Changes in the lipid and fatty acid composition of hemolymph and ovaries during the reproductive cycle of Labidura riparia

Lipid metabolism was investigated during the reproductive cycle of Labidura riparia (Pallas). The lipid classes and their constitutive fatty acids present in hemolymph and ovaries were measured using thin‐layer chromatography and gas‐liquid chromatography. In the hemolymph, total lipids increase steadily from the previtellogenic period to vitellogenic arrest. These lipids are predominantly diacylglycerols and phospholipids. In the ovaries, total lipids increase during vitellogenesis then decrease during the vitellogenesis arrest period. The major lipids are triacylglycerols, followed by phospholipids. In both hemolymph and ovaries, all lipid classes contained variable proportions of seven main fatty acids: the saturated fatty acids myristic acid (14:0), palmetic acid (16:0), and stearic acid (18:0); the monounsaturated fatty acids palmitoleic acid (16:1) and oleic acid (18:1); and the polyunsaturated fatty acids linoleic acid (18:2) and linolenic acid (18:3). Unsaturated fatty acids predominate throughout the reproductive cycle. The percentage compositions of total and triacylglycerol fatty acids do not change markedly during the reproductive cycle in hemolymph nor in ovaries, with 18:2, 18:1 and 16:0 fatty acids being the major components. However, for diacylglycerols and phospholipids, the proportions of fatty acids vary systematically. For phospholipids during the vitellogenesis period, 18:2 increases considerably whereas other fatty acids decrease; for diacylglycerols, these fatty acids vary in the reverse way.     

镉胁迫对平邑甜茶脂肪酸构成及脂质过氧化的影响

以平邑甜茶幼苗为试材,研究了镉胁迫下幼苗叶片和根系膜脂肪酸构成、活性氧、脂氧合酶和丙二醛含量的变化.结果表明：氯化镉处理后7～12 h,脂肪酸种类及其相对含量变化最为明显.处理后7 h,叶片和根系脂肪酸不饱和水平升至最高,含量分别达8282%和7243%;叶片可检测到的脂肪酸在处理后12 h由11种增至14种,根系则在处理17 h后由4种增至6种.O₂^.-产生速率在处理3 h、H₂O₂含量在处理7 h时升至最高,丙二醛含量和脂氧合酶活性则随着处理时间的延长逐渐增加.镉胁迫通过诱导活性氧和脂氧合酶来改变平邑甜茶脂肪酸构成,并引起脂质过氧化;镉处理12 h前,脂质过氧化是活性氧和脂氧合酶的共同结果;但处理12 h后,脂质过氧化加剧主要在于脂氧合酶活性的持续增加.     

光照强度对四株海洋绿藻总脂含量和脂肪酸组成的影响

采用f/2培养基,在3000lx,5000lx,8000lx光照强度时对杆状裂丝藻(Stichococcus bacillaris,MACC(中国海洋大学微藻种质库)/C19)和3株小球藻(Chlorellasp.MACC/C95,MACC/C97和MACC/C102)等4株海洋绿藻的总脂含量及脂肪酸组成进行了研究。单因子方差分析结果表明,光照强度对4株海洋绿藻的相对生长率、EPA(二十碳五烯酸,20∶5(n-3))含量及PUFA(多不饱和脂肪酸)总量,C19、C97和C102的脂肪含量和SFA(饱和脂肪酸)总量,C19、C95和C102的MUFA(单不饱和脂肪酸)总量均有显著影响(P0.05)。C19和C95的总脂含量随光照强度的增加总体呈降低趋势,C97和C102的总脂含量则随光照强度的升高而明显升高。C19的EPA含量随光照强度的增加呈现低-高-低趋势,C95在中低光照强度下EPA含量较高,C97和C102的EPA含量则随光照强度的增加而明显降低,4株绿藻的AA(花生四烯酸,20∶4(n-6))含量和PUFA总量均随光照强度的增加而降低。多重比较结果表明:C19在高光照强度(8000lx)时总脂含量显著低于其它各组,低光照强度(3000lx)和中光照强度(5000lx)处理间没有显著性差异(12.9%—12.7%),C97和C102则分别在高光照强度时总脂含量显著高于其它各处理(分别为40.6%和33.3%)。C19的EPA含量在中光照强度水平显著高于其它处理(12.7%),C97和C102的EPA含量分别在低光照强度水平显著高于其它处理(分别为12.0%和10.5%),C95的EPA含量在高光照强度水平显著低于其它处理,低光照强度和中光照强度处理间没有显著性差异(14.0%—14.7%);C19和C95的PUFA总量均在高光照强度水平显著低于其它处理,在低光照强度和中光照强度处理间没有显著性差异(分别为19.1%—19.4%和21.3%—21.3%),C97和C102的PUFA总量均在低光照强度水平显著高于其它处理(分别为19.2%和18.9%)。4株绿藻的主要脂肪酸成份为14∶0、16∶0、16∶1(n-7)、16∶4(n-3)、18∶1(n-9)、18∶3(n-3)、20∶4(n-6)和EPA。     

