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。     

感染布氏白僵菌后油松毛虫血淋巴中海藻糖酶活性、海藻糖和葡萄糖含量的变化

为了揭示病原真菌白僵菌Beauveria侵染昆虫过程中如何利用虫体内糖类物质作为自身营养, 本研究测定了布氏白僵菌Beauveria brongniartii (Sacc.) Petch （2382菌株）感染油松毛虫Dendrolimus tabulaeformis Tsai et Liu幼虫后, 虫体血淋巴中酸性海藻糖降解酶活性及海藻糖和葡萄糖含量的变化。油松毛虫4龄幼虫感染菌株孢子悬浮液后, 血淋巴中酸性海藻糖降解酶的活性明显高于对照组, 感染后第3天酶活性达到最大值（0.2786 U/mg）, 此后第4-6 天酶活性逐渐降低; 染菌后的6 d中, 血淋巴中海藻糖含量显著低于对照组, 同样在感染后第4天其含量逐渐降低, 第6天时降到最低值。相比之下, 处理组血淋巴中的葡萄糖含量显著高于对照组; 处理组其含量在第1-3天内呈现快速升高趋势, 在第3天达到最大值（7.7615 mmol/L）, 然后逐渐降低。结果说明, 白僵菌侵入昆虫血淋巴后, 菌株代谢产生酸性海藻糖降解酶, 将血淋巴中的海藻糖水解成为葡萄糖, 然后为真菌利用, 破坏了虫体内的血糖平衡, 这是一个相互连接的生理代谢和生化反应过程。     

Involvement of adipokinetic hormone in the homeostatic control of hemolymph trehalose concentration in the larvae of Bombyx mori

Prior to wandering, 5th instar larvae of the silkworm, Bombyx mori, maintain constant hemolymph titers of trehalose. Head ligation of day 3, 5th instar larvae significantly decreased the hemolymph trehalose concentrations, but the concentrations did not decrease in starved larvae. After being diluted by replacement of larval hemolymph with insect Ringer's solution, the trehalose concentrations recovered the initial levels in 90 min in the non-ligated larvae, while they were not restored in 90 min in the neck-ligated larvae. These results suggest that a head factor(s) with hypertrehalosemic activity is involved in the homeostatic control of hemolymph trehalose concentration. When adipokinetic hormone (AKH) was injected into neck-ligated larvae, the trehalose concentrations increased in 2 h and decreased thereafter. Repeated injections of AKH every 4 h maintained the concentrations for 12 h. These findings suggest that AKH induces a hypertrehalosemic response and is involved in the homeostasis of hemolymph trehalose concentration in the larval feeding period.     

Presence and regulation of trehalose in the body of adult Phormia regina

Trehalose, the major blood sugar of Phormia regina, is present within its tissues in an amount exceeding that in the total blood volume. A major part of the reserve is found in the abdominal fat body. An investigation of trehalose regulation, pursued with the use of a trehalose tolerance test, indicates that within a period of 4 h the adult fly can remove from its blood amounts of this sugar in excess of twice its normal level. The surplus is dealt with in an as yet unknown way, being either sequestered in the tissues (not as trehalose or glucose), metabolized, or excreted in a form other than trehalose or glucose. The process is regulated by the head, and a link between the body and the head must be maintained throughout the entire period of activity.     

Feeding glucose or sucrose, but not trehalose, suppresses the starvation-induced premature pupation in the yellow-spotted longicorn beetle, Psacothea hilaris

Under 25 degrees C and a long-day photoperiod, starvation induces premature pupation in 4th instar Psacothea hilaris larvae exceeding a threshold weight of 180 mg, resulting in the formation of small but morphologically normal adults. To investigate possible mechanisms underlying this phenomenon, we first measured the hemolymph trehalose and glucose levels of starved larvae. When larvae were starved after 4 days of feeding (attaining the threshold weight), glucose levels decreased 4-fold within the next 24 h, while trehalose levels, after a temporary slight decrease, increased remarkably to reach a peak just before the prepupa stage. The effects of ingesting various nutrients on the developmental fate and the hemolymph sugar titers of starving larvae were then examined. Feeding on agar blocks containing sucrose or glucose totally suppressed the occurrence of premature pupation, while trehalose, fructose, casein and starch were ineffective. Feeding on glucose or trehalose resulted in a 6-fold decrease in hemolymph glucose levels and remarkably elevated trehalose levels. Since feeding on glucose and trehalose induced similar changes in hemolymph sugar titers but trehalose was not effective in suppressing premature pupation, glucose may have exhibited its effects via gustatory mechanisms.     

