芳香聚酮类化合物产生菌的分子筛选及其代谢产物的研究

目的 建立一种芳香聚酮类化合物产生菌的基因筛选方法并获得相应结构类型的化合物.方法 依据芳香聚酮类化合物生物合成途径所用的Ⅱ型酮基合酶的同源性设计简并引物,通过PCR方法扩增出约0.6kb目的基因片段,同时通过同源进化和抗菌活性分析对海洋放线菌是否产生芳香聚酮类化合物进行早期评估,并最终从阳性菌中分离得到相应结构类型的化合物.结果 利用建立的芳香聚酮类化合物产生菌基因筛选体系对100株海洋放线菌进行筛选,获得了18株携带Ⅱ型酮基合酶基因的阳性菌株,通过同源进化和抗菌活性分析后从中筛选到1株与多环氧杂蒽酮类化合物lysolipin和xantholipin的酮基合酶基因同源的野野村菌(Nonomuraea sp.)FIM02-765,并最终从该菌中分离得到多环氧杂葸酮类化合物simaomicin α.结论 本研究通过聚酮合酶编码基因的同源进化分析以及建立起来的Ⅱ型酮基合酶基因与化合物之间的联系,验证了芳香聚酮类化合物产生菌的基因筛选方法的可行性,同时本文还首次从野野村菌(Nonomuraea sp.)中分离得到多环氧杂葸酮类化合物simaomicin α,这些都为高效利用海洋放线菌资源和基因资源奠定了一定的基础.     

海星共附生真菌Penicillium sp．GGF16－1－2中次级代谢产物研究

目的 全球天然产物社会分子网络（GNPS）和单菌株多次级代谢产物（OSMAC）策略从海洋微生物中寻找结构新颖、活性好的次生代谢产物。方法 在GNPS指导下，通过硅胶柱层析及半制备高效液相色谱（HPLC）等方法对海星共附生真菌penicillium sp. GGF16-1-2在不同培养基的次级代谢产物进行分离纯化。通过核磁共振（NMR）、高分辨质谱（HRMS）、旋光（ORD）和圆二色光谱（CD）等现代波谱解析方法以及对比文献确定化合物的结构。结果 在GNPS追踪指导下从penicillium sp. GGF16-1-2中D培养基分离得到9个聚酮类化合物，依次为phenol A（1）、decarboxydihydrocitrinone（2）、stoloniferol B（3）、sclerotinin A（4）、(1S,3R,4S)-1-(4"-hydroxyl-phenyl)-3,4-dihydro-3,4,5-trimethyl-1H-2- benzopyran-6,8-diol（5）、β-diversonolic ester（6）、sydowinin A（7）、ω-hydroxy-emodin（8）和dibutyl phthalate（9）。而在真1培养基中GNPS预测到二聚体类成分存在，并在GNPS指导下初步分离得到桔霉素二聚类化合物：citrinin H1（10）和dicitrinone B（11）。结论 OSMAC策略和GNPS可以预测并获得骨架丰富、结构新颖的化合物。对海星共附生真菌penicillium sp. GGF16-1-2次生代谢产物研究发现真1培养基比D培养基更适合桔霉素二（多）聚体类化合物的产生。     

牛樟芝非还原型聚酮合酶基因的克隆及表达分析

目的获得牛樟芝聚酮合酶基因(Ac PKS1)全长,对其进行生物学分析并分析该基因在不同培养基上的表达差异。方法通过对牛樟芝基因组分析获得牛樟芝聚酮合酶基因,通过设计含有起始密码子和终止密码子的特异引物并以牛樟芝c DNA为模板克隆得到Ac PKS1基因全长,并对该基因进行生物信息学分析及在不同培养基上的表达谱分析。结果 Ac PKS1全长6 348 bp,含有6个内含子和7个外显子,外显子编码2 115个氨基酸;通过生物信息学分析,推测该基因为真菌I型非还原型PKS,结构域为SAT-KS-PT-ACP-ACP-TE,系统树分析显示Ac PKS1与其他未知功能的聚酮合酶(PKS)聚为一支,说明Ac PKS1可能是一种新的聚酮化合物环化方式;表达谱分析表明,葡萄糖为Ac PKS1基因表达的必要条件,且葡萄糖含量与Ac PKS基因表达量呈正相关。结论本研究为Ac PKS1功能鉴定以及牛樟芝基因资源利用奠定基础。     

Lipidomic analysis reveals the significant increase in diacylglycerophosphocholines in umbilical cord blood from pregnant women with gestational hypercholesterolemia

Gestational hypercholesterolemia has been recognized as a risk factor of some pregnancy complications. We supposed that maternal hypercholesterolemia modified the lipid profile of the fetus. Thirty pregnant women with hypercholesterolemia and matched controls were recruited and cord blood was sampled. Lipidomic analysis was used to evaluate the lipid profile change between the two groups. The results showed that the content of diacylglycerophosphocholines (PC) was significantly high in cord blood from hypercholesterolemic pregnant women. PC (16:0/20:4) and PC (18:0/20:4) were selected as the most important lipid species in cord plasma and their contents were positively related to the total cholesterol and high-density lipoprotein cholesterol levels in cord blood. The contents of these two PCs were significantly higher in the hypercholesterolemic group than in the control group. These results suggested that gestational hypercholesterolemia might program the phospholipid metabolism in offspring.     

