WorldWideScience

Sample records for acidithiobacillus ferrooxidans metabolism

  1. Insights into the iron and sulfur energetic metabolism of Acidithiobacillus ferrooxidans by microarray transcriptome profiling

    Energy Technology Data Exchange (ETDEWEB)

    R. Quatrini; C. Appia-Ayme; Y. Denis; J. Ratouchniak; F. Veloso; J. Valdes; C. Lefimil; S. Silver; F. Roberto; O. Orellana; F. Denizot; E. Jedlicki; D. Holmes; V. Bonnefoy

    2006-09-01

    Acidithiobacillus ferrooxidans is a well known acidophilic, chemolithoautotrophic, Gram negative, bacterium involved in bioleaching and acid mine drainage. In aerobic conditions, it gains energy mainly from the oxidation of ferrous iron and/or reduced sulfur compounds present in ores. After initial oxidation of the substrate, electrons from ferrous iron or sulfur enter respiratory chains and are transported through several redox proteins to oxygen. However, the oxidation of ferrous iron and reduced sulfur compounds has also to provide electrons for the reduction of NAD(P) that is subsequently required for many metabolic processes including CO2 fixation. To help to unravel the enzymatic pathways and the electron transfer chains involved in these processes, a genome-wide microarray transcript profiling analysis was carried out. Oligonucleotides corresponding to approximately 3000 genes of the A. ferrooxidans type strain ATCC23270 were spotted onto glass-slides and hybridized with cDNA retrotranscribed from RNA extracted from ferrous iron and sulfur grown cells. The genes which are preferentially transcribed in ferrous iron conditions and those preferentially transcribed in sulfur conditions were analyzed. The expression of a substantial number of these genes has been validated by real-time PCR, Northern blot hybridization and/or immunodetection analysis. Our results support and extend certain models of iron and sulfur oxidation and highlight previous observations regarding the possible presence of alternate electron pathways. Our findings also suggest ways in which iron and sulfur oxidation may be co-ordinately regulated. An accompanying paper (Appia-Ayme et al.) describes results pertaining to other metabolic functions.

  2. Bioleaching of zinc from gold ores using Acidithiobacillus ferrooxidans

    Institute of Scientific and Technical Information of China (English)

    Pakawadee Kaewkannetra; Francisco Jose Garcia-Garcia; Tze Yen Chiu

    2009-01-01

    that Acidithiobacillus ferrooxidans can successfully leach zinc by as much as 6 times compared with the control experiment (without Acidithiobacillus ferrooxidans ferrooxidans). The maximum efficiency (92.3%) for microbial leaching is obtained in

  3. The role of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans in arsenic bioleaching from soil.

    Science.gov (United States)

    Ko, Myoung-Soo; Park, Hyun-Sung; Kim, Kyoung-Woong; Lee, Jong-Un

    2013-12-01

    Bioleaching of As from the soil in an abandoned Ag-Au mine was carried out using Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans. A. ferrooxidans is an iron oxidizer and A. thiooxidans is a sulfur oxidizer. These two microbes are acidophilic and chemoautotrophic microbes. Soil samples were collected from the Myoungbong and Songcheon mines. The main contaminant of the soil was As, with an average concentration of 4,624 mg/kg at Myoungbong and 5,590 mg/kg at Songcheon. A. ferrooxidans and A. thiooxidans generated lower pH conditions during their metabolism process. The bioleaching of As from soil has a higher removal efficiency than chemical leaching. A. ferrooxidans could remove 70 % of the As from the Myoungbong and Songcheon soils; however, A. thiooxidans extracted only 40 % of the As from the Myoungbong soil. This study shows that bioleaching is an effective process for As removal from soil.

  4. Preparation of jarosite by Acidithiobacillus ferrooxidans oxidation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The formation of jarosite in the presence of Acidithiobacillus ferrooxidans (A. ferrooxidans) was researched to ascertain the conditions of producing minimum precipitation. The effects of salt concentration and pH on the characteristics of jarosite formed in K.2S(V(NH4)2SO4-FeSO4 inorganic salt solution and 9K medium were studied by using the measurements of scanning electron microscope, X-ray diffraction, Fourierism transform infrared analysis, thermogravity/differential thermogravity analysis and particle size analysis to evaluate the product. The results indicate that the formation of jarosite begins when A. ferrooxidans reaches logarithmic growth phase in 9K medium, and a higher pH value is beneficial to the formation of jarosite. The jarosite formed in 9K medium has smaller and more concentrative particle size and smoother surface than that formed in inorganic salt solution.

  5. Pyrite oxidation by Acidithiobacillus ferrooxidans bacteria

    Directory of Open Access Journals (Sweden)

    Savić Dragiša S.

    2005-01-01

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

  6. Adhesion forces between cells of Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans or Leptospirillum ferrooxidans and chalcopyrite.

    Science.gov (United States)

    Zhu, Jianyu; Li, Qian; Jiao, Weifeng; Jiang, Hao; Sand, Wolfgang; Xia, Jinlan; Liu, Xueduan; Qin, Wenqing; Qiu, Guanzhou; Hu, Yuehua; Chai, Liyuan

    2012-06-01

    The efficiency of copper leaching is improved by bacteria attached to chalcopyrite. Therefore, the study of the attachment mechanism to control leaching is important. The adhesion of three species of leaching microorganisms including Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans and Leptospirillum ferrooxidans to chalcopyrite was investigated by using atomic force microscopy (AFM). The forces were measured with tip-immobilized cells approached to and retracted from the mineral. The results show that both the surface charge and the hydrophobicity of bacteria cells influence the adhesion force. Furthermore, the adhesion force decreased in case the extracellular polymeric substances (EPS) had been removed. In addition, the data indicate that the amount of attached cells increased with increasing adhesion force.

  7. Arsenic Precipitation in the Bioleaching of Realgar Using Acidithiobacillus ferrooxidans

    Directory of Open Access Journals (Sweden)

    Peng Chen

    2013-01-01

    Full Text Available The current study investigates the characteristics of arsenic precipitation during the bioleaching of realgar. The bioleaching performance of Acidithiobacillus ferrooxidans BY-3 (A. ferrooxidans was investigated through scanning electron microscopy (SEM, transmission electron microscopy (TEM, X-ray diffraction (XRD, and Fourier transform infrared (FT-IR spectrophotometry. SEM and XRD analyses revealed that the arsenic-adapted strain of A. ferrooxidans was more hydrophobic and showed higher attachment efficiency to realgar compared with the wild strain. The arsenic precipitation using A. ferrooxidans resulted in the precipitation of an arsenic-rich compound on the surface of the bacterial cell, as shown in the TEM images. The FT-IR spectra suggested that the −OH and −NH groups were closely involved in the biosorption process. The observations above strongly suggest that the cell surface of A. ferrooxidans plays a role in the induction of arsenic tolerance during the bioleaching of realgar.

  8. Bioleaching of marmatite flotation concentrate by Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans

    Institute of Scientific and Technical Information of China (English)

    石绍渊; 方兆珩

    2004-01-01

    Bioleaching of marmatite flotation concentrate by Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans was investigated at 35 ℃, the initial pH value of 2.0 on an orbital shaker with 160 min-1 over a period of 10 days. Experimental results indicate that the adapted strains increase markedly the dissolution rate and the leaching ratio of marmatite. Pulp density also affects the bioleaching of marmatite. Massive elemental sulfur and jarosite form during the leaching process in the systems inoculating the adapted strains in pure and mixed cultures; and acid product is enhanced, which decreases the pH below to 2.0 in latter leaching period. Marmatite preferentially dissolves during the bacterial leaching of complex sulfides. Compared with the pure cultures of original and adapted strains, the adapted strains of Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans in mixed cultures are more efficient in the oxidation of marmatite.

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

    Science.gov (United States)

    Martínez, Patricio; Gálvez, Sebastián; Ohtsuka, Norimasa; Budinich, Marko; Cortés, María Paz; Serpell, Cristián; Nakahigashi, Kenji; Hirayama, Akiyoshi; Tomita, Masaru; Soga, Tomoyoshi; Martínez, Servet; Maass, Alejandro; Parada, Pilar

    2013-02-01

    In this study, we present the first metabolic profiles for two bioleaching bacteria using capillary electrophoresis coupled with mass spectrometry. The bacteria, Acidithiobacillus ferrooxidans strain Wenelen (DSM 16786) and Acidithiobacillus thiooxidans strain Licanantay (DSM 17318), were sampled at different growth phases and on different substrates: the former was grown with iron and sulfur, and the latter with sulfur and chalcopyrite. Metabolic profiles were scored from planktonic and sessile states. Spermidine was detected in intra- and extracellular samples for both strains, suggesting it has an important role in biofilm formation in the presence of solid substrate. The canonical pathway for spermidine synthesis seems absent as its upstream precursor, putrescine, was not present in samples. Glutathione, a catalytic activator of elemental sulfur, was identified as one of the most abundant metabolites in the intracellular space in A. thiooxidans strain Licanantay, confirming its participation in the sulfur oxidation pathway. Amino acid profiles varied according to the growth conditions and bioleaching species. Glutamic and aspartic acid were highly abundant in intra- and extracellular extracts. Both are constituents of the extracellular matrix, and have a probable role in cell detoxification. This novel metabolomic information validates previous knowledge from in silico metabolic reconstructions based on genomic sequences, and reveals important biomining functions such as biofilm formation, energy management and stress responses. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11306-012-0443-3) contains supplementary material, which is available to authorized users.

  10. Bioleaching of metals from printed wire boards by Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans and their mixture.

    Science.gov (United States)

    Wang, Jingwei; Bai, Jianfeng; Xu, Jinqiu; Liang, Bo

    2009-12-30

    Bioleaching processes were used to mobilize metals from printed wire boards (PWBs). The bacteria Acidithiobacillus ferrooxidans (A. ferrooxidans) and Acidithiobacillus thiooxidans (A. thiooxidans) isolated from an acidic mine drainage were grown and acclimated in presence of PWBs and then used as bioleaching bacteria to solubilize metals from PWBs. The experimental results demonstrate that all the percentages of copper, lead, zinc solubilized into the leaching solution from actual PWBs basically increased with decrease of sieve fraction of sample and decrease of PWBs concentration. The concentration of PWBs should be controlled under the range from 7.8 to 19.5 g l(-1). Under 7.8 g l(-1) of the concentration of PWBs, the percentages of copper solubilized are 99.0%, 74.9%, 99.9% at 0.5-1.0mm of sieve fraction at 9 d of leaching time by the pure culture of A. ferrooxidans, the pure culture of A. thiooxidans, and mixed culture of A. ferrooxidans and A. thiooxidans, respectively, while the percentages of copper, lead and zinc solubilized are all more than 88.9% at thiooxidans were able to grow in the presence of PWBs and the pure culture of A. ferrooxidans, and the mixed culture of A. ferrooxidans and A. thiooxidans can not only efficiently bioleach the main metal copper but also bioleach other minor metals such as lead, zinc as well.

  11. Reduction of vanadium(V) with Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans.

    Science.gov (United States)

    Bredberg, Katarina; Karlsson, Hans T; Holst, Olle

    2004-03-01

    Biotechnological leaching has been proposed as a suitable method for extraction of vanadium from spent catalysts and oil ash. In the biological leaching process, the vanadium(V) can be reduced to vanadium(IV), which is a less toxic and more soluble form of the vanadium. The present investigation showed that Acidithiobacillus ferrooxidans efficiently reduced vanadium(V) in the form of vanadium pentaoxide, to vanadyl(IV) ions, and tolerated high concentrations of vanadium(IV) and vanadium(V). A. ferrooxidans was compared with Acidithiobacillus thiooxidans, which has previously been utilized for vanadium leaching and reduction. Vanadium pentaoxide and sodium vanadate were used as model compounds. The results of this study indicate possibilities to develop an economical and technically feasible process for biotechnological vanadium recovery.

  12. Biocompatibility evaluation of magnetosomes formed by Acidithiobacillus ferrooxidans

    Energy Technology Data Exchange (ETDEWEB)

    Yan Lei [Institute of Microbiology, School of Life Sciences, Lanzhou University, Lanzhou, 730000 (China); College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, 163319 (China); Yue Xiaoxuan [Institute of Microbiology, School of Life Sciences, Lanzhou University, Lanzhou, 730000 (China); Zhang Shuang [College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, 163319 (China); Chen Peng [Institute of Microbiology, School of Life Sciences, Lanzhou University, Lanzhou, 730000 (China); GIBT, Gansu Institute of Business and Technology, Yannan Road 18, Lanzhou, 730010 (China); Xu Zhiliang; Li Yang [Institute of Microbiology, School of Life Sciences, Lanzhou University, Lanzhou, 730000 (China); Li Hongyu, E-mail: hekouyanlei@gmail.com [Institute of Microbiology, School of Life Sciences, Lanzhou University, Lanzhou, 730000 (China)

    2012-10-01

    Magnetite nanocrystal has been extensively used in biomedical field. Currently, an interesting alternative to synthetic magnetic Fe{sub 3}O{sub 4} nanoparticles, called magnetosome, has been found in magnetotactic bacteria. It has been reported that Acidithiobacillus ferrooxidans (At. ferrooxidans) has a potential to synthesize magnetosome. In this study, transmission electron microscope (TEM) was used to analyze the magnetite particles in At. ferrooxidans BY-3. The magnetosomes formed by this bacterium were isolated by a method combining ultracentrifugation and magnetic separation. Crystalline phase and surface functional group of the magnetosomes were investigated by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR), respectively. Biocompatibility of the magnetosomes was systematically evaluated at various concentrations (0.5, 1.0, 2.0 and 4.0 mg/ml). MTT test, hemolysis assay and Micronucleus Test were carried out to evaluate in vitro cytotoxicity, blood toxicity and genotoxicity of magnetosomes, respectively. Under these conditions, magnetosomes showed no cytotoxic, genotoxic and hemolytic effects up to 4.0 mg/ml indicating good biocompatibility of these biological nanoparticles. These revealed that the magnetosomes might have a potential for biotechnological and biomedical applications in the future. - Highlights: Black-Right-Pointing-Pointer The production of magnetosomes from At. ferrooxidans has been easily available. Black-Right-Pointing-Pointer Several techniques are used to characterize properties of the magnetosomes. Black-Right-Pointing-Pointer The magnetosomes have no cytotoxicity, no hemolysis activity and no genotoxicity.

  13. Dynamic corrosion of copper-nickel sulfide by Acidithiobacillus ferrooxidans

    Institute of Scientific and Technical Information of China (English)

    TONG Lin-lin; JIANG Mao-fa; YANG Hong-ying; YU Juan; FAN You-jing; ZHANG Yao

    2009-01-01

    The dynamic corrosion process of bio-oxidation of copper-nickel sulfide from Karatungk in northern Xinjiang Province of China was studied. The polished wafer of the copper-nickel sulphide was used to carry on a series of oxidation corrosion experiment by Acidithiobacillus ferrooxidans. The changes of superficial corrosion appearance and the mineral dynamic corrosion process were discovered by microscope observation. Then, the galvanic cell model was established, and the bio-oxidation activation order of typical copper-nickel sulphide minerals was ascertained as pyrrhotite>pentlandite>chalocopyrite.

  14. Engineering the iron-oxidizing chemolithoautotroph Acidithiobacillus ferrooxidans for biochemical production.

    Science.gov (United States)

    Kernan, Timothy; Majumdar, Sudipta; Li, Xiaozheng; Guan, Jingyang; West, Alan C; Banta, Scott

    2016-01-01

    There is growing interest in developing non-photosynthetic routes for the conversion of CO2 to fuels and chemicals. One underexplored approach is the transfer of energy to the metabolism of genetically modified chemolithoautotrophic bacteria. Acidithiobacillus ferrooxidans is an obligate chemolithoautotroph that derives its metabolic energy from the oxidation of iron or sulfur at low pH. Two heterologous biosynthetic pathways have been expressed in A. ferrooxidans to produce either isobutyric acid or heptadecane from CO2 and the oxidation of Fe(2+). A sevenfold improvement in productivity of isobutyric acid was obtained through improved media formulations in batch cultures. Steady-state efficiencies were lower in continuous cultures, likely due to ferric inhibition. If coupled to solar panels, the photon-to-fuel efficiency of this proof-of-principle process approaches estimates for agriculture-derived biofuels. These efforts lay the foundation for the utilization of this organism in the exploitation of electrical energy for biochemical synthesis.

  15. Stochastic simulation of growth curves of Acidithiobacillus ferrooxidans

    Institute of Scientific and Technical Information of China (English)

    YANG Yu; PENG Hong; QIU Guan-zhou; LIU Jian-she; HU Yue-hua

    2006-01-01

    To reveal the low growth rate of Acidithiobacillus ferrooxidans, a stochastic growth model was proposed to analyze growth curves of these bacteria in a batch culture. An algorithm was applied to simulate the bacteria population during lag and exponential phase. The results show that the model moderately fits the experimental data.Further, the mean growth constant (K) of growth curves is obtained by fitting the logarithm of the simulating population data versus the generation numbers with the different initial population number (N0) and initial mean activity of population (A0). When N0 is 300 and 700 respectively, the discrepancy of K value is only 0.91%, however, A0 is 0.34 and 0.38 respectively, the discrepancy of K value is 19.53%. It suggests that the effect of A0 on the lag phase exceeds N0, though both parameters could shorten the lag phase by increasing their values.

  16. Sulfur activation-related extracellular proteins of Acidithiobacillus ferrooxidans

    Institute of Scientific and Technical Information of China (English)

    ZHANG Cheng-gui; ZHANG Rui-yong; XIA Jin-lan; ZHANG Qian; NIE Zhen-yuan

    2008-01-01

    The fractions of the extracellular proteins of Acidithiobacillus ferrooxidans grown on two different energy substrates,elemental sulfur and ferrous sulfate,were selectively prepared with hot water treatment and distinctly shown by two-dimensional gel electrophoresis.Some protein spots with apparently higher abundance in sulfur energy substrate than in ferrous sulfate energy substrate were identified by using MALDI-TOF/TOF.Based on peptide mass fingerprints and bioinformatical analysis,the extracellular proteins were classified according to their functions as conjugal transfer protein,pilin,vacJ lipoprotein,polysaccharide deacetylase family protein,Ser/Thr protein phosphatase family protein and hypothetical proteins.Several extracellular proteins were found abundant in thiol groups and with CXXC functional motif,these proteins may be directly involved in the sulfur activation by use of their thiol group (Pr-SH) to bond the elemental sulfur.

  17. The effects of Acidithiobacillus ferrooxidans on the leaching of cobalt and strontium adsorbed onto soil particles.

    Science.gov (United States)

    Park, Hyun-Sung; Lee, Jong-Un; Ahn, Jae-Woo

    2007-08-01

    Bioleaching from soil artificially contaminated with analogues of radionuclides, Co and Sr, was carried out using a Fe-oxidizing bacterium, Acidithiobacillus ferrooxidans. Due to bacterial metabolism, the pH and dissolved Fe(3+) concentration in a biotic slurry decreased and increased respectively, over time, but the concentrations of Co and Sr extracted from the soil showed no significant enhancement compared with those under abiotic control. In both cases, Co and Sr were leached from the soil during the initial period of the experiment, due to the initially low solution pH of 2.0, and the dissolved concentrations remained almost constant for the duration of the experiment (300 h). Since oxidation of Fe(2+) by A. ferrooxidans led to the production of Fe precipitates and colloidal suspensions, the Co and Sr extracted into solution were most likely re-adsorbed onto the Fe solids. Also, A. ferrooxidans, without an external supply of Fe(2+), extracted almost equal or greater amounts of Co and Sr from the soil than when Fe(2+) was supplied. Under the same leaching conditions, the extent of Sr removal was much lower than that of Co. On the contrary to the high efficiency of microbial metal leaching in biohydrometallurgy for low-graded sulfide ores, which has been widely documented, conventional bioleaching techniques with A. ferrooxidans supplied with enough Fe(2+) showed low efficiency for the removal of radionuclides loosely bound onto soil particle surfaces.

  18. Bioleaching of sphalerite by Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans cultured in 9K medium modified with pyrrhotite

    Institute of Scientific and Technical Information of China (English)

    CHEN Song; QIU Guan-zhou; QIN Wen-qing; LAN Zhuo-yue

    2008-01-01

    Elective culture of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans in 9K medium modified with pyrrhotite was studied. Bioleaching of flotation concentrate of sphalerite by the selected bacteria was carried out. The results show that the microorganisms cultured by pyrrhotite are a mixture of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans, of which the capability to oxidize ferrous to ferric irons is enhanced by the high mass ratio of Fe to S in pyrrhotite. Three pyrrhotite samples were separated into various parts with corresponding S/Fe ratios by magnetic separation and were used to culture the elective bacteria as the substrate. The association of the cultures could provide a more rapid and complete oxidation of sphalerite than that of bacteria cultivated by conventional methods.

  19. Immobilization of Acidithiobacillus ferrooxidans and ferric iron production

    Institute of Scientific and Technical Information of China (English)

    ZHOU Hong-bo; LIU Xi; QIU Guan-zhou; LIU Jian-she; CHEN Xin-hua

    2006-01-01

    Cobblestone, glass beads and active carbon were selected as bacterial supports to study immobilization of Acidithiobacillus ferrooxidans in packed bed reactors. The production of ferric iron was then investigated in these immobilized reactors in batch and continuous operation modes. The results show that stable biofilm forms in cobblestone and active carbon supports, thus these two kinds of supports are suitable for immobilization of A. ferrooxidans. In batch culture, ferric iron productivity in reactor with cobblestone as supports is 0.61 g/(L·h), which is 1.49 times higher than that in suspended culture reactor. In continuous operation mode, the maximum ferric iron productivity in reactor with cobblestone as supports is 1.54 g/(Lh), which is 3.76 times higher than that in suspended culture reactor. The maximum ferric iron productivity in reactor with active carbon as supports is 1.89 g/(L·h), which is 4.61 times higher than that in suspended culture reactor. In addition to bacteria, the results of X-ray diffraction and scanning electronic microscope analysis show that there is a lot of exopolysaccharide, jarosite and ammoniojarosite in biofilm, which plays important role in the formation ofbiofilm.

  20. Comparative genomic analysis of Acidithiobacillus ferrooxidans strains using the A. ferrooxidans ATCC 23270 whole-genome oligonucleotide microarray.

    Science.gov (United States)

    Luo, Hailang; Shen, Li; Yin, Huaqun; Li, Qian; Chen, Qijiong; Luo, Yanjie; Liao, Liqin; Qiu, Guanzhou; Liu, Xueduan

    2009-05-01

    Acidithiobacillus ferrooxidans is an important microorganism used in biomining operations for metal recovery. Whole-genomic diversity analysis based on the oligonucleotide microarray was used to analyze the gene content of 12 strains of A. ferrooxidans purified from various mining areas in China. Among the 3100 open reading frames (ORFs) on the slides, 1235 ORFs were absent in at least 1 strain of bacteria and 1385 ORFs were conserved in all strains. The hybridization results showed that these strains were highly diverse from a genomic perspective. The hybridization results of 4 major functional gene categories, namely electron transport, carbon metabolism, extracellular polysaccharides, and detoxification, were analyzed. Based on the hybridization signals obtained, a phylogenetic tree was built to analyze the evolution of the 12 tested strains, which indicated that the geographic distribution was the main factor influencing the strain diversity of these strains. Based on the hybridization signals of genes associated with bioleaching, another phylogenetic tree showed an evolutionary relationship from which the co-relation between the clustering of specific genes and geochemistry could be observed. The results revealed that the main factor was geochemistry, among which the following 6 factors were the most important: pH, Mg, Cu, S, Fe, and Al.

  1. Ex-situ bioremediation of U(VI from contaminated mine water using Acidithiobacillus ferrooxidans strains

    Directory of Open Access Journals (Sweden)

    Maria eRomero-Gonzalez

    2016-05-01

    Full Text Available The ex-situ bioremoval of U(VI from contaminated water using Acidithiobacillus ferrooxidans strain 8455 and 13538 was studied under a range of pH and uranium concentrations. The effect of pH on the growth of bacteria was evaluated across the range 1.5 – 4.5 pH units. The respiration rate of At. ferrooxidans at different U(VI concentrations was quantified as a measure of the rate of metabolic activity over time using an oxygen electrode. The biosorption process was quantified using a uranyl nitrate solution, U-spiked growth media and U-contaminated mine water. The results showed that both strains of At. ferrooxidans are able to remove U(VI from solution at pH 2.5 – 4.5, exhibiting a buffering capacity at pH 3.5. The respiration rate of the micro-organism was affected at U(VI concentration of 30 mg L-1. The kinetics of the sorption fitted a pseudo-first order equation, and depended on the concentration of U(VI. The KD obtained from the biosorption experiments indicated that strain 8455 is more efficient for the removal of U(VI. A bioreactor designed to treat a solution of 100 mg U(VI L-1 removed at least 50% of the U(VI in water. The study demonstrated that At. ferrooxidans can be used for the ex-situ bioremediation of U(VI contaminated mine water.

  2. Effect of surfactant Tween-80 on sulfur oxidation and expression of sulfur metabolism relevant genes of Acidithiobacillus ferrooxidans%表面活性剂Tween-80对Acidithiobacillus ferrooxidans硫氧化和硫代谢相关蛋白质基因表达的影响

    Institute of Scientific and Technical Information of China (English)

    彭安安; 刘红昌; 聂珍媛; 夏金兰

    2012-01-01

    研究了表面活性剂Tween-80对Acidithiobacillus ferrooxidans ATCC 23270生长、硫氧化和硫代谢相关典型基因表达的影响.结果表明,当培养基中含有10-2 g/L Tween-80时,A.ferrooxidans的生长以及其对不溶性底物(S0和CuFeS2)的代谢得到了促进.在该条件下,经过24 d的生物浸出,黄铜矿的铜离子浸出率比对照组(不含Tween-80)高16%.FT-IR光谱分析表明,这可能是由于Tween-80的存在而导致胞外多聚物成分发生变化而引起的.用RT-qPCR来分析17个硫代谢相关基因在Tween-80存在时的表达差异.胞外蛋白质基因表达下调表明了Tween-80对细菌一硫吸附作用的影响.硫代谢相关酶基因表达水平的变化为硫代谢的研究提供了参考.%The effects of surfactant Tween-80 on the growth,sulfur oxidation,and expression of selected typical sulfur metabolism relevant genes of Acidithiobacillus ferrooxidans ATCC 23270 were investigated.The results showed that in the presence of 10-2 g/L Tween-80,the growth of A.ferrooxidans and its metabolism on the insoluble substrate S0 and CuFeS2 were promoted.After 24 d of bioleaching,the copper extraction yield of chalcopyrite at 10-2 g/L Tween-80 increased by 16% compared with the bioleaching experiment without Tween-80.FT-IR spectra analysis revealed that the result was probably caused by the extracellular polymeric substances whose composition could be changed by the surfactant addition.RT-qPCR was used to analyze the differential expressions of 17 selected sulfur metabolism relevant genes in response to the addition of Tween-80.Down-regulation of the extracellular protein genes indicated the influence of Tween-80 on bacteria-sulfur adsorption.Variation of the expression level of the enzymes provided a supplement to sulfur metabolism investigation.

  3. Molecular characterization of Acidithiobacillus ferrooxidans and A. thiooxidans strains isolated from mine wastes in Brazil.

    Science.gov (United States)

    Paulino, L C; Bergamo, R F; Garcia, O; de Mello, M P; Manfio, G P; Ottoboni, L M

    2001-10-01

    Nineteen strains of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans, including 12 strains isolated from coal, copper, gold and uranium mines in Brazil, strains isolated from similar sources in other countries and the type strains of the two species were characterized together with the type strain of A. caldus by using a combination of molecular systematic methods, namely ribotyping, BOX- and ERIC-PCR and DNA-DNA hybridization assays. Data derived from the molecular fingerprinting analyses showed that the tested strains encompassed a high degree of genetic variability. Two of the Brazilian A. ferrooxidans organisms (strains SSP and PCE) isolated from acid coal mine waste and uranium mine effluent, respectively, and A. thiooxidans strain DAMS, isolated from uranium mine effluent, were the most genetically divergent organisms. The DNA-DNA hybridization data did not support the allocation of Acidithiobacillus strain SSP to the A. ferrooxidans genomic species, as it shared only just over 40% DNA relatedness with the type strain of the species. Acidithiobacillus strain SSP was not clearly related to A. ferrooxidans in the 16S rDNA tree.

  4. Extending the models for iron and sulfur oxidation in the extreme Acidophile Acidithiobacillus ferrooxidans

    Directory of Open Access Journals (Sweden)

    Holmes David S

    2009-08-01

    Full Text Available Abstract Background Acidithiobacillus ferrooxidans gains energy from the oxidation of ferrous iron and various reduced inorganic sulfur compounds at very acidic pH. Although an initial model for the electron pathways involved in iron oxidation has been developed, much less is known about the sulfur oxidation in this microorganism. In addition, what has been reported for both iron and sulfur oxidation has been derived from different A. ferrooxidans strains, some of which have not been phylogenetically characterized and some have been shown to be mixed cultures. It is necessary to provide models of iron and sulfur oxidation pathways within one strain of A. ferrooxidans in order to comprehend the full metabolic potential of the pangenome of the genus. Results Bioinformatic-based metabolic reconstruction supported by microarray transcript profiling and quantitative RT-PCR analysis predicts the involvement of a number of novel genes involved in iron and sulfur oxidation in A. ferrooxidans ATCC23270. These include for iron oxidation: cup (copper oxidase-like, ctaABT (heme biogenesis and insertion, nuoI and nuoK (NADH complex subunits, sdrA1 (a NADH complex accessory protein and atpB and atpE (ATP synthetase F0 subunits. The following new genes are predicted to be involved in reduced inorganic sulfur compounds oxidation: a gene cluster (rhd, tusA, dsrE, hdrC, hdrB, hdrA, orf2, hdrC, hdrB encoding three sulfurtransferases and a heterodisulfide reductase complex, sat potentially encoding an ATP sulfurylase and sdrA2 (an accessory NADH complex subunit. Two different regulatory components are predicted to be involved in the regulation of alternate electron transfer pathways: 1 a gene cluster (ctaRUS that contains a predicted iron responsive regulator of the Rrf2 family that is hypothesized to regulate cytochrome aa3 oxidase biogenesis and 2 a two component sensor-regulator of the RegB-RegA family that may respond to the redox state of the quinone pool

  5. Extending the models for iron and sulfur oxidation in the extreme Acidophile Acidithiobacillus ferrooxidans

    Science.gov (United States)

    2009-01-01

    Background Acidithiobacillus ferrooxidans gains energy from the oxidation of ferrous iron and various reduced inorganic sulfur compounds at very acidic pH. Although an initial model for the electron pathways involved in iron oxidation has been developed, much less is known about the sulfur oxidation in this microorganism. In addition, what has been reported for both iron and sulfur oxidation has been derived from different A. ferrooxidans strains, some of which have not been phylogenetically characterized and some have been shown to be mixed cultures. It is necessary to provide models of iron and sulfur oxidation pathways within one strain of A. ferrooxidans in order to comprehend the full metabolic potential of the pangenome of the genus. Results Bioinformatic-based metabolic reconstruction supported by microarray transcript profiling and quantitative RT-PCR analysis predicts the involvement of a number of novel genes involved in iron and sulfur oxidation in A. ferrooxidans ATCC23270. These include for iron oxidation: cup (copper oxidase-like), ctaABT (heme biogenesis and insertion), nuoI and nuoK (NADH complex subunits), sdrA1 (a NADH complex accessory protein) and atpB and atpE (ATP synthetase F0 subunits). The following new genes are predicted to be involved in reduced inorganic sulfur compounds oxidation: a gene cluster (rhd, tusA, dsrE, hdrC, hdrB, hdrA, orf2, hdrC, hdrB) encoding three sulfurtransferases and a heterodisulfide reductase complex, sat potentially encoding an ATP sulfurylase and sdrA2 (an accessory NADH complex subunit). Two different regulatory components are predicted to be involved in the regulation of alternate electron transfer pathways: 1) a gene cluster (ctaRUS) that contains a predicted iron responsive regulator of the Rrf2 family that is hypothesized to regulate cytochrome aa3 oxidase biogenesis and 2) a two component sensor-regulator of the RegB-RegA family that may respond to the redox state of the quinone pool. Conclusion

  6. Bioleaching of chalcopyrite concentrate using Leptospirillum ferriphilum, Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans in a continuous bubble column reactor.

    Science.gov (United States)

    Xia, Lexian; Yin, Chu; Dai, Songlin; Qiu, Guanzhou; Chen, Xinhua; Liu, Jianshe

    2010-03-01

    To estimate the bioleaching performance of chalcopyrite for various hydraulic residence times (HRTs), laboratory-scale bioleaching of chalcopyrite concentrate was carried out in a continuous bubble column reactor with three different HRTs of 120, 80 and 40 h, respectively. An extraction rate and ratio of 0.578 g Cu l(-1) h(-1) and 39.7%, respectively, were achieved for an HRT of 80 h at a solids concentration of 10% (w/v). Lower bioleaching performances than this were obtained for a longer HRT of 120 h and a shorter HRT of 40 h. In addition, there was obvious competition between Leptospirillum ferriphilum and Acidithiobacillus ferrooxidans to oxidize ferrous iron, causing large compositional differences between the microbial communities obtained for the different HRTs. Leptospirillum ferriphilum and Acidithiobacillus thiooxidans were found to be the dominant microbes for the longer HRT (120 h). Acidithiobacillus ferrooxidans became the dominant species when the HRT was decreased. The proportion of Acidithiobacillus thiooxidans was comparatively constant in the microbial community throughout the three process stages.

  7. Purification and enzymatic characteristics of cysteine desulfurase, IscS, in Acidithiobacillus ferrooxidans ATCC 23270

    Institute of Scientific and Technical Information of China (English)

    WU An-na; ZHANG Yan-fei; ZHENG Chun-li; DAI Yun-jie; LIU Yuan-dong; ZENG Jia; GU Guo-hua; LIU Jian-she

    2008-01-01

    A cysteine desulfurase protein,IscS,was encoded by the operon iscSUA in Acidithiobacillus ferrooxidans.The gene of IscS from Acidithiobacillus ferrooxidans ATCC 23270 was cloned and expressed in Escherichia coli.The protein was purified by one-step affinity chromatography to homogeneity.The final protein yield after affinity chromatography was 12.9%.The enzyme was characterized for thermal stability,pH and kinetic parameters.The molecular mass of recombinant IscS was 46 ku by SDS-PAGE.The optimum pH was 8.0-8.5.The enzyme had a temperature optimum at 30 ℃ and was relatively stable at 40 ℃,with 67% loss of activity.1,5-I-AEDANS significantly inhibited IscS activity.Kinetic parameters Km and Vmax were found to be 0.11 mmol/L and 2.57 μmol/(L-min).

  8. Type IV pili of Acidithiobacillus ferrooxidans can transfer electrons from extracellular electron donors.

    Science.gov (United States)

    Li, Yongquan; Li, Hongyu

    2014-03-01

    Studies on Acidithiobacillus ferrooxidans accepting electrons from Fe(II) have previously focused on cytochrome c. However, we have discovered that, besides cytochrome c, type IV pili (Tfp) can transfer electrons. Here, we report conduction by Tfp of A. ferrooxidans analyzed with a conducting-probe atomic force microscope (AFM). The results indicate that the Tfp of A. ferrooxidans are highly conductive. The genome sequence of A. ferrooxidans ATCC 23270 contains two genes, pilV and pilW, which code for pilin domain proteins with the conserved amino acids characteristic of Tfp. Multiple alignment analysis of the PilV and PilW (pilin) proteins indicated that pilV is the adhesin gene while pilW codes for the major protein element of Tfp. The likely function of Tfp is to complete the circuit between the cell surface and Fe(II) oxides. These results indicate that Tfp of A. ferrooxidans might serve as biological nanowires transferring electrons from the surface of Fe(II) oxides to the cell surface. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. The small heat shock proteins from Acidithiobacillus ferrooxidans: gene expression, phylogenetic analysis, and structural modeling

    Directory of Open Access Journals (Sweden)

    Ribeiro Daniela A

    2011-12-01

    Full Text Available Abstract Background Acidithiobacillus ferrooxidans is an acidophilic, chemolithoautotrophic bacterium that has been successfully used in metal bioleaching. In this study, an analysis of the A. ferrooxidans ATCC 23270 genome revealed the presence of three sHSP genes, Afe_1009, Afe_1437 and Afe_2172, that encode proteins from the HSP20 family, a class of intracellular multimers that is especially important in extremophile microorganisms. Results The expression of the sHSP genes was investigated in A. ferrooxidans cells submitted to a heat shock at 40°C for 15, 30 and 60 minutes. After 60 minutes, the gene on locus Afe_1437 was about 20-fold more highly expressed than the gene on locus Afe_2172. Bioinformatic and phylogenetic analyses showed that the sHSPs from A. ferrooxidans are possible non-paralogous proteins, and are regulated by the σ32 factor, a common transcription factor of heat shock proteins. Structural studies using homology molecular modeling indicated that the proteins encoded by Afe_1009 and Afe_1437 have a conserved α-crystallin domain and share similar structural features with the sHSP from Methanococcus jannaschii, suggesting that their biological assembly involves 24 molecules and resembles a hollow spherical shell. Conclusion We conclude that the sHSPs encoded by the Afe_1437 and Afe_1009 genes are more likely to act as molecular chaperones in the A. ferrooxidans heat shock response. In addition, the three sHSPs from A. ferrooxidans are not recent paralogs, and the Afe_1437 and Afe_1009 genes could be inherited horizontally by A. ferrooxidans.

  10. Transcriptional and functional studies of Acidithiobacillus ferrooxidans genes related to survival in the presence of copper.

    Science.gov (United States)

    Navarro, Claudio A; Orellana, Luis H; Mauriaca, Cecilia; Jerez, Carlos A

    2009-10-01

    The acidophilic Acidithiobacillus ferrooxidans can resist exceptionally high copper (Cu) concentrations. This property is important for its use in biomining processes, where Cu and other metal levels range usually between 15 and 100 mM. To learn about the mechanisms that allow A. ferrooxidans cells to survive in this environment, a bioinformatic search of its genome showed the presence of at least 10 genes that are possibly related to Cu homeostasis. Among them are three genes coding for putative ATPases related to the transport of Cu (A. ferrooxidans copA1 [copA1(Af)], copA2(Af), and copB(Af)), three genes related to a system of the resistance nodulation cell division family involved in the extraction of Cu from the cell (cusA(Af), cusB(Af), and cusC(Af)), and two genes coding for periplasmic chaperones for this metal (cusF(Af) and copC(Af)). The expression of most of these open reading frames was studied by real-time reverse transcriptase PCR using A. ferrooxidans cells adapted for growth in the presence of high concentrations of Cu. The putative A. ferrooxidans Cu resistance determinants were found to be upregulated when this bacterium was exposed to Cu in the range of 5 to 25 mM. These A. ferrooxidans genes conferred to Escherichia coli a greater Cu resistance than wild-type cells, supporting their functionality. The results reported here and previously published data strongly suggest that the high resistance of the extremophilic A. ferrooxidans to Cu may be due to part or all of the following key elements: (i) a wide repertoire of Cu resistance determinants, (ii) the duplication of some of these Cu resistance determinants, (iii) the existence of novel Cu chaperones, and (iv) a polyP-based Cu resistance system.

  11. Bioflotation of sulfide minerals with Acidithiobacillus ferrooxidans in relation to copper activation and surface oxidation.

    Science.gov (United States)

    Pecina-Treviño, E T; Ramos-Escobedo, G T; Gallegos-Acevedo, P M; López-Saucedo, F J; Orrantia-Borunda, E

    2012-08-24

    Surface oxidation of sulfides and copper (Cu) activation are 2 of the main processes that determine the efficiency of flotation. The present study was developed with the intention to ascertain the role of the phenomena in the biomodification of sulfides by Acidithiobacillus ferrooxidans culture (cells and growth media) and their impact in bioflotation. Surface characteristics of chalcopyrite, sphalerite, and pyrrhotite, alone and in mixtures, after interaction with A. ferrooxidans were evaluated. Chalcopyrite floatability was increased substantially by biomodification, while bacteria depressed pyrrhotite floatability, favoring separation. The results showed that elemental sulfur concentration increased because of the oxidation generated by bacterial cells, the effect is intensified by the Fe(III) left in the culture and by galvanic contact. Acidithiobacillus ferrooxidans culture affects the Cu activation of sphalerite. The implications of elemental sulfur concentration and Cu activation of sphalerite are key factors that must be considered for the future development of sulfide bioflotation processes, since the depressive effect of cells could be counteracted by elemental sulfur generation.

  12. Bio-oxidation of galena particles by Acidithiobacillus ferrooxidans

    Institute of Scientific and Technical Information of China (English)

    Lei Jiang; Huaiyang Zhou; Xiaotong Peng; Zhonghao Ding

    2008-01-01

    This paper deals with the bio-oxidation of galena particles (-80 meshes) usingAcidithiobacillusferrooxidans and compares it with Fe3+ oxidation. Experimental results show that, at least, 0.00197 mol galena was leached from 100mL pulp (density of 3.8%) with 39 days' bio-oxidation, as compared to 0.00329 mol galena by Fe3+ with 9 days' oxidation. Because Fe3+ was constantly consumed, leaching by F3+e almost stopped after 9 days. Large amounts of lead sulfate were detected in both bio-oxidation and Fe3+ oxidation of galena. A. ferrooxidans followed a unique growth pattern during the bio-oxidation of galena. In the initial 15 days, the bacteria attached themselves to the galena surface with the formation of erosion pits similar in shape and length to those of the bacteria, and there were hardly any bacteria suspended in the solution. After 15 days, suspended bacteria increased. It is thus suggested that A. ferrooxidans may directly oxidize galena.

  13. Homology modeling and docking studies of IscS from extremophile Acidithiobacillus ferrooxidans

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The gene iscS-3 from Acidithiobacillus ferrooxidans may play a central role in the delivery of sulfur to a variety of metabolic pathways in this organism. For insight into the sulfur metabolic mechanism of the bacteria, an integral three-dimensional (3D) molecular structure of the protein encoded by this gene was built by homology modeling techniques, refined by molecular dynamics simulations, assessed by PROFILE-3D and PROSTAT programs and further used to search bind sites, carry out flexible docking with cofactor pyridoxal 5'-phosphate(PLP) and substrate cysteine and hereby detect its key residues. Through these procedures, the detail conformations of PLP-IscS(P-I) and cysteine-PLP-IscS(C-P-I) complexes were obtained. In P-I complex, the residues of Lys208, His106, Thr78, Ser205, His207, Asp182 and Gln185 have large interaction energies and/or hydrogen bonds fixation with PLP. In C-P-I complex, the amino group in cysteine is very near His106, Lys208 and PLP, the interaction energies for cysteine with them are very high. The above results are well consistent with those experimental facts of the homologues from other sources. Interestingly, the four residues of Glu105, Glu79, Ser203 and His180 in P-I docking and the residue of Lys213 in C-P-I docking also have great interaction energies, which are fitly conservation in IscSs from all kinds of sources but have not been identified before. From these results, this gene can be confirmed at 3D level to encode the iron-sulfur cluster assembly protein lscS and subsequently play a sulfur traffic role. Furthermore, the substrate cysteine can be presumed to be effectively recruited into the active site. Finally, the above detected key residues can be conjectured to be directly responsible for the bind and/or catalysis of PLP and cysteine.

  14. Bio-oxidation of pyrite, chalcopyrite and pyrrhotite by Acidithiobacillus ferrooxidans

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This paper deals with the bio-oxidation processes by Acidithiobacillus ferrooxidans of pyrite, chalcopyrite and pyrrhotite. Our experimental results show distinctive bio-oxidation characteristics for the three sulfide minerals. In the presence of A. ferrooxidans, the sulfide oxidation rates generally decrease in the order of pyrrhotite, chalcopyrite and pyrite. The pH during bio-oxidation of pyrite tends to decrease as a whole, whereas a rise-fall pattern was recorded for both chalcopyrite and pyrrhotite in their pH variations. No deposition was observed during the bio-oxidation of pyrite, suggesting a possible link to lower pH value in the process. However, large amounts of jarosite and element sulfur were determined in the bio-oxidation processes of chalcopyrite and pyrrhotite. A. ferrooxidans individuals were found directly as attachments to erosion pits on the smooth surface of pyrite. The erosion pits are similar to the bacterium in shape and length, and thus are probably products of dissolution of organic acid secreted by the cells on the mineral surface. More complicatedly, biofilm exists on the surfaces of chalcopyrite and pyrrhotite. This type of structured community of A. ferrooxidans is enclosed in the extracellular polymeric substances (EPS), and covered with the deposition generated in the bio-oxidation processes of chalcopyrite and pyrrhotite. Different bio-oxidation processes of pyrite, chalcopyrite and pyrrhotite may be linked mainly to characteristics of individual minerals and the pH in the reaction solution of the bio-oxidation system.

  15. Expression, purification and molecular modeling of iron-containing superoxide dismutase from Acidithiobacillus ferrooxidans

    Institute of Scientific and Technical Information of China (English)

    LIU Yuan-dong; GAO Jian; QIU Guan-zhou; LIU Xue-duan; ZHANG Cheng-gui; OUYANG Xu-dong; JIANG Ying; ZENG Jia

    2008-01-01

    The superoxide dismutase(SOD) from Acidithiobacillus ferrooxidans may play an important role in its tolerance to the extremely toxic and oxidative environment of bioleaching.This gene was cloned and then successfully expressed in Escherichia coli.The expressed protein was finally purified by one-step affinity chromatography to homogeneity and observed to be dimer according to SDS-PAGE and MALDI-TOF-MS.The metal content determination and optical spectra results of the recombinant protein confirmed that the protein was an iron-containing superoxide dismutase.Molecular modeling for the protein revealed that the iron atom was ligated by His26,His75,Asp158 and His162.

  16. Effect of pH values on the extracellular polysaccharide secreted by Acidithiobacillus ferrooxidans during chalcopyrite bioleaching

    Institute of Scientific and Technical Information of China (English)

    Run-lan Yu; Jing Liu; Jian-xi Tan; Wei-min Zeng; Li-juan Shi; Guo-hua Gu; Wen-qing Qin; Guan-zhou Qiu

    2014-01-01

    The pH value plays an important role in the bioleaching of sulphide minerals. The effect of pH values on the extracellular poly-saccharide secreted by Acidithiobacillus ferrooxidans was investigated in different phases of bacterial growth during chalcopyrite bioleach-ing. It is found that extracellular polysaccharide secretion from the cells attached to chalcopyrite is more efficiently than that of the free cells in the bioleaching solution. Three factors, pH values, the concentration of soluble metal ions, and the bacterial growth and metabolism, affect extracellular polysaccharide secretion in the free cells, and are related to the bacterial growth phase. Extracellular polysaccharide secretion from the attached cells is mainly dependent on the pH value of the bacterial culture.

  17. Mutagenic breeding of silver-resistant Acidithiobacillus ferrooxidans and exploration of resistant mechanism

    Institute of Scientific and Technical Information of China (English)

    WU Xue-ling; QIU Guan-zhou; GAO Jian; DING Jian-nan; KANG Jian; LIU Xin-xing

    2007-01-01

    The silver-resistant Acidithiobacillus ferrooxidans were isolated from 22 acid mine drainage (AMD) samples collected from Dexing Copper Mine and Chengmen Mountain Mine, Jiangxi Province, China. Isolate DX16 is obtained from the sample taken from Dexing Copper Mine and still carries out ferrous ion oxidation when incubated in 9K medium containing silver nitrate (240 mg/L). While isolate H1, a less resistant strain taken from Yin Mountain Mine, has a tolerate level of only 60 mg/L. Based on 16S ribosomal DNA sequencing, both bacterial 16SrDNA sequences are 100% similar to Acidithiobacillus ferrooxidans ATCC 23270. Through ultraviolet irradiation induced mutations, isolate mDX16 that is obtained from DX16 carries out ferrous ion oxidation when incubated in 9K medium containing higher concentration of silver nitrate (250 mg/L). When silver-resistant gene (SilC) analysis is carried out on the two isolates, it is seen that this gene was absent in both.

  18. Genes and pathways for CO2 fixation in the obligate, chemolithoautotrophic acidophile, Acidithiobacillus ferrooxidans, Carbon fixation in A. ferrooxidans

    Directory of Open Access Journals (Sweden)

    Esparza Mario

    2010-08-01

    Full Text Available Abstract Background Acidithiobacillus ferrooxidans is chemolithoautotrophic γ-proteobacterium that thrives at extremely low pH (pH 1-2. Although a substantial amount of information is available regarding CO2 uptake and fixation in a variety of facultative autotrophs, less is known about the processes in obligate autotrophs, especially those living in extremely acidic conditions, prompting the present study. Results Four gene clusters (termed cbb1-4 in the A. ferrooxidans genome are predicted to encode enzymes and structural proteins involved in carbon assimilation via the Calvin-Benson-Bassham (CBB cycle including form I of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO, EC 4.1.1.39 and the CO2-concentrating carboxysomes. RT-PCR experiments demonstrated that each gene cluster is a single transcriptional unit and thus is an operon. Operon cbb1 is divergently transcribed from a gene, cbbR, encoding the LysR-type transcriptional regulator CbbR that has been shown in many organisms to regulate the expression of RubisCO genes. Sigma70-like -10 and -35 promoter boxes and potential CbbR-binding sites (T-N11-A/TNA-N7TNA were predicted in the upstream regions of the four operons. Electrophoretic mobility shift assays (EMSAs confirmed that purified CbbR is able to bind to the upstream regions of the cbb1, cbb2 and cbb3 operons, demonstrating that the predicted CbbR-binding sites are functional in vitro. However, CbbR failed to bind the upstream region of the cbb4 operon that contains cbbP, encoding phosphoribulokinase (EC 2.7.1.19. Thus, other factors not present in the assay may be required for binding or the region lacks a functional CbbR-binding site. The cbb3 operon contains genes predicted to encode anthranilate synthase components I and II, catalyzing the formation of anthranilate and pyruvate from chorismate. This suggests a novel regulatory connection between CO2 fixation and tryptophan biosynthesis. The presence of a form II Rubis

  19. Inter- and intraspecific genomic variability of the 16S-23S intergenic spacer regions (ISR) in representatives of Acidithiobacillus thiooxidans and Acidithiobacillus ferrooxidans.

    Science.gov (United States)

    Ni, Yong-Qing; Yang, Yuan; Bao, Jing-Ting; He, Kai-Yu; Li, Hong-Yu

    2007-05-01

    The complete sequences of 32 intergenic spacer regions (ISR) from Acidithiobacillus strains, including 29 field strains isolated from coal, copper, molybdenum mine wastes or sediment of different geoclimatic regions in China, reference strain ATCC19859 and the type strains of the two species were determined. These data, together with other sequences available in the GenBank database, were used to carry out the first detailed assessment of the inter- and intraspecific genomic variability of the ISR sequences and to infer phylogenetic relationships within the genus. The total length of the 16S-23S rRNA intergenic spacer regions of the Acidithiobacillus thiooxidans and Acidithiobacillus ferrooxidans strains ranged from 451 to 490 bp, and from 434 to 456 bp, respectively. The degree of intrageneric ISR sequence similarity was higher than the degree of intergeneric similarity, and the overall similarity values of the ISRs varied from 60.49% to 84.71% between representatives of different species of the genus Acidithiobacillus. Sequences from the spacer of the A. thiooxidans and A. ferrooxidans strains ranged from 86.71% to 99.56% and 92.36% to 100% similarity, respectively. All Acidithiobacillus strains were separated into three phylogenetic major clusters and seven phylogenetic groups. ISR may be a potential target for the development of in situ hybridization probe aimed at accurately detecting acidithiobacilli in the various acidic environments.

  20. Bioinformatic Prediction of Gene Functions Regulated by Quorum Sensing in the Bioleaching Bacterium Acidithiobacillus ferrooxidans

    Directory of Open Access Journals (Sweden)

    Alvaro Banderas

    2013-08-01

    Full Text Available The biomining bacterium Acidithiobacillus ferrooxidans oxidizes sulfide ores and promotes metal solubilization. The efficiency of this process depends on the attachment of cells to surfaces, a process regulated by quorum sensing (QS cell-to-cell signalling in many Gram-negative bacteria. At. ferrooxidans has a functional QS system and the presence of AHLs enhances its attachment to pyrite. However, direct targets of the QS transcription factor AfeR remain unknown. In this study, a bioinformatic approach was used to infer possible AfeR direct targets based on the particular palindromic features of the AfeR binding site. A set of Hidden Markov Models designed to maintain palindromic regions and vary non-palindromic regions was used to screen for putative binding sites. By annotating the context of each predicted binding site (PBS, we classified them according to their positional coherence relative to other putative genomic structures such as start codons, RNA polymerase promoter elements and intergenic regions. We further used the Multiple EM for Motif Elicitation algorithm (MEME to further filter out low homology PBSs. In summary, 75 target-genes were identified, 34 of which have a higher confidence level. Among the identified genes, we found afeR itself, zwf, genes encoding glycosyltransferase activities, metallo-beta lactamases, and active transport-related proteins. Glycosyltransferases and Zwf (Glucose 6-phosphate-1-dehydrogenase might be directly involved in polysaccharide biosynthesis and attachment to minerals by At. ferrooxidans cells during the bioleaching process.

  1. Zinc bioleaching from an iron concentrate using Acidithiobacillus ferrooxidans strain from Hercules Mine of Coahuila, Mexico

    Science.gov (United States)

    Núñez-Ramírez, Diola Marina; Solís-Soto, Aquiles; López-Miranda, Javier; Pereyra-Alférez, Benito; Rutiaga-Quiñónes, Miriam; Medina-Torres, Luis; Medrano-Roldán, Hiram

    2011-10-01

    The iron concentrate from Hercules Mine of Coahuila, Mexico, which mainly contained pyrite and pyrrhotite, was treated by the bioleaching process using native strain Acidithiobacillus ferrooxidans ( A. ferrooxidans) to determine the ability of these bacteria on the leaching of zinc. The native bacteria were isolated from the iron concentrate of the mine. The bioleaching experiments were carried out in shake flasks to analyze the effects of pH values, pulp density, and the ferrous sulfate concentration on the bioleaching process. The results obtained by microbial kinetic analyses for the evaluation of some aspects of zinc leaching show that the native bacteria A. ferrooxidans, which is enriched with a 9K Silverman medium under the optimum conditions of pH 2.0, 20 g/L pulp density, and 40 g/L FeSO4, increases the zinc extraction considerably observed by monitoring during15 d, i.e., the zinc concentration has a decrease of about 95% in the iron concentrate.

  2. A Comparative Study on the Effect of Flotation Reagents on Growth and Iron Oxidation Activities of Leptospirillum ferrooxidans and Acidithiobacillus ferrooxidans

    Directory of Open Access Journals (Sweden)

    Mohammad Jafari

    2016-12-01

    Full Text Available Recently, extraction of metals from different resources using a simple, efficient, and low-cost technique-known as bioleaching-has been widely considered, and has turned out to be an important global technology. Leptospirillum ferrooxidans and Acidithiobacillus (Thiobacillus ferrooxidans are ubiquitous bacteria in the biomining industry. To date, the effects of commercial flotation reagents on the biooxidation activities of these bacteria have not been thoroughly studied. This investigation, by using various systematic measurement methods, studied the effects of various collectors and frothers (collectors: potassium amylxanthate, potassium isobutyl-xanthate, sodium ethylxanthate, potassium isopropylxanthate, and dithiophosphate; and frothers: pine oil and methyl isobutyl carbinol on L. ferrooxidans and A. ferrooxidans activities. In general, results indicate that in the presence of these collectors and frothers, L. ferrooxidans is less sensitive than T. ferrooxidans. In addition, the inhibition effect of collectors on both bacteria is recommended in the following order: for the collectors, potassium isobutyl-xanthate > dithiophosphate > sodium ethylxanthate > potassium isobutyl-xanthate > potassium amylxanthate; and for the frothers, methyl isobutyl carbinol > pine oil. These results can be used for the optimization of biometallurgical processes or in the early stage of a process design for selection of flotation reagents.

  3. Selective separation of arsenopyrite from pyrite by biomodulation in the presence of Acidithiobacillus ferrooxidans.

    Science.gov (United States)

    Chandraprabha, M N; Natarajan, K A; Somasundaran, P

    2004-08-15

    Effective methods for selective separation using flotation or flocculation of arsenopyrite from pyrite by biomodulation using Acidithiobacillus ferrooxidans are presented here. Adhesion of the bacterium to the surface of arsenopyrite was very slow compared to that to pyrite, resulting in a difference in surface modification of the minerals subsequent to interaction with cells. The cells were able to effectively depress pyrite flotation in presence of collectors like potassium isopropyl xanthate and potassium amyl xanthate. On the other hand the flotability of arsenopyrite after conditioning with the cells was not significantly affected. The activation of pyrite by copper sulfate was reduced when the minerals were conditioned together, resulting in better selectivity. Selective separation could also be achieved by flocculation of biomodulated samples.

  4. Bioleaching of zinc and iron from steel plant waste using Acidithiobacillus ferrooxidans.

    Science.gov (United States)

    Bayat, Oktay; Sever, Efsun; Bayat, Belgin; Arslan, Volkan; Poole, Colin

    2009-01-01

    The bacterial leaching of zinc and iron from solid wastes at the Isdemir iron and steel plant has been investigated using Acidithiobacillus ferrooxidans as the bacterial agent. The effects of a range of operational parameters, including particle size, solids concentration and pH, on the efficiency of the bioleaching process were investigated. In each test, several variables were determined to assess the efficiency of leaching, including slurry pH and redox potential, temperature, bacteria population and concentrations of zinc and iron in solution. Experimental results demonstrated that pulp solids concentration, slurry pH and solids particle size were all important parameters in the bacterial leaching process. Maximum extraction was achieved at pH values around 1.3 and a solids concentration of 1% w/v, with 35% of the Zn content and 37% of the Fe being dissolved.

  5. Study of Acidithiobacillus ferrooxidans and enzymatic bio-Fenton process-mediated corrosion of copper-nickel alloy.

    Science.gov (United States)

    Jadhav, U; Hocheng, H

    2016-10-01

    This study presents the corrosion behavior of the copper-nickel (Cu-Ni) alloy in the presence of Acidithiobacillus ferrooxidans (A. ferrooxidans) and glucose oxidase (GOx) enzyme. In both the cases ferric ions played an important role in weight loss and thereby to carry out the corrosion of the Cu-Ni alloy. A corrosion rate of 0.6 (±0.008), 2.11 (±0.05), 3.69 (±0.26), 0.7 (±0.006) and 0.08 (±0.002) mm/year was obtained in 72 h using 9K medium with ferrous sulfate, A. ferrooxidans culture supernatant, A. ferrooxidans cells, GOx enzyme and hydrogen peroxide (H2O2) solution respectively. The scanning electron microscopy (SEM) micrographs showed that a variable extent of corrosion was caused by 9K medium with ferrous sulfate, GOx and A. ferrooxidans cells. An arithmetic average surface roughness (Ra) of 174.78 nm was observed for the control work-piece using optical profilometer. The change in Ra was observed with the treatment of the Cu-Ni alloy using various systems. The Ra for 9K medium with ferrous sulfate, GOx and A. ferrooxidans cells was 374.54, 607.32 and 799.48 nm, respectively, after 24 h. These results suggest that A. ferrooxidans cells were responsible for more corrosion of the Cu-Ni alloy than other systems used.

  6. Cr and Ni recovery during bioleaching of dewatered metal-plating sludge using Acidithiobacillus ferrooxidans.

    Science.gov (United States)

    Rastegar, S O; Mousavi, S M; Shojaosadati, S A

    2014-09-01

    This study determined the optimal conditions required to attain maximum metal recovery in the bioleaching process of dewatered metal-plating sludge using Acidithiobacillus ferrooxidans (A. ferrooxidans). Adaptation of this strain was carried up to 1% (w/v) of the sample. Three factors including initial pH, initial Fe(3+) concentration and pulp density were selected as the effective factors and were optimized using a central composite design of response surface methodology. An initial pH of 1, pulp density of 9 g/l and initial Fe(3+) concentration of 1g/l were determined to be optimum values by the statistical models. The highest extractions for Cr and Ni under optimal conditions were 55.6% and 58.2%, respectively. Bioleaching kinetics was investigated using a modified shrinking core model to better understand the mechanism of the leaching reaction. The model predictions indicate that the diffusion step controlled the overall dissolution kinetics and is the rate controlling step.

  7. Immobilization of Acidithiobacillus ferrooxidans on Cotton Gauze for the Bioleaching of Waste Printed Circuit Boards.

    Science.gov (United States)

    Nie, Hongyan; Zhu, Nengwu; Cao, Yanlan; Xu, Zhiguo; Wu, Pingxiao

    2015-10-01

    The bioleaching parameters of metal concentrates from waste printed circuit boards by Acidithiobacillus ferrooxidans immobilized on cotton gauze in a two-step reactor were investigated in this study. The results indicated that an average ferrous iron oxidation rate of 0.54 g/(L·h) and a ferrous iron oxidation ratio of 96.90 % were obtained after 12 h at aeration rate of 1 L/min in bio-oxidation reactor. After 96 h, the highest leaching efficiency of copper reached 91.68 % under the conditions of the content of the metal powder 12 g/L, the retention time 6 h, and the aeration rate 1 L/min. The bioleaching efficiency of copper could be above 91.12 % under repeated continuous batch operation. Meanwhile, 95.32 % of zinc, 90.32 % of magnesium, 86.31 % of aluminum, and 59.07 % of nickel were extracted after 96 h. All the findings suggested that the recovery of metal concentrates from waste printed circuit boards via immobilization of A. ferrooxidans on cotton gauze was feasible.

  8. Column bioleaching copper and its kinetics of waste printed circuit boards (WPCBs) by Acidithiobacillus ferrooxidans.

    Science.gov (United States)

    Chen, Shu; Yang, Yuankun; Liu, Congqiang; Dong, Faqin; Liu, Bijun

    2015-12-01

    Application of bioleaching process for metal recovery from electronic waste has received an increasing attention in recent years. In this work, a column bioleaching of copper from waste printed circuit boards (WPCBs) by Acidithiobacillus ferrooxidans has been investigated. After column bioleaching for 28d, the copper recovery reached at 94.8% from the starting materials contained 24.8% copper. Additionally, the concentration of Fe(3+) concentration varied significantly during bioleaching, which inevitably will influence the Cu oxidation, thus bioleaching process. Thus the variation in Fe(3+) concentration should be taken into consideration in the conventional kinetic models of bioleaching process. Experimental results show that the rate of copper dissolution is controlled by external diffusion rather than internal one because of the iron hydrolysis and formation of jarosite precipitates at the surface of the material. The kinetics of column bioleaching WPCBs remains unchanged because the size and morphology of precipitates are unaffected by maintaining the pH of solution at 2.25 level. In bioleaching process, the formation of jarosite precipitate can be prevented by adding dilute sulfuric acid and maintaining an acidic condition of the leaching medium. In such way, the Fe(2)(+)-Fe(3+) cycle process can kept going and create a favorable condition for Cu bioleaching. Our experimental results show that column Cu bioleaching from WPCBs by A. ferrooxidans is promising.

  9. Optimization of magnetosome production by Acidithiobacillus ferrooxidans using desirability function approach

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Lei, E-mail: hekouyanlei@gmail.com [College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing 163319 (China); Zhang, Shuang [College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing 163319 (China); Liu, Hetao [School of Basic Medical Sciences, Ningxia Medical University, Yinchuan 750004 (China); Wang, Weidong [College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing 163319 (China); Chen, Peng; Li, Hongyu [School of Pharmacy, Lanzhou University, Lanzhou 730000 (China)

    2016-02-01

    Present study aimed to resolve the conflict between cell growth and magnetosome formation of Acidithiobacillus ferrooxidans (A. ferrooxidans) in batch experiments by applying response surface methodology (RSM) integrated a desirability function approach. The effects of several operating parameters on cell growth (OD{sub 600}) and magnetosome production (C{sub mag}) were evaluated. The maximum overall desirability (D) of 0.923 was achieved at iron concentration of 125.07 mM, shake speed of 122.37 rpm and nitrogen concentration of 2.40 g/L. Correspondingly, the OD{sub 600} and C{sub mag} were 0.522 and 1.196, respectively. The confirmation experiment confirmed that the optimum OD{sub 600} and C{sub mag} obtained were in good agreement with the predicted values. The inductively coupled plasma atomic emission spectrometer (ICP-AES) and transmission electron microscopy (TEM) analyses revealed that the production of magnetosomes could be improved via optimization. X-ray diffraction (XRD) showed the magnetosomes are magnetite. Results indicated that RSM with a desirability function was a useful technique to get the maximum OD{sub 600} and C{sub mag} simultaneously. - Highlights: • Optimization of magnetosome production by A. ferrooxidans using BBD of RSM. • Desirability function was used for concurrent maximization of cell and magnetosome yield. • ICP-AES results showed an increase in intracellular iron content through optimizing. • TEM showed a 2.5 fold increase in magnetosome number after optimization. • The methodology demonstrated a useful tool with an overall desirability of 0.923.

  10. A genomic island provides Acidithiobacillus ferrooxidans ATCC 53993 additional copper resistance: a possible competitive advantage.

    Science.gov (United States)

    Orellana, Luis H; Jerez, Carlos A

    2011-11-01

    There is great interest in understanding how extremophilic biomining bacteria adapt to exceptionally high copper concentrations in their environment. Acidithiobacillus ferrooxidans ATCC 53993 genome possesses the same copper resistance determinants as strain ATCC 23270. However, the former strain contains in its genome a 160-kb genomic island (GI), which is absent in ATCC 23270. This GI contains, amongst other genes, several genes coding for an additional putative copper ATPase and a Cus system. A. ferrooxidans ATCC 53993 showed a much higher resistance to CuSO(4) (>100 mM) than that of strain ATCC 23270 (<25 mM). When a similar number of bacteria from each strain were mixed and allowed to grow in the absence of copper, their respective final numbers remained approximately equal. However, in the presence of copper, there was a clear overgrowth of strain ATCC 53993 compared to ATCC 23270. This behavior is most likely explained by the presence of the additional copper-resistance genes in the GI of strain ATCC 53993. As determined by qRT-PCR, it was demonstrated that these genes are upregulated when A. ferrooxidans ATCC 53993 is grown in the presence of copper and were shown to be functional when expressed in copper-sensitive Escherichia coli mutants. Thus, the reason for resistance to copper of two strains of the same acidophilic microorganism could be determined by slight differences in their genomes, which may not only lead to changes in their capacities to adapt to their environment, but may also help to select the more fit microorganisms for industrial biomining operations. © Springer-Verlag 2011

  11. Molecular characterization ofAcidithiobacillus ferrooxidans strains isolated from different environments by three PCR-based methods

    Institute of Scientific and Technical Information of China (English)

    吴学玲; 刘莉莉; 张真真; 刘新星; 邓凡凡

    2015-01-01

    PCR-based DNA fingerprinting, REP-PCR (repetitive element PCR), RAPD (randomly amplified polymorphic DNA) and 16S rDNA sequence analyses were used to characterize 23Acidithiobacillus ferrooxidansstrains isolated from different environments. (GTG)5 and BOXA1R primer were selected for REP-PCR. Twenty arbitrary primers were used for RAPD to acquire DNA profiles fromA. ferrooxidans. Both RAPD and REP-PCR produce complex banding patterns and show good discriminatory ability in differentiating closely related strains ofA. ferrooxidans. The strains are clustered into 4 or 5 major groups and reveal genomic diversity using (GTG)5-PCR, BOX-PCR and RAPD analysis. Phylogenetic tree based on 16S rDNA sequences of 23 strains and related strains shows that they are clustered into two distinct groups. Twelve strains are highly related to a newAcidithiobacillus namedAcidithiobacillus ferrivorans. The results indicate that PCR-based methods are effective in revealing genetic diversity among A. ferrooxidans.

  12. The environmental context of Acidithiobacillus ferrooxidans and its potential role as an ecosystem engineer in sulphidic mine waste

    Energy Technology Data Exchange (ETDEWEB)

    Ebenaa, Gustav

    2001-06-01

    Microorganisms are the causative agent of the environmental problems since they catalyse the weathering of the (sulphidic) waste. The chemical oxidation alone is not fast enough to create any severe environmental problems. Acidithiobacillus ferrooxidans is thought to be a key organism in weathering of sulphide minerals. A. ferrooxidans is affected by several more or less abiotic factors. The influence of temperature, pH and nutrient deficiency as potentially limiting factors for the activity of A. ferrooxidans has been investigated. It seems that temperature has less influence on its activity, but rather reflects the origin of the bacterial isolate. An alkaline pH seems enough to hinder growth and activity. The nutrients do not seem to be a limiting factor in the studied environment. The possible regulation of the activity of A. ferrooxidans is therefore a way to, at least partly, mitigate the environmental impact from mine waste. Waste from the mining industry is the largest waste problem in Sweden. With amounts over 600 million tonnes one could easily imagine the tremendous cost involved in the abatement. The MiMi-programme, with researchers from several relevant fields, has as its aim to evaluate present and to find alternative techniques to mitigate the environmental impact from mine waste. The understanding of A. ferrooxidans and its role as an ecosystem engineer is essential both in evaluating present techniques and even more so in finding alternative abatement techniques for sulphidic mine waste.

  13. Ferrous iron oxidation by sulfur-oxidizing Acidithiobacillus ferrooxidans and analysis of the process at the levels of transcription and protein synthesis.

    Science.gov (United States)

    Kucera, Jiri; Bouchal, Pavel; Lochman, Jan; Potesil, David; Janiczek, Oldrich; Zdrahal, Zbynek; Mandl, Martin

    2013-04-01

    In contrast to iron-oxidizing Acidithiobacillus ferrooxidans, A. ferrooxidans from a stationary phase elemental sulfur-oxidizing culture exhibited a lag phase in pyrite oxidation, which is similar to its behaviour during ferrous iron oxidation. The ability of elemental sulfur-oxidizing A. ferrooxidans to immediately oxidize ferrous iron or pyrite without a lag phase was only observed in bacteria obtained from growing cultures with elemental sulfur. However, these cultures that shifted to ferrous iron oxidation showed a low rate of ferrous iron oxidation while no growth was observed. Two-dimensional gel electrophoresis was used for a quantitative proteomic analysis of the adaptation process when bacteria were switched from elemental sulfur to ferrous iron. A comparison of total cell lysates revealed 39 proteins whose increase or decrease in abundance was related to this phenotypic switching. However, only a few proteins were closely related to iron and sulfur metabolism. Reverse-transcription quantitative PCR was used to further characterize the bacterial adaptation process. The expression profiles of selected genes primarily involved in the ferrous iron oxidation indicated that phenotypic switching is a complex process that includes the activation of genes encoding a membrane protein, maturation proteins, electron transport proteins and their regulators.

  14. Bio-decomposition of rock phosphate containing pyrites by Acidithiobacillus ferrooxidans

    Institute of Scientific and Technical Information of China (English)

    CHI Ru-an; XIAO Chun-qiao; HUANG Xiao-hui; WANG Cun-wen; WU Yuan-xin

    2007-01-01

    Leaching soluble phosphorus from rock phosphate containing pyrites by Acidithiobacillus ferrooxidans (A. f) is feasible,and the reaction mechanism is as follows. Pyrites are oxidized by A. f. to produce H2SO4 and FeSO4; the rock phosphate is decomposed by H2SO4, forming soluble phosphorus compounds; and Fe2+ from FeSO4 is oxidized to Fe3+, providing energy for the growth of A. f.. In this process, as H2SO4 is produced in the reaction, an acidic condition in the culture medium is formed, which benefits the growth of A. f. and aids both continuous oxidation of pyrites and leaching of soluble phosphorus from rock phosphate.The fraction of phosphorous leached can reach the largest in the presence of 1.0 g/L Fe3+, 200 mg/L Mg2+ and 400 mg/L NH4+. The optimal technological parameters on the fraction of phosphorous leached are as follows: the volume fraction of inocula of A. f, the

  15. Full structure building and docking of NifS from extremophile Acidithiobacillus ferrooxidans

    Institute of Scientific and Technical Information of China (English)

    LIU Yuan-dong; QIU Guan-zhou; WANG Hai-dong; JIANG Ying; ZHANG Cheng-gui; XIA Le-xia

    2008-01-01

    The gene iscS-2 from extremophile Acidithiobacillus ferrooxidans may play a crucial role in nitrogenase maturation. To investigate the protein encoded by this gene, a reliable integral three-dimensional molecular structure was built. The obtained structure was further used to search binding sites, carry out the flexible docking with cofactor pyridoxal 5′-phosphate(PLP) and substrate cysteine, and identify its key residues. The docking results of PLP reveal that the residues of Lys203, His100, Thr73, Ser200, His202, Asp177 and Gln180 have large interaction energies and/or hydrogen bonds fixation with PLP. The docking results of cysteine show that the amino group in cysteine is very near His100, Lys203 and PLP, and the interaction energies for cysteine with them are very big. These identified residues are in line with the experimental facts of NifS from other sources. Moreover, the four residues of Asn152, Val179, Ala102 and Met148 in the PLP docking and the two residues of Lys208 and Ala102 in the cysteine docking also have large interaction energies, which are fitly conserved in NifS from all kinds of sources but have not been identified before. According to these results, this gene encodes NifS protein, and the substrate cysteine can be effectively recruited into the active site. Furthermore, all of the above detected key residues are directly responsible for the binding and/or catalysis of PLP and cysteine.

