Polyunsaturated dietary lipids lower the selected body temperature of a lizard

Summary Cold acclimation lowers the selected body temperature (T _b) in many ectothermic vertebrates. This change in behavioural thermoregulation is accompanied by an increase in the proportion of polyunsaturated fatty acids in tissues and cellular membranes. We investigated how diets containing different fatty acids, known to significantly alter the fatty acid composition of animal tissues and membranes, affect the selected T _b of the lizard Tiliqua rugosa. Lizards on a diet containing many polyunsaturated fatty acids (10% sunflower oil) showed a 3–5°C decrease in T _b, whereas T _b in animals on a diet containing mainly saturated fatty acids (10% sheep fat) did not change. Our study suggests that the composition of dietary lipids influences thermoregulation in ectothermic vertebrates and may thus play a role in the seasonal adjustment of their physiology.Abbreviations CST central standard time - T _a air temperature - T _b Body temperature     

The impact of dietary fats,photoperiod, temperature and season on morphological variables,torpor patterns,and brown adipose tissue fatty acid composition of hamsters,Phodopus sungorus

We investigated how dietary fats and oils of different fatty acid composition influence the seasonal change of body mass, fur colour, testes size and torpor in Djungarian hamsters, Phodopus sungorus, maintained from autumn to winter under different photoperiods and temperature regimes. Dietary fatty acids influenced the occurrence of spontaneous torpor (food and water ad libitum) in P. sungorus maintained at 18°C under natural and artificial short photoperiods. Torpor was most pronounced in individuals on a diet containing 10% safflower oil (rich in polyunsaturated fatty acids), intermediate in individuals on a diet containing 10% olive oil (rich in monounsaturated fatty acids) and least pronounced in individuals on a diet containing 10% coconut fat (rich in saturated fatty acids). Torpor in P. sungorus on chow containing no added fat or oil was intermediate between those on coconut fat and olive oil. Dietary fatty acids had little effect on torpor in animals maintained at 23°C. Body mass, fur colour and testes size were also little affected by dietary fatty acids. The fatty acid composition of brown fat from hamsters maintained at 18°C and under natural photoperiod strongly reflected that of the dietary fatty acids. Our study suggests that the seasonal change of body mass, fur colour and testes size are not significantly affected by dietary fatty acids. However, dietary fats influence the occurrence of torpor in individuals maintained at low temperatures and that have been photoperiodically primed for the display of torpor.Abbreviations BAT brown adipose tissue - bm body mass - FA fatty acid(s) - MR metabolic rate - MUFA monounsaturated fatty acid(s) - PUFA polyunsaturated fatty acid(s) - SFA saturated fatty acid(s) - T _a air temperature - T _b body temperature - T_s body surface temperature(s) - TNZ thermoneutral zone - UFA unsaturated fatty acid(s)     

Effect of growth temperature on the fatty acid composition of Mycobacterium phlei

In Mycobacterium phlei, fatty acid unsaturation increased with decreasing temperature. The 10-hexadecenoic acid content increased as the temperature was reduced from 35°C to 26–20°C. At lower temperatures tuberculostearic acid decreased while oleic and linoleic acids increased, the latter being found in M. phlei for the first time. Concomitantly palmitic acid content decreased, and the 6- and 9-hexadecenoic acids increased slightly on reducing the temperature from 35 to 10°C. Thus, down to 26–20°C palmitic acid was mainly replaced by 10-hexadecenoic acid. From this range down to 10°C, palmitic and tuberculostearic acids were replaced by oleic and linoleic acids. Consequently, fatty acid branching decreased and mean chain length increased, as the temperature was reduced. These observations support the view that regulation of membrane fatty acid composition is part of microbial temperature adaptation, and that themechanism behind the responses might be more complex than generally believed.Abbreviations ACP acyl carrier protein - FAS I (Type I) fatty acid synthetase I - FAS II (Type II) fatty acid synthetase II - MGLP methylglucose containing lipopolysaccharide - MMP methylmannose containning polysaccharide     

