The xylitol dehydrogenase(XDH)is a crucial enzyme involved in the xylose utilization in pentose⁃catabolizing yeasts and fungi.In addition to producing xylulose,XDH can also be employed to develop a biosensor for monit...The xylitol dehydrogenase(XDH)is a crucial enzyme involved in the xylose utilization in pentose⁃catabolizing yeasts and fungi.In addition to producing xylulose,XDH can also be employed to develop a biosensor for monitoring xylitol concentration.In this study,the gene encoding the thermophilic fungus Talaromyces emersonii XDH(TeXDH)was heterologously expressed in Escherichia coli BL21(DE3)at 16℃in the soluble form.Recombinant TeXDH with high purity was purified by using a Ni⁃NTA affinity column.Size⁃exclusion chromatography and SDS⁃PAGE analysis demonstrated that the puri⁃fied recombinant TeXDH exists as a native trimer with a molecular mass of approximately 116 kD,and is composed of three identical subunits,each with a molecular weight of around 39 kD.The TeXDH strictly preferred NAD^(+)as a coenzyme to NADP^(+).The optimal temperature and pH of the TeXDH were 40℃and 10.0,respectively.After EDTA treatment,the enzyme activity of TeXDH decreased to 43.26%of the initial enzyme activity,while the divalent metal ions Mg^(2+)or Ca^(2+)could recover the enzyme activity of TeXDH,reaching 103.32%and 110.69%of the initial enzyme activity,respectively,making them the optimal divalent metal ion cofactors for TeXDH enzyme.However,the divalent metal ions of Mn^(2+),Ni^(2+),Cu^(2+),Zn^(2+),Co^(2+),and Cd^(2+)significantly inhibited the activity of TeXDH.ICP⁃MS and molecular doc⁃king studies revealed that 1 mol/L of TeXDH bound 2 mol/L Zn^(2+)ions and 1 mol/L Mg^(2+)ion.Further⁃more,TeXDH exhibited a high specificity for xylitol,laying the foundation for the development of future xylitol biosensors.展开更多
Traditional biodiesel production primarily uses methanol as the acyl acceptor,but its toxicity to lipase increases process complexity and operational difficulty elevate manufacturing costs.This study aimed to explore ...Traditional biodiesel production primarily uses methanol as the acyl acceptor,but its toxicity to lipase increases process complexity and operational difficulty elevate manufacturing costs.This study aimed to explore a new method for enzymatic synthesis of biodiesel with methyl methacrylate(MMA)as acyl acceptor.Meanwhile,a 1,3-position specific lipase Lipozyme RM IM was applied as biocatalyst,which enables simultaneous production of biodiesel(FAMEs)and methacrylate fatty acid glycerides(MFAGs)via specific sn-1,3 transesterification of MMA with triglyceride.Under the optimal reaction conditions:temperature of 50℃,molar ratio of 4:1 for MMA to triglyceride,enzyme dosage of 7.5%(mass),and an extra water addition of 0.5%(mass);triglyceride conversion rate of 97%,and FAMEs yield of 65%could be obtained.Simultaneously,the multistage short-path distillation and column chromatographic method were combined used for the separation of the mixed products.Finally,the purity of FAME,MFADG,DMFAG,and MMFAG were 98%,97.8%,95.3%,and 81.78%,respectively.In this new approach,MMA demonstrates lower toxicity to lipases,allowing for straightfo rward addition of all the substrates without complex addition process,and enhancing operational feasibility.Meanwhile,the by-products of MFAGs could be applied as monomers in varnishes and protective coatings,which increased the value of the products.Thus,this investigation providing an alternative way to produce biodiesel,and providing a new pathway for the sustainable development of biodiesel.展开更多
This editorial critically analyses the recent article by Jung et al,which investigates the utility of 4-hour serum amylase and lipase as early blood markers for postendoscopic retrograde cholangiopancreatography(ERCP)...This editorial critically analyses the recent article by Jung et al,which investigates the utility of 4-hour serum amylase and lipase as early blood markers for postendoscopic retrograde cholangiopancreatography(ERCP)acute pancreatitis prediction.Although these enzymes are valuable for the early diagnosis of post-ERCP pancreatitis,they lack specificity for disease etiology and provide limited insight into the molecular mechanisms underlying disease progression.Several cytokines,notably interleukin(IL)-6,tumor necrosis factor-alpha,and IL-8,are increased in post-ERCP pancreatitis and may serve as potential predictors for disease severity.The incorporation of these biomarkers in early enzymatic biomarkers and established prognostic scoring systems could further enhance their accuracy and allow for earlier,more effective management of patients with post-ERCP pancreatitis.展开更多
Enzymatic modification is an important approach to changing the structure and expanding industrial application of natural starch. In the process of starch modification, thermostable enzymes are favored owing to their ...Enzymatic modification is an important approach to changing the structure and expanding industrial application of natural starch. In the process of starch modification, thermostable enzymes are favored owing to their compatibility with higher reaction temperatures and lower required dosage. In this study, thermostable glucoamylase from Thermothelomyces thermophilus(TtGA) was heterologously expressed in Pichia pastoris, and its effects on the structure and physicochemical properties of raw corn starch were determined. The purified TtGA had a molecular weight of approximately 66 kDa, and its optimum reaction temperature and pH were 50 ℃ and 5.0, respectively. TtGA retained > 60% of its activity following treatment at 60 ℃ for 2 h and remained stable within a pH range of 4.0–7.0 for 6 h. The enzymatic modification of raw corn starch with TtGA led to 3% hydrolysis at 50 ℃ for 24 h. In comparison with natural raw corn starch, TtGA-modified starch had a smaller particle size with an unchanged crystalline structure, increased relative crystallinity, and amylose content.Scanning electronic observation showed that larger pores were formed on the surface of starch particles, and Fourier-transform infrared spectroscopy indicated that TtGA increased the degree of order in the raw corn starch.TtGA modification caused enhanced viscosity of the raw corn starch and altered the rheological properties with decreases in storage and loss moduli, as well as shear viscosity. Moreover, TtGA treatment enhanced the thermal characteristics of the raw corn starch, and decreased gelatinization enthalpy. This study provides detailed evidence for TtGA modification of raw corn starch, which would be helpful for its practical utilization in starch modification.展开更多