Effects of ambient temperature on lipid and fatty acid composition in the oviparous lizards, Phrynocephalus przewalskii

This study was designed to assess the effect of ambient temperature on lipid content, lipid classes and fatty acid compositions of heart, liver, muscle and brain in oviparous lizards, Phrynocephalus przewalskii, caught in the desert area of China. Significant differences could be observed in the contents of the total lipid and fatty acid compositions among different temperatures (4, 25 and 38 degrees C). The study showed that liver and muscle were principal sites of lipid storage. Triacylglycerol (TAG) mainly deposited in the liver, while phospholipids (PL) was identified as the predominant lipid class in the muscle and brain. Palmitic and stearic acid generally occupied the higher proportion in saturated fatty acids (SFA), while monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) consisted mainly of 16:1n-7, 18:1n-9, 18:2n-6, 18:3n-3, 20:4n-6 and 22:6n-3 regardless of tissue and temperature. These predominant fatty acids proportion fluctuations caused by temperature affected directly the ratio of unsaturated to saturated fatty acids. There was a tendency to increase the degree of unsaturation in the fatty acids of TAG and PL as environmental temperature dropped from 38 to 4 degrees C, although the different extent in different tissues. These results suggested that lipid characteristics of P. przewalskii tissues examined were influenced by ambient temperature.     

Effects of postnatal age and diet on the fatty acid composition of plasma lipid fractions in preterm infants

Diet and postnatal age effect the fatty acid composition of plasma and tissue lipids. This work was designed as a transversal study to evaluate the changes in the fatty acid composition of plasma phospholipids, cholesteryl esters, triglycerides and free fatty acids in preterm infants (28-35 weeks gestational age), fed human milk (HM) and milk formula (MF) from birth to 1 month of life. Sixteen blood samples were obtained from cord, and 19 at 6-8 h after birth, 14 at 1 week and 9 at 4 weeks from HM-fed infants and 18 at 1 week and 14 at 4 weeks from MF-fed ones. Groups had similar mean birth weight, gestational age and sex ratio. The MF provided 69 kcal/dl and contained 16% of linoleic acid and 1.3% of alpha-linolenic acid on the total fat. Plasma lipid fractions were extracted and separated by thin-layer chromatography and fatty acid methyl esters were quantitated by gas liquid chromatography. In plasma phospholipids, linoleic acid (18:2 omega 6) continuously increased from birth to 1 month of age, but no changes were seen as related to type of diet; polyunsaturated fatty acids greater than 18 carbon atoms of both the omega 6 and omega 3 series (PUFA omega 6 greater than 18 C and omega 3 greater than 18 C) dropped from birth to 1 week and continued to decrease in MF-fed infants until 1 month; eicosatrienoic (20:3 omega 6), arachidonic (20:4 omega 6) and docosahexaenoic (22:6 omega 3) were the fatty acids implicated. In cholesteryl esters palmitoleic (16:1 omega 7) and oleic (18:1 omega 9) acids decreased from birth to 1 month and linoleic acid increased and arachidonic acid dropped, especially in MF fed infants. In triglycerides, palmitic, palmitoleic and stearic acid (18:0) decreased during the first month of life; oleic acid remained constant and linoleic acid increased in all infants, but arachidonic acid decreased only in those fed formula. Free fatty acids showed a similar behavior in fatty acids and in plasma triglycerides. Preterm neonates seem to have special requirements of long-chain PUFA and adapted MF should contain these fatty acids in similar amounts to those of HM to allow the maintenance of an adequate tissue structure and physiology.     

