The hydration of olefins is one of the most im-portant processes for the production of alcohols[1].Ingeneral,the preparation methods using chiral organo-metallic complexes[2],microorganism[3]or cation-ex-changed montm...The hydration of olefins is one of the most im-portant processes for the production of alcohols[1].Ingeneral,the preparation methods using chiral organo-metallic complexes[2],microorganism[3]or cation-ex-changed montmorillonite[4]suffer from the drawbacks such as poor selectivity,separation difficulty or insta-bility.Enzymes as natural polymeric catalysts have attracted much attention in recent years due to their high activity and selectivity under mild condi-tions[5.6].In imitating the function of an enzyme,the use of natural biopolymers may be one of the ef-fective methods[7].Some natural biopolymer-metal complexes have been prepared and used as the catalyst for hydration to overcome the above disadvan-tages[8,9].Here we report the first results on the use of a wool-Pd complex for the asymmetric hydration of trans-2-butenoic acid.展开更多
Polactide(PLA),poly(3-hydroxybutyrate-co-4-hydroxybutyrate)(P(3HB-CO-4HB)),and poly(butylene adipate co-terephthalate)(PBAT)ternary blends were prepared by extrusion blending.The biodegradable PLA/P(3HB-co 4HB)/PBAT f...Polactide(PLA),poly(3-hydroxybutyrate-co-4-hydroxybutyrate)(P(3HB-CO-4HB)),and poly(butylene adipate co-terephthalate)(PBAT)ternary blends were prepared by extrusion blending.The biodegradable PLA/P(3HB-co 4HB)/PBAT films were successfully obtained by using blown films technique.Excellnt siffness-toughness balance was achieved for 55/10/35 PLA/P(3HB-co 4HB)/PBAT film.The tensile strength reached 33.0 MPa(MD)and 23.5 MPa(TD).the elongation at break exceeded 1309%,and tear strength exceeded 110 kN/m.The Young's modulus as low as about 1800 MPa also met packaging applications.SEM observations revealed rough and long ligaments,indicating that the tear specimens were broken yieldingly.The addition of PBAT elastomers was the main reason for the improved toughness of the film.From DMA and SEM analysis,it was demonstrated that PLA P(3HB co 4HB),and PBAT were prilly compatible.With increasing P(3HB CO-4HB)content,the melt and cold crstallization of PLA was promoted.The enzymatic degradation experiments indicated that the films had good biodegradability.These findings gave important implications for designing and manufacturing biodegradation package of high biological carbon content.展开更多
Poly(hydroxybutyrate)/poly(vinyl alcohol)(PHB/PVA)blends plasticized with glycerol were prepared by melt blending of PHB and glycerol plasticized PVA.The PHB/PVA-glycerol compositions were 90:10,75:25 and 50:50 w/w,be...Poly(hydroxybutyrate)/poly(vinyl alcohol)(PHB/PVA)blends plasticized with glycerol were prepared by melt blending of PHB and glycerol plasticized PVA.The PHB/PVA-glycerol compositions were 90:10,75:25 and 50:50 w/w,being the concentration of glycerol in the PVA mixture of 10 wt%.The blends were characterized by infrared spectroscopy,dynamic-mechanical thermal analysis,and scanning electron microscope of the fragile fractured surface.The results showed one single phase blend,indicating miscibility corroborated by the presence of a single glass transition temperature.The blending method proved to be an efficient way to tune PHB properties keeping its biodegradable nature since both PVA and glycerol are fully biodegradable materials.展开更多
The basic objective of this research is to determine the effects of acetate, propionate and butyrate on the biological phosphate(bio p) release and poly β hydroxybutyrate(PHB) synthesis and...The basic objective of this research is to determine the effects of acetate, propionate and butyrate on the biological phosphate(bio p) release and poly β hydroxybutyrate(PHB) synthesis and to test the effects of different acetate concentrations on the bio p release as well as the effect of butyrate on the bio p release and PHB synthesis in the presence of nitrates. Oxidation reduction potential probes are used to monitor the relative anaerobic and anoxic states of the sewage. The author quantified PHB, PHV in activated sludge by gas liquid chromatography. It has been demonstrated through a series of batch experiments that phosphorus release and PHB synthesis both take place in anaerobic zone of the bio p removal process, and the key factors to the maximization of PHB synthesis are that simple carbon substrates should be added to the anaerobic zone and that the addition of electron acceptors should be avoided.展开更多
