This paper aims to provide better guidance for construction of trehalose-producing recombinant strains to further improve the yield of trehalose. The research progress on trehalose biosynthesis pathways and the applic...This paper aims to provide better guidance for construction of trehalose-producing recombinant strains to further improve the yield of trehalose. The research progress on trehalose biosynthesis pathways and the application of molecular biology technique in trehalose study in recent 30 years, especially the last 10 years are reviewed. Results show that there are 5 pathways of trehalose synthesis. Although enzymes and genes of trehalose synthesis have been isolated and genetic engineering strains have increased gradually, the improvement of trehalose yield is still inadequate because most recombinant strains are limited to study the physicochemical properties of single enzyme. With the development of modern biological technology, especially the rapid development of DNA recombinant technology, metagenomics and synthetic biology, high expression of heterologous trehalose in recombinant strains would become a hot research topic in the future.展开更多
High temperature is one of the major abiotic stresses that limit edible mushroom growth and development. The understanding of physiological alterations in response to heat stress and the corresponding mechanisms invol...High temperature is one of the major abiotic stresses that limit edible mushroom growth and development. The understanding of physiological alterations in response to heat stress and the corresponding mechanisms involved is vital for the breeding of heat-resistant edible mushroom strains. Although trehalose functions as a protectant against abiotic stresses in fungi, the putative role of trehalose in thermotolerance remains to be elucidated. In this study, we found heat stress inhibited the growth of two Pleurotus pulmonarius strains, heat-sensitive and less-sensitive, and the inhibition was more significant for the sensitive strain. Heat stress leads to the increase of lipid peroxidation and intracellular trehalose accumulation, with a higher level in the heat-sensitive strain, and this effect is independent of exogenous trehalose application. In addition, a lower concentration of exogenous trehalose application in sensitive strain than in less-sensitive strain was found to alleviate the inhibition of mycelium growth and further increase the intracellular trehalose concentration by heat stress. Thus, the protective effects of trehalose were more remarkable in the sensitive strain. The activities of intracellular trehalose metabolic enzymes, i.e., trehalose-6-phosphate synthase, trehalose phosphorylase and neutral trehalase, were determined, and our data indicated that the changes of these enzymes activities in the sensitive strain were more beneficial to accumulate trehalose than that in the less-sensitive strain.展开更多
Salt stress a ects the growth and development of plants, which results in a decrease in crop quality and yield. In this study, we used tomato seedlings treated with salt and trehalose as experimental materials and ana...Salt stress a ects the growth and development of plants, which results in a decrease in crop quality and yield. In this study, we used tomato seedlings treated with salt and trehalose as experimental materials and analyzed them using the technique for order preference by similarity to ideal solution analysis to select the optimal trehalose concentration for treatment. We also determined the contents of sugar and abscisic acid (ABA) and detected the expression of genes involved in the metabolism of sugar and ABA by quantitative real-time PCR. Results showed that the optimal trehalose concentration was 2 mmol/L for tomato seedlings under salt stress. Exogenous trehalose decreased the starch content and increased the soluble sugar con- tent by a ecting the expression of genes related to the metabolism of starch and soluble sugar. Exogenous trehalose altered the accumulation and distribution of sugar by inducing the upregulation of sugar transporter genes. Furthermore, trehalose increased the ABA content to induce salt stress response by regulating the expression of genes related to the synthesis and metabolism of ABA. In conclusion, trehalose can e ectively alleviate salt stress and enhance salt tolerance of tomato. These ndings provide a novel perspective and a better resource to investigate the salt tolerance mechanism and a new method for alleviating salt stress in tomato.展开更多
