蝉棒束孢内菌核、菌膜及其生境土壤真菌群落结构及生态功能分析

通过分析蝉棒束孢Isaria cicadae内菌核、菌膜及其生境土壤的真菌群落结构与核心真菌组的生态功能,初步探索蝉棒束孢自然生长过程中内环境真菌与其周围环境中真菌的关系。本研究利用高通量测序技术检测6株采自贵阳大将山和贵阳森林公园的蝉棒束孢及土壤样本,结果表明,蝉棒束孢内菌核共检测到43个真菌属,菌膜检测到58个真菌属,菌际土检测到260个真菌属,且内菌核和菌膜真菌群落结构相似。而两地生境土的真菌群落结构有差异,大将山以棒束孢属Isaria、被孢霉属Mortierella和一分类地位未知属占优势,而贵阳森林公园以被孢霉属、隐球酵母属Cryptococcus、红菇属Russula、棒束孢属占优势,且两地菌际土中棒束孢属的丰度均显著高于其他土样。核心真菌组检测分析显示,内菌核的核心真菌组有10个OTUs,菌膜的核心真菌组有5个OTUs,菌际土的核心真菌组有20个OTUs,3种样本的核心真菌组的生态功能群均检测到有与植物相关的功能群,内菌核中检测到外生菌根真菌群,菌膜中检测到植物病原真菌群,菌际土中检测到丛枝菌根真菌群和植物病原菌群。     

十种虫生真菌液体培养芽生孢子的形态发生

芽生孢子是许多真菌通过出芽方式产生的无性孢子,在液体发酵中主要以这种形式大量繁殖。真菌杀虫剂活性成分分生孢子的大量生产使用液体发酵得到的芽生孢子作为接种物,另外,它也是当今虫生真菌遗传转化的重要受体,因而研究虫生真菌芽生孢子的形态和发生特点具有重要意义。本研究分别对液体发酵中的球孢白僵菌、粉棒束孢、蝉棒束孢、环链棒束孢、玫烟色棒束孢、细脚棒束孢、斜链棒束孢、金龟子绿僵菌、蝗绿僵菌和蜡蚧霉等10种常见虫生真菌芽生孢子的形成过程进行显微观察,了解其分生孢子产生过程的异同。结果表明,芽生孢子的产生方式有两种类型：1）蝉棒束孢在其整个生活史中以菌丝生长为主,芽生孢子产生的数量很少。2）其他各种真菌芽生孢子产生方式相似,在菌丝体形成后就开始大量以菌丝出芽或缢缩产生芽生孢子,接着还可通过芽生孢子的出芽或缢缩断裂产生新的芽生孢子。芽生孢子的产生分为3个时期：初期先由菌丝形成芽生孢子;指数期芽生孢子大量增殖,菌丝和芽生孢子都可产生芽生孢子;后期以芽生孢子产新芽生孢子为主要方式。     

蝉科昆虫病原真菌物种多样性（英文）

蝉科昆虫在自然界具有重要作用,是果树等林木的刺吸性害虫,同时蝉与真菌组成的虫菌共生体也具有重要经济价值。近十年来,通过对我国昆虫病原真菌资源的调查,共采集获得102株蝉科昆虫罹患病原真菌标本,并保存于安徽农业大学昆虫病原真菌研究中心(RCEF)。本研究从蝉科罹患病原真菌标本中分离得到81株菌株,并对其多样性进行了研究。基于不同培养基的形态特征观察并结合ITS、SSU、LSU、TEF、RPB1和RPB2基因构建系统发育树,发现寄生蝉科的菌株属于3科6属15种。本研究重点描述了一个中国新记录种——高水紫孢菌;此外,一些类棒束孢属菌株被修订为蝙蝠蛾萨姆森菌;除上述物种外,还鉴定出球孢白僵菌、绿色绿僵菌、蝉花虫草、柱孢绿僵菌、环链虫草、玫烟色虫草、澳洲白僵菌、布氏白僵菌、细脚虫草、棕色绿僵菌和长座细虫草。其中球孢白僵菌、蝉花虫草和绿色绿僵菌是优势种,多度达总数的58%。而其他12个物种分离频率较低。     

4种虫草相关真菌菌丝体粗多糖的生物活性评价

本研究以细脚棒束孢、蛹虫草、蝉棒束孢和球孢白僵菌的菌丝体粗多糖为对象,分析4种虫草相关真菌菌丝体粗多糖含量与生物量的相关性,并进一步对其抗氧化能力和抗肿瘤活力进行评价.液体发酵结果表明,蝉棒束孢MF12、MF13和蛹虫草MF27、MF1的菌丝体粗多糖含量(＞40mg/g)显著高于其他菌株,蝉棒束孢MF11、MF13和蛹...     

