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Rachael M Morgankiss - One of the best experts on this subject based on the ideXlab platform.
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the antarctic psychrophiles chlamydomonas spp uwo241 and ice mdv exhibit differential restructuring of photosystem i in response to iron
Photosynthesis Research, 2019Co-Authors: Greg Cook, Amber Grace Teufel, John C. Priscu, Isha Kalra, Xin Wang, Wei Li, Rachael M MorgankissAbstract:Chlamydomonas sp. UWO241 is a psychrophilic alga isolated from the deep photic zone of a perennially ice-covered Antarctic lake (east lobe Lake Bonney, ELB). Past studies have shown that C. sp. UWO241 exhibits constitutive downregulation of photosystem I (PSI) and high rates of PSI-associated cyclic electron flow (CEF). Iron levels in ELB are in the nanomolar range leading us to hypothesize that the unusual PSI phenotype of C. sp. UWO241 could be a response to chronic Fe-deficiency. We studied the impact of Fe availability in C. sp. UWO241, a Mesophile, C. reinhardtii SAG11-32c, as well as a psychrophile isolated from the shallow photic zone of ELB, Chlamydomonas sp. ICE-MDV. Under Fe-deficiency, PsaA abundance and levels of photooxidizable P700 (ΔA820/A820) were reduced in both psychrophiles relative to the Mesophile. Upon increasing Fe, C. sp. ICE-MDV and C. reinhardtii exhibited restoration of PSI function, while C. sp. UWO241 exhibited only moderate changes in PSI activity and lacked almost all LHCI proteins. Relative to Fe-excess conditions (200 µM Fe2+), C. sp. UWO241 grown in 18 µM Fe2+ exhibited downregulation of light harvesting and photosystem core proteins, as well as upregulation of a bestrophin-like anion channel protein and two CEF-associated proteins (NdsS, PGL1). Key enzymes of starch synthesis and shikimate biosynthesis were also upregulated. We conclude that in response to variable Fe availability, the psychrophile C. sp. UWO241 exhibits physiological plasticity which includes restructuring of the photochemical apparatus, increased PSI-associated CEF, and shifts in downstream carbon metabolism toward storage carbon and secondary stress metabolites.
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the antarctic psychrophiles chlamydomonas spp uwo241 and ice mdv exhibit differential restructuring of photosystem i in response to iron
Photosynthesis Research, 2019Co-Authors: Greg Cook, Amber Grace Teufel, John C. Priscu, Isha Kalra, Xin Wang, Wei Li, Rachael M MorgankissAbstract:Chlamydomonas sp. UWO241 is a psychrophilic alga isolated from the deep photic zone of a perennially ice-covered Antarctic lake (east lobe Lake Bonney, ELB). Past studies have shown that C. sp. UWO241 exhibits constitutive downregulation of photosystem I (PSI) and high rates of PSI-associated cyclic electron flow (CEF). Iron levels in ELB are in the nanomolar range leading us to hypothesize that the unusual PSI phenotype of C. sp. UWO241 could be a response to chronic Fe-deficiency. We studied the impact of Fe availability in C. sp. UWO241, a Mesophile, C. reinhardtii SAG11-32c, as well as a psychrophile isolated from the shallow photic zone of ELB, Chlamydomonas sp. ICE-MDV. Under Fe-deficiency, PsaA abundance and levels of photooxidizable P700 (ΔA820/A820) were reduced in both psychrophiles relative to the Mesophile. Upon increasing Fe, C. sp. ICE-MDV and C. reinhardtii exhibited restoration of PSI function, while C. sp. UWO241 exhibited only moderate changes in PSI activity and lacked almost all LHCI proteins. Relative to Fe-excess conditions (200 µM Fe2+), C. sp. UWO241 grown in 18 µM Fe2+ exhibited downregulation of light harvesting and photosystem core proteins, as well as upregulation of a bestrophin-like anion channel protein and two CEF-associated proteins (NdsS, PGL1). Key enzymes of starch synthesis and shikimate biosynthesis were also upregulated. We conclude that in response to variable Fe availability, the psychrophile C. sp. UWO241 exhibits physiological plasticity which includes restructuring of the photochemical apparatus, increased PSI-associated CEF, and shifts in downstream carbon metabolism toward storage carbon and secondary stress metabolites.