Dietary nutrient levels regulate protein and carbohydrate intake,gluconeogenic/glycolytic flux and blood trehalose level in the insect<Emphasis Type="Italic"> Manduca sexta</Emphasis> L.

This study examined the effects of dietary casein and sucrose levels on nutrient intake, and distinguished the effects of carbohydrate and protein consumption on growth, fat content, pyruvate metabolism and blood trehalose level of 5th instar Manduca sexta larvae. Growth increased with increasing casein consumption but was unaffected by carbohydrate intake. Fat content also increased with carbohydrate consumption, but on carbohydrate-free diets fat content increased with increased protein consumption. Blood trehalose level and pyruvate metabolism were examined by nuclear magnetic resonance spectroscopy analysis of blood following administration of (3-(13)C)pyruvate. On diets containing sucrose, blood trehalose increased with increasing carbohydrate intake, and on most diets trehalose was synthesized entirely from dietary sucrose. Pyruvate cycling, indicated by the alanine C2/C3 (13)C enrichment ratio, increased with carbohydrate consumption reflecting increased glycolysis, and pyruvate decarboxylation exceeded carboxylation on all sucrose diets. Larvae that consumed <75 mg/day sucrose were gluconeogenic, based on the [2 (trehalose C6)(Glx C3/C2)]/alanine C2] (13)C enrichment ratio. On carbohydrate-free diets, blood trehalose levels were low and maintained entirely by gluconeogenesis. Blood trehalose level increased with increasing protein intake. Pyruvate cycling was very low, although many insects displayed higher levels of pyruvate decarboxylation than carboxylation. All gluconeogenic larvae displayed alanine (13)C enrichment ratios <0.35 and had blood trehalose levels <50 mM.     

Relation of blood composition to age in the larval female house cricket, Acheta domesticus

The blood volume, osmolality, and sugar concentration increase; the blood protein and lipid concentration decrease; and the blood ions and NPS concentration do not change during apolysis from the 7th to 8th instar of larval Acheta domesticus. The patterns of change in all blood constituents are basically identical in both of the last two larval instars. Blood volume increase is directly related to growth, but not directly to total body water. Blood protein concentration increases in exact relation to growth, resulting in a doubling of concentration by midinstar and a small decrease over the last 2 to 3 days. The concentration of clottable protein remains constant; the soluble protein concentration increase probably providing cuticular proteins prior to and following ecdysis. Blood lipid concentration increases steadily throughout both instars, even during the non-feeding phase. Total blood carbohydrate concentration decreases greatly in the first 2 days of an instar, then remains relatively constant for the remainder of the instar. Blood trehalose concentration is 85% of the total carbohydrate concentration throughout the instar, but drops to 65% with a corresponding increase in ‘other sugars’ with the onset of apolysis on the last day. Growth demands probably exceed dietary supply of amino acids resulting in a 50% decrease in NPS concentration in the first half of the instar, then NPS concentration increases in spite of a declining feeding rate because growth demands cease. Within the normal blood ion lability range, the principle blood ions, sodium and chloride, vary in an inverse proportion to NPS and sugar concentration at least in the first two-thirds of the instar. Thus blood osmolality is constant except for an unexplained drop in the last 2 days of an instar.     

Pyruvate cycling and implications for regulation of gluconeogenesis in the insect, Manduca sexta L

