Enhanced production of Penicillium expansum PED-03 lipase through control of culture conditions and application of the crude enzyme in kinetic resolution of racemic Allethrolone

Alkaline lipase production was performed in submerged fermentation by Penicillium expansum PED-03. It was found that the suitable carbon source and nitrogen source for lipase production were 0.5% starch and 4.0% soybean meal, respectively. The maximal lipase activity (850 U/mL) of production was achieved at initial pH 5.5-6.0, 26 degrees C, 72 h. Tween-80 was an effective enhancer for lipase production. Agitation speed of the fermentor played an important role, and the suitable agitation speed for lipase production was 500 r/min. The lipase was stable within the range of pH 7.0-10.0 and 20-40 degrees C, and the optimum conditions for the enzymatic reaction were 35 degrees C and pH 9.5. The enzymatic resolution of racemic allethrolone (4-hydroxy-3-methyl-2-(2-propenyl)-2- cyclopenten-1-one) was carried out by the lipase from P. expansum PED-03, and the conversion reached 48% with excellent enantioselectivity (E > 100), which showed a good application potential in the production of optically pure allethrolone.     

KfoE encodes a fructosyltransferase involved in capsular polysaccharide biosynthesis in Escherichia coli K4

Escherichia coli K4 synthesizes a capsular polysaccharide (CPS) consisting of a fructose-branched chondroitin (GalNAc-GlcA(fructose)n), which is a biosynthetic precursor of chondroitin sulfate. Here, the role of kfoE in the modification of the chondroitin backbone was investigated using knock-out and recombinant complementation experiments. kfoE disruption and complementation had no significant effect on cell growth. CPS production was increased by 15 % in the knock-out strain, and decreased by 21 % in the knock-out strain complemented with recombinant kfoE. CPS extracted from the knock-out strain was chondroitin, whereas CPS extracted from the complemented strain was a fructose-branched chondroitin. The results demonstrated that the kfoE gene product altered the fructose group at the C3 position of the GlcA residue during production of K4CPS.     

两种锦鸡和环颈雉线粒体DNA(mtDNA)的比较研究

本文以10种限制性内切酶分析雉科中环颈雉,红腹锦鸡和白腹锦鸡线粒体DNA（mtDNA）。雉属与锦鸡属之间的遗传距离P为0.076（0.067-0.085）,红腹锦鸡与白腹锦鸡的P为0.012。推算雉属和锦鸡属的分化大约发生在3.8×10[6]年以前,红腹锦鸡与白腹锦鸡的分化大约在6×10[5]年以前。这些结果表明：1.在雉科系统发生中,雉属与锦鸡属是近缘的属;2.红腹锦鸡和白腹锦鸡的分化较晚,关系密切,可能只是两个亚种。     

光驱动二氧化碳转化系统的构建、优化与应用

利用光能驱动二氧化碳(carbon dioxide, CO₂)还原生产化学品对于缓解环境压力、解决能源危机具有重要意义。光捕获、光电转化和CO₂固定等作为影响光合作用效率的关键因素,同时也制约着CO₂的资源化利用效率。为了解决上述问题,本文从生物化学与代谢工程相结合的角度,系统总结了光驱动杂合系统的构建、优化与应用,并从酶杂合系统、生物杂合系统以及杂合系统应用3个方面分析了光驱动CO₂还原合成化学品的最新研究进展。在酶杂合系统方面,采用的策略主要有提升酶催化活性、增强酶稳定性等;在生物杂合系统方面,采用的方法主要包括增强生物捕光能力、优化还原力供应以及改善能量再生等;在杂合系统应用方面,主要阐述了光驱动CO₂还原生产一碳含能化合物、生物燃料以及生物食品等。最后,从纳米材料(包括有机材料和无机材料)和生物催化剂(包括酶和微生物)两个方面,展望了人工光合系统的进一步发展方向。     

论我国人口容纳量

人口环境容纳量是直接与社会生产力发展水平相适应的。它体现在人类智力发展水平、经济结构的合理性以及各人在行业中所占位置。本文据1982年人口普查10％抽样资料对我国劳动力分布进行了分析,并指出:劳动力分布不平衡反映出社会生产力的落后,自然资源与人力资源的浪费。我国的农牧渔业资源还有着巨大的潜力,只要国策对,人尽其才,物尽其用,使资源得到合理地开发和利用,今后50—100年内,我国农牧渔业资源将可满足15亿人口科学膳食需求。     

Electrospun Scaffold of Collagen and Polycaprolactone Containing ZnO Quantum Dots for Skin Wound Regeneration

