26-hydroxyecdysone: new insect molting hormone from the egg of the tobacco hornworm

Five kilograms of tobacco hornworm eggs (48 to 64 hours old) afforded 26.5 milligrams of a new crystalline insect molting hormone identified as 26-hydroxyecdysone. The three known insect ecdysones-alpha-ecdysone, 20-hydroxyecdysone, and 20,26-dihydroxyecdysone-were also present but in much smaller quantities. The new hormone is the predominant molting hormone in the hornworm during this stage of embryonic development. These results takent in context with the current knowledge of the chemistry and biochemistry of the molting hormones during postembryonic development in the hornworm indicate quantitative and qualitative differences in the biosynthetic-mnetabolic pathways as well as in the ecdysones in different developmental stages of this insect.     

Ecdysone analog: conversion to alpha ecdysone and 20-hydroxyecdysone by an insect

The tritium-labeled synthetic ecdysone analog Delta(7)-5beta-cholestene-2beta,-3beta,14alpha-triol-6-one terminated diapause when injected into diapausing tobacco hornworm pupae and was converted into tritium-labeled alpha-ecdysone and tritium-labeled 20-hydroxyecdysone. About half of the crystalline alpha-ecdysone and 20-hydroxyecdysone isolated from the tobacco hornworms 7(1/2) to 8(1/2) days after injection was derived from endogenous steroid precursors and half from the transformation of the synthetic ecdysone analog.     

竹醋铜制剂对绿藻及烟苗生长的影响

为探明烤烟漂浮育苗中防治绿藻的有效方法,采用浸泡和喷施法研究不同浓度竹醋铜制剂对绿藻及烟苗生长的影响。结果表明:各浓度竹醋铜制剂对绿藻生长均具有较强的抑制作用,且与硫酸铜相比具有一定增效作用。喷施竹醋铜制剂200倍液能明显促进烟苗生长,其叶鲜重较清水对照增加15.80%,差异显著;而喷施50倍液不利于烟苗生长。建议在烤烟漂浮育苗时喷施竹醋铜制剂200倍液,可在不同程度上促进烟苗生长并减少绿藻滋生。     

Cellular Response to Ecdysterone in vitro

Organ cultures of hindgut from diapausing tobacco hornworm pupae, Manduca sexta (Johannson), produce an abundance of migrant cells around the original explant. With time-lapse cinematography, these cells were seen to move slowly and tended to aggregate. The addition of ecdysterone (beta-ecdysone) to these cultures stimulated a large increase in individual cell movements and the eventual disruption of cell sheets.     

JH Zero: New Naturally Occurring Insect Juvenile Hormone from Developing Embryos of the Tobacco Hornworm

A new insect juvenile hormone was isolated from developing embryos of the tobacco hornworm moth, Manduca sexta. The new hormone was found with juvenile hormone I and is a 1-carbon homolog of this substance. The assigned structure is methyl (2E,6E,10-cis)-10,11-epoxy-3,7-diethyl-11-methyl-2,6-tridecadienoate, which constitutes a trishomosesquiterpenoid skeleton. This is the first chemical idetification of any juvenile hormone from insect eggs.     

品种多样性对烤烟主要农艺性状及抗性的影响

[目的]分析品种多样性对烤烟生产的影响.[方法]烤烟品种K326、云烟87、云烟85和红花大金元间作,以试验当地连片种植的烤烟品种（K326）为对照.[结果]品种多样性能有效防治体系中炭疽病、气候性斑点病,却降低了体系对赤星病、普通花叶病和烟青虫的抵抗能力.与对照相比,品种多样性使烤烟产量和产值分别提高17.81％和10.42％,但使上等烟比例降低10.36％.[结论]该研究可为以后在烟草生产上积极开发、保护和利用生物多样性以提高烟草产、质量提供理论依据.     

蜜蜂(Apis mellifera)腺苷酸转移载体基因cDNA的电子克隆

 以果蝇腺苷酸转移载体基因cDNA序列为信息探针,对蜜蜂EST数据库进行同源检索筛选,克隆了蜜蜂腺苷酸转移载体基因(Am　ant)的cDNA序列(GenBank登记号为AY332626),该基因全长1 251bp。经RT-PCR克隆、序列分析验证,结果表明与电子克隆序列完全一致;该基因具有完整的开放阅读框架(ORF),编码蛋白为300个氨基酸,通过对人、果蝇、家蚕及烟草天蛾的腺苷酸转移载体蛋白序列比较,发现该基因具有高度的保守性;说明根据物种间同源基因序列,进行跨物种EST数据库的同源检索筛选、拼接,是基因克     

N-beta-Alanyldopamine: Major Role in Insect Cuticle Tanning

N-beta-Alanyldopamine is the major tyrosine metabolite in the hemolymph and cuticle during pupal tanning in the tobacco hornworm, Manduca sexta L. Its concentration in hemolymph increases over 800-fold above larval levels by the start of tanning and decreases as the pupal cuticle darkens and hardens. It is a major catechol in species representing several insect orders and is the preferred substrate for pupal cuticular o-diphenol oxidase. In insects, N-beta-alanyldopamine appears to be the main precursor for tanning chemicals at certain developmental stages.     

