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Sample records for hydrogenases related genes

  1. Hydrogenase Gene Distribution and H2 Consumption Ability within the Thiomicrospira Lineage.

    PubMed

    Hansen, Moritz; Perner, Mirjam

    2016-01-01

    Thiomicrospira were originally characterized as sulfur-oxidizing chemolithoautotrophs. Attempts to grow them on hydrogen failed for many years. Only recently we demonstrated hydrogen consumption among two of three tested Thiomicrospira and posited that hydrogen consumption may be more widespread among Thiomicrospira than previously assumed. Here, we investigate and compare the hydrogen consumption ability and the presence of group 1 [NiFe]-hydrogenase genes (enzyme catalyzes H2↔2H(+) + 2e(-)) for sixteen different Thiomicrospira species. Seven of these Thiomicrospira species encoded group 1 [NiFe]-hydrogenase genes and five of these species could also consume hydrogen. All Thiomicrospira species exhibiting hydrogen consumption were from hydrothermal vents along the Mid-Atlantic ridge or Eastern Pacific ridges. The tested Thiomicrospira from Mediterranean and Western Pacific vents could not consume hydrogen. The [NiFe]-hydrogenase genes were categorized into two clusters: those resembling the hydrogenase from Hydrogenovibrio are in cluster I and are related to those from Alpha- and other Gammaproteobacteria. In cluster II, hydrogenases found exclusively in Thiomicrospira crunogena strains are combined and form a monophyletic group with those from Epsilonproteobacteria suggesting they were acquired through horizontal gene transfer. Hydrogen consumption appears to be common among some Thiomicrospira, given that five of the tested sixteen strains carried this trait. The hydrogen consumption ability expands their competitiveness within an environment.

  2. Hydrogenase Gene Distribution and H2 Consumption Ability within the Thiomicrospira Lineage

    PubMed Central

    Hansen, Moritz; Perner, Mirjam

    2016-01-01

    Thiomicrospira were originally characterized as sulfur-oxidizing chemolithoautotrophs. Attempts to grow them on hydrogen failed for many years. Only recently we demonstrated hydrogen consumption among two of three tested Thiomicrospira and posited that hydrogen consumption may be more widespread among Thiomicrospira than previously assumed. Here, we investigate and compare the hydrogen consumption ability and the presence of group 1 [NiFe]-hydrogenase genes (enzyme catalyzes H2↔2H+ + 2e-) for sixteen different Thiomicrospira species. Seven of these Thiomicrospira species encoded group 1 [NiFe]-hydrogenase genes and five of these species could also consume hydrogen. All Thiomicrospira species exhibiting hydrogen consumption were from hydrothermal vents along the Mid-Atlantic ridge or Eastern Pacific ridges. The tested Thiomicrospira from Mediterranean and Western Pacific vents could not consume hydrogen. The [NiFe]-hydrogenase genes were categorized into two clusters: those resembling the hydrogenase from Hydrogenovibrio are in cluster I and are related to those from Alpha- and other Gammaproteobacteria. In cluster II, hydrogenases found exclusively in Thiomicrospira crunogena strains are combined and form a monophyletic group with those from Epsilonproteobacteria suggesting they were acquired through horizontal gene transfer. Hydrogen consumption appears to be common among some Thiomicrospira, given that five of the tested sixteen strains carried this trait. The hydrogen consumption ability expands their competitiveness within an environment. PMID:26903978

  3. Hydrogenase Gene Distribution and H2 Consumption Ability within the Thiomicrospira Lineage.

    PubMed

    Hansen, Moritz; Perner, Mirjam

    2016-01-01

    Thiomicrospira were originally characterized as sulfur-oxidizing chemolithoautotrophs. Attempts to grow them on hydrogen failed for many years. Only recently we demonstrated hydrogen consumption among two of three tested Thiomicrospira and posited that hydrogen consumption may be more widespread among Thiomicrospira than previously assumed. Here, we investigate and compare the hydrogen consumption ability and the presence of group 1 [NiFe]-hydrogenase genes (enzyme catalyzes H2↔2H(+) + 2e(-)) for sixteen different Thiomicrospira species. Seven of these Thiomicrospira species encoded group 1 [NiFe]-hydrogenase genes and five of these species could also consume hydrogen. All Thiomicrospira species exhibiting hydrogen consumption were from hydrothermal vents along the Mid-Atlantic ridge or Eastern Pacific ridges. The tested Thiomicrospira from Mediterranean and Western Pacific vents could not consume hydrogen. The [NiFe]-hydrogenase genes were categorized into two clusters: those resembling the hydrogenase from Hydrogenovibrio are in cluster I and are related to those from Alpha- and other Gammaproteobacteria. In cluster II, hydrogenases found exclusively in Thiomicrospira crunogena strains are combined and form a monophyletic group with those from Epsilonproteobacteria suggesting they were acquired through horizontal gene transfer. Hydrogen consumption appears to be common among some Thiomicrospira, given that five of the tested sixteen strains carried this trait. The hydrogen consumption ability expands their competitiveness within an environment. PMID:26903978

  4. Process and genes for expression and overexpression of active [FeFe] hydrogenases

    DOEpatents

    Seibert, Michael; King, Paul W; Ghirardi, Maria Lucia; Posewitz, Matthew C; Smolinski, Sharon L

    2014-09-16

    A process for expression of active [FeFe]-hydrogenase in a host organism that does not contain either the structural gene(s) for [FeFe]-hydrogenases and/or homologues for the maturation genes HydE, HydF and HyG, comprising: cloning the structural hydrogenase gene(s) and/or the maturation genes HydE, HydF and HydG from an organisms that contains these genes into expression plasmids; transferring the plasmids into an organism that lacks a native [FeFe]-hydrogenase or that has a disrupted [FeFe]-hydrogenase and culturing it aerobically; and inducing anaerobiosis to provide [FeFe] hydrogenase biosynthesis and H?2#191 production.

  5. Characterization of the CO-induced, CO-tolerant hydrogenase from Rhodospirillum rubrum and the gene encoding the large subunit of the enzyme.

    PubMed Central

    Fox, J D; Kerby, R L; Roberts, G P; Ludden, P W

    1996-01-01

    In the presence of carbon monoxide, the photosynthetic bacterium Rhodospirillum rubrum induces expression of proteins which allow the organism to metabolize carbon monoxide in the net reaction CO + H2O --> CO2 + H2. These proteins include the enzymes carbon monoxide dehydrogenase (CODH) and a CO-tolerant hydrogenase. In this paper, we present the complete amino acid sequence for the large subunit of this hydrogenase and describe the properties of the crude enzyme in relation to other known hydrogenases. The amino acid sequence deduced from the CO-induced hydrogenase large-subunit gene (cooH) shows significant similarity to large subunits of other Ni-Fe hydrogenases. The closest similarity is with HycE (58% similarity and 37% identity) from Escherichia coli, which is the large subunit of an Ni-Fe hydrogenase (isoenzyme 3). The properties of the CO-induced hydrogenase are unique. It is exceptionally resistant to inhibition by carbon monoxide. It also exhibits a very high ratio of H2 evolution to H2 uptake activity compared with other known hydrogenases. The CO-induced hydrogenase is tightly membrane bound, and its inhibition by nonionic detergents is described. Finally, the presence of nickel in the hydrogenase is addressed. Analysis of wild-type R. rubrum grown on nickel-depleted medium indicates a requirement for nickel for hydrogenase activity. However, analysis of strain UR294 (cooC insertion mutant defective in nickel insertion into CODH) shows that independent nickel insertion mechanisms are utilized by hydrogenase and CODH. CooH lacks the C-terminal peptide that is found in other Ni-Fe hydrogenases; in other systems, this peptide is cleaved during Ni processing. PMID:8626276

  6. Novel [NiFe]- and [FeFe]-hydrogenase gene transcripts indicative of active facultative aerobes and obligate anaerobes in earthworm gut contents.

    PubMed

    Schmidt, Oliver; Wüst, Pia K; Hellmuth, Susanne; Borst, Katharina; Horn, Marcus A; Drake, Harold L

    2011-09-01

    The concomitant occurrence of molecular hydrogen (H(2)) and organic acids along the alimentary canal of the earthworm is indicative of ongoing fermentation during gut passage. Fermentative H(2) production is catalyzed by [FeFe]-hydrogenases and group 4 [NiFe]-hydrogenases in obligate anaerobes (e.g., Clostridiales) and facultative aerobes (e.g., Enterobacteriaceae), respectively, functional groups that might respond differently to contrasting redox conditions. Thus, the objectives of this study were to assess the redox potentials of the alimentary canal of Lumbricus terrestris and analyze the hydrogenase transcript diversities of H(2) producers in glucose-supplemented gut content microcosms. Although redox potentials in the core of the alimentary canal were variable on an individual worm basis, average redox potentials were similar. The lowest redox potentials occurred in the foregut and midgut regions, averaging 40 and 110 mV, respectively. Correlation plots between hydrogenase amino acid sequences and 16S rRNA gene sequences indicated that closely related hydrogenases belonged to closely related taxa, whereas distantly related hydrogenases did not necessarily belong to distantly related taxa. Of 178 [FeFe]-hydrogenase gene transcripts, 177 clustered in 12 Clostridiales-affiliated operational taxonomic units, the majority of which were indicative of heretofore unknown hydrogenases. Of 86 group 4 [NiFe]-hydrogenase gene transcripts, 79% and 21% were affiliated with organisms in the Enterobacteriaceae and Aeromonadaceae, respectively. The collective results (i) suggest that fermenters must cope with variable and moderately oxidative redox conditions along the alimentary canal, (ii) demonstrate that heretofore undetected hydrogenases are present in the earthworm gut, and (iii) corroborate previous findings implicating Clostridiaceae and Enterobacteriaceae as active fermentative taxa in earthworm gut content. PMID:21784904

  7. Novel [NiFe]- and [FeFe]-Hydrogenase Gene Transcripts Indicative of Active Facultative Aerobes and Obligate Anaerobes in Earthworm Gut Contents▿†

    PubMed Central

    Schmidt, Oliver; Wüst, Pia K.; Hellmuth, Susanne; Borst, Katharina; Horn, Marcus A.; Drake, Harold L.

    2011-01-01

    The concomitant occurrence of molecular hydrogen (H2) and organic acids along the alimentary canal of the earthworm is indicative of ongoing fermentation during gut passage. Fermentative H2 production is catalyzed by [FeFe]-hydrogenases and group 4 [NiFe]-hydrogenases in obligate anaerobes (e.g., Clostridiales) and facultative aerobes (e.g., Enterobacteriaceae), respectively, functional groups that might respond differently to contrasting redox conditions. Thus, the objectives of this study were to assess the redox potentials of the alimentary canal of Lumbricus terrestris and analyze the hydrogenase transcript diversities of H2 producers in glucose-supplemented gut content microcosms. Although redox potentials in the core of the alimentary canal were variable on an individual worm basis, average redox potentials were similar. The lowest redox potentials occurred in the foregut and midgut regions, averaging 40 and 110 mV, respectively. Correlation plots between hydrogenase amino acid sequences and 16S rRNA gene sequences indicated that closely related hydrogenases belonged to closely related taxa, whereas distantly related hydrogenases did not necessarily belong to distantly related taxa. Of 178 [FeFe]-hydrogenase gene transcripts, 177 clustered in 12 Clostridiales-affiliated operational taxonomic units, the majority of which were indicative of heretofore unknown hydrogenases. Of 86 group 4 [NiFe]-hydrogenase gene transcripts, 79% and 21% were affiliated with organisms in the Enterobacteriaceae and Aeromonadaceae, respectively. The collective results (i) suggest that fermenters must cope with variable and moderately oxidative redox conditions along the alimentary canal, (ii) demonstrate that heretofore undetected hydrogenases are present in the earthworm gut, and (iii) corroborate previous findings implicating Clostridiaceae and Enterobacteriaceae as active fermentative taxa in earthworm gut content. PMID:21784904

  8. Genetic diversity and expression of the [NiFe] hydrogenase large-subunit gene of Desulfovibrio spp. in environmental samples.

    PubMed Central

    Wawer, C; Jetten, M S; Muyzer, G

    1997-01-01

    The genetic diversity and expression of the [NiFe] hydrogenase large-subunit gene of Desulfovibrio spp. in environmental samples were determined in order to show in parallel the existing and active members of Desulfovibrio populations. DNA and total RNA were extracted from different anaerobic bioreactor samples; RNA was transcribed into cDNA. Subsequently, PCR was performed to amplify a ca.-440-bp fragment of the [NiFe] hydrogenase large-subunit gene and its mRNA. Denaturing gradient gel electrophoresis analysis was used to separate the PCR products according to their sequence and thereby to visualize the individual community members. Desulfovibrio strains corresponding to amplified [NiFe] hydrogenase transcripts were regarded as metabolically active, because in pure cultures transcripts were detectable in exponentially growing cells but not in cultures in the stationary phase. DNA sequencing and comparative sequence analysis were used to identify the detected organisms on the basis of their [NiFe] hydrogenase sequences. The genes of characterized Desulfovibrio spp. showed a considerable extent of divergence (ca. 30%), whereas sequences obtained from bacterial populations of the bioreactors showed a low level of variation and indicated the coexistence of closely related strains probably belonging to the species Desulfovibrio sulfodismutans. Under methanogenic conditions, all detected populations were active; under denitrifying conditions, no [NiFe] hydrogenase mRNA was visible. Changes in activity and composition of Desulfovibrio populations caused by changes in the environmental conditions could be monitored by using the approach described in this study. PMID:9361423

  9. Differences in Hydrogenase Gene Expression between Methanosarcina acetivorans and Methanosarcina barkeri▿ †

    PubMed Central

    Guss, Adam M.; Kulkarni, Gargi; Metcalf, William W.

    2009-01-01

    Methanosarcina acetivorans C2A encodes three putative hydrogenases, including one cofactor F420-linked (frh) and two methanophenazine-linked (vht) enzymes. Comparison of the amino acid sequences of these putative hydrogenases to those of Methanosarcina barkeri and Methanosarcina mazei shows that each predicted subunit contains all the known residues essential for hydrogenase function. The DNA sequences upstream of the genes in M. acetivorans were aligned with those in other Methanosarcina species to identify conserved transcription and translation signals. The M. acetivorans vht promoter region is well conserved among the sequenced Methanosarcina species, while the second vht-type homolog (here called vhx) and frh promoters have only limited similarity. To experimentally determine whether these promoters are functional in vivo, we constructed and characterized both M. acetivorans and M. barkeri strains carrying reporter gene fusions to each of the M. acetivorans and M. barkeri hydrogenase promoters. Generally, the M. acetivorans gene fusions are not expressed in either organism, suggesting that cis-acting mutations inactivated the M. acetivorans promoters. The M. barkeri hydrogenase gene fusions, on the other hand, are expressed in both organisms, indicating that M. acetivorans possesses the machinery to express hydrogenases, although it does not express its own hydrogenases. These data are consistent with specific inactivation of the M. acetivorans hydrogenase promoters and highlight the importance of testing hypotheses generated by using genomic data. PMID:19201801

  10. Regulation of uptake hydrogenase and effects of hydrogen utilization on gene expression in Rhodopseudomonas palustris.

    PubMed

    Rey, Federico E; Oda, Yasuhiro; Harwood, Caroline S

    2006-09-01

    Rhodopseudomonas palustris is a purple, facultatively phototrophic bacterium that uses hydrogen gas as an electron donor for carbon dioxide fixation during photoautotrophic growth or for ammonia synthesis during nitrogen fixation. It also uses hydrogen as an electron supplement to enable the complete assimilation of oxidized carbon compounds, such as malate, into cell material during photoheterotrophic growth. The R. palustris genome predicts a membrane-bound nickel-iron uptake hydrogenase and several regulatory proteins to control hydrogenase synthesis. There is also a novel sensor kinase gene (RPA0981) directly adjacent to the hydrogenase gene cluster. Here we show that the R. palustris regulatory sensor hydrogenase HupUV acts in conjunction with the sensor kinase-response regulator protein pair HoxJ-HoxA to activate hydrogenase expression in response to hydrogen gas. Transcriptome analysis indicated that the HupUV-HoxJA regulatory system also controls the expression of genes encoding a predicted dicarboxylic acid transport system, a putative formate transporter, and a glutamine synthetase. RPA0981 had a small effect in repressing hydrogenase synthesis. We also determined that the two-component system RegS-RegR repressed expression of the uptake hydrogenase, probably in response to changes in intracellular redox status. Transcriptome analysis indicated that about 30 genes were differentially expressed in R. palustris cells that utilized hydrogen when growing photoheterotrophically on malate under nitrogen-fixing conditions compared to a mutant strain that lacked uptake hydrogenase. From this it appears that the recycling of reductant in the form of hydrogen does not have extensive nonspecific effects on gene expression in R. palustris. PMID:16923881

  11. Iron-dependent hydrogenases of Entamoeba histolytica and Giardia lamblia: activity of the recombinant entamoebic enzyme and evidence for lateral gene transfer.

    PubMed

    Nixon, Julie E J; Field, Jessica; McArthur, Andrew G; Sogin, Mitchell L; Yarlett, Nigel; Loftus, Brendan J; Samuelson, John

    2003-02-01

    Entamoeba histolytica and Spironucleus barkhanus have genes that encode short iron-dependent hydrogenases (Fe-hydrogenases), even though these protists lack hydrogenosomes. To understand better the biochemistry of the protist Fe-hydrogenases, we prepared a recombinant E. histolytica short Fe-hydrogenase and measured its activity in vitro. A Giardia lamblia gene encoding a short Fe-hydrogenase was identified from shotgun genomic sequences, and RT-PCR showed that cultured entamoebas and giardias transcribe short Fe-hydrogenase mRNAs. A second E. histolytica gene, which encoded a long Fe-hydrogenase, was identified from shotgun genomic sequences. Phylogenetic analyses suggested that the short Fe-hydrogenase genes of entamoeba and diplomonads share a common ancestor, while the long Fe-hydrogenase gene of entamoeba appears to have been laterally transferred from a bacterium. These results are discussed in the context of competing ideas for the origins of genes encoding fermentation enzymes of these protists.

  12. Distribution of hydrogenase genes in Desulforvibrio spp. and their use in identification of species from the oil field environment

    SciTech Connect

    Voordouw, G.; Niviere, V. ); Ferris, F.G. ); Fedorak, P.M.; Westlake, D.W.S. )

    1990-12-01

    The distribution of genes for (Fe), (NiFe), and (NiFeSe) hydrogenases was determined for 22 Desulfovibrio species. The genes for (NiFe) hydrogenase were present in all species, whereas those for the (Fe) and (NiFeSe) hydrogenases had a more limited distribution. Sulfate-reducing bacteria from 16S rRNA groups other than the genus Desulfovibrio did not react with the (NiFe) hydrogenase gene probe, which could be used to identify different Desulfovibrio species in oil field samples following growth on lactate-sulfate medium.

  13. Flow-FISH analysis and isolation of clostridial strains in an anaerobic semi-solid bio-hydrogen producing system by hydrogenase gene target.

    PubMed

    Jen, Chang Jui; Chou, Chia-Hung; Hsu, Ping-Chi; Yu, Sian-Jhong; Chen, Wei-En; Lay, Jiunn-Jyi; Huang, Chieh-Chen; Wen, Fu-Shyan

    2007-04-01

    By using hydrogenase gene-targeted polymerase chain reaction (PCR) and reverse transcriptase PCR (RT-PCR), the predominant clostridial hydrogenase that may have contributed to biohydrogen production in an anaerobic semi-solid fermentation system has been monitored. The results revealed that a Clostridium pasteurianum-like hydrogenase gene sequence can be detected by both PCR and RT-PCR and suggested that the bacterial strain possessing this specific hydrogenase gene was dominant in hydrogenase activity and population. Whereas another Clostridium saccharobutylicum-like hydrogenase gene can be detected only by RT-PCR and suggest that the bacterial strain possessing this specific hydrogenase gene may be less dominant in population. In this study, hydrogenase gene-targeted fluorescence in situ hybridization (FISH) and flow cytometry analysis confirmed that only 6.6% of the total eubacterial cells in a hydrogen-producing culture were detected to express the C. saccharobutylicum-like hydrogenase, whereas the eubacteria that expressed the C. pasteurianum-like hydrogenase was 25.6%. A clostridial strain M1 possessing the identical nucleotide sequences of the C. saccharobutylicum-like hydrogenase gene was then isolated and identified as Clostridium butyricum based on 16S rRNA sequence. Comparing to the original inoculum with mixed microflora, either using C. butyricum M1 as the only inoculum or co-culturing with a Bacillus thermoamylovorans isolate will guarantee an effective and even better production of hydrogen from brewery yeast waste.

  14. Relating diffusion along the substrate tunnel and oxygen sensitivity in hydrogenase.

    PubMed

    Liebgott, Pierre-Pol; Leroux, Fanny; Burlat, Bénédicte; Dementin, Sébastien; Baffert, Carole; Lautier, Thomas; Fourmond, Vincent; Ceccaldi, Pierre; Cavazza, Christine; Meynial-Salles, Isabelle; Soucaille, Philippe; Fontecilla-Camps, Juan Carlos; Guigliarelli, Bruno; Bertrand, Patrick; Rousset, Marc; Léger, Christophe

    2010-01-01

    In hydrogenases and many other redox enzymes, the buried active site is connected to the solvent by a molecular channel whose structure may determine the enzyme's selectivity with respect to substrate and inhibitors. The role of these channels has been addressed using crystallography and molecular dynamics, but kinetic data are scarce. Using protein film voltammetry, we determined and then compared the rates of inhibition by CO and O2 in ten NiFe hydrogenase mutants and two FeFe hydrogenases. We found that the rate of inhibition by CO is a good proxy of the rate of diffusion of O2 toward the active site. Modifying amino acids whose side chains point inside the tunnel can slow this rate by orders of magnitude. We quantitatively define the relations between diffusion, the Michaelis constant for H2 and rates of inhibition, and we demonstrate that certain enzymes are slowly inactivated by O2 because access to the active site is slow.

  15. Discovery of [NiFe] hydrogenase genes in metagenomic DNA: cloning and heterologous expression in Thiocapsa roseopersicina.

    PubMed

    Maróti, Gergely; Tong, Yingkai; Yooseph, Shibu; Baden-Tillson, Holly; Smith, Hamilton O; Kovács, Kornél L; Frazier, Marvin; Venter, J Craig; Xu, Qing

    2009-09-01

    Using a metagenomics approach, we have cloned a piece of environmental DNA from the Sargasso Sea that encodes an [NiFe] hydrogenase showing 60% identity to the large subunit and 64% to the small subunit of a Thiocapsa roseopersicina O2-tolerant [NiFe] hydrogenase. The DNA sequence of the hydrogenase identified by the metagenomic approach was subsequently found to be 99% identical to the hyaA and hyaB genes of an Alteromonas macleodii hydrogenase, indicating that it belongs to the Alteromonas clade. We were able to express our new Alteromonas hydrogenase in T. roseopersicina. Expression was accomplished by coexpressing only two accessory genes, hyaD and hupH, without the need to express any of the hyp accessory genes (hypABCDEF). These results suggest that the native accessory proteins in T. roseopersicina could substitute for the Alteromonas counterparts that are absent in the host to facilitate the assembly of a functional Alteromonas hydrogenase. To further compare the complex assembly machineries of these two [NiFe] hydrogenases, we performed complementation experiments by introducing the new Alteromonas hyaD gene into the T. roseopersicina hynD mutant. Interestingly, Alteromonas endopeptidase HyaD could complement T. roseopersicina HynD to cleave endoproteolytically the C-terminal end of the T. roseopersicina HynL hydrogenase large subunit and activate the enzyme. This study refines our knowledge on the selectivity and pleiotropy of the elements of the [NiFe] hydrogenase assembly machineries. It also provides a model for functionally analyzing novel enzymes from environmental microbes in a culture-independent manner. PMID:19633107

  16. Evolutionary Significance of an Algal Gene Encoding an [FeFe]-Hydrogenase with F-Domain Homology and Hydrogenase Activity in Chlorella Variabilis NC64A

    SciTech Connect

    Meuser, J. E.; Boyd, E. S.; Ananyev, G.; Karns, D.; Radakovits, R.; Murthy, U. M. N.; Ghirardi, M. L.; Dismukes, G. C.; Peters, J. W.; Posewitz, M. C.

    2011-10-01

    [FeFe]-hydrogenases (HYDA) link the production of molecular H{sub 2} to anaerobic metabolism in many green algae. Similar to Chlamydomonas reinhardtii, Chlorella variabilis NC64A (Trebouxiophyceae, Chlorophyta) exhibits [FeFe]-hydrogenase (HYDA) activity during anoxia. In contrast to C. reinhardtii and other chlorophycean algae, which contain hydrogenases with only the HYDA active site (H-cluster), C. variabilis NC64A is the only known green alga containing HYDA genes encoding accessory FeS cluster-binding domains (F-cluster). cDNA sequencing confirmed the presence of F-cluster HYDA1 mRNA transcripts, and identified deviations from the in silico splicing models. We show that HYDA activity in C. variabilis NC64A is coupled to anoxic photosynthetic electron transport (PSII linked, as well as PSII-independent) and dark fermentation. We also show that the in vivo H{sub 2}-photoproduction activity observed is as O2 sensitive as in C. reinhardtii. The two C. variabilis NC64A HYDA sequences are similar to homologs found in more deeply branching bacteria (Thermotogales), diatoms, and heterotrophic flagellates, suggesting that an F-cluster HYDA is the ancestral enzyme in algae. Phylogenetic analysis indicates that the algal HYDA H-cluster domains are monophyletic, suggesting that they share a common origin, and evolved from a single ancestral F-cluster HYDA. Furthermore, phylogenetic reconstruction indicates that the multiple algal HYDA paralogs are the result of gene duplication events that occurred independently within each algal lineage. Collectively, comparative genomic, physiological, and phylogenetic analyses of the C. variabilis NC64A hydrogenase has provided new insights into the molecular evolution and diversity of algal [FeFe]-hydrogenases.

  17. Enhancing hydrogen production of Enterobacter aerogenes by heterologous expression of hydrogenase genes originated from Synechocystis sp.

    PubMed

    Song, Wenlu; Cheng, Jun; Zhao, Jinfang; Zhang, Chuanxi; Zhou, Junhu; Cen, Kefa

    2016-09-01

    The hydrogenase genes (hoxEFUYH) of Synechocystis sp. PCC 6803 were cloned and heterologously expressed in Enterobacter aerogenes ATCC13408 for the first time in this study, and the hydrogen yield was significantly enhanced using the recombinant strain. A recombinant plasmid containing the gene in-frame with Glutathione-S-Transferase (GST) gene was transformed into E. aerogenes ATCC13408 to produce a GST-fusion protein. SDS-PAGE and western blot analysis confirm the successful expression of the hox genes. The hydrogenase activity of the recombinant strain is 237.6±9.3ml/(g-DW·h), which is 152% higher than the wild strain. The hydrogen yield of the recombinant strain is 298.3ml/g-glucose, which is 88% higher than the wild strain. During hydrogen fermentation, the recombinant strain produces more acetate and butyrate, but less ethanol. This is corresponding to the NADH metabolism in the cell due to the higher hydrogenase activity with the heterologous expression of hox genes. PMID:27343449

  18. Enhancing hydrogen production of Enterobacter aerogenes by heterologous expression of hydrogenase genes originated from Synechocystis sp.

    PubMed

    Song, Wenlu; Cheng, Jun; Zhao, Jinfang; Zhang, Chuanxi; Zhou, Junhu; Cen, Kefa

    2016-09-01

    The hydrogenase genes (hoxEFUYH) of Synechocystis sp. PCC 6803 were cloned and heterologously expressed in Enterobacter aerogenes ATCC13408 for the first time in this study, and the hydrogen yield was significantly enhanced using the recombinant strain. A recombinant plasmid containing the gene in-frame with Glutathione-S-Transferase (GST) gene was transformed into E. aerogenes ATCC13408 to produce a GST-fusion protein. SDS-PAGE and western blot analysis confirm the successful expression of the hox genes. The hydrogenase activity of the recombinant strain is 237.6±9.3ml/(g-DW·h), which is 152% higher than the wild strain. The hydrogen yield of the recombinant strain is 298.3ml/g-glucose, which is 88% higher than the wild strain. During hydrogen fermentation, the recombinant strain produces more acetate and butyrate, but less ethanol. This is corresponding to the NADH metabolism in the cell due to the higher hydrogenase activity with the heterologous expression of hox genes.

  19. Isolation of genes (nif/hup cosmids) involved in hydrogenase and nitrogenase activities in Rhizobium japonicum.

    PubMed

    Hom, S S; Graham, L A; Maier, R J

    1985-03-01

    Recombinant cosmids containing a Rhizobium japonicum gene involved in both hydrogenase (Hup) and nitrogenase (Nif) activities were isolated. An R. japonicum gene bank utilizing broad-host-range cosmid pLAFR1 was conjugated into Hup- Nif- R. japonicum strain SR139. Transconjugants containing the nif/hup cosmid were identified by their resistance to tetracycline (Tcr) and ability to grow chemoautotrophically (Aut+) with hydrogen. All Tcr Aut+ transconjugants possessed high levels of H2 uptake activity, as determined amperometrically. Moreover, all Hup+ transconjugants tested possessed the ability to reduce acetylene (Nif+) in soybean nodules. Cosmid DNAs from 19 Hup+ transconjugants were transferred to Escherichia coli by transformation. When the cosmids were restricted with EcoRI, 15 of the 19 cosmids had a restriction pattern with 13.2-, 4.0-, 3.0-, and 2.5-kilobase DNA fragments. Six E. coli transformants containing the nif/hup cosmids were conjugated with strain SR139. All strain SR139 transconjugants were Hup+ Nif+. Moreover, one nif/hup cosmid was transferred to 15 other R. japonicum Hup- mutants. Hup+ transconjugants of six of the Hup- mutants appeared at a frequency of 1.0, whereas the transconjugants of the other nine mutants remained Hup-. These results indicate that the nif/hup gene cosmids contain a gene involved in both nitrogenase and hydrogenase activities and at least one and perhaps other hup genes which are exclusively involved in H2 uptake activity.

  20. [FeFe]-hydrogenase-like gene is involved in the regulation of sensitivity to oxygen in yeast and nematode.

    PubMed

    Fujii, Michihiko; Adachi, Noritaka; Shikatani, Kazuki; Ayusawa, Dai

    2009-04-01

    Oxygen is essential for the life of aerobic organisms, but reactive oxygen species (ROS) derived from oxygen can be a threat for it. Many genes are involved in generation of ROS, but not much attention has been focused on the reactions from which ROS are generated. We therefore screened for mutants that showed an increased sensitivity to oxidative stress in the nematode Caenorhabditis elegans, and isolated a novel mutant, oxy-4(qa5001). This mutant showed an increased sensitivity to a high concentration of oxygen, and decreased longevity at 20 degrees C but not at 26 degrees C. The genetic analysis has revealed that oxy-4 had a causative mutation in an [FeFe]-hydrogenase-like gene (Y54H5A.4). In the yeast Saccharomyces cerevisiae, a deletion of NAR1, a possible homologue of oxy-4, also caused a similar increased sensitivity to oxygen. [FeFe]-hydrogenases are enzymes that catalyze both the formation and the splitting of molecular hydrogen, and function in anaerobic respiration in anaerobes. In contrast, [FeFe]-hydrogenase-like genes identified in aerobic eukaryotes do not generate hydrogen, and its functional roles are less understood. Our results suggested that [FeFe]-hydrogenase-like genes were involved in the regulation of sensitivity to oxygen in S. cerevisiae and C. elegans. PMID:19335616

  1. Cloning of hydrogenase genes and fine structure analysis of an operon essential for H2 metabolism in Escherichia coli.

    PubMed Central

    Sankar, P; Lee, J H; Shanmugam, K T

    1985-01-01

    Escherichia coli has two unlinked genes that code for hydrogenase synthesis and activity. The DNA fragments containing the two genes (hydA and hydB) were cloned into a plasmid vector, pBR322. The plasmids containing the hyd genes (pSE-290 and pSE-111 carrying the hydA and hydB genes, respectively) were used to genetically map a total of 51 mutant strains with defects in hydrogenase activity. A total of 37 mutants carried a mutation in the hydB gene, whereas the remaining 14 hyd were hydA. This complementation analysis also established the presence of two new genes, so far unidentified, one coding for formate dehydrogenase-2 (fdv) and another producing an electron transport protein (fhl) coupling formate dehydrogenase-2 to hydrogenase. Three of the four genes, hydB, fhl, and fdv, may constitute a single operon, and all three genes are carried by a 5.6-kilobase-pair chromosomal DNA insert in plasmid pSE-128. Plasmids carrying a part of this 5.6-kilobase-pair DNA (pSE-130) or fragments derived from this DNA in different orientations (pSE-126 and pSE-129) inhibited the production of active formate hydrogenlyase. This inhibition occurred even in a prototrophic E. coli, strain K-10, but only during an early induction period. These results, based on complementation analysis with cloned DNA fragments, show that both hydA and hydB genes are essential for the production of active hydrogenase. For the expression of active formate hydrogenlyase, two other gene products, fhl and fdv are also needed. All four genes map between 58 and 59 min in the E. coli chromosome. PMID:3884595

  2. The phylogeny of uptake hydrogenases in Frankia.

    PubMed

    Leul, Melakeselam; Normand, Philippe; Sellstedt, Anita

    2009-03-01

    Uptake hydrogenase is an enzyme that is beneficial for nitrogen fixation in bacteria. Recent studies have shown that Frankia sp. has two sets of uptake hydrogenase genes, organized in synton 1 and synton 2. In the present study, phylogenetic analysis of the structural subunits of hydrogenase syntons 1 and 2 showed a distinct clustering pattern between the proteins of Frankia strains that were isolated from different host plants and non-Frankia organisms. The structural subunits of hydrogenase synton 1 of Frankia sp. CpI1, Frankia alni ACN14a, and F. alni AvCI1 were grouped together while those of Frankia spp. CcI3, KB5, UGL140104, and UGL011102 formed another group. The structural subunits of hydrogenase synton 2 of F. alni ACN14a and Frankia spp. CcI3 and BCU110501 grouped together, but those of Frankia spp. KB5 and CpI1, F. alni ArI3, and F. alniAvCI1 comprised a separate group. The structural subunits of hydrogenase syntons 1 and 2 of Frankia sp. EAN1pec were more closely related to those of non-Frankia bacteria, i.e., Streptomyces avermitilis and Anaeromyxobacter sp., respectively, than to those of other Frankia strains, suggesting the occurrence of lateral gene transfer between these organisms. In addition, the accessory Hyp proteins of hydrogenase syntons 1 and 2 of F. alni ACN14a and Frankia sp. CcI3 were shown to be phylogenetically more related to each other than to those of Frankia EAN1pec. PMID:19440980

  3. Structural and gene expression analyses of uptake hydrogenases and other proteins involved in nitrogenase protection in Frankia.

    PubMed

    Richau, K H; Kudahettige, R L; Pujic, P; Kudahettige, N P; Sellstedt, A

    2013-11-01

    The actinorhizal bacterium Frankia expresses nitrogenase and can therefore convert molecular nitrogen into ammonia and the by-product hydrogen. However, nitrogenase is inhibited by oxygen. Consequently, Frankia and its actinorhizal hosts have developed various mechanisms for excluding oxygen from their nitrogen-containing compartments. These include the expression of oxygen-scavenging uptake hydrogenases, the formation of hopanoid-rich vesicles, enclosed by multi-layered hopanoid structures, the lignification of hyphal cell walls, and the production of haemoglobins in the symbiotic nodule. In this work, we analysed the expression and structure of the so-called uptake hydrogenase (Hup), which catalyses the in vivo dissociation of hydrogen to recycle the energy locked up in this 'waste' product. Two uptake hydrogenase syntons have been identified in Frankia: synton 1 is expressed under freeliving conditions while synton 2 is expressed during symbiosis. We used qPCR to determine synton 1 hup gene expression in two Frankia strains under aerobic and anaerobic conditions. We also predicted the 3D structures of the Hup protein subunits based on multiple sequence alignments and remote homology modelling. Finally, we performed BLAST searches of genome and protein databases to identify genes that may contribute to the protection of nitrogenase against oxygen in the two Frankia strains. Our results show that in Frankia strain ACN14a, the expression patterns of the large (HupL1) and small (HupS1) uptake hydrogenase subunits depend on the abundance of oxygen in the external environment. Structural models of the membrane-bound hydrogenase subunits of ACN14a showed that both subunits resemble the structures of known [NiFe] hydrogenases (Volbeda et al. 1995), but contain fewer cysteine residues than the uptake hydrogenase of the Frankia DC12 and Eu1c strains. Moreover, we show that all of the investigated Frankia strains have two squalene hopane cyclase genes (shc1 and shc2). The

  4. Deletion of a gene cluster for [Ni-Fe] hydrogenase maturation in the anaerobic hyperthermophilic bacterium Caldicellulosiruptor bescii identifies its role in hydrogen metabolism.

    PubMed

    Cha, Minseok; Chung, Daehwan; Westpheling, Janet

    2016-02-01

    The anaerobic, hyperthermophlic, cellulolytic bacterium Caldicellulosiruptor bescii grows optimally at ∼80 °C and effectively degrades plant biomass without conventional pretreatment. It utilizes a variety of carbohydrate carbon sources, including both C5 and C6 sugars, released from plant biomass and produces lactate, acetate, CO2, and H2 as primary fermentation products. The C. bescii genome encodes two hydrogenases, a bifurcating [Fe-Fe] hydrogenase and a [Ni-Fe] hydrogenase. The [Ni-Fe] hydrogenase is the most widely distributed in nature and is predicted to catalyze hydrogen production and to pump protons across the cellular membrane creating proton motive force. Hydrogenases are the key enzymes in hydrogen metabolism and their crystal structure reveals complexity in the organization of their prosthetic groups suggesting extensive maturation of the primary protein. Here, we report the deletion of a cluster of genes, hypABFCDE, required for maturation of the [Ni-Fe] hydrogenase. These proteins are specific for the hydrogenases they modify and are required for hydrogenase activity. The deletion strain grew more slowly than the wild type or the parent strain and produced slightly less hydrogen overall, but more hydrogen per mole of cellobiose. Acetate yield per mole of cellobiose was increased ∼67 % and ethanol yield per mole of cellobiose was decreased ∼39 %. These data suggest that the primary role of the [Ni-Fe] hydrogenase is to generate a proton gradient in the membrane driving ATP synthesis and is not the primary enzyme for hydrogen catalysis. In its absence, ATP is generated from increased acetate production resulting in more hydrogen produced per mole of cellobiose.

  5. RNA silencing of hydrogenase(-like) genes and investigation of their physiological roles in the green alga Chlamydomonas reinhardtii.

    PubMed

    Godman, James E; Molnár, Attila; Baulcombe, David C; Balk, Janneke

    2010-11-01

    The genome of the green alga Chlamydomonas reinhardtii encodes two [FeFe]-hydrogenases, HydA1 and HydA2, and the hydrogenase-like protein HYD3. The unique combination of these proteins in one eukaryotic cell allows for direct comparison of their in vivo functions, which have not been established for HydA2 and HYD3. Using an artificial microRNA silencing method developed recently, the expression of HydA1, HydA2 and HYD3 was specifically down-regulated. Silencing of HydA1 resulted in 4-fold lower hydrogenase protein and activity under anaerobic conditions. In contrast, silencing of HydA2 or HYD3 did not affect hydrogen production. Cell lines with strongly (>90%) decreased HYD3 transcript levels grew more slowly than wild-type. The activity of aldehyde oxidase, a cytosolic Fe-S enzyme, was decreased in HYD3-knockdown lines, whereas Fe-S dependent activities in the chloroplast and mitochondria were unaffected. In addition, the HYD3-knockdown lines grew poorly on hypoxanthine, indicating impaired function of xanthine dehydrogenase, another cytosolic Fe-S enzyme. The expression levels of selected genes in response to hypoxia were unaltered upon HYD3 silencing. Together, our results clearly distinguish the cellular roles of HydA1 and HYD3, and indicate that HYD3, like its yeast and human homologues, has an evolutionary conserved role in the biogenesis or maintenance of cytosolic Fe-S proteins.

  6. Genetic diversity of Desulfovibrio spp. in environmental samples analyzed by denaturing gradient gel electrophoresis of [NiFe] hydrogenase gene fragments.

    PubMed Central

    Wawer, C; Muyzer, G

    1995-01-01

    The genetic diversity of Desulfovibrio species in environmental samples was determined by denaturing gradient gel electrophoresis (DGGE) of PCR-amplified [NiFe] hydrogenase gene fragments. Five different PCR primers were designed after comparative analysis of [NiFe] hydrogenase gene sequences from three Desulfovibrio species. These primers were tested in different combinations on the genomic DNAs of a variety of hydrogenase-containing and hydrogenase-lacking bacteria. One primer pair was found to be specific for Desulfovibrio species only, while the others gave positive results with other bacteria also. By using this specific primer pair, we were able to amplify the [NiFe] hydrogenase genes of DNAs isolated from environmental samples and to detect the presence of Desulfovibrio species in these samples. However, only after DGGE analysis of these PCR products could the number of different Desulfovibrio species within the samples be determined. DGGE analysis of PCR products from different bioreactors demonstrated up to two bands, while at least five distinguishable bands were detected in a microbial mat sample. Because these bands most likely represent as many Desulfovibrio species present in these samples, we conclude that the genetic diversity of Desulfovibrio species in the natural microbial mat is far greater than that in the experimental bioreactors. PMID:7793940

  7. Reactions of [FeFe]-hydrogenase models involving the formation of hydrides related to proton reduction and hydrogen oxidation.

    PubMed

    Wang, Ning; Wang, Mei; Chen, Lin; Sun, Licheng

    2013-09-14

    [FeFe]-hydrogenases are enzymes in nature that catalyze the reduction of protons and the oxidation of H2 at neutral pH with remarkably high activities and incredibly low overpotential. Structural and functional biomimicking of the active site of [FeFe]-hydrogenases can provide helpful hints for elucidating the mechanism of H2 evolution and uptake at the [FeFe]-hydrogenase active site and for designing bioinspired catalysts to replace the expensive noble metal catalysts for H2 generation and uptake. This perspective focuses on the recent progress in the formation and reactivity of iron hydrides closely related to the processes of proton reduction and hydrogen oxidation mediated by diiron dithiolate complexes. The second section surveys the bridging and terminal hydride species formed from various diiron complexes as well as the intramolecular proton transfer. The very recent progress in H2 activation by diiron dithiolate models are reviewed in the third section. In the concluding remarks and outlook, the differences in structure and catalytic mechanism between the synthetic models and the native [FeFe]-H2ase active site are compared and analyzed, which may cause the need for a significantly larger driving force and may lead to lower activities of synthetic models than the [FeFe]-H2ases for H2 generation and uptake.

  8. Diiron dithiolato carbonyls related to the H(ox)CO state of [FeFe]-hydrogenase.

    PubMed

    Justice, Aaron K; Nilges, Mark J; Rauchfuss, Thomas B; Wilson, Scott R; De Gioia, Luca; Zampella, Giuseppe

    2008-04-16

    Oxidation of the electron-rich (E(1/2) = -175 vs Ag/AgCl) ethanedithiolato complex Fe2(S2C2H4)(CO)2(dppv)2 (1) under a CO atmosphere yielded [Fe2(S2C2H4)(mu-CO)(CO)2(dppv)2](+) ([1(CO)](+)), a model for the H(ox)(CO) state of the [FeFe]-hydrogenases. This complex exists as two isomers: a kinetically favored unsymmetrical derivative, unsym-[1(CO)](+), and a thermodynamically favored isomer, sym-[1(CO)](+), wherein both diphosphines span apical and basal sites. Crystallographic characterization of sym-[1(CO)](+) confirmed a C2-symmetric structure with a bridging CO ligand and an elongated Fe-Fe bond of 2.7012(14) A, as predicted previously. Oxidation of sym-[1(CO)](+) and unsym-[1(CO)](+) again by 1e(-) oxidation afforded the respective diamagnetic diferrous derivatives where the relative stabilities of the sym and unsym isomers are reversed. DFT calculations indicate that the stabilities of sym and unsym isomers are affected differently by the oxidation state of the diiron unit: the mutually trans CO ligands in the sym isomer are more destabilizing in the mixed-valence state than in the diferrous state. EPR analysis of mixed-valence complexes revealed that, for [1](+), the unpaired spin is localized on a single iron center, whereas for unsym/sym-[1(CO)](+), the unpaired spin was delocalized over both iron centers, as indicated by the magnitude of the hyperfine coupling to the phosphine ligands trans to the Fe-Fe vector. Oxidation of 1 by 2 equiv of acetylferrocenium afforded the dication [1](2+), which, on the basis of low-temperature IR spectrum, is structurally similar to [1](+). Treatment of [1](2+) with CO gives unsym-[1(CO)](2+).

  9. Diiron Dithiolato Carbonyls Related to the HoxCO State of [FeFe]-Hydrogenase

    PubMed Central

    Justice, Aaron K.; Nilges, Mark J.; Rauchfuss, Thomas B.; Wilson, Scott R.; De Gioia, Luca; Zampella, Giuseppe

    2008-01-01

    Oxidation of the electron-rich (E1/2 = −175 vs Ag/AgCl) ethanedithiolato complex Fe2(S2C2H4)-(CO)2(dppv)2 (1) under a CO atmosphere yielded [Fe2(S2C2H4)(μ-CO)(CO)2(dppv)2]+ ([1(CO)]+), a model for the HoxCO state of the [FeFe]-hydrogenases. This complex exists as two isomers: a kinetically favored unsymmetrical derivative, unsym-[1(CO)]+, and a thermodynamically favored isomer, sym-[1(CO)]+, wherein both diphosphines span apical and basal sites. Crystallographic characterization of sym-[1(CO)]+ confirmed a C2-symmetric structure with a bridging CO ligand and an elongated Fe–Fe bond of 2.7012(14) Å, as predicted previously. Oxidation of sym-[1(CO)]+ and unsym-[1(CO)]+ again by 1e− oxidation afforded the respective diamagnetic diferrous derivatives where the relative stabilities of the sym and unsym isomers are reversed. DFT calculations indicate that the stabilities of sym and unsym isomers are affected differently by the oxidation state of the diiron unit: the mutually trans CO ligands in the sym isomer are more destabilizing in the mixed-valence state than in the diferrous state. EPR analysis of mixed-valence complexes revealed that, for [1]+, the unpaired spin is localized on a single iron center, whereas for unsym/sym-[1(CO)]+, the unpaired spin was delocalized over both iron centers, as indicated by the magnitude of the hyperfine coupling to the phosphine ligands trans to the Fe–Fe vector. Oxidation of 1 by 2 equiv of acetylferrocenium afforded the dication [1]2+, which, on the basis of low-temperature IR spectrum, is structurally similar to [1]+. Treatment of [1]2+ with CO gives unsym-[1(CO)]2+. PMID:18341276

  10. H2-Producing Bacterial Community during Rice Straw Decomposition in Paddy Field Soil: Estimation by an Analysis of [FeFe]-Hydrogenase Gene Transcripts

    PubMed Central

    Baba, Ryuko; Asakawa, Susumu; Watanabe, Takeshi

    2016-01-01

    The transcription patterns of [FeFe]-hydrogenase genes (hydA), which encode the enzymes responsible for H2 production, were investigated during rice straw decomposition in paddy soil using molecular biological techniques. Paddy soil amended with and without rice straw was incubated under anoxic conditions. RNA was extracted from the soil, and three clone libraries of hydA were constructed using RNAs obtained from samples in the initial phase of rice straw decomposition (day 1 with rice straw), methanogenic phase of rice straw decomposition (day 14 with rice straw), and under a non-amended condition (day 14 without rice straw). hydA genes related to Proteobacteria, Firmicutes, Bacteroidetes, Chloroflexi, and Thermotogae were mainly transcribed in paddy soil samples; however, their proportions markedly differed among the libraries. Deltaproteobacteria-related hydA genes were predominantly transcribed on day 1 with rice straw, while various types of hydA genes related to several phyla were transcribed on day 14 with rice straw. Although the diversity of transcribed hydA was significantly higher in the library on day 14 with rice straw than the other two libraries, the composition of hydA transcripts in the library was similar to that in the library on day 14 without rice straw. These results indicate that the composition of active H2 producers and/or H2 metabolic patterns dynamically change during rice straw decomposition in paddy soil. PMID:27319579

  11. H2-Producing Bacterial Community during Rice Straw Decomposition in Paddy Field Soil: Estimation by an Analysis of [FeFe]-Hydrogenase Gene Transcripts.

    PubMed

    Baba, Ryuko; Asakawa, Susumu; Watanabe, Takeshi

    2016-09-29

    The transcription patterns of [FeFe]-hydrogenase genes (hydA), which encode the enzymes responsible for H2 production, were investigated during rice straw decomposition in paddy soil using molecular biological techniques. Paddy soil amended with and without rice straw was incubated under anoxic conditions. RNA was extracted from the soil, and three clone libraries of hydA were constructed using RNAs obtained from samples in the initial phase of rice straw decomposition (day 1 with rice straw), methanogenic phase of rice straw decomposition (day 14 with rice straw), and under a non-amended condition (day 14 without rice straw). hydA genes related to Proteobacteria, Firmicutes, Bacteroidetes, Chloroflexi, and Thermotogae were mainly transcribed in paddy soil samples; however, their proportions markedly differed among the libraries. Deltaproteobacteria-related hydA genes were predominantly transcribed on day 1 with rice straw, while various types of hydA genes related to several phyla were transcribed on day 14 with rice straw. Although the diversity of transcribed hydA was significantly higher in the library on day 14 with rice straw than the other two libraries, the composition of hydA transcripts in the library was similar to that in the library on day 14 without rice straw. These results indicate that the composition of active H2 producers and/or H2 metabolic patterns dynamically change during rice straw decomposition in paddy soil.

  12. H2-Producing Bacterial Community during Rice Straw Decomposition in Paddy Field Soil: Estimation by an Analysis of [FeFe]-Hydrogenase Gene Transcripts.

    PubMed

    Baba, Ryuko; Asakawa, Susumu; Watanabe, Takeshi

    2016-09-29

    The transcription patterns of [FeFe]-hydrogenase genes (hydA), which encode the enzymes responsible for H2 production, were investigated during rice straw decomposition in paddy soil using molecular biological techniques. Paddy soil amended with and without rice straw was incubated under anoxic conditions. RNA was extracted from the soil, and three clone libraries of hydA were constructed using RNAs obtained from samples in the initial phase of rice straw decomposition (day 1 with rice straw), methanogenic phase of rice straw decomposition (day 14 with rice straw), and under a non-amended condition (day 14 without rice straw). hydA genes related to Proteobacteria, Firmicutes, Bacteroidetes, Chloroflexi, and Thermotogae were mainly transcribed in paddy soil samples; however, their proportions markedly differed among the libraries. Deltaproteobacteria-related hydA genes were predominantly transcribed on day 1 with rice straw, while various types of hydA genes related to several phyla were transcribed on day 14 with rice straw. Although the diversity of transcribed hydA was significantly higher in the library on day 14 with rice straw than the other two libraries, the composition of hydA transcripts in the library was similar to that in the library on day 14 without rice straw. These results indicate that the composition of active H2 producers and/or H2 metabolic patterns dynamically change during rice straw decomposition in paddy soil. PMID:27319579

  13. Fundamental Studies of Recombinant Hydrogenases

    SciTech Connect

    Adams, Michael W

    2014-01-25

    This research addressed the long term goals of understanding the assembly and organization of hydrogenase enzymes, of reducing them in size and complexity, of determining structure/function relationships, including energy conservation via charge separation across membranes, and in screening for novel H2 catalysts. A key overall goal of the proposed research was to define and characterize minimal hydrogenases that are produced in high yields and are oxygen-resistant. Remarkably, in spite of decades of research carried out on hydrogenases, it is not possible to readily manipulate or design the enzyme using molecular biology approaches since a recombinant form produced in a suitable host is not available. Such resources are essential if we are to understand what constitutes a “minimal” hydrogenase and design such catalysts with certain properties, such as resistance to oxygen, extreme stability and specificity for a given electron donor. The model system for our studies is Pyrococcus furiosus, a hyperthermophile that grows optimally at 100°C, which contains three different nickel-iron [NiFe-] containing hydrogenases. Hydrogenases I and II are cytoplasmic while the other, MBH, is an integral membrane protein that functions to both evolve H2 and pump protons. Three important breakthroughs were made during the funding period with P. furiosus soluble hydrogenase I (SHI). First, we produced an active recombinant form of SHI in E. coli by the co-expression of sixteen genes using anaerobically-induced promoters. Second, we genetically-engineered P. furiosus to overexpress SHI by an order of magnitude compared to the wild type strain. Third, we generated the first ‘minimal’ form of SHI, one that contained two rather than four subunits. This dimeric form was stable and active, and directly interacted with a pyruvate-oxidizing enzyme with any intermediate electron carrier. The research resulted in five peer-reviewed publications.

  14. Hydrogen evolution in [NiFe] hydrogenases and related biomimetic systems: similarities and differences.

    PubMed

    Das, Ranjita; Neese, Frank; van Gastel, Maurice

    2016-09-21

    In this work, a detailed quantum chemical study of the mechanism of [Ni(bdt)(dppf)] (Ni(II)L) catalyzed hydrogen formation [A. Gan, T. L. Groy, P. Tarakeshwar, S. K. S. Mazinani, J. Shearer, V. Mujica and A. K. Jones, J. Am. Chem. Soc., 2015, 137, 1109-1115] following an electro-chemical-electro-chemical (ECEC) pathway is reported. The complex exclusively catalyzes the reduction of protons to molecular hydrogen. The calculations suggest that the first one-electron reduction of the [Ni(II)L] catalyst is the rate limiting step of the catalytic cycle and hence, the buildup of detectable reaction intermediates is not expected. The catalytic activity of the [Ni(II)L] complex is facilitated by the flexibility of the ligand system, which allows the ligand framework to adapt to changes in the Ni oxidation state over the course of the reaction. Additionally, a comparison is made with the catalytic activity of [NiFe] hydrogenase. It is argued that the directionality of the reversible hydrogen formation reaction is controlled by the ligand field of the nickel ion and the possibility for side-on (η(2)) binding of H2: if the ligand framework does not allow for η(2) binding of H2, as is the case for [Ni(II)L], the catalyst irreversibly reduces protons. If the ligand field allows η(2) binding of H2, the catalyst can in principle work reversibly. The conditions for η(2) binding are discussed. PMID:27545687

  15. Relation between anaerobic inactivation and oxygen tolerance in a large series of NiFe hydrogenase mutants

    PubMed Central

    Abou Hamdan, Abbas; Liebgott, Pierre-Pol; Fourmond, Vincent; Gutiérrez-Sanz, Oscar; De Lacey, Antonio L.; Infossi, Pascale; Rousset, Marc; Dementin, Sébastien; Léger, Christophe

    2012-01-01

    Nickel-containing hydrogenases, the biological catalysts of oxidation and production, reversibly inactivate under anaerobic, oxidizing conditions. We aim at understanding the mechanism of (in)activation and what determines its kinetics, because there is a correlation between fast reductive reactivation and oxygen tolerance, a property of some hydrogenases that is very desirable from the point of view of biotechnology. Direct electrochemistry is potentially very useful for learning about the redox-dependent conversions between active and inactive forms of hydrogenase, but the voltammetric signals are complex and often misread. Here we describe simple analytical models that we used to characterize and compare 16 mutants, obtained by substituting the position-74 valine of the -sensitive NiFe hydrogenase from Desulfovibrio fructosovorans. We observed that this substitution can accelerate reactivation up to 1,000-fold, depending on the polarity of the position 74 amino acid side chain. In terms of kinetics of anaerobic (in)activation and oxygen tolerance, the valine-to-histidine mutation has the most spectacular effect: The V74H mutant compares favorably with the -tolerant hydrogenase from Aquifex aeolicus, which we use here as a benchmark. PMID:23169623

  16. Relation between anaerobic inactivation and oxygen tolerance in a large series of NiFe hydrogenase mutants.

    PubMed

    Abou Hamdan, Abbas; Liebgott, Pierre-Pol; Fourmond, Vincent; Gutiérrez-Sanz, Oscar; De Lacey, Antonio L; Infossi, Pascale; Rousset, Marc; Dementin, Sébastien; Léger, Christophe

    2012-12-01

    Nickel-containing hydrogenases, the biological catalysts of oxidation and production, reversibly inactivate under anaerobic, oxidizing conditions. We aim at understanding the mechanism of (in)activation and what determines its kinetics, because there is a correlation between fast reductive reactivation and oxygen tolerance, a property of some hydrogenases that is very desirable from the point of view of biotechnology. Direct electrochemistry is potentially very useful for learning about the redox-dependent conversions between active and inactive forms of hydrogenase, but the voltammetric signals are complex and often misread. Here we describe simple analytical models that we used to characterize and compare 16 mutants, obtained by substituting the position-74 valine of the -sensitive NiFe hydrogenase from Desulfovibrio fructosovorans. We observed that this substitution can accelerate reactivation up to 1,000-fold, depending on the polarity of the position 74 amino acid side chain. In terms of kinetics of anaerobic (in)activation and oxygen tolerance, the valine-to-histidine mutation has the most spectacular effect: The V74H mutant compares favorably with the -tolerant hydrogenase from Aquifex aeolicus, which we use here as a benchmark. PMID:23169623

  17. Differential Expression of the Chlamydomonas [FeFe]-Hydrogenase-Encoding HYDA1 Gene Is Regulated by the COPPER RESPONSE REGULATOR11[C][W

    PubMed Central

    Pape, Miriam; Lambertz, Camilla; Happe, Thomas; Hemschemeier, Anja

    2012-01-01

    The unicellular green alga Chlamydomonas reinhardtii adapts to anaerobic or hypoxic conditions by developing a complex fermentative metabolism including the production of molecular hydrogen by [FeFe]-hydrogenase isoform1 (HYDA1). HYDA1 transcript and hydrogenase protein accumulate in the absence of oxygen or copper (Cu). Factors regulating this differential gene expression have been unknown so far. In this study, we report on the isolation of a Chlamydomonas mutant strain impaired in HYDA1 gene expression by screening an insertional mutagenesis library for HYDA1 promoter activity using the arylsulfatase-encoding ARYLSULFATASE2 gene as a selection marker. The mutant strain has a deletion of the COPPER RESPONSE REGULATOR1 (CRR1) gene encoding for CRR1, indicating that this SQUAMOSA-PROMOTER BINDING PROTEIN (SBP) domain transcription factor is involved in the regulation of HYDA1 transcription. Treating the C. reinhardtii wild type with mercuric ions, which were shown to inhibit the binding of the SBP domain to DNA, prevented or deactivated HYDA1 gene expression. Reporter gene analyses of the HYDA1 promoter revealed that two GTAC motifs, which are known to be the cores of CRR1 binding sites, are necessary for full promoter activity in hypoxic conditions or upon Cu starvation. However, mutations of the GTAC sites had a much stronger impact on reporter gene expression in Cu-deficient cells. Electrophoretic mobility shift assays showed that the CRR1 SBP domain binds to one of the GTAC cores in vitro. These combined results prove that CRR1 is involved in HYDA1 promoter activation. PMID:22669892

  18. Transcriptional regulation of genes encoding the selenium-free [NiFe]-hydrogenases in the archaeon Methanococcus voltae involves positive and negative control elements.

    PubMed Central

    Noll, I; Müller, S; Klein, A

    1999-01-01

    Methanococcus voltae harbors genetic information for two pairs of homologous [NiFe]-hydrogenases. Two of the enzymes contain selenocysteine, while the other two gene groups encode apparent isoenzymes that carry cysteinyl residues in the homologous positions. The genes coding for the selenium-free enzymes, frc and vhc, are expressed only under selenium limitation. They are transcribed out of a common intergenic region. A series of deletions made in the intergenic region localized a common negative regulatory element for the vhc and frc promoters as well as two activator elements that are specific for each of the two transcription units. Repeated sequences, partially overlapping the frc promoter, were also detected. Mutations in these repeated heptanucleotide sequences led to a weak induction of a reporter gene under the control of the frc promoters in the presence of selenium. This result suggests that the heptamer repeats contribute to the negative regulation of the frc transcription unit. PMID:10430564

  19. Anaerobic acclimation in Chlamydomonas reinhardtii: anoxic gene expression, hydrogenase induction, and metabolic pathways.

    PubMed

    Mus, Florence; Dubini, Alexandra; Seibert, Michael; Posewitz, Matthew C; Grossman, Arthur R

    2007-08-31

    Both prokaryotic and eukaryotic photosynthetic microbes experience conditions of anoxia, especially during the night when photosynthetic activity ceases. In Chlamydomonas reinhardtii, dark anoxia is characterized by the activation of an extensive set of fermentation pathways that act in concert to provide cellular energy, while limiting the accumulation of potentially toxic fermentative products. Metabolite analyses, quantitative PCR, and high density Chlamydomonas DNA microarrays were used to monitor changes in metabolite accumulation and gene expression during acclimation of the cells to anoxia. Elevated levels of transcripts encoding proteins associated with the production of H2, organic acids, and ethanol were observed in congruence with the accumulation of fermentation products. The levels of over 500 transcripts increased significantly during acclimation of the cells to anoxic conditions. Among these were transcripts encoding transcription/translation regulators, prolyl hydroxylases, hybrid cluster proteins, proteases, transhydrogenase, catalase, and several putative proteins of unknown function. Overall, this study uses metabolite, genomic, and transcriptome data to provide genome-wide insights into the regulation of the complex metabolic networks utilized by Chlamydomonas under the anaerobic conditions associated with H2 production. PMID:17565990

  20. Rubredoxin-related Maturation Factor Guarantees Metal Cofactor Integrity during Aerobic Biosynthesis of Membrane-bound [NiFe] Hydrogenase*

    PubMed Central

    Fritsch, Johannes; Siebert, Elisabeth; Priebe, Jacqueline; Zebger, Ingo; Lendzian, Friedhelm; Teutloff, Christian; Friedrich, Bärbel; Lenz, Oliver

    2014-01-01

    The membrane-bound [NiFe] hydrogenase (MBH) supports growth of Ralstonia eutropha H16 with H2 as the sole energy source. The enzyme undergoes a complex biosynthesis process that proceeds during cell growth even at ambient O2 levels and involves 14 specific maturation proteins. One of these is a rubredoxin-like protein, which is essential for biosynthesis of active MBH at high oxygen concentrations but dispensable under microaerobic growth conditions. To obtain insights into the function of HoxR, we investigated the MBH protein purified from the cytoplasmic membrane of hoxR mutant cells. Compared with wild-type MBH, the mutant enzyme displayed severely decreased hydrogenase activity. Electron paramagnetic resonance and infrared spectroscopic analyses revealed features resembling those of O2-sensitive [NiFe] hydrogenases and/or oxidatively damaged protein. The catalytic center resided partially in an inactive Niu-A-like state, and the electron transfer chain consisting of three different Fe-S clusters showed marked alterations compared with wild-type enzyme. Purification of HoxR protein from its original host, R. eutropha, revealed only low protein amounts. Therefore, recombinant HoxR protein was isolated from Escherichia coli. Unlike common rubredoxins, the HoxR protein was colorless, rather unstable, and essentially metal-free. Conversion of the atypical iron-binding motif into a canonical one through genetic engineering led to a stable reddish rubredoxin. Remarkably, the modified HoxR protein did not support MBH-dependent growth at high O2. Analysis of MBH-associated protein complexes points toward a specific interaction of HoxR with the Fe-S cluster-bearing small subunit. This supports the previously made notion that HoxR avoids oxidative damage of the metal centers of the MBH, in particular the unprecedented Cys6[4Fe-3S] cluster. PMID:24448806

  1. Application to Photocatalytic H2 Production of a Whole-Cell Reaction by Recombinant Escherichia coli Cells Expressing [FeFe]-Hydrogenase and Maturases Genes.

    PubMed

    Honda, Yuki; Hagiwara, Hidehisa; Ida, Shintaro; Ishihara, Tatsumi

    2016-07-01

    A photocatalytic H2 production system using an inorganic-bio hybrid photocatalyst could contribute to the efficient utilization of solar energy, but would require the development of a new approach for preparing a H2 -forming biocatalyst. In the present study, we constructed a recombinant strain of Escherichia coli expressing the genes encoding the [FeFe]-hydrogenase and relevant maturases from Clostridium acetobutylicum NBRC 13948 for use as a biocatalyst. We investigated the direct application of a whole-cell of the recombinant E. coli. The combination of TiO2 , methylviologen, and the recombinant E. coli formed H2 under light irradiation, demonstrating that whole cells of the recombinant E. coli could be employed for photocatalytic H2 production without any time-consuming and costly manipulations (for example, enzyme purification). This is the first report of the direct application of a whole-cell reaction of recombinant E. coli to photocatalytic H2 production. PMID:27194524

  2. Regulation and genetic organization of hydrogenase: Progress report, 1 June 1985--31 March 1986

    SciTech Connect

    Krasna, A.I.

    1989-01-01

    The experiments concentrate on development of screening methods and cloning of the hydrogenase gene. The first method used to distinguish between hydrogenase-negative and hydrogenase-positive cells of E. coli is to measure the ability of colonies of the cells on agar plates (with complex or minimal media with or without antibiotics) to reduce the dye methyl viologen with H/sub 2/ gas. The presence of hydrogenase activity in the positive colonies is confirmed by growth in liquid media. 3 figs., 2 tabs.

  3. Flexibility in Anaerobic Metabolism as Revealed in a Mutant of Chlamydomonas reinhardtii Lacking Hydrogenase Activity

    SciTech Connect

    Dubini, A.; Mus, F.; Seibert, M.; Grossman, A. R.; Posewitz, M. C.

    2009-03-13

    The green alga Chlamydomonas reinhardtii has a network of fermentation pathways that become active when cells acclimate to anoxia. Hydrogenase activity is an important component of this metabolism, and we have compared metabolic and regulatory responses that accompany anaerobiosis in wild-type C. reinhardtii cells and a null mutant strain for the HYDEF gene (hydEF-1 mutant), which encodes an [FeFe] hydrogenase maturation protein. This mutant has no hydrogenase activity and exhibits elevated accumulation of succinate and diminished production of CO2 relative to the parental strain during dark, anaerobic metabolism. In the absence of hydrogenase activity, increased succinate accumulation suggests that the cells activate alternative pathways for pyruvate metabolism, which contribute to NAD(P)H reoxidation, and continued glycolysis and fermentation in the absence of O2. Fermentative succinate production potentially proceeds via the formation of malate, and increases in the abundance of mRNAs encoding two malateforming enzymes, pyruvate carboxylase and malic enzyme, are observed in the mutant relative to the parental strain following transfer of cells from oxic to anoxic conditions. Although C. reinhardtii has a single gene encoding pyruvate carboxylase, it has six genes encoding putative malic enzymes. Only one of the malic enzyme genes, MME4, shows a dramatic increase in expression (mRNA abundance) in the hydEF-1 mutant during anaerobiosis. Furthermore, there are marked increases in transcripts encoding fumarase and fumarate reductase, enzymes putatively required to convert malate to succinate. These results illustrate the marked metabolic flexibility of C. reinhardtii and contribute to the development of an informed model of anaerobic metabolism in this and potentially other algae.

  4. Distribution Analysis of Hydrogenases in Surface Waters of Marine and Freshwater Environments

    PubMed Central

    Barz, Martin; Beimgraben, Christian; Staller, Torsten; Germer, Frauke; Opitz, Friederike; Marquardt, Claudia; Schwarz, Christoph; Gutekunst, Kirstin; Vanselow, Klaus Heinrich; Schmitz, Ruth; LaRoche, Julie; Schulz, Rüdiger; Appel, Jens

    2010-01-01

    Background Surface waters of aquatic environments have been shown to both evolve and consume hydrogen and the ocean is estimated to be the principal natural source. In some marine habitats, H2 evolution and uptake are clearly due to biological activity, while contributions of abiotic sources must be considered in others. Until now the only known biological process involved in H2 metabolism in marine environments is nitrogen fixation. Principal Findings We analyzed marine and freshwater environments for the presence and distribution of genes of all known hydrogenases, the enzymes involved in biological hydrogen turnover. The total genomes and the available marine metagenome datasets were searched for hydrogenase sequences. Furthermore, we isolated DNA from samples from the North Atlantic, Mediterranean Sea, North Sea, Baltic Sea, and two fresh water lakes and amplified and sequenced part of the gene encoding the bidirectional NAD(P)-linked hydrogenase. In 21% of all marine heterotrophic bacterial genomes from surface waters, one or several hydrogenase genes were found, with the membrane-bound H2 uptake hydrogenase being the most widespread. A clear bias of hydrogenases to environments with terrestrial influence was found. This is exemplified by the cyanobacterial bidirectional NAD(P)-linked hydrogenase that was found in freshwater and coastal areas but not in the open ocean. Significance This study shows that hydrogenases are surprisingly abundant in marine environments. Due to its ecological distribution the primary function of the bidirectional NAD(P)-linked hydrogenase seems to be fermentative hydrogen evolution. Moreover, our data suggests that marine surface waters could be an interesting source of oxygen-resistant uptake hydrogenases. The respective genes occur in coastal as well as open ocean habitats and we presume that they are used as additional energy scavenging devices in otherwise nutrient limited environments. The membrane-bound H2-evolving

  5. Hydrogenases and Hydrogen Metabolism of Cyanobacteria

    PubMed Central

    Tamagnini, Paula; Axelsson, Rikard; Lindberg, Pia; Oxelfelt, Fredrik; Wünschiers, Röbbe; Lindblad, Peter

    2002-01-01

    Cyanobacteria may possess several enzymes that are directly involved in dihydrogen metabolism: nitrogenase(s) catalyzing the production of hydrogen concomitantly with the reduction of dinitrogen to ammonia, an uptake hydrogenase (encoded by hupSL) catalyzing the consumption of hydrogen produced by the nitrogenase, and a bidirectional hydrogenase (encoded by hoxFUYH) which has the capacity to both take up and produce hydrogen. This review summarizes our knowledge about cyanobacterial hydrogenases, focusing on recent progress since the first molecular information was published in 1995. It presents the molecular knowledge about cyanobacterial hupSL and hoxFUYH, their corresponding gene products, and their accessory genes before finishing with an applied aspect—the use of cyanobacteria in a biological, renewable production of the future energy carrier molecular hydrogen. In addition to scientific publications, information from three cyanobacterial genomes, the unicellular Synechocystis strain PCC 6803 and the filamentous heterocystous Anabaena strain PCC 7120 and Nostoc punctiforme (PCC 73102/ATCC 29133) is included. PMID:11875125

  6. Enhancement of photoheterotrophic biohydrogen production at elevated temperatures by the expression of a thermophilic clostridial hydrogenase.

    PubMed

    Lo, Shou-Chen; Shih, Shau-Hua; Chang, Jui-Jen; Wang, Chun-Ying; Huang, Chieh-Chen

    2012-08-01

    The working temperature of a photobioreactor under sunlight can be elevated above the optimal growth temperature of a microorganism. To improve the biohydrogen productivity of photosynthetic bacteria at higher temperatures, a [FeFe]-hydrogenase gene from the thermophile Clostridium thermocellum was expressed in the mesophile Rhodopseudomonas palustris CGA009 (strain CGA-CThydA) using a log-phase expression promoter P( pckA ) to drive the expression of heterogeneous hydrogenase gene. In contrast, a mesophilic Clostridium acetobutylicum [FeFe]-hydrogenase gene was also constructed and expressed in R. palustris (strain CGA-CAhydA). Both transgenic strains were tested for cell growth, in vivo hydrogen production rate, and in vitro hydrogenase activity at elevated temperatures. Although both CGA-CThydA and CGA-CAhydA strains demonstrated enhanced growth over the vector control at temperatures above 38 °C, CGA-CThydA produced more hydrogen than the other strains. The in vitro hydrogenase activity assay, measured at 40 °C, confirmed that the activity of the CGA-CThydA hydrogenase was higher than the CGA-CAhydA hydrogenase. These results showed that the expression of a thermophilic [FeFe]-hydrogenase in R. palustris increased the growth rate and biohydrogen production at elevated temperatures. This transgenic strategy can be applied to a broad range of purple photosynthetic bacteria used to produce biohydrogen under sunlight.

  7. Role of nickel in membrane-bound hydrogenase and nickel metabolism in Rhizobium japonicum

    SciTech Connect

    Stults, L.W.

    1986-01-01

    The membrane-bound hydrogenase of Rhizobium japonicum requires nickel for activity. Radioactive /sup 63/Ni co-migrates with hydrogenase activity in native gel systems and co-elutes with purified hydrogenase form an affinity matrix column. A simplified scheme for the purification of hydrogenase has been developed and constitutes the first report of the aerobic purification of this enzyme from R. japonicum. The aerobic purification utilizes the general affinity matrix. Reactive Red 120-agarose and results in higher specific activity and yield of enzyme than previously reported. The stability of aerobically purified hydrogenase to oxygen is substantially greater than that reported for anaerobically isolated enzyme. Reduction of the aerobically purified enzyme in the presence of oxygen, however, results in the rapid loss of activity. R. japonicum cells accumulate nickel during heterotrophic growth and as non-growing cells. The hydrogenase constitutive mutant SR470 accumulates substantially greater amounts of nickel under both conditions. Kinetic studies indicate that the nickel uptake system in the hydrogenase constitutive mutant SR470 is upregulated relative to SRwt cells. The uptake system is specific for nickel, although a 10-fold excess (relative to nickel) of copper or zinc inhibits nickel uptake. The nickel uptake system appears to require energy. Under nickel-free conditions hydrogenase protein is not synthesized as determined by cross-reactivity with antibodies directed against hydrogenase, indicating that nickel regulates the formation of the enzyme as well as being a constituent of the active protein.

  8. Elimination of hydrogenase active site assembly blocks H2 production and increases ethanol yield in Clostridium thermocellum

    SciTech Connect

    Biswas, Ranjita; Zheng, Tianyong; Olson, Daniel G.; Lynd, Lee R.; Guss, Adam M.

    2015-02-01

    The native ability of Clostridium thermocellum to rapidly consume cellulose and produce ethanol makes it a leading candidate for a consolidated bioprocessing (CBP) biofuel production strategy. C. thermocellum also synthesizes lactate, formate, acetate, H2, and amino acids that compete with ethanol production for carbon and electrons. Elimination of H2 production could redirect carbon flux towards ethanol production by making more electrons available for acetyl-CoA reduction to ethanol. C. thermocellum encodes four hydrogenases and rather than delete each individually, we targeted a hydrogenase maturase gene (hydG), involved in converting the three [FeFe] hydrogenase apoenzymes into holoenzymes. Further deletion of the [NiFe] hydrogenase (ech) resulted in a mutant that functionally lacks all four hydrogenases. H2 production in hydG ech was undetectable and ethanol yield increased nearly 2-fold compared to wild type. Interestingly, mutant growth improved upon the addition of acetate, which led to increased expression of genes related to sulfate metabolism, suggesting these mutants may use sulfate as a terminal electron acceptor to balance redox reactions. Genomic analysis of hydG revealed a mutation in adhE, resulting in a strain with both NADH- and NADPH-dependent alcohol dehydrogenase activities. While this same adhE mutation is found in ethanol tolerant C. thermocellum strain E50C, hydG and hydG ech are not more ethanol tolerant than wild type, illustrating the complicated interactions between redox balancing and ethanol tolerance in C. thermocellum. The dramatic increase in ethanol production here suggests that targeting protein post-translational modification is a promising new approach for inactivation of multiple enzymes simultaneously for metabolic engineering.

  9. Elimination of hydrogenase active site assembly blocks H2 production and increases ethanol yield in Clostridium thermocellum

    DOE PAGESBeta

    Biswas, Ranjita; Zheng, Tianyong; Olson, Daniel G.; Lynd, Lee R.; Guss, Adam M.

    2015-02-01

    The native ability of Clostridium thermocellum to rapidly consume cellulose and produce ethanol makes it a leading candidate for a consolidated bioprocessing (CBP) biofuel production strategy. C. thermocellum also synthesizes lactate, formate, acetate, H2, and amino acids that compete with ethanol production for carbon and electrons. Elimination of H2 production could redirect carbon flux towards ethanol production by making more electrons available for acetyl-CoA reduction to ethanol. C. thermocellum encodes four hydrogenases and rather than delete each individually, we targeted a hydrogenase maturase gene (hydG), involved in converting the three [FeFe] hydrogenase apoenzymes into holoenzymes. Further deletion of the [NiFe]more » hydrogenase (ech) resulted in a mutant that functionally lacks all four hydrogenases. H2 production in hydG ech was undetectable and ethanol yield increased nearly 2-fold compared to wild type. Interestingly, mutant growth improved upon the addition of acetate, which led to increased expression of genes related to sulfate metabolism, suggesting these mutants may use sulfate as a terminal electron acceptor to balance redox reactions. Genomic analysis of hydG revealed a mutation in adhE, resulting in a strain with both NADH- and NADPH-dependent alcohol dehydrogenase activities. While this same adhE mutation is found in ethanol tolerant C. thermocellum strain E50C, hydG and hydG ech are not more ethanol tolerant than wild type, illustrating the complicated interactions between redox balancing and ethanol tolerance in C. thermocellum. The dramatic increase in ethanol production here suggests that targeting protein post-translational modification is a promising new approach for inactivation of multiple enzymes simultaneously for metabolic engineering.« less

  10. Reversible oxygen-tolerant hydrogenase carried by free-living N2-fixing bacteria isolated from the rhizospheres of rice, maize, and wheat

    PubMed Central

    Roumagnac, Philippe; Richaud, Pierre; Barakat, Mohamed; Ortet, Philippe; Roncato, Marie-Anne; Heulin, Thierry; Peltier, Gilles; Achouak, Wafa; Cournac, Laurent

    2012-01-01

    Hydrogen production by microorganisms is often described as a promising sustainable and clean energy source, but still faces several obstacles, which prevent practical application. Among them, oxygen sensitivity of hydrogenases represents one of the major limitations hampering the biotechnological implementation of photobiological production processes. Here, we describe a hierarchical biodiversity-based approach, including a chemochromic screening of hydrogenase activity of hundreds of bacterial strains collected from several ecosystems, followed by mass spectrometry measurements of hydrogenase activity of a selection of the H2-oxidizing bacterial strains identified during the screen. In all, 131 of 1266 strains, isolated from cereal rhizospheres and basins containing irradiating waste, were scored as H2-oxidizing bacteria, including Pseudomonas sp., Serratia sp., Stenotrophomonas sp., Enterobacter sp., Rahnella sp., Burkholderia sp., and Ralstonia sp. isolates. Four free-living N2-fixing bacteria harbored a high and oxygen-tolerant hydrogenase activity, which was not fully inhibited within entire cells up to 150–250 μmol/L O2 concentration or within soluble protein extracts up to 25–30 μmol/L. The only hydrogenase-related genes that we could reveal in these strains were of the hyc type (subunits of formate hydrogenlyase complex). The four free-living N2-fixing bacteria were closely related to Enterobacter radicincitans based on the sequences of four genes (16S rRNA, rpoB, hsp60, and hycE genes). These results should bring interesting prospects for microbial biohydrogen production and might have ecophysiological significance for bacterial adaptation to the oxic–anoxic interfaces in the rhizosphere. PMID:23233392

  11. Energy-converting [NiFe] hydrogenases from archaea and extremophiles: ancestors of complex I.

    PubMed

    Hedderich, Reiner

    2004-02-01

    [NiFe] hydrogenases are well-characterized enzymes that have a key function in the H2 metabolism of various microorganisms. In the recent years a subfamily of [NiFe] hydrogenases with unique properties has been identified. The members of this family form multisubunit membrane-bound enzyme complexes composed of at least four hydrophilic and two integral membrane proteins. These six conserved subunits, which built the core of these hydrogenases, have closely related counterparts in energy-conserving NADH:quinone oxidoreductases (complex I). However, the reaction catalyzed by these hydrogenases differs significantly from the reaction catalyzed by complex I. For some of these hydrogenases the physiological role is to catalyze the reduction of H+ with electrons derived from reduced ferredoxins or poly-ferredoxins. This exergonic reaction is coupled to energy conservation by means of electron-transport phosphorylation. Other members of this hydrogenase family mainly function to provide the cell with reduced ferredoxin with H2 as electron donor in a reaction driven by reverse electron transport. As complex I these hydrogenases function as ion pumps and have therefore been designated as energy-converting [NiFe] hydrogenases.

  12. Hydrogenase activity in the thermophile mastigocladus laminosus

    SciTech Connect

    Benemann, J.R.; Miyamoto, K.; Hallenbeck, P.C.; Murry, M.A.

