Fat Body Protein Research Articles

Studies on carbohydrate, protein and lipid levels in normal and stress conditions in fat body and integument as compared to whole body during development of rice moth, Corcyra cephalonica (St.)

Incorporated in this paper were the results of a study made on the quantitative variation of total carbohydrate, protein and lipid in whole body, fat body and integument of the larval and pupal developmental stages in rice moth, Corcyra cephalonica (St.) a storage grain pest. All three macromolecules referred to in case of whole body, exhibited a progressively decreasing trend from larva to pupa. In fat body total carbohydrate and protein contents were more in pupa than larva, while in integument the said nutrients were less in pupa than larva, showing the reverse results. The lowering down of the nutrients’ level under stress caused by pyrethrum (a botanical insecticide) was also observed. The physiological and statistical significance of these findings was discussed.

A diapause associated protein of the pink bollworm Pectinophora gossypiella Saunders.

A diapause associated protein was electrophoretically isolated from the hemolymph of diapausing last instar larvae of the pink bollworm Pectinophora gossypiella. This protein (M(r) approximately 490,000, glycolipoprotein) was given the name Pectinophora diapause protein (PDP). It is composed of one subunit (M(r) 103,000). The concentration of PDP increased dramatically in the hemolymph of diapausing larvae from 17.4% in prediapause (PD) phase to 29.2% in early diapause (ED) phase reaching a level of 38.6% in larval hemolymph of middiapause (MD) phase. The concentrations of total proteins in the hemolymph of active feeding (A), PD, ED, and MD larvae were 69.8, 106,6, 113.3, and 118 mg/ml, respectively, while those in the fat body of the same larvae were 7.1, 7.4, 8.8, and 4.5 mg/g, respectively. In Pectinophora a drop in the concentration of fat body proteins coincided with a corresponding increase in hemolymph proteins, which suggests an active release of protein from the fat body into the hemolymph during the development of diapause. A partial amino acid sequence of pectinophorin showed the first 15 amino acids starting from the amino terminus of the peptide chain: N-ALA-LYS-THR-ILEU-VAL-GLU-ASN-MET-PRO-PRO-THR-PRO-LEU-ASN-ALA-C.

A novel mechanism of Sarcophaga lectin gene expression

The Sarcophaga lectin gene, an acute-phase-responsive protein of Sarcophaga, was found to be activated when the fat body was incubated in phosphate-buffered insect saline (10 mM NaH2PO4/Na2HPO4, pH 6.2, 2 mM NaHCO3, 1 mM MgCl2, 5 mM KCl, 1 mM CaCl2 and 120 mM NaCl). This activation was selectively suppressed by addition of 2-mercaptoethanol. 2-Mercaptoethanol did not affect the transcription directly, suggesting that the oxidation of the sulfhydryl group of a fat-body protein is required for activation of the Sarcophaga lectin gene. This oxidation reaction seemed to occur immediately when the fat body was incubated in vitro, and once this reaction was initiated, 2-mercaptoethanol no longer inhibited transcription of the Sarcophaga lectin gene. This gene is known to be activated when the larval-body wall of Sarcophaga is injured. It is suggested that the Sarcophaga lectin gene is activated via this novel mechanism on its acute-phase expression in vivo.

Drosophila fat body protein P6 and alcohol dehydrogenase are derived from a common ancestral protein

Drosophila melanogaster alcohol dehydrogenase is an example of convergent evolution: it is not related to the ADHs of other organisms, but to short-chain dehydrogenases, which until now have been found only in bacteria and in mammalian steroid hormone metabolism. We present evidence that the Drosophila ADH is phylogenetically more closely related to P6, another highly expressed protein from the fat body of Drosophila, than it is to the short-chain dehydrogenases. The polypeptide sequence of P6 was inferred from DNA sequence analysis. Both ADH and P6 polypeptides have retained a high structural similarity with respect to the Chou-Fasman prediction of secondary structure and hydropathy. P6 is also homologous to the 25-kd protein from the fat body of Sarcophaga peregrina, whose sequence we have reexamined. The evolution of the P6-ADH family of proteins is characterized by a dramatic increase in the methionine content of P6. Methionine accounts for 20% of P6 amino acids. This is in contrast with the absence of this amino acid in mature ADH. There is evidence that P6 and the 25-kd protein have undergone a parallel and independent enrichment in methionine. When corrected for this, the rate of amino acid replacement shows that the P6-25-kd lineage diverged from insect ADH shortly before the divergence of the ADH gene (Adh) from its 3'-duplication (Adh-dup).

