A mutant UW 3, which is unable to fix N 2 in the presence of Mo (Nif -) but undergo phenotypic reversal to Nif + under Mo deficiency, was able to grow in Mo- and NH 3-deficient medium containing Mn, and the growt...A mutant UW 3, which is unable to fix N 2 in the presence of Mo (Nif -) but undergo phenotypic reversal to Nif + under Mo deficiency, was able to grow in Mo- and NH 3-deficient medium containing Mn, and the growth was accelerated by Mn at low concentration. A partly purified nitrogenase component Ⅰ protein separated from UW 3 grown in the Mn-containing medium was shown to contain Fe and Mn atoms (ratio of Fe/Mo/Mn: 10.41/0.19/1.00) with C 2H 2- and H +-reducing activity which almost equal to half of that of MoFe protein purified from wild-type mutant of Azotobacter vinelandii Lipmann. This protein was obviously different from MoFe protein in both absorption spectrum and circular dichroism, and the molecular weight of subunits in Mn-containing protein was close to that of α subunit in MoFe protein. The preliminary results indicated that the protein containing Mn might be a nitrogenase component Ⅰ protein.展开更多
Nitrogenase CrFe protein and MnFe protein were purified from a mutant strain UW3 of Azotobacter vinelandii Lipmann grown on a medium containing Cr and Mn, respectively. In order to meet the requirement for crystal gro...Nitrogenase CrFe protein and MnFe protein were purified from a mutant strain UW3 of Azotobacter vinelandii Lipmann grown on a medium containing Cr and Mn, respectively. In order to meet the requirement for crystal growth Of O-2-susceptible proteins including nitrogenase in space, crystallization conditions were optimized for the proteins using a simple and suitable device, as a replacement for the cumbersome anaerobic box (dry box), for anaerobic addition of the protein samples. In all used precipitant and protein solutions added in the simplified plexi glass box, CrFe protein and MnFe protein could be crystallized on the spacecraft in one week by the liquid/liquid diffusion method and vapor diffusion by the sitting drop method, respectively. All formed crystals were single on the spacecraft, but under the same condition twin crystals appeared on the ground. The size of the largest crystal grown in space from CrFe protein was 2-fold larger than that on the ground. But the size of the largest crystal grown in space from MnFe protein was not larger than that on the ground. The difference in crystal growth in space between CrFe protein and MnFe protein could be resulted from the crystallization method, rather than the kind of protein.展开更多
Adult (ADS) and larva stages of palm weevil Rhynchophorus phoenicis were analyzed for their nutritional potentials using proximate and mineral contents as indices. The early larva stage (ELS) contains the highest mois...Adult (ADS) and larva stages of palm weevil Rhynchophorus phoenicis were analyzed for their nutritional potentials using proximate and mineral contents as indices. The early larva stage (ELS) contains the highest moisture content of 11.94% while ADS has the least value of 4.79%. The late larva stage (LLS) has the highest protein content of 10.51% while ADS contains 8.43%. Ash content is highest in ELS with a value of 2.37% and lowest in ADS with a value of 1.43%. ELS and LLS have the highest (22.14%) and lowest (17.22%) fibre contents respectively. The values of potassium, magnesium and iron in ELS were (455.00±21.21), (60.69±2.57) and (6.50±3.40) mg/kg while LLS recorded (457.50±10.61), (43.52±1.37) and (6.00±1.10) mg/kg and ADS recorded (372.50±24.75), (53.31±1.88) and (22.90±3.70) mg/kg. Chromium, phosphorus, nickel, calcium, lead, man- ganese and zinc were also detected. Copper was not detected in any of the samples. In all the developmental stages the protein solubilities were pH dependent with the minimum protein solubilities occurring at acidic pH while the maximum protein solu- bilities occurred at alkaline pH.展开更多
We estimated quantitative changes to the content of protein and cholesterol in the Haemolymph of adult Red Palm Weevil after being fed on sugar cane treatment with different concentrations of LeucokininlI. In males, 0...We estimated quantitative changes to the content of protein and cholesterol in the Haemolymph of adult Red Palm Weevil after being fed on sugar cane treatment with different concentrations of LeucokininlI. In males, 0.05% has recorded significant increase in total protein, then 0.25% concentration compeer control, while the maximum high of females 4.846 mg at 0.05% compeer control. The effect of leucokininlI on content of haemolymph cholesterol has shown result that 0.05% concentration and have a clear impact on cholesterol concentration for both sexes with an average reduction of 37.989 mg in males compeer with 120.123 for control, and 57.263 in females compeer with 96.087 mg for control.展开更多