Benjamin C Sandman - One of the best experts on this subject based on the ideXlab platform.
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endotoxin structures in the psychrophiles psychromonas marina and psychrobacter cryohalolentis contain distinctive acyl features
Marine Drugs, 2014Co-Authors: Charles R Sweet, Giancarlo M Alpuche, Corinne A Landis, Benjamin C SandmanAbstract:Lipid A is the essential component of endotoxin (Gram-negative lipopolysaccharide), a potent immunostimulatory compound. As the outer surface of the outer membrane, the details of lipid A structure are crucial not only to bacterial pathogenesis but also to membrane integrity. This work characterizes the structure of lipid A in two psychrophiles, Psychromonas marina and Psychrobacter cryohalolentis, and also two Mesophiles to which they are related using MALDI-TOF MS and fatty acid methyl ester (FAME) GC-MS. P. marina lipid A is strikingly similar to that of Escherichia coli in organization and total acyl size, but incorporates an unusual doubly unsaturated tetradecadienoyl acyl residue. P. cryohalolentis also shows structural organization similar to a closely related Mesophile, Acinetobacter baumannii, however it has generally shorter acyl constituents and shows many acyl variants differing by single methylene (-CH2-) units, a characteristic it shares with the one previously reported psychrotolerant lipid A structure. This work is the first detailed structural characterization of lipid A from an obligate psychrophile and the second from a psychrotolerant species. It reveals distinctive structural features of psychrophilic lipid A in comparison to that of related Mesophiles which suggest constitutive adaptations to maintain outer membrane fluidity in cold environments.
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endotoxin structures in the psychrophiles psychromonas marina and psychrobacter cryohalolentis contain distinctive acyl features
Marine Drugs, 2014Co-Authors: Charles R Sweet, Giancarlo M Alpuche, Corinne A Landis, Benjamin C SandmanAbstract:Lipid A is the essential component of endotoxin (Gram-negative lipopolysaccharide), a potent immunostimulatory compound. As the outer surface of the outer membrane, the details of lipid A structure are crucial not only to bacterial pathogenesis but also to membrane integrity. This work characterizes the structure of lipid A in two psychrophiles, Psychromonas marina and Psychrobacter cryohalolentis, and also two Mesophiles to which they are related using MALDI-TOF MS and fatty acid methyl ester (FAME) GC-MS. P. marina lipid A is strikingly similar to that of Escherichia coli in organization and total acyl size, but incorporates an unusual doubly unsaturated tetradecadienoyl acyl residue. P. cryohalolentis also shows structural organization similar to a closely related Mesophile, Acinetobacter baumannii, however it has generally shorter acyl constituents and shows many acyl variants differing by single methylene (-CH2-) units, a characteristic it shares with the one previously reported psychrotolerant lipid A structure. This work is the first detailed structural characterization of lipid A from an obligate psychrophile and the second from a psychrotolerant species. It reveals distinctive structural features of psychrophilic lipid A in comparison to that of related Mesophiles which suggest constitutive adaptations to maintain outer membrane fluidity in cold environments.
Greg Cook - One of the best experts on this subject based on the ideXlab platform.
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the antarctic psychrophiles chlamydomonas spp uwo241 and ice mdv exhibit differential restructuring of photosystem i in response to iron
Photosynthesis Research, 2019Co-Authors: Greg Cook, Amber Grace Teufel, John C. Priscu, Isha Kalra, Xin Wang, Wei Li, Rachael M MorgankissAbstract:Chlamydomonas sp. UWO241 is a psychrophilic alga isolated from the deep photic zone of a perennially ice-covered Antarctic lake (east lobe Lake Bonney, ELB). Past studies have shown that C. sp. UWO241 exhibits constitutive downregulation of photosystem I (PSI) and high rates of PSI-associated cyclic electron flow (CEF). Iron levels in ELB are in the nanomolar range leading us to hypothesize that the unusual PSI phenotype of C. sp. UWO241 could be a response to chronic Fe-deficiency. We studied the impact of Fe availability in C. sp. UWO241, a Mesophile, C. reinhardtii SAG11-32c, as well as a psychrophile isolated from the shallow photic zone of ELB, Chlamydomonas sp. ICE-MDV. Under Fe-deficiency, PsaA abundance and levels of photooxidizable P700 (ΔA820/A820) were reduced in both psychrophiles relative to the Mesophile. Upon increasing Fe, C. sp. ICE-MDV and C. reinhardtii exhibited restoration of PSI function, while C. sp. UWO241 exhibited only moderate changes in PSI activity and lacked almost all LHCI proteins. Relative to Fe-excess conditions (200 µM Fe2+), C. sp. UWO241 grown in 18 µM Fe2+ exhibited downregulation of light harvesting and photosystem core proteins, as well as upregulation of a bestrophin-like anion channel protein and two CEF-associated proteins (NdsS, PGL1). Key enzymes of starch synthesis and shikimate biosynthesis were also upregulated. We conclude that in response to variable Fe availability, the psychrophile C. sp. UWO241 exhibits physiological plasticity which includes restructuring of the photochemical apparatus, increased PSI-associated CEF, and shifts in downstream carbon metabolism toward storage carbon and secondary stress metabolites.