Immunodetection of phosphotyrosine-containing proteins in the integument, fat body and haemocytes of the mediterranean fruit-fly Ceratitis capitata: Possible involvement in pupariation

Antibodies raised against the synthetic hapten p- azobenzyl phosphonate (ABP), which specifically cross react with phosphotyrosine, were used to detect phosphotyrosine-containing proteins in integument, fat body, and haemocytes of C. capitata white pupae. Immunofluorescence experiments demonstrated that fat body, integument, and haemocytes contained proteins phosphorylated in tyrosine residues, while other tissues, such as muscle, showed no fluorescence. To determine which polypeptides are recognized by ABP antibodies, an immunoblotting analysis was performed. The results revealed that the majority of the immunoreactive polypeptide with a M r ranging between 35- and 130 kDa were detected in the integument of C. capitata. Three immunoreactive polypeptides seem to be common in tissues we have examined. 130 kDa is common in integument and fat body, 98 kDa in integument and haemocytes, and 93 kDa is common in haemocytes and fat body. Solubilization of integumental proteins in Tris-HCl buffer pH 7.2 containing either KCl, or NaCl, or urea, or swittergen shows that several phosphotyrosine-containing proteins form non-covalent links with other cuticular components and/or cytoskeleton. Furthermore, treatment of unsolubilized fraction with lysozyme, indicated that some N-acetylglucosamine-containing material prevents extraction with salt solution; this material may be chitin or some intracellular material. The possible contribution of phosphotyrosine containing proteins in the pupariation process is discussed.

Physiological actions by hypertrehalosemic hormone and adipokinetic peptides in adult Blaberus discoidalis cockroaches

Members of the adipokinetic hormone/red pigment-concentrating hormone (AKH/RPCH) family characteristically cause metabolite mobilization by the insect fat body. The present study identified several additional physiological actions in adult Blaberus discoidalis cockroaches that were influenced by synthetic Blaberus hypertrehalosemic hormone (HTH) and other AKH/RPCH family peptides. HTH elevated blood carbohydrate by 4-fold and cytochrome heme a + b synthesis of fat body mitochondria by 3-fold. Both carbohydrate and heme synthesis were dose-responsive to HTH. Carbohydrate synthesis was 10 times more sensitive to HTH than heme synthesis. Heme synthesis was also stimulated by Periplaneta cardioacceleratory hormones (CAH)-I and -II and RPCH but not by AKH-I or -II, at the doses tested. HTH showed strong cardioexcitatory activity. Long-term treatment of decapitated female B. discoidalis with juvenile hormone analog (JHA = methoprene) stimulated by 2.6-fold the rate of synthesis of secreted fat body proteins. HTH enhanced the JHA-dependent export protein synthesis by 42% above that observed with JHA alone. SDS-PAGE demonstrated that JHA determined the nature of the newly synthesized polypeptides; HTH enhanced their synthesis rate. Neither AKH-I nor HTH affected protein synthesis when added directly to isolated fat body. These results demonstrate that peptides of the AKH/RPCH family have multiple physiological actions related to fat body energy metabolism.

Binding of Locust High-Density Lipophorin to Fat Body Proteins. Monitored by an Enzyme-Linked Immunosorbant Assay

Binding of locust high-density lipophorin (HDLp) to fat body proteins coated on immunoassay plates was studied using the ELISA method and ligand blotting techniques. HDLp binding proved to be correlated with the amount of fat body protein coated. From the concentration-dependent total HDLp binding an equilibrium dissociation constant could be calculated (Kd = 1.6 x 10(-8) M). Heparin inhibits the HDLp binding, indicating that positively charged groups are involved in the HDLp-fat body interaction. These groups were shown to be arginyl residues, as the arginine-specific treatment of HDLp by 1,2-cyclohexanedione resulted in a approximately 50% decrease in the binding ability of HDLp. HDLp binding is also affected by the pH. A decrease from pH 7.5 to pH 6.5 increases the binding affinity by approximately 250%. A monoclonal antibody specific for apolipophorin-II (apoLp-II) hampered the HDLp binding significantly, whereas a monoclonal anti-apoLp-I had no effect. Locust fat body HDLp binding proteins are highly specific for locust HDLp.

