L'invention porte sur un procede pour la gestion de la concentration en ethanol pendant la fe... more L'invention porte sur un procede pour la gestion de la concentration en ethanol pendant la fermentation de gaz de synthese. Selon l'invention, un procede pour la fermentation de gaz de synthese comprend l'inoculation d'un milieu pour produire un milieu inocule. Le milieu inocule est mis en contact avec du gaz de synthese et les cellules et le milieu sont enleves et separes pour produire des cellules concentrees et un permeat. L'ethanol est separe du permeat pour produire de l'ethanol et un courant aqueux a teneur reduite en ethanol. Le courant aqueux a teneur reduite en ethanol est renvoye vers la fermentation.
La presente invention concerne des procedes de fermentation de substrat gazeux comprenant : l'... more La presente invention concerne des procedes de fermentation de substrat gazeux comprenant : l'addition d'un substrat gazeux a un milieu aqueux dans un bioreacteur. Les procedes de la presente invention comprennent : la mesure de la densite cellulaire ; l'ajustement de l'introduction de substrat gazeux pour augmenter la densite cellulaire ; la modification de la capture de CO specifique dans des quantites predeterminees.
L'invention concerne des procedes de fermentation de substrats gazeux selon lesquels on ajout... more L'invention concerne des procedes de fermentation de substrats gazeux selon lesquels on ajoute un substrat gazeux a un milieu aqueux dans un bioreacteur. Les procedes selon l'invention consistent notamment a mesurer la densite cellulaire, a regler l'apport de substrat gazeux afin d'augmenter la densite cellulaire et a modifier le captage de l'hydrogene.
ABSTRACTAn open reading frame in the genomic database ofMycobacterium tuberculosisH37Rv was ident... more ABSTRACTAn open reading frame in the genomic database ofMycobacterium tuberculosisH37Rv was identified as having homology with an outer membrane protein. We found that the gene specified a protein belonging to the OmpA family, which includes some porins of gram-negative organisms. The gene was amplified by PCR and cloned intoEscherichia coli. Overexpression of the gene was toxic to the host, but limited amounts could be purified from cells before growth ceased. A truncated gene devoid of the code for a presumed signal sequence was well expressed, but the protein had no pore-forming activity in the liposome swelling assay. However, the intact protein, OmpATb, behaved as a porin of low specific activity, with a pore diameter of 1.4 to 1.8 nm, and was also active in planar lipid bilayers, showing a single-channel conductance of 700 pS. The protein had a molecular mass of about 38 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A polyclonal rabbit antiserum raised to t...
Proceedings of the National Academy of Sciences, 2006
Sulfated molecules have been shown to modulate isotypic interactions between cells of metazoans a... more Sulfated molecules have been shown to modulate isotypic interactions between cells of metazoans and heterotypic interactions between bacterial pathogens or symbionts and their eukaryotic host cells.Mycobacterium tuberculosis, the causative agent of tuberculosis, produces sulfated molecules that have eluded functional characterization for decades. We demonstrate here that a previously uncharacterized sulfated molecule, termed S881, is localized to the outer envelope ofM. tuberculosisand negatively regulates the virulence of the organism in two mouse infection models. Furthermore, we show that the biosynthesis of S881 relies on the universal sulfate donor 3′-phosphoadenosine-5′-phosphosulfate and a previously uncharacterized sulfotransferase,stf3. These findings extend the known functions of sulfated molecules as general modulators of cell–cell interactions to include those between a bacterium and a human host.
Proceedings of the National Academy of Sciences, 2002
The study of the metabolome presents numerous challenges, first among them being the cataloging o... more The study of the metabolome presents numerous challenges, first among them being the cataloging of its constituents. A step in this direction will be the development of tools to identify metabolites that share common structural features. The importance of sulfated molecules in cell–cell communication motivated us to develop a rapid two-step method for identifying these metabolites in microorganisms, particularly in pathogenic mycobacteria. Sulfurcontaining molecules were initially identified by mass spectral analysis of cell extracts from bacteria labeled metabolically with a stable sulfur isotope ( 34 SO \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} \begin{equation*}_{4}^{2-}\end{equation*}\end{document} ). To differentiate sulfated from reduced-sulfur-containing molecules, we employed a mutant lacking the reductive branch...
