冷诱导亚洲玉米螟幼虫产生甘油的研究

本文以亚洲玉米螟Ostrinia furnacalis末龄老熟幼虫为材料,研究了冷诱导对血淋巴、脂肪体和脂肪体体外培养液甘油含量的影响.结果表明,室内人工饲养的滞育幼虫和非滞育幼虫在冷处理后,血淋巴中甘油浓度和脂肪体培养液中甘油含量都随冷处理天数的增加而增长,但滞育幼虫高于非滞育幼虫.与此同时,培养前后的脂肪体中甘油含量却随冷处理天数的增加而下降,而且培养前与培养后无明显差别.冷诱导的非滞育幼虫血淋巴中甘油的积累不受颈部结扎的影响.初冬田间滞育幼虫血淋巴中甘油浓度与冷处理35天的室内人工饲养滞育幼虫的甘油浓度相近;冬末田间滞育幼虫血淋巴中甘油浓度与冷处理95天的室内人工饲养滞育幼虫的甘油浓度相同,比初冬增长了50％左右.但冬末幼虫脂肪体培养液和培养前后的脂肪体中甘油含量都明显下降.以上结果说明亚洲玉米螟滞育幼虫和非滞育幼虫都具有对冷诱导产生反应的能力,它们的脂肪体都能在冷诱导之后合成与分泌甘油;所不同的是,滞育幼虫比非滞育幼虫产生甘油的能力更强,因而抗寒力也更大.     

梨小食心虫滞育与非滞育幼虫过冷却能力与体内主要生化物质含量

梨小食心虫Grapholitha molesta(Busck)是我国北方果园中重要的果树害虫,现已成为泰安肥城桃园中为害最为严重的一种食心虫。本文主要测定了梨小食心虫滞育与非滞育幼虫的过冷却能力与体内主要生化物质的含量。研究结果表明;在26℃的温度条件下,滞育幼虫的过冷却点与结冰点均低于非滞育幼虫,但差异均不显著。滞育幼虫体内的含水量、糖原和蛋白质含量均极显著低于非滞育幼虫,但是滞育幼虫体内的总脂肪、甘油和海藻糖含量均极显著高于非滞育幼虫。研究结果说明,滞育幼虫在体内生理生化代谢做了调整,以应对不利环境条件的来临。     

滞育昆虫小分子含量变化研究进展

越冬期间昆虫的滞育深度和虫体健康状态从表面难以判断,但通过虫体生化物质的测定,可以有效解决这一难题,为预测预报提供可靠信息.本文从越冬期生化物质的变化规律和主要影响影子两部分综述了国内外越冬期滞育昆虫的生化研究进展.国内外研究表明,糖原是主要的能量物质,可以转化为海藻糖、葡萄糖/果糖、甘油、山梨醇/甘露醇、肌醇、脂肪酸...     

麦红吸浆虫幼虫滞育期间糖类物质变化

分析研究了麦红吸浆虫Sitodiplosis mosellana (Gehin) 幼虫滞育期间总糖、海藻糖和糖原含量的变化。结果表明： 不同滞育年限幼虫的总糖含量无显著差异。在滞育年周期中,不同时期的滞育幼虫总糖含量明显不同。幼虫老熟入土滞育以前的总糖含量明显高于入土滞育期间。入土滞育过程中,越冬期和春季的总糖含量明显高于夏季和秋季。同期的裸露幼虫与结茧幼虫的总糖含量仅在秋季有一定的差异,其他时间基本相似。结茧幼虫滞育期间的海藻糖含量一直维持较高的水平,说明其滞育期间的糖醇积累型属于海藻糖积累型;秋季与春季糖原含量的增加可能与麦红吸浆虫的滞育解除或滞育强度的变化有一定的关系。     

