Trehalose and trehalose-hydrolyzing enzyme in the haemolymph of Locusta migratoria infected with Metarhizium anisopliae strain CQMa102

Topical application of the Metarhizium anisopliae var. acridum specialist strain CQMa 102 to the locust Locusta migratoria manilensis results in changes of the concentrations of trehalose and glucose in the haemolymph. Micrographs of the locust haemolymph shows Metarhizium anisopliae can effectivly penetrate the external skeleton of locust and after 2 days infection, the hyphae body will appear in the haemolymph of infected insects. The time in decrease of trehalose concentration coincided with that in increase of trehalose-hydrolysing enzyme activity in the haemolymph of the fungus-infected insects. Overlay gel analysis indicated there was considerably more trehalose-hydrolysing activity in the haemolymph of locusts infected by fungus than in controls. A comparable isoform was identified in in vitro culture of the fungus, suggesting a fungal origin for the in vivo enzyme. Haemolymph trehalose decreased significantly during mycosis of locusts by M. anisopliae. All these results suggested that this fungus may take advantage of competing nutrient utilization against the insect by its trehalose-hydrolyzing enzyme secretion. It may provide fundamental knowledge for fungal pathogenesis.     

Trehalose-hydrolysing enzymes of Metarhizium anisopliae and their role in pathogenesis of the tobacco hornworm,Manduca sexta

Trehalose is the main haemolymph sugar in most insects including the tobacco hornworm, Manduca sexta, and is potentially a prime target for an invading pathogenic fungus. There was considerably more trehalose-hydrolysing activity in the haemolymph of caterpillars infected with Metarhizium anisopliae than in controls. This appeared to be due primarily to additional isoforms; one of which could also hydrolyse maltose and was designated an alpha-glucosidase. A comparable isoform was identified in in vitro culture of the fungus, supporting a fungal origin for the in vivo enzyme. The in vitro fungal enzyme, alpha-glucosidase-1 (alpha-gluc-1), was purified to homogeneity and partially characterised. A study with the trehalase inhibitor trehazolin and C14 trehalose suggested that extracellular hydrolysis is important for fungal mobilisation of trehalose. Haemolymph glucose increases significantly during mycosis of tobacco hornworm larvae by M. anisopliae, consistent with the hydrolysis of trehalose by extracellular fungal enzymes. The implications for the host insect are discussed.     

Trehalose turnover and the coexistence of trehalose and active trehalase in cockroach haemolymph

In the cockroaches Periplaneta americana, Periplaneta australasiae, Leucophaea maderae, and Nauphoeta cinerea, undiluted haemolymph, undiluted haemolymph to which 10% solid trehalose was added, and haemolymph diluted 100 or more times with 1% trehalose solution showed approximately equal trehalase activities (3 to 8 mg/ml per hr). No evidence for the presence of a trehalase inhibitor was found.Freshly drawn haemolymph of Periplaneta americana contained 14 to 16 mg trehalose/ml, which on standing was hydrolyzed to glucose at a rate of 4 to 8 mg/ml per hr. In this cockroach, the rate of haemolymph trehalose turnover was only 1.3 mg/ml per hr. This means that in vitro trehalose is hydrolyzed by undiluted haemolymph at several times the rate at which it is replaced in the haemolymph of the intact insect. The mechanism through which trehalose and trehalase can coexist in the haemolymph of the intact cockroach remains therefore unexplained.     

Reduction of glycogen in eggs of the silkworm,Bombyx mori,by use of a trehalase inhibitor,trehazolin, and diapause induction in glycogen-reduced eggs

A new trehalase inhibitor, trehazolin, caused a potent inhibition of ovary trehalase in the silkworm, Bombyx mori. A single injection of trehazolin into pupae (40&mgr;g/animal) did not interfere with the accumulation of proteins and lipids, but markedly reduced glycogen content in eggs accompanied by a remarkable increase in hemolymph trehalose levels. The most potent effect of trehazolin was expressed in eggs that developed at the mid-stage of pupal-adult development. In these eggs glycogen content was reduced to a trace level, less than 3% of that of the control. The reduced glycogen content was almost restored to the control level by injection of glucose but not by trehalose. Trehazolin treatment influenced oviposition and larval hatching, whereas embryogenesis went on normally in glycogen-reduced eggs. Injection of synthetic diapause hormone into non-diapause type hosts induced an incidence of 45% diapause in the eggs and increased their glycogen content. Surprisingly, injection of trehazolin never affected diapause induction by the hormone, despite considerably reduced glycogen content in these eggs. Thus, our findings provide a new method for production of eggs containing various amounts of glycogen, and a novel system for analyzing diapause-associated metabolism besides the well-known glycogen-sorbitol metabolism.     