Background In intensive aquaculture systems,the frequent incidence of enteritis reduces production efficiency and results in significant economic losses.Protein feeds account for 40%–60%of aquafeed expenses,and with ...Background In intensive aquaculture systems,the frequent incidence of enteritis reduces production efficiency and results in significant economic losses.Protein feeds account for 40%–60%of aquafeed expenses,and with the growth of intensive aquaculture,demand for fishmeal as a key protein source outstrips supply,driving up prices.This study investigated the therapeutic potential of reducing dietary protein levels by 3%and adding enzymatic cottonseed protein(ECP)in juvenile yellow catfish with dextran sulfate sodium(DSS)-induced enteritis.Methods A total of 1,260 healthy juvenile yellow catfish(Pelteobagrus fulvidraco),with an average body weight of 5.90±0.05 g,were randomly allocated into 7 experimental groups,each with 3 replicates.The fish were fed one of seven diets for 10 weeks:a normal-protein diet(42%;NP)and 6 low-protein diets(39%;LP)supplemented with graded levels of ECP at 0%(ECP0),1%(ECP1),2%(ECP2),3%(ECP3),4%(ECP4),and 5%(ECP5),respectively.Subsequently,48 fish from each group were selected to receive 1 mL of 6%DSS solution.Results Our findings demonstrated that:(1)The DSS+ECP0 group aggravated DSS-induced enteritis in juvenile yellow catfish compared to the DSS+NP group.(2)Dietary supplementation of ECP in LP diets significantly enhanced the enzymatic activity and levels of immunoreactive substances,including LZM,C3,C4,and ACP(P<0.05).Mechanistically,first,ECP supplementation modulated macrophage polarization by inhibiting the M1 phenotype while promoting the M2 phenotype,potentially through the JAK-STAT signaling pathway;second,dietary ECP suppressed the phosphorylation cascade of key necroptosis-related proteins,including RIP1,RIP3,and MLKL,potentially via the NF-κB and MAPK signaling pathways.(3)The DSS+ECP2 group demonstrated comparable or superior efficacy to the DSS+NP group in mitigating DSS-induced intestinal enteritis.Conclusions Our results demonstrated that ECP can alleviate DSS-induced enteritis by regulating macrophage polarization and reducing necroptosis.Furthermore,ECP supplementation effectively counteracted the exacerbation of enteritis caused by dietary protein reduction.These findings highlighted the effectiveness and feasibility of ECP in alleviating enteritis and saving protein.展开更多
Saponins can be potential candidates for the development of safe biopesticides,due to their widely acknowledged insecticidal,fungicidal and nematicidal activity,but information on their effects on soil biological prop...Saponins can be potential candidates for the development of safe biopesticides,due to their widely acknowledged insecticidal,fungicidal and nematicidal activity,but information on their effects on soil biological properties is still limited.This study aimed to investigate the short-term fate of saponins from Medicago sativa in soil and their dose-effect relationship with microbial biomass and selected enzyme activities in soils with different origin,physical and chemical properties.Microbial degradation of total saponins ranged from 46%to 91%,according to soil characteristics,within 28 days from their incorporation into the soil.Both saponin glycosidic chains and triterpenic aglycones were also microbially degraded,though by dynamics changing among the different soils.In all soils,M.sativa saponins significantly reduced microbial biomass at rates of 10 and 20 mg saponin mixture per g of soil.Microbial enzymatic activities were less affected as indicating an adaptive response of soil microbial communities to the presence of saponins.展开更多
Aim An industrial enzyme β-glucanase was used to transfortn notoginsenoside Fe for the first time. Methods Notoginsenoside Fe was isolated from the leave saponin of Panax notoginseng （Burk.） Chen FH. The enzymatica...Aim An industrial enzyme β-glucanase was used to transfortn notoginsenoside Fe for the first time. Methods Notoginsenoside Fe was isolated from the leave saponin of Panax notoginseng （Burk.） Chen FH. The enzymatically transformed compounds were detected by HPLC and two transformed compounds were identified as 20 （S） -protopanaxadiol-20- O- α-L-arabinofuranosyl （ 1→6 ） - β-gluco- pyranoside, ginsenoside-Mc） and 20（S）-protopanaxadiol-20-O-β-D-glucopyranoside compound-K （C-K） respectively on the basis of their ^1H NMR and ^13 C NMR spectral data. Results Based on the enzymolytic kinetic curve, the transformation rate of notoginsenoside Fe reached 95% after 24 h. Conclusion The enzymatic transformation pathway of notoginsenoside Fe by β-glucanase has been proposed as notoginsenoside Fe→ginsenoside Mc→C-K.展开更多
Parvifloside (1), a new furostanol pentaglycoside, was isolated from the fresh rhizomes of Dioscorea parviflora C. T. Ting. On the basis of spectroscopic and chemical methods, its structure was elucidated as (25R)-26...Parvifloside (1), a new furostanol pentaglycoside, was isolated from the fresh rhizomes of Dioscorea parviflora C. T. Ting. On the basis of spectroscopic and chemical methods, its structure was elucidated as (25R)-26-O-β-glucopyranosyl-furost-5-en-3β,22ξ,26-triol 3-O-β-D-glucopyranosyl (1→3)-β-D-glucopyranosyl (1→4)-[α-L-rhamnopyranosyl (1→2)]-β-D-glucopyranoside. Six prosapogenins (2-7)were obtained from the enzymatic degradation of 1by cellulase, but only 3 and 4 were obtained by β-glucosidase. The structures of all compounds were determined by spectroscopic data. The activity of the isolated compounds on deformation of mycelia germinated from Pyricularia oaryzae P-2b conidia was evaluated.展开更多
[Objective] The research aimed to obtain an effectively-decomposing strain of silkworm chrysalis protein and discuss its enzymatic properties.[Method] The effectively-decomposing bacteria of protein was isolated from ...[Objective] The research aimed to obtain an effectively-decomposing strain of silkworm chrysalis protein and discuss its enzymatic properties.[Method] The effectively-decomposing bacteria of protein was isolated from the decayed silkworm chrysalis by using dilution plate and its enzymatic properties were tested after primary screening and second screening.The enzyme activity was determined and the intermediate and small molecule protein content in silkworm chrysalis was measured after solid-state fermentati...展开更多
[Objective] The aim was to obtain α-amylase producing strains with some excellent properties like high temperature resistance,strong acid resistance,strong alkali resistance,etc..[Method] α-amylase producing strains...[Objective] The aim was to obtain α-amylase producing strains with some excellent properties like high temperature resistance,strong acid resistance,strong alkali resistance,etc..[Method] α-amylase producing strains were isolated and screened; furthermore their enzymatic properties were studied.[Result] 10 strains with an obvious starch hydrolysis cycle were screened out from starch screening plate coated by diluted sample,from which 3 strains with higher α-amylase activity were screened out,that was X6,X8 and X10.As for X6,X8 and X10,their optimum pH values all belonged to neutral,and their optimum temperatures were all 60 ℃.Meanwhile,Ca^2＋ could increase their enzyme thermal stability.When the concentration of Ca^2＋ was 0.02-0.04 mol/L,the enzyme thermal stability of X6 and X8 reached the highest; When the concentration of Ca^2＋ was 0.03-0.04 mol/L,that of X10 reached the highest; When the concentration of Ca^2＋ was increased continuously,those of the 3 strains all decreased.[Conclusion] The research provides theoretical basis for satisfying the demands of different industries for α-amylase with different characteristics.展开更多