玫烟色棒束孢(Isaria fumosorosea)侵染小菜蛾的表达谱分析

【背景】昆虫病原真菌对寄主的侵染是一个十分复杂的过程,是多基因共同作用的结果。玫烟色棒束孢(Isaria fumosorosea) IFCF01菌株对小菜蛾具有很高的致病力,然而有关玫烟色棒束孢对小菜蛾致病的相关基因少见报道。【目的】筛选玫烟色棒束孢侵染小菜蛾相关基因,为更好地利用玫烟色棒束孢防治小菜蛾提供基因靶点。【方法】采用第二代高通量测序技术RNA-Seq,对玫烟色棒束孢侵染小菜蛾2–3龄幼虫4、8、12、16、24、30、36 h的虫菌混合样品(处理组)及纯培养玫烟色棒束孢(对照组)进行测序分析并筛选差异表达基因,结合生物信息学方法分析差异基因涉及的功能模块和信号通路。【结果】玫烟色棒束孢侵染小菜蛾混合样品与纯培养玫烟色棒束孢对照组对比分析共获得28 384个差异基因,其中显著差异表达基因274个,上调表达118个,下调表达156个。筛选获得的显著差异表达基因,特别是上调表达基因可能与玫烟色棒束孢对小菜蛾的侵染有关。GO二级分类显示,差异表达基因能够注释到36个GO条目中,包含18个生物学过程、9个细胞组分和9个分子功能。KEGG通路分析显示共有171个差异表达基因(differentially expressed gene,DEG)注释到132个通路中,其中有66个DEG显著富集在14个通路中。这些显著差异表达基因中大部分为玫烟色棒束孢侵染过程中潜在致病毒力相关基因。【结论】本研究为筛选玫烟色棒束孢侵染小菜蛾致病相关基因提供重要数据库,也为阐明玫烟色棒束孢对小菜蛾的侵染机制提供基础。     

盐胁迫对昆虫病原真菌环链棒束孢生长及基因表达的影响

环链棒束孢Isaria cateniannulata是一种重要的昆虫病原真菌,广泛应用于茶园害虫的防治.环境胁迫是影响该菌株生长、扩散和菌株毒力的不利外界因素,其中盐胁迫对环链棒束孢的生长和基因转录表达的影响尚不清楚.本研究采用o(对照)、0.6和1.0mol/L的NaCl处理菌株,观测不同浓度NaCl对菌株表型的生长...     

三种森林生态系统昆虫病原真菌优势种生态位比较

研究了天然阔叶林、天然阔叶次生林和马尾松人工纯林3种不同森林生态系统中昆虫病原真菌优势种的数量组成及生态位宽度和生态位重叠值.结果表明:球孢白僵菌在这3种森林生态系统中分别为第三、第一和第二优势种.该菌在3种森林生态系统中的营养生态位宽度和时间生态位宽度均最大,远大干环链棒束孢、粉棒束孢和细脚棒束孢等优势种;该菌与其他优势种的时间生态位重叠值较大,而营养生态位重叠值较小.球孢白僵菌在3种森林生态系统中都是发生时间最长、寄主昆虫最丰富、适应环境能力最强的昆虫病原真菌.     