  16. Homology modeling and evolutionary trace analysis of superoxide dismutase from extremophile Acidithiobacillus ferrooxidans

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The gene sod in Acidithiobacillus ferrooxidans may play a crucial role in its tolerance to the extremely acidic, toxic and oxidative environment of bioleaching. For insight into the anti-toxic mechanism of the bacteria, a three-dimensional (3D) molecular structure of the protein encoded by this gene was built by homology modeling techniques, refined by molecular dynamics simulations, assessed by PROFILE-3D and PROSTAT programs and its key residues were further detected by evolutionary trace analysis. Through these procedures, some trace residues were identified and spatially clustered. Among them, the residues of Asn38, Gly103 and Glu161 are randomly scattered throughout the mapped structure; interestingly, the other residues are all distinctly clustered in a subgroup near Fe atom. From these results, this gene can be confirmed at 3D level to encode the Fe-depending superoxide dismutase and subsequently play an anti-toxic role. Furthermore, the detected key residues around Fe binding site can be conjectured to be directly responsible for Fe binding and catalytic function.

  17. Effect of Extracellular Polymeric Substances on Surface Properties and Attachment Behavior of Acidithiobacillus ferrooxidans

    Directory of Open Access Journals (Sweden)

    Qian Li

    2016-09-01

    Full Text Available Bacterial contact leaching of ores is more effective than non-contact leaching. Adhesion is the first step for leaching bacteria to form a biofilm on a mineral surface. Extracellular polymeric substances (EPS are pivotal for mediating bacterial adhesion to a substratum. In order to clarify the role of EPS, we measured the adhesion forces between chalcopyrite-, sulfur- or FeSO4·7H2O-grown cells of Acidithiobacillus ferrooxidans and chalcopyrite by an atomic force microscope (AFM before and after EPS removal. Surface properties of these cells were assessed by measurements of the contact angle, zeta potential, Fourier transform infrared spectroscopy (FTIR and acid-base titration. Bacterial attachment to chalcopyrite was monitored for 140 min. The results indicate that the EPS control the surface properties of the cells. In addition, the surface properties are decisive for adhesion. The adhesion forces and the amounts of attached cells decreased dramatically after removing EPS, which was not dependent on the preculture.

  18. Differentiation of Acidithiobacillus ferrooxidans and A. thiooxidans strains based on 16S-23S rDNA spacer polymorphism analysis.

    Science.gov (United States)

    Bergamo, Rogério F; Novo, Maria Teresa M; Veríssimo, Ricardo V; Paulino, Luciana C; Stoppe, Nancy C; Sato, Maria Inês Z; Manfio, Gilson P; Prado, Paulo Inácio; Garcia, Oswaldo; Ottoboni, Laura M M

    2004-09-01

    Restriction fragment length polymorphism (RFLP) and sequence analyses of the PCR-amplified 16S-23S rDNA intergenic spacer (ITS) were used for differentiating Acidithiobacillus thiooxidans strains from other related acidithiobacilli, including A. ferrooxidans and A. caldus. RFLP fingerprints obtained with AluI, DdeI, HaeIII, HinfI and MspI enabled the differentiation of all Acidithiobacillus reference strains into species groups. The A. thiooxidans strains investigated (metal mine isolates) yielded identical RFLP patterns to the A. thiooxidans type strain (ATCC 19377(T)), except for strain DAMS, which had a distinct pattern for all enzymes tested. Fourteen A. ferrooxidans mine strains were assigned to 3 RFLP groups, the majority of which were grouped with A. ferrooxidans ATCC 23270(T). The spacer region of one representative strain from each of the RFLP groups obtained was subjected to sequence analysis, in addition to eleven additional A. thiooxidans strains isolated from sediment and water samples, and A. caldus DSM 8584(T). The tRNA(IIe) and tRNA(Ala) genes, present in all strains analyzed, showed high sequence similarity. Phylogenetic analysis of the ITS sequences differentiated all three Acidithiobacillus species. Inter- and infraspecific genetic variations detected were mainly due to the size and sequence polymorphism of the ITS3 region. Mantel tests showed no significant correlation between ITS sequence similarity and the geographical origin of strains. The results showed that the 16S-23S rDNA spacer region is a useful target for the development of molecular-based methods aimed at the detection, rapid differentiation and identification of acidithiobacilli.

  19. A Tyrosine-Dependent Riboswitch Controls the Expression of a Tyrosyl-tRNA Synthetase from Acidithiobacillus ferrooxidans

    Directory of Open Access Journals (Sweden)

    Paula Bustamante

    2016-06-01

    Full Text Available Expression of aminoacyl-tRNA synthetases is regulated by a variety of mechanisms at the level of transcription or translation. A T-box dependent transcription termination / antitermination riboswitch system that responds to charged / uncharged tRNA regulates expression of aminoacyl tRNA synthetase genes in Gram-positive bacteria. TyrZ, the gene encoding tyrosyl-tRNA synthetase from Acidithiobacillus ferrooxidans, a Gram-negative acidophilic bacterium that participates in bioleaching of minerals, resembles the gene from Bacillus subtilis including the 5´-untranslated region encoding the riboswitch. Transcription of A. ferrooxidans tyrZ is induced by the presence of tyrosine by a mechanism involving antitermination of transcription. This mechanism is probably adapted to the low supply of amino acids of acidic environments of autotrophic bioleaching microorganisms. This work is licensed under a Creative Commons Attribution 4.0 International License.

  20. Synthesis of argentojarosite with simulated bioleaching solutions produced by Acidithiobacillus ferrooxidans

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, Chiranjit [Department of Microbiology, Ohio State University, 484 West 12" t" h Avenue, Columbus, OH 43210 (United States); Jones, F. Sandy; Bigham, Jerry M. [School of Environment and Natural Resources, Ohio State University, 2021 Coffey Road, Columbus, OH 43210 (United States); Tuovinen, Olli H., E-mail: tuovinen.1@osu.edu [Department of Microbiology, Ohio State University, 484 West 12" t" h Avenue, Columbus, OH 43210 (United States)

    2016-09-01

    Argentojarosite (AgFe{sub 3}(SO{sub 4}){sub 2}(OH){sub 6}) is formed as a secondary phase in Ag-catalyzed bioleaching of chalcopyrite (CuFeS{sub 2}), but to date very little is known about the paragenesis or characteristics of this silver-containing compound. The purpose of this study was to synthesize argentojarosite via biological oxidation of 120 mM ferrous sulfate by Acidithiobacillus ferrooxidans. Because of its toxicity to A. ferrooxidans, Ag{sup +} (as AgNO{sub 3}) was added to spent culture media (pH 2) after complete oxidation of ferrous sulfate. Schwertmannite (ideally Fe{sub 8}O{sub 8}(OH){sub 6}(SO{sub 4})) was precipitated during the iron oxidation phase, and subsequent Ag{sup +} addition resulted in the formation of argentojarosite. Contact time (8 h, 5 d, and 14 d) and Ag{sup +} concentration (0, 5, 20, and 40 mM) were used as variables in these experiments. Synthesis of argentojarosite, schwertmannite and other mineral phases was confirmed through X-ray diffraction analysis. Additional analyses of solid-phase oxidation products included elemental composition, color and specific surface area. The sample synthesized in the presence of 40 mM Ag{sup +} and with 14 d contact time yielded an X-ray diffraction pattern of well crystallized argentojarosite, and its elemental composition closely matched the calculated Ag, Fe, and S contents of ideal argentojarosite. The color and surface area of the remaining samples were influenced by the presence of residual schwertmannite. This phase remained stable over the time course of 14 d when no Ag{sup +} was present in the system. When equilibrations were extended to 42 d, partial conversion of reference schwertmannite to goethite was noted in the absence of Ag. In the presence of 20 mM or 40 mM Ag over the same time course, some formation of argentojarosite was also noted. In this case, schwertmannite was the only source of Fe and SO{sub 4} for argentojarosite formation. - Highlights: • Iron-oxidizing bacteria

  1. Reduction of arsenic content in a complex galena concentrate by Acidithiobacillus ferrooxidans

    Directory of Open Access Journals (Sweden)

    López Alejandro

    2004-10-01

    Full Text Available Abstract Background Bioleaching is a process that has been used in the past in mineral pretreatment of refractory sulfides, mainly in the gold, copper and uranium benefit. This technology has been proved to be cheaper, more efficient and environmentally friendly than roasting and high pressure moisture heating processes. So far the most studied microorganism in bioleaching is Acidithiobacillus ferrooxidans. There are a few studies about the benefit of metals of low value through bioleaching. From all of these, there are almost no studies dealing with complex minerals containing arsenopyrite (FeAsS. Reduction and/or elimination of arsenic in these ores increase their value and allows the exploitation of a vast variety of minerals that today are being underexploited. Results Arsenopyrite was totally oxidized. The sum of arsenic remaining in solution and removed by sampling represents from 22 to 33% in weight (yield of the original content in the mineral. The rest of the biooxidized arsenic form amorphous compounds that precipitate. Galena (PbS was totally oxidized too, anglesite (PbSO4 formed is virtually insoluble and remains in the solids. The influence of seven factors in a batch process was studied. The maximum rate of arsenic dissolution in the concentrate was found using the following levels of factors: small surface area of particle exposure, low pulp density, injecting air and adding 9 K medium to the system. It was also found that ferric chloride and carbon dioxide decreased the arsenic dissolution rate. Bioleaching kinetic data of arsenic solubilization were used to estimate the dilution rate for a continuous culture. Calculated dilution rates were relatively small (0.088–0.103 day-1. Conclusion Proper conditions of solubilization of arsenic during bioleaching are key features to improve the percentage (22 to 33% in weight of arsenic removal. Further studies are needed to determine other factors that influence specifically the

  2. Biooxidación de concentrados de arsenopirita por Acidithiobacillus ferrooxidans en erlenmeyer agitados

    Directory of Open Access Journals (Sweden)

    Juan David Ospina

    2012-03-01

    Full Text Available Normal 0 21 false false false ES-CO X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;} Título en ingles: Biooxidation of arsenopyrite concentrates by Acidithiobacillus ferrooxidans in shake flasks Resumen Se evaluó el proceso de biooxidación de concentrados de arsenopirita por A. ferrooxidans ATCC 23270, previa adaptación de los microorganismos al mineral y dos tamaños de partícula, pasante malla Tyler 200 (~75μm y 325 (~45μm. También, se determinó el grado de concentración del mineral mediante DRX y MOLPP/LR, bajo norma ASTM D 2799 de 2009. Los microorganismos fueron adaptados mediante disminución gradual, en etapas sucesivas, de sulfato ferroso y posterior aumento en el contenido de arsenopirita. Finalmente, se llevó a cabo el proceso de biooxidación del mineral sin adición de Fe2+. Después de treinta días de proceso, la disolución de arsénico para la malla Tyler 200 fue de 7550 mgL-1 (18,7% y para la malla Tyler 325 fue de 2850 mgL-1 (7,1%. Por otra parte, la curva de crecimiento bacteriano mostró que entre los días 6 y 21 de proceso la población bacteriana promedio fue de 1,70x108 cel.mL‐1 y de 8,00x107 cel.mL‐1 para las mallas Tyler 200 y 325, respectivamente. Por lo tanto, el tamaño de partícula jugó un papel fundamental en la cinética de adaptación de

  3. Sulphide bioxidation using native Acidithiobacillus ferrooxidans and thiooxidans, related acidophile strains from "El Zancudo" gold mine (Titiribí, Colombia

    Directory of Open Access Journals (Sweden)

    Diana M Ossa H

    2007-02-01

    Full Text Available This investigation was aimed at a laboratory evaluation of the action of native Acidithiobacillus ferrooxidans-and thiooxidans-related acidophile micro-organism (isolated from El Zancudo gold mine in Titiribí, Colombia on the oxidation of sulphides, mainly consisting of pyrite and arsenopyrite; sulphide concentration varied from 8% to 16% and particle size from 75 um to 106 um. pH and redox potential measurement revealed efficient oxidation for each culture over a 25-day period, reaching 1,4 pH and 600 mV redox potential. 20 g/L As and 60 g/L Fe levels were reached in solution. XRD, FTIR and SEM/EDX analysis revealed the presence of bacterial oxidation products such as jarosite and iron arsenates, as well as low and high corrosion in pyrites and arsenopyrites, respectively. Key words: chemolithotrophics, bioleaching, pyrite, arsenopyrite, applied mineralogy.

  4. Indução de Acidithiobacillus ferrooxidans e seleção de linhagens mutantes para utilização na biohidrometalurgia

    OpenAIRE

    Alves, Robson Caetano [UNESP

    2010-01-01

    A espécie bacteriana Acidithiobacillus ferrooxidans é o principal micro-organismo utilizado na biohidrometalurgia. Este processo permite a recuperação de metais de interesse econômico, que se encontram na natureza na forma de sulfetos minerais. O A. ferrooxidans obtém energia da oxidação de íons ferrosos e enxofre incluindo os sulfetos minerais, promovendo assim a solubilização dos metais. A calcopirita (CuFeS2) é um dos sulfetos de cobre mais abundante na natureza, porém, altamente refratári...

  5. Increases of ferrous iron oxidation activity and arsenic stressed cell growth by overexpression of Cyc2 in Acidithiobacillus ferrooxidans ATCC19859.

    Science.gov (United States)

    Liu, Wei; Lin, Jianqun; Pang, Xin; Mi, Shuang; Cui, Shuang; Lin, Jianqiang

    2013-01-01

    Acidithiobacillus ferrooxidans plays an important role in bioleaching in reproducing the mineral oxidant of ferric iron (Fe(3+) ) by oxidization of ferrous iron (Fe(2+) ). The high-molecular-weight c-type cytochrome Cyc2 that is located in the external membrane is postulated as the first electron carrier in the Fe(2+) oxidation respiratory pathway of A. ferrooxidans. To increase ferrous iron oxidation activity, a recombinant plasmid pTCYC2 containing cyc2 gene under the control of Ptac promoter was constructed and transferred into A. ferrooxidans ATCC19859. The transcriptional level of cyc2 gene was increased by 2.63-fold and Cyc2 protein expression was observed in the recombinant strain compared with the control. The ferrous iron oxidation activity and the arsenic stressed cell growth of the recombinant strain were also elevated.

  6. Attachment of Acidithiobacillus ferrooxidans and Leptospirillum ferriphilum cultured under varying conditions to pyrite, chalcopyrite, low-grade ore and quartz in a packed column reactor.

    Science.gov (United States)

    Africa, Cindy-Jade; van Hille, Robert P; Harrison, Susan T L

    2013-02-01

    The attachment of Acidithiobacillus ferrooxidans and Leptospirillum ferriphilum spp. grown on ferrous medium or adapted to a pyrite mineral concentrate to four mineral substrata, namely, chalcopyrite and pyrite concentrates, a low-grade chalcopyrite ore (0.5 wt%) and quartzite, was investigated. The quartzite represented a typical gangue mineral and served as a control. The attachment studies were carried out in a novel particle-coated column reactor. The saturated reactor containing glass beads, which were coated with fine mineral concentrates, provided a quantifiable surface area of mineral concentrate and maintained good fluid flow. A. ferrooxidans and Leptospirillum spp. had similar attachment characteristics. Enhanced attachment efficiency occurred with bacteria grown on sulphide minerals relative to those grown on ferrous sulphate in an ore-free environment. Selective attachment to sulphide minerals relative to gangue materials occurred, with mineral adapted cultures attaching to the minerals more efficiently than ferrous grown cultures. Mineral-adapted cultures showed highest levels of attachment to pyrite (74% and 79% attachment for A. ferrooxidans and L. ferriphilum, respectively). This was followed by attachment of mineral-adapted cultures to chalcopyrite (63% and 58% for A. ferrooxidans and L. ferriphilum, respectively). A. ferrooxidans and L. ferriphilum exhibited lower levels of attachment to low-grade ore and quartz relative to the sulphide minerals.

  7. Estudo da oxidação dos sulfetos sintéticos molibdenita (MoS2 e covelita (CuS por Acidithiobacillus ferrooxidans via respirometria celular Oxidation study of the synthetic sulfides molybdenite (MoS2 and covellite (CuS by Acidithiobacillus ferrooxidans using respirometric experiments

    Directory of Open Access Journals (Sweden)

    Wilmo E. Francisco Junior

    2009-01-01

    Full Text Available This paper analyses the oxidation of covellite and molybdenite by Acidithiobacillus ferrooxidans strain LR using respirometric experiments. The results showed that both sulfides were oxidized by A. ferrooxidans, however, the covellite oxidation was much higher than molybdenite. Regarding the kinetic oxidation, the findings revealed that just molybdenite oxidation followed the classical Michaelis-Menten kinetic. It is probably associated with the pathway which these sulfides react to chemistry-bacterial attack, what is influenced by its electronic structures. Besides, experiments conducted in the presence of Fe3+ did not indicate alterations in molybdenite oxidation. Thus, ferric ions seem not to be essential to the sulfide oxidations.

  8. Microbial recovery of copper from printed circuit boards of waste computer by Acidithiobacillus ferrooxidans.

    Science.gov (United States)

    Choi, Moon-Sung; Cho, Kyung-Suk; Kim, Dong-Su; Kim, Dong-Jin

    2004-01-01

    The bioleaching of copper contained in the printed circuit boards (PCB) of waste computers by A. ferrooxidans was studied. The Fe oxidation rates by A. ferrooxidans in the 9K medium supplemented with the leachate of PCB (0.15-0.13 g L(-1) d(-1)) were similar to that in the 9K medium without the leachate (0.15 g L(-1) d(-1)). This finding suggests that the leachate of PCB did not seriously affect the bioleaching process by this bacterium. The amount of copper leached from PCB shreds increased with the addition of ferrous ion and reached up to 5190 mg L(-1) when the initial concentration of Fe2+ ion was 7 g L(-1). As the microbial leaching progressed, pale brown precipitate was observed to form in the solution. Based on the total amount of copper, both in solution and precipitate, the optimal addition of ferrous ion for the leaching of copper was around 7 g L(-1). When citric acid was not added, only about 37 wt% of the total leached copper remained dissolved; however, the amount of dissolved copper increased to greater than 80 wt% in the presence of citric acid. This fact indicates that the addition of a complexing agent (citric acid) to the bioleaching solution can raise the solubility of the leached metal ions.

  9. Synchrotron radiation based STXM analysis and micro-XRF mapping of differential expression of extracellular thiol groups by Acidithiobacillus ferrooxidans grown on Fe(2+) and S(0).

    Science.gov (United States)

    Xia, Jin-Lan; Liu, Hong-Chang; Nie, Zhen-Yuan; Peng, An-An; Zhen, Xiang-Jun; Yang, Yun; Zhang, Xiu-Li

    2013-09-01

    The differential expression of extracellular thiol groups by Acidithiobacillus ferrooxidans grown on substrates Fe(2+) and S(0) was investigated by using synchrotron radiation based scanning transmission X-ray microscopy (STXM) imaging and microbeam X-ray fluorescence (μ-XRF) mapping. The extracellular thiol groups (SH) were first alkylated by iodoacetic acid forming Protein-SCH2COOH and then the P-SCH2COOH was marked by calcium ions forming P-SCH2COOCa. The STXM imaging and μ-XRF mapping of SH were based on analysis of SCH2COO-bonded Ca(2+). The results indicated that the thiol group content of A. ferrooxidans grown on S(0) is 3.88 times to that on Fe(2+). Combined with selective labeling of SH by Ca(2+), the STXM imaging and μ-XRF mapping provided an in situ and rapid analysis of differential expression of extracellular thiol groups.

  10. Evaluación de oxidación bacteriana de sulfuros con Acidithiobacillus ferrooxidans mediante pruebas de FTIR y difracción de rayos X Evaluating Acidithiobacillus ferrooxidans bacterial oxidation of sulphur compounds using FTIR and X-ray diffraction assays

    Directory of Open Access Journals (Sweden)

    Ruiz Orlando

    2003-06-01

    Full Text Available Una cepa bacteriana nativa con capacidad de oxidar hierro ferroso y compuestos del azufre fue aislada a partir de efluentes y material de la mina de oro La Maruja, en el municipio de Marmato (Caldas, la cual fue identificada bioquímicamente como Acidithiobacillus ferrooxidans. Esta cepa fue evaluada en su capacidad de oxidar concentra­dos de sulfuros metálicos a dos diferentes concentraciones de pulpa y dos tamaños de partícula. Después de 15 días de biooxidación de los sulfuros se observó que, efectivamente, la bacteria mostró acción catalizadora sobre el proce­so de disolución del mineral. Palabras clave: biooxidación; biolixiviación; A. ferrooxidans; sulfuros metálicosA native bacterial strain capable of oxidising ferrous iron and sulphur compounds was isolated from effluent and material from the La Maruja gold mine in the municipality of Marmato (Caldas; this was biochemically identified as being Acidithiobacillus ferrooxidans. This strain's ability to oxidise metallic sulphide concentrates having two differ-ent pulp proportions and two particle sizes was evaluated. Sulphide bio-oxidation was observed after 15 days showing this strain's catalytic action on the mineral break-down process. Key words: bio-oxidation; bio-leaching; A. ferrooxidans; sulphides

  11. Oxidation of dibenzothiophene as a model substrate for the removal of organic sulphur from fossil fuels by iron(III ions generated from pyrite by Acidithiobacillus ferrooxidans

    Directory of Open Access Journals (Sweden)

    VLADIMIR P. BESKOSKI

    2007-06-01

    Full Text Available Within this paper a new idea for the removal of organically bonded sulphur from fossil fuels is discussed. Dibenzothiophene (DBT was used as a model compound of organicmolecules containing sulphur. This form of (biodesulphurization was performed by an indirect mechanism in which iron(III ions generated from pyrite by Acidithiobacillus ferrooxidans performed the abiotic oxidation. The obtained reaction products, dibenzothiopene sulfoxide and dibenzothiophene sulfone, are more soluble in water than the basic substrate and the obtained results confirmed the basic hypothesis and give the posibility of continuing the experiments related to application of this (biodesulphurization process.

  12. Quantitative X-ray photoelectron spectroscopy-based depth profiling of bioleached arsenopyrite surface by Acidithiobacillus ferrooxidans

    Science.gov (United States)

    Zhu, Tingting; Lu, Xiancai; Liu, Huan; Li, Juan; Zhu, Xiangyu; Lu, Jianjun; Wang, Rucheng

    2014-02-01

    In supergene environments, microbial activities significantly enhance sulfide oxidation and result in the release of heavy metals, causing serious contamination of soils and waters. As the most commonly encountered arsenic mineral in nature, arsenopyrite (FeAsS) accounts for arsenic contaminants in various environments. In order to investigate the geochemical behavior of arsenic during microbial oxidation of arsenopyrite, (2 3 0) surfaces of arsenopyrite slices were characterized after acidic (pH 2.00) and oxidative decomposition with or without an acidophilic microorganism Acidithiobacillus ferrooxidans. The morphology as well as chemical and elemental depth profiles of the oxidized arsenopyrite surface were investigated by scanning electron microscopy and X-ray photoelectron spectroscopy. With the mediation of bacteria, cell-shaped and acicular pits were observed on the reacted arsenopyrite surface, and the concentration of released arsenic species in solution was 50 times as high as that of the abiotic reaction after 10 days reaction. Fine-scale XPS depth profiles of the reacted arsenopyrite surfaces after both microbial and abiotic oxidation provided insights into the changes in chemical states of the elements in arsenopyrite surface layers. Within the 450 nm surface layer of abiotically oxidized arsenopyrite, Fe(III)-oxides appeared and gradually increased towards the surface, and detectable sulfite and monovalent arsenic appeared above 50 nm. In comparison, higher contents of ferric sulfate, sulfite, and arsenite were found in the surface layer of approximately 3 μm of the microbially oxidized arsenopyrite. Intermediates, such as Fe(III)-AsS and S0, were detectable in the presence of bacteria. Changes of oxidative species derived from XPS depth profiles show the oxidation sequence is Fe > As = S in abiotic oxidation, and Fe > S > As in microbial oxidation. Based on these results, a possible reaction path of microbial oxidation was proposed in a concept model.

  13. Insights into the Quorum Sensing Regulon of the Acidophilic Acidithiobacillus ferrooxidans Revealed by Transcriptomic in the Presence of an Acyl Homoserine Lactone Superagonist Analog.

    Science.gov (United States)

    Mamani, Sigde; Moinier, Danielle; Denis, Yann; Soulère, Laurent; Queneau, Yves; Talla, Emmanuel; Bonnefoy, Violaine; Guiliani, Nicolas

    2016-01-01

    While a functional quorum sensing system has been identified in the acidophilic chemolithoautotrophic Acidithiobacillus ferrooxidans ATCC 23270(T) and shown to modulate cell adhesion to solid substrates, nothing is known about the genes it regulates. To address the question of how quorum sensing controls biofilm formation in A. ferrooxidans (T), the transcriptome of this organism in conditions in which quorum sensing response is stimulated by a synthetic superagonist AHL (N-acyl homoserine lactones) analog has been studied. First, the effect on biofilm formation of a synthetic AHL tetrazolic analog, tetrazole 9c, known for its agonistic QS activity, was assessed by fluorescence and electron microscopy. A fast adherence of A. ferrooxidans (T) cells on sulfur coupons was observed. Then, tetrazole 9c was used in DNA microarray experiments that allowed the identification of genes regulated by quorum sensing signaling, and more particularly, those involved in early biofilm formation. Interestingly, afeI gene, encoding the AHL synthase, but not the A. ferrooxidans quorum sensing transcriptional regulator AfeR encoding gene, was shown to be regulated by quorum sensing. Data indicated that quorum sensing network represents at least 4.5% (141 genes) of the ATCC 23270(T) genome of which 42.5% (60 genes) are related to biofilm formation. Finally, AfeR was shown to bind specifically to the regulatory region of the afeI gene at the level of the palindromic sequence predicted to be the AfeR binding site. Our results give new insights on the response of A. ferrooxidans to quorum sensing and on biofilm biogenesis.

  14. A new iron-oxidizing/O2-reducing supercomplex spanning both inner and outer membranes, isolated from the extreme acidophile Acidithiobacillus ferrooxidans.

    Science.gov (United States)

    Castelle, Cindy; Guiral, Marianne; Malarte, Guillaume; Ledgham, Fouzia; Leroy, Gisèle; Brugna, Myriam; Giudici-Orticoni, Marie-Thérèse

    2008-09-19

    The iron respiratory chain of the acidophilic bacterium Acidithiobacillus ferrooxidans involves various metalloenzymes. Here we demonstrate that the oxygen reduction pathway from ferrous iron (named downhill pathway) is organized as a supercomplex constituted of proteins located in the outer and inner membranes as well as in the periplasm. For the first time, the outer membrane-bound cytochrome c Cyc2 was purified, and we showed that it is responsible for iron oxidation and determined that its redox potential is the highest measured to date for a cytochrome c. The organization of metalloproteins inside the supramolecular structure was specified by protein-protein interaction experiments. The isolated complex spanning the two membranes had iron oxidase as well as oxygen reductase activities, indicating functional electron transfer between the first iron electron acceptor, Cyc2, and the Cu(A) center of cytochrome c oxidase aa(3). This is the first characterization of a respirasome from an acidophilic bacterium. In Acidithiobacillus ferrooxidans,O(2) reduction from ferrous iron must be coupled to the energy-consuming reduction of NAD(+)(P) from ferrous iron (uphill pathway) required for CO(2) fixation and other anabolic processes. Besides the proteins involved in the O(2) reduction, there were additional proteins in the supercomplex, involved in uphill pathway (bc complex and cytochrome Cyc(42)), suggesting a possible physical link between these two pathways.

  15. Comparación del potencial oxidativo de Acidithiobacillus ferrooxidans, en un proceso de biodesulfurización de carbón

    Directory of Open Access Journals (Sweden)

    Maria Prada Fonseca

    2016-05-01

    Full Text Available This study aimed comparing the oxidative activity of two strains of Acidithiobacillus ferrooxidans in a desulphurization process, using a sub-bituminous coal with a high sulfur content (2.30% total sulfur: 1.06% as pyritic, 1.10% as organic and 0.14% from sulfates from “La Guacamaya” mine, located in Puerto Libertador - Cordoba, Colombia. Several assays were performed in Erlenmeyer flasks, the total iron concentration used in solution were 200 mg/L and 1200 mg/L respectively, using ferrous sulfate. The process was monitored by periodically measuring the main physicochemical factors involved (pH, Eh, cell population and iron in solution. According to the results obtained, the highest efficiency of the process was achieved by working with microorganisms compatible with Acidithiobacillus ferrooxidans and initial concentration of 1200 mg/l of ferrous sulfate, which had higher pyrite oxidation rates (Py oxidized up to 68% and the best experimental conditions in the leaching medium (pH: 1,47; Eh: 625 mV; 6.3×108 cells/mL, in comparison with the axenic culture on the same conditions (Py oxidized: 52%; pH: 1,63; Eh: 580 mV; 5.1×108cells/mL, after 12 days of experimentation.

  16. Addition of citrate to Acidithiobacillus ferrooxidans cultures enables precipitate-free growth at elevated pH and reduces ferric inhibition.

    Science.gov (United States)

    Li, Xiaozheng; Mercado, Roel; Kernan, Timothy; West, Alan C; Banta, Scott

    2014-10-01

    Acidithiobacillus ferrooxidans is an acidophilic chemolithoautotroph that is important in biomining and other biotechnological operations. The cells are able to oxidize inorganic iron, but the insolubility and product inhibition by Fe(3+) complicates characterization of these cultures. Here we explore the growth kinetics of A. ferrooxidans in iron-based medium in a pH range from 1.6 to 2.2. It was found that as the pH was increased from 1.6 to 2.0, the maintenance coefficient decreased while both the growth kinetics and maximum cell yield increased in the precipitate-free, low Fe(2+) concentration medium. In higher iron media a similar trend was observed at low pH, but the formation of precipitates at higher pH (2.0) hampered cell growth and lowered the specific growth rate and maximum cell yield. In order to eliminate ferric precipitates, chelating agents were introduced into the medium. Citric acid was found to be relatively non-toxic and did not appear to interfere with iron oxidation at a maximum concentration of 70 mM. Inclusion of citric acid prevented precipitation and A. ferrooxidans growth parameters resumed their trends as a function of pH. The addition of citrate also decreased the apparent substrate saturation constant (KS ) indicating a reduction in the competitive inhibition of growth by ferric ions. These results indicate that continuous cultures of A. ferrooxidans in the presence of citrate at elevated pH will enable enhanced cell yields and productivities. This will be critical as these cells are used in the development of new biotechnological applications such as electrofuel production.

  17. Interaction of Acidithiobacillus ferrooxidans, Rhizobium phaseoli and Rhodotorula sp. in bioleaching process based on Lotka–Volterra model

    Directory of Open Access Journals (Sweden)

    Xuecheng Zheng

    2016-07-01

    Conclusion: The relationship among microorganisms during leaching could be described appropriately by Lotka–Volterra model between the initial and peak values. The relationship of A. ferrooxidans and R. phaseoli could be considered as mutualism, whereas, the relationship of A. ferrooxidans and R. phaseoli could be considered as commensalism.

  18. Expression and activity of the Calvin-Benson-Bassham cycle transcriptional regulator CbbR from Acidithiobacillus ferrooxidans in Ralstonia eutropha.

    Science.gov (United States)

    Esparza, Mario; Jedlicki, Eugenia; Dopson, Mark; Holmes, David S

    2015-08-01

    Autotrophic fixation of carbon dioxide into cellular carbon occurs via several pathways but quantitatively, the Calvin-Benson-Bassham cycle is the most important. CbbR regulates the expression of the cbb genes involved in CO2 fixation via the Calvin-Benson-Bassham cycle in a number of autotrophic bacteria. A gene potentially encoding CbbR (cbbR(AF)) has been predicted in the genome of the chemolithoautotrophic, extreme acidophile Acidithiobacillus ferrooxidans. However, this microorganism is recalcitrant to genetic manipulation impeding the experimental validation of bioinformatic predictions. Two novel functional assays were devised to advance our understanding of cbbR(AF) function using the mutated facultative autotroph Ralstonia eutropha H14 ΔcbbR as a surrogate host to test gene function: (i) cbbR(AF) was expressed in R. eutropha and was able to complement ΔcbbR; and (ii) CbbR(AF) was able to regulate the in vivo activity of four A. ferrooxidans cbb operon promoters in R. eutropha. These results open up the use of R. eutropha as a surrogate host to explore cbbR(AF) activity.

  19. Differential expression of two bc1 complexes in the strict acidophilic chemolithoautotrophic bacterium Acidithiobacillus ferrooxidans suggests a model for their respective roles in iron or sulfur oxidation.

    Science.gov (United States)

    Bruscella, Patrice; Appia-Ayme, Corinne; Levicán, Gloria; Ratouchniak, Jeanine; Jedlicki, Eugenia; Holmes, David S; Bonnefoy, Violaine

    2007-01-01

    Three strains of the strict acidophilic chemolithoautotrophic Acidithiobacillus ferrooxidans, including the type strain ATCC 23270, contain a petIIABC gene cluster that encodes the three proteins, cytochrome c1, cytochrome b and a Rieske protein, that constitute a bc1 electron-transfer complex. RT-PCR and Northern blotting show that the petIIABC cluster is co-transcribed with cycA, encoding a cytochrome c belonging to the c4 family, sdrA, encoding a putative short-chain dehydrogenase, and hip, encoding a high potential iron-sulfur protein, suggesting that the six genes constitute an operon, termed the petII operon. Previous results indicated that A. ferrooxidans contains a second pet operon, termed the petI operon, which contains a gene cluster that is similarly organized except that it lacks hip. Real-time PCR and Northern blot experiments demonstrate that petI is transcribed mainly in cells grown in medium containing iron, whereas petII is transcribed in cells grown in media containing sulfur or iron. Primer extension experiments revealed possible transcription initiation sites for the petI and petII operons. A model is presented in which petI is proposed to encode the bc1 complex, functioning in the uphill flow of electrons from iron to NAD(P), whereas petII is suggested to be involved in electron transfer from sulfur (or formate) to oxygen (or ferric iron). A. ferrooxidans is the only organism, to date, to exhibit two functional bc1 complexes.

  20. Oxidation study of the synthetic sulfides molybdenite (MoS{sub 2}) and covellite (CuS) by acidithiobacillus ferrooxidants using respirometric experiments; Estudo da oxidacao dos sulfetos sinteticos molibdenita (MoS2) e covelita (CuS) por Acidithiobacillus ferrooxidans via respirometria celular

    Energy Technology Data Exchange (ETDEWEB)

    Francisco Junior, Wilmo E. [Universidade Federal de Rondonia (UFRO), Porto Velho, RO (Brazil). Dept. de Quimica; Universidade Estadual Paulista (UNESP), Araraquara, SP (Brazil). Inst. de Quimica. Dept. de Bioquimica e Tecnologia Quimica], e-mail: wilmojr@bol.com.br; Bevilaqua, Denise; Garcia Junior, Oswaldo [Universidade Estadual Paulista (UNESP), Araraquara, SP (Brazil). Inst. de Quimica. Dept. de Bioquimica e Tecnologia Quimica

    2009-07-01

    This paper analyses the oxidation of covellite and molybdenite by Acidithiobacillus ferrooxidans strain LR using respirometric experiments. The results showed that both sulfides were oxidized by A. ferrooxidans, however, the covellite oxidation was much higher than molybdenite. Regarding the kinetic oxidation, the findings revealed that just molybdenite oxidation followed the classical Michaelis-Menten kinetic. It is probably associated with the pathway which these sulfides react to chemistry-bacterial attack, what is influenced by its electronic structures. Besides, experiments conducted in the presence of Fe{sup 3+} did not indicate alterations in molybdenite oxidation. Thus, ferric ions seem not to be essential to the sulfide oxidations. (author)

  1. The Cultivation of Acidithiobacillus Ferrooxidans and the Investigation of Influencing Factors%嗜酸氧化亚铁硫杆菌培养及其影响因素∗

    Institute of Scientific and Technical Information of China (English)

    邓蓉; 张小云; 张梦雪; 廖美霞; 曾子宁

    2014-01-01

    研究了温度、pH 值、溶氧量(以转速表征)、金属离子浓度等因素对氧化亚铁硫杆菌的生长状况及体内 ATP 酶活力的影响,确定了最适的培养条件.通过对比培养前与培养后微生物扫描电镜(SEM),探讨环境胁迫对微生物表面形貌和菌体生长的影响.结果表明,初始 pH 2.0,温度30℃,转速150 r/min,氧化亚铁硫杆菌培养60 h,酶的活性较高,其中最大值为2.8 U/mL,金属离子 Zn2+、Cu2+、Mg2+会降低微生物 ATP酶的活性,当 Zn2+浓度小于0.03 mol/L,Cu2+浓度小于0.08 mol/L,Mg2+浓度小于0.04 mol/L时,对微生物的抑制作用不明显.初始 pH=2.0,温度30℃,转速150 r/min,培养嗜酸氧化亚铁硫杆菌,与对照菌株相比,菌体形状大小没有明显变化,菌体数量显著增加,菌体表面有生物膜形成.%The effect of some factors on the growth and ATP-ase activity of Acidithiobacillus ferrooxi-dans,such as solution temperature,pH,dissolved oxygen and the concentration of metal ions is studied. The influence of environmental condition on microbial surface and the growth of Acidithiobacillus ferrooxi-dans is investigated by the scanning electron microscope(SEM)of per-cultivated and post-cultivated Acidi-thiobacillus ferrooxidans .The results show that under the condition of initial pH 2.0,temperature 30 ℃, speed 150 r/min,cultivated time 60 h,the ATP-ase activity becomes higher,and the largest ATP-ase activ-ity is 2.8 U/mL,Zn2+,Cu2+ and Mg2+ can reduce ATP-ase activity,however,when the concentration of Zn2+,Cu2+ and Mg2+ is less than 0.03,0.08 and 0.04 mol/L respectively,the inhibitory effect is not obvi-ous.The scanning electron microscope(SEM)of per-cultivated and post-cultivated Acidithiobacillus ferro-oxidans show that the number of Acidithiobacillus ferrooxidans increase remarkably,biofilms grew in the surface of Acidithiobacillus ferrooxidans,appreciable change is not found in the shape size of Acidithiobacil-lus ferrooxidans.

  2. Development of Fluorenscent Quantitative Real-time PCR Method for Detection of Acidithiobacillus ferrooxidans%嗜酸氧化亚铁硫杆菌实时荧光定量PCR检测方法的建立

    Institute of Scientific and Technical Information of China (English)

    唐连飞; 肖家勇; 朱中武; 孟芳; 欧阳振宇; 陈盼; 白雪; 禹思宇

    2010-01-01

    [目的] 建立一种检测进出境环保用微生物菌剂中嗜酸氧化亚铁硫杆菌(acidithiobacillus ferrooxidans,A.ferrooxidans)的实时荧光定量PCR方法.[方法] 用9K培养基培养 A.ferrooxidans标准菌株A.ferrooxidans ATCC23270,并提取基因组DNA作模板;根据GenBank中嗜酸氧化亚铁硫杆菌的16S基因序列设计合成引物和探针,用含有101 bp扩增目标产物的pGEM()-T Easy载体质粒为阳性对照.构建标准曲线,建立荧光定量PCR检测方法,并进行方法 学的评估.[结果] 成功建立了嗜酸氧化亚铁硫杆菌的荧光定量PCR检测方法,该方法对嗜酸硫杆菌属中嗜酸氧化硫硫杆菌(Acidithiobacillus thiooxidans,A.thiooxidans)和嗜酸喜温硫杆菌(Acidithiobacillus caldus,A.caldus)无交叉反应;最少可检测到100个阳性质粒,说明有很好的敏感性;试验内变异系数为0.32%,具有很好的重复性.[结论] 建立的嗜酸氧化亚铁硫杆菌的TaqMan探针荧光定量PCR检测方法特异性和灵敏度高、重复性好,可作为嗜酸氧化亚铁硫杆菌高通量的快速检测方法.

  3. The Study Kinetic for Growth of Acidithiobacillus ferrooxidans%嗜酸氧化亚铁硫杆菌生长动力学

    Institute of Scientific and Technical Information of China (English)

    柳建设; 张艳华; 李邦梅; 谢学辉

    2006-01-01

    在确定二价铁离子为A.f生长过程中惟一限制性底物条件下,通过考察初始亚铁离子浓度、初始pH值两种影响亚铁离子氧化代谢的主要因素来研究细菌的生长特性,得到以限制性底物亚铁离子浓度为表征的细菌生长曲线.利用基于Monod方程建立的细菌生长动力学方程模型,采用Matlab软件中的Gauiss-Newton算法确定了在不同条件下细菌生长动力学参数,包括最大比生长速率μm、Monod常数K及Ro,推导出了不同条件下A.f对数期以底物Fe(Ⅱ)浓度为表征的生长动力学方程.%In order to explain kinetic behaviors of microorganisms in varied experiment conditions, growth kinetic model of Acidithiobacillus ferrooxidans (A. f) was deduced based on Monod model. The kinetic parameters (Monod constant K, max specific growth rate μm, and Ro) of this model in different initial experiment condition were obtained by Gauss-Newton algorithm. The growth law in specific initial experiment condition and variable kinetic parameters were found. According to the growth behavior law studied under different initial experiment condition, the curves describing substrates (ferrous ion concentration) law and the growth velocity equations corresponding to the different initial experiment condition were obtained.

  4. Sulfur metabolism in the extreme acidophile Acidithiobacillus caldus

    Directory of Open Access Journals (Sweden)

    Stefanie eMangold

    2011-02-01

    Full Text Available Given the challenges to life at low pH, an analysis of inorganic sulfur compound oxidation was initiated in the chemolithoautotrophic extremophile Acidithiobacillus caldus. A. caldus is able to metabolize elemental sulfur and a broad range of inorganic sulfur compounds. It has been implicated in the production of environmentally damaging acidic solutions as well as participating in industrial bioleaching operations where it forms part of microbial consortia used for the recovery of metal ions. Based upon the recently published A. caldus type strain genome sequence, a bioinformatic reconstruction of elemental sulfur and inorganic sulfur compound metabolism predicted genes included: sulfide quinone reductase (sqr, tetrathionate hydrolase (tth, two sox gene clusters potentially involved in thiosulfate oxidation (soxABXYZ, sulfur oxygenase reductase (sor, and various electron transport components. RNA transcript profiles by semi-quantitative reverse transcription PCR suggested up-regulation of sox genes in the presence of tetrathionate. Extensive gel based proteomic comparisons of total soluble and membrane enriched protein fractions during growth on elemental sulfur and tetrathionate identified differential protein levels from the two Sox clusters as well as several chaperone and stress proteins up-regulated in the presence of elemental sulfur. Proteomics results also suggested the involvement of heterodisulfide reductase (HdrABC in A. caldus inorganic sulfur compound metabolism. A putative new function of Hdr in acidophiles is discussed. Additional proteomic analysis evaluated protein expression differences between cells grown attached to solid, elemental sulfur versus planktonic cells. This study has provided insights into sulfur metabolism of this acidophilic chemolithotroph and gene expression during attachment to solid elemental sulfur.

  5. Synthesis and properties of ternary (K, NH{sub 4}, H{sub 3}O)-jarosites precipitated from Acidithiobacillus ferrooxidans cultures in simulated bioleaching solutions

    Energy Technology Data Exchange (ETDEWEB)

    Sandy Jones, F.; Bigham, Jerry M. [School of Environment and Natural Resources, Ohio State University, 2021 Coffey Road, Columbus, OH 43210 (United States); Gramp, Jonathan P. [Department of Microbiology, Ohio State University, 484 West 12th Avenue, Columbus, OH 43210 (United States); Tuovinen, Olli H., E-mail: tuovinen.1@osu.edu [Department of Microbiology, Ohio State University, 484 West 12th Avenue, Columbus, OH 43210 (United States)

    2014-11-01

    The purpose of this study was to synthesize a series of solid solution jarosites by biological oxidation of ferrous iron at pH 2.2–4.4 and ambient temperature in media containing mixtures of K{sup +} (0, 1, 4, 6, 12, 31 mM) and NH{sub 4}{sup +} (6.1, 80, 160, 320 mM). The starting material was a liquid medium for Acidithiobacillus ferrooxidans comprised of 120 mM FeSO{sub 4} solution and mineral salts at pH 2.2. Following inoculation with A. ferrooxidans, the cultures were incubated in shake flasks at 22 °C. As bacteria oxidized ferrous iron, ferric iron hydrolyzed and precipitated as jarosite-group minerals (AFe{sub 3}(SO{sub 4}){sub 2}(OH){sub 6}) and/or schwertmannite (idealized formula Fe{sub 8}O{sub 8}(OH){sub 6}(SO{sub 4})·nH{sub 2}O). The precipitates were characterized by X-ray diffraction (XRD), elemental analysis, and Munsell color. Schwertmannite was the dominant mineral product at low combinations of K{sup +} (≤ 4 mM) and NH{sub 4}{sup +} (≤ 80 mM) in the media. At higher single or combined concentrations, yellowish jarosite phases were produced, and Munsell hue provided a sensitive means of detecting minor schwertmannite in the oxidation products. Although the hydrated ionic radii of K{sup +} and NH{sub 4}{sup +} are similar, K{sup +} greatly facilitated the formation of a jarosite phase compared to NH{sub 4}{sup +}. Unit cell and cell volume calculations from refinements of the powder XRD patterns indicated that the jarosite phases produced were mostly ternary (K, NH{sub 4}, H{sub 3}O)-solid solutions that were also deficient in structural Fe, especially at low NH{sub 4} contents. Thus, ferric iron precipitation from the simulated bioleaching systems yielded solid solutions of jarosite with chemical compositions that were dependent on the relative concentrations of K{sup +} and NH{sub 4}{sup +} in the synthesis media. No phase separations involving discrete, end-member K-jarosite or NH{sub 4}-jarosite were detected in the un-aged precipitates

  6. Effect of calcium oxide on the efficiency of ferrous ion oxidation and total iron precipitation during ferrous ion oxidation in simulated acid mine drainage treatment with inoculation of Acidithiobacillus ferrooxidans.

    Science.gov (United States)

    Liu, Fenwu; Zhou, Jun; Jin, Tongjun; Zhang, Shasha; Liu, Lanlan

    2016-01-01

    Calcium oxide was added into ferrous ion oxidation system in the presence of Acidithiobacillus ferrooxidans at concentrations of 0-4.00 g/L. The pH, ferrous ion oxidation efficiency, total iron precipitation efficiency, and phase of the solid minerals harvested from different treatments were investigated during the ferrous ion oxidation process. In control check (CK) system, pH of the solution decreased from 2.81 to 2.25 when ferrous ions achieved complete oxidation after 72 h of Acidithiobacillus ferrooxidans incubation without the addition of calcium oxide, and total iron precipitation efficiency reached 20.2%. Efficiency of ferrous ion oxidation and total iron precipitation was significantly improved when the amount of calcium oxide added was ≤1.33 g/L, and the minerals harvested from systems were mainly a mixture of jarosite and schwertmannite. For example, the ferrous ion oxidation efficiency reached 100% at 60 h and total iron precipitation efficiency was increased to 32.1% at 72 h when 1.33 g/L of calcium oxide was added. However, ferrous ion oxidation and total iron precipitation for jarosite and schwertmannite formation were inhibited if the amount of calcium oxide added was above 2.67 g/L, and large amounts of calcium sulfate dihydrate were generated in systems.

  7. The Global Redox Responding RegB/RegA Signal Transduction System Regulates the Genes Involved in Ferrous Iron and Inorganic Sulfur Compound Oxidation of the Acidophilic Acidithiobacillus ferrooxidans

    Directory of Open Access Journals (Sweden)

    Danielle Moinier

    2017-07-01

    Full Text Available The chemical attack of ore by ferric iron and/or sulfuric acid releases valuable metals. The products of these reactions are recycled by iron and sulfur oxidizing microorganisms. These acidophilic chemolithotrophic prokaryotes, among which Acidithiobacillus ferrooxidans, grow at the expense of the energy released from the oxidation of ferrous iron and/or inorganic sulfur compounds (ISCs. In At. ferrooxidans, it has been shown that the expression of the genes encoding the proteins involved in these respiratory pathways is dependent on the electron donor and that the genes involved in iron oxidation are expressed before those responsible for ISCs oxidation when both iron and sulfur are present. Since the redox potential increases during iron oxidation but remains stable during sulfur oxidation, we have put forward the hypothesis that the global redox responding two components system RegB/RegA is involved in this regulation. To understand the mechanism of this system and its role in the regulation of the aerobic respiratory pathways in At. ferrooxidans, the binding of different forms of RegA (DNA binding domain, wild-type, unphosphorylated and phosphorylated-like forms of RegA on the regulatory region of different genes/operons involved in ferrous iron and ISC oxidation has been analyzed. We have shown that the four RegA forms are able to bind specifically the upstream region of these genes. Interestingly, the phosphorylation of RegA did not change its affinity for its cognate DNA. The transcriptional start site of these genes/operons has been determined. In most cases, the RegA binding site(s was (were located upstream from the −35 (or −24 box suggesting that RegA does not interfere with the RNA polymerase binding. Based on the results presented in this report, the role of the RegB/RegA system in the regulation of the ferrous iron and ISC oxidation pathways in At. ferrooxidans is discussed.

  8. The Global Redox Responding RegB/RegA Signal Transduction System Regulates the Genes Involved in Ferrous Iron and Inorganic Sulfur Compound Oxidation of the Acidophilic Acidithiobacillus ferrooxidans.

    Science.gov (United States)

    Moinier, Danielle; Byrne, Deborah; Amouric, Agnès; Bonnefoy, Violaine

    2017-01-01

    The chemical attack of ore by ferric iron and/or sulfuric acid releases valuable metals. The products of these reactions are recycled by iron and sulfur oxidizing microorganisms. These acidophilic chemolithotrophic prokaryotes, among which Acidithiobacillus ferrooxidans, grow at the expense of the energy released from the oxidation of ferrous iron and/or inorganic sulfur compounds (ISCs). In At. ferrooxidans, it has been shown that the expression of the genes encoding the proteins involved in these respiratory pathways is dependent on the electron donor and that the genes involved in iron oxidation are expressed before those responsible for ISCs oxidation when both iron and sulfur are present. Since the redox potential increases during iron oxidation but remains stable during sulfur oxidation, we have put forward the hypothesis that the global redox responding two components system RegB/RegA is involved in this regulation. To understand the mechanism of this system and its role in the regulation of the aerobic respiratory pathways in At. ferrooxidans, the binding of different forms of RegA (DNA binding domain, wild-type, unphosphorylated and phosphorylated-like forms of RegA) on the regulatory region of different genes/operons involved in ferrous iron and ISC oxidation has been analyzed. We have shown that the four RegA forms are able to bind specifically the upstream region of these genes. Interestingly, the phosphorylation of RegA did not change its affinity for its cognate DNA. The transcriptional start site of these genes/operons has been determined. In most cases, the RegA binding site(s) was (were) located upstream from the -35 (or -24) box suggesting that RegA does not interfere with the RNA polymerase binding. Based on the results presented in this report, the role of the RegB/RegA system in the regulation of the ferrous iron and ISC oxidation pathways in At. ferrooxidans is discussed.

  9. 嗜酸氧化亚铁硫杆菌的分离鉴定及对废胎面胶的脱硫再生%Isolation and identification of Acidithiobacillus ferrooxidans and its desulfurization reclamation of ground tyre rubber

    Institute of Scientific and Technical Information of China (English)

    王雅琴; 俞汪洋; 赵素合; 李元虎; 姜广明

    2011-01-01

    从河北兴隆某硫铁矿筛选到一株硫杆菌YT-1,经理化性能和16S rDNA序列分析鉴定为嗜酸氧化亚铁硫杆菌(At.ferrooxidans YT-1),研究了该菌对废胎面胶(GTR)的脱硫再生作用.研究结果表明,三元共混物丁苯橡胶(SBR)/炭黑(CB)/再生GTR比SBR/CB/未再生GTR拉伸强度和断裂伸长率分别提高了5.3%和11.1%;X射线光电能谱检测表明SBR/CB/再生GTR表面硫元素质量分数降低13.92%,且峰位往高氧化态偏移0.2 eV,说明再生GTR表面硫元素被氧化;共混胶断裂面扫描电子显微镜显示再生GTR与SBR/CB基体粘合性能显著提高,说明再生GTR表面硫交联键被打断.%A strain of Thiobacillus YT-1 has been isolated from iron pyrites from Xinglong in Hebei province, and was identified as Acidithiobacillus ferrooxidans (At. ferrooxidans YT-1 ) by its physicochemical properties and 16S rDNA gene sequence analysis. Microbial desulfurization of ground tyre rubber (GTR) was carried out by At. ferrooxidans YT-1. Samples of reclaimed GTR and untreated GTR were blended with a styrene-butadiene rubber/carbon black (SBR/CB) matrix. The tensile strength and elongation at break of SBR/CB/reclaimed GTR were respectively 5.3、 and 11.1% higher than the corresponding values for the SBR/CB/untreated GTR blend. X-ray photoelectron spectroscopy (XPS) indicated that the surface sulfur content of SBR/CB/reclaimed GTR was reduced 13.92%. In addition, the S peak shifted about by 0. 2 eV to high binding energy, which indicates that the surface sulfur bridges of the reclaimed GTR have been oxidized. Scanning electron microscopy (SEM) images of the fracture surface morphology showed better adhesion between SBR/CB and reclaimed GTR, which confirms that the surface of the reclaimed GTR was modified by At. ferrooxidans YT-1 and became more compatible with the SBR.

  10. Study on Leaching of Cobalt White Alloy by Acidithiobacillus ferrooxidans%氧化亚铁硫杆菌浸出钴白合金

    Institute of Scientific and Technical Information of China (English)

    胡国宏; 肖利; 方正; 钟晖

    2012-01-01

    用氧化亚铁硫杆菌(A.f菌)浸出难破碎的钴白合金,研究结果表明,A.f菌最适生长pH值为2.0,最佳生长温度为30℃.对9K培养基培养的A.f菌进行了3种处理方式实验:(1)直接接种:合金中钴浸出完成需6d,铜8 d;(2)从菌液中离心收集:合金中钴浸出完成需3d,铜需7 d;(3)经适应性培养:钴浸出完成需2d,铜需5d.浸出过程中pH值先增大后逐渐降低,电极电位随铜的浸出面增大.经适应性培养的A.f菌浸出白合金,浸渣成分为极少量的黄氨铁矾,钴和铜的浸出率分别达99.5%和99.0%.A.f菌浸出钴白合金中铜的作用机理为间接作用.%Acidithiobacillus ferrooxidans (A.f) was used for leaching of the hard cobalt white alloy. The experiments determined the optimum pH value and temperature in the presence of A.f to be 2.0 and 30℃, respectively. Three modes of treatment of the bacteria, which are directly inoculated with 107 cells/mL in 9K culture medium, dispersed to 107 cells/mL in iron-free 9K culture medium and beforehand adapted by the alloy and collected by centrifugation, were used. The result showed that for the first mode, it took 6 d to finish the leaching of cobalt and 8 d for copper with decrease in number of the bacteria in leaching. For the second one, it needed 3 and 7 d to dissolve cobalt and copper out, respectively, and accompanied decrease in the bacteria. And for the third one, the modified A.f could be increased to 108 cells/mL, and the leaching of two metals was for 2 d and 5 d, respectively. In the leaching process, pH value increased first and then decreased. The electric potential increased with the leaching of copper. With the bacteria which were beforehand adapted by the leaching of cobalt white alloy, its leaching residue contained a little ammonium jarosite and the leaching rates of cobalt and copper were 99.50% and 99.0%. The leaching mechanism of copper in cobalt white alloy by A.f was the indirect effect.

  11. Harmless research of printed circuit board sludge byAcidithiobacillus ferrooxidans%嗜酸氧化亚铁硫杆菌处理线路板行业污泥的无害化

    Institute of Scientific and Technical Information of China (English)

    李东明; 白建峰; 张承龙; 戴珏; 苑文仪; 邓明强; 毛文雄; 王景伟

    2015-01-01

    The sludge from printed circuit board (PCB) industry was treated harmlessly by the bioleaching method. In the experiment,Acidithiobacillus ferrooxidans (hereafter abbreviated asA.f), which was selected from the copper mine, was used in the bioleaching process. For the original state of the strain, the effect of leaching time, pH value, acclimation period, solid-to-liquid ratio, concentration of ferrous sulfate on bioleaching valuable metals from the sludge were investigated. The results showed that high concentrations of heavy metals in the solution would inhibit the leaching rate of metals by the strain when the solid-to-liquid ratio exceeded 1:20. But the tolerance of the strain could enhance through the continuous acclimation. With a five cycles of continuous domestication for the strain in the bioleaching solution, the ability of the strain leaching metals from the sludge was improved significantly. Leaching rates of Cu, Ni and Zn from the sludge could reach 78%, 53% and 74% respectively under the optical conditions, which were FeSO4•7H20concentration of 60g/L, pH value of 0.5, extraction time of 6days, ratio of solid-to-liquid of 1:10in 9K medium. So the environmentally friendly method would provide support for the PCB industry.%研究了一株用于浸出线路板中Cu的嗜酸性氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans简称:A.f菌)在高固液比下无害化处理线路板污泥的影响.实验以A.f菌为原始菌种,通过周期性的驯化培养,在不同的浸出条件下探究了生物浸出时间、培养基pH值、菌种驯化周期、固液比和硫酸亚铁浓度等因素对A.f菌浸出线路板行业污泥中有价金属的影响.结果表明:当固液比高于1:20时,溶液中高浓度的重金属对微生物浸出有抑制作用,但通过连续的驯化培养可以提高菌种的耐受性,在FeSO4·7H2O投加量为60g/L、9k培养基初始pH为0.5、浸出时间为6d、固液比为1:10的条件下, Cu

  12. Microbial leaching of marmatite by Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans

    Institute of Scientific and Technical Information of China (English)

    WANG Jun; QIU Guan-zhou; QIN Wen-qing; ZHANG Yan-sheng

    2006-01-01

    The bioleaching of marmatite in shaken flasks was studied. After leaching for 29 days, the leaching ratio of zinc was 91%.Three kinds of bacteria, mixture-based bacteria, 9K-based bacteria and sulfur-based bacteria were used in marmatite leaching, of which the mixture-based bacteria have the best leaching result while the sulfur-based bacteria have the worst. By analyzing the leaching residue using SEM and EDXA, the marmatite leaching mechanism was discussed.

  13. 嗜酸性氧化亚铁硫杆菌休止细胞保存时间及循环利用对施氏矿物生物合成的影响%Effects of storage time and recycling of resting Acidithiobacillus ferrooxidans cells on biogenic schwertmannite formation

    Institute of Scientific and Technical Information of China (English)

    柏双友; 梁剑茹; 廖岳华; 周立祥

    2011-01-01

    利用嗜酸性氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans,简称A.ferrooxidans)休止细胞促进FeSO4形成的施氏矿物具有纯度高比表面积大的特点,对去除水环境中有毒重(类)金属有重要作用.为提供施氏矿物规模化生产优化参数,本研究通过摇瓶试验探讨了休止细胞保存时间对其活力的影响,以及休止细胞再次循环利用对施氏矿物生物合成中Fe2+氧化率和矿物产量的影响.结果表明,新鲜制备的A.ferrooxidans菌休止细胞可在48 h内将144 mmol·L-1 Fe2+(250 mL体系)全部氧化成Fe3+,在高浓度SO24-存在下约有41.99%的Fe3+被转化成棕红色施氏矿物沉淀,矿物产量达到1.34 g.当休止细胞在4℃保存达45 d时,Fe2+氧化率与新鲜细胞相比下降5.61%,施氏矿物产量降低35.07%.二次利用的循环A.ferrooxidans菌氧化Fe2+的能力大幅下降,其氧化性能只占新鲜休止细胞的1/7,这主要是由菌体本身氧化活性下降和矿物吸附包裹部分A.ferrooxidans菌导致菌体数量下降两个原因所致.可见,新制备的A.ferrooxidans菌休止细胞应现制现用,在4℃、pH=2.5的酸水中保存时间不宜超过30 d,A.ferrooxidans菌休止细胞可循环利用于施氏矿物的生物合成,但其效能仅为新鲜休止细胞的15%左右.%Schwertmannite biosynthesized by resting Acidithiobacillus ferrooxidans (A. ferrooxidans) with FeSO4 has high purity and specific surface area. It can play an important role in the removal of toxic heavy metals or metalloids in water environments. To provide the optimum parameters for industrial scale production of schwertmannite, the effects of storage time of resting A. ferrooxidans cells and reuse of the recycling cells on the strain growth andits ability to facilitate Fe2 + oxidation and mineral formation were investigated in batch experiments. The results indicated that the fresh resting A.ferrooxidans cells harvested within 30 d could completely oxidize 144 mmol·L- 1 Fe2

  14. Improved chalcopyrite bioleaching by Acidithiobacillus sp. via direct step-wise regulation of microbial community structure.

    Science.gov (United States)

    Feng, Shoushuai; Yang, Hailin; Wang, Wu

    2015-09-01

    A direct step-wise regulation strategy of microbial community structure was developed for improving chalcopyrite bioleaching by Acidithiobacillus sp. Specially, the initial microbial proportion between Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans was controlled at 3:1 with additional 2 g/L Fe(2+) for faster initiating iron metabolism. A. thiooxidans biomass was fed via a step-wise strategy (8-12th d) with the microbial proportion 1:1 for balancing community structure and promoting sulfur metabolism in the stationary phase. A. thiooxidans proportion was further improved via another step-wise feeding strategy (14-18th d) with the microbial proportion 1:2 for enhancing sulfur metabolism and weakening jarosite passivation in the later phase. With the community structure-shift control strategy, biochemical reaction was directly regulated for creating a better balance in different phases. Moreover, the final copper ion was increased from 57.1 to 93.2 mg/L, with the productivity 2.33 mg/(Ld). The novel strategy may be valuable in optimization of similar bioleaching process.

  15. 黄钾铁矾的生成机理及其对嗜酸氧化亚铁硫杆菌有重要作用的离子的影响%Formation of jarosite and its effect on important ions for Acidithiobacillus ferrooxidans bacteria

    Institute of Scientific and Technical Information of China (English)

    B.NAZARI; E.JORJANI; H.HANI; Z.MANAFI; A.RIAHI

    2014-01-01

    黄钾铁矾的生成对Sarcheshmeh生物堆浸硫化铜矿有不利影响。实验研究了在嗜酸氧化亚铁硫杆菌存在的情况下,生长介质中Fe(II)的初始浓度、pH及温度影响黄钾铁矾沉淀形成的机理。产生最多Fe(III)沉淀的条件为:硫酸亚铁浓度50 g/L、初始pH 2.2、温度32°C。 Fe(III)沉淀的生成影响了对嗜酸氧化亚铁硫杆菌有重要作用的离子的浓度,比如:Fe3+、2-4SO 、K+、3-4PO 、Mg2+。对于Fe3+和K+,他们有相似的模式,这些离子共沉淀而形成黄钾铁矾的组分。在pH高于1.6时,由于3-4PO 与黄钾铁矾共沉淀以及嗜酸氧化亚铁硫杆菌较快的生长速度而导致合3-4PO 的化合物的溶解度急剧降低。在生物堆浸的初期,由于脉石的溶解,Mg2+浓度增大,随后缓慢降低。%The precipitation of jarosite adversely affects the bio-leaching of copper sulfides in the Sarcheshmeh heap bio-leaching process. The variables of the initial concentration of ferrous iron in the growth medium, pH, and temperature were examined in the laboratory to determine how they affect the precipitation of jarosite in the presence of Acidithiobacillus ferrooxidans bacteria. It was found that the maximum ferric precipitate occurred at a ferrous sulfate concentration of 50 g/L, a temperature of 32 °C, and an initial pH value of 2.2. The effects of the precipitation of ferric iron on the quantities of ions that are important for A. ferrooxidans bacteria in aqueous phase, i.e., ferric, sulfate, potassium, phosphate, and magnesium ions, also were assessed. The results showed relatively similar patterns for the ferric and potassium ions, and then reason might have been the co-precipitation of these ions as constituent elements of jarosite mineral. At pH values greater than 1.6, the solubility of phosphate ions decreased dramatically due to the co-precipitation of phosphate ions with the jarosite precipitate and due to the significant growth rate of

  16. The effect of the introduction of exogenous strain Acidithiobacillus thiooxidans A01 on functional gene expression, structure and function of indigenous consortium during pyrite bioleaching.

    Science.gov (United States)

    Liu, Yi; Yin, Huaqun; Zeng, Weimin; Liang, Yili; Liu, Yao; Baba, Ngom; Qiu, Guanzhou; Shen, Li; Fu, Xian; Liu, Xueduan

    2011-09-01

    Acidithiobacillus thiooxidans A01 was added to a consortium of bioleaching bacteria including Acidithiobacilluscaldus, Leptospirillumferriphilum, Acidithiobacillus ferrooxidans, Sulfobacillus thermosulfidooxidans, Acidiphilium spp., and Ferroplasma thermophilum cultured in modified 9 K medium containing 0.5% (w/v) pyrite, and 10.7% increase of bioleaching rate was observed. Changes in community structure and gene expression were monitored with real-time PCR and functional gene arrays (FGAs). Real-time PCR showed that addition of At. thiooxidans caused increased numbers of all consortium members except At. caldus, and At. caldus, L. ferriphilum, and F. thermophilum remained dominant in this community. FGAs results showed that after addition of At. thiooxidans, most genes involved in iron, sulfur, carbon, and nitrogen metabolisms, metal resistance, electron transport, and extracellular polymeric substances of L. ferriphilum, F. thermophilum, and Acidiphilium spp., were up-regulated while most of these genes were down-regulated at 70-78 h in At. caldus and up-regulated in At. ferrooxidans, then down-regulated at 82-86 h.

  17. Geochemical diversity in S processes mediated by culture-adapted and environmental-enrichments of Acidithiobacillus spp.

    Science.gov (United States)

    Bernier, Luc; Warren, Lesley A.

    2007-12-01

    Coupled S speciation and acid generation resulting from S processing associated with five different microbial treatments, all primarily Acidithiobacillus spp. (i.e. autotrophic S-oxidizers) were evaluated in batch laboratory experiments. Microbial treatments included two culture-adapted strains, Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans, their consortia and two environmental enrichments from a mine tailings lake that were determined to be >95% Acidithiobacillus spp., by whole-cell fluorescent hybridization. Using batch experiments simulating acidic mine waters with no carbon amendments, acid generation, and S speciation associated with the oxidation of three S substrates (thiosulfate, tetrathionate, and elemental S) were evaluated. Aseptic controls showed no observable pH decrease over the experimental time course (1 month) for all three S compounds examined. In contrast, pH decreased in all microbial treatments from starting pH values of 4 to 2 or less for all three S substrates. Results show a non-linear relationship between the pH dynamics of the batch cultures and their corresponding sulfate concentrations, and indicate how known microbial S processing pathways have opposite impacts, ultimately on pH dynamics. Associated geochemical modeling indicated negligible abiogenic processes contributing to the observed results, indicating strong microbial control of acid generation extending over pH ranges from 4 to less than 2. However, the observed acid generation rates and associated S speciation were both microbial treatment and substrate-specific. Results reveal a number of novel insights regarding microbial catalysis of S oxidation: (1) metabolic diversity in S processing, as evidenced by the observed geochemical signatures in S chemical speciation and rates of acid generation amongst phylogenetically similar organisms (to the genus level); (2) consortial impacts differ from those of individual strain members; (3) environmental enrichments

  18. Community dynamics of attached and free cells and the effects of attached cells on chalcopyrite bioleaching by Acidithiobacillus sp.

    Science.gov (United States)

    Yang, Hailin; Feng, Shoushuai; Xin, Yu; Wang, Wu

    2014-02-01

    The community dynamics of attached and free cells of Acidithiobacillus sp. were investigated and compared during chalcopyrite bioleaching process. In the mixed strains system, Acidithiobacillus ferrooxidans was the dominant species at the early stage while Acidithiobacillus thiooxidans owned competitive advantage from the middle stage to the end of bioprocess. Meanwhile, compared to A. ferrooxidans, more significant effects of attached cells on free biomass with A. thiooxidans were shown in either the pure or mixed strains systems. Moreover, the effects of attached cells on key chemical parameters were also studied in different adsorption-deficient systems. Consistently, the greatest reduction of key chemical ion was shown with A. thiooxidans and the loss of bioleaching efficiency was high to 50.5%. These results all demonstrated the bioleaching function of attached cells was more efficient than the free cells, especially with A. thiooxidans. These notable results would help us to further understand the chalcopyrite bioleaching.

  19. Recovery of Nickel and Cobalt from Laterite Tailings by Reductive Dissolution under Aerobic Conditions Using Acidithiobacillus Species.

    Science.gov (United States)

    Marrero, J; Coto, O; Goldmann, S; Graupner, T; Schippers, A

    2015-06-01

    Biomining of sulfidic ores has been applied for almost five decades. However, the bioprocessing of oxide ores such as laterites lags commercially behind. Recently, the Ferredox process was proposed to treat limonitic laterite ores by means of anaerobic reductive dissolution (AnRD), which was found to be more effective than aerobic bioleaching by fungi and other bacteria. We show here that the ferric iron reduction mediated by Acidithiobacillus thiooxidans can be applied to an aerobic reductive dissolution (AeRD) of nickel laterite tailings. AeRD using a consortium of Acidithiobacillus thiooxidans and Acidithiobacillus ferrooxidans extracted similar amounts of nickel (53-57%) and cobalt (55-60%) in only 7 days as AnRD using Acidithiobacillus ferrooxidans. The economic and environmental advantages of AeRD for processing of laterite tailings comprise no requirement for an anoxic atmosphere, 1.8-fold less acid consumption than for AnRD, as well as nickel and cobalt recovered in a ferrous-based pregnant leach solution (PLS), facilitating the subsequent metal recovery. In addition, an aerobic acid regeneration stage is proposed. Therefore, AeRD process development can be considered as environmentally friendly for treating laterites with low operational costs and as an attractive alternative to AnRD.

  20. Growth kinetics of Thiobacillus ferrooxidans in bioelectrochemical cell

    Institute of Scientific and Technical Information of China (English)

    李宏煦; 王淀佐; 邱冠周; 胡岳华

    2004-01-01

    Thiobacillus ferrooxidans might be the most important bacteria used in biometallurgy. The foundation way of its growth process is oxidizing ferrous in order to obtain energy needed for metabolism, but the variation of ferrous concentration and mixed potential of the culture media would have crucial effect on the bacteria growth.Based on the characteristics of Thiobacillus ferrooxidans growth and redox potential of ferric and ferrous, an electrochemical cell was designed conventionally to study growth rule and the relationship between redox potential and bacteria growth was built up, and some growth kinetics of Thiobacillus ferrooxidans were elucidated. It demonstrates that the variation of open potential of electrochemical cell △E shows the growth tendency of Thiobacillus ferrooxidans, at the initial growth stage, the value of △E increases slowly, when at logistic growth stage, it increases drastically, and the growth rate of bacteria is linear with the oxidation rate of ferrous. The bacteria growth kinetics model is proposed using Monod and Michealis-Menten equation, and the kinetics parameters are got. The consistence of the measured and the calculated results proves that it is proper to use the proposed kinetics model and the electrochemical cell method to describe the growth rule of Thiobacillus ferrooxidans.

