Nikolay A. Latyshev

Effect of habitat on participation of symbionts in formation of the fatty acid pool of fresh-water sponges of Lake Baikal

1. 1. Fatty acid composition of total lipids was studied in 6 species and 2 morphs of fresh-water sponges (Ceractimorpha, Lubomirskiidae) of Lake Baikal. 2. 2. Intracellular microalga and bacterial symbionts were separated from cell homogenate of the sponge Lubomirskia baicalensis in the density gradient of Ficoll 400. An analysis of fatty acids of polar and neutral lipids of microalgae and total lipids of symbiotic bacteria has not detected appreciable amounts of “demospongic” acids either in storage or in structural lipids. This may indicate that biosynthetic centers of normal and “demospongic” acids are separated in symbiotic associations. 3. 3. The amount of polyenoic fatty acid 18:3w3 typical of chloroplast membranes suggests that microalgal contribution to the total pool of fatty acids of the sponge Baicalospongia bacillifera significantly decreased at greater depths, without any rise in the content of branched fatty acids which are characteristic of bacteria.

New Δ5 and Δ4 unsaturated medium- and long-chain fatty acids in the freshwater sponge Baicalospongia bacilifera

Abstract The composition of Δ5(Δ4) unsaturated medium- and long-chain fatty acids (FAs) of the freshwater sponge Baicalospongia bacilifera was selectively determined by means of the analytical iodolactonization reaction and the structures of FAs were identified by gas chromatography-mass spectrometry (GC-MS), spectrophotometry, and particular chemical degradation. The presence of several unusual monoenoic branched-chain FAs iso -15:1 Δ4, anteiso -15:1 Δ4, iso -17:1 Δ4, anteiso -17:1 Δ4, non-methylen interrupted tetraenoic acid 18:4 Δ5,9,12,15 and isomeric eicosapentaenoic acid (IEPA) with a trans double bond (20:5 Δ5 c ,8 c ,11 t ,14 c ,17 c ) was shown.

Fatty acid composition as an indicator of possible sources of nutrition for soft corals of the genus Sinularia (Alcyoniidae)

Fatty acids (FAs) composition of eight zooxanthellate soft corals, Sinularia leptoclados, S. flexibilis, S. aff. deformis, S. loch-modes, S. cf. muralis, S. densa, S. notanda and S. cruciata collected in Van Phong Bay (Vietnam) were studied to identify possible origin of unsaturated FAs. The main FAs were 14 : 0 , 1 6: 0 , 7-Me-16:1n-10, 16:1n-7, 16:2n-7, 18:0, 18:1n-9, 18:4n-3, 20:4n-6, 20:5n-3, 22:6n-3, 24:5n-6 and 24:6n-3. On the average, saturated, monounsaturated, and polyunsaturated FAs (PUFAs) contributed 35 .6, 6. 2 and 54 . 0 % of total coral FAs, respectively. PUFAs of n-6 series predominated in all animals (n-6/n- 3 > 1 .6). The content of 20:4n-6 varied from 10 . 2 to 23 .8%. The main n- 3 PUFA was 18:4n-3 (on the average, 5.4%), the contribution of 20:5n-3 and 22:6n-3, typical PUFAs of marine organisms, was not more than 2 . 4 and 3 . 9 %, respectively. In Sinularia, PUFAs were produced by endosymbiotic dinoflagellates (zooxanthellae) and the coral host tissue, or obtained with food. Zooxanthellae can be considered as the source of C 16 PUFAs and 18:4n-3. The coral host synthesized 18:2n-7, 24:5n-6 and2 4: 6n-3 acids. The low content of 18:1n-7, saturated odd-chain FAs and saturated methyl-branched FAs indicated a negligible contribution of bacteria to total lipids of Sinularia. A comparison of the levels of diatom and dinoflagellate FA markers in coral and plankton lipids showed eukaryotic microalgae to play a secondary role in feeding of Sinularia. The high level of 2 o: 4 n-6 may be considered as an indicator of heterotrophic feeding of Sinularia.

Analgetic effect of docosahexaenoic acid is mediated by modulating the microglia activity in the dorsal root ganglia in a rat model of neuropathic pain

The analgetic activity of docosahexaenoic acid (DHA, 22:6 n-3) was studied using a chronic constriction injury (CCI) model in rats, and the dynamics of iba-1 (+) microglia/macrophages in the dorsal root ganglia (DRG) were characterized. DHA reduced the intensity and duration of neurogenic pain. The application of DHA led to an earlier stabilization of weight bearing in the incapacitance test and prevented the development of cold allodynia and degenerative changes in tissues of the denervated limb. DHA treatment significantly reduced satellite glia reaction and expression of the pro-apoptotic p53 protein in the DRG. Thus, DHAs anti-pain effect may be a result of the modulation of microglia/macrophages activity and the development of neuroprotective effects at the level of the dorsal root ganglia.

Neuron-astrocyte interactions in spinal cord dorsal horn in neuropathic pain development and docosahexaenoic acid therapy

The analgesic activity of docosahexaenoic acid (DHA, 22:6 n-3) was studied using a chronic constriction injury (CCI) rat model. Animals were subcutaneously injected with DHA emulsion at a dose of 4.5mg/kg (125mМ/kg) daily during 2weeks after surgery. We characterized the dynamics of GFAP-positive astrocyte, substance P (SP) and nNOS-positive neurons activity in the spinal cord dorsal horn (SCDH) superficial lamina. We found that DHA treatment decrease the intensity and duration of neurogenic pain syndrome, results in earlier stabilization of weight distribution, prevents the cold allodynia and dystrophic changings in denervated limb tissue. DHA treatment reduced the reactive astrocyte number, decrease SP-immunopositive fibers and nNOS-positive neurons number in the SCDH in neuropathic pain.