ABSTRACT
Aims@#Hyaluronic acid (HA) is a high molecular weight polymer and a major component of mucoid capsule in bacteria and extracellular matrix (ECM) of vertebrate tissue. Due to its unique characteristics, HA is used extensively in medical and cosmetic field. However, because of the exotoxins production from animal tissues extraction and Streptococcus zooepidemicus, HA production by recombinant microorganisms has gained interest. The present study was aimed at cloning of hasA gene in Escherichia coli and optimization of the medium components for HA production. @*Methodology and results@#A fragment of an approximate size of 1.5 kb that encodes the hyaluronan synthase (hasA) gene from S. zooepidemicus ATCC 39920 was amplified by PCR using hasA-specific primers. The hasA gene was ligated into the bacterial expression vector pLbADH and transformed into the expression host, Escherichia coli BL21 strain. Then, genetically engineered E. coli strain BL21 was used for the production of HA by fermentation using different glucose concentration (10-50 g/L) and different IPTG concentration (0.1, 0.5 and 1.0 mM) in shake flask culture. Amongst varying glucose concentrations, results showed that 50 g/L glucose with nutrient rich media containing nitrogen source was able to produce the highest HA concentration (0.115 ± 0.002 g/L). With addition of 1.0 mM IPTG, HA production reached a peak 0.532 ± 0.026 g/L which is around fivefold higher compared to without IPTG. @*Conclusion, significance and impact of study@#The hasA gene was cloned from S. zooepidemicus and successfully expressed in recombinant E. coli BL21 cells. This low molecular weight HA is gaining more importance in medical and cosmetic application due to possess pronounced free radical scavenging and antioxidant activities.
ABSTRACT
Objective To investigate the effects of soluble CD40L (sCD40L) on proliferation of orbital fibroblasts (OFs) and the expression of three types of hyaluronan synthase (HAS) in vitro, so as to explore the role of sCD40L in the pathogenesis of thyroid-associated ophthalmopathy (TAO). Methods OFs obtained from 5 patients with TAO and 3 normal controls were primarily culutred. The effect of different concentrations of sCD40L (6.25,12.5,25,50,100 and 200 ng/mL) on proliferation of OFs of different sources were examined by MTS after 48 h exposure. OFs were also cultured with different concentrations of sCD40L (12.5, 25, 50 and 100 ng/mL) for 3,6,12 and 24 h, and then the expression levels of HAS 1-3 mRNA were determined by real-time RT-PCR. Results Treatment with sCD40L at concentrations higher than 25 ng/mL for 48 h obviously promoted the proliferation of OFs in patients with TAO (P<0.05). In contrast, treatment with sCD40L only at concentrations higher than 50 ng/mL for 48 h could promote proliferation of OFs from normal control, and the effect was comparatively weak. HAS3 mRNA expression of OFs in TAO patients was increased after exposed to sCD40L (P<0.05), and the increase was in a concentration- and time-dependent manner. Conclusion sCD40L can promote the proliferation of OFs and expression of HAS3 mRNA in patients with TAO, which implies that sCD40L plays an important role in the pathogenesis of TAO.
ABSTRACT
Objective To study the difference between the mRNA expressions of hyaluronan synthase in the epithelial cells of endolymphatic sac and renal tubules with the oligonucleotide probe. Methods The oligonucleotide probe of hyaluronan synthase was designed and synthesized, the mRNA expressions of hyaluronan synthase in the epithelial cells of endolymphatic sac and renal tubules were detected with hybridization in situ. Results mRNA of hyaluronan synthases were strongly expressed in some epithelial cells of endolymphatic sac and renal tubules. Conclusion It is confirmed that a dual regulatory system for hyaluronan /hyaluronidase exists in the epithelial cells of endolymphatic sac and renal tubules at the level of molecular biology.