Fatty acid composition of selected prosthecate bacteria

The cellular fatty acid composition of 14 strains of Caulobacter species and types, two species of Prosthecomicrobium, and two species of Asticcacaulis was determined by gas-liquid chromatography. In most of these bacteria, the major fatty acids were octadecenoic acid (C18:1), hexadecenoic acid (C16:1) and hexadecanoic acid (C16:0). Some cyclopropane and branched chain fatty acids were detected in addition to the straight chained acids. Hydroxytetradecanoic acid was an important component of P. enhydrum but significant amounts of hydroxy acids were not detected in other prosthecate bacteria examined.Abbreviations DEGS diethylene glycol succinate - A measare of association Dedicated to Prof. R. Y. Stanier on the occasion of his 60th birthday     

Alterations in growth temperature range and fatty acid composition of Thermus as a result of plasmid elimination

Elimination of plasmids from Thermus flavus, T. thermophilus and three wild Thermus strains caused alterations in growth temperature range, pigmentation and membrane fatty acids without affecting viability. Following plasmid elimination all Thermus strains lost their ability to grow above 70°C. In addition, the minimum growth temperature was lowered by 5–10°C. Fatty acids were reduced by an average of approximately 35%. In addition, the contribution of iso- and anteisobranched fatty acids were altered in four of the five strains. The iso C_15:0/iso C_17:0 ratio approached 1.0 in all strains, whereas the anteiso C_15:0/anteiso C_17:0 was reduced to 0.2. The iso C_16:0/normal-C_16:0 ratio increased in all strains due to an increase in iso C_16:0 in four strains and a reduction in normal-C_16:0 relative to iso C_16:0 in one strain. However, it was evident that the plasmid-free strains were able to compensate for these alterations in membrane fluidity to a certain extent by reducing the average chain length of isobranched acids. Altered fatty acid metabolism at the level of precursors may have influenced membrane composition and consequently growth temperature range.     

Fatty acid,menaquinone and polar lipid composition of Rothia dentocariosa

The lipid compositions of Rothia dentocariosa was investigated. All of the strains tested possessed closely related lipid profiles consisting of predominantly straight-chain saturated and methyl branched long-chain fatty acids, unsaturated menaquinones with seven isoprene units and a polar lipid composition comprising diphosphatidylglycerol, phosphatidylglycerol and a diglycosyldiacylglycerol. The results of the present study indicate Rothia dentocariosa is a good and distinct taxon. The lipid data however does not support the classification of Rothia dentocariosa in the family Actinomycetaceae.     

Dietary fatty acid composition differently influences retinoylation reaction in rat testes mitochondria

All-trans-retinoic acid (atRA) is incorporated covalently into proteins of rat testes mitochondria. In this study, the effect of three diets with different fatty acid composition on the retinoylation of proteins of rat testes mitochondria has been investigated. Different groups of rats were fed on a basal diet supplemented with 15% of either coconut oil (CO), olive oil (OO) or fish oil (FO). We found that, when compared with CO, the binding of retinoic acid was decreased in FO- and OO-fed rats. Mitochondrial phospholipids composition was differently influenced by dietary treatments; minor changes were observed in fatty acid composition of phospholipids. Few differences were observed in the Arrhenius plots among the three groups of rats. Kinetic analysis revealed a decrease in the V _max value in FO- and OO- as compared with CO-fed rats. No difference among the three groups were observed in the K _M value. The retinoylation reaction was inhibited by 13-cis-RA and 9-cis-RA.     

Effect of keratin on the lipid composition of Scopulariopsis brevicaulis (Bainier)

Lipid content and composition of Scopulariopsis brevicaulis cultured with or without its natural substrate keratin was investigated. Lipid content was found to be lower in the presence of keratin (maximum 12% against 19% in the absence of keratin), with differences in levels of linoleic acid (C₁₈₌₂), palmitic (C₆₀) and to a lesser extent palmitoleic (C₁₆₌₁) and -linolenic (C₁₈₌₃) acids. The degree of unsaturation was correspondingly lower in the organisms cultured with keratin as substrate.     

