of elemental sulfur and thiosulfate by Dethiosulfovibrio spp.  

Science.gov (United States)

Thiosulfate and elemental sulfur are typical by-products of the oxidation of dissolved sulfide and important sulfur intermediates in the biogeochemical sulfur cycle of natural sediments where they can be further transformed by microbial or chemical oxidation, reduction, or disproportionation. Due to the often superimposing reaction pathways of the sulfur intermediates in natural environments specific tracers are needed to better resolve the complex microbial and biogeochemical reactions. An important fingerprint for sulfur cycling is provided by the microbial fractionation of the stable sulfur isotopes S-34 and S-32. Proper interpretation of isotope signals in nature, however, is only possible by the calibration with results obtained with pure cultures under defined experimental conditions. In addition, sulfur isotope discrimination may provide informations about specific encymatic biochemical pathways within the bacterial cells. In this study, we report the results for the discrimination of stable sulfur isotopes S-32 and S-34 during reduction of thiosulfate and elemental sulfur by non-sulfate, but sulfur- and thiosulfate-reducing bacteria which are phylogenetically not related to sulfate-reducing bacteria. Experiments with were conducted at known cell-specific thiosulfate reduction rates. Stable sulfur isotope fractionation was investigated during reduction of thiosulfate and elemental sulfur at 28°C by growing batch cultures of Dethiosulfovibrio marinus WS100 (type strain DSM 12537) and Dethiosulfovibrio russensis (type strain DSM 12538) using citrate as carbon and energy source. The cell-specific reduction rates were 0.3 to 2.4 fmol cell-1 d-1 (thiosulfate) and 31 to 38 fmol cell-1 d-1 (elemental sulphur), respectively. The sulfide produced was depleted in S-34 by 12 per mil compared to total thiosulfate sulfur, close to previous results observed for sulfate-reducing bacteria, indicating that the thiosulfate-reducing mechanism of sulfate reducers is similar to that of the investigated thiosulfate-reducing strains. Elemental sulfur reduction yields sulfide depleted in S-34 and isotope fractionation effects between 1.3 and 5.2 per mil for Dethiosulfovibrio russensis and 1.7 and 5.1 per mil Dethiosulfovibrio marinus, with the smaller fractionation effects observed in the exponential growth phase and enhanced discrimination under conditions of citrate depletion and cell lysis.

Surkov, A. V.; Böttcher, M. E.; Kuever, J.

2009-04-01

153

Anaerobic bacteria  

Science.gov (United States)

Anaerobic bacteria are bacteria that do not live or grow in the presence of oxygen. In humans, ... Goldstein EJ. Diseases caused by non-spore forming anaerobic bacteria. In: Goldman L, Schafer AI, eds. Goldman's ...

154

Ferrihydrite-dependent growth of Sulfurospirillum deleyianum through electron transfer via sulfur cycling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Observations in enrichment cultures of ferric iron-reducing bacteria indicated that ferrihydrite was reduced to ferrous iron minerals via sulfur cycling with sulfide as the reductant. Ferric iron reduction via sulfur cycling was investigated in more detail with Sulfurospirillum deleyianum, which can utilize sulfur or thiosulfate as an electron acceptor. In the presence of cysteine (0.5 or 2 mM) as the sole sulfur source, no (microbial) reduction of ferrihydrite or ferric citrate was observed,...

Straub, Kristina Lotte; Schink, Bernhard

2004-01-01

155

High-sulfur in beef cattle diets: a review.  

Science.gov (United States)

While many cattle feeding areas in the United States have long dealt with high sulfate water, increased feeding of ethanol coproducts such as distillers grains with solubles to beef cattle has led to a corresponding increase in dietary sulfur. As a result, sulfur metabolism in the ruminant has been the focus of many research studies over the past 10 yr, and advances in our knowledge have been made. Excessive sulfur in cattle diets may have implications on trace mineral absorption, dry matter intake, and overall cattle growth. This review will focus on what we have learned about the metabolism of sulfur in the ruminant, including ruminal sulfate reducing bacteria, the role of ruminally available sulfur, factors affecting the production of hydrogen sulfide in the rumen, and the potential mechanisms behind sulfur toxicity in cattle. Additionally, this review will discuss potential strategies to minimize risk of sulfur toxicity when cattle are fed high-sulfur diets, including dietary and management strategies. Further research related to high-sulfur diets including implications for carcass characteristics, meat quality, and animal health will also be discussed. As ethanol production processes continue to change, the nutrient profile of the resulting coproducts will as well. Often removal of one nutrient such as oil will result in the concentration of other nutrients such as sulfur. Therefore, it seems even more likely that a better understanding of sulfur metabolism in the ruminant will be important to beef cattle feeding in the future. PMID:24981568

Drewnoski, M E; Pogge, D J; Hansen, S L

2014-09-01

156

Bacteria Museum  

Science.gov (United States)

Who knew that bacteria had their own virtual museum? Here, visitors will "learn that not all bacteria are harmful, how they are used in industry, that they belong to the oldest living creatures on Earth", and many more interesting facts to discover about the diverse world of bacteria. The "Bacterial Species Files" tab at the top of the page, allows visitors to look up information on 40 different specific bacteria, from Anthrax to Yersinia enterocolitica. The information provided for each bacterium includes photographs, consumer guides, fact sheets, and scientific links. Visitors will find that the "Main Exhibits" tab addresses the basics about bacteria, as well as "Pathogenic Bacteria", "Evolution", "How We Fight Bacteria", and "Food and Water Safety". Visitors will surely enjoy the "Good Bacteria in Food" link found in the Food and Water Safety section, as it explains how some foods benefit from good bacteria, such as Swiss cheese, sausage, sauerkraut, chocolate, and coffee.

157

Microbial stabilization of sulfur-landen sorbents; Technical report, September 1--November 30, 1993  

Energy Technology Data Exchange (ETDEWEB)

Clean coal technologies that involve limestone for sulfur capture generate lime/limestone products laden with sulfur at various oxidation states. If sulfur is completely stabilized as sulfate, the spent sorbent is ready for commercial utilization as gypsum. However, the presence of reduced sulfur species requires additional processing. Thermal oxidation of reduced sulfur can result in undesirable release of SO{sub 2}. Microbial oxidation might provide an inexpensive and effective alternative. Sorbents laden with reduced forms of sulfur such as sulfide, sulfite, or various polythionate species serve as growth substrates for sulfur-oxidizing bacteria, which have the potential to convert all sulfur to sulfate. This quarter, efforts focused on determining the combined effects of dibasic acids (DBA) and Ca{sup +2} concentration on several strains of neutrophilic thiobacilli, including Thiobacillus neapolitanus ATCC 23639 and ATCC 23641, and an isolate, TQ1, which was obtained from a commercial sulfur dioxide scrubber that utilizes DBA.

Miller, K.W. [Illinois State Univ., Normal, IL (United States)

1993-12-31

158

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

159

Sulfur tolerant anode materials  

Energy Technology Data Exchange (ETDEWEB)

The goal of this program is the development of a molten carbonate fuel cell (MCFC) anode which is more tolerant of sulfur contaminants in the fuel than the current state-of-the-art nickel-based anode structures. This program addresses two different but related aspects of the sulfur contamination problem. The primary aspect is concerned with the development of a sulfur tolerant electrocatalyst for the fuel oxidation reaction. A secondary issue is the development of a sulfur tolerant water-gas-shift reaction catalyst and an investigation of potential steam reforming catalysts which also have some sulfur tolerant capabilities. These two aspects are being addressed as two separate tasks.

1988-02-01

160

Growth kinetics of hydrogen sulfide oxidizing bacteria in corroded concrete from sewers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Hydrogen sulfide oxidation by microbes present on concrete surfaces of sewer pipes is a key process in sewer corrosion. The growth of aerobic sulfur oxidizing bacteria from corroded concrete surfaces was studied in a batch reactor. Samples of corrosion products, containing sulfur oxidizing bacteria, were suspended in aqueous solution at pH similar to that of corroded concrete. Hydrogen sulfide was supplied to the reactor to provide the source of reduced sulfur. The removal of hydrogen sulfide...

Jensen, H. S.; Lens, P. N. L.; Nielsen, J. L.; Bester, K.; Nielsen, A. H.; Hvitved-jacobsen, Th; Vollertsen, J.

2011-01-01

 
 
 
 
161

Effect of different types of elemental sulfur on bioleaching of heavy metals from contaminated sediments.  

Science.gov (United States)

The application of two different types of elemental sulfur (S0) was studied to evaluate the efficiency on bioleaching of heavy metals from contaminated sediments. Bioleaching tests were performed in suspension and in the solid-bed with a heavy metal contaminated sediment using commercial sulfur powder (technical sulfur) or a microbially produced sulfur waste (biological sulfur) as substrate for the indigenous sulfur-oxidizing bacteria and thus as acid source. Generally, using biological sulfur during suspension leaching yielded in considerably better results than technical sulfur. The equilibrium in acidification, sulfur oxidation and metal solubilization was reached already after 10-14 d of leaching depending upon the amount of sulfur added. The metal removal after 28 d of leaching was higher when biological sulfur was used. The biological sulfur added was oxidized with high rate, and no residual S0 was detectable in the sediment samples after leaching. The observed effects are attributable to the hydrophilic properties of the biologically produced sulfur particles resulting in an increased bioavailability for the Acidithiobacilli. In column experiments only poor effects on the kinetics of the leaching parameters were observed replacing technical sulfur by biological sulfur, and the overall metal removal was almost the same for both types of S0. Therefore, under the conditions of solid-bed leaching the rate of sulfur oxidation and metal solubilization is more strongly affected by transport phenomena than by microbial conversion processes attributed to different physicochemical properties of the sulfur sources. The results indicate that the application of biological sulfur provides a suitable means for improving the efficiency of suspension leaching treatments by shortening the leaching time. Solid-bed leaching treatments may benefit from the reuse of biological sulfur by reducing the costs for material and operating. PMID:16054192

Seidel, Heinz; Wennrich, Rainer; Hoffmann, Petra; Löser, Christian

2006-03-01

162

Assimilatory sulfur metabolism in marine microorganisms: characteristics and regulation of sulfate transport in Pseudomonas halodurans and Alteromonas luteo-violaceus.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Sulfate transport capacity was not regulated by cysteine, methionine, or glutathione in Pseudomonas halodurans, but growth on sulfate or thiosulfate suppressed transport. Subsequent sulfur starvation of cultures grown on all sulfur sources except glutathione stimulated uptake. Only methionine failed to regulate sulfate transport in Alteromonas luteo-violaceus, and sulfur starvation of all cultures enhanced transport capacity. During sulfur starvation of sulfate-grown cultures of both bacteria...

Cuhel, R. L.; Taylor, C. D.; Jannasch, H. W.

1981-01-01

163

Bacteria Transformation  

Science.gov (United States)

Students construct paper recombinant plasmids to simulate the methods genetic engineers use to create modified bacteria. They learn what role enzymes, DNA and genes play in the modification of organisms. For the particular model they work on, they isolate a mammal insulin gene and combine it with a bacteria's gene sequence (plasmid DNA) for production of the protein insulin.

National Science Foundation GK-12 and Research Experience for Teachers (RET) Programs,

164

GEOCHEMISTRY OF SULFUR IN IRON CORROSION SCALES FOUND IN DRINKING WATER DISTRIBUTION SYSTEMS  

Science.gov (United States)

Iron-sulfur geochemistry is important in many natural and engineered environments, including drinking water systems. In the anaerobic environment beneath scales of corroding iron drinking water distribution system pipes, sulfate reducing bacteria (SRB) produce sulfide from natu...

165

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

166

Genetic transfer in acidophilic bacteria  

Energy Technology Data Exchange (ETDEWEB)

There is increasing interest in the use of microorganisms to recover metals from ores, as well as to remove sulfur from coal. These so-called bioleaching processes are mediated by a number of bacteria. The best-studied of these organisms are acidophiles including Thiobacillus and Acidiphilium species. Our laboratory has focused on developing genetic strategies to allow the manipulation of acidophilic bacteria to improve and augment their utility in large scale operations. We have recently been successful in employing conjugation for interbacterial transfer of genetic information, as well as in directly transforming Acidiphilium by use of electroporation. We are now testing the properties of IncPl, IncW and IncQ plasmid vectors in Acidiphilium to determine their relative usefulness in routine manipulation of acidophiles and transfer between organisms. This study also allows us to determine the natural ability of these bacteria to transfer genetic material amongst themselves in their particular environment. 21 refs., 3 figs., 2 tabs.

Roberto, F.F.; Glenn, A.W.; Bulmer, D.; Ward, T.E.

1990-01-01

167

Advanced sulfur control concepts  

Energy Technology Data Exchange (ETDEWEB)

Regenerable metal oxide sorbents, such as zinc titanate, are being developed to efficiently remove hydrogen sulfide (H{sub 2}S) from coal gas in advanced power systems. Dilute air regeneration of the sorbents produces a tailgas containing a few percent sulfur dioxide (SO{sub 2}). Catalytic reduction of the SO{sub 2} to elemental sulfur with a coal gas slipstream using the Direct Sulfur Recovery Process (DSRP) is a leading first-generation technology. Currently the DSRP is undergoing field testing at gasifier sites. The objective of this study is to develop second-generation processes that produce elemental sulfur without coal gas or with limited use. Novel approaches that were evaluated to produce elemental sulfur from sulfided sorbents include (1) sulfur dioxide (SO{sub 2}) regeneration, (2) substoichiometric (partial) oxidation, (3) steam regeneration followed by H{sub 2}S oxidation, and (4) steam-air regeneration. Preliminary assessment of these approaches indicated that developing SO{sub 2} regeneration faced the fewest technical and economic problems among the four process options. Elemental sulfur is the only likely product of SO{sub 2} regeneration and the SO{sub 2} required for the regeneration can be obtained by burning a portion of the sulfur produced. Experimental efforts have thus been concentrated on SO{sub 2}-based regeneration processes. Results from laboratory investigations are presented and discussed.

Gangwal, S.K.; Turk, B.S.; Gupta, R.P.

1995-11-01

168

Elemental sulfur recovery process  

Science.gov (United States)

An improved catalytic reduction process for the direct recovery of elemental sulfur from various SO.sub.2 -containing industrial gas streams. The catalytic process provides combined high activity and selectivity for the reduction of SO.sub.2 to elemental sulfur product with carbon monoxide or other reducing gases. The reaction of sulfur dioxide and reducing gas takes place over certain catalyst formulations based on cerium oxide. The process is a single-stage, catalytic sulfur recovery process in conjunction with regenerators, such as those used in dry, regenerative flue gas desulfurization or other processes, involving direct reduction of the SO.sub.2 in the regenerator off gas stream to elemental sulfur in the presence of a catalyst.

Flytzani-Stephanopoulos, Maria (Winchester, MA); Hu, Zhicheng (Somerville, MA)

1993-01-01

169

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

170

Metaphysical green  

DEFF Research Database (Denmark)

“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 nature” The notion of Sensation of Green was developed through a previous study ‘Learning from the Summer House’ 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 – 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 ‘House before House’ , in Tokyo. The third example is a prefabricated house ‘CHU’ . The analysis evaluates the characteristics of diverse tones of green – 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

171

A phylogenetic survey of budding, and/or prosthecate, non-phototrophic eubacteria: membership of Hyphomicrobium, Hyphomonas, Pedomicrobium, Filomicrobium, Caulobacter and "dichotomicrobium" to the alpha-subdivision of purple non-sulfur bacteria.  

Science.gov (United States)

The phylogenetic position of various budding and/or or prosthecate Gram-negative eubacteria was determined by different methods. Members of the genera Hyphomicrobium, Filomicrobium, Pedomicrobium were investigated by 16S rRNA cataloguing, a 1373 nucleotide long portion of the 16S rRNA was sequenced from Hyphomicrobium vulgare and the 5S rRNAs were analyzed from two Hyphomicrobium strains, Hyphomonas polymorpha and Caulobacter crescentus. Comparison with published sequences indicated a membership of all of these organisms to the alpha subdivision of purple bacteria. While C. crescentus and Hyphomonas polymorpha constitute separate individual lines of descent, the position of a coherent cluster embracing Hyphomicrobium, Pedomicrobium and Filomicrobium is not yet settled. 16S rRNA cataloguing indicate the presence of a distinct line equivalent to other subgroups in its phylogenetic depth. 5S rRNA analysis, on the other hand, groups Hyphomicrobium vulgare and strain IFAM 1761 with members of subgroup alpha-2 (Rhodopseudomonas palustris, Nitrobacter winogradskyi and relatives). In contrast to the present classification, Pedomicrobium ferrugineum and Filimicrobium fusiforme are more closely related to certain Hyphomicrobium strains than these are related among each other. Budding mode of reproduction and prosthecate morphology are dominating morphological features of members of the alpha subdivision. These characteristics may gain diagnostic significance in a future formal description of this subdivision and its subgroups as a higher rank. PMID:2455491

Stackebrandt, E; Fischer, A; Roggentin, T; Wehmeyer, U; Bomar, D; Smida, J

1988-01-01

172

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

173

Town Greens  

Science.gov (United States)

This lovely website notes that the town greens of Connecticut embody the Nutmeg State's "strong self sense of history and civic pride." Created by the Connecticut Trust for Historic Preservation, this site brings together essays, photographs, and other materials that tell the story of some of the state's most well-known town greens. First-time visitors can use the Green Link area to learn more about any of the state's 172 greens. Visitors will see the profile of each green includes a narrative essay that describes the green's landscape, its history, and prominent nearby buildings and public monuments. The Exhibits area includes in-depth looks at town greens in Guilford, New Haven, Norwich, and more. The site also includes a Data Center section. Users will find detailed information on most of the town greens in the state, along with additional data resources such as planning documents.

2001-01-01

174

Technetium-sulfur colloid  

International Nuclear Information System (INIS)

The chemistry of the technetium-sulfur colloid produced by the reaction of sodium thiosulfate with acid was investigated. A commercial kit was duplicated, and analyses of elemental sulfur, bisulfite and residual thiosulfate were carried out. The colloidal dispersions were filtered through Nuclepore graded membranes, and the percentages of sulfur and of sup(99m)Tc in the various filtrates were determined. In all cases - with varying acid, thiosulfate and time of incubation - there was a rough agreement between the two percentages for particles 0.4?m in diameter or more. However, for small particles (1S3O6, used in place of sodium thiosulfate, produced small Tc-S colloid particles with less sulfur than the conventional thiosulfate-acid system. (author)or)

175

Sulfur spring dermatitis.  

Science.gov (United States)

Thermal sulfur baths are a form of balneotherapy promoted in many cultures for improvement of skin conditions; however, certain uncommon skin problems may occur after bathing in hot sulfur springs. We report the case of a 65-year-old man who presented with multiple confluent, punched-out, round ulcers with peripheral erythema on the thighs and shins after bathing in a hot sulfur spring. Histopathologic examination revealed homogeneous coagulation necrosis of the epidermis and papillary dermis. Tissue cultures showed no evidence of a microbial infection. The histopathologic findings and clinical course were consistent with a superficial second-degree burn. When patients present with these findings, sulfur spring dermatitis should be considered in the differential diagnosis. Moreover, the patient's clinical history is crucial for correct diagnosis. PMID:25474449

Lee, Chieh-Chi; Wu, Yu-Hung

2014-11-01

176

Sulfur and climate changes  

International Nuclear Information System (INIS)

The sulfur released by some industries and by the phytoplankton acts on the environment: it cools the earth while forming tiny particles which spread the solar light and send it back towards space. The resulting cooling compensates partly the global warming due to greenhouse effect. The sulfur compounds are also liable for the acid rains, the mist formation and the rarefaction of atmospheric ozone. 3 refs., 4 figs

177

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

178

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 hybrid type II/III ribulose-1,5-bisphosphate carboxylase-oxygenase (RuBisCO) that couples adenosine monophosphate salvage with CO2 fixation, a pathway not previously 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. [University of California, Berkeley; Thomas, BC [University of California, Berkeley; Sharon, I [University of California, Berkeley; Miller, CS [University of California, Berkeley; Castelle, Cindy J [Lawrence Berkeley National Laboratory (LBNL); Verberkmoes, Nathan C [ORNL; Wilkins, Michael J. [Pacific Northwest National Laboratory (PNNL); Hettich, Robert {Bob} L [ORNL; Lipton, Mary S [Pacific Northwest National Laboratory (PNNL); Williams, Ken [Lawrence Berkeley National Laboratory (LBNL); Long, Philip E [Lawrence Berkeley National Laboratory (LBNL); Banfield, Jillian F. [University of California, Berkeley

2012-01-01

179

Dense populations of a giant sulfur bacterium in Namibian shelf sediments  

DEFF Research Database (Denmark)

A previously unknown giant sulfur bacterium is abundant in sediments underlying the oxygen minimum zone of the Benguela Current upwelling system. The bacterium has a spherical cell that exceeds by up to 100-fold the biovolume of the largest known prokaryotes. On the basis of 16S ribosomal DNA sequence data, these bacteria are closely related to the marine filamentous sulfur bacteria Thioploca, abundant in the upwelling area off Chile and Peru. Similar to Thioploca, the giant bacteria oxidize sulfide with nitrate that is accumulated to less than or equal to 800 millimolar in a central vacuole.

Schulz, HN; Brinkhoff, T.

1999-01-01

180

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

 
 
 
 
181

Sulfur Substitution in Oxyanions.  

Science.gov (United States)

Sulfide can react with oxyanions in two ways. In anions such as chromate, iodate or permanganate, the central metal(loid) is reduced rapidly. In anions such as molybdate, arsenate or antimonate, sulfur atoms substitute for oxygen atoms in the first coordination sphere. In the latter cases, the central metal(loid) often retains its high oxidation state in the final thioanion; however lower valent species, which tend to be coordinatively more labile, may be important reaction intermediates. Replacement of oxygen by sulfur "softens" oxyanions, in some cases making them strong binders of soft metals, like Cu, Ag, Au and Hg. These changes also can profoundly affect the geochemical fate of the metal(loids). Sulfur substitution in oxyanions can be extremely sluggish. Recently, computational chemistry has begun to yield information about sulfur substitution reactions that are too slow to be studied experimentally but yet are potentially important in geochemistry. Thioperrhenates, thiovanadates and thiotungstates are species whose geochemical roles, if any, remain to be determined. It is possible that sulfur substitution reactions are more important under hydrothermal conditions than at ambient temperatures. For example, germanate dominates the ambient-temperature chemistry of Ge, but in hydrothermal deposits this element occurs commonly in sulfide minerals.

Helz, G. R.

2008-12-01

182

Natural sulfur dioxide emissions from sulfuric soils  

Science.gov (United States)

Soils have long been recognised as sulfur dioxide (SO 2) sinks, but we show that they can also be sources of atmospheric SO 2. Using static chambers and micrometeorological techniques, we have measured emissions of SO 2 from coastal lowland soils containing sulfides (mostly pyrite), commonly referred to as acid sulfate soils in Australia. SO 2 evolution seems coupled to evaporation of soil water containing sulfite. The global emissions of S from acid sulfate soils is estimated at about 3 Tg/year, which is of the same order as emissions from terrestrial biogenic sources and biomass burning and is about 3% of known anthropogenic emissions of S.

Macdonald, Bennett C. T.; Denmead, O. Tom; White, Ian; Melville, Michael D.

183

Sulfur activation in Hiroshima  

International Nuclear Information System (INIS)

In 1979, we attempted to establish the validity of source terms for the Hiroshima and Nagasaki bombs using experimental data on sulfur activation. Close agreement was observed between measured and calculated values for test firings of Nagasaki-type bombs. The calculated values were based on source terms developed by W.E. Preeg at the Los Alamos National Laboratory (LANL). A discrepancy was found, however, when we compared calculated values for the two bombs because a 1956 report by R.R. Wilson stated that sulfur acitvation by fast neutrons in Hiroshima was approximately three times greater than in Nagasaki. Our calculations based on Preeg's source-term data predicted about equal sulfur activation in the two cities

184

Advanced sulfur control concepts  

Energy Technology Data Exchange (ETDEWEB)

The primary objective of this study is the direct production of elemental sulfur during the regeneration of high temperature desulfurization sorbents. Three possible regeneration concepts were identified as a result of a literature search. The potential for elemental sulfur production from a number of candidate metal oxide sorbents using each regeneration concept was evaluated on the basis of a thermodynamic analysis. Two candidate sorbents, Fe{sub 2}O{sub 3} and CeO{sub 2} were chosen for experimental testing. The experimental test program using both electrobalance and fixed-bed reactor sis now getting underway. The objective is to determine reaction conditions--temperature, pressure, space velocity, and regeneration feed gas composition--which will maximize the yield of elemental sulfur in the regeneration product gas. Experimental results are to be used to define a conceptual desulfurization-regeneration process and to provide a preliminary economic evaluation.