盐胁迫对昆虫病原真菌环链棒束孢生长及基因表达的影响（英文）

环链棒束孢Isaria cateniannulata是一种重要的昆虫病原真菌,广泛应用于茶园害虫的防治。环境胁迫是影响该菌株生长、扩散和菌株毒力的不利外界因素,其中盐胁迫对环链棒束孢的生长和基因转录表达的影响尚不清楚。本研究采用0 (对照)、0.6和1.0mol/L的NaCl处理菌株,观测不同浓度NaCl对菌株表型的生长抑制作用,并对3组处理做了转录组分析。结果表明,3组处理共拼接到37 833个转录本,得到10 441个unigenes。与对照组相比,0.6和1.0mol/L NaCl处理组共鉴定出1 074个和2 412个差异表达基因,其中697个和1 201个表达上升,377个和1 211个表达下降。这些差异表达基因分别参与了碳水化合物和氨基酸的代谢、核糖体的生物合成、脂肪酸的合成与降解。为了验证转录组结果的准确性,本研究进一步通过qRT-PCR技术验证了 12个差异表达基因的表达谱,研究结果为进一步了解环链棒束孢抵抗盐胁迫的分子机理奠定了理论基础。     

蝉棒束孢显微形态变异式样

【目的】揭示蝉棒束孢居群形态性状的变异式样。【方法】通过对15个居群,75个蝉棒束孢菌株17个显微形态性状的观察和测量,采用SAS 8.1软件对蝉棒束孢显微形态性状数据进行描述性、巢式方差和Q聚类分析,获得蝉棒束孢显微形态变异数据。【结果】蝉棒束孢具有大小两型分生孢子,产孢细胞的形态可分为葫芦状和瓶状2种类型;蝉棒束孢在PDA培养基中易形成数量众多的厚垣孢子,菌丝间多能形成融合菌丝,并可观察到少量的融合菌丝在厚垣孢子与菌丝间、产孢细胞间形成。描述性分析表明,蝉棒束孢居群17个形态性状的变异系数(CV)在13.07%–104.09%之间,在物种水平上表现出丰富的变异;巢式方差分析表明,蝉棒束孢显微形态性状在居群间平均方差分量占总变异的11.29%,居群内个体间平均方差分量占总变异的15.27%,菌株内观察值间平均方差分量占总变异的73.44%。【结论】蝉棒束孢菌株形态性状变异丰富,是形态性状变异的主要来源,蝉棒束孢居群显微形态性状不存在明显的地理相关性。     

不同培养时间下蝉棒束孢菌丝体的代谢组研究

利用LC-MS对不同培养时间蝉棒束孢菌丝体代谢物进行检测,结合多变量统计分析的主成分分析(PCA)和正交偏最小二乘判别分析(OPLS-DA)鉴定差异化合物。PCA和OPLS-DA表明蝉棒束孢菌丝体中的代谢物随培养时间不同有显著变化。阴、阳离子模式下我们都可以把蝉棒束孢代谢物变化分为前期、中期和后期3个时期。培养前期产生较多的细胞松弛素E、肌醇、γ-氨基丁酸、乙酰肉碱、亚油酸等与侵染宿主、早期信号传导和氧化供能有关的物质;中期产生较多的甘露醇、海藻糖、亚麻酸、柠檬酸、丙酮酸、7,8-二羟基油酸等与抗逆和氧化供能有关的物质,此外还有两种抗生素红酵母红素、δ-氨基-γ-酮戊酸达到了最大值;培养后期产生较多的脯氨酸、2,4-二氨基丁酸、3′-deoxy-hanasanagin、ulvaline、赤霉素、烟酰胺等与抗逆、抗氧化、产孢、细胞保护有关的物质。首次发现烟酰胺可能与蝉棒束孢从营养生长转化为生殖生长及产孢有关;同时赤霉素、ulvaline和δ-氨基-γ-酮戊酸可能与蝉棒束孢产孢或孢子成熟有关,尤其值得注意的是蝉棒束孢在培养后期高速合成和大量积累赤霉素,值得深入研究。根据蝉棒束孢的代谢特点,作为药品及保健品开发蝉棒束孢菌丝产品时,培养时间宜在7–11d。     

Role for dopamine in malonate-induced damage in vivo in striatum and in vitro in mesencephalic cultures

