Improving the biotransformation of phytosterols to 9α-hydroxy-4-androstene-3,17-dione by deleting embC associated with the assembly of cell envelope in Mycobacterium neoaurum.

The conversion of low value-added phytosterols into 9α-hydroxy-4-androstene-3,17-dione (9-OHAD) by mycobacteria is an important step in the steroid pharmaceutical industry. However, the highly dense cell envelope with extremely low permeability largely affects the overall transformation efficiency. Here, we preliminarily located the key gene embC required for the synthesis of lipoarabinomannan from lipomannan in Mycobacterium neoaurum. The genetic manipulation of embC indicated that it might be the only functional enzyme catalyzing the above synthesis process. The deficiency of lipoarabinomannan led to a significantly increased cell permeability, which in turn caused the enhanced uptake capacity of cells. The sterol substrate conversion efficiency of mycobacterial cells was increased by about 52.4 % after 72-h conversion. Ultimately, the absence of embC increased the productivity from 0.0927 g/L/h to 0.1031 g/L/h, as confirmed by a resting cell system. This study verified the feasibility of improving the efficiency of the microbial conversion system through the cell envelope engineering strategy.

A simple liquid chromatography tandem mass spectrometric method for fast detection of hydrogen sulfide based on thiolysis of 7-nitro-2, 1, 3-benzoxadiazole ether.

The long identified toxic gas, hydrogen sulfide (H2S), which has also been confirmed as the third gaseous signaling molecule following NO and CO, plays important roles in various physiological and pathological process. The current most established quantification method for H2S is HPLC method coupled with fluorescence detection after derivatization with a costly fluorescent reagent, Monobromobimane (MBB). However, The MBB method is characterized by strict reaction condition, long reaction time, tedious operation, and inconsistent reported results. In this study, based on the thiolysis reaction of 7-nitro-2, 1, 3-benzoxadiazole (NBD) ether, the commonly used chromatographic modifier 4-chloro-7-nitro-2,1,3- benzoxadiazole (NBDCl) and four probes (NBDOMe, NBDOEt, NBDOTFE and NBDOCMR) synthesized from NBDCl were tested as alternatives for fast quantification of H2S by LC-MS/MS. The reaction product between NBD ethers/NBDCl and H2S showed special pink color visible to the naked eye and was easy to synthesize and separate in lab; it also showed good retention on common chromatographic columns and high instrument response; therefore it is a good determinand. After establishment of LC-MS/MS methods for all the related compounds, the reaction conditions were optimized for all the probes with H2S. Then the stability, selectivity, reaction rate, sensitivity and quantitative linear relationship between the reaction product and H2S concentration were studied for each probe. Finally, NBDOEt was selected for LC-MS/MS detection of H2S. In comparision with the MBB method, the established NBDOEt method showed matched sensitivity and linearity, better selectivity, and higher repeatability; and had the advantages of easy operation, simple reaction condition, and cheap raw materials. The method was successfully validated and applied to determination of Na2S content in Na2S∙9H2O bulk drug and injection. In conclusion, NBDOEt is a promising option for quantification of H2S in abiotic matrix.

New azaphilones, phomopsones A-C with biological activities from an endophytic fungus Phomopsis sp. CGMCC No.5416.

Three undescribed azaphilones, phomopsones A-C (1-3) and two known azaphilones (4-5) were isolated from the culture of endophytic fungus Phomopsis sp. CGMCC No.5416 from the stems of Achyranthes bidentata. Their structures were determined by spectroscopic analysis (HRESIMS, 1D and 2D NMR), and the absolute configurations were determined by CD spectroscopy. Compounds 2 and 3 showed significant inhibitory activities against HIV-1 with against HIV-1 with IC50 values of 7.6 and 0.5 µmol/L, respectively. Compounds 2 and 3 also displayed moderate cytotoxicity with CC50 values of 3.2-303 µmol/L against A549, MDA-MB-231 and PANC-1 cell lines. Moreover, compound 3 can induce the early apoptosis of PANC-1 cancer cells with the apoptosis rate of 28.54%.

Influence of heat treatments upon the mechanical properties and in vitro bioactivity of ZrO2-toughened MgO-CaO-SiO2-P2O5-CaF2 glass-ceramics.

Zirconia-toughened MgO-CaO-SiO2-P2O5-CaF2 glass-ceramics are prepared using sintering techniques, and a series of heat treatment procedures are designed to obtain a glass-ceramic with improved properties. The crystallization behavior, phase composition, and morphology of the glass-ceramics are characterized. The bending strength, elastic modulus, fracture toughness, and microhardness of the glass-ceramics are investigated, and the effect mechanism of heat treatments upon the mechanical properties is discussed. The bioactivity of glass-ceramics is then evaluated using the in vitro simulated body fluid (SBF) soaking test, and the mechanism whereby apatite forms on the glass-ceramic surfaces in the SBF solution is discussed. The results indicate that the main crystal phase of the G-24 sample undergoing two heat treatment procedures is Ca5(PO4)3F (fluorapatite), and those of the G-2444 sample undergoing four heat treatment procedures are Ca5(PO4)3F and ß-CaSiO3 (ß-wollastonite). The heat treatment procedures are found to greatly influence the mechanical properties of the glass-ceramic, and an apatite layer is induced on the glass-ceramic surface after soaking in the SBF solution.