Pyruvate cycling was examined in the insect Manduca sexta L. (2-(13)C)pyruvate was injected into 5th instar larvae maintained on a semisynthetic high sucrose, low sucrose, or sucrose-free diet. Pyruvate cycling and gluconeogenesis were determined from the distribution of (13)C in blood metabolites, including trehalose, the blood sugar of insects, and alanine. Pyruvate cycling was evident from the (13)C enrichment of alanine C3, synthesized by transamination of pyruvate following carboxylation to oxaloacetate and cycling through phosphoenolpyruvate. Based on the relative (13)C enrichments of alanine C2 and C3, insects maintained on the high sucrose diet displayed higher levels of cycling than insects on the other diets. Insects on all the diets, when subsequently starved, displayed low levels of cycling. Gluconeogenesis was evident in insects on sucrose-free or low sucrose diets from the selective (13)C enrichment in trehalose. The level of gluconeogenesis relative to glycolysis was indicated by the (13)C enrichment of trehalose C6 and alanine C3, both enrichments metabolically derived in the same manner. Insects starved after maintenance on the sucrose-free or low sucrose diets remained glucogenic. Insects on the high sucrose diet were not glucogenic, and subsequent starvation did not induce gluconeogenesis. The results indicate that pyruvate kinase plays a critical role in regulating the gluconeogenic/glycolytic balance, and that inhibition of pyruvate kinase is a principal regulatory event during induction of de novo trehalose synthesis. Gluconeogenesis failed to maintain homeostatic levels of blood trehalose, supporting the conclusion that blood sugar level may be important for mediating nutrient intake. Possible factors involved in the regulation of gluconeogenesis in insects are discussed.     

Carbohydrate metabolism in Manduca sexta during late larval development

The carbohydrate metabolism in Manduca sexta underwent significant changes during late larval development. Approximately 10% of fat body glycogen phosphorylase was active during the feeding period of the 5th instar, pharate-pupal development and after the pupal moult; it is concluded that glycogen synthesis prevailed. During the last larval and the pupal moult, as well as the wandering stage the percentage of active phosphorylase was significantly increased indicating that fat body glycogen stores were broken down to supply substrates to meet the demands of carbohydrate metabolism. In the course of the last larval moult and the wandering stage the fat body glycogen content decreased significantly from about 300 to about 200 μg mg⁻¹ dry mass substantiating that carbohydrates were released from the fat body. Prior to phosphorylase activation, the concentrations of total haemolymph sugars decreased significantly from about 12 to about 6 mg trehalose equivalents ml⁻¹ (last larval moult) and from about 18 to about 12 mg ml⁻¹ (wandering stage), and increased again slightly when phosphorylase was activated. The haemolymph glucose concentration decreased significantly from about 1.1 to 0.3 mg ml⁻¹ (last larval moult) and in the course of the 5th-instar feeding period from about 1.1 to 0.2 mg ml⁻¹, and remained at this level until the beginning of adult development. The amount of chitosan present in the cuticle increased steadily during the feeding period of the 5th instar from about 10 to 110 mg. It appears that fat body glycogen might be broken down during the last larval moult and the wandering period to provide substrates for chitin synthesis. A dramatic decrease in the amount of chitosan was observed prior to the pupal moult.     

Blood sugar formation due to abnormally elevated gluconeogenesis: aberrant regulation in a parasitized insect, Manduca sexta Linnaeus.

Alterations of carbohydrate metabolism associated with parasitism were examined in an insect, Manduca sexta L. In insect larvae maintained on a low carbohydrate diet gluconeogenesis from [3-13C]alanine was established from the fractional 13C enrichment in trehalose, a disaccharide of glucose and the blood sugar of insects and other invertebrates. After transamination of the isotopically substituted substrate to [3-13C]pyruvate, the latter was carboxylated to oxaloacetate ultimately leading to de novo glucose synthesis and trehalose formation. Trehalose was selectively enriched with 13C at C1 and C6 followed by C2 and C5. 13C enrichment of blood sugar in insects parasitized by Cotesia congregata (Say) was significantly greater than was observed in normal animals. The relative contributions of pyruvate carboxylation and decarboxylation to trehalose labeling were determined from the 13C distribution in glutamine, synthesized as a byproduct of the tricarboxylic acid cycle. The relative contribution of carboxylation was significantly greater in parasitized larvae than in normal insects providing additional evidence of elevated gluconeogenesis due to parasitism. Despite the increased gluconeogenesis in parasitized insects the level of blood sugar was the same in all animals. Because de novo glucose synthesis does not normally maintain blood sugar level in insects maintained under these dietary conditions the findings suggest an aberrant regulation over gluconeogenesis. The 13C labeling in trehalose was nearly symmetric in all insects but the mean C1/C6 13C ratio was higher in parasitized animals suggesting a lower activity of the pentose phosphate pathway that brings about a redistribution of 13C in trehalose following de novo glucose synthesis. Additional studies with insects maintained on a high carbohydrate diet and administered [1,2-13C2]glucose confirmed a decreased level of pentose cycling during parasitism consistent with a lower level of lipogenesis. It is suggested, however, that the pentose pathway may facilitate the synthesis of trehalose from dietary carbohydrate by directing hexose phosphate cycled through the pathway to the production of energy.     

