The lipids of slugs and snails: evolution, diet and biosynthesis

Toxicity evaluation of neonicotinoids to earthworm (Eisenia fetida) behaviors by a novel locomotion tracking assay

Pesticides are substances used for controlling, preventing, and repelling pests in agriculture. Among them, neonicotinoids have become the fastest-growing class of insecticides because of their efficiency in targeting pests. They work by strongly binding to nicotinic acetylcholine receptors (nAChRs) in the central nervous system of insects, leading to receptor blockage, paralysis, and death. Despite their selectivity for insects, these substances may be hazardous to non-target creatures, including earthworms. Although earthworms may be invasive in some regions like north America, they contribute to the development of soil structure, water management, nutrient cycling, pollution remediation, and cultural services, positively impacting the environment, particularly in the soil ecosystem. Thus, this study aimed to develop a novel earthworm behavior assay since behavior is a sensitive marker for toxicity assay, and demonstrated its application in evaluating the toxicity of various neonicotinoids. Here, we exposed Eisenia fetida to 1 and 10 ppb of eight neonicotinoids (acetamiprid, clothianidin, dinotefuran, imidacloprid, nitenpyram pestanal, thiacloprid, thiametoxam, and sulfoxaflor) for 3 days to observe their behavior toxicities. Overall, all of the neonicotinoids decreased their locomotion, showed by a reduction of average speed by 24.94-68.63% and increment in freezing time movement ratio by 1.51-4.25 times, and altered their movement orientation and complexity, indicated by the decrement in the fractal dimension value by 24-70%. Moreover, some of the neonicotinoids, which were acetamiprid, dinotefuran, imidacloprid, nitenpyram, and sulfoxaflor, could even alter their exploratory behaviors, which was shown by the increment in the time spent in the center area value by 6.94-12.99 times. Furthermore, based on the PCA and heatmap clustering results, thiametoxam was found as the neonicotinoid that possessed the least pronounced behavior toxicity effects among the tested pesticides since these neonicotinoid-treated groups in both concentrations were grouped in the same major cluster with the control group. Finally, molecular docking was also conducted to examine neonicotinoids' possible binding mechanism to Acetylcholine Binding Protein (AChBP), which is responsible for neurotransmission. The molecular docking result confirmed that each of the neonicotinoids has a relatively high binding energy with AChBP, with the lowest binding energy was possessed by thiametoxam, which consistent with its relatively low behavior toxicities. Thus, these molecular docking results might hint at the possible mechanism behind the observed behavior alterations. To sum up, the present study demonstrated that all of the neonicotinoids altered the earthworm behaviors which might be due to their ability to bind with some specific neurotransmitters and the current findings give insights into the toxicities of neonicotinoids to the environment, especially animals in a soil ecosystem.

Effects of temperature and combinational exposures on lipid metabolism in aquatic invertebrates

Studies of changes in fatty acids in response to environmental temperature changes have been conducted in many species, particularly mammals. However, few studies have considered aquatic invertebrates, even though they are particularly vulnerable to changes in environmental temperature. In this review, we summarize the process by which animals synthesize common fatty acids and point out differences between the fatty acid profiles of vertebrates and those of aquatic invertebrates. Unlike vertebrates, some aquatic invertebrates can directly synthesize polyunsaturated fatty acids (PUFAs), which can be used to respond to temperature changes. Various studies have shown that aquatic invertebrates increase the degree of saturation in their fatty acids through an increase in saturated fatty acid production or a decrease in PUFAs as the temperature increases. In addition, we summarize recent studies that have examined the complex effects of temperature and combinational stressors to determine whether the degree of saturation in aquatic invertebrates is influenced by other factors. The combined effects of carbon dioxide partial pressure, food quality, starvation, salinity, and chemical exposures have been confirmed, and fatty acid profile changes in response to high temperature were greater than those from combinational stressors.

