The chemical synthesis of Guanine arabinoside （ara-G） is extremely complex, time-consuming, and seriously polluted. A two-step enzymatic synthesis process was developed to acquire ara-G easily. 2,6-Diaminopurine ara...The chemical synthesis of Guanine arabinoside （ara-G） is extremely complex, time-consuming, and seriously polluted. A two-step enzymatic synthesis process was developed to acquire ara-G easily. 2,6-Diaminopurine arabinoside （ara-DA） was first synthesized with purine nucleoside phosphorylase and pyrimidine nucleoside phosphorylase produced by Enterobacter aerogenes DGW-07. The conversion yield of ara-DA could reach above 90% when the reaction liquid contained 30 mmol·L^-1 uracil arabinoside as arabinose donor, 10 mmol·L^- 1 2,6-diaminopurine as arabinose acceptor in pH 7.0 20 mmol·L^-1 phosphate buffer, and reacted at 60℃ for 48h. Then, ara-DA was effectively transformed into ara-G with adenylate deaminase produced by Aspergillus oryzae DAW-01. The total process had no complex separation and purification.展开更多
We report a case of candidal liver abscesses and concomitant candidal cholecystitis in a diabetic patient, in whom differences were noted relative to those found in patients with hematologic malignancies. In our case,...We report a case of candidal liver abscesses and concomitant candidal cholecystitis in a diabetic patient, in whom differences were noted relative to those found in patients with hematologic malignancies. In our case, the proposed entry route of infection is ascending retrograde from the biliary tract. Bile and aspirated pus culture repeatedly tested positive, and blood negative, for Candida albicans and Candida glabrata. Cholecystitis was cured by percutaneous gallbladder drainage and amphotericin B therapy. The liver abscesses were successfully treated by a cumulative dosage of 750 mg amphotericin B. We conclude that in cases involving less immunocompromised patients and those without candidemia, a lower dosage of amphotericin B may be adequate in treating candidal liver abscesses.展开更多
Arbutin was synthesized from glucose by two-step reaction below: (a) 2,3,4,6-tetra-O-acetyl-α-D-glucosyl chloride or bromide was prepared by glucose and acetyl halide (chloride or bromide), (b) 2,3,4,6-tetra-O-ace-t...Arbutin was synthesized from glucose by two-step reaction below: (a) 2,3,4,6-tetra-O-acetyl-α-D-glucosyl chloride or bromide was prepared by glucose and acetyl halide (chloride or bromide), (b) 2,3,4,6-tetra-O-ace-tyl-α-D-glucosyl halide (Cl, Br) reacted with hydroquinone, methanol as solvent at pH=9.5-10.0.展开更多
A hybrid GMDH neural network model has been developed in order to predict the partition coefficients of invertase from Baker's yeast. ATPS experiments were carried out changing the molar average mass of PEG(1500–...A hybrid GMDH neural network model has been developed in order to predict the partition coefficients of invertase from Baker's yeast. ATPS experiments were carried out changing the molar average mass of PEG(1500–6000 Da), p H(4.0–7.0), percentage of PEG(10.0–20.0 w/w), percentage of MgSO_4(8.0–16.0 w/w), percentage of the cell homogenate(10.0–20.0 w/w) and the percentage of MnSO_4(0–5.0 w/w) added as cosolute. The network evaluation was carried out comparing the partition coefficients obtained from the hybrid GMDH neural network with the experimental data using different statistical metrics. The hybrid GMDH neural network model showed better fitting(AARD = 32.752%) as well as good generalization capacity of the partition coefficients of the ATPS than the original GMDH network approach and a BPANN model. Therefore hybrid GMDH neural network model appears as a powerful tool for predicting partition coefficients during downstream processing of biomolecules.展开更多
In the present study, we aimed to explore the structure-activity relationship for the new amphiphilic material rhamnoside with antibacterial biofilm activity, and provide the basis for selecting rhamnoside with the op...In the present study, we aimed to explore the structure-activity relationship for the new amphiphilic material rhamnoside with antibacterial biofilm activity, and provide the basis for selecting rhamnoside with the optimum antibacterial biofilm activity. A series of alkyl rhamnosides with different carbon chain lengths were obtained by a simple and effective synthesis method. The structure was characterized by ~1H NMR spectrum, and their critical micelle concentration(CMC) was measured by fluorescence probe method. The hydrophilic and lipophilic balance(HLB) value was obtained by calculation. The minimal inhibitory concentration(MIC) of Staphylococcus aureus was determined by the broth double dilution method. The effect of biofilm inhibition and biofilm disruption was assayed by crystal violet method. The results showed that with the increase of carbon chain length, the CMC and HLB of alkyl rhamnosides displayed a linear downward trend, indicating that the lipophilicity and surface activity of the alkyl rhamnoside were increased. At the same time, the antibacterial activity in vitro produced the maximum, ie, 12-hydroxydecanoyl rhamnoside had the strongest antibacterial activity in vitro. Similarly, this material also exhibited the strongest antibacterial biofilm activity in vitro. The results of this study demonstrated that the most potent active material was obtained through the structure-activity relationship and it could be applied antibacterial biofilms in clinical practice.展开更多
基金Supported by the Innovation Fund for Technology Based Firms from Ministry of Science and Technology of China(07C26213101283)
文摘The chemical synthesis of Guanine arabinoside （ara-G） is extremely complex, time-consuming, and seriously polluted. A two-step enzymatic synthesis process was developed to acquire ara-G easily. 2,6-Diaminopurine arabinoside （ara-DA） was first synthesized with purine nucleoside phosphorylase and pyrimidine nucleoside phosphorylase produced by Enterobacter aerogenes DGW-07. The conversion yield of ara-DA could reach above 90% when the reaction liquid contained 30 mmol·L^-1 uracil arabinoside as arabinose donor, 10 mmol·L^- 1 2,6-diaminopurine as arabinose acceptor in pH 7.0 20 mmol·L^-1 phosphate buffer, and reacted at 60℃ for 48h. Then, ara-DA was effectively transformed into ara-G with adenylate deaminase produced by Aspergillus oryzae DAW-01. The total process had no complex separation and purification.