Non-aqueous phase enzymatic catalysis technology has been widely ap- plied in the area of food additives production. This paper reviewed the types of re- action medium of non-aqueous phase enzymatic catalysis reaction...Non-aqueous phase enzymatic catalysis technology has been widely ap- plied in the area of food additives production. This paper reviewed the types of re- action medium of non-aqueous phase enzymatic catalysis reaction, introduced the application of non-aqueous phase enzymatic catalysis technology in catalysis of L-ascorbic （isoascorbic） acid esters, short-chain acid esters, sugar esters, vitamin A esters, vi- tamin E esters, and other food additives, and finally predicted the prospects of non- aqueous phase enzymatic catalysis technology.展开更多
The response of enzyme and non-enzymatic antioxidants of Mn hyperaccumuator, Polygonum hydropiper （P. hydropiper）, to Mn stress was studied using hydroponics culture experiments to explore the mechanism of Mn tolera...The response of enzyme and non-enzymatic antioxidants of Mn hyperaccumuator, Polygonum hydropiper （P. hydropiper）, to Mn stress was studied using hydroponics culture experiments to explore the mechanism of Mn tolerance in this species. Results showed that both chlorophyll and carotenoid contents significantly （p〈0.05） decreased with increasing Mn treatment levels （0, 0.5, 1, 2, 4, and 8 mg/L） in hydroponics. The concentrations of malondialdehyde （MDA） and hydrogen peroxide （H202） in the root and shoot of P hydropiper were accumulated under Mn stress. Meanwhile, the anti-oxidative functions of several important enzymes, including superoxide dismutase （SOD）, catalase （CAT）, ascorbate peroxidase （APX） and peroxidase （POD） in plants were stimulated by Mn spike in leaves and roots, especially at low Mn stress; while sulfhydryl group （--SH） and glutathion （GSH） were likely involved in Mn detoxification ofP. hydropiper under high Mn stress.展开更多
Aim To evaluate the inhibitory effect of chitosan-cysteine conjugate onenzymatic degradation and hypogly-cemic enhancement effect of insulin. Methods Chitosan-cysteineconjugate was synthesized. The protective effect o...Aim To evaluate the inhibitory effect of chitosan-cysteine conjugate onenzymatic degradation and hypogly-cemic enhancement effect of insulin. Methods Chitosan-cysteineconjugate was synthesized. The protective effect of the conjugate against degradation of insulin byα-chymotrypsin and trypsin was evaluated in vitro. Insulin enteric- microspheres were prepared byusing O_1 /Q_2 emulsion solvent evaporation method. The hypoglycemic enhancement effect of theconjugate was studied by oral administration of insulin solution or enteric-microspheres to rats.Results The thiol group content of the synthesized conjugate was about 200 μmol·g^(-1) polymer,which showed a strong protective effect on insulin from enzymatic degradation in vitro. Almost allthe insulin incubated in a-chymotrypsin solution or trypsin solution without chitosan-cysteineconjugate was degraded entirely within 1 h and 5 h respectively, whereas above 75% of insulinremained in the same content of the enzymatic solution containing 4 mg·mL^(-1) conjugate. The drugloading of insulin enteric-microspheres was about 7% . In vivo experiment, chitosan-cysteineconjugate (85 μg·kg^(-1)) prolonged the hypoglycemic time of insulin solution orenteric-microspheres when administered simultaneously with the absorption enhancer SNAC. ConclusionChitosan-cysteine conjugate has a marked inhibitory effect on the enzymatic degradation of insulinin vitro, and it displays a significant hypoglycemic enhancement effect on insulin oral formulationin vivo.展开更多
[Objective] This study aimed to investigate the effects of different pretreat- ments on enzymatic saccharification of Miscanthus sinensis and improve reducing sugar yield in the enzymolysis process. [Method] M. sinens...[Objective] This study aimed to investigate the effects of different pretreat- ments on enzymatic saccharification of Miscanthus sinensis and improve reducing sugar yield in the enzymolysis process. [Method] M. sinensis was pretreated with 60Co y-ray irradiation and alkaline hydrogen peroxide, to analyze their effects on re- ducing sugar yield of enzymatic hydrolysis. [Result] After pretreatment with 400 kGy 60Co y-ray irradiation, reducing sugar yield in the enzymolysis process of M sinensis was 76.24 mg/g; after synergic pretreatment with 400 kGy 60Co y-ray irradiation and alkaline hydrogen peroxide, reducing sugar yield in the enzymolysis process of M. sinensis was 505.08 mg/g, which was improved by 5.6 times compared to that in pretreatment with 400 kGy 60Co y-ray irradiation. Based on process optimization, the optimal hydrolysis conditions were obtained： pretreatment temperature 30 ℃, NaOH concentration 1.2%, hydrogen peroxide concentration 2%, pretreatment time 6 h. [Conclusion] Synergic pretreatment with 60Co y-ray irradiation and alkaline hydrogen peroxide could significantly improve reducing sugar yield in the enzymolysis process of M. sinensis, which provided a new theoretical basis for preparing fuel ethanol with M. sinensis.展开更多
[ Objective] To study the effect of pretreatment with chemical substances on enzymatic saccharification of affalfa （ Medic, ago sativa L. ）, sorghum hybrid sudan grass [ Sorghum bicolor （ L. ） Moench x Sorghum sud...[ Objective] To study the effect of pretreatment with chemical substances on enzymatic saccharification of affalfa （ Medic, ago sativa L. ）, sorghum hybrid sudan grass [ Sorghum bicolor （ L. ） Moench x Sorghum sudanese （Piper） Stapf], erect milkvetch （Astraga/us adsurgens Pall. ） and pearl millet （ Pennisetum americanum （ L. ） Leeke）. [ Method ] The forages were pretreated with sulfuric acid at different concentration, and then the content of cellulose, hemicellulose, and lignin were detected and compared with that before pretreatment. The concentration of glucose and ethanol after different fermentation time was also determined. [ Result] After pretreatment, the content of cellulose increased, while that of hemicel- lulose and lignin decreased. After treatment with 1.0% （W/V） sulfuric acid, the four kinds of forages all had the highest concentration of ethanol in the citric acid-sodium citrate buffer system （pH 4.8）. Dudng fermentation process, the concentration of glucose and ethanol first increased and then declined, peaking respectively at 24 h and 48 h post fermentation. [Condusion] Pretreatment promotes the enzymatic saccharification and fermen- tation of alfalfa, sorehum hvbrid sudan orass. Dead millet, and erect milkvetch, and their enerov performance decreases in order.展开更多