Most aspects of microspore culture protocol have the capacity to cause stress to microspores, hence, less stressful treatments might be required to avoid deleterious effects. In stressed plants, polyamines and trehalo...Most aspects of microspore culture protocol have the capacity to cause stress to microspores, hence, less stressful treatments might be required to avoid deleterious effects. In stressed plants, polyamines and trehalose can act as compatible solutes or osmoprotectants by stabilizing proteins and biological membranes. To improve green plant regeneration in wheat microspore culture, this study assessed the effects of polyamines (putrecine, spermidine, spermine) and trehalose on androgenic response namely embryogenesis, green plant regeneration and ploidy of green plants regenerated in three spring wheat genotypes. Microspores of the genotypes produced significant numbers of embryos and green plants among polyamine treatments but trehalose had no effect (P ≤ 0.05). Polyamine treatments for 30 min generally produced more green plants per 100 microspores than the 60 min treatments in all three genotypes. At least three out of twelve polyamine treatments in each genotype improved the production of double haploid plants and seed setting in regenerants. Wheat genotype, concentration and duration of polyamine treatment had significant impact on embryogenesis and regeneration of green plants in this study. The study also showed that polyamines could be used to accelerate cultivar development in wheat breeding.展开更多
Lactic acid bacteria （LAB） were encapsulated with alginate, gelatin and trehalose additives by the extrusion method and dried at 4 ℃. The microcapsules were generally spherical and had a wrinkled surface with a siz...Lactic acid bacteria （LAB） were encapsulated with alginate, gelatin and trehalose additives by the extrusion method and dried at 4 ℃. The microcapsules were generally spherical and had a wrinkled surface with a size of 1.7mm± 0.2mm Trehalose as a carbohydrate source in the culture medium could reduce acid production and performed no function in the positive proliferation of LAB. Using trehalose as a carbohydrate source and protective medittm simultaneously had a benefit in the protection of LAB cells during the storage at 4 ℃. The density of live LAB cells could be 10^7 CFU g^-1 after 8weeks of storage. Cells of LAB could be continuously released from the capsules from the acidic （pH 1.2） to neutral conditions （pH 6.8）. The release amounts and proliferation speeds of LAB cells in neutral medium were much larger and faster than those in acidic conditions. Additionally, nxtmobilization of LAB could improve the survival of cells when they were exposed to acidic medium （pH 1.2） with a survival rate of 76%.展开更多
Trehalose synthase gene (TSase) from Grifola frondosa was transferred into sugarcane (Sac-charum hybrid L.) using Agrobacterium-mediated method to improve sugarcane drought-tolerance. The results indicated that embryo...Trehalose synthase gene (TSase) from Grifola frondosa was transferred into sugarcane (Sac-charum hybrid L.) using Agrobacterium-mediated method to improve sugarcane drought-tolerance. The results indicated that embryogenic callus of sugarcane was sensitive to A. tumefaciens EHA105 strain in the transformation system employed. The high frequency PPT-resistant plants were obtained from transformated with 3 weeks callus after incubation, which reached 4.5% on average. The transgenic plants were confirmed by PCR and Southern analysis. Some transgenic plants showed multiple phenotypic alterations and some plants demonstrated improvement tolerance to osmotic stress.展开更多
Trehalose can be determined by thin layer chromatography and high performance liquid chromatography. But it's difficult to distinguish trehalose from the similar bisaccharides. If the reaction of the reduced bisac...Trehalose can be determined by thin layer chromatography and high performance liquid chromatography. But it's difficult to distinguish trehalose from the similar bisaccharides. If the reaction of the reduced bisaccharides with phenyl hydrazine to form osazone is used, then the disturbance of the similar reduced bisaccharides can be rapidly and conveniently excluded, or via the ammoniated-reduced reaction, aliline can be specially bounded to the reduced hydroxyl of the bisaccharides. In that way trehalose can be accurately determined.展开更多