Resistance of Biomphalaria alexandrina to Schistosoma mansoni and Bulinus truncatus to Schistosoma haematobium Correlates with Unsaturated Fatty Acid Levels in the Snail Soft Tissue

Only a fraction of the Biomphalaria and Bulinus snail community shows patent infection with schistosomes despite continuous exposure to the parasite, indicating that a substantial proportion of snails may resist infection. Accordingly, exterminating the schistosome intermediate snail hosts in transmission foci in habitats that may extend to kilometres is cost-prohibitive and damaging to the ecological equilibrium and quality of water and may be superfluous. It may be more cost effective with risk less ecological damage to focus on discovering the parameters governing snail susceptibility and resistance to schistosome infection. Therefore, laboratory bred Biomphalaria alexandrina and Bulinus truncatus snails were exposed to miracidia of laboratory-maintained Schistosoma mansoni and S. haematobium, respectively. Snails were examined for presence or lack of infection association with soft tissue and hemolymph content of proteins, cholesterol, and triglycerides, evaluated using standard biochemical techniques and palmitic, oleic, linoleic, and arachidonic acid, assayed by ultraperformance liquid chromatography-tandem mass spectrometry. Successful schistosome infection of B. alexandrina and B. truncatus consistently and reproducibly correlated with snails showing highly significant (up to P < 0.0001) decrease in soft tissue and hemolymph content of the monounsaturated fatty acid, oleic acid, and the polyunsaturated fatty acids, linoleic, and arachidonic acids as compared to naïve snails. Snails that resisted twice infection had soft tissue content of oleic, linoleic, and arachidonic acid similar to naïve counterparts. High levels of soft tissue and hemolymph oleic, linoleic, and arachidonic acid content appear to interfere with schistosome development in snails. Diet manipulation directed to eliciting excessive increase of polyunsaturated fatty acids in snails may protect them from infection and interrupt disease transmission in a simple and effective manner.

Fatty Acid Profile in Fat Obtained from Edible Part of Land Snails Harvested in Poland

Introduction

The objective was to determine the content of fatty acids in edible snail fat by snail species, collection site, and processing stage.

Material and Methods

The research material comprised 180 edible fat samples from the three genera of edible snails collected in Poland: free-living Helix pomatia (HP) and two cultivated Cornu subspecies: C. aspersa maxima (CAM) and C. aspersum aspersum (CAA). All snails came from the Greater Poland and Lower Silesian Provinces: HP from their natural habitat and CAM and CAA from heliciculture farms. The studies focused on the raw meat, cooked meat, and frozen meat processing stages. Fatty acid (FA) profiles were determined by the gas chromatography method.

Results

Helix pomatia fat showed a higher saturated fatty acid (SFA) content, whereas the fat of Cornu genus snails had a higher unsaturated fatty acid (UFA) component, i.e. monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA). Thermal processing of snail meat increased all the determined SFA and decreased all the PUFA values, and increased the content of C18:1, C20:1, and C22:1 acids in the MUFA group. The material collection site had limited impact on FA content as differences were noted only in levels of C18:1, C18:2 n6, and C20:5. The differences pertained only to the fat of farmed snails of the Cornu genus.

Conclusion

Due to the high content of UFA and a favourable ratio of n6:n3 acids and PUFA:SFA, snail fat can be regarded as nutritionally valuable.

Polyunsaturated fatty acids from Phyllocaulis boraceiensis mucus block the replication of influenza virus

Influenza viruses cause worldwide outbreaks and pandemics in humans and animals every year with considerable morbidity and mortality. The molecular diversity of secondary metabolites extracted from mollusks is a good alternative for the discovery of novel bioactive compounds with unique structures and diverse biological activities. Phyllocaulis boraceiensis is a hermaphroditic slug that exudes mucus, in which was detected hydroxy polyunsaturated fatty acids that exhibited potent antiviral activity against measles virus. The objective of this study was to evaluate this property against Influenza viruses. Cell viability and toxicity of the mucus were evaluated on Madin-Darby canine kidney (MDCK) cells by MTT assay. Antiviral activity from mucus against influenza viruses was carried out by determination of the virus infection dose and by immunofluorescence assays. The crude mucus and its fractions exhibited low cytotoxicity on MDCK cells. A significant inhibition of viral replication, reduced by the order of eight times, was observed in influenza-induced cytopathic effect. In immunofluorescence assay was observed a decrease of more than 80% of the viral load on infected MDCK cell treated with mucus and its fractions. The viral glycoproteins hemagglutinin and neuraminidase located on the surface of the virus are crucial for the replications and infectivity of the influenza virus. Some authors demonstrated that lipids, such as, polyunsaturated fatty acids exhibited multiple roles in antiviral innate and adaptive responses, control of inflammation, and in the development of antiviral therapeutics. As corroborated by other studies, hydroxy polyunsaturated fatty acids interfered with the binding of influenza virus on host cell receptor and reduced viral titers. The results obtained indicated that polyunsaturated fatty acids from P. boraceiensis crude mucus and fractions 39 exerted antiviral activity against influenza virus.