the effects of exogenous Na -DL- 3 - hydroxybutyratc (3- HOBNa) and insulin (I)on skeletal muscle protein metabolism in rats infected with 37% TBSA full thickness scald werestudied. It was found that the serum acetoac...the effects of exogenous Na -DL- 3 - hydroxybutyratc (3- HOBNa) and insulin (I)on skeletal muscle protein metabolism in rats infected with 37% TBSA full thickness scald werestudied. It was found that the serum acetoacetatc (AcAc) of the burned animals showed nosignificant difference from the control on the 4th day postburn. but the free fatty acid (FFA) de-ereased markedly and the urinary 3 - methylhistidine (3 - MH ) excretion and the protein degrada-tion rate of the soleus muscle of the injured hind limb increased markedly. Infusion of3 - HOBNa for 3 consecutive days following bums could lower the urinary 3 - MH excretion andthe protein degradation rate of the soleus muscle with no significant influence on the skeletal muscleprotein anabolism. Moreover, investigations revealed that there was no synergistic effect ofinsulin -ketonc body combination on the anti- catabolic capacity in burned rats.展开更多
Studies on the miscibility of PHB/PELA blends showed that PHB and PELA were miscible in amorphous state.The crystallization behavior of PHB in the blend was strongly de- pendent on the addition of PELA component.
The poly(β-hydroxybutyrate)/poly(d,1-lactide)(PHB/PLA)blend was found to be immiscible,the melting point and the phase crystallinity of PHB were independent of the blend composition.Comparing with plain PHB,the blend...The poly(β-hydroxybutyrate)/poly(d,1-lactide)(PHB/PLA)blend was found to be immiscible,the melting point and the phase crystallinity of PHB were independent of the blend composition.Comparing with plain PHB,the blend exhibited the crystallization change and a certain improvement of the mechanical property.展开更多
Porous poly(3 hydroxybutyrate)(PHB) membranes were prepared by microemulsion templates. The influence of microemulsion templates on pore size and porosity of the PHB membranes were studied. Preliminary studies showed...Porous poly(3 hydroxybutyrate)(PHB) membranes were prepared by microemulsion templates. The influence of microemulsion templates on pore size and porosity of the PHB membranes were studied. Preliminary studies showed that the pore size made by microemulsion templates were smaller and were estimated in the range of 100~500 nanometer. In this research, the ultraviolet/visible light spectrometer was applied in the investigation of H 2O/Span85 Tween60/chloroform reserve microemulsion. Surfactant content(P) and water content(R) were optimized. Furthermore, the effects of variation of P and R on the pore size and porosity of PHB films were discussed.展开更多
Liver transplantation is oftentimes the last therapeutic resource for patients with late-stage chronic liver diseases,including cirrhosis and hepatocellular carcinoma.The liver's regenerative capacity is particula...Liver transplantation is oftentimes the last therapeutic resource for patients with late-stage chronic liver diseases,including cirrhosis and hepatocellular carcinoma.The liver's regenerative capacity is particularly critical following partial hepatectomy and transplantation.展开更多
Mitochondria,the cellular powerhouses,are dynamic organelles whose quality control is essential for maintaining cellular homeostasis,particularly under stress conditions such as oxidative damage or metabolic imbalance...Mitochondria,the cellular powerhouses,are dynamic organelles whose quality control is essential for maintaining cellular homeostasis,particularly under stress conditions such as oxidative damage or metabolic imbalance[1].Among the mechanisms ensuring mitochondrial integrity,mitochondrial-derived vesicles(MDVs)have emerged as a critical pathway for shuttling damaged components to lysosomes or the extracellular space,distinct from the more widely studied mitophagy[2,3].展开更多