Harrison, D.P.; Lopez-Ortiz, A.; White, J.D.; Groves, F.R. Jr.

1995-11-01

185

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

186

Sodium sulfur battery seal  

Science.gov (United States)

This disclosure is directed to an improvement in a sodium sulfur battery construction in which a seal between various battery compartments is made by a structure in which a soft metal seal member is held in a sealing position by holding structure. A pressure applying structure is used to apply pressure on the soft metal seal member when it is being held in sealing relationship to a surface of a container member of the sodium sulfur battery by the holding structure. The improvement comprises including a thin, well-adhered, soft metal layer on the surface of the container member of the sodium sulfur battery to which the soft metal seal member is to be bonded.

Mikkor, Mati (Ann Arbor, MI)

1981-01-01

187

Sodium sulfur battery seal  

Energy Technology Data Exchange (ETDEWEB)

This disclosure is directed to an improvement in a sodium sulfur battery construction in which a seal between various battery compartments is made by a structure in which a soft metal seal member is held in a sealing position by holding structure. A pressure applying structure is used to apply pressure on the soft metal seal member when it is being held in sealing relationship to a surface of a container member of the sodium sulfur battery by the holding structure. The improvement comprises including a thin, well-adhered, soft metal layer on the surface of the container member of the sodium sulfur battery to which the soft metal seal member is to be bonded.

Mikkor, M.

1981-01-13

188

Volume efficient sodium sulfur battery  

Energy Technology Data Exchange (ETDEWEB)

A sodium sulfur battery is described. A plurality of box shaped sulfur electrodes are provided, the outer surfaces of which are defined by an electrolyte material. Each of the electrodes have length and width dimensions substantially greater than the thicknesses thereof as well as upwardly facing surface and a downwardly facing surface. An electrode structure is contained in each of the sulfur electrodes. A holding structure is provided for holding the plurality of sulfur electrodes in a stacked condition with the upwardly facing surface of one sulfur electrode in facing relationship to the downwardly facing surface of another sulfur electrode thereabove. A small thickness dimension separates each of the stacked electrodes thereby defining between each pair of sulfur electrodes a volume which receives the sodium reactant. A reservoir is provided for containing sodium. A manifold structure interconnects the volumes between the sulfur electrodes and the reservoir. A metering structure controls the flow of sodium between the reservoir and the manifold structure.

Mikkor, M.

1980-10-07

189

The role of "blebbing" in overcoming the hydrophobic barrier during biooxidation of elemental sulfur by Thiobacillus thiooxidans  

Science.gov (United States)

Brimstone Basin, in southeastern Yellowstone National Park, Wyoming is an ancient hydrothermal area containing solfataric alteration. Drainage waters flowing from Brimstone Basin had pH values as low as 1.23 and contained up to 1.7×106 MPN/ml acidophilic sulfur-oxidizing bacteria. Thiobacillus thiooxidans was the dominant sulfur-oxidizing bacterium recovered from an enrichment culture and was used in a structural examination of bacterial sulfur oxidation. Growth in these sulfur cultures occurred in two phases with cells in association with the macroscopic sulfur grains and in suspension above these grains. Colonization of sulfur grains by individual cells and microcolonies was facilitated by organic material that appeared to be responsible for bacterial adhesion. Transmission electron microscopy of negatively stained (2% [wt./vol.] uranyl acetate), sulfur-grown T. thiooxidans revealed extensive membrane blebbing (sloughing of outer membrane vesicles) and the presence of approximately 100 nm sized sulfur particles adsorbed to membrane material surrounding individual bacteria. Sulfite-grown bacteria did not possess membrane blebs. The amphipathic nature of these outer membrane vesicles appear to be responsible for overcoming the hydrophobic barrier necessary for the growth of T. thiooxidans on elemental sulfur.

Knickerbocker, C.; Nordstrom, D.K.; Southam, G.

2000-01-01

190

Zeolites Remove Sulfur From Fuels  

Science.gov (United States)

Zeolites remove substantial amounts of sulfur compounds from diesel fuel under relatively mild conditions - atmospheric pressure below 300 degrees C. Extracts up to 60 percent of sulfur content of high-sulfur fuel. Applicable to petroleum refineries, natural-gas processors, electric powerplants, and chemical-processing plants. Method simpler and uses considerably lower pressure than current industrial method, hydro-desulfurization. Yields cleaner emissions from combustion of petroleum fuels, and protects catalysts from poisoning by sulfur.

Voecks, Gerald E.; Sharma, Pramod K.

1991-01-01

191

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

192

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

193

Greene Machine  

Science.gov (United States)

The author of this article profiles the 37-year-old researcher Jay P. Greene and his controversial research studies on education. Most people learn early to trust the things they see first, but Greene adheres to a different creed. People are deceived by their own eyes. He believed that visual betrayal is as evident as it is in how people think…

Cavanagh, Sean

2004-01-01

194

SULFUR POLYMER ENCAPSULATION  

International Nuclear Information System (INIS)

Sulfur polymer cement (SPC) is a thermoplastic polymer consisting of 95 wt% elemental sulfur and 5 wt% organic modifiers to enhance long-term durability. SPC was originally developed by the U.S. Bureau of Mines as an alternative to hydraulic cement for construction applications. Previous attempts to use elemental sulfur as a construction material in the chemical industry failed due to premature degradation. These failures were caused by the internal stresses that result from changes in crystalline structure upon cooling of the material. By reacting elemental sulfur with organic polymers, the Bureau of Mines developed a product that successfully suppresses the solid phase transition and significantly improves the stability of the product. SPC, originally named modified sulfur cement, is produced from readily available, inexpensive waste sulfur derived from desulfurization of both flue gases and petroleum. The commercial production of SPC is licensed in the United States by Martin Resources (Odessa, Texas) and is marketed under the trade name Chement 2000. It is sold in granular form and is relatively inexpensive ((approx)$0.10 to 0.12/lb). Application of SPC for the treatment of radioactive, hazardous, and mixed wastes was initially developed and patented by Brookhaven National Laboratory (BNL) in the mid-1980s (Kalb and Colombo, 1985; Colombo et al., 1997). The process was subsequently investigated by the Commission of the European Communities (Van Dalen and Rijpkema,opean Communities (Van Dalen and Rijpkema, 1989), Idaho National Engineering Laboratory (Darnell, 1991), and Oak Ridge National Laboratory (Mattus and Mattus, 1994). SPC has been used primarily in microencapsulation applications but can also be used for macroencapsulation of waste. SPC microencapsulation has been demonstrated to be an effective treatment for a wide variety of wastes, including incinerator hearth and fly ash; aqueous concentrates such as sulfates, borates, and chlorides; blowdown solutions; soils; and sludges. It is not recommended for treatment of wastes containing high concentrations of nitrates because of potentially dangerous reactions between sulfur, nitrate, and trace quantities of organics. Recently, the process has been adapted for the treatment of liquid elemental mercury and mercury contaminated soil and debris

195

SULFUR POLYMER ENCAPSULATION.  

Energy Technology Data Exchange (ETDEWEB)

Sulfur polymer cement (SPC) is a thermoplastic polymer consisting of 95 wt% elemental sulfur and 5 wt% organic modifiers to enhance long-term durability. SPC was originally developed by the U.S. Bureau of Mines as an alternative to hydraulic cement for construction applications. Previous attempts to use elemental sulfur as a construction material in the chemical industry failed due to premature degradation. These failures were caused by the internal stresses that result from changes in crystalline structure upon cooling of the material. By reacting elemental sulfur with organic polymers, the Bureau of Mines developed a product that successfully suppresses the solid phase transition and significantly improves the stability of the product. SPC, originally named modified sulfur cement, is produced from readily available, inexpensive waste sulfur derived from desulfurization of both flue gases and petroleum. The commercial production of SPC is licensed in the United States by Martin Resources (Odessa, Texas) and is marketed under the trade name Chement 2000. It is sold in granular form and is relatively inexpensive ({approx}$0.10 to 0.12/lb). Application of SPC for the treatment of radioactive, hazardous, and mixed wastes was initially developed and patented by Brookhaven National Laboratory (BNL) in the mid-1980s (Kalb and Colombo, 1985; Colombo et al., 1997). The process was subsequently investigated by the Commission of the European Communities (Van Dalen and Rijpkema, 1989), Idaho National Engineering Laboratory (Darnell, 1991), and Oak Ridge National Laboratory (Mattus and Mattus, 1994). SPC has been used primarily in microencapsulation applications but can also be used for macroencapsulation of waste. SPC microencapsulation has been demonstrated to be an effective treatment for a wide variety of wastes, including incinerator hearth and fly ash; aqueous concentrates such as sulfates, borates, and chlorides; blowdown solutions; soils; and sludges. It is not recommended for treatment of wastes containing high concentrations of nitrates because of potentially dangerous reactions between sulfur, nitrate, and trace quantities of organics. Recently, the process has been adapted for the treatment of liquid elemental mercury and mercury contaminated soil and debris.

KALB, P.

2001-08-22

196

Allochromatium vinosum DsrC: Solution-State NMR Structure, Redox Properties and Interaction with DsrEFH, a Protein Essential for Purple Sulfur Bacterial Sulfur Oxidation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Sequenced genomes of dissimilatory sulfur-oxidizing and sulfate-reducing bacteria containing genes coding for DsrAB, the enzyme dissimilatory sulfite reductase, inevitably also contain the gene coding for the 12-kDa DsrC protein. DsrC is thought to have a yet unidentified role associated with the activity of DsrAB. Here we report the solution structure of DsrC from the sulfur-oxidizing purple sulfur bacterium Allochromatium vinosum determined with NMR spectroscopy in reducing conditions, and ...

Cort, John R.; Selan, Ute; Schulte, Andrea; Grimm, Frauke; Kennedy, Michael A.; Dahl, Christiane

2008-01-01

197

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

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

2007-04-15

198

Sulfur oxidation genes in diverse deep-sea viruses.  

Science.gov (United States)

Viruses are the most abundant biological entities in the oceans and a pervasive cause of mortality of microorganisms that drive biogeochemical cycles. Although the ecological and evolutionary effects of viruses on marine phototrophs are well recognized, little is known about their impact on ubiquitous marine lithotrophs. Here, we report 18 genome sequences of double-stranded DNA viruses that putatively infect widespread sulfur-oxidizing bacteria. Fifteen of these viral genomes contain auxiliary metabolic genes for the ? and ? subunits of reverse dissimilatory sulfite reductase (rdsr). This enzyme oxidizes elemental sulfur, which is abundant in the hydrothermal plumes studied here. Our findings implicate viruses as a key agent in the sulfur cycle and as a reservoir of genetic diversity for bacterial enzymes that underpin chemosynthesis in the deep oceans. PMID:24789974

Anantharaman, Karthik; Duhaime, Melissa B; Breier, John A; Wendt, Kathleen A; Toner, Brandy M; Dick, Gregory J

2014-05-16

199

Monitoring of bacteria in acid mine environments by reverse genome probing  

Energy Technology Data Exchange (ETDEWEB)

Traditionally, the study of microbial biodiversity in acid mine drainage (AMD) environments focused on species belonging to the genus Thiobacillus, but various other bacteria such as Leptospirillum ferroxidans, as well as certain fungi, flagellates, green algae, and yeasts have also been observed as minor constituents of microbiota in AMD. The purpose of this investigation was to apply reverse sample genome probing (RSGP) to the detection of acidophilic bacteria commonly recovered from AMD sites, and to describe the community of such environments. Analysis of enriched environmental samples by RSGP indicated that T. ferroxidans was enriched by a ferrous sulfate medium; although all thiobacilli grew in sulfur medium, T. thioxidans strains were the most prominent. Enrichment in glucose medium resulted in the selection of T. acidophilus strains. Analysis of DNA extracted without enrichment, from cells recovered from AMD water or sediment, showed that the major community components were homologous with T. ferroxidans and with T. acidophilus. A minority of community components showed similarity to T. thioxidans; none exhibited homology with L. ferroxidans. These results indicate that RSGP is a useful tool for monitoring microorganisms in AMD environments. There is also reason to believe that a better understanding of the effectiveness of different treatments of AMD could be obtained by using RSGP analysis to compare samples from treated and untreated acid mine effluents. 39 refs., 2 tabs., 5 figs.

Leveille, S. A.; Leduc, L. G.; Ferroni, G. D. [Laurentian Univ., Dept. of Biology, Sudbury, ON (Canada); Telang, A. J.; Voordouw, G. [Calgary Univ., Dept. of Biological Sciences, AB (Canada)

2001-05-01

200

Green tea  

Science.gov (United States)

... Weight loss. Taking a specific green tea extract (EGCG) seems to help moderately overweight people lose weight. ... Camellia theifera, Constituant Polyphénolique de Thé Vert, CPTV, EGCG, Epigallo Catechin Gallate, Épigallo-Catéchine Gallate, Epigallocatechin Gallate, ...

 
 
 
 
201

GM GREEN  

Science.gov (United States)

GM GREEN, from Earth Force Incorporated and General Motors, provides middle and high school-aged youth with educational opportunities to understand, improve and sustain the water resources in their communities.

2008-02-26

202

Sulfur dichloride, SCl2  

Science.gov (United States)

This month's molecule is sulfur dichloride, SCl2. This and other small inorganic molecules are discussed in the article by Matta and Gillespie. They describe electron density in molecules and how to analyze it to obtain information about molecular bonding and structure. Different depictions of electron density in SCl2 and other small molecules emphasize different aspects of their electron density and of the structures of the molecules.

203

Development of Efficient Flowsheet and Transient Modeling for Nuclear Heat Coupled Sulfur Iodine Cyclefor Hydrogen Production  

Energy Technology Data Exchange (ETDEWEB)

The realization of the hydrogen as an energy carrier for future power sources relies on a practical method of producing hydrogen in large scale with no emission of green house gases. Hydrogen is an energy carrier which can be produced by a thermochemical water splitting process. The Sulfur-Iodine (SI) process is an example of a water splitting method using iodine and sulfur as recycling agents.

Shripad T. Revankar; Nicholas R. Brown; Cheikhou Kane; Seungmin Oh

2010-05-01

204

Psychrotrophic ~Iydrolytic Bacteria from Antarctica &,Other I. Low Temperature Habitats  

Directory of Open Access Journals (Sweden)

Full Text Available Samples of water, soil,llake sediments and blue-green algal mats from Antarctica were'processed for enumeration, isolation and screening of psychrotrophic hydrolytic bacteria. Amylolytic bacteria were preponderant (75 per cent in the blue-green algal htat samples. Protease, lipase, an1ylase and urerse producing/bacteria were also isolated from the samples. ,Biochemical characteristics indicated that the isolates ;mainly comprised Pseudomonas and Bacillus species. Proteases and lipases of antarctic bacterial strains preferably hydrolysed denatured protein substrate and water soluble monomeric synthetic lipid substrates, respectively.

K.V. Ramana

2013-04-01

205

Lunar Sulfur Capture System  

Science.gov (United States)

The Lunar Sulfur Capture System (LSCS) protects in situ resource utilization (ISRU) hardware from corrosion, and reduces contaminant levels in water condensed for electrolysis. The LSCS uses a lunar soil sorbent to trap over 98 percent of sulfur gases and about two-thirds of halide gases evolved during hydrogen reduction of lunar soils. LSCS soil sorbent is based on lunar minerals containing iron and calcium compounds that trap sulfur and halide gas contaminants in a fixed-bed reactor held at temperatures between 250 and 400 C, allowing moisture produced during reduction to pass through in vapor phase. Small amounts of Earth-based polishing sorbents consisting of zinc oxide and sodium aluminate are used to reduce contaminant concentrations to one ppm or less. The preferred LSCS configuration employs lunar soil beneficiation to boost concentrations of reactive sorbent minerals. Lunar soils contain sulfur in concentrations of about 0.1 percent, and halogen compounds including chlorine and fluorine in concentrations of about 0.01 percent. These contaminants are released as gases such as H2S, COS, CS2,HCl, and HF during thermal ISRU processing with hydrogen or other reducing gases. Removal of contaminant gases is required during ISRU processing to prevent hardware corrosion, electrolyzer damage, and catalyst poisoning. The use of Earth-supplied, single-use consumables to entirely remove contaminants at the levels existing in lunar soils would make many ISRU processes unattractive due to the large mass of consumables relative to the mass of oxygen produced. The LSCS concept of using a primary sorbent prepared from lunar soil was identified as a method by which the majority of contaminants could be removed from process gas streams, thereby substantially reducing the required mass of Earth-supplied consumables. The LSCS takes advantage of minerals containing iron and calcium compounds that are present in lunar soil to trap sulfur and halide gases in a fixedbed reactor downstream of an in-ISRU process such as hydrogen reduction. The lunar-soil-sorbent trap is held at a temperature significantly lower than the operating temperature of the hydrogen reduction or other ISRU process in order to maximize capture of contaminants, but is held at a high enough temperature to allow moisture to pass through without condensing. The lunar soil benefits from physical beneficiation to remove ultrafine particles (to reduce pressure drop through a fixed bed reactor) and to upgrade concentrations of iron and/or calcium compounds (to improve reactivity with gaseous contaminants).

Berggren, Mark; Zubrin, Robert; Bostwick-White, Emily

2013-01-01

206

Understanding Sulfur Systematics in Large Igneous Provinces Using Sulfur Isotopes  

Science.gov (United States)

The eruption of the Siberian Traps coincided with perhaps the greatest environmental catastrophe in Earth's history, at the Permo-Triassic boundary. The source and magnitude of the volatile emissions, including sulfur, associated with the eruption remain poorly understood yet were critical in forcing environmental change. Two of the primary questions are how much sulfur gases were emitted during the eruptions and from where they were sourced. Primary melts carry dissolved sulfur from the mantle. Magmas ponding in sills and ascending through dykes may also assimilate sulfur from country rocks, as well as heat the country rocks and generate fluids through contact metamorphism. If the magmas interacted thermally, for prolonged periods, with sulfur-rich country rocks then it is probable that the sulfur budget of these eruptions might have been augmented considerably. This is exactly what we have shown recently for a basaltic sill emplaced in oil shale that fed eruptions of the British Tertiary Province, where surrounding sediments showed extensive desulfurization (Yallup et al. Geoch. Cosmochim. Acta, online, 2013). In the current study sulfur isotopes and trace element abundances are used to discriminate sulfur sources and to model magmatic processes for a suite of Siberian Traps sill and lava samples. Our bulk rock and pyrite geochemical analyses illustrate clearly their high abundance of 34S over 32S. The high 34S/32S has been noted previously and linked to assimilation of sulfur from sediments but may alternatively be inherited from the mantle plume source. With the aim of investigating the sulfur isotopic signature in the melt prior to devolatilization, we use secondary ion mass spectrometry (SIMS), for which a specific set of glass standards was synthesised. In order to understand how sulfur isotopes fractionate during degassing we have also conducted a parallel study of well-characterized tephras from Kilauea Volcano, where sulfur degassing behavior is well known.

Novikova, S.; Edmonds, M.; Turchyn, A. V.; Maclennan, J.; Svensen, H.; Frost, D. J.; Yallup, C.

2013-12-01

207

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

208

Growth kinetics of hydrogen sulfide oxidizing bacteria in corroded concrete from sewers  

International Nuclear Information System (INIS)

Hydrogen sulfide oxidation by microbes present on concrete surfaces of sewer pipes is a key process in sewer corrosion. The growth of aerobic sulfur oxidizing bacteria from corroded concrete surfaces was studied in a batch reactor. Samples of corrosion products, containing sulfur oxidizing bacteria, were suspended in aqueous solution at pH similar to that of corroded concrete. Hydrogen sulfide was supplied to the reactor to provide the source of reduced sulfur. The removal of hydrogen sulfide and oxygen was monitored. The utilization rates of both hydrogen sulfide and oxygen suggested exponential bacterial growth with median growth rates of 1.25 d-1 and 1.33 d-1 as determined from the utilization rates of hydrogen sulfide and oxygen, respectively. Elemental sulfur was found to be the immediate product of the hydrogen sulfide oxidation. When exponential growth had been achieved, the addition of hydrogen sulfide was terminated leading to elemental sulfur oxidation. The ratio of consumed sulfur to consumed oxygen suggested that sulfuric acid was the ultimate oxidation product. To the knowledge of the authors, this is the first study to determine the growth rate of bacteria involved in concrete corrosion with hydrogen sulfide as source of reduced sulfur.

209

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

210

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

211

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 me...

AlbertoParadela; SimonBeard

2011-01-01

212

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

213

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.

214

Going Green  

Centers for Disease Control (CDC) Podcasts

This podcast is for a general audience and provides information on how to recycle, re-use, and restore. It also covers the benefits of â??Going Green" on the environment, health, and social interaction.  Created: 4/18/2008 by National Center for Environmental Health (NCEH), ATSDR.   Date Released: 5/8/2008.

2008-04-18

215

Green Computing  

Directory of Open Access Journals (Sweden)

Full Text Available Green computing refers to the practice and procedures of using computing resources in an environment friendly way while maintaining overall computing performance. Global warming is the continuing rise in the average temperature of the Earth’s climate system due to a range of factors. Scientific understanding of the various causes of global warming has been increasing since the last decade. Climate change and associated impacts vary from region to region across the globe. Nowadays, weather behaviour is becoming extremely unpredictable throughout the globe. United Nations Framework Convention on Climate Change (UNFCCC is working relentlessly to achieve its objective of preventing dangerous anthropogenic (human-induced climate change. Owing to global warming, various regulations and laws related to environmental norms forces manufacturers of I.T equipments to meet various energy requirements. Green computing is a well balanced and sustainable approach towards the achievement of a greener, healthier and safer environment without compromising technological needs of the current and future generations. This paper is a survey of several important literature related to the field of green computing that emphasises the importance of green computing for sustainable development.

Biswajit Saha

2014-08-01

216

Emissions of biogenic sulfur gases from a danish estuary  

Science.gov (United States)

The diurnal variations in sulfur emission were studied at seven sites in a Danish estuary, Norsminde Fjord. The sites comprised grass vegetation, intertidal mud flats, accretions of green algae, an exposed shore and a river outlet. Direct measurements of emission rates from soil and water were done by a dynamic flux chamber technique in connection with gas Chromatographie detection and separation of the cryogenically trapped sulfur gases. Sulfur gas concentrations in air and sea water were measured together with emission rates at 0.5-1 h intervals over 25-40 h periods. DMS was the most important sulfur gas released from grass and algae, while mostly H 2S was released from intertidal mud flats. OCS, CH 3SH and CS 2 were released from most sites at lower rates. Emission of DMS followed the daylight variations, often with a delay towards maximum emission rates in the evening. H 2S was mostly emitted at night or in short outbursts during low tides. Total sulfur emission rates were 1-10?mol Sm -2 d -1. Extreme rates of 335?mol DMSm -2 d -1 were measured over decomposing green algae ( Ulva lactuca). H 2S emission fractions were < 10 -6 to 2.10 -4. H 2S was detected, along with DMS, CH 3SH, OCS and CS 2, in the oxic seawater of the estuary at diurnal mean concentrations of 0.1-6.5nmol S/ol -1. This may indicate a more widespread occurrence of H 2S in shallow, near-shore waters at nanomolar levels.

Barker Jørgensen, Bo; Okholm-Hansen, Bolette

217

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)

218

Volume efficient sodium sulfur battery  

Science.gov (United States)

In accordance with the teachings of this specification, a sodium sulfur battery is formed as follows. A plurality of box shaped sulfur electrodes are provided, the outer surfaces of which are defined by an electrolyte material. Each of the electrodes have length and width dimensions substantially greater than the thicknesses thereof as well as upwardly facing surface and a downwardly facing surface. An electrode structure is contained in each of the sulfur electrodes. A holding structure is provided for holding the plurality of sulfur electrodes in a stacked condition with the upwardly facing surface of one sulfur electrode in facing relationship to the downwardly facing surface of another sulfur electrode thereabove. A small thickness dimension separates each of the stacked electrodes thereby defining between each pair of sulfur electrodes a volume which receives the sodium reactant. A reservoir is provided for containing sodium. A manifold structure interconnects the volumes between the sulfur electrodes and the reservoir. A metering structure controls the flow of sodium between the reservoir and the manifold structure.

Mikkor, Mati (Ann Arbor, MI)

1980-01-01

219

Sulfur starvation and chromium tolerance in Scenedesmus acutus: a possible link between metal tolerance and the regulation of sulfur uptake/assimilation processes.  