滞育七星瓢虫的代谢适应与抗寒性评价

滞育是部分昆虫固有的适应逆境胁迫的遗传属性,七星瓢虫具有显著的滞育现象。本文以七星瓢虫雌成虫为试材,研究正常发育、滞育及滞育解除后3组处理试虫糖、脂、蛋白等关键代谢物质含量波动规律,总结滞育期间的代谢适应特点,解析其与过冷却能力的相关性,探索滞育对七星瓢虫逆境胁迫耐受力的促升效应,丰富七星瓢虫的滞育基础理论研究。利用物质干湿重差数法测定七星瓢虫的含水量;利用氯仿-甲醇(体积比为2∶1)法抽提除去自由水个体的脂肪;总糖、海藻糖、甘油、山梨醇及总蛋白的测定采用标准曲线法,利用SUN-II型智能昆虫过冷却点测定仪测定七星瓢虫的过冷却点(supercooling point,SCP)。结果表明,七星瓢虫滞育组含水量(58.11%±6.55%)显著低于正常发育组(68.49%±2.26%)和滞育解除组(65.84%±4.02%)(F=8.15,P0.01),滞育解除后含水量恢复至正常发育组水平;滞育组总糖(10.60±0.54μg/mg)、糖原(8.72±0.62μg/mg)、脂肪(173.66±19.01μg/mg)含量远远高于正常发育组和滞育解除组(F=46.57,P=0.0006;F=114.25,P0.0001;F=8.48,P0.01);滞育组总蛋白含量(49.20±3.80μg/mg)显著低于正常发育组(71.02±6.15μg/mg)和滞育解除组(69.45±4.66μg/mg)(F=46.57,P=0.0006);滞育组中海藻糖(1.31±0.27μg/mg)、甘油(1.74±0.50μg/mg)、山梨醇(9.84±3.02μg/mg)含量与正常发育组、滞育解除组无显著性差异(F=0.79,P=0.4946;F=1.33,P=0.3004;F=1.69,P=0.2387)。七星瓢虫在滞育条件下其过冷却点(-16.53℃±1.44℃)显著低于正常发育组(-14.07℃±1.33℃)和滞育解除组(-15.29℃±2.10℃)(F=13.47,P0.0001),经过滞育低温驯化后滞育解除组过冷却点较对照组有所降低。滞育诱发七星瓢虫发生显著的代谢适应,蛋白含量显著降低,抑制新陈代谢进程;糖脂含量显著升高,保障滞育维持及解除后发育的能量需求;七星瓢虫滞育属糖原积累型;滞育个体过冷却点大幅下降,耐寒性显著提升。     

滞育诱导温周期对桃小食心虫滞育幼虫生理指标的影响

【目的】为了明确秋季温度升高对桃小食心虫Carposina sasakii Matsumura 耐寒性的影响,针对桃小食心虫滞育过程的生理指标进行了一系列研究。【方法】在GXZ-0450型智能光照培养箱中,温度为26~18, 26~20, 26~22, 28~18, 28~20, 28~22, 30~18, 30~20和30~22℃ 9组变温下（高温10 h,低温14 h,相对湿度70%~80%,光周期为12L∶12D）分别诱导桃小食心虫滞育,再对滞育幼虫过冷却点（supercooling point, SCP）、结冰点（freezing point, FP）以及体内水、脂肪和小分子糖醇类物质含量进行测定。【结果】在适宜滞育的光照下变温不会影响桃小食心虫的滞育率,所有脱果的老熟幼虫全部进入滞育,但其生理指标却有很大差异,其中SCP和FP在较高日高温下较高（SCP：F_135,2=23.83,P<0.001;FP：F_135,2=47.64,P<0.0001）,而在较高夜低温下反而较低（SCP：F_135,2=52.88,P<0.0001;FP：F_135,2=33.34,P<0.0001）。含水量随夜低温和日高温升高显著升高（夜低温：F_135,2=13.47,P<0.0001;日高温：F_135,2=10.39,P<0.0001）。脂肪含量随夜低温升高下降（F_135,2=40.91, P<0.0001）,随日高温升高而上升（F_135,2=161.18,P<0.0001）。小分子糖醇类物质含量随温度的变化各不相同,但差异均显著（P<0.0001）：其中海藻糖、葡萄糖和赤藓糖醇的含量随夜低温升高而下降,但在日高温30℃时海藻糖和赤藓糖醇的含量却随夜温的升高而升高,葡萄糖的含量随夜低温的变化无差异;甘油随日高温的升高而显著升高,随夜低温的升高而显著下降;山梨醇和肌醇的含量随夜低温和日高温的变化差异很大。【结论】桃小食心虫不同温度下诱导滞育的幼虫SCP、FP、水、脂肪和小分子糖醇类含量存在明显差异。滞育诱导期温度对桃小食心虫幼虫的滞育生理有重要的作用,其滞育幼虫起始生理差别可能会影响其越冬。     

