Energy reserves and metabolic expenditures of monarch butterflies overwintering in southern California

Abstract. 1. Energetic expenditure and predicted requirements for overwintering metabolism were determined for monarch butterflies ( Danaus plexippus L.) in southern California.
2. Fat content of butterflies declined steadily from a maximum of 71% lean dry weight in late November to a minimum of 36% lean dry weight in late January. The energy expenditure measured by fat depletion over a 61 day period from 24 November to 25 January was 26.05 joules per day.
3. Butterflies were generally the same temperature as the air at any time they were inactive, whether they were part of a large cluster or roosting solitarily.
4. Oxygen consumption of butterflies increased in a curvilinear fashion with increasing air temperature. Thus, the predicted metabolic requirements for an inactive butterfly during their quiescent period from late November to late January was 30.32 joules per day.
5. In contrast to the steady depletion of fat reserves during their quiescent period in December and January, low and stable fat levels of butterflies in late February coincide with high levels of flight activity, mating and emigration of females from the colony.
6. Progressive tightening of the energy balance due to increasing nocturnal temperatures from northern to southern California coastal areas may limit the southern distribution and duration of overwintering aggregations.     

Genome-wide association study identifies quantitative trait loci regions involved in muscle acidic profile in Large White heavy pigs

The widespread use of genome-wide association studies resulted in the discovery of genomic regions associated with fatty acid (FA) composition in different porcine tissues, but little information exists about the genes involved in FA composition of meat obtained from heavy pigs selected for the production of Italian dry-cured hams. To this objective, we genotyped with a single nucleotide polymorphism (SNP) panel 795 Italian Large White heavy pigs to identify the markers and genomic regions associated with Semimembranosus muscle FA profile. Heritability estimates for intramuscular fat FA profile were of low-to-moderate magnitude, suggesting that these traits may be improved with genomic selection. On the whole, 45 SNPs were significantly associated with 14 FAs, and 4 of them (ALGA008109, ALGA0081097, CASI0010164 and SIRI0000267) were associated with more than 1 FA. The palmitoleic : palmitic and oleic : stearic ratios displayed the highest number of significant markers and the most significant associations (Bonferroni adjusted P < 5.00E−07). Of particular interest, the palmitoleic : palmitic ratio was strongly associated with markers located at 111 to 114 Mb on chromosome 14, in the same chromosomal region where Stearoyl-CoA desaturase Δ9 (SCD) gene is located. Several significant chromosomal regions were found; some of them harbour key genes playing pivotal roles in FA desaturation and elongation, such as SCD and some members of the Elongation of Very Long-Chain FA (ELOVL) gene family. The results suggest that the identification of causal mutations in these regions may provide a set of markers useful for selection schemes aimed at improving FA composition in pork products.     

In vivo study of metabolic dynamics and heterogeneity in brown and beige fat by label‐free multiphoton redox and fluorescence lifetime microscopy

In this work, the metabolic characteristics of adipose tissues in live mouse model were investigated using a multiphoton redox ratio and fluorescence lifetime imaging technology. By analyzing the intrinsic fluorescence of metabolic coenzymes, we measured the optical redox ratios of adipocytes in vivo and studied their responses to thermogenesis. The fluorescence lifetime imaging further revealed changes in protein bindings of metabolic coenzymes in the adipocytes during thermogenesis. Our study uncovered significant heterogeneity in the cellular structures and metabolic characteristics of thermogenic adipocytes in brown and beige fat. Subgroups of brown and beige adipocytes were identified based on the distinct lipid size distributions, redox ratios, fluorescence lifetimes and thermogenic capacities. The results of our study show that this label‐free imaging technique can shed new light on in vivo study of metabolic dynamics and heterogeneity of adipose tissues in live organisms.     

Endogenous retroviruses promote homeostatic and inflammatory responses to the microbiota

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Tumor-derived MMPs regulate cachexia in a Drosophila cancer model

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Stromal vascular fraction cells plus sustained release VEGF/Ang-1-PLGA microspheres improve fat graft survival in mice

Autologous fat transplantation is increasingly applied in plastic and reconstructive surgery. Stromal vascular fraction cells (SVFs) combined with angiogenic factors, such as VEGF (vascular endothelial growth factor A) and Ang-1 (angiogenin-1), can improve angiogenesis, which is a critical factor for graft survival. However, direct transplant with such a mixture is insufficient owing to the short half-life of angiogenic factors. In this study, we evaluated whether a double sustained release system of VEGF/ANG-1-PLGA (poly (lactic-co-glycolic acid)) microspheres plus SVFs can improve angiogenesis and graft survival after autologous fat transplantation. VEGF/ANG-1-PLGA-sustained release microspheres were fabricated by a modified double emulsion–solvent evaporation technique. Human aspirated fat was mixed with SVF suspension plus VEGF/ANG-1 sustained release microspheres (Group C), SVF suspension (Group B) alone, or Dulbecco’s modified Eagle’s medium as the control (Group A). Eighteen immunocompromised nude mice were injected with these three mixtures subcutaneously at random positions. After 8 weeks, the mean volume of grafts was greater in the SVFs plus VEGF/ANG-1-PLGA group than in the control and SVFs groups (1.08 ± 0.069 ml vs. 0.62 ± 0.036 ml, and 0.83 ± 0.059 ml, respectively). Histological assessments showed that lower fibrosis, but greater microvascular density in the SVFs plus VEGF/ANG-1-PLGA group than in the other groups, though the SVFs group also had an appropriate capillary density and reduced fibrosis. Our findings indicate that SVFs plus VEGF/ANG-1-PLGA-sustained release microspheres can improve angiogenesis and graft survival after autologous fat transplantation.     