    1982-06-30

    Hydrogenase activity in the thermophilic cyanobacterium, Mastigocladus laminosus was studied both in vivo and in vitro. In vivo hydrogen consumption required oxygen but not light, was about ten-fold higher than in mesophilic cyanobacteria, and was relatively insensitive to carbon monoxide. H/sub 2/-supported acetylene reduction in reductant-limited cultures was a light-dependent, but O/sub 2/-independent reaction. In vitro hydrogen evolution was unaffected by carbon monoxide, and this activity could be partially purified using a procedure developed for Anabaena cylindrica.

  13. Wiring-up hydrogenase with single-walled carbon nanotubes.

    PubMed

    McDonald, Timothy J; Svedruzic, Drazenka; Kim, Yong-Hyun; Blackburn, Jeffrey L; Zhang, S B; King, Paul W; Heben, Michael J

    2007-11-01

    Many envision a future where hydrogen is the centerpiece of a sustainable, carbon-free energy supply. For example, the energy in sunlight may be stored by splitting water into H2 and O2 using inorganic semiconductors and photoelectrochemical approaches or with artificial photosynthetic systems that seek to mimic the light absorption, energy transfer, electron transfer, and redox catalysis that occurs in green plants. Unfortunately, large scale deployment of artificial water-splitting technologies may be impeded by the need for the large amounts of precious metals required to catalyze the multielectron water-splitting reactions. Nature provides a variety of microbes that can activate the dihydrogen bond through the catalytic activity of [NiFe] and [FeFe] hydrogenases, and photobiological approaches to water splitting have been advanced. One may also consider a biohybrid approach; however, it is difficult to interface these sensitive, metalloenzymes to other materials and systems. Here we show that surfactant-suspended carbon single-walled nanotubes (SWNTs) spontaneously self-assemble with [FeFe] hydrogenases in solution to form catalytically active biohybrids. Photoluminescence excitation and Raman spectroscopy studies show that SWNTs act as molecular wires to make electrical contact to the biocatalytic region of hydrogenase. Hydrogenase mediates electron injection into nanotubes having appropriately positioned lowest occupied molecular orbital levels when the H2 partial pressure is varied. The hydrogenase is strongly attached to the SWNTs, so mass transport effects are eliminated and the absolute potential of the electronic levels of the nanotubes can be unambiguously measured. Our findings reveal new nanotube physics and represent the first example of "wiring-up" an hydrogenase with another nanoscale material. This latter advance offers a nonprecious metal route to the design of new biohybrid architectures and building blocks for hydrogen-related technologies

  14. Function of Periplasmic Hydrogenases in the Sulfate-Reducing Bacterium Desulfovibrio vulgaris Hildenborough▿ †

    PubMed Central

    Caffrey, Sean M.; Park, Hyung-Soo; Voordouw, Johanna K.; He, Zhili; Zhou, Jizhong; Voordouw, Gerrit

    2007-01-01

    The sulfate-reducing bacterium Desulfovibrio vulgaris Hildenborough possesses four periplasmic hydrogenases to facilitate the oxidation of molecular hydrogen. These include an [Fe] hydrogenase, an [NiFeSe] hydrogenase, and two [NiFe] hydrogenases encoded by the hyd, hys, hyn1, and hyn2 genes, respectively. In order to understand their cellular functions, we have compared the growth rates of existing (hyd and hyn1) and newly constructed (hys and hyn-1 hyd) mutants to those of the wild type in defined media in which lactate or hydrogen at either 5 or 50% (vol/vol) was used as the sole electron donor for sulfate reduction. Only strains missing the [Fe] hydrogenase were significantly affected during growth with lactate or with 50% (vol/vol) hydrogen as the sole electron donor. When the cells were grown at low (5% [vol/vol]) hydrogen concentrations, those missing the [NiFeSe] hydrogenase suffered the greatest impairment. The growth rate data correlated strongly with gene expression results obtained from microarray hybridizations and real-time PCR using mRNA extracted from cells grown under the three conditions. Expression of the hys genes followed the order 5% hydrogen > 50% hydrogen > lactate, whereas expression of the hyd genes followed the reverse order. These results suggest that growth with lactate and 50% hydrogen is associated with high intracellular hydrogen concentrations, which are best captured by the higher activity, lower affinity [Fe] hydrogenase. In contrast, growth with 5% hydrogen is associated with a low intracellular hydrogen concentration, requiring the lower activity, higher affinity [NiFeSe] hydrogenase. PMID:17601789

  15. Function of Periplasmic Hydrogenases in the Sulfate-ReducingBacterium Desulfovibrio vulgaris Hildenborough

    SciTech Connect

    Caffrey, Sean M.; Park, Hyung-Soo; Voordouw, Johanna K.; He,Zhili; Zhou, Jizhong; Voordouw, Gerrit

    2007-09-24

    The sulfate-reducing bacterium Desulfovibrio vulgarisHildenborough possesses four periplasmic hydrogenases to facilitate theoxidation of molecular hydrogen. These include an [Fe]hydrogenase, an[NiFeSe]hydrogenase, and two [NiFe]hydrogenases encoded by the hyd,hys, hyn1, and hyn2 genes, respectively. In order to understand theircellular functions, we have compared the growth rates of existing (hydand hyn1) and newly constructed (hys and hyn-1 hyd) mutants to those ofthe wild type in defined media in which lactate or hydrogen at either 5or 50 percent (vol/vol) was used as the sole electron donor for sulfatereduction. Only strains missing the [Fe]hydrogenase were significantlyaffected during growth with lactate or with 50 percent (vol/vol) hydrogenas the sole electron donor. When the cells were grown at low (5 percent[vol/vol]) hydrogen concentrations, those missing the [NiFeSe]hydrogenase suffered the greatest impairment. The growth rate datacorrelated strongly with gene expression results obtained from microarrayhybridizations and real-time PCR using mRNA extracted from cells grownunder the three conditions. Expression of the hys genes followed theorder 5 percent hydrogen>50 percent hydrogen>lactate, whereasexpression of the hyd genes followed the reverse order. These resultssuggest that growth with lactate and 50 percent hydrogen is associatedwith high intracellular hydrogen concentrations, which are best capturedby the higher activity, lower affinity [Fe]hydrogenase. In contrast,growth with 5 percent hydrogen is associated with a low intracellularhydrogen concentration, requiring the lower activity, higher affinity[NiFeSe]hydrogenase.

  16. Mutational analysis of the hyc-operon determining the relationship between hydrogenase-3 and NADH pathway in Enterobacter aerogenes.

    PubMed

    Pi, Jian; Jawed, Muhammad; Wang, Jun; Xu, Li; Yan, Yunjun

    2016-01-01

    In this study, the hydrogenase-3 gene cluster (hycDEFGH) was isolated and identified from Enterobacter aerogenes CCTCC AB91102. All gene products were highly homologous to the reported bacterial hydrogenase-3 (Hyd-3) proteins. The genes hycE, hycF, hycG encoding the subunits of hydrogenase-3 were targeted for genetic knockout to inhibit the FHL hydrogen production pathway via the Red recombination system, generating three mutant strains AB91102-E (ΔhycE), AB91102-F (ΔhycF) and AB91102-G (ΔhycG). Deletion of the three genes affected the integrity of hydrogenase-3. The hydrogen production experiments with the mutant strains showed that no hydrogen was detected compared with the wild type (0.886 mol/mol glucose), demonstrating that knocking out any of the three genes could inhibit NADH hydrogen production pathway. Meanwhile, the metabolites of the mutant strains were significantly changed in comparison with the wild type, indicating corresponding changes in metabolic flux by mutation. Additionally, the activity of NADH-mediated hydrogenase was found to be nil in the mutant strains. The chemostat experiments showed that the NADH/NAD(+) ratio of the mutant strains increased nearly 1.4-fold compared with the wild type. The NADH-mediated hydrogenase activity and NADH/NAD(+) ratio analysis both suggested that NADH pathway required the involvement of the electron transport chain of hydrogenase-3.

  17. Dual role of HupF in the biosynthesis of [NiFe] hydrogenase in Rhizobium leguminosarum

    PubMed Central

    2012-01-01

    Background [NiFe] hydrogenases are enzymes that catalyze the oxidation of hydrogen into protons and electrons, to use H2 as energy source, or the production of hydrogen through proton reduction, as an escape valve for the excess of reduction equivalents in anaerobic metabolism. Biosynthesis of [NiFe] hydrogenases is a complex process that occurs in the cytoplasm, where a number of auxiliary proteins are required to synthesize and insert the metal cofactors into the enzyme structural units. The endosymbiotic bacterium Rhizobium leguminosarum requires the products of eighteen genes (hupSLCDEFGHIJKhypABFCDEX) to synthesize an active hydrogenase. hupF and hupK genes are found only in hydrogenase clusters from bacteria expressing hydrogenase in the presence of oxygen. Results HupF is a HypC paralogue with a similar predicted structure, except for the C-terminal domain present only in HupF. Deletion of hupF results in the inability to process the hydrogenase large subunit HupL, and also in reduced stability of this subunit when cells are exposed to high oxygen tensions. A ΔhupF mutant was fully complemented for hydrogenase activity by a C-terminal deletion derivative under symbiotic, ultra low-oxygen tensions, but only partial complementation was observed in free living cells under higher oxygen tensions (1% or 3%). Co-purification experiments using StrepTag-labelled HupF derivatives and mass spectrometry analysis indicate the existence of a major complex involving HupL and HupF, and a less abundant HupF-HupK complex. Conclusions The results indicate that HupF has a dual role during hydrogenase biosynthesis: it is required for hydrogenase large subunit processing and it also acts as a chaperone to stabilize HupL when hydrogenase is synthesized in the presence of oxygen. PMID:23136881

  18. Cyanide inactivation of hydrogenase from Azotobacter vinelandii

    SciTech Connect

    Seefeldt, L.C.; Arp, D.J. )

    1989-06-01

    The effects of cyanide on membrane-associated and purified hydrogenase from Azotobacter vinelandii were characterized. Inactivation of hydrogenase by cyanide was dependent on the activity (oxidation) state of the enzyme. Active (reduced) hydrogenase showed no inactivation when treated with cyanide over several hours. Treatment of reversibly inactive (oxidized) states of both membrane-associated and purified hydrogenase, however, resulted in a time-dependent, irreversible loss of hydrogenase activity. The rate of cyanide inactivation was dependent on the cyanide concentration and was an apparent first-order process for purified enzyme (bimolecular rate constant, 23.1 M{sup {minus}1} min{sup {minus}1} for CN{sup {minus}}). The rate of inactivation decreased with decreasing pH. ({sup 14}C)cyanide remained associated with cyanide-inactivated hydrogenase after gel filtration chromatography, with a stoichiometry of 1.7 mol of cyanide bound per mol of inactive enzyme. The presence of saturating concentrations of CO had no effect on the rate or extent of cyanide inactivation of hydrogenases. The results indicate that cyanide can cause a time-dependent, irreversible inactivation of hydrogenase in the oxidized, activatable state but has no effect when hydrogenase is in the reduced, active state.

  19. Hydrogenase- and Outer Membrane c-Type Cytochrome-Facilitated Reduction of Technetium(VII) by Shewanella oneidensis MR-1

    SciTech Connect

    Marshall, Matthew J.; Plymale, Andrew E.; Kennedy, David W.; Shi, Liang; Wang, Zheming; Reed, Samantha B.; Dohnalkova, Alice; Simonson, Cody J.; Liu, Chongxuan; Saffarini, Daad; Romine, Margaret F.; Zachara, John M.; Beliaev, Alex S.; Fredrickson, Jim K.

    2008-01-15

    Pertechnetate, 99Tc(VII)O4-, is a highly mobile radionuclide contaminant at U.S. Department of Energy sites that can be enzymatically reduced by a range of anaerobic and facultatively anaerobic microorganisms, including Shewanella oneidensis MR-1, to poorly soluble Tc(IV)O2(s). In other microorganisms, Tc(VII)O4- reduction is generally considered to be catalyzed by hydrogenase. Here, we provide evidence that although the NiFe hydrogenase of MR-1 was involved in the H2-driven reduction of Tc(VII)O4- (presumably through a direct coupling of H2 oxidation and Tc(VII) reduction), the deletion of both hydrogenase genes did not completely eliminate the ability of MR-1 to reduce Tc(VII). With lactate as the electron donor, mutants lacking the outer membrane c-type cytochromes MtrC and OmcA or the proteins required for the maturation of c-type cytochromes were defective in reducing Tc(VII) to nanoparticulate TcO2·nH2O(s) relative to MR-1 or a NiFe hydrogenase mutant. In addition, reduced MtrC and OmcA were oxidized by Tc(VII)O4-, confirming the capacity for direct electron transfer from these OMCs to TcO4-. c-Type cytochrome-catalyzed Tc(VII) reduction could be a potentially important mechanism in environments where organic electron donor concentrations are sufficient to allow this reaction to dominate.

  20. Identification of an uptake hydrogenase for hydrogen-dependent dissimilatory azoreduction by Shewanella decolorationis S12.

    PubMed

    Hong, Yi-Guo; Guo, Jun; Sun, Guo-Ping

    2008-09-01

    Shewanella decolorationis S12, a representative dissimilatory azo-reducing bacterium of Shewanella genus, can grow by coupling the oxidation of hydrogen to the reduction of azo compounds as the sole electron acceptor, indicating that an uptake hydrogenase is an important component for electron transfer for azoreduction. For searching to the uptake hydrogenase in the genome of S. decolorationis, two operons, hyd and hya, were cloned and sequenced, which encode periplasmically oriented Fe-only hydrogenase and a Ni-Fe hydrogenase, respectively, according to the homologous comparison with other bacterial hydrogenases. In order to assess the roles of these two enzymes in hydrogen-dependent azoreduction and growth, hyd- and hya-deficient mutants were generated by gene replacement. Hya was found to be required for hydrogen-dependent reduction of azo compound by resting cell suspensions and to be essential for growth with hydrogen as electron donor and azo compound as electron acceptor. Hyd, in contrast, was not. These findings suggest that Hya is an essential respiratory hydrogenase of dissimilatory azoreduction in S. decolorationis.

  1. [NiFeSe]-hydrogenase chemistry.

    PubMed

    Wombwell, Claire; Caputo, Christine A; Reisner, Erwin

    2015-11-17

    The development of technology for the inexpensive generation of the renewable energy vector H2 through water splitting is of immediate economic, ecological, and humanitarian interest. Recent interest in hydrogenases has been fueled by their exceptionally high catalytic rates for H2 production at a marginal overpotential, which is presently only matched by the nonscalable noble metal platinum. The mechanistic understanding of hydrogenase function guides the design of synthetic catalysts, and selection of a suitable hydrogenase enables direct applications in electro- and photocatalysis. [FeFe]-hydrogenases display excellent H2 evolution activity, but they are irreversibly damaged upon exposure to O2, which currently prevents their use in full water splitting systems. O2-tolerant [NiFe]-hydrogenases are known, but they are typically strongly biased toward H2 oxidation, while H2 production by [NiFe]-hydrogenases is often product (H2) inhibited. [NiFeSe]-hydrogenases are a subclass of [NiFe]-hydrogenases with a selenocysteine residue coordinated to the active site nickel center in place of a cysteine. They exhibit a combination of unique properties that are highly advantageous for applications in water splitting compared with other hydrogenases. They display a high H2 evolution rate with marginal inhibition by H2 and tolerance to O2. [NiFeSe]-hydrogenases are therefore one of the most active molecular H2 evolution catalysts applicable in water splitting. Herein, we summarize our recent progress in exploring the unique chemistry of [NiFeSe]-hydrogenases through biomimetic model chemistry and the chemistry with [NiFeSe]-hydrogenases in semiartificial photosynthetic systems. We gain perspective from the structural, spectroscopic, and electrochemical properties of the [NiFeSe]-hydrogenases and compare them with the chemistry of synthetic models of this hydrogenase active site. Our synthetic models give insight into the effects on the electronic properties and reactivity of

  2. [NiFeSe]-hydrogenase chemistry.

    PubMed

    Wombwell, Claire; Caputo, Christine A; Reisner, Erwin

    2015-11-17

    The development of technology for the inexpensive generation of the renewable energy vector H2 through water splitting is of immediate economic, ecological, and humanitarian interest. Recent interest in hydrogenases has been fueled by their exceptionally high catalytic rates for H2 production at a marginal overpotential, which is presently only matched by the nonscalable noble metal platinum. The mechanistic understanding of hydrogenase function guides the design of synthetic catalysts, and selection of a suitable hydrogenase enables direct applications in electro- and photocatalysis. [FeFe]-hydrogenases display excellent H2 evolution activity, but they are irreversibly damaged upon exposure to O2, which currently prevents their use in full water splitting systems. O2-tolerant [NiFe]-hydrogenases are known, but they are typically strongly biased toward H2 oxidation, while H2 production by [NiFe]-hydrogenases is often product (H2) inhibited. [NiFeSe]-hydrogenases are a subclass of [NiFe]-hydrogenases with a selenocysteine residue coordinated to the active site nickel center in place of a cysteine. They exhibit a combination of unique properties that are highly advantageous for applications in water splitting compared with other hydrogenases. They display a high H2 evolution rate with marginal inhibition by H2 and tolerance to O2. [NiFeSe]-hydrogenases are therefore one of the most active molecular H2 evolution catalysts applicable in water splitting. Herein, we summarize our recent progress in exploring the unique chemistry of [NiFeSe]-hydrogenases through biomimetic model chemistry and the chemistry with [NiFeSe]-hydrogenases in semiartificial photosynthetic systems. We gain perspective from the structural, spectroscopic, and electrochemical properties of the [NiFeSe]-hydrogenases and compare them with the chemistry of synthetic models of this hydrogenase active site. Our synthetic models give insight into the effects on the electronic properties and reactivity of

  3. Diversity and transcription of proteases involved in the maturation of hydrogenases in Nostoc punctiforme ATCC 29133 and Nostoc sp. strain PCC 7120

    PubMed Central

    2009-01-01

    Background The last step in the maturation process of the large subunit of [NiFe]-hydrogenases is a proteolytic cleavage of the C-terminal by a hydrogenase specific protease. Contrary to other accessory proteins these hydrogenase proteases are believed to be specific whereby one type of hydrogenases specific protease only cleaves one type of hydrogenase. In cyanobacteria this is achieved by the gene product of either hupW or hoxW, specific for the uptake or the bidirectional hydrogenase respectively. The filamentous cyanobacteria Nostoc punctiforme ATCC 29133 and Nostoc sp strain PCC 7120 may contain a single uptake hydrogenase or both an uptake and a bidirectional hydrogenase respectively. Results In order to examine these proteases in cyanobacteria, transcriptional analyses were performed of hupW in Nostoc punctiforme ATCC 29133 and hupW and hoxW in Nostoc sp. strain PCC 7120. These studies revealed numerous transcriptional start points together with putative binding sites for NtcA (hupW) and LexA (hoxW). In order to investigate the diversity and specificity among hydrogeanse specific proteases we constructed a phylogenetic tree which revealed several subgroups that showed a striking resemblance to the subgroups previously described for [NiFe]-hydrogenases. Additionally the proteases specificity was also addressed by amino acid sequence analysis and protein-protein docking experiments with 3D-models derived from bioinformatic studies. These studies revealed a so called "HOXBOX"; an amino acid sequence specific for protease of Hox-type which might be involved in docking with the large subunit of the hydrogenase. Conclusion Our findings suggest that the hydrogenase specific proteases are under similar regulatory control as the hydrogenases they cleave. The result from the phylogenetic study also indicates that the hydrogenase and the protease have co-evolved since ancient time and suggests that at least one major horizontal gene transfer has occurred. This co

  4. Nitrogen Fixation and Hydrogen Metabolism in Relation to the Dissolved Oxygen Tension in Chemostat Cultures of the Wild Type and a Hydrogenase-Negative Mutant of Azorhizobium caulinodans

    PubMed Central

    Boogerd, Fred C.; Ferdinandy-van Vlerken, Marijke M. A.; Mawadza, Crispen; Pronk, Annemieke F.; Stouthamer, Adriaan H.; van Verseveld, Henk W.

    1994-01-01

    Both the wild type and an isogenic hydrogenase-negative mutant of Azorhizobium caulinodans growing ex planta on N2 as the N source were studied in succinate-limited steady-state chemostat cultures under 0.2 to 3.0% dissolved O2 tension. Production or consumption of O2, H2, and CO2 was measured with an on-line-connected mass spectrometer. In the range of 0.2 to 3.0%, growth of both the wild type and the mutant was equally dependent on the dissolved O2 tension: the growth yield decreased, and the specific O2 consumption and CO2 production increased. A similar dependency on the dissolved O2 tension was found for the mutant with 2.5% H2 in the influent gas. The H2/N2 ratio (moles of H2 evolved per mole of N2 consumed via nitrogenase) of the mutant, growing with or without 2.5% H2, increased with increasing dissolved O2 tensions. This increase in the H2/N2 ratio was small but significant. The dependencies of the ATP/N2 ratio (moles of ATP consumed per mole of N2 fixed) and the ATP/2e- ratio [moles of ATP consumed per mole of electron pairs transferred from NAD(P)H to nitrogenase] on the dissolved O2 tension were estimated. These dependencies were interpreted in terms of the physiological concepts of respiratory protection and autoprotection. PMID:16349280

  5. Determining Semantically Related Significant Genes.

    PubMed

    Taha, Kamal

    2014-01-01

    GO relation embodies some aspects of existence dependency. If GO term xis existence-dependent on GO term y, the presence of y implies the presence of x. Therefore, the genes annotated with the function of the GO term y are usually functionally and semantically related to the genes annotated with the function of the GO term x. A large number of gene set enrichment analysis methods have been developed in recent years for analyzing gene sets enrichment. However, most of these methods overlook the structural dependencies between GO terms in GO graph by not considering the concept of existence dependency. We propose in this paper a biological search engine called RSGSearch that identifies enriched sets of genes annotated with different functions using the concept of existence dependency. We observe that GO term xcannot be existence-dependent on GO term y, if x- and y- have the same specificity (biological characteristics). After encoding into a numeric format the contributions of GO terms annotating target genes to the semantics of their lowest common ancestors (LCAs), RSGSearch uses microarray experiment to identify the most significant LCA that annotates the result genes. We evaluated RSGSearch experimentally and compared it with five gene set enrichment systems. Results showed marked improvement.

  6. Molecular Dynamics Studies of Proton Transport in Hydrogenase and Hydrogenase Mimics.

    PubMed

    Ginovska, B; Raugei, S; Shaw, W J

    2016-01-01

    There is extensive interest in hydrogenases based on their ability to rapidly and efficiently interconvert H2 with protons and electrons, and their (typically) superior function relative to molecular mimics. Understanding the function of enzymes is one approach to implementing design features to make better catalysts and is an approach we have implemented in our work. In this review, we will discuss our efforts to develop design principles from enzymes, with specific focus on proton transport. We will also present computational studies of the mimics we have investigated with similar methodologies. We will discuss the mechanisms used by small scaffolds on molecular mimics which in many cases are surprisingly similar to those used by nature, while in other cases, computational analysis allowed us to reveal an unexpected role. Computational methods provide one of the best ways, and in some cases, the only way, to gain insight into the mechanistic details of enzymes. In this review, we illustrate the general computational strategy we used to study the proton pathway of [FeFe]-hydrogenase, and the similar strategy to investigate small molecules. We present the main results we obtained and how our computational work stimulated or worked in concert with experimental investigations. We also focus on estimation of errors and convergence of properties in the simulations. These studies demonstrate the powerful results that can be obtained by the close pairing of experimental and theoretical approaches. PMID:27497163

  7. Genomic and metagenomic surveys of hydrogenase distribution indicate H2 is a widely utilised energy source for microbial growth and survival.

    PubMed

    Greening, Chris; Biswas, Ambarish; Carere, Carlo R; Jackson, Colin J; Taylor, Matthew C; Stott, Matthew B; Cook, Gregory M; Morales, Sergio E

    2016-03-01

    Recent physiological and ecological studies have challenged the long-held belief that microbial metabolism of molecular hydrogen (H2) is a niche process. To gain a broader insight into the importance of microbial H2 metabolism, we comprehensively surveyed the genomic and metagenomic distribution of hydrogenases, the reversible enzymes that catalyse the oxidation and evolution of H2. The protein sequences of 3286 non-redundant putative hydrogenases were curated from publicly available databases. These metalloenzymes were classified into multiple groups based on (1) amino acid sequence phylogeny, (2) metal-binding motifs, (3) predicted genetic organisation and (4) reported biochemical characteristics. Four groups (22 subgroups) of [NiFe]-hydrogenase, three groups (6 subtypes) of [FeFe]-hydrogenases and a small group of [Fe]-hydrogenases were identified. We predict that this hydrogenase diversity supports H2-based respiration, fermentation and carbon fixation processes in both oxic and anoxic environments, in addition to various H2-sensing, electron-bifurcation and energy-conversion mechanisms. Hydrogenase-encoding genes were identified in 51 bacterial and archaeal phyla, suggesting strong pressure for both vertical and lateral acquisition. Furthermore, hydrogenase genes could be recovered from diverse terrestrial, aquatic and host-associated metagenomes in varying proportions, indicating a broad ecological distribution and utilisation. Oxygen content (pO2) appears to be a central factor driving the phylum- and ecosystem-level distribution of these genes. In addition to compounding evidence that H2 was the first electron donor for life, our analysis suggests that the great diversification of hydrogenases has enabled H2 metabolism to sustain the growth or survival of microorganisms in a wide range of ecosystems to the present day. This work also provides a comprehensive expanded system for classifying hydrogenases and identifies new prospects for investigating H2

  8. Hydrogenase polypeptide and methods of use

    DOEpatents

    Adams, Michael W.W.; Hopkins, Robert C.; Jenney, JR, Francis E.; Sun, Junsong

    2016-02-02

    Provided herein are polypeptides having hydrogenase activity. The polypeptide may be multimeric, and may have hydrogenase activity of at least 0.05 micromoles H.sub.2 produced min.sup.-1 mg protein.sup.-1. Also provided herein are polynucleotides encoding the polypeptides, genetically modified microbes that include polynucleotides encoding one or more subunits of the multimeric polypeptide, and methods for making and using the polypeptides.

  9. Genetic diversity of hydrogen-producing bacteria in an acidophilic ethanol-H2-coproducing system, analyzed using the [Fe]-hydrogenase gene.

    PubMed

    Xing, Defeng; Ren, Nanqi; Rittmann, Bruce E

    2008-02-01

    Hydrogen gas (H2) produced by bacterial fermentation of biomass can be a sustainable energy source. The ability to produce H2 gas during anaerobic fermentation was previously thought to be restricted to a few species within the genera Clostridium and Enterobacter. This work reports genomic evidence for the presence of novel H2-producing bacteria (HPB) in acidophilic ethanol-H2-coproducing communities that were enriched using molasses wastewater. The majority of the enriched dominant populations in the acidophilic ethanol-H2-coproducing system were affiliated with low-G+C-content gram-positive bacteria, Bacteroidetes, and Actinobacteria, based on the 16S rRNA gene. However, PCR primers designed to specifically target bacterial hydA yielded 17 unique hydA sequences whose amino acid sequences differed from those of known HPB. The putative ethanol-H2-coproducing bacteria comprised 11 novel phylotypes closely related to Ethanoligenens harbinense, Clostridium thermocellum, and Clostridium saccharoperbutylacetonicum. Furthermore, analysis of the alcohol dehydrogenase isoenzyme also pointed to an E. harbinense-like organism, which is known to have a high conversion rate of carbohydrate to H2 and ethanol. We also found six novel HPB that were associated with lactate-, propionate-, and butyrate-oxidizing bacteria in the acidophilic H2-producing sludge. Thus, the microbial ecology of mesophilic and acidophilic H2 fermentation involves many other bacteria in addition to Clostridium and Enterobacter.

  10. Roles of HynAB and Ech, the Only Two Hydrogenases Found in the Model Sulfate Reducer Desulfovibrio gigas

    PubMed Central

    Morais-Silva, Fabio O.; Santos, Catia I.; Rodrigues, Rute

    2013-01-01

    Sulfate-reducing bacteria are characterized by a high number of hydrogenases, which have been proposed to contribute to the overall energy metabolism of the cell, but exactly in what role is not clear. Desulfovibrio spp. can produce or consume H2 when growing on organic or inorganic substrates in the presence or absence of sulfate. Because of the presence of only two hydrogenases encoded in its genome, the periplasmic HynAB and cytoplasmic Ech hydrogenases, Desulfovibrio gigas is an excellent model organism for investigation of the specific function of each of these enzymes during growth. In this study, we analyzed the physiological response to the deletion of the genes that encode the two hydrogenases in D. gigas, through the generation of ΔechBC and ΔhynAB single mutant strains. These strains were analyzed for the ability to grow on different substrates, such as lactate, pyruvate, and hydrogen, under respiratory and fermentative conditions. Furthermore, the expression of both hydrogenase genes in the three strains studied was assessed through quantitative reverse transcription-PCR. The results demonstrate that neither hydrogenase is essential for growth on lactate-sulfate, indicating that hydrogen cycling is not indispensable. In addition, the periplasmic HynAB enzyme has a bifunctional activity and is required for growth on H2 or by fermentation of pyruvate. Therefore, this enzyme seems to play a dominant role in D. gigas hydrogen metabolism. PMID:23974026

  11. Hydrogenases in green algae: do they save the algae's life and solve our energy problems?

    PubMed

    Happe, Thomas; Hemschemeier, Anja; Winkler, Martin; Kaminski, Annette

    2002-06-01

    Green algae are the only known eukaryotes with both oxygenic photosynthesis and a hydrogen metabolism. Recent physiological and genetic discoveries indicate a close connection between these metabolic pathways. The anaerobically inducible hydA genes of algae encode a special type of highly active [Fe]-hydrogenase. Electrons from reducing equivalents generated during fermentation enter the photosynthetic electron transport chain via the plastoquinone pool. They are transferred to the hydrogenase by photosystem I and ferredoxin. Thus, the [Fe]-hydrogenase is an electron 'valve' that enables the algae to survive under anaerobic conditions. During sulfur deprivation, illuminated algal cultures evolve large quantities of hydrogen gas, and this promises to be an alternative future energy source. PMID:12049920

  12. The Hydrogenase Chip: a tiling oligonucleotide DNA microarray technique for characterizing hydrogen-producing and -consuming microbes in microbial communities

    PubMed Central

    Marshall, Ian PG; Berggren, Dusty RV; Azizian, Mohammad F; Burow, Luke C; Semprini, Lewis; Spormann, Alfred M

    2012-01-01

    We developed a broad-ranging method for identifying key hydrogen-producing and consuming microorganisms through analysis of hydrogenase gene content and expression in complex anaerobic microbial communities. The method is based on a tiling hydrogenase gene oligonucleotide DNA microarray (Hydrogenase Chip), which implements a high number of probes per gene by tiling probe sequences across genes of interest at 1.67 × –2 × coverage. This design favors the avoidance of false positive gene identification in samples of DNA or RNA extracted from complex microbial communities. We applied this technique to interrogate interspecies hydrogen transfer in complex communities in (i) lab-scale reductive dehalogenating microcosms enabling us to delineate key H2-consuming microorganisms, and (ii) hydrogen-generating microbial mats where we found evidence for significant H2 production by cyanobacteria. Independent quantitative PCR analysis on selected hydrogenase genes showed that this Hydrogenase Chip technique is semiquantitative. We also determined that as microbial community complexity increases, specificity must be traded for sensitivity in analyzing data from tiling DNA microarrays. PMID:21993396

  13. Engineering Hyperthermophilic Archaeon Pyrococcus furiosus to Overproduce Its Cytoplasmic [NiFe]-Hydrogenase*

    PubMed Central

    Chandrayan, Sanjeev K.; McTernan, Patrick M.; Hopkins, R. Christopher; Sun, Junsong; Jenney, Francis E.; Adams, Michael W. W.

    2012-01-01

    The cytoplasmic hydrogenase (SHI) of the hyperthermophilic archaeon Pyrococcus furiosus is an NADP(H)-dependent heterotetrameric enzyme that contains a nickel-iron catalytic site, flavin, and six iron-sulfur clusters. It has potential utility in a range of bioenergy systems in vitro, but a major obstacle in its use is generating sufficient amounts. We have engineered P. furiosus to overproduce SHI utilizing a recently developed genetic system. In the overexpression (OE-SHI) strain, transcription of the four-gene SHI operon was under the control of a strong constitutive promoter, and a Strep-tag II was added to the N terminus of one subunit. OE-SHI and wild-type P. furiosus strains had similar rates of growth and H2 production on maltose. Strain OE-SHI had a 20-fold higher transcription of the polycistronic hydrogenase mRNA encoding SHI, and the specific activity of the cytoplasmic hydrogenase was ∼10-fold higher when compared with the wild-type strain, although the expression levels of genes encoding processing and maturation of SHI were the same in both strains. Overexpressed SHI was purified by a single affinity chromatography step using the Strep-tag II, and it and the native form had comparable activities and physical properties. Based on protein yield per gram of cells (wet weight), the OE-SHI strain yields a 100-fold higher amount of hydrogenase when compared with the highest homologous [NiFe]-hydrogenase system previously reported (from Synechocystis). This new P. furiosus system will allow further engineering of SHI and provide hydrogenase for efficient in vitro biohydrogen production. PMID:22157005

  14. Molecular detection of the clostridia in an anaerobic biohydrogen fermentation system by hydrogenase mRNA-targeted reverse transcription-PCR.

    PubMed

    Chang, Jui-Jen; Chen, Wei-En; Shih, Shiou-Yun; Yu, Sian-Jhong; Lay, Jiunn-Jyi; Wen, Fu-Shyan; Huang, Chieh-Chen

    2006-05-01

    Molecular biological approaches were developed to monitor the potential biohydrogen-producing clostridia in an anaerobic semisolid fermentation system that used brewery yeast waste as the fermentation substrate. The denaturing gradient gel electrophoresis with 16S rDNA gene-targeted polymerase chain reaction (PCR) analysis was employed to confirm the existence of clostridia in the system. Remarkably, reproducible nucleotide sequences of clostridia were obtained from different hydrogen production stages by using hydrogenase gene-targeted reverse transcription (RT)-PCR. These RNA-based information suggested that the predominant hydrogen-producing strains possess either a specific Clostridium pasteurianum-like or a specific Clostridium saccharobutylicum-like hydrogenase sequence. Comparison of the hydrogenase gene-targeted sequence profiles between PCR and RT-PCR revealed that the specific C. pasteurianum-like hydrogenase harboring bacterial strains were dominant in both mRNA and bacterial population level. On the other hand, the specific C. saccharobutylicum-like hydrogenase harboring strains expressed high level of hydrogenase mRNA but may not be dominant in population. Furthermore, quantitative real-time RT-PCR analysis showed the expression pattern of the clostridial hydrogenase mRNA and may serve as an activity index for the system.

  15. Cobaloxime-based artificial hydrogenases.

    PubMed

    Bacchi, Marine; Berggren, Gustav; Niklas, Jens; Veinberg, Elias; Mara, Michael W; Shelby, Megan L; Poluektov, Oleg G; Chen, Lin X; Tiede, David M; Cavazza, Christine; Field, Martin J; Fontecave, Marc; Artero, Vincent

    2014-08-01

    Cobaloximes are popular H2 evolution molecular catalysts but have so far mainly been studied in nonaqueous conditions. We show here that they are also valuable for the design of artificial hydrogenases for application in neutral aqueous solutions and report on the preparation of two well-defined biohybrid species via the binding of two cobaloxime moieties, {Co(dmgH)2} and {Co(dmgBF2)2} (dmgH2 = dimethylglyoxime), to apo Sperm-whale myoglobin (SwMb). All spectroscopic data confirm that the cobaloxime moieties are inserted within the binding pocket of the SwMb protein and are coordinated to a histidine residue in the axial position of the cobalt complex, resulting in thermodynamically stable complexes. Quantum chemical/molecular mechanical docking calculations indicated a coordination preference for His93 over the other histidine residue (His64) present in the vicinity. Interestingly, the redox activity of the cobalt centers is retained in both biohybrids, which provides them with the catalytic activity for H2 evolution in near-neutral aqueous conditions. PMID:25029381

  16. Cobaloxime-based artificial hydrogenases.

    PubMed

    Bacchi, Marine; Berggren, Gustav; Niklas, Jens; Veinberg, Elias; Mara, Michael W; Shelby, Megan L; Poluektov, Oleg G; Chen, Lin X; Tiede, David M; Cavazza, Christine; Field, Martin J; Fontecave, Marc; Artero, Vincent

    2014-08-01

    Cobaloximes are popular H2 evolution molecular catalysts but have so far mainly been studied in nonaqueous conditions. We show here that they are also valuable for the design of artificial hydrogenases for application in neutral aqueous solutions and report on the preparation of two well-defined biohybrid species via the binding of two cobaloxime moieties, {Co(dmgH)2} and {Co(dmgBF2)2} (dmgH2 = dimethylglyoxime), to apo Sperm-whale myoglobin (SwMb). All spectroscopic data confirm that the cobaloxime moieties are inserted within the binding pocket of the SwMb protein and are coordinated to a histidine residue in the axial position of the cobalt complex, resulting in thermodynamically stable complexes. Quantum chemical/molecular mechanical docking calculations indicated a coordination preference for His93 over the other histidine residue (His64) present in the vicinity. Interestingly, the redox activity of the cobalt centers is retained in both biohybrids, which provides them with the catalytic activity for H2 evolution in near-neutral aqueous conditions.

  17. Evolutionary and Biotechnological Implications of Robust Hydrogenase Activity in Halophilic Strains of Tetraselmis

    PubMed Central

    D'Adamo, Sarah; Jinkerson, Robert E.; Boyd, Eric S.; Brown, Susan L.; Baxter, Bonnie K.; Peters, John W.; Posewitz, Matthew C.

    2014-01-01

    Although significant advances in H2 photoproduction have recently been realized in fresh water algae (e.g. Chlamydomonas reinhardtii), relatively few studies have focused on H2 production and hydrogenase adaptations in marine or halophilic algae. Salt water organisms likely offer several advantages for biotechnological H2 production due to the global abundance of salt water, decreased H2 and O2 solubility in saline and hypersaline systems, and the ability of extracellular NaCl levels to influence metabolism. We screened unialgal isolates obtained from hypersaline ecosystems in the southwest United States and identified two distinct halophilic strains of the genus Tetraselmis (GSL1 and QNM1) that exhibit both robust fermentative and photo H2-production activities. The influence of salinity (3.5%, 5.5% and 7.0% w/v NaCl) on H2 production was examined during anoxic acclimation, with the greatest in vivo H2-production rates observed at 7.0% NaCl. These Tetraselmis strains maintain robust hydrogenase activity even after 24 h of anoxic acclimation and show increased hydrogenase activity relative to C. reinhardtii after extended anoxia. Transcriptional analysis of Tetraselmis GSL1 enabled sequencing of the cDNA encoding the FeFe-hydrogenase structural enzyme (HYDA) and its maturation proteins (HYDE, HYDEF and HYDG). In contrast to freshwater Chlorophyceae, the halophilic Tetraselmis GSL1 strain likely encodes a single HYDA and two copies of HYDE, one of which is fused to HYDF. Phylogenetic analyses of HYDA and concatenated HYDA, HYDE, HYDF and HYDG in Tetraselmis GSL1 fill existing knowledge gaps in the evolution of algal hydrogenases and indicate that the algal hydrogenases sequenced to date are derived from a common ancestor. This is consistent with recent hypotheses that suggest fermentative metabolism in the majority of eukaryotes is derived from a common base set of enzymes that emerged early in eukaryotic evolution with subsequent losses in some organisms. PMID

  18. Evolutionary and biotechnological implications of robust hydrogenase activity in halophilic strains of Tetraselmis.

    PubMed

    D'Adamo, Sarah; Jinkerson, Robert E; Boyd, Eric S; Brown, Susan L; Baxter, Bonnie K; Peters, John W; Posewitz, Matthew C

    2014-01-01

    Although significant advances in H2 photoproduction have recently been realized in fresh water algae (e.g. Chlamydomonas reinhardtii), relatively few studies have focused on H2 production and hydrogenase adaptations in marine or halophilic algae. Salt water organisms likely offer several advantages for biotechnological H2 production due to the global abundance of salt water, decreased H2 and O2 solubility in saline and hypersaline systems, and the ability of extracellular NaCl levels to influence metabolism. We screened unialgal isolates obtained from hypersaline ecosystems in the southwest United States and identified two distinct halophilic strains of the genus Tetraselmis (GSL1 and QNM1) that exhibit both robust fermentative and photo H2-production activities. The influence of salinity (3.5%, 5.5% and 7.0% w/v NaCl) on H2 production was examined during anoxic acclimation, with the greatest in vivo H2-production rates observed at 7.0% NaCl. These Tetraselmis strains maintain robust hydrogenase activity even after 24 h of anoxic acclimation and show increased hydrogenase activity relative to C. reinhardtii after extended anoxia. Transcriptional analysis of Tetraselmis GSL1 enabled sequencing of the cDNA encoding the FeFe-hydrogenase structural enzyme (HYDA) and its maturation proteins (HYDE, HYDEF and HYDG). In contrast to freshwater Chlorophyceae, the halophilic Tetraselmis GSL1 strain likely encodes a single HYDA and two copies of HYDE, one of which is fused to HYDF. Phylogenetic analyses of HYDA and concatenated HYDA, HYDE, HYDF and HYDG in Tetraselmis GSL1 fill existing knowledge gaps in the evolution of algal hydrogenases and indicate that the algal hydrogenases sequenced to date are derived from a common ancestor. This is consistent with recent hypotheses that suggest fermentative metabolism in the majority of eukaryotes is derived from a common base set of enzymes that emerged early in eukaryotic evolution with subsequent losses in some organisms. PMID

  19. Hydrogen Formation and Its Regulation in Ruminococcus albus: Involvement of an Electron-Bifurcating [FeFe]-Hydrogenase, of a Non-Electron-Bifurcating [FeFe]-Hydrogenase, and of a Putative Hydrogen-Sensing [FeFe]-Hydrogenase

    PubMed Central

    Zheng, Yanning; Kahnt, Jörg; Kwon, In Hyuk; Mackie, Roderick I.

    2014-01-01

    Ruminococcus albus 7 has played a key role in the development of the concept of interspecies hydrogen transfer. The rumen bacterium ferments glucose to 1.3 acetate, 0.7 ethanol, 2 CO2, and 2.6 H2 when growing in batch culture and to 2 acetate, 2 CO2, and 4 H2 when growing in continuous culture in syntrophic association with H2-consuming microorganisms that keep the H2 partial pressure low. The organism uses NAD+ and ferredoxin for glucose oxidation to acetyl coenzyme A (acetyl-CoA) and CO2, NADH for the reduction of acetyl-CoA to ethanol, and NADH and reduced ferredoxin for the reduction of protons to H2. Of all the enzymes involved, only the enzyme catalyzing the formation of H2 from NADH remained unknown. Here, we report that R. albus 7 grown in batch culture on glucose contained, besides a ferredoxin-dependent [FeFe]-hydrogenase (HydA2), a ferredoxin- and NAD-dependent electron-bifurcating [FeFe]-hydrogenase (HydABC) that couples the endergonic formation of H2 from NADH to the exergonic formation of H2 from reduced ferredoxin. Interestingly, hydA2 is adjacent to the hydS gene, which is predicted to encode an [FeFe]-hydrogenase with a C-terminal PAS domain. We showed that hydS and hydA2 are part of a larger transcriptional unit also harboring putative genes for a bifunctional acetaldehyde/ethanol dehydrogenase (Aad), serine/threonine protein kinase, serine/threonine protein phosphatase, and a redox-sensing transcriptional repressor. Since HydA2 and Aad are required only when R. albus grows at high H2 partial pressures, HydS could be a H2-sensing [FeFe]-hydrogenase involved in the regulation of their biosynthesis. PMID:25157086

  20. [NiFe] hydrogenase from Desulfovibrio desulfuricans ATCC 27774: gene sequencing, three-dimensional structure determination and refinement at 1.8 A and modelling studies of its interaction with the tetrahaem cytochrome c3.

    PubMed

    Matias, P M; Soares, C M; Saraiva, L M; Coelho, R; Morais, J; Le Gall, J; Carrondo, M A

    2001-01-01

    The primary and three-dimensional structures of a [NiFe] hydrogenase isolated from D. desulfitricans ATCC 27774 were determined, by nucleotide analysis and single-crystal X-ray crystallography. The three-dimensional structural model was refined to R=0.167 and Rfree=0.223 using data to 1.8 A resolution. Two unique structural features are observed: the [4Fe-4S] cluster nearest the [NiFe] centre has been modified [4Fe-3S-3O] by loss of one sulfur atom and inclusion of three oxygen atoms; a three-fold disorder was observed for Cys536 which binds to the nickel atom in the [NiFe] centre. Also, the bridging sulfur atom that caps the active site was found to have partial occupancy, thus corresponding to a partly activated enzyme. These structural features may have biological relevance. In particular, the two less-populated rotamers of Cys536 may be involved in the activation process of the enzyme, as well as in the catalytic cycle. Molecular modelling studies were carried out on the interaction between this [NiFe] hydrogenase and its physiological partner, the tetrahaem cytochrome c3 from the same organism. The lowest energy docking solutions were found to correspond to an interaction between the haem IV region in tetrahaem cytochrome c3 with the distal [4Fe-4S] cluster in [NiFe] hydrogenase. This interaction should correspond to efficient electron transfer and be physiologically relevant, given the proximity of the two redox centres and the fact that electron transfer decay coupling calculations show high coupling values and a short electron transfer pathway. On the other hand, other docking solutions have been found that, despite showing low electron transfer efficiency, may give clues on possible proton transfer mechanisms between the two molecules. PMID:11191224

  1. [FeFe]-Hydrogenase Abundance and Diversity along a Vertical Redox Gradient in Great Salt Lake, USA

    PubMed Central

    Boyd, Eric S.; Hamilton, Trinity L.; Swanson, Kevin D.; Howells, Alta E.; Baxter, Bonnie K.; Meuser, Jonathan E.; Posewitz, Matthew C.; Peters, John W.

    2014-01-01

    The use of [FeFe]-hydrogenase enzymes for the biotechnological production of H2 or other reduced products has been limited by their sensitivity to oxygen (O2). Here, we apply a PCR-directed approach to determine the distribution, abundance, and diversity of hydA gene fragments along co-varying salinity and O2 gradients in a vertical water column of Great Salt Lake (GSL), UT. The distribution of hydA was constrained to water column transects that had high salt and relatively low O2 concentrations. Recovered HydA deduced amino acid sequences were enriched in hydrophilic amino acids relative to HydA from less saline environments. In addition, they harbored interesting variations in the amino acid environment of the complex H-cluster metalloenzyme active site and putative gas transfer channels that may be important for both H2 transfer and O2 susceptibility. A phylogenetic framework was created to infer the accessory cluster composition and quaternary structure of recovered HydA protein sequences based on phylogenetic relationships and the gene contexts of known complete HydA sequences. Numerous recovered HydA are predicted to harbor multiple N- and C-terminal accessory iron-sulfur cluster binding domains and are likely to exist as multisubunit complexes. This study indicates an important role for [FeFe]-hydrogenases in the functioning of the GSL ecosystem and provides new target genes and variants for use in identifying O2 tolerant enzymes for biotechnological applications. PMID:25464382

  2. RAPD analysis and sequencing of ITS1/5.8S rRNA/ITS2 and Fe-hydrogenase as tools for genetic classification of potentially pathogenic isolates of Trichomonas gallinae.

    PubMed

    Sansano-Maestre, José; Martínez-Herrero, María Del Carmen; Garijo-Toledo, María Magdalena; Gómez-Muñoz, María Teresa

    2016-08-01

    Trichomonas gallinae is a worldwide parasite that causes oropharyngeal avian trichomonosis. During eight years, 60 axenic isolates were obtained from different bird species and characterized by three molecular methods: RAPD analysis and PCR-sequencing of ITS1/5.8S rRNA/ITS2 fragment and Fe-hydrogenase gene. We have found two genotypes of ITS1/5.8S rRNA/ITS2 widely distributed among bird populations, a new variant and also two sequences with mixed pattern. Genotype ITS-OBT-Tg-1 was associated with the presence of gross lesions in birds. We have found eight genotypes of the Fe-hydrogenase (A1, A2, C2, C2.1, C4, C5, C6 and C7), three of them are new reports (C5, C6 and C7), and also three sequences with mixed pattern. Subtype A1 of the Fe-hydrogenase was also related with the presence of lesions. RAPD analyses included most of the strains isolated from animals with lesions in one of the sub-clusters. Potentially pathogenic isolates of T. gallinae obtained in this study fulfill the following criteria with one exception: isolated from lesions+ITS-OBT-Tg-1 genotype+FeHyd A1+RAPD sub-cluster I2.

  3. RAPD analysis and sequencing of ITS1/5.8S rRNA/ITS2 and Fe-hydrogenase as tools for genetic classification of potentially pathogenic isolates of Trichomonas gallinae.

    PubMed

    Sansano-Maestre, José; Martínez-Herrero, María Del Carmen; Garijo-Toledo, María Magdalena; Gómez-Muñoz, María Teresa

    2016-08-01

    Trichomonas gallinae is a worldwide parasite that causes oropharyngeal avian trichomonosis. During eight years, 60 axenic isolates were obtained from different bird species and characterized by three molecular methods: RAPD analysis and PCR-sequencing of ITS1/5.8S rRNA/ITS2 fragment and Fe-hydrogenase gene. We have found two genotypes of ITS1/5.8S rRNA/ITS2 widely distributed among bird populations, a new variant and also two sequences with mixed pattern. Genotype ITS-OBT-Tg-1 was associated with the presence of gross lesions in birds. We have found eight genotypes of the Fe-hydrogenase (A1, A2, C2, C2.1, C4, C5, C6 and C7), three of them are new reports (C5, C6 and C7), and also three sequences with mixed pattern. Subtype A1 of the Fe-hydrogenase was also related with the presence of lesions. RAPD analyses included most of the strains isolated from animals with lesions in one of the sub-clusters. Potentially pathogenic isolates of T. gallinae obtained in this study fulfill the following criteria with one exception: isolated from lesions+ITS-OBT-Tg-1 genotype+FeHyd A1+RAPD sub-cluster I2. PMID:27473993

  4. Analyses of the Large Subunit Histidine-Rich Motif Expose an Alternative Proton Transfer Pathway in [NiFe] Hydrogenases

    PubMed Central

    Szőri-Dorogházi, Emma; Maróti, Gergely; Szőri, Milán; Nyilasi, Andrea; Rákhely, Gábor; Kovács, Kornél L.

    2012-01-01

    A highly conserved histidine-rich region with unknown function was recognized in the large subunit of [NiFe] hydrogenases. The HxHxxHxxHxH sequence occurs in most membrane-bound hydrogenases, but only two of these histidines are present in the cytoplasmic ones. Site-directed mutagenesis of the His-rich region of the T. roseopersicina membrane-attached Hyn hydrogenase disclosed that the enzyme activity was significantly affected only by the replacement of the His104 residue. Computational analysis of the hydrogen bond network in the large subunits indicated that the second histidine of this motif might be a component of a proton transfer pathway including Arg487, Asp103, His104 and Glu436. Substitutions of the conserved amino acids of the presumed transfer route impaired the activity of the Hyn hydrogenase. Western hybridization was applied to demonstrate that the cellular level of the mutant hydrogenases was similar to that of the wild type. Mostly based on theoretical modeling, few proton transfer pathways have already been suggested for [NiFe] hydrogenases. Our results propose an alternative route for proton transfer between the [NiFe] active center and the surface of the protein. A novel feature of this model is that this proton pathway is located on the opposite side of the large subunit relative to the position of the small subunit. This is the first study presenting a systematic analysis of an in silico predicted proton translocation pathway in [NiFe] hydrogenases by site-directed mutagenesis. PMID:22511957

  5. Rhizobium leguminosarum hupE encodes a nickel transporter required for hydrogenase activity.

    PubMed

    Brito, Belén; Prieto, Rosa-Isabel; Cabrera, Ezequiel; Mandrand-Berthelot, Marie-Andrée; Imperial, Juan; Ruiz-Argüeso, Tomás; Palacios, José-Manuel

    2010-02-01

    Synthesis of the hydrogen uptake (Hup) system in Rhizobium leguminosarum bv. viciae requires the function of an 18-gene cluster (hupSLCDEFGHIJK-hypABFCDEX). Among them, the hupE gene encodes a protein showing six transmembrane domains for which a potential role as a nickel permease has been proposed. In this paper, we further characterize the nickel transport capacity of HupE and that of the translated product of hupE2, a hydrogenase-unlinked gene identified in the R. leguminosarum genome. HupE2 is a potential membrane protein that shows 48% amino acid sequence identity with HupE. Expression of both genes in the Escherichia coli nikABCDE mutant strain HYD723 restored hydrogenase activity and nickel transport. However, nickel transport assays revealed that HupE and HupE2 displayed different levels of nickel uptake. Site-directed mutagenesis of histidine residues in HupE revealed two motifs (HX(5)DH and FHGX[AV]HGXE) that are required for HupE functionality. An R. leguminosarum double mutant, SPF22A (hupE hupE2), exhibited reduced levels of hydrogenase activity in free-living cells, and this phenotype was complemented by nickel supplementation. Low levels of symbiotic hydrogenase activity were also observed in SPF22A bacteroid cells from lentil (Lens culinaris L.) root nodules but not in pea (Pisum sativum L.) bacteroids. Moreover, heterologous expression of the R. leguminosarum hup system in bacteroid cells of Rhizobium tropici and Mesorhizobium loti displayed reduced levels of hydrogen uptake in the absence of hupE. These data support the role of R. leguminosarum HupE as a nickel permease required for hydrogen uptake under both free-living and symbiotic conditions.

  6. Hydrogen production by termite gut protists: characterization of iron hydrogenases of Parabasalian symbionts of the termite Coptotermes formosanus.

    PubMed

    Inoue, Jun-Ichi; Saita, Kanako; Kudo, Toshiaki; Ui, Sadaharu; Ohkuma, Moriya

    2007-10-01

    Cellulolytic flagellated protists in the guts of termites produce molecular hydrogen (H(2)) that is emitted by the termites; however, little is known about the physiology and biochemistry of H(2) production from cellulose in the gut symbiotic protists due to their formidable unculturability. In order to understand the molecular basis for H(2) production, we here identified two genes encoding proteins homologous to iron-only hydrogenases (Fe hydrogenases) in Pseudotrichonympha grassii, a large cellulolytic symbiont in the phylum Parabasalia, in the gut of the termite Coptotermes formosanus. The two Fe hydrogenases were phylogenetically distinct and had different N-terminal accessory domains. The long-form protein represented a phylogenetic lineage unique among eukaryotic Fe hydrogenases, whereas the short form was monophyletic with those of other parabasalids. Active recombinant enzyme forms of these two Fe hydrogenases were successfully obtained without the specific auxiliary maturases. Although they differed in their extent of specific activity and optimal pH, both enzymes preferentially catalyzed H(2) evolution rather than H(2) uptake. H(2) evolution, at least that associated with the short-form enzyme, was still active even under high hydrogen partial pressure. H(2) evolution activity was detected in the hydrogenosomal fraction of P. grassii cells; however, the vigorous H(2) uptake activity of the endosymbiotic bacteria compensated for the strong H(2) evolution activity of the host protists. The results suggest that termite gut symbionts are a rich reservoir of novel Fe hydrogenases whose properties are adapted to the gut environment and that the potential of H(2) production in termite guts has been largely underestimated.

  7. Hydrogenase/ferredoxin charge-transfer complexes: effect of hydrogenase mutations on the complex association.

    PubMed

    Long, Hai; King, Paul W; Ghirardi, Maria L; Kim, Kwiseon

    2009-04-23

    The [FeFe]-hydrogenases in the green alga Chlamydomonas reinhardtii utilize photogenerated electrons to reduce protons into hydrogen gas. The electrons are supplied from photosystem I and transferred to the [FeFe]-hydrogenase through specific hydrogenase-ferredoxin association. To understand how structural and kinetic factors control the association better, we used Brownian dynamics simulation methods to simulate the charge-transfer complex formation between both native and in silico mutants of the [FeFe]-hydrogenase HYDA2 and the [2Fe2S]-ferredoxin FDX1 from C. reinhardtii . The changes in binding free energy between different HYDA2 mutants and the native FDX1 were calculated by the free-energy perturbation method. Within the limits of our current models, we found that two HYDA2 mutations, T99K(H) and D102K(H), led to lower binding free energies and higher association rate with FDX1 and are thus promising targets for improving hydrogen production rates in engineered organisms. PMID:19317477

  8. Determination of Hydrogenase in Free-living Cultures of Rhizobium japonicum and Energy Efficiency of Soybean Nodules 1

    PubMed Central

    Lim, Soo T.

    1978-01-01

    A sensitive tritium exchange assay was applied to the Rhizobium system for measuring the expression of uptake hydrogenase in free-living cultures of Rhizobium japonicum. Hydrogenase was detected about 45 hours after inoculation of cultures maintained under microaerophilic conditions (about 0.1% O2). The tritium exchange assay was used to screen a variety of different strains of R. japonicum (including major production strains) with the findings that about 30% of the strains expressed hydrogenase activity with identical results being observed using an alternative assay based on uptake of H2. The relative efficiency of intact soybean nodules inoculated with 10 different rhizobial strains gave results identical to those obtained using free-living cultures. The tritium exchange assay provides an easy, quick, and accurate assessment of H2 uptake efficiency of intact nodules. PMID:16660568

  9. Genes and gene networks implicated in aggression related behaviour.

    PubMed

    Malki, Karim; Pain, Oliver; Du Rietz, Ebba; Tosto, Maria Grazia; Paya-Cano, Jose; Sandnabba, Kenneth N; de Boer, Sietse; Schalkwyk, Leonard C; Sluyter, Frans

    2014-10-01

    Aggressive behaviour is a major cause of mortality and morbidity. Despite of moderate heritability estimates, progress in identifying the genetic factors underlying aggressive behaviour has been limited. There are currently three genetic mouse models of high and low aggression created using selective breeding. This is the first study to offer a global transcriptomic characterization of the prefrontal cortex across all three genetic mouse models of aggression. A systems biology approach has been applied to transcriptomic data across the three pairs of selected inbred mouse strains (Turku Aggressive (TA) and Turku Non-Aggressive (TNA), Short Attack Latency (SAL) and Long Attack Latency (LAL) mice and North Carolina Aggressive (NC900) and North Carolina Non-Aggressive (NC100)), providing novel insight into the neurobiological mechanisms and genetics underlying aggression. First, weighted gene co-expression network analysis (WGCNA) was performed to identify modules of highly correlated genes associated with aggression. Probe sets belonging to gene modules uncovered by WGCNA were carried forward for network analysis using ingenuity pathway analysis (IPA). The RankProd non-parametric algorithm was then used to statistically evaluate expression differences across the genes belonging to modules significantly associated with aggression. IPA uncovered two pathways, involving NF-kB and MAPKs. The secondary RankProd analysis yielded 14 differentially expressed genes, some of which have previously been implicated in pathways associated with aggressive behaviour, such as Adrbk2. The results highlighted plausible candidate genes and gene networks implicated in aggression-related behaviour.

  10. Biomimetic assembly and activation of [FeFe]-hydrogenases.

    PubMed

    Berggren, G; Adamska, A; Lambertz, C; Simmons, T R; Esselborn, J; Atta, M; Gambarelli, S; Mouesca, J-M; Reijerse, E; Lubitz, W; Happe, T; Artero, V; Fontecave, M

    2013-07-01

    Hydrogenases are the most active molecular catalysts for hydrogen production and uptake, and could therefore facilitate the development of new types of fuel cell. In [FeFe]-hydrogenases, catalysis takes place at a unique di-iron centre (the [2Fe] subsite), which contains a bridging dithiolate ligand, three CO ligands and two CN(-) ligands. Through a complex multienzymatic biosynthetic process, this [2Fe] subsite is first assembled on a maturation enzyme, HydF, and then delivered to the apo-hydrogenase for activation. Synthetic chemistry has been used to prepare remarkably similar mimics of that subsite, but it has failed to reproduce the natural enzymatic activities thus far. Here we show that three synthetic mimics (containing different bridging dithiolate ligands) can be loaded onto bacterial Thermotoga maritima HydF and then transferred to apo-HydA1, one of the hydrogenases of Chlamydomonas reinhardtii algae. Full activation of HydA1 was achieved only when using the HydF hybrid protein containing the mimic with an azadithiolate bridge, confirming the presence of this ligand in the active site of native [FeFe]-hydrogenases. This is an example of controlled metalloenzyme activation using the combination of a specific protein scaffold and active-site synthetic analogues. This simple methodology provides both new mechanistic and structural insight into hydrogenase maturation and a unique tool for producing recombinant wild-type and variant [FeFe]-hydrogenases, with no requirement for the complete maturation machinery. PMID:23803769

  11. Hydrogenase in actinorhizal root nodules and root nodule homogenates.

    PubMed Central

    Benson, D R; Arp, D J; Burris, R H

    1980-01-01

    Hydrogenases were measured in intact actinorhizal root nodules and from disrupted nodules of Alnus glutinosa, Alnus rhombifolia, Alnus rubra, and Myrica pensylvanica. Whole nodules took up H2 in an O2-dependent reaction. Endophyte preparations oxidized H2 through the oxyhydrogen reaction, but rates were enhanced when hydrogen uptake was coupled to artificial electron acceptors. Oxygen inhibited artifical acceptor-dependent H2 uptake. The hydrogenase system from M. pensylvanica had a different pattern of coupling to various electron acceptors than the hydrogenase systems from the alders; only the bayberry system evolved H2 from reduced viologen dyes. PMID:6989799

  12. O2-stable membrane-bound [NiFe]hydrogenase from a newly isolated Citrobacter sp. S-77.

    PubMed

    Eguchi, Shigenobu; Yoon, Ki-Seok; Ogo, Seiji

    2012-11-01

    Hydrogenases are of great interest due to their potential use in H(2)-based technology. However, most hydrogenases are highly sensitive to O(2), which have been the major bottleneck in hydrogenase studies. Here we report an O(2)-stable membrane-bound [NiFe]hydrogenase (MBH) purified from a newly isolated strain, S-77. According to the 16S rRNA gene sequence and phylogenetic analysis of the strain S-77, it belongs to the genus of Citrobacter. In vitro experiments using the cytoplasmic membrane of strain S-77 suggested that a cytochrome b acts as the physiological electron acceptor of the MBH. The purified MBH was composed of a dimer of heterodimers, consisting of two distinct subunits with the molecular weights of 58.5 and 38.5 kDa. The enzyme showed a specific activity for H(2)-oxidation of 661 U/mg, which is 35-fold greater than that for H(2)-production of 18.7 U/mg. Notably, the MBH showed a remarkable O(2)-stability, maintaining almost 95% of its original activity even after incubation for 30 h in air at 4°C. These results suggest that the O(2)-stable MBH may play an important role in the H(2)-metabolic pathway under the aerobic conditions of Citrobacter sp. S-77. This is the first report of the purification and biochemical characterization of an O(2)-stable MBH from the genus of Citrobacter.

  13. Genetic analysis of the Hox hydrogenase in the cyanobacterium Synechocystis sp. PCC 6803 reveals subunit roles in association, assembly, maturation, and function.

    PubMed

    Eckert, Carrie; Boehm, Marko; Carrieri, Damian; Yu, Jianping; Dubini, Alexandra; Nixon, Peter J; Maness, Pin-Ching

    2012-12-21

    Hydrogenases are metalloenzymes that catalyze 2H(+) + 2e(-) ↔ H(2). A multisubunit, bidirectional [NiFe]-hydrogenase has been identified and characterized in a number of bacteria, including cyanobacteria, where it is hypothesized to function as an electron valve, balancing reductant in the cell. In cyanobacteria, this Hox hydrogenase consists of five proteins in two functional moieties: a hydrogenase moiety (HoxYH) with homology to heterodimeric [NiFe]-hydrogenases and a diaphorase moiety (HoxEFU) with homology to NuoEFG of respiratory Complex I, linking NAD(P)H ↔ NAD(P)(+) as a source/sink for electrons. Here, we present an extensive study of Hox hydrogenase in the cyanobacterium Synechocystis sp. PCC 6803. We identify the presence of HoxEFUYH, HoxFUYH, HoxEFU, HoxFU, and HoxYH subcomplexes as well as association of the immature, unprocessed large subunit (HoxH) with other Hox subunits and unidentified factors, providing a basis for understanding Hox maturation and assembly. The analysis of mutants containing individual and combined hox gene deletions in a common parental strain reveals apparent alterations in subunit abundance and highlights an essential role for HoxF and HoxU in complex/subcomplex association. In addition, analysis of individual and combined hox mutant phenotypes in a single strain background provides a clear view of the function of each subunit in hydrogenase activity and presents evidence that its physiological function is more complicated than previously reported, with no outward defects apparent in growth or photosynthesis under various growth conditions.

  14. Gene Transfers Between Distantly Related Organisms

    NASA Technical Reports Server (NTRS)

    Doolittle, Russell F.

    2003-01-01

    With the completion of numerous microbial genome sequences, reports of individual gene transfers between distantly related prokaryotes have become commonplace. On the other hand, transfers between prokaryotes and eukaryotes still excite the imagination. Many of these claims may be premature, but some are certainly valid. In this chapter, the kinds of supporting data needed to propose transfers between distantly related organisms and cite some interesting examples are considered.

  15. Biomimetic assembly and activation of [FeFe]-hydrogenases

    PubMed Central

    Berggren, G.; Esselborn, J.; Atta, M.; Gambarelli, S.; Mouesca, JM; Reijerse, E.; Lubitz, W.; Happe, T.; Artero, V.; Fontecave, M.

    2013-01-01

    Hydrogenases are the most active molecular catalysts for hydrogen production and uptake on earth1,2 and are thus extensively studied with respect to their technological exploitation as noble metal substitutes in (photo)electrolysers and fuel cells3-5. In [FeFe]-hydrogenases catalysis takes place at a unique diiron center (the [2Fe] subsite) featuring a bridging dithiolate ligand, as well as three CO and two CN− ligands (Figure 1)6,7. Through a complex and as yet poorly understood multienzymatic biosynthetic process, this [2Fe] subsite is first assembled onto a maturation enzyme, HydF. From there, it is delivered to the apo-hydrogenase for activation8. Synthetic chemistry has allowed the preparation of remarkably close mimics of that subsite1 but failed to reproduce the natural enzymatic activities so far. Here we show that three such synthetic mimics (with different bridging dithiolate ligands) can be loaded onto HydF and then transferred to apo-HydA1, one of the hydrogenases of Chlamydomonas reinhardtii. Remarkably, full activation of HydA1 was achieved exclusively using the HydF hybrid protein containing the mimic with an azadithiolate bridge, confirming the presence of this ligand in the active site of [FeFe]-hydrogenases9,10. This is the first example of controlled metalloenzyme activation using the combination of a specific protein scaffold and active site synthetic analogues. This simple methodology provides both new mechanistic and structural insight into hydrogenase maturation and a unique tool for producing recombinant wild-type and variant [FeFe]-hydrogenases, with no requirement for the complete maturation machinery. It opens the possibility to engineer the [FeFe]-hydrogenase active site through synthetic chemistry. PMID:23803769

  16. Exploring the microbially-mediated soil H2 sink: A lab-based study of the physiology and related H2 consumption of isolates from the Harvard Forest

    NASA Astrophysics Data System (ADS)

    Rao, D.; Meredith, L. K.; Bosak, T.; Hansel, C. M.; Ono, S.; Prinn, R. G.

    2012-12-01

    Atmospheric hydrogen (H2) is a secondary greenhouse gas because it attenuates the removal of methane (CH4) from the atmosphere. The largest and most uncertain term in the H2 biogeochemical cycle, microbe-mediated soil uptake, is responsible for about 80% of Earth's tropospheric H2 sink. Recently, the first H2-oxidizing soil microorganisms were discovered (genus Streptomyces) whose low-threshold, high-affinity NiFe-hydrogenase functions at ambient H2 levels (approx. 530 ppb). To better understand the ecological function of this hydrogenase, we conducted a controlled laboratory study of the H2 uptake behavior in accordance with the complex life cycle development of the streptomycetes. Several strains of the genus Streptomyces containing a high-affinity NiFe- hydrogenase were isolated from soil at the Harvard Forest. The presence of this hydrogenase, detected by PCR amplification of the hydrogenase large subunit, predicted H2 uptake behavior in wild-type streptomycetes and in phylogenetically different organisms containing more distantly related versions of the gene. H2 uptake depended on the streptomyces' life cycle, reaching a maximum during spore formation. These findings reveal connections between environmental conditions, organismal life cycle, and H2 uptake. With the rise of H2-based energy sources and a potential change in the tropospheric concentration of H2, understanding the sources and sinks of this trace gas is important for the future.

  17. Structure of an Actinobacterial-Type [NiFe]-Hydrogenase Reveals Insight into O2-Tolerant H2 Oxidation.

    PubMed

    Schäfer, Caspar; Bommer, Martin; Hennig, Sandra E; Jeoung, Jae-Hun; Dobbek, Holger; Lenz, Oliver

    2016-02-01

    A novel group of bacterial [NiFe]-hydrogenases is responsible for high-affinity H2 uptake from the troposphere, and is therefore thought to play an important role in the global H2 cycle. Here we present the first crystal structure at 2.85-Å resolution of such an actinobacterial-type hydrogenase (AH), which was isolated from the dihydrogen oxidizing bacterium, Ralstonia eutropha. The enzyme has a dimeric structure carrying two active [NiFe] sites that are interconnected by six [4Fe4S] clusters over a range of approximately 90 Å. Unlike most other [NiFe]-hydrogenases, the [4Fe4S] cluster proximal to the [NiFe] site is coordinated by three cysteines and one aspartate. Mutagenesis experiments revealed that this aspartate residue is related to the apparent O2 insensitivity of the AH. Our data provide first structural insight into specialized hydrogenases that are supposed to consume atmospheric H2 under challenging conditions, i.e. at high O2 concentration and wide temperature and pH ranges.

  18. Transcriptional and Mutational Analysis of the Uptake Hydrogenase of the Filamentous Cyanobacterium Anabaena variabilis ATCC 29413

    PubMed Central

    Happe, Thomas; Schütz, Kathrin; Böhme, Herbert

    2000-01-01

    A 10-kb DNA region of the cyanobacterium Anabaena variabilis ATCC 29413 containing the structural genes of the uptake hydrogenase (hupSL) was cloned and sequenced. In contrast to the hupL gene of Anabaena sp. strain PCC 7120, which is interrupted by a 10.5-kb DNA fragment in vegetative cells, there is no programmed rearrangement within the hupL gene during the heterocyst differentiation of A. variabilis. The hupSL genes were transcribed as a 2.7-kb operon and were induced only under nitrogen-fixing conditions, as shown by Northern blot experiments and reverse transcriptase PCR. Primer extension experiments with a fluorescence-labeled oligonucleotide primer confirmed these results and identified the 5′ start of the mRNA transcript 103 bp upstream of the ATG initiation codon. A consensus sequence in the promoter that is recognized by the fumarate nitrate reductase regulator (Fnr) could be detected. The hupSL operon in A. variabilis was interrupted by an interposon deletion (mutant strain AVM13). Under N2-fixing conditions, the mutant strain exhibited significantly increased rates in H2 accumulation and produced three times more hydrogen than the wild type. These results indicate that the uptake hydrogenase is catalytically active in the wild type and that the enzyme reoxidizes the H2 developed by the nitrogenase. The Nif phenotype of the mutant strain showed a slight decrease of acetylene reduction compared to that of the wild type. PMID:10692368

  19. Mediastinal paragangliomas related to SDHx gene mutations

    PubMed Central

    Ćwikła, Jarosław; Prejbisz, Aleksander; Kwiatek, Paweł; Szperl, Małgorzata; Michalski, Wojciech; Wyrwicz, Lucjan; Kuśmierczyk, Mariusz; Januszewicz, Andrzej; Maciejczyk, Anna; Roszczynko, Marta; Pęczkowska, Mariola

    2016-01-01

    Introduction Paragangliomas (PGLs) related to hereditary syndromes are rare mediastinal tumors. Paragangliomas are caused by mutations in genes encoding subunits of succinate dehydrogenase enzyme (SDH). Aim To evaluate clinical, anatomical and functional characteristics of mediastinal paragangliomas related to SDHx gene mutations. Material and methods Retrospective analysis of 75 patients with confirmed SDHx gene mutations (24 patients with SDHB, 5 SDHC, 46 with SDHD mutations) was performed. Patients underwent evaluation using computed tomography (CT), somatostatin receptor scintigraphy (SRS) (99mTc-[HYNIC,Tyr3]-octreotide), 123I mIBG scintigraphy and urinary excretion of total methoxycatecholamines. Results Out of 75 patients, 16 (21%) patients (1 SDHB, 15 SDHD mutations) had 17 PGLs localized in the mediastinum. Fourteen PGLs were localized in the middle mediastinum (intrapericardial) and 3 PGLs in the posterior mediastinum. The median diameter of paragangliomas measured on the axial slice was 24.3 mm (interquartile range (IQR): 14.7–36.6), and the median volume was 2.78 ml (IQR: 0.87–16.16). Twelve out of 16 patients (75%) underwent SRS, and 11 of them (92.3%) had pathological uptake of the radiotracer. Eleven (68.75%) out of 16 patients underwent 123 I mIBG, with only 3 positive results. Symptoms of catecholamine excretion were observed in 3 patients with PGLs localized in the posterior mediastinum. All PGLs were benign except in 1 patient with the SDHB mutation and PGL detected in the posterior mediastinum, who had a metastatic disease. Conclusions Most mediastinal paragangliomas were related to SDHD gene mutations. They were asymptomatic, localized in the medial mediastinum, intrapericardially. PMID:27785149

  20. [FeFe]-hydrogenase in Yellowstone National Park: evidence for dispersal limitation and phylogenetic niche conservatism.

    PubMed

    Boyd, Eric S; Hamilton, Trinity L; Spear, John R; Lavin, Matthew; Peters, John W

    2010-12-01

    Hydrogen (H₂) has an important role in the anaerobic degradation of organic carbon and is the basis for many syntrophic interactions that commonly occur in microbial communities. Little is known, however, with regard to the biotic and/or abiotic factors that control the distribution and phylogenetic diversity of organisms which produce H₂ in microbial communities. In this study, we examined the [FeFe]-hydrogenase gene (hydA) as a proxy for fermentative bacterial H₂ production along physical and chemical gradients in various geothermal springs in Yellowstone National Park (YNP), WY, USA. The distribution of hydA in YNP geothermal springs was constrained by pH to environments co-inhabited by oxygenic phototrophs and to environments predicted to have low inputs of abiotic H₂. The individual HydA asssemblages from YNP springs were more closely related when compared with randomly assembled communities, which suggests ecological filtering. Model selection approaches revealed that geographic distance was the best explanatory variable to predict the phylogenetic relatedness of HydA communities. This evinces the dispersal limitation imposed by the geothermal spring environment on HydA phylogenetic diversity even at small spatial scales. pH differences between sites is the second highest ranked explanatory variable of HydA phylogenetic relatedness, which suggests that the ecology related to pH imposes strong phylogenetic niche conservatism. Collectively, these results indicate that pH has imposed strong niche conservatism on fermentative bacteria and that, within a narrow pH realm, YNP springs are dispersal limited with respect to fermentative bacterial communities.

  1. Solar powered biohydrogen production requires specific localization of the hydrogenase

    DOE PAGESBeta

    Burroughs, Nigel J.; Boehm, Marko; Eckert, Carrie; Mastroianni, Giulia; Spence, Edward M.; Yu, Jianfeng; Nixon, Peter J.; Appel, Jens; Mullineaux, Conrad W.; Bryan, Samantha J.

    2014-09-04

    Cyanobacteria contain a bidirectional [NiFe] hydrogenase which transiently produces hydrogen upon exposure of anoxic cells to light, potentially acting as a “valve” releasing excess electrons from the electron transport chain. However, its interaction with the photosynthetic electron transport chain remains unclear. By GFP-tagging the HoxF diaphorase subunit we show that the hydrogenase is thylakoid associated, comprising a population dispersed uniformly through the thylakoids and a subpopulation localized to discrete puncta in the distal thylakoid. Thylakoid localisation of both the HoxH and HoxY hydrogenase subunits is confirmed by immunogold electron microscopy. The diaphorase HoxE subunit is essential for recruitment to themore » dispersed thylakoid population, potentially anchoring the hydrogenase to the membrane, but aggregation to puncta occurs through a distinct HoxE-independent mechanism. Membrane association does not require NDH-1. Localization is dynamic on a scale of minutes, with anoxia and high light inducing a significant redistribution between these populations in favour of puncta. Lastly, since HoxE is essential for access to its electron donor, electron supply to the hydrogenase depends on a physiologically controlled localization, potentially offering a new avenue to enhance photosynthetic hydrogen production by exploiting localization/aggregation signals.« less

  2. Solar powered biohydrogen production requires specific localization of the hydrogenase

    SciTech Connect

    Burroughs, Nigel J.; Boehm, Marko; Eckert, Carrie; Mastroianni, Giulia; Spence, Edward M.; Yu, Jianfeng; Nixon, Peter J.; Appel, Jens; Mullineaux, Conrad W.; Bryan, Samantha J.

    2014-09-04

    Cyanobacteria contain a bidirectional [NiFe] hydrogenase which transiently produces hydrogen upon exposure of anoxic cells to light, potentially acting as a “valve” releasing excess electrons from the electron transport chain. However, its interaction with the photosynthetic electron transport chain remains unclear. By GFP-tagging the HoxF diaphorase subunit we show that the hydrogenase is thylakoid associated, comprising a population dispersed uniformly through the thylakoids and a subpopulation localized to discrete puncta in the distal thylakoid. Thylakoid localisation of both the HoxH and HoxY hydrogenase subunits is confirmed by immunogold electron microscopy. The diaphorase HoxE subunit is essential for recruitment to the dispersed thylakoid population, potentially anchoring the hydrogenase to the membrane, but aggregation to puncta occurs through a distinct HoxE-independent mechanism. Membrane association does not require NDH-1. Localization is dynamic on a scale of minutes, with anoxia and high light inducing a significant redistribution between these populations in favour of puncta. Lastly, since HoxE is essential for access to its electron donor, electron supply to the hydrogenase depends on a physiologically controlled localization, potentially offering a new avenue to enhance photosynthetic hydrogen production by exploiting localization/aggregation signals.

  3. Physiological Reactions of the Reversible Hydrogenase from Anabaena 7120 1

    PubMed Central

    Houchins, Jeffrey P.; Burris, Robert H.

    1981-01-01

    The reversible hydrogenase from Anabaena 7120 appeared when O2 was continuously removed from a growing culture. Activity increased further when cells were incubated under argon in the dark or in the light plus 3-(3,4-dichlorophenyl)-1,1-dimethylurea. Hydrogenase existed in an inactive state during periods of O2 evolution. It could be reductively activated by exposure to reduced methyl viologen or by dark, anaerobic incubation. Hydrogenase-containing cells evolved H2 slowly during dark anaerobic incubations, and the rate of H2 evolution was increased by illumination with low intensity light. Light enhancement of H2 evolution was of short duration and was eliminated by the ferredoxin antagonist disalicylidene diaminopropane. Physiological acceptors that supported H2 uptake included NO3−, NO2−, and HSO3−, and light had a slight influence on the rate of H2 uptake with these acceptors. Low levels of O2 supported H2 uptake, but higher concentrations of O2 inactivated the hydrogenase. Hydrogen uptake with HCO3− as acceptor was the most rapid reaction measured, and it was strictly light-dependent. It occurred only at low light intensities, and higher light intensities restored normal O2-evolving photosynthesis. It is suggested that hydrogenase is present to capture exogenous H2 as a source of reducing equivalents during growth in anaerobic environments. PMID:16661986

  4. Hydrogen activation by [NiFe]-hydrogenases.

    PubMed

    Carr, Stephen B; Evans, Rhiannon M; Brooke, Emily J; Wehlin, Sara A M; Nomerotskaia, Elena; Sargent, Frank; Armstrong, Fraser A; Phillips, Simon E V

    2016-06-15

    Hydrogenase-1 (Hyd-1) from Escherichia coli is a membrane-bound enzyme that catalyses the reversible oxidation of molecular H2 The active site contains one Fe and one Ni atom and several conserved amino acids including an arginine (Arg(509)), which interacts with two conserved aspartate residues (Asp(118) and Asp(574)) forming an outer shell canopy over the metals. There is also a highly conserved glutamate (Glu(28)) positioned on the opposite side of the active site to the canopy. The mechanism of hydrogen activation has been dissected by site-directed mutagenesis to identify the catalytic base responsible for splitting molecular hydrogen and possible proton transfer pathways to/from the active site. Previous reported attempts to mutate residues in the canopy were unsuccessful, leading to an assumption of a purely structural role. Recent discoveries, however, suggest a catalytic requirement, for example replacing the arginine with lysine (R509K) leaves the structure virtually unchanged, but catalytic activity falls by more than 100-fold. Variants containing amino acid substitutions at either or both, aspartates retain significant activity. We now propose a new mechanism: heterolytic H2 cleavage is via a mechanism akin to that of a frustrated Lewis pair (FLP), where H2 is polarized by simultaneous binding to the metal(s) (the acid) and a nitrogen from Arg(509) (the base). PMID:27284053

  5. Metagenomic and PCR-Based Diversity Surveys of [FeFe]-Hydrogenases Combined with Isolation of Alkaliphilic Hydrogen-Producing Bacteria from the Serpentinite-Hosted Prony Hydrothermal Field, New Caledonia.

