Inhibition of ecdysteroid production in nymphs of Rhodnius prolixus treated with ethoxyprecocene II

Rhodnius prolixus nymphs fed 7-ethoxy-6-methoxy-2,2-dimethylchromene (ethoxyprecocene II, EPII) show a variety of responses, including precocious molting to diminutive adults, severe retardation of molting, or a condition of permanent ecdysial stasis. The latter two conditions are reversible by subsequent treatment with 20-hydroxyecdysone. Ecdysteroid titers in the hemolymph of individual insects, determined by radioimmunoassay (RIA), show that the ecdysteroid cycle in nymphs undergoing precocious metamorphosis is similar to that of untreated fifth stage nymphs during normal imaginal molting. Nymphs in ecdysial stasis, following EPII treatment, were found to have very low ecdysteroid titers. Analysis of ecdysteroid synthesis by the prothoracic glands (PG), cultured in vitro, showed that: 1) only traces of ecdysteroid were detectable in PG from nymphs treated in vivo with EPII; 2) the PG from untreated nymphs incubated in culture medium with EPII possessed significantly lower ecdysteroid synthesis compared with controls. These studies sought to determine if the inhibition of ecdysteroid biosynthesis observed in Rhodnius, following exposure to EPII in vivo and in vitro, is due to a direct action on the PG or result as an indirect effect perhaps mediated by the neuroendocrine system.     

Penetration of the cuticular layers of elaterid larvae (Coleoptera) by the fungus Metarrhizium anisopliae, and notes on a bacterial invasion

The penetrant hyphae of Metarrhizium anisopliae in the exuvial cuticle of a molting wireworm can form secondary appressoria on the developing new cuticle. From these a new penetrant fungal apparatus can develop through the new cuticle toward the body cavity. The penetrant fungal apparatus in the ecdysial space of the host does not appear to be affected by the histolytic enzymes in the wireworm molting fluid. A mucoidlike substance that envelopes the fungus in the ecdysial space may be, in part, the protective mechanism involved. Bacteria from the soil often invade the ecdysial space of molting wireworms that have difficulty in shedding their exuvia. Pseudomonas aeruginosa can histolyze the proteinaceous exocuticle of the exuvium, the ecdysial membrane, and the dense inner epicuticle of the new cuticle, but not the epicuticle of the exuvium, when it invades the ecdysial space of a molting wireworm.     

Precocious metamorphosis and wing formation in the pea aphid,Acyrthosiphon pisum,induced by precocene analogue 7-ethoxy-6-methoxy-2,2-dimethylchromene

Maternal treatment with 5 μg of the precocene analogue 7-ethoxy-6-methoxy-2,2-dimethylchromene influenced offspring development in the pea aphid, Acyrthosiphon pisum. Under conditions favoring the production of apterous offspring, virginoparous aphids produced a significant proportion of alates and precocious adultoids; the precocious adultoids were sterile. The effect of precocene on offspring development was temporary. Some implications of precocene treatment for aphid control are discussed.     

三丫苦的化学成分研究

采用硅胶柱层析从三丫苦的乙酸乙酯萃取物中分离得到6种化合物,经波谱分析鉴定为4,7-二甲氧基呋喃喹啉生物碱(1)、顺式-3,4,5-三羟基-6-乙酰基-7-甲氧基-2,2-二甲基色烷(2)、3-羟基-4-乙氧基-5,7-二甲氧基-6-乙酰-2,2-二甲基色烷(3)、3,5-二羟基-4-乙氧基-6-乙酰基-7-甲氧基-2,2-二甲基色烷(4)、异吴茱萸酮酚(5)和异吴茱萸酮酚甲醚(6)。所有化合物均首次从该植物的根部分离得到。     

Bioefficacy of root extracts of a medicinal plant,Withania somnifera (Dunal) against a polyphagous pest,Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae)

Oral administration of root extracts of a medicinal plant, Ashwagandha (Withania somnifera) to last instar larvae of a polyphagous pest, Spodoptera litura resulted into abnormal morphogenesis and the effects comprised mortality, delay in larval-pupal and pupal-adult ecdysis, ecdysial stasis, formation of larval-pupal and pupal-adult intermediates, reduced pupation and formation of abnormal pupae, complete suppression of normal adult emergence and formation of adultoids. These effects are similar to those produced by the administration of JHAs and may be due to interference with the normal hormonal mechanism of moulting and metamorphosis.     