Objective To investigate the effect of sodium hydroxybutyrate(GHB) on expression of hippocampal N-methyl-D-aspartate receptor 1 subunit (NR1) mRNA in the neonatal rat with hypoxic-ischemic insult. Methods One hundred ...Objective To investigate the effect of sodium hydroxybutyrate(GHB) on expression of hippocampal N-methyl-D-aspartate receptor 1 subunit (NR1) mRNA in the neonatal rat with hypoxic-ischemic insult. Methods One hundred eighty seven-day(7d) old Sprague Dawley rat pups of either sex weighting 10 g～14 g were randomly assigned to sham group(S), normal saline group(C),GHB 50 mg/kg group(γ50),GHB 100 mg/kg group(γ100)and GHB 200 mg/kg group(γ200),n=6.The procedure for the induction of hypoxia-ischemia was done according to the way described by Rice:under ether anesthesia,pups were subjected to left carotid artery ligated followed by 2 h of hypoxic exposure(O2:N2=8﹪:92﹪).The pups in S group were only aparted left carotid artery which was not obturated and no hypoxia.GHB 50 mg/kg, 100 mg/kg, 200 mg/kg was administered i.p immediately after hypoxia,then a time every 8h inγ50、γ100 and γ200 group respectively.The same volume normal saline was administered i.p in the same way in S and C group.Reverse transcriptase polymerase chain reaction(RT-PCR) was used to analyze the expression of NR1 mRNA semi-quantificationally in the left hippocampus at 2 h、6 h、12 h、1 d、3 d、7 d after insult in S、C、γ50、γ100 and γ200 group. Results The difference of expression of NR1 mRNA between S and C group wasn’t significant.At any time after insult, The differences of expression of NR1 mRNA among C and three GHB group were not significant too. Conclusion Hypoxia-ischemia and GHB didn’t significantly affect the expression of NR1 mRNA in neonatal rat hippocampus.展开更多
Aeromonas hydrophila 4AK4 was grown on mixed substrates of soybean oil and lauric acid for the production of polyhydroxyalkanoate copolymer consisting of 3 hydroxybutyrate (3HB) and 3 hydroxyhexanoate (3HHx). A m...Aeromonas hydrophila 4AK4 was grown on mixed substrates of soybean oil and lauric acid for the production of polyhydroxyalkanoate copolymer consisting of 3 hydroxybutyrate (3HB) and 3 hydroxyhexanoate (3HHx). A maximal poly(3 hydroxybutyrate co 3 hydroxyhexanoate) (PHBHHx) content of 49.13% in dry cells was obtained in a shake flask culture. PHBHHx of 6.26 g/L was produced in a fermentation experiment over 48 h on a sole carbon source containing 100 g/L soybean oil, while 12.40 g/L PHBHHx was produced on a mixed carbon source containing 80 g/L soybean and 20 g/L lauric acid over the same period of time, resulting in a polyhydroxyalkanoate (PHA) productivity of 0.25 g/(L·h). The results show that mixed carbon sources are suitable for industrialized production of PHBHHx from A. hydrophila 4AK4, as the mixed carbon sources also overcome the foaming problem that occurs when lauric acid is employed as a sole carbon source in PHBHHx production.展开更多
The phosphorus concentration in the culture medium affects the production of poly (3 hydroxybutyrate) (PHB) by Alcaligenes Eutrophus. This investigation shows that the phosphorus concentration in the initial culture m...The phosphorus concentration in the culture medium affects the production of poly (3 hydroxybutyrate) (PHB) by Alcaligenes Eutrophus. This investigation shows that the phosphorus concentration in the initial culture medium influences both the residual cell mass and the PHB production. A kinetic model is proposed for the production of PHB in a fedbatch culture of Alcaligenes Eutrophus. The kinetic model is compared with the experimental results and appears to provide an excellent description of the overall fermentation process. A phosphate mass concentration of 45 g/L produced the highest level of dry cell mass concentration (266 g/L), PHB mass concentration (214 g/L), PHB mass content (804%) and PHB productivity (351 g/L·h) so far obtained.展开更多