Changes in fatty acid metabolism induced by varied micro-supplementation with zinc in snails Helix pomatia (Gastropoda Pulmonata)

We analyzed the changes in the profile of fatty acids (FA) in the foot tissues and hepatopancreas (HP) of snails Helix pomatia exposed to five microdoses of zinc (0.1, 0.25, 0.5, 0.75, or 1mg/l) administered in the form of a pure salt solution and in the form of EDTA and lysine chelates. Selection from a pool of 56 fatty acids analyzed in snail tissues yielded a set of 12 biomarker acids undergoing significant changes in contact with toxic substances. The selection criteria included the greatest percentage among the FA profile and their significant role in physiological processes. The proposed palette of acids of the biomarker FAs comprised C16:0; C18:0; C23:0; C18:1 n-9; C20:1 n-9; C18:2 n-6; C18:3 n-3; C20:2; C20:4 n-6; C20:5 n-3; C22:4 n-6; and C22:5 n-3, and saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), and polyunsaturated fatty acids (PUFAs), determined separately in the foot tissues and hepatopancreas. The significant (p=0.01) influence of the dose as well as the source of the zinc on its' concentration in the tissues and on changes in the fatty acid profiles. Among the three zinc forms administered to the snails, the highest bioaccumulation of zinc in both tissues was noted in the group receiving the Zn-EDTA chelate. The content of PUFAs increased as the supplementation with zinc increased up to 0.75mg/l, but at 1mg/l, the share of these FAs began to decrease. This trend was observed in both analyzed tissue types - foot and hepatopancreas. The dose of 1mg Zn/l might be considered as a threshold dose above which the saturation of FAs increases. The results proved that determination of FA profile in snails can be used in ecotoxicological research as a reliable test of the effect of trace doses of stressors. The micro-supplementation of the mollusks diet with zinc is an example of a non-routine approach to issues connected with both diet and toxicology.

Biosynthesis of polyunsaturated fatty acids in marine invertebrates: recent advances in molecular mechanisms

Virtually all polyunsaturated fatty acids (PUFA) originate from primary producers but can be modified by bioconversions as they pass up the food chain in a process termed trophic upgrading. Therefore, although the main primary producers of PUFA in the marine environment are microalgae, higher trophic levels have metabolic pathways that can produce novel and unique PUFA. However, little is known about the pathways of PUFA biosynthesis and metabolism in the levels between primary producers and fish that are largely filled by invertebrates. It has become increasingly apparent that, in addition to trophic upgrading, de novo synthesis of PUFA is possible in some lower animals. The unequivocal identification of PUFA biosynthetic pathways in many invertebrates is complicated by the presence of other organisms within them. These organisms include bacteria and algae with PUFA biosynthesis pathways, and range from intestinal flora to symbiotic relationships that can involve PUFA translocation to host organisms. This emphasizes the importance of studying biosynthetic pathways at a molecular level, and the continual expansion of genomic resources and advances in molecular analysis is facilitating this. The present paper highlights recent research into the molecular and biochemical mechanisms of PUFA biosynthesis in marine invertebrates, particularly focusing on cephalopod molluscs.

