植物肌醇半乳糖苷合酶(galactinol synthase,GolS)是高等植物棉子糖类寡糖合成途径中的关键酶,为棉子糖系列寡糖提供活化的半乳糖基,调控植物体内棉子糖(raffinose,RFO)系列寡糖的生物合成与积累。编码该酶的基因属于糖基转移酶(glycosy...植物肌醇半乳糖苷合酶(galactinol synthase,GolS)是高等植物棉子糖类寡糖合成途径中的关键酶,为棉子糖系列寡糖提供活化的半乳糖基,调控植物体内棉子糖(raffinose,RFO)系列寡糖的生物合成与积累。编码该酶的基因属于糖基转移酶(glycosyltransferases,GTs)GT8基因家族的亚家族。GolS参与合成的最终产物棉子糖家族低聚糖(raffinose family oligosaccharides,RFOs)是植物中重要的碳水化合物存在形式,在细胞内可溶性强,可作为脱水保护剂;还能发挥稳定膜结构的作用。同时,GolS催化合成的直接产物肌醇半乳糖苷(galactinol)和RFOs都能作为羟基自由基捕获分子参与活性氧的清除。因此,GolS参与的代谢途径在植物碳同化物的贮存与运输、生物和非生物逆境响应、种子的脱水效应等生命过程中均发挥了重要作用。GolS基因结构差异与表达模式不同,导致不同GolS基因参与的生物学功能具有很大的差异。研究植物中不同GolS基因的结构特征,组织特异性表达特性及它们响应不同生长发育阶段、环境变化的表达特性,对了解GolS参与的生物学功能具有重要意义。同时,在分子生物学水平上,深入了解调控植物GolS基因的分子调控机制,为通过遗传工程或分子辅助育种等手段,利用GolS改良农林作物的经济性状提供理论支持。本文针对近年来植物中GolS基因的生理功能和调控机制的研究进行了综述。展开更多
AIM： To observe the curative effect of galactosylated chitosan （GC）/5-fluorouracil （5-FU） nanoparticles in liver caner mice and its side effects. METHODS： The GC/5-FU nanoparticle is a nanomate- rial made by cou...AIM： To observe the curative effect of galactosylated chitosan （GC）/5-fluorouracil （5-FU） nanoparticles in liver caner mice and its side effects. METHODS： The GC/5-FU nanoparticle is a nanomate- rial made by coupling GC and 5-FU. The release experiment was performed in vitro. The orthotropic liver cancer mouse models were established and divided into control, GC, 5-FU and GC/5-FU groups. Mice in the control and GC group received an intravenous injection of 200 μL saline and GC, respectively. Mice in the 5-FU and GC/5-FU groups received 200 μL （containing 0.371 mg 5-FU） 5-FU and GC/5-FU, respectively. The tumor weight and survival time were observed. The cell cycle and apoptosis in tumor tissues were monitored by flow cytometry. The expression of p53, Bax, Bcl-2, caspase-3 and poly adenosine 50-diphosphate-ribose polymerase 1 （PARP-1） was detected by immunohistochemistry, reverse transcription-polymerase chain reaction and Western blot. The serum blood biochemical parameters and cytotoxic activity of natural killer （NK） cell and cy- totoxicity T lymphocyte （CTL） were measured. RESULTS： The GC/5-FU nanoparticle is a sustained release system. The drug loading was 6.12% ± 1.36%, the encapsulation efficiency was 81.82% ± 5.32%, and the Zeta potential was 10.34 ± 1.43 mV. The tu- mor weight in the GC/5-FU group （0.4361±0.1153 g vs 1.5801 ± 0.2821 g, P 〈 0.001） and the 5-FU （0.7932±0.1283 g vs 1.5801 ±0.2821 g, P 〈 0.001） was sig- nificantly lower than that in the control group; GC/5- FU treatment can significantly lower the tumor weight （0.4361± 0.1153 g vs 0.7932±0.1283 g, P 〈 0.001）, and the longest median survival time was seen in the GC/5-FU group, compared with the control （12 d vs 30 d, P 〈 0.001）, GC （13 d vs 30 d, P 〈 0.001） and 5-FU groups （17 d vs 30 d, P 〈 0.001）. Flow cytom- etry revealed that compared with the control, GC/5- FU caused a higher rate of G0-G1 arrest （52.79% ± 13.42% vs 23.92%±9.09%, P = 0.014 ） and apopto- sis （2.55% ±1.10% vs 11.13% ±11.73%, P 〈 0.001） in hepatic cancer cells. Analysis of the apoptosis path- ways showed that GC/5-FU upregulated the expression of p53 at both the protein and the mRNA levels, which in turn lowered the ratio of Bcl-2lBax expression; this led to the release of cytochrome C into the cytosol from the mitochondria and the subsequent activation of caspase-3. Upregulation of caspase-3 expression de- creased the PARP-1 at both the mRNA and the protein levels, which contributed to apoptosis. 5-FU increased the levels of aspartate aminotransferase and alanine aminotransferase, and decreased the numbers of platelet, white blood cell and lymphocyte and cytotoxic activities of CTL and NK cells, however, there were no such side effects in the GC/5-FU group. CONCLUSION： GC/5-FU nanoparticles can significant- ly inhibit the growth of liver cancer in mice via the p53 apoptosis pathway, and relieve the side effects and im- munosuppression of 5-FU.展开更多
