Fatty acid composition of freshwater heterotrophic flagellates: an experimental study
Fatty acid composition of freshwater heterotrophic flagellates: an experimental study
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淡水异养鞭毛虫的脂肪酸组成：实验研究
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发表时间：
2001
期刊：
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通讯作者：
G. Bourdier
中科院分区：
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作者：
A. Véra;C. Desvilettes;A. Bec;G. Bourdier
采用实验室培养的方法，对5种淡水异养鞭毛虫的脂肪酸组成进行了研究。在富含Regilait奶粉（MP培养基; Regilait，St Martin Roche，法国）或富含Tabimin干鱼食（DFF培养基; Tetra，Melle，法国）的Synura培养基上培养鞭毛虫Bodo saltans、体毛副单胞菌、Spumella pudica、Polytoma uvella和Chilomonasparamecium。还分析了培养基中存在的细菌。发现富集底物对生物体的脂肪酸谱有显著影响。例如，在MP培养基上生长的鞭毛虫的特征是多不饱和脂肪酸（PUFA）含量很低，占总脂肪酸的1.28 - 5.50%，而在DFF培养基上生长的鞭毛虫含有高达13.20%的PUFA。无论研究的物种，占主导地位的PUFA是（n-6）系列。原生动物中存在支链的非偶数脂肪酸和18：1（n-7），这反映了在摄食性物种（如B）中可以理解的强烈的食菌活性。saltans、P. vestita和S. pudica，但在C.草履虫和P. uvella，因为这些物种已被描述为嗜热的。在这项研究中的异养鞭毛虫似乎有不同的，但相当有限的，PUFA的生物合成和生物转化的能力，这是部分相关的物理化学条件的文化（温度和溶解氧）和生物体的系统发育关系。种含有一个leucoplast或残留的质体复制在一个非常衰减的方式属于其分类组的自养鞭毛虫的特征PUFA配置文件。这主要是C的情况。paramecium和P. uvella。最后，我们的研究结果表明，在自然环境中，pico-tonic猎物的PUFA含量和溶解有机物的PUFA含量是影响这些鞭毛虫PUFA含量的主要因素。
The fatty acid compositions of 5 freshwater heterotrophic flagellates were studied using laboratory cultures. The flagellates Bodo saltans, Paraphysomonas vestita, Spumella pudica, Poly- toma uvella and Chilomonas paramecium were cultured on Synura medium enriched either with Regilait milk powder (MP medium; Regilait, St Martin Roche, France) or with Tabimin dry fish food (DFF medium; Tetra, Melle, France). The bacteria present in the culture media were also analyzed. The enrichment substrate was found to have a pronounced influence on the fatty acid profiles of the organisms. For example, flagellates grown on the MP medium were characterized by very low con- tents of polyunsaturated fatty acids (PUFA; 1.28 to 5.50% of total fatty acids), whereas those grown on DFF medium contained up to 13.20% PUFA. Irrespective of the species studied, the dominant PUFA were those of the (n-6) series. The presence of branched uneven-numbered fatty acids and of 18:1(n-7) within the protozoans reflects an intensive bacterivorous activity that is understandable in phagotrophic species such as B. saltans, P. vestita and S. pudica but is debatable in C. paramecium and P. uvella, as these species have been described as osmotrophic. The heterotrophic flagellates in this study seemed to have varying, but rather limited, capacities of PUFA biosynthesis and biocon- version that were partly related to the physicochemical conditions in the cultures (temperature and dissolved oxygen) and to the phylogenetic relations of the organisms. Species containing a leucoplast or a residual plastid reproduced in a very attenuated manner the characteristic PUFA profiles of autotrophic flagellates belonging to their taxonomic group. This was mainly the case for C. parame- cium and P. uvella. Finally, our results suggest that in the natural environment, the PUFA contents of picoplanktonic prey and of dissolved organic matter are the main factors influencing the PUFA con- tent of these flagellates.