七星瓢虫成虫脂肪体核酸代谢与生殖滞育的关系

本文以微量萤光法测定七星瓢虫成虫繁殖期、滞育期脂肪体核酸、蛋白含量的变化,结果表明:繁殖期雌虫卵巢发育Ⅰ和Ⅱ级时RNA/DNA比值分别为2.47和4.50;卵巢发育至Ⅲ级时RNA/DNA比值出现高峰为8.44,Ⅳ级时降为3.60,产卵后显著下降至1.76。所以脂肪体RNA/DNA比值可做为卵黄蛋白合成的一项指标。 成虫羽化后,以短光照(每日9小时光照,15小时黑暗)诱导成虫滞育,测定预滞育期RNA/DNA比值及蛋白质含量分別为3.16及59微克/毫克脂肪体;进入滞育期则分别降为1.24和14微克/毫克脂肪体;滞育结束后RNA/DNA比值上升为7.04,蛋白含量为133微克/毫克脂肪体。 成虫繁殖期与滞育期不同阶段脂肪体核酸、蛋白量的差异反映卵黄蛋白合成水平。核酸蛋白质含量低可做为滞育出现的信号。而滞育结束后RNA/DNA及蛋白含量的增加,可做为滞育结束的一个生化指标。     

柞蚕卵巢中核酸和蛋白质的分布与含量的变化

本文报道柞蚕卵巢亚细胞组分中核酸和蛋白质的分布与含量变化。首先以差速离心盼方法从卵巢匀浆中分离出细胞核、重线粒体、轻线粒体、重微粒体、轻微粒体和105,000g上清六个组分,然后分别测定了各种组分中的DNA、RNA和蛋白质的含量。 结果表明,卵巢DNA主要分布在细胞核组分中(约占75%以上);RNA在佩粒体中含量较离(约占20—51%);蛋白质则主要分布于105,000g上清组分中(约占56—83%)。卵巢中核酸和蛋白质含量(毫克/头)在滞育蛹期很低,随着卵巢的发育迅速增长。DNA在发育蛹4期最高,比滞育蛹期增长61倍;RNA在发育蛹5期最高,比滞育蛹期增长144倍;蛋自质在成虫期达到高峰,约比滞育蛹期增长490倍。并讨论了核酸和蛋白质的含量变化与卵巢细胞分裂分化之间的关系。 为了获得进一步的生化资料,对不同时期的柞蚕卵巢105,000g上清组分中的蛋白质进行了聚丙烯酰胺凝获也泳和SDS-电泳的分析。初步推测柞蚕卵巢中卵黄蛋白亚基之一的分子量大约为200,000道尔顿。     

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。     

草地螟滞育幼虫的蛋白和核酸含量变化

为了阐明草地螟Loxostege sticticalis 滞育的分子调控基础, 本研究应用Trizol法、 DNA和蛋白质定量试剂盒、 SDS-PAGE电泳技术分别对进入滞育1, 2, 3和4个月、 解除滞育以及非滞育草地螟老熟幼虫中的核酸含量、 总蛋白含量和组分的变化进行了测定。结果表明： 滞育不同月份幼虫的总RNA含量显著低于非滞育幼虫的总RNA含量（P＜0.05）; 解除滞育幼虫的总RNA含量显著高于滞育2, 3和4个月的幼虫, 但仍显著低于非滞育的对照组。滞育不同月份、 非滞育以及解除滞育幼虫的总DNA含量没有显著差异（P＞0.05）。RNA/DNA比值随滞育的开始而显著下降, 随着滞育的结束而显著上升。滞育不同月份的幼虫总蛋白含量显著高于非滞育幼虫的总蛋白含量（P<0.05）, 但解除滞育与非滞育幼虫的总蛋白含量无显著差异。利用SDS-PAGE电泳分析发现滞育幼虫体内存在滞育关联蛋白, 蛋白条带在24 kDa左右, 但非滞育和已经解除滞育的幼虫则没有该蛋白条带。这些结果表明, 总RNA含量的降低、 RNA/DNA比值下降、 总蛋白含量的升高, 以及24 kDa蛋白的存在是草地螟幼虫滞育的主要生理特征。     