Synechocystis sp. PCC 6803 cell growth and poly β hydroxybutyrate (PHB) biosynthesis were studied in the presence of sodium acetate (NaAc). For nitrogen sufficient conditions, 15 mmol/L NaAc improved the PHB co...Synechocystis sp. PCC 6803 cell growth and poly β hydroxybutyrate (PHB) biosynthesis were studied in the presence of sodium acetate (NaAc). For nitrogen sufficient conditions, 15 mmol/L NaAc improved the PHB content up to 9.9% (w/w) while for nitrogen starved conditions, the PHB content was up to 15.2% (w/w). NaAc at levels below 20 mmol/L promoted cell growth in the first six days, but the growth slowed on the seventh day when the NaAc concentration exceeded 15 mmol/L. The PHB content in the final biomass reached 11.0% of the dry cellular weight in the presence of 20 mmol/L NaAc. Two adjacent open reading frames (ORFs) in the genome of Synechocystis sp. PCC 6803, slr1993 and slr1994, were assigned to phbA and phbB, respectively, while the phbC gene was found to be far from these genes. This may account for the low expression of PHB in cyanobacteria.展开更多
Aeromonas hydrophila (A. hydrophila) 4AK4 produced poly(3 hydroxybutyrate co 3 hydroxyhexanoate) (PHBHHx) with an almost constant 3 hydroxyhexanoate (3HHx) content of 10%15% from lauric acid and/or soybean oi...Aeromonas hydrophila (A. hydrophila) 4AK4 produced poly(3 hydroxybutyrate co 3 hydroxyhexanoate) (PHBHHx) with an almost constant 3 hydroxyhexanoate (3HHx) content of 10%15% from lauric acid and/or soybean oil. Both A. hydrophila 4AK4 and recombinant Escherichia coli (E. coli) JMU193 (pBH32) produced PHBHHx with controllable 3HHx content when fed lauric acid and another co substrate. With glucose or gluconate as the co substrate, the 3HHx content in the copolyester produced by A. hydrophila 4AK4 was reduced slightly from 12% to 9%. However, the 3HHx content in the copolyester produced by E. coli JMU193 (pBH32) was significantly reduced from 9% to 2% with fructose as the co substrate. These results show that regulation of 3HHx content in PHBHHx can be achieved using genetically engineered E. coli.展开更多
A plasmid (pTU9) containing the lambda (λ) phage lysis genes S( )RRz and the biosynthetic genes phb CAB of poly β hydroxybutyrate (PHB) was constructed and transformed into E.coli JM109. Cultured in Luria Ber...A plasmid (pTU9) containing the lambda (λ) phage lysis genes S( )RRz and the biosynthetic genes phb CAB of poly β hydroxybutyrate (PHB) was constructed and transformed into E.coli JM109. Cultured in Luria Bertani (LB) medium with 20 g/L glucose, E.coli JM109 (pTU9) could accumulate PHB in cells up to 40% (g PHB per g dry cells). A chelating agent EDTA was applied to induce a complete cell lysis and PHB granules were released. This method has a potential application in PHB separation.展开更多
Copolyesters of 3 hydroxybutyrate and 4 hydroxybutyrate along with terpolyesters of 3 hydroxybutyrate, 3 hydroxyvalerate and 4 hydroxybutyrate were produced using Alcaligenes latus DSM 1124 in growth media with p...Copolyesters of 3 hydroxybutyrate and 4 hydroxybutyrate along with terpolyesters of 3 hydroxybutyrate, 3 hydroxyvalerate and 4 hydroxybutyrate were produced using Alcaligenes latus DSM 1124 in growth media with precursors of 1,4 butanediol or 1,4 butanediol and valerate. Monomer mass fraction w in the copolyesters varied from 63% to 78% 3 hydroxybutyrate and 1 5% to 6 5% 4 hydroxybutyrate (cell dry weight), depending on precursor supplied. w(monomer) in the terpolyesters varied from 55% to 69% 3 hydroxybutyrate, 0 5% to 3 4% 4 hydroxybutyrate and 3 4% to 16% 3 hydroxyvalerate.展开更多
Polycystic ovary syndrome(PCOS)is a prevalent endocrine disorder among women of reproductive age,with a global prevalence ranging from 5%to 18%(Shrivastava and Conigliaro,2023).Currently,a total of 12.13 million cases...Polycystic ovary syndrome(PCOS)is a prevalent endocrine disorder among women of reproductive age,with a global prevalence ranging from 5%to 18%(Shrivastava and Conigliaro,2023).Currently,a total of 12.13 million cases of infertility(Liu et al.,2024)and 0.24 million cases of cardiovascular disease(Wan et al.,2024)are attributable to PCOS worldwide,and nearly 8 billion US dollars are spent in the USA and Europe for the management of PCOS every year.However,there are still many challenges in understanding and treatment of PCOS.展开更多
基金Supported by the Scholarship Foundation of Shanxi Province and the Natural Science Foundation of Shanxi Province(021109).