Trehalose is a non-reducing disaccharide composed of glucose molecules connected byα-glycosidic bond.This soluble substance plays an important role of protecting green algae and other lower plants from stress.It can ...Trehalose is a non-reducing disaccharide composed of glucose molecules connected byα-glycosidic bond.This soluble substance plays an important role of protecting green algae and other lower plants from stress.It can help plants cope with extreme environments such as severe cold,drought and high salinity,regulate the stomatal conductance and water utilization rate of plants,and participate in the growth and metabolism regulation of plants as a signal molecule.As an impermeable cryoprotectant,trehalose is widely used in the refrigeration protection of various animal cells and tissues due to its non-toxicity and high efficiency.According to the research results at home and abroad in recent years,the protection,regulation and mechanism of trehalose on plant tissues and animal cells were summarized,so as to provide a theoretical basis for the further development and utilization of trehalose.展开更多
Bacillus subtilis is a non-pathogenic Gram-positive bacterium that has been widely used to produce industrially and pharmaceutically relevant proteins. Trehalose, a non reducing disaccharide used as protective agent a...Bacillus subtilis is a non-pathogenic Gram-positive bacterium that has been widely used to produce industrially and pharmaceutically relevant proteins. Trehalose, a non reducing disaccharide used as protective agent and additive in foodstuffs and pharmaceutical products, can be prepared by trehalose synthase(TreS). The present work aims to construct a robust recombinant B. subtilis to achieve the secretory expression of TreS. In this study, the treS gene from Pseudomonas putida ATCC47054 was amplified by PCR and further cloned and expressed in B. subtilis WB800 N using pHT01 as expression vector. For avoiding the use of inducer, promoter P_(srfA) was used to replace the promoter P_(grac) in pHT01 and verify the activity of recombinant trehalose synthase. The TreS activity assay was employed to evaluate the performance of recombinant B. subtilis W800 N under different phosphate concentrations, carbon sources, carbon source concentrations, nitrogen sources and pH. The results showed that the P_(srfA) promoter had a good regulation effect under pH 8.0 condition, and the enzyme activity reached 6 000 U/L. Using the PhoD as the secretory signal peptide, TreS was effectively secreted, and the extracellular enzyme activity reached 2 100 U/L, accounting for 35% of the total enzyme activity. By optimizing the medium and fermentation conditions, the extracellular enzyme activity reached 6 900 U/L in 5 L of fermentor, and the proportion reached 48%. The pHT01-P_(srfA)-PhoD-treS secretory recombinant B. subtilis constructed in this study has great potential in trehalose synthase production.展开更多
Limited information exists about the effects of antioxidants on sperm motility and DNA integrity during vitrification in humans. This study compared the effects of reduced glutathione (GSH) and monothioglycerol (MTG) ...Limited information exists about the effects of antioxidants on sperm motility and DNA integrity during vitrification in humans. This study compared the effects of reduced glutathione (GSH) and monothioglycerol (MTG) at different concentrations on post-thaw sperm motility and DNA integrity after vitrification in humans using 0.25 M trehalose as a cryoprotective agent, and found that supplementation of MTG or GSH at 0.5 mM resulted in significantly higher (P < 0.05) recovery rates of post-thaw total and progressive motilities. GSH was more powerful than MTG at the same concentration in cryoprotecting sperm motility (38.9% ± 3.6% vs 32.8% ± 2.4% compared to the control 26.8% ± 2.1% in recovery rate of progressive motility), but both had no significant influence on sperm DNA integrity during vitrification. It was concluded that sperm motility is more sensitive to oxidative stress during vitrification than sperm nuclear DNA, and supplementation of MTG or GSH in vitrification medium is beneficial in cryoprotecting sperm motility.展开更多
In recent years, sugar-derived polymer materials have been actively investigated. In research of polyurethane (PU), sugar has been used as a raw material because it has properties similar to polyol. However, the elast...In recent years, sugar-derived polymer materials have been actively investigated. In research of polyurethane (PU), sugar has been used as a raw material because it has properties similar to polyol. However, the elastic property of the obtained PU is substantially lost. Hence, the introduction of a sugar unit to PU while maintaining the elastic property remains a challenge in polymer chemistry. Here, we report the synthesis of a polyurethane elastomer (PUE) with a trehalose unit using raw materials such as an aromatic diisocyanate (4,4’-diphenylmethane diisocyanate), polyols including a polyether polyol (polytetramethylene glycol), two polyester polyols (polycaprolactone and polycarbonate diol), and trehalose. Novel PUEs with trehalose units are synthesized by a one-shot method. Trehalose, which has non-reducing properties, is used as sugar. The use of trehalose, which has been scarcely applied to PUE, is essential to obtain the desired PUEs with sugar units.展开更多
