Fatty acid composition of freshwater heterotrophic flagellates: an experimental study

نویسندگان

  • Aurélie Véra
  • Christian Desvilettes
  • Alexandre Bec
  • Gilles Bourdier
چکیده

The fatty acid compositions of 5 freshwater heterotrophic flagellates were studied using laboratory cultures. The flagellates Bodo saltans, Paraphysomonas vestita, Spumella pudica, Polytoma uvella and Chilomonas paramecium were cultured on Synura medium enriched either with Régilait milk powder (MP medium; Régilait, 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 contents 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 bioconversion 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. paramecium 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 content of these flagellates.

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Study and determination of fatty acid composition of some commercially important freshwater fish

Fatty acid composition of fish is one of the key factors for the evaluation of fish nutritional value and it could be different based on fish species, habitat, nutrition and etc. The aim of the present study was to evaluate the fatty acid composition of five commercially important freshwater fish from the fish market. Studied fish were as follows: Barbell, Luciobarbus pectoralis (Heckel, 1843),...

متن کامل

Free-living Heterotrophic Flagellates from Freshwater Sites in Tasmania (Australia), a Field Survey

In order to contribute to an understanding of the geographic distribution of free-living freshwater flagellates, we have investigated the diversity of heterotrophic flagellates occurring in a number of freshwater sites in Tasmania (Australia). This community of organisms has not previously been studied in Tasmania, and the isolation of the freshwater habitats from like habitats elsewhere in the...

متن کامل

Molecular comparisons of freshwater and marine isolates of the same morphospecies of heterotrophic flagellates.

Heterotrophic flagellates are key components of all ecosystems. Understanding the patterns of biodiversity of these organisms is thus particularly important. Here we analyzed the intraspecific diversity of 10 morphospecies of heterotrophic flagellates comprising representatives of the Apusozoa (2 morphospecies) and Kinetoplastea (8 morphospecies), all belonging to the most common flagellates wi...

متن کامل

Negative consequences of glacial turbidity for the survival of freshwater planktonic heterotrophic flagellates

Heterotrophic (phagotrophic) flagellates are key components of planktonic food webs in freshwater and marine ecosystems because they are the main consumers of bacteria. Although they are ubiquitous in aquatic ecosystems, they were numerically undetectable in turbid glacier-fed lakes. Here we show that glacial particles had negative effects on the survival and growth of heterotrophic flagellates...

متن کامل

Nutritional value of freshwater mesozooplankton assemblages from Hanna Dam Lake, Iran, during a one-year study

Nutritional value of freshwater mesozooplankton, fatty acid (FA) and amino acid (AA) compositions were determined in the middle of each season for a one-year period from May 2009 to February 2010 in Hanna Dam Lake, Isfahan, Iran. FA and AA composition significantly (P < 0.05) varied in relation to the seasonal changes of water quality, phytoplankton and zooplankton community. The content of sat...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2001