    PubMed

    Mei, Nan; Postec, Anne; Monnin, Christophe; Pelletier, Bernard; Payri, Claude E; Ménez, Bénédicte; Frouin, Eléonore; Ollivier, Bernard; Erauso, Gaël; Quéméneur, Marianne

    2016-01-01

    High amounts of hydrogen are emitted in the serpentinite-hosted hydrothermal field of the Prony Bay (PHF, New Caledonia), where high-pH (~11), low-temperature (< 40°C), and low-salinity fluids are discharged in both intertidal and shallow submarine environments. In this study, we investigated the diversity and distribution of potentially hydrogen-producing bacteria in Prony hyperalkaline springs by using metagenomic analyses and different PCR-amplified DNA sequencing methods. The retrieved sequences of hydA genes, encoding the catalytic subunit of [FeFe]-hydrogenases and, used as a molecular marker of hydrogen-producing bacteria, were mainly related to those of Firmicutes and clustered into two distinct groups depending on sampling locations. Intertidal samples were dominated by new hydA sequences related to uncultured Firmicutes retrieved from paddy soils, while submarine samples were dominated by diverse hydA sequences affiliated with anaerobic and/or thermophilic submarine Firmicutes pertaining to the orders Thermoanaerobacterales or Clostridiales. The novelty and diversity of these [FeFe]-hydrogenases may reflect the unique environmental conditions prevailing in the PHF (i.e., high-pH, low-salt, mesothermic fluids). In addition, novel alkaliphilic hydrogen-producing Firmicutes (Clostridiales and Bacillales) were successfully isolated from both intertidal and submarine PHF chimney samples. Both molecular and cultivation-based data demonstrated the ability of Firmicutes originating from serpentinite-hosted environments to produce hydrogen by fermentation, potentially contributing to the molecular hydrogen balance in situ. PMID:27625634

  6. Metagenomic and PCR-Based Diversity Surveys of [FeFe]-Hydrogenases Combined with Isolation of Alkaliphilic Hydrogen-Producing Bacteria from the Serpentinite-Hosted Prony Hydrothermal Field, New Caledonia

    PubMed Central

    Mei, Nan; Postec, Anne; Monnin, Christophe; Pelletier, Bernard; Payri, Claude E.; Ménez, Bénédicte; Frouin, Eléonore; Ollivier, Bernard; Erauso, Gaël; Quéméneur, Marianne

    2016-01-01

    High amounts of hydrogen are emitted in the serpentinite-hosted hydrothermal field of the Prony Bay (PHF, New Caledonia), where high-pH (~11), low-temperature (< 40°C), and low-salinity fluids are discharged in both intertidal and shallow submarine environments. In this study, we investigated the diversity and distribution of potentially hydrogen-producing bacteria in Prony hyperalkaline springs by using metagenomic analyses and different PCR-amplified DNA sequencing methods. The retrieved sequences of hydA genes, encoding the catalytic subunit of [FeFe]-hydrogenases and, used as a molecular marker of hydrogen-producing bacteria, were mainly related to those of Firmicutes and clustered into two distinct groups depending on sampling locations. Intertidal samples were dominated by new hydA sequences related to uncultured Firmicutes retrieved from paddy soils, while submarine samples were dominated by diverse hydA sequences affiliated with anaerobic and/or thermophilic submarine Firmicutes pertaining to the orders Thermoanaerobacterales or Clostridiales. The novelty and diversity of these [FeFe]-hydrogenases may reflect the unique environmental conditions prevailing in the PHF (i.e., high-pH, low-salt, mesothermic fluids). In addition, novel alkaliphilic hydrogen-producing Firmicutes (Clostridiales and Bacillales) were successfully isolated from both intertidal and submarine PHF chimney samples. Both molecular and cultivation-based data demonstrated the ability of Firmicutes originating from serpentinite-hosted environments to produce hydrogen by fermentation, potentially contributing to the molecular hydrogen balance in situ.

  7. Metagenomic and PCR-Based Diversity Surveys of [FeFe]-Hydrogenases Combined with Isolation of Alkaliphilic Hydrogen-Producing Bacteria from the Serpentinite-Hosted Prony Hydrothermal Field, New Caledonia

    PubMed Central

    Mei, Nan; Postec, Anne; Monnin, Christophe; Pelletier, Bernard; Payri, Claude E.; Ménez, Bénédicte; Frouin, Eléonore; Ollivier, Bernard; Erauso, Gaël; Quéméneur, Marianne

    2016-01-01

    High amounts of hydrogen are emitted in the serpentinite-hosted hydrothermal field of the Prony Bay (PHF, New Caledonia), where high-pH (~11), low-temperature (< 40°C), and low-salinity fluids are discharged in both intertidal and shallow submarine environments. In this study, we investigated the diversity and distribution of potentially hydrogen-producing bacteria in Prony hyperalkaline springs by using metagenomic analyses and different PCR-amplified DNA sequencing methods. The retrieved sequences of hydA genes, encoding the catalytic subunit of [FeFe]-hydrogenases and, used as a molecular marker of hydrogen-producing bacteria, were mainly related to those of Firmicutes and clustered into two distinct groups depending on sampling locations. Intertidal samples were dominated by new hydA sequences related to uncultured Firmicutes retrieved from paddy soils, while submarine samples were dominated by diverse hydA sequences affiliated with anaerobic and/or thermophilic submarine Firmicutes pertaining to the orders Thermoanaerobacterales or Clostridiales. The novelty and diversity of these [FeFe]-hydrogenases may reflect the unique environmental conditions prevailing in the PHF (i.e., high-pH, low-salt, mesothermic fluids). In addition, novel alkaliphilic hydrogen-producing Firmicutes (Clostridiales and Bacillales) were successfully isolated from both intertidal and submarine PHF chimney samples. Both molecular and cultivation-based data demonstrated the ability of Firmicutes originating from serpentinite-hosted environments to produce hydrogen by fermentation, potentially contributing to the molecular hydrogen balance in situ. PMID:27625634

  8. Recombinant antibodies for specific detection of clostridial [Fe-Fe] hydrogenases

    PubMed Central

    Mangayil, Rahul; Karp, Matti; Lamminmäki, Urpo; Santala, Ville

    2016-01-01

    Biological hydrogen production is based on activity of specific enzymes called hydrogenases. Hydrogenases are oxygen sensitive metalloenzymes containing Ni and/or Fe atoms at the active site, catalyzing reversible reduction of protons. Generally, [Fe-Fe] hydrogenases prefer proton reduction to molecular hydrogen, a potential energy carrier molecule that can be produced by bioprocesses in sustainable manner. Thus, monitoring tools have been developed to study the relationship between [Fe-Fe] hydrogenases and biohydrogen production in bioreactors at DNA and RNA levels. In the present study, novel molecular tools are introduced for quantitative monitoring of clostridial [Fe-Fe] hydrogenases at the protein level. Aerobic and anaerobic biopanning (for inactive and active [Fe-Fe] hydrogenase, respectively) of phage displayed single-chain variable fragment (scFv) antibody libraries aided in isolating nine potential scFvs. The enriched antibodies demonstrated high specificity towards Clostridium spp. [Fe-Fe] hydrogenases allowing detection from pure and mixed cultures. Additionally, the antibodies showed different binding characteristics towards hydrogenase catalytic states, providing a possible means for functional detection of clostridial [Fe-Fe] hydrogenases. From hydrogenase-antibody interaction studies we observed that though antibody binding reduced the enzyme catalytic activity, it facilitated to retain hydrogen evolution from oxygen exposed hydrogenases. PMID:27786270

  9. Distribution and activity of hydrogenase enzymes in subsurface sediments

    NASA Astrophysics Data System (ADS)

    Adhikari, R.; Nickel, J.; Glombitza, C.; Spivack, A. J.; D'Hondt, S. L.; Kallmeyer, J.

    2013-12-01

    Metabolically active microbial communities are present in a wide range of subsurface environments. Techniques like enumeration of microbial cells, activity measurements with radiotracer assays and the analysis of porewater constituents are currently being used to explore the subsurface biosphere, alongside with molecular biological analyses. However, many of these techniques reach their detection limits due to low microbial activity and abundance. Direct measurements of microbial turnover not just face issues of insufficient sensitivity, they only provide information about a single specific process rather than an overall microbial activity. Since hydrogenase enzymes are intracellular and ubiquitous in subsurface microbial communities, the enzyme activity represents a measure of total activity of the entire microbial community. A hydrogenase activity assay could quantify total metabolic activity without having to identify specific processes. This would be a major advantage in subsurface biosphere studies, where several metabolic processes can occur simultaneously. We quantified hydrogenase enzyme activity and distribution in sediment samples from different aquatic subsurface environments (Lake Van, Barents Sea, Equatorial Pacific and Gulf of Mexico) using a tritium-based assay. We found enzyme activity at all sites and depths. Volumetric hydrogenase activity did not show much variability between sites and sampling depths, whereas cell-specific activity ranged from 10-5 to 1 nmol H2 cell-1 d-1. Activity was lowest in sediment layers where nitrate was detected. Higher activity was associated with samples in which sulfate was the predominant electron acceptor. We found highest activity in samples from environments with >10 ppm methane in the pore water. The results show that cell-specific hydrogenase enzyme activity increases with decreasing energy yield of the electron acceptor used. It is not possible to convert volumetric or cell-specific hydrogenase activity into a

  10. Calcitonin Gene-Related Peptide (CGRP)

    PubMed Central

    Russo, Andrew F.

    2015-01-01

    Migraine is a neurological disorder that manifests as a debilitating headache associated with altered sensory perception. The neuropeptide calcitonin gene-related peptide (CGRP) is now firmly established as a key player in migraine. Clinical trials carried out during the past decade have proved that CGRP receptor antagonists are effective for treating migraine, and antibodies to the receptor and CGRP are currently under investigation. Despite this progress in the clinical arena, the mechanisms by which CGRP triggers migraine remain uncertain. This review discusses mechanisms whereby CGRP enhances sensitivity to sensory input at multiple levels in both the periphery and central nervous system. Future studies on epistatic and epigenetic regulators of CGRP actions are expected to shed further light on CGRP actions in migraine. In conclusion, targeting CGRP represents an approachable therapeutic strategy for migraine. PMID:25340934

  11. Genome Data Mining and Soil Survey for the Novel Group 5 [NiFe]-Hydrogenase To Explore the Diversity and Ecological Importance of Presumptive High-Affinity H2-Oxidizing Bacteria ▿†

    PubMed Central

    Constant, Philippe; Chowdhury, Soumitra Paul; Hesse, Laura; Pratscher, Jennifer; Conrad, Ralf

    2011-01-01

    Streptomyces soil isolates exhibiting the unique ability to oxidize atmospheric H2 possess genes specifying a putative high-affinity [NiFe]-hydrogenase. This study was undertaken to explore the taxonomic diversity and the ecological importance of this novel functional group. We propose to designate the genes encoding the small and large subunits of the putative high-affinity hydrogenase hhyS and hhyL, respectively. Genome data mining revealed that the hhyL gene is unevenly distributed in the phyla Actinobacteria, Proteobacteria, Chloroflexi, and Acidobacteria. The hhyL gene sequences comprised a phylogenetically distinct group, namely, the group 5 [NiFe]-hydrogenase genes. The presumptive high-affinity H2-oxidizing bacteria constituting group 5 were shown to possess a hydrogenase gene cluster, including the genes encoding auxiliary and structural components of the enzyme and four additional open reading frames (ORFs) of unknown function. A soil survey confirmed that both high-affinity H2 oxidation activity and the hhyL gene are ubiquitous. A quantitative PCR assay revealed that soil contained 106 to 108 hhyL gene copies g (dry weight)−1. Assuming one hhyL gene copy per genome, the abundance of presumptive high-affinity H2-oxidizing bacteria was higher than the maximal population size for which maintenance energy requirements would be fully supplied through the H2 oxidation activity measured in soil. Our data indicate that the abundance of the hhyL gene should not be taken as a reliable proxy for the uptake of atmospheric H2 by soil, because high-affinity H2 oxidation is a facultatively mixotrophic metabolism, and microorganisms harboring a nonfunctional group 5 [NiFe]-hydrogenase may occur. PMID:21742924

  12. Purification and properties of the membrane-bound by hydrogenase from Desulfovibrio desulfuricans.

    PubMed

    Lalla-Maharajh, W V; Hall, D O; Cammack, R; Rao, K K; Le Gall, J

    1983-02-01

    The membrane-bound hydrogenase from the anaerobic sulphate-reducing bacterium Desulfovibrio desulfuricans (Norway strain) has been purified to homogeneity, with an overall 80-fold purification and a specific activity of 70 mumol of H2 evolved/min per mg of protein. The hydrogenase had a relative molecular mass of 58 000 as determined by gel filtration and was estimated to contain six iron atoms and six acid-labile sulphur groups per molecule. The absorption spectrum of the enzyme was characteristic of an iron-sulphur protein. The E400 and E280 were 28 500 and 109 000 M-1.cm-1 respectively. The e.s.r. of the oxidized protein indicated the presence of [4Fe-4S]3+ or [3Fe-3S]3+, and another paramagnetic centre, probably Ni(III). The hydrogenase was inhibited by heavy-metal salts, carbon monoxide and high ionic strength. However, it was resistant to inhibition by thiol-blocking and metal-complexing reagents. N-Bromosuccinimide totally inhibited the enzyme activity at low concentrations. The enzyme was stable to O2 over long periods and to high temperatures. It catalyses both H2-evolution and H2-uptake with a variety of artificial electron carriers. D. desulfuricans cytochrome C3, its natural electron carrier, had a high affinity for the enzyme (Km = 2 microns). Rate enhancement was observed when cytochrome C3 was added to Methyl Viologen in the H2-evolution assay. The pH optimum for H2-evolution was 6.5. PMID:6303306

  13. From enzyme maturation to synthetic chemistry: the case of hydrogenases.

    PubMed

    Artero, Vincent; Berggren, Gustav; Atta, Mohamed; Caserta, Giorgio; Roy, Souvik; Pecqueur, Ludovic; Fontecave, Marc

    2015-08-18

    Water splitting into oxygen and hydrogen is one of the most attractive strategies for storing solar energy and electricity. Because the processes at work are multielectronic, there is a crucial need for efficient and stable catalysts, which in addition have to be cheap for future industrial developments (electrolyzers, photoelectrochemicals, and fuel cells). Specifically for the water/hydrogen interconversion, Nature is an exquisite source of inspiration since this chemistry contributes to the bioenergetic metabolism of a number of living organisms via the activity of fascinating metalloenzymes, the hydrogenases. In this Account, we first briefly describe the structure of the unique dinuclear organometallic active sites of the two classes of hydrogenases as well as the complex protein machineries involved in their biosynthesis, their so-called maturation processes. This knowledge allows for the development of a fruitful bioinspired chemistry approach, which has already led to a number of interesting and original catalysts mimicking the natural active sites. More specifically, we describe our own attempts to prepare artificial hydrogenases. This can be achieved via the standard bioinspired approach using the combination of a synthetic bioinspired catalyst and a polypeptide scaffold. Such hybrid complexes provide the opportunity to optimize the system by manipulating both the catalyst through chemical synthesis and the protein component through mutagenesis. We also raise the possibility to reach such artificial systems via an original strategy based on mimicking the enzyme maturation pathways. This is illustrated in this Account by two examples developed in our laboratory. First, we show how the preparation of a lysozyme-{Mn(I)(CO)3} hybrid and its clean reaction with a nickel complex led us to generate a new class of binuclear Ni-Mn H2-evolving catalysts mimicking the active site of [NiFe]-hydrogenases. Then we describe how we were able to rationally design and

  14. Nucleotide sequences and genetic analysis of hydrogen oxidation (hox) genes in Azotobacter vinelandii.

    PubMed Central

    Menon, A L; Mortenson, L E; Robson, R L

    1992-01-01

    Azotobacter vinelandii contains a heterodimeric, membrane-bound [NiFe]hydrogenase capable of catalyzing the reversible oxidation of H2. The beta and alpha subunits of the enzyme are encoded by the structural genes hoxK and hoxG, respectively, which appear to form part of an operon that contains at least one further potential gene (open reading frame 3 [ORF3]). In this study, determination of the nucleotide sequence of a region of 2,344 bp downstream of ORF3 revealed four additional closely spaced or overlapping ORFs. These ORFs, ORF4 through ORF7, potentially encode polypeptides with predicted masses of 22.8, 11.4, 16.3, and 31 kDa, respectively. Mutagenesis of the chromosome of A. vinelandii in the area sequenced was carried out by introduction of antibiotic resistance gene cassettes. Disruption of hoxK and hoxG by a kanamycin resistance gene abolished whole-cell hydrogenase activity coupled to O2 and led to loss of the hydrogenase alpha subunit. Insertional mutagenesis of ORF3 through ORF7 with a promoterless lacZ-Kmr cassette established that the region is transcriptionally active and involved in H2 oxidation. We propose to call ORF3 through ORF7 hoxZ, hoxM, hoxL, hoxO, and hoxQ, respectively. The predicted hox gene products resemble those encoded by genes from hydrogenase-related operons in other bacteria, including Escherichia coli and Alcaligenes eutrophus. Images PMID:1624446

  15. Enhanced Oxygen-Tolerance of the Full Heterotrimeric Membrane-Bound [NiFe]-Hydrogenase of Ralstonia eutropha

    PubMed Central

    2014-01-01

    Hydrogenases are oxygen-sensitive enzymes that catalyze the conversion between protons and hydrogen. Water-soluble subcomplexes of membrane-bound [NiFe]-hydrogenases (MBH) have been extensively studied for applications in hydrogen–oxygen fuel cells as they are relatively tolerant to oxygen, although even these catalysts are still inactivated in oxidative conditions. Here, the full heterotrimeric MBH of Ralstonia eutropha, including the membrane-integral cytochrome b subunit, was investigated electrochemically using electrodes modified with planar tethered bilayer lipid membranes (tBLM). Cyclic voltammetry and chronoamperometry experiments show that MBH, in equilibrium with the quinone pool in the tBLM, does not anaerobically inactivate under oxidative redox conditions. In aerobic environments, the MBH is reversibly inactivated by O2, but reactivation was found to be fast even under oxidative redox conditions. This enhanced resistance to inactivation is ascribed to the oligomeric state of MBH in the lipid membrane. PMID:24866391

  16. Production and Engineering of Hydrogenase as a Biocatalyst for Hydrogen Fuel

    SciTech Connect

    Wang, Guangyi

    2010-04-09

    Hydrogenases are fascinating redox proteins, showing tremendous promise in the utilization of hydrogen fuel as a bioelectrocatalyst. They play critical roles in both biohydrogen production and hydrogen oxidation. Specifically, the recently-established comparability of the oxidative activity of the [NiFe]-hydrogenase active site to that of the fuel cell catalyst platinum marks a significant milestone for the potential application of hydrogenase in hydrogen fuel cells to replace platinum. However, the ability of producing hydrogenase in heterologous expression hosts and the sensitivity of hydrogenases to oxygen and carbon monoxide, etc. have seriously limited the viable macroscale utilization and production of hydrogen from the renewable source. A new technology for the production of up-take hydrogenase is being developed for the utilization of hydrogenase as a hydrogen catalyst. The development of this new technology integrates knowledge of structural biology, molecular biology, and principles of metabolic engineering to produce and engineer a stable hydrogenase as a hydrogen bioelectrocatalyst. It contributes to the critical issues of “expensive noble metal catalysts (i.e., platinum) and their limited reserves threatening the long-term sustainability of a hydrogen economy”. It also provides a model to “design natural materials and enzyme catalyst” for “efficient and cost-effective technologies” for a clean and sustainable energy in 21st century. This new technology includes 3 major components. The first component is the synthetic operons, which carry hydrogenase maturation pathways of Ralstonia eutropha. These synthetic operons are engineered to produce RH hydrogenase in the Escherichia coli strains based on our current molecular and genetic information of hydrogenase maturation mechanisms and pathways of R. eutropha. It presents the first example of producing hydrogenase in the conventional expression host using synthetic biology principles and tool

  17. Photosensitivity of the Ni-A state of [NiFe] hydrogenase from Desulfovibrio vulgaris Miyazaki F with visible light

    SciTech Connect

    Osuka, Hisao; Shomura, Yasuhito; Komori, Hirofumi; Shibata, Naoki; Nagao, Satoshi; Higuchi, Yoshiki; Hirota, Shun

    2013-01-04

    Highlights: Black-Right-Pointing-Pointer Ni-A state of [NiFe] hydrogenase showed light sensitivity. Black-Right-Pointing-Pointer New FT-IR bands were observed with light irradiation of the Ni-A state. Black-Right-Pointing-Pointer EPR g-values of the Ni-A state shifted upon light irradiation. Black-Right-Pointing-Pointer The light-induced state converted back to the Ni-A state under the dark condition. -- Abstract: [NiFe] hydrogenase catalyzes reversible oxidation of molecular hydrogen. Its active site is constructed of a hetero dinuclear Ni-Fe complex, and the oxidation state of the Ni ion changes according to the redox state of the enzyme. We found that the Ni-A state (an inactive unready, oxidized state) of [NiFe] hydrogenase from Desulfovibrio vulgaris Miyazaki F (DvMF) is light sensitive and forms a new state (Ni-AL) with irradiation of visible light. The Fourier transform infrared (FT-IR) bands at 1956, 2084 and 2094 cm{sup -1} of the Ni-A state shifted to 1971, 2086 and 2098 cm{sup -1} in the Ni-AL state. The g-values of g{sub x} = 2.30, g{sub y} = 2.23 and g{sub z} = 2.01 for the signals in the electron paramagnetic resonance (EPR) spectrum of the Ni-A state at room temperature varied for -0.009, +0.012 and +0.010, respectively, upon light irradiation. The light-induced Ni-AL state converted back immediately to the Ni-A state under dark condition at room temperature. These results show that the coordination structure of the Fe site of the Ni-A state of [NiFe] hydrogenase is perturbed significantly by light irradiation with relatively small coordination change at the Ni site.

  18. Structure and function of photosystem I–[FeFe] hydrogenase protein fusions: An all-atom molecular dynamics study

    SciTech Connect

    Harris, Bradley J.; Cheng, Xiaolin; Frymier, Paul

    2015-12-15

    All-atom molecular dynamics (MD) simulation was used to study the solution dynamics and protein protein interactions of protein fusions of photosystem I (PSI) from Thermosynechococcus elongatus and an [FeFe]-hydrogenase (FeFe H2ase) from Clostridium pasteurianum, a unique complex capable of photocatalytic hydrogen production. This study involved fusions of these two proteins via dithiol linkers of different length including decanedithiol, octanedithiol, and hexanedithiol, for which experimental data had previously been obtained. Evaluation of root-mean-squared deviations (RMSDs) relative to the respective crystal structures of PSI and the FeFe H2ase shows that these fusion complexes approach stable equilibrium conformations during the MD simulations. Investigating protein mobility via root-mean-squared fluctuations (RMSFs) reveals that tethering via the shortest hexanedithiol linker results in increased atomic fluctuations of both PSI and the hydrogenase in these fusion complexes. Furthermore, evaluation of the inter- and intraprotein electron transfer distances in these fusion complexes indicates that the structural changes in the FeFe H2ase arising from ligation to PSI via the shortest hexanedithiol linker may hinder electron transport in the hydrogenase, thus providing a molecular level explanation for the observation that the medium-length octanedithiol linker gives the highest hydrogen production rate.

  19. Structure and function of photosystem I–[FeFe] hydrogenase protein fusions: An all-atom molecular dynamics study

    DOE PAGESBeta

    Harris, Bradley J.; Cheng, Xiaolin; Frymier, Paul

    2015-12-15

    All-atom molecular dynamics (MD) simulation was used to study the solution dynamics and protein protein interactions of protein fusions of photosystem I (PSI) from Thermosynechococcus elongatus and an [FeFe]-hydrogenase (FeFe H2ase) from Clostridium pasteurianum, a unique complex capable of photocatalytic hydrogen production. This study involved fusions of these two proteins via dithiol linkers of different length including decanedithiol, octanedithiol, and hexanedithiol, for which experimental data had previously been obtained. Evaluation of root-mean-squared deviations (RMSDs) relative to the respective crystal structures of PSI and the FeFe H2ase shows that these fusion complexes approach stable equilibrium conformations during the MD simulations. Investigatingmore » protein mobility via root-mean-squared fluctuations (RMSFs) reveals that tethering via the shortest hexanedithiol linker results in increased atomic fluctuations of both PSI and the hydrogenase in these fusion complexes. Furthermore, evaluation of the inter- and intraprotein electron transfer distances in these fusion complexes indicates that the structural changes in the FeFe H2ase arising from ligation to PSI via the shortest hexanedithiol linker may hinder electron transport in the hydrogenase, thus providing a molecular level explanation for the observation that the medium-length octanedithiol linker gives the highest hydrogen production rate.« less

  20. Hydrogenase activity in aged, nonviable Desulfovibrio vulgaris cultures and its significance in anaerobic biocorrosion.

    PubMed

    Chatelus, C; Carrier, P; Saignes, P; Libert, M F; Berlier, Y; Lespinat, P A; Fauque, G; Legall, J

    1987-07-01

    Batch cultures of Desulfovibrio vulgaris stored at 32 degrees C for 10 months have been found to retain 50% of the hydrogenase activity of a 1-day culture. The hydrogenase found in old cultures needs reducing conditions for its activation. Viable cell counts are negative after 6 months, showing that the hydrogenase activity does not depend on the presence of viable cells. These observations are of importance in the understanding of anaerobic biocorrosion of metals caused by depolarization phenomena.

  1. Electrochemistry of Simple Organometallic Models of Iron-Iron Hydrogenases in Organic Solvent and Water.

    PubMed

    Gloaguen, Frederic

    2016-01-19

    Synthetic models of the active site of iron-iron hydrogenases are currently the subjects of numerous studies aimed at developing H2-production catalysts based on cheap and abundant materials. In this context, the present report offers an electrochemist's view of the catalysis of proton reduction by simple binuclear iron(I) thiolate complexes. Although these complexes probably do not follow a biocatalytic pathway, we analyze and discuss the interplay between the reduction potential and basicity and how these antagonist properties impact the mechanisms of proton-coupled electron transfer to the metal centers. This question is central to any consideration of the activity at the molecular level of hydrogenases and related enzymes. In a second part, special attention is paid to iron thiolate complexes holding rigid and unsaturated bridging ligands. The complexes that enjoy mild reduction potentials and stabilized reduced forms are promising iron-based catalysts for the photodriven evolution of H2 in organic solvents and, more importantly, in water.

  2. Spontaneous activation of [FeFe]-hydrogenases by an inorganic [2Fe] active site mimic

    PubMed Central

    Esselborn, Julian; Berggren, Gustav; Noth, Jens; Siebel, Judith; Hemschemeier, Anja; Artero, Vincent; Reijerse, Edward; Fontecave, Marc; Lubitz, Wolfgang; Happe, Thomas

    2013-01-01

    Hydrogenases catalyze the formation of hydrogen. The cofactor (H-cluster) of [FeFe]-hydrogenases consists of a [4Fe-4S]-cluster bridged to a unique [2Fe]-subcluster whose biosynthesis in vivo requires hydrogenase-specific maturases. Here we show that a chemical mimic of the [2Fe]-subcluster can reconstitute apo-hydrogenase to full activity, independent of helper proteins. The assembled H-cluster is virtually indistinguishable from the native cofactor. This procedure will be a powerful tool for developing novel artificial H2-producing catalysts. PMID:23934246

  3. Implementation of photobiological H2 production: the O 2 sensitivity of hydrogenases.

    PubMed

    Ghirardi, Maria L

    2015-09-01

    The search for the ultimate carbon-free fuel has intensified in recent years, with a major focus on photoproduction of H2. Biological sources of H2 include oxygenic photosynthetic green algae and cyanobacteria, both of which contain hydrogenase enzymes. Although algal and cyanobacterial hydrogenases perform the same enzymatic reaction through metallo-clusters, their hydrogenases have evolved separately, are expressed differently (transcription of algal hydrogenases is anaerobically induced, while bacterial hydrogenases are constitutively expressed), and display different sensitivity to O2 inactivation. Among various physiological factors, the sensitivity of hydrogenases to O2 has been one of the major factors preventing implementation of biological systems for commercial production of renewable H2. This review addresses recent strategies aimed at engineering increased O2 tolerance into hydrogenases (as of now mainly unsuccessful), as well as towards the development of methods to bypass the O2 sensitivity of hydrogenases (successful but still yielding low solar conversion efficiencies). The author concludes with a description of current approaches from various laboratories to incorporate multiple genetic traits into either algae or cyanobacteria to jointly address limiting factors other than the hydrogenase O2 sensitivity and achieve more sustained H2 photoproduction activity.

  4. Oxygen-resistant hydrogenases and methods for designing and making same

    DOEpatents

    King, Paul; Ghirardi, Maria Lucia; Seibert, Michael

    2014-03-04

    The invention provides oxygen-resistant iron-hydrogenases ([Fe]-hydrogenases) for use in the production of H.sub.2. Methods used in the design and engineering of the oxygen-resistant [Fe]-hydrogenases are disclosed, as are the methods of transforming and culturing appropriate host cells with the oxygen-resistant [Fe]-hydrogenases. Finally, the invention provides methods for utilizing the transformed, oxygen insensitive, host cells in the bulk production of H.sub.2 in a light catalyzed reaction having water as the reactant.

  5. Oxygen-resistant hydrogenases and methods for designing and making same

    DOEpatents

    King, Paul; Ghirardi, Maria L; Seibert, Michael

    2009-03-10

    The invention provides oxygen- resistant iron-hydrogenases ([Fe]-hydrogenases) for use in the production of H2. Methods used in the design and engineering of the oxygen-resistant [Fe]-hydrogenases are disclosed, as are the methods of transforming and culturing appropriate host cells with the oxygen-resistant [Fe]-hydrogenases. Finally, the invention provides methods for utilizing the transformed, oxygen insensitive, host cells in the bulk production of H.sub.2 in a light catalyzed reaction having water as the reactant.

  6. Overproduction of the membrane-bound [NiFe]-hydrogenase in Thermococcus kodakarensis and its effect on hydrogen production

    PubMed Central

    Kanai, Tamotsu; Simons, Jan-Robert; Tsukamoto, Ryohei; Nakajima, Akihito; Omori, Yoshiyuki; Matsuoka, Ryoji; Beppu, Haruki; Imanaka, Tadayuki; Atomi, Haruyuki

    2015-01-01

    The hyperthermophilic archaeon Thermococcus kodakarensis can utilize sugars or pyruvate for growth. In the absence of elemental sulfur, the electrons via oxidation of these substrates are accepted by protons, generating molecular hydrogen (H2). The hydrogenase responsible for this reaction is a membrane-bound [NiFe]-hydrogenase (Mbh). In this study, we have examined several possibilities to increase the protein levels of Mbh in T. kodakarensis by genetic engineering. Highest levels of intracellular Mbh levels were achieved when the promoter of the entire mbh operon (TK2080-TK2093) was exchanged to a strong constitutive promoter from the glutamate dehydrogenase gene (TK1431) (strain MHG1). When MHG1 was cultivated under continuous culture conditions using pyruvate-based medium, a nearly 25% higher specific hydrogen production rate (SHPR) of 35.3 mmol H2 g-dcw−1 h−1 was observed at a dilution rate of 0.31 h−1. We also combined mbh overexpression using an even stronger constitutive promoter from the cell surface glycoprotein gene (TK0895) with disruption of the genes encoding the cytosolic hydrogenase (Hyh) and an alanine aminotransferase (AlaAT), both of which are involved in hydrogen consumption (strain MAH1). At a dilution rate of 0.30 h−1, the SHPR was 36.2 mmol H2 g-dcw−1 h−1, corresponding to a 28% increase compared to that of the host T. kodakarensis strain. Increasing the dilution rate to 0.83 h−1 or 1.07 h−1 resulted in a SHPR of 120 mmol H2 g-dcw−1 h−1, which is one of the highest production rates observed in microbial fermentation. PMID:26379632

  7. Krypton Derivatization of an O2 -Tolerant Membrane-Bound [NiFe] Hydrogenase Reveals a Hydrophobic Tunnel Network for Gas Transport.

    PubMed

    Kalms, Jacqueline; Schmidt, Andrea; Frielingsdorf, Stefan; van der Linden, Peter; von Stetten, David; Lenz, Oliver; Carpentier, Philippe; Scheerer, Patrick

    2016-04-25

    [NiFe] hydrogenases are metalloenzymes catalyzing the reversible heterolytic cleavage of hydrogen into protons and electrons. Gas tunnels make the deeply buried active site accessible to substrates and inhibitors. Understanding the architecture and function of the tunnels is pivotal to modulating the feature of O2 tolerance in a subgroup of these [NiFe] hydrogenases, as they are interesting for developments in renewable energy technologies. Here we describe the crystal structure of the O2 -tolerant membrane-bound [NiFe] hydrogenase of Ralstonia eutropha (ReMBH), using krypton-pressurized crystals. The positions of the krypton atoms allow a comprehensive description of the tunnel network within the enzyme. A detailed overview of tunnel sizes, lengths, and routes is presented from tunnel calculations. A comparison of the ReMBH tunnel characteristics with crystal structures of other O2 -tolerant and O2 -sensitive [NiFe] hydrogenases revealed considerable differences in tunnel size and quantity between the two groups, which might be related to the striking feature of O2 tolerance.

  8. Krypton Derivatization of an O2 -Tolerant Membrane-Bound [NiFe] Hydrogenase Reveals a Hydrophobic Tunnel Network for Gas Transport.

    PubMed

    Kalms, Jacqueline; Schmidt, Andrea; Frielingsdorf, Stefan; van der Linden, Peter; von Stetten, David; Lenz, Oliver; Carpentier, Philippe; Scheerer, Patrick

    2016-04-25

    [NiFe] hydrogenases are metalloenzymes catalyzing the reversible heterolytic cleavage of hydrogen into protons and electrons. Gas tunnels make the deeply buried active site accessible to substrates and inhibitors. Understanding the architecture and function of the tunnels is pivotal to modulating the feature of O2 tolerance in a subgroup of these [NiFe] hydrogenases, as they are interesting for developments in renewable energy technologies. Here we describe the crystal structure of the O2 -tolerant membrane-bound [NiFe] hydrogenase of Ralstonia eutropha (ReMBH), using krypton-pressurized crystals. The positions of the krypton atoms allow a comprehensive description of the tunnel network within the enzyme. A detailed overview of tunnel sizes, lengths, and routes is presented from tunnel calculations. A comparison of the ReMBH tunnel characteristics with crystal structures of other O2 -tolerant and O2 -sensitive [NiFe] hydrogenases revealed considerable differences in tunnel size and quantity between the two groups, which might be related to the striking feature of O2 tolerance. PMID:26913499

  9. Production and Application of a Soluble Hydrogenase from Pyrococcus furiosus

    PubMed Central

    Wu, Chang-Hao; McTernan, Patrick M.; Walter, Mary E.; Adams, Michael W. W.

    2015-01-01

    Hydrogen gas is a potential renewable alternative energy carrier that could be used in the future to help supplement humanity's growing energy needs. Unfortunately, current industrial methods for hydrogen production are expensive or environmentally unfriendly. In recent years research has focused on biological mechanisms for hydrogen production and specifically on hydrogenases, the enzyme responsible for catalyzing the reduction of protons to generate hydrogen. In particular, a better understanding of this enzyme might allow us to generate hydrogen that does not use expensive metals, such as platinum, as catalysts. The soluble hydrogenase I (SHI) from the hyperthermophile Pyrococcus furiosus, a member of the euryarchaeota, has been studied extensively and used in various biotechnological applications. This review summarizes the strategies used in engineering and characterizing three different forms of SHI and the properties of the recombinant enzymes. SHI has also been used in in vitro systems for hydrogen production and NADPH generation and these systems are also discussed. PMID:26543406

  10. Production and Application of a Soluble Hydrogenase from Pyrococcus furiosus.

    PubMed

    Wu, Chang-Hao; McTernan, Patrick M; Walter, Mary E; Adams, Michael W W

    2015-01-01

    Hydrogen gas is a potential renewable alternative energy carrier that could be used in the future to help supplement humanity's growing energy needs. Unfortunately, current industrial methods for hydrogen production are expensive or environmentally unfriendly. In recent years research has focused on biological mechanisms for hydrogen production and specifically on hydrogenases, the enzyme responsible for catalyzing the reduction of protons to generate hydrogen. In particular, a better understanding of this enzyme might allow us to generate hydrogen that does not use expensive metals, such as platinum, as catalysts. The soluble hydrogenase I (SHI) from the hyperthermophile Pyrococcus furiosus, a member of the euryarchaeota, has been studied extensively and used in various biotechnological applications. This review summarizes the strategies used in engineering and characterizing three different forms of SHI and the properties of the recombinant enzymes. SHI has also been used in in vitro systems for hydrogen production and NADPH generation and these systems are also discussed. PMID:26543406

  11. Molecular evolution of gas cavity in [NiFeSe] hydrogenases resurrected in silico.

    PubMed

    Tamura, Takashi; Tsunekawa, Naoki; Nemoto, Michiko; Inagaki, Kenji; Hirano, Toshiyuki; Sato, Fumitoshi

    2016-01-01

    Oxygen tolerance of selenium-containing [NiFeSe] hydrogenases (Hases) is attributable to the high reducing power of the selenocysteine residue, which sustains the bimetallic Ni-Fe catalytic center in the large subunit. Genes encoding [NiFeSe] Hases are inherited by few sulphate-reducing δ-proteobacteria globally distributed under various anoxic conditions. Ancestral sequences of [NiFeSe] Hases were elucidated and their three-dimensional structures were recreated in silico using homology modelling and molecular dynamic simulation, which suggested that deep gas channels gradually developed in [NiFeSe] Hases under absolute anaerobic conditions, whereas the enzyme remained as a sealed edifice under environmental conditions of a higher oxygen exposure risk. The development of a gas cavity appears to be driven by non-synonymous mutations, which cause subtle conformational changes locally and distantly, even including highly conserved sequence regions. PMID:26818780

  12. Molecular evolution of gas cavity in [NiFeSe] hydrogenases resurrected in silico

    NASA Astrophysics Data System (ADS)

    Tamura, Takashi; Tsunekawa, Naoki; Nemoto, Michiko; Inagaki, Kenji; Hirano, Toshiyuki; Sato, Fumitoshi

    2016-01-01

    Oxygen tolerance of selenium-containing [NiFeSe] hydrogenases (Hases) is attributable to the high reducing power of the selenocysteine residue, which sustains the bimetallic Ni-Fe catalytic center in the large subunit. Genes encoding [NiFeSe] Hases are inherited by few sulphate-reducing δ-proteobacteria globally distributed under various anoxic conditions. Ancestral sequences of [NiFeSe] Hases were elucidated and their three-dimensional structures were recreated in silico using homology modelling and molecular dynamic simulation, which suggested that deep gas channels gradually developed in [NiFeSe] Hases under absolute anaerobic conditions, whereas the enzyme remained as a sealed edifice under environmental conditions of a higher oxygen exposure risk. The development of a gas cavity appears to be driven by non-synonymous mutations, which cause subtle conformational changes locally and distantly, even including highly conserved sequence regions.

  13. Molecular evolution of gas cavity in [NiFeSe] hydrogenases resurrected in silico

    PubMed Central

    Tamura, Takashi; Tsunekawa, Naoki; Nemoto, Michiko; Inagaki, Kenji; Hirano, Toshiyuki; Sato, Fumitoshi

    2016-01-01

    Oxygen tolerance of selenium-containing [NiFeSe] hydrogenases (Hases) is attributable to the high reducing power of the selenocysteine residue, which sustains the bimetallic Ni–Fe catalytic center in the large subunit. Genes encoding [NiFeSe] Hases are inherited by few sulphate-reducing δ-proteobacteria globally distributed under various anoxic conditions. Ancestral sequences of [NiFeSe] Hases were elucidated and their three-dimensional structures were recreated in silico using homology modelling and molecular dynamic simulation, which suggested that deep gas channels gradually developed in [NiFeSe] Hases under absolute anaerobic conditions, whereas the enzyme remained as a sealed edifice under environmental conditions of a higher oxygen exposure risk. The development of a gas cavity appears to be driven by non-synonymous mutations, which cause subtle conformational changes locally and distantly, even including highly conserved sequence regions. PMID:26818780

  14. Combining Hierarchical and Associative Gene Ontology Relations with Textual Evidence in Estimating Gene and Gene Product Similarity

    SciTech Connect

    Sanfilippo, Antonio P.; Posse, Christian; Gopalan, Banu; Riensche, Roderick M.; Beagley, Nathaniel; Baddeley, Bob L.; Tratz, Stephen C.; Gregory, Michelle L.

    2007-03-01

    Gene and gene product similarity is a fundamental diagnostic measure in analyzing biological data and constructing predictive models for functional genomics. With the rising influence of the Gene Ontology, two complementary approaches have emerged where the similarity between two genes or gene products is obtained by comparing Gene Ontology (GO) annotations associated with the genes or gene products. One approach captures GO-based similarity in terms of hierarchical relations within each gene subontology. The other approach identifies GO-based similarity in terms of associative relations across the three gene subontologies. We propose a novel methodology where the two approaches can be merged with ensuing benefits in coverage and accuracy, and demonstrate that further improvements can be obtained by integrating textual evidence extracted from relevant biomedical literature.

  15. Reconstitution of [Fe]-hydrogenase using model complexes

    NASA Astrophysics Data System (ADS)

    Shima, Seigo; Chen, Dafa; Xu, Tao; Wodrich, Matthew D.; Fujishiro, Takashi; Schultz, Katherine M.; Kahnt, Jörg; Ataka, Kenichi; Hu, Xile

    2015-12-01

    [Fe]-Hydrogenase catalyses the reversible hydrogenation of a methenyltetrahydromethanopterin substrate, which is an intermediate step during the methanogenesis from CO2 and H2. The active site contains an iron-guanylylpyridinol cofactor, in which Fe2+ is coordinated by two CO ligands, as well as an acyl carbon atom and a pyridinyl nitrogen atom from a 3,4,5,6-substituted 2-pyridinol ligand. However, the mechanism of H2 activation by [Fe]-hydrogenase is unclear. Here we report the reconstitution of [Fe]-hydrogenase from an apoenzyme using two FeGP cofactor mimics to create semisynthetic enzymes. The small-molecule mimics reproduce the ligand environment of the active site, but are inactive towards H2 binding and activation on their own. We show that reconstituting the enzyme using a mimic that contains a 2-hydroxypyridine group restores activity, whereas an analogous enzyme with a 2-methoxypyridine complex was essentially inactive. These findings, together with density functional theory computations, support a mechanism in which the 2-hydroxy group is deprotonated before it serves as an internal base for heterolytic H2 cleavage.

  16. [FeFe]-hydrogenase models assembled into vesicular structures.

    PubMed

    Menzel, Kristin; Apfel, Ulf-Peter; Wolter, Nonio; Rüger, Ronny; Alpermann, Theodor; Steiniger, Frank; Gabel, Detlef; Förster, Stephan; Weigand, Wolfgang; Fahr, Alfred

    2014-03-01

    Compartmentalization is a major prerequisite for the origin of life on earth according to Wächtershäuser "Iron-Sulfur-World". The hypothesis is mainly based on an autocatalytic inorganic energy reproducing redox system consisting of iron and sulfur as requirement for the subsequent synthesis of complex organic structures. Here, we modified [FeFe]-hydrogenase models by means of covalent coupling to either oleic acid or the amphiphilic block copolymer polybutadiene-polyethyleneoxide (PB-PEO) and incorporated those into the membranes of vesicles composed of phospholipids (liposomes) or the unmodified amphiphilic polymer (polymersomes). We employed a [2Fe-2S] cluster as a hydrogenase model, since these structures are known to be suitable catalysts for the generation of H2 in the presence of weak acids. Successful incorporation was confirmed by spectrophotometric iron quantification and the vesicles formed were characterized by size determination (photon correlation spectroscopy (PCS)), and zeta potential as well as by cryo-transmission electron microscopy (Cryo-TEM). The modified models could be incorporated into liposomes or polymersomes up to molar proportions of 3.15% and 28%, respectively. Due to the immobilization in vesicular bilayers the [FeFe]-hydrogenase models can even exhibit catalytic action under the particular conditions of the intravesicular microenvironment. Our results suggest that the vesicular systems described may be applied as a nanoreactor for the reduction of encapsulated substances by generating hydrogen and thus as a minimal cell model. PMID:24006843

  17. EPR Spectroscopic Studies of [FeFe]-Hydrogenase Maturation

    PubMed Central

    Suess, Daniel L. M.

    2015-01-01

    Proton reduction and H2 oxidation are key elementary reactions for solar fuel production. Hydrogenases interconvert H+ and H2 with remarkable efficiency and have therefore received much attention in this context. For [FeFe]-hydrogenases, catalysis occurs at a unique cofactor called the H-cluster. In this article, we discuss ways in which EPR spectroscopy has elucidated aspects of the bioassembly of the H-cluster, with a focus on four case studies: EPR spectroscopic identification of a radical en route to the CO and CN− ligands of the H-cluster, tracing 57Fe from the maturase HydG into the H-cluster, characterization of the auxiliary Fe–S cluster in HydG, and isotopic labeling of the CN− ligands of HydA for electronic structure studies of its Hox state. Advances in cell-free maturation protocols have enabled several of these mechanistic studies, and understanding H-cluster maturation may in turn provide insights leading to improvements in hydrogenase production for biotechnological applications. PMID:26508821

  18. Wiring of Photosystem II to Hydrogenase for Photoelectrochemical Water Splitting.

    PubMed

    Mersch, Dirk; Lee, Chong-Yong; Zhang, Jenny Zhenqi; Brinkert, Katharina; Fontecilla-Camps, Juan C; Rutherford, A William; Reisner, Erwin

    2015-07-01

    In natural photosynthesis, light is used for the production of chemical energy carriers to fuel biological activity. The re-engineering of natural photosynthetic pathways can provide inspiration for sustainable fuel production and insights for understanding the process itself. Here, we employ a semiartificial approach to study photobiological water splitting via a pathway unavailable to nature: the direct coupling of the water oxidation enzyme, photosystem II, to the H2 evolving enzyme, hydrogenase. Essential to this approach is the integration of the isolated enzymes into the artificial circuit of a photoelectrochemical cell. We therefore developed a tailor-made hierarchically structured indium-tin oxide electrode that gives rise to the excellent integration of both photosystem II and hydrogenase for performing the anodic and cathodic half-reactions, respectively. When connected together with the aid of an applied bias, the semiartificial cell demonstrated quantitative electron flow from photosystem II to the hydrogenase with the production of H2 and O2 being in the expected two-to-one ratio and a light-to-hydrogen conversion efficiency of 5.4% under low-intensity red-light irradiation. We thereby demonstrate efficient light-driven water splitting using a pathway inaccessible to biology and report on a widely applicable in vitro platform for the controlled coupling of enzymatic redox processes to meaningfully study photocatalytic reactions.

  19. Unusual reaction of [NiFe]-hydrogenases with cyanide.

    PubMed

    Hexter, Suzannah V; Chung, Min-Wen; Vincent, Kylie A; Armstrong, Fraser A

    2014-07-23

    Cyanide reacts rapidly with [NiFe]-hydrogenases (hydrogenase-1 and hydrogenase-2 from Escherichia coli) under mild oxidizing conditions, inhibiting the electrocatalytic oxidation of hydrogen as recorded by protein film electrochemistry. Electrochemical, EPR, and FTIR measurements show that the final enzyme product, formed within a second (even under 100% H2), is the resting state known as Ni-B, which contains a hydroxido-bridged species, Ni(III)-μ(OH)-Fe(II), at the active site. "Cyanide inhibition" is easily reversed because it is simply the reductive activation of Ni-B. This paper brings back into focus an observation originally made in the 1940s that cyanide inhibits microbial H2 oxidation and addresses the interesting mechanism by which cyanide promotes the formation of Ni-B. As a much stronger nucleophile than hydroxide, cyanide binds more rapidly and promotes oxidation of Ni(II) to Ni(III); however, it is quickly replaced by hydroxide which is a far superior bridging ligand.

  20. [FeFe]-hydrogenase models assembled into vesicular structures.

    PubMed

    Menzel, Kristin; Apfel, Ulf-Peter; Wolter, Nonio; Rüger, Ronny; Alpermann, Theodor; Steiniger, Frank; Gabel, Detlef; Förster, Stephan; Weigand, Wolfgang; Fahr, Alfred

    2014-03-01

    Compartmentalization is a major prerequisite for the origin of life on earth according to Wächtershäuser "Iron-Sulfur-World". The hypothesis is mainly based on an autocatalytic inorganic energy reproducing redox system consisting of iron and sulfur as requirement for the subsequent synthesis of complex organic structures. Here, we modified [FeFe]-hydrogenase models by means of covalent coupling to either oleic acid or the amphiphilic block copolymer polybutadiene-polyethyleneoxide (PB-PEO) and incorporated those into the membranes of vesicles composed of phospholipids (liposomes) or the unmodified amphiphilic polymer (polymersomes). We employed a [2Fe-2S] cluster as a hydrogenase model, since these structures are known to be suitable catalysts for the generation of H2 in the presence of weak acids. Successful incorporation was confirmed by spectrophotometric iron quantification and the vesicles formed were characterized by size determination (photon correlation spectroscopy (PCS)), and zeta potential as well as by cryo-transmission electron microscopy (Cryo-TEM). The modified models could be incorporated into liposomes or polymersomes up to molar proportions of 3.15% and 28%, respectively. Due to the immobilization in vesicular bilayers the [FeFe]-hydrogenase models can even exhibit catalytic action under the particular conditions of the intravesicular microenvironment. Our results suggest that the vesicular systems described may be applied as a nanoreactor for the reduction of encapsulated substances by generating hydrogen and thus as a minimal cell model.

  1. Reproduction-related genes in the pearl oyster genome.

    PubMed

    Matsumoto, Toshie; Masaoka, Tetsuji; Fujiwara, Atsushi; Nakamura, Yoji; Satoh, Nori; Awaji, Masahiko

    2013-10-01

    Molluscan reproduction has been a target of biological research because of the various reproductive strategies that have evolved in this phylum. It has also been studied for the development of fisheries technologies, particularly aquaculture. Although fundamental processes of reproduction in other phyla, such as vertebrates and arthropods, have been well studied, information on the molecular mechanisms of molluscan reproduction remains limited. The recently released draft genome of the pearl oyster Pinctada fucata provides a novel and powerful platform for obtaining structural information on the genes and proteins involved in bivalve reproduction. In the present study, we analyzed the pearl oyster draft genome to screen reproduction-related genes. Analysis was mainly conducted for genes reported from other molluscs for encoding orthologs of reproduction-related proteins in other phyla. The gene search in the P. fucata gene models (version 1.1) and genome assembly (version 1.0) were performed using Genome Browser and BLAST software. The obtained gene models were then BLASTP searched against a public database to confirm the best-hit sequences. As a result, more than 40 gene models were identified with high accuracy to encode reproduction-related genes reported for P. fucata and other molluscs. These include vasa, nanos, doublesex- and mab-3-related transcription factor, 5-hydroxytryptamine (5-HT) receptors, vitellogenin, estrogen receptor, and others. The set of reproduction-related genes of P. fucata identified in the present study constitute a new tool for research on bivalve reproduction at the molecular level.

  2. Fruit growth-related genes in tomato.

    PubMed

    Azzi, Lamia; Deluche, Cynthia; Gévaudant, Frédéric; Frangne, Nathalie; Delmas, Frédéric; Hernould, Michel; Chevalier, Christian

    2015-02-01

    Tomato (Solanum lycopersicum Mill.) represents a model species for all fleshy fruits due to its biological cycle and the availability of numerous genetic and molecular resources. Its importance in human nutrition has made it one of the most valuable worldwide commodities. Tomato fruit size results from the combination of cell number and cell size, which are determined by both cell division and expansion. As fruit growth is mainly driven by cell expansion, cells from the (fleshy) pericarp tissue become highly polyploid according to the endoreduplication process, reaching a DNA content rarely encountered in other plant species (between 2C and 512C). Both cell division and cell expansion are under the control of complex interactions between hormone signalling and carbon partitioning, which establish crucial determinants of the quality of ripe fruit, such as the final size, weight, and shape, and organoleptic and nutritional traits. This review describes the genes known to contribute to fruit growth in tomato.

  3. Amplification of a Gene Related to Mammalian mdr Genes in Drug-Resistant Plasmodium falciparum

    NASA Astrophysics Data System (ADS)

    Wilson, Craig M.; Serrano, Adelfa E.; Wasley, Annemarie; Bogenschutz, Michael P.; Shankar, Anuraj H.; Wirth, Dyann F.

    1989-06-01

    The malaria parasite Plasmodium falciparum contains at least two genes related to the mammalian multiple drug resistance genes, and at least one of the P. falciparum genes is expressed at a higher level and is present in higher copy number in a strain that is resistant to multiple drugs than in a strain that is sensitive to the drugs.

  4. Enhanced Hydrogen Production by Co-cultures of Hydrogenase and Nitrogenase in Escherichia coli.

    PubMed

    Lee, Hyun Jeong; Sekhon, Simranjeet Singh; Kim, Young Su; Park, Ju-Yong; Kim, Yang-Hoon; Min, Jiho

    2016-03-01

    Rhodobacter sphaeroides is a bacterium that can produce hydrogen by interaction with hydrogenase and nitrogenase. We report a hydrogen production system using co-cultivation of hydrogenase in liquid medium and immobilized nitrogenase in Escherichia coli. The recombinant plasmid has been constructed to analyze the effect of hydrogen production on the expression of hupSL hydrogenase and nifHDK nitrogenase isolated from R. sphaeroides. All recombinant E. coli strains were cultured anaerobically, and cells for nitrogenase were immobilized in agar gel, whereas cells for hydrogenase were supplemented on the nitrogenase agar gel. The hupSL hydrogenase has been observed to enhance hydrogen production and hydrogenase activity under co-culture with nifHDK nitrogenase. The maximum hydrogen production has been obtained at an agar gel concentration and a cell concentration for co-culture of 2 % and 6.4 × 10(8) CFU. Thus, co-culture of hupSL hydrogenase and nifHDK nitrogenase provides a promising route for enhancing the hydrogen production and hydrogenase activity.

  5. Biomimetic assembly of the [FeFe] hydrogenase: synthetic mimics in a biological shell.

    PubMed

    Apfel, Ulf-Peter; Weigand, Wolfgang

    2013-11-25

    Combining synthetic chemistry and biology: A new method that allows the incorporation of synthetic [FeFe] hydrogenase mimics into the apo-hydrogenase is highlighted. Azadithiolato-functionalized model complexes showed similar activity to wild-type enzymes when implemented into the protein.

  6. [Research progress in relative crystallin genes of congenital cataract].

    PubMed

    Wang, D D; Yang, H J; Yi, J L

    2016-02-01

    Congenital cataract is the common cause of visual disability in children. Nearly one third of congenital cataract cases may have a related genetic mutation. With the development of molecular genetics, especially gentechnik, more and more genes, such as crystallin genes, membrane protein genes, eytoskeletal protein genes and regulatory protein genes have been confirmed to participate in the process of congenital cataract. Furthermore, crystallin genes account for most of these genes and the crystallin has the highest amount of the whole protein in lens.It has been found that nearly one hundred mutations in crystallin genes are associated with the onset of congenital cataract. Researchers are exploring how these mutations further affect the function of cellular biology and eventually lead to cataract. Although more and more research results gradually reveal the pathogenesis of congenital cataract from the level of gene and protein, the specific pathogenesis is still unclear. The recent progression about inherited congenital cataract related with crysallin genes is summarized in this review.

  7. Hydrogenase-based nanomaterials as anode electrode catalyst in polymer electrolyte fuel cells

    NASA Astrophysics Data System (ADS)

    Tsuda, Muneyuki; Diño, Wilson Agerico; Kasai, Hideaki

    2005-03-01

    We consider hydrogenase-based nanomaterials for possible use as anode electrode catalysts in polymer electrolyte fuel cells (PEFCs). We choose Fe-only hydrogenase component of Desulfovibrio desulfuricans (DdHase) as a hydrogenase complex, and investigate its catalytic activity for H 2 dissociation using ab initio calculations based on density functional theory (DFT). We found two possible H-H bond cleavage pathways, which are heterolytic and possess low activation barriers. Moreover, the H 2 dissociation can be promoted by inducing spin polarization of the H 2 adduct. We report that hydrogenase or hydrogenase-based nanomaterials can manipulate to exhibit the catalytic activity equivalent to the well-known platinum catalyst.

  8. Brownian dynamics and molecular dynamics study of the association between hydrogenase and ferredoxin from Chlamydomonas reinhardtii.

    PubMed

    Long, Hai; Chang, Christopher H; King, Paul W; Ghirardi, Maria L; Kim, Kwiseon

    2008-10-01

    The [FeFe] hydrogenase from the green alga Chlamydomonas reinhardtii can catalyze the reduction of protons to hydrogen gas using electrons supplied from photosystem I and transferred via ferredoxin. To better understand the association of the hydrogenase and the ferredoxin, we have simulated the process over multiple timescales. A Brownian dynamics simulation method gave an initial thorough sampling of the rigid-body translational and rotational phase spaces, and the resulting trajectories were used to compute the occupancy and free-energy landscapes. Several important hydrogenase-ferredoxin encounter complexes were identified from this analysis, which were then individually simulated using atomistic molecular dynamics to provide more details of the hydrogenase and ferredoxin interaction. The ferredoxin appeared to form reasonable complexes with the hydrogenase in multiple orientations, some of which were good candidates for inclusion in a transition state ensemble of configurations for electron transfer. PMID:18621810

  9. Detection and localization of two hydrogenases in Methylococcus capsulatus (Bath) and their potential role in methane metabolism.

    PubMed

    Hanczár, Tímea; Csáki, Robert; Bodrossy, Levente; Murrell, J Colin; Kovács, Kornél L

    2002-02-01

    Methylococcus capsulatus (Bath) was shown to contain two distinct hydrogenases, a soluble hydrogenase and a membrane-bound hydrogenase. This is the first report of a membrane-bound hydrogenase in methanotrophs. Both enzymes were expressed apparently constitutively under normal growth conditions. The soluble hydrogenase was capable of reducing NAD(+) with molecular hydrogen. The activities of both soluble and particulate methane monooxygenases could be driven by molecular hydrogen. This confirmed that molecular hydrogen could be used as a source of reducing power for methane oxidation. Hydrogen-driven methane monooxygenase activities tolerated elevated temperatures and moderate oxygen concentrations. The significance of these findings for biotechnological applications of methanotrophs is discussed. PMID:11807566

  10. Relating significance and relations of differentially expressed genes in response to Aspergillus flavus infection in maize.

    PubMed

    Asters, Matthew C; Williams, W Paul; Perkins, Andy D; Mylroie, J Erik; Windham, Gary L; Shan, Xueyan

    2014-01-01

    Aspergillus flavus is a pathogenic fungus infecting maize and producing aflatoxins that are health hazards to humans and animals. Characterizing host defense mechanism and prioritizing candidate resistance genes are important to the development of resistant maize germplasm. We investigated methods amenable for the analysis of the significance and relations among maize candidate genes based on the empirical gene expression data obtained by RT-qPCR technique from maize inbred lines. We optimized a pipeline of analysis tools chosen from various programs to provide rigorous statistical analysis and state of the art data visualization. A network-based method was also explored to construct the empirical gene expression relational structures. Maize genes at the centers in the network were considered as important candidate genes for maize DNA marker studies. The methods in this research can be used to analyze large RT-qPCR datasets and establish complex empirical gene relational structures across multiple experimental conditions. PMID:24770700

  11. Relating significance and relations of differentially expressed genes in response to Aspergillus flavus infection in maize

    PubMed Central

    Asters, Matthew C.; Williams, W. Paul; Perkins, Andy D.; Mylroie, J. Erik; Windham, Gary L.; Shan, Xueyan

    2014-01-01

    Aspergillus flavus is a pathogenic fungus infecting maize and producing aflatoxins that are health hazards to humans and animals. Characterizing host defense mechanism and prioritizing candidate resistance genes are important to the development of resistant maize germplasm. We investigated methods amenable for the analysis of the significance and relations among maize candidate genes based on the empirical gene expression data obtained by RT-qPCR technique from maize inbred lines. We optimized a pipeline of analysis tools chosen from various programs to provide rigorous statistical analysis and state of the art data visualization. A network-based method was also explored to construct the empirical gene expression relational structures. Maize genes at the centers in the network were considered as important candidate genes for maize DNA marker studies. The methods in this research can be used to analyze large RT-qPCR datasets and establish complex empirical gene relational structures across multiple experimental conditions. PMID:24770700

  12. Rare disease relations through common genes and protein interactions.

    PubMed

    Fernandez-Novo, Sara; Pazos, Florencio; Chagoyen, Monica

    2016-06-01

    ODCs (Orphan Disease Connections), available at http://csbg.cnb.csic.es/odcs, is a novel resource to explore potential molecular relations between rare diseases. These molecular relations have been established through the integration of disease susceptibility genes and human protein-protein interactions. The database currently contains 54,941 relations between 3032 diseases.

  13. DRUMS: a human disease related unique gene mutation search engine.

    PubMed

    Li, Zuofeng; Liu, Xingnan; Wen, Jingran; Xu, Ye; Zhao, Xin; Li, Xuan; Liu, Lei; Zhang, Xiaoyan

    2011-10-01

    With the completion of the human genome project and the development of new methods for gene variant detection, the integration of mutation data and its phenotypic consequences has become more important than ever. Among all available resources, locus-specific databases (LSDBs) curate one or more specific genes' mutation data along with high-quality phenotypes. Although some genotype-phenotype data from LSDB have been integrated into central databases little effort has been made to integrate all these data by a search engine approach. In this work, we have developed disease related unique gene mutation search engine (DRUMS), a search engine for human disease related unique gene mutation as a convenient tool for biologists or physicians to retrieve gene variant and related phenotype information. Gene variant and phenotype information were stored in a gene-centred relational database. Moreover, the relationships between mutations and diseases were indexed by the uniform resource identifier from LSDB, or another central database. By querying DRUMS, users can access the most popular mutation databases under one interface. DRUMS could be treated as a domain specific search engine. By using web crawling, indexing, and searching technologies, it provides a competitively efficient interface for searching and retrieving mutation data and their relationships to diseases. The present system is freely accessible at http://www.scbit.org/glif/new/drums/index.html.

  14. The Model [NiFe]-Hydrogenases of Escherichia coli.

    PubMed

    Sargent, F

    2016-01-01

    In Escherichia coli, hydrogen metabolism plays a prominent role in anaerobic physiology. The genome contains the capability to produce and assemble up to four [NiFe]-hydrogenases, each of which are known, or predicted, to contribute to different aspects of cellular metabolism. In recent years, there have been major advances in the understanding of the structure, function, and roles of the E. coli [NiFe]-hydrogenases. The membrane-bound, periplasmically oriented, respiratory Hyd-1 isoenzyme has become one of the most important paradigm systems for understanding an important class of oxygen-tolerant enzymes, as well as providing key information on the mechanism of hydrogen activation per se. The membrane-bound, periplasmically oriented, Hyd-2 isoenzyme has emerged as an unusual, bidirectional redox valve able to link hydrogen oxidation to quinone reduction during anaerobic respiration, or to allow disposal of excess reducing equivalents as hydrogen gas. The membrane-bound, cytoplasmically oriented, Hyd-3 isoenzyme is part of the formate hydrogenlyase complex, which acts to detoxify excess formic acid under anaerobic fermentative conditions and is geared towards hydrogen production under those conditions. Sequence identity between some Hyd-3 subunits and those of the respiratory NADH dehydrogenases has led to hypotheses that the activity of this isoenzyme may be tightly coupled to the formation of transmembrane ion gradients. Finally, the E. coli genome encodes a homologue of Hyd-3, termed Hyd-4, however strong evidence for a physiological role for E. coli Hyd-4 remains elusive. In this review, the versatile hydrogen metabolism of E. coli will be discussed and the roles and potential applications of the spectrum of different types of [NiFe]-hydrogenases available will be explored. PMID:27134027

  15. In vitro hydrogen production by glucose dehydrogenase and hydrogenase

    SciTech Connect

    Woodward, J.; Mattingly, S.M.; Danson, M.

    1996-07-01

    A new in vitro enzymatic pathway for the generation of molecular hydrogen from glucose has been demonstrated. The reaction is based on the oxidation of glucose by Thermoplasma acidophilum glucose dehydrogenase with the concomitant oxidation of NADPH by Pyrococcus furiosus hydrogenase. Stoichiometric yields of hydrogen were produced from glucose with the continuous recycling of cofactor. This simple system may provide a method for the biological production of hydrogen from renewable sources. In addition, the other product of this reaction, gluconic acid, is a high-value chemical commodity. 23 refs., 5 figs.

  16. In vitro hydrogen production by glucose dehydrogenase and hydrogenase

    SciTech Connect

    Woodward, J.

    1996-10-01

    A new in vitro enzymatic pathway for the generation of molecular hydrogen from glucose has been demonstrated. The reaction is based upon the oxidation of glucose by Thermoplasma acidophilum glucose dehydrogenase with the concomitant oxidation of NADPH by Pyrococcus furiosus hydrogenase. Stoichiometric yields of hydrogen were produced from glucose with continuous cofactor recycle. This simple system may provide a method for the biological production of hydrogen from renewable sources. In addition, the other product of this reaction, gluconic acid, is a high-value commodity chemical.

  17. Relating Perturbation Magnitude to Temporal Gene Expression in Biological Systems

    SciTech Connect

    Callister, Stephen J.; Parnell, John J.; Pfrender, Michael E.; Hashsham, Syed

    2009-03-19

    A method to quantitatively relate stress to response at the level of gene expression is described using Saccharomyces cerevisiae as a model organism. Stress was defined as the magnitude of perturbation and strain was defined as the magnitude of cumulative response in terms of gene expression. Expression patterns of sixty genes previously reported to be significantly impacted by osmotic shock or belonging to the high-osmotic glycerol, glycerolipid metabolism, and glycolysis pathways were determined following perturbations of increasing sodium chloride concentrations (0, 0.5, 0.7, 1.0, 1.5, and 1.4 M). Expression of these genes was quantified temporally using reverse transcriptase real time polymerase chain reaction. The magnitude of cumulative response was obtained by calculating the total moment of area of the temporal response envelope for all the 60 genes, either together or for the set of genes related to each pathway. A non-linear relationship between stress and response was observed for the range of stress studied. This study examines a quantitative approach to quantify the strain at the level of gene expression to relate stress to strain in biological systems. The approach should be generally applicable to quantitatively evaluate the response of organisms to environmental change.

  18. Review of Literature: Genes Related to Postaxial Polydactyly

    PubMed Central

    Verma, Prashant Kumar; El-Harouni, Ashraf A.

    2015-01-01

    Background: Postaxial polydactyly (PAP) is one of the commonest congenital malformations and usually is associated to several syndromes. There is no primary investigational strategy for PAP cases with single gene disorder in literature. PAP cases with single gene disorder can be classified according to common pathways and molecular basis. Molecular classification may help in diagnostic approach. Materials and Methods: All single gene disorders associated with PAP reported on PubMed and OMIM are analyzed and classified according to molecular basis. Results: Majority of genes related to cilia structure and functions are associated with PAP, so we classified them as ciliopathies and non-ciliopathies groups. Genes related to Shh–Gli3 pathway was the commonest group in non-ciliopathies. Conclusion: Genes related to cilia are most commonly related to PAP due to their indirect relationship to Shh–Gli3 signaling pathway. Initially, PAP may be the only clinical finding with ciliopathies so those cases need follow up. Proper diagnosis is helpful for management and genetic counseling. Molecular approach may help to define pleiotropy. PMID:25717468

  19. HydDB: A web tool for hydrogenase classification and analysis

    PubMed Central

    Søndergaard, Dan; Pedersen, Christian N. S.; Greening, Chris

    2016-01-01

    H2 metabolism is proposed to be the most ancient and diverse mechanism of energy-conservation. The metalloenzymes mediating this metabolism, hydrogenases, are encoded by over 60 microbial phyla and are present in all major ecosystems. We developed a classification system and web tool, HydDB, for the structural and functional analysis of these enzymes. We show that hydrogenase function can be predicted by primary sequence alone using an expanded classification scheme (comprising 29 [NiFe], 8 [FeFe], and 1 [Fe] hydrogenase classes) that defines 11 new classes with distinct biological functions. Using this scheme, we built a web tool that rapidly and reliably classifies hydrogenase primary sequences using a combination of k-nearest neighbors’ algorithms and CDD referencing. Demonstrating its capacity, the tool reliably predicted hydrogenase content and function in 12 newly-sequenced bacteria, archaea, and eukaryotes. HydDB provides the capacity to browse the amino acid sequences of 3248 annotated hydrogenase catalytic subunits and also contains a detailed repository of physiological, biochemical, and structural information about the 38 hydrogenase classes defined here. The database and classifier are freely and publicly available at http://services.birc.au.dk/hyddb/ PMID:27670643

  20. Hydrogen Production Catalyzed by Bidirectional, Biomimetic Models of the [FeFe]-Hydrogenase Active Site.

    PubMed

    Lansing, James C; Camara, James M; Gray, Danielle E; Rauchfuss, Thomas B

    2014-10-27

    Active site mimics of [FeFe]-hydrogenase are shown to be bidirectional catalysts, producing H2 upon treatment with protons and reducing equivalents. This reactivity complements the previously reported oxidation of H2 by these same catalysts in the presence of oxidants. The complex Fe2(adt(Bn))(CO)3(dppv)(PFc*(Et2) ) ([1](0); adt(Bn) = (SCH2)2NBn, dppv = cis-1,2-bis(diphenylphosphino)ethylene, PFc*(Et2) = Et2PCH2C5Me4FeCp*) reacts with excess [H(OEt2)2]BAr(F) 4 (BAr(F) 4 (-) = B(C6H3-3,5-(CF3)2)4 (-)) to give ∼0.5 equiv of H2 and [Fe2(adt(Bn)H)(CO)3(dppv)(PFc*(Et2) )](2+) ([1H](2+)). The species [1H](2+) consists of a ferrocenium ligand, an N-protonated amine, and an Fe(I)Fe(I) core. In the presence of additional reducing equivalents in the form of decamethylferrocene (Fc*), hydrogen evolution is catalytic, albeit slow. The related catalyst Fe2(adt(Bn))(CO)3(dppv)(PMe3) (3) behaves similarly in the presence of Fc*, except that in the absence of excess reducing agent it converts to the catalytically inactive μ-hydride derivative [μ-H3](+). Replacement of the adt in [1](0) with propanedithiolate (pdt) results in a catalytically inactive complex. In the course of synthesizing [FeFe]-hydrogenase mimics, new routes to ferrocenylphosphine ligands and nonamethylferrocene were developed. PMID:25364093

  1. Transcriptional wiring of cell wall-related genes in Arabidopsis.

    PubMed

    Mutwil, Marek; Ruprecht, Colin; Giorgi, Federico M; Bringmann, Martin; Usadel, Björn; Persson, Staffan

    2009-09-01

    Transcriptional coordination, or co-expression, of genes may signify functional relatedness of the corresponding proteins. For example, several genes involved in secondary cell wall cellulose biosynthesis are co-expressed with genes engaged in the synthesis of xylan, which is a major component of the secondary cell wall. To extend these types of analyses, we investigated the co-expression relationships of all Carbohydrate-Active enZYmes (CAZy)-related genes for Arabidopsis thaliana. Thus, the intention was to transcriptionally link different cell wall-related processes to each other, and also to other biological functions. To facilitate easy manual inspection, we have displayed these interactions as networks and matrices, and created a web-based interface (http://aranet.mpimp-golm.mpg.de/corecarb) containing downloadable files for all the transcriptional associations.

  2. A complex network analysis of hypertension-related genes

    NASA Astrophysics Data System (ADS)

    Wang, Huan; Xu, Chuan-Yun; Hu, Jing-Bo; Cao, Ke-Fei

    2014-01-01

    In this paper, a network of hypertension-related genes is constructed by analyzing the correlations of gene expression data among the Dahl salt-sensitive rat and two consomic rat strains. The numerical calculations show that this sparse and assortative network has small-world and scale-free properties. Further, 16 key hub genes (Col4a1, Lcn2, Cdk4, etc.) are determined by introducing an integrated centrality and have been confirmed by biological/medical research to play important roles in hypertension.

  3. A graphic method for identification of novel glioma related genes.

    PubMed

    Gao, Yu-Fei; Shu, Yang; Yang, Lei; He, Yi-Chun; Li, Li-Peng; Huang, GuaHua; Li, Hai-Peng; Jiang, Yang

    2014-01-01

    Glioma, as the most common and lethal intracranial tumor, is a serious disease that causes many deaths every year. Good comprehension of the mechanism underlying this disease is very helpful to design effective treatments. However, up to now, the knowledge of this disease is still limited. It is an important step to understand the mechanism underlying this disease by uncovering its related genes. In this study, a graphic method was proposed to identify novel glioma related genes based on known glioma related genes. A weighted graph was constructed according to the protein-protein interaction information retrieved from STRING and the well-known shortest path algorithm was employed to discover novel genes. The following analysis suggests that some of them are related to the biological process of glioma, proving that our method was effective in identifying novel glioma related genes. We hope that the proposed method would be applied to study other diseases and provide useful information to medical workers, thereby designing effective treatments of different diseases.

  4. Consequences of recurrent gene flow from crops to wild relatives.

    PubMed

    Haygood, Ralph; Ives, Anthony R; Andow, David A

    2003-09-22

    Concern about gene flow from crops to wild relatives has become widespread with the increasing cultivation of transgenic crops. Possible consequences of such gene flow include genetic assimilation, wherein crop genes replace wild ones, and demographic swamping, wherein hybrids are less fertile than their wild parents, and wild populations shrink. Using mathematical models of a wild population recurrently receiving pollen from a genetically fixed crop, we find that the conditions for genetic assimilation are not stringent, and progress towards replacement can be fast, even for disfavoured crop genes. Demographic swamping and genetic drift relax the conditions for genetic assimilation and speed progress towards replacement. Genetic assimilation can involve thresholds and hysteresis, such that a small increase in immigration can lead to fixation of a disfavoured crop gene that had been maintained at a moderate frequency, even if the increase in immigration is cancelled before the gene fixes. Demographic swamping can give rise to 'migrational meltdown', such that a small increase in immigration can lead to not only fixation of a disfavoured crop gene but also drastic shrinkage of the wild population. These findings suggest that the spread of crop genes in wild populations should be monitored more closely. PMID:14561300

  5. Consequences of recurrent gene flow from crops to wild relatives.

    PubMed Central

    Haygood, Ralph; Ives, Anthony R; Andow, David A

    2003-01-01

    Concern about gene flow from crops to wild relatives has become widespread with the increasing cultivation of transgenic crops. Possible consequences of such gene flow include genetic assimilation, wherein crop genes replace wild ones, and demographic swamping, wherein hybrids are less fertile than their wild parents, and wild populations shrink. Using mathematical models of a wild population recurrently receiving pollen from a genetically fixed crop, we find that the conditions for genetic assimilation are not stringent, and progress towards replacement can be fast, even for disfavoured crop genes. Demographic swamping and genetic drift relax the conditions for genetic assimilation and speed progress towards replacement. Genetic assimilation can involve thresholds and hysteresis, such that a small increase in immigration can lead to fixation of a disfavoured crop gene that had been maintained at a moderate frequency, even if the increase in immigration is cancelled before the gene fixes. Demographic swamping can give rise to 'migrational meltdown', such that a small increase in immigration can lead to not only fixation of a disfavoured crop gene but also drastic shrinkage of the wild population. These findings suggest that the spread of crop genes in wild populations should be monitored more closely. PMID:14561300

  6. Consequences of recurrent gene flow from crops to wild relatives.

    PubMed

    Haygood, Ralph; Ives, Anthony R; Andow, David A

    2003-09-22

    Concern about gene flow from crops to wild relatives has become widespread with the increasing cultivation of transgenic crops. Possible consequences of such gene flow include genetic assimilation, wherein crop genes replace wild ones, and demographic swamping, wherein hybrids are less fertile than their wild parents, and wild populations shrink. Using mathematical models of a wild population recurrently receiving pollen from a genetically fixed crop, we find that the conditions for genetic assimilation are not stringent, and progress towards replacement can be fast, even for disfavoured crop genes. Demographic swamping and genetic drift relax the conditions for genetic assimilation and speed progress towards replacement. Genetic assimilation can involve thresholds and hysteresis, such that a small increase in immigration can lead to fixation of a disfavoured crop gene that had been maintained at a moderate frequency, even if the increase in immigration is cancelled before the gene fixes. Demographic swamping can give rise to 'migrational meltdown', such that a small increase in immigration can lead to not only fixation of a disfavoured crop gene but also drastic shrinkage of the wild population. These findings suggest that the spread of crop genes in wild populations should be monitored more closely.

  7. Production and Application of a Soluble Hydrogenase from Pyrococcus furiosus

    DOE PAGESBeta

    Wu, Chang-Hao; McTernan, Patrick M.; Walter, Mary E.; Adams, Michael W. W.

    2015-01-01

    Hydrogen gas is a potential renewable alternative energy carrier that could be used in the future to help supplement humanity’s growing energy needs. Unfortunately, current industrial methods for hydrogen production are expensive or environmentally unfriendly. In recent years research has focused on biological mechanisms for hydrogen production and specifically on hydrogenases, the enzyme responsible for catalyzing the reduction of protons to generate hydrogen. In particular, a better understanding of this enzyme might allow us to generate hydrogen that does not use expensive metals, such as platinum, as catalysts. The soluble hydrogenase I (SHI) from the hyperthermophile Pyrococcus furiosus ,more » a member of the euryarchaeota, has been studied extensively and used in various biotechnological applications. This review summarizes the strategies used in engineering and characterizing three different forms of SHI and the properties of the recombinant enzymes. SHI has also been used in in vitro systems for hydrogen production and NADPH generation and these systems are also discussed.« less

  8. Expression of fibrosis-related genes in canine chronic hepatitis.

    PubMed

    Kanemoto, H; Ohno, K; Sakai, M; Nakashima, K; Takahashi, M; Fujino, Y; Tsujimoto, H

    2011-07-01

    Molecular regulation of fibrosis in chronic canine hepatitis is poorly understood. The authors employed quantitative polymerase chain reaction (PCR) to determine the expression levels of genes reported to be related to fibrosis in other species (human, mouse, and rat) and to elucidate the relationship of these genes with the degree of fibrosis and the presence or absence of ascites and/or jaundice in dogs with hepatitis. Nine fibrosis-related genes were assayed: PDGFB, PDGFD, MMP2, TIMP1, THBS1, COL1A1, COL3A1, TGFB1, and TGFB2. Liver samples of 15 dogs with chronic hepatitis and 4 healthy control dogs were obtained via laparoscopic biopsy and subjected to histologic and quantitative PCR analyses. The expression of all 9 genes showed significant positive correlation (P<.01, r>.70) with the degree of fibrosis. Furthermore, the expression levels of all genes except TGFB1 were significantly higher (P<.05) in dogs with hepatic failure-related symptoms (ascites/jaundice). Results suggest that these 9 genes are integral to the development of fibrosis in canine chronic hepatitis.

  9. Construction and use of a Cupriavidus necator H16 soluble hydrogenase promoter (PSH) fusion to gfp (green fluorescent protein).