Photorhabdus luminescens is a Gram-negative, bioluminescent, pigment producing enteric bacterium, which is pathogenic to insects and has the capability to undergo phase variation. The phase I variant of P. luminescens...Photorhabdus luminescens is a Gram-negative, bioluminescent, pigment producing enteric bacterium, which is pathogenic to insects and has the capability to undergo phase variation. The phase I variant of P. luminescens exists as a mutualistic symbiont where it plays a critical role in the life-cycle of the soil-dwelling nematode, Heterorhabditis bacteriophora. Both the bacterium and the nematode receive their nutritional requirements from the bioconversion of the insect host which is rich in many macromolecules such as the disaccharide, trehalose. Trehalose is a non-reducing disaccharide of glucose that is formed by an a-1,1-glycosidic bond and is associated with the physiology of many bacteria, insects and nematodes. Trehalose has been shown to be the most abundant storage sugar found within insect hemolymph （1%-2%）. The physicochemical properties of trehalose allow this carbohydrate to act as a stress protectant where it has been implicated with thermal stress, dehydration, and osmotic protection of many microorganisms. Due to these properties, trehalose may allow culture stability of the phase I variant in vitro and in vivo. Traits of the phase I variant that were studied in this work include bioluminescence and the production of the red anthroquinone-derived pigment. The carbohydrates that were utilized in this study were glucose and trehalose; where shake flask cultures of the phase I variant were cultured at room temperature for up to six days in carbohydrate supplemented basal media with increasing carbohydrate concentrations of 0. 1%, 0.5% and 1.0% （v/v）. Relative luminosity, pigmentation and pH were graphed as a function of time, carbohydrate used, and carbohydrate concentration. Data obtained from this study suggests that the supplementation of 1.0% trehalose, when culturing the phase I variant ofP. luminescens, can maintain bioluminosity and pigmentation over extended periods of time （five days） as compared to basal media and basal media supplemented with 1.0% glucose.展开更多
[ Objective] This study aimed to explore the immobitizatian of trehalose synthase on mesoporous molecular sieves. [ Method] With trehalose synthase produced by genetically engineered bacteria as experimental material,...[ Objective] This study aimed to explore the immobitizatian of trehalose synthase on mesoporous molecular sieves. [ Method] With trehalose synthase produced by genetically engineered bacteria as experimental material, rnesoporous molecular sieve MCM-41 was used as a carrier for immobilization of trehalase syn- thase. Properties of trehalose synthase before and after immobilization were compared. [ Result ] Trehalose synthase could be immohihzed on mesoporous molecular sieve MCM-41 by using physical adsorption method. Immobilization of trehalose synthase achieved the best effect at pH 3.0, with enzyme amount of 62.5 mg/g and immobilization duration of 12 h. Compared with the free u, ehalose synthase, immobilized trehalose synthase showed significantly improved pH stability and thermal stability with repeatable operation, which was conducive to the utilization and storage of enzyme. [ Conclusion] This study provided theoretical basis for the devel- opment of new immobilized trehalose synthase.展开更多
Rapid freezing and vitrification are becoming popular for human sperm cryopreservation;however, it remains unclear which method is better. The aims of the present study were to determine the optimal trehalose concentr...Rapid freezing and vitrification are becoming popular for human sperm cryopreservation;however, it remains unclear which method is better. The aims of the present study were to determine the optimal trehalose concentration and to compare the cryoprotective effects of rapid freezing and vitrification. The results showed that: 1) The optimal trehalose concentration was 0.25 mol/L;2) The post-thaw recovery rates of total and progressive sperm motilities after rapid freezing (38.6% ± 3.0% and 41.1% ± 5.0%) were significantly higher (P 0.05) than that after vitrification (26.1% ± 3.1% and 27.2% ± 1.3%) when 0.5 mL straws were used;3) However, the recovery rates of total and progressive motilities after rapid freezing in 0.5 mL straw (26.7% ± 9.6% and 26.8% ± 8.7%) were significantly lower (P 0.05) than that after vitrification in a novel straw-in-straw system (43.1% ± 4.2% and 41.8% ± 15.5%);and 4) The post-thaw sperm nuclear DNA damage level after rapid freezing in 0.5 mL straw (8.7% ± 2.8%) was not significantly different from that of sperm after vitrification in the straw-in-straw system (9.2% ± 2.5%). It was concluded that rapid freezing is superior to vitrification when using 0.5 mL straws;however, vitrification is superior to rapid freezing when using the straw-in-straw systems.展开更多
