The alpha-amylase (EC 3.2.1.1) from the Gram-positive Alicyclobacillus acidocaldarius was one kind of thermoacidophilic enzyme, with optimal temperature and pH of 75 degrees C and 3, respectively. The nucleotide sequence of the gene amy was cloned by PCR. The gene amy was 3901bp long, comprising one open reading frame encoding a polypeptide of 1301 amino acids. The calculated molecular weight of the alpha-amylase AMY was about 140kD. The gene amy was expressed in E. coli BL21 (DE3) and Pichia pastoris respectively, and both of the cloned proteins had bioactivity. The activity of amylase expressed in P. pastoris was further testified by amylase activity staining. The alpha-amylase expressed in P. pastoris had been purified and characterized. The apparent molecular weight of that was about 160kD according to SDS-PAGE. The optimum of pH for the enzyme was pH 3.2 as the native enzyme was; but the optimum of temperature was 65 degrees C and a little lower than that of the native enzyme. Above 50% of relative activity remained after incubation for 30 minutes in 70 degrees C. So the enzyme expressed by P. pastoris was also thermoacidophilic. Moreover some sequence was cloned by PCR, which ranged from + 1174 bp to + 3288 bp in the gene amy, encoding 705 amino acids with the calculated molecular weight of 79kD. The truncated gene amy' was expressed in E. coli BL21 (DE3) induced by 1 mmol/L IPTG, and the expressed enzyme also retained alpha-amylase activity.
Bacillus ; enzymology ; genetics ; Bacterial Proteins ; genetics ; isolation & purification ; metabolism ; Cloning, Molecular ; Escherichia coli ; genetics ; metabolism ; Genetic Vectors ; genetics ; Pichia ; genetics ; metabolism ; alpha-Amylases ; genetics ; isolation & purification ; metabolism

We report electroversion in treatment of atrial fibrillation (AF) and atrioventricular nodal reentry tachycardia (AVNRT) in a patient with Wolff-Parkinson-White syndrome and cervical spinal cord injury. At first, the patient sustained respiratory failure and weak cough reflex, thereafter repeated bronchoscopy was used to aspirate the sputum as well as control the pneumonia, which resulted in arrhythmia (AF and AVNRT). Two doses of intravenous amiodarone failed to correct the arrhythmia. After restoration of sinus rhythm by electroversion, he was successfully weaned from mechanical ventilation and discharged from the intensive care unit without recurrent arrhythmia.
Atrial Fibrillation ; complications ; therapy ; Bronchoscopy ; Cervical Vertebrae ; injuries ; Electric Countershock ; Electrocardiography ; Humans ; Male ; Middle Aged ; Respiration, Artificial ; Spinal Cord Injuries ; complications ; Wolff-Parkinson-White Syndrome ; complications

The hybrid xylanase TB was constructed by the substitution of the N-terminus segment of the Streptomyces olivaceoviridis xylanase XYNB with corresponding region of Thermomonosporafusca xylanase TfxA. The hybrid gene tb, encoding the TB, was correctly expressed in Escherichia coli BL21 and Pichia pastoris GS115. TB was purified and its enzymatic properties were determined. The results revealed that the optimal temperature and optimal pH of TB were at 70 degrees C and 6.0, which have been obviously improved compared with those of XYNB. The thermostability of TB were all about six-fold of XYNB's after incubating the properly diluted enzyme solutions at 80 degrees C and 90 degrees C for 3min, respectively. The pH stability of TB was 5 to approximately 9, which was narrower than that of XYNB. Still, TB remains a high specific activity as XYNB does. Analysis of a homology modeling and sequence similarity were used to reveal the factors influencing the enzymatic properties of TB and the discussion for the relationship between structure and function of xylanase was given.
Amino Acid Sequence ; Base Sequence ; Desulfurococcaceae ; enzymology ; genetics ; Endo-1,4-beta Xylanases ; genetics ; metabolism ; Enzyme Stability ; Escherichia coli ; enzymology ; genetics ; Hot Temperature ; Molecular Sequence Data ; Pichia ; enzymology ; genetics ; Protein Engineering ; methods ; Recombinant Fusion Proteins ; genetics ; metabolism ; Streptomyces ; enzymology ; genetics ; Structure-Activity Relationship