    PubMed

    Jugder, Bat-Erdene; Welch, Jeffrey; Braidy, Nady; Marquis, Christopher P

    2016-01-01

    Hydrogenases are metalloenzymes that reversibly catalyse the oxidation or production of molecular hydrogen (H2). Amongst a number of promising candidates for application in the oxidation of H2 is a soluble [Ni-Fe] uptake hydrogenase (SH) produced by Cupriavidus necator H16. In the present study, molecular characterisation of the SH operon, responsible for functional SH synthesis, was investigated by developing a green fluorescent protein (GFP) reporter system to characterise PSH promoter activity using several gene cloning approaches. A PSH promoter-gfp fusion was successfully constructed and inducible GFP expression driven by the PSH promoter under de-repressing conditions in heterotrophic growth media was demonstrated in the recombinant C. necator H16 cells. Here we report the first successful fluorescent reporter system to study PSH promoter activity in C. necator H16. The fusion construct allowed for the design of a simple screening assay to evaluate PSH activity. Furthermore, the constructed reporter system can serve as a model to develop a rapid fluorescent based reporter for subsequent small-scale process optimisation experiments for SH expression. PMID:27547572

  10. Disruption of the Operon Encoding Ehb Hydrogenase Limits AnabolicCO2 Assimilation in the Archaeon Methanococcus maripaludis

    SciTech Connect

    Porat, Iris; Kim, Wonduck; Hendrickson, Erik L.; Xia, Qiangwei; Zhang, Yi; Wang, Tiansong; Taub, Fred; Moore, Brian C.; Anderson, IainJ.; Hackett, Murray; Leigh, John A.; Whitman, William B.

    2006-02-01

    Methanococcus maripaludis is a mesophilic archaeon thatreduces CO2 to methane with H2 or formate as an energy source. Itcontains two membrane-bound energy-conserving hydrogenases, Eha and Ehb.To determine therole of Ehb, a deletion in the ehb operon wasconstructed to yield the mutant, strain S40. Growth of S40 was severelyimpaired in minimal medium. Both acetate and yeast extract were necessaryto restore growth to nearly wild-type levels, suggesting that Ehb wasinvolved in multiple steps in carbon assimilation. However, nodifferences in the total hydrogenase specific activities were foundbetween the wild type and mutant in either cell extracts ormembrane-purified fractions. Methanogenesis by resting cells withpyruvate as the electron donor was also reduced by 30 percent in S40,suggesting a defect in pyruvate oxidation. CO dehydrogenase/acetylcoenzyme A (CoA) synthase and pyruvate oxidoreductase had higher specificactivities in the mutant, and genes encoding these enzymes, as well asAMP-forming acetyl-CoA synthetase, were expressed at increased levels.These observations support a role for Ehb in anabolic CO2 assimilation inmethanococci.

  11. Construction and use of a Cupriavidus necator H16 soluble hydrogenase promoter (PSH) fusion to gfp (green fluorescent protein)

    PubMed Central

    Jugder, Bat-Erdene; Welch, Jeffrey; Braidy, Nady

    2016-01-01

    Hydrogenases are metalloenzymes that reversibly catalyse the oxidation or production of molecular hydrogen (H2). Amongst a number of promising candidates for application in the oxidation of H2 is a soluble [Ni–Fe] uptake hydrogenase (SH) produced by Cupriavidus necator H16. In the present study, molecular characterisation of the SH operon, responsible for functional SH synthesis, was investigated by developing a green fluorescent protein (GFP) reporter system to characterise PSH promoter activity using several gene cloning approaches. A PSH promoter-gfp fusion was successfully constructed and inducible GFP expression driven by the PSH promoter under de-repressing conditions in heterotrophic growth media was demonstrated in the recombinant C. necator H16 cells. Here we report the first successful fluorescent reporter system to study PSH promoter activity in C. necator H16. The fusion construct allowed for the design of a simple screening assay to evaluate PSH activity. Furthermore, the constructed reporter system can serve as a model to develop a rapid fluorescent based reporter for subsequent small-scale process optimisation experiments for SH expression. PMID:27547572

  12. Construction and use of a Cupriavidus necator H16 soluble hydrogenase promoter (PSH) fusion to gfp (green fluorescent protein).

    PubMed

    Jugder, Bat-Erdene; Welch, Jeffrey; Braidy, Nady; Marquis, Christopher P

    2016-01-01

    Hydrogenases are metalloenzymes that reversibly catalyse the oxidation or production of molecular hydrogen (H2). Amongst a number of promising candidates for application in the oxidation of H2 is a soluble [Ni-Fe] uptake hydrogenase (SH) produced by Cupriavidus necator H16. In the present study, molecular characterisation of the SH operon, responsible for functional SH synthesis, was investigated by developing a green fluorescent protein (GFP) reporter system to characterise PSH promoter activity using several gene cloning approaches. A PSH promoter-gfp fusion was successfully constructed and inducible GFP expression driven by the PSH promoter under de-repressing conditions in heterotrophic growth media was demonstrated in the recombinant C. necator H16 cells. Here we report the first successful fluorescent reporter system to study PSH promoter activity in C. necator H16. The fusion construct allowed for the design of a simple screening assay to evaluate PSH activity. Furthermore, the constructed reporter system can serve as a model to develop a rapid fluorescent based reporter for subsequent small-scale process optimisation experiments for SH expression.

  13. Fractionation of sulfur isotopes by Desulfovibrio vulgaris mutants lacking hydrogenases or type I tetraheme cytochrome c3

    PubMed Central

    Sim, Min Sub; Wang, David T.; Zane, Grant M.; Wall, Judy D.; Bosak, Tanja; Ono, Shuhei

    2013-01-01

    The sulfur isotope effect produced by sulfate reducing microbes is commonly used to trace biogeochemical cycles of sulfur and carbon in aquatic and sedimentary environments. To test the contribution of intracellular coupling between carbon and sulfur metabolisms to the overall magnitude of the sulfur isotope effect, this study compared sulfur isotope fractionations by mutants of Desulfovibrio vulgaris Hildenborough. We tested mutant strains lacking one or two periplasmic (Hyd, Hyn-1, Hyn-2, and Hys) or cytoplasmic hydrogenases (Ech and CooL), and a mutant lacking type I tetraheme cytochrome (TpI-c3). In batch culture, wild-type D. vulgaris and its hydrogenase mutants had comparable growth kinetics and produced the same sulfur isotope effects. This is consistent with the reported redundancy of hydrogenases in D. vulgaris. However, the TpI-c3 mutant (ΔcycA) exhibited slower growth and sulfate reduction rates in batch culture, and produced more H2 and an approximately 50% larger sulfur isotope effect, compared to the wild type. The magnitude of sulfur isotope fractionation in the CycA deletion strain, thus, increased due to the disrupted coupling of the carbon oxidation and sulfate reduction pathways. In continuous culture, wild-type D. vulgaris and the CycA mutant produced similar sulfur isotope effects, underscoring the influence of environmental conditions on the relative contribution of hydrogen cycling to the electron transport. The large sulfur isotope effects associated with the non-ideal stoichiometry of sulfate reduction in this study imply that simultaneous fermentation and sulfate reduction may be responsible for some of the large naturally-occurring sulfur isotope effects. Overall, mutant strains provide a powerful tool to test the effect of specific redox proteins and pathways on sulfur isotope fractionation. PMID:23805134

  14. Cross-Ontological Analytics: Combining Associative and Hierarchical Relations in the Gene Ontologies to Assess Gene Product Similarity

    SciTech Connect

    Posse, Christian; Sanfilippo, Antonio P.; Gopalan, Banu; Riensche, Roderick M.; Beagley, Nathaniel; Baddeley, Bob L.

    2006-05-28

    Gene and gene product similarity is a fundamental diagnostic measure in analyzing biological data and constructing predictive models for functional genomics. With the rising influence of the gene ontologies, two complementary approaches have emerged where the similarity between two genes/gene products is obtained by comparing gene ontology (GO) annotations associated with the gene/gene products. One approach captures GO-based similarity in terms of hierarchical relations within each gene ontology. The other approach identifies GO-based similarity in terms of associative relations across the three gene ontologies. We propose a novel methodology where the two approaches can be merged with ensuing benefits in coverage and accuracy.

  15. Age-related macular degeneration: Evidence of a major gene

    SciTech Connect

    Bhatt, S.; Warren, C.; Yang, H.

    1994-09-01

    Age-related macular degeneration is a major cause of blindness in developing countries. It remains a very poorly understood disorder. Although environmental and genetic factors have been implicated in its pathogenesis, none have been firmly implicated. The purpose of this study was to use pedigree analysis to evaluate the possible role of a major gene as a determinant of familial aggregation. Information was collected regarding occupation, smoking, sun exposure, associated medical problems and family history. 50 probands with age-related macular degeneration (ARMD) and 39 age, race and sex-matched controls were included in the study. In the ARMD group 15/50 (30%) of probands reported a positive family history; 22 out of 222 first degree relatives over age 60 were reported to be affected. In the control groups, none of the 138 first degree relatives over age 50 had a history of ARMD. This difference is statistically significant (p = 0.0003), indicating that genetic factors may play an important role in the pathogenesis of ARMD. In the ARMD group more siblings as compared to parents (16/127 vs. 5/82) were affected. 5/50 (10%) of the ARMD probands also gave a history of a second degree relative affected with ARMD, compared to none known among the relatives of controls. Data from 50 pedigrees were analyzed by complex segregation analysis under a class A regressive logistic model using the REGD program implemented in the SAGE package. Preliminary results allow rejection of a polygenic model and suggest there is a major gene for ARMD in these families. The inheritance model most compatible with the observed familial aggregation is autosomal recessive. In conclusion, these results are suggestive of a major gene effect in the etiology of ARMD. Identification of a major gene effect is a first step to further pursue linkage analysis and to search for the gene(s) involved in the causation of ARMD.

  16. Hepatitis-related hepatocellular carcinoma: Insights into cytokine gene polymorphisms

    PubMed Central

    Dondeti, Mahmoud Fathy; El-Maadawy, Eman Anwar; Talaat, Roba Mohamed

    2016-01-01

    Hepatocellular carcinoma (HCC) is a primary liver cancer, which is one of the most prevalent cancers among humans. Many factors are involved in the liver carcinogenesis as lifestyle and environmental factors. Hepatitis virus infections are now recognized as the chief etiology of HCC; however, the precise mechanism is still enigmatic till now. The inflammation triggered by the cytokine-mediated immune response, was reported to be the closest factor of HCC development. Cytokines are immunoregulatory proteins produced by immune cells, functioning as orchestrators of the immune response. Genes of cytokines and their receptors are known to be polymorphic, which give rise to variations in their genes. These variations have a great impact on the expression levels of the secreted cytokines. Therefore, cytokine gene polymorphisms are involved in the molecular mechanisms of several diseases. This piece of work aims to shed much light on the role of cytokine gene polymorphisms as genetic host factor in hepatitis related HCC. PMID:27570418

  17. Visually Relating Gene Expression and in vivo DNA Binding Data

    SciTech Connect

    Huang, Min-Yu; Mackey, Lester; Ker?,; nen, Soile V. E.; Weber, Gunther H.; Jordan, Michael I.; Knowles, David W.; Biggin, Mark D.; Hamann, Bernd

    2011-09-20

    Gene expression and in vivo DNA binding data provide important information for understanding gene regulatory networks: in vivo DNA binding data indicate genomic regions where transcription factors are bound, and expression data show the output resulting from this binding. Thus, there must be functional relationships between these two types of data. While visualization and data analysis tools exist for each data type alone, there is a lack of tools that can easily explore the relationship between them. We propose an approach that uses the average expression driven by multiple of ciscontrol regions to visually relate gene expression and in vivo DNA binding data. We demonstrate the utility of this tool with examples from the network controlling early Drosophila development. The results obtained support the idea that the level of occupancy of a transcription factor on DNA strongly determines the degree to which the factor regulates a target gene, and in some cases also controls whether the regulation is positive or negative.

  18. Comparative and functional analysis of cardiovascular-related genes

    SciTech Connect

    Cheng, Jan-Fang; Pennacchio, Len A.

    2003-09-01

    The ability to detect putative cis-regulatory elements in cardiovascular-related genes has been accelerated by the availability of genomic sequence data from numerous vertebrate species and the recent development of comparative genomic tools. This improvement is anticipated to lead to a better understanding of the complex regulatory architecture of cardiovascular (CV) genes and how genetic variants in these non-coding regions can potentially play a role in cardiovascular disease. This manuscript reviews a recently established database dedicated to the comparative sequence analysis of 250 human CV genes of known importance, 37 of which currently contain sequence comparison data for organisms beyond those of human, mouse and rat. These data have provided a glimpse into the variety of possible insights from deep vertebrate sequence comparisons and the identification of putative gene regulatory elements.

  19. Hepatitis-related hepatocellular carcinoma: Insights into cytokine gene polymorphisms.

    PubMed

    Dondeti, Mahmoud Fathy; El-Maadawy, Eman Anwar; Talaat, Roba Mohamed

    2016-08-14

    Hepatocellular carcinoma (HCC) is a primary liver cancer, which is one of the most prevalent cancers among humans. Many factors are involved in the liver carcinogenesis as lifestyle and environmental factors. Hepatitis virus infections are now recognized as the chief etiology of HCC; however, the precise mechanism is still enigmatic till now. The inflammation triggered by the cytokine-mediated immune response, was reported to be the closest factor of HCC development. Cytokines are immunoregulatory proteins produced by immune cells, functioning as orchestrators of the immune response. Genes of cytokines and their receptors are known to be polymorphic, which give rise to variations in their genes. These variations have a great impact on the expression levels of the secreted cytokines. Therefore, cytokine gene polymorphisms are involved in the molecular mechanisms of several diseases. This piece of work aims to shed much light on the role of cytokine gene polymorphisms as genetic host factor in hepatitis related HCC. PMID:27570418

  20. The Uptake Hydrogenase in the Unicellular Diazotrophic Cyanobacterium Cyanothece sp. Strain PCC 7822 Protects Nitrogenase from Oxygen Toxicity

    PubMed Central

    Zhang, Xiaohui; Sherman, Debra M.

    2014-01-01

    Cyanothece sp. strain PCC 7822 is a unicellular, diazotrophic cyanobacterium that can produce large quantities of H2 when grown diazotrophically. This strain is also capable of genetic manipulations and can represent a good model for improving H2 production from cyanobacteria. To this end, a knockout mutation was made in the hupL gene (ΔhupL), and we determined how this would affect the amount of H2 produced. The ΔhupL mutant demonstrated virtually no nitrogenase activity or H2 production when grown under N2-fixing conditions. To ensure that this mutation only affected the hupL gene, a complementation strain was constructed readily with wild-type properties; this indicated that the original insertion was only in hupL. The mutant had no uptake hydrogenase activity but had increased bidirectional hydrogenase (Hox) activity. Western blotting and immunocytochemistry under the electron microscope indicated that the mutant had neither HupL nor NifHDK, although the nif genes were transcribed. Interestingly, biochemical analysis demonstrated that both HupL and NifH could be membrane associated. The results indicated that the nif genes were transcribed but that NifHDK was either not translated or was translated but rapidly degraded. We hypothesized that the Nif proteins were made but were unusually susceptible to O2 damage. Thus, we grew the mutant cells under anaerobic conditions and found that they grew well under N2-fixing conditions. We conclude that in unicellular diazotrophs, like Cyanothece sp. strain PCC 7822, the HupLS complex helps remove oxygen from the nitrogenase, and that this is a more important function than merely oxidizing the H2 produced by the nitrogenase. PMID:24317398

  1. Detecting Horizontal Gene Transfer between Closely Related Taxa.

    PubMed

    Adato, Orit; Ninyo, Noga; Gophna, Uri; Snir, Sagi

    2015-10-01

    Horizontal gene transfer (HGT), the transfer of genetic material between organisms, is crucial for genetic innovation and the evolution of genome architecture. Existing HGT detection algorithms rely on a strong phylogenetic signal distinguishing the transferred sequence from ancestral (vertically derived) genes in its recipient genome. Detecting HGT between closely related species or strains is challenging, as the phylogenetic signal is usually weak and the nucleotide composition is normally nearly identical. Nevertheless, there is a great importance in detecting HGT between congeneric species or strains, especially in clinical microbiology, where understanding the emergence of new virulent and drug-resistant strains is crucial, and often time-sensitive. We developed a novel, self-contained technique named Near HGT, based on the synteny index, to measure the divergence of a gene from its native genomic environment and used it to identify candidate HGT events between closely related strains. The method confirms candidate transferred genes based on the constant relative mutability (CRM). Using CRM, the algorithm assigns a confidence score based on "unusual" sequence divergence. A gene exhibiting exceptional deviations according to both synteny and mutability criteria, is considered a validated HGT product. We first employed the technique to a set of three E. coli strains and detected several highly probable horizontally acquired genes. We then compared the method to existing HGT detection tools using a larger strain data set. When combined with additional approaches our new algorithm provides richer picture and brings us closer to the goal of detecting all newly acquired genes in a particular strain. PMID:26439115

  2. Hydrogen-producing microflora and Fe-Fe hydrogenase diversities in seaweed bed associated with marine hot springs of Kalianda, Indonesia.

    PubMed

    Xu, Shou-Ying; He, Pei-Qing; Dewi, Seswita-Zilda; Zhang, Xue-Lei; Ekowati, Chasanah; Liu, Tong-Jun; Huang, Xiao-Hang

    2013-05-01

    Microbial fermentation is a promising technology for hydrogen (H(2)) production. H(2) producers in marine geothermal environments are thermophilic and halotolerant. However, no one has surveyed an environment specifically for thermophilic bacteria that produce H(2) through Fe-Fe hydrogenases (H(2)ase). Using heterotrophic medium, several microflora from a seaweed bed associated with marine hot springs were enriched and analyzed for H(2) production. A H(2)-producing microflora was obtained from Sargassum sp., 16S rRNA genes and Fe-Fe H(2)ase diversities of this enrichment were also analyzed. Based on 16S rRNA genes analysis, 10 phylotypes were found in the H(2)-producing microflora showing 90.0-99.5 % identities to known species, and belonged to Clostridia, Gammaproteobacteria, and Bacillales. Clostridia were the most abundant group, and three Clostridia phylotypes were most related to known H(2) producers such as Anaerovorax odorimutans (94.0 % identity), Clostridium papyrosolvens (98.4 % identity), and Clostridium tepidiprofundi (93.1 % identity). For Fe-Fe H(2)ases, seven phylotypes were obtained, showing 63-97 % identities to known Fe-Fe H(2)ases, and fell into four distinct clusters. Phylotypes HW55-3 and HM55-1 belonged to thermophilic and salt-tolerant H(2)-producing Clostridia, Halothermothrix orenii-like Fe-Fe H(2)ases (80 % identity), and cellulolytic H(2)-producing Clostridia, C. papyrosolvens-like Fe-Fe H(2)ases (97 % identity), respectively. The results of both 16S rRNA genes and Fe-Fe H(2)ases surveys suggested that the thermophilic and halotolerant H(2)-producing microflora in seaweed bed of hot spring area represented previously unknown H(2) producers, and have potential application for H(2) production.

  3. Radical S-adenosyl-L-methionine chemistry in the synthesis of hydrogenase and nitrogenase metal cofactors.

    PubMed

    Byer, Amanda S; Shepard, Eric M; Peters, John W; Broderick, Joan B

    2015-02-13

    Nitrogenase, [FeFe]-hydrogenase, and [Fe]-hydrogenase enzymes perform catalysis at metal cofactors with biologically unusual non-protein ligands. The FeMo cofactor of nitrogenase has a MoFe7S9 cluster with a central carbon, whereas the H-cluster of [FeFe]-hydrogenase contains a 2Fe subcluster coordinated by cyanide and CO ligands as well as dithiomethylamine; the [Fe]-hydrogenase cofactor has CO and guanylylpyridinol ligands at a mononuclear iron site. Intriguingly, radical S-adenosyl-L-methionine enzymes are vital for the assembly of all three of these diverse cofactors. This minireview presents and discusses the current state of knowledge of the radical S-adenosylmethionine enzymes required for synthesis of these remarkable metal cofactors.

  4. Interaction of [FeFe]-Hydrogenases with Single-walled Carbon Nanotubes

    SciTech Connect

    Chang, D. S.; McDonald, T. J.; Kim, Y.-H.; Blackburn, J. L.; Heben, M. J.; King, P. W.

    2007-01-01

    Single-walled carbon nanotubes (SWNT) are promising candidates for use in energy conversion devices as an active photo-collecting elements, for dissociation of bound excitons and charge-transfer from photo-excited chromophores, or as molecular wires to transport charge. Hydrogenases are enzymes that efficiently catalyze the reduction of protons from a variety of electron donors to produce molecular hydrogen. Hydrogenases together with SWNT suggest a novel biohybrid material for direct conversion of sunlight into H{sub 2}. Here, we report changes in SWNT optical properties upon addition of recombinant [FeFe] hydrogenases from Clostridium acetobutylicum and Chlamydomonas reinhardtii. We find evidence that novel and stable charge-transfer complexes are formed under conditions of the hydrogenase catalytic turnover, providing spectroscopic handles for further study and application of this hybrid system.

  5. Interaction of [FeFe]-hydrogenases with single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Svedruzic Chang, Drazenka; McDonald, Timothy J.; Kim, Yong-Hyun; Blackburn, Jeffrey L.; Heben, Michael J.; King, Paul W.

    2007-09-01

    Single-walled carbon nanotubes (SWNT) are promising candidates for use in energy conversion devices as an active photo-collecting elements, for dissociation of bound excitons and charge-transfer from photo-excited chromophores, or as molecular wires to transport charge. Hydrogenases are enzymes that efficiently catalyze the reduction of protons from a variety of electron donors to produce molecular hydrogen. Hydrogenases together with SWNT suggest a novel biohybrid material for direct conversion of sunlight into H II. Here, we report changes in SWNT optical properties upon addition of recombinant [FeFe] hydrogenases from Clostridium acetobutylicum and Chlamydomonas reinhardtii. We find evidence that novel and stable charge-transfer complexes are formed under conditions of the hydrogenase catalytic turnover, providing spectroscopic handles for further study and application of this hybrid system.

  6. High presence/absence gene variability in defense-related gene clusters of Cucumis melo

    PubMed Central

    2013-01-01

    Background Changes in the copy number of DNA sequences are one of the main mechanisms generating genome variability in eukaryotes. These changes are often related to phenotypic effects such as genetic disorders or novel pathogen resistance. The increasing availability of genome sequences through the application of next-generation massive sequencing technologies has allowed the study of genomic polymorphisms at both the interspecific and intraspecific levels, thus helping to understand how species adapt to changing environments through genome variability. Results Data on gene presence/absence variation (PAV) in melon was obtained by resequencing a cultivated accession and an old-relative melon variety, and using previously obtained resequencing data from three other melon cultivars, among them DHL92, on which the current draft melon genome sequence is based. A total of 1,697 PAV events were detected, involving 4.4% of the predicted melon gene complement. In all, an average 1.5% of genes were absent from each analyzed cultivar as compared to the DHL92 reference genome. The most populated functional category among the 304 PAV genes of known function was that of stress response proteins (30% of all classified PAVs). Our results suggest that genes from multi-copy families are five times more likely to be affected by PAV than singleton genes. Also, the chance of genes present in the genome in tandem arrays being affected by PAV is double that of isolated genes, with PAV genes tending to be in longer clusters. The highest concentration of PAV events detected in the melon genome was found in a 1.1 Mb region of linkage group V, which also shows the highest density of melon stress-response genes. In particular, this region contains the longest continuous gene-containing PAV sequence so far identified in melon. Conclusions The first genome-wide report of PAV variation among several melon cultivars is presented here. Multi-copy and clustered genes, especially those with

  7. Catalytic mechanism of hydrogenase from Azotobacter vinelandii. Final technical report, August 1, 1994--July 31, 1997

    SciTech Connect

    Arp, D.J.

    1997-10-01

    This project is focused on investigations of the catalytic mechanism of the hydrogenase found in the aerobic, N{sub 2}-fixing microorganism Azotobacter vinelandii. This report summarizes the progress during the first two years of the current project and include the anticipated course of the research for the remaining year of the current project. Because the current proposal represents a change in direction, the authors also include a brief progress report of prior DOE-sponsored research dealing with hydrogenases.

  8. (Catalytic mechanism of hydrogenase from aerobic N sub 2 -fixing microorganisms)

    SciTech Connect

    Arp, D.J.

    1991-01-01

    The results of this DOE-sponsored project have contributed to our understanding of the catalytic mechanism of A. vinelandii hydrogenase. A group of inhibitors have been characterized. These provide information about the different types of redox clusters involved in catalysis and the roles of each. One group has already used acetylene in a study of three desulfovibrian hydrogenases and shown that only the NiFe hydrogenases are inhibited. We have characterized a number of spectral properties of A. vinelandii hydrogenase. The EPR signals associated with this hydrogenase in the reduced state are reminiscent of other NiFe dimeric hydrogenases such as A. eutrophus, but distinctly difference from others such as D. gigas and Chromatium vinosum. Thus, while the NiFe dimeric hydrogenases are now recognized as a large group of similar enzymes, there are differences in the spectral and catalytic properties which are not explained by their similar redox inventories, identical subunit structures, immunological cross reactivity and conserved sequences. The inhibitors we have characterized are also proving of value in the spectral characterizations. Surprisingly, we only see a significant EP signal attributable to Ni after the enzyme has been inactivated with O{sub 2} and then reduced (though not reactivated). No spectral perterbations (EPR or UV-V is) of active enzyme can be attributed to binding of H{sub 2}, even though H{sub 2} clearly binds to this form of the enzyme. Acetylene, which does not substantially perterb the EPR signal of active hydrogenase, does result in a new absorption envelope in the UV-V is spectrum. Overall, the results of this project have revealed the complex interactions of the redox clusters in catalysis through studies of inhibitor mechanisms and spectral properties. 14 refs., 9 figs.

  9. Photosynthetic electron partitioning between [FeFe]-hydrogenase and ferredoxin:NADP+-oxidoreductase (FNR) enzymes in vitro.

    PubMed

    Yacoby, Iftach; Pochekailov, Sergii; Toporik, Hila; Ghirardi, Maria L; King, Paul W; Zhang, Shuguang

    2011-06-01

    Photosynthetic water splitting, coupled to hydrogenase-catalyzed hydrogen production, is considered a promising clean, renewable source of energy. It is widely accepted that the oxygen sensitivity of hydrogen production, combined with competition between hydrogenases and NADPH-dependent carbon dioxide fixation are the main limitations for its commercialization. Here we provide evidence that, under the anaerobic conditions that support hydrogen production, there is a significant loss of photosynthetic electrons toward NADPH production in vitro. To elucidate the basis for competition, we bioengineered a ferredoxin-hydrogenase fusion and characterized hydrogen production kinetics in the presence of Fd, ferredoxin:NADP(+)-oxidoreductase (FNR), and NADP(+). Replacing the hydrogenase with a ferredoxin-hydrogenase fusion switched the bias of electron transfer from FNR to hydrogenase and resulted in an increased rate of hydrogen photoproduction. These results suggest a new direction for improvement of biohydrogen production and a means to further resolve the mechanisms that control partitioning of photosynthetic electron transport.

  10. Photosynthetic electron partitioning between [FeFe]-hydrogenase and ferredoxin:NADP+-oxidoreductase (FNR) enzymes in vitro.

    PubMed

    Yacoby, Iftach; Pochekailov, Sergii; Toporik, Hila; Ghirardi, Maria L; King, Paul W; Zhang, Shuguang

    2011-06-01

    Photosynthetic water splitting, coupled to hydrogenase-catalyzed hydrogen production, is considered a promising clean, renewable source of energy. It is widely accepted that the oxygen sensitivity of hydrogen production, combined with competition between hydrogenases and NADPH-dependent carbon dioxide fixation are the main limitations for its commercialization. Here we provide evidence that, under the anaerobic conditions that support hydrogen production, there is a significant loss of photosynthetic electrons toward NADPH production in vitro. To elucidate the basis for competition, we bioengineered a ferredoxin-hydrogenase fusion and characterized hydrogen production kinetics in the presence of Fd, ferredoxin:NADP(+)-oxidoreductase (FNR), and NADP(+). Replacing the hydrogenase with a ferredoxin-hydrogenase fusion switched the bias of electron transfer from FNR to hydrogenase and resulted in an increased rate of hydrogen photoproduction. These results suggest a new direction for improvement of biohydrogen production and a means to further resolve the mechanisms that control partitioning of photosynthetic electron transport. PMID:21606330

  11. Nuclear resonance vibrational spectroscopy reveals the FeS cluster composition and active site vibrational properties of an O2-tolerant NAD+-reducing [NiFe] hydrogenase

    DOE PAGESBeta

    Lauterbach, Lars; Wang, Hongxin; Horch, Marius; Gee, Leland B.; Yoda, Yoshitaka; Tanaka, Yoshihito; Zebger, Ingo; Lenz, Oliver; Cramer, Stephen P.

    2014-10-30

    Hydrogenases are complex metalloenzymes that catalyze the reversible splitting of molecular hydrogen into protons and electrons essentially without overpotential. The NAD+-reducing soluble hydrogenase (SH) from Ralstonia eutropha is capable of H2 conversion even in the presence of usually toxic dioxygen. The molecular details of the underlying reactions are largely unknown, mainly because of limited knowledge of the structure and function of the various metal cofactors present in the enzyme. Here, all iron-containing cofactors of the SH were investigated by 57Fe specific nuclear resonance vibrational spectroscopy (NRVS). Our data provide experimental evidence for one [2Fe2S] center and four [4Fe4S] clusters, whichmore » is consistent with the amino acid sequence composition. Only the [2Fe2S] cluster and one of the four [4Fe4S] clusters were reduced upon incubation of the SH with NADH. This finding explains the discrepancy between the large number of FeS clusters and the small amount of FeS cluster-related signals as detected by electron paramagnetic resonance spectroscopic analysis of several NAD+-reducing hydrogenases. For the first time, Fe–CO and Fe–CN modes derived from the [NiFe] active site could be distinguished by NRVS through selective 13C labeling of the CO ligand. This strategy also revealed the molecular coordinates that dominate the individual Fe–CO modes. The present approach explores the complex vibrational signature of the Fe–S clusters and the hydrogenase active site, thereby showing that NRVS represents a powerful tool for the elucidation of complex biocatalysts containing multiple cofactors.« less

  12. Impact of the iron-sulfur cluster proximal to the active site on the catalytic function of an O2-tolerant NAD(+)-reducing [NiFe]-hydrogenase.

    PubMed

    Karstens, Katja; Wahlefeld, Stefan; Horch, Marius; Grunzel, Miriam; Lauterbach, Lars; Lendzian, Friedhelm; Zebger, Ingo; Lenz, Oliver

    2015-01-20

    The soluble NAD(+)-reducing hydrogenase (SH) from Ralstonia eutropha H16 belongs to the O2-tolerant subtype of pyridine nucleotide-dependent [NiFe]-hydrogenases. To identify molecular determinants for the O2 tolerance of this enzyme, we introduced single amino acids exchanges in the SH small hydrogenase subunit. The resulting mutant strains and proteins were investigated with respect to their physiological, biochemical, and spectroscopic properties. Replacement of the four invariant conserved cysteine residues, Cys41, Cys44, Cys113, and Cys179, led to unstable protein, strongly supporting their involvement in the coordination of the iron-sulfur cluster proximal to the catalytic [NiFe] center. The Cys41Ser exchange, however, resulted in an SH variant that displayed up to 10% of wild-type activity, suggesting that the coordinating role of Cys41 might be partly substituted by the nearby Cys39 residue, which is present only in O2-tolerant pyridine nucleotide-dependent [NiFe]-hydrogenases. Indeed, SH variants carrying glycine, alanine, or serine in place of Cys39 showed increased O2 sensitivity compared to that of the wild-type enzyme. Substitution of further amino acids typical for O2-tolerant SH representatives did not greatly affect the H2-oxidizing activity in the presence of O2. Remarkably, all mutant enzymes investigated by electron paramagnetic resonance spectroscopy did not reveal significant spectral changes in relation to wild-type SH, showing that the proximal iron-sulfur cluster does not contribute to the wild-type spectrum. Interestingly, exchange of Trp42 by serine resulted in a completely redox-inactive [NiFe] site, as revealed by infrared spectroscopy and H2/D(+) exchange experiments. The possible role of this residue in electron and/or proton transfer is discussed.

  13. Gene-environment interactions of circadian-related genes for cardiometabolic traits

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Common circadian-related gene variants associate with increased risk for metabolic alterations including type 2 diabetes. However, little is known about whether diet and sleep could modify associations between circadian-related variants (CLOCK-rs1801260, CRY2-rs11605924, MTNR1B-rs1387153, MTNR1B-rs1...

  14. Studies of Hybrid Nano-Bio-System: Single-Walled Carbon Nanotubes and Hydrogenase

    SciTech Connect

    Svedruzic-Chang, D.; Blackburn, J. L.; McDonald, T. J.; Heben, M. J.; King, P. W.

    2008-01-01

    We have examined changes in single-walled carbon nanotubes (SWNT) optical signals upon addition of recombinant [FeFe] hydrogenases from Clostridium acetobutylicum or Chlamydomonas reinhardtii. We found evidence that novel and stable charge-transfer complexes are formed only under conditions of hydrogenase catalytic turnover. Formation of the complex sensitizes the nanotubes to the proton-to-hydrogen redox half-reaction. Thus, the experimental potential can be altered by changing the pH or molecular hydrogen concentration. In the presence of molecular hydrogen, hydrogenase mediates electron injection into the conduction band of semiconducting SWNT, which was observed as a quenching of the photoluminescence signals. Here, we will present recent Raman studies, which revealed that SWNTs in a complex with hydrogenase may undergo either oxidation or reduction, depending on the electronic structure of the SWNT and the oxidation state of the enzyme. In addition, we will describe our efforts to prepare stable, solubilized SWNT/hydrogenase complexes in the absence of detergent. This work shows that SWNT/hydrogenase complexes have potential applications as a component of an energy conversion device.

  15. Integration of an [FeFe]-hydrogenase into the anaerobic metabolism of Escherichia coli

    PubMed Central

    Kelly, Ciarán L.; Pinske, Constanze; Murphy, Bonnie J.; Parkin, Alison; Armstrong, Fraser; Palmer, Tracy; Sargent, Frank

    2015-01-01

    Biohydrogen is a potentially useful product of microbial energy metabolism. One approach to engineering biohydrogen production in bacteria is the production of non-native hydrogenase activity in a host cell, for example Escherichia coli. In some microbes, hydrogenase enzymes are linked directly to central metabolism via diaphorase enzymes that utilise NAD+/NADH cofactors. In this work, it was hypothesised that heterologous production of an NAD+/NADH-linked hydrogenase could connect hydrogen production in an E. coli host directly to its central metabolism. To test this, a synthetic operon was designed and characterised encoding an apparently NADH-dependent, hydrogen-evolving [FeFe]-hydrogenase from Caldanaerobacter subterranus. The synthetic operon was stably integrated into the E. coli chromosome and shown to produce an active hydrogenase, however no H2 production was observed. Subsequently, it was found that heterologous co-production of a pyruvate::ferredoxin oxidoreductase and ferredoxin from Thermotoga maritima was found to be essential to drive H2 production by this system. This work provides genetic evidence that the Ca.subterranus [FeFe]-hydrogenase could be operating in vivo as an electron-confurcating enzyme. PMID:26839796

  16. Macular xanthophylls, lipoprotein-related genes, and age-related macular degeneration1234

    PubMed Central

    Koo, Euna; Neuringer, Martha; SanGiovanni, John Paul

    2014-01-01

    Plant-based macular xanthophylls (MXs; lutein and zeaxanthin) and the lutein metabolite meso-zeaxanthin are the major constituents of macular pigment, a compound concentrated in retinal areas that are responsible for fine-feature visual sensation. There is an unmet need to examine the genetics of factors influencing regulatory mechanisms and metabolic fates of these 3 MXs because they are linked to processes implicated in the pathogenesis of age-related macular degeneration (AMD). In this work we provide an overview of evidence supporting a molecular basis for AMD-MX associations as they may relate to DNA sequence variation in AMD- and lipoprotein-related genes. We recognize a number of emerging research opportunities, barriers, knowledge gaps, and tools offering promise for meaningful investigation and inference in the field. Overviews on AMD- and high-density lipoprotein (HDL)–related genes encoding receptors, transporters, and enzymes affecting or affected by MXs are followed with information on localization of products from these genes to retinal cell types manifesting AMD-related pathophysiology. Evidence on the relation of each gene or gene product with retinal MX response to nutrient intake is discussed. This information is followed by a review of results from mechanistic studies testing gene-disease relations. We then present findings on relations of AMD with DNA sequence variants in MX-associated genes. Our conclusion is that AMD-associated DNA variants that influence the actions and metabolic fates of HDL system constituents should be examined further for concomitant influence on MX absorption, retinal tissue responses to MX intake, and the capacity to modify MX-associated factors and processes implicated in AMD pathogenesis. PMID:24829491

  17. [FeFe] hydrogenases and their evolution: a genomic perspective.

    PubMed

    Meyer, J

    2007-05-01

    Most hydrogenases (H2ases), the enzymes that produce or oxidize dihydrogen, possess dimetallic active sites and belong to either one of two phylogenetically distinct classes, the [NiFe] and the [FeFe] H2ases. These families of H2ases share a number of similarities regarding active site structure and reaction mechanism, as a result of convergent evolution. They are otherwise alien to each other, in particular with respect to protein sequence and structure, maturation mechanisms, and distribution among the realms of life. One of the interesting features of [FeFe] H2ases is their occurrence in anaerobic bacteria, anaerobic protists, and mitochondriate eukaryotes. They thus have the potential to report on important evolutionary events, including transitions from the prokaryote to the eukaryote lifestyle. Genome sequences yield a variety of [FeFe] H2ase sequences that have been implemented to shed light on the evolution of these proteins and their host organisms.

  18. Gene expression profiles of autophagy-related genes in multiple sclerosis.

    PubMed

    Igci, Mehri; Baysan, Mehmet; Yigiter, Remzi; Ulasli, Mustafa; Geyik, Sirma; Bayraktar, Recep; Bozgeyik, İbrahim; Bozgeyik, Esra; Bayram, Ali; Cakmak, Ecir Ali

    2016-08-15

    Multiple sclerosis (MS) is an imflammatory disease of central nervous system caused by genetic and environmental factors that remain largely unknown. Autophagy is the process of degradation and recycling of damaged cytoplasmic organelles, macromolecular aggregates, and long-lived proteins. Malfunction of autophagy contributes to the pathogenesis of neurological diseases, and autophagy genes may modulate the T cell survival. We aimed to examine the expression levels of autophagy-related genes. The blood samples of 95 unrelated patients (aged 17-65years, 37 male, 58 female) diagnosed as MS and 95 healthy controls were used to extract the RNA samples. After conversion to single stranded cDNA using polyT priming: the targeted genes were pre-amplified, and 96×78 (samples×primers) qRT-PCR reactions were performed for each primer pair on each sample on a 96.96 array of Fluidigm BioMark™. Compared to age- and sex-matched controls, gene expression levels of ATG16L2, ATG9A, BCL2, FAS, GAA, HGS, PIK3R1, RAB24, RGS19, ULK1, FOXO1, HTT were significantly altered (false discovery rate<0.05). Thus, altered expression levels of several autophagy related genes may affect protein levels, which in turn would influence the activity of autophagy, or most probably, those genes might be acting independent of autophagy and contributing to MS pathogenesis as risk factors. The indeterminate genetic causes leading to alterations in gene expressions require further analysis. PMID:27125224

  19. Gene expression profiles of autophagy-related genes in multiple sclerosis.

    PubMed

    Igci, Mehri; Baysan, Mehmet; Yigiter, Remzi; Ulasli, Mustafa; Geyik, Sirma; Bayraktar, Recep; Bozgeyik, İbrahim; Bozgeyik, Esra; Bayram, Ali; Cakmak, Ecir Ali

    2016-08-15

    Multiple sclerosis (MS) is an imflammatory disease of central nervous system caused by genetic and environmental factors that remain largely unknown. Autophagy is the process of degradation and recycling of damaged cytoplasmic organelles, macromolecular aggregates, and long-lived proteins. Malfunction of autophagy contributes to the pathogenesis of neurological diseases, and autophagy genes may modulate the T cell survival. We aimed to examine the expression levels of autophagy-related genes. The blood samples of 95 unrelated patients (aged 17-65years, 37 male, 58 female) diagnosed as MS and 95 healthy controls were used to extract the RNA samples. After conversion to single stranded cDNA using polyT priming: the targeted genes were pre-amplified, and 96×78 (samples×primers) qRT-PCR reactions were performed for each primer pair on each sample on a 96.96 array of Fluidigm BioMark™. Compared to age- and sex-matched controls, gene expression levels of ATG16L2, ATG9A, BCL2, FAS, GAA, HGS, PIK3R1, RAB24, RGS19, ULK1, FOXO1, HTT were significantly altered (false discovery rate<0.05). Thus, altered expression levels of several autophagy related genes may affect protein levels, which in turn would influence the activity of autophagy, or most probably, those genes might be acting independent of autophagy and contributing to MS pathogenesis as risk factors. The indeterminate genetic causes leading to alterations in gene expressions require further analysis.

  20. The evolution of cancer-related genes in hominoids.

    PubMed

    Kang, Lin; Michalak, Pawel

    2015-01-01

    The evolution of cancer suppression is essential for the maintenance of multicellularity. The lack of correlation between body size and cancer risk across species, known as Peto's paradox, suggests that genetic variation in cancer resistance is sufficient to compensate for increases of cell numbers in bigger animals. To assess evolutionary dynamics of cancer-related genes, we analyzed Ka, Ks,and Ka/Ks values in 120 oncogenes and tumor suppressor genes (TSG) among seven hominoid species, including two extinct species, Neanderthal and Denisovan. Ka/Ks of tumor suppressor genes tended to be higher relative to that of oncogenes, consistent with relaxed purifying selection acting on the former. Ka/Ks values were positively correlated with TSG scores, but negatively correlated with oncogene scores, suggesting opposing selection pressures operating on the two groups of cancer-related genes. Additionally, we found 108 species-divergent substitutions that were prevalent germline genotypes in some species but in humans appeared only as somatic cancerous mutations. Better understanding the resistance to cancer may lead to new methods of cancer prevention in humans.

  1. A widespread class of reverse transcriptase-related cellular genes.

    PubMed

    Gladyshev, Eugene A; Arkhipova, Irina R

    2011-12-20

    Reverse transcriptases (RTs) polymerize DNA on RNA templates. They fall into several structurally related but distinct classes and form an assemblage of RT-like enzymes that, in addition to RTs, also includes certain viral RNA-dependent RNA polymerases (RdRP) synthesizing RNA on RNA templates. It is generally believed that most RT-like enzymes originate from retrotransposons or viruses and have no specific function in the host cell, with telomerases being the only notable exception. Here we report on the discovery and properties of a unique class of RT-related cellular genes collectively named rvt. We present evidence that rvts are not components of retrotransposons or viruses, but single-copy genes with a characteristic domain structure that may contain introns in evolutionarily conserved positions, occur in syntenic regions, and evolve under purifying selection. These genes can be found in all major taxonomic groups including protists, fungi, animals, plants, and even bacteria, although they exhibit patchy phylogenetic distribution in each kingdom. We also show that the RVT protein purified from one of its natural hosts, Neurospora crassa, exists in a multimeric form and has the ability to polymerize NTPs as well as dNTPs in vitro, with a strong preference for NTPs, using Mn(2+) as a cofactor. The existence of a previously unknown class of single-copy RT-related genes calls for reevaluation of the current views on evolution and functional roles of RNA-dependent polymerases in living cells.

  2. A widespread class of reverse transcriptase-related cellular genes

    PubMed Central

    Gladyshev, Eugene A.; Arkhipova, Irina R.

    2011-01-01

    Reverse transcriptases (RTs) polymerize DNA on RNA templates. They fall into several structurally related but distinct classes and form an assemblage of RT-like enzymes that, in addition to RTs, also includes certain viral RNA-dependent RNA polymerases (RdRP) synthesizing RNA on RNA templates. It is generally believed that most RT-like enzymes originate from retrotransposons or viruses and have no specific function in the host cell, with telomerases being the only notable exception. Here we report on the discovery and properties of a unique class of RT-related cellular genes collectively named rvt. We present evidence that rvts are not components of retrotransposons or viruses, but single-copy genes with a characteristic domain structure that may contain introns in evolutionarily conserved positions, occur in syntenic regions, and evolve under purifying selection. These genes can be found in all major taxonomic groups including protists, fungi, animals, plants, and even bacteria, although they exhibit patchy phylogenetic distribution in each kingdom. We also show that the RVT protein purified from one of its natural hosts, Neurospora crassa, exists in a multimeric form and has the ability to polymerize NTPs as well as dNTPs in vitro, with a strong preference for NTPs, using Mn2+ as a cofactor. The existence of a previously unknown class of single-copy RT-related genes calls for reevaluation of the current views on evolution and functional roles of RNA-dependent polymerases in living cells. PMID:21876125

  3. Titanium nanotubes activate genes related to bone formation in vitro

    PubMed Central

    Pozio, Alfonso; Palmieri, Annalisa; Girardi, Ambra; Cura, Francesca; Carinci, Francesco

    2012-01-01

    Background: Titanium is used worldwide to make osseointegrable devices, thanks to its favorable characteristics as mechanical proprieties and biocompatibility, demonstrated by in vivo studies with animal models and clinical trials over a forty-year period. However, the exact genetic effect of the titanium layer on cells is still not well characterized. Materials and Methods: To investigate how titanium nanotubes stimulate osteoblasts differentiation and proliferation, some osteoblast genes (SP7, RUNX2, COL3A1, COL1A1, ALPL, SPP1 and FOSL1) were analyzed by quantitative Real Time RT- PCR. Results: After 15 days, osteoblasts cultivated on titanium naotube showed the up-regulation of bone related genes SP7, ENG, FOSL1 and SPP1 and the down-regulation of RUNX2, COL3A1, COL1A1, and ALPL. After 30 days of treatment, the bone related genes SP7, ENG, FOSL1 and RUNX2 were up-regulated while COL3A1, COL1A1, ALPL and SPP1 were down-regulated. Conclusions: Our results, demonstrates that titanium nanotubes can lead to osteoblast differentiation and extracellular matrix deposition and mineralization in dental pulp stem cells by the activation of osteoblast related genes SPP1, FOSL1 and RUNX2. PMID:23814577

  4. Combinatorial gene regulation by modulation of relative pulse timing

    PubMed Central

    Lin, Yihan; Sohn, Chang Ho; Dalal, Chiraj K.; Cai, Long; Elowitz, Michael B.

    2015-01-01

    Studies of individual living cells have revealed that many transcription factors activate in dynamic, and often stochastic, pulses within the same cell. However, it has remained unclear whether cells might modulate the relative timing of these pulses to control gene expression. Here, using quantitative single-cell time-lapse imaging of Saccharomyces cerevisiae, we show that the pulsatile transcription factors Msn2 and Mig1 combinatorially regulate their target genes through modulation of their relative pulse timing. The activator Msn2 and repressor Mig1 pulsed in either a temporally overlapping or non-overlapping manner during their transient response to different inputs, with only the non-overlapping dynamics efficiently activating target gene expression. Similarly, under constant environmental conditions, where Msn2 and Mig1 exhibit sporadic pulsing, glucose concentration modulated the temporal overlap between pulses of the two factors. Together, these results reveal a time-based mode of combinatorial gene regulation. Regulation through relative signal timing is common in engineering and neurobiology, and these results suggest that it could also function broadly within the signaling and regulatory systems of the cell. PMID:26466562

  5. Decolorization and degradation of textile dyes with biosulfidogenic hydrogenases.

    PubMed

    Mutambanengwe, C C Z; Togo, C A; Whiteley, C G

    2007-01-01

    Successful decolorization of azo dyes (Orange II, Amido Black 10, Reactive Black 5, and Reactive Red 120) and industrial textile dye influents and effluents with sulfate-reducing bacteria from within a biosulfidogenic reactor was achieved with decolorizations ranging from 96% to 49% over 144 h. Concomitant with the decrease in absorbance of the dye in the visible region (480-620 nm) was an increase in the absorbance at 280 nm, over 48 h, suggesting an increase in concentration of single aromatic amines. With an extended period of time there was a subsequent decrease in the absorbance at 280 nm indicating that the aromatic amines had been degraded. The anthraquinone dye, Reactive Blue 2, remained unchanged after 144 h of incubation in the biosulfidogenic reactor and was only rapidly decolored at 192 h, implying that certain factors are induced in the reactor to break down this non-azo dye. The fastest decolorization/degradation rates and highest hydrogenase enzyme production were observed with Orange II, while the slowest decolorization/degradation rate and least enzyme production were with Reactive Blue 2, suggesting that these processes are controlled, to a certain degree, by an enzymatic mechanism. With sulfate-reducing bacteria that had been cultured on a lactate medium, there was complete decolorization of both authentic dyes and industrial influents and effluents as monitored by the decrease of absorbance in the visible region (480-620 nm). There was, however, very little breakdown of the single aromatic compounds as the absorbance at 280 nm remained fairly significant. This supports the suggestion that, within the biosulfidogenic reactor, there are factors other than the identified hydrogenases that are responsible for degradation of the aromatic compounds.

  6. Gene-Diet Interactions in Age-Related Macular Degeneration.

    PubMed

    Rowan, Sheldon; Taylor, Allen

    2016-01-01

    Age-related macular degeneration (AMD) is a prevalent blinding disease, accounting for roughly 50 % of blindness in developed nations. Very significant advances have been made in terms of discovering genetic susceptibilities to AMD as well as dietary risk factors. To date, nutritional supplementation is the only available treatment option for the dry form of the disease known to slow progression of AMD. Despite an excellent understanding of genes and nutrition in AMD, there is remarkably little known about gene-diet interactions that may identify efficacious approaches to treat individuals. This review will summarize our current understanding of gene-diet interactions in AMD with a focus on animal models and human epidemiological studies.

  7. CO and CN- syntheses by [FeFe]-hydrogenase maturase HydG are catalytically differentiated events.

    PubMed

    Pagnier, Adrien; Martin, Lydie; Zeppieri, Laura; Nicolet, Yvain; Fontecilla-Camps, Juan C

    2016-01-01

    The synthesis and assembly of the active site [FeFe] unit of [FeFe]-hydrogenases require at least three maturases. The radical S-adenosyl-l-methionine HydG, the best characterized of these proteins, is responsible for the synthesis of the hydrogenase CO and CN(-) ligands from tyrosine-derived dehydroglycine (DHG). We speculated that CN(-) and the CO precursor (-):CO2H may be generated through an elimination reaction. We tested this hypothesis with both wild type and HydG variants defective in second iron-sulfur cluster coordination by measuring the in vitro production of CO, CN(-), and (-):CO2H-derived formate. We indeed observed formate production under these conditions. We conclude that HydG is a multifunctional enzyme that produces DHG, CN(-), and CO at three well-differentiated catalytic sites. We also speculate that homocysteine, cysteine, or a related ligand could be involved in Fe(CO)x(CN)y transfer to the HydF carrier/scaffold. PMID:26699472

  8. CO and CN− syntheses by [FeFe]-hydrogenase maturase HydG are catalytically differentiated events

    PubMed Central

    Pagnier, Adrien; Martin, Lydie; Zeppieri, Laura; Nicolet, Yvain; Fontecilla-Camps, Juan C.

    2016-01-01

    The synthesis and assembly of the active site [FeFe] unit of [FeFe]-hydrogenases require at least three maturases. The radical S-adenosyl-l-methionine HydG, the best characterized of these proteins, is responsible for the synthesis of the hydrogenase CO and CN− ligands from tyrosine-derived dehydroglycine (DHG). We speculated that CN− and the CO precursor −:CO2H may be generated through an elimination reaction. We tested this hypothesis with both wild type and HydG variants defective in second iron-sulfur cluster coordination by measuring the in vitro production of CO, CN−, and −:CO2H-derived formate. We indeed observed formate production under these conditions. We conclude that HydG is a multifunctional enzyme that produces DHG, CN−, and CO at three well-differentiated catalytic sites. We also speculate that homocysteine, cysteine, or a related ligand could be involved in Fe(CO)x(CN)y transfer to the HydF carrier/scaffold. PMID:26699472

  9. A patient with PMP22-related hereditary neuropathy and DBH-gene-related dysautonomia.

    PubMed

    Bartoletti-Stella, Anna; Chiaro, Giacomo; Calandra-Buonaura, Giovanna; Contin, Manuela; Scaglione, Cesa; Barletta, Giorgio; Cecere, Annagrazia; Garagnani, Paolo; Tieri, Paolo; Ferrarini, Alberto; Piras, Silvia; Franceschi, Claudio; Delledonne, Massimo; Cortelli, Pietro; Capellari, Sabina

    2015-10-01

    Recurrent focal neuropathy with liability to pressure palsies is a relatively frequent autosomal-dominant demyelinating neuropathy linked to peripheral myelin protein 22 (PMP22) gene deletions. The combination of PMP22 gene mutations with other genetic variants is known to cause a more severe phenotype than expected. We present the case of a patient with severe orthostatic hypotension since 12 years of age, who inherited a PMP22 gene deletion from his father. Genetic double trouble was suspected because of selective sympathetic autonomic disturbances. Through exome-sequencing analysis, we identified two novel mutations in the dopamine beta hydroxylase gene. Moreover, with interactome analysis, we excluded a further influence on the origin of the disease by variants in other genes. This case increases the number of unique patients presenting with dopamine-β-hydroxylase deficiency and of cases with genetically proven double trouble. Finding the right, complete diagnosis is crucial to obtain adequate medical care and appropriate genetic counseling. PMID:26410747

  10. Transcriptional regulation of genes related to progesterone production.

    PubMed

    Mizutani, Tetsuya; Ishikane, Shin; Kawabe, Shinya; Umezawa, Akihiro; Miyamoto, Kaoru

    2015-01-01

    Steroid hormones are synthesized from cholesterol in various tissues, mainly in the adrenal glands and gonads. Because these lipid-soluble steroid hormones immediately diffuse through the cells in which they are produced, their secretion directly reflects the activity of the genes related to their production. Progesterone is important not only for luteinization and maintenance of pregnancy, but also as a substrate for most other steroids. Steroidogenic acute regulatory protein (STAR), cytochrome P450 cholesterol side-chain cleavage enzyme (P450scc), and 3β-hydroxysteroid dehydrogenase/Δ(5)-Δ(4) isomerase (3β-HSD) are well-known proteins essential for progesterone production. In addition to them, glutathione S-transferase A1-1 and A3-3 are shown to exert Δ(5)-Δ(4) isomerization activity to produce progesterone in a cooperative fashion with 3β-HSD. 5-Aminolevulinic acid synthase 1, ferredoxin 1, and ferredoxin reductase also play a role in steroidogenesis as accessory factors. Members of the nuclear receptor 5A (NR5A) family (steroidogenic factor 1 and liver receptor homolog 1) play a crucial role in the transcriptional regulation of these genes. The NR5A family activates these genes by binding to NR5A responsive elements present within their promoter regions, as well as to the elements far from their promoters. In addition, various NR5A-interacting proteins including peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), nuclear receptor subfamily 0, group B, member 1 (DAX-1), and CCAAT/enhancer-binding proteins (C/EBP) are involved in the transcription of NR5A target genes and regulate the transcription either positively or negatively under both basal and tropic hormone-stimulated conditions. In this review, we describe the transcriptional regulation of genes related to progesterone production. PMID:26135521

  11. Hydrogenase Activity of Mineral-Associated and Suspended Populations of Desulfovibrio desulfuricans Essex 6

    SciTech Connect

    C.L. Reardon; T.S. Magnuson; E.S. Boyd; W.D. Leavitt; D.W. Reed; G.G. Geesey

    2014-02-01

    The interactions between sulfate-reducing microorganisms and iron oxides influence a number of important redox-sensitive biogeochemical processes including the formation of iron sulfides. Enzymes, such as hydrogenase which catalyze the reversible oxidation of molecular hydrogen, are known to mediate electron transfer to metals and may contribute to the formation and speciation of ferrous sulfides formed at the cell–mineral interface. In the present study, we compared the whole cell hydrogenase activity of Desulfovibrio desulfuricans strain Essex 6 growing as biofilms on hematite (hematite-associated) or as suspended populations using different metabolic pathways. Hematite-associated cells exhibited significantly greater hydrogenase activity than suspended populations during sulfate respiration but not during pyruvate fermentation. The enhanced activity of the hematite-associated, sulfate-grown cells appears to be dependent on iron availability rather than a general response to surface attachment since the activity of glass-associated cells did not differ from that of suspended populations. Hydrogenase activity of pyruvate-fermenting cells was stimulated by addition of iron as soluble Fe(II)Cl2 and, in the absence of added iron, both sulfate-reducing and pyruvate-fermenting cells displayed similar rates of hydrogenase activity. These data suggest that iron exerts a stronger influence on whole cell hydrogenase activity than either metabolic pathway or mode of growth. The location of hydrogenase to the cell envelope and the enhanced activity at the hematite surface in sulfate-reducing cells may influence the redox conditions that control the species of iron sulfides on the mineral surface.

  12. Expression and interaction analysis of Arabidopsis Skp1-related genes.

    PubMed

    Takahashi, Naoki; Kuroda, Hirofumi; Kuromori, Takashi; Hirayama, Takashi; Seki, Motoaki; Shinozaki, Kazuo; Shimada, Hiroaki; Matsui, Minami

    2004-01-01

    Specific protein degradation has been observed in several aspects of development and differentiation in many organisms. One example of such proteolysis is regulated by protein polyubiquitination that is promoted by the SCF complex consisting of Skp1, cullin, and an F-box protein. We examined the activities of the Arabidopsis Skp1-related proteins (ASKs). Among 19 annotated ASK genes, we isolated 16 of the corresponding cDNAs (ASK1, 2, 3, 4, 7, 8, 9, 10, 11, 12, 13, 14, 16, 17, 18, 19), and examined their gene products for interactions with 24 representatives of F-box proteins carrying various classes of the C-terminal domains using the yeast two-hybrid system. As a result, we found diverse binding specificities: ASK1, ASK2, ASK11 and ASK12 interacted well with COI1, FKF1, UFO-like protein, LRR-containing F-box proteins, and other F-box proteins with unknown C-terminal motifs. We also observed specific interaction between F-box proteins and ASK3, ASK9, ASK13, ASK14, ASK16 and ASK18. In contrast, we detected no interaction between any of the 12 ASK proteins and F-box proteins containing CRFA, CRFB or CRFC domains. Both histochemical and RT-PCR analysis of eight ASK genes expression revealed unique expression patterns for the respective genes. PMID:14749489

  13. Relating protein adduction to gene expression changes: a systems approach

    PubMed Central

    Zhang, Bing; Shi, Zhiao; Duncan, Dexter T; Prodduturi, Naresh; Marnett, Lawrence J; Liebler, Daniel C

    2013-01-01

    Modification of proteins by reactive electrophiles such as the 4-hydroxy-2-nonenal (HNE) plays a critical role in oxidant-associated human diseases. However, little is known about protein adduction and the mechanism by which protein damage elicits adaptive effects and toxicity. We developed a systems approach for relating protein adduction to gene expression changes through the integration of protein adduction, gene expression, protein-DNA interaction, and protein-protein interaction data. Using a random walk strategy, we expanded a list of responsive transcription factors inferred from gene expression studies to upstream signaling networks, which in turn allowed overlaying protein adduction data on the network for the prediction of stress sensors and their associated regulatory mechanisms. We demonstrated the general applicability of transcription factor-based signaling network inference using 103 known pathways. Applying our workflow on gene expression and protein adduction data from HNE-treatment not only rediscovered known mechanisms of electrophile stress but also generated novel hypotheses regarding protein damage sensors. Although developed for analyzing protein adduction data, the framework can be easily adapted for phosphoproteomics and other types of protein modification data. PMID:21594272

  14. Unification of [FeFe]-hydrogenases into three structural and functional groups

    DOE PAGESBeta

    Poudel, Saroj; Tokmina-Lukaszewska, Monika; Colman, Daniel R.; Refai, Mohammed; Schut, Gerrit J.; King, Paul W.; Maness, Pin-Ching; Adams, Michael W. W.; Peters, John W.; Bothner, Brian; et al

    2016-05-27

    [FeFe]-hydrogenases (Hyd) are structurally diverse enzymes that catalyze the reversible oxidation of hydrogen (H2). Recent biochemical data demonstrate new functional roles for these enzymes, including those that function in electron bifurcation where an exergonic reaction is coupled with an endergonic reaction to drive the reversible oxidation/production of H2. To identify the structural determinants that underpin differences in enzyme functionality, a total of 714 homologous sequences of the catalytic subunit, HydA, were compiled. Bioinformatics approaches informed by biochemical data were then used to characterize differences in inferred quaternary structure, HydA active site protein environment, accessory iron-sulfur clusters in HydA, and regulatorymore » proteins encoded in HydA gene neighborhoods. HydA homologs were clustered into one of three classification groups, Group 1 (G1), Group 2 (G2), and Group 3 (G3). G1 enzymes were predicted to be monomeric while those in G2 and G3 were predicted to be multimeric and include HydB, HydC (G2/G3) and HydD (G3) subunits. Variation in the HydA active site and accessory iron-sulfur clusters did not vary by group type. Group-specific regulatory genes were identified in the gene neighborhoods of both G2 and G3 Hyd. Analyses of purified G2 and G3 enzymes by mass spectrometry strongly suggests that they are post-translationally modified by phosphorylation. In conclusion, these results suggest that bifurcation capability is dictated primarily by the presence of both HydB and HydC in Hyd complexes, rather than by variation in HydA.« less

  15. Molecular cloning of allelopathy related genes and their relation to HHO in Eupatorium adenophorum.

    PubMed

    Guo, Huiming; Pei, Xixiang; Wan, Fanghao; Cheng, Hongmei

    2011-10-01

    In this study, conserved sequence regions of HMGR, DXR, and CHS (encoding 3-hydroxy-3-methylglutaryl-CoA reductase, 1-deoxyxylulose-5-phosphate reductoisomerase and chalcone synthase, respectively) were amplified by reverse transcriptase (RT)-PCR from Eupatorium adenophorum. Quantitative real-time PCR showed that the expression of CHS was related to the level of HHO, an allelochemical isolated from E. adenophorum. Semi-quantitative RT-PCR showed that there was no significant difference in expression of genes among three different tissues, except for CHS. Southern blotting indicated that at least three CHS genes are present in the E. adenophorum genome. A full-length cDNA from CHS genes (named EaCHS1, GenBank ID: FJ913888) was cloned. The 1,455 bp cDNA contained an open reading frame (1,206 bp) encoding a protein of 401 amino acids. Preliminary bioinformatics analysis of EaCHS1 revealed that EaCHS1 was a member of CHS family, the subcellular localization predicted that EaCHS1 was a cytoplasmic protein. To the best of our knowledge, this is the first report of conserved sequences of these genes and of a full-length EaCHS1 gene in E. adenophorum. The results indicated that CHS gene is related to allelopathy of E. adenophorum.

  16. Impact of obesity-related genes in Spanish population

    PubMed Central

    2013-01-01

    Background The objective was to investigate the association between BMI and single nucleotide polymorphisms previously identified of obesity-related genes in two Spanish populations. Forty SNPs in 23 obesity-related genes were evaluated in a rural population characterized by a high prevalence of obesity (869 subjects, mean age 46 yr, 62% women, 36% obese) and in an urban population (1425 subjects, mean age 54 yr, 50% women, 19% obese). Genotyping was assessed by using SNPlex and PLINK for the association analysis. Results Polymorphisms of the FTO were significantly associated with BMI, in the rural population (beta 0.87, p-value <0.001). None of the other SNPs showed significant association after Bonferroni correction in the two populations or in the pooled analysis. A weighted genetic risk score (wGRS) was constructed using the risk alleles of the Tag-SNPs with a positive Beta parameter in both populations. From the first to the fifth quintile of the score, the BMI increased 0.45 kg/m2 in Hortega and 2.0 kg/m2 in Pizarra. Overall, the obesity predictive value was low (less than 1%). Conclusion The risk associated with polymorphisms is low and the overall effect on BMI or obesity prediction is minimal. A weighted genetic risk score based on genes mainly acting through central nervous system mechanisms was associated with BMI but it yields minimal clinical prediction for the obesity risk in the general population. PMID:24267414

  17. Sex steroid-related candidate genes in psychiatric disorders.

    PubMed

    Westberg, Lars; Eriksson, Elias

    2008-07-01

    Sex steroids readily pass the blood-brain barrier, and receptors for them are abundant in brain areas important for the regulation of emotions, cognition and behaviour. Animal experiments have revealed both important early effects of these hormones on brain development and their ongoing influence on brain morphology and neurotransmission in the adult organism. The important effects of sex steroids on human behaviour are illustrated by, for example, the effect of reduced levels of these hormones on sexual drive and conditions such as premenstrual dysphoric disorder, perimenopausal dysphoria, postpartum depression, postpartum psychosis, dysphoria induced by oral contraceptives or hormonal replacement therapy and anabolic steroid-induced aggression. The fact that men and women (as groups) differ with respect to the prevalence of several psychiatric disorders, certain aspects of cognitive function and certain personality traits may possibly also reflect an influence of sex steroids on human behaviour. The heritability of most behavioural traits, including personality, cognitive abilities and susceptibility to psychiatric illness, is considerable, but as yet, only few genes of definite importance in this context have been identified. Given the important role of sex steroids for brain function, it is unfortunate that relatively few studies so far have addressed the possible influence of sex steroid-related genes on interindividual differences with respect to personality, cognition and susceptibility to psychiatric disorders. To facilitate further research in this area, this review provides information on several such genes and summarizes what is currently known with respect to their possible influence on brain function.

  18. Purification and properties of hydrogenase from Megasphaera elsdenii.

    PubMed

    Van Dijk, C; Mayhew, S G; Grande, H J; Veeger, C

    1979-12-17

    A hydrogenase has been purified to homogeneity from the soluble fraction of the rumen bacterium Megasphaera elsdenii, the overall purification is 200 times with a yield of 14%. The pure enzyme consists of a single polypeptide chain with Mr approximately 50 000 which contains 12 atoms of non-haem iron and 12 atoms of acid-labile sulphide. The enzyme is rapidly inactivated by O2 and it is therefore purified under nitrogen and in the presence of sodium dithionite. The optical spectrum of the enzyme, after removal of the dithionite with air, shows a peak at 275 nm (epsilon 275 nm = 143 mM-1 cm-1) and a shoulder between 350 nm and 400 nm (epsilon 400 nm = 46 mM-1 cm-1). The enzyme catalyses hydrogen production from sodium dithionite at a low rate. The rate is greatly enhanced by addition of the electron donors flavodoxin, ferredoxin and methyl viologen. The kinetic data with these three electron donors suggest co-operativity, but no indication of self-association of the enzyme was obtained. Sodium chloride enhances the rate of hydrogen production with methyl viologen semiquinone and changes the kinetic behaviour of the enzyme with this electron donor, but causes inhibition of the reactions mediated by ferredoxin and flavodoxin. Two kinetic models were developed which are consistent with the kinetic data of the three electron donors tested. The apparent co-operativity for the hydrogen production can be fitted with the mathematical form of those models. The identical kinetic behaviour of the hydrogenase with the one-electron donors flavodoxin and methyl viologen semiquinone monomer and the two-electron donor ferredoxin indicates that the hydrogenase accepts two electrons in two separate, independent steps and further indicates that the two (4Fe-4S) clusters of the donor ferredoxin are independent. The interpretation of the kinetic data with methyl viologen semiquinone is complicated by the fact that the semiquinone dimerises, and that the formation of the dimer is

  19. Leptin regulates gallbladder genes related to absorption and secretion.

    PubMed

    Swartz-Basile, Deborah A; Lu, Debao; Basile, David P; Graewin, Shannon J; Al-Azzawi, Hayder; Kiely, James M; Mathur, Abhishek; Yancey, Kyle; Pitt, Henry A

    2007-07-01

    Dysregulation of gallbladder ion and water absorption and/or secretion has been linked to cholesterol crystal and gallstone formation. We have recently demonstrated that obese, leptin-deficient (Lep(ob)) mice have enlarged gallbladder volumes and decreased gallbladder contractility and that leptin administration to these mice normalizes gallbladder function. However, the effect of leptin on gallbladder absorption/secretion is not known. Therefore, we sought to determine whether leptin would alter the expression of genes involved in water and ion transport across the gallbladder epithelium. Affymetrix oligonucleotide microarrays representing 39,000 transcripts were used to compare gallbladder gene-expression profiles from 12-wk-old control saline-treated Lep(ob) and from leptin-treated Lep(ob) female mice. Leptin administration to Lep(ob) mice decreased gallbladder volume, bile sodium concentration, and pH. Leptin repletion upregulated the expression of aquaporin 1 water channel by 1.3-fold and downregulated aquaporin 4 by 2.3-fold. A number of genes involved in sodium transport were also influenced by leptin replacement. Epithelial sodium channel-alpha and sodium hydrogen exchangers 1 and 3 were moderately downregulated by 2.0-, 1.6-, and 1.3-fold, respectively. Carbonic anhydrase-IV, which plays a role in the acidification of bile, was upregulated 3.7-fold. In addition, a number of inflammatory cytokines that are known to influence gallbladder epithelial cell absorption and secretion were upregulated. Thus leptin, an adipocyte-derived cytokine involved with satiety and energy balance, influences gallbladder bile volume, sodium, and pH as well as multiple inflammatory cytokine genes and genes related to water, sodium, chloride, and bicarbonate transport.

  20. [Progress on the research of apomixis related genes in plant].

    PubMed

    Hu, Long-Xing

    2008-02-01

    Apomixis is a special asexual reproduction that plants can form embryo and produce progenies via seeds without sperm-egg fusion. Since apomitic embryo is a complete genetic clone of maternal parent without the participation of sperm, it is an ideal pathway to fix and utilize hybrid vigor and has unpredictable potential value in crop breeding, thus be called "the asexual revolution". According to the formation of the apomitic embryos, apomixis could be divided into three major types: diplospory, apospory and adventive embryony. This review is focused on the recent research progresses of related genes in the development of embryo, endosperm, and miosis, and several genes may involved in the regulation of apomitic development.

  1. Genome-wide analysis and identification of genes related to expansin gene family in indica rice.

    PubMed

    Hemalatha, N; Rajesh, M K; Narayanan, N K

    2011-01-01

    In this study, we carried out genome-wide analyses to explore expansin gene family in the genome of indica rice. Reference nucleotides were chosen as query sequences for searches in the indica rice genome database. Clones having genomic sequences similar to expansin were taken and converted to amino acid sequences. Putative sequences were subjected to PROSITE and Pfam databases, and 21 signature-sequences-related expansin gene family was obtained. The presence of transmembrane domains was also predicted for all 21 expansin proteins. A phylogenetic tree was generated from the alignments of the proteins sequences to examine the phylogenetic relationship of indica rice expansin proteins.

  2. Functional model for the [Fe] hydrogenase inspired by the frustrated Lewis pair concept.

    PubMed

    Kalz, Kai F; Brinkmeier, Alexander; Dechert, Sebastian; Mata, Ricardo A; Meyer, Franc

    2014-11-26

    [Fe] hydrogenase (Hmd) catalyzes the heterolytic splitting of H2 by using, in its active site, a unique organometallic iron-guanylylpyridinol (FeGP) cofactor and, as a hydride acceptor, the substrate methenyltetrahydromethanopterin (methenyl-H4MPT(+)). The combination FeGP/methenyl-H4MPT(+) and its reactivity bear resemblance to the concept of frustrated Lewis pairs (FLPs), some of which have been shown to heterolytically activate H2. The present work exploits this interpretation of Hmd reactivity by using the combination of Lewis basic ruthenium metalates, namely K[CpRu(CO)2] (KRp) and a related polymeric Cp/Ru/CO compound (Rs), with the new imidazolinium salt 1,3-bis(2,6-difluorophenyl)-2-(4-tolyl)imidazolinium bromide ([(Tol)Im(F4)](+)Br(-)) that was designed to emulate the hydride acceptor properties of methenyl-H4MPT(+). Solid-state structures of [(Tol)Im(F4)](+)Br(-) and the corresponding imidazolidine H(Tol)Im(F4) reveal that the heterocycle undergoes similar structural changes as in the biological substrate. DFT calculations indicate that heterolytic splitting of dihydrogen by the FLP Rp(-)/[(Tol)Im(F4)](+) is exothermic, but the formation of the initial Lewis pair should be unfavorable in polar solvents. Consequently the combination Rp(-)/[(Tol)Im(F4)](+) does not react with H2 but leads instead to side products from nucleophilic substitution (k = 4 × 10(-2) L mol (-1) s(-1) at room temperature). In contrast, the heterogeneous combination Rs/[(Tol)Im(F4)](+) does split H2 heterolytically to give H(Tol)Im(F4) and HRuCp(CO)2 (HRp) or D(Tol)Im(F4) and DRp when using D2. The reaction has been followed by (1)H/(2)H and (19)F NMR spectroscopy as well as by IR spectroscopy and reaches 96% conversion after 1 d. Formation of H(Tol)Im(F4) under these conditions demonstrates that superelectrophilic activation by protonation, which has been proposed for methenyl-H4MPT(+) to increase its carbocationic character, is not necessarily required for an imidazolinium ion to

  3. Formaldehyde--a rapid and reversible inhibitor of hydrogen production by [FeFe]-hydrogenases.

    PubMed

    Wait, Annemarie F; Brandmayr, Caterina; Stripp, Sven T; Cavazza, Christine; Fontecilla-Camps, Juan C; Happe, Thomas; Armstrong, Fraser A

    2011-02-01

    Dihydrogen (H(2)) production by [FeFe]-hydrogenases is strongly inhibited by formaldehyde (methanal) in a reaction that is rapid, reversible, and specific to this type of hydrogenase. This discovery, using three [FeFe]-hydrogenases that are homologous about the active site but otherwise structurally distinct, was made by protein film electrochemistry, which measures the activity (as electrical current) of enzymes immobilized on an electrode; importantly, the inhibitor can be removed after addition. Formaldehyde causes rapid loss of proton reduction activity which is restored when the solution is exchanged. Inhibition is confirmed by conventional solution assays. The effect depends strongly on the direction of catalysis: inhibition of H(2) oxidation is much weaker than for H(2) production, and formaldehyde also protects against CO and O(2) inactivation. By contrast, inhibition of [NiFe]-hydrogenases is weak. The results strongly suggest that formaldehyde binds at, or close to, the active site of [FeFe]-hydrogenases at a site unique to this class of enzyme--highly conserved lysine and cysteine residues, the bridgehead atom of the dithiolate ligand, or the reduced Fe(d) that is the focal center of catalysis.

  4. Formaldehyde--a rapid and reversible inhibitor of hydrogen production by [FeFe]-hydrogenases.

    PubMed

    Wait, Annemarie F; Brandmayr, Caterina; Stripp, Sven T; Cavazza, Christine; Fontecilla-Camps, Juan C; Happe, Thomas; Armstrong, Fraser A

    2011-02-01

    Dihydrogen (H(2)) production by [FeFe]-hydrogenases is strongly inhibited by formaldehyde (methanal) in a reaction that is rapid, reversible, and specific to this type of hydrogenase. This discovery, using three [FeFe]-hydrogenases that are homologous about the active site but otherwise structurally distinct, was made by protein film electrochemistry, which measures the activity (as electrical current) of enzymes immobilized on an electrode; importantly, the inhibitor can be removed after addition. Formaldehyde causes rapid loss of proton reduction activity which is restored when the solution is exchanged. Inhibition is confirmed by conventional solution assays. The effect depends strongly on the direction of catalysis: inhibition of H(2) oxidation is much weaker than for H(2) production, and formaldehyde also protects against CO and O(2) inactivation. By contrast, inhibition of [NiFe]-hydrogenases is weak. The results strongly suggest that formaldehyde binds at, or close to, the active site of [FeFe]-hydrogenases at a site unique to this class of enzyme--highly conserved lysine and cysteine residues, the bridgehead atom of the dithiolate ligand, or the reduced Fe(d) that is the focal center of catalysis. PMID:21204519

  5. (Catalytic mechanism of hydrogenase from aerobic N sub 2 -fixing microorganisms)

    SciTech Connect

    Arp, D.J.

    1990-01-01

    Hydrogenases are enzymes which catalyze reactions involving dihydrogen. They serve integral roles in a number of microbial metabolic pathways. Our research is focussed on investigations of the catalytic mechanism of the hydrogenases found in aerobic, N{sub 2}-fixing microorganisms such as Azotobacter vinelandii and the agronomically important Bradyrhizobium japonicum as well as microorganisms with similar hydrogenases. The hydrogenases isolated from these microorganisms are Ni- and Fe-containing heterodimers. Our work has focussed on three areas during the last grant period. In all cases, a central theme has been the role of inhibitors in the characteristics under investigation. In addition, a number of collaborative efforts have yielded interesting results. In metalloenzymes such as hydrogenase, inhibitors often influence the activity of the enzyme through ligand interactions with redox centers, often metals, within the enzyme. Therefore, investigations of the ability of various compounds to inhibit an enzyme's activity, as well as the mechanism of inhibition, can provide insight into the catalytic mechanism of the enzyme as well as the role of various redox centers in catalysis. We have investigated in detail four inhibitors of A. vinelandii and the results are summarized here. The influence of these inhibitors on the spectral properties of the enzyme are summarized. Electron paramagnetic resonance and ultraviolet spectra investigations are discussed. 9 figs.

  6. Three different [NiFe] hydrogenases confer metabolic flexibility in the obligate aerobe Mycobacterium smegmatis.

    PubMed

    Berney, Michael; Greening, Chris; Hards, Kiel; Collins, Desmond; Cook, Gregory M

    2014-01-01

    Mycobacterium smegmatis is an obligate aerobe that harbours three predicted [NiFe] hydrogenases, Hyd1 (MSMEG_2262–2263), Hyd2 (MSMEG_2720-2719) and Hyd3 (MSMEG_3931-3928). We show here that these three enzymes differ in their phylogeny, regulation and catalytic activity. Phylogenetic analysis revealed that Hyd1 groups with hydrogenases that oxidize H2 produced by metabolic processes, and Hyd2 is homologous to a novel group of putative high-affinity hydrogenases. Hyd1 and Hyd2 respond to carbon and oxygen limitation, and, in the case of Hyd1, hydrogen supplementation. Hydrogen consumption measurements confirmed that both enzymes can oxidize hydrogen. In contrast, the phylogenetic analysis and activity measurements of Hyd3 are consistent with the enzyme evolving hydrogen. Hyd3 is controlled by DosR, a regulator that responds to hypoxic conditions. The strict dependence of hydrogen oxidation of Hyd1 and Hyd2 on oxygen suggests that the enzymes are oxygen tolerant and linked to the respiratory chain. This unique combination of hydrogenases allows M. smegmatis to oxidize hydrogen at high (Hyd1) and potentially tropospheric (Hyd2) concentrations, as well as recycle reduced equivalents by evolving hydrogen (Hyd3). The distribution of these hydrogenases throughout numerous soil and marine species of actinomycetes suggests that oxic hydrogen metabolism provides metabolic flexibility in environments with changing nutrient fluxes.

  7. A gene and protein expression study on four porcine genes related to intramuscular fat deposition.

    PubMed

    Zappaterra, Martina; Deserti, Marzia; Mazza, Roberta; Braglia, Silvia; Zambonelli, Paolo; Davoli, Roberta

    2016-11-01

    Intramuscular fat (IMF) content has a prominent role in meat quality, affecting sensory attributes such as flavour and texture. In the present research, we studied in samples of porcine Semimembranosus muscle four genes related to lipid metabolism and whose gene expressions have been associated to IMF deposition: FASN, SCD, LIPE and LPL. We analysed both mRNA and protein expressions in two groups of Italian Large White pigs divergent for Semimembranosus IMF deposition, with the aim of comparing the levels of four genes and enzymes between the two groups and identifying possible coexpression links. The obtained results suggest a prominent role of LIPE enzyme in IMF hydrolysis, as the samples with low IMF deposition show a significantly higher amount of this lipase. Finally, a poorly known correlation was found between LIPE and FASN enzymes only in female individuals. These results provide new information for the understanding of IMF deposition. PMID:27236338

  8. Characterization of the oxygen tolerance of a hydrogenase linked to a carbon monoxide oxidation pathway in Rubrivivax gelatinosus.