A simulation experiment on the responses of maize (Zea mays L.) from the third leaf stage to maturity for different soil water levels (well-watered, moderately stressed, and severely stressed) was conducted by control...A simulation experiment on the responses of maize (Zea mays L.) from the third leaf stage to maturity for different soil water levels (well-watered, moderately stressed, and severely stressed) was conducted by controlling irrigation and using a mobile rain shelter in a neutral loam, meadow soil to determine the effects on leaf water status, membrane permeability and enzymatic antioxidant system for different growth stages. The results indicated that drought stress relied on drought intensity and duration, with more severe drought stress creating more serious effects on maize. Compared with well-watered conditions, during the silking and blister stages moderate stress did not significantly change the relative water content (RWC) and did change significantly the relative conductivity (RC) (P < 0.05) of the leaves; however, severe stress did significantly decrease (P < 0.01) the leaf RWC and increase (P < 0.01) membrane permeability (leaf relative conductivity). Furthermore, under severe drought stress antioxidant enzyme activities declined significantly (P < 0.01) in later stages, namely for superoxide dismutase (SOD) the tasseling and blister stages, for peroxidase (POD) the milk stage, and for catalase (CAT) during the tasseling, blister, and milk stages. Meanwhile, membrane lipid peroxidation (measured as malondialdehyde content) significantly increased (P < 0.01) in all stages.展开更多
This study focused on the changes of soil microbial diversity and potential inhibitory effects of heavy metals on soil enzymatic activities at different application rates of Cd and/or Pb. The soil used for experiments...This study focused on the changes of soil microbial diversity and potential inhibitory effects of heavy metals on soil enzymatic activities at different application rates of Cd and/or Pb. The soil used for experiments was collected from Beijing and classified as endoaquepts. Pots containing 500 g of the soil with different Cd and/or Pb application rates were incubated for a period of 0, 2, 9, 12 weeks in a glasshouse and the soil samples were analyzed for individual enzymes, including catalase, alkaline phosphatase and dehydrogenase, and the changes of microbial community structure. Results showed that heavy metals slightly inhibited the enzymatic activities in all the samples spiked with heavy metals. The extent of inhibition increased significantly with increasing level of heavy metals, and varied with the incubation periods. The soil bacterial community structure, as determined by polymerase chain reaction- denaturing gradient gel electrophoresis techniques, was different in the contaminated samples as compared to the control. The highest community change was observed in the samples amended with high level of Cd. Positive correlations were observed among the three enzymatic activities, but negative correlations were found between the amounts of the heavy metals and the enzymatic activities.展开更多
Unfavorable fishy odour is an inevitable problem in aquatic products. In the present study, headspace solid-phase mi- croextraction gas chromatography mass spectrometry （HS-SPME-GC-MS） analysis of volatiles from unt...Unfavorable fishy odour is an inevitable problem in aquatic products. In the present study, headspace solid-phase mi- croextraction gas chromatography mass spectrometry （HS-SPME-GC-MS） analysis of volatiles from untreated samples and three deodorized samples （under the optimal conditions） ofPaphia undulata enzymatic hydrolysate revealed that the compounds contrib- uting to the distinctive odor were 1-octen-3-ol, n-hexanal, n-heptanal, 2,4-heptadienal, and 2,4-decadienal, whereas n-pentanal, n-octanal, n-octanol, benzaldehyde, 2-ethylfuran and 2-pentylfuran were the main contributors to the aromatic flavor. The deodoriz- ing effects of activated carbon （AC） adsorption, yeast extract （YE） masking and tea polyphenol （TP） treatment on a P. undulata en- zymatic hydrolysate were investigated using orthogonal experiments with sensory evaluation as the index. The following optimized deodorization conditions were obtained： AC adsorption （35 mg mL-1, 80℃, 40 rain）, YE masking （7 mgmL l, 45 ℃, 30 min） and TP treatment （0.4mgmL-l, 40℃, 50min）. AC adsorption effectively removed off-flavor volatile aldehydes and ketones. YE masking modified the odor profile by increasing the relative contents of aromatic compounds and decreasing the relative contents of aldehydes and ketones. The TP treatment was not effective in reducing the odor score, but it significantly reduced the relative content of alde- hydes while increasing that of alkanes. It is also notable that TP effectively suppressed trimethylamine （TMA） formation in a P. un- dulate hydrolysate solution for a period of 72 h.展开更多
The aim of this paper is to determine the role of enzymatic vitrectomy performed by intravitreal injection of autologous plasmin enzyme(APE)in the management of diabetic retinopathy and diabetic macular edema(DME).Dia...The aim of this paper is to determine the role of enzymatic vitrectomy performed by intravitreal injection of autologous plasmin enzyme(APE)in the management of diabetic retinopathy and diabetic macular edema(DME).Diabetic patients with proliferative diabetic retinopathy or DME and evident posterior hyaloid adherence to the retinal surface were included.All cases were treated with an initial intravitreal injection of APE and reevaluated one month later,measuring changes in best-corrected visual acuity(BCVA),macular thickness and the status of the posterior hyaloid.A second APE injection was performed in cases with no evident posterior vitreous detachment(PVD)after the initial treatment.Sixty-three eyes were included in the present review.A complete PVD appeared in 38%of cases(24 eyes)after one injection of plasmin and the total increased to 51%(32 eyes)after the second injection,separated at least by one month.The central macular thickness improved in all cases(100%)and BCVA in89%.Finally,in 50%of eyes with proliferative diabetic retinopathy,a high reduction of new vessels regression was observed.Enzymatic vitrectomy could be considered a good therapeutic alternative in diabetic retinopathy and macular edema.展开更多
Corn leaf and corn stalk were pretreated with only hot water and 0.1% sulfuric acid at 160℃ or 200℃, respectively. For hot water pretreatment, the pH of corn stalk hydrolysate decreased more rapidly than that of cor...Corn leaf and corn stalk were pretreated with only hot water and 0.1% sulfuric acid at 160℃ or 200℃, respectively. For hot water pretreatment, the pH of corn stalk hydrolysate decreased more rapidly than that of corn leaf as the reaction time increased. On the contrary, the pH of corn leaf hydrolysate increased more than that of corn stalk with diluted acid addition. Increasing temperature enhanced the xylose dissolution rate and increased cellulose digestibility. Compared with hot water, 0.1% sulfuric acid addition improved the xylan removal and the enzymatic hydrolysis of both corn leaf and corn stalk residue. Much less xylan must be removed to achieve the same cellulose digestibility for the corn leaf as that for the corn stalk; 55% digestibility was obtained when only 32% xylan was removed from corn leaf, whereas corn stalk required removal of about 50% of the xylan to achieve the same di- gestibility. Overall, the descending order of enzymatic digestibility was: dilute acid hydrolysate of corn leaf > dilute acid hydrolysate of corn stalk > water-only hydrolysate of corn leaf > water-only hydrolysate of corn stalk. Finally, one separate pretreatment strategy was developed to transfer corn leaf and corn stalk to fermentable sugars for fur- ther bioenergy production.展开更多
