Effects of adult-derived carbohydrates, amino acids and micronutrients on female reproduction in a fruit-feeding butterfly

It is generally believed that butterflies (and other holometabolous insects) rely primarily on reserves accumulated during the larval stage for reproduction, whereas the carbohydrate-rich adult diet is thought to mainly cover energy requirements. In at least some species though, realization of the full reproductive potential is extensively affected by post-eclosion nutrition. While the importance of carbohydrates is fairly well understood, the role of adult-derived amino acids and micronutrients is controversial and largely unknown, respectively. We here focus on the effects of different adult diets on female reproduction in the tropical, fruit-feeding butterfly Bicyclus anynana (Nymphalidae). Carbohydrates were the most important adult-derived nutrients affecting reproduction. Adding amino acids, vitamins or minerals to sucrose-based solutions did not yield a reproductive output equivalent to that of fruit-fed females, which showed the highest performance throughout. This suggests that either not yet identified compounds of fruit substantially contribute to reproduction, or that resource congruence (the use of nutrient types in a specified ratio) rather than any specific nutrient component is of key importance. Apart from adult income, realized fecundity depended on egg size and longevity, with the former dominating when dietary quality was low, but the latter when quality was high. Thus, the egg size-number trade-off seems to be affected by female nutrition.     

Order from disorder, corralling cholesterol with chaotic lipids. The role of polyunsaturated lipids in membrane raft formation

A myriad of health benefits including the prevention of cancer and heart disease accompanies consumption of polyunsaturated fatty acids (PUFA). Of special importance is the omega-3-PUFA docosahexaenoic acid (DHA), with 22 carbons and six double bonds that constitute the most highly unsaturated fatty acid naturally occurring. Our experiments target the membrane as a likely site of action and focus upon the interaction of cholesterol with PUFA-containing phospholipids. They support the idea that steric incompatibility of the rigid steroid moiety for highly disordered PUFA chains promotes lateral segregation of lipids into PUFA-rich/sterol-poor and PUFA-poor/sterol-rich regions. Solid state 2H NMR and X-ray diffraction demonstrate that the solubility of cholesterol is low in polyunsaturated bilayers. In mixed membranes of phosphatidylethanolamine (PE) with the lipid raft-forming molecules sphingomyelin (SM) and cholesterol, diminished affinity of the sterol for 1-[2H31]palmitoyl-2-docosahexaenoylphosphatidylethanolamine ([2H31]16:0-22:6PE) relative to 1-[2H31]palmitoyl-2-oleoylphosphatidylethanolamine ([2H31]16:0-18:1PE) is identified by 2H NMR order parameters. Here, lies the origin of a potential biological advantage of the relatively modest increase in PUFA content of plasma membranes that would be conferred by dietary supplementation. We hypothesize that the enhanced propensity to form SM-/cholesterol-rich rafts as well as PUFA-rich/cholesterol-poor microdomains would modify the function of proteins for which these respective regions provide a platform.     

Effects of the juvenile hormone mimic pyriproxyfen on female reproduction and longevity in the butterfly Bicyclus anynana

Female Bicyclus anynana butterflies given pyriproxyfen, a mimic of juvenile hormone, exhibited increased egg‐laying rates and early fecundity, but reduced longevity compared with control animals. Thus, pyriproxyfen application yielded antagonistic effects on different components of fitness, possibly demonstrating a juvenile hormone‐mediated trade‐off between present and future reproduction. Lifetime fecundity and egg size, however, showed no consistent response to pyriproxyfen, with lifetime fecundity being increased or decreased and egg size being reduced in one out of four experiments only. Females were most sensitive to pyriproxyfen around the onset of oviposition, coinciding with naturally increasing juvenile hormone titers in other Lepidoptera. Amounts between 1 and 10 µg pyriproxyfen were found to be effective, with, however, pronounced differences among experiments. This is attributed to differences in assay conditions. High pyriproxyfen concentrations (100 µg) as well as repeated applications of smaller amounts did not affect reproductive traits, but tended to reduce longevity.     