    PubMed

    Maness, Pin-Ching; Smolinski, Sharon; Dillon, Anne C; Heben, Michael J; Weaver, Paul F

    2002-06-01

    A hydrogenase linked to the carbon monoxide oxidation pathway in Rubrivivax gelatinosus displays tolerance to O2. When either whole-cell or membrane-free partially purified hydrogenase was stirred in full air (21% O2, 79% N2), its H2 evolution activity exhibited a half-life of 20 or 6 h, respectively, as determined by an anaerobic assay using reduced methyl viologen. When the partially purified hydrogenase was stirred in an atmosphere containing either 3.3 or 13% O2 for 15 min and evaluated by a hydrogen-deuterium (H-D) exchange assay, nearly 80 or 60% of its isotopic exchange rate was retained, respectively. When this enzyme suspension was subsequently returned to an anaerobic atmosphere, more than 90% of the H-D exchange activity was recovered, reflecting the reversibility of this hydrogenase toward O2 inactivation. Like most hydrogenases, the CO-linked hydrogenase was extremely sensitive to CO, with 50% inhibition occurring at 3.9 microM dissolved CO. Hydrogen production from the CO-linked hydrogenase was detected when ferredoxins of a prokaryotic source were the immediate electron mediator, provided they were photoreduced by spinach thylakoid membranes containing active water-splitting activity. Based on its appreciable tolerance to O2, potential applications of this hydrogenase are discussed.

  9. Characterization of the Oxygen Tolerance of a Hydrogenase Linked to a Carbon Monoxide Oxidation Pathway in Rubrivivax gelatinosus

    PubMed Central

    Maness, Pin-Ching; Smolinski, Sharon; Dillon, Anne C.; Heben, Michael J.; Weaver, Paul F.

    2002-01-01

    A hydrogenase linked to the carbon monoxide oxidation pathway in Rubrivivax gelatinosus displays tolerance to O2. When either whole-cell or membrane-free partially purified hydrogenase was stirred in full air (21% O2, 79% N2), its H2 evolution activity exhibited a half-life of 20 or 6 h, respectively, as determined by an anaerobic assay using reduced methyl viologen. When the partially purified hydrogenase was stirred in an atmosphere containing either 3.3 or 13% O2 for 15 min and evaluated by a hydrogen-deuterium (H-D) exchange assay, nearly 80 or 60% of its isotopic exchange rate was retained, respectively. When this enzyme suspension was subsequently returned to an anaerobic atmosphere, more than 90% of the H-D exchange activity was recovered, reflecting the reversibility of this hydrogenase toward O2 inactivation. Like most hydrogenases, the CO-linked hydrogenase was extremely sensitive to CO, with 50% inhibition occurring at 3.9 μM dissolved CO. Hydrogen production from the CO-linked hydrogenase was detected when ferredoxins of a prokaryotic source were the immediate electron mediator, provided they were photoreduced by spinach thylakoid membranes containing active water-splitting activity. Based on its appreciable tolerance to O2, potential applications of this hydrogenase are discussed. PMID:12039713

  10. [NiFe]-hydrogenase is essential for cyanobacterium Synechocystis sp. PCC 6803 aerobic growth in the dark

    PubMed Central

    De Rosa, Edith; Checchetto, Vanessa; Franchin, Cinzia; Bergantino, Elisabetta; Berto, Paola; Szabò, Ildikò; Giacometti, Giorgio M.; Arrigoni, Giorgio; Costantini, Paola

    2015-01-01

    The cyanobacterium Synechocystis sp. PCC 6803 has a bidirectional [NiFe]-hydrogenase (Hox hydrogenase) which reversibly reduces protons to H2. This enzyme is composed of a hydrogenase domain and a diaphorase moiety, which is distinctly homologous to the NADH input module of mitochondrial respiratory Complex I. Hox hydrogenase physiological function is still unclear, since it is not required for Synechocystis fitness under standard growth conditions. We analyzed the phenotype under prolonged darkness of three Synechocystis knock-out strains, lacking either Hox hydrogenase (ΔHoxE-H) or one of the proteins responsible for the assembly of its NiFe active site (ΔHypA1 and ΔHypB1). We found that Hox hydrogenase is required for Synechocystis growth under this condition, regardless of the functional status of its catalytic site, suggesting an additional role beside hydrogen metabolism. Moreover, quantitative proteomic analyses revealed that the expression levels of several subunits of the respiratory NADPH/plastoquinone oxidoreductase (NDH-1) are reduced when Synechocystis is grown in the dark. Our findings suggest that the Hox hydrogenase could contribute to electron transport regulation when both photosynthetic and respiratory pathways are down-regulated, and provide a possible explanation for the close evolutionary relationship between mitochondrial respiratory Complex I and cyanobacterial [NiFe]-hydrogenases. PMID:26215212

  11. A modular system for regeneration of NAD cofactors using graphite particles modified with hydrogenase and diaphorase moieties.

    PubMed

    Reeve, Holly A; Lauterbach, Lars; Ash, Philip A; Lenz, Oliver; Vincent, Kylie A

    2012-02-01

    Pyrolytic graphite particles modified with hydrogenase and an NAD(+)/NADH cycling enzyme provide a modular heterogeneous catalyst system for regeneration of oxidised or reduced nicotinamide cofactors using H(2) and H(+) as electron source or sink. Particles can be tuned for cofactor supply under different conditions by appropriate choice of hydrogenase. PMID:21986817

  12. Tenm, a Drosophila gene related to tenascin, is a new pair-rule gene.

    PubMed Central

    Baumgartner, S; Martin, D; Hagios, C; Chiquet-Ehrismann, R

    1994-01-01

    We describe the molecular characterization of the Drosophila gene tenm, a large transcription unit spanning > 110 kb of DNA. tenm encodes a large extracellular protein of 2515 amino acids related to the extracellular matrix molecule tenascin. The Tenm protein is found in seven stripes during the blastoderm stage, and each stripe overlaps with the even-skipped stripes. tenm mutants show a phenotype resembling that of odd-paired (opa), a member of the pair-rule class of segmentation genes. Thus, Tenm is the first example of a pair-rule gene product acting from outside the cell. While the Tenm protein is under the control of fushi tarazu and even-skipped, but not of opa, at least two pair-rule genes, paired (prd) and sloppy paired (slp), and all segment-polarity genes analysed to date are under the control of tenm. Our data suggest that Tenm initiates a signal transduction cascade which acts, via or in concert with opa, on downstream targets such as prd, slp, gooseberry, engrailed and wingless, leading to an opa-like phenotype. Images PMID:8070401

  13. Intact Functional Fourteen-subunit Respiratory Membrane-bound [NiFe]-Hydrogenase Complex of the Hyperthermophilic Archaeon Pyrococcus furiosus*

    PubMed Central

    McTernan, Patrick M.; Chandrayan, Sanjeev K.; Wu, Chang-Hao; Vaccaro, Brian J.; Lancaster, W. Andrew; Yang, Qingyuan; Fu, Dax; Hura, Greg L.; Tainer, John A.; Adams, Michael W. W.

    2014-01-01

    The archaeon Pyrococcus furiosus grows optimally at 100 °C by converting carbohydrates to acetate, CO2, and H2, obtaining energy from a respiratory membrane-bound hydrogenase (MBH). This conserves energy by coupling H2 production to oxidation of reduced ferredoxin with generation of a sodium ion gradient. MBH is encoded by a 14-gene operon with both hydrogenase and Na+/H+ antiporter modules. Herein a His-tagged MBH was expressed in P. furiosus and the detergent-solubilized complex purified under anaerobic conditions by affinity chromatography. Purified MBH contains all 14 subunits by electrophoretic analysis (13 subunits were also identified by mass spectrometry) and had a measured iron:nickel ratio of 15:1, resembling the predicted value of 13:1. The as-purified enzyme exhibited a rhombic EPR signal characteristic of the ready nickel-boron state. The purified and membrane-bound forms of MBH both preferentially evolved H2 with the physiological donor (reduced ferredoxin) as well as with standard dyes. The O2 sensitivities of the two forms were similar (half-lives of ∼15 h in air), but the purified enzyme was more thermolabile (half-lives at 90 °C of 1 and 25 h, respectively). Structural analysis of purified MBH by small angle x-ray scattering indicated a Z-shaped structure with a mass of 310 kDa, resembling the predicted value (298 kDa). The angle x-ray scattering analyses reinforce and extend the conserved sequence relationships of group 4 enzymes and complex I (NADH quinone oxidoreductase). This is the first report on the properties of a solubilized form of an intact respiratory MBH complex that is proposed to evolve H2 and pump Na+ ions. PMID:24860091

  14. Intact functional fourteen-subunit respiratory membrane-bound [NiFe]-hydrogenase complex of the hyperthermophilic archaeon Pyrococcus furiosus.

    PubMed

    McTernan, Patrick M; Chandrayan, Sanjeev K; Wu, Chang-Hao; Vaccaro, Brian J; Lancaster, W Andrew; Yang, Qingyuan; Fu, Dax; Hura, Greg L; Tainer, John A; Adams, Michael W W

    2014-07-11

    The archaeon Pyrococcus furiosus grows optimally at 100 °C by converting carbohydrates to acetate, CO2, and H2, obtaining energy from a respiratory membrane-bound hydrogenase (MBH). This conserves energy by coupling H2 production to oxidation of reduced ferredoxin with generation of a sodium ion gradient. MBH is encoded by a 14-gene operon with both hydrogenase and Na(+)/H(+) antiporter modules. Herein a His-tagged MBH was expressed in P. furiosus and the detergent-solubilized complex purified under anaerobic conditions by affinity chromatography. Purified MBH contains all 14 subunits by electrophoretic analysis (13 subunits were also identified by mass spectrometry) and had a measured iron:nickel ratio of 15:1, resembling the predicted value of 13:1. The as-purified enzyme exhibited a rhombic EPR signal characteristic of the ready nickel-boron state. The purified and membrane-bound forms of MBH both preferentially evolved H2 with the physiological donor (reduced ferredoxin) as well as with standard dyes. The O2 sensitivities of the two forms were similar (half-lives of ∼ 15 h in air), but the purified enzyme was more thermolabile (half-lives at 90 °C of 1 and 25 h, respectively). Structural analysis of purified MBH by small angle x-ray scattering indicated a Z-shaped structure with a mass of 310 kDa, resembling the predicted value (298 kDa). The angle x-ray scattering analyses reinforce and extend the conserved sequence relationships of group 4 enzymes and complex I (NADH quinone oxidoreductase). This is the first report on the properties of a solubilized form of an intact respiratory MBH complex that is proposed to evolve H2 and pump Na(+) ions. PMID:24860091

  15. Brownian Dynamics and Molecular Dynamics Study of the Association Between Hydrogenase and Ferredoxin from the Chlamydomonas reinhardtii

    SciTech Connect

    Long, H.; Chang, C. H.; King, P. W.; Ghirardi, M. L.; Kim, K.

    2008-10-01

    The [FeFe] hydrogenase from the green alga Chlamydomonas reinhardtii can catalyze the reduction of protons to hydrogen gas using electrons supplied from photosystem I and transferred via ferredoxin. To better understand the association of the hydrogenase and the ferredoxin, we have simulated the process over multiple timescales. A Brownian dynamics simulation method gave an initial thorough sampling of the rigid-body translational and rotational phase spaces, and the resulting trajectories were used to compute the occupancy and free-energy landscapes. Several important hydrogenase-ferredoxin encounter complexes were identified from this analysis, which were then individually simulated using atomistic molecular dynamics to provide more details of the hydrogenase and ferredoxin interaction. The ferredoxin appeared to form reasonable complexes with the hydrogenase in multiple orientations, some of which were good candidates for inclusion in a transition state ensemble of configurations for electron transfer.

  16. Functional Analysis by Site-Directed Mutagenesis of the NAD+-Reducing Hydrogenase from Ralstonia eutropha

    PubMed Central

    Burgdorf, Tanja; De Lacey, Antonio L.; Friedrich, Bärbel

    2002-01-01

    The tetrameric cytoplasmic [NiFe] hydrogenase (SH) of Ralstonia eutropha couples the oxidation of hydrogen to the reduction of NAD+ under aerobic conditions. In the catalytic subunit HoxH, all six conserved motifs surrounding the [NiFe] site are present. Five of these motifs were altered by site-directed mutagenesis in order to dissect the molecular mechanism of hydrogen activation. Based on phenotypic characterizations, 27 mutants were grouped into four different classes. Mutants of the major class, class I, failed to grow on hydrogen and were devoid of H2-oxidizing activity. In one of these isolates (HoxH I64A), H2 binding was impaired. Class II mutants revealed a high D2/H+ exchange rate relative to a low H2-oxidizing activity. A representative (HoxH H16L) displayed D2/H+ exchange but had lost electron acceptor-reducing activity. Both activities were equally affected in class III mutants. Mutants forming class IV showed a particularly interesting phenotype. They displayed O2-sensitive growth on hydrogen due to an O2-sensitive SH protein. PMID:12399498

  17. Identification of Genes to Differentiate Closely Related Salmonella Lineages

    PubMed Central

    Zou, Qing-Hua; Li, Ren-Qing; Wang, Ye-Jun; Liu, Shu-Lin

    2013-01-01

    Background Salmonella are important human and animal pathogens. Though highly related, the Salmonella lineages may be strictly adapted to different hosts or cause different diseases, from mild local illness like gastroenteritis to fatal systemic infections like typhoid. Therefore, rapid and accurate identification of Salmonella is essential for timely and correct diagnosis of Salmonella infections. The current identification methods such as 16S rRNA sequencing and multilocus sequence typing are expensive and time consuming. Additionally, these methods often do not have sufficient distinguishing resolution among the Salmonella lineages. Methodologies/Principal Findings We compared 27 completely sequenced Salmonella genomes to identify possible genomic features that could be used for differentiation of individual lineages. We concatenated 2372 core genes in each of the 27 genomes and constructed a neighbor-joining tree. On the tree, strains of each serotype were clustered tightly together and different serotypes were unambiguously separated with clear genetic distances, demonstrating systematic genomic divergence among the Salmonella lineages. We made detailed comparisons among the 27 genomes and identified distinct sets of genomic differences, including nucleotide variations and genomic islands (GIs), among the Salmonella lineages. Two core genes STM4261 and entF together could unambiguously distinguish all Salmonella lineages compared in this study. Additionally, strains of a lineage have a common set of GIs and closely related lineages have similar sets of GIs. Conclusions Salmonella lineages have accumulated distinct sets of mutations and laterally acquired DNA (e.g., GIs) in evolution. Two genes entF and STM4261 have diverged sufficiently among the Salmonella lineages to be used for their differentiation. Further investigation of the distinct sets of mutations and GIs will lead to novel insights into genomic evolution of Salmonella and greatly facilitate the

  18. Transport of Magnesium by a Bacterial Nramp-Related Gene

    PubMed Central

    Rodionov, Dmitry A.; Freedman, Benjamin G.; Senger, Ryan S.; Winkler, Wade C.

    2014-01-01

    Magnesium is an essential divalent metal that serves many cellular functions. While most divalent cations are maintained at relatively low intracellular concentrations, magnesium is maintained at a higher level (∼0.5–2.0 mM). Three families of transport proteins were previously identified for magnesium import: CorA, MgtE, and MgtA/MgtB P-type ATPases. In the current study, we find that expression of a bacterial protein unrelated to these transporters can fully restore growth to a bacterial mutant that lacks known magnesium transporters, suggesting it is a new importer for magnesium. We demonstrate that this transport activity is likely to be specific rather than resulting from substrate promiscuity because the proteins are incapable of manganese import. This magnesium transport protein is distantly related to the Nramp family of proteins, which have been shown to transport divalent cations but have never been shown to recognize magnesium. We also find gene expression of the new magnesium transporter to be controlled by a magnesium-sensing riboswitch. Importantly, we find additional examples of riboswitch-regulated homologues, suggesting that they are a frequent occurrence in bacteria. Therefore, our aggregate data discover a new and perhaps broadly important path for magnesium import and highlight how identification of riboswitch RNAs can help shed light on new, and sometimes unexpected, functions of their downstream genes. PMID:24968120

  19. Mechanism of inhibition of NiFe hydrogenase by nitric oxide.

    PubMed

    Ceccaldi, Pierre; Etienne, Emilien; Dementin, Sébastien; Guigliarelli, Bruno; Léger, Christophe; Burlat, Bénédicte

    2016-04-01

    Hydrogenases reversibly catalyze the oxidation of molecular hydrogen and are inhibited by several small molecules including O2, CO and NO. In the present work, we investigate the mechanism of inhibition by NO of the oxygen-sensitive NiFe hydrogenase from Desulfovibrio fructosovorans by coupling site-directed mutagenesis, protein film voltammetry (PFV) and EPR spectroscopy. We show that micromolar NO strongly inhibits NiFe hydrogenase and that the mechanism of inhibition is complex, with NO targeting several metallic sites in the protein. NO reacts readily at the NiFe active site according to a two-step mechanism. The first and faster step is the reversible binding of NO to the active site followed by a slower and irreversible transformation at the active site. NO also induces irreversible damage of the iron-sulfur centers chain. We give direct evidence of preferential nitrosylation of the medial [3Fe-4S] to form dinitrosyl-iron complexes. PMID:26827939

  20. Immobilization of isolated and cellular hydrogenase of D. desulfuricans in radiation-polymerized polyacrylamides

    SciTech Connect

    Ziomek, E.; Martin, W.G.; Williams, R.E.

    1984-02-01

    Purified hydrogenase from Desulfovibrio desulfuricans was immobilized either by entrapment or absorption onto porous neutral and charged acrylamide beads. Surface absorption and crosslinking on the beads resulted in a high hydrogenase activity and a good immobilization coefficient compared to the enzyme and whole cells entrapped in the same matrix. Maximum enzyme activity (citrate-phosphate buffer) was shifted to pH 6.5 upon immobilization in contrast to 6.0 for the free enzyme and the range of 6-7 for whole cells. Both the purified enzyme and whole cells were most active when held in neutral matrices. Immobilization improved the temperature stability (65 degrees C) and long term storage (4 degrees C) of the hydrogenase activity of both the purified enzyme and whole cells.

  1. Immobilization of isolated and cellular hydrogenase of D. desulfuricans in radiation-polymerized polyacrylamides.

    PubMed

    Ziomek, E; Martin, W G; Williams, R E

    1984-02-01

    Purified hydrogenase from Desulfovibrio desulfuricans was immobilized either by entrapment or absorption onto porous neutral and charged acrylamide beads. Surface absorption and crosslinking on the beads resulted in a high hydrogenase activity and a good immobilization coefficient compared to the enzyme and whole cells entrapped in the same matrix. Maximum enzyme activity (citrate-phosphate buffer) was shifted to pH 6.5 upon immobilization in contrast to 6.0 for the free enzyme and the range of 6-7 for whole cells. Both the purified enzyme and whole cells were most active when held in neutral matrices. Immobilization improved the temperature stability (65 degrees C) and long term storage (4 degrees C) of the hydrogenase activity of both the purified enzyme and whole cells. PMID:6383215

  2. Immobilized chloroplast-ferredoxin-hydrogenase system for the simultaneous photoproduction of hydrogen and oxygen

    SciTech Connect

    Woodward, J.; Greenbaum, E.

    1983-01-01

    The chloroplast-ferredoxin-hydrogenase (CFH) system is capable of the simultaneous photoproduction of hydrogen and oxygen using water as the source of electrons. The immobilization of chloroplasts and hydrogenase, which has been the subject of several reports, has been attempted in order to increase their storage and functional stability. However, immobilized chloroplasts and hydrogenase have never been shown to produce hydrogen and oxygen simultaneously. The simultaneous photoproduction of hydrogen and oxygen is a valuable guide in assessing the role of water as the primary substrate in biophotolysis. As has been shown previously, the stoichiometric ratio of hydrogen to oxygen is, in general, not equal to two. By measuring the oxygen that is produced along with the hydrogen, it is possible to set an upper limit on the photoproduced hydrogen that is derived from water. The study reported here describes for the first time the simultaneous photoproduction of hydrogen and oxygen by the CFH system immobilized in calcium alginate gel spheres.

  3. Gene Therapy for Age-Related Macular Degeneration.

    PubMed

    Constable, Ian Jeffery; Blumenkranz, Mark Scott; Schwartz, Steven D; Barone, Sam; Lai, Chooi-May; Rakoczy, Elizabeth Piroska

    2016-01-01

    The purpose of this article was to evaluate safety and signals of efficacy of gene therapy with subretinal rAAV.sFlt-1 for wet age-related macular degeneration (wet AMD). A phase 1 dose-escalating single-center controlled unmasked human clinical trial was followed up by extension of the protocol to a phase 2A single-center trial. rAAV.sFlt-1 vector was used to deliver a naturally occurring anti-vascular endothelial growth factor agent, sFlt-1, into the subretinal space. In phase 1, step 1 randomized 3 subjects to low-dose rAAV.sFlt-1 (1 × 10 vector genomes) and 1 subject to the control arm; step 2 randomized an additional 3 subjects to treatment with high-dose rAAV.sFlt-1 (1 × 10 vector genomes) and 1 subject to the control arm. Follow-up studies demonstrated that rAAV.sFlt-1 was well tolerated with a favorable safety profile in these elderly subjects with wet AMD. Subretinal injection was highly reproducible, and no drug-related adverse events were reported. Procedure-related adverse events were mild and self-resolving. Two phakic patients developed cataract and underwent cataract surgery. Four of the 6 patients responded better than the small control group in this study and historical controls in terms of maintaining vision and a relatively dry retina with zero ranibizumab retreatments per annum. Two patients required 1 ranibizumab injection over the 52-week follow-up period. rAAV.sFlt-1 gene therapy may prove to be a potential adjunct or alternative to conventional intravitreal injection for patients with wet AMD by providing extended delivery of a naturally occurring antiangiogenic protein. PMID:27488071

  4. [FeFe]- and [NiFe]-hydrogenase diversity, mechanism, and maturation.

    PubMed

    Peters, John W; Schut, Gerrit J; Boyd, Eric S; Mulder, David W; Shepard, Eric M; Broderick, Joan B; King, Paul W; Adams, Michael W W

    2015-06-01

    The [FeFe]- and [NiFe]-hydrogenases catalyze the formal interconversion between hydrogen and protons and electrons, possess characteristic non-protein ligands at their catalytic sites and thus share common mechanistic features. Despite the similarities between these two types of hydrogenases, they clearly have distinct evolutionary origins and likely emerged from different selective pressures. [FeFe]-hydrogenases are widely distributed in fermentative anaerobic microorganisms and likely evolved under selective pressure to couple hydrogen production to the recycling of electron carriers that accumulate during anaerobic metabolism. In contrast, many [NiFe]-hydrogenases catalyze hydrogen oxidation as part of energy metabolism and were likely key enzymes in early life and arguably represent the predecessors of modern respiratory metabolism. Although the reversible combination of protons and electrons to generate hydrogen gas is the simplest of chemical reactions, the [FeFe]- and [NiFe]-hydrogenases have distinct mechanisms and differ in the fundamental chemistry associated with proton transfer and control of electron flow that also help to define catalytic bias. A unifying feature of these enzymes is that hydrogen activation itself has been restricted to one solution involving diatomic ligands (carbon monoxide and cyanide) bound to an Fe ion. On the other hand, and quite remarkably, the biosynthetic mechanisms to produce these ligands are exclusive to each type of enzyme. Furthermore, these mechanisms represent two independent solutions to the formation of complex bioinorganic active sites for catalyzing the simplest of chemical reactions, reversible hydrogen oxidation. As such, the [FeFe]- and [NiFe]-hydrogenases are arguably the most profound case of convergent evolution. This article is part of a Special Issue entitled: Fe/S proteins: Analysis, structure, function, biogenesis and diseases. PMID:25461840

  5. Production and purification of a soluble hydrogenase from Ralstonia eutropha H16 for potential hydrogen fuel cell applications.

    PubMed

    Jugder, Bat-Erdene; Lebhar, Helene; Aguey-Zinsou, Kondo-Francois; Marquis, Christopher P

    2016-01-01

    The soluble hydrogenase (SH) from Ralstonia eutropha H16 is a promising candidate enzyme for H2-based biofuel application as it favours H2 oxidation and is relatively oxygen-tolerant. In this report, bioprocess development studies undertaken to produce and purify an active SH are described, based on the methods previously reported [1], [2], [3], [4]. Our modifications are: •Upstream method optimizations were undertaken on heterotrophic growth media and cell lysis involving ultrasonication.•Two anion exchangers (Q Sepharose and RESOURCE Q) and size exclusion chromatographic (Superdex 200) matrices were successfully employed for purification of a hexameric SH from R. eutropha.•The H2 oxidizing activity of the SH was demonstrated spectrophotometrically in solution and also immobilized on an EPG electrode using cyclic voltammetry. PMID:27077052

  6. Hydrogen Production by a Hyperthermophilic Membrane-Bound Hydrogenase in Soluble Nanolipoprotein Particles

    SciTech Connect

    Baker, S E; Hopkins, R C; Blanchette, C; Walsworth, V; Sumbad, R; Fischer, N; Kuhn, E; Coleman, M; Chromy, B; Letant, S; Hoeprich, P; Adams, M W; Henderson, P T

    2008-10-22

    Hydrogenases constitute a promising class of enzymes for ex vivo hydrogen production. Implementation of such applications is currently hindered by oxygen sensitivity and, in the case of membrane-bound hydrogenases (MBH), poor water solubility. Nanolipoprotein particles (NLPs), formed from apolipoproteins and phospholipids, offer a novel means to incorporate MBH into in a well-defined water-soluble matrix that maintains the enzymatic activity and is amenable to incorporation into more complex architectures. We report the synthesis, hydrogen-evolving activity and physical characterization of the first MBH-NLP assembly. This may ultimately lead to the development of biomimetic hydrogen production devices.

  7. Concerto catalysis--harmonising [NiFe]hydrogenase and NiRu model catalysts.

    PubMed

    Ichikawa, Koji; Nonaka, Kyoshiro; Matsumoto, Takahiro; Kure, Bunsho; Yoon, Ki-Seok; Higuchi, Yoshiki; Yagi, Tatsuhiko; Ogo, Seiji

    2010-03-28

    This communication reports the successful merging of the chemical properties of a natural [NiFe]hydrogenase (Desulfovibrio vulgaris Miyazaki F) and our previously reported [NiRu] hydrogenase-mimic. The catalytic activity of both the natural enzyme and the mimic is almost identical, with the exception of working pH ranges, and this allows us to use them simultaneously in the same reaction flask. In such a manner, isotope exchange between D(2) and H(2)O could be conducted over an extended pH range (about 2-10) in one pot under mild conditions at ambient temperature and pressure.

  8. Phenotype-based clustering of glycosylation-related genes by RNAi-mediated gene silencing.

    PubMed

    Yamamoto-Hino, Miki; Yoshida, Hideki; Ichimiya, Tomomi; Sakamura, Sho; Maeda, Megumi; Kimura, Yoshinobu; Sasaki, Norihiko; Aoki-Kinoshita, Kiyoko F; Kinoshita-Toyoda, Akiko; Toyoda, Hidenao; Ueda, Ryu; Nishihara, Shoko; Goto, Satoshi

    2015-06-01

    Glycan structures are synthesized by a series of reactions conducted by glycosylation-related (GR) proteins such as glycosyltransferases, glycan-modifying enzymes, and nucleotide-sugar transporters. For example, the common core region of glycosaminoglycans (GAGs) is sequentially synthesized by peptide-O-xylosyltransferase, β1,4-galactosyltransferase I, β1,3-galactosyltransferase II, and β1,3-glucuronyltransferase. This raises the possibility that functional impairment of GR proteins involved in synthesis of the same glycan might result in the same phenotypic abnormality. To examine this possibility, comprehensive silencing of genes encoding GR and proteoglycan core proteins was conducted in Drosophila. Drosophila GR candidate genes (125) were classified into five functional groups for synthesis of GAGs, N-linked, O-linked, Notch-related, and unknown glycans. Spatiotemporally regulated silencing caused a range of malformed phenotypes that fell into three types: extra veins, thick veins, and depigmentation. The clustered phenotypes reflected the biosynthetic pathways of GAGs, Fringe-dependent glycan on Notch, and glycans placed at or near nonreducing ends (herein termed terminal domains of glycans). Based on the phenotypic clustering, CG33145 was predicted to be involved in formation of terminal domains. Our further analysis showed that CG33145 exhibited galactosyltransferase activity in synthesis of terminal N-linked glycans. Phenotypic clustering, therefore, has potential for the functional prediction of novel GR genes. PMID:25940448

  9. Phenotype-based clustering of glycosylation-related genes by RNAi-mediated gene silencing

    PubMed Central

    Yamamoto-Hino, Miki; Yoshida, Hideki; Ichimiya, Tomomi; Sakamura, Sho; Maeda, Megumi; Kimura, Yoshinobu; Sasaki, Norihiko; Aoki-Kinoshita, Kiyoko F; Kinoshita-Toyoda, Akiko; Toyoda, Hidenao; Ueda, Ryu; Nishihara, Shoko; Goto, Satoshi

    2015-01-01

    Glycan structures are synthesized by a series of reactions conducted by glycosylation-related (GR) proteins such as glycosyltransferases, glycan-modifying enzymes, and nucleotide-sugar transporters. For example, the common core region of glycosaminoglycans (GAGs) is sequentially synthesized by peptide-O-xylosyltransferase, β1,4-galactosyltransferase I, β1,3-galactosyltransferase II, and β1,3-glucuronyltransferase. This raises the possibility that functional impairment of GR proteins involved in synthesis of the same glycan might result in the same phenotypic abnormality. To examine this possibility, comprehensive silencing of genes encoding GR and proteoglycan core proteins was conducted in Drosophila. Drosophila GR candidate genes (125) were classified into five functional groups for synthesis of GAGs, N-linked, O-linked, Notch-related, and unknown glycans. Spatiotemporally regulated silencing caused a range of malformed phenotypes that fell into three types: extra veins, thick veins, and depigmentation. The clustered phenotypes reflected the biosynthetic pathways of GAGs, Fringe-dependent glycan on Notch, and glycans placed at or near nonreducing ends (herein termed terminal domains of glycans). Based on the phenotypic clustering, CG33145 was predicted to be involved in formation of terminal domains. Our further analysis showed that CG33145 exhibited galactosyltransferase activity in synthesis of terminal N-linked glycans. Phenotypic clustering, therefore, has potential for the functional prediction of novel GR genes. PMID:25940448

  10. Klotho gene polymorphisms are related to colorectal cancer susceptibility

    PubMed Central

    Liu, Chang; Cui, Wei; Wang, Li; Yan, Lei; Ruan, Xinjian; Liu, Yanfang; Jia, Xiaoyan; Zhang, Xia

    2015-01-01

    Aim: The purpose of this study was to investigate the relationship of Klotho gene G-395A and C1818T polymorphisms with colorectal cancer (CRC) susceptibility. Methods: 125 CRC patients and 125 controls were enrolled in the study. G-395A and C1818T polymorphisms were genotyped with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technology. Haploview software was utilized to conduct linkage disequilibrium and haplotype analysis. Odds ratio (OR) and 95% confidence interval (95% CI) were used to analyze the correlation of genotypes and haplotypes with CRC susceptibility. Results: AA and GA genotypes of G-395A polymorphisms were related with CRC risk (AA: OR = 4.161, 95% CI = 1.437-12.053; GA: OR = 1.958, 95% CI = 1.133-3.385). The frequency of A allele was much higher in case group, compared with controls (31.2% vs.17.6%) and the value of OR AND 95% CI suggested that A allele served as a risk factor for CRC (OR = 2.123, 95% CI = 1.393-3.236). Haplotypes analysis indicated that A-C and A-T haplotypes were significantly associated with risk of CRC (OR = 1.822, 95% CI = 1.124-2.954; OR = 2.877, 95% CI = 1.340-6.176). Conclusion: G-395A polymorphism of Klotho gene could increase the risk of CRC. PMID:26261651

  11. Calcitonin Gene-Related Peptide: Physiology and Pathophysiology

    PubMed Central

    Russell, F. A.; King, R.; Smillie, S.-J.; Kodji, X.; Brain, S. D.

    2014-01-01

    Calcitonin gene-related peptide (CGRP) is a 37-amino acid neuropeptide. Discovered 30 years ago, it is produced as a consequence of alternative RNA processing of the calcitonin gene. CGRP has two major forms (α and β). It belongs to a group of peptides that all act on an unusual receptor family. These receptors consist of calcitonin receptor-like receptor (CLR) linked to an essential receptor activity modifying protein (RAMP) that is necessary for full functionality. CGRP is a highly potent vasodilator and, partly as a consequence, possesses protective mechanisms that are important for physiological and pathological conditions involving the cardiovascular system and wound healing. CGRP is primarily released from sensory nerves and thus is implicated in pain pathways. The proven ability of CGRP antagonists to alleviate migraine has been of most interest in terms of drug development, and knowledge to date concerning this potential therapeutic area is discussed. Other areas covered, where there is less information known on CGRP, include arthritis, skin conditions, diabetes, and obesity. It is concluded that CGRP is an important peptide in mammalian biology, but it is too early at present to know if new medicines for disease treatment will emerge from our knowledge concerning this molecule. PMID:25287861

  12. Breast and Prostate Cancer and Hormone-Related Gene Variant Study

    Cancer.gov

    The Breast and Prostate Cancer and Hormone-Related Gene Variant Study allows large-scale analyses of breast and prostate cancer risk in relation to genetic polymorphisms and gene-environment interactions that affect hormone metabolism.

  13. Glia-related genes and their contribution to schizophrenia.

    PubMed

    Wang, Chenyao; Aleksic, Branko; Ozaki, Norio

    2015-08-01

    Schizophrenia, a debilitating disease with 1% prevalence in the general population, is characterized by major neuropsychiatric symptoms, including delusions, hallucinations, and deficits in emotional and social behavior. Previous studies have directed their investigations on the mechanism of schizophrenia towards neuronal dysfunction and have defined schizophrenia as a 'neuron-centric' disorder. However, along with the development of genetics and systematic biology approaches in recent years, the crucial role of glial cells in the brain has also been shown to contribute to the etiopathology of schizophrenia. Here, we summarize comprehensive data that support the involvement of glial cells (including oligodendrocytes, astrocytes, and microglial cells) in schizophrenia and list several acknowledged glia-related genes or molecules associated with schizophrenia. Instead of purely an abnormality of neurons in schizophrenia, an additional 'glial perspective' provides us a novel and promising insight into the causal mechanisms and treatment for this disease.

  14. Charge transport in cancer-related genes and early carcinogenesis

    NASA Astrophysics Data System (ADS)

    Shih, Chi-Tin; Cheng, Yun-Yin; Wells, Stephen A.; Hsu, Ching-Ling; Römer, Rudolf A.

    2011-01-01

    The electronic transmission properties of DNA molecules are believed to play a significant role in many physical phenomena taking place in living organisms (Chakraborty, 2007) [1]. Here we study the charge transport (CT) properties of cancer-related genes, including some of the most important tumor suppressors. We find that the changes in averaged CT around the sites of pathogenic and cancerous mutations are statistically smaller than those on sites where pathogenic mutations have not been observed. The results suggest that CT might be an indicator to discriminate between pathogenic and non-pathogenic mutations at an early stage. Mutations which cause little change in CT may be more likely to occur, or more likely to be missed by damage-repair enzymes which probe CT, and are therefore more likely to persist and cause disease.

  15. Estrogen-related receptor {alpha} modulates the expression of adipogenesis-related genes during adipocyte differentiation

    SciTech Connect

    Ijichi, Nobuhiro; Ikeda, Kazuhiro; Horie-Inoue, Kuniko; Yagi, Ken; Okazaki, Yasushi; Inoue, Satoshi . E-mail: INOUE-GER@h.u-tokyo.ac.jp

    2007-07-06

    Estrogen-related receptor {alpha} (ERR{alpha}) is an orphan nuclear receptor that regulates cellular energy metabolism by modulating gene expression involved in fatty acid oxidation and mitochondrial biogenesis in brown adipose tissue. However, the physiological role of ERR{alpha} in adipogenesis and white adipose tissue development has not been well studied. Here, we show that ERR{alpha} and ERR{alpha}-related transcriptional coactivators, peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}) coactivator-1{alpha} (PGC-1{alpha}) and PGC-1{beta}, can be up-regulated in 3T3-L1 preadipocytes at mRNA levels under the adipogenic differentiation condition including the inducer of cAMP, glucocorticoid, and insulin. Gene knockdown by ERR{alpha}-specific siRNA results in mRNA down-regulation of fatty acid binding protein 4, PPAR{gamma}, and PGC-1{alpha} in 3T3-L1 cells in the adipogenesis medium. ERR{alpha} and PGC-1{beta} mRNA expression can be also up-regulated in another preadipocyte lineage DFAT-D1 cells and a pluripotent mesenchymal cell line C3H10T1/2 under the differentiation condition. Furthermore, stable expression of ERR{alpha} in 3T3-L1 cells up-regulates adipogenic marker genes and promotes triglyceride accumulation during 3T3-L1 differentiation. These results suggest that ERR{alpha} may play a critical role in adipocyte differentiation by modulating the expression of various adipogenesis-related genes.

  16. The retinoid-related orphan receptor alpha (RORA) gene and fear-related psychopathology

    PubMed Central

    Miller, Mark W.; Wolf, Erika J.; Logue, Mark W.; Baldwin, Clinton T.

    2013-01-01

    Background This study followed on findings from a recent genome-wide association study of PTSD that implicated the retinoid-related orphan receptor alpha (RORA) gene (Logue et al, 2012) by examining its relationship to broader array of disorders. Methods Using data from the same cohort (N = 540), we analyzed patterns of association between 606 single nucleotide polymorphisms (SNPs) spanning the RORA gene and comorbidity factors termed fear, distress (i.e., internalizing factors) and externalizing. Results Results showed that rs17303244 was associated with the fear component of internalizing (i.e., defined by symptoms of panic, agoraphobia, specific phobia, and obsessive-compulsive disorder) at a level of significance that withstood correction for gene-wide multiple testing. Limitations The primary limitations were the modest size of the cohort and the absence of a replication sample. Conclusions Results add to a growing literature implicating the RORA gene in a wide range of neuropsychiatric disorders and offer new insight into possible molecular mechanisms of the effects of traumatic stress on the brain and the role of genetic factors in those processes. PMID:24007783

  17. Function of the Chloroplast Hydrogenase in the Microalga Chlamydomonas: The Role of Hydrogenase and State Transitions during Photosynthetic Activation in Anaerobiosis

    PubMed Central

    Ghysels, Bart; Godaux, Damien; Matagne, René F.; Cardol, Pierre; Franck, Fabrice

    2013-01-01

    Like a majority of photosynthetic microorganisms, the green unicellular alga Chlamydomonas reinhardtii may encounter O2 deprived conditions on a regular basis. In response to anaerobiosis or in a respiration defective context, the photosynthetic electron transport chain of Chlamydomonas is remodeled by a state transition process to a conformation that favours the photoproduction of ATP at the expense of reductant synthesis. In some unicellular green algae including Chlamydomonas, anoxia also triggers the induction of a chloroplast-located, oxygen sensitive hydrogenase, which accepts electrons from reduced ferredoxin to convert protons into molecular hydrogen. Although microalgal hydrogen evolution has received much interest for its biotechnological potential, its physiological role remains unclear. By using specific Chlamydomonas mutants, we demonstrate that the state transition ability and the hydrogenase function are both critical for induction of photosynthesis in anoxia. These two processes are thus important for survival of the cells when they are transiently placed in an anaerobic environment. PMID:23717558

  18. Function of the chloroplast hydrogenase in the microalga Chlamydomonas: the role of hydrogenase and state transitions during photosynthetic activation in anaerobiosis.

    PubMed

    Ghysels, Bart; Godaux, Damien; Matagne, René F; Cardol, Pierre; Franck, Fabrice

    2013-01-01

    Like a majority of photosynthetic microorganisms, the green unicellular alga Chlamydomonas reinhardtii may encounter O2 deprived conditions on a regular basis. In response to anaerobiosis or in a respiration defective context, the photosynthetic electron transport chain of Chlamydomonas is remodeled by a state transition process to a conformation that favours the photoproduction of ATP at the expense of reductant synthesis. In some unicellular green algae including Chlamydomonas, anoxia also triggers the induction of a chloroplast-located, oxygen sensitive hydrogenase, which accepts electrons from reduced ferredoxin to convert protons into molecular hydrogen. Although microalgal hydrogen evolution has received much interest for its biotechnological potential, its physiological role remains unclear. By using specific Chlamydomonas mutants, we demonstrate that the state transition ability and the hydrogenase function are both critical for induction of photosynthesis in anoxia. These two processes are thus important for survival of the cells when they are transiently placed in an anaerobic environment. PMID:23717558

  19. [Genes related with male gonadal morphogenesis in mammals].

    PubMed

    Wu, Jie; Wang, Feng

    2008-04-01

    Gene expressions are sex-specific in the sex development of mammals. Different genes express in different phases and tend to change with the time. The functions of some genes, such as SRY, SOX9, SOX8, DAX1, and FGF9, have already been defined in male gonadal morphogenesis. This paper presents a review of the genes involved in the formation of the male gonad in mammals. PMID:18481432

  20. Powerful fermentative hydrogen evolution of photosynthate in the cyanobacterium Lyngbya aestuarii BL J mediated by a bidirectional hydrogenase

    PubMed Central

    Kothari, Ankita; Parameswaran, Prathap; Garcia-Pichel, Ferran

    2014-01-01

    Cyanobacteria are considered good models for biohydrogen production because they are relatively simple organisms with a demonstrable ability to generate H2 under certain physiological conditions. However, most produce only little H2, revert readily to H2 consumption, and suffer from hydrogenase sensitivity to O2. Strains of the cyanobacteria Lyngbya aestuarii and Microcoleus chthonoplastes obtained from marine intertidal cyanobacterial mats were recently found to display much better H2 production potential. Because of their ecological origin in environments that become quickly anoxic in the dark, we hypothesized that this differential ability may have evolved to serve a role in the fermentation of the photosynthate. Here we show that, when forced to ferment internal substrate, these cyanobacteria display desirable characteristics of physiological H2 production. Among them, the strain L. aestuarii BL J had the fastest specific rates and attained the highest H2 concentrations during fermentation of photosynthate, which proceeded via a mixed acid fermentation pathway to yield acetate, ethanol, lactate, H2, CO2, and pyruvate. Contrary to expectations, the H2 yield per mole of glucose was only average compared to that of other cyanobacteria. Thermodynamic analyses point to the use of electron donors more electronegative than NAD(P)H in Lyngbya hydrogenases as the basis for its strong H2 production ability. In any event, the high specific rates and H2 concentrations coupled with the lack of reversibility of the enzyme, at the expense of internal, photosynthetically generated reductants, makes L. aestuarii BL J and/or its enzymes, a potentially feasible platform for large-scale H2 production. PMID:25540642

  1. Odd-skipped related 2 regulates genes related to proliferation and development

    SciTech Connect

    Kawai, Shinji; Abiko, Yoshimitsu; Amano, Atsuo

    2010-07-23

    Cell proliferation is a biological process in which chromosomes replicate in one cell and equally divide into two daughter cells. Our previous findings suggested that Odd-skipped related 2 (Osr2) plays an important role in cellular quiescence and proliferation under epigenetic regulation. However, the mechanism used by Osr2 to establish and maintain proliferation is unknown. To examine the functional role of Osr2 in cell proliferation, we analyzed its downstream target genes using microarray analysis following adenovirus-induced overexpression of Osr2 as well as knockdown with Osr2 siRNA, which showed that Osr2 regulates a multitude of genes involved in proliferation and the cell cycle, as well as development. Additional proliferation assays also indicated that Osr2 likely functions to elicit cell proliferation. Together, these results suggest that Osr2 plays important roles in proliferation and development.

  2. Evolution of xyloglucan-related genes in green plants

    PubMed Central

    2010-01-01

    Background The cell shape and morphology of plant tissues are intimately related to structural modifications in the primary cell wall that are associated with key processes in the regulation of cell growth and differentiation. The primary cell wall is composed mainly of cellulose immersed in a matrix of hemicellulose, pectin, lignin and some structural proteins. Xyloglucan is a hemicellulose polysaccharide present in the cell walls of all land plants (Embryophyta) and is the main hemicellulose in non-graminaceous angiosperms. Results In this work, we used a comparative genomic approach to obtain new insights into the evolution of the xyloglucan-related enzymatic machinery in green plants. Detailed phylogenetic analyses were done for enzymes involved in xyloglucan synthesis (xyloglucan transglycosylase/hydrolase, α-xylosidase, β-galactosidase, β-glucosidase and α-fucosidase) and mobilization/degradation (β-(1→4)-glucan synthase, α-fucosyltransferases, β-galactosyltransferases and α-xylosyl transferase) based on 12 fully sequenced genomes and expressed sequence tags from 29 species of green plants. Evidence from Chlorophyta and Streptophyta green algae indicated that part of the Embryophyta xyloglucan-related machinery evolved in an aquatic environment, before land colonization. Streptophyte algae have at least three enzymes of the xyloglucan machinery: xyloglucan transglycosylase/hydrolase, β-(1→4)-glucan synthase from the celullose synthase-like C family and α-xylosidase that is also present in chlorophytes. Interestingly, gymnosperm sequences orthologs to xyloglucan transglycosylase/hydrolases with exclusively hydrolytic activity were also detected, suggesting that such activity must have emerged within the last common ancestor of spermatophytes. There was a positive correlation between the numbers of founder genes within each gene family and the complexity of the plant cell wall. Conclusions Our data support the idea that a primordial xyloglucan

  3. Flexible plastic bioreactors for photobiological hydrogen production by hydrogenase-deficient cyanobacteria.

    PubMed

    Kitashima, Masaharu; Masukawa, Hajime; Sakurai, Hidehiro; Inoue, Kazuhito

    2012-01-01

    Uptake hydrogenase mutant cells of the cyanobacterium Nostoc sp. PCC 7422 photobiologically produced H(2) catalyzed by nitrogenase for several days in H(2)-barrier transparent plastic bags, and accumulated H(2) in the presence of O(2) evolved by photosynthesis. Their H(2) production activity was higher in the sealed flexible bags than in stoppered serum bottles of fixed gas volume.

  4. The quest for a functional substrate access tunnel in FeFe hydrogenase.

    PubMed

    Lautier, Thomas; Ezanno, Pierre; Baffert, Carole; Fourmond, Vincent; Cournac, Laurent; Fontecilla-Camps, Juan C; Soucaille, Philippe; Bertrand, Patrick; Meynial-Salles, Isabelle; Léger, Christophe

    2011-01-01

    We investigated di-hydrogen transport between the solvent and the active site of FeFe hydrogenases. Substrate channels supposedly exist and serve various functions in certain redox enzymes which use or produce O2, H2, NO, CO, or N2, but the preferred paths have not always been unambiguously identified, and whether a continuous, permanent channel is an absolute requirement for transporting diatomic molecules is unknown. Here, we review the literature on gas channels in proteins and enzymes and we report on the use of site-directed mutagenesis and various kinetic methods, which proved useful for characterizing substrate access to the active site of NiFe hydrogenase to test the putative "static" H2 channel of FeFe hydrogenases. We designed 8 mutations in attempts to interfere with intramolecular diffusion by remodeling this putative route in Clostridium acetobutylicum FeFe hydrogenase, and we observed that none of them has a strong effect on any of the enzyme's kinetic properties. We suggest that H2 may diffuse either via transient cavities, or along a conserved water-filled channel. Nitrogenase sets a precedent for the involvement of a hydrophilic channel to conduct hydrophobic molecules.

  5. Hydrogenase activity of mineral-associated and suspended populations of Desulfovibrio Desulfuricans Essex 6

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The interactions between sulfate-reducing microorganisms and iron oxides influence a number of important redox-sensitive biogeochemical processes including the formation of iron sulfides. Enzymes, such as hydrogenase which catalyze the reversible oxidation of molecular hydrogen, are known to mediate...

  6. Lyophilization protects [FeFe]-hydrogenases against O2-induced H-cluster degradation

    PubMed Central

    Noth, Jens; Kositzki, Ramona; Klein, Kathrin; Winkler, Martin; Haumann, Michael; Happe, Thomas

    2015-01-01

    Nature has developed an impressive repertoire of metal-based enzymes that perform complex chemical reactions under moderate conditions. Catalysts that produce molecular hydrogen (H2) are particularly promising for renewable energy applications. Unfortunately, natural and chemical H2-catalysts are often irreversibly degraded by molecular oxygen (O2). Here we present a straightforward procedure based on freeze-drying (lyophilization), that turns [FeFe]-hydrogenases, which are excellent H2-producers, but typically extremely O2-sensitive in solution, into enzymes that are fully resistant against O2. Complete dryness protects and conserves both, the [FeFe]-hydrogenase proteins and their inorganic active-site cofactor (H-cluster), when exposed to 100% O2 for days. The full H2-formation capacity is restored after solvation of the lyophilized enzymes. However, even minimal moisturizing re-establishes O2-sensitivity. The dry [FeFe]-hydrogenase material is superior also for advanced spectroscopic investigations on the H-cluster reaction mechanism. Our method provides a convenient way for long-term storage and impacts on potential biotechnological hydrogen production applications of hydrogenase enzymes. PMID:26364994

  7. A redox hydrogel protects hydrogenase from high-potential deactivation and oxygen damage

    NASA Astrophysics Data System (ADS)

    Plumeré, Nicolas; Rüdiger, Olaf; Oughli, Alaa Alsheikh; Williams, Rhodri; Vivekananthan, Jeevanthi; Pöller, Sascha; Schuhmann, Wolfgang; Lubitz, Wolfgang

    2014-09-01

    Hydrogenases are nature's efficient catalysts for both the generation of energy via oxidation of molecular hydrogen and the production of hydrogen via the reduction of protons. However, their O2 sensitivity and deactivation at high potential limit their applications in practical devices, such as fuel cells. Here, we show that the integration of an O2-sensitive hydrogenase into a specifically designed viologen-based redox polymer protects the enzyme from O2 damage and high-potential deactivation. Electron transfer between the polymer-bound viologen moieties controls the potential applied to the active site of the hydrogenase and thus insulates the enzyme from excessive oxidative stress. Under catalytic turnover, electrons provided from the hydrogen oxidation reaction induce viologen-catalysed O2 reduction at the polymer surface, thus providing self-activated protection from O2. The advantages of this tandem protection are demonstrated using a single-compartment biofuel cell based on an O2-sensitive hydrogenase and H2/O2 mixed feed under anode-limiting conditions.

  8. Metabolic control of Clostridium thermocellum via inhibition of hydrogenase activity and the glucose transport rate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Clostridium thermocellum has the ability to catabolize cellulosic biomass into ethanol, but acetic acid, lactic acid, carbon dioxide, and hydrogen gas (H2) are also produced. The effect of hydrogenase inhibitors (H2, carbon monoxide (CO) and methyl viologen) on product selectivity was investigated....

  9. Lyophilization protects [FeFe]-hydrogenases against O2-induced H-cluster degradation.

    PubMed

    Noth, Jens; Kositzki, Ramona; Klein, Kathrin; Winkler, Martin; Haumann, Michael; Happe, Thomas

    2015-09-14

    Nature has developed an impressive repertoire of metal-based enzymes that perform complex chemical reactions under moderate conditions. Catalysts that produce molecular hydrogen (H2) are particularly promising for renewable energy applications. Unfortunately, natural and chemical H2-catalysts are often irreversibly degraded by molecular oxygen (O2). Here we present a straightforward procedure based on freeze-drying (lyophilization), that turns [FeFe]-hydrogenases, which are excellent H2-producers, but typically extremely O2-sensitive in solution, into enzymes that are fully resistant against O2. Complete dryness protects and conserves both, the [FeFe]-hydrogenase proteins and their inorganic active-site cofactor (H-cluster), when exposed to 100% O2 for days. The full H2-formation capacity is restored after solvation of the lyophilized enzymes. However, even minimal moisturizing re-establishes O2-sensitivity. The dry [FeFe]-hydrogenase material is superior also for advanced spectroscopic investigations on the H-cluster reaction mechanism. Our method provides a convenient way for long-term storage and impacts on potential biotechnological hydrogen production applications of hydrogenase enzymes.

  10. Nickel-Substituted Rubredoxin as a Minimal Enzyme Model for Hydrogenase.

    PubMed

    Slater, Jeffrey W; Shafaat, Hannah S

    2015-09-17

    A simple, functional mimic of [NiFe] hydrogenases based on a nickel-substituted rubredoxin (NiRd) protein is reported. NiRd is capable of light-initiated and solution-phase hydrogen production and demonstrates high electrocatalytic activity using protein film voltammetry. The catalytic voltammograms are modeled using analytical expressions developed for hydrogenase enzymes, revealing maximum turnover frequencies of approximately 20-100 s(-1) at 4 °C with an overpotential of 540 mV. These rates are directly comparable to those observed for [NiFe] hydrogenases under similar conditions. Like the native enzymes, the proton reduction activity of NiRd is strongly inhibited by carbon monoxide. This engineered rubredoxin-based enzyme is chemically and thermally robust, easily accessible, and highly tunable. These results have implications for understanding the enzymatic mechanisms of native hydrogenases, and, using NiRd as a scaffold, it will be possible to optimize this catalyst for application in sustainable fuel generation. PMID:26722748

  11. Identification of hepatic microvascular adhesion-related genes of human colon cancer cells using random homozygous gene perturbation.

    PubMed

    Márquez, Joana; Kohli, Manu; Arteta, Beatriz; Chang, Shaojing; Li, Wu-Bo; Goldblatt, Michael; Vidal-Vanaclocha, Fernando

    2013-11-01

    Random homozygous gene perturbation (RHGP), in combination with liver sinusoidal endothelial cell (LSEC) adhesion screening of clonal colon cancer cells with perturbed genes, was used to identify genes contributing to the hepatic microvascular adhesion of colon cancer cells. Plasmid vector encoding transactivator and gene search vector were transfected into HT-29 human colorectal cancer cells to create a HT-29 RHGP cell library; the adhesion of these library cells to primary cultured mouse LSEC significantly decreased in the presence of RSL1 ligand (inducer), indicating that most of the genes contributing to HT-29 adhesion to LSEC were altered. Next, HT-29 RHGP cell library fractions with upregulated or silenced LSEC adhesion-related genes were isolated. Around 160 clones having altered expression in LSEC adhesion-related genes were obtained, and nine relevant protein-coding genes were identified. Some were proadhesive genes detected because of their overexpression in adherent HT-29 cells (DGCR8 and EFEMP1 genes) and their silenced status in nonadherent HT-29 cells (DGKE, DPY19L1, KIAA0753, PVR and USP11 genes). Others were antiadhesive genes detected because of their overexpression in nonadherent HT-29 cells (ITPKC gene) and their silenced status in adherent HT-29 cells (PPP6R2 gene). Silencing of PVR, DGCR8 and EFEMP1 genes decreased adhesion to LSEC and hepatic microvascular retention of HT-29 cells. The results conclude that RHGP was a valuable strategy for the discovery of mechanisms regulating microvascular adhesion of circulating colon cancer cells before hepatic metastasis formation. Identified genes may contribute to understand the metastatic process of colon cancer and to discovering molecular targets for hepatic metastasis therapeutics.

  12. BRONCO: Biomedical entity Relation ONcology COrpus for extracting gene-variant-disease-drug relations.

    PubMed

    Lee, Kyubum; Lee, Sunwon; Park, Sungjoon; Kim, Sunkyu; Kim, Suhkyung; Choi, Kwanghun; Tan, Aik Choon; Kang, Jaewoo

    2016-01-01

    Comprehensive knowledge of genomic variants in a biological context is key for precision medicine. As next-generation sequencing technologies improve, the amount of literature containing genomic variant data, such as new functions or related phenotypes, rapidly increases. Because numerous articles are published every day, it is almost impossible to manually curate all the variant information from the literature. Many researchers focus on creating an improved automated biomedical natural language processing (BioNLP) method that extracts useful variants and their functional information from the literature. However, there is no gold-standard data set that contains texts annotated with variants and their related functions. To overcome these limitations, we introduce a Biomedical entity Relation ONcology COrpus (BRONCO) that contains more than 400 variants and their relations with genes, diseases, drugs and cell lines in the context of cancer and anti-tumor drug screening research. The variants and their relations were manually extracted from 108 full-text articles. BRONCO can be utilized to evaluate and train new methods used for extracting biomedical entity relations from full-text publications, and thus be a valuable resource to the biomedical text mining research community. Using BRONCO, we quantitatively and qualitatively evaluated the performance of three state-of-the-art BioNLP methods. We also identified their shortcomings, and suggested remedies for each method. We implemented post-processing modules for the three BioNLP methods, which improved their performance.Database URL:http://infos.korea.ac.kr/bronco. PMID:27074804

  13. BRONCO: Biomedical entity Relation ONcology COrpus for extracting gene-variant-disease-drug relations

    PubMed Central

    Lee, Kyubum; Lee, Sunwon; Park, Sungjoon; Kim, Sunkyu; Kim, Suhkyung; Choi, Kwanghun; Tan, Aik Choon; Kang, Jaewoo

    2016-01-01

    Comprehensive knowledge of genomic variants in a biological context is key for precision medicine. As next-generation sequencing technologies improve, the amount of literature containing genomic variant data, such as new functions or related phenotypes, rapidly increases. Because numerous articles are published every day, it is almost impossible to manually curate all the variant information from the literature. Many researchers focus on creating an improved automated biomedical natural language processing (BioNLP) method that extracts useful variants and their functional information from the literature. However, there is no gold-standard data set that contains texts annotated with variants and their related functions. To overcome these limitations, we introduce a Biomedical entity Relation ONcology COrpus (BRONCO) that contains more than 400 variants and their relations with genes, diseases, drugs and cell lines in the context of cancer and anti-tumor drug screening research. The variants and their relations were manually extracted from 108 full-text articles. BRONCO can be utilized to evaluate and train new methods used for extracting biomedical entity relations from full-text publications, and thus be a valuable resource to the biomedical text mining research community. Using BRONCO, we quantitatively and qualitatively evaluated the performance of three state-of-the-art BioNLP methods. We also identified their shortcomings, and suggested remedies for each method. We implemented post-processing modules for the three BioNLP methods, which improved their performance. Database URL: http://infos.korea.ac.kr/bronco PMID:27074804

  14. Apoptosis-related genes change their expression with age and hearing loss in the mouse cochlea.

    PubMed

    Tadros, Sherif F; D'Souza, Mary; Zhu, Xiaoxia; Frisina, Robert D

    2008-11-01

    To understand possible causative roles of apoptosis gene regulation in age-related hearing loss (presbycusis), apoptotic gene expression patterns in the CBA mouse cochlea of four different age and hearing loss groups were compared, using GeneChip and real-time (qPCR) microarrays. GeneChip transcriptional expression patterns of 318 apoptosis-related genes were analyzed. Thirty eight probes (35 genes) showed significant differences in expression. The significant gene families include Caspases, B-cell leukemia/lymphoma2 family, P53, Calpains, Mitogen activated protein kinase family, Jun oncogene, Nuclear factor of kappa light chain gene enhancer in B-cells inhibitor-related and tumor necrosis factor-related genes. The GeneChip results of 31 genes were validated using the new TaqMan Low Density Array (TLDA). Eight genes showed highly correlated results with the GeneChip data. These genes are: activating transcription factor3, B-cell leukemia/lymphoma2, Bcl2-like1, caspase4 apoptosis-related cysteine protease 4, Calpain2, dual specificity phosphatase9, tumor necrosis factor receptor superfamily member12a, and Tumor necrosis factor superfamily member13b, suggesting they may play critical roles in inner ear aging.

  15. Identification of Hub Genes Related to the Recovery Phase of Irradiation Injury by Microarray and Integrated Gene Network Analysis

    PubMed Central

    Zhang, Jing; Yang, Yue; Wang, Yin; Zhang, Jinyuan; Wang, Zejian; Yin, Ming; Shen, Xudong

    2011-01-01

    Background Irradiation commonly causes long-term bone marrow injury charactertized by defective HSC self-renewal and a decrease in HSC reserve. However, the effect of high-dose IR on global gene expression during bone marrow recovery remains unknown. Methodology Microarray analysis was used to identify differentially expressed genes that are likely to be critical for bone marrow recovery. Multiple bioinformatics analyses were conducted to identify key hub genes, pathways and biological processes. Principal Findings 1) We identified 1302 differentially expressed genes in murine bone marrow at 3, 7, 11 and 21 days after irradiation. Eleven of these genes are known to be HSC self-renewal associated genes, including Adipoq, Ccl3, Ccnd1, Ccnd2, Cdkn1a, Cxcl12, Junb, Pten, Tal1, Thy1 and Tnf; 2) These 1302 differentially expressed genes function in multiple biological processes of immunity, including hematopoiesis and response to stimuli, and cellular processes including cell proliferation, differentiation, adhesion and signaling; 3) Dynamic Gene Network analysis identified a subgroup of 25 core genes that participate in immune response, regulation of transcription and nucleosome assembly; 4) A comparison of our data with known irradiation-related genes extracted from literature showed 42 genes that matched the results of our microarray analysis, thus demonstrated consistency between studies; 5) Protein-protein interaction network and pathway analyses indicated several essential protein-protein interactions and signaling pathways, including focal adhesion and several immune-related signaling pathways. Conclusions Comparisons to other gene array datasets indicate that global gene expression profiles of irradiation damaged bone marrow show significant differences between injury and recovery phases. Our data suggest that immune response (including hematopoiesis) can be considered as a critical biological process in bone marrow recovery. Several critical hub genes that are

  16. Gene-Environment Interactions of Circadian-Related Genes for Cardiometabolic Traits

    PubMed Central

    Follis, Jack L.; Smith, Caren E.; Tanaka, Toshiko; Garaulet, Marta; Gottlieb, Daniel J.; Hruby, Adela; Jacques, Paul F.; Kiefte-de Jong, Jessica C.; Lamon-Fava, Stefania; Scheer, Frank A.J.L.; Bartz, Traci M.; Kovanen, Leena; Wojczynski, Mary K.; Frazier-Wood, Alexis C.; Ahluwalia, Tarunveer S.; Perälä, Mia-Maria; Jonsson, Anna; Muka, Taulant; Kalafati, Ioanna P.; Mikkilä, Vera; Ordovás, José M.

    2015-01-01

    OBJECTIVE Common circadian-related gene variants associate with increased risk for metabolic alterations including type 2 diabetes. However, little is known about whether diet and sleep could modify associations between circadian-related variants (CLOCK-rs1801260, CRY2-rs11605924, MTNR1B-rs1387153, MTNR1B-rs10830963, NR1D1-rs2314339) and cardiometabolic traits (fasting glucose [FG], HOMA-insulin resistance, BMI, waist circumference, and HDL-cholesterol) to facilitate personalized recommendations. RESEARCH DESIGN AND METHODS We conducted inverse-variance weighted, fixed-effect meta-analyses of results of adjusted associations and interactions between dietary intake/sleep duration and selected variants on cardiometabolic traits from 15 cohort studies including up to 28,190 participants of European descent from the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) Consortium. RESULTS We observed significant associations between relative macronutrient intakes and glycemic traits and short sleep duration (<7 h) and higher FG and replicated known MTNR1B associations with glycemic traits. No interactions were evident after accounting for multiple comparisons. However, we observed nominally significant interactions (all P < 0.01) between carbohydrate intake and MTNR1B-rs1387153 for FG with a 0.003 mmol/L higher FG with each additional 1% carbohydrate intake in the presence of the T allele, between sleep duration and CRY2-rs11605924 for HDL-cholesterol with a 0.010 mmol/L higher HDL-cholesterol with each additional hour of sleep in the presence of the A allele, and between long sleep duration (≥9 h) and MTNR1B-rs1387153 for BMI with a 0.60 kg/m2 higher BMI with long sleep duration in the presence of the T allele relative to normal sleep duration (≥7 to <9 h). CONCLUSIONS Our results suggest that lower carbohydrate intake and normal sleep duration may ameliorate cardiometabolic abnormalities conferred by common circadian-related genetic variants

  17. An Unsupervised Approach to Predict Functional Relations between Genes Based on Expression Data

    PubMed Central

    Altaf-Ul-Amin, Md.; Sato, Tetsuo; Ono, Naoaki; Kanaya, Shigehiko

    2014-01-01

    This work presents a novel approach to predict functional relations between genes using gene expression data. Genes may have various types of relations between them, for example, regulatory relations, or they may be concerned with the same protein complex or metabolic/signaling pathways and obviously gene expression data should contain some clues to such relations. The present approach first digitizes the log-ratio type gene expression data of S. cerevisiae to a matrix consisting of 1, 0, and −1 indicating highly expressed, no major change, and highly suppressed conditions for genes, respectively. For each gene pair, a probability density mass function table is constructed indicating nine joint probabilities. Then gene pairs were selected based on linear and probabilistic relation between their profiles indicated by the sum of probability density masses in selected points. The selected gene pairs share many Gene Ontology terms. Furthermore a network is constructed by selecting a large number of gene pairs based on FDR analysis and the clustering of the network generates many modules rich with similar function genes. Also, the promoters of the gene sets in many modules are rich with binding sites of known transcription factors indicating the effectiveness of the proposed approach in predicting regulatory relations. PMID:24800208

  18. Hepatic oxidoreduction-related genes are upregulated by administration of hydrogen-saturated drinking water.

    PubMed

    Nakai, Yuji; Sato, Bunpei; Ushiama, Shota; Okada, Shinji; Abe, Keiko; Arai, Soichi

    2011-01-01

    The effects of the administration of molecular hydrogen-saturated drinking water (hydrogen water) on hepatic gene expression were investigated in rats. Using DNA microarrays, 548 upregulated and 695 downregulated genes were detected in the liver after 4 weeks of administration of hydrogen water. Gene Ontology analysis revealed that genes for oxidoreduction-related proteins, including hydroxymethylglutaryl CoA reductase, were significantly enriched in the upregulated genes. PMID:21512236

  19. Selection of reference genes for gene expression studies related to intramuscular fat deposition in Capra hircus skeletal muscle.

    PubMed

    Zhu, Wuzheng; Lin, Yaqiu; Liao, Honghai; Wang, Yong

    2015-01-01

    The identification of suitable reference genes is critical for obtaining reliable results from gene expression studies using quantitative real-time PCR (qPCR) because the expression of reference genes may vary considerably under different experimental conditions. In most cases, however, commonly used reference genes are employed in data normalization without proper validation, which may lead to incorrect data interpretation. Here, we aim to select a set of optimal reference genes for the accurate normalization of gene expression associated with intramuscular fat (IMF) deposition during development. In the present study, eight reference genes (PPIB, HMBS, RPLP0, B2M, YWHAZ, 18S, GAPDH and ACTB) were evaluated by three different algorithms (geNorm, NormFinder and BestKeeper) in two types of muscle tissues (longissimus dorsi muscle and biceps femoris muscle) across different developmental stages. All three algorithms gave similar results. PPIB and HMBS were identified as the most stable reference genes, while the commonly used reference genes 18S and GAPDH were the most variably expressed, with expression varying dramatically across different developmental stages. Furthermore, to reveal the crucial role of appropriate reference genes in obtaining a reliable result, analysis of PPARG expression was performed by normalization to the most and the least stable reference genes. The relative expression levels of PPARG normalized to the most stable reference genes greatly differed from those normalized to the least stable one. Therefore, evaluation of reference genes must be performed for a given experimental condition before the reference genes are used. PPIB and HMBS are the optimal reference genes for analysis of gene expression associated with IMF deposition in skeletal muscle during development.

  20. [Structure and function of neural plasticity-related gene products].

    PubMed

    Yamagata, K; Sugiura, H; Suzuki, K

    1998-08-01

    We have isolated novel immediate early genes (IEGs) from the hippocampus by differential cloning techniques. These mRNAs are induced by synaptic activity and translated into proteins that may affect neural function. We have analyzed a variety of "effector" immediate early genes. These mRNAs encode: 1) cytoplasmic proteins, such as cyclooxygenase-2, a small G protein, Rheb, and a cytoskeleton-associated protein, Arc; 2) membrane-bound proteins, such as the cell adhesion protein Arcadlin, and a neurite-outgrowth protein, Neuritin; and 3) a secreted protein, Narp. We hypothesize that physiological stimulation induces "effector" proteins that might strengthen synaptic connections of activated synapses. In contrast, pathological conditions such as epilepsy or drug addiction may accelerate overproduction of these gene products, which cause abnormal synapse formation. Gene targeting and in vivo gene transfer techniques are required to prove this hypothesis. PMID:9866829

  1. Redox reactions of [FeFe]-hydrogenase models containing an internal amine and a pendant phosphine.

    PubMed

    Zheng, Dehua; Wang, Mei; Chen, Lin; Wang, Ning; Sun, Licheng

    2014-02-01

    A diiron dithiolate complex with a pendant phosphine coordinated to one of the iron centers, [(μ-SCH2)2N(CH2C6H4-o-PPh2){Fe2(CO)5}] (1), was prepared and structurally characterized. The pendant phosphine is dissociated together with a CO ligand in the presence of excess PMe3, to afford [(μ-SCH2)2N(CH2C6H4-o-PPh2){Fe(CO)2(PMe3)}2] (2). Redox reactions of 2 and related complexes were studied in detail by in situ IR spectroscopy. A series of new Fe(II)Fe(I) ([3](+) and [6](+)), Fe(II)Fe(II) ([4](2+)), and Fe(I)Fe(I) (5) complexes relevant to Hox, Hox(CO), and Hred states of the [FeFe]-hydrogenase active site were detected. Among these complexes, the molecular structures of the diferrous complex [4](2+) with the internal amine and the pendant phosphine co-coordinated to the same iron center and the triphosphine diiron complex 5 were determined by X-ray crystallography. To make a comparison, the redox reactions of an analogous complex, [(μ-SCH2)2N(CH2C6H5){Fe(CO)2(PMe3)}2] (7), were also investigated by in situ IR spectroscopy in the absence or presence of extrinsic PPh3, which has no influence on the oxidation reaction of 7. The pendant phosphine in the second coordination sphere makes the redox reaction of 2 different from that of its analogue 7.

  2. A redox hydrogel protects the O2 -sensitive [FeFe]-hydrogenase from Chlamydomonas reinhardtii from oxidative damage.

    PubMed

    Oughli, Alaa Alsheikh; Conzuelo, Felipe; Winkler, Martin; Happe, Thomas; Lubitz, Wolfgang; Schuhmann, Wolfgang; Rüdiger, Olaf; Plumeré, Nicolas

    2015-10-12

    The integration of sensitive catalysts in redox matrices opens up the possibility for their protection from deactivating molecules such as O2 . [FeFe]-hydrogenases are enzymes catalyzing H2 oxidation/production which are irreversibly deactivated by O2 . Therefore, their use under aerobic conditions has never been achieved. Integration of such hydrogenases in viologen-modified hydrogel films allows the enzyme to maintain catalytic current for H2 oxidation in the presence of O2 , demonstrating a protection mechanism independent of reactivation processes. Within the hydrogel, electrons from the hydrogenase-catalyzed H2 oxidation are shuttled to the hydrogel-solution interface for O2 reduction. Hence, the harmful O2 molecules do not reach the hydrogenase. We illustrate the potential applications of this protection concept with a biofuel cell under H2 /O2 mixed feed.

  3. Isolation and characterization of Agouti: a diabetes/obesity related gene

    DOEpatents

    Woychik, Richard P.

    2000-06-27

    The present invention relates to the cloning and expression of the Agouti gene and analogous genes in transformed, transfected and transgenic mice. The present invention provides an animal model for the study of diabetes, obesity and tumors for the testing of potential therapeutic agents. The present invention provides oligonucleotide probes for the detection of the Agouti gene and mutations in the gene. The present invention also relates to the isolation and recombinant production of the Agouti gene product, production of antibodies to the Agouti gene product and their use as diagnostic and therapeutic agents.

  4. Isolation and characterization of Agouti: a diabetes/obesity related gene

    DOEpatents

    Woychik, Richard P.

    1998-01-01

    The present invention relates to the cloning and expression of the Agouti gene and analogous genes in transformed, transfected and transgenic mice. The present invention provides an animal model for the study of diabetes, obesity and tumors for the testing of potential therapeutic agents. The present invention provides oligonucleotide probes for the detection of the Agouti gene and mutations in the gene. The present invention also relates to the isolation and recombinant production of the Agouti gene product, production of antibodies to the Agouti gene product and their use as diagnostic and therapeutic agents.

  5. Purification and Characterization of the [NiFe]-Hydrogenase of Shewanella oneidensis MR-1 ▿

    PubMed Central

    Shi, Liang; Belchik, Sara M.; Plymale, Andrew E.; Heald, Steve; Dohnalkova, Alice C.; Sybirna, Kateryna; Bottin, Hervé; Squier, Thomas C.; Zachara, John M.; Fredrickson, James K.

    2011-01-01

    Shewanella oneidensis MR-1 possesses a periplasmic [NiFe]-hydrogenase (MR-1 [NiFe]-H2ase) that has been implicated in H2 production and oxidation as well as technetium [Tc(VII)] reduction. To characterize the roles of MR-1 [NiFe]-H2ase in these proposed reactions, the genes encoding both subunits of MR-1 [NiFe]-H2ase were cloned and then expressed in an MR-1 mutant without hyaB and hydA genes. Expression of recombinant MR-1 [NiFe]-H2ase in trans restored the mutant's ability to produce H2 at 37% of that for the wild type. Following purification, MR-1 [NiFe]-H2ase coupled H2 oxidation to reduction of Tc(VII)O4− and methyl viologen. Change of the buffers used affected MR-1 [NiFe]-H2ase-mediated reduction of Tc(VII)O4− but not methyl viologen. Under the conditions tested, all Tc(VII)O4− used was reduced in Tris buffer, while in HEPES buffer, only 20% of Tc(VII)O4− was reduced. The reduced products were soluble in Tris buffer but insoluble in HEPES buffer. Transmission electron microscopy analysis revealed that Tc precipitates reduced in HEPES buffer were aggregates of crystallites with diameters of ∼5 nm. Measurements with X-ray absorption near-edge spectroscopy revealed that the reduction products were a mixture of Tc(IV) and Tc(V) in Tris buffer but only Tc(IV) in HEPES buffer. Measurements with extended X-ray adsorption fine structure showed that while the Tc bonding environment in Tris buffer could not be determined, the Tc(IV) product in HEPES buffer was very similar to Tc(IV)O2·nH2O, which was also the product of Tc(VII)O4− reduction by MR-1 cells. These results shows for the first time that MR-1 [NiFe]-H2ase catalyzes Tc(VII)O4− reduction directly by coupling to H2 oxidation. PMID:21724888

  6. Ossification of the posterior longitudinal ligament related genes identification using microarray gene expression profiling and bioinformatics analysis.

    PubMed

    He, Hailong; Mao, Lingzhou; Xu, Peng; Xi, Yanhai; Xu, Ning; Xue, Mingtao; Yu, Jiangming; Ye, Xiaojian

    2014-01-10

    Ossification of the posterior longitudinal ligament (OPLL) is a kind of disease with physical barriers and neurological disorders. The objective of this study was to explore the differentially expressed genes (DEGs) in OPLL patient ligament cells and identify the target sites for the prevention and treatment of OPLL in clinic. Gene expression data GSE5464 was downloaded from Gene Expression Omnibus; then DEGs were screened by limma package in R language, and changed functions and pathways of OPLL cells compared to normal cells were identified by DAVID (The Database for Annotation, Visualization and Integrated Discovery); finally, an interaction network of DEGs was constructed by string. A total of 1536 DEGs were screened, with 31 down-regulated and 1505 up-regulated genes. Response to wounding function and Toll-like receptor signaling pathway may involve in the development of OPLL. Genes, such as PDGFB, PRDX2 may involve in OPLL through response to wounding function. Toll-like receptor signaling pathway enriched genes such as TLR1, TLR5, and TLR7 may involve in spine cord injury in OPLL. PIK3R1 was the hub gene in the network of DEGs with the highest degree; INSR was one of the most closely related genes of it. OPLL related genes screened by microarray gene expression profiling and bioinformatics analysis may be helpful for elucidating the mechanism of OPLL.

  7. The biosynthetic routes for carbon monoxide and cyanide in the Ni-Fe active site of hydrogenases are different.

    PubMed

    Roseboom, Winfried; Blokesch, Melanie; Böck, August; Albracht, Simon P J

    2005-01-17

    The incorporation of carbon into the carbon monoxide and cyanide ligands of [NiFe]-hydrogenases has been investigated by using (13)C labelling in infrared studies of the Allochromatium vinosum enzyme and by (14)C labelling experiments with overproduced Hyp proteins from Escherichia coli. The results suggest that the biosynthetic routes of the carbon monoxide and cyanide ligands in [NiFe]-hydrogenases are different.

  8. Discovery of Dark pH-Dependent H(+) Migration in a [NiFe]-Hydrogenase and Its Mechanistic Relevance: Mobilizing the Hydrido Ligand of the Ni-C Intermediate.

    PubMed

    Murphy, Bonnie J; Hidalgo, Ricardo; Roessler, Maxie M; Evans, Rhiannon M; Ash, Philip A; Myers, William K; Vincent, Kylie A; Armstrong, Fraser A

    2015-07-01

    Despite extensive studies on [NiFe]-hydrogenases, the mechanism by which these enzymes produce and activate H2 so efficiently remains unclear. A well-known EPR-active state produced under H2 and known as Ni-C is assigned as a Ni(III)-Fe(II) species with a hydrido ligand in the bridging position between the two metals. It has long been known that low-temperature photolysis of Ni-C yields distinctive EPR-active states, collectively termed Ni-L, that are attributed to migration of the bridging-H species as a proton; however, Ni-L has mainly been regarded as an artifact with no mechanistic relevance. It is now demonstrated, based on EPR and infrared spectroscopic studies, that the Ni-C to Ni-L interconversion in Hydrogenase-1 (Hyd-1) from Escherichia coli is a pH-dependent process that proceeds readily in the dark-proton migration from Ni-C being favored as the pH is increased. The persistence of Ni-L in Hyd-1 must relate to unassigned differences in proton affinities of metal and adjacent amino acid sites, although the unusually high reduction potentials of the adjacent Fe-S centers in this O2-tolerant hydrogenase might also be a contributory factor, impeding elementary electron transfer off the [NiFe] site after proton departure. The results provide compelling evidence that Ni-L is a true, albeit elusive, catalytic intermediate of [NiFe]-hydrogenases.

  9. Nuclear resonance vibrational spectroscopy reveals the FeS cluster composition and active site vibrational properties of an O2-tolerant NAD+-reducing [NiFe] hydrogenase

    SciTech Connect

    Lauterbach, Lars; Wang, Hongxin; Horch, Marius; Gee, Leland B.; Yoda, Yoshitaka; Tanaka, Yoshihito; Zebger, Ingo; Lenz, Oliver; Cramer, Stephen P.

    2014-10-30

    Hydrogenases are complex metalloenzymes that catalyze the reversible splitting of molecular hydrogen into protons and electrons essentially without overpotential. The NAD+-reducing soluble hydrogenase (SH) from Ralstonia eutropha is capable of H2 conversion even in the presence of usually toxic dioxygen. The molecular details of the underlying reactions are largely unknown, mainly because of limited knowledge of the structure and function of the various metal cofactors present in the enzyme. Here, all iron-containing cofactors of the SH were investigated by 57Fe specific nuclear resonance vibrational spectroscopy (NRVS). Our data provide experimental evidence for one [2Fe2S] center and four [4Fe4S] clusters, which is consistent with the amino acid sequence composition. Only the [2Fe2S] cluster and one of the four [4Fe4S] clusters were reduced upon incubation of the SH with NADH. This finding explains the discrepancy between the large number of FeS clusters and the small amount of FeS cluster-related signals as detected by electron paramagnetic resonance spectroscopic analysis of several NAD+-reducing hydrogenases. For the first time, Fe–CO and Fe–CN modes derived from the [NiFe] active site could be distinguished by NRVS through selective 13C labeling of the CO ligand. This strategy also revealed the molecular coordinates that dominate the individual Fe–CO modes. The present approach explores the complex vibrational signature of the Fe–S clusters and the hydrogenase active site, thereby showing that NRVS represents a powerful tool for the elucidation of complex biocatalysts containing multiple cofactors.

