Modification of nanoscale polymeric adsorbent for the preparative separation and purification of tacrolimus from fermentation broth of Streptomyces tsukubaensis.

Tacrolimus is an important immunosuppressant produced by microbial fermentation. In this study, a modified nanoscale polymeric adsorbent, Ag+-exchanged resin, was prepared and studied for the preparative separation and purification of tacrolimus from fermentation broth of Streptomyces tsukubaensis. The performance and absorption characteristics of the modified nanoscale polymeric adsorbent namely Ag-NPS was evaluated. Notably, Ag-NPS resin displayed the pronounced separation capacities for tacrolimus and its equilibrium adsorption data was well-fitted to the Langmuir isotherm. Moreover, the dynamic adsorption and desorption tests was carried out to obtain the operational parameters for further purification of tacrolimus. Finally, tacrolimus and the two major impurities, ascomycin and dihydrotacrolimus, were separated well in the scale-up purification process. The purity and recovery of tacrolimus was recorded to be 99.12±0.25% and 90.41±2.05%. In conclusion, this method displayed a high potential for separation and purification of tacrolimus and other unsaturated bioactive compounds in high yield from the fermentation broth.

Improvement of tacrolimus production in Streptomyces tsukubaensis by mutagenesis and optimization of fermentation medium using Plackett-Burman design combined with response surface methodology.

OBJECTIVE: This study was conducted to enhance the production of tacrolimus in Streptomyces tsukubaensis by strain mutagenesis and optimization of the fermentation medium. RESULTS: A high tacrolimus producing strain S. tsukubaensis FIM-16-06 was obtained by ultraviolet mutagenesis coupled with atmospheric and room temperature plasma mutagenesis.Then, nine variables were screened using Plackett-Burman experimental design, in which soluble starch, peptone and Tween 80 showed significantly affected tacrolimus production. Further studies were carried out employing central composite design to elucidate the mutual interaction between the variables and to work out optimal fermentation medium composition for tacrolimus production. The optimum fermentation medium was found to contain 61.61 g/L of soluble starch, 20.61 g/L of peptone and 30.79 g/L of Tween 80. In the optimized medium, the production of tacrolimus reached 1293 mg/L in shake-flask culture, and reached 1522 mg/L while the scaled-up fermentation was conducted in a 1000 L fermenter, which was about 3.7 times higher than that in the original medium. CONCLUSIONS: Combining compound mutation with rational medium optimization is an effective approach for improving tacrolimus production, and the optimized fermentation medium could be efficiently used for industrial production.

Two novel amphomycin analogues from Streptomyces canus strain FIM-0916.

Three lipopeptides, the known compound amphomycin, together with two novel compounds named aspartocin D (1) and aspartocin E (2) were obtained from the fermentation broth extraction of Streptomyces canus strain FIM0916 by using various column chromatography techniques. Their structures were elucidated by using spectroscopic methods, mainly by an extensive NMR analysis. It was demonstrated that compounds 1 and 2 are novel analogues of amphomycin, whose structures are similar to aspartocins. Compounds 1 and 2 share the same cyclic decapeptide core of cyclo (Dab2-Pip3-MeAsp4-Asp5-Gly6-Asp7-Gly8-Dab9-Val10-Pro11-), differing only in the side-chain moiety corresponding to Asp1-△3-isohendecenoic acid and Asp1-△3-isododecenoic acid, for aspartocin D and aspartocin E. In bioassays, compounds 1 and 2 exhibited antimicrobial activities against Gram-positive bacteria in the presence of Ca(2+) (1.25 mM); particularly, the activities were enhanced with higher concentrations of calcium.

Effects of zinc and manganese on advanced glycation end products (AGEs) formation and AGEs-mediated endothelial cell dysfunction.

