A population of giant tailed virus-like particles associated with heterotrophic flagellates in a lake-type reservoir

Aquatic Microbial Ecology

John R. Dolan¹  Markus G. Weinbauer¹  Karel Šimek¹ 

关键词: Viral infection;    Mortality;    Burst size;   

DOI  :  10.3354/ame01769

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: Using transmission electron microscopy (TEM), a population of giant virus-like particles (VLPs) with a head diameter of ca. 405 nm and a flexible ca. 1100 nm long tail was detected in a lake-type reservoir. These giant VLPs were abundant in situ at the start of a survey period (3.3 × 10⁴ particles ml^-1) and increased by 7-fold within 96 h. This VLP population vanished in dialysis bag incubations of 0.8 µm-filtered reservoir water (free of bacterivorous flagellates) but increased markedly in the enhanced bacterivory treatment, i.e. 5 µm filtered water. In the latter, incubation, heterotrophic nanoflagellate (HNF) abundance increased approximately 15-fold during the study. A multiple regression analysis using microbial abundances and grazing rates as parameters indicated that 78% of the variability in the abundance of giant VLPs was explained by HNF abundance and grazing rates. Our data support the hypothesis that this virus population infects flagellates. Observation of a presumptive lysing flagellate cell suggests a viral burst size of 15. Estimations of decay and net production rates from dialysis bag incubations indicate that lysis due to giant viruses could cause between 10 to 60% of the mortality of the total flagellate community and, thus, viruses are potentially a significant factor shaping the population dynamics of flagellates in freshwater.

【 授权许可】

Unknown