Using all-atom molecular dynamics （MD） simulations, we have investigated the adsorption stability and conformation change of different proteins on the surface of pristine graphene （PG） and graphene oxide （GO）. W...Using all-atom molecular dynamics （MD） simulations, we have investigated the adsorption stability and conformation change of different proteins on the surface of pristine graphene （PG） and graphene oxide （GO）. We find that： （i） with the cooperation of the electrostatic interactions between proteins and oxygen-containing groups, GO shows better adsorption stability than PG; （ii） the peptide loses its secondary structure on both PG and GO surface, and the a-helix structure of the protein fragment is partially broken on PG surface, but is well preserved on GO surface, while the secondary structure of globular protein has no distinct change on both PG and GO surface. In general, GO presents better biocompatibility than PG. Our results are of significant importance to understand the interactions between proteins and PG/GO and the applications of PG/GO in biotechnology and biomedicine.展开更多
The objective of this study was to find highly nutritious native plants to feed cattle in northern Veracruz （Mexico） as an alternative to avoid deforestation for pasture establishment. Six fodder tree species （Leuc...The objective of this study was to find highly nutritious native plants to feed cattle in northern Veracruz （Mexico） as an alternative to avoid deforestation for pasture establishment. Six fodder tree species （Leucaena, Leucaenaleucocephala, Morera, Morus alba, Chacloco, rubiHamelia patents, Guficima, Guasumaulmifolia, Pichoco-bunting, Erythrinaamericana, Cocuite, Gliricidiasepium） were selected for their leave production, rapid growth and high nutritional quality. The plants were evaluated in the bud stage of senescence and flowering, restricting the fraction of mature foliage in the samples located under 2 meters height. Samples were collected from five plants per specie that were randomly selected. The nutritious parameters were evaluated through proximate analysis with the Van Soest technique. This study used a completely randomized design with five replicates. The nutritious composition showed PC （protein content） differences （P 〈 0.05） among species indicating that Leucaenaleucocephala （20%） had the lowest, Gliricidiasepium was （21%） intermediate and Morus alba （23%） had the highest. The FDN （neutral detergent fiber） and FDA （acid detergent） were lowest for Guasumaulmifolia （23.4%） and the other five species exceeded 40%. In conclusion, native foliage of fodder trees in northern, Veracruz are highly nutritious for cattle feeding and could alternative to avoid deforestation for pasture establishment to continue.展开更多
Highly efficient and rapid proteolytic digestion of proteins into peptides is a crucial step in shotgun-based proteome-analysis strategy. Tandem digestion by two or more proteases is demonstrated to be helpful for inc...Highly efficient and rapid proteolytic digestion of proteins into peptides is a crucial step in shotgun-based proteome-analysis strategy. Tandem digestion by two or more proteases is demonstrated to be helpful for increasing digestion efficiency and de- creasing missed cleavages, which results in more peptides that are compatible with mass-spectrometry analysis. Compared to conventional solution digestion, immobilized protease digestion has the obvious advantages of short digestion time, no self-proteolysis, and reusability. We proposed a multiple-immobilized proteases-digestion strategy that combines the ad- vantages of the two digestion strategies mentioned above. Graphene-oxide （GO）-based immobilized trypsin and endoprotein- ase Glu-C were prepared by covalently attaching them onto the GO surface. The prepared GO-trypsin and GO-Glu-C were successfully applied in standard protein digestion and multiple immobilized proteases digestion of total proteins of Thermoan- aerobacter tengcongensis. Compared to 12-hour solution digestion using trypsin or Glu-C, 14% and 7% improvement were obtained, respectively, in the sequence coverage of BSA by one-minute digestion using GO-trypsin and GO-GIu-C. Multiple immobilized-proteases digestion of the total proteins of Thermoanaerobacter tengcongensis showed 24.3% and 48.7% en- hancement in the numbers of identified proteins than was obtained using GO-trypsin or GO-Glu-C alone. The ultra-fast and highly efficient digestion can be contributed to the high loading capacity of protease on GO, which leads to fewer missed cleavages and more complete digestion. As a result, improved protein identification and sequence coverage can be expected.展开更多
基金supported by the National Natural Science Foundation of China(No.61575178 and No.11574272)the Zhejiang Provincial Natural Science Foundation of China(No.LY16A040014 and LY18A040001)the Scientific Research and Developed Fund of Zhejiang A&F University(No.2015FR022)
文摘Using all-atom molecular dynamics （MD） simulations, we have investigated the adsorption stability and conformation change of different proteins on the surface of pristine graphene （PG） and graphene oxide （GO）. We find that： （i） with the cooperation of the electrostatic interactions between proteins and oxygen-containing groups, GO shows better adsorption stability than PG; （ii） the peptide loses its secondary structure on both PG and GO surface, and the a-helix structure of the protein fragment is partially broken on PG surface, but is well preserved on GO surface, while the secondary structure of globular protein has no distinct change on both PG and GO surface. In general, GO presents better biocompatibility than PG. Our results are of significant importance to understand the interactions between proteins and PG/GO and the applications of PG/GO in biotechnology and biomedicine.
