茭白黑粉菌对紫红曲霉部分代谢产物的影响

茭白黑粉菌(Ustilago esculentaHenn)与紫红曲霉(Monascus purpureusWent)共同培养,测定培养物中洛伐他汀、橘霉素、色价的含量。结果表明,在第8 d添加茭白黑粉菌的效果较好。当接种量为2 mL,孢子浓度3.42×108个/mL,洛伐他汀、橘霉素的含量比对照提高203%、274%,但色价却下降24%。形态观察发现,HF菌抑制红曲霉菌丝分支和子囊孢子的形成并导致菌丝的空泡增多。     

红曲中桔霉素的Ames试验

采用鼠伤寒沙门氏菌试验(Ames试验),通过观察0.2、1.0、5.0、25.0 μg/皿桔霉素处理对鼠伤寒沙门氏菌组氨酸缺陷型菌株TA97、TA98、TA100、TA102回复突变的影响,检测红曲中桔霉素的致突变性.结果表明,桔霉素受试物组回变菌落数均未超过自发回变菌落数的2倍,亦未呈现剂量反应关系,试验结果为阴性,红曲中桔霉素未表现出致突变性.     

Preparation and Antioxidant Activity of Chitosan Dimers with Different Sequences

As a popular marine saccharide, chitooligosaccharides (COS) has been proven to have good antioxidant activity. Its antioxidant effect is closely related to its degree of polymerization, degree of acetylation and sequence. However, the specific structure–activity relationship remains unclear. In this study, three chitosan dimers with different sequences were obtained by the separation and enzymatic method, and the antioxidant activity of all four chitosan dimers were studied. The effect of COS sequence on its antioxidant activity was revealed for the first time. The amino group at the reducing end plays a vital role in scavenging superoxide radicals and in the reducing power of the chitosan dimer. At the same time, we found that the fully deacetylated chitosan dimer DD showed the strongest DPPH scavenging activity. When the amino groups of the chitosan dimer were acetylated, it showed better activity in scavenging hydroxyl radicals. Research on COS sequences opens up a new path for the study of COS, and is more conducive to the investigation of its mechanism.     

红曲菌产毒相关基因的克隆及序列分析

通过分子生物学软件,从产桔霉素相关的红曲菌cDNA消减文库中找出20个与桔霉素合成相关的差异序列,并用BLAST软件对这些序列进行同源比对,分析其功能.将消减文库中PS基因进行5'RACE后电子拼接获得的全长cDNA,再与其基因组DNA进行对比,从而获得完整基因结构并做特性分析,为筛选红曲菌中产桔霉素基因提供理论依据.     

Protective effect of the isoflavone equol against DNA damage induced by ultraviolet radiation to hairless mouse skin

Equol, an isoflavonoid metabolite produced from the dietary isoflavone daidzein by the gut microflora in mammals, has been found to protect not only against ultraviolet (UV) radiation-induced cutaneous inflammation and photoimmune suppression, but also have anti-photocarcinogenic properties in mice. Because the state of DNA damage has been correlated with suppression of the immune system and photocarcinogenesis, we have therefore examined the potential of equol to offer protection from solar-simulated UV (SSUV) radiation-induced DNA damage in hairless mice by the immunohistochemical approach using monoclonal antibody specific for cyclobutane pyrimidine dimers (CPDs; H3 antibody). Topical application of 20 µM equol lotion, which was applied both before and after SSUV significantly reduced the number of CPDs. This reduction was evident immediately after SSUV exposure, at 1 h after exposure, and at 24 h after exposure, revealing 54%, 50%, and 26% reduction in CPDs, respectively. When the same concentration was applied for 5 consecutive days after SSUV exposure, there was no significant difference in the reduction of CPDs immediately after SSUV irradiation or at 1 hour afterwards, but there were significant reductions of 23% and 42% at 24 and 48 h after SSUV exposure, respectively. Despite apparently reducing the number of CPDs post-SSUV, topically applied equol did not appear to increase the rate of dimer removal. To conclude, equol applied topically prior to SSUV irradiation offers protection against CPD formation in hairless mice, possibly by acting as a suncreen and thus inhibiting DNA photodamage.     

Andalasin A, a new stilbene dimer from Morus macroura

A new stilbene dimer, andalasin A (1), together with the known stilbene oxyresveratrol and the 2-arylbenzofuran glycoside mulberroside C, have been isolated from the wood of Morus macroura. The structure of the new compound was elucidated on the basis of spectroscopic data. Compound 1 shows weak antinematodal and moderate antifungal properties.     