文摘This paper aims to provide better guidance for construction of trehalose-producing recombinant strains to further improve the yield of trehalose. The research progress on trehalose biosynthesis pathways and the application of molecular biology technique in trehalose study in recent 30 years, especially the last 10 years are reviewed. Results show that there are 5 pathways of trehalose synthesis. Although enzymes and genes of trehalose synthesis have been isolated and genetic engineering strains have increased gradually, the improvement of trehalose yield is still inadequate because most recombinant strains are limited to study the physicochemical properties of single enzyme. With the development of modern biological technology, especially the rapid development of DNA recombinant technology, metagenomics and synthetic biology, high expression of heterologous trehalose in recombinant strains would become a hot research topic in the future.
基金supported by the National Basic Research Program of China (2014CB138303)the earmarked fund for China Agriculture Research System (CARS20)
文摘High temperature is one of the major abiotic stresses that limit edible mushroom growth and development. The understanding of physiological alterations in response to heat stress and the corresponding mechanisms involved is vital for the breeding of heat-resistant edible mushroom strains. Although trehalose functions as a protectant against abiotic stresses in fungi, the putative role of trehalose in thermotolerance remains to be elucidated. In this study, we found heat stress inhibited the growth of two Pleurotus pulmonarius strains, heat-sensitive and less-sensitive, and the inhibition was more significant for the sensitive strain. Heat stress leads to the increase of lipid peroxidation and intracellular trehalose accumulation, with a higher level in the heat-sensitive strain, and this effect is independent of exogenous trehalose application. In addition, a lower concentration of exogenous trehalose application in sensitive strain than in less-sensitive strain was found to alleviate the inhibition of mycelium growth and further increase the intracellular trehalose concentration by heat stress. Thus, the protective effects of trehalose were more remarkable in the sensitive strain. The activities of intracellular trehalose metabolic enzymes, i.e., trehalose-6-phosphate synthase, trehalose phosphorylase and neutral trehalase, were determined, and our data indicated that the changes of these enzymes activities in the sensitive strain were more beneficial to accumulate trehalose than that in the less-sensitive strain.
基金supported by the National Natural Science Foundation of China (Nos. 31671899 and 31871848)
文摘Salt stress a ects the growth and development of plants, which results in a decrease in crop quality and yield. In this study, we used tomato seedlings treated with salt and trehalose as experimental materials and analyzed them using the technique for order preference by similarity to ideal solution analysis to select the optimal trehalose concentration for treatment. We also determined the contents of sugar and abscisic acid (ABA) and detected the expression of genes involved in the metabolism of sugar and ABA by quantitative real-time PCR. Results showed that the optimal trehalose concentration was 2 mmol/L for tomato seedlings under salt stress. Exogenous trehalose decreased the starch content and increased the soluble sugar con- tent by a ecting the expression of genes related to the metabolism of starch and soluble sugar. Exogenous trehalose altered the accumulation and distribution of sugar by inducing the upregulation of sugar transporter genes. Furthermore, trehalose increased the ABA content to induce salt stress response by regulating the expression of genes related to the synthesis and metabolism of ABA. In conclusion, trehalose can e ectively alleviate salt stress and enhance salt tolerance of tomato. These ndings provide a novel perspective and a better resource to investigate the salt tolerance mechanism and a new method for alleviating salt stress in tomato.