文摘The hydration of olefins is one of the most im-portant processes for the production of alcohols[1].Ingeneral,the preparation methods using chiral organo-metallic complexes[2],microorganism[3]or cation-ex-changed montmorillonite[4]suffer from the drawbacks such as poor selectivity,separation difficulty or insta-bility.Enzymes as natural polymeric catalysts have attracted much attention in recent years due to their high activity and selectivity under mild condi-tions[5.6].In imitating the function of an enzyme,the use of natural biopolymers may be one of the ef-fective methods[7].Some natural biopolymer-metal complexes have been prepared and used as the catalyst for hydration to overcome the above disadvan-tages[8,9].Here we report the first results on the use of a wool-Pd complex for the asymmetric hydration of trans-2-butenoic acid.
基金This work was financially supported by the fund of Science and Technology Bureau of Jilin Province of China(No.201702040125F)Chinese Academy of Sciences(Changchun Branch)(No.2020SYHZ0002)+1 种基金Science and Technology Services Network Program of Chinese Academy of Sciences(STS Project)(No.KFJ-STS-ZDTP-082)the National Science Foundation of Zhejiang Province of China(No.LQY19B040001).
文摘Polactide(PLA),poly(3-hydroxybutyrate-co-4-hydroxybutyrate)(P(3HB-CO-4HB)),and poly(butylene adipate co-terephthalate)(PBAT)ternary blends were prepared by extrusion blending.The biodegradable PLA/P(3HB-co 4HB)/PBAT films were successfully obtained by using blown films technique.Excellnt siffness-toughness balance was achieved for 55/10/35 PLA/P(3HB-co 4HB)/PBAT film.The tensile strength reached 33.0 MPa(MD)and 23.5 MPa(TD).the elongation at break exceeded 1309%,and tear strength exceeded 110 kN/m.The Young's modulus as low as about 1800 MPa also met packaging applications.SEM observations revealed rough and long ligaments,indicating that the tear specimens were broken yieldingly.The addition of PBAT elastomers was the main reason for the improved toughness of the film.From DMA and SEM analysis,it was demonstrated that PLA P(3HB co 4HB),and PBAT were prilly compatible.With increasing P(3HB CO-4HB)content,the melt and cold crstallization of PLA was promoted.The enzymatic degradation experiments indicated that the films had good biodegradability.These findings gave important implications for designing and manufacturing biodegradation package of high biological carbon content.
文摘Poly(hydroxybutyrate)/poly(vinyl alcohol)(PHB/PVA)blends plasticized with glycerol were prepared by melt blending of PHB and glycerol plasticized PVA.The PHB/PVA-glycerol compositions were 90:10,75:25 and 50:50 w/w,being the concentration of glycerol in the PVA mixture of 10 wt%.The blends were characterized by infrared spectroscopy,dynamic-mechanical thermal analysis,and scanning electron microscope of the fragile fractured surface.The results showed one single phase blend,indicating miscibility corroborated by the presence of a single glass transition temperature.The blending method proved to be an efficient way to tune PHB properties keeping its biodegradable nature since both PVA and glycerol are fully biodegradable materials.