Composition of body storage compounds influences egg quality and reproductive investment in the land snail Cornu aspersum

In invertebrates, resources available for growth and reproduction might influence the composition of body stores and subsequently nutrient allocation to eggs, thereby adjusting energy investment in reproduction. We investigated in the land snail Cornu aspersum (Müller, 1774) the efficiency of growth and the main storage compounds in the body and in eggs with respect to lipid content in food (5.5% versus 2.5%). The high body dry mass density of snails fed on lipid-rich diet underlined the high storage capacity of neutral lipids acquired during growth (high growth efficiency) without changing energy content because of the prevailing carbohydrate storage compounds. Reproductive investment was lower in these snails, and maternal effects decreased clutch size. Triglyceride allocation to eggs might enhance survival probability of offspring and therefore compensate for smaller clutch size. Snails fed on lipid-poor diet maximized their investment in clutch size whatever the amount of body stores, and allocated a higher amount of cholesterol to eggs. Cholesterol could be essential for embryo growth, as it ensures membrane functioning. In conclusion, the availability of resources can differentially affect nutrient allocation and energy investment in reproduction. Thus, the investigation of physiological processes becomes essential to understand population dynamics in fluctuating or changing habitats.

Identification of a Δ5-like fatty acyl desaturase from the cephalopod Octopus vulgaris (Cuvier 1797) involved in the biosynthesis of essential fatty acids

Long-chain polyunsaturated fatty acids (LC-PUFA) have been identified as essential compounds for common octopus (Octopus vulgaris), but precise dietary requirements have not been determined due, in part, to the inherent difficulties of performing feeding trials on paralarvae. Our objective is to establish the essential fatty acid (EFA) requirements for paralarval stages of the common octopus through characterisation of the enzymes of endogenous LC-PUFA biosynthetic pathways. In this study, we isolated a cDNA with high homology to fatty acyl desaturases (Fad). Functional characterisation in recombinant yeast showed that the octopus Fad exhibited Δ5-desaturation activity towards saturated and polyunsaturated fatty acyl substrates. Thus, it efficiently converted the yeast's endogenous 16:0 and 18:0 to 16:1n-11 and 18:1n-13, respectively, and desaturated exogenously added PUFA substrates 20:4n-3 and 20:3n-6 to 20:5n-3 (EPA) and 20:4n-6 (ARA), respectively. Although the Δ5 Fad enables common octopus to produce EPA and ARA, the low availability of its adequate substrates 20:4n-3 and 20:3n-6, either in the diet or by limited endogenous synthesis from C(18) PUFA, might indicate that EPA and ARA are indeed EFA for this species. Interestingly, the octopus Δ5 Fad can also participate in the biosynthesis of non-methylene-interrupted FA, PUFA that are generally uncommon in vertebrates but have been found previously in marine invertebrates, including molluscs, and now also confirmed to be present in specific tissues of common octopus.

Lipids analysis in hemolymph of African giant Achatina fulica (Bowdich, 1822) exposed to different photoperiods

The influence of different photophases (0, 6, 12, 18 and 24 hours) on the triglycerides and total cholesterol contents in the hemolymph of A. fulica was evaluated, since there is no information in the literature about the influence of this factor on lipids metabolism in mollusks. After 2 and 4 weeks of exposure the snails were dissected. The cholesterol content at the 2nd and 4th weeks post exposure only varied significantly in the groups exposed at 24 hours and 0 hour of photophase, respectively. Probably, such increase may be a result of a rise in cholesterol biosynthesis and/or remodelling of cell membranes. There were no significant differences among the content of triglycerides in the snails exposed to 6, 12, 18 and 24 hours of photophase during two weeks. The snails exposed to intermediate photophase (6 and 12 hours) had the triglycerides content increased, ranging over values near to those observed in the group exposed to 0 hour. Results showed that triglycerides metabolism in A. fulica are more influenced by photoperiod than cholesterol metabolism. A negative relation is maintained between the triglycerides content in the hemolymph and the different photophases, with lower mobilisation of triglycerides under shorter photophases.

Comparison of transfer and effects of Cd on rats exposed in a short experimental snail-rat food chain or to CdCl2 dosed food