基金湖南省教育厅基金优秀青年项目(No.22B0482)湖南科技大学博士启动基金(No.E51992 and E51993)资助。
文摘The xylitol dehydrogenase(XDH)is a crucial enzyme involved in the xylose utilization in pentose⁃catabolizing yeasts and fungi.In addition to producing xylulose,XDH can also be employed to develop a biosensor for monitoring xylitol concentration.In this study,the gene encoding the thermophilic fungus Talaromyces emersonii XDH(TeXDH)was heterologously expressed in Escherichia coli BL21(DE3)at 16℃in the soluble form.Recombinant TeXDH with high purity was purified by using a Ni⁃NTA affinity column.Size⁃exclusion chromatography and SDS⁃PAGE analysis demonstrated that the puri⁃fied recombinant TeXDH exists as a native trimer with a molecular mass of approximately 116 kD,and is composed of three identical subunits,each with a molecular weight of around 39 kD.The TeXDH strictly preferred NAD^(+)as a coenzyme to NADP^(+).The optimal temperature and pH of the TeXDH were 40℃and 10.0,respectively.After EDTA treatment,the enzyme activity of TeXDH decreased to 43.26%of the initial enzyme activity,while the divalent metal ions Mg^(2+)or Ca^(2+)could recover the enzyme activity of TeXDH,reaching 103.32%and 110.69%of the initial enzyme activity,respectively,making them the optimal divalent metal ion cofactors for TeXDH enzyme.However,the divalent metal ions of Mn^(2+),Ni^(2+),Cu^(2+),Zn^(2+),Co^(2+),and Cd^(2+)significantly inhibited the activity of TeXDH.ICP⁃MS and molecular doc⁃king studies revealed that 1 mol/L of TeXDH bound 2 mol/L Zn^(2+)ions and 1 mol/L Mg^(2+)ion.Further⁃more,TeXDH exhibited a high specificity for xylitol,laying the foundation for the development of future xylitol biosensors.
文摘Traditional biodiesel production primarily uses methanol as the acyl acceptor,but its toxicity to lipase increases process complexity and operational difficulty elevate manufacturing costs.This study aimed to explore a new method for enzymatic synthesis of biodiesel with methyl methacrylate(MMA)as acyl acceptor.Meanwhile,a 1,3-position specific lipase Lipozyme RM IM was applied as biocatalyst,which enables simultaneous production of biodiesel(FAMEs)and methacrylate fatty acid glycerides(MFAGs)via specific sn-1,3 transesterification of MMA with triglyceride.Under the optimal reaction conditions:temperature of 50℃,molar ratio of 4:1 for MMA to triglyceride,enzyme dosage of 7.5%(mass),and an extra water addition of 0.5%(mass);triglyceride conversion rate of 97%,and FAMEs yield of 65%could be obtained.Simultaneously,the multistage short-path distillation and column chromatographic method were combined used for the separation of the mixed products.Finally,the purity of FAME,MFADG,DMFAG,and MMFAG were 98%,97.8%,95.3%,and 81.78%,respectively.In this new approach,MMA demonstrates lower toxicity to lipases,allowing for straightfo rward addition of all the substrates without complex addition process,and enhancing operational feasibility.Meanwhile,the by-products of MFAGs could be applied as monomers in varnishes and protective coatings,which increased the value of the products.Thus,this investigation providing an alternative way to produce biodiesel,and providing a new pathway for the sustainable development of biodiesel.
文摘This editorial critically analyses the recent article by Jung et al,which investigates the utility of 4-hour serum amylase and lipase as early blood markers for postendoscopic retrograde cholangiopancreatography(ERCP)acute pancreatitis prediction.Although these enzymes are valuable for the early diagnosis of post-ERCP pancreatitis,they lack specificity for disease etiology and provide limited insight into the molecular mechanisms underlying disease progression.Several cytokines,notably interleukin(IL)-6,tumor necrosis factor-alpha,and IL-8,are increased in post-ERCP pancreatitis and may serve as potential predictors for disease severity.The incorporation of these biomarkers in early enzymatic biomarkers and established prognostic scoring systems could further enhance their accuracy and allow for earlier,more effective management of patients with post-ERCP pancreatitis.
基金supported by the National Key Research and Development Plan of China(grant number 2023YFC2604903)National Natural Science Foundation of China(grant number 22338013)+2 种基金Natural Science Foundation of Henan Province(grant number 242300421106)Henan Province Science and Technology Research and Development Plan Joint Fund Project(grant number 222103810063)Key Scientific and Technological Project of Education Department of Henan Province(grant number 23A210007).
文摘Enzymatic modification is an important approach to changing the structure and expanding industrial application of natural starch. In the process of starch modification, thermostable enzymes are favored owing to their compatibility with higher reaction temperatures and lower required dosage. In this study, thermostable glucoamylase from Thermothelomyces thermophilus(TtGA) was heterologously expressed in Pichia pastoris, and its effects on the structure and physicochemical properties of raw corn starch were determined. The purified TtGA had a molecular weight of approximately 66 kDa, and its optimum reaction temperature and pH were 50 ℃ and 5.0, respectively. TtGA retained > 60% of its activity following treatment at 60 ℃ for 2 h and remained stable within a pH range of 4.0–7.0 for 6 h. The enzymatic modification of raw corn starch with TtGA led to 3% hydrolysis at 50 ℃ for 24 h. In comparison with natural raw corn starch, TtGA-modified starch had a smaller particle size with an unchanged crystalline structure, increased relative crystallinity, and amylose content.Scanning electronic observation showed that larger pores were formed on the surface of starch particles, and Fourier-transform infrared spectroscopy indicated that TtGA increased the degree of order in the raw corn starch.TtGA modification caused enhanced viscosity of the raw corn starch and altered the rheological properties with decreases in storage and loss moduli, as well as shear viscosity. Moreover, TtGA treatment enhanced the thermal characteristics of the raw corn starch, and decreased gelatinization enthalpy. This study provides detailed evidence for TtGA modification of raw corn starch, which would be helpful for its practical utilization in starch modification.
基金National Science Fund for Distinguished Young Scholars of China(32425056)National Natural Science Foundation of China(U23A20250)+2 种基金the earmarked fund for CARS(CARS-45)the National Key R&D Program of China(2023YFD2400600)Sichuan Innovation Team of National Modern Agricultural Industry Technology System(SCCXTD-2024-15).