Effects of maternal age and adult diet on egg weight in the butterfly Euphydryas editha

ABSTRACT. 1. Euphydryas editha (Boisduval) (Nymphalidae) butterflies exhibited no consistent pattern of change in egg weight over their lifetimes. This was the case for captive butterflies fed diets containing sugars and amino acids, for butterflies fed diets containing only sugar, and for those left completely at liberty in their natural habitats between ovipositions.
2. Two aspects of these results conflict with the findings of a previous study on the same subspecies. First, the previous study found that egg weight decreased with increasing maternal age. Second, this decrease was mitigated by addition of amino acids to the adult diet.
3. We accept the findings of these previous workers that egg weight decreased with maternal age under their laboratory conditions. The discrepancy between their data and ours is likely to stem from the more natural conditions under which our insects were kept. Our own data from captive insects are not distinguishable from our field data.
4. These results suggest that declines of egg weight with maternal age found in studies of other insects may also result from the artificial nature of laboratory conditions. We question whether such declines are general.
5. We suggest that the second discrepancy between the two sets of work (effects of amino acids) stems from a design problem in the previous study.     

Effect of dietary lipids on plasma fatty acid profiles and prostaglandin and leptin production in gilthead seabream (Sparus aurata)

The aim of this study was to investigate the effects of different levels of substitution of fish oil by vegetable oils rich in oleic, linoleic and linolenic acids on gilthead seabream plasma and leukocyte fatty acid compositions and prostaglandin (PG) and leptin production. Juvenile seabream of 24 g initial body mass were fed four iso-energetic and iso-proteic experimental diets for 281 days. Fatty acid composition of plasma lipids was markedly affected by the inclusion of vegetable oils (VO). ARA (arachidonate), EPA (eicosapentaenoate) and DHA (docosahexaenoate) were preferentially incorporated into polar lipids of plasma, and DHGLA (di-homogammalinoleate) accumulated with increased vegetable oil inclusion. Dietary treatments resulted in alterations of DHGLA/ARA ratios, but not ARA/EPA. ARA-derived PGE₂ production in plasma was not affected by vegetable oils, in agreement with similar eicosanoid precursor ratio (ARA/EPA) in leukocytes total lipids and plasma phospholipids among fish fed with the different dietary treatments. Feeding vegetable oils leads to a decrease in plasma EPA which in turn reduced plasma PGE₃ concentration. Moreover, PGE₃ was the major prostaglandin produced in plasma of fish fed fish oil based diet. Such findings point out the importance of EPA as a precursor of prostaglandins in marine fish, at least for the correct function of the blood cells, and correlates well with the predominant role of this fatty acid in immune regulation in this species. A negative correlation was found between plasma PGE₂ and leptin plasma concentration, suggesting that circulating levels of leptin may act as a metabolic signal modulating PGE₂ release. The present study has shown that increased inclusion of vegetable oils in diet for gilthead seabream may profoundly affect the fatty acid composition of plasma and leukocytes, specially HUFA (highly unsaturated fatty acids), and consequently the production of PGE₃, which can be a major PG in plasma. Alteration in the amount and type of PG produced can be at least partially responsible for the changes in the immune system and health parameters of fish fed diets with high inclusion of VO.     

Effects of temperature on reproductive output, egg provisioning, juvenile hormone and vitellogenin titres in the butterfly Bicyclus anynana

Environmentally induced phenotypic plasticity is common in nature. Hormones, affecting multiple traits and signaling to a variety of distant target tissues, provide a mechanistic link between environments, genes and trait expression, and may therefore well be involved in the regulation phenotypic plasticity. Here, we investigate whether in the tropical butterfly Bicyclus anynana temperature-mediated plasticity in egg size and number, with fewer but larger eggs produced at lower temperatures and vice versa, is under control of juvenile hormone, and whether different temperatures cause differences in egg composition. Female B. anynana butterflies showed the expected response to temperature, however, we found no evidence for an involvement of juvenile hormone. Neither haemolymph JH II and JH III titres nor vitellogenin levels differed across temperatures. The smaller eggs produced at the higher temperature contained relatively higher amounts of water, free carbohydrates and proteins, but relatively lower amounts of lipids. While these smaller eggs had a lower absolute energy content, total reproductive investment was higher at the higher temperature (due to a higher fecundity). Overall, our study indicates that temperature-mediated plasticity in reproduction in B. anynana is mechanistically related to a biophysical model, with oocyte production (differentiation) and oocyte growth (vitellogenesis) having differential temperature sensitivities.     