光周期对淡色库蚊滞育越冬影响的观察

本文观察了光周期对淡色库蚊Culex pipiens PallensCoq.滞育越冬的影响,发现短日照导致雌蚊滞育越冬:1.卵巢滞育;卵巢平均长0.75毫米,第一卵泡平均直径0.04毫米(长日照卵巢发育,平均长1.23毫米,第一卵泡平均直径0.09毫米)。2.胃紧缩;圆柱形,无皱壁,最大横径平均为0.41毫米(长日照胃发育,有皱壁,平均最大横径0.78毫米)。3.拒绝吸血;吸血率仅为1.18%,唯一吸血的雌蚊吸血量仅为正常的1/4(长日照吸血率在80%以上)。4.积聚脂肪;含有中量和大量的占80%左右,(长日照脂肪含量少,微和少量的占80%以上)。5.寿命长可越冬;45天后有63%存活,10°—3℃温度下,越冬3个月存活28%,4个月后尚有10%,(长日照45天的全部死亡)。 对淡色库蚊光周期敏感虫期的观察,发现1至2龄幼虫对光周期不起反应。4龄幼虫、蛹和成蚊同时处理反应完全。羽化当天的雌蚊开始用短日照处理,仍可导致部分雌蚊产生滞育。胃和卵巢已发育和吸血产卵后的雌蚊不能再受短日照影响而滞育。从而说明淡色库蚊滞育越冬者均为新蚊,因此杀灭秋天蚊幼制止越冬蚊的发生是可取的。 对淡色库蚊还进行了光周期临界时间的观察,发现上海地区日照缩短到寒露后,就有大量拒绝吸血的滞育蚊出现。因此上海地区晚秋杀灭末一代蚊幼防制越冬蚊发生的工作,应在10月上旬开始进行。     

杉木雌配子体与后胚发育过程中核酸、蛋白质和类脂的消长

在杉木胚胎分化期至成熟期,每个雌配子体总核酸和DNA,RNA含量在初期增加,后期则随着胚的分化发育逐渐下降,而蛋白质和类脂则一直上升。每胚总核酸、DNA,RNA则相应增加,而蛋白质、类脂的含量和干重亦逐渐增加。在胚分化早期RNA的迅速合成与细胞的分化及器官形成有关。但以胚干重为单位的DNA、RNA含量却随着胚的发育而有所减少;蛋白质含量先增加,至成熟后才下降。授粉前的胚珠,以及雌配子体、胚中都发现有凝集素存在。     

淡色库蚊生殖滞育的神经内分泌调节

刚羽化的淡色库蚊(Culex pipiens pallens)去首后,其第I卵泡停滞在N期,不能进一步发育。 5天以上日龄滞育蚊去首后,第I卵泡约在去首后24小时即从N期开始发育。 组织切片发现,滞育蚊咽侧体(CA)体积小,形态瘦长,略呈圆锥形,胞核着色深,排列紧密,胞质少,似处于失活状态。 滞育蚊卵巢转种到发育蚊体内,其卵泡可以发育,而转种到滞育蚊体内则不能发育。类保幼激素(JHA,ZR515)及从发育蚊血淋巴液中提取的粗制保幼激素都能使滞育蚊的卵泡发育。     

小麦胚胎发育过程中蛋白质、核酸的动态变化

小麦每胚总核酸、RNA 和每细胞 RNA 含量均随胚的发育而增加,直到开花后21天达到高峰。每胚蛋白质和每细胞蛋白质含量也相应增加,但每胚蛋白质含量的增加持续到开花后24天。每毫克胚干重为单位的 RNA 含量在胚发育早期有下降,在后期有增加,每毫克胚干重的蛋白质含量也相应变化。每胚 DNA 含量在胚发育早期有增加,但之后即相对稳定。作者对 RNA 含量的变化与细胞蛋白质的合成和胚胎发育的关系进行了讨论。     

高等植物胚胎的发育生物学研究——Ⅵ.粳稻胚分化发育期间一些大分子物质的动态

鉴测了粳稻胚的发育进程及不同分化发育时期中DNA、RNA、蛋白质、淀粉含量和鲜重、干重、细胞数的变化。 开花后6～13天(胚分化第一到第四叶原基期间)胚细胞数增加时,DNA、RNA含量迅速上升。此后细胞数和DNA、RNA含量都趋于稳定,但RNA在18～25天再次增长。每胚蛋白质和干重基本上随RNA含量相应地变化。 每毫克胚于重的核酸和蛋白质含量在13天出现明显的转折。平均每细胞的DNA含量在整个发育期保持稳定,RNA第一阶段的增长只持续到分化完成的前夕,而蛋白质在25天以前一直增加。 胚内淀粉的累积在整个胚形成期呈现三段斜率不同的直线。以单位干重表示时则在8天左右和21天出现两个高峰,先于RNA和蛋白质两次积累的高峰。 在大分子物质的变化与胚胎发育进程相互关系并与籼稻比较的基础上,将稻胚发育划分为原胚期、分化期、成熟期和休止期。     

淡色库蚊生殖滞育的神经内分泌调节

刚羽化的淡色库蚊(Culex pipiens pallens)去首后,其第I卵泡停滞在N期,不能进一步发育。 5天以上日龄滞育蚊去首后,第I卵泡约在去首后24小时即从N期开始发育。 组织切片发现,滞育蚊咽侧体(CA)体积小,形态瘦长,略呈圆锥形,胞核着色深,排列紧密,胞质少,似处于失活状态。 滞育蚊卵巢转种到发育蚊体内,其卵泡可以发育,而转种到滞育蚊体内则不能发育。类保幼激素(JHA,ZR515)及从发育蚊血淋巴液中提取的粗制保幼激素都能使滞育蚊的卵泡发育。     