Effect of Early Protein and Energy Restriction of Large Turkey Toms Fed High-Fat or Low-Fat Realimentation Diets. 2. Carcass Characteristics

Diets were fed to toms from 10 days to 6 wk of age to compare two levels of protein [100% (HP) or 70% (LP) of 1984 National Research Council (NRC) recommendations] in a factorial arrangement with two levels of energy [100% (HE) of 90% (LE) or 1984 NRC reference levels]. Subsequently, the four treatment groups were fed diets containing either 4 or 8% fat, allowing caloric density to increase as the level of fat increased and keeping other nutrients equivalent among the diets. Sample toms were killed at 6, 12, and 20 wk of age to determine carcass composition and organ size. Percentages of dry matter and fat in the carcasses of 6-wk-old toms were increased by LP and decreased by LE (P<.005). There were no protein or energy carry-over effects on body composition at 12 or 20 wk of age. The amount of protein consumed, relative to the amount of protein retained in the carcass, was reduced by LP before and immediately after realimentation (P<.005). From 10 days to 6 wk of age, growth of the skeleton and gut was not affected by dietary protein or energy. Breast muscle development, however, was reduced by LP, and this persisted until 12 wk of age. After 6 wk of age, added dietary fat significantly increased weight gain accompanied by greater body fat and equivalent body protein content levels, irrespective of early nutrition.

The growth to maturity of lean and fat lines of broiler chickens given diets of different protein content: body composition, plasma lipoprotein concentration and initial egg production

ABSTRACTThe proportions of abdominal fat and total body lipid and protein were measured up to 30 weeks in males and 21 weeks in females from lines of lean and fat broiler chickens given diets of different protein content. There was a constant relationship between the proportions of abdominal fat and body lipid independent of line, diet or age. Data on males showed effects of line and diet on body fatness at all ages up to 30 weeks. In females, line and diet had effects on body fatness during early growth but little effect on composition at 21 weeks. Plasma very low density lipoprotein concentration was higher in the fat line in both sexes at all ages. Egg production over the first few weeks of the laying period was much higher in lean line hens.

The role of adipokinetic hormone in the control of vitellogenesis in locusts

Vitellogenesis in locusts is synchronized with the cyclic maturation of oocytes. Vitellogenesis by excised fat body of gravid females is differentially inhibited 80–90% when locust adipokinetic hormone I (AKH-I) is added to the incubation media. Hemolymph methanolic extracts completely inhibit fat body protein synthesis in vitro when the donor females are at the end of the ovarian cycle (6 mm stage), but not when taken from earlier stages. Hemolymph methanolic extracts from vitellogenic females at the 6 mm stage are separated by HPLC into three distinct inhibitors of protein synthesis, one of which is AKH-I. AKH-RIA of hemolymph during the first ovarian cycle reveals no AKH-I during active vitellogenesis, but a marked increase to about 5 ng per female at the end of egg maturation. A development of responsiveness to AKH-I is evident in female fat body as vitellogenesis proceeds. AKH-I is involved in the negative control of vitellogenesis.

Purification, properties, and titer of a hemolymph trophic factor in larvae and pupae of Manduca sexta

Purification of a hemolymph protein (hemolymph trophic factor, or HTF) from last instar larvae of Manduca sexta was achieved using Sephadex G15-120 gel filtration and DEAE anion exchange chromatography. Homogeneity was visualized using SDS gel electrophoresis and ampholytic chromatofocusing. HTF was estimated to be a tetrameric protein with a molecular weight of 286 K and a Stokes' radius of 55.3 × 10 −8 cm by agarose bead gel filtration; chromatofocusing suggests an isoionic point > 10. Polyclonal antibodies to HTF were prepared in rabbits and an ELISA was developed. The ELISA was used to titer HTF during the last larval instar and day 1 and 14 of the pupal stage and estimates a maximum of 1.5 mg/ml larval hemolymph on day 6 with a smaller larval peak of 0.75 mg/ml at day 3 and titers of 0.70 and 0.35 mg/ml on the 2 pupal days, respectively. ELISA of aqueous extracts of larval fat body, epidermis, and cuticle demonstrate that HTF comprises nearly a third of the soluble fat body protein and is a lesser component of epidermis and cuticle. The physiological role of HTF has not yet been determined.

Location of Drosophila C virus target organs in Drosophila host population by an immunofluorescence technique

Using the immunofluorescence technique we attempted to locate, in the Drosophila host, Drosophila C virus (DCV) target organs after injection of adult flies. Two kinds of organs were infected: those which play a role in reproductive function, including the fat body and follicular cells, and others, including thoracic muscle fibers, tracheal cells, and the digestive tract. These organs correspond to those found in previous tests. Fat body proteins of a DCV-free host population seemed to cross-react with antivirus C antibody. This immune response depended on the origin of the host population. It is known that, when DCV is ingested from the first larval instar, it may have beneficial effects upon host development and reproduction. As DCV has a narrow host spectrum, it is suggested that it is well adapted to its natural host. Hypotheses are proposed to explain how the host resists viral infection and may in fact benefit from such an infection.

