Identification of a Degradation Intermediate of the Momilactone A Rice Phytoalexin by the Rice Blast Fungus

We have already shown that major rice diterpene phytoalexin, momilactone A, was detoxified by Magnaporthe oryzae. We report here the identification by NMR, MS, and chemical synthesis of 3,6-dioxo-19-nor-9β-pimara-7,15-diene (1) as the degradation intermediate. Compound 1 exhibited similar antifungal activity to that of momilactone A, indicating 1 to be a precursor of possible detoxified compounds.     

蛇足石杉内生真菌Shiraia sp. Slf14中赖氨酸脱羧酶基因的克隆、表达及功能

【目的】阿尔茨海默症治疗药物石杉碱甲(Huperzine A,Hup A)的生物合成途径起始于赖氨酸脱羧酶(Lysine decarboxylase,LDC)。本研究克隆及表达了来源于产Hup A的植物内生真菌的LDC基因,并研究了其功能。【方法】采用RT-PCR扩增法,从一株产Hup A的蛇足石杉内生真菌Shiraia sp.Slf14获得LDC基因,构建表达质粒p ET-22b-LDC与p ET-32a-LDC,转化感受态细胞E.coli BL21,加入IPTG至终浓度为1×10~(–3) mol/L,于24°C、200 r/min培养8 h,诱导表达LDC蛋白质;通过Ni~(2+)金属亲和层析纯化重组LDC并建立酶促反应体系,利用TLC检测了LDC催化活性。利用生物信息学软件分析了LDC的理化性质及蛋白质的空间结构。【结果】成功克隆并异源表达出重组蛋白LDC与Trx-LDC,经SDS-PAGE电泳鉴定分子量分别为24.4 k Da和42.7 k Da,与预计大小相符。TLC结果表明LDC与Trx-LDC均具有赖氨酸脱羧酶活性。【结论】本研究从产Hup A的蛇足石杉内生真菌Shiraia sp.Slf14中成功克隆到LDC基因并进行了异源表达,检测到了其催化活性,为丰富LDC分子信息及阐明内生真菌中Hup A生物合成机制提供参考数据。     

Localization of the bioluminescence system in the pileus of Mycena chlorophos

Mycena chlorophos, which is primarily distributed in Southeast Asia, is a luminous fungus that emits a bright green light from its pileus for about 2 days at approximately 20°C and high relative humidity. The distribution of bioluminescent tissues in the whole pileus and its sections was heterogeneous. The light intensity in the cap and the upper region of the gill was greater than that in the lower region of the gill. At the microscopic level, the light was predominantly emitted from the membranes of hymenium and basidia cells on the gill. The emission was both cell and region specific. The luminescence system was localized in the cell membrane, and a part of the system was on the cell membrane surface. Copyright © 2015 John Wiley & Sons, Ltd.     

飞行质谱鉴定临床分离真菌准确度的Meta分析

目的基于循证医学系统性评价飞行质谱鉴定临床分离真菌的准确度,并与常规方法准确度进行比较。方法检索主要英文数据库PubMed、Cochrane、Web of Science,以及中文数据库CBM、万方、维普、知网数据库,检索飞行质谱鉴定临床分离真菌的原始文献。结果经筛选后纳入19篇文献(6609株真菌),Meta分析结果显示飞行质谱鉴定真菌至种水平正确率为0.9368(95%CI=0.9091～0.9598),常规方法鉴定真菌至种水平正确率为0.9104(95%CI=0.8874～0.9340);对结果进行了亚组分析,主要包括:菌株类型、研究类型、样本处理方法、金标准检测范围、鉴定阈值等;敏感性分析表明结果稳定可靠,Begg和Egger’s结果表明飞行质谱鉴定真菌不存在发表偏倚,常规方法鉴定真菌存在一定发表偏倚。结论基质辅助激光解吸电离-飞行时间质谱系统(MALDI-TOF MS)方法对鉴定临床致病性真菌准确率较高,是临床常规方法的可靠替代方法。     

Enantiomeric Polyketides from the Starfish‐Derived Symbiotic Fungus Penicillium sp. GGF16‐1‐2

One new racemic mixture, penicilliode A ( 1 ) and four pairs of enantiomeric polyketides, penicilliode B and C ( 2 and 3 ) and coniochaetone B and C ( 4 and 5 ), were obtained from the starfish‐derived symbiotic fungus Penicillium sp. GGF16‐1‐2. Interestingly, the strain GGF16‐1‐2 can produce enantiomers. The absolute configuration of 1 was determined by X‐ray diffraction (XRD) analysis, and the absolute configurations of 2 – 4 were determined by the optical rotation (OR) values and electronic circular dichroism (ECD) calculations. Compounds 1 – 5 were firstly isolated from the marine‐derived fungus Penicillium as racemates, and 2 – 5 were separated by HPLC with a chiral stationary phase. All the compounds were evaluated for their antibacterial, cytotoxic and inhibitory activities against PDE4D2.     