Variation in lipid classes and fatty acid composition of salmon shark (Lamna ditropis) liver with season and gender

The influence of season and gender on lipid content, lipid classes, and fatty acid compositions was assessed in livers of salmon shark (Lamna ditropis), caught in the Pacific Ocean. No significant difference in the hepatosomatic index was noted with season, though the lipid content was significantly higher (P<0.05) in winter. Triacylglycerol (TAG) was identified as the predominant lipid class (78.5-82.0%), followed by sterol esters (5.7-9.1%) and hydrocarbons (3.4-5.4%). No significant differences were observed in TAG composition with respect to the season or gender. However, diacylglyceryl ether contents were significantly higher (P<0.05) in winter (3.8-5.3%) than those obtained in summer (1.3-1.1%). Polyunsaturated fatty acids constituted the major fatty acid class of salmon shark total liver lipid and docosahexaenoic acid (C22:6n-3) (22.7-28.4%) was the most abundant fatty acid which was significantly lower (P<0.05) in winter. These results suggested that lipid characteristics of salmon shark liver were influenced by season, but not by gender.     

Effect of glutamic acid on the fatty acid and lipid composition of Choanephora cucurbitarum.

The fatty acid composition of the total, neutral, sterol, free fatty acid, and polar-lipid fractions in the mycelium of Choanephora curcurbitarum was determined. The major fatty acids in all lipid fractions were palmitic, oleic, linoleic, and gamma-linolenic acid. Different lipid fractions did not show any particular preference for any individual fatty acid; however, the degree of unsaturation was different in different lipid fractions. Free fatty acid and polar lipid fractions contained a higher proportion of gamma-linolenic acid than did triglyceride and sterol fractions. Addition of glutamic acid to the malt-yeast extract and medium resulted in the biosynthesis of a number of long-chain fatty acids beyond the gamma-linolenic acid. These fatty acids, e.g., C22:1, C24:0, and C26:0, were never observed to be present in the fungus when grown on a malt-yeast extract medium without glutamic acid. Furthermore, thin-layer chromatographic analysis showed a larger and denser spot of diphosphatidyl glycerol from the mycelium grown on glutamic acid medium than from the control mycelium. The possible significance of this finding is discussed.     

Effect of season on the fatty acid composition and free amino acid content of the sardine Sardinops melanostictus

The purpose of this study was to clarify the seasonal variation of fatty acid composition and free amino acid content in the Japanese sardine (Sardinops melanostictus) from the sea of Hyuga-Nada, and the relationship between the fatty acid composition of this sardine and that of plankton in the area. The lipid content of sardines at the sea of Hyuga-Nada was low in February (1.8%) and high (7.2%) from July to September. The major fatty acids in the total lipids from sardine were myristic acid (14:0), palmitic acid (16:0), stearic acid (18:0), palmitoleic acid (16:1 n-7), oleic acid (18:1 n-9), eicosapentaenoic acid (20:5 n-3), and docosahexaenoic acid (22:6 n-3). The characteristics of the fatty acids isolated from sardines in July were similar to those from plankton in the same season. This reflects the deposition of plankton fatty acids in sardine depot fat. The season of high free histidine content in the ordinary meat corresponded with that of high lipid content. These results suggested that both the fatty acid composition of sardines and the high concentrations of certain amino acids in free form are influenced by the intake and seasonal variation of composition of plankton.     

Spawning and season affect lipid content and fatty acid composition of ovary and liver in Japanese catfish (Silurus asotus)

The influences of spawning and season on lipid content, lipid classes, and fatty acid composition were assessed in ovary and liver of wild and cultured Japanese catfish (Silurus asotus). The lipid content (7.3+/-1.6 g/100 g wet wt.) of ovary from wild catfish at spawning was higher than that at post-spawn. However, no influence of spawning on the lipid content of liver was observed. Docosahexaenoic acid [DHA, C22:6(n-3)] in ovary lipids was 12.3+/-0.5% of total fatty acids. The percentage of n-7 monounsaturated fatty acids in triacylglycerol from the ovary and liver in the spawning season was high. Percentages of C22:6(n-3) in phosphatidylcholine and phosphatidylethanolamine from ovary were higher during spawning than after spawning. No significant differences were observed in the lipid content of ovary and liver from cultured catfish between seasons (summer vs. winter). Content of arachidonic acid (C20:4n-6) in ovary and liver from cultured catfish was higher in summer than in winter. There were differences in lipid classes of ovary and liver by spawning and season. These results suggest that the lipid metabolism in Japanese catfish is greatly influenced by spawning and season.     

