Lipids of Prokaryotic Origin at the Base of Marine Food Webs

Abstract

In particular niches of the marine environment, such as abyssal trenches, icy waters and hot vents, the base of the food web is composed of bacteria and archaea that have developed strategies to survive and thrive under the most extreme conditions. Some of these organisms are considered “extremophiles” and modulate the fatty acid composition of their phospholipids to maintain the adequate fluidity of the cellular membrane under cold/hot temperatures, elevated pressure, high/low salinity and pH. Bacterial cells are even able to produce polyunsaturated fatty acids, contrarily to what was considered until the 1990s, helping the regulation of the membrane fluidity triggered by temperature and pressure and providing protection from oxidative stress. In marine ecosystems, bacteria may either act as a sink of carbon, contribute to nutrient recycling to photo-autotrophs or bacterial organic matter may be transferred to other trophic links in aquatic food webs. The present work aims to provide a comprehensive review on lipid production in bacteria and archaea and to discuss how their lipids, of both heterotrophic and chemoautotrophic origin, contribute to marine food webs.

Rapid adaptation of Rhodococcus erythropolis cells to salt stress by synthesizing polyunsaturated fatty acids

“…5 Variation of the content of PUFA in relation to the zeta potential of the R. erythropolis cells exposed to 1-7.5 % (w/w) NaCl these conditions were about 1 order of magnitude lower than those observed in the present study. Fulco demonstrated that bacilli and mycobacteria could produce dienoic fatty acids by aerobic desaturation of fatty acids (Fulco 1974), but recent studies link the fatty acid composition to the bacterial ecological niche (de Carvalho and Caramujo 2012;de Carvalho and Fernandes 2010;Nichols 2003). As previously mentioned, it is generally accepted that only few bacteria are capable of synthesising PUFAs, whereby most of them are marine bacteria, in particular from cold, deep-sea sediments, fish and water (Hamamoto et al 1995;Yano et al 1998;Yano et al 1997).…”

“…This assumption was derived probably, as pointed out by Okuyama et al (2007), from the fact that the best studied bacterial species in terms of physiology, biochemistry and molecular biology were mesophilic species such as Escherichia coli containing no PUFAs. It is now accepted that long-chain PUFAs, such as EPA, DHA and ARA, are preferentially produced by marine bacteria (de Carvalho and Caramujo 2012;DeLong and Yayanos 1986;Hamamoto et al 1995;Nichols 2003;Russell and Nichols 1999). PUFAs may also easily be decomposed by autoxidation during analytical procedures or by harsh transesterification methods, e.g.…”

Bacteria as food in aquaculture: do they make a difference?

“…However, few bacteria, such as methanotrophic bacteria, are known to produce sterols (Schouten et al 2000;Volkman 2003) and it is accepted that some species do have the capacity to produce eicosapentaenoic acid (20:5x3, EPA), docosahexaenoic acid (22:6x3, DHA) or arachidonic acid (20:4x6, ARA) (Watanabe et al 1997;de Carvalho & Caramujo 2012). The phylogeny and distribution of marine bacteria that do produce n-3 PUFAs has been reviewed by Russell and Nichols (1999) and by Nichols and McMeekin (2002).…”

Marine Biofilms: A Successful Microbial Strategy With Economic Implications

“…Bacteria play important roles in marine environments, including driving biogeochemical cycles (Paerl and Pinckney, 1996;Hawley et al, 2017) and supplying materials and energy to higher trophic levels (Azam et al, 1983;de Carvalho and Caramujo, 2012). The phenotypic plasticity of bacteria is responsible for their success and ubiquity (Brown and Williams, 1985;López-Maury et al, 2008).…”