家蚕感染蛹虫草后的生理生化变化

蛹虫草分生孢子侵染5龄家蚕Bombyx mori后,家蚕血淋巴中总糖、海藻糖、蛋白质和甘油酯含量均有不同程度的下降,其中甘油酯含量下降最为明显。海藻糖酶活性在侵染初期也明显降低。接种后家蚕体内的保护酶超氧化物歧化酶、过氧化物酶和过氧化氢酶活性也有较大变化,其中超氧化物歧化酶活性上升最为明显,在4日内由441.841 U/mL升至601.255 U/mL。     

高温对家蚕三品系血淋巴中糖水平的影响（英文）

家蚕Bombyx mori的两个二化性品系热耐受型NB4D2和热敏感型CSR2均适合于温带气候,而多化性的PM（Pure Mysore) 品系适合于热带气候,将这3种品系5龄幼虫分别置于32℃和36℃的高温下,观察高温对其5龄幼虫至蛹期血淋巴中糖含量及海藻糖酶活性的影响。结果表明： PM幼虫和蛹的死亡率均小于NB4D2和CSR2。在蜕皮期间血淋巴海藻糖水平较高,而葡萄糖水平及海藻糖酶活性较低。32℃和36℃的高温下,幼虫蜕皮期间血淋巴中糖含量及海藻糖酶活性仅在其各自的水平上表现为小幅度的增加。蜕皮后幼虫血淋巴中海藻糖含量显著下降,而葡萄糖含量和海藻糖酶活性显著上升。在较高温度下,蜕皮后幼虫血淋巴中海藻糖含量下降幅度更大,而葡萄糖含量及海藻糖酶活性上升水平也更加显著。25±1℃下取食幼虫血淋巴中葡萄糖含量显著下降,海藻糖含量显著上升;3℃和36℃下PM 和NB4D2取食幼虫血淋巴葡萄糖和海藻糖含量以及海藻糖酶活性增加,而CSR2均减少或降低。吐丝幼虫血淋巴中葡萄糖含量及海藻糖酶活性显著下降,海藻糖小幅度下降。而在较高温度下,耐热型PM 和NB4D2吐丝家蚕血淋巴糖含量含量和海藻糖酶活性明显增加,而热敏感型CSR2的则明显下降。这3种品系蛹发育期的血淋巴糖含量及海藻糖酶活性均下降。在两较高温度下,PM蛹期血淋巴糖和海藻糖酶活性增加,而NB4D2 36℃时增加幅度小于32℃时。对于CSR2,32℃时观察到其血淋巴葡萄糖含量增加,但当环境温度增加到36℃时其血淋巴葡萄糖含量降至正常水平下。然而,当CSR2的蛹置于32℃和36℃时血淋巴海藻糖含量及其酶活性下降,且36℃时下降幅度更大。因此,桑蚕对高温的适应取决于家蚕的品系及发育阶段,并可通过其血淋巴糖及海藻糖酶活性水平进行验证。     

Identification of an extracellular acid trehalase and its gene involved in fungal pathogenesis of Metarizium anisopliae

Trehalose is the main sugar in the haemolymph of insects and is a key nutrient source for an insect pathogenic fungus. Secretion of trehalose-hydrolysing enzymes may be a prerequisite for successful exploitation of this resource by the pathogen. An acid trehalase [EC 3.2.1.28] was purified to homogeneity from a culture of a locust-specific pathogen, Metarhizium anisopliae, and its properties were characterized. The gene (ATM1) of this acid trehalase was also isolated. The pure enzyme can efficiently hydrolyze haemolymph trehalose into glucose in vitro. The new acid trehalase appearing in the haemolymph of Locusta migratoria infected with M. anisopliae had the same pI and substrate specificity as the purified fungal acid trehalase, and the concentration of trehalose in the haemolymph decreased sharply after infection. RT-PCR also revealed the ATM1 gene's expression in the haemolymph of the infected insects. Our results indicated that the acid trehalase may serve as an "energy scavenger" and deplete blood trehalose during fungal pathogenesis.     