Changes in dry weight, protein, and nucleic acid content during diapause and normal development of the blowfly, Lucilia sericata

Dry weight (D.W.), protein, RNA, and DNA have been determined in the blowfly, Lucilia sericata, throughout all stages of normal development in long and short photoperiod regimes and during larval diapause. During normal development protein/D.W. levels fluctuate markedly during the larval and puparial stages, increased levels being correlated with the synthesis of new cuticle, etc. prior to ecdysis and the histogenesis of adult tissues prior to emergence. Protein levels remain relatively high and constant during adult life to senescence. RNA/D.W. levels are highest in first instar larvae but decline rapidly during larval development until just before puparium formation. Sharp increases are found prior to pupation and then again prior to adult emergence. In the adult stage, the levels decline steadily throughout the life span. DNA/D.W. levels are very low in the egg but rach their highest levels in early first instar larvae. They then decline during larval development, with small increases being found prior to puparium formation and adult emergence. Adult levels remain relatively constant throughout the life span. The ratio has extremely high values in the egg, indicating the high degree of synthetic activity that takes place during embryogenesis. There is a steady decline in values during adult life to senescence in both sexes, suggesting that physiological ageing in L. sericata is accompanied by a decrease in protein synthesis potential.During larval diapause all parameters, with the exception of the ratio, are maintained at low and constant levels, reflecting the fact that diapause is a period when synthetic and mitotic activity are minimal. The great variations in levels, however, indicate that individuals within a group of larvae can terminate diapause spontaneously at 24°C and return to the normal processes of morphogenesis.     

Energy metabolism during diapause in Culex pipiens mosquitoes

Diapause in overwintering adult female Culex pipiens mosquitoes plays an important role in the transmission of West Nile and other encephalitis-inducing flaviviruses. To investigate the dynamic metabolic processes that control Cx. pipiens diapause, we used radioactive tracer techniques with [¹⁴C]-glucose to investigate the metabolic fate and flux of glucose in adult mosquitoes reared under diapause (18 °C, short day) and non-diapause (27 °C, long day) conditions. We found that by 72 h post-¹⁴C-labeling of 1-day-old mosquitoes, the diapause-destined mosquitoes had converted 46% more ¹⁴C-labled glucose into ¹⁴C-labled lipid than mosquitoes reared under non-diapausing conditions. When 5-day-old mosquitoes were fed [¹⁴C]-glucose, and then switched to water only, the non-diapausing mosquitoes oxidized nearly three times more ¹⁴C-labled glycogen and lipid by day 7 than diapausing-mosquitoes. This increased energy expenditure in non-diapausing mosquitoes is most likely due to temperature- and light-dependent increases in the basal metabolic rate. Amongst the diapausing-mosquitoes we analyzed over a subsequent 7-week period, we found that the amount of ¹⁴C-labeled glycogen decreased steadily for the first month of diapause, whereas, ¹⁴C-labeled-lipid levels were not significantly decreased until after day 35 of diapause, indicating that flux through glycogenolysis is higher than lipolysis during the first month of diapause. Lastly, our analysis revealed that 38% of the initial ¹⁴C-labled lipid that was synthesized during the adult pre-diapause phase was still present following the first gonotrophic cycle. About 33% of this remaining ¹⁴C-labeled lipid was localized to the newly developed eggs, suggesting that lipid sparing processes during a minimal 7-week long diapause may enhance egg production.     

Feeding,reproductive and locomotor activities in diapausing and non-diapausing adults ofDrosophila

Feeding, reproductive and locomotor activities of fourDrosophila species were studied under short and long daylengths at 15°C. A short daylength induced firm reproductive diapause in experimental strains ofD. subauraria andD. triauraria from northern Japan, but very shallow diapause in those ofD. lutescens andD. rufa from southern Japan. A subtropical strain ofD. triauraria had no diapause. The influence of diapause on feeding activity was detected only in aged (> 12 day old) females; that is, the feeding activity was lower in diapausing females than in non-diapausing ones. Females that do not produce eggs would not require so much energy. On the other hand, young adults of the study species exhibited a high feeding activity and rapidly increased bodyweight irrespective of sex and the diapause state. They would need nutrition to build up their adult body. In males, the feeding activity decreased with age irrespective of the diapause state. Males would not require so much energy for reproductive activity. Diapausing males became heavier than non-diapausing males, perhaps because they accumulated triacylglycerols in fat bodies. However, female bodyweight did not differ by the diapause state, perhaps because diapausing females accumulated triacylglycerols and reproducing females had eggs in their ovaries. InD. triauraria, diapausing individuals exhibited somewhat lower locomotor activity than non-diapausing ones.     

