Lipid distribution in branching coral Montipora digitata

Abstract

>ABSTRACT: The lipid profile was studied along the branch length, from the top, middle to base portion, of coral Montipora digitata to gain more insight into the physiological significance of lipids in the coral energy budget. The lipids of M. digitata consisted of seven major lipid classes: polar lipid, sterol, free fatty acid, unknown lipids 1 and 2, triacylglycerol (TG), and wax ester. The concentration of storage lipids, TG, and wax ester showed a top–base gradient along the length, whereas the levels of free fatty acid and unknown lipids showed a base–top gradient. The proportions of polar lipid and sterol in the top portion of the branch were slightly higher than those in the base portion. This observation appeared to be compatible with the view that the increased energy expenditure for proliferation enhanced the mobilization of the storage fuel lipids of wax ester and TG rather than the structure lipids of polar lipids and sterols at the top portion of the branch. Compositions of fatty acid also showed a length‐wise diversity. The top portion had a lower proportion of palmitic acid (16 : 0) in all lipid classes of fatty acid ester, suggesting that this fatty acid was preferentially mobilized at the top portion, probably for the growth of coral cells.

Effect of light and feeding on the fatty acid and sterol composition of zooxanthellae and host tissue isolated from the scleractinian coral Turbinaria reniformis

“…The energy obtained from feeding was preferentially directed toward an increase in chlorophyll concentrations as well as in skeletal growth (Table 1). We can hypothesize that feeding at high light level also increased lipid concentrations, but that skeletal and tissue growth rapidly induced lipid consumption (mainly sterols and n-alcohols), as has already been demonstrated with growing cells (Ward 1995;Oku et al 2002). The response of T. reniformis to feeding in the present study was similar to the one observed in Stylophora pistillata maintained under the same light level (300 mmol photons m 22 s 21 ), for which feeding enhanced all physiological parameters and especially skeletal growth (Houlbrèque et al 2003(Houlbrèque et al , 2004.…”

“…Both autotrophy and heterotrophy supply corals with major compounds, such as glycerol and other lipids (Crossland et al 1980;Grottoli et al 2006), which play an essential role in coral metabolism at all levels. Lipids are important energy reserves, mainly stored in the animal tissue as wax esters and triglycerides (Muscatine and Cernichiari 1969;Oku et al 2002;Grottoli et al 2004), or in the membranes as sterols and polyunsaturated fatty acids (PUFA; Tchernov et al 2004). These reserves are, for example, used in the reproduction process (Ward 1995) or are oxidized to generate energy for survival during bleaching events (Yamashiro et al 2005;Grottoli et al 2006;Rodrigues and Grottoli 2007).…”

Lipids and nitrogen isotopes of two deep-water corals from the North-East Atlantic: initial results and implications for their nutrition

“…Such fatty acids were not detected in this study, but the variability in proportions of PUFAs (and MUFAs) of both corals may also be related to environmental, physiological and/or biochemical factors. For example, Oku et al (2002) showed that the polyps of the shallow-water branching coral Montipora digitata have different lipid distributions according to their position in the branch. Clearly much more detailed work is required (see also Mancini et al 1999).…”

Increased susceptibility of algal symbionts to photo-inhibition resulting from the perturbation of coral gastrodermal membrane trafficking

“…Various light harvesting efficiencies in different regions of the coral colony could lead to dynamic membrane trafficking and lipid metabolism of SGCs in situ. This could lead to the documented lipid profile differences measured across branching coral colonies [31]. …”

“…To examine whether there is interaction between the gastrodermal plasma membrane and Symbiodinium photosynthesis in SGCs, the gastrodermal plasma membrane fluidity was altered by specifically removing plasma membrane cholesterol using methyl--cyclodextrin (MCD) and then examined to determine whether photosynthesis was affected in these cholesterol-depleted SGCs. Cholesterol is abundant in cnidarian species, including sea anemones and various corals [31,32]. The ability of MCD to remove plasma membrane cholesterol was first assessed by lipid analysis using thin-layer chromatography in both SGCs and cultured Symbiodinium (Figure 4).…”