柞蚕蛹脂肪体和血淋巴中糖类含量动态的温度和光周期效应

本文研究了柞蚕Antheraea pernyti滞育蛹和非滞育蛹的糖类含量动态.两类柞蚕蛹血淋巴中所含糖类均为海藻糖和葡萄糖,但葡萄糖始终处于极低水平.滞育蛹的脂肪体糖原与血淋巴海藻糖之间存在相互转化的关系,这种转化受温度的制约.温度对于滞育的终止和海藻糖积累量影响很大.在保种温度范围内,滞育蛹接触低温越早,温度越低,海藻糖积累量越高.非滞育蛹即使经长期低温(0℃左右)处理,体内也不积累海藻糖,且耐寒力显著低于滞育蛹.在25℃条件下,光周期对滞育蛹和非滞育蛹的影响不同.     

大豆食心虫滞育与非滞育幼虫过冷却能力及其体内主要生化物质含量比较

【目的】本研究旨在明确大豆食心虫Leguminivora glycinivorella滞育与非滞育幼虫体内生化物质含量和保护酶活性的差异,为进一步探索大豆食心虫幼虫滞育调控的分子机制提供依据。【方法】在适温(25℃)环境下,通过控制光周期获得大豆食心虫滞育和非滞育幼虫,分别测定其过冷却点和结冰点、体内主要生化物质(糖类物质、脂类物质和可溶性蛋白)的含量以及3种保护酶[过氧化物酶(POD)、过氧化氢酶(CAT)和超氧化物岐化酶(SOD)]的活性并进行比较分析。【结果】在25℃下,大豆食心虫滞育幼虫的过冷却点(-19.20℃)和结冰点(-13.49℃)均低于非滞育幼虫的过冷却点(-16.42℃)和结冰点(-11.22℃),二者过冷却能力差异显著。滞育幼虫体内的总糖、糖原、甘油等能源物质含量均显著高于非滞育幼虫的,滞育幼虫体内总糖含量为非滞育幼虫的2.17倍,甘油含量为非滞育幼虫的1.76倍;但二者体内自由水和可溶性蛋白质含量无显著差异。同时,滞育幼虫POD和CAT活性显著高于非滞育幼虫的,但SOD活力则略低于非滞育幼虫的,无显著差异。【结论】大豆食心虫幼虫由非滞育进入滞育状态过程中,通过调节自身生理代谢使其体内糖类等生化物质含量显著升高,部分保护酶活性显著增强,进而显著提高其过冷却能力以有效应对低温等不利环境条件的来临。     

中红侧沟茧蜂寄生对寄主粘虫血淋巴糖类、脂类和蛋白质含量的影响

为揭示寄生蜂寄生对其寄主的生理调控机制, 室内对中红侧沟茧蜂Microplitis mediator寄生与未被寄生寄主粘虫Mythimna separata幼虫血淋巴中糖类、脂类和蛋白含量变化进行了测定。结果显示: 在滞育与非滞育条件下, 被寄生的粘虫血淋巴中糖原浓度均比未被寄生的粘虫高。滞育条件下寄生后12 d差异显著（P<0.05）, 被寄生粘虫糖原含量为7.93 μg/mL, 未被寄生粘虫糖原含量为4.70 μg/mL; 非滞育条件下寄生后6 d差异显著（P<0.05）, 被寄生粘虫糖原含量为14.35 μg/mL, 未被寄生粘虫糖原含量为5.47 μg/mL。海藻糖含量测定结果显示, 在滞育条件下寄生蜂对被寄生粘虫无明显影响, 而非滞育条件下影响效果差异显著（P<0.05）, 寄生后4 d被寄生粘虫海藻糖含量为46.82 μg/mL, 未被寄生粘虫含量为26.72 μg/mL。在滞育与非滞育两种条件下, 寄生与未被寄生寄主脂类和蛋白含量没有显著性差异。结果说明: 寄生蜂的存在使寄主血淋巴中的糖原含量增高; 非滞育条件是影响被寄生粘虫海藻糖含量变化主要因素; 粘虫对中红侧沟茧蜂的寄生表现相当强的适应性和忍受力。     

