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The ultrastructure and ultracytochemistry of the basement membrane of the Galleria mellonella fat body.

The fat body lobes of Galleria mellonella are surrounded by basement membrane - a fine granular layer of connective tissue. This membrane has an affinity for ruthernium red. The results obtained after treatment of the fat body with neuraminidase, hyaluronidase, phospholipase C and proteolytic enzymes suggest that glycoproteins and phospholipoproteins are constituents of this basement membrane. The basement membrane also has the ability to bind concanavalin A-peroxidase, which is associated with the presence of mannoside residues.

Adipose Tissue

Hypothalamic function as related to body weight and body fat in anorexia nervosa.

Percentage body fat is predictive of the onset of menstruation at puberty. In anorexia nervosa a relationship between luteinizing hormone (LH) levels and percentage weight loss has been reported. In the current study the relationship of percentage body fat and of percentage weight loss to LH and LH reactivity was examined in anorexia nervosa. Fifteen women with anorexia nervosa were studied. The resting levels of LH were measured, and in seven of the subjects LH response to luteinizing hormone releasing hormone (LHRH) and clomiphene was tested. The increment in plasma LH was measured in response to a 100 microgram dose of LHRH, and also to a 5-day course of clomiphene 100 mg. The resting LH levels were found to correlate with percentage fat, body weight, and percentage weight loss. Correlations were also found between the response to either LHRH or clomiphene and percentage weight loss, percentage fat, and absolute body weight. Other pituitary hormones measured did not show a relationship to body fat or weight. It is concluded that in addition to being predictive of the onset of menstruation, percentage body fat is significantly related to resting LH and LH reactivity in anorexia nervosa. Although percentage body fat, percentage weight loss, and absolute body weight are all significant correlates of LH reactivity, we cannot at this time conclude that any one in particular is the superior.

Adipose Tissue

A fine structural survey of the development of the adult fat body of Leptinotarsa decemlineata.

The fat body of a female Colorado potato beetle, Leptinotarsa decemlineata, at adult ecdysis, contains a large number of protein granules which are composed of light and dark zones. Part of the light zone in some of these granules is believed to be urate. During the first two days after adult ecdysis, fat body development is not essentially different in females reared either under long- or short-day conditions. Protein granules and large vacuoles disappear and the first cell organelles are regenerated. The effect of the photoperiod on the histological structure of the fat is expressed after these events. In females reared under long-day conditions, the fat body becomes specialized for vitellogenin synthesis. Under short-day conditions, the fat body stores massive amounts of lipid until day 6 after adult ecdysis. Then the first electron-dense protein granules develop near the nucleus, and on day 10 the first autophagic vacuoles are seen. These structure changes are discussed in connection with the known biochemical properties of the adult faty body of Leptinotarsa.

Adipose Tissue

Cell remodeling in the fat body of an insect.

The fat body of the Lepidopteran, Calpodes ethlius, undergoes major functional changes during larval-adult metamorphosis. These changes occur in conjunction with extensive cell remodeling - a process whereby one population of cellular organelles is destroyed and replaced by another during development. Fat body organelles including mitochondria, microbodies, and RER are destroyed on a massive scale shortly before pupation (Locke and Collins, 1965; Locke and McMahon, 1971) a new populations of each are regenerated shortly after emergence of the adult. In addition, protein, lipid and RNA reserves formed shortly before pupation and multivesicular bodies formed shortly before emergence are secreted into the haemocoel during the first few days of adult life. Electron microscopic studies using tracer techniques, cytochemical and enzyme localization procedures, and sterological analyses have been undertaken to determine the time course and mechanism of organelle regeneration and the fate of reserves stored in the fat body.

Acid Phosphatase

Relationship between body fat mass, carbohydrate tolerance and IRI response during glucose infusion in subjects with early diabetes.

We have studied the interrelationship of total body fat mass, carbohydrate tolerance and IRI response in 17 non-obese and obese subjects, who were suspected of having early diabetes. We carried out an i.v. glucose infusion test consisting of a priming injection of 0.33 g/kg followed by constant glucose infusion of 12 mg/kg/min in all persons. Total body fat mass was estimated by the tritium dilution method. There was a positive correlation of body fat mass, fasting glucose concentration and blood glucose concentration at 150 min as well as a strong correlation between body fat mass and BG area 60--120 min as parameters of carbohydrate tolerance in all subjects, i.e. the degree of carbohyrate intolerance was directly related to the quantity of total body fat mass. A similar correlation was found when the non-obese and obese groups were analyzed separately. In neither group did total body fat mass correlate with parameters of IRI response. In obese subjects with pathological carbohydrate tolerance, however, a positive correlation of basal IRI concentration and total body fat mass was found. Furthermore, a close relation between basal IRI level and parameters of carbohydrate tolerance could be demonstrated in obese subjects. The present study failed to demonstrate any correlation of parameters of carbohydrate tolerance and glucose-induced IRI response in either group. Thus, the significant relationship between body fat mass and degree of carbohydrate intolerance indicates that body fat mass plays an important role in the disturbance of blood glucose homeostasis in early diabetes with and without obesity.