文摘Most aspects of microspore culture protocol have the capacity to cause stress to microspores, hence, less stressful treatments might be required to avoid deleterious effects. In stressed plants, polyamines and trehalose can act as compatible solutes or osmoprotectants by stabilizing proteins and biological membranes. To improve green plant regeneration in wheat microspore culture, this study assessed the effects of polyamines (putrecine, spermidine, spermine) and trehalose on androgenic response namely embryogenesis, green plant regeneration and ploidy of green plants regenerated in three spring wheat genotypes. Microspores of the genotypes produced significant numbers of embryos and green plants among polyamine treatments but trehalose had no effect (P ≤ 0.05). Polyamine treatments for 30 min generally produced more green plants per 100 microspores than the 60 min treatments in all three genotypes. At least three out of twelve polyamine treatments in each genotype improved the production of double haploid plants and seed setting in regenerants. Wheat genotype, concentration and duration of polyamine treatment had significant impact on embryogenesis and regeneration of green plants in this study. The study also showed that polyamines could be used to accelerate cultivar development in wheat breeding.
基金the financial support from NSFC (30670566)the ISTCP (2006DFA 33150).
文摘Lactic acid bacteria （LAB） were encapsulated with alginate, gelatin and trehalose additives by the extrusion method and dried at 4 ℃. The microcapsules were generally spherical and had a wrinkled surface with a size of 1.7mm± 0.2mm Trehalose as a carbohydrate source in the culture medium could reduce acid production and performed no function in the positive proliferation of LAB. Using trehalose as a carbohydrate source and protective medittm simultaneously had a benefit in the protection of LAB cells during the storage at 4 ℃. The density of live LAB cells could be 10^7 CFU g^-1 after 8weeks of storage. Cells of LAB could be continuously released from the capsules from the acidic （pH 1.2） to neutral conditions （pH 6.8）. The release amounts and proliferation speeds of LAB cells in neutral medium were much larger and faster than those in acidic conditions. Additionally, nxtmobilization of LAB could improve the survival of cells when they were exposed to acidic medium （pH 1.2） with a survival rate of 76%.
基金This work was supported by the National Natural Science Foundation of China(30160045).
文摘Trehalose synthase gene (TSase) from Grifola frondosa was transferred into sugarcane (Sac-charum hybrid L.) using Agrobacterium-mediated method to improve sugarcane drought-tolerance. The results indicated that embryogenic callus of sugarcane was sensitive to A. tumefaciens EHA105 strain in the transformation system employed. The high frequency PPT-resistant plants were obtained from transformated with 3 weeks callus after incubation, which reached 4.5% on average. The transgenic plants were confirmed by PCR and Southern analysis. Some transgenic plants showed multiple phenotypic alterations and some plants demonstrated improvement tolerance to osmotic stress.
基金the National Natural Science Foundation of China
文摘Trehalose can be determined by thin layer chromatography and high performance liquid chromatography. But it's difficult to distinguish trehalose from the similar bisaccharides. If the reaction of the reduced bisaccharides with phenyl hydrazine to form osazone is used, then the disturbance of the similar reduced bisaccharides can be rapidly and conveniently excluded, or via the ammoniated-reduced reaction, aliline can be specially bounded to the reduced hydroxyl of the bisaccharides. In that way trehalose can be accurately determined.
基金Supported by Henan Provincial Key Project(154200510025,182102210354,182102310665,18ZP05001)
文摘Trehalose is a non-reducing disaccharide composed of glucose molecules connected byα-glycosidic bond.This soluble substance plays an important role of protecting green algae and other lower plants from stress.It can help plants cope with extreme environments such as severe cold,drought and high salinity,regulate the stomatal conductance and water utilization rate of plants,and participate in the growth and metabolism regulation of plants as a signal molecule.As an impermeable cryoprotectant,trehalose is widely used in the refrigeration protection of various animal cells and tissues due to its non-toxicity and high efficiency.According to the research results at home and abroad in recent years,the protection,regulation and mechanism of trehalose on plant tissues and animal cells were summarized,so as to provide a theoretical basis for the further development and utilization of trehalose.