Lipid classes and fatty acid composition of rotifers (Brachionus plicatilis) fed two algal diets

Rotifers (Brachionus plicatilis), maintained on baker's yeast, were fed for 24h upon two algal diets, Isochrysis galbana (diet A) and Isochrysis galbana + Nannochloropsis gaditana (diet B). (These algal diets were selected for their potential use as essential fatty acid (EFA) boosters, taking into account the requirements of fish larvae). The effect of these algal diets on total lipid content, lipid classes and fatty acid composition was studied. The total lipid content increased after feeding upon both diets but no significant differences were found between the two types. Neutral lipid and polar lipid contents increased and a positive correlation was observed between the neutral lipids content of rotifers and that of the food supplied. However, the content of polar lipids in rotifers did not depend upon that of the diet. The increase in neutral lipid content was found to be higher in rotifers fed upon diet B, compared to diet A which increased the phospholipid content. Non-enriched rotifers contained only small amounts of polyenoic fatty acids, i.e. 18:3n-6, 18:3n-3, 20:4n-6, 20:5n-3 and 22:6n-3, the contents of which increased significantly by feeding both diets. The EFA composition (20:4n-6, 20:5n-3 and 22:6n-3) of neutral lipids and phopholipids in rotifers reflected the EFA composition of each diet. Diet B-fed rotifers had the highest content in 20:4n-6 and 20:5n-3, whereas rotifers fed diet A and the highest 22:6n-3 content. The mixed diet I. galbana + N. gaditana enhanced substantially the composition of lipid classes i.e. neutral lipids and of n-3 PUFA of rotifers in comparison with Isochrysis or yeast diets.     

Interseasonal variation in the circadian rhythms of locomotor activity and temperature selection in sleepy lizards, <Emphasis Type="Italic">Tiliqua rugosa</Emphasis>

Few studies in non-mammalian vertebrates have examined how various effectors of the circadian system interact. To determine if the daily locomotor and behavioural thermoregulatory rhythms of Tiliqua rugosa are both controlled by the circadian system in different seasons, lizards were tested in laboratory thermal gradients in four seasons and in constant darkness. Circadian rhythmicity for both rhythms was present in each season, being most pronounced in spring and summer and least evident in autumn. Most lizards displayed a unimodal locomotor activity pattern across all seasons. However, some individuals presented a bimodal locomotor activity pattern in spring and summer. Seasonal variations in the phase relationships of both rhythms to the light:dark (LD) cycle were demonstrated. No seasonal differences in the free-running period lengths of either rhythm were detected, raising the possibility that a single circadian pacemaker drives both rhythms in this species. Our present results demonstrate that both rhythms are similarly controlled by the circadian system in each season. Although seasonal variations in the thermal preferences of reptiles both in the field and laboratory have previously been well documented, this study is the first to demonstrate circadian rhythms of temperature selection in a reptile species in each season.     

Polar lipids and fatty acid composition ofThermus strains from New Zealand

The polar lipids and fatty acid composition ofThermus aquaticus YT-1 and YS 041,T. filiformis Wai33 A1 and eighteen isolates from New Zealand, several of which are attributed toT. filiformis, were compared to complement the taxonomy of these organisms. The polar lipid patterns were essentially similar in all strains and consisted of one major phospholipid and one major glycolipid. The fatty acid analysis produced three basic groups corresponding toT. filiformis Wai33 A1,T. aquaticus and the third to the other New Zealand strains. The presence of hydroxy fatty acids is reported inThermus spp. for the first time.     

The effect of unsaturated and saturated dietary lipids on the pattern of daily torpor and the fatty acid composition of tissues and membranes of the deer mouse Peromyscus maniculatus