Antiproliferative properties of polyketides isolated from Virola sebifera leaves

An activity-guided fractionation of Virola sebifera Aubl. methylene chloride-soluble fraction provided novel 3,5-dihydro-2-(1'-oxo-3'-hexadecenyl)-2-cyclohexen-1-one (3), two known lignans (1, 2) and dehydro hexadecanoyl resorcinol (4). Isolation and purification were conducted with the application of column chromatography and structures were assigned by spetral analysis (1D and 2D NMR, HREIMS). Compounds 1-4 were evaluated for cytotoxic activities against human tumour cell lines UACC62 (melanoma), MCF-7 (breast), NCI 460 (lung, non-small cells), OVCAR03 (ovarian), PC-03 (prostate), HT-29 (colon), 786-0 (renal) and NCI-ADR (breast expressing phenotype multiple drugs resistance) in vitro. The new polyketide (3) showed selectivity against human OVCAR03 and NCI-ADR cell lines, ranging from 2 to 4 microg/mL.     

海洋放线菌中具有抗肿瘤活性聚酮类化合物的研究进展

目的对海洋放线菌所产生的聚酮类化合物的结构特点与抗肿瘤活性进行阐述,为海洋放线菌的进一步研究与开发奠定基础。方法结合相关文献33篇,对近5年来海洋放线菌次级代谢产物中发现的结构新颖复杂的聚酮类化合物的结构特征和抗肿瘤活性研究进行综述。结果与结论聚酮类化合物结构新颖复杂,对多种瘤株都表现出较强的抑制作用,且部分化合物已经处于临床实验阶段。     

Emergent gene order in a model of modular polyketide synthases

Polyketides are a class of biologically active heteropolymers produced by assembly line-like multiprotein complexes of modular polyketide synthases (PKS). The polyketide product is encoded in the order of the PKS proteins in the assembly line, suggesting that polyketide diversity derives from combinatorial rearrangement of these PKS complexes. Remarkably, the order of PKS genes on the chromosome follows the order of PKS proteins in the assembly line: This fact is commonly referred to as “collinearity”. Here we propose an evolutionary origin for collinearity and demonstrate the mechanism by using a computational model of PKS evolution in a population. Assuming continuous evolutionary pressure for novel polyketides, and that new polyketide pathways are formed by horizontal transfer/recombination of PKS-encoding DNA, we demonstrate the existence of a broad range of parameters for which collinearity emerges spontaneously. Collinearity confers no fitness advantage in our model; it is established and maintained through a “secondary selection” mechanism, as a trait which increases the probability of forming long, novel PKS complexes through recombination. Consequently, collinearity hitchhikes on the successful genotypes which periodically sweep through the evolving population. In addition to computer simulation of a simplified model of PKS evolution, we provide a mathematical framework describing the secondary selection mechanism, which generalizes beyond the context of the present model.     

Aspergchromones A and B,two new polyketides from the marine sponge-associated fungus Aspergillus sp. SCSIO XWS03F03

Two new polyketides, aspergchromones A (1) and B (2), together with five known compounds, secalonic acid D (3), noreugenin (4), (3S)-5-hydroxymellein (5), (4S)-6-hydroxyisosclerone (6), and (-)-regiolone (7), were isolated from the ethyl acetate extract of marine sponge-derived fungus Aspergillus sp. SCSIO XWS03F03. Their structures were elucidated by means of spectroscopic techniques (1D and 2D NMR, MS, UV, and IR). The absolute configurations of the new compounds were established by ECD calculations. Compound 3 showed moderate antimicrobial activity.     

人参内生真菌Aspergillus terreus RSB2007的次生代谢产物的研究

目的 研究人参内生真菌Aspergillus terreus RSB2007次生代谢产物的化学成分,以期发现新的化合物。方法 该菌大米固体发酵的醋酸乙酯提取物经硅胶、Sephadex LH-20及HPLC等多种色谱技术进行分离纯化,并根据核磁共振谱、质谱、圆二色谱（electronic circular dichroism,ECD）以及计算ECD等方法鉴定化合物的结构。结果 从人参内生真菌Aspergillus terreus RSB2007发酵产物中初步分离鉴定了4个化合物,分别鉴定为7,8''-二羟基-3,4,6-三甲基-7''-苯基-1,3,4,7''-四氢-2H-吡喃并[2,3,4-de]色烯-8''-羧酸盐（1）、butyrolactone II（2）、aspernolide A（3）和versicolactone B（4）。结论 化合物1为新的聚酮类化合物,命名为曲霉酮A。