Species-specific patterns in the vulnerability of ­carbon-starved bacteria to protist grazing

Aquatic Microbial Ecology

Diane McDougald¹  Ruth Anderson¹  Klaus Jürgens¹  Staffan Kjelleberg¹ 

关键词: Grazing vulnerability;    Carbon ­starvation;    Growth rate;    Protist;    Bacteria;   

DOI  :  10.3354/ame01518

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: Many heterotrophic bacteria possess adaptations for prolonged survival under carbon and energy limitation, generally involving a reduction in cell size and an increased resistance to environmental stress factors. In order to reveal whether carbon-starved bacteria also become less vulnerable to ­protist grazing, we compared the growth of a bacterivorous nanoflagellate, Cafeteria roenbergensis, on different physiological states of 3 bacterial strains with well-studied starvation responses (Vibrio vulnificus, Photobacterium angustum and Sphingopyxis alaskensis). Protists achieved high growth rates on all 3 bacterial strains when they were provided in a non-starved state. However, for carbon-starved bacteria, pronounced differences in the re­sponse of the flagellates were observed. P. angustum provided similar protist growth for an equal biomass of non-starved and starved cultures, indicating no change in food quality or grazing resistance for carbon-starved cells, despite smaller cell size. In contrast, starved V. vulnificus did not support protist growth, even resulting in a strong decrease in flagellate numbers at most concentrations tested; and starved S. alaskensis provided only reduced growth rates. Our results demonstrate that (1) feeding on bacteria of smaller cell size does not necessarily impose energy constraints on a flagellate grazer, and (2) a pronounced species-specific variability exists in the susceptibility of carbon-starved bacteria to protist grazing.

【 授权许可】

Unknown