Science.gov (United States)

In a laboratory-selected Cr-tolerant strain of the unicellular green alga Scenedesmus acutus, the capacity to synthesize higher amounts of cysteine (Cys) and reduced glutathione (GSH) than the wild-type was demonstrated to underlie tolerance to Cd and Cr(VI). In photosynthetic organisms sulfate constitutes the main sulfur source for the biosynthesis of GSH and its precursor Cys, hence it was hypothesized that the sensitivity of the two strains to Cr(VI) could be modified after culturing in sulfate-deprived medium. Both strains were grown in the presence of different concentrations or in the absence of sulfate (sulfur-starved) and then assayed for Cr(VI) tolerance in standard medium. Unstarved, sulfur-starved and sulfur-replete cells (cells maintained in standard medium after S-starvation) were analysed for Cys, GSH and sulfur content. Sulfur-starved cells showed a greater tolerance to Cr(VI) than unstarved ones. The increased tolerance was ascribable to a transient physiological change and can be considered as specifically due to sulfur deprivation, since it was lost after a 3-day culture in standard medium and was not exhibited by nitrogen-starved cells. The comparison between Cys, GSH and sulfur content in sulfur-starved and sulfur-replete cells of the two strains suggests that the higher tolerance to Cr(VI) after S-starvation could depend on the up-regulation of sulfate uptake mechanisms, and that the primary reason for the higher tolerance to chromium in the selected strain could be due to greater sensitivity to the decrease in negative intracellular end-products (free Cys and GSH) leading to an earlier up-regulation of sulfate assimilation processes. PMID:17727973

Gorbi, Gessica; Zanni, Corrado; Corradi, Maria Grazia

2007-10-30

220

The Museum of Bacteria  

Science.gov (United States)

The Museum of Bacteria serves as a clearinghouse of Web links on bacteria and bacteriology and also provides "crystal-clear information about many aspects of bacteria." The Museum of Bacteria is provided by the Foundation of Bacteria, a non-profit organization dedicated to promoting the field of bacteriology. Links are selected for a general audience, although one section is geared toward professionals in the field. Some of the latest features of the Museum are an "exhibit" on the good bacteria found in food and a Student Hall where students can present their own bacteria-related projects.

 
 
 
 
221

Microbial stabilization of sulfur-laden sorbents. Technical report, 1 December 1993--28 February 1994  

Energy Technology Data Exchange (ETDEWEB)

Clean coal technologies that involve limestone for sulfur capture generate lime/limestone products laden with sulfur at various oxidation states. If sulfur is completely stabilized as sulfate, the spend sorbent is ready for commercial utilization as gypsum. However, the presence of reduced sulfur species required additional processing. Thermal oxidation of reduced sulfur can result in undesirable release of SO{sub 2}. Microbial oxidation might provide an inexpensive and effective alternative. Sorbents laden with reduced forms of sulfur such as sulfide, sulfite, or various polythionate species serve as growth substrates for sulfur-oxidizing bacteria, which have the potential to convert all sulfur to sulfate. This quarter, efforts focused on treating the aqueous phase of a waste sorbent obtained from an inhibited wet scrubbing process. Although two named strains, Thiobacillus neapolitanus ATCC 23639 and ATCC 23641, failed; the isolate TQ1 rapidly oxidized thiosalts, producing sulfate. The Virtis Fermentor arrived, so that experiments with TQ1 have been scaled up to 1.5 liters with temperature, aeration, and pH control.

Miller, K.W. [Illinois State Univ., Normal, IL (United States)

1994-06-01

222

Green Computing  

Directory of Open Access Journals (Sweden)

Full Text Available Green computing is all about using computers in a smarter and eco-friendly way. It is the environmentally responsible use of computers and related resources which includes the implementation of energy-efficient central processing units, servers and peripherals as well as reduced resource consumption and proper disposal of electronic waste .Computers certainly make up a large part of many people lives and traditionally are extremely damaging to the environment. Manufacturers of computer and its parts have been espousing the green cause to help protect environment from computers and electronic waste in any way.Research continues into key areas such as making the use of computers as energy-efficient as Possible, and designing algorithms and systems for efficiency-related computer technologies.

K. Shalini

2013-01-01

223

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

224

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

225

Sulfur dioxide oxidation catalyst and process  

International Nuclear Information System (INIS)

A catalytic process for the oxidation of sulfur-containing gases , E.G., sulfur dioxide and simultaneous production of sulfuric acid wherein a sulfur-containing gas is reacted with an oxygencontaining gas in the presence of a catalyst comprising an iron group metal on a solid support comprising a zeolite in a silicaalumina matrix

226

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

227

Analysis of Bacterial Community Structure in Sulfurous-Oil-Containing Soils and Detection of Species Carrying Dibenzothiophene Desulfurization (dsz) Genes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The selective effects of sulfur-containing hydrocarbons, with respect to changes in bacterial community structure and selection of desulfurizing organisms and genes, were studied in soil. Samples taken from a polluted field soil (A) along a concentration gradient of sulfurous oil and from soil microcosms treated with dibenzothiophene (DBT)-containing petroleum (FSL soil) were analyzed. Analyses included plate counts of total bacteria and of DBT utilizers, molecular community profiling via soi...

Duarte, Gabriela Frois; Rosado, Alexandre Soares; Seldin, Lucy; Araujo, Welington; Elsas, Jan Dirk

2001-01-01

228

Bleach vs. Bacteria  

Science.gov (United States)

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

229

Effect of electron donors on the fractionation of sulfur isotopes by a marine Desulfovibrio sp.  

Science.gov (United States)

Sulfur isotope effects produced by microbial dissimilatory sulfate reduction are used to reconstruct the coupled cycling of carbon and sulfur through geologic time, to constrain the evolution of sulfur-based metabolisms, and to track the oxygenation of Earth's surface. In this study, we investigate how the coupling of carbon and sulfur metabolisms in batch and continuous cultures of a recently isolated marine sulfate reducing bacterium DMSS-1, a Desulfovibrio sp ., influences the fractionation of sulfur isotopes. DMSS-1 grown in batch culture on seven different electron donors (ethanol, glycerol, fructose, glucose, lactate, malate and pyruvate) fractionates 34S/ 32S ratio from 6‰ to 44‰, demonstrating that the fractionations by an actively growing culture of a single incomplete oxidizing sulfate reducing microbe can span almost the entire range of previously reported values in defined cultures. The magnitude of isotope effect correlates well with cell specific sulfate reduction rates (from 0.7 to 26.1 fmol/cell/day). DMSS-1 grown on lactate in continuous culture produces a larger isotope effect (21-37‰) than the lactate-grown batch culture (6‰), indicating that the isotope effect also depends on the supply rate of the electron donor and microbial growth rate. The largest isotope effect in continuous culture is accompanied by measurable changes in cell length and cellular yield that suggest starvation. The use of multiple sulfur isotopes in the model of metabolic fluxes of sulfur shows that the loss of sulfate from the cell and the intracellular reoxidation of reduced sulfur species contribute to the increase in isotope effects in a correlated manner. Isotope fractionations produced during sulfate reduction in the pure culture of DMSS-1 expand the previously reported range of triple sulfur isotope effects ( 32S, 33S, and 34S) by marine sulfate reducing bacteria, implying that microbial sulfur disproportionation may have a smaller 33S isotopic fingerprint than previously thought.

Sim, Min Sub; Ono, Shuhei; Donovan, Katie; Templer, Stefanie P.; Bosak, Tanja

2011-08-01

230

Sonoluminescence of elementary sulfur melt  

Science.gov (United States)

The sonoluminescence of liquid sulfur has been observed for temperatures of 120-180°C. The sonoluminescence intensity of the sulfur melt is 109 photons/s at 120°C. As the temperature increases, the luminescence intensity decreases nonmonotonically, a maximum is observed at 160-175°C, and cavitation and luminescence cease at 180°C. The dependence obtained correlates with the temperature dependence of the viscosity of the sulfur melt. The sonoluminescence spectrum obtained with a resolution of 10 nm for 130-150°C contains one band with ?max = 560 nm, the emitter of which is likely an (S+)* ion. When the melt is saturated with argon, the sonoluminescence intensity increases by an order of magnitude; in this case, the spectral band shape changes only slightly. The results confirm the “electric” theory of multibubble sonoluminescence. In the process of the sonolysis of the sulfur melt, biradical fragments are formed in cavitation bubbles consisting of sulfur molecules, which initially have the form of cyclooctasulfur S8. These fragments can enter into the melts and can be involved in various chemical reactions. This circumstance makes it possible to recommend ultrasonic activation for reactions of sulfurization of hydrocarbons.

Abdrakhmanov, A. M.; Sharipov, G. L.; Rusakov, I. V.; Akhmetova, V. R.; Bulgakov, R. G.

2007-06-01

231

Lactic Acid Bacteria  

Science.gov (United States)

This on-line exercise is focused on lactic acid bacteria, a group of related bacteria that produce lactic acid as a result of carbohydrate fermentation. It includes a protocol for the enrichment of lactic acid bacteria from enriched samples (like yogurt, sauerkraut, decaying plant matter, and tooth plaque). Three parameters are measured: growth, culture diversity, and pH. The exercise also includes instructions for the isolation of some of these bacteria by using the streak-plate method.

2010-03-01

232

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 hes at the environmental and agricultural levels. (J.S.)

233

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

234

Distribution and size fractionation of elemental sulfur in aqueous environments: The Chesapeake Bay and Mid-Atlantic Ridge  

Science.gov (United States)

Elemental sulfur is an important intermediate of sulfide oxidation and may be produced via abiotic and biotic pathways. In this study the concentration and size fractionation of elemental sulfur were measured in two different sulfidic marine environments: the Chesapeake Bay and buoyant hydrothermal vent plumes along the Mid-Atlantic Ridge. Nanoparticulate sulfur (<0.2 ?m) was found to comprise up to 90% of the total elemental sulfur in anoxic deep waters of the Chesapeake Bay. These data were compared with previous studies of elemental sulfur, and represent one of the few reports of nanoparticulate elemental sulfur in the environment. Additionally, a strain of phototrophic sulfide oxidizing bacteria isolated from the Chesapeake Bay was shown to produce elemental sulfur as a product of sulfide oxidation. Elemental sulfur concentrations are also presented from buoyant hydrothermal vent plumes located along the Mid-Atlantic Ridge. In the Mid-Atlantic Ridge plume, S0 concentrations up to 33 ?M were measured in the first meter of rising plumes at three different vent sites, and nanoparticulate S0 was up to 44% of total elemental sulfur present.

Findlay, Alyssa J.; Gartman, Amy; MacDonald, Daniel J.; Hanson, Thomas E.; Shaw, Timothy J.; Luther, George W.

2014-10-01

235

The Determinants of Green Radical and Incremental Innovation Performance: Green Shared Vision, Green Absorptive Capacity, and Green Organizational Ambidexterity  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study proposes a new concept, green organisational ambidexterity, that integrates green exploration learning and green exploitation learning simultaneously. Besides, this study argues that the antecedents of green organisational ambidexterity are green shared vision and green absorptive capacity and its consequents are green radical innovation performance and green incremental innovation performance. The results demonstrate that green exploration learning partially mediates the positive ...

Yu-Shan Chen; Ching-Hsun Chang; Yu-Hsien Lin

2014-01-01

236

40 CFR 52.1881 - Control strategy: Sulfur oxides (sulfur dioxide).  

Science.gov (United States)

...a maintenance plan for sulfur dioxide...submitted maintenance plans for Coshocton...submitted maintenance plans for sulfur dioxide...By-product coke oven gas means the...producing steam by heat transfer. ...xiii) Sulfur recovery plant...

2010-07-01

237

The Green Power Network: Buying Green Power  

Science.gov (United States)

The Green Power Network (GPN), operated and maintained by the National Renewable Energy Laboratory for the U.S. Department of Energy, provides news and information on green power markets and related activities. Here, they supply a great tool for discovering green power availability throughout the United States. Clicking on any state will provide visitors with any green power including utility green pricing programs, retail green power products offered in competitive utility markets, and renewable energy certificate products (REC) sold separate from electricity. This will be a useful tool for instructors or students interested in renewable energy technologies.

238

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.

1369-13-01

239

Bacteria Are Everywhere!  

Science.gov (United States)

Students are introduced to the concept of engineering biological organisms and studying their growth to be able to identify periods of fast and slow growth. They learn that bacteria are found everywhere, including on the surfaces of our hands. Student groups study three different conditions under which bacteria are found and compare the growth of the individual bacteria from each source. In addition to monitoring the quantity of bacteria from differ conditions, they record the growth of bacteria over time, which is an excellent tool to study binary fission and the reproduction of unicellular organisms.

AMPS GK-12 Program,

240

Analysis of the sulfur origin and sulfur isotopic compositions of acid rain  

International Nuclear Information System (INIS)

Acid rain has been one of the most serious environment problems in the world and the study of sulfur isotope can help us find the sulfur source, composition and have important significance for research to harness acid rain. This paper mainly revolves around three aspects to introduce the significance of sulfur isotopic study, they are sulfur isotopes in coals, sulfur isotopic compositions of surface water and sulfur isotopes in wheat. (authors)

 
 
 
 
241

Green Revolution  

Science.gov (United States)

Coming up with better ways to get where we need to go and power the lives we live requires development of new technologies, along with research to help us minimize the impact of these technologies on our environment. The overall goal of this series is to encourage people to ask questions and look beyond fossil fuels for innovative solutions to our ever-growing energy needs. Interest in science and technology provides the necessary foundation for our future in a world powered by clean energy. The series also provides insight into what careers in science, engineering and other topics related to clean energy technologies are really like. There are videos about wind, solar, green roofs, smart grid, biomass, microbes and city cars.

242

Green Roofs and Green Building Rating Systems  

Directory of Open Access Journals (Sweden)

Full Text Available The environmental benefits for green building from the Leadership in Energy and Environment Design (LEED and Ecology, Energy, Waste, and Health (EEWH rating systems have been extensively investigated; however, the effect of green roofs on the credit-earning mechanisms is relatively unexplored. This study is concerned with the environmental benefits of green roofs with respect to sustainability, stormwater control, energy savings, and water resources. We focused on the relationship between green coverage and the credits of the rating systems, evaluated the credits efficiency, and performed cost analysis. As an example, we used a university building in Keelung, Northern Taiwan. The findings suggest that with EEWH, the proposed green coverage is 50–75%, whereas with LEED, the proposed green coverage is 100%. These findings have implications for the application of green roofs in green building.

Liaw

2015-01-01

243

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

Science.gov (United States)

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

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

2014-01-01

244

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

245

Response to copper of Acidithiobacillus ferrooxidans ATCC 23270 grown in elemental sulfur.  

Science.gov (United States)

The response of Acidithiobacillus ferrooxidans ATCC 23270 to copper was analyzed in sulfur-grown cells by using quantitative proteomics. Forty-seven proteins showed altered levels in cells grown in the presence of 50 mM copper sulfate. Of these proteins, 24 were up-regulated and 23 down-regulated. As seen before in ferrous iron-grown cells, there was a notorious up-regulation of RND-type Cus systems and different RND-type efflux pumps, indicating that these proteins are very important in copper resistance. Copper also triggered the down-regulation of the major outer membrane porin of A. ferrooxidans in sulfur-grown bacteria, suggesting they respond to the metal by decreasing the influx of cations into the cell. On the contrary, copper in sulfur-grown cells caused an overexpression of putative TadA and TadB proteins known to be essential for biofilm formation in bacteria. Surprisingly, sulfur-grown microorganisms showed increased levels of proteins related with energy generation (rus and petII operons) in the presence of copper. Although rus operon is overexpressed mainly in cells grown in ferrous iron, the up-regulation of rusticyanin in sulfur indicates a possible role for this protein in copper resistance as well. Finally, copper response in A. ferrooxidans appears to be influenced by the substrate being oxidized by the microorganism. PMID:25041950

Almárcegui, Rodrigo J; Navarro, Claudio A; Paradela, Alberto; Albar, Juan Pablo; von Bernath, Diego; Jerez, Carlos A

2014-11-01

246

Fe-S Cluster Assembly Pathways in Bacteria  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Summary: Iron-sulfur (Fe-S) clusters are required for critical biochemical pathways, including respiration, photosynthesis, and nitrogen fixation. Assembly of these iron cofactors is a carefully controlled process in cells to avoid toxicity from free iron and sulfide. Multiple Fe-S cluster assembly pathways are present in bacteria to carry out basal cluster assembly, stress-responsive cluster assembly, and enzyme-specific cluster assembly. Although biochemical and genetic characterization is ...

Ayala-castro, Carla; Saini, Avneesh; Outten, F. Wayne

2008-01-01

247

Sulfur-doped graphene derived from cycled lithium-sulfur batteries as a metal-free electrocatalyst for the oxygen reduction reaction.  

Science.gov (United States)

Heteroatom-doped carbon materials have been extensively investigated as metal-free electrocatalysts to replace commercial Pt/C catalysts in oxygen reduction reactions in fuel cells and Li-air batteries. However, the synthesis of such materials usually involves high temperature or complicated equipment. Graphene-based sulfur composites have been recently developed to prolong the cycling life of Li-S batteries, one of the most attractive energy-storage devices. Given the high cost of graphene, there is significant demand to recycle and reuse graphene from Li-S batteries. Herein, we report a green and cost-effective method to prepare sulfur-doped graphene, achieved by the continuous charge/discharge cycling of graphene-sulfur composites in Li-S batteries. This material was used as a metal-free electrocatalyst for the oxygen reduction reaction and shows better electrocatalytic activity than pristine graphene and better methanol tolerance durability than Pt/C. PMID:25483872

Ma, Zhaoling; Dou, Shuo; Shen, Anli; Tao, Li; Dai, Liming; Wang, Shuangyin

2015-02-01

248

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 comons are concerned. The most privileged companies can expect quotas increased by tens of percent. (author)

249

Darwin y las bacterias Darwin and bacteria  

Directory of Open Access Journals (Sweden)

Full Text Available Con motivo de cumplirse 200 años del natalicio de Darwin y 150 desde la publicación de El Origen de las Especies, se revisa su obra buscando alguna mención de las bacterias, a las cuales el gran naturalista parece, o bien no haber conocido, algo muy difícil en un momento en que causaban sensación en el mundo científico, o bien haber ignorado deliberadamente, porque no encontraba para ellas lugar en su teoría de la evolución. Las bacterias, por su parte, afectaron malamente su vida familiar, falleciendo uno de sus hijos de escarlatina y su hija favorita, Arme, de una tuberculosis agravada por el mismo mal que mató a su hermano. El propio Darwin, desde el regreso del Beagle afectado por una enfermedad crónica hasta ahora no dilucidada, podría haber sufrido de la enfermedad de Chagas, cuyo agente etiológico, si bien no es una bacteria, tiene un similar nivel en la escala evolutiva.As in 2009 the scientific world celebrates two hundreds years from the birthday of Charles Darwin and one hundred and fifty from the publication of The Origin of Species, an analysis of his complete work is performed, looking for any mention of bacteria. But it seems that the great naturahst never took knowledge about its existence, something rather improbable in a time when the discovery of bacteria shook the medical world, or he deliberately ignored them, not finding a place for such microscopic beings into his theory of evolution. But the bacteria badly affected his familiar life, killing scarlet fever one of his children and worsening to death the evolution of tuberculosis of his favourite Annie. Darwin himself could suffer the sickness of Chagas, whose etiological agent has a similar level to bacteria in the scale of evolution.

Walter Ledermann D

2009-02-01

250

Darwin y las bacterias / Darwin and bacteria  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish Con motivo de cumplirse 200 años del natalicio de Darwin y 150 desde la publicación de El Origen de las Especies, se revisa su obra buscando alguna mención de las bacterias, a las cuales el gran naturalista parece, o bien no haber conocido, algo muy difícil en un momento en que causaban sensación en [...] el mundo científico, o bien haber ignorado deliberadamente, porque no encontraba para ellas lugar en su teoría de la evolución. Las bacterias, por su parte, afectaron malamente su vida familiar, falleciendo uno de sus hijos de escarlatina y su hija favorita, Arme, de una tuberculosis agravada por el mismo mal que mató a su hermano. El propio Darwin, desde el regreso del Beagle afectado por una enfermedad crónica hasta ahora no dilucidada, podría haber sufrido de la enfermedad de Chagas, cuyo agente etiológico, si bien no es una bacteria, tiene un similar nivel en la escala evolutiva. Abstract in english As in 2009 the scientific world celebrates two hundreds years from the birthday of Charles Darwin and one hundred and fifty from the publication of The Origin of Species, an analysis of his complete work is performed, looking for any mention of bacteria. But it seems that the great naturahst never t [...] ook knowledge about its existence, something rather improbable in a time when the discovery of bacteria shook the medical world, or he deliberately ignored them, not finding a place for such microscopic beings into his theory of evolution. But the bacteria badly affected his familiar life, killing scarlet fever one of his children and worsening to death the evolution of tuberculosis of his favourite Annie. Darwin himself could suffer the sickness of Chagas, whose etiological agent has a similar level to bacteria in the scale of evolution.

Walter, Ledermann D.

2009-02-01

251

Viability of bacteria in dental calculus - A microbiological study  

Directory of Open Access Journals (Sweden)

Full Text Available Aim: The aim of this study was (1 To investigate the viability of bacteria within supragingival and subgingival calculus, (2 To examine motility of bacteria, and (3 To identify bacterial morphotypes in calculus. Materials and Methods: Supra and subgingival calculus were harvested from 30 subjects having clinical evidence of chronic inflammatory periodontal disease and were divided into two groups . Samples from both groups were immediately transported to the Department of Microbiology for gram staining, acridine orange staining, bacterial culture and to the Department of Oral Pathology for dark field microscopy. Results: Gram staining revealed presence of bacteria within the samples. Dark field microscopic examination revealed presence of filamentous organisms, spirochetes, and motile short bacilli. Acridine orange fluorescent stain showed that the viable bacteria appeared apple green. Bacterial culture revealed presence of a variety of aerobic organisms. Conclusion: From the results, it appeared that viable bacteria were present within calculus especially within internal channels and lacunae.

Moolya Nikesh

2010-01-01

252

Viability of bacteria in dental calculus – A microbiological study  

Science.gov (United States)

Aim: The aim of this study was (1) To investigate the viability of bacteria within supragingival and subgingival calculus, (2) To examine motility of bacteria, and (3) To identify bacterial morphotypes in calculus. Materials and Methods: Supra and subgingival calculus were harvested from 30 subjects having clinical evidence of chronic inflammatory periodontal disease and were divided into two groups. Samples from both groups were immediately transported to the Department of Microbiology for gram staining, acridine orange staining, bacterial culture and to the Department of Oral Pathology for dark field microscopy. Results: Gram staining revealed presence of bacteria within the samples.Dark field microscopic examination revealed presence of filamentous organisms, spirochetes, and motile short bacilli. Acridine orange fluorescent stain showed that the viable bacteria appeared apple green. Bacterial culture revealed presence of a variety of aerobic organisms. Conclusion: From the results, it appeared that viable bacteria were present within calculus especially within internal channels and lacunae. PMID:21731246

Moolya, Nikesh N.; Thakur, Srinath; Ravindra, S.; Setty, Swati B.; Kulkarni, Raghavendra; Hallikeri, Kaveri

2010-01-01

253

Assimilatory Sulfur Metabolism in Marine Microorganisms: Sulfur Metabolism, Protein Synthesis, and Growth of Alteromonas luteo-violaceus and Pseudomonas halodurans During Perturbed Batch Growth †  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The antibiotic protein synthesis inhibitor chloramphenicol specifically blocked the incorporation of [35S]sulfate into the residue protein of two marine bacteria, Pseudomonas halodurans and Alteromonas luteo-violaceus. Simultaneous inhibition of total protein synthesis occurred, but incorporation of 35S into low-molecular-weight organic compounds continued. A. luteo-violaceus rapidly autolyzed, with similar reduction in cell counts, total culture protein and cellular sulfur, whereas P. halodu...

Cuhel, Russell L.; Taylor, Craig D.; Jannasch, Holger W.