In order to improve the fermentation potency of phytase in recombinant host and decrease the production cost, the pichia expression vector pGAPZalpha-A was modified by introduction of an AOX1 promoter from vector pPIC9 and the resulted vector pAOXZalpha is an methanol induced vector. After that, a phytase gene appA-m was cloned into pAOXZalpha to construct the recombinant vector pAOXZalpha-appA-m. The recombinant Pichia pastoris 74#, which already contains one copy of appA-m and its fermentation potency exceeded 7.5 x 10(6) IU/mL, was used as the host strain for the transformation of pAOXZalpha-appA-m. The Pichia pastoris transformants were gained by electroporation. PCR results indicated that the appA-m expression box has integrated into the genome of Pichia pastoris and the original construction of phytase gene has not changed. SDS-PAGE analysis revealed that phytase was overexpressed and secreted into the medium supernatant. Recombinants with high expression level were screened and used for fermentation. In 5L fermentor, the expression level of phytase protein achieved 4 mg/mL and the phytase activity (fermentation potency) exceeded 1.2 x 10(7) IU/mL, which was about 1.6-fold compared with that of the host strain 74#. Moreover, the improved recombinant Pichia pastoris is excellent at expression stability and heredity stability.
6-Phytase ; genetics ; Fermentation ; Gene Dosage ; Pichia ; genetics ; Plasmids ; Polymerase Chain Reaction ; Recombination, Genetic

OBJECTIVETo construct glypican-3 (GPC3)-green fluorescent protein eukaryotic expression vector pEGFP-c3-GPC3, and analyze the effect of GPC3 on the proliferation of human hepatoma cell line MHCC-97L.

METHODSThe eukaryotic expression vector pEGFP-c3-GPC3 was constructed with recombinant DNA technique and transfected into MHCC-97L cells via Lipofectamine 2000. The cells stably expressing GPC3 were screened by flow cytometry and G418. The mRNA expression of GPC3 was detected by RT-QPCR method, and the protein expression by Western blotting and fluorescence microscope. The effect of GPC3 gene on the growth of the cells was examined by MTT assay.

RESULTSRestriction endonuclease analysis and DNA sequencing verified correct construction of the recombinant plasmid. The green fluorescence was detected in the transfected MHCC-97L cells under fluorescence microscope. RT-QPCR and Western blotting both confirmed successful expression of GPC3 in MHCC-97L cells. The growth curve showed a significant acceleration of the proliferation of the transfected MHCC97-Lsol;GPC3 cells as compared with MHCC97-L and MHCC97-L/C3 cells (P<0.001).

CONCLUSIONWe have successfully constructed the eukaryotic expression vector pEGFR-c3-GPC3, which allows stable GPC3 expression in MHCC97-L/GPC3 cells. The upregulation of GPC3 expression can stimulate the growth of hepatoma cell line MHCC97-L in vitro.

Carcinoma, Hepatocellular ; pathology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Genetic Vectors ; Glypicans ; pharmacology ; Green Fluorescent Proteins ; genetics ; Humans ; Liver Neoplasms ; pathology ; Plasmids ; Transfection

OBJECTIVETo evaluate the overall diet quality and diet model of labor workers in Shenzhen using Chinese Diet Balance Index (DBI).

METHODSIn May 2009, 14 canteens from Baoan, Longgang and Nanshan districts were selected by stratified random sampling and 60 workers were randomly selected from each canteen by using random number method. Diet measurements were carried out among the 840 labor workers. Diet quality was evaluated by using DBI scoring and evaluating system.