  1. Manipulation of pyrite colonization and leaching by iron-oxidizing Acidithiobacillus species.

    Science.gov (United States)

    Bellenberg, Sören; Barthen, Robert; Boretska, Mariia; Zhang, Ruiyong; Sand, Wolfgang; Vera, Mario

    2015-02-01

    In this study, the process of pyrite colonization and leaching by three iron-oxidizing Acidithiobacillus species was investigated by fluorescence microscopy, bacterial attachment, and leaching assays. Within the first 4-5 days, only the biofilm subpopulation was responsible for pyrite dissolution. Pyrite-grown cells, in contrast to iron-grown cells, were able to oxidize iron(II) ions or pyrite after 24 h iron starvation and incubation with 1 mM H₂O₂, indicating that these cells were adapted to the presence of enhanced levels of reactive oxygen species (ROS), which are generated on metal sulfide surfaces. Acidithiobacillus ferrivorans SS3 and Acidithiobacillus ferrooxidans R1 showed enhanced pyrite colonization and biofilm formation compared to A. ferrooxidans (T). A broad range of factors influencing the biofilm formation on pyrite were also identified, some of them were strain-specific. Cultivation at non-optimum growth temperatures or increased ionic strength led to a decreased colonization of pyrite. The presence of iron(III) ions increased pyrite colonization, especially when pyrite-grown cells were used, while the addition of 20 mM copper(II) ions resulted in reduced biofilm formation on pyrite. This observation correlated with a different extracellular polymeric substance (EPS) composition of copper-exposed cells. Interestingly, the addition of 1 mM sodium glucuronate in combination with iron(III) ions led to a 5-fold and 7-fold increased cell attachment after 1 and 8 days of incubation, respectively, in A. ferrooxidans (T). In addition, sodium glucuronate addition enhanced pyrite dissolution by 25%.

  2. Bioleaching of metals from steel slag by Acidithiobacillus thiooxidans culture supernatant.

    Science.gov (United States)

    Hocheng, Hong; Su, Cheer; Jadhav, Umesh U

    2014-12-01

    The generation of 300–500 kg of slag per ton of the steel produced is a formidable amount of solid waste available for treatment. They usually contain considerable quantities of valuable metals. In this sense, they may become either important secondary resource if processed in eco-friendly manner for secured supply of contained metals or potential pollutants, if not treated properly. It is possible to recover metals from steel slag by applying bioleaching process. Electric arc furnace (EAF) slag sample was used for bioleaching of metals. In the present study, before bioleaching experiment water washing of an EAF slag was carried out. This reduced slag pH from 11.2 to 8.3. Culture supernatants of Acidithiobacillus thiooxidans (At. thiooxidans), Acidithiobacillus ferrooxidans (At. ferrooxidans), and Aspergillus niger (A. niger) were used for metal solubilization. At. thiooxidans culture supernatant containing 0.016 M sulfuric acid was found most effective for bioleaching of metals from an EAF slag. Maximum metal extraction was found for Mg (28%), while it was least for Mo (0.1%) in six days. Repeated bioleaching cycles increased metal recovery from 28% to 75%, from 14% to 60% and from 11% to 27%, for Mg, Zn and Cu respectively.

  3. Thiobacillus ferrooxidans detection using immunoelectron microscopy.

    Science.gov (United States)

    Coto, O; Fernández, A I; León, T; Rodríguez, D

    1992-11-01

    A specific, fast and very sensitive immunoelectron microscopy method was developed to morphologically and serologically distinguish different cultures of iron oxidizers. Bacteria isolated from the acidic waters of "Matahambre" and "Mina Delita" mines (Cuba) were characterized. An antiserum specific to Thiobacillus ferrooxidans did not react with other bacteria also present in the acidic waters of mine drainage. Our results suggest the occurrence of some strains of Thiobacillus ferrooxidans, Thiobacillus thiooxidans and Leptospirillum ferrooxidans in these waters.

  4. [Inhibition of Low Molecular Organic Acids on the Activity of Acidithiobacillus Species and Its Effect on the Removal of Heavy Metals from Contaminated Soil].

    Science.gov (United States)

    Song, Yong-wei; Wang, He-rul; Cao, Yan-xiao; Li, Fei; Cui, Chun-hong; Zhou, Li

    2016-05-15

    Application of organic fertilizer can reduce the solubility and bioavailability of heavy metals in contaminated soil, but in the flooded anaerobic environment, organic fertilizer will be decomposed to produce a large number of low molecular organic acids, which can inhibit the biological activity of Acidithiobacillus species. Batch cultures studies showed that the monocarboxylic organic acids including formic acid, acetic acid, propionic acid, and butyric acid exhibited a marked toxicity to Acidithiobacillus species, as indicated by that 90% of inhibitory rate for Fe2 and So oxidation in 72 h were achieved at extremely low concentrations of 41.2 mg · L⁻¹, 78.3 mg · L⁻¹, 43.2 mg · L⁻¹, 123.4 mg · L⁻¹ and 81.9 mg 230. 4 mg · L⁻¹, 170.1 mg · L⁻¹, 123.4 mg · L⁻¹ respectively. Of these organic acids, formic acid was the most toxic one as indicated by that Fe2 and So oxidation was almost entirely inhibited at a low concentration. In addition, it was found that Acidithiobacillus ferrooxidans was more sensitive to low molecular organic acids than Acidithiobacillus thiooxidans. What's more, there was little effect on biological acidification process of heavy metal contaminated soil when organic acids were added at initial stage (Oh), but it was completely inhibited when these acids were added after 12 h of conventional biological acidification, thus decreasing the efficiency of heavy metals dissolution from soil.

  5. Acidithiobacillus thiooxidans secretome containing a newly described lipoprotein Licanantase enhances chalcopyrite bioleaching rate.

    Science.gov (United States)

    Bobadilla Fazzini, Roberto A; Levican, Gloria; Parada, Pilar

    2011-02-01

    The nature of the mineral-bacteria interphase where electron and mass transfer processes occur is a key element of the bioleaching processes of sulfide minerals. This interphase is composed of proteins, metabolites, and other compounds embedded in extracellular polymeric substances mainly consisting of sugars and lipids (Gehrke et al., Appl Environ Microbiol 64(7):2743-2747, 1998). On this respect, despite Acidithiobacilli-a ubiquitous bacterial genera in bioleaching processes (Rawlings, Microb Cell Fact 4(1):13, 2005)-has long been recognized as secreting bacteria (Jones and Starkey, J Bacteriol 82:788-789, 1961; Schaeffer and Umbreit, J Bacteriol 85:492-493, 1963), few studies have been carried out in order to clarify the nature and the role of the secreted protein component: the secretome. This work characterizes for the first time the sulfur (meta)secretome of Acidithiobacillus thiooxidans strain DSM 17318 in pure and mixed cultures with Acidithiobacillus ferrooxidans DSM 16786, identifying the major component of these secreted fractions as a single lipoprotein named here as Licanantase. Bioleaching assays with the addition of Licanantase-enriched concentrated secretome fractions show that this newly found lipoprotein as an active protein additive exerts an increasing effect on chalcopyrite bioleaching rate.

  6. Adaptacion de una cepa compatible con Acidithiobacillus ferrooxidans sobre concentrados de calcopirita

    National Research Council Canada - National Science Library

    Mejia, E; Ospina, J.D; Osorno, B.L; Marquez, M.A; Morales, A.L

    2011-01-01

    ... de particula, -200 y -325 serie Tyler de tamices. Los microorganismos fueron adaptados por la disminucion gradual de la fuente principal de energia, sulfato ferroso, y el aumento en el contenido de mineral, para finalmente realizar un subcultivo...

  7. Bioflotation of pyrite with Thiobacillus ferrooxidans

    Institute of Scientific and Technical Information of China (English)

    Shaoxian Song; Yimin Zhang; Shouci Lu

    2004-01-01

    Bioflotation of pyrite with bacteria Thiobacillus ferrooxidans in the presence or absence of potassium ethyl xanthate was studied on a pure pyrite through microflotation and electrophoretic light scattering measurements. The experimental results showed that in the absence of xanthate, pyrite flotation is slightly enhanced by Thiobacillus ferrooxidans. However, with xanthate as a collector, pyrite flotation is strongly depressed after being exposed to the bacteria. The longer is the time when the pyrite is exposed to the bacteria, the stronger the depression is. The mechanism of the depression might be due to the formation of the biofilms of Thiobacillus ferrooxidans on pyrite surfaces, preventing the adsorption of xanthate on pyrite surfaces in the form of dixanthogen or xanthate ions.

  8. Molecular Systematics of the Genus Acidithiobacillus: Insights into the Phylogenetic Structure and Diversification of the Taxon

    Science.gov (United States)

    Nuñez, Harold; Moya-Beltrán, Ana; Covarrubias, Paulo C.; Issotta, Francisco; Cárdenas, Juan Pablo; González, Mónica; Atavales, Joaquín; Acuña, Lillian G.; Johnson, D. Barrie; Quatrini, Raquel

    2017-01-01

    The acidithiobacilli are sulfur-oxidizing acidophilic bacteria that thrive in both natural and anthropogenic low pH environments. They contribute to processes that lead to the generation of acid rock drainage in several different geoclimatic contexts, and their properties have long been harnessed for the biotechnological processing of minerals. Presently, the genus is composed of seven validated species, described between 1922 and 2015: Acidithiobacillus thiooxidans, A. ferrooxidans, A. albertensis, A. caldus, A. ferrivorans, A. ferridurans, and A. ferriphilus. However, a large number of Acidithiobacillus strains and sequence clones have been obtained from a variety of ecological niches over the years, and many isolates are thought to vary in phenotypic properties and cognate genetic traits. Moreover, many isolates remain unclassified and several conflicting specific assignments muddle the picture from an evolutionary standpoint. Here we revise the phylogenetic relationships within this species complex and determine the phylogenetic species boundaries using three different typing approaches with varying degrees of resolution: 16S rRNA gene-based ribotyping, oligotyping, and multi-locus sequencing analysis (MLSA). To this end, the 580 16S rRNA gene sequences affiliated to the Acidithiobacillus spp. were collected from public and private databases and subjected to a comprehensive phylogenetic analysis. Oligotyping was used to profile high-entropy nucleotide positions and resolve meaningful differences between closely related strains at the 16S rRNA gene level. Due to its greater discriminatory power, MLSA was used as a proxy for genome-wide divergence in a smaller but representative set of strains. Results obtained indicate that there is still considerable unexplored diversity within this genus. At least six new lineages or phylotypes, supported by the different methods used herein, are evident within the Acidithiobacillus species complex. Although the diagnostic

  9. 元素硫对黄铜矿生物浸出行为及群落结构的影响%Relationships among bioleaching performance, additional elemental sulfur,microbial population dynamics and its energy metabolism in bioleaching of chalcopyrite

    Institute of Scientific and Technical Information of China (English)

    夏乐先; 汤露; 夏金兰; 尹礎; 柴立元; 赵小娟; 聂珍媛; 柳建设; 邱冠周

    2012-01-01

    To estimate the relationships among bioleaching performance,additional elemental sulfur (S0),microbial population dynamics and its energy metabolism,bioleaching of chalcopyrite by three typical sulfur- and/or iron-oxidizing bacteria,Acidithiobacillus ferrooxidans,Leptospirillum ferriphilum and Acidithiobacillus thiooxidans with different levels of sulfur were studied in batch shake flask cultures incubated at 30 ℃.Copper dissolution capability (71%) was increased with the addition of 3.193 g/L S0,compared to that (67%) without S0.However,lower copper extraction was obtained in bioleaching with excessive sulfur.Microbial population dynamics during chalcopyrite bioleaching process was monitored by using PCR-restrietion fragment length polymorphism (PCR-RFLP).Additional S0 accelerated the growth of sulfur-oxidizing bacteria,inhibited the iron-oxidizing metabolism and led to the decrease of iron-oxidizing microorganisms,finally affected iron concentration,redox potential and bioleaching performance.It is suggested that mixed iron and sulfur-oxidizing microorganisms with further optimized additional S0 concentration could improve copper recovery from chalcopyrite.%研究3种典型铁/硫代谢菌-Acidithiobacillus ferrooxidans,Leptospirillum ferriphilum及Acidithiobacillus thiooxidans混合浸出黄铜矿过程中铁/硫氧化活性、群落结构(PCR-RFLP)的变化,以及不同浓度的元素硫对其影响.结果发现,加入3.193 g/L元素硫能促进细菌的表观硫氧化活性,改变浸矿体系的群落结构,并进一步影响钝化层的形成、金属离子的溶出,其浸出率(71%)较未添加硫的(67%)有一定程度的提高.而过量的元素硫会抑制铜的浸出(浸出率44%).

  10. Mechanism of arsenic tolerance and bioremoval of arsenic by Acidithiobacilus ferrooxidans

    Directory of Open Access Journals (Sweden)

    Chandra Prabha M N

    2011-08-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 This paper reports the studies on mechanism of arsenic tolerance and bioremoval of arsenic ions (arsenite or arsenate by Acidithiobacillus ferrooxidans. Exposure of cells to arsenic ions resulted in increased cell surface hydrophobicity, decreased electrophoretic mobility and stronger adsorption affinity towards arsenopyrite. The mechanism of tolerance to arsenic ions were specific and could be attributed to the changes in specific protein expression in the outer membrane and cytosolic membrane fractions. Biosorption studies showed decrease in solution arsenic concentration only with ferrous–grown cells indicating that presence of ferric ions in the EPS was necessary for binding or entrapment of arsenic ions in the EPS. Bacterial EPS of ferrous–grown wild cells were able to uptake arsenate ions due to the strong affinity of ferric ions towards arsenate ions. Neither cells nor the ferric ions were capable of precipitating or oxidizing arsenite ions directly. Both arsenate ions and arsenite ions were co–precipitated with ferric ions formed during the growth of the bacteria.  

  11. Biosynthesis of bifunctional iron oxyhydrosulfate by Acidithiobacillus ferroxidans and their application to coagulation and adsorption.

    Science.gov (United States)

    Gan, Min; Song, Zibo; Jie, Shiqi; Zhu, Jianyu; Zhu, Yaowu; Liu, Xinxing

    2016-02-01

    Coagulation and adsorption are important environmental technologies, which were widely applied in water treatment. In this study, a type of villous iron oxyhydrosulfate with low crystallinity, high content iron, sulfate and hydroxyl was synthesized by Acidithiobacillus ferrooxidans, which possessed coagulation and heavy metal adsorption ability simultaneously. The results showed that the Cu(II) adsorption capacity increased within a small range over the pH range of 3.0-5.0 but increased evidently over the range of 6.0-8.0. The maximal Cu(II) adsorption capacity of sample Af and Gf reached 50.97 and 46.08mg/g respectively. The optimum pH for Cr(VI) adsorption was 6.0, and the maximal adsorption capacity reached 51.32 and 59.57mg/g. The Langmuir isotherm can better describe the adsorption behavior of Cr(VI). Coagulation performance of the iron oxyhydrosulfate (Sh) has been significantly enhanced by polysilicic acid (PSA), which was mainly determined by PSA/Sh ratio, pH and coagulant dosage. Coagulation efficiency maintained approximately at 98% when the PSA/Sh ratio ranged from 0.4/0.1 to 1.0/0.1. Polysilicic acid worked efficiently in wide pH range extending, from 2 to 3.5. Coagulation performance improved significantly with the increasing of the coagulant dosage at lower dosage range, while, at higher dosage range, the improvement was not evident even with more coagulant addition.

  12. THE DEPRESSION OF PYRITE FLOTATION BY THIOBACILLUS FERROOXIDANS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The experimental studies on the microbial flotation of a pure pyrite sample using Thiobacillus ferrooxidans was conducted in the laboratory. The results indicate that Thiobacillus ferrooaidans has strong depression effect on the flotation of pyrite. Thiobacillus f errooxidans can adsorb on the surface of pyrite in a very short time (a few min. ), changing the surface from hydrophobic into hydrophilic and making the pyrite particles to lose their floatability. Therefore, Thiobacillus ferrooxidans is an effective microbial depressant of pyrite. It has also been pointed out that the depression of pyrite by Thiobacillus ferrooxidans is caused by the adsorption of the microbial colloids, but not by the oxidation effect.

  13. Bioleaching of Copper Sulfide Ore by Acidithiobacillus Ferrooxidans and Acidithiobacillus Thiooxidans%中温嗜酸硫杆菌浸出低品位硫化铜矿

    Institute of Scientific and Technical Information of China (English)

    张雁生; 覃文庆; 王军; 任浏祎; 何名飞

    2007-01-01

    研究了中温嗜酸硫杆菌的生长条件,对黄铜矿进行了细菌浸出试验研究.研究表明,中温嗜酸硫杆菌最适宜的生长条件为:pH值为2,温度为30±1℃,此条件下细菌浓度为2.24×107个/mL.接种量、矿浆浓度对黄铜矿中铜的浸出率有显著的影响,随着接种量的增加,铜的浸出率提高.在相同浸出时间内,矿浆浓度5%左右时,黄铜矿中铜的浸出率最高.低品位硫化铜矿柱浸试验结果表明:细菌浸出75 d,铜的浸出率为45%.

  14. Ferrous ion oxidation by Thiobacillus ferrooxidans immobilized on activated carbon

    Institute of Scientific and Technical Information of China (English)

    ZHOU Ji-kui; QIN Wen-qing; NIU Yin-jian; LI Hua-xia

    2006-01-01

    The immobilization of Thiobacillus ferrooxidans on the activated carbon particles as support matrix was investigated. Cycling batch operation results in the complete oxidation of ferrous iron in 8 d when the modified 9 K medium is set to flow through the mini-bioreactor at a rate of 0.104 L/h at 25 ℃. The oxidation rate of ferrous iron with immobilized T. ferrooxidans is 9.38 g/(L·h). The results show that the immobilization of T. ferrooxidans on activated carbon can improve the rate of oxidation of ferrous iron. The SEM images show that a build-up of cells of T. ferrooxidans and iron precipitates is formed on the surface of activated carbon particles.

  15. Single and cooperative bioleaching of sphalerite by two kinds of bacteria——Acidithiobacillus ferriooxidans and Acidithiobacillus thiooxidans

    Institute of Scientific and Technical Information of China (English)

    XIA Le-xian; LIU Jian-she; XIAO Li; ZENG Jia; LI Ban-mei; GENG Mei-mei; QIU Guan-zhou

    2008-01-01

    A cooperative bioleaching (Acidithiobacillus ferriooxidans and Acidithiobacillus thiooxidans) and single bioleaching (Acidithiobacillus ferriooxidans or Acidithiobacillus thiooxidans) of sphalerite were investigated by X-ray diffractometry, energy dispersive spectrography and scanning electron microscopy. The experimental results show that the leaching rate of zinc in the mixed culture is higher than that in pure culture and the sterile control. In these processes, two kinds of bacteria perform different functions and play a cooperative role during leaching of sphalerite. The bioleaching action carried out by Acidithiobacillus ferriooxidans (A. ferriooxidans) is not directly performed through Fe2+ but Fe3+, and its role is to oxidize Fe2+ to Fe 3+ and maintain a high redox potential. Moreover, the addition of an appropriate concentration of ferric iron to the leaching systems is beneficial to zinc dissolution. In the leaching systems without Acidithiobacillus thiooxidans (A. thiooxidans), elemental sulfur layers are formed on mineral surface during the dissolution of zinc and block continuous leaching. Acidithiobacillus thiooxidans, however, eliminate the passivation and cause the bioleaching process to continue in the leaching systems. At the same time, protons from the bacterial oxidization of the elemental sulfur layers also accelerate the leaching of zinc.

  16. Mecanismo de selección de consorcios bacterianos compatibles con A. ferrooxidans y A. thiooxidans en procesos de biodesulfurización de carbón

    Directory of Open Access Journals (Sweden)

    Gerardo Andrés Caicedo

    2010-01-01

    Full Text Available A nivel de erlenmeyer, se evaluaron procesos de biodesulfurización de un carbón rico en azufre con un tamaño de partícula entre 0,24 cm - 0,06 cm, empleando consorcios bacterianos de cepas compatibles con Acidithiobacillus ferrooxidans y compatibles con Acidithiobacillus thiooxidans. Se analizaron los principales factores fisicoquímicos que pueden influir, con monitoreos de pH, potencial redox en el líquido lixiviante y sulfato en solución y precipitado, producido a partir de compuestos reducidos de azufre presentes en el carbón y en el medio. De acuerdo con los resultados obtenidos, se alcanzó 71,50% de sulfato producido con relación al máximo posible después de 16 días de proceso. Estos resultados son claves para la escogencia de cepa a la hora de trabajar procesos de biodesulfurización a escala mayor.

  17. Evidence of biogenic corrosion of titanium after exposure to a continuous culture of thiobacillus ferrooxidans grown in thiosulfate medium

    Energy Technology Data Exchange (ETDEWEB)

    Horn, J M; Martin, S I; Masterson, B

    2000-12-07

    Experiments were undertaken to evaluate extreme conditions under which candidate materials intended for use in a proposed nuclear waste repository might be susceptible to corrosion by endogenous microorganisms. Thiobucillus ferrooxidans, a sulfur-oxidizing bacterium, was grown in continuous culture using thiosulfate as an energy source; thiosulfate is oxidized to sulfate as a metabolic endproduct by this organism. Culture conditions were optimized to produce a high-density, metabolically active culture throughout a period of long term incubation in the presence of Alloy 22 (a high nickel-based alloy) and Titanium grade 7 (Tigr7) material coupons. After seven months incubation under these conditions, material coupons were withdrawn and analyzed by high resolution microscopy and energy dispersive x-ray analyses. Alloy 22 coupons showed no detectable signs of corrosion. Tigr7, however, demonstrated distinct roughening of the coupon surface, and [presumably solubilized and precipitated] titanium was detected on Alloy 22 coupons incubated in the same T. ferrooxiduns culture vessel. Control coupons of these materials incubated in sterile thiosulfate medium did not demonstrate any signs of corrosion, thus showing that observed corrosive effects were due to the T. ferrooxidans metabolic activities. T. ferrooxidans intermediates of thiosulfate oxidation or sulfate may have caused the corrosive effects observed on Tigr7.

  18. Biosorption of Cu by Thiobacillus ferrooxidans

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz-Manriquez, A. [Departamento de Ingenieria Quimica y Metalurgia, Universidad de Sonora, Hermosillo (Mexico); Magana, P.I. [Departamento de Biotecnologia y Bioingenieria, Centro de Investigacion y Estudios Avanzados (Mexico); Lopez, V. [Departamento de Biotecnologia y Bioingenieria, Centro de Investigacion y Estudios Avanzados (Mexico); Guzman, R. [Department of Chemical and Environmental Engineering, University of Arizona, Tucson (United States)

    1998-02-01

    Current technologies for removal and recovery of both toxic and industrial interest metals usually produce wastes with high concentrations of those substances. They are an important source of environmental pollution, specially when they contain heavy metals. This is one of the most important environmental problems, and of the most difficult to solve. So far, there have been a number of studies considering the possibility of removing and recovering heavy metals from diluted solutions. These are due, principally, because of the commercial value of some metals as well as the environmental impact caused by them. The traditional methods for removing have several disadvantages when metals are present in concentrations lower than 100 mg/l. Biosorption, which uses biological materials as adsorbents, has been considered as an alternative method. In this work, several variables that affect the capacity for copper biosorption by T. ferrooxidans have been studied. Particularly, the effect of pH, chemical pretreatment, biomass concentration and temperature have been considered. Results indicate that a capacity as high as 119 mg of Cu/g of dry biomass can be obtained at a temperature of 25 C. (orig.) With 6 figs., 1 tab., 13 refs.

  19. Microbial desulfurization of coal by Thiobacillus ferrooxidans and thermophilic archaea

    Energy Technology Data Exchange (ETDEWEB)

    Olsson, G.; Pott, B.-M.; Larsson, L.; Holst, O.; Karlsson, H.T. (Univ. of Lund, Lund (Sweden). Dept. of Chemical Engineering II, Chemical Center)

    1994-11-01

    Several different microorganisms have been suggested for desulfurization. In the present investigation, the thermophilic archaea [ital Acidianus brierleyi] (DSM 1651), [ital Sulfolobus acidocaldarius] (DSM 639) and [ital Sulfolobus solfataricus] (DSM 1616) were compared with the mesophyilic bacterium [ital Thiobacillus ferrooxidans] (DSM 583) concerning their capability of removing sulfur from coal. The desulfurization rate as well as the amount of sulfur removed by the microorganisms was studied. Two of the investigated microorganisms [ital Thiobacillus ferrooxidans] and [ital Acidianus brierleyi], were capable of oxidizing pure pyrite as well as oxidizing sulfur in coal. A kinetic analysis was performed assuming first order reactions. The rate constant for oxidation of pure pyrite by [ital A. brierleyi] was observed to be higher than for [ital T. ferrooxidans]. The values of the rate constants for sulfur removal from coal were comparable for the two microorganisms, but were higher than for oxidation of pure pyrite. 18 refs., 2 figs., 1 tab.

  20. Complete genome sequence of Acidimicrobium ferrooxidans type strain (ICPT)

    Energy Technology Data Exchange (ETDEWEB)

    Clum, Alicia; Nolan, Matt; Lang, Elke; Glavina Del Rio, Tijana; Tice, Hope; Copeland, Alex; Cheng, Jan-Fang; Lucas, Susan; Chen, Feng; Bruce, David; Goodwin, Lynne; Pitluck, Sam; Ivanova, Natalia; Mavrommatis, Konstantinos; Mikhailova, Natalia; Pati, Amrita; Chen, Amy; Palaniappan, Krishna; Goker, Markus; Spring, Stefan; Land, Miriam; Hauser, Loren; Chang, Yun-Juan; Jefferies, Cynthia C.; Chain, Patrick; Bristow, James; Eisen, Jonathan A.; Markowitz, Victor; Hugenholtz, Philip; Kyrpides, Nikos C.; Klenk, Hans-Peter; Lapidus, Alla

    2009-05-20

    Acidimicrobium ferrooxidans (Clark and Norris 1996) is the sole and type species of the genus, which until recently was the only genus within the actinobacterial family Acidimicrobiaceae and in the order Acidomicrobiales. Rapid oxidation of iron pyrite during autotrophic growth in the absence of an enhanced CO2 concentration is characteristic for A. ferrooxidans. Here we describe the features of this organism, together with the complete genome sequence, and annotation. This is the first complete genome sequence of the order Acidomicrobiales, and the 2,158,157 bp long single replicon genome with its 2038 protein coding and 54 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.

  1. Sulfur Oxygenase Reductase (Sor in the Moderately Thermoacidophilic Leaching Bacteria: Studies in Sulfobacillus thermosulfidooxidans and Acidithiobacillus caldus

    Directory of Open Access Journals (Sweden)

    Claudia Janosch

    2015-10-01

    Full Text Available The sulfur oxygenase reductase (Sor catalyzes the oxygen dependent disproportionation of elemental sulfur, producing sulfite, thiosulfate and sulfide. Being considered an “archaeal like” enzyme, it is also encoded in the genomes of some acidophilic leaching bacteria such as Acidithiobacillus caldus, Acidithiobacillus thiooxidans, Acidithiobacillus ferrivorans and Sulfobacillus thermosulfidooxidans, among others. We measured Sor activity in crude extracts from Sb. thermosulfidooxidans DSM 9293T. The optimum temperature for its oxygenase activity was achieved at 75 °C, confirming the “thermophilic” nature of this enzyme. Additionally, a search for genes probably involved in sulfur metabolism in the genome sequence of Sb. thermosulfidooxidans DSM 9293T was done. Interestingly, no sox genes were found. Two sor genes, a complete heterodisulfidereductase (hdr gene cluster, three tetrathionate hydrolase (tth genes, three sulfide quinonereductase (sqr, as well as the doxD component of a thiosulfate quinonereductase (tqo were found. Seven At. caldus strains were tested for Sor activity, which was not detected in any of them. We provide evidence that an earlier reported Sor activity from At. caldus S1 and S2 strains most likely was due to the presence of a Sulfobacillus contaminant.

  2. Sulfur Oxygenase Reductase (Sor) in the Moderately Thermoacidophilic Leaching Bacteria: Studies in Sulfobacillus thermosulfidooxidans and Acidithiobacillus caldus

    Science.gov (United States)

    Janosch, Claudia; Remonsellez, Francisco; Sand, Wolfgang; Vera, Mario

    2015-01-01

    The sulfur oxygenase reductase (Sor) catalyzes the oxygen dependent disproportionation of elemental sulfur, producing sulfite, thiosulfate and sulfide. Being considered an “archaeal like” enzyme, it is also encoded in the genomes of some acidophilic leaching bacteria such as Acidithiobacillus caldus, Acidithiobacillus thiooxidans, Acidithiobacillus ferrivorans and Sulfobacillus thermosulfidooxidans, among others. We measured Sor activity in crude extracts from Sb. thermosulfidooxidans DSM 9293T. The optimum temperature for its oxygenase activity was achieved at 75 °C, confirming the “thermophilic” nature of this enzyme. Additionally, a search for genes probably involved in sulfur metabolism in the genome sequence of Sb. thermosulfidooxidans DSM 9293T was done. Interestingly, no sox genes were found. Two sor genes, a complete heterodisulfidereductase (hdr) gene cluster, three tetrathionate hydrolase (tth) genes, three sulfide quinonereductase (sqr), as well as the doxD component of a thiosulfate quinonereductase (tqo) were found. Seven At. caldus strains were tested for Sor activity, which was not detected in any of them. We provide evidence that an earlier reported Sor activity from At. caldus S1 and S2 strains most likely was due to the presence of a Sulfobacillus contaminant. PMID:27682113

  3. Pyrite Surface after Thiobacillus ferrooxidans Leaching at 30℃

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In order to investigate the effect of Thiobacillus ferrooxidans on the oxidation of pyrite, two parallel experiments, which employed H2SO4 solutions and acidic solutions inoculated with Thiobacillus ferrooxidans, were designed and carried out at 30℃. The initial pH of the two solutions was adjusted to 2.5 by dropwise addition of concentrated sulphuric acid. The surfaces of pyrite before exposure to leaching solutions and after exposure to the H2SO4 solutions and acidic solutions inoculated with Thiobacillus ferrooxidans were observed by scanning electron microscopy (SEM). There were a variety of erosion patterns by Thiobacillusferrooxidans on the bio-leached pyrite surfaces. A conclusion can be drawn that the oxidation of pyrite might have been caused by erosion of the surfaces.Attachment of the bacteria to pyrite surfaces resulted in erosion pits, leading to the oxidation of pyrite.It is possible that the direct mechanism plays the most important role in the oxidation of pyrite. The changes in iron ion concentrations of both the experimental solutions with time suggest that Thiobacillus ferrooxidans can enhance greatly the oxidation of pyrite.

  4. Genome Analysis of the Biotechnologically Relevant Acidophilic Iron Oxidising Strain JA12 Indicates Phylogenetic and Metabolic Diversity within the Novel Genus "Ferrovum".

    Directory of Open Access Journals (Sweden)

    Sophie R Ullrich

    Full Text Available Members of the genus "Ferrovum" are ubiquitously distributed in acid mine drainage (AMD waters which are characterised by their high metal and sulfate loads. So far isolation and microbiological characterisation have only been successful for the designated type strain "Ferrovum myxofaciens" P3G. Thus, knowledge about physiological characteristics and the phylogeny of the genus "Ferrovum" is extremely scarce.In order to access the wider genetic pool of the genus "Ferrovum" we sequenced the genome of a "Ferrovum"-containing mixed culture and successfully assembled the almost complete genome sequence of the novel "Ferrovum" strain JA12.The genome-based phylogenetic analysis indicates that strain JA12 and the type strain represent two distinct "Ferrovum" species. "Ferrovum" strain JA12 is characterised by an unusually small genome in comparison to the type strain and other iron oxidising bacteria. The prediction of nutrient assimilation pathways suggests that "Ferrovum" strain JA12 maintains a chemolithoautotrophic lifestyle utilising carbon dioxide and bicarbonate, ammonium and urea, sulfate, phosphate and ferrous iron as carbon, nitrogen, sulfur, phosphorous and energy sources, respectively.The potential utilisation of urea by "Ferrovum" strain JA12 is moreover remarkable since it may furthermore represent a strategy among extreme acidophiles to cope with the acidic environment. Unlike other acidophilic chemolithoautotrophs "Ferrovum" strain JA12 exhibits a complete tricarboxylic acid cycle, a metabolic feature shared with the closer related neutrophilic iron oxidisers among the Betaproteobacteria including Sideroxydans lithotrophicus and Thiobacillus denitrificans. Furthermore, the absence of characteristic redox proteins involved in iron oxidation in the well-studied acidophiles Acidithiobacillus ferrooxidans (rusticyanin and Acidithiobacillus ferrivorans (iron oxidase indicates the existence of a modified pathway in "Ferrovum" strain JA12

  5. Comparative Genomics of the Extreme Acidophile Acidithiobacillus thiooxidans Reveals Intraspecific Divergence and Niche Adaptation

    Directory of Open Access Journals (Sweden)

    Xian Zhang

    2016-08-01

    Full Text Available Acidithiobacillus thiooxidans known for its ubiquity in diverse acidic and sulfur-bearing environments worldwide was used as the research subject in this study. To explore the genomic fluidity and intraspecific diversity of Acidithiobacillus thiooxidans (A. thiooxidans species, comparative genomics based on nine draft genomes was performed. Phylogenomic scrutiny provided first insights into the multiple groupings of these strains, suggesting that genetic diversity might be potentially correlated with their geographic distribution as well as geochemical conditions. While these strains shared a large number of common genes, they displayed differences in gene content. Functional assignment indicated that the core genome was essential for microbial basic activities such as energy acquisition and uptake of nutrients, whereas the accessory genome was thought to be involved in niche adaptation. Comprehensive analysis of their predicted central metabolism revealed that few differences were observed among these strains. Further analyses showed evidences of relevance between environmental conditions and genomic diversification. Furthermore, a diverse pool of mobile genetic elements including insertion sequences and genomic islands in all A. thiooxidans strains probably demonstrated the frequent genetic flow (such as lateral gene transfer in the extremely acidic environments. From another perspective, these elements might endow A. thiooxidans species with capacities to withstand the chemical constraints of their natural habitats. Taken together, our findings bring some valuable data to better understand the genomic diversity and econiche adaptation within A. thiooxidans strains.

  6. Comparative Genomics of the Extreme Acidophile Acidithiobacillus thiooxidans Reveals Intraspecific Divergence and Niche Adaptation.

    Science.gov (United States)

    Zhang, Xian; Feng, Xue; Tao, Jiemeng; Ma, Liyuan; Xiao, Yunhua; Liang, Yili; Liu, Xueduan; Yin, Huaqun

    2016-08-19

    Acidithiobacillus thiooxidans known for its ubiquity in diverse acidic and sulfur-bearing environments worldwide was used as the research subject in this study. To explore the genomic fluidity and intraspecific diversity of Acidithiobacillus thiooxidans (A. thiooxidans) species, comparative genomics based on nine draft genomes was performed. Phylogenomic scrutiny provided first insights into the multiple groupings of these strains, suggesting that genetic diversity might be potentially correlated with their geographic distribution as well as geochemical conditions. While these strains shared a large number of common genes, they displayed differences in gene content. Functional assignment indicated that the core genome was essential for microbial basic activities such as energy acquisition and uptake of nutrients, whereas the accessory genome was thought to be involved in niche adaptation. Comprehensive analysis of their predicted central metabolism revealed that few differences were observed among these strains. Further analyses showed evidences of relevance between environmental conditions and genomic diversification. Furthermore, a diverse pool of mobile genetic elements including insertion sequences and genomic islands in all A. thiooxidans strains probably demonstrated the frequent genetic flow (such as lateral gene transfer) in the extremely acidic environments. From another perspective, these elements might endow A. thiooxidans species with capacities to withstand the chemical constraints of their natural habitats. Taken together, our findings bring some valuable data to better understand the genomic diversity and econiche adaptation within A. thiooxidans strains.

  7. Bacterial leaching of a sulfide ore by Thiobacillus ferrooxidans and Thiobacillus thiooxidans: I. Shake flask studies.

    Science.gov (United States)

    Lizama, H M; Suzuki, I

    1988-06-20

    Bacterial leaching of a sulfide ore containing pyrite, chalcopyrite, and sphalerite was studied in shake flask experiments using Thiobacillus ferrooxidans and Thiobacillus thiooxidans strains isolated from mine sites. The Fe(2+)grown T. ferrooxidans isolates solubilized sphalerite preferentially over chalcopyrite leaching 7-10% Cu, 68-76% Zn, and 10-22% Fe from the ore in 18 days. The sulfur grown T. thiooxidans isolates leached Zn much more slowly and very little Fe, with a Cu-Zn extraction ratio twice the value obtained with T. ferrooxidans. The ore adapted T. ferrooxidans started solubilizing Cu and Zn without a lag period. The ore-adapted T. thiooxidans extracted Cu as well as T. ferrooxidans, but the extraction of Zn or Fe was still much slower in the low-phosphate medium, while in the high-phosphate medium it approached the value obtained with T. ferrooxidans. A high Cu-Zn extraction ratio of 0.34 was obtained with T. thiooxidans in the low phosphate medium. In the mixed-culture experiments with T. ferrooxidans and T. thiooxidans, the culture behaved as T. thiooxidans in the low-phosphate medium with a higher Cu-Zn extraction ratio and as T. ferrooxidans in the high-phosphate medium with a lower Cu-Zn extraction ratio. It is concluded that T. ferrooxidans and T. thiooxidans solubilize sulfide minerals by different mechanisms.

  8. Complete genome sequence of Acidimicrobium ferrooxidans type strain (ICPT)

    Energy Technology Data Exchange (ETDEWEB)

    Clum, Alicia [U.S. Department of Energy, Joint Genome Institute; Nolan, Matt [U.S. Department of Energy, Joint Genome Institute; Lang, Elke [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Glavina Del Rio, Tijana [U.S. Department of Energy, Joint Genome Institute; Tice, Hope [U.S. Department of Energy, Joint Genome Institute; Copeland, A [U.S. Department of Energy, Joint Genome Institute; Cheng, Jan-Fang [U.S. Department of Energy, Joint Genome Institute; Lucas, Susan [U.S. Department of Energy, Joint Genome Institute; Chen, Feng [U.S. Department of Energy, Joint Genome Institute; Bruce, David [U.S. Department of Energy, Joint Genome Institute; Goodwin, Lynne A. [Los Alamos National Laboratory (LANL); Pitluck, Sam [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; Goker, Markus [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Spring, Stefan [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Land, Miriam L [ORNL; Hauser, Loren John [ORNL; Chang, Yun-Juan [ORNL; Jeffries, Cynthia [Oak Ridge National Laboratory (ORNL); Chain, Patrick S. G. [Lawrence Livermore National Laboratory (LLNL); 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; Lapidus, Alla L. [U.S. Department of Energy, Joint Genome Institute

    2009-01-01

    Acidimicrobium ferrooxidans (Clark and Norris 1996) is the sole and type species of the ge-nus, which until recently was the only genus within the actinobacterial family Acidimicrobia-ceae and in the order Acidomicrobiales. Rapid oxidation of iron pyrite during autotrophic growth in the absence of an enhanced CO2 concentration is characteristic for A. ferrooxidans. Here we describe the features of this organism, together with the complete genome se-quence, and annotation. This is the first complete genome sequence of the order Acidomi-crobiales, and the 2,158,157 bp long single replicon genome with its 2038 protein coding and 54 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.

  9. Biological effect of Acidithiobacillus thiooxidans on some potentially toxic elements during alteration of SON 68 nuclear glass

    Science.gov (United States)

    Bachelet, M.; Crovisier, J. L.; Stille, P.; Vuilleumier, S.; Geoffroy, V.

    2009-04-01

    Although underground nuclear waste repositories are not expected to be favourable places for microbial activity, one should not exclude localized action of extremophilic bacteria on some materials involved in the storage concept. Among endogenous or accidentally introduced acidophiles, some are susceptible to lead to a locally drastic decreased in pH, with potential consequences on materials corrosion. Experiments were performed with Acidithiobacillus thiooxidans on 100-125 m french reference nuclear glass SON68 grains in a mineral medium under static conditions during 60 days at 25degC. Growth medium was periodically renewed and analyzed by ICP-AES and ICP-MS spectrometry for both major, trace and ultra-trace elements. Biofilm formation was evidenced by confocal laser microscopy, staining DNA with ethidium bromide and exopolysaccharides with calcofluor white. Biofilm thickness around material grains exceeded 20 m under the chosen experimental conditions. It can be noticed that while numerous studies on biofilm formation upon interaction between Acidithiobacillus ferrooxidans and materials are found in the literature, evidence for biofilm formation is still scarce for the case of the acidophilic bacterium A. thiooxidans. Presence of biofilm is a key parameter for material alteration at the solid/solution interface in biotic systems. Indeed, various constitutive elements of materials trapped in the polyanionic polymer of biofilm may also influence the alteration process. In particular, biofilm may reduce the alteration rate of materials by forming a protective barrier at their surface (Aouad et al., 2008). In this study, glass alteration rates, determined using strontium as tracer, showed that the progressive formation of a biofilm on the surface of glass has a protective effect against its alteration. Uranium and rare earth elements (REE) are efficiently trapped in the biogenic compartment of the system (exopolysaccharides + bacterial cells). Besides, the ratio

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

    Science.gov (United States)

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

    2006-12-01

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

  11. Immobilisation of Thiobacillus ferrooxidans cells on nickel alloy fibre for ferrous sulfate oxidation.

    Science.gov (United States)

    Gómez, J M; Cantero, D; Webb, C

    2000-09-01

    The immobilisation of the iron-oxidising bacteria Thiobacillus ferrooxidans on nickel alloy fibre as support is described. This matrix showed promise for application in iron oxidation under strongly acidic conditions. The influence on the colonisation process of T. ferrooxidans exerted by the initial pH of the medium and by temperature has also been studied. Results showed that immobilisation of T. ferrooxidans cells was affected by changes of temperature between 30 degrees C and 40 degrees C and in pH from 1.4 to 2.0.

  12. Electrochemical behavior of chalcopyrite in presence of Thiobacillus ferrooxidans

    Institute of Scientific and Technical Information of China (English)

    LI Hong-xu; QIU Guan-zhou; HU Yue-hua; CANG Da-qiang; WANG Dian-zuo

    2006-01-01

    The chalcopyrite anode dissolution behavior in the presence or absence of bacteria in 9 K media using bacteria modified powder microelectrode at 30 ℃ was studied. It is found that during the anode dissolution, many intermediate transient reactions occur accompanying with the production of chalcocite and covellite at potential between -0.075 V and -0.025 V (vs SCE). At low scanning potential between -0.1 and -0.250 V, the iron ion is released in ferrous form, but at the relative high potential up to 0.7 V, it is the ferric one. The presence of Thiobacillus ferrooxidans makes peak current increase and the initial peak potential negatively move, hinting the decomposed oxidation reaction easily occurred and especially the iron ion released and ferrous oxidation reaction enhanced. The characteristic at potential between -0.75 and -0.5 V demonstrates the Thiobacillus ferrooxidans also contributes to the element sulfur formed on the oxidation surface and removed during anode process. The added ferric in the cell could enhance the dissolution reaction, while the increased acid under pH=2 might slightly hamper the process. The anode dissolution kinetics studies show that the presence of bacteria could decease corrosion potential from 0.238 V to 0.184 V and increase the corrosion current density from 1.632 14×10-8 A/cm2 to 2.374 11×10-7A/cm2.

  13. Inhibition of Low Molecular Organic Acids on the Activity of Acidithiobacillus Species and Its Effect on the Removal of Heavy Metals from Contaminated Soil%低分子有机酸对硫杆菌活性的抑制作用及对土壤重金属脱除的影响

    Institute of Scientific and Technical Information of China (English)

    宋永伟; 王鹤茹; 曹艳晓; 李飞; 崔春红; 周立祥

    2016-01-01

    Application of organic fertilizer can reduce the solubility and bioavailability of heavy metals in contaminated soil, but in the flooded anaerobic environment, organic fertilizer will be decomposed to produce a large number of low molecular organic acids, which can inhibit the biological activity of Acidithiobacillus species. Batch cultures studies showed that the monocarboxylic organic acids including formic acid, acetic acid, propionic acid, and butyric acid exhibited a marked toxicity to Acidithiobacillus species, as indicated by that 90% of inhibitory rate for Fe2 + and S0 oxidation in 72 h were achieved at extremely low concentrations of 41. 2 mg.L - 1 , 78. 3 mg.L - 1 , 43. 2 mg.L - 1 , 123. 4 mg.L - 1 and 81. 9 mg.L - 1 , 230. 4 mg.L - 1 , 170. 1 mg.L - 1 , 123. 4 mg.L - 1 , respectively. Of these organic acids, formic acid was the most toxic one as indicated by that Fe2 + and S0 oxidation was almost entirely inhibited at a low concentration. In addition, it was found that Acidithiobacillus ferrooxidans was more sensitive to low molecular organic acids than Acidithiobacillus thiooxidans. What,s more, there was little effect on biological acidification process of heavy metal contaminated soil when organic acids were added at initial stage (0h), but it was completely inhibited when these acids were added after 12 h of conventional biological acidification, thus decreasing the efficiency of heavy metals dissolution from soil.%施用有机肥能够降低污染土壤重金属溶解性和生物可利用性,但在淹水厌氧等环境中,有机肥会分解产生大量低分子有机酸,会抑制嗜酸性硫杆菌的生物活性.通过摇瓶实验研究了低分子有机酸对硫杆菌的毒害抑制效果和不同硫杆菌对各类有机酸的耐受水平.结果表明,纯体系培养下,A. ferrooxidans 和 A. thiooxidans 活性抑制率在72 h 内达到90%以上,所需甲、乙、丙、丁酸最低浓度分别为41.2、78.3、43.2、123.4 mg.L -1和81.9、230.4

  14. Overproduction and substrate specificity of 3-isopropylmalate dehydrogenase from Thiobacillus ferrooxidans.

    Science.gov (United States)

    Matsunami, H; Kawaguchi, H; Inagaki, K; Eguchi, T; Kakinuma, K; Tanaka, H

    1998-02-01

    We constructed an overexpression system in Escherichia coli of the leuB gene coding for 3-isopropylmalate dehydrogenase in Thiobacillus ferrooxidans. E. coli harboring the plasmid we constructed, pKK leuB1, produced 17-fold the enzyme protein of the expression system previously used for purification. The substrate specificity of the enzyme was analyzed with synthetic (2R, 3S)-3-alkylmalates. The 3-isopropylmalate dehydrogenase of Thiobacillus ferrooxidans had broad specificity toward the alkylmalates.

  15. Biosorption of Zn(II) by Thiobacillus ferrooxidans

    Energy Technology Data Exchange (ETDEWEB)

    Celaya, R.J.; Noriega, J.A.; Yeomans, J.H.; Ruiz-Manriquez, A. [Dept. de Ingenieria Quimica y Metalurgia, Universidad de Sonora, Hermosillo (Mexico); Ortega, L.J. [Dept. de Biotecnologia y Bioingenieria, Centro de Investigacion y Estudios Avanzados (Mexico)

    2000-06-01

    There have been a number of studies considering the possibility of removing and recovering heavy metals from diluted solutions. These are due, principally, because of the commercial value of some metals as well as in the environmental impact caused by them. The traditional methods for removing have several disadvantages when metals are present in concentrations lower than 100 mg/l. Biosorption, which uses biological materials as adsorbents, has been considered as an alternative method. In this work, variables like pH and biomass chemical pretreatment have been studied for its effect on the capacity for zinc biosorption by Thiobacillus ferrooxidans. Also, studies to determinate the time for zinc adsorption were carried out. Results indicate that a capacity as high as 82.61 mg of Zn(II)/g of dry biomass can be obtained at a temperature of 25 C and that the biosorption process occurs in a time of 30 min. (orig.)

  16. 表面活性剂Tween-80对Acidithiobacillus ferrooxidans硫氧化和硫代谢相关蛋白质基因表达的影响(英文)

    Institute of Scientific and Technical Information of China (English)

    彭安安; 刘红昌; 聂珍媛; 夏金兰

    2012-01-01

    研究了表面活性剂 Tween-80 对 Acidithiobacillus ferrooxidans ATCC 23270 生长、硫氧化和硫代谢相关典型基因表达的影响。结果表明,当培养基中含有 10 2g/L Tween-80 时,A. ferrooxidans 的生长以及其对不溶性底物(S0和 CuFeS2)的代谢得到了促进。在该条件下,经过 24 d 的生物浸出,黄铜矿的铜离子浸出率比对照组(不含 Tween-80)高 16%。FT-IR 光谱分析表明,这可能是由于 Tween-80 的存在而导致胞外多聚物成分发生变化而引起的。用 RT-qPCR 来分析 17 个硫代谢相关基因在 Tween-80 存在时的表达差异。胞外蛋白质基因表达下调表明了Tween-80 对细菌硫吸附作用的影响。硫代谢相关酶基因表达水平的变化为硫代谢的研究提供了参考。

  17. Comparative Genomics of the Extreme Acidophile Acidithiobacillus thiooxidans Reveals Intraspecific Divergence and Niche Adaptation

    OpenAIRE

    Zhang, Xian; Feng, Xue; Tao, Jiemeng; Ma, Liyuan; Xiao, Yunhua; Liang, Yili; Liu, Xueduan; Yin, Huaqun

    2016-01-01

    Acidithiobacillus thiooxidans known for its ubiquity in diverse acidic and sulfur-bearing environments worldwide was used as the research subject in this study. To explore the genomic fluidity and intraspecific diversity of Acidithiobacillus thiooxidans (A. thiooxidans) species, comparative genomics based on nine draft genomes was performed. Phylogenomic scrutiny provided first insights into the multiple groupings of these strains, suggesting that genetic diversity might be potentially correl...

  18. Genome Analysis of the Biotechnologically Relevant Acidophilic Iron Oxidising Strain JA12 Indicates Phylogenetic and Metabolic Diversity within the Novel Genus “Ferrovum”

    Science.gov (United States)

    Ullrich, Sophie R.; Poehlein, Anja; Tischler, Judith S.; González, Carolina; Ossandon, Francisco J.; Daniel, Rolf; Holmes, David S.; Schlömann, Michael; Mühling, Martin

    2016-01-01

    Background Members of the genus “Ferrovum” are ubiquitously distributed in acid mine drainage (AMD) waters which are characterised by their high metal and sulfate loads. So far isolation and microbiological characterisation have only been successful for the designated type strain “Ferrovum myxofaciens” P3G. Thus, knowledge about physiological characteristics and the phylogeny of the genus “Ferrovum” is extremely scarce. Objective In order to access the wider genetic pool of the genus “Ferrovum” we sequenced the genome of a “Ferrovum”-containing mixed culture and successfully assembled the almost complete genome sequence of the novel “Ferrovum” strain JA12. Phylogeny and Lifestyle The genome-based phylogenetic analysis indicates that strain JA12 and the type strain represent two distinct “Ferrovum” species. “Ferrovum” strain JA12 is characterised by an unusually small genome in comparison to the type strain and other iron oxidising bacteria. The prediction of nutrient assimilation pathways suggests that “Ferrovum” strain JA12 maintains a chemolithoautotrophic lifestyle utilising carbon dioxide and bicarbonate, ammonium and urea, sulfate, phosphate and ferrous iron as carbon, nitrogen, sulfur, phosphorous and energy sources, respectively. Unique Metabolic Features The potential utilisation of urea by “Ferrovum” strain JA12 is moreover remarkable since it may furthermore represent a strategy among extreme acidophiles to cope with the acidic environment. Unlike other acidophilic chemolithoautotrophs “Ferrovum” strain JA12 exhibits a complete tricarboxylic acid cycle, a metabolic feature shared with the closer related neutrophilic iron oxidisers among the Betaproteobacteria including Sideroxydans lithotrophicus and Thiobacillus denitrificans. Furthermore, the absence of characteristic redox proteins involved in iron oxidation in the well-studied acidophiles Acidithiobacillus ferrooxidans (rusticyanin) and Acidithiobacillus

  19. Biodegradation of the french reference nuclear glass SON 68 by Acidithiobacillus thiooxidans : protective effect of the biofilm,U and REE retention

    Science.gov (United States)

    Bachelet, M.; Crovisier, J.; Stille, P.; Boutin, R.; Vuilleumier, S.; Geoffroy, V.

    2008-12-01

    Although underground nuclear waste repositories are not expected to be favourable places for microbial activity, one should not exclude localized action of extremophilic bacteria on some materials involved in the storage concept. Among endogenous or accidentally introduced acidophiles, some are susceptible to lead to a locally drastic decreased in pH with potential consequences on materials corrosion. Experiments were performed with Acidithiobacillus thiooxidans on 100-125 μm french reference nuclear glass SON68 grains in a mineral medium under static conditions during 60 days at 25°C. Growth medium was periodically renewed and analyzed by ICP-AES and ICP-MS spectrometry for both major, traces and ultra-traces elements. Biofilm formation was evidenced by confocal laser microscopy, staining DNA with ethidium bromide and exopolysaccharides with calcofluor white. Biofilm thickness around material grains exceeded 20 μm under the chosen experimental conditions. It can be noticed that while numerous studies on biofilm formation upon interaction between Acidithiobacillus ferrooxidans and materials can be found in the literature, evidence for biofilm formation is still scarce for the case of the acidophilic bacterium A. thiooxidans. Presence of biofilm is a key parameter for material alteration at the solid/solution interface in biotic systems. Indeed, various constitutive elements of materials trapped in the polyanionic polymer of biofilm may also influence the alteration process. In particular, biofilm may reduce the alteration rate of materials by forming a protective barrier at their surface (Aouad et al., 2008). In this study, glass alteration rates, determined using strontium, molybdenum and caesium as tracers, showed that the biofilm has a protective effect against glass alteration. U and REE are efficiently trapped in the biogenic compartment of the system (exopolysaccharides (EPS) + bacterial cells). Biofilm analysis are in progress to determine whether these

  20. Bioleaching of heavy metals from sewage sludge using Acidithiobacillus thiooxidans

    Science.gov (United States)

    Wen, Ye-Ming; Lin, Hong-Yan; Wang, Qing-Ping; Chen, Zu-Liang

    2010-11-01

    Acidithiobacillus thiooxidans was isolated from sewage sludge using the incubation in the Waksman liquor medium and the inoculation in Waksman solid plate. It was found that the optimum conditions of the bioleaching included solid concentration 2%, sulfur concentration 5 gṡL-1 and cell concentration 10%. The removal efficiency of Cr, Cu, Pb and Zh in sewage sludge, which was obtained from waste treatment plant, Jinshan, Fuzhou, was 43.65%, 96.24%, 41.61% and 96.50% in the period of 4˜10 days under the optimum conditions, respectively. After processing using the proposed techniques, the heavy metals in sewage sludge did meet the requirement the standards of nation.

  1. Bioleaching of chromium from tannery sludge by indigenous Acidithiobacillus thiooxidans.

    Science.gov (United States)

    Wang, Yuan-Shan; Pan, Zhi-Yan; Lang, Jian-Min; Xu, Jian-Miao; Zheng, Yu-Guo

    2007-08-17

    Chromium in tannery sludge will cause serious environmental problems and is toxic to organisms. The acidophilic sulfur-oxidizing Acidithiobacillus thiooxidans can leach heavy metals form urban and industrial wastes. This study examined the ability of an indigenous sulfur-oxidizing A. thiooxidans to leach chromium from tannery sludge. The results showed that the pH of sludge mixture inoculated with the indigenous A. thiooxidans decreased to around 2.0 after 4 days. After 6 days incubation in shaking flasks at 30 degrees C and 160 rpm, up to 99% of chromium was solubilized from tannery sludge. When treated in a 2-l bubble column bioreactor for 5 days at 30 degrees C and aeration of 0.5 vvm, 99.7% of chromium was leached from tannery sludge. The results demonstrated that chromium in tannery sludge can be efficiently leached by the indigenous A. thiooxidans.

  2. Obtenção e avaliação de mutantes de Acidithiobacillus ferrooxidans quanto à capacidade de lixiviar minérios de cobre

    OpenAIRE

    Costa, Mariana Araújo [UNESP

    2014-01-01

    Recent industrialization has demanded great amounts of mineral compounds copper is one of the most utilized in technological components manufacturing. The large increase in mining activities has resulted in lower grade mineral deposits. As a consequence, the demand for technical and economical solutions became critical. In this context, biohydrometalurgy, a process that uses microorganisms to perform mineral sulphide dissolution for improving metal extraction, has been pointed as a promising ...

  3. Avaliação da atividade oxidativa do Acidithiobacillus ferrooxidans sobre uma mistura composta de diferentes proporções dos sulfetos minerais pirita e calcopirita

    OpenAIRE

    Santos, Marcelo Sousa

    2011-01-01

    A diminuição gradativa, porem constante das reservas mundiais de metais no mundo, tem forçado o desenvolvimento de novas tecnologias para extração e aproveitamento destes bens minerais. A redução de custos e as novas diretrizes ambientais são o maior impulso para a busca destas novas tecnologias.A biohidrometalurgia, mais especificamente, a biolixiviação dentro deste contexto assume uma importância significativa. Os custos de operação deste processo são muito inferiores aos processos convenci...

  4. Corrosion Behaviors of Steel A3 Exposed to Thiobacillus Ferrooxidans

    Institute of Scientific and Technical Information of China (English)

    Jianhua LIU; Xin LIANG; Songmei LI

    2008-01-01

    The corrosion behaviors of steel A3 in synergistic action of Thiobacillus ferrooxidans (T.f) and electrochemically accelerated corrosion were studied by electrochemical, microbiology and surface analysis methods. The open circuit potential (Eocp) and electrochemical impedance spectroscopy (EIS) of the steel A3 electrodes were measured in leathen culture medium without and with T.f (simply called T.f solution in the following paper)in immersion electrode way at the time of the 2nd, 5th, 10th, 20th and 30th days, respectively. It was found that Eocp of the electrode for immersion in leathen culture medium shifted negatively with the immersion time while that for immersion in T.f solutions shifted negatively, then positively and finally negatively. On the 20th day, the corrosion of steel A3 for immersion in culture medium was in pitting initiation stage while that for immersion in T.f solutions was in pitting growth stage. It was found that the corrosion of steel A3 was accelerated by T.f. The morphology of corrosion product of steel A3 immersion in T.f solutions observed through scanning electron microscopy (SEM) transformed from solid globules to tabular plates and to spongy globules and plates.

  5. Preservation of Thiobacillus ferrooxidans and Thiobacillus thiooxidans with activity check.

    Science.gov (United States)

    Gupta, S G; Agate, A D

    1986-01-01

    Cultures of Thiobacillus ferrooxidans and Thiobacillus thiooxidans, used in biohydrometallurgical processes of economic importance, are very difficult to preserve by conventional methods. Hence, to preserve the cultures with their activity intact, various techniques were tried, after determining their respective activity in terms of Iron Oxidation Rate (IOR) and Sulfur Oxidation Rate (SOR). Among the methods tested, along with the recommended method of serial transfer in a liquid medium, were methods such as lyophilization, storage in a liquid nitrogen and mixing with sterile, inert carriers like lignite or chalcopyrite ores. After a period check-up at 4 months and 8 months storage, it was found that out of these methods, mixing with sterile ore followed by storage at 8 degrees C, kept both types of activities intact. The temperature of storage was observed to have a definite effect on activity, in that when the preserved cultures were stored at 8 degrees C, the activity was retained, whereas at 28-30 degrees C (RT) storage, the activity of all the cultures preserved by various techniques, dropped significantly.

  6. Draft genome sequence of the extremely acidophilic biomining bacterium Acidithiobacillus thiooxidans ATCC 19377 provides insights into the evolution of the Acidithiobacillus genus.

    Science.gov (United States)

    Valdes, Jorge; Ossandon, Francisco; Quatrini, Raquel; Dopson, Mark; Holmes, David S

    2011-12-01

    Acidithiobacillus thiooxidans is a mesophilic, extremely acidophilic, chemolithoautotrophic gammaproteobacterium that derives energy from the oxidation of sulfur and inorganic sulfur compounds. Here we present the draft genome sequence of A. thiooxidans ATCC 19377, which has allowed the identification of genes for survival and colonization of extremely acidic environments.

  7. Draft Genome Sequence of the Extremely Acidophilic Biomining Bacterium Acidithiobacillus thiooxidans ATCC 19377 Provides Insights into the Evolution of the Acidithiobacillus Genus

    OpenAIRE

    Valdes, Jorge; Ossandon, Francisco; Quatrini, Raquel; Dopson, Mark; Holmes, David S

    2011-01-01

    Acidithiobacillus thiooxidans is a mesophilic, extremely acidophilic, chemolithoautotrophic gammaproteobacterium that derives energy from the oxidation of sulfur and inorganic sulfur compounds. Here we present the draft genome sequence of A. thiooxidans ATCC 19377, which has allowed the identification of genes for survival and colonization of extremely acidic environments.

  8. Experimental production of indicators for microbial sulfur metabolism in the Chelyabinsk LL5 chondrite: meteorites as standards for biomarker detection on Mars

    Science.gov (United States)

    Tait, A. W.; Wilson, S. A.; Tomkins, A. G.; Gagen, E. J.; Southam, G.

    2016-12-01

    One hurdle to finding evidence for life beyond Earth is being able to identify its chemical, textural and isotopic fingerprints. This is a challenge in environments that can mask biomarker discovery and/or where geochemical and mineralogical limits are still being established. An ideal solution would be to use standards with known chemical and isotopic compositions to reduce/remove any ambiguity of detection. We propose that chondritic meteorites are ideal standards. Chondrites have narrow ranges in mineralogical, chemical and isotopic compositions, including δ34S values. As such, they could preserve biomarkers of theorized sulfur-based metabolisms on Mars. Here, we demonstrate that bacteria can alter the chemistry of chondrites in a detectable and recognisable manner. We exposed polished fragments of the Chelyabinsk LL5 chondrite to an inoculum of the sulfur/iron oxidising bacterium, Acidithiobacillus ferrooxidans. Cell counts and aqueous sulfate concentrations were recorded over the course of a month. Meteorite samples were taken after one, two and four week exposures for FEG-SEM and FIB-SEM imaging, XRD phase analysis, and stable isotope (δ34S) geochemistry. Our electron microscopy work shows that bacteria and associated extracellular polymeric substances coat grains of troilite (FeS) and FeNi alloys. Decreasing aqueous sulfate concentrations, compared to increasing sulfate in abiotic controls, suggests that A. ferrooxidans may have been assimilating the sulfur released by oxidation of troilite. Also, low abundances of secondary minerals that are capable of recording biological fractionation of stable sulfur and/or iron isotopes were also produced: rozenite, gypsum, goethite, lepidocrocite, and jarosite, and may explain the reduction in soluble sulfur. Our FIB-SEM results show that nutrients (e.g., carbon, sulfur and nitrogen) become concentrated in layers at the surfaces of troilite and FeNi alloys within 1 week of incubation. These nutrient-rich regions are

  9. Impact of solvent extraction organics on adsorption and bioleaching of A. ferrooxidans and L. ferriphilum

    Science.gov (United States)

    Hualong, Yu; Xiaorong, Liu

    2017-04-01

    Copper solvent extraction entrained and dissoluted organics (SX organics) in the raffinate during SX operation can contaminated chalcopyrite ores and influence bioleaching efficiency by raffinate recycling. The adsorption and bioleaching of A. ferrooxidans and L. ferriphilum with contaminated ores were investigated. The results showed that, A. ferrooxidans and L. ferriphilum cells could adsorb quickly on minerals, the adsorption rate on contaminated ores were 83% and 60%, respectively, larger than on uncontaminated ores. However, in the bioleaching by the two kinds of acid bacterias, contaminated ores presented a lower bioleaching efficiency.

  10. Biofertilzers with natural phosphate, sulphur and Acidithiobacillus in a siol with low available-P

    Directory of Open Access Journals (Sweden)

    Stamford Newton Pereira

    2003-01-01

    Full Text Available The production of mineral fertilizers is a expensive process, since it requires high energy consumption, and cannot be produced by small farmers. Laboratory assays were conducted to produce P-biofertilizers from natural phosphate (B5, B10, B15, B20, applying sulphur at different rates (5; 10; 15 and 20% inoculated with Acidithiobacillus (S* and testing increasing periods of incubation. A greenhouse experiment was carried out to evaluate the effect of the biofertilizers in a soil with low available P (Typic Fragiudult from the "Zona da Mata" of Pernambuco State, grown with yam bean (Pachyrhizus erosus in two consecutive harvests. The treatments were: Natural Phosphate (NP; biofertilizers produced in laboratory (B5, B10, B15, B20 with sulphur and Acidithiobacillus (NP+S*; natural phosphate with sulphur (20% without Acidithiobacillus (NP+S; triple super phosphate (TSP and a control without phosphorus. Plants were inoculated with a mixture of rhizobia strains (NFB 747 and NFB 748 or did not receive rhizobia inoculation. In bioassays pH and available P in the biofertilizers were analyzed. In the greenhouse experiment shoot dry matter, total N and total P in shoots, soil pH and available P were determined. Higher rates of available P were obtained in biofertilizers with sulphur and Acidithiobacillus (NP+S* and in triple super phosphate (TSP, and biofertilizers with sulphur and Acidithiobacillus (FN+S* and triple super phosphate (TSP increased plant parameters. Native rhizobia were as effective as the strains applied in inoculation. After the two harvests soil presented lower pH values and higher rates of available P when the biofertilizers B15 and B20 with sulphur and Acidithiobacillus were applied.

  11. Metabolism

    Science.gov (United States)

    ... Surgery? Choosing the Right Sport for You Shyness Metabolism KidsHealth > For Teens > Metabolism Print A A A ... food through a process called metabolism. What Is Metabolism? Metabolism (pronounced: meh-TAB-uh-lih-zem) is ...

  12. A kinetic study of the depyritization of oil shale HCl-kerogen concentrate by Thiobacillus ferrooxidans at different temperatures

    Directory of Open Access Journals (Sweden)

    OLGA CVETKOVIC

    2003-05-01

    Full Text Available The results of kinetic studies of bacterial depyritization of HCl-kerogen concentrate of Aleksinac (Serbia oil shale by the chemolithoautotrophic thionic bacteria Thiobacillus ferrooxidans under discontinuous laboratory conditions at various temperatures (0, 20, 28 and 37°C at a pH of ca. 1.5 are presented in this paper. Low pH prevents the occurrence of the precipitation of iron(III-ion hydrolysis products on the substrate particles and thereby reduces the process efficiency. Bacterial depyritization is developed as per kinetics of the first order. The activation energy which points to a successive mechanism of pyrite biooxidation, was computed from the Arrhenius plot. The biochemical kinetics indicators point to a high affinity of the bacteria toward pyrite but small values of Vmax, which are probably the result of decelerated metabolic processes due to the low pH value of the environment resp. the large difference of the pH between the external medium and the cell interior.

  13. Bio-dissolution of spent nickel-cadmium batteries using Thiobacillus ferrooxidans.

    Science.gov (United States)

    Cerruti, C; Curutchet, G; Donati, E

    1998-07-16

    In this study, the production of sulphuric acid in bioreactors with Thiobacillus ferrooxidans attached on elemental sulphur was investigated. These bioreactors reached a maximum H+ productivity of 80 mmol kg-1 d-1 of support. This medium was used for the indirect dissolution of spent nickel-cadmium batteries recovering after 93 days 100% of cadmium, 96.5% of nickel and 95.0% of iron. Moreover, recoveries higher than 90.0% were reached when anodic and cathodic materials were directly added to Thiobacillus ferrooxidans cultures with sulphur as the sole energy source. The results presented show an economic and effective method which could be considered the first step to recycle spent and and discarded batteries preventing one of the many problems of environmental pollution.

  14. 氧化亚铁硫杆菌的分离鉴定及培养条件优化%Isolation and identification of Thiobacillus ferrooxidans and optimization of its culture condition

    Institute of Scientific and Technical Information of China (English)

    庄贺; 沈俊剑; 黎俊; 谢鸿观; 雷泞菲

    2013-01-01

    [Objective] A strain with the ability of bioleaching was isolated.Its culture condition was optimized.[Methods] The strain was isolated from the soil collected from thermoelectric plant in Chengdu,whose taxonomic status was identified based on analysis of morphology characteristics,culture characteristics and 16S rDNA sequence.The optimization experiment was designed with Box-Behnken method in the software Design-Expert,in which the four factors of culture condition that initial pH,temperature,inoculum amount and liquid volume were investigated.Then the results were analyzed with the response surface analysis (RSA) and the optimal culture condition was determined.[Results] The isolated strain was Gram-negative and short-rod,which was named as Z1 and identified as Acidithiobacillus ferrooxidans strain by analysis of its 16S rDNA sequence.The optimal culture condition of the strain was determined,which was initial pH 1.8,optimum temperature 30 ℃,inoculum volume 14% and liquid volume 60 mL medium in a 250 mL flask.Under the optimum condition,the oxidation rate of ferrousion reached at 99.7%.[Conclusion] The strain Z1 was appreciated for bioleaching.%[目的]获得可用于浸矿的菌株,对其培养条件进行优化.[方法]从成都热电厂采集土样中分离得到一株菌株,分析该菌株的形态学特征、培养特征及16S rDNA序列,确定菌株的分类地位.利用Design-Expert软件中的Box-Behnken法设计实验,通过响应面分析对初始pH值、温度、接种量和装液量4个因素进行优化,确定其最适培养条件.[结果]获得菌株Z1,该菌为革兰氏阴性菌,短杆状,经16S rDNA鉴定为嗜酸性氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans,简称At.f).确定菌株最适培养条件为:pH 1.8、温度30℃、接种量14%、装液量250 mL摇瓶装60 mL培养液.在此条件下,Z1的亚铁氧化率可达99.7%.[结论]Z1菌株适合于生物浸矿的应用.

  15. Characterization of a novel thiosulfate dehydrogenase from a marine acidophilic sulfur-oxidizing bacterium, Acidithiobacillus thiooxidans strain SH.

    Science.gov (United States)

    Sharmin, Sultana; Yoshino, Eriko; Kanao, Tadayoshi; Kamimura, Kazuo

    2016-01-01

    A marine acidophilic sulfur-oxidizing bacterium, Acidithiobacillus thiooxidans strain SH, was isolated to develop a bioleaching process for NaCl-containing sulfide minerals. Because the sulfur moiety of sulfide minerals is metabolized to sulfate via thiosulfate as an intermediate, we purified and characterized the thiosulfate dehydrogenase (TSD) from strain SH. The enzyme had an apparent molecular mass of 44 kDa and was purified 71-fold from the solubilized membrane fraction. Tetrathionate was the product of the TSD-oxidized thiosulfate and ferricyanide or ubiquinone was the electron acceptor. Maximum enzyme activity was observed at pH 4.0, 40 °C, and 200 mM NaCl. To our knowledge, this is the first report of NaCl-stimulated TSD activity. TSD was structurally different from the previously reported thiosulfate-oxidizing enzymes. In addition, TSD activity was strongly inhibited by 2-heptyl-4-hydroxy-quinoline N-oxide, suggesting that the TSD is a novel thiosulfate:quinone reductase.

  16. PROGRESS OF THE STUDIES ON GENE TRANSFER SYSTEM OF THIOBACILLUS FERROOXIDANS%氧化亚铁硫杆菌基因转移系统研究进展

    Institute of Scientific and Technical Information of China (English)

    林建群; 彭基斌; 颜望明

    2001-01-01

    Thiobacillus ferrooxidans is a extremely acidophilic and obligately chemlithotrophic bacterium. It is the most important work for gene engineering of T.ferrooxidans to develop an efficient gene transfer systems. This paper summarized the genetics background of T.ferrooxidans, the process of establishing such a kind of gene transfer system, and its application in constructing arsenic resistance genetically engineered bacteria. Ref 22

  17. Dominance of Acidithiobacillus at ore surface of Zijinshan commercial low-grade copper bioleaching heap

    Institute of Scientific and Technical Information of China (English)

    LIU Xing-yu; CHEN Bo-wei; WEN Jian-kang

    2008-01-01

    The microbial community structure in the ore surface of Zijinshan commercial low-grade copper bioleaching heap was investigated by 16S rRNA gene clone library.For both bacteria and Archaea,105 clones were sequenced.The dominant bacteria species present in the ore surface were Acidithiobacillus and Leptospirillum,accounting for 51.42% and 48.57%,respectively.However,for the Archaea,only one operational taxonomic unit (OUT) belonged to Ferroplasma acidiphilum.These results indicate that function of genus Acidithiobacillus in the commercial low-grade copper bioleaching heap may be underestimated.More detailed and quantitative information on microbial community structure over time are now under investigation.