α-Glucosidase activity in haemolymph of the American cockroach, Periplaneta americana

α-Glucosidase activity of whole haemolymph has been investigated in adult males of the American cockroach, Periplaneta americana. Two electrophoretically distinguishable enzymes capable of hydrolysing α-glucosidic linkages are present in the serum component of the haemolymph, and one of these hydrolyses trehalose. Trehalase activity is also present in haemocytes, and the haemocyte enzyme shares an identical electrophoretic mobility and similar pH sensitivity with the serum trehalase. Furthermore, both enzymes are inhibited to the same extent by sodium ethylene diamine tetracetate (EDTA); thus it is suggested that the same enzyme may be responsible for trehalase activity in the two components. The K_m of EDTA-inhibited trehalase is 3·3 mM and this value is reduced to 1·8 mM upon activation of the enzyme by calcium ions. The properties of the trehalase are discussed in light of the possible rôle of the enzyme in regulating haemolymph trehalose and glucose concentrations.     

Cellular localization and proposed function of midgut trehalase in the silkworm larva, Bombyx mori

A sorbitol density gradient analysis with the aid of several marker enzymes demonstrated that midgut trehalase of the silkworm larvae. Bombyx mori, was localized in the microsomal membranes, but not in mitochondria, lysosomes and microvilli at the apical surface. Electron microscopic examination showed that trehalase-enriched membrane fraction consisted of heterogeneous mixtures of membrane vesicles derived from the endoplasmic reticulum and plasma membrane parts other than the microvillus membrane. The enzyme-histochemical stains of trehalase activity on the midgut section could be detected only at the basal surface of the epithelium against haemocoel. Such a specific localization was further confirmed by immunohistochemistry with the peroxidase-conjugated antibody technique. Thus, it is concluded that midgut trehalase of silkworm larvae is situated on the plasma membrane at the basal surface of the epithelium. An intact preparation of midgut incubated in vitro in the medium containing [(14)C]trehalose could hydrolyse trehalose into glucose and take it up into the cell, although some glucose was liberated into the medium when incubated for extended periods. These results suggest that midgut trehalase plays a physiological role in utilization of haemolymph trehalose not in nutrient absorption.     

Three enzymes for trehalose synthesis in Bradyrhizobium cultured bacteria and in bacteroids from soybean nodules

alpha,alpha-Trehalose is a disaccharide accumulated by many microorganisms, including rhizobia, and a common role for trehalose is protection of membrane and protein structure during periods of stress, such as desiccation. Cultured Bradyrhizobium japonicum and B. elkanii were found to have three enzymes for trehalose synthesis: trehalose synthase (TS), maltooligosyltrehalose synthase (MOTS), and trehalose-6-phosphate synthetase. The activity level of the latter enzyme was much higher than those of the other two in cultured bacteria, but the reverse was true in bacteroids from nodules. Although TS was the dominant enzyme in bacteroids, the source of maltose, the substrate for TS, is not clear; i.e., the maltose concentration in nodules was very low and no maltose was formed by bacteroid protein preparations from maltooligosaccharides. Because bacteroid protein preparations contained high trehalase activity, it was imperative to inhibit this enzyme in studies of TS and MOTS in bacteroids. Validamycin A, a commonly used trehalase inhibitor, was found to also inhibit TS and MOTS, and other trehalase inhibitors, such as trehazolin, must be used in studies of these enzymes in nodules. The results of a survey of five other species of rhizobia indicated that most species sampled had only one major mechanism for trehalose synthesis. The presence of three totally independent mechanisms for the synthesis of trehalose by Bradyrhizobium species suggests that this disaccharide is important in the function of this organism both in the free-living state and in symbiosis.     

Three Enzymes for Trehalose Synthesis in Bradyrhizobium Cultured Bacteria and in Bacteroids from Soybean Nodules