Insect prothoracicotropic hormone: evidence for two molecular forms

In an insect, the tobacco hornworm Manduca sexta, the cerebral neuropeptide prothoracicotropic hormone (PTTH), the primary effector of postembryonic development, exists as two molecular forms. These two PTTH's elicit characteristic in vitro dose responses of activation of prothoracic glands from different developmental stages, an indication that during development the glands change in their sensitivity to the neurohormones. Both PTTH's are active in a specific in situ bioassay. Since they may be released in situ at stage-specific times to evoke distinctly different developmental responses, the PTTH neuroendocrine axis appears to be an effective system for determining the functions of molecular forms of a neurohormone in the regulation of growth and development.     

RH 5849, a Nonsteroidal Ecdysone Agonist: Effects on Larval Lepidoptera

The ecdysone agonist RH 5849 (1,2-dibenzoyl-1-tert-butylhydrazine) causes the premature initiation of molting at all stages of larval development of the tobacco hornworm, Manduca sexta. This phenomenon occurs without an increase in the endogenous ecdysone (20-hydroxyecdysone) titers. RH 5849 likewise provokes the initiation of molting in larval abdomens in the absence of a source of endogenous hormone. Although substantially less active than 20-hydroxyecdysone in vitro, RH 5849 was 30 to >670 times as active as the authentic molting hormone in bioassays with isolated larval abdomens or intact hornworms. This reversal in potency can be attributed to the superior transport properties and metabolic stability of RH 5849 relative to 20-hydroxyecdysone. Thus RH 5849 and its analogs are relatively persistent ecdysone agonists that halt feeding in larval lepidoptera by forcing an ultimately lethal, developmentally premature molt.     

竹醋铜制剂对烟株生长发育的影响

为筛选绿色药肥制剂应用于烟叶生产,采用随机区组试验研究竹醋铜制剂不同稀释浓度处理对烤烟农艺性状、干物质积累、叶绿素含量及净光合速率等指标的影响。结果表明:大田喷施竹醋铜制剂200~400倍液可明显改善烟株生长发育,低于100倍液则产生抑制效果。其中,400倍液能够显著提高烟叶的净光合速率,促进叶片干物质积累,较对照(清水)分别提高62.11%和18.33%;同时其株高和茎围分别比对照增加26.10%和19.01%,但是对叶片的叶绿素含量影响不明显。     

Juvenile hormone is required to couple imaginal disc formation with nutrition in insects

In starved larvae of the tobacco hornworm moth Manduca sexta, larval and imaginal tissues stop growing, the former because they lack nutrient-dependent signals but the latter because of suppression by juvenile hormone. Without juvenile hormone, imaginal discs form and grow despite severe starvation. This hormone inhibits the intrinsic signaling needed for disc morphogenesis and does so independently of ecdysteroid action. Starvation and juvenile hormone treatments allowed the separation of intrinsic and nutrient-dependent aspects of disc growth and showed that both aspects must occur during the early phases of disc morphogenesis to ensure normal growth leading to typical-sized adults.     

打顶后喷施不同生物制剂对烤烟品质的影响

为研究常用生物制剂对烟叶品质提升的影响,探索适宜施用方法促进优质烟叶生产,在大田条件下,研究了打顶后喷施6种不同生物制剂对烤后烟叶理化性状及致香物质含量的影响。结果表明：不同生物制剂对改善烟叶品质均有一定作用,赤霉素（GA3）能显著提高烟叶的叶长、叶宽、单叶重、叶质重和抗张性,有效的降低烟碱含量,提升钾、总氮含量,改善烟叶内在化学成分的协调性,并提高致香物质含量,整体效果最优,生长素次之。     

几种植物提取液对感染TMV烟草叶片核酸及类黄酮含量的影响

[目的]研究几种提取液对烟草花叶病毒（TMV）的抑制作用及其防治效果,为植物源抗病毒类生物农药的研制提供依据。[方法]以K326为试验材料,采用常规摩擦接种,感染病毒后,喷施白花蛇舌草、莲提取液及由20种植物加工而成的植物源抗病毒制剂（配伍制剂）,于接种后第5、10、15、20天测定核酸及类黄酮含量,分析几种提取液对TMV的抑制作用。[结果]喷施植物提取液后,烟株体内的DNA含量升高,均高于阳性对照,说明烟株细胞恢复了正常的合成能力;而RNA含量比阳性对照低,说明烟株体内的TMV含量降低,喷施植物提取液能够恢复植物细胞的正常功能;类黄酮含量增加。植物提取液抑制了TMV在烟株体内的复制能力,其中以配伍制剂的效果最好。[结论]喷施植物提取液能够恢复植物细胞的正常功能,以喷施配伍制剂的效果最好。     