文摘The objective of this study was to find highly nutritious native plants to feed cattle in northern Veracruz （Mexico） as an alternative to avoid deforestation for pasture establishment. Six fodder tree species （Leucaena, Leucaenaleucocephala, Morera, Morus alba, Chacloco, rubiHamelia patents, Guficima, Guasumaulmifolia, Pichoco-bunting, Erythrinaamericana, Cocuite, Gliricidiasepium） were selected for their leave production, rapid growth and high nutritional quality. The plants were evaluated in the bud stage of senescence and flowering, restricting the fraction of mature foliage in the samples located under 2 meters height. Samples were collected from five plants per specie that were randomly selected. The nutritious parameters were evaluated through proximate analysis with the Van Soest technique. This study used a completely randomized design with five replicates. The nutritious composition showed PC （protein content） differences （P 〈 0.05） among species indicating that Leucaenaleucocephala （20%） had the lowest, Gliricidiasepium was （21%） intermediate and Morus alba （23%） had the highest. The FDN （neutral detergent fiber） and FDA （acid detergent） were lowest for Guasumaulmifolia （23.4%） and the other five species exceeded 40%. In conclusion, native foliage of fodder trees in northern, Veracruz are highly nutritious for cattle feeding and could alternative to avoid deforestation for pasture establishment to continue.
基金supported by the National Basic Research Program of China(2013CB911204)the National Key Scientific Instrument Development Program of China(2011YQ09000504)the National Natural Science Foundation of China(21275005,21235001)
文摘Highly efficient and rapid proteolytic digestion of proteins into peptides is a crucial step in shotgun-based proteome-analysis strategy. Tandem digestion by two or more proteases is demonstrated to be helpful for increasing digestion efficiency and de- creasing missed cleavages, which results in more peptides that are compatible with mass-spectrometry analysis. Compared to conventional solution digestion, immobilized protease digestion has the obvious advantages of short digestion time, no self-proteolysis, and reusability. We proposed a multiple-immobilized proteases-digestion strategy that combines the ad- vantages of the two digestion strategies mentioned above. Graphene-oxide （GO）-based immobilized trypsin and endoprotein- ase Glu-C were prepared by covalently attaching them onto the GO surface. The prepared GO-trypsin and GO-Glu-C were successfully applied in standard protein digestion and multiple immobilized proteases digestion of total proteins of Thermoan- aerobacter tengcongensis. Compared to 12-hour solution digestion using trypsin or Glu-C, 14% and 7% improvement were obtained, respectively, in the sequence coverage of BSA by one-minute digestion using GO-trypsin and GO-GIu-C. Multiple immobilized-proteases digestion of the total proteins of Thermoanaerobacter tengcongensis showed 24.3% and 48.7% en- hancement in the numbers of identified proteins than was obtained using GO-trypsin or GO-Glu-C alone. The ultra-fast and highly efficient digestion can be contributed to the high loading capacity of protease on GO, which leads to fewer missed cleavages and more complete digestion. As a result, improved protein identification and sequence coverage can be expected.