α,α-Trehalose is a disaccharide accumulated by many microorganisms, including rhizobia, and a common role for trehalose is protection of membrane and protein structure during periods of stress, such as desiccation. Cultured Bradyrhizobium japonicum and B. elkanii were found to have three enzymes for trehalose synthesis: trehalose synthase (TS), maltooligosyltrehalose synthase (MOTS), and trehalose-6-phosphate synthetase. The activity level of the latter enzyme was much higher than those of the other two in cultured bacteria, but the reverse was true in bacteroids from nodules. Although TS was the dominant enzyme in bacteroids, the source of maltose, the substrate for TS, is not clear; i.e., the maltose concentration in nodules was very low and no maltose was formed by bacteroid protein preparations from maltooligosaccharides. Because bacteroid protein preparations contained high trehalase activity, it was imperative to inhibit this enzyme in studies of TS and MOTS in bacteroids. Validamycin A, a commonly used trehalase inhibitor, was found to also inhibit TS and MOTS, and other trehalase inhibitors, such as trehazolin, must be used in studies of these enzymes in nodules. The results of a survey of five other species of rhizobia indicated that most species sampled had only one major mechanism for trehalose synthesis. The presence of three totally independent mechanisms for the synthesis of trehalose by Bradyrhizobium species suggests that this disaccharide is important in the function of this organism both in the free-living state and in symbiosis.     

The physiological role of the peritrophic membrane and trehalase: Digestive enzymes in the midgut and excreta of starved larvae of Rhynchosciara

Amylase, cellulase, trehalase, aminopeptidase and trypsin were determined using the midgut and trehalose using the haemolymph of starved and of subsequently fed larvae of Rhynchosciara americana. Midgut trehalase activity decreases steadily during starvation and increases again on feeding, whereas haemolymph trehalose titres remain constant, suggesting that trehalase is a true digestive enzyme. The decrease in amylase, cellulase and trypsin activity in the midgut during starvation is of the same order as that recovered from the excreta. Since this finding is exactly what one would expect if enzyme production stops in response to starvation, this supports the hypothesis that synthesis that synthesis of these enzymes is controlled. The excretion rate of amylase, cellulase and trypsin is very low in comparison to their activity inside the peritrophic membrane and the travel time of the food bolus through the gut. It is proposed that the peritrophic membrane separates two extracellular sites for digestion as an adaptation to conserve secreted enzymes. This could be accomplished by the existence of an endo-ectoperitrophic circulation of the enzymes involved in the initial attack on the food and by restricting to the ectoperitrophic fluid the enzymes which participate only in intermediary digestion of food.     

沉默类胰岛素多肽(Ilp)基因对褐飞虱翅和卵巢发育及海藻糖代谢的影响

【目的】类胰岛素多肽(insulin-like peptide, Ilp)位于胰岛素信号通路最上游,其在糖类物质调控中发挥关键作用。本研究则旨在探究Ilp在褐飞虱Nilaparvata lugens海藻糖代谢平衡的调控作用。【方法】以褐飞虱5龄若虫为实验材料,采用RNAi技术干扰Ilps的表达,观察RNAi后褐飞虱的表型以及雌成虫的卵巢发育。RNAi 48 h与72 h后,采用生化方法测定褐飞虱5龄若虫体内海藻糖、糖原和葡萄糖含量以及海藻糖酶活性变化;采用qPCR检测海藻糖酶基因(TRE1-1, TRE1-2和TRE2)和海藻糖合成酶基因(TPS1和TPS2)的表达量变化。【结果】dsRNA可有效抑制Ilps的表达,导致褐飞虱出现异常翅型,且注射dsIlp3以及dsIlp1+dsIlp2+dsIlp3+dsIlp4发现褐飞虱2日龄雌成虫卵巢发育不完全。分别注射dsIlp1-4和dsIlp1+dsIlp2+dsIlp3+dsIlp4后48 h均能显著提高葡萄糖含量;分别注射dsIlp2, dsIlp3及dsIlp4后48 h显著提高了糖原含量;分别注射dsIlp3和dsIlp4后48 h能够显著提高海藻糖含量,而分别抑制Ilp2和Ilp4 72 h后海藻糖含量显著下降,但注射dsIlp1+dsIlp2+dsIlp3+dsIlp4后48和72 h海藻糖含量都显著上升。注射dsIlp1+dsIlp2+dsIlp3+dsIlp4后72 h可溶性海藻糖酶活性均显著上升,膜结合型海藻糖酶活性则在分别注射dsIlp3, dsIlp4和dsIlp1+dsIlp2+dsIlp3+dsIlp4后72 h显著下降;分别注射dsIlp1, dsIlp2和dsIlp4后TRE1-1, TRE1-2, TRE2, TPS1和TPS2的表达量显著下降。【结论】沉默Ilp基因对褐飞虱的发育以及繁殖有一定的阻碍作用,且能够提高褐飞虱体内葡萄糖与糖原的含量,下调海藻糖酶与海藻糖合成酶基因表达量,提高可溶性海藻糖酶的活性,进而调控海藻糖的代谢。     