Adipose Tissue

Body composition in middle-aged women with special reference to the correlation between body fat mass and anthropometric data.

A variety of anthropometric measurements was made in a randomized population sample of middle-aged women in five age strata in whom body composition was estimated from total body potassium and total body water determined by whole body counting and isotope dilution technique, respectively. No significant differences with age were found for total body potassium or total body water. A significant age difference was found for body fat mass. Simple linear correlations between anthropometric variables and body fat mass estimates were found to be 0.90, 0.86, 0.77 for body weight, buttock circumference, and sum of triceps and subscapular skinfold thicknesses, respectively. Multiple regression analysis showed that these three variables accounted for 80 to 91% of the variation in body fat in the different age strata studied. Multiple regression equations for prediction of body fat from anthropometric variables are given. In about two-thirds of the subjects, the difference between predicted body fat mass and estimated body fat mass was found to be less than +/- 2.5 kg.

Adipose Tissue

Equations for estimating percentage of body fat in children 10--14 years old.

Measurements of the percentage of body fat (derived by underwater weighing), height, weight, and triceps skinfold thickness were determined for a volunteer sample of 214 children, 10--14 years old. The bivariate correlations, by sex, of percentage of body fat with five obesity indices are highest with the triceps skinfold and least with weight-height. Five sets of equations are presented for predicting percentage of body fat based on measurements of either height and weight, triceps skinfold, or height, weight, and triceps skinfold. Cumulative frequency distributions of the percentage of body fat (based on height, weight, and triceps skinfold) are shown by race and sex for a total community of 10- to 14-year olds.

Adipose Tissue

The influence of hemolymph-binding protein on juvenile hormone stability and distribution in Manduca sexta fat body and imaginal discs in vitro.

The wing discs and fat body of Manduca sexta larvae contain enzymes (i.e. carboxylesterase and epoxide hydratase) that can convert the C18 juvenile hormone (JH) to the acid, diol and acid diol. No evidence of oxidative degradation was noted. In vitro studies suggest that JH can be compartmentalized within the cells of the fat body where it is less accessible to degradative mechanisms. Experiments utilizing a hemolymph-binding protein fraction (BPF) in vitro with fat body and imaginal discs indicate that the BPF retards the uptake of JH by tissues and its subsequent degradation by tissue enzymes. BPF also appears to protect JH from degradation by enzymes released into the medium. By these mechanisms the insect can maintain elevated JH titers for relatively long periods. Binding protein may also keep JH in solution in the hemolymph allowing its rapid distribution throughout the insect. The data suggest that the binding protein plays a key role in maintaining juvenile hormone titers.

Adipose Tissue

Ecdysone-inducible functions of larval fat bodies in Drosophila.

Late in the third instar larval stage of Drosophila melanogaster, the titer of the steroid hormone ecdysone increases sharply. This increase is blocked in the temperature-sensitive mutant ecd(1) after a temperature shift from 20 degrees C to 29 degrees C. The mutant was used to prepare three samples of late third instar larvae with different titers of ecdysone; the titer was low in one sample because of an earlier temperature shift, high in a second sample because the larvae were subsequently transferred to ecdysone-supplemented food, and also high in a third sample that was kept at 20 degrees C, providing a control for normal development. The effect of the high titer of ecdysone on proteins of the larval fat bodies was examined by comparing two-dimensional gel electrophoresis patterns of total proteins in stained gels. There were proteins at five positions in the gels for the high-ecdysone samples that were not detected at the corresponding positions in the gel for the low-ecdysone sample. The effect of ecdysone on these proteins was further studied by injecting [(35)S]methionine into the larvae at both early and late third instar stages, in order to label proteins synthesized before and after the increase in ecdysone titer. The results indicate that ecdysone induces two major responses in the fat bodies; certain proteins that were synthesized earlier in the fat bodies and secreted into the hemolymph are incorporated back into the fat bodies, and other proteins are newly synthesized. Attempts to induce prematurely the synthesis of the new proteins by exposing early third instar larvae to exogenous ecdysone were unsuccessful, suggesting that development must proceed further before the fat bodies can respond to ecdysone. By in vitro translation of RNA isolated from fat bodies of low-and high-ecdysone samples of larvae, it was shown that ecdysone greatly increases the amount of translatable messenger RNA for one of the newly synthesized proteins. A clone of DNA complementary to the induced messenger RNA has been isolated from a population of lambda bacteriophage carrying segments of the Drosophila genome. Using the cloned DNA to measure amounts of complementary poly(A)-RNA in the fat bodies by DNA.RNA hybridization, we detected about 50 times more complementary poly(A)-RNA in the high-ecdysone sample of larvae than in the low-ecdysone sample. This finding provides direct evidence that ecdysone induces an increase in the amount of the messenger RNA. The ecdysone-induced appearance of a major messenger RNA in late third instar larval fat bodies represents a developmental response to ecdysone that appears to be gene-specific, tissue-specific, and stage-specific, and it has exceptionally favorable features for further molecular studies of the control of gene expression by a steroid hormone.