Blood sugar formation from dietary carbohydrate is facilitated by the pentose phosphate pathway in an insect Manduca sexta Linnaeus

Dietary carbohydrate, the principal energy source for insects, also determines the level of the blood sugar trehalose. This disaccharide, a byproduct of glycolysis, occurs at highly variable concentrations that play a key role in regulating feeding behavior and growth. Little is known of how developing insects partition the metabolism of dietary carbohydrate to meet the needs for blood trehalose, ribose sugars and NADPH, as well as energy production. This study examined the effects of varying dietary sucrose levels between 3.4 and 34 g/l in an artificial diet on growth rate, depot fat content and blood sugar formation from (13)C-enriched glucose in Manduca sexta. (2-(13)C)Glucose or (1,2-(13)C(2))glucose were administered to larvae by injection and after 6 h blood was analyzed by nuclear magnetic resonance spectroscopy. [2-(13)C]Trehalose was the principal product of [2-(13)C]glucose, but trehalose was also (13)C-enriched at C1 and C3, demonstrating activity of the pentose phosphate pathway. The trehalose C1/C2 (13)C-enrichment ratio, a measure of the substrate cycled through the pentose pathway, significantly increased with increasing dietary sugar, and reached a mean of 0.22 at the highest level. Blood trehalose concentration increased from approximately 38 mM at the lowest dietary carbohydrate level to 75 mM at the highest. Moreover, blood trehalose, growth rate and depot fat all increased in precisely the same way in relation to the level of pentose cycling. Based on the multiplet (13)C-NMR signal structure of trehalose synthesized from [1,2-(13)C(2)]glucose by insects maintained on a high carbohydrate diet, it was established that the formation of trehalose from glucose phosphate derived directly from the administered substrate, with no involvement of the pentose pathway, was greater than that from glucose phosphate metabolized through the pentose pathway prior to trehalose synthesis. On the other hand, glucose phosphate first metabolized through the pentose pathway contributed more to pyruvate formation than did glucose phosphate formed from the labeled substrate metabolized directly to pyruvate via glycolysis; this finding based on the multiplet (13)C-NMR signal structure in alanine derived from pyruvate. The results suggest that as dietary carbohydrate increases blood sugar synthesis from glucose phosphate derived directly from dietary sugar is facilitated by the pentose pathway which provides an increasing amount of substrate to pyruvate formation.     

Glucogenic blood sugar formation in an insect Manduca sexta L.: asymmetric synthesis of trehalose from 13C enriched pyruvate

Gluconeogenesis and blood sugar formation were examined in Manduca sexta, fed carbohydrate- and fat-free diets with varying levels of casein. De novo carbohydrate synthesis was examined by nuclear magnetic resonance spectroscopy of the 13C enrichment in blood trehalose and alanine derived from (2-(13)C)pyruvate and (2,3-(13)C(2))pyruvate administered to 5th instar larvae. Gluconeogenic flux and blood trehalose concentration were positively correlated with protein consumption. On all diets, the 13C distribution in trehalose was asymmetric, with C6 more highly enriched than C1. The C6/C1 13C enrichment ratio, however, decreased with increased protein consumption and gluconeogenic flux. Although the asymmetric 13C enrichment pattern in trehalose is consistent with pentose cycling via the pentose phosphate pathway following de novo synthesis, experiments employing [2,3-(13)C(2)]pyruvate demonstrated that pentose cycling is not detected in insects under these nutritional conditions. Analysis of the multiplet NMR signal structure in trehalose due to spin-spin coupling between adjacent 13C enriched carbons showed the absence of uncoupling expected by pentose phosphate pathway activity. Here we suggest that the asymmetric 13C distribution in trehalose results from a disequilibrium of the triose phosphate isomerase-catalyzed reaction.     

Regulation of energy metabolism in Saccharomyces cerevisiae. Relationships between catabolite repression, trehalose synthesis, and mitochondrial development.