Aging and reproduction fail to increase body fat in S 5B/P1 rats

Nine young female S 5B/P1 rats, 340 days of age, and 9 old female S 5B/P1 rats, 840 days of age, were evaluated for food intake, body composition, 3 fat depot weights and organ weights. Old and young rats had the same percentage of body fat and protein. Inguinal, parametrial and perirenal-retroperitoneal fat depot weights were similar. Hearts and kidneys were heavier in old than in young rats. Coefficients of variability were greater for body weight, body fat, fat depot weights and body protein in old than in young rats. Approximately one-year-old rats which delivered two litters had only 10% carcass fat whereas female rats which were never bred had 14% body fat.

In vivo and in vitro effects of epofenonane on juvenile hormone esterase activity in tissues of last stadium larvae of Trichoplusia ni

Topical application of the juvenoid, epofenonane, to last stadium postwandering larvae of Trichoplusia ni caused a precocious elevation of juvenile hormone esterase (JHE) activity that was tissue speific and time dependent. This increase in enzyme activity over controls was most dramatic in the hemolymph, whereas increases in the fat body were lower. Antibodies raised against JHE reacted on Western blots with a fat body and hemolymph protein present in epofenonane treated and untreated last stadium day 3 larvae. The abundance of this protein, which comigrated with JHE, closely coincided with the temporal increases in JHE catalytic activity that occurred in response to treatment in vivo with epofenonane. The presence of epofenonane (5–10,000 nM) in the medium at the start of fat body incubations failed to shift the temporal appearance of JHE activity or boost activity levels significantly over those of controls. If larvae were treated in vivo with epofenonane before fat body tissue was removed, only a small, but significant increase in JHE activity was found in vitro. The rate of enzyme secretion was insufficient to account for the rapid increases in enzyme activity that occur in the hemolymph in response to epofenonane, even though tissue held in vitro was deemed viable by monitoring lactate dehydrogenase activity in the medium, fat body intracellular ATP, and the incorporation of [ 35S]methionine into fat body protein. Fat body tissue removed from various aged last stadium larvae released enzyme at different rates in vitro.

Properties, synthesis, and accumulation of storage proteins in Pieris rapae L.

AbstractTwo kinds of storage proteins (SP‐1, SP‐2) were confirmed in hemolymph and fat body of Pieris rapae during metamorphosis. Both proteins were present in high concentrations in the hemolymph during the last larval instar. Hemolymph concentrations of SP‐1 and SP‐2 dropped after pupation as the proteins were being deposited in fat bodies. SP‐2 is present in a larger amount than SP‐1. Detailed studies on storage proteins determined their properties, mode of synthesis, and accumulation in the fat body.SP‐1 has a molecular weight of 500,000 and consists of one type of subunit (Mr 77,000), while SP‐2 has a molecular weight of 460,000 and is composed of two types of subunits (Mr 80,000 and 69,000). The pl values of SP‐1 and SP‐2 were determined to be 6.97 and 7.06, respectively.Fat body cells from 1‐day‐old fifth instar larvae synthesized storage proteins in large amounts, whereas those from late prepupae exhibited high protein sequestration. Proteins taken up in fat body accumulated in dense granules during the pupal stage but sharply decreased at the adult stage.Morphological changes in the fat body tissues were observed during the larval‐pupal transformation; the nuclei of fat body cells became irregularly shaped, and the boundaries between cells seemed to be obscure. Synthesis, storage, or degradation of storage proteins in fat body during development is closely associated with morphological changes in the tissues.

Binding of lipophorin to the fat body of the migratory locust

The interaction of locust high density lipophorin (HDLp) with pieces of fat body tissue was studied at 33°C using a radiolabelled ligand binding assay. Under the assay conditions, binding of tritium-labelled HDLp ([ 3H]HDLp) was demonstrated to correlate linearly with tissue concentration up to ∼ 7 mg of fat body protein per ml of incubation medium. The [ 3H]HDLp binding that was displaceable by a 20-fold excess of unlabelled HDLp (which is an approximation of the specific binding) reached equilibrium after ∼ 2 h, whereas low levels of non-displaceable binding increased linearly during this time interval. Analysis of the concentration dependent total binding of [ 3H]HDLp revealed the presence of a specific binding site with an equilibrium dissociation constant of K d = 3.1 (±0.5) × 10 −7 M and a maximal binding capacity of 9.8 (±0.5) ng μg −1 tissue protein. Competition experiments demonstrated that the affinity of unlabelled HDLp for the binding site is similar to the affinity of [ 3H]HDLp. Unlabelled low density lipophorin (LDLp), however, was shown to have an approx. 20-fold lower affinity for the binding site.