Adipose Tissue

Ultrastructural study of the neural fat-body system in the cockroach Periplaneta americana.

The neural fat-body system of the ventral nerve cord in the cockroach Periplaneta americana was studied with the light and electron microscopes. This adipose tissue surrounds the connectives and extends over the ganglia. The adipose cells typically contain numerous extremely large lipid inclusions, pleomorphic lysosomes, and tightly packed glycogen granules. The neural lamella consists of a thick inner layer rich in collagen fibers and a thin outer layer of granular material. At points where the fat body is attenuated, this granular layer is split and the outer lamina is reflected superficially to ensheath and apparently to anchor the fat body.

Adipose Tissue

Aerobic fitness and body fat of young British males entering the army.

Aerobic fitness and percent body fat were measured in a sample of 438 male Army recruits between the ages of 17 and 30 prior to the commencement of training. The sample came from all areas of England and Wales. Aerobic fitness, as represented by maximal oxygen uptake (VO2 max), was predicted from the Astrand submaximal bicycle heart rate test. Body fat was predicted from four skinfold measurements. Total group means +/- SD were: age, 19.5 +/- 2.5 years; VO2 max 41.7 +/- 8.3 ml/kg . min; and body fat, 14.5 +/- 4.8% of body weight. VO2 max varied with age, athletic participation and aptitude score. No relationship was found with occupation of parent, prior civilian occupation or smoking severity. When adjusted for methodological differences, VO2 max was slightly below similar Army entrants in Norway and the United States.

Adipose Tissue

The function of fat bodies in relation to the hypothalamo-hypophyseal-gonadal axis in the frog, Rana esculenta.

In this study the authors have tried to furnish experimental support for the importance of fat bodies in the normal functioning of the hypothalamo-hypophyseal-gonadal system of the male frog, Rana esculenta. These experiments have shown a hypothalamo-hypophyseal control of the mobilization of fat body contents, directly involved in the control of testicular activity. Furthermore it is proposed that the fat body contents are released into the testis through direct vascular contacts between the two organs. We suggest that the A1 cells (lactotrophs) and/or B2 cells (FSH-gonadotrops) of the pars distalis gonadotropins are incapable of stimulating the testis in the absence of fat bodies. In the light of these results a scheme has been put forward showing the position of fat bodies in the hypothalamo-hypophyseal-gonadal axis of the frog.

Adipose Tissue

Multi-omics unveils seasonal remodeling and metabolic crosstalk between testis and abdominal fat body in a non-amplexus stream frog Nanorana taihangnica (Anura: Dicroglossidae).

BACKGROUND: Energy allocation between reproduction and survival represents a fundamental life-history challenge for animals in seasonal environments. Using integrated transcriptomics and metabolomics, we investigated Nanorana taihangnica (Anura: Dicroglossidae), a non-amplexus stream frog endemic to China, to elucidate the seasonal morphological and molecular coordination between the testis and abdominal fat body. RESULTS: Morphological analysis showed that fat body adipocyte cross-sectional area minimized at the end of the breeding season but rapidly recovered thereafter, while testicular volume continued declining post-breeding and only recovered during the non-breeding period. During breeding season, multi-omics analyses revealed that the fat body enhanced fatty acid oxidation, upregulated histidine-carnosine metabolism, activated NAD+ metabolism and FOXO3-mediated antioxidative responses to mitigate metabolic stress, and regulated adipocyte survival and apoptosis via sphingolipid signaling. Seasonal testicular development was centrally regulated by the mTOR signaling pathway, whose activity integrated autophagy levels, NAD+ availability, and aspartate metabolism to coordinate spermatogonial proliferation and spermatogenesis. CONCLUSIONS: This study demonstrates that N. taihangnica optimizes seasonal energy storage, allocation, and reproductive investment through molecular and metabolic crosstalk between the fat body and testis, providing empirical insights into the physiological integration of life-history strategies in animals inhabiting fluctuating environments.

Animals

Demonstration of acid phosphatase activity induced by 20-hydroxyecdysone in the fat body of Calliphora.