Nanofibers(NFs)have been widely used in tissue engineering such as wound healing.In this work,the antibacterial ZnO quantum dots(ZnO QDs)have been incorporated into the biocompatible poly(ε-caprolactone)/collagen(PCL/Col)fibrous scaffolds for wound healing.The as-fabricated PCL-Col/ZnO fibrous scaffolds exhibited good swelling,antibacterial activity,and biodegradation behaviors,which were beneficial for the applications as a wound dressing.Moreover,the PCL-Col/ZnO fibrous scaffolds showed excellent cytocompatibility for promoting cell proliferation.The resultant PCL-Col/ZnO fibrous scaffolds containing vascular endothelial growth factor(VEGF)also exhibited promoted wound-healing effect through promoting expression of transforming growth factor-β(TGF-β)and the vascular factor(CD31)in tissues in the early stages of wound healing.This new electrospun fibrous scaffolds with wound-healing promotion and antibacterial property should be convenient for treating wound healing.     

A natural product enhances apoptosis via mitochondria/caspase-mediated pathway in HeLa cells

Cervical cancer is the fourth most lethal human malignancy and the leading cause of death among females around the world. Many antitumor agents have microbial origins. 5′-epi-SPA-6952A is a new 24-membered macrolide isolated from the cultured broth of Streptomyces diastatochromogenes. Therefore, we studied the activity and molecular mechanism of 5′-epi-SPA-6952A in human cervical carcinoma HeLa cell. The results showed that 5′-epi-SPA-6952A significantly inhibited cell proliferation and migration. In addition, 5′-epi-SPA-6952A obviously increased the production of intracellular reactive oxygen species and DNA damage in HeLa cells. Moreover, nuclear shrinkage of cells, decrease in mitochondrial membrane potential, and upregulation of Bax/Bcl-2 ratio resulted in the release of cytochrome c, and activation of caspase-9/3 was observed in HeLa cells treated with 5′-epi-SPA-6952A, which means it enhanced the intrinsic mitochondrial apoptosis. Besides, DNA-damage associated proteins poly (ADP-ribose) polymerase (PARP) and p53 were also studied, and the expressions of cleaved-PARP and p53 were drastically increased in HeLa cells treated with 5′-epi-SPA-6952A. Furthermore, we confirmed that 5′-epi-SPA-6952A affected the survival of HeLa cells by blocking cell cycle progression in the G1 phase. Taken together, the results shows that 5′-epi-SPA-6952A significantly inhibited HeLa cells proliferation via intrinsic mitochondrial apoptosis, cell cycle arrest, and blocking cell migration.     

异源表达NADH选择性氧化酶提高光滑球拟酵母酵解速率及丙酮酸生产强度

摘要：【目的】为进一步提高光滑球拟酵母(Torulopsis glabrata)葡萄糖代谢速率及丙酮酸生产强度。【方法】将源于荚膜胞浆菌(Histoplasma capsulatum)的编码选择性氧化酶的AOX1基因过量表达于T. glabrata中,获得了一株线粒体内NADH氧化途径发生改变且胞内总NADH 氧化酶活性提高1.8倍的重组菌株AOX。【结果】与出发菌株CON比较,细胞浓度以及发酵周期降低了20.3%和10.7%,而平均比葡萄糖消耗速率和丙酮酸合成速率分别提高了34.7%和54.1%。其原因     

小球藻热水提取物功能成分的活性跟踪分离

本研究旨在以自由基清除作用和促巨噬细胞增殖作用为导向,对小球藻热水提取物(CPE)的分离纯化产物进行活性跟踪,以确定CPE的主要功能成分。采用高压热水提取、Sevag除蛋白、乙醇沉淀和超滤的方法得到CPE粗多糖,然后通过DEAE52离子交换层析柱和Sephadex G-100对CPE粗多糖组分进一步分离纯化。研究结果表明,通过上述方法对CPE进行分离纯化,得到3种高活性成分PS-1-4-2、PS-1-3-2和PS-2-3-3,经凝胶渗透色谱GPC分析得知其分子质量分别为3.97×10~4 Da、2.28×10~4 Da和4.1×10~3 Da。活性跟踪结果表明,CPE能够清除自由基并促进巨噬细胞Ana-1细胞生长,主要是由于其多种活性组分共同发挥作用,清除自由基作用的功能成分主要集中于PS-1-3、PS-1-4、PS-2-3和PS-2-4,促Ana-1细胞增殖作用的功能成分主要集中于PS-1-3、PS-1-4和PS-2-3。本研究确立了CPE主要功能成分的活性筛选手段,并获得3种新型功能成分,可用于指导小球藻高附加值产品的开发,从而进一步推动微藻能源的产业化进程,实现"高附加值微藻产品、微藻能源与微藻固碳"一体化的示范作用。