Effect of ginkgolide B-loaded self microemulsifying drug deliver system on pharmacokinetics of ginkgolide B in retina / 中华实验眼科杂志

Background Ginkgolide B (GB) has been proved to have neuroprotective and anti-apoptotic effects and can effectively inhibit apoptosis of retinal photoreceptor cells.But the high hydrophobic feature and low bioavailability of GB limit its clinical application.Self microemulsifying drug delivery system (SMEDDS) can effectively improve the infusibility drug dissolution and bioavailability in the retina.Objective This study was to investigate the pharmacokinetics and drug-time change of GB-loaded SMEDDS in retina.Methods Eighty SD rats were randomized into 2 groups,2.5％ GB(40 mg/kg) of SMEDDS or GB suspension(0.1％ DMSO dissolve) were gastrically given respectively in two groups.The rats were sacrificed and retinas were isolated 15,30,45 minutes and 1 hour,2,4,8,12 hours to prepare the retinal suspension.The content of GB in retina was assayed with high performance liquid chromatography-electrospray ionization-(1) (1)ss spectrum (HPLC-ESI-MS) and contrasted with standard curve.Practical drug dynamics program 3p87 was used to detect the pharmacokinetics parameters.The maximal content(Cmax,mg/g),time to peak (Tmax,h),clearance ratio (Ke/h),high-life period (t1/2) and area under the concentration-time curve(AUC0-∞,mg/(g · h)) of GB in various time points in retina after a single oral dose were calculated and compared between two groups.Results The standard curve was obtained over the concentration range of 1-32 mg/L with a linear regression equation,Y =0.0732X + 0.056 (r =0.992).A similar content-time curve was seen between GB suspension group and GB-SMEDDS group.The GB content was higher in GB-SMEDDS group than that in GB suspension group from 30 minutes through 12 hours after administration of drugs.The Cmax of GB-SMEDDS group and GB suspension group were(15.83±1.84) mg/g and(2.65±0.10) mg/g,the AUC0-∞ were(15.30±0.11)mg/(g· h)and(6.42±0.19)mg/(g · h).Conclusions HPLC-ESI-MS is proved to be a rapid,accurate,sensitive and suitable method for pharmocokinetic study of GB.SMEDDS can raise the concent of GB in retina,and it probably improve the bioavailability of GB.

Intravitreal triamcinolone acetonide in the treatment of macular edema due to retinal vein occlusion / 国际眼科杂志(Guoji Yanke Zazhi)

·AIM: To evaluate the efficacy and safety of intravitreal triamcinolone acetonide(TA) as treatment for macular edema associated with retinal vein occlusion(RVO).·METHODS: The study group consisting 30 patients (30 eyes) with RVO combined with macular edema received intravitreal 4mg TA. Changes in best-corrected visual acuity (BCVA), intraocular pressure(IOP), examination with slit-lamp microscope, fluorescein angiography and optical coherence tomography(OCT) were observed during the follow-up. Statistical analysis was conducted with SPSS 12.0 software.·RESULTS: The visual acuity(VA) of all patients was significantly improved and the central macular thickness (CMT) was significantly relieved. There was no correlation between course, age, CMT before injection and the type of RVO. There was positive correlation between visual acuity before injection and after injection.·CONCLUSION: Intravitreal injection of TA is an easy-operated and safe therapy. After injection, macular edema can be rapidly relieved. VA at baseline is the predictor for the prognosis of VA. Some patients experience recurrence of macular edema between 3 to 6 months after injection.

[Studies on properties of aggregates and Langmuir-Blodgett films for centrosymmetric naphthalocyanine molecules].

Deposition of Langmuir-Blodgett films and the aggregative properties of three centrosymmetric naphthalocyanine derivatives were investigated by using linear absorption spectra. Good LB films could be formed for all the three compounds. In dilute solution,the monomers are the main formation for the tetra-tert-butyl-cyan naphthalocyanine. Due to atomic zinc action, the tetra-tert-butyl naphthalocyanine zinc molecules could not only form H-aggregates, but also form J-aggregates. The tetra-tert-butyl naphthalocyanine zinc molecules mainly are aggregates in dilute solution. In the Langmuir-Blodgett films, both tetra-tert-butyl-cyan naphthalocyanine and tetra-tert-butyl-cyan naphthalocyanine zinc formed H-aggregates. The monomers are the main formation for the bi-( tetra-tertbutyl-naphthalocyaninato)-orbium in dilute solution and Langmuir-Blodgett films.