A strain HB-03 to produce alkaline extracellular lipase was isolated from oil-rich soil samples and identified as Aspergillus awamori. The growth conditions and nutritional factors for lipase production by strain HB-0...A strain HB-03 to produce alkaline extracellular lipase was isolated from oil-rich soil samples and identified as Aspergillus awamori. The growth conditions and nutritional factors for lipase production by strain HB-03 were optimized, and the maximum lipase production of （45.9±2.3） U/mL was obtained at 30 ℃ and pH 7.0 after 36 h using olive oil （1%） and sucrose （0.5%） as carbon sources and combination of peptone （2%）, yeast extract （0.5%） and ammonium sulfate （0.1%） as nitrogen sources. The lipase was purified to homogeneity with 10.6-fold, 18.84% yield and a specific activity of 1 862.2 U/mg using ammonium sulfate precipitation followed by SephadexG-75 gel filtration chromatography. The purified lipase with molecular mass of 68 ku was estimated by SDS-PAGE. The optimum pH and temperature for the purified lipase were found to be 8.5 and 40 ℃, respectively. The lipase kept more than 80% of activity in pH 7.0-10.0 and temperatures up to 45 ℃. The metal ions of Mn2＋, Ba2＋ significantly enhanced the lipase activity, whereas Cu2＋, Fe3＋ and Mg2＋ strongly reduced the lipase activity. The Km and Vmax values of the purified enzyme for p-nitrophenyl palmitate were 0.13 mrnol/L and 60.6 mmol/（L.min）, respectively. The results show that this novel lipase has potential industrial applications.展开更多
OBJECTIVE Normal male aging is associated with declines in levels of the sex steroid hormone testosterone. A large body of evidence supports a neurotrophic role for testosterone in central nervous system. Lipoprotein ...OBJECTIVE Normal male aging is associated with declines in levels of the sex steroid hormone testosterone. A large body of evidence supports a neurotrophic role for testosterone in central nervous system. Lipoprotein lipase(LPL) is also expressed in the brain with highest levels found in the pyramidal cells of the hippocampus, we previous reported LPL-deficient mice exhibited memory disfunction. Testosterone is known to be largely converted to estradiol following aromatization within the hippocampus. Although testosterone has been implicated in lipid metabolism, it remains elusive whether testosterone can regulate brain LPL through DNA methylation mechanism. In order to clarify DNA methylation control exerted by testosterone over LPL gene in central nervous system, and its effect on lipid metabolism, we examined the adult male rat hippocampus to determine whether castration induced testosterone deficiency can affect lipid profile and LPL gene expression through its altered methylation pattern. METHODS Model of aging with declines in levels of the sex steroid hormone testosterone was performed as our previous description. RESULTS(1) Serum testosterone and brain testosterone levels were significantly decreased, which were restored to the control level after testosterone replacement,respectively(P<0.01);(2) Androgen deficiency was not found in Morris water maze and motor performance, however, androgen deficiency increases neurological and cognitive impairment in aged rats.(3)Decreased expression of olfactory marker protein(OMP) in olfactory bulb of SD rats treated with androgen deficiency.(4) The expression of Fox O3 and OMP in the olfactory bulb of androgen deficient rats was down-regulated, accompanied by dysfunction of the olfactory limbic system.(5) Decreased LPL m RNA level and inversely increased LPL promoter methylation level were observed following androgen deficiency and reserved by testosterone replacement.(6) In contrast, androgen deficiency slightly increased estrogen receptor beta(ERβ) m RNA levels and significantly decreased its promoter methylation levels within the hippocampus, and reserved as well by testosterone replacement. CONCLUSION(1) LPL in synaptic plasticity and contributes to a better understanding of the LPL function in the brain, where altered LPL levels are related to learning and memory impairment.(2) Androgen and Fox O3 play an important role in the olfactory cognitive process of the nervous system.(3) LPL expression in hippocampus is actively maintained by sex steroid hormones and that DNA methylation modification may contribute to this homeostatic regulation.展开更多