Summary Dieary lipids strongly influence the pattern of torpor and the body lipid composition of mammalian hibernators. The object of the present study was to investigate whether these diet-induced physiological and biochemical changes also occur in species that show shallow, daily torpor. Deer mice, Peromyscus maniculatus, were fed with rodent chow (control diet) or rodent chow with either 10% sunflower seed oil (unsaturated diet) or 10% sheep fat (saturated diet). Animals on the unsaturated diet showed a greater occurrence of torpor (80–100% vs 26–43%), longer torpor bouts (4.5 vs 2.25 h), a lower metabolic rate during torpor (0.96 vs 2.25 ml O₂·g^-1·h^-1), and a smaller loss of body mass during withdrawal of food (2.35 vs 3.90 g) than animals on the saturated diet; controls were intermediate. These diet-induced physiological changes were associated with significant alterations in the fatty acid composition of depot fat, leg muscle and brain total lipids, and heart mitochondrial phospholipids. Significant differences in the total unsaturated fatty acid (UFA) content between animals on saturated and unsaturated diet were observed in depot fat (55.7% vs 81.1%) and leg muscle (56.4% vs 72.1%). Major compositional differences between diet groups also occurred in the concentration of n6 and/or n3 fatty acids of brain and heart mitochondria. The study suggests that dietary lipids may play an important role in the seasonal adjustment of physiology in heterothermic mammals.Abbreviations EDTA ethylenediaminetetra-acetic acid - HEPES N-2 hydroxyethylpiperazine-N¹-2-ethanesulphonic acid - MUFA monounsaturated fatty acids - PUFA polyunsaturated fatty acids - RMR Testing metabolic rate - SD standard deviation - SFA saturated fatty acids - SNK Student-Newman-Keuls test - T₁ air temperature - T_b body temperature - UFA unsaturated fatty acids - rate of oxygen consumption Dedicated to the late John K. Raison     

The effects of temperature on the fatty acid and phospholipid composition of four obligately psychrophilicVibrio Spp.

The free fatty acid and phospholipid composition of 4 psychrophilic marineVibrio spp. have been determined in chemostat culture with glucose as the limiting substrate over a temperature range 0–20°C. All the isolates show maximum glucose and lactose uptake at 0°C and this correlates with maximum cell yield. None of the isolates contain fatty acids with a chain length exceeding 17 carbon atoms.Vibrio AF-1 andVibrio AM-1 respond to decreased growth temperatures by synthesizing increased proportions of unsaturated fatty acids (C15:1, C16:1 and C17:1) whereas inVibrio BM-2 the fatty acids undergo chain length shortening. The fourth isolate (Vibrio BM-4) contains high levels (60%) of hexadecenoic acid at all growth temperatures and the fatty acid composition changes little with decreasing temperature. The principal phospholipid components of the four psychrophilic vibrios were phosphatidylserine, phosphatidylglycerol, phosphatidylethanolamine and diphosphatidylglycerol. Lyso-phosphatidylethanolamine and 2 unknown phospholipids were additionally found inVibrio AF-1. The most profound effect of temperature on the phospholipid composition of these organisms was the marked increase in the total quantities synthesized at 0°C. At 15°C phosphatidylglycerol accumulated in the isolates as diphosphatidylglycerol levels decreased. Additionally inVibrio BM-2 andVibro BM-4 phosphatidylserine accumulates as phosphatidylethanolamine biosynthesis was similarly impaired. The observed changes in fatty acid and phospholipid composition in these organisms at 0°C may explain how solute transport is maintained at low temperature.Abbreviations PS Phosphatidylserine - PE phosphatidylethanolamine - PG phosphatidylglycerol - DPG diphosphatidylglycerol - lyso PE lysophosphatidylethanolamine     

Different fatty acid composition in central and peripheral adipose tissues of the American mink (Mustela vison)

Fatty acid (FA) composition in the intraabdominal (IAB), subcutaneous (SC) and peripheral adipose tissues of the semiaquatic American mink (Mustela vison) was examined in comparison to the diet by gas-liquid chromatography. There was a clear compositional gradient from the IAB via SC to peripheral adipose tissues and the anatomically different adipose tissues accumulated or metabolized FA selectively. The total lipids of the body appendages had smaller proportions of saturated (SFA) and larger proportions of monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA) than the lipids of the trunk adipose tissues. Especially n-3 PUFA were enriched in the periphery. The appendages were also characterized with a high ratio of unsaturated FA to SFA, an increased Delta9-desaturation index and increased mean numbers of double bonds and carbon atoms in a FA molecule. The proportions of SFA and MUFA of the diet resembled the trunk adipose tissues while the dietary percentage of n-3 PUFA surpassed those of the trunk fat depots but was lower than those of the peripheral fats. These data confirm that the FA signatures of mammals reflect not only their dietary history but also metabolic modifications of ingested FA.     

