Advanced Materials Research Vols. 343-344

Abstract: In order to probe into orderliness changes of Glutathione S-Transferase (GST) of chloroplast of Puccinellia tenuiflora seedlings under Na₂CO₃ stress and its function in resistance to Na₂CO₃ stress, relative electric conductance, GST activity and the O₂^-.produce rate of the chloroplast, and the osmotic potential of leaves, and the osmotic potential of culture solution of P. tenuiflora seedlings under different Na₂CO₃ stress were concerned. The result shows that in the Na₂CO₃ stress range of 0～0.4%, along with the increase of its intensity under different Na₂CO₃ stress intensity, GST activity of the chloroplast of seedling leaves of P. tenuiflora is strengthened and GST activity is rapidly weakened with the increase of the intensity of Na₂CO₃ stress more than 0.4%. The change of GST activity of the chloroplast along with the osmotic potential of culture solution and seedling leaves, relative electric conductance of the seedling leaves as well as the O₂^-.produce rate have the similar change tendency. There is significant nonlinear relationship among GST activity of chloroplast, osmotic potential of the seedling leaves and Na₂CO₃ concentration of culture solution, and among GST activity of chloroplast, O₂^-.produce rate and osmotic potential of seedling leaves, and among GST activity of chloroplast, osmotic potential of culture solution and that of seedling leaves, and among GST activity, the O₂^-.produce rate of chloroplast and relative electric conductance of the seedling leaves. These indicate that GST of chloroplast plays an important role in the process of seedlings of P. tenuiflora in resistance to the low intensity of Na₂CO₃ stress.

Abstract: Due to the degeneracy of genetic code, most amino acids are coded by more than one codon (synonymous codons). The synonymous codons are not used at equal frequencies both within and between organisms. Of the total 33 herpesvirus gB genes, approximately 9.1% of the total gB genes had low codon bias (ENC<35), 72.7% of the gB genes had high ENC values (ENC>50), indicating that these gB genes had random codon usage in herpesviruses. There might be no direct correlation between the codon usage bias and the host, which indicates that the tRNA abundance of the host was not the main factor influencing the codon usage bias. A plot of ENC vs. GC3 indicates that mutational bias may be a more important factor than tRNA abundance in determining codon usage bias of herpesvirus gB genes. Pearson correlation coefficients between the ENC value and corresponding GC%, cumulative GC% in 2nd (GC2%) and 3rd codon position (GC3%) of each herpesvirus gB gene were -0.621 (p<0.01), -0.656 (p<0.01) and -0.712 (p<0.01), respectively, which implies that significant correlations existed between them. But no significant correlations existed between ENC and cumulative GC% in 1st codon position of each herpesviral gB gene. Furthermore, significant correlations also existed between GC% and GC3% of 33 herpesvirus gB genes (r=0.856, p<0.01). So it seems that, GC content, and particularly GC content at the 3rd base position, contributing greatly to the effective number of codons, indicating that the mutational bias dominates over translational selection. Further analysis on the relationship between gene length and ENC of 33 herpesvirus gB genes demonstrated that the two factors were not correlated. Significant correlations were found between the gene expression levels assessed by CAI value and ENC (r = -0.424, p<0.05) and GC3 values (r = 0.644, p<0.01).

Abstract: In this report, we conduct study on codon composition and codon usage of DPV glycoprotein B (gB) gene, its homologs constitute the most highly conserved family of herpesvirus glycoproteins and are present in members of each herpesvirus subfamily. Our results show that sixty-one codons (excluding the termination codons) in the polypeptide, a high level of diversity in codon usage bias existed for coding the Ala, Gly, Leu, Pro, Arg, Ser, Thr and Val amino acids. Sixteen codons (each for a amino acid), including GCA (Ala), GAT (Asp), GAA (Glu), GGA (Gly), CAT (His), ATA (Ile), AAA (Lys), CTA (Leu), AAT (Asn), CCA (Pro), CAA (Gln), AGA (Arg), TCT (Ser), ACT (Thr), GTA (Val) and TAT (Tyr) were determined as the translationally optimal codons. The codon preferences of DPV gB gene were compared with those of E. coli, yeast, and H. sapiens, we can speculate that the DPV gB gene may be more efficiently expressed in the E. coli system. In summary, knowledge of codon usage of herpesvirus gB genes provides insights into molecular and species evolution, and also plays important role in furthering some biotechnological applications. These would be fruitful areas for further study.

Abstract: This research aimed to study the effects of 30 kinds of Chinese herbs on fungi in food. 30 kinds of Chinese herbs and 6 common fungi in food were used as experiment material. The effects of water, ethanol absolute and petroleum ether extracts on fungi were studied by filter paper method. The results showed that water extracts of Coptis chinensis. and Magnolia officinalis Rehd.et Wils., the ethanol extracts of Syzygium aromaticum Thunb., Coptis chinensis, Cinnamomum cassia Presl and Cassia Bark, the petroleum ether extracts of Syzygium aromaticum Thunb. and Cassia Bark had strong antimicrobial ability. The study can provide the scientific basis for exploring natural food preservatives.