Cold tolerance in diapausing and non-diapausing stages of the flesh fly, Sarcophaga crassipalpis

ABSTRACT. Supercooling points (SCP) and low temperature tolerance were determined for larval, pupal and adult stages of Sarcophaga crassipalpis Macquart (Diptera: Sarcophagidae). No stage tolerates tissue-freezing. Ontogenetic changes in SCP profiles are similar for comparable developmental stages of diapause and non-diapause groups. Feeding larvae have SCPs near -7°C which decrease to -11°C in the postfeeding wandering phase of the final larval instar. The lowest SCPs are recorded for pupae at -23°C. The capacity to survive at -17°C varies with age of the diapausing pupae: 10-day-old pupae are less cold tolerant than pupae that have been in diapause for 45–80 days. Although the SCP of non-diapausing pupae is as low as in diapausing pupae, non-diapausing pupae are extremely sensitive to low temperature exposure and do not survive to adult eclosion when exposed to -17°C for as little as 20 min. The use of hexane to break pupal diapause has no effect on SCPs or low temperature tolerance.     

Over-wintering stage polymorphism of a bruchine beetle: geographical variation in optimal diapause strategy

Abstract.  1. Most temperate insects undergo diapause at a specific developmental stage to overcome severe winters. The bruchine beetle Bruchidius dorsalis in a warmer region in Japan, however, has diverse over-wintering stages – non-diapausing larvae, diapausing larvae, and diapausing adults, whereas in a cooler region, it over-winters only as the final instar larva or adult in diapause.
2. The geographical pattern of over-wintering stages in 12 populations was investigated over a wide range along the mainland of Japan. It revealed that a distinct geographical pattern of over-wintering stages exists in relation to temperature conditions. In regions with warmer climates, the proportion of non-diapausing larvae increased and B. dorsalis had a more complex over-wintering stage structure.
3. Life cycles were also compared between two areas of Japan by field experiments. In the cooler area, the first generation over-wintered in the diapausing larval or adult stage. Conversely, in the warmer area, diapause was induced later and some of the first-generation adults produced second-generation offspring before over-wintering.
4. Based on the geographical cline of climates and the differences in cold hardiness among stages, we can demonstrate that the over-wintering stage variation among and within populations results from an adaptive timing of diapause induction in each region, because the late larval or adult diapauses protect pupae or eggs – which unlike other stages are not cold hardy – from being produced late in the season.     

Drosophila americana Diapausing Females Show Features Typical of Young Flies

Diapause is a period of arrested development which is controlled physiologically, preprogrammed environmentally and characterized by metabolic depression that can occur during any stage of insect development. Nevertheless, in the genus Drosophila, diapause is almost always associated with the cessation of ovarian development and reproductive activity in adult females. In this work, we show that, in D. americana (a temperate species of the virilis group), diapause is a genetically determined delay in ovarian development that is triggered by temperature and/or photoperiod. Moreover, we show that in this species diapause incidence increases with latitude, ranging from 13% in the southernmost to 91% in the northernmost range of the distribution. When exposed to diapause inducing conditions, both diapausing and non-diapausing females show a 10% increase in lifespan, that is further increased by 18.6% in diapausing females, although senescence is far from being negligible. ActinD1 expression levels suggest that diapausing females are biologically much younger than their chronological age, and that the fly as a whole, rather than the ovarian development alone, which is phenotypically more evident, is delayed by diapause. Therefore, diapause candidate genes that show expression levels that are compatible with flies younger than their chronological age may not necessarily play a role in reproductive diapause and in adaptation to seasonally varying environmental conditions.     

Relationship between brain trehalase activity and trehalosema during direct and diapausing development in Pieris brassicae

• 1.1. Brain trehalase specific activity and trehalosemia were measured during the end of the developmental life cycle in non-diapausing and diapausing insects.
• 2.2. During non-diapausing development, trehalosemia reached maximum values at the beginning of pupal life. Then a constant decrease was observed up to the end of adult life.
• 3.3. The specific activity of brain trehalase was maximum when the insects were in active feeding periods, minimum activity appearing during moulting phases.
• 4.4. During diapausing development, trehalosemia was very high at the beginning of pupal life, particularly when insects were exposed to wintering conditions.
• 5.5. When diapause was broken, trehalosemia fell, announcing adult emergence.
• 6.6. Brain trehalase activity showed the same qualitative variations as in non-diapausing larvae, but with rather lower values.
• 7.7. During pupal life, brain trehalase activity decreased markedly during the long period necessary to obtain diapause breakdown.
• 8.8. Wintering conditions allow a progressive increase of brain trehalase activity, which preceded the fall of trehalosemia.