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the antarctic psychrophiles chlamydomonas spp uwo241 and ice mdv exhibit differential restructuring of photosystem i in response to iron
Photosynthesis Research, 2019Co-Authors: Greg Cook, Amber Grace Teufel, John C. Priscu, Isha Kalra, Xin Wang, Wei Li, Rachael M MorgankissAbstract:Chlamydomonas sp. UWO241 is a psychrophilic alga isolated from the deep photic zone of a perennially ice-covered Antarctic lake (east lobe Lake Bonney, ELB). Past studies have shown that C. sp. UWO241 exhibits constitutive downregulation of photosystem I (PSI) and high rates of PSI-associated cyclic electron flow (CEF). Iron levels in ELB are in the nanomolar range leading us to hypothesize that the unusual PSI phenotype of C. sp. UWO241 could be a response to chronic Fe-deficiency. We studied the impact of Fe availability in C. sp. UWO241, a Mesophile, C. reinhardtii SAG11-32c, as well as a psychrophile isolated from the shallow photic zone of ELB, Chlamydomonas sp. ICE-MDV. Under Fe-deficiency, PsaA abundance and levels of photooxidizable P700 (ΔA820/A820) were reduced in both psychrophiles relative to the Mesophile. Upon increasing Fe, C. sp. ICE-MDV and C. reinhardtii exhibited restoration of PSI function, while C. sp. UWO241 exhibited only moderate changes in PSI activity and lacked almost all LHCI proteins. Relative to Fe-excess conditions (200 µM Fe2+), C. sp. UWO241 grown in 18 µM Fe2+ exhibited downregulation of light harvesting and photosystem core proteins, as well as upregulation of a bestrophin-like anion channel protein and two CEF-associated proteins (NdsS, PGL1). Key enzymes of starch synthesis and shikimate biosynthesis were also upregulated. We conclude that in response to variable Fe availability, the psychrophile C. sp. UWO241 exhibits physiological plasticity which includes restructuring of the photochemical apparatus, increased PSI-associated CEF, and shifts in downstream carbon metabolism toward storage carbon and secondary stress metabolites.
Charles R Sweet - One of the best experts on this subject based on the ideXlab platform.
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endotoxin structures in the psychrophiles psychromonas marina and psychrobacter cryohalolentis contain distinctive acyl features
Marine Drugs, 2014Co-Authors: Charles R Sweet, Giancarlo M Alpuche, Corinne A Landis, Benjamin C SandmanAbstract:Lipid A is the essential component of endotoxin (Gram-negative lipopolysaccharide), a potent immunostimulatory compound. As the outer surface of the outer membrane, the details of lipid A structure are crucial not only to bacterial pathogenesis but also to membrane integrity. This work characterizes the structure of lipid A in two psychrophiles, Psychromonas marina and Psychrobacter cryohalolentis, and also two Mesophiles to which they are related using MALDI-TOF MS and fatty acid methyl ester (FAME) GC-MS. P. marina lipid A is strikingly similar to that of Escherichia coli in organization and total acyl size, but incorporates an unusual doubly unsaturated tetradecadienoyl acyl residue. P. cryohalolentis also shows structural organization similar to a closely related Mesophile, Acinetobacter baumannii, however it has generally shorter acyl constituents and shows many acyl variants differing by single methylene (-CH2-) units, a characteristic it shares with the one previously reported psychrotolerant lipid A structure. This work is the first detailed structural characterization of lipid A from an obligate psychrophile and the second from a psychrotolerant species. It reveals distinctive structural features of psychrophilic lipid A in comparison to that of related Mesophiles which suggest constitutive adaptations to maintain outer membrane fluidity in cold environments.