Review on the role of dietary zinc in poultry nutrition, immunity, and reproduction

Zinc is an important nutrient in animal metabolism. In poultry, zinc serves not only as a nutrient but can also be used as a dietary supplement to manipulate the reproductive system of the bird. This article summarizes the general biochemistry, physiology, and nutritional aspects of zinc metabolism to provide a brief overview on what is known regarding zinc. The potential role of zinc in poultry immune response, Salmonella infection, and molting are emphasized.     

Eicosapentaenoic acid in the treatment of schizophrenia and depression: rationale and preliminary double-blind clinical trial results

It has been hypothesised that polyunsaturated fatty acids (PUFA) play an important role in the aetiology of schizophrenia and depression. Evidence supporting this hypothesis for schizophrenia includes abnormal brain phospholipid turnover shown by 31P Magnetic Resonance Spectroscopy, increased levels of phospholipase A2, reduced niacin skin flush response, abnormal electroretinogram, and reduced cell membrane levels of n-3 and n-6 PUFA. In depression, there is strong epidemiological evidence that fish consumption reduces risk of becoming depressed and evidence that cell membrane levels of n-3 PUFA are reduced. Four out of five placebo-controlled double- blind trials of eicosapentaenoic acid (EPA) in the treatment of schizophrenia have given positive findings. In depression, two placebo-controlled trials have shown a strong therapeutic effect of ethyl-EPA added to existing medication. The mode of action of EPA is currently not known, but recent evidence suggests that arachidonic acid (AA) if of particular importance in schizophrenia and that clinical improvement in schizophrenic patients using EPA treatment correlates with changes in AA.     

Inhibition of astroglial glutamate transport by polyunsaturated fatty acids: Evidence for a signalling role of docosahexaenoic acid

Brain cells are especially rich in polyunsaturated fatty acids (PUFA), mainly the n-3 PUFA docosahexaenoic acid (DHA) and the n-6 PUFA arachidonic acid (AA). They are released from membranes by PLA2 during neurotransmission, and may regulate glutamate uptake by astroglia, involved in controlling glutamatergic transmission. AA has been shown to inhibit glutamate transport in several model systems, but the contribution of DHA is less clear and has not been evaluated in astrocytes. Because the high DHA content of brain membranes is essential for brain function, we investigated the role of DHA in the regulation of astroglial glutamate transport.We evaluated the actions of DHA and AA using cultured rat astrocytes and suspensions of rat brain membranes (P1 fractions). DHA reduced d-[³H]aspartate uptake by cultured astrocytes and cortical membrane suspensions, while AA did not. This also occurred in astrocytes enriched with α-tocopherol, indicating that it was not due to peroxidation products. The reduction of d-[³H]aspartate uptake by DHA did not involve any change in the concentrations of membrane-associated astroglial glutamate transporters (GLAST and GLT-1), suggesting that DHA reduced the activity of the transporters. In contrast with the inhibition induced by free-DHA, we found no effect of membrane-bound DHA on d-[³H]aspartate uptake. Indeed, the uptake was similar in astrocytes with varying amount of DHA in their membrane (induced by long-term supplementation with DHA or AA). Therefore, DHA reduces glutamate uptake through a signal-like effect but not through changes in the PUFA composition of the astrocyte membranes. Also, reactive astrocytes, induced by a medium supplement (G5), were insensitive to DHA. This suggests that DHA regulates synaptic glutamate under basal condition but does not impair glutamate scavenging under reactive conditions.These results indicate that DHA slows astroglial glutamate transport via a specific signal-like effect, and may thus be a physiological synaptic regulator.     