Effects of fatty acid deficiency on the lipid composition and physical properties of guinea pig rough endoplasmic reticulum

Twenty-six days of fat deficiency brought about a decrease of linoleic and an increase of oleic acid in rough endoplasmic reticulum (RER) of guinea pig liver. Arachidonic acid was only slightly decreased in some phospholipids whereas eicose-5,8,11-trienoic acid was not enhanced except in phosphatidyl-inositol. All these changes were relevant specifically in phosphatidylinositol molecules and less important in phosphatidylcholine and phosphatidylethanolamine. Fat deficiency did not modify the relative proportion of phospholipids and cholesterol. Therefore, fat deficient guinea pig microsomes are a good model to study the effect of unsaturated fatty acids on membrane properties. Fluorescent anisotropy of RER membranes, lipids and phospholipids labeled with diphenylhexatriene, was increased by the fat deficiency. The most important increase was observed in liposomes of a mixture of RER phosphatidylinositol, phosphatidylserine and sphingomyelin. A small change was found in phosphatidylcholine and phosphatidylethanolamine dispersions at 37°C. The modification of the lipid unsaturation evoked fluorescent anisotropy changes. Temperature-dependent fluorescent polarization curves of RER membranes labeled with trans-parinaric acid did not show inflections in the temperature range from 5 to 45°C but, RER lipids and phospholipids presented a phase separation at about 20°C. This inflection point was not modified by the fat deficient diet. In those liposomes prepared with a mixture of RER phosphatidylinositol, phosphatidylserine and sphingomyelin, the inflection point was produced at about 37°C.The author is member of the Carrera del Investigador Cientifico, Consejo Nacional de Investigaciones Cientificas y Técnicas, Argentina.     

Feeding habitat and silvering stage affect lipid content and fatty acid composition of European eel Anguilla anguilla tissues

Lipids, particularly fatty acids (FAs), are major sources of energy and nutrients in aquatic ecosystems and play key roles during vertebrate development. The European eel Anguilla anguilla goes through major biochemical and physiological changes throughout its lifecycle as it inhabits sea- (SW), and/or brackish- (BW) and/or freshwater (FW) habitats. With the ultimate goal being to understand the reasons for eels adopting a certain life history strategy (FW or SW residency vs. ‘habitat shifting’), we explored differences in lipid content and FA composition of muscle, liver and eyes from eels collected across Norwegian SW, BW and FW habitats, and at different lifecycle stages (yellow to silver). FW and SW eels had a higher lipid content overall compared to BW eels, reflecting differences in food availability and life history strategies. SW eels had higher proportions of certain monounsaturated FAs (MUFAs; 18:1n-9, 20:1n-9), and of the essential polyunsaturated FAs 20:5n-3 (eicosapentaenoic acid, EPA) and 22:6n-3 (docosahexaenoic acid) than FW eels, reflecting a marine-based diet. In contrast, the muscle of FW eels had higher proportions of 18:3n-3, 18:2n-6 and 20:4n-6 (arachidonic acid), as is typical of FW organisms. MUFA proportions increased in later stage eels, consistent with the hypothesis that the eels accumulate energy stores prior to migration. In addition, the decrease of EPA with advancing stage may be associated with the critical role that this FA plays in eel sexual development. Lipid and FA information provided further understanding of the habitat use and overall ecology of this critically endangered species.     

Production of microbial lipid: Effects of growth rate and oxygen on lipid synthesis and fatty acid composition of Rhodotorula gracilis

Microbial lipids produced by Rhodotorula gracilis NRRL Y-1091 grown in continuous culture under nitrogen-limiting condition were evaluated and the effects of growth rate and oxygen concentration on the degree of unsaturatoin of fatty acids studied. As the growth rate increased the protein content of the biomass increased but cell biomass, lipid content, and lipid productivity decreased; the specific lipid production rate remained constant at about 0.012 g lipid/g dry biomass/h. The maximum lipid content recorded was 49.8% (w/w) of the cell mass at a growth rate of 0.02 h(-1). The growth rate also affected fatty acid composition; polyunsaturated fatty acids (C18:2 and C18:3) increaded with growth rate while other fatty acids (C16:0, C18:0, C18:1) decreased. Increase in oxygen concentration between 5 and 234muM increased the lipid content without significantly affecting its degree of unsaturation. On the other hand, the degree of unsaturation was significantly affected by specific oxygen uptake rate for this obligate aerobe, Rh. gracilis.     