Transfer and toxic effects of two cadmium (Cd) forms, inorganic (CdCl2 dosed rat food) or organic (contaminated snail-based rat food) were studied in Wistar rat. Cd concentrations in rat food were 0 and 2.5 microg Cd g(-1) for both inorganic and organic forms and a high concentration of 100 microg Cd g(-1) was also tested for the inorganic form. Rats were exposed for four weeks to contaminated food. Both forms of Cd were bioavailable to rats, with a percentage of transfer from food to rats of around 1% for all contaminated groups. Cd concentrations in rat tissues increased with increasing Cd concentrations in the food. Rats fed with organic form of Cd accumulated significantly more Cd in the main organ for Cd toxicity, the kidney, than those eating the inorganic form. Survival was not affected for any rat group but a decrease in growth and food consumption was observed for the inorganic form. As a defence system against Cd toxicity, rats increased their metallothionein (MT) synthesis at the highest Cd concentration in the target organs (kidney, liver and small intestine) and even did the same at low Cd concentrations (2.5 microg Cd g(-1)) in the kidney. At this low Cd concentration, MT induction was lower in the small intestine of rats ingesting organic Cd than those ingesting inorganic Cd. Bioavailability of organic and inorganic forms of Cd was similar, but subsequent Cd distribution within organs was different. This quantification of the trophic transfer of both inorganic and organic forms of a toxicant is a basis for a better assessment of the fate and effects of chemicals in food webs.

Effects of diet and metamorphosis upon the sterol composition of the butterfly Morpho peleides

Whole body sterol metabolism in insects has seldom been studied. We were able to design an appropriate study at a butterfly farm in Belize. We collected six larvas of butterfly (Morpho peleides), their food (leaves of Pterocarpus bayessii), and their excretions. In addition, six adult butterflies were collected. The sterols of the diet, the larva, and adult butterfly were analyzed by gas-liquid chromatography. The structures of these sterols were identified by digitonin precipitation, GC-MS, and NMR. Four sterols (cholesterol, campesterol, stigmasterol, and sitosterol) and a sterol mixture were found in the food, the body, and the excreta of the larva. The tissue sterol content of the larva was 326 microg. They consumed 276 microg of sterols per day. Their excretion was 185 microg per day as sterols. The total tissue sterol contents of the larva and butterfly were similar, but they had different sterol compositions, which indicated interconversion of sterols during development. There was a progressive increase in the cholesterol content from larva to butterfly and a decrease in the content of sitosterol and other plant sterols, which were likely converted to cholesterol. Our data indicated an active sterol metabolism in butterfly larva. Diet played an important role in determining its sterol composition. During metamorphosis, there was an interconversion of sterols. This is the first paper documenting the fecal sterol excretion in insects as related to dietary intakes.

The predominance of polyunsaturated fatty acids in the butterfly Morpho peleides before and after metamorphosis

We hypothesized that the polyunsaturated fatty acids of the butterfly were probably derived from the diet and that there might be a great loss of body fat during metamorphosis. To substantiate these hypotheses, we analyzed the fatty acid composition and content of the diet, the larva, and the butterfly Morpho peleides. Both the diet and the tissues of the larva and butterfly had a high concentration of polyunsaturated fatty acids. In the diet, linolenic acid accounted for 19% and linoleic acid for 8% of total fatty acids. In the larva, almost 60% of the total fatty acids were polyunsaturated: linolenic acid predominated at 42% of total fatty acids, and linoleic acid was at 17%. In the butterfly, linolenic acid represented 36% and linoleic acid represented 11% of total fatty acids. The larva had a much higher total fatty acid content than the butterfly (20.2 vs. 6.9 mg). Our data indicate that the transformation from larva to butterfly during metamorphosis drastically decreased the total fatty acid content. There was bioenhancement of polyunsaturated fatty acids from the diet to the larva and butterfly. This polyunsaturation of membranes may have functional importance in providing membrane fluidity useful in flight.

Functional expression of a Delta12 fatty acid desaturase gene from spinach in transgenic pigs

Linoleic acid (18:2n-6) and alpha-linolenic acid (18:3n-3) are polyunsaturated fatty acids that are essential for mammalian nutrition, because mammals lack the desaturases required for synthesis of Delta12 (n-6) and n-3 fatty acids. Many plants can synthesize these fatty acids and, therefore, to examine the effects of a plant desaturase in mammals, we generated transgenic pigs that carried the fatty acid desaturation 2 gene for a Delta12 fatty acid desaturase from spinach. Levels of linoleic acid (18:2n-6) in adipocytes that had differentiated in vitro from cells derived from the transgenic pigs were approximately 10 times higher than those from wild-type pigs. In addition, the white adipose tissue of transgenic pigs contained approximately 20% more linoleic acid (18:2n-6) than that of wild-type pigs. These results demonstrate the functional expression of a plant gene for a fatty acid desaturase in mammals, opening up the possibility of modifying the fatty acid composition of products from domestic animals by transgenic technology, using plant genes for fatty acid desaturases.