AIMS: The present study investigated the effects of ZnCl2 and MnCl2 supplementations on advanced glycation end products (AGEs) formation and AGEs-mediated endothelial cell dysfunction. MAIN METHODS: Fluorescence detection was used to monitor the Maillard reaction. Inductively coupled plasma optical emission spectroscopy was used to test cellular zinc and manganese levels. Real-time reverse transcription polymerase chain reaction and western blot were used to analyze the expression of endothelial nitric oxide synthase (eNOS), nuclear transcription factor kappa B (NF-κB), and receptor for AGEs (RAGE). Intracellular reactive oxygen species (ROS) and nitric oxide (NO) production, NOS activity were determined by fluorescent probe assay, superoxide dismutase (SOD) activity was determined by water soluble tetrazolium salt assay. KEY FINDINGS: MnCl2 showed excellent inhibitory effect on AGEs formation. Primary cultured bovine aortic endothelial cells (BAECs) were exposed to AGEs for 30 min, followed by trace element treatments. Cell viability and the zinc levels declined due to AGEs exposure, which were improved with the supplementations of ZnCl2 and MnCl2. Furthermore, ZnCl2 supplementation effectively enhanced intracellular NO production, elevated eNOS expression and enzymatic activity, and down-regulated NF-κB activation and RAGE expression. MnCl2 dose-dependently impaired ROS formation, down-regulated NF-κB protein expression and nuclear translocation, as well as restored Mn-SOD enzymatic capability. SIGNIFICANCE: Our findings suggested that trace elements relevant to diabetic, such as zinc and manganese played different roles in the formation of AGEs. Both the elements benefited the AGEs-injured BAECs through different mechanisms.

[Experimental study of saponins from Tribulus terrestris on renal carcinoma cell line].

OBJECTIVE: To investigate the effect of saponins from Tribulus terrestris (STT) on the renal carcinoma cell (786-0) in vitro, and inhibitory mechanisms. METHOD: Effects of SIT on the cytotoxicity, morphological changes of apoptosis, cell cycle and expression of Bcl-2 protein in the 786-0 were tested respectively by MTT method, Wright and acridine orange stain assay, as well as flow cytometry (FCM). RESULT: After the 786-0 was treated by STY, it was shown that: 1) A significant cytotoxic effect was observed by MTT assay; 2) Apoptosis-induced was viewed by Wright and acridine orange stain assay; 3) The distribution of 786-0 on S phase was increased; 4.) The expression of Bcl-2 protein and cyclin D1 was decreased. CONCLUSION: STT can significantly inhibit the growth of 786-0 in vitro, partially, by apoptosis.

[Investigation on inhibitory and apoptosis-inducing effects of saponins from Tribulus terrestris on hepatoma cell line BEL-7402].

OBJECTIVE: To investigate the inhibitory and apoptosis-inducing effects of saponins from Tribulus terrestris (STT) on liver cancer cell line BEL-7402. METHOD: MTT, SRB, Wright staining, acridine orange staining, flow cytometry, and Immunofluorescence microscopy were used to evaluate the effects of STT on BEL-7402 cell line. RESULT: SMT had potent inhibitory effect on BEL-7402 cell line in a concentration-dependent manner. BEL-7402 cells exibited typical morphological alteration of apoptosis when sub-G1 peak could be seen. The expression of Bcl-2 was decreased in STT treated cells as compared with untreated control cells. CONCLUSION: STT exerts its cytotoxic effect on BEL-7402 cells by inducing apoptosis.

[Study on effect of flavonoids from oil-removed seeds of Hippophae rhamnoides on inducing apoptosis of human hepatoma cell].

OBJECTIVE: To investigate the inhibitory and apoptosis-inducing effects of flavonoids from oil-removed seeds of Hippophae rhamnoides (FSH) on liver cancer cell line BEL-7402. METHODS: SRB, Wright staining, electron microscope and flow cytometry are used to study the effects of STT on BEL-7402 cell line. RESULTS: FSH has potent inhibitive effect on BEL-7402 cell line in a concentration-dependent manner. BEL-7402 cells exhibit typical morphological alteration of apoptosis when sub-Gl peak can be seen. CONCLUSION: FSH exerts its inhibitive effect on BEL-7402 cells by inducing apoptosis.