三个新2,2—二甲基苯并二氢吡喃类化合物的分离与鉴定

从中药三叉苦(Evodia lepta(Spreng.)Merr.)的地上部分分离鉴定了4个化合物。通过光谱解析和结构沟通的方法确定了它们的结构。其中3个为新化合物,依次命名为leptin A(Ⅰ)、leptin B(Ⅱ)和leptin C(Ⅲ)。另外一个已知化合物为异吴茱萸酮酚(Ⅳ)。     

Molting and cuticle deposition in the subterranean trichoniscid Titanethes albus (Crustacea, Isopoda)

Terrestrial isopods are a suitable group for the study of cuticle synthesis and calcium dynamics because they molt frequently and have evolved means to store calcium during molt. Little data is currently available on molting in Synocheta and subterranean isopods. We studied the molting dynamics in the subterranean trichoniscid Titanethes albus under laboratory conditions and performed a microscopic investigation of sternal CaCO(3) deposits and the tergal epithelium during molt in this species. In accordance with its lower metabolic rate, molting in the laboratory is roughly 2-3 times less frequent in Titanethes albus than would be expected for an epigean isopod under similar conditions. Animals assumed characteristic postures following the molt of each body half and did not consume the posterior exuviae after posterior molt. The structure of sternal calcium deposits and the ultrastructural characteristics of the epidermis during cuticle formation in Titanethes albus are similar to those described in representatives of Ligiidae. During the deposition of the exocuticle, the apical plasma membrane of epidermal cells forms finger-like extensions and numerous invaginations. In the ecdysial space of individuals in late premolt we observed cellular extensions surrounded by bundles of tubules.     

Cordiachromes from Auxemma oncocalyx

Further cordiachromes, rel-10,11β-epoxy-11-ethoxy-8-hydroxy-2-methoxy-8aβ-methyl-5,6,7,8,8a,9,10aβ-octahydro-1,4-anthracendione, 6-formyl-2-methoxy-9-methyl-7,8-dihydro-1,4-phenanthrendione, rel-8,11;9,11-diepoxy-1,4-dihydroxy-2-methoxy-8aβ-methyl-5,6,7,8,8a,9,10,10aβ-octahydro-10-anthracenone, rel-9,11-epoxy-1,4,8-trihydroxy-2-methoxy-8aβ-methyl-5,6,7,8,8a,9,10,10aβ-octahydro-10-anthracenone, rel-2″-methoxy-7″-methyl-1″,4″-naphtalendione-(6″→5)-tetrahydropyran-(2-eq→O→2ax)-tetrahydropyran-(5′→6)- 2-methoxy-7-methyl-1,4-naphthalendione, together with the known, allantoin, sitosterol and 3β-O-d-glucopyranosylsitosterol, have been isolated from Auxemma oncocalyx. Their structures were determined from spectral data, including 2D NMR experiments.     

“Exolysosomes,” Enzyme-Containing Vesicles in the Ecdysial Space of Molting Crabs

Free vesicle-like bodies (VLBs) present in the ecdysial space of cuticle regions undergoing degradation during preecdysis of the Atlantic shore crabCarcinus maenashave been interpreted either as infectious organisms or as secretion structures associated with degradation of the old cuticle. Ultrastructural, cytochemical, and immunocytological investigations were performed to test these hypotheses and to see whether VLBs are peculiar to this crab species. Similar VLBs were systematically found in two other preecdysial crabs,Cancer pagurusandMacropipus puber.InCar. maenas,they originate during early premolt inside Golgi buddings and are often gathered into large vacuoles in epidermal cells. The histochemical azo-dye technique and a cerium-based cytochemical method revealed acid phosphatase activity in both the ecdysial space and the VLBs, while Feulgen's method and immunocytological labeling always failed to reveal any DNA or RNA in either the ecdysial space or the VLBs. We conclude that VLBs are not infectious organisms but “extracellular” cuticle-degrading organelles of lysosomal origin and propose to coin them “exolysosomes.”     