Fatty acid desaturation and microsomal lipid fatty acid composition in experimental hypothyroidism.

We have studied the influence of experimental hypothyroidism in the rat on the synthesis of unsaturated fatty acids and on liver microsomal lipid fatty acid composition. Hypothyroid rats demonstrated an 80% decrease in delta 9 (stearate) desaturation and a 43% decrease in delta 6 (linoleate) desaturation. Liver microsomal fatty acid composition was altered in the hypothyroid animals with a significantly decreased proportion of arachidonate and increased proportions of linoleate, eicosa-8,11,14-trienoate, eicosapentaenoate and docosahexaenoate. The bulk of these changes occurred in both of the two major phospholipid components, phosphatidylcholine and phosphatidylethanolamine. All of the changes were corrected by treatment of the hypothyroid rat with 25 micrograms of tri-iodothyronine/100 g body wt. twice daily. The diminished delta 9 desaturation did not lead to any changes in fatty acid composition. The increased linoleate and decreased arachidonate levels may be due to the diminished delta 6 desaturase activity, the rate-controlling step in the conversion of linoleate into arachidonate. The increases in the proportions of the other polyunsaturated fatty acid components cannot be explained by changes in the synthesis of unsaturated fatty acids, but are probably due to diminished utilization of these fatty acids.     

Ontogenetic change in the lipid and fatty acid composition of scleractinian coral larvae

Some scleractinian coral larvae have an extraordinary capacity to delay metamorphosis, and this is reflected in the large geographic range of many species. Coral eggs typically contain a high proportion of wax esters, which have been hypothesized to provide a source of energy for long-distance dispersal. To better understand the role of lipids in the dispersal of broadcast spawning coral larvae, ontogenetic changes in the lipid and fatty acid composition of Goniastrea retiformis were measured from the eggs until larvae were 30 days old. Egg biomass was 78.8 ± 0.5% lipids, 86.3 ± 0.2% of which were wax esters, 9.3 ± 0.0% polar lipids, 4.1 ± 0.2% sterols, and 0.3 ± 0.1% triacylglycerols. The biomass of wax esters declined significantly through time, while polar lipids, sterols and triacylglycerols remained relatively constant, suggesting that wax esters are the prime source of energy for development. The most prevalent fatty acid in the eggs was palmitic acid, a marker of the dinoflagellate Symbiodinium, highlighting the importance of symbiosis in coral reproductive ecology. The proportion of polyunsaturated fatty acids declined through time, suggesting that they are essential for larval development. Interestingly, triacylglycerols are only abundant in the propagules that contain Symbiodinium, suggesting important differences in the energetic of dispersal among species with vertical and horizontal transmission of symbionts.     

Effects of carbon and nitrogen sources on fatty acid contents and composition in the green microalga, Chlorella sp. 227

In order to investigate and generalize the effects of carbon and nitrogen sources on the growth of and lipid production in Chlorella sp. 227, several nutritional combinations consisting of different carbon and nitrogen sources and concentrations were given to the media for cultivation of Chlorella sp. 227, respectively. The growth rate and lipid content were affected largely by concentration rather than by sources. The maximum specific growth was negatively affected by low concentrations of carbon and nitrogen. There is a maximum allowable inorganic carbon concentration (less than 500~1,000 mM bicarbonate) in autotrophic culture, but the maximum lipid content per gram dry cell weight (g DCW) was little affected by the concentration of inorganic carbon within the concentration. The lipid content per g DCW was increased when the microalga was cultured with the addition of glucose and bicarbonate (mixotrophic) at a fixed nitrogen concentration and with the lowest nitrogen concentration (0.2 mM), relatively. Considering that lipid contents per g DCW increased in those conditions, it suggests that a high ratio of carbon to nitrogen in culture media promotes lipid accumulation in the cells. Interestingly, a significant increase of the oleic acid amount to total fatty acids was observed in those conditions. These results showed the possibility to induce lipid production of high quality and content per g DCW by modifying the cultivation conditions.