Energetics of embryonic development: effects of temperature on egg and hatchling composition in a butterfly

Phenotypic plasticity may allow an organism to adjust its phenotype to environmental needs. However, little is known about environmental effects on offspring biochemical composition and turnover rates, including energy budgets and developmental costs. Using the tropical butterfly Bicyclus anynana and employing a full-factorial design with two oviposition and two developmental temperatures, we explore the consequences of temperature variation on egg and hatchling composition, and the associated use and turnover of energy and egg compounds. At the lower temperature, larger but fewer eggs were produced. Larger egg sizes were achieved by provisioning these eggs with larger quantities of all compounds investigated (and thus more energy), whilst relative egg composition was rather similar to that of smaller eggs laid at the higher temperature. Turnover rates during embryonic development differed across developmental temperatures, suggesting an emphasis on hatchling quality (i.e. protein content) at the more stressful lower temperature, but on storage reserves (i.e. lipids) at the higher temperature. These differences may represent adaptive maternal effects. Embryonic development was much more efficient at the lower temperature, providing a possible mechanism underlying the temperature-size rule.     

Experimental manipulation of egg quality in chickens: influence of albumen and yolk on the size and body composition of near-term embryos in a precocial bird

The importance of avian egg components in the determination of hatchling size and quality has yet to be fully evaluated. In the first experiment, 20% of the albumen and/or the yolk was removed from chicken eggs to determine the impact of each egg component on metabolism and various size measures in near-term embryos. Results show that metabolic rate, dry body mass, and internal organ mass are largely independent of egg composition. Removal of albumen resulted in a decrease in wet body mass corresponding to decreases in water content in the body and the yolk sac, and decreased tibiotarsus length. Removal of yolk resulted in no change in body mass, but decreases in both wet and dry yolk sac mass. In a second experiment, removal of 15% of either egg component led to reductions in hatchling mass similar to those observed in whole near-term embryos. Albumen, as the primary source of water in the egg, is the primary determinant of hatchling size and may influence hatchling success through size-related limiting factors. Differences in yolk content may influence neonatal quality as a nutritional supplement, but seem not to result in greater tissue formation during embryonic development. Accepted: 2 September 1997     

The influence of nymphal and adult dietary protein on food intake and reproduction in female brown-banded cockroaches

Female brown-banded cockroaches, Supella longipalpa (F.) (Dictyoptera: Blattellidae), failed to elevate consumption rates when fed a 5% protein diet compared with females fed either 25% protein or commercial rat food. Adult performance was directly influenced by dietary protein level: Females fed 65% protein died rapidly, while in females fed 5% protein feeding and reproductive rates were reduced after production of three oothecae. In females fed a low protein diet as both late instar nymphs and as adults, mating was delayed and they required more time to form oothecae than females switched to 25% protein as adults. The role of nymphal reserves in adult reproduction is discussed.

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Résumé La consommation et la reproduction de S. longipalpa ont été examinées lors de la consommation d'aliment standard pour rat et de régimes artificiels contenant 5, 25 et 65% de protéines. Les femelles élevées sur régime à 5% de protéines ne consomment pas plus et leur reproduction est significativement inférieure à celle de femelles élevées sur aliment standard ou à 25% de protéines; après la production de 3 oothèques, la reproduction de ces femelles se ralentit, leur consommation diminue et les oothèques deviennent plus petites que celles des femelles élevées sur un régime à 25% de protéines. Nous supposons que les premiers cycles reproductifs de ces femelles ont été assurés avec les réserves accumulées pendant la vie larvaire. Les femelles alimentées sur régime à 5% de protéines à la fois pendant le dernier stade larvaire et pendant la vie imaginale ont besoin de beaucoup plus de temps pour s'accoupler et pour produire des oothèques que les femelles alimentées sur régime à 5% pendant le dernier stade larvaire et transférées adultes sur un régime à 25% de protéines. Ainsi, les réserves larvaires sont une ressource importante améliorant la reproduction des adultes ayant un régime pauvre en protéines. Cependant, le passé alimentaire larvaire a peu d'effet sur la reproduction des adultes alimentés convenablement.

     

Perspectives on the use of marine and freshwater hydrobiont oils for development of drug delivery systems

Marine foods represent a unique source of poly-unsaturated fatty acids (PUFA) of the omega-3 (n-3) family. Today it is generally accepted that fish oil is important in a healthy and balanced omnivorous human diet. This favorable health perception of fish oil is however troubled by the high level of PUFA oxidation and low absorption in the gastro-intestinal tract. In this work we present and described various types of delivery systems which are used to improve PUFA and fish oil availability and oxidative stability.     