Utilisation of lipids, protein, ions and energy during embryonic development of Australian oviparous skinks in the genus Lampropholis

The contents of eggs and neonates of the Australian skinks, Lampropholis guichenoti and L. delicata, are described and compared to allow interpretation of nutrient utilisation by the developing embryo. Even though the females are the same size, L. guichenoti lay smaller clutches of larger eggs (egg contents=41.6+/-1.2 mg dry mass) than L. delicata (26.6+/-2.8 mg). The energy density is the same for eggs (30.5+/-0.9 J/g ash-free dry mass for L. guichenoti and 29.9+/-1.1 J/mg for L. delicata) and neonates (22.5+/-1.3 J/mg for L. guichenoti and 23.5+/-0.4 J/mg for L. delicata) between species. The amount of nitrogen (protein) in neonates is only slightly lower than that in eggs, whereas there is a large and significant decline in total lipids. Thus, like some other skinks, protein is a source of metabolic energy during embryogenesis, although not as important as lipid. Triacylglycerol is the major lipid component of the eggs (80% of total lipid), with phospholipid forming only approximately 10% of the total lipid. The fatty acid profile of the phospholipid is distinguished by a high proportion of arachidonic acid (8%), a significant proportion of eicosapentaenoic acid (2-4%) and a relatively low proportion of docosahexaenoic acid (2-3%) compared to chickens. Eggs of both species have remarkably low concentrations of free cholesterol compared to other amniote eggs (0.7% for L. guichenoti and 1.3% for L. delicata). The loss of lipid during embryonic development is almost entirely due to the selective utilisation of yolk triacylglycerol, presumably for energy. By contrast, the amount of phospholipid recovered from the neonates was the same as that originally in the eggs. Moreover, significantly more total cholesterol was present in the neonates than in the eggs, suggesting that biosynthesis of additional cholesterol occurred during development. The phospholipids of the neonates contain higher proportions of arachidonic (11-12%) and docosahexaenoic (8%) acids than the phospholipids of the eggs. Eicosapentaenoic acid is less prevalent in phospholipids in neonates than in eggs. Neonates of both species contain significantly more calcium than the fresh egg contents (L. guichenoti, eggs 0.303+/-0.051 mg, neonates 0.641+/-0.047 mg; L. delicata, eggs 0.187+/-0.013 mg, neonates 0.435+/-0.033 mg), presumably as a result of resorption of calcium from the eggshell. Interestingly, there is also significantly more sodium in neonates than in the contents of fresh eggs (L. guichenoti, eggs 0.094+/-0.010 mg, neonates 0.184+/-0.011 mg; L. delicata, eggs 0.084+/-0.011 mg, neonates 0.151+/-0.010 mg). There is no significant difference in the content of potassium and magnesium in eggs and neonates of either species. Although the fresh eggs of L. delicata have a significantly higher sodium concentration than L. guichenoti, there is no difference in the concentrations of calcium, magnesium, potassium or sodium in the neonates of the two species.

Characterization of the molecular species of phosphatidylethanolamine from kidney of the fresh water snail Lymneae stagnalis by mass spectrometry

The structural analysis of sixteen molecular species of diacyl glycerophosphoethanolamine from fresh water snail Lymneae stagnalis kidney using chromatography and mass spectrometry is described in this paper. 1-eicosadienoyl-2-eicosatetraenoyl-sn-glycero-3-phosphoethanolamine (PE 20:2-20:4), 1-eicosapentaenoyl-2-eicosadienoyl-sn-glycero-3-phosphoethanolamine (PE 20:5-20:2) and 1-eicosatrienoyl-2-eicosatetraenoyl-sn-glycero-3-phosphoethanolamine (PE 20:3-20:4) as well as 1-octadecanoyl-2-eicosatetraenoyl-sn-glycero-3-phosphoethanolamine (PE 18:0-20:4), 1-ocetadecenoyl-2-eicosatetraenoyl-sn-glycero-3-phosphoethanolamine (PE 18:1-20:4) and 1-octadecanoyl-2-eicosapentaneoyl-sn-glycero-3-phosphoethanolamine (PE 18:0-20:5) were found as the major molecular species, and the first three were tentatively identified as the novel species present in this biological material. The presence of a relatively high content of 1,2-dieicosenoyl-sn-glycero-3-phosphoethanolamine species (approximately 27% of total species) as well as the absence of 22-carbon fatty acid containing and plasmalogen PE molecular species are remarkable in healthy Lymneae stagnalis kidney. Copyright 1999 John Wiley & Sons, Ltd.