文摘The basic objective of this research is to determine the effects of acetate, propionate and butyrate on the biological phosphate(bio p) release and poly β hydroxybutyrate(PHB) synthesis and to test the effects of different acetate concentrations on the bio p release as well as the effect of butyrate on the bio p release and PHB synthesis in the presence of nitrates. Oxidation reduction potential probes are used to monitor the relative anaerobic and anoxic states of the sewage. The author quantified PHB, PHV in activated sludge by gas liquid chromatography. It has been demonstrated through a series of batch experiments that phosphorus release and PHB synthesis both take place in anaerobic zone of the bio p removal process, and the key factors to the maximization of PHB synthesis are that simple carbon substrates should be added to the anaerobic zone and that the addition of electron acceptors should be avoided.
文摘the effects of exogenous Na -DL- 3 - hydroxybutyratc (3- HOBNa) and insulin (I)on skeletal muscle protein metabolism in rats infected with 37% TBSA full thickness scald werestudied. It was found that the serum acetoacetatc (AcAc) of the burned animals showed nosignificant difference from the control on the 4th day postburn. but the free fatty acid (FFA) de-ereased markedly and the urinary 3 - methylhistidine (3 - MH ) excretion and the protein degrada-tion rate of the soleus muscle of the injured hind limb increased markedly. Infusion of3 - HOBNa for 3 consecutive days following bums could lower the urinary 3 - MH excretion andthe protein degradation rate of the soleus muscle with no significant influence on the skeletal muscleprotein anabolism. Moreover, investigations revealed that there was no synergistic effect ofinsulin -ketonc body combination on the anti- catabolic capacity in burned rats.
基金The project was supported by the National Natural Science Foundation of China.
文摘Studies on the miscibility of PHB/PELA blends showed that PHB and PELA were miscible in amorphous state.The crystallization behavior of PHB in the blend was strongly de- pendent on the addition of PELA component.
文摘The poly(β-hydroxybutyrate)/poly(d,1-lactide)(PHB/PLA)blend was found to be immiscible,the melting point and the phase crystallinity of PHB were independent of the blend composition.Comparing with plain PHB,the blend exhibited the crystallization change and a certain improvement of the mechanical property.
文摘Porous poly(3 hydroxybutyrate)(PHB) membranes were prepared by microemulsion templates. The influence of microemulsion templates on pore size and porosity of the PHB membranes were studied. Preliminary studies showed that the pore size made by microemulsion templates were smaller and were estimated in the range of 100~500 nanometer. In this research, the ultraviolet/visible light spectrometer was applied in the investigation of H 2O/Span85 Tween60/chloroform reserve microemulsion. Surfactant content(P) and water content(R) were optimized. Furthermore, the effects of variation of P and R on the pore size and porosity of PHB films were discussed.
基金supported by services from the NIH center P30 DK120515(USA).
文摘Liver transplantation is oftentimes the last therapeutic resource for patients with late-stage chronic liver diseases,including cirrhosis and hepatocellular carcinoma.The liver's regenerative capacity is particularly critical following partial hepatectomy and transplantation.
基金supported by the National Key Research and Development Program of China(2022YFE0210100)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0480000)+6 种基金the National Natural Science Foundation projects of China(32371007,32025010,32488301,92254301,92357302,92157202,32241002,32261160376,and 32370782)the Major Project of Guangzhou National Laboratory(GZNL2024A03006)the Key Research Program,CAS(ZDBS-ZRKJZ-TLC003,YSBR-075 and 188GJHZ2024048GC)Guangdong Province Science and Technology Program(2023B0303000023,2023B1111050005,2023B1212060050,2023B1212120009,2024B1515040020,and 2024A1515030120)Guangzhou Science and Technology Program(202206060002 and 2025A04J5485)Health@InnoHK funding support from the Innovation Technology Commission of the Hong Kong SAR,and Major Research Project(GIBHMRP25-01)Basic Research Project of Guangzhou Institutes of Biomedicine and Health,Chinese Academy of Sciences.