Growth and molting in epizoic pedunculate barnacles genus Octolasmis (Crustacea: Thecostraca: Cirripedia: Thoracica)

Scanning electron microscopy, light microscopy, and histology were used to study growth in species of the pedunculate barnacle genus Octolasmis (O. angulata, O. cor, O. californiana, O. mülleri). These species are epizoic in the gill chamber of portunid crabs and have highly reduced capitular shell plates, with large areas of general cuticle in between. The external integument grows by means of a system of narrow growth zones, one encircling the peduncle and a Y-shaped system on either side of the capitulum. Growth is by a regular series of molts, but shedding of old cuticle and production of new layers is entirely restricted to the growth zones. Just prior to ecdysis, the new cuticle lies in a highly folded fashion beneath the old cuticle that is about to be shed. At ecdysis, the old cuticle breaks along the margins of the growth zones and the resulting scars remain as a system of "ecdysial lines" along either side of the zone. Once exposed after ecdysis, the new cuticle remains as a part of the permanent external integument. The growth zones divide the externa into five cuticular areas, two on the peduncle and three on the capitulum. The calcareous shell plates (carina, paired scuta, and, when present, paired terga) all lie within the capitular regions and the ecdysial lines pass across, not around, these mineralized areas. The number, relative spacing, and topology of the ecdysial lines form a record of the growth history of the specimen. These and other growth patterns demonstrate that size increase is due to the formation of new cuticle by molting in the growth zones, while expansion of the shell plates by mineralization follows only after production of the new cuticle. Thus, although specialized, growth in Octolasmis still complies with the general crustacean model, complicated only by the mineralization of parts of the capitular cuticle into shell plates. The results are compared with the very scarce information on molting in other barnacles. We argue that at least the circular peduncular growth zone is omnipresent in the Cirripedia Thoracica.     

Heterochrony in cotton bollworm, Earias vitella (Fb) following ethoxyprecocene administration

Administration of a synthetic precocene analogue, 7-ethoxy-6-methoxy-2,2-dimethyl chromene to fourth and last instar larvae of E. vitella results into heterochrony, viz. prothetely and metathetely. These disturbances are due to interference with the endocrine system and application of juvenile hormone to treated larvae abolishes the effect of ethoxyprecocene.     

2,3-dihydrojaborosalactone A,a withanolide from Acnistus breviflorus

From Acnistus breviflorus the new 27-hydroxy-5β,6β-epoxy-1-oxo-(22R)-witha-24-enolide (2,3-dihydrojaborosalactone A) as well as seven known withanolides, withaferin A, 2,3-dihydrowithaferin A, 6α-chloro-5β-hydroxywithaferin A, 5,6-deoxywithaferin A, jaborosalactone A, jaborosalactone D and jaborosalactone E were isolated and characterized by means of spectroscopic (¹H NMR, ¹³ C NMR and mass spectral) methods. Depending on the extraction solvent (methanol or ethanol), a known artifact (3β-methoxy-2,3-dihydrowithaferin A) and the new 5α-methoxy-4,5-dihydrojaborosalactone B and 5α-ethoxy-4,5-dihydrojaborosalactone B were also isolated and characterized.     

Triterpenes and lignans from the leaves of Styrax tonkinensis

Two triterpenes (1 and 2) and eight lignans (3–10) were isolated from the ethyl acetate-soluble fraction of the leaves of Styrax tonkinensis (Pierre) Craib ex Hartw (Styracaceae). Their structures were established as ursolic acid (1), pomolic acid (2), 3,3′-bis(3,4-dihydro-6-methoxy-2H-1-benzopyran) (3), rac-(8α,8′β)-4,4′-dihydroxy-3,3′-dimethoxylignan-9,9′-diyldiacetate (4), (-)-secoisolariciresinol (5), (+)-pinoresinol (6), 4,4′-dihydroxy-3,3′-dimethoxy-9-ethoxy-9,9′-epoxylignan (7), (2S,3R, 4R)-4-[1-ethoxy-1-(4-hydroxy-3-methoxy)phenyl]methyl-2-(4-hydroxy-3-methoxy)phenyl-3-hydroxymethyl-tetrahydrofuran (8), (-)-neo-olivil-(9-O-9″)-seco-isolariciresinol (9) and isolariciresinol (10) based on MS, ¹H-and ¹³C-NMR spectral data. All these compounds (1–10) were firstly isolated from this plant, and compounds 2–5 and 7–9 were reported from the Styrax genus for the first time. Furthermore, the chemotaxonomic significance of the isolated compounds was discussed.     