Changes in trehalose accumulation and in cytochromes during diauxic growth in glucose medium were examined in a normal Saccharomyces cerevisiae strain. While no appreciable disaccharide accumulation occurred during most of the logarithmic phase, a rapid synthesis took place during the final stages. The intrinsic capacity of cells to accumulate trehalose was also determined under nonproliferating conditions, in glucose medium lacking a nitrogen source. Cells harvested at an early growth stage had a much lower trehalose accumulation capacity than cells taken after glucose was exhausted from the culture medium. A high trehalose accumulation capacity could also be obtained at any growth stage by using maltose or galactose as carbon source. Since cells grown under various conditions exhibit a correlated change in cytochrome development and in trehalose accumulation capacity, it was concluded that the level of glucose repression determines the concentration and/or state of activation of the trehalose synthetase-trehalase complex. Independent control of trehalose accumulation capacity and mitochondrial biogenesis by the level of glucose repression was shown in two ways: by demonstrating derepression of trehalose accumulation without development of cytochromes a and c in microaerobic cells, and by showing repression-dependent changes in a cytoplasmic respiration-deficient (ρ^?) mutant, which lacked functional mitochondria. Therefore, the capacity of a cell to accumulate trehalose is not regulated solely by the supply of ATP generated by oxidative phosphorylation.     

Carbohydrate metabolism during starvation in the silkworm Bombyx mori

The effect of starvation on carbohydrate metabolism in the last instar larvae of the silkworm Bombyx mori was examined. Trehalose concentration in the hemolymph increased slightly during the first 6 h of starvation and decreased thereafter, whereas glucose concentration decreased rapidly immediately after diet deprivation. Starvation-induced hypertrehalosemia was completely inhibited by neck ligation, suggesting that starvation stimulates the release of a hypertrehalosemic factor(s) from the head. The percentage of active glycogen phosphorylase in the fat body increased within 3 h of starvation and its glycogen content decreased gradually. These observations suggest that production of trehalose from glycogen is enhanced in starved larvae. However, hypertrehalosemia during starvation cannot be explained by the increased supply of trehalose into hemolymph alone, as similar changes in phosphorylase activity and glycogen content in the fat body were observed in neck-ligated larvae, in which hemolymph trehalose concentration did not increase but decreased gradually. When injected into larvae, trehalose disappeared from hemolymph at a rate about 40% lower in starved larvae than neck-ligated larvae. The hemolymph lipid concentration increased during starvation, suggesting that an increased supply of lipids to tissues suppresses the consumption of hemolymph trehalose and this is an important factor in hypertrehalosemia.     

Carbohydrate metabolism in starved fifth instar larvae of Manduca sexta

The influence of starvation on carbohydrate metabolism in fifth instar larvae of Manduca sexta was studied. The percentage of active fat body glycogen phosphorylase increased from 10% to approximately 50% within 3 h of starvation; afterward the enzyme was slowly inactivated. The increase of phosphorylase activity might have been caused by a peptide(s) from the CC. The amount of fat body glycogen in starved animals decreased over 24 h by approximately 20 mg. The released glucose molecules seem to be converted mainly to trehalose because the hemolymph trehalose concentration in starved animals was always slightly higher than in the fed controls, and the glucose concentration decreased even when phosphorylase was activated. The chitosan content in starved larvae increased during the first 9 h of treatment to the same extent as in fed controls. It is suggested that fat body glycogen phosphorylase was activated during starvation to provide substrates for chitin synthesis and energy metabolism.     

Changes of phosphatidylserine distribution in human red blood cells during the process of loading sugars