基金Supported by the National Nature Science Foundation of China(No.31501413)Shandong key project of Research&Development plan(No.2017GSF221019)+1 种基金Young doctorate Cooperation Fund Project,Qi Lu University of Technology(Shandong Academy of Sciences)(No.2017BSHZ021)Shandong Natural Science Foundation Project(ZR2017BC072)
文摘Bacillus subtilis is a non-pathogenic Gram-positive bacterium that has been widely used to produce industrially and pharmaceutically relevant proteins. Trehalose, a non reducing disaccharide used as protective agent and additive in foodstuffs and pharmaceutical products, can be prepared by trehalose synthase(TreS). The present work aims to construct a robust recombinant B. subtilis to achieve the secretory expression of TreS. In this study, the treS gene from Pseudomonas putida ATCC47054 was amplified by PCR and further cloned and expressed in B. subtilis WB800 N using pHT01 as expression vector. For avoiding the use of inducer, promoter P_(srfA) was used to replace the promoter P_(grac) in pHT01 and verify the activity of recombinant trehalose synthase. The TreS activity assay was employed to evaluate the performance of recombinant B. subtilis W800 N under different phosphate concentrations, carbon sources, carbon source concentrations, nitrogen sources and pH. The results showed that the P_(srfA) promoter had a good regulation effect under pH 8.0 condition, and the enzyme activity reached 6 000 U/L. Using the PhoD as the secretory signal peptide, TreS was effectively secreted, and the extracellular enzyme activity reached 2 100 U/L, accounting for 35% of the total enzyme activity. By optimizing the medium and fermentation conditions, the extracellular enzyme activity reached 6 900 U/L in 5 L of fermentor, and the proportion reached 48%. The pHT01-P_(srfA)-PhoD-treS secretory recombinant B. subtilis constructed in this study has great potential in trehalose synthase production.
文摘Limited information exists about the effects of antioxidants on sperm motility and DNA integrity during vitrification in humans. This study compared the effects of reduced glutathione (GSH) and monothioglycerol (MTG) at different concentrations on post-thaw sperm motility and DNA integrity after vitrification in humans using 0.25 M trehalose as a cryoprotective agent, and found that supplementation of MTG or GSH at 0.5 mM resulted in significantly higher (P < 0.05) recovery rates of post-thaw total and progressive motilities. GSH was more powerful than MTG at the same concentration in cryoprotecting sperm motility (38.9% ± 3.6% vs 32.8% ± 2.4% compared to the control 26.8% ± 2.1% in recovery rate of progressive motility), but both had no significant influence on sperm DNA integrity during vitrification. It was concluded that sperm motility is more sensitive to oxidative stress during vitrification than sperm nuclear DNA, and supplementation of MTG or GSH in vitrification medium is beneficial in cryoprotecting sperm motility.
文摘In recent years, sugar-derived polymer materials have been actively investigated. In research of polyurethane (PU), sugar has been used as a raw material because it has properties similar to polyol. However, the elastic property of the obtained PU is substantially lost. Hence, the introduction of a sugar unit to PU while maintaining the elastic property remains a challenge in polymer chemistry. Here, we report the synthesis of a polyurethane elastomer (PUE) with a trehalose unit using raw materials such as an aromatic diisocyanate (4,4’-diphenylmethane diisocyanate), polyols including a polyether polyol (polytetramethylene glycol), two polyester polyols (polycaprolactone and polycarbonate diol), and trehalose. Novel PUEs with trehalose units are synthesized by a one-shot method. Trehalose, which has non-reducing properties, is used as sugar. The use of trehalose, which has been scarcely applied to PUE, is essential to obtain the desired PUEs with sugar units.