Methyl-galactosides were oxidized at room temperature by galactose oxidase in a one-step reaction and afforded methyl-galactoaldehyde in excellent yield and high purity. The resulting galactoaldehyde as a useful inter...Methyl-galactosides were oxidized at room temperature by galactose oxidase in a one-step reaction and afforded methyl-galactoaldehyde in excellent yield and high purity. The resulting galactoaldehyde as a useful intermediate can be directly used in glycopeptide synthesis.展开更多
AIM:To study the effects of live and dead Lactobacillus rhamnosus GG(GG) on rotavirus infection in a neonatal rat model.METHODS:At the age of 2 d,suckling Lewis rat pups were supplemented with either live or dead GG a...AIM:To study the effects of live and dead Lactobacillus rhamnosus GG(GG) on rotavirus infection in a neonatal rat model.METHODS:At the age of 2 d,suckling Lewis rat pups were supplemented with either live or dead GG and the treatment was continued daily throughout the experi-ment.At the age of 5 and 6 d the pups received oral rotavirus(RV) SA-11 strain.The pups were sacrificed at the age of 7 or 8 d by decapitation.The gastrointestinal tract was removed and macroscopic observations were done.The consistency of feces in the colon was classified using a four-tier system.RV was detected from the plasma,small intestine,colon and feces by real-time quantitative polymerase chain reaction(PCR).RESULTS:In this neonatal rat model,RV induced a mild-to-moderate diarrhea in all except one pup of the RV-inoculated rats.RV moderately reduced body weight development from day 6 onwards.On day 7,after 2 d of RV infection,live and dead GG groups gained significantly more weight than the RV group without probiotics [36%(P = 0.001) and 28%(P = 0.031),respectively].In addition,when compared with the RV control group,both live and dead GG reduced the weight ratio of colon/animal body weight to the same level as in the healthy control group,with reductions of 22%(P = 0.002) and 28%(P < 0.001),respectively.Diarrhea increased moderately in both GG groups.However,the diarrhea incidence and severity in the GG groups were not statistically significantly different as compared with the RV control group.Moreover,observed diarrhea did not provoke weight loss or death.The RV control group had the largest amount of RV PCR-positive samples among the RV-infected groups,and the live GG group had the smallest amount.Rats receiving live GG had significantly less RV in the colon(P = 0.027) when compared with the RV control group.Live GG was also more effective over dead GG in reducing the quantity of RV from plasma(P = 0.047).CONCLUSION:Both live and dead GG have beneficial effects in RV infection.GG may increase RV clearance from the body and reduce colon swelling.展开更多