The effect of starvation on haemolymph metabolites,fat body and ovarian development in Oxya japonica (Acrididae: Orthoptera)

Haemolymph volume does not change significantly during 96 hr of starvation. Haemolymph and fat body metabolites are depleted significantly in insects denied food for 96 hr. The percentage of oöcyte resorption is increased considerably by starvation. Differences in the utilization of lipid and protein under conditions of starvation between adult Oxya and adult locusts may be attributed to the migratory habit of the latter.     

Comparing the physiological effects and function of larval feeding in closely‐related endoparasitoids (Braconidae: Microgastrinae)

Abstract The larvae of most endoparasitoid wasps consume virtually all host tissues before pupation. However, in some clades, the parasitoid larvae primarily consume haemolymph and fat body and emerge through the side of the host, which remains alive and active for up to several days. The evolutionary significance of this host‐usage strategy has attracted attention in recent years. Recent empirical studies suggest that the surviving larva guards the parasitoid broods against natural enemies such as predators and hyperparasitoids. Known as the ‘usurpation hypothesis’, the surviving larvae bite, regurgitate fluids from the gut, and thrash the head capsule when disturbed. In the present study, the ‘usurpation hypothesis’ is tested in the association involving Manduca sexta, its parasitoid Cotesia congregata, and a secondary hyperparasitoid Lysibia nana. Percentage parasitoid survival is higher and hyperparasitism lower when cocoons of C. congregata are attached to the dorsum of M. sexta caterpillars. Fat body contents in several associations involving solitary and gregarious parasitoids feeding on haemolymph and fat body are also compared. The amount of fat body retained in parasitized caterpillars varies considerably from one association to another. In M. sexta and Pieris brassicae, considerable amounts of fat body remain after parasitoid emergence whereas, in Cotesia kariyai and Cotesia rufricus, virtually all of the fat body is consumed by the parsasitoid larvae. The length of post‐egression survival of parasitized caterpillars differs considerably in several tested associations. In Pseudeletia separata, most larvae die within a few hours of parasitoid emergence whereas, in M. sexta, parasitized larvae live up to 2 weeks after parasitoid emergence. Larvae in other associations parasitized by gregarious and solitary endoparasitoids live for intermediate periods. The results are discussed in relation to the adaptive significance of different feeding strategies of immature parasitoids and of the costs and benefits of retaining the parasitized caterpillar in close proximity with the parasitoid cocoons.     

Exercise training increases hepatic endoplasmic reticulum (er) stress protein expression in MTP‐inhibited high‐fat fed rats

The purpose of the study was: (1) to determine the effects of microsomal triglyceride transfer protein (MTP) inhibition on endoplasmic reticulum (ER) stress in liver, and (2) to determine if this response is altered in exercise‐trained rats. Female Sprague‐Dawley rats (6 weeks) fed either a standard (SD) or a high‐saturated fat (HF; 43% as energy) diet were trained (Tr) or kept sedentary (Sed) for 6 week. Exercise training consisted of continuous running on a motor‐driven rodent treadmill 5 times/week. Ten days before the end of these interventions, rats were administrated (ip) daily a MTP inhibitor (MTPX) or a placebo (P). MTPX injection resulted in a large (p < 0.01) liver triacylglycerol (TAG) accumulation in SD and HF‐fed rats (～200 mg g^?1), irrespective of the training status, while plasma TAG levels were largely (～80%) decreased (p < 0.01). MTPX injection in HF but not in SD‐fed animals resulted in an increase in BiP/GRP78, ATF6, PERK, and XBP‐1 mRNA levels, (p < 0.01) indicating an increase in the unfolding protein response (UPR) to ER stress. Interestingly, exercise training in rats fed the HF diet resulted in a further increase in BiP/GRP78 and XBP‐1 mRNA levels in MTPX animals (p < 0.01). It is concluded that: (1) ER stress induced by MTPX occurs only in HF‐fed rats despite the fact that liver TAG levels were largely increased in both dietary models; (2) the increase in gene expression of UPR markers with training may constitute a protective mechanism against ER stress in liver. Copyright © 2010 John Wiley & Sons, Ltd.