The Influence of Bioactive Oxylipins from Marine Diatoms on Invertebrate Reproduction and Development

Abstract

Diatoms are one of the main primary producers in aquatic ecosystems and occupy a vital link in the transfer of photosynthetically-fixed carbon through aquatic food webs. Diatoms produce an array of biologically-active metabolites, many of which have been attributed as a form of chemical defence and may offer potential as candidate marine drugs. Of considerable interest are molecules belonging to the oxylipin family which are broadly disruptive to reproductive and developmental processes. The range of reproductive impacts includes; oocyte maturation; sperm motility; fertilization; embryogenesis and larval competence. Much of the observed bioactivity may be ascribed to disruption of intracellular calcium signalling, induction of cytoskeletal instability and promotion of apoptotic pathways. From an ecological perspective, the primary interest in diatom-oxylipins is in relation to the potential impact on energy flow in planktonic systems whereby the reproductive success of copepods (the main grazers of diatoms) is compromised. Much data exists providing evidence for and against diatom reproductive effects; however detailed knowledge of the physiological and molecular processes involved remains poor. This paper provides a review of the current state of knowledge of the mechanistic impacts of diatom-oxylipins on marine invertebrate reproduction and development.

Exploring Valuable Lipids in Diatoms

“…Studies on bioactive aldehydes have showed that these compounds may inhibit the growth of different marine invertebrates such as diatom predators and induce different responses in marine ecosystem (Caldwell, 2009;Lauritano et al, 2016). This property may explain the dynamics behind some blooms and also explain why oxylipin profiles can be used as an additional taxonomic identification tool, providing a functional feature to species characterization and morphological traits.…”

“…d (Volkman et al, 1998;Viegelmann et al, 2014). e (Paul and Fenical, 1986;Nappez et al, 1996;Girona et al, 1997;Caldwell, 2009;Lauritano et al, 2016).…”

Lipids in Marine Ecosystems

“…Unsaturated fatty acid oxidative products, oxylipins [46], are cytotoxic for bacteria, fungi, algae, molluscs, crustaceans, and echinoderms [47], suppressing growth and reproduction [48][49][50]. Oxylipin production in diatoms is wound-activated as would occur during predation and affects population dynamics of copepods [50].…”

“…Reactions with membranes are one of the most prevalent mechanisms of cellular injury and comparisons in warm and cold environments are particularly interesting because of differences in oxygen solubility and conductance in tissues [43] as well as in membrane unsaturation and rates of reactive oxygen species production and lipid peroxidation [45]. Unsaturated fatty acid oxidative products, oxylipins [46], are cytotoxic for bacteria, fungi, algae, molluscs, crustaceans, and echinoderms [47], suppressing growth and reproduction [48][49][50]. Oxylipin production in diatoms is wound-activated as would occur during predation and affects population dynamics of copepods [50].…”

Characteristics of the phytoplankton community and bioaccumulation of heavy metals during algal blooms in Xiangjiang River (Hunan, China)

“…Diatoms are one of the main primary producers in aquatic ecosystems. They are considered to be passive participants in energy transfer in the food webs, being heavily grazed by their predators and exhibiting little or no anti-grazing capacity [26]. A number of diatom species produce the potent neurotoxin domoic acid, including Pseudonitzschia, Nitzschia, and Amphora [10].…”