Biochemical characteristics of point mutated Capra hircus lysosome α-mannosidase.

Locoweeds, a type of poisonous weedare, are widely distributed throughout the world and have a significant impact on the development of herbivore animal husbandry. Swainsonine (SW), the main toxin in locoweeds, can competitively inhibit lysosomes α-mannosidase (LAM) in animal cells, resulting in α-mannosidosis. However, the specifics of the interaction between SW and LAM are still unclear. Here, we used molecular docking to predicte the interaction points between SW and LAM, built mutated lysosomes α-mannosidase (LAMM), and analyzed its biochemical properties changes in presumption points. The Trp at the 28th position and the Tyr at the 599th position of the LAM were interaction point candidates, and the above two amino acids in Capra hircus LAM (chLAM), were successfully mutated to glycine by constructing recombinant yeast GS115/PIC9K- LAMM. The results showed that the sensitivity of Capra hircus LAMM (chLAMM), to SW decreased significantly compared with wild-type LAM, the enzyme activity of LAM decreased approximately threefold, the optimum temperature of LAMM decreased from 55°C to 50°C, the optimum pH value increased from 4.5 to 5.0, and the effects of Mn2+, Fe3+, Al3+, Co2+, Cr3+, and ethylenediaminetetraacetic acid (EDTA) on LAM enzyme activity before and after point mutation changed significantly. These findings help us better understanding the molecular mechanism of the interaction mechanism between SW and chLAM, and provide new reference for solving locoweeds poisoning.

[Isolation and identification of berberine from endophytic fungi HL-Y-3].

The endophytic fungi HL-Y-3, which was isolated from the healthy leaves of Coptis chinensis, produced berberine when grown in the PDA culture medium. The presence of berberine was confirmed by the chromatographic and spectroscopic analyses. The yield of berberine was recorded as 9.313 µg•g⁻¹ by HPLC. The strain HL-Y-3 was identified as Alternaria sp.by morphological observation and 5.8S rDNA-ITS sequence analysis.The separation and purification of constituents were performed by PTLC. The mass spectrometry (MS) of the analyte was shown to be identical with authentic berberine.Further analysis with nuclear magnetic resonance (NMR) spectroscopy to showed that the chemical structure of the fungal berberine was identical with authentic berberine. The research provided new resources for the utilization of berberine.

Identification of a new locoweed (Oxytropis serioopetala) and its clinical and pathological features in poisoned rabbits.

By a series of experiments, we identified a new member of the locoweed family, Oxytropis serioopetala, that produces swainsonine, a phytotoxin harmful to livestock. In order to evaluate the toxicity of Oxytropis serioopetala, its extract was administered to ten rabbits by gavage at a dose of 1.5 mg/kg body weight as swainsonine once daily. After the 20th day, the rabbits appeared depressive and anorexic. In addition, intention tremors were apparent upon movement. Their eyes were dull. The rear limbs were severely weak and even progressed to partial paresis. The activities of serum aspartate aminotransferase (AST), alanine transaminase (ALT) and alkaline phosphatase (AKP) and urea nitrogen (BUN) levels in the poisoned rabbits increased significantly. Serum α-mannosidase (AMA) activity decreased markedly. Pathomorphological lesions in the locoweed-poisoned rabbits developed severe microvacuolation of visceral and neurological tissue. Extensive vacuolation was observed in the liver, kidney and brain. These clinical and pathological features are similar to the symptoms of locoism.

[Determination of zizybeoside II of Ziziphus jujuba by HPLC].

OBJECTIVE: To develop a quantitative method for determination of zizybeoside II in Ziziphus jujuba. METHOD: The samples were separated at 30 degrees C on a Zorbax SB-C18 column eluted with methanol-water (20 : 80) as the mobile phase. Flow rate was set at 1.0 mL x min(-1) and the detection wavelength was set at 210 nm. RESULT: The calibration curve was linear within the range from 0.046 to 0.582 microg (r = 0.999 9) and the average recovery was 97.2%. 12 batches of the crude drugs purchased from different areas were determined and the contents of zizybeoside II in Fructus Jujubae were fluctuated from 0.013% to 0.041%. CONCLUSION: The method is simple, repeatable and could be used for the quality control of Z. jujuba.