Defects in mitochondrial energy metabolism have been implicated in the pathology of several neurodegenerative disorders. In addition, the reactive metabolites generated from the metabolism and oxidation of the neurotransmitter dopamine (DA) are thought to contribute to the damage to neurons of the basal ganglia. We have previously demonstrated that infusions of the metabolic inhibitor malonate into the striata of mice or rats produce degeneration of DA nerve terminals. In the present studies, we demonstrate that an intrastriatal infusion of malonate induces a substantial increase in DA efflux in awake, behaving mice as measured by in vivo microdialysis. Furthermore, pretreatment of mice with tetrabenazine (TBZ) or the TBZ analogue Ro 4-1284 (Ro-4), compounds that reversibly inhibit the vesicular storage of DA, attenuates the malonate-induced DA efflux as well as the damage to DA nerve terminals. Consistent with these findings, the damage to both DA and GABA neurons in mesencephalic cultures by malonate exposure was attenuated by pretreatment with TBZ or Ro-4. Treatment with these compounds did not affect the formation of free radicals or the inhibition of oxidative phosphorylation resulting from malonate exposure alone. Our data suggest that DA plays an important role in the neurotoxicity produced by malonate. These findings provide direct evidence that inhibition of succinate dehydrogenase causes an increase in extracellular DA levels and indicate that bioenergetic defects may contribute to the pathogenesis of chronic neurodegenerative diseases through a mechanism involving DA.     

Scurvy in capybaras bred in captivity in Argentine

In order to determine if the absence of vitamin C in the diet of capybaras (Hydrochoerus hydrochaeris) causes scurvy, a group of seven young individuals were fed food pellets without ascorbic acid, while another group of eight individuals received the same food with 1 g of ascorbic acid per animal per day. Animals in the first group developed signs of scurvy-like gingivitis, breaking of the incisors and death of one animal. Clinical signs appeared between 25 and 104 days from the beginning of the trial in all individuals. Growth rates of individuals deprived of vitamin C was considerably less than those observed in the control group. Deficiency of ascorbic acid had a severe effect on reproduction of another population of captive capybaras. We found that the decrease in ascorbic acid content in the diet affected pregnancy, especially during the first stages. The results obtained suggest that it is necessary to supply a suitable quantity of vitamin C in the diet of this species in captivity.     

Changes in lactate dehydrogenase activity in chicken tissues in hyperthyreosis in ontogenesis

The lactate dehydrogenase activity in reactions of lactate oxidation and synthesis was studied in subfractions of the chicken brain, heart and liver at the embryonal, early postembryonal and adult stages of development after thyroxine administration. It has been shown that during embryogenesis thyroxine predominantly enhanced the rate of lactate oxidation in the mitochondrial tissues. A marked increase in the lactate synthesis was found in cytoplasm of the adult chicken tissues. Specificity of enzyme activity alterations was detected in the chicken brain during ontogenesis after thyroxine administration.     

SSTR5 ablation in islet results in alterations in glucose homeostasis in mice

Somatostatin (SST) peptide is a potent inhibitor of insulin secretion and its effect is mediated via somatostatin receptor 5 (SSTR5) in the endocrine pancreas. To investigate the consequences of gene ablation of SSTR5 in the mouse pancreas, we have generated a mouse model in which the SSTR5 gene was specifically knocked down in the pancreatic beta cells (betaSSTR5Kd) using the Cre-lox system. Immunohistochemistry analysis showed that SSTR5 gene expression was absent in beta cells at three months of age. At the time of gene ablation, betaSSTR5Kd mice demonstrated glucose intolerance with lack of insulin response and significantly reduced serum insulin levels. Insulin tolerance test demonstrated a significant increase of insulin clearance in vivo at the same age. In vitro studies demonstrated an absence of response to SST-28 stimulation in the betaSSTR5Kd mouse islet, which was associated with a significantly reduced SST expression level in betaSSTR5Kd mice pancreata. In addition, betaSSTR5Kd mice had significantly reduced serum glucose levels and increased serum insulin levels at 12 months of age. Glucose tolerance test at an older age also indicated a persistently higher insulin level in betaSSTR5Kd mice. Further studies of betaSSTR5Kd mice had revealed elevated serum C-peptide levels at both 3 and 12 months of age, suggesting that these mice are capable of producing and releasing insulin to the periphery. These results support the hypothesis that SSTR5 plays a pivotal role in the regulation of insulin secretion in the mouse pancreas.