  18. Detection, identification and typing of Acidithiobacillus species and strains: a review.

    Science.gov (United States)

    Nuñez, Harold; Covarrubias, Paulo C; Moya-Beltrán, Ana; Issotta, Francisco; Atavales, Joaquín; Acuña, Lillian G; Johnson, D Barrie; Quatrini, Raquel

    2016-09-01

    The genus Acidithiobacillus comprises several species of Gram-negative acidophilic bacteria that thrive in natural and man-made low pH environments in a variety of geo-climatic contexts. Beyond their fundamental interest as model extreme acidophiles, these bacteria are involved in the processing of minerals and the desulfurization of coal and natural gas, and are also sources of environmental pollution due to their generation of acid mine drainage and corrosion of cement and concrete structures. Acidithiobacillus spp. are therefore considered a biotechnologically relevant group of bacteria, and their identification and screening in natural and industrial environments is of great concern. Several molecular typing methodologies have been instrumental in improving knowledge of the inherent diversity of acidithiobacilli by providing information on the genetic subtypes sampled in public and private culture collections; more recently, they have provided specific insight into the diversity of acidithiobacilli present in industrial and natural environments. The aim of this review is to provide an overview of techniques used in molecular detection, identification and typing of Acidithiobacillus spp. These methods will be discussed in the context of their contribution to the general and specific understanding of the role of the acidithiobacilli in microbial ecology and industrial biotechnology. Emerging opportunities for industrial and environmental surveillance of acidithiobacilli using next-generation molecular typing methodologies are also reviewed.

  19. Microbial community succession mechanism coupling with adaptive evolution of adsorption performance in chalcopyrite bioleaching.

    Science.gov (United States)

    Feng, Shoushuai; Yang, Hailin; Wang, Wu

    2015-09-01

    The community succession mechanism of Acidithiobacillus sp. coupling with adaptive evolution of adsorption performance were systematically investigated. Specifically, the μmax of attached and free cells was increased and peak time was moved ahead, indicating both cell growth of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans was promoted. In the mixed strains system, the domination courses of A. thiooxidans was dramatically shortened from 22th day to 15th day, although community structure finally approached to the normal system. Compared to A. ferrooxidans, more positive effects of adaptive evolution on cell growth of A. thiooxidans were shown in either single or mixed strains system. Moreover, higher concentrations of sulfate and ferric ions indicated that both sulfur and iron metabolism was enhanced, especially of A. thiooxidans. Consistently, copper ion production was improved from 65.5 to 88.5 mg/L. This new adaptive evolution and community succession mechanism may be useful for guiding similar bioleaching processes.

  20. Occurrences at mineral-bacteria interface during oxidation of arsenopyrite by Thiobacillus ferrooxidans

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, M.G.M. [Univ. Autonoma de San Luis Potosi (Mexico). Inst. de Metalurgia; Mustin, C.; Berthelin, J. [Univ. Henri Poincare, Vandoeuvre-les-Nancy (France). Centre de Pedologie Biologique; Donato, P. de; Barres, O.; Marion, P. [I.N.P.L.-E.N.S.G., Vandoeuvre-les-Nancy (France)

    1995-04-05

    The combination of an improved bacterial desorption method, scanning electron microscopy (SEM), diffuse reflectance and transmission infrared Fourier transform spectroscopy, and a desorption-leaching device like high-pressure liquid chromatography (HPLC) was used to analyze bacterial populations and surface-oxidized phases during the arsenopyrite biooxidation by Thiobacillus ferrooxidans. The bacterial distribution, the physicochemical composition of the leachate, the evolution of corrosion patterns, and the nature and amount of the surface-oxidized chemical species characterized different behavior for each step of arsenopyrite bioleaching.

  1. Metabolism

    Science.gov (United States)

    ... Are More Common in People With Type 1 Diabetes Metabolic Syndrome Your Child's Weight Healthy Eating Endocrine System Blood Test: Basic Metabolic Panel (BMP) Activity: Endocrine System Growth Disorders Diabetes Center Thyroid Disorders Your Endocrine System Movie: Endocrine ...

  2. Metabolism

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    2008255 Serum adiponectin level declines in the elderly with metabolic syndrome.WU Xiaoyan(吴晓琰),et al.Dept Geriatr,Huashan Hosp,Fudan UnivShanghai200040.Chin J Geriatr2008;27(3):164-167.Objective To investigate the correlation between ser-um adiponectin level and metabolic syndrome in the elderly·Methods Sixty-one subjects with metabolic syndrome and140age matched subjects without metabolic

  3. Draft Genome Sequence of a Novel Acidophilic Iron-Oxidizing Firmicutes Species, "Acidibacillus ferrooxidans" (SLC66T).

    Science.gov (United States)

    Ñancucheo, Ivan; Oliveira, Renato; Dall'Agnol, Hivana; Johnson, D Barrie; Grail, Barry; Holanda, Roseanne; Nunes, Gisele Lopes; Cuadros-Orellana, Sara; Oliveira, Guilherme

    2016-05-19

    Here, we present the draft genome sequence of the type strain of "Acidibacillus ferrooxidans," a mesophilic, heterotrophic, and acidophilic bacterium that was isolated from mine spoilage subjected to accelerated weathering in humidity cell tests carried out by the former U.S. Bureau of Mines in Salt Lake City, UT.

  4. Draft Genome Sequence of the Extremophile Acidithiobacillus thiooxidans A01, Isolated from the Wastewater of a Coal Dump.

    Science.gov (United States)

    Yin, Huaqun; Zhang, Xian; Liang, Yili; Xiao, Yunhua; Niu, Jiaojiao; Liu, Xueduan

    2014-04-03

    The draft genome of Acidithiobacillus thiooxidans A01 contains 3,820,158 bp, with a G+C content of 53.08% and 3,660 predicted coding sequences (CDSs). The bacterium contains a series of specific genes involved in the oxidation of elemental sulfur and reduced inorganic sulfur compounds (RISCs).

  5. Bacterial CS2 Hydrolases from Acidithiobacillus thiooxidans Strains Are Homologous to the Archaeal Catenane CS2 Hydrolase

    NARCIS (Netherlands)

    Smeulders, M.J.; Pol, A. van der; Venselaar, H.; Barends, T.R.; Hermans, J.; Jetten, M.S.M.; Camp, H.J.M. op den

    2013-01-01

    Carbon disulfide (CS2) and carbonyl sulfide (COS) are important in the global sulfur cycle, and CS2 is used as a solvent in the viscose industry. These compounds can be converted by sulfur-oxidizing bacteria, such as Acidithiobacillus thiooxidans species, to carbon dioxide (CO2) and hydrogen sulfide

  6. Comparison and evaluation of immobilization methods for preparing bacterial probes using acidophilic bioleaching bacteria Acidithiobacillus thiooxidans for AFM studies.

    Science.gov (United States)

    Diao, Mengxue; Taran, Elena; Mahler, Stephen M; Nguyen, Anh V

    2014-07-01

    We evaluated different strategies for constructing bacterial probes for atomic force microscopy studies of bioleaching Acidithiobacillus thiooxidans interacting with pyrite mineral surfaces. Of three available techniques, the bacterial colloidal probe technique is the most reliable and provides a versatile platform for quantifying true interactive forces between bioleaching microorganisms and mineral surfaces.

  7. Metabolism

    Science.gov (United States)

    ... a particular food provides to the body. A chocolate bar has more calories than an apple, so ... acid phenylalanine, needed for normal growth and protein production). Inborn errors of metabolism can sometimes lead to ...

  8. Leptosririllum ferrooxidans-sulfide mineral interactions with reference to bioflotation nad bioflocculation

    Institute of Scientific and Technical Information of China (English)

    A.VILINSKA; K.HANUMANTHA RAO

    2008-01-01

    The adhesion of ferrous ions grown Leptospirillum ferrooxidans cells on pyrite and chalcopyrite minerals was investigated through adsorption,Zeta-potential and diffuse reflectance FT-IR measurements.The influence of bacterial species on minerals floatability was determined by Hallimond flotation tests while the flocculation behaviour was examined by Turbiscan measurements.The minerals iso-electric point (pH 6.5-7.5) after interaction with bacterial cells shifted towards cells iso-electric point (pH 3.3),indicating the chemical nature of cells adsorption on mineral surfaces.The FT-IR spectra of minerals treated with bacterial cells showed the presence of all the cell functional groups signifying cells adsorption.The bacterial cells adsorption on chalcopyrite was higher compared with pyrite,which agreed with cells greater depression effect on chalcopyrite flotation and pronounced flocculation behaviour in comparison with pyrite.

  9. Electro-generative mechanism for simultaneous leaching of pyrite and MnO2 in presence of A. ferrooxidans

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A dual cell system was used to study the output power, output voltage, galvanic polarization of anode and cathode, and the relationship between the electric quantity(Q) and some factors, such as the dissolved Fe2+ magnitude, the time in the electrogenerative simultaneous leaching with bacteria(BEGSL) and without bacteria(EGSL). A three-electrode system was adopted to study their individual self-corrosion current, which was smaller compared with the galvanic current. The results show that the output power and voltage in BEGSL are higher than those in EGSL. The accumulated sulfur on the surface of sulfides produced in BEGSL can be oxidized by A. ferrooxidans, and the ratio of biologic electric quantity reaches 51.50% in 72 h. The first stage both in EGSL and in BEGSL is the dissolution of pyrite on the surface to ferrous ion and sulfur element, which was oxidized by A. ferrooxidans in the further procedure.

  10. Submicro-battery effect and selective bio-oxidation model of gold-bearing arsenopyrite by Thiobacillus ferrooxidans

    Institute of Scientific and Technical Information of China (English)

    杨洪英; 杨立; 赵玉山; 陈刚; 吕久吉; 范有静

    2002-01-01

    Through the study by electronic probe it was found that many new cracks and holes appear on the surface of gold-bearing arsenopyrite crystal oxidized by Thiobacillus ferrooxidans, which are along with some directions. Then the selective bio-oxidation model of gold-bearing arsenopyrite was set up. The selective bio-oxidation resulting from the submicro-battery effect of gold/ arsenopyrite mineral pairs naturally forms in the gold-bearing arsenopyrite crystal. Thiobacillus ferrooxidans has priority to oxidize the place of gold-rich and oxidizes selectedly along with the crystal border, crystal face and crack. The bacteria oxidation process of gold-bearing arsenopyrite is divided into three stages: the first stage is the surface oxidation, the second stage is restraining oxidation and the third stage is the filament oxidation, bacteria oxidize along with cracks of arsenopyrite.

  11. Comparative study on effects of Tween-80 and sodium isobutyl-xanthate on growth and sulfur-oxidizing activities of Acidithiobacillus albertensis BY-05

    Institute of Scientific and Technical Information of China (English)

    ZHANG Cheng-gui; XIA Jin-lan; ZHANG Rui-yong; PENG An-an; NIE Zhen-yuan; QIU Guan-zhou

    2008-01-01

    Effects of two typical surfactants, Tween-80 and sodium isobutyl-xanthate (NaIBX), with different concentrations on the growth and sulfur-oxidizing activities of a new strain Acidithiobacillus albertensis BY-05, an acidophilic sulfur-oxidizing bacterium, were investigated. The results indicate that both surfactants can enhance the growth and sulfur-oxidizing activities of A. albertensis BY-05 only at some special concentrations, e.g., 10-4-10-8 g/L for NaIBX and lower than 10-8 g/L for Tween-80, but were inhibited and even harmful at higher concentrations. Both surfactants can not be metabolized by A. albertensis BY-05. The contact between the bacteria and the sulfur particles may be dependent upon both the extracellular substance and the surfactants, both of which provide the amphiphilic environment improving the attachment for bacteria to the sulfur particles surface. These data could be significant for enlarging the applications of both A. albertensis BY-05 and some typical surfactants for industrial bioleaching of sulfides minerals.

  12. Effects of inhibitors and NaCl on the oxidation of reduced inorganic sulfur compounds by a marine acidophilic, sulfur-oxidizing bacterium, Acidithiobacillus thiooxidans strain SH.

    Science.gov (United States)

    Kamimura, Kazuo; Higashino, Emi; Kanao, Tadayoshi; Sugio, Tsuyoshi

    2005-02-01

    The effect of NaCl and the pathways of the oxidation of reduced inorganic sulfur compounds were studied using resting cells and cell-free extracts of Acidithiobacillus thiooxidans strain SH. This isolate specifically requires NaCl for growth. The oxidation of sulfur and sulfite by resting cells was strongly inhibited by 2-heptyl-4-hydroxyquinoline-N-oxide. Carbonylcyanide m-chlorophenyl-hydrazone and monensin were also relatively strong inhibitors. Thiosulfate-oxidizing activity was not inhibited by these uncouplers. Valinomycin did not inhibit the oxidation of sulfur compounds. NaCl stimulated the sulfur- and sulfite-oxidizing activities in resting cells but not in cell-free extracts. The tetrathionate-oxidizing activity in resting cells was slightly stimulated by NaCl, whereas it did not influence the thiosulfate-oxidizing activity. Sulfide oxidation was biphasic, suggesting the formation of intermediate sulfur. The initial phase of sulfide oxidation was not affected by NaCl, whereas the subsequent oxidation of sulfur in the second phase was Na+-dependent. A model is proposed for the role of NaCl in the metabolism of reduced sulfur compounds in A. thiooxidans strain SH.

  13. Enhanced Cr bioleaching efficiency from tannery sludge with coinoculation of Acidithiobacillus thiooxidans TS6 and Brettanomyces B65 in an air-lift reactor.

    Science.gov (United States)

    Fang, Di; Zhou, Li-Xiang

    2007-09-01

    Bioleaching process has been demonstrated to be an effective technology in removing Cr from tannery sludge, but a large quantity of dissolved organic matter (DOM) present in tannery sludge often exhibits a marked toxicity to chemolithoautotrophic bioleaching bacteria such as Acidithiobacillus thiooxidans. The purpose of the present study was therefore to enhance Cr bioleaching efficiencies through introducing sludge DOM-degrading heterotrophic microorganism into the sulfur-based sludge bioleaching system. An acid-tolerant DOM-degrading yeast strain Brettanomyces B65 was successfully isolated from a local Haining tannery sludge and it could metabolize sludge DOM as a source of energy and carbon for growth. A combined bioleaching experiment (coupling Brettanomyces B65 and A. thiooxidans TS6) performed in an air-lift reactor indicated that the rates of sludge pH reduction and ORP increase were greatly improved, resulting in enhanced Cr solubilization. Compared with the 5 days required for maximum solubilization of Cr for the control (single bioleaching process without inoculation of Brettanomyces B65), the bioleaching period was significantly shorten to 3 days for the combined bioleaching system. Moreover, little nitrogen and phosphorous were lost and the content of Cr was below the permitted levels for land application after 3 days of bioleaching treatment.

  14. Hydrogen sulfide removal from air by Acidithiobacillus thiooxidans in a trickle bed reactor.

    Science.gov (United States)

    Ramirez, M; Gómez, J M; Cantero, D; Páca, J; Halecký, M; Kozliak, E I; Sobotka, M

    2009-09-01

    A strain of Acidithiobacillus thiooxidans immobilized in polyurethane foam was utilized for H(2)S removal in a bench-scale trickle-bed reactor, testing the limits of acidity and SO(4) (2-) accumulation. The use of this acidophilic strain resulted in remarkable stability in the performance of the system. The reactor maintained a >98-99 % H(2)S removal efficiency for c of up to 66 ppmv and empty bed residence time 98 % H(2)S was achieved under steady-state conditions, over the pH range of 0.44-7.30. Despite the accumulation of acidity and SO(4) (2-) (up to 97 g/L), the system operated without inhibition.

  15. Purification and properties of thiosulfate dehydrogenase from Acidithiobacillus thiooxidans JCM7814.

    Science.gov (United States)

    Nakamura, K; Nakamura, M; Yoshikawa, H; Amano, Y

    2001-01-01

    A key enzyme of the thiosulfate oxidation pathway in Acidithiobacillus thiooxidans JCM7814 was investigated. As a result of assaying the enzymatic activities of thiosulfate dehydrogenase, rhodanese, and thiosulfate reductase at 5.5 of intracellular pH, the activity of thiosulfate dehydrogenase was measured as the key enzyme. The thiosulfate dehydrogenase of A. thiooxidans JCM7814 was purified using three chromatographies. The purified sample was electrophoretically homogeneous. The molecular mass of the enzyme was 27.9 kDa and it was a monomer. This enzyme had cytochrome c. The optimum pH and temperature of this enzyme were 3.5 and 35 degrees C. The enzyme was stable in the pH range from 5 to 7, and it was stable up to 45 degrees C. The isoelectric point of the enzyme was 8.9. This enzyme reacted with thiosulfate as a substrate. The Km was 0.81 mM.

  16. Biochemical and molecular characterization of the NAD(+)-dependent isocitrate dehydrogenase from the chemolithotroph Acidithiobacillus thiooxidans.

    Science.gov (United States)

    Inoue, Hiroyuki; Tamura, Takashi; Ehara, Nagisa; Nishito, Akira; Nakayama, Yumi; Maekawa, Makiko; Imada, Katsumi; Tanaka, Hidehiko; Inagaki, Kenji

    2002-08-27

    An isocitrate dehydrogenase (ICDH) with an unique coenzyme specificity from Acidithiobacillus thiooxidans was purified and characterized, and its gene was cloned. The native enzyme was homodimeric with a subunit of M(r) 45000 and showed a 78-fold preference for NAD(+) over NADP(+). The cloned ICDH gene (icd) was expressed in an icd-deficient strain of Escherichia coli EB106; the activity was found in the cell extract. The gene encodes a 429-amino acid polypeptide and is located between open reading frames encoding a putative aconitase gene (upstream of icd) and a putative succinyl-CoA synthase beta-subunit gene (downstream of icd). A. thiooxidans ICDH showed high sequence similarity to bacterial NADP(+)-dependent ICDH rather than eukaryotic NAD(+)-dependent ICDH, but the NAD(+)-preference of the enzyme was suggested due to residues conserved in the coenzyme binding site of the NAD(+)-dependent decarboxylating dehydrogenase.

  17. [Expression of phosphofructokinase gene from Escherichia coli K-12 in obligately autotrophic bacterium Acidithiobacillus thiooxidans].

    Science.gov (United States)

    Tian, Keli; Lin, Jianqun; Liu, Xiangmei; Liu, Ying; Zhang, Changkai

    2003-10-01

    A plasmid pSDK-1 containing the Escherichia coli phosphofructokinase-1 (EC 2.7.1. 11) gene (pfkA) was constructed and transferred into Acidithiobacillus thiooxidans Tt-Z2 by conjugation. The transfer frequency of plasmid from E. coli to Tt-Z2 was 2.6 x 10(-6). More than 68% of Tt-Z2 cells carried the recombinant plasmids after being cultured for 50 generations without selective pressure, which showed that pSDK-1 was maintained consistently in Tt-Z2. The pfkA gene from E. coli could be expressed in this obligately autotrophic bacterium but the enzyme activity (14 U/g was lower than that in E. coli (K-12: 86 U/g; DF1010 carrying plasmid pSDK-1: 97 U/g). In th presence of glucose, the Tt-Z2 transconjugant consumed glucose leading to a better growth yield.

  18. METABOLISM

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Objective: To determine the allele frequencies of genetic variants 373 Ala→Pro and 451 Arg→Gln of cholesteryl ester transfer protein (CETP) and to explore their potential impacts on serum lipid metabolism. Methods: The genotypes in CETP codon 373 and 451 in 91 German healthy students and 409 an-

  19. Potentiality of Acidithiobacillus thiooxidans in Microbial Solubilization of Phosphate Mine Tailings

    Directory of Open Access Journals (Sweden)

    S Dhakar

    2015-04-01

    Full Text Available This paper deals with the solubilization behavior of the tailings produced by the floatation of a complex low grade phosphate ore. The composition of the tailings was essentially dolomite (52.04% with minor amounts of phosphate, iron and aluminium oxides (10.4 and 0.5% respectively. The presence of these products created uncontrolled land pollution and severely affected groundwater. An initiative has been taken up for utilization of this waste to generate an eco-friendly product. First step towards this panorama is incorporation of suitable microorganisms for the biodegradation of this effluent. Sulphur oxidizing bacteria Acidithiobacillus thiooxidans produces sulphuric acid which neutralizes the dolomitic tailings and convert it into plant available forms. The solubilization activity was tested in sulphur medium with 5, 10, 15 and 20% concentration of tailings. The solubilization is graded on the basis of pH, Electrical conductivity (EC, soluble calcium and magnesium and soluble phosphate. The results from ex-situ experiments showed that the treatment with 15% tailings ended with highest solubilization. The values of pH, EC, soluble calcium and magnesium and soluble phosphate for this treatment were 4.92, 31.6 dS/m, 10.8 mL EDTA and 17.24 µg/mL respectively. Also, the results proved that sulphur oxidizing bacteria Acidithiobacillus thiooxidans is capable of solubilizing dolomitic tailings from the Jhamarkotra mines. Finally, an important factor taken into account was solubilization of residual phosphate along with dolomite in the tailings. This combined action affects the solubilization behaviour of the residue, which was also showed successfully with the assayed laboratory studies.

  20. The inhibitory effect of antimicrobial zeolite on the biofilm of Acidithiobacillus thiooxidans.

    Science.gov (United States)

    Haile, Tesfaalem; Nakhla, George

    2010-02-01

    The inhibitory effect of antimicrobial zeolite coated concrete specimens (Z2) against Acidithiobacillus thiooxidans was studied by measuring biomass dry cell weight (DCW), biological sulphate generation, and oxygen uptake rates (OURs). Uncoated (UC), and blank zeolite coated without antimicrobial agent (ZC) concrete specimens were used as controls. The study was undertaken by exposing inoculated basal nutrient medium (BNM) to the various specimens. The coating material was prepared by mixing zeolite, epoxy and cure with ratios, by weight of 2:2:1. Concrete specimens were characterized before and after exposure to inoculated or sterile BNM by field emission-scanning electron microscopy (FE-SEM). Gypsum, which was absent in the other test concrete specimens, was detected in uncoated specimens exposed to the bacterium. In UC and ZC, the growth of the bacteria increased throughout the duration of the experiment. However, significant biomass inhibition was observed in experiments where Z2 was used. The overall biomass growth rate in suspension before the specimens were placed ranged from 3.18 to 3.5 mg DCW day(-1). After the bacterium was exposed to UC and ZC, growth continued with a corresponding value of 4 + or - 0.4 and 5.5 + or - 0.6 mg DCW day(-1), respectively. No biomass growth was observed upon exposure of the bacterium to Z2. Similarly, while biological sulphur oxidation rates in UC and ZC were 88 + or - 13 and 238 + or - 25 mg SO(4)(2-) day(-1), respectively, no sulphate production was observed in experiments where Z2 concrete specimens were used. Peak OURs for UC and ZC ranged from 2.6 to 5.2 mg l(-1) h(-1), and there was no oxygen uptake in those experiments where Z2 was used. The present study revealed that the antimicrobial zeolite inhibits the growth of both planktonic as well as biofilm populations of Acidithiobacillus thiooxidans.

  1. Diversity and Ecophysiology of New Isolates of Extremely Acidophilic CS2-Converting Acidithiobacillus Strains

    Science.gov (United States)

    Smeulders, Marjan J.; Pol, Arjan; Zandvoort, Marcel H.; Jetten, Mike S. M.

    2013-01-01

    Biofiltration of industrial carbon disulfide (CS2)-contaminated waste air streams results in the acidification of biofilters and therefore reduced performance, high water use, and increased costs. To address these issues, we isolated 16 extremely acidophilic CS2-converting Acidithiobacillus thiooxidans strains that tolerated up to 6% (vol/vol) sulfuric acid. The ecophysiological properties of five selected strains (2Bp, Sts 4-3, S1p, G8, and BBW1) were compared. These five strains had pH optima between 1 (2Bp) and 2 (S1p). Their affinities for CS2 ranged between 80 (G8) and 130 (2Bp) μM. Strains S1p, G8, and BBW1 had more hydrophobic cell surfaces and produced less extracellular polymeric substance than did strains 2Bp and Sts 4-3. All five strains converted about 80% of the S added as CS2 to S0 when CS2 was supplied in excess. The rate of S0 consumption varied between 7 (Sts 4-3) and 63 (S1p) nmol O2 min−1 ml culture−1. Low S0 consumption rates correlated partly with low levels of cell attachment to externally produced S0 globules. During chemostat growth, the relative amount of CS2 hydrolase in the cell increased with decreasing growth rates. This resulted in more S0 accumulation during CS2 overloads at low growth rates. Intermittent interruptions of the CS2 supply affected all five strains. Strains S1p, G8, and BBW1 recovered from 24 h of starvation within 4 h, and strains 2Bp and Sts 4-3 recovered within 24 h after CS2 was resupplied. We recommend the use of mixtures of Acidithiobacillus strains in industrial biofilters. PMID:23995926

  2. Gene function analysis in environmental isolates: The nif regulon of the strict iron oxidizing bacterium Leptospirillum ferrooxidans

    Science.gov (United States)

    Parro, Víctor; Moreno-Paz, Mercedes

    2003-01-01

    A random genomic library from an environmental isolate of the Gram-negative bacterium Leptospirillum ferrooxidans has been printed on a microarray. Gene expression analysis was carried out with total RNA extracted from L. ferrooxidans cultures in the presence or absence of ammonium as nitrogen source under aerobic conditions. Although practically nothing is known about the genome sequence of this bacterium, this approach allowed us the selection and sequencing of only those clones bearing genes that showed an altered expression pattern. By sequence comparison, we have identified most of the genes of nitrogen fixation regulon in L. ferrooxidans, like the nifHDKENX operon, encoding the structural components of Mo-Fe nitrogenase; nifSU-hesB-hscBA-fdx operon, for Fe-S cluster assembly; the amtB gene (ammonium transporter); modA (molybdenum ABC type transporter); some regulatory genes like ntrC, nifA (the specific activator of nif genes); or two glnB-like genes (encoding the PII regulatory protein). Our results show that shotgun DNA microarrays are very powerful tools to accomplish gene expression studies with environmental bacteria whose genome sequence is still unknown, avoiding the time and effort necessary for whole genome sequencing projects. PMID:12808145

  3. Efeito da adição de nanopartículas na biolixiviação da calcopirita ('CU''FE''S IND.2') por Acidithiobacillus ferrooxidans LR

    OpenAIRE

    Silva, Daniel Rodrigues da [UNESP

    2011-01-01

    A biolixiviação (lixiviação bacteriana) é uma alternativa para a extração de metais presentes em sulfetos minerais empregando microorganismos. Dentre as principais vantagens da biohidrometalurgia em relação aos métodos convencionais podem ser destacadas a não-emissão de SO2 para a atmosfera, pequeno gasto com insumos, pois são produzidos pelos próprios microorganismos, baixa demanda energética e o tratamento de minérios contendo metais em baixo teor. Uma das espécies envolvidas na biolixiviaç...

  4. Sulfur-oxidation Related doxDA Operons in Acidithiobacillus ferrooxidans%与硫氧化相关的嗜酸硫氧化亚铁硫杆菌doxDA操纵元的分析

    Institute of Scientific and Technical Information of China (English)

    金城

    2008-01-01

    用传统的选冶工艺很难对低品位及伴生硫化矿进行有效的提取,而硫化矿生物浸出技术特别适用于处理这类矿物资源;相对于传统选冶工艺,它具有流程短、能耗小、成本低、污染少等优点,具有广阔的工业应用前景。

  5. The Two-component System RsrS-RsrR Regulates the Tetrathionate Intermediate Pathway for Thiosulfate Oxidation in Acidithiobacillus caldus

    Directory of Open Access Journals (Sweden)

    Zhaobao Wang

    2016-11-01

    Full Text Available Acidithiobacillus caldus (A. caldus is a common bioleaching bacterium that possesses a sophisticated and highly efficient inorganic sulfur compound metabolism network. Thiosulfate, a central intermediate in the sulfur metabolism network of A. caldus and other sulfur-oxidizing microorganisms, can be metabolized via the tetrathionate intermediate (S4I pathway catalyzed by thiosulfate:quinol oxidoreductase (Tqo or DoxDA and tetrathionate hydrolase (TetH. In A. caldus, there is an additional two-component system called RsrS-RsrR. Since rsrS and rsrR are arranged as an operon with doxDA and tetH in the genome, we suggest that the regulation of the S4I pathway may occur via the RsrS-RsrR system. To examine the regulatory role of the two-component system RsrS-RsrR on the S4I pathway, ΔrsrR and ΔrsrS strains were constructed in A. caldus using a newly developed markerless gene knockout method. Transcriptional analysis of the tetH cluster in the wild type and mutant strains revealed positive regulation of the S4I pathway by the RsrS-RsrR system. A 19bp inverted repeat sequence (IRS, AACACCTGTTACACCTGTT located upstream of the tetH promoter was identified as the binding site for RsrR by using electrophoretic mobility shift assays (EMSAs in vitro and promoter-probe vectors in vivo. In addition, ΔrsrR and ΔrsrS strains cultivated in K2S4O6- medium exhibited significant growth differences when compared with the wild type. Transcriptional analysis indicated that the absence of rsrS or rsrR had different effects on the expression of genes involved in sulfur metabolism and signaling systems. Finally, a model of tetrathionate sensing by RsrS, signal transduction via RsrR, and transcriptional activation of tetH-doxDA was proposed to provide insights towards the understanding of sulfur metabolism in A. caldus. This study also provided a powerful genetic tool for studies in A. caldus.

  6. Bioleaching of ultramafic tailings by acidithiobacillus spp. for CO2 sequestration.

    Science.gov (United States)

    Power, Ian M; Dipple, Gregory M; Southam, Gordon

    2010-01-01

    Bioleaching experiments using various acid-generating substances, i.e., metal sulfides and elemental sulfur, were conducted to demonstrate the accelerated dissolution of chrysotile tailings collected from an asbestos mine near Clinton Creek, Yukon, Canada. Columns, possessing an acid-generating substance colonized with Acidithiobacillus sp., produced leachates with magnesium concentrations that were an order of magnitude greater than mine site waters or control column leachates. In addition, chrysotile tailings were efficient at neutralizing acidity, which resulted in the immobilization of metals (Fe, Cu, Zn) associated with the metal sulfide mine tailings that were used to generate acid. This suggests that tailings from acid mine drainage environments may be utilized to enhance chrysotile dissolution without polluting "downstream" ecosystems. These results demonstrate that the addition of an acid-generating substance in conjunction with a microbial catalyst can significantly enhance the release of magnesium ions, which are then available for the precipitation of carbonate minerals. This process, as part of a carbon dioxide sequestration program, has implications for reducing net greenhouse gas emissions in the mining industry.

  7. Inhibition of microbial concrete corrosion by Acidithiobacillus thiooxidans with functionalised zeolite-A coating.

    Science.gov (United States)

    Haile, Tesfaalem; Nakhla, George

    2009-01-01

    The inhibition of the corrosive action of Acidithiobacillus thiooxidans on concrete specimens coated by functionalised zeolite-A containing 14% zinc and 5% silver by weight was studied. Uncoated concrete specimens, epoxy-coated concrete specimens (EP), and functionalised zeolite-A coated concrete specimens with epoxy to zeolite weight ratios of 3:1 (Z1), 2:2 (Z2) and 1:3 (Z3) were studied. Specimens were characterised by x-ray powder diffraction and field emission scanning electron microscopy for the identification of corrosion products and morphological changes. Biomass growth at the conclusion of the 32-day experiments was 4, 179 and 193 mg volatile suspended solids g(-1) sulphur for the uncoated, EP and Z1 specimens, whereas that of Z2 and Z3 were negligible. In the uncoated, EP and Z1 specimens, sulphate production rates were 0.83, 9.1 and 8.8 mM SO(4)(2-) day(-1) and the specific growth rates, mu, were 0.14, 0.57 and 0.47 day(-1), respectively. The corresponding values for Z2 and Z3 were negligible due to their bacterial inhibition characteristics.

  8. Occurrence and fluctuations of Acidithiobacillus ssp. in uranium mine effluents, Caldas, MG

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Michelle Burato de; Roque, Claudio Vitor; Gomes, Heliana de Azevedo [Brazilian Nuclear Energy Commission (CNEN-MG), Pocos de Caldas, MG (Brazil)]. E-mail: michelle_borato@hotmail.com; cvroque@cnen.gov.br; hgomes@cnen.gov.br

    2007-07-01

    Sulphide ores that are present in mining areas can cause serious environmental problems because of the action of chemolithotrophic bacteria of the Acidithiobacillus genera, mainly A. ferroxidans and A. thiooxidans. These microorganisms are capable of oxidizing sulphide minerals, elemental sulphur and ferrous ion, possibly mobilizing radionuclides such as uranium into the environment. In this context, the present study was undertaken in order to determine the occurrence and fluctuations of populations of A. ferroxidans and A. thiooxidans in effluents from an uranium mine, part of the Ore Treatment Unit (UTM) in Caldas, MG - Brazil, analyzing samples from 9 sampling points (CM, BS, D3, 25, 27, 32, 41, 75, and 76). The results showed that the population of A. thiooxidans occurs more often (44.4%) than the population of A. ferroxidans (31.5%). In the sample points within the UTM-environment interface, points 25 and 76 were considered the most susceptible to acid mine drainage and activity of bacteria involved in metal bioleaching. The seasonal behavior of some of the variables observed at points CM, D3, and BS, when evaluated simultaneously, such as high Eh values, low pH values, the detection of greater percentages of incidence and higher counts of A. ferroxidans and A. thiooxidans, showed that these points are the main locations for the occurrence of acid mine drainage and bacterial bioleaching in the UTM and should be considered as critical points for a possible decommissioning action. (author)

  9. A new genome of Acidithiobacillus thiooxidans provides insights into adaptation to a bioleaching environment.

    Science.gov (United States)

    Travisany, Dante; Cortés, María Paz; Latorre, Mauricio; Di Genova, Alex; Budinich, Marko; Bobadilla-Fazzini, Roberto A; Parada, Pilar; González, Mauricio; Maass, Alejandro

    2014-11-01

    Acidithiobacillus thiooxidans is a sulfur oxidizing acidophilic bacterium found in many sulfur-rich environments. It is particularly interesting due to its role in bioleaching of sulphide minerals. In this work, we report the genome sequence of At. thiooxidans Licanantay, the first strain from a copper mine to be sequenced and currently used in bioleaching industrial processes. Through comparative genomic analysis with two other At. thiooxidans non-metal mining strains (ATCC 19377 and A01) we determined that these strains share a large core genome of 2109 coding sequences and a high average nucleotide identity over 98%. Nevertheless, the presence of 841 strain-specific genes (absent in other At. thiooxidans strains) suggests a particular adaptation of Licanantay to its specific biomining environment. Among this group, we highlight genes encoding for proteins involved in heavy metal tolerance, mineral cell attachment and cysteine biosynthesis. Several of these genes were located near genetic motility genes (e.g. transposases and integrases) in genomic regions of over 10 kbp absent in the other strains, suggesting the presence of genomic islands in the Licanantay genome probably produced by horizontal gene transfer in mining environments.

  10. Fractionation behavior of heavy metals in soil during bioleaching with Acidithiobacillus thiooxidans.

    Science.gov (United States)

    Naresh Kumar, R; Nagendran, R

    2009-09-30

    The effects of bioleaching on the fractionation of soil heavy metals were investigated in this study. Bioleaching of heavy metals from contaminated soil was carried out in shake flask experiments. Acidophilic sulfur oxidizing bacteria Acidithiobacillus thiooxidans isolated from soil was used for bioleaching. Bioleaching resulted in removal of heavy metals at higher levels. Variations in the binding forms of heavy metals before, during and after bioleaching were evaluated. It was noticed that bioleaching affected the binding forms of all the heavy metals present in the soil. The major contaminant chromium bound mainly to the fractions of soil which are not very reactive (organic and residual fractions) also showed good removal efficiency. Bioleaching influenced the fractionation of metals in soil after treatment and most of the remnant heavy metals were bound either to residual fraction or to other not easily mobile fractions of soil. The results of this study indicated that the bioleaching process can be useful for efficient removal of heavy metals from soil. Further, the soil with remnant metals can be disposed off safely.

  11. Bioleaching of nickel from spent petroleum catalyst using Acidithiobacillus thiooxidans DSM- 11478.

    Science.gov (United States)

    Sharma, Mohita; Bisht, Varsha; Singh, Bina; Jain, Pratiksha; Mandal, Ajoy K; Lal, Banwari; Sarma, Priyangshu M

    2015-06-01

    The present work deals with optimization of culture conditions and process parameters for bioleaching of spent petroleum catalyst collected from a petroleum refinery. The efficacy of Ni bioleaching from spent petroleum catalyst was determined using pure culture of Acidithiobacillus thiooxidans DSM- 11478. The culture conditions of pH, temperature and headspace volume to media volume ratio were optimized. EDX analysis was done to confirm the presence of Ni in the spent catalyst after roasting it to decoke its surface. The optimum temperature for A. thiooxidans DSM-11478 growth was found to be 32 degrees C. The enhanced recovery of nickel at very low pH was attributed to the higher acidic strength of sulfuric acid produced in the culture medium by the bacterium. During the bioleaching process, 89% of the Ni present in the catalyst waste could be successfully recovered in optimized conditions. This environment friendly bioleaching process proved efficient than the chemical method. Taking leads from the lab scale results, bioleaching in larger volumes (1, 5 and 10 L) was also performed to provide guidelines for taking up this technology for in situ industrial waste management.

  12. A new strain Acidithiobacillus albertensis BY-05 for bioleaching of metal sulfides ores

    Institute of Scientific and Technical Information of China (English)

    XIA Jin-lan; PENG An-an; HE Huan; YANG Yu; LIU Xue-duan; QIU Guan-zhou

    2007-01-01

    An acidophilic, rod-shaped Gram-negative sulfur oxidizing strain BY-05 was isolated from an acid mine drainage of copper ore in Baiyin area, Gansu Province, China. Ultrastructural studies show that the isolate has a tuft of polar flagella and possesses sulfur granules with clear membrane adhering to the cell innermembrane. Physiological study shows that this isolate grows autotrophically and aerobically by oxidizing S0 and reduced inorganic sulfur compounds (S2O2-3,S2O2-4,S2- and ZnS) with the optimum growth at pH 3.5-4.0 and at the temperature range of 25-30 ℃. The 16S rRNA gene sequence (DQ 423683) of strain BY-05 has 100% sequence similarity to that of Acidithiobacillus albertensis (DSM 14366). So it is identified and named as A. albertensis BY-05. Bioleaching experiments with this new strain show that it can play an important role in recovery of metals from chalcopyrite and sphalerite.

  13. Biosorption and biodegradation of a sulfur dye in high-strength dyeing wastewater by Acidithiobacillus thiooxidans.

    Science.gov (United States)

    Nguyen, Thai Anh; Fu, Chun-Chieh; Juang, Ruey-Shin

    2016-11-01

    The ability of the bacterial strain Acidithiobacillus thiooxidans to remove sulfur blue 15 (SB15) dye from water samples was examined. This bacterium could not only oxidize sulfur compounds to sulfuric acid but also promote the attachment of the cells to the surface of sulfidic particles, therefore serving as an efficient biosorbent. The biosorption isotherms were better described by the Langmuir equation than by the Freundlich or Dubinin-Radushkevich equation. Also, the biosorption process followed the pseudo-second-order kinetics. At pH 8.3 and SB15 concentrations up to 2000 mg L(-1) in the biomass/mineral salt solution, the dye removal and decolorization were 87.5% and 91.4%, respectively, following the biosorption process. Biodegradation was proposed as a subsequent process for the remaining dye (250-350 mg L(-1)). A central composite design was used to analyze independent variables in the response surface methodology study. Under the optimal conditions (i.e., initial dye concentration of 300 mg L(-1), initial biomass concentration of 1.0 g L(-1), initial pH of 11.7, and yeast extract dose of 60 mg L(-1)), up to 50% of SB15 was removed after 4 days of biodegradation.

  14. Influence of the sulfur species reactivity on biofilm conformation during pyrite colonization by Acidithiobacillus thiooxidans.

    Science.gov (United States)

    Lara, René H; García-Meza, J Viridiana; Cruz, Roel; Valdez-Pérez, Donato; González, Ignacio

    2012-08-01

    Massive pyrite (FeS₂) electrodes were potentiostatically modified by means of variable oxidation pulse to induce formation of diverse surface sulfur species (S(n)²⁻, S⁰). The evolution of reactivity of the resulting surfaces considers transition from passive (e.g., Fe(1-x )S₂) to active sulfur species (e.g., Fe(1-x )S(2-y ), S⁰). Selected modified pyrite surfaces were incubated with cells of sulfur-oxidizing Acidithiobacillus thiooxidans for 24 h in a specific culture medium (pH 2). Abiotic control experiments were also performed to compare chemical and biological oxidation. After incubation, the attached cells density and their exopolysaccharides were analyzed by confocal laser scanning microscopy (CLMS) and atomic force microscopy (AFM) on bio-oxidized surfaces; additionally, S(n)²⁻/S⁰ speciation was carried out on bio-oxidized and abiotic pyrite surfaces using Raman spectroscopy. Our results indicate an important correlation between the evolution of S(n)²⁻/S⁰ surface species ratio and biofilm formation. Hence, pyrite surfaces with mainly passive-sulfur species were less colonized by A. thiooxidans as compared to surfaces with active sulfur species. These results provide knowledge that may contribute to establishing interfacial conditions that enhance or delay metal sulfide (MS) dissolution, as a function of the biofilm formed by sulfur-oxidizing bacteria.

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

    Science.gov (United States)

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

    2013-08-01

    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.

  16. Draft Genome Sequence of "Acidibacillus ferrooxidans" ITV01, a Novel Acidophilic Firmicute Isolated from a Chalcopyrite Mine Drainage Site in Brazil.

    Science.gov (United States)

    Dall'Agnol, Hivana; Ñancucheo, Ivan; Johnson, D Barrie; Oliveira, Renato; Leite, Laura; Pylro, Victor S; Holanda, Roseanne; Grail, Barry; Carvalho, Nelson; Nunes, Gisele Lopes; Tzotzos, George; Fernandes, Gabriel Rocha; Dutra, Julliane; Orellana, Sara Cuadros; Oliveira, Guilherme

    2016-03-17

    Here, we report the draft genome sequence of "Acidibacillus ferrooxidans" strain ITV01, a ferrous iron- and sulfide-mineral-oxidizing, obligate heterotrophic, and acidophilic bacterium affiliated with the phylum Firmicutes. Strain ITV01 was isolated from neutral drainage from a low-grade chalcopyrite from a mine in northern Brazil.

  17. Characterization of the uranium (VI) complexes formed by the cells of three A. ferrooxidans eco-types using time-resolved laser-induced fluorescence spectroscopy (TRLFS)

    Energy Technology Data Exchange (ETDEWEB)

    Merroun, M.; Geipel, G.; Selenska-Pobell, S.

    2002-05-01

    TRLFS was used to study the properties of the uranium complexes formed by the cells of the three recently described eco-types of A. ferrooxidans /1/. The results demonstrate that the lifetimes of the complexes are type-specific and are increasing in the same order as the capability of the bacterial strains to accumulate uranium. (orig.)

  18. Bioleaching of arsenic from highly contaminated mine tailings using Acidithiobacillus thiooxidans.

    Science.gov (United States)

    Lee, Eunseong; Han, Yosep; Park, Jeonghyun; Hong, Jeongsik; Silva, Rene A; Kim, Seungkon; Kim, Hyunjung

    2015-01-01

    The behavior of arsenic (As) bioleaching from mine tailings containing high amount of As (ca. 34,000 mg/kg) was investigated using Acidithiobacillus thiooxidans to get an insight on the optimal conditions that would be applied to practical heap and/or tank bioleaching tests. Initial pH (1.8-2.2), temperature (25-40 °C), and solid concentration (0.5-4.0%) were employed as experimental parameters. Complementary characterization experiments (e.g., XRD, SEM-EDS, electrophoretic mobility, cell density, and sulfate production) were also carried out to better understand the mechanism of As bioleaching. The results showed that final As leaching efficiency was similar regardless of initial pH. However, greater initial As leaching rate was observed at initial pH 1.8 than other conditions, which could be attributed to greater initial cell attachment to mine tailings. Unlike the trend observed when varying the initial pH, the final As leaching efficiency varied with the changes in temperature and solid concentration. Specifically, As leaching efficiency tended to decrease with increasing temperature due to the decrease in the bacterial growth rate at higher temperature. Meanwhile, As leaching efficiency tended to increase with decreasing solid concentration. The results for jarosite contents in mine tailings residue after bioleaching revealed that much greater amount of the jarosite was formed during the bioleaching reaction at higher solid concentration, suggesting that the coverage of the surface of the mine tailings by jarosite and/or the co-precipitation of the leached As with jarosite could be a dominant factor reducing As leaching efficiency. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Changes in biofilm structure during the colonization of chalcopyrite by Acidithiobacillus thiooxidans.

    Science.gov (United States)

    García-Meza, J V; Fernández, J J; Lara, R H; González, I

    2013-07-01

    Biofilms of Acidithiobacillus thiooxidans were grown on the surface of massive chalcopyrite electrodes (MCE) where different secondary sulfur phases were previously formed by potentiostatic oxidation of MCE at 0.780≤Ean≤0.965 V (electrooxidized MCE, eMCE). The formation of mainly S⁰ and minor amounts of CuS and Sn²⁻ were detected on eMCEs. The eMCEs were incubated with A. thiooxidans cells for 1, 12, 24, 48, and 120 h in order to temporally monitor changes in eMCE's secondary phases, biofilm structure, and extracellular polymeric substance (EPS) composition (lipids, proteins, and polysaccharides) using microscopic, spectroscopic, electrochemical, and biochemical techniques. The results show significant cell attachments with stratified biofilm structure since the first hour of incubation and EPS composition changes, the most important being production after 48-120 h when the highest amount of lipids and proteins were registered. During 120 h, periodic oxidation/formation of S⁰/Sn²⁻ was recorded on biooxidized eMCEs, until a stable CuS composition was formed. In contrast, no evidence of CuS formation was observed on the eMCEs of the abiotic control, confirming that CuS formation results from microbial activity. The surface transformation of eMCE induces a structural transformation of the biofilm, evolving directly to a multilayered biofilm with more hydrophobic EPS and proteins after 120 h. Our results suggest that A. thiooxidans responded to the spatial and temporal distribution and chemical reactivity of the Sn²⁻/S⁰/CuS phases throughout 120 h. These results suggested a strong correlation between surface speciation, hydrophobic domains in EPS, and biofilm organization during chalcopyrite biooxidation by A. thiooxidans.

  20. Bioleaching of heavy metals from sewage sludge by Acidithiobacillus thiooxidans. A comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Ye-Ming; Wang, Qing-Ping; Chen, Zu-Liang [Fujian Normal Univ., Fuzhou (China). School of Environmental Science and Engineering; Tang, Caixian [La Trobe Univ., Melbourne, VIC (Australia). Dept. of Agricultural Sciences

    2012-06-15

    To understand the bioleaching of metals from sludge by Acidithiobacillus thiooxidans, the aims of this study were to evaluate the experimental conditions affecting the efficiency of removal of the metals, including solids concentration, initial pH, sulfur concentration and inoculum level were examined, and following the bioleaching mechanism was proposed. Materials and methods: A. thiooxidans were isolated from collected sludge samples containing bacteria from Fuzhou Jingshan sewage treatment plant, and identification of bacteria by sequencing the 16 s rDNA gene sequences. Conditions affecting the bioleaching and application were conducted by batch experiments. The analysis of Cr, Cu, Pb, and Zn was carried out using an atomic absorption spectrophotometer, and the pH and oxidation-reduction potential (ORP) were measured using a pH meter and an ORP meter. The results show that a high metal leaching efficiency was achieved at low solid concentrations due to decreases in buffering capacity. In addition, the best conditions of the bioleaching included 2 % (w/{nu}) solid concentration, 5.0 gL{sup -1} sulfur concentration, and 10 % ({nu}/{nu}) inoculum concentration, where the removal efficiencies of Cr, Cu, Pb, and Zn in sewage sludge was 43.6 %, 96.2 %, 41.6 %, and 96.5 %, respectively. We found that the bioleaching of Zn was governed by direct and indirect mechanisms, while the bioleaching of Cu, Pb, and Cr was mainly dominated by the bioleaching indirect mechanism. After processing with the proposed techniques, the heavy metals in the sewage sludge did meet the requirement of the national standards. (orig.)

  1. Influence of the surface speciation on biofilm attachment to chalcopyrite by Acidithiobacillus thiooxidans.

    Science.gov (United States)

    Lara, René H; García-Meza, J Viridiana; González, Ignacio; Cruz, Roel

    2013-03-01

    Surfaces of massive chalcopyrite (CuFeS2) electrodes were modified by applying variable oxidation potential pulses under growth media in order to induce the formation of different secondary phases (e.g., copper-rich polysulfides, S n(2-); elemental sulfur, S(0); and covellite, CuS). The evolution of reactivity (oxidation capacity) of the resulting chalcopyrite surfaces considers a transition from passive or inactive (containing CuS and S n(2-)) to active (containing increasing amounts of S(0)) phases. Modified surfaces were incubated with cells of sulfur-oxidizing bacteria (Acidithiobacillus thiooxidans) for 24 h in a specific culture medium (pH 2). Abiotic control experiments were also performed to compare chemical and biological oxidation. After incubation, the density of cells attached to chalcopyrite surfaces, the structure of the formed biofilm, and their exopolysaccharides and nucleic acids were analyzed by confocal laser scanning microscopy (CLSM) and scanning electron microscopy coupled to dispersive X-ray analysis (SEM-EDS). Additionally, CuS and S n(2-)/S(0) speciation, as well as secondary phase evolution, was carried out on biooxidized and abiotic chalcopyrite surfaces using Raman spectroscopy and SEM-EDS. Our results indicate that oxidized chalcopyrite surfaces initially containing inactive S n(2-) and S n(2-)/CuS phases were less colonized by A. thiooxidans as compared with surfaces containing active phases (mainly S(0)). Furthermore, it was observed that cells were partially covered by CuS and S(0) phases during biooxidation, especially at highly oxidized chalcopyrite surfaces, suggesting the innocuous effect of CuS phases during A. thiooxidans performance. These results may contribute to understanding the effect of the concomitant formation of refractory secondary phases (as CuS and inactive S n(2-)) during the biooxidation of chalcopyrite by sulfur-oxidizing microorganisms in bioleaching systems.

  2. Growth inhibition by tungsten in the sulfur-oxidizing bacterium Acidithiobacillus thiooxidans.

    Science.gov (United States)

    Negishi, Atsunori; Muraoka, Tadashi; Maeda, Terunobu; Takeuchi, Fumiaki; Kanao, Tadayoshi; Kamimura, Kazuo; Sugio, Tsuyoshi

    2005-11-01

    Growth of five strains of sulfur-oxidizing bacteria Acidithiobacillus thiooxidans, including strain NB1-3, was inhibited completely by 50 microM of sodium tungstate (Na(2)WO(4)). When the cells of NB1-3 were incubated in 0.1 M beta-alanine-SO(4)(2-) buffer (pH 3.0) with 100 microM Na(2)WO(4) for 1 h, the amount of tungsten bound to the cells was 33 microg/mg protein. Approximately 10 times more tungsten was bound to the cells at pH 3.0 than at pH 7.0. The tungsten binding to NB1-3 cells was inhibited by oxyanions such as sodium molybdenum and ammonium vanadate. The activities of enzymes involved in elemental sulfur oxidation of NB1-3 cells such as sulfur oxidase, sulfur dioxygenase, and sulfite oxidase were strongly inhibited by Na(2)WO(4). These results indicate that tungsten binds to NB1-3 cells and inhibits the sulfur oxidation enzyme system of the cells, and as a result, inhibits cell growth. When portland cement bars supplemented with 0.075% metal nickel and with 0.075% metal nickel and 0.075% calcium tungstate were exposed to the atmosphere of a sewage treatment plant containing 28 ppm of H(2)S for 2 years, the weight loss of the portland cement bar with metal nickel and calcium tungstate was much lower than the cement bar containing 0.075% metal nickel.

  3. Evolution of biofilms during the colonization process of pyrite by Acidithiobacillus thiooxidans.

    Science.gov (United States)

    González, Dulce M; Lara, René H; Alvarado, Keila N; Valdez-Pérez, Donato; Navarro-Contreras, Hugo R; Cruz, Roel; García-Meza, Jessica Viridiana

    2012-01-01

    We have applied epifluorescence principles, atomic force microscopy, and Raman studies to the analysis of the colonization process of pyrite (FeS(2)) by sulfuroxidizing bacteria Acidithiobacillus thiooxidans after 1, 15, 24, and 72 h. For the stages examined, we present results comprising the evolution of biofilms, speciation of S (n) (2-) /S(0) species, adhesion forces of attached cells, production and secretion of extracellular polymeric substances (EPS), and its biochemical composition. After 1 h, highly dispersed attached cells in the surface of the mineral were observed. The results suggest initial non-covalent, weak interactions (e.g., van der Waal's, hydrophobic interactions), mediating an irreversible binding mechanism to electrooxidized massive pyrite electrode (eMPE), wherein the initial production of EPS by individual cells is determinant. The mineral surface reached its maximum cell cover between 15 to 24 h. Longer biooxidation times resulted in the progressive biofilm reduction on the mineral surface. Quantification of attached cell adhesion forces indicated a strong initial mechanism (8.4 nN), whereas subsequent stages of mineral colonization indicated stability of biofilms and of the adhesion force to an average of 4.2 nN. A variable EPS (polysaccharides, lipids, and proteins) secretion at all stages was found; thus, different architectural conformation of the biofilms was observed during 120 h. The main EPS produced were lipopolysaccharides which may increase the hydrophobicity of A. thiooxidans biofilms. The highest amount of lipopolysaccharides occurred between 15-72 h. In contrast with abiotic surfaces, the progressive depletion of S (n) (2-) /S(0) was observed on biotic eMPE surfaces, indicating consumption of surface sulfur species. All observations indicated a dynamic biooxidation mechanism of pyrite by A. thiooxidans, where the biofilms stability and composition seems to occur independently from surface sulfur species depletion.

  4. Architecture and gene repertoire of the flexible genome of the extreme acidophile Acidithiobacillus caldus.

    Directory of Open Access Journals (Sweden)

    Lillian G Acuña

    Full Text Available BACKGROUND: Acidithiobacillus caldus is a sulfur oxidizing extreme acidophile and the only known mesothermophile within the Acidithiobacillales. As such, it is one of the preferred microbes for mineral bioprocessing at moderately high temperatures. In this study, we explore the genomic diversity of A. caldus strains using a combination of bioinformatic and experimental techniques, thus contributing first insights into the elucidation of the species pangenome. PRINCIPAL FINDINGS: Comparative sequence analysis of A. caldus ATCC 51756 and SM-1 indicate that, despite sharing a conserved and highly syntenic genomic core, both strains have unique gene complements encompassing nearly 20% of their respective genomes. The differential gene complement of each strain is distributed between the chromosomal compartment, one megaplasmid and a variable number of smaller plasmids, and is directly associated to a diverse pool of mobile genetic elements (MGE. These include integrative conjugative and mobilizable elements, genomic islands and insertion sequences. Some of the accessory functions associated to these MGEs have been linked previously to the flexible gene pool in microorganisms inhabiting completely different econiches. Yet, others had not been unambiguously mapped to the flexible gene pool prior to this report and clearly reflect strain-specific adaption to local environmental conditions. SIGNIFICANCE: For many years, and because of DNA instability at low pH and recurrent failure to genetically transform acidophilic bacteria, gene transfer in acidic environments was considered negligible. Findings presented herein imply that a more or less conserved pool of actively excising MGEs occurs in the A. caldus population and point to a greater frequency of gene exchange in this econiche than previously recognized. Also, the data suggest that these elements endow the species with capacities to withstand the diverse abiotic and biotic stresses of natural

  5. Simultaneous removal of H2S and NH3 in biofilter inoculated with Acidithiobacillus thiooxidans TAS.

    Science.gov (United States)

    Lee, Eun Young; Cho, Kyung-Suk; Ryu, Hee Wook

    2005-06-01

    H2S and NH3 gases are toxic, corrosive and malodorous air pollutants. Although there are numerous well-established physicochemical techniques presently available for the treatment of these gases, the growing demand for a more economical and improved process has prompted investigations into biological alternatives. In biological treatment methods, H2S is oxidized to SO4(2-) by sulfur-oxidizing bacteria, and then NH3 is removed by chemical neutralization with SO4(2-) to (NH4)2SO4. Since the accumulated (NH4)2SO4 can inhibit microbial activity, it is important to utilize an effective sulfur-oxidizing bacterium that has tolerance to high concentrations of (NH4)2SO4 for the simultaneous removal of H2S and NH3. In this study, a sulfur-oxidizing bacterium with tolerance to high concentrations of (NH4)2SO4 was isolated from activated sludge and identified as Acidithiobacillus thiooxidans TAS. A. thiooxidans TAS could display its sulfur-oxidizing activity in a medium supplemented with 60 g.l(-1) (NH4)2SO4, even though its growth and sulfur-oxidizing activity were completely inhibited in 80 g.l(-1) (NH4)2SO4. When H2S alone was supplied to a ceramic biofilter inoculated with A. thiooxidans TAS, an almost 100% H2S removal efficiency was maintained until the inlet H2S concentration was increased up to 900 microl.l(-1) and the space velocity up to 500 h(-1), at which the amount of H2S eliminated was 810 g-S.m(-3).h(-1). However, when NH3 (50-500 microl.l(-1)) was simultaneously supplied to the biofilter with H2S, the maximum amount of H2S eliminated decreased to 650 g-S.m(-3).h(-1). The inhibition of H2S removal by low NH3 concentrations (50-200 microl.l(-1)) was similar to that by high NH3 concentrations (300-500 microl.l(-1)). The critical inlet H2S load that resulted in over 99% removal was determined as 400 g-S.m(-3).h(-1) in the presence of NH3.

  6. Removal of hydrogen sulfide by sulfate-resistant Acidithiobacillus thiooxidans AZ11.

    Science.gov (United States)

    Lee, Eun Young; Lee, Nae Yoon; Cho, Kyung-Suk; Ryu, Hee Wook

    2006-04-01

    Toxic H2S gas is an important industrial pollutant that is applied to biofiltration. Here, we examined the effects of factors such as inlet concentration and space velocity on the removal efficiency of a bacterial strain capable of tolerating high sulfate concentrations and low pH conditions. We examined three strains of Acidithiobacillus thiooxidans known to have sulfur-oxidizing activity, and identified strain AZ11 as having the highest tolerance for sulfate. A. thiooxidans AZ11 could grow at pH 0.2 in the presence of 74 g l(-1) sulfate, the final oxidation product of elemental sulfur, in the culture broth. Under these conditions, the specific sulfur oxidation rate was 2.9 g-S g-DCW (dry cell weight)(-1) d(-1). The maximum specific sulfur oxidation rate of A. thiooxidans AZ11 was 21.2 g-S g-DCW(-1) d(-1), which was observed in the presence of 4.2 g-SO4(2-) l(-1) and pH 1.5, in the culture medium. To test the effects of various factors on biofiltration by this strain, A. thiooxidans AZ11 was inoculated into a porous ceramic biofilter. First, a maximum inlet loading of 670 g-S m(-3) h(-1) was applied with a constant space velocity (SV) of 200 h(-1) (residence time, 18 s) and the inlet concentration of H2S was experimentally increased from 200 ppmv to 2200 ppmv. Under these conditions, less than 0.1 ppmv H2S was detected at the biofilter outlet. When the inlet H2S was maintained at a constant concentration of 200 ppmv and the SV was increased from 200 h(-1) to 400 h(-1) (residence time, 9 s), an H2S removal of 99.9% was obtained. However, H2S removal efficiencies decreased to 98% and 94% when the SV was set to 500 h(-1) (residence time, 7.2 s) and 600 h(-1) (residence time, 6 s), respectively. The critical elimination capacity guaranteeing 96% removal of the inlet H2S was determined to be 160 g-S m(-3) h(-1) at a space velocity of 600 h(-1). Collectively, these findings show for the first time that a sulfur oxidizing bacterium has a high sulfate tolerance and a high

  7. Influence of initial pH on bioleaching of heavy metals from contaminated soil employing indigenous Acidithiobacillus thiooxidans.

    Science.gov (United States)

    Kumar, R Naresh; Nagendran, R

    2007-01-01

    Bioleaching of heavy metals from contaminated soil was carried out employing indigenous sulfur oxidizing bacterium Acidithiobacillus thiooxidans. Experiments were carried out to assess the influence of initial pH of the system on bioleaching of chromium, zinc, copper, lead and cadmium from metal contaminated soil. pH at the end of four weeks of bioleaching at different initial pH of 3-7 was between 0.9 and 1.3, ORP between 567 and 617mV and sulfate production was in the range of 6090-8418mgl(-1). Chromium, zinc, copper, lead and cadmium solubilization ranged from "59% to 98%" at different initial pH. A. thiooxidans was not affected by the increasing pH of the bioleaching system towards neutral and it was able to utilize elemental sulfur. The results of the present study are encouraging to develop the bioleaching process for decontamination of heavy metal contaminated soil.

  8. Changes in nutrient profile of soil subjected to bioleaching for removal of heavy metals using Acidithiobacillus thiooxidans

    Energy Technology Data Exchange (ETDEWEB)

    NareshKumar, R. [Centre for Environmental Studies, Anna University, Chennai 600025 (India)], E-mail: nareshkrish@hotmail.com; Nagendran, R. [Centre for Environmental Studies, Anna University, Chennai 600025 (India)

    2008-08-15

    Studies were carried out to assess changes in nitrogen, phosphorus and potassium contents in soil during bioleaching of heavy metals from soil contaminated by tannery effluents. Indigenous sulfur oxidizing bacteria Acidithiobacillus thiooxidans isolated from the contaminated soil were used for bioremediation. Solubilization efficiency of chromium, cadmium, copper and zinc from soil was 88, 93, 92 and 97%, respectively. However, loss of nitrogen, phosphorus and potassium from the soil was 30, 70 and 68%, respectively. These findings indicate that despite its high potential for removal of heavy metals from contaminated soils, bioleaching results in undesirable dissolution/loss of essential plant nutrients. This aspect warrants urgent attention and detailed studies to evaluate the appropriateness of the technique for field application.

  9. Changes in nutrient profile of soil subjected to bioleaching for removal of heavy metals using Acidithiobacillus thiooxidans.

    Science.gov (United States)

    NareshKumar, R; Nagendran, R

    2008-08-15

    Studies were carried out to assess changes in nitrogen, phosphorus and potassium contents in soil during bioleaching of heavy metals from soil contaminated by tannery effluents. Indigenous sulfur oxidizing bacteria Acidithiobacillus thiooxidans isolated from the contaminated soil were used for bioremediation. Solubilization efficiency of chromium, cadmium, copper and zinc from soil was 88, 93, 92 and 97%, respectively. However, loss of nitrogen, phosphorus and potassium from the soil was 30, 70 and 68%, respectively. These findings indicate that despite its high potential for removal of heavy metals from contaminated soils, bioleaching results in undesirable dissolution/loss of essential plant nutrients. This aspect warrants urgent attention and detailed studies to evaluate the appropriateness of the technique for field application.

  10. Atuação de Acidithiobacillus na solubilização de fosfato natural em solo de tabuleiro cultivado com jacatupé (Pachyrhizus erosus Effect of Acidithiobacillus on solubilization of natural phosphate in a coastal tableland soil under yam bean (Pachyrhizus erosus crop

    Directory of Open Access Journals (Sweden)

    N. P. Stamford

    2004-02-01

    Full Text Available Realizou-se um experimento em casa de vegetação para avaliar a atuação do enxofre (S inoculado com Acidithiobacillus na disponibilidade de fósforo (P de fosfato natural (FN, em diferentes modos de aplicação do fertilizante, em um Espodossolo Ferrocárbico Órtico, do tabuleiro costeiro da Zona da Mata de Pernambuco, cultivado com jacatupé (Pachyrhizus erosus. As plantas foram inoculadas com rizóbio (NFB 747 e NFB 748 e adicionado tratamento-controle sem inoculação com rizóbio. Os tratamentos com P foram: (1 FN revestindo o enxofre inoculado com Acidithiobacillus (FN S*, (2 FN revestido com S e com Acidithiobacillus (S* FN, (3 mistura FN com S e com Acidithiobacillus (FN + S*, (4 mistura FN com S e sem Acidithiobacillus (FN + S, (5 superfosfato triplo (ST e (6 sem aplicação de fósforo (P0. Os tratamentos foram aplicados: (a na superfície, (b em sulco 10 cm abaixo da semente, e (c em sulco 10 cm abaixo e ao lado da semente. A biomassa nodular foi maior no tratamento (FN + S* com melhor efeito quando aplicado ao lado e abaixo das sementes. O (FN + S* também aumentou a altura das plantas, a biomassa da parte aérea e das túberas e o N total da parte aérea, especialmente quando aplicado 10 cm abaixo das sementes. O P total da parte aérea foi mais elevado com (S* FN aplicado 10 cm abaixo das sementes. Os melhores teores de P no solo foram obtidos com (FN + S* e (S* FN, com efeito mais evidente quando aplicados 10 cm abaixo das sementes.A greenhouse experiment was carried out to evaluate the effect of sulphur (S inoculated with Acidithiobacillus on phosphorus (P availability from natural phosphate (NP using different fertilizer application methods on yam bean (Pachyrhizus erosus grown in a "Tableland Forest" soil (Podzol Hydromorphic dystrophic of the "Zona da Mata" in the State of Pernambuco, Brazil. Plants were inoculated with rhizobia strains (NFN 747 and NFB 748 and control treatments added without rhizobia inoculation. The P

  11. Charge and softness of the outer part of the cell wall of Thiobacillus ferrooxidans in the low ionic strength medium

    Directory of Open Access Journals (Sweden)

    Škvarla Jiří

    2002-03-01

    Full Text Available The surface charge and surface potential are parameters influencing the microbial adhesion phenomenon through the electrostatic interaction between bacteria and substrates. The Smoluchowski equation, originally developed for estimating the above parameters from the experimentally accessible electrophoretic mobility of rigid colloid particles, is however inapplicable to the elastic bacterial cells. The problem is that the outer cell wall of bacteria is a layer with a complex polyelectrolyte structure. In this article, the OhshimaLs model of the gsofth particle is applied to describe the surface electrostatics of Thiobacillus ferrooxidans cells by measuring their electrophoretic mobility in distilled water as a function of a (low ionic strength and pH. In this model, the rigid core is considered to be covered with a charged ion-penetrable layer of polyelectrolytes. Two model parameters have been determined by the curve fitting at pH from 3.2 to 5.8, namely the number density of the dissociated groups N and the softness parameter 1/ƒÉ of the polyelectrolyte layer of the bacterium. A disagreement of the best fit parameters (evaluated by the correlation coefficient with the analogous parameters determined for other colloids (including bacterial cells in aqueous solutions of a high ionic strength is discussed.

  12. Research on the growth condition of Acidithiobacillus thiooxidans TT03%氧化硫硫杆菌(Acidithiobacillus thiooxidans)TT03的生长条件研究

    Institute of Scientific and Technical Information of China (English)

    党阿丽; 郭立姝; 陈立娟; 曹亚彬; 于丽萍; 殷博; 甄涛

    2013-01-01

    针对前期筛选鉴定的氧化硫硫杆菌(Acidithiobacillus thiooxidans) TT03,为进一步了解和掌握其培养方法进行了本项研究.结果表明:TT03适宜在初始pH2.0~6.0与温度25℃~35℃的范围内生长;以硫酸铵为第一氮源,也可利用尿素和硝酸盐生长;为保证稳定的培养,需要加大接种量到2.0%以上;适量的氧气供给对TT03的生长是有利的;在二氧化碳的浓度达6%以上时生长受到抑制,而在6%以下时,对TT03的生长有促进作用.

  13. System-level understanding of the potential acid-tolerance components of Acidithiobacillus thiooxidans ZJJN-3 under extreme acid stress.

    Science.gov (United States)

    Feng, Shoushuai; Yang, Hailin; Wang, Wu

    2015-09-01

    In previous study, two extremely acidophilic strains Acidithiobacillus thiooxidans ZJJN-3 (collection site: bioleaching leachate) and ZJJN-5 (collection site: bioleaching wastewater) were isolated from a typical industrial bio-heap in China. Here, we unraveled the potential acid-tolerance components of ZJJN-3 by comparing the physiological differences with ZJJN-5 under different acid stresses. The parameters used for comparison included intracellular pH (pHin), capsule morphology, fatty acid composition of cell membrane, transcription of key molecular chaperones, H(+)-ATPase activities and NAD(+)/NADH ratio. It was indicated that the acid-tolerance of A. thiooxidans ZJJN-3 was systematically regulated. Capsule first thickened and then shed off along with increased acid stress. Cell membrane maintained the intracellular stability by up-regulating the proportion of unsaturated fatty acid and cyclopropane fatty acids. Meanwhile, the transcription of key repair molecular chaperones (GrpE-DnaK-DnaJ) was up-regulated by 2.2-3.5 folds for ensuring the proper folding of peptide. Moreover, low pHin promoted ZJJN-3 to biosynthesize more H(+)-ATPase for pumping H(+) out of cells. Furthermore, the NAD(+)/NADH ratio increased due to the decreased H(+) concentration. Based on the above physiological analysis, the potential acid-tolerance components of A. thiooxidans ZJJN-3 were first proposed and it would be useful for better understanding how these extremophiles responded to the high acid stress.

  14. Optimization of two-step bioleaching of spent petroleum refinery catalyst by Acidithiobacillus thiooxidans using response surface methodology.

    Science.gov (United States)

    Srichandan, Haragobinda; Pathak, Ashish; Kim, Dong Jin; Lee, Seoung-Won

    2014-01-01

    A central composite design (CCD) combined with response surface methodology (RSM) was employed for maximizing bioleaching yields of metals (Al, Mo, Ni, and V) from as-received spent refinery catalyst using Acidithiobacillus thiooxidans. Three independent variables, namely initial pH, sulfur concentration, and pulp density were investigated. The pH was found to be the most influential parameter with leaching yields of metals varying inversely with pH. Analysis of variance (ANOVA) of the quadratic model indicated that the predicted values were in good agreement with experimental data. Under optimized conditions of 1.0% pulp density, 1.5% sulfur and pH 1.5, about 93% Ni, 44% Al, 34% Mo, and 94% V was leached from the spent refinery catalyst. Among all the metals, V had the highest maximum rate of leaching (Vmax) according to the Michaelis-Menten equation. The results of the study suggested that two-step bioleaching is efficient in leaching of metals from spent refinery catalyst. Moreover, the process can be conducted with as received spent refinery catalyst, thus making the process cost effective for large-scale applications.

  15. The effects of metabolites from the indigenous Acidithiobacillus thiooxidans and temperature on the bioleaching of cadmium from soil.

    Science.gov (United States)

    Liu, Hsuan-Liang; Chiu, Chi-Wei; Cheng, Yang-Chu

    2003-09-20

    The effect of metabolites from the indigenous Acidithiobacillus thiooxidans and temperature on the bioleaching of cadmium from soil was investigated in the present study. Bioleaching was found to be more effective than chemical leaching of cadmium. The metabolite, mainly sulfuric acid, which was shown to be growth-associated in the exponential phase, plays a major role in bioleaching. The maximum amount of cadmium leached was obtained after 8 days of precultivation when cells were directly involved in the leaching process. It indicates that cells in the exponential growth phase exhibit higher activity toward bioleaching. In contrast, the maximum amount of cadmium leached and the maximum initial rate for bioleaching were reached after 16 days of precultivation when only metabolites were involved in the bioleaching process. It implies that higher sulfuric acid concentration results in higher leaching efficiency. In addition, higher temperature leads to higher leaching efficiency. The optimal operation condition for bioleaching was determined to be a two-stage process: The first stage involves the precultivation of the indigenous A. thiooxidans at 30 degrees C for 8 days followed by 20 minutes of centrifugation to discard cells. The second stage involves the bioleaching with the subsequent supernatant at 50 degrees C.

  16. Comparative study of nickel resistance of pure culture and co-culture of Acidithiobacillus thiooxidans and Leptospirillum ferriphilum.

    Science.gov (United States)

    Xu, Ying; Yin, Huaqun; Jiang, Huidan; Liang, Yili; Guo, Xue; Ma, Liyuan; Xiao, Yunhua; Liu, Xueduan

    2013-09-01

    The effect of Ni²⁺ on the growth and functional gene expression of the pure culture and co-culture of Acidithiobacillus thiooxidans and Leptospirillum ferriphilum has been studied. Compared with the pure culture, the co-culture showed a stronger sulfur and ferrous ion oxidation activity. At 100 mM, A. thiooxidans in co-culture grew faster and had 48 h shorter lag phases. The cell number of A. thiooxidans in co-culture was about 5 times higher than that in pure culture. The existence of A. thiooxidans in co-culture activated the expression of some metal resistance genes in L. ferriphilum at least 16 h in advance. A. thiooxidans in co-culture tends to chose more efficient pathways to transport nickel ion, ensuring the export of heavy metal was faster and more effective than that in pure culture. All the data indicated that there were synergetic interactions between iron- and sulfur-oxidizing bacteria under the stress of Ni²⁺.

