Construction of engineered Streptococcus zooepidemicus for the production of hyaluronic acid ligosaccharide / 生物工程学报

Hyaluronic acid (HA) is widely used in many fields, such as medicine, cosmetics and food. The bioactivity of HA depends on its molecular weight (Mw). Owing to the important physiological activities and special physiological functions, HA oligosaccharides have important application prospects in medicine fields. Streptococcus zooepidemicus has wide applications in commercial production of HA, due to its short fermentation cycle and strong production intensity. In order to efficiently synthesize HA oligosaccharides and solve the dissolved oxygen in the fermentation process, in this study, we overexpressed HA synthase (HasA) and introduced and optimized the leech hyaluronidase LHAase in Streptococcus zooepidemicus WSH-24. As a result, HA oligosaccharides were efficiently produced with improved dissolved oxygen. After 24 h, HA oligosaccharides production intensity reached to 294.2 mg/(L·h), and the concentration accumulated to 0.97 g/L in flask cultures, which was 1.82 times of the wild strain. Impressively, HA oligosaccharides were increased to 7.06 g/L in 3 L fermentor. The constructed Streptococcus zooepidemicus strain for producing HA oligosaccharides would have broad application prospects.

The expression and clinical significance of hyaluronan synthase in nasal polyps / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To study the expression of hyaluronan synthasel-3 (HAS1-3) in nasal polyps, and discuss their clinical significance.@*METHOD@#The expression of HA, HAS1, HAS2 and HAS3 in nasal polyps group (25 cases) and inferior turbinate group (15 cases) was detected by immunohistochemistry and semi-quantitative RT-PCR.@*RESULT@#Compared with the control, the expression of HA, HAS1 and HAS3 was higher in nasal polyps (P0. 05).@*CONCLUSION@#The increase of HASI and HAS3 expression may be the main cause of the excessive deposition of HA in nasal polyps, which may play an important role in the pathogenic process of nasal polyps, and become a potential target for therapy of nasal polyps.

Effects of two UDP-glucose dehydrogenases on hyaluronic acid biotransformation / 生物工程学报

We amplified genes encoding UDP-glucose dehydrogenase, ecohasB from Escherichia coli and spyhasB from Streptococcus pyogenes. Both ecohasB and spyhasB were inserted into T7 expression vector pRX2 to construct recombinant plasmids pRXEB and pRXSB, and to express in E. coli BL21(DE3). After nickel column purification of UDP-glucose dehydrogenases, the enzymes were characterized. The optimum reaction condition of spyHasB was at 30 °C and pH 10. The specific activity reached 12.2 U/mg under optimum condition. The optimum reaction condition of ecoHasB was at 30 °C and pH 9. Its specific activity reached 5.55 U/mg under optimum condition. The pmuhasA gene encoding hyaluronic acid synthase was amplified from Pasteurella multocida and ligated with ecohasB and spyhasB to construct the coexpression vectors pBPAEB and pBPASB, respectively. The co-expression vectors were transformed into E. coli BW25113. Hyaluronic acid (HA) was produced by biotransformation and the conditions were optimized. When recombinant strains were used to produce hyaluronic acid, the higher the activity of UDP-glucose dehydrogenase was, the better its stability was, and the higher the HA production could reach. Under the optimal conditions, the yields of HA produced by pBPAEB/BW25113 and pBPASB/BW25113 in shake flasks were 1.52 and 1.70 g/L, respectively, and the production increased more than 2-3 folds as previously reported.