RESULTSThe median values of labor workers' food intakes of cereal and meat & poultry were 483.8 and 121.7 g/d, which were more than the recommended amounts of their intakes of Chinese residents (cereal: 250 - 400 g/d, meat & poultry: 50 -70 g/d). The median values of the labor workers' intakes of fruit, dairy and eggs were 37.3, 20.6 and 23.5 g/d,which were less than recommended amounts in fruits (200 - 400 g/d), dairy (300 g/d) and eggs (25 - 50 g/d). The DBI-HBS scores of males and females in Shenzhen migrant workers were 24.4 +/- 6.1 and 22.6 +/- 6.3, respectively with a statistically significant difference (t = 4.21, P < 0.01). DBI-HBS scores of < 20 age group, 20 - 29 age group, 30 - 39 age group and > or = 40 age group in labor workers were 12.7 +/- 5.9, 11.3 +/- 6.3, 12.8 +/- 6.4 and 11.2 +/- 5.6 respectively (F = 3.67, P = 0.01). There were 7 dietary patterns among labor workers in this survey. Nearly 8.2% (68/830) of them belonged to Pattern A. Pattern B and E were the main dietary patterns, which accounted for 37.3% (310/830) and 31.0% (257/830) of the total population.

CONCLUSIONDBI can describe and evaluate the overall dietary quality and the major problem of the dietary patterns in labor workers. It is necessary to strength nutritional education to increase the intake of fruits, milk and eggs to improve nutritional status in labor workers in Shenzhen.

Adolescent ; Adult ; Dairy Products ; Diet ; statistics & numerical data ; Diet Surveys ; Eggs ; Feeding Behavior ; Female ; Fruit ; Humans ; Male ; Meat ; Middle Aged ; Nutritional Status ; Young Adult

Aspergillus fumigatus wild-type phytase has many favorable properties, such as a good thermorstability and a broad pH optimum. However, the specific activity of the enzyme is relative low. A. fumigatus Q23L phytase resulted in a remarkable increase in specific activity around pH4.5 - 7.0, but the pH stability of Q23L was lower than A. fumigatus wild-type phytase. To increase the pH stability of Q23L, the mutant Q23LG272E was constructed by site-directed mutagenesis with PCR. The gene of A. fumigatus wild-type phytase and the mutant genes encoding the Q23LG272E and the Q23L were correctly expressed in Pichia pastoris GS115. Enzymes were purified and their enzymatic properties were determined. The results revealed that the specific activity of the Q23L improved remarkably, which increased from 51 u/mg of the wild type to 109 u/mg at pH5.5. Meanwhile, the pH stability of Q23L, decreased evidently, especially from pH3.0 to pH4.0.The pH stability of Q23LG272E in pH3.0 - 4.5 and pH6.5 - 7.0 has been improved compared with Q23L. The specific activity of Q23LG272E basically maintained at the level of Q23L. Analysis of 3-D structure and sequence similarity were used to reveal the presumable factors influencing the enzymatic properties of Q23LG272E, and discussion for the relationship between structure and function of phytase was given.
6-Phytase ; chemistry ; genetics ; metabolism ; Amino Acid Substitution ; Aspergillus fumigatus ; enzymology ; genetics ; Biocatalysis ; Electrophoresis, Polyacrylamide Gel ; Fungal Proteins ; chemistry ; genetics ; metabolism ; Hydrogen-Ion Concentration ; Models, Molecular ; Mutagenesis, Site-Directed ; Mutant Proteins ; genetics ; metabolism ; Mutation ; Pichia ; genetics ; Polymerase Chain Reaction ; Protein Conformation ; Protein Engineering ; methods ; Recombinant Proteins ; metabolism ; Structure-Activity Relationship ; Substrate Specificity

A gene appA encoding a novel phytase was firstly cloned from Hafnia alvei by PCR and sequenced. The gene was consisted of 1335 bp, encoding 444 amino acids. The calculated molecular weight of the mature APPA was about 45.2 kD. The gene appA was expressed in E. coli BL21 (DE3). Recombinant APPA was purified and its enzymatic properties were determined. The optimum pH for the enzyme was 4.5 and the optimum temperature was 60 degrees C. The pH stability of r-APPA is good, the relative phytase activity was above 80% after treated in buffers of pH 2.0-10.0. The specific activity of r-APPA is 356.7 U/mg, and the Km value was 0.49 mmol/L and Vmax of 238 U/mg. The enzyme showed resistance to pepsin and trypsin treatment.
6-Phytase ; biosynthesis ; genetics ; isolation & purification ; Amino Acid Sequence ; Cloning, Molecular ; Escherichia coli ; genetics ; metabolism ; Hafnia ; enzymology ; genetics ; Hydrogen-Ion Concentration ; Molecular Sequence Data ; Recombinant Proteins ; biosynthesis ; genetics ; isolation & purification ; metabolism ; Temperature