1982-01-01

254

Green nanotechnology  

Science.gov (United States)

Nanotechnology, in particular nanophotonics, is proving essential to achieving green outcomes of sustainability and renewable energy at the scales needed. Coatings, composites and polymeric structures used in windows, roof and wall coatings, energy storage, insulation and other components in energy efficient buildings will increasingly involve nanostructure, as will solar cells. Nanostructures have the potential to revolutionize thermoelectric power and may one day provide efficient refrigerant free cooling. Nanomaterials enable optimization of optical, opto-electrical and thermal responses to this urgent task. Optical harmonization of material responses to environmental energy flows involves (i) large changes in spectral response over limited wavelength bands (ii) tailoring to environmental dynamics. The latter includes engineering angle of incidence dependencies and switchable (or chromogenic) responses. Nanomaterials can be made at sufficient scale and low enough cost to be both economic and to have a high impact on a short time scale. Issues to be addressed include human safety and property changes induced during manufacture, handling and outdoor use. Unexpected bonuses have arisen in this work, for example the savings and environmental benefits of cool roofs extend beyond the more obvious benefit of reduced heat flows from the roof into the building.

Smith, Geoff B.

2011-10-01

255

Multidrug Resistance in Bacteria  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Large amounts of antibiotics used for human therapy, as well as for farm animals and even for fish in aquaculture, resulted in the selection of pathogenic bacteria resistant to multiple drugs. Multidrug resistance in bacteria may be generated by one of two mechanisms. First, these bacteria may accumulate multiple genes, each coding for resistance to a single drug, within a single cell. This accumulation occurs typically on resistance (R) plasmids. Second, multidrug resistance may also occur b...

Nikaido, Hiroshi

2009-01-01

256

Genomics of Probiotic Bacteria  

Science.gov (United States)

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

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

257

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

258

Introduction to Bacteria  

Science.gov (United States)

This science site has students research how bacteria move, where they live, and how they reproduce; learn how bacteria can be helpful or harmful; and create a design illustrating what they have learned about bacteria. Included in the lesson plan are the objectives, needed materials and Web sites, procedures, discussion questions, evaluation, extensions, suggested reading, and vocabulary. Teachers can link to Teaching Tools to create custom worksheets, puzzles, and quizzes. A printable version of the lesson plan can be downloaded. The video Bacteria, Viruses and Allergies can be purchased and comprehension questions and answers can be downloaded.

Discoveryschool.com; Fenichel, Marilyn

2007-12-12

259

ALGAE-BACTERIA INTERACTION IN A LIGHT-DARK CYCLE (JOURNAL VERSION)  

Science.gov (United States)

Nutrient and population dynamics accompanying algae-bacteria interaction were observed in unialgal, 18-liter batch cultures during a light-dark cycle. The green alga Chlorella vulgaris, and the nitrogen fixing blue-green Anabaena flos-aquae were inoculated with an aquatic communi...

260

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

 
 
 
 
261

Mercury-Sulfur Interactions in an Experimental Peatland  

Science.gov (United States)

The mercury and sulfur cycles are intimately linked. For example, the production of methylmercury, the mercury species that accumulates in biota, is strongly controlled by the activity of sulfate-reducing bacteria. Of the many types of wetlands, peatlands and especially bogs are important areas of methylmercury production, partly because the hydrological and biogeochemical conditions in peatlands support anaerobes like sulfate-reducing bacteria. Given the vast coverage of peatlands in the northern U.S. and in Canada (> 1million km2), the impact of peatlands on large-scale mercury cycling could be enormous. Our current understanding of sulfur-mercury interactions in peatlands is mostly from short-duration or fine-scale experimentation, which makes extrapolation tenuous. Currently, the positive relationship between sulfate loading and methylmercury production is relatively well understood. However, the converse, how methylmercury pools are affected by reductions in sulfate loading, is entirely unknown. An important, policy-relevant question is whether reductions in sulfate deposition could lead to reductions in methylmercury loads in peatland biota, and how quickly these reductions might occur. These issues were addressed in a long-term, ecosystem-scale experiment in which sulfate loads were elevated through simulated rainfall to half of a 2-hectare peatland in northern Minnesota. Wet sulfate deposition was increased to the experimental half of a wetland from 2001 through 2006. In 2006, this increased deposition was halted in half of the experimental area (referred to as the "recovery" area thereafter), while increased deposition continued in the other half of the experimental area until the end of 2008 ("experimental"). Once increased sulfate deposition ceased, sulfate concentrations returned to background (control) levels within one year. Methylmercury concentrations in pore waters, peat, and invertebrates took three to five years to decrease to control levels once wet sulfate deposition was reduced, but important spatial patterns emerged that affected the level of impact. We believe that the impact of atmospherically-deposited sulfate on methylmercury production is relatively short-lived because sulfate is sequestered in increasingly recalcitrant organic sulfur pools over time, which reduces the activity of sulfate-reducing bacteria and tips the mercury methylation-demethylation scales in favor of demethylation. These results also suggest that further controls on atmospheric sulfur emissions and deposition could be as important as reductions in mercury emissions to arrive at significant reductions in the mercury load of peatland biota.

Mitchell, C. P.; Coleman-Wasik, J.; Engstrom, D. R.; Swain, E.; Monson, B.; Eggert, S.; Jeremiason, J.; Balogh, S. J.; Branfireun, B. A.; Kolka, R.

2011-12-01

262

Sulfur metabolism in the biosynthesis of monobactams.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We studied the biosynthesis of monobactams with respect to sulfur metabolism in Chromobacterium violaceum, Acetobacter sp., and Agrobacterium radiobacter. All three organisms used inorganic sulfur for monobactam production. When sulfur-containing amino acids were assayed as a source of sulfur for monobactam production, C. violaceum used cystine but not cysteine or methionine, Acetobacter sp. used all three compounds, and A. radiobacter used none. 35S from cysteine, methionine, and sodium sulf...

O Sullivan, J.; Souser, M. L.; Kao, C. C.; Aklonis, C. A.

1983-01-01

263

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.

264

Stoichiometric modeling of oxidation of reduced inorganic sulfur compounds (Riscs) in Acidithiobacillus thiooxidans.  

Science.gov (United States)

The prokaryotic oxidation of reduced inorganic sulfur compounds (RISCs) is a topic of utmost importance from a biogeochemical and industrial perspective. Despite sulfur oxidizing bacterial activity is largely known, no quantitative approaches to biological RISCs oxidation have been made, gathering all the complex abiotic and enzymatic stoichiometry involved. Even though in the case of neutrophilic bacteria such as Paracoccus and Beggiatoa species the RISCs oxidation systems are well described, there is a lack of knowledge for acidophilic microorganisms. Here, we present the first experimentally validated stoichiometric model able to assess RISCs oxidation quantitatively in Acidithiobacillus thiooxidans (strain DSM 17318), the archetype of the sulfur oxidizing acidophilic chemolithoautotrophs. This model was built based on literature and genomic analysis, considering a widespread mix of formerly proposed RISCs oxidation models combined and evaluated experimentally. Thiosulfate partial oxidation by the Sox system (SoxABXYZ) was placed as central step of sulfur oxidation model, along with abiotic reactions. This model was coupled with a detailed stoichiometry of biomass production, providing accurate bacterial growth predictions. In silico deletion/inactivation highlights the role of sulfur dioxygenase as the main catalyzer and a moderate function of tetrathionate hydrolase in elemental sulfur catabolism, demonstrating that this model constitutes an advanced instrument for the optimization of At. thiooxidans biomass production with potential use in biohydrometallurgical and environmental applications. PMID:23436458

Bobadilla Fazzini, Roberto A; Cortés, Maria Paz; Padilla, Leandro; Maturana, Daniel; Budinich, Marko; Maass, Alejandro; Parada, Pilar

2013-08-01

265

Overview of research on corrosive sulfur in transformer oil  

Energy Technology Data Exchange (ETDEWEB)

This paper gives an overview of research on corrosive sulfur in transformer oil. The mechanism of transformer failure due to corrosive sulfur, the test methods for total sulfur and corrosive sulfur, the source of corrosive sulfur, the basic groups of sulfur and sulfur compounds in crude oil, and possible mitigation techniques for cuprous sulfide formation are introduced. Additionally, potentially promising research topics on corrosive sulfur are discussed. (orig.)

Cao Shun' an; Li Rui; Qian Yihua; Sheng Kai [Wuhan Univ., Hubei Province (China). Dept. of Water Quality Engineering

2008-08-15

266

Biogeochemistry of sulfur and iron in Thioploca-colonized surface sediments in the upwelling area off central Chile  

DEFF Research Database (Denmark)

The biogeochemistry of sedimentary sulfur was investigated on the continental shelf off central Chile at water depths between 24 and 88 m under partial influence of an oxygen minimum zone. Dissolved and solid iron and sulfur species, including the sulfur intermediates sulfite, thiosulfate, and elemental sulfur, were analyzed at high resolution in the top 20 cm. All stations were characterized by high rates of sulfate reduction, but only the sediments within the Bay of Concepción contained dissolved sulfide. Due to advection and/or in-situ reoxidation of sulfide, dissolved sulfate was close to bottom water values. Whereas the concentrations of sulfite and thiosulfate were mostly in the submicromolar range, elemental sulfur was by far the dominant sulfur intermediate. Although the large nitrate- and sulfur-storing bacteria Thioploca were abundant, the major part of S0 was located extracellularly. The distribution of sulfur species and dissolved iron suggests the reaction of sulfide with FeOOH as an important pathway for sulfide oxidation and sulfur intermediate formation. This is in agreement with the sulfur isotope composition of co-existing elemental sulfur and iron monosulfides. In the Bay of Concepción, sulfur isotope data suggest that pyrite formation proceeds via the reaction of FeS with polysulfides or H2S. At the shelf stations, on the other hand, pyrite was significantly depleted in 34S relative to its potential precursors FeS and S0. Isotope mass balance considerations suggest further that pyritization at depth includes light sulfide, potentially originating from bacterial sulfur disproportionation. The ?34S-values of pyrite down to -38‰ vs. V-CDT are among the lightest found in organic-rich marine sediments. Seasonal variations in the sulfur isotope composition of dissolved sulfate indicated a dynamic non-steady-state sulfur cycle in the surface sediments. The 18O content of porewater sulfate increased with depth at all sites compared to the bottom water composition due to intracellular isotope exchange reactions during microbial sulfur transformations.

Zopfi, Jakob; JØrgensen, Bo Barker

2007-01-01

267

Biogeochemistry of sulfur and iron in Thioploca-colonized surface sediments in the upwelling area off central Chile.  

DEFF Research Database (Denmark)

The biogeochemistry of sedimentary sulfur was investigated on the continental shelf off central Chile at water depths between 24 and 88 m under partial influence of an oxygen minimum zone. Dissolved and solid iron and sulfur species, including the sulfur intermediates sulfite, thiosulfate, and elemental sulfur, were analyzed at high resolution in the top 20 cm. All stations were characterized by high rates of sulfate reduction, but only the sediments within the Bay of Concepción contained dissolved sulfide. Due to advection and/or in-situ reoxidation of sulfide, dissolved sulfate was close to bottom water values. Whereas the concentrations of sulfite and thiosulfate were mostly in the submicromolar range, elemental sulfur was by far the dominant sulfur intermediate. Although the large nitrate- and sulfur-storing bacteria Thioploca were abundant, the major part of S0 was located extracellularly. The distribution of sulfur species and dissolved iron suggests the reaction of sulfide with FeOOH as an important pathway for sulfide oxidation and sulfur intermediate formation. This is in agreement with the sulfur isotope composition of co-existing elemental sulfur and iron monosulfides. In the Bay of Concepción, sulfur isotope data suggest that pyrite formation proceeds via the reaction of FeS with polysulfides or H2S. At the shelf stations, on the other hand, pyrite was significantly depleted in 34S relative to its potential precursors FeS and S0. Isotope mass balance considerations suggest further that pyritization at depth includes light sulfide, potentially originating from bacterial sulfur disproportionation. The ?34S-values of pyrite down to -38‰ vs. V-CDT are among the lightest found in organic-rich marine sediments. Seasonal variations in the sulfur isotope composition of dissolved sulfate indicated a dynamic non-steady-state sulfur cycle in the surface sediments. The 18O content of porewater sulfate increased with depth at all sites compared to the bottom water composition due to intracellular isotope exchange reactions during microbial sulfur transformations.

Zopfi, Jakob; Michael E., Böttcher

2008-01-01

268

Isolation, characterization and optimization of indigenous acetic acid bacteria and evaluation of their preservation methods  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Background and Objectives: Acetic acid bacteria (AAB) are useful in industrial production of vinegar. The present study aims at isolation and identification of acetic acid bacteria with characterization, optimization, and evaluation of their acetic acid productivity."nMaterials and Methods: Samples from various fruits were screened for presence of acetic acid bacteria on glucose, yeast extract, calcium carbonate (GYC) medium. Carr medium supplemented with bromocresol green was used for distin...

Beheshti-maal, K.; Rasooli, I.; Sm, Sharafi

2010-01-01

269

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

270

Bacterial viability and antibiotic susceptibility testing with SYTOX green nucleic acid stain.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A fluorescent nucleic acid stain that does not penetrate living cells was used to assess the integrity of the plasma membranes of bacteria. SYTOX Green nucleic acid stain is an unsymmetrical cyanine dye with three positive charges that is completely excluded from live eukaryotic and prokaryotic cells. Binding of SYTOX Green stain to nucleic acids resulted in a > 500-fold enhancement in fluorescence emission (absorption and emission maxima at 502 and 523 nm, respectively), rendering bacteria w...

Roth, B. L.; Poot, M.; Yue, S. T.; Millard, P. J.

1997-01-01

271

Green’s Symmetries in Finite Digraphs  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The semigroup DV of digraphs on a set V of n labeled vertices is defined. It is shown that DV is faithfully represented by the semigroup Bn of n ´ n Boolean matrices and that the Green’s L, R, H, and D equivalence classifications of digraphs in DV follow directly from the Green’s classifications already established for Bn. The new results found from this are: (i) L, R, and H equivalent digraphs contain sets of vertices with identical neighborhoods which remain invariant under certain one...

Parks, Allen D.

2011-01-01

272

Sulfur and sulfides in chondrules  

Science.gov (United States)

The nature and distribution of sulfides within type I PO, POP and PP chondrules of the carbonaceous chondrite Vigarano (CV3) have been studied by secondary electron microscopy and electron microprobe. They occur predominantly as spheroidal blebs composed entirely of low-Ni iron sulfide (troilite, FeS) or troilite + magnetite but in less abundance in association with metallic Fe-Ni beads in opaque assemblages. Troilites are mainly located within the low-Ca pyroxene outer zone and their amounts increase with the abundance of low-Ca pyroxene within chondrules, suggesting co-crystallization of troilite and low-Ca pyroxene during high-temperature events. We show that sulfur concentration and sulfide occurrence in chondrules obey high temperature sulfur solubility and saturation laws. Depending on the fS2 and fO2 of the surrounding gas and on the melt composition, mainly the FeO content, sulfur dissolved in chondrule melts may eventually reach a concentration limit, the sulfur content at sulfide saturation (SCSS), at which an immiscible iron sulfide liquid separates from the silicate melt. The occurrence of both a silicate melt and an immiscible iron sulfide liquid is further supported by the non-wetting behavior of sulfides on silicate phases in chondrules due to the high interfacial tension between their precursor iron-sulfide liquid droplets and the surrounding silicate melt during the high temperature chondrule-forming event. The evolution of chondrule melts from PO to PP towards more silicic compositions, very likely due to high PSiO(g) of the surrounding nebular gas, induces saturation of FeS at much lower S content in PP than in PO chondrules, leading to the co-crystallization of iron sulfides and low-Ca pyroxenes. Conditions of co-saturation of low-Ca pyroxene and FeS are only achieved in non canonical environments characterized by high partial pressures of sulfur and SiO and redox conditions more oxidizing than IW-3. Fe and S mass balance calculations also suggest the occurrence of an external source of iron, very likely gaseous, during chondrule formation. We therefore propose that enrichments in sulfur (and other volatile and moderately volatile elements) from PO to PP type I bulk chondrule compositions towards chondritic values result from progressive reaction between partially depleted olivine-bearing precursors and a volatile-rich gas phase.

Marrocchi, Yves; Libourel, Guy

2013-10-01

273

Freeze-drying of lactic acid bacteria.  

Science.gov (United States)

Lactic acid bacteria are of great importance for the food and biotechnology industry. They are widely used as starters for manufacturing food (e.g., yogurt, cheese, fermented meats, and vegetables) and probiotic products, as well as for green chemistry applications. Freeze-drying or lyophilization is a convenient method for preservation of bacteria. By reducing water activity to values below 0.2, it allows long-term storage and low-cost distribution at suprazero temperatures, while minimizing losses in viability and functionality. Stabilization of bacteria via freeze-drying starts with the addition of a protectant solution to the bacterial suspension. Freeze-drying includes three steps, namely, (1) freezing of the concentrated and protected cell suspension, (2) primary drying to remove ice by sublimation, and (3) secondary drying to remove unfrozen water by desorption. In this chapter we describe a method for freeze-drying of lactic acid bacteria at a pilot scale, thus allowing control of the process parameters for maximal survival and functionality recovery. PMID:25428024

Fonseca, Fernanda; Cenard, Stéphanie; Passot, Stéphanie

2015-01-01

274

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

275

Photoproduction of hydrogen by membranes of green photosynthetic bacteria  

Energy Technology Data Exchange (ETDEWEB)

Photoproduction of H/sub 2/ from ascorbate by unit-membrane vesicles from Chlorobium limicola f. thiosulfatophilum was achieved with a system containing gramicidin D, tetramethyl-p-phenylenediamine, methyl viologen, dithioerythritol, Clostridium hydrogenase, and an oxygen-scavenging mixture of glucose, glucose oxidase, ethanol, and catalase. Maximum quantum yield was less than one percent. Half maximum rate of H/sub 2/ production occurred at a white-light intensity of approximately 0.15 cm/sup -2/. The reaction was inhibited completely by 0.3% sodium dodecylbenzene sulfonate, 1% Triton X-100, or preheating the vesicles at 100/sup 0/C for 5 minutes. Low concentrations (0.01 and 0.05%) of Triton X-100 about doubled the reaction rate.

Bernstein, J D; Olson, J M

1980-01-01

276

Mixed sulfur-iron particles packed reactor for simultaneous advanced removal of nitrogen and phosphorus from secondary effluent.  

Science.gov (United States)

A mixed sulfur-iron particles packed reactor (SFe reactor) was developed to simultaneously remove total nitrogen (TN) and total phosphorus (TP) of the secondary effluent from municipal wastewater treatment plants. Low effluent TN (SFe reactor than that [1.58 g N/(L·d)] of sulfur alone packed reactor due to the mutual enhancement between sulfur-based autotrophic denitrification and iron-based chemical denitrification. A high TP removal obtained in SFe reactor was attributed to chemical precipitation of iron particles. Microbial community analysis based on 16S rRNA revealed that autotrophic denitrifying bacteria Thiobacillus and Sulfuricella were the dominant genus, indicating that autotrophic denitrification played important role in nitrate removal. These results indicate that sulfur and iron particles can be packed together in a single reactor to effectively remove nitrate and phosphorus. PMID:25077656

Wang, Shenghui; Liang, Peng; Wu, Zhongqin; Su, Fengfeng; Yuan, Lulu; Sun, Yanmei; Wu, Qing; Huang, Xia

2015-01-01

277

First evidence for the presence of a hydrogenase in the sulfur-reducing bacterium Desulfuromonas acetoxidans.  

Science.gov (United States)

Hydrogenases, which are ubiquitous in sulfate-reducing bacteria, were previously thought to be absent from Desulfuromonas acetoxidans. For the first time, a hydrogenase from the strict anaerobic sulfur-respiring bacterium D. acetoxidans, grown on ethanol-malate, was detected and enriched. To assay the role of the hydrogenase in the energetic metabolism of D. acetoxidans, we examined the reactivity of the enzyme with polyheme cytochromes from the same bacterium. PMID:10464227

Brugna, M; Nitschke, W; Toci, R; Bruschi, M; Giudici-Orticoni, M T

1999-09-01

278

First Evidence for the Presence of a Hydrogenase in the Sulfur-Reducing Bacterium Desulfuromonas acetoxidans  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Hydrogenases, which are ubiquitous in sulfate-reducing bacteria, were previously thought to be absent from Desulfuromonas acetoxidans. For the first time, a hydrogenase from the strict anaerobic sulfur-respiring bacterium D. acetoxidans, grown on ethanol-malate, was detected and enriched. To assay the role of the hydrogenase in the energetic metabolism of D. acetoxidans, we examined the reactivity of the enzyme with polyheme cytochromes from the same bacterium.

Brugna, Marianne; Nitschke, Wolfgang; Toci, Rene?; Bruschi, Mireille; Giudici-orticoni, Marie-the?re?se

1999-01-01

279

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

280

Bacterial Disproportionation of Elemental Sulfur Coupled to Chemical Reduction of Iron or Manganese  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A new chemolithotrophic bacterial metabolism was discovered in anaerobic marine enrichment cultures. Cultures in defined medium with elemental sulfur (S0) and amorphous ferric hydroxide (FeOOH) as sole substrates showed intense formation of sulfate. Furthermore, precipitation of ferrous sulfide and pyrite was observed. The transformations were accompanied by growth of slightly curved, rod-shaped bacteria. The quantification of the products revealed that S0 was microbially disproportionated to...

Thamdrup, Bo; Finster, Kai; Hansen, Jens Wu?rgler; Bak, Friedhelm

1993-01-01

 
 
 
 
281

Transporters in plant sulfur metabolism.  

Science.gov (United States)

Sulfur is an essential nutrient, necessary for synthesis of many metabolites. The uptake of sulfate, primary and secondary assimilation, the biosynthesis, storage, and final utilization of sulfur (S) containing compounds requires a lot of movement between organs, cells, and organelles. Efficient transport systems of S-containing compounds across the internal barriers or the plasma membrane and organellar membranes are therefore required. Here, we review a current state of knowledge of the transport of a range of S-containing metabolites within and between the cells as well as of their long distance transport. An improved understanding of mechanisms and regulation of transport will facilitate successful engineering of the respective pathways, to improve the plant yield, biotic interaction and nutritional properties of crops. PMID:25250037

Gigolashvili, Tamara; Kopriva, Stanislav

2014-01-01

282

Geochemical and sulfur isotope signatures of microbial activity in acidic and sulfuric hot springs, northern Taiwan  

Science.gov (United States)

Acidic and sulfuric hot springs are natural habitats for thermophilic sulfur-utilizing microorganisms. Integration of bioenergetic evaluation, molecular analysis and stable isotopic signatures may be able to exhibit a full view of microbial activity in such an extreme environment. Widely distributed hot springs hosted by the Tatung volcano group in northern Taiwan provide a chance to evaluate the interplay between geochemical variation and microbial metabolism especially for sulfur. Several hot spring ponds varying in sizes and geochemical characteristics were studied to reveal the possible control of fluid compositions on microbial metabolisms, and vice versa. Sulfate, sulfide, elemental sulfur and dissolved organic carbon were available in spring water and sediments in the ponds. Dominant microbial metabolisms inferred from the bioenergetic evaluation were aerobic oxidations of various reduced compounds, including elemental sulfur, pyrite, ferrous iron and organic carbon. Sulfate and sulfur reductions were thermodynamically favorable but provided less energy flux, while sulfur disproportionation was thermodynamically incapable. The analyses of 16S rRNA genes extracted from the spring water and sediments indicated that aerobic oxidation of sulfur, hydrogen or organic carbon and anaerobic elemental sulfur reduction were possible metabolisms. Since the major portion of 16S rRNA sequences were affiliated with unclassified environmental sequences, their potential metabolisms remained obscure. Sulfur isotopic compositions of dissolved sulfate, pyrite and elemental sulfur exhibited significant variations among the different hot spring ponds. Apparently, the microbial effects on the sulfur isotopic signatures were various. A disproportionation reaction of volcanic gas was required to account for high sulfur isotope difference between sulfate and reduced sulfur in the large hot ponds. In contrary, abiotic or microbial oxidation of reduced sulfur might be dominant in the small ponds, where only small sulfur isotopic fractionation occurred among the sulfur species. Both sulfate and elemental sulfur reduction could not be recognized as the sulfide in all ponds were not the most depleted in S-34.

Wang, P.; Chen, K.; Cheng, T.; Hsieh, H.; Lin, L.

2009-12-01

283

Mechanistic modeling of sulfur-deprived photosynthesis and hydrogen production in suspensions of Chlamydomonas reinhardtii  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The ability of unicellular green algal species such as Chlamydomonas reinhardtii to produce hydrogen gas via iron-hydrogenase is well known. However, the oxygen-sensitive hydrogenase is closely linked to the photosynthetic chain in such a way that hydrogen and oxygen production need to be separated temporally for sustained photo-production. Under illumination, sulfur-deprivation has been shown to accommodate the production of hydrogen gas by partially-deactivating O2 evolution activity, leadi...

Williams, C. R.; Bees, M. A.