Interrelationships between haemolymph lipid and carbohydrate during starvation in Locusta

During starvation in adult female Locusta, the haemolymph total lipid concentration increases markedly while that of the total carbohydrate decreases. The majority of the increased haemolymph lipid is diglyceride and 75% of this is associated with a high molecular weight lipoprotein (A⁺) which disappears rapidly after feeding when the total lipid concentration is restored to the normal resting value. The effect of feeding can be mimicked by injecting or feeding starved locusts with sugars but not with protein. The lowering of the haemolymph total diglyceride concentration in starved locusts by injection of carbohydrates is dose-related and, at doses in excess of 4 mg per locust, almost normal values (for fed locusts) are obtained within 6 hr. It is suggested that in the haemolymph there is an inverse relationship between the concentration of diglyceride and that of trehalose.     

Trehalose synthesis and metabolism are required at different stages of plant infection by Magnaporthe grisea

The relationship of trehalose metabolism to fungal virulence was explored in the rice blast fungus Magnaporthe grisea. To determine the role of trehalose synthesis in pathogenesis, we identified and deleted TPS1, encoding trehalose-6-phosphate synthase. A Deltatps1 mutant failed to synthesize trehalose, sporulated poorly and was greatly attenuated in pathogenicity. Appressoria produced by Deltatps1 did not develop full turgor or elaborate penetration hyphae efficiently. To determine the role of subsequent trehalose breakdown, we deleted NTH1, which encodes a neutral trehalase. Nth1 mutants infected plants normally, but showed attenuated pathogenicity due to a decreased ability to colonize plant tissue. A second trehalase was also identified, required both for growth on trehalose and mobilization of intracellular trehalose during infection-related development. TRE1 encodes a cell wall-localized enzyme with characteristics of both neutral and acidic trehalases, but is dispensable for pathogenicity. Our results indicate that trehalose synthesis, but not its subsequent breakdown, is required for primary plant infection by M.grisea, while trehalose degradation is important for efficient development of the fungus in plant tissue following initial infection.     

海藻糖酶基因TRE2-like和TRE2在异色瓢虫羽化过程中的表达与功能

【目的】异色瓢虫Harmonia axyridis是一种重要的捕食性天敌昆虫,海藻糖在异色瓢虫的变态发育、羽化等整个生命过程都起着重要的作用。本研究以前期获得的类似膜结合型海藻糖酶(TRE2-like)与膜结合型海藻糖酶(TRE2)基因为基础,探讨在异色瓢虫羽化阶段这两个海藻糖酶的潜在功能,为阐明异色瓢虫从蛹发育到成虫时海藻糖代谢机制提供参考。【方法】根据TRE2-like和TRE2基因序列设计双链RNA(dsRNA)区域片段并合成对应的dsRNA,通过RNAi将其注射到异色瓢虫2日龄蛹中。采用实时荧光定量PCR(RT-qPCR)检测RNAi处理后羽化第1天的异色瓢虫成虫糖代谢相关基因的表达;同时采用蒽酮比色法、酶标法等分别测定RNAi处理后羽化第1天的异色瓢虫成虫主要糖类物质含量及TRE活性变化,并观察异色瓢虫羽化后的表型变化。【结果】结果表明,与对照组(dsGFP注射组)相比,异色瓢虫2日龄蛹被注射TRE2-like或TRE2 dsRNA后,其新羽化成虫体内TRE2-like和TRE2表达量均极显著下调,且少数个体出现了蜕皮与翅形成困难等畸形表型。可溶性海藻糖酶活性在注射dsTRE2-like后显著降低,膜结合型海藻糖酶活性在注射dsTRE2后显著降低;注射dsTRE2后糖原含量显著下降,注射dsTRE2-like后糖原和海藻糖含量显著下降,注射dsTRE2-like+dsTRE2后糖原和葡萄糖含量显著下降,且海藻糖含量极显著下降。注射dsTRE2-like, dsTRE2和dsTRE2-like+dsTRE2后可溶性海藻糖酶基因TRE1-1和TRE1-2表达下降或显著下降,而TRE1-5表达上升或显著上升,海藻糖合成酶(trealose-6-phosphate synthase, TPS)、糖原磷酸化酶(glycogen phosphorylase, GP)、糖原合成酶(glycogen synthase, GS)基因的表达均显著下调。【结论】TRE2-like和TRE2基因表达被抑制后,异色瓢虫海藻糖等代谢受到影响。研究结果为探究异色瓢虫体内膜结合型海藻糖酶的潜在功能和调控机制奠定了基础。     