The apple rootstock, A106 (Malus sieboldii), had 17 bivalents in pollen mother cells at meiotic metaphase 1,and 17 chromosomes in a haploid pollen cell. Karyotypes were prepared from root-tip cells with 2n= 34 chromos...The apple rootstock, A106 (Malus sieboldii), had 17 bivalents in pollen mother cells at meiotic metaphase 1,and 17 chromosomes in a haploid pollen cell. Karyotypes were prepared from root-tip cells with 2n= 34 chromosomes. Seven out of 82 karyotypes (8.5%) showed one pair of satellites at the end of the short arm of chromosome 3. C-bands were shown on 6 pairs of chromosomes 2, 4,6, 8, 14, and 16 near the telomeric regions of short arms.Probes for three ripening-related genes from Malus x domestica: endopolygalacturonase (EPG,0. 6 kb ) , ACC oxidase (1.2 kb), and ACC synthase (2 kb) were hybridized in situ to metaphase chromosomes of A106. Hybridization sites for the EPG gene were observed on the long arm of chromosome 14 in 15 out of 16 replicate spreads and proximal to the centromere of chromosomes 6 and 11. For the ACC oxidase gene, hybridization sites were observed in the telomeric region of the short arm of chromosomes 5 and 11 in 87% and 81% of 16 spreads respectively proximal to the centromere of chromosome 1 in 81% of the spreads, and on the long arm of chromosome 13 in 50% of the spreads. Twenty five spreads were studied for the ACC synthase gene and hybridization sites were observed in the telomeric region of the short arm of chromosome 12 in 96% of the spreads, chromosomes 9 and 10 in 76% of the spreads, and chromosome 17 in 56% of the spreads.展开更多
Nucleoside phosphorylase is an important enzyme involved in the biosynthesis of nucleosides. In this study, purine nucleoside phosphorylase and pyrimidine nucleoside phosphorylase were co-expressed in Escherichia coli...Nucleoside phosphorylase is an important enzyme involved in the biosynthesis of nucleosides. In this study, purine nucleoside phosphorylase and pyrimidine nucleoside phosphorylase were co-expressed in Escherichia coli and the intact cells were used as a catalyst for the biosynthesis of nucleosides. For protein induction, lactose was used in place of isopropyl β-D-l-thiogalactopyranoside （IPTG）. When the concentration of lactose was above 0.5 mmol/L, the ability to induce protein expression was similar to that of IPTG. We determined that the reaction conditions of four bacterial strains co-expressing these genes （TUD, TAD, DUD, and DAD） were similar for the biosyntheses of 2,6-diaminopurine nucleoside and 2,6-diaminopurine deoxynucleoside. When the substrate concentration was 30 mmol/L and 0.5% of the recombinant bacterial cell volume was used as the catalyst （pH 7.5）, a greater than 90% conversion yield was reached after a 2-h incubation at 50℃. In addition, several other nucleosides and nucleoside derivatives were efficiently synthesized using bacterial strains co-expressing these recombinant enzymes.展开更多
文摘植物肌醇半乳糖苷合酶(galactinol synthase,GolS)是高等植物棉子糖类寡糖合成途径中的关键酶,为棉子糖系列寡糖提供活化的半乳糖基,调控植物体内棉子糖(raffinose,RFO)系列寡糖的生物合成与积累。编码该酶的基因属于糖基转移酶(glycosyltransferases,GTs)GT8基因家族的亚家族。GolS参与合成的最终产物棉子糖家族低聚糖(raffinose family oligosaccharides,RFOs)是植物中重要的碳水化合物存在形式,在细胞内可溶性强,可作为脱水保护剂;还能发挥稳定膜结构的作用。同时,GolS催化合成的直接产物肌醇半乳糖苷(galactinol)和RFOs都能作为羟基自由基捕获分子参与活性氧的清除。因此,GolS参与的代谢途径在植物碳同化物的贮存与运输、生物和非生物逆境响应、种子的脱水效应等生命过程中均发挥了重要作用。GolS基因结构差异与表达模式不同,导致不同GolS基因参与的生物学功能具有很大的差异。研究植物中不同GolS基因的结构特征,组织特异性表达特性及它们响应不同生长发育阶段、环境变化的表达特性,对了解GolS参与的生物学功能具有重要意义。同时,在分子生物学水平上,深入了解调控植物GolS基因的分子调控机制,为通过遗传工程或分子辅助育种等手段,利用GolS改良农林作物的经济性状提供理论支持。本文针对近年来植物中GolS基因的生理功能和调控机制的研究进行了综述。