The Deltanif E MoFe protein (Deltanif E Av1) was obtained by a chromatography on DE52, Sephacryl S-300 and Q-Sepharose columns from the unheated crude extract of nifE-deleted mutant strain (DJ35) of Azotobacter vinela...The Deltanif E MoFe protein (Deltanif E Av1) was obtained by a chromatography on DE52, Sephacryl S-300 and Q-Sepharose columns from the unheated crude extract of nifE-deleted mutant strain (DJ35) of Azotobacter vinelandii Lipmann. The analysis by SDS-PAGE showed that the Delta nif EAv1 was similar to OP MoFe protein (Av1) of A. vinelandii in the kinds and molecular weights of subunits (alpha and beta subunit). When complemented with nitrogenase Fe protein (M), the A nif EAv1 had hardly any proton-reduction activity, but could be significantly activated by FeMoco extracted from OP Av1. After the Delta nif E Av1 was treated with an excess o-phenanthroline (o-phen) and chromatographied on Sephadex G-25 column under atmosphere of Ar, Delta nif E Av1(C) was obtained. In the presence of both Av2 and MgATP regeneration system, the Delta nif EAv1(C), rather than A nif EAv1, was significantly activated in vitro by a reconstituent solution containing Mn which composed of KMnO4, ferric homocitrate, Na2S, Na2S2O4 (DT) and dithiothreitol (DTT). But in the absence of MgATP or Av2, the activation of Delta nifE Av1(C) did not happen. It indicates that activation of Delta nif EAv1 by RS-Mn requires the pretreatment with o-phen and the simultaneous presence of Av2 and MgATP.展开更多
Activating transcription factor 4 （ATF4） has been shown to play key roles in many physiological processes. There are no reports, however, demonstrating a direct link between ATF4 and lipid metabolism. We noticed tha...Activating transcription factor 4 （ATF4） has been shown to play key roles in many physiological processes. There are no reports, however, demonstrating a direct link between ATF4 and lipid metabolism. We noticed that Atf4- deficient mice are lean, suggesting a possible role for ATF4 in regulating lipid metabolism. The goal of our current study is to investigate the involvement of ATF4 in lipid metabolism and elucidate the underlying mechanisms. Studies using Atf4-deficient mice revealed increased energy expenditure, as measured by oxygen consumption. These mice also showed increases in lipolysis, expression of uncoupling protein 2 （UCP2） and p-oxidation genes and decreases in expression of lipogenic genes in white adipose tissue （WAT）, suggesting increased utilization and decreased synthesis of fatty acids, respectively. Expression of UCP1, 2 and 3 was also increased in brown adipose tissue （BAT）, suggesting increased thermogenesis. The effect of ATF4 deletion on expression of UCPs in BAT suggests that increased thermogenesis may underlie increased energy expenditure. Thus, our study identifies a possible new function for ATF4 in regulating lipid metabolism and thermogenesis.展开更多
Post-translational modifications are rapid, effective and reversible ways to regulate protein stability, localization, function, and their interactions with other molecules. Post-translational modifications usually oc...Post-translational modifications are rapid, effective and reversible ways to regulate protein stability, localization, function, and their interactions with other molecules. Post-translational modifications usually occur as chemical modifications at amino acid residues, including SUMOylation, phosphorylation, palmitoylation, acetylation, etc. These complex biochemical modifications tightly regulate and control a variety of cellular processes. Several forms of post-translational modifications of huntingtin （Htt） have been described. These modifications affect Htt metabolism, protein-protein interactions and cellular toxicity. Cleavage and clearance of mutant Htt, and the interactions between mutant Htt and other cellular proteins are important biochemical events leading to Huntington＇s disease （HD）. Therefore, identifying signaling pathways of Htt modification and evaluating the significance of Htt modifications would lead to a better understanding of the normal function of wild-type Htt and the pathogenic mechanisms of mutant Htt.展开更多