  10. Microarray analysis of relative gene expression stability for selection of internal reference genes in the rhesus macaque brain

    PubMed Central

    2010-01-01

    Background Normalization of gene expression data refers to the comparison of expression values using reference standards that are consistent across all conditions of an experiment. In PCR studies, genes designated as "housekeeping genes" have been used as internal reference genes under the assumption that their expression is stable and independent of experimental conditions. However, verification of this assumption is rarely performed. Here we assess the use of gene microarray analysis to facilitate selection of internal reference sequences with higher expression stability across experimental conditions than can be expected using traditional selection methods. We recently demonstrated that relative gene expression from qRT-PCR data normalized using GAPDH, ALG9 and RPL13A expression values mirrored relative expression using quantile normalization in Robust Multichip Analysis (RMA) on the Affymetrix® GeneChip® rhesus Macaque Genome Array. Having shown that qRT-PCR and Affymetrix® GeneChip® data from the same hormone replacement therapy (HRT) study yielded concordant results, we used quantile-normalized gene microarray data to identify the most stably expressed among probe sets for prospective internal reference genes across three brain regions from the HRT study and an additional study of normally menstruating rhesus macaques (cycle study). Gene selection was limited to 575 previously published human "housekeeping" genes. Twelve animals were used per study, and three brain regions were analyzed from each animal. Gene expression stabilities were determined using geNorm, NormFinder and BestKeeper software packages. Results Sequences co-annotated for ribosomal protein S27a (RPS27A), and ubiquitin were among the most stably expressed under all conditions and selection criteria used for both studies. Higher annotation quality on the human GeneChip® facilitated more targeted analysis than could be accomplished using the rhesus GeneChip®. In the cycle study, multiple

  11. Impact of the chemicals, essential for the purification process of strict Fe-hydrogenase, on the corrosion of mild steel.

    PubMed

    Rouvre, Ingrid; Gauquelin, Charles; Meynial-Salles, Isabelle; Basseguy, Régine

    2016-06-01

    The influence of additional chemical molecules, necessary for the purification process of [Fe]-hydrogenase from Clostridium acetobutylicum, was studied on the anaerobic corrosion of mild steel. At the end of the purification process, the pure [Fe-Fe]-hydrogenase was recovered in a Tris-HCl medium containing three other chemicals at low concentration: DTT, dithionite and desthiobiotin. Firstly, mild steel coupons were exposed in parallel to a 0.1 M pH7 Tris-HCl medium with or without pure hydrogenase. The results showed that hydrogenase and the additional molecules were in competition, and the electrochemical response could not be attributed solely to hydrogenase. Then, solutions with additional chemicals of different compositions were studied electrochemically. DTT polluted the electrochemical signal by increasing the Eoc by 35 mV 24 h after the injection of 300 μL of control solutions with DTT, whereas it drastically decreased the corrosion rate by increasing the charge transfer resistance (Rct 10 times the initial value). Thus, DTT was shown to have a strong antagonistic effect on corrosion and was removed from the purification process. An optimal composition of the medium was selected (0.5 mM dithionite, 7.5 mM desthiobiotin) that simultaneously allowed a high activity of hydrogenase and a lower impact on the electrochemical response for corrosion tests.

  12. Identification of recurrence-related genes by integrating microRNA and gene expression profiling of gastric cancer.

    PubMed

    Yan, Zhi; Xiong, Yimin; Xu, Weitian; Li, Min; Cheng, Yi; Chen, Fang; Ding, Shifang; Xu, Hualin; Zheng, Guorong

    2012-12-01

    We previously analyzed the microRNA (miRNA) expression pattern in gastric cancer with and without recurrence and obtained 17 differentially expressed miRNAs with potential to predict recurrence risk for GC patients. In the present study, we aimed to investigate recurrence-related genes which may be regulated by the differentially expressed miRNAs identified in our prior research. Three different miRNA target gene databases (miRanda, TargetScan and PicTar) were used for searching the potential genes regulated by miRNAs. A combination was performed between miRNA target genes and recurrence-related gene expression profiling. Three bioinformatics algorithms (PAM, SVM and RF) were used to feature recurrence-related gene selection. In addition, we validated the expression levels of the genes in GC patients using real-time PCR. A total of 3,263 genes were identified as potential targets of 17 miRNAs. We identified 2,736 differential expressed genes using the SAM method based on 22K oligo microarray data which included 7 recurrence and 4 without recurrence GC samples. Combining the target genes regulated by miRNAs and the differentially expressed genes between recurrence and non-recurrence groups, we identified 228 differential genes for further study. Finally, we identified HNRPA0 and PRDM4 as risk biomarkers of GC patients, which were regulated by hsa-miR‑194 and hsa-miR-373, respectively. Our data indicated that HNRPA0 and PRDM4 may be involved in the recurrence process of GC and have potential to act as new prognostic biomarkers in predicting recurrence risk for gastric cancer patients.

  13. LGscore: A method to identify disease-related genes using biological literature and Google data.

    PubMed

    Kim, Jeongwoo; Kim, Hyunjin; Yoon, Youngmi; Park, Sanghyun

    2015-04-01

    Since the genome project in 1990s, a number of studies associated with genes have been conducted and researchers have confirmed that genes are involved in disease. For this reason, the identification of the relationships between diseases and genes is important in biology. We propose a method called LGscore, which identifies disease-related genes using Google data and literature data. To implement this method, first, we construct a disease-related gene network using text-mining results. We then extract gene-gene interactions based on co-occurrences in abstract data obtained from PubMed, and calculate the weights of edges in the gene network by means of Z-scoring. The weights contain two values: the frequency and the Google search results. The frequency value is extracted from literature data, and the Google search result is obtained using Google. We assign a score to each gene through a network analysis. We assume that genes with a large number of links and numerous Google search results and frequency values are more likely to be involved in disease. For validation, we investigated the top 20 inferred genes for five different diseases using answer sets. The answer sets comprised six databases that contain information on disease-gene relationships. We identified a significant number of disease-related genes as well as candidate genes for Alzheimer's disease, diabetes, colon cancer, lung cancer, and prostate cancer. Our method was up to 40% more accurate than existing methods.

  14. Meta-analysis of age-related gene expression profiles identifies common signatures of aging

    PubMed Central

    de Magalhães, João Pedro; Curado, João; Church, George M.

    2009-01-01

    Motivation: Numerous microarray studies of aging have been conducted, yet given the noisy nature of gene expression changes with age, elucidating the transcriptional features of aging and how these relate to physiological, biochemical and pathological changes remains a critical problem. Results: We performed a meta-analysis of age-related gene expression profiles using 27 datasets from mice, rats and humans. Our results reveal several common signatures of aging, including 56 genes consistently overexpressed with age, the most significant of which was APOD, and 17 genes underexpressed with age. We characterized the biological processes associated with these signatures and found that age-related gene expression changes most notably involve an overexpression of inflammation and immune response genes and of genes associated with the lysosome. An underexpression of collagen genes and of genes associated with energy metabolism, particularly mitochondrial genes, as well as alterations in the expression of genes related to apoptosis, cell cycle and cellular senescence biomarkers, were also observed. By employing a new method that emphasizes sensitivity, our work further reveals previously unknown transcriptional changes with age in many genes, processes and functions. We suggest these molecular signatures reflect a combination of degenerative processes but also transcriptional responses to the process of aging. Overall, our results help to understand how transcriptional changes relate to the process of aging and could serve as targets for future studies. Availability: http://genomics.senescence.info/uarrays/signatures.html Contact: jp@senescence.info Supplementary information: Supplementary data are available at Bioinformatics online. PMID:19189975

  15. The clustering of functionally related genes contributes to CNV-mediated disease

    PubMed Central

    Andrews, Tallulah; Honti, Frantisek; Pfundt, Rolph; de Leeuw, Nicole; Hehir-Kwa, Jayne; Vulto-van Silfhout, Anneke; de Vries, Bert; Webber, Caleb

    2015-01-01

    Clusters of functionally related genes can be disrupted by a single copy number variant (CNV). We demonstrate that the simultaneous disruption of multiple functionally related genes is a frequent and significant characteristic of de novo CNVs in patients with developmental disorders (P = 1 × 10−3). Using three different functional networks, we identified unexpectedly large numbers of functionally related genes within de novo CNVs from two large independent cohorts of individuals with developmental disorders. The presence of multiple functionally related genes was a significant predictor of a CNV's pathogenicity when compared to CNVs from apparently healthy individuals and a better predictor than the presence of known disease or haploinsufficient genes for larger CNVs. The functionally related genes found in the de novo CNVs belonged to 70% of all clusters of functionally related genes found across the genome. De novo CNVs were more likely to affect functional clusters and affect them to a greater extent than benign CNVs (P = 6 × 10−4). Furthermore, such clusters of functionally related genes are phenotypically informative: Different patients possessing CNVs that affect the same cluster of functionally related genes exhibit more similar phenotypes than expected (P < 0.05). The spanning of multiple functionally similar genes by single CNVs contributes substantially to how these variants exert their pathogenic effects. PMID:25887030

  16. Nuclear factor erythroid 2-related factor gene variants and susceptibility of arsenic-related skin lesions.

    PubMed

    Cordova, E J; Valenzuela, O L; Sánchez-Peña, L C; Escamilla-Guerrero, G; Hernández-Zavala, A; Orozco, L; Del Razo, L M

    2014-06-01

    Inorganic arsenic (iAs) is an important pollutant associated with various chronic-degenerative diseases. The cytoprotective protein nuclear factor erythroid 2-related factor (NRF2) has been proposed as an important responsive mechanism against iAs exposure. The aim of this study was to determine whether the risk of skin lesions in people exposed to iAs-contaminated water could be modified by the presence of single nucleotide polymorphisms in the NRF2 coding gene. We studied 117 individuals with long-term iAs exposure and 120 nonexposed individuals. Total As was determined in water, meanwhile iAs and its metabolites were measured in urine. The iAs-induced skin lesion status was evaluated by expert dermatologists. We sequenced the promoter region of NRF2 in a sample of 120 healthy donors. We found four polymorphisms previously reported and one novel polymorphism in the 5' regulatory region of the NRF2. In this study, we did not find allelic and genotype association of NRF2 polymorphisms with iAs-related skin lesion. However, the analysis of haplotypes composed by -653GA, and -617CA NRF2 single nucleotide polymorphisms showed a significant association with protection against skin lesions in the low-As exposure group. This is the first report studying the association between NRF2 polymorphisms and susceptibility of As-related skin lesions. Increasing the sample size will allow us to confirm this data. PMID:24107458

  17. Nuclear factor erythroid 2-related factor gene variants and susceptibility of arsenic-related skin lesions.

    PubMed

    Cordova, E J; Valenzuela, O L; Sánchez-Peña, L C; Escamilla-Guerrero, G; Hernández-Zavala, A; Orozco, L; Del Razo, L M

    2014-06-01

    Inorganic arsenic (iAs) is an important pollutant associated with various chronic-degenerative diseases. The cytoprotective protein nuclear factor erythroid 2-related factor (NRF2) has been proposed as an important responsive mechanism against iAs exposure. The aim of this study was to determine whether the risk of skin lesions in people exposed to iAs-contaminated water could be modified by the presence of single nucleotide polymorphisms in the NRF2 coding gene. We studied 117 individuals with long-term iAs exposure and 120 nonexposed individuals. Total As was determined in water, meanwhile iAs and its metabolites were measured in urine. The iAs-induced skin lesion status was evaluated by expert dermatologists. We sequenced the promoter region of NRF2 in a sample of 120 healthy donors. We found four polymorphisms previously reported and one novel polymorphism in the 5' regulatory region of the NRF2. In this study, we did not find allelic and genotype association of NRF2 polymorphisms with iAs-related skin lesion. However, the analysis of haplotypes composed by -653GA, and -617CA NRF2 single nucleotide polymorphisms showed a significant association with protection against skin lesions in the low-As exposure group. This is the first report studying the association between NRF2 polymorphisms and susceptibility of As-related skin lesions. Increasing the sample size will allow us to confirm this data.

  18. A strenuous experimental journey searching for spectroscopic evidence of a bridging nickel–iron–hydride in [NiFe] hydrogenase

    PubMed Central

    Wang, Hongxin; Yoda, Yoshitaka; Ogata, Hideaki; Tanaka, Yoshihito; Lubitz, Wolfgang

    2015-01-01

    Direct spectroscopic evidence for a hydride bridge in the Ni–R form of [NiFe] hydrogenase has been obtained using iron-specific nuclear resonance vibrational spectroscopy (NRVS). The Ni–H–Fe wag mode at 675 cm−1 is the first spectroscopic evidence for a bridging hydride in Ni–R as well as the first iron-hydride-related NRVS feature observed for a biological system. Although density function theory (DFT) calculation assisted the determination of the Ni–R structure, it did not predict the Ni–H–Fe wag mode at ∼675 cm−1 before NRVS. Instead, the observed Ni–H–Fe mode provided a critical reference for the DFT calculations. While the overall science about Ni–R is presented and discussed elsewhere, this article focuses on the long and strenuous experimental journey to search for and experimentally identify the Ni–H–Fe wag mode in a Ni–R sample. As a methodology, the results presented here will go beyond Ni–R and hydrogenase research and will also be of interest to other scientists who use synchrotron radiation for measuring dilute samples or weak spectroscopic features. PMID:26524296

  19. Adaptive eukaryote-to-eukaryote lateral gene transfer: stress-related genes of algal origin in the closest unicellular relatives of animals.

    PubMed

    Nedelcu, A M; Miles, I H; Fagir, A M; Karol, K

    2008-11-01

    In addition to mutation, gene duplication and recombination, the transfer of genetic material between unrelated species is now regarded as a potentially significant player in the shaping of extant genomes and the evolution and diversification of life. Although this is probably true for prokaryotes, the extent of such genetic exchanges in eukaryotes (especially eukaryote-to-eukaryote transfers) is more controversial and the selective advantage and evolutionary impact of such events are less documented. A laterally transferred gene could either be added to the gene complement of the recipient or replace the recipient's homologue; whereas gene replacements can be either adaptive or stochastic, gene additions are most likely adaptive. Here, we report the finding of four stress-related genes (two ascorbate peroxidase and two metacaspase genes) of algal origin in the closest unicellular relatives of animals, the choanoflagellates. At least three of these sequences represent additions to the choanoflagellate gene complement, which is consistent with these transfers being adaptive. We suggest that these laterally acquired sequences could have provided the primitive choanoflagellates with additional or more efficient means to cope with stress, especially in relation to adapting to freshwater environments and/or sessile or colonial lifestyles.

  20. Adaptive eukaryote-to-eukaryote lateral gene transfer: stress-related genes of algal origin in the closest unicellular relatives of animals.

    PubMed

    Nedelcu, A M; Miles, I H; Fagir, A M; Karol, K

    2008-11-01

    In addition to mutation, gene duplication and recombination, the transfer of genetic material between unrelated species is now regarded as a potentially significant player in the shaping of extant genomes and the evolution and diversification of life. Although this is probably true for prokaryotes, the extent of such genetic exchanges in eukaryotes (especially eukaryote-to-eukaryote transfers) is more controversial and the selective advantage and evolutionary impact of such events are less documented. A laterally transferred gene could either be added to the gene complement of the recipient or replace the recipient's homologue; whereas gene replacements can be either adaptive or stochastic, gene additions are most likely adaptive. Here, we report the finding of four stress-related genes (two ascorbate peroxidase and two metacaspase genes) of algal origin in the closest unicellular relatives of animals, the choanoflagellates. At least three of these sequences represent additions to the choanoflagellate gene complement, which is consistent with these transfers being adaptive. We suggest that these laterally acquired sequences could have provided the primitive choanoflagellates with additional or more efficient means to cope with stress, especially in relation to adapting to freshwater environments and/or sessile or colonial lifestyles. PMID:18717747

  1. Megakaryocyte- and megakaryocyte precursor–related gene therapies

    PubMed Central

    2016-01-01

    Hematopoietic stem cells (HSCs) can be safely collected from the body, genetically modified, and re-infused into a patient with the goal to express the transgene product for an individual’s lifetime. Hematologic defects that can be corrected with an allogeneic bone marrow transplant can theoretically also be treated with gene replacement therapy. Because some genetic disorders affect distinct cell lineages, researchers are utilizing HSC gene transfer techniques using lineage-specific endogenous gene promoters to confine transgene expression to individual cell types (eg, ITGA2B for inherited platelet defects). HSCs appear to be an ideal target for platelet gene therapy because they can differentiate into megakaryocytes which are capable of forming several thousand anucleate platelets that circulate within blood vessels to establish hemostasis by repairing vascular injury. Platelets play an essential role in other biological processes (immune response, angiogenesis) as well as diseased states (atherosclerosis, cancer, thrombosis). Thus, recent advances in genetic manipulation of megakaryocytes could lead to new and improved therapies for treating a variety of disorders. In summary, genetic manipulation of megakaryocytes has progressed to the point where clinically relevant strategies are being developed for human trials for genetic disorders affecting platelets. Nevertheless, challenges still need to be overcome to perfect this field; therefore, strategies to increase the safety and benefit of megakaryocyte gene therapy will be discussed. PMID:26787735

  2. Hydrogenase of the hyperthermophile Pyrococcus furiosus is an elemental sulfur reductase or sulfhydrogenase: Evidence for a sulfur-reducing hydrogenase ancestor

    SciTech Connect

    Ma, K.; Adams, M.W.W. ); Schicho, R.N. ); Kelly, R.M. )

    1993-06-01

    Microorganisms growing near and above 100[degrees]C have recently been discovered near shallow and deep sea hydrothermal vents. Most are obligately dependent upon the reduction of elemental sulfur (S[sup 0]) to hydrogen sulfide (H[sub 2]S) for optimal growth, even though S[sup 0] reduction readily occurs abiotically at their growth temperatures. The sulfur reductase activity of the anaerobic archaeon Pyrococcus furiosus, which grows optimally at 100[degrees]C by a metabolism that produces H[sub 2]S if S[sup 0] is present, was found in the cytoplasm. It was purified anaerobically and was shown to be identical to the hydrogenase that had been previously purified from this organism. Both S[sup 0] and polysulfide served as substrates for H[sub 2]S production, and the S[sub 0] reduction activity but not the H[sub 2]-oxidation activity was enhanced by the redox protein rubredoxin. The H[sub 2]-oxidizing and S[sup 0]-reduction activities of the enzyme also showed different responses to pH, temperature, and inhibitors. This bifunctional [open quotes]sulfhydrogenase[close quotes] enzyme can, therefore, dispose of the excess reductant generated during fermentation using either protons or polysulfides as the electron acceptor. In addition, purified hydrogenases from both hyperthermophilic and mesophilic representatives of the archaeal and bacterial domains were shown to reduce S[sup 0] to H[sub 2]S. It is suggested that the function of some form of ancestral hydrogenase was S[sup 0] reduction rather than, or in addition, to the reduction of protons. 33 refs., 4 figs., 2 tabs.

  3. Gene expression profile analysis of testis and ovary of oriental river prawn, Macrobrachium nipponense, reveals candidate reproduction-related genes.

    PubMed

    Qiao, H; Xiong, Y W; Jiang, S F; Fu, H T; Sun, S M; Jin, S B; Gong, Y S; Zhang, W Y

    2015-01-01

    This study utilized high-throughput RNA sequencing technology to identify reproduction- and development-related genes of Macrobrachium nipponense by analyzing gene expression profiles of testis and ovary. More than 20 million 1 x 51-bp reads were obtained by Illumina sequencing, generating more than 7.7 and 11.7 million clean reads in the testis and ovary library, respectively. As a result, 10,018 unitags were supposed to be differentially expressed genes (DEGs) between ovary and testis. Compared to the ovary library, 4563 (45.5%) of these DEGs exhibited at least 6-fold upregulated expression, while 5455 (54.5%) DEGs exhibited at least 2-fold downregulated expression in the testis. The Gene Ontology (GO) enrichment analysis showed that 113 GO terms had potential molecular functions in reproduction. The Kyoto Encyclopedia of Genes and Genomes results revealed that the most important pathways may be relevant to reproduction and included 7 pathways. Forty-two genes were identified as reproduction-, development-, and sex-related genes based on GO classification and sequence comparison with other publications, including male reproductive-related LIM protein, spermatogenesis-associated protein, gametocyte-specific factor 1, VASA-like protein, vitellogenin, sex-determining protein fem-1, and other potential candidates. These results will advance research in the field of molecular genetics in M. nipponense and offer a valuable resource for further research related to reproduction in crustaceans. PMID:25867350

  4. Gene expression profile analysis of testis and ovary of oriental river prawn, Macrobrachium nipponense, reveals candidate reproduction-related genes.

    PubMed

    Qiao, H; Xiong, Y W; Jiang, S F; Fu, H T; Sun, S M; Jin, S B; Gong, Y S; Zhang, W Y

    2015-03-20

    This study utilized high-throughput RNA sequencing technology to identify reproduction- and development-related genes of Macrobrachium nipponense by analyzing gene expression profiles of testis and ovary. More than 20 million 1 x 51-bp reads were obtained by Illumina sequencing, generating more than 7.7 and 11.7 million clean reads in the testis and ovary library, respectively. As a result, 10,018 unitags were supposed to be differentially expressed genes (DEGs) between ovary and testis. Compared to the ovary library, 4563 (45.5%) of these DEGs exhibited at least 6-fold upregulated expression, while 5455 (54.5%) DEGs exhibited at least 2-fold downregulated expression in the testis. The Gene Ontology (GO) enrichment analysis showed that 113 GO terms had potential molecular functions in reproduction. The Kyoto Encyclopedia of Genes and Genomes results revealed that the most important pathways may be relevant to reproduction and included 7 pathways. Forty-two genes were identified as reproduction-, development-, and sex-related genes based on GO classification and sequence comparison with other publications, including male reproductive-related LIM protein, spermatogenesis-associated protein, gametocyte-specific factor 1, VASA-like protein, vitellogenin, sex-determining protein fem-1, and other potential candidates. These results will advance research in the field of molecular genetics in M. nipponense and offer a valuable resource for further research related to reproduction in crustaceans.

  5. Characterization of rainbow trout (Oncorhynchus mykiss) spleen transcriptome and identification of immune-related genes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Resistance against specific diseases is affecting profitability in fish production systems including rainbow trout. Limited information is known about functions and mechanisms of the immune gene pathways in teleosts. Immunogenomics are powerful tools to determine immune-related genes/gene pathways a...

  6. Characterization and expression analysis of a Retinoblastoma-related gene from Chinese wild Vitis pseudoreticulata

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Retinoblastoma-related (RBR) genes, a conserved gene family in higher eukaryotes, plays an important role in cell differentiation, development and mammalian cell death in animals; however, little is known about its function in plants. In this study, an RBR gene was isolated from the Chinese wild gr...

  7. Purification and Characterization of [NiFe]-Hydrogenase of Shewanella oneidensis MR-1

    SciTech Connect

    Shi, Liang; Belchik, Sara M.; Plymale, Andrew E.; Heald, Steve M.; Dohnalkova, Alice; Sybirna, Kateryna; Bottin, Herve; Squier, Thomas C.; Zachara, John M.; Fredrickson, Jim K.

    2011-08-02

    The γ-proteobacterium Shewanella oneidensis MR-1 possesses a periplasmic [NiFe]-hydrogenase (MR-1 [NiFe]-H2ase) that was implicated in both H2 production and oxidation as well as technetium [Tc(VII)] reduction. To characterize the roles of MR-1 [NiFe]-H2ase in these proposed reactions, the genes encoding both subunits of MR-1 [NiFe]-H2ase were cloned into a protein expression vector. The resulting plasmid was transformed into a MR-1 mutant deficient in H2 formation. Expression of MR-1 [NiFe]-H2ase in trans restored the mutant’s ability to produce H2 at 37% of that for wild type. Following expression, MR-1 [NiFe]-H2ase was purified to near homogeneity. The purified MR-1 [NiFe]-H2ase could couple H2 oxidation to reduction of Tc(VII) and methyl viologen directly. Change of the buffers used affected MR-1 [NiFe]-H2ase-mediated Tc(VII) but not methyl viologen reductions. Under the conditions tested, Tc(VII) reduction was complete in Tris buffer but not in HEPES buffer. The reduced Tc(IV) was soluble in Tris buffer but insoluble in HEPES buffer. Transmission electron microscopy analysis revealed that Tc(IV) precipitates formed in HEPES buffer were packed with crystallites. Although X-ray absorption near-edge spectroscopy measurements confirmed that the reduction products found in both buffers were Tc(IV), extended X-ray adsorption fine-structure measurements revealed that these products were very different. While the product in Tris buffer could not be determined, the Tc(IV) product in HEPES buffer was very similar to Tc(IV)O2•nH2O. These results shows for the first time that MR-1 [NiFe]-H2ase is a bidirectional enzyme that catalyzes both H2 formation and oxidation as well as Tc(VII) reduction directly by coupling H2 oxidation.

  8. Activities of calcitonin gene-related peptide (CGRP) and related peptides at the CGRP receptor

    SciTech Connect

    Maton, P.N.; Pradhan, T.; Zhou, Z.C.; Gardner, J.D.; Jensen, R.T. )

    1990-05-01

    In guinea pig pancreatic acini rat calcitonin gene-related peptide (CGRP) increased amylase release 2-fold, salmon calcitonin had an efficacy of only 44% of that of CGRP and (Tyr0)CGRP(28-37) and human calcitonin had no actions. (Tyr0)CGRP(28-37), but not human calcitonin, antagonized the actions of CGRP in pancreatic acini with an IC50 of 3 microM. (Tyr0)CGRP(28-37) produced a parallel rightward shift in the dose-response curve for CGRP-stimulated amylase secretion. The inhibition was specific for CGRP and was reversible. Studies with 125I-CGRP demonstrated that CGRP, salmon calcitonin and (Tyr0)CGRP, but not human calcitonin, interacted with CGRP receptors on pancreatic acini. These results indicate that various CGRP-related peptides demonstrate different relationships between their abilities to occupy the CGRP receptor and to affect biologic activity, with CGRP itself being a full agonist, salmon calcitonin a partial agonist, (Tyr0)CGRP(28-37) a competitive antagonist, and human calcitonin having no actions.

  9. Artificial hydrogenases: biohybrid and supramolecular systems for catalytic hydrogen production or uptake.

    PubMed

    Caserta, Giorgio; Roy, Souvik; Atta, Mohamed; Artero, Vincent; Fontecave, Marc

    2015-04-01

    There is an urgent need for cheap, abundant and efficient catalysts as an alternative to platinum for hydrogen production and oxidation in (photo)electrolyzers and fuel cells. Hydrogenases are attractive solutions. These enzymes use exclusively nickel and iron in their active sites and function with high catalytic rates at the thermodynamic equilibrium. As an alternative, a number of biomimetic and bioinspired catalysts for H2 production and/or uptake, based on Ni, Fe and Co, have been developed and shown to display encouraging performances. In this review we discuss specifically recent approaches aiming at incorporating these compounds within oligomeric and polymeric hosts. The latter are most often biological compounds (peptides, proteins, polysaccharides, etc.) but we also discuss non-biological scaffolds (synthetic polymers, Metal-organic-Frameworks, etc.) which can provide the appropriate environment to tune the activity and stability of the synthetic catalysts. These supramolecular catalytic systems thus define a class of original compounds so-called artificial hydrogenases.

  10. Solution-phase photochemistry of a [FeFe]hydrogenase model compound: Evidence of photoinduced isomerisation

    SciTech Connect

    Kania, Rafal; Hunt, Neil T.; Frederix, Pim W. J. M.; Wright, Joseph A.; Pickett, Christopher J.; Ulijn, Rein V.

    2012-01-28

    The solution-phase photochemistry of the [FeFe] hydrogenase subsite model ({mu}-S(CH{sub 2}){sub 3}S)Fe{sub 2}(CO){sub 4}(PMe{sub 3}){sub 2} has been studied using ultrafast time-resolved infrared spectroscopy supported by density functional theory calculations. In three different solvents, n-heptane, methanol, and acetonitrile, relaxation of the tricarbonyl intermediate formed by UV photolysis of a carbonyl ligand leads to geminate recombination with a bias towards a thermodynamically less stable isomeric form, suggesting that facile interconversion of the ligand groups at the Fe center is possible in the unsaturated species. In a polar or hydrogen bonding solvent, this process competes with solvent substitution leading to the formation of stable solvent adduct species. The data provide further insight into the effect of incorporating non-carbonyl ligands on the dynamics and photochemistry of hydrogenase-derived biomimetic compounds.

  11. Solution-phase photochemistry of a [FeFe]hydrogenase model compound: evidence of photoinduced isomerisation.

    PubMed

    Kania, Rafal; Frederix, Pim W J M; Wright, Joseph A; Ulijn, Rein V; Pickett, Christopher J; Hunt, Neil T

    2012-01-28

    The solution-phase photochemistry of the [FeFe] hydrogenase subsite model (μ-S(CH(2))(3)S)Fe(2)(CO)(4)(PMe(3))(2) has been studied using ultrafast time-resolved infrared spectroscopy supported by density functional theory calculations. In three different solvents, n-heptane, methanol, and acetonitrile, relaxation of the tricarbonyl intermediate formed by UV photolysis of a carbonyl ligand leads to geminate recombination with a bias towards a thermodynamically less stable isomeric form, suggesting that facile interconversion of the ligand groups at the Fe center is possible in the unsaturated species. In a polar or hydrogen bonding solvent, this process competes with solvent substitution leading to the formation of stable solvent adduct species. The data provide further insight into the effect of incorporating non-carbonyl ligands on the dynamics and photochemistry of hydrogenase-derived biomimetic compounds.

  12. From hydrogenases to noble metal-free catalytic nanomaterials for H2 production and uptake.

    PubMed

    Le Goff, Alan; Artero, Vincent; Jousselme, Bruno; Tran, Phong Dinh; Guillet, Nicolas; Métayé, Romain; Fihri, Aziz; Palacin, Serge; Fontecave, Marc

    2009-12-01

    Interconversion of water and hydrogen in unitized regenerative fuel cells is a promising energy storage framework for smoothing out the temporal fluctuations of solar and wind power. However, replacement of presently available platinum catalysts by lower-cost and more abundant materials is a requisite for this technology to become economically viable. Here, we show that the covalent attachment of a nickel bisdiphosphine-based mimic of the active site of hydrogenase enzymes onto multiwalled carbon nanotubes results in a high-surface area cathode material with high catalytic activity under the strongly acidic conditions required in proton exchange membrane technology. Hydrogen evolves from aqueous sulfuric acid solution with very low overvoltages (20 millivolts), and the catalyst exhibits exceptional stability (more than 100,000 turnovers). The same catalyst is also very efficient for hydrogen oxidation in this environment, exhibiting current densities similar to those observed for hydrogenase-based materials.

  13. Electrochemical insights into the mechanism of NiFe membrane-bound hydrogenases

    PubMed Central

    Flanagan, Lindsey A.; Parkin, Alison

    2016-01-01

    Hydrogenases are enzymes of great biotechnological relevance because they catalyse the interconversion of H2, water (protons) and electricity using non-precious metal catalytic active sites. Electrochemical studies into the reactivity of NiFe membrane-bound hydrogenases (MBH) have provided a particularly detailed insight into the reactivity and mechanism of this group of enzymes. Significantly, the control centre for enabling O2 tolerance has been revealed as the electron-transfer relay of FeS clusters, rather than the NiFe bimetallic active site. The present review paper will discuss how electrochemistry results have complemented those obtained from structural and spectroscopic studies, to present a complete picture of our current understanding of NiFe MBH. PMID:26862221

  14. Hydrogenase Enzymes and Their Synthetic Models: The Role of Metal Hydrides.

    PubMed

    Schilter, David; Camara, James M; Huynh, Mioy T; Hammes-Schiffer, Sharon; Rauchfuss, Thomas B

    2016-08-10

    Hydrogenase enzymes efficiently process H2 and protons at organometallic FeFe, NiFe, or Fe active sites. Synthetic modeling of the many H2ase states has provided insight into H2ase structure and mechanism, as well as afforded catalysts for the H2 energy vector. Particularly important are hydride-bearing states, with synthetic hydride analogues now known for each hydrogenase class. These hydrides are typically prepared by protonation of low-valent cores. Examples of FeFe and NiFe hydrides derived from H2 have also been prepared. Such chemistry is more developed than mimicry of the redox-inactive monoFe enzyme, although functional models of the latter are now emerging. Advances in physical and theoretical characterization of H2ase enzymes and synthetic models have proven key to the study of hydrides in particular, and will guide modeling efforts toward more robust and active species optimized for practical applications. PMID:27353631

  15. A Hybrid Computational Method for the Discovery of Novel Reproduction-Related Genes

    PubMed Central

    Chen, Lei; Chu, Chen; Kong, Xiangyin; Huang, Guohua; Huang, Tao; Cai, Yu-Dong

    2015-01-01

    Uncovering the molecular mechanisms underlying reproduction is of great importance to infertility treatment and to the generation of healthy offspring. In this study, we discovered novel reproduction-related genes with a hybrid computational method, integrating three different types of method, which offered new clues for further reproduction research. This method was first executed on a weighted graph, constructed based on known protein-protein interactions, to search the shortest paths connecting any two known reproduction-related genes. Genes occurring in these paths were deemed to have a special relationship with reproduction. These newly discovered genes were filtered with a randomization test. Then, the remaining genes were further selected according to their associations with known reproduction-related genes measured by protein-protein interaction score and alignment score obtained by BLAST. The in-depth analysis of the high confidence novel reproduction genes revealed hidden mechanisms of reproduction and provided guidelines for further experimental validations. PMID:25768094

  16. A hybrid computational method for the discovery of novel reproduction-related genes.

    PubMed

    Chen, Lei; Chu, Chen; Kong, Xiangyin; Huang, Guohua; Huang, Tao; Cai, Yu-Dong

    2015-01-01

    Uncovering the molecular mechanisms underlying reproduction is of great importance to infertility treatment and to the generation of healthy offspring. In this study, we discovered novel reproduction-related genes with a hybrid computational method, integrating three different types of method, which offered new clues for further reproduction research. This method was first executed on a weighted graph, constructed based on known protein-protein interactions, to search the shortest paths connecting any two known reproduction-related genes. Genes occurring in these paths were deemed to have a special relationship with reproduction. These newly discovered genes were filtered with a randomization test. Then, the remaining genes were further selected according to their associations with known reproduction-related genes measured by protein-protein interaction score and alignment score obtained by BLAST. The in-depth analysis of the high confidence novel reproduction genes revealed hidden mechanisms of reproduction and provided guidelines for further experimental validations.

  17. Applying the Fisher score to identify Alzheimer's disease-related genes.

    PubMed

    Yang, J; Liu, Y L; Feng, C S; Zhu, G Q

    2016-01-01

    Biologists and scientists can use the data from Alzheimer's disease (AD) gene expression microarrays to mine AD disease-related genes. Because of disadvantages such as small sample sizes, high dimensionality, and a high level of noise, it is difficult to obtain accurate and meaningful biological information from gene expression profiles. In this paper, we present a novel approach for utilizing AD microarray data to identify the morbigenous genes. The Fisher score, a classical feature selection method, is utilized to evaluate the importance of each gene. Genes with a large between-classes variance and small within-class variance are selected as candidate morbigenous genes. The results using an AD dataset show that the proposed approach is effective for gene selection. Satisfactory accuracy can be achieved by using only a small number of selected genes. PMID:27420981

  18. Les Liaisons Dangereuses: Cancer-Related Genes and Neurodegenerative Diseases

    NASA Astrophysics Data System (ADS)

    Ghetti, Bernardino; Buonaguro, Franco M.

    2014-07-01

    The following sections are included: * INTRODUCTION * MUTATIONS IN THE CSF1R GENE ASSOCIATED WITH DIFFUSE LEUKOENCEPHALOPATHY WITH SPHEROIDS AND HUMAN CANCERS. * A SPECIAL LINK HAS BEEN SHOWN BETWEEN PTEN AND AD. * ACETYLCHOLINE DEFICIENCY AND PATHOGENESIS OF AD. * MIRNAS AND COMMON PATHWAYS IN CANCER AND NEURODEGENERATIVE DISEASE. * SUMMARY * REFERENCES

  19. A Systematic Investigation into Aging Related Genes in Brain and Their Relationship with Alzheimer's Disease.

    PubMed

    Meng, Guofeng; Zhong, Xiaoyan; Mei, Hongkang

    2016-01-01

    Aging, as a complex biological process, is accompanied by the accumulation of functional loses at different levels, which makes age to be the biggest risk factor to many neurological diseases. Even following decades of investigation, the process of aging is still far from being fully understood, especially at a systematic level. In this study, we identified aging related genes in brain by collecting the ones with sustained and consistent gene expression or DNA methylation changes in the aging process. Functional analysis with Gene Ontology to these genes suggested transcriptional regulators to be the most affected genes in the aging process. Transcription regulation analysis found some transcription factors, especially Specificity Protein 1 (SP1), to play important roles in regulating aging related gene expression. Module-based functional analysis indicated these genes to be associated with many well-known aging related pathways, supporting the validity of our approach to select aging related genes. Finally, we investigated the roles of aging related genes on Alzheimer's Disease (AD). We found that aging and AD related genes both involved some common pathways, which provided a possible explanation why aging made the brain more vulnerable to Alzheimer's Disease.

  20. A Systematic Investigation into Aging Related Genes in Brain and Their Relationship with Alzheimer's Disease.

    PubMed

    Meng, Guofeng; Zhong, Xiaoyan; Mei, Hongkang

    2016-01-01

    Aging, as a complex biological process, is accompanied by the accumulation of functional loses at different levels, which makes age to be the biggest risk factor to many neurological diseases. Even following decades of investigation, the process of aging is still far from being fully understood, especially at a systematic level. In this study, we identified aging related genes in brain by collecting the ones with sustained and consistent gene expression or DNA methylation changes in the aging process. Functional analysis with Gene Ontology to these genes suggested transcriptional regulators to be the most affected genes in the aging process. Transcription regulation analysis found some transcription factors, especially Specificity Protein 1 (SP1), to play important roles in regulating aging related gene expression. Module-based functional analysis indicated these genes to be associated with many well-known aging related pathways, supporting the validity of our approach to select aging related genes. Finally, we investigated the roles of aging related genes on Alzheimer's Disease (AD). We found that aging and AD related genes both involved some common pathways, which provided a possible explanation why aging made the brain more vulnerable to Alzheimer's Disease. PMID:26937969

  1. CoMAGC: a corpus with multi-faceted annotations of gene-cancer relations

    PubMed Central

    2013-01-01

    Background In order to access the large amount of information in biomedical literature about genes implicated in various cancers both efficiently and accurately, the aid of text mining (TM) systems is invaluable. Current TM systems do target either gene-cancer relations or biological processes involving genes and cancers, but the former type produces information not comprehensive enough to explain how a gene affects a cancer, and the latter does not provide a concise summary of gene-cancer relations. Results In this paper, we present a corpus for the development of TM systems that are specifically targeting gene-cancer relations but are still able to capture complex information in biomedical sentences. We describe CoMAGC, a corpus with multi-faceted annotations of gene-cancer relations. In CoMAGC, a piece of annotation is composed of four semantically orthogonal concepts that together express 1) how a gene changes, 2) how a cancer changes and 3) the causality between the gene and the cancer. The multi-faceted annotations are shown to have high inter-annotator agreement. In addition, we show that the annotations in CoMAGC allow us to infer the prospective roles of genes in cancers and to classify the genes into three classes according to the inferred roles. We encode the mapping between multi-faceted annotations and gene classes into 10 inference rules. The inference rules produce results with high accuracy as measured against human annotations. CoMAGC consists of 821 sentences on prostate, breast and ovarian cancers. Currently, we deal with changes in gene expression levels among other types of gene changes. The corpus is available at http://biopathway.org/CoMAGCunder the terms of the Creative Commons Attribution License ( http://creativecommons.org/licenses/by/2.0). Conclusions The corpus will be an important resource for the development of advanced TM systems on gene-cancer relations. PMID:24225062

  2. Hydrogens detected by subatomic resolution protein crystallography in a [NiFe] hydrogenase.

    PubMed

    Ogata, Hideaki; Nishikawa, Koji; Lubitz, Wolfgang

    2015-04-23

    The enzyme hydrogenase reversibly converts dihydrogen to protons and electrons at a metal catalyst. The location of the abundant hydrogens is of key importance for understanding structure and function of the protein. However, in protein X-ray crystallography the detection of hydrogen atoms is one of the major problems, since they display only weak contributions to diffraction and the quality of the single crystals is often insufficient to obtain sub-ångström resolution. Here we report the crystal structure of a standard [NiFe] hydrogenase (∼91.3 kDa molecular mass) at 0.89 Å resolution. The strictly anoxically isolated hydrogenase has been obtained in a specific spectroscopic state, the active reduced Ni-R (subform Ni-R1) state. The high resolution, proper refinement strategy and careful modelling allow the positioning of a large part of the hydrogen atoms in the structure. This has led to the direct detection of the products of the heterolytic splitting of dihydrogen into a hydride (H(-)) bridging the Ni and Fe and a proton (H(+)) attached to the sulphur of a cysteine ligand. The Ni-H(-) and Fe-H(-) bond lengths are 1.58 Å and 1.78Å, respectively. Furthermore, we can assign the Fe-CO and Fe-CN(-) ligands at the active site, and can obtain the hydrogen-bond networks and the preferred proton transfer pathway in the hydrogenase. Our results demonstrate the precise comprehensive information available from ultra-high-resolution structures of proteins as an alternative to neutron diffraction and other methods such as NMR structural analysis. PMID:25624102

  3. Optimized Expression and Purification for High-Activity Preparations of Algal [FeFe]-Hydrogenase

    SciTech Connect

    Yacoby, I.; Tegler, L. T.; Pochekailov, S.; Zhang, S.; King, P. W.

    2012-04-01

    Recombinant expression and purification of metallo-enzymes, including hydrogenases, at high-yields is challenging due to complex, and enzyme specific, post-translational maturation processes. Low fidelities of maturation result in preparations containing a significant fraction of inactive, apo-protein that are not suitable for biophysical or crystallographic studies. We describe the construction, overexpression and high-yield purification of a fusion protein consisting of the algal [2Fe2S]-ferredoxin PetF (Fd) and [FeFe]-hydrogenase HydA1. The maturation of Fd-HydA1 was optimized through improvements in culture conditions and media components used for expression. We also demonstrated that fusion of Fd to the N-terminus of HydA1, in comparison to the C-terminus, led to increased expression levels that were 4-fold higher. Together, these improvements led to enhanced HydA1 activity and improved yield after purification. The strong binding-affinity of Fd for DEAE allowed for two-step purification by ion exchange and StrepTactin affinity chromatography. In addition, the incorporation of a TEV protease site in the Fd-HydA1 linker allowed for the proteolytic removal of Fd after DEAE step, and purification of HydA1 alone by StrepTactin. In combination, this process resulted in HydA1 purification yields of 5 mg L{sup -1} of culture from E. coli with specific activities of 1000 U (U = 1 {micro}mol hydrogen evolved mg{sup -1} min{sup -1}). The [FeFe]-hydrogenases are highly efficient enzymes and their catalytic sites provide model structures for synthetic efforts to develop robust hydrogen activation catalysts. In order to characterize their structure-function properties in greater detail, and to use hydrogenases for biotechnological applications, reliable methods for rapid, high-yield expression and purification are required.

  4. Symbiosis-related pea genes modulate fungal and plant gene expression during the arbuscule stage of mycorrhiza with Glomus intraradices.

    PubMed

    Kuznetsova, Elena; Seddas-Dozolme, Pascale M A; Arnould, Christine; Tollot, Marie; van Tuinen, Diederik; Borisov, Alexey; Gianinazzi, Silvio; Gianinazzi-Pearson, Vivienne

    2010-08-01

    The arbuscular mycorrhiza association results from a successful interaction between genomes of the plant and fungal symbiotic partners. In this study, we analyzed the effect of inactivation of late-stage symbiosis-related pea genes on symbiosis-associated fungal and plant molecular responses in order to gain insight into their role in the functional mycorrhizal association. The expression of a subset of ten fungal and eight plant genes, previously reported to be activated during mycorrhiza development, was compared in Glomus intraradices-inoculated wild-type and isogenic genotypes of pea mutated for the PsSym36, PsSym33, and PsSym40 genes where arbuscule formation is inhibited or fungal turnover modulated, respectively. Microdissection was used to corroborate arbuscule-related fungal gene expression. Molecular responses varied between pea genotypes and with fungal development. Most of the fungal genes were downregulated when arbuscule formation was defective, and several were upregulated with more rapid fungal development. Some of the plant genes were also affected by inactivation of the PsSym36, PsSym33, and PsSym40 loci, but in a more time-dependent way during root colonization by G. intraradices. Results indicate a role of the late-stage symbiosis-related pea genes not only in mycorrhiza development but also in the symbiotic functioning of arbuscule-containing cells.

  5. The effect of temperature and pH gradients on Lactobacillus rhamnosus gene expression of stress-related genes.

    PubMed

    Wallenius, Janne; Uuksulainen, Tuomas; Salonen, Kalle; Rautio, Jari; Eerikäinen, Tero

    2011-11-01

    In this study, Lactobacillus rhamnosus, a renowned probiotic, was cultivated in fluctuating environment. Base gradients caused by a pH control in an industrial process and temperature gradients caused by uneven heating were simulated with a scale-down method. A pH gradient was created in a plug flow reactor (PFR). Expression of pH stress-related genes (atpA, aldB, cfa, groEL, hrcA and pstS) were studied as a relative gene expression study using ldhD as a reference gene. Expression measurements were carried out with the TRAC method. The responses of groEL, hrcA and atpA genes to temperature and pH changes were observed. The expression of phosphate uptake system-related pstS gene was induced almost linearly in the chemostat cultivation experiments when the base gradient in the PFR was increased. Correlations between the results from gene expression studies and freeze stability or acid stress survival were studied. However, by measuring the expression of these genes, we were not able to predict eventual freeze stability or survival from the acid stress test.

  6. Selection of Reference Genes for Gene Expression Studies related to lung injury in a preterm lamb model.

    PubMed

    Pereira-Fantini, Prue M; Rajapaksa, Anushi E; Oakley, Regina; Tingay, David G

    2016-05-23

    Preterm newborns often require invasive support, however even brief periods of supported ventilation applied inappropriately to the lung can cause injury. Real-time quantitative reverse transcriptase-PCR (qPCR) has been extensively employed in studies of ventilation-induced lung injury with the reference gene 18S ribosomal RNA (18S RNA) most commonly employed as the internal control reference gene. Whilst the results of these studies depend on the stability of the reference gene employed, the use of 18S RNA has not been validated. In this study the expression profile of five candidate reference genes (18S RNA, ACTB, GAPDH, TOP1 and RPS29) in two geographical locations, was evaluated by dedicated algorithms, including geNorm, Normfinder, Bestkeeper and ΔCt method and the overall stability of these candidate genes determined (RefFinder). Secondary studies examined the influence of reference gene choice on the relative expression of two well-validated lung injury markers; EGR1 and IL1B. In the setting of the preterm lamb model of lung injury, RPS29 reference gene expression was influenced by tissue location; however we determined that individual ventilation strategies influence reference gene stability. Whilst 18S RNA is the most commonly employed reference gene in preterm lamb lung studies, our results suggest that GAPDH is a more suitable candidate.

  7. Age-related changes in relative expression stability of commonly used housekeeping genes in selected porcine tissues

    PubMed Central

    2011-01-01

    Background Gene expression analysis using real-time RT-PCR (qRT-PCR) is increasingly important in biological research due to the high-throughput and accuracy of qRT-PCR. For accurate and reliable gene expression analysis, normalization of gene expression data against housekeeping genes or internal control genes is required. The stability of reference genes has a tremendous effect on the results of relative quantification of gene expression by qRT-PCR. The expression stability of reference genes could vary according to tissues, age of individuals and experimental conditions. In the pig however, very little information is available on the expression stability of reference genes. The aim of this research was therefore to develop a new set of reference genes which can be used for normalization of mRNA expression data of genes expressed in varieties of porcine tissues at different ages. Results The mRNA expression stability of nine commonly used reference genes (B2M, BLM, GAPDH, HPRT1, PPIA, RPL4, SDHA, TBP and YWHAZ) was determined in varieties of tissues collected from newborn, young and adult pigs. geNorm, NormFinder and BestKeeper software were used to rank the genes according to their stability. geNorm software revealed that RPL4, PPIA and YWHAZ showed high stability in newborn and adult pigs, while B2M, YWHAZ and SDHA showed high stability in young pigs. In all cases, GAPDH showed the least stability in geNorm. NormFinder revealed that TBP was the most stable gene in newborn and young pigs, while PPIA was most stable in adult pigs. Moreover, geNorm software suggested that the geometric mean of three most stable gene would be the suitable combination for accurate normalization of gene expression study. Conclusions Although, there was discrepancy in the ranking order of reference genes obtained by different analysing software methods, the geometric mean of the RPL4, PPIA and YWHAZ seems to be the most appropriate combination of housekeeping genes for accurate

  8. Ventromedial hypothalamic lesions change the expression of cell proliferation-related genes and morphology-related genes in rat pancreatic islets

    PubMed Central

    Kiba, Takayoshi; Ishigaki, Yasuhito

    2014-01-01

    Studies in normal rats and ob/ob mice indicated that islet neogenesis does not occur in the intact rodent pancreas. We previously reported that ventromedial hypothalamic (VMH) lesions stimulated cell proliferation of rat pancreatic islet B and acinar cells primarily through a cholinergic receptor mechanism and examined how gene families involved in cell proliferation in total pancreatic tissue are regulated after VMH lesions formation. This study examined how gene families involved in cell proliferation in pancreatic islets alone are regulated after VMH lesions formation. Pancreatic islet RNA was extracted, and differences in gene expression profiles between rats at day 3 after VMH lesioning and sham-VMH-lesioned rats were investigated using DNA microarray and real-time polymerase chain reaction. VMH lesions regulated genes that were involved in functions related to cell cycle and differentiation, growth, binding, apoptosis and morphology in pancreas islets. Real-time polymerase chain reaction also confirmed that gene expression of polo-like kinase 1 (Plk1) and topoisomerase (DNA) II α 170 kDa (Top2a), and stanniocalcin 1 (Stc1) were upregulated at day 3 after the VMH lesions. Ventromedial hypothalamic lesions may change the expression of cell proliferation-related genes and morphology-related genes in rat pancreatic islets. PMID:25658146

  9. Transcriptome-Wide Differential Gene Expression in Bicyclus anynana Butterflies: Female Vision-Related Genes Are More Plastic.

    PubMed

    Macias-Muñoz, Aide; Smith, Gilbert; Monteiro, Antónia; Briscoe, Adriana D

    2016-01-01

    Vision is energetically costly to maintain. Consequently, over time many cave-adapted species downregulate the expression of vision genes or even lose their eyes and associated eye genes entirely. Alternatively, organisms that live in fluctuating environments, with different requirements for vision at different times, may evolve phenotypic plasticity for expression of vision genes. Here, we use a global transcriptomic and candidate gene approach to compare gene expression in the heads of a polyphenic butterfly. Bicyclus anynana have two seasonal forms that display sexual dimorphism and plasticity in eye morphology, and female-specific plasticity in opsin gene expression. Nonchoosy dry season females downregulate opsin expression, consistent with the high physiological cost of vision. To identify other genes associated with sexually dimorphic and seasonally plastic differences in vision, we analyzed RNA-sequencing data from whole head tissues. We identified two eye development genes (klarsicht and warts homologs) and an eye pigment biosynthesis gene (henna) differentially expressed between seasonal forms. By comparing sex-specific expression across seasonal forms, we found that klarsicht, warts, henna, and another eye development gene (domeless) were plastic in a female-specific manner. In a male-only analysis, white (w) was differentially expressed between seasonal forms. Reverse transcription polymerase chain reaction confirmed that warts and white are expressed in eyes only, whereas klarsicht, henna and domeless are expressed in both eyes and brain. We find that differential expression of eye development and eye pigment genes is associated with divergent eye phenotypes in B. anynana seasonal forms, and that there is a larger effect of season on female vision-related genes.

  10. Laughter up-regulates the genes related to NK cell activity in diabetes.

    PubMed

    Hayashi, Takashi; Tsujii, Satoru; Iburi, Tadao; Tamanaha, Tamiko; Yamagami, Keiko; Ishibashi, Rieko; Hori, Miyo; Sakamoto, Shigeko; Ishii, Hitoshi; Murakami, Kazuo

    2007-12-01

    To elucidate the sustainable effects of laughter on gene expression, we recruited type 2 diabetic patients who were in-patient for receiving self-management education and examined time-dependent regulation for gene expression by laughter. Two-day experiment was performed. On one day, the patients watched comic video and laughed together with hospital staffs. On the other day, they participated in an inpatient diabetes educational program. Blood samples were collected before and 1.5, 4 h after watching comic video or spending lecture time, and changes in gene expression were comprehensively analyzed by microarray technique. Of the 41,000 genes analyzed, the laughter relatively up-regulated 39 genes, among which, 27 genes were relatively increased in the expression for all the observation period after watching comic video. By functional classification of these genes, 14 genes were found to be related to natural killer cell activity. No genes were included that are directly involved in blood glucose regulation, though successive suppression of postprandial blood glucose levels was observed. These results suggest that the laughter influences the expression of many genes classified into immune responses, and may contribute to amelioration of postprandial blood glucose elevation through a modulation of NK cell activity caused by up-regulation of relating genes.

  11. Hydrogenase-independent uptake and metabolism of electrons by the archaeon Methanococcus maripaludis.

    PubMed

    Lohner, Svenja T; Deutzmann, Jörg S; Logan, Bruce E; Leigh, John; Spormann, Alfred M

    2014-08-01

    Direct, shuttle-free uptake of extracellular, cathode-derived electrons has been postulated as a novel mechanism of electron metabolism in some prokaryotes that may also be involved in syntrophic electron transport between two microorganisms. Experimental proof for direct uptake of cathodic electrons has been mostly indirect and has been based on the absence of detectable concentrations of molecular hydrogen. However, hydrogen can be formed as a transient intermediate abiotically at low cathodic potentials (<-414 mV) under conditions of electromethanogenesis. Here we provide genetic evidence for hydrogen-independent uptake of extracellular electrons. Methane formation from cathodic electrons was observed in a wild-type strain of the methanogenic archaeon Methanococcus maripaludis as well as in a hydrogenase-deletion mutant lacking all catabolic hydrogenases, indicating the presence of a hydrogenase-independent mechanism of electron catabolism. In addition, we discovered a new route for hydrogen or formate production from cathodic electrons: Upon chemical inhibition of methanogenesis with 2-bromo-ethane sulfonate, hydrogen or formate accumulated in the bioelectrochemical cells instead of methane. These results have implications for our understanding on the diversity of microbial electron uptake and metabolism.

  12. Atomic Resolution Modeling of the Ferredoxin:[FeFe] Hydrogenase Complex from Chlamydomonas reinhardtii

    SciTech Connect

    Chang, C. H.; King, P. W.; Ghirardi, M. L.; Kim, K.

    2007-11-01

    The [FeFe] hydrogenases HydA1 and HydA2 in the green alga Chlamydomonas reinhardtii catalyze the final reaction in a remarkable metabolic pathway allowing this photosynthetic organism to produce H2 from water in the chloroplast. A [2Fe-2S] ferredoxin is a critical branch point in electron flow from Photosystem I toward a variety of metabolic fates, including proton reduction by hydrogenases. To better understand the binding determinants involved in ferredoxin:hydrogenase interactions, we have modeled Chlamydomonas PetF1 and HydA2 based on amino-acid sequence homology, and produced two promising electron-transfer model complexes by computational docking. To characterize these models, quantitative free energy calculations at atomic resolution were carried out, and detailed analysis of the interprotein interactions undertaken. The protein complex model we propose for ferredoxin:HydA2 interaction is energetically favored over the alternative candidate by 20kcal/mol. This proposed model of the electron-transfer complex between PetF1 and HydA2 permits a more detailed view of the molecular events leading up to H2 evolution, and suggests potential mutagenic strategies to modulate electron flow to HydA2.

  13. Enzymatic catalysis in organic solvents: Polyethylene glycol modified hydrogenase retains sulfhydrogenase activity in toluene

    SciTech Connect

    Woodward, C.A.; Kaufman, E.N.

    1996-11-05

    Naturally occurring enzymes may be modified by covalently attaching hydrophobic groups that render the enzyme soluble and active in organic solvents, and have the potential to greatly expand applications of enzymatic catalysis. The reduction of elemental sulfur to hydrogen sulfide by a hydrogenase isolated from Pyrococcus furiosus has been investigated as a model system for organic biocatalysis. While the native hydrogenase catalyzed the reduction of sulfur to H{sub 2}S in aqueous solution, no activity was observed when the aqueous solvent was replaced with anhydrous toluene. Hydrogenase modified with PEG p-nitrophenyl carbonate demonstrated its native biocatalytic ability in toluene when the reducing dye, benzyl viologen, was also present. Neither benzyl viologen or PEG p-nitrophenyl carbonate alone demonstrated reducing capability. PEG modified cellulase and benzyl viologen were also incapable of reducing sulfur to H{sub 2}S, indicating that the enzyme itself, and not the modification procedure, is responsible for the conversion in the nonpolar organic solvent. Sulfide production in toluene was tenfold higher than that produced in an aqueous system with equal enzyme activity, demonstrating the advantages of organic biocatalysis. Applications of bioprocessing in nonaqueous media are expected to provide significant advances in the areas of fossil fuels, renewable feedstocks, organic synthesis, and environmental control technology.

  14. [FeFe]-hydrogenase oxygen inactivation is initiated at the H cluster 2Fe subcluster.

    PubMed

    Swanson, Kevin D; Ratzloff, Michael W; Mulder, David W; Artz, Jacob H; Ghose, Shourjo; Hoffman, Andrew; White, Spencer; Zadvornyy, Oleg A; Broderick, Joan B; Bothner, Brian; King, Paul W; Peters, John W

    2015-02-11

    The [FeFe]-hydrogenase catalytic site H cluster is a complex iron sulfur cofactor that is sensitive to oxygen (O2). The O2 sensitivity is a significant barrier for production of hydrogen as an energy source in water-splitting, oxygenic systems. Oxygen reacts directly with the H cluster, which results in rapid enzyme inactivation and eventual degradation. To investigate the progression of O2-dependent [FeFe]-hydrogenase inactivation and the process of H cluster degradation, the highly O2-sensitive [FeFe]-hydrogenase HydA1 from the green algae Chlamydomonas reinhardtii was exposed to defined concentrations of O2 while monitoring the loss of activity and accompanying changes in H cluster spectroscopic properties. The results indicate that H cluster degradation proceeds through a series of reactions, the extent of which depend on the initial enzyme reduction/oxidation state. The degradation process begins with O2 interacting and reacting with the 2Fe subcluster, leading to degradation of the 2Fe subcluster and leaving an inactive [4Fe-4S] subcluster state. This final inactive degradation product could be reactivated in vitro by incubation with 2Fe subcluster maturation machinery, specifically HydF(EG), which was observed by recovery of enzyme activity.

  15. Cyanobacterial hydrogenases and hydrogen metabolism revisited: recent progress and future prospects.

    PubMed

    Khanna, Namita; Lindblad, Peter

    2015-05-08

    Cyanobacteria have garnered interest as potential cell factories for hydrogen production. In conjunction with photosynthesis, these organisms can utilize inexpensive inorganic substrates and solar energy for simultaneous biosynthesis and hydrogen evolution. However, the hydrogen yield associated with these organisms remains far too low to compete with the existing chemical processes. Our limited understanding of the cellular hydrogen production pathway is a primary setback in the potential scale-up of this process. In this regard, the present review discusses the recent insight around ferredoxin/flavodoxin as the likely electron donor to the bidirectional Hox hydrogenase instead of the generally accepted NAD(P)H. This may have far reaching implications in powering solar driven hydrogen production. However, it is evident that a successful hydrogen-producing candidate would likely integrate enzymatic traits from different species. Engineering the [NiFe] hydrogenases for optimal catalytic efficiency or expression of a high turnover [FeFe] hydrogenase in these photo-autotrophs may facilitate the development of strains to reach target levels of biohydrogen production in cyanobacteria. The fundamental advancements achieved in these fields are also summarized in this review.

  16. Proton-coupled electron transfer dynamics in the catalytic mechanism of a [NiFe]-hydrogenase.

    PubMed

    Greene, Brandon L; Wu, Chang-Hao; McTernan, Patrick M; Adams, Michael W W; Dyer, R Brian

    2015-04-01

    The movement of protons and electrons is common to the synthesis of all chemical fuels such as H2. Hydrogenases, which catalyze the reversible reduction of protons, necessitate transport and reactivity between protons and electrons, but a detailed mechanism has thus far been elusive. Here, we use a phototriggered chemical potential jump method to rapidly initiate the proton reduction activity of a [NiFe] hydrogenase. Coupling the photochemical initiation approach to nanosecond transient infrared and visible absorbance spectroscopy afforded direct observation of interfacial electron transfer and active site chemistry. Tuning of intramolecular proton transport by pH and isotopic substitution revealed distinct concerted and stepwise proton-coupled electron transfer mechanisms in catalysis. The observed heterogeneity in the two sequential proton-associated reduction processes suggests a highly engineered protein environment modulating catalysis and implicates three new reaction intermediates; Nia-I, Nia-D, and Nia-SR(-). The results establish an elementary mechanistic understanding of catalysis in a [NiFe] hydrogenase with implications in enzymatic proton-coupled electron transfer and biomimetic catalyst design.

  17. Force Field Development and Molecular Dynamics of [NiFe] Hydrogenase

    SciTech Connect

    Smith, Dayle MA; Xiong, Yijia; Straatsma, TP; Rosso, Kevin M.; Squier, Thomas C.

    2012-05-09

    Classical molecular force-field parameters describing the structure and motion of metal clusters in [NiFe] hydrogenase enzymes can be used to compare the dynamics and thermodynamics of [NiFe] under different oxidation, protonation, and ligation circumstances. Using density functional theory (DFT) calculations of small model clusters representative of the active site and the proximal, medial, and distal Fe/S metal centers and their attached protein side chains, we have calculated classical force-field parameters for [NiFe] in reduced and oxidized states, including internal coordinates, force constants, and atom-centered charges. Derived force constants revealed that cysteinate ligands bound to the metal ions are more flexible in the Ni-B active site, which has a bridging hydroxide ligand, than in the Ni-C active site, which has a bridging hydride. Ten nanosecond all-atom, explicit-solvent MD simulations of [NiFe] hydrogenase in oxidized and reduced catalytic states established the stability of the derived force-field parameters in terms of C{alpha} and metal cluster fluctuations. Average active site structures from the protein MD simulations are consistent with [NiFe] structures from the Protein Data Bank, suggesting that the derived force-field parameters are transferrable to other hydrogenases beyond the structure used for testing. A comparison of experimental H{sub 2}-production rates demonstrated a relationship between cysteinate side chain rotation and activity, justifying the use of a fully dynamic model of [NiFe] metal cluster motion.

  18. Cyanobacterial Hydrogenases and Hydrogen Metabolism Revisited: Recent Progress and Future Prospects

    PubMed Central

    Khanna, Namita; Lindblad, Peter

    2015-01-01

    Cyanobacteria have garnered interest as potential cell factories for hydrogen production. In conjunction with photosynthesis, these organisms can utilize inexpensive inorganic substrates and solar energy for simultaneous biosynthesis and hydrogen evolution. However, the hydrogen yield associated with these organisms remains far too low to compete with the existing chemical processes. Our limited understanding of the cellular hydrogen production pathway is a primary setback in the potential scale-up of this process. In this regard, the present review discusses the recent insight around ferredoxin/flavodoxin as the likely electron donor to the bidirectional Hox hydrogenase instead of the generally accepted NAD(P)H. This may have far reaching implications in powering solar driven hydrogen production. However, it is evident that a successful hydrogen-producing candidate would likely integrate enzymatic traits from different species. Engineering the [NiFe] hydrogenases for optimal catalytic efficiency or expression of a high turnover [FeFe] hydrogenase in these photo-autotrophs may facilitate the development of strains to reach target levels of biohydrogen production in cyanobacteria. The fundamental advancements achieved in these fields are also summarized in this review. PMID:26006225

  19. Hydrogenase-independent uptake and metabolism of electrons by the archaeon Methanococcus maripaludis

    PubMed Central

    Lohner, Svenja T; Deutzmann, Jörg S; Logan, Bruce E; Leigh, John; Spormann, Alfred M

    2014-01-01

    Direct, shuttle-free uptake of extracellular, cathode-derived electrons has been postulated as a novel mechanism of electron metabolism in some prokaryotes that may also be involved in syntrophic electron transport between two microorganisms. Experimental proof for direct uptake of cathodic electrons has been mostly indirect and has been based on the absence of detectable concentrations of molecular hydrogen. However, hydrogen can be formed as a transient intermediate abiotically at low cathodic potentials (<−414 mV) under conditions of electromethanogenesis. Here we provide genetic evidence for hydrogen-independent uptake of extracellular electrons. Methane formation from cathodic electrons was observed in a wild-type strain of the methanogenic archaeon Methanococcus maripaludis as well as in a hydrogenase-deletion mutant lacking all catabolic hydrogenases, indicating the presence of a hydrogenase-independent mechanism of electron catabolism. In addition, we discovered a new route for hydrogen or formate production from cathodic electrons: Upon chemical inhibition of methanogenesis with 2-bromo-ethane sulfonate, hydrogen or formate accumulated in the bioelectrochemical cells instead of methane. These results have implications for our understanding on the diversity of microbial electron uptake and metabolism. PMID:24844759

  20. Proton Reduction Using a Hydrogenase-Modified Nanoporous Black Silicon Photoelectrode.

    PubMed

    Zhao, Yixin; Anderson, Nicholas C; Ratzloff, Michael W; Mulder, David W; Zhu, Kai; Turner, John A; Neale, Nathan R; King, Paul W; Branz, Howard M

    2016-06-15

    Metalloenzymes featuring earth-abundant metal-based cores exhibit rates for catalytic processes such as hydrogen evolution comparable to those of noble metals. Realizing these superb catalytic properties in artificial systems is challenging owing to the difficulty of effectively interfacing metalloenzymes with an electrode surface in a manner that supports efficient charge-transfer. Here, we demonstrate that a nanoporous "black" silicon (b-Si) photocathode provides a unique interface for binding an adsorbed [FeFe]-hydrogenase enzyme ([FeFe]-H2ase). The resulting [FeFe]-H2ase/b-Si photoelectrode displays a 280 mV more positive onset potential for hydrogen generation than bare b-Si without hydrogenase, similar to that observed for a b-Si/Pt photoelectrode at the same light intensity. Additionally, we show that this H2ase/b-Si electrode exhibits a turnover frequency of ≥1300 s(-1) and a turnover number above 10(7) and sustains current densities of at least 1 mA/cm(2) based on the actual surface area of the electrode (not the smaller projected geometric area), orders of magnitude greater than that observed for previous enzyme-catalyzed electrodes. While the long-term stability of hydrogenase on the b-Si surface remains too low for practical applications, this work extends the proof-of-concept that biologically derived metalloenzymes can be interfaced with inorganic substrates to support technologically relevant current densities. PMID:27219350

  1. [FeFe]-hydrogenase oxygen inactivation is initiated at the H cluster 2Fe subcluster.

    PubMed

    Swanson, Kevin D; Ratzloff, Michael W; Mulder, David W; Artz, Jacob H; Ghose, Shourjo; Hoffman, Andrew; White, Spencer; Zadvornyy, Oleg A; Broderick, Joan B; Bothner, Brian; King, Paul W; Peters, John W

    2015-02-11

    The [FeFe]-hydrogenase catalytic site H cluster is a complex iron sulfur cofactor that is sensitive to oxygen (O2). The O2 sensitivity is a significant barrier for production of hydrogen as an energy source in water-splitting, oxygenic systems. Oxygen reacts directly with the H cluster, which results in rapid enzyme inactivation and eventual degradation. To investigate the progression of O2-dependent [FeFe]-hydrogenase inactivation and the process of H cluster degradation, the highly O2-sensitive [FeFe]-hydrogenase HydA1 from the green algae Chlamydomonas reinhardtii was exposed to defined concentrations of O2 while monitoring the loss of activity and accompanying changes in H cluster spectroscopic properties. The results indicate that H cluster degradation proceeds through a series of reactions, the extent of which depend on the initial enzyme reduction/oxidation state. The degradation process begins with O2 interacting and reacting with the 2Fe subcluster, leading to degradation of the 2Fe subcluster and leaving an inactive [4Fe-4S] subcluster state. This final inactive degradation product could be reactivated in vitro by incubation with 2Fe subcluster maturation machinery, specifically HydF(EG), which was observed by recovery of enzyme activity. PMID:25579778

  2. Covalent attachment of FeFe hydrogenases to carbon electrodes for direct electron transfer.

    PubMed

    Baffert, Carole; Sybirna, Kateryna; Ezanno, Pierre; Lautier, Thomas; Hajj, Viviane; Meynial-Salles, Isabelle; Soucaille, Philippe; Bottin, Hervé; Léger, Christophe

    2012-09-18

    Direct electron transfer between enzymes and electrodes is now commonly achieved, but obtaining protein films that are very stable may be challenging. This is particularly crucial in the case of hydrogenases, the enzymes that catalyze the biological conversion between dihydrogen and protons, because the instability of the hydrogenase films may prevent the use of these enzymes as electrocatalysts of H(2) oxidation and production in biofuel cells and photoelectrochemical cells. Here we show that two different FeFe hydrogenases (from Chamydomonas reinhardtii and Clostridium acetobutylicum) can be covalently attached to functionalized pyrolytic graphite electrodes using peptidic coupling. In both cases, a surface patch of lysine residues makes it possible to favor an orientation that is efficient for fast, direct electron transfer. High hydrogen-oxidation current densities are maintained for up to one week, the only limitation being the intrinsic stability of the enzyme. We also show that covalent attachment has no effect on the catalytic properties of the enzyme, which means that this strategy can also used be for electrochemical studies of the catalytic mechanism. PMID:22891965

  3. Synthesis of the H-Cluster Framework of Iron-Only Hydrogenase

    SciTech Connect

    Tard, Cedric; Liu, Xiaohong; Ibrahim, S K.; Mauizio, Bruschi; De Gioia, Luca; Davies, Sian; Yang, Xin; Wang, Lai S.; Sawers, G; Pickett, Chris J.

    2005-02-10

    The reversible reduction of protons to dihydrogen is deceptively the simplest of reactions but one which requires multi-step catalysis to proceed at practical rates. How the metal-sulfur of the hydrogenases catalyse this interconversion has been the subject has been the subject of intensive structural, spectroscopic and mechanistic studies of the enzymes, of synthetic assemblies and of in silico models. Beyond the intrinsic desire to understand how metallo-sulfur clusters in biology catalyses a range of difficult chemistry, including nitrogen fixation, research on hydrogenase chemistry is particularly driven by the view that understanding active-site structure and function will inform the design of new materials for hydrogen production or uptake, pertinent to energy transduction technology and a hydrogen economy. Herein we report the assembly of the first materials with di-iron sub-sites linked by a thiolate bridge to a (4Fe4S) ? cluster, as found at the active site of the iron-only hydrogenase, the H-cluster.

  4. Reversible [4Fe-3S] cluster morphing in an O(2)-tolerant [NiFe] hydrogenase.

    PubMed

    Frielingsdorf, Stefan; Fritsch, Johannes; Schmidt, Andrea; Hammer, Mathias; Löwenstein, Julia; Siebert, Elisabeth; Pelmenschikov, Vladimir; Jaenicke, Tina; Kalms, Jacqueline; Rippers, Yvonne; Lendzian, Friedhelm; Zebger, Ingo; Teutloff, Christian; Kaupp, Martin; Bittl, Robert; Hildebrandt, Peter; Friedrich, Bärbel; Lenz, Oliver; Scheerer, Patrick

    2014-05-01

    Hydrogenases catalyze the reversible oxidation of H(2) into protons and electrons and are usually readily inactivated by O(2). However, a subgroup of the [NiFe] hydrogenases, including the membrane-bound [NiFe] hydrogenase from Ralstonia eutropha, has evolved remarkable tolerance toward O(2) that enables their host organisms to utilize H(2) as an energy source at high O(2). This feature is crucially based on a unique six cysteine-coordinated [4Fe-3S] cluster located close to the catalytic center, whose properties were investigated in this study using a multidisciplinary approach. The [4Fe-3S] cluster undergoes redox-dependent reversible transformations, namely iron swapping between a sulfide and a peptide amide N. Moreover, our investigations unraveled the redox-dependent and reversible occurence of an oxygen ligand located at a different iron. This ligand is hydrogen bonded to a conserved histidine that is essential for H(2) oxidation at high O(2). We propose that these transformations, reminiscent of those of the P-cluster of nitrogenase, enable the consecutive transfer of two electrons within a physiological potential range. PMID:24705592

  5. Immobilized chloroplast-ferredoxin-hydrogenase system for the simultaneous photoproduction of hydrogen and oxygen

    SciTech Connect

    Woodward, J.; Greenbaum, E.

    1983-01-01

    The chloroplast-ferredoxin-hydrogenase (CFH) system is capable of the simultaneous photoproduction of hydrogen and oxygen using water as the source of electrons. The immobilization of chloroplasts and hydrogenase, which has been the subject of several reports has been attempted in order to increase their storage and functional stability. However, immobilized chloroplasts and hydrogenase have never been shown to produce hydrogen and oxygen simultaneously. The simultaneous photoproduction of hydrogen and oxygen is a valuable guide in assessing the role of water as the primary substrate in biophotolysis. As has been shown previously, the stoichiometric ratio of hydrogen to oxygen is, in general, not equal to 2. By measuring the oxygen that is produced along with the hydrogen, it is possible to set an upper limit on the photoproduced hydrogen that is derive d from water. The study reported here describes for the first time the simultaneous photoproduction of hydrogen and oxygen by the CFH system immobilized in calcium alginate gel spheres. 15 references, 4 figures.

  6. Robust Prognostic Gene Expression Signatures in Bladder Cancer and Lung Adenocarcinoma Depend on Cell Cycle Related Genes

    PubMed Central

    Dancik, Garrett M.; Theodorescu, Dan

    2014-01-01

    Few prognostic biomarkers are approved for clinical use primarily because their initial performance cannot be repeated in independent datasets. We posited that robust biomarkers could be obtained by identifying deregulated biological processes shared among tumor types having a common etiology. We performed a gene set enrichment analysis in 20 publicly available gene expression datasets comprising 1968 patients having one of the three most common tobacco-related cancers (lung, bladder, head and neck) and identified cell cycle related genes as the most consistently prognostic class of biomarkers in bladder (BL) and lung adenocarcinoma (LUAD). We also found the prognostic value of 13 of 14 published BL and LUAD signatures were dependent on cell cycle related genes, supporting the importance of cell cycle related biomarkers for prognosis. Interestingly, no prognostic gene classes were identified in squamous cell lung carcinoma or head and neck squamous cell carcinoma. Next, a specific 31 gene cell cycle proliferation (CCP) signature, previously derived in prostate tumors was evaluated and found predictive of outcome in BL and LUAD cohorts in univariate and multivariate analyses. Specifically, CCP score significantly enhanced the predictive ability of multivariate models based on standard clinical variables for progression in BL patients and survival in LUAD patients in multiple cohorts. We then generated random CCP signatures of various sizes and found sets of 10–15 genes had robust performance in these BL and LUAD cohorts, a finding that was confirmed in an independent cohort. Our work characterizes the importance of cell cycle related genes in prognostic signatures for BL and LUAD patients and identifies a specific signature likely to survive additional validation. PMID:24465512

  7. Merging [FeFe]-hydrogenases with materials and nanomaterials as biohybrid catalysts for solar H II production

    NASA Astrophysics Data System (ADS)

    King, Paul W.; Svedruzic, Drazenka; Hambourger, Michael; Gervaldo, Miguel; McDonald, Tim; Blackburn, Jeff; Heben, Michael; Gust, Devens; Moore, Ana L.; Moore, Thomas A.; Ghirardi, Maria L.

    2007-09-01

    The catalysts commonly used for the H II producing reaction in artificial solar systems are typically platinum or particulate platinum composites. Biological catalysts, the hydrogenases, exist in a wide-variety of microbes and are biosynthesized from abundant, non-precious metals. By virtue of a unique catalytic metallo-cluster that is composed of iron and sulfur, [FeFe]-hydrogenases are capable of catalyzing H II production at turnover rates of millimoles-per-second. In addition, these biological catalysts possess some of the characteristics that are desired for cost-effective solar H II production systems, high solubilities in aqueous solutions and low activation energies, but are sensitive to CO and O II. We are investigating ways to merge [FeFe]-hydrogenases with a variety of organic materials and nanomaterials for the fabrication of electrodes and biohybrids as catalysts for use in artificial solar H II production systems. These efforts include designs that allow for the integration of [FeFe]-hydrogenase in dye-solar cells as models to measure solar conversion and H II production efficiencies. In support of a more fundamental understanding of [FeFe]-hydrogenase for these and other applications the role of protein structure in catalysis is being investigated. Currently there is little known about the mechanism of how these and other enzymes couple multi-electron transfer to proton reduction. To further the mechanistic understanding of [FeFe]-hydrogenases, structural models for substrate transfer are being used to create enzyme variants for biochemical analysis. Here results are presented on investigations of proton-transfer pathways in [FeFe]-hydrogenase and their interaction with single-walled carbon nanotubes.

  8. Characterizing Milk Production Related Genes in Holstein Using RNA-seq

    PubMed Central

    Seo, Minseok; Lee, Hyun-Jeong; Kim, Kwondo; Caetano-Anolles, Kelsey; Jeong, Jin Young; Park, Sungkwon; Oh, Young Kyun; Cho, Seoae; Kim, Heebal

    2016-01-01

    Although the chemical, physical, and nutritional properties of bovine milk have been extensively studied, only a few studies have attempted to characterize milk-synthesizing genes using RNA-seq data. RNA-seq data was collected from 21 Holstein samples, along with group information about milk production ability; milk yield; and protein, fat, and solid contents. Meta-analysis was employed in order to generally characterize genes related to milk production. In addition, we attempted to investigate the relationship between milk related traits, parity, and lactation period. We observed that milk fat is highly correlated with lactation period; this result indicates that this effect should be considered in the model in order to accurately detect milk production related genes. By employing our developed model, 271 genes were significantly (false discovery rate [FDR] adjusted p-value<0.1) detected as milk production related differentially expressed genes. Of these genes, five (albumin, nitric oxide synthase 3, RNA-binding region (RNP1, RRM) containing 3, secreted and transmembrane 1, and serine palmitoyltransferase, small subunit B) were technically validated using quantitative real-time polymerase chain reaction (qRT-PCR) in order to check the accuracy of RNA-seq analysis. Finally, 83 gene ontology biological processes including several blood vessel and mammary gland development related terms, were significantly detected using DAVID gene-set enrichment analysis. From these results, we observed that detected milk production related genes are highly enriched in the circulation system process and mammary gland related biological functions. In addition, we observed that detected genes including caveolin 1, mammary serum amyloid A3.2, lingual antimicrobial peptide, cathelicidin 4 (CATHL4), cathelicidin 6 (CATHL6) have been reported in other species as milk production related gene. For this reason, we concluded that our detected 271 genes would be strong candidates for

  9. The PMP22 Gene and Its Related Diseases

    PubMed Central

    Li, Jun; Parker, Brett; Martyn, Colin; Natarajan, Chandramohan; Guo, Jiasong

    2012-01-01

    Peripheral myelin protein-22 (PMP22) is primarily expressed in the compact myelin of the peripheral nervous system. Levels of PMP22 have to be tightly regulated since alterations of PMP22 levels by mutations of the PMP22 gene are responsible for >50% of all patients with inherited peripheral neuropathies, including Charcot-Marie-Tooth type-1A (CMT1A) with trisomy of PMP22, hereditary neuropathy with liability to pressure palsies (HNPP) with heterozygous deletion of PMP22, and CMT1E with point mutations of PMP22. While over-expression and point-mutations of the PMP22 gene may produce gain-of-function phenotypes, deletion of PMP22 results in a loss-of-function phenotype that reveals the normal physiological functions of the PMP22 protein. In this article, we will review the basic genetics, biochemistry and molecular structure of PMP22, followed by discussion of the current understanding of pathogenic mechanisms involving in the inherited neuropathies with mutations in PMP22 gene. PMID:23224996

  10. Daily differential expression of melatonin-related genes and clock genes in rat cumulus-oocyte complex: changes after pinealectomy.

