Surface characteristics of the entomopathogenic fungus Beauveria (Cordyceps) bassiana
Surface characteristics of the entomopathogenic fungus Beauveria (Cordyceps) bassiana
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DOI：
10.1099/mic.0.2007/008524-0
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发表时间：
2007-10-01
期刊：
影响因子：
2.8
通讯作者：
Keyhani, Nemat O.
中科院分区：
文献类型：
--
作者：
Holder, Diane J.;Kirkland, Brett H.;Keyhani, Nemat O.
球孢白僵菌（Beauveria bassiana）单细胞繁殖体的表面特征有显著差异。原子力显微镜（AFM）显示，在离体孢子和浸没孢子中，气生孢子中存在束状或束状结构。使用放置在细胞层上的极性和极性测试液体进行接触角测量，用于计算细胞类型与表面相互作用的表面张力值和自由能。这些分析表明，气生孢子的细胞表面是疏水的，而胚孢子和浸没孢子的细胞表面是亲水的。在pH值为3 ~ 9的条件下，16天生的气生分生孢子细胞表面静电电荷分布的Zeta电位变化范围为+22 ~ -30 mV，而浸没分生孢子细胞表面净电荷变化范围为+ 10 ~ -13 mV，在相同的pH值范围内，胚孢子细胞表面静电电荷变化范围为+4 ~ -4 mV。利用微生物对烃类的黏附（MATH）测定其疏水性表明，气生分生孢子的表面为疏水性，而胚孢子的表面为亲水性，而浸没分生孢子的表面特征介于疏水性和亲水性之间。用烟草芽虫（Heliothis virescens）幼虫进行的昆虫病理学分析显示，局部应用和血凝剂注射的真菌细胞在气生分生孢子、离体芽生孢子和浸没分生孢子中具有一定的毒力差异。
Marked differences in surface characteristics were observed among three types of single-cell propagules produced by the entomopathogenic fungus Beauveria bassiana. Atomic force microscopy (AFM) revealed the presence of bundles or fascicles in aerial conidia absent from in vitro blastospores and submerged conidia. Contact angle measurements using polar and apolar test liquids placed on cell layers were used to calculate surface tension values and the free energies of interaction of the cell types with surfaces. These analyses indicated that the cell surfaces of aerial conidia were hydrophobic, whereas those of blastospores and submerged conidia were hydrophilic. Zeta potential determinations of the electrostatic charge distribution across the surface of the cells varied from +22 to -30 mV for 1 6-day aerial conidia at pH values ranging from 3 to 9, while the net surface charge ranged from + 10 to -13 mV for submerged conidia, with much less variation observed for blastospores, +4 to -4 mV, over the same pH range. Measurements of hydrophobicity using microbial adhesion to hydrocarbons (MATH) indicated that the surfaces of aerial conidia were hydrophobic, and those of blastospores hydrophilic, whereas submerged conidia displayed cell surface characteristics on the borderline between hydrophobic and hydrophilic. Insect pathology assays using tobacco budworm (Heliothis virescens) larvae revealed some variation in virulence among aerial conidia, in vitro blastospores and submerged conidia, using both topical application and haemocoel injection of the fungal cells.