基金Supported by Natural Science Foundation of Shanghai,No.09ZR1424700 and 114119a4700Minhang District Natural Science Foundation of Shanghai,No. 2009MHZ085grants from Minhang District Public Health Bureau of Shanghai,No.2009MW28
文摘AIM： To observe the curative effect of galactosylated chitosan （GC）/5-fluorouracil （5-FU） nanoparticles in liver caner mice and its side effects. METHODS： The GC/5-FU nanoparticle is a nanomate- rial made by coupling GC and 5-FU. The release experiment was performed in vitro. The orthotropic liver cancer mouse models were established and divided into control, GC, 5-FU and GC/5-FU groups. Mice in the control and GC group received an intravenous injection of 200 μL saline and GC, respectively. Mice in the 5-FU and GC/5-FU groups received 200 μL （containing 0.371 mg 5-FU） 5-FU and GC/5-FU, respectively. The tumor weight and survival time were observed. The cell cycle and apoptosis in tumor tissues were monitored by flow cytometry. The expression of p53, Bax, Bcl-2, caspase-3 and poly adenosine 50-diphosphate-ribose polymerase 1 （PARP-1） was detected by immunohistochemistry, reverse transcription-polymerase chain reaction and Western blot. The serum blood biochemical parameters and cytotoxic activity of natural killer （NK） cell and cy- totoxicity T lymphocyte （CTL） were measured. RESULTS： The GC/5-FU nanoparticle is a sustained release system. The drug loading was 6.12% ± 1.36%, the encapsulation efficiency was 81.82% ± 5.32%, and the Zeta potential was 10.34 ± 1.43 mV. The tu- mor weight in the GC/5-FU group （0.4361±0.1153 g vs 1.5801 ± 0.2821 g, P 〈 0.001） and the 5-FU （0.7932±0.1283 g vs 1.5801 ±0.2821 g, P 〈 0.001） was sig- nificantly lower than that in the control group; GC/5- FU treatment can significantly lower the tumor weight （0.4361± 0.1153 g vs 0.7932±0.1283 g, P 〈 0.001）, and the longest median survival time was seen in the GC/5-FU group, compared with the control （12 d vs 30 d, P 〈 0.001）, GC （13 d vs 30 d, P 〈 0.001） and 5-FU groups （17 d vs 30 d, P 〈 0.001）. Flow cytom- etry revealed that compared with the control, GC/5- FU caused a higher rate of G0-G1 arrest （52.79% ± 13.42% vs 23.92%±9.09%, P = 0.014 ） and apopto- sis （2.55% ±1.10% vs 11.13% ±11.73%, P 〈 0.001） in hepatic cancer cells. Analysis of the apoptosis path- ways showed that GC/5-FU upregulated the expression of p53 at both the protein and the mRNA levels, which in turn lowered the ratio of Bcl-2lBax expression; this led to the release of cytochrome C into the cytosol from the mitochondria and the subsequent activation of caspase-3. Upregulation of caspase-3 expression de- creased the PARP-1 at both the mRNA and the protein levels, which contributed to apoptosis. 5-FU increased the levels of aspartate aminotransferase and alanine aminotransferase, and decreased the numbers of platelet, white blood cell and lymphocyte and cytotoxic activities of CTL and NK cells, however, there were no such side effects in the GC/5-FU group. CONCLUSION： GC/5-FU nanoparticles can significant- ly inhibit the growth of liver cancer in mice via the p53 apoptosis pathway, and relieve the side effects and im- munosuppression of 5-FU.
基金The National Institute of Health Grant GM49056 supported this study
文摘Methyl-galactosides were oxidized at room temperature by galactose oxidase in a one-step reaction and afforded methyl-galactoaldehyde in excellent yield and high purity. The resulting galactoaldehyde as a useful intermediate can be directly used in glycopeptide synthesis.