  17. Mechanism of electro-generating leaching of chalcopyrite-MnO2 in presence of Acidithiobacillus thiooxidans

    Institute of Scientific and Technical Information of China (English)

    XIAO Li; LIU Jian-she; FANG Zheng; QIU Guan-zhou

    2008-01-01

    A dual cell system with chalcopyrite anode and MnO2 cathode was used to study the relations between time and such data as the electric quantity and the dissolution rates of the two minerals in the electro-generating leaching(EGL) and the bio-electro-generating leaching(BEGL),respectively.The results showed that the dissolution rates for Cu2+ and Fe2+ in BEGL were almost 2 times faster than those in EGL,and nearly 3 times for Mn2+; the electric output increased nearly by 3 times.The oxidation residue of chalcopyrite was represented by TEM and XRD,whose pattern was similar to that of the raw ore in EGL.The mechanism for leaching of CuFeS2-MnO2 in the presence of Acidithiobacillus thiooxidans was proposed as a successive reaction of two independent sub-processes for the anode.The first stage,common to both processes,is dissolution of chalcopyrite to produce Cu2+,Fe2+ and sulfur.The second stage is subsequent oxidization of sulfur only in BEGL,which is the controlling step of the process.However,the dissolution of MnO2 lasts until the reaction of chalcopyrite stops or the ores exhaust in two types of leaching.

  18. Existence of aa3-type ubiquinol oxidase as a terminal oxidase in sulfite oxidation of Acidithiobacillus thiooxidans.

    Science.gov (United States)

    Sugio, Tsuyoshi; Hisazumi, Tomohiro; Kanao, Tadayoshi; Kamimura, Kazuo; Takeuchi, Fumiaki; Negishi, Atsunori

    2006-07-01

    It was found that Acidithiobacillus thiooxidans has sulfite:ubiquinone oxidoreductase and ubiquinol oxidase activities in the cells. Ubiquinol oxidase was purified from plasma membranes of strain NB1-3 in a nearly homogeneous state. A purified enzyme showed absorption peaks at 419 and 595 nm in the oxidized form and at 442 and 605 nm in the reduced form. Pyridine ferrohaemochrome prepared from the enzyme showed an alpha-peak characteristic of haem a at 587 nm, indicating that the enzyme contains haem a as a component. The CO difference spectrum of ubiquinol oxidase showed two peaks at 428 nm and 595 nm, and a trough at 446 nm, suggesting the existence of an aa(3)-type cytochrome in the enzyme. Ubiquinol oxidase was composed of three subunits with apparent molecular masses of 57 kDa, 34 kDa, and 23 kDa. The optimum pH and temperature for ubiquinol oxidation were pH 6.0 and 30 degrees C. The activity was completely inhibited by sodium cyanide at 1.0 mM. In contrast, the activity was inhibited weakly by antimycin A(1) and myxothiazol, which are inhibitors of mitochondrial bc(1) complex. Quinone analog 2-heptyl-4-hydoroxyquinoline N-oxide (HOQNO) strongly inhibited ubiquinol oxidase activity. Nickel and tungstate (0.1 mM), which are used as a bacteriostatic agent for A. thiooxidans-dependent concrete corrosion, inhibited ubiquinol oxidase activity 100 and 70% respectively.

  19. Hydrogen sulfide oxidation in novel Horizontal-Flow Biofilm Reactors dominated by an Acidithiobacillus and a Thiobacillus species.

    Science.gov (United States)

    Gerrity, S; Kennelly, C; Clifford, E; Collins, G

    2016-09-01

    Hydrogen Sulfide (H2S) is an odourous, highly toxic gas commonly encountered in various commercial and municipal sectors. Three novel, laboratory-scale, Horizontal-Flow Biofilm Reactors (HFBRs) were tested for the removal of H2S gas from air streams over a 178-day trial at 10°C. Removal rates of up to 15.1 g [H2S] m(-3) h(-1) were achieved, demonstrating the HFBRs as a feasible technology for the treatment of H2S-contaminated airstreams at low temperatures. Bio-oxidation of H2S in the reactors led to the production of H(+) and sulfate (SO(2-)4) ions, resulting in the acidification of the liquid phase. Reduced removal efficiency was observed at loading rates of 15.1 g [H2S] m(-3) h(-1). NaHCO3 addition to the liquid nutrient feed (synthetic wastewater (SWW)) resulted in improved H2S removal. Bacterial diversity, which was investigated by sequencing and fingerprinting 16S rRNA genes, was low, likely due to the harsh conditions prevailing in the systems. The HFBRs were dominated by two species from the genus Acidithiobacillus and Thiobacillus. Nonetheless, there were significant differences in microbial community structure between distinct HFBR zones due to the influence of alkalinity, pH and SO4 concentrations. Despite the low temperature, this study indicates HFBRs have an excellent potential to biologically treat H2S-contaminated airstreams.

  20. 氧化亚铁硫杆菌对金属铜的加工%BIOMACHINING OF METAL COPPEY BY THIOBACILLUS FERROOXIDANS

    Institute of Scientific and Technical Information of China (English)

    李雅芹; 张德远; 吴依陶

    2000-01-01

    Thiobacillus ferrooxidans was employed in the biomachining process of metal copper(Cuo). The bacteria growth and the changes of Fe3+ concentration during machining processes have been studied. Biomachining and chemical machining have been compared.The results showed that the concentrations of bacteria and Fe3+ determine the speed of machining copper. The biomachining is more fast that chemical maching because bacteria are able to regenerate Fe3+ oxidizing copper. It was also found that the Cu2 + produced from the machining processes inhibit the growth of bacteria. Cu2+ has to be removed.

  1. Effects of microorganisms on surface properties of chalcopyrite and bioleaching

    Institute of Scientific and Technical Information of China (English)

    CHEN Ming-lian; ZHANG Lin; GU Guo-hua; HU Yue-hua; SU Li-jun

    2008-01-01

    The alteration of surface properties of chalcopyrite after biological conditioning with Acidithiobacillus ferrooxidans and Acidithiobacillus caldus was evaluated by Zeta-potential,adsorption studies,FT-IR spectra and contact angle measurement.The Zeta-potential studies show that the iso-electric point(IEP) of chalcopyrite after bacterial treatment moves towards the IEP of pure cells,indicating the adsorption of cells on chalcopyrite surface.The FT-IR spectra of chalcopyrite treated with bacterial cells show the presence of the cell functional groups signifying cells adsorption.Due to the formation of elemental sulfur and intermediate copper sulphides on chalcopyrite surface,the contact angle and surface hydrophobicity of chalcopyrite increase at the initial bioleaching stage.Chalcopyrite bioleaching by Acidithiobacillus ferrooxidans has higher copper extraction,which agrees with the fact that Acidithiobacillus ferrooxidans adsorbed on chalcopyrite surface is much more than Acidithiobacillus caldus.The results support the direct mechanism of sulfide oxidations in bioleaching chalcopyrite.

  2. The Effect of Oxygen Supply on the Dual Growth Kinetics of Acidithiobacillus thiooxidans under Acidic Conditions for Biogas Desulfurization

    Directory of Open Access Journals (Sweden)

    Hyeong-Kyu Namgung

    2015-01-01

    Full Text Available In this study, to simulate a biogas desulfurization process, a modified Monod-Gompertz kinetic model incorporating a dissolved oxygen (DO effect was proposed for a sulfur-oxidizing bacterial (SOB strain, Acidithiobacillus thiooxidans, under extremely acidic conditions of pH 2. The kinetic model was calibrated and validated using experimental data obtained from a bubble-column bioreactor. The SOB strain was effective for H2S degradation, but the H2S removal efficiency dropped rapidly at DO concentrations less than 2.0 mg/L. A low H2S loading was effectively treated with oxygen supplied in a range of 2%–6%, but a H2S guideline of 10 ppm could not be met, even with an oxygen supply greater than 6%, when the H2S loading was high at a short gas retention time of 1 min and a H2S inlet concentration of 5000 ppm. The oxygen supply should be increased in the aerobic desulfurization to meet the H2S guideline; however, the excess oxygen above the optimum was not effective because of the decline in oxygen efficiency. The model estimation indicated that the maximum H2S removal rate was approximately 400 ppm/%-O2 at the influent oxygen concentration of 4.9% under the given condition. The kinetic model with a low DO threshold for the interacting substrates was a useful tool to simulate the effect of the oxygen supply on the H2S removal and to determine the optimal oxygen concentration.

  3. The σ(54)-dependent two-component system regulating sulfur oxidization (Sox) system in Acidithiobacillus caldus and some chemolithotrophic bacteria.

    Science.gov (United States)

    Li, Li-Feng; Fu, Luo-Jie; Lin, Jian-Qun; Pang, Xin; Liu, Xiang-Mei; Wang, Rui; Wang, Zhao-Bao; Lin, Jian-Qiang; Chen, Lin-Xu

    2017-03-01

    The sulfur oxidization (Sox) system is the central sulfur oxidization pathway of phototrophic and chemotrophic sulfur-oxidizing bacteria. Regulation and function of the Sox system in the chemotrophic Paracoccus pantotrophus has been elucidated; however, to date, no information is available on the regulation of this system in the chemolithotrophic Acidithiobacillus caldus, which is widely utilized in bioleaching. We described the novel tspSR-sox-like clusters in A. caldus and other chemolithotrophic sulfur-oxidizing bacteria containing Sox systems. The highly homologous σ(54)-dependent two-component signaling system (TspS/R), upstream of the sox operons in these novel clusters, was identified by phylogenetic analyses. A typical σ(54)-dependent promoter, P1, was identified upstream of soxX-I in the sox-I cluster of A. caldus MTH-04. The transcriptional start site (G) and the -12/-24 regions (GC/GG) of P1 were determined by rapid amplification of cDNA ends (5'RACE), and the upstream activator sequences (UASs; TGTCCCAAATGGGACA) were confirmed by electrophoretic mobility shift assays (EMSAs) in vitro and by UAS-probe-plasmids assays in vivo. Sequence analysis of promoter regions in tspSR-sox-like clusters revealed that there were similar σ(54)-dependent promoters upstream of the soxX genes. Based on our results, we proposed a TspSR-mediated signal transduction and transcriptional regulation pathway for the Sox system in A. caldus. The regulation of σ(54)-dependent two-component systems (TCSs) for Sox pathways were explained for the first time in A. caldus, A. thiooxidans, T. tepidarius, and T. denitrificans, indicating the significance of modulating the sulfur oxidization in these chemolithotrophic sulfur oxidizers.

  4. Insights on the structure and stability of Licanantase: a trimeric acid-stable coiled-coil lipoprotein from Acidithiobacillus thiooxidans

    Directory of Open Access Journals (Sweden)

    Fernando Abarca

    2014-08-01

    Full Text Available Licanantase (Lic is the major component of the secretome of Acidithiobacillus thiooxidans when grown in elemental sulphur. When used as an additive, Lic improves copper recovery from bioleaching processes. However, this recovery enhancement is not fully understood. In this context, our aim is to predict the 3D structure of Lic, to shed light on its structure-function relationships. Bioinformatics analyses on the amino acid sequence of Lic showed a great similarity with Lpp, an Escherichia coli Lipoprotein that can form stable trimers in solution. Lic and Lpp share the secretion motif, intracellular processing and alpha helix structure, as well as the distribution of hydrophobic residues in heptads forming a hydrophobic core, typical of coiled-coil structures. Cross-linking experiments showed the presence of Lic trimers, supporting our predictions. Taking the in vitro and in silico evidence as a whole, we propose that the most probable structure for Lic is a trimeric coiled-coil. According to this prediction, a suitable model for Lic was produced using the de novo algorithm “Rosetta Fold-and-Dock”. To assess the structural stability of our model, Molecular Dynamics (MD and Replica Exchange MD simulations were performed using the structure of Lpp and a 14-alanine Lpp mutant as controls, at both acidic and neutral pH. Our results suggest that Lic was the most stable structure among the studied proteins in both pH conditions. This increased stability can be explained by a higher number of both intermonomer hydrophobic contacts and hydrogen bonds, key elements for the stability of Lic’s secondary and tertiary structure.

  5. The effect of oxygen supply on the dual growth kinetics of Acidithiobacillus thiooxidans under acidic conditions for biogas desulfurization.

    Science.gov (United States)

    Namgung, Hyeong-Kyu; Song, JiHyeon

    2015-02-01

    In this study, to simulate a biogas desulfurization process, a modified Monod-Gompertz kinetic model incorporating a dissolved oxygen (DO) effect was proposed for a sulfur-oxidizing bacterial (SOB) strain, Acidithiobacillus thiooxidans, under extremely acidic conditions of pH 2. The kinetic model was calibrated and validated using experimental data obtained from a bubble-column bioreactor. The SOB strain was effective for H2S degradation, but the H2S removal efficiency dropped rapidly at DO concentrations less than 2.0 mg/L. A low H2S loading was effectively treated with oxygen supplied in a range of 2%-6%, but a H2S guideline of 10 ppm could not be met, even with an oxygen supply greater than 6%, when the H2S loading was high at a short gas retention time of 1 min and a H2S inlet concentration of 5000 ppm. The oxygen supply should be increased in the aerobic desulfurization to meet the H2S guideline; however, the excess oxygen above the optimum was not effective because of the decline in oxygen efficiency. The model estimation indicated that the maximum H2S removal rate was approximately 400 ppm/%-O2 at the influent oxygen concentration of 4.9% under the given condition. The kinetic model with a low DO threshold for the interacting substrates was a useful tool to simulate the effect of the oxygen supply on the H2S removal and to determine the optimal oxygen concentration.

  6. Bacterial CS2 hydrolases from Acidithiobacillus thiooxidans strains are homologous to the archaeal catenane CS2 hydrolase.

    Science.gov (United States)

    Smeulders, Marjan J; Pol, Arjan; Venselaar, Hanka; Barends, Thomas R M; Hermans, John; Jetten, Mike S M; Op den Camp, Huub J M

    2013-09-01

    Carbon disulfide (CS(2)) and carbonyl sulfide (COS) are important in the global sulfur cycle, and CS(2) is used as a solvent in the viscose industry. These compounds can be converted by sulfur-oxidizing bacteria, such as Acidithiobacillus thiooxidans species, to carbon dioxide (CO(2)) and hydrogen sulfide (H2S), a property used in industrial biofiltration of CS(2)-polluted airstreams. We report on the mechanism of bacterial CS(2) conversion in the extremely acidophilic A. thiooxidans strains S1p and G8. The bacterial CS(2) hydrolases were highly abundant. They were purified and found to be homologous to the only other described (archaeal) CS(2) hydrolase from Acidianus strain A1-3, which forms a catenane of two interlocked rings. The enzymes cluster in a group of β-carbonic anhydrase (β-CA) homologues that may comprise a subclass of CS(2) hydrolases within the β-CA family. Unlike CAs, the CS(2) hydrolases did not hydrate CO(2) but converted CS(2) and COS with H(2)O to H(2)S and CO(2). The CS(2) hydrolases of A. thiooxidans strains G8, 2Bp, Sts 4-3, and BBW1, like the CS(2) hydrolase of Acidianus strain A1-3, exist as both octamers and hexadecamers in solution. The CS(2) hydrolase of A. thiooxidans strain S1p forms only octamers. Structure models of the A. thiooxidans CS(2) hydrolases based on the structure of Acidianus strain A1-3 CS(2) hydrolase suggest that the A. thiooxidans strain G8 CS(2) hydrolase may also form a catenane. In the A. thiooxidans strain S1p enzyme, two insertions (positions 26 and 27 [PD] and positions 56 to 61 [TPAGGG]) and a nine-amino-acid-longer C-terminal tail may prevent catenane formation.

  7. Chemical and surface analysis during evolution of arsenopyrite oxidation by Acidithiobacillus thiooxidans in the presence and absence of supplementary arsenic.

    Science.gov (United States)

    Ramírez-Aldaba, Hugo; Valles, O Paola; Vazquez-Arenas, Jorge; Rojas-Contreras, J Antonio; Valdez-Pérez, Donato; Ruiz-Baca, Estela; Meraz-Rodríguez, Mónica; Sosa-Rodríguez, Fabiola S; Rodríguez, Ángel G; Lara, René H

    2016-10-01

    Bioleaching of arsenopyrite presents a great interest due to recovery of valuable metals and environmental issues. The current study aims to evaluate the arsenopyrite oxidation by Acidithiobacillus thiooxidans during 240h at different time intervals, in the presence and absence of supplementary arsenic. Chemical and electrochemical characterizations are carried out using Raman, AFM, SEM-EDS, Cyclic Voltammetry, EIS, electrophoretic and adhesion forces to comprehensively assess the surface behavior and biooxidation mechanism of this mineral. These analyses evidence the formation of pyrite-like secondary phase on abiotic control surfaces, which contrast with the formation of pyrite (FeS2)-like, orpiment (As2S3)-like and elementary sulfur and polysulfide (Sn(2-)/S(0)) phases found on biooxidized surfaces. Voltammetric results indicate a significant alteration of arsenopyrite due to (bio)oxidation. Resistive processes determined with EIS are associated with chemical and electrochemical reactions mediated by (bio)oxidation, resulting in the transformation of arsenopyrite surface and biofilm direct attachment. Charge transfer resistance is increased when (bio)oxidation is performed in the presence of supplementary arsenic, in comparison with lowered abiotic control resistances obtained in its absence; reinforcing the idea that more stable surface products are generated when As(V) is in the system. Biofilm structure is mainly comprised of micro-colonies, progressively enclosed in secondary compounds. A more compact biofilm structure with enhanced formation of secondary compounds is identified in the presence of supplementary arsenic, whereby variable arsenopyrite reactivity is linked and attributed to these secondary compounds, including Sn(2-)/S(0), pyrite-like and orpiment-like phases.

  8. Insights on the structure and stability of Licanantase: a trimeric acid-stable coiled-coil lipoprotein from Acidithiobacillus thiooxidans.

    Science.gov (United States)

    Abarca, Fernando; Gutierrez-Maldonado, Sebastian E; Parada, Pilar; Martinez, Patricio; Maass, Alejandro; Perez-Acle, Tomas

    2014-01-01

    Licanantase (Lic) is the major component of the secretome of Acidithiobacillus thiooxidans when grown in elemental sulphur. When used as an additive, Lic improves copper recovery from bioleaching processes. However, this recovery enhancement is not fully understood. In this context, our aim is to predict the 3D structure of Lic, to shed light on its structure-function relationships. Bioinformatics analyses on the amino acid sequence of Lic showed a great similarity with Lpp, an Escherichia coli Lipoprotein that can form stable trimers in solution. Lic and Lpp share the secretion motif, intracellular processing and alpha helix structure, as well as the distribution of hydrophobic residues in heptads forming a hydrophobic core, typical of coiled-coil structures. Cross-linking experiments showed the presence of Lic trimers, supporting our predictions. Taking the in vitro and in silico evidence as a whole, we propose that the most probable structure for Lic is a trimeric coiled-coil. According to this prediction, a suitable model for Lic was produced using the de novo algorithm "Rosetta Fold-and-Dock". To assess the structural stability of our model, Molecular Dynamics (MD) and Replica Exchange MD simulations were performed using the structure of Lpp and a 14-alanine Lpp mutant as controls, at both acidic and neutral pH. Our results suggest that Lic was the most stable structure among the studied proteins in both pH conditions. This increased stability can be explained by a higher number of both intermonomer hydrophobic contacts and hydrogen bonds, key elements for the stability of Lic's secondary and tertiary structure.

  9. The Effect of Oxygen Supply on the Dual Growth Kinetics of Acidithiobacillus thiooxidans under Acidic Conditions for Biogas Desulfurization

    Science.gov (United States)

    Namgung, Hyeong-Kyu; Song, JiHyeon

    2015-01-01

    In this study, to simulate a biogas desulfurization process, a modified Monod-Gompertz kinetic model incorporating a dissolved oxygen (DO) effect was proposed for a sulfur-oxidizing bacterial (SOB) strain, Acidithiobacillus thiooxidans, under extremely acidic conditions of pH 2. The kinetic model was calibrated and validated using experimental data obtained from a bubble-column bioreactor. The SOB strain was effective for H2S degradation, but the H2S removal efficiency dropped rapidly at DO concentrations less than 2.0 mg/L. A low H2S loading was effectively treated with oxygen supplied in a range of 2%–6%, but a H2S guideline of 10 ppm could not be met, even with an oxygen supply greater than 6%, when the H2S loading was high at a short gas retention time of 1 min and a H2S inlet concentration of 5000 ppm. The oxygen supply should be increased in the aerobic desulfurization to meet the H2S guideline; however, the excess oxygen above the optimum was not effective because of the decline in oxygen efficiency. The model estimation indicated that the maximum H2S removal rate was approximately 400 ppm/%-O2 at the influent oxygen concentration of 4.9% under the given condition. The kinetic model with a low DO threshold for the interacting substrates was a useful tool to simulate the effect of the oxygen supply on the H2S removal and to determine the optimal oxygen concentration. PMID:25633028

  10. The Effects of Amino Acid Nutrition of Lag Phase in Growth of Thiobacillus ferrooxidans%氨基酸营养对At.f菌生长迟缓期的影响

    Institute of Scientific and Technical Information of China (English)

    张一

    2011-01-01

    [Objective] The effects of amino acid nutrition of lag phase in growth of thiobacillus ferrooxidans were researched. [Methods] The thiobacillus ferrooxidans were cultured in 20 different amino acids culture mediums. Use potassium dichromate titration to determination the u-tilization of Fe2+ all time, and the pH change of culture medium after added amino acids were studied. [ Results ] Non-polar amino acids have better effect to reduce the Lag phase of thiobacillus ferrooxidans, phenylalanine, tyrosine, proline and tryptophan also have similar effects. Ser-ine, glutamine and histidine are inhibited to reduced lag phase of thiobacillus ferrooxidans. [ Conclusion ] Non-polar amino acids can shorten the lag phase of thiobacillus ferrooxidans effectively, and several polar amino acids have the opposite effects.%[目的]研究氨基酸营养对At.f菌生长迟缓期的影响.[方法]将At.f在分别加入20种氨基酸的培养基中培养,利用重铬酸钾滴定法测定各时段Fe2+利用情况,并检测添加氨基酸后培养基pH的变化.[结果]非极性氨基酸对缩短At.f菌的迟缓期的效果较明显;苯丙氨酸、酪氨酸、脯氨酸、色氨酸四种成环氨基酸有较好的效果;丝氨酸、谷氨酰胺、组氨酸有明显的抑制作用.[结论]非极性氨基酸能有效缩短At.f菌生长迟缓期,部分极性氨基酸则起到相反效果.

  11. Iron meteorites can support the growth of acidophilic chemolithoautotrophic microorganisms.

    Science.gov (United States)

    González-Toril, Elena; Martínez-Frías, Jesús; Gómez Gómez, José María; Rull, Fernando; Amils, Ricardo

    2005-06-01

    Chemolithoautotrophy based on reduced inorganic minerals is considered a primitive energy transduction system. Evidence that a high number of meteorites crashed into the planet during the early period of Earth history led us to test the ability of iron-oxidizing bacteria to grow using iron meteorites as their source of energy. Here we report the growth of two acidophilic iron-oxidizing bacteria, Leptospirillum ferrooxidans and Acidithiobacillus ferrooxidans, on a piece of the Toluca meteorite as the only source of energy. The alteration of the surface of the exposed piece of meteorite, the solubilization of its oxidized metal constituents, mainly ferric iron, and the formation of goethite precipitates all clearly indicate that iron-meteorite-based chemolithotrophic metabolism is viable.

  12. Use of an acidophilic yeast strain to enable the growth of leaching bacteria on solid media.

    Science.gov (United States)

    Ngom, Baba; Liang, Yili; Liu, Yi; Yin, Huaqun; Liu, Xueduan

    2015-03-01

    In this study, a Candida digboiensis strain was isolated from a heap leaching plant in Zambia and used in double-layer agar plate to efficiently isolate and purify leaching bacteria. Unlike Acidiphilium sp., the yeast strain was tetrathionate tolerant and could metabolize a great range of organic compounds including organic acids. These properties allowed the yeast strain to enable and fasten the growth of iron and sulfur oxidizers on double-layer agar plate. The isolates were identified as Acidithiobacillus ferrooxidans FOX1, Leptospirillun ferriphilum BN, and Acidithiobacillus thiooxidans ZMB. These three leaching bacteria were inhibited by organic acids such as acetic and propionic acids; however, their activities were enhanced by Candida digboiensis NB under dissolved organic matter stress.

  13. A versatile and efficient markerless gene disruption system for Acidithiobacillus thiooxidans: application for characterizing a copper tolerance related multicopper oxidase gene.

    Science.gov (United States)

    Wen, Qing; Liu, Xiangmei; Wang, Huiyan; Lin, Jianqun

    2014-11-01

    The acidophilic bioleaching bacteria can usually survive in high concentrations of copper ions because of their special living environment. However, little is known about the copper homeostatic mechanisms of Acidithiobacillus thiooxidans, an important member of bioleaching bacteria. Here, a putative multicopper oxidase gene (cueO) was detected from the draft genome of A. thiooxidans ATCC 19377. The transcriptional level of cueO in response to 10 mM CuSO₄was upregulated 25.01 ± 2.59 folds. The response of P(cueO) to copper was also detected and might be stimulated by a putative CueR protein. Then, by using the counter-selectable marker lacZ and enhancing the expression of endonuclease I-SceI with tac promoter, a modified markerless gene disruption system was developed and the cueO gene disruption mutant (ΔcueO) of A. thiooxidans was successfully constructed with a markedly improved second homologous recombination frequency of 0.28 ± 0.048. The ΔcueO mutant was more sensitive to external copper and nearly completely lost the phenoloxidase activity; however, the activity could be restored after complementing the cueO gene. All results suggest the close relation of cueO gene to copper tolerance in A. thiooxidans. In addition, the developed efficient markerless gene knockout method can also be introduced into other Acidithiobacillus strains.

  14. Isolation and characterization of Acidithiobacillus caldus from a sulfur-oxidizing bacterial biosensor and its role in detection of toxic chemicals.

    Science.gov (United States)

    Hassan, Sedky H A; Van Ginkel, Steven W; Kim, Sung-Min; Yoon, Sung-Hwan; Joo, Jin-Ho; Shin, Beom-Soo; Jeon, Byong-Hun; Bae, Wookeun; Oh, Sang-Eun

    2010-08-01

    A novel toxicity detection methodology based on sulfur-oxidizing bacteria (SOB) has been developed for the rapid and reliable detection of toxic chemicals in water. The methodology exploits the ability of SOB to oxidize sulfur particles in the presence of oxygen to produce sulfuric acid. The reaction results in an increase in electrical conductivity (EC) and a decrease in pH. The assay is based on the inhibition of SOB in the presence of toxic chemicals by measuring changes in EC and pH. We found that SOB biosensor can detect toxic chemicals, such as heavy metals and CN-, in the 5-2000ppb range. One bacterium was isolated from an SOB biosensor and the 16S rRNA gene of the bacterial strain has 99% and 96% sequence similarity to Acidithiobacillus sp. ORCS6 and Acidithiobacillus caldus DSM 8584, respectively. The isolate was identified as A. caldus SMK. The SOB biosensor is ideally suited for monitoring toxic chemicals in water having the advantages of high sensitivity and quick detection.

  15. Chemical and surface analysis during evolution of arsenopyrite oxidation by Acidithiobacillus thiooxidans in the presence and absence of supplementary arsenic

    Energy Technology Data Exchange (ETDEWEB)

    Ramírez-Aldaba, Hugo [Facultad de Ciencias Químicas, Departamento de Ciencia de Materiales, Universidad Juárez del Estado de Durango (UJED), Av. Veterinaria S/N, Circuito Universitario, Col. Valle del Sur, 34120 Durango, Dgo (Mexico); Valles, O. Paola [Facultad de Ciencias Químicas, Departamento de Ciencia de Materiales, Universidad Juárez del Estado de Durango (UJED), Av. Veterinaria S/N, Circuito Universitario, Col. Valle del Sur, 34120 Durango, Dgo (Mexico); Instituto Tecnológico de Durando, UPIDET, Av. Felipe Pescador 1830 Ote. Col. Nueva Vizcaya, 34080 Durango, Dgo (Mexico); Vazquez-Arenas, Jorge [Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, Iztapalapa, México DF 09340 (Mexico); Rojas-Contreras, J. Antonio [Instituto Tecnológico de Durando, UPIDET, Av. Felipe Pescador 1830 Ote. Col. Nueva Vizcaya, 34080 Durango, Dgo (Mexico); Valdez-Pérez, Donato [Instituto Politécnico Nacional, UPALM, Edif. Z-4 3er Piso, CP 07738 México D.F (Mexico); Ruiz-Baca, Estela [Facultad de Ciencias Químicas, Departamento de Ciencia de Materiales, Universidad Juárez del Estado de Durango (UJED), Av. Veterinaria S/N, Circuito Universitario, Col. Valle del Sur, 34120 Durango, Dgo (Mexico); and others

    2016-10-01

    Bioleaching of arsenopyrite presents a great interest due to recovery of valuable metals and environmental issues. The current study aims to evaluate the arsenopyrite oxidation by Acidithiobacillus thiooxidans during 240 h at different time intervals, in the presence and absence of supplementary arsenic. Chemical and electrochemical characterizations are carried out using Raman, AFM, SEM-EDS, Cyclic Voltammetry, EIS, electrophoretic and adhesion forces to comprehensively assess the surface behavior and biooxidation mechanism of this mineral. These analyses evidence the formation of pyrite-like secondary phase on abiotic control surfaces, which contrast with the formation of pyrite (FeS{sub 2})-like, orpiment (As{sub 2}S{sub 3})-like and elementary sulfur and polysulfide (S{sub n}{sup 2−}/S{sup 0}) phases found on biooxidized surfaces. Voltammetric results indicate a significant alteration of arsenopyrite due to (bio)oxidation. Resistive processes determined with EIS are associated with chemical and electrochemical reactions mediated by (bio)oxidation, resulting in the transformation of arsenopyrite surface and biofilm direct attachment. Charge transfer resistance is increased when (bio)oxidation is performed in the presence of supplementary arsenic, in comparison with lowered abiotic control resistances obtained in its absence; reinforcing the idea that more stable surface products are generated when As(V) is in the system. Biofilm structure is mainly comprised of micro-colonies, progressively enclosed in secondary compounds. A more compact biofilm structure with enhanced formation of secondary compounds is identified in the presence of supplementary arsenic, whereby variable arsenopyrite reactivity is linked and attributed to these secondary compounds, including S{sub n}{sup 2−}/S{sup 0}, pyrite-like and orpiment-like phases. - Highlights: • Biofilm structures occur as compact micro-colonies. • Surface transformation reactions control arsenopyrite and cell

  16. In situ spectroscopy on intact Leptospirillum ferrooxidans reveals that reduced cytochrome 579 is an obligatory intermediate in the aerobic iron respiratory chain

    Directory of Open Access Journals (Sweden)

    Robert C Blake

    2012-04-01

    Full Text Available Electron transfer reactions among colored biomolecules in intact bacterial cells were monitored using an integrating cavity absorption meter that permitted the acquisition of accurate absorbance data in suspensions of cells that scatter light. The aerobic iron respiratory chain of Leptospirillum ferrooxidans was dominated by the redox status of an abundant cellular cytochrome that had an absorbance peak at 579 nanometers in the reduced state. Intracellular cytochrome 579 was reduced within the time that it took to mix a suspension of the bacteria with soluble ferrous iron at pH 1.7. Steady state turnover experiments were conducted where the initial concentrations of ferrous iron were less than or equal to that of the oxygen concentration. Under these conditions, the initial absorbance spectrum of the oxidized bacterium was always regenerated from that of the iron-reduced bacterium. The kinetics of aerobic respiration on soluble iron by intact L. ferrooxidans conformed to the Michaelis-Menten formalism, where the reduced intracellular cytochrome 579 represented the Michaelis complex whose subsequent oxidation appeared to be the rate-limiting step in the overall aerobic respiratory process. The velocity of formation of ferric iron at any time point was directly proportional to the concentration of the reduced cytochrome 579. Further, the integral over time of the concentraton of the reduced cytochrome was directly proportional to the total concentration of ferrous iron in each reaction mixture. These kinetic data obtained using whole cells were consistent with the hypothesis that reduced cytochrome 579 is an obligatory steady state intermediate in the iron respiratory chain of this bacterium. The capability of conducting visible spectroscopy in suspensions of intact cells comprises a powerful post-reductionist means to study cellular respiration in situ under physiological conditions for the organism.

  17. Aplicação de técnicas eletroquímicas no estudo da dissolução oxidativa da covelita (CuS por Thiobacillus ferrooxidans Electrochemical techniques applied to study the oxidative dissolution of the covellite: CuS by Thiobacillus ferrooxidans

    Directory of Open Access Journals (Sweden)

    Christiane Medina Teixeira

    2002-02-01

    Full Text Available Among the copper sulphides, chalcopyrite (CuFeS2, covellite (CuS and chalcocite (Cu2S are the most important source of minerals for copper mining industry. The acknowledge of behaviour of these sulphides related with bacterial leaching process are essential for optimization procedures. Despite of its importance, covellite has not deserved much interest of researchers regarding this matter. In this work it was studied the oxidation of covellite by the chemolithotrophic bacterium Thiobacillus ferrooxidans by using electrochemical techniques, such as open circuit potentials with the time and cyclic voltammetry. The experiments were carried out in acid medium (pH 1.8, containing or not Fe2+ as additional energy source, and in different periods of incubation; chemical controls were run in parallel. The results showed that a sulphur layer is formed spontaneously due the acid attack, covering the sulphide in the initial phase of incubation, blocking the sulphide oxidation. However, the bacterium was capable to oxidize this sulphur layer. In the presence of Fe2+ as supplemental energy source, the corrosion process was facilitated, because ocurred an indirect oxidation of covellite by Fe3+, which was produced by T. ferrooxidans oxidation of the Fe2+ added in the medium.

  18. Isolation and characterization of a novel Acidithiobacillus ferrivorans strain from the Chilean Altiplano: attachment and biofilm formation on pyrite at low temperature.

    Science.gov (United States)

    Barahona, Sergio; Dorador, Cristina; Zhang, Ruiyong; Aguilar, Pablo; Sand, Wolfgang; Vera, Mario; Remonsellez, Francisco

    2014-11-01

    Microorganisms are used to aid the extraction of valuable metals from low-grade sulfide ores in mines worldwide, but relatively little is known about this process in cold environments. This study comprises a preliminary analysis of the bacterial diversity of the polyextremophilic acid River Aroma located in the Chilean Altiplano, and revealed that Betaproteobacteria was the most dominant bacterial group (Gallionella-like and Thiobacillus-like). Taxa characteristic of leaching environments, such Acidithiobacillus and Leptospirillum, were detected at low abundances. Also, bacteria not associated with extremely acidic, metal-rich environments were found. After enrichment in iron- and sulfur-oxidizing media, we isolated and identified a novel psychrotolerant Acidithiobacillus ferrivorans strain ACH. This strain can grow using ferrous iron, sulfur, thiosulfate, tetrathionate and pyrite, as energy sources. Optimal growth was observed in the presence of pyrite, where cultures reached a cell number of 6.5 · 10(7) cells mL(-1). Planktonic cells grown with pyrite showed the presence of extracellular polymeric substances (10 °C and 28 °C), and a high density of cells attached to pyrite grains were observed at 10 °C by electron microscopy. The attachment of cells to pyrite coupons and the presence of capsular polysaccharides were visualized by using epifluorescence microscopy, through nucleic acid and lectin staining with Syto(®)9 and TRITC-Con A, respectively. Interestingly, we observed high cell adhesion including the formation of microcolonies within 21 days of incubation at 4 °C, which was correlated with a clear induction of capsular polysaccharides production. Our data suggests that attachment to pyrite is not temperature-dependent in At. ferrivorans ACH. The results of this study highlight the potential of this novel psychrotolerant strain in oxidation and attachment to minerals under low-temperature conditions.

  19. Diguanylate cyclase null mutant reveals that C-Di-GMP pathway regulates the motility and adherence of the extremophile bacterium Acidithiobacillus caldus.

    Science.gov (United States)

    Castro, Matías; Deane, Shelly M; Ruiz, Lina; Rawlings, Douglas E; Guiliani, Nicolas

    2015-01-01

    An understanding of biofilm formation is relevant to the design of biological strategies to improve the efficiency of the bioleaching process and to prevent environmental damages caused by acid mine/rock drainage. For this reason, our laboratory is focused on the characterization of the molecular mechanisms involved in biofilm formation in different biomining bacteria. In many bacteria, the intracellular levels of c-di-GMP molecules regulate the transition from the motile planktonic state to sessile community-based behaviors, such as biofilm development, through different kinds of effectors. Thus, we recently started a study of the c-di-GMP pathway in several biomining bacteria including Acidithiobacillus caldus. C-di-GMP molecules are synthesized by diguanylate cyclases (DGCs) and degraded by phosphodiesterases (PDEs). We previously reported the existence of intermediates involved in c-di-GMP pathway from different Acidithiobacillus species. Here, we report our work related to At. caldus ATCC 51756. We identified several putative-ORFs encoding DGC and PDE and effector proteins. By using total RNA extracted from At. caldus cells and RT-PCR, we demonstrated that these genes are expressed. We also demonstrated the presence of c-di-GMP by mass spectrometry and showed that genes for several of the DGC enzymes were functional by heterologous genetic complementation in Salmonella enterica serovar Typhimurium mutants. Moreover, we developed a DGC defective mutant strain (Δc1319) that strongly indicated that the c-di-GMP pathway regulates the swarming motility and adherence to sulfur surfaces by At. caldus. Together, our results revealed that At. caldus possesses a functional c-di-GMP pathway which could be significant for ores colonization during the bioleaching process.

  20. Bioremoval of Hydrogen Sulfide by Acidithiobacillus thiooxidans%氧化硫硫杆菌脱除硫化氢的研究

    Institute of Scientific and Technical Information of China (English)

    晏磊; 刘权; 张爽; 王伟东; 王彦杰; 荆瑞勇

    2014-01-01

    The bioremoval characteristics of hydrogen sulfide by Acidithiobacillus thiooxidans ATCC19377 (A. thiooxidans ATCC19377) were investigated as a function of pH,operation time,gas flow,initial hydrogen sulfide concentration and bacterial biomass dosage (OD600).The removal conditions of hydrogen sulfide were analyzed by the single-factor experiments.Results indicated that the optimum conditions for hydrogen sulfide removal were pH 2.5,operation time 180 min,gas flow 40 mL·min-1,initial hydrogen sulfide concentration 8 g·m -3 and bacterial biomass dosage (OD600)0.40.Establishment of bioremoval conditions could provide theoretic foundation for industrial desulfurization of gas.%研究利用Acidithiobacillus thiooxidans ATCC19377(A. thiooxidans ATCC19377)对硫化氢的脱除条件进行研究,考察pH,反应器运行时间,气流量,初始硫化氢浓度以及细菌生物量即600 nm处吸收值(OD600)对脱除效能的影响。采用单因素实验法对A. thiooxidans脱除硫化氢的条件进行了研究。A. thiooxidans脱除硫化氢的最佳条件为:pH 2.5、反应器运行时间180 min、气体流量40 mL·min-1、初始硫化氢浓度8 g·m-3、细菌生物量即600 nm处吸收值0.40。初步确定了A. thiooxidans脱除硫化氢的条件,为工业气体脱硫提供理论依据。

  1. 化学合成独立栄養細菌 Acidithiobacillus thiooxidans 由来アコニターゼの遺伝子解析と大腸菌での発現

    OpenAIRE

    金原, 陽平; 田村, 隆; 徳田, 千束; 中村, 淳雄; 松川, 寛和; 稲垣, 賢二

    2005-01-01

    An aconitase from Acidithiobacillus thiooxidans was purified and characterized, and its gene was cloned. The cloned aconitase gene (acn) was expressed in Escherichia coli JM 109; aconitase activity was found in the cell extarct. The acn gene encodes a 646-amino acid polypeptide and is located upstream of the isocitrate dehydrogenase gene (icd). A. thiooxidans aconitase showes high sequence similar to pig heart aconitase and E.coli aconitase B. Twenty-five of twenty-seven active site residues ...

  2. Cowpea nodulation, biomass yield and nutrient uptake, as affected by biofertilizers and rhizobia, in a sodic soil amended with Acidithiobacillus - doi: 10.4025/actasciagron.v35i4.16994

    Directory of Open Access Journals (Sweden)

    Newton Pereira Stamford

    2013-05-01

    Full Text Available Sodic soils require application of amendments as gypsum and organic matter. Many types of compost have been tested in sodic soils reclamation; however, these materials often do not provide satisfactory pH reduction. A recent study reported effective effects applying mixture of gypsum and sulfur inoculated with Acidithiobacillus in sodic soils with high pH and exchangeable sodium, though the effects on plant parameters were not evaluated. The present study was conducted to verify the effects of BPK rock biofertilizers on nodulation, biomass yield and nutrient uptake in cowpea compared with mineral fertilizer after sodic soil amendment. The BPK biofertilizers and PK mineral fertilizer were applied at different rates, and plants were inoculated with effective rhizobia strains. A control that did not receive PK fertilization was included. The results indicated that gypsum and sulfur with Acidithiobacillus reduced the soil’s pH and the amount of soil exchangeable sodium. BPK rock biofertilizer increased cowpea nodulation, biomass yield and nutrient uptake. The native rhizobia in the soil exhibited effectiveness in cowpea growth; displaying similar results compared with the rhizobia inoculated plants. BPK biofertilizers may be used as alternative to mineral PK fertilizers in sodic soils after the application of gypsum and sulfur inoculated with Acidithiobacillus.

  3. Biological leaching of Mn, Al, Zn, Cu and Ti in an anaerobic sewage sludge effectuated by Thiobacillus ferrooxidans and its effect on metal partitioning.

    Science.gov (United States)

    Lombardi, Ana T; Garcia, Oswaldo

    2002-07-01

    The chemical fractionation and bioleaching of Mn, Al, Zn, Cu and Ti in municipal sewage sludge were investigated using Thiobacillus ferrooxidans as leaching microorganism. As a result of the bacterial activity, ORP increase and pH reduction were observed. Metal solubilization was accomplished only in experimental systems supplemented with energy source (Fe(II)). The solubilization efficiency approached approximately 80% for Mn and Zn, 24% for Cu, 10% for Al and 0.2% for Ti. The chemical fractionation of Mn, Al, Zn, Cu and Ti was investigated using a five-step sequential extraction procedure employing KNO3, KF, Na4P2O7, EDTA and HNO3. The results show that the bioleaching process affected the partitioning of Mn and Zn, increasing its percentage of elution in the KNO3 fraction while reducing it in the KF, Na4P2O7 and EDTA fractions. No significant effect was detected on the partitioning of Cu and Al. However, quantitatively the metals Mn, Zn, Cu and Al were extracted with higher efficiency after the bacterial activity. Titanium was unaffected by the bioleaching process in both qualitative and quantitative aspects.

  4. Influence of organics and silica on Fe(II) oxidation rates and cell-mineral aggregate formation by the green-sulfur Fe(II)-oxidizing bacterium Chlorobium ferrooxidans KoFox - Implications for Fe(II) oxidation in ancient oceans

    Science.gov (United States)

    Gauger, Tina; Byrne, James M.; Konhauser, Kurt O.; Obst, Martin; Crowe, Sean; Kappler, Andreas

    2016-06-01

    Most studies on microbial phototrophic Fe(II) oxidation (photoferrotrophy) have focused on purple bacteria, but recent evidence points to the importance of green-sulfur bacteria (GSB). Their recovery from modern ferruginous environments suggests that these photoferrotrophs can offer insights into how their ancient counterparts grew in Archean oceans at the time of banded iron formation (BIF) deposition. It is unknown, however, how Fe(II) oxidation rates, cell-mineral aggregate formation, and Fe-mineralogy vary under environmental conditions reminiscent of the geological past. To address this, we studied the Fe(II)-oxidizer Chlorobium ferrooxidans KoFox, a GSB living in co-culture with the heterotrophic Geospirillum strain KoFum. We investigated the mineralogy of Fe(III) metabolic products at low/high light intensity, and in the presence of dissolved silica and/or fumarate. Silica and fumarate influenced the crystallinity and particle size of the produced Fe(III) minerals. The presence of silica also enhanced Fe(II) oxidation rates, especially at high light intensities, potentially by lowering Fe(II)-toxicity to the cells. Electron microscopic imaging showed no encrustation of either KoFox or KoFum cells with Fe(III)-minerals, though weak associations were observed suggesting co-sedimentation of Fe(III) with at least some biomass via these aggregates, which could support diagenetic Fe(III)-reduction. Given that GSB are presumably one of the most ancient photosynthetic organisms, and pre-date cyanobacteria, our findings, on the one hand, strengthen arguments for photoferrotrophic activity as a likely mechanism for BIF deposition on a predominantly anoxic early Earth, but, on the other hand, also suggest that preservation of remnants of Fe(II)-oxidizing GSB as microfossils in the rock record is unlikely.

  5. Effects of Arsenite Resistance on the Growth and Functional Gene Expression of Leptospirillum ferriphilum and Acidithiobacillus thiooxidans in Pure Culture and Coculture

    Directory of Open Access Journals (Sweden)

    Huidan Jiang

    2015-01-01

    Full Text Available The response of iron-oxidizing Leptospirillum ferriphilum YSK and sulfur-oxidizing Acidithiobacillus thiooxidans A01 to arsenite under pure culture and coculture was investigated based on biochemical characterization (concentration of iron ion and pH value and related gene expression. L. ferriphilum YSK and At. thiooxidans A01 in pure culture could adapt up to 400 mM and 800 mM As(III after domestication, respectively, although arsenite showed a negative effect on both strains. The coculture showed a stronger sulfur and ferrous ion oxidation activity when exposed to arsenite. In coculture, the pH value showed no significant difference when under 500 mM arsenite stress, and the cell number of At. thiooxidans was higher than that in pure culture benefiting from the interaction with L. ferriphilum. The expression profile showed that the arsenic efflux system in the coculture was more active than that in pure culture, indicating that there is a synergetic interaction between At. thiooxidans A01 and L. ferriphilum YSK. In addition, a model was proposed to illustrate the interaction between arsenite and the ars operon in L. ferriphilum YSK and At. thiooxidans A01. This study will facilitate the effective application of coculture in the bioleaching process by taking advantage of strain-strain communication and coordination.

  6. Effects of Arsenite Resistance on the Growth and Functional Gene Expression of Leptospirillum ferriphilum and Acidithiobacillus thiooxidans in Pure Culture and Coculture.

    Science.gov (United States)

    Jiang, Huidan; Liang, Yili; Yin, Huaqun; Xiao, Yunhua; Guo, Xue; Xu, Ying; Hu, Qi; Liu, Hongwei; Liu, Xueduan

    2015-01-01

    The response of iron-oxidizing Leptospirillum ferriphilum YSK and sulfur-oxidizing Acidithiobacillus thiooxidans A01 to arsenite under pure culture and coculture was investigated based on biochemical characterization (concentration of iron ion and pH value) and related gene expression. L. ferriphilum YSK and At. thiooxidans A01 in pure culture could adapt up to 400 mM and 800 mM As(III) after domestication, respectively, although arsenite showed a negative effect on both strains. The coculture showed a stronger sulfur and ferrous ion oxidation activity when exposed to arsenite. In coculture, the pH value showed no significant difference when under 500 mM arsenite stress, and the cell number of At. thiooxidans was higher than that in pure culture benefiting from the interaction with L. ferriphilum. The expression profile showed that the arsenic efflux system in the coculture was more active than that in pure culture, indicating that there is a synergetic interaction between At. thiooxidans A01 and L. ferriphilum YSK. In addition, a model was proposed to illustrate the interaction between arsenite and the ars operon in L. ferriphilum YSK and At. thiooxidans A01. This study will facilitate the effective application of coculture in the bioleaching process by taking advantage of strain-strain communication and coordination.

  7. The Investigation of the Colony Isolation of Thiobacillus Ferrooxidans%氧化亚铁硫杆菌的菌落分离研究

    Institute of Scientific and Technical Information of China (English)

    张在海; 邱冠周; 胡岳华; 柳建设

    2001-01-01

    以琼脂为凝固剂,研究了亚铁含量、磷酸盐含量、pH值 、添加硫氰酸钾对氧化亚铁硫杆菌菌落产生的影响和细菌的再培养。结果表明培养基能否有 效供给酸耗用酸,使凝固剂不被酸降解(胨化),使细菌能够稳定固着生长、繁殖是菌落产生 的关键条件。控制好这些条件,可以使菌落数量比9K固体培养基提高近两个数量级。%The effect of contents of ferrous ion and phosphate salt,pH,and potassium thiocyanate on the colony formation of Thiobacillus ferrooxidans and the subculture of the bacterrium in the presence of agar as solidifying agent have been investigated.The results have showed that the critical condition for the colony formation is whether the culture medium can steadly supply the acid for baterial oxidation to prevent agar from peptoned and keep invariable pH for the inoculum,in which the bacterium can stably anchorage on the medium for growth and multiplication;and controlling these conditions,the number of colonies can be two orders of magnitude larger than 9K solid medium.

  8. 氧化硫硫杆菌对难选恩施赤铁矿脱磷的影响%Study on Application ofAcidithiobacillus thiooxidans in Dephosphorization of Hematite in Enshi

    Institute of Scientific and Technical Information of China (English)

    孙灵芝; 李士琦; 汪玉娇; 高金涛; 吴龙; 金晓晖

    2011-01-01

    Dephosphorization of phosphorus-containing 0.90% high-phosphorus hematite ore in Enshi with the strain of Acidithiobacillus thiooxidans (At.t) was studied. The preliminary results showed that the maximum dephosphorization rate could reach up to 71%, which meant that Acidithiobacillus thiooxidans had a better dephosphorization effect. 10% of the strain concentration, 75 urn of hematite particles, 4.0 of initial culture pH value were obtained as the optimized leaching conditions by studying the growth characteristics of At.t and effects of different pH values, hematite particle sizes and At.t concentrations on the bioleaching process.%利用嗜酸性氧化硫硫杆菌(Acidithiobacillus thiooxidans,At.t)菌种,对含磷为0.90%的恩施高磷赤铁矿进行了微生物降磷实验.对At.t浓度、培养基初始pH值和赤铁矿粒度对磷浸出效果的影响进行了系统研究.结果表明,用At.t对高磷赤铁矿进行磷浸出的最佳工艺条件为:At.t浓度10%,培养基初始pH值4.0,赤铁矿粒度75 μm,在此条件下得到的磷磷浸出率高达71%,At.t具有较好的降磷效果.

  9. Effects of ferrous sulfate, inoculum history, and anionic form on lead, zinc, and copper toxicity to Acidithiobacillus caldus strain BC13

    Energy Technology Data Exchange (ETDEWEB)

    John E. Aston; William A. Apel; Brady D. Lee; Brent M. Peyton

    2010-12-01

    The current study reports the single and combined toxicities of Pb, Zn, and Cu to Acidithiobacillus caldus strain BC13. The observed half-maximal inhibitory concentrations (IC50),?±?95% confidence intervals, for Pb, Zn, and Cu were 0.9?±?0.1?mM, 39?±?0.5?mM, and 120?±?8?mM, respectively. The observed minimum inhibitory concentrations (MIC) for Pb, Zn, and Cu were 7.5?mM, 75?mM, and 250?mM, respectively. When metals were presented in binary mixtures, the toxicities were less than additive. For example, when 50% of the Pb MIC and 50% of the Cu MIC were presented together, the specific growth rate was inhibited by only 59?±?3%, rather than 100%. In addition, the presence of ferrous iron in the growth media decreased Pb and Zn toxicity to A. caldus strain BC13. The importance of inoculum history was evaluated by pre-adapting cultures through subsequent transfers in the presence of Pb, Zn, and Cu at their respective IC50s. After pre-adaptation, cultures had specific growth rates 39?±?11, 32?±?7, and 28?±?12% higher in the presence of Pb, Zn, and Cu IC50s, respectively, compared with cultures that had not been pre-adapted. In addition, when cells exposed to the MICs of Pb, Zn, and Cu were harvested, washed, and re-inoculated into fresh, metal-free medium, they grew, showing that the cells remained viable with little residual toxicity. Finally, metal chlorides showed more toxicity than metal sulfates, and studies using sodium chloride or a mixture of metal sulfates and sodium chloride suggested that this was attributable to an additive combination of the metal and chloride toxicities. Environ. Toxicol. Chem. 2010;29:2669–2675. © 2010 SETAC

  10. Metabolic acidosis

    Science.gov (United States)

    Acidosis - metabolic ... Metabolic acidosis occurs when the body produces too much acid. It can also occur when the kidneys are not ... the body. There are several types of metabolic acidosis. Diabetic acidosis develops when acidic substances, known as ...

  11. Metabolic neuropathies

    Science.gov (United States)

    Neuropathy - metabolic ... can be caused by many different things. Metabolic neuropathy may be caused by: A problem with the ... one of the most common causes of metabolic neuropathies. People who are at the highest risk for ...

  12. Microbial ecology of a novel sulphur cycling consortia from AMD: implications for acid generation

    Science.gov (United States)

    Loiselle, L. M.; Norlund, K. L.; Hitchcock, A. P.; Warren, L. A.

    2009-05-01

    Recent work1 identified a novel microbial consortia consisting of two bacterial strains common to acid mine drainage (AMD) environments (autotrophic sulphur oxidizer Acidithiobacillus ferrooxidans and heterotrophic Acidiphilium spp.) in an environmental enrichment from a mine tailings lake. The two strains showed a specific spatial arrangement within an EPS macrostructure or "pod" allowing linked metabolic redox cycling of sulphur. Sulphur species characterisation of the pods using scanning transmission X-ray microscopy (STXM) indicated that autotrophic tetrathionate disproportionation by A. ferrooxidans producing colloidal elemental sulphur (S0) is coupled to heterotrophic S0 reduction by Acidiphilium spp. Geochemical modelling of the microbial sulphur reactions indicated that if they are widespread in AMD environments, then global AMD-driven CO2 liberation from mineral weathering have been overestimated by 40-90%1. Given the common co-occurrence of these two bacteria in AMD settings, the purpose of this study was to evaluate if these pods could be induced in the laboratory by pure strains and if so, whether their combined sulphur geochemistry mimicked the previous findings. Laboratory batch experiments assessed the development of pods with pure strain type cultures (A. ferrooxidans ATCC 19859 with mixotroph Acidiphilium acidophilum ATCC 738 or strict heterotroph Acp. cryptum ATCC 2158) using fluorescent in situ hybridization (FISH) imaging. The microbial sulphur geochemistry was characterized under autotrophic conditions identical to those used with the environmental AMD enrichment in which the pods were discovered. Results showed that the combined pure strain A. ferrooxidans and Acp. acidophilum form pods identical in structure to the AMD enrichment. To test the hypothesis that these pods form for mutual metabolic benefit, experiments were performed amending pure strain and AMD enrichment bacterial treatments with organic carbon and/or additional sulphur to

  13. Use of sulfur-oxidizing bacteria as recognition elements in hydrogen sulfide biosensing system.

    Science.gov (United States)

    Janfada, Behdokht; Yazdian, Fatemeh; Amoabediny, Ghassem; Rahaie, Mahdi

    2015-01-01

    Four sulfur-oxidizing bacteria (Thiobacillus thioparus, Acidithiobacillus thiooxidans PTCC1717, Acidithiobacillus ferrooxidans PTCC1646, and Acidithiobacillus ferrooxidans PTCC1647) were used as biorecognition elements in a hydrogen sulfide biosensing system. All the experiments were performed in 0.1 M phosphate buffer solution containing 1-20 ppm H2S with optimum pH and temperature for each species. Although H2 S was applied to the biosensing system, the dissolved O2 content decreased. Dissolved O2 consumed by cells in both free and immobilized forms was measured using a dissolved oxygen sensor. Free bacterial cells exhibit fast response (thiooxidans retained more than 50% of activity after 30 days of immobilization. According to the data, A. thiooxidans and A. ferrooxidans are appropriate species for hydrogen sulfide biosensor.

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

    Institute of Scientific and Technical Information of China (English)

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

    2008-01-01

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

  15. Bioleaching of chalcopyrite by pure and mixed culture

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yan-sheng; QIN Wen-qing; WANG Jun; ZHEN Shi-jie; YANG Cong-ren; ZHANG Jian-wen; NAI Shao-shi; QIU Guan-zhou

    2008-01-01

    The bioleaching of chalcopyrite in shake flasks was investigated by using pure Acidithiobacillus ferrooxidans and mixed culture isolated from the acid mine drainage in Yushui and Dabaoshan Copper Mine in China,marked as YS and DB,respectively.The mixed culture consisted mainly of Acidithiobacillus ferrooxidans,Acidithiobacillus thiooxidans,and Leptospirillum spp.(Leptospirillum ferriphilum and Leptospirillum ferrooxians).The results show that the mixed culture is more efficient than the pure Acidithiobacillus ferrooxidans because of the presence of the sulfur-oxidizing cultures that positively increase the dissolution rate and the recovery of copper from chalcopyrite.The pH value decreases with the decrease of chalcopyrite leaching rate,because of the formation of jarosite as a passivation layer on the mineral surface during bioleaching.In the bioleaching using the mixed culture,low pH is got from the sulfur oxidizing inhibiting,the formation of jarosite.The copper extraction reaches 46.27% in mixed culture and 30.37% in pure Acidithiobacillus ferrooxidans after leaching for 75 d.

  16. 嗜酸性氧化硫硫杆菌的分离鉴定及其产酸特性%Isolation, Identification of an Acidithiobacillus Thiooxidan Strain and Its Characteristic of Acid Production

    Institute of Scientific and Technical Information of China (English)

    杨期勇; 邱秀文; 程鹏飞; 李也; 韩金凤; 蒋晟; 单瑶瑶; 孙超

    2015-01-01

    Acidithiobacillus thiooxidan is the major microorganism in bioleaching of heavy metal from sewage sludge. The biological oxidation of sulfur by Acidithiobacillus thiooxidan is the committed step of bioleaching of heavy metal. In order to isolate and cultivate efficientAcidithiobacillus thiooxidan, its characteristic of acid production is studied, and then the method of improving the effect of its acid production is selected. An autotrophic sulfur-oxidizing bacterium (strain JJU-1) was isolated from the activated sludge of a sewage plant. According to its colonial morphology, SEM image of strain, physiological-biochemical properties and its16S rRNA gene sequence analysis, the strain was identified as Acidithiobacillus thiooxidan. Sulfur oxidation by JJU-1 was studied from four aspects, such as initial pH, quantity of sulfur, size of sulfur particle and concentration of surfactant agent (Tween 60). The culture mediums with different initial pH were studied and the results indicated that the initial pH of culture medium almost had no effect on growth ofAcidithiobacillus thiooxidanin later stage, more specifically, the pH of culture mediums were almost the same on the 7th day. The experiment results also showed the growth of microorganism was restrained at pH below 1. Considering the influence by different amount of substrate sulfur added into the culture mediums, the rate of sulfate formation by JJU-1 strain was higher when the sulfur amount increased. On the 8th day the maximum difference of the culture mediums pH with different amount of sulfur was 0.54. The rate of sulfate formation by JJU-1strain increased with the decrease in sulfur particle size. The sulfur particles passing through 180μm yielded lower rates of sulfate formation than these of size below 180μm. The addition of Tween 60 had some effect on sulfate formation by JJU-1 strain. When the concentration of Tween 60 was at 0.4~1.6 g·L-1, it would increase the rate of sulfate formation. However, when the

  17. Environmental transcriptome analysis reveals physiological differences between biofilm and planktonic modes of life of the iron oxidizing bacteria Leptospirillum spp. in their natural microbial community

    OpenAIRE

    Parro Víctor; Arcas Aida; Gómez Manuel J; Moreno-Paz Mercedes

    2010-01-01

    Abstract Background Extreme acidic environments are characterized by their high metal content and lack of nutrients (oligotrophy). Macroscopic biofilms and filaments usually grow on the water-air interface or under the stream attached to solid substrates (streamers). In the Río Tinto (Spain), brown filaments develop under the water stream where the Gram-negative iron-oxidizing bacteria Leptospirillum spp. (L. ferrooxidans and L. ferriphilum) and Acidithiobacillus ferrooxidans are abundant. Th...

  18. Multiple Osmotic Stress Responses in Acidihalobacter prosperus Result in Tolerance to Chloride Ions

    Science.gov (United States)

    Dopson, Mark; Holmes, David S.; Lazcano, Marcelo; McCredden, Timothy J.; Bryan, Christopher G.; Mulroney, Kieran T.; Steuart, Robert; Jackaman, Connie; Watkin, Elizabeth L. J.

    2017-01-01

    Extremely acidophilic microorganisms (pH optima for growth of ≤3) are utilized for the extraction of metals from sulfide minerals in the industrial biotechnology of “biomining.” A long term goal for biomining has been development of microbial consortia able to withstand increased chloride concentrations for use in regions where freshwater is scarce. However, when challenged by elevated salt, acidophiles experience both osmotic stress and an acidification of the cytoplasm due to a collapse of the inside positive membrane potential, leading to an influx of protons. In this study, we tested the ability of the halotolerant acidophile Acidihalobacter prosperus to grow and catalyze sulfide mineral dissolution in elevated concentrations of salt and identified chloride tolerance mechanisms in Ac. prosperus as well as the chloride susceptible species, Acidithiobacillus ferrooxidans. Ac. prosperus had optimum iron oxidation at 20 g L−1 NaCl while At. ferrooxidans iron oxidation was inhibited in the presence of 6 g L−1 NaCl. The tolerance to chloride in Ac. prosperus was consistent with electron microscopy, determination of cell viability, and bioleaching capability. The Ac. prosperus proteomic response to elevated chloride concentrations included the production of osmotic stress regulators that potentially induced production of the compatible solute, ectoine uptake protein, and increased iron oxidation resulting in heightened electron flow to drive proton export by the F0F1 ATPase. In contrast, At. ferrooxidans responded to low levels of Cl− with a generalized stress response, decreased iron oxidation, and an increase in central carbon metabolism. One potential adaptation to high chloride in the Ac. prosperus Rus protein involved in ferrous iron oxidation was an increase in the negativity of the surface potential of Rus Form I (and Form II) that could help explain how it can be active under elevated chloride concentrations. These data have been used to create a

  19. Metabolic Panel

    Science.gov (United States)

    ... basic metabolic panel (BMP) and comprehensive metabolic panel (CMP). The BMP checks your blood sugar, calcium, and ... as creatinine to check your kidney function. The CMP includes all of those tests, as well as ...

  20. Metabolic Disorders

    Science.gov (United States)

    ... as your liver, muscles, and body fat. A metabolic disorder occurs when abnormal chemical reactions in your body ... that produce the energy. You can develop a metabolic disorder when some organs, such as your liver or ...

  1. Metabolic Syndrome

    Science.gov (United States)

    Metabolic syndrome is a group of conditions that put you at risk for heart disease and diabetes. These ... doctors agree on the definition or cause of metabolic syndrome. The cause might be insulin resistance. Insulin is ...

  2. The isolation, identification and characteristics of a sulfur-oxidizing bacterium,Acidithiobacillus thiooxidans%一株嗜酸硫氧化细菌的分离鉴定及生长特性

    Institute of Scientific and Technical Information of China (English)

    王锐; 邱丽娜; 关景洋; 佟莹; 罗佳; 弓爱君; 闫海

    2010-01-01

    从北京清河污泥中分离出一株硫氧化细菌,命名为QH-1,并对该菌株进行了分离鉴定,同时,初步研究了该菌株对几种重金属离子的耐受能力.结果发现,该菌株为革兰氏阴性,短杆状,需氧型,可从氧化还原态的硫元素中获得能量.QH-1菌株具有很好的产酸和耐酸能力,培养24h后pH即可下降到2.0,1周内可达到1.0以下,对数生长期为15d.进入稳定期时pH降为0.6.QH-1菌株的16S rRNA基因测序与分析表明,该菌株与Acidithiobacillus thiooxidans strain AAU具有99%以上的16S rRNA基因序列相似性.通过构建该菌株在相关种属中的系统发育树,并结合形态与生理生化特征分析,将QH-1菌株鉴定为氧化硫嗜酸硫杆菌(Acidithiobacillus thiooxidans).QH-1菌株对Zn~(2+)和Cu~(2+)有一定的耐受性,对Mo~(2+)的耐受性较差.

  3. [Metabolic syndrome].

    Science.gov (United States)

    Mitsuishi, Masanori; Miyashita, Kazutoshi; Itoh, Hiroshi

    2009-02-01

    Metabolic syndrome, which is consisted of hypertension, dyslipidemia and impaired glucose tolerance, is one of the most significant lifestyle-related disorders that lead to cardiovascular diseases. Among many upstream factors that are related to metabolic syndrome, obesity, especially visceral obesity, plays an essential role in its pathogenesis. In recent studies, possible mechanisms which connect obesity to metabolic syndrome have been elucidated, such as inflammation, abnormal secretion of adipokines and mitochondrial dysfunction. In this review, we focus on the relationship between obesity and metabolic syndrome; and illustrate how visceral obesity contributes to, and how the treatments for obesity act on metabolic syndrome.

  4. Nucleotide Metabolism

    DEFF Research Database (Denmark)

    Martinussen, Jan; Willemoës, M.; Kilstrup, Mogens

    2011-01-01

    Metabolic pathways are connected through their utilization of nucleotides as supplier of energy, allosteric effectors, and their role in activation of intermediates. Therefore, any attempt to exploit a given living organism in a biotechnological process will have an impact on nucleotide metabolism....... The aim of this article is to provide knowledge of nucleotide metabolism and its regulation to facilitate interpretation of data arising from genetics, proteomics, and transcriptomics in connection with biotechnological processes and beyond....

  5. Nucleotide Metabolism

    DEFF Research Database (Denmark)

    Martinussen, Jan; Willemoës, M.; Kilstrup, Mogens

    2011-01-01

    Metabolic pathways are connected through their utilization of nucleotides as supplier of energy, allosteric effectors, and their role in activation of intermediates. Therefore, any attempt to exploit a given living organism in a biotechnological process will have an impact on nucleotide metabolism....... The aim of this article is to provide knowledge of nucleotide metabolism and its regulation to facilitate interpretation of data arising from genetics, proteomics, and transcriptomics in connection with biotechnological processes and beyond....

  6. Model-based evaluation of ferrous iron oxidation by acidophilic bacteria in chemostat and biofilm airlift reactors.

    Science.gov (United States)

    Ebrahimi, Sirous; Faraghi, Neda; Hosseini, Maryam

    2015-10-01

    This article presents a model-based evaluation of ferrous iron oxidation in chemostat and biofilm airlift reactors inoculated with a mixed culture of Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans bacteria. The competition between the two types of bacteria in the chemostat and in the biofilm airlift reactors together with the distribution of both bacteria along the biofilm thickness at different time sections has been studied. The bacterial distribution profiles along the biofilm in the airlift reactor at different time scales show that in the beginning A. ferrooxidans bacteria are dominant, but when the reactor operates for a long time the desirable L. ferrooxidans species outcompete A. ferrooxidans as a result of the low Fe(2+) and high Fe(3+) concentrations. The results obtained from the simulation were compared with the experimental data of continuously operated internal loop airlift biofilm reactor. The model results are in good agreement with the experimental results.

  7. Metabolic acidosis.

    Science.gov (United States)

    Lim, Salim

    2007-01-01

    Acute metabolic acidosis is frequently encountered in critically ill patients. Metabolic acidosis can occur as a result of either the accumulation of endogenous acids that consumes bicarbonate (high anion gap metabolic acidosis) or loss of bicarbonate from the gastrointestinal tract or the kidney (hyperchloremic or normal anion gap metabolic acidosis). The cause of high anion gap metabolic acidosis includes lactic acidosis, ketoacidosis, renal failure and intoxication with ethylene glycol, methanol, salicylate and less commonly with pyroglutamic acid (5-oxoproline), propylene glycole or djenkol bean (gjenkolism). The most common causes of hyperchloremic metabolic acidosis are gastrointestinal bicarbonate loss, renal tubular acidosis, drugs-induced hyperkalemia, early renal failure and administration of acids. The appropriate treatment of acute metabolic acidosis, in particular organic form of acidosis such as lactic acidosis, has been very controversial. The only effective treatment for organic acidosis is cessation of acid production via improvement of tissue oxygenation. Treatment of acute organic acidosis with sodium bicarbonate failed to reduce the morbidity and mortality despite improvement in acid-base parameters. Further studies are required to determine the optimal treatment strategies for acute metabolic acidosis.

  8. 极端嗜酸硫杆菌高效筛选、高密度发酵及保藏方法的研究%The study on efficient screening, high-density fermentation and preservation methods for extremely Acidithiobacillus sp.

    Institute of Scientific and Technical Information of China (English)

    冯守帅; 杨海麟; 高凯; 陈金才; 计云鹤; 王武

    2014-01-01

    [目的]针对嗜酸硫杆菌极端特殊的生化特性,分别建立双层平板培养高效筛选方法和补料分批高密度发酵策略,并优选最佳保藏方法,以强化对该类菌种资源的利用和储备效率.[方法]分别采用以异养型微生物Sacchromyces ellipsoideu和Rhodotorula sp.为底层培养物的双层平板培养嗜酸硫杆菌,并结合透射电子显微镜技术(TEM)考察细胞形态差异.结合硫化矿培养基设计及单质硫补料培养策略,延长Acidithiobacillus thiooxidans对数期,提高比生长速率.分析不同保藏方法对嗜酸硫杆菌细胞存活率的影响.[结果]采用异养微生物——Rhodotorula sp.作为底层培养物的双层平板培养法在缩减1/3检出周期的同时将Acidithiobacillus ferrooxidans和Acidithiobacillus thiooxidans的检出率提高了3倍左右.TEM结果表明双层培养中细胞形态更为规则.采用基于Starkey-硫化矿培养基的补料分批发酵策略提高了Acidithiobacillus thiooxidans平均比生长速率,硫对生物量转化率和生产强度分别比分批培养提高31.1%和187.9%.4℃低温保藏方式更适于嗜酸硫杆菌的保藏,有效保藏期1-3月.[结论]Rhodotorula sp.为辅助培养物的双层平板培养法可有效提高嗜酸硫杆菌的筛选效率.设计的Starkey-硫化矿培养基结合补料分批培养策略可实现Acidithiobacillus thiooxidans高密度培养.简单高效的4℃低温保藏方式更适合于嗜酸硫杆菌的中短期保藏.

  9. GenBank blastx search result: AK242773 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242773 J090053L15 AB206839.1 AB206839 Acidithiobacillus ferrooxidans atpI, atpB, atpE, atpF, atpH, atp...A, atpG, atpD, atpC genes for hypothetical protein, a subunit of F1F0-ATP synthase, c s

  10. GenBank blastx search result: AK105071 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK105071 001-045-C11 AB206839.1 Acidithiobacillus ferrooxidans atpI, atpB, atpE, atpF, atpH, atpA, atpG, atp...D, atpC genes for hypothetical protein, a subunit of F1F0-ATP synthase, c subunit o

  11. Microbial aspects of acid mine drainage and its bioremediation

    Institute of Scientific and Technical Information of China (English)

    K.A.NATARAJAN

    2008-01-01

    The role of chemolithotrophs such as Acidithiobacillus ferrooxidans,Acidithiobacillus thiooxidans and Leptospirillum ferrooxidans which were isolated from some abandoned mines and processed waste tailings in the generation of acid mine drainage and toxic metal dissolution was discussed.Mechanisms of acid formation and dissolution of copper,zinc,iron and arsenic from copper,lead-zinc and arsenopyrite-bearing sulfide ores and tailings were established in the presence of Acidithiobacillus group of bacteria.Sulphate Reducing Bacteria(SRB) isolated from the above mine sites could be used to precipitate dissolved metals such as copper,zinc,iron and arsenic.Arsenic bioremediation was demonstrated through the use of native microorganisms such Thiomonas spp.which could oxidize arsenite to arsenate.Bioremoval of arsenic through the use of jarosite precipitates generated by Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans was also found to be very effective.Biotechnological processes hold great promise in the remediation of acid mine drainage and efficient removal of toxic metal ions such as copper,zinc and arsenic.