Taxonomy of Penicillium section Citrina

Species of Penicillium section Citrina have a worldwide distribution and occur commonly in soils. The section is here delimited using a combination of phenotypic characters and sequences of the nuclear ribosomal RNA gene operon, including the internal transcribed spacer regions ITS1 and ITS2, the 5.8S nrDNA (ITS) and partial RPB2 sequences. Species assigned to section Citrina share the production of symmetrically biverticillate conidiophores, flask shaped phialides (7.0-9.0 μm long) and relatively small conidia (2.0-3.0 μm diam). Some species can produce greyish-brown coloured cleistothecia containing flanged ascospores. In the present study, more than 250 isolates presumably belonging to section Citrina were examined using a combined analysis of phenotypic and physiological characters, extrolite profiles and ITS, β-tubulin and/or calmodulin sequences. Section Citrina includes 39 species, and 17 of those are described here as new. The most important phenotypic characters for distinguishing species are growth rates and colony reverse colours on the agar media CYA, MEA and YES; shape, size and ornamentation of conidia and the production of sclerotia or cleistothecia. Temperature-growth profiles were made for all examined species and are a valuable character characters for species identification. Species centered around P. citrinum generally have a higher maximum growth temperature (33-36 °C) than species related to P. westlingii (27-33 °C). Extrolite patterns and partial calmodulin and β-tubulin sequences can be used for sequence based identification and resolved all species. In contrast, ITS sequences were less variable and only 55 % of the species could be unambiguously identified with this locus. TAXONOMIC NOVELTIES: Penicillium argentinense Houbraken, Frisvad & Samson, P. atrofulvum Houbraken, Frisvad & Samson, P. aurantiacobrunneum Houbraken, Frisvad & Samson, P. cairnsense Houbraken, Frisvad & Samson, P. christenseniae Houbraken, Frisvad & Samson, P. copticola Houbraken, Frisvad & Samson, P. cosmopolitanum Houbraken, Frisvad & Samson, P. neomiczynskii Cole, Houbraken, Frisvad & Samson, P. nothofagi Houbraken, Frisvad & Samson, P. pancosmium Houbraken, Frisvad & Samson, P. pasqualense Houbraken, Frisvad & Samson, P. quebecense Seifert, Houbraken, Frisvad & Samson, P. raphiae Houbraken, Frisvad & Samson, P. terrigenum Seifert, Houbraken, Frisvad & Samson, P. ubiquetum Houbraken, Frisvad & Samson, P. vancouverense Houbraken, Frisvad & Samson, P. wellingtonense Cole, Houbraken, Frisvad & Samson.     

Fusaripyridines A and B; Highly Oxygenated Antimicrobial Alkaloid Dimers Featuring an Unprecedented 1,4-Bis(2-hydroxy-1,2-dihydropyridin-2-yl)butane-2,3-dione Core from the Marine Fungus Fusarium sp. LY019

The fungal strain, Fusarium sp. LY019, was obtained from the Red Sea sponge Suberea mollis. Bioassay-directed partition of the antimicrobial fraction of the extract of the culture of the fungus provided two dimeric alkaloids, fusaripyridines A and B (1 and 2). The compounds possess a previously unreported moiety, 1,4-bis(2-hydroxy-1,2-dihydropyridin-2-yl)butane-2,3-dione. Further, the compounds display a highly oxygenated substitution pattern on the dihydropyridine moieties, representing an additional feature of the fusaripyridines. Fusaripyridines A and B are the first examples of natural products possessing 1,4-bis(2-hydroxy-1,2-dihydropyridin-2-yl)butane-2,3-dione backbone. Careful analyses of the one- and two-dimensional NMR and HRESIMS spectra of the compounds secured their structural mapping, while their absolute stereochemistry was established by analyses of their ECD spectra. The production of such dimeric alkaloids with an unprecedented moiety in the culture of Fusarium sp. LY019 supports further understanding of the biosynthetic competences of the cultured marine-derived fungi. Fusaripyridines A and B selectively inhibited the growth of Candida albicans with MIC values down to 8.0 µM, while they are moderately active against S. aureus, E. coli and HeLa cells.     

绿豆幼苗UV-B敏感性与环丁烷嘧啶二聚体累积的关系

【目的】明确绿豆品种间UV-B敏感性的差异与环丁烷嘧啶二聚体（CPDs）累积间的关系。【方法】采用单克隆抗体ELISA法，研究0.4 W·m-2UV-B对两绿豆品种中绿-1和秦豆-20（Phaseolus raditus L. cv. Zhonglü-1 and Qindou-20）幼苗叶片DNA链内环丁烷嘧啶二聚体（CPDs）的诱导形成及其光、暗修复，并对CPDs累积与绿豆UV-B敏感性的关系进行分析。【结果】两品种绿豆幼苗经UV-B处理4 d后，中绿-1叶片的生物量和净光合速率被抑制的程度明显低于秦豆-20，说明中绿-1对UV-B的敏感性低于秦豆-20。相应中绿-1叶片DNA中CPDs累积量和其形成能力也都低于秦豆-20，光修复能力明显高于秦豆-20，而两品种CPDs的暗修复能力基本相同，且均显著低于光修复能力。【结论】两品种幼苗CPDs形成能力和光修复能力的不同造成了两品种幼苗叶片在可见光下CPDs累积量的不同，进而可能导致了绿豆品种间UV-B敏感性的不同。另外，两品种CPDs形成能力的差异与紫外吸收物质含量有关。