Identification and Characterization of Vernalophrys algivore n. g. n. sp. (Rhizaria: Cercozoa: Vampyrellida), a New Algal Predator Isolated from Outdoor Mass Culture of Scenedesmus dimorphus

作者:	Yingchun Gong, Yingchun Gong, David J. Patterson, Yunguang Li, Zixuan Hu, Milton Sommerfeld, Yongsheng Chen, Qiang Hu
通讯作者:	Yingchun Gong, Qiang Hu
摘要:	Microbial contamination is the main cause of loss of biomass yield in microalgal cultures, especially under outdoor environmental conditions. Little is known about the identity of microbial contaminants in outdoor mass algal cultures. In this study, a new genus and species of vampyrellid amoeba, Vernalophrys algivore, is described from cultures of Scenedesmus dimorphus in open raceway ponds and outdoor flat-panel photobioreactors. This vampyrellid amoeba was a significant grazer of Scenedesmus and was frequently associated with a very rapid decline in algal numbers. We report on the morphology, subcellular structure, feeding behavior, molecular phylogeny and life cycle. The new amoeba resembles Leptophrys in the shape of trophozoites and pseudopodia and in the mechanism of feeding (mainly by engulfment). It possesses two distinctive regions in Helix E10_1 (nucleotides 117-119, CAA) and E23_1 (nucleotides 522-523, AG) of the 18S rRNA gene. It did not form a monophyleytic group with Leptophrys in molecular phylogenetic trees. We establish a new genus, Vernalophrys, with the type species Vernalophrys algivore. The occurrence, impact of the amoeba on mass culture of Scenedesmus dimorphus, and means to reduce vampyrellid amoeba contamination in Scenedesmus cultures are addressed. The information obtained from this study will be useful for developing an early warning system and control measures for preventing or treating this contaminant in microalgal mass cultures.
卷:	81
期:	12
页码:	3900-3913
发表时间:	2015-06-04
刊物名称:	Applied and Environmental Microbiology
全文链接:	http://dx.doi.org/http://aem.asm.org/content/early/2015/03/23/AEM.00160-15.abstract