The cellular and physiological mechanism of wing-body scaling in Manduca sexta

In animals, appendages develop in proportion to overall body size; when individual size varies, appendages covary proportionally. In insects with complete metamorphosis, adult appendages develop from precursor tissues called imaginal disks that grow after somatic growth has ceased. It is unclear, however, how the growth of these appendages is matched to the already established body size. We studied the pattern of cell division in the tobacco hornworm Manduca sexta and found that both the rate of cell division and the duration of growth of the wing imaginal disks depend on the size of the body in which they develop. Moreover, we found that both of these processes are controlled by the level and duration of secretion of the steroid hormone ecdysone. Thus, proportional growth is under hormonal control and indirectly regulated by the central nervous system.     

施用不同有机肥对烤烟产质量的影响研究

该文采用田间试验示范和室内分析的方法,分别研究了施用微生物菌剂和有机肥对烤烟产质量的影响,为微生物菌剂和竹炭生物有机肥在烤烟生产中的应用提供理论依据。结果表明,施用微生物菌剂对烤烟生长发育、产质量形成及内在化学成分的协调性具有明显影响,提高了中上等烟的比率,增加了产值,可以在以后烤烟生产中加大推广面积;施用竹炭生物有机肥,烟叶产量相对下降(试验配方氮肥不足是主要原因),竹炭生物有机肥能够对烟叶成熟落后有较好的促进作用,烟叶品质有轻微提高,在今后的烤烟生产中应继续改进施肥配方比例,并加以大面积推广。     

绿针假单胞菌PL9菌株对烟草疫霉的拮抗作用研究

利用离体拮抗试验和烟草幼苗生物测定法研究了棉花根圈细菌绿针假单胞菌（Pseudomonas choloraphis)PL9菌株对烟草黑胫病原菌烟草疫霉（Phytophthora parasitica var.nicotianae)的拮抗作用，该菌株对烟草疫霉菌丝体有很强的抑制作用，并且可以完全抑制烟草疫霉游动孢子对烟草幼苗的侵染，其液体培养物浓缩过滤液也有相同的报制作用，拮抗作用机理研究结果表明，其拮抗作用可能与PL9菌株分泌的抗生素类物质有关。为了解PL9菌株在烟草根圈的定殖情况，采用全套发光酶基因（luxCDABE)标记的菌株PL9L进行跟 踪，结果表明该菌株可以在烟草根圈成功定殖。     

人工释放天敌防治烟田害虫的研究

采用人工释放赤眼蜂和瓢虫对烟地主要害虫进行生物防治,对生物与化学药剂田间防治效果进行调查、记载并对防治效果进行了比较。结果,生物防治与化学药剂田间防治效果相当,但有利于生态环境的保护和生产无公害农产品,值得大面积推广使用。     

烟青虫生物防治药剂的筛选

为筛选出防治烟青虫的生物防治剂供贵州有机烟叶生产上使用,采用田间比较鉴定、室内检测分析等方法,从烟株的抗虫性、初烤烟叶外观和内在品质等方面研究了5种烟青虫生物防治剂的防治效果及其对烟叶生产的影响。结果表明:参试的5种生物药剂中,0.3%苦参碱水剂和苏云金杆菌对烟青虫的防效显著,其药后1d、3d、7d对烟青虫的防效分别是72.09%、93.55%、100%和44.18%、90.32%、100%,药效的发挥较接近化学对照药剂2.5%高效氯氟氰菊酯乳油1 500倍液的防治效果,且对烟叶的外观和内在品质无负面影响,是当前贵州有机烟叶生产中较为理想的烟青虫生物防治剂。     

Aromatic cross-links in insect cuticle: detection by solid-state 13C and 15N NMR

Cross-polarization magic-angle-spinning nuclear magnetic resonance spectroscopy has been used to determine insect cuticle composition and cross-link structure during sclerotization or tanning. Unsclerotized cuticle from newly ecdysed pupae of the tobacco hornworm, Manduca sexta L., had a high protein content with lesser amounts of lipid and chitin. Concentrations of chitin, protein, and catechol increased substantially as dehydration and sclerotization progressed. Analysis of intact cuticle specifically labeled with carbon-13 and nitrogen-15 revealed direct covalent linkages between ring nitrogens of protein histidyl residues and ring carbons derived from the catecholamine dopamine. This carbon-nitrogen adduct was present in chitin isolated from cuticle by alkaline extraction and is probably bound covalently to chitin. These data support the hypothesis that the stiffening of insect cuticle during sclerotization results primarily from the deposition of protein and chitin polymers and their crosslinking by quinonoid derivatives of catecholamines.