Sexual conflict and cooperation in butterfly reproduction: a comparative study of polyandry and female fitness

Most butterfly species can be characterized as capital breeders, meaning that reproductive output is strongly coupled to the amount of resources they have procured during the larval stage. Accordingly, female fecundity is generally correlated with female mass, both within and across species. However, the females of some species can be partly characterized as income breeders, in the sense that their reproductive output is dependent not only on larval-derived capital but also on resources acquired during the adult stage. These adult resources can be derived from female feeding or from male-transferred nuptial gifts. Recent studies on the within-species effects of multiple matings on female fitness show that females generally gain directly from multiple matings in terms of increased lifetime offspring production. Here, we test whether the positive effects of multiple mating on female fitness also hold at a comparative level, by conducting a laboratory study of female reproductive output in eight pierid species that differ in life-time female mating frequency. Female reproductive output, measured as cumulative egg mass divided by female mass, increased significantly with polyandry (r = 0.942, p < 0.001), demonstrating that the positive effect of mating rate on female reproductive fitness also holds between species. The positive effect of male nutrient contribution is substantial, and the per capita reproductive output is more than twice as high in the most polyandrous species as in the most monandrous ones. Hence, the positive net effect of the ejaculates is highly substantial, although males and females can have sexual interests that run counter to each other, setting the stage for sexually antagonistic coevolution, so that the various component parts of the male ejaculate-sperm, nutrients, anti-aphrodisiacs, and gonadotrophic hormones-may each correspond to a separate conflict-cooperation balance between the sexes. Two scenarios for the evolution of nuptial gifts in butterflies are discussed, one arguing that variation in larval food is the underlying factor and the other arguing that sexually antagonistic coevolution is the driving force. The two views are complementary rather than mutually exclusive, although the former hypothesis predicts that variation in female mating rate depends on variation in larval food availability, whereas the latter suggests that variation in female mating rate between species results from species-specific idiosyncrasies.     

The yeast plasma membrane ATP binding cassette (ABC) transporter Aus1: purification, characterization, and the effect of lipids on its activity

The ATP binding cassette (ABC) transporter Aus1 is expressed under anaerobic growth conditions at the plasma membrane of the yeast Saccharomyces cerevisiae and is required for sterol uptake. These observations suggest that Aus1 promotes the translocation of sterols across membranes, but the precise transport mechanism has yet to be identified. In this study, an extraction and purification procedure was developed to characterize the Aus1 transporter. The detergent-solubilized protein was able to bind and hydrolyze ATP. Mutagenesis of the conserved lysine to methionine in the Walker A motif abolished ATP hydrolysis. Likewise, ATP hydrolysis was inhibited by classical inhibitors of ABC transporters. Upon reconstitution into proteoliposomes, the ATPase activity of Aus1 was specifically stimulated by phosphatidylserine (PS) in a stereoselective manner. We also found that Aus1-dependent sterol uptake, but not Aus1 expression and trafficking to the plasma membrane, was affected by changes in cellular PS levels. These results suggest a direct interaction between Aus1 and PS that is critical for the activity of the transporter.     

Effects of acetyl-L-carnitine on the formation of fatty acid ethyl esters in brain and peripheral organs after short-term ethanol administration in rat

Increasing evidence suggests that Fatty acid ethyl esters (FAEE) play a central role in ethanol induced organ damage. In the current study we measured FAEE formation in rats after short-term oral administration of ethanol, in the presence and absence of pre-treatment with acetyl-L-carnitine. Ethanol treatment caused a significant increase in the levels of FAEE, particularly in the brain and heart, but also in the kidney and liver. Increases in FAEE were associated with a significant increase in FAEE synthase activity, GSH transferase activity, and lipid hydroperoxide levels. Pre-treatment with acetyl-L-carnitine resulted in a significant reduction of FAEE accumulation, decrease in FAEE synthase and GSH transferase activities, and lipid hydroperoxide levels. Administration of acetyl-L-carnitine greatly reduced the metabolic abnormalities due to non-oxidative ethanol metabolism, through an increment in lipid metabolism/turnover and by the modulation of the activities of enzymes associated with FAEE synthesis. These results suggest a potentially important pharmacological role for acetyl-L-carnitine in the prevention of alcohol-induced cellular damage.     