文摘Mitochondria,the cellular powerhouses,are dynamic organelles whose quality control is essential for maintaining cellular homeostasis,particularly under stress conditions such as oxidative damage or metabolic imbalance[1].Among the mechanisms ensuring mitochondrial integrity,mitochondrial-derived vesicles(MDVs)have emerged as a critical pathway for shuttling damaged components to lysosomes or the extracellular space,distinct from the more widely studied mitophagy[2,3].
文摘Objective To investigate the effect of sodium hydroxybutyrate(GHB) on expression of hippocampal N-methyl-D-aspartate receptor 1 subunit (NR1) mRNA in the neonatal rat with hypoxic-ischemic insult. Methods One hundred eighty seven-day(7d) old Sprague Dawley rat pups of either sex weighting 10 g～14 g were randomly assigned to sham group(S), normal saline group(C),GHB 50 mg/kg group(γ50),GHB 100 mg/kg group(γ100)and GHB 200 mg/kg group(γ200),n=6.The procedure for the induction of hypoxia-ischemia was done according to the way described by Rice:under ether anesthesia,pups were subjected to left carotid artery ligated followed by 2 h of hypoxic exposure(O2:N2=8﹪:92﹪).The pups in S group were only aparted left carotid artery which was not obturated and no hypoxia.GHB 50 mg/kg, 100 mg/kg, 200 mg/kg was administered i.p immediately after hypoxia,then a time every 8h inγ50、γ100 and γ200 group respectively.The same volume normal saline was administered i.p in the same way in S and C group.Reverse transcriptase polymerase chain reaction(RT-PCR) was used to analyze the expression of NR1 mRNA semi-quantificationally in the left hippocampus at 2 h、6 h、12 h、1 d、3 d、7 d after insult in S、C、γ50、γ100 and γ200 group. Results The difference of expression of NR1 mRNA between S and C group wasn’t significant.At any time after insult, The differences of expression of NR1 mRNA among C and three GHB group were not significant too. Conclusion Hypoxia-ischemia and GHB didn’t significantly affect the expression of NR1 mRNA in neonatal rat hippocampus.
基金Supported by"985"Foundation of Tsinghua University
文摘Aeromonas hydrophila 4AK4 was grown on mixed substrates of soybean oil and lauric acid for the production of polyhydroxyalkanoate copolymer consisting of 3 hydroxybutyrate (3HB) and 3 hydroxyhexanoate (3HHx). A maximal poly(3 hydroxybutyrate co 3 hydroxyhexanoate) (PHBHHx) content of 49.13% in dry cells was obtained in a shake flask culture. PHBHHx of 6.26 g/L was produced in a fermentation experiment over 48 h on a sole carbon source containing 100 g/L soybean oil, while 12.40 g/L PHBHHx was produced on a mixed carbon source containing 80 g/L soybean and 20 g/L lauric acid over the same period of time, resulting in a polyhydroxyalkanoate (PHA) productivity of 0.25 g/(L·h). The results show that mixed carbon sources are suitable for industrialized production of PHBHHx from A. hydrophila 4AK4, as the mixed carbon sources also overcome the foaming problem that occurs when lauric acid is employed as a sole carbon source in PHBHHx production.
文摘The phosphorus concentration in the culture medium affects the production of poly (3 hydroxybutyrate) (PHB) by Alcaligenes Eutrophus. This investigation shows that the phosphorus concentration in the initial culture medium influences both the residual cell mass and the PHB production. A kinetic model is proposed for the production of PHB in a fedbatch culture of Alcaligenes Eutrophus. The kinetic model is compared with the experimental results and appears to provide an excellent description of the overall fermentation process. A phosphate mass concentration of 45 g/L produced the highest level of dry cell mass concentration (266 g/L), PHB mass concentration (214 g/L), PHB mass content (804%) and PHB productivity (351 g/L·h) so far obtained.