  12. Implications for global climate change from microbially-produced acid mine drainage

    Science.gov (United States)

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

    2009-05-01

    Microbial catalysis of sulphur cycling in acid mine drainage (AMD) environments is well known but the reaction pathways are poorly characterised. These reaction pathways involve both acid-consuming and acid- generating steps, with important consequences for overall AMD production as well as sulphur and carbon global biogeochemical cycles. Mining-associated sulphuric acid has been implicated in climate change through the weathering of carbonate minerals resulting in the release of 29 Tg C/year as carbon dioxide. Understanding of microbial AMD generation is based predominantly on studies of Acidithiobacillus ferrooxidans despite the knowledge that other environmentally common strains of bacteria are also active sulphur oxidizers and that microbial consortia are likely very important in environmental processes. Using an integrated experimental approach including geochemical experimentation, scanning transmission X-ray microscopy (STXM) and fluorescent in situ hybridization (FISH), we document a novel syntrophic sulphur metabolism involving two common mine bacteria: autotrophic sulphur oxidizing Acidithiobacillus ferrooxidans and heterotrophic Acidiphilium spp. The proposed sulphur geochemistry associated with this bacterial consortium produces 40-90% less acid than expected based on abiotic AMD models, with significant implications for both AMD mitigation and AMD carbon flux modelling. The two bacterial strains are specifically spatially segregated within a macrostructure of extracellular polymeric substance (EPS) that provides the necessary microgeochemical conditions for coupled sulphur oxidation and reduction reactions. STXM results identify multiple sulphur oxidation states associated with the pods, indicating that they are the sites of active sulphur disproportionation and recycling. Recent laboratory experimentation using type culture strains of the bacteria involved in pod-formation suggesting that this phenomenon is likely to be widespread in environments

  13. Metabolic encephalopathies.

    Science.gov (United States)

    Angel, Michael J; Young, G Bryan

    2011-11-01

    Kinnier Wilson coined the term metabolic encephalopathy to describe a clinical state of global cerebral dysfunction induced by systemic stress that can vary in clinical presentation from mild executive dysfunction to deep coma with decerebrate posturing; the causes are numerous. Some mechanisms by which cerebral dysfunction occurs in metabolic encephalopathies include focal or global cerebral edema, alterations in transmitter function, the accumulation of uncleared toxic metabolites, postcapillary venule vasogenic edema, and energy failure. This article focuses on common causes of metabolic encephalopathy, and reviews common causes, clinical presentations and, where relevant, management.

  14. Structure/function relationship of the rusticyanin among thiobacillus ferroxidans: from the fermenter to the crystal; Relations structure/fonction de la rusticyanine chez thiobacillus ferrooxidans: du fermenteur au cristal

    Energy Technology Data Exchange (ETDEWEB)

    Nunzi, F.

    1996-09-23

    The commercial extraction of copper and uranium from ores by microbial leaching turns to account the iron oxidation capacity of Thiobacillus ferroxidans. The iron oxidation involves an electron transport chain localized in the peri-plasmic space of the cell. The aim of our work is to study the structure-function relationships of rusticyanin, the most important component of this respiratory chain. Rusticyanin is a blue copper protein and has been characterized from a new strain of Thilbacillus ferrooxidans. A preliminary electrochemical study has been made with a new modified-gold electrode and we have examined, in particular, the pH dependence of the high redox potential of rusticyanin. Its amino acid sequence has been determined and a comparison with two other rusticyanin sequences, isolated from different strains, shows a high degree of homology. A structural alignment with six other blue copper proteins allows to propose four residues as copper ligands, His 84, Cys 138, His 143 and Met 148. The supposed factors responsible for the high redox potential of rusticyanin are discussed. (author)

  15. Metabolic Syndrome

    Science.gov (United States)

    ... hypertension, hypertriglyceridemia, insulin resistance syndrome, low HDL cholesterol, Metabolic Syndrome, overweight, syndrome x, type 2 diabetes Family Health, Kids and Teens, Men, Women January 2005 Copyright © American Academy of Family PhysiciansThis ...

  16. Metabolic syndrome

    Directory of Open Access Journals (Sweden)

    Gogia Atul

    2006-02-01

    Full Text Available The Metabolic syndrome is a widely prevalent and multi-factorial disorder. The syndrome has been given several names, including- the metabolic syndrome, the insulin resistance syndrome, the plurimetabolic syndrome, and the deadly quartet. With the formulation of NCEP/ATP III guidelines, some uniformity and standardization has occurred in the definition of metabolic syndrome and has been very useful for epidemiological purposes. The mechanisms underlying the metabolic syndrome are not fully known; however resistance to insulin stimulated glucose uptake seems to modify biochemical responses in a way that predisposes to metabolic risk factors. The clinical relevance of the metabolic syndrome is related to its role in the development of cardiovascular disease. Management of the metabolic syndrome involves patient-education and intervention at various levels. Weight reduction is one of the main stays of treatment. In this article we comprehensively discuss this syndrome- the epidemiology, pathogenesis, clinical relevance and management. The need to do a comprehensive review of this particular syndrome has arisen in view of the ever increasing incidence of this entitiy. Soon, metabolic syndrome will overtake cigarette smoking as the number one risk factor for heart disease among the US population. Hardly any issue of any primary care medical journal can be opened without encountering an article on type 2 diabetes, dyslipidemia or hypertension. It is rare to see type 2 diabetes, dyslipidemia, obesity or hypertension in isolation. Insulin resistance and resulting hyperinsulinemia have been implicated in the development of glucose intolerance (and progression to type 2 diabetes, hypertriglyceridemia, hypertension, polycystic ovary yndrome, hypercoagulability and vascular inflammation, as well as the eventual development of atherosclerotic cardiovascular disease manifested as myocardial infarction, stroke and myriad end organ diseases. Conversely

  17. Lipid Metabolism

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    2008393 Effects of angiotensin Ⅱ type 1 receptor blocker on triglyceride metabolism in the liver: experiment with Zucker fatty rats. RAN Jianmin(冉建民), et al. Dept Endocrinol, Guangzhou Red Cross Hosp, 4th Hosp Med Coll, Jinan Univ, Guangzhou 510220. Natl Med J China 2008;88(22):1557-1561. Objective To investigate the effects of angiotensin receptor blocker (ARB) on triglyceride (TG) metabolism and mechanism thereof.

  18. Bacterial consortium for copper extraction from sulphide ore consisting mainly of chalcopyrite.

    Science.gov (United States)

    Romo, E; Weinacker, D F; Zepeda, A B; Figueroa, C A; Chavez-Crooker, P; Farias, J G

    2013-01-01

    The mining industry is looking forward for bacterial consortia for economic extraction of copper from low-grade ores. The main objective was to determine an optimal bacterial consortium from several bacterial strains to obtain copper from the leach of chalcopyrite. The major native bacterial species involved in the bioleaching of sulphide ore (Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, Leptospirillum ferrooxidans and Leptospirillum ferriphilum) were isolated and the assays were performed with individual bacteria and in combination with At. thiooxidans. In conclusion, it was found that the consortium integrated by At. ferrooxidans and At. thiooxidans removed 70% of copper in 35 days from the selected ore, showing significant differences with the other consortia, which removed only 35% of copper in 35 days. To validate the assays was done an escalation in columns, where the bacterial consortium achieved a higher percentage of copper extraction regarding to control.

  19. Bacterial consortium for copper extraction from sulphide ore consisting mainly of chalcopyrite

    Directory of Open Access Journals (Sweden)

    E. Romo

    2013-01-01

    Full Text Available The mining industry is looking forward for bacterial consortia for economic extraction of copper from low-grade ores. The main objective was to determine an optimal bacterial consortium from several bacterial strains to obtain copper from the leach of chalcopyrite. The major native bacterial species involved in the bioleaching of sulphide ore (Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, Leptospirillum ferrooxidans and Leptospirillum ferriphilum were isolated and the assays were performed with individual bacteria and in combination with At. thiooxidans. In conclusion, it was found that the consortium integrated by At. ferrooxidans and At. thiooxidans removed 70% of copper in 35 days from the selected ore, showing significant differences with the other consortia, which removed only 35% of copper in 35 days. To validate the assays was done an escalation in columns, where the bacterial consortium achieved a higher percentage of copper extraction regarding to control.

  20. Bacterial consortium for copper extraction from sulphide ore consisting mainly of chalcopyrite

    Science.gov (United States)

    Romo, E.; Weinacker, D.F.; Zepeda, A.B.; Figueroa, C.A.; Chavez-Crooker, P.; Farias, J.G.

    2013-01-01

    The mining industry is looking forward for bacterial consortia for economic extraction of copper from low-grade ores. The main objective was to determine an optimal bacterial consortium from several bacterial strains to obtain copper from the leach of chalcopyrite. The major native bacterial species involved in the bioleaching of sulphide ore (Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, Leptospirillum ferrooxidans and Leptospirillum ferriphilum) were isolated and the assays were performed with individual bacteria and in combination with At. thiooxidans. In conclusion, it was found that the consortium integrated by At. ferrooxidans and At. thiooxidans removed 70% of copper in 35 days from the selected ore, showing significant differences with the other consortia, which removed only 35% of copper in 35 days. To validate the assays was done an escalation in columns, where the bacterial consortium achieved a higher percentage of copper extraction regarding to control. PMID:24294251

  1. Insights to the effects of free cells on community structure of attached cells and chalcopyrite bioleaching during different stages.

    Science.gov (United States)

    Feng, Shoushuai; Yang, Hailin; Wang, Wu

    2016-01-01

    The effects of free cells on community structure of attached cells and chalcopyrite bioleaching by Acidithiobacillus sp. during different stages were investigated. The attached cells of Acidithiobacillus thiooxidans owned the community advantage from 14thd to the end of bioprocess in the normal system. The community structure of attached cells was greatly influenced in the free cells-deficient systems. Compared to A. thiooxidans, the attached cells community of Acidithiobacillus ferrooxidans had a higher dependence on its free cells. Meanwhile, the analysis of key biochemical parameters revealed that the effects of free cells on chalcopyrite bioleaching in different stages were diverse, ranging from 32.8% to 64.3%. The bioleaching contribution of free cells of A. ferrooxidans in the stationary stage (8-14thd) was higher than those of A. thiooxidans, while the situation was gradually reversed in the jarosite passivation inhibited stage (26-40thd). These results may be useful in guiding chalcopyrite bioleaching.

  2. Metabolic Syndrome (For Parents)

    Science.gov (United States)

    ... Old Feeding Your 1- to 2-Year-Old Metabolic Syndrome KidsHealth > For Parents > Metabolic Syndrome A A A ... this is a condition called metabolic syndrome . About Metabolic Syndrome Not to be confused with metabolic disease (which ...

  3. Metabolic syndrome

    Institute of Scientific and Technical Information of China (English)

    Charles Shaeffer

    2004-01-01

    @@ The emergence of cardiac disease as the number one world-wide cause of death justifies efforts to identify individuals at higher risk for preventive therapy. The metabolic syndrome, originally described by Reaven, 1 has been associated with higher cardiovascular disease risk. 2 Type Ⅱ diabetes is also a frequent sequela. 3

  4. 两种硫杆菌对河涌底泥重金属的生物沥滤%Bioleaching of heavy metals from brooklet sediment by Thiobacillus ferrooxidans and Thiobacillus thiooxidans

    Institute of Scientific and Technical Information of China (English)

    张再利; 贾晓珊

    2008-01-01

    自矿山酸性废水中分离纯化得到氧化亚铁硫杆菌(Thiobacillus ferrooxidans,T.f)与氧化硫硫杆菌(Thiobacillus thiooxidans,T.t),利用这2种硫杆菌对广州郭村河涌底泥中Cd、Cr、Pb、Ni、Cu和Zn 6种重金属进行序批式生物沥滤试验.结果表明,T.f菌对重金属的浸出能力高于T.t菌.对Cd、Cr、Ni、Cu和Zn的浸出率Y.f菌最高可达60%、45%、70%、90%和75%,T.t菌则分别为45%、34%、50%、65%和55%.二者对Pb的去除率相当,均在25%左右.向T.f菌分别提供S粉与Fe2+,2种底物对Cd、Ni、Cu和Zn的浸出效果无明显影响,而对Cr和Pb的浸出,投加S粉的浸出效果更好.同时向T.f菌投加S粉与Fe2+2种底物,其浸出效果反而下降.可能是T.f菌代谢生成的SO42与Fe3+易生成黄铁矾等沉淀物质,与溶出的重金属发生共沉淀,从而降低其浸出效果.

  5. Metabolic Syndrome

    Directory of Open Access Journals (Sweden)

    Sevil Ikinci

    2010-10-01

    Full Text Available Metabolic Syndrome is a combination of risk factors including common etiopathogenesis. These risk factors play different roles in occurence of atherosclerotic diseases, type 2 diabetes, and cancers. Although a compromise can not be achieved on differential diagnosis for MS, the existence of any three criterias enable to diagnose MS. These are abdominal obesity, dislipidemia (hypertrigliceridemia, hypercholesterolemia, and reduced high density lipoprotein hypertension, and elevated fasting blood glucose. According to the results of Metabolic Syndrome Research (METSAR, the overall prevalence of MS in Turkey is 34%; in females 40%, and in males it is 28%. As a result of “Western” diet, and increased frequency of obesity, MS is observed in children and in adolescents both in the world and in Turkey. Resulting in chronic diseases, it is thought that the syndrome can be prevented by healthy lifestyle behaviours. [TAF Prev Med Bull 2010; 9(5.000: 535-540

  6. What is Metabolic Syndrome?

    Science.gov (United States)

    ... from the NHLBI on Twitter. What Is Metabolic Syndrome? Metabolic syndrome is the name for a group of ... that may play a role in causing metabolic syndrome. Outlook Metabolic syndrome is becoming more common due to a ...

  7. 氧化硫硫杆菌TS6的生长条件及其对重金属耐受性研究%Optimum growth condition of Acidithiobacillus thiooxidans TS6 and its resistance to heavy metals

    Institute of Scientific and Technical Information of China (English)

    黄峰源; 王世梅; 周立祥

    2006-01-01

    采用纯培养的方法研究了温度和介质起始pH以及重金属对嗜酸性氧化硫硫杆菌(Acidithiobacillus thiooxidans TS6)菌株生长与活性的影响.研究表明,菌株TS6的最适生长温度为28℃,最适起始生长pH范围为2.0~6.0.在上述条件下,TS6旺盛生长,表现出氧化硫能力最强.通过检测TS6对几种重金属(Cr3+、Cu2+、Zn2+、Ni2+)的耐受性,结果发现TS6对上述重金属均有较强的耐受性,至少可耐受Cr3+、Cu2+、Zn2+、Ni2+的浓度分别达1500、400、1000和250mg·L-1.在相同的浓度下,不同重金属对TS6生长产酸作用的影响由小到大依次为Cr3+、Zn2+、Cu2+、Ni2+.随着TS6菌株驯化时间的延长,它们对重金属的耐受性可望得到进一步的增强,完全满足对各种污水污泥进行生物淋滤处理的条件.

  8. Insights into the structure and metabolic function of microbes that shape pelagic iron-rich aggregates ("iron snow").

    Science.gov (United States)

    Lu, Shipeng; Chourey, Karuna; Reiche, Marco; Nietzsche, Sandor; Shah, Manesh B; Neu, Thomas R; Hettich, Robert L; Küsel, Kirsten

    2013-07-01

    Microbial ferrous iron [Fe(II)] oxidation leads to the formation of iron-rich macroscopic aggregates ("iron snow") at the redoxcline in a stratified lignite mine lake in east-central Germany. We aimed to identify the abundant Fe-oxidizing and Fe-reducing microorganisms likely to be involved in the formation and transformation of iron snow present in the redoxcline in two basins of the lake that differ in their pH values. Nucleic acid- and lipid-stained microbial cells of various morphologies detected by confocal laser scanning microscopy were homogeneously distributed in all iron snow samples. The dominant iron mineral appeared to be schwertmannite, with shorter needles in the northern than in the central basin samples. Total bacterial 16S rRNA gene copies ranged from 5.0 × 10(8) copies g (dry weight)(-1) in the acidic central lake basin (pH 3.3) to 4.0 × 10(10) copies g (dry weight)(-1) in the less acidic (pH 5.9) northern basin. Total RNA-based quantitative PCR assigned up to 61% of metabolically active microbial communities to Fe-oxidizing- and Fe-reducing-related bacteria, indicating that iron metabolism was an important metabolic strategy. Molecular identification of abundant groups suggested that iron snow surfaces were formed by chemoautotrophic iron oxidizers, such as Acidimicrobium, Ferrovum, Acidithiobacillus, Thiobacillus, and Chlorobium, in the redoxcline and were rapidly colonized by heterotrophic iron reducers, such as Acidiphilium, Albidiferax-like, and Geobacter-like groups. Metaproteomics yielded 283 different proteins from northern basin iron snow samples, and protein identification provided a glimpse into some of their in situ metabolic processes, such as primary production (CO2 fixation), respiration, motility, and survival strategies.

  9. Insights into the Structure and Metabolic Function of Microbes That Shape Pelagic Iron-Rich Aggregates (“Iron Snow”)

    Science.gov (United States)

    Lu, Shipeng; Chourey, Karuna; Reiche, Marco; Nietzsche, Sandor; Shah, Manesh B.; Neu, Thomas R.; Hettich, Robert L.

    2013-01-01

    Microbial ferrous iron [Fe(II)] oxidation leads to the formation of iron-rich macroscopic aggregates (“iron snow”) at the redoxcline in a stratified lignite mine lake in east-central Germany. We aimed to identify the abundant Fe-oxidizing and Fe-reducing microorganisms likely to be involved in the formation and transformation of iron snow present in the redoxcline in two basins of the lake that differ in their pH values. Nucleic acid- and lipid-stained microbial cells of various morphologies detected by confocal laser scanning microscopy were homogeneously distributed in all iron snow samples. The dominant iron mineral appeared to be schwertmannite, with shorter needles in the northern than in the central basin samples. Total bacterial 16S rRNA gene copies ranged from 5.0 × 108 copies g (dry weight)−1 in the acidic central lake basin (pH 3.3) to 4.0 × 1010 copies g (dry weight)−1 in the less acidic (pH 5.9) northern basin. Total RNA-based quantitative PCR assigned up to 61% of metabolically active microbial communities to Fe-oxidizing- and Fe-reducing-related bacteria, indicating that iron metabolism was an important metabolic strategy. Molecular identification of abundant groups suggested that iron snow surfaces were formed by chemoautotrophic iron oxidizers, such as Acidimicrobium, Ferrovum, Acidithiobacillus, Thiobacillus, and Chlorobium, in the redoxcline and were rapidly colonized by heterotrophic iron reducers, such as Acidiphilium, Albidiferax-like, and Geobacter-like groups. Metaproteomics yielded 283 different proteins from northern basin iron snow samples, and protein identification provided a glimpse into some of their in situ metabolic processes, such as primary production (CO2 fixation), respiration, motility, and survival strategies. PMID:23645202

  10. Isolation and Identifaction of Acidithiobacillus thiooxidans with Strong Phosphorous Ore Bioleaching Ability%一株高浸磷嗜酸氧化硫硫杆菌的分离与鉴定

    Institute of Scientific and Technical Information of China (English)

    吕早生; 关海燕; 李凌凌; 贾伟伟

    2011-01-01

    从矿山土样中分离到一株嗜酸的浸磷矿细菌HY-01,观察其形态并研究其培养特征.结果显示,该菌株为革兰氏阴性、短杆状运动细菌,菌体长1~2μm,宽0.5~0.7 μm,能在pH 1.5~8.0的范围内生长,最适生长温度为37℃,最适pH为1.5~3.0.该菌株可以KNO3、NH4NO3、(NH4)2CO3、NH4H2PO4、(NH4)2SO4以及蛋白胨为氮源,以元素硫和黄铁矿中的硫为能源,不能利用有机物质以及硫代硫酸钠、硫酸亚铁等无机物为能源生长.形态、生理生化特性研究以及16SrDNA序列分析表明,该菌株为嗜酸氧化硫硫杆菌.浸矿实验结果表明其具有很高的磷矿浸出能力.图6表1参18%Acidophilic sulfur-oxidizing bacterium HY-01 was isolated from mine soil. Strain HY-01 was motile, gram-negative, rod-shaped and 0.5 to 0.7 μm x 1 to 2 um in size. The strain grew optimally with initial pH 2.0-2.5 and temperature 37 °C. It could grow with potassium nitrate, ammonium nitrate, ammonirm carbonate, ammonium dihydrogen phosphate, ammonium sulfate and tryptone as nitrogen sources. It could use elemental sulfur and pyrite as energy sources, but not organic minerals and inorganic minerals, including sodium thiosulfate and ferrous sulfate. The morphological, biochemical and physiological characteristics of the strain and the analysis based on 16S rDNA gene sequence indicated that strain HY-01 was most closely related to Acidithiobacillus thiooxidans. The sulfur-oxidizing bacteria could positively increase the dissolution rate and percentage of phosphorus recovery from phosphate ore. Fig 6, Tab 1, Ref 18

  11. 三株氧化硫硫杆菌的分离与鉴定%Isolation and Characterization of three strains of Acidithiobacillus thiooxidans and its bioleaching of chalcopyrite

    Institute of Scientific and Technical Information of China (English)

    符波; 周洪波; 张倩; 邱冠周

    2008-01-01

    Three strains of mesophilic and acidophilic sulfur-oxidizing bacteria were isolated from coal heap drainage. The bacteria are motile, Gram-negative, rod-shaped, and measures 0.4 to 0.7 by 1 to 2 μm. They grow optimally at 30 ℃ and initial pH 2.0~2.5. The strains grow autotrophically by using elemental sulfur, sodium thiosulfate and potassium tetrathionate as energy sources. The strains can not use organic matter and inorganic minerals including ferrous sulfate, pyrite and chalcopyrite as energy sources. The morphological, biochemical and physiological characterization and analysis based on 16S rRNA gene sequence indicated that the strains are most closely related to Acidithiobacillus thiooxidans (>99% similarity in gene sequence). The presence of sulfur-oxidizing bacteria positively increased the dissolution rate and the percentage recovery of copper from chalcopyrite by producing acid.%从煤堆废水中分离得到3株嗜温嗜酸硫氧化细菌.这3株菌株为革兰氏阴性、菌体大小0.4~0.7 μm×1~2 μm、短杆状运动细菌,其最适生长温度为 30 ℃和最适生长pH 2.0~2.5.它们能够利用元素硫,硫代硫酸钠和连四硫酸钾为能源进行自养生长,不能利用有机物质以及硫酸亚铁、黄铁矿和黄铜矿等无机物质作为能源生长.细菌的形态、生理生化特性研究以及基于16S rRNA序列同源性构建的系统发育树结果表明,这3株细菌初步鉴定为氧化硫硫杆菌.氧化硫硫杆菌能够通过产酸有效促进黄铜矿的浸出速率和浸出率.

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

    Science.gov (United States)

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

    2012-12-01

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

  13. Carbohydrate Metabolism Disorders

    Science.gov (United States)

    ... you eat. Food is made up of proteins, carbohydrates, and fats. Chemicals in your digestive system (enzymes) ... metabolic disorder, something goes wrong with this process. Carbohydrate metabolism disorders are a group of metabolic disorders. ...

  14. Production of Glycolic Acid by Chemolithotrophic Iron- and Sulfur-Oxidizing Bacteria and Its Role in Delineating and Sustaining Acidophilic Sulfide Mineral-Oxidizing Consortia▿

    Science.gov (United States)

    Ñancucheo, Ivan; Johnson, D. Barrie

    2010-01-01

    Glycolic acid was detected as an exudate in actively growing cultures of three chemolithotrophic acidophiles that are important in biomining operations, Leptospirillum ferriphilum, Acidithiobacillus (At.) ferrooxidans, and At. caldus. Although similar concentrations of glycolic acid were found in all cases, the concentrations corresponded to ca. 24% of the total dissolved organic carbon (DOC) in cultures of L. ferriphilum but only ca. 5% of the total DOC in cultures of the two Acidithiobacillus spp. Rapid acidification (to pH 1.0) of the culture medium of At. caldus resulted in a large increase in the level of DOC, although the concentration of glycolic acid did not change in proportion. The archaeon Ferroplasma acidiphilum grew in the cell-free spent medium of At. caldus; glycolic acid was not metabolized, although other unidentified compounds in the DOC pool were metabolized. Glycolic acid exhibited levels of toxicity with 21 strains of acidophiles screened similar to those of acetic acid. The most sensitive species were chemolithotrophs (L. ferriphilum and At. ferrivorans), while the most tolerant species were chemoorganotrophs (Acidocella, Acidobacterium, and Ferroplasma species), and the ability to metabolize glycolic acid appeared to be restricted (among acidophiles) to Firmicutes (chiefly Sulfobacillus spp.). Results of this study help explain why Sulfobacillus spp. rather than other acidophiles are the main organic carbon-degrading bacteria in continuously fed stirred tanks used to bioprocess sulfide mineral concentrates and also why temporary cessation of pH control in these systems, resulting in rapid acidification, often results in a plume of the archaeon Ferroplasma. PMID:19933342

  15. Production of glycolic acid by chemolithotrophic iron- and sulfur-oxidizing bacteria and its role in delineating and sustaining acidophilic sulfide mineral-oxidizing consortia.

    Science.gov (United States)

    Nancucheo, Ivan; Johnson, D Barrie

    2010-01-01

    Glycolic acid was detected as an exudate in actively growing cultures of three chemolithotrophic acidophiles that are important in biomining operations, Leptospirillum ferriphilum, Acidithiobacillus (At.) ferrooxidans, and At. caldus. Although similar concentrations of glycolic acid were found in all cases, the concentrations corresponded to ca. 24% of the total dissolved organic carbon (DOC) in cultures of L. ferriphilum but only ca. 5% of the total DOC in cultures of the two Acidithiobacillus spp. Rapid acidification (to pH 1.0) of the culture medium of At. caldus resulted in a large increase in the level of DOC, although the concentration of glycolic acid did not change in proportion. The archaeon Ferroplasma acidiphilum grew in the cell-free spent medium of At. caldus; glycolic acid was not metabolized, although other unidentified compounds in the DOC pool were metabolized. Glycolic acid exhibited levels of toxicity with 21 strains of acidophiles screened similar to those of acetic acid. The most sensitive species were chemolithotrophs (L. ferriphilum and At. ferrivorans), while the most tolerant species were chemoorganotrophs (Acidocella, Acidobacterium, and Ferroplasma species), and the ability to metabolize glycolic acid appeared to be restricted (among acidophiles) to Firmicutes (chiefly Sulfobacillus spp.). Results of this study help explain why Sulfobacillus spp. rather than other acidophiles are the main organic carbon-degrading bacteria in continuously fed stirred tanks used to bioprocess sulfide mineral concentrates and also why temporary cessation of pH control in these systems, resulting in rapid acidification, often results in a plume of the archaeon Ferroplasma.

  16. Cancer stem cell metabolism

    National Research Council Canada - National Science Library

    Peiris-Pagès, Maria; Martinez-Outschoorn, Ubaldo E; Pestell, Richard G; Sotgia, Federica; Lisanti, Michael P

    2016-01-01

    .... Cancer stem cells also seem to adapt their metabolism to microenvironmental changes by conveniently shifting energy production from one pathway to another, or by acquiring intermediate metabolic phenotypes...

  17. Estudo da dissolução oxidativa microbiológica de uma complexa amostra mineral contendo pirita (FeS2, Pirrotita (Fe1-xS e Molibdenita (MoS2 Microbiological oxidative dissolution of a complex mineral sample containing pyrite (FeS2, pyrrotite (Fe1-xS and molybdenite (MoS2

    Directory of Open Access Journals (Sweden)

    Wilmo E. Francisco Jr

    2007-10-01

    Full Text Available This work aims to study the oxidation of a complex molybdenite mineral which contains pyrite and pyrrotite, by Acidithiobacillus ferrooxidans. This study was performed by respirometric essays and bioleaching in shake flasks. Respirometric essays yielded the kinetics of mineral oxidation. The findings showed that sulfide oxidation followed classical Michaelis-Menten kinetics. Bioleaching in shake flasks allowed evaluation of chemical and mineralogical changes resulting from sulfide oxidation. The results demonstrated that pyrrotite and pyrite were completely oxidized in A. ferrooxidans cultures whereas molybdenite was not consumed. These data indicated that molybdenite was the most recalcitrant sulfide in the sample.

  18. Environmental transcriptome analysis reveals physiological differences between biofilm and planktonic modes of life of the iron oxidizing bacteria Leptospirillum spp. in their natural microbial community

    Directory of Open Access Journals (Sweden)

    Parro Víctor

    2010-06-01

    Full Text Available Abstract Background Extreme acidic environments are characterized by their high metal content and lack of nutrients (oligotrophy. Macroscopic biofilms and filaments usually grow on the water-air interface or under the stream attached to solid substrates (streamers. In the Río Tinto (Spain, brown filaments develop under the water stream where the Gram-negative iron-oxidizing bacteria Leptospirillum spp. (L. ferrooxidans and L. ferriphilum and Acidithiobacillus ferrooxidans are abundant. These microorganisms play a critical role in bioleaching processes for industrial (biominery and environmental applications (acid mine drainage, bioremediation. The aim of this study was to investigate the physiological differences between the free living (planktonic and the sessile (biofilm associated lifestyles of Leptospirillum spp. as part of its natural extremely acidophilic community. Results Total RNA extracted from environmental samples was used to determine the composition of the metabolically active members of the microbial community and then to compare the biofilm and planktonic environmental transcriptomes by hybridizing to a genomic microarray of L. ferrooxidans. Genes up-regulated in the filamentous biofilm are involved in cellular functions related to biofilm formation and maintenance, such as: motility and quorum sensing (mqsR, cheAY, fliA, motAB, synthesis of cell wall structures (lnt, murA, murB, specific proteases (clpX/clpP, stress response chaperons (clpB, clpC, grpE-dnaKJ, groESL, etc. Additionally, genes involved in mixed acid fermentation (poxB, ackA were up-regulated in the biofilm. This result, together with the presence of small organic acids like acetate and formate (1.36 mM and 0.06 mM respectively in the acidic (pH 1.8 water stream, suggests that either L. ferrooxidans or other member of the microbial community are producing acetate in the acidophilic biofilm under microaerophilic conditions. Conclusions Our results indicate that the

  19. Profiling metabolic networks to study cancer metabolism.

    Science.gov (United States)

    Hiller, Karsten; Metallo, Christian M

    2013-02-01

    Cancer is a disease of unregulated cell growth and survival, and tumors reprogram biochemical pathways to aid these processes. New capabilities in the computational and bioanalytical characterization of metabolism have now emerged, facilitating the identification of unique metabolic dependencies that arise in specific cancers. By understanding the metabolic phenotype of cancers as a function of their oncogenic profiles, metabolic engineering may be applied to design synthetically lethal therapies for some tumors. This process begins with accurate measurement of metabolic fluxes. Here we review advanced methods of quantifying pathway activity and highlight specific examples where these approaches have uncovered potential opportunities for therapeutic intervention.

  20. Metabolism disrupting chemicals and metabolic disorders.

    Science.gov (United States)

    Heindel, Jerrold J; Blumberg, Bruce; Cave, Mathew; Machtinger, Ronit; Mantovani, Alberto; Mendez, Michelle A; Nadal, Angel; Palanza, Paola; Panzica, Giancarlo; Sargis, Robert; Vandenberg, Laura N; Vom Saal, Frederick

    2017-03-01

    The recent epidemics of metabolic diseases, obesity, type 2 diabetes(T2D), liver lipid disorders and metabolic syndrome have largely been attributed to genetic background and changes in diet, exercise and aging. However, there is now considerable evidence that other environmental factors may contribute to the rapid increase in the incidence of these metabolic diseases. This review will examine changes to the incidence of obesity, T2D and non-alcoholic fatty liver disease (NAFLD), the contribution of genetics to these disorders and describe the role of the endocrine system in these metabolic disorders. It will then specifically focus on the role of endocrine disrupting chemicals (EDCs) in the etiology of obesity, T2D and NAFLD while finally integrating the information on EDCs on multiple metabolic disorders that could lead to metabolic syndrome. We will specifically examine evidence linking EDC exposures during critical periods of development with metabolic diseases that manifest later in life and across generations.

  1. Cross-Comparison of Leaching Strains Isolated from Two Different Regions: Chambishi and Dexing Copper Mines

    Directory of Open Access Journals (Sweden)

    Baba Ngom

    2014-01-01

    Full Text Available A cross-comparison of six strains isolated from two different regions, Chambishi copper mine (Zambia, Africa and Dexing copper mine (China, Asia, was conducted to study the leaching efficiency of low grade copper ores. The strains belong to the three major species often encountered in bioleaching of copper sulfide ores under mesophilic conditions: Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, and Leptospirillum ferriphilum. Prior to their study in bioleaching, the different strains were characterized and compared at physiological level. The results revealed that, except for copper tolerance, strains within species presented almost similar physiological traits with slight advantages of Chambishi strains. However, in terms of leaching efficiency, native strains always achieved higher cell density and greater iron and copper extraction rates than the foreign microorganisms. In addition, microbial community analysis revealed that the different mixed cultures shared almost the same profile, and At. ferrooxidans strains always outcompeted the other strains.

  2. Repetitive sequence based polymerase chain reaction to differentiate close bacteria strains in acidic sites

    Institute of Scientific and Technical Information of China (English)

    XIE Ming; YIN Hua-qun; LIU Yi; LIU Jie; LIU Xue-duan

    2008-01-01

    To study the diversity of bacteria strains newly isolated from several acid mine drainage(AMD) sites in China,repetitive sequence based polymerase chain reaction (rep-PCR),a well established technology for diversity analysis of closely related bacteria strains,was conducted on 30 strains of bacteria Leptospirillum ferriphilium,8 strains of bacteria Acidithiobacillus ferrooxidans,as well as the Acidithiobacillus ferrooxidans type strain ATCC (American Type Culture Collection) 23270.The results showed that,using ERIC and BOX primer sets,rep-PCR produced highly discriminatory banding patterns.Phylogenetic analysis based on ERIC-PCR banding types was made and the results indicated that rep-PCR could be used as a rapid and highly discriminatory screening technique in studying bacterial diversity,especially in differentiating bacteria within one species in AMD.

  3. Effect of Cu2+ ions on bioleaching of marmatite

    Institute of Scientific and Technical Information of China (English)

    CHEN Song; QIN Wen-qing; QIU Guan-zhou

    2008-01-01

    The effect of Cu2+ ions on bioleaching of marmatite was investigated through shake leaching experiments.The bacteria inoculated are a mixed culture of Acidithiobacillus ferrooxidans,Acidithiobacillus thiooxidans and Lepthospirillum ferrooxidans.The results show that zinc is selectively leached,and the addition of appropriate content of Cu2+ ions has positive effect on the bioleaching of marmatite.SEM and EDX analyses of the leaching residue reveal that a product layer composed of iron sulfide,elemental sulfur and jarosite forms on the mineral surface.The biooxidation of elemental sulfur is catalyzed by the Cu2+ ions,which eliminate the barrier to bioleaching of marmatite and keep low pH value.With the addition of 0.5 g/L Cu2+ ions,the maximum zinc extraction rate reaches 73% after 23 d at the temperature of 30 ℃ with the pulp density of 10%,while that of iron is only about 10%.

  4. Influence Of Used Bacterial Culture On Zinc And Aluminium Bioleaching From Printed Circuit Boards

    Directory of Open Access Journals (Sweden)

    Mrazikova Anna

    2015-06-01

    Full Text Available Bioleaching processes were used to solubilize metals (Cu, Ni, Zn and Al from printed circuit boards (PCBs. In this study, a PCBs-adapted pure culture of Acidithiobacillus ferrooxidans, pure culture of Acidithiobacillus thiooxidans and PCBs-adapted mixed culture of A. ferrooxidans and A. thiooxidans were used for recovery of the metals. The study showed that the mixed bacterial culture has the greatest potential to dissolve metals. The maximum metal bioleaching efficiencies were found to be 100, 92, 89 and 20% of Cu, Ni, Zn and Al, respectively. The mixed culture revealed higher bacterial stability. The main factor responsible for high metal recovery was the ability of the mixed culture to maintain the low pH during the whole process. The pure culture of A. thiooxidans had no significant effect on metal bioleaching from PCBs.

  5. Cross-comparison of leaching strains isolated from two different regions: Chambishi and Dexing copper mines.

    Science.gov (United States)

    Ngom, Baba; Liang, Yili; Liu, Xueduan

    2014-01-01

    A cross-comparison of six strains isolated from two different regions, Chambishi copper mine (Zambia, Africa) and Dexing copper mine (China, Asia), was conducted to study the leaching efficiency of low grade copper ores. The strains belong to the three major species often encountered in bioleaching of copper sulfide ores under mesophilic conditions: Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, and Leptospirillum ferriphilum. Prior to their study in bioleaching, the different strains were characterized and compared at physiological level. The results revealed that, except for copper tolerance, strains within species presented almost similar physiological traits with slight advantages of Chambishi strains. However, in terms of leaching efficiency, native strains always achieved higher cell density and greater iron and copper extraction rates than the foreign microorganisms. In addition, microbial community analysis revealed that the different mixed cultures shared almost the same profile, and At. ferrooxidans strains always outcompeted the other strains.

  6. 浸矿微生物共培养体系在氟胁迫下的基因调控机理探索%Gene Regulation Mechanism of a Bioleaching Microbial Co-culture upon Fluoride Stress

    Institute of Scientific and Technical Information of China (English)

    李乾; 孙静; 丁德馨; 王清良; 马丽媛; 刘学端

    2015-01-01

    为了探明混合浸矿微生物的耐氟性能及其基因调控机理,应用功能基因芯片(FGA-Ⅱ)研究了5株浸矿细菌(Acidithiobacillus ferrooxidans ATCC 23270,Leptospirillum ferriphilum YSK, Sulfobacillus thermosulfidooxidans ST, Acidithiobacills thiooxidans A01, Acidithiobacills caldus S1)所构成的共培养体系在4.8 mmol/L氟胁迫下的基因表达谱.结果表明,该共培养体系中与氟胁迫相关的基因主要涉及到硫代谢、细胞膜、电子传递、解毒、碳固定、氮代谢等多个方面功能的代谢途径,而且各个途径在短时间(120 min)氟胁迫各个途径更倾向于低效表达.芯片图谱分析表明,氟胁迫下共培养体系中起主导调节作用的是其中的优势种群,但是劣势种群在氟胁迫时很大程度上辅助了优势种群的生长及其氧化活性的保持.%In order to explore the fluoride tolerance and the gene regulation mechanisms of mixed bioleaching microorganisms,the gene expression profile of a co-culture including five typical bioleaching strains ( Acidithiobacillus ferrooxidans ATCC 23270 , Leptospirillum fer-riphilum YSK,Sulfobacillus thermosulfidooxidans ST,Acidithiobacills thiooxidans A01,Acid-ithiobacills caldus S1 ) upon 4 . 8 mmol/L fluoride stress was investigated using the func-tional gene array. The results showed, the genes associated with fluoride stress were in-volved with sulfur metabolism,cell membrane,electron transport,detoxification,carbon fix-ation,nitrogen metabolism,and so on. Additionally,majority of genes was induced upon the short time ( 120 min) fluoride stress. The effects of fluoride stress on different microbial population in the co-cul-ture were different. The results revealed that the dominant species in the co-culture played the crucial role for resisting fluoride stress,while the minor species to a large extent assis-ted the oxidation ability preservation and growth of the dominant species.

  7. Spatial and Temporal Analysis of the Microbial Community in the Tailings of a Pb-Zn Mine Generating Acidic Drainage ▿ †

    Science.gov (United States)

    Huang, Li-Nan; Zhou, Wen-Hua; Hallberg, Kevin B.; Wan, Cai-Yun; Li, Jie; Shu, Wen-Sheng

    2011-01-01

    Analysis of spatial and temporal variations in the microbial community in the abandoned tailings impoundment of a Pb-Zn mine revealed distinct microbial populations associated with the different oxidation stages of the tailings. Although Acidithiobacillus ferrooxidans and Leptospirillum spp. were consistently present in the acidic tailings, acidophilic archaea, mostly Ferroplasma acidiphilum, were predominant in the oxidized zones and the oxidation front, indicating their importance to generation of acid mine drainage. PMID:21705549

  8. Mangiferin modulation of metabolism and metabolic syndrome.

    Science.gov (United States)

    Fomenko, Ekaterina Vladimirovna; Chi, Yuling

    2016-09-10

    The recent emergence of a worldwide epidemic of metabolic disorders, such as obesity and diabetes, demands effective strategy to develop nutraceuticals or pharmaceuticals to halt this trend. Natural products have long been and continue to be an attractive source of nutritional and pharmacological therapeutics. One such natural product is mangiferin (MGF), the predominant constituent of extracts of the mango plant Mangifera indica L. Reports on biological and pharmacological effects of MGF increased exponentially in recent years. MGF has documented antioxidant and anti-inflammatory effects. Recent studies indicate that it modulates multiple biological processes involved in metabolism of carbohydrates and lipids. MGF has been shown to improve metabolic abnormalities and disorders in animal models and humans. This review focuses on the recently reported biological and pharmacological effects of MGF on metabolism and metabolic disorders. © 2016 BioFactors, 42(5):492-503, 2016.

  9. Cold-induced metabolism

    NARCIS (Netherlands)

    Lichtenbelt, W. van Marken; Daanen, H.A.M.

    2003-01-01

    Purpose of review Cold response can be insulative (drop in peripheral temperature) or metabolic (increase in energy expenditure). Nonshivering thermogenesis by sympathetic, norepinephrine-induced mitochondrial heat production in brown adipose tissue is a well known component of this metabolic

  10. Cold-induced metabolism

    NARCIS (Netherlands)

    van Marken Lichtenbelt, W.D.; Daanen, A.M.

    2003-01-01

    Cold-induced metabolism. van Marken Lichtenbelt WD, Daanen HA. Department of Human Biology, Maastricht University, Maastricht, The Netherlands. PURPOSE OF REVIEW: Cold response can be insulative (drop in peripheral temperature) or metabolic (increase in energy expenditure). Nonshivering thermogenesi

  11. Lipid Metabolism Disorders

    Science.gov (United States)

    ... metabolic disorder, something goes wrong with this process. Lipid metabolism disorders, such as Gaucher disease and Tay-Sachs disease, involve lipids. Lipids are fats or fat-like substances. They ...

  12. Mineral metabolism in cats

    OpenAIRE

    Pineda Martos, Carmen María

    2014-01-01

    The present Doctoral Thesis wa metabolism in the feline species. Through a series of studies, the relationship between calcium metabolism and the main hormones involved in it has been determined metabolism during the juvenile stage of growing cats effects linked to feeding calculolytic diets on feline mineral metabolism. The first part of the work was aimed the quantification of intact (I-PTH) and whole PTH) and to characterize the dynamics of PTH secretion, including ...

  13. Engineering Cellular Metabolism

    DEFF Research Database (Denmark)

    Nielsen, Jens; Keasling, Jay

    2016-01-01

    of metabolic engineering and will discuss how new technologies can enable metabolic engineering to be scaled up to the industrial level, either by cutting off the lines of control for endogenous metabolism or by infiltrating the system with disruptive, heterologous pathways that overcome cellular regulation....

  14. Metabolic Engineering X Conference

    Energy Technology Data Exchange (ETDEWEB)

    Flach, Evan [American Institute of Chemical Engineers

    2015-05-07

    The International Metabolic Engineering Society (IMES) and the Society for Biological Engineering (SBE), both technological communities of the American Institute of Chemical Engineers (AIChE), hosted the Metabolic Engineering X Conference (ME-X) on June 15-19, 2014 at the Westin Bayshore in Vancouver, British Columbia. It attracted 395 metabolic engineers from academia, industry and government from around the globe.

  15. 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)

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

    2010-03-01

    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. Copyright 2009 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  16. Systems Biology of Metabolism.

    Science.gov (United States)

    Nielsen, Jens

    2017-06-20

    Metabolism is highly complex and involves thousands of different connected reactions; it is therefore necessary to use mathematical models for holistic studies. The use of mathematical models in biology is referred to as systems biology. In this review, the principles of systems biology are described, and two different types of mathematical models used for studying metabolism are discussed: kinetic models and genome-scale metabolic models. The use of different omics technologies, including transcriptomics, proteomics, metabolomics, and fluxomics, for studying metabolism is presented. Finally, the application of systems biology for analyzing global regulatory structures, engineering the metabolism of cell factories, and analyzing human diseases is discussed.

  17. Degradation of inhibitory substances in sludge by Galactomyces sp. Z3 and the role of its extracellular polymeric substances in improving bioleaching.

    Science.gov (United States)

    Zhou, Jun; Zheng, Guanyu; Wong, Jonathan W C; Zhou, Lixiang

    2013-03-01

    This study sought to elucidate the effect and mechanism of Galactomyces sp. Z3 in improving the bioleaching of heavy metals from sludge. Results showed that co-inoculation of Galactomyces sp. Z3 and two Acidithiobacillus strains (Acidithiobacillus ferrooxidans LX5 and Acidithiobacillus thiooxidans TS6) reduced the period required for sludge bioleaching by 4.5days compared to Acidithiobacillus alone. Further, removal efficiencies of Cu, Zn and oxidation rate of Fe(2+) and S(0) were higher in co-inoculation system than the Acidithiobacillus alone. Galactomyces sp. Z3 consumed the acetate, propionate, iso-butyrate, butyrate, and iso-valerate in sludge from the initial concentrations of 109.50, 28.80, 7.70, 34.30, and 18.40mg/L to 10.20, 0.61, 0.63, 19.40 and 1.30mg/L, respectively, after 12h in the co-inoculation system, significantly lower than the concentrations observed in the Acidithiobacillus alone. Meanwhile, the surfactant properties of the extracellular polymeric substances produced by the Galactomyces accelerated the rate of sulfur oxidization by A. thiooxidans.

  18. Sustained metabolic scope.

    Science.gov (United States)

    Peterson, C C; Nagy, K A; Diamond, J

    1990-03-01

    Sustained metabolic rates (SusMR) are time-averaged metabolic rates that are measured in free-ranging animals maintaining constant body mass over periods long enough that metabolism is fueled by food intake rather than by transient depletion of energy reserves. Many authors have suggested that SusMR of various wild animal species are only a few times resting (basal or standard) metabolic rates (RMR). We test this conclusion by analyzing all 37 species (humans, 31 other endothermic vertebrates, and 5 ectothermic vertebrates) for which SusMR and RMR had both been measured. For all species, the ratio of SusMR to RMR, which we term sustained metabolic scope, is less than 7; most values fall between 1.5 and 5. Some of these values, such as those for Tour de France cyclists and breeding birds, are surely close to sustainable metabolic ceilings for the species studied. That is, metabolic rates higher than 7 times RMR apparently cannot be sustained indefinitely. These observations pose several questions: whether the proximate physiological causes of metabolic ceilings reside in the digestive tract's ability to process food or in each tissue's metabolic capacity; whether ceiling values are independent of the mode of energy expenditure; whether ceilings are set by single limiting physiological capacities or by coadjusted clusters of capacities (symmorphosis); what the ultimate evolutionary causes of metabolic ceilings are; and how metabolic ceilings may limit animals' reproductive effort, foraging behavior, and geographic distribution.

  19. Comparative genomic analysis of carbon and nitrogen assimilation mechanisms in three indigenous bioleaching bacteria: predictions and validations

    Directory of Open Access Journals (Sweden)

    Ehrenfeld Nicole

    2008-12-01

    Full Text Available Abstract Background Carbon and nitrogen fixation are essential pathways for autotrophic bacteria living in extreme environments. These bacteria can use carbon dioxide directly from the air as their sole carbon source and can use different sources of nitrogen such as ammonia, nitrate, nitrite, or even nitrogen from the air. To have a better understanding of how these processes occur and to determine how we can make them more efficient, a comparative genomic analysis of three bioleaching bacteria isolated from mine sites in Chile was performed. This study demonstrated that there are important differences in the carbon dioxide and nitrogen fixation mechanisms among bioleaching bacteria that coexist in mining environments. Results In this study, we probed that both Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans incorporate CO2 via the Calvin-Benson-Bassham cycle; however, the former bacterium has two copies of the Rubisco type I gene whereas the latter has only one copy. In contrast, we demonstrated that Leptospirillum ferriphilum utilizes the reductive tricarboxylic acid cycle for carbon fixation. Although all the species analyzed in our study can incorporate ammonia by an ammonia transporter, we demonstrated that Acidithiobacillus thiooxidans could also assimilate nitrate and nitrite but only Acidithiobacillus ferrooxidans could fix nitrogen directly from the air. Conclusion The current study utilized genomic and molecular evidence to verify carbon and nitrogen fixation mechanisms for three bioleaching bacteria and provided an analysis of the potential regulatory pathways and functional networks that control carbon and nitrogen fixation in these microorganisms.

  20. Metabolic enzymes link morphine withdrawal with metabolic disorder

    Institute of Scientific and Technical Information of China (English)

    Xi Jiang; Jing Li; Lan Ma

    2007-01-01

    @@ Energy metabolism is a fundamental biological process that is vital for the survival of all species. Disorders in the metabolic system result in deficiency or redundancy of certain nutrients, including carbohydrates, lipids, amino acids, etc. Abnormality of the energy metabolism system leads to a number of metabolic diseases, such as the metabolic syndrome. Broadly speaking, the term "metabolic diseases" now tends to be widened to the category that refers to all diseases with metabolism disorder.

  1. Engineering Cellular Metabolism.

    Science.gov (United States)

    Nielsen, Jens; Keasling, Jay D

    2016-03-10

    Metabolic engineering is the science of rewiring the metabolism of cells to enhance production of native metabolites or to endow cells with the ability to produce new products. The potential applications of such efforts are wide ranging, including the generation of fuels, chemicals, foods, feeds, and pharmaceuticals. However, making cells into efficient factories is challenging because cells have evolved robust metabolic networks with hard-wired, tightly regulated lines of communication between molecular pathways that resist efforts to divert resources. Here, we will review the current status and challenges of metabolic engineering and will discuss how new technologies can enable metabolic engineering to be scaled up to the industrial level, either by cutting off the lines of control for endogenous metabolism or by infiltrating the system with disruptive, heterologous pathways that overcome cellular regulation.

  2. Metabolic syndrome and migraine

    Directory of Open Access Journals (Sweden)

    Amit eSachdev

    2012-11-01

    Full Text Available Migraine and metabolic syndrome are highly prevaleirnt and costly conditions.The two conditions coexist, but it is unclear what relationship may exist between the two processes. Metabolic syndrome involves a number of findings, including insulin resistance, systemic hypertension, obesity, a proinflammatory state, and a prothrombotic state. Only one study addresses migraine in metabolic syndrome, finding significant differences in the presentation of metabolic syndrome in migraineurs. However, controversy exists regarding the contribution of each individual risk factor to migraine pathogensis and prevalence. It is unclear what treatment implications, if any, exist as a result of the concomitant diagnosis of migraine and metabolic syndrome. The cornerstone of migraine and metabolic syndrome treatments is prevention, relying heavily on diet modification, sleep hygiene, medication use, and exercise.

  3. Metabolic disorders in menopause

    OpenAIRE

    Grzegorz Stachowiak; Tomasz Pertyński; Magdalena Pertyńska-Marczewska

    2015-01-01

    Metabolic disorders occurring in menopause, including dyslipidemia, disorders of carbohydrate metabolism (impaired glucose tolerance – IGT, type 2 diabetes mellitus – T2DM) or components of metabolic syndrome, constitute risk factors for cardiovascular disease in women. A key role could be played here by hyperinsulinemia, insulin resistance and visceral obesity, all contributing to dyslipidemia, oxidative stress, inflammation, alter coagulation and atherosclerosis observed during the menopaus...

  4. METABOLISM OF IRON STORES

    OpenAIRE

    Saito, Hiroshi

    2014-01-01

    ABSTRACT Remarkable progress was recently achieved in the studies on molecular regulators of iron metabolism. Among the main regulators, storage iron, iron absorption, erythropoiesis and hepcidin interact in keeping iron homeostasis. Diseases with gene-mutations resulting in iron overload, iron deficiency, and local iron deposition have been introduced in relation to the regulators of storage iron metabolism. On the other hand, the research on storage iron metabolism has not advanced since th...

  5. Genetic and metabolic engineering

    OpenAIRE

    Yang,Yea-Tyng; Bennett, George N.; San, Ka-yiu

    1998-01-01

    Recent advances in molecular biology techniques, analytical methods and mathematical tools have led to a growing interest in using metabolic engineering to redirect metabolic fluxes for industrial and medical purposes. Metabolic engineering is referred to as the directed improvement of cellular properties through the modification of specific biochemical reactions or the introduction of new ones, with the use of recombinant DNA technology (Stephanopoulos, 1999). This multidisciplinary field dr...

  6. Inflammation and metabolic cardiomyopathy.

    Science.gov (United States)

    Nishida, Kazuhiko; Otsu, Kinya

    2017-03-15

    Excessive feeding is associated with an increase in the incidence of chronic metabolic diseases, such as obesity, insulin resistance, and type 2 diabetes. Metabolic disturbance induces chronic low-grade inflammation in metabolically-important organs, such as the liver and adipose tissue. Many of the inflammatory signalling pathways are directly triggered by nutrients. The pro-inflammatory mediators in adipocytes and macrophages infiltrating adipose tissue promote both local and systemic pro-inflammatory status. Metabolic cardiomyopathy is a chronic metabolic disease characterized by structural and functional alterations and interstitial fibrosis without coronary artery disease or hypertension. In the early stage of metabolic cardiomyopathy, metabolic disturbance is not accompanied by substantial changes in myocardial structure and cardiac function. However, metabolic disturbance induces subcellular low-grade inflammation in the heart, and in turn, subcellular component abnormalities, such as oxidative stress, mitochondrial dysfunction, endoplasmic reticulum stress, and impaired calcium handling, leading to impaired myocardial relaxation. In the advanced stage, the vicious cycle of subcellular component abnormalities, inflammatory cell infiltration, and neurohumoral activation induces cardiomyocyte injury and death, and cardiac fibrosis, resulting in impairment of both diastolic and systolic functions. This review discusses some recent advances in understanding involvement of inflammation in metabolic cardiomyopathy. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.

  7. What is Nutrition & Metabolism?

    Science.gov (United States)

    Feinman, Richard D; Hussain, M Mahmood

    2004-08-17

    A new Open Access journal, Nutrition & Metabolism (N&M) will publish articles that integrate nutrition with biochemistry and molecular biology. The open access process is chosen to provide rapid and accessible dissemination of new results and perspectives in a field that is of great current interest. Manuscripts in all areas of nutritional biochemistry will be considered but three areas of particular interest are lipoprotein metabolism, amino acids as metabolic signals, and the effect of macronutrient composition of diet on health. The need for the journal is identified in the epidemic of obesity, diabetes, dyslipidemias and related diseases, and a sudden increase in popular diets, as well as renewed interest in intermediary metabolism.

  8. Mathematical modelling of metabolism

    DEFF Research Database (Denmark)

    Gombert, Andreas Karoly; Nielsen, Jens

    2000-01-01

    Mathematical models of the cellular metabolism have a special interest within biotechnology. Many different kinds of commercially important products are derived from the cell factory, and metabolic engineering can be applied to improve existing production processes, as well as to make new processes...... available. Both stoichiometric and kinetic models have been used to investigate the metabolism, which has resulted in defining the optimal fermentation conditions, as well as in directing the genetic changes to be introduced in order to obtain a good producer strain or cell line. With the increasing...... availability of genomic information and powerful analytical techniques, mathematical models also serve as a tool for understanding the cellular metabolism and physiology....

  9. Fluoroacetylcarnitine: metabolism and metabolic effects in mitochondria

    Energy Technology Data Exchange (ETDEWEB)

    Bremer, J.; Davis, E.J.

    1973-01-01

    The metabolism and metabolic effects of fluoroacetylcarnitine have been investigated. Carnitineacetyltransferase transfers the fluoro-acetyl group of fluoroacetylcarnitine nearly as rapidly to CoA as the acetyl group of acetylcarnitine. Fluorocitrate is then formed by citrate synthase, but this second reaction is relatively slow. The fluorocitrate formed intramitochondrially inhibits the metabolism of citrate. In heart and skeletal muscle mitochondria the accumulated citrate inhibits citrate synthesis and the ..beta..-oxidation of fatty acids. Free acetate is formed, presumably because accumulated acetyl-CoA is hydrolyzed. In liver mitochondria the accumulation of citrate leads to a relatively increased rate of ketogenesis. Increased ketogenesis is obtained also upon the addition of citrate to the reaction mixture.

  10. Attractor metabolic networks.

    Directory of Open Access Journals (Sweden)

    Ildefonso M De la Fuente

    Full Text Available BACKGROUND: The experimental observations and numerical studies with dissipative metabolic networks have shown that cellular enzymatic activity self-organizes spontaneously leading to the emergence of a Systemic Metabolic Structure in the cell, characterized by a set of different enzymatic reactions always locked into active states (metabolic core while the rest of the catalytic processes are only intermittently active. This global metabolic structure was verified for Escherichia coli, Helicobacter pylori and Saccharomyces cerevisiae, and it seems to be a common key feature to all cellular organisms. In concordance with these observations, the cell can be considered a complex metabolic network which mainly integrates a large ensemble of self-organized multienzymatic complexes interconnected by substrate fluxes and regulatory signals, where multiple autonomous oscillatory and quasi-stationary catalytic patterns simultaneously emerge. The network adjusts the internal metabolic activities to the external change by means of flux plasticity and structural plasticity. METHODOLOGY/PRINCIPAL FINDINGS: In order to research the systemic mechanisms involved in the regulation of the cellular enzymatic activity we have studied different catalytic activities of a dissipative metabolic network under different external stimuli. The emergent biochemical data have been analysed using statistical mechanic tools, studying some macroscopic properties such as the global information and the energy of the system. We have also obtained an equivalent Hopfield network using a Boltzmann machine. Our main result shows that the dissipative metabolic network can behave as an attractor metabolic network. CONCLUSIONS/SIGNIFICANCE: We have found that the systemic enzymatic activities are governed by attractors with capacity to store functional metabolic patterns which can be correctly recovered from specific input stimuli. The network attractors regulate the catalytic patterns

  11. Cold-induced metabolism

    NARCIS (Netherlands)

    Lichtenbelt, W. van Marken; Daanen, H.A.M.

    2003-01-01

    Purpose of review Cold response can be insulative (drop in peripheral temperature) or metabolic (increase in energy expenditure). Nonshivering thermogenesis by sympathetic, norepinephrine-induced mitochondrial heat production in brown adipose tissue is a well known component of this metabolic respon

  12. Circadian Systems and Metabolism

    NARCIS (Netherlands)

    Roenneberg, Till; Merrow, Martha

    1999-01-01

    Circadian systems direct many metabolic parameters and, at the same time, they appear to be exquisitely shielded from metabolic variations. Although the recent decade of circadian research has brought insights into how circadian periodicity may be generated at the molecular level, little is known ab

  13. Metabolic Engineering VII Conference

    Energy Technology Data Exchange (ETDEWEB)

    Kevin Korpics

    2012-12-04

    The aims of this Metabolic Engineering conference are to provide a forum for academic and industrial researchers in the field; to bring together the different scientific disciplines that contribute to the design, analysis and optimization of metabolic pathways; and to explore the role of Metabolic Engineering in the areas of health and sustainability. Presentations, both written and oral, panel discussions, and workshops will focus on both applications and techniques used for pathway engineering. Various applications including bioenergy, industrial chemicals and materials, drug targets, health, agriculture, and nutrition will be discussed. Workshops focused on technology development for mathematical and experimental techniques important for metabolic engineering applications will be held for more in depth discussion. This 2008 meeting will celebrate our conference tradition of high quality and relevance to both industrial and academic participants, with topics ranging from the frontiers of fundamental science to the practical aspects of metabolic engineering.

  14. Disorders of fructose metabolism.

    Science.gov (United States)

    Froesch, E R

    1976-11-01

    There are fundamental differences between the metabolic fate of fructose and of glucose. Whereas the metabolism of glucose is controlled by hormones such as insulin, fructose uptake and phosphorylation in the liver occurs independently of hormones and its ultimate metabolic fate is unpredictable. Essential fructosuria, a harmless inherited anomaly of fructose metabolism, is the least harmful of the disorders of fructose metabolism. Hereditary fructose intolerance and fructose-1,6-diphosphatase deficiency are discussed in greater detail with regard to biochemical abnormalities and clinical aspects. HFI is most serious in bottle-fed infants who cannot reject their sucrose-containing diet. Patients with HFI will have no clinical symptoms if kept on a fructose-free diet. In contrast, patients with fructose-1,6-diphosphatase deficiency can tolerate frucose. However, severe infections precipitate attacks of hypoglycaemia and lactic acidosis.

  15. Primary Metabolic Pathways and Metabolic Flux Analysis

    DEFF Research Database (Denmark)

    2015-01-01

    his chapter introduces the metabolic flux analysis (MFA) or stoichiometry-based MFA, and describes the quantitative basis for MFA. It discusses the catabolic pathways in which free energy is produced to drive the cell-building anabolic pathways. An overview of these primary pathways provides...

  16. Changes in the composition of an acid mine drainage microbial community upon successive transfers in medium containing low-grade copper sulfide.

    Science.gov (United States)

    Liu, Yi; Yin, Huaqun; Liang, Yili; Shen, Li; Liu, Yao; Fu, Xian; Baba, Ngom; Zeng, Weimin; Qiu, Guanzhou; Liu, Xueduan

    2011-10-01

    A consortium of microorganisms from acid mine drainage samples was cultured in modified 9 K medium containing low-grade copper sulfide. The culture was maintained for sixty days and then transferred to fresh medium. This process was repeated three more times and a final consortium exhibiting a copper extraction rate of 89.3% was obtained. RFLP and microarrays analysis of 16S rRNA sequences retrieved from the consortia showed that Acidithiobacilluscaldus, Leptospirillumferriphilum, Sulfobacillus sp., Acidiphilium sp., and Sulfolobus spp. were represented in higher numbers in the consortia obtained in the copper-containing medium than in the original consortium. In contrast, a decrease in Acidithiobacillus ferrooxidans, Alicyclobacillus sp., Pseudomonas sp., and Sulfobacillus thermosulfidooxidans was observed. The abundance of genes related to sulfur metabolism from At. caldus and Sulfolobus spp., iron oxidation from Leptospirillum sp. and metal resistance from most of the detected microorganisms increased as the consortium was successively transferred into fresh medium. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Metabolic disorders in menopause

    Directory of Open Access Journals (Sweden)

    Grzegorz Stachowiak

    2015-04-01

    Full Text Available Metabolic disorders occurring in menopause, including dyslipidemia, disorders of carbohydrate metabolism (impaired glucose tolerance – IGT, type 2 diabetes mellitus – T2DM or components of metabolic syndrome, constitute risk factors for cardiovascular disease in women. A key role could be played here by hyperinsulinemia, insulin resistance and visceral obesity, all contributing to dyslipidemia, oxidative stress, inflammation, alter coagulation and atherosclerosis observed during the menopausal period. Undiagnosed and untreated, metabolic disorders may adversely affect the length and quality of women’s life. Prevention and treatment preceded by early diagnosis should be the main goal for the physicians involved in menopausal care. This article represents a short review of the current knowledge concerning metabolic disorders (e.g. obesity, polycystic ovary syndrome or thyroid diseases in menopause, including the role of a tailored menopausal hormone therapy (HT. According to current data, HT is not recommend as a preventive strategy for metabolic disorders in menopause. Nevertheless, as part of a comprehensive strategy to prevent chronic diseases after menopause, menopausal hormone therapy, particularly estrogen therapy may be considered (after balancing benefits/risks and excluding women with absolute contraindications to this therapy. Life-style modifications, with moderate physical activity and healthy diet at the forefront, should be still the first choice recommendation for all patients with menopausal metabolic abnormalities.

  18. Metabolic disorders in menopause.

    Science.gov (United States)

    Stachowiak, Grzegorz; Pertyński, Tomasz; Pertyńska-Marczewska, Magdalena

    2015-03-01

    Metabolic disorders occurring in menopause, including dyslipidemia, disorders of carbohydrate metabolism (impaired glucose tolerance - IGT, type 2 diabetes mellitus - T2DM) or components of metabolic syndrome, constitute risk factors for cardiovascular disease in women. A key role could be played here by hyperinsulinemia, insulin resistance and visceral obesity, all contributing to dyslipidemia, oxidative stress, inflammation, alter coagulation and atherosclerosis observed during the menopausal period. Undiagnosed and untreated, metabolic disorders may adversely affect the length and quality of women's life. Prevention and treatment preceded by early diagnosis should be the main goal for the physicians involved in menopausal care. This article represents a short review of the current knowledge concerning metabolic disorders (e.g. obesity, polycystic ovary syndrome or thyroid diseases) in menopause, including the role of a tailored menopausal hormone therapy (HT). According to current data, HT is not recommend as a preventive strategy for metabolic disorders in menopause. Nevertheless, as part of a comprehensive strategy to prevent chronic diseases after menopause, menopausal hormone therapy, particularly estrogen therapy may be considered (after balancing benefits/risks and excluding women with absolute contraindications to this therapy). Life-style modifications, with moderate physical activity and healthy diet at the forefront, should be still the first choice recommendation for all patients with menopausal metabolic abnormalities.

  19. Regulation of lipid metabolism

    Institute of Scientific and Technical Information of China (English)

    Peng LI

    2011-01-01

    @@ Lipids including cholesterol, phospholipids, fatty acids and triacylglycerols are important cellular constituents involved in membrane structure, energy homeostasis and many biological processes such as signal transduction, organelle development and cell differentiation.Recently, the area of lipid metabolism has drawn a great deal of attention due to its emerging role in the development of metabolic disorders such as obesity, diabetes, atherosclerosis and liver steatosis.We decided to organize a special issue of Frontiers in Biology focusing on our current understanding of lipid metabolism.

  20. A Metabolic Switch

    DEFF Research Database (Denmark)

    Hjorth, Poul G.

    Our muscles are metabolically flexible, i.e., they are capable of `switching' between two types of oxidation: (1) when fasting, a predominantly lipid oxidation with high rates of fatty acid uptake, and (2) when fed, suppression of lipid oxidation in favour of increased glucose uptake, oxidation...... and storage, in response to insulin. One of the many manifestations of obesity and Type 2 diabetes is an insulin resistance of the skeletal muscles, which suppresses this metabolic switch. This talk describes recent development of a low-dimensional system of ODEs that model the metabolic switch, displaying...

  1. Sirtuins, Metabolism and Cancer

    Directory of Open Access Journals (Sweden)

    Barbara eMartinez-Pastor

    2012-02-01

    Full Text Available More than a decade ago, sirtuins were discovered as a highly conserved family of NAD+-dependent enzymes that extend lifespan in lower organisms. In mammals, sirtuins are key regulators of stress responses and metabolism, influencing a range of diseases, including diabetes, neurodegeneration and cancer. In recent years, new functions of sirtuins have been characterized, uncovering the underlying mechanisms of their multifaceted role in metabolism. Here, we specifically review recent progress on the role of sirtuins in DNA repair and energy metabolism, further discussing the implication of sirtuins in the biology of cancer.

  2. Vitamin D metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Deluca, H.F.

    1977-01-01

    During the past decade, an explosion of information has become available on the metabolism and function of vitamin D which is of great importance to clinicians in the treatment of metabolic bone disease. We have learned that vitamin D is the precursor of at least one hormone and that this hormone carries out functions in calcium and phosphorus metabolism bringing about mineralization of bone on one hand, and the prevention of hypocalcaemic tetany on the other. It may also function in the prevention of such degenerative bone diseases as osteoporosis. An important analogue of this hormone, 1..cap alpha..-hydroxyvitamin D/sub 3/ has been prepared and is used successfully in the treatment of a variety of clinical conditions. This presentation will summarize these findings and their possible implications in these metabolic bone diseases.

  3. What is Nutrition & Metabolism?

    Directory of Open Access Journals (Sweden)

    Feinman Richard D

    2004-08-01

    Full Text Available Abstract A new Open Access journal, Nutrition & Metabolism (N&M will publish articles that integrate nutrition with biochemistry and molecular biology. The open access process is chosen to provide rapid and accessible dissemination of new results and perspectives in a field that is of great current interest. Manuscripts in all areas of nutritional biochemistry will be considered but three areas of particular interest are lipoprotein metabolism, amino acids as metabolic signals, and the effect of macronutrient composition of diet on health. The need for the journal is identified in the epidemic of obesity, diabetes, dyslipidemias and related diseases, and a sudden increase in popular diets, as well as renewed interest in intermediary metabolism.

  4. Metabolism. Part III: Lipids.

    Science.gov (United States)

    Bodner, George M.

    1986-01-01

    Describes the metabolic processes of complex lipids, including saponification, activation and transport, and the beta-oxidation spiral. Discusses fatty acid degradation in regard to biochemical energy and ketone bodies. (TW)

  5. Amino Acid Metabolism Disorders

    Science.gov (United States)

    ... this process. One group of these disorders is amino acid metabolism disorders. They include phenylketonuria (PKU) and maple syrup urine disease. Amino acids are "building blocks" that join together to form ...

  6. Sleep & the metabolic syndrome

    National Research Council Canada - National Science Library

    Lam, Jamie C M; Ip, Mary S M

    2010-01-01

    Sleep is an essential part of our daily living, and sleep disturbances may intervene with the biological and physiological processes in human body leading to the development of metabolic dysfunction...

  7. Epigenetics and Cellular Metabolism

    Science.gov (United States)

    Xu, Wenyi; Wang, Fengzhong; Yu, Zhongsheng; Xin, Fengjiao

    2016-01-01

    Living eukaryotic systems evolve delicate cellular mechanisms for responding to various environmental signals. Among them, epigenetic machinery (DNA methylation, histone modifications, microRNAs, etc.) is the hub in transducing external stimuli into transcriptional response. Emerging evidence reveals the concept that epigenetic signatures are essential for the proper maintenance of cellular metabolism. On the other hand, the metabolite, a main environmental input, can also influence the processing of epigenetic memory. Here, we summarize the recent research progress in the epigenetic regulation of cellular metabolism and discuss how the dysfunction of epigenetic machineries influences the development of metabolic disorders such as diabetes and obesity; then, we focus on discussing the notion that manipulating metabolites, the fuel of cell metabolism, can function as a strategy for interfering epigenetic machinery and its related disease progression as well. PMID:27695375

  8. [Metabolic syndrome and melatonin].

    Science.gov (United States)

    Rapoport, S I; Molchanov, A Iu; Golichenkov, V A; Burlakova, O V; Suprunenko, E S; Savchenko, E S

    2013-01-01

    Metabolic syndrome (MS) is characterized by the following symptoms: obesity, AH, dyslipidemia, insulin resistance. Pathophysiologically, MS is underlain by disorders of many biochemical and physiological processes, such as elevated levels of low density lipoproteins, hyperstimulation of pancreatic b-cells, increased insulin secretion, substitution of lipid metabolism for carbohydrate one, overgrowth of adipose tissue, excess production of adiponectin, leptin and other signal molecules and a rise in their local intravascular concentration, weight gain. Endogenous and exogenous melatonin inhibits these pathophysiological mechanisms, normalizes metabolism, equilibrates insulin secretion, prevents pancreatic hyperfunction, phosphorylates insulin receptors, inactivates active oxygen and nitrogen species including those produced in LDLP metabolism. Melatonin has specific MT1 and MT2 receptors localized in all body cells. Due to this, it exerts combined preventive action in patients with MS. Recently, melatonin has been reported to have therapeutic effect in MS; it may be recommended to treat this condition.

  9. Endocrine and Metabolic Disorders

    Science.gov (United States)

    ... for disorders of endocrine glands other than the thyroid, compared to 3.1 percent of visits made by women. The rate of visits due to metabolic and immunity disorders was also higher among men than women (2. ...