文摘We report a case of candidal liver abscesses and concomitant candidal cholecystitis in a diabetic patient, in whom differences were noted relative to those found in patients with hematologic malignancies. In our case, the proposed entry route of infection is ascending retrograde from the biliary tract. Bile and aspirated pus culture repeatedly tested positive, and blood negative, for Candida albicans and Candida glabrata. Cholecystitis was cured by percutaneous gallbladder drainage and amphotericin B therapy. The liver abscesses were successfully treated by a cumulative dosage of 750 mg amphotericin B. We conclude that in cases involving less immunocompromised patients and those without candidemia, a lower dosage of amphotericin B may be adequate in treating candidal liver abscesses.
文摘Arbutin was synthesized from glucose by two-step reaction below: (a) 2,3,4,6-tetra-O-acetyl-α-D-glucosyl chloride or bromide was prepared by glucose and acetyl halide (chloride or bromide), (b) 2,3,4,6-tetra-O-ace-tyl-α-D-glucosyl halide (Cl, Br) reacted with hydroquinone, methanol as solvent at pH=9.5-10.0.
基金CAPES and Brazilian National Council of Research (CNPq) (Grant 407684/2013-1) for the financial support
文摘A hybrid GMDH neural network model has been developed in order to predict the partition coefficients of invertase from Baker's yeast. ATPS experiments were carried out changing the molar average mass of PEG(1500–6000 Da), p H(4.0–7.0), percentage of PEG(10.0–20.0 w/w), percentage of MgSO_4(8.0–16.0 w/w), percentage of the cell homogenate(10.0–20.0 w/w) and the percentage of MnSO_4(0–5.0 w/w) added as cosolute. The network evaluation was carried out comparing the partition coefficients obtained from the hybrid GMDH neural network with the experimental data using different statistical metrics. The hybrid GMDH neural network model showed better fitting(AARD = 32.752%) as well as good generalization capacity of the partition coefficients of the ATPS than the original GMDH network approach and a BPANN model. Therefore hybrid GMDH neural network model appears as a powerful tool for predicting partition coefficients during downstream processing of biomolecules.
基金National Natural Science Foundation of China(Grant No.81573381)CAMS Initiative for Innovative Medicine(Grant No.CAMS-I2M-1-012)
文摘In the present study, we aimed to explore the structure-activity relationship for the new amphiphilic material rhamnoside with antibacterial biofilm activity, and provide the basis for selecting rhamnoside with the optimum antibacterial biofilm activity. A series of alkyl rhamnosides with different carbon chain lengths were obtained by a simple and effective synthesis method. The structure was characterized by ~1H NMR spectrum, and their critical micelle concentration(CMC) was measured by fluorescence probe method. The hydrophilic and lipophilic balance(HLB) value was obtained by calculation. The minimal inhibitory concentration(MIC) of Staphylococcus aureus was determined by the broth double dilution method. The effect of biofilm inhibition and biofilm disruption was assayed by crystal violet method. The results showed that with the increase of carbon chain length, the CMC and HLB of alkyl rhamnosides displayed a linear downward trend, indicating that the lipophilicity and surface activity of the alkyl rhamnoside were increased. At the same time, the antibacterial activity in vitro produced the maximum, ie, 12-hydroxydecanoyl rhamnoside had the strongest antibacterial activity in vitro. Similarly, this material also exhibited the strongest antibacterial biofilm activity in vitro. The results of this study demonstrated that the most potent active material was obtained through the structure-activity relationship and it could be applied antibacterial biofilms in clinical practice.