Protein palmitoylation is a widespread lipid modification in which one or more cysteine thiols on a substrate protein are modified to form a thioester with a palmitoyl group.This lipid modification is readily reversib...Protein palmitoylation is a widespread lipid modification in which one or more cysteine thiols on a substrate protein are modified to form a thioester with a palmitoyl group.This lipid modification is readily reversible;a feature of protein palmitoylation that allows for rapid regulation of the function of many cellular proteins.Mutations in palmitoyltransferases(PATs),the enzymes that catalyze the formation of this modification,are associated with a number of neurological diseases and cancer progression.This review summarizes the crucial role of palmitoylation in biological systems,the discovery of the DHHC protein family that catalyzes protein palmitoylation,and the development of methods for investigating the catalytic mechanism of PATs.展开更多
文摘A mutant UW 3, which is unable to fix N 2 in the presence of Mo (Nif -) but undergo phenotypic reversal to Nif + under Mo deficiency, was able to grow in Mo- and NH 3-deficient medium containing Mn, and the growth was accelerated by Mn at low concentration. A partly purified nitrogenase component Ⅰ protein separated from UW 3 grown in the Mn-containing medium was shown to contain Fe and Mn atoms (ratio of Fe/Mo/Mn: 10.41/0.19/1.00) with C 2H 2- and H +-reducing activity which almost equal to half of that of MoFe protein purified from wild-type mutant of Azotobacter vinelandii Lipmann. This protein was obviously different from MoFe protein in both absorption spectrum and circular dichroism, and the molecular weight of subunits in Mn-containing protein was close to that of α subunit in MoFe protein. The preliminary results indicated that the protein containing Mn might be a nitrogenase component Ⅰ protein.
文摘Nitrogenase CrFe protein and MnFe protein were purified from a mutant strain UW3 of Azotobacter vinelandii Lipmann grown on a medium containing Cr and Mn, respectively. In order to meet the requirement for crystal growth Of O-2-susceptible proteins including nitrogenase in space, crystallization conditions were optimized for the proteins using a simple and suitable device, as a replacement for the cumbersome anaerobic box (dry box), for anaerobic addition of the protein samples. In all used precipitant and protein solutions added in the simplified plexi glass box, CrFe protein and MnFe protein could be crystallized on the spacecraft in one week by the liquid/liquid diffusion method and vapor diffusion by the sitting drop method, respectively. All formed crystals were single on the spacecraft, but under the same condition twin crystals appeared on the ground. The size of the largest crystal grown in space from CrFe protein was 2-fold larger than that on the ground. But the size of the largest crystal grown in space from MnFe protein was not larger than that on the ground. The difference in crystal growth in space between CrFe protein and MnFe protein could be resulted from the crystallization method, rather than the kind of protein.
文摘Adult (ADS) and larva stages of palm weevil Rhynchophorus phoenicis were analyzed for their nutritional potentials using proximate and mineral contents as indices. The early larva stage (ELS) contains the highest moisture content of 11.94% while ADS has the least value of 4.79%. The late larva stage (LLS) has the highest protein content of 10.51% while ADS contains 8.43%. Ash content is highest in ELS with a value of 2.37% and lowest in ADS with a value of 1.43%. ELS and LLS have the highest (22.14%) and lowest (17.22%) fibre contents respectively. The values of potassium, magnesium and iron in ELS were (455.00±21.21), (60.69±2.57) and (6.50±3.40) mg/kg while LLS recorded (457.50±10.61), (43.52±1.37) and (6.00±1.10) mg/kg and ADS recorded (372.50±24.75), (53.31±1.88) and (22.90±3.70) mg/kg. Chromium, phosphorus, nickel, calcium, lead, man- ganese and zinc were also detected. Copper was not detected in any of the samples. In all the developmental stages the protein solubilities were pH dependent with the minimum protein solubilities occurring at acidic pH while the maximum protein solu- bilities occurred at alkaline pH.
文摘We estimated quantitative changes to the content of protein and cholesterol in the Haemolymph of adult Red Palm Weevil after being fed on sugar cane treatment with different concentrations of LeucokininlI. In males, 0.05% has recorded significant increase in total protein, then 0.25% concentration compeer control, while the maximum high of females 4.846 mg at 0.05% compeer control. The effect of leucokininlI on content of haemolymph cholesterol has shown result that 0.05% concentration and have a clear impact on cholesterol concentration for both sexes with an average reduction of 37.989 mg in males compeer with 120.123 for control, and 57.263 in females compeer with 96.087 mg for control.