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endotoxin structures in the psychrophiles psychromonas marina and psychrobacter cryohalolentis contain distinctive acyl features
Marine Drugs, 2014Co-Authors: Charles R Sweet, Giancarlo M Alpuche, Corinne A Landis, Benjamin C SandmanAbstract:Lipid A is the essential component of endotoxin (Gram-negative lipopolysaccharide), a potent immunostimulatory compound. As the outer surface of the outer membrane, the details of lipid A structure are crucial not only to bacterial pathogenesis but also to membrane integrity. This work characterizes the structure of lipid A in two psychrophiles, Psychromonas marina and Psychrobacter cryohalolentis, and also two Mesophiles to which they are related using MALDI-TOF MS and fatty acid methyl ester (FAME) GC-MS. P. marina lipid A is strikingly similar to that of Escherichia coli in organization and total acyl size, but incorporates an unusual doubly unsaturated tetradecadienoyl acyl residue. P. cryohalolentis also shows structural organization similar to a closely related Mesophile, Acinetobacter baumannii, however it has generally shorter acyl constituents and shows many acyl variants differing by single methylene (-CH2-) units, a characteristic it shares with the one previously reported psychrotolerant lipid A structure. This work is the first detailed structural characterization of lipid A from an obligate psychrophile and the second from a psychrotolerant species. It reveals distinctive structural features of psychrophilic lipid A in comparison to that of related Mesophiles which suggest constitutive adaptations to maintain outer membrane fluidity in cold environments.
Katsuhide Yutani - One of the best experts on this subject based on the ideXlab platform.
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stimulated interaction between α and β subunits of tryptophan synthase from hyperthermophile enhances its thermal stability
Journal of Biological Chemistry, 2003Co-Authors: Kyoko Ogasahara, Masami Ishida, Katsuhide YutaniAbstract:Tryptophan synthase from hyperthermophile, Pyrococcus furiosus, was found to be a tetrameric form (22) composed of and 2 subunits. To elucidate the relationship between the features of the subunit association and the thermal stability of the tryptophan synthase, the subunit association and thermal stability were examined by isothermal titration calorimetry and differential scanning calorimetry, respectively, in comparison with those of the counterpart from Escherichia coli. The association constants between the and subunits in the hyperthermophile protein were of the order of 108 M1, which were higher by two orders of magnitude than those in the Mesophile one. The negative values of the heat capacity change and enthalpy change upon the subunit association were much lower in the hyperthermophile protein than in the Mesophile one, indicating that the conformational change of the hyperthermophile protein coupled to the subunit association is slight. The denaturation temperature of the subunit from the hyperthermophile was enhanced by 17 degrees C due to the formation of the 22 complex. This increment in denaturation temperature due to complex formation could be quantitatively estimated by the increase in the association constant compared with that of the counterpart from E. coli.
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studies on interdomain interaction of 3 isopropylmalate dehydrogenase from an extreme thermophile thermus thermophilus by constructing chimeric enzymes
Extremophiles, 1999Co-Authors: Koichi Numata, Yoko Hayashiiwasaki, Katsuhide YutaniAbstract:In our previous study, we showed that a chimeric isopropylmalate dehydrogenase, 2T2M6T, between an extreme thermophile, Thermus thermophilus, and a Mesophile, Bacillus subtilis, isopropylmalate dehydrogenases (the name roughly denotes the primary structure; the first 20% from the N-terminal is coded by the thermophile leuB gene, next 20% by Mesophile, and the rest by the thermophile gene) denatured in two steps with a stable intermediate, suggesting that in the chimera some of the interdomain interaction was lost by amino acid substitutions in the "2M" part. To identify the residues involved in the interdomain interactions, the first and the second halves of the 2M part of the chimera were substituted with the corresponding sequence of the thermophile enzyme. Both chimeras, 3T1M6T and 2T1M7T, apparently showed one transition in the thermal denaturation without any stable intermediate state, suggesting that the cooperativity of the conformational stability was at least partly restored by the substitutions. The present study also suggested involvement of one or more basic residues in the unusual stability of the thermophile enzyme.