An environment friendly bio-surfactant of rhamnolipid(RL) was used as a solvent. The enzymatic reaction of oleic acid catalyzed by lipase and lignin peroxidase(lip) was evaluated. The optimum conditions of enzymatic r...An environment friendly bio-surfactant of rhamnolipid(RL) was used as a solvent. The enzymatic reaction of oleic acid catalyzed by lipase and lignin peroxidase(lip) was evaluated. The optimum conditions of enzymatic reaction catalyzed by lipase(lip) were water to amphiphile molar ratio of 30(20), RL of 60(60) critical micelle concentration(CMC), pH of 7.0(3.0) and temperature of 40(30) °C, respectively. The change of enzyme conformation indicates that, for catalytic of lipase, water content is the most important factor of the enzymatic reaction of oleic acid, and p H for lip. With individual optimum conditions, the enzymatic efficiency of oleic acid catalyzed by lipase is higher than that by lip. In the presence of ethanol, the enzymatic reaction of oleic acid catalyzed by lipase suits Ping-Pong Bi-Bi mechanism. As an alternative to chemical reversed micelles, the RL reversed micelles are promising methods to enzymatic reaction of oleic acid.展开更多
PVA/ Chitosan (CS) composite membrane was studied in this paper, which could be used for enzyme processing of fat and oils. The parameters such as concentration of lipase, pH, and cross-linking agent as well as metal ...PVA/ Chitosan (CS) composite membrane was studied in this paper, which could be used for enzyme processing of fat and oils. The parameters such as concentration of lipase, pH, and cross-linking agent as well as metal ions, which influence the immobilization of lipase in membrane, were optimized. The immobilized lipase was 0.66 u/cm2 and the recovery of immobilized lipase activity was 24%. The membrane reactor could be used to synthesize monoglyceride (MG) with many batches.展开更多
Apolipoprotein CⅢ(ApoCⅢ)has been implicated in hypertriglyceridemia and plasma ApoCⅢ is independently predicted as risk factor for coronary heart disease.Hypertriglyceridemia in patients are demonstrated to correla...Apolipoprotein CⅢ(ApoCⅢ)has been implicated in hypertriglyceridemia and plasma ApoCⅢ is independently predicted as risk factor for coronary heart disease.Hypertriglyceridemia in patients are demonstrated to correlate with elevated plasma ApoCⅢ levels and reduced lipoprotein lipase(LPL)activity,while展开更多
文摘A strain HB-03 to produce alkaline extracellular lipase was isolated from oil-rich soil samples and identified as Aspergillus awamori. The growth conditions and nutritional factors for lipase production by strain HB-03 were optimized, and the maximum lipase production of （45.9±2.3） U/mL was obtained at 30 ℃ and pH 7.0 after 36 h using olive oil （1%） and sucrose （0.5%） as carbon sources and combination of peptone （2%）, yeast extract （0.5%） and ammonium sulfate （0.1%） as nitrogen sources. The lipase was purified to homogeneity with 10.6-fold, 18.84% yield and a specific activity of 1 862.2 U/mg using ammonium sulfate precipitation followed by SephadexG-75 gel filtration chromatography. The purified lipase with molecular mass of 68 ku was estimated by SDS-PAGE. The optimum pH and temperature for the purified lipase were found to be 8.5 and 40 ℃, respectively. The lipase kept more than 80% of activity in pH 7.0-10.0 and temperatures up to 45 ℃. The metal ions of Mn2＋, Ba2＋ significantly enhanced the lipase activity, whereas Cu2＋, Fe3＋ and Mg2＋ strongly reduced the lipase activity. The Km and Vmax values of the purified enzyme for p-nitrophenyl palmitate were 0.13 mrnol/L and 60.6 mmol/（L.min）, respectively. The results show that this novel lipase has potential industrial applications.