In the larval fat body of Calliphora erythrocephala, protein accumulation and autophagic activity occur prior to the onset of puparium formation. The involvement of the lysosomal system in the degradation of sequestered protein and cell organelles can be demonstrated by the electron-microscopical cytochemical localization of the lysosomal marker enzyme acid phosphatase in so-called protein granules. These granules contain not only newly synthetized or absorbed protein but also remnants of cell organelles such as mitochondria and endoplasmic reticulum. Ligation of the larvae behind the brain-ring gland complex prevents the appearance of these acid phosphatase-positive granules. They can be induced in ligated larvae by the injection of 20-hydroxyecdysone into the abdomen. These findings are briefly discussed in relation to the role of moulting hormones in normal development, especially with regard to the induction of autophagic activity.

Acid Phosphatase

Occurrence of an active regulatory mechanism of protein synthesis during starvation and refeeding in Bombyx mori fat body.

The origin of the amino acids which participate in protein synthesis at the recovery from starvation have been determined in the fat body from Bombyx mori larvae. Endogeneous amino acids have been labelled with [3H] leucine and ingested ones with [14C] leucine, allowing their discrimination in the organism. 22 minutes after refeeding, proteosynthetic activity of the fat body, estimated by the polysome level, is increased 2.5 fold. Endogeneous leucine represents more than 90 p. cent of the leucine present in nascent polypeptides. Free leucine pools of the fat body and of hemolymph increase, mainly through the release of endogeneous leucine. It is therefore concluded that refeeding with amino acids induces the production of a signal or critical factor, responsible for the increase in proteosynthetic activity in the fat body.

Adipose Tissue, Brown

Seasonal variations in fat body metabolism of the green frog Rana esculenta (L.).

Rana esculenta (L.), kept under natural conditions, show almost constant body weights in the annual cycle. Fat body weight, however, has a distinct maximum in October decreasing continuously to a May minimum which is also evident in the fat body index. The triglyceride and protein contents show the same course. Suprisingly high amounts of glycogen are found, which reach a maximum in August.

Adipose Tissue

Remodeling of host lipid metabolism by Wolbachia strain wAlbB is associated with lipid accumulation and cardiolipin dysregulation in the Aedes aegypti fat body.

BACKGROUND: The intracellular symbiont Wolbachia, particularly the wAlbB strain, is a promising biocontrol agent against mosquito-borne diseases. Although Wolbachia infection is known to perturb host metabolism, the underlying mechanisms, especially those related to lipid metabolism, remain poorly understood. METHODS: We performed an integrated multi-level analysis of the Aedes aegypti fat body in uninfected and wAlbB-infected mosquitoes, combining histology, biochemistry, untargeted liquid chromatography-mass spectrometry (LC-MS) lipidomics, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways enrichment analysis, reverse transcription quantitative PCR of key metabolic genes, and quantification of acetyl-coenzyme A (acetyl-CoA) and reduced nicotinamide adenine dinucleotide (NADH) levels. RESULTS: wAlbB infection increased fat body wet weight and thickness, accompanied by accumulation of triglyceride and of lipid droplets. Lipidomic analysis further revealed extensive lipidome remodeling, with elevated free fatty acid, diglyceride, and triglyceride, but broad depletion of glycerophospholipids, particularly cardiolipin. These changes were supported by transcriptional alterations: upregulation of fatty acid synthase 1 and glycerol-3-phosphate acyltransferase 1, and downregulation of adipose triglyceride lipase and carnitine palmitoyltransferase 1. Cardiolipin depletion correlated with downregulation of genes involved in its synthesis and remodeling, including phosphatidylglycerophosphate synthase and calcium-independent phospholipase A2γ. These lipid changes were also associated with accumulation of acetyl-CoA and NADH. CONCLUSIONS: Our findings suggest that wAlbB infection is associated with extensive lipid metabolic remodeling in the Aedes aegypti fat body, characterized by accumulation of neutral lipids and cardiolipin depletion, accompanied by transcriptional remodeling of key metabolic enzymes. This study establishes the fat body as a primary tissue-level hub for Wolbachia-associated lipid remodeling and provides a foundational framework for future mechanistic investigations into host-symbiont metabolic interactions.

Animals

Transplantation experiments with the fat body of Calliphora: a morphometric study of induced ultrastructural changes.

Transplantation of fragments of the anterior fat body lobe of 4 day old feeding stage larvae into one day older hosts, which are at the end of feeding, leads to precocious induction of ultrastructural changes in the transplanted cells of the fat body. These changes include alterations in the mean relative and absolute areas of mitochndria, protein granules, lipid droplets and vacuoles. The extent of intracellular changes induced in the transplants depends on the physiological condition of the host. This confirms that alterations in the internal environment at termination of feeding induce prematamorphic changes in cells of the fat body.

Adipose Tissue