Direct proteomic mapping of Streptomyces avermitilis wild and industrial strain and insights into avermectin production.

An industrial mutant of Streptomyces avermitilis produced avermectin at a high level in industrial complex culture medium. However, almost no avermectin was detected in the cultures of tryptone soya broth (TSB). Its wild-type strain could not synthesize avermectin. To elucidate the regulatory mechanism about avermectin production, proteomic analysis of S. avermitilis was carried out. Results showed that during avermectin biosynthesis, fatty acid metabolism and TCA cycle were repressed. Partial enrichment of glycolytic pathway indicated the critical role of glucose catabolism during avermectin biosynthesis. Some enriched enzymes in amino acid metabolic pathways (glnA, leuC) confirmed the leucine as the possible precursor of avermectin. Highly expressed stress or stress-related proteins indicated a global regulation mechanism at the onset of avermectin production. And highly expressed morphology control proteins revealed an association between hyphal morphology and avermectin production. Further, this study proofed strengthened capability to utilize carbon and nitrogen source in the industrial strain. Some stress or stress-related proteins (eshA, clpC, dnaK and grpE) expressed at low level in the industrial strain cultivated in non-production medium (lower than that in the wild-type strain), but these highly expressed at the onset of avermectin production. More sensible response to environmental stress may be responsible for it.

Does urothelial cancer of bladder behave differently in young patients?

BACKGROUND: Bladder urothelial cancer has been diagnosed at an increasing rate among young adults in China while the clinical outcomes remain highly controversial. To optimize the management of young patients with bladder cancer, we examined whether bladder urothelial cancer in young patients behaved differently from that in the elder patients. METHODS: From 1994 to 2008, a database of bladder urothelial cancer patients at a major tertiary medical center was retrospectively reviewed. The clinical and pathological parameters of patients who were less than 40 years of age and a series of patients older than 40 years of age as the control group during the same period were compared. A survival analysis was performed using the Kaplan-Meier method and log-rank test, and Cox regression was performed to identify clinical parameters that affected the clinic outcomes. RESULTS: Young bladder cancer patients had a lower male-to-female ratio and were less likely to have advanced stages and high-grade cancers at the initial diagnosis. Tumors in young bladder cancer patients tended to be less multifocal at diagnosis. In addition, young patients had a lower recurrence rate and longer recurrence interval than older patients. The Kaplan-Meier curve and Log-rank test showed that young patients had significantly better cancer specific survival than old patients. The univariate and multivariate Cox regression analysis revealed that tumor grade is the sole predictor for tumor recurrence in young patients. CONCLUSIONS: Young patients with bladder cancer have favorable pathological features and clinical outcomes than older patients. These findings argue for more conservative management approaches for young patients with bladder cancer.

[Effect of polygona-polysaccharids on atheromatous plaque: experiment with rabbits].

OBJECTIVE: To study the effect of polygona-polysaccharids on the elimination of atheromatous plaque. METHODS: Thirty adult New Zealand rabbits were fed with high-fat and cholesterol forage for 8 weeks to establish hyperlipidemia animal models and then randomly divided into 3 equal groups: model group, simvastatin group receiving simvastatin orally, and polygona-polysaccharids group receiving polygona-polysaccharids orally. Ten rabbits were fed with normal food as control forage. At weeks 0, 2, and 8 the levels of total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), and lipoprotein (a) [Lp (a)] were determined with enzyme method. At the end of the week 8, all rabbits were killed to observe the elimination of aorta atheromatous plaque by microscope. RESULTS: Before the experiment, there were no significant differences in the levels of serum lipids among all groups. At the end of week 2 (before treatment), the levels of serum TC of the model group, simvastatin group, and polygona-polysaccharids group were (10.2 +/- 1.6) mmol/L, (11 +/- 1.8) mmol/L, and (11.2 +/- 1.9) mmol/L respectively, the LDL-C levels of the 3 groups were (9.85 +/- 1.65) mmol/L, (9.80 +/- 1.54) mmol/L, and (10.08 +/- 1.88) mmol/L respectively, the Lp (a) levels of the 3 groups were (656 +/- 106) mmol/L, (700 +/- 151) mmol/L, and (666 +/- 111) mmol/L respectively, all significantly higher than that of the control group [(1.3 +/- 0.3) mmol/L, (0.55 +/- 0.15) mmol/L, and (106 +/- 15) mg/L respectively, all P < 0.01]. At the end of week 8 (after treatment), the levels of serum TC, LDL-C, and Lp (a) of the polygona-polysaccharids group were (6.0 +/- 2.0) mmol/L, (4.25 +/- 1.35) mmol/L, and (55 +/- 14) mg/L respectively, all significantly lower than that at the end of week 2 [(11.2 +/- 1.9) mmol/L, (10.08 +/- 1.88) mmol/L, and (666 +/- 111) mg/L respectively, all P < 0.01]. The aorta atheromatous plaques in the polygona-polysaccharids group were basically eliminated compared with that in the model group. CONCLUSION: Polygona-polysaccharids (1.6 ml.kg(-1).d(-1)) has the effect of eliminating aorta atheromatous plaques.

[Effects of temperature on the kinetics and level of energy charge and oxidation-reduction state in pyruvate biosynthesis].

Temperature plays an important role in pyruvate biosynthesis by Torulopsis glabrata 620. The effects of temperature on the substrate consumption, cell growth, pyruvate biosynthesis and level of energy charge and oxidation-reduction state have been investigated. During the constant temperature fermentation, higher temperature can enhance the rate of glucose consumption, cell growth and pyruvate production. However, it also leads to higher energy charge in the prophase of fermentation, too much consumption of glucose by cell and deficient throughput of pyruvate in the anaphase of fermentation, which brings on decrease of pyruvate yield. Oppositely, maintaining lower temperature during the fermentation can offer constant production capacity of pyruvate in the anaphase of fermentation. But the disadvantages are lower cell growth and higher level of NADH/NAD+ in vivo during the anaphase of fermentation, which leads to lower productivity inevitably. Disaccords above-mentioned indicate that the higher production, higher yield and higher productivity cannot be achieved at one time during a constant temperature fermentation.

[LC-ESI/MS identification and reduction of impurities in spiramycin fermentation].

There are several impurities in the spiramycin fermentation broth which leads to a lower yield and lower quality of the product. Four impurities in spiramycin broth have been simultaneously separated and identified by LC-ESI/MS. The generation of these impurities was attributed to the fluctuation of glucosylation in spiramycin biosynthesis. Nitrogen sources, ammonium in particular, were found to play an important role at the glucosylation. Aided with the information of LC-ESI/MS analysis and subsequent optimization of the culture medium, better culture medium of shake flask was designed, which leads to reduction of impurities by 22% - 88%.

[Determination of organic acids in fermentation broth of spiramycin by high performance liquid chromatography].

A method for determining organic acids in spiramycin fermentation broth by high performance liquid chromatography is described. The operating conditions were Zorbax 300-SB C18 column (5 microns, 4.6 mm i.d. x 15 cm) at 35 degrees C, 0.01 mol/L phosphoric acid buffer solution (pH 2.32) and methanol as mobile phase at a flow rate of 0.6 mL/min and UV detection at 210 nm. The relative standard deviations were 0.33%-0.10% and the recoveries were 99.95%-100.08%. It's a simple, rapid and accurate method.