基金NBRD Program of China(2016YFC1306302 2016YFC1305903)+3 种基金National Natural Science Foundation of China(81571044 81471633 61450004 and 81171015)
文摘OBJECTIVE Normal male aging is associated with declines in levels of the sex steroid hormone testosterone. A large body of evidence supports a neurotrophic role for testosterone in central nervous system. Lipoprotein lipase(LPL) is also expressed in the brain with highest levels found in the pyramidal cells of the hippocampus, we previous reported LPL-deficient mice exhibited memory disfunction. Testosterone is known to be largely converted to estradiol following aromatization within the hippocampus. Although testosterone has been implicated in lipid metabolism, it remains elusive whether testosterone can regulate brain LPL through DNA methylation mechanism. In order to clarify DNA methylation control exerted by testosterone over LPL gene in central nervous system, and its effect on lipid metabolism, we examined the adult male rat hippocampus to determine whether castration induced testosterone deficiency can affect lipid profile and LPL gene expression through its altered methylation pattern. METHODS Model of aging with declines in levels of the sex steroid hormone testosterone was performed as our previous description. RESULTS(1) Serum testosterone and brain testosterone levels were significantly decreased, which were restored to the control level after testosterone replacement,respectively(P<0.01);(2) Androgen deficiency was not found in Morris water maze and motor performance, however, androgen deficiency increases neurological and cognitive impairment in aged rats.(3)Decreased expression of olfactory marker protein(OMP) in olfactory bulb of SD rats treated with androgen deficiency.(4) The expression of Fox O3 and OMP in the olfactory bulb of androgen deficient rats was down-regulated, accompanied by dysfunction of the olfactory limbic system.(5) Decreased LPL m RNA level and inversely increased LPL promoter methylation level were observed following androgen deficiency and reserved by testosterone replacement.(6) In contrast, androgen deficiency slightly increased estrogen receptor beta(ERβ) m RNA levels and significantly decreased its promoter methylation levels within the hippocampus, and reserved as well by testosterone replacement. CONCLUSION(1) LPL in synaptic plasticity and contributes to a better understanding of the LPL function in the brain, where altered LPL levels are related to learning and memory impairment.(2) Androgen and Fox O3 play an important role in the olfactory cognitive process of the nervous system.(3) LPL expression in hippocampus is actively maintained by sex steroid hormones and that DNA methylation modification may contribute to this homeostatic regulation.
基金Projects(50978087,51009063,50978088)supported by the National Natural Science Foundation of China
文摘An environment friendly bio-surfactant of rhamnolipid(RL) was used as a solvent. The enzymatic reaction of oleic acid catalyzed by lipase and lignin peroxidase(lip) was evaluated. The optimum conditions of enzymatic reaction catalyzed by lipase(lip) were water to amphiphile molar ratio of 30(20), RL of 60(60) critical micelle concentration(CMC), pH of 7.0(3.0) and temperature of 40(30) °C, respectively. The change of enzyme conformation indicates that, for catalytic of lipase, water content is the most important factor of the enzymatic reaction of oleic acid, and p H for lip. With individual optimum conditions, the enzymatic efficiency of oleic acid catalyzed by lipase is higher than that by lip. In the presence of ethanol, the enzymatic reaction of oleic acid catalyzed by lipase suits Ping-Pong Bi-Bi mechanism. As an alternative to chemical reversed micelles, the RL reversed micelles are promising methods to enzymatic reaction of oleic acid.
文摘PVA/ Chitosan (CS) composite membrane was studied in this paper, which could be used for enzyme processing of fat and oils. The parameters such as concentration of lipase, pH, and cross-linking agent as well as metal ions, which influence the immobilization of lipase in membrane, were optimized. The immobilized lipase was 0.66 u/cm2 and the recovery of immobilized lipase activity was 24%. The membrane reactor could be used to synthesize monoglyceride (MG) with many batches.
文摘Apolipoprotein CⅢ(ApoCⅢ)has been implicated in hypertriglyceridemia and plasma ApoCⅢ is independently predicted as risk factor for coronary heart disease.Hypertriglyceridemia in patients are demonstrated to correlate with elevated plasma ApoCⅢ levels and reduced lipoprotein lipase(LPL)activity,while