Neuroendocrine and juvenile hormone effects on fat body protein synthesis during the reproductive cycle in female Blaberus discoidalis cockroaches

Ovarian protein content and fat body protein synthesis were measured during the first gonotrophic cycle in virgin female Blaberus discoidalis cockroaches. Protein systhesis was measured for in vitro fat bodies from animals treated with combinations of a juvenile hor mone analog (JHA = methoprene) and corpora cardiaca (CC) extracts. Ovarian protein content began to increase on Day 5 of adult life and reached its maximum at Days 20–22. Synthesis of proteins secreted by the in vitro fat body increased by 12-fold between emergence and its maximum on Day 18, then declined to nearly its original level by Day 33. Synthesis of nonsecreted, fat body proteins increased by 4-fold between emergence and a maximum on Day 21, then declined. CC extracts and JHA were administered to decapitated females to determine their regulative effects on fat body protein synthesis. The synthesis by the fat body of nonsecreted proteins was increased by both JHA and CC extracts. In contrast, synthesis of secreted proteins increased only in the presence of JHA. CC extracts, alone, had no effects on the synthesis of secreted proteins, but administration of CC extracts in combination with JHA increased the synthesis of the secreted proteins by 55% above that observed with JHA alone. SDS-PAGE of proteins secreted into the medium by the in vitro fat body demonstrated that JHA stimulated the synthesis of specific polypeptides, whereas CC extracts did not affect the synthesis of specific-secreted polypeptides. These results suggest that JH regulates specific protein synthesis by the fat body of B. discoidalis; neurohormones elevate the general capacity of the fat body for protein synthesis and amplify the specific effects of JH.

Detection of protein similarities using nucleotide sequence databases.

A simple procedure is described for finding similarities between proteins using nucleotide sequence databases. The approach is illustrated by several examples of previously unknown correspondences with important biological implications: Drosophila elongation factor Tu is shown to be encoded by two genes that are differently expressed during development; a cluster of three Drosophila genes likely encode maltases; a flesh-fly fat body protein resembles the hypothesized Drosophila alcohol dehydrogenase ancestral protein; an unknown protein encoded at the multifunctional E. coli hisT locus resembles aspartate beta-semialdehyde dehydrogenase; and the E. coli tyrR protein is related to nitrogen regulatory proteins. These and other matches were discovered using a personal computer of the type available in most laboratories collecting DNA sequence data. As relatively few sequences were sampled to find these matches, it is likely that much of the existing data has not been adequately examined.

ニジュウヤホシテントウ成虫の蛋白質の電気泳動による分離と泳動パターンの前休眠期における変化

ニジュウヤホシテントウ成虫の体液,脂肪体の蛋白質をポリアクリルアミド・ゲル電気泳動によって分離し,それぞれの蛋白質成分の前休眠期および脂肪体発達に伴う変化を観察した。この昆虫では,雌特異的なvitellogenin様蛋白質は認められたが,それらは卵巣蛋白質の主要成分ではなかった。休眠に特異的な蛋白質は認められなかったが,ほとんどの体液,および,脂肪体蛋白質成分は前休眠期の進行につれて増加した。体液蛋白質の中に脂肪体が発達すると消失するものも認められ,一成分は光周期感受性消失後に消失した。体液中には色素蛋白質と呼ぶべきものが存在した。これらは羽化時には色素と結合しておらず,摂食が始まると色素と結合して電気泳動上の相対距離が小さいほうへ変化することが明らかになった。

20-Hydroxyecdysone induced phosphorylation of fat body proteins in Mamestra brassicae

20-Hydroxyecdysine-induced phosphorylation of certin fat body proteins, has been observed in Mamestra brassicae during the wandering period of the last larval stage. After fractionation of fat body cells one of the phosphorylated proteins was localized in the fractions containing mainly protein storage granules. In the same period the activity of acid phosphatase was very low in the presence of 20-hydroxyecdysone, especially in the granule fractions. The functional relation of protein phosphorylation and the inhibition of the lysosomal enzyme activity is suggested.