Histological and ultrastructural studies of Beauveria bassiana infection in Leptinotarsa decemlineta larvae during ecdysis

Studies of Leptinotarsa decemlineata larvae infected by Beauveria bassiana during ecdysis have enabled us to define the modes of fungal penetration employed to enter the ecdysial cuticle. We have observed the mechanically active passage of the penetrant hyphae and have followed the growth of the filaments and blastospore formation in the molting fluid. The attack of the new integument and its consequent alteration and the entry into the body cavity have also been studied. The infection develops rapidly in some of the larvae which die in premolt, while others are able to molt. Conditions rendered abnormal due to the presence of the fungus cause integumentary injuries which serve as an important factor in pathogenesis since they enhance the entry of fungal elements and bacteria thereby inducing septicemia. Contaminated larvae are able to molt, showing no signs of injury or disease, and survive for a long time, until the fungus finally invades the organism and causes death. This postponement of mortality shows that molting and hemocytic reactions are, to a certain extent, an effective defense mechanism. These last observations can be useful in the understanding of pathological processes associated with a hidden phase of fungal infection.     

Biodegradation of VOCs from printing press air by an on-site pilot plant bioscrubber and laboratory scale continuous yeast cultures

The volatile organic compound composition (VOCs) of printing press air wasfound to contain mostly ethanol, but also ethyl acetate, 1-propanol, 2-propanol,1-methoxy-2-propanol and 3-ethoxy-1-propanol. A pilot plant bioscrubber inoculatedwith a mixed microbial population was constructed on-site. The bioscrubber wasable to treat the polluted gas efficiently. It, however, suffered from strong wall growthand blockages in the column. The efficiencies of the pilot plant and a bioreactor iscompared. The yeasts Candida guilliermondii and Saccharomyces cerevisiae known to tolerate ethanol were selected instead of mixed population to avoid the wall growth and blockages in the bioreactor. The removal of the VOCs both individually and as a complex mixture was tested in a microcultivation system and in continuous chemostat cultures with and without cell recycling. The Candida yeast could use all the compounds as a carbon source while growth of S. cerevisiae was markedly slower on the methoxylated and ethoxylated propanols. Best total removal of the VOCs was 99% and achieved by C. guilliermondii. The only compound that was not totally removable in the chemostat experiment with C. guilliermondii was 1-methoxy-2-propanol. In laboratory scale the total and volumetric removal of VOCs by C. guilliermondii was more efficient compared to the pilot plant encouraging to scale up and applying the yeast bioreactor to real field conditions.     

20-羟基蜕皮甾酮处理后舞毒蛾外部形态和幼虫体壁超微结构的变化

为了探明20-羟基蜕皮甾酮对昆虫蜕皮过程中体壁的表皮层、 皮细胞及其细胞器的具体影响过程, 本研究利用透射电镜技术研究了20-羟基蜕皮甾酮对舞毒蛾Lymantria dispar （Linnaeus）5龄幼虫体壁超微结构的变化。结果表明, 用高浓度20-羟基蜕皮甾酮溶液浸过的白桦叶片饲喂幼虫, 处理6 h, 摄入约400 μg 20-羟基蜕皮甾酮后, 幼虫停止取食; 处理12 h时表皮细胞顶膜上的微绒毛减少, 在皮细胞与旧表皮之间形成蜕皮间隙, 旧头壳从幼虫头部脱离; 处理24 h时蜕皮间隙继续增大, 旧表皮与皮细胞进一步分离, 新表皮质层开始形成; 处理36 h时皮细胞顶膜形成较短的微绒毛, 胞质区域出现数量较多的电子疏松泡, 新表皮由上表皮、 外表皮及8层左右内表皮片层组成; 处理48 h时顶膜与内表皮界限模糊, 内表皮继续合成至16层左右; 72 h时细胞内出现大面积电子疏松泡, 内表皮合成至20层左右。 处理96 h时, 与对照组相比, 皮细胞细胞器较少, 核仁周围出现小部分空白区域, 胞质区域内含物减少; 虫体发黑缩小, 即将死亡; 内表皮层数仍旧保持20层左右。对照组幼虫6-96 h虫体活跃, 正常取食, 外部观察及透射电镜结果均未显现蜕皮现象; 表皮层由上表皮、 外表皮及内表皮组成; 皮细胞顶膜微绒毛密度高; 表皮细胞分泌活动旺盛, 胞质区域细胞界限明显, 内含物丰富; 细胞器典型而且活跃; 内表皮片层随时间不断增加至50层左右。结果提示, 外源20-羟基蜕皮甾酮能够导致舞毒蛾5龄幼虫的致死性蜕皮。     

Methyl farnesoate and juvenile hormone III in normal and precocene treated embryos of the ovoviviparous cockroach Nauphoeta cinerea

Summary

Titers of juvenile hormone III and methyl farnesoate, its unepoxidized precursor, were measured throughout embryonic development using a gas-chromatographic method and it was revealed that both substances are undetectable before dorsal closure. Thereafter they both reach similarly high concentrations (800 ng/g) until a few days before hatching, when their titers begin to decrease. Application of the precocene analogue, 7-ethoxy-6-methoxy-2,2-dimethyl-chromene, to egg-cases at dorsal closure results in very low or undetectable titers of juvenile hormone III, depending on the dose applied, whereas methyl farnesoate is seen to reach high levels similar to those seen in the controls. The severe developmental disturbances observed suggest that juvenile hormone III is very important for normal development and formation of the 1st instar larva.     