红脂大小蠹幼虫和成虫耐寒能力及耐寒物质的研究

为明确红脂大小蠹Dendroctonus valens LeConte的耐寒能力以及主要耐寒物质,对越冬期幼虫和成虫的过冷却点及冰点进行了测定,同时对越冬期及非越冬期幼虫和成虫体内的抗冻保护物质进行了测定.结果表明,越冬期幼虫和成虫的过冷却点差异不显著,分别为-18.34±0.26℃和-18.59±0.63℃,冰点差异显著,分别为-10.17±0.36℃和-15.90±0.70.越冬期幼虫体内脂肪、甘油、海藻糖和山梨醇含量均显著高于非越冬期幼虫,水分、糖原和蛋白质含量差异不显著;越冬期成虫体内糖原、甘油、海藻糖和山梨醇含量均显著高于非越冬期成虫,水分、脂肪和蛋白质含量差异不显著.甘油、海藻糖、山梨醇是红脂大小蠹幼虫和成虫的主要抗冻保护物质,在越冬过程中发挥重要作用;此外,脂肪在红脂大小蠹幼虫越冬过程中也发挥重要作用,糖原在红脂大小蠹成虫越冬过程中发挥重要作用.     

二化螟滞育幼虫的蛋白和核酸含量以及保护酶活性的变化

为了阐明二化螟Chilo supprressalis滞育幼虫的分子特征及滞育期间保护酶活性的变化规律, 本研究应用Trizol法、 总量DNA提取法和蛋白定量试剂盒, 测定了在长光周期16L∶8D和25℃下发育的非滞育老熟幼虫、 在短光周期12L∶12D 和25℃下诱导滞育51 d的幼虫（称为滞育0个月）、 滞育1, 2和3个月幼虫的核酸含量和总蛋白含量; 同时应用试剂盒测定了老熟幼虫、 滞育0, 1和2个月的二化螟幼虫5种保护酶（POD, CAT, SOD, LDH和ATP酶）的活性。结果表明： 滞育幼虫的总RNA含量显著低于非滞育的老熟幼虫（P<0.05）, 而滞育1, 2和3个月的幼虫之间没有显著差异（P≥0.05）。老熟幼虫的总DNA含量显著高于滞育幼虫（P<0.05）。老熟幼虫的RNA/DNA比值较低, 滞育幼虫的RNA/DNA比值较高, RNA/DNA比值随着滞育时间的推移呈现出先上升后下降的趋势。滞育期大于1个月的幼虫中蛋白含量均显著高于非滞育的老熟幼虫（P<0.05）, 而滞育1, 2和3个月的幼虫之间没有显著差异（P≥0.05）。二化螟幼虫体内5种保护酶活性随发育阶段不同而存在差异。滞育幼虫中POD, CAT和SOD的活性随滞育时间延长而逐渐增强, 滞育2个月幼虫中的活性最高, 而非滞育老熟幼虫中的活性最低; LDH和ATP酶的活性则相反, 非滞育老熟幼虫中的活性最高, 滞育2个月幼虫中的活性最低。这些结果说明, 总RNA和DNA含量降低、 RNA/DNA比值先升后降、 总蛋白含量升高以及保护酶活性的变化是二化螟幼虫滞育过程中的主要生理特征。     

Glycerol accumulation in developmentally arrested pupae of Papilio machaon obtained by brain removal

Brains were removed from non-diapausing pupae of Papilio machaon within 24 hr after pupation. The developmentally arrested pupae were examined for glycerol metabolism by comparison with naturally diapausing pupae. The decerebrate non-diapausing pupae accumulated appreciable amounts of glycerol (13.0 mg/ml haemolymph) during exposure to 5°C for 2 months. However, this amount was considerably lower than that accumulated in the naturally diapausing pupae (24.5 mg/ml) under the same conditions. A difference was also observed in the initial level of the glycogen in the fat body. The naturally diapausing pupae contained about 105 mg/g glycogen, while the decerebrate non-diapausing pupae contained only about 70 mg/g, one day after pupation.     