    PubMed

    Coelho, L A; Peres, R; Amaral, F G; Reiter, R J; Cipolla-Neto, J

    2015-05-01

    This study investigated the maturational stage (immature and mature ovaries) differences of mRNA expression of melatonin-forming enzymes (Aanat and Asmt), melatonin membrane receptors (Mt1 and Mt2) and putative nuclear (Rorα) receptors, and clock genes (Clock, Bmal1, Per1, Per2, Cry1, Cry2) in cumulus-oocyte complexes (COC) from weaning Wistar rats. We also examined the effects of pinealectomy and of melatonin pharmacological replacement on the daily expression of these genes in COC. qRT-PCR analysis revealed that in oocytes, the mRNA expression of Asmt, Mt2, Clock, Bmal1, Per2, and Cry1 were higher (P < 0.05) in immature ovaries than in the mature ones. In cumulus cells, the same pattern of mRNA expression for Asmt, Aanat, Rorα, Clock, Per1, Cry1, and Cry2 genes was observed. In oocytes, pinealectomy altered the daily mRNA expression profiles of Asmt, Mt1, Mt2, Clock, Per1, Cry1, and Cry2 genes. In cumulus cells, removal of the pineal altered the mRNA expression profiles of Mt1, Mt2, Rorα, Aanat, Asmt, Clock, Bmal1, Per2, Cry1, and Cry2 genes. Melatonin treatment partially or completely re-established the daily mRNA expression profiles of most genes studied. The mRNA expression of melatonin-related genes and clock genes in rat COC varies with the maturational stage of the meiotic cellular cycle in addition to the hour of the day. This suggests that melatonin might act differentially in accordance with the maturational stage of cumulus/oocyte complex. In addition, it seems that circulating pineal melatonin is very important in the design of the daily profile of mRNA expression of COC clock genes and genes related to melatonin synthesis and action.

  11. A Genome-Wide Screen Indicates Correlation between Differentiation and Expression of Metabolism Related Genes

    PubMed Central

    Shende, Akhilesh; Singh, Anupama; Meena, Anil; Ghosal, Ritika; Ranganathan, Madhav; Bandyopadhyay, Amitabha

    2013-01-01

    Differentiated tissues may be considered as materials with distinct properties. The differentiation program of a given tissue ensures that it acquires material properties commensurate with its function. It may be hypothesized that some of these properties are acquired through production of tissue-specific metabolites synthesized by metabolic enzymes. To establish correlation between metabolism and organogenesis we have carried out a genome-wide expression study of metabolism related genes by RNA in-situ hybridization. 23% of the metabolism related genes studied are expressed in a tissue-restricted but not tissue-exclusive manner. We have conducted the screen on whole mount chicken (Gallus gallus) embryos from four distinct developmental stages to correlate dynamic changes in expression patterns of metabolic enzymes with spatio-temporally unique developmental events. Our data strongly suggests that unique combinations of metabolism related genes, and not specific metabolic pathways, are upregulated during differentiation. Further, expression of metabolism related genes in well established signaling centers that regulate different aspects of morphogenesis indicates developmental roles of some of the metabolism related genes. The database of tissue-restricted expression patterns of metabolism related genes, generated in this study, should serve as a resource for systematic identification of these genes with tissue-specific functions during development. Finally, comprehensive understanding of differentiation is not possible unless the downstream genes of a differentiation cascade are identified. We propose, metabolic enzymes constitute a significant portion of these downstream target genes. Thus our study should help elucidate different aspects of tissue differentiation. PMID:23717462

  12. Identification of Cancer Related Genes Using a Comprehensive Map of Human Gene Expression

    PubMed Central

    Lukk, Margus; Xue, Vincent; Parkinson, Helen; Rung, Johan; Brazma, Alvis

    2016-01-01

    Rapid accumulation and availability of gene expression datasets in public repositories have enabled large-scale meta-analyses of combined data. The richness of cross-experiment data has provided new biological insights, including identification of new cancer genes. In this study, we compiled a human gene expression dataset from ∼40,000 publicly available Affymetrix HG-U133Plus2 arrays. After strict quality control and data normalisation the data was quantified in an expression matrix of ∼20,000 genes and ∼28,000 samples. To enable different ways of sample grouping, existing annotations where subjected to systematic ontology assisted categorisation and manual curation. Groups like normal tissues, neoplasmic tissues, cell lines, homoeotic cells and incompletely differentiated cells were created. Unsupervised analysis of the data confirmed global structure of expression consistent with earlier analysis but with more details revealed due to increased resolution. A suitable mixed-effects linear model was used to further investigate gene expression in solid tissue tumours, and to compare these with the respective healthy solid tissues. The analysis identified 1,285 genes with systematic expression change in cancer. The list is significantly enriched with known cancer genes from large, public, peer-reviewed databases, whereas the remaining ones are proposed as new cancer gene candidates. The compiled dataset is publicly available in the ArrayExpress Archive. It contains the most diverse collection of biological samples, making it the largest systematically annotated gene expression dataset of its kind in the public domain. PMID:27322383

  13. Human speech- and reading-related genes display partially overlapping expression patterns in the marmoset brain.

    PubMed

    Kato, Masaki; Okanoya, Kazuo; Koike, Taku; Sasaki, Erika; Okano, Hideyuki; Watanabe, Shigeru; Iriki, Atsushi

    2014-06-01

    Language is a characteristic feature of human communication. Several familial language impairments have been identified, and candidate genes for language impairments already isolated. Studies comparing expression patterns of these genes in human brain are necessary to further understanding of these genes. However, it is difficult to examine gene expression in human brain. In this study, we used a non-human primate (common marmoset; Callithrix jacchus) as a biological model of the human brain to investigate expression patterns of human speech- and reading-related genes. Expression patterns of speech disorder- (FoxP2, FoxP1, CNTNAP2, and CMIP) and dyslexia- (ROBO1, DCDC2, and KIAA0319) related genes were analyzed. We found the genes displayed overlapping expression patterns in the ocular, auditory, and motor systems. Our results enhance understanding of the molecular mechanisms underlying language impairments.

  14. Genes related to immunity, as expressed in the alfalfa leafcutting bee, Megachile rotundata, during pathogen challenge.

    PubMed

    Xu, J; James, R

    2009-11-01

    Virtually nothing is known about disease resistance in solitary bees, so expressed sequence tag (EST) databases were developed to search for immune response genes in the alfalfa leafcutting bee. We identified 104 putative immunity-related genes from both healthy and pathogen-challenged bee larvae, and 12 more genes using PCR amplification. The genes identified coded for proteins with a wide variety of innate immune response functions, including pathogen recognition, phagocytosis, the prophenoloxidase cascade, melanization, coagulation and several signalling pathways. Some immune response genes were highly conserved with honey bee genes, and more distantly related to other insects. The data presented provides the first analysis of immune function in a solitary bee and provides a foundation for the further analysis of gene expression patterns in bees. PMID:19863668

  15. Gene expression analysis of precision-cut human liver slices indicates stable expression of ADME-Tox related genes

    SciTech Connect

    Elferink, M.G.L.; Olinga, P.; van Leeuwen, E.M.; Bauerschmidt, S.; Polman, J.; Schoonen, W.G.; Heisterkamp, S.H.; Groothuis, G.M.M.

    2011-05-15

    In the process of drug development it is of high importance to test the safety of new drugs with predictive value for human toxicity. A promising approach of toxicity testing is based on shifts in gene expression profiling of the liver. Toxicity screening based on animal liver cells cannot be directly extrapolated to humans due to species differences. The aim of this study was to evaluate precision-cut human liver slices as in vitro method for the prediction of human specific toxicity by toxicogenomics. The liver slices contain all cell types of the liver in their natural architecture. This is important since drug-induced toxicity often is a multi-cellular process. Previously we showed that toxicogenomic analysis of rat liver slices is highly predictive for rat in vivo toxicity. In this study we investigated the levels of gene expression during incubation up to 24 h with Affymetrix microarray technology. The analysis was focused on a broad spectrum of genes related to stress and toxicity, and on genes encoding for phase-I, -II and -III metabolizing enzymes and transporters. Observed changes in gene expression were associated with cytoskeleton remodeling, extracellular matrix and cell adhesion, but for the ADME-Tox related genes only minor changes were observed. PCA analysis showed that changes in gene expression were not associated with age, sex or source of the human livers. Slices treated with acetaminophen showed patterns of gene expression related to its toxicity. These results indicate that precision-cut human liver slices are relatively stable during 24 h of incubation and represent a valuable model for human in vitro hepatotoxicity testing despite the human inter-individual variability.

  16. Genome-Wide Gene Expression in relation to Age in Large Laboratory Cohorts of Drosophila melanogaster

    PubMed Central

    Carlson, Kimberly A.; Gardner, Kylee; Pashaj, Anjeza; Carlson, Darby J.; Yu, Fang; Eudy, James D.; Zhang, Chi; Harshman, Lawrence G.

    2015-01-01

    Aging is a complex process characterized by a steady decline in an organism's ability to perform life-sustaining tasks. In the present study, two cages of approximately 12,000 mated Drosophila melanogaster females were used as a source of RNA from individuals sampled frequently as a function of age. A linear model for microarray data method was used for the microarray analysis to adjust for the box effect; it identified 1,581 candidate aging genes. Cluster analyses using a self-organizing map algorithm on the 1,581 significant genes identified gene expression patterns across different ages. Genes involved in immune system function and regulation, chorion assembly and function, and metabolism were all significantly differentially expressed as a function of age. The temporal pattern of data indicated that gene expression related to aging is affected relatively early in life span. In addition, the temporal variance in gene expression in immune function genes was compared to a random set of genes. There was an increase in the variance of gene expression within each cohort, which was not observed in the set of random genes. This observation is compatible with the hypothesis that D. melanogaster immune function genes lose control of gene expression as flies age. PMID:26090231

  17. NADP-specific electron-bifurcating [FeFe]-hydrogenase in a functional complex with formate dehydrogenase in Clostridium autoethanogenum grown on CO.

    PubMed

    Wang, Shuning; Huang, Haiyan; Kahnt, Jörg; Mueller, Alexander P; Köpke, Michael; Thauer, Rudolf K

    2013-10-01

    Flavin-based electron bifurcation is a recently discovered mechanism of coupling endergonic to exergonic redox reactions in the cytoplasm of anaerobic bacteria and archaea. Among the five electron-bifurcating enzyme complexes characterized to date, one is a heteromeric ferredoxin- and NAD-dependent [FeFe]-hydrogenase. We report here a novel electron-bifurcating [FeFe]-hydrogenase that is NADP rather than NAD specific and forms a complex with a formate dehydrogenase. The complex was found in high concentrations (6% of the cytoplasmic proteins) in the acetogenic Clostridium autoethanogenum autotrophically grown on CO, which was fermented to acetate, ethanol, and 2,3-butanediol. The purified complex was composed of seven different subunits. As predicted from the sequence of the encoding clustered genes (fdhA/hytA-E) and from chemical analyses, the 78.8-kDa subunit (FdhA) is a selenocysteine- and tungsten-containing formate dehydrogenase, the 65.5-kDa subunit (HytB) is an iron-sulfur flavin mononucleotide protein harboring the NADP binding site, the 51.4-kDa subunit (HytA) is the [FeFe]-hydrogenase proper, and the 18.1-kDa (HytC), 28.6-kDa (HytD), 19.9-kDa (HytE1), and 20.1-kDa (HytE2) subunits are iron-sulfur proteins. The complex catalyzed both the reversible coupled reduction of ferredoxin and NADP(+) with H2 or formate and the reversible formation of H2 and CO2 from formate. We propose the complex to have two functions in vivo, namely, to normally catalyze CO2 reduction to formate with NADPH and reduced ferredoxin in the Wood-Ljungdahl pathway and to catalyze H2 formation from NADPH and reduced ferredoxin when these redox mediators get too reduced during unbalanced growth of C. autoethanogenum on CO (E0' = -520 mV).

  18. NADP-Specific Electron-Bifurcating [FeFe]-Hydrogenase in a Functional Complex with Formate Dehydrogenase in Clostridium autoethanogenum Grown on CO

    PubMed Central

    Wang, Shuning; Huang, Haiyan; Kahnt, Jörg; Mueller, Alexander P.; Köpke, Michael

    2013-01-01

    Flavin-based electron bifurcation is a recently discovered mechanism of coupling endergonic to exergonic redox reactions in the cytoplasm of anaerobic bacteria and archaea. Among the five electron-bifurcating enzyme complexes characterized to date, one is a heteromeric ferredoxin- and NAD-dependent [FeFe]-hydrogenase. We report here a novel electron-bifurcating [FeFe]-hydrogenase that is NADP rather than NAD specific and forms a complex with a formate dehydrogenase. The complex was found in high concentrations (6% of the cytoplasmic proteins) in the acetogenic Clostridium autoethanogenum autotrophically grown on CO, which was fermented to acetate, ethanol, and 2,3-butanediol. The purified complex was composed of seven different subunits. As predicted from the sequence of the encoding clustered genes (fdhA/hytA-E) and from chemical analyses, the 78.8-kDa subunit (FdhA) is a selenocysteine- and tungsten-containing formate dehydrogenase, the 65.5-kDa subunit (HytB) is an iron-sulfur flavin mononucleotide protein harboring the NADP binding site, the 51.4-kDa subunit (HytA) is the [FeFe]-hydrogenase proper, and the 18.1-kDa (HytC), 28.6-kDa (HytD), 19.9-kDa (HytE1), and 20.1-kDa (HytE2) subunits are iron-sulfur proteins. The complex catalyzed both the reversible coupled reduction of ferredoxin and NADP+ with H2 or formate and the reversible formation of H2 and CO2 from formate. We propose the complex to have two functions in vivo, namely, to normally catalyze CO2 reduction to formate with NADPH and reduced ferredoxin in the Wood-Ljungdahl pathway and to catalyze H2 formation from NADPH and reduced ferredoxin when these redox mediators get too reduced during unbalanced growth of C. autoethanogenum on CO (E0′ = −520 mV). PMID:23893107

  19. Circadian rhythm-related genes: implication in autoimmunity and type 1 diabetes.

    PubMed

    Lebailly, B; Boitard, C; Rogner, U C

    2015-09-01

    Recent gene association and functional studies have proven the implication of several circadian rhythm-related genes in diabetes. Diabetes has been related to variation in central circadian regulation and peripheral oscillation. Different transcriptional regulators have been identified. Circadian genes are clearly implicated in metabolic pathways, pancreatic function and in type 2 diabetes. Much less evidence has been shown for the link between circadian regulation and type 1 diabetes. The hypothesis that circadian genes are involved in type 1 diabetes is reinforced by findings that the immune system undergoes circadian variation and that several autoimmune diseases are associated with circadian genes. Recent findings in the non-obese diabetic mouse model pinpoint to specific mechanisms controlling type 1 diabetes by the clock-related gene Arntl2 in the immune system.

  20. Gene Expression Changes for Antioxidants Pathways in the Mouse Cochlea: Relations to Age-related Hearing Deficits

    PubMed Central

    Tadros, Sherif F.; D'Souza, Mary; Zhu, Xiaoxia; Frisina, Robert D.

    2014-01-01

    Age-related hearing loss – presbycusis – is the number one neurodegenerative disorder and top communication deficit of our aged population. Like many aging disorders of the nervous system, damage from free radicals linked to production of reactive oxygen and/or nitrogen species (ROS and RNS, respectively) may play key roles in disease progression. The efficacy of the antioxidant systems, e.g., glutathione and thioredoxin, is an important factor in pathophysiology of the aging nervous system. In this investigation, relations between the expression of antioxidant-related genes in the auditory portion of the inner ear – cochlea, and age-related hearing loss was explored for CBA/CaJ mice. Forty mice were classified into four groups according to age and degree of hearing loss. Cochlear mRNA samples were collected and cDNA generated. Using Affymetrix® GeneChip, the expressions of 56 antioxidant-related gene probes were analyzed to estimate the differences in gene expression between the four subject groups. The expression of Glutathione peroxidase 6, Gpx6; Thioredoxin reductase 1, Txnrd1; Isocitrate dehydrogenase 1, Idh1; and Heat shock protein 1, Hspb1; were significantly different, or showed large fold-change differences between subject groups. The Gpx6, Txnrd1 and Hspb1 gene expression changes were validated using qPCR. The Gpx6 gene was upregulated while the Txnrd1 gene was downregulated with age/hearing loss. The Hspb1 gene was found to be downregulated in middle-aged animals as well as those with mild presbycusis, whereas it was upregulated in those with severe presbycusis. These results facilitate development of future interventions to predict, prevent or slow down the progression of presbycusis. PMID:24587312

  1. Gene expression changes for antioxidants pathways in the mouse cochlea: relations to age-related hearing deficits.

    PubMed

    Tadros, Sherif F; D'Souza, Mary; Zhu, Xiaoxia; Frisina, Robert D

    2014-01-01

    Age-related hearing loss - presbycusis - is the number one neurodegenerative disorder and top communication deficit of our aged population. Like many aging disorders of the nervous system, damage from free radicals linked to production of reactive oxygen and/or nitrogen species (ROS and RNS, respectively) may play key roles in disease progression. The efficacy of the antioxidant systems, e.g., glutathione and thioredoxin, is an important factor in pathophysiology of the aging nervous system. In this investigation, relations between the expression of antioxidant-related genes in the auditory portion of the inner ear - cochlea, and age-related hearing loss was explored for CBA/CaJ mice. Forty mice were classified into four groups according to age and degree of hearing loss. Cochlear mRNA samples were collected and cDNA generated. Using Affymetrix® GeneChip, the expressions of 56 antioxidant-related gene probes were analyzed to estimate the differences in gene expression between the four subject groups. The expression of Glutathione peroxidase 6, Gpx6; Thioredoxin reductase 1, Txnrd1; Isocitrate dehydrogenase 1, Idh1; and Heat shock protein 1, Hspb1; were significantly different, or showed large fold-change differences between subject groups. The Gpx6, Txnrd1 and Hspb1 gene expression changes were validated using qPCR. The Gpx6 gene was upregulated while the Txnrd1 gene was downregulated with age/hearing loss. The Hspb1 gene was found to be downregulated in middle-aged animals as well as those with mild presbycusis, whereas it was upregulated in those with severe presbycusis. These results facilitate development of future interventions to predict, prevent or slow down the progression of presbycusis.

  2. Functional features, biological pathways, and protein interaction networks of addiction-related genes.

    PubMed

    Sun, Jingchun; Zhao, Zhongming

    2010-05-01

    Addictions are chronic and common brain disorders affected by many genetic, environmental, and behavioral factors. Recent genome-wide linkage and association studies have revealed several promising genomic regions and multiple genes relating to addictions. To explore the underlying biological processes in the development of addictions, we used 62 genes recently reviewed by Li and Burmeister (2009) as representative addiction-related genes, and then we investigated their features in gene function, pathways, and protein interaction networks. We performed enrichment tests of their Gene Ontology (GO) annotations and of their pathways in the Ingenuity Pathways Analysis (IPA) system. The tests revealed that these addiction-related genes were highly enriched in neurodevelopment-related processes. Interestingly, we found circadian rhythm signaling in one of the enriched pathways. Moreover, these addiction-related genes tended to have higher connectivity and shorter characteristic shortest-path distances compared to control genes in the protein-protein interaction (PPI) network. This investigation is the first of such kind in addiction studies, and it is useful for further addiction candidate-gene prioritization and verification, thus helping us to better understand molecular mechanisms of addictions.

  3. An Innovative Cloning Platform Enables Large-Scale Production and Maturation of an Oxygen-Tolerant [NiFe]-Hydrogenase from Cupriavidus necator in Escherichia coli

    PubMed Central

    Schiffels, Johannes; Pinkenburg, Olaf; Schelden, Maximilian; Aboulnaga, El-Hussiny A. A.; Baumann, Marcus E. M.; Selmer, Thorsten

    2013-01-01

    Expression of multiple heterologous genes in a dedicated host is a prerequisite for approaches in synthetic biology, spanning from the production of recombinant multiprotein complexes to the transfer of tailor-made metabolic pathways. Such attempts are often exacerbated, due in most cases to a lack of proper directional, robust and readily accessible genetic tools. Here, we introduce an innovative system for cloning and expression of multiple genes in Escherichia coli BL21 (DE3). Using the novel methodology, genes are equipped with individual promoters and terminators and subsequently assembled. The resulting multiple gene cassettes may either be placed in one vector or alternatively distributed among a set of compatible plasmids. We demonstrate the effectiveness of the developed tool by production and maturation of the NAD+reducing soluble [NiFe]-hydrogenase (SH) from Cupriavidus necator H16 (formerly Ralstonia eutropha H16) in E. coli BL21Star™ (DE3). The SH (encoded in hoxFUYHI) was successfully matured by co-expression of a dedicated set of auxiliary genes, comprising seven hyp genes (hypC1D1E1A2B2F2X) along with hoxW, which encodes a specific endopeptidase. Deletion of genes involved in SH maturation reduced maturation efficiency substantially. Further addition of hoxN1, encoding a high-affinity nickel permease from C. necator, considerably increased maturation efficiency in E. coli. Carefully balanced growth conditions enabled hydrogenase production at high cell-densities, scoring mg·(Liter culture)−1 yields of purified functional SH. Specific activities of up to 7.2±1.15 U·mg−1 were obtained in cell-free extracts, which is in the range of the highest activities ever determined in C. necator extracts. The recombinant enzyme was isolated in equal purity and stability as previously achieved with the native form, yielding ultrapure preparations with anaerobic specific activities of up to 230 U·mg−1. Owing to the combinatorial power exhibited by the

  4. Characterization of the Community Structure of a Dechlorinating Mixed Culture and Comparisons of Gene Expression in Planktonic and Biofloc-Associated “Dehalococcoides” and Methanospirillum Species▿ †

    PubMed Central

    Rowe, Annette R.; Lazar, Brendan J.; Morris, Robert M.; Richardson, Ruth E.

    2008-01-01

    This study sought to characterize bacterial and archaeal populations in a perchloroethene- and butyrate-fed enrichment culture containing hydrogen-consuming “Dehalococcoides ethenogenes” strain 195 and a Methanospirillum hungatei strain. Phylogenetic characterization of this microbial community was done via 16S rRNA gene clone library and gradient gel electrophoresis analyses. Fluorescence in situ hybridization was used to quantify populations of “Dehalococcoides” and Archaea and to examine the colocalization of these two groups within culture bioflocs. A technique for enrichment of planktonic and biofloc-associated biomass was developed and used to assess differences in population distribution and gene expression patterns following provision of substrate. On a per-milliliter-of-culture basis, most D. ethenogenes genes (the hydrogenase gene hupL; the highly expressed gene for an oxidoreductase of unknown function, fdhA; the RNA polymerase subunit gene rpoB; and the 16S rRNA gene) showed no statistical difference in expression between planktonic and biofloc enrichments at either time point studied (1 to 2 and 6 h postfeeding). Normalization of transcripts to ribosome (16S rRNA) levels supported that planktonic and biofloc-associated D. ethenogenes had similar gene expression profiles, with one notable exception; planktonic D. ethenogenes showed higher expression of tceA relative to biofloc-associated cells at 6 h postfeeding. These trends were compared to those for the hydrogen-consuming methanogen in the culture, M. hungatei. The vast majority of M. hungatei cells, ribosomes (16S rRNA), and transcripts of the hydrogenase gene mvrD and the housekeeping gene rpoE were observed in the biofloc enrichments. This suggests that, unlike the comparable activity of D. ethenogenes from both enrichments, planktonic M. hungatei is responsible for only a small fraction of the hydrogenotrophic methanogenesis in this culture. PMID:18776027

  5. Characterization of the community structure of a dechlorinating mixed culture and comparisons of gene expression in planktonic and biofloc-associated "Dehalococcoides" and Methanospirillum species.

    PubMed

    Rowe, Annette R; Lazar, Brendan J; Morris, Robert M; Richardson, Ruth E

    2008-11-01

    This study sought to characterize bacterial and archaeal populations in a perchloroethene- and butyrate-fed enrichment culture containing hydrogen-consuming "Dehalococcoides ethenogenes" strain 195 and a Methanospirillum hungatei strain. Phylogenetic characterization of this microbial community was done via 16S rRNA gene clone library and gradient gel electrophoresis analyses. Fluorescence in situ hybridization was used to quantify populations of "Dehalococcoides" and Archaea and to examine the colocalization of these two groups within culture bioflocs. A technique for enrichment of planktonic and biofloc-associated biomass was developed and used to assess differences in population distribution and gene expression patterns following provision of substrate. On a per-milliliter-of-culture basis, most D. ethenogenes genes (the hydrogenase gene hupL; the highly expressed gene for an oxidoreductase of unknown function, fdhA; the RNA polymerase subunit gene rpoB; and the 16S rRNA gene) showed no statistical difference in expression between planktonic and biofloc enrichments at either time point studied (1 to 2 and 6 h postfeeding). Normalization of transcripts to ribosome (16S rRNA) levels supported that planktonic and biofloc-associated D. ethenogenes had similar gene expression profiles, with one notable exception; planktonic D. ethenogenes showed higher expression of tceA relative to biofloc-associated cells at 6 h postfeeding. These trends were compared to those for the hydrogen-consuming methanogen in the culture, M. hungatei. The vast majority of M. hungatei cells, ribosomes (16S rRNA), and transcripts of the hydrogenase gene mvrD and the housekeeping gene rpoE were observed in the biofloc enrichments. This suggests that, unlike the comparable activity of D. ethenogenes from both enrichments, planktonic M. hungatei is responsible for only a small fraction of the hydrogenotrophic methanogenesis in this culture. PMID:18776027

  6. LIS1 Lissencephaly gene CNS expression: Relation to neuronal migration

    SciTech Connect

    Reiner, O. |; Gal-Gerber, O.; Sapir, T.

    1994-09-01

    Lis1 is the murine gene corresponding to human LIS1 gene involved in Miller-Dieker lissencephaly located on chromosome 17p13.3 as demonstrated by cDNA cloning, sequence analysis and genetic mapping. Lis1 expression was studied in developing mouse brain using in situ hybridization. At embryonic day 15, Lis1 expression was most prominently localized in the neuronal layer of the retina, the developing hippocampus, doral root ganglia, cranial ganglia and the thalamus. At postnatal day 5 a unique pattern of expression was detected in the developing cerebellum. Lis1 was expressed at high levels in the Purkinje cell layer when the granule cells were migrating through the Purkinje cell layer inwards. The expression of Lis1 in Purkinje cells in the adult is markedly reduced. Similarly, Lis1 was expressed in the ontogenetically older layers of the neocortex (layers 5 and 6) where younger neurons have to migrate through to settle in the superficial layers. Thus, at both sites a link between expression and neuronal migration was demonstrated. These studies on the expression pattern of Lis1 could be useful in understanding abnormalities in Miller-Dieker lissencephaly syndrome (MDS) patients.

  7. Halotolerant and Resistant to High pH Hydrogenase from Haloalkaliphilic Sulfate-Reducing Bacterium Desulfonatronum thiodismutans

    NASA Technical Reports Server (NTRS)

    Detkova, Ekaterina N.; Pikuta, Elena V.; Hoover, Richard B.

    2004-01-01

    Hydrogenase is the key enzyme of energetic metabolism in cells, it catalyzing the converse reaction of hydrogen oxidation and responsible for consumption and excretion of hydrogen in bacteria. Hydrogenases are proteins containing either Nickel and Iron, or the only Iron in theirs active center. Hydrogenases have been found in many microorganisms, such as Methanogenic, acetogenic, nitrogen-fixing, photosynthetic and sulfate-reducing bacteria that could utilize the hydrogen as energy source or use it as electron sink. Hydrogenases are subject for wide physiological, biochemical, physicochemical and genetic studies due to theirs abilities produce the molecular hydrogen as alternative source of pure energy. Notwithstanding on enough large quantity of works that deal with intracellular and extrasellular enzymes of halophilic bacteria, the data about hydrogenases and theirs functions of salts practically are absent. The study of hydrogenase in cell-free extracts of extremely halophilic eubacterium Acetohalobium mabaticum showed dramatic increasing activity of the enzyme at high concentrations of NaCl and KCI (close to saturated solution). Here we present the data of free-cells extracted hydrogenase from new haloalkaliphilic sulfate-reducing bacterium Desulfonatronum thiodismutans, which grow on highly miniralized carbonate-bicarbonate medium in salinity range 1 to 7 % and at pH 7.8 - 10.5. Studied enzyme was active in Concentration range from 0 to 4.3 M NaCl with optimum at 1.0 M NaCl. At 1.0 M NaCl the enzyme activity was increased on 20 %, but with changing concentration from 2.1 M to 3.4 M the activity decreased and was kept on constant level. NaHCO3 inhibited hydrogenase activity on more then 30 %. The maximum of enzyme activity was observed at pH 9.5 with limits 7.5 and 11.5 that practically equal to pH optimum of bacterial growth. Therefore the hydrogenase of Desulfanatronum thiodismutans is tolerant to high concentrations of sodium salts and it also resistant to

  8. Salt-tolerant and high-pH-resistant hydrogenase from the haloalkaliphilic, sulfate-reducing bacterium Desulfonatronum thiodismutans

    NASA Astrophysics Data System (ADS)

    Detkova, Ekaterina N.; Pikuta, Elena V.; Hoover, Richard B.

    2004-11-01

    Hydrogenase is the key enzyme of energetic metabolism in cells, catalyzing the converse reaction of hydrogen oxidation and responsible for the consumption and excretion of hydrogen in bacteria. Hydrogenases are proteins, most of which contain either nickel and iron or iron alone in their active center. Hydrogenases have been found in many microorganisms, such as methanogenic, acetogenic, nitrogen-fixing, sulfate-reducing, photosynthetic bacteria, and algae that use the hydrogen as an energy source or as an electron sink. Hydrogenases are the subject of wide physiological, biochemical, physico-chemical and genetic studies due to their abilities to produce molecular hydrogen as an alternative source of energy. Despite the large quantity of work dealing with the intracellular and extracellular enzymes of halophilic bacteria, the data about the response of hydrogenases to salts are practically absent. The study of hydrogenase in cell-free extracts of the extremely halophilic eubacterium Acetohalobium arabaticum showed a dramatic increase in the activity of the enzyme at high concentrations of NaCl and KCl (near saturated solutions). Here we present data about hydrogenase in a free-cell extract from the new halo-alkaliphilic sulfate-reducing bacterium Desulfonatronum thiodismutans, which grows on a highly mineralized carbonate-bicarbonate medium in the salinity range from 1 to 7 % NaCl and at pH 8.0-10.0. The studied enzyme was active in concentration range from 0.0 to 4.3 M NaCl with the optimum at 1.0 M NaCl. At 1.0 M NaCl the enzyme expressed 20 % additional activity, with NaCl concentration changing from 2.1 M to 3.4 M, and then the activity decreased and reached a constant level. Although sodium bicarbonate decreases the hydrogenase activity, the enzyme still showed activity at 60 % of the maximum level at concentration in a near saturated solution (1.2 M NaHCO3). The maximum enzyme activity was observed at pH 9.5 with limits of 7.5 and 11.5, which is practically

  9. Metagenomic Analyses Reveal That Energy Transfer Gene Abundances Can Predict the Syntrophic Potential of Environmental Microbial Communities.

    PubMed

    Oberding, Lisa; Gieg, Lisa M

    2016-01-01

    Hydrocarbon compounds can be biodegraded by anaerobic microorganisms to form methane through an energetically interdependent metabolic process known as syntrophy. The microorganisms that perform this process as well as the energy transfer mechanisms involved are difficult to study and thus are still poorly understood, especially on an environmental scale. Here, metagenomic data was analyzed for specific clusters of orthologous groups (COGs) related to key energy transfer genes thus far identified in syntrophic bacteria, and principal component analysis was used in order to determine whether potentially syntrophic environments could be distinguished using these syntroph related COGs as opposed to universally present COGs. We found that COGs related to hydrogenase and formate dehydrogenase genes were able to distinguish known syntrophic consortia and environments with the potential for syntrophy from non-syntrophic environments, indicating that these COGs could be used as a tool to identify syntrophic hydrocarbon biodegrading environments using metagenomic data. PMID:27681901

  10. Metagenomic Analyses Reveal That Energy Transfer Gene Abundances Can Predict the Syntrophic Potential of Environmental Microbial Communities

    PubMed Central

    Oberding, Lisa; Gieg, Lisa M.

    2016-01-01

    Hydrocarbon compounds can be biodegraded by anaerobic microorganisms to form methane through an energetically interdependent metabolic process known as syntrophy. The microorganisms that perform this process as well as the energy transfer mechanisms involved are difficult to study and thus are still poorly understood, especially on an environmental scale. Here, metagenomic data was analyzed for specific clusters of orthologous groups (COGs) related to key energy transfer genes thus far identified in syntrophic bacteria, and principal component analysis was used in order to determine whether potentially syntrophic environments could be distinguished using these syntroph related COGs as opposed to universally present COGs. We found that COGs related to hydrogenase and formate dehydrogenase genes were able to distinguish known syntrophic consortia and environments with the potential for syntrophy from non-syntrophic environments, indicating that these COGs could be used as a tool to identify syntrophic hydrocarbon biodegrading environments using metagenomic data.

  11. Metagenomic Analyses Reveal That Energy Transfer Gene Abundances Can Predict the Syntrophic Potential of Environmental Microbial Communities

    PubMed Central

    Oberding, Lisa; Gieg, Lisa M.

    2016-01-01

    Hydrocarbon compounds can be biodegraded by anaerobic microorganisms to form methane through an energetically interdependent metabolic process known as syntrophy. The microorganisms that perform this process as well as the energy transfer mechanisms involved are difficult to study and thus are still poorly understood, especially on an environmental scale. Here, metagenomic data was analyzed for specific clusters of orthologous groups (COGs) related to key energy transfer genes thus far identified in syntrophic bacteria, and principal component analysis was used in order to determine whether potentially syntrophic environments could be distinguished using these syntroph related COGs as opposed to universally present COGs. We found that COGs related to hydrogenase and formate dehydrogenase genes were able to distinguish known syntrophic consortia and environments with the potential for syntrophy from non-syntrophic environments, indicating that these COGs could be used as a tool to identify syntrophic hydrocarbon biodegrading environments using metagenomic data. PMID:27681901

  12. Identifying novel resistance genes in rice wild relatives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice blast and sheath blight are major fungal diseases of cultivated rice (Oryza sativa L. ) that limit Arkansas rough rice yields and market potential. Resistance to these diseases has been found in rice wild relatives (Oryza spp.) A collection of these wild relatives originating from outside the U...

  13. Identification, cloning and heterologous expression of active [NiFe]-hydrogenase 2 from Citrobacter sp. SG in Escherichia coli.

    PubMed

    Maier, Johannes A H; Ragozin, Sergey; Jeltsch, Albert

    2015-04-10

    Hydrogen (H2) is a potential alternative energy carrier which only produces water and heat upon combustion. Today, industrial hydrogen production mainly uses thermochemical processes based on fossil fuels or electrolysis of water. Therefore, biotechnological approaches to produce H2 from biomass are an interesting alternative. We introduce here a novel direct hydrogen measurement system using a semiconducting device specific for hydrogen detection. Using this device, a bacterium producing considerable amounts of hydrogen under aerobic cultivation was isolated and identified by 16S ribosomal DNA sequencing as Citrobacter sp. The enzyme responsible for the observed hydrogenase activity was partially purified by 3 chromatographic purification steps and could be identified by peptide mass fingerprinting to be a type 2 [NiFe]-hydrogenase. Expression of the [NiFe]-hydrogenase 2 containing operon from Citrobacter sp. SG in Escherichia coli allowed recombinant hydrogen production. The [NiFe]-hydrogenase 2 identified here may be useful for biotechnological hydrogen production. We speculate that the expression of the hydrogenase in Citrobacter may be an adaptation to growth in acidic conditions.

  14. Genome-wide age-related changes in DNA methylation and gene expression in human PBMCs.

    PubMed

    Steegenga, Wilma T; Boekschoten, Mark V; Lute, Carolien; Hooiveld, Guido J; de Groot, Philip J; Morris, Tiffany J; Teschendorff, Andrew E; Butcher, Lee M; Beck, Stephan; Müller, Michael

    2014-06-01

    Aging is a progressive process that results in the accumulation of intra- and extracellular alterations that in turn contribute to a reduction in health. Age-related changes in DNA methylation have been reported before and may be responsible for aging-induced changes in gene expression, although a causal relationship has yet to be shown. Using genome-wide assays, we analyzed age-induced changes in DNA methylation and their effect on gene expression with and without transient induction with the synthetic transcription modulating agent WY14,643. To demonstrate feasibility of the approach, we isolated peripheral blood mononucleated cells (PBMCs) from five young and five old healthy male volunteers and cultured them with or without WY14,643. Infinium 450K BeadChip and Affymetrix Human Gene 1.1 ST expression array analysis revealed significant differential methylation of at least 5 % (ΔYO > 5 %) at 10,625 CpG sites between young and old subjects, but only a subset of the associated genes were also differentially expressed. Age-related differential methylation of previously reported epigenetic biomarkers of aging including ELOVL2, FHL2, PENK, and KLF14 was confirmed in our study, but these genes did not display an age-related change in gene expression in PBMCs. Bioinformatic analysis revealed that differentially methylated genes that lack an age-related expression change predominantly represent genes involved in carcinogenesis and developmental processes, and expression of most of these genes were silenced in PBMCs. No changes in DNA methylation were found in genes displaying transiently induced changes in gene expression. In conclusion, aging-induced differential methylation often targets developmental genes and occurs mostly without change in gene expression.

  15. Genome-wide age-related changes in DNA methylation and gene expression in human PBMCs.

    PubMed

    Steegenga, Wilma T; Boekschoten, Mark V; Lute, Carolien; Hooiveld, Guido J; de Groot, Philip J; Morris, Tiffany J; Teschendorff, Andrew E; Butcher, Lee M; Beck, Stephan; Müller, Michael

    2014-06-01

    Aging is a progressive process that results in the accumulation of intra- and extracellular alterations that in turn contribute to a reduction in health. Age-related changes in DNA methylation have been reported before and may be responsible for aging-induced changes in gene expression, although a causal relationship has yet to be shown. Using genome-wide assays, we analyzed age-induced changes in DNA methylation and their effect on gene expression with and without transient induction with the synthetic transcription modulating agent WY14,643. To demonstrate feasibility of the approach, we isolated peripheral blood mononucleated cells (PBMCs) from five young and five old healthy male volunteers and cultured them with or without WY14,643. Infinium 450K BeadChip and Affymetrix Human Gene 1.1 ST expression array analysis revealed significant differential methylation of at least 5 % (ΔYO > 5 %) at 10,625 CpG sites between young and old subjects, but only a subset of the associated genes were also differentially expressed. Age-related differential methylation of previously reported epigenetic biomarkers of aging including ELOVL2, FHL2, PENK, and KLF14 was confirmed in our study, but these genes did not display an age-related change in gene expression in PBMCs. Bioinformatic analysis revealed that differentially methylated genes that lack an age-related expression change predominantly represent genes involved in carcinogenesis and developmental processes, and expression of most of these genes were silenced in PBMCs. No changes in DNA methylation were found in genes displaying transiently induced changes in gene expression. In conclusion, aging-induced differential methylation often targets developmental genes and occurs mostly without change in gene expression. PMID:24789080

  16. Evolutionary analysis of the jacalin-related lectin family genes in 11 fishes.

    PubMed

    Cao, Jun; Lv, Yueqing

    2016-09-01

    Jacalin-related lectins are a type of carbohydrate-binding proteins, which are distributed across a wide variety of organisms and involved in some important biological processes. The evolution of this gene family in fishes is unknown. Here, 47 putative jacalin genes in 11 fish species were identified and divided into 4 groups through phylogenetic analysis. Conserved gene organization and motif distribution existed in each group, suggesting their functional conservation. Some fishes have eleven jacalin genes, while others have only one or zero gene in their genomes, suggesting dynamic changes in the number of jacalin genes during the evolution of fishes. Intragenic recombination played a key role in the evolution of jacalin genes. Synteny analyses of jacalin genes in some fishes implied conserved and dynamic evolution characteristics of this gene family and related genome segments. Moreover, a few functional divergence sites were identified within each group pairs. Divergent expression profiles of the zebra fish jacalin genes were further investigated in different stresses. The results provided a foundation for exploring the characterization of the jacalin genes in fishes and will offer insights for additional functional studies. PMID:27514782

  17. An integrated database of wood-formation related genes in plants.

    PubMed

    Xu, Ting; Ma, Tao; Hu, Quanjun; Liu, Jianquan

    2015-06-16

    Wood, which consists mainly of plant cell walls, is an extremely important resource in daily lives. Genes whose products participate in the processes of cell wall and wood formation are therefore major subjects of plant science research. The Wood-Formation Related Genes database (WFRGdb, http://me.lzu.edu.cn/woodformation/) serves as a data resource center for genes involved in wood formation. To create this database, we collected plant genome data published in other online databases and predicted all cell wall and wood formation related genes using BLAST and HMMER. To date, 47 gene families and 33 transcription factors from 57 genomes (28 herbaceous, 22 woody and 7 non-vascular plants) have been covered and more than 122,000 genes have been checked and recorded. To provide easy access to these data, we have developed several search methods, which make it easy to download targeted genes or groups of genes free of charge in FASTA format. Sequence and phylogenetic analyses are also available online. WFRGdb brings together cell wall and wood formation related genes from all available plant genomes, and provides an integrative platform for gene inquiry, downloading and analysis. This database will therefore be extremely useful for those who focuses on cell wall and wood research.

  18. An integrated database of wood-formation related genes in plants

    PubMed Central

    Xu, Ting; Ma, Tao; Hu, Quanjun; Liu, Jianquan

    2015-01-01

    Wood, which consists mainly of plant cell walls, is an extremely important resource in daily lives. Genes whose products participate in the processes of cell wall and wood formation are therefore major subjects of plant science research. The Wood-Formation Related Genes database (WFRGdb, http://me.lzu.edu.cn/woodformation/) serves as a data resource center for genes involved in wood formation. To create this database, we collected plant genome data published in other online databases and predicted all cell wall and wood formation related genes using BLAST and HMMER. To date, 47 gene families and 33 transcription factors from 57 genomes (28 herbaceous, 22 woody and 7 non-vascular plants) have been covered and more than 122,000 genes have been checked and recorded. To provide easy access to these data, we have developed several search methods, which make it easy to download targeted genes or groups of genes free of charge in FASTA format. Sequence and phylogenetic analyses are also available online. WFRGdb brings together cell wall and wood formation related genes from all available plant genomes, and provides an integrative platform for gene inquiry, downloading and analysis. This database will therefore be extremely useful for those who focuses on cell wall and wood research. PMID:26078228

  19. Bovine gene polymorphisms related to fat deposition and meat tenderness

    PubMed Central

    2009-01-01

    Leptin, thyroglobulin and diacylglycerol O-acyltransferase play important roles in fat metabolism. Fat deposition has an influence on meat quality and consumers' choice. The aim of this study was to determine allele and genotype frequencies of polymorphisms of the bovine genes, which encode leptin (LEP), thyroglobulin (TG) and diacylglycerol O-acyltransferase (DGAT1). A further objective was to establish the effects of these polymorphisms on meat characteristics. We genotyped 147 animals belonging to the Nelore (Bos indicus), Canchim (5/8 Bos taurus + 3/8 Bos indicus), Rubia Gallega X Nelore (1/2 Bos taurus + 1/2 Bos indicus), Brangus Three-way cross (9/16 Bos taurus + 7/16 Bos indicus) and Braunvieh Three-way cross (3/4 Bos taurus + 1/4 Bos indicus) breeds. Backfat thickness, total lipids, marbling score, ribeye area and shear force were fitted, using the General Linear Model (GLM) procedure of the SAS software. The least square means of genotypes and genetic groups were compared using Tukey's test. Allele frequencies vary among the genetic groups, depending on Bos indicus versus Bos taurus influence. The LEP polymorphism segregates in pure Bos indicus Nelore animals, which is a new finding. The T allele of TG is fixed in Nelore, and DGAT1 segregates in all groups, but the frequency of allele A is lower in Nelore animals. The results showed no association between the genotypes and traits studied, but a genetic group effect on these traits was found. So, the genetic background remains relevant for fat deposition and meat tenderness, but the gene markers developed for Bos taurus may be insufficient for Bos indicus. PMID:21637649

  20. Antioxidant response and related gene expression in aged oat seed

    PubMed Central

    Kong, Lingqi; Huo, Heqiang; Mao, Peisheng

    2015-01-01

    To evaluate deterioration of oat seeds during storage, we analyzed oxygen radicals, antioxidant enzyme activity, proline content, and gene transcript levels in oat seeds with different moisture contents (MCs; 4, 16, and 28% w/w) during storage for 0, 6, and 12 months (CK, LT-6, and LT-12 treatments, respectively) at 4°C. The germination percentage decreased significantly with higher seed MCs and longer storage duration. The concentrations of superoxide radical and hydrogen peroxide increased with seed MC increasing. The activities of catalase (CAT), ascorbate peroxidase (APX), and superoxide dismutase (SOD) may have had a complementary or interacting role to scavenge reactive oxygen species. As the storage duration extended, the proline content decreased in seeds with 4 and 16% MC and increased in 28%. These findings suggest that proline played the main role in adaptation to oxidative stress in seeds with higher MC (28%), while antioxidant enzymes played the main role in seeds with lower MCs (4%, 16%). In the gene transcript analyses, SOD1 transcript levels were not consistent with total SOD activity. The transcript levels of APX1 and CAT1 showed similar trends to those of APX and CAT activity. The transcript levels of P5CS1, which encodes a proline biosynthetic enzyme, increased with seed MC increasing in CK. Compared with changing of proline content in seeds stored 12 months, PDH1 transcript levels showed the opposite trend and maintained the lower levels in seeds of 16 and 28% MCs. The transcript level of P5CS1 was significantly affected by MC, and PDH1 could improve stress resistance for seed aging and maintain seed vigor during long-term storage. PMID:25852711

  1. Bovine gene polymorphisms related to fat deposition and meat tenderness.

    PubMed

    Fortes, Marina R S; Curi, Rogério A; Chardulo, Luis Artur L; Silveira, Antonio C; Assumpção, Mayra E O D; Visintin, José Antonio; de Oliveira, Henrique N

    2009-01-01

    Leptin, thyroglobulin and diacylglycerol O-acyltransferase play important roles in fat metabolism. Fat deposition has an influence on meat quality and consumers' choice. The aim of this study was to determine allele and genotype frequencies of polymorphisms of the bovine genes, which encode leptin (LEP), thyroglobulin (TG) and diacylglycerol O-acyltransferase (DGAT1). A further objective was to establish the effects of these polymorphisms on meat characteristics. We genotyped 147 animals belonging to the Nelore (Bos indicus), Canchim (5/8 Bos taurus + 3/8 Bos indicus), Rubia Gallega X Nelore (1/2 Bos taurus + 1/2 Bos indicus), Brangus Three-way cross (9/16 Bos taurus + 7/16 Bos indicus) and Braunvieh Three-way cross (3/4 Bos taurus + 1/4 Bos indicus) breeds. Backfat thickness, total lipids, marbling score, ribeye area and shear force were fitted, using the General Linear Model (GLM) procedure of the SAS software. The least square means of genotypes and genetic groups were compared using Tukey's test. Allele frequencies vary among the genetic groups, depending on Bos indicus versus Bos taurus influence. The LEP polymorphism segregates in pure Bos indicus Nelore animals, which is a new finding. The T allele of TG is fixed in Nelore, and DGAT1 segregates in all groups, but the frequency of allele A is lower in Nelore animals. The results showed no association between the genotypes and traits studied, but a genetic group effect on these traits was found. So, the genetic background remains relevant for fat deposition and meat tenderness, but the gene markers developed for Bos taurus may be insufficient for Bos indicus.

  2. Bovine gene polymorphisms related to fat deposition and meat tenderness.

    PubMed

    Fortes, Marina R S; Curi, Rogério A; Chardulo, Luis Artur L; Silveira, Antonio C; Assumpção, Mayra E O D; Visintin, José Antonio; de Oliveira, Henrique N

    2009-01-01

    Leptin, thyroglobulin and diacylglycerol O-acyltransferase play important roles in fat metabolism. Fat deposition has an influence on meat quality and consumers' choice. The aim of this study was to determine allele and genotype frequencies of polymorphisms of the bovine genes, which encode leptin (LEP), thyroglobulin (TG) and diacylglycerol O-acyltransferase (DGAT1). A further objective was to establish the effects of these polymorphisms on meat characteristics. We genotyped 147 animals belonging to the Nelore (Bos indicus), Canchim (5/8 Bos taurus + 3/8 Bos indicus), Rubia Gallega X Nelore (1/2 Bos taurus + 1/2 Bos indicus), Brangus Three-way cross (9/16 Bos taurus + 7/16 Bos indicus) and Braunvieh Three-way cross (3/4 Bos taurus + 1/4 Bos indicus) breeds. Backfat thickness, total lipids, marbling score, ribeye area and shear force were fitted, using the General Linear Model (GLM) procedure of the SAS software. The least square means of genotypes and genetic groups were compared using Tukey's test. Allele frequencies vary among the genetic groups, depending on Bos indicus versus Bos taurus influence. The LEP polymorphism segregates in pure Bos indicus Nelore animals, which is a new finding. The T allele of TG is fixed in Nelore, and DGAT1 segregates in all groups, but the frequency of allele A is lower in Nelore animals. The results showed no association between the genotypes and traits studied, but a genetic group effect on these traits was found. So, the genetic background remains relevant for fat deposition and meat tenderness, but the gene markers developed for Bos taurus may be insufficient for Bos indicus. PMID:21637649

  3. Sugar regulation of harvest-related genes in asparagus.

    PubMed

    Davies, K M; Seelye, J F; Irving, D E; Borst, W M; Hurst, P L; King, G A

    1996-07-01

    The signals controlling the abundance of transcripts up-regulated (pTIP27, pTIP31, and pTIP32) or down-regulated (pTIP20 and pTIP21) after harvest in asparagus (Asparagus officinalis L.) spears were examined. pTIP27 and pTIP31 are known to encode asparagine synthetase (AS) and a beta-galactosidase (beta-gal) homolog, respectively. The nucleotide sequences of pTIP20, pTIP21, and pTIP32 were determined, and they encode histone 3, histone 2B, and an unknown product, respectively. Changes in respiration, soluble sugars, and abundance of the five mRNAs were similar in the tips stored as 30-mm lengths or as part of 180-mm spears. We previously hypothesized that sugars may regulate the level of AS transcripts in asparagus tissue. Asparagus cell cultures were used to test the role of sugar status may regulate the level of AS transcripts in asparagus tissue. Asparagus cell cultures were used to test the role of sugar status in regulating gene expression. Transcript abundance for AS, beta-gal, and pTIP32 was low in cells in sugar-containing medium but increased within 12 h after transferring cells to a sugar-free medium. Histone 3 and histone 2B transcripts were, in general, abundant in cells on sugar-containing medium but declined in abundance when transferred to sugar-free medium. When cells were returned to sugar-containing medium the abundance of transcripts for histone 3 and histone 2B increased, whereas that for AS, beta-gal, and pTIP32 decreased. Soluble sugar levels are known to decline rapidly in the tips of harvested spears. Metabolic regulation by sugar status may have a major influence on gene expression in asparagus spears and other tissue after harvest. PMID:8754687

  4. Sugar regulation of harvest-related genes in asparagus.

    PubMed Central

    Davies, K M; Seelye, J F; Irving, D E; Borst, W M; Hurst, P L; King, G A

    1996-01-01

    The signals controlling the abundance of transcripts up-regulated (pTIP27, pTIP31, and pTIP32) or down-regulated (pTIP20 and pTIP21) after harvest in asparagus (Asparagus officinalis L.) spears were examined. pTIP27 and pTIP31 are known to encode asparagine synthetase (AS) and a beta-galactosidase (beta-gal) homolog, respectively. The nucleotide sequences of pTIP20, pTIP21, and pTIP32 were determined, and they encode histone 3, histone 2B, and an unknown product, respectively. Changes in respiration, soluble sugars, and abundance of the five mRNAs were similar in the tips stored as 30-mm lengths or as part of 180-mm spears. We previously hypothesized that sugars may regulate the level of AS transcripts in asparagus tissue. Asparagus cell cultures were used to test the role of sugar status may regulate the level of AS transcripts in asparagus tissue. Asparagus cell cultures were used to test the role of sugar status in regulating gene expression. Transcript abundance for AS, beta-gal, and pTIP32 was low in cells in sugar-containing medium but increased within 12 h after transferring cells to a sugar-free medium. Histone 3 and histone 2B transcripts were, in general, abundant in cells on sugar-containing medium but declined in abundance when transferred to sugar-free medium. When cells were returned to sugar-containing medium the abundance of transcripts for histone 3 and histone 2B increased, whereas that for AS, beta-gal, and pTIP32 decreased. Soluble sugar levels are known to decline rapidly in the tips of harvested spears. Metabolic regulation by sugar status may have a major influence on gene expression in asparagus spears and other tissue after harvest. PMID:8754687

  5. Discovery of New Candidate Genes Related to Brain Development Using Protein Interaction Information

    PubMed Central

    Chen, Lei; Chu, Chen; Kong, Xiangyin; Huang, Tao; Cai, Yu-Dong

    2015-01-01

    Human brain development is a dramatic process composed of a series of complex and fine-tuned spatiotemporal gene expressions. A good comprehension of this process can assist us in developing the potential of our brain. However, we have only limited knowledge about the genes and gene functions that are involved in this biological process. Therefore, a substantial demand remains to discover new brain development-related genes and identify their biological functions. In this study, we aimed to discover new brain-development related genes by building a computational method. We referred to a series of computational methods used to discover new disease-related genes and developed a similar method. In this method, the shortest path algorithm was executed on a weighted graph that was constructed using protein-protein interactions. New candidate genes fell on at least one of the shortest paths connecting two known genes that are related to brain development. A randomization test was then adopted to filter positive discoveries. Of the final identified genes, several have been reported to be associated with brain development, indicating the effectiveness of the method, whereas several of the others may have potential roles in brain development. PMID:25635857

  6. Prediction of nitrogen metabolism-related genes in Anabaena by kernel-based network analysis.

    PubMed

    Okamoto, Shinobu; Yamanishi, Yoshihiro; Ehira, Shigeki; Kawashima, Shuichi; Tonomura, Koichiro; Kanehisa, Minoru

    2007-03-01

    Prediction of molecular interaction networks from large-scale datasets in genomics and other omics experiments is an important task in terms of both developing bioinformatics methods and solving biological problems. We have applied a kernel-based network inference method for extracting functionally related genes to the response of nitrogen deprivation in cyanobacteria Anabaena sp. PCC 7120 integrating three heterogeneous datasets: microarray data, phylogenetic profiles, and gene orders on the chromosome. We obtained 1348 predicted genes that are somehow related to known genes in the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. While this dataset contained previously known genes related to the nitrogen deprivation condition, it also contained additional genes. Thus, we attempted to select any relevant genes using the constraints of Pfam domains and NtcA-binding sites. We found candidates of nitrogen metabolism-related genes, which are depicted as extensions of existing KEGG pathways. The prediction of functional relationships between proteins rather than functions of individual proteins will thus assist the discovery from the large-scale datasets.

  7. Genome-Wide Comparative Analysis of Flowering-Related Genes in Arabidopsis, Wheat, and Barley

    PubMed Central

    Peng, Fred Y.; Hu, Zhiqiu; Yang, Rong-Cai

    2015-01-01

    Early flowering is an important trait influencing grain yield and quality in wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) in short-season cropping regions. However, due to large and complex genomes of these species, direct identification of flowering genes and their molecular characterization remain challenging. Here, we used a bioinformatic approach to predict flowering-related genes in wheat and barley from 190 known Arabidopsis (Arabidopsis thaliana (L.) Heynh.) flowering genes. We identified 900 and 275 putative orthologs in wheat and barley, respectively. The annotated flowering-related genes were clustered into 144 orthologous groups with one-to-one, one-to-many, many-to-one, and many-to-many orthology relationships. Our approach was further validated by domain and phylogenetic analyses of flowering-related proteins and comparative analysis of publicly available microarray data sets for in silico expression profiling of flowering-related genes in 13 different developmental stages of wheat and barley. These further analyses showed that orthologous gene pairs in three critical flowering gene families (PEBP, MADS, and BBX) exhibited similar expression patterns among 13 developmental stages in wheat and barley, suggesting similar functions among the orthologous genes with sequence and expression similarities. The predicted candidate flowering genes can be confirmed and incorporated into molecular breeding for early flowering wheat and barley in short-season cropping regions. PMID:26435710

  8. Recombination between elongation factor 1α genes from distantly related archaeal lineages

    PubMed Central

    Inagaki, Yuji; Susko, Edward; Roger, Andrew J.

    2006-01-01

    Homologous recombination (HR) and lateral gene transfer are major processes in genome evolution. The combination of the two processes, HR between genes in different species, has been documented but is thought to be restricted to very similar sequences in relatively closely related organisms. Here we report two cases of interspecific HR in the gene encoding the core translational protein translation elongation factor 1α (EF-1α) between distantly related archaeal groups. Maximum-likelihood sliding window analyses indicate that a fragment of the EF-1α gene from the archaeal lineage represented by Methanopyrus kandleri was recombined into the orthologous gene in a common ancestor of the Thermococcales. A second recombination event appears to have occurred between the EF-1α gene of the genus Methanothermobacter and its ortholog in a common ancestor of the Methanosarcinales, a distantly related euryarchaeal lineage. These findings suggest that HR occurs across a much larger evolutionary distance than generally accepted and affects highly conserved essential “informational” genes. Although difficult to detect by standard whole-gene phylogenetic analyses, interspecific HR in highly conserved genes may occur at an appreciable frequency, potentially confounding deep phylogenetic inference and hypothesis testing. PMID:16537397

  9. Myelination-related genes are associated with decreased white matter integrity in schizophrenia.

    PubMed

    Chavarria-Siles, Ivan; White, Tonya; de Leeuw, Christiaan; Goudriaan, Andrea; Lips, Esther; Ehrlich, Stefan; Turner, Jessica A; Calhoun, Vince D; Gollub, Randy L; Magnotta, Vincent A; Ho, Beng-Choon; Smit, August B; Verheijen, Mark H G; Posthuma, Danielle

    2016-03-01

    Disruptions in white matter (WM) tract structures have been implicated consistently in the pathophysiology of schizophrenia. Global WM integrity--as measured by fractional anisotropy (FA)--is highly heritable and may provide a good endophenotype for genetic studies of schizophrenia. WM abnormalities in schizophrenia are not localized to one specific brain region but instead reflect global low-level decreases in FA coupled with focal abnormalities. In this study, we sought to investigate whether functional gene sets associated with schizophrenia are also associated with WM integrity. We analyzed FA and genetic data from the Mind Research Network Clinical Imaging Consortium to study the effect of multiple oligodendrocyte gene sets on schizophrenia and WM integrity using a functional gene set analysis in 77 subjects with schizophrenia and 104 healthy controls. We found that a gene set involved in myelination was significantly associated with schizophrenia and FA. This gene set includes 17 genes that are expressed in oligodendrocytes and one neuronal gene (NRG1) that is known to regulate myelination. None of the genes within the gene set were associated with schizophrenia or FA individually, suggesting that no single gene was driving the association of the gene set. Our findings support the hypothesis that multiple genetic variants in myelination-related genes contribute to the observed correlation between schizophrenia and decreased WM integrity as measured by FA.

  10. Unpredictable neonatal stress enhances adult anxiety and alters amygdala gene expression related to serotonin and GABA

    PubMed Central

    Sarro, Emma C; Sullivan, Regina M; Barr, Gordon

    2014-01-01

    Anxiety-related disorders are among the most common psychiatric illnesses, thought to have both genetic and environmental causes. Early-life trauma, such as abuse from a caregiver, can be predictable or unpredictable, each resulting in increased prevalence and severity of a unique set of disorders. In this study, we examined the influence of early unpredictable trauma on both the behavioral expression of adult anxiety and gene expression within the amygdala. Neonatal rats were exposed to unpaired odor-shock conditioning for 5 days, which produces deficits in adult behavior and amygdala dysfunction. In adulthood, we used the Light/Dark box test to measure anxiety-related behaviors, measuring the latency to enter the lit area and quantified urination and defecation. The amygdala was then dissected and a microarray analysis was performed to examine changes in gene expression. Animals that had received early unpredictable trauma displayed significantly longer latencies to enter the lit area and more defecation and urination. The microarray analysis revealed over-represented genes related to learning and memory, synaptic transmission and trans-membrane transport. Gene ontology and pathway analysis identified highly represented disease states related to anxiety phenotypes, including social anxiety, obsessive-compulsive disorders, PTSD and bipolar disorder. Addiction related genes were also overrepresented in this analysis. Unpredictable shock during early development increased anxiety-like behaviors in adulthood with concomitant changes in genes related to neurotransmission, resulting in gene expression patterns similar to anxiety-related psychiatric disorders. PMID:24240029

  11. Comparison of Envelope-Related Genes in Unicellular and Filamentous Cyanobacteria

    PubMed Central

    Yang, Yu; Qin, Song; Zhao, Fangqing; Chi, Xiaoyuan; Zhang, Xiaowen

    2007-01-01

    To elucidate the evolution of cyanobacterial envelopes and the relation between gene content and environmental adaptation, cell envelope structures and components of unicellular and filamentous cyanobacteria were analyzed in comparative genomics. Hundreds of envelope biogenesis genes were divided into 5 major groups and annotated according to their conserved domains and phylogenetic profiles. Compared to unicellular species, the gene numbers of filamentous cyanobacteria expanded due to genome enlargement effect, but only few gene families amplified disproportionately, such as those encoding waaG and glycosyl transferase 2. Comparison of envelope genes among various species suggested that the significant variance of certain cyanobacterial envelope biogenesis genes should be the response to their environmental adaptation, which might be also related to the emergence of filamentous shapes with some new functions. PMID:18253473

  12. Identification of Immunity Related Genes to Study the Physalis peruviana – Fusarium oxysporum Pathosystem

    PubMed Central

    Enciso-Rodríguez, Felix E.; González, Carolina; Rodríguez, Edwin A.; López, Camilo E.; Landsman, David; Barrero, Luz Stella; Mariño-Ramírez, Leonardo

    2013-01-01

    The Cape gooseberry (Physalisperuviana L) is an Andean exotic fruit with high nutritional value and appealing medicinal properties. However, its cultivation faces important phytosanitary problems mainly due to pathogens like Fusarium oxysporum, Cercosporaphysalidis and Alternaria spp. Here we used the Cape gooseberry foliar transcriptome to search for proteins that encode conserved domains related to plant immunity including: NBS (Nucleotide Binding Site), CC (Coiled-Coil), TIR (Toll/Interleukin-1 Receptor). We identified 74 immunity related gene candidates in P. peruviana which have the typical resistance gene (R-gene) architecture, 17 Receptor like kinase (RLKs) candidates related to PAMP-Triggered Immunity (PTI), eight (TIR-NBS-LRR, or TNL) and nine (CC–NBS-LRR, or CNL) candidates related to Effector-Triggered Immunity (ETI) genes among others. These candidate genes were categorized by molecular function (98%), biological process (85%) and cellular component (79%) using gene ontology. Some of the most interesting predicted roles were those associated with binding and transferase activity. We designed 94 primers pairs from the 74 immunity-related genes (IRGs) to amplify the corresponding genomic regions on six genotypes that included resistant and susceptible materials. From these, we selected 17 single band amplicons and sequenced them in 14 F. oxysporum resistant and susceptible genotypes. Sequence polymorphisms were analyzed through preliminary candidate gene association, which allowed the detection of one SNP at the PpIRG-63 marker revealing a nonsynonymous mutation in the predicted LRR domain suggesting functional roles for resistance. PMID:23844210

  13. Gene Expression in Relation to Exhaled Nitric Oxide Identifies Novel Asthma Phenotypes with Unique Biomolecular Pathways

    PubMed Central

    Modena, Brian D.; Tedrow, John R.; Milosevic, Jadranka; Bleecker, Eugene R.; Meyers, Deborah A.; Wu, Wei; Bar-Joseph, Ziv; Erzurum, Serpil C.; Gaston, Benjamin M.; Busse, William W.; Jarjour, Nizar N.; Kaminski, Naftali

    2014-01-01

    Rationale Although asthma is recognized as a heterogeneous disease associated with clinical phenotypes, the molecular basis of these phenotypes remains poorly understood. Although genomic studies have successfully broadened our understanding in diseases such as cancer, they have not been widely used in asthma studies. Objectives To link gene expression patterns to clinical asthma phenotypes. Methods We used a microarray platform to analyze bronchial airway epithelial cell gene expression in relation to the asthma biomarker fractional exhaled nitric oxide (FeNO) in 155 subjects with asthma and healthy control subjects from the Severe Asthma Research Program (SARP). Measurements and Main Results We first identified a diverse set of 549 genes whose expression correlated with FeNO. We used k-means to cluster the patient samples according to the expression of these genes, identifying five asthma clusters/phenotypes with distinct clinical, physiological, cellular, and gene transcription characteristics—termed “subject clusters” (SCs). To then investigate differences in gene expression between SCs, a total of 1,384 genes were identified that highly differentiated the SCs at an unadjusted P value < 10−6. Hierarchical clustering of these 1,384 genes identified nine gene clusters or “biclusters,” whose coexpression suggested biological characteristics unique to each SC. Although genes related to type 2 inflammation were present, novel pathways, including those related to neuronal function, WNT pathways, and actin cytoskeleton, were noted. Conclusions These findings show that bronchial epithelial cell gene expression, as related to the asthma biomarker FeNO, can identify distinct asthma phenotypes, while also suggesting the presence of underlying novel gene pathways relevant to these phenotypes. PMID:25338189

  14. Identifying Gastric Cancer Related Genes Using the Shortest Path Algorithm and Protein-Protein Interaction Network

    PubMed Central

    Shi, Ying; Li, Li-Peng; Ren, Hui

    2014-01-01

    Gastric cancer, as one of the leading causes of cancer related deaths worldwide, causes about 800,000 deaths per year. Up to now, the mechanism underlying this disease is still not totally uncovered. Identification of related genes of this disease is an important step which can help to understand the mechanism underlying this disease, thereby designing effective treatments. In this study, some novel gastric cancer related genes were discovered based on the knowledge of known gastric cancer related ones. These genes were searched by applying the shortest path algorithm in protein-protein interaction network. The analysis results suggest that some of them are indeed involved in the biological process of gastric cancer, which indicates that they are the actual gastric cancer related genes with high probability. It is hopeful that the findings in this study may help promote the study of this disease and the methods can provide new insights to study various diseases. PMID:24729971

  15. Identification of brassinosteroid-related genes by means of transcript co-response analyses

    PubMed Central

    Lisso, Janina; Steinhauser, Dirk; Altmann, Thomas; Kopka, Joachim; Müssig, Carsten

    2005-01-01

    The comprehensive systems-biology database (CSB.DB) was used to reveal brassinosteroid (BR)-related genes from expression profiles based on co-response analyses. Genes exhibiting simultaneous changes in transcript levels are candidates of common transcriptional regulation. Combining numerous different experiments in data matrices allows ruling out outliers and conditional changes of transcript levels. CSB.DB was queried for transcriptional co-responses with the BR-signalling components BRI1 and BAK1: 301 out of 9694 genes represented in the nasc0271 database showed co-responses with both genes. As expected, these genes comprised pathway-involved genes (e.g. 72 BR-induced genes), because the BRI1 and BAK1 proteins are required for BR-responses. But transcript co-response takes the analysis a step further compared with direct approaches because BR-related non BR-responsive genes were identified. Insights into networks and the functional context of genes are provided, because factors determining expression patterns are reflected in correlations. Our findings demonstrate that transcript co-response analysis presents a valuable resource to uncover common regulatory patterns of genes. Different data matrices in CSB.DB allow examination of specific biological questions. All matrices are publicly available through CSB.DB. This work presents one possible roadmap to use the CSB.DB resources. PMID:15891113

  16. Identification and characterization of stress resistance related genes of Brassica rapa.

    PubMed

    Ahmed, Nasar Uddin; Park, Jong-In; Jung, Hee-Jeong; Seo, Mi-Suk; Kumar, Thamilarasan Senthil; Lee, In-Ho; Nou, Ill-Sup

    2012-05-01

    Two biotic stress resistance related genes from the full-length cDNA library of Brassica rapa cv. Osome were identified from EST analysis and determined to be pathogenesis-related (PR) 12 Brassica defensin-like family protein (BrDLFP) and PR-10 Brassica Betv1 allergen family protein (BrBetv1AFP) after sequence analysis and homology study with other stress resistance related same family genes. In the expression analysis, both genes expressed in different organs and during all developmental growth stages in healthy plants. Expression of BrDLFP significantly increased and BrBetv1AFP gradually decreased after infection with Pectobacterium carotovorum subsp. carotovorum in Chinese cabbage. Expression of these two genes significantly changed after cold, salt, drought and ABA stress treatments. These two PR genes may therefore be involved in the plant resistance against biotic and abiotic stresses.

  17. Analysis of vascular endothelial dysfunction genes and related pathways in obesity through systematic bioinformatics.

    PubMed

    Zhang, Hui; Wang, Jing; Sun, Ling; Xu, Qiuqin; Hou, Miao; Ding, Yueyue; Huang, Jie; Chen, Ye; Cao, Lei; Zhang, Jianmin; Qian, Weiguo; Lv, Haitao

    2015-01-01

    Obesity has become an increasingly serious health problem and popular research topic. It is associated with many diseases, especially cardiovascular disease (CVD)-related endothelial dysfunction. This study analyzed genes related to endothelial dysfunction and obesity and then summarized their most significant signaling pathways. Genes related to vascular endothelial dysfunction and obesity were extracted from a PubMed database, and analyzed by STRING, DAVID, and Gene-Go Meta-Core software. 142 genes associated with obesity were found to play a role in endothelial dysfunction in PubMed. A significant pathway (Angiotensin system maturation in protein folding and maturation) associated with obesity and endothelial dysfunction was explored. The genes and the pathway explored may play an important role in obesity. Further studies about preventing vascular endothelial dysfunction obesity should be conducted through targeting these loci and pathways.

  18. Identification and characterization of stress resistance related genes of Brassica rapa.

    PubMed

    Ahmed, Nasar Uddin; Park, Jong-In; Jung, Hee-Jeong; Seo, Mi-Suk; Kumar, Thamilarasan Senthil; Lee, In-Ho; Nou, Ill-Sup

    2012-05-01

    Two biotic stress resistance related genes from the full-length cDNA library of Brassica rapa cv. Osome were identified from EST analysis and determined to be pathogenesis-related (PR) 12 Brassica defensin-like family protein (BrDLFP) and PR-10 Brassica Betv1 allergen family protein (BrBetv1AFP) after sequence analysis and homology study with other stress resistance related same family genes. In the expression analysis, both genes expressed in different organs and during all developmental growth stages in healthy plants. Expression of BrDLFP significantly increased and BrBetv1AFP gradually decreased after infection with Pectobacterium carotovorum subsp. carotovorum in Chinese cabbage. Expression of these two genes significantly changed after cold, salt, drought and ABA stress treatments. These two PR genes may therefore be involved in the plant resistance against biotic and abiotic stresses. PMID:22286206

  19. Photoelectrochemical H2 Evolution with a Hydrogenase Immobilized on a TiO2 -Protected Silicon Electrode.

    PubMed

    Lee, Chong-Yong; Park, Hyun S; Fontecilla-Camps, Juan C; Reisner, Erwin

    2016-05-10

    The combination of enzymes with semiconductors enables the photoelectrochemical characterization of electron-transfer processes at highly active and well-defined catalytic sites on a light-harvesting electrode surface. Herein, we report the integration of a hydrogenase on a TiO2 -coated p-Si photocathode for the photo-reduction of protons to H2 . The immobilized hydrogenase exhibits activity on Si attributable to a bifunctional TiO2 layer, which protects the Si electrode from oxidation and acts as a biocompatible support layer for the productive adsorption of the enzyme. The p-Si|TiO2 |hydrogenase photocathode displays visible-light driven production of H2 at an energy-storing, positive electrochemical potential and an essentially quantitative faradaic efficiency. We have thus established a widely applicable platform to wire redox enzymes in an active configuration on a p-type semiconductor photocathode through the engineering of the enzyme-materials interface. PMID:27061334

  20. "Two-step" chronoamperometric method for studying the anaerobic inactivation of an oxygen tolerant NiFe hydrogenase.

    PubMed

    Fourmond, Vincent; Infossi, Pascale; Giudici-Orticoni, Marie-Thérèse; Bertrand, Patrick; Léger, Christophe

    2010-04-01

    Hydrogenases catalyze the oxidation and production of H(2). The fact that they could be used in biotechnological devices if they resisted inhibition by O(2) motivates the current research on their inactivation mechanism. Direct electrochemistry has been thoroughly used in this respect but often in a qualitative manner. We propose a new and precise chronoamperometric method for studying the anaerobic inactivation mechanism of hydrogenase, which we apply to the oxygen-tolerant NiFe enzyme from Aquifex aeolicus . We demonstrate that the voltammetric data cannot be used for measuring the reduction potential of the so-called NiB inactive state, even in the small scan rate limit. We show that the inactivation mechanism proposed for standard (oxygen-sensitive) NiFe hydrogenases does not apply in the case of the enzyme from A. aeolicus . In particular, the activation and inactivation reactions cannot follow the same reaction pathway.

  1. Role of the Hya Hydrogenase in Recycling of Anaerobically Produced H2 in Salmonella enterica Serovar Typhimurium▿

    PubMed Central

    Zbell, Andrea L.; Maier, Robert J.

    2009-01-01

    Double and triple uptake-type hydrogenase mutants were used to determine which hydrogenase recycles fermentatively produced hydrogen. The Δhyb Δhya and Δhyd Δhya double mutants evolved H2 at rates similar to that of the triple mutant strain, so Hya alone oxidizes the bulk of H2 produced during fermentation. When only Hya was present, no hydrogen production was observed in nutrient-limited medium. H2 uptake assays showed that Hya can oxidize both exogenously added H2 and formate hydrogen lyase-evolved H2 anaerobically. Even after anaerobic growth, all three uptake-type hydrogenases could function in the presence of oxygen, including using O2 as a terminal acceptor. PMID:19114523

  2. Utilization of digital differential display to identify differentially expressed genes related to rumen development.

    PubMed

    Kato, Daichi; Suzuki, Yutaka; Haga, Satoshi; So, KyoungHa; Yamauchi, Eri; Nakano, Miwa; Ishizaki, Hiroshi; Choi, Kichoon; Katoh, Kazuo; Roh, Sang-Gun

    2016-04-01

    This study aimed to identify the genes associated with the development of the rumen epithelium by screening for candidate genes by digital differential display (DDD) in silico. Using DDD in NCBI's UniGene database, expressed sequence tag (EST)-based gene expression profiles were analyzed in rumen, reticulum, omasum, abomasum and other tissues in cattle. One hundred and ten candidate genes with high expression in the rumen were derived from a library of all tissues. The expression levels of 11 genes in all candidate genes were analyzed in the rumen, reticulum, omasum and abomasum of nine Japanese Black male calves (5-week-old pre-weaning: n = 3; 15-week-old weaned calves: n = 6). Among the 11 genes, only 3-hydroxy-3-methylglutaryl-CoA synthase 2 (HMGCS2), aldo-keto reductase family 1, member C1-like (AKR1C1), and fatty acid binding protein 3 (FABP3) showed significant changes in the levels of gene expression in the rumen between the pre- and post-weaning of calves. These results indicate that DDD analysis in silico can be useful for screening candidate genes related to rumen development, and that the changes in expression levels of three genes in the rumen may have been caused by weaning, aging or both.

  3. Comparative sequence and expression analysis of tapetum specific male sterility related genes in Medicago truncatula.

    PubMed

    Shao, L H; Zheng, X W; Yi, D X; Li, C

    2016-01-01

    Heterosis, or enhancement through outbreeding, is one of the most promising approaches for increasing crop yield. Male sterility (MS), which promotes heterosis, has been widely applied in hybrid crop production. Medicago truncatula is a model legume species and is closely related to M. sativa, an important legume forage plant. Although the molecular mechanisms of MS in M. truncatula and M. sativa remain unclear, several studies of MS have been conducted in Arabidopsis thaliana. Previous research has shown that MS is associated with the destruction of tapetal cell layers. Disruption of tapetum developmental processes may result in pollen abortion. In an effort to identify genes useful for breeding in M. sativa, we identified MS related genes in M. truncatula using BLAST and homology to A. thaliana genes. In this study, we identified 63 tapetum specific male sterility (TSMS) related genes. The length of TSMS genes varied from 225 to 3747 bp. We identified 15 conserved domains and 8 cis-elements associated with TSMS related genes. Analysis of the phylogenetic relationships among these genes allowed them to be classified into three groups, MtTsms A, MtTsms B, and MtTsms C. Expression analyses revealed that these genes may be involved in developmental processes and response to abiotic stress. PMID:27421020

  4. Measured Gene-by-Environment Interaction in Relation to Attention-Deficit/Hyperactivity Disorder

    ERIC Educational Resources Information Center

    Nigg, Joel; Nikolas, Molly; Burt, S. Alexandra

    2010-01-01

    Objective: To summarize and evaluate the state of knowledge regarding the role of measured gene-by-environment interactions in relation to attention-deficit/hyperactivity disorder. Method: A selective review of methodologic issues was followed by a systematic search for relevant articles on measured gene-by-environment interactions; the search…

  5. Centrin protein and genes in Trichomonas vaginalis and close relatives.

    PubMed

    Brugerolle, G; Bricheux, G; Coffe, G

    2000-01-01

    Anti-centrin monoclonal antibodies 20H5 and 11B2 produced against Clamydomononas centrin decorated the group of basal bodies as well as very closely attached structures in all trichomonads studied and in the devescovinids Foaina and Devescovina. Moreover, these antibodies decorated the undulating membrane in Trichomonas vaginalis, Trichomitus batrachorum, and Tritrichomonas foetus, and the cresta in Foaina. Centrin was not demonstrated in the dividing spindle and paradesmosis. Immunogold labeling, both in pre- and post-embedding, confirmed that centrin is associated with the basal body cylinder and is a component of the nine anchoring arms between the terminal plate of flagellar bases and the plasma-membrane. Centrin is also associated with the hook-shaped fibers attached to basal bodies (F1, F3), the X-fiber, and along sigmoid fibers (F2) at the pelta-axostyle junction, which is the microtubule organizing center for pelta-axostyle microtubules. There was no labeling on the striated costa and parabasal fibers nor on microtubular pelta-axostyle, but the fibrous structure inside the undulating membrane was labeled in T. vaginalis. Two proteins of 22-20 kDa corresponding to the centrin molecular mass were recognized by immunoblotting using these antibodies in the three trichomonad species examined. By screening a T. vaginalis cDNA library with 20H5 antibody, two genes encoding identical protein sequences were found. The sequence comprises the 4 typical EF-hand Ca++-binding domains present in every known centrin. Trichomonad centrin is closer to the green algal cluster (70% identity) than to the yeast Cdc31 cluster (55% identity) or the Alveolata cluster (46% identity). PMID:10750840

  6. Expression profiles of DNA repair-related genes in rat target organs under subchronic cadmium exposure.

    PubMed

    Lei, Y X; Lu, Q; Shao, C; He, C C; Lei, Z N; Lian, Y Y

    2015-01-01

    We aimed to evaluate the toxicity of long-term exposure to different cadmium (Cd) doses in rats and expression profiles of DNA repair-related genes. The model rats were exposed to different concentrations of CdCl2 for 3 months, and 5 DNA repair-related genes - hMSH2, MLH1, XRCC1, hOGG1, ERCC1 - were cloned in different tissues, including the liver, kidney, heart, and lung. Accumulated amounts of Cd were detected in the tissues. Gene and protein detections were conducted via fluorescence quantitative real-time polymerase chain reaction and Western blotting, respectively. Methylated sequences of the 5 DNA repair-related gene promoters were used to investigate whether the low expression levels of the genes were related to methylation of the promoter. In the Cd-exposed group, 3 DNA repair genes (i.e., XRCC1, hOGG1, and ERCC1) significantly decreased in the rat liver, kidney, heart, and lung according to the β-actin internal standard (P < 0.01). Western blotting indicated the same trend for the different tissues. Each of the DNA repair genes had special characteristics; for example, hOGG1 gene expression decreased by 75% in the kidney, and XRCC1 gene expression decreased by 5% in the liver and heart when compared to the control group (P < 0.01). A negative correlation between the DNA repair gene expression levels and the cumulative levels of Cd was also suggested by malignancy pathology. The expression levels of 3 DNA repair genes (i.e., ERCC1, XRCC1, and hOGG1) played an important role in the rat response to Cd exposure but not DNA methylated protection. PMID:25729986

  7. Association analysis of dyslipidemia-related genes in diabetic nephropathy.

    PubMed

    McKay, Gareth J; Savage, David A; Patterson, Christopher C; Lewis, Gareth; McKnight, Amy Jayne; Maxwell, Alexander P

    2013-01-01

    Type 1 diabetes (T1D) increases risk of the development of microvascular complications and cardiovascular disease (CVD). Dyslipidemia is a common risk factor in the pathogenesis of both CVD and diabetic nephropathy (DN), with CVD identified as the primary cause of death in patients with DN. In light of this commonality, we assessed single nucleotide polymorphisms (SNPs) in thirty-seven key genetic loci previously associated with dyslipidemia in a T1D cohort using a case-control design. SNPs (n = 53) were genotyped using Sequenom in 1467 individuals with T1D (718 cases with proteinuric nephropathy and 749 controls without nephropathy i.e. normal albumin excretion). Cases and controls were white and recruited from the UK and Ireland. Association analyses were performed using PLINK to compare allele frequencies in cases and controls. In a sensitivity analysis, samples from control individuals with reduced renal function (estimated glomerular filtration rate<60 ml/min/1.73 m(2)) were excluded. Correction for multiple testing was performed by permutation testing. A total of 1394 samples passed quality control filters. Following regression analysis adjusted by collection center, gender, duration of diabetes, and average HbA1c, two SNPs were significantly associated with DN. rs4420638 in the APOC1 region (odds ratio [OR] = 1.51; confidence intervals [CI]: 1.19-1.91; P = 0.001) and rs1532624 in CETP (OR = 0.82; CI: 0.69-0.99; P = 0.034); rs4420638 was also significantly associated in a sensitivity analysis (P = 0.016) together with rs7679 (P = 0.027). However, no association was significant following correction for multiple testing. Subgroup analysis of end-stage renal disease status failed to reveal any association. Our results suggest common variants associated with dyslipidemia are not strongly associated with DN in T1D among white individuals. Our findings, cannot entirely exclude these key genes which are central to the process of dyslipidemia, from involvement in DN

  8. Guiding Principles of Hydrogenase Catalysis Instigated and Clarified by Protein Film Electrochemistry.

    PubMed

    Armstrong, Fraser A; Evans, Rhiannon M; Hexter, Suzannah V; Murphy, Bonnie J; Roessler, Maxie M; Wulff, Philip

    2016-05-17

    Protein film electrochemistry (PFE) is providing cutting-edge insight into the chemical principles underpinning biological hydrogen. Attached to an electrode, many enzymes exhibit "reversible" electrocatalytic behavior, meaning that a catalyzed redox reaction appears reversible or quasi-reversible when viewed by cyclic voltammetry. This efficiency is most relevant for enzymes that are inspiring advances in renewable energy, such as hydrogen-activating and CO2-reducing enzymes. Exploiting the rich repertoire of available instrumental methods, PFE experiments yield both a general snapshot and fine detail, all from tiny samples of enzyme. The dynamic electrochemical investigations blaze new trails and add exquisite detail to the information gained from structural and spectroscopic studies. This Account describes recent investigations of hydrogenases carried out in Oxford, including ideas initiated with PFE and followed through with complementary techniques, all contributing to an eventual complete picture of fast and efficient H2 activation without Pt. By immobilization of an enzyme on an electrode, catalytic electron flow and the chemistry controlling it can be addressed at the touch of a button. The buried nature of the active site means that structures that have been determined by crystallography or spectroscopy are likely to be protected, retained, and fully relevant in a PFE experiment. An electrocatalysis model formulated for the PFE of immobilized enzymes predicts interesting behavior and gives insight into why some hydrogenases are H2 producers and others are H2 oxidizers. Immobilization also allows for easy addition and removal of inhibitors along with precise potential control, one interesting outcome being that formaldehyde forms a reversible complex with reduced [FeFe]-hydrogenases, thereby providing insight into the order of electron and proton transfers. Experiments on O2-tolerant [NiFe]-hydrogenases show that O2 behaves like a reversible inhibitor: it

  9. Genes related to xylose fermentation and methods of using same for enhanced biofuel production

    SciTech Connect

    Wohlbach, Dana J.; Gasch, Audrey P.