文摘Photorhabdus luminescens is a Gram-negative, bioluminescent, pigment producing enteric bacterium, which is pathogenic to insects and has the capability to undergo phase variation. The phase I variant of P. luminescens exists as a mutualistic symbiont where it plays a critical role in the life-cycle of the soil-dwelling nematode, Heterorhabditis bacteriophora. Both the bacterium and the nematode receive their nutritional requirements from the bioconversion of the insect host which is rich in many macromolecules such as the disaccharide, trehalose. Trehalose is a non-reducing disaccharide of glucose that is formed by an a-1,1-glycosidic bond and is associated with the physiology of many bacteria, insects and nematodes. Trehalose has been shown to be the most abundant storage sugar found within insect hemolymph （1%-2%）. The physicochemical properties of trehalose allow this carbohydrate to act as a stress protectant where it has been implicated with thermal stress, dehydration, and osmotic protection of many microorganisms. Due to these properties, trehalose may allow culture stability of the phase I variant in vitro and in vivo. Traits of the phase I variant that were studied in this work include bioluminescence and the production of the red anthroquinone-derived pigment. The carbohydrates that were utilized in this study were glucose and trehalose; where shake flask cultures of the phase I variant were cultured at room temperature for up to six days in carbohydrate supplemented basal media with increasing carbohydrate concentrations of 0. 1%, 0.5% and 1.0% （v/v）. Relative luminosity, pigmentation and pH were graphed as a function of time, carbohydrate used, and carbohydrate concentration. Data obtained from this study suggests that the supplementation of 1.0% trehalose, when culturing the phase I variant ofP. luminescens, can maintain bioluminosity and pigmentation over extended periods of time （five days） as compared to basal media and basal media supplemented with 1.0% glucose.
基金Supported by Fund of Liaoning Provincial Department of Education ( L2010335)
文摘[ Objective] This study aimed to explore the immobitizatian of trehalose synthase on mesoporous molecular sieves. [ Method] With trehalose synthase produced by genetically engineered bacteria as experimental material, rnesoporous molecular sieve MCM-41 was used as a carrier for immobilization of trehalase syn- thase. Properties of trehalose synthase before and after immobilization were compared. [ Result ] Trehalose synthase could be immohihzed on mesoporous molecular sieve MCM-41 by using physical adsorption method. Immobilization of trehalose synthase achieved the best effect at pH 3.0, with enzyme amount of 62.5 mg/g and immobilization duration of 12 h. Compared with the free u, ehalose synthase, immobilized trehalose synthase showed significantly improved pH stability and thermal stability with repeatable operation, which was conducive to the utilization and storage of enzyme. [ Conclusion] This study provided theoretical basis for the devel- opment of new immobilized trehalose synthase.
文摘Rapid freezing and vitrification are becoming popular for human sperm cryopreservation;however, it remains unclear which method is better. The aims of the present study were to determine the optimal trehalose concentration and to compare the cryoprotective effects of rapid freezing and vitrification. The results showed that: 1) The optimal trehalose concentration was 0.25 mol/L;2) The post-thaw recovery rates of total and progressive sperm motilities after rapid freezing (38.6% ± 3.0% and 41.1% ± 5.0%) were significantly higher (P 0.05) than that after vitrification (26.1% ± 3.1% and 27.2% ± 1.3%) when 0.5 mL straws were used;3) However, the recovery rates of total and progressive motilities after rapid freezing in 0.5 mL straw (26.7% ± 9.6% and 26.8% ± 8.7%) were significantly lower (P 0.05) than that after vitrification in a novel straw-in-straw system (43.1% ± 4.2% and 41.8% ± 15.5%);and 4) The post-thaw sperm nuclear DNA damage level after rapid freezing in 0.5 mL straw (8.7% ± 2.8%) was not significantly different from that of sperm after vitrification in the straw-in-straw system (9.2% ± 2.5%). It was concluded that rapid freezing is superior to vitrification when using 0.5 mL straws;however, vitrification is superior to rapid freezing when using the straw-in-straw systems.
