Purification and characterization of an extracellular esterase with organic solvent tolerance from a halotolerant isolate, Salimicrobium sp. LY19.

BACKGROUND: Halotolerant bacteria are excellent sources for selecting novel enzymes. Being intrinsically stable and active under high salinities, enzymes from these prokaryotes have evolved to function optimally under extreme conditions, making them robust biocatalysts with potential applications in harsh industrial processes. RESULTS: A halotolerant strain LY19 showing lipolytic activity was isolated from saline soil of Yuncheng Salt Lake, China. It was identified as belonging to the genus of Salimicrobium by 16S rRNA gene sequence analysis. The extracellular enzyme was purified to homogeneity with molecular mass of 57 kDa by SDS-PAGE. Substrate specificity test revealed that the enzyme preferred short-chain p-nitrophenyl esters and exhibited maximum activity towards p-nitrophenyl butyrate (p-NPB), indicating an esterase activity. The esterase was highly active and stable over broad temperature (20°C-70°C), pH (7.0-10.0) and NaCl concentration (2.5%-25%) ranges, with an optimum at 50°C, pH 7.0 and 5% NaCl. Significant inhibition of the esterase was shown by ethylenediaminetetraacetic acid (EDTA), phenylmethylsulfonyl fluoride (PMSF) and phenylarsine oxide (PAO), which indicated that it was a metalloenzyme with serine and cysteine residues essential for enzyme activity. Moreover, the esterase displayed high activity and stability in the presence of hydrophobic organic solvents with log P(ow) ≥ 0.88 than in the absence of an organic solvent or in the presence of hydrophilic solvents. CONCLUSIONS: Results from the present study indicated the novel extracellular esterase from Salimicrobium sp. LY19 exhibited thermostable, alkali-stable, halotolerant and organic solvent-tolerant properties. These features led us to conclude that the esterase may have considerable potential for industrial applications in organic synthesis reactions.

Autologous cytokine-induced killer cells therapy on the quality of life of patients with breast cancer after adjuvant chemotherapy: a prospective study / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To explore the effect of autologous cytokine-induced killer cells on the quality of life in patient with breast cancer who have already finished the adjuvant chemotherapy.</p><p><b>METHODS</b>One hundred and twenty-eight postoperative patients with breast cancer who underwent anthracycline-based adjuvant chemotherapy were enrolled in this prospective study, and they were randomized into 2 groups, i.e., treatment group, which received the therapy of CIK cells transfusion, and control group, which was given regular follow-up. Meanwhile, patients with positive hormone receptor in the two groups were given endocrine therapy, and the patients with positive axillary lymph nodes were given radiotherapy to the chest wall and regional lymph nodes. The difference of quality of life between the two groups was analyzed according to the EORTC QLQ-BR53 quality of life questionnaire, and the adverse reactions were monitored.</p><p><b>RESULTS</b>As regarding the functional evaluation, the physical function scores of patients of the treatment group were (83.43 ± 14.87) and (88.55 ± 11.62) at 3 and 6 months after the CIK cell therapy, respectively, significantly higher than the baseline value [(74.83 ± 13.82), P < 0.05)]. Global health status/QOL scores were (83.30 ± 19.09) and (89.68 ± 10.81), significantly higher than the baseline value [(77.72 ± 21.05), P < 0.05]. As regarding symptoms, the scores of fatigue, nausea, vomiting and loss of appetite of patients in the treatment group were higher than the baseline value, with significant differences (P < 0.05). The nausea and vomiting scores in the control group at 3 and 6 months of followed-up were (26.67 ± 22.56) and (21.47 ± 21.06), significantly lower than the baseline values [(33.31 ± 27.07), P < 0.05]. The scores of worrying about the future in the patients of treatment group were (47.56 ± 30.84) and (42.33 ± 26.95) after 3 and 6 months, significantly better than the baseline value [(57.41 ± 30.63), P < 0.05]. The systematic therapy side effects scores were (31.95 ± 27.52) and (23.72 ± 22.87), significantly better than the baseline value [(40.56 ± 26.28), P < 0.05]. The scores of arm edema were (45.26 ± 25.42) and (36.61 ± 20.51), significantly milder than the baseline value [(55.11 ± 22.82), P < 0.05]. In the control group, the scores of arm edema were (44.85 ± 28.94) and (38.64 ± 23.68), significantly lower than the baseline values [(53.26 ± 23.84) points, P < 0.05]. Alopecia scores were (29.93 ± 24.72) and (24.18 ± 22.66), significantly lower than the baseline values [(35.92 ± 22.08), P < 0.05]. In the treatment group, the patients' physical function, social function and global health status/QOL, fatigue, insomnia, and worrying about the future rates were significantly higher than that of the control group (P < 0.05 for all). Three patients after CIK reinfusion had transient fever, and 6 cases felt pain in the lower limb, but the symptoms were relieved after symptomatic treatment.</p><p><b>CONCLUSIONS</b>Therapy of autologous CIK cells transfusion can significantly improve the quality of life of breast cancer patients, and the adverse reactions during the treatment can be alleviated by symptomatic treatment.</p>

Production and characterization of a novel extracellular metalloproteinase by a newly isolated moderate halophile, Halobacillus sp. LY6.

A moderately halophilic bacterium LY6 with high proteolytic activity was isolated. Biochemical and physiological characterization, along with 16S rDNA sequence analysis placed the isolate in the genus Halobacillus. The salinity of the culture medium strongly influenced the proteinase production of LY6. Maximum enzyme production was observed in the medium containing 5% Na(2)SO(4) or 10% NaCl. Proteinase production was synchronized with bacterial growth and reached a maximum level during the mid-stationary phase. Enzyme purification was carried out by a simple approach including a combination of ammonium sulfate precipitation and Sephacryl S-100 gel filtration chromatography. SDS-PAGE and gelatin zymography analysis revealed it was a monomer with high molecular weight of 69 kDa. Optimal proteinase activity was obtained at pH 10.0, 40°C, and 10% NaCl. It was high active over broad temperature (30-80°C), pH (6.0-12.0), and NaCl concentration (0-25%) ranges, indicating its thermostable, alkali-stable, and halotolerant nature. Moreover, the enzyme activity was markedly enhanced by Ca(2+) and Cu(2+), but strongly inhibited by EDTA, PAO, and DEPC, indicating that it probably was a metalloproteinase with cysteine and histidine residues located in its active site.

The function of ERK on Fas-mediated apoptotic signaling pathway of human gastric carcinoma cells / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To analyze the expression and functions of ERK (extracellular regulated kinase) in Fas-mediated apoptosis in gastric carcinoma cell line SGC-7901 and to elucidate the potential significance of this signaling pathway in tumor progression.</p><p><b>METHODS</b>Radioisotope labeling and Western blotting with special anti-ERK antibody were used to check ERK activity in SGC-7901 cell line after anti-Fas antibody treatment. Apoptosis induced by several treatment factors was evaluated by FACS can flow cytometer.</p><p><b>RESULTS</b>ERK activity increased and reached the peak at 30 min after treatment with anti-Fas antibody and decreased in PD98059 pretreated group. The number of sub-G(1) cell was 30.5% +/- 2.6% in PD98059 pretreated group, which was higher than anti-Fas treatment group and control group, respectively.</p><p><b>CONCLUSION</b>In gastric cancer cell line SGC-7901, Fas-induced ERK activation may suppress Fas-mediated apoptosis. Inhibition of ERK may enhance the sensitivity of SGC-7901 cells to Fas-mediated apoptosis. Fas-induced ERK activation may confer gastric cancer cells ability to escape the immune surveillance.</p>