An interaction between climate change and infectious disease drove widespread amphibian declines

Climate change might drive species declines by altering species interactions, such as host–parasite interactions. However, few studies have combined experiments, field data, and historical climate records to provide evidence that an interaction between climate change and disease caused any host declines. A recently proposed hypothesis, the thermal mismatch hypothesis, could identify host species that are vulnerable to disease under climate change because it predicts that cool‐ and warm‐adapted hosts should be vulnerable to disease at unusually warm and cool temperatures, respectively. Here, we conduct experiments on Atelopus zeteki, a critically endangered, captively bred frog that prefers relatively cool temperatures, and show that frogs have high pathogen loads and high mortality rates only when exposed to a combination of the pathogenic chytrid fungus (Batrachochytrium dendrobatidis) and high temperatures, as predicted by the thermal mismatch hypothesis. Further, we tested various hypotheses to explain recent declines experienced by species in the amphibian genus Atelopus that are thought to be associated with B. dendrobatidis and reveal that these declines are best explained by the thermal mismatch hypothesis. As in our experiments, only the combination of rapid increases in temperature and infectious disease could account for the patterns of declines, especially in species adapted to relatively cool environments. After combining experiments on declining hosts with spatiotemporal patterns in the field, our findings are consistent with the hypothesis that widespread species declines, including possible extinctions, have been driven by an interaction between increasing temperatures and infectious disease. Moreover, our findings suggest that hosts adapted to relatively cool conditions will be most vulnerable to the combination of increases in mean temperature and emerging infectious diseases.     

A mid-Cretaceous trichomycete,Priscadvena corymbosa gen. et sp. nov., in Burmese amber

Priscadvena corymbosa gen. et sp. nov., is described from thalli and sporangia emerging from the oral cavity of a click beetle (Coleoptera: Elateridae) in mid-Cretaceous Burmese amber. The fossil contains several features unknown in extant Trichomycetes including a click beetle (Coleoptera: Elateridae) host, spiny, aerial thalli with the entire thallus bearing numerous small uninucleate globular spores and stalks attached to the oral cavity of its host. Based on these features, P. corymbosa gen. et sp. nov. is placed in a new family, Priscadvenaceae fam. nov., and new order, Priscadvenales ord. nov. The new morphological and behavioral features of the fossil add to the diversity of the trichomycetes as currently defined.     

Wood decay under the microscope

Many aspects of the interactions between host wood structure and fungal activity can be revealed by high resolution light microscopy, and this technique has provided much of the information discussed here. A wide range of different types of decay can result from permutations of host species, fungal species and conditions within wood. Within this spectrum, three main types are commonly recognised: brown rot, white rot and soft rot. The present review explores parts of the range of variation that each of these encompasses and emphasizes that degradation modes appear to reflect a co-evolutionary adaptation of decay fungi to different wood species or the lignin composition within more primitive and advanced wood cell types. One objective of this review is to provide evidence that the terms brown rot, white rot and soft rot may not be obsolete, but rigid definitions for fungi that are placed into these categories may be less appropriate than thought previously. Detailed knowledge of decomposition processes does not only aid prognosis of decay development in living trees for hazard assessment but also allows the identification of wood decay fungi that can be used for biotechnology processes in the wood industry. In contrast to bacteria or commercial enzymes, hyphae can completely ramify through solid wood. In this review evidence is provided that wood decay fungi can effectively induce permeability changes in gymnospermous heartwood or can be applied to facilitate the identification of tree rings in diffuse porous wood of angiosperms. The specificity of their enzymes and the mild conditions under which degradation proceeds is partly detrimental for trees, but also make wood decay fungi potentially efficient biotechnological tools.     

威海地区547例甲真菌病真菌培养结果分析

目的了解山东省威海地区甲真菌病的临床分类、菌种构成等流行情况。方法对547例镜检阳性的甲真菌病患者进行真菌培养、鉴定和临床分析。结果547例患者中真菌培养阳性423例,阳性率77.3%,远端侧位甲下型甲真菌病(DLSO)295例(53.9%),白色浅表型甲真菌病(SWO)36例(6.5%),近端侧位甲下型甲真菌病(PSO)78例(14.2%),全甲营养不良型甲真菌病(TDO)138例(25.2%)。共分离出429株真菌,其中皮肤癣菌354株(82.5%),酵母菌61株(14.2%),非皮肤癣菌霉菌14株(3.3%)。结论山东省威海地区甲真菌病病原体的分布以皮肤癣菌为主,其次为酵母菌和非皮肤癣菌霉菌,红色毛癣菌是最常见的皮肤癣菌,临床类型以DLSO型居多,其他依次是TDO、PSO、SWO。就诊人群中以20～50岁年龄段为最多见。