Abstract: Phospholipase D-mediated transphosphatidylation to phosphatidylserine from phosphatidylcholine was successfully performed using subcritical 1,1,1, 2-tetrafluoroethane (R134a) as reaction medium. Phospholipase D from Stretomyces sp was found to be active in subcritical R134a at 30-50°C and 2-8MPa; Higher velocity and conversion were observed with respect to those attained in conventional organic solvents. A maximum conversion of 84.88% was attained at 6 MPa, 40°C, after 240 minutes with 9.6 units phospholipase D.

Abstract: The different concentrations C-phycocyanin (C-PC), Allophycocyanin (APC) or R-phycoerythrin(R-PE) solution can reconstitute with thylakoid to synthesize different donor-acceptor complexes. The energy transfer efficiencies of those complexes are studied, where C-PC, APC and R-PE are donor, the thylakoid are acceptor. The results show excitation energy can be transfered to thylakoid from C-PC or APC. However, the energy transfer process of R-PE to thylakoid membrane does not happen. The energy transfer process of the APC to thylakoid membrane shows the highest efficiency. Those results also indicate that the linkage between phycobiliproteins and thylakoid does not have specificity. It can be concluded that the energy transfer efficiencies not only strongly depend on the relative positions of donor and acceptor but also on spectral matching relation between phycobiliproteins and Chla molecules in thylakoid membrane.

Abstract: Hirudin is the most potent natural inhibitor of thrombin and a powerful anticoagulant. Large-scale production of recombinant hirudin is desirable for therapy. In this study, the gene encoding hirudin variant III was redesigned and synthesized by using Bacillus subtilis preferred codons, and the recombinant hirudin variant III (rHV3) was overexpressed in B. subtilis DB403 with strong anticoagulation activity for the first time. The hirudin activity from the supernatant of culture with optimized expression conditions could reach 210 ATU/ml. The protein in culture supernatant was precipitated by trichloroacetic acid, then desalted by ultrafiltration and purified by anion exchange chromatography. Strong anion Q F.F. performed better than weak anion DEAE F.F. The proper pH and conductivity was determined at pH 8 and 6 ms/cm, respectively. The maximum applied sample was 240 ATU/ml to medium of strong anion Q F.F. This optimized procedure was employed in strong anion exchange HiPrep 16/10Q with the 90% recovery rate and 70.2% purity. After gel filtration, the purity of rHV3 checked by HPLC could reach 95.1%, and the recovery rate was 93% for this step. The purified recombinant rHV3 showed a single band in SDS-PAGE. The rHV3 was stable at 100 °C and acidity condition, but was unstable under the condition of both heating and alkalinity. In conclusion, theses studies suggests that B.subtilis might be useful for the production of biologically active medicine peptides in secretion facilitating purification procedures, and that this isolation method was suitable for scale-up purification process at a low cost.

Abstract: This work developed a simple and sensitive method for the simultaneous determination of erythromycin (Ery) and haloperidol (Hal) in human urine by capillary electrophoresis with eletrochemiluminescence detection. Under optimized conditions, such as detection potential at 1.25 V, electrokinetic injection at 10 kV for 6 s, separation voltage at 10 kV, 15 mmol/L separation buffer with pH 6.5, 5 mmol/L Ru(bpy)₃²⁺ and 50 mmol/L phosphate buffer with pH 8.0 in the ECL cell, the linear concentration ranges for Ery and Hal were from 0.005 to 0.2 μg/mL and from 0.15 to 6.0 μg/mL, respectively. The detection limits (3σ) for Ery and Hal were 0.002 and 0.06 μg/mL, respectively. When the method was applied to determine Ery and Hal in human urine, the recoveries were 96.5% and 95.1% on an average, respectively.

Abstract: The analytical method for calcium species in human blood was studied using ultrasonic-assisted dialysis coupled with capillary electrophoreisi (CE) inductively coupled plasma optical emission spectrometry (ICP-OES). The optimal ultrasonic dialysis conditions were 72 W power, 60 min extraction time and 70 μL volume of blood sample. Ultrasonic-assisted dialysis improves significantly the dialysis efficiecy by comparing with balance dialysis. The optimized conditions of separation and detection (a 120 cm length×100 μm i.d. fused-silica capillary, 20 kV separation voltage, 30 mmol/L Tris-HCl with pH7.4 buffer solution) for calcium species were achieved by CE-ICP-OES. The forms of calcium in the dialysate of human blood have five different species. The concentration of free Ca²⁺ in the dialysate was 0.7 mg/L. The hyphenated technique is simple and convenience, which is fit for the separation and analysis of metal-containing biological samples.

Abstract: Organic solvent-tolerant lipases have shown new potential application in biotechnological fields. A novel strain which produced an organic solvent-tolerant lipase was isolated from soils in different areas of China. Based on the morphological, physiological and biochemical features and 16S rDNA sequence of the strain, it was identified as Pseudomonas aeruginosa CS-2. The crude lipase had an improved stability in the presence of acetonitrile and it exhibited stability in presence of benzene, chloroform, n-Hexane, petroleum ether and isooctane. The optimized composition of culture medium was as follows: olive oil 1%, peptone 4%, K₂HPO₄ 0.5%, MgSO₄·7H₂O 0.1%, gum arabic 0.04%. The optimum condition for lipase production was on the following: temperature 37°C, initial pH 7.5, rotary shaking speed 200 rev/min, culture time 48 h.