  10. Copper, zinc, and iron bioleaching from polymetallic sulphide concentrate%多金属硫化精矿中铜、锌和铁的生物浸出

    Institute of Scientific and Technical Information of China (English)

    Vesna T. CONIĆ; Mirjana M. RAJČIĆ VUJASINOVIĆ; Vlastimir K. TRUJIĆ; Vladimir B. CVETKOVSKI

    2014-01-01

    Bioleaching of low-grade complex Cu−Zn−Pb−Fe−Ag−Au sulphide concentrate (of Majdanpek ore body, RTB Bor, Serbia) was carried out in an aerated bioleach reactor in the presence of mesophilic mixed bacterial culture ofAcidithiobacillus ferrooxidans,Acidithiobacillus thiooxidans, andLeptospirillum ferrooxidans. A mesophilic acidophiles culture was isolated from the acidic solution of the underground copper mine of Bor, Serbia. The nutrient medium was 9K at pH 1.6. 87% of the particles were<10 µm in size, with a pulp density of 8% (w/v). Bioleaching efficiencies of 89% for zinc, 83% for copper, and 68% for iron can be achieved in the examined conditions. Kinetic analysis shows that the change in leaching corresponds to the Spencer-Topley kinetic model for diffusion-controlled topochemical reactions.%利用嗜温混合菌Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans和 Leptospirillum ferrooxidans对低品位复杂Cu−Zn−Pb−Fe−Ag−Au硫化精矿在曝气生物浸出反应器中进行生物浸出。该菌种为从塞尔维亚Bor地下铜矿的酸性溶液中筛选出一种嗜热嗜酸菌。营养液为pH 1.6的9K营养液。87%的矿物粒度大于10μm,矿浆密度为8%(w/v)。在测试条件下,锌、铜和铁的浸出率分别达到89%、83%和68%。动力学分析表明,浸出过程与Spencer-Topley模型相符,受局部反应扩散控制。

  11. Hypothalamic Hormones and Metabolism

    OpenAIRE

    Thio, Liu Lin

    2012-01-01

    The ketogenic diet is an effective treatment for medically intractable epilepsy and may have antiepileptogenic, neuroprotective, and antitumor properties. While on a ketogenic diet, the body obtains most of its calories from fat rather than carbohydrates. This dramatic change in caloric composition results in a unique metabolic state. In turn, these changes in caloric composition and metabolism alter some of the neurohormones that participate in the complex neuronal network regulating energy ...

  12. Tumor cell metabolism

    Science.gov (United States)

    Romero-Garcia, Susana; Lopez-Gonzalez, Jose Sullivan; B´ez-Viveros, José Luis; Aguilar-Cazares, Dolores

    2011-01-01

    Cancer is a genetic disease that is caused by mutations in oncogenes, tumor suppressor genes and stability genes. The fact that the metabolism of tumor cells is altered has been known for many years. However, the mechanisms and consequences of metabolic reprogramming have just begun to be understood. In this review, an integral view of tumor cell metabolism is presented, showing how metabolic pathways are reprogrammed to satisfy tumor cell proliferation and survival requirements. In tumor cells, glycolysis is strongly enhanced to fulfill the high ATP demands of these cells; glucose carbons are the main building blocks in fatty acid and nucleotide biosynthesis. Glutaminolysis is also increased to satisfy NADPH regeneration, whereas glutamine carbons replenish the Krebs cycle, which produces metabolites that are constantly used for macromolecular biosynthesis. A characteristic feature of the tumor microenvironment is acidosis, which results from the local increase in lactic acid production by tumor cells. This phenomenon is attributed to the carbons from glutamine and glucose, which are also used for lactic acid production. Lactic acidosis also directs the metabolic reprogramming of tumor cells and serves as an additional selective pressure. Finally, we also discuss the role of mitochondria in supporting tumor cell metabolism. PMID:22057267

  13. Optimum condition in Cr3+ bioleaching of tannery sludge with Thiobacillus ferrooxidans LX5, Thiobacillus thiooxidans TS6 and Rhodotorula sp. R30%酵母菌与两种硫杆菌复合对污泥中三价铬的去除

    Institute of Scientific and Technical Information of China (English)

    王世梅; 周立祥; 黄峰源

    2006-01-01

    研究了氧化亚铁硫杆菌LX5(Thiobacillus ferrooxidans LX5)、氧化硫硫杆菌TS6(Thiobacillus thiooxidans TS6)和耐酸性酵母菌R30(Rhodotorula sp.R30)对重金属铬(Cr3+)的耐受性.结果表明,700mg/L的Cr3+对硫杆菌LX5、TS6的生长和氧化活性影响不大,但Cr3+浓度大于500mg/L时明显抑制酵母菌R30的生长.酵母菌R30与硫杆菌LX5和TS6复合能明显加速污泥淋滤的进程,最佳复合比为酵母菌R30接种量2.0%,硫杆菌LX5和TS6接种量10%.分别用含酵母菌R30数量为104个/mL和102个/mL的酸化污泥作接种物进行污泥淋滤,发现淋滤过程中pH值下降的速度没有明显差异,而在淋滤起始时添加2.0%的酵母菌R30,则淋滤反应提前36h结束.由此可见,在其它条件相同的污泥淋滤中,污泥中所含耐酸性酵母菌的数量是加快淋滤的关键.

  14. Evolutionary dynamics of metabolic adaptation

    NARCIS (Netherlands)

    van Hoek, M.J.A.

    2008-01-01

    In this thesis we study how organisms adapt their metabolism to a changing environment. Metabolic adaptation occurs at different timescales. Organisms adapt their metabolism via metabolic regulation, which happens in the order of minutes to hours and via evolution, which takes many generations. Here

  15. Evolutionary dynamics of metabolic adaptation

    NARCIS (Netherlands)

    van Hoek, M.J.A.

    2008-01-01

    In this thesis we study how organisms adapt their metabolism to a changing environment. Metabolic adaptation occurs at different timescales. Organisms adapt their metabolism via metabolic regulation, which happens in the order of minutes to hours and via evolution, which takes many generations. Here

  16. Metabolism, temperature, and ventilation.

    Science.gov (United States)

    Mortola, Jacopo P; Maskrey, Michael

    2011-10-01

    In mammals and birds, all oxygen used (VO2) must pass through the lungs; hence, some degree of coupling between VO2 and pulmonary ventilation (VE) is highly predictable. Nevertheless, VE is also involved with CO2 elimination, a task that is often in conflict with the convection of O2. In hot or cold conditions, the relationship between VE and VO2 includes the participation of the respiratory apparatus to the control of body temperature and water balance. Some compromise among these tasks is achieved through changes in breathing pattern, uncoupling changes in alveolar ventilation from VE. This article examines primarily the relationship between VE and VO2 under thermal stimuli. In the process, it considers how the relationship is influenced by hypoxia, hypercapnia or changes in metabolic level. The shuffling of tasks in emergency situations illustrates that the constraints on VE-VO2 for the protection of blood gases have ample room for flexibility. However, when other priorities do not interfere with the primary goal of gas exchange, VE follows metabolic rate quite closely. The fact that arterial CO2 remains stable when metabolism is changed by the most diverse circumstances (moderate exercise, cold, cold and exercise combined, variations in body size, caloric intake, age, time of the day, hormones, drugs, etc.) makes it unlikely that VE and metabolism are controlled in parallel by the condition responsible for the metabolic change. Rather, some observations support the view that the gaseous component of metabolic rate, probably CO2, may provide the link between the metabolic level and VE.

  17. Metabolic surgery: quo vadis?

    Science.gov (United States)

    Ramos-Leví, Ana M; Rubio Herrera, Miguel A

    2014-01-01

    The impact of bariatric surgery beyond its effect on weight loss has entailed a change in the way of regarding it. The term metabolic surgery has become more popular to designate those interventions that aim at resolving diseases that have been traditionally considered as of exclusive medical management, such as type 2 diabetes mellitus (T2D). Recommendations for metabolic surgery have been largely addressed and discussed in worldwide meetings, but no definitive consensus has been reached yet. Rates of diabetes remission after metabolic surgery have been one of the most debated hot topics, with heterogeneity being a current concern. This review aims to identify and clarify controversies regarding metabolic surgery, by focusing on a critical analysis of T2D remission rates achieved with different bariatric procedures, and using different criteria for its definition. Indications for metabolic surgery for patients with T2D who are not morbidly obese are also discussed. Copyright © 2013 SEEN. Published by Elsevier Espana. All rights reserved.

  18. Nutrition and metabolic syndrome.

    Directory of Open Access Journals (Sweden)

    Albornoz López, Raúl

    2012-12-01

    Full Text Available The metabolic syndrome comprises a cluster of metabolic abnormalities that increase the risk for cardiovascular disease and type 2 diabetes mellitus. The exact etiology is unclear, although it is known thatthere is a complex interaction between genetic, metabolic and environmental factors. Among the environmental factors, dietary habits play an important role in the treatment and prevention of this condition. General classic recommendations include control of obesity, increased physical activity, decreased intake of saturated fat and cholesterol, reduced intake of simple sugars and increased intake of fruits and vegetables. It has been studied the influence of diets low in carbohydrates, diets rich in polyunsaturated and monounsaturated fatty acids, fiber intake, the Mediterranean diet and the glycemic index in relation to metabolic syndrome.Other nutrients recently studied are the micronutrients (magnesium and calcium, soy and other phytochemicals. Evidence suggests that a healthy diet like the Mediterranean protects against metabolic syndrome,caracterized for a low content in saturated and trans fat, high in monounsaturated and polyunsaturated fatty acids, balanced intake of carbohydrates and high in fiber, fruits and vegetables. There is more controversy about the type of diet of choice for the control ofmetabolic syndrome (low-carbohydrate diets or lowfat, needing more studies on the role of soy and other phytochemicals.

  19. Apelin and energy metabolism

    Directory of Open Access Journals (Sweden)

    Chantal eBertrand

    2015-04-01

    Full Text Available A wide range of adipokines identified over the past years has allowed considering white adipose tissue as a secretory organ closely integrated into overall physiological and metabolic control. Apelin, an ubiquitous peptide was known to exert different physiological effects mainly on the cardiovascular system and the regulation of fluid homeostasis until its identification as an adipokine. This has increased its broad range of action and apelin now appears clearly as a new player in energy metabolism alongside leptin and adiponectin. Apelin has been shown to act on glucose and lipid metabolism but also to modulate insulin secretion. Moreover, different studies in both animals and humans have shown that plasma apelin concentrations are usually increased during obesity and type 2 diabetes. This mini-review will focus on the various systemic apelin effects on energy metabolism by addressing its mechanisms of action. The advances concerning the role of apelin in metabolic diseases in relation with the recent reports on apelin concentrations in obese and/or diabetic subjects will also be discussed.

  20. Metabolism of phencyclidine

    Energy Technology Data Exchange (ETDEWEB)

    Hoag, M.K.P.

    1987-01-01

    Phencyclidine (PCP) is a drug of abuse which may produce, in some users, a persistent schizophreniform psychosis. The possibility that long term effects of PCP are mediated by metabolic activation of the parent compound to reactive species is consistent with the demonstration of metabolism-dependent covalent binding of radiolabeled PCP in vivo and in vitro to macromolecules in rodent lung, liver, and kidney. Formation of the electrophilic iminium ion metabolite of PCP is believed to be critical for covalent binding since binding was inhibited by cyanide ion at concentrations which did not inhibit metabolism of PCP but did trap the iminium ion to form the corresponding alpha-aminonitrile. The present studies were designed to characterize further the biological fate of PCP by identifying possible macromolecular targets of the reactive metabolite(s).

  1. Analytics for Metabolic Engineering.

    Science.gov (United States)

    Petzold, Christopher J; Chan, Leanne Jade G; Nhan, Melissa; Adams, Paul D

    2015-01-01

    Realizing the promise of metabolic engineering has been slowed by challenges related to moving beyond proof-of-concept examples to robust and economically viable systems. Key to advancing metabolic engineering beyond trial-and-error research is access to parts with well-defined performance metrics that can be readily applied in vastly different contexts with predictable effects. As the field now stands, research depends greatly on analytical tools that assay target molecules, transcripts, proteins, and metabolites across different hosts and pathways. Screening technologies yield specific information for many thousands of strain variants, while deep omics analysis provides a systems-level view of the cell factory. Efforts focused on a combination of these analyses yield quantitative information of dynamic processes between parts and the host chassis that drive the next engineering steps. Overall, the data generated from these types of assays aid better decision-making at the design and strain construction stages to speed progress in metabolic engineering research.

  2. Metabolism and neurogenesis.

    Science.gov (United States)

    Knobloch, Marlen; Jessberger, Sebastian

    2017-02-01

    The generation of neurons in the developing and adult mammalian brain by neural stem/progenitor cells (NSPCs) depends on a tight control of NSPC activity and neuronal differentiation that is regulated by a plethora of intrinsic and extrinsic molecular cues. Besides well-studied morphogenic signaling pathways and transcriptional codes that govern the distinct developmental steps from the dividing NSPC to a functional neuron, a critical role of cellular metabolism to determine the functional properties of NSPCs and newborn neurons has been recently identified. Here, we review advances in our understanding of how metabolism affects NSPC behavior and subsequent neuronal differentiation and suggest how metabolism may serve as a common signal integrator to ensure life-long addition of new neurons in the mammalian brain.

  3. Circadian physiology of metabolism.

    Science.gov (United States)

    Panda, Satchidananda

    2016-11-25

    A majority of mammalian genes exhibit daily fluctuations in expression levels, making circadian expression rhythms the largest known regulatory network in normal physiology. Cell-autonomous circadian clocks interact with daily light-dark and feeding-fasting cycles to generate approximately 24-hour oscillations in the function of thousands of genes. Circadian expression of secreted molecules and signaling components transmits timing information between cells and tissues. Such intra- and intercellular daily rhythms optimize physiology both by managing energy use and by temporally segregating incompatible processes. Experimental animal models and epidemiological data indicate that chronic circadian rhythm disruption increases the risk of metabolic diseases. Conversely, time-restricted feeding, which imposes daily cycles of feeding and fasting without caloric reduction, sustains robust diurnal rhythms and can alleviate metabolic diseases. These findings highlight an integrative role of circadian rhythms in physiology and offer a new perspective for treating chronic diseases in which metabolic disruption is a hallmark.

  4. Endocannabinoids and Metabolic Disorders.

    Science.gov (United States)

    Gatta-Cherifi, Blandine; Cota, Daniela

    2015-01-01

    The endocannabinoid system (ECS) is known to exert regulatory control on essentially every aspect related to the search for, and the intake, metabolism and storage of calories, and consequently it represents a potential pharmacotherapeutic target for obesity, diabetes and eating disorders. While the clinical use of the first generation of cannabinoid type 1 (CB(1)) receptor blockers has been halted due to the psychiatric side effects that their use occasioned, recent research in animals and humans has provided new knowledge on the mechanisms of actions of the ECS in the regulation of eating behavior, energy balance, and metabolism. In this review, we discuss these recent advances and how they may allow targeting the ECS in a more specific and selective manner for the future development of therapies against obesity, metabolic syndrome, and eating disorders.

  5. Nitrile Metabolizing Yeasts

    Science.gov (United States)

    Bhalla, Tek Chand; Sharma, Monica; Sharma, Nitya Nand

    Nitriles and amides are widely distributed in the biotic and abiotic components of our ecosystem. Nitrile form an important group of organic compounds which find their applications in the synthesis of a large number of compounds used as/in pharmaceutical, cosmetics, plastics, dyes, etc>. Nitriles are mainly hydro-lyzed to corresponding amide/acid in organic chemistry. Industrial and agricultural activities have also lead to release of nitriles and amides into the environment and some of them pose threat to human health. Biocatalysis and biotransformations are increasingly replacing chemical routes of synthesis in organic chemistry as a part of ‘green chemistry’. Nitrile metabolizing organisms or enzymes thus has assumed greater significance in all these years to convert nitriles to amides/ acids. The nitrile metabolizing enzymes are widely present in bacteria, fungi and yeasts. Yeasts metabolize nitriles through nitrilase and/or nitrile hydratase and amidase enzymes. Only few yeasts have been reported to possess aldoxime dehydratase. More than sixty nitrile metabolizing yeast strains have been hither to isolated from cyanide treatment bioreactor, fermented foods and soil. Most of the yeasts contain nitrile hydratase-amidase system for metabolizing nitriles. Transformations of nitriles to amides/acids have been carried out with free and immobilized yeast cells. The nitrilases of Torulopsis candida>and Exophiala oligosperma>R1 are enantioselec-tive and regiospecific respectively. Geotrichum>sp. JR1 grows in the presence of 2M acetonitrile and may have potential for application in bioremediation of nitrile contaminated soil/water. The nitrilase of E. oligosperma>R1 being active at low pH (3-6) has shown promise for the hydroxy acids. Immobilized yeast cells hydrolyze some additional nitriles in comparison to free cells. It is expected that more focus in future will be on purification, characterization, cloning, expression and immobilization of nitrile metabolizing

  6. Metabolic changes in malnutrition.

    Science.gov (United States)

    Emery, P W

    2005-10-01

    This paper is concerned with malnutrition caused by inadequate intake of all the major nutrients rather than deficiency diseases relating to a single micronutrient. Three common situations are recognised: young children in third world countries with protein-energy malnutrition; adults in the same countries who are chronically adapted to subsisting on marginally inadequate diets; and patients who become malnourished as a result of chronic diseases. In all these situations infectious diseases are often also present, and this complicates the interpretation of biochemical and physiological observations. The metabolic response to starvation is primarily concerned with maintaining a supply of water-soluble substrates to supply energy to the brain. Thus there is an initial rise in metabolic rate, reflecting gluconeogenic activity. As fasting progresses, gluconeogenesis is suppressed to minimise muscle protein breakdown and ketones become the main fuel for the brain. With chronic underfeeding the basal metabolic rate per cell appears to fall, but the mechanistic basis for this is not clear. The main adaptation to chronic energy deficiency is slow growth and low adult body size, although the reduction in energy requirement achieved by this is partially offset by the preservation of the more metabolically active organs at the expense of muscle, which has a lower metabolic rate. The interaction between malnutrition and the metabolic response to trauma has been studied using an animal model. The rise in energy expenditure and urinary nitrogen excretion following surgery were significantly attenuated in malnourished rats, suggesting that malnutrition impairs the ability of the body to mobilise substrates to support inflammatory and reparative processes. However, the healing process in wounded muscle remained unimpaired in malnutrition, suggesting that this process has a high biological priority.

  7. Hypothyroidism in metabolic syndrome

    Directory of Open Access Journals (Sweden)

    Sunil Kumar Kota

    2012-01-01

    Full Text Available Aim: Metabolic syndrome (MetS and hypothyroidism are well established forerunners of atherogenic cardiovascular disease. Considerable overlap occurs in the pathogenic mechanisms of atherosclerotic cardiovascular disease by metabolic syndrome and hypothyroidism. Insulin resistance has been studied as the basic pathogenic mechanism in metabolic syndrome. [1] This cross sectional study intended to assess thyroid function in patients with metabolic syndrome and to investigate the association between hypothyroidism and metabolic syndrome. Materials and Methods: One hundred patients with metabolic syndrome who fulfilled the National Cholesterol Education Program- Adult Treatment Panel (NCEP-ATP III criteria [ 3 out of 5 criteria positive namely blood pressure ≥ 130/85 mm hg or on antihypertensive medications, fasting plasma glucose > 100 mg/dl or on anti-diabetic medications, fasting triglycerides > 150 mg/dl, high density lipoprotein cholesterol (HDL-C 102 cms in men and 88 cms in women] were included in the study group. [2] Fifty patients who had no features of metabolic syndrome (0 out of 5 criteria for metabolic syndrome were included in the control group. Patients with liver disorders, renal disorders, congestive cardiac failure, pregnant women, patients on oral contraceptive pills, statins and other medications that alter thyroid functions and lipid levels and those who are under treatment for any thyroid related disorder were excluded from the study. Acutely ill patients were excluded taking into account sick euthyroid syndrome. Patients were subjected to anthropometry, evaluation of vital parameters, lipid and thyroid profile along with other routine laboratory parameters. Students t-test, Chi square test and linear regression, multiple logistic regression models were used for statistical analysis. P value < 0.05 was considered significant. Results: Of the 100 patients in study group, 55 were females (55% and 45 were males (45%. Of the 50

  8. Toxic and Metabolic Myelopathies.

    Science.gov (United States)

    Ramalho, Joana; Nunes, Renato Hoffmann; da Rocha, Antonio José; Castillo, Mauricio

    2016-10-01

    Myelopathy describes any neurologic deficit related to the spinal cord. It is most commonly caused by its compression by neoplasms, degenerative disc disease, trauma, or infection. Less common causes of myelopathy include spinal cord tumors, infection, inflammatory, neurodegenerative, vascular, toxic, and metabolic disorders. Conditions affecting the spinal cord must be recognized as early as possible to prevent progression that may lead to permanent disability. Biopsy is rarely performed, thus the diagnosis and management rely on patient׳s history, physical examination, laboratory results, and imaging findings. Here we review the clinical presentations, pathophysiological mechanisms, and magnetic resonance imaging findings of myelopathies related to metabolic or toxic etiologies.

  9. Metabolic Factors in Fatigue

    Institute of Scientific and Technical Information of China (English)

    Mark Hargreaves

    2006-01-01

    Increased non-oxidative and oxidative ATP production via metabolic pathways in skeletal muscle is essential for the maintenance of force and power production during exercise. However, substrate depletion and accumulation of metabolic byproducts are potential causes of fatigue. Reduced PCr availability can limit power production during sprint exercise, whereas carbohydrate depletion is a major limitation to endurance performance. During sprint exercise increased Pi and H+ may contribute to fatigue, and during prolonged strenuous exercise, the accumulation of NH3, reactive oxygen species, and heat can limit performance. Appropriate training programs and nutritional interventions are potential strategies to enhance fatigue resistance and exercise performance.

  10. Sleep and Metabolism: An Overview

    Directory of Open Access Journals (Sweden)

    Sunil Sharma

    2010-01-01

    Full Text Available Sleep and its disorders are increasingly becoming important in our sleep deprived society. Sleep is intricately connected to various hormonal and metabolic processes in the body and is important in maintaining metabolic homeostasis. Research shows that sleep deprivation and sleep disorders may have profound metabolic and cardiovascular implications. Sleep deprivation, sleep disordered breathing, and circadian misalignment are believed to cause metabolic dysregulation through myriad pathways involving sympathetic overstimulation, hormonal imbalance, and subclinical inflammation. This paper reviews sleep and metabolism, and how sleep deprivation and sleep disorders may be altering human metabolism.

  11. Metabolism at Evolutionary Optimal States

    Directory of Open Access Journals (Sweden)

    Iraes Rabbers

    2015-06-01

    Full Text Available Metabolism is generally required for cellular maintenance and for the generation of offspring under conditions that support growth. The rates, yields (efficiencies, adaptation time and robustness of metabolism are therefore key determinants of cellular fitness. For biotechnological applications and our understanding of the evolution of metabolism, it is necessary to figure out how the functional system properties of metabolism can be optimized, via adjustments of the kinetics and expression of enzymes, and by rewiring metabolism. The trade-offs that can occur during such optimizations then indicate fundamental limits to evolutionary innovations and bioengineering. In this paper, we review several theoretical and experimental findings about mechanisms for metabolic optimization.

  12. Macrophage Polarization in Metabolism and Metabolic Disease

    Directory of Open Access Journals (Sweden)

    Anna Meiliana

    2013-08-01

    Full Text Available BACKGROUND: Obesity is now recognized as the main cause of the worldwide epidemic of type 2 diabetes. Obesity-associated chronic inflammation is a contributing key factor for type 2 diabetes and cardiovascular disease. Numbers of studies have clearly demonstrated that the immune system and metabolism are highly integrated. CONTENT: Macrophages are an essential component of innate immunity and play a central role in inflammation and host defense. Moreover, these cells have homeostatic functions beyond defense, including tissue remodeling in ontogenesis and orchestration of metabolic functions. Diversity and plasticity are hallmarks of cells of the monocyte-macrophage lineage. In response to interferons (IFNs, toll-like receptor (TLR, or interleukin (IL-4/IL-13 signals, macrophages undergo M1 (classical or M2 (alternative activation. Progress has now been made in defining the signaling pathways, transcriptional networks, and epigenetic mechanisms underlying M1, M2 or M2-like polarized activation. SUMMARY: In response to various signals, macrophages may undergo classical M1 activation (stimulated by TLR ligands and IFN-γ or alternative M2 activation (stimulated by IL-4/IL-13; these states mirror the T helper (Th1–Th2 polarization of T cells. Pathology is frequently associated with dynamic changes in macrophage activation, with classically activated M1 cells implicate in initiating and sustaining inflammation, meanwhile M2 or M2-like activated cells associated with resolution or smoldering chronic inflammation. Identification of the mechanisms and molecules that are associated with macrophage plasticity and polarized activation provides a basis for macrophage centered diagnostic and therapeutic strategies. KEYWORDS: obesity, adipose tissue, inflammation, macrophage polarization.

  13. ENDOCRINOLOGY AND METABOLISM

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    2006162 Change of vascular endothelial function in patients with disorders of glucose metabolism. ZHANG Songjing,(张松菁),et al. Dept Endocrinol ,1st Hosp, Fujian Med Univ ,Fuzhou 350005. Chin J Endocrinol Metab 2006;22(1): 11 - 14. Objective: To observe the changes of the endothelium - dependent vasodilation ( EDF) and serum superoxide

  14. Sterol metabolism of insects

    NARCIS (Netherlands)

    Ritter, F.J.; Wientjens, W.H.J.M.

    1967-01-01

    This article surveys the present knowledge of the sterol metabolism of insects. It is emphasized that a high degree of purity of the dietary sterols and the climination of the influence of symbionts are essential to present ambiguity in interpreting results. It is pointed out that a sharp distinctio

  15. Lipoprotein(a) metabolism

    Science.gov (United States)

    Lipoprotein(a) [Lp(a)] is an atherogenic lipoprotein. The metabolism of this lipoprotein is still not well understood. It has long been known that the plasma concentration of Lp(a) is highly heritable, with its genetic determinants located in the apo(a) locus and regulating the rate of hepatic apo(a...

  16. Ghrelin and Metabolic Surgery

    Directory of Open Access Journals (Sweden)

    Dimitrios J. Pournaras

    2010-01-01

    Full Text Available Metabolic surgery is the most effective treatment for morbid obesity. Ghrelin has been implicated to play a role in the success of these procedures. Furthermore, these operations have been used to study the gut-brain axis. This article explores this interaction, reviewing the available data on changes in ghrelin levels after different surgical procedures.

  17. Methanogenesis: Syntrophic metabolism

    NARCIS (Netherlands)

    Sieber, J.R.; McInerney, M.J.; Plugge, C.M.; Schink, B.; Gunsales, R.P.

    2009-01-01

    "Water is life!" All active cellular systems require water as the medium and solvent of their metabolic activities. Hydrophobic compounds and structures, which tend to exclude water, though providing inter alia excellent sources of energy and a means of biological compartmentalization, present

  18. Glial metabolism of valine.

    Science.gov (United States)

    Murín, Radovan; Mohammadi, Ghasem; Leibfritz, Dieter; Hamprecht, Bernd

    2009-07-01

    The three essential amino acids, valine, leucine and isoleucine, constitute the group of branched-chain amino acids (BCAAs). BCAAs are rapidly taken up into the brain parenchyma, where they serve several distinct functions including that as fuel material in brain energy metabolism. As one function of astrocytes is considered the production of fuel molecules that support the energy metabolism of adjacent neural cells in brain. Astroglia-rich primary cultures (APC) were shown to rapidly dispose of the BCAAs, including valine, contained in the culture medium. While the metabolisms of leucine and isoleucine by APC have already been studied in detail, some aspects of valine metabolism remained to be determined. Therefore, in the present study an NMR analysis was performed to identify the (13)C-labelled metabolites that are generated by APC during catabolism of [U-(13)C]valine and that are subsequently released into the incubation medium. The results presented show that APC (1) are potently disposing of the valine contained in the incubation medium; (2) are capable of degrading valine to the tricarboxylic acid (TCA) cycle member succinyl-CoA; and (3) release into the extracellular milieu valine catabolites and compounds generated from them such as [U-(13)C]2-oxoisovalerate, [U-(13)C]3-hydroxyisobutyrate, [U-(13)C]2-methylmalonate, [U-(13)C]isobutyrate, and [U-(13)C]propionate as well as several TCA cycle-dependent metabolites including lactate.

  19. Prebiotic metabolic networks?

    OpenAIRE

    Luisi, Pier Luigi

    2014-01-01

    A prebiotic origin of metabolism has been proposed as one of several scenarios for the origin of life. In their recent work, Ralser and colleagues (Keller et al, 2014) observe an enzyme‐free, metabolism‐like reaction network under conditions reproducing a possible prebiotic environment.

  20. Sucrose Metabolism in Plastids

    NARCIS (Netherlands)

    Gerrits, N.; Turk, S.C.H.J.; Dun, van K.P.M.; Hulleman, H.D.; Visser, R.G.F.; Weisbeek, P.J.; Smeekens, S.C.M.

    2001-01-01

    The question whether sucrose (Suc) is present inside plastids has been long debated. Low Suc levels were reported to be present inside isolated chloroplasts, but these were argued to be artifacts of the isolation procedures used. We have introduced Suc-metabolizing enzymes in plastids and our experi

  1. Prebiotic metabolic networks?

    OpenAIRE

    2014-01-01

    A prebiotic origin of metabolism has been proposed as one of several scenarios for the origin of life. In their recent work, Ralser and colleagues (Keller et al, 2014) observe an enzyme‐free, metabolism‐like reaction network under conditions reproducing a possible prebiotic environment.

  2. Methanogenesis: Syntrophic metabolism

    NARCIS (Netherlands)

    Sieber, J.R.; McInerney, M.J.; Plugge, C.M.; Schink, B.; Gunsales, R.P.

    2009-01-01

    "Water is life!" All active cellular systems require water as the medium and solvent of their metabolic activities. Hydrophobic compounds and structures, which tend to exclude water, though providing inter alia excellent sources of energy and a means of biological compartmentalization, present probl

  3. Rethinking Guard Cell Metabolism.

    Science.gov (United States)

    Santelia, Diana; Lawson, Tracy

    2016-11-01

    Stomata control gaseous fluxes between the internal leaf air spaces and the external atmosphere and, therefore, play a pivotal role in regulating CO2 uptake for photosynthesis as well as water loss through transpiration. Guard cells, which flank the stomata, undergo adjustments in volume, resulting in changes in pore aperture. Stomatal opening is mediated by the complex regulation of ion transport and solute biosynthesis. Ion transport is exceptionally well understood, whereas our knowledge of guard cell metabolism remains limited, despite several decades of research. In this review, we evaluate the current literature on metabolism in guard cells, particularly the roles of starch, sucrose, and malate. We explore the possible origins of sucrose, including guard cell photosynthesis, and discuss new evidence that points to multiple processes and plasticity in guard cell metabolism that enable these cells to function effectively to maintain optimal stomatal aperture. We also discuss the new tools, techniques, and approaches available for further exploring and potentially manipulating guard cell metabolism to improve plant water use and productivity. © 2016 American Society of Plant Biologists. All Rights Reserved.

  4. Metabolic Syndrome (For Parents)

    Science.gov (United States)

    ... the road to heart disease and type 2 diabetes . Kids with metabolic syndrome have at least three of ... previous 1 • 2 • 3 • 4 For Teens For Kids For Parents MORE ON THIS TOPIC Diabetes Center Acanthosis Nigricans Overweight and Obesity Can Diabetes ...

  5. Diversified glucosinolate metabolism

    DEFF Research Database (Denmark)

    Frisch, Tina; Motawie, Mohammed Saddik; Olsen, Carl Erik;

    2015-01-01

    were biosynthesized from methionine. The biosynthesis of alliarinoside was shown not to bifurcate from sinigrin biosynthesis at the oxime level in contrast to the general scheme for hydroxynitrile glucoside biosynthesis. Instead, the aglucon of alliarinoside was formed from metabolism of sinigrin...

  6. Dysregulated metabolism contributes to oncogenesis

    Science.gov (United States)

    Hirschey, Matthew D.; DeBerardinis, Ralph J.; Diehl, Anna Mae E.; Drew, Janice E.; Frezza, Christian; Green, Michelle F.; Jones, Lee W.; Ko, Young H.; Le, Anne; Lea, Michael A.; Locasale, Jason W.; Longo, Valter D.; Lyssiotis, Costas A.; McDonnell, Eoin; Mehrmohamadi, Mahya; Michelotti, Gregory; Muralidhar, Vinayak; Murphy, Michael P.; Pedersen, Peter L.; Poore, Brad; Raffaghello, Lizzia; Rathmell, Jeffrey C.; Sivanand, Sharanya; Vander Heiden, Matthew G.; Wellen, Kathryn E.

    2015-01-01

    Cancer is a disease characterized by unrestrained cellular proliferation. In order to sustain growth, cancer cells undergo a complex metabolic rearrangement characterized by changes in metabolic pathways involved in energy production and biosynthetic processes. The relevance of the metabolic transformation of cancer cells has been recently included in the updated version of the review “Hallmarks of Cancer”, where the dysregulation of cellular metabolism was included as an emerging hallmark. While several lines of evidence suggest that metabolic rewiring is orchestrated by the concerted action of oncogenes and tumor suppressor genes, in some circumstances altered metabolism can play a primary role in oncogenesis. Recently, mutations of cytosolic and mitochondrial enzymes involved in key metabolic pathways have been associated with hereditary and sporadic forms of cancer. Together, these results suggest that aberrant metabolism, once seen just as an epiphenomenon of oncogenic reprogramming, plays a key role in oncogenesis with the power to control both genetic and epigenetic events in cells. In this review, we discuss the relationship between metabolism and cancer, as part of a larger effort to identify a broad-spectrum of therapeutic approaches. We focus on major alterations in nutrient metabolism and the emerging link between metabolism and epigenetics. Finally, we discuss potential strategies to manipulate metabolism in cancer and tradeoffs that should be considered. More research on the suite of metabolic alterations in cancer holds the potential to discover novel approaches to treat it. PMID:26454069

  7. Hypoxamirs and Mitochondrial Metabolism

    Science.gov (United States)

    Cottrill, Katherine A.; Chan, Stephen Y.

    2014-01-01

    Abstract Significance: Chronic hypoxia can drive maladaptive responses in numerous organ systems, leading to a multitude of chronic mammalian diseases. Oxygen homeostasis is intimately linked with mitochondrial metabolism, and dysfunction in these systems can combine to form the backbone of hypoxic-ischemic injury in multiple tissue beds. Increased appreciation of the crucial roles of hypoxia-associated miRNA (hypoxamirs) in metabolism adds a new dimension to our understanding of the regulation of hypoxia-induced disease. Recent Advances: Myriad factors related to glycolysis (e.g., aldolase A and hexokinase II), tricarboxylic acid cycle function (e.g., glutaminase and iron-sulfur cluster assembly protein 1/2), and apoptosis (e.g., p53) have been recently implicated as targets of hypoxamirs. In addition, several hypoxamirs have been implicated in the regulation of the master transcription factor of hypoxia, hypoxia-inducible factor-1α, clarifying how the cellular program of hypoxia is sustained and resolved. Critical Issues: Central to the discussion of metabolic change in hypoxia is the Warburg effect, a shift toward anaerobic metabolism that persists after normal oxygen levels have been restored. Many newly discovered targets of hypoxia-driven microRNA converge on pathways known to be involved in this pathological phenomenon and the apoptosis-resistant phenotype associated with it. Future Directions: The often synergistic functions of miRNA may make them ideal therapeutic targets. The use of antisense inhibitors is currently being considered in diseases in which hypoxia and metabolic dysregulation predominate. In addition, exploration of pleiotripic miRNA functions will likely continue to offer unique insights into the mechanistic relationships of their downstream target pathways and associated hypoxic phenotypes. Antioxid. Redox Signal. 21, 1189–1201. PMID:24111795

  8. Adaptation of a mixed culture of acidophiles for a tank biooxidation of refractory gold concentrates containing a high concentration of arsenic.

    Science.gov (United States)

    Hong, Jeongsik; Silva, Rene A; Park, Jeonghyun; Lee, Eunseong; Park, Jayhyun; Kim, Hyunjung

    2016-05-01

    We adapted a mixed culture of acidophiles to high arsenic concentrations to confirm the possibility of achieving more than 70% biooxidation of refractory gold concentrates containing high arsenic (As) concentration. The biooxidation process was applied to refractory gold concentrates containing approximately 139.67 g/kg of total As in a stirred tank reactor using an adapted mixed culture of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans. The percentage of the biooxidation process was analyzed based on the total As removal efficiency. The As removal was monitored by inductively coupled plasma (ICP) analysis, conducted every 24 h. The results obtained with the adapted culture were compared with the percentage of biooxidation obtained with a non-adapted mixed culture of A. ferrooxidans and A. thiooxidans, and with their respective pure cultures. The percentages of biooxidation obtained during 358 h of reaction were 72.20%, 38.20%, 27.70%, and 11.45% for adapted culture, non-adapted culture, and pure cultures of A. thiooxidans and A. ferrooxidans, respectively. The adapted culture showed a peak maximum percentage of biooxidation of 77% at 120 h of reaction, confirming that it is possible to obtain biooxidation percentages over 70% in gold concentrates containing high As concentrations.

  9. PROPERTIES OF NEW STRAINS CHEMOLITHOTROPHIC BACTERIA ISOLATED FROM INDUSTRIAL SUBSTRATES

    Directory of Open Access Journals (Sweden)

    I. A.

    2015-12-01

    Full Text Available The purpose of the research was determination of strains Acidithiobacillus ferrooxidans MFLv37 and Acidithiobacillus ferrooxidans MFLad27, isolated from aboriginal consortium of coal beneficiation dumps and fly ash from coal combustion, resistance to heavy metals, forming part of these waste, as well as adaption ability of the strains to new substrates. New strains increased resistance to heavy metal ions as compared to A. ferrooxidans standard and collection strains is found; minimal inhibitory concentrations of heavy and toxic metals are determined; a number of metals that have negative impact on growth of isolated cultures are identified. It is shown that the minimal metals concentrations, at which strains growth still happens, are several times higher than their concentrations in technogenic waste. It has been established that isolated strains differed in their ability to adapt, as well as in growth rate and substrates oxidation. This is due to the specific conditions of microbiocenoses formation in making and further storage of rock dumps and fly ash, whereof the appropriate strains are isolated. The investigations indicate the necessity in directional selection of strains that are resistant to the toxic compounds and are able to oxidize various mineral substrates, as well as in their adaptation to new substrates for the extraction of heavy metals.

  10. Analysis of early bacterial communities on volcanic deposits on the island of Miyake (Miyake-jima), Japan: a 6-year study at a fixed site.

    Science.gov (United States)

    Fujimura, Reiko; Sato, Yoshinori; Nishizawa, Tomoyasu; Nanba, Kenji; Oshima, Kenshiro; Hattori, Masahira; Kamijo, Takashi; Ohta, Hiroyuki

    2012-01-01

    Microbial colonization on new terrestrial substrates represents the initiation of new soil ecosystem formation. In this study, we analyzed early bacterial communities growing on volcanic ash deposits derived from the 2000 Mount Oyama eruption on the island of Miyake (Miyake-jima), Japan. A site was established in an unvegetated area near the summit and investigated over a 6-year period from 2003 to 2009. Collected samples were acidic (pH 3.0-3.6), did not utilize any organic substrates in ECO microplate assays (Biolog), and harbored around 106 cells (g dry weight)(-1) of autotrophic Fe(II) oxidizers by most-probable-number (MPN) counts. Acidithiobacillus ferrooxidans, Acidithiobacillus ferrivorans, and the Leptospirillum groups I, II and III were found to be abundant in the deposits by clone library analysis of bacterial 16S rRNA genes. The numerical dominance of Acidithiobacillus ferrooxidans was also supported by analysis of the gene coding for the large subunit of the form I ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO). Comparing the 16S rRNA gene clone libraries from samples differing in age, shifts in Fe(II)-oxidizing populations seemed to occur with deposit aging. The detection of known 16S rRNA gene sequences from Fe(III)-reducing acidophiles promoted us to propose the acidity-driven iron cycle for the early microbial ecosystem on the deposit.

  11. SIRT1 and energy metabolism

    Institute of Scientific and Technical Information of China (English)

    Xiaoling Li

    2013-01-01

    Sirtuin 1 (SIRT1) is the most conserved mammalian NAD+-dependent protein deacetylase that has emerged as a key metabolic sensor in various metabolic tissues.In response to different environmental stimuli,SIRT1 directly links the cellular metabolic status to the chromatin structure and the regulation of gene expression,thereby modulating a variety of cellular processes such as energy metabolism and stress response.Recent studies have shown that SIRT1 controls both glucose and lipid metabolism in the liver,promotes fat mobilization and stimulates brown remodeling of the white fat in white adipose tissue,controls insulin secretion in the pancreas,senses nutrient availability in the hypothalamus,influences obesityinduced inflammation in macrophages,and modulates the activity of circadian clock in metabolic tissues.This review focuses on the role of SIRT1 in regulating energy metabolism at different metabolic tissues.

  12. How Is Metabolic Syndrome Treated?

    Science.gov (United States)

    ... page from the NHLBI on Twitter. How Is Metabolic Syndrome Treated? Heart-healthy lifestyle changes are the first line of treatment for metabolic syndrome. If heart-healthy lifestyle changes aren’t enough, ...

  13. Autophagy research: Lessons from metabolism

    NARCIS (Netherlands)

    A.J. Meijer

    2009-01-01

    Autophagy research continues to expand exponentially. Clearly autophagy and metabolism are intimately connected; however, the rapid expansion of research into this topic inevitably brings the risk that important basic knowledge of metabolism will be overlooked when considering experimental data. Unf

  14. Metabolic Syndrome, Androgens, and Hypertension

    OpenAIRE

    Moulana, Mohadetheh; Lima, Roberta; Reckelhoff, Jane F.

    2011-01-01

    Obesity is one of the constellation of factors that make up the definition of the metabolic syndrome. Metabolic syndrome is also associated with insulin resistance, dyslipidemia, hypertriglyceridemia, and type 2 diabetes mellitus. The presence of obesity and metabolic syndrome in men and women is also associated with increased risk of cardiovascular disease and hypertension. In men, obesity and metabolic syndrome are associated with reductions in testosterone levels. In women, obesity and met...

  15. Metabolic syndrome and professional aptitude

    OpenAIRE

    Dorota Rębak; Edyta Suliga; Stanisław Głuszek

    2016-01-01

    The development of civilisation has resulted in a growing problem of metabolic diseases, including metabolic syndrome. Scientific studies show that this disease is an epidemic of the 21st century. Metabolic syndrome is a collection of mutually related metabolic factors, such as obesity, impaired glucose tolerance, lipid disorders, arterial hypertension, and pro-inflammatory and prothrombotic state, increasing the risk of the development of atherosclerosis and type 2 diabetes, and their cardio...

  16. Metabolism of hyperthermophiles.

    Science.gov (United States)

    Schönheit, P; Schäfer, T

    1995-01-01

    Hyperthermophiles are characterized by a temperature optimum for growth between 80 and 110°C. They are considered to represent the most ancient phenotype of living organisms and thus their metabolic design might reflect the situation at an early stage of evolution. Their modes of metabolism are diverse and include chemolithoautotrophic and chemoorganoheterotrophic. No extant phototrophic hyperthermophiles are known. Lithotrophic energy metabolism is mostly anaerobic or microaerophilic and based on the oxidation of H2 or S coupled to the reduction of S, SO inf4 (sup2-) , CO2 and NO inf3 (sup-) but rarely to O2. the substrates are derived from volcanic activities in hyperthermophilic habitats. The lithotrophic energy metabolism of hyperthermophiles appears to be similar to that of mesophiles. Autotrophic CO2 fixation proceeds via the reductive citric acid cycle, considered to be one of the first metabolic cycles, and via the reductive acetyl-CoA/carbon monoxide dehydrogenase pathway. The Calvin cycle has not been found in hyperthermophiles (or any Archaea). Organotrophic metabolism mainly involves peptides and sugars as substrates, which are either oxidized to CO2 by external electron acceptors or fermented to acetate and other products. Sugar catabolism in hyperthermophiles involves non-phosphorylated versions of the Entner-Doudoroff pathway and modified versions of the Embden-Meyerhof pathway. The 'classical' Embden-Meyerhof pathway is present in hyperthermophilic Bacteria (Thermotoga) but not in Archaea. All hyperthermophiles (and Archaea) tested so far utilize pyruvate:ferredoxin oxidoreductase for acetyl-CoA formation from pyruvate. Acetyl-CoA oxidation in anaerobic sulphur-reducing and aerobic hyperthermophiles proceeds via the citric acid cycle; in the hyperthermophilic sulphate-reducer Archaeoglobus an oxidative acetyl-CoA/carbon monoxide dehydrogenase pathway is operative. Acetate formation from acetyl-CoA in Archaea, including hyperthermophiles, is

  17. Macrophages and Iron Metabolism.

    Science.gov (United States)

    Soares, Miguel P; Hamza, Iqbal

    2016-03-15

    Iron is a transition metal that due to its inherent ability to exchange electrons with a variety of molecules is essential to support life. In mammals, iron exists mostly in the form of heme, enclosed within an organic protoporphyrin ring and functioning primarily as a prosthetic group in proteins. Paradoxically, free iron also has the potential to become cytotoxic when electron exchange with oxygen is unrestricted and catalyzes the production of reactive oxygen species. These biological properties demand that iron metabolism is tightly regulated such that iron is available for core biological functions while preventing its cytotoxic effects. Macrophages play a central role in establishing this delicate balance. Here, we review the impact of macrophages on heme-iron metabolism and, reciprocally, how heme-iron modulates macrophage function.

  18. Neuroendocrine control of metabolism.

    Science.gov (United States)

    Kuliczkowska-Plaksej, J; Milewicz, A; Jakubowska, J

    2012-03-01

    Metabolism is controlled through homeostatic system consisting of central centers, gut hormones, hormones from adipose tissue and the other hormonal axes. This cooperation is based on cross-talk between central and peripheral signals. Among them the hypothalamus plays a crucial role, with interconnected nuclei forming neuronal circuits. Other regions in the brain, such as the brain stem, the endocannabinoid system, the vagal afferents, are also involved in energy balance. The second component is peripheral source of signals--the gastrointestinal tract hormones. Additionally, adipokines from adipose tissue, thyrotropic, gonadotropic and somatotropic axes play a role in energy homeostasis. Knowledge about all components of this neuroendocrine circuit will be helpful in developing novel therapeutic approaches against the metabolic syndrome and its components.

  19. Autophagy, Metabolism, and Cancer.

    Science.gov (United States)

    White, Eileen; Mehnert, Janice M; Chan, Chang S

    2015-11-15

    Macroautophagy (autophagy hereafter) captures intracellular proteins and organelles and degrades them in lysosomes. The degradation breakdown products are released from lysosomes and recycled into metabolic and biosynthetic pathways. Basal autophagy provides protein and organelle quality control by eliminating damaged cellular components. Starvation-induced autophagy recycles intracellular components into metabolic pathways to sustain mitochondrial metabolic function and energy homeostasis. Recycling by autophagy is essential for yeast and mammals to survive starvation through intracellular nutrient scavenging. Autophagy suppresses degenerative diseases and has a context-dependent role in cancer. In some models, cancer initiation is suppressed by autophagy. By preventing the toxic accumulation of damaged protein and organelles, particularly mitochondria, autophagy limits oxidative stress, chronic tissue damage, and oncogenic signaling, which suppresses cancer initiation. This suggests a role for autophagy stimulation in cancer prevention, although the role of autophagy in the suppression of human cancer is unclear. In contrast, some cancers induce autophagy and are dependent on autophagy for survival. Much in the way that autophagy promotes survival in starvation, cancers can use autophagy-mediated recycling to maintain mitochondrial function and energy homeostasis to meet the elevated metabolic demand of growth and proliferation. Thus, autophagy inhibition may be beneficial for cancer therapy. Moreover, tumors are more autophagy-dependent than normal tissues, suggesting that there is a therapeutic window. Despite these insights, many important unanswered questions remain about the exact mechanisms of autophagy-mediated cancer suppression and promotion, how relevant these observations are to humans, and whether the autophagy pathway can be modulated therapeutically in cancer. See all articles in this CCR Focus section, "Cell Death and Cancer Therapy."

  20. Epigenetics and Cellular Metabolism

    OpenAIRE

    Wenyi Xu; Fengzhong Wang; Zhongsheng Yu; Fengjiao Xin

    2016-01-01

    Living eukaryotic systems evolve delicate cellular mechanisms for responding to various environmental signals. Among them, epigenetic machinery (DNA methylation, histone modifications, microRNAs, etc.) is the hub in transducing external stimuli into transcriptional response. Emerging evidence reveals the concept that epigenetic signatures are essential for the proper maintenance of cellular metabolism. On the other hand, the metabolite, a main environmental input, can also influence the proce...

  1. Metabolism and Brain Cancer

    OpenAIRE

    Suely Kazue Nagahashi Marie; Sueli Mieko Oba Shinjo

    2011-01-01

    Cellular energy metabolism is one of the main processes affected during the transition from normal to cancer cells, and it is a crucial determinant of cell proliferation or cell death. As a support for rapid proliferation, cancer cells choose to use glycolysis even in the presence of oxygen (Warburg effect) to fuel macromolecules for the synthesis of nucleotides, fatty acids, and amino acids for the accelerated mitosis, rather than fuel the tricarboxylic acid cycle and oxidative phosphorylati...

  2. Analytics for metabolic engineering

    Directory of Open Access Journals (Sweden)

    Christopher J Petzold

    2015-09-01

    Full Text Available Realizing the promise of metabolic engineering has been slowed by challenges related to moving beyond proof-of-concept examples to robust and economically viable systems. Key to advancing metabolic engineering beyond trial-and-error research is access to parts with well-defined performance metrics that can be readily applied in vastly different contexts with predictable effects. As the field now stands, research depends greatly on analytical tools that assay target molecules, transcripts, proteins, and metabolites across different hosts and pathways. Screening technologies yield specific information for many thousands of strain variants while deep omics analysis provide a systems-level view of the cell factory. Efforts focused on a combination of these analyses yield quantitative information of dynamic processes between parts and the host chassis that drive the next engineering steps. Overall, the data generated from these types of assays aid better decision-making at the design and strain construction stages to speed progress in metabolic engineering research.

  3. Genetics of metabolic syndrome.

    Science.gov (United States)

    Stančáková, Alena; Laakso, Markku

    2014-12-01

    Metabolic syndrome (MetS) is a cluster of metabolic traits associated with an increased risk of cardiovascular disease and type 2 diabetes mellitus. Central obesity and insulin resistance are thought to play key roles in the pathogenesis of the MetS. The MetS has a significant genetic component, and therefore linkage analysis, candidate gene approach, and genome-wide association (GWA) studies have been applied in the search of gene variants for the MetS. A few variants have been identified, located mostly in or near genes regulating lipid metabolism. GWA studies for the individual components of the MetS have reported several loci having pleiotropic effects on multiple MetS-related traits. Genetic studies have provided so far only limited evidence for a common genetic background of the MetS. Epigenetic factors (DNA methylation and histone modification) are likely to play important roles in the pathogenesis of the MetS, and they might mediate the effects of environmental exposures on the risk of the MetS. Further research is needed to clarify the role of genetic variation and epigenetic mechanisms in the development of the MetS.

  4. Analytics for Metabolic Engineering

    Science.gov (United States)

    Petzold, Christopher J.; Chan, Leanne Jade G.; Nhan, Melissa; Adams, Paul D.

    2015-01-01

    Realizing the promise of metabolic engineering has been slowed by challenges related to moving beyond proof-of-concept examples to robust and economically viable systems. Key to advancing metabolic engineering beyond trial-and-error research is access to parts with well-defined performance metrics that can be readily applied in vastly different contexts with predictable effects. As the field now stands, research depends greatly on analytical tools that assay target molecules, transcripts, proteins, and metabolites across different hosts and pathways. Screening technologies yield specific information for many thousands of strain variants, while deep omics analysis provides a systems-level view of the cell factory. Efforts focused on a combination of these analyses yield quantitative information of dynamic processes between parts and the host chassis that drive the next engineering steps. Overall, the data generated from these types of assays aid better decision-making at the design and strain construction stages to speed progress in metabolic engineering research. PMID:26442249

  5. Dysregulated lipid metabolism in cancer

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Alteration of lipid metabolism has been increasingly recognized as a hallmark of cancer cells. The changes of expression and activity of lipid metabolizing enzymes are directly regulated by the activity of oncogenic signals. The dependence of tumor cells on the dysregulated lipid metabolism suggests that proteins involved in this process are excellent chemotherapeutic targets for cancer treatment. There are currently several drugs under development or in clinical trials that are based on specifically targeting the altered lipid metabolic pathways in cancer cells. Further understanding of dysregulated lipid metabolism and its associated signaling pathways will help us to better design efficient cancer therapeutic strategy.

  6. Metabolic pathways of trichothecenes.

    Science.gov (United States)

    Wu, Qinghua; Dohnal, Vlastimil; Huang, Lingli; Kuca, Kamil; Yuan, Zonghui

    2010-05-01

    Trichothecenes are a group of mycotoxins mainly produced by the fungi of Fusarium genus. Consumers are particularly concerned over the toxicity and food safety of trichothecenes and their metabolites from food-producing animals. The metabolism of T-2 toxin, deoxynivalenol (DON), nivalenol (NIV), fusarenon-X (FX), diacetoxyscirpenol (DAS), 3-acetyldeoxy-nivalenol (3-aDON), and 15-acetyldeoxynivalenol (15-aDON) in rodents, swine, ruminants, poultry, and humans are reviewed in this article. Metabolic pathways of these mycotoxins are very different. The major metabolic pathways of T-2 toxin in animals are hydrolysis, hydroxylation, de-epoxidation, and conjugation. After being transformed to HT-2 toxin, it undergoes further hydroxylation at C-3' to yield 3'-hydroxy-HT-2 toxin, which is considered as an activation pathway, whereas transformation from T-2 to T-2 tetraol is an inactivation pathway in animals. The typical metabolites of T-2 toxin in animals are HT-2 toxin, T-2 triol, T-2 tetraol, neosolaniol (NEO), 3'-hydroxy-HT-2, and 3'-hydroxy-T-2, whereas HT-2 toxin is the main metabolite in humans. De-epoxidation is an important pathway for detoxification in animals. De-epoxy products, DOM-1, and de-epoxy-NIV are the main metabolites of DON and NIV in most animals, respectively. However, the two metabolites are not found in humans. Deacetyl can occur rapidly on the acetyl derivatives, 3-aDON, 15-aDON, and FX. DAS is metabolized in animals to 15-monoacetoxyscirpenol (15-MAS) via C-4 deacetylation and then transformed to scirpentriol (SCP) via C-15 deacetylation. Finally, the epoxy is lost, yielding de-epoxy-SCP. De-epoxy-15-MAS is also the main metabolite of DAS. 15-MAS is the main metabolite in human skin. The review on the metabolism of trichothecenes will help one to well understand the fate of these toxins' future in animals and humans, as well as provide basic information for the risk assessment of them for food safety.

  7. Tumor Metabolism of Malignant Gliomas

    Energy Technology Data Exchange (ETDEWEB)

    Ru, Peng; Williams, Terence M.; Chakravarti, Arnab; Guo, Deliang, E-mail: deliang.guo@osumc.edu [Department of Radiation Oncology, Ohio State University Comprehensive Cancer Center & Arthur G James Cancer Hospital, Columbus, OH 43012 (United States)

    2013-11-08

    Constitutively activated oncogenic signaling via genetic mutations such as in the EGFR/PI3K/Akt and Ras/RAF/MEK pathways has been recognized as a major driver for tumorigenesis in most cancers. Recent insights into tumor metabolism have further revealed that oncogenic signaling pathways directly promote metabolic reprogramming to upregulate biosynthesis of lipids, carbohydrates, protein, DNA and RNA, leading to enhanced growth of human tumors. Therefore, targeting cell metabolism has become a novel direction for drug development in oncology. In malignant gliomas, metabolism pathways of glucose, glutamine and lipid are significantly reprogrammed. Moreover, molecular mechanisms causing these metabolic changes are just starting to be unraveled. In this review, we will summarize recent studies revealing critical gene alterations that lead to metabolic changes in malignant gliomas, and also discuss promising therapeutic strategies via targeting the key players in metabolic regulation.

  8. Tumor Metabolism of Malignant Gliomas

    Directory of Open Access Journals (Sweden)

    Deliang Guo

    2013-11-01

    Full Text Available Constitutively activated oncogenic signaling via genetic mutations such as in the EGFR/PI3K/Akt and Ras/RAF/MEK pathways has been recognized as a major driver for tumorigenesis in most cancers. Recent insights into tumor metabolism have further revealed that oncogenic signaling pathways directly promote metabolic reprogramming to upregulate biosynthesis of lipids, carbohydrates, protein, DNA and RNA, leading to enhanced growth of human tumors. Therefore, targeting cell metabolism has become a novel direction for drug development in oncology. In malignant gliomas, metabolism pathways of glucose, glutamine and lipid are significantly reprogrammed. Moreover, molecular mechanisms causing these metabolic changes are just starting to be unraveled. In this review, we will summarize recent studies revealing critical gene alterations that lead to metabolic changes in malignant gliomas, and also discuss promising therapeutic strategies via targeting the key players in metabolic regulation.

  9. Uncovering transcriptional regulation of metabolism by using metabolic network topology

    DEFF Research Database (Denmark)

    Patil, Kiran Raosaheb; Nielsen, Jens

    2005-01-01

    therefore developed an algorithm that is based on hypothesis-driven data analysis to uncover the transcriptional regulatory architecture of metabolic networks. By using information on the metabolic network topology from genome-scale metabolic reconstruction, we show that it is possible to reveal patterns...... in the metabolic network that follow a common transcriptional response. Thus, the algorithm enables identification of so-called reporter metabolites (metabolites around which the most significant transcriptional changes occur) and a set of connected genes with significant and coordinated response to genetic...... changes induced by complex regulatory mechanisms coordinating the activity of different metabolic pathways. It is difficult to map such global transcriptional responses by using traditional methods, because many genes in the metabolic network have relatively small changes at their transcription level. We...

  10. Gut microbiome and metabolic syndrome.

    Science.gov (United States)

    Mazidi, Mohsen; Rezaie, Peyman; Kengne, Andre Pascal; Mobarhan, Majid Ghayour; Ferns, Gordon A

    2016-01-01

    The gut microbiome contributes approximately 2kg of the whole body weight, and recent studies suggest that gut microbiota has a profound effect on human metabolism, potentially contributing to several features of the metabolic syndrome. Metabolic syndrome is defined by a clustering of metabolic disorders that include central adiposity with visceral fat accumulation, dyslipidemia, insulin resistance, dysglycemia and non-optimal blood pressure levels. Metabolic syndrome is associated with an increased risk of cardiovascular diseases and type 2 diabetes. It is estimated that around 20-25 percent of the world's adult population has metabolic syndrome. In this manuscript, we have reviewed the existing data linking gut microbiome with metabolic syndrome. Existing evidence from studies both in animals and humans support a link between gut microbiome and various components of metabolic syndrome. Possible pathways include involvement with energy homeostasis and metabolic processes, modulation of inflammatory signaling pathways, interferences with the immune system, and interference with the renin-angiotensin system. Modification of gut microbiota via prebiotics, probiotics or other dietary interventions has provided evidence to support a possible beneficial effect of interventions targeting gut microbiota modulation to treat components or complications of metabolic syndrome.

  11. Study on metabolic mechanisms of sodium thiosulfate by Thiobacillus Ferrooxidans and Thiobacillus Thiooxidans%氧化亚铁硫杆菌和氧化硫硫杆菌对硫代硫酸钠的代谢机理研究

    Institute of Scientific and Technical Information of China (English)

    沈镭; 张再利; 贾晓珊

    2006-01-01

    首先利用含硫的温泉水,经一系列培养、分离和纯化得到了氧化亚铁硫杆菌(T.f)和氧化硫硫杆菌(T.t).然后,将2种菌投加至一定浓度的硫代硫酸钠,观察2种菌在不同溶解氧浓度下的生长情况和溶液中各种硫化合物的浓度变化.结果表明,T.f利用硫代硫酸钠的速度比T.t快,生长周期也比T.t长,但单个T.f细胞的代谢能力较T.t差;T.f和T.t利用硫代硫酸钠的代谢产物主要为硫酸根离子、连四硫酸根离子、二氧化硫和单质硫.2种菌对硫代硫酸根离子的代谢主要通过4条途径进行.提高溶解氧浓度能显著加快2种菌对硫代硫酸钠的利用速度.

  12. Metabolic syndrome and pregnancy

    Directory of Open Access Journals (Sweden)

    A V Khromilev

    2014-06-01

    Full Text Available Metabolic syndrome (MS is a major problem of public health and health care system, with rising prevalence in the world. There is evidence that obesity, as the main component of MS, is strongly associated with the presence of gestational complications: fetal growth retardation, fetal macrosomia, gestational diabetes, preeclampsia, preterm delivery, stillbirth and perinatal death. The underlying mechanisms of this association are actively investigated nowadays. The importance of MS in pregnancy is also determined by the increase of the risk of venous trombosis.

  13. Metabolism and Endocrinology

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    2009039 A survey of glucose and lipid metabolism and concomitant diseases among inpatients in Guangdong province. TANG Kuanxiao(唐宽晓), et al. Dept Endocrinol, 3rd Affili Hosp, Sun Yat-sen Univ, Guangzhou 510630. Chin J Intern Med 2009;48(3):196-200. Objectives To investigate the epidemiological and clinical characteristics of dyslipidemia as well as its treatment and influence on accompanying diseases in impaired glucose status among inpatients. Methods A cross-sectional survey was conducted among the inpatients registered in ten university hospitals of Guangdong, China during the week before the Diabetes Day in 2004.

  14. Metabolic impact of shift work.

    Science.gov (United States)

    Zimberg, Ioná Zalcman; Fernandes Junior, Silvio A; Crispim, Cibele Aparecida; Tufik, Sergio; de Mello, Marco Tulio

    2012-01-01

    In developing countries, shift work represents a considerable contingent workforce. Recently, studies have shown that overweight and obesity are more prevalent in shift workers than day workers. In addition, shift work has been associated with a higher propensity for the development of many metabolic disorders, such as insulin resistance, diabetes, dislipidemias and metabolic syndrome. Recent data have pointed that decrease of the sleep time, desynchronization of circadian rhythm and alteration of environmental aspects are the main factors related to such problems. Shortened or disturbed sleep is among the most common health-related effects of shift work. The plausible physiological and biological mechanisms are related to the activation of the autonomic nervous system, inflammation, changes in lipid and glucose metabolism, and related changes in the risk for atherosclerosis, metabolic syndrome, and type II diabetes. The present review will discuss the impact of shift work on obesity and metabolic disorders and how disruption of sleep and circadian misalignment may contribute to these metabolic dysfunctions.

  15. Metabolic syndrome, androgens, and hypertension.

    Science.gov (United States)

    Moulana, Mohadetheh; Lima, Roberta; Reckelhoff, Jane F

    2011-04-01

    Obesity is one of the constellation of factors that make up the definition of the metabolic syndrome. Metabolic syndrome is also associated with insulin resistance, dyslipidemia, hypertriglyceridemia, and type 2 diabetes mellitus. The presence of obesity and metabolic syndrome in men and women is also associated with increased risk of cardiovascular disease and hypertension. In men, obesity and metabolic syndrome are associated with reductions in testosterone levels. In women, obesity and metabolic syndrome are associated with increases in androgen levels. In men, reductions in androgen levels are associated with inflammation, and androgen supplements reduce inflammation. In women, increases in androgens are associated with increases in inflammatory cytokines, and reducing androgens reduces inflammation. This review discusses the possibility that the effects of androgens on metabolic syndrome and its sequelae may differ between males and females.

  16. Metabolic syndrome, diet and exercise.

    Science.gov (United States)

    De Sousa, Sunita M C; Norman, Robert J

    2016-11-01

    Polycystic ovary syndrome (PCOS) is associated with a range of metabolic complications including insulin resistance (IR), obesity, dyslipidaemia, hypertension, obstructive sleep apnoea (OSA) and non-alcoholic fatty liver disease. These compound risks result in a high prevalence of metabolic syndrome and possibly increased cardiovascular (CV) disease. As the cardiometabolic risk of PCOS is shared amongst the different diagnostic systems, all women with PCOS should undergo metabolic surveillance though the precise approach differs between guidelines. Lifestyle interventions consisting of increased physical activity and caloric restriction have been shown to improve both metabolic and reproductive outcomes. Pharmacotherapy and bariatric surgery may be considered in resistant metabolic disease. Issues requiring further research include the natural history of PCOS-associated metabolic disease, absolute CV risk and comparative efficacy of lifestyle interventions.

  17. Metabolic topography of Parkinsonism

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Seung [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

    2007-04-15

    Parkinson's disease is one of the most frequent neurodegenerative diseases, which mainly affects the elderly. Parkinson's disease is often difficult to differentiate from atypical parkinson disorder such as progressive supranuclear palsy, multiple system atrophy, dementia with Lewy body, and corticobasal ganglionic degeneration, based on the clinical findings because of the similarity of phenotypes and lack of diagnostic markers. The accurate diagnosis of Parkinson's disease and atypical Parkinson disorders is not only important for deciding on treatment regimens and providing prognosis, but also it is critical for studies designed to investigate etiology and pathogenesis of parkinsonism and to develop new therapeutic strategies. Although degeneration of the nigrostriatal dopamine system results in marked loss of striatal dopamine content in most of the diseases causing parkinsonism, pathologic studies revealed different topographies of the neuronal cell loss in Parkinsonism. Since the regional cerebral glucose metabolism is a marker of integrated local synaptic activity and as such is sensitive to both direct neuronal/synaptic damage and secondary functional disruption at synapses distant from the primary site of pathology, and assessment of the regional cerebral glucose metabolism with F-18 FDG PET is useful in the differential diagnosis of parkinsonism and evaluating the pathophysiology of Parkinsonism.

  18. Purine and pyrimidine metabolism.

    Science.gov (United States)

    Zöllner, N

    1982-09-01

    The pathways of purine biosynthesis and degradation have been elucidated during the last 30 years; the regulation of the mechanisms involved is not yet fully understood, particularly with respect to quantitative aspects. Research into inborn errors of purine metabolism has provided valuable insights into purine synthesis and salvage pathways. Nutrition experiments using purine-free formula diets and supplements with defined purine sources permit precise descriptions of the influence of various dietary purines on uric acid formation. Supplements of dietary purines produce dose-proportional increases in plasma uric acid concentrations, uric acid pool size and renal uric acid excretion. The magnitude of these increases depends on the type of purine compound administered, which may limit the value of food tables for human dietetics. Purine content of food must be related not only to weight but also to energy and to protein, particularly if new foodstuffs or a vegetarian diet are ingested. Dietary purines appear to influence the biosynthesis of pyrimidines. In contrast to dietary purines, pyrimidines in the diet, if administered as nucleosides or nucleotides, are utilized in animals for the synthesis of nucleic acids. Much further work is necessary for a better understanding of the inter-relationships of purine and pyrimidine metabolism.

  19. Biochemical Hypermedia: Galactose Metabolism.

    Directory of Open Access Journals (Sweden)

    J.K. Sugai

    2013-05-01

    Full Text Available Introduction: Animations of biochemical processes and virtual laboratory environments lead to true molecular simulations. The use of interactive software’s in education can improve cognitive capacity, better learning and, mainly, it makes information acquisition easier. Material and Methods: This work presents the development of a biochemical hypermedia to understanding of the galactose metabolism. It was developed with the help of concept maps, ISIS Draw, ADOBE Photoshop and FLASH MX Program. Results and Discussion: A step by step animation process shows the enzymatic reactions of galactose conversion to glucose-1-phosphate (to glycogen synthesis, glucose-6-phosphate (glycolysis intermediary, UDP-galactose (substrate to mucopolysaccharides synthesis and collagen’s glycosylation. There are navigation guide that allow scrolling the mouse over the names of the components of enzymatic reactions of via the metabolism of galactose. Thus, explanatory text box, chemical structures and animation of the actions of enzymes appear to navigator. Upon completion of the module, the user’s response to the proposed exercise can be checked immediately through text box with interactive content of the answer. Conclusion: This hypermedia was presented for undergraduate students (UFSC who revealed that it was extremely effective in promoting the understanding of the theme.

  20. Posttransplant Metabolic Syndrome

    Directory of Open Access Journals (Sweden)

    M. Shadab Siddiqui

    2012-01-01

    Full Text Available Metabolic syndrome (MS is a cluster of metabolic derangements associated with insulin resistance and an increased risk of cardiovascular mortality. MS has become a major health concern worldwide and is considered to be the etiology of the current epidemic of diabetes and cardiovascular disease. In addition to cardiovascular disease, the presence of MS is also closely associated with other comorbidities including nonalcoholic fatty liver disease (NAFLD. The prevalence of MS in patients with cirrhosis and end-stage liver disease is not well established and difficult to ascertain. Following liver transplant, the prevalence of MS is estimated to be 44–58%. The main factors associated with posttransplant MS are posttransplant diabetes, obesity, dyslipidemia, and hypertension. In addition to developing NAFLD, posttransplant MS is associated with increased cardiovascular mortality that is 2.5 times that of the age- and sex-matched individuals. Additionally, the presence of posttransplant MS has been associated with rapid progression to fibrosis in individuals transplanted for HCV cirrhosis. There is an urgent need for well-designed prospective studies to fully delineate the natural history and risk factors associated with posttransplant MS. Until then, early recognition, prevention, and treatment of its components are vital in improving outcomes in liver transplant recipients.

  1. Arginine metabolism in wounds

    Energy Technology Data Exchange (ETDEWEB)

    Albina, J.E.; Mills, C.D.; Barbul, A.; Thirkill, C.E.; Henry, W.L. Jr.; Mastrofrancesco, B.; Caldwell, M.D.

    1988-04-01

    Arginine metabolism in wounds was investigated in the rat in 1) lambda-carrageenan-wounded skeletal muscle, 2) Schilling chambers, and 3) subcutaneous polyvinyl alcohol sponges. All showed decreased arginine and elevated ornithine contents and high arginase activity. Arginase could be brought to the wound by macrophages, which were found to contain arginase activity. However, arginase was expressed by macrophages only after cell lysis and no arginase was released by viable macrophages in vitro. Thus the extracellular arginase of wounds may derive from dead macrophages within the injured tissue. Wound and peritoneal macrophages exhibited arginase deiminase activity as demonstrated by the conversion of (guanido-/sup 14/C)arginine to radiolabeled citrulline during culture, the inhibition of this reaction by formamidinium acetate, and the lack of prokaryotic contamination of the cultures. These findings and the known metabolic fates of the products of arginase and arginine deiminase in the cellular populations of the wound suggest the possibility of cooperativity among cells for the production of substrates for collagen synthesis.

  2. Pharmacogenetics of olanzapine metabolism.

    Science.gov (United States)

    Söderberg, Mao Mao; Dahl, Marja-Liisa

    2013-08-01

    The pharmacokinetics of the atypical antipsychotic, olanzapine, display large interindividual variation leading to multiple-fold differences in drug exposure between patients at a given dose. This variation in turn gives rise to the need for individualized dosing in order to avoid concentration-dependent adverse effects or therapeutic failure. Genetically determined differences in olanzapine metabolism represent a less studied source of variability in comparison to environmental and physiological factors. In this review, we summarize available in vitro and in vivo data addressing the influence of polymorphisms in drug-metabolizing enzymes on olanzapine serum exposure. The polymorphic CYP2D6 enzyme appears to have no significant influence on olanzapine steady-state serum concentrations. The formation of the various olanzapine metabolites is influenced by polymorphisms in the genes coding for CYP1A2, CYP1A expression regulator AHR, UGT1A4 and UGT2B10, as well as FMO3. An impact on steady-state olanzapine serum concentrations has been suggested for variants of CYP1A2 and UGT1A4, with somewhat conflicting findings. The potential involvement of FMO1 and CYP3A43 in olanzapine disposition has also been suggested but needs future validation.

  3. Oxidative stress in metabolic syndrome

    OpenAIRE

    Sharma, Praveen; Mishra, Sandhya; Ajmera, Peeyush; Mathur, Sandeep

    2005-01-01

    As antioxidants play a protective role in the pathophysiology of diabetes and cardiovascular diseases, understanding the physiological status of antioxidant concentration among people at high risk for developing these conditions, such as Metabolic Syndrome, is of interest. In present study out of 187 first degree non-diabetic relatives and 192 non-diabetic spouses, 33.1% and 19.7% were found to have metabolic syndrome respectively. Subjects with metabolic syndrome (≥3 risk factors) had poor a...

  4. Brain glutamate metabolism during metabolic alkalosis and acidosis.

    Science.gov (United States)

    Ang, R C; Hoop, B; Kazemi, H

    1992-12-01

    Glutamate modifies ventilation by altering neural excitability centrally. Metabolic acid-base perturbations may also alter cerebral glutamate metabolism locally and thus affect ventilation. Therefore, the effect of metabolic acid-base perturbations on central nervous system glutamate metabolism was studied in pentobarbital-anesthetized dogs under normal acid-base conditions and during isocapnic metabolic alkalosis and acidosis. Cerebrospinal fluid transfer rates of radiotracer [13N]ammonia and of [13N]glutamine synthesized de novo via the reaction glutamate+NH3-->glutamine in brain glia were measured during normal acid-base conditions and after 90 min of acute isocapnic metabolic alkalosis and acidosis. Cerebrospinal fluid [13N]ammonia and [13N]glutamine transfer rates decreased in metabolic acidosis. Maximal glial glutamine efflux rate jm equals 85.6 +/- 9.5 (SE) mumol.l-1 x min-1 in all animals. No difference in jm was observed in metabolic alkalosis or acidosis. Mean cerebral cortical glutamate concentration was significantly lower in acidosis [7.01 +/- 0.45 (SE) mumol/g brain tissue] and tended to be larger in alkalosis, compared with 7.97 +/- 0.89 mumol/g in normal acid-base conditions. There was a similar change in cerebral cortical gamma-aminobutyric acid concentration. Within the limits of the present method and measurements, the results suggest that acute metabolic acidosis but not alkalosis reduces glial glutamine efflux, corresponding to changes in cerebral cortical glutamate metabolism. These results suggest that glutamatergic mechanisms may contribute to central respiratory control in metabolic acidosis.