基金Supported by the National Natural Science F oundation of China (No.2 0 0 760 2 4)
文摘Synechocystis sp. PCC 6803 cell growth and poly β hydroxybutyrate (PHB) biosynthesis were studied in the presence of sodium acetate (NaAc). For nitrogen sufficient conditions, 15 mmol/L NaAc improved the PHB content up to 9.9% (w/w) while for nitrogen starved conditions, the PHB content was up to 15.2% (w/w). NaAc at levels below 20 mmol/L promoted cell growth in the first six days, but the growth slowed on the seventh day when the NaAc concentration exceeded 15 mmol/L. The PHB content in the final biomass reached 11.0% of the dry cellular weight in the presence of 20 mmol/L NaAc. Two adjacent open reading frames (ORFs) in the genome of Synechocystis sp. PCC 6803, slr1993 and slr1994, were assigned to phbA and phbB, respectively, while the phbC gene was found to be far from these genes. This may account for the low expression of PHB in cyanobacteria.
基金Supported by the National Natural Science Foundation of China (No. 2 0 0 74 0 2 0 ) and Tsinghua U niversity"985" Foundation
文摘Aeromonas hydrophila (A. hydrophila) 4AK4 produced poly(3 hydroxybutyrate co 3 hydroxyhexanoate) (PHBHHx) with an almost constant 3 hydroxyhexanoate (3HHx) content of 10%15% from lauric acid and/or soybean oil. Both A. hydrophila 4AK4 and recombinant Escherichia coli (E. coli) JMU193 (pBH32) produced PHBHHx with controllable 3HHx content when fed lauric acid and another co substrate. With glucose or gluconate as the co substrate, the 3HHx content in the copolyester produced by A. hydrophila 4AK4 was reduced slightly from 12% to 9%. However, the 3HHx content in the copolyester produced by E. coli JMU193 (pBH32) was significantly reduced from 9% to 2% with fructose as the co substrate. These results show that regulation of 3HHx content in PHBHHx can be achieved using genetically engineered E. coli.
文摘A plasmid (pTU9) containing the lambda (λ) phage lysis genes S( )RRz and the biosynthetic genes phb CAB of poly β hydroxybutyrate (PHB) was constructed and transformed into E.coli JM109. Cultured in Luria Bertani (LB) medium with 20 g/L glucose, E.coli JM109 (pTU9) could accumulate PHB in cells up to 40% (g PHB per g dry cells). A chelating agent EDTA was applied to induce a complete cell lysis and PHB granules were released. This method has a potential application in PHB separation.
文摘Copolyesters of 3 hydroxybutyrate and 4 hydroxybutyrate along with terpolyesters of 3 hydroxybutyrate, 3 hydroxyvalerate and 4 hydroxybutyrate were produced using Alcaligenes latus DSM 1124 in growth media with precursors of 1,4 butanediol or 1,4 butanediol and valerate. Monomer mass fraction w in the copolyesters varied from 63% to 78% 3 hydroxybutyrate and 1 5% to 6 5% 4 hydroxybutyrate (cell dry weight), depending on precursor supplied. w(monomer) in the terpolyesters varied from 55% to 69% 3 hydroxybutyrate, 0 5% to 3 4% 4 hydroxybutyrate and 3 4% to 16% 3 hydroxyvalerate.
基金supported by the National Key Research and Development Program of China(2021YFC2700403)Shanghai Municipal Science and Tech-nology Major Project(2023SHZDZX02)+1 种基金the National Natural Science Foundation of China(81873660 and 32371333)the Science and Technology Commission of Shanghai Municipality(23XD1423300 and 23ZR1411000).
文摘Polycystic ovary syndrome(PCOS)is a prevalent endocrine disorder among women of reproductive age,with a global prevalence ranging from 5%to 18%(Shrivastava and Conigliaro,2023).Currently,a total of 12.13 million cases of infertility(Liu et al.,2024)and 0.24 million cases of cardiovascular disease(Wan et al.,2024)are attributable to PCOS worldwide,and nearly 8 billion US dollars are spent in the USA and Europe for the management of PCOS every year.However,there are still many challenges in understanding and treatment of PCOS.