Changes in fatty acid composition of Mytilus galloprovincialis (Lmk) fed on microalgal and wheat germ diets

Dietary fatty acid incorporation and changes in various lipid and phospholipid classes in the mussel Mytilus galloprovincialis subjected to three different dietary regimens were analysed and compared. Group A was unfed; group B received a diet consisting of 100% Thalassiosira weissflogii, exhibiting the typical fatty acid composition of diatoms, and group C received a diet consisting of 100% wheat germ conferring a 18:2:n-6 abundance. Biochemical analyses of diets and mussels were carried out at the beginning and at the end of the 30-day experimental period. Starvation and T. weissflogii based diet poorly affected mussel growth and fatty acid composition which remained unchanged. On the contrary, the wheat germ-based diet increased the condition index and deeply affected the fatty acid profile of all lipid and phospholipid classes. The high dietary 18:2n-6 level drastically reduced tissue content of 20:4n-6, 20:5n-3 and 22:6n-3. The biosynthesis of Non Methylene Interrupted (NMI) dienoic fatty acid appeared to be insensitive to the high input of 16:1n-7 and 18:1n-9 respectively from diet B and C, and to the PUFA shortage of diet C. Nevertheless the two NMI trienoic derivatives, 20:3Δ5,11,14 and 22:3Δ7,13 16, were found higher in C with respect to other groups, presumably due to the high 18:2n-6 content of this diet.     

The degree of dietary fatty acid unsaturation affects torpor patterns and lipid composition of a hibernator

Diets rich in unsaturated and polyunsaturated fatty acids have a positive effect on mammalian torpor, whereas diets rich in saturated fatty acids have a negative effect. To determine whether the number of double bonds in dietary fatty acids are responsible for these alterations in torpor patterns, we investigated the effect of adding to the normal diet 5% pure fatty acids of identical chain length (C18) but a different number of double bonds (0, 1, or 2) on the pattern of hibernation of the yellow-pine chipmunk, Eutamias amoenus. The response of torpor bouts to a lowering of air temperature and the mean duration of torpor bouts at an air temperature of 0.5°C (stearic acid C18:0, 4.5±0.8 days, oleic acid C18:1, 8.6±0.5 days; linoleic acid C18:2, 8.5±0.7 days) differed among animals that were maintained on the three experimental diets. The mean minimum body temperatures (C18:0, +2.3±0.3°C; C18:1, +0.3±0.2°C; C18:2,-0.2±0.2°C), which torpid individuals defended by an increase in metabolic rate, and the metabolic rate of torpid animals also differed among diet groups. Moreover, diet-induced differences were observed in the composition of total lipid fatty acids from depot fat and the phospholipid fatty acids of cardiac mitochondria. For depot fat 7 of 13 and for heart mitochondria 7 of 14 of the identified fatty acids differed significantly among the three diet groups. Significant differences among diet groups were also observed for the sum of saturated, unsaturated and polyunsaturated fatty acids. These diet-induced alterations of body fatty acids were correlated with some of the diet-induced differences in variables of torpor. The results suggest that the degree of unsaturation of dietary fatty acids influences the composition of tissues and membranes which in turn may influence torpor patterns and thus survival of hibernation.Abbreviations bm body mass - T _a air temperature - T _b body temperature - FA fatty acid - MR metabolic rate - MUFA monounsaturated fatty acids - PUFA polyunsaturated fatty acids - VO₂ rate of oxygen consumption - SFA saturated fatty acids - UFA unsaturated fatty acids - UI unsaturation index - SNK Student-Newman-Keuls test     

Effect of maternal fat reserves on the fatty acid composition of sardine (Sardina pilchardus) oocytes