文摘Background In intensive aquaculture systems,the frequent incidence of enteritis reduces production efficiency and results in significant economic losses.Protein feeds account for 40%–60%of aquafeed expenses,and with the growth of intensive aquaculture,demand for fishmeal as a key protein source outstrips supply,driving up prices.This study investigated the therapeutic potential of reducing dietary protein levels by 3%and adding enzymatic cottonseed protein(ECP)in juvenile yellow catfish with dextran sulfate sodium(DSS)-induced enteritis.Methods A total of 1,260 healthy juvenile yellow catfish(Pelteobagrus fulvidraco),with an average body weight of 5.90±0.05 g,were randomly allocated into 7 experimental groups,each with 3 replicates.The fish were fed one of seven diets for 10 weeks:a normal-protein diet(42%;NP)and 6 low-protein diets(39%;LP)supplemented with graded levels of ECP at 0%(ECP0),1%(ECP1),2%(ECP2),3%(ECP3),4%(ECP4),and 5%(ECP5),respectively.Subsequently,48 fish from each group were selected to receive 1 mL of 6%DSS solution.Results Our findings demonstrated that:(1)The DSS+ECP0 group aggravated DSS-induced enteritis in juvenile yellow catfish compared to the DSS+NP group.(2)Dietary supplementation of ECP in LP diets significantly enhanced the enzymatic activity and levels of immunoreactive substances,including LZM,C3,C4,and ACP(P<0.05).Mechanistically,first,ECP supplementation modulated macrophage polarization by inhibiting the M1 phenotype while promoting the M2 phenotype,potentially through the JAK-STAT signaling pathway;second,dietary ECP suppressed the phosphorylation cascade of key necroptosis-related proteins,including RIP1,RIP3,and MLKL,potentially via the NF-κB and MAPK signaling pathways.(3)The DSS+ECP2 group demonstrated comparable or superior efficacy to the DSS+NP group in mitigating DSS-induced intestinal enteritis.Conclusions Our results demonstrated that ECP can alleviate DSS-induced enteritis by regulating macrophage polarization and reducing necroptosis.Furthermore,ECP supplementation effectively counteracted the exacerbation of enteritis caused by dietary protein reduction.These findings highlighted the effectiveness and feasibility of ECP in alleviating enteritis and saving protein.
基金supported by the ROP ERDF 2014-2020 Lombardy-Innovation and Competitiveness.
文摘Saponins can be potential candidates for the development of safe biopesticides,due to their widely acknowledged insecticidal,fungicidal and nematicidal activity,but information on their effects on soil biological properties is still limited.This study aimed to investigate the short-term fate of saponins from Medicago sativa in soil and their dose-effect relationship with microbial biomass and selected enzyme activities in soils with different origin,physical and chemical properties.Microbial degradation of total saponins ranged from 46%to 91%,according to soil characteristics,within 28 days from their incorporation into the soil.Both saponin glycosidic chains and triterpenic aglycones were also microbially degraded,though by dynamics changing among the different soils.In all soils,M.sativa saponins significantly reduced microbial biomass at rates of 10 and 20 mg saponin mixture per g of soil.Microbial enzymatic activities were less affected as indicating an adaptive response of soil microbial communities to the presence of saponins.
文摘Aim An industrial enzyme β-glucanase was used to transfortn notoginsenoside Fe for the first time. Methods Notoginsenoside Fe was isolated from the leave saponin of Panax notoginseng （Burk.） Chen FH. The enzymatically transformed compounds were detected by HPLC and two transformed compounds were identified as 20 （S） -protopanaxadiol-20- O- α-L-arabinofuranosyl （ 1→6 ） - β-gluco- pyranoside, ginsenoside-Mc） and 20（S）-protopanaxadiol-20-O-β-D-glucopyranoside compound-K （C-K） respectively on the basis of their ^1H NMR and ^13 C NMR spectral data. Results Based on the enzymolytic kinetic curve, the transformation rate of notoginsenoside Fe reached 95% after 24 h. Conclusion The enzymatic transformation pathway of notoginsenoside Fe by β-glucanase has been proposed as notoginsenoside Fe→ginsenoside Mc→C-K.
文摘Parvifloside (1), a new furostanol pentaglycoside, was isolated from the fresh rhizomes of Dioscorea parviflora C. T. Ting. On the basis of spectroscopic and chemical methods, its structure was elucidated as (25R)-26-O-β-glucopyranosyl-furost-5-en-3β,22ξ,26-triol 3-O-β-D-glucopyranosyl (1→3)-β-D-glucopyranosyl (1→4)-[α-L-rhamnopyranosyl (1→2)]-β-D-glucopyranoside. Six prosapogenins (2-7)were obtained from the enzymatic degradation of 1by cellulase, but only 3 and 4 were obtained by β-glucosidase. The structures of all compounds were determined by spectroscopic data. The activity of the isolated compounds on deformation of mycelia germinated from Pyricularia oaryzae P-2b conidia was evaluated.
基金Supported by Agricultural Key Project of Guangdong Province(2007A0201000043)Key Bidding Projects in Key Fields of Guangdong and Hongkong(2006A25001002)Special Fund for the Construction of National Modern Agro-industry Technology System~~
文摘[Objective] The research aimed to obtain an effectively-decomposing strain of silkworm chrysalis protein and discuss its enzymatic properties.[Method] The effectively-decomposing bacteria of protein was isolated from the decayed silkworm chrysalis by using dilution plate and its enzymatic properties were tested after primary screening and second screening.The enzyme activity was determined and the intermediate and small molecule protein content in silkworm chrysalis was measured after solid-state fermentati...
基金Supported by Project Funded by Biotechnology Key Laboratory of Fermentation and Brewing Engineering of State Ethnic Affairs Commission (2005Y027)~~
文摘[Objective] The aim was to obtain α-amylase producing strains with some excellent properties like high temperature resistance,strong acid resistance,strong alkali resistance,etc..[Method] α-amylase producing strains were isolated and screened; furthermore their enzymatic properties were studied.[Result] 10 strains with an obvious starch hydrolysis cycle were screened out from starch screening plate coated by diluted sample,from which 3 strains with higher α-amylase activity were screened out,that was X6,X8 and X10.As for X6,X8 and X10,their optimum pH values all belonged to neutral,and their optimum temperatures were all 60 ℃.Meanwhile,Ca^2＋ could increase their enzyme thermal stability.When the concentration of Ca^2＋ was 0.02-0.04 mol/L,the enzyme thermal stability of X6 and X8 reached the highest; When the concentration of Ca^2＋ was 0.03-0.04 mol/L,that of X10 reached the highest; When the concentration of Ca^2＋ was increased continuously,those of the 3 strains all decreased.[Conclusion] The research provides theoretical basis for satisfying the demands of different industries for α-amylase with different characteristics.