New NF-κB Inhibitory Steroids from the Marine Sponge Dysidea avara Collected from the South China Sea

Chemical investigation of the marine sponge Dysidea avara, collected from the South China Sea, yielded 13 steroids, including nine new ( 1 – 9 ) and four known ( 10 – 13 ) ones. The new structures were elucidated as (3S,14R)-3,14-dihydroxycholesta-5,8-dien-7-one ( 1 ), (22E,24R)-7α-ethoxy-5α,6α-epoxyergosta-8(14),22-dien-3β-ol ( 2 ), 3β-hydroxy-7α-ethoxy-5α,6α-epoxy-8(14)-cholestene ( 3 ), 3β,5α-dihydroxy-6α-ethoxychofesta-7,9(11)-diene ( 4 ), 3β,5α-dihydroxy-6β-ethoxycholest-7-ene ( 5 ), (22E,24R)-24-ethoxy-3β,5α-dihydroxy-6β-ethoxyergosta-7,22-diene ( 6 ), (22E)-3β,5α-dihydroxy-6β-ethoxycholesta-7,22-diene ( 7 ), 24-ethoxy-3β,5α-dihydroxy-6β-ethoxycholest-7-ene ( 8 and 9 ), by extensive spectroscopic analyses, such as HR-ESI-MS, 1D and 2D NMR data. The absolute configuration of 1 was assigned by comparison the experimental ECD spectra with the calculated ones. Among the 13 metabolites, compounds 1 , 4 , 11 , 12 , and 13 showed NF-κB inhibitory activities in human HER-293 cells with IC₅₀ values of 6.4, 18.7, 8.1, 9.6, and 7.5 μM, respectively. Preliminary structure−activity relationship analysis unveiled that the conjugated ketones or unsaturated double bonds might be the functional groups for the five active steroids.     

Precocious metamorphosis of the aphid Myzus persicae induced by the precocene analogue 6-methoxy-7-ethoxy-2,2-dimethylchromene

For up to three days after being treated with the precocene analogue 6-methoxy-7-ethoxy-2,2-dimethylchromene, adult green peach aphids (Myzus persicae) gave birth to offspring (alate and apterous virginoparae, males) which underwent precocious metamorphosis. Only a few precocious gynoparae and no precocious oviparae were recorded. The precocious aphids became adultoid in the third or fourth-instar as a result of corpus allatum destruction. They were able to develop mature embryos, but could not deposit them because of incomplete differentiation of the reproductive tract. The treatment did not induce the production of alate virginoparae in the experimental clone of Myzus persicae. However, a few males were born late in the reproductive sequence of treated apterae. The corpora allata of the treated adults appeared on histological examination to be unaffected by precocene.     

Cytotoxic tirucallane C26 triterpenoids from the stem barks of Aphanamixis grandifolia

Five tirucallane type C₂₆ triterpenoids, accompanied by two known compounds, 3α-hydroxy-24,25,26,27-tetranortirucall-7-ene-23(21)-lactone and 3-oxo-24,25,26,27-tetranortirucall-7-ene-23(21)-lactone, were isolated from the stem barks of Aphanamixis grandifolia. Their structures were established mainly by means of a combination of 1D and 2D NMR spectroscopic and mass spectrometry techniques as 3α-hydroxyl-21α-methoxy-24,25,26,27-tetranortirucall-7-ene-23(21)-lactone, 3α-hydroxy-21β-methoxy-24,25,26,27-tetranortirucall-7-ene-23(21)-lactone, 3-oxo-21α-methoxy-24,25,26,27-tetranortirucall-7-ene-23(21)-lactone, 3-oxo-21β-methoxy-24,25,26,27-tetranortirucall-7-ene-23(21)-lactone, and 3-oxo-21α-ethoxy-24,25,26,27-tetranortirucall-7-ene-23(21)-lactone. All isolates were in vitro evaluated for their cytotoxic activities against five tumor cell lines (MCF-7, HeLa, HepG2, SGC-7901 and BGC-823).