Coexisting role of fasting or feeding and dietary lipids in the control of gene expression of enzymes involved in the synthesis of saturated, monounsaturated and polyunsaturated fatty acids

In the liver, maintaining lipid homeostasis is regulated by physiological and exogenous factors. These lipids are synthesized by Fasn, elongases and desaturases. Interactions in an organism among these factors are quite complex and, to date, relatively little is known about them. The aim of this study was to evaluate the coexisting role of physiological (insulin, fasting and feeding) and exogenous (dietary lipids) factors in the control of gene expression of Fasn, elongases and desaturases via Srebf-1c in liver from rats. Gene expression of encoding enzymes for fatty acid synthesis and fatty acid composition was evaluated in liver from rats in fasting and feeding (at 30, 60, 90 and 120 min after feeding) when food intake (adequate or high-lipid diet) was synchronized to a restricted period of 7h. Fasn, Scd and Fads2 were induced during 120 min after initial feeding in both dietary groups. This induction may be activated in part by insulin via Srebf-1c. Also, we showed for the first time that Elovl7 may be regulated by insulin and dietary lipids. The failure to synthesize saturated and monounsaturated fatty acids is consistent with a downregulation of Fasn and Scd, respectively, by dietary lipids. A higher content of LC-PUFAs was observed due to a high expression of Elovl2 and Elovl5, although Fads2 was suppressed by dietary lipids. Therefore, elongases may have a mechanism that is Srebf-1c-independent. This study suggests that a high-lipid diet triggers, during 120 min after initial feeding, a tight coordination among de novo lipogenesis, elongation, and desaturation and may not always be regulated by Srebf-1c. Finally, upregulation by feeding (insulin) of Fasn, Scd, Fads2 and Srebf-1c is insufficient to compensate for the inhibitory effect of dietary lipids.     

EPR spectroscopy and electrospray ionization mass spectrometry reveal distinctive features of the iron site in leukocyte 12-lipoxygenase

The procedure for the expression and purification of recombinant porcine leukocyte 12-lipoxygenase using Escherichia coli [K.M. Richards, L.J. Marnett, Biochemistry 36 (1997) 6692-6699] was updated to make it possible to produce enough protein for physical measurements. Electrospray ionization tandem mass spectrometry confirmed the amino acid sequence. The redox properties of the cofactor iron site were examined by EPR spectroscopy at 25 K following treatment with a variety of fatty acid hydroperoxides. Combination of the enzyme in a stoichiometric ratio with the hydroperoxides led to a g4.3 signal in EPR spectra instead of the g6 signal characteristic of similarly treated soybean lipoxygenase-1. Native 12-lipoxygenase was also subjected to electrospray ionization mass spectrometry. There was evidence for loss of the mass of an iron atom from the protein as the pH was lowered from 5 to 4. Native ions in these samples indicated that iron was lost without the protein completely unfolding.     

Energetics of reproduction: consequences of divergent selection on egg size, food limitation, and female age for egg composition and reproductive effort in a butterfly

Using lines artificially selected on egg size and being subjected to a restricted and an unrestricted feeding treatment, we examined the relationships between egg size, egg number, egg composition, and reproductive investment in the butterfly Bicyclus anynana . Despite a successful manipulation of egg size, correlated responses to selection in larval time, pupal mass, pupal time, longevity, fecundity, or the amount of energy allocated to reproduction were virtually absent. Thus, there was no indication for an evolutionary link between offspring size and reproductive investment. Egg composition, in contrast, was affected by selection, with larger eggs containing relatively more lipid and water, but less protein and energy compared to smaller eggs. Hence, females producing large eggs did not have to sacrifice fecundity due to adjustments in egg composition. Food limitation per se caused only minor changes in egg composition, and there was no general reduction in egg provisioning with female age. The latter was restricted to food-limited females, whereas egg quality remained remarkably similar throughout the females' life in control groups. We conclude that neglecting changes in biochemical egg composition, depending on genetic background, food availability, and female age, may introduce substantial error when estimating reproductive effort, and may ultimately lead to invalid conclusions.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 91 , 403–418.