Effects of diapause and cold-acclimation on the avoidance of freezing injury in fat body tissue of the rice stem borer, Chilo suppressalis Walker

Overwintering freeze-tolerant larvae of Chilo suppressalis can survive at -25 degrees C, but non-diapausing larvae cannot. We reported earlier that to prevent intracellular freezing, which causes death in overwintering larvae of the Saigoku ecotype distributed in southwestern Japan, water leaves and glycerol enters fat body cells through water channels during freezing. However, it is still unclear how diapause and low-temperature exposure are related to the acquisition of freeze tolerance. We compared the extent of tissue damage, accumulation of glycerol, and transport of glycerol and water in fat body tissues between cold-acclimated and non-acclimated non-diapausing and diapausing larvae. The tissue from cold-acclimated diapausing larvae could survive only when frozen in Grace's insect medium with 0.25 M glycerol at -20 degrees C. The protection provided by glycerol was offset by mercuric chloride, which is a water-channel inhibitor. Fat body tissue isolated from non-acclimated diapausing larvae was injured by freezing even though glycerol was added to the medium, but the level of freezing injury was significantly lower than in non-diapausing larvae. Radiotracer assays in cold-acclimated diapausing larvae showed that during freezing, water left the cells into the medium and glycerol entered the cells from the medium at the same time. Therefore, in Saigoku ecotype larvae of the rice stem borer, both diapause and cold-acclimation are essential to accumulate glycerol and activate aquaporin for the avoidance of freezing injury.     

Metabolic dynamics across prolonged diapause development in larvae of the sawfly,Cephalcia chuxiongica (Hymenoptera: Pamphiliidae)

Nutrient metabolism is crucial for the survival of insects through the diapause. However, little is known about the metabolic mechanism of prolonged diapause. The sawfly, Cephalcia chuxiongica (Hymenoptera: Pamphiliidae), is a notorious defoliator of pine trees in southwest China. One of the distinguishing biological characteristics of this pest is the prolonged diapause of about 1.5 years. In this study, the body lipid, carbohydrate (total body sugar, glycogen, trehalose, and glucose), protein, and glycerol contents were measured in diapausing larvae of C. chuxiongica. The results showed that the changes of biochemical composition in C. chuxiongica are associated with the diapause initiation, maintenance, and termination phases. During the initiation phase, trehalose, glucose, and glycerol increased significantly, but glycogen decreased sharply. In general, the lipid, carbohydrate, and glycerol levels decreased gradually across the maintenance phase. At termination phase, the contents of glycogen and lipid persistently decreased, while an increase of trehalose, glucose, and glycerol contents were detected. The protein level was significantly higher at maintenance phase than at initiation and termination phases. It was also found that elevation of trehalose, glucose, and glycerol contents occurred in winter. These implies that the metabolites with altered levels in diapausing larvae of C. chuxiongica are responsible for maintaining a prolonged development and overwintering.     

Hydrolysis of juvenile hormone in diapausing and non-diapausing larvae of the southwestern corn borer,Diatraea grandiosella

Summary The role of juvenile hormone (JH) esterases in relation to the diapause state of the southwestern corn borer,Diatraea grandiosella, was examined. The facultative larval diapause of this insect is dependent upon the presence of JH. Plasma, fat body, midgut, and body wall extracts metabolized [³H]JH I and [³H]JH III to JH-acid in vitro. JH-diol, JH-acid-diol, or conjugated polar metabolites were not detected. A longer half life of [³H]JH I was found in vitro in the plasma of diapausing larvae than in that of non-diapausing larvae. Although JH hydrolytic activity was relatively low in the plasma of pre-diapausing and diapausing larvae, systematic changes were observed suggesting that JH esterases may be involved in regulating the JH titer during this period. The JH hydrolytic activity found in the plasma of diapausing larvae was 3 to 5 times lower than that found in the plasma of mid-last instar non-diapausing larvae. Gel filtration profiles obtained from the plasma of diapausing and non-diapausing larvae suggested that JH esterases and -naphthyl-acetate esterases are different enzymes. Multiple overlapping peaks of JH hydrolytic activity with an apparent molecular weight range of 43,000 to 75,000 were detected, whereas 2 separate peaks of -naphthyl-acetate hydrolytic activity (apparent mol. wt. ca. 54,000, and 120,000) were detected. Gel filtration of supernatants of fat body indicated that JH was hydrolyzed at a lower rate by the fat body of pre-diapausing larvae than by that of non-diapausing larvae.     