Changes in lipophorins are related to the activation of phenoloxidase in the haemolymph of Locusta migratoria in response to injection of immunogens

In Locusta migratoria, activation of phenoloxidase in the haemolymph in response to injection of laminarin is age-dependent: being absent in fifth instar nymphs and newly emerged adults, and only becoming evident four days after the final moult. This pattern of change in phenoloxidase activation correlates with the pattern of change in the concentration of apolipophorin-III (apoLp-III) in the haemolymph. Injection of a conspecific adipokinetic hormone (Lom-AKH-I) has no effect on the phenoloxidase response in nymphs or newly emerged adults but, in adults older than four days, co-injection of the hormone with laminarin prolongs the activation of phenoloxidase in the haemolymph: a similar enhancement of the response to laminarin is observed in locusts that have been starved for 48 h but not injected with AKH-I. During most of the fifth stadium, injection of laminarin results in a decrease in the level of prophenoloxidase in the haemolymph; an effect that is not observed in adults of any age. Marked changes in the concentration of apoLp-III, and the formation of LDLp in the haemolymph, are observed after injection of laminarin (or LPS) and these are remarkably similar, at least qualitatively, to those that occur after injection of AKH-I. The involvement of lipophorins in the activation of locust prophenoloxidase in response to immunogens is discussed.     

Trehalase of Escherichia coli. Mapping and cloning of its structural gene and identification of the enzyme as a periplasmic protein induced under high osmolarity growth conditions

Escherichia coli can use the nonreducing disaccharide trehalose as a sole source of carbon and energy. Trehalose transport into the cell is mediated via the phosphotransferase system, and a mutant depleted in the nonspecific proteins enzyme I, HPr, and enzyme IIIGlc of this system was not only unable to grow on glucose or mannitol but also was strongly reduced in its ability to grow on trehalose. A pseudorevertant (PPA69) of such a deletion mutant was isolated that could again grow on glucose but not on mannitol. This revertant could now also use trehalose as a carbon source due to a constitutive galactose permease. PPA69 was subjected to Tn10 insertional mutagenesis, and a mutant (UE5) was isolated that no longer could use trehalose as a carbon source but could still grow on glucose. UE5 lacked a periplasmic trehalase that was present in PPA69. P1-mediated transduction of this Tn10 insertion (treA::Tn10) into a pts+ wild-type strain (MC4100) had no effect on the ability of MC4100 to grow on trehalose but resulted in loss of the periplasmic trehalase activity. The Tn10 insertion was mapped at 26 min on the E. coli linkage map and was 3% cotransducible with trp, in the order treA::Tn10, trp, cys. Trehalase activity in MC4100 was not induced by growth in the presence of trehalose but increased by about 10-fold when 0.6 M sucrose was added to minimal growth medium. Using the in vivo mini-Mu cloning system and growth on trehalose as selection, we cloned the treA gene. A 9-kilobase EcoRI fragment containing treA was subcloned into pBR322. Strains carrying this plasmid (pTRE5) contained about 100-fold higher periplasmic trehalase activity than PPA69 or MC4100. Using polyacrylamide gel electrophoresis, we found a protein of molecular weight 58,000 among the periplasmic proteins of the pTRE5-carrying strain that was absent in UE5. This protein was purified by ammonium sulfate precipitation and DEAE-Sepharose ion-exchange chromatography and contained all the trehalase activity. Minicells containing the treA+ plasmid produced, in addition to three other proteins, the 58,000-dalton protein. Thus, the plasmid carries the structural gene for the periplasmic trehalase and not just a gene involved in the regulation of the enzyme.     

Hormonal regulation of trehalose metabolism in the blowfly, Phormia regina: interaction between hypertrehalosemic and hypotrehalosemic hormones

Hypertrehalosemia occurs two days after cardiacectomy of adult male Phormia regina with no attendant change in fat body glycogen. In spite of this, cardiacectomized flies caused to fly for 10 min show a lower rate of haemolymph trehalose turnover, and seem to have a decreased capability for synthesizing trehalose from haemolymph glucose. Phormia brain is shown to contain a hypotrehalosemic hormone whose release depends on the integrity of the stomatogastric nervous system. It is possible that the hypertrehalosemic condition in cardiacectomized flies is a result of the absence of this hormone from the blood.