A homology modeling of xylanase XYNB from Streptomyces olivaceoviridis A1 was made by Swiss-Model. The hydrophobic Interaction between beta-sheet B1 and B2 in the tertiary structure model of XYNB was compared with other thermophilic xylanase. A T11Y mutation was introduced in XYNB by site-dirrected mutagenesis to improve the thermostability of the enzyme. The XYNB and mutant xylanase (XYNB') expressed in Pichia pastoris were purified and their enzymatic properties were determined. The result revealed that the thermostability of XYNB' was obviously higher than that of XYNB. The optimal temperature of XYNB' for its activity was 60 degrees C, similar to XYNB. But, compare to XYNB, the optimal pH value, the Km value and the specific activity of XYNB' had also been changed. The research results suggested that the aromatic interaction between beta-sheet B1 and B2 in xylanase should increase enzyme thermostability. The mutant xylanase XYNB' is a good material for further research in the relationship between structure and function of xylanase.
Bacterial Proteins ; chemistry ; genetics ; Endo-1,4-beta Xylanases ; chemistry ; genetics ; Enzyme Stability ; Hot Temperature ; Hydrophobic and Hydrophilic Interactions ; Mutagenesis, Site-Directed ; Mutant Proteins ; chemistry ; Pichia ; genetics ; metabolism ; Protein Conformation ; Protein Folding ; Protein Structure, Tertiary ; genetics ; Recombinant Proteins ; biosynthesis ; genetics ; Streptomyces ; enzymology ; genetics ; beta-Glucosidase ; chemistry ; genetics

This study was aimed to explore whether the conditioned culture medium of human umbilical cord-derived mesenchymal stem cells (hUC-MSC) has supportive effects on hematopoiesis in vitro. hUC-MSC were cultured in 75 cm(2) culture flasks at a concentration of 2×10(6) cells per flask. After 48 h, the conditioned culture medium was harvested. CD34(+) cells were isolated with the human cord blood CD34 positive selection kit. The CD34(+) cells were plated in three different culture systems: the culture supernatant from hUC-MSC added into incomplete methylcellulose without recombinant human cytokines as conditioned culture medium; the complete methylcellulose medium with recombinant human cytokines as positive control medium; incomplete methylcellulose adding DMEM/F12 with 10% FBS instead of conditioned culture medium as the negative control medium. After 14 days of culture, colonies containing ≥ 50 cells were scored and types of colonies were classified under inverted microscope. The immunophenotypes of cells which were collected from the colonies were detected by flow cytometry. The results showed that conditioned culture medium of hUC-MSC supported the differentiation of CD34(+) cells into CFU-G (47.67 ± 0.58), CFU-GM (48.67 ± 4.73) and CFU-M (3.00 ± 2.00) in vitro, while the CFU-E, BFU-E or CFU-GEMM were absent. Comparatively, in the positive control medium all kinds of CFU were observed. Interestingly, the percentage of CD45(+)cells of CFU in conditioned culture medium (97.43 ± 2.15)% was more than CD45(+)cells in positive control medium (39.69 ± 0.96)% (P < 0.05). It is concluded that the conditioned culture medium of hUC-MSC has been confirmed to have ability to support hematopoiesis separately in vitro. Besides, it enhances the differentiation of CD34(+) cells into myeloid cells except cells of erythroid lineage.
Antigens, CD34 ; Cell Differentiation ; Cells, Cultured ; Culture Media, Conditioned ; Fetal Blood ; cytology ; Hematopoiesis ; Humans ; Mesenchymal Stromal Cells ; cytology ; Umbilical Cord ; cytology