  5. Molecular characterization of bacterial respiration on minerals. Progress report, June 1992--November, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Blake, R. II.

    1993-12-31

    Progress is reported towards elucidating electron transport components of Thiobacillus ferrooxidans involved in the metabolic oxidation of iron. Also included are results of an investigation into the molecular principles whereby the bacteria recognize and adhere to their insoluble substrates

  6. Drug-Induced Metabolic Acidosis.

    Science.gov (United States)

    Pham, Amy Quynh Trang; Xu, Li Hao Richie; Moe, Orson W

    2015-01-01

    Metabolic acidosis could emerge from diseases disrupting acid-base equilibrium or from drugs that induce similar derangements. Occurrences are usually accompanied by comorbid conditions of drug-induced metabolic acidosis, and clinical outcomes may range from mild to fatal. It is imperative that clinicians not only are fully aware of the list of drugs that may lead to metabolic acidosis but also understand the underlying pathogenic mechanisms. In this review, we categorized drug-induced metabolic acidosis in terms of pathophysiological mechanisms, as well as individual drugs' characteristics.

  7. Gut Microbiota and Metabolic Disorders

    Directory of Open Access Journals (Sweden)

    Kyu Yeon Hur

    2015-06-01

    Full Text Available Gut microbiota plays critical physiological roles in the energy extraction and in the control of local or systemic immunity. Gut microbiota and its disturbance also appear to be involved in the pathogenesis of diverse diseases including metabolic disorders, gastrointestinal diseases, cancer, etc. In the metabolic point of view, gut microbiota can modulate lipid accumulation, lipopolysaccharide content and the production of short-chain fatty acids that affect food intake, inflammatory tone, or insulin signaling. Several strategies have been developed to change gut microbiota such as prebiotics, probiotics, certain antidiabetic drugs or fecal microbiota transplantation, which have diverse effects on body metabolism and on the development of metabolic disorders.

  8. Drug-Induced Metabolic Acidosis

    Science.gov (United States)

    Pham, Amy Quynh Trang; Xu, Li Hao Richie; Moe, Orson W.

    2015-01-01

    Metabolic acidosis could emerge from diseases disrupting acid-base equilibrium or from drugs that induce similar derangements. Occurrences are usually accompanied by comorbid conditions of drug-induced metabolic acidosis, and clinical outcomes may range from mild to fatal. It is imperative that clinicians not only are fully aware of the list of drugs that may lead to metabolic acidosis but also understand the underlying pathogenic mechanisms. In this review, we categorized drug-induced metabolic acidosis in terms of pathophysiological mechanisms, as well as individual drugs’ characteristics. PMID:26918138

  9. Metabolic Adaptation to Muscle Ischemia

    Science.gov (United States)

    Cabrera, Marco E.; Coon, Jennifer E.; Kalhan, Satish C.; Radhakrishnan, Krishnan; Saidel, Gerald M.; Stanley, William C.

    2000-01-01

    Although all tissues in the body can adapt to varying physiological/pathological conditions, muscle is the most adaptable. To understand the significance of cellular events and their role in controlling metabolic adaptations in complex physiological systems, it is necessary to link cellular and system levels by means of mechanistic computational models. The main objective of this work is to improve understanding of the regulation of energy metabolism during skeletal/cardiac muscle ischemia by combining in vivo experiments and quantitative models of metabolism. Our main focus is to investigate factors affecting lactate metabolism (e.g., NADH/NAD) and the inter-regulation between carbohydrate and fatty acid metabolism during a reduction in regional blood flow. A mechanistic mathematical model of energy metabolism has been developed to link cellular metabolic processes and their control mechanisms to tissue (skeletal muscle) and organ (heart) physiological responses. We applied this model to simulate the relationship between tissue oxygenation, redox state, and lactate metabolism in skeletal muscle. The model was validated using human data from published occlusion studies. Currently, we are investigating the difference in the responses to sudden vs. gradual onset ischemia in swine by combining in vivo experimental studies with computational models of myocardial energy metabolism during normal and ischemic conditions.

  10. [Leaching of copper ore of the Udokanskoe deposit at low temperatures by an association of acidophilic chemolithotrophic microorganisms].

    Science.gov (United States)

    Kondrat'eva, T F; Pivovarova, T A; Krylova, L N; Melamud, V S; Adamov, E V; Karavaĭko, G I

    2011-01-01

    Pure cultures of indigenous microorganisms Acidithiobacillus ferrooxidans strain TFUd, Leptospirillum ferrooxidans strain LUd, and Sulfobacillus thermotolerans strain SUd have been isolated from the oxidation zone of sulfide copper ore of the Udokanskoe deposit. Regimes of bacterial-chemical leaching of ore have been studied over a temperature range from -10 to +20 degrees C. Effects of pH, temperature, and the presence of microorganisms on the extraction of copper have been shown. Bacterial leaching has been detected only at positive values of temperature, and has been much more active at +20 than at +4 degrees C. The process of leaching was more active when the ore contained more hydrophilic and oxidized minerals. The possibility of copper ore leaching of the Udokanskoe deposit using sulfuric acid with pH 0.4 at negative values of temperature and applying acidophilic chemolithotrophic microorganisms at positive values of temperature and low pH values was shown.

  11. Quantifying adhesion of acidophilic bioleaching bacteria to silica and pyrite by atomic force microscopy with a bacterial probe.

    Science.gov (United States)

    Diao, Mengxue; Taran, Elena; Mahler, Stephen; Nguyen, Tuan A H; Nguyen, Anh V

    2014-03-01

    The adhesion of acidophilic bacteria to mineral surfaces is an important phenomenon in bioleaching processes. In this study, functionalized colloidal probes covered by bioleaching bacterial cells (Acidithiobacillus thiooxidans and Leptospirillum ferrooxidans) were developed and used to sense specific adhesion forces to a silica surface and a pyrite surface in various solutions. Experimentally, recorded retraction curves of A. thiooxidans revealed sawtooth features that were in good agreement with the wormlike chain model, while that of L. ferrooxidans exhibited stair-step separation. The magnitudes of adhesion forces and snap-off distances were strongly influenced by the ionic strength and pH. Macroscopic surface properties including hydrophobicity and surface potential for bacterial cells and substrata were measured by a sessile drop method and microelectrophoresis. The ATR-FTIR spectra indicated the presence of different types of biopolymers on two strains of bacteria.

  12. 脱硫混合菌系构建及其脱除H2S的性能研究%Construction of Desulfurated Mixed Microbial Culture and Potential for H2S Removal

    Institute of Scientific and Technical Information of China (English)

    胡慧欣; 冯丹丹; 赵丹; 郝亚杰; 高超; 孙士男; 翟贺玲; 晏磊

    2014-01-01

    通过考察A cidithiobacillus ferrooxidans (A.ferrooxidans)和Acidithiobacillus thiooxidans (A.thiooxidans)的混合比例对Fe2+和S2O32-氧化及对H2S脱除的影响,来构建一组脱硫混合菌系.结果表明,当A.ferrooxidans和A.thiooxidans的最佳混合比例为1∶2时,Fe2+的氧化率达最大值99.6%,S2O32-氧化导致的pH降至最低1.03,而H2S的脱除率可达99.2%.因此,构建的脱硫混合菌系具有较好的应用潜力,可以用于H2S的脱除.

  13. Monitoring Acidophilic Microbes with Real-Time Polymerase Chain Reaction (PCR) Assays

    Energy Technology Data Exchange (ETDEWEB)

    Frank F. Roberto

    2008-08-01

    Many techniques that are used to characterize and monitor microbial populations associated with sulfide mineral bioleaching require the cultivation of the organisms on solid or liquid media. Chemolithotrophic species, such as Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans, or thermophilic chemolithotrophs, such as Acidianus brierleyi and Sulfolobus solfataricus can grow quite slowly, requiring weeks to complete efforts to identify and quantify these microbes associated with bioleach samples. Real-time PCR (polymerase chain reaction) assays in which DNA targets are amplified in the presence of fluorescent oligonucleotide primers, allowing the monitoring and quantification of the amplification reactions as they progress, provide a means of rapidly detecting the presence of microbial species of interest, and their relative abundance in a sample. This presentation will describe the design and use of such assays to monitor acidophilic microbes in the environment and in bioleaching operations. These assays provide results within 2-3 hours, and can detect less than 100 individual microbial cells.

  14. Cerebral metabolic adaptation and ketone metabolism after brain injury

    Science.gov (United States)

    Prins, Mayumi L

    2010-01-01

    The developing central nervous system has the capacity to metabolize ketone bodies. It was once accepted that on weaning, the ‘post-weaned/adult’ brain was limited solely to glucose metabolism. However, increasing evidence from conditions of inadequate glucose availability or increased energy demands has shown that the adult brain is not static in its fuel options. The objective of this review is to summarize the body of literature specifically regarding cerebral ketone metabolism at different ages, under conditions of starvation and after various pathologic conditions. The evidence presented supports the following findings: (1) there is an inverse relationship between age and the brain’s capacity for ketone metabolism that continues well after weaning; (2) neuroprotective potentials of ketone administration have been shown for neurodegenerative conditions, epilepsy, hypoxia/ischemia, and traumatic brain injury; and (3) there is an age-related therapeutic potential for ketone as an alternative substrate. The concept of cerebral metabolic adaptation under various physiologic and pathologic conditions is not new, but it has taken the contribution of numerous studies over many years to break the previously accepted dogma of cerebral metabolism. Our emerging understanding of cerebral metabolism is far more complex than could have been imagined. It is clear that in addition to glucose, other substrates must be considered along with fuel interactions, metabolic challenges, and cerebral maturation. PMID:17684514

  15. Metabolic interrelationships software application: Interactive learning tool for intermediary metabolism

    NARCIS (Netherlands)

    A.J.M. Verhoeven (Adrie); M. Doets (Mathijs); J.M.J. Lamers (Jos); J.F. Koster (Johan)

    2005-01-01

    textabstractWe developed and implemented the software application titled Metabolic Interrelationships as a self-learning and -teaching tool for intermediary metabolism. It is used by undergraduate medical students in an integrated organ systems-based and disease-oriented core curriculum, which start

  16. Metabolic interrelationships software application: Interactive learning tool for intermediary metabolism

    NARCIS (Netherlands)

    A.J.M. Verhoeven (Adrie); M. Doets (Mathijs); J.M.J. Lamers (Jos); J.F. Koster (Johan)

    2005-01-01

    textabstractWe developed and implemented the software application titled Metabolic Interrelationships as a self-learning and -teaching tool for intermediary metabolism. It is used by undergraduate medical students in an integrated organ systems-based and disease-oriented core curriculum, which

  17. Biodesulfurization of two Colombian coals with native microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    Cardona, Isabel Cristina; Marquez, Marco Antonio [Applied Mineralogy Group, National University of Colombia, Medellin, 05001000 (Colombia)

    2009-09-15

    A biodesulfurization process was carried out for two coals from the southwest of Colombia using a consortium of native microorganisms Acidithiobacillus ferrooxidans-like and Acidithiobacillus thiooxidans-like. Characterization techniques as X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM/EDX) and chemical analysis were used in order to establish the mineralogy of the process. The sulfur content in coals varies from 2.6% to 5.7%, and pyrite is the main sulphide present in the inorganic phase. Other minerals in the substrates include kaolinite, calcite, dolomite and quartz. An 85-95% reduction of pyritic sulfur and 31-51% of total sulfur in a period of 30 days were achieved, for a particle size of - 74 {mu}m, 10% w/v pulp density and 30 C. (author)

  18. The Effect of Specific Conditions on Cu, Ni, Zn and Al Recovery from PCBS Waste Using Acidophilic Bacterial Strains

    Directory of Open Access Journals (Sweden)

    Mrážiková A.

    2016-03-01

    Full Text Available The objective of this work was to evaluate the influence of static, stirring and shaking conditions on copper, zinc, nickel and aluminium dissolution from printed circuit boards (PCBs using the mixed acidophilic bacterial culture of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans. The results revealed that static conditions were the most effective in zinc and aluminium dissolution. Zinc was removed almost completely under static conditions, whereas maximum of nickel dissolution was reached under the stirring conditions. The highest copper recovery (36% was reached under stirring conditions. The shaking conditions appeared to be the least suitable. The relative importance of these systems for the bioleaching of copper and nickel decreased in the order: stirring, static conditions, shaking.

  19. Structural control of metabolic flux.

    Directory of Open Access Journals (Sweden)

    Max Sajitz-Hermstein

    Full Text Available Organisms have to continuously adapt to changing environmental conditions or undergo developmental transitions. To meet the accompanying change in metabolic demands, the molecular mechanisms of adaptation involve concerted interactions which ultimately induce a modification of the metabolic state, which is characterized by reaction fluxes and metabolite concentrations. These state transitions are the effect of simultaneously manipulating fluxes through several reactions. While metabolic control analysis has provided a powerful framework for elucidating the principles governing this orchestrated action to understand metabolic control, its applications are restricted by the limited availability of kinetic information. Here, we introduce structural metabolic control as a framework to examine individual reactions' potential to control metabolic functions, such as biomass production, based on structural modeling. The capability to carry out a metabolic function is determined using flux balance analysis (FBA. We examine structural metabolic control on the example of the central carbon metabolism of Escherichia coli by the recently introduced framework of functional centrality (FC. This framework is based on the Shapley value from cooperative game theory and FBA, and we demonstrate its superior ability to assign "share of control" to individual reactions with respect to metabolic functions and environmental conditions. A comparative analysis of various scenarios illustrates the usefulness of FC and its relations to other structural approaches pertaining to metabolic control. We propose a Monte Carlo algorithm to estimate FCs for large networks, based on the enumeration of elementary flux modes. We further give detailed biological interpretation of FCs for production of lactate and ATP under various respiratory conditions.

  20. Metabolism during hypodynamia

    Science.gov (United States)

    Federov, I. V.

    1980-01-01

    Physical immobilization, inaction due to space travel, a sedentary occupation, or bed confinement due to a chronic illness elicit similar alternations in the metabolism of man and animals (rat, rabbit, dog, mouse). After a preliminary period of weight loss, there is eventually weight gain due to increased lipid storage. Protein catabolism is enhanced and anabolism depressed, with elevated urinary excretion of amino acids, creatine, and ammonia. Glycogen stores are depleted and glyconeogenesis is accelerated. Polyuria develops with subsequent redistribution of body fluids in which the blood volume of the systemic circulation is decreased and that of pulmonary circulation increased. This results in depressed production of vasopressin by the posterior pituitary which further enhances urinary water and salt loss.

  1. The metabolic syndrome.

    Science.gov (United States)

    Harris, Mark F

    2013-08-01

    The metabolic syndrome (MetSy) is increasingly common in Australia. It is associated with the rise in obesity and lifestyle risk behaviours. It is also controversial - its value in predicting cardiovascular disease and diabetes risk and in guiding therapy has been challenged. This article aims to provide advice on the diagnosis of the MetSy and the principles for its prevention and management in the context of primary care, taking into consideration aetiological factors and the complexity of managing its constituent risk factors. Diagnosis of the MetSy is useful in focusing attention on central adiposity and insulin resistance as risk factors both for the syndrome, and cardiovascular and diabetes morbidity and mortality. Its assessment requires measurement of waist circumference - a simple but seldom performed procedure in general practice. The most essential components for the prevention and management of the MetSy are measures to change diet and physical activity in order to achieve and sustain weight loss.

  2. Regulation of Terpene Metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Rodney Croteau

    2004-03-14

    OAK-B135 Research over the last four years has progressed fairly closely along the lines initially proposed, with progress-driven expansion of Objectives 1, 2 and 3. Recent advances have developed from three research thrusts: 1. Random sequencing of an enriched peppermint oil gland cDNA library has given access to a large number of potential pathway and regulatory genes for test of function; 2. The availability of new DNA probes and antibodies has permitted investigation of developmental regulation and organization of terpenoid metabolism; and 3. The development of a transformation system for peppermint by colleagues at Purdue University has allowed direct transgenic testing of gene function and added a biotechnological component to the project. The current status of each of the original research objectives is outlined below.

  3. [Regulation of terpene metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Croteau, R.

    1989-11-09

    Terpenoid oils, resins, and waxes from plants are important renewable resources. The objective of this project is to understand the regulation of terpenoid metabolism using the monoterpenes (C[sub 10]) as a model. The pathways of monoterpene biosynthesis and catabolism have been established, and the relevant enzymes characterized. Developmental studies relating enzyme levels to terpene accumulation within the oil gland sites of synthesis, and work with bioregulators, indicate that monoterpene production is controlled by terpene cyclases, the enzymes catalyzing the first step of the monoterpene pathway. As the leaf oil glands mature, cyclase levels decline and monoterpene biosynthesis ceases. Yield then decreases as the monoterpenes undergo catabolism by a process involving conversion to a glycoside and transport from the leaf glands to the root. At this site, the terpenoid is oxidatively degraded to acetate that is recycled into other lipid metabolites. During the transition from terpene biosynthesis to catabolism, the oil glands undergo dramatic ultrastructural modification. Degradation of the producing cells results in mixing of previously compartmentized monoterpenes with the catabolic enzymes, ultimately leading to yield decline. This regulatory model is being applied to the formation of other terpenoid classes (C[sub 15] C[sub 20], C[sub 30], C[sub 40]) within the oil glands. Preliminary investigations on the formation of sesquiterpenes (C[sub 15]) suggest that the corresponding cyclases may play a lesser role in determining yield of these products, but that compartmentation effects are important. From these studies, a comprehensive scheme for the regulation of terpene metabolism is being constructed. Results from this project wail have important consequences for the yield and composition of terpenoid natural products that can be made available for industrial exploitation.

  4. Renal metabolism of calcitonin

    Energy Technology Data Exchange (ETDEWEB)

    Simmons, R.E.; Hjelle, J.T.; Mahoney, C.; Deftos, L.J.; Lisker, W.; Kato, P.; Rabkin, R.

    1988-04-01

    The kidneys account for approximately two-thirds of the metabolism of calcitonin, but relatively little is known regarding the details thereof. To further characterize this process, we examined the renal handling and metabolism of human calcitonin (hCT) by the isolated perfused rat kidney. We also studied the degradation of radiolabeled salmon calcitonin (sCT) by subcellular fractions prepared from isolated rabbit proximal tubules. The total renal (organ) clearance of immunoreactive hCT by the isolated kidney was 1.96 +/- 0.18 ml/min. This was independent of the perfusate total calcium concentration from 5.5 to 10.2 mg/dl. Total renal clearance exceeded the glomerular filtration rate (GFR, 0.68 +/- 0.05 ml/min), indicating filtration-independent removal. Urinary calcitonin clearance as a fraction of GFR averaged 2.6%. Gel filtration chromatography of medium from isolated kidneys perfused with /sup 125/I-labeled sCT showed the principal degradation products to be low molecular weight forms eluting with monoiodotyrosine. Intermediate size products were not detected. In the subcellular fractionation experiments, when carried out at pH 5.0, calcitonin hydrolysis exclusively followed the activities of the lysosomal enzyme N-acetyl-beta-glucosaminidase. Typically, at pH 7.5, 42% of total degradation occurred in the region of the brush-border enzyme alanyl aminopeptidase and 29% occurred in the region of the cytosolic enzyme phosphoglucomutase. Although 9% of the calcitonin-degrading activity was associated with basolateral membrane fractions, most of this activity could be accounted for by the presence of brush-border membranes.

  5. Bioproduction of ferric sulfate used during heavy metals removal from sewage sludge.

    Science.gov (United States)

    Drogui, Patrick; Mercier, Guy; Blais, Jean-François

    2005-01-01

    Toxic metals removal from wastewater sewage sludge can be achieved through microbial processes involving Acidithiobacillus ferrooxidans. The oxidation of ferrous ions by A. ferrooxidans, cultured in sewage sludge filtrate, was studied in both batch and continuous flow stirred tank reactors. Sewage sludge filtrate containing natural nutrients (phosphorus and nitrogen) was recovered as effluent following the dehydration of a primary and secondary sludge mixture. Batch and continuous flow stirred tank reactor tests demonstrated that A. ferrooxidans were able to grow and completely oxidize ferrous iron in a culture medium containing more than 80% (v v(-1)) sewage sludge filtrate with 10 g Fe(II) L(-1) added. Toxic levels were reached when total organic carbon in the sewage sludge filtrate exceeded 250 mg L(-1). The ferric iron solution produced in the sludge filtrate by A. ferrooxidans was used to solubilize heavy metals in primary and secondary sludge. The solubilization of Cu, Cr, and Zn yielded 71, 49, and 80%, respectively. This is comparable with the yield percentages obtained using a FeCl(3) solution. The cost of treating wastewater sewage sludge by bioproducing a ferric ion solution from sewage sludge is three times less expensive than the conventional method requiring a commercial ferric chloride solution.

  6. Extracellular polymeric bacterial coverages as minimal surfaces

    CERN Document Server

    Saa, A; Saa, Alberto; Teschke, Omar

    2005-01-01

    Surfaces formed by extracellular polymeric substances enclosing individual and some small communities of {\\it Acidithiobacillus ferrooxidans} on plates of hydrophobic silicon and hydrophilic mica are analyzed by means of atomic force microscopy imaging. Accurate nanoscale descriptions of such coverage surfaces are obtained. The good agreement with the predictions of a rather simple but realistic theoretical model allows us to conclude that they correspond, indeed, to minimal area surfaces enclosing a given volume associated with the encased bacteria. This is, to the best of our knowledge, the first shape characterization of the coverage formed by these biomolecules, with possible applications to the study of biofilms.

  7. Cancer Metabolism and Drug Resistance

    Directory of Open Access Journals (Sweden)

    Mahbuba Rahman

    2015-09-01

    Full Text Available Metabolic alterations, driven by genetic and epigenetic factors, have long been known to be associated with the etiology of cancer. Furthermore, accumulating evidence suggest that cancer metabolism is intimately linked to drug resistance, which is currently one of the most important challenges in cancer treatment. Altered metabolic pathways help cancer cells to proliferate at a rate higher than normal, adapt to nutrient limited conditions, and develop drug resistance phenotypes. Application of systems biology, boosted by recent advancement of novel high-throughput technologies to obtain cancer-associated, transcriptomic, proteomic and metabolomic data, is expected to make a significant contribution to our understanding of metabolic properties related to malignancy. Indeed, despite being at a very early stage, quantitative data obtained from the omics platforms and through applications of 13C metabolic flux analysis (MFA in in vitro studies, researchers have already began to gain insight into the complex metabolic mechanisms of cancer, paving the way for selection of molecular targets for therapeutic interventions. In this review, we discuss some of the major findings associated with the metabolic pathways in cancer cells and also discuss new evidences and achievements on specific metabolic enzyme targets and target-directed small molecules that can potentially be used as anti-cancer drugs.

  8. Selected Metabolic Responses to Skateboarding

    Science.gov (United States)

    Hetzler, Ronald K.; Hunt, Ian; Stickley, Christopher D.; Kimura, Iris F.

    2011-01-01

    Despite the popularity of skateboarding worldwide, the authors believe that no previous studies have investigated the metabolic demands associated with recreational participation in the sport. Although metabolic equivalents (METs) for skateboarding were published in textbooks, the source of these values is unclear. Therefore, the rise in…

  9. Multidimensional optimality of microbial metabolism

    NARCIS (Netherlands)

    Schuetz, Robert; Zamboni, Nicola; Zampieri, Mattia; Heinemann, Matthias; Sauer, Uwe

    2012-01-01

    Although the network topology of metabolism is well known, understanding the principles that govern the distribution of fluxes through metabolism lags behind. Experimentally, these fluxes can be measured by (13)C-flux analysis, and there has been a long-standing interest in understanding this functi

  10. Metabolic alterations in dialysis patients

    NARCIS (Netherlands)

    Drechsler, Christiane

    2010-01-01

    Assessing metabolic risk in dialysis patients, three main aspects are important: a) the pathophysiologic effects of metabolic disturbances as known from the general population are unlikely to completely reverse once patients reach dialysis. b) Specific additional problems related to chronic kidney d

  11. Sex steroids and lipoprotein metabolism

    NARCIS (Netherlands)

    Gevers Leuven, J.A.

    1994-01-01

    Lipoprotein metabolism is involved in atherogenesis. Female sex-hormones have substantial effects on both lipoprotein metabolism and the vessel wall. Cholesterol, one of the major lipids in lipoproteins, is both the substrate for, and the target of, the steroidal sex hormones.

  12. Estrogen Signaling in Metabolic Inflammation

    Directory of Open Access Journals (Sweden)

    Rosário Monteiro

    2014-01-01

    Full Text Available There is extensive evidence supporting the interference of inflammatory activation with metabolism. Obesity, mainly visceral obesity, is associated with a low-grade inflammatory state, triggered by metabolic surplus where specialized metabolic cells such as adipocytes activate cellular stress initiating and sustaining the inflammatory program. The increasing prevalence of obesity, resulting in increased cardiometabolic risk and precipitating illness such as cardiovascular disease, type 2 diabetes, fatty liver, cirrhosis, and certain types of cancer, constitutes a good example of this association. The metabolic actions of estrogens have been studied extensively and there is also accumulating evidence that estrogens influence immune processes. However, the connection between these two fields of estrogen actions has been underacknowledged since little attention has been drawn towards the possible action of estrogens on the modulation of metabolism through their anti-inflammatory properties. In the present paper, we summarize knowledge on the modification inflammatory processes by estrogens with impact on metabolism and highlight major research questions on the field. Understanding the regulation of metabolic inflammation by estrogens may provide the basis for the development of therapeutic strategies to the management of metabolic dysfunctions.

  13. Metabolic syndrome and oxidative stress.

    Science.gov (United States)

    Ando, Katsuyuki; Fujita, Toshiro

    2009-08-01

    Metabolic syndrome is an obesity-associated collection of disorders, each of which contributes to cardiovascular risk. Metabolic syndrome is also associated with overproduction of reactive oxygen species (ROS). ROS contribute to the interrelationship between metabolic syndrome and salt-sensitive hypertension, which are both caused by obesity and excess salt consumption and are major threats to health in developed countries. ROS can induce insulin resistance, which is indispensable for the progression of metabolic syndrome, and salt-sensitive hypertension stimulates ROS production, thereby promoting the development of metabolic syndrome. Moreover, ROS activate mineralocorticoid receptors (MRs) and the sympathetic nervous system, which can contribute to the development of metabolic syndrome and salt-sensitive hypertension. Salt-induced progression of cardiovascular disease (CVD) is also accelerated in animal models with metabolic syndrome, probably owing to further stimulation of ROS overproduction and subsequent ROS-induced MR activation and sympathetic excitation. Therefore, ROS contribute to the progression of the metabolic syndrome itself and to the CVD accompanying it, particularly in conjunction with excessive salt consumption.

  14. Metabolic alterations in dialysis patients

    NARCIS (Netherlands)

    Drechsler, Christiane

    2010-01-01

    Assessing metabolic risk in dialysis patients, three main aspects are important: a) the pathophysiologic effects of metabolic disturbances as known from the general population are unlikely to completely reverse once patients reach dialysis. b) Specific additional problems related to chronic kidney

  15. Lysophosphatidylinositol Signalling and Metabolic Diseases

    Directory of Open Access Journals (Sweden)

    Syamsul A. Arifin

    2016-01-01

    Full Text Available Metabolism is a chemical process used by cells to transform food-derived nutrients, such as proteins, carbohydrates and fats, into chemical and thermal energy. Whenever an alteration of this process occurs, the chemical balance within the cells is impaired and this can affect their growth and response to the environment, leading to the development of a metabolic disease. Metabolic syndrome, a cluster of several metabolic risk factors such as abdominal obesity, insulin resistance, high cholesterol and high blood pressure, and atherogenic dyslipidaemia, is increasingly common in modern society. Metabolic syndrome, as well as other diseases, such as diabetes, obesity, hyperlipidaemia and hypertension, are associated with abnormal lipid metabolism. Cellular lipids are the major component of cell membranes; they represent also a valuable source of energy and therefore play a crucial role for both cellular and physiological energy homeostasis. In this review, we will focus on the physiological and pathophysiological roles of the lysophospholipid mediator lysophosphatidylinositol (LPI and its receptor G-protein coupled receptor 55 (GPR55 in metabolic diseases. LPI is a bioactive lipid generated by phospholipase A (PLA family of lipases which is believed to play an important role in several diseases. Indeed LPI can affect various functions such as cell growth, differentiation and motility in a number of cell-types. Recently published data suggest that LPI plays an important role in different physiological and pathological contexts, including a role in metabolism and glucose homeostasis.

  16. Cancer Metabolism and Drug Resistance

    Science.gov (United States)

    Rahman, Mahbuba; Hasan, Mohammad Rubayet

    2015-01-01

    Metabolic alterations, driven by genetic and epigenetic factors, have long been known to be associated with the etiology of cancer. Furthermore, accumulating evidence suggest that cancer metabolism is intimately linked to drug resistance, which is currently one of the most important challenges in cancer treatment. Altered metabolic pathways help cancer cells to proliferate at a rate higher than normal, adapt to nutrient limited conditions, and develop drug resistance phenotypes. Application of systems biology, boosted by recent advancement of novel high-throughput technologies to obtain cancer-associated, transcriptomic, proteomic and metabolomic data, is expected to make a significant contribution to our understanding of metabolic properties related to malignancy. Indeed, despite being at a very early stage, quantitative data obtained from the omics platforms and through applications of 13C metabolic flux analysis (MFA) in in vitro studies, researchers have already began to gain insight into the complex metabolic mechanisms of cancer, paving the way for selection of molecular targets for therapeutic interventions. In this review, we discuss some of the major findings associated with the metabolic pathways in cancer cells and also discuss new evidences and achievements on specific metabolic enzyme targets and target-directed small molecules that can potentially be used as anti-cancer drugs. PMID:26437434

  17. Gait Dynamics and Locomotor Metabolism

    Science.gov (United States)

    2014-12-01

    26 47. Taylor CR, Heglund NC, Maloiy GMO . Energetics and mechanics of terrestrial locomotion. I. Metabolic energy consumption as a function of...San Diego, CA: Academic Press, 1994. 110 47. Taylor CR, Heglund NC, Maloiy GMO . Energetics and mechanics of terrestrial locomotion. I. Metabolic

  18. [Hypovitaminosis D and metabolic syndrome].

    Science.gov (United States)

    Miñambres, Inka; de Leiva, Alberto; Pérez, Antonio

    2014-12-23

    Metabolic syndrome and hypovitaminosis D are 2 diseases with high prevalence that share several risk factors, while epidemiological evidence shows they are associated. Although the mechanisms involved in this association are not well established, hypovitaminosis D is associated with insulin resistance, decreased insulin secretion and activation of the renin-angiotensin system, mechanisms involved in the pathophysiology of metabolic syndrome. However, the apparent ineffectiveness of vitamin D supplementation on metabolic syndrome components, as well as the limited information about the effect of improving metabolic syndrome components on vitamin D concentrations, does not clarify the direction and the mechanisms involved in the causal relationship between these 2 pathologies. Overall, because of the high prevalence and the epidemiological association between both diseases, hypovitaminosis D could be considered a component of the metabolic syndrome.

  19. Retinoid Metabolism and Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    Eun-Jung Rhee

    2012-06-01

    Full Text Available Retinoid acid is a metabolite of vitamin A and functions as an important factor in cell survival, differentiation and death. Most previous studies on retinoid metabolism have focused on its association with cancer, hematologic and dermatologic disorders. Given the special concern over the recent increase in the prevalence of diabetes worldwide, the role of retinoid metabolism on glucose metabolism and insulin resistance in the human body is of marked importance. Therefore, in this issue, we review the literature on the association of retinoid metabolism with glucose tolerance, with regard to insulin secretion, pancreatic autoimmunity, insulin sensitivity and lipid metabolism. Further, we tried to assess the possibility of using retinoids as a novel therapeutic strategy for diabetes.

  20. Metabolic regulation of circadian clocks.

    Science.gov (United States)

    Haydon, Michael J; Hearn, Timothy J; Bell, Laura J; Hannah, Matthew A; Webb, Alex A R

    2013-05-01

    Circadian clocks are 24-h timekeeping mechanisms, which have evolved in plants, animals, fungi and bacteria to anticipate changes in light and temperature associated with the rotation of the Earth. The current paradigm to explain how biological clocks provide timing information is based on multiple interlocking transcription-translation negative feedback loops (TTFL), which drive rhythmic gene expression and circadian behaviour of growth and physiology. Metabolism is an important circadian output, which in plants includes photosynthesis, starch metabolism, nutrient assimilation and redox homeostasis. There is increasing evidence in a range of organisms that these metabolic outputs can also contribute to circadian timing and might also comprise independent circadian oscillators. In this review, we summarise the mechanisms of circadian regulation of metabolism by TTFL and consider increasing evidence that rhythmic metabolism contributes to the circadian network. We highlight how this might be relevant to plant circadian clock function.

  1. [Hypertension and the metabolic syndrome.

    DEFF Research Database (Denmark)

    Olsen, Michael; Jeppesen, Jørgen; Larsen, Mogens

    2009-01-01

    risk associated with increased blood pressure. As the definition of the metabolic syndrome is based on dichotomization of cardiovascular risk factors with a continuously increasing risk, it cannot match risk stratification tools like the HeartScore for calculation of prognosis. However, the metabolic......The metabolic syndrome is a relatively prevalent condition characterized by co-existence of several metabolic and cardiovascular risk factors including hypertension. Patients with hypertension have an increased risk of developing the metabolic syndrome which, in turn, increases the cardiovascular...... syndrome is of clinical importance as it makes the treating physician test for other elements of the syndrome in patients with one of the elements, e.g. hypertension. Udgivelsesdato: 2009-Jun-15...

  2. CIDE proteins and lipid metabolism.

    Science.gov (United States)

    Xu, Li; Zhou, Linkang; Li, Peng

    2012-05-01

    Lipid homeostasis is maintained through the coordination of lipid metabolism in various tissues, including adipose tissue and the liver. The disruption of lipid homeostasis often results in the development of metabolic disorders such as obesity, diabetes mellitus, liver steatosis, and cardiovascular diseases. Cell death-inducing DNA fragmentation factor 45-like effector family proteins, including Cidea, Cideb, and Fsp27 (Cidec), are emerging as important regulators of various lipid metabolic pathways and play pivotal roles in the development of metabolic disorders. This review summarizes the latest cell death-inducing DNA fragmentation factor 45-like effector protein discoveries related to the control of lipid metabolism, with emphasis on the role of these proteins in lipid droplet growth in adipocytes and in the regulation of very low-density lipoprotein lipidation and maturation in hepatocytes.

  3. Vasomotor symptoms and metabolic syndrome.

    Science.gov (United States)

    Tuomikoski, Pauliina; Savolainen-Peltonen, Hanna

    2017-03-01

    A vast majority of menopausal women suffer from vasomotor symptoms, such as hot flushes and night sweats, the mean duration of which may be up to 7-10 years. In addition to a decreased quality of life, vasomotor symptoms may have an impact on overall health. Vasomotor symptoms are associated with overactivity of the sympathetic nervous system, and sympathetic overdrive in turn is associated with metabolic syndrome, which is a known risk factor for cardiovascular disease. Menopausal hot flushes have a complex relationship to different features of the metabolic syndrome and not all data point towards an association between vasomotor symptoms and metabolic syndrome. Thus, it is still unclear whether vasomotor symptoms are an independent risk factor for metabolic syndrome. Research in this area is constantly evolving and we present here the most recent data on the possible association between menopausal vasomotor symptoms and the metabolic syndrome.

  4. [EEG manifestations in metabolic encephalopathy].

    Science.gov (United States)

    Lin, Chou-Ching K

    2005-09-01

    Normal brain function depends on normal neuronal metabolism, which is closely related to systemic homeostasis of metabolites, such as glucose, electrolytes, amino acids and ammonia. "Metabolic encephalopathy" indicates diffuse brain dysfunction caused by various systemic derangements. Electroencephalogram (EEG) is widely used to evaluate metabolic encephalopathy since 1937, when Berger first observed slow brain activity induced by hypoglycemia. EEG is most useful in differentiating organic from psychiatric conditions, identifying epileptogenicity, and providing information about the degree of cortical or subcortical dysfunction. In metabolic encephalopathy, EEG evolution generally correlates well with the severity of encephalopathy. However, EEG has little specificity in differentiating etiologies in metabolic encephalopathy. For example, though triphasic waves are most frequently mentioned in hepatic encephalopathy, they can also be seen in uremic encephalopathy, or even in aged psychiatric patients treated with lithium. Spike-and-waves may appear in hyper- or hypo-glycemia, uremic encephalopathy, or vitamin deficiencies, etc. Common principles of EEG changes in metabolic encephalopathy are (1) varied degrees of slowing, (2) assorted mixtures of epileptic discharge, (3) high incidence of triphasic waves, and (4), as a rule, reversibility after treatment of underlying causes. There are some exceptions to the above descriptions in specific metabolic disorders and EEG manifestations are highly individualized.

  5. Martial Arts and Metabolic Diseases

    Directory of Open Access Journals (Sweden)

    Hidetaka Hamasaki

    2016-05-01

    Full Text Available Different forms of martial arts are practiced worldwide, each with various intensities of physical activity. These disciplines are potentially an effective exercise therapy for metabolic diseases. Tai chi is the most well-studied style of martial arts and has shown evidence of its effect on metabolic diseases; however, little evidence is available regarding the association between other styles of martial arts and metabolic health. To summarize and evaluate the effects of martial arts on metabolic diseases, eligible articles were searched by using Pubmed. To date, systematic reviews provide no definite conclusion on the effectiveness of tai chi for treating metabolic diseases because of a small numbers of subjects, short durations of clinical trials, and some biases involved in testing. However, there are several clinical studies on subjects with metabolic diseases, which show that tai chi improves obesity, glycemic control, blood pressure control, and lipid profiles. Currently, some limited evidence suggests that other martial arts, such as kung fu and karate, may be beneficial for body composition, glycemic control, and arterial stiffness. To clarify the effectiveness of martial arts for treating metabolic diseases, well-designed prospective studies, preferably with a larger number of subjects and of longer duration, are warranted.

  6. Metabolic syndrome and eye diseases.

    Science.gov (United States)

    Poh, Stanley; Mohamed Abdul, Riswana Banu Binte; Lamoureux, Ecosse L; Wong, Tien Y; Sabanayagam, Charumathi

    2016-03-01

    Metabolic syndrome is becoming a worldwide medical and public health challenge as it has been seen increasing in prevalence over the years. Age-related eye diseases, the leading cause of blindness globally and visual impairment in developed countries, are also on the rise due to aging of the population. Many of the individual components of the metabolic syndrome have been shown to be associated with these eye diseases. However, the association of metabolic syndrome with eye diseases is not clear. In this review, we reviewed the evidence for associations between metabolic syndrome and certain ocular diseases in populations. We also reviewed the association of individual metabolic syndrome components with ocular diseases due to a paucity of research in this area. Besides, we also summarised the current understanding of etiological mechanisms of how metabolic syndrome or the individual components lead to these ocular diseases. With increasing evidence of such associations, it may be important to identify patients who are at risk of developing metabolic syndrome as prompt treatment and intervention may potentially decrease the risk of developing certain ocular diseases.

  7. Lactate metabolism in acute uremia.

    Science.gov (United States)

    Leverve, Xavier; Mustafa, Iqbal; Novak, Ivan; Krouzecky, Ales; Rokyta, Richard; Matejovic, Martin; Ichai, Carole

    2005-01-01

    Lactate is a key metabolite that is produced by every cell and oxidized by most of them, provided that they do contain mitochondria. Its metabolism is connected to energetic homeostasis and the cellular redox state. It is well recognized as an indicator of severe outcome in severely ill patients, however, it is not a detrimental factor per se. Conversely, some recent data tend even to indicate a beneficial effect in several metabolic disorders. Although the liver has long been recognized as a key organ in lactate homeostasis, the kidney also plays a major role as a gluconeogenic organ significantly involved in the glucose-lactate cycle. In acute renal failure, sodium lactate is widely used as a buffer in replacement fluids because the anion (lactate - ) is metabolized and the cation (Na + ) remains, leading to decreased water dissociation and proton concentration. The metabolic disorders related to acute renal failure or associated with it, such as liver failure, may affect lactate metabolism, and therefore they are often regarded as limiting factors for the use of lactate-containing fluids in such patients. By investigating endogenous lactate production in severe septic patients with acute renal failure, we found that an acute exogenous load of lactate did not affect the basal endogenous lactate production and metabolism. This indicates that exogenous lactate is well metabolized even in patients suffering from acute renal failure and severe sepsis with a compromised hemodynamic status.

  8. Xenobiotic Metabolism and Gut Microbiomes

    Science.gov (United States)

    Das, Anubhav; Srinivasan, Meenakshi; Ghosh, Tarini Shankar; Mande, Sharmila S.

    2016-01-01

    Humans are exposed to numerous xenobiotics, a majority of which are in the form of pharmaceuticals. Apart from human enzymes, recent studies have indicated the role of the gut bacterial community (microbiome) in metabolizing xenobiotics. However, little is known about the contribution of the plethora of gut microbiome in xenobiotic metabolism. The present study reports the results of analyses on xenobiotic metabolizing enzymes in various human gut microbiomes. A total of 397 available gut metagenomes from individuals of varying age groups from 8 nationalities were analyzed. Based on the diversities and abundances of the xenobiotic metabolizing enzymes, various bacterial taxa were classified into three groups, namely, least versatile, intermediately versatile and highly versatile xenobiotic metabolizers. Most interestingly, specific relationships were observed between the overall drug consumption profile and the abundance and diversity of the xenobiotic metabolizing repertoire in various geographies. The obtained differential abundance patterns of xenobiotic metabolizing enzymes and bacterial genera harboring them, suggest their links to pharmacokinetic variations among individuals. Additional analyses of a few well studied classes of drug modifying enzymes (DMEs) also indicate geographic as well as age specific trends. PMID:27695034

  9. MicroRNAs in Metabolism

    DEFF Research Database (Denmark)

    Vienberg, Sara; Geiger, Julian; Madsen, Søren

    2017-01-01

    MicroRNAs (miRNAs) have within the past decade emerged as key regulators of metabolic homeostasis. Major tissues in intermediary metabolism important during development of the metabolic syndrome, such as β-cells, liver, skeletal and heart muscle as well as adipose tissue have all been shown to be...... diabetes and atherosclerosis stresses their potential as therapeutic targets. This review emphasizes current ideas and controversies within miRNA research in metabolism. This article is protected by copyright. All rights reserved.......MicroRNAs (miRNAs) have within the past decade emerged as key regulators of metabolic homeostasis. Major tissues in intermediary metabolism important during development of the metabolic syndrome, such as β-cells, liver, skeletal and heart muscle as well as adipose tissue have all been shown...... to be affected by miRNAs. In the pancreatic β-cell a number of miRNAs are important in maintaining the balance between differentiation and proliferation (miR-200 and miR-29 families) and insulin exocytosis in the differentiated state is controlled by miR-7, miR-375 and miR-335. MiR-33a and -33b play crucial...

  10. [Regulation of terpene metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Croteau, R.

    1991-01-01

    During the last grant period, we have completed studies on the key pathways of monoterpene biosynthesis and catabolism in sage and peppermint, and have, by several lines of evidence, deciphered the rate-limiting step of each pathway. We have at least partially purified and characterized the relevant enzymes of each pathway. We have made a strong case, based on analytical, in vivo, and in vitro studies, that terpene accumulation depends upon the balance between biosynthesis and catabolism, and provided supporting evidence that these processes are developmentally-regulated and very closely associated with senescence of the oil glands. Oil gland ontogeny has been characterized at the ultrastructural level. We have exploited foliar-applied bioregulators to delay gland senescence, and have developed tissue explant and cell culture systems to study several elusive aspects of catabolism. We have isolated pure gland cell clusters and localized monoterpene biosynthesis and catabolism within these structures, and have used these preparations as starting materials for the purification to homogeneity of target regulatory'' enzymes. We have thus developed the necessary background knowledge, based on a firm understanding of enzymology, as well as the necessary experimental tools for studying the regulation of monoterpene metabolism at the molecular level. Furthermore, we are now in a position to extend our systematic approach to other terpenoid classes (C[sub 15]-C[sub 30]) produced by oil glands.

  11. Physics of metabolic organization.

    Science.gov (United States)

    Jusup, Marko; Sousa, Tânia; Domingos, Tiago; Labinac, Velimir; Marn, Nina; Wang, Zhen; Klanjšček, Tin

    2016-09-09

    We review the most comprehensive metabolic theory of life existing to date. A special focus is given to the thermodynamic roots of this theory and to implications that the laws of physics-such as the conservation of mass and energy-have on all life. Both the theoretical foundations and biological applications are covered. Hitherto, the foundations were more accessible to physicists or mathematicians, and the applications to biologists, causing a dichotomy in what always should have been a single body of work. To bridge the gap between the two aspects of the same theory, we (i) adhere to the theoretical formalism, (ii) try to minimize the amount of information that a reader needs to process, but also (iii) invoke examples from biology to motivate the introduction of new concepts and to justify the assumptions made, and (iv) show how the careful formalism of the general theory enables modular, self-consistent extensions that capture important features of the species and the problem in question. Perhaps the most difficult among the introduced concepts, the utilization (or mobilization) energy flow, is given particular attention in the form of an original and considerably simplified derivation. Specific examples illustrate a range of possible applications-from energy budgets of individual organisms, to population dynamics, to ecotoxicology.

  12. Physics of metabolic organization

    Science.gov (United States)

    Jusup, Marko; Sousa, Tânia; Domingos, Tiago; Labinac, Velimir; Marn, Nina; Wang, Zhen; Klanjšček, Tin

    2017-03-01

    We review the most comprehensive metabolic theory of life existing to date. A special focus is given to the thermodynamic roots of this theory and to implications that the laws of physics-such as the conservation of mass and energy-have on all life. Both the theoretical foundations and biological applications are covered. Hitherto, the foundations were more accessible to physicists or mathematicians, and the applications to biologists, causing a dichotomy in what always should have been a single body of work. To bridge the gap between the two aspects of the same theory, we (i) adhere to the theoretical formalism, (ii) try to minimize the amount of information that a reader needs to process, but also (iii) invoke examples from biology to motivate the introduction of new concepts and to justify the assumptions made, and (iv) show how the careful formalism of the general theory enables modular, self-consistent extensions that capture important features of the species and the problem in question. Perhaps the most difficult among the introduced concepts, the utilization (or mobilization) energy flow, is given particular attention in the form of an original and considerably simplified derivation. Specific examples illustrate a range of possible applications-from energy budgets of individual organisms, to population dynamics, to ecotoxicology.

  13. Regulation of sphingomyelin metabolism.

    Science.gov (United States)

    Bienias, Kamil; Fiedorowicz, Anna; Sadowska, Anna; Prokopiuk, Sławomir; Car, Halina

    2016-06-01

    Sphingolipids (SFs) represent a large class of lipids playing diverse functions in a vast number of physiological and pathological processes. Sphingomyelin (SM) is the most abundant SF in the cell, with ubiquitous distribution within mammalian tissues, and particularly high levels in the Central Nervous System (CNS). SM is an essential element of plasma membrane (PM) and its levels are crucial for the cell function. SM content in a cell is strictly regulated by the enzymes of SM metabolic pathways, which activities create a balance between SM synthesis and degradation. The de novo synthesis via SM synthases (SMSs) in the last step of the multi-stage process is the most important pathway of SM formation in a cell. The SM hydrolysis by sphingomyelinases (SMases) increases the concentration of ceramide (Cer), a bioactive molecule, which is involved in cellular proliferation, growth and apoptosis. By controlling the levels of SM and Cer, SMSs and SMases maintain cellular homeostasis. Enzymes of SM cycle exhibit unique properties and diverse tissue distribution. Disturbances in their activities were observed in many CNS pathologies. This review characterizes the physiological roles of SM and enzymes controlling SM levels as well as their involvement in selected pathologies of the Central Nervous System, such as ischemia/hypoxia, Alzheimer disease (AD), Parkinson disease (PD), depression, schizophrenia and Niemann Pick disease (NPD). Copyright © 2016 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

  14. MicroRNAs in Metabolism and Metabolic Disorders

    Science.gov (United States)

    Rottiers, Veerle; Näär, Anders M.

    2014-01-01

    MicroRNAs (miRNAs) have recently emerged as key regulators of metabolism. For example, miR-33a and b play a crucial role in controlling cholesterol and lipid metabolism in concert with their host genes, the SREBP transcription factors. Metabolic miRNAs such as miR-103 and miR-107 regulate insulin and glucose homeostasis, while others, such as miR-34a, may be key regulators of hepatic lipid homeostasis. The discovery of circulating miRNAs has highlighted their potential as both endocrine signalling molecules and disease markers. Dysregulation of miRNAs may contribute to metabolic abnormalities, suggesting that miRNAs may potentially serve as therapeutic targets to ameliorate cardiometabolic disorders. PMID:22436747

  15. Brain Regulation of Energy Metabolism.

    Science.gov (United States)

    Roh, Eun; Kim, Min Seon

    2016-12-01

    In healthy individuals, energy intake is in balance with energy expenditure, which helps to maintain a normal body weight. The brain's inability to control energy homeostasis underlies the pathology of hyperphagia and obesity. The brain detects body energy excess and deficit by sensing the levels of circulating metabolic hormones and nutrients and by receiving metabolic information from the periphery via the autonomic nervous system. A specialized neuronal network coordinates energy intake behavior and the metabolic processes affecting energy expenditure. Here, we briefly review neuronal mechanisms by which our body maintains energy balance.

  16. Citrate Metabolism by Pediococcus halophilus

    OpenAIRE

    Kanbe, Chiyuki; Uchida, Kinji

    1987-01-01

    Several strains of non-citrate-metabolizing Pediococcus halophilus have previously been isolated from soy sauce mash or moromi. The factors controlling the metabolism of citrate in soy pediococci were studied. All the soy pediococcal strains tested which failed to decompose citrate did not possess citrate lyase [citrate (pro-3S)-lyase; EC 4.1.3.6] activity. In P. halophilus, citrate lyase was an inducible enzyme, and the optimum pH for activity was 7.0. The metabolism of citrate in P. halophi...

  17. Retinoic acid and iron metabolism

    DEFF Research Database (Denmark)

    Chakraborty, Surajit; Bhattacharyya, Rajasri; Sayal, Kirtimaan

    2014-01-01

    tuberculosis controlling molecules in the days to come. Iron has proven to be essential for pathogenesis of tuberculosis and retinoic acid is known to influence the iron metabolism pathway. Retenoic acid is also known to exhibit antitubercular effect in in vivo system. Therefore there is every possibility...... that retinoic acid by affecting the iron metabolism pathway exhibits its antimycobacterial effect. These aspects are reviewed in the present manuscript for understanding the antimycobacterial role of retinoic acid in the context of iron metabolism and other immunological aspects....

  18. Human metabolic atlas: an online resource for human metabolism.

    Science.gov (United States)

    Pornputtapong, Natapol; Nookaew, Intawat; Nielsen, Jens

    2015-01-01

    Human tissue-specific genome-scale metabolic models (GEMs) provide comprehensive understanding of human metabolism, which is of great value to the biomedical research community. To make this kind of data easily accessible to the public, we have designed and deployed the human metabolic atlas (HMA) website (http://www.metabolicatlas.org). This online resource provides comprehensive information about human metabolism, including the results of metabolic network analyses. We hope that it can also serve as an information exchange interface for human metabolism knowledge within the research community. The HMA consists of three major components: Repository, Hreed (Human REaction Entities Database) and Atlas. Repository is a collection of GEMs for specific human cell types and human-related microorganisms in SBML (System Biology Markup Language) format. The current release consists of several types of GEMs: a generic human GEM, 82 GEMs for normal cell types, 16 GEMs for different cancer cell types, 2 curated GEMs and 5 GEMs for human gut bacteria. Hreed contains detailed information about biochemical reactions. A web interface for Hreed facilitates an access to the Hreed reaction data, which can be easily retrieved by using specific keywords or names of related genes, proteins, compounds and cross-references. Atlas web interface can be used for visualization of the GEMs collection overlaid on KEGG metabolic pathway maps with a zoom/pan user interface. The HMA is a unique tool for studying human metabolism, ranging in scope from an individual cell, to a specific organ, to the overall human body. This resource is freely available under a Creative Commons Attribution-NonCommercial 4.0 International License.

  19. Plant Metabolic Modeling: Achieving New Insight into Metabolism and Metabolic Engineering

    Science.gov (United States)

    Baghalian, Kambiz; Hajirezaei, Mohammad-Reza; Schreiber, Falk

    2014-01-01

    Models are used to represent aspects of the real world for specific purposes, and mathematical models have opened up new approaches in studying the behavior and complexity of biological systems. However, modeling is often time-consuming and requires significant computational resources for data development, data analysis, and simulation. Computational modeling has been successfully applied as an aid for metabolic engineering in microorganisms. But such model-based approaches have only recently been extended to plant metabolic engineering, mainly due to greater pathway complexity in plants and their highly compartmentalized cellular structure. Recent progress in plant systems biology and bioinformatics has begun to disentangle this complexity and facilitate the creation of efficient plant metabolic models. This review highlights several aspects of plant metabolic modeling in the context of understanding, predicting and modifying complex plant metabolism. We discuss opportunities for engineering photosynthetic carbon metabolism, sucrose synthesis, and the tricarboxylic acid cycle in leaves and oil synthesis in seeds and the application of metabolic modeling to the study of plant acclimation to the environment. The aim of the review is to offer a current perspective for plant biologists without requiring specialized knowledge of bioinformatics or systems biology. PMID:25344492

  20. Redesigned Human Metabolic Simulator

    Science.gov (United States)

    Duffield, Bruce; Jeng, Frank; Lange, Kevin

    2008-01-01

    A design has been formulated for a proposed improved version of an apparatus that simulates atmospheric effects of human respiration by introducing controlled amounts of carbon dioxide, water vapor, and heat into the air. Denoted a human metabolic simulator (HMS), the apparatus is used for testing life-support equipment when human test subjects are not available. The prior version of the HMS, to be replaced, was designed to simulate the respiratory effects of as many as four persons. It exploits the catalytic combustion of methyl acetate, for which the respiratory quotient (the molar ratio of carbon dioxide produced to oxygen consumed) is very close to the human respiratory quotient of about 0.86. The design of the improved HMS provides for simulation of the respiratory effects of as many as eight persons at various levels of activity. The design would also increase safety by eliminating the use of combustion. The improved HMS (see figure) would include a computer that would exert overall control. The computer would calculate the required amounts of oxygen removal, carbon dioxide addition, water addition, and heat addition by use of empirical equations for metabolic profiles of respiration and heat. A blower would circulate air between the HMS and a chamber containing a life-support system to be tested. With the help of feedback from a mass flowmeter, the blower speed would be adjusted to regulate the rate of flow according to the number of persons to be simulated and to a temperature-regulation requirement (the air temperature would indirectly depend on the rate of flow, among other parameters). Oxygen would be removed from the circulating air by means of a commercially available molecular sieve configured as an oxygen concentrator. Oxygen, argon, and trace amounts of nitrogen would pass through a bed in the molecular sieve while carbon dioxide, the majority of nitrogen, and other trace gases would be trapped by the bed and subsequently returned to the chamber. If

  1. Testosterone and metabolic syndrome

    Directory of Open Access Journals (Sweden)

    Glenn R Cunningham

    2015-04-01

    Full Text Available Controversies surround the usefulness of identifying patients with the metabolic syndrome (MetS. Many of the components are accepted risk factors for cardiovascular disease (CVD. Although the MetS as defined includes many men with insulin resistance, insulin resistance is not universal. The low total testosterone (TT and sex hormone binding globulin (SHBG levels in these men are best explained by the hyperinsulinism and increased inflammatory cytokines that accompany obesity and increased waist circumference. It is informative that low SHBG levels predict future development of the MetS. Evidence is strong relating low TT levels to CVD in men with and without the MetS; however, the relationship may not be causal. The recommendations of the International Diabetes Federation for managing the MetS include cardiovascular risk assessment, lifestyle changes in diet, exercise, weight reduction and treatment of individual components of the MetS. Unfortunately, it is uncommon to see patients with the MetS lose and maintain a 10% weight loss. Recent reports showing testosterone treatment induced dramatic changes in weight, waist circumference, insulin sensitivity, hemoglobin A1c levels and improvements in each of the components of the MetS are intriguing. While some observational studies have reported that testosterone replacement therapy increases cardiovascular events, the Food and Drug Administration in the United States has reviewed these reports and found them to be seriously flawed. Large, randomized, placebo-controlled trials are needed to provide more definitive data regarding the efficacy and safety of this treatment in middle and older men with the MetS and low TT levels.

  2. Metabolic Syndrome in Nurses

    Directory of Open Access Journals (Sweden)

    María Escasany

    2014-01-01

    Full Text Available Objectives: To estimate the prevalence of metabolic syndrome (MS in female nurses in the Hospital Juan A. Fernandez (HJAF, Buenos Aires, Argentina, and to determine whether work, rest, diet, and health, are predictive of it.Materials and methods: For the first objective, a descriptive, observational and cross-sectional study was conducted, and for the second, a multivariate cross-sectional observational multivariate analysis was made comparing independent samples. A total of 192 nurses were studied between October 2008 and March 2009. They completed a questionnaire that include indicators that could be predictors of MS. Anthropometric measurements, including blood pressure were taken, was well as a blood sample to analyze fasting glucose, HDL-C and plasma triglycerides.Results: It was found that 35% and 41% of nurses were overweight and obese, respectively. A total of 92% had centro-abdominal obesity. The prevalence of MS found was 33.3% (95%CI, 26.7 to 40.5. Those who had this disease were between 53±9 years. Statistically significant differences were found in the bivariate analysis between MS and the variables, age, length of service, time worked during night shift, and academic studies.Conclusions: The prevalence of MS was 64/192 in HJAF nurses (33.3% I 95%CI, 26.7-40.5. There were no statistically significant differences with the indicators of, age, “time worked during night shift”, and “studies”. These results suggest that age is the most important variable in predicting the onset of MS in the population of nurses.

  3. Testosterone and metabolic syndrome.

    Science.gov (United States)

    Cunningham, Glenn R

    2015-01-01

    Controversies surround the usefulness of identifying patients with the metabolic syndrome (MetS). Many of the components are accepted risk factors for cardiovascular disease (CVD). Although the MetS as defined includes many men with insulin resistance, insulin resistance is not universal. The low total testosterone (TT) and sex hormone binding globulin (SHBG) levels in these men are best explained by the hyperinsulinism and increased inflammatory cytokines that accompany obesity and increased waist circumference. It is informative that low SHBG levels predict future development of the MetS. Evidence is strong relating low TT levels to CVD in men with and without the MetS; however, the relationship may not be causal. The recommendations of the International Diabetes Federation for managing the MetS include cardiovascular risk assessment, lifestyle changes in diet, exercise, weight reduction and treatment of individual components of the MetS. Unfortunately, it is uncommon to see patients with the MetS lose and maintain a 10% weight loss. Recent reports showing testosterone treatment induced dramatic changes in weight, waist circumference, insulin sensitivity, hemoglobin A1c levels and improvements in each of the components of the MetS are intriguing. While some observational studies have reported that testosterone replacement therapy increases cardiovascular events, the Food and Drug Administration in the United States has reviewed these reports and found them to be seriously flawed. Large, randomized, placebo-controlled trials are needed to provide more definitive data regarding the efficacy and safety of this treatment in middle and older men with the MetS and low TT levels.

  4. Testosterone and metabolic syndrome

    Science.gov (United States)

    Cunningham, Glenn R

    2015-01-01

    Controversies surround the usefulness of identifying patients with the metabolic syndrome (MetS). Many of the components are accepted risk factors for cardiovascular disease (CVD). Although the MetS as defined includes many men with insulin resistance, insulin resistance is not universal. The low total testosterone (TT) and sex hormone binding globulin (SHBG) levels in these men are best explained by the hyperinsulinism and increased inflammatory cytokines that accompany obesity and increased waist circumference. It is informative that low SHBG levels predict future development of the MetS. Evidence is strong relating low TT levels to CVD in men with and without the MetS; however, the relationship may not be causal. The recommendations of the International Diabetes Federation for managing the MetS include cardiovascular risk assessment, lifestyle changes in diet, exercise, weight reduction and treatment of individual components of the MetS. Unfortunately, it is uncommon to see patients with the MetS lose and maintain a 10% weight loss. Recent reports showing testosterone treatment induced dramatic changes in weight, waist circumference, insulin sensitivity, hemoglobin A1c levels and improvements in each of the components of the MetS are intriguing. While some observational studies have reported that testosterone replacement therapy increases cardiovascular events, the Food and Drug Administration in the United States has reviewed these reports and found them to be seriously flawed. Large, randomized, placebo-controlled trials are needed to provide more definitive data regarding the efficacy and safety of this treatment in middle and older men with the MetS and low TT levels. PMID:25652634

  5. Context-dependent metabolic networks

    CERN Document Server

    Beguerisse-Díaz, Mariano; Oyarzún, Diego; Picó, Jesús; Barahona, Mauricio

    2016-01-01

    Cells adapt their metabolism to survive changes in their environment. We present a framework for the construction and analysis of metabolic reaction networks that can be tailored to reflect different environmental conditions. Using context-dependent flux distributions from Flux Balance Analysis (FBA), we produce directed networks with weighted links representing the amount of metabolite flowing from a source reaction to a target reaction per unit time. Such networks are analyzed with tools from network theory to reveal salient features of metabolite flows in each biological context. We illustrate our approach with the directed network of the central carbon metabolism of Escherichia coli, and study its properties in four relevant biological scenarios. Our results show that both flow and network structure depend drastically on the environment: networks produced from the same metabolic model in different contexts have different edges, components, and flow communities, capturing the biological re-routing of metab...

  6. Metabolic control of renin secretion.

    Science.gov (United States)

    Peti-Peterdi, János; Gevorgyan, Haykanush; Lam, Lisa; Riquier-Brison, Anne

    2013-01-01

    One emerging topic in renin-angiotensin system (RAS) research is the direct local control of renin synthesis and release by endogenous metabolic intermediates. During the past few years, our laboratory has characterized the localization and signaling of the novel metabolic receptor GPR91 in the normal and diabetic kidney and established GPR91 as a new, direct link between high glucose and RAS activation in diabetes. GPR91 (also called SUCNR1) binds tricarboxylic acid (TCA) cycle intermediate succinate which can rapidly accumulate in the local tissue environment when energy supply and demand are out of balance. In a variety of physiological and pathological conditions associated with metabolic stress, succinate signaling via GPR91 appears to be an important mediator or modulator of renin secretion. This review summarizes our current knowledge on the control of renin release by molecules of endogenous metabolic pathways with the main focus on succinate/GPR91.

  7. Gait Dynamics and Locomotor Metabolism

    Science.gov (United States)

    2009-05-01

    field settings from simple technologies such as gps monitors and pedometers. 15. SUBJECT TERMS Locomotion, gait, metabolism, body size, load...a reduction in exercise intensity. REFERENCES: 1. Alexander, RM. Sprinting and endurance for runners and cyclists . American Journal of

  8. Metabolic Resistance in Bed Bugs

    Directory of Open Access Journals (Sweden)

    Omprakash Mittapalli

    2011-03-01

    Full Text Available Blood-feeding insects have evolved resistance to various insecticides (organochlorines, pyrethroids, carbamates, etc. through gene mutations and increased metabolism. Bed bugs (Cimex lectularius are hematophagous ectoparasites that are poised to become one of the major pests in households throughout the United States. Currently, C. lectularius has attained a high global impact status due to its sudden and rampant resurgence. Resistance to pesticides is one factor implicated in this phenomenon. Although much emphasis has been placed on target sensitivity, little to no knowledge is available on the role of key metabolic players (e.g., cytochrome P450s and glutathione S-transferases towards pesticide resistance in C. lectularius. In this review, we discuss different modes of resistance (target sensitivity, penetration resistance, behavioral resistance, and metabolic resistance with more emphasis on metabolic resistance.

  9. Histone variants and lipid metabolism

    NARCIS (Netherlands)

    Borghesan, Michela; Mazzoccoli, Gianluigi; Sheedfar, Fareeba; Oben, Jude; Pazienza, Valerio; Vinciguerra, Manlio

    2014-01-01

    Within nucleosomes, canonical histones package the genome, but they can be opportunely replaced with histone variants. The incorporation of histone variants into the nucleosome is a chief cellular strategy to regulate transcription and cellular metabolism. In pathological terms, cellular steatosis

  10. Metabolism and biochemistry in hypogravity

    Science.gov (United States)

    Leach, Carolyn S.

    The headward shift of body fluid and increase in stress-related hormones that occur in hypogravity bring about a number of changes in metabolism and biochemistry of the human body. Such alterations may have important effects on health during flight and during a recovery period after return to Earth. Body fluid and electrolytes are lost, and blood levels of several hormones that control metabolism are altered during space flight. Increased serum calcium may lead to an increased risk of renal stone formation during flight, and altered drug metabolism could influence the efficacy of therapeutic agents. Orthostatic intolerance and an increased risk of fracturing weakened bones are concerns at landing. It is important to understand biochemistry and metabolism in hypogravity so that clinically important developments can be anticipated and prevented or ameliorated.

  11. Metabolic syndrome and periodontal disease

    Directory of Open Access Journals (Sweden)

    Bharti Vipin

    2009-01-01

    Full Text Available It is important for a dentist to be well informed and updated on the latest research on the association of oral and systemic health. Of late, the metabolic syndrome has gained importance in dental literature, and metabolic syndrome and periodontal disease have been linked. Metabolic syndrome (MeS is a group of three or more (up to five interrelated metabolic abnormalities, which increases the risk of cardiovascular morbidity and mortality. Also, both MeS and periodontal disease may be linked through a common pathophysiological pathway. Some studies have been conducted to show such an association and additional studies are required to establish this association. A dental surgeon can play a major role in evaluating patients with MeS and thus prevent the development of overt cardiovascular disease.

  12. Metabolism and biochemistry in hypogravity

    Science.gov (United States)

    Leach, Carolyn S.

    1991-01-01

    The headward shift of body fluid and increase in stress-related hormones that occur in hypogravity bring about a number of changes in metabolism and biochemistry of the human body. Such alterations may have important effects on health during flight and during a recovery period after return to earth. Body fluid and electrolytes are lost, and blood levels of several hormones that control metabolism are altered during space flight. Increased serum calcium may lead to an increased risk of renal stone formation during flight, and altered drug metabolism could influence the efficacy of therapeutic agents. Orthostatic intolerance and an increased risk of fracturing weakened bones are concerns at landing. It is important to understand biochemistry and metabolism in hypogravity so that clinically important developments can be anticipated and prevented or ameliorated.

  13. Multidimensional optimality of microbial metabolism.

    Science.gov (United States)

    Schuetz, Robert; Zamboni, Nicola; Zampieri, Mattia; Heinemann, Matthias; Sauer, Uwe

    2012-05-04

    Although the network topology of metabolism is well known, understanding the principles that govern the distribution of fluxes through metabolism lags behind. Experimentally, these fluxes can be measured by (13)C-flux analysis, and there has been a long-standing interest in understanding this functional network operation from an evolutionary perspective. On the basis of (13)C-determined fluxes from nine bacteria and multi-objective optimization theory, we show that metabolism operates close to the Pareto-optimal surface of a three-dimensional space defined by competing objectives. Consistent with flux data from evolved Escherichia coli, we propose that flux states evolve under the trade-off between two principles: optimality under one given condition and minimal adjustment between conditions. These principles form the forces by which evolution shapes metabolic fluxes in microorganisms' environmental context.

  14. Can you boost your metabolism?

    Science.gov (United States)

    ... M, Jeukendrup A, King NA, Blundell JE. The relationship between substrate metabolism, exercise, and appetite control: Does glycogen availability influence the motivation to eat, energy intake or food choice? Sports Med . 2011;41(6):507-521. PMID: 21615191 www. ...

  15. Metabolic Resistance in Bed Bugs.

    Science.gov (United States)

    Mamidala, Praveen; Jones, Susan C; Mittapalli, Omprakash

    2011-03-18

    Blood-feeding insects have evolved resistance to various insecticides (organochlorines, pyrethroids, carbamates, etc.) through gene mutations and increased metabolism. Bed bugs (Cimex lectularius) are hematophagous ectoparasites that are poised to become one of the major pests in households throughout the United States. Currently, C. lectularius has attained a high global impact status due to its sudden and rampant resurgence. Resistance to pesticides is one factor implicated in this phenomenon. Although much emphasis has been placed on target sensitivity, little to no knowledge is available on the role of key metabolic players (e.g., cytochrome P450s and glutathione S-transferases) towards pesticide resistance in C. lectularius. In this review, we discuss different modes of resistance (target sensitivity, penetration resistance, behavioral resistance, and metabolic resistance) with more emphasis on metabolic resistance.

  16. Adipose Tissue Metabolism During Hypobaria

    Directory of Open Access Journals (Sweden)

    D. P. Chattopadhyay

    1974-10-01

    Full Text Available Possible factors affecting the metabolism of adipose tissue under hypobaric conditions have been reviewed. The hormonal changes brought into play under hypoxic stress generally stress generally increase the adipose tissue lipolysis.

  17. Metabolic-hydaulic model Data

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The data contained in this workbook were compiled to investigate the relationship between hydrology of the Colorado River and ecosystem metabolism parameters (i.e.,...

  18. Carbohydrate Metabolism in Submariner Personnel

    Science.gov (United States)

    1983-06-01

    metabolism the Wilkerson Point System, for glucose values, used in conjunction with patterns of insulin response described by Kraft(4) serves as the means...amount of exercise and carbohydrate metabolism characteristics occurred in both submariners and non-submariners. An inverse relationship also seems to...individuals(7). In the present study a significant negative correlation was also found between exercise vs one and two hour postprandial glucose and two hour

  19. Tailoring the metabolism against mutations

    Science.gov (United States)

    Gulbahce, Natali; Motter, Adilson E.; Almaas, Eivind; Barabasi, Albert Laszlo

    2008-03-01

    In the post-genomic era, organisms can be modelled at the whole-cell level in silico via steady state methods to describe their metabolic capabilities. We use two such methods, Flux Balance Analysis and Minimization of Metabolic Adjustment to explore the behavior of cells (of E. coli and S. cerevisiae) after severe mutations. We propose experimentally feasible ways of modifying the underlying biochemical reaction network of a mutant cell such that cell functionality, in particular growth rate, is significantly improved.

  20. Evolution of metabolic network organization

    Directory of Open Access Journals (Sweden)

    Bonchev Danail

    2010-05-01

    Full Text Available Abstract Background Comparison of metabolic networks across species is a key to understanding how evolutionary pressures shape these networks. By selecting taxa representative of different lineages or lifestyles and using a comprehensive set of descriptors of the structure and complexity of their metabolic networks, one can highlight both qualitative and quantitative differences in the metabolic organization of species subject to distinct evolutionary paths or environmental constraints. Results We used a novel representation of metabolic networks, termed network of interacting pathways or NIP, to focus on the modular, high-level organization of the metabolic capabilities of the cell. Using machine learning techniques we identified the most relevant aspects of cellular organization that change under evolutionary pressures. We considered the transitions from prokarya to eukarya (with a focus on the transitions among the archaea, bacteria and eukarya, from unicellular to multicellular eukarya, from free living to host-associated bacteria, from anaerobic to aerobic, as well as the acquisition of cell motility or growth in an environment of various levels of salinity or temperature. Intuitively, we expect organisms with more complex lifestyles to have more complex and robust metabolic networks. Here we demonstrate for the first time that such organisms are not only characterized by larger, denser networks of metabolic pathways but also have more efficiently organized cross communications, as revealed by subtle changes in network topology. These changes are unevenly distributed among metabolic pathways, with specific categories of pathways being promoted to more central locations as an answer to environmental constraints. Conclusions Combining methods from graph theory and machine learning, we have shown here that evolutionary pressures not only affects gene and protein sequences, but also specific details of the complex wiring of functional modules