Proteins of the fat body of non-diapausing and diapausing larvae of the southwestern corn borer, Diatraea grandiosella: Effect of juvenile hormone

The proteins of the fat body of non-diapausing, pre-diapausing, and newly-diapaused larvae of the southwestern corn borer, Diatraea grandiosella, were examined. Since a low titre of juvenile hormone (JH) is present in the haemolymph throughout the final instar of non-diapausing larvae, the hormone does not appear to stimulate the pre-metamorphic synthesis of proteins. In contrast, the high titre of JH in the haemolymph during the final instar of pre-diapausing larvae appears to stimulate the synthesis of selected proteins. For example, pre-diapausing larvae store in their fat body a low molecular weight protein which has been named the ‘diapause-associated protein’. When non-diapausing larvae were treated topically with C₁₇-JH or a JH mimic, from 50 to 70% entered a diapause-like state as fully grown larvae. These hormone-treated larvae accumulated the diapause-associated protein and a high molecular weight protein in their fat bodies. Both of these proteins were shown to be released from the fat body of newly-diapaused larvae in vitro, and may function in the haemolymph during diapause. The high molecular weight protein, isolated from the haemolymph, was shown to contain neutral and polar lipids, including biochromes. Its storage in the fat body and release into the haemolymph may be essential for the transport of lipids during diapause. The fat body proteins of newly-diapaused larvae of the southern cornstalk borer, Diatraea crambidiodes, were also examined electrophoretically. They were found to contain a similar protein pattern to that of D. grandiosella, including the presence of a diapause-associated protein.     

Water and carbohydrate levels at different developmental stages and dynamics in hibernating pupae of Pieris melete (Lepidoptera: Pieridae)

For insight into the physiological indicators of diapause in Pieris melete, water and carbohydrate (glycogen and trehalose) levels were measured under both natural and laboratory conditions. The highest water content (3.71–3.79 mg/mg dry weight) was found in larvae and developing pupae, which was substantially higher than in diapausing pupae (2.59 mg/mg dry weight). Water content was almost stable during diapause, except for individuals approaching diapause termination (3.43–3.58 mg/mg dry weight). The total carbohydrate level was significantly higher in pre‐pupae (47.41 μg/mg) compared to larvae (22.80 μg/mg) and developing pupae (21.48 μg/mg). The highest level of trehalose was detected in winter diapausing pupae, and no trehalose was found in larvae or developing pupae. Levels of glycogen were highest in pre‐pupae and lowest in diapausing pupae. Levels of total carbohydrate decreased as diapause proceeded, and no significant changes were found in trehalose levels for diapausing pupae under natural conditions or treated for 60–90 days at 5°C. Pupae treated at 20°C for 60–90 days had significantly lower levels of trehalose than those treated for 30 days. Glycogen content was relatively stable at 5°C, but increased after treatment under natural conditions and 20°C for more than 60 days. These results suggest that the dynamics of water and carbohydrate levels are potential physiological diapause indicators, which show metabolic differences between trehalose and glycogen during diapause development.     

The biochemical effects of potassium chloride on the silkworm, （ Bombyx mori L.）

The supplementation with 50, 100 and 150μg/mL potassium chloride to the fifth instar larvae of the silkworm Bombyx mori on fat body glycogen, protein, total lipids and haemolymph protein and trehalose were analyzed. The fat body glycogen and protein and haemolymph protein were increased significantly in all the treated groups; whereas fat body total lipids increased only in 100 and 150μg/mL and haemolymph trehalose increased only in 150μg/mL potassium chloride-treated groups when compared with those of the corresponding parameters of the carrier controls.