L'invention porte sur un procede pour la gestion de la concentration en ethanol pendant la fe... more L'invention porte sur un procede pour la gestion de la concentration en ethanol pendant la fermentation de gaz de synthese. Selon l'invention, un procede pour la fermentation de gaz de synthese comprend l'inoculation d'un milieu pour produire un milieu inocule. Le milieu inocule est mis en contact avec du gaz de synthese et les cellules et le milieu sont enleves et separes pour produire des cellules concentrees et un permeat. L'ethanol est separe du permeat pour produire de l'ethanol et un courant aqueux a teneur reduite en ethanol. Le courant aqueux a teneur reduite en ethanol est renvoye vers la fermentation.
La presente invention concerne des procedes de fermentation de substrat gazeux comprenant : l'... more La presente invention concerne des procedes de fermentation de substrat gazeux comprenant : l'addition d'un substrat gazeux a un milieu aqueux dans un bioreacteur. Les procedes de la presente invention comprennent : la mesure de la densite cellulaire ; l'ajustement de l'introduction de substrat gazeux pour augmenter la densite cellulaire ; la modification de la capture de CO specifique dans des quantites predeterminees.
L'invention concerne des procedes de fermentation de substrats gazeux selon lesquels on ajout... more L'invention concerne des procedes de fermentation de substrats gazeux selon lesquels on ajoute un substrat gazeux a un milieu aqueux dans un bioreacteur. Les procedes selon l'invention consistent notamment a mesurer la densite cellulaire, a regler l'apport de substrat gazeux afin d'augmenter la densite cellulaire et a modifier le captage de l'hydrogene.
ABSTRACTAn open reading frame in the genomic database ofMycobacterium tuberculosisH37Rv was ident... more ABSTRACTAn open reading frame in the genomic database ofMycobacterium tuberculosisH37Rv was identified as having homology with an outer membrane protein. We found that the gene specified a protein belonging to the OmpA family, which includes some porins of gram-negative organisms. The gene was amplified by PCR and cloned intoEscherichia coli. Overexpression of the gene was toxic to the host, but limited amounts could be purified from cells before growth ceased. A truncated gene devoid of the code for a presumed signal sequence was well expressed, but the protein had no pore-forming activity in the liposome swelling assay. However, the intact protein, OmpATb, behaved as a porin of low specific activity, with a pore diameter of 1.4 to 1.8 nm, and was also active in planar lipid bilayers, showing a single-channel conductance of 700 pS. The protein had a molecular mass of about 38 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A polyclonal rabbit antiserum raised to t...
Proceedings of the National Academy of Sciences, 2006
Sulfated molecules have been shown to modulate isotypic interactions between cells of metazoans a... more Sulfated molecules have been shown to modulate isotypic interactions between cells of metazoans and heterotypic interactions between bacterial pathogens or symbionts and their eukaryotic host cells.Mycobacterium tuberculosis, the causative agent of tuberculosis, produces sulfated molecules that have eluded functional characterization for decades. We demonstrate here that a previously uncharacterized sulfated molecule, termed S881, is localized to the outer envelope ofM. tuberculosisand negatively regulates the virulence of the organism in two mouse infection models. Furthermore, we show that the biosynthesis of S881 relies on the universal sulfate donor 3′-phosphoadenosine-5′-phosphosulfate and a previously uncharacterized sulfotransferase,stf3. These findings extend the known functions of sulfated molecules as general modulators of cell–cell interactions to include those between a bacterium and a human host.
Proceedings of the National Academy of Sciences, 2002
The study of the metabolome presents numerous challenges, first among them being the cataloging o... more The study of the metabolome presents numerous challenges, first among them being the cataloging of its constituents. A step in this direction will be the development of tools to identify metabolites that share common structural features. The importance of sulfated molecules in cell–cell communication motivated us to develop a rapid two-step method for identifying these metabolites in microorganisms, particularly in pathogenic mycobacteria. Sulfurcontaining molecules were initially identified by mass spectral analysis of cell extracts from bacteria labeled metabolically with a stable sulfur isotope ( 34 SO \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} \begin{equation*}_{4}^{2-}\end{equation*}\end{document} ). To differentiate sulfated from reduced-sulfur-containing molecules, we employed a mutant lacking the reductive branch...
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Papers by Ryan Senaratne