    2014-08-05

    The present invention provides isolated gene sequences involved in xylose fermentation and related recombinant yeast which are useful in methods of enhanced biofuel production, particularly ethanol production. Methods of bioengineering recombinant yeast useful for biofuel production are also provided.

  10. Genes related to xylose fermentation and methods of using same for enhanced biofuel production

    SciTech Connect

    Wohlbach, Dana J.; Gasch, Audrey P.

    2015-09-29

    The present invention provides isolated gene sequences involved in xylose fermentation and related recombinant yeast which are useful in methods of enhanced biofuel production, particularly ethanol production. Methods of bioengineering recombinant yeast useful for biofuel production are also provided.

  11. Activation of multiple mitogen-activated protein kinases by recombinant calcitonin gene-related peptide receptor.

    PubMed

    Parameswaran, N; Disa, J; Spielman, W S; Brooks, D P; Nambi, P; Aiyar, N

    2000-02-18

    Calcitonin gene-related peptide is a 37-amino-acid neuropeptide and a potent vasodilator. Although calcitonin gene-related peptide has been shown to have a number of effects in a variety of systems, the mechanisms of action and the intracellular signaling pathways, especially the regulation of mitogen-activated protien kinase (MAPK) pathway, is not known. In the present study we investigated the role of calcitonin gene-related peptide in the regulation of MAPKs in human embryonic kidney (HEK) 293 cells stably transfected with a recombinant porcine calcitonin gene-related peptide-1 receptor. Calcitonin gene-related peptide caused a significant dose-dependent increase in cAMP response and the effect was inhibited by calcitonin gene-related peptide(8-37), the calcitonin gene-related peptide-receptor antagonist. Calcitonin gene-related peptide also caused a time- and concentration-dependent increase in extracellular signal-regulated kinase (ERK) and P38 mitogen-activated protein kinase (P38 MAPK) activities, with apparently no significant change in cjun-N-terminal kinase (JNK) activity. Forskolin, a direct activator of adenylyl cyclase also stimulated ERK and P38 activities in these cells suggesting the invovement of cAMP in this process. Calcitonin gene-related peptide-stimulated ERK and P38 MAPK activities were inhibited significantly by calcitonin gene-related peptide receptor antagonist, calcitonin gene-related peptide-(8-37) suggesting the involvement of calcitonin gene-related peptide-1 receptor. Preincubation of the cells with the cAMP-dependent protein kinase inhibitor, H89 [¿N-[2-((p-bromocinnamyl)amino)ethyl]-5-isoquinolinesulfonamide, hydrochloride¿] inhibited calcitonin gene-related peptide-mediated activation of ERK and p38 kinases. On the other hand, preincubation of the cells with wortmannin ¿[1S-(1alpha,6balpha,9abeta,11alpha, 11bbeta)]-11-(acetyloxy)-1,6b,7,8,9a,10,11, 11b-octahydro-1-(methoxymethyl)-9a,11b-dimethyl-3H-furo[4,3, 2-de]indeno[4,5-h]-2

  12. AGE-RELATED GENE EXPRESSION CHANGES IN HUMAN SKIN FIBROBLASTS INDUCED BY MMS

    EPA Science Inventory

    Age-Related Gene Expression Changes In Human Skin Fibroblasts Induced By methyl methanesulfonate. Geremy W. Knapp, Alan H. Tennant, and Russell D. Owen. Environmental Carcinogenesis Division, National Health and Environmental Effects Research Laboratory, U. S. Environmental Prote...

  13. Altered Clock and Lipid Metabolism-Related Genes in Atherosclerotic Mice Kept with Abnormal Lighting Condition

    PubMed Central

    Zhu, Zhu; Hua, Bingxuan; Shang, Zhanxian; Yuan, Gongsheng; Xu, Lirong; Li, Ermin; Li, Xiaobo; Yan, Zuoqin; Qian, Ruizhe

    2016-01-01

    Background. The risk of atherosclerosis is elevated in abnormal lipid metabolism and circadian rhythm disorder. We investigated whether abnormal lighting condition would have influenced the circadian expression of clock genes and clock-controlled lipid metabolism-related genes in ApoE-KO mice. Methods. A mouse model of atherosclerosis with circadian clock genes expression disorder was established using ApoE-KO mice (ApoE-KO LD/DL mice) by altering exposure to light. C57 BL/6J mice (C57 mice) and ApoE-KO mice (ApoE-KO mice) exposed to normal day and night and normal diet served as control mice. According to zeitgeber time samples were acquired, to test atheromatous plaque formation, serum lipids levels and rhythmicity, clock genes, and lipid metabolism-related genes along with Sirtuin 1 (Sirt1) levels and rhythmicity. Results. Atherosclerosis plaques were formed in the aortic arch of ApoE-KO LD/DL mice. The serum lipids levels and oscillations in ApoE-KO LD/DL mice were altered, along with the levels and diurnal oscillations of circadian genes, lipid metabolism-associated genes, and Sirt1 compared with the control mice. Conclusions. Abnormal exposure to light aggravated plaque formation and exacerbated disorders of serum lipids and clock genes, lipid metabolism genes and Sirt1 levels, and circadian oscillation. PMID:27631008

  14. Altered Clock and Lipid Metabolism-Related Genes in Atherosclerotic Mice Kept with Abnormal Lighting Condition

    PubMed Central

    Zhu, Zhu; Hua, Bingxuan; Shang, Zhanxian; Yuan, Gongsheng; Xu, Lirong; Li, Ermin; Li, Xiaobo; Yan, Zuoqin; Qian, Ruizhe

    2016-01-01

    Background. The risk of atherosclerosis is elevated in abnormal lipid metabolism and circadian rhythm disorder. We investigated whether abnormal lighting condition would have influenced the circadian expression of clock genes and clock-controlled lipid metabolism-related genes in ApoE-KO mice. Methods. A mouse model of atherosclerosis with circadian clock genes expression disorder was established using ApoE-KO mice (ApoE-KO LD/DL mice) by altering exposure to light. C57 BL/6J mice (C57 mice) and ApoE-KO mice (ApoE-KO mice) exposed to normal day and night and normal diet served as control mice. According to zeitgeber time samples were acquired, to test atheromatous plaque formation, serum lipids levels and rhythmicity, clock genes, and lipid metabolism-related genes along with Sirtuin 1 (Sirt1) levels and rhythmicity. Results. Atherosclerosis plaques were formed in the aortic arch of ApoE-KO LD/DL mice. The serum lipids levels and oscillations in ApoE-KO LD/DL mice were altered, along with the levels and diurnal oscillations of circadian genes, lipid metabolism-associated genes, and Sirt1 compared with the control mice. Conclusions. Abnormal exposure to light aggravated plaque formation and exacerbated disorders of serum lipids and clock genes, lipid metabolism genes and Sirt1 levels, and circadian oscillation.

  15. Altered Clock and Lipid Metabolism-Related Genes in Atherosclerotic Mice Kept with Abnormal Lighting Condition.

    PubMed

    Zhu, Zhu; Hua, Bingxuan; Shang, Zhanxian; Yuan, Gongsheng; Xu, Lirong; Li, Ermin; Li, Xiaobo; Sun, Ning; Yan, Zuoqin; Qian, Ruizhe; Lu, Chao

    2016-01-01

    Background. The risk of atherosclerosis is elevated in abnormal lipid metabolism and circadian rhythm disorder. We investigated whether abnormal lighting condition would have influenced the circadian expression of clock genes and clock-controlled lipid metabolism-related genes in ApoE-KO mice. Methods. A mouse model of atherosclerosis with circadian clock genes expression disorder was established using ApoE-KO mice (ApoE-KO LD/DL mice) by altering exposure to light. C57 BL/6J mice (C57 mice) and ApoE-KO mice (ApoE-KO mice) exposed to normal day and night and normal diet served as control mice. According to zeitgeber time samples were acquired, to test atheromatous plaque formation, serum lipids levels and rhythmicity, clock genes, and lipid metabolism-related genes along with Sirtuin 1 (Sirt1) levels and rhythmicity. Results. Atherosclerosis plaques were formed in the aortic arch of ApoE-KO LD/DL mice. The serum lipids levels and oscillations in ApoE-KO LD/DL mice were altered, along with the levels and diurnal oscillations of circadian genes, lipid metabolism-associated genes, and Sirt1 compared with the control mice. Conclusions. Abnormal exposure to light aggravated plaque formation and exacerbated disorders of serum lipids and clock genes, lipid metabolism genes and Sirt1 levels, and circadian oscillation.

  16. Altered Clock and Lipid Metabolism-Related Genes in Atherosclerotic Mice Kept with Abnormal Lighting Condition.

    PubMed

    Zhu, Zhu; Hua, Bingxuan; Shang, Zhanxian; Yuan, Gongsheng; Xu, Lirong; Li, Ermin; Li, Xiaobo; Sun, Ning; Yan, Zuoqin; Qian, Ruizhe; Lu, Chao

    2016-01-01

    Background. The risk of atherosclerosis is elevated in abnormal lipid metabolism and circadian rhythm disorder. We investigated whether abnormal lighting condition would have influenced the circadian expression of clock genes and clock-controlled lipid metabolism-related genes in ApoE-KO mice. Methods. A mouse model of atherosclerosis with circadian clock genes expression disorder was established using ApoE-KO mice (ApoE-KO LD/DL mice) by altering exposure to light. C57 BL/6J mice (C57 mice) and ApoE-KO mice (ApoE-KO mice) exposed to normal day and night and normal diet served as control mice. According to zeitgeber time samples were acquired, to test atheromatous plaque formation, serum lipids levels and rhythmicity, clock genes, and lipid metabolism-related genes along with Sirtuin 1 (Sirt1) levels and rhythmicity. Results. Atherosclerosis plaques were formed in the aortic arch of ApoE-KO LD/DL mice. The serum lipids levels and oscillations in ApoE-KO LD/DL mice were altered, along with the levels and diurnal oscillations of circadian genes, lipid metabolism-associated genes, and Sirt1 compared with the control mice. Conclusions. Abnormal exposure to light aggravated plaque formation and exacerbated disorders of serum lipids and clock genes, lipid metabolism genes and Sirt1 levels, and circadian oscillation. PMID:27631008

  17. Identification of mycoparasitism-related genes in Clonostachys rosea 67-1 active against Sclerotinia sclerotiorum

    PubMed Central

    Sun, Zhan-Bin; Sun, Man-Hong; Li, Shi-Dong

    2015-01-01

    Clonostachys rosea is a mycoparasite that has shown great potential in controlling various plant fungal pathogens. In order to find mycoparasitism-related genes in C. rosea, the transcriptome of the efficient isolate 67-1 in association with sclerotia of Sclerotinia sclerotiorum was sequenced and analysed. The results identified 26,351 unigenes with a mean length of 1,102 nucleotides, among which 18,525 were annotated in one or more databases of NR, KEGG, Swiss-Prot, GO and COG. Differentially expressed genes at 8 h, 24 h and 48 h after sclerotial induction were analysed, and 6,890 unigenes were upregulated compared with the control without sclerotia. 713, 1,008 and 1,929 genes were specifically upregulated expressed, while 1,646, 283 and 529 genes were specifically downregulated, respectively. Gene ontology terms analysis indicated that these genes were mainly involved in metabolism of biological process, catalysis of molecular function and cellular component. The expression levels of 12 genes that were upregulated after encountering with S. sclerotiorum were monitored using real-time PCR. The results indicated that the quantitative detection was consistent with the transcriptome analysis. The study provides transcriptional gene expression information on C. rosea parasitizing S. sclerotiorum and forms the basis for further investigation of mycoparasitism-related genes of C. rosea. PMID:26657839

  18. Identification of mycoparasitism-related genes in Clonostachys rosea 67-1 active against Sclerotinia sclerotiorum.

    PubMed

    Sun, Zhan-Bin; Sun, Man-Hong; Li, Shi-Dong

    2015-01-01

    Clonostachys rosea is a mycoparasite that has shown great potential in controlling various plant fungal pathogens. In order to find mycoparasitism-related genes in C. rosea, the transcriptome of the efficient isolate 67-1 in association with sclerotia of Sclerotinia sclerotiorum was sequenced and analysed. The results identified 26,351 unigenes with a mean length of 1,102 nucleotides, among which 18,525 were annotated in one or more databases of NR, KEGG, Swiss-Prot, GO and COG. Differentially expressed genes at 8 h, 24 h and 48 h after sclerotial induction were analysed, and 6,890 unigenes were upregulated compared with the control without sclerotia. 713, 1,008 and 1,929 genes were specifically upregulated expressed, while 1,646, 283 and 529 genes were specifically downregulated, respectively. Gene ontology terms analysis indicated that these genes were mainly involved in metabolism of biological process, catalysis of molecular function and cellular component. The expression levels of 12 genes that were upregulated after encountering with S. sclerotiorum were monitored using real-time PCR. The results indicated that the quantitative detection was consistent with the transcriptome analysis. The study provides transcriptional gene expression information on C. rosea parasitizing S. sclerotiorum and forms the basis for further investigation of mycoparasitism-related genes of C. rosea. PMID:26657839

  19. Rates and Routes of Electron Transfer of [NiFe]-Hydrogenase in an Enzymatic Fuel Cell.

    PubMed

    Petrenko, Alexander; Stein, Matthias

    2015-10-29

    Hydrogenase enzymes are being used in enzymatic fuel cells immobilized on a graphite or carbon electrode surface, for example. The enzyme is used for the anodic oxidation of molecular hydrogen (H2) to produce protons and electrons. The association and orientation of the enzyme at the anode electrode for a direct electron transfer is not completely resolved. The distal FeS-cluster in [NiFe]-hydrogenases contains a histidine residue which is known to play a critical role in the intermolecular electron transfer between the enzyme and the electrode surface. The [NiFe]-hydrogenase graphite electrode association was investigated using Brownian Dynamics simulations. Residues that were shown to be in proximity to the electrode surface were identified (His184, Ser196, Glu461, Glu464), and electron transfer routes connecting the distal FeS-cluster with the surface residues were investigated. Several possible pathways for electron transfer between the distal FeS-cluster and the terminal amino acid residues were probed in terms of their rates of electron transfer using DFT methods. The reorganization energies λ of the distal iron-sulfur cluster and coronene as a molecular model for graphite were calculated. The reorganization energy of the distal (His)(Cys)3 cluster was found to be not very different from that of a standard cubane clusters with a (Cys)4 coordination. Electronic coupling matrix elements and rates of electron transfer for the different pathways were calculated according to the Marcus equation. The rates for glutamate-mediated electrode binding were found to be incompatible with experimental data. A direct electron transfer from the histidine ligand of the distal FeS-cluster to the electrode yielded rates of electron transfer in excellent agreement with experiment. A second pathway, however, from the distal FeS-cluster to the Ser196 residue was found to be equally efficient and feasible. PMID:26218232

  20. Targeting intermediates of [FeFe]-hydrogenase by CO and CN vibrational signatures.

    PubMed

    Yu, Lian; Greco, Claudio; Bruschi, Maurizio; Ryde, Ulf; De Gioia, Luca; Reiher, Markus

    2011-05-01

    In this work, we employ density functional theory to assign vibrational signatures of [FeFe]-hydrogenase intermediates to molecular structures. For this purpose, we perform an exhaustive analysis of structures and harmonic vibrations of a series of CN and CO containing model clusters of the [FeFe]-hydrogenase enzyme active site considering also different charges, counterions, and solvents. The pure density functional BP86 in combination with a triple-ζ polarized basis set produce reliable molecular structures as well as harmonic vibrations. Calculated CN and CO stretching vibrations are analyzed separately. Scaled vibrational frequencies are then applied to assign intermediates in [FeFe]-hydrogenase's reaction cycle. The results nicely complement the previous studies of Darensbourg and Hall, and Zilberman et al. The infrared spectrum of the H(ox) form is in very good agreement with the calculated spectrum of the Fe(I)Fe(II) model complex featuring a free coordination site at the distal Fe atom, as well as, with the calculated spectra of the complexes in which H(2) or H(2)O are coordinated at this site. The spectrum of H(red) measured from Desulfovibrio desulfuricans is compatible with a mixture of a Fe(I)Fe(I) species with all terminal COs, and a Fe(I)Fe(I) species with protonated dtma ligand, while the spectrum of H(red) recently measured from Chlamydomonas reinhardtii is compatible with a mixture of a Fe(I)Fe(I) species with a bridged CO, and a Fe(II)Fe(II) species with a terminal hydride bound to the Fe atom.

  1. Metabolic control of Clostridium thermocellum via inhibition of hydrogenase activity and the glucose transport rate.

    PubMed

    Li, Hsin-Fen; Knutson, Barbara L; Nokes, Sue E; Lynn, Bert C; Flythe, Michael D

    2012-02-01

    Clostridium thermocellum has the ability to catabolize cellulosic biomass into ethanol, but acetic acid, lactic acid, carbon dioxide, and hydrogen gas (H(2)) are also produced. The effect of hydrogenase inhibitors (H(2), carbon monoxide (CO), and methyl viologen) on product selectivity was investigated. The anticipated effect of these hydrogenase inhibitors was to decrease acetate production. However, shifts to ethanol and lactate production are also observed as a function of cultivation conditions. When the sparge gas of cellobiose-limited chemostat cultures was switched from N(2) to H(2), acetate declined, and ethanol production increased 350%. In resting cell suspensions, lactate increased when H(2) or CO was the inhibitor or when the cells were held at elevated hyperbaric pressure (6.8 atm). In contrast, methyl-viologen-treated resting cells produced twice as much ethanol as the other treatments. The relationship of chemostat physiology to methyl viologen inhibition was revealed by glucose transport experiments, in which methyl viologen decreased the rate of glucose transport by 90%. C. thermocellum produces NAD(+) from NADH by H(2), lactate, and ethanol production. When the hydrogenases were inhibited, the latter two products increased. However, excess substrate availability causes fructose 1,6-diphosphate, the glycolytic intermediate that triggers lactate production, to increase. Compensatory ethanol production was observed when the chemostat fluid dilution rate or methyl viologen decreased substrate transport. This research highlights the complex effects of high concentrations of dissolved gases in fermentation, which are increasingly envisioned in microbial applications of H(2) production for the conversion of synthetic gases to chemicals. PMID:22218768

  2. The crystal structure of an oxygen-tolerant hydrogenase uncovers a novel iron-sulphur centre.

    PubMed

    Fritsch, Johannes; Scheerer, Patrick; Frielingsdorf, Stefan; Kroschinsky, Sebastian; Friedrich, Bärbel; Lenz, Oliver; Spahn, Christian M T

    2011-10-16

    Hydrogenases are abundant enzymes that catalyse the reversible interconversion of H(2) into protons and electrons at high rates. Those hydrogenases maintaining their activity in the presence of O(2) are considered to be central to H(2)-based technologies, such as enzymatic fuel cells and for light-driven H(2) production. Despite comprehensive genetic, biochemical, electrochemical and spectroscopic investigations, the molecular background allowing a structural interpretation of how the catalytic centre is protected from irreversible inactivation by O(2) has remained unclear. Here we present the crystal structure of an O(2)-tolerant [NiFe]-hydrogenase from the aerobic H(2) oxidizer Ralstonia eutropha H16 at 1.5 Å resolution. The heterodimeric enzyme consists of a large subunit harbouring the catalytic centre in the H(2)-reduced state and a small subunit containing an electron relay consisting of three different iron-sulphur clusters. The cluster proximal to the active site displays an unprecedented [4Fe-3S] structure and is coordinated by six cysteines. According to the current model, this cofactor operates as an electronic switch depending on the nature of the gas molecule approaching the active site. It serves as an electron acceptor in the course of H(2) oxidation and as an electron-delivering device upon O(2) attack at the active site. This dual function is supported by the capability of the novel iron-sulphur cluster to adopt three redox states at physiological redox potentials. The second structural feature is a network of extended water cavities that may act as a channel facilitating the removal of water produced at the [NiFe] active site. These discoveries will have an impact on the design of biological and chemical H(2)-converting catalysts that are capable of cycling H(2) in air.

  3. A Redox Active [2Fe-2S] Cluster on the Hydrogenase Maturase HydF.

    PubMed

    Shepard, Eric M; Byer, Amanda S; Betz, Jeremiah N; Peters, John W; Broderick, Joan B

    2016-06-28

    [FeFe]-hydrogenases are nature's most prolific hydrogen catalysts, excelling at facilely interconverting H2 and protons. The catalytic core common to all [FeFe]-hydrogenases is a complex metallocofactor, referred to as the H-cluster, which is composed of a standard [4Fe-4S] cluster linked through a bridging thiolate to a 2Fe subcluster harboring dithiomethylamine, carbon monoxide, and cyanide ligands. This 2Fe subcluster is synthesized and inserted into [FeFe]-hydrogenase by three maturase enzymes denoted HydE, HydF, and HydG. HydE and HydG are radical S-adenosylmethionine enzymes and synthesize the nonprotein ligands of the H-cluster. HydF is a GTPase that functions as a scaffold or carrier for 2Fe subcluster production. Herein, we utilize UV-visible, circular dichroism, and electron paramagnetic resonance spectroscopic studies to establish the existence of redox active [4Fe-4S] and [2Fe-2S] clusters bound to HydF. We have used spectroelectrochemical titrations to assign iron-sulfur cluster midpoint potentials, have shown that HydF purifies with a reduced [2Fe-2S] cluster in the absence of exogenous reducing agents, and have tracked iron-sulfur cluster spectroscopic changes with quaternary structural perturbations. Our results provide an important foundation for understanding the maturation process by defining the iron-sulfur cluster content of HydF prior to its interaction with HydE and HydG. We speculate that the [2Fe-2S] cluster of HydF either acts as a placeholder for HydG-derived Fe(CO)2CN species or serves as a scaffold for 2Fe subcluster assembly. PMID:27232385

  4. Differential Expression of Inflammation-Related Genes in Children with Down Syndrome

    PubMed Central

    Silva, Cláudia Regina Santos; Biselli-Périco, Joice Matos; Zampieri, Bruna Lancia; Silva, Wilson Araujo; de Souza, Jorge Estefano Santana; Bürger, Matheus Carvalho; Goloni-Bertollo, Eny Maria; Pavarino, Érika Cristina

    2016-01-01

    Objective. The aim of the study was to investigate the expression patterns of a specific set of genes involved in the inflammation process in children with Down Syndrome (DS) and children without the syndrome (control group) to identify differences that may be related to the immune abnormalities observed in DS individuals. Method. RNA samples were obtained from peripheral blood, and gene expression was quantified using the TaqMan® Array Plate Human Inflammation Kit, which facilitated the investigation into 92 inflammation-related genes and four reference genes using real-time polymerase chain reaction (qPCR). Results. Twenty genes showed differential expression in children with DS; 12 were overexpressed (PLA2G2D, CACNA1D, ALOX12, VCAM1, ICAM1, PLCD1, ADRB1, HTR3A, PDE4C, CASP1, PLA2G5, and PLCB4), and eight were underexpressed (LTA4H, BDKRB1, ADRB2, CD40LG, ITGAM, TNFRSF1B, ITGB1, and TBXAS1). After statistically correcting for the false discovery rate, only the genes BDKRB1 and LTA4H showed differential expression, and both were underexpressed within the DS group. Conclusion. DS children showed differential expression of inflammation-related genes that were not located on chromosome 21 compared with children without DS. The BDKRB1 and LTA4H genes may differentiate the case and control groups based on the inflammatory response, which plays an important role in DS pathogenesis. PMID:27293319

  5. Addiction and reward-related genes show altered expression in the postpartum nucleus accumbens

    PubMed Central

    Zhao, Changjiu; Eisinger, Brian Earl; Driessen, Terri M.; Gammie, Stephen C.

    2014-01-01

    Motherhood involves a switch in natural rewards, whereby offspring become highly rewarding. Nucleus accumbens (NAC) is a key CNS region for natural rewards and addictions, but to date no study has evaluated on a large scale the events in NAC that underlie the maternal change in natural rewards. In this study we utilized microarray and bioinformatics approaches to evaluate postpartum NAC gene expression changes in mice. Modular Single-set Enrichment Test (MSET) indicated that postpartum (relative to virgin) NAC gene expression profile was significantly enriched for genes related to addiction and reward in five of five independently curated databases (e.g., Malacards, Phenopedia). Over 100 addiction/reward related genes were identified and these included: Per1, Per2, Arc, Homer2, Creb1, Grm3, Fosb, Gabrb3, Adra2a, Ntrk2, Cry1, Penk, Cartpt, Adcy1, Npy1r, Htr1a, Drd1a, Gria1, and Pdyn. ToppCluster analysis found maternal NAC expression profile to be significantly enriched for genes related to the drug action of nicotine, ketamine, and dronabinol. Pathway analysis indicated postpartum NAC as enriched for RNA processing, CNS development/differentiation, and transcriptional regulation. Weighted Gene Coexpression Network Analysis (WGCNA) identified possible networks for transcription factors, including Nr1d1, Per2, Fosb, Egr1, and Nr4a1. The postpartum state involves increased risk for mental health disorders and MSET analysis indicated postpartum NAC to be enriched for genes related to depression, bipolar disorder (BPD), and schizophrenia. Mental health related genes included: Fabp7, Grm3, Penk, and Nr1d1. We confirmed via quantitative PCR Nr1d1, Per2, Grm3, Penk, Drd1a, and Pdyn. This study indicates for the first time that postpartum NAC involves large scale gene expression alterations linked to addiction and reward. Because the postpartum state also involves decreased response to drugs, the findings could provide insights into how to mitigate addictions. PMID:25414651

  6. Identification of novel thyroid cancer-related genes and chemicals using shortest path algorithm.

    PubMed

    Jiang, Yang; Zhang, Peiwei; Li, Li-Peng; He, Yi-Chun; Gao, Ru-jian; Gao, Yu-Fei

    2015-01-01

    Thyroid cancer is a typical endocrine malignancy. In the past three decades, the continued growth of its incidence has made it urgent to design effective treatments to treat this disease. To this end, it is necessary to uncover the mechanism underlying this disease. Identification of thyroid cancer-related genes and chemicals is helpful to understand the mechanism of thyroid cancer. In this study, we generalized some previous methods to discover both disease genes and chemicals. The method was based on shortest path algorithm and applied to discover novel thyroid cancer-related genes and chemicals. The analysis of the final obtained genes and chemicals suggests that some of them are crucial to the formation and development of thyroid cancer. It is indicated that the proposed method is effective for the discovery of novel disease genes and chemicals.

  7. Kinetics and thermodynamics of gas diffusion in a NiFe hydrogenase.

    PubMed

    Topin, Jérémie; Rousset, Marc; Antonczak, Serge; Golebiowski, Jérôme

    2012-03-01

    We have investigated O₂ and H₂ transport across a NiFe hydrogenase at the atomic scale by means of computational methods. The Wild Type protein has been compared with the V74Q mutant. Two distinct methodologies have been applied to study the gas access to the active site. Temperature locally enhanced sampling simulations have emphasized the importance of protein dynamics on gas diffusion. The O₂ diffusion free energy profiles, obtained by umbrella sampling, are in agreement with the known kinetic data and show that in the V74Q mutant, the inhibition process is lowered from both a kinetic and a thermodynamic point of view.

  8. Systematic Analysis of Integrated Gene Functional Network of Four Chronic Stress-related Lifestyle Disorders

    PubMed Central

    Roy, Souvick; Chakraborty, Abhik; Ghosh, Chinmoy; Banerjee, Birendranath

    2015-01-01

    Background: Stress is a term used to define factors involved in changes in the physiological balances resulting in disease conditions. Chronic exposure to stress conditions in modern lifestyles has resulted in a group of disorders called lifestyle disorders. Genetic background and environmental factors are interrelated to lifestyle in determining the health status of individuals. Hence, identification of disease-associated genes is the primary step toward explanations of pathogenesis of these diseases. In functional genomics, large-scale molecular and physiological data are used for the identification of causative genes associated with a disease. Aim: The objective of our study was to find a common set of genes involved in chronic stress-related lifestyle diseases such as cardiovascular diseases (CVDs), type 2 diabetes (T2D), hypertension (HTN), and obesity. Materials and Methods: In our study, we have performed a systematic analysis of the functional gene network of four chronic stress-related lifestyle diseases by retrieving genes from published databases. We have tried to systematically construct a functional protein-protein interaction (PPI) network. The goals of establishing this network were the functional enrichment study of interacting partners as well as functional disease ontology annotation (FunDO) of the enriched genes. Results: This study enabled the identification of key genes involved in these stress-related lifestyle diseases by prioritizing candidate genes based on their degree of involvement. In this systematic analysis, we have found key genes for these diseases based on their involvement and association at the gene network level and PPI. Conclusion: We have deciphered a group of genes that in combination play a crucial role and may impact the function of the whole genome in the four lifestyle disorders mentioned. PMID:27330735

  9. Altered Expression of Diabetes-Related Genes in Alzheimer's Disease Brains: The Hisayama Study

    PubMed Central

    Hokama, Masaaki; Oka, Sugako; Leon, Julio; Ninomiya, Toshiharu; Honda, Hiroyuki; Sasaki, Kensuke; Iwaki, Toru; Ohara, Tomoyuki; Sasaki, Tomio; LaFerla, Frank M.; Kiyohara, Yutaka; Nakabeppu, Yusaku

    2014-01-01

    Diabetes mellitus (DM) is considered to be a risk factor for dementia including Alzheimer's disease (AD). However, the molecular mechanism underlying this risk is not well understood. We examined gene expression profiles in postmortem human brains donated for the Hisayama study. Three-way analysis of variance of microarray data from frontal cortex, temporal cortex, and hippocampus was performed with the presence/absence of AD and vascular dementia, and sex, as factors. Comparative analyses of expression changes in the brains of AD patients and a mouse model of AD were also performed. Relevant changes in gene expression identified by microarray analysis were validated by quantitative real-time reverse-transcription polymerase chain reaction and western blotting. The hippocampi of AD brains showed the most significant alteration in gene expression profile. Genes involved in noninsulin-dependent DM and obesity were significantly altered in both AD brains and the AD mouse model, as were genes related to psychiatric disorders and AD. The alterations in the expression profiles of DM-related genes in AD brains were independent of peripheral DM-related abnormalities. These results indicate that altered expression of genes related to DM in AD brains is a result of AD pathology, which may thereby be exacerbated by peripheral insulin resistance or DM. PMID:23595620

  10. Identifying and prioritizing disease-related genes based on the network topological features.

    PubMed

    Li, Zhan-Chao; Lai, Yan-Hua; Chen, Li-Li; Xie, Yun; Dai, Zong; Zou, Xiao-Yong

    2014-12-01

    Identifying and prioritizing disease-related genes are the most important steps for understanding the pathogenesis and discovering the therapeutic targets. The experimental examination of these genes is very expensive and laborious, and usually has a higher false positive rate. Therefore, it is highly desirable to develop computational methods for the identification and prioritization of disease-related genes. In this study, we develop a powerful method to identify and prioritize candidate disease genes. The novel network topological features with local and global information are proposed and adopted to characterize genes. The performance of these novel features is verified based on the 10-fold cross-validation test and leave-one-out cross-validation test. The proposed features are compared with the published features, and fused strategy is investigated by combining the current features with the published features. And, these combination features are also utilized to identify and prioritize Parkinson's disease-related genes. The results indicate that identified genes are highly related to some molecular process and biological function, which provides new clues for researching pathogenesis of Parkinson's disease. The source code of Matlab is freely available on request from the authors. PMID:25183318

  11. Mapping and annotating obesity-related genes in pig and human genomes.

    PubMed

    Martelli, Pier Luigi; Fontanesi, Luca; Piovesan, Damiano; Fariselli, Piero; Casadio, Rita

    2014-01-01

    Background. Obesity is a major health problem in both developed and emerging countries. Obesity is a complex disease whose etiology involves genetic factors in strong interplay with environmental determinants and lifestyle. The discovery of genetic factors and biological pathways underlying human obesity is hampered by the difficulty in controlling the genetic background of human cohorts. Animal models are then necessary to further dissect the genetics of obesity. Pig has emerged as one of the most attractive models, because of the similarity with humans in the mechanisms regulating the fat deposition. Results. We collected the genes related to obesity in humans and to fat deposition traits in pig. We localized them on both human and pig genomes, building a map useful to interpret comparative studies on obesity. We characterized the collected genes structurally and functionally with BAR+ and mapped them on KEGG pathways and on STRING protein interaction network. Conclusions. The collected set consists of 361 obesity related genes in human and pig genomes. All genes were mapped on the human genome, and 54 could not be localized on the pig genome (release 2012). Only for 3 human genes there is no counterpart in pig, confirming that this animal is a good model for human obesity studies. Obesity related genes are mostly involved in regulation and signaling processes/pathways and relevant connection emerges between obesity-related genes and diseases such as cancer and infectious diseases.

  12. Search of phenotype related candidate genes using gene ontology-based semantic similarity and protein interaction information: application to Brugada syndrome.

    PubMed

    Massanet, Raimon; Gallardo-Chacon, Joan-Josep; Caminal, Pere; Perera, Alexandre

    2009-01-01

    This work presents a methodology for finding phenotype candidate genes starting from a set of known related genes. This is accomplished by automatically mining and organizing the available scientific literature using Gene Ontology-based semantic similarity. As a case study, Brugada syndrome related genes have been used as input in order to obtain a list of other possible candidate genes related with this disease. Brugada anomaly produces a typical alteration in the Electrocardiogram and carriers of the disease show an increased probability of sudden death. Results show a set of semantically coherent proteins that are shown to be related with synaptic transmission and muscle contraction physiological processes.

  13. Starvation resistance and tissue-specific gene expression of stress-related genes in a naturally inbred ant population

    PubMed Central

    Bos, Nick; Pulliainen, Unni; Sundström, Liselotte; Freitak, Dalial

    2016-01-01

    Starvation is one of the most common and severe stressors in nature. Not only does it lead to death if not alleviated, it also forces the starved individual to allocate resources only to the most essential processes. This creates energetic trade-offs which can lead to many secondary challenges for the individual. These energetic trade-offs could be exacerbated in inbred individuals, which have been suggested to have a less efficient metabolism. Here, we studied the effect of inbreeding on starvation resistance in a natural population of Formica exsecta ants, with a focus on survival and tissue-specific expression of stress, metabolism and immunity-related genes. Starvation led to large tissue-specific changes in gene expression, but inbreeding had little effect on most of the genes studied. Our results illustrate the importance of studying stress responses in different tissues instead of entire organisms. PMID:27152219

  14. Starvation resistance and tissue-specific gene expression of stress-related genes in a naturally inbred ant population.

    PubMed

    Bos, Nick; Pulliainen, Unni; Sundström, Liselotte; Freitak, Dalial

    2016-04-01

    Starvation is one of the most common and severe stressors in nature. Not only does it lead to death if not alleviated, it also forces the starved individual to allocate resources only to the most essential processes. This creates energetic trade-offs which can lead to many secondary challenges for the individual. These energetic trade-offs could be exacerbated in inbred individuals, which have been suggested to have a less efficient metabolism. Here, we studied the effect of inbreeding on starvation resistance in a natural population of Formica exsecta ants, with a focus on survival and tissue-specific expression of stress, metabolism and immunity-related genes. Starvation led to large tissue-specific changes in gene expression, but inbreeding had little effect on most of the genes studied. Our results illustrate the importance of studying stress responses in different tissues instead of entire organisms. PMID:27152219

  15. Differential gene expression in mouse retina related to regional differences in vulnerability to hyperoxia

    PubMed Central

    Natoli, Riccardo; Valter, Krisztina; Stone, Jonathan

    2010-01-01

    Purpose In the C57BL/6J mouse retina, hyperoxia-induced degeneration of photoreceptors shows strong regional variation, beginning at a locus ~0.5 mm inferior to the optic disc. To identify gene expression differences that might underlie this variability in vulnerability, we have used microarray techniques to describe regional (superior-inferior) variations in gene expression in the retina. Methods Young adult C57BL/6J mice raised in dim cyclic illumination (12 h at 5 lx and 12 h in darkness) were exposed to hyperoxia (75% oxygen for two weeks). Retinas were collected from hyperoxia-exposed and control animals without fixation and divided into superior and inferior halves. RNA was extracted from each sample, purified, and hybridized to Mouse Gene 1.0 ST arrays (Affymetrix). The consistency of the microarray results was assessed using quantitative PCR for selected genes. Expression data were analyzed to identify genes and ncRNAs whose differential expression between the superior and inferior retina could be associated with relative vulnerability to hyperoxia. Results In control retinas, only two genes showed a fold difference in expression >2 between the superior and inferior retina; another 25 showed a fold difference of 1.5–2.0. Of these 27, the functions of six genes, including ventral anterior homeobox containing gene 2 (Vax2) and T-box 5 (Tbox5), are related to parameters of anatomic development and the functions of five are related to sensory perception. Among the latter, short-wave-sensitive cone opsin (Opn1sw) was more strongly expressed in the inferior retina and medium-wave-sensitive cone opsin (Opn1mw) in the superior retina. This is consistent with known differences in S- and M-cone distribution, confirming our separation of retinal regions. The highest fold difference was reported for membrane metalloendopeptidase (Mme), a member from the metallothionein group of cytoprotective proteins. To identify genes whose regulation by hyperoxia was

  16. EST sequencing and gene expression profiling of defence-related genes from Persea americana infected with Phytophthora cinnamomi

    PubMed Central

    2011-01-01

    Background Avocado (Persea americana) belongs to the Lauraceae family and is an important commercial fruit crop in over 50 countries. The most serious pathogen affecting avocado production is Phytophthora cinnamomi which causes Phytophthora root rot (PRR). Root pathogens such as P. cinnamomi and their interactions with hosts are poorly understood and despite the importance of both the avocado crop and the effect Phytophthora has on its cultivation, there is a lack of molecular knowledge underpinning our understanding of defence strategies against the pathogen. In order to initiate a better understanding of host-specific defence we have generated EST data using 454 pyrosequencing and profiled nine defence-related genes from Pc-infected avocado roots. Results 2.0 Mb of data was generated consisting of ~10,000 reads on a single lane of the GS FLX platform. Using the Newbler assembler 371 contigs were assembled, of which 367 are novel for Persea americana. Genes were classified according to Gene Ontology terms. In addition to identifying root-specific ESTs we were also able to identify and quantify the expression of nine defence-related genes that were differentially regulated in response to P. cinnamomi. Genes such as metallothionein, thaumatin and the pathogenesis related PsemI, mlo and profilin were found to be differentially regulated. Conclusions This is the first study in elucidating the avocado root transcriptome as well as identifying defence responses of avocado roots to the root pathogen P. cinnamomi. Our data is currently the only EST data that has been generated for avocado rootstocks, and the ESTs identified in this study have already been useful in identifying defence-related genes as well as providing gene information for other studies looking at processes such as ROS regulation as well as hypoxia in avocado roots. Our EST data will aid in the elucidation of the avocado transcriptome and identification of markers for improved rootstock breeding and

  17. Recognition- and defense-related gene expression at 3 resynthesis stages in lichen symbionts.

    PubMed

    Athukorala, Sarangi N P; Piercey-Normore, Michele D

    2015-01-01

    Recognition and defense responses are early events in plant-pathogen interactions and between lichen symbionts. The effect of elicitors on responses between lichen symbionts is not well understood. The objective of this study was to compare the difference in recognition- and defense-related gene expression as a result of culture extracts (containing secreted water-soluble elicitors) from compatible and incompatible interactions at each of 3 resynthesis stages in the symbionts of Cladonia rangiferina. This study investigated gene expression by quantitative PCR in cultures of C. rangiferina and its algal partner, Asterochloris glomerata/irregularis, after incubation with liquid extracts from cultures of compatible and incompatible interactions at 3 early resynthesis stages. Recognition-related genes were significantly upregulated only after physical contact, demonstrating symbiont recognition in later resynthesis stages than expected. One of 3 defense-related genes, chit, showed significant downregulation in early resynthesis stages and upregulation in the third resynthesis stage, demonstrating a need for the absence of chitinase early in thallus formation and a need for its presence in later stages as an algal defense reaction. This study revealed that recognition- and defense-related genes are triggered by components in culture extracts at 3 stages of resynthesis, and some defense-related genes may be induced throughout thallus growth. The parasitic nature of the interaction shows parallels between lichen symbionts and plant pathogenic systems. PMID:25485526

  18. Recognition- and defense-related gene expression at 3 resynthesis stages in lichen symbionts.

    PubMed

    Athukorala, Sarangi N P; Piercey-Normore, Michele D

    2015-01-01

    Recognition and defense responses are early events in plant-pathogen interactions and between lichen symbionts. The effect of elicitors on responses between lichen symbionts is not well understood. The objective of this study was to compare the difference in recognition- and defense-related gene expression as a result of culture extracts (containing secreted water-soluble elicitors) from compatible and incompatible interactions at each of 3 resynthesis stages in the symbionts of Cladonia rangiferina. This study investigated gene expression by quantitative PCR in cultures of C. rangiferina and its algal partner, Asterochloris glomerata/irregularis, after incubation with liquid extracts from cultures of compatible and incompatible interactions at 3 early resynthesis stages. Recognition-related genes were significantly upregulated only after physical contact, demonstrating symbiont recognition in later resynthesis stages than expected. One of 3 defense-related genes, chit, showed significant downregulation in early resynthesis stages and upregulation in the third resynthesis stage, demonstrating a need for the absence of chitinase early in thallus formation and a need for its presence in later stages as an algal defense reaction. This study revealed that recognition- and defense-related genes are triggered by components in culture extracts at 3 stages of resynthesis, and some defense-related genes may be induced throughout thallus growth. The parasitic nature of the interaction shows parallels between lichen symbionts and plant pathogenic systems.

  19. Glutamate-related gene expression changes with age in the mouse auditory midbrain.

    PubMed

    Tadros, Sherif F; D'Souza, Mary; Zettel, Martha L; Zhu, Xiaoxia; Waxmonsky, Nicole C; Frisina, Robert D

    2007-01-01

    Glutamate is the main excitatory neurotransmitter in both the peripheral and central auditory systems. Changes of glutamate and glutamate-related genes with age may be an important factor in the pathogenesis of age-related hearing loss-presbycusis. In this study, changes in glutamate-related mRNA gene expression in the CBA mouse inferior colliculus with age and hearing loss were examined and correlations were sought between these changes and functional hearing measures, such as the auditory brainstem response (ABR) and distortion product otoacoustic emissions (DPOAEs). Gene expression of 68 glutamate-related genes was investigated using both genechip microarray and real-time PCR (qPCR) molecular techniques for four different age/hearing loss CBA mouse subject groups. Two genes showed consistent differences between groups for both the genechip and qPCR. Pyrroline-5-carboxylate synthetase enzyme (Pycs) showed down-regulation with age and a high-affinity glutamate transporter (Slc1a3) showed up-regulation with age and hearing loss. Since Pycs plays a role in converting glutamate to proline, its deficiency in old age may lead to both glutamate increases and proline deficiencies in the auditory midbrain, playing a role in the subsequent inducement of glutamate toxicity and loss of proline neuroprotective effects. The up-regulation of Slc1a3 gene expression may reflect a cellular compensatory mechanism to protect against age-related glutamate or calcium excitoxicity.

  20. Identification of genes related to Paulownia witches' broom by AFLP and MSAP.

    PubMed

    Cao, Xibing; Fan, Guoqiang; Deng, Minjie; Zhao, Zhenli; Dong, Yanpeng

    2014-08-21

    DNA methylation is believed to play important roles in regulating gene expression in plant growth and development. Paulownia witches' broom (PaWB) infection has been reported to be related to gene expression changes in paulownia plantlets. To determine whether DNA methylation is associated with gene expression changes in response to phytoplasma, we investigated variations in genomic DNA sequence and methylation in PaWB plantlets treated with methyl methane sulfonate (MMS) using amplified fragment length polymorphism (AFLP) and methylation-sensitive amplification polymorphism (MSAP) techniques, respectively. The results indicated that PaWB seedings recovered a normal morphology after treatment with more than 15 mg·L(-1) MMS. PaWB infection did not cause changes of the paulownia DNA sequence at the AFLP level; However, DNA methylation levels and patterns were altered. Quantitative real-time PCR (qRT-PCR) showed that three of the methylated genes were up-regulated and three were down-regulated in the MMS-treated PaWB plantlets that had regained healthy morphology. These six genes might be involved in transcriptional regulation, plant defense, signal transduction and energy. The possible roles of these genes in PaWB are discussed. The results showed that changes of DNA methylation altered gene expression levels, and that MSAP might help identify genes related to PaWB.

  1. Identification of genes related to Paulownia witches' broom by AFLP and MSAP.

    PubMed

    Cao, Xibing; Fan, Guoqiang; Deng, Minjie; Zhao, Zhenli; Dong, Yanpeng

    2014-01-01

    DNA methylation is believed to play important roles in regulating gene expression in plant growth and development. Paulownia witches' broom (PaWB) infection has been reported to be related to gene expression changes in paulownia plantlets. To determine whether DNA methylation is associated with gene expression changes in response to phytoplasma, we investigated variations in genomic DNA sequence and methylation in PaWB plantlets treated with methyl methane sulfonate (MMS) using amplified fragment length polymorphism (AFLP) and methylation-sensitive amplification polymorphism (MSAP) techniques, respectively. The results indicated that PaWB seedings recovered a normal morphology after treatment with more than 15 mg·L(-1) MMS. PaWB infection did not cause changes of the paulownia DNA sequence at the AFLP level; However, DNA methylation levels and patterns were altered. Quantitative real-time PCR (qRT-PCR) showed that three of the methylated genes were up-regulated and three were down-regulated in the MMS-treated PaWB plantlets that had regained healthy morphology. These six genes might be involved in transcriptional regulation, plant defense, signal transduction and energy. The possible roles of these genes in PaWB are discussed. The results showed that changes of DNA methylation altered gene expression levels, and that MSAP might help identify genes related to PaWB. PMID:25196603

  2. Identification of Genes Related to Paulownia Witches’ Broom by AFLP and MSAP

    PubMed Central

    Cao, Xibing; Fan, Guoqiang; Deng, Minjie; Zhao, Zhenli; Dong, Yanpeng

    2014-01-01

    DNA methylation is believed to play important roles in regulating gene expression in plant growth and development. Paulownia witches’ broom (PaWB) infection has been reported to be related to gene expression changes in paulownia plantlets. To determine whether DNA methylation is associated with gene expression changes in response to phytoplasma, we investigated variations in genomic DNA sequence and methylation in PaWB plantlets treated with methyl methane sulfonate (MMS) using amplified fragment length polymorphism (AFLP) and methylation-sensitive amplification polymorphism (MSAP) techniques, respectively. The results indicated that PaWB seedings recovered a normal morphology after treatment with more than 15 mg·L−1 MMS. PaWB infection did not cause changes of the paulownia DNA sequence at the AFLP level; However, DNA methylation levels and patterns were altered. Quantitative real-time PCR (qRT-PCR) showed that three of the methylated genes were up-regulated and three were down-regulated in the MMS-treated PaWB plantlets that had regained healthy morphology. These six genes might be involved in transcriptional regulation, plant defense, signal transduction and energy. The possible roles of these genes in PaWB are discussed. The results showed that changes of DNA methylation altered gene expression levels, and that MSAP might help identify genes related to PaWB. PMID:25196603

  3. NHR-23 dependent collagen and hedgehog-related genes required for molting

    SciTech Connect

    Kouns, Nathaniel A.; Nakielna, Johana; Behensky, Frantisek; Krause, Michael W.; Kostrouch, Zdenek; Kostrouchova, Marta

    2011-10-07

    Highlights: {yields} NHR-23 is a critical regulator of nematode development and molting. {yields} The manuscript characterizes the loss-of-function phenotype of an nhr-23 mutant. {yields} Whole genome expression analysis identifies new potential targets of NHR-23. {yields} Hedgehog-related genes are identified as NHR-23 dependent genes. {yields} New link between sterol mediated signaling and regulation by NHR-23 is found. -- Abstract: NHR-23, a conserved member of the nuclear receptor family of transcription factors, is required for normal development in Caenorhabditis elegans where it plays a critical role in growth and molting. In a search for NHR-23 dependent genes, we performed whole genome comparative expression microarrays on both control and nhr-23 inhibited synchronized larvae. Genes that decreased in response to nhr-23 RNAi included several collagen genes. Unexpectedly, several hedgehog-related genes were also down-regulated after nhr-23 RNAi. A homozygous nhr-23 deletion allele was used to confirm the RNAi knockdown phenotypes and the changes in gene expression. Our results indicate that NHR-23 is a critical co-regulator of functionally linked genes involved in growth and molting and reveal evolutionary parallels among the ecdysozoa.

  4. Isolation and characterization of ripening related pectin methylesterase inhibitor gene from banana fruit.

    PubMed

    Srivastava, Sudhakar; Gupta, Sanjay Mohan; Sane, Aniruddha P; Nath, Pravendra

    2012-04-01

    Identification of ethylene-regulated and ripening-related genes from banana (Musa acuminata Var. Harichaal) fruits using DDRT-PCR led to the isolation of differentially expressed partial cDNA of pectin methylesterase inhibitor (MaPMEI) gene. Its full-length cDNA sequence consisted of a 567 bp ORF, encoding a protein of 189 aa with deduced molecular mass 19.6 kDa. Expression pattern of MaPMEI gene revealed that upon ethylene treatment, this gene is up-regulated initially giving maximum expression in post-climacteric stage then decreases slightly in later stages of ripening. 1-MCP, a known ethylene perception inhibitor, inhibits both fruit ripening as well as the transcript level of this gene. Also, the transcripts of MaPMEI gene were not detected during the short time ethylene treatment suggesting this gene appears to be not directly induced by ethylene. Interestingly, MaPMEI gene showed fruit specific expression that indicates its possible role in the regulations of PMEs in fruits. In silico analysis revealed a predicted signal peptide sequence necessary for localization of MaPMEI in the cell wall. Furthermore, the four Cys residues involved in disulfide bridges are conserved in MaPMEI similar to other PMEIs and invertase inhibitors. Phylogenetic analysis further suggests that the MaPMEI identified in this study is more closely related to PMEIs than to invertase inhibitors. PMID:23573057

  5. Family business: the multidrug-resistance related protein (MRP) ABC transporter genes in Arabidopsis thaliana.

    PubMed

    Kolukisaoglu, H Uner; Bovet, Lucien; Klein, Markus; Eggmann, Thomas; Geisler, Markus; Wanke, Dierk; Martinoia, Enrico; Schulz, Burkhard

    2002-11-01

    Despite the completion of the sequencing of the entire genome of Arabidopsis thaliana (L.) Heynh., the exact determination of each single gene and its function remains an open question. This is especially true for multigene families. An approach that combines analysis of genomic structure, expression data and functional genomics to ascertain the role of the members of the multidrug-resistance-related protein ( MRP) gene family, a subfamily of the ATP-binding cassette (ABC) transporters from Arabidopsis is presented. We used cDNA sequencing and alignment-based re-annotation of genomic sequences to define the exact genic structure of all known AtMRP genes. Analysis of promoter regions suggested different induction conditions even for closely related genes. Expression analysis for the entire gene family confirmed these assumptions. Phylogenetic analysis and determination of segmental duplication in the regions of AtMRP genes revealed that the evolution of the extraordinarily high number of ABC transporter genes in plants cannot solely be explained by polyploidisation during the evolution of the Arabidopsis genome. Interestingly MRP genes from Oryza sativa L. (rice; OsMRP) show very similar genomic structures to those from Arabidopsis. Screening of large populations of T-DNA-mutagenised lines of A. thaliana resulted in the isolation of AtMRP insertion mutants. This work opens the way for the defined analysis of a multigene family of important membrane transporters whose broad variety of functions expands their traditional role as cellular detoxifiers. PMID:12430019

  6. Massive Expansion of Ubiquitination-Related Gene Families within the Chlamydiae

    PubMed Central

    Domman, Daryl; Collingro, Astrid; Lagkouvardos, Ilias; Gehre, Lena; Weinmaier, Thomas; Rattei, Thomas; Subtil, Agathe; Horn, Matthias

    2014-01-01

    Gene loss, gain, and transfer play an important role in shaping the genomes of all organisms; however, the interplay of these processes in isolated populations, such as in obligate intracellular bacteria, is less understood. Despite a general trend towards genome reduction in these microbes, our phylogenomic analysis of the phylum Chlamydiae revealed that within the family Parachlamydiaceae, gene family expansions have had pronounced effects on gene content. We discovered that the largest gene families within the phylum are the result of rapid gene birth-and-death evolution. These large gene families are comprised of members harboring eukaryotic-like ubiquitination-related domains, such as F-box and BTB-box domains, marking the largest reservoir of these proteins found among bacteria. A heterologous type III secretion system assay suggests that these proteins function as effectors manipulating the host cell. The large disparity in copy number of members in these families between closely related organisms suggests that nonadaptive processes might contribute to the evolution of these gene families. Gene birth-and-death evolution in concert with genomic drift might represent a previously undescribed mechanism by which isolated bacterial populations diversify. PMID:25069652

  7. Suppression of PCD-related genes affects salt tolerance in Arabidopsis.

    PubMed

    Bahieldin, Ahmed; Alqarni, Dhafer A M; Atef, Ahmed; Gadalla, Nour O; Al-matary, Mohammed; Edris, Sherif; Al-Kordy, Magdy A; Makki, Rania M; Al-Doss, Abdullah A; Sabir, Jamal S M; Mutwakil, Mohammed H Z; El-Domyati, Fotouh M

    2016-01-01

    This work aims at examining a natural exciting phenomenon suggesting that suppression of genes inducing programmed cell death (PCD) might confer tolerance against abiotic stresses in plants. PCD-related genes were induced in tobacco under oxalic acid (OA) treatment (20 mM), and plant cells were characterized to confirm the incidence of PCD. The results indicated that PCD was triggered 24 h after the exposure to OA. Then, RNAs were extracted from tobacco cells 0, 2, 6, 12 and 24 h after treatment for deep sequencing. RNA-Seq analyses were done with a special emphasis to clusters whose PCD-related genes were upregulated after 2 h of OA exposure. Accordingly, 23 tobacco PCD-related genes were knocked down via virus-induced gene silencing (VIGS), whereas our results indicated the influence of five of them on inducing or suppressing PCD. Knockout T-DNA insertion mutants of these five genes in Arabidopsis were tested under salt stress (0, 100, 150, and 200 mM NaCl), and the results indicated that a mutant of an antiapoptotic gene, namely Bax Inhibitor-1 (BI-1), whose VIGS induced PCD in tobacco, was salt sensitive, while a mutant of an apoptotic gene, namely mildew resistance locus O (Mlo), whose VIGS suppressed PCD, was salt tolerant as compared to the WT (Col) control. These data support our hypothesis that retarding PCD-inducing genes can result in higher levels of salt tolerance, while retarding PCD-suppressing genes can result in lower levels of salt tolerance in plants.

  8. Suppression of PCD-related genes affects salt tolerance in Arabidopsis.

    PubMed

    Bahieldin, Ahmed; Alqarni, Dhafer A M; Atef, Ahmed; Gadalla, Nour O; Al-matary, Mohammed; Edris, Sherif; Al-Kordy, Magdy A; Makki, Rania M; Al-Doss, Abdullah A; Sabir, Jamal S M; Mutwakil, Mohammed H Z; El-Domyati, Fotouh M

    2016-01-01

    This work aims at examining a natural exciting phenomenon suggesting that suppression of genes inducing programmed cell death (PCD) might confer tolerance against abiotic stresses in plants. PCD-related genes were induced in tobacco under oxalic acid (OA) treatment (20 mM), and plant cells were characterized to confirm the incidence of PCD. The results indicated that PCD was triggered 24 h after the exposure to OA. Then, RNAs were extracted from tobacco cells 0, 2, 6, 12 and 24 h after treatment for deep sequencing. RNA-Seq analyses were done with a special emphasis to clusters whose PCD-related genes were upregulated after 2 h of OA exposure. Accordingly, 23 tobacco PCD-related genes were knocked down via virus-induced gene silencing (VIGS), whereas our results indicated the influence of five of them on inducing or suppressing PCD. Knockout T-DNA insertion mutants of these five genes in Arabidopsis were tested under salt stress (0, 100, 150, and 200 mM NaCl), and the results indicated that a mutant of an antiapoptotic gene, namely Bax Inhibitor-1 (BI-1), whose VIGS induced PCD in tobacco, was salt sensitive, while a mutant of an apoptotic gene, namely mildew resistance locus O (Mlo), whose VIGS suppressed PCD, was salt tolerant as compared to the WT (Col) control. These data support our hypothesis that retarding PCD-inducing genes can result in higher levels of salt tolerance, while retarding PCD-suppressing genes can result in lower levels of salt tolerance in plants. PMID:27052474

  9. Tamoxifen Induces Expression of Immune Response-Related Genes in Cultured Normal Human Mammary Epithelial Cells

    PubMed Central

    Schild-Hay, Laura J.; Leil, Tarek A.; Divi, Rao L.; Olivero, Ofelia, A.; Weston, Ainsley; Poirier, Miriam C.

    2008-01-01

    Use of tamoxifen (TAM) is associated with a 50% reduction in breast cancer incidence and an increase in endometrial cancer incidence. Here, we documented TAM-induced gene expression changes in cultured normal human mammary epithelial cells (NHMEC strains numbered 5, 16 and 40), established from tissue taken at reduction mammoplasty from 3 individuals. Cells exposed to 0, 10 or 50 μM TAM for 48 hours were evaluated for (E)-α-(deoxyguanosin-N2-yl)-tamoxifen (dG-N2-TAM) adduct formation by TAM-DNA (DNA modified with dG-N2-TAM) chemiluminescence immunoassay (CIA), gene expression changes using NCI DNA-oligonucleotide microarray, and real time (RT)-PCR. At 48 hr, cells exposed to 10 μM and 50 μM TAM were 85.6% and 48.4% viable, respectively, and there were no measurable dG-N2-TAM adducts. For microarray, cells were exposed to 10 μM TAM and genes with expression changes of ≥ 3-fold were as follows: thirteen genes up-regulated and one down-related for strain 16; seventeen genes up-regulated for strain 5; and eleven genes up-regulated for strain 40. Interferon-inducible genes (IFITM1, IFIT1, IFNA1, MXI and GIP3), and a potassium ion channel (KCNJ1) were up-regulated in all 3 strains. No significant expression changes were found for genes related to estrogen or xenobiotic metabolism. RT-PCR revealed up-regulation of interferon α (IFNA1) and confirmed the TAM-induced up-regulation of the genes identified by microarray, with the exception of GIP3 and MX1, which were not up-regulated in strain 40. Induction of interferon-related genes in the three NHMEC strains suggests that, in addition to hormonal effects, TAM exposure may enhance immune response in normal breast tissue. PMID:19155303

  10. Transcriptional profiling shows altered expression of wnt pathway- and lipid metabolism-related genes as well as melanogenesis-related genes in melasma.

    PubMed

    Kang, Hee Young; Suzuki, Itaru; Lee, Dong Jun; Ha, Jaehyun; Reiniche, Pascale; Aubert, Jérôme; Deret, Sophie; Zugaj, Didier; Voegel, Johannes J; Ortonne, Jean-Paul

    2011-08-01

    Melasma is a commonly acquired hyperpigmentary disorder of the face, but its pathogenesis is poorly understood and its treatment remains challenging. We conducted a comparative histological study on lesional and perilesional normal skin to clarify the histological nature of melasma. Significantly, higher amounts of melanin and of melanogenesis-associated proteins were observed in the epidermis of lesional skin, and the mRNA level of tyrosinase-related protein 1 was higher in lesional skin, indicating regulation at the mRNA level. However, melanocyte numbers were comparable between lesional and perilesional skin. A transcriptomic study was undertaken to identify genes involved in the pathology of melasma. A total of 279 genes were found to be differentially expressed in lesional and perilesional skin. As was expected, the mRNA levels of a number of known melanogenesis-associated genes, such as tyrosinase, were found to be elevated in lesional skin. Bioinformatics analysis revealed that the most lipid metabolism-associated genes were downregulated in lesional skin, and this finding was supported by an impaired barrier function in melasma. Interestingly, a subset of Wnt signaling modulators, including Wnt inhibitory factor 1, secreted frizzled-related protein 2, and Wnt5a, were also found to be upregulated in lesional skin. Immunohistochemistry confirmed the higher expression of these factors in melasma lesions.

  11. Molecular evolution of candidate genes for crop-related traits in sunflower (Helianthus annuus L.).

    PubMed

    Mandel, Jennifer R; McAssey, Edward V; Nambeesan, Savithri; Garcia-Navarro, Elena; Burke, John M

    2014-01-01

    Evolutionary analyses aimed at detecting the molecular signature of selection during crop domestication and/or improvement can be used to identify genes or genomic regions of likely agronomic importance. Here, we describe the DNA sequence-based characterization of a pool of candidate genes for crop-related traits in sunflower. These genes, which were identified based on homology to genes of known effect in other study systems, were initially sequenced from a panel of improved lines. All genes that exhibited a paucity of sequence diversity, consistent with the possible effects of selection during the evolution of cultivated sunflower, were then sequenced from a panel of wild sunflower accessions an outgroup. These data enabled formal tests for the effects of selection in shaping sequence diversity at these loci. When selection was detected, we further sequenced these genes from a panel of primitive landraces, thereby allowing us to investigate the likely timing of selection (i.e., domestication vs. improvement). We ultimately identified seven genes that exhibited the signature of positive selection during either domestication or improvement. Genetic mapping of a subset of these genes revealed co-localization between candidates for genes involved in the determination of flowering time, seed germination, plant growth/development, and branching and QTL that were previously identified for these traits in cultivated × wild sunflower mapping populations. PMID:24914686

  12. X-linked intellectual disability related genes disrupted by balanced X-autosome translocations.

    PubMed

    Moysés-Oliveira, Mariana; Guilherme, Roberta Santos; Meloni, Vera Ayres; Di Battista, Adriana; de Mello, Claudia Berlim; Bragagnolo, Silvia; Moretti-Ferreira, Danilo; Kosyakova, Nadezda; Liehr, Thomas; Carvalheira, Gianna Maria; Melaragno, Maria Isabel

    2015-12-01

    Detailed molecular characterization of chromosomal rearrangements involving X-chromosome has been a key strategy in identifying X-linked intellectual disability-causing genes. We fine-mapped the breakpoints in four women with balanced X-autosome translocations and variable phenotypes, in order to investigate the corresponding genetic contribution to intellectual disability. We addressed the impact of the gene interruptions in transcription and discussed the consequences of their functional impairment in neurodevelopment. Three patients presented with cognitive impairment, reinforcing the association between the disrupted genes (TSPAN7-MRX58, KIAA2022-MRX98, and IL1RAPL1-MRX21/34) and intellectual disability. While gene expression analysis showed absence of TSPAN7 and KIAA2022 expression in the patients, the unexpected expression of IL1RAPL1 suggested a fusion transcript ZNF611-IL1RAPL1 under the control of the ZNF611 promoter, gene disrupted at the autosomal breakpoint. The X-chromosomal breakpoint definition in the fourth patient, a woman with normal intellectual abilities, revealed disruption of the ZDHHC15 gene (MRX91). The expression assays did not detect ZDHHC15 gene expression in the patient, thus questioning its involvement in intellectual disability. Revealing the disruption of an X-linked intellectual disability-related gene in patients with balanced X-autosome translocation is a useful tool for a better characterization of critical genes in neurodevelopment. © 2015 Wiley Periodicals, Inc. PMID:26290131

  13. Molecular Evolution of Candidate Genes for Crop-Related Traits in Sunflower (Helianthus annuus L.)

    PubMed Central

    Mandel, Jennifer R.; McAssey, Edward V.; Nambeesan, Savithri; Garcia-Navarro, Elena; Burke, John M.

    2014-01-01

    Evolutionary analyses aimed at detecting the molecular signature of selection during crop domestication and/or improvement can be used to identify genes or genomic regions of likely agronomic importance. Here, we describe the DNA sequence-based characterization of a pool of candidate genes for crop-related traits in sunflower. These genes, which were identified based on homology to genes of known effect in other study systems, were initially sequenced from a panel of improved lines. All genes that exhibited a paucity of sequence diversity, consistent with the possible effects of selection during the evolution of cultivated sunflower, were then sequenced from a panel of wild sunflower accessions an outgroup. These data enabled formal tests for the effects of selection in shaping sequence diversity at these loci. When selection was detected, we further sequenced these genes from a panel of primitive landraces, thereby allowing us to investigate the likely timing of selection (i.e., domestication vs. improvement). We ultimately identified seven genes that exhibited the signature of positive selection during either domestication or improvement. Genetic mapping of a subset of these genes revealed co-localization between candidates for genes involved in the determination of flowering time, seed germination, plant growth/development, and branching and QTL that were previously identified for these traits in cultivated × wild sunflower mapping populations. PMID:24914686

  14. Non-essential genes in the vaccinia virus HindIII K fragment: a gene related to serine protease inhibitors and a gene related to the 37K vaccinia virus major envelope antigen.

    PubMed

    Boursnell, M E; Foulds, I J; Campbell, J I; Binns, M M

    1988-12-01

    The complete nucleotide sequence of a cloned copy of the HindIII K fragment of the WR strain of vaccinia virus has been determined. Eight open reading frames (ORFs) have been identified, on the basis of size and codon usage. The predicted amino acid sequences of the putative genes have been compared to the Protein Identification Resource and to published vaccinia virus sequences. One gene, predicted to encode a 42.2K protein, is highly related to the family of serine protease inhibitors. It shows approximately 25% identity to human antithrombin III and 19% identity to the cowpox virus 38K protein gene which is also related to serine protease inhibitors. The product of another gene shows a similar high level of identity to the 37K vaccinia virus major envelope antigen. The existence of viable deletion mutants and recombinants containing foreign DNA inserted into both these genes indicates that they are non-essential.

  15. HupO, a Novel Regulator Involved in Thiosulfate-Responsive Control of HupSL [NiFe]-Hydrogenase Synthesis in Thiocapsa roseopersicina

    PubMed Central

    Nagy, Ildikó K.; Kovács, Kornél L.

    2016-01-01

    [NiFe]-hydrogenases are regulated by various factors to fulfill their physiological functions in bacterial cells. The photosynthetic purple sulfur bacterium Thiocapsa roseopersicina harbors four functional [NiFe]-hydrogenases: HynSL, HupSL, Hox1, and Hox2. Most of these hydrogenases are functionally linked to sulfur metabolism, and thiosulfate has a central role in this organism. The membrane-associated Hup hydrogenases have been shown to play a role in energy conservation through hydrogen recycling. The expression of Hup-type hydrogenases is regulated by H2 in Rhodobacter capsulatus and Cupriavidus necator; however, it has been shown that the corresponding hydrogen-sensing system is nonfunctional in T. roseopersicina and that thiosulfate is a regulating factor of hup expression. Here, we describe the discovery and analysis of mutants of a putative regulator (HupO) of the Hup hydrogenase in T. roseopersicina. HupO appears to mediate the transcriptional repression of Hup enzyme synthesis under low-thiosulfate conditions. We also demonstrate that the presence of the Hox1 hydrogenase strongly influences Hup enzyme synthesis in that hup expression was decreased significantly in the hox1 mutant. This reduction in Hup synthesis could be reversed by mutation of hupO, which resulted in strongly elevated hup expression, as well as Hup protein levels, and concomitant in vivo hydrogen uptake activity in the hox1 mutant. However, this regulatory control was observed only at low thiosulfate concentrations. Additionally, weak hydrogen-dependent hup expression was shown in the hupO mutant strain lacking the Hox1 hydrogenase. HupO-mediated Hup regulation therefore appears to link thiosulfate metabolism and the hydrogenase network in T. roseopersicina. PMID:26801573

  16. Transcriptome expression analysis of candidate milk genes affecting cheese-related traits in 2 sheep breeds.

    PubMed

    Suárez-Vega, A; Gutiérrez-Gil, B; Arranz, J J

    2016-08-01

    Because ewe milk is principally used for cheese making, its quality is related to its content of total solids and the way in which milk constituents influence cheese yield and determine the technological and organoleptic characteristics of dairy products. Therefore, an in-depth knowledge of the expression levels of milk genes influencing cheese-related traits is essential. In the present study, the milk transcriptome data set of 2 dairy sheep breeds, Assaf and Spanish Churra, was used to evaluate the expression levels of 77 transcripts related to cheese yield and quality traits. For the comparison between both breeds, we selected the RNA sequencing (RNA-Seq) data at d 10 of lactation because this is the time point at which within and between breed differences due to lactation length are minimal. The evaluated genes encode major milk proteins (caseins and whey proteins), endogenous proteases, and enzymes related to fatty acid metabolism and citrate content. Through this analysis, we identified the genes predominantly expressed in each of the analyzed pathways that appear to be key genes for traits related to sheep milk cheese. Among the highly expressed genes in both breeds were the genes encoding caseins and whey proteins (CSN2, CSN3, CSN1S1, ENSOARG00000005099/PAEP, CSN1S2, LALBA), genes related to lipid metabolism (BTN1A1, XDH, FASN, ADFP, SCD, H-FABP, ACSS2), and one endogenous protease (CTSB). Moreover, a differential expression analysis between Churra and Assaf sheep allowed us to identify 7 genes that are significantly differentially expressed between the 2 breeds. These genes were mainly linked to endogenous protease activity (CTSL, CTSK, KLK10, KLK6, SERPINE2). Additionally, there were 2 differentially expressed genes coding for an intracellular fatty acid transporter (FABP4), an intermediate molecule of the citric acid cycle (SUCNR1), and 2 heat shock proteins (HSP70, HSPB8) that could be related to high protein production. The differential expression of

  17. Quantitative structure-activity relationships and docking studies of calcitonin gene-related peptide antagonists.

    PubMed

    Kyani, Anahita; Mehrabian, Mohadeseh; Jenssen, Håvard

    2012-02-01

    Defining the role of calcitonin gene-related peptide in migraine pathogenesis could lead to the application of calcitonin gene-related peptide antagonists as novel migraine therapeutics. In this work, quantitative structure-activity relationship modeling of biological activities of a large range of calcitonin gene-related peptide antagonists was performed using a panel of physicochemical descriptors. The computational studies evaluated different variable selection techniques and demonstrated shuffling stepwise multiple linear regression to be superior over genetic algorithm-multiple linear regression. The linear quantitative structure-activity relationship model revealed better statistical parameters of cross-validation in comparison with the non-linear support vector regression technique. Implementing only five peptide descriptors into this linear quantitative structure-activity relationship model resulted in an extremely robust and highly predictive model with calibration, leave-one-out and leave-20-out validation R(2) of 0.9194, 0.9103, and 0.9214, respectively. We performed docking of the most potent calcitonin gene-related peptide antagonists with the calcitonin gene-related peptide receptor and demonstrated that peptide antagonists act by blocking access to the peptide-binding cleft. We also demonstrated the direct contact of residues 28-37 of the calcitonin gene-related peptide antagonists with the receptor. These results are in agreement with the conclusions drawn from the quantitative structure-activity relationship model, indicating that both electrostatic and steric factors should be taken into account when designing novel calcitonin gene-related peptide antagonists. PMID:21974743

  18. Hormone therapy and maximal eccentric exercise alters myostatin-related gene expression in postmenopausal women.

    PubMed

    Dieli-Conwright, Christina M; Spektor, Tanya M; Rice, Judd C; Sattler, Fred R; Schroeder, E Todd

    2012-05-01

    We sought to evaluate baseline mRNA values and changes in gene expression of myostatin-related factors in postmenopausal women taking hormone therapy (HT) and not taking HT after eccentric exercise. Fourteen postmenopausal women participated including 6 controls not using HT (59 ± 4 years, 63 ± 17 kg) and 8 women using HT (59 ± 4 years, 89 ± 24 kg). The participants performed 10 sets of 10 maximal eccentric repetitions of single-leg extension on a dynamometer. Muscle biopsies from the vastus lateralis were obtained from the exercised leg at baseline and 4 hours after the exercise bout. Gene expression was determined using reverse transcriptase polymerase chain reaction for myostatin, activin receptor IIb (ActRIIb), follistatin, follistatin-related gene (FLRG), follistatin-like-3 (FSTL3), and GDF serum-associated protein-1 (GASP-1). In response to the exercise bout, myostatin and ActRIIb significantly decreased (p < 0.05), and follistatin, FLRG, FSTL3, and GASP-1 significantly increased in both groups (p < 0.05). Significantly greater changes in gene expression of all genes occurred in the HT group than in the control group after the acute eccentric exercise bout (p < 0.05). These data suggest that postmenopausal women using HT express greater myostatin-related gene expression, which may reflect a mechanism by which estrogen influences the preservation of muscle mass. Further, postmenopausal women using HT experienced a profoundly greater myostatin-related response to maximal eccentric exercise. PMID:22395277

  19. Dietary n-3 PUFA affect lipid metabolism and tissue function-related genes in bovine muscle.

    PubMed

    Hiller, Beate; Hocquette, Jean-Francois; Cassar-Malek, Isabelle; Nuernberg, Gerd; Nuernberg, Karin

    2012-09-01

    Gene expression profiles of bovine longissimus muscle as affected by dietary n-3 v. n-6 fatty acid (FA) intervention were analysed by microarray pre-screening of >3000 muscle biology/meat quality-related genes as well as subsequent quantitative RT-PCR gene expression validation of genes encoding lipogenesis-related transcription factors (CCAAT/enhancer-binding protein β, sterol regulatory element-binding transcription factor 1), key-lipogenic enzymes (acetyl-CoA carboxylase α (ACACA), fatty acid synthase (FASN), stearoyl-CoA desaturase (SCD)), lipid storage-associated proteins (adipose differentiation-related protein (ADFP)) and muscle biology-related proteins (cholinergic receptor, nicotinic, α1, farnesyl diphosphate farnesyl transferase 1, sema domain 3C (SEMA3C)). Down-regulation of ACACA (P = 0·00), FASN (P = 0·09) and SCD (P = 0·02) gene expression upon an n-3 FA intervention directly corresponded to reduced SFA, MUFA and total FA concentrations in longissimus muscle, whereas changes in ADFP (P = 0·00) and SEMA3C (P = 0·05) gene expression indicated improved muscle function via enhanced energy metabolism, vasculogenesis, innervation and mediator synthesis. The present study highlights the significance of dietary n-3 FA intervention on muscle development, maintenance and function, which are relevant for meat quality tailoring of bovine tissues and modulating animal production-relevant physiological processes.

  20. Corticosteroid receptor gene expression is related to sex and social behaviour in a social fish.

    PubMed

    O'Connor, Constance M; Rodela, Tammy M; Mileva, Viktoria R; Balshine, Sigal; Gilmour, Kathleen M

    2013-03-01

    Circulating corticosteroids have been related to social status in a variety of species. However, our understanding of corticosteroid receptor expression and its relationship with sociality is still in its infancy. Knowledge of variation in receptor expression is critical to understand the physiological relevance of differences in circulating corticosteroid concentrations. In this study, we examined corticosteroid receptor gene expression in relation to dominance rank, sex, and social behaviour in the highly social cichlid fish, Neolamprologus pulcher. We examined the relative gene expression of the three known teleost corticosteroid receptors: glucocorticoid receptor 1 (GR1), glucocorticoid receptor 2 (GR2), and the mineralocorticoid receptor (MR) in liver and brain tissue of dominant and subordinate N. pulcher males and females. Phylogenetic analysis revealed the N. pulcher gene originally described as GR2, clustered with other teleost GR1 genes, while the originally-described N. pulcher GR1 gene clustered with the GR2 genes of other teleosts. Therefore we propose a change in the original nomenclature of the N. pulcher GRs: GR1 (formerly GR2) and GR2 (formerly GR1) and adopt this new nomenclature throughout this manuscript. Liver MR transcript levels were higher in males than females, and positively related to submissive behaviour. Liver GR2 (formerly GR1) transcript levels were also higher in males than females. Collectively, the results demonstrate sex differences in corticosteroid receptor abundance, and suggest tissue- and receptor-specific roles for corticosteroid receptors in mediating aspects of social behaviour.

  1. Hydride bridge in [NiFe]-hydrogenase observed by nuclear resonance vibrational spectroscopy

    SciTech Connect

    Ogata, Hideaki; Krämer, Tobias; Wang, Hongxin; Schilter, David; Pelmenschikov, Vladimir; van Gastel, Maurice; Neese, Frank; Rauchfuss, Thomas B.; Gee, Leland B.; Scott, Aubrey D.; Yoda, Yoshitaka; Lubitz, Wolfgang; Cramer, Stephen P.

    2015-08-10

    The metabolism of many anaerobes relies on [NiFe]-hydrogenases, whose characterization when bound to substrates has proven non-trivial. Presented here is direct evidence for a hydride bridge in the active site of the 57Fe-labelled fully reduced Ni-R form of Desulfovibrio vulgaris Miyazaki F [NiFe]-hydrogenase. A unique ‘wagging’ mode involving H- motion perpendicular to the Ni(μ-H)57Fe plane was studied using 57Fe-specific nuclear resonance vibrational spectroscopy and density functional theory (DFT) calculations. On Ni(μ-D)57Fe deuteride substitution, this wagging causes a character