2014-01-01

284

Sulfur dioxide molecule sensors based on zigzag graphene nanoribbons with and without Cr dopant  

International Nuclear Information System (INIS)

Structure, electronic, and transport properties of sulfur dioxide (SO2) molecule adsorbed on pure and Cr doped zigzag graphene nanoribbons (ZGNRs) are investigated by means of first principle density functional theory and nonequilibrium Green's function computations. It is found that Cr doped ZGNR is more sensitive to SO2 molecule than pure ZGNR. The pure ZGNRs with and without SO2 molecule show similar I–V curves, but the current of Cr doped ZGNR will significant increase after SO2 molecule adsorption.

285

Evaluation the Amount of Emission and Sulfur Dioxide Emission Factor from Tehran Oil Refinery  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Bachgrounds and Objectives: Oil, gas and petrochemical are known as important sources of air pollutants and emission of green house gases. About 99 percent of sulfur dioxide in the air is produced from human resources. Although several samples have been taken from industries and refineries' output by environmental experts and private companies, but accurate assessment is not available based on pollutant emissions on product levels (emission coefficients) and on the total amount of the annual ...

Chavoshi B.; Massoudinjad M.R.; Adibzadeh A

2011-01-01

286

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.

287

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

288

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

289

Bacteria and Foodborne Illness  

Science.gov (United States)

... foodborne illnesses may lead to chronic disorders, including reactive arthritis, a type of joint inflammation that usually affects ... by certain bacteria, including C. jejuni and Salmonella . Reactive arthritis usually lasts fewer than 6 months, but this ...

290

Effect of sulfur-containing compounds on anaerobic degradation of cellulose to methane by mixed cultures obtained from sewage sludge  

Energy Technology Data Exchange (ETDEWEB)

Tests were made to determine the effects of inorganic and organic sulfur sources on the degradation of cellulose to methane in a chemically defined medium with sulfur-poor inoculum prepared from sewage sludge. The results show that a sulfur source of about a 0.85 mM concentration is essential for the degradation of cellulose to CH/sub 4/. However, the production of CH/sub 4/ from CO/sub 2/ and H/sub 2/ provided in the headspace occurred with 0.1 mM sulfate or sulfide. At a 9 mM concentration, all inorganic sulfur compounds other than sulfate inhibited both cellulose degradation and methane formation, and this inhibition increased in the order thiosulfate < sulfite < sulfide < H/sub 2/S. It appears that the degradation of cellulose to CH/sub 4/ in a sulfate-free medium by inoculum maintained in a low-sulfur medium is inhibited because of the lack of availability of sulfur for growth of bacteria and synthesis of cell materials and sulfur-containing cofactors involved in cellulose degradation and methanogenesis. The reduction of methanogenesis by higher levels of sulfate probably occurs as a result of stimulation of reactions converting acetate and H/sub 2/ to end products other than CH/sub 4/.

Khan, A.W.; Trotter, T.M.

1978-06-01

291

Effect of sulfur-containing compounds on anaerobic degradation of cellulose to methane by mixed cultures obtained from sewage sludge.  

Science.gov (United States)

Tests were made to determine the effects of inorganic and organic sulfur sources on the degradation of cellulose to methane in a chemically defined medium with sulfur-poor inoculum prepared from sewage sludge. The results show that a sulfur source of about a 0.85 mM concentration is essential for the degradation of cellulose to CH4. However, the production of CH4 from CO2 and H2 provided in the headspace occurred with 0.1 mM sulfate or sulfide. At a 9 mM concentration, all inorganic sulfur compounds other than sulfate inhibited both cellulose degradation and methane formation, and this inhibition increased in the order thiosulfate less than sulfite less than sulfide less than H2S. It appears that the degradation of cellulose to CH4 in a sulfate-free medium by inoculum maintained in a low-sulfur medium is inhibited because of the lack of availability of sulfur for growth of bacteria and synthesis of cell materials and sulfur-containing cofactors involved in cellulose degradation and methanogenesis. The reduction of methanogenesis by higher levels of sulfate probably occurs as a result of stimulation of reactions converting acetate and H2 to end products other than CH4. PMID:677869

Khan, A W; Trottier, T M

1978-01-01

292

LIGHTWEIGHT GREEN ROOF SYSTEMS  

Science.gov (United States)

Applying a Lightweight Green Roof System to a building can achieve in managing storm water runoff, decreasing heat gain, yielding energy savings, and mitigating the heat island effect. Currently, Most green roof systems are considerably heavy and require structural reinforceme...

293

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.

2007-01-01

294

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

Science.gov (United States)

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. PMID:21833324

Beard, Simón; Paradela, Alberto; Albar, Juan P; Jerez, Carlos A

2011-01-01

295

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

296

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)

297

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

298

The Green Man  

Science.gov (United States)

The Jolly Green Giant. Robin Hood. The Bamberg Cathedral. Tales of King Arthur. Ecology. What do they have in common? What legends and ancient myths are shrouded in the tales of the Green Man? Most often perceived as an ancient Celtic symbol as the god of spring and summer, the Green Man disappears and returns year after year, century after…

Watson-Newlin, Karen

2010-01-01

299

Relationship between the occurrence of filamentous bacteria on Bathymodiolus azoricus shell and the physiological and toxicological status of the vent mussel  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The edifice walls of the Eiffel Tower hydrothermal vent site (Mid-Atlantic Ridge, Lucky Strike vent field) are populated with dense communities of dual symbioses harboring vent mussel Bathymodiolus azoricus, some of which are covered by white filamentous mats belonging to sulfur-oxidizing bacteria. Mussels were collected in both the presence and absence of the filamentous bacteria. A sample of the filamentous bacteria was collected and water measurements of temperature, CH4 and H2S were recor...

Martins, I.; Colaco, A.; Santos, Raphael; Lesongeur, Francoise; Godfroy, Anne; Sarradin, Pierre-marie; Cosson, R. P.

2009-01-01

300

Microbial Sulfur Geochemistry in Mine Systems (Invited)  

Science.gov (United States)

Acid mine drainage (AMD), metal laden, acidic water, is the most pressing mining environmental issue on a global scale. While it is well recognized that the activity of autotrophic Fe and S bacteria amplify the oxidation of the sulfidic wastes, thereby generating acidity and leaching metals; the underlying microbial geochemistry is not well described. This talk will highlight results revealing the importance of microbial cooperation associated with a novel sulfur-metabolizing consortium enriched from mine waters. Results generated by an integrated approach, combining field characterization, geochemical experimentation, scanning transmission X-ray microscopy (STXM), and fluorescence in situ hybridization (FISH) [1]describing the underlying ecological drivers, the functionally relevant biogeochemical architecture of the consortial macrostructure as well as the identities of this environmental sulphur redox cycling consortium will be presented. The two common mine bacterial strains involved in this consortium, Acidithiobacillus ferroxidans and Acidiphilium sp., are specifically spatially segregated within a macrostructure (pod) of extracellular polymeric substance (EPS) that enables coupled sulphur oxidation and reduction reactions despite bulk, oxygenated conditions. Identical pod formation by type culture strains was induced and linked to ecological conditions. The proposed sulphur geochemistry associated with this bacterial consortium produces 40-90% less acid than expected based on abiotic AMD models, with implications for both AMD mitigation and AMD carbon flux modeling. We are currently investigating the implications of these sulphur-processing pods for metal dynamics in mine systems. These results demonstrate how microbes can orchestrate their geochemical environment to facilitate metabolism, and underscore the need to consider microbial interactions and ecology in constraining their geochemical impacts. [1] Norlund, Southam, Tyliszcczak, Hu, Karunakaran, Obst, Hitchcock &Warren (2009) Environmental Science & Technology 43, 8781-8786.

Warren, L. A.; Norlund, K. L.; Hitchcock, A.

2010-12-01

 
 
 
 
301

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

302

Green Transformational Leadership and Green Performance: The Mediation Effects of Green Mindfulness and Green Self-Efficacy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

No prior literature explores the influence of green transformational leadership on green performance, thus, this study develops a novel research framework to fill the research gap. This study investigates the influence of green transformational leadership on green performance and discusses the mediation effects of green mindfulness and green self-efficacy by means of structural equation modeling (SEM). The results indicate that green transformational leadership positively influences green min...

Yu-Shan Chen; Ching-Hsun Chang; Yu-Hsien Lin

2014-01-01

303

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

304

Oxidative stress enhances the expression of sulfur assimilation genes: preliminary insights on the Enterococcus faecalis iron-sulfur cluster machinery regulation.  

Science.gov (United States)

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 inorganic prosthetic groups involved in diverse biological processes, whose in vivo formation requires several specific protein machineries. Escherichia coli is one of the most frequently studied microorganisms regarding [Fe-S] cluster biogenesis and encodes the iron-sulfur cluster and sulfur assimilation systems. In Firmicutes species, a unique operon composed of the sufCDSUB genes is responsible for [Fe-S] cluster biogenesis. The aim of this study was to investigate the potential of the E. faecalis sufCDSUB system in the [Fe-S] cluster assembly using oxidative stress and iron depletion as adverse growth conditions. Quantitative real-time polymerase chain reaction demonstrated, for the first time, that Gram-positive bacteria possess an OxyR component responsive to oxidative stress conditions, as fully described for E. coli models. Likewise, strong expression of the sufCDSUB genes was observed in low concentrations of hydrogen peroxide, indicating that the lowest concentration of oxygen free radicals inside cells, known to be highly damaging to [Fe-S] clusters, is sufficient to trigger the transcriptional machinery for prompt replacement of [Fe-S] clusters. PMID:24936909

Riboldi, Gustavo Pelicioli; Bierhals, Christine Garcia; de Mattos, Eduardo Preusser; Frazzon, Ana Paula Guedes; d'Azevedo, Pedro Alves; Frazzon, Jeverson

2014-07-01

305

Assimilatory sulfur metabolism in marine microorganisms: sulfur metabolism, protein synthesis, and growth of Alteromonas luteo - violaceus and Pseudomonas halodurans during perturbed batch growth  

Energy Technology Data Exchange (ETDEWEB)

The antibiotic protein synthesis inhibitor chloramphenicol specifically blocked the incorporation of (35 S) sulfate into the residue protein of two marine bacteria, Pseudomonas halodurans and Alteromonas luteo-violaceus. Simultaneous inhibition of total protein synthesis occurred, but incorporation of 35 S into low-molecular-weight organic compounds continued. A. luteo-violaceus rapidly autolyzed, with similar reduction in cell counts, total culture protein and cellular sulfur, whereas P. halodurans remained viable. Treatment with chloramphenicol, growth during nitrogen and carbon limitation, and the carbon and energy sources used for growth did not alter the sulfur content of P. halodurans protein. The mean value (1.09%, by weight), representing a wide variety of environmentally relevant growth conditions, was in agreement with model protein composition. The variability of cellular composition of P. halodurnas and A. luteo-violaceus is discussed with respect to the measurement of bacterial growth in natural environments. Total carbon and nitrogen per cell varied greatly (coefficient of variation, ca. 100%) depending on growth conditions. Variation in total sulfur and protein per cell was much less (coefficient of variation, less than 50%), but the least variation was found for sulfate incorporation into residue protein (coefficient of variation, ca. 15%). Thus, sulfate incorporation into residue protein can be used as an accurate measurement of de novo protein synthesis in these bacteria. (Refs. 26).

Cuhel, R.L.; Taylor, C.D.; Jannasch, H.W.

1982-01-01

306

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 diverse biological processes, whose in vivo formation requires several specific protein machineries. Escherichia coli is one of the most frequently studied microorganisms regarding [Fe-S] cluster biogenesis and encodes the iron-sulfur cluster and sulfur assimilation systems. In Firmicutes species, a unique operon composed of the sufCDSUB genes is responsible for [Fe-S] cluster biogenesis. The aim of this study was to investigate the potential of the E. faecalis sufCDSUB system in the [Fe-S] cluster assembly using oxidative stress and iron depletion as adverse growth conditions. Quantitative real-time polymerase chain reaction demonstrated, for the first time, that Gram-positive bacteria possess an OxyR component responsive to oxidative stress conditions, as fully described for E. coli models. Likewise, strong expression of the sufCDSUB genes was observed in low concentrations of hydrogen peroxide, indicating that the lowest concentration of oxygen free radicals inside cells, known to be highly damaging to [Fe-S] clusters, is sufficient to trigger the transcriptional machinery for prompt replacement of [Fe-S] clusters.

Gustavo Pelicioli, Riboldi; Christine Garcia, Bierhals; Eduardo Preusser de, Mattos; Ana Paula Guedes, Frazzon; Pedro Alves, d?Azevedo; Jeverson, Frazzon.

2014-07-01

307

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 diverse biological processes, whose in vivo formation requires several specific protein machineries. Escherichia coli is one of the most frequently studied microorganisms regarding [Fe-S] cluster biogenesis and encodes the iron-sulfur cluster and sulfur assimilation systems. In Firmicutes species, a unique operon composed of the sufCDSUB genes is responsible for [Fe-S] cluster biogenesis. The aim of this study was to investigate the potential of the E. faecalis sufCDSUB system in the [Fe-S] cluster assembly using oxidative stress and iron depletion as adverse growth conditions. Quantitative real-time polymerase chain reaction demonstrated, for the first time, that Gram-positive bacteria possess an OxyR component responsive to oxidative stress conditions, as fully described for E. coli models. Likewise, strong expression of the sufCDSUB genes was observed in low concentrations of hydrogen peroxide, indicating that the lowest concentration of oxygen free radicals inside cells, known to be highly damaging to [Fe-S] clusters, is sufficient to trigger the transcriptional machinery for prompt replacement of [Fe-S] clusters.

Gustavo Pelicioli, Riboldi; Christine Garcia, Bierhals; Eduardo Preusser de, Mattos; Ana Paula Guedes, Frazzon; Pedro Alves, d?Azevedo; Jeverson, Frazzon.

2014-06-06

308

SULFUR COMPOUNDS IN PETROLEUM HYDROCARBON STREAMS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Determination of concentrations of sulfur compounds in different petroleum samples is a true analytical challenge. Only analytical procedures based on gas chromatography can meet the sensitivity and accuracy requirements dictated by up-to-date petroleum industry.The objective of this work is to develop the method for the quantifying of sulfur compounds in petroleum hydrocarbon streams. The optimum parameters for the GC-SCD method are found in order to determine of sulfur compounds in petroleu...

Antoaneta Pavlova; Pavlina Ivanova; Teodora Dimova

2012-01-01

309

Reduced sulfur compound oxidation by Thiobacillus caldus.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The oxidation of reduced inorganic sulfur compounds was studied by using resting cells of the moderate thermophile Thiobacillus caldus strain KU. The oxygen consumption rate and total oxygen consumed were determined for the reduced sulfur compounds thiosulfate, tetrathionate, sulfur, sulfide, and sulfite in the absence and in the presence of inhibitors and uncouplers. The uncouplers 2,4-dinitrophenol and carbonyl cyanide m-chlorophenyl-hydrazone had no affect on the oxidation of thiosulfate, ...

Hallberg, K. B.; Dopson, M.; Lindstro?m, E. B.

1996-01-01

310

Sulfur Resistance of Pt-W Catalysts  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The sulfur resistance of low-loaded monometallic Pt catalysts and bimetallic Pt-W catalysts during the partial selective hydrogenation of styrene, a model compound of Pygas streams, was studied. The effect of metal impregnation sequence on the activity and selectivity was also evaluated. Catalysts were characterized by ICP, TPR, XRD, and XPS techniques. Catalytic tests with sulfur-free and sulfur-doped feeds were performed. All catalysts showed high selectivities (>98%) to ethylbenzene. Activ...

Betti, Carolina P.; Badano, Juan M.; Rivas, Ivana L.; Mazzieri, Vanina A.; Juliana Maccarrone, M.; Fernando Coloma-Pascual; Vera, Carlos R.; Quiroga, M. Amp Xf Nica E.

2013-01-01

311

Thiophenic Sulfur Compounds Released During Coal Pyrolysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Thiophenic sulfur compounds are released during coal gasification, carbonization, and combustion. Previous studies indicate that thiophenic sulfur compounds degrade very slowly in the environment, and are more carcinogenic than polycyclic aromatic hydrocarbons and nitrogenous compounds. Therefore, it is very important to study the principle of thiophenic sulfur compounds during coal conversion, in order to control their emission and promote clean coal utilization. To realize this goal and und...

Xing, Mengwen; Kong, Jiao; Dong, Jie; Jiao, Haili; Li, Fan

2013-01-01

312

Sulfur Production by Obligately Chemolithoautotrophic Thiobacillus Species  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Transient-state experiments with the obligately autotrophic Thiobacillus sp. strain W5 revealed that sulfide oxidation proceeds in two physiological phases, (i) the sulfate-producing phase and (ii) the sulfur- and sulfate-producing phase, after which sulfide toxicity occurs. Specific sulfur-producing characteristics were independent of the growth rate. Sulfur formation was shown to occur when the maximum oxidative capacity of the culture was approached. In order to be able to oxidize increasi...

Visser, J. M.; Robertson, L. A.; Varseveld, H. W.; Kuenen, J. G.

1997-01-01

313

COS degradation by selected CO-utilizing bacteria  

Energy Technology Data Exchange (ETDEWEB)

Synthesis gas, a major product of coal gasification, typically contains 1-2 sulfur by volume, with 95-99% or more of the sulfur present as H{sub 2}S. Typical levels of carbonyl sulfide (COS) in coal-derived synthesis gas range from 0.03-0.07% by volume, although COS concentrations have been observed in the 5-10% range. Although COS is present in only small quantities, it poses serious problems to equipment and the environment. COS is corrosive to both iron and steel, and is a precursor to the formation of sulfur oxide derivatives, which are highly regulated environmental pollutants. COS also poses significant problems to downstream catalysts as a catalyst poison. Examples of catalysts for downstream processing of synthesis gas to methane include nickel and potassium-based catalysts, as well as mixtures of iron/chromium oxides and zinc/copper oxides. Poisons for these catalysts include chlorine and sulfur. This report describes the degradation of COS by carbon monoxide utilizing bacteria.

Smith, K.D.; Klasson, K.T.; Ackerson, M.D.; Clausen, E.C.; Gaddy, J.L. [Univ. of Arkansas, Fayetteville, AR (United States)

1991-12-31

314

Mobility of sulfur in thermally altered meteorites  

Science.gov (United States)

Sulfur and volatile trace element (bismuth, cadmium, and thallium) mobility were studied in Allende (CV3) and Leedey (L6) chondrite samples heated for 1 to 168 hours, at 100 C increments, from 400 to 1000 C in a low pressure environment of hydrogen and oxygen. A vacuum system was constructed to heat samples in an open and closed environment. Three trace elements were determined by direct analysis of solids using electrothermal atomic absorption spectroscopy. Sulfur was determined by either iodometric titration or infrared absorption of sulfur dioxide expelled during inductive heating of samples in an oxygen environment. The sulfur gases released during the heating experiments were also analyzed by gas chromatography to better understand the mechanism of sulfur mobility. Sulfur is very mobile in a low pressure oxygen environment (10 exp -8 power atm) at 650 C. Sulfur is also mobilized in a low-pressure hydrogen environment (10 exp -5 power atm) at 650 C, but to a lesser extent. Ordinary chondrites have a constant sulfur content. They are depleted in sulfur by a factor of two compared to CI chondrites. The results are compared to earlier heating experiments completed by the Purdue group, J. Cripe and J. W. Larimer (1976) and E. K. Gibson, Jr. (1976). The loss of volatile trace elements from ordinary chondrites by simple open system metamorphism is not supported by the results obtained.

Primus, Thomas Michael

315

Determination of sulfur content in fuels  

International Nuclear Information System (INIS)

The sulfur content in fuels, Diesel fuels, and in the solutions of dibutylsulfide in a white oil was determined by various methods. The results obtained by elemental analysis have shown that the method is not advisable for the determination of sulfur in fuels. A good agreement was found by comparing the results in the determination of the sulfur by Grote-Krekeler's and Hermann-Moritz's methods and by the energy-dispersive X-ray fluorescence analysis. The last method is the modern, comfortable, and timesaving method enabling the fast and precise determination of sulfur contents in the various types of samples. (authors)

316

Sulfur use efficiency ofradish as affected by sulfur source and rate in typic ustifluvent soil  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Radish is one of the most popular root crops inthe tropical and temperate regions. Sulfurdeficiency is common in coarse textured soildue to leachingloss. Rootyieldof radishis reportedtoincreasewith sulfur application.Fieldexperiments was conducted in two seasons to study theeffect of sulfur(S) rate and sourceon radish (Raphanus sativus L.) nutrition, an experimentwas conducted in aPadugai sandy clay loam(TypicUstifluvents) deficient in available sulfur. The treatmentsconsisted of four levels ...

Sriramachandrasekharan, M. V.

2012-01-01

317

Binding mechanism of sulfur and dehydrogenated polyacrylonitrile in sulfur/polymer composite cathode  

Science.gov (United States)

A composite consisting of sulfur/dehydrogenated polyacrylonitrile is one of the most promising cathode materials for use in rechargeable lithium-sulfur batteries. However, the reported sulfur contents have been low, less than 50 wt%, which compromise the intrinsic high specific capacity and energy of elemental sulfur and hence decrease significantly the specific energy of the composite. To identify the potential to further increase the sulfur content, we elucidate the binding mechanism of sulfur and polyacrylonitrile in their composite. The heat treatment experiments at varying timespans with excess sulfur showed a constancy of sulfur content after a critical length of timespan, indicating the saturation of sulfur in the structure of dehydrogenated polyacrylonitrile. Based on molecular structure and size consideration, it is proposed that the binding involves the formation of an 8 membered ring of sulfur embedded between 4 heterocyclic rings of dehydrogenated polyacrylonitrile. From this model and experimental results, we show that there exists an upper limit of sulfur content in the sulfur/dehydrogenated polyacrylonitrile composite at 56 wt%.

Doan, The Nam Long; Ghaznavi, Mahmoudreza; Zhao, Yan; Zhang, Yongguang; Konarov, Aishuak; Sadhu, Mikhail; Tangirala, Ravichandra; Chen, P.

2013-11-01

318

Graphene-wrapped sulfur nanospheres with ultra-high sulfur loading for high energy density lithium-sulfur batteries  

Science.gov (United States)

Lithium-sulfur (Li-S) battery with high theoretical energy density is one of the most promising energy storage systems for electric vehicles and intermittent renewable energy. However, due to the poor conductivity of the active material, considerable weight of the electrode is occupied by the conductive additives. Here we report a graphene-wrapped sulfur nanospheres composite (S-nanosphere@G) with sulfur content up to 91 wt% as the high energy density cathode material for Li-S battery. The sulfur nanospheres with diameter of 400-500 nm are synthesized through a solution-based approach with the existence of polyvinylpyrrolidone (PVP). Then the sulfur nanospheres are uniformly wrapped by conductive graphene sheets through the electrostatic interaction between graphene oxide and PVP, followed by reducing of graphene oxide with hydrazine. The design of graphene wrapped sulfur nanoarchitecture provides flexible conductive graphene coating with void space to accommodate the volume expansion of sulfur and to minimize polysulfide dissolution. As a result, the S-nanosphere@G nanocomposite with 91 wt% sulfur shows a reversible initial capacity of 970 mA h g-1 and an average columbic efficiency > 96% over 100 cycles at a rate of 0.2 C. Taking the total mass of electrode into account, the S-nanosphere@G composite is a promising cathode material for high energy density Li-S batteries.

Liu, Ya; Guo, Jinxin; Zhang, Jun; Su, Qingmei; Du, Gaohui

2015-01-01

319

Reduced Sulfur in Ashes and Slags from the Gasification of Coals: Availability for Chemical and Microbial Oxidation †  

Science.gov (United States)

This study was initiated to determine if reduced sulfur contained in coal gasifier ash and slag was available for microbial and chemical oxidation because eventual large-quantity landfill disposal of these solid wastes is expected. Continuous application of distilled water to a column containing a high-sulfur-content (4% [wt/wt]) gasifier slag yielded leachates with high sulfate levels (1,300 mg of sulfate liter?1) and low pH values (4.2). At the end of the experiment, a three-tube most-probable-number analysis indicated that the waste contained 1.3 × 107 thiosulfate-oxidizing bacteria per g. Slag samples obtained aseptically from the column produced sulfate under both abiotic and biotic conditions when incubated in a mineral nutrient solution. Both microbial and chemical sulfate syntheses were greatly stimulated by the addition of thiosulfate to the slag-mineral nutrient solution. These results led to a test of microbial versus chemical sulfur oxidation in ashes and slags from five gasification processes. Sulfate production was measured in sterile (autoclaved) and nonsterile suspensions of the solid wastes in a mineral nutrient solution. These ashes and slags varied in sulfur content from 0.3 to 4.0% (wt/wt). Four of these wastes demonstrated both chemical (2.0 to 27 ?g of sulfate g?1 day?1) and microbial (3.1 to 114 ?g of sulfate g?1 day?1) sulfur oxidation. Obvious relationships between sulfur oxidation rate and either sulfur content or particle size distribution of the wastes were not immediately evident. We conclude that the sulfur contained in all but one waste is available for oxidation to sulfuric acid and that microorganisms play a partial role in this process. PMID:16346240

Strayer, Richard F.; Davis, Edward C.

