曲霉sp.136的化学成分研究(英文)

从曲霉sp.136的固体发酵物中分离得到6个化合物.应用波谱分析及与已知品对照的手段将它们鉴定为烟曲霉酸(1)、(20S,22E,24R)-5α,8α-表二氧-麦角甾-6,22-二烯-3β-醇(2)、β-谷甾醇(3)、(2S,3S,4R)-2-[(2′R)-2′-羟基二十四烷酰氨基]-1,3,4-三羟基十八烷(4)、4-羟基苯乙酸(5)和烟碱酸(6).图1参

米曲霉氨基酰化酶酶法拆分制备D型芳香族氨基酸

以DL-苯丙氨酸为起始原料,乙酸酐乙酰化后得到N-乙酰DL-苯丙氨酸,利用米曲霉氨基酰化酶立体结构专一催化水解N-酰基-L-氨基酸的酰胺键的特点,分别得到L-苯丙氨酸和N-乙酰D-苯丙氨酸.通过结晶法分离两者后,N-乙酰D-苯丙氨酸经6mol/LHCl水解得到D-苯丙氨酸.由此拆分DL-苯丙氨酸得到光学纯度分别为98%的L-苯丙氨酸(收率84.8%,以原料N-乙酰-DL-苯丙氨酸的0.5倍摩尔量为理论产率)和92.3%的D-苯丙氨酸(收率89.5%).参2

耐热芽孢杆菌E2菌株纤维素酶基因克隆的研究

用质位ｐＢＲ３２２作载体，大肠杆菌Ｅ．ｃｏｌｉＤＨ５αＦ＇作受体，克隆到耐热芽孢杆菌Ｅ２菌株的羧甲基纤维素酶（ＣＭＣａｓｅ）基因。重组质粒ｐＢＧ３从产生ＣＭＣａｓｅ的转化子中分离得到。克隆到的ＣＭＣａｒｅ基因位于４．０ｋｂＨｉｎｄＩＩＩ片段上。功能状态ＣＭＣａｓｅ基因被亚克隆到２．４ｋｂＤＮＡ片段上。同位素杂交结果显示出克隆到的ＣＭＣａｓｅ基因与供体菌染色体ＤＮＡ的亲合性。重组质粒ｐＢＧ３所表达的ＣＭＣａｓｅ的最适作用ｐＨ为６．５，最适作用温度为５５℃，不作用于任何实验过的天然纤维素。含重组质粒ｐＢＧ３

地涌金莲的化学成分

目的　研究地涌金莲 Musella lasiocarpa全草中的化学成分。方法　用甲醇室温浸提 ,溶剂萃取分段 ,硅胶柱层析分离纯化 ,波谱分析鉴定结构 ,体外抑菌实验测试抗菌活性。结果　从该植物全草中分离出 4个phenylphenalenone型化合物 ,通过波谱分析将其分别鉴定为 :2 - hydroxy- 9- (4′- hydroxyphenyl) - phenalen- 1- one( )、 2 - methoxy- 9- (4′- hydroxyphenyl) - phenalen- 1

Determination of the number of ψ(3686) events taken at BESIII

The number of ψ(3686) events collected by the BESIII detector during the 2021 run period is determined to be (2259.3±11.1)×106 by counting inclusive ψ(3686) hadronic events. The uncertainty is systematic and the statistical uncertainty is negligible. Meanwhile, the numbers of ψ(3686) events collected during the 2009 and 2012 run periods are updated to be (107.7±0.6)×106 and (345.4±2.6)×106, respectively. Both numbers are consistent with the previous measurements within one standard deviation. The total number of ψ(3686) events in the three data samples is (2712.4±14.3)×10^

Measurement of integrated luminosity of data collected at 3.773 GeV by BESIII from 2021 to 2024

We present a measurement of the integrated luminosity e+e- of collision data collected by the BESIII detector at the BEPCII collider at a center-of-mass energy of Ecm = 3.773 GeV. The integrated luminosities of the datasets taken from December 2021 to June 2022, from November 2022 to June 2023, and from October 2023 to February 2024 were determined to be 4.995±0.019 fb-1, 8.157±0.031 fb-1, and 4.191±0.016 fb-1, respectively, by analyzing large angle Bhabha scattering events. The uncertainties are dominated by systematic effects, and the statistical uncertainties are negligible. Our results provide essential input for future analyses and precision measurements