The plasma membrane of red blood cells permits sugars to be loaded into the cytoplasm simply by incubation in a suitable buffer solution containing the sugar. This may provide some hope for the freeze-drying of human red blood cells. However, the effect of the loading process on red blood cells has not been fully investigated. The exposure of phosphatidylserine (PS) on the surface of the cell can be recognized by macrophages and result in shortened circulation in vivo. This study evaluates the effects of the concentration, the incubation time, and the temperature of exposure of human red blood cells to extracellular trehalose or glucose. Exposure of PS was demonstrated by annexin V labeling. It was shown that the efficiency of loading of glucose was significantly greater than that of trehalose. The loading efficiency of both sugars increased with increase in extracellular sugar concentration, prolongation of incubation time, and increase of incubation temperature. The percentages of cells with exposed PS and of damaged cells were dependent on the extracellular sugar concentration, the incubation time, and the temperature. With an extracellular glucose concentration of 0.8M, the percentage of cells with exposed PS was more than 80% and significantly higher than that of red blood cells loaded with trehalose (approximate 20%, P<0.01). As the incubation time was prolonged, the percentage of PS exposure and of damaged cells also increased. After incubation for 5h, the percentage of red cells with exposed PS following loading with glucose was more than 80% and significantly higher than that of cells loaded with trehalose (40%, P<0.01). In addition, the incubation temperature had a major effect on PS exposure. The percentage of cells with PS exposure and the proportion of damaged cells increased with increase of incubation temperature. At 37 degrees C, the percentage of cells with exposed PS and of damaged cells after loading with glucose was more than 80% and significantly higher than that of cells loaded with trehalose (P<0.01). However, when the temperature was below 25 degrees C, the percentage of cells with exposed PS and of damaged cells after loading with glucose or trehalose were both less than 10%. In conclusion, the loading efficiency for glucose was higher than that for trehalose, but the lesser effect of trehalose on exposure of PS suggests that it can maintain the asymmetrical distribution of membrane phospholipids and the intracellular trehalose can increase the osmotic tolerance of cells.     

Evidence that the fertilization envelope blocks sperm entry in eggs of Xenopus laevis: interaction of sperm with isolated envelopes.

Single-celled myxamoebae undergo differentiation into either stalk cells or spore cells during a 24-hr period in Dictyostelium discoideum. This study employed ultramicrochemical techniques and enzymatic cycling to assess the presence of cell-specific events in spore and stalk cells. Freeze-dried sections of one organism were assayed in 0.1 μl of reaction mixture. This method was used to determine the extent of localization of trehalose in spore cells and stalk cells during development.Trehalose was low in the early stages of differentiation to about 20 hr when the level started to increase. In developing spore cells, the trehalose level increased sixfold during the last 5 hr of development. Likewise, the entire stalk contained trehalose when the stalk was first formed. At mature sorocarp, trehalose levels were the same in spores and the apex of the stalk. There was a decreasing gradient of trehalose down the stalk. The bottom one-fourth of the stalk was devoid of this disaccharide. Therefore, trehalose was degraded from an area of the stalk where it was localized earlier in development.The results of this investigation negate the assumption that trehalose is never present in the stalk. Although trehalose was found in spore cells, prestalk cells also contained high trehalose levels. The stalk cell-specific trehalose was not retained during differentiation, however, but was apparently degraded in the mature stalk cell.     

Lunar phase influence on the glycemia of worker honeybees

The variations of the concentrations of trehalose and glucose, the major components of the haemolymph of emerging worker honeybees, have been examined with respect to the lunar phase. Two series of experiments were performed independently, from April to June and from July to September respectively. The results revealed significant peakings for both carbohydrates at full moon and at new moon, and also a minor peak at last quarter. The data obtained for trehalose in the July-September period are consistent with the existence of a circaseptan subcomponent of period tau congruent to 132h.     

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...     

Sensitivities to juvenile hormone and ecdysteroid in the diapause larvae of Omphisa fuscidentalis based on the hemolymph trehalose dynamics index

The final instar larva of the bamboo borer, Omphisa fuscidentalis, is in diapause for 9 months from September to the following June. Trehalose and ecdysteroid concentrations in hemolymph were measured through the larval diapause period and in the pupal stage. The ecdysteroid concentration remained low until November, followed by a gradual increase to about 30 ng/ml in May. The trehalose concentration remained at levels ranging between 40-50 mM until May, and decreased to an almost undetectable level after pupation. Since a juvenile hormone analogue (JHA), methoprene, is capable of terminating diapause by stimulating larval prothoracic glands, we examined its effects on ecdysteroid and trehalose concentrations in larvae in December and February. The hemolymph ecdysteroid increased more quickly in February than in December, indicating that the sensitivity of the prothoracic glands to JHA increased towards the end of diapause termination. Similarly, hemolymph trehalose in February decreased within a few days after JHA application, while in December the decrease occurred in the third week. Exogenous 20-hydroxyecdysone (20E) caused a decrease in trehalose concentration in a dose-dependent manner. The effective dose of 20E, however, did not change from January until April, implying that the sensitivity of tissue(s) to 20E may not change until the end of diapause. Taken together, our results suggest that the sensitivities of tissues to JH and 20E do not increase simultaneously with the progress of diapause development and that termination of larval diapause is not associated simply with the restoration of hormone deficiencies.