基金Supported by Valio Ltd and the Finnish Funding Agency of Technology and InnovationThe Foundation for Nutrition Research has financially contributed to Liisa Lehtoranta’s doctoral studies
文摘AIM:To study the effects of live and dead Lactobacillus rhamnosus GG(GG) on rotavirus infection in a neonatal rat model.METHODS:At the age of 2 d,suckling Lewis rat pups were supplemented with either live or dead GG and the treatment was continued daily throughout the experi-ment.At the age of 5 and 6 d the pups received oral rotavirus(RV) SA-11 strain.The pups were sacrificed at the age of 7 or 8 d by decapitation.The gastrointestinal tract was removed and macroscopic observations were done.The consistency of feces in the colon was classified using a four-tier system.RV was detected from the plasma,small intestine,colon and feces by real-time quantitative polymerase chain reaction(PCR).RESULTS:In this neonatal rat model,RV induced a mild-to-moderate diarrhea in all except one pup of the RV-inoculated rats.RV moderately reduced body weight development from day 6 onwards.On day 7,after 2 d of RV infection,live and dead GG groups gained significantly more weight than the RV group without probiotics [36%(P = 0.001) and 28%(P = 0.031),respectively].In addition,when compared with the RV control group,both live and dead GG reduced the weight ratio of colon/animal body weight to the same level as in the healthy control group,with reductions of 22%(P = 0.002) and 28%(P < 0.001),respectively.Diarrhea increased moderately in both GG groups.However,the diarrhea incidence and severity in the GG groups were not statistically significantly different as compared with the RV control group.Moreover,observed diarrhea did not provoke weight loss or death.The RV control group had the largest amount of RV PCR-positive samples among the RV-infected groups,and the live GG group had the smallest amount.Rats receiving live GG had significantly less RV in the colon(P = 0.027) when compared with the RV control group.Live GG was also more effective over dead GG in reducing the quantity of RV from plasma(P = 0.047).CONCLUSION:Both live and dead GG have beneficial effects in RV infection.GG may increase RV clearance from the body and reduce colon swelling.
文摘The apple rootstock, A106 (Malus sieboldii), had 17 bivalents in pollen mother cells at meiotic metaphase 1,and 17 chromosomes in a haploid pollen cell. Karyotypes were prepared from root-tip cells with 2n= 34 chromosomes. Seven out of 82 karyotypes (8.5%) showed one pair of satellites at the end of the short arm of chromosome 3. C-bands were shown on 6 pairs of chromosomes 2, 4,6, 8, 14, and 16 near the telomeric regions of short arms.Probes for three ripening-related genes from Malus x domestica: endopolygalacturonase (EPG,0. 6 kb ) , ACC oxidase (1.2 kb), and ACC synthase (2 kb) were hybridized in situ to metaphase chromosomes of A106. Hybridization sites for the EPG gene were observed on the long arm of chromosome 14 in 15 out of 16 replicate spreads and proximal to the centromere of chromosomes 6 and 11. For the ACC oxidase gene, hybridization sites were observed in the telomeric region of the short arm of chromosomes 5 and 11 in 87% and 81% of 16 spreads respectively proximal to the centromere of chromosome 1 in 81% of the spreads, and on the long arm of chromosome 13 in 50% of the spreads. Twenty five spreads were studied for the ACC synthase gene and hybridization sites were observed in the telomeric region of the short arm of chromosome 12 in 96% of the spreads, chromosomes 9 and 10 in 76% of the spreads, and chromosome 17 in 56% of the spreads.
文摘Nucleoside phosphorylase is an important enzyme involved in the biosynthesis of nucleosides. In this study, purine nucleoside phosphorylase and pyrimidine nucleoside phosphorylase were co-expressed in Escherichia coli and the intact cells were used as a catalyst for the biosynthesis of nucleosides. For protein induction, lactose was used in place of isopropyl β-D-l-thiogalactopyranoside （IPTG）. When the concentration of lactose was above 0.5 mmol/L, the ability to induce protein expression was similar to that of IPTG. We determined that the reaction conditions of four bacterial strains co-expressing these genes （TUD, TAD, DUD, and DAD） were similar for the biosyntheses of 2,6-diaminopurine nucleoside and 2,6-diaminopurine deoxynucleoside. When the substrate concentration was 30 mmol/L and 0.5% of the recombinant bacterial cell volume was used as the catalyst （pH 7.5）, a greater than 90% conversion yield was reached after a 2-h incubation at 50℃. In addition, several other nucleosides and nucleoside derivatives were efficiently synthesized using bacterial strains co-expressing these recombinant enzymes.