文摘The Deltanif E MoFe protein (Deltanif E Av1) was obtained by a chromatography on DE52, Sephacryl S-300 and Q-Sepharose columns from the unheated crude extract of nifE-deleted mutant strain (DJ35) of Azotobacter vinelandii Lipmann. The analysis by SDS-PAGE showed that the Delta nif EAv1 was similar to OP MoFe protein (Av1) of A. vinelandii in the kinds and molecular weights of subunits (alpha and beta subunit). When complemented with nitrogenase Fe protein (M), the A nif EAv1 had hardly any proton-reduction activity, but could be significantly activated by FeMoco extracted from OP Av1. After the Delta nif E Av1 was treated with an excess o-phenanthroline (o-phen) and chromatographied on Sephadex G-25 column under atmosphere of Ar, Delta nif E Av1(C) was obtained. In the presence of both Av2 and MgATP regeneration system, the Delta nif EAv1(C), rather than A nif EAv1, was significantly activated in vitro by a reconstituent solution containing Mn which composed of KMnO4, ferric homocitrate, Na2S, Na2S2O4 (DT) and dithiothreitol (DTT). But in the absence of MgATP or Av2, the activation of Delta nifE Av1(C) did not happen. It indicates that activation of Delta nif EAv1 by RS-Mn requires the pretreatment with o-phen and the simultaneous presence of Av2 and MgATP.
文摘Activating transcription factor 4 （ATF4） has been shown to play key roles in many physiological processes. There are no reports, however, demonstrating a direct link between ATF4 and lipid metabolism. We noticed that Atf4- deficient mice are lean, suggesting a possible role for ATF4 in regulating lipid metabolism. The goal of our current study is to investigate the involvement of ATF4 in lipid metabolism and elucidate the underlying mechanisms. Studies using Atf4-deficient mice revealed increased energy expenditure, as measured by oxygen consumption. These mice also showed increases in lipolysis, expression of uncoupling protein 2 （UCP2） and p-oxidation genes and decreases in expression of lipogenic genes in white adipose tissue （WAT）, suggesting increased utilization and decreased synthesis of fatty acids, respectively. Expression of UCP1, 2 and 3 was also increased in brown adipose tissue （BAT）, suggesting increased thermogenesis. The effect of ATF4 deletion on expression of UCPs in BAT suggests that increased thermogenesis may underlie increased energy expenditure. Thus, our study identifies a possible new function for ATF4 in regulating lipid metabolism and thermogenesis.
基金supported by grants from the National Natural Science Foundation of China (No.30600197)
文摘Post-translational modifications are rapid, effective and reversible ways to regulate protein stability, localization, function, and their interactions with other molecules. Post-translational modifications usually occur as chemical modifications at amino acid residues, including SUMOylation, phosphorylation, palmitoylation, acetylation, etc. These complex biochemical modifications tightly regulate and control a variety of cellular processes. Several forms of post-translational modifications of huntingtin （Htt） have been described. These modifications affect Htt metabolism, protein-protein interactions and cellular toxicity. Cleavage and clearance of mutant Htt, and the interactions between mutant Htt and other cellular proteins are important biochemical events leading to Huntington＇s disease （HD）. Therefore, identifying signaling pathways of Htt modification and evaluating the significance of Htt modifications would lead to a better understanding of the normal function of wild-type Htt and the pathogenic mechanisms of mutant Htt.
基金financially supported by the NIH R01 grant GM040602 (CAF)
文摘Protein palmitoylation is a widespread lipid modification in which one or more cysteine thiols on a substrate protein are modified to form a thioester with a palmitoyl group.This lipid modification is readily reversible;a feature of protein palmitoylation that allows for rapid regulation of the function of many cellular proteins.Mutations in palmitoyltransferases(PATs),the enzymes that catalyze the formation of this modification,are associated with a number of neurological diseases and cancer progression.This review summarizes the crucial role of palmitoylation in biological systems,the discovery of the DHHC protein family that catalyzes protein palmitoylation,and the development of methods for investigating the catalytic mechanism of PATs.