基金Supported by Jiangxi Provincial Engineering & Technology Research Center for Food Additives Bio-ProductionScience & Technology Platform Construction Program of Jiangxi Province (2010DTZ01900)+1 种基金Priority Academic Program Development of Jiangsu Higher Education InstitutionsResearch Foundation for Advanced Talents of Jiangsu University (08JDG029)~~
文摘Non-aqueous phase enzymatic catalysis technology has been widely ap- plied in the area of food additives production. This paper reviewed the types of re- action medium of non-aqueous phase enzymatic catalysis reaction, introduced the application of non-aqueous phase enzymatic catalysis technology in catalysis of L-ascorbic （isoascorbic） acid esters, short-chain acid esters, sugar esters, vitamin A esters, vi- tamin E esters, and other food additives, and finally predicted the prospects of non- aqueous phase enzymatic catalysis technology.
基金Project(41161057)supported by the National Natural Science Foundation of ChinaProject(Guikezhuan 14122008-2)supported by Guangxi Provincial Science and Technology Development,China+2 种基金Project(2014GXNSFAA118303)supported by the Natural Science Foundation of Guangxi Province,ChinaProjects(YRHJ15K002,YRHJ15Z026)supported by Key Laboratory of Karst Ecology and Environment Change of Guangxi Normal University,ChinaProject(2016JJ6135)supported by the Natural Science Foundation of Hunan Province,China
文摘The response of enzyme and non-enzymatic antioxidants of Mn hyperaccumuator, Polygonum hydropiper （P. hydropiper）, to Mn stress was studied using hydroponics culture experiments to explore the mechanism of Mn tolerance in this species. Results showed that both chlorophyll and carotenoid contents significantly （p〈0.05） decreased with increasing Mn treatment levels （0, 0.5, 1, 2, 4, and 8 mg/L） in hydroponics. The concentrations of malondialdehyde （MDA） and hydrogen peroxide （H202） in the root and shoot of P hydropiper were accumulated under Mn stress. Meanwhile, the anti-oxidative functions of several important enzymes, including superoxide dismutase （SOD）, catalase （CAT）, ascorbate peroxidase （APX） and peroxidase （POD） in plants were stimulated by Mn spike in leaves and roots, especially at low Mn stress; while sulfhydryl group （--SH） and glutathion （GSH） were likely involved in Mn detoxification ofP. hydropiper under high Mn stress.
文摘Aim To evaluate the inhibitory effect of chitosan-cysteine conjugate onenzymatic degradation and hypogly-cemic enhancement effect of insulin. Methods Chitosan-cysteineconjugate was synthesized. The protective effect of the conjugate against degradation of insulin byα-chymotrypsin and trypsin was evaluated in vitro. Insulin enteric- microspheres were prepared byusing O_1 /Q_2 emulsion solvent evaporation method. The hypoglycemic enhancement effect of theconjugate was studied by oral administration of insulin solution or enteric-microspheres to rats.Results The thiol group content of the synthesized conjugate was about 200 μmol·g^(-1) polymer,which showed a strong protective effect on insulin from enzymatic degradation in vitro. Almost allthe insulin incubated in a-chymotrypsin solution or trypsin solution without chitosan-cysteineconjugate was degraded entirely within 1 h and 5 h respectively, whereas above 75% of insulinremained in the same content of the enzymatic solution containing 4 mg·mL^(-1) conjugate. The drugloading of insulin enteric-microspheres was about 7% . In vivo experiment, chitosan-cysteineconjugate (85 μg·kg^(-1)) prolonged the hypoglycemic time of insulin solution orenteric-microspheres when administered simultaneously with the absorption enhancer SNAC. ConclusionChitosan-cysteine conjugate has a marked inhibitory effect on the enzymatic degradation of insulinin vitro, and it displays a significant hypoglycemic enhancement effect on insulin oral formulationin vivo.
基金Supported by National High Technology Research and Development Program of China(863 Program)(2012AA101804)~~
文摘[Objective] This study aimed to investigate the effects of different pretreat- ments on enzymatic saccharification of Miscanthus sinensis and improve reducing sugar yield in the enzymolysis process. [Method] M. sinensis was pretreated with 60Co y-ray irradiation and alkaline hydrogen peroxide, to analyze their effects on re- ducing sugar yield of enzymatic hydrolysis. [Result] After pretreatment with 400 kGy 60Co y-ray irradiation, reducing sugar yield in the enzymolysis process of M sinensis was 76.24 mg/g; after synergic pretreatment with 400 kGy 60Co y-ray irradiation and alkaline hydrogen peroxide, reducing sugar yield in the enzymolysis process of M. sinensis was 505.08 mg/g, which was improved by 5.6 times compared to that in pretreatment with 400 kGy 60Co y-ray irradiation. Based on process optimization, the optimal hydrolysis conditions were obtained： pretreatment temperature 30 ℃, NaOH concentration 1.2%, hydrogen peroxide concentration 2%, pretreatment time 6 h. [Conclusion] Synergic pretreatment with 60Co y-ray irradiation and alkaline hydrogen peroxide could significantly improve reducing sugar yield in the enzymolysis process of M. sinensis, which provided a new theoretical basis for preparing fuel ethanol with M. sinensis.
文摘[ Objective] To study the effect of pretreatment with chemical substances on enzymatic saccharification of affalfa （ Medic, ago sativa L. ）, sorghum hybrid sudan grass [ Sorghum bicolor （ L. ） Moench x Sorghum sudanese （Piper） Stapf], erect milkvetch （Astraga/us adsurgens Pall. ） and pearl millet （ Pennisetum americanum （ L. ） Leeke）. [ Method ] The forages were pretreated with sulfuric acid at different concentration, and then the content of cellulose, hemicellulose, and lignin were detected and compared with that before pretreatment. The concentration of glucose and ethanol after different fermentation time was also determined. [ Result] After pretreatment, the content of cellulose increased, while that of hemicel- lulose and lignin decreased. After treatment with 1.0% （W/V） sulfuric acid, the four kinds of forages all had the highest concentration of ethanol in the citric acid-sodium citrate buffer system （pH 4.8）. Dudng fermentation process, the concentration of glucose and ethanol first increased and then declined, peaking respectively at 24 h and 48 h post fermentation. [Condusion] Pretreatment promotes the enzymatic saccharification and fermen- tation of alfalfa, sorehum hvbrid sudan orass. Dead millet, and erect milkvetch, and their enerov performance decreases in order.