We compared the fatty acid (FA) composition of the muscle and gonads of female Iberian sardines with hydrated oocytes collected during the 2002/03 spawning season off southern Portugal (November and February) and off western Portugal (February). Sardine condition and total FA concentration in the muscle decreased between the two sampling dates, while the gonadosomatic index was similar between samples. Total monounsaturated FA concentrations in sardine gonads were different for the three samples while saturated and polyunsaturated FA concentrations were similar. Significant linear relations were found between FA concentrations in female muscle and oocytes, including eicosapentaenoic acid (EPA; 20:5n − 3) and arachidonic acid (AA; 20:4n − 6), both being essential for normal larval development. The concentration of docosahexaenoic acid (DHA; 22:6n − 3) in oocytes was independent on muscle concentration, probably resulting from its selective transfer to the oocytes. The EPA/DHA ratio was highly conserved in sardine tissues, while DHA/AA and EPA/AA ratios varied significantly between samples. These results indicate that the FA content of eggs produced by sardines varies throughout the spawning season, egg FA concentrations decreasing as females lose condition, and FA composition also shows spatial variability. Both types of variability may have a significant impact on egg quality, particularly on the amount of reserves available to larvae affecting their resistance to starvation, and the appropriate FA composition required for normal growth.     

Changes in fatty acid composition in Pseudomonas putida and Pseudomonas stutzeri during naphthalene degradation

The effects of naphthalene on the whole cell-derived fatty acid composition of Pseudomonas putida and Pseudomonas stutzeri during naphthalene degradation were investigated. These strains differed in their abilities to degrade naphthalene and in 1,2-catechol dioxygenase activities. The cells of both strains reacted to the addition of naphthalene with an increase in the saturated/unsaturated ratio. The dynamic changes comprised also alterations in the percentage of hydroxy, cyclopropane and branched fatty acids. Upon the exposure of naphthalene, new fatty acids were detected.     

Lipid and fatty acid composition of striped bass (Morone saxatilis) larvae during development

Changes in lipid class, fatty acid composition, protein, and dry and wet weights of fertilized eggs and developing larvae of striped bass (Morone saxatilis) fed with the live food, Artemia, were investigated. A decrease of wet and dry weights and moisture was observed at the beginning of the larval stage. Larvae regained the original moisture level, and wet and dry weights increased steadily after feeding. Total lipids decreased from 190 μg/egg in fertilized eggs to 151 μg/egg during hatching and increased after feeding. When total lipid contents were expressed as a percentage of larval dry weight, a decline of lipid did not occur until after feeding. Total protein, on the other hand, increased right after feeding, but there was some variation between days. Polar lipids increased significantly from 20 μg/egg at the egg stage to 199 μg/larva at 26 days post-hatching (DPH), 2 days before the onset of metamorphosis, while neutral lipids declined from 175 μg/egg to 80 μg/larva during the same time period. Wax/steryl esters decreased from 150 μg/egg in fertilized eggs to 32 μg/larva at 26 DPH. Triacylglycerols dropped from 21 μg/egg to 15 μg/larva before feeding and increased gradually after feeding. In contrast, the level of cholesterol increased 2–3-fold. There was a significant increase of phospholipids, particularly phosphatidylcholine in larvae after feeding. The fatty acid composition of fish larvae was significantly influenced by the diet, Artemia. There was an indication of catabolism of endogenous eicosapentaenoic and docosahexaenoic acids during metamorphosis.     

Fitness of juvenile lizards depends on seasonal timing of hatching,not offspring body size

To understand how selection shapes life-history traits, we need information on the manner in which offspring phenotypes influence fitness. Life-history allocation models typically assume that “bigger offspring are better”, but field data paint a more complex picture: larger offspring size sometimes enhances fitness, and sometimes not. Additionally, higher survival and faster growth of larger offspring might be due to indirect maternal effects (e.g., mothers allocate hormones or nutrients differently to different-sized eggs), and not to offspring size per se. Alternative factors, such as seasonal timing of hatching, may be more important. We examined these issues using 419 eggs from captive jacky dragon lizards (Amphibolurus muricatus). The mothers were maintained under standardized conditions to minimize variance in thermal and nutritional history, and the eggs were incubated under controlled conditions to minimize variance in offspring phenotypes due to incubation temperature and moisture. We reduced the size of half the eggs (and, thus, the size of the resultant hatchlings) from each clutch by yolk extraction. The hatchlings were marked and released at a field site over a 3-month period, with regular recapture surveys to measure growth and survival under natural conditions. Growth rates and survival were strongly enhanced by early-season hatching, but were not affected by hatchling body size.