Lipid composition of eggs of an oviparous lizard (Bassiana duperreyi)

Lipid analysis was performed on freshly ovulated eggs (n = 5) of the oviparous lizard Bassiana duperreyi. The fresh weight of the whole egg contents was 132.0 +/- 4.3 mg (mean +/- SE) of which lipid constituted 21.9 +/- 1.1% (w/w). Triacylglycerol formed an exceptionally high proportion (85.4 +/-0.5%, w/w) of the total lipid, whereas phospholipid, free cholesterol, cholesteryl ester, and free fatty acid, respectively, contributed 11.2 +/- 0.3, 1.4 +/- 0.1, 1.3 +/- 0.1, and 0.6 +/- 0.1% of the total lipid mass. Linoleic and alpha-linolenic acids were the major polyunsaturates of the triacylglycerol fraction, respectively, forming 16.3 +/- 0.1 and 8.3 +/- 0.1% (w/w) of the fatty acids. Linoleic acid was the major fatty acid (29.0 +/- 0.1%) of the total phospholipid, which also contained substantial amounts of arachidonic (6.4 +/- 0.1%) and eicosapentaenoic (3.0 +/- 0.1%) acids, but a relatively low proportion (1.6 +/- 0.1%) of docosahexaenoic acid. Phosphatidylcholine formed the major phospholipid class (73.8 +/- 2.3%) w/w of total phospholipid) and was enriched in linoleic acid, whereas phosphatidylethanolamine, which formed 20.4 +/- 1.9%(w/w) of total phospholipid, contained higher proportions of arachidonic and docosahexaenoic acids.

Biochemical markers for puberty in the monkey testis: desmosterol and docosahexaenoic acid

We previously reported that the sperm of rhesus monkeys and humans uniquely contain large amounts of desmosterol not found in other tissues and have a high concentration of the highly polyunsaturated n-3 fatty acid, docosahexaenoic acid (22:6 n-3). However, the lipid composition of the testis, from which sperm originate, is unknown. During puberty, the testis undergoes remarkable morphological changes as testosterone levels rise and sperm production begins. We hypothesized that testicular maturation might also involve dramatic changes in lipid composition. Accordingly, we characterized the sterol and fatty acid composition of the testis of rhesus monkeys throughout the lifespan, from birth to old age. Although the cholesterol content in the testis remained relatively unchanged throughout life, the desmosterol content first decreased from 59 microg/g in infants to 6 microg/g in prepubertal monkeys, increased to 83 microg/g during puberty, and reached a plateau of 248 microg/g in the young adult, where it remained into old age. The polyunsaturated fatty acid composition of the testis also changed markedly. Docosahexaenoic acid (22:6 n-3) increased from 5.1% of total fatty acids in infants and juveniles to 18.1% in postpubertal young adults. Although some n-6 fatty acids, arachidonic (20:4 n-6) and linoleic (18:2 n-6), decreased from 16.0% and 10.0% in prepubertal juveniles, respectively, to 7.1% and 3.3% in young adults; dihomogamma-linolenic acid (20:3 n-6), the precursor of 1 series PGs, increased greatly from 1.8% to 10.3%. Similar changes occurred in both membrane and storage lipids (phospholipids and triglycerides), respectively. After puberty, the testicular fatty acid pattern remained stable into old age. Our data demonstrated that puberty is accompanied by substantial changes in the lipid composition of the primate testis. These changes suggest that desmosterol and both n-3 and n-6 polyunsaturated fatty acids may have important roles in sexual maturation.