1983-01-01

320

Sulfur-bridged BODIPY DYEmers.  

Science.gov (United States)

Reactions of BODIPY monomers with sulfur nucleophiles and electrophiles result in the formation of new BODIPY dimers. Mono- and disulfur bridges are established, and the new dyestuff molecules were studied with respect to their structural, optical, and electrochemical properties. X-ray diffraction analyses reveal individual angulated orientations of the BODIPY subunits in all cases. DFT calculations provide solution conformers of the DYEmers which deviate in a specific manner from the crystallographic results. Clear exciton-like splittings are observed in the absorption spectra, with maxima at up to 628?nm, in combination with the expected weak fluorescence in polar solvents. A strong communication between the BODIPY subunits was detected by cyclic voltammetry, where two separated one-electron oxidation and reduction waves with peak-to-peak potential differences of 120-400?mV are observed. The qualitative applicability of the exciton model by Kasha for the interpretation of the absorption spectral shape with respect to the conformational state, subunit orientation and distance, and conjugation through the different sulfur bridges, is discussed in detail for the new BODIPY derivatives. This work is part of our concept of DYEmers, where the covalent oligomerisation of BODIPY-type dye molecules with close distances is leading to new functional dyes with predictable properties. PMID:23843344

Ahrens, Johannes; Böker, Birte; Brandhorst, Kai; Funk, Markus; Bröring, Martin

2013-08-19

 
 
 
 
321

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

Science.gov (United States)

A long (20-30 micrometer), wide (3-5 micrometer) 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 than 10 body lengths per second. The large size of the spirillum permits direct observation of cell motility in single individual bacteria. After desiccation (i.e., absence of standing water for at least 24 h), large populations developed in mat samples remoistened with sea water. Ultrastructural observations reveal abundant large sulfur globules irregularly distributed in the cytoplasm. A multilayered cell wall, pliable and elastic yet rigid, distends around the sulfur globules. Details of the wall, multiflagellated termini, and large cytoplasmic sulfur globules indicate that these fast-moving spirilla are distinctive enough to warrant a genus and species designation: Titanospirillum velox genus nov., sp. nov. The same collection techniques at a similar habitat in the United States (Plum Island, northeast Essex County, Massachusetts) also yielded large populations of the bacterium among purple phototrophic and other inhabitants of sulfurous microbial-mat muds. The months-long survival of T. velox from Spain and from the United States in closed jars filled with mud taken from both localities leads us to infer that this large spirillum has a cosmopolitan distribution.

Guerrero, R.; Haselton, A.; Sole, M.; Wier, A.; Margulis, L.

1999-01-01

322

Green energy in Europe: selling green energy with green certificates  

International Nuclear Information System (INIS)

Sales of green power products are booming in Europe: 50,000 customers in the United Kingdom, 775,000 in the Netherlands and 300,000 in Germany. Laws of physics are however formal: the way in which electricity flows within the grid does not allow suppliers to assure customers that they are directly receiving electricity produced exclusively from renewable energy sources. What are marketers selling their customers then? Laetitia Ouillet, Greenprices, takes a closer look and focuses on the potential of selling green energy in the forms of renewable energy certificates. (Author)

323

The isotopic composition of sulfur and the genesis of mirabilite from the Miocene Oya formation, Tochigi Prefecture  

International Nuclear Information System (INIS)

The sulfur isotope ratios of mirabilite and gypsum from a pumice tuff formation of the Miocene ''green tuff'' group in Oya, Tochigi Prefecture, are remarkably light, being -16 to -20 in delta 34S per mil value relative to the meteoritic sulfur. Comparative isotopic values are observed for pyrites in the formation, which are considered to be of the syngenetic or diagenetic origin. The SO42- in the sulfate minerals is possibly derived from the near-surface oxidation of the biogenic sulfides. (Mori, K.)

324

Lithium-sulfur batteries: problems and solutions  

International Nuclear Information System (INIS)

Fundamental problems in the design of lithium-sulfur batteries, i.e. low practical specific energy, rapid decrease in capacity during cycling, and high self-discharge rates, are considered. It is demonstrated that the problems can be solved by the provision of an optimum combination of the rates of electrode and corrosion processes in lithium-sulfur batteries during cycling

325

Preparation of sulfur-35-labeled dimethyl sulfide  

International Nuclear Information System (INIS)

The authors study the preparation of sulfur-35 labeled dimethyl sulfide by isotope exchange between sulfur-35 labeled sodium sulfide and dimethyl sulfide in order to draw conclusions concerning the quantitative and kinetic characteristics of isotope exchange between them. Isotope exchange is shown to take place in aqueous dimethyl sulfide

326

Quenching of fluorescence by crystal violet and its use to differentiate between surface-bound and internalized bacteria  

Science.gov (United States)

Phagocytosis is a complex process involving attachment, ingestion and intracellular processing of bacteria by phagocytes. A great difficulty in the evaluation of this process is to differentiate between attachment of the particles to the cell surface and internalization of the particles by the cells. Various techniques have been used to differentiate internalized and surface-attached bacteria in cultured cells, but only a few permit differentiations between surface-bound and internalized bacteria. In this study the quenching of fluorescence by crystal violet on acridine orange stained bacterial biofilm and planktonic bacterial cells is used to differentiate between surface-bound and internalized bacteria within macrophages. Method: One week old Enterococcus faecalis biofilm was grown on perspex and glass substrates in All-Culture medium (nutrient-rich condition) and phosphate buffered saline (nutrient-deprived condition). As model systems, human monocytic (THP-1) and histiocytic (U937) cell lines were used. These cell lines were incubated with the biofilm bacteria for 4 hrs in CO II incubator at 37 °C. The cells and bacteria were stained with acridine orange and quenched with crystal violet to distinguish between surface-bound and internalized bacteria. Results: The presence of green-fluorescing internalized bacteria was detected within the macrophages under the planktonic, nutrient-rich and nutrient-deprived biofilm conditions. All infecting bacteria take up acridine orange and fluoresced green, crystal violet quenched the fluorescence of extra-cellular adhering bacteria so that only fluorescent intracellular bacteria would be visible under fluorescent light microscopy.

Mathew, S.; Lim, Y. C.; Kishen, A.

2008-06-01

327

Antibiotic-Resistant Bacteria.  

Science.gov (United States)

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

Longenecker, Nevin E.; Oppenheimer, Dan

1982-01-01

328

Immunity to intracellular bacteria  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Immunity to intracellular bacteria including Mycobacterium tuberculosis. Mycobacterium leprae, and Listeria monocytogenes depends on specific T cells. Evidence to be described suggests that CD4 (alpha/beta)T cells which interact with each other and with macrophages contribute to acquired resistence against as well as pathogenesis of intracellular bacterial infections.

Kaufmann, Stefan H. E.; Follows, George A.; Munik, Martin E.

1992-01-01

329

Immunity to intracellular bacteria  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Immunity to intracellular bacteria including Mycobacterium tuberculosis. Mycobacterium leprae, and Listeria monocytogenes depends on specific T cells. Evidence to be described suggests that CD4 (alpha/beta)T cells which interact with each other and with macrophages contribute to acquired resistence [...] against as well as pathogenesis of intracellular bacterial infections.

Stefan H. E., Kaufmann; George A., Follows; Martin E., Munik.

330

Immunity to intracellular bacteria  

Directory of Open Access Journals (Sweden)

Full Text Available Immunity to intracellular bacteria including Mycobacterium tuberculosis. Mycobacterium leprae, and Listeria monocytogenes depends on specific T cells. Evidence to be described suggests that CD4 (alpha/betaT cells which interact with each other and with macrophages contribute to acquired resistence against as well as pathogenesis of intracellular bacterial infections.

Stefan H. E. Kaufmann

1992-01-01

331

Green Office – ympäristöjärjestelmä  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The purpose of this thesis was to investigate WWF’s Green Office environmental pro-gramme and the possibilities of its implementation in companies of different sizes. The thesis studied different ecological purchases and changes in practice that would help in the implementation of the environmental programme and in acquiring the Green Office certificate. The theoretical part of the thesis discussed the following issues: the concept of Green Office and the guidelines for getting the rela...

Laine, Elina; Ramamurthy, Katriina

2013-01-01

332

What's Green Building?  

Science.gov (United States)

This presentation from green building consultant Dan Saddler provides an introduction to the basics of green building. "Green building" itself is defined, and the sustainability concepts involved are explored. The presentation is mostly visual but also contains some very useful statistics and graphical representations of data. Insulation techniques, sustainable building materials and methods, site protection and location and other related topics are covered. This document may be downloaded in PDF file format.

Saddler, Dan

333

Sulfur species in volcanic gases.  

Science.gov (United States)

A new analytical method for the determination of the sulfur species (SO2, H2S, S8(0)) in volcanic gases is proposed by revising, updating, and improving previous methods. The most significant advantages of the proposed procedure can briefly be summarized, as follows: (i) the reaction among sulfur species stops during the gas sampling by using preevacuated thorion-tapped vials with purified 0.15M Cd(OH)2 in 4 M NaOH to favor the precipitation of H2S as CdS; (ii) all the sulfur species (SO2, H2S, S8(0)) are analyzed by ion chromatography, after conversion to SO4, which allows the detection limit to be lowered significantly with respect to the previous studies; (iii) appropriate aliquots from intermediate steps may be used to determine other species commonly present in volcanic gases such as CO2, HCI, HF, HBr, HI, and so forth; (iv) determination of all the other gas species is not jeopardized by the proposed method, i.e., one single vial can be used for analyzing the full chemical composition of a volcanic gas with the exception of NH3. Statistical parameters calculated from gas sampling data at the F5 crater fumarole in Vulcano Island (Aeolian Islands, southern Italy), suggest that the standard error of mean (s/ root n) is higher for S (0.10), followed by SO2, H2S, and CO2 (0.04, 0.038, and 0.028, respectively). SO2 shows the higher variation coefficient (12.1%) followed by H2S, S, and CO2 (5.7, 1.5, and 0.8%, respectively). Furthermore, if the time dependence of sampling is taken into account, the measured values, instead of fluctuating in a random manner, tend to follow systematic patterns, out of statistical control, possibly suggesting a sort of natural fluctuation of the volcanic system. Other crater fumaroles from volcanic systems located in different geodynamical areas (Hawaii, USA, El Chichon, Mexico, Poas, Costa Rica) have been analyzed as well. PMID:11510838

Montegrossi, G; Tassi, F; Vaselli, O; Buccianti, A; Garofalo, K

2001-08-01

334

Decoupling the Impacts of Heterotrophy and Autotrophy on Sulfuric Acid Speleogenesis  

Science.gov (United States)

Within caves such as Movile Caves (Romania), the Frasassi Caves (Italy), and Lower Kane Cave (LKC, Wyoming, USA) the combination of abiotic autoxidation and microbiological oxidation of H2S produces SO42- and H+ that promotes limestone dissolution through sulfuric-acid speleogenesis (SAS). Microbial sulfide oxidation by sulfur-oxidizing bacteria (SOB) has been shown recently to be the dominant process leading to speleogenesis in these caves. However, due to the inherently large diversity of microbial communities within these environments, there are a variety of metabolic pathways that can impact limestone dissolution and carbon cycling to varying degrees. In order to investigate these variations we outfitted a continuous flow bioreactor with a Picarro Wavelength-Scanned Cavity Ring Down Spectrometer (WS-CRDS) that continuously monitored and logged 12CO2 and 13CO2 at ppmv sensitivity and isotope ratios at pH were also continuously logged in order to quantify the impact of microbial metabolism on limestone dissolution rate. We found an order of magnitude of variability in limestone dissolution rates that were closely tied to microbial metabolism. In monocultures, limestone dissolution was inhibited by excessive reduced sulfur as T. unzii prefers to store sulfur internally as So under these conditions, generating no acidity. The headspace was depleted in 13C when sulfur was being stored as So and enriched in 13C when sulfur was being converted to SO42-. This suggests a preference for a heterotrophy during periods of high sulfur input and autotrophy when sulfur input is low. This was corroborated by an increase in SO42- during low sulfide input and microscope images showed loss of internal sulfur within the filaments during these periods. In both monoculture and LKC environmental cultures, dissolution rates were highest when sulfur-substrate was limited and CO2 was supplied with no organic carbon. Under these conditions ?13C values were as much as 20‰ higher than abiotic conditions and signifies autotrophic carbon fixation which discriminates against 13C. 16S rRNA sequences confirm that autotrophic SOB dominate within this reactor. In contrast, when acetate was supplied with no supplied CO2, ?13C was relatively constant, maintaining values between -31‰ and as low as -37‰. This signifies heterotrophic metabolism where lighter 12C is preferentially consumed resulting in lighter CO2 in the headspace. 16S rRNA sequences confirm that heterotrophic sulfur-reducing bacteria dominate the community within this reactor. When both acetate and CO2 were supplied the heterotrophic behavior appeared to dominate the system which resulted in a significant drop (15‰) in ?13C and a correlative drop in limestone dissolution rate. These results suggest that chemoautotrophy increases the rate of SAS and CO2 flux within the cave environment while heterotrophy leads to slower SAS or even calcite precipitation. Furthermore, changes in carbon substrate (CO2 vs. Acetate) or sulfur substrate concentrations caused an immediate microbial response that could be observed in all measured chemical variables.

Jones, A. A.; Bennett, P.

2013-12-01

335

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

336

Luonnontuotteiden käyttö Green Care -toiminnassa  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Opinnäytetyöni aiheena on Luonnontuotteiden käyttö Green Care -toiminnassa. Toimeksiantaja työlleni on Green Care Lappi -hanke, jonka toimintaa hallinnoi Rovaniemen ammattikorkeakoulu. Green Care -toimintaa yleisesti koordinoi Green Care Finland ry. Opinnäytetyöni tarkoituksena on selvittää lappilaisten yritysten luonnontuotteiden käyttöä ja sitä, miten se on yhdistetty Green Care -toimintaan. Materiaalin opinnäytetyöhöni sain sähköpostikyselyllä, jossa selvitettiin muu...

Anttila, Emmi

2013-01-01

337

Coupled reductive and oxidative sulfur cycling in the phototrophic plate of a meromictic lake.  

Science.gov (United States)

Mahoney Lake represents an extreme meromictic model system and is a valuable site for examining the organisms and processes that sustain photic zone euxinia (PZE). A single population of purple sulfur bacteria (PSB) living in a dense phototrophic plate in the chemocline is responsible for most of the primary production in Mahoney Lake. Here, we present metagenomic data from this phototrophic plate--including the genome of the major PSB, as obtained from both a highly enriched culture and from the metagenomic data--as well as evidence for multiple other taxa that contribute to the oxidative sulfur cycle and to sulfate reduction. The planktonic PSB is a member of the Chromatiaceae, here renamed Thiohalocapsa sp. strain ML1. It produces the carotenoid okenone, yet its closest relatives are benthic PSB isolates, a finding that may complicate the use of okenone (okenane) as a biomarker for ancient PZE. Favorable thermodynamics for non-phototrophic sulfide oxidation and sulfate reduction reactions also occur in the plate, and a suite of organisms capable of oxidizing and reducing sulfur is apparent in the metagenome. Fluctuating supplies of both reduced carbon and reduced sulfur to the chemocline may partly account for the diversity of both autotrophic and heterotrophic species. Collectively, the data demonstrate the physiological potential for maintaining complex sulfur and carbon cycles in an anoxic water column, driven by the input of exogenous organic matter. This is consistent with suggestions that high levels of oxygenic primary production maintain episodes of PZE in Earth's history and that such communities should support a diversity of sulfur cycle reactions. PMID:24976102

Hamilton, T L; Bovee, R J; Thiel, V; Sattin, S R; Mohr, W; Schaperdoth, I; Vogl, K; Gilhooly, W P; Lyons, T W; Tomsho, L P; Schuster, S C; Overmann, J; Bryant, D A; Pearson, A; Macalady, J L

2014-09-01

338

Simultaneous bioreduction of nitrate and chromate using sulfur-based mixotrophic denitrification process  

Energy Technology Data Exchange (ETDEWEB)

Highlights: • Simultaneous heterotrophic and autotrophic denitrification was stimulated. • Simultaneous bioreduction of nitrate and chromate was achieved. • Total chromium decreased <50 ?g/L when the influent Cr(VI) was ?5 mg/L. -- Abstract: This study aims at evaluating simultaneous chromate and nitrate reduction using sulfur-based mixotrophic denitrification process in a column reactor packed with elemental sulfur and activated carbon. The reactor was supplemented with methanol at C/N ratio of 1.33 or 2. Almost complete denitrification was achieved at influent NO{sub 3}{sup ?}–N and Cr(VI) concentrations of 75 mg/L and 10 mg/L, respectively, and 3.7 h HRT. Maximum denitrification rate was 0.5 g NO{sub 3}{sup ?}–N/(L.d) when the bioreactor was fed with 75 mg/L NO{sub 3}{sup ?}–N, 150 mg/L methanol and 10 mg/L Cr(VI). The share of autotrophic denitrification was between 12% and 50% depending on HRT, C/N ratio and Cr(VI) concentration. Effluent total chromium was below 50 ?g/L provided that influent Cr(VI) concentration was equal or below 5 mg/L. DGGE results showed stable microbial community throughout the operation and the presence of sulfur oxidizing denitrifying bacteria (Thiobacillus denitrificans) and Cr(VI) reducing bacteria (Exiguobacterium spp.) in the column bed.

Sahinkaya, Erkan, E-mail: erkansahinkaya@yahoo.com [Istanbul Medeniyet University, Bioengineering Department, Goztepe, Istanbul (Turkey); Kilic, Adem [Harran University, Environmental Engineering Department, Osmanbey Campus, 63000 Sanliurfa (Turkey); Calimlioglu, Beste; Toker, Yasemin [Istanbul Medeniyet University, Bioengineering Department, Goztepe, Istanbul (Turkey)

2013-11-15

339

What explains the sulfur isotope fractionation observed in the aquifer system of Puebla Valley, Mexico?  

Science.gov (United States)

Puebla Valley, Mexico is located in the central part of the Trans Mexican Volcanic Belt and is surrounded by 3 large volcanoes: Popocatepetl (active since 1994), Iztaccihuatl (extinct), and Malinche (dormant). The aquifer system of the Valley contains at least two productive units: an unconfined aquifer formed mainly of alluvial and volcanic deposits and a second, confined aquifer, which has chemically distinct water that is sulfur-rich, high in CO2, and high in alkalinity. There is a current debate about the origin of the sulfur-rich water, which is being used, after treatment, to lessen the deficit of water supply to the city of Puebla (with a population of approximately 1.5 million). Sulfate and sulfide species in water from the confined aquifer have an average sulfur isotope fractionation difference of 24.6 %. This fractionation is, at least in part, the result of bacterial sulfate reduction as evidenced by testing for bacteria with BART kits. Molecular analysis to identify the specific bacteria is underway. However, analysis of carbon isotopes of dissolved CO2 (with average delta 13C of 4.4%) and 3He/4He with average ratios of 2.1 for specific wells, located in the upper aquifer and characterized by having low sulfate but also rich in CO2 and alkalinity, suggest a possible magmatic component. The carbon and helium isotope analysis of water from the confined aquifer is currently underway.

Velazquez-Oliman, G.; Perry, E. C.; Leal-Bautista, R. M.; Lenczewski, M. E.

2003-12-01

340

Can bacteria save the planet?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Bacteria might just hold the key to preserving the environment for our great grandchildren. Philip Hunter explores some of the novel ways in which systems biology and biotechnology are harnessing bacteria to produce renewable energy and clean up pollution.

Hunter, Philip

2010-01-01

 
 
 
 
341

A sulfur isotopic study of alabandites from some manganese ore deposits in Japan  

International Nuclear Information System (INIS)

Alabandites from Pretertiary bedded- and Tertiary vein-type manganese deposits in Japan have been examined for their sulfur isotopic composition. delta34 S(CDT) value ranges widely from -31 to +11 per mil in 12 specimens taken from 10 bedded type deposits. While the mineral is no more than a minor constituent in most of the deposits, the isotopic features clearly indicate that these alabandites are of bacteriogenic sedimentary origin, thus raising an important constraint for the genesis of this group of deposits. A cluster of delta34 S around -30 per mil implies an open-system, steady-state reduction (Schwarcz and Burnie, 1973) from a source SO42- with the isotopic level of ca. +20 per mil. The inferred source is likely to have been in the Triassic sea. Current conjectures upon the age of host sedimentary rocks of the deposits concerned are in favor of this view. Alabandites from the Tertiary (Miocene) vein type deposits show only a minor variation in delta34 S, +4 to +5 per mil. The data are very similar to the average isotopic composition of sulfides of the Miocene, ''Green Tuff'' mineralization represented by the kuroko type deposits. The remarkable consistency in sulfur isotopic composition of the Green Tuff mineralization over an extensive area may require a huge, common reservoir of sulfur in some form, which still remains an enigma. (author)

342

Sulfur nanocrystals anchored graphene composite with highly improved electrochemical performance for lithium-sulfur batteries  

Science.gov (United States)

Two kinds of graphene-sulfur composites with 50 wt% of sulfur are prepared using hydrothermal method and thermal mixing, respectively. Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray Spectra mapping show that sulfur nanocrystals with size of ˜5 nm dispersed on graphene sheets homogeneously for the sample prepared by hydrothermal method (NanoS@G). While for the thermal mixed graphene-sulfur composite (S-G mixture), sulfur shows larger and uneven size (50-200 nm). X-ray Photoelectron Spectra (XPS) reveals the strong chemical bonding between the sulfur nanocrystals and graphene. Comparing with the S-G mixture, the NanoS@G composite shows highly improved electrochemical performance as cathode for lithium-sulfur (Li-S) battery. The NanoS@G composite delivers an initial capacity of 1400 mAh g-1 with the sulfur utilization of 83.7% at a current density of 335 mA g-1. The capacity keeps above 720 mAh g-1 over 100 cycles. The strong adherence of the sulfur nanocrystals on graphene immobilizes sulfur and polysulfides species and suppressed the “shuttle effect”, resulting higher coulombic efficiency and better capacity retention. Electrochemical impedance also suggests that the strong bonding enabled rapid electronic/ionic transport and improved electrochemical kinetics, therefore good rate capability is obtained. These results demonstrate that the NanoS@G composite is a very promising candidate for high-performance Li-S batteries.

Zhang, Jun; Dong, Zimin; Wang, Xiuli; Zhao, Xuyang; Tu, Jiangping; Su, Qingmei; Du, Gaohui

2014-12-01

343

Three Activities: Bacteria Study, Micro Study, and Bacteria Killers  

Science.gov (United States)

This resource provides a problem-based activity on risk assessment of environmental health issues. The lesson consists of three related activities: Bacteria Study, Micro Study and Bacteria Killers. "Bacteria Study" gives students hands-on experience with the concepts of epidemiology. "Micro Study" has students sketch, observe, and compare different types of bacteria that can grow in moist conditions. "Bacteria Killers" has students determine what kills bateria, especially in common household products. Detailed instructions are provided for each activity. This resource is free to download. Users must first create a login with ATEEC's website to access the file.

344

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...

Cilliers, E. J.; Diemont, E.; Stobbelaar, D. J.; Timmermans, W.

2010-01-01

345

Denitrification by extremely halophilic bacteria  

Science.gov (United States)

Extremely halophilic bacteria were isolated from widely separated sites by anaerobic enrichment in the presence of nitrate. The anaerobic growth of several of these isolates was accompanied by the production of nitrite, nitrous oxide, and dinitrogen. These results are a direct confirmation of the existence of extremely halophilic denitrifying bacteria, and suggest that such bacteria may be common inhabitants of hypersaline environments.

Hochstein, L. I.; Tomlinson, G. A.