基金Project supported by the National Key Basic Research Support Foundation of China (No. G1999043407)the National Natural Science Foundation of China (No. 40231018)
文摘A simulation experiment on the responses of maize (Zea mays L.) from the third leaf stage to maturity for different soil water levels (well-watered, moderately stressed, and severely stressed) was conducted by controlling irrigation and using a mobile rain shelter in a neutral loam, meadow soil to determine the effects on leaf water status, membrane permeability and enzymatic antioxidant system for different growth stages. The results indicated that drought stress relied on drought intensity and duration, with more severe drought stress creating more serious effects on maize. Compared with well-watered conditions, during the silking and blister stages moderate stress did not significantly change the relative water content (RWC) and did change significantly the relative conductivity (RC) (P < 0.05) of the leaves; however, severe stress did significantly decrease (P < 0.01) the leaf RWC and increase (P < 0.01) membrane permeability (leaf relative conductivity). Furthermore, under severe drought stress antioxidant enzyme activities declined significantly (P < 0.01) in later stages, namely for superoxide dismutase (SOD) the tasseling and blister stages, for peroxidase (POD) the milk stage, and for catalase (CAT) during the tasseling, blister, and milk stages. Meanwhile, membrane lipid peroxidation (measured as malondialdehyde content) significantly increased (P < 0.01) in all stages.
基金Project supported by the Key Project of Chinese Academy of Sciences(No. KZCX3-SW-431, KZCX2-YW-408)the National Natural Sci-ence Foundation of China (No. 40321101, 40571082).
文摘This study focused on the changes of soil microbial diversity and potential inhibitory effects of heavy metals on soil enzymatic activities at different application rates of Cd and/or Pb. The soil used for experiments was collected from Beijing and classified as endoaquepts. Pots containing 500 g of the soil with different Cd and/or Pb application rates were incubated for a period of 0, 2, 9, 12 weeks in a glasshouse and the soil samples were analyzed for individual enzymes, including catalase, alkaline phosphatase and dehydrogenase, and the changes of microbial community structure. Results showed that heavy metals slightly inhibited the enzymatic activities in all the samples spiked with heavy metals. The extent of inhibition increased significantly with increasing level of heavy metals, and varied with the incubation periods. The soil bacterial community structure, as determined by polymerase chain reaction- denaturing gradient gel electrophoresis techniques, was different in the contaminated samples as compared to the control. The highest community change was observed in the samples amended with high level of Cd. Positive correlations were observed among the three enzymatic activities, but negative correlations were found between the amounts of the heavy metals and the enzymatic activities.
基金supported by the Public Science and Technology Research Funds Projects of Ocean (No.201305018)the National Key Technology Research and Development Program for the 12th Five-Year Plan (No.2012BAD33B10)+3 种基金the National Natural Science Foundation of Guangdong, China (Nos. 2014A 030310351 and 2014A030310338)the Innovative Development of Marine Economy Regional Demonstration Projects of Guangdong (Nos.SZHY2012-B01-004 and GD2013-B03-001)the Science and Technology Planning Project of Guangdong Province, China (Nos.2013B 090800002 and 2015B090904003)the National Science Foundation for Young Scientists of China (No.31101271)
文摘Unfavorable fishy odour is an inevitable problem in aquatic products. In the present study, headspace solid-phase mi- croextraction gas chromatography mass spectrometry （HS-SPME-GC-MS） analysis of volatiles from untreated samples and three deodorized samples （under the optimal conditions） ofPaphia undulata enzymatic hydrolysate revealed that the compounds contrib- uting to the distinctive odor were 1-octen-3-ol, n-hexanal, n-heptanal, 2,4-heptadienal, and 2,4-decadienal, whereas n-pentanal, n-octanal, n-octanol, benzaldehyde, 2-ethylfuran and 2-pentylfuran were the main contributors to the aromatic flavor. The deodoriz- ing effects of activated carbon （AC） adsorption, yeast extract （YE） masking and tea polyphenol （TP） treatment on a P. undulata en- zymatic hydrolysate were investigated using orthogonal experiments with sensory evaluation as the index. The following optimized deodorization conditions were obtained： AC adsorption （35 mg mL-1, 80℃, 40 rain）, YE masking （7 mgmL l, 45 ℃, 30 min） and TP treatment （0.4mgmL-l, 40℃, 50min）. AC adsorption effectively removed off-flavor volatile aldehydes and ketones. YE masking modified the odor profile by increasing the relative contents of aromatic compounds and decreasing the relative contents of aldehydes and ketones. The TP treatment was not effective in reducing the odor score, but it significantly reduced the relative content of alde- hydes while increasing that of alkanes. It is also notable that TP effectively suppressed trimethylamine （TMA） formation in a P. un- dulate hydrolysate solution for a period of 72 h.
文摘The aim of this paper is to determine the role of enzymatic vitrectomy performed by intravitreal injection of autologous plasmin enzyme(APE)in the management of diabetic retinopathy and diabetic macular edema(DME).Diabetic patients with proliferative diabetic retinopathy or DME and evident posterior hyaloid adherence to the retinal surface were included.All cases were treated with an initial intravitreal injection of APE and reevaluated one month later,measuring changes in best-corrected visual acuity(BCVA),macular thickness and the status of the posterior hyaloid.A second APE injection was performed in cases with no evident posterior vitreous detachment(PVD)after the initial treatment.Sixty-three eyes were included in the present review.A complete PVD appeared in 38%of cases(24 eyes)after one injection of plasmin and the total increased to 51%(32 eyes)after the second injection,separated at least by one month.The central macular thickness improved in all cases(100%)and BCVA in89%.Finally,in 50%of eyes with proliferative diabetic retinopathy,a high reduction of new vessels regression was observed.Enzymatic vitrectomy could be considered a good therapeutic alternative in diabetic retinopathy and macular edema.
基金Supported by the National Natural Science Foundation of China (No.29976045).
文摘Corn leaf and corn stalk were pretreated with only hot water and 0.1% sulfuric acid at 160℃ or 200℃, respectively. For hot water pretreatment, the pH of corn stalk hydrolysate decreased more rapidly than that of corn leaf as the reaction time increased. On the contrary, the pH of corn leaf hydrolysate increased more than that of corn stalk with diluted acid addition. Increasing temperature enhanced the xylose dissolution rate and increased cellulose digestibility. Compared with hot water, 0.1% sulfuric acid addition improved the xylan removal and the enzymatic hydrolysis of both corn leaf and corn stalk residue. Much less xylan must be removed to achieve the same cellulose digestibility for the corn leaf as that for the corn stalk; 55% digestibility was obtained when only 32% xylan was removed from corn leaf, whereas corn stalk required removal of about 50% of the xylan to achieve the same di- gestibility. Overall, the descending order of enzymatic digestibility was: dilute acid hydrolysate of corn leaf > dilute acid hydrolysate of corn stalk > water-only hydrolysate of corn leaf > water-only hydrolysate of corn stalk. Finally, one separate pretreatment strategy was developed to transfer corn leaf and corn stalk to fermentable sugars for fur- ther bioenergy production.