Differential expression of hyaluronic acid synthase family in human bladder transitional cell carcinoma and its clinical significance / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the differential expression of the hyaluronic acid synthase (HAS) family in human bladder transitional cell carcinoma (BTCC) and its potential clinical significance.</p><p><b>METHODS</b>The relative quantitative detection of the expression of HAS isoforms (HASs) was performed in 78 human BTCC tissues (mRNA & protein) and 12 normal human bladder mucosa (protein) by real-time RT-PCR and Western blot, and the results were statistically analyzed according to the clinical data.</p><p><b>RESULTS</b>All the BTCC tissues expressed three HAS isoform mRNA and protein, but to a different extent, as for mRNA, HAS3 > HAS2 > HAS1 (P < 0.001), with a significant difference in HAS1/HAS2, HAS1/HAS3 and HAS2/HAS3 (P = 0.003, < 0.001, 0.006, respectively). Among the proteins, the HAS2 expression was the highest, with a significant difference in HAS1/HAS2, and HAS2/HAS3 (P = 0.004, 0.001, respectively), but not in HAS1/HAS3. The elevation of HAS1 mRNA and protein expression was significantly related with the tumor malignancy, tumor initial onset/recurrence, T1/T2 and T1/T3-4 stags, and tumor grading (P = 0.02, < 0.001, 0.038, < 0.001; 0.025, 0.031, 0.023, 0.002; respectively). The HAS2 mRNA expression was significantly related with tumor size (diameter ≤ 3.0 cm/> 3.0 cm), tumor number (single or multiple), tumor initial onset/recurrence, T-staging, and histopathological differentiation (low grade/high grade) (P = 0.012, 0.004, < 0.001, < 0.001, < 0.001, respectively), but its protein expression was not significantly different in all subgroups except with the tumor size (mass diameter > 3.0 cm/≤ 3.0 cm). However, HAS3 mRNA and protein expression had no significant difference among all the subgroups. In normal human bladder mucosa, no HAS expressions were detected.</p><p><b>CONCLUSIONS</b>The abnormally high expression of the HASs further indicate the reliability of hyaluronan as a urinary marker for human BTCC. Compared with HAS1 and HAS3, HAS2 as a marker may have more usefulness in studies on human BTCC carcinogenesis or development. The high expression of HAS1 protein seems to play a more important role in the BTCC tumorigenesis, and may indicate a poor prognosis of the BTCC patients.</p>

Folic acid antagonist methotrexate causes the development malformation of heart and down-regulates the BMP2b and HAS2 expressions in zebrafish / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the effect of methotrexate (MTX), a folic acid antagonist which can lead to folic acid deficient, on the cardiac development and on the expressions of BMP2b and HAS2 in zebrafish.</p><p><b>METHODS</b>The zebrafish embryos at 6-48 hrs post fertilization (hpf) were treated with various concentrations of MTX (0.5 x 10(-3), 1.0 x 10(-3) and 2.0 x 10(-3) M). At 48 hpf, the percentage of cardiac malformation and heart rate were recorded. The zebrafish embryos at 6-10 hpf treated with 1.5 x 10(-3) M MTX were used as the MTX treatment group. At 24 and 48 hpf the cardiac morphology was observed under a microscope. The expressions of BMP2b and HAS2 in zebrafish were detected by in situ antisense RNA hybridization and real-time PCR.</p><p><b>RESULTS</b>6-12 hpf, the early embryonic developmental stage, was a sensitive period that MTX affected cardiac formation of zebrafish. The retardant cardiac development and the evidently abnormal cardiac morphology was found in the MTX treatment group. The results of in situ antisense RNA hybridization showed that the expressions of BMP2b and HAS2 in the zebrafish heart were reduced in the MTX treatment group at 36 and 48 hpf. The real-time PCR results demonstrated that the BMP2b expression decreased at 12, 24, 36 and 48 hpf, and that the HAS2 expression decreased at 24, 36 and 48 hpf in the treatment group compared with the control group without MTX treatment.</p><p><b>CONCLUSIONS</b>The inhibition of folic acid function may affect cardiac development of early embryos, resulting in a retardant development and a morphological abnormality of the heart in zebrafish, possibly by down-regulating the expressions of BMP2b and HAS2.</p>

Cumulus-specific genes are transcriptionally silent following somatic cell nuclear transfer in a mouse model / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

This study investigated whether four cumulus-specific genes: follicular stimulating hormone receptor (FSHr), hyaluronan synthase 2 (Has2), prostaglandin synthase 2 (Ptgs2) and steroidogenic acute regulator protein (Star), were correctly reprogrammed to be transcriptionally silent following somatic cell nuclear transfer (SCNT) in a murine model. Cumulus cells of C57xCBA F1 female mouse were injected into enucleated oocytes, followed by activation in 10 micromol/L strontium chloride for 5 h and subsequent in vitro culture up to the blastocyst stage. Expression of cumulus-specific genes in SCNT-derived embryos at 2-cell, 4-cell and day 4.5 blastocyst stages was compared with corresponding in vivo fertilized embryos by real-time PCR. It was demonstrated that immediately after the first cell cycle, SCNT-derived 2-cell stage embryos did not express all four cumulus-specific genes, which continually remained silent at the 4-cell and blastocyst stages. It is therefore concluded that all four cumulus-specific genes were correctly reprogrammed to be silent following nuclear transfer with cumulus donor cells in the mouse model. This would imply that the poor preimplantation developmental competence of SCNT embryos derived from cumulus cells is due to incomplete reprogramming of other embryonic genes, rather than cumulus-specific genes.