1985-01-01

346

Carbon, nitrogen and sulfur isotopic characterization of biological samples from chemo-synthetic communities in southern Okinawa, Japan  

Science.gov (United States)

Direct measurement of carbon, nitrogen, and sulfur isotopic compositions of the seafloor hydrothermal bacteria involves many difficulties, mainly due to lack of suitable size of samples. In contrast, the isotopic measurements of the hydrothermal vent animals can easily be made. The animals depends mainly on bacterial primary production. Carbon, nitrogen, and sulfur budget from the bacterial source should be estimated using the stable isotopic compositions of the soft tissue constituents. The hydrothermal environment involves several types of chemoautotrophc and methanotrophic bacteria such as suspending, matting, and endosymbiosis. Each hydrothermal vent animal feeds on or harbors the bacteria according to their physiology and ecology. For example, the crustaceans, Shinkaiya and Alvinocaris, feed on bacteria and the deep-sea mussel, Bathymodiolus, harbors endosymbionts in their gill tissues. Our objectives are to make clear the sources of carbon, nitrogen, and sulfur of these bacteria and the relationship between the bacteria and the geochemistry of emitting hydrothermal fluids. We studied the vent animals from two hydrothermal systems where the tectonic settings are significantly different. One is located on the volcanic front of the Ryukyu Arc and the other is located on the west edge of the Okinawa Trough back-arc basin. The former hydrothermal vent site is active in the caldera where sediment starved hydrothermal system, while the latter site is active on the thick sediment-covered small trough. The geological settings of these two hydrothermal sites would provide different geochemical environments. We will discuss how the vent animals succeed to the geochemical characteristics from the viewpoint of stable isotope geochemistry.

Yamanaka, T.; Mizota, C.; Ishibashi, J.; Nakayama, N.; Tsunogai, U.; Morimoto, Y.; Kataoka, S.; Kosaka, A.; Maki, Y.; Fujiwara, Y.; Tsuchida, S.; Fujikura, K.

2002-12-01

347

Selection and Characterization of Endophytic Bacteria as Biocontrol Agents of Tomato Bacterial Wilt Disease  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Biological control of bacterial wilt pathogen (Ralstonia solanacearum) of tomato using endophytic bacteria is one of the alternative control methods to support sustainable agriculture. This study was conducted to select and characterize endophytic bacteria isolated from healthy tomato stems and to test their ability to promote plant growth and suppress bacterial wilt disease. Among 49 isolates successfully isolated, 41 were non-plant pathogenic. Green house test on six selected isolates based...

ABDJAD ASIH NAWANGSIH; IKA DAMAYANTI; SURYO WIYONO; JUANG GEMA KARTIKA

2011-01-01

348

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

349

Exploring Green Jobs  

Science.gov (United States)

In this lesson, students complete a Myers-Briggs Type Inventory of their personality type as an introductory step to understanding what green jobs might suit their personal styles. From the information on this online tool, they look at different Green Jobs to explore possible careers.

Education, Connecticut E.

350

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

351

Green Nail Syndrome  

Science.gov (United States)

... bacterium flourishes in wet environments, such as jacuzzis, contact lens solution, sinks, and bath sponges. When it grows, it produces hallmark green pigments called pyocyanin and pyoverdin. These same pigments impart the green color of ... Us 2902 North Baltimore Street Kirksville, Missouri 63501 ...

352

Accidental fatal inhalation of sulfuric acid fumes.  

Science.gov (United States)

A man found dead with circumstantial evidence indicating exposure to sulfuric acid vapor. He had been applying a solution of concentrated sulfuric acid to a drain pipe in an attempt to clear a blockage. External examination showed moderate corrosive damage around his mouth and nose, on his forearms and tips of fingers of his left hand. Autopsy revealed congestion of the respiratory passages, as well as severe pulmonary edema. Traces of acid and sulfate compounds were chemically detected in his upper respiratory passages. Death was attributed to accidental inhalation of fumes of strong sulfuric acid during application to blocked drainpipes. PMID:17239648

Benomran, F A; Hassan, A I; Masood, S S

2008-01-01

353

Sulfuric acid/hydrogen peroxide rinsing study  

Energy Technology Data Exchange (ETDEWEB)

Sulfuric acid hydrogen peroxide mixtures (SPM) are commonly used in the semiconductor industry to remove organic contaminants from wafer surfaces. This viscous solution is very difficult to rinse off water surfaces. Various rinsing conditions were tested and the resulting residual acid left on the water surface was measured. Particle growth resulting from incomplete rinse is correlated with the amount of sulfur on the wafer surface measured by Time of Flight Secondary Ion Mass Spectroscopy (TOF-SIMS). The amount of sulfur on the wafer structure after the rinse step is strongly affected by the wafer film type and contact angle prior to the SPM clean.

Clews, P.J.; Nelson, G.C.; Matlock, C.A. [and others

1995-12-01

354

[Immunobiological properties of bacteria].  

Science.gov (United States)

Opsonins found on the surface of microbial cells in vivo and ex vivo are characterized. The possibility of their visualization by immune electron and fluorescent microscopy has been demonstrated. Opsonins are shown to play a role in immune-mediated adhesion of bacteria to phagocytes and erythrocytes and formation of virus-bacterium associations. Staphylococci, Streptococci, and Propionibacteria appear to actively adsorb blood proteins on their cell surface giving rise to well-apparent capsular structures tentatively called immunoglobulin coatings. Pathogen (microorganism)-associated molecular patterns of gram-positive and gram-negative bacteria show different degree of interaction with soluble proteins that in turn promote their adhesion to blood corpuscles. The role of erythrocytes in transportation and elimination of immune complexes bound to their membrane receptors is discussed. PMID:21312383

Bykov, A S; Bykov, S A; Romanovskaia, L M; Solntseva, V K; Fomina, E S

2010-01-01

355

Manufacture of Probiotic Bacteria  

Science.gov (United States)

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

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

356

Bacteria, food, and cancer.  

Science.gov (United States)

Gut microbes are essential components of the human organism-helping us metabolize food into energy, produce micronutrients, and shape our immune systems. Having a particular pattern of gut microbes is also increasingly being linked to medical conditions including obesity, inflammatory bowel disease, and diabetes. Recent studies now indicate that our resident intestinal bacteria may also play a critical role in determining one's risk of developing cancer, ranging from protection against cancer to promoting its initiation and progression. Gut bacteria are greatly influenced by diet and in this review we explore evidence that they may be the missing piece that explains how dietary intake influences cancer risk, and discuss possible prevention and treatment strategies. PMID:21876723

Rooks, Michelle G; Garrett, Wendy S

2011-01-01

357

Sulfur oxidizers dominate carbon fixation at a biogeochemical hot spot in the dark ocean.  

Science.gov (United States)

Bacteria and archaea in the dark ocean (>200 m) comprise 0.3-1.3 billion tons of actively cycled marine carbon. Many of these microorganisms have the genetic potential to fix inorganic carbon (autotrophs) or assimilate single-carbon compounds (methylotrophs). We identified the functions of autotrophic and methylotrophic microorganisms in a vent plume at Axial Seamount, where hydrothermal activity provides a biogeochemical hot spot for carbon fixation in the dark ocean. Free-living members of the SUP05/Arctic96BD-19 clade of marine gamma-proteobacterial sulfur oxidizers (GSOs) are distributed throughout the northeastern Pacific Ocean and dominated hydrothermal plume waters at Axial Seamount. Marine GSOs expressed proteins for sulfur oxidation (adenosine phosphosulfate reductase, sox (sulfur oxidizing system), dissimilatory sulfite reductase and ATP sulfurylase), carbon fixation (ribulose-1,5-bisphosphate carboxylase oxygenase (RuBisCO)), aerobic respiration (cytochrome c oxidase) and nitrogen regulation (PII). Methylotrophs and iron oxidizers were also active in plume waters and expressed key proteins for methane oxidation and inorganic carbon fixation (particulate methane monooxygenase/methanol dehydrogenase and RuBisCO, respectively). Proteomic data suggest that free-living sulfur oxidizers and methylotrophs are among the dominant primary producers in vent plume waters in the northeastern Pacific Ocean. PMID:23842654

Mattes, Timothy E; Nunn, Brook L; Marshall, Katharine T; Proskurowski, Giora; Kelley, Deborah S; Kawka, Orest E; Goodlett, David R; Hansell, Dennis A; Morris, Robert M

2013-12-01

358

Green Valley Galaxies  

CERN Document Server

The "green valley" is a wide region separating the blue and the red peaks in the ultraviolet-optical color magnitude diagram, first revealed using GALEX UV photometry. The term was coined by Christopher Martin in 2005. Green valley highlights the discriminating power of UV to very low relative levels of ongoing star formation, to which the optical colors, including u-r, are insensitive. It corresponds to massive galaxies below the star-forming "main" sequence, and therefore represents a critical tool for the study of the quenching of star formation and its possible resurgence in otherwise quiescent galaxies. This article reviews the results pertaining to morphology, structure, environment, dust content and gas properties of green valley galaxies in the local universe. Their relationship to AGN is also discussed. Attention is given to biases emerging from defining the "green valley" using optical colors. We review various evolutionary scenarios and we present evidence for a new, quasi-static view of the green ...

Salim, Samir

2015-01-01

359

"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

360

Glacial lake hides bacteria  

Science.gov (United States)

This article highlights the published work of a geomicrobiology research team led by Eric Gaidos from the University of Hawaii and Brian Lanoil, from the University of California, Riverside. This group reports the identification of bacteria from an Icelandic sub-glacial lake, and how the collection and description of these microorganisms immured within glacial ice and sub-surface water serve as a model in the search for extra-terrestrial life.

Peplow, Mark; Online, Bioed

 
 
 
 
361

Bacteria are not Lamarckian  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Instructive influence of environment on heredity has been a debated topic for centuries. Darwin's identification of natural selection coupled to chance variation as the driving force for evolution, against a formal interpretation proposed by Lamarck, convinced most scientists that environment does not specifically instruct evolution in an oriented direction. This is true for multicellular organisms. In contrast, bacteria were long thought of as prone to receive oriented infl...

Danchin, Antoine

2007-01-01

362

Growing Unculturable Bacteria  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The bacteria that can be grown in the laboratory are only a small fraction of the total diversity that exists in nature. At all levels of bacterial phylogeny, uncultured clades that do not grow on standard media are playing critical roles in cycling carbon, nitrogen, and other elements, synthesizing novel natural products, and impacting the surrounding organisms and environment. While molecular techniques, such as metagenomic sequencing, can provide some information independent of our ability...

Stewart, Eric J.

2012-01-01

363

Antibiotic Resistant Bacteria  

Science.gov (United States)

This week's Topic In Depth is about antibiotic resistant bacteria.The first site is a recent news report from BBC news (1) that describes some recent research on resistant strains of two "of the world's most dangerous bacteria. Next is a Centers for Disease Control (CDC) page (2) with a brief background on antibiotic resistance and how to prevent it. A much more in-depth report is provided by the Select Committee on Science and Technology of the British House of Lords (3). There has been some public concern over the use of antibiotic resistant bacteria strains as markers in genetically modified food crops. The next two resources present information specific to this topic. The first is from the European Federation of Biotechnology (4), and the second is a shorter report from the Council for Biotechnology Information (5). The Alliance for the Prudent Use of Antibiotics (6) has a consumer and patient information section that explains what individuals can do to help prevent the problem from increasing. Readers who need a brief primer on antibiotics may appreciate this Web site from the University of Edinburgh (7). The last site is a "bugs in the news" feature from the University of Kansas (8), which is an easy-to-read explanation of "what the heck" antibiotic resistance is.

Lee, Amy.

2002-01-01

364

Sputum colour and bacteria in chronic bronchitis exacerbations: a pooled analysis.  

Science.gov (United States)

We examined the correlation between sputum colour and the presence of potentially pathogenic bacteria in acute exacerbations of chronic bronchitis (AECBs). Data were pooled from six multicentre studies comparing moxifloxacin with other antimicrobials in patients with an AECB. Sputum was collected before antimicrobial therapy, and bacteria were identified by culture and Gram staining. Association between sputum colour and bacteria was determined using logistic regression. Of 4,089 sputum samples, a colour was reported in 4,003; 1,898 (46.4%) were culture-positive. Green or yellow sputum samples were most likely to yield bacteria (58.9% and 45.5% of samples, respectively), compared with 18% of clear and 39% of rust-coloured samples positive for potentially pathogenic microorganisms. Factors predicting a positive culture were sputum colour (the strongest predictor), sputum purulence, increased dyspnoea, male sex and absence of fever. Green or yellow versus white sputum colour was associated with a sensitivity of 94.7% and a specificity of 15% for the presence of bacteria. Sputum colour, particularly green and yellow, was a stronger predictor of potentially pathogenic bacteria than sputum purulence and increased dyspnoea in AECB patients. However, it does not necessarily predict the need for antibiotic treatment in all patients with AECB. PMID:22034649

Miravitlles, Marc; Kruesmann, Frank; Haverstock, Daniel; Perroncel, Renee; Choudhri, Shurjeel H; Arvis, Pierre

2012-06-01

365

Sulfurized carbon: a class of cathode materials for high performance lithium/sulfur batteries  

Directory of Open Access Journals (Sweden)

Full Text Available Liquid electrolyte lithium/sulfur (Li/S batteries cannot come into practical applications because of many problems such as low energy efficiency, short cycle life, and fast self-discharge. All these problems are related to the dissolution of lithium polysulfide, a series of sulfur reduction intermediates, in the liquid electrolyte, and resulting parasitic reactions with the Li anode. Covalently binding sulfur onto carbon surface is a solution to completely eliminate the dissolution of lithium polysulfide and make the Li/S battery viable for practical applications. This can be achieved by replacing elemental sulfur with sulfurized carbon as the cathode material. This article reviews the current efforts on this subject and discusses the syntheses, electrochemical properties, and prospects of the sulfurized carbon as a cathode material in the rechargeable Li/S batteries.

ShengS.Zhang

2013-12-01

366

Sulfur in hierarchically pore-structured carbon pillars as cathode material for lithium–sulfur batteries  

International Nuclear Information System (INIS)

Highlights: ? Hierarchically pore-structured carbon pillars (HPC) is prepared by directly pyrolyzing Al-based porous coordination polymers (Al-PCP). ? Evidences for the location of sulfur in the HPC and the interaction between S and C are provided. ? This HPC/S composite shows good electrochemical performances as cathode of lithium–sulfur batteries. -- Abstract: Hierarchically pore-structured carbon (HPC) pillars with a high surface area and large pore volume are obtained by pyrolyzing Al-based porous coordination polymers (Al-PCP) and used as a matrix of the sulfur for lithium–sulfur (Li–S) batteries. The structure and electrochemical performance of the sulfur-impregnated HPC are characterized. The improved performance of the composite is ascribed to the unique porous structure of the HPC matrix and its strong interaction with sulfur

367

Inhibitory effect of iron-oxidizing bacteria on ferrous-promoted chalcopyrite leaching  

Science.gov (United States)

It is generally accepted that iron-oxidizing bacteria, Thiobacillus ferrooxidans, enhance chalcopyrite leaching. However, this article details a case of the bacteria suppressing chalcopyrite leaching. Bacterial leaching experiments were performed with sulfuric acid solutions containing 0 or 0.04 mol/dm3 ferrous sulfate. Without ferrous sulfate, the bacteria enhance copper extraction and oxidation of ferrous ions released from chalcopyrite. However, the bacteria suppressed chalcopyrite leaching when ferrous sulfate was added. This is mainly due to the bacterial consumption of ferrous ions which act as a promoter for chalcopyrite oxidation with dissolved oxygen. Coprecipitation of copper ions with jarosite formed by the bacterial ferrous oxidation also causes the bacterial suppression of copper extraction. Copyright 1999 John Wiley & Sons, Inc. PMID:10397886

Hiroyoshi; Hirota; Hirajima; Tsunekawa

1999-08-20

368

Improved Cyclability of Liquid Electrolyte Lithium/Sulfur Batteries by Optimizing Electrolyte/Sulfur Ratio  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A liquid electrolyte lithium/sulfur (Li/S) cell is a liquid electrochemical system. In discharge, sulfur is first reduced to highly soluble Li2S8, which dissolves into the organic electrolyte and serves as the liquid cathode. In solution, lithium polysulfide (PS) undergoes a series of complicated disproportionations, whose chemical equilibriums vary with the PS concentration and affect the cell’s performance. Since the PS concentration relates to a certain electrolyte/sulfur (E/S) r...

Zhang, Sheng S.

2012-01-01

369

Mass-independent sulfur of inclusions in diamond and sulfur recycling on early Earth.  

Science.gov (United States)

Populations of sulfide inclusions in diamonds from the Orapa kimberlite pipe in the Kaapvaal-Zimbabwe craton, Botswana, preserve mass-independent sulfur isotope fractionations. The data indicate that material was transferred from the atmosphere to the mantle in the Archean. The data also imply that sulfur is not well mixed in the diamond source regions, allowing for reconstruction of the Archean sulfur cycle and possibly offering insight into the nature of mantle convection through time. PMID:12493909

Farquhar, J; Wing, B A; McKeegan, K D; Harris, J W; Cartigny, P; Thiemens, M H

2002-12-20

370

Sulfurized carbon: a class of cathode materials for high performance lithium/sulfur batteries  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Liquid electrolyte lithium/sulfur (Li/S) batteries cannot come into practical applications because of many problems such as low energy efficiency, short cycle life, and fast self-discharge. All these problems are related to the dissolution of lithium polysulfide, a series of sulfur reduction intermediates, in the liquid electrolyte, and resulting parasitic reactions with the Li anode. Covalently binding sulfur onto carbon surface is a solution to completely eliminate the dissolution of lithiu...

ShengS.Zhang

2013-01-01

371

Succession of Internal Sulfur Cycles and Sulfur-Oxidizing Bacterial Communities in Microaerophilic Wastewater Biofilms  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The succession of sulfur-oxidizing bacterial (SOB) community structure and the complex internal sulfur cycle occurring in wastewater biofilms growing under microaerophilic conditions was analyzed by using a polyphasic approach that employed 16S rRNA gene-cloning analysis combined with fluorescence in situ hybridization, microelectrode measurements, and standard batch and reactor experiments. A complete sulfur cycle was established via S0 accumulation within 80 days in the biofilms in replicat...

Okabe, Satoshi; Ito, Tsukasa; Sugita, Kenichi; Satoh, Hisashi

2005-01-01

372

Magnetotactic bacteria. Promising biosorbents for heavy metals  

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-09-15

373

Complete genome sequence of the sulfur compounds oxidizing chemolithoautotroph Sulfuricurvum kujiense type strain (YK-1T)  

Energy Technology Data Exchange (ETDEWEB)

Sulfuricurvum kujiense Kodama and Watanabe 2004 is the type species of the monotypic genus Sulfuricurvum, which belongs to the family Helicobacteriaceae in the class Epsilonproteobacteria. The species is of interest because it is frequently found in crude oil and oil sands where it utilizes various reduced sulfur compounds such as elemental sulfur, sulfide and thiosulfate as electron donors. Members of the species do not utilize sugars, organic acids and hydrocarbons as carbon and energy sources. This is the first completed genome sequence of a member of the genus Sulfuricurvum. The genome, which consists of a circular chromosome of 2,574,824 bp length and four plasmids of 118,585 bp, 71,513 bp, 51,014 bp, and 3,421 bp length, respectively, harboring a total of 2,879 protein-coding and 61 RNA genes and is a part of the Genomic Encyclopedia of Bacteria and Archaea project.

Han, Cliff [Los Alamos National Laboratory (LANL); Kotsyurbenko, Oleg [Technical University of Braunschweig; Chertkov, Olga [Los Alamos National Laboratory (LANL); Held, Brittany [Los Alamos National Laboratory (LANL); Lapidus, Alla L. [U.S. Department of Energy, Joint Genome Institute; Nolan, Matt [U.S. Department of Energy, Joint Genome Institute; Lucas, Susan [U.S. Department of Energy, Joint Genome Institute; Hammon, Nancy [U.S. Department of Energy, Joint Genome Institute; Deshpande, Shweta [U.S. Department of Energy, Joint Genome Institute; Cheng, Jan-Fang [U.S. Department of Energy, Joint Genome Institute; Tapia, Roxanne [Los Alamos National Laboratory (LANL); Goodwin, Lynne A. [Los Alamos National Laboratory (LANL); Pitluck, Sam [U.S. Department of Energy, Joint Genome Institute; Liolios, Konstantinos [U.S. Department of Energy, Joint Genome Institute; Pagani, Ioanna [U.S. Department of Energy, Joint Genome Institute; Ivanova, N [U.S. Department of Energy, Joint Genome Institute; Mavromatis, K [U.S. Department of Energy, Joint Genome Institute; Mikhailova, Natalia [U.S. Department of Energy, Joint Genome Institute; Pati, Amrita [U.S. Department of Energy, Joint Genome Institute; Chen, Amy [U.S. Department of Energy, Joint Genome Institute; Palaniappan, Krishna [U.S. Department of Energy, Joint Genome Institute; Land, Miriam L [ORNL; Hauser, Loren John [ORNL; Chang, Yun-Juan [ORNL; Jeffries, Cynthia [Oak Ridge National Laboratory (ORNL); Brambilla, Evelyne-Marie [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Rohde, Manfred [HZI - Helmholtz Centre for Infection Research, Braunschweig, Germany; Spring, Stefan [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Sikorski, Johannes [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Goker, Markus [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Woyke, Tanja [U.S. Department of Energy, Joint Genome Institute; Bristow, James [U.S. Department of Energy, Joint Genome Institute; Eisen, Jonathan [U.S. Department of Energy, Joint Genome Institute; Markowitz, Victor [U.S. Department of Energy, Joint Genome Institute; Hugenholtz, Philip [U.S. Department of Energy, Joint Genome Institute; Kyrpides, Nikos C [U.S. Department of Energy, Joint Genome Institute; Klenk, Hans-Peter [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Detter, J. Chris [U.S. Department of Energy, Joint Genome Institute

2012-01-01

374

Molecular characterization of symbiotic associations between chemoautotrophic sulfur-oxidizing microorganisms and nematodes in shallow marine sediments  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Shallow marine sediments are preferred environments for nematodes harboring endo- or ectosymbiotic microorganisms. In most cases, the symbionts are autotrophic, sulfur-oxidizing bacteria. In the present work molecular biological methods such as comparative 16S rRNA and 18S rRNA sequence analysis, fluorescence in situ hybridization (FISH) and slot blot hybridization with group specific rRNA-targeted oligonucleotide probes were used to investigate and characterize these symbiotic associations a...

Musat, Niculina

2006-01-01

375

SULFUR COMPOUNDS IN PETROLEUM HYDROCARBON STREAMS  

Directory of Open Access Journals (Sweden)

Full Text Available Determination of concentrations of sulfur compounds in different petroleum samples is a true analytical challenge. Only analytical procedures based on gas chromatography can meet the sensitivity and accuracy requirements dictated by up-to-date petroleum industry.The objective of this work is to develop the method for the quantifying of sulfur compounds in petroleum hydrocarbon streams. The optimum parameters for the GC-SCD method are found in order to determine of sulfur compounds in petroleum fractions. The present study is limited to fractions with final boiling point up to 100°C from the refining unit. Twelve petroleum samples are analyzed. The total sulfur contents of these samples are determined by GC-SCD and UV fluorescence detection. The data obtained are agreement.

Antoaneta Pavlova

2012-03-01

376

Sulfur Speciation in Lunar and Terrestrial Apatite  

Science.gov (United States)

Apatite from 14072,16, 14053,61, and 14053,241 have S K? peak shifts consistent with incorporation of both sulfide and sulfate. Sulfur concentration is inversely correlated with the percentage of sulfide.

Boyce, J. W.; Ma, C.; Eiler, J. M.; Baker, M. B.; Liu, Y.; Stolper, E. M.; Taylor, L. A.

2012-03-01

377

Zapoteca formosa: sulfur chemistry and phytotoxicity.  

Science.gov (United States)

Chemical analysis of Zapoteca formosa extracts show that a variety of volatile sulfur-containing components, including cyclic polysulfides, are responsible for the distinctive odor of its germinating seeds and young plants. The major sulfur-containing compounds include acetyl djenkolic acid, djenkolic acid, taurine, cystine, benzothiazole, dimethyl disulfide, 2,4-dithiapentane, 2-hydroxyethylmethylsulfide, trithiane, 1,2,4-trithiolane, and 1,2,4,6-tetrathiepane. Decreased amounts of djenkolic acid in seedlings and young plants, as compared to the seed, indicate that this is likely the metabolic precursor of the volatile sulfur components. Germination and radicle elongation assays show that germinating seeds of Zapoteca and mixtures of volatile sulfur-containing compounds are highly phytotoxic to Cucumis sativa, Lactuca sativa, Lycopersicon esculentum, and Acacria farnesiana. PMID:15112733

Lane, Nancy; Weidenhamer, Jeffrey D; Romeo, John T

2004-02-01

378

Effects of sulfur dioxide and heavy metals  

International Nuclear Information System (INIS)

Produced from burning coal, sulfur dioxide persists not so much from home heating as in the furnaces of coal-fired, electric power-generating plants. Particulate emissions may be over 99% controlled, and sulfur dioxide may be 70-90% controlled in some countries, but older plants or newer facilities in developing countries often lack such technology. Even where controls exist, the tremendous amounts of coal burned still result in the emission of significant quantities of sulfur dioxide. And despite pollution control equipment in modern smelters, the sulfur dioxide and heavy metal particulate emissions can still damage neighboring vegetation. The problem is especially critical in developing countries where control technology is lacking, or in developed countries where control has a low priority

379

Dual protection of sulfur by carbon nanospheres and graphene sheets for lithium-sulfur batteries.  

Science.gov (United States)

Well-confined elemental sulfur was implanted into a stacked block of carbon nanospheres and graphene sheets through a simple solution process to create a new type of composite cathode material for lithium-sulfur batteries. Transmission electron microscopy and elemental mapping analysis confirm that the as-prepared composite material consists of graphene-wrapped carbon nanospheres with sulfur uniformly distributed in between, where the carbon nanospheres act as the sulfur carriers. With this structural design, the graphene contributes to direct coverage of sulfur to inhibit the mobility of polysulfides, whereas the carbon nanospheres undertake the role of carrying the sulfur into the carbon network. This composite achieves a high loading of sulfur (64.2?wt?%) and gives a stable electrochemical performance with a maximum discharge capacity of 1394?mAh?g(-1) at a current rate of 0.1?C as well as excellent rate capability at 1?C and 2?C. The improved electrochemical properties of this composite material are attributed to the dual functions of the carbon components, which effectively restrain the sulfur inside the carbon nano-network for use in lithium-sulfur rechargeable batteries. PMID:24692070

Wang, Bei; Wen, Yanfen; Ye, Delai; Yu, Hua; Sun, Bing; Wang, Guoxiu; Hulicova-Jurcakova, Denisa; Wang, Lianzhou

2014-04-25

380

Green growth in fisheries  

DEFF Research Database (Denmark)

Climate change and economic growth have gained a substantial amount of attention over the last decade. Hence, in order to unite the two fields of interest, the concept of green growth has evolved. The concept of green growth focuses on how to achieve growth in environment-dependent sectors, without harming the environment. Fishery is an environment-dependent sector and it has been argued that there is no potential for green growth in the sector owing to global overexploitation, leaving no scope for production growth. The purpose of this paper is to explain what green growth is and to develop a conceptual framework. Furthermore, the aim is to show that a large green growth potential actually exists in fisheries and to show how this potential can be achieved. The potential green growth appears as value-added instead of production growth. The potential can be achieved by reducing overcapacity, investing in the rebuilding of fish stocks and a coordinated regulation of marine activities that interact with fisheries. Incentive-based regulation of fisheries that counterbalances services of the ecosystems is an important instrument to achieve green growth.

Nielsen, Max; Ravensbeck, Lars

2014-01-01

 
 
 
 
381

Polymer Electrolytes for Lithium/Sulfur Batteries  

Directory of Open Access Journals (Sweden)

Full Text Available This review evaluates the characteristics and advantages of employing polymer electrolytes in lithium/sulfur (Li/S batteries. The main highlights of this study constitute detailed information on the advanced developments for solid polymer electrolytes and gel polymer electrolytes, used in the lithium/sulfur battery. This includes an in-depth analysis conducted on the preparation and electrochemical characteristics of the Li/S batteries based on these polymer electrolytes.

The Nam Long Doan

2012-08-01

382

Thermodynamic study of phosphogypsum decomposition by sulfur  

International Nuclear Information System (INIS)

Graphical abstract: Innovation of this paper is a new and advanced process of phosphogypsum decomposition by sulfur for sulfuric acid production. Fig. 4 of this manuscript can indicate the innovation appropriately. Highlights: ? A new and advanced process for sulfuric acid production from phosphogypsum was proposed. ? Thermodynamic simulation of the new process was studied. ? Specific experiments were carried out to verify the thermodynamic simulation. ? Reaction heat of the new process were lower than that of traditional coke reduction process. - Abstract: Phosphogypsum (PG) is one of the most significant industrial solid wastes from the phosphorus chemical industry. In order to utilize PG more effectively, a new decomposition process of PG by sulfur as a reducer is proposed in this work. Thermodynamic study of the sulfur reduction process including two-step reactions was carried out by both thermodynamic simulation and experimental research. The simulation results indicate that sulfur changes its form in a complex way with rising temperature. The final decomposition temperature of PG by simulation is 993 K in the first-step reaction, and this is in good agreement with that obtained by the experiments. For the second-step reaction, however, the final PG decomposition temperature from the experiments is 250 K lower than the simulation results predict. The reaction heat of the sulfur reduction process is 27.95% less than that of the traditional coke reduction pf the traditional coke reduction process at T = 1473 K based on enthalpy change calculations. This new process can reduce the emission of CO2 effectively and is more suitable for resource utilization of PG than the coke reduction process, so it may be a promising method for sulfuric acid production from PG.

383

Ocular Effects of Sulfur Mustard  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: To review current knowledge about ocular effects of sulfur mustard (SM and the associated histopathologic findings and clinical manifestationsMethods: Literature review of medical articles (human and animal studies was accomplished using PubMed, Scopus and ISI databases. A total of 274 relevant articles in English were retrieved and reviewed thoroughly.Results: Eyes are the most sensitive organs to local toxic effects of mustard gas. Ocular injuries are mediated through different toxic mechanisms including: biochemical damages, biomolecular and gene expression modification, induction of immunologic and inflammatory reactions, disturbing ultrastructural architecture of the cornea, and long-lasting corneal denervation. The resulting ocular injuries can roughly be categorized into acute or chronic complications. Most of the patients recover from acute injuries, but a minority of victims will suffer from chronic ocular complications. Mustard gas keratopathy (MGK is a devastating late complication of SM intoxication that proceeds from limbal stem cell deficiency (LSCD.Conclusion: SM induces several different damaging changes in case of ocular exposure; hence leading to a broad spectrum of ocular manifestations in terms of severity, timing and form. Unfortunately, no effective strategy has been introduced yet to inhibit or restore these damaging changes.

Yunes Panahi

2013-06-01

384

Transstadial and horizontal transfer of bacteria within a colony of Anopheles gambiae (Diptera: Culicidae) and oviposition response to bacteria-containing water.  

Science.gov (United States)

In a paratransgenic approach, genetically modified bacteria are utilized to kill the parasite in the vector gut. A critical component for paratransgenics against malaria is how transgenic bacteria can be introduced and then kept in a mosquito population. Here, we investigated transstadial and horizontal transfer of bacteria within an Anopheles gambiae mosquito colony with the focus on spiked breeding sites as a possible means of introducing bacteria to mosquitoes. A Pantoea stewartii strain, previously isolated from An. gambiae, marked with a green fluorescent protein (GFP), was introduced to mosquitoes in different life stages. The following life stages or older mosquitoes in the case of adults were screened for bacteria in their guts. In addition to P. stewartii other bacteria were isolated from the guts: these were identified by 16S rRNA sequence analysis and temporal temperature gradient gel electrophoresis (TTGE). Bacteria were transferred from larvae to pupae but not from pupae to adults. The mosquitoes were able to take up bacteria from the water they emerged from and transfer the same bacteria to the water they laid eggs in. Elizabethkingia meningoseptica was more often isolated from adult mosquitoes than P. stewartii. A bioassay was used to examine An. gambiae oviposition responses towards bacteria-containing solutions. The volatiles emitted from the solutions were sampled by headspace-solid phase microextraction (SPME) and identified by gas chromatography and mass spectrometry (GC-MS) analysis. P. stewartii but not E. meningoseptica mediated a positive oviposition response. The volatiles emitted by P. stewartii include indole and 3-methyl-1-butanol, which previously have been shown to affect An. gambiae mosquito behaviour. E. meningoseptica emitted indole but not 3-methyl-1-butanol, when suspended in saline. Taken together, this indicates that it may be possible to create attractive breeding sites for distribution of genetically modified bacteria in the field in a paratransgenic approach against malaria. Further research is needed to determine if the bacteria are also transferred in the same way in nature. PMID:18671931

Lindh, J M; Borg-Karlson, A-K; Faye, I

2008-09-01

385

The role of system-specific molecular chaperones in the maturation of molybdoenzymes in bacteria.  

Science.gov (United States)

Biogenesis of prokaryotic molybdoenzymes is a complex process with the final step representing the insertion of a matured molybdenum cofactor (Moco) into a folded apoenzyme. Usually, specific chaperones of the XdhC family are required for the maturation of molybdoenzymes of the xanthine oxidase family in bacteria. Enzymes of the xanthine oxidase family are characterized to contain an equatorial sulfur ligand at the molybdenum center of Moco. This sulfur ligand is inserted into Moco while bound to the XdhC-like protein and before its insertion into the target enzyme. In addition, enzymes of the xanthine oxidase family bind either the molybdopterin (Mo-MPT) form of Moco or the modified molybdopterin cytosine dinucleotide cofactor (MCD). In both cases, only the matured cofactor is inserted by a proofreading process of XdhC. The roles of these specific XdhC-like chaperones during the biogenesis of enzymes of the xanthine oxidase family in bacteria are described. PMID:21151514

Neumann, Meina; Leimkühler, Silke

2011-01-01

386

Geochemistry of sulfur isotopes in basaltic rocks  

International Nuclear Information System (INIS)

Sulfur isotope ratios in oceanic basalts from three different localities (Bermuda Triangle, East Pacific Rise, and Galapagos Spreading Centre and in terrestrial basalts from Saudi Arabia have been analyzed by mass spectroscopy. In order to recognize and to interpret, if possible, secondary isotopic changes of basalts, various sulfurous materials occurring together with basalts gypsum, deep thermal pyrites) have been investigated too. By mechanochemical sample preparation it was possible to determine various sulfur carriers separately. Sulfides occurring as droplets in basalts showed values of -0.4 to -0.8 0/00 in materials from Bermuda Triangle, Galapagos Spreading Centre, and Saudi Arabia. The values are in agreement with those suggested for primary sulfur in the earth mantle. The basalts of East Pacific Rise show a significant 34S enrichment with a mean value of +3 0/00, which may be caused by processes in the course of magmatic differentiation. Because of secondary effects sulfate sulfur, including secondary pyrite, varies considerably in its sulfur isotope ratio (delta values between -12 to +22 0/00). Samples without recognizable secondary effects have delta values of about +1.5 0/00, which can be supposed for primary sulfates. Mechanically separated pyrites from deep thermal superimposed basalts show slightly negative 34S values4S values

387

Theoretical studies of the marine sulfur cycle  

Science.gov (United States)

Several reduced sulfur compounds are produced by marine organisms and then enter the atmosphere, where they are oxidized and ultimately returned to the ocean or the land. The oceanic dimethyl sulfide (DMS) flux, in particular, represents a significant fraction of the annual global sulfur input to the atmosphere. In the atmosphere, this gas is converted to sulfur dioxide (SO2), methane sulfonic acid, and other organic acids which are relatively stable and about which little is known. SO2 is a short lived gas which, in turn, is converted to sulfuric acid and other sulfate compounds which contribute significantly to acid rain. Because of the complexity of the sulfur system, it is not well understood even in the unperturbed atmosphere. However, a number of new observations and experiments have led to a significant increase in the understanding of this system. A number of one dimensional model experiments were conducted on the gas phase part of the marine sulfur cycle. The results indicate the measured concentration of DMS and the amplitude of its diurnal cycle are in agreement with estimates of its global flux. It was also found that DMS can make a large contribution to the background SO2 concentration in the free troposphere. Estimates of CS2 concentrations in the atmosphere are inconsistent with estimated fluxes; however, measured reaction rates are consistent with the observed steep tropospheric gradient in CS2. Observations of CS2 are extremely sparse. Further study is planned.

Toon, Owen B.; Kasting, James B.; Liu, May S.

1985-01-01

388

The biology of reactive sulfur species (RSS).  

Science.gov (United States)

Sulfur is an essential and quantitatively important element for living organisms. Plants contain on average approximately 1 g S kg?¹ dry weight (for comparison plants contain approximately 15 g N kg?¹ dry weight). Sulfur is a constituent of many organic molecules, for example amino acids such as cysteine and methionine and the small tripeptide glutathione, but sulfur is also essential in the form of Fe-S clusters for the activity of many enzymes, particularly those involved in redox reactions. Sulfur chemistry is therefore important. In particular, sulfur in the form of thiol groups is central to manifold aspects of metabolism. Because thiol groups are oxidized and reduced easily and reversibly, the redox control of cellular metabolism has become an increasing focus of research. In the same way that oxygen and nitrogen have reactive species (ROS and RNS), sulfur too can form reactive molecular species (RSS), for example when a -SH group is oxidized. Indeed, several redox reactions occur via RSS intermediates. Several naturally occurring S-containing molecules are themselves RSS and because they are physiologically active they make up part of the intrinsic plant defence repertoire against herbivore and pathogen attack. Furthermore, RSS can also be used as redox-active pharmacological tools to study cell metabolism. The aim of this review is to familiarize the general reader with some of the chemical concepts, terminology and biology of selected RSS. PMID:22541352

Gruhlke, Martin C H; Slusarenko, Alan J

2012-10-01

389

Sulfur-Iodine thermochemical cycle for hydrogen production  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of the thesis was to study the Sulfur-Iodine thermochemical cycle for hydrogen production. There were three reactions in this cycle: Bunsen reaction, sulfuric acid decomposition and the hydriodic acid decomposition. The sulfuric acid decomposition required most heat in these three reactions. The thermal efficiency of this cycle mostly affects this section. The HYSYS simulator by Aspen Technologies was used for sulfuric acid decomposition. There were two steps in this section: sulfuric...

Dan, Huang

2009-01-01

390

Redox control of sulfur degassing in silicic magmas  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Explosive eruptions involve mainly silicic magmas in which sulfur solubility and diffusivity are low. This inhibits sulfur exsolution during magma uprise as compared to more mafic magmas such as basalts. Silicic magmas can nevertheless liberate large quantities of sulfur as shown by the monitoring of SO2 in recent explosive silicic eruptions in arc settings, which invariably have displayed an excess of sulfur relative to that calculated from melt degassing. If this excess sulfur is stored in ...

Scaillet, Bruno; Cle?mente, Be?atrice; Evans, Bernard W.; Pichavant, Michel

1998-01-01

391

Microphysical simulations of sulfur burdens from stratospheric sulfur geoengineering  

Directory of Open Access Journals (Sweden)

Full Text Available 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 of SO2 in a narrow band around the equator to have limited efficacy while broadening the injecting zone as well as injecting particles instead of SO2 gas increases the sulfate burden for a given injection rate, in agreement with previous work. We find that injecting H2SO4 gas instead of SO2 does not discernibly alter sulfate size or mass, in contrast with a previous study using a plume model with a microphysical model. However, the physics and chemistry in aircraft plumes, which are smaller than climate model grid cells, need to be more carefully considered. We also find significant perturbations to tropospheric aerosol for all injections studied, particularly in the upper troposphere and near the poles, where sulfate burden increases by up to 100 times. This enhanced burden could have implications for tropospheric radiative forcing and chemistry. These results highlight the need to mitigate greenhouse gas emissions rather than attempt to cool the planet through geoengineering, and to further study geoengineering before it can be seriously considered as a climate intervention option.

J. M. English

2012-05-01

392

Microphysical simulations of sulfur burdens from stratospheric sulfur geoengineering  

Directory of Open Access Journals (Sweden)

Full Text Available 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 of SO2 in a narrow band around the equator to have limited efficacy while broadening the injecting zone as well as injecting particles instead of SO2 gas increases the sulfate burden for a given injection rate, in agreement with previous work. We find that injecting H2SO4 gas instead of SO2 does not discernibly alter sulfate size or mass, in contrast with a previous study using a plume model with a microphysical model. However, the physics and chemistry in aircraft plumes, which are smaller than climate model grid cells, need to be more carefully considered. We find equatorial injections increase aerosol optical depth in the Northern Hemisphere more than the Southern Hemisphere, potentially inducing regional climate changes. We also find significant perturbations to tropospheric aerosol for all injections studied, particularly in the upper troposphere and near the poles, where sulfate burden increases by up to 100 times. This enhanced burden could have implications for tropospheric radiative forcing and chemistry. These results highlight the need to mitigate greenhouse gas emissions through means other than geoengineering, and to further study geoengineering before it can be seriously considered as a climate intervention option.

J. M. English

2012-01-01

393

A Flow-Cytometric Gram-Staining Technique for Milk-Associated Bacteria  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A Gram-staining technique combining staining with two fluorescent stains, Oregon Green-conjugated wheat germ agglutinin (WGA) and hexidium iodide (HI) followed by flow-cytometric detection is described. WGA stains gram-positive bacteria while HI binds to the DNA of all bacteria after permeabilization by EDTA and incubation at 50°C for 15 min. For WGA to bind to gram-positive bacteria, a 3 M potassium chloride solution was found to give the highest fluorescence intensity. A total of 12 strain...

Holm, Claus; Jespersen, Lene

2003-01-01

394

Relativistic Coulomb Green’s function in d dimensions  

International Nuclear Information System (INIS)

Using the operator method, we derive the Green’s functions of the Dirac and Klein-Gordon equations in the Coulomb potential-Z?/r for an arbitrary space dimensionality d. Nonrelativistic and semiclassical asymptotic forms of these Green’s functions are considered in detail.

395

Existence of a Hydrogen Sulfide:Ferric Ion Oxidoreductase in Iron-Oxidizing Bacteria  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The existence of a hydrogen sulfide:ferric ion oxidoreductase, which catalyzes the oxidation of elemental sulfur with ferric ions as an electron acceptor to produce ferrous and sulfite ions, was assayed with washed intact cells and cell extracts of various kinds of iron-oxidizing bacteria, such as Thiobacillus ferrooxidans 13598, 13661, 14119, 19859, 21834, 23270, and 33020 from the American Type Culture Collection, Leptospirillum ferrooxidans 2705 and 2391 from the Deutsche Sammlung von Mikr...

Sugio, Tsuyoshi; White, Kathy J.; Shute, Elizabeth; Choate, Donna; Blake, Robert C.

1992-01-01

396

Roles of thermophilic thiosulfate-reducing bacteria and methanogenic archaea in the biocorrosion of oil pipelines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Thermophilic sulfide-producing microorganisms from an oil pipeline network were enumerated with different sulfur oxyanions as electron acceptors at 55 oC. Most-probable number (MPN) analysis showed that thiosulfate-reducing bacteria were the most numerous sulfidogenic microorganisms in pipeline inspection gauge (PIG) scrapings. Thiosulfate-reducing and methanogenic enrichments were obtained from the MPN cultures that were able to use yeast extract as the electron donor. Molecular analysis r...

JosephMichaelSuflita

2014-01-01

397

Anoxic iron cycling bacteria from an iron sulfide- and nitrate-rich freshwater environment  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this study, both culture-dependent and culture-independent methods were used to determine whether the iron sulfide mineral- and nitrate-rich freshwater nature reserve Het Zwart Water accommodates anoxic microbial iron cycling. Molecular analyses (16S rRNA gene clone library and fluorescence in situ hybridization, FISH) showed that sulfur-oxidizing denitrifiers dominated the microbial population. In addition, bacteria resembling the iron-oxidizing, nitrate-reducing Acidovorax strain BrG1 ac...

SuzanneCaroline MarianneHaaijer

2012-01-01

398

Drinking Water Denitrification using Autotrophic Denitrifying Bacteria in a Fluidized Bed Bioreactor   

Digital Repository Infrastructure Vision for European Research (DRIVER)

Background and Objectives: Contamination of drinking water sources with nitrate may cause adverse effects on human health. Due to operational and maintenance problems of physicochemical nitrate removal processes, using biological denitrification processes have been performed. The aim of this study is to evaluate nitrate removal efficiency from drinking water using autotrophic denitrifying bacteria immobilized on sulfur impregnated activated carbon in a fluidized bed bioreactor. Materials and ...

Abdolmotaleb Seid-mohammadi; Hossein Movahedian Attar; Mahnaz Nikaeen

2013-01-01

399

Programmed Death in Bacteria  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Programmed cell death (PCD) in bacteria plays an important role in developmental processes, such as lysis of the mother cell during sporulation of Bacillus subtilis and lysis of vegetative cells in fruiting body formation of Myxococcus xanthus. The signal transduction pathway leading to autolysis of the mother cell includes the terminal sporulation sigma factor E?K, which induces the synthesis of autolysins CwlC and CwlH. An activator of autolysin in this and other PCD processes is yet to be...

Lewis, Kim

2000-01-01

400

Bacteria in solitary confinement.  

Science.gov (United States)

Even in clonal bacterial cultures, individual bacteria can show substantial stochastic variation, leading to pitfalls in the interpretation of data derived from millions of cells in a culture. In this issue of the Journal of Bacteriology, as part of their study on osmoadaptation in a cyanobacterium, Nanatani et al. describe employing an ingenious microfluidic device that gently cages individual cells (J Bacteriol 197:676-687, 2015, http://dx.doi.org/10.1128/JB.02276-14). The device is a welcome addition to the toolkit available to probe the responses of individual cells to environmental cues. PMID:25488297

Mullineaux, Conrad W

2015-02-15

 
 
 
 
401

Bioretention column study of bacteria community response to salt-enriched artificial stormwater.  

Science.gov (United States)

Cold climate cities with green infrastructure depend on soil bacteria to remove nutrients from road salt-enriched stormwater. Our research examined how bacterial communities in laboratory columns containing bioretention media responded to varying concentrations of salt exposure from artificial stormwater and the effect of bacteria and salt on column effluent concentrations. We used a factorial design with two bacteria treatments (sterile, nonsterile) and three salt concentrations (935, 315, and 80 ppm), including a deionized water control. Columns were repeatedly saturated with stormwater or deionized and then drained throughout 5 wk, with the last week of effluent analyzed for water chemistry. To examine bacterial communities, we extracted DNA from column bioretention media at time 0 and at week 5 and used molecular profiling techniques to examine bacterial community changes. We found that bacterial community taxa changed between time 0 and week 5 and that there was significant separation between taxa among salt treatments. Bacteria evenness was significantly affected by stormwater treatment, but there were no differences in bacterial richness or diversity. Soil bacteria and salt treatments had a significant effect on the effluent concentration of NO, PO, Cu, Pb, and Zn based on ANOVA tests. The presence of bacteria reduced effluent NO and Zn concentrations by as much as 150 and 25%, respectively, while having a mixed effect on effluent PO concentrations. Our results demonstrate how stormwater can affect bacterial communities and how the presence of soil bacteria improves pollutant removal by green infrastructure. PMID:23128752

Endreny, Theodore; Burke, David J; Burchhardt, Kathleen M; Fabian, Mark W; Kretzer, Annette M

2012-01-01

402

75 FR 32743 - Action Affecting Export Privileges; Green Supply, Inc.; Robert Leland Green and William Robert...  

Science.gov (United States)

...Privileges; Green Supply, Inc.; Robert Leland Green and William Robert Green; Order...Missouri 63382, Respondent; Robert Leland Green, 3059 Audrian Road 581, Vandalia...Section 766.23 of the Regulations: Robert Leland Green and William Robert Green,...

2010-06-09

403

Compliance for Green IT  

CERN Document Server

The growing range of Green IT regulations are challenging more and more organisations to take specific steps to ensure they are in compliance with sometimes complex regulations, ranging from cap & trade requirements through to regulations concerning IT equipment disposal.

Calder, Alan

2009-01-01

404

The Green Language  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Green is a statically-typed object-oriented language that separates subtyping from inheritance. It supports garbage collection, classes as first-class objects, parameterized classes, introspective reflection and a kind of run-time metaobjects called shells.

Guimara?es, Jose? Oliveira

2013-01-01

405

Green certificates causing inconvenience?  

International Nuclear Information System (INIS)

From early 2002, producers of green energy in selected countries have been able to benefit from generous financial support in the Netherlands. Thus, there has been increased sale of green certificates from Norway and Sweden. But the condition that physical energy delivery should accompany the certificates has caused a marked rise in the price of energy in transit through Germany to the Netherlands. This article discusses the green certificate concept and the experience gained from the Netherlands. One conclusion is that if large-scale trade with green certificates is introduced in Europe without the condition of accompanying